Initial commit

2024-01-20 14:39:54 +00:00 · 2024-01-20 14:39:54 +00:00 · 129a4ecbc9
commit 129a4ecbc9
228 changed files with 18680 additions and 0 deletions
--- a/README.md
+++ b/README.md
@ -0,0 +1,6 @@
+# Books
+
+Code from programming books I work through—both sample code from the books and code
+I write myself.
+
+## Advanced Programming in the UNIX environment
--- a/apitue/01/simple_shell
+++ b/apitue/01/simple_shell
--- a/apitue/01/simple_shell.c
+++ b/apitue/01/simple_shell.c
@ -0,0 +1,44 @@
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+char * get_input(char *buffer, size_t buflen) {
+  printf("$$ ");
+  return fgets(buffer, buflen, stdin);
+}
+
+int main(int argc, char **argv) {
+  char buf[BUFSIZ];
+  pid_t pid;
+  int status;
+
+  // Cast to void to prevent compiler warning
+  (void)argc;
+  (void)argv;
+
+  while(get_input(buf, sizeof(buf))) {
+    buf[strlen(buf) - 1] = '\0';
+
+    if ((pid = fork()) == -1) {
+      fprintf(stderr, "SHELL: Can’t fork: %s\n", strerror(errno));
+      continue;
+    } else if (pid == 0) {
+      execlp(buf, buf, (char *)0);
+      fprintf(stderr, "SHELL: Can’t exec %s: %s\n", buf, strerror(errno));
+      exit(EX_UNAVAILABLE);
+    }
+
+    // Parent waits
+    if ((pid = waitpid(pid, &status, 0)) < 0) {
+      fprintf(stderr, "SHELL: waitpid error: %s\n", strerror(errno));
+    }
+  }
+
+  exit(EX_OK);
+}
--- a/apitue/sample-code/01/fetch-sources.sh
+++ b/apitue/sample-code/01/fetch-sources.sh
@ -0,0 +1,26 @@
+# This file is part of the sample code and exercises
+# used by the class "Advanced Programming in the UNIX
+# Environment" taught by Jan Schaumann
+# <jschauma@netmeister.org> at Stevens Institute of
+# Technology.
+#
+# This file is in the public domain.
+#
+# You don't have to, but if you feel like
+# acknowledging where you got this code, you may
+# reference me by name, email address, or point
+# people to the course website:
+# https://stevens.netmeister.org/631/
+
+#! /bin/sh
+set -eu
+
+umask 022
+
+for set in gnusrc sharesrc src syssrc; do
+	echo "Fetching ${set}..."
+	ftp -V ftp.netbsd.org:/pub/NetBSD/NetBSD-9.3/source/sets/${set}.tgz
+	echo "Extracting ${set}..."
+	su root -c "tar zxf ${set}.tgz -C /"
+	rm -f "${set}.tgz"
+done
--- a/apitue/sample-code/01/hw.c
+++ b/apitue/sample-code/01/hw.c
@ -0,0 +1,26 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char **argv) {
+	/* cast to void to suppress compiler warnings about unused variables */
+	(void)argc;
+	(void)argv;
+
+	printf("Hello, World!\n");
+	exit(EXIT_SUCCESS);
+}
--- a/apitue/sample-code/01/pid.c
+++ b/apitue/sample-code/01/pid.c
@ -0,0 +1,28 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * This trivial program simply prints out its own PID and exits.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+int
+main() {
+	printf("Our process id is %d.\n", getpid());
+	return(EXIT_SUCCESS);
+}
--- a/apitue/sample-code/01/simple-cat.c
+++ b/apitue/sample-code/01/simple-cat.c
@ -0,0 +1,57 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * Stripped down version of 'cat', using unbuffered I/O.
+ * ./simple-cat < simple-cat.c
+ *
+ * Guess what, this is also a primitive version of 'cp':
+ * ./simple-cat <simple-cat.c >simple-cat.copy
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#ifndef BUFFSIZE
+#define BUFFSIZE 32768
+#endif
+
+int
+main(int argc, char **argv) {
+	int n;
+	char buf[BUFFSIZE];
+
+	/* cast to void to silence compiler warnings */
+	(void)argc;
+	(void)argv;
+
+	while ((n = read(STDIN_FILENO, buf, BUFFSIZE)) > 0) {
+		if (write(STDOUT_FILENO, buf, n) != n) {
+			fprintf(stderr, "Unable to write: %s\n",
+strerror(errno));
+			exit(EXIT_FAILURE);
+		}
+	}
+
+	if (n < 0) {
+		fprintf(stderr, "Unable to read: %s\n", strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	return(EXIT_SUCCESS);
+}
--- a/apitue/sample-code/01/simple-cat2.c
+++ b/apitue/sample-code/01/simple-cat2.c
@ -0,0 +1,51 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * Stripped down version of 'cat', buffered version.
+ * Guess what, this is also a primitive version of 'cp':
+ * ./simple-cat <simple-cat.c >simple-cat.copy
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+int
+main(int argc, char **argv) {
+	int c;
+
+	/* cast to void to silence compiler warnings */
+	(void)argc;
+	(void)argv;
+
+	while ((c = getc(stdin)) != EOF) {
+		if (putc(c, stdout) == EOF) {
+			fprintf(stderr, "Unable to write: %s\n",
+					strerror(errno));
+			exit(EXIT_FAILURE);
+		}
+	}
+
+	if (ferror(stdin)) {
+		fprintf(stderr, "Unable to read: %s\n",
+					strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	return(EXIT_SUCCESS);
+}
--- a/apitue/sample-code/01/simple-ls.c
+++ b/apitue/sample-code/01/simple-ls.c
@ -0,0 +1,53 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * simple-ls.c
+ * Extremely low-power ls clone.
+ * ./simple-ls .
+ */
+
+#include <sys/types.h>
+
+#include <errno.h>
+#include <dirent.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int
+main(int argc, char **argv) {
+
+	DIR *dp;
+	struct dirent *dirp;
+
+	if (argc != 2) {
+		fprintf(stderr, "usage: %s dir_name\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	if ((dp = opendir(argv[1])) == NULL) {
+		fprintf(stderr, "Unable to open '%s': %s\n",
+					argv[1], strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	while ((dirp = readdir(dp)) != NULL) {
+		printf("%s\n", dirp->d_name);
+	}
+
+	(void)closedir(dp);
+	return EXIT_SUCCESS;
+}
--- a/apitue/sample-code/01/simple-shell.c
+++ b/apitue/sample-code/01/simple-shell.c
@ -0,0 +1,76 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * World's simplest shell.
+ * Loops, reads input and tries to execute it.
+ * Note: no tokenization, can be ^C'd, but does look at PATH
+ *
+ * ./simple-shell
+ * $$ ls
+ * $$ ls -l # error
+ * $$ ^C
+ *
+ */
+
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+char *
+getinput(char *buffer, size_t buflen) {
+	printf("$$ ");
+	return fgets(buffer, buflen, stdin);
+}
+
+int
+main(int argc, char **argv) {
+	char buf[BUFSIZ];
+	pid_t pid;
+	int status;
+
+	/* cast to void to silence compiler warnings */
+	(void)argc;
+	(void)argv;
+
+	while (getinput(buf, sizeof(buf))) {
+		buf[strlen(buf) - 1] = '\0';
+
+		if((pid=fork()) == -1) {
+			fprintf(stderr, "shell: can't fork: %s\n",
+					strerror(errno));
+			continue;
+		} else if (pid == 0) {   /* child */
+			execlp(buf, buf, (char *)0);
+			fprintf(stderr, "shell: couldn't exec %s: %s\n", buf,
+					strerror(errno));
+			exit(EX_UNAVAILABLE);
+		}
+
+		/* parent waits */
+		if ((pid=waitpid(pid, &status, 0)) < 0) {
+			fprintf(stderr, "shell: waitpid error: %s\n",
+					strerror(errno));
+		}
+	}
+
+	exit(EX_OK);
+}
--- a/apitue/sample-code/01/simple-shell2.c
+++ b/apitue/sample-code/01/simple-shell2.c
@ -0,0 +1,83 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * World's 2nd simplest shell
+ * Same as simple-shell.c, but with a SIGINT signal handler.
+ * Feed EOF (^D) to exit.
+ *
+ * Also illustrates forward declaration of a function prototype.
+ */
+
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+char *
+getinput(char *buffer, size_t buflen) {
+	printf("$$ ");
+	return fgets(buffer, buflen, stdin);
+}
+
+void
+sig_int(int signo) {
+	printf("\nCaught SIGINT (Signal #%d)!\n$$ ", signo);
+	(void)fflush(stdout);
+}
+
+int
+main(int argc, char **argv) {
+	char buf[BUFSIZ];
+	pid_t pid;
+	int status;
+
+	/* cast to void to silence compiler warnings */
+	(void)argc;
+	(void)argv;
+
+	if (signal(SIGINT, sig_int) == SIG_ERR) {
+		fprintf(stderr, "signal error: %s\n", strerror(errno));
+		exit(1);
+	}
+
+	while (getinput(buf, sizeof(buf))) {
+		buf[strlen(buf) - 1] = '\0';
+
+		if((pid=fork()) == -1) {
+			fprintf(stderr, "shell: can't fork: %s\n",
+					strerror(errno));
+			continue;
+		} else if (pid == 0) {   /* child */
+			execlp(buf, buf, (char *)0);
+			fprintf(stderr, "shell: couldn't exec %s: %s\n", buf,
+					strerror(errno));
+			exit(EX_UNAVAILABLE);
+		}
+
+		/* parent waits */
+		if ((pid=waitpid(pid, &status, 0)) < 0) {
+			fprintf(stderr, "shell: waitpid error: %s\n",
+					strerror(errno));
+		}
+	}
+
+	exit(EX_OK);
+}
--- a/apitue/sample-code/01/welcome.c
+++ b/apitue/sample-code/01/welcome.c
@ -0,0 +1,21 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+#include <stdio.h>
+
+int
+main() {
+	printf("Welcome to CS631 Advanced Programming in the UNIX Environment, %s!\n", getlogin())
+}
--- a/apitue/sample-code/02/Makefile
+++ b/apitue/sample-code/02/Makefile
@ -0,0 +1,39 @@
+catio: tmpfiles simple-cat.c
+	@i=0; for n in 3145728 1048576 32768 16384 4096 1024 256 128 64 1; do		\
+		echo "BUFFSIZE = $$n";					\
+		cc -Wall -DBUFFSIZE=$$n simple-cat.c;			\
+		i=$$(( $$i + 1 ));					\
+		for j in $$(jot 5); do					\
+			time ./a.out <tmp/file$$i >tmp/out;			\
+		done; 							\
+		echo;							\
+		echo;							\
+	done;
+
+clean:
+	rm -fr tmp
+
+tmpfiles: tmp/file9
+
+tmp/file9:
+	@mkdir -p tmp
+	@for n in $$(jot 10); do					\
+		echo "Creating file number $$n...";			\
+		dd if=/dev/urandom of=tmp/file$$n bs=$$(( 1024 * 1024 )) count=100 2>/dev/null;\
+	done;
+
+sync: tmpfiles scat
+	time ./scat <tmp/file9 >out
+
+scat: sync-cat.c
+	cc -Wall sync-cat.c -o scat
+
+
+async: tmpfiles ascat
+	time ./ascat <tmp/file9 >out
+
+ascat: async-cat.c
+	cc -Wall $? -o $@
+
+async-cat.c: sync-cat.c
+	sed -e 's|\(.*O_SYNC.*\)|//\1|' sync-cat.c > async-cat.c
--- a/apitue/sample-code/02/argv.c
+++ b/apitue/sample-code/02/argv.c
@ -0,0 +1,49 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* A simple program to show what arguments were passed to a program.  This
+ * can be used to illustrate how different shells expand arguments
+ * differently.
+ *
+ * See also:
+ * http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html
+ * https://wpollock.com/ShScript/CmdLineProcessing.htm
+ *
+ * Examples:
+ * ./a.out
+ * ./a.out *.c
+ * ./a.out *.none
+ * ./a.out *.[1c]
+ * ./a.out "*.c"
+ * ./a.out $USER
+ * ./a.out "$(echo *.1)"
+ * ./a.out {foo,bar,baz}.whatever
+ * ./a.out {1..5}
+ * ./a.out {1..5}{a..f}
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+int
+main(int argc, char **argv) {
+	int i;
+
+	for (i=0; i<argc; i++) {
+		printf("%s\n", argv[i]);
+	}
+
+	return EXIT_SUCCESS;
+}
--- a/apitue/sample-code/02/close-stderr.c
+++ b/apitue/sample-code/02/close-stderr.c
@ -0,0 +1,56 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * This program illustrates that you an close the default
+ * standard I/O filedescriptors.  To reopen, you then need
+ * to explicitly open the terminal device and dup(2) the
+ * descriptor onto it.
+ */
+
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+int
+main() {
+	int fd;
+
+	if ((fd = open("/dev/tty", O_WRONLY)) < 0) {
+		err(EXIT_FAILURE, "Unable to open /dev/tty");
+		/* NOTREACHED */	
+	}
+	(void)printf("Opened /dev/tty on fd#%d.\n", fd);
+
+	(void)printf("Closing STDERR_FILENO...\n");
+	(void)close(STDERR_FILENO);
+
+	(void)fprintf(stderr, "This message will not be shown.\n");
+	if (dup2(fd, STDERR_FILENO) < 0) {
+		/* stderr is still closed */
+		(void)fprintf(stdout, "Unable to dup2: %s\n", strerror(errno));
+		exit(EXIT_FAILURE);
+		/* NOTREACHED */	
+	}
+
+	(void)fprintf(stderr, "Error messages back to normal.\n");
+
+	(void)close(fd);
+	return EXIT_SUCCESS;
+}
--- a/apitue/sample-code/02/dump
+++ b/apitue/sample-code/02/dump
@ -0,0 +1,249 @@
+   173      1 ktrace   EMUL  "netbsd"
+   173      1 ktrace   CALL  execve(0x7f7fff6c5140,0x7f7fff6c5648,0x7f7fff6c5658)
+   173      1 ktrace   NAMI  "/home/jschauma/bin/ls"
+   173      1 ktrace   RET   execve -1 errno 2 No such file or directory
+   173      1 ktrace   CALL  execve(0x7f7fff6c5140,0x7f7fff6c5648,0x7f7fff6c5658)
+   173      1 ktrace   NAMI  "/bin/ls"
+   173      1 ktrace   NAMI  "/libexec/ld.elf_so"
+   173      1 ls       EMUL  "netbsd"
+   173      1 ls       RET   execve JUSTRETURN
+   173      1 ls       CALL  mmap(0,0x8000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597951066112/0x7981b26a8000
+   173      1 ls       CALL  open(0x7f7e4ae0d39f,0,0x7f7e4b012768)
+   173      1 ls       NAMI  "/etc/ld.so.conf"
+   173      1 ls       RET   open -1 errno 2 No such file or directory
+   173      1 ls       CALL  open(0x7f7fff4c7e68,0,1)
+   173      1 ls       NAMI  "/lib/libutil.so.7"
+   173      1 ls       RET   open 3
+   173      1 ls       CALL  __fstat50(3,0x7f7fff4c7d68)
+   173      1 ls       RET   __fstat50 0
+   173      1 ls       CALL  mmap(0,0x1000,PROT_READ,0x1<SHARED,FILE,ALIGN=NONE>,3,0,0)
+   173      1 ls       RET   mmap 133597951062016/0x7981b26a7000
+   173      1 ls       CALL  munmap(0x7981b26a7000,0x1000)
+   173      1 ls       RET   munmap 0
+   173      1 ls       CALL  mmap(0,0x21d000,PROT_READ|PROT_EXEC,0x15000002<PRIVATE,FILE,ALIGN=2MB>,3,0,0)
+   173      1 ls       RET   mmap 133597948280832/0x7981b2400000
+   173      1 ls       CALL  mmap(0x7981b2617000,0x4000,PROT_READ|PROT_WRITE,0x12<PRIVATE,FIXED,FILE,ALIGN=NONE>,3,0,0x17000)
+   173      1 ls       RET   mmap 133597950472192/0x7981b2617000
+   173      1 ls       CALL  mmap(0x7981b261b000,0x2000,PROT_READ|PROT_WRITE,0x1012<PRIVATE,FIXED,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597950488576/0x7981b261b000
+   173      1 ls       CALL  mprotect(0x7981b2417000,0x200000,PROT_NONE)
+   173      1 ls       RET   mprotect 0
+   173      1 ls       CALL  close(3)
+   173      1 ls       RET   close 0
+   173      1 ls       CALL  open(0x7f7fff4c7e68,0,7)
+   173      1 ls       NAMI  "/lib/libc.so.12"
+   173      1 ls       RET   open 3
+   173      1 ls       CALL  __fstat50(3,0x7f7fff4c7d68)
+   173      1 ls       RET   __fstat50 0
+   173      1 ls       CALL  mmap(0,0x1000,PROT_READ,0x1<SHARED,FILE,ALIGN=NONE>,3,0,0)
+   173      1 ls       RET   mmap 133597951062016/0x7981b26a7000
+   173      1 ls       CALL  munmap(0x7981b26a7000,0x1000)
+   173      1 ls       RET   munmap 0
+   173      1 ls       CALL  mmap(0,0x5e2000,PROT_READ|PROT_EXEC,0x15000002<PRIVATE,FILE,ALIGN=2MB>,3,0,0)
+   173      1 ls       RET   mmap 133597941989376/0x7981b1e00000
+   173      1 ls       CALL  mmap(0x7981b21ae000,0x12000,PROT_READ|PROT_WRITE,0x12<PRIVATE,FIXED,FILE,ALIGN=NONE>,3,0,0x1ae000)
+   173      1 ls       RET   mmap 133597945847808/0x7981b21ae000
+   173      1 ls       CALL  mmap(0x7981b21c0000,0x222000,PROT_READ|PROT_WRITE,0x1012<PRIVATE,FIXED,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597945921536/0x7981b21c0000
+   173      1 ls       CALL  mprotect(0x7981b1faf000,0x1ff000,PROT_NONE)
+   173      1 ls       RET   mprotect 0
+   173      1 ls       CALL  close(3)
+   173      1 ls       RET   close 0
+   173      1 ls       CALL  mprotect(0x7981b2617000,0x2000,PROT_READ)
+   173      1 ls       RET   mprotect 0
+   173      1 ls       CALL  mprotect(0x7981b21ae000,0xc000,PROT_READ)
+   173      1 ls       RET   mprotect 0
+   173      1 ls       CALL  mprotect(0x45605000,0x1000,PROT_READ)
+   173      1 ls       RET   mprotect 0
+   173      1 ls       CALL  _lwp_setprivate(0x7981b26ae850)
+   173      1 ls       RET   _lwp_setprivate 0
+   173      1 ls       CALL  _lwp_self
+   173      1 ls       RET   _lwp_self 1
+   173      1 ls       CALL  __sigprocmask14(1,0x7f7fff4c8560,0x7f7fff4c85e0)
+   173      1 ls       RET   __sigprocmask14 0
+   173      1 ls       CALL  __sigprocmask14(3,0x7f7fff4c85e0,0)
+   173      1 ls       RET   __sigprocmask14 0
+   173      1 ls       CALL  readlink(0x7981b1f75420,0x7f7fff4c8040,0x400)
+   173      1 ls       NAMI  "/etc/malloc.conf"
+   173      1 ls       RET   readlink -1 errno 2 No such file or directory
+   173      1 ls       CALL  issetugid
+   173      1 ls       RET   issetugid 0
+   173      1 ls       CALL  __sysctl(0x7f7fff4c83d8,2,0x7981b21d16a0,0x7f7fff4c83d0,0,0)
+   173      1 ls       RET   __sysctl 0
+   173      1 ls       CALL  mmap(0,0x1000,PROT_NONE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597951062016/0x7981b26a7000
+   173      1 ls       CALL  madvise(0x7981b26a7000,0x1000,6)
+   173      1 ls       RET   madvise 0
+   173      1 ls       CALL  munmap(0x7981b26a7000,0x1000)
+   173      1 ls       RET   munmap 0
+   173      1 ls       CALL  mmap(0,0x200000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597939892224/0x7981b1c00000
+   173      1 ls       CALL  __clock_gettime50(3,0x7f7fff4c83d0)
+   173      1 ls       RET   __clock_gettime50 0
+   173      1 ls       CALL  __clock_gettime50(3,0x7f7fff4c83d0)
+   173      1 ls       RET   __clock_gettime50 0
+   173      1 ls       CALL  __clock_gettime50(3,0x7f7fff4c83f0)
+   173      1 ls       RET   __clock_gettime50 0
+   173      1 ls       CALL  mmap(0,0x8000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597951033344/0x7981b26a0000
+   173      1 ls       CALL  mmap(0,0x400000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597935697920/0x7981b1800000
+   173      1 ls       CALL  mmap(0,0x1000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597951029248/0x7981b269f000
+   173      1 ls       CALL  __sysctl(0x7f7fff4c8470,2,0x7f7fff4c8450,0x7f7fff4c8448,0,0)
+   173      1 ls       RET   __sysctl 0
+   173      1 ls       CALL  mmap(0,0x1000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597951025152/0x7981b269e000
+   173      1 ls       CALL  __sysctl(0x7981b1f7b720,2,0x7981b21d0680,0x7f7fff4c84a8,0,0)
+   173      1 ls       RET   __sysctl 0
+   173      1 ls       CALL  _lwp_self
+   173      1 ls       RET   _lwp_self 1
+   173      1 ls       CALL  __sigprocmask14(1,0x7f7fff4c84b0,0x7f7fff4c85e0)
+   173      1 ls       RET   __sigprocmask14 0
+   173      1 ls       CALL  __sigprocmask14(3,0x7f7fff4c85e0,0)
+   173      1 ls       RET   __sigprocmask14 0
+   173      1 ls       CALL  _lwp_self
+   173      1 ls       RET   _lwp_self 1
+   173      1 ls       CALL  __sigprocmask14(1,0x7f7fff4c84b0,0x7f7fff4c85e0)
+   173      1 ls       RET   __sigprocmask14 0
+   173      1 ls       CALL  __sigprocmask14(3,0x7f7fff4c85e0,0)
+   173      1 ls       RET   __sigprocmask14 0
+   173      1 ls       CALL  issetugid
+   173      1 ls       RET   issetugid 0
+   173      1 ls       CALL  mmap(0,0x1000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597951021056/0x7981b269d000
+   173      1 ls       CALL  ioctl(1,TIOCGETA,0x7f7fff4c8580)
+   173      1 ls       GIO   fd 1 read 44 bytes
+       "\^B+\0\0\a\0\0\0\0K\0\0\M-K\^E\0 \^D\M^?\M^?\^?\^W\^U\^R\M^?\^C\^\\^Z\
+	\^Y\^Q\^S\^V\^O\^A\0\^T\M^?\M^@%\0\0\M^@%\0\0"
+   173      1 ls       RET   ioctl 0
+   173      1 ls       CALL  ioctl(1,TIOCGWINSZ,0x7f7fff4c85d8)
+   173      1 ls       GIO   fd 1 read 8 bytes
+       "\^X\0P\0p\^C\^P\^B"
+   173      1 ls       RET   ioctl 0
+   173      1 ls       CALL  getuid
+   173      1 ls       RET   getuid 1000/0x3e8, 1000/0x3e8
+   173      1 ls       CALL  mmap(0,0x5000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597951000576/0x7981b2698000
+   173      1 ls       CALL  mmap(0,0x1000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597950996480/0x7981b2697000
+   173      1 ls       CALL  mmap(0,0x1000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597950992384/0x7981b2696000
+   173      1 ls       CALL  mmap(0,0x1000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597950988288/0x7981b2695000
+   173      1 ls       CALL  __stat50(0x7981b269d0f0,0x7f7fff4c8470)
+   173      1 ls       NAMI  "."
+   173      1 ls       RET   __stat50 0
+   173      1 ls       CALL  open(0x7981b1f7877e,0x400000,0)
+   173      1 ls       NAMI  "."
+   173      1 ls       RET   open 3
+   173      1 ls       CALL  fchdir(3)
+   173      1 ls       RET   fchdir 0
+   173      1 ls       CALL  open(0x7981b1f7877e,0x400000,0)
+   173      1 ls       NAMI  "."
+   173      1 ls       RET   open 4
+   173      1 ls       CALL  open(0x7981b2697000,0x600004,0)
+   173      1 ls       NAMI  "."
+   173      1 ls       RET   open 5
+   173      1 ls       CALL  fstatvfs1(5,0x7f7fff4c7b80,2)
+   173      1 ls       RET   fstatvfs1 0
+   173      1 ls       CALL  mmap(0,0x1000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597950984192/0x7981b2694000
+   173      1 ls       CALL  mmap(0,0x1000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597950980096/0x7981b2693000
+   173      1 ls       CALL  mmap(0,0x1000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597950976000/0x7981b2692000
+   173      1 ls       CALL  mmap(0,0x1000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597950971904/0x7981b2691000
+   173      1 ls       CALL  mmap(0,0x1000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597950967808/0x7981b2690000
+   173      1 ls       CALL  mmap(0,0x1000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597950963712/0x7981b268f000
+   173      1 ls       CALL  mmap(0,0x1000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597950959616/0x7981b268e000
+   173      1 ls       CALL  mmap(0,0x1000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597950955520/0x7981b268d000
+   173      1 ls       CALL  mmap(0,0x1000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597950951424/0x7981b268c000
+   173      1 ls       CALL  mmap(0,0x1000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597950947328/0x7981b268b000
+   173      1 ls       CALL  mmap(0,0x1000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597950943232/0x7981b268a000
+   173      1 ls       CALL  lseek(5,0,0,1)
+   173      1 ls       RET   lseek 0
+   173      1 ls       CALL  __getdents30(5,0x7981b2694000,0x1000)
+   173      1 ls       GIO   fd 5 read 408 bytes
+       "\^O0\^V\0\0\0\0\0\^P\0\^A\0\^D.\0\0\v0\^V\0\0\0\0\0\^P\0\^B\0\^D..\0\
+	\M^Q0\^V\0\0\0\0\0\^X\0\^E\0\bfds.c\0\0\0\0\0\0\M^R0\^V\0\0\0\0\0\^X\0\
+	\^F\0\bhole.c\0\0\0\0\0\M^S0\^V\0\0\0\0\0\^X\0\b\0\bMakefile\0\0\0\M^T\
+	0\^V\0\0\0\0\0\^X\0\n\0\bsync-cat.c\0\M^U0\^V\0\0\0\0\0\^X\0\^F\0\brwe\
+	x.c\0\0\0\0\0\M^V0\^V\0\0\0\0\0\^X\0\a\0\bredir.c\0\0\0\0\M^W0\^V\0\0\
+	\0\0\0\^X\0\a\0\blseek.c\0\0\0\0\M^X0\^V\0\0\0\0\0 \0\f\0\bsimple-cat.\
+	c\0\0\0\0\0\0\0\M^Y0\^V\0\0\0\0\0\^X\0\^F\0\bargv.c\0\0\0\0\0\M^Z0\^V\
+	\0\0\0\0\0\^X\0\b\0\bopenex.c\0\0\0\M^[0\^V\0\0\0\0\0\^X\0	\0\bop\
+	enfds.c\0\0\M^\0\^V\0\0\0\0\0\^X\0	\0\bopenmax.c\0\0\M-C0\^V\0\0\
+	\0\0\0\^X\0\^E\0\ba.out\0\0\0\0\0\0\M-f0\^V\0\0\0\0\0 \0\^N\0\blseek-t\
+	o-end.c\0\0\0\0\0\M-b0\^V\0\0\0\0\0\^X\0\n\0\bktrace.out\0"
+   173      1 ls       RET   __getdents30 408/0x198
+   173      1 ls       CALL  mmap(0,0x5000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597950922752/0x7981b2685000
+   173      1 ls       CALL  lseek(5,0,0,1)
+   173      1 ls       RET   lseek 512/0x200
+   173      1 ls       CALL  __getdents30(5,0x7981b2694000,0x1000)
+   173      1 ls       GIO   fd 5 read 0 bytes
+       ""
+   173      1 ls       RET   __getdents30 0
+   173      1 ls       CALL  close(5)
+   173      1 ls       RET   close 0
+   173      1 ls       CALL  mmap(0,0x7000,PROT_READ|PROT_WRITE,0x1002<PRIVATE,ANONYMOUS,ALIGN=NONE>,0xffffffff,0,0)
+   173      1 ls       RET   mmap 133597950894080/0x7981b267e000
+   173      1 ls       CALL  fchdir(4)
+   173      1 ls       RET   fchdir 0
+   173      1 ls       CALL  close(4)
+   173      1 ls       RET   close 0
+   173      1 ls       CALL  __fstat50(1,0x7f7fff4c7fb0)
+   173      1 ls       RET   __fstat50 0
+   173      1 ls       CALL  ioctl(1,TIOCGETA,0x7f7fff4c8020)
+   173      1 ls       GIO   fd 1 read 44 bytes
+       "\^B+\0\0\a\0\0\0\0K\0\0\M-K\^E\0 \^D\M^?\M^?\^?\^W\^U\^R\M^?\^C\^\\^Z\
+	\^Y\^Q\^S\^V\^O\^A\0\^T\M^?\M^@%\0\0\M^@%\0\0"
+   173      1 ls       RET   ioctl 0
+   173      1 ls       CALL  write(1,0x7981b2694000,0x47)
+   173      1 ls       GIO   fd 1 wrote 71 bytes
+       "Makefile        fds.c           lseek-to-end.c  openfds.c       rwex.c\
+	\n"
+   173      1 ls       RET   write 71/0x47
+   173      1 ls       CALL  write(1,0x7981b2694000,0x4d)
+   173      1 ls       GIO   fd 1 wrote 77 bytes
+       "a.out           hole.c          lseek.c         openmax.c       simple\
+	-cat.c\n"
+   173      1 ls       RET   write 77/0x4d
+   173      1 ls       CALL  write(1,0x7981b2694000,0x4b)
+   173      1 ls       GIO   fd 1 wrote 75 bytes
+       "argv.c          ktrace.out      openex.c        redir.c         sync-c\
+	at.c\n"
+   173      1 ls       RET   write 75/0x4b
+   173      1 ls       CALL  fchdir(3)
+   173      1 ls       RET   fchdir 0
+   173      1 ls       CALL  close(3)
+   173      1 ls       RET   close 0
+   173      1 ls       CALL  _lwp_self
+   173      1 ls       RET   _lwp_self 1
+   173      1 ls       CALL  __sigprocmask14(1,0x7f7fff4c8570,0x7f7fff4c85b0)
+   173      1 ls       RET   __sigprocmask14 0
+   173      1 ls       CALL  __sigprocmask14(3,0x7f7fff4c85b0,0)
+   173      1 ls       RET   __sigprocmask14 0
+   173      1 ls       CALL  _lwp_self
+   173      1 ls       RET   _lwp_self 1
+   173      1 ls       CALL  __sigprocmask14(1,0x7f7fff4c84c0,0x7f7fff4c85b0)
+   173      1 ls       RET   __sigprocmask14 0
+   173      1 ls       CALL  __sigprocmask14(3,0x7f7fff4c85b0,0)
+   173      1 ls       RET   __sigprocmask14 0
+   173      1 ls       CALL  _lwp_self
+   173      1 ls       RET   _lwp_self 1
+   173      1 ls       CALL  __sigprocmask14(1,0x7f7fff4c84c0,0x7f7fff4c85b0)
+   173      1 ls       RET   __sigprocmask14 0
+   173      1 ls       CALL  __sigprocmask14(3,0x7f7fff4c85b0,0)
+   173      1 ls       RET   __sigprocmask14 0
+   173      1 ls       CALL  exit(0)
--- a/apitue/sample-code/02/fds.c
+++ b/apitue/sample-code/02/fds.c
@ -0,0 +1,85 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * A program to show the value of some file
+ * descriptors.
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+int
+main() {
+	int fd1, fd2, fd3;
+	FILE *f;
+
+	printf("STDIN_FILENO: %d\n", STDIN_FILENO);
+	printf("stdin: %d\n", fileno(stdin));
+	printf("STDOUT_FILENO: %d\n", STDOUT_FILENO);
+	printf("stdout: %d\n", fileno(stdout));
+	printf("STDERR_FILENO: %d\n", STDERR_FILENO);
+	printf("stderr: %d\n", fileno(stderr));
+
+	printf("\nOpening /dev/zero...\n");
+	if ((fd1 = open("/dev/zero", O_RDONLY)) < 0) {
+		fprintf(stderr, "Unable to open /dev/zero: %s\n", strerror(errno));
+	} else {
+		printf("fd1: %d\n", fd1);
+	}
+
+	printf("\nOpening /dev/zero a second time...\n");
+	if ((fd2 = open("/dev/zero", O_RDONLY)) < 0) {
+		fprintf(stderr, "Unable to open /dev/zero: %s\n", strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+	printf("fd2: %d\n", fd2);
+
+	printf("\nNow closing fd1, but keeping fd2 open..\n");
+	(void)close(fd1);
+
+	printf("\nOpening /dev/zero a third time...\n");
+	if ((fd3 = open("/dev/zero", O_RDONLY)) < 0) {
+		fprintf(stderr, "Unable to open /dev/zero: %s\n", strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+	printf("fd3: %d\n", fd3);
+
+	printf("\nNow closing fd2 and fd3.\n");
+	(void)close(fd2);
+	(void)close(fd3);
+
+	printf("Now opening /dev/zero as a stream.\n");
+	if ((f = fopen("/dev/zero", "r")) == NULL) {
+		fprintf(stderr, "Unable to open /dev/zero: %s\n", strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+	printf("f: %d\n", fileno(f));
+	(void)fclose(f);
+
+	(void)close(STDERR_FILENO);
+	printf("\nOpening /dev/stderr after closing STDERR...\n");
+	if ((fd3 = open("/dev/stderr", O_RDONLY)) < 0) {
+		fprintf(stdout, "Unable to open /dev/stderr: %s\n", strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+	printf("stderr is now: %d\n", fd3);
+
+	return EXIT_SUCCESS;
+}
--- a/apitue/sample-code/02/hole.c
+++ b/apitue/sample-code/02/hole.c
@ -0,0 +1,64 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * This simple program creates a file with a hole in it, a so-called
+ * sparse file.  Use hexdump(1) or od(1) to verify that there is no data
+ * in between the two strings; then copy the file to to another and
+ * observe that the kernel supplied zeros to fill the hole.
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+char buf1[] = "abcdefghij";
+char buf2[] = "ABCDEFGHIJ";
+
+#define BIGNUM 10240000
+
+int
+main(void) {
+	int fd;
+
+	if ((fd = creat("file.hole", S_IRUSR | S_IWUSR)) < 0) {
+		perror("creat error");
+		return EXIT_FAILURE;
+	}
+
+	if (write(fd, buf1, strlen(buf1)) != sizeof(buf1) - 1) {
+		perror("error writing buf1");
+		return EXIT_FAILURE;
+	}
+
+	if (lseek(fd, BIGNUM, SEEK_CUR) == -1) {
+		perror("lseek error");
+		return EXIT_FAILURE;
+	}
+
+	if (write(fd, buf2, strlen(buf2)) != sizeof(buf2) - 1) {
+		perror("error writing buf2");
+		return EXIT_FAILURE;
+	}
+	sleep(30);
+
+	(void)close(fd);
+	return EXIT_SUCCESS;
+}
--- a/apitue/sample-code/02/ktrace.out
+++ b/apitue/sample-code/02/ktrace.out
--- a/apitue/sample-code/02/lseek-to-end.c
+++ b/apitue/sample-code/02/lseek-to-end.c
@ -0,0 +1,73 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * This program creates a new file, writes ten bytes to it
+ * and then seeks to the end of the file.  Where do we end up?
+ */
+
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define DATA "0123456789"
+
+void
+printOffset(int fd, int whence) {
+	off_t off;
+
+	if ((off = lseek(fd, 0, whence)) == -1) {
+		err(EXIT_FAILURE, "Unable to lseek");
+		/* NOTREACHED */
+	}
+	(void)printf("Offset: %d\n", (int)off);
+}
+
+int
+main(void) {
+	int fd;
+	int len;
+
+	if ((fd = open("f", O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR)) == -1) {
+		err(EXIT_FAILURE, "Unable create file 'f'");
+		/* NOTREACHED */
+	}
+
+	printOffset(fd, SEEK_CUR);
+
+	len = sizeof(DATA) - 1;
+	if (write(fd, DATA, len) != len) {
+		err(EXIT_FAILURE, "Unable write");
+		/* NOTREACHED */
+	}
+
+	printOffset(fd, SEEK_CUR);
+	printOffset(fd, SEEK_END);
+	(void)close(fd);
+
+	if (unlink("f") < 0) {
+		err(EXIT_FAILURE, "Unable to unlink 'f'");
+		/* NOTREACHED */
+	}
+
+	return EXIT_SUCCESS;
+}
--- a/apitue/sample-code/02/lseek.c
+++ b/apitue/sample-code/02/lseek.c
@ -0,0 +1,35 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * This trivial program verifies whether or not STDIN is seekable.  Test
+ * on a regular file, on a pipe or a fifo.
+ */
+
+#include <sys/types.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+int
+main(void) {
+	if (lseek(STDIN_FILENO, 0, SEEK_CUR) == -1 )
+		printf("cannot seek\n");
+	else
+		printf("seek OK\n");
+
+	return EXIT_SUCCESS;
+}
--- a/apitue/sample-code/02/openat.c
+++ b/apitue/sample-code/02/openat.c
@ -0,0 +1,162 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * This program illustrates the usefulness of openat(2) to avoid
+ * certain race conditions:
+ *
+ * Assume that you want to open the files "file1" and "file2" found
+ * in the directory "../dir".  You might start out using
+ *
+ * fd1 = open("../dir/file1", ...)
+ * fd2 = open("../dir/file2", ...)
+ *
+ * However, in between these two calls, another process might have
+ * renamed the directory "../dir" to "../dir2", then created "../dir"
+ * and placed a different file named "file2" into it.  Your program
+ * now has opened two files from two different directories.
+ *
+ * With openat(2), you could guarantee that the call to open "file2"
+ * will use the same directory as the call to open "file1":
+ *
+ * dfd = open("../dir/", O_DIRECTORY ...)
+ * fd1 = openat(dfd, "file1", ...)
+ * fd2 = openat(dfd, "file2", ...)
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+void
+readData(int fd) {
+	int n;
+	char buf[BUFSIZ];
+	bzero(buf, BUFSIZ);
+	if ((n = read(fd, buf, BUFSIZ)) == -1) {
+		(void)fprintf(stderr, "Unable to read data from fd %d: %s\n",
+				fd, strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	(void)printf("Read data: %s", buf);
+}
+
+void
+readFileUsingOpenat(const int dfd, const char *f) {
+	int fd;
+
+	(void)printf("Opening '%s' using openat(2)...\n", f);
+	if ((fd = openat(dfd, f, O_RDONLY)) == -1) {
+		(void)fprintf(stderr, "Unable to open '%s': %s\n",
+				f, strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	readData(fd);
+}
+
+void
+readFileUsingOpen(const char *f) {
+	int fd;
+
+	(void)printf("Opening '%s'...\n", f);
+
+	if ((fd = open(f, O_RDONLY)) == -1) {
+		(void)fprintf(stderr, "Unable to open '%s': %s\n",
+				f, strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	readData(fd);
+}
+
+void
+reset() {
+	system("rm -fr ../dir");
+	system("mv ../dir2 ../dir");
+}
+
+void
+makeFiles() {
+}
+
+void
+setup() {
+	/* Trivial setup via system(3) because we're lazy. */
+	system("mkdir -p ./t ./dir");
+	system("echo file1 > ./dir/file1");
+	system("echo file2 > ./dir/file2");
+
+	if (chdir("./t") < 0) {
+		(void)fprintf(stderr, "Unable to cd to './t': %s\n", strerror(errno));
+		exit(EXIT_FAILURE);
+		/* NOTREACHED */
+	}
+}
+
+void
+simulateRaceCondition() {
+	(void)printf("Simulating race condition by renaming '../dir'...\n");
+	system("mv ../dir ../dir2");
+	system("mkdir ../dir");
+	system("echo notfile2 > ../dir/file2");
+}
+
+void
+cleanup() {
+	if (chdir("..") < 0) {
+		(void)fprintf(stderr, "Unable to register exit handler: %s\n",
+				strerror(errno));
+	} else {
+		system("rm -fr t dir dir2");
+	}
+}
+
+int
+main() {
+
+	if (atexit(cleanup) < 0) {
+		(void)fprintf(stderr, "Unable to register exit handler: %s\n",
+				strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	setup();
+
+	readFileUsingOpen("../dir/file1");
+	simulateRaceCondition();
+	readFileUsingOpen("../dir/file2");
+
+	reset();
+
+	(void)printf("\nLet's try again...\n\n");
+
+	int dfd;
+	if ((dfd = open("../dir", O_RDONLY | O_DIRECTORY)) == -1) {
+		(void)fprintf(stderr, "Unable to open directory '../dir': %s\n",
+				strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	readFileUsingOpenat(dfd, "file1");
+	simulateRaceCondition();
+	readFileUsingOpenat(dfd, "file2");
+
+	return EXIT_SUCCESS;
+}
--- a/apitue/sample-code/02/openex.c
+++ b/apitue/sample-code/02/openex.c
@ -0,0 +1,170 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * This trivial program illustrates how to open files.  We present the
+ * following use cases:
+ *
+ * - create a non-existent file
+ * - "create" an existing file
+ * - fail to create an existing file
+ * - open an existing file
+ * - fail to open a non-existing file
+ * - truncate an existing file
+ */
+
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#ifndef SLEEP
+#define SLEEP 10
+#endif
+
+void
+createFile() {
+	int fd;
+
+	printf("Checking if './newfile' exists...\n");
+	system("ls -l ./newfile");
+	printf("Trying to create './newfile' with O_RDONLY | O_CREAT...\n");
+
+	if ((fd = open("./newfile", O_RDONLY | O_CREAT,
+					S_IRUSR | S_IWUSR)) == -1) {
+		fprintf(stderr, "Unable to create './newfile': %s\n",
+				strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	printf("'./newfile' created. File descriptor is: %d\n", fd);
+
+	/* We are leaking a file descriptor here to illustrate that they
+	 * are increasing as we open more files.  Normally, we would call
+	 * close(2) whenever we're done using the decriptor. */
+}
+
+void
+failExclFileCreation() {
+	int fd;
+
+	printf("Checking if './newfile' exists...\n");
+	system("ls -l ./newfile");
+	printf("Trying to create './newfile' with O_RDONLY | O_CREAT | O_EXCL...\n");
+
+	if ((fd = open("./newfile", O_RDONLY | O_CREAT | O_EXCL,
+					S_IRUSR | S_IWUSR)) == -1) {
+		fprintf(stderr, "Unable to create './newfile': %s\n",
+				strerror(errno));
+	}
+
+	/* We expect this to fail! */
+	if (close(fd) == -1) {
+		fprintf(stderr, "Closing failed: %s\n", strerror(errno));
+	}
+}
+
+
+void
+failOpenNonexistingFile() {
+	int fd;
+
+	printf("Trying to open (non-existant) './nosuchfile' with O_RDONLY...\n");
+
+	if ((fd = open("./nosuchfile", O_RDONLY)) == -1) {
+		fprintf(stderr, "Unable to open './nosuchfile': %s\n",
+				strerror(errno));
+	}
+
+	/* We know this is going to fail, but no need to complain. */
+	(void)close(fd);
+}
+
+void
+openFile() {
+	int fd;
+
+	printf("Trying to open './openex.c' with O_RDONLY...\n");
+
+	if ((fd = open("./openex.c", O_RDONLY)) == -1) {
+		fprintf(stderr, "Unable to open './openex.c': %s\n",
+				strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	printf("'./openex.c' opened. File descriptor is: %d\n", fd);
+
+	if (close(fd) == 0) {
+		printf("'./openex.c' closed again\n");
+	}
+}
+
+void
+truncateFile() {
+	int fd;
+
+	system("cp openex.c newfile");
+	printf("Copied 'openex.c' to 'newfile'.\n");
+	system("ls -l newfile");
+
+	printf("Trying to open './newfile' with O_RDONLY | O_TRUNC...\n");
+
+	if ((fd = open("./newfile", O_RDONLY | O_TRUNC)) == -1) {
+		fprintf(stderr, "Unable to open './newfile': %s\n",
+				strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	printf("'./newfile' opened. File descriptor is: %d\n", fd);
+	printf("'./newfile' truncated -- see 'ls -l newfile'\n");
+	system("ls -l newfile");
+
+	(void)close(fd);
+}
+
+
+
+int
+main() {
+	createFile();
+	system("ls -l newfile");
+	printf("\n");
+	sleep(SLEEP);
+
+	createFile();
+	system("ls -l newfile");
+	printf("\n");
+	sleep(SLEEP);
+
+	failExclFileCreation();
+	printf("\n");
+	sleep(SLEEP);
+
+	openFile();
+	printf("\n");
+	sleep(SLEEP);
+
+	failOpenNonexistingFile();
+	printf("\n");
+	sleep(SLEEP);
+
+	truncateFile();
+
+	return 0;
+}
--- a/apitue/sample-code/02/openfds.c
+++ b/apitue/sample-code/02/openfds.c
@ -0,0 +1,122 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * This trivial program attempts to determine how many
+ * open files a process can have.  It illustrates the
+ * use of pre-processor directives and sysconf(3) to
+ * identify a resource that can be changed at system
+ * run time.
+ *
+ * This program also asks getconf(1) and explicitly
+ * asks getrlimit(2).  Look at the source code for
+ * getconf(1) and sysconf(3) to show how they are
+ * implemented, as well as manual page and
+ * implementation of getdtablesize(3).
+ *
+ * Run this once, then use 'ulimit -n' to change the
+ * limit and run again.
+ *
+ * If you (as root) set 'ulimit -n unlimited', what
+ * value will you get?  Why?
+ *
+ * What happens if you set this limit to, say, 0?
+ * Why?
+ */
+
+#include <sys/resource.h>
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+int
+countOpenFiles(int num) {
+	struct stat stats;
+	int count = 0;
+	for (int i = 0; i < num; i++) {
+		if (fstat(i, &stats) == 0) {
+			printf("Currently open: fd #%d (inode %ld)\n", i,
+					stats.st_ino);
+			count++;
+		}
+	}
+
+	return count;
+}
+
+void
+openFiles(int num) {
+	int count, fd;
+
+	count = countOpenFiles(num);
+
+	printf("Currently open files: %d\n", count);
+
+	for (int i = count; i <= num ; i++) {
+		if ((fd = dup(0)) < 0) {
+			fprintf(stderr, "%d: Unable to dup fd0: %s (%d)\n", i, strerror(errno), errno);
+			break;
+		}
+	}
+}
+
+int
+main() {
+	int openmax;
+	struct rlimit rlp;
+
+#ifdef OPEN_MAX
+	printf("OPEN_MAX is defined as %d.\n", OPEN_MAX);
+#else
+	printf("OPEN_MAX is not defined on this platform.\n");
+#endif
+
+	printf("'getconf OPEN_MAX' says: ");
+	(void)fflush(stdout);
+	(void)system("getconf OPEN_MAX");
+
+	/* see also: getdtablesize(3), notably the HISTORY section */
+	errno = 0;
+	if ((openmax = sysconf(_SC_OPEN_MAX)) < 0) {
+		if (errno == 0) {
+			fprintf(stderr, "sysconf(3) considers _SC_OPEN_MAX unsupported?\n");
+		} else {
+			fprintf(stderr, "sysconf(3) error for _SC_OPEN_MAX: %s\n",
+					strerror(errno));
+		}
+		exit(EXIT_FAILURE);
+		/* NOTREACHED */
+	}
+	printf("sysconf(3) says this process can open %d files.\n", openmax);
+
+	if (getrlimit(RLIMIT_NOFILE, &rlp) != 0) {
+		fprintf(stderr, "Unable to get per process rlimit: %s\n", strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+	openmax = (int)rlp.rlim_cur;
+	printf("getrlimit(2) says this process can open %d files.\n", openmax);
+
+	printf("Which one is it?\n\n");
+
+	openFiles(openmax);
+
+	return EXIT_SUCCESS;
+}
--- a/apitue/sample-code/02/openmax.c
+++ b/apitue/sample-code/02/openmax.c
@ -0,0 +1,129 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * This trivial program attempts to determine how many
+ * open files a process can have.  It illustrates the
+ * use of pre-processor directives and sysconf(3) to
+ * identify a resource that can be changed at system
+ * run time.
+ *
+ * This program also asks getconf(1) and explicitly
+ * asks getrlimit(2).  Look at the source code for
+ * getconf(1) and sysconf(3) to show how they are
+ * implemented, as well as manual page and
+ * implementation of getdtablesize(3).
+ *
+ * Run this once, then use 'ulimit -n' to change the
+ * limit and run again.
+ *
+ * If you (as root) set 'ulimit -n unlimited', what
+ * value will you get?  Why?
+ *
+ * What happens if you set this limit to, say, 0?
+ * Why?
+ */
+
+#include <sys/resource.h>
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+int
+countOpenFiles(int num) {
+	struct stat stats;
+	int count = 0;
+	for (int i = 0; i < num; i++) {
+		if (fstat(i, &stats) == 0) {
+			printf("Currently open: fd #%d (inode %ld)\n", i,
+					stats.st_ino);
+			count++;
+		}
+	}
+
+	return count;
+}
+
+void
+openFiles(int num) {
+	int count, fd;
+
+	count = countOpenFiles(num);
+
+	printf("Currently open files: %d\n", count);
+
+	for (int i = count; i <= num ; i++) {
+		if ((fd = open("/dev/null", O_RDONLY)) < 0) {
+			if (errno == EMFILE) {
+				printf("Opened %d additional files, then failed: %s (%d)\n", i - count, strerror(errno), errno);
+				break;
+			} else {
+				fprintf(stderr, "Unable to open '/dev/null' on fd#%d: %s (errno %d)\n",
+						i, strerror(errno), errno);
+				break;
+			}
+		}
+	}
+}
+
+int
+main() {
+	int openmax;
+	struct rlimit rlp;
+
+#ifdef OPEN_MAX
+	printf("OPEN_MAX is defined as %d.\n", OPEN_MAX);
+#else
+	printf("OPEN_MAX is not defined on this platform.\n");
+#endif
+
+
+	printf("'getconf OPEN_MAX' says: ");
+	(void)fflush(stdout);
+	(void)system("getconf OPEN_MAX");
+
+	/* see also: getdtablesize(3), notably the HISTORY section */
+	errno = 0;
+	if ((openmax = sysconf(_SC_OPEN_MAX)) < 0) {
+		if (errno == 0) {
+			fprintf(stderr, "sysconf(3) considers _SC_OPEN_MAX unsupported?\n");
+		} else {
+			fprintf(stderr, "sysconf(3) error for _SC_OPEN_MAX: %s\n",
+					strerror(errno));
+		}
+		exit(EXIT_FAILURE);
+		/* NOTREACHED */
+	}
+	printf("sysconf(3) says this process can open %d files.\n", openmax);
+
+	if (getrlimit(RLIMIT_NOFILE, &rlp) != 0) {
+		fprintf(stderr, "Unable to get per process rlimit: %s\n", strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+	openmax = (int)rlp.rlim_cur;
+	printf("getrlimit(2) says this process can open %d files.\n", openmax);
+
+	printf("Which one is it?\n\n");
+
+	openFiles(openmax);
+
+	return EXIT_SUCCESS;
+}
--- a/apitue/sample-code/02/redir.c
+++ b/apitue/sample-code/02/redir.c
@ -0,0 +1,65 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * This simple program illustrates output redirection via dup(2).
+ *
+ * Compare:
+ * ./a.out
+ * ./a.out >/dev/null
+ * ./a.out 2>/dev/null
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define STDOUT_MSG "A message to stdout.\n"
+#define STDERR_MSG "A message to stderr.\n"
+
+void
+writeBoth(const char *mark) {
+	int len, marklen;
+
+	marklen = strlen(mark);
+	if (write(STDOUT_FILENO, mark, marklen) != marklen) {
+		perror("unable to write marker to stdout");
+		exit(EXIT_FAILURE);
+	}
+
+	len = strlen(STDOUT_MSG);
+	if (write(STDOUT_FILENO, STDOUT_MSG, len) != len) {
+		perror("unable to write to stdout");
+		exit(EXIT_FAILURE);
+	}
+
+	if (write(STDERR_FILENO, STDERR_MSG, len) != len) {
+		perror("unable to write to stdout");
+		exit(EXIT_FAILURE);
+	}
+}
+
+int
+main() {
+	writeBoth("before dup2\n");
+
+	if (dup2(STDOUT_FILENO, STDERR_FILENO) < 0) {
+		perror("Unable to redirect stderr to stdout");
+		exit(EXIT_FAILURE);
+	}
+
+	writeBoth("after dup2\n");
+}
--- a/apitue/sample-code/02/rwex.c
+++ b/apitue/sample-code/02/rwex.c
@ -0,0 +1,72 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * This trivial program illustrates how we might normally read and write
+ * to a simple file. Here, we simply open the source code file, read the
+ * first few bytes, then append a comment.
+ *
+ * What happens if we do not open with O_APPEND?
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define BUFFSIZE	64
+#define COMMENT		"\n/* Just another comment. */\n"
+#define SOURCE 		"./rwex.c"
+
+int
+main() {
+	int fd, n;
+	int len;
+	char buf[BUFFSIZE];
+
+	if ((fd = open(SOURCE, O_RDWR | O_APPEND)) == -1) {
+		fprintf(stderr, "Unable to open '%s': %s\n",
+				SOURCE, strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	if ((n = read(fd, buf, BUFFSIZE)) > 0) {
+		if (write(STDOUT_FILENO, buf, n) != n) {
+			fprintf(stderr, "Unable to write: %s\n",
+					strerror(errno));
+			exit(EXIT_FAILURE);
+		}
+	} else if (n == -1) {
+		fprintf(stderr, "Error reading from %s: %s\n",
+				SOURCE, strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	printf("\n\nOk, we read the first %d bytes. Now let's write something.\n", BUFFSIZE);
+
+	len = sizeof(COMMENT) - 1;
+	if (write(fd, COMMENT, len) != len) {
+		fprintf(stderr, "Unable to write: %s\n",
+				strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	(void)close(fd);
+	return EXIT_SUCCESS;
+}
+
+/* Just another comment. */
--- a/apitue/sample-code/02/simple-cat.c
+++ b/apitue/sample-code/02/simple-cat.c
@ -0,0 +1,57 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * Stripped down version of 'cat', using unbuffered I/O.
+ * ./simple-cat < simple-cat.c
+ *
+ * Guess what, this is also a primitive version of 'cp':
+ * ./simple-cat <simple-cat.c >simple-cat.copy
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#ifndef BUFFSIZE
+#define BUFFSIZE 32768
+#endif
+
+int
+main(int argc, char **argv) {
+	int n;
+	char buf[BUFFSIZE];
+
+	/* cast to void to silence compiler warnings */
+	(void)argc;
+	(void)argv;
+
+	while ((n = read(STDIN_FILENO, buf, BUFFSIZE)) > 0) {
+		if (write(STDOUT_FILENO, buf, n) != n) {
+			fprintf(stderr, "Unable to write: %s\n",
+strerror(errno));
+			exit(EXIT_FAILURE);
+		}
+	}
+
+	if (n < 0) {
+		fprintf(stderr, "Unable to read: %s\n", strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	return(EXIT_SUCCESS);
+}
--- a/apitue/sample-code/02/sync-cat.c
+++ b/apitue/sample-code/02/sync-cat.c
@ -0,0 +1,79 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* simple-cat.c, O_SYNC version
+ *
+ * Use this program to illustrate the use of fcntl(2)
+ * to set the O_SYNC flag on STDOUT, which we do not
+ * open ourselves, so can't set that flag on at that
+ * time.
+ *
+ * This also illustrates the difference between
+ * synchronous and asynchronous I/O:
+ *
+ * Create a large enough file:
+ *
+ * dd if=/dev/zero of=file bs=$((1024 * 1024)) count=25
+ *
+ * Then run this program:
+ *
+ * time ./a.out <file >out
+ *
+ * Then, comment out the setting of O_SYNC, recompile
+ * the program and run it again.
+ */
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#define BUFFSIZE 512
+
+int
+main(int argc, char **argv) {
+	int n;
+	char buf[BUFFSIZE];
+	int flags;
+
+	/* cast to void to silence compiler warnings */
+	(void)argc;
+	(void)argv;
+
+	if ((flags = fcntl(STDOUT_FILENO, F_GETFL, 0)) < 0) {
+		perror("Can't get file descriptor flags");
+		exit(EXIT_FAILURE);
+	}
+
+	//flags |= O_SYNC;
+
+	if (fcntl(STDOUT_FILENO, F_SETFL, flags) < 0) {
+		perror("Can't set file descriptor flags");
+		exit(EXIT_FAILURE);
+	}
+
+	while ((n = read(STDIN_FILENO, buf, BUFFSIZE)) > 0 )
+		if ( write(STDOUT_FILENO, buf, n) != n ) {
+			perror("write error");
+			exit(EXIT_FAILURE);
+		}
+
+	if (n < 0) {
+		perror("read error");
+		exit(EXIT_FAILURE);
+	}
+
+	return EXIT_SUCCESS;
+}
--- a/apitue/sample-code/02/writeseek.c
+++ b/apitue/sample-code/02/writeseek.c
@ -0,0 +1,59 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * If you create a new file, write, say,
+ * 10 bytes of data, and then seek to the
+ * end of the file, where do you end up? Why?
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define WFILE "/tmp/rw"
+#define DLEN 10
+
+int
+main() {
+	int fd, n;
+	char data[DLEN];
+	bzero(data, DLEN);
+
+	if ((fd = open(WFILE, O_RDWR | O_CREAT | O_EXCL, 0700)) == -1) {
+		fprintf(stderr, "Unable to open '%s': %s\n",
+				WFILE, strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	if (write(fd, data, DLEN) != DLEN) {
+		fprintf(stderr, "Unable to write: %s\n",
+					strerror(errno));
+			exit(EXIT_FAILURE);
+	}
+
+	if ((n = lseek(fd, 0, SEEK_END)) == 0) {
+		fprintf(stderr, "Unable to seek: %s\n",
+				strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+	printf("Seeked to offset %d\n", n);
+
+	(void)close(fd);
+	return EXIT_SUCCESS;
+}
--- a/apitue/sample-code/03/access.c
+++ b/apitue/sample-code/03/access.c
@ -0,0 +1,46 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* This trivial program illustrates the use of access(2).  Compile this
+ * program and run it with /etc/passwd, /etc/master.passwd as arguments;
+ * then chown and setuid the executable and repeat.
+ */
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+int
+main(int argc, char **argv) {
+
+	if (argc != 2) {
+		fprintf(stderr, "%s: usage: %s filename\n", argv[0], argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	if (access(argv[1], R_OK) == -1)
+		printf("access error for %s\n", argv[1]);
+	else
+		printf("access ok for %s\n", argv[1]);
+
+
+	if (open(argv[1], O_RDONLY) == -1)
+		printf("open error for %s\n", argv[1]);
+	else
+		printf("open ok for %s\n", argv[1]);
+
+	exit(EXIT_SUCCESS);
+}
--- a/apitue/sample-code/03/chmod.c
+++ b/apitue/sample-code/03/chmod.c
@ -0,0 +1,51 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* This simple program illustrates the use of the chmod(2) system call,
+ * and how it can be used to set explicit/absolute modes or to selectively
+ * enable individual modes.
+ *
+ * Set your umask to 077, create file and file1, then run this command.
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+
+int
+main() {
+	struct stat sbuf;
+
+	if (stat("file", &sbuf) == -1) {
+		perror("can't stat file");
+		exit(EXIT_FAILURE);
+	}
+
+	/* turn off owner read permissions and turn on setgid */
+	if (chmod("file", (sbuf.st_mode & ~S_IRUSR) | S_ISGID) == -1) {
+		perror("can't chmod file");
+		exit(EXIT_FAILURE);
+	}
+
+	/* set absolute mode to rw-r--r-- */
+	if (chmod("file1", S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH) == -1) {
+		perror("can't chmod file1");
+		exit(EXIT_FAILURE);
+	}
+
+	exit(EXIT_SUCCESS);
+}
--- a/apitue/sample-code/03/chown.c
+++ b/apitue/sample-code/03/chown.c
@ -0,0 +1,76 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* This simple program illustrates the use of the chown(2) system call:
+ *
+ * touch file
+ * ./a.out
+ * ls -l file
+ * sudo ./a.out
+ * ls -l file
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+/* We'll see better ways to get a user's UID or a
+ * group's GID in our next lecture. */
+#define FRED 1001
+#define USERS_GID 100
+#define TTY_GID 4
+
+void
+mychown(const char *file, int uid, int gid) {
+	if (chown(file, uid, gid) < 0) {
+		fprintf(stderr, "Unable to chown(%s, %d, %d): %s\n",
+				file, uid, gid, strerror(errno));
+	} else {
+		printf("Successfully chowned %s to %d:%d.\n",
+				file, uid, gid);
+	}
+}
+
+int
+main(int argc, char **argv) {
+
+	if (argc != 2) {
+		fprintf(stderr, "Usage: %s file\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	/* Let's try to take ownership of the file.
+	 * That's not really a useful thing to try,
+	 * since either it works out, in which case
+	 * we already owned the file, or it'll fail.
+	 *
+	 * Unless, of course, we're root... */
+	mychown(argv[1], getuid(), -1);
+
+	/* Next, let's try to change ownership to
+	 * Fred.  (Don't hold your breath, unless
+	 * you're root.) */
+	mychown(argv[1], FRED, -1);
+
+	/* Next, let's 'chown:users'... */
+	mychown(argv[1], -1, USERS_GID);
+
+	/* ... and let's try 'chown:tty'. */
+	mychown(argv[1], -1, TTY_GID);
+
+	exit(EXIT_SUCCESS);
+}
--- a/apitue/sample-code/03/direntsize.c
+++ b/apitue/sample-code/03/direntsize.c
@ -0,0 +1,48 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* This program prints out the amount of space
+ * required to represent a directory entry in the Unix
+ * File System per <ufs/ufs/dir.h>.
+ *
+ * ./a.out filename
+ *
+ * You should be able to determine how many files of a
+ * given filename length you can create in a directory
+ * without that directory size increasing.
+ *
+ * Note that once a directory size has increased,
+ * removing files from it will not shrink it again
+ * (on UFS/FFS).
+ */
+
+#include <sys/types.h>
+
+#include <ufs/ufs/dir.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int
+main(int argc, char **argv) {
+	if (argc != 2) {
+		fprintf(stderr, "Usage: %s name\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	printf("%ld\n", UFS_DIRECTSIZ(strlen(argv[1])));
+	exit(EXIT_SUCCESS);
+}
--- a/apitue/sample-code/03/myuids.c
+++ b/apitue/sample-code/03/myuids.c
@ -0,0 +1,91 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* A simple program to illustrate the difference
+ * between effective and real user IDs.
+ *
+ * Compile, then run as user1 and user2:
+ * user1$ cc myuids.c
+ * user1$ ./a.out
+ * user2$ ./a.out
+ * user1$ chmod u+s a.out
+ * user1$ ./a.out
+ * user2$ ./a.out
+ *
+ * For a more complete, albeit notably more complex
+ * illustration of the various uids and the handling
+ * of saved-setuid bits, see setuid.c and the comments
+ * and links in there.
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+void
+printUids() {
+	uid_t ruid = getuid();
+	uid_t euid = geteuid();
+
+	printf("My effective uid is: %d\n", euid);
+	printf("My real uid is: %d\n", ruid);
+}
+
+int
+main() {
+	printUids();
+
+	uid_t ruid = getuid();
+	uid_t euid = geteuid();
+	if (ruid == euid) {
+		/* Nothing meaningful to do here. */
+		exit(EXIT_SUCCESS);
+		/* NOTREACHED */
+	}
+
+	printf("\nLet's drop elevated privs and set our effective uid to our real uid.\n");
+	printf("Calling 'seteuid(%d)'...\n", ruid);
+	if (seteuid(ruid) < 0) {
+		fprintf(stderr, "Unable to seteuid(%d): %s\n", ruid, strerror(errno));
+	} else {
+		printUids();
+	}
+
+	printf("\nBecause we used seteuid(%d) and not setuid(%d), we can get back our earlier euid %d.\n", ruid, ruid, euid);
+	printf("Calling 'seteuid(%d)'...\n", euid);
+	if (seteuid(euid) < 0) {
+		fprintf(stderr, "Unable to seteuid(%d): %s\n", euid, strerror(errno));
+	} else {
+		printUids();
+	}
+
+	printf("\nNow let's try to 'setuid(%d)'...\n", ruid);
+	if (setuid(ruid) < 0) {
+		fprintf(stderr, "Unable to setuid(%d): %s\n", ruid, strerror(errno));
+	} else {
+		printUids();
+	}
+
+	printf("\nNow let's try to gain back our effective uid %d...\n", euid);
+	printf("Calling 'seteuid(%d)'...\n", euid);
+	if (seteuid(euid) < 0) {
+		fprintf(stderr, "Unable to seteuid(%d): %s\n", euid, strerror(errno));
+	}
+	printUids();
+
+	return EXIT_SUCCESS;
+}
--- a/apitue/sample-code/03/setuid.c
+++ b/apitue/sample-code/03/setuid.c
@ -0,0 +1,229 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* This trivial program illustrates the use of
+ * setuid(2) and seteuid(2).  After compiling,
+ * chmod(1) and chown(1) as needed to access a
+ * privileged resource (e.g. /etc/sudoers).
+ *
+ * Note: this example ignores group IDs.  See
+ * https://is.gd/l6pu5K for details on the
+ * order of dropping all privileges correctly.
+ *
+ * Example invocation:
+ * cc -Wall setuid.c
+ * sudo chown root a.out
+ * sudo chmod 4755 a.out
+ * ./a.out /etc/sudoers
+ *
+ * Note: after chowning, try to recompile.  Does
+ * your compiler overwrite a.out?  Why/why not?
+ *
+ * Note: setuid is not restricted to setuid-0.  Try
+ * with another user!
+ *
+ * mkdir -m 0700 /tmp/daemon
+ * touch /tmp/daemon/somefile
+ * chmod a+r /tmp/daemon/somefile
+ * sudo chown daemon /tmp/daemon
+ * sudo chown daemon a.out
+ * sudo chmod 4755 a.out
+ * ls -l a.out
+ * ls -l /tmp/daemon
+ * ls -ld /tmp/daemon
+ * ./a.out /tmp/daemon/somefile
+ * ./a.out /etc/sudoers
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define UNPRIVILEGED_UID 1
+
+char buf[BUFSIZ];
+
+uid_t ruid;
+uid_t euid;
+uid_t suid;
+
+void myseteuid(int);
+void printUids(const char *);
+
+/* We're using this wrapper function, because the behavior
+ * of seteuid(2) with respect to the saved-set-uid is inconsistent
+ * across platforms.  On e.g. NetBSD, the POSIX.1-2017 mandated
+ * behavior is not implemented; see the note in the manual page
+ * as well as in <unistd.h>. */
+void
+myseteuid(int myeuid) {
+	char *func = "seteuid(";
+#ifdef _POSIX_SAVED_IDS
+	if (seteuid(myeuid) == -1) {
+		fprintf(stderr, "Unable to seteuid(%d): %s\n", myeuid, strerror(errno));
+		exit(EXIT_FAILURE);
+		/* NOTREACHED */
+	}
+#else
+	if (setreuid(-1, myeuid) == -1) {
+		fprintf(stderr, "Unable to setreuid(-1, %d): %s\n", myeuid, strerror(errno));
+		exit(EXIT_FAILURE);
+		/* NOTREACHED */
+	}
+	func = "setreuid(-1, ";
+#endif
+	if (snprintf(buf, BUFSIZ, "After %s%d)", func, myeuid) < 0) {
+		fprintf(stderr, "Unable to snprintf: %s\n", strerror(errno));
+		exit(EXIT_FAILURE);
+		/* NOTREACHED */
+	}
+	printUids(buf);
+}
+
+/* On e.g. Linux, we can get the saved set-uid
+ * via getresuid(2); not all systems support
+ * this, however.  On those that do not,
+ * we use the suid value initialized at program
+ * startup.
+ */
+void
+printUids(const char *msg) {
+	ruid = getuid();
+	euid = geteuid();
+
+#ifdef _GNU_SOURCE
+	if (getresuid(&ruid, &euid, &suid) < 0) {
+		fprintf(stderr, "Unable to getresuid: %s\n", strerror(errno));
+		exit(EXIT_FAILURE);
+		/* NOTREACHED */
+	}
+#endif
+	printf("%s: ruid %d, euid %d, suid %d\n", msg, ruid, euid, suid);
+
+}
+
+int
+main(int argc, char **argv) {
+	int fd;
+
+	if (argc != 2) {
+		fprintf(stderr, "%s: Usage: %s filename\n", argv[0], argv[0]);
+		exit(EXIT_FAILURE);
+		/* NOTREACHED */
+	}
+
+	ruid = getuid();
+	euid = geteuid();
+	/* fake saved-setuid */
+	suid = geteuid();
+
+	printUids("Program start");
+
+	printf("We're privileged; let's set all UIDs to another account.\n");
+	myseteuid(UNPRIVILEGED_UID);
+
+	printf("We're unprivileged, but with the help of the saved set-uid, we can regain initial setuid (%d) privs.\n", suid);
+
+	printf("But let's drop them again via seteuid(%d)...\n", ruid);
+	myseteuid(ruid);
+
+	printf("Trying to open a privileged file...\n");
+	if ((fd = open(argv[1], O_RDONLY)) == -1) {
+		fprintf(stderr, "Unable to open %s: %s\n",
+					argv[1], strerror(errno));
+	}
+	/* We don't do anything with the file, we just demonstrated
+	 * that we were unable to open it. */
+	(void)close(fd);
+
+	printf("Ok, let's try with elevated privileges.\n");
+	myseteuid(suid);
+
+	if ((fd = open(argv[1], O_RDONLY)) == -1) {
+		fprintf(stderr, "Unable to open %s: %s\n",
+					argv[1], strerror(errno));
+		exit(EXIT_FAILURE);
+		/* NOTREACHED */
+	} else {
+		printf("Opening worked.\n");
+
+		/* Now we could do stuff with 'fd', if we were
+		 * so inclined.  We're not, though. */
+		(void)close(fd);
+	}
+
+	printf("Alright, we're done using our elevated privileges.  Let's drop them permanently.\n");
+	if (setuid(ruid) == -1) {
+		fprintf(stderr, "Unable to setuid: %s\n", strerror(errno));
+		exit(EXIT_FAILURE);
+		/* NOTREACHED */
+	}
+
+	if (snprintf(buf, BUFSIZ, "After setuid(%d)", ruid) < 0) {
+		fprintf(stderr, "Unable to snprintf: %s\n", strerror(errno));
+		exit(EXIT_FAILURE);
+		/* NOTREACHED */
+	}
+	printUids(buf);
+	printf("Now trying to gain elevated privileges again.\n");
+
+	/* Trying to gain elevated privileges again
+	 * should fail here, because setuid(2), called
+	 * above, is supposed to set the real and effective
+	 * uid as well as the saved set-user ID.
+	 *
+	 * However, the results are platform dependent,
+	 * based on whether or not the euid at
+	 * execution start was 0 or not.  See
+	 * https://is.gd/QVO35q for details.
+	 *
+	 * In practice, we observe that:
+	 * - NetBSD sets the saved set-user-ID in setuid(2)
+	 *   even for non-root
+	 * - OS X and Linux do NOT set the saved set-user-ID
+	 *   in setuid(2) IF the euid was non-zero
+	 */
+	if (seteuid(suid) != -1) {
+#ifdef _POSIX_SAVED_IDS
+		if (euid == 0) {
+			fprintf(stderr, "seteuid(%d) should not have succeeded!\n", euid);
+		}
+#endif
+	}
+
+	if (snprintf(buf, BUFSIZ, "After attempted seteuid(%d)", suid) < 0) {
+		fprintf(stderr, "Unable to snprintf: %s\n", strerror(errno));
+		exit(EXIT_FAILURE);
+		/* NOTREACHED */
+	}
+	printUids(buf);
+
+	printf("(We expect the following call to open(2) to fail if setuid was 0 initially.)\n");
+
+	if ((fd = open(argv[1], O_RDONLY)) == -1) {
+		fprintf(stderr, "Unable to open %s: %s\n",
+					argv[1], strerror(errno));
+	} else {
+		if (euid == 0) {
+			printf("Wait, what? This shouldn't have worked!\n");
+		}
+		(void)close(fd);
+	}
+
+	exit(EXIT_SUCCESS);
+}
--- a/apitue/sample-code/03/simple-ls-stat.c
+++ b/apitue/sample-code/03/simple-ls-stat.c
@ -0,0 +1,100 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * Variant of 'simple-ls' that illustrates the
+ * difference between stat(2) and lstat(2).
+ *
+ * Create a few files and symlink to different types
+ * of files to show.
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <dirent.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+char *
+getType(const struct stat sb) {
+	if (S_ISREG(sb.st_mode))
+		return "regular file";
+	else if (S_ISDIR(sb.st_mode))
+		return "directory";
+	else if (S_ISCHR(sb.st_mode))
+		return "character special";
+	else if (S_ISBLK(sb.st_mode))
+		return "block special";
+	else if (S_ISFIFO(sb.st_mode))
+		return "FIFO";
+	else if (S_ISLNK(sb.st_mode))
+		return "symbolic link";
+	else if (S_ISSOCK(sb.st_mode))
+		return "socket";
+	else
+		return "unknown";
+}
+
+int
+main(int argc, char **argv) {
+
+	DIR *dp;
+	struct dirent *dirp;
+
+	if (argc != 2) {
+		fprintf(stderr, "usage: %s dir_name\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	if ((dp = opendir(argv[1])) == NULL) {
+		fprintf(stderr, "can't open '%s'\n", argv[1]);
+		exit(EXIT_FAILURE);
+	}
+
+	if (chdir(argv[1]) == -1) {
+		fprintf(stderr, "can't chdir to '%s': %s\n", argv[1], strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	while ((dirp = readdir(dp)) != NULL) {
+		struct stat sb;
+		char *statType;
+
+		printf("%s: ", dirp->d_name);
+		if (stat(dirp->d_name, &sb) == -1) {
+			fprintf(stderr, "Can't stat %s: %s\n", dirp->d_name,
+						strerror(errno));
+			statType = "unknown";
+		} else {
+			statType = getType(sb);
+		}
+
+		if (lstat(dirp->d_name, &sb) == -1) {
+			fprintf(stderr,"Can't lstat %s: %s\n", dirp->d_name,
+						strerror(errno));
+			continue;
+		} else if (S_ISLNK(sb.st_mode)) {
+			printf("symlink to ");
+		}
+		printf("%s\n", statType);
+	}
+
+	(void)closedir(dp);
+	return EXIT_SUCCESS;
+}
--- a/apitue/sample-code/03/size.c
+++ b/apitue/sample-code/03/size.c
@ -0,0 +1,44 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* This simple program displays the stat data relevant to file sizes. */
+
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int
+main(int argc, char **argv) {
+	struct stat sb;
+
+	if (argc != 2) {
+		fprintf(stderr, "usage: %s file\n", argv[0]);
+		exit(1);
+	}
+
+	if (lstat(argv[1], &sb) == -1) {
+		fprintf(stderr, "Can't stat %s: %s\n", argv[1],
+						strerror(errno));
+		exit(1);
+	}
+
+	printf("st_size   : %d\n", (int)sb.st_size);
+	printf("st_blocks : %d\n", (int)sb.st_blocks);
+	printf("st_blksize: %d\n", (int)sb.st_blksize);
+	exit(0);
+}
--- a/apitue/sample-code/03/sls.c
+++ b/apitue/sample-code/03/sls.c
@ -0,0 +1,56 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * simple-ls.c
+ * Extremely low-power ls clone.
+ * ./simple-ls .
+ */
+
+#include <sys/types.h>
+#include <ufs/ufs/dir.h>
+
+#include <dirent.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+int
+main(int argc, char **argv) {
+
+	DIR *dp;
+	struct dirent *dirp;
+
+	if (argc != 2) {
+		fprintf(stderr, "usage: %s dir_name\n", argv[0]);
+		exit(1);
+	}
+
+	if ((dp = opendir(argv[1])) == NULL ) {
+		fprintf(stderr, "can't open '%s'\n", argv[1]);
+		exit(1);
+	}
+
+	while ((dirp = readdir(dp)) != NULL ) {
+		write(STDOUT_FILENO, dirp, sizeof(*dirp));
+		//printf("%s: %d %ld\n", dirp->d_name, dirp->d_reclen, UFS_DIRECTSIZ(dirp->d_namlen));
+		//printf("%ld\n", sizeof(*dirp));
+		//printf("%s: %d %ld\n", dirp->d_name, dirp->d_reclen, UFS_DIRECTSIZ(dirp->d_namlen));
+}
+
+	closedir(dp);
+	return(0);
+}
--- a/apitue/sample-code/03/still-simple-ls.c
+++ b/apitue/sample-code/03/still-simple-ls.c
@ -0,0 +1,114 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* This still very simple ls clone illustrates the use of the stat(2)
+ * family of functions to print out some information about the files in
+ * the given directory.
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <dirent.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+int
+main(int argc, char **argv) {
+
+	DIR *dp;
+	struct dirent *dirp;
+
+	if (argc != 2) {
+		fprintf(stderr, "usage: %s dir_name\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	if ((dp = opendir(argv[1])) == NULL ) {
+		fprintf(stderr, "can't open '%s': %s\n", argv[1], strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	if (chdir(argv[1]) == -1) {
+		fprintf(stderr, "can't chdir to '%s': %s\n", argv[1], strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	while ((dirp = readdir(dp)) != NULL ) {
+		struct stat sb;
+		if (stat(dirp->d_name, &sb) == -1) {
+			fprintf(stderr, "Can't stat %s: %s\n", dirp->d_name,
+						strerror(errno));
+
+			if (lstat(dirp->d_name, &sb) == -1) {
+				fprintf(stderr,"Can't stat %s: %s\n", dirp->d_name,
+						strerror(errno));
+				continue;
+			}
+		}
+
+		printf("%s: ", dirp->d_name);
+		if (S_ISREG(sb.st_mode))
+			printf("regular file");
+		else if (S_ISDIR(sb.st_mode))
+			printf("directory");
+		else if (S_ISCHR(sb.st_mode))
+			printf("character special");
+		else if (S_ISBLK(sb.st_mode))
+			printf("block special");
+		else if (S_ISFIFO(sb.st_mode))
+			printf("FIFO");
+		else if (S_ISLNK(sb.st_mode))
+			printf("symbolic link");
+		else if (S_ISSOCK(sb.st_mode))
+			printf("socket");
+		else
+			printf("unknown");
+
+		printf(" -- according to stat\n");
+
+		if (lstat(dirp->d_name, &sb) == -1) {
+			fprintf(stderr,"Can't stat %s: %s\n", dirp->d_name,
+						strerror(errno));
+			continue;
+		}
+
+		printf("%s: ", dirp->d_name);
+		if (S_ISREG(sb.st_mode))
+			printf("regular file");
+		else if (S_ISDIR(sb.st_mode))
+			printf("directory");
+		else if (S_ISCHR(sb.st_mode))
+			printf("character special");
+		else if (S_ISBLK(sb.st_mode))
+			printf("block special");
+		else if (S_ISFIFO(sb.st_mode))
+			printf("FIFO");
+		else if (S_ISLNK(sb.st_mode))
+			printf("symbolic link");
+		else if (S_ISSOCK(sb.st_mode))
+			printf("socket");
+		else
+			printf("unknown");
+
+		printf(" -- according to lstat\n\n");
+	}
+
+	closedir(dp);
+	exit(EXIT_SUCCESS);
+}
--- a/apitue/sample-code/03/tags
+++ b/apitue/sample-code/03/tags
@ -0,0 +1,14 @@
+Maccess	access.c	/^main(int argc, char **argv) {$/
+Mchmod	chmod.c	/^main() {$/
+Mdirentsize	direntsize.c	/^main(int argc, char **argv) {$/
+Msetuid	setuid.c	/^main(int argc, char **argv) {$/
+Msimple-ls	simple-ls.c	/^main(int argc, char **argv) {$/
+Msimple-ls-stat	simple-ls-stat.c	/^main(int argc, char **argv) {$/
+Msize	size.c	/^main(int argc, char **argv) {$/
+Msls	sls.c	/^main(int argc, char **argv) {$/
+Mstill-simple-ls	still-simple-ls.c	/^main(int argc, char **argv) {$/
+Mumask	umask.c	/^main() {$/
+getType	simple-ls-stat.c	/^getType(const struct stat sb) {$/
+myOpen	umask.c	/^myOpen(const char *path) {$/
+myseteuid	setuid.c	/^myseteuid(int myeuid) {$/
+printUids	setuid.c	/^printUids(const char *msg) {$/
--- a/apitue/sample-code/03/umask.c
+++ b/apitue/sample-code/03/umask.c
@ -0,0 +1,68 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* This simple program illustrates the use of a umask.
+ *
+ * First, set your umask to 022 and 'touch file'; the mode will be 0644.
+ *
+ * Next, run this program and find file1 with the same mode, but execute
+ * permissions added, file2 with the explicitly requested 0777 mode, and
+ * finally file3 with mode 0711, since we explicitly turned off other
+ * permissions.
+ *
+ * Observe that each time the flags passed to open(2) are identical.
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+void
+myOpen(const char *path) {
+	int fd;
+	if ((fd = open(path, O_CREAT | O_EXCL | O_WRONLY,
+				S_IRUSR | S_IWUSR | S_IXUSR |
+				S_IRGRP | S_IWGRP | S_IXGRP |
+				S_IROTH | S_IWOTH | S_IXOTH)) == -1) {
+		fprintf(stderr, "Unable to create %s: %s\n",
+				path, strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+	(void)close(fd);
+}
+
+int
+main() {
+	/* current umask from your shell will apply to 'file1' */
+	myOpen("file1");
+
+	umask(0);
+	/* turning all bits off means we will allow
+	 * all the bits specified in open(2) */
+	myOpen("file2");
+
+	umask(S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
+	/* turning group/other permissions off in the
+	 * umask means they won't be set in open(2) */
+	myOpen("file3");
+
+	return EXIT_SUCCESS;
+}
--- a/apitue/sample-code/04/cd.c
+++ b/apitue/sample-code/04/cd.c
@ -0,0 +1,49 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* This program illustrates the uselessness of an external cd(1) command,
+ * as required by POSIX.1; note that many Unix versions don't bother
+ * implementing /usr/bin/cd anymore, but FreeBSD and Mac OS X, for
+ * example, still provide it via a generic shell builtin wrapper:
+ * http://www.freebsd.org/cgi/cvsweb.cgi/~checkout~/src/usr.bin/alias/generic.sh?rev=HEAD;content-type=text%2Fplain
+ */
+#include <sys/param.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+int
+main(int argc, char **argv) {
+	char buf[MAXPATHLEN];
+
+	if (argc != 2) {
+		fprintf(stderr, "%s: need a directory!\n", argv[0]);
+		return(EXIT_FAILURE);
+	}
+
+	if (chdir(argv[1]) == -1) {
+		fprintf(stderr, "%s: unable to chdir to %s: %s\n", argv[0],
+						argv[1], strerror(errno));
+		return(EXIT_FAILURE);
+	}
+
+	printf("Ok, cwd is now: %s\n", getcwd(buf, MAXPATHLEN));
+
+	exit(EXIT_SUCCESS);
+}
--- a/apitue/sample-code/04/getpw.c
+++ b/apitue/sample-code/04/getpw.c
@ -0,0 +1,139 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * https://stevens.netmeister.org/631/
+ */
+
+
+/* This program illustrates the use of the various
+ * 'getpw*' functions.  If given a username or a uid,
+ * it will attempt to print the information for the
+ * given user, otherwise, it will iterate over all
+ * entries and print them out in /etc/passwd format.
+ *
+ * ./a.out 0
+ * ./a.out root
+ * ./a.out
+ *
+ * Btw, what happens when you run this program as root?
+ */
+
+/* We pulled in some code from id(1):
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+#include <assert.h>
+#include <err.h>
+#include <errno.h>
+#include <limits.h>
+#include <pwd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+struct passwd *who(char *);
+
+void printAllEntries(void);
+void printOneStruct(const struct passwd *pw);
+
+struct passwd *
+who(char *u)
+{
+	struct passwd *pw;
+	long id;
+	char *ep;
+
+	/* Translate user argument into a pw pointer.
+	 * First, try to get it as specified.  If that
+	 * fails, try it as a number. */
+	if ((pw = getpwnam(u)) != NULL) {
+		return pw;
+	}
+
+	id = strtol(u, &ep, 10);
+	if (*u && !*ep && (pw = getpwuid(id))) {
+		return pw;
+	}
+
+	errx(EXIT_FAILURE, "%s: No such user", u);
+	/* NOTREACHED */
+	return NULL;
+}
+
+void
+printAllEntries(void) {
+	struct passwd *pw;
+	errno = 0;
+	while ((pw = getpwent()) != NULL) {
+		printOneStruct(pw);
+	}
+	if (errno) {
+		fprintf(stderr, "%s: Unable to call getpwent(3): %s\n",
+				getprogname(), strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	/* We're exiting after this call, so the
+	 * kernel would close the password database
+	 * for us, but since we want to develop
+	 * good coding habits, we're calling
+	 * endpwent(3) here just like we'd call
+	 * close(2) in other programs. */
+	endpwent();
+}
+
+void
+printOneStruct(const struct passwd *pw) {
+	assert(pw);
+	printf("%s:%s:%d:%d:%s:%s:%s\n", pw->pw_name, pw->pw_passwd,
+					pw->pw_uid, pw->pw_gid,
+					pw->pw_gecos, pw->pw_dir,
+					pw->pw_shell);
+}
+
+int
+main(int argc, char ** argv)
+{
+	(void)setprogname(argv[0]);
+
+	if (argc > 2) {
+		fprintf(stderr, "Usage: %s [name|uid]\n", getprogname());
+		exit(EXIT_FAILURE);
+	}
+
+	if (argc == 2) {
+		printOneStruct(who(argv[1]));
+	} else {
+		printAllEntries();
+	}
+
+	return EXIT_SUCCESS;
+}
--- a/apitue/sample-code/04/groups.c
+++ b/apitue/sample-code/04/groups.c
@ -0,0 +1,149 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ * 
+ * https://stevens.netmeister.org/631/
+ */
+
+/* This program is a trivial version of the 'groups'
+ * command.
+ */
+
+/* We pulled in some code from id(1):
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+#include <assert.h>
+#include <err.h>
+#include <errno.h>
+#include <grp.h>
+#include <limits.h>
+#include <pwd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+struct passwd *who(char *);
+
+struct passwd *
+who(char *u)
+{
+	struct passwd *pw;
+	long id;
+	char *ep;
+
+	/* Translate user argument into a pw pointer.
+	 * First, try to get it as specified.  If that
+	 * fails, try it as a number. */
+	if ((pw = getpwnam(u)) != NULL) {
+		return pw;
+	}
+
+	id = strtol(u, &ep, 10);
+	if (*u && !*ep && (pw = getpwuid(id))) {
+		return pw;
+	}
+
+	errx(EXIT_FAILURE, "%s: No such user", u);
+	/* NOTREACHED */
+	return NULL;
+}
+
+int
+main(int argc, char ** argv) {
+	gid_t *groups, *glist;
+	int cnt, maxgroups, ngroups;
+	struct passwd *pw;
+	struct group *gr;
+
+	(void)setprogname(argv[0]);
+
+	if (argc > 2) {
+		(void)fprintf(stderr, "Usage: %s [name|uid]\n", getprogname());
+		exit(EXIT_FAILURE);
+	}
+
+	pw = argv[1] ? who(argv[1]) : NULL;
+
+	if ((maxgroups = sysconf(_SC_NGROUPS_MAX)) < 0) {
+		err(EXIT_FAILURE, "unable to call sysconf");
+		/* NOTREACHED */
+	}
+	if ((groups = malloc((maxgroups + 1) * sizeof(gid_t))) == NULL) {
+		err(EXIT_FAILURE, "unable to malloc");
+		/* NOTREACHED */
+	}
+	glist = groups;
+
+	if (pw) {
+		ngroups = maxgroups;
+		if (getgrouplist(pw->pw_name, pw->pw_gid, glist, &ngroups)
+				== -1) {
+			if ((glist = malloc(ngroups * sizeof(gid_t))) == NULL) {
+				err(EXIT_FAILURE, "unable to malloc");
+				/* NOTREACHED */
+			}
+			(void)getgrouplist(pw->pw_name, pw->pw_gid, glist,
+					&ngroups);
+		}
+	} else {
+		glist[0] = getgid();
+		if ((ngroups = getgroups(maxgroups, glist + 1) + 1) == 0) {
+			err(EXIT_FAILURE, "unable to getgroups");
+			/* NOTREACHED */
+		}
+	}
+
+	for (cnt = 0; cnt < ngroups; ++cnt) {
+		if (cnt && glist[cnt] == glist[0]) {
+			continue;
+		}
+		if ((gr = getgrgid(glist[cnt])) == NULL) {
+			(void)fprintf(stderr, "%s: unable to getgrgid(%u): %s\n",
+					getprogname(), glist[cnt], strerror(errno));
+		} else {
+			(void)printf("%s", gr->gr_name);
+			if (cnt < ngroups) {
+				(void)printf(" ");
+			}
+		}
+	}
+	if (cnt) {
+		(void)printf("\n");
+	}
+
+	if (glist != groups) {
+		(void)free(glist);
+	}
+	(void)free(groups);
+
+	return EXIT_SUCCESS;
+}
--- a/apitue/sample-code/04/lns.c
+++ b/apitue/sample-code/04/lns.c
@ -0,0 +1,38 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* The world's most trivial 'ln -s', in a way. */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+int
+main(int argc, char **argv) {
+	if (argc != 3) {
+		fprintf(stderr, "Usage: %s source target\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	if (symlink(argv[1], argv[2]) < 0) {
+		fprintf(stderr, "Unable to symlink '%s' to '%s': %s\n",
+				argv[2], argv[1], strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	return EXIT_SUCCESS;
+}
--- a/apitue/sample-code/04/rename.c
+++ b/apitue/sample-code/04/rename.c
@ -0,0 +1,38 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* The world's most trivial 'mv', in a way. */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+int
+main(int argc, char **argv) {
+	if (argc != 3) {
+		fprintf(stderr, "Usage: %s from to\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	if (rename(argv[1], argv[2]) < 0) {
+		fprintf(stderr, "Unable to rename '%s' to '%s': %s\n",
+				argv[1], argv[2], strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	return EXIT_SUCCESS;
+}
--- a/apitue/sample-code/04/sizeof.c
+++ b/apitue/sample-code/04/sizeof.c
@ -0,0 +1,60 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* Students frequently think that the result of 'sizeof'
+ * is equivalent to that of strlen(3).  Let's illustrate
+ * the differences. */
+
+#include <errno.h>
+#include <libgen.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int main() {
+
+	printf("int: %ld\n", sizeof(int));
+
+	char buf[BUFSIZ];
+	printf("Fixed buffer, size known at compile time: \"buf[%d]\"\n", BUFSIZ);
+	printf("strlen: %lu - sizeof: %lu\n\n", strlen(buf), sizeof buf);
+
+	char buf2[2] = { 'a' };
+	printf("Fixed-size, initialized buffer: \"buf[2] = { 'a' }\"\n");
+	printf("strlen: %lu - sizeof: %lu\n\n", strlen(buf2), sizeof buf2);
+
+	char *s = "abcde";
+	printf("A pointer: 'char *s = \"abcde\"'\n");
+	printf("strlen: %lu - sizeof: %lu\n\n", strlen(s), sizeof s);
+
+	char buf3[] = "abcde";
+	printf("Another initialized buffer, implicitly sized: 'buf3[] =\"abcde\"'\n");
+	printf("strlen: %lu - sizeof: %lu\n\n", strlen(buf3), sizeof buf3);
+
+	if ((s = malloc(BUFSIZ)) == NULL) {
+		fprintf(stderr, "Unable to allocate memory: %s\n",
+				strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	printf("A pointer to malloc(3)'d memory:\n");
+	printf("strlen: %lu - sizeof: %lu\n\n", strlen(s), sizeof s);
+
+	(void)strncat(s, "0123456789", BUFSIZ);
+	printf("After strncat(3)ing \"0123456789\" to 's':\n");
+	printf("strlen: %lu - sizeof: %lu\n\n", strlen(s), sizeof s);
+
+	return EXIT_SUCCESS;
+}
--- a/apitue/sample-code/04/time.c
+++ b/apitue/sample-code/04/time.c
@ -0,0 +1,84 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+#include <err.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+/* ISO 8601 format is "YYYY-MM-DDTHH:MM:SSZ" */
+#define ISO8601_LENGTH 20 + 1 /* +1 for NULL */
+
+int
+main() {
+	time_t t;
+	struct timeval tv;
+	struct timespec ts;
+	struct tm *tm;
+
+	char buf[ISO8601_LENGTH];
+
+	if ((t = time(NULL)) < 0) {
+		err(EXIT_FAILURE, "unable to call time()");
+		/* NOTREACHED */
+	}
+	(void)printf("time(3) says:          %ld\n", t);
+
+	if (gettimeofday(&tv, NULL) < 0) {
+		err(EXIT_FAILURE, "unable to gettimeofday()");
+		/* NOTREACHED */
+	}
+	(void)printf("gettimeofday(2) says:  %ld.%d\n", tv.tv_sec, tv.tv_usec);
+
+	if (clock_gettime(CLOCK_REALTIME, &ts) < 0) {
+		err(EXIT_FAILURE, "unable to call clock_gettime(2)");
+		/* NOTREACHED */
+	}
+	(void)printf("clock_gettime(2) says: %ld.%ld\n\n", ts.tv_sec, ts.tv_nsec);
+
+	if ((tm = gmtime(&t)) == NULL) {
+		err(EXIT_FAILURE, "unable to call gmtime()");
+		/* NOTREACHED */
+	}
+	(void)printf("asctime(3) says:       %s", asctime(tm));
+
+	if ((tm = localtime(&t)) == NULL) {
+		err(EXIT_FAILURE, "unable to call gmtime()");
+		/* NOTREACHED */
+	}
+	(void)printf("localtime is:          %s", asctime(tm));
+
+	tm->tm_sec = 0;
+	tm->tm_min = 0;
+	tm->tm_hour = 0;
+	tm->tm_mday = 1;
+	tm->tm_mon = 0;
+	tm->tm_year = 70;
+	tm->tm_isdst = 0;
+
+	if ((t = mktime(tm)) < 0) {
+		err(EXIT_FAILURE, "unable to call mktime()");
+		/* NOTREACHED */
+	}
+	(void)printf("epoch date is:         %s", ctime(&t));
+
+	if ((strftime(buf, ISO8601_LENGTH, "%Y-%m-%dT%H:%M:%SZ", tm)) == 0) {
+		err(EXIT_FAILURE, "strftime failed");
+		/* NOTREACHED */
+	}
+	(void)printf("ISO8601 formatted:     %s\n", buf);
+
+	return EXIT_SUCCESS;
+}
--- a/apitue/sample-code/04/wait-unlink.c
+++ b/apitue/sample-code/04/wait-unlink.c
@ -0,0 +1,126 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* This simple program is used to illustrate that the OS does not free up
+ * the disk space used by a file immediately after a call to unlink(2),
+ * but only after the last process with an open handle has terminated.
+ *
+ * Run like this:
+ *
+ * $ cc -Wall wait-unlink.c
+ * $ ./a.out
+ */
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+void
+runDf() {
+	printf("\nAvailable space is now:\n");
+	if (system("df .") != 0) {
+		perror("unable to run df(1)");
+		exit(EXIT_FAILURE);
+	}
+}
+
+int
+main() {
+	int fd;
+
+	/* "/tmp" is a memory file system on our
+	 * reference platform, so let's use a separate
+	 * temporary directory backed by a "normal"
+	 * filesystem. */
+	if (chdir("/var/tmp") == -1) {
+		perror("unable to cd to /var/tmp");
+		exit(EXIT_FAILURE);
+	}
+
+	runDf();
+
+	/* Hit return to continue. */
+	(void)getchar();
+
+	printf("Creating a 500M file...\n");
+	if (system("dd if=/dev/zero of=foo bs=1024k count=500 >/dev/null") != 0) {
+		perror("unable to dd a new file");
+		exit(EXIT_FAILURE);
+	}
+
+	runDf();
+
+	(void)getchar();
+	printf("\nLinking 'bar' to 'foo'...\n\n");
+	if (link("foo", "bar") == -1) {
+		perror("unable to create a second hard link");
+		exit(EXIT_FAILURE);
+	}
+
+	if (system("ls -li foo bar") != 0) {
+		perror("unable to run ls(1)");
+		exit(EXIT_FAILURE);
+	}
+
+	runDf();
+
+	(void)getchar();
+	if ((fd = open("foo", O_RDWR)) < 0) {
+		perror("can't open file");
+		exit(EXIT_FAILURE);
+	}
+	printf("\nOpened 'foo' on fd#%d.\n", fd);
+
+	(void)getchar();
+	if (unlink("foo") < 0) {
+		perror("error unlinking");
+		exit(EXIT_FAILURE);
+	}
+
+	printf("\nOk, foo unlinked.\n");
+	printf("Disk space not free'd since 'bar' still exists...\n");
+	/* We expect system(3) to fail here, since 'foo' no longer exists. */
+	(void)system("ls -li foo bar");
+
+	runDf();
+
+	(void)getchar();
+	printf("\nOk, now unlinking 'bar'...\n");
+	if (unlink("bar") < 0) {
+		perror("error unlinking");
+		exit(EXIT_FAILURE);
+	}
+
+	printf("\nOk, bar unlinked.\n");
+	(void)getchar();
+
+	printf("Disk space not free'd since I still have fd#%d open...\n", fd);
+	printf("\nRunning 'ls -li foo bar':\n");
+	(void)system("ls -li foo bar");
+
+	runDf();
+
+	(void)getchar();
+	printf("Now closing fd#%d...\n", fd);
+	/* Closing the file descriptor after having
+	 * unlinked all references to the 500M file
+	 * finally frees the disk space. */
+	(void)close(fd);
+	printf("\n...and done.  Disk space is freed now.\n");
+
+	runDf();
+
+	exit(EXIT_SUCCESS);
+}
--- a/apitue/sample-code/05/Makefile
+++ b/apitue/sample-code/05/Makefile
@ -0,0 +1,58 @@
+TARGET	=	slides
+
+LATEX	=	latex
+DVIPS	=	dvips -o
+PS2PDF	=	ps2pdf
+PDFTOTEXT=	pdftotext
+
+FIGURES=	pics/terminal.eps		\
+		pics/ide.eps			\
+		pics/compiler.eps		\
+		pics/ls.eps			\
+		pics/ls-changed1.eps		\
+		pics/ls-changed2.eps		\
+		pics/ls-changed3.eps		\
+		pics/ls-changed4.eps		\
+		pics/compiler_monster.eps	\
+		pics/makerbot.eps		\
+		pics/debugging.eps		\
+		pics/vim.eps
+
+.SUFFIXES: .tex .dvi .ps .pdf .fig .eps .png .dot .jpg .gif
+
+all:	$(FIGURES) $(TARGET).dvi
+
+slides:
+
+.tex.dvi:
+	$(LATEX) $<
+	$(LATEX) $<
+
+.jpg.eps:
+	convert $< $@
+
+.gif.eps:
+	convert $< $@
+
+.png.eps:
+	pngtopnm $< | pnmtops > $@
+
+.dot.eps:
+	dot -Tpng $< | pngtopnm | pnmtops > $@
+
+.fig.eps:
+	fig2dev -L eps $< > $@
+
+ps:	$(TARGET).dvi $(TARGET).ps
+
+.dvi.ps:
+	$(DVIPS) $@ $<
+
+pdf:  $(FIGURES) $(TARGET).dvi $(TARGET).ps $(TARGET).pdf
+
+.ps.pdf:
+	$(PS2PDF) $< $@
+
+clean:
+	rm -f **.bbl *.blg *.log *.aux *.dvi *.ps *.pdf *.toc *.bak *.lof ${FIGURES} *.out
+	rm -fr $(TARGET)/
--- a/apitue/sample-code/05/compilechain/Makefile
+++ b/apitue/sample-code/05/compilechain/Makefile
@ -0,0 +1,30 @@
+all: a.out
+
+cpp: preprocess
+
+preprocess: hello.i
+
+hello.i: hello.c
+	cpp -P $> >$@
+
+compile: hello.s
+
+hello.s: hello.i
+	cc -S $> -o $@
+
+assemble: hello.o
+
+hello.o: hello.s
+	as -o $@ $<
+
+link:	a.out
+
+a.out: hello.o
+	ld -dynamic-linker /usr/libexec/ld.elf_so /usr/lib/crt0.o	\
+		/usr/lib/crti.o /usr/lib/crtbegin.o hello.o 		\
+		-lc /usr/lib/crtend.o /usr/lib/crtn.o
+
+
+
+clean:
+	rm -f hello.i hello.o hello.s a.out
--- a/apitue/sample-code/05/compilechain/a.out
+++ b/apitue/sample-code/05/compilechain/a.out
--- a/apitue/sample-code/05/compilechain/hello.c
+++ b/apitue/sample-code/05/compilechain/hello.c
@ -0,0 +1,54 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* A very simple program to illustrate the different stages in the
+ * compilation process.  First, use cpp(1) to pre-process the file; repeat
+ * with FOOD defined to a different value.  Compare output, illustrate
+ * that code is pulled in by the preprocessor and macros expanded.  Then,
+ * compile hello.i to hello.s and show the resulting assembly output
+ * before using as(1) to generate object code.  Use objdump(1) (or
+ * similar) to disassemble the object code.  Finally, use ld(1) to create
+ * an executable.
+ *
+ * To illustrate compiler optimization, compile with
+ * '-O0 -S' and once with '-O4 -S' and compare the
+ * output.  You should notice that the calls to func1
+ * and func2 are eliminated when optimization is
+ * turned on.
+ *
+ * The file 'dump' includes the traced output of the compiler invocation.
+ * Show the different stages again.
+ */
+#include <stdio.h>
+
+#ifndef FOOD
+#define FOOD "Avocado"
+#endif
+
+void
+func2(void) {
+	printf("%s: great on anything.\n", FOOD);
+}
+
+void
+func1(void) {
+	func2();
+}
+
+int
+main() {
+	func1();
+	return 0;
+}
--- a/apitue/sample-code/05/compilechain/hello.i
+++ b/apitue/sample-code/05/compilechain/hello.i
@ -0,0 +1,342 @@
+static __inline long long __zeroll(void) { return 0; }
+static __inline unsigned long long __zeroull(void) { return 0; }
+typedef signed char __int8_t;
+typedef unsigned char __uint8_t;
+typedef short int __int16_t;
+typedef short unsigned int __uint16_t;
+typedef int __int32_t;
+typedef unsigned int __uint32_t;
+typedef long int __int64_t;
+typedef long unsigned int __uint64_t;
+typedef long int __intptr_t;
+typedef long unsigned int __uintptr_t;
+typedef char * __caddr_t;
+typedef __uint32_t __gid_t;
+typedef __uint32_t __in_addr_t;
+typedef __uint16_t __in_port_t;
+typedef __uint32_t __mode_t;
+typedef __int64_t __off_t;
+typedef __int32_t __pid_t;
+typedef __uint8_t __sa_family_t;
+typedef unsigned int __socklen_t;
+typedef __uint32_t __uid_t;
+typedef __uint64_t __fsblkcnt_t;
+typedef __uint64_t __fsfilcnt_t;
+struct __tag_wctrans_t;
+typedef struct __tag_wctrans_t *__wctrans_t;
+struct __tag_wctype_t;
+typedef struct __tag_wctype_t *__wctype_t;
+typedef union {
+ __int64_t __mbstateL;
+ char __mbstate8[128];
+} __mbstate_t;
+typedef __builtin_va_list __va_list;
+typedef long unsigned int size_t;
+typedef long int ssize_t;
+typedef struct __sfpos {
+ __off_t _pos;
+ __mbstate_t _mbstate_in, _mbstate_out;
+} fpos_t;
+struct __sbuf {
+ unsigned char *_base;
+ int _size;
+};
+typedef struct __sFILE {
+ unsigned char *_p;
+ int _r;
+ int _w;
+ unsigned short _flags;
+ short _file;
+ struct __sbuf _bf;
+ int _lbfsize;
+ void *_cookie;
+ int (*_close)(void *);
+ ssize_t (*_read) (void *, void *, size_t);
+ __off_t (*_seek) (void *, __off_t, int);
+ ssize_t (*_write)(void *, const void *, size_t);
+ struct __sbuf _ext;
+ unsigned char *_up;
+ int _ur;
+ unsigned char _ubuf[3];
+ unsigned char _nbuf[1];
+ int (*_flush)(void *);
+ char _lb_unused[sizeof(struct __sbuf) - sizeof(int (*)(void *))];
+ int _blksize;
+ __off_t _offset;
+} FILE;
+
+#pragma GCC visibility push(default)
+
+extern FILE __sF[3];
+
+#pragma GCC visibility pop
+
+
+#pragma GCC visibility push(default)
+
+void clearerr(FILE *);
+int fclose(FILE *);
+int feof(FILE *);
+int ferror(FILE *);
+int fflush(FILE *);
+int fgetc(FILE *);
+char *fgets(char * restrict, int, FILE * restrict);
+FILE *fopen(const char * restrict , const char * restrict);
+int fprintf(FILE * restrict, const char * restrict, ...)
+  __attribute__((__format__ (__printf__, 2, 3)));
+int fputc(int, FILE *);
+int fputs(const char * restrict, FILE * restrict);
+size_t fread(void * restrict, size_t, size_t, FILE * restrict);
+FILE *freopen(const char * restrict, const char * restrict,
+     FILE * restrict);
+int fscanf(FILE * restrict, const char * restrict, ...)
+  __attribute__((__format__ (__scanf__, 2, 3)));
+int fseek(FILE *, long, int);
+long ftell(FILE *);
+size_t fwrite(const void * restrict, size_t, size_t, FILE * restrict);
+int getc(FILE *);
+int getchar(void);
+void perror(const char *);
+int printf(const char * restrict, ...)
+  __attribute__((__format__ (__printf__, 1, 2)));
+int putc(int, FILE *);
+int putchar(int);
+int puts(const char *);
+int remove(const char *);
+void rewind(FILE *);
+int scanf(const char * restrict, ...)
+  __attribute__((__format__ (__scanf__, 1, 2)));
+void setbuf(FILE * restrict, char * restrict);
+int setvbuf(FILE * restrict, char * restrict, int, size_t);
+int sscanf(const char * restrict, const char * restrict, ...)
+  __attribute__((__format__ (__scanf__, 2, 3)));
+FILE *tmpfile(void);
+int ungetc(int, FILE *);
+int vfprintf(FILE * restrict, const char * restrict, __va_list)
+  __attribute__((__format__ (__printf__, 2, 0)));
+int vprintf(const char * restrict, __va_list)
+  __attribute__((__format__ (__printf__, 1, 0)));
+char *gets(char *);
+int sprintf(char * restrict, const char * restrict, ...)
+  __attribute__((__format__ (__printf__, 2, 3)));
+char *tmpnam(char *);
+int vsprintf(char * restrict, const char * restrict,
+    __va_list)
+  __attribute__((__format__ (__printf__, 2, 0)));
+int rename (const char *, const char *);
+
+#pragma GCC visibility pop
+
+int fgetpos(FILE * restrict, fpos_t * restrict) __asm("__fgetpos50");
+int fsetpos(FILE *, const fpos_t *) __asm("__fsetpos50");
+
+#pragma GCC visibility push(default)
+
+char *ctermid(char *);
+char *cuserid(char *);
+FILE *fdopen(int, const char *);
+int fileno(FILE *);
+
+#pragma GCC visibility pop
+
+
+#pragma GCC visibility push(default)
+
+void flockfile(FILE *);
+int ftrylockfile(FILE *);
+void funlockfile(FILE *);
+int getc_unlocked(FILE *);
+int getchar_unlocked(void);
+int putc_unlocked(int, FILE *);
+int putchar_unlocked(int);
+
+#pragma GCC visibility pop
+
+
+#pragma GCC visibility push(default)
+
+int pclose(FILE *);
+FILE *popen(const char *, const char *);
+
+#pragma GCC visibility pop
+
+
+#pragma GCC visibility push(default)
+
+FILE *popenve(const char *, char *const *, char *const *, const char *);
+
+#pragma GCC visibility pop
+
+
+#pragma GCC visibility push(default)
+
+int snprintf(char * restrict, size_t, const char * restrict, ...)
+  __attribute__((__format__ (__printf__, 3, 4)));
+int vsnprintf(char * restrict, size_t, const char * restrict,
+     __va_list)
+  __attribute__((__format__ (__printf__, 3, 0)));
+
+#pragma GCC visibility pop
+
+
+#pragma GCC visibility push(default)
+
+int getw(FILE *);
+int putw(int, FILE *);
+char *tempnam(const char *, const char *);
+
+#pragma GCC visibility pop
+
+typedef __off_t off_t;
+
+#pragma GCC visibility push(default)
+
+int fseeko(FILE *, __off_t, int);
+__off_t ftello(FILE *);
+
+#pragma GCC visibility pop
+
+
+#pragma GCC visibility push(default)
+
+int vscanf(const char * restrict, __va_list)
+  __attribute__((__format__ (__scanf__, 1, 0)));
+int vfscanf(FILE * restrict, const char * restrict, __va_list)
+  __attribute__((__format__ (__scanf__, 2, 0)));
+int vsscanf(const char * restrict, const char * restrict,
+    __va_list)
+    __attribute__((__format__ (__scanf__, 2, 0)));
+
+#pragma GCC visibility pop
+
+
+#pragma GCC visibility push(default)
+
+int asprintf(char ** restrict, const char * restrict, ...)
+  __attribute__((__format__ (__printf__, 2, 3)));
+char *fgetln(FILE * restrict, size_t * restrict);
+char *fparseln(FILE *, size_t *, size_t *, const char[3], int);
+int fpurge(FILE *);
+void setbuffer(FILE *, char *, int);
+int setlinebuf(FILE *);
+int vasprintf(char ** restrict, const char * restrict,
+    __va_list)
+  __attribute__((__format__ (__printf__, 2, 0)));
+const char *fmtcheck(const char *, const char *)
+  __attribute__((__format_arg__ (2)));
+
+#pragma GCC visibility pop
+
+
+#pragma GCC visibility push(default)
+
+FILE *funopen(const void *,
+    int (*)(void *, char *, int),
+    int (*)(void *, const char *, int),
+    __off_t (*)(void *, __off_t, int),
+    int (*)(void *));
+FILE *funopen2(const void *,
+    ssize_t (*)(void *, void *, size_t),
+    ssize_t (*)(void *, const void *, size_t),
+    __off_t (*)(void *, __off_t, int),
+    int (*)(void *),
+    int (*)(void *));
+
+#pragma GCC visibility pop
+
+
+#pragma GCC visibility push(default)
+
+int __srget(FILE *);
+int __swbuf(int, FILE *);
+
+#pragma GCC visibility pop
+
+static __inline int __sputc(int _c, FILE *_p) {
+ if (--_p->_w >= 0 || (_p->_w >= _p->_lbfsize && (char)_c != '\n'))
+  return *_p->_p++ = (unsigned char)_c;
+ else
+  return __swbuf(_c, _p);
+}
+
+#pragma GCC visibility push(default)
+
+int vdprintf(int, const char * restrict, __va_list)
+  __attribute__((__format__ (__printf__, 2, 0)));
+int dprintf(int, const char * restrict, ...)
+  __attribute__((__format__ (__printf__, 2, 3)));
+
+#pragma GCC visibility pop
+
+
+#pragma GCC visibility push(default)
+
+FILE *fmemopen(void * restrict, size_t, const char * restrict);
+FILE *open_memstream(char **, size_t *);
+ssize_t getdelim(char ** restrict, size_t * restrict, int,
+     FILE * restrict);
+ssize_t getline(char ** restrict, size_t * restrict, FILE * restrict);
+
+#pragma GCC visibility pop
+
+typedef struct _locale *locale_t;
+
+#pragma GCC visibility push(default)
+
+int fprintf_l(FILE * restrict, locale_t, const char * restrict, ...)
+  __attribute__((__format__ (__printf__, 3, 4)));
+int vfprintf_l(FILE * restrict, locale_t, const char * restrict,
+  __va_list) __attribute__((__format__ (__printf__, 3, 0)));
+int printf_l(locale_t, const char * restrict, ...)
+  __attribute__((__format__ (__printf__, 2, 3)));
+int vprintf_l(locale_t, const char * restrict, __va_list)
+  __attribute__((__format__ (__printf__, 2, 0)));
+int asprintf_l(char ** restrict, locale_t, const char * restrict, ...)
+  __attribute__((__format__ (__printf__, 3, 4)));
+int vasprintf_l(char ** restrict, locale_t, const char * restrict,
+    __va_list)
+  __attribute__((__format__ (__printf__, 3, 0)));
+int vdprintf_l(int, locale_t, const char * restrict, __va_list)
+  __attribute__((__format__ (__printf__, 3, 0)));
+int dprintf_l(int, locale_t, const char * restrict, ...)
+  __attribute__((__format__ (__printf__, 3, 4)));
+int snprintf_l(char * restrict, size_t, locale_t,
+      const char * restrict, ...) __attribute__((__format__ (__printf__, 4, 5)));
+int vsnprintf_l(char * restrict, size_t, locale_t,
+       const char * restrict, __va_list) __attribute__((__format__ (__printf__, 4, 0)));
+int sprintf_l(char * restrict, locale_t, const char * restrict, ...)
+     __attribute__((__format__ (__printf__, 3, 4)));
+int vsprintf_l(char * restrict, locale_t, const char * restrict,
+      __va_list) __attribute__((__format__ (__printf__, 3, 0)));
+int fscanf_l(FILE * restrict, locale_t, const char * restrict, ...)
+    __attribute__((__format__ (__scanf__, 3, 4)));
+int scanf_l(locale_t, const char * restrict, ...)
+    __attribute__((__format__ (__scanf__, 2, 3)));
+int sscanf_l(const char * restrict, locale_t,
+    const char * restrict, ...) __attribute__((__format__ (__scanf__, 3, 4)));
+int vscanf_l(locale_t, const char * restrict, __va_list)
+    __attribute__((__format__ (__scanf__, 2, 0)));
+int vfscanf_l(FILE * restrict, locale_t, const char * restrict,
+    __va_list) __attribute__((__format__ (__scanf__, 3, 0)));
+int vsscanf_l(const char * restrict, locale_t, const char * restrict,
+    __va_list) __attribute__((__format__ (__scanf__, 3, 0)));
+int snprintf_ss(char *restrict, size_t, const char * restrict, ...)
+    __attribute__((__format__ (__printf__, 3, 4)));
+int vsnprintf_ss(char *restrict, size_t, const char * restrict, __va_list)
+    __attribute__((__format__ (__printf__, 3, 0)));
+
+#pragma GCC visibility pop
+
+void
+func2(void) {
+ printf("%s: great on anything.\n", "avocado");
+}
+void
+func1(void) {
+ func2();
+}
+int
+main() {
+ func1();
+ return 0;
+}
--- a/apitue/sample-code/05/compilechain/hello.o
+++ b/apitue/sample-code/05/compilechain/hello.o
--- a/apitue/sample-code/05/compilechain/hello.s
+++ b/apitue/sample-code/05/compilechain/hello.s
@ -0,0 +1,66 @@
+	.file	"hello.i"
+	.text
+	.section	.rodata
+.LC0:
+	.string	"avocado"
+.LC1:
+	.string	"%s: great on anything.\n"
+	.text
+	.globl	func2
+	.type	func2, @function
+func2:
+.LFB3:
+	.cfi_startproc
+	pushq	%rbp
+	.cfi_def_cfa_offset 16
+	.cfi_offset 6, -16
+	movq	%rsp, %rbp
+	.cfi_def_cfa_register 6
+	movl	$.LC0, %esi
+	movl	$.LC1, %edi
+	movl	$0, %eax
+	call	printf
+	nop
+	popq	%rbp
+	.cfi_def_cfa 7, 8
+	ret
+	.cfi_endproc
+.LFE3:
+	.size	func2, .-func2
+	.globl	func1
+	.type	func1, @function
+func1:
+.LFB4:
+	.cfi_startproc
+	pushq	%rbp
+	.cfi_def_cfa_offset 16
+	.cfi_offset 6, -16
+	movq	%rsp, %rbp
+	.cfi_def_cfa_register 6
+	call	func2
+	nop
+	popq	%rbp
+	.cfi_def_cfa 7, 8
+	ret
+	.cfi_endproc
+.LFE4:
+	.size	func1, .-func1
+	.globl	main
+	.type	main, @function
+main:
+.LFB5:
+	.cfi_startproc
+	pushq	%rbp
+	.cfi_def_cfa_offset 16
+	.cfi_offset 6, -16
+	movq	%rsp, %rbp
+	.cfi_def_cfa_register 6
+	call	func1
+	movl	$0, %eax
+	popq	%rbp
+	.cfi_def_cfa 7, 8
+	ret
+	.cfi_endproc
+.LFE5:
+	.size	main, .-main
+	.ident	"GCC: (nb4 20200810) 7.5.0"
--- a/apitue/sample-code/05/gdb-examples/buf.c
+++ b/apitue/sample-code/05/gdb-examples/buf.c
@ -0,0 +1,45 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* This file is used together with the file 'main.c' to
+ * help students use gdb(1) to understand
+ * manipulations of strings and buffers.
+ *
+ * See https://youtu.be/hgcj7iAxhhU as well as
+ * 'pointer.c'
+ */
+
+
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#define DATA2 "Hello, I'm buf2!"
+#define DATA3 "Hello, I'm buf3!"
+
+void
+printBufs(long n) {
+	char *buf = malloc(n);
+	char *buf2 = malloc(8);
+	char *buf3 = malloc(8);
+
+	strcpy(buf2, DATA2);
+	strcpy(buf3, DATA3);
+	gets(buf);
+
+	printf("buf is : '%s'\n", buf);
+	printf("buf2 is: '%s'\n", buf2);
+	printf("buf3 is: '%s'\n", buf3);
+}
--- a/apitue/sample-code/05/gdb-examples/fib.c
+++ b/apitue/sample-code/05/gdb-examples/fib.c
@ -0,0 +1,49 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* This file is used to illustrate how to step through
+ * a program at execution time using gdb(1).
+ *
+ * To this end, it contains a number of mistakes.
+ *
+ * See https://youtu.be/fOp4Q4mnTD4 for how to fix
+ * them.
+ */
+
+/* The Fibonacci sequence is defined such that each number
+ * is the sum of the two preceding ones. */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+int
+fib(int i) {
+	if (i == 0) {
+		return 0;
+	} else {
+		return fib(i-2) + fib(i-1);
+	}
+}
+
+int
+main(int argc, char **argv) {
+	if (argc != 2) {
+		printf("usage: %s num\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	printf("%d\n", fib(atoi(argv[1])));
+	exit(EXIT_SUCCESS);
+}
--- a/apitue/sample-code/05/gdb-examples/main.c
+++ b/apitue/sample-code/05/gdb-examples/main.c
@ -0,0 +1,36 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* This file is used together with the file 'buf.c' to
+ * help students use gdb(1) to understand
+ * manipulations of strings and buffers.
+ *
+ * See https://youtu.be/hgcj7iAxhhU as well as
+ * 'pointer.c'
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+
+void printBufs(long);
+
+int
+main(int argc, char **argv) {
+	if (argc != 2) {
+		fprintf(stderr, "Usage: %s num\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+	printBufs(strtol(argv[1], NULL, 10));
+}
--- a/apitue/sample-code/05/gdb-examples/pointers.c
+++ b/apitue/sample-code/05/gdb-examples/pointers.c
@ -0,0 +1,56 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* This program is all sorts of terrible.  If I catch
+ * you doing anything like this in your code, you'll
+ * have a hard time getting any points.
+ *
+ * We use this code to illustrate how "strings" work,
+ * as well as how to inspect arrays and pointers using
+ * gdb(1).
+ *
+ * Compile this with '-g'.  Run it as './a.out foo',
+ * then run it in the debugger, break in 'main', and
+ * inspect the different pointers at each step to
+ * better understand what is going on.
+ */
+#include <stdio.h>
+#include <string.h>
+
+int
+main(int argc, char **argv) {
+	char *p = argv[0];
+	char *q = argv[1];
+
+	(void)argc;
+
+	strcat(argv[0], "/");
+	strcat(p, argv[1]);
+
+	printf("argv[0]: %s\n", argv[0]);
+	printf("argv[1]: %s\n\n", argv[1]);
+
+	*(p + 1) = '\0';
+	q[0] = 'm';
+
+	printf("argv[0]: %s\n", argv[0]);
+	printf("argv[0]: %s\n", argv[0]);
+
+	p[1] = '/';
+
+	printf("argv[0]: %s\n", argv[0]);
+
+	return 0;
+}
--- a/apitue/sample-code/05/gdb-examples/simple-ls.c
+++ b/apitue/sample-code/05/gdb-examples/simple-ls.c
@ -0,0 +1,73 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * simple-ls.c
+ * Extremely low-power ls clone.
+ * ./simple-ls .
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <dirent.h>
+#include <errno.h>
+#include <pwd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+void
+printOwner(char *name, struct stat sb) {
+	struct passwd *pwd;
+	pwd = getpwuid(sb.st_uid);
+	printf("%s (%s)\n", name, pwd->pw_name);
+}
+
+int
+main(int argc, char **argv) {
+
+	DIR *dp;
+	struct dirent *dirp;
+
+	if (argc != 2) {
+		fprintf(stderr, "usage: %s dir_name\n", argv[0]);
+		exit(1);
+	}
+
+	if ((dp = opendir(argv[1])) == NULL) {
+		fprintf(stderr, "can't open '%s'\n", argv[1]);
+		exit(1);
+	}
+
+	if (chdir(argv[1]) == -1) {
+		fprintf(stderr, "can't chdir to '%s': %s\n", argv[1], strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	while ((dirp = readdir(dp)) != NULL) {
+		struct stat sb;
+		if (stat(dirp->d_name, &sb) == -1) {
+			fprintf(stderr, "Can't stat %s: %s\n", dirp->d_name,
+						strerror(errno));
+			continue;
+		}
+		printOwner(dirp->d_name, sb);
+	}
+
+	closedir(dp);
+	return(0);
+}
--- a/apitue/sample-code/05/gdb-examples/welcome.c
+++ b/apitue/sample-code/05/gdb-examples/welcome.c
@ -0,0 +1,21 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+#include <stdio.h>
+
+int
+main() {
+	printf("Welcome to CS631 Advanced Programming in the UNIX Environment, %s!\n", getlogin());
+}
--- a/apitue/sample-code/05/make-examples/.print.c.swp
+++ b/apitue/sample-code/05/make-examples/.print.c.swp
--- a/apitue/sample-code/05/make-examples/Makefile
+++ b/apitue/sample-code/05/make-examples/Makefile
@ -0,0 +1,28 @@
+# A slightly better Makefile.  As the first one, but much shorter, since
+# we're using the various built-in rules and definitions in make(1).
+#
+# also see "cpp -M" and "cpp -MM"
+
+PROG=	ls
+OBJS=	cmp.o ls.o main.o print.o stat_flags.o util.o
+
+# If commented out, defaults will be used. If uncommented, these values
+# will be used, even though there is no other explicit mention of this
+# variable in this Makefile.
+#CFLAGS=	-Wall -g
+
+all: ${PROG}
+
+showvars:
+	@echo "CC=${CC}"
+	@echo "CFLAGS=${CFLAGS}"
+	@echo "LDFLAGS=${LDFLAGS}"
+	@echo "PROG=${PROG}"
+	@echo "OBJS=${OBJS}"
+
+${PROG}: ${OBJS}
+	@echo $@ depends on $?
+	${CC} ${LDFLAGS} ${OBJS} -o ${PROG}
+
+clean:
+	rm -f ls *.o
--- a/apitue/sample-code/05/make-examples/Makefile.1
+++ b/apitue/sample-code/05/make-examples/Makefile.1
@ -0,0 +1,36 @@
+# A simplistic Makefile used to illustrate the very basics of make(1).
+# The following Makefiles build on this and show more realistic usage.
+#
+# Run 'make', then 'touch ls.h' and 'make' again.
+
+CC=cc
+
+all: ls
+
+showvars:
+	@echo "CC=${CC}"
+	@echo "CFLAGS=${CFLAGS}"
+
+ls:  cmp.o ls.o main.o print.o stat_flags.o util.o
+	${CC} cmp.o ls.o main.o print.o stat_flags.o util.o -o ls
+
+cmp.o: extern.h ls.h
+	${CC} -c cmp.c
+
+ls.o: extern.h ls.h
+	${CC} -c ls.c
+
+main.o: extern.h ls.h
+	${CC} -c main.c
+
+print.o: extern.h ls.h
+	${CC} -c print.c
+
+stat_flags.o: stat_flags.h
+	${CC} -c stat_flags.c
+
+util.o: extern.h ls.h
+	${CC} -c util.c
+
+clean:
+	rm -f ls *.o
--- a/apitue/sample-code/05/make-examples/Makefile.2
+++ b/apitue/sample-code/05/make-examples/Makefile.2
@ -0,0 +1,19 @@
+# A slightly better Makefile.  As the first one, but much shorter, since
+# we're using the various built-in rules and definitions in make(1).
+
+PROG=	ls
+OBJS=	cmp.o ls.o main.o print.o stat_flags.o util.o
+
+# If commented out, defaults will be used. If uncommented, these values
+# will be used, even though there is no other explicit mention of this
+# variable in this Makefile.
+#CFLAGS=	-Wall -g
+
+all: ${PROG}
+
+${PROG}: ${OBJS}
+	@echo $@ depends on $?
+	${CC} ${LDFLAGS} ${OBJS} -o ${PROG}
+
+clean:
+	rm -f ls *.o
--- a/apitue/sample-code/05/make-examples/Makefile.3
+++ b/apitue/sample-code/05/make-examples/Makefile.3
@ -0,0 +1,29 @@
+# Like the previous Makefiles, only introducing suffixes.  Repeats the
+# lesson that Unix doesn't care what things are named.
+PROG=	ls
+OBJS=	cmp.o ls.b main.b print.b stat_flags.bar util.bar
+CFLAGS=	-Wall -g
+
+.SUFFIXES:  .c .b .bar
+
+all: ${PROG}
+
+showvars:
+	@echo "CC=${CC}"
+	@echo "CFLAGS=${CFLAGS}"
+	@echo "LDFLAGS=${LDFLAGS}"
+	@echo "PROG=${PROG}"
+	@echo "OBJS=${OBJS}"
+
+${PROG}: ${OBJS}
+	@echo $@ depends on $?
+	${CC} ${LDFLAGS} ${OBJS} -o ${PROG}
+
+.c.b:
+	${CC} -c $< -o $@
+
+.c.bar:
+	${CC} ${CFLAGS} -c $< -o $@
+
+clean:
+	rm -f ${PROG} ${OBJS}
--- a/apitue/sample-code/05/make-examples/Makefile.4
+++ b/apitue/sample-code/05/make-examples/Makefile.4
@ -0,0 +1,26 @@
+# Almost identical to 'Makefile.2' - use diff to find out what's
+# different.  Then use both Makefile.2 and Makefile.4 to illustrate
+# precedence of variables.
+PROG=	ls
+OBJS=	cmp.o ls.o main.o print.o stat_flags.o util.o
+
+# If commented out, defaults will be used. If uncommented, these values
+# will be used, even though there is no other explicit mention of this
+# variable in this Makefile.
+CFLAGS=	-Wall -g
+
+all: ${PROG}
+
+showvars:
+	@echo "CC=${CC}"
+	@echo "CFLAGS=${CFLAGS}"
+	@echo "LDFLAGS=${LDFLAGS}"
+	@echo "PROG=${PROG}"
+	@echo "OBJS=${OBJS}"
+
+${PROG}: ${OBJS}
+	@echo $@ depends on $?
+	${CC} ${LDFLAGS} ${OBJS} -o ${PROG}
+
+clean:
+	rm -f ls *.o
--- a/apitue/sample-code/05/make-examples/Makefile.5
+++ b/apitue/sample-code/05/make-examples/Makefile.5
@ -0,0 +1,19 @@
+# A slightly better Makefile.  Let's define a "suffix rule" to
+# create object files from source files.
+# Let's also introduce the concept of variables.
+
+PROG=	ls
+OBJS=	cmp.o ls.o main.o print.o stat_flags.o util.o
+CFLAGS=	-Wall -g
+
+all: ${PROG}
+
+depend:
+	mkdep -- ${CFLAGS} *.c
+
+${PROG}: ${OBJS}
+	@echo $@ depends on $?
+	${CC} ${OBJS} -o ${PROG} ${LDFLAGS}
+
+clean:
+	rm -f ${PROG} ${OBJS}
--- a/apitue/sample-code/05/make-examples/Makefile.new
+++ b/apitue/sample-code/05/make-examples/Makefile.new
@ -0,0 +1,2 @@
+all:
+	cc ${CFLAGS} *.c
--- a/apitue/sample-code/05/make-examples/a.out
+++ b/apitue/sample-code/05/make-examples/a.out
--- a/apitue/sample-code/05/make-examples/cmp.c
+++ b/apitue/sample-code/05/make-examples/cmp.c
@ -0,0 +1,209 @@
+/*	$NetBSD: cmp.c,v 1.17 2003/08/07 09:05:14 agc Exp $	*/
+
+/*
+ * Copyright (c) 1989, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Michael Fischbein.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)cmp.c	8.1 (Berkeley) 5/31/93";
+#else
+__RCSID("$NetBSD: cmp.c,v 1.17 2003/08/07 09:05:14 agc Exp $");
+#endif
+#endif /* not lint */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <fts.h>
+#include <string.h>
+
+#include "ls.h"
+#include "extern.h"
+
+#if defined(_POSIX_SOURCE) || defined(_POSIX_C_SOURCE) || \
+    defined(_XOPEN_SOURCE) || defined(__NetBSD__)
+#define ATIMENSEC_CMP(x, op, y) ((x)->st_atimensec op (y)->st_atimensec)
+#define CTIMENSEC_CMP(x, op, y) ((x)->st_ctimensec op (y)->st_ctimensec)
+#define MTIMENSEC_CMP(x, op, y) ((x)->st_mtimensec op (y)->st_mtimensec)
+#else
+#define ATIMENSEC_CMP(x, op, y) \
+	((x)->st_atimespec.tv_nsec op (y)->st_atimespec.tv_nsec)
+#define CTIMENSEC_CMP(x, op, y) \
+	((x)->st_ctimespec.tv_nsec op (y)->st_ctimespec.tv_nsec)
+#define MTIMENSEC_CMP(x, op, y) \
+	((x)->st_mtimespec.tv_nsec op (y)->st_mtimespec.tv_nsec)
+#endif
+
+int
+namecmp(const FTSENT *a, const FTSENT *b)
+{
+
+	return (strcmp(a->fts_name, b->fts_name));
+}
+
+int
+revnamecmp(const FTSENT *a, const FTSENT *b)
+{
+
+	return (strcmp(b->fts_name, a->fts_name));
+}
+
+int
+modcmp(const FTSENT *a, const FTSENT *b)
+{
+
+	if (b->fts_statp->st_mtime > a->fts_statp->st_mtime)
+		return (1);
+	else if (b->fts_statp->st_mtime < a->fts_statp->st_mtime)
+		return (-1);
+	else if (MTIMENSEC_CMP(b->fts_statp, >, a->fts_statp))
+		return (1);
+	else if (MTIMENSEC_CMP(b->fts_statp, <, a->fts_statp))
+		return (-1);
+	else
+		return (namecmp(a, b));
+}
+
+int
+revmodcmp(const FTSENT *a, const FTSENT *b)
+{
+
+	if (b->fts_statp->st_mtime > a->fts_statp->st_mtime)
+		return (-1);
+	else if (b->fts_statp->st_mtime < a->fts_statp->st_mtime)
+		return (1);
+	else if (MTIMENSEC_CMP(b->fts_statp, >, a->fts_statp))
+		return (-1);
+	else if (MTIMENSEC_CMP(b->fts_statp, <, a->fts_statp))
+		return (1);
+	else
+		return (revnamecmp(a, b));
+}
+
+int
+acccmp(const FTSENT *a, const FTSENT *b)
+{
+
+	if (b->fts_statp->st_atime > a->fts_statp->st_atime)
+		return (1);
+	else if (b->fts_statp->st_atime < a->fts_statp->st_atime)
+		return (-1);
+	else if (ATIMENSEC_CMP(b->fts_statp, >, a->fts_statp))
+		return (1);
+	else if (ATIMENSEC_CMP(b->fts_statp, <, a->fts_statp))
+		return (-1);
+	else
+		return (namecmp(a, b));
+}
+
+int
+revacccmp(const FTSENT *a, const FTSENT *b)
+{
+
+	if (b->fts_statp->st_atime > a->fts_statp->st_atime)
+		return (-1);
+	else if (b->fts_statp->st_atime < a->fts_statp->st_atime)
+		return (1);
+	else if (ATIMENSEC_CMP(b->fts_statp, >, a->fts_statp))
+		return (-1);
+	else if (ATIMENSEC_CMP(b->fts_statp, <, a->fts_statp))
+		return (1);
+	else
+		return (revnamecmp(a, b));
+}
+
+int
+statcmp(const FTSENT *a, const FTSENT *b)
+{
+
+	if (b->fts_statp->st_ctime > a->fts_statp->st_ctime)
+		return (1);
+	else if (b->fts_statp->st_ctime < a->fts_statp->st_ctime)
+		return (-1);
+	else if (CTIMENSEC_CMP(b->fts_statp, >, a->fts_statp))
+		return (1);
+	else if (CTIMENSEC_CMP(b->fts_statp, <, a->fts_statp))
+		return (-1);
+	else
+		return (namecmp(a, b));
+}
+
+int
+revstatcmp(const FTSENT *a, const FTSENT *b)
+{
+
+	if (b->fts_statp->st_ctime > a->fts_statp->st_ctime)
+		return (-1);
+	else if (b->fts_statp->st_ctime < a->fts_statp->st_ctime)
+		return (1);
+	else if (CTIMENSEC_CMP(b->fts_statp, >, a->fts_statp))
+		return (-1);
+	else if (CTIMENSEC_CMP(b->fts_statp, <, a->fts_statp))
+		return (1);
+	else
+		return (revnamecmp(a, b));
+}
+
+int
+sizecmp(const FTSENT *a, const FTSENT *b)
+{
+
+	if (b->fts_statp->st_size > a->fts_statp->st_size)
+		return (1);
+	if (b->fts_statp->st_size < a->fts_statp->st_size)
+		return (-1);
+	else
+		return (namecmp(a, b));
+}
+
+int
+revsizecmp(const FTSENT *a, const FTSENT *b)
+{
+
+	if (b->fts_statp->st_size > a->fts_statp->st_size)
+		return (-1);
+	if (b->fts_statp->st_size < a->fts_statp->st_size)
+		return (1);
+	else
+		return (revnamecmp(a, b));
+}
+
+#if 0
+int
+sillysort(const FTSENT *a, const FTSENT *b)
+{
+	(void)a; (void)b;
+	int n[3] = { -1, 0, 1 };
+	return n[((long)&n)%3];
+}
+#endif
--- a/apitue/sample-code/05/make-examples/extern.h
+++ b/apitue/sample-code/05/make-examples/extern.h
@ -0,0 +1,53 @@
+/*	$NetBSD: extern.h,v 1.17 2011/08/29 14:44:21 joerg Exp $	*/
+
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)extern.h	8.1 (Berkeley) 5/31/93
+ */
+
+int	 acccmp(const FTSENT *, const FTSENT *);
+int	 revacccmp(const FTSENT *, const FTSENT *);
+int	 modcmp(const FTSENT *, const FTSENT *);
+int	 revmodcmp(const FTSENT *, const FTSENT *);
+int	 namecmp(const FTSENT *, const FTSENT *);
+int	 revnamecmp(const FTSENT *, const FTSENT *);
+int	 statcmp(const FTSENT *, const FTSENT *);
+int	 revstatcmp(const FTSENT *, const FTSENT *);
+int	 sizecmp(const FTSENT *, const FTSENT *);
+int	 revsizecmp(const FTSENT *, const FTSENT *);
+
+int	 ls_main(int, char *[]);
+
+int	 printescaped(const char *);
+void	 printacol(DISPLAY *);
+void	 printcol(DISPLAY *);
+void	 printlong(DISPLAY *);
+void	 printscol(DISPLAY *);
+void	 printstream(DISPLAY *);
+int	 safe_print(const char *);
--- a/apitue/sample-code/05/make-examples/ls.c
+++ b/apitue/sample-code/05/make-examples/ls.c
--- a/apitue/sample-code/05/make-examples/ls.h
+++ b/apitue/sample-code/05/make-examples/ls.h
@ -0,0 +1,81 @@
+/*	$NetBSD: ls.h,v 1.19 2014/02/20 18:56:36 christos Exp $	*/
+
+/*
+ * Copyright (c) 1989, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Michael Fischbein.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)ls.h	8.1 (Berkeley) 5/31/93
+ */
+
+#define NO_PRINT	1
+
+extern long blocksize;		/* block size units */
+
+extern int f_accesstime;	/* use time of last access */
+extern int f_flags;		/* show flags associated with a file */
+extern int f_grouponly;		/* long listing without owner */
+extern int f_humanize;		/* humanize size field */
+extern int f_commas;        /* separate size field with commas */
+extern int f_inode;		/* print inode */
+extern int f_longform;		/* long listing format */
+extern int f_octal;		/* print octal escapes for nongraphic characters */
+extern int f_octal_escape;	/* like f_octal but use C escapes if possible */
+extern int f_sectime;		/* print the real time for all files */
+extern int f_size;		/* list size in short listing */
+extern int f_statustime;	/* use time of last mode change */
+extern int f_type;		/* add type character for non-regular files */
+extern int f_typedir;		/* add type character for directories */
+extern int f_nonprint;		/* show unprintables as ? */
+extern int f_fullpath;		/* print full pathname, not filename */
+extern int f_leafonly;		/* when recursing, print leaf names only */
+
+typedef struct {
+	FTSENT *list;
+	u_int64_t btotal;
+	u_int64_t stotal;
+	int entries;
+	unsigned int maxlen;
+	int s_block;
+	int s_flags;
+	int s_group;
+	int s_inode;
+	int s_nlink;
+	int s_size;
+	int s_user;
+	int s_major;
+	int s_minor;
+} DISPLAY;
+
+typedef struct {
+	char *user;
+	char *group;
+	char *flags;
+	char data[1];
+} NAMES;
--- a/apitue/sample-code/05/make-examples/main.c
+++ b/apitue/sample-code/05/make-examples/main.c
@ -0,0 +1,51 @@
+/*	$NetBSD: main.c,v 1.5 2016/09/05 01:00:07 sevan Exp $	*/
+
+/*-
+ * Copyright (c) 1999 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Luke Mewburn.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+
+#ifndef lint
+__RCSID("$NetBSD: main.c,v 1.5 2016/09/05 01:00:07 sevan Exp $");
+#endif /* not lint */
+
+#include <sys/types.h>
+#include <fts.h>
+
+#include "ls.h"
+#include "extern.h"
+#include "stat_flags.h"
+
+int
+main(int argc, char *argv[])
+{
+
+	return ls_main(argc, argv);
+	/* NOTREACHED */
+}
--- a/apitue/sample-code/05/make-examples/print.c
+++ b/apitue/sample-code/05/make-examples/print.c
@ -0,0 +1,497 @@
+/*	$NetBSD: print.c,v 1.55 2014/05/10 09:39:18 martin Exp $	*/
+
+/*
+ * Copyright (c) 1989, 1993, 1994
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Michael Fischbein.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)print.c	8.5 (Berkeley) 7/28/94";
+#else
+__RCSID("$NetBSD: print.c,v 1.55 2014/05/10 09:39:18 martin Exp $");
+#endif
+#endif /* not lint */
+
+#include <sys/param.h>
+#include <sys/stat.h>
+
+#include <err.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <fts.h>
+#include <grp.h>
+#include <pwd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <tzfile.h>
+#include <unistd.h>
+#include <util.h>
+
+#include "ls.h"
+#include "extern.h"
+
+extern int termwidth;
+
+static int	printaname(FTSENT *, int, int);
+static void	printlink(FTSENT *);
+static void	printtime(time_t);
+static void	printtotal(DISPLAY *dp);
+static int	printtype(u_int);
+
+static time_t	now;
+
+#define	IS_NOPRINT(p)	((p)->fts_number == NO_PRINT)
+
+static int
+safe_printpath(const FTSENT *p) {
+	int chcnt;
+
+	if (f_fullpath) {
+		chcnt = safe_print(p->fts_path);
+		chcnt += safe_print("/");
+	} else
+		chcnt = 0;
+	return chcnt + safe_print(p->fts_name);
+}
+
+static int
+printescapedpath(const FTSENT *p) {
+	int chcnt;
+
+	if (f_fullpath) {
+		chcnt = printescaped(p->fts_path);
+		chcnt += printescaped("/");
+	} else
+		chcnt = 0;
+
+	return chcnt + printescaped(p->fts_name);
+}
+
+static int
+printpath(const FTSENT *p) {
+	if (f_fullpath)
+		return printf("%s/%s", p->fts_path, p->fts_name);
+	else
+		return printf("%s", p->fts_name);
+}
+
+void
+printscol(DISPLAY *dp)
+{
+	FTSENT *p;
+
+	for (p = dp->list; p; p = p->fts_link) {
+		if (IS_NOPRINT(p))
+			continue;
+		(void)printaname(p, dp->s_inode, dp->s_block);
+		(void)putchar('\n');
+	}
+}
+
+void
+printlong(DISPLAY *dp)
+{
+	struct stat *sp;
+	FTSENT *p;
+	NAMES *np;
+	char buf[20], szbuf[5];
+
+	now = time(NULL);
+
+	if (!f_leafonly)
+		printtotal(dp);		/* "total: %u\n" */
+	
+	for (p = dp->list; p; p = p->fts_link) {
+		if (IS_NOPRINT(p))
+			continue;
+		sp = p->fts_statp;
+		if (f_inode)
+			(void)printf("%*"PRIu64" ", dp->s_inode, sp->st_ino);
+		if (f_size) {
+			if (f_humanize) {
+				if ((humanize_number(szbuf, sizeof(szbuf),
+				    sp->st_blocks * S_BLKSIZE,
+				    "", HN_AUTOSCALE,
+				    (HN_DECIMAL | HN_B | HN_NOSPACE))) == -1)
+					err(1, "humanize_number");
+				(void)printf("%*s ", dp->s_block, szbuf);
+			} else {
+				(void)printf(f_commas ? "%'*llu " : "%*llu ",
+				    dp->s_block,
+				    (unsigned long long)howmany(sp->st_blocks,
+				    blocksize));
+			}
+		}
+		(void)strmode(sp->st_mode, buf);
+		np = p->fts_pointer;
+		(void)printf("%s %*lu ", buf, dp->s_nlink,
+		    (unsigned long)sp->st_nlink);
+		if (!f_grouponly)
+			(void)printf("%-*s  ", dp->s_user, np->user);
+		(void)printf("%-*s  ", dp->s_group, np->group);
+		if (f_flags)
+			(void)printf("%-*s ", dp->s_flags, np->flags);
+		if (S_ISCHR(sp->st_mode) || S_ISBLK(sp->st_mode))
+			(void)printf("%*lld, %*lld ",
+			    dp->s_major, (long long)major(sp->st_rdev),
+			    dp->s_minor, (long long)minor(sp->st_rdev));
+		else
+			if (f_humanize) {
+				if ((humanize_number(szbuf, sizeof(szbuf),
+				    sp->st_size, "", HN_AUTOSCALE,
+				    (HN_DECIMAL | HN_B | HN_NOSPACE))) == -1)
+					err(1, "humanize_number");
+				(void)printf("%*s ", dp->s_size, szbuf);
+			} else {
+				(void)printf(f_commas ? "%'*llu " : "%*llu ", 
+				    dp->s_size, (unsigned long long)
+				    sp->st_size);
+			}
+		if (f_accesstime)
+			printtime(sp->st_atime);
+		else if (f_statustime)
+			printtime(sp->st_ctime);
+		else
+			printtime(sp->st_mtime);
+		if (f_octal || f_octal_escape)
+			(void)safe_printpath(p);
+		else if (f_nonprint)
+			(void)printescapedpath(p);
+		else
+			(void)printpath(p);
+
+		if (f_type || (f_typedir && S_ISDIR(sp->st_mode)))
+			(void)printtype(sp->st_mode);
+		if (S_ISLNK(sp->st_mode))
+			printlink(p);
+		(void)putchar('\n');
+	}
+}
+
+void
+printcol(DISPLAY *dp)
+{
+	static FTSENT **array;
+	static int lastentries = -1;
+	FTSENT *p;
+	int base, chcnt, col, colwidth, num;
+	int numcols, numrows, row;
+
+	colwidth = dp->maxlen;
+	if (f_inode)
+		colwidth += dp->s_inode + 1;
+	if (f_size) {
+		if (f_humanize)
+			colwidth += dp->s_size + 1;
+		else
+			colwidth += dp->s_block + 1;
+	}
+	if (f_type || f_typedir)
+		colwidth += 1;
+
+	colwidth += 1;
+
+	if (termwidth < 2 * colwidth) {
+		printscol(dp);
+		return;
+	}
+
+	/*
+	 * Have to do random access in the linked list -- build a table
+	 * of pointers.
+	 */
+	if (dp->entries > lastentries) {
+		FTSENT **newarray;
+
+		newarray = realloc(array, dp->entries * sizeof(FTSENT *));
+		if (newarray == NULL) {
+			warn(NULL);
+			printscol(dp);
+			return;
+		}
+		lastentries = dp->entries;
+		array = newarray;
+	}
+	for (p = dp->list, num = 0; p; p = p->fts_link)
+		if (p->fts_number != NO_PRINT)
+			array[num++] = p;
+
+	numcols = termwidth / colwidth;
+	colwidth = termwidth / numcols;		/* spread out if possible */
+	numrows = num / numcols;
+	if (num % numcols)
+		++numrows;
+
+	printtotal(dp);				/* "total: %u\n" */
+
+	for (row = 0; row < numrows; ++row) {
+		for (base = row, chcnt = col = 0; col < numcols; ++col) {
+			chcnt = printaname(array[base], dp->s_inode,
+			    f_humanize ? dp->s_size : dp->s_block);
+			if ((base += numrows) >= num)
+				break;
+			while (chcnt++ < colwidth)
+				(void)putchar(' ');
+		}
+		(void)putchar('\n');
+	}
+}
+
+void
+printacol(DISPLAY *dp)
+{
+	FTSENT *p;
+	int chcnt, col, colwidth;
+	int numcols;
+
+	colwidth = dp->maxlen;
+	if (f_inode)
+		colwidth += dp->s_inode + 1;
+	if (f_size) {
+		if (f_humanize)
+			colwidth += dp->s_size + 1;
+		else
+			colwidth += dp->s_block + 1;
+	}
+	if (f_type || f_typedir)
+		colwidth += 1;
+
+	colwidth += 1;
+
+	if (termwidth < 2 * colwidth) {
+		printscol(dp);
+		return;
+	}
+
+	numcols = termwidth / colwidth;
+	colwidth = termwidth / numcols;		/* spread out if possible */
+
+	printtotal(dp);				/* "total: %u\n" */
+
+	chcnt = col = 0;
+	for (p = dp->list; p; p = p->fts_link) {
+		if (IS_NOPRINT(p))
+			continue;
+		if (col >= numcols) {
+			chcnt = col = 0;
+			(void)putchar('\n');
+		}
+		chcnt = printaname(p, dp->s_inode,
+		    f_humanize ? dp->s_size : dp->s_block);
+		while (chcnt++ < colwidth)
+			(void)putchar(' ');
+		col++;
+	}
+	(void)putchar('\n');
+}
+
+void
+printstream(DISPLAY *dp)
+{
+	FTSENT *p;
+	int col;
+	int extwidth;
+
+	extwidth = 0;
+	if (f_inode)
+		extwidth += dp->s_inode + 1;
+	if (f_size) {
+		if (f_humanize)
+			extwidth += dp->s_size + 1;
+		else 
+			extwidth += dp->s_block + 1;
+	}
+	if (f_type)
+		extwidth += 1;
+
+	for (col = 0, p = dp->list; p != NULL; p = p->fts_link) {
+		if (IS_NOPRINT(p))
+			continue;
+		if (col > 0) {
+			(void)putchar(','), col++;
+			if (col + 1 + extwidth + (int)p->fts_namelen >= termwidth)
+				(void)putchar('\n'), col = 0;
+			else
+				(void)putchar(' '), col++;
+		}
+		col += printaname(p, dp->s_inode,
+		    f_humanize ? dp->s_size : dp->s_block);
+	}
+	(void)putchar('\n');
+}
+
+/*
+ * print [inode] [size] name
+ * return # of characters printed, no trailing characters.
+ */
+static int
+printaname(FTSENT *p, int inodefield, int sizefield)
+{
+	struct stat *sp;
+	int chcnt;
+	char szbuf[5];
+
+	sp = p->fts_statp;
+	chcnt = 0;
+	if (f_inode)
+		chcnt += printf("%*"PRIu64" ", inodefield, sp->st_ino);
+	if (f_size) {
+		if (f_humanize) {
+			if ((humanize_number(szbuf, sizeof(szbuf), sp->st_size,
+			    "", HN_AUTOSCALE,
+			    (HN_DECIMAL | HN_B | HN_NOSPACE))) == -1)
+				err(1, "humanize_number");
+			chcnt += printf("%*s ", sizefield, szbuf);
+		} else {
+			chcnt += printf(f_commas ? "%'*llu " : "%*llu ",
+			    sizefield, (unsigned long long)
+			    howmany(sp->st_blocks, blocksize));
+		}
+	}
+	if (f_octal || f_octal_escape)
+		chcnt += safe_printpath(p);
+	else if (f_nonprint)
+		chcnt += printescapedpath(p);
+	else
+		chcnt += printpath(p);
+	if (f_type || (f_typedir && S_ISDIR(sp->st_mode)))
+		chcnt += printtype(sp->st_mode);
+	return (chcnt);
+}
+
+static void
+printtime(time_t ftime)
+{
+	int i;
+	const char *longstring;
+
+	if ((longstring = ctime(&ftime)) == NULL) {
+			   /* 012345678901234567890123 */
+		longstring = "????????????????????????";
+	}
+	for (i = 4; i < 11; ++i)
+		(void)putchar(longstring[i]);
+
+#define	SIXMONTHS	((DAYSPERNYEAR / 2) * SECSPERDAY)
+	if (f_sectime)
+		for (i = 11; i < 24; i++)
+			(void)putchar(longstring[i]);
+	else if (ftime + SIXMONTHS > now && ftime - SIXMONTHS < now)
+		for (i = 11; i < 16; ++i)
+			(void)putchar(longstring[i]);
+	else {
+		(void)putchar(' ');
+		for (i = 20; i < 24; ++i)
+			(void)putchar(longstring[i]);
+	}
+	(void)putchar(' ');
+}
+
+/*
+ * Display total used disk space in the form "total: %u\n".
+ * Note: POSIX (IEEE Std 1003.1-2001) says this should be always in 512 blocks,
+ * but we humanise it with -h, or separate it with commas with -M, and use 1024
+ * with -k.
+ */
+static void
+printtotal(DISPLAY *dp)
+{
+	char szbuf[5];
+	
+	if (dp->list->fts_level != FTS_ROOTLEVEL && (f_longform || f_size)) {
+		if (f_humanize) {
+			if ((humanize_number(szbuf, sizeof(szbuf), (int64_t)dp->stotal,
+			    "", HN_AUTOSCALE,
+			    (HN_DECIMAL | HN_B | HN_NOSPACE))) == -1)
+				err(1, "humanize_number");
+			(void)printf("total %s\n", szbuf);
+		} else {
+			(void)printf(f_commas ? "total %'llu\n" :
+			    "total %llu\n", (unsigned long long)
+			    howmany(dp->btotal, blocksize));
+		}
+	}
+}
+
+static int
+printtype(u_int mode)
+{
+	switch (mode & S_IFMT) {
+	case S_IFDIR:
+		(void)putchar('/');
+		return (1);
+	case S_IFIFO:
+		(void)putchar('|');
+		return (1);
+	case S_IFLNK:
+		(void)putchar('@');
+		return (1);
+	case S_IFSOCK:
+		(void)putchar('=');
+		return (1);
+	case S_IFWHT:
+		(void)putchar('%');
+		return (1);
+	}
+	if (mode & (S_IXUSR | S_IXGRP | S_IXOTH)) {
+		(void)putchar('*');
+		return (1);
+	}
+	return (0);
+}
+
+static void
+printlink(FTSENT *p)
+{
+	int lnklen;
+	char name[MAXPATHLEN + 1], path[MAXPATHLEN + 1];
+
+	if (p->fts_level == FTS_ROOTLEVEL)
+		(void)snprintf(name, sizeof(name), "%s", p->fts_name);
+	else
+		(void)snprintf(name, sizeof(name),
+		    "%s/%s", p->fts_parent->fts_accpath, p->fts_name);
+	if ((lnklen = readlink(name, path, sizeof(path) - 1)) == -1) {
+		(void)fprintf(stderr, "\nls: %s: %s\n", name, strerror(errno));
+		return;
+	}
+	path[lnklen] = '\0';
+	(void)printf(" -> ");
+	if (f_octal || f_octal_escape)
+		(void)safe_print(path);
+	else if (f_nonprint)
+		(void)printescaped(path);
+	else
+		(void)printf("%s", path);
+}
--- a/apitue/sample-code/05/make-examples/stat_flags.c
+++ b/apitue/sample-code/05/make-examples/stat_flags.c
@ -0,0 +1,181 @@
+/*	$NetBSD: stat_flags.c,v 1.18 2003/10/27 00:12:41 lukem Exp $	*/
+
+/*-
+ * Copyright (c) 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#if HAVE_NBTOOL_CONFIG_H
+#include "nbtool_config.h"
+#else
+#define HAVE_STRUCT_STAT_ST_FLAGS 1
+#endif
+
+#include <sys/cdefs.h>
+#if !defined(lint)
+#if 0
+static char sccsid[] = "@(#)stat_flags.c	8.2 (Berkeley) 7/28/94";
+#else
+__RCSID("$NetBSD: stat_flags.c,v 1.18 2003/10/27 00:12:41 lukem Exp $");
+#endif
+#endif /* not lint */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fts.h>
+#include <stddef.h>
+#include <string.h>
+
+#include "stat_flags.h"
+
+#define	SAPPEND(s) do {							\
+	if (prefix != NULL)						\
+		(void)strlcat(string, prefix, sizeof(string));		\
+	(void)strlcat(string, s, sizeof(string));			\
+	prefix = ",";							\
+} while (/* CONSTCOND */ 0)
+
+/*
+ * flags_to_string --
+ *	Convert stat flags to a comma-separated string.  If no flags
+ *	are set, return the default string.
+ */
+char *
+flags_to_string(u_long flags, const char *def)
+{
+	static char string[128];
+	const char *prefix;
+
+	string[0] = '\0';
+	prefix = NULL;
+#if HAVE_STRUCT_STAT_ST_FLAGS
+	if (flags & UF_APPEND)
+		SAPPEND("uappnd");
+	if (flags & UF_IMMUTABLE)
+		SAPPEND("uchg");
+	if (flags & UF_NODUMP)
+		SAPPEND("nodump");
+	if (flags & UF_OPAQUE)
+		SAPPEND("opaque");
+	if (flags & SF_APPEND)
+		SAPPEND("sappnd");
+	if (flags & SF_ARCHIVED)
+		SAPPEND("arch");
+	if (flags & SF_IMMUTABLE)
+		SAPPEND("schg");
+#endif
+	if (prefix == NULL)
+		strlcpy(string, def, sizeof(string));
+	return (string);
+}
+
+#define	TEST(a, b, f) {							\
+	if (!strcmp(a, b)) {						\
+		if (clear) {						\
+			if (clrp)					\
+				*clrp |= (f);				\
+			if (setp)					\
+				*setp &= ~(f);				\
+		} else {						\
+			if (setp)					\
+				*setp |= (f);				\
+			if (clrp)					\
+				*clrp &= ~(f);				\
+		}							\
+		break;							\
+	}								\
+}
+
+/*
+ * string_to_flags --
+ *	Take string of arguments and return stat flags.  Return 0 on
+ *	success, 1 on failure.  On failure, stringp is set to point
+ *	to the offending token.
+ */
+int
+string_to_flags(char **stringp, u_long *setp, u_long *clrp)
+{
+	int clear;
+	char *string, *p;
+
+	if (setp)
+		*setp = 0;
+	if (clrp)
+		*clrp = 0;
+
+#if HAVE_STRUCT_STAT_ST_FLAGS
+	string = *stringp;
+	while ((p = strsep(&string, "\t ,")) != NULL) {
+		clear = 0;
+		*stringp = p;
+		if (*p == '\0')
+			continue;
+		if (p[0] == 'n' && p[1] == 'o') {
+			clear = 1;
+			p += 2;
+		}
+		switch (p[0]) {
+		case 'a':
+			TEST(p, "arch", SF_ARCHIVED);
+			TEST(p, "archived", SF_ARCHIVED);
+			return (1);
+		case 'd':
+			clear = !clear;
+			TEST(p, "dump", UF_NODUMP);
+			return (1);
+		case 'n':
+				/*
+				 * Support `nonodump'. Note that
+				 * the state of clear is not changed.
+				 */
+			TEST(p, "nodump", UF_NODUMP);
+			return (1);
+		case 'o':
+			TEST(p, "opaque", UF_OPAQUE);
+			return (1);
+		case 's':
+			TEST(p, "sappnd", SF_APPEND);
+			TEST(p, "sappend", SF_APPEND);
+			TEST(p, "schg", SF_IMMUTABLE);
+			TEST(p, "schange", SF_IMMUTABLE);
+			TEST(p, "simmutable", SF_IMMUTABLE);
+			return (1);
+		case 'u':
+			TEST(p, "uappnd", UF_APPEND);
+			TEST(p, "uappend", UF_APPEND);
+			TEST(p, "uchg", UF_IMMUTABLE);
+			TEST(p, "uchange", UF_IMMUTABLE);
+			TEST(p, "uimmutable", UF_IMMUTABLE);
+			return (1);
+		default:
+			return (1);
+		}
+	}
+#endif
+
+	return (0);
+}
--- a/apitue/sample-code/05/make-examples/stat_flags.h
+++ b/apitue/sample-code/05/make-examples/stat_flags.h
@ -0,0 +1,39 @@
+
+
+/*	$NetBSD: stat_flags.h,v 1.4 2003/08/07 09:05:16 agc Exp $	*/
+
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)extern.h	8.1 (Berkeley) 5/31/93
+ */
+
+char	*flags_to_string(u_long, const char *);
+int	 string_to_flags(char **, u_long *, u_long *);
+
+#define DEFAULT_MODE 0644
--- a/apitue/sample-code/05/make-examples/util.c
+++ b/apitue/sample-code/05/make-examples/util.c
@ -0,0 +1,168 @@
+/*	$NetBSD: util.c,v 1.34 2011/08/29 14:44:21 joerg Exp $	*/
+
+/*
+ * Copyright (c) 1989, 1993, 1994
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Michael Fischbein.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)util.c	8.5 (Berkeley) 4/28/95";
+#else
+__RCSID("$NetBSD: util.c,v 1.34 2011/08/29 14:44:21 joerg Exp $");
+#endif
+#endif /* not lint */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <err.h>
+#include <fts.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <vis.h>
+#include <wchar.h>
+#include <wctype.h>
+
+#include "ls.h"
+#include "extern.h"
+
+int
+safe_print(const char *src)
+{
+	size_t len;
+	char *name;
+	int flags;
+
+	flags = VIS_NL | VIS_OCTAL | VIS_WHITE;
+	if (f_octal_escape)
+		flags |= VIS_CSTYLE;
+
+	len = strlen(src);
+	if (len != 0 && SIZE_T_MAX/len <= 4) {
+		errx(EXIT_FAILURE, "%s: name too long", src);
+		/* NOTREACHED */
+	}
+
+	name = (char *)malloc(4*len+1);
+	if (name != NULL) {
+		len = strvis(name, src, flags);
+		(void)printf("%s", name);
+		free(name);
+		return len;
+	} else
+		errx(EXIT_FAILURE, "out of memory!");
+		/* NOTREACHED */
+}
+
+/*
+ * The reasons why we don't use putwchar(wc) here are:
+ * - If wc == L'\0', we need to restore the initial shift state, but
+ *   the C language standard doesn't say that putwchar(L'\0') does.
+ * - It isn't portable to mix a wide-oriented function (i.e. getwchar)
+ *   with byte-oriented functions (printf et al.) in same FILE.
+ */
+static int
+printwc(wchar_t wc, mbstate_t *pst)
+{
+	size_t size;
+	char buf[MB_LEN_MAX];
+
+	size = wcrtomb(buf, wc, pst);
+	if (size == (size_t)-1) /* This shouldn't happen, but for sure */
+		return 0;
+	if (wc == L'\0') {
+		/* The following condition must be always true, but for sure */
+		if (size > 0 && buf[size - 1] == '\0')
+			--size;
+	}
+	if (size > 0)
+		fwrite(buf, 1, size, stdout);
+	return wc == L'\0' ? 0 : wcwidth(wc);
+}
+
+int
+printescaped(const char *src)
+{
+	int n = 0;
+	mbstate_t src_state, stdout_state;
+	/* The following +1 is to pass '\0' at the end of src to mbrtowc(). */
+	const char *endptr = src + strlen(src) + 1;
+
+	/*
+	 * We have to reset src_state each time in this function, because
+	 * the codeset of src pathname may not match with current locale.
+	 * Note that if we pass NULL instead of src_state to mbrtowc(),
+	 * there is no way to reset the state.
+	 */
+	memset(&src_state, 0, sizeof(src_state));
+	memset(&stdout_state, 0, sizeof(stdout_state));
+	while (src < endptr) {
+		wchar_t wc;
+		size_t rv, span = endptr - src;
+
+#if 0
+		/*
+		 * XXX - we should fix libc instead.
+		 * Theoretically this should work, but our current
+		 * implementation of iso2022 module doesn't actually work
+		 * as expected, if there are redundant escape sequences
+		 * which exceed 32 bytes.
+		 */
+		if (span > MB_CUR_MAX)
+			span = MB_CUR_MAX;
+#endif
+		rv = mbrtowc(&wc, src, span, &src_state);
+		if (rv == 0) { /* assert(wc == L'\0'); */
+			/* The following may output a shift sequence. */
+			n += printwc(wc, &stdout_state);
+			break;
+		}
+		if (rv == (size_t)-1) { /* probably errno == EILSEQ */
+			n += printwc(L'?', &stdout_state);
+			/* try to skip 1byte, because there is no better way */
+			src++;
+			memset(&src_state, 0, sizeof(src_state));
+		} else if (rv == (size_t)-2) {
+			if (span < MB_CUR_MAX) { /* incomplete char */
+				n += printwc(L'?', &stdout_state);
+				break;
+			}
+			src += span; /* a redundant shift sequence? */
+		} else {
+			n += printwc(iswprint(wc) ? wc : L'?', &stdout_state);
+			src += rv;
+		}
+	}
+	return n;
+}
--- a/apitue/sample-code/05/make/Makefile
+++ b/apitue/sample-code/05/make/Makefile
@ -0,0 +1,19 @@
+# A slightly better Makefile.  Let's define a "suffix rule" to
+# create object files from source files.
+# Let's also introduce the concept of variables.
+
+PROG=	ls
+OBJS=	cmp.o ls.o main.o print.o stat_flags.o util.o
+CFLAGS=	-Wall -g
+
+all: ${PROG}
+
+depend:
+	mkdep -- ${CFLAGS} *.c
+
+${PROG}: ${OBJS}
+	@echo $@ depends on $?
+	${CC} ${OBJS} -o ${PROG} ${LDFLAGS}
+
+clean:
+	rm -f ${PROG} ${OBJS}
--- a/apitue/sample-code/05/make/cmp.c
+++ b/apitue/sample-code/05/make/cmp.c
@ -0,0 +1,209 @@
+/*	$NetBSD: cmp.c,v 1.17 2003/08/07 09:05:14 agc Exp $	*/
+
+/*
+ * Copyright (c) 1989, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Michael Fischbein.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)cmp.c	8.1 (Berkeley) 5/31/93";
+#else
+__RCSID("$NetBSD: cmp.c,v 1.17 2003/08/07 09:05:14 agc Exp $");
+#endif
+#endif /* not lint */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <fts.h>
+#include <string.h>
+
+#include "ls.h"
+#include "extern.h"
+
+#if defined(_POSIX_SOURCE) || defined(_POSIX_C_SOURCE) || \
+    defined(_XOPEN_SOURCE) || defined(__NetBSD__)
+#define ATIMENSEC_CMP(x, op, y) ((x)->st_atimensec op (y)->st_atimensec)
+#define CTIMENSEC_CMP(x, op, y) ((x)->st_ctimensec op (y)->st_ctimensec)
+#define MTIMENSEC_CMP(x, op, y) ((x)->st_mtimensec op (y)->st_mtimensec)
+#else
+#define ATIMENSEC_CMP(x, op, y) \
+	((x)->st_atimespec.tv_nsec op (y)->st_atimespec.tv_nsec)
+#define CTIMENSEC_CMP(x, op, y) \
+	((x)->st_ctimespec.tv_nsec op (y)->st_ctimespec.tv_nsec)
+#define MTIMENSEC_CMP(x, op, y) \
+	((x)->st_mtimespec.tv_nsec op (y)->st_mtimespec.tv_nsec)
+#endif
+
+int
+namecmp(const FTSENT *a, const FTSENT *b)
+{
+
+	return (strcmp(a->fts_name, b->fts_name));
+}
+
+int
+revnamecmp(const FTSENT *a, const FTSENT *b)
+{
+
+	return (strcmp(b->fts_name, a->fts_name));
+}
+
+int
+modcmp(const FTSENT *a, const FTSENT *b)
+{
+
+	if (b->fts_statp->st_mtime > a->fts_statp->st_mtime)
+		return (1);
+	else if (b->fts_statp->st_mtime < a->fts_statp->st_mtime)
+		return (-1);
+	else if (MTIMENSEC_CMP(b->fts_statp, >, a->fts_statp))
+		return (1);
+	else if (MTIMENSEC_CMP(b->fts_statp, <, a->fts_statp))
+		return (-1);
+	else
+		return (namecmp(a, b));
+}
+
+int
+revmodcmp(const FTSENT *a, const FTSENT *b)
+{
+
+	if (b->fts_statp->st_mtime > a->fts_statp->st_mtime)
+		return (-1);
+	else if (b->fts_statp->st_mtime < a->fts_statp->st_mtime)
+		return (1);
+	else if (MTIMENSEC_CMP(b->fts_statp, >, a->fts_statp))
+		return (-1);
+	else if (MTIMENSEC_CMP(b->fts_statp, <, a->fts_statp))
+		return (1);
+	else
+		return (revnamecmp(a, b));
+}
+
+int
+acccmp(const FTSENT *a, const FTSENT *b)
+{
+
+	if (b->fts_statp->st_atime > a->fts_statp->st_atime)
+		return (1);
+	else if (b->fts_statp->st_atime < a->fts_statp->st_atime)
+		return (-1);
+	else if (ATIMENSEC_CMP(b->fts_statp, >, a->fts_statp))
+		return (1);
+	else if (ATIMENSEC_CMP(b->fts_statp, <, a->fts_statp))
+		return (-1);
+	else
+		return (namecmp(a, b));
+}
+
+int
+revacccmp(const FTSENT *a, const FTSENT *b)
+{
+
+	if (b->fts_statp->st_atime > a->fts_statp->st_atime)
+		return (-1);
+	else if (b->fts_statp->st_atime < a->fts_statp->st_atime)
+		return (1);
+	else if (ATIMENSEC_CMP(b->fts_statp, >, a->fts_statp))
+		return (-1);
+	else if (ATIMENSEC_CMP(b->fts_statp, <, a->fts_statp))
+		return (1);
+	else
+		return (revnamecmp(a, b));
+}
+
+int
+statcmp(const FTSENT *a, const FTSENT *b)
+{
+
+	if (b->fts_statp->st_ctime > a->fts_statp->st_ctime)
+		return (1);
+	else if (b->fts_statp->st_ctime < a->fts_statp->st_ctime)
+		return (-1);
+	else if (CTIMENSEC_CMP(b->fts_statp, >, a->fts_statp))
+		return (1);
+	else if (CTIMENSEC_CMP(b->fts_statp, <, a->fts_statp))
+		return (-1);
+	else
+		return (namecmp(a, b));
+}
+
+int
+revstatcmp(const FTSENT *a, const FTSENT *b)
+{
+
+	if (b->fts_statp->st_ctime > a->fts_statp->st_ctime)
+		return (-1);
+	else if (b->fts_statp->st_ctime < a->fts_statp->st_ctime)
+		return (1);
+	else if (CTIMENSEC_CMP(b->fts_statp, >, a->fts_statp))
+		return (-1);
+	else if (CTIMENSEC_CMP(b->fts_statp, <, a->fts_statp))
+		return (1);
+	else
+		return (revnamecmp(a, b));
+}
+
+int
+sizecmp(const FTSENT *a, const FTSENT *b)
+{
+
+	if (b->fts_statp->st_size > a->fts_statp->st_size)
+		return (1);
+	if (b->fts_statp->st_size < a->fts_statp->st_size)
+		return (-1);
+	else
+		return (namecmp(a, b));
+}
+
+int
+revsizecmp(const FTSENT *a, const FTSENT *b)
+{
+
+	if (b->fts_statp->st_size > a->fts_statp->st_size)
+		return (-1);
+	if (b->fts_statp->st_size < a->fts_statp->st_size)
+		return (1);
+	else
+		return (revnamecmp(a, b));
+}
+
+#if 0
+int
+sillysort(const FTSENT *a, const FTSENT *b)
+{
+	(void)a; (void)b;
+	int n[3] = { -1, 0, 1 };
+	return n[((long)&n)%3];
+}
+#endif
--- a/apitue/sample-code/05/make/extern.h
+++ b/apitue/sample-code/05/make/extern.h
@ -0,0 +1,53 @@
+/*	$NetBSD: extern.h,v 1.17 2011/08/29 14:44:21 joerg Exp $	*/
+
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)extern.h	8.1 (Berkeley) 5/31/93
+ */
+
+int	 acccmp(const FTSENT *, const FTSENT *);
+int	 revacccmp(const FTSENT *, const FTSENT *);
+int	 modcmp(const FTSENT *, const FTSENT *);
+int	 revmodcmp(const FTSENT *, const FTSENT *);
+int	 namecmp(const FTSENT *, const FTSENT *);
+int	 revnamecmp(const FTSENT *, const FTSENT *);
+int	 statcmp(const FTSENT *, const FTSENT *);
+int	 revstatcmp(const FTSENT *, const FTSENT *);
+int	 sizecmp(const FTSENT *, const FTSENT *);
+int	 revsizecmp(const FTSENT *, const FTSENT *);
+
+int	 ls_main(int, char *[]);
+
+int	 printescaped(const char *);
+void	 printacol(DISPLAY *);
+void	 printcol(DISPLAY *);
+void	 printlong(DISPLAY *);
+void	 printscol(DISPLAY *);
+void	 printstream(DISPLAY *);
+int	 safe_print(const char *);
--- a/apitue/sample-code/05/make/ls.c
+++ b/apitue/sample-code/05/make/ls.c
--- a/apitue/sample-code/05/make/ls.h
+++ b/apitue/sample-code/05/make/ls.h
@ -0,0 +1,81 @@
+/*	$NetBSD: ls.h,v 1.19 2014/02/20 18:56:36 christos Exp $	*/
+
+/*
+ * Copyright (c) 1989, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Michael Fischbein.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)ls.h	8.1 (Berkeley) 5/31/93
+ */
+
+#define NO_PRINT	1
+
+extern long blocksize;		/* block size units */
+
+extern int f_accesstime;	/* use time of last access */
+extern int f_flags;		/* show flags associated with a file */
+extern int f_grouponly;		/* long listing without owner */
+extern int f_humanize;		/* humanize size field */
+extern int f_commas;        /* separate size field with commas */
+extern int f_inode;		/* print inode */
+extern int f_longform;		/* long listing format */
+extern int f_octal;		/* print octal escapes for nongraphic characters */
+extern int f_octal_escape;	/* like f_octal but use C escapes if possible */
+extern int f_sectime;		/* print the real time for all files */
+extern int f_size;		/* list size in short listing */
+extern int f_statustime;	/* use time of last mode change */
+extern int f_type;		/* add type character for non-regular files */
+extern int f_typedir;		/* add type character for directories */
+extern int f_nonprint;		/* show unprintables as ? */
+extern int f_fullpath;		/* print full pathname, not filename */
+extern int f_leafonly;		/* when recursing, print leaf names only */
+
+typedef struct {
+	FTSENT *list;
+	u_int64_t btotal;
+	u_int64_t stotal;
+	int entries;
+	unsigned int maxlen;
+	int s_block;
+	int s_flags;
+	int s_group;
+	int s_inode;
+	int s_nlink;
+	int s_size;
+	int s_user;
+	int s_major;
+	int s_minor;
+} DISPLAY;
+
+typedef struct {
+	char *user;
+	char *group;
+	char *flags;
+	char data[1];
+} NAMES;
--- a/apitue/sample-code/05/make/main.c
+++ b/apitue/sample-code/05/make/main.c
@ -0,0 +1,51 @@
+/*	$NetBSD: main.c,v 1.5 2016/09/05 01:00:07 sevan Exp $	*/
+
+/*-
+ * Copyright (c) 1999 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Luke Mewburn.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+
+#ifndef lint
+__RCSID("$NetBSD: main.c,v 1.5 2016/09/05 01:00:07 sevan Exp $");
+#endif /* not lint */
+
+#include <sys/types.h>
+#include <fts.h>
+
+#include "ls.h"
+#include "extern.h"
+#include "stat_flags.h"
+
+int
+main(int argc, char *argv[])
+{
+
+	return ls_main(argc, argv);
+	/* NOTREACHED */
+}
--- a/apitue/sample-code/05/make/print.c
+++ b/apitue/sample-code/05/make/print.c
@ -0,0 +1,497 @@
+/*	$NetBSD: print.c,v 1.55 2014/05/10 09:39:18 martin Exp $	*/
+
+/*
+ * Copyright (c) 1989, 1993, 1994
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Michael Fischbein.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)print.c	8.5 (Berkeley) 7/28/94";
+#else
+__RCSID("$NetBSD: print.c,v 1.55 2014/05/10 09:39:18 martin Exp $");
+#endif
+#endif /* not lint */
+
+#include <sys/param.h>
+#include <sys/stat.h>
+
+#include <err.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <fts.h>
+#include <grp.h>
+#include <pwd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <tzfile.h>
+#include <unistd.h>
+#include <util.h>
+
+#include "ls.h"
+#include "extern.h"
+
+extern int termwidth;
+
+static int	printaname(FTSENT *, int, int);
+static void	printlink(FTSENT *);
+static void	printtime(time_t);
+static void	printtotal(DISPLAY *dp);
+static int	printtype(u_int);
+
+static time_t	now;
+
+#define	IS_NOPRINT(p)	((p)->fts_number == NO_PRINT)
+
+static int
+safe_printpath(const FTSENT *p) {
+	int chcnt;
+
+	if (f_fullpath) {
+		chcnt = safe_print(p->fts_path);
+		chcnt += safe_print("/");
+	} else
+		chcnt = 0;
+	return chcnt + safe_print(p->fts_name);
+}
+
+static int
+printescapedpath(const FTSENT *p) {
+	int chcnt;
+
+	if (f_fullpath) {
+		chcnt = printescaped(p->fts_path);
+		chcnt += printescaped("/");
+	} else
+		chcnt = 0;
+
+	return chcnt + printescaped(p->fts_name);
+}
+
+static int
+printpath(const FTSENT *p) {
+	if (f_fullpath)
+		return printf("%s/%s", p->fts_path, p->fts_name);
+	else
+		return printf("%s", p->fts_name);
+}
+
+void
+printscol(DISPLAY *dp)
+{
+	FTSENT *p;
+
+	for (p = dp->list; p; p = p->fts_link) {
+		if (IS_NOPRINT(p))
+			continue;
+		(void)printaname(p, dp->s_inode, dp->s_block);
+		(void)putchar('\n');
+	}
+}
+
+void
+printlong(DISPLAY *dp)
+{
+	struct stat *sp;
+	FTSENT *p;
+	NAMES *np;
+	char buf[20], szbuf[5];
+
+	now = time(NULL);
+
+	if (!f_leafonly)
+		printtotal(dp);		/* "total: %u\n" */
+	
+	for (p = dp->list; p; p = p->fts_link) {
+		if (IS_NOPRINT(p))
+			continue;
+		sp = p->fts_statp;
+		if (f_inode)
+			(void)printf("%*"PRIu64" ", dp->s_inode, sp->st_ino);
+		if (f_size) {
+			if (f_humanize) {
+				if ((humanize_number(szbuf, sizeof(szbuf),
+				    sp->st_blocks * S_BLKSIZE,
+				    "", HN_AUTOSCALE,
+				    (HN_DECIMAL | HN_B | HN_NOSPACE))) == -1)
+					err(1, "humanize_number");
+				(void)printf("%*s ", dp->s_block, szbuf);
+			} else {
+				(void)printf(f_commas ? "%'*llu " : "%*llu ",
+				    dp->s_block,
+				    (unsigned long long)howmany(sp->st_blocks,
+				    blocksize));
+			}
+		}
+		(void)strmode(sp->st_mode, buf);
+		np = p->fts_pointer;
+		(void)printf("%s %*lu ", buf, dp->s_nlink,
+		    (unsigned long)sp->st_nlink);
+		if (!f_grouponly)
+			(void)printf("%-*s  ", dp->s_user, np->user);
+		(void)printf("%-*s  ", dp->s_group, np->group);
+		if (f_flags)
+			(void)printf("%-*s ", dp->s_flags, np->flags);
+		if (S_ISCHR(sp->st_mode) || S_ISBLK(sp->st_mode))
+			(void)printf("%*lld, %*lld ",
+			    dp->s_major, (long long)major(sp->st_rdev),
+			    dp->s_minor, (long long)minor(sp->st_rdev));
+		else
+			if (f_humanize) {
+				if ((humanize_number(szbuf, sizeof(szbuf),
+				    sp->st_size, "", HN_AUTOSCALE,
+				    (HN_DECIMAL | HN_B | HN_NOSPACE))) == -1)
+					err(1, "humanize_number");
+				(void)printf("%*s ", dp->s_size, szbuf);
+			} else {
+				(void)printf(f_commas ? "%'*llu " : "%*llu ", 
+				    dp->s_size, (unsigned long long)
+				    sp->st_size);
+			}
+		if (f_accesstime)
+			printtime(sp->st_atime);
+		else if (f_statustime)
+			printtime(sp->st_ctime);
+		else
+			printtime(sp->st_mtime);
+		if (f_octal || f_octal_escape)
+			(void)safe_printpath(p);
+		else if (f_nonprint)
+			(void)printescapedpath(p);
+		else
+			(void)printpath(p);
+
+		if (f_type || (f_typedir && S_ISDIR(sp->st_mode)))
+			(void)printtype(sp->st_mode);
+		if (S_ISLNK(sp->st_mode))
+			printlink(p);
+		(void)putchar('\n');
+	}
+}
+
+void
+printcol(DISPLAY *dp)
+{
+	static FTSENT **array;
+	static int lastentries = -1;
+	FTSENT *p;
+	int base, chcnt, col, colwidth, num;
+	int numcols, numrows, row;
+
+	colwidth = dp->maxlen;
+	if (f_inode)
+		colwidth += dp->s_inode + 1;
+	if (f_size) {
+		if (f_humanize)
+			colwidth += dp->s_size + 1;
+		else
+			colwidth += dp->s_block + 1;
+	}
+	if (f_type || f_typedir)
+		colwidth += 1;
+
+	colwidth += 1;
+
+	if (termwidth < 2 * colwidth) {
+		printscol(dp);
+		return;
+	}
+
+	/*
+	 * Have to do random access in the linked list -- build a table
+	 * of pointers.
+	 */
+	if (dp->entries > lastentries) {
+		FTSENT **newarray;
+
+		newarray = realloc(array, dp->entries * sizeof(FTSENT *));
+		if (newarray == NULL) {
+			warn(NULL);
+			printscol(dp);
+			return;
+		}
+		lastentries = dp->entries;
+		array = newarray;
+	}
+	for (p = dp->list, num = 0; p; p = p->fts_link)
+		if (p->fts_number != NO_PRINT)
+			array[num++] = p;
+
+	numcols = termwidth / colwidth;
+	colwidth = termwidth / numcols;		/* spread out if possible */
+	numrows = num / numcols;
+	if (num % numcols)
+		++numrows;
+
+	printtotal(dp);				/* "total: %u\n" */
+
+	for (row = 0; row < numrows; ++row) {
+		for (base = row, chcnt = col = 0; col < numcols; ++col) {
+			chcnt = printaname(array[base], dp->s_inode,
+			    f_humanize ? dp->s_size : dp->s_block);
+			if ((base += numrows) >= num)
+				break;
+			while (chcnt++ < colwidth)
+				(void)putchar(' ');
+		}
+		(void)putchar('\n');
+	}
+}
+
+void
+printacol(DISPLAY *dp)
+{
+	FTSENT *p;
+	int chcnt, col, colwidth;
+	int numcols;
+
+	colwidth = dp->maxlen;
+	if (f_inode)
+		colwidth += dp->s_inode + 1;
+	if (f_size) {
+		if (f_humanize)
+			colwidth += dp->s_size + 1;
+		else
+			colwidth += dp->s_block + 1;
+	}
+	if (f_type || f_typedir)
+		colwidth += 1;
+
+	colwidth += 1;
+
+	if (termwidth < 2 * colwidth) {
+		printscol(dp);
+		return;
+	}
+
+	numcols = termwidth / colwidth;
+	colwidth = termwidth / numcols;		/* spread out if possible */
+
+	printtotal(dp);				/* "total: %u\n" */
+
+	chcnt = col = 0;
+	for (p = dp->list; p; p = p->fts_link) {
+		if (IS_NOPRINT(p))
+			continue;
+		if (col >= numcols) {
+			chcnt = col = 0;
+			(void)putchar('\n');
+		}
+		chcnt = printaname(p, dp->s_inode,
+		    f_humanize ? dp->s_size : dp->s_block);
+		while (chcnt++ < colwidth)
+			(void)putchar(' ');
+		col++;
+	}
+	(void)putchar('\n');
+}
+
+void
+printstream(DISPLAY *dp)
+{
+	FTSENT *p;
+	int col;
+	int extwidth;
+
+	extwidth = 0;
+	if (f_inode)
+		extwidth += dp->s_inode + 1;
+	if (f_size) {
+		if (f_humanize)
+			extwidth += dp->s_size + 1;
+		else 
+			extwidth += dp->s_block + 1;
+	}
+	if (f_type)
+		extwidth += 1;
+
+	for (col = 0, p = dp->list; p != NULL; p = p->fts_link) {
+		if (IS_NOPRINT(p))
+			continue;
+		if (col > 0) {
+			(void)putchar(','), col++;
+			if (col + 1 + extwidth + (int)p->fts_namelen >= termwidth)
+				(void)putchar('\n'), col = 0;
+			else
+				(void)putchar(' '), col++;
+		}
+		col += printaname(p, dp->s_inode,
+		    f_humanize ? dp->s_size : dp->s_block);
+	}
+	(void)putchar('\n');
+}
+
+/*
+ * print [inode] [size] name
+ * return # of characters printed, no trailing characters.
+ */
+static int
+printaname(FTSENT *p, int inodefield, int sizefield)
+{
+	struct stat *sp;
+	int chcnt;
+	char szbuf[5];
+
+	sp = p->fts_statp;
+	chcnt = 0;
+	if (f_inode)
+		chcnt += printf("%*"PRIu64" ", inodefield, sp->st_ino);
+	if (f_size) {
+		if (f_humanize) {
+			if ((humanize_number(szbuf, sizeof(szbuf), sp->st_size,
+			    "", HN_AUTOSCALE,
+			    (HN_DECIMAL | HN_B | HN_NOSPACE))) == -1)
+				err(1, "humanize_number");
+			chcnt += printf("%*s ", sizefield, szbuf);
+		} else {
+			chcnt += printf(f_commas ? "%'*llu " : "%*llu ",
+			    sizefield, (unsigned long long)
+			    howmany(sp->st_blocks, blocksize));
+		}
+	}
+	if (f_octal || f_octal_escape)
+		chcnt += safe_printpath(p);
+	else if (f_nonprint)
+		chcnt += printescapedpath(p);
+	else
+		chcnt += printpath(p);
+	if (f_type || (f_typedir && S_ISDIR(sp->st_mode)))
+		chcnt += printtype(sp->st_mode);
+	return (chcnt);
+}
+
+static void
+printtime(time_t ftime)
+{
+	int i;
+	const char *longstring;
+
+	if ((longstring = ctime(&ftime)) == NULL) {
+			   /* 012345678901234567890123 */
+		longstring = "????????????????????????";
+	}
+	for (i = 4; i < 11; ++i)
+		(void)putchar(longstring[i]);
+
+#define	SIXMONTHS	((DAYSPERNYEAR / 2) * SECSPERDAY)
+	if (f_sectime)
+		for (i = 11; i < 24; i++)
+			(void)putchar(longstring[i]);
+	else if (ftime + SIXMONTHS > now && ftime - SIXMONTHS < now)
+		for (i = 11; i < 16; ++i)
+			(void)putchar(longstring[i]);
+	else {
+		(void)putchar(' ');
+		for (i = 20; i < 24; ++i)
+			(void)putchar(longstring[i]);
+	}
+	(void)putchar(' ');
+}
+
+/*
+ * Display total used disk space in the form "total: %u\n".
+ * Note: POSIX (IEEE Std 1003.1-2001) says this should be always in 512 blocks,
+ * but we humanise it with -h, or separate it with commas with -M, and use 1024
+ * with -k.
+ */
+static void
+printtotal(DISPLAY *dp)
+{
+	char szbuf[5];
+	
+	if (dp->list->fts_level != FTS_ROOTLEVEL && (f_longform || f_size)) {
+		if (f_humanize) {
+			if ((humanize_number(szbuf, sizeof(szbuf), (int64_t)dp->stotal,
+			    "", HN_AUTOSCALE,
+			    (HN_DECIMAL | HN_B | HN_NOSPACE))) == -1)
+				err(1, "humanize_number");
+			(void)printf("total %s\n", szbuf);
+		} else {
+			(void)printf(f_commas ? "total %'llu\n" :
+			    "total %llu\n", (unsigned long long)
+			    howmany(dp->btotal, blocksize));
+		}
+	}
+}
+
+static int
+printtype(u_int mode)
+{
+	switch (mode & S_IFMT) {
+	case S_IFDIR:
+		(void)putchar('/');
+		return (1);
+	case S_IFIFO:
+		(void)putchar('|');
+		return (1);
+	case S_IFLNK:
+		(void)putchar('@');
+		return (1);
+	case S_IFSOCK:
+		(void)putchar('=');
+		return (1);
+	case S_IFWHT:
+		(void)putchar('%');
+		return (1);
+	}
+	if (mode & (S_IXUSR | S_IXGRP | S_IXOTH)) {
+		(void)putchar('*');
+		return (1);
+	}
+	return (0);
+}
+
+static void
+printlink(FTSENT *p)
+{
+	int lnklen;
+	char name[MAXPATHLEN + 1], path[MAXPATHLEN + 1];
+
+	if (p->fts_level == FTS_ROOTLEVEL)
+		(void)snprintf(name, sizeof(name), "%s", p->fts_name);
+	else
+		(void)snprintf(name, sizeof(name),
+		    "%s/%s", p->fts_parent->fts_accpath, p->fts_name);
+	if ((lnklen = readlink(name, path, sizeof(path) - 1)) == -1) {
+		(void)fprintf(stderr, "\nls: %s: %s\n", name, strerror(errno));
+		return;
+	}
+	path[lnklen] = '\0';
+	(void)printf(" -> ");
+	if (f_octal || f_octal_escape)
+		(void)safe_print(path);
+	else if (f_nonprint)
+		(void)printescaped(path);
+	else
+		(void)printf("%s", path);
+}
--- a/apitue/sample-code/05/make/stat_flags.c
+++ b/apitue/sample-code/05/make/stat_flags.c
@ -0,0 +1,181 @@
+/*	$NetBSD: stat_flags.c,v 1.18 2003/10/27 00:12:41 lukem Exp $	*/
+
+/*-
+ * Copyright (c) 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#if HAVE_NBTOOL_CONFIG_H
+#include "nbtool_config.h"
+#else
+#define HAVE_STRUCT_STAT_ST_FLAGS 1
+#endif
+
+#include <sys/cdefs.h>
+#if !defined(lint)
+#if 0
+static char sccsid[] = "@(#)stat_flags.c	8.2 (Berkeley) 7/28/94";
+#else
+__RCSID("$NetBSD: stat_flags.c,v 1.18 2003/10/27 00:12:41 lukem Exp $");
+#endif
+#endif /* not lint */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fts.h>
+#include <stddef.h>
+#include <string.h>
+
+#include "stat_flags.h"
+
+#define	SAPPEND(s) do {							\
+	if (prefix != NULL)						\
+		(void)strlcat(string, prefix, sizeof(string));		\
+	(void)strlcat(string, s, sizeof(string));			\
+	prefix = ",";							\
+} while (/* CONSTCOND */ 0)
+
+/*
+ * flags_to_string --
+ *	Convert stat flags to a comma-separated string.  If no flags
+ *	are set, return the default string.
+ */
+char *
+flags_to_string(u_long flags, const char *def)
+{
+	static char string[128];
+	const char *prefix;
+
+	string[0] = '\0';
+	prefix = NULL;
+#if HAVE_STRUCT_STAT_ST_FLAGS
+	if (flags & UF_APPEND)
+		SAPPEND("uappnd");
+	if (flags & UF_IMMUTABLE)
+		SAPPEND("uchg");
+	if (flags & UF_NODUMP)
+		SAPPEND("nodump");
+	if (flags & UF_OPAQUE)
+		SAPPEND("opaque");
+	if (flags & SF_APPEND)
+		SAPPEND("sappnd");
+	if (flags & SF_ARCHIVED)
+		SAPPEND("arch");
+	if (flags & SF_IMMUTABLE)
+		SAPPEND("schg");
+#endif
+	if (prefix == NULL)
+		strlcpy(string, def, sizeof(string));
+	return (string);
+}
+
+#define	TEST(a, b, f) {							\
+	if (!strcmp(a, b)) {						\
+		if (clear) {						\
+			if (clrp)					\
+				*clrp |= (f);				\
+			if (setp)					\
+				*setp &= ~(f);				\
+		} else {						\
+			if (setp)					\
+				*setp |= (f);				\
+			if (clrp)					\
+				*clrp &= ~(f);				\
+		}							\
+		break;							\
+	}								\
+}
+
+/*
+ * string_to_flags --
+ *	Take string of arguments and return stat flags.  Return 0 on
+ *	success, 1 on failure.  On failure, stringp is set to point
+ *	to the offending token.
+ */
+int
+string_to_flags(char **stringp, u_long *setp, u_long *clrp)
+{
+	int clear;
+	char *string, *p;
+
+	if (setp)
+		*setp = 0;
+	if (clrp)
+		*clrp = 0;
+
+#if HAVE_STRUCT_STAT_ST_FLAGS
+	string = *stringp;
+	while ((p = strsep(&string, "\t ,")) != NULL) {
+		clear = 0;
+		*stringp = p;
+		if (*p == '\0')
+			continue;
+		if (p[0] == 'n' && p[1] == 'o') {
+			clear = 1;
+			p += 2;
+		}
+		switch (p[0]) {
+		case 'a':
+			TEST(p, "arch", SF_ARCHIVED);
+			TEST(p, "archived", SF_ARCHIVED);
+			return (1);
+		case 'd':
+			clear = !clear;
+			TEST(p, "dump", UF_NODUMP);
+			return (1);
+		case 'n':
+				/*
+				 * Support `nonodump'. Note that
+				 * the state of clear is not changed.
+				 */
+			TEST(p, "nodump", UF_NODUMP);
+			return (1);
+		case 'o':
+			TEST(p, "opaque", UF_OPAQUE);
+			return (1);
+		case 's':
+			TEST(p, "sappnd", SF_APPEND);
+			TEST(p, "sappend", SF_APPEND);
+			TEST(p, "schg", SF_IMMUTABLE);
+			TEST(p, "schange", SF_IMMUTABLE);
+			TEST(p, "simmutable", SF_IMMUTABLE);
+			return (1);
+		case 'u':
+			TEST(p, "uappnd", UF_APPEND);
+			TEST(p, "uappend", UF_APPEND);
+			TEST(p, "uchg", UF_IMMUTABLE);
+			TEST(p, "uchange", UF_IMMUTABLE);
+			TEST(p, "uimmutable", UF_IMMUTABLE);
+			return (1);
+		default:
+			return (1);
+		}
+	}
+#endif
+
+	return (0);
+}
--- a/apitue/sample-code/05/make/stat_flags.h
+++ b/apitue/sample-code/05/make/stat_flags.h
@ -0,0 +1,39 @@
+
+
+/*	$NetBSD: stat_flags.h,v 1.4 2003/08/07 09:05:16 agc Exp $	*/
+
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)extern.h	8.1 (Berkeley) 5/31/93
+ */
+
+char	*flags_to_string(u_long, const char *);
+int	 string_to_flags(char **, u_long *, u_long *);
+
+#define DEFAULT_MODE 0644
--- a/apitue/sample-code/05/make/util.c
+++ b/apitue/sample-code/05/make/util.c
@ -0,0 +1,168 @@
+/*	$NetBSD: util.c,v 1.34 2011/08/29 14:44:21 joerg Exp $	*/
+
+/*
+ * Copyright (c) 1989, 1993, 1994
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Michael Fischbein.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)util.c	8.5 (Berkeley) 4/28/95";
+#else
+__RCSID("$NetBSD: util.c,v 1.34 2011/08/29 14:44:21 joerg Exp $");
+#endif
+#endif /* not lint */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <err.h>
+#include <fts.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <vis.h>
+#include <wchar.h>
+#include <wctype.h>
+
+#include "ls.h"
+#include "extern.h"
+
+int
+safe_print(const char *src)
+{
+	size_t len;
+	char *name;
+	int flags;
+
+	flags = VIS_NL | VIS_OCTAL | VIS_WHITE;
+	if (f_octal_escape)
+		flags |= VIS_CSTYLE;
+
+	len = strlen(src);
+	if (len != 0 && SIZE_T_MAX/len <= 4) {
+		errx(EXIT_FAILURE, "%s: name too long", src);
+		/* NOTREACHED */
+	}
+
+	name = (char *)malloc(4*len+1);
+	if (name != NULL) {
+		len = strvis(name, src, flags);
+		(void)printf("%s", name);
+		free(name);
+		return len;
+	} else
+		errx(EXIT_FAILURE, "out of memory!");
+		/* NOTREACHED */
+}
+
+/*
+ * The reasons why we don't use putwchar(wc) here are:
+ * - If wc == L'\0', we need to restore the initial shift state, but
+ *   the C language standard doesn't say that putwchar(L'\0') does.
+ * - It isn't portable to mix a wide-oriented function (i.e. getwchar)
+ *   with byte-oriented functions (printf et al.) in same FILE.
+ */
+static int
+printwc(wchar_t wc, mbstate_t *pst)
+{
+	size_t size;
+	char buf[MB_LEN_MAX];
+
+	size = wcrtomb(buf, wc, pst);
+	if (size == (size_t)-1) /* This shouldn't happen, but for sure */
+		return 0;
+	if (wc == L'\0') {
+		/* The following condition must be always true, but for sure */
+		if (size > 0 && buf[size - 1] == '\0')
+			--size;
+	}
+	if (size > 0)
+		fwrite(buf, 1, size, stdout);
+	return wc == L'\0' ? 0 : wcwidth(wc);
+}
+
+int
+printescaped(const char *src)
+{
+	int n = 0;
+	mbstate_t src_state, stdout_state;
+	/* The following +1 is to pass '\0' at the end of src to mbrtowc(). */
+	const char *endptr = src + strlen(src) + 1;
+
+	/*
+	 * We have to reset src_state each time in this function, because
+	 * the codeset of src pathname may not match with current locale.
+	 * Note that if we pass NULL instead of src_state to mbrtowc(),
+	 * there is no way to reset the state.
+	 */
+	memset(&src_state, 0, sizeof(src_state));
+	memset(&stdout_state, 0, sizeof(stdout_state));
+	while (src < endptr) {
+		wchar_t wc;
+		size_t rv, span = endptr - src;
+
+#if 0
+		/*
+		 * XXX - we should fix libc instead.
+		 * Theoretically this should work, but our current
+		 * implementation of iso2022 module doesn't actually work
+		 * as expected, if there are redundant escape sequences
+		 * which exceed 32 bytes.
+		 */
+		if (span > MB_CUR_MAX)
+			span = MB_CUR_MAX;
+#endif
+		rv = mbrtowc(&wc, src, span, &src_state);
+		if (rv == 0) { /* assert(wc == L'\0'); */
+			/* The following may output a shift sequence. */
+			n += printwc(wc, &stdout_state);
+			break;
+		}
+		if (rv == (size_t)-1) { /* probably errno == EILSEQ */
+			n += printwc(L'?', &stdout_state);
+			/* try to skip 1byte, because there is no better way */
+			src++;
+			memset(&src_state, 0, sizeof(src_state));
+		} else if (rv == (size_t)-2) {
+			if (span < MB_CUR_MAX) { /* incomplete char */
+				n += printwc(L'?', &stdout_state);
+				break;
+			}
+			src += span; /* a redundant shift sequence? */
+		} else {
+			n += printwc(iswprint(wc) ? wc : L'?', &stdout_state);
+			src += rv;
+		}
+	}
+	return n;
+}
--- a/apitue/sample-code/06/argv.c
+++ b/apitue/sample-code/06/argv.c
@ -0,0 +1,49 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* A simple program to show what arguments were passed to a program.  This
+ * can be used to illustrate how different shells expand arguments
+ * differently.
+ *
+ * See also:
+ * http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html
+ * https://wpollock.com/ShScript/CmdLineProcessing.htm
+ *
+ * Examples:
+ * ./a.out
+ * ./a.out *.c
+ * ./a.out *.none
+ * ./a.out *.[1c]
+ * ./a.out "*.c"
+ * ./a.out $USER
+ * ./a.out "$(echo *.1)"
+ * ./a.out {foo,bar,baz}.whatever
+ * ./a.out {1..5}
+ * ./a.out {1..5}{a..f}
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+int
+main(int argc, char **argv) {
+	int i;
+
+	for (i=0; i<argc; i++) {
+		printf("%s\n", argv[i]);
+	}
+
+	return EXIT_SUCCESS;
+}
--- a/apitue/sample-code/06/busy.c
+++ b/apitue/sample-code/06/busy.c
@ -0,0 +1,22 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+int main() {
+	int n;
+	while(1) {
+		n++;
+	}
+	return n;
+}
--- a/apitue/sample-code/06/checkpoint.c
+++ b/apitue/sample-code/06/checkpoint.c
@ -0,0 +1,46 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+int a;
+char *s;
+char buf[1024];
+
+int
+main(int argc, char **argv) {
+	int *b;
+	char *string = "abcd";
+
+	*b = 7;
+	printf("b at               : 0x%12lX\n", (unsigned long)&b);
+	printf("b at               : 0x%12lX\n", (unsigned long)&(*b));
+
+
+#if 0
+	printf("main (function) at : 0x%12lX\n", (unsigned long)&main);
+	printf("argc at            : 0x%12lX\n", (unsigned long)&argc);
+	printf("argv at            : 0x%12lX\n", (unsigned long)&argv);
+	printf("argv[0] at         : 0x%12lX\n", (unsigned long)&argv[0]);
+	printf("a at               : 0x%12lX\n", (unsigned long)&a);
+	printf("s at               : 0x%12lX\n", (unsigned long)&s);
+	printf("buf at             : 0x%12lX\n", (unsigned long)&buf);
+	printf("string at          : 0x%12lX\n", (unsigned long)&string);
+	printf("fixed string at    : 0x%12lX\n", (unsigned long)&(*string));
+#endif
+
+	return 0;
+}
--- a/apitue/sample-code/06/const.c
+++ b/apitue/sample-code/06/const.c
@ -0,0 +1,56 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/*
+ * Show the difference between placements of the const keyword.
+ *
+ * Note: you will get errors compiling this code.
+ */
+
+#include <stdio.h>
+
+char * const foo[] = {
+	"one",
+	"two",
+	"three",
+	NULL
+};
+
+const char *bar[] = {
+	"one",
+	"two",
+	"three",
+	NULL
+};
+
+int main() {
+
+	/* You can do this, because 'one' is not 'const'... */
+	foo[0][1] = 'w';
+
+	/* ...but your compiler will complain here, because the
+	 * 'foo' itself is 'const *'. */
+	foo[0] = "blah blah blah";
+
+	/* For 'bar', this is reversed: each element in the array
+	 * is const, so we can't change them... */
+	bar[0][1] = 'w';
+
+	/* ...but because 'bar' is not const, we can change what
+	 * this points to. */
+	bar[0] = "blah blah blah";
+
+	return 1;
+}
--- a/apitue/sample-code/06/entry.c
+++ b/apitue/sample-code/06/entry.c
@ -0,0 +1,65 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+/* This program can be used to illustrates how the kernel sets up the
+ * startup routine.  Call with "-e" to specify any of the functions as the
+ * entry point instead of 'main'; compare otool(1)/objdump(1) output and
+ * exit codes.
+ *
+ * To display the entry point of the program:
+ * NetBSD:
+ * - readelf -h a.out | grep ntry
+ * - objdump -d a.out
+ *
+ * Mac OS X:
+ * - otool -l a.out | grep ntry # decimal address
+ * - otool -v -t a.out          # hex address
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+int
+bar(void) {
+	printf("bar rules!\n");
+	exit(EXIT_FAILURE);
+	/* Unlike foo(), this will not cause a segfault, since we are not
+	 * returning; we explicitly call exit(3). */
+}
+
+int
+foo(void) {
+	printf("Foo for the win!\n");
+	return EXIT_FAILURE;
+	/* Note: this will cause a segfault on NetBSD, because this function
+	 * returns, but there is nothing to return to: the routines set up
+	 * by the kernel remain set up for 'main', we just told the linker
+	 * to jump into 'foo' at program start.  Compare objdump(1)
+	 * output.
+	 * Note: on OS X, we do not segfault! */
+}
+
+int
+main(int argc, char **argv) {
+	(void)argc;
+	(void)argv;
+	printf("main is at 0x%lX\n", (unsigned long)&main);
+	/* Note that we do explicitly _not_ return an error here, nor call
+	 * any of the exit(3) functions.  Your compiler may warn you
+	 * about this. We're also not casting the return value of printf(3)
+	 * to void. Inspect the return value. */
+}
--- a/apitue/sample-code/06/entry1.c
+++ b/apitue/sample-code/06/entry1.c
@ -0,0 +1,21 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+#include <stdio.h>
+
+int
+main(int argc, char **argv) {
+	printf("main is at 0x%lX\n", (unsigned long)&main);
+}
--- a/apitue/sample-code/06/entry2.c
+++ b/apitue/sample-code/06/entry2.c
@ -0,0 +1,28 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+int
+foo(void) {
+	(void)printf("Who needs 'main'?\n");
+	return EXIT_FAILURE;
+}
+
+int
+main(int argc, char **argv) {
+	printf("main is at 0x%lX\n", (unsigned long)&main);
+}
--- a/apitue/sample-code/06/entry3.c
+++ b/apitue/sample-code/06/entry3.c
@ -0,0 +1,34 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+int
+bar(void) {
+	(void)printf("Look, Ma: no main!\n");
+	exit(EXIT_FAILURE);
+}
+
+int
+foo(void) {
+	(void)printf("Who needs 'main'?\n");
+	return EXIT_FAILURE;
+}
+
+int
+main(int argc, char **argv) {
+	printf("main is at 0x%lX\n", (unsigned long)&main);
+}
--- a/apitue/sample-code/06/entry4.c
+++ b/apitue/sample-code/06/entry4.c
@ -0,0 +1,23 @@
+/* This file is part of the sample code and exercises
+ * used by the class "Advanced Programming in the UNIX
+ * Environment" taught by Jan Schaumann
+ * <jschauma@netmeister.org> at Stevens Institute of
+ * Technology.
+ *
+ * This file is in the public domain.
+ *
+ * You don't have to, but if you feel like
+ * acknowledging where you got this code, you may
+ * reference me by name, email address, or point
+ * people to the course website:
+ * https://stevens.netmeister.org/631/
+ */
+
+#include <stdio.h>
+
+int
+main() {
+	int n;
+	n = printf("main is at 0x%lX\n", (unsigned long)&main);
+	return n;
+}
--- a/Show More
+++ b/Show More