180 lines
3.4 KiB
C
180 lines
3.4 KiB
C
/* 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 shows how we can combine select(2) and
|
|
* a per-connection fork(2) model to handle
|
|
* simultaneous connections in a typical server setup.
|
|
*/
|
|
#include <arpa/inet.h>
|
|
|
|
#include <sys/types.h>
|
|
#include <sys/socket.h>
|
|
#include <sys/time.h>
|
|
#include <sys/wait.h>
|
|
|
|
#include <netinet/in.h>
|
|
|
|
#include <errno.h>
|
|
#include <netdb.h>
|
|
#include <signal.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <unistd.h>
|
|
|
|
#define BACKLOG 5
|
|
|
|
#ifndef SLEEP
|
|
#define SLEEP 5
|
|
#endif
|
|
|
|
int
|
|
createSocket(void)
|
|
{
|
|
int sock;
|
|
socklen_t length;
|
|
struct sockaddr_in6 server;
|
|
|
|
memset(&server, 0, sizeof(server));
|
|
|
|
if ((sock = socket(PF_INET6, SOCK_STREAM, 0)) < 0) {
|
|
perror("opening stream socket");
|
|
exit(EXIT_FAILURE);
|
|
/* NOTREACHED */
|
|
}
|
|
|
|
server.sin6_family = PF_INET6;
|
|
server.sin6_addr = in6addr_any;
|
|
server.sin6_port = 0;
|
|
if (bind(sock, (struct sockaddr *)&server, sizeof(server)) != 0) {
|
|
perror("binding stream socket");
|
|
exit(EXIT_FAILURE);
|
|
/* NOTREACHED */
|
|
}
|
|
|
|
length = sizeof(server);
|
|
if (getsockname(sock, (struct sockaddr *)&server, &length) != 0) {
|
|
perror("getting socket name");
|
|
exit(EXIT_FAILURE);
|
|
/* NOTREACHED */
|
|
}
|
|
(void)printf("Socket has port #%d\n", ntohs(server.sin6_port));
|
|
|
|
if (listen(sock, BACKLOG) < 0) {
|
|
perror("listening");
|
|
exit(EXIT_FAILURE);
|
|
/* NOTREACHED */
|
|
}
|
|
|
|
return sock;
|
|
}
|
|
|
|
void
|
|
handleConnection(int fd, struct sockaddr_in6 client)
|
|
{
|
|
const char *rip;
|
|
int rval;
|
|
char claddr[INET6_ADDRSTRLEN];
|
|
|
|
if ((rip = inet_ntop(PF_INET6, &(client.sin6_addr), claddr, INET6_ADDRSTRLEN)) == NULL) {
|
|
perror("inet_ntop");
|
|
rip = "unknown";
|
|
} else {
|
|
(void)printf("Client connection from %s!\n", rip);
|
|
}
|
|
|
|
do {
|
|
char buf[BUFSIZ];
|
|
bzero(buf, sizeof(buf));
|
|
if ((rval = read(fd, buf, BUFSIZ)) < 0)
|
|
perror("reading stream message");
|
|
else if (rval == 0)
|
|
printf("Ending connection from %s.\n", rip);
|
|
else
|
|
printf("Client (%s) sent: %s", rip, buf);
|
|
} while (rval != 0);
|
|
(void)close(fd);
|
|
exit(EXIT_SUCCESS);
|
|
/* NOTREACHED */
|
|
}
|
|
void
|
|
handleSocket(int s)
|
|
{
|
|
int fd;
|
|
pid_t pid;
|
|
struct sockaddr_in6 client;
|
|
socklen_t length;
|
|
|
|
memset(&client, 0, sizeof(client));
|
|
|
|
length = sizeof(client);
|
|
if ((fd = accept(s, (struct sockaddr *)&client, &length)) < 0) {
|
|
perror("accept");
|
|
return;
|
|
}
|
|
|
|
if ((pid = fork()) < 0) {
|
|
perror("fork");
|
|
exit(EXIT_FAILURE);
|
|
/* NOTREACHED */
|
|
} else if (!pid) {
|
|
handleConnection(fd, client);
|
|
/* NOTREACHED */
|
|
}
|
|
/* parent silently returns */
|
|
}
|
|
|
|
void
|
|
reap() {
|
|
wait(NULL);
|
|
}
|
|
|
|
int
|
|
main()
|
|
{
|
|
int s1;
|
|
|
|
if (signal(SIGCHLD, reap) == SIG_ERR) {
|
|
perror("signal");
|
|
exit(EXIT_FAILURE);
|
|
/* NOTREACHED */
|
|
}
|
|
|
|
s1 = createSocket();
|
|
|
|
for (;;) {
|
|
fd_set ready;
|
|
struct timeval to;
|
|
|
|
FD_ZERO(&ready);
|
|
FD_SET(s1, &ready);
|
|
to.tv_sec = SLEEP;
|
|
to.tv_usec = 0;
|
|
if (select(s1 + 1, &ready, 0, 0, &to) < 0) {
|
|
if (errno != EINTR) {
|
|
perror("select");
|
|
}
|
|
continue;
|
|
}
|
|
if (FD_ISSET(s1, &ready)) {
|
|
handleSocket(s1);
|
|
} else {
|
|
(void)printf("Idly sitting here, waiting for connections...\n");
|
|
}
|
|
}
|
|
|
|
/* NOTREACHED */
|
|
}
|