54 lines
1.2 KiB
C
54 lines
1.2 KiB
C
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/* This file is part of the sample code and exercises
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* used by the class "Advanced Programming in the UNIX
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* Environment" taught by Jan Schaumann
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* <jschauma@netmeister.org> at Stevens Institute of
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* Technology.
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*
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* This file is in the public domain.
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*
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* You don't have to, but if you feel like
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* acknowledging where you got this code, you may
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* reference me by name, email address, or point
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* people to the course website:
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* https://stevens.netmeister.org/631/
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*/
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/* A simple program to introduce the concept of shared libraries.
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*
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* Compiling this program will work, as we have the forward declaration
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* from the header. Linking the executable will fail,
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* unless we explicitly link against libcrypto.
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*
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* Compare also:
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* cc -Wall rand.c -lcrypto
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* cc -Wall -rdynamic dlopenex.c
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*/
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#include <openssl/rand.h>
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#include <err.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#define NUM 16
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int
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main(int argc, char **argv) {
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int i;
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unsigned char data[NUM];
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if (RAND_bytes(data, NUM) == 0) {
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err(EXIT_FAILURE, "Unable to generate random data: %s\n",
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strerror(errno));
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/* NOTREACHED */
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}
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for (i=0; i<NUM; i++) {
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(void)printf("%02X", data[i]);
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}
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(void)printf("\n");
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exit(EXIT_SUCCESS);
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}
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