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/*-
* Copyright (c) 2011 David Schultz
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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>
__FBSDID("$FreeBSD$");
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
/*
* BUFSIZE is the number of bytes of rc4 output to compare. The probability
* that this test fails spuriously is 2**(-BUFSIZE * 8).
*/
#define BUFSIZE 8
/*
* Test whether arc4random_buf() returns the same sequence of bytes in both
* parent and child processes. (Hint: It shouldn't.)
*/
int main(int argc, char *argv[]) {
struct shared_page {
char parentbuf[BUFSIZE];
char childbuf[BUFSIZE];
} *page;
pid_t pid;
char c;
printf("1..1\n");
page = mmap(NULL, sizeof(struct shared_page), PROT_READ | PROT_WRITE,
MAP_ANON | MAP_SHARED, -1, 0);
if (page == MAP_FAILED) {
printf("fail 1 - mmap\n");
exit(1);
}
arc4random_buf(&c, 1);
pid = fork();
if (pid < 0) {
printf("fail 1 - fork\n");
exit(1);
}
if (pid == 0) {
/* child */
arc4random_buf(page->childbuf, BUFSIZE);
exit(0);
} else {
/* parent */
int status;
arc4random_buf(page->parentbuf, BUFSIZE);
wait(&status);
}
if (memcmp(page->parentbuf, page->childbuf, BUFSIZE) == 0) {
printf("fail 1 - sequences are the same\n");
exit(1);
}
printf("ok 1 - sequences are different\n");
exit(0);
}
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