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/*
20140318
Jan Mojzis
Public domain.
*/
#include <stdio.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include "misc.h"
#include "randombytes.h"
static int verify(const unsigned char *x, const unsigned char *y) {
unsigned int i, d = 0;
for(i = 0; i < 16; ++i) d |= x[i] ^ y[i];
return (1 & ((d - 1) >> 8)) - 1;
}
static int readall(int fd, unsigned char *x, long long xlen) {
long long r;
while (xlen > 0) {
r = read(fd, x, xlen);
if (r <= 0) return -1;
x += r;
xlen -= r;
}
return 0;
}
static int writeall(int fd, unsigned char *x, long long xlen) {
long long r;
while (xlen > 0) {
r = write(fd, x, xlen);
if (r <= 0) return -1;
x += r;
xlen -= r;
}
return 0;
}
static void run(unsigned char *x, long long xlen) {
pid_t pid;
int status, fromchild[2];
unsigned char buf[16];
if (pipe(fromchild) == -1) fail("pipe() failure");
pid = fork();
if (pid == -1) fail("fork() failure");
if (pid == 0) {
close(fromchild[0]);
randombytes(buf, sizeof buf);
if (writeall(fromchild[1], buf, sizeof buf) == -1) _exit(111);
_exit(0);
}
close(fromchild[1]);
if (readall(fromchild[0], x, xlen) == -1) fail("read() failure");
while (waitpid(pid, &status, 0) != pid) {};
if (!WIFEXITED(status)) fail("process killed");
if (WEXITSTATUS(status)) fail("process exited with status != 0");
}
int main(void) {
unsigned char buf1[16];
unsigned char buf2[16];
run(buf1, sizeof buf1);
run(buf2, sizeof buf2);
if (verify(buf1, buf2) == 0) fail("randombytes() cryptographically dangerous");
randombytes(buf1, sizeof buf1);
randombytes(buf2, sizeof buf2);
if (verify(buf1, buf2) == 0) fail("randombytes() cryptographically dangerous");
run(buf1, sizeof buf1);
run(buf2, sizeof buf2);
if (verify(buf1, buf2) == 0) fail("randombytes() cryptographically dangerous across fork()");
_exit(0);
}
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