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/* $OpenBSD: test-ping-pong.c,v 1.1 2019/11/09 21:10:15 anton Exp $ */
/*
* Copyright (c) 2019 Anton Lindqvist <anton@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <err.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "pipe.h"
/*
* Basic read/write test invovling two processes, P1 and P2. P1 writes "ping" on
* the pipe which is received and verified by P2. P2 writes "pong" as a reply
* which is received and verified P1. After N rounds, P1 closes the pipe and
* SIGPIPE is expected to be delivered to P2.
*/
int
test_ping_pong(void)
{
const char ping[] = "ping";
const char pong[] = "pong";
char buf[5];
int pip[2][2], rp, wp;
int nrounds = 10;
ssize_t n;
pid_t pid;
if (pipe(pip[0]) == -1)
err(1, "pipe");
if (pipe(pip[1]) == -1)
err(1, "pipe");
pid = fork();
if (pid == -1)
err(1, "fork");
if (pid == 0) {
rp = pip[0][0];
close(pip[0][1]);
wp = pip[1][1];
close(pip[1][0]);
for (;;) {
n = read(rp, buf, sizeof(buf));
if (n == -1)
err(1, "[c] read");
if (n == 0)
break;
if (n != sizeof(buf))
errx(1, "[c] read: %ld < %zu", n, sizeof(buf));
if (strcmp(ping, buf))
errx(1, "[c] read: %s != %s\n", ping, buf);
n = write(wp, pong, sizeof(pong));
if (n == -1)
err(1, "[c] write");
if (n != sizeof(pong))
errx(1, "[c] write: %ld < %zu", n, sizeof(pong));
nrounds--;
}
if (nrounds != 0)
errx(1, "[c] nrounds: %d > 0", nrounds);
/*
* Writing on the pipe must cause delivery of SIGPIPE at this
* point since the read end is gone.
*/
n = write(wp, pong, sizeof(pong));
if (n != -1)
errx(1, "[c] write: %ld != -1", n);
else if (errno != EPIPE)
errx(1, "[c] write: %d != %d", errno, EPIPE);
else if (!gotsigpipe)
errx(1, "[c] write: no SIGPIPE");
_exit(0);
} else {
rp = pip[1][0];
close(pip[1][1]);
wp = pip[0][1];
close(pip[0][0]);
for (;;) {
n = write(wp, ping, sizeof(ping));
if (n == -1)
err(1, "[p] write");
if (n != sizeof(ping))
errx(1, "[p] write: %ld < %zu", n, sizeof(ping));
n = read(rp, buf, sizeof(buf));
if (n == -1)
err(1, "[p] read");
if (n != sizeof(buf))
errx(1, "[p] read: %ld < %zu", n, sizeof(buf));
if (strcmp(pong, buf))
errx(1, "[p] read: %s != %s\n", pong, buf);
if (--nrounds == 0)
break;
}
/* Signal shutdown to the child. */
close(rp);
close(wp);
return xwaitpid(pid);
}
return 0;
}
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