glibc/posix/tst-vfork1.c

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/* Test for vfork functions.
Copyright (C) 2004-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2004.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
/* This test relies on non-POSIX functionality since the child
processes call write and getpid. */
static int
do_test (void)
{
int result = 0;
int fd[2];
if (pipe (fd) == -1)
{
puts ("pipe failed");
return 1;
}
/* First vfork() without previous getpid(). */
pid_t p1;
if ((p1 = vfork ()) == 0)
{
pid_t p = getpid ();
_exit (TEMP_FAILURE_RETRY (write (fd[1], &p, sizeof (p))) != sizeof (p));
}
else if (p1 == -1)
{
puts ("1st vfork failed");
result = 1;
}
pid_t p2 = 0;
if (TEMP_FAILURE_RETRY (read (fd[0], &p2, sizeof (pid_t))) != sizeof (pid_t))
{
puts ("1st read failed");
result = 1;
}
int r;
if (TEMP_FAILURE_RETRY (waitpid (p1, &r, 0)) != p1)
{
puts ("1st waitpid failed");
result = 1;
}
else if (r != 0)
{
puts ("write in 1st child failed");
result = 1;
}
/* Main process' ID. */
pid_t p0 = getpid ();
/* vfork() again, but after a getpid() in the main process. */
pid_t p3;
if ((p3 = vfork ()) == 0)
{
pid_t p = getpid ();
_exit (TEMP_FAILURE_RETRY (write (fd[1], &p, sizeof (p))) != sizeof (p));
}
else if (p1 == -1)
{
puts ("2nd vfork failed");
result = 1;
}
pid_t p4;
if (TEMP_FAILURE_RETRY (read (fd[0], &p4, sizeof (pid_t))) != sizeof (pid_t))
{
puts ("2nd read failed");
result = 1;
}
if (TEMP_FAILURE_RETRY (waitpid (p3, &r, 0)) != p3)
{
puts ("2nd waitpid failed");
result = 1;
}
else if (r != 0)
{
puts ("write in 2nd child failed");
result = 1;
}
/* And getpid in the main process again. */
pid_t p5 = getpid ();
/* Analysis of the results. */
if (p0 != p5)
{
printf ("p0(%ld) != p5(%ld)\n", (long int) p0, (long int) p5);
result = 1;
}
if (p0 == p1)
{
printf ("p0(%ld) == p1(%ld)\n", (long int) p0, (long int) p1);
result = 1;
}
if (p1 != p2)
{
printf ("p1(%ld) != p2(%ld)\n", (long int) p1, (long int) p2);
result = 1;
}
if (p0 == p3)
{
printf ("p0(%ld) == p3(%ld)\n", (long int) p0, (long int) p3);
result = 1;
}
if (p3 != p4)
{
printf ("p3(%ld) != p4(%ld)\n", (long int) p3, (long int) p4);
result = 1;
}
close (fd[0]);
close (fd[1]);
if (result == 0)
puts ("All OK");
return result;
}
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"