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sysconf: Use conservative default for _SC_NPROCESSORS_ONLN [BZ #21542]

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This commit is contained in:
Florian Weimer
2017-07-04 16:12:46 +02:00
parent 4446a885f3
commit 1ff6c67a25
4 changed files with 109 additions and 2 deletions
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95
posix/tst-sysconf-empty-chroot.c Normal file
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/* Test sysconf with an empty chroot.
Copyright (C) 2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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 <stdio.h>
#include <stdlib.h>
#include <support/check.h>
#include <support/namespace.h>
#include <support/support.h>
#include <support/temp_file.h>
#include <support/test-driver.h>
#include <support/xunistd.h>
#include <unistd.h>
/* Check for an SMP system in a forked process, so that the parent
process does not cache the value. */
static void
is_smp_callback (void *closure)
{
bool *result = closure;
long cpus = sysconf (_SC_NPROCESSORS_ONLN);
TEST_VERIFY_EXIT (cpus > 0);
*result = cpus != 1;
}
static bool
is_smp (void)
{
bool *result = support_shared_allocate (sizeof (*result));
support_isolate_in_subprocess (is_smp_callback, result);
bool result_copy = *result;
support_shared_free (result);
return result_copy;
}
static char *path_chroot;
/* Prepare an empty directory, to be used as a chroot. */
static void
prepare (int argc, char **argv)
{
path_chroot = xasprintf ("%s/tst-resolv-res_init-XXXXXX", test_dir);
if (mkdtemp (path_chroot) == NULL)
FAIL_EXIT1 ("mkdtemp (\"%s\"): %m", path_chroot);
add_temp_file (path_chroot);
}
/* The actual test. Run it in a subprocess, so that the test harness
can remove the temporary directory in --direct mode. */
static void
chroot_callback (void *closure)
{
xchroot (path_chroot);
long cpus = sysconf (_SC_NPROCESSORS_ONLN);
printf ("info: sysconf (_SC_NPROCESSORS_ONLN) in chroot: %ld\n", cpus);
TEST_VERIFY (cpus > 0);
TEST_VERIFY (cpus != 1);
_exit (0);
}
static int
do_test (void)
{
if (!is_smp ())
{
printf ("warning: test not supported on uniprocessor system\n");
return EXIT_UNSUPPORTED;
}
support_become_root ();
if (!support_can_chroot ())
return EXIT_UNSUPPORTED;
support_isolate_in_subprocess (chroot_callback, NULL);
return 0;
}
#define PREPARE prepare
#include <support/test-driver.c>