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/* Smoke test for the closefrom.
Copyright (C) 2021-2025 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
<https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <fcntl.h>
#include <sys/resource.h>
#include <unistd.h>
#include <support/check.h>
#include <support/descriptors.h>
#include <support/xunistd.h>
#include <support/support.h>
#include <array_length.h>
#define NFDS 100
static int
closefrom_test (void)
{
struct support_descriptors *descrs = support_descriptors_list ();
int lowfd = support_open_dev_null_range (NFDS, O_RDONLY, 0600);
const int maximum_fd = lowfd + NFDS - 1;
const int half_fd = lowfd + NFDS / 2;
const int gap = lowfd + NFDS / 4;
/* Close half of the descriptors and check result. */
closefrom (half_fd);
for (int i = half_fd; i <= maximum_fd; i++)
{
TEST_COMPARE (fcntl (i, F_GETFL), -1);
TEST_COMPARE (errno, EBADF);
}
for (int i = lowfd; i < half_fd; i++)
TEST_VERIFY (fcntl (i, F_GETFL) > -1);
/* Create some gaps, close up to a threshold, and check result. */
xclose (lowfd + 35);
xclose (lowfd + 38);
xclose (lowfd + 42);
xclose (lowfd + 46);
/* Close half of the descriptors and check result. */
closefrom (gap);
for (int i = gap + 1; i < maximum_fd; i++)
{
TEST_COMPARE (fcntl (i, F_GETFL), -1);
TEST_COMPARE (errno, EBADF);
}
for (int i = lowfd; i < gap; i++)
TEST_VERIFY (fcntl (i, F_GETFL) > -1);
/* Close the remmaining but the last one. */
closefrom (lowfd + 1);
for (int i = lowfd + 1; i <= maximum_fd; i++)
{
TEST_COMPARE (fcntl (i, F_GETFL), -1);
TEST_COMPARE (errno, EBADF);
}
TEST_VERIFY (fcntl (lowfd, F_GETFL) > -1);
/* Close the last one. */
closefrom (lowfd);
TEST_COMPARE (fcntl (lowfd, F_GETFL), -1);
TEST_COMPARE (errno, EBADF);
/* Double check by check the /proc. */
support_descriptors_check (descrs);
support_descriptors_free (descrs);
return 0;
}
/* Check if closefrom works even when no new file descriptors can be
created. */
static int
closefrom_test_file_desc_limit (void)
{
int max_fd = NFDS;
{
struct rlimit rl;
if (getrlimit (RLIMIT_NOFILE, &rl) == -1)
FAIL_EXIT1 ("getrlimit (RLIMIT_NOFILE): %m");
max_fd = (rl.rlim_cur < max_fd ? rl.rlim_cur : max_fd);
rl.rlim_cur = max_fd;
if (setrlimit (RLIMIT_NOFILE, &rl) == 1)
FAIL_EXIT1 ("setrlimit (RLIMIT_NOFILE): %m");
}
/* Exhauste the file descriptor limit. */
int lowfd = xopen ("/dev/null", O_RDONLY, 0600);
for (;;)
{
int fd = open ("/dev/null", O_RDONLY, 0600);
if (fd == -1)
{
if (errno != EMFILE)
FAIL_EXIT1 ("open: %m");
break;
}
TEST_VERIFY_EXIT (fd < max_fd);
}
closefrom (lowfd);
for (int i = lowfd; i < NFDS; i++)
{
TEST_COMPARE (fcntl (i, F_GETFL), -1);
TEST_COMPARE (errno, EBADF);
}
return 0;
}
static int
do_test (void)
{
closefrom_test ();
closefrom_test_file_desc_limit ();
return 0;
}
#include <support/test-driver.c>
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