glibc/sysdeps/unix/sysv/linux/tst-o_path-locks.c
Paul Eggert 581c785bf3 Update copyright dates with scripts/update-copyrights
I used these shell commands:

../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")

and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 7061 files FOO.

I then removed trailing white space from math/tgmath.h,
support/tst-support-open-dev-null-range.c, and
sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following
obscure pre-commit check failure diagnostics from Savannah.  I don't
know why I run into these diagnostics whereas others evidently do not.

remote: *** 912-#endif
remote: *** 913:
remote: *** 914-
remote: *** error: lines with trailing whitespace found
...
remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
2022-01-01 11:40:24 -08:00

101 lines
2.8 KiB
C

/* Test that closing O_PATH descriptors does not release POSIX advisory locks.
Copyright (C) 2020-2022 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 <stdbool.h>
#include <stdlib.h>
#include <support/check.h>
#include <support/namespace.h>
#include <support/support.h>
#include <support/temp_file.h>
#include <support/xunistd.h>
/* The subprocess writes the errno value of the lock operation
here. */
static int *shared_errno;
/* The path of the temporary file which is locked. */
static char *path;
/* Try to obtain an exclusive lock on the file at path. */
static void
subprocess (void *closure)
{
int fd = xopen (path, O_RDWR, 0);
struct flock64 lock = { .l_type = F_WRLCK, };
int ret = fcntl64 (fd, F_SETLK, &lock);
if (ret == 0)
*shared_errno = 0;
else
*shared_errno = errno;
xclose (fd);
}
/* Return true if the file at path is currently locked, false if
not. */
static bool
probe_lock (void)
{
*shared_errno = -1;
support_isolate_in_subprocess (subprocess, NULL);
if (*shared_errno == 0)
/* Lock was aquired by the subprocess, so this process has not
locked it. */
return false;
else
{
/* POSIX allows both EACCES and EAGAIN. Linux use EACCES. */
TEST_COMPARE (*shared_errno, EAGAIN);
return true;
}
}
static int
do_test (void)
{
shared_errno = support_shared_allocate (sizeof (*shared_errno));
int fd = create_temp_file ("tst-o_path-locks-", &path);
/* The file is not locked initially. */
TEST_VERIFY (!probe_lock ());
struct flock64 lock = { .l_type = F_WRLCK, };
TEST_COMPARE (fcntl64 (fd, F_SETLK, &lock), 0);
/* The lock has been acquired. */
TEST_VERIFY (probe_lock ());
/* Closing the same file via a different descriptor releases the
lock. */
xclose (xopen (path, O_RDONLY, 0));
TEST_VERIFY (!probe_lock ());
/* But not if it is an O_PATH descriptor. */
TEST_COMPARE (fcntl64 (fd, F_SETLK, &lock), 0);
xclose (xopen (path, O_PATH, 0));
TEST_VERIFY (probe_lock ());
xclose (fd);
free (path);
support_shared_free (shared_errno);
return 0;
}
#include <support/test-driver.c>