glibc/stdlib/test-dlclose-exit-race.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

93 lines
2.6 KiB
C

/* Test for exit/dlclose race (Bug 22180).
Copyright (C) 2017-2022 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/>. */
/* This file must be run from within a directory called "stdlib". */
/* This test verifies that when dlopen in one thread races against exit
in another thread, we don't call registered destructor twice.
Expected result:
second
first
... clean termination
*/
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <semaphore.h>
#include <support/check.h>
#include <support/xdlfcn.h>
#include <support/xthread.h>
/* Semaphore to ensure we have a happens-before between the first function
starting and exit being called. */
sem_t order1;
/* Semaphore to ensure we have a happens-before between the second function
starting and the first function returning. */
sem_t order2;
void *
exit_thread (void *arg)
{
/* Wait for the dlclose to start... */
sem_wait (&order1);
/* Then try to run the exit sequence which should call all
__cxa_atexit registered functions and in parallel with
the executing dlclose(). */
exit (0);
}
void
last (void)
{
/* Let dlclose thread proceed. */
sem_post (&order2);
}
int
main (void)
{
int value;
void *dso;
pthread_t thread;
atexit (last);
dso = xdlopen ("$ORIGIN/test-dlclose-exit-race-helper.so",
RTLD_NOW|RTLD_GLOBAL);
if ((value = pthread_create (&thread, NULL, exit_thread, NULL)) != 0)
{
/* If pthread_create fails, then exit() is called in the main
thread instead of a second thread, so the semaphore post that
would have happened in 'last' gets blocked behind the call to
first() - which is waiting on the semaphore, and thus
hangs. */
sem_post (&order2);
errno = value;
FAIL_EXIT1 ("pthread_create: %m");
}
xdlclose (dso);
xpthread_join (thread);
FAIL_EXIT1 ("Did not terminate via exit(0) in exit_thread() as expected.");
}