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Extend sem_trywait testing with a threaded test (RHEL-119403)

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Resolves: RHEL-119403
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Frédéric Bérat 2025-10-07 11:44:38 +02:00
parent fd242e7aae
commit 1c8abf48ab
1 changed files with 106 additions and 0 deletions
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@ -0,0 +1,106 @@
commit 3c2b9dc41cd05da055fae6f793a355063156bdf3
Author: Joseph Myers <josmyers@redhat.com>
Date: Fri Nov 29 20:25:04 2024 +0000
Add threaded test of sem_trywait
All the existing glibc tests of sem_trywait are single-threaded. Add
one that calls sem_trywait and sem_post in separate threads.
Tested for x86_64.
diff --git a/sysdeps/pthread/Makefile b/sysdeps/pthread/Makefile
index aef323296d7926f6..93a8534cbf814f27 100644
--- a/sysdeps/pthread/Makefile
+++ b/sysdeps/pthread/Makefile
@@ -257,6 +257,7 @@ tests += \
tst-sem15 \
tst-sem16 \
tst-sem18 \
+ tst-sem19 \
tst-setuid3 \
tst-signal1 \
tst-signal2 \
diff --git a/sysdeps/pthread/tst-sem19.c b/sysdeps/pthread/tst-sem19.c
new file mode 100644
index 0000000000000000..9ef461e008ab9eab
--- /dev/null
+++ b/sysdeps/pthread/tst-sem19.c
@@ -0,0 +1,77 @@
+/* Test sem_trywait with threads.
+ Copyright (C) 2024 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 <pthread.h>
+#include <semaphore.h>
+#include <support/check.h>
+#include <support/xthread.h>
+
+/* The test uses two threads, the main thread and a newly created
+ thread to test the operation of sem_trywait in a threaded scenario.
+ The intent is to test sem_trywait when it would return EAGAIN, and
+ then again after the critical section in the new thread has posted
+ to the semaphore and the main thread succeeds in calling
+ sem_trywait. It is possible this test fails with a timeout if the
+ second thread takes longer than the test timeout to acquire the
+ lock, and post. */
+
+static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
+static sem_t sem;
+
+static void *
+tf (void *arg)
+{
+ xpthread_mutex_lock (&lock);
+ sem_post (&sem);
+ xpthread_mutex_unlock (&lock);
+ return NULL;
+}
+
+static int
+do_test (void)
+{
+ int ret;
+
+ ret = sem_init (&sem, 0, 0);
+ TEST_VERIFY_EXIT (ret == 0);
+ xpthread_mutex_lock (&lock);
+ pthread_t th = xpthread_create (NULL, tf, NULL);
+ errno = 0;
+ /* The other thread is waiting on the lock before it calls sem_post,
+ so sem_trywait should fail. */
+ ret = sem_trywait (&sem);
+ TEST_COMPARE (ret, -1);
+ TEST_COMPARE (errno, EAGAIN);
+ xpthread_mutex_unlock (&lock);
+ /* The other thread now takes the lock, calls sem_post and releases
+ the lock. */
+ for (;;)
+ {
+ errno = 0;
+ ret = sem_trywait (&sem);
+ if (ret == 0)
+ break;
+ TEST_COMPARE (errno, EAGAIN);
+ }
+ xpthread_join (th);
+
+ return 0;
+}
+
+#include <support/test-driver.c>