mirror of
https://sourceware.org/git/glibc.git
synced 2025-10-30 10:45:40 +03:00
117 lines
2.9 KiB
C
117 lines
2.9 KiB
C
/* Copyright (C) 2015-2017 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/>. */
|
|
|
|
/* This tests that a writer that is preferred -- but times out due to a
|
|
reader being present -- does not miss to wake other readers blocked on the
|
|
writer's pending lock acquisition. */
|
|
|
|
#include <errno.h>
|
|
#include <pthread.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <time.h>
|
|
|
|
/* The bug existed in the code that strictly prefers writers over readers. */
|
|
static pthread_rwlock_t r = PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP;
|
|
|
|
static void *
|
|
writer (void *arg)
|
|
{
|
|
struct timespec ts;
|
|
if (clock_gettime (CLOCK_REALTIME, &ts) != 0)
|
|
{
|
|
puts ("clock_gettime failed");
|
|
exit (EXIT_FAILURE);
|
|
}
|
|
ts.tv_sec += 1;
|
|
int e = pthread_rwlock_timedwrlock (&r, &ts);
|
|
if (e != ETIMEDOUT)
|
|
{
|
|
puts ("timedwrlock did not time out");
|
|
exit (EXIT_FAILURE);
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
static void *
|
|
reader (void *arg)
|
|
{
|
|
/* This isn't a reliable way to get the interleaving we need (because a
|
|
failed trylock doesn't synchronize with the writer, and because we could
|
|
try to lock after the writer has already timed out). However, both will
|
|
just lead to false positives. */
|
|
int e;
|
|
while ((e = pthread_rwlock_tryrdlock (&r)) != EBUSY)
|
|
{
|
|
if (e != 0)
|
|
exit (EXIT_FAILURE);
|
|
pthread_rwlock_unlock (&r);
|
|
}
|
|
e = pthread_rwlock_rdlock (&r);
|
|
if (e != 0)
|
|
{
|
|
puts ("reader rdlock failed");
|
|
exit (EXIT_FAILURE);
|
|
}
|
|
pthread_rwlock_unlock (&r);
|
|
return NULL;
|
|
}
|
|
|
|
|
|
static int
|
|
do_test (void)
|
|
{
|
|
/* Grab a rdlock, then create a writer and a reader, and wait until they
|
|
finished. */
|
|
|
|
if (pthread_rwlock_rdlock (&r) != 0)
|
|
{
|
|
puts ("initial rdlock failed");
|
|
return 1;
|
|
}
|
|
|
|
pthread_t thw;
|
|
if (pthread_create (&thw, NULL, writer, NULL) != 0)
|
|
{
|
|
puts ("create failed");
|
|
return 1;
|
|
}
|
|
pthread_t thr;
|
|
if (pthread_create (&thr, NULL, reader, NULL) != 0)
|
|
{
|
|
puts ("create failed");
|
|
return 1;
|
|
}
|
|
|
|
if (pthread_join (thw, NULL) != 0)
|
|
{
|
|
puts ("writer join failed");
|
|
return 1;
|
|
}
|
|
if (pthread_join (thr, NULL) != 0)
|
|
{
|
|
puts ("reader join failed");
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
#define TEST_FUNCTION do_test ()
|
|
#include "../test-skeleton.c"
|