rm_/lib/pthread-mutex.c

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2020-09-02 16:47:03 +08:00
/* POSIX mutexes (locks).
Copyright (C) 2010-2020 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, see <https://www.gnu.org/licenses/>. */
/* Written by Paul Eggert, 2010, and Bruno Haible <bruno@clisp.org>, 2019. */
#include <config.h>
/* Specification. */
#include <pthread.h>
#if (defined _WIN32 && ! defined __CYGWIN__) && USE_WINDOWS_THREADS
# include "windows-timedmutex.h"
# include "windows-timedrecmutex.h"
#else
# include <stdlib.h>
#endif
#if ((defined _WIN32 && ! defined __CYGWIN__) && USE_WINDOWS_THREADS) || !HAVE_PTHREAD_H
int
pthread_mutexattr_init (pthread_mutexattr_t *attr)
{
*attr = (PTHREAD_MUTEX_STALLED << 2) | PTHREAD_MUTEX_DEFAULT;
return 0;
}
int
pthread_mutexattr_gettype (const pthread_mutexattr_t *attr, int *typep)
{
*typep = *attr & (PTHREAD_MUTEX_DEFAULT | PTHREAD_MUTEX_NORMAL
| PTHREAD_MUTEX_ERRORCHECK | PTHREAD_MUTEX_RECURSIVE);
return 0;
}
int
pthread_mutexattr_settype (pthread_mutexattr_t *attr, int type)
{
if (!(type == PTHREAD_MUTEX_DEFAULT
|| type == PTHREAD_MUTEX_NORMAL
|| type == PTHREAD_MUTEX_ERRORCHECK
|| type == PTHREAD_MUTEX_RECURSIVE))
return EINVAL;
*attr ^= (*attr ^ type)
& (PTHREAD_MUTEX_DEFAULT | PTHREAD_MUTEX_NORMAL
| PTHREAD_MUTEX_ERRORCHECK | PTHREAD_MUTEX_RECURSIVE);
return 0;
}
int
pthread_mutexattr_getrobust (const pthread_mutexattr_t *attr, int *robustp)
{
*robustp = (*attr >> 2) & (PTHREAD_MUTEX_STALLED | PTHREAD_MUTEX_ROBUST);
return 0;
}
int
pthread_mutexattr_setrobust (pthread_mutexattr_t *attr, int robust)
{
if (!(robust == PTHREAD_MUTEX_STALLED || robust == PTHREAD_MUTEX_ROBUST))
return EINVAL;
*attr ^= (*attr ^ (robust << 2))
& ((PTHREAD_MUTEX_STALLED | PTHREAD_MUTEX_ROBUST) << 2);
return 0;
}
int
pthread_mutexattr_destroy (pthread_mutexattr_t *attr _GL_UNUSED)
{
return 0;
}
#elif PTHREAD_MUTEXATTR_ROBUST_UNIMPLEMENTED
int
pthread_mutexattr_getrobust (const pthread_mutexattr_t *attr, int *robustp)
{
*robustp = PTHREAD_MUTEX_STALLED;
return 0;
}
int
pthread_mutexattr_setrobust (pthread_mutexattr_t *attr, int robust)
{
if (!(robust == PTHREAD_MUTEX_STALLED || robust == PTHREAD_MUTEX_ROBUST))
return EINVAL;
if (!(robust == PTHREAD_MUTEX_STALLED))
return ENOTSUP;
return 0;
}
#endif
#if (defined _WIN32 && ! defined __CYGWIN__) && USE_WINDOWS_THREADS
/* Use Windows threads. */
int
pthread_mutex_init (pthread_mutex_t *mutex, const pthread_mutexattr_t *attr)
{
/* This implementation does not support PTHREAD_MUTEX_ERRORCHECK
and ignores the 'robust' attribute. */
if (attr != NULL
&& (*attr & (PTHREAD_MUTEX_DEFAULT | PTHREAD_MUTEX_NORMAL
| PTHREAD_MUTEX_ERRORCHECK | PTHREAD_MUTEX_RECURSIVE))
== PTHREAD_MUTEX_RECURSIVE)
{
mutex->type = 2;
return glwthread_timedrecmutex_init (&mutex->u.u_timedrecmutex);
}
else
{
mutex->type = 1;
return glwthread_timedmutex_init (&mutex->u.u_timedmutex);
}
}
int
pthread_mutex_lock (pthread_mutex_t *mutex)
{
switch (mutex->type)
{
case 1:
return glwthread_timedmutex_lock (&mutex->u.u_timedmutex);
case 2:
return glwthread_timedrecmutex_lock (&mutex->u.u_timedrecmutex);
default:
abort ();
}
}
int
pthread_mutex_trylock (pthread_mutex_t *mutex)
{
switch (mutex->type)
{
case 1:
return glwthread_timedmutex_trylock (&mutex->u.u_timedmutex);
case 2:
return glwthread_timedrecmutex_trylock (&mutex->u.u_timedrecmutex);
default:
abort ();
}
}
int
pthread_mutex_timedlock (pthread_mutex_t *mutex, const struct timespec *abstime)
{
switch (mutex->type)
{
case 1:
return glwthread_timedmutex_timedlock (&mutex->u.u_timedmutex, abstime);
case 2:
return glwthread_timedrecmutex_timedlock (&mutex->u.u_timedrecmutex,
abstime);
default:
abort ();
}
}
int
pthread_mutex_unlock (pthread_mutex_t *mutex)
{
switch (mutex->type)
{
case 1:
return glwthread_timedmutex_unlock (&mutex->u.u_timedmutex);
case 2:
return glwthread_timedrecmutex_unlock (&mutex->u.u_timedrecmutex);
default:
abort ();
}
}
int
pthread_mutex_destroy (pthread_mutex_t *mutex)
{
switch (mutex->type)
{
case 1:
return glwthread_timedmutex_destroy (&mutex->u.u_timedmutex);
case 2:
return glwthread_timedrecmutex_destroy (&mutex->u.u_timedrecmutex);
default:
abort ();
}
}
#elif HAVE_PTHREAD_H
/* Provide workarounds for POSIX threads. */
/* pthread_mutex_timedlock is defined by the 'pthread_mutex_timedlock'
module. */
#else
/* Provide a dummy implementation for single-threaded applications. */
int
pthread_mutex_init (pthread_mutex_t *mutex _GL_UNUSED,
const pthread_mutexattr_t *attr _GL_UNUSED)
{
/* MUTEX is never seriously used. */
return 0;
}
int
pthread_mutex_lock (pthread_mutex_t *mutex _GL_UNUSED)
{
/* There is only one thread, so it always gets the lock. This
implementation does not support PTHREAD_MUTEX_ERRORCHECK. */
return 0;
}
int
pthread_mutex_trylock (pthread_mutex_t *mutex _GL_UNUSED)
{
/* There is only one thread, so it always gets the lock. This
implementation does not support PTHREAD_MUTEX_ERRORCHECK. */
return 0;
}
int
pthread_mutex_timedlock (pthread_mutex_t *mutex _GL_UNUSED,
const struct timespec *abstime _GL_UNUSED)
{
/* There is only one thread, so it always gets the lock. This
implementation does not support PTHREAD_MUTEX_ERRORCHECK. */
return 0;
}
int
pthread_mutex_unlock (pthread_mutex_t *mutex _GL_UNUSED)
{
/* There is only one thread, so it always unlocks successfully.
This implementation does not support robust mutexes or
PTHREAD_MUTEX_ERRORCHECK. */
return 0;
}
int
pthread_mutex_destroy (pthread_mutex_t *mutex _GL_UNUSED)
{
/* MUTEX is never seriously used. */
return 0;
}
#endif