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/* Linuxthreads - a simple clone()-based implementation of Posix */
/* threads for Linux. */
/* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr) */
/* */
/* This program is free software; you can redistribute it and/or */
/* modify it under the terms of the GNU Library General Public License */
/* as published by the Free Software Foundation; either version 2 */
/* of the License, 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 Library General Public License for more details. */
/* Mutexes */
#include <errno.h>
#include <sched.h>
#include <stddef.h>
#include "pthread.h"
#include "internals.h"
#include "spinlock.h"
#include "queue.h"
#include "restart.h"
int __pthread_mutex_init(pthread_mutex_t * mutex,
const pthread_mutexattr_t * mutex_attr)
{
__pthread_init_lock(&mutex->__m_lock);
mutex->__m_kind =
mutex_attr == NULL ? PTHREAD_MUTEX_FAST_NP : mutex_attr->__mutexkind;
mutex->__m_count = 0;
mutex->__m_owner = NULL;
return 0;
}
strong_alias (__pthread_mutex_init, pthread_mutex_init)
int __pthread_mutex_destroy(pthread_mutex_t * mutex)
{
if (mutex->__m_lock.__status != 0) return EBUSY;
return 0;
}
strong_alias (__pthread_mutex_destroy, pthread_mutex_destroy)
int __pthread_mutex_trylock(pthread_mutex_t * mutex)
{
pthread_descr self;
int retcode;
switch(mutex->__m_kind) {
case PTHREAD_MUTEX_FAST_NP:
retcode = __pthread_trylock(&mutex->__m_lock);
return retcode;
case PTHREAD_MUTEX_RECURSIVE_NP:
self = thread_self();
if (mutex->__m_owner == self) {
mutex->__m_count++;
return 0;
}
retcode = __pthread_trylock(&mutex->__m_lock);
if (retcode == 0) {
mutex->__m_owner = self;
mutex->__m_count = 0;
}
return retcode;
case PTHREAD_MUTEX_ERRORCHECK_NP:
retcode = __pthread_trylock(&mutex->__m_lock);
if (retcode == 0) {
mutex->__m_owner = thread_self();
}
return retcode;
default:
return EINVAL;
}
}
strong_alias (__pthread_mutex_trylock, pthread_mutex_trylock)
int __pthread_mutex_lock(pthread_mutex_t * mutex)
{
pthread_descr self;
switch(mutex->__m_kind) {
case PTHREAD_MUTEX_FAST_NP:
__pthread_lock(&mutex->__m_lock, NULL);
return 0;
case PTHREAD_MUTEX_RECURSIVE_NP:
self = thread_self();
if (mutex->__m_owner == self) {
mutex->__m_count++;
return 0;
}
__pthread_lock(&mutex->__m_lock, self);
mutex->__m_owner = self;
mutex->__m_count = 0;
return 0;
case PTHREAD_MUTEX_ERRORCHECK_NP:
self = thread_self();
if (mutex->__m_owner == self) return EDEADLK;
__pthread_lock(&mutex->__m_lock, self);
mutex->__m_owner = self;
return 0;
default:
return EINVAL;
}
}
strong_alias (__pthread_mutex_lock, pthread_mutex_lock)
int __pthread_mutex_unlock(pthread_mutex_t * mutex)
{
switch (mutex->__m_kind) {
case PTHREAD_MUTEX_FAST_NP:
__pthread_unlock(&mutex->__m_lock);
return 0;
case PTHREAD_MUTEX_RECURSIVE_NP:
if (mutex->__m_count > 0) {
mutex->__m_count--;
return 0;
}
mutex->__m_owner = NULL;
__pthread_unlock(&mutex->__m_lock);
return 0;
case PTHREAD_MUTEX_ERRORCHECK_NP:
if (mutex->__m_owner != thread_self() || mutex->__m_lock.__status == 0)
return EPERM;
mutex->__m_owner = NULL;
__pthread_unlock(&mutex->__m_lock);
return 0;
default:
return EINVAL;
}
}
strong_alias (__pthread_mutex_unlock, pthread_mutex_unlock)
int __pthread_mutexattr_init(pthread_mutexattr_t *attr)
{
attr->__mutexkind = PTHREAD_MUTEX_FAST_NP;
return 0;
}
strong_alias (__pthread_mutexattr_init, pthread_mutexattr_init)
int __pthread_mutexattr_destroy(pthread_mutexattr_t *attr)
{
return 0;
}
strong_alias (__pthread_mutexattr_destroy, pthread_mutexattr_destroy)
int __pthread_mutexattr_settype(pthread_mutexattr_t *attr, int kind)
{
if (kind != PTHREAD_MUTEX_FAST_NP
&& kind != PTHREAD_MUTEX_RECURSIVE_NP
&& kind != PTHREAD_MUTEX_ERRORCHECK_NP)
return EINVAL;
attr->__mutexkind = kind;
return 0;
}
weak_alias (__pthread_mutexattr_settype, pthread_mutexattr_settype)
strong_alias ( __pthread_mutexattr_settype, __pthread_mutexattr_setkind_np)
weak_alias (__pthread_mutexattr_setkind_np, pthread_mutexattr_setkind_np)
int __pthread_mutexattr_gettype(const pthread_mutexattr_t *attr, int *kind)
{
*kind = attr->__mutexkind;
return 0;
}
weak_alias (__pthread_mutexattr_gettype, pthread_mutexattr_gettype)
strong_alias (__pthread_mutexattr_gettype, __pthread_mutexattr_getkind_np)
weak_alias (__pthread_mutexattr_getkind_np, pthread_mutexattr_getkind_np)
/* Once-only execution */
static pthread_mutex_t once_masterlock = PTHREAD_MUTEX_INITIALIZER;
static pthread_cond_t once_finished = PTHREAD_COND_INITIALIZER;
enum { NEVER = 0, IN_PROGRESS = 1, DONE = 2 };
/* If a thread is canceled while calling the init_routine out of
pthread once, this handler will reset the once_control variable
to the NEVER state. */
static void pthread_once_cancelhandler(void *arg)
{
pthread_once_t *once_control = arg;
pthread_mutex_lock(&once_masterlock);
*once_control = NEVER;
pthread_mutex_unlock(&once_masterlock);
pthread_cond_broadcast(&once_finished);
}
int __pthread_once(pthread_once_t * once_control, void (*init_routine)(void))
{
/* flag for doing the condition broadcast outside of mutex */
int state_changed;
/* Test without locking first for speed */
if (*once_control == DONE) return 0;
/* Lock and test again */
state_changed = 0;
pthread_mutex_lock(&once_masterlock);
/* If init_routine is being called from another routine, wait until
it completes. */
while (*once_control == IN_PROGRESS) {
pthread_cond_wait(&once_finished, &once_masterlock);
}
/* Here *once_control is stable and either NEVER or DONE. */
if (*once_control == NEVER) {
*once_control = IN_PROGRESS;
pthread_mutex_unlock(&once_masterlock);
pthread_cleanup_push(pthread_once_cancelhandler, once_control);
init_routine();
pthread_cleanup_pop(0);
pthread_mutex_lock(&once_masterlock);
*once_control = DONE;
state_changed = 1;
}
pthread_mutex_unlock(&once_masterlock);
if (state_changed)
pthread_cond_broadcast(&once_finished);
return 0;
}
strong_alias (__pthread_once, pthread_once)
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