From 529743d354ac402b1302b397159146fa46c180c5 Mon Sep 17 00:00:00 2001 From: julian Date: Mon, 22 Jan 1996 00:23:58 +0000 Subject: Reviewed by: julian Submitted by: john birrel One version of the pthreads library another will follow with differnt actions under some cases.. not QUITE complete --- lib/libpthread/thread/thr_mutex.c | 360 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 360 insertions(+) create mode 100644 lib/libpthread/thread/thr_mutex.c (limited to 'lib/libpthread/thread/thr_mutex.c') diff --git a/lib/libpthread/thread/thr_mutex.c b/lib/libpthread/thread/thr_mutex.c new file mode 100644 index 0000000..0fc9fbb --- /dev/null +++ b/lib/libpthread/thread/thr_mutex.c @@ -0,0 +1,360 @@ +/* + * Copyright (c) 1995 John Birrell . + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by John Birrell. + * 4. Neither the name of the author nor the names of any co-contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + */ +#include +#include +#ifdef _THREAD_SAFE +#include +#include "pthread_private.h" + +int +pthread_mutex_init(pthread_mutex_t * mutex, + const pthread_mutexattr_t * mutex_attr) +{ + enum pthread_mutextype type; + int ret = 0; + int status; + + /* Check if the mutex attributes specify some mutex other than fast: */ + if (mutex_attr != NULL && mutex_attr->m_type != MUTEX_TYPE_FAST) { + /* Check if the mutex type is out of range: */ + if (mutex_attr->m_type >= MUTEX_TYPE_MAX) { + /* Return an invalid argument error: */ + _thread_seterrno(_thread_run, EINVAL); + ret = -1; + } else { + /* Use the requested mutex type: */ + type = mutex_attr->m_type; + } + } else { + /* Default to a fast mutex: */ + type = MUTEX_TYPE_FAST; + } + + /* Check no errors so far: */ + if (ret == 0) { + /* Reset the mutex flags: */ + mutex->m_flags = 0; + + /* Block signals: */ + _thread_kern_sig_block(&status); + + /* Process according to mutex type: */ + switch (type) { + /* Fast mutex: */ + case MUTEX_TYPE_FAST: + /* Nothing to do here. */ + break; + + /* Counting mutex: */ + case MUTEX_TYPE_COUNTING_FAST: + /* Reset the mutex count: */ + mutex->m_data.m_count = 0; + break; + + /* Trap invalid mutex types: */ + default: + /* Return an invalid argument error: */ + _thread_seterrno(_thread_run, EINVAL); + ret = -1; + break; + } + + /* Initialise the rest of the mutex: */ + _thread_queue_init(&mutex->m_queue); + mutex->m_flags |= MUTEX_FLAGS_INITED; + mutex->m_owner = NULL; + mutex->m_type = type; + + /* Unblock signals: */ + _thread_kern_sig_unblock(status); + } + /* Return the completion status: */ + return (ret); +} + +int +pthread_mutex_destroy(pthread_mutex_t * mutex) +{ + int ret = 0; + int status; + + /* Block signals: */ + _thread_kern_sig_block(&status); + + /* Process according to mutex type: */ + switch (mutex->m_type) { + /* Fast mutex: */ + case MUTEX_TYPE_FAST: + /* Nothing to do here. */ + break; + + /* Counting mutex: */ + case MUTEX_TYPE_COUNTING_FAST: + /* Reset the mutex count: */ + mutex->m_data.m_count = 0; + break; + + /* Trap undefined mutex types: */ + default: + /* Return an invalid argument error: */ + _thread_seterrno(_thread_run, EINVAL); + ret = -1; + break; + } + + /* Clean up the mutex in case that others want to use it: */ + _thread_queue_init(&mutex->m_queue); + mutex->m_owner = NULL; + mutex->m_flags = 0; + + /* Unblock signals: */ + _thread_kern_sig_unblock(status); + + /* Return the completion status: */ + return (ret); +} + +int +pthread_mutex_trylock(pthread_mutex_t * mutex) +{ + int ret = 0; + int status; + + /* Block signals: */ + _thread_kern_sig_block(&status); + + /* Process according to mutex type: */ + switch (mutex->m_type) { + /* Fast mutex: */ + case MUTEX_TYPE_FAST: + /* Check if this mutex is not locked: */ + if (mutex->m_owner == NULL) { + /* Lock the mutex for the running thread: */ + mutex->m_owner = _thread_run; + } else { + /* Return a busy error: */ + _thread_seterrno(_thread_run, EBUSY); + ret = -1; + } + break; + + /* Counting mutex: */ + case MUTEX_TYPE_COUNTING_FAST: + /* Check if this mutex is locked: */ + if (mutex->m_owner != NULL) { + /* + * Check if the mutex is locked by the running + * thread: + */ + if (mutex->m_owner == _thread_run) { + /* Increment the lock count: */ + mutex->m_data.m_count++; + } else { + /* Return a busy error: */ + _thread_seterrno(_thread_run, EBUSY); + ret = -1; + } + } else { + /* Lock the mutex for the running thread: */ + mutex->m_owner = _thread_run; + } + break; + + /* Trap invalid mutex types: */ + default: + /* Return an invalid argument error: */ + _thread_seterrno(_thread_run, EINVAL); + ret = -1; + break; + } + + /* Unblock signals: */ + _thread_kern_sig_unblock(status); + + /* Return the completion status: */ + return (ret); +} + +int +pthread_mutex_lock(pthread_mutex_t * mutex) +{ + int ret = 0; + int status; + + /* Block signals: */ + _thread_kern_sig_block(&status); + + /* Process according to mutex type: */ + switch (mutex->m_type) { + /* Fast mutexes do not check for any error conditions: */ + case MUTEX_TYPE_FAST: + /* + * Enter a loop to wait for the mutex to be locked by the + * current thread: + */ + while (mutex->m_owner != _thread_run) { + /* Check if the mutex is not locked: */ + if (mutex->m_owner == NULL) { + /* Lock the mutex for this thread: */ + mutex->m_owner = _thread_run; + } else { + /* + * Join the queue of threads waiting to lock + * the mutex: + */ + _thread_queue_enq(&mutex->m_queue, _thread_run); + + /* Block signals: */ + _thread_kern_sched_state(PS_MUTEX_WAIT, __FILE__, __LINE__); + + /* Block signals: */ + _thread_kern_sig_block(NULL); + } + } + break; + + /* Counting mutex: */ + case MUTEX_TYPE_COUNTING_FAST: + /* + * Enter a loop to wait for the mutex to be locked by the + * current thread: + */ + while (mutex->m_owner != _thread_run) { + /* Check if the mutex is not locked: */ + if (mutex->m_owner == NULL) { + /* Lock the mutex for this thread: */ + mutex->m_owner = _thread_run; + + /* Reset the lock count for this mutex: */ + mutex->m_data.m_count = 0; + } else { + /* + * Join the queue of threads waiting to lock + * the mutex: + */ + _thread_queue_enq(&mutex->m_queue, _thread_run); + + /* Block signals: */ + _thread_kern_sched_state(PS_MUTEX_WAIT, __FILE__, __LINE__); + + /* Block signals: */ + _thread_kern_sig_block(NULL); + } + } + + /* Increment the lock count for this mutex: */ + mutex->m_data.m_count++; + break; + + /* Trap invalid mutex types: */ + default: + /* Return an invalid argument error: */ + _thread_seterrno(_thread_run, EINVAL); + ret = -1; + break; + } + + /* Unblock signals: */ + _thread_kern_sig_unblock(status); + + /* Return the completion status: */ + return (ret); +} + +int +pthread_mutex_unlock(pthread_mutex_t * mutex) +{ + int ret = 0; + int status; + + /* Block signals: */ + _thread_kern_sig_block(&status); + + /* Process according to mutex type: */ + switch (mutex->m_type) { + /* Fast mutexes do not check for any error conditions: */ + case MUTEX_TYPE_FAST: + /* Check if the running thread is not the owner of the mutex: */ + if (mutex->m_owner != _thread_run) { + /* Return an invalid argument error: */ + _thread_seterrno(_thread_run, EINVAL); + ret = -1; + } + /* + * Get the next thread from the queue of threads waiting on + * the mutex: + */ + else if ((mutex->m_owner = _thread_queue_deq(&mutex->m_queue)) != NULL) { + /* Allow the new owner of the mutex to run: */ + mutex->m_owner->state = PS_RUNNING; + } + break; + + /* Counting mutex: */ + case MUTEX_TYPE_COUNTING_FAST: + /* Check if the running thread is not the owner of the mutex: */ + if (mutex->m_owner != _thread_run) { + /* Return an invalid argument error: */ + _thread_seterrno(_thread_run, EINVAL); + ret = -1; + } + /* Check if there are still counts: */ + else if (mutex->m_data.m_count) { + /* Decrement the count: */ + mutex->m_data.m_count--; + } + /* + * Get the next thread from the queue of threads waiting on + * the mutex: + */ + else if ((mutex->m_owner = _thread_queue_deq(&mutex->m_queue)) != NULL) { + /* Allow the new owner of the mutex to run: */ + mutex->m_owner->state = PS_RUNNING; + } + break; + + /* Trap invalid mutex types: */ + default: + /* Return an invalid argument error: */ + _thread_seterrno(_thread_run, EINVAL); + ret = -1; + break; + } + + /* Unblock signals: */ + _thread_kern_sig_unblock(status); + + /* Return the completion status: */ + return (ret); +} +#endif -- cgit v1.1