posix/src/mutexunlock.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /**
0004  * @file
0005  *
0006  * @ingroup POSIXAPI
0007  *
0008  * @brief Locking and Unlocking a Mutex
0009  */
0010
0011 /*
0012  *  COPYRIGHT (c) 1989-2007.
0013  *  On-Line Applications Research Corporation (OAR).
0014  *
0015  * Redistribution and use in source and binary forms, with or without
0016  * modification, are permitted provided that the following conditions
0017  * are met:
0018  * 1. Redistributions of source code must retain the above copyright
0019  *    notice, this list of conditions and the following disclaimer.
0020  * 2. Redistributions in binary form must reproduce the above copyright
0021  *    notice, this list of conditions and the following disclaimer in the
0022  *    documentation and/or other materials provided with the distribution.
0023  *
0024  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0025  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0026  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0027  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0028  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0029  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0030  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0031  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0032  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0033  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0034  * POSSIBILITY OF SUCH DAMAGE.
0035  */
0036
0037 #ifdef HAVE_CONFIG_H
0038 #include "config.h"
0039 #endif
0040
0041 #include <rtems/posix/muteximpl.h>
0042 #include <rtems/posix/posixapi.h>
0043
0044 bool _POSIX_Mutex_Auto_initialization( POSIX_Mutex_Control *the_mutex )
0045 {
0046   unsigned long zero;
0047   unsigned long flags;
0048
0049   /* We cannot use memset() and memcmp() due to structure internal padding */
0050   zero = 0;
0051   zero |= the_mutex->flags;
0052 #if defined(RTEMS_SMP)
0053   zero |= _Atomic_Load_uint(
0054     &the_mutex->Recursive.Mutex.Queue.Queue.Lock.next_ticket,
0055     ATOMIC_ORDER_RELAXED
0056   );
0057   zero |= _Atomic_Load_uint(
0058     &the_mutex->Recursive.Mutex.Queue.Queue.Lock.now_serving,
0059     ATOMIC_ORDER_RELAXED
0060   );
0061 #else
0062   zero |= the_mutex->Recursive.Mutex.Queue.reserved[ 0 ];
0063   zero |= the_mutex->Recursive.Mutex.Queue.reserved[ 1 ];
0064 #endif
0065   zero |= (unsigned long) the_mutex->Recursive.Mutex.Queue.Queue.heads;
0066   zero |= (unsigned long) the_mutex->Recursive.Mutex.Queue.Queue.owner;
0067   zero |= (unsigned long) the_mutex->Recursive.Mutex.Queue.Queue.name;
0068   zero |= the_mutex->Recursive.nest_level;
0069   zero |= (unsigned long) the_mutex->Priority_ceiling.Node.RBTree.Node.rbe_left;
0070   zero |= (unsigned long) the_mutex->Priority_ceiling.Node.RBTree.Node.rbe_right;
0071   zero |= (unsigned long) the_mutex->Priority_ceiling.Node.RBTree.Node.rbe_parent;
0072   zero |= (unsigned long) the_mutex->Priority_ceiling.Node.RBTree.Node.rbe_color;
0073   zero |= (unsigned long) the_mutex->Priority_ceiling.priority;
0074   zero |= (unsigned long) (the_mutex->Priority_ceiling.priority >> 32);
0075   zero |= (unsigned long) the_mutex->scheduler;
0076
0077   if ( zero != 0 ) {
0078     return false;
0079   }
0080
0081   flags = (uintptr_t) the_mutex ^ POSIX_MUTEX_MAGIC;
0082   flags &= ~POSIX_MUTEX_FLAGS_MASK;
0083   the_mutex->flags = flags;
0084   return true;
0085 }
0086
0087 /*
0088  *  11.3.3 Locking and Unlocking a Mutex, P1003.1c/Draft 10, p. 93
0089  *
0090  *  NOTE: P1003.4b/D8 adds pthread_mutex_timedlock(), p. 29
0091  */
0092
0093 int pthread_mutex_unlock(
0094   pthread_mutex_t           *mutex
0095 )
0096 {
0097   POSIX_Mutex_Control  *the_mutex;
0098   unsigned long         flags;
0099   Thread_queue_Context  queue_context;
0100   Thread_Control       *executing;
0101   Status_Control        status;
0102
0103   the_mutex = _POSIX_Mutex_Get( mutex );
0104   POSIX_MUTEX_VALIDATE_OBJECT( the_mutex, flags );
0105
0106   executing = _POSIX_Mutex_Acquire( the_mutex, &queue_context );
0107
0108   switch ( _POSIX_Mutex_Get_protocol( flags ) ) {
0109     case POSIX_MUTEX_PRIORITY_CEILING:
0110       status = _POSIX_Mutex_Ceiling_surrender(
0111         the_mutex,
0112         executing,
0113         &queue_context
0114       );
0115       break;
0116     case POSIX_MUTEX_NO_PROTOCOL:
0117       status = _POSIX_Mutex_Surrender(
0118         the_mutex,
0119         POSIX_MUTEX_NO_PROTOCOL_TQ_OPERATIONS,
0120         executing,
0121         &queue_context
0122       );
0123       break;
0124     default:
0125       _Assert(
0126         _POSIX_Mutex_Get_protocol( flags ) == POSIX_MUTEX_PRIORITY_INHERIT
0127       );
0128       status = _POSIX_Mutex_Surrender(
0129         the_mutex,
0130         POSIX_MUTEX_PRIORITY_INHERIT_TQ_OPERATIONS,
0131         executing,
0132         &queue_context
0133       );
0134       break;
0135   }
0136
0137   return _POSIX_Get_error( status );
0138 }