forked from Imagelibrary/rtems
c090db7405
For semaphore object pointer and object validation see POSIX_SEMAPHORE_VALIDATE_OBJECT(). Destruction or close of a busy semaphore returns an error status. The object is not flushed. POSIX semaphores are now available in all configurations and no longer depend on --enable-posix. Update #2514. Update #3116.
88 lines
2.4 KiB
C
88 lines
2.4 KiB
C
/**
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* @file
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*
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* @brief Lock a Semaphore
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* @ingroup POSIX_SEMAPHORE POSIX Semaphores Support
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*/
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/*
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* COPYRIGHT (c) 1989-2008.
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* On-Line Applications Research Corporation (OAR).
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*
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* The license and distribution terms for this file may be
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* found in the file LICENSE in this distribution or at
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* http://www.rtems.org/license/LICENSE.
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*/
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#if HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <rtems/posix/semaphoreimpl.h>
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#include <rtems/score/todimpl.h>
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/*
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* 11.2.6 Lock a Semaphore, P1003.1b-1993, p.226
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*
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* NOTE: P1003.4b/D8 adds sem_timedwait(), p. 27
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*/
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int sem_timedwait(
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sem_t *__restrict _sem,
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const struct timespec *__restrict abstime
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)
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{
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Sem_Control *sem;
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Thread_queue_Context queue_context;
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ISR_Level level;
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Thread_Control *executing;
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unsigned int count;
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POSIX_SEMAPHORE_VALIDATE_OBJECT( _sem );
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sem = _Sem_Get( &_sem->_Semaphore );
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_Thread_queue_Context_initialize( &queue_context );
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_Thread_queue_Context_ISR_disable( &queue_context, level );
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executing = _Sem_Queue_acquire_critical( sem, &queue_context );
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count = sem->count;
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if ( __predict_true( count > 0 ) ) {
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sem->count = count - 1;
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_Sem_Queue_release( sem, level, &queue_context );
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return 0;
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} else {
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Watchdog_Interval ticks;
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Status_Control status;
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switch ( _TOD_Absolute_timeout_to_ticks( abstime, CLOCK_REALTIME, &ticks ) ) {
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case TOD_ABSOLUTE_TIMEOUT_INVALID:
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_Sem_Queue_release( sem, level, &queue_context );
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rtems_set_errno_and_return_minus_one( EINVAL );
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break;
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case TOD_ABSOLUTE_TIMEOUT_IS_IN_PAST:
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case TOD_ABSOLUTE_TIMEOUT_IS_NOW:
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_Sem_Queue_release( sem, level, &queue_context );
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rtems_set_errno_and_return_minus_one( ETIMEDOUT );
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break;
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default:
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break;
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}
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_Thread_queue_Context_set_thread_state(
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&queue_context,
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STATES_WAITING_FOR_SEMAPHORE
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);
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_Thread_queue_Context_set_do_nothing_enqueue_callout( &queue_context );
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_Thread_queue_Context_set_relative_timeout( &queue_context, ticks );
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_Thread_queue_Context_set_ISR_level( &queue_context, level );
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_Thread_queue_Enqueue(
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&sem->Queue.Queue,
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SEMAPHORE_TQ_OPERATIONS,
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executing,
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&queue_context
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);
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status = _Thread_Wait_get_status( executing );
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return _POSIX_Zero_or_minus_one_plus_errno( status );
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}
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}
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