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/*
* Semaphore Manager
*
* DESCRIPTION:
*
* This package is the implementation of the Semaphore Manager.
* This manager utilizes standard Dijkstra counting semaphores to provide
* synchronization and mutual exclusion capabilities.
*
* Directives provided are:
*
* + create a semaphore
* + get an ID of a semaphore
* + delete a semaphore
* + acquire a semaphore
* + release a semaphore
*
* COPYRIGHT (c) 1989-1999.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.OARcorp.com/rtems/license.html.
*
* $Id$
*/
#include <rtems/system.h>
#include <rtems/rtems/status.h>
#include <rtems/rtems/support.h>
#include <rtems/rtems/attr.h>
#include <rtems/score/isr.h>
#include <rtems/score/object.h>
#include <rtems/rtems/options.h>
#include <rtems/rtems/sem.h>
#include <rtems/score/coremutex.h>
#include <rtems/score/coresem.h>
#include <rtems/score/states.h>
#include <rtems/score/thread.h>
#include <rtems/score/threadq.h>
#if defined(RTEMS_MULTIPROCESSING)
#include <rtems/score/mpci.h>
#endif
#include <rtems/score/sysstate.h>
#include <rtems/score/interr.h>
/*PAGE
*
* rtems_semaphore_obtain
*
* This directive allows a thread to acquire a semaphore.
*
* Input parameters:
* id - semaphore id
* option_set - wait option
* timeout - number of ticks to wait (0 means wait forever)
*
* Output parameters:
* RTEMS_SUCCESSFUL - if successful
* error code - if unsuccessful
*/
rtems_status_code rtems_semaphore_obtain(
Objects_Id id,
unsigned32 option_set,
rtems_interval timeout
)
{
register Semaphore_Control *the_semaphore;
Objects_Locations location;
boolean wait;
the_semaphore = _Semaphore_Get( id, &location );
switch ( location ) {
case OBJECTS_REMOTE:
#if defined(RTEMS_MULTIPROCESSING)
return _Semaphore_MP_Send_request_packet(
SEMAPHORE_MP_OBTAIN_REQUEST,
id,
option_set,
timeout
);
#endif
case OBJECTS_ERROR:
return RTEMS_INVALID_ID;
case OBJECTS_LOCAL:
if ( _Options_Is_no_wait( option_set ) )
wait = FALSE;
else
wait = TRUE;
if ( _Attributes_Is_binary_semaphore( the_semaphore->attribute_set ) ) {
_CORE_mutex_Seize(
&the_semaphore->Core_control.mutex,
id,
wait,
timeout
);
_Thread_Enable_dispatch();
return _Semaphore_Translate_core_mutex_return_code(
_Thread_Executing->Wait.return_code );
} else {
_CORE_semaphore_Seize(
&the_semaphore->Core_control.semaphore,
id,
wait,
timeout
);
_Thread_Enable_dispatch();
return _Semaphore_Translate_core_semaphore_return_code(
_Thread_Executing->Wait.return_code );
}
}
return RTEMS_INTERNAL_ERROR; /* unreached - only to remove warnings */
}
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