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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_create
*
* This directive creates a semaphore and sets the initial value based
* on the given count. A semaphore id is returned.
*
* Input parameters:
* name - user defined semaphore name
* count - initial count of semaphore
* attribute_set - semaphore attributes
* priority_ceiling - semaphore's ceiling priority
* id - pointer to semaphore id
*
* Output parameters:
* id - semaphore id
* RTEMS_SUCCESSFUL - if successful
* error code - if unsuccessful
*/
rtems_status_code rtems_semaphore_create(
rtems_name name,
unsigned32 count,
rtems_attribute attribute_set,
rtems_task_priority priority_ceiling,
Objects_Id *id
)
{
register Semaphore_Control *the_semaphore;
CORE_mutex_Attributes the_mutex_attributes;
CORE_semaphore_Attributes the_semaphore_attributes;
unsigned32 lock;
if ( !rtems_is_name_valid( name ) )
return RTEMS_INVALID_NAME;
#if defined(RTEMS_MULTIPROCESSING)
if ( _Attributes_Is_global( attribute_set ) ) {
if ( !_System_state_Is_multiprocessing )
return RTEMS_MP_NOT_CONFIGURED;
if ( _Attributes_Is_inherit_priority( attribute_set ) )
return RTEMS_NOT_DEFINED;
} else
#endif
if ( _Attributes_Is_inherit_priority( attribute_set ) ||
_Attributes_Is_priority_ceiling( attribute_set ) ) {
if ( ! ( (_Attributes_Is_binary_semaphore( attribute_set ) ||
_Attributes_Is_simple_binary_semaphore( attribute_set )) &&
_Attributes_Is_priority( attribute_set ) ) )
return RTEMS_NOT_DEFINED;
}
if ( !_Attributes_Is_counting_semaphore( attribute_set ) && ( count > 1 ) )
return RTEMS_INVALID_NUMBER;
_Thread_Disable_dispatch(); /* prevents deletion */
the_semaphore = _Semaphore_Allocate();
if ( !the_semaphore ) {
_Thread_Enable_dispatch();
return RTEMS_TOO_MANY;
}
#if defined(RTEMS_MULTIPROCESSING)
if ( _Attributes_Is_global( attribute_set ) &&
! ( _Objects_MP_Allocate_and_open( &_Semaphore_Information, name,
the_semaphore->Object.id, FALSE ) ) ) {
_Semaphore_Free( the_semaphore );
_Thread_Enable_dispatch();
return RTEMS_TOO_MANY;
}
#endif
the_semaphore->attribute_set = attribute_set;
/*
* If it is not a counting semaphore, then it is either a
* simple binary semaphore or a more powerful mutex style binary
* semaphore.
*/
if ( !_Attributes_Is_counting_semaphore( attribute_set ) ) {
if ( _Attributes_Is_inherit_priority( attribute_set ) )
the_mutex_attributes.discipline = CORE_MUTEX_DISCIPLINES_PRIORITY_INHERIT;
else if ( _Attributes_Is_priority_ceiling( attribute_set ) )
the_mutex_attributes.discipline = CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING;
else if ( _Attributes_Is_priority( attribute_set ) )
the_mutex_attributes.discipline = CORE_MUTEX_DISCIPLINES_PRIORITY;
else
the_mutex_attributes.discipline = CORE_MUTEX_DISCIPLINES_FIFO;
if ( _Attributes_Is_binary_semaphore( attribute_set ) ) {
the_mutex_attributes.lock_nesting_behavior = CORE_MUTEX_NESTING_ACQUIRES;
switch ( the_mutex_attributes.discipline ) {
case CORE_MUTEX_DISCIPLINES_FIFO:
case CORE_MUTEX_DISCIPLINES_PRIORITY:
the_mutex_attributes.only_owner_release = FALSE;
break;
case CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING:
case CORE_MUTEX_DISCIPLINES_PRIORITY_INHERIT:
the_mutex_attributes.only_owner_release = TRUE;
break;
}
} else {
the_mutex_attributes.lock_nesting_behavior = CORE_MUTEX_NESTING_BLOCKS;
the_mutex_attributes.only_owner_release = FALSE;
}
the_mutex_attributes.priority_ceiling = priority_ceiling;
if ( count == 1 )
lock = CORE_MUTEX_UNLOCKED;
else
lock = CORE_MUTEX_LOCKED;
_CORE_mutex_Initialize(
&the_semaphore->Core_control.mutex,
OBJECTS_RTEMS_SEMAPHORES,
&the_mutex_attributes,
lock,
#if defined(RTEMS_MULTIPROCESSING)
_Semaphore_MP_Send_extract_proxy
#else
NULL
#endif
);
} else {
if ( _Attributes_Is_priority( attribute_set ) )
the_semaphore_attributes.discipline = CORE_SEMAPHORE_DISCIPLINES_PRIORITY;
else
the_semaphore_attributes.discipline = CORE_SEMAPHORE_DISCIPLINES_FIFO;
/*
* This effectively disables limit checking.
*/
the_semaphore_attributes.maximum_count = 0xFFFFFFFF;
/*
* The following are just to make Purify happy.
*/
the_mutex_attributes.lock_nesting_behavior = CORE_MUTEX_NESTING_ACQUIRES;
the_mutex_attributes.priority_ceiling = PRIORITY_MINIMUM;
_CORE_semaphore_Initialize(
&the_semaphore->Core_control.semaphore,
OBJECTS_RTEMS_SEMAPHORES,
&the_semaphore_attributes,
count,
#if defined(RTEMS_MULTIPROCESSING)
_Semaphore_MP_Send_extract_proxy
#else
NULL
#endif
);
}
_Objects_Open( &_Semaphore_Information, &the_semaphore->Object, &name );
*id = the_semaphore->Object.id;
#if defined(RTEMS_MULTIPROCESSING)
if ( _Attributes_Is_global( attribute_set ) )
_Semaphore_MP_Send_process_packet(
SEMAPHORE_MP_ANNOUNCE_CREATE,
the_semaphore->Object.id,
name,
0 /* Not used */
);
#endif
_Thread_Enable_dispatch();
return RTEMS_SUCCESSFUL;
}
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