/**
* @file
*
* @brief rtems_semaphore_create
* @ingroup ClassicSem Semaphores
*/
/*
* COPYRIGHT (c) 1989-2014.
* 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.rtems.com/license/LICENSE.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/system.h>
#include <rtems/rtems/status.h>
#include <rtems/rtems/support.h>
#include <rtems/rtems/attrimpl.h>
#include <rtems/score/isr.h>
#include <rtems/rtems/options.h>
#include <rtems/rtems/semimpl.h>
#include <rtems/rtems/tasksimpl.h>
#include <rtems/score/coremuteximpl.h>
#include <rtems/score/coresemimpl.h>
#include <rtems/score/threaddispatch.h>
#include <rtems/score/sysstate.h>
#include <rtems/score/interr.h>
/*
* 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,
uint32_t count,
rtems_attribute attribute_set,
rtems_task_priority priority_ceiling,
rtems_id *id
)
{
Semaphore_Control *the_semaphore;
CORE_mutex_Attributes the_mutex_attr;
CORE_semaphore_Attributes the_semaphore_attr;
CORE_mutex_Status mutex_status;
if ( !rtems_is_name_valid( name ) )
return RTEMS_INVALID_NAME;
if ( !id )
return RTEMS_INVALID_ADDRESS;
#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 ) ||
_Attributes_Is_priority_ceiling( 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_priority( attribute_set ) ) )
return RTEMS_NOT_DEFINED;
}
if ( _Attributes_Is_inherit_priority( attribute_set ) &&
_Attributes_Is_priority_ceiling( 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;
/*
* Initialize it as a counting semaphore.
*/
if ( _Attributes_Is_counting_semaphore( attribute_set ) ) {
/*
* This effectively disables limit checking.
*/
the_semaphore_attr.maximum_count = 0xFFFFFFFF;
if ( _Attributes_Is_priority( attribute_set ) )
the_semaphore_attr.discipline = CORE_SEMAPHORE_DISCIPLINES_PRIORITY;
else
the_semaphore_attr.discipline = CORE_SEMAPHORE_DISCIPLINES_FIFO;
/*
* The following are just to make Purify happy.
*/
the_mutex_attr.lock_nesting_behavior = CORE_MUTEX_NESTING_ACQUIRES;
the_mutex_attr.priority_ceiling = PRIORITY_MINIMUM;
_CORE_semaphore_Initialize(
&the_semaphore->Core_control.semaphore,
&the_semaphore_attr,
count
);
} else {
/*
* It is either simple binary semaphore or a more powerful mutex
* style binary semaphore. This is the mutex style.
*/
if ( _Attributes_Is_priority( attribute_set ) )
the_mutex_attr.discipline = CORE_MUTEX_DISCIPLINES_PRIORITY;
else
the_mutex_attr.discipline = CORE_MUTEX_DISCIPLINES_FIFO;
if ( _Attributes_Is_binary_semaphore( attribute_set ) ) {
the_mutex_attr.priority_ceiling = _RTEMS_tasks_Priority_to_Core(
priority_ceiling
);
the_mutex_attr.lock_nesting_behavior = CORE_MUTEX_NESTING_ACQUIRES;
the_mutex_attr.only_owner_release = false;
if ( the_mutex_attr.discipline == CORE_MUTEX_DISCIPLINES_PRIORITY ) {
if ( _Attributes_Is_inherit_priority( attribute_set ) ) {
the_mutex_attr.discipline = CORE_MUTEX_DISCIPLINES_PRIORITY_INHERIT;
the_mutex_attr.only_owner_release = true;
} else if ( _Attributes_Is_priority_ceiling( attribute_set ) ) {
the_mutex_attr.discipline = CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING;
the_mutex_attr.only_owner_release = true;
}
}
} else /* must be simple binary semaphore */ {
the_mutex_attr.lock_nesting_behavior = CORE_MUTEX_NESTING_BLOCKS;
the_mutex_attr.only_owner_release = false;
}
mutex_status = _CORE_mutex_Initialize(
&the_semaphore->Core_control.mutex,
_Thread_Executing,
&the_mutex_attr,
(count == 1) ? CORE_MUTEX_UNLOCKED : CORE_MUTEX_LOCKED
);
if ( mutex_status == CORE_MUTEX_STATUS_CEILING_VIOLATED ) {
_Semaphore_Free( the_semaphore );
_Thread_Enable_dispatch();
return RTEMS_INVALID_PRIORITY;
}
}
/*
* Whether we initialized it as a mutex or counting semaphore, it is
* now ready to be "offered" for use as a Classic API Semaphore.
*/
_Objects_Open(
&_Semaphore_Information,
&the_semaphore->Object,
(Objects_Name) 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;
}
