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/**
* @file
*
* @ingroup POSIXAPI
*
* @brief Initialize a Mutex
*/
/*
* COPYRIGHT (c) 1989-2009.
* 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.org/license/LICENSE.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/posix/muteximpl.h>
#include <rtems/posix/posixapi.h>
#include <rtems/posix/priorityimpl.h>
#include <rtems/score/schedulerimpl.h>
#include <limits.h>
RTEMS_STATIC_ASSERT(
offsetof( POSIX_Mutex_Control, flags )
== offsetof( pthread_mutex_t, _flags ),
POSIX_MUTEX_CONTROL_FLAGS
);
RTEMS_STATIC_ASSERT(
offsetof( POSIX_Mutex_Control, Recursive )
== offsetof( pthread_mutex_t, _Recursive ),
POSIX_MUTEX_CONTROL_RECURSIVE
);
RTEMS_STATIC_ASSERT(
offsetof( POSIX_Mutex_Control, Priority_ceiling )
== offsetof( pthread_mutex_t, _Priority_ceiling ),
POSIX_MUTEX_CONTROL_PRIORITY_CEILING
);
RTEMS_STATIC_ASSERT(
offsetof( POSIX_Mutex_Control, scheduler )
== offsetof( pthread_mutex_t, _scheduler ),
POSIX_MUTEX_CONTROL_SCHEDULER
);
RTEMS_STATIC_ASSERT(
sizeof( POSIX_Mutex_Control ) == sizeof( pthread_mutex_t ),
POSIX_MUTEX_CONTROL_SIZE
);
const pthread_mutexattr_t _POSIX_Mutex_Default_attributes = {
#if defined(_UNIX98_THREAD_MUTEX_ATTRIBUTES)
.type = PTHREAD_MUTEX_DEFAULT,
#endif
.is_initialized = true,
.process_shared = PTHREAD_PROCESS_PRIVATE,
.prio_ceiling = INT_MAX,
.protocol = PTHREAD_PRIO_NONE,
.recursive = false
};
/**
* 11.3.2 Initializing and Destroying a Mutex, P1003.1c/Draft 10, p. 87
*
* NOTE: XXX Could be optimized so all the attribute error checking
* is not performed when attr is NULL.
*/
int pthread_mutex_init(
pthread_mutex_t *mutex,
const pthread_mutexattr_t *attr
)
{
POSIX_Mutex_Control *the_mutex;
const pthread_mutexattr_t *the_attr;
POSIX_Mutex_Protocol protocol;
unsigned long flags;
Priority_Control priority;
const Scheduler_Control *scheduler;
if ( attr ) the_attr = attr;
else the_attr = &_POSIX_Mutex_Default_attributes;
/* Check for NULL mutex */
if ( !mutex )
return EINVAL;
/*
* The POSIX specification says:
*
* "Attempting to initialize an already initialized mutex results
* in undefined behavior."
*
* Trying to keep the caller from doing the create when *mutex
* is actually a valid ID causes grief. All it takes is the wrong
* value in an uninitialized variable to make this fail.
*
* Thus, we do not look at *mutex.
*/
if ( !the_attr->is_initialized )
return EINVAL;
if ( !_POSIX_Is_valid_pshared( the_attr->process_shared ) ) {
return EINVAL;
}
/*
* Determine the discipline of the mutex
*/
switch ( the_attr->protocol ) {
case PTHREAD_PRIO_NONE:
protocol = POSIX_MUTEX_NO_PROTOCOL;
break;
case PTHREAD_PRIO_INHERIT:
protocol = POSIX_MUTEX_PRIORITY_INHERIT;
break;
case PTHREAD_PRIO_PROTECT:
protocol = POSIX_MUTEX_PRIORITY_CEILING;
break;
default:
return EINVAL;
}
#if defined(_UNIX98_THREAD_MUTEX_ATTRIBUTES)
/*
* Validate the mutex type and set appropriate SuperCore mutex
* attributes.
*/
switch ( the_attr->type ) {
case PTHREAD_MUTEX_NORMAL:
case PTHREAD_MUTEX_RECURSIVE:
case PTHREAD_MUTEX_ERRORCHECK:
case PTHREAD_MUTEX_DEFAULT:
break;
default:
return EINVAL;
}
#endif
the_mutex = _POSIX_Mutex_Get( mutex );
flags = (uintptr_t) the_mutex ^ POSIX_MUTEX_MAGIC;
flags &= ~POSIX_MUTEX_FLAGS_MASK;
flags |= protocol;
if ( the_attr->type == PTHREAD_MUTEX_RECURSIVE ) {
flags |= POSIX_MUTEX_RECURSIVE;
}
the_mutex->flags = flags;
if ( protocol == POSIX_MUTEX_PRIORITY_CEILING ) {
int prio_ceiling;
bool valid;
scheduler = _Thread_Scheduler_get_home( _Thread_Get_executing() );
prio_ceiling = the_attr->prio_ceiling;
if ( prio_ceiling == INT_MAX ) {
prio_ceiling = _POSIX_Priority_Get_maximum( scheduler );
}
priority = _POSIX_Priority_To_core( scheduler, prio_ceiling, &valid );
if ( !valid ) {
return EINVAL;
}
} else {
priority = 0;
scheduler = NULL;
}
_Thread_queue_Queue_initialize(
&the_mutex->Recursive.Mutex.Queue.Queue,
NULL
);
the_mutex->Recursive.nest_level = 0;
_Priority_Node_initialize( &the_mutex->Priority_ceiling, priority );
the_mutex->scheduler = scheduler;
return 0;
}
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