path: root/cpukit/posix/src/mutexsetprioceiling.c

/**
 * @file
 *
 * @brief Changes the Priority Ceiling of a Mutex and Releases it
 * @ingroup POSIXAPI
 */

/*
 *  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.
 */

#if HAVE_CONFIG_H
#include "config.h"
#endif

#include <errno.h>
#include <pthread.h>

#include <rtems/system.h>
#include <rtems/score/coremuteximpl.h>
#include <rtems/score/watchdog.h>
#include <rtems/posix/muteximpl.h>
#include <rtems/posix/priorityimpl.h>

/*
 *  13.6.2 Change the Priority Ceiling of a Mutex, P1003.1c/Draft 10, p. 131
 */

int pthread_mutex_setprioceiling(
  pthread_mutex_t   *mutex,
  int                prioceiling,
  int               *old_ceiling
)
{
  register POSIX_Mutex_Control *the_mutex;
  Objects_Locations             location;
  Priority_Control              the_priority;
  ISR_lock_Context              lock_context;

  if ( !old_ceiling )
    return EINVAL;

  if ( !_POSIX_Priority_Is_valid( prioceiling ) )
    return EINVAL;

  the_priority = _POSIX_Priority_To_core( prioceiling );

  /*
   *  Must acquire the mutex before we can change it's ceiling.
   *  POSIX says block until we acquire it.
   */
  (void) pthread_mutex_lock( mutex );

  /*
   *  Do not worry about the return code from this.  The Get operation
   *  will also fail if it is a bad id or was deleted between the two
   *  operations.
   *
   *  NOTE: This makes it easier to get 100% binary coverage since the
   *        bad Id case is handled by the switch.
   */
  the_mutex = _POSIX_Mutex_Get_interrupt_disable(
    mutex,
    &location,
    &lock_context
  );
  switch ( location ) {

    case OBJECTS_LOCAL:
      *old_ceiling = _POSIX_Priority_From_core(
        the_mutex->Mutex.Attributes.priority_ceiling
      );
      the_mutex->Mutex.Attributes.priority_ceiling = the_priority;
      /*
       *  We are required to unlock the mutex before we return.
       */
      _CORE_mutex_Surrender(
        &the_mutex->Mutex,
        NULL,
        0,
        &lock_context
      );

      return 0;

#if defined(RTEMS_MULTIPROCESSING)
    case OBJECTS_REMOTE:  /* impossible to get here */
#endif
    case OBJECTS_ERROR:
      break;
  }

  return EINVAL;
}