diff options
Diffstat (limited to 'cpukit/posix/src/mutextimedlock.c')
-rw-r--r-- | cpukit/posix/src/mutextimedlock.c | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/cpukit/posix/src/mutextimedlock.c b/cpukit/posix/src/mutextimedlock.c new file mode 100644 index 0000000000..7773d84af6 --- /dev/null +++ b/cpukit/posix/src/mutextimedlock.c @@ -0,0 +1,83 @@ +/* + * Mutex Timed Lock + */ + +/* + * COPYRIGHT (c) 1989-2008. + * 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. + * + * $Id$ + */ + +#if HAVE_CONFIG_H +#include "config.h" +#endif + +#include <errno.h> +#include <pthread.h> + +#include <rtems/system.h> +#include <rtems/score/coremutex.h> +#include <rtems/score/watchdog.h> +#if defined(RTEMS_MULTIPROCESSING) +#include <rtems/score/mpci.h> +#endif +#include <rtems/posix/mutex.h> +#include <rtems/posix/priority.h> +#include <rtems/posix/time.h> + +/*PAGE + * + * 11.3.3 Locking and Unlocking a Mutex, P1003.1c/Draft 10, p. 93 + * + * NOTE: P1003.4b/D8 adds pthread_mutex_timedlock(), p. 29 + */ + +int pthread_mutex_timedlock( + pthread_mutex_t *mutex, + const struct timespec *abstime +) +{ + Watchdog_Interval ticks; + bool do_wait = true; + POSIX_Absolute_timeout_conversion_results_t status; + int lock_status; + + /* + * POSIX requires that blocking calls with timeouts that take + * an absolute timeout must ignore issues with the absolute + * time provided if the operation would otherwise succeed. + * So we check the abstime provided, and hold on to whether it + * is valid or not. If it isn't correct and in the future, + * then we do a polling operation and convert the UNSATISFIED + * status into the appropriate error. + * + * If the status is POSIX_ABSOLUTE_TIMEOUT_INVALID, + * POSIX_ABSOLUTE_TIMEOUT_IS_IN_PAST, or POSIX_ABSOLUTE_TIMEOUT_IS_NOW, + * then we should not wait. + */ + status = _POSIX_Absolute_timeout_to_ticks( abstime, &ticks ); + if ( status != POSIX_ABSOLUTE_TIMEOUT_IS_IN_FUTURE ) + do_wait = false; + + lock_status = _POSIX_Mutex_Lock_support( mutex, do_wait, ticks ); + /* + * This service only gives us the option to block. We used a polling + * attempt to lock if the abstime was not in the future. If we did + * not obtain the mutex, then not look at the status immediately, + * make sure the right reason is returned. + */ + if ( !do_wait && (lock_status == EBUSY) ) { + if ( status == POSIX_ABSOLUTE_TIMEOUT_INVALID ) + return EINVAL; + if ( status == POSIX_ABSOLUTE_TIMEOUT_IS_IN_PAST || + status == POSIX_ABSOLUTE_TIMEOUT_IS_NOW ) + return ETIMEDOUT; + } + + return lock_status; +} |