diff options
Diffstat (limited to 'cpukit/posix/src/semtimedwait.c')
-rw-r--r-- | cpukit/posix/src/semtimedwait.c | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/cpukit/posix/src/semtimedwait.c b/cpukit/posix/src/semtimedwait.c new file mode 100644 index 0000000000..60faafc242 --- /dev/null +++ b/cpukit/posix/src/semtimedwait.c @@ -0,0 +1,81 @@ +/* + * 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 <stdarg.h> + +#include <errno.h> +#include <fcntl.h> +#include <pthread.h> +#include <semaphore.h> +#include <limits.h> + +#include <rtems/system.h> +#include <rtems/score/object.h> +#include <rtems/posix/semaphore.h> +#include <rtems/posix/time.h> +#include <rtems/seterr.h> + +/*PAGE + * + * 11.2.6 Lock a Semaphore, P1003.1b-1993, p.226 + * + * NOTE: P1003.4b/D8 adds sem_timedwait(), p. 27 + */ + +int sem_timedwait( + sem_t *sem, + 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_Semaphore_Wait_support( sem, do_wait, ticks ); + + /* + * This service only gives us the option to block. We used a polling + * attempt to obtain if the abstime was not in the future. If we did + * not obtain the semaphore, then not look at the status immediately, + * make sure the right reason is returned. + */ + if ( !do_wait && (lock_status == EBUSY) ) { + if ( lock_status == POSIX_ABSOLUTE_TIMEOUT_INVALID ) + rtems_set_errno_and_return_minus_one( EINVAL ); + if ( lock_status == POSIX_ABSOLUTE_TIMEOUT_IS_IN_PAST || + lock_status == POSIX_ABSOLUTE_TIMEOUT_IS_NOW ) + rtems_set_errno_and_return_minus_one( ETIMEDOUT ); + } + + return lock_status; +} |