POSIX Blocking Calls with Timeouts as Absolute Times

[Joel Sherrill]

This patch addresses issues on implementation of the timeout on the following POSIX services. Some of these services incorrectly took a timeout as a relative time. Others would compute a 0 delta to timeout if the absolute time and the current time were equal and thus incorrectly block the caller forever. The root of the confusion is that POSIX specifies that if the timeout is incorrect (e.g. in the past, is now, or is numerically invalid), that it does not matter if the call would succeed without blocking. This is in contrast to RTEMS programming style where all errors are checked before any critical sections are entered.

This fix implemented a more uniform way of handling POSIX absolute time timeouts.

pthread_cond_timedwait - could block forever
mq_timedreceive - used relative not absolute time
mq_timedsend - used relative not absolute time
pthread_mutex_timedlock - used relative not absolute time
pthread_rwlock_timedrdlock- used relative not absolute time
pthread_rwlock_timedwrlock- used relative not absolute time
sem_timedwait - could block forever

[Joel Sherrill]

Fix against CVS.

[Joel Sherrill]

version of patch for 4.8 branch.

[Joel Sherrill]

version of patch for 4.7 branch.

[Joel Sherrill]

Patch applied to all active branches and tested.