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9 commits

Author SHA1 Message Date
Tom Cherry
c6b5bcd182 Add _monotonic_np versions of timed wait functions
As a follow up to Ibba98f5d88be1c306d14e9b9366302ecbef6d534, where we
added a work around to convert the CLOCK_REALTIME timeouts to
CLOCK_MONOTONIC for pthread and semaphore timed wait functions, we're
introducing a set of _monotonic_np versions of each of these functions
that wait on CLOCK_MONOTONIC directly.

The primary motivation here is that while the above work around helps
for 3rd party code, it creates a dilemma when implementing new code
that would use these functions: either one implements code with these
functions knowing there is a race condition possible or one avoids
these functions and reinvent their own waiting/signaling mechanisms.
Neither are satisfactory, so we create a third option to use these
Android specific _monotonic_np functions that completely remove the
race condition while keeping the rest of the interface.

Specifically this adds the below functions:
pthread_mutex_timedlock_monotonic_np()
pthread_cond_timedwait_monotonic_np()
pthread_rwlock_timedrdlock_monotonic_np()
pthread_rwlock_timedwrlock_monotonic_np()
sem_timedwait_monotonic_np()

Note that pthread_cond_timedwait_monotonic_np() previously existed and
was removed since it's possible to initialize a condition variable to
use CLOCK_MONOTONIC.  It is added back for a mix of reasons,
1) Symmetry with the rest of the functions we're adding
2) libc++ cannot easily take advantage of the new initializer, but
   will be able to use this function in order to wait on
   std::steady_clock
3) Frankly, it's a better API to specify the clock in the waiter function
   than to specify the clock when the condition variable is
   initialized.

Bug: 73951740
Test: new unit tests
Change-Id: I23aa5c204e36a194237d41e064c5c8ccaa4204e3
2018-03-20 18:41:22 -07:00
Elliott Hughes
71ba5899ae Rewrite system(3) to use posix_spawn(3).
We saw crashes from pthread_exit+debuggerd on LP32
(https://issuetracker.google.com/72291624), and it seems like the
equivalent problem should exist with system(3). I fixed posix_spawn(3)
as part of that bug, so the easiest fix is probably to reuse that.

Bug: http://b/72470344
Test: ran tests
Change-Id: I05f838706f2b4a14ac3ee21292833e6c8579b0d4
2018-03-05 17:20:12 -08:00
Elliott Hughes
5bc78c8bcd Add and use constants for the Android API levels.
Test: bionic tests still pass
Change-Id: If1b619cfc9db1d3f5d91f14f2ace71058dca0c4a
2016-11-16 16:55:42 -08:00
Yabin Cui
ca48274298 Revert "Revert "Make sem_wait able to return errno EINTR for sdk > 23.""
This reverts commit 6d51085202.
And add missing bionic_sdk_version.h.

Change-Id: I24cc738b1fd1d26234c52afbc787f5b3c4a9c9cb
2016-01-25 17:39:18 -08:00
Dan Albert
6d51085202 Revert "Make sem_wait able to return errno EINTR for sdk > 23."
Broke the build. There's no such file as bionic_sdk_version.h anywhere in the tree.

This reverts commit 892b61d340.

Change-Id: Iec3f4588edfb1d1524bb5f16451fd05dc6ebe44a
2016-01-26 00:20:06 +00:00
Yabin Cui
892b61d340 Make sem_wait able to return errno EINTR for sdk > 23.
Posix standards says sem_wait is interruptible by the delivery
of a signal. To keep compatiblity with old apps, only fix that
in newer sdk versions.

Bug: 26743454

Change-Id: I924cbb436658e3e0f397c922d866ece99b8241a3
2016-01-25 13:44:39 -08:00
Elliott Hughes
dd586f2ebd sem_timedwait with a null timeout doesn't mean "forever".
It actually means "crash immediately". Well, it's an error. And callers are
much more likely to realize their mistake if we crash immediately rather
than return EINVAL. Historically, glibc has crashed and bionic -- before
the recent changes -- returned EINVAL, so this is a behavior change.

Change-Id: I0c2373a6703b20b8a97aacc1e66368a5885e8c51
2015-12-16 15:15:58 -08:00
Yabin Cui
c9a659c57b Use FUTEX_WAIT_BITSET to avoid converting timeouts.
Add unittests for pthread APIs with timeout parameter.

Bug: 17569991

Change-Id: I6b3b9b2feae03680654cd64c3112ce7644632c87
2015-11-19 13:42:03 -08:00
Elliott Hughes
04303f5a8a Add semaphore tests, fix sem_destroy.
Bug: https://code.google.com/p/android/issues/detail?id=76088
Change-Id: I4a0561b23e90312384d40a1c804ca64ee98f4066
2014-09-19 17:37:06 -07:00