diff options
Diffstat (limited to 'sysdeps/htl/pt-mutex-timedlock.c')
| -rw-r--r-- | sysdeps/htl/pt-mutex-timedlock.c | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/sysdeps/htl/pt-mutex-timedlock.c b/sysdeps/htl/pt-mutex-timedlock.c new file mode 100644 index 0000000000..942ccc9b75 --- /dev/null +++ b/sysdeps/htl/pt-mutex-timedlock.c @@ -0,0 +1,195 @@ +/* Lock a mutex with a timeout. Generic version. + Copyright (C) 2000-2018 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <pthread.h> +#include <assert.h> + +#include <pt-internal.h> + +#define LOSE do { * (int *) 0 = 0; } while (1) + +/* Try to lock MUTEX, block until *ABSTIME if it is already held. As + a GNU extension, if TIMESPEC is NULL then wait forever. */ +int +__pthread_mutex_timedlock_internal (struct __pthread_mutex *mutex, + const struct timespec *abstime) +{ + error_t err; + int drain; + struct __pthread *self; + const struct __pthread_mutexattr *attr = mutex->__attr; + + if (attr == __PTHREAD_ERRORCHECK_MUTEXATTR) + attr = &__pthread_errorcheck_mutexattr; + if (attr == __PTHREAD_RECURSIVE_MUTEXATTR) + attr = &__pthread_recursive_mutexattr; + + __pthread_spin_lock (&mutex->__lock); + if (__pthread_spin_trylock (&mutex->__held) == 0) + /* Successfully acquired the lock. */ + { +#ifdef ALWAYS_TRACK_MUTEX_OWNER +# ifndef NDEBUG + self = _pthread_self (); + if (self != NULL) + /* The main thread may take a lock before the library is fully + initialized, in particular, before the main thread has a + TCB. */ + { + assert (mutex->__owner == NULL); + mutex->__owner = _pthread_self (); + } +# endif +#endif + + if (attr != NULL) + switch (attr->__mutex_type) + { + case PTHREAD_MUTEX_NORMAL: + break; + + case PTHREAD_MUTEX_RECURSIVE: + mutex->__locks = 1; + case PTHREAD_MUTEX_ERRORCHECK: + mutex->__owner = _pthread_self (); + break; + + default: + LOSE; + } + + __pthread_spin_unlock (&mutex->__lock); + return 0; + } + + /* The lock is busy. */ + + self = _pthread_self (); + assert (self); + + if (attr == NULL || attr->__mutex_type == PTHREAD_MUTEX_NORMAL) + { +#if defined(ALWAYS_TRACK_MUTEX_OWNER) + assert (mutex->__owner != self); +#endif + } + else + { + switch (attr->__mutex_type) + { + case PTHREAD_MUTEX_ERRORCHECK: + if (mutex->__owner == self) + { + __pthread_spin_unlock (&mutex->__lock); + return EDEADLK; + } + break; + + case PTHREAD_MUTEX_RECURSIVE: + if (mutex->__owner == self) + { + mutex->__locks++; + __pthread_spin_unlock (&mutex->__lock); + return 0; + } + break; + + default: + LOSE; + } + } + +#if !defined(ALWAYS_TRACK_MUTEX_OWNER) + if (attr != NULL && attr->__mutex_type != PTHREAD_MUTEX_NORMAL) +#endif + assert (mutex->__owner); + + if (abstime != NULL && (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)) + return EINVAL; + + /* Add ourselves to the queue. */ + __pthread_enqueue (&mutex->__queue, self); + __pthread_spin_unlock (&mutex->__lock); + + /* Block the thread. */ + if (abstime != NULL) + err = __pthread_timedblock (self, abstime, CLOCK_REALTIME); + else + { + err = 0; + __pthread_block (self); + } + + __pthread_spin_lock (&mutex->__lock); + if (self->prevp == NULL) + /* Another thread removed us from the queue, which means a wakeup message + has been sent. It was either consumed while we were blocking, or + queued after we timed out and before we acquired the mutex lock, in + which case the message queue must be drained. */ + drain = err ? 1 : 0; + else + { + /* We're still in the queue. Noone attempted to wake us up, i.e. we + timed out. */ + __pthread_dequeue (self); + drain = 0; + } + __pthread_spin_unlock (&mutex->__lock); + + if (drain) + __pthread_block (self); + + if (err) + { + assert (err == ETIMEDOUT); + return err; + } + +#if !defined(ALWAYS_TRACK_MUTEX_OWNER) + if (attr != NULL && attr->__mutex_type != PTHREAD_MUTEX_NORMAL) +#endif + { + assert (mutex->__owner == self); + } + + if (attr != NULL) + switch (attr->__mutex_type) + { + case PTHREAD_MUTEX_NORMAL: + break; + + case PTHREAD_MUTEX_RECURSIVE: + assert (mutex->__locks == 0); + mutex->__locks = 1; + case PTHREAD_MUTEX_ERRORCHECK: + mutex->__owner = self; + break; + + default: + LOSE; + } + + return 0; +} + +int +pthread_mutex_timedlock (struct __pthread_mutex *mutex, + const struct timespec *abstime) +{ + return __pthread_mutex_timedlock_internal (mutex, abstime); +} |