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Diffstat (limited to 'libpthread/linuxthreads/mutex.c')
-rw-r--r--libpthread/linuxthreads/mutex.c216
1 files changed, 176 insertions, 40 deletions
diff --git a/libpthread/linuxthreads/mutex.c b/libpthread/linuxthreads/mutex.c
index 2ab9e7e55..3c97ea7d6 100644
--- a/libpthread/linuxthreads/mutex.c
+++ b/libpthread/linuxthreads/mutex.c
@@ -12,41 +12,51 @@
/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */
/* GNU Library General Public License for more details. */
-/* changes for uClibc: remove strong_alias'es and define the real symbol */
-
/* Mutexes */
-#include <features.h>
-#define __USE_GNU
+#include <bits/libc-lock.h>
#include <errno.h>
#include <sched.h>
#include <stddef.h>
+#include <limits.h>
#include "pthread.h"
#include "internals.h"
#include "spinlock.h"
#include "queue.h"
#include "restart.h"
-int pthread_mutex_init(pthread_mutex_t * mutex,
+int __pthread_mutex_init(pthread_mutex_t * mutex,
const pthread_mutexattr_t * mutex_attr)
{
__pthread_init_lock(&mutex->__m_lock);
mutex->__m_kind =
- mutex_attr == NULL ? PTHREAD_MUTEX_ADAPTIVE_NP : mutex_attr->__mutexkind;
+ mutex_attr == NULL ? PTHREAD_MUTEX_TIMED_NP : mutex_attr->__mutexkind;
mutex->__m_count = 0;
mutex->__m_owner = NULL;
return 0;
}
-//strong_alias (__pthread_mutex_init, pthread_mutex_init)
+strong_alias (__pthread_mutex_init, pthread_mutex_init)
-int pthread_mutex_destroy(pthread_mutex_t * mutex)
+int __pthread_mutex_destroy(pthread_mutex_t * mutex)
{
- if (mutex->__m_lock.__status != 0) return EBUSY;
- return 0;
+ switch (mutex->__m_kind) {
+ case PTHREAD_MUTEX_ADAPTIVE_NP:
+ case PTHREAD_MUTEX_RECURSIVE_NP:
+ if ((mutex->__m_lock.__status & 1) != 0)
+ return EBUSY;
+ return 0;
+ case PTHREAD_MUTEX_ERRORCHECK_NP:
+ case PTHREAD_MUTEX_TIMED_NP:
+ if (mutex->__m_lock.__status != 0)
+ return EBUSY;
+ return 0;
+ default:
+ return EINVAL;
+ }
}
-//strong_alias (__pthread_mutex_destroy, pthread_mutex_destroy)
+strong_alias (__pthread_mutex_destroy, pthread_mutex_destroy)
-int pthread_mutex_trylock(pthread_mutex_t * mutex)
+int __pthread_mutex_trylock(pthread_mutex_t * mutex)
{
pthread_descr self;
int retcode;
@@ -68,18 +78,21 @@ int pthread_mutex_trylock(pthread_mutex_t * mutex)
}
return retcode;
case PTHREAD_MUTEX_ERRORCHECK_NP:
- retcode = __pthread_trylock(&mutex->__m_lock);
+ retcode = __pthread_alt_trylock(&mutex->__m_lock);
if (retcode == 0) {
mutex->__m_owner = thread_self();
}
return retcode;
+ case PTHREAD_MUTEX_TIMED_NP:
+ retcode = __pthread_alt_trylock(&mutex->__m_lock);
+ return retcode;
default:
return EINVAL;
}
}
-//strong_alias (__pthread_mutex_trylock, pthread_mutex_trylock)
+strong_alias (__pthread_mutex_trylock, pthread_mutex_trylock)
-int pthread_mutex_lock(pthread_mutex_t * mutex)
+int __pthread_mutex_lock(pthread_mutex_t * mutex)
{
pthread_descr self;
@@ -100,22 +113,71 @@ int pthread_mutex_lock(pthread_mutex_t * mutex)
case PTHREAD_MUTEX_ERRORCHECK_NP:
self = thread_self();
if (mutex->__m_owner == self) return EDEADLK;
+ __pthread_alt_lock(&mutex->__m_lock, self);
+ mutex->__m_owner = self;
+ return 0;
+ case PTHREAD_MUTEX_TIMED_NP:
+ __pthread_alt_lock(&mutex->__m_lock, NULL);
+ return 0;
+ default:
+ return EINVAL;
+ }
+}
+strong_alias (__pthread_mutex_lock, pthread_mutex_lock)
+
+int __pthread_mutex_timedlock (pthread_mutex_t *mutex,
+ const struct timespec *abstime)
+{
+ pthread_descr self;
+ int res;
+
+ if (__builtin_expect (abstime->tv_nsec, 0) < 0
+ || __builtin_expect (abstime->tv_nsec, 0) >= 1000000000)
+ return EINVAL;
+
+ switch(mutex->__m_kind) {
+ case PTHREAD_MUTEX_ADAPTIVE_NP:
+ __pthread_lock(&mutex->__m_lock, NULL);
+ return 0;
+ case PTHREAD_MUTEX_RECURSIVE_NP:
+ self = thread_self();
+ if (mutex->__m_owner == self) {
+ mutex->__m_count++;
+ return 0;
+ }
__pthread_lock(&mutex->__m_lock, self);
mutex->__m_owner = self;
+ mutex->__m_count = 0;
return 0;
+ case PTHREAD_MUTEX_ERRORCHECK_NP:
+ self = thread_self();
+ if (mutex->__m_owner == self) return EDEADLK;
+ res = __pthread_alt_timedlock(&mutex->__m_lock, self, abstime);
+ if (res != 0)
+ {
+ mutex->__m_owner = self;
+ return 0;
+ }
+ return ETIMEDOUT;
+ case PTHREAD_MUTEX_TIMED_NP:
+ /* Only this type supports timed out lock. */
+ return (__pthread_alt_timedlock(&mutex->__m_lock, NULL, abstime)
+ ? 0 : ETIMEDOUT);
default:
return EINVAL;
}
}
-//strong_alias (__pthread_mutex_lock, pthread_mutex_lock)
+strong_alias (__pthread_mutex_timedlock, pthread_mutex_timedlock)
-int pthread_mutex_unlock(pthread_mutex_t * mutex)
+int __pthread_mutex_unlock(pthread_mutex_t * mutex)
{
switch (mutex->__m_kind) {
case PTHREAD_MUTEX_ADAPTIVE_NP:
__pthread_unlock(&mutex->__m_lock);
return 0;
case PTHREAD_MUTEX_RECURSIVE_NP:
+ if (mutex->__m_owner != thread_self())
+ return EPERM;
if (mutex->__m_count > 0) {
mutex->__m_count--;
return 0;
@@ -127,38 +189,42 @@ int pthread_mutex_unlock(pthread_mutex_t * mutex)
if (mutex->__m_owner != thread_self() || mutex->__m_lock.__status == 0)
return EPERM;
mutex->__m_owner = NULL;
- __pthread_unlock(&mutex->__m_lock);
+ __pthread_alt_unlock(&mutex->__m_lock);
+ return 0;
+ case PTHREAD_MUTEX_TIMED_NP:
+ __pthread_alt_unlock(&mutex->__m_lock);
return 0;
default:
return EINVAL;
}
}
-//strong_alias (__pthread_mutex_unlock, pthread_mutex_unlock)
+strong_alias (__pthread_mutex_unlock, pthread_mutex_unlock)
-int pthread_mutexattr_init(pthread_mutexattr_t *attr)
+int __pthread_mutexattr_init(pthread_mutexattr_t *attr)
{
- attr->__mutexkind = PTHREAD_MUTEX_ADAPTIVE_NP;
+ attr->__mutexkind = PTHREAD_MUTEX_TIMED_NP;
return 0;
}
-//strong_alias (__pthread_mutexattr_init, pthread_mutexattr_init)
+strong_alias (__pthread_mutexattr_init, pthread_mutexattr_init)
-int pthread_mutexattr_destroy(pthread_mutexattr_t *attr)
+int __pthread_mutexattr_destroy(pthread_mutexattr_t *attr)
{
return 0;
}
-//strong_alias (__pthread_mutexattr_destroy, pthread_mutexattr_destroy)
+strong_alias (__pthread_mutexattr_destroy, pthread_mutexattr_destroy)
int __pthread_mutexattr_settype(pthread_mutexattr_t *attr, int kind)
{
if (kind != PTHREAD_MUTEX_ADAPTIVE_NP
&& kind != PTHREAD_MUTEX_RECURSIVE_NP
- && kind != PTHREAD_MUTEX_ERRORCHECK_NP)
+ && kind != PTHREAD_MUTEX_ERRORCHECK_NP
+ && kind != PTHREAD_MUTEX_TIMED_NP)
return EINVAL;
attr->__mutexkind = kind;
return 0;
}
weak_alias (__pthread_mutexattr_settype, pthread_mutexattr_settype)
-weak_alias ( __pthread_mutexattr_settype, __pthread_mutexattr_setkind_np)
+strong_alias ( __pthread_mutexattr_settype, __pthread_mutexattr_setkind_np)
weak_alias (__pthread_mutexattr_setkind_np, pthread_mutexattr_setkind_np)
int __pthread_mutexattr_gettype(const pthread_mutexattr_t *attr, int *kind)
@@ -167,24 +233,27 @@ int __pthread_mutexattr_gettype(const pthread_mutexattr_t *attr, int *kind)
return 0;
}
weak_alias (__pthread_mutexattr_gettype, pthread_mutexattr_gettype)
-weak_alias (__pthread_mutexattr_gettype, __pthread_mutexattr_getkind_np)
+strong_alias (__pthread_mutexattr_gettype, __pthread_mutexattr_getkind_np)
weak_alias (__pthread_mutexattr_getkind_np, pthread_mutexattr_getkind_np)
-int __pthread_mutexattr_getpshared (const pthread_mutexattr_t *attr, int *pshared)
+int __pthread_mutexattr_getpshared (const pthread_mutexattr_t *attr,
+ int *pshared)
{
- *pshared = PTHREAD_PROCESS_PRIVATE;
- return 0;
+ *pshared = PTHREAD_PROCESS_PRIVATE;
+ return 0;
}
weak_alias (__pthread_mutexattr_getpshared, pthread_mutexattr_getpshared)
int __pthread_mutexattr_setpshared (pthread_mutexattr_t *attr, int pshared)
{
- if (pshared != PTHREAD_PROCESS_PRIVATE && pshared != PTHREAD_PROCESS_SHARED)
- return EINVAL;
- /* For now it is not possible to shared a conditional variable. */
- if (pshared != PTHREAD_PROCESS_PRIVATE)
- return ENOSYS;
- return 0;
+ if (pshared != PTHREAD_PROCESS_PRIVATE && pshared != PTHREAD_PROCESS_SHARED)
+ return EINVAL;
+
+ /* For now it is not possible to shared a conditional variable. */
+ if (pshared != PTHREAD_PROCESS_PRIVATE)
+ return ENOSYS;
+
+ return 0;
}
weak_alias (__pthread_mutexattr_setpshared, pthread_mutexattr_setpshared)
@@ -192,30 +261,97 @@ weak_alias (__pthread_mutexattr_setpshared, pthread_mutexattr_setpshared)
static pthread_mutex_t once_masterlock = PTHREAD_MUTEX_INITIALIZER;
static pthread_cond_t once_finished = PTHREAD_COND_INITIALIZER;
+static int fork_generation = 0; /* Child process increments this after fork. */
enum { NEVER = 0, IN_PROGRESS = 1, DONE = 2 };
+/* If a thread is canceled while calling the init_routine out of
+ pthread once, this handler will reset the once_control variable
+ to the NEVER state. */
+
+static void pthread_once_cancelhandler(void *arg)
+{
+ pthread_once_t *once_control = arg;
+
+ pthread_mutex_lock(&once_masterlock);
+ *once_control = NEVER;
+ pthread_mutex_unlock(&once_masterlock);
+ pthread_cond_broadcast(&once_finished);
+}
+
int __pthread_once(pthread_once_t * once_control, void (*init_routine)(void))
{
+ /* flag for doing the condition broadcast outside of mutex */
+ int state_changed;
+
/* Test without locking first for speed */
- if (*once_control == DONE) return 0;
+ if (*once_control == DONE) {
+ READ_MEMORY_BARRIER();
+ return 0;
+ }
/* Lock and test again */
+
+ state_changed = 0;
+
pthread_mutex_lock(&once_masterlock);
+
+ /* If this object was left in an IN_PROGRESS state in a parent
+ process (indicated by stale generation field), reset it to NEVER. */
+ if ((*once_control & 3) == IN_PROGRESS && (*once_control & ~3) != fork_generation)
+ *once_control = NEVER;
+
/* If init_routine is being called from another routine, wait until
it completes. */
- while (*once_control == IN_PROGRESS) {
+ while ((*once_control & 3) == IN_PROGRESS) {
pthread_cond_wait(&once_finished, &once_masterlock);
}
/* Here *once_control is stable and either NEVER or DONE. */
if (*once_control == NEVER) {
- *once_control = IN_PROGRESS;
+ *once_control = IN_PROGRESS | fork_generation;
pthread_mutex_unlock(&once_masterlock);
+ pthread_cleanup_push(pthread_once_cancelhandler, once_control);
init_routine();
+ pthread_cleanup_pop(0);
pthread_mutex_lock(&once_masterlock);
+ WRITE_MEMORY_BARRIER();
*once_control = DONE;
- pthread_cond_broadcast(&once_finished);
+ state_changed = 1;
}
pthread_mutex_unlock(&once_masterlock);
+
+ if (state_changed)
+ pthread_cond_broadcast(&once_finished);
+
return 0;
}
strong_alias (__pthread_once, pthread_once)
+
+/*
+ * Handle the state of the pthread_once mechanism across forks. The
+ * once_masterlock is acquired in the parent process prior to a fork to ensure
+ * that no thread is in the critical region protected by the lock. After the
+ * fork, the lock is released. In the child, the lock and the condition
+ * variable are simply reset. The child also increments its generation
+ * counter which lets pthread_once calls detect stale IN_PROGRESS states
+ * and reset them back to NEVER.
+ */
+
+void __pthread_once_fork_prepare(void)
+{
+ pthread_mutex_lock(&once_masterlock);
+}
+
+void __pthread_once_fork_parent(void)
+{
+ pthread_mutex_unlock(&once_masterlock);
+}
+
+void __pthread_once_fork_child(void)
+{
+ pthread_mutex_init(&once_masterlock, NULL);
+ pthread_cond_init(&once_finished, NULL);
+ if (fork_generation <= INT_MAX - 4)
+ fork_generation += 4; /* leave least significant two bits zero */
+ else
+ fork_generation = 0;
+}