diff options
Diffstat (limited to 'lib/glthread')
| -rw-r--r-- | lib/glthread/lock.c | 1058 | ||||
| -rw-r--r-- | lib/glthread/lock.h | 927 | ||||
| -rw-r--r-- | lib/glthread/threadlib.c | 74 |
3 files changed, 2059 insertions, 0 deletions
diff --git a/lib/glthread/lock.c b/lib/glthread/lock.c new file mode 100644 index 00000000..2f4de9f4 --- /dev/null +++ b/lib/glthread/lock.c @@ -0,0 +1,1058 @@ +/* Locking in multithreaded situations. + Copyright (C) 2005-2010 Free Software Foundation, Inc. + + This program 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, or (at your option) + any later version. + + This program 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 this program; if not, write to the Free Software Foundation, + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + +/* Written by Bruno Haible <bruno@clisp.org>, 2005. + Based on GCC's gthr-posix.h, gthr-posix95.h, gthr-solaris.h, + gthr-win32.h. */ + +#include <config.h> + +#include "glthread/lock.h" + +/* ========================================================================= */ + +#if USE_POSIX_THREADS + +/* -------------------------- gl_lock_t datatype -------------------------- */ + +/* ------------------------- gl_rwlock_t datatype ------------------------- */ + +# if HAVE_PTHREAD_RWLOCK + +# if !defined PTHREAD_RWLOCK_INITIALIZER + +int +glthread_rwlock_init_multithreaded (gl_rwlock_t *lock) +{ + int err; + + err = pthread_rwlock_init (&lock->rwlock, NULL); + if (err != 0) + return err; + lock->initialized = 1; + return 0; +} + +int +glthread_rwlock_rdlock_multithreaded (gl_rwlock_t *lock) +{ + if (!lock->initialized) + { + int err; + + err = pthread_mutex_lock (&lock->guard); + if (err != 0) + return err; + if (!lock->initialized) + { + err = glthread_rwlock_init_multithreaded (lock); + if (err != 0) + { + pthread_mutex_unlock (&lock->guard); + return err; + } + } + err = pthread_mutex_unlock (&lock->guard); + if (err != 0) + return err; + } + return pthread_rwlock_rdlock (&lock->rwlock); +} + +int +glthread_rwlock_wrlock_multithreaded (gl_rwlock_t *lock) +{ + if (!lock->initialized) + { + int err; + + err = pthread_mutex_lock (&lock->guard); + if (err != 0) + return err; + if (!lock->initialized) + { + err = glthread_rwlock_init_multithreaded (lock); + if (err != 0) + { + pthread_mutex_unlock (&lock->guard); + return err; + } + } + err = pthread_mutex_unlock (&lock->guard); + if (err != 0) + return err; + } + return pthread_rwlock_wrlock (&lock->rwlock); +} + +int +glthread_rwlock_unlock_multithreaded (gl_rwlock_t *lock) +{ + if (!lock->initialized) + return EINVAL; + return pthread_rwlock_unlock (&lock->rwlock); +} + +int +glthread_rwlock_destroy_multithreaded (gl_rwlock_t *lock) +{ + int err; + + if (!lock->initialized) + return EINVAL; + err = pthread_rwlock_destroy (&lock->rwlock); + if (err != 0) + return err; + lock->initialized = 0; + return 0; +} + +# endif + +# else + +int +glthread_rwlock_init_multithreaded (gl_rwlock_t *lock) +{ + int err; + + err = pthread_mutex_init (&lock->lock, NULL); + if (err != 0) + return err; + err = pthread_cond_init (&lock->waiting_readers, NULL); + if (err != 0) + return err; + err = pthread_cond_init (&lock->waiting_writers, NULL); + if (err != 0) + return err; + lock->waiting_writers_count = 0; + lock->runcount = 0; + return 0; +} + +int +glthread_rwlock_rdlock_multithreaded (gl_rwlock_t *lock) +{ + int err; + + err = pthread_mutex_lock (&lock->lock); + if (err != 0) + return err; + /* Test whether only readers are currently running, and whether the runcount + field will not overflow. */ + /* POSIX says: "It is implementation-defined whether the calling thread + acquires the lock when a writer does not hold the lock and there are + writers blocked on the lock." Let's say, no: give the writers a higher + priority. */ + while (!(lock->runcount + 1 > 0 && lock->waiting_writers_count == 0)) + { + /* This thread has to wait for a while. Enqueue it among the + waiting_readers. */ + err = pthread_cond_wait (&lock->waiting_readers, &lock->lock); + if (err != 0) + { + pthread_mutex_unlock (&lock->lock); + return err; + } + } + lock->runcount++; + return pthread_mutex_unlock (&lock->lock); +} + +int +glthread_rwlock_wrlock_multithreaded (gl_rwlock_t *lock) +{ + int err; + + err = pthread_mutex_lock (&lock->lock); + if (err != 0) + return err; + /* Test whether no readers or writers are currently running. */ + while (!(lock->runcount == 0)) + { + /* This thread has to wait for a while. Enqueue it among the + waiting_writers. */ + lock->waiting_writers_count++; + err = pthread_cond_wait (&lock->waiting_writers, &lock->lock); + if (err != 0) + { + lock->waiting_writers_count--; + pthread_mutex_unlock (&lock->lock); + return err; + } + lock->waiting_writers_count--; + } + lock->runcount--; /* runcount becomes -1 */ + return pthread_mutex_unlock (&lock->lock); +} + +int +glthread_rwlock_unlock_multithreaded (gl_rwlock_t *lock) +{ + int err; + + err = pthread_mutex_lock (&lock->lock); + if (err != 0) + return err; + if (lock->runcount < 0) + { + /* Drop a writer lock. */ + if (!(lock->runcount == -1)) + { + pthread_mutex_unlock (&lock->lock); + return EINVAL; + } + lock->runcount = 0; + } + else + { + /* Drop a reader lock. */ + if (!(lock->runcount > 0)) + { + pthread_mutex_unlock (&lock->lock); + return EINVAL; + } + lock->runcount--; + } + if (lock->runcount == 0) + { + /* POSIX recommends that "write locks shall take precedence over read + locks", to avoid "writer starvation". */ + if (lock->waiting_writers_count > 0) + { + /* Wake up one of the waiting writers. */ + err = pthread_cond_signal (&lock->waiting_writers); + if (err != 0) + { + pthread_mutex_unlock (&lock->lock); + return err; + } + } + else + { + /* Wake up all waiting readers. */ + err = pthread_cond_broadcast (&lock->waiting_readers); + if (err != 0) + { + pthread_mutex_unlock (&lock->lock); + return err; + } + } + } + return pthread_mutex_unlock (&lock->lock); +} + +int +glthread_rwlock_destroy_multithreaded (gl_rwlock_t *lock) +{ + int err; + + err = pthread_mutex_destroy (&lock->lock); + if (err != 0) + return err; + err = pthread_cond_destroy (&lock->waiting_readers); + if (err != 0) + return err; + err = pthread_cond_destroy (&lock->waiting_writers); + if (err != 0) + return err; + return 0; +} + +# endif + +/* --------------------- gl_recursive_lock_t datatype --------------------- */ + +# if HAVE_PTHREAD_MUTEX_RECURSIVE + +# if defined PTHREAD_RECURSIVE_MUTEX_INITIALIZER || defined PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP + +int +glthread_recursive_lock_init_multithreaded (gl_recursive_lock_t *lock) +{ + pthread_mutexattr_t attributes; + int err; + + err = pthread_mutexattr_init (&attributes); + if (err != 0) + return err; + err = pthread_mutexattr_settype (&attributes, PTHREAD_MUTEX_RECURSIVE); + if (err != 0) + { + pthread_mutexattr_destroy (&attributes); + return err; + } + err = pthread_mutex_init (lock, &attributes); + if (err != 0) + { + pthread_mutexattr_destroy (&attributes); + return err; + } + err = pthread_mutexattr_destroy (&attributes); + if (err != 0) + return err; + return 0; +} + +# else + +int +glthread_recursive_lock_init_multithreaded (gl_recursive_lock_t *lock) +{ + pthread_mutexattr_t attributes; + int err; + + err = pthread_mutexattr_init (&attributes); + if (err != 0) + return err; + err = pthread_mutexattr_settype (&attributes, PTHREAD_MUTEX_RECURSIVE); + if (err != 0) + { + pthread_mutexattr_destroy (&attributes); + return err; + } + err = pthread_mutex_init (&lock->recmutex, &attributes); + if (err != 0) + { + pthread_mutexattr_destroy (&attributes); + return err; + } + err = pthread_mutexattr_destroy (&attributes); + if (err != 0) + return err; + lock->initialized = 1; + return 0; +} + +int +glthread_recursive_lock_lock_multithreaded (gl_recursive_lock_t *lock) +{ + if (!lock->initialized) + { + int err; + + err = pthread_mutex_lock (&lock->guard); + if (err != 0) + return err; + if (!lock->initialized) + { + err = glthread_recursive_lock_init_multithreaded (lock); + if (err != 0) + { + pthread_mutex_unlock (&lock->guard); + return err; + } + } + err = pthread_mutex_unlock (&lock->guard); + if (err != 0) + return err; + } + return pthread_mutex_lock (&lock->recmutex); +} + +int +glthread_recursive_lock_unlock_multithreaded (gl_recursive_lock_t *lock) +{ + if (!lock->initialized) + return EINVAL; + return pthread_mutex_unlock (&lock->recmutex); +} + +int +glthread_recursive_lock_destroy_multithreaded (gl_recursive_lock_t *lock) +{ + int err; + + if (!lock->initialized) + return EINVAL; + err = pthread_mutex_destroy (&lock->recmutex); + if (err != 0) + return err; + lock->initialized = 0; + return 0; +} + +# endif + +# else + +int +glthread_recursive_lock_init_multithreaded (gl_recursive_lock_t *lock) +{ + int err; + + err = pthread_mutex_init (&lock->mutex, NULL); + if (err != 0) + return err; + lock->owner = (pthread_t) 0; + lock->depth = 0; + return 0; +} + +int +glthread_recursive_lock_lock_multithreaded (gl_recursive_lock_t *lock) +{ + pthread_t self = pthread_self (); + if (lock->owner != self) + { + int err; + + err = pthread_mutex_lock (&lock->mutex); + if (err != 0) + return err; + lock->owner = self; + } + if (++(lock->depth) == 0) /* wraparound? */ + { + lock->depth--; + return EAGAIN; + } + return 0; +} + +int +glthread_recursive_lock_unlock_multithreaded (gl_recursive_lock_t *lock) +{ + if (lock->owner != pthread_self ()) + return EPERM; + if (lock->depth == 0) + return EINVAL; + if (--(lock->depth) == 0) + { + lock->owner = (pthread_t) 0; + return pthread_mutex_unlock (&lock->mutex); + } + else + return 0; +} + +int +glthread_recursive_lock_destroy_multithreaded (gl_recursive_lock_t *lock) +{ + if (lock->owner != (pthread_t) 0) + return EBUSY; + return pthread_mutex_destroy (&lock->mutex); +} + +# endif + +/* -------------------------- gl_once_t datatype -------------------------- */ + +static const pthread_once_t fresh_once = PTHREAD_ONCE_INIT; + +int +glthread_once_singlethreaded (pthread_once_t *once_control) +{ + /* We don't know whether pthread_once_t is an integer type, a floating-point + type, a pointer type, or a structure type. */ + char *firstbyte = (char *)once_control; + if (*firstbyte == *(const char *)&fresh_once) + { + /* First time use of once_control. Invert the first byte. */ + *firstbyte = ~ *(const char *)&fresh_once; + return 1; + } + else + return 0; +} + +#endif + +/* ========================================================================= */ + +#if USE_PTH_THREADS + +/* Use the GNU Pth threads library. */ + +/* -------------------------- gl_lock_t datatype -------------------------- */ + +/* ------------------------- gl_rwlock_t datatype ------------------------- */ + +/* --------------------- gl_recursive_lock_t datatype --------------------- */ + +/* -------------------------- gl_once_t datatype -------------------------- */ + +static void +glthread_once_call (void *arg) +{ + void (**gl_once_temp_addr) (void) = (void (**) (void)) arg; + void (*initfunction) (void) = *gl_once_temp_addr; + initfunction (); +} + +int +glthread_once_multithreaded (pth_once_t *once_control, void (*initfunction) (void)) +{ + void (*temp) (void) = initfunction; + return (!pth_once (once_control, glthread_once_call, &temp) ? errno : 0); +} + +int +glthread_once_singlethreaded (pth_once_t *once_control) +{ + /* We know that pth_once_t is an integer type. */ + if (*once_control == PTH_ONCE_INIT) + { + /* First time use of once_control. Invert the marker. */ + *once_control = ~ PTH_ONCE_INIT; + return 1; + } + else + return 0; +} + +#endif + +/* ========================================================================= */ + +#if USE_SOLARIS_THREADS + +/* Use the old Solaris threads library. */ + +/* -------------------------- gl_lock_t datatype -------------------------- */ + +/* ------------------------- gl_rwlock_t datatype ------------------------- */ + +/* --------------------- gl_recursive_lock_t datatype --------------------- */ + +int +glthread_recursive_lock_init_multithreaded (gl_recursive_lock_t *lock) +{ + int err; + + err = mutex_init (&lock->mutex, USYNC_THREAD, NULL); + if (err != 0) + return err; + lock->owner = (thread_t) 0; + lock->depth = 0; + return 0; +} + +int +glthread_recursive_lock_lock_multithreaded (gl_recursive_lock_t *lock) +{ + thread_t self = thr_self (); + if (lock->owner != self) + { + int err; + + err = mutex_lock (&lock->mutex); + if (err != 0) + return err; + lock->owner = self; + } + if (++(lock->depth) == 0) /* wraparound? */ + { + lock->depth--; + return EAGAIN; + } + return 0; +} + +int +glthread_recursive_lock_unlock_multithreaded (gl_recursive_lock_t *lock) +{ + if (lock->owner != thr_self ()) + return EPERM; + if (lock->depth == 0) + return EINVAL; + if (--(lock->depth) == 0) + { + lock->owner = (thread_t) 0; + return mutex_unlock (&lock->mutex); + } + else + return 0; +} + +int +glthread_recursive_lock_destroy_multithreaded (gl_recursive_lock_t *lock) +{ + if (lock->owner != (thread_t) 0) + return EBUSY; + return mutex_destroy (&lock->mutex); +} + +/* -------------------------- gl_once_t datatype -------------------------- */ + +int +glthread_once_multithreaded (gl_once_t *once_control, void (*initfunction) (void)) +{ + if (!once_control->inited) + { + int err; + + /* Use the mutex to guarantee that if another thread is already calling + the initfunction, this thread waits until it's finished. */ + err = mutex_lock (&once_control->mutex); + if (err != 0) + return err; + if (!once_control->inited) + { + once_control->inited = 1; + initfunction (); + } + return mutex_unlock (&once_control->mutex); + } + else + return 0; +} + +int +glthread_once_singlethreaded (gl_once_t *once_control) +{ + /* We know that gl_once_t contains an integer type. */ + if (!once_control->inited) + { + /* First time use of once_control. Invert the marker. */ + once_control->inited = ~ 0; + return 1; + } + else + return 0; +} + +#endif + +/* ========================================================================= */ + +#if USE_WIN32_THREADS + +/* -------------------------- gl_lock_t datatype -------------------------- */ + +void +glthread_lock_init_func (gl_lock_t *lock) +{ + InitializeCriticalSection (&lock->lock); + lock->guard.done = 1; +} + +int +glthread_lock_lock_func (gl_lock_t *lock) +{ + if (!lock->guard.done) + { + if (InterlockedIncrement (&lock->guard.started) == 0) + /* This thread is the first one to need this lock. Initialize it. */ + glthread_lock_init (lock); + else + /* Yield the CPU while waiting for another thread to finish + initializing this lock. */ + while (!lock->guard.done) + Sleep (0); + } + EnterCriticalSection (&lock->lock); + return 0; +} + +int +glthread_lock_unlock_func (gl_lock_t *lock) +{ + if (!lock->guard.done) + return EINVAL; + LeaveCriticalSection (&lock->lock); + return 0; +} + +int +glthread_lock_destroy_func (gl_lock_t *lock) +{ + if (!lock->guard.done) + return EINVAL; + DeleteCriticalSection (&lock->lock); + lock->guard.done = 0; + return 0; +} + +/* ------------------------- gl_rwlock_t datatype ------------------------- */ + +/* In this file, the waitqueues are implemented as circular arrays. */ +#define gl_waitqueue_t gl_carray_waitqueue_t + +static inline void +gl_waitqueue_init (gl_waitqueue_t *wq) +{ + wq->array = NULL; + wq->count = 0; + wq->alloc = 0; + wq->offset = 0; +} + +/* Enqueues the current thread, represented by an event, in a wait queue. + Returns INVALID_HANDLE_VALUE if an allocation failure occurs. */ +static HANDLE +gl_waitqueue_add (gl_waitqueue_t *wq) +{ + HANDLE event; + unsigned int index; + + if (wq->count == wq->alloc) + { + unsigned int new_alloc = 2 * wq->alloc + 1; + HANDLE *new_array = + (HANDLE *) realloc (wq->array, new_alloc * sizeof (HANDLE)); + if (new_array == NULL) + /* No more memory. */ + return INVALID_HANDLE_VALUE; + /* Now is a good opportunity to rotate the array so that its contents + starts at offset 0. */ + if (wq->offset > 0) + { + unsigned int old_count = wq->count; + unsigned int old_alloc = wq->alloc; + unsigned int old_offset = wq->offset; + unsigned int i; + if (old_offset + old_count > old_alloc) + { + unsigned int limit = old_offset + old_count - old_alloc; + for (i = 0; i < limit; i++) + new_array[old_alloc + i] = new_array[i]; + } + for (i = 0; i < old_count; i++) + new_array[i] = new_array[old_offset + i]; + wq->offset = 0; + } + wq->array = new_array; + wq->alloc = new_alloc; + } + /* Whether the created event is a manual-reset one or an auto-reset one, + does not matter, since we will wait on it only once. */ + event = CreateEvent (NULL, TRUE, FALSE, NULL); + if (event == INVALID_HANDLE_VALUE) + /* No way to allocate an event. */ + return INVALID_HANDLE_VALUE; + index = wq->offset + wq->count; + if (index >= wq->alloc) + index -= wq->alloc; + wq->array[index] = event; + wq->count++; + return event; +} + +/* Notifies the first thread from a wait queue and dequeues it. */ +static inline void +gl_waitqueue_notify_first (gl_waitqueue_t *wq) +{ + SetEvent (wq->array[wq->offset + 0]); + wq->offset++; + wq->count--; + if (wq->count == 0 || wq->offset == wq->alloc) + wq->offset = 0; +} + +/* Notifies all threads from a wait queue and dequeues them all. */ +static inline void +gl_waitqueue_notify_all (gl_waitqueue_t *wq) +{ + unsigned int i; + + for (i = 0; i < wq->count; i++) + { + unsigned int index = wq->offset + i; + if (index >= wq->alloc) + index -= wq->alloc; + SetEvent (wq->array[index]); + } + wq->count = 0; + wq->offset = 0; +} + +void +glthread_rwlock_init_func (gl_rwlock_t *lock) +{ + InitializeCriticalSection (&lock->lock); + gl_waitqueue_init (&lock->waiting_readers); + gl_waitqueue_init (&lock->waiting_writers); + lock->runcount = 0; + lock->guard.done = 1; +} + +int +glthread_rwlock_rdlock_func (gl_rwlock_t *lock) +{ + if (!lock->guard.done) + { + if (InterlockedIncrement (&lock->guard.started) == 0) + /* This thread is the first one to need this lock. Initialize it. */ + glthread_rwlock_init (lock); + else + /* Yield the CPU while waiting for another thread to finish + initializing this lock. */ + while (!lock->guard.done) + Sleep (0); + } + EnterCriticalSection (&lock->lock); + /* Test whether only readers are currently running, and whether the runcount + field will not overflow. */ + if (!(lock->runcount + 1 > 0)) + { + /* This thread has to wait for a while. Enqueue it among the + waiting_readers. */ + HANDLE event = gl_waitqueue_add (&lock->waiting_readers); + if (event != INVALID_HANDLE_VALUE) + { + DWORD result; + LeaveCriticalSection (&lock->lock); + /* Wait until another thread signals this event. */ + result = WaitForSingleObject (event, INFINITE); + if (result == WAIT_FAILED || result == WAIT_TIMEOUT) + abort (); + CloseHandle (event); + /* The thread which signalled the event already did the bookkeeping: + removed us from the waiting_readers, incremented lock->runcount. */ + if (!(lock->runcount > 0)) + abort (); + return 0; + } + else + { + /* Allocation failure. Weird. */ + do + { + LeaveCriticalSection (&lock->lock); + Sleep (1); + EnterCriticalSection (&lock->lock); + } + while (!(lock->runcount + 1 > 0)); + } + } + lock->runcount++; + LeaveCriticalSection (&lock->lock); + return 0; +} + +int +glthread_rwlock_wrlock_func (gl_rwlock_t *lock) +{ + if (!lock->guard.done) + { + if (InterlockedIncrement (&lock->guard.started) == 0) + /* This thread is the first one to need this lock. Initialize it. */ + glthread_rwlock_init (lock); + else + /* Yield the CPU while waiting for another thread to finish + initializing this lock. */ + while (!lock->guard.done) + Sleep (0); + } + EnterCriticalSection (&lock->lock); + /* Test whether no readers or writers are currently running. */ + if (!(lock->runcount == 0)) + { + /* This thread has to wait for a while. Enqueue it among the + waiting_writers. */ + HANDLE event = gl_waitqueue_add (&lock->waiting_writers); + if (event != INVALID_HANDLE_VALUE) + { + DWORD result; + LeaveCriticalSection (&lock->lock); + /* Wait until another thread signals this event. */ + result = WaitForSingleObject (event, INFINITE); + if (result == WAIT_FAILED || result == WAIT_TIMEOUT) + abort (); + CloseHandle (event); + /* The thread which signalled the event already did the bookkeeping: + removed us from the waiting_writers, set lock->runcount = -1. */ + if (!(lock->runcount == -1)) + abort (); + return 0; + } + else + { + /* Allocation failure. Weird. */ + do + { + LeaveCriticalSection (&lock->lock); + Sleep (1); + EnterCriticalSection (&lock->lock); + } + while (!(lock->runcount == 0)); + } + } + lock->runcount--; /* runcount becomes -1 */ + LeaveCriticalSection (&lock->lock); + return 0; +} + +int +glthread_rwlock_unlock_func (gl_rwlock_t *lock) +{ + if (!lock->guard.done) + return EINVAL; + EnterCriticalSection (&lock->lock); + if (lock->runcount < 0) + { + /* Drop a writer lock. */ + if (!(lock->runcount == -1)) + abort (); + lock->runcount = 0; + } + else + { + /* Drop a reader lock. */ + if (!(lock->runcount > 0)) + { + LeaveCriticalSection (&lock->lock); + return EPERM; + } + lock->runcount--; + } + if (lock->runcount == 0) + { + /* POSIX recommends that "write locks shall take precedence over read + locks", to avoid "writer starvation". */ + if (lock->waiting_writers.count > 0) + { + /* Wake up one of the waiting writers. */ + lock->runcount--; + gl_waitqueue_notify_first (&lock->waiting_writers); + } + else + { + /* Wake up all waiting readers. */ + lock->runcount += lock->waiting_readers.count; + gl_waitqueue_notify_all (&lock->waiting_readers); + } + } + LeaveCriticalSection (&lock->lock); + return 0; +} + +int +glthread_rwlock_destroy_func (gl_rwlock_t *lock) +{ + if (!lock->guard.done) + return EINVAL; + if (lock->runcount != 0) + return EBUSY; + DeleteCriticalSection (&lock->lock); + if (lock->waiting_readers.array != NULL) + free (lock->waiting_readers.array); + if (lock->waiting_writers.array != NULL) + free (lock->waiting_writers.array); + lock->guard.done = 0; + return 0; +} + +/* --------------------- gl_recursive_lock_t datatype --------------------- */ + +void +glthread_recursive_lock_init_func (gl_recursive_lock_t *lock) +{ + lock->owner = 0; + lock->depth = 0; + InitializeCriticalSection (&lock->lock); + lock->guard.done = 1; +} + +int +glthread_recursive_lock_lock_func (gl_recursive_lock_t *lock) +{ + if (!lock->guard.done) + { + if (InterlockedIncrement (&lock->guard.started) == 0) + /* This thread is the first one to need this lock. Initialize it. */ + glthread_recursive_lock_init (lock); + else + /* Yield the CPU while waiting for another thread to finish + initializing this lock. */ + while (!lock->guard.done) + Sleep (0); + } + { + DWORD self = GetCurrentThreadId (); + if (lock->owner != self) + { + EnterCriticalSection (&lock->lock); + lock->owner = self; + } + if (++(lock->depth) == 0) /* wraparound? */ + { + lock->depth--; + return EAGAIN; + } + } + return 0; +} + +int +glthread_recursive_lock_unlock_func (gl_recursive_lock_t *lock) +{ + if (lock->owner != GetCurrentThreadId ()) + return EPERM; + if (lock->depth == 0) + return EINVAL; + if (--(lock->depth) == 0) + { + lock->owner = 0; + LeaveCriticalSection (&lock->lock); + } + return 0; +} + +int +glthread_recursive_lock_destroy_func (gl_recursive_lock_t *lock) +{ + if (lock->owner != 0) + return EBUSY; + DeleteCriticalSection (&lock->lock); + lock->guard.done = 0; + return 0; +} + +/* -------------------------- gl_once_t datatype -------------------------- */ + +void +glthread_once_func (gl_once_t *once_control, void (*initfunction) (void)) +{ + if (once_control->inited <= 0) + { + if (InterlockedIncrement (&once_control->started) == 0) + { + /* This thread is the first one to come to this once_control. */ + InitializeCriticalSection (&once_control->lock); + EnterCriticalSection (&once_control->lock); + once_control->inited = 0; + initfunction (); + once_control->inited = 1; + LeaveCriticalSection (&once_control->lock); + } + else + { + /* Undo last operation. */ + InterlockedDecrement (&once_control->started); + /* Some other thread has already started the initialization. + Yield the CPU while waiting for the other thread to finish + initializing and taking the lock. */ + while (once_control->inited < 0) + Sleep (0); + if (once_control->inited <= 0) + { + /* Take the lock. This blocks until the other thread has + finished calling the initfunction. */ + EnterCriticalSection (&once_control->lock); + LeaveCriticalSection (&once_control->lock); + if (!(once_control->inited > 0)) + abort (); + } + } + } +} + +#endif + +/* ========================================================================= */ diff --git a/lib/glthread/lock.h b/lib/glthread/lock.h new file mode 100644 index 00000000..47ce7738 --- /dev/null +++ b/lib/glthread/lock.h @@ -0,0 +1,927 @@ +/* Locking in multithreaded situations. + Copyright (C) 2005-2010 Free Software Foundation, Inc. + + This program 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, or (at your option) + any later version. + + This program 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 this program; if not, write to the Free Software Foundation, + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + +/* Written by Bruno Haible <bruno@clisp.org>, 2005. + Based on GCC's gthr-posix.h, gthr-posix95.h, gthr-solaris.h, + gthr-win32.h. */ + +/* This file contains locking primitives for use with a given thread library. + It does not contain primitives for creating threads or for other + synchronization primitives. + + Normal (non-recursive) locks: + Type: gl_lock_t + Declaration: gl_lock_define(extern, name) + Initializer: gl_lock_define_initialized(, name) + Initialization: gl_lock_init (name); + Taking the lock: gl_lock_lock (name); + Releasing the lock: gl_lock_unlock (name); + De-initialization: gl_lock_destroy (name); + Equivalent functions with control of error handling: + Initialization: err = glthread_lock_init (&name); + Taking the lock: err = glthread_lock_lock (&name); + Releasing the lock: err = glthread_lock_unlock (&name); + De-initialization: err = glthread_lock_destroy (&name); + + Read-Write (non-recursive) locks: + Type: gl_rwlock_t + Declaration: gl_rwlock_define(extern, name) + Initializer: gl_rwlock_define_initialized(, name) + Initialization: gl_rwlock_init (name); + Taking the lock: gl_rwlock_rdlock (name); + gl_rwlock_wrlock (name); + Releasing the lock: gl_rwlock_unlock (name); + De-initialization: gl_rwlock_destroy (name); + Equivalent functions with control of error handling: + Initialization: err = glthread_rwlock_init (&name); + Taking the lock: err = glthread_rwlock_rdlock (&name); + err = glthread_rwlock_wrlock (&name); + Releasing the lock: err = glthread_rwlock_unlock (&name); + De-initialization: err = glthread_rwlock_destroy (&name); + + Recursive locks: + Type: gl_recursive_lock_t + Declaration: gl_recursive_lock_define(extern, name) + Initializer: gl_recursive_lock_define_initialized(, name) + Initialization: gl_recursive_lock_init (name); + Taking the lock: gl_recursive_lock_lock (name); + Releasing the lock: gl_recursive_lock_unlock (name); + De-initialization: gl_recursive_lock_destroy (name); + Equivalent functions with control of error handling: + Initialization: err = glthread_recursive_lock_init (&name); + Taking the lock: err = glthread_recursive_lock_lock (&name); + Releasing the lock: err = glthread_recursive_lock_unlock (&name); + De-initialization: err = glthread_recursive_lock_destroy (&name); + + Once-only execution: + Type: gl_once_t + Initializer: gl_once_define(extern, name) + Execution: gl_once (name, initfunction); + Equivalent functions with control of error handling: + Execution: err = glthread_once (&name, initfunction); +*/ + + +#ifndef _LOCK_H +#define _LOCK_H + +#include <errno.h> +#include <stdlib.h> + +/* ========================================================================= */ + +#if USE_POSIX_THREADS + +/* Use the POSIX threads library. */ + +# include <pthread.h> + +# ifdef __cplusplus +extern "C" { +# endif + +# if PTHREAD_IN_USE_DETECTION_HARD + +/* The pthread_in_use() detection needs to be done at runtime. */ +# define pthread_in_use() \ + glthread_in_use () +extern int glthread_in_use (void); + +# endif + +# if USE_POSIX_THREADS_WEAK + +/* Use weak references to the POSIX threads library. */ + +/* Weak references avoid dragging in external libraries if the other parts + of the program don't use them. Here we use them, because we don't want + every program that uses libintl to depend on libpthread. This assumes + that libpthread would not be loaded after libintl; i.e. if libintl is + loaded first, by an executable that does not depend on libpthread, and + then a module is dynamically loaded that depends on libpthread, libintl + will not be multithread-safe. */ + +/* The way to test at runtime whether libpthread is present is to test + whether a function pointer's value, such as &pthread_mutex_init, is + non-NULL. However, some versions of GCC have a bug through which, in + PIC mode, &foo != NULL always evaluates to true if there is a direct + call to foo(...) in the same function. To avoid this, we test the + address of a function in libpthread that we don't use. */ + +# pragma weak pthread_mutex_init +# pragma weak pthread_mutex_lock +# pragma weak pthread_mutex_unlock +# pragma weak pthread_mutex_destroy +# pragma weak pthread_rwlock_init +# pragma weak pthread_rwlock_rdlock +# pragma weak pthread_rwlock_wrlock +# pragma weak pthread_rwlock_unlock +# pragma weak pthread_rwlock_destroy +# pragma weak pthread_once +# pragma weak pthread_cond_init +# pragma weak pthread_cond_wait +# pragma weak pthread_cond_signal +# pragma weak pthread_cond_broadcast +# pragma weak pthread_cond_destroy +# pragma weak pthread_mutexattr_init +# pragma weak pthread_mutexattr_settype +# pragma weak pthread_mutexattr_destroy +# ifndef pthread_self +# pragma weak pthread_self +# endif + +# if !PTHREAD_IN_USE_DETECTION_HARD +# pragma weak pthread_cancel +# define pthread_in_use() (pthread_cancel != NULL) +# endif + +# else + +# if !PTHREAD_IN_USE_DETECTION_HARD +# define pthread_in_use() 1 +# endif + +# endif + +/* -------------------------- gl_lock_t datatype -------------------------- */ + +typedef pthread_mutex_t gl_lock_t; +# define gl_lock_define(STORAGECLASS, NAME) \ + STORAGECLASS pthread_mutex_t NAME; +# define gl_lock_define_initialized(STORAGECLASS, NAME) \ + STORAGECLASS pthread_mutex_t NAME = gl_lock_initializer; +# define gl_lock_initializer \ + PTHREAD_MUTEX_INITIALIZER +# define glthread_lock_init(LOCK) \ + (pthread_in_use () ? pthread_mutex_init (LOCK, NULL) : 0) +# define glthread_lock_lock(LOCK) \ + (pthread_in_use () ? pthread_mutex_lock (LOCK) : 0) +# define glthread_lock_unlock(LOCK) \ + (pthread_in_use () ? pthread_mutex_unlock (LOCK) : 0) +# define glthread_lock_destroy(LOCK) \ + (pthread_in_use () ? pthread_mutex_destroy (LOCK) : 0) + +/* ------------------------- gl_rwlock_t datatype ------------------------- */ + +# if HAVE_PTHREAD_RWLOCK + +# ifdef PTHREAD_RWLOCK_INITIALIZER + +typedef pthread_rwlock_t gl_rwlock_t; +# define gl_rwlock_define(STORAGECLASS, NAME) \ + STORAGECLASS pthread_rwlock_t NAME; +# define gl_rwlock_define_initialized(STORAGECLASS, NAME) \ + STORAGECLASS pthread_rwlock_t NAME = gl_rwlock_initializer; +# define gl_rwlock_initializer \ + PTHREAD_RWLOCK_INITIALIZER +# define glthread_rwlock_init(LOCK) \ + (pthread_in_use () ? pthread_rwlock_init (LOCK, NULL) : 0) +# define glthread_rwlock_rdlock(LOCK) \ + (pthread_in_use () ? pthread_rwlock_rdlock (LOCK) : 0) +# define glthread_rwlock_wrlock(LOCK) \ + (pthread_in_use () ? pthread_rwlock_wrlock (LOCK) : 0) +# define glthread_rwlock_unlock(LOCK) \ + (pthread_in_use () ? pthread_rwlock_unlock (LOCK) : 0) +# define glthread_rwlock_destroy(LOCK) \ + (pthread_in_use () ? pthread_rwlock_destroy (LOCK) : 0) + +# else + +typedef struct + { + int initialized; + pthread_mutex_t guard; /* protects the initialization */ + pthread_rwlock_t rwlock; /* read-write lock */ + } + gl_rwlock_t; +# define gl_rwlock_define(STORAGECLASS, NAME) \ + STORAGECLASS gl_rwlock_t NAME; +# define gl_rwlock_define_initialized(STORAGECLASS, NAME) \ + STORAGECLASS gl_rwlock_t NAME = gl_rwlock_initializer; +# define gl_rwlock_initializer \ + { 0, PTHREAD_MUTEX_INITIALIZER } +# define glthread_rwlock_init(LOCK) \ + (pthread_in_use () ? glthread_rwlock_init_multithreaded (LOCK) : 0) +# define glthread_rwlock_rdlock(LOCK) \ + (pthread_in_use () ? glthread_rwlock_rdlock_multithreaded (LOCK) : 0) +# define glthread_rwlock_wrlock(LOCK) \ + (pthread_in_use () ? glthread_rwlock_wrlock_multithreaded (LOCK) : 0) +# define glthread_rwlock_unlock(LOCK) \ + (pthread_in_use () ? glthread_rwlock_unlock_multithreaded (LOCK) : 0) +# define glthread_rwlock_destroy(LOCK) \ + (pthread_in_use () ? glthread_rwlock_destroy_multithreaded (LOCK) : 0) +extern int glthread_rwlock_init_multithreaded (gl_rwlock_t *lock); +extern int glthread_rwlock_rdlock_multithreaded (gl_rwlock_t *lock); +extern int glthread_rwlock_wrlock_multithreaded (gl_rwlock_t *lock); +extern int glthread_rwlock_unlock_multithreaded (gl_rwlock_t *lock); +extern int glthread_rwlock_destroy_multithreaded (gl_rwlock_t *lock); + +# endif + +# else + +typedef struct + { + pthread_mutex_t lock; /* protects the remaining fields */ + pthread_cond_t waiting_readers; /* waiting readers */ + pthread_cond_t waiting_writers; /* waiting writers */ + unsigned int waiting_writers_count; /* number of waiting writers */ + int runcount; /* number of readers running, or -1 when a writer runs */ + } + gl_rwlock_t; +# define gl_rwlock_define(STORAGECLASS, NAME) \ + STORAGECLASS gl_rwlock_t NAME; +# define gl_rwlock_define_initialized(STORAGECLASS, NAME) \ + STORAGECLASS gl_rwlock_t NAME = gl_rwlock_initializer; +# define gl_rwlock_initializer \ + { PTHREAD_MUTEX_INITIALIZER, PTHREAD_COND_INITIALIZER, PTHREAD_COND_INITIALIZER, 0, 0 } +# define glthread_rwlock_init(LOCK) \ + (pthread_in_use () ? glthread_rwlock_init_multithreaded (LOCK) : 0) +# define glthread_rwlock_rdlock(LOCK) \ + (pthread_in_use () ? glthread_rwlock_rdlock_multithreaded (LOCK) : 0) +# define glthread_rwlock_wrlock(LOCK) \ + (pthread_in_use () ? glthread_rwlock_wrlock_multithreaded (LOCK) : 0) +# define glthread_rwlock_unlock(LOCK) \ + (pthread_in_use () ? glthread_rwlock_unlock_multithreaded (LOCK) : 0) +# define glthread_rwlock_destroy(LOCK) \ + (pthread_in_use () ? glthread_rwlock_destroy_multithreaded (LOCK) : 0) +extern int glthread_rwlock_init_multithreaded (gl_rwlock_t *lock); +extern int glthread_rwlock_rdlock_multithreaded (gl_rwlock_t *lock); +extern int glthread_rwlock_wrlock_multithreaded (gl_rwlock_t *lock); +extern int glthread_rwlock_unlock_multithreaded (gl_rwlock_t *lock); +extern int glthread_rwlock_destroy_multithreaded (gl_rwlock_t *lock); + +# endif + +/* --------------------- gl_recursive_lock_t datatype --------------------- */ + +# if HAVE_PTHREAD_MUTEX_RECURSIVE + +# if defined PTHREAD_RECURSIVE_MUTEX_INITIALIZER || defined PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP + +typedef pthread_mutex_t gl_recursive_lock_t; +# define gl_recursive_lock_define(STORAGECLASS, NAME) \ + STORAGECLASS pthread_mutex_t NAME; +# define gl_recursive_lock_define_initialized(STORAGECLASS, NAME) \ + STORAGECLASS pthread_mutex_t NAME = gl_recursive_lock_initializer; +# ifdef PTHREAD_RECURSIVE_MUTEX_INITIALIZER +# define gl_recursive_lock_initializer \ + PTHREAD_RECURSIVE_MUTEX_INITIALIZER +# else +# define gl_recursive_lock_initializer \ + PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP +# endif +# define glthread_recursive_lock_init(LOCK) \ + (pthread_in_use () ? glthread_recursive_lock_init_multithreaded (LOCK) : 0) +# define glthread_recursive_lock_lock(LOCK) \ + (pthread_in_use () ? pthread_mutex_lock (LOCK) : 0) +# define glthread_recursive_lock_unlock(LOCK) \ + (pthread_in_use () ? pthread_mutex_unlock (LOCK) : 0) +# define glthread_recursive_lock_destroy(LOCK) \ + (pthread_in_use () ? pthread_mutex_destroy (LOCK) : 0) +extern int glthread_recursive_lock_init_multithreaded (gl_recursive_lock_t *lock); + +# else + +typedef struct + { + pthread_mutex_t recmutex; /* recursive mutex */ + pthread_mutex_t guard; /* protects the initialization */ + int initialized; + } + gl_recursive_lock_t; +# define gl_recursive_lock_define(STORAGECLASS, NAME) \ + STORAGECLASS gl_recursive_lock_t NAME; +# define gl_recursive_lock_define_initialized(STORAGECLASS, NAME) \ + STORAGECLASS gl_recursive_lock_t NAME = gl_recursive_lock_initializer; +# define gl_recursive_lock_initializer \ + { PTHREAD_MUTEX_INITIALIZER, PTHREAD_MUTEX_INITIALIZER, 0 } +# define glthread_recursive_lock_init(LOCK) \ + (pthread_in_use () ? glthread_recursive_lock_init_multithreaded (LOCK) : 0) +# define glthread_recursive_lock_lock(LOCK) \ + (pthread_in_use () ? glthread_recursive_lock_lock_multithreaded (LOCK) : 0) +# define glthread_recursive_lock_unlock(LOCK) \ + (pthread_in_use () ? glthread_recursive_lock_unlock_multithreaded (LOCK) : 0) +# define glthread_recursive_lock_destroy(LOCK) \ + (pthread_in_use () ? glthread_recursive_lock_destroy_multithreaded (LOCK) : 0) +extern int glthread_recursive_lock_init_multithreaded (gl_recursive_lock_t *lock); +extern int glthread_recursive_lock_lock_multithreaded (gl_recursive_lock_t *lock); +extern int glthread_recursive_lock_unlock_multithreaded (gl_recursive_lock_t *lock); +extern int glthread_recursive_lock_destroy_multithreaded (gl_recursive_lock_t *lock); + +# endif + +# else + +/* Old versions of POSIX threads on Solaris did not have recursive locks. + We have to implement them ourselves. */ + +typedef struct + { + pthread_mutex_t mutex; + pthread_t owner; + unsigned long depth; + } + gl_recursive_lock_t; +# define gl_recursive_lock_define(STORAGECLASS, NAME) \ + STORAGECLASS gl_recursive_lock_t NAME; +# define gl_recursive_lock_define_initialized(STORAGECLASS, NAME) \ + STORAGECLASS gl_recursive_lock_t NAME = gl_recursive_lock_initializer; +# define gl_recursive_lock_initializer \ + { PTHREAD_MUTEX_INITIALIZER, (pthread_t) 0, 0 } +# define glthread_recursive_lock_init(LOCK) \ + (pthread_in_use () ? glthread_recursive_lock_init_multithreaded (LOCK) : 0) +# define glthread_recursive_lock_lock(LOCK) \ + (pthread_in_use () ? glthread_recursive_lock_lock_multithreaded (LOCK) : 0) +# define glthread_recursive_lock_unlock(LOCK) \ + (pthread_in_use () ? glthread_recursive_lock_unlock_multithreaded (LOCK) : 0) +# define glthread_recursive_lock_destroy(LOCK) \ + (pthread_in_use () ? glthread_recursive_lock_destroy_multithreaded (LOCK) : 0) +extern int glthread_recursive_lock_init_multithreaded (gl_recursive_lock_t *lock); +extern int glthread_recursive_lock_lock_multithreaded (gl_recursive_lock_t *lock); +extern int glthread_recursive_lock_unlock_multithreaded (gl_recursive_lock_t *lock); +extern int glthread_recursive_lock_destroy_multithreaded (gl_recursive_lock_t *lock); + +# endif + +/* -------------------------- gl_once_t datatype -------------------------- */ + +typedef pthread_once_t gl_once_t; +# define gl_once_define(STORAGECLASS, NAME) \ + STORAGECLASS pthread_once_t NAME = PTHREAD_ONCE_INIT; +# define glthread_once(ONCE_CONTROL, INITFUNCTION) \ + (pthread_in_use () \ + ? pthread_once (ONCE_CONTROL, INITFUNCTION) \ + : (glthread_once_singlethreaded (ONCE_CONTROL) ? (INITFUNCTION (), 0) : 0)) +extern int glthread_once_singlethreaded (pthread_once_t *once_control); + +# ifdef __cplusplus +} +# endif + +#endif + +/* ========================================================================= */ + +#if USE_PTH_THREADS + +/* Use the GNU Pth threads library. */ + +# include <pth.h> + +# ifdef __cplusplus +extern "C" { +# endif + +# if USE_PTH_THREADS_WEAK + +/* Use weak references to the GNU Pth threads library. */ + +# pragma weak pth_mutex_init +# pragma weak pth_mutex_acquire +# pragma weak pth_mutex_release +# pragma weak pth_rwlock_init +# pragma weak pth_rwlock_acquire +# pragma weak pth_rwlock_release +# pragma weak pth_once + +# pragma weak pth_cancel +# define pth_in_use() (pth_cancel != NULL) + +# else + +# define pth_in_use() 1 + +# endif + +/* -------------------------- gl_lock_t datatype -------------------------- */ + +typedef pth_mutex_t gl_lock_t; +# define gl_lock_define(STORAGECLASS, NAME) \ + STORAGECLASS pth_mutex_t NAME; +# define gl_lock_define_initialized(STORAGECLASS, NAME) \ + STORAGECLASS pth_mutex_t NAME = gl_lock_initializer; +# define gl_lock_initializer \ + PTH_MUTEX_INIT +# define glthread_lock_init(LOCK) \ + (pth_in_use () && !pth_mutex_init (LOCK) ? errno : 0) +# define glthread_lock_lock(LOCK) \ + (pth_in_use () && !pth_mutex_acquire (LOCK, 0, NULL) ? errno : 0) +# define glthread_lock_unlock(LOCK) \ + (pth_in_use () && !pth_mutex_release (LOCK) ? errno : 0) +# define glthread_lock_destroy(LOCK) \ + ((void)(LOCK), 0) + +/* ------------------------- gl_rwlock_t datatype ------------------------- */ + +typedef pth_rwlock_t gl_rwlock_t; +# define gl_rwlock_define(STORAGECLASS, NAME) \ + STORAGECLASS pth_rwlock_t NAME; +# define gl_rwlock_define_initialized(STORAGECLASS, NAME) \ + STORAGECLASS pth_rwlock_t NAME = gl_rwlock_initializer; +# define gl_rwlock_initializer \ + PTH_RWLOCK_INIT +# define glthread_rwlock_init(LOCK) \ + (pth_in_use () && !pth_rwlock_init (LOCK) ? errno : 0) +# define glthread_rwlock_rdlock(LOCK) \ + (pth_in_use () && !pth_rwlock_acquire (LOCK, PTH_RWLOCK_RD, 0, NULL) ? errno : 0) +# define glthread_rwlock_wrlock(LOCK) \ + (pth_in_use () && !pth_rwlock_acquire (LOCK, PTH_RWLOCK_RW, 0, NULL) ? errno : 0) +# define glthread_rwlock_unlock(LOCK) \ + (pth_in_use () && !pth_rwlock_release (LOCK) ? errno : 0) +# define glthread_rwlock_destroy(LOCK) \ + ((void)(LOCK), 0) + +/* --------------------- gl_recursive_lock_t datatype --------------------- */ + +/* In Pth, mutexes are recursive by default. */ +typedef pth_mutex_t gl_recursive_lock_t; +# define gl_recursive_lock_define(STORAGECLASS, NAME) \ + STORAGECLASS pth_mutex_t NAME; +# define gl_recursive_lock_define_initialized(STORAGECLASS, NAME) \ + STORAGECLASS pth_mutex_t NAME = gl_recursive_lock_initializer; +# define gl_recursive_lock_initializer \ + PTH_MUTEX_INIT +# define glthread_recursive_lock_init(LOCK) \ + (pth_in_use () && !pth_mutex_init (LOCK) ? errno : 0) +# define glthread_recursive_lock_lock(LOCK) \ + (pth_in_use () && !pth_mutex_acquire (LOCK, 0, NULL) ? errno : 0) +# define glthread_recursive_lock_unlock(LOCK) \ + (pth_in_use () && !pth_mutex_release (LOCK) ? errno : 0) +# define glthread_recursive_lock_destroy(LOCK) \ + ((void)(LOCK), 0) + +/* -------------------------- gl_once_t datatype -------------------------- */ + +typedef pth_once_t gl_once_t; +# define gl_once_define(STORAGECLASS, NAME) \ + STORAGECLASS pth_once_t NAME = PTH_ONCE_INIT; +# define glthread_once(ONCE_CONTROL, INITFUNCTION) \ + (pth_in_use () \ + ? glthread_once_multithreaded (ONCE_CONTROL, INITFUNCTION) \ + : (glthread_once_singlethreaded (ONCE_CONTROL) ? (INITFUNCTION (), 0) : 0)) +extern int glthread_once_multithreaded (pth_once_t *once_control, void (*initfunction) (void)); +extern int glthread_once_singlethreaded (pth_once_t *once_control); + +# ifdef __cplusplus +} +# endif + +#endif + +/* ========================================================================= */ + +#if USE_SOLARIS_THREADS + +/* Use the old Solaris threads library. */ + +# include <thread.h> +# include <synch.h> + +# ifdef __cplusplus +extern "C" { +# endif + +# if USE_SOLARIS_THREADS_WEAK + +/* Use weak references to the old Solaris threads library. */ + +# pragma weak mutex_init +# pragma weak mutex_lock +# pragma weak mutex_unlock +# pragma weak mutex_destroy +# pragma weak rwlock_init +# pragma weak rw_rdlock +# pragma weak rw_wrlock +# pragma weak rw_unlock +# pragma weak rwlock_destroy +# pragma weak thr_self + +# pragma weak thr_suspend +# define thread_in_use() (thr_suspend != NULL) + +# else + +# define thread_in_use() 1 + +# endif + +/* -------------------------- gl_lock_t datatype -------------------------- */ + +typedef mutex_t gl_lock_t; +# define gl_lock_define(STORAGECLASS, NAME) \ + STORAGECLASS mutex_t NAME; +# define gl_lock_define_initialized(STORAGECLASS, NAME) \ + STORAGECLASS mutex_t NAME = gl_lock_initializer; +# define gl_lock_initializer \ + DEFAULTMUTEX +# define glthread_lock_init(LOCK) \ + (thread_in_use () ? mutex_init (LOCK, USYNC_THREAD, NULL) : 0) +# define glthread_lock_lock(LOCK) \ + (thread_in_use () ? mutex_lock (LOCK) : 0) +# define glthread_lock_unlock(LOCK) \ + (thread_in_use () ? mutex_unlock (LOCK) : 0) +# define glthread_lock_destroy(LOCK) \ + (thread_in_use () ? mutex_destroy (LOCK) : 0) + +/* ------------------------- gl_rwlock_t datatype ------------------------- */ + +typedef rwlock_t gl_rwlock_t; +# define gl_rwlock_define(STORAGECLASS, NAME) \ + STORAGECLASS rwlock_t NAME; +# define gl_rwlock_define_initialized(STORAGECLASS, NAME) \ + STORAGECLASS rwlock_t NAME = gl_rwlock_initializer; +# define gl_rwlock_initializer \ + DEFAULTRWLOCK +# define glthread_rwlock_init(LOCK) \ + (thread_in_use () ? rwlock_init (LOCK, USYNC_THREAD, NULL) : 0) +# define glthread_rwlock_rdlock(LOCK) \ + (thread_in_use () ? rw_rdlock (LOCK) : 0) +# define glthread_rwlock_wrlock(LOCK) \ + (thread_in_use () ? rw_wrlock (LOCK) : 0) +# define glthread_rwlock_unlock(LOCK) \ + (thread_in_use () ? rw_unlock (LOCK) : 0) +# define glthread_rwlock_destroy(LOCK) \ + (thread_in_use () ? rwlock_destroy (LOCK) : 0) + +/* --------------------- gl_recursive_lock_t datatype --------------------- */ + +/* Old Solaris threads did not have recursive locks. + We have to implement them ourselves. */ + +typedef struct + { + mutex_t mutex; + thread_t owner; + unsigned long depth; + } + gl_recursive_lock_t; +# define gl_recursive_lock_define(STORAGECLASS, NAME) \ + STORAGECLASS gl_recursive_lock_t NAME; +# define gl_recursive_lock_define_initialized(STORAGECLASS, NAME) \ + STORAGECLASS gl_recursive_lock_t NAME = gl_recursive_lock_initializer; +# define gl_recursive_lock_initializer \ + { DEFAULTMUTEX, (thread_t) 0, 0 } +# define glthread_recursive_lock_init(LOCK) \ + (thread_in_use () ? glthread_recursive_lock_init_multithreaded (LOCK) : 0) +# define glthread_recursive_lock_lock(LOCK) \ + (thread_in_use () ? glthread_recursive_lock_lock_multithreaded (LOCK) : 0) +# define glthread_recursive_lock_unlock(LOCK) \ + (thread_in_use () ? glthread_recursive_lock_unlock_multithreaded (LOCK) : 0) +# define glthread_recursive_lock_destroy(LOCK) \ + (thread_in_use () ? glthread_recursive_lock_destroy_multithreaded (LOCK) : 0) +extern int glthread_recursive_lock_init_multithreaded (gl_recursive_lock_t *lock); +extern int glthread_recursive_lock_lock_multithreaded (gl_recursive_lock_t *lock); +extern int glthread_recursive_lock_unlock_multithreaded (gl_recursive_lock_t *lock); +extern int glthread_recursive_lock_destroy_multithreaded (gl_recursive_lock_t *lock); + +/* -------------------------- gl_once_t datatype -------------------------- */ + +typedef struct + { + volatile int inited; + mutex_t mutex; + } + gl_once_t; +# define gl_once_define(STORAGECLASS, NAME) \ + STORAGECLASS gl_once_t NAME = { 0, DEFAULTMUTEX }; +# define glthread_once(ONCE_CONTROL, INITFUNCTION) \ + (thread_in_use () \ + ? glthread_once_multithreaded (ONCE_CONTROL, INITFUNCTION) \ + : (glthread_once_singlethreaded (ONCE_CONTROL) ? (INITFUNCTION (), 0) : 0)) +extern int glthread_once_multithreaded (gl_once_t *once_control, void (*initfunction) (void)); +extern int glthread_once_singlethreaded (gl_once_t *once_control); + +# ifdef __cplusplus +} +# endif + +#endif + +/* ========================================================================= */ + +#if USE_WIN32_THREADS + +# include <windows.h> + +# ifdef __cplusplus +extern "C" { +# endif + +/* We can use CRITICAL_SECTION directly, rather than the Win32 Event, Mutex, + Semaphore types, because + - we need only to synchronize inside a single process (address space), + not inter-process locking, + - we don't need to support trylock operations. (TryEnterCriticalSection + does not work on Windows 95/98/ME. Packages that need trylock usually + define their own mutex type.) */ + +/* There is no way to statically initialize a CRITICAL_SECTION. It needs + to be done lazily, once only. For this we need spinlocks. */ + +typedef struct { volatile int done; volatile long started; } gl_spinlock_t; + +/* -------------------------- gl_lock_t datatype -------------------------- */ + +typedef struct + { + gl_spinlock_t guard; /* protects the initialization */ + CRITICAL_SECTION lock; + } + gl_lock_t; +# define gl_lock_define(STORAGECLASS, NAME) \ + STORAGECLASS gl_lock_t NAME; +# define gl_lock_define_initialized(STORAGECLASS, NAME) \ + STORAGECLASS gl_lock_t NAME = gl_lock_initializer; +# define gl_lock_initializer \ + { { 0, -1 } } +# define glthread_lock_init(LOCK) \ + (glthread_lock_init_func (LOCK), 0) +# define glthread_lock_lock(LOCK) \ + glthread_lock_lock_func (LOCK) +# define glthread_lock_unlock(LOCK) \ + glthread_lock_unlock_func (LOCK) +# define glthread_lock_destroy(LOCK) \ + glthread_lock_destroy_func (LOCK) +extern void glthread_lock_init_func (gl_lock_t *lock); +extern int glthread_lock_lock_func (gl_lock_t *lock); +extern int glthread_lock_unlock_func (gl_lock_t *lock); +extern int glthread_lock_destroy_func (gl_lock_t *lock); + +/* ------------------------- gl_rwlock_t datatype ------------------------- */ + +/* It is impossible to implement read-write locks using plain locks, without + introducing an extra thread dedicated to managing read-write locks. + Therefore here we need to use the low-level Event type. */ + +typedef struct + { + HANDLE *array; /* array of waiting threads, each represented by an event */ + unsigned int count; /* number of waiting threads */ + unsigned int alloc; /* length of allocated array */ + unsigned int offset; /* index of first waiting thread in array */ + } + gl_carray_waitqueue_t; +typedef struct + { + gl_spinlock_t guard; /* protects the initialization */ + CRITICAL_SECTION lock; /* protects the remaining fields */ + gl_carray_waitqueue_t waiting_readers; /* waiting readers */ + gl_carray_waitqueue_t waiting_writers; /* waiting writers */ + int runcount; /* number of readers running, or -1 when a writer runs */ + } + gl_rwlock_t; +# define gl_rwlock_define(STORAGECLASS, NAME) \ + STORAGECLASS gl_rwlock_t NAME; +# define gl_rwlock_define_initialized(STORAGECLASS, NAME) \ + STORAGECLASS gl_rwlock_t NAME = gl_rwlock_initializer; +# define gl_rwlock_initializer \ + { { 0, -1 } } +# define glthread_rwlock_init(LOCK) \ + (glthread_rwlock_init_func (LOCK), 0) +# define glthread_rwlock_rdlock(LOCK) \ + glthread_rwlock_rdlock_func (LOCK) +# define glthread_rwlock_wrlock(LOCK) \ + glthread_rwlock_wrlock_func (LOCK) +# define glthread_rwlock_unlock(LOCK) \ + glthread_rwlock_unlock_func (LOCK) +# define glthread_rwlock_destroy(LOCK) \ + glthread_rwlock_destroy_func (LOCK) +extern void glthread_rwlock_init_func (gl_rwlock_t *lock); +extern int glthread_rwlock_rdlock_func (gl_rwlock_t *lock); +extern int glthread_rwlock_wrlock_func (gl_rwlock_t *lock); +extern int glthread_rwlock_unlock_func (gl_rwlock_t *lock); +extern int glthread_rwlock_destroy_func (gl_rwlock_t *lock); + +/* --------------------- gl_recursive_lock_t datatype --------------------- */ + +/* The Win32 documentation says that CRITICAL_SECTION already implements a + recursive lock. But we need not rely on it: It's easy to implement a + recursive lock without this assumption. */ + +typedef struct + { + gl_spinlock_t guard; /* protects the initialization */ + DWORD owner; + unsigned long depth; + CRITICAL_SECTION lock; + } + gl_recursive_lock_t; +# define gl_recursive_lock_define(STORAGECLASS, NAME) \ + STORAGECLASS gl_recursive_lock_t NAME; +# define gl_recursive_lock_define_initialized(STORAGECLASS, NAME) \ + STORAGECLASS gl_recursive_lock_t NAME = gl_recursive_lock_initializer; +# define gl_recursive_lock_initializer \ + { { 0, -1 }, 0, 0 } +# define glthread_recursive_lock_init(LOCK) \ + (glthread_recursive_lock_init_func (LOCK), 0) +# define glthread_recursive_lock_lock(LOCK) \ + glthread_recursive_lock_lock_func (LOCK) +# define glthread_recursive_lock_unlock(LOCK) \ + glthread_recursive_lock_unlock_func (LOCK) +# define glthread_recursive_lock_destroy(LOCK) \ + glthread_recursive_lock_destroy_func (LOCK) +extern void glthread_recursive_lock_init_func (gl_recursive_lock_t *lock); +extern int glthread_recursive_lock_lock_func (gl_recursive_lock_t *lock); +extern int glthread_recursive_lock_unlock_func (gl_recursive_lock_t *lock); +extern int glthread_recursive_lock_destroy_func (gl_recursive_lock_t *lock); + +/* -------------------------- gl_once_t datatype -------------------------- */ + +typedef struct + { + volatile int inited; + volatile long started; + CRITICAL_SECTION lock; + } + gl_once_t; +# define gl_once_define(STORAGECLASS, NAME) \ + STORAGECLASS gl_once_t NAME = { -1, -1 }; +# define glthread_once(ONCE_CONTROL, INITFUNCTION) \ + (glthread_once_func (ONCE_CONTROL, INITFUNCTION), 0) +extern void glthread_once_func (gl_once_t *once_control, void (*initfunction) (void)); + +# ifdef __cplusplus +} +# endif + +#endif + +/* ========================================================================= */ + +#if !(USE_POSIX_THREADS || USE_PTH_THREADS || USE_SOLARIS_THREADS || USE_WIN32_THREADS) + +/* Provide dummy implementation if threads are not supported. */ + +/* -------------------------- gl_lock_t datatype -------------------------- */ + +typedef int gl_lock_t; +# define gl_lock_define(STORAGECLASS, NAME) +# define gl_lock_define_initialized(STORAGECLASS, NAME) +# define glthread_lock_init(NAME) 0 +# define glthread_lock_lock(NAME) 0 +# define glthread_lock_unlock(NAME) 0 +# define glthread_lock_destroy(NAME) 0 + +/* ------------------------- gl_rwlock_t datatype ------------------------- */ + +typedef int gl_rwlock_t; +# define gl_rwlock_define(STORAGECLASS, NAME) +# define gl_rwlock_define_initialized(STORAGECLASS, NAME) +# define glthread_rwlock_init(NAME) 0 +# define glthread_rwlock_rdlock(NAME) 0 +# define glthread_rwlock_wrlock(NAME) 0 +# define glthread_rwlock_unlock(NAME) 0 +# define glthread_rwlock_destroy(NAME) 0 + +/* --------------------- gl_recursive_lock_t datatype --------------------- */ + +typedef int gl_recursive_lock_t; +# define gl_recursive_lock_define(STORAGECLASS, NAME) +# define gl_recursive_lock_define_initialized(STORAGECLASS, NAME) +# define glthread_recursive_lock_init(NAME) 0 +# define glthread_recursive_lock_lock(NAME) 0 +# define glthread_recursive_lock_unlock(NAME) 0 +# define glthread_recursive_lock_destroy(NAME) 0 + +/* -------------------------- gl_once_t datatype -------------------------- */ + +typedef int gl_once_t; +# define gl_once_define(STORAGECLASS, NAME) \ + STORAGECLASS gl_once_t NAME = 0; +# define glthread_once(ONCE_CONTROL, INITFUNCTION) \ + (*(ONCE_CONTROL) == 0 ? (*(ONCE_CONTROL) = ~ 0, INITFUNCTION (), 0) : 0) + +#endif + +/* ========================================================================= */ + +/* Macros with built-in error handling. */ + +/* -------------------------- gl_lock_t datatype -------------------------- */ + +#define gl_lock_init(NAME) \ + do \ + { \ + if (glthread_lock_init (&NAME)) \ + abort (); \ + } \ + while (0) +#define gl_lock_lock(NAME) \ + do \ + { \ + if (glthread_lock_lock (&NAME)) \ + abort (); \ + } \ + while (0) +#define gl_lock_unlock(NAME) \ + do \ + { \ + if (glthread_lock_unlock (&NAME)) \ + abort (); \ + } \ + while (0) +#define gl_lock_destroy(NAME) \ + do \ + { \ + if (glthread_lock_destroy (&NAME)) \ + abort (); \ + } \ + while (0) + +/* ------------------------- gl_rwlock_t datatype ------------------------- */ + +#define gl_rwlock_init(NAME) \ + do \ + { \ + if (glthread_rwlock_init (&NAME)) \ + abort (); \ + } \ + while (0) +#define gl_rwlock_rdlock(NAME) \ + do \ + { \ + if (glthread_rwlock_rdlock (&NAME)) \ + abort (); \ + } \ + while (0) +#define gl_rwlock_wrlock(NAME) \ + do \ + { \ + if (glthread_rwlock_wrlock (&NAME)) \ + abort (); \ + } \ + while (0) +#define gl_rwlock_unlock(NAME) \ + do \ + { \ + if (glthread_rwlock_unlock (&NAME)) \ + abort (); \ + } \ + while (0) +#define gl_rwlock_destroy(NAME) \ + do \ + { \ + if (glthread_rwlock_destroy (&NAME)) \ + abort (); \ + } \ + while (0) + +/* --------------------- gl_recursive_lock_t datatype --------------------- */ + +#define gl_recursive_lock_init(NAME) \ + do \ + { \ + if (glthread_recursive_lock_init (&NAME)) \ + abort (); \ + } \ + while (0) +#define gl_recursive_lock_lock(NAME) \ + do \ + { \ + if (glthread_recursive_lock_lock (&NAME)) \ + abort (); \ + } \ + while (0) +#define gl_recursive_lock_unlock(NAME) \ + do \ + { \ + if (glthread_recursive_lock_unlock (&NAME)) \ + abort (); \ + } \ + while (0) +#define gl_recursive_lock_destroy(NAME) \ + do \ + { \ + if (glthread_recursive_lock_destroy (&NAME)) \ + abort (); \ + } \ + while (0) + +/* -------------------------- gl_once_t datatype -------------------------- */ + +#define gl_once(NAME, INITFUNCTION) \ + do \ + { \ + if (glthread_once (&NAME, INITFUNCTION)) \ + abort (); \ + } \ + while (0) + +/* ========================================================================= */ + +#endif /* _LOCK_H */ diff --git a/lib/glthread/threadlib.c b/lib/glthread/threadlib.c new file mode 100644 index 00000000..8cb1bb21 --- /dev/null +++ b/lib/glthread/threadlib.c @@ -0,0 +1,74 @@ +/* Multithreading primitives. + Copyright (C) 2005-2010 Free Software Foundation, Inc. + + This program 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, or (at your option) + any later version. + + This program 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 this program; if not, write to the Free Software Foundation, + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + +/* Written by Bruno Haible <bruno@clisp.org>, 2005. */ + +#include <config.h> + +/* ========================================================================= */ + +#if USE_POSIX_THREADS + +/* Use the POSIX threads library. */ + +# include <pthread.h> +# include <stdlib.h> + +# if PTHREAD_IN_USE_DETECTION_HARD + +/* The function to be executed by a dummy thread. */ +static void * +dummy_thread_func (void *arg) +{ + return arg; +} + +int +glthread_in_use (void) +{ + static int tested; + static int result; /* 1: linked with -lpthread, 0: only with libc */ + + if (!tested) + { + pthread_t thread; + + if (pthread_create (&thread, NULL, dummy_thread_func, NULL) != 0) + /* Thread creation failed. */ + result = 0; + else + { + /* Thread creation works. */ + void *retval; + if (pthread_join (thread, &retval) != 0) + abort (); + result = 1; + } + tested = 1; + } + return result; +} + +# endif + +#endif + +/* ========================================================================= */ + +/* This declaration is solely to ensure that after preprocessing + this file is never empty. */ +typedef int dummy; |