2 * mutexes.c: Mutex handles
5 * Dick Porter (dick@ximian.com)
7 * (C) 2002-2006 Ximian, Inc.
16 #include <mono/io-layer/wapi.h>
17 #include <mono/io-layer/wapi-private.h>
18 #include <mono/io-layer/misc-private.h>
19 #include <mono/io-layer/handles-private.h>
20 #include <mono/io-layer/mono-mutex.h>
21 #include <mono/io-layer/mutex-private.h>
25 static void mutex_signal(gpointer handle);
26 static gboolean mutex_own (gpointer handle);
27 static gboolean mutex_is_owned (gpointer handle);
29 static void namedmutex_signal (gpointer handle);
30 static gboolean namedmutex_own (gpointer handle);
31 static gboolean namedmutex_is_owned (gpointer handle);
32 static void namedmutex_prewait (gpointer handle);
34 struct _WapiHandleOps _wapi_mutex_ops = {
36 mutex_signal, /* signal */
38 mutex_is_owned, /* is_owned */
39 NULL, /* special_wait */
43 void _wapi_mutex_details (gpointer handle_info)
45 struct _WapiHandle_mutex *mut = (struct _WapiHandle_mutex *)handle_info;
47 #ifdef PTHREAD_POINTER_ID
48 g_print ("own: %5d:%5p, count: %5u", mut->pid, mut->tid,
51 g_print ("own: %5d:%5ld, count: %5u", mut->pid, mut->tid,
56 struct _WapiHandleOps _wapi_namedmutex_ops = {
58 namedmutex_signal, /* signal */
59 namedmutex_own, /* own */
60 namedmutex_is_owned, /* is_owned */
61 NULL, /* special_wait */
62 namedmutex_prewait /* prewait */
65 static gboolean mutex_release (gpointer handle);
66 static gboolean namedmutex_release (gpointer handle);
70 gboolean (*release)(gpointer handle);
71 } mutex_ops[WAPI_HANDLE_COUNT] = {
86 static mono_once_t mutex_ops_once=MONO_ONCE_INIT;
88 static void mutex_ops_init (void)
90 _wapi_handle_register_capabilities (WAPI_HANDLE_MUTEX,
91 WAPI_HANDLE_CAP_WAIT |
92 WAPI_HANDLE_CAP_SIGNAL |
94 _wapi_handle_register_capabilities (WAPI_HANDLE_NAMEDMUTEX,
95 WAPI_HANDLE_CAP_WAIT |
96 WAPI_HANDLE_CAP_SIGNAL |
100 static void mutex_signal(gpointer handle)
102 ReleaseMutex(handle);
105 static gboolean mutex_own (gpointer handle)
107 struct _WapiHandle_mutex *mutex_handle;
110 ok = _wapi_lookup_handle (handle, WAPI_HANDLE_MUTEX,
111 (gpointer *)&mutex_handle);
113 g_warning ("%s: error looking up mutex handle %p", __func__,
118 _wapi_thread_own_mutex (handle);
121 g_message("%s: owning mutex handle %p", __func__, handle);
124 _wapi_handle_set_signal_state (handle, FALSE, FALSE);
126 mutex_handle->pid = _wapi_getpid ();
127 mutex_handle->tid = pthread_self ();
128 mutex_handle->recursion++;
131 g_message ("%s: mutex handle %p locked %d times by %d:%ld", __func__,
132 handle, mutex_handle->recursion, mutex_handle->pid,
139 static gboolean mutex_is_owned (gpointer handle)
141 struct _WapiHandle_mutex *mutex_handle;
144 ok=_wapi_lookup_handle (handle, WAPI_HANDLE_MUTEX,
145 (gpointer *)&mutex_handle);
147 g_warning ("%s: error looking up mutex handle %p", __func__,
153 g_message("%s: testing ownership mutex handle %p", __func__, handle);
156 if (mutex_handle->recursion > 0 &&
157 mutex_handle->pid == _wapi_getpid () &&
158 pthread_equal (mutex_handle->tid, pthread_self ())) {
160 g_message ("%s: mutex handle %p owned by %d:%ld", __func__,
161 handle, _wapi_getpid (), pthread_self ());
167 g_message ("%s: mutex handle %p not owned by %d:%ld, but locked %d times by %d:%ld", __func__, handle, _wapi_getpid (), pthread_self (), mutex_handle->recursion, mutex_handle->pid, mutex_handle->tid);
174 static void namedmutex_signal (gpointer handle)
176 ReleaseMutex(handle);
179 /* NB, always called with the shared handle lock held */
180 static gboolean namedmutex_own (gpointer handle)
182 struct _WapiHandle_namedmutex *namedmutex_handle;
186 g_message ("%s: owning named mutex handle %p", __func__, handle);
189 ok = _wapi_lookup_handle (handle, WAPI_HANDLE_NAMEDMUTEX,
190 (gpointer *)&namedmutex_handle);
192 g_warning ("%s: error looking up named mutex handle %p",
197 _wapi_thread_own_mutex (handle);
199 namedmutex_handle->pid = _wapi_getpid ();
200 namedmutex_handle->tid = pthread_self ();
201 namedmutex_handle->recursion++;
203 _wapi_shared_handle_set_signal_state (handle, FALSE);
206 g_message ("%s: mutex handle %p locked %d times by %d:%ld", __func__,
207 handle, namedmutex_handle->recursion,
208 namedmutex_handle->pid, namedmutex_handle->tid);
214 static gboolean namedmutex_is_owned (gpointer handle)
216 struct _WapiHandle_namedmutex *namedmutex_handle;
219 ok = _wapi_lookup_handle (handle, WAPI_HANDLE_NAMEDMUTEX,
220 (gpointer *)&namedmutex_handle);
222 g_warning ("%s: error looking up mutex handle %p", __func__,
228 g_message ("%s: testing ownership mutex handle %p", __func__, handle);
231 if (namedmutex_handle->recursion > 0 &&
232 namedmutex_handle->pid == _wapi_getpid () &&
233 pthread_equal (namedmutex_handle->tid, pthread_self ())) {
235 g_message ("%s: mutex handle %p owned by %d:%ld", __func__,
236 handle, _wapi_getpid (), pthread_self ());
242 g_message ("%s: mutex handle %p not owned by %d:%ld, but locked %d times by %d:%ld", __func__, handle, _wapi_getpid (), pthread_self (), namedmutex_handle->recursion, namedmutex_handle->pid, namedmutex_handle->tid);
249 /* The shared state is not locked when prewait methods are called */
250 static void namedmutex_prewait (gpointer handle)
252 /* If the mutex is not currently owned, do nothing and let the
253 * usual wait carry on. If it is owned, check that the owner
254 * is still alive; if it isn't we override the previous owner
255 * and assume that process exited abnormally and failed to
258 struct _WapiHandle_namedmutex *namedmutex_handle;
261 ok = _wapi_lookup_handle (handle, WAPI_HANDLE_NAMEDMUTEX,
262 (gpointer *)&namedmutex_handle);
264 g_warning ("%s: error looking up named mutex handle %p",
270 g_message ("%s: Checking ownership of named mutex handle %p", __func__,
274 if (namedmutex_handle->recursion == 0) {
276 g_message ("%s: Named mutex handle %p not owned", __func__,
279 } else if (namedmutex_handle->pid == _wapi_getpid ()) {
281 g_message ("%s: Named mutex handle %p owned by this process",
286 gpointer proc_handle;
289 g_message ("%s: Named mutex handle %p owned by another process", __func__, handle);
291 proc_handle = OpenProcess (0, 0, namedmutex_handle->pid);
292 if (proc_handle == NULL) {
293 /* Didn't find the process that this handle
294 * was owned by, overriding it
297 g_message ("%s: overriding old owner of named mutex handle %p", __func__, handle);
299 thr_ret = _wapi_handle_lock_shared_handles ();
300 g_assert (thr_ret == 0);
302 namedmutex_handle->pid = 0;
303 namedmutex_handle->tid = 0;
304 namedmutex_handle->recursion = 0;
306 _wapi_shared_handle_set_signal_state (handle, TRUE);
307 _wapi_handle_unlock_shared_handles ();
310 g_message ("%s: Found active pid %d for named mutex handle %p", __func__, namedmutex_handle->pid, handle);
313 if (proc_handle != NULL)
314 CloseProcess (proc_handle);
318 static void mutex_abandon (gpointer handle, pid_t pid, pthread_t tid)
320 struct _WapiHandle_mutex *mutex_handle;
324 ok = _wapi_lookup_handle (handle, WAPI_HANDLE_MUTEX,
325 (gpointer *)&mutex_handle);
327 g_warning ("%s: error looking up mutex handle %p", __func__,
332 pthread_cleanup_push ((void(*)(void *))_wapi_handle_unlock_handle,
334 thr_ret = _wapi_handle_lock_handle (handle);
335 g_assert (thr_ret == 0);
337 if (mutex_handle->pid == pid &&
338 pthread_equal (mutex_handle->tid, tid)) {
340 g_message ("%s: Mutex handle %p abandoned!", __func__, handle);
343 mutex_handle->recursion = 0;
344 mutex_handle->pid = 0;
345 mutex_handle->tid = 0;
347 _wapi_handle_set_signal_state (handle, TRUE, FALSE);
350 thr_ret = _wapi_handle_unlock_handle (handle);
351 g_assert (thr_ret == 0);
352 pthread_cleanup_pop (0);
355 static void namedmutex_abandon (gpointer handle, pid_t pid, pthread_t tid)
357 struct _WapiHandle_namedmutex *mutex_handle;
361 ok = _wapi_lookup_handle (handle, WAPI_HANDLE_NAMEDMUTEX,
362 (gpointer *)&mutex_handle);
364 g_warning ("%s: error looking up named mutex handle %p",
369 thr_ret = _wapi_handle_lock_shared_handles ();
370 g_assert (thr_ret == 0);
372 if (mutex_handle->pid == pid &&
373 pthread_equal (mutex_handle->tid, tid)) {
375 g_message ("%s: Mutex handle %p abandoned!", __func__, handle);
378 mutex_handle->recursion = 0;
379 mutex_handle->pid = 0;
380 mutex_handle->tid = 0;
382 _wapi_shared_handle_set_signal_state (handle, TRUE);
385 _wapi_handle_unlock_shared_handles ();
388 /* When a thread exits, any mutexes it still holds need to be
389 * signalled. This function must not be called with the shared handle
390 * lock held, as namedmutex_abandon () will try to acquire it
392 void _wapi_mutex_abandon (gpointer data, pid_t pid, pthread_t tid)
394 WapiHandleType type = _wapi_handle_type (data);
396 if (type == WAPI_HANDLE_MUTEX) {
397 mutex_abandon (data, pid, tid);
398 } else if (type == WAPI_HANDLE_NAMEDMUTEX) {
399 namedmutex_abandon (data, pid, tid);
401 g_assert_not_reached ();
405 static gpointer mutex_create (WapiSecurityAttributes *security G_GNUC_UNUSED,
408 struct _WapiHandle_mutex mutex_handle = {0};
412 /* Need to blow away any old errors here, because code tests
413 * for ERROR_ALREADY_EXISTS on success (!) to see if a mutex
414 * was freshly created
416 SetLastError (ERROR_SUCCESS);
419 g_message ("%s: Creating unnamed mutex", __func__);
422 handle = _wapi_handle_new (WAPI_HANDLE_MUTEX, &mutex_handle);
423 if (handle == _WAPI_HANDLE_INVALID) {
424 g_warning ("%s: error creating mutex handle", __func__);
425 SetLastError (ERROR_GEN_FAILURE);
429 pthread_cleanup_push ((void(*)(void *))_wapi_handle_unlock_handle,
431 thr_ret = _wapi_handle_lock_handle (handle);
432 g_assert (thr_ret == 0);
437 _wapi_handle_set_signal_state (handle, TRUE, FALSE);
441 g_message ("%s: returning mutex handle %p", __func__, handle);
444 thr_ret = _wapi_handle_unlock_handle (handle);
445 g_assert (thr_ret == 0);
446 pthread_cleanup_pop (0);
451 static gpointer namedmutex_create (WapiSecurityAttributes *security G_GNUC_UNUSED, gboolean owned,
452 const gunichar2 *name)
454 struct _WapiHandle_namedmutex namedmutex_handle = {{{0}}, 0};
462 /* w32 seems to guarantee that opening named objects can't
465 thr_ret = _wapi_namespace_lock ();
466 g_assert (thr_ret == 0);
468 /* Need to blow away any old errors here, because code tests
469 * for ERROR_ALREADY_EXISTS on success (!) to see if a mutex
470 * was freshly created
472 SetLastError (ERROR_SUCCESS);
474 utf8_name = g_utf16_to_utf8 (name, -1, NULL, NULL, NULL);
477 g_message ("%s: Creating named mutex [%s]", __func__, utf8_name);
480 offset = _wapi_search_handle_namespace (WAPI_HANDLE_NAMEDMUTEX,
483 /* The name has already been used for a different
486 SetLastError (ERROR_INVALID_HANDLE);
488 } else if (offset != 0) {
489 /* Not an error, but this is how the caller is
490 * informed that the mutex wasn't freshly created
492 SetLastError (ERROR_ALREADY_EXISTS);
494 /* Fall through to create the mutex handle. */
497 /* A new named mutex, so create both the private and
501 if (strlen (utf8_name) < MAX_PATH) {
502 namelen = strlen (utf8_name);
507 memcpy (&namedmutex_handle.sharedns.name, utf8_name, namelen);
509 handle = _wapi_handle_new (WAPI_HANDLE_NAMEDMUTEX,
512 /* A new reference to an existing named mutex, so just
513 * create the private part
515 handle = _wapi_handle_new_from_offset (WAPI_HANDLE_NAMEDMUTEX,
519 if (handle == _WAPI_HANDLE_INVALID) {
520 g_warning ("%s: error creating mutex handle", __func__);
521 SetLastError (ERROR_GEN_FAILURE);
527 /* Set the initial state, as this is a completely new
530 thr_ret = _wapi_handle_lock_shared_handles ();
531 g_assert (thr_ret == 0);
534 namedmutex_own (handle);
536 _wapi_shared_handle_set_signal_state (handle, TRUE);
539 _wapi_handle_unlock_shared_handles ();
543 g_message ("%s: returning mutex handle %p", __func__, handle);
549 _wapi_namespace_unlock (NULL);
556 * @security: Ignored for now.
557 * @owned: If %TRUE, the mutex is created with the calling thread
558 * already owning the mutex.
559 * @name:Pointer to a string specifying the name of this mutex, or
562 * Creates a new mutex handle. A mutex is signalled when no thread
563 * owns it. A thread acquires ownership of the mutex by waiting for
564 * it with WaitForSingleObject() or WaitForMultipleObjects(). A
565 * thread relinquishes ownership with ReleaseMutex().
567 * A thread that owns a mutex can specify the same mutex in repeated
568 * wait function calls without blocking. The thread must call
569 * ReleaseMutex() an equal number of times to release the mutex.
571 * Return value: A new handle, or %NULL on error.
573 gpointer CreateMutex(WapiSecurityAttributes *security G_GNUC_UNUSED, gboolean owned,
574 const gunichar2 *name)
576 mono_once (&mutex_ops_once, mutex_ops_init);
579 return(mutex_create (security, owned));
581 return(namedmutex_create (security, owned, name));
585 static gboolean mutex_release (gpointer handle)
587 struct _WapiHandle_mutex *mutex_handle;
589 pthread_t tid = pthread_self ();
590 pid_t pid = _wapi_getpid ();
592 gboolean ret = FALSE;
594 ok = _wapi_lookup_handle (handle, WAPI_HANDLE_MUTEX,
595 (gpointer *)&mutex_handle);
597 g_warning ("%s: error looking up mutex handle %p", __func__,
602 pthread_cleanup_push ((void(*)(void *))_wapi_handle_unlock_handle,
604 thr_ret = _wapi_handle_lock_handle (handle);
605 g_assert (thr_ret == 0);
608 g_message("%s: Releasing mutex handle %p", __func__, handle);
611 if (!pthread_equal (mutex_handle->tid, tid) ||
612 mutex_handle->pid != pid) {
614 g_message("%s: We don't own mutex handle %p (owned by %d:%ld, me %d:%ld)", __func__, handle, mutex_handle->pid, mutex_handle->tid, _wapi_getpid (), tid);
621 /* OK, we own this mutex */
622 mutex_handle->recursion--;
624 if(mutex_handle->recursion==0) {
625 _wapi_thread_disown_mutex (handle);
628 g_message("%s: Unlocking mutex handle %p", __func__, handle);
633 _wapi_handle_set_signal_state (handle, TRUE, FALSE);
637 thr_ret = _wapi_handle_unlock_handle (handle);
638 g_assert (thr_ret == 0);
639 pthread_cleanup_pop (0);
644 static gboolean namedmutex_release (gpointer handle)
646 struct _WapiHandle_namedmutex *mutex_handle;
648 pthread_t tid = pthread_self ();
649 pid_t pid = _wapi_getpid ();
651 gboolean ret = FALSE;
653 ok=_wapi_lookup_handle (handle, WAPI_HANDLE_NAMEDMUTEX,
654 (gpointer *)&mutex_handle);
656 g_warning ("%s: error looking up named mutex handle %p",
661 thr_ret = _wapi_handle_lock_shared_handles ();
662 g_assert (thr_ret == 0);
665 g_message("%s: Releasing mutex handle %p", __func__, handle);
668 if (!pthread_equal (mutex_handle->tid, tid) ||
669 mutex_handle->pid != pid) {
671 g_message("%s: We don't own mutex handle %p (owned by %d:%ld, me %d:%ld)", __func__, handle, mutex_handle->pid, mutex_handle->tid, _wapi_getpid (), tid);
678 /* OK, we own this mutex */
679 mutex_handle->recursion--;
681 if(mutex_handle->recursion==0) {
682 _wapi_thread_disown_mutex (handle);
685 g_message("%s: Unlocking mutex handle %p", __func__, handle);
690 _wapi_shared_handle_set_signal_state (handle, TRUE);
694 _wapi_handle_unlock_shared_handles ();
701 * @handle: The mutex handle.
703 * Releases ownership if the mutex handle @handle.
705 * Return value: %TRUE on success, %FALSE otherwise. This function
706 * fails if the calling thread does not own the mutex @handle.
708 gboolean ReleaseMutex(gpointer handle)
712 if (handle == NULL) {
713 SetLastError (ERROR_INVALID_HANDLE);
717 type = _wapi_handle_type (handle);
719 if (mutex_ops[type].release == NULL) {
720 SetLastError (ERROR_INVALID_HANDLE);
724 return(mutex_ops[type].release (handle));
727 gpointer OpenMutex (guint32 access G_GNUC_UNUSED, gboolean inherit G_GNUC_UNUSED, const gunichar2 *name)
735 mono_once (&mutex_ops_once, mutex_ops_init);
737 /* w32 seems to guarantee that opening named objects can't
740 thr_ret = _wapi_namespace_lock ();
741 g_assert (thr_ret == 0);
743 utf8_name = g_utf16_to_utf8 (name, -1, NULL, NULL, NULL);
746 g_message ("%s: Opening named mutex [%s]", __func__, utf8_name);
749 offset = _wapi_search_handle_namespace (WAPI_HANDLE_NAMEDMUTEX,
752 /* The name has already been used for a different
755 SetLastError (ERROR_INVALID_HANDLE);
757 } else if (offset == 0) {
758 /* This name doesn't exist */
759 SetLastError (ERROR_FILE_NOT_FOUND); /* yes, really */
763 /* A new reference to an existing named mutex, so just create
766 handle = _wapi_handle_new_from_offset (WAPI_HANDLE_NAMEDMUTEX, offset,
769 if (handle == _WAPI_HANDLE_INVALID) {
770 g_warning ("%s: error opening named mutex handle", __func__);
771 SetLastError (ERROR_GEN_FAILURE);
777 g_message ("%s: returning named mutex handle %p", __func__, handle);
783 _wapi_namespace_unlock (NULL);