michael@0: /*
michael@0:  * Copyright (c) 2008-2012 Niels Provos, Nick Mathewson
michael@0:  *
michael@0:  * Redistribution and use in source and binary forms, with or without
michael@0:  * modification, are permitted provided that the following conditions
michael@0:  * are met:
michael@0:  * 1. Redistributions of source code must retain the above copyright
michael@0:  *    notice, this list of conditions and the following disclaimer.
michael@0:  * 2. Redistributions in binary form must reproduce the above copyright
michael@0:  *    notice, this list of conditions and the following disclaimer in the
michael@0:  *    documentation and/or other materials provided with the distribution.
michael@0:  * 3. The name of the author may not be used to endorse or promote products
michael@0:  *    derived from this software without specific prior written permission.
michael@0:  *
michael@0:  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
michael@0:  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
michael@0:  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
michael@0:  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
michael@0:  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
michael@0:  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
michael@0:  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
michael@0:  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
michael@0:  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
michael@0:  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
michael@0:  */
michael@0: 
michael@0: #include "event2/event-config.h"
michael@0: 
michael@0: #ifndef _EVENT_DISABLE_THREAD_SUPPORT
michael@0: 
michael@0: #include "event2/thread.h"
michael@0: 
michael@0: #include <stdlib.h>
michael@0: #include <string.h>
michael@0: 
michael@0: #include "log-internal.h"
michael@0: #include "mm-internal.h"
michael@0: #include "util-internal.h"
michael@0: #include "evthread-internal.h"
michael@0: 
michael@0: #ifdef EVTHREAD_EXPOSE_STRUCTS
michael@0: #define GLOBAL
michael@0: #else
michael@0: #define GLOBAL static
michael@0: #endif
michael@0: 
michael@0: /* globals */
michael@0: GLOBAL int _evthread_lock_debugging_enabled = 0;
michael@0: GLOBAL struct evthread_lock_callbacks _evthread_lock_fns = {
michael@0: 	0, 0, NULL, NULL, NULL, NULL
michael@0: };
michael@0: GLOBAL unsigned long (*_evthread_id_fn)(void) = NULL;
michael@0: GLOBAL struct evthread_condition_callbacks _evthread_cond_fns = {
michael@0: 	0, NULL, NULL, NULL, NULL
michael@0: };
michael@0: 
michael@0: /* Used for debugging */
michael@0: static struct evthread_lock_callbacks _original_lock_fns = {
michael@0: 	0, 0, NULL, NULL, NULL, NULL
michael@0: };
michael@0: static struct evthread_condition_callbacks _original_cond_fns = {
michael@0: 	0, NULL, NULL, NULL, NULL
michael@0: };
michael@0: 
michael@0: void
michael@0: evthread_set_id_callback(unsigned long (*id_fn)(void))
michael@0: {
michael@0: 	_evthread_id_fn = id_fn;
michael@0: }
michael@0: 
michael@0: int
michael@0: evthread_set_lock_callbacks(const struct evthread_lock_callbacks *cbs)
michael@0: {
michael@0: 	struct evthread_lock_callbacks *target =
michael@0: 	    _evthread_lock_debugging_enabled
michael@0: 	    ? &_original_lock_fns : &_evthread_lock_fns;
michael@0: 
michael@0: 	if (!cbs) {
michael@0: 		if (target->alloc)
michael@0: 			event_warnx("Trying to disable lock functions after "
michael@0: 			    "they have been set up will probaby not work.");
michael@0: 		memset(target, 0, sizeof(_evthread_lock_fns));
michael@0: 		return 0;
michael@0: 	}
michael@0: 	if (target->alloc) {
michael@0: 		/* Uh oh; we already had locking callbacks set up.*/
michael@0: 		if (target->lock_api_version == cbs->lock_api_version &&
michael@0: 			target->supported_locktypes == cbs->supported_locktypes &&
michael@0: 			target->alloc == cbs->alloc &&
michael@0: 			target->free == cbs->free &&
michael@0: 			target->lock == cbs->lock &&
michael@0: 			target->unlock == cbs->unlock) {
michael@0: 			/* no change -- allow this. */
michael@0: 			return 0;
michael@0: 		}
michael@0: 		event_warnx("Can't change lock callbacks once they have been "
michael@0: 		    "initialized.");
michael@0: 		return -1;
michael@0: 	}
michael@0: 	if (cbs->alloc && cbs->free && cbs->lock && cbs->unlock) {
michael@0: 		memcpy(target, cbs, sizeof(_evthread_lock_fns));
michael@0: 		return event_global_setup_locks_(1);
michael@0: 	} else {
michael@0: 		return -1;
michael@0: 	}
michael@0: }
michael@0: 
michael@0: int
michael@0: evthread_set_condition_callbacks(const struct evthread_condition_callbacks *cbs)
michael@0: {
michael@0: 	struct evthread_condition_callbacks *target =
michael@0: 	    _evthread_lock_debugging_enabled
michael@0: 	    ? &_original_cond_fns : &_evthread_cond_fns;
michael@0: 
michael@0: 	if (!cbs) {
michael@0: 		if (target->alloc_condition)
michael@0: 			event_warnx("Trying to disable condition functions "
michael@0: 			    "after they have been set up will probaby not "
michael@0: 			    "work.");
michael@0: 		memset(target, 0, sizeof(_evthread_cond_fns));
michael@0: 		return 0;
michael@0: 	}
michael@0: 	if (target->alloc_condition) {
michael@0: 		/* Uh oh; we already had condition callbacks set up.*/
michael@0: 		if (target->condition_api_version == cbs->condition_api_version &&
michael@0: 			target->alloc_condition == cbs->alloc_condition &&
michael@0: 			target->free_condition == cbs->free_condition &&
michael@0: 			target->signal_condition == cbs->signal_condition &&
michael@0: 			target->wait_condition == cbs->wait_condition) {
michael@0: 			/* no change -- allow this. */
michael@0: 			return 0;
michael@0: 		}
michael@0: 		event_warnx("Can't change condition callbacks once they "
michael@0: 		    "have been initialized.");
michael@0: 		return -1;
michael@0: 	}
michael@0: 	if (cbs->alloc_condition && cbs->free_condition &&
michael@0: 	    cbs->signal_condition && cbs->wait_condition) {
michael@0: 		memcpy(target, cbs, sizeof(_evthread_cond_fns));
michael@0: 	}
michael@0: 	if (_evthread_lock_debugging_enabled) {
michael@0: 		_evthread_cond_fns.alloc_condition = cbs->alloc_condition;
michael@0: 		_evthread_cond_fns.free_condition = cbs->free_condition;
michael@0: 		_evthread_cond_fns.signal_condition = cbs->signal_condition;
michael@0: 	}
michael@0: 	return 0;
michael@0: }
michael@0: 
michael@0: struct debug_lock {
michael@0: 	unsigned locktype;
michael@0: 	unsigned long held_by;
michael@0: 	/* XXXX if we ever use read-write locks, we will need a separate
michael@0: 	 * lock to protect count. */
michael@0: 	int count;
michael@0: 	void *lock;
michael@0: };
michael@0: 
michael@0: static void *
michael@0: debug_lock_alloc(unsigned locktype)
michael@0: {
michael@0: 	struct debug_lock *result = mm_malloc(sizeof(struct debug_lock));
michael@0: 	if (!result)
michael@0: 		return NULL;
michael@0: 	if (_original_lock_fns.alloc) {
michael@0: 		if (!(result->lock = _original_lock_fns.alloc(
michael@0: 				locktype|EVTHREAD_LOCKTYPE_RECURSIVE))) {
michael@0: 			mm_free(result);
michael@0: 			return NULL;
michael@0: 		}
michael@0: 	} else {
michael@0: 		result->lock = NULL;
michael@0: 	}
michael@0: 	result->locktype = locktype;
michael@0: 	result->count = 0;
michael@0: 	result->held_by = 0;
michael@0: 	return result;
michael@0: }
michael@0: 
michael@0: static void
michael@0: debug_lock_free(void *lock_, unsigned locktype)
michael@0: {
michael@0: 	struct debug_lock *lock = lock_;
michael@0: 	EVUTIL_ASSERT(lock->count == 0);
michael@0: 	EVUTIL_ASSERT(locktype == lock->locktype);
michael@0: 	if (_original_lock_fns.free) {
michael@0: 		_original_lock_fns.free(lock->lock,
michael@0: 		    lock->locktype|EVTHREAD_LOCKTYPE_RECURSIVE);
michael@0: 	}
michael@0: 	lock->lock = NULL;
michael@0: 	lock->count = -100;
michael@0: 	mm_free(lock);
michael@0: }
michael@0: 
michael@0: static void
michael@0: evthread_debug_lock_mark_locked(unsigned mode, struct debug_lock *lock)
michael@0: {
michael@0: 	++lock->count;
michael@0: 	if (!(lock->locktype & EVTHREAD_LOCKTYPE_RECURSIVE))
michael@0: 		EVUTIL_ASSERT(lock->count == 1);
michael@0: 	if (_evthread_id_fn) {
michael@0: 		unsigned long me;
michael@0: 		me = _evthread_id_fn();
michael@0: 		if (lock->count > 1)
michael@0: 			EVUTIL_ASSERT(lock->held_by == me);
michael@0: 		lock->held_by = me;
michael@0: 	}
michael@0: }
michael@0: 
michael@0: static int
michael@0: debug_lock_lock(unsigned mode, void *lock_)
michael@0: {
michael@0: 	struct debug_lock *lock = lock_;
michael@0: 	int res = 0;
michael@0: 	if (lock->locktype & EVTHREAD_LOCKTYPE_READWRITE)
michael@0: 		EVUTIL_ASSERT(mode & (EVTHREAD_READ|EVTHREAD_WRITE));
michael@0: 	else
michael@0: 		EVUTIL_ASSERT((mode & (EVTHREAD_READ|EVTHREAD_WRITE)) == 0);
michael@0: 	if (_original_lock_fns.lock)
michael@0: 		res = _original_lock_fns.lock(mode, lock->lock);
michael@0: 	if (!res) {
michael@0: 		evthread_debug_lock_mark_locked(mode, lock);
michael@0: 	}
michael@0: 	return res;
michael@0: }
michael@0: 
michael@0: static void
michael@0: evthread_debug_lock_mark_unlocked(unsigned mode, struct debug_lock *lock)
michael@0: {
michael@0: 	if (lock->locktype & EVTHREAD_LOCKTYPE_READWRITE)
michael@0: 		EVUTIL_ASSERT(mode & (EVTHREAD_READ|EVTHREAD_WRITE));
michael@0: 	else
michael@0: 		EVUTIL_ASSERT((mode & (EVTHREAD_READ|EVTHREAD_WRITE)) == 0);
michael@0: 	if (_evthread_id_fn) {
michael@0: 		EVUTIL_ASSERT(lock->held_by == _evthread_id_fn());
michael@0: 		if (lock->count == 1)
michael@0: 			lock->held_by = 0;
michael@0: 	}
michael@0: 	--lock->count;
michael@0: 	EVUTIL_ASSERT(lock->count >= 0);
michael@0: }
michael@0: 
michael@0: static int
michael@0: debug_lock_unlock(unsigned mode, void *lock_)
michael@0: {
michael@0: 	struct debug_lock *lock = lock_;
michael@0: 	int res = 0;
michael@0: 	evthread_debug_lock_mark_unlocked(mode, lock);
michael@0: 	if (_original_lock_fns.unlock)
michael@0: 		res = _original_lock_fns.unlock(mode, lock->lock);
michael@0: 	return res;
michael@0: }
michael@0: 
michael@0: static int
michael@0: debug_cond_wait(void *_cond, void *_lock, const struct timeval *tv)
michael@0: {
michael@0: 	int r;
michael@0: 	struct debug_lock *lock = _lock;
michael@0: 	EVUTIL_ASSERT(lock);
michael@0: 	EVLOCK_ASSERT_LOCKED(_lock);
michael@0: 	evthread_debug_lock_mark_unlocked(0, lock);
michael@0: 	r = _original_cond_fns.wait_condition(_cond, lock->lock, tv);
michael@0: 	evthread_debug_lock_mark_locked(0, lock);
michael@0: 	return r;
michael@0: }
michael@0: 
michael@0: void
michael@0: evthread_enable_lock_debuging(void)
michael@0: {
michael@0: 	struct evthread_lock_callbacks cbs = {
michael@0: 		EVTHREAD_LOCK_API_VERSION,
michael@0: 		EVTHREAD_LOCKTYPE_RECURSIVE,
michael@0: 		debug_lock_alloc,
michael@0: 		debug_lock_free,
michael@0: 		debug_lock_lock,
michael@0: 		debug_lock_unlock
michael@0: 	};
michael@0: 	if (_evthread_lock_debugging_enabled)
michael@0: 		return;
michael@0: 	memcpy(&_original_lock_fns, &_evthread_lock_fns,
michael@0: 	    sizeof(struct evthread_lock_callbacks));
michael@0: 	memcpy(&_evthread_lock_fns, &cbs,
michael@0: 	    sizeof(struct evthread_lock_callbacks));
michael@0: 
michael@0: 	memcpy(&_original_cond_fns, &_evthread_cond_fns,
michael@0: 	    sizeof(struct evthread_condition_callbacks));
michael@0: 	_evthread_cond_fns.wait_condition = debug_cond_wait;
michael@0: 	_evthread_lock_debugging_enabled = 1;
michael@0: 
michael@0: 	/* XXX return value should get checked. */
michael@0: 	event_global_setup_locks_(0);
michael@0: }
michael@0: 
michael@0: int
michael@0: _evthread_is_debug_lock_held(void *lock_)
michael@0: {
michael@0: 	struct debug_lock *lock = lock_;
michael@0: 	if (! lock->count)
michael@0: 		return 0;
michael@0: 	if (_evthread_id_fn) {
michael@0: 		unsigned long me = _evthread_id_fn();
michael@0: 		if (lock->held_by != me)
michael@0: 			return 0;
michael@0: 	}
michael@0: 	return 1;
michael@0: }
michael@0: 
michael@0: void *
michael@0: _evthread_debug_get_real_lock(void *lock_)
michael@0: {
michael@0: 	struct debug_lock *lock = lock_;
michael@0: 	return lock->lock;
michael@0: }
michael@0: 
michael@0: void *
michael@0: evthread_setup_global_lock_(void *lock_, unsigned locktype, int enable_locks)
michael@0: {
michael@0: 	/* there are four cases here:
michael@0: 	   1) we're turning on debugging; locking is not on.
michael@0: 	   2) we're turning on debugging; locking is on.
michael@0: 	   3) we're turning on locking; debugging is not on.
michael@0: 	   4) we're turning on locking; debugging is on. */
michael@0: 
michael@0: 	if (!enable_locks && _original_lock_fns.alloc == NULL) {
michael@0: 		/* Case 1: allocate a debug lock. */
michael@0: 		EVUTIL_ASSERT(lock_ == NULL);
michael@0: 		return debug_lock_alloc(locktype);
michael@0: 	} else if (!enable_locks && _original_lock_fns.alloc != NULL) {
michael@0: 		/* Case 2: wrap the lock in a debug lock. */
michael@0: 		struct debug_lock *lock;
michael@0: 		EVUTIL_ASSERT(lock_ != NULL);
michael@0: 
michael@0: 		if (!(locktype & EVTHREAD_LOCKTYPE_RECURSIVE)) {
michael@0: 			/* We can't wrap it: We need a recursive lock */
michael@0: 			_original_lock_fns.free(lock_, locktype);
michael@0: 			return debug_lock_alloc(locktype);
michael@0: 		}
michael@0: 		lock = mm_malloc(sizeof(struct debug_lock));
michael@0: 		if (!lock) {
michael@0: 			_original_lock_fns.free(lock_, locktype);
michael@0: 			return NULL;
michael@0: 		}
michael@0: 		lock->lock = lock_;
michael@0: 		lock->locktype = locktype;
michael@0: 		lock->count = 0;
michael@0: 		lock->held_by = 0;
michael@0: 		return lock;
michael@0: 	} else if (enable_locks && ! _evthread_lock_debugging_enabled) {
michael@0: 		/* Case 3: allocate a regular lock */
michael@0: 		EVUTIL_ASSERT(lock_ == NULL);
michael@0: 		return _evthread_lock_fns.alloc(locktype);
michael@0: 	} else {
michael@0: 		/* Case 4: Fill in a debug lock with a real lock */
michael@0: 		struct debug_lock *lock = lock_;
michael@0: 		EVUTIL_ASSERT(enable_locks &&
michael@0: 		              _evthread_lock_debugging_enabled);
michael@0: 		EVUTIL_ASSERT(lock->locktype == locktype);
michael@0: 		EVUTIL_ASSERT(lock->lock == NULL);
michael@0: 		lock->lock = _original_lock_fns.alloc(
michael@0: 			locktype|EVTHREAD_LOCKTYPE_RECURSIVE);
michael@0: 		if (!lock->lock) {
michael@0: 			lock->count = -200;
michael@0: 			mm_free(lock);
michael@0: 			return NULL;
michael@0: 		}
michael@0: 		return lock;
michael@0: 	}
michael@0: }
michael@0: 
michael@0: 
michael@0: #ifndef EVTHREAD_EXPOSE_STRUCTS
michael@0: unsigned long
michael@0: _evthreadimpl_get_id()
michael@0: {
michael@0: 	return _evthread_id_fn ? _evthread_id_fn() : 1;
michael@0: }
michael@0: void *
michael@0: _evthreadimpl_lock_alloc(unsigned locktype)
michael@0: {
michael@0: 	return _evthread_lock_fns.alloc ?
michael@0: 	    _evthread_lock_fns.alloc(locktype) : NULL;
michael@0: }
michael@0: void
michael@0: _evthreadimpl_lock_free(void *lock, unsigned locktype)
michael@0: {
michael@0: 	if (_evthread_lock_fns.free)
michael@0: 		_evthread_lock_fns.free(lock, locktype);
michael@0: }
michael@0: int
michael@0: _evthreadimpl_lock_lock(unsigned mode, void *lock)
michael@0: {
michael@0: 	if (_evthread_lock_fns.lock)
michael@0: 		return _evthread_lock_fns.lock(mode, lock);
michael@0: 	else
michael@0: 		return 0;
michael@0: }
michael@0: int
michael@0: _evthreadimpl_lock_unlock(unsigned mode, void *lock)
michael@0: {
michael@0: 	if (_evthread_lock_fns.unlock)
michael@0: 		return _evthread_lock_fns.unlock(mode, lock);
michael@0: 	else
michael@0: 		return 0;
michael@0: }
michael@0: void *
michael@0: _evthreadimpl_cond_alloc(unsigned condtype)
michael@0: {
michael@0: 	return _evthread_cond_fns.alloc_condition ?
michael@0: 	    _evthread_cond_fns.alloc_condition(condtype) : NULL;
michael@0: }
michael@0: void
michael@0: _evthreadimpl_cond_free(void *cond)
michael@0: {
michael@0: 	if (_evthread_cond_fns.free_condition)
michael@0: 		_evthread_cond_fns.free_condition(cond);
michael@0: }
michael@0: int
michael@0: _evthreadimpl_cond_signal(void *cond, int broadcast)
michael@0: {
michael@0: 	if (_evthread_cond_fns.signal_condition)
michael@0: 		return _evthread_cond_fns.signal_condition(cond, broadcast);
michael@0: 	else
michael@0: 		return 0;
michael@0: }
michael@0: int
michael@0: _evthreadimpl_cond_wait(void *cond, void *lock, const struct timeval *tv)
michael@0: {
michael@0: 	if (_evthread_cond_fns.wait_condition)
michael@0: 		return _evthread_cond_fns.wait_condition(cond, lock, tv);
michael@0: 	else
michael@0: 		return 0;
michael@0: }
michael@0: int
michael@0: _evthreadimpl_is_lock_debugging_enabled(void)
michael@0: {
michael@0: 	return _evthread_lock_debugging_enabled;
michael@0: }
michael@0: 
michael@0: int
michael@0: _evthreadimpl_locking_enabled(void)
michael@0: {
michael@0: 	return _evthread_lock_fns.lock != NULL;
michael@0: }
michael@0: #endif
michael@0: 
michael@0: #endif