The Tor Browser: ipc/chromium/src/third_party/libevent/evthread.c@6474c204b198 (annotated)

ipc/chromium/src/third_party/libevent/evthread.c@6474c204b198 (annotated)

ipc/chromium/src/third_party/libevent/evthread.c

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

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

The Tor Browser / annotate

ipc/chromium/src/third_party/libevent/evthread.c@6474c204b198 (annotated)

ipc/chromium/src/third_party/libevent/evthread.c