| /* |
| * 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, 0, NULL, NULL, NULL, NULL |
| }; |
| GLOBAL unsigned long (*_evthread_id_fn)(void) = NULL; |
| GLOBAL struct evthread_condition_callbacks _evthread_cond_fns = { |
| 0, NULL, NULL, NULL, NULL |
| }; |
| |
| /* Used for debugging */ |
| static struct evthread_lock_callbacks _original_lock_fns = { |
| 0, 0, NULL, NULL, NULL, NULL |
| }; |
| static struct evthread_condition_callbacks _original_cond_fns = { |
| 0, 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: |
| 1) we're turning on debugging; locking is not on. |
| 2) we're turning on debugging; locking is on. |
| 3) we're turning on locking; debugging is not on. |
| 4) 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 |