]> git.saurik.com Git - apple/libc.git/blobdiff - pthreads/pthread_mutex.c
Libc-391.2.5.tar.gz
[apple/libc.git] / pthreads / pthread_mutex.c
index c82a6925eca564fdea1d98f117792151fa91ba57..1c8567064298c810f5b6f5cc748ce2aea481801a 100644 (file)
@@ -1,3 +1,25 @@
+/*
+ * Copyright (c) 2000-2003 Apple Computer, Inc. All rights reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ * 
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ * 
+ * @APPLE_LICENSE_HEADER_END@
+ */
 /*
  * Copyright 1996 1995 by Open Software Foundation, Inc. 1997 1996 1995 1994 1993 1992 1991
  *              All Rights Reserved
 int
 pthread_mutex_destroy(pthread_mutex_t *mutex)
 {
-        if (mutex->sig != _PTHREAD_MUTEX_SIG)
-                return (EINVAL);
-        if ((mutex->owner != (pthread_t)NULL) ||
-            (mutex->busy != (pthread_cond_t *)NULL))
-                return (EBUSY);
-        mutex->sig = _PTHREAD_NO_SIG;
+       int res;
+
+       LOCK(mutex->lock);
+       if (mutex->sig == _PTHREAD_MUTEX_SIG)
+       {
+               if (mutex->owner == (pthread_t)NULL &&
+                   mutex->busy == (pthread_cond_t *)NULL)
+               {
+                       mutex->sig = _PTHREAD_NO_SIG;
+                       res = ESUCCESS;
+               }
+               else
+                       res = EBUSY;
+       }
+       else
+               res = EINVAL;
+       UNLOCK(mutex->lock);
+       return (res);
+}
+
+/*
+ * Initialize a mutex variable, possibly with additional attributes.
+ */
+static int
+_pthread_mutex_init(pthread_mutex_t *mutex, const pthread_mutexattr_t *attr)
+{
+       if (attr)
+       {
+               if (attr->sig != _PTHREAD_MUTEX_ATTR_SIG)
+                       return (EINVAL);
+               mutex->prioceiling = attr->prioceiling;
+               mutex->protocol = attr->protocol;
+               mutex->type = attr->type;
+       } else {
+               mutex->prioceiling = _PTHREAD_DEFAULT_PRIOCEILING;
+               mutex->protocol = _PTHREAD_DEFAULT_PROTOCOL;
+               mutex->type = PTHREAD_MUTEX_DEFAULT;
+       }
+       mutex->lock_count = 0;
+       mutex->owner = (pthread_t)NULL;
+       mutex->next = (pthread_mutex_t *)NULL;
+       mutex->prev = (pthread_mutex_t *)NULL;
+       mutex->busy = (pthread_cond_t *)NULL;
+       mutex->waiters = 0;
+       mutex->sem = SEMAPHORE_NULL;
+       mutex->order = SEMAPHORE_NULL;
+       mutex->sig = _PTHREAD_MUTEX_SIG;
        return (ESUCCESS);
 }
 
 /*
  * Initialize a mutex variable, possibly with additional attributes.
+ * Public interface - so don't trust the lock - initialize it first.
  */
 int
 pthread_mutex_init(pthread_mutex_t *mutex, const pthread_mutexattr_t *attr)
 {
-        LOCK_INIT(mutex->lock);
-        mutex->sig = _PTHREAD_MUTEX_SIG;
-        if (attr)
-        {
-                if (attr->sig != _PTHREAD_MUTEX_ATTR_SIG)
-                        return (EINVAL);
-                mutex->prioceiling = attr->prioceiling;
-                mutex->protocol = attr->protocol;
-                mutex->type = attr->type;
-               if ((mutex->type == PTHREAD_MUTEX_DEFAULT) || (mutex->type == PTHREAD_MUTEX_NORMAL)) 
-                       mutex->def = 1;
-               else
-                       mutex->def = 0;
-        } else {
-                mutex->prioceiling = _PTHREAD_DEFAULT_PRIOCEILING;
-                mutex->protocol = _PTHREAD_DEFAULT_PROTOCOL;
-                mutex->type = PTHREAD_MUTEX_DEFAULT;
-               mutex->def = 1;
-        }
-        mutex->lock_count = 0;
-        mutex->owner = (pthread_t)NULL;
-        mutex->next = (pthread_mutex_t *)NULL;
-        mutex->prev = (pthread_mutex_t *)NULL;
-        mutex->busy = (pthread_cond_t *)NULL;
-       mutex->waiters = 0;
-       mutex->cond_lock = 0;
-       mutex->sem = MACH_PORT_NULL;
-       return (ESUCCESS);
+       LOCK_INIT(mutex->lock);
+       return (_pthread_mutex_init(mutex, attr));
 }
 
 /*
@@ -89,18 +127,19 @@ static void
 _pthread_mutex_add(pthread_mutex_t *mutex, pthread_t self)
 {
         pthread_mutex_t *m;
-        if (self != (pthread_t)0) {
-            if ((m = self->mutexes) != (pthread_mutex_t *)NULL)
+       if (self != (pthread_t)0)
+       {
+               if ((m = self->mutexes) != (pthread_mutex_t *)NULL)
                 { /* Add to list */
-                       m->prev = mutex;
+                       m->prev = mutex;
                 }
-            mutex->next = m;
-            mutex->prev = (pthread_mutex_t *)NULL;
-            self->mutexes = mutex;
+               mutex->next = m;
+               mutex->prev = (pthread_mutex_t *)NULL;
+               self->mutexes = mutex;
        }
 }
 
-static void
+__private_extern__ void
 _pthread_mutex_remove(pthread_mutex_t *mutex, pthread_t self)
 {
         pthread_mutex_t *n, *prev;
@@ -113,9 +152,9 @@ _pthread_mutex_remove(pthread_mutex_t *mutex, pthread_t self)
                 prev->next = mutex->next;
         } else
         { /* This is the first in the list */
-            if (self != (pthread_t)0) {
-                self->mutexes = n;
-            }
+               if (self != (pthread_t)0) {
+                       self->mutexes = n;
+               }
         }
 }
 #endif
@@ -127,74 +166,100 @@ _pthread_mutex_remove(pthread_mutex_t *mutex, pthread_t self)
 int
 pthread_mutex_lock(pthread_mutex_t *mutex)
 {
-        kern_return_t kern_res;
-        pthread_t self;
-       int slowpath;
-
-        if (mutex->sig == _PTHREAD_MUTEX_SIG_init)
-        {
-                int res;
-                if (res = pthread_mutex_init(mutex, NULL))
-                        return (res);
-        }
-        if (mutex->sig != _PTHREAD_MUTEX_SIG)
-                return (EINVAL);        /* Not a mutex variable */
-
-#if !defined(DEBUG)
-       if (mutex->def) {
-               slowpath = 0;
-               self = (pthread_t)0x12141968;
-       } else 
-#endif /* DEBUG */
+       kern_return_t kern_res;
+       pthread_t self;
+       int sig = mutex->sig; 
+
+       /* To provide backwards compat for apps using mutex incorrectly */
+       if ((sig != _PTHREAD_MUTEX_SIG) && (sig != _PTHREAD_MUTEX_SIG_init))
+               return(EINVAL);
+       LOCK(mutex->lock);
+       if (mutex->sig != _PTHREAD_MUTEX_SIG)
        {
-               slowpath = 1;
-               self = pthread_self();
-       }
-
-        LOCK(mutex->lock);
-                
-       if (mutex->waiters || (mutex->owner != (pthread_t)NULL))
+               if (mutex->sig != _PTHREAD_MUTEX_SIG_init)
+               {
+                       UNLOCK(mutex->lock);
+                       return (EINVAL);
+               }
+               _pthread_mutex_init(mutex, NULL);
+               self = _PTHREAD_MUTEX_OWNER_SELF;
+       } 
+       else if (mutex->type != PTHREAD_MUTEX_NORMAL)
        {
-               if(slowpath && (mutex->owner == self)) {
-                       if(mutex->type == PTHREAD_MUTEX_ERRORCHECK ) {
-                                       UNLOCK(mutex->lock);
-                                       return(EDEADLK);
-                       } else if (mutex->type == PTHREAD_MUTEX_RECURSIVE ) {
-                               if (mutex->lock_count >= USHRT_MAX){
-                                               UNLOCK(mutex->lock);
-                                       return(EAGAIN);
-                               }
-                               mutex->lock_count++;
-                                       UNLOCK(mutex->lock);
-                                       return(ESUCCESS);
-                       }
-               } 
-                mutex->waiters++;
-                if (mutex->sem == MACH_PORT_NULL) {
-                       mutex->sem = new_sem_from_pool();
+               self = pthread_self();
+               if (mutex->owner == self)
+               {
+                       int res;
+
+                       if (mutex->type == PTHREAD_MUTEX_RECURSIVE)
+                       {
+                               if (mutex->lock_count < USHRT_MAX)
+                               {
+                                       mutex->lock_count++;
+                                       res = ESUCCESS;
+                               } else
+                                       res = EAGAIN;
+                       } else  /* PTHREAD_MUTEX_ERRORCHECK */
+                               res = EDEADLK;
+                       UNLOCK(mutex->lock);
+                       return (res);
                }
-                UNLOCK(mutex->lock);
-               do {
-                       PTHREAD_MACH_CALL(semaphore_wait(mutex->sem), kern_res);
-               } while (kern_res == KERN_ABORTED);
-                LOCK(mutex->lock);
-               mutex->waiters--;
-               if (mutex->waiters == 0) {
-                       restore_sem_to_pool(mutex->sem);
-                       mutex->sem = MACH_PORT_NULL;
+       } else 
+               self = _PTHREAD_MUTEX_OWNER_SELF;
+
+       if (mutex->owner != (pthread_t)NULL) {
+               if (mutex->waiters || mutex->owner != _PTHREAD_MUTEX_OWNER_SWITCHING)
+               {
+                       semaphore_t sem, order;
+
+                       if (++mutex->waiters == 1)
+                       {
+                               mutex->sem = sem = new_sem_from_pool();
+                               mutex->order = order = new_sem_from_pool();
+                       }
+                       else
+                       {
+                               sem = mutex->sem;
+                               order = mutex->order;
+                               do {
+                                       PTHREAD_MACH_CALL(semaphore_wait(order), kern_res);
+                               } while (kern_res == KERN_ABORTED);
+                       } 
+                       UNLOCK(mutex->lock);
+
+                       PTHREAD_MACH_CALL(semaphore_wait_signal(sem, order), kern_res);
+                       while (kern_res == KERN_ABORTED)
+                       {
+                               PTHREAD_MACH_CALL(semaphore_wait(sem), kern_res);
+                       } 
+
+                       LOCK(mutex->lock);
+                       if (--mutex->waiters == 0)
+                       {
+                               PTHREAD_MACH_CALL(semaphore_wait(order), kern_res);
+                               mutex->sem = mutex->order = SEMAPHORE_NULL;
+                               restore_sem_to_pool(order);
+                               restore_sem_to_pool(sem);
+                       }
+               } 
+               else if (mutex->owner == _PTHREAD_MUTEX_OWNER_SWITCHING)
+               {
+                       semaphore_t sem = mutex->sem;
+                       do {
+                               PTHREAD_MACH_CALL(semaphore_wait(sem), kern_res);
+                       } while (kern_res == KERN_ABORTED);
+                       mutex->sem = SEMAPHORE_NULL;
+                       restore_sem_to_pool(sem);
                }
-                if (mutex->cond_lock) {
-                    mutex->cond_lock = 0;
-                }
-        }
-#if  defined(DEBUG) 
-        _pthread_mutex_add(mutex, self);
+       }
+
+       mutex->lock_count = 1;
+       mutex->owner = self;
+#if defined(DEBUG)
+       _pthread_mutex_add(mutex, self);
 #endif
-        mutex->owner = self;
-        if (slowpath && (mutex->type == PTHREAD_MUTEX_RECURSIVE))
-                mutex->lock_count = 1;
-        UNLOCK(mutex->lock);
-        return (ESUCCESS);
+       UNLOCK(mutex->lock);
+       return (ESUCCESS);
 }
 
 /*
@@ -203,65 +268,68 @@ pthread_mutex_lock(pthread_mutex_t *mutex)
 int
 pthread_mutex_trylock(pthread_mutex_t *mutex)
 {
-        kern_return_t kern_res;
-        pthread_t self;
-       int slowpath;
-       
-       if (mutex->sig == _PTHREAD_MUTEX_SIG_init)
-        {
-                int res;
-                if (res = pthread_mutex_init(mutex, NULL))
-                        return (res);
-        }
-        if (mutex->sig != _PTHREAD_MUTEX_SIG)
-                return (EINVAL);        /* Not a mutex variable */
-        
-#if !defined(DEBUG)
-       if (mutex->def) {
-               slowpath = 0;
-               self = (pthread_t)0x12141968;
-       } else 
-#endif /* DEBUG */
+       kern_return_t kern_res;
+       pthread_t self;
+
+       LOCK(mutex->lock);
+       if (mutex->sig != _PTHREAD_MUTEX_SIG)
        {
-               slowpath = 1;
-               self = pthread_self();
+               if (mutex->sig != _PTHREAD_MUTEX_SIG_init)
+               {
+                       UNLOCK(mutex->lock);
+                       return (EINVAL);
+               }
+               _pthread_mutex_init(mutex, NULL);
+               self = _PTHREAD_MUTEX_OWNER_SELF;
        }
+       else if (mutex->type != PTHREAD_MUTEX_NORMAL)
+       {
+               self = pthread_self();
+               if (mutex->type == PTHREAD_MUTEX_RECURSIVE)
+               {
+                       if (mutex->owner == self)
+                       {
+                               int res;
+
+                               if (mutex->lock_count < USHRT_MAX)
+                               {
+                                       mutex->lock_count++;
+                                       res = ESUCCESS;
+                               } else
+                                       res = EAGAIN;
+                               UNLOCK(mutex->lock);
+                               return (res);
+                       }
+               }
+       } else
+               self = _PTHREAD_MUTEX_OWNER_SELF;
 
-        if (!TRY_LOCK(mutex->lock)) {
-            return (EBUSY);
-        }
-
-        if(slowpath && (mutex->owner == self) && (mutex->type == PTHREAD_MUTEX_RECURSIVE )) {
-               if (mutex->lock_count >= USHRT_MAX) {
-                               UNLOCK(mutex->lock);
-                       return(EAGAIN);
+       if (mutex->owner != (pthread_t)NULL)
+       {
+               if (mutex->waiters || mutex->owner != _PTHREAD_MUTEX_OWNER_SWITCHING)
+               {
+                       UNLOCK(mutex->lock);
+                       return (EBUSY);
                }
-               mutex->lock_count++;
-               UNLOCK(mutex->lock);
-               return(ESUCCESS);
-        } 
-        
-        if (mutex->waiters ||
-               ((mutex->owner != (pthread_t)NULL) && (mutex->cond_lock == 0)))
-        {
-                UNLOCK(mutex->lock);
-                return (EBUSY);
-        } else {
+               else if (mutex->owner == _PTHREAD_MUTEX_OWNER_SWITCHING)
+               {
+                       semaphore_t sem = mutex->sem;
+
+                       do {
+                               PTHREAD_MACH_CALL(semaphore_wait(sem), kern_res);
+                       } while (kern_res == KERN_ABORTED);
+                       restore_sem_to_pool(sem);
+                       mutex->sem = SEMAPHORE_NULL;
+               }
+       }
+
+       mutex->lock_count = 1;
+       mutex->owner = self;
 #if defined(DEBUG)
-                _pthread_mutex_add(mutex, self);
+       _pthread_mutex_add(mutex, self);
 #endif
-                mutex->owner = (pthread_t)self;
-               if (mutex->cond_lock) {
-                    PTHREAD_MACH_CALL(semaphore_wait(mutex->sem), kern_res);
-                    mutex->cond_lock = 0;
-                    restore_sem_to_pool(mutex->sem);
-                    mutex->sem = MACH_PORT_NULL;
-               }
-                if (slowpath && (mutex->type == PTHREAD_MUTEX_RECURSIVE))
-                    mutex->lock_count = 1;
-                UNLOCK(mutex->lock);
-                return (ESUCCESS);
-        }
+       UNLOCK(mutex->lock);
+       return (ESUCCESS);
 }
 
 /*
@@ -271,67 +339,63 @@ pthread_mutex_trylock(pthread_mutex_t *mutex)
 int
 pthread_mutex_unlock(pthread_mutex_t *mutex)
 {
-        kern_return_t kern_res;
-        int waiters;
-        pthread_t self;
-       int slowpath;
-        
-        if (mutex->sig == _PTHREAD_MUTEX_SIG_init)
-        {
-                int res;
-                if (res = pthread_mutex_init(mutex, NULL))
-                        return (res);
-        }
-        if (mutex->sig != _PTHREAD_MUTEX_SIG)
-                return (EINVAL);        /* Not a mutex variable */
+       kern_return_t kern_res;
+       int waiters;
+       int sig = mutex->sig; 
 
-#if !defined(DEBUG)
-       if (mutex->def) {
-               slowpath = 0;
-               self = (pthread_t)0x12141968;
-       } else 
-#endif /* DEBUG */
+       /* To provide backwards compat for apps using mutex incorrectly */
+       
+       if ((sig != _PTHREAD_MUTEX_SIG) && (sig != _PTHREAD_MUTEX_SIG_init))
+               return(EINVAL);
+       LOCK(mutex->lock);
+       if (mutex->sig != _PTHREAD_MUTEX_SIG)
        {
-               slowpath = 1;
-               self = pthread_self();
-       }
-
-        LOCK(mutex->lock);
+               if (mutex->sig != _PTHREAD_MUTEX_SIG_init)
+               {
+                       UNLOCK(mutex->lock);
+                       return (EINVAL);        /* Not a mutex variable */
+               }
+               _pthread_mutex_init(mutex, NULL);
+       } else
 
-#if defined(DEBUG)
-       if (mutex->owner != self)
-#else
-        if (slowpath 
-               && ((mutex->type == PTHREAD_MUTEX_ERRORCHECK ) 
-                       || (mutex->type == PTHREAD_MUTEX_RECURSIVE )) 
-               && (mutex->owner != self)) 
-#endif /* DEBUG */
+#if !defined(DEBUG)
+       if (mutex->type != PTHREAD_MUTEX_NORMAL)
+#endif
        {
-               UNLOCK(mutex->lock);
+               pthread_t self = pthread_self();
+               if (mutex->owner != self)
+               {
 #if defined(DEBUG)
-               abort();
+                       abort();
 #endif
-               return(EPERM);
-        }
-        
-        if (slowpath && (mutex->type == PTHREAD_MUTEX_RECURSIVE)  && --mutex->lock_count) {
-                UNLOCK(mutex->lock);
-               return (ESUCCESS);
-            
-        } else {
+                       UNLOCK(mutex->lock);
+                       return EPERM;
+               } else if (mutex->type == PTHREAD_MUTEX_RECURSIVE &&
+                   --mutex->lock_count)
+               {
+                       UNLOCK(mutex->lock);
+                       return ESUCCESS;
+               }
+       }
+
+       mutex->lock_count = 0;
 #if defined(DEBUG)
-                _pthread_mutex_remove(mutex, mutex->owner);
+       _pthread_mutex_remove(mutex, mutex->owner);
 #endif /* DEBUG */
-                waiters = mutex->waiters;
-                mutex->owner = (pthread_t)NULL;
+
+       waiters = mutex->waiters;
+       if (waiters)
+       {
+               mutex->owner = _PTHREAD_MUTEX_OWNER_SWITCHING;
                UNLOCK(mutex->lock);
-                if (waiters)
-                {
-                   PTHREAD_MACH_CALL(semaphore_signal(mutex->sem), kern_res);
-                }
-                return (ESUCCESS);
-        
-        }
+               PTHREAD_MACH_CALL(semaphore_signal(mutex->sem), kern_res);
+       }
+       else
+       {
+               mutex->owner = (pthread_t)NULL;
+               UNLOCK(mutex->lock);
+       }
+       return (ESUCCESS);
 }
 
 /*
@@ -342,14 +406,17 @@ int
 pthread_mutex_getprioceiling(const pthread_mutex_t *mutex,
                              int *prioceiling)
 {
+       int res;
+
+       LOCK(mutex->lock);
         if (mutex->sig == _PTHREAD_MUTEX_SIG)
         {
                 *prioceiling = mutex->prioceiling;
-                return (ESUCCESS);
+                res = ESUCCESS;
         } else
-        {
-                return (EINVAL); /* Not an initialized 'attribute' structure */
-        }
+                res = EINVAL; /* Not an initialized 'attribute' structure */
+       UNLOCK(mutex->lock);
+       return (res);
 }
 
 /*
@@ -361,6 +428,9 @@ pthread_mutex_setprioceiling(pthread_mutex_t *mutex,
                              int prioceiling,
                              int *old_prioceiling)
 {
+       int res;
+
+       LOCK(mutex->lock);
         if (mutex->sig == _PTHREAD_MUTEX_SIG)
         {
                 if ((prioceiling >= -999) ||
@@ -368,15 +438,13 @@ pthread_mutex_setprioceiling(pthread_mutex_t *mutex,
                 {
                         *old_prioceiling = mutex->prioceiling;
                         mutex->prioceiling = prioceiling;
-                        return (ESUCCESS);
+                        res = ESUCCESS;
                 } else
-                {
-                        return (EINVAL); /* Invalid parameter */
-                }
+                        res = EINVAL; /* Invalid parameter */
         } else
-        {
-                return (EINVAL); /* Not an initialized 'attribute' structure */
-        }
+                res = EINVAL; /* Not an initialized 'attribute' structure */
+       UNLOCK(mutex->lock);
+       return (res);
 }
 
 /*