/* GLIB - Library of useful routines for C programming * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald * * gmutex.c: MT safety related functions * Copyright 1998 Sebastian Wilhelmi; University of Karlsruhe * Owen Taylor * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. */ /* * Modified by the GLib Team and others 1997-2000. See the AUTHORS * file for a list of people on the GLib Team. See the ChangeLog * files for a list of changes. These files are distributed with * GLib at ftp://ftp.gtk.org/pub/gtk/. */ /* * MT safe */ #include "config.h" #include "glib.h" #ifdef G_THREAD_USE_PID_SURROGATE #include #include #include #include #endif /* G_THREAD_USE_PID_SURROGATE */ #ifdef HAVE_UNISTD_H #include #endif #include #if GLIB_SIZEOF_SYSTEM_THREAD == SIZEOF_VOID_P # define g_system_thread_equal_simple(thread1, thread2) \ ((thread1).dummy_pointer == (thread2).dummy_pointer) # define g_system_thread_assign(dest, src) \ ((dest).dummy_pointer = (src).dummy_pointer) #else /* GLIB_SIZEOF_SYSTEM_THREAD != SIZEOF_VOID_P */ # define g_system_thread_equal_simple(thread1, thread2) \ (memcmp (&(thread1), &(thread2), GLIB_SIZEOF_SYSTEM_THREAD) == 0) # define g_system_thread_assign(dest, src) \ (memcpy (&(dest), &(src), GLIB_SIZEOF_SYSTEM_THREAD)) #endif /* GLIB_SIZEOF_SYSTEM_THREAD == SIZEOF_VOID_P */ #define g_system_thread_equal(thread1, thread2) \ (g_thread_functions_for_glib_use.thread_equal ? \ g_thread_functions_for_glib_use.thread_equal (&(thread1), &(thread2)) :\ g_system_thread_equal_simple((thread1), (thread2))) GQuark g_thread_error_quark (void) { static GQuark quark; if (!quark) quark = g_quark_from_static_string ("g_thread_error"); return quark; } /* Keep this in sync with GRealThread in gmain.c! */ typedef struct _GRealThread GRealThread; struct _GRealThread { GThread thread; gpointer private_data; gpointer retval; GSystemThread system_thread; #ifdef G_THREAD_USE_PID_SURROGATE pid_t pid; #endif /* G_THREAD_USE_PID_SURROGATE */ }; #ifdef G_THREAD_USE_PID_SURROGATE static gint priority_map[] = { 15, 0, -15, -20 }; static gboolean prio_warned = FALSE; # define SET_PRIO(pid, prio) G_STMT_START{ \ gint error = setpriority (PRIO_PROCESS, (pid), priority_map[prio]); \ if (error == -1 && errno == EACCES && !prio_warned) \ { \ prio_warned = TRUE; \ g_warning ("Priorities can only be increased by root."); \ } \ }G_STMT_END #endif /* G_THREAD_USE_PID_SURROGATE */ typedef struct _GStaticPrivateNode GStaticPrivateNode; struct _GStaticPrivateNode { gpointer data; GDestroyNotify destroy; }; static void g_thread_cleanup (gpointer data); static void g_thread_fail (void); /* Global variables */ static GSystemThread zero_thread; /* This is initialized to all zero */ gboolean g_thread_use_default_impl = TRUE; gboolean g_threads_got_initialized = FALSE; #if defined(G_PLATFORM_WIN32) && defined(__GNUC__) __declspec(dllexport) #endif GThreadFunctions g_thread_functions_for_glib_use = { (GMutex*(*)(void))g_thread_fail, /* mutex_new */ NULL, /* mutex_lock */ NULL, /* mutex_trylock */ NULL, /* mutex_unlock */ NULL, /* mutex_free */ (GCond*(*)(void))g_thread_fail, /* cond_new */ NULL, /* cond_signal */ NULL, /* cond_broadcast */ NULL, /* cond_wait */ NULL, /* cond_timed_wait */ NULL, /* cond_free */ (GPrivate*(*)(GDestroyNotify))g_thread_fail, /* private_new */ NULL, /* private_get */ NULL, /* private_set */ (void(*)(GThreadFunc, gpointer, gulong, gboolean, gboolean, GThreadPriority, gpointer, GError**))g_thread_fail, /* thread_create */ NULL, /* thread_yield */ NULL, /* thread_join */ NULL, /* thread_exit */ NULL, /* thread_set_priority */ NULL /* thread_self */ }; /* Local data */ static GMutex *g_mutex_protect_static_mutex_allocation = NULL; static GPrivate *g_thread_specific_private = NULL; static GSList *g_thread_all_threads = NULL; static GSList *g_thread_free_indeces = NULL; G_LOCK_DEFINE_STATIC (g_thread); /* This must be called only once, before any threads are created. * It will only be called from g_thread_init() in -lgthread. */ void g_mutex_init (void) { GRealThread* main_thread; /* We let the main thread (the one that calls g_thread_init) inherit * the data, that it set before calling g_thread_init */ main_thread = (GRealThread*) g_thread_self (); g_thread_specific_private = g_private_new (g_thread_cleanup); G_THREAD_UF (private_set, (g_thread_specific_private, main_thread)); G_THREAD_UF (thread_self, (&main_thread->system_thread)); g_mutex_protect_static_mutex_allocation = g_mutex_new (); } void g_static_mutex_init (GStaticMutex *mutex) { static GStaticMutex init_mutex = G_STATIC_MUTEX_INIT; g_return_if_fail (mutex); *mutex = init_mutex; } GMutex * g_static_mutex_get_mutex_impl (GMutex** mutex) { if (!g_thread_supported ()) return NULL; g_assert (g_mutex_protect_static_mutex_allocation); g_mutex_lock (g_mutex_protect_static_mutex_allocation); if (!(*mutex)) *mutex = g_mutex_new (); g_mutex_unlock (g_mutex_protect_static_mutex_allocation); return *mutex; } void g_static_mutex_free (GStaticMutex* mutex) { GMutex **runtime_mutex; g_return_if_fail (mutex); /* The runtime_mutex is the first (or only) member of GStaticMutex, * see both versions (of glibconfig.h) in configure.in */ runtime_mutex = ((GMutex**)mutex); if (*runtime_mutex) g_mutex_free (*runtime_mutex); *runtime_mutex = NULL; } void g_static_rec_mutex_init (GStaticRecMutex *mutex) { static GStaticRecMutex init_mutex = G_STATIC_REC_MUTEX_INIT; g_return_if_fail (mutex); *mutex = init_mutex; } void g_static_rec_mutex_lock (GStaticRecMutex* mutex) { GSystemThread self; g_return_if_fail (mutex); if (!g_thread_supported ()) return; G_THREAD_UF (thread_self, (&self)); if (g_system_thread_equal (self, mutex->owner)) { mutex->depth++; return; } g_static_mutex_lock (&mutex->mutex); g_system_thread_assign (mutex->owner, self); mutex->depth = 1; } gboolean g_static_rec_mutex_trylock (GStaticRecMutex* mutex) { GSystemThread self; g_return_val_if_fail (mutex, FALSE); if (!g_thread_supported ()) return TRUE; G_THREAD_UF (thread_self, (&self)); if (g_system_thread_equal (self, mutex->owner)) { mutex->depth++; return TRUE; } if (!g_static_mutex_trylock (&mutex->mutex)) return FALSE; g_system_thread_assign (mutex->owner, self); mutex->depth = 1; return TRUE; } void g_static_rec_mutex_unlock (GStaticRecMutex* mutex) { g_return_if_fail (mutex); if (!g_thread_supported ()) return; if (mutex->depth > 1) { mutex->depth--; return; } g_system_thread_assign (mutex->owner, zero_thread); g_static_mutex_unlock (&mutex->mutex); } void g_static_rec_mutex_lock_full (GStaticRecMutex *mutex, guint depth) { GSystemThread self; g_return_if_fail (mutex); if (!g_thread_supported ()) return; G_THREAD_UF (thread_self, (&self)); if (g_system_thread_equal (self, mutex->owner)) { mutex->depth += depth; return; } g_static_mutex_lock (&mutex->mutex); g_system_thread_assign (mutex->owner, self); mutex->depth = depth; } guint g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex) { gint depth; g_return_val_if_fail (mutex, 0); if (!g_thread_supported ()) return 1; depth = mutex->depth; g_system_thread_assign (mutex->owner, zero_thread); mutex->depth = 0; g_static_mutex_unlock (&mutex->mutex); return depth; } void g_static_rec_mutex_free (GStaticRecMutex *mutex) { g_return_if_fail (mutex); g_static_mutex_free (&mutex->mutex); } void g_static_private_init (GStaticPrivate *private_key) { private_key->index = 0; } gpointer g_static_private_get (GStaticPrivate *private_key) { GRealThread *self = (GRealThread*) g_thread_self (); GArray *array; array = self->private_data; if (!array) return NULL; if (!private_key->index) return NULL; else if (private_key->index <= array->len) return g_array_index (array, GStaticPrivateNode, private_key->index - 1).data; else return NULL; } void g_static_private_set (GStaticPrivate *private_key, gpointer data, GDestroyNotify notify) { GRealThread *self = (GRealThread*) g_thread_self (); GArray *array; static guint next_index = 0; GStaticPrivateNode *node; array = self->private_data; if (!array) { array = g_array_new (FALSE, TRUE, sizeof (GStaticPrivateNode)); self->private_data = array; } if (!private_key->index) { G_LOCK (g_thread); if (!private_key->index) { if (g_thread_free_indeces) { private_key->index = GPOINTER_TO_UINT (g_thread_free_indeces->data); g_thread_free_indeces = g_slist_delete_link (g_thread_free_indeces, g_thread_free_indeces); } else private_key->index = ++next_index; } G_UNLOCK (g_thread); } if (private_key->index > array->len) g_array_set_size (array, private_key->index); node = &g_array_index (array, GStaticPrivateNode, private_key->index - 1); if (node->destroy) { gpointer ddata = node->data; GDestroyNotify ddestroy = node->destroy; node->data = data; node->destroy = notify; ddestroy (ddata); } else { node->data = data; node->destroy = notify; } } void g_static_private_free (GStaticPrivate *private_key) { guint index = private_key->index; GSList *list; if (!index) return; private_key->index = 0; G_LOCK (g_thread); list = g_thread_all_threads; while (list) { GRealThread *thread = list->data; GArray *array = thread->private_data; list = list->next; if (array && index <= array->len) { GStaticPrivateNode *node = &g_array_index (array, GStaticPrivateNode, index - 1); gpointer ddata = node->data; GDestroyNotify ddestroy = node->destroy; node->data = NULL; node->destroy = NULL; if (ddestroy) { G_UNLOCK (g_thread); ddestroy (ddata); G_LOCK (g_thread); } } } g_thread_free_indeces = g_slist_prepend (g_thread_free_indeces, GUINT_TO_POINTER (index)); G_UNLOCK (g_thread); } static void g_thread_cleanup (gpointer data) { if (data) { GRealThread* thread = data; if (thread->private_data) { GArray* array = thread->private_data; guint i; for (i = 0; i < array->len; i++ ) { GStaticPrivateNode *node = &g_array_index (array, GStaticPrivateNode, i); if (node->destroy) node->destroy (node->data); } g_array_free (array, TRUE); } /* We only free the thread structure, if it isn't joinable. If it is, the structure is freed in g_thread_join */ if (!thread->thread.joinable) { G_LOCK (g_thread); g_thread_all_threads = g_slist_remove (g_thread_all_threads, data); G_UNLOCK (g_thread); /* Just to make sure, this isn't used any more */ g_system_thread_assign (thread->system_thread, zero_thread); g_free (thread); } } } static void g_thread_fail (void) { g_error ("The thread system is not yet initialized."); } static gpointer g_thread_create_proxy (gpointer data) { GRealThread* thread = data; g_assert (data); #ifdef G_THREAD_USE_PID_SURROGATE thread->pid = getpid (); #endif /* G_THREAD_USE_PID_SURROGATE */ /* This has to happen before G_LOCK, as that might call g_thread_self */ g_private_set (g_thread_specific_private, data); /* the lock makes sure, that thread->system_thread is written, before thread->thread.func is called. See g_thread_create. */ G_LOCK (g_thread); G_UNLOCK (g_thread); #ifdef G_THREAD_USE_PID_SURROGATE if (g_thread_use_default_impl) SET_PRIO (thread->pid, thread->thread.priority); #endif /* G_THREAD_USE_PID_SURROGATE */ thread->retval = thread->thread.func (thread->thread.data); return NULL; } GThread* g_thread_create_full (GThreadFunc func, gpointer data, gulong stack_size, gboolean joinable, gboolean bound, GThreadPriority priority, GError **error) { GRealThread* result = g_new (GRealThread, 1); GError *local_error = NULL; g_return_val_if_fail (func, NULL); g_return_val_if_fail (priority >= G_THREAD_PRIORITY_LOW, NULL); g_return_val_if_fail (priority <= G_THREAD_PRIORITY_URGENT, NULL); result->thread.joinable = joinable; result->thread.priority = priority; result->thread.func = func; result->thread.data = data; result->private_data = NULL; G_LOCK (g_thread); G_THREAD_UF (thread_create, (g_thread_create_proxy, result, stack_size, joinable, bound, priority, &result->system_thread, &local_error)); g_thread_all_threads = g_slist_prepend (g_thread_all_threads, result); G_UNLOCK (g_thread); if (local_error) { g_propagate_error (error, local_error); g_free (result); return NULL; } return (GThread*) result; } void g_thread_exit (gpointer retval) { GRealThread* real = (GRealThread*) g_thread_self (); real->retval = retval; G_THREAD_CF (thread_exit, (void)0, ()); } gpointer g_thread_join (GThread* thread) { GRealThread* real = (GRealThread*) thread; gpointer retval; g_return_val_if_fail (thread, NULL); g_return_val_if_fail (thread->joinable, NULL); g_return_val_if_fail (!g_system_thread_equal (real->system_thread, zero_thread), NULL); G_THREAD_UF (thread_join, (&real->system_thread)); retval = real->retval; G_LOCK (g_thread); g_thread_all_threads = g_slist_remove (g_thread_all_threads, thread); G_UNLOCK (g_thread); /* Just to make sure, this isn't used any more */ thread->joinable = 0; g_system_thread_assign (real->system_thread, zero_thread); /* the thread structure for non-joinable threads is freed upon thread end. We free the memory here. This will leave a loose end, if a joinable thread is not joined. */ g_free (thread); return retval; } void g_thread_set_priority (GThread* thread, GThreadPriority priority) { GRealThread* real = (GRealThread*) thread; g_return_if_fail (thread); g_return_if_fail (!g_system_thread_equal (real->system_thread, zero_thread)); g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW); g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT); thread->priority = priority; #ifdef G_THREAD_USE_PID_SURROGATE if (g_thread_use_default_impl) SET_PRIO (real->pid, priority); else #endif /* G_THREAD_USE_PID_SURROGATE */ G_THREAD_CF (thread_set_priority, (void)0, (&real->system_thread, priority)); } GThread* g_thread_self (void) { GRealThread* thread = g_private_get (g_thread_specific_private); if (!thread) { /* If no thread data is available, provide and set one. This can happen for the main thread and for threads, that are not created by GLib. */ thread = g_new (GRealThread, 1); thread->thread.joinable = FALSE; /* This is a save guess */ thread->thread.priority = G_THREAD_PRIORITY_NORMAL; /* This is just a guess */ thread->thread.func = NULL; thread->thread.data = NULL; thread->private_data = NULL; if (g_thread_supported ()) G_THREAD_UF (thread_self, (&thread->system_thread)); #ifdef G_THREAD_USE_PID_SURROGATE thread->pid = getpid (); #endif /* G_THREAD_USE_PID_SURROGATE */ g_private_set (g_thread_specific_private, thread); G_LOCK (g_thread); g_thread_all_threads = g_slist_prepend (g_thread_all_threads, thread); G_UNLOCK (g_thread); } return (GThread*)thread; } void g_static_rw_lock_init (GStaticRWLock* lock) { static GStaticRWLock init_lock = G_STATIC_RW_LOCK_INIT; g_return_if_fail (lock); *lock = init_lock; } static void inline g_static_rw_lock_wait (GCond** cond, GStaticMutex* mutex) { if (!*cond) *cond = g_cond_new (); g_cond_wait (*cond, g_static_mutex_get_mutex (mutex)); } static void inline g_static_rw_lock_signal (GStaticRWLock* lock) { if (lock->want_to_write && lock->write_cond) g_cond_signal (lock->write_cond); else if (lock->want_to_read && lock->read_cond) g_cond_broadcast (lock->read_cond); } void g_static_rw_lock_reader_lock (GStaticRWLock* lock) { g_return_if_fail (lock); if (!g_threads_got_initialized) return; g_static_mutex_lock (&lock->mutex); lock->want_to_read++; while (lock->write || lock->want_to_write) g_static_rw_lock_wait (&lock->read_cond, &lock->mutex); lock->want_to_read--; lock->read_counter++; g_static_mutex_unlock (&lock->mutex); } gboolean g_static_rw_lock_reader_trylock (GStaticRWLock* lock) { gboolean ret_val = FALSE; g_return_val_if_fail (lock, FALSE); if (!g_threads_got_initialized) return TRUE; g_static_mutex_lock (&lock->mutex); if (!lock->write && !lock->want_to_write) { lock->read_counter++; ret_val = TRUE; } g_static_mutex_unlock (&lock->mutex); return ret_val; } void g_static_rw_lock_reader_unlock (GStaticRWLock* lock) { g_return_if_fail (lock); if (!g_threads_got_initialized) return; g_static_mutex_lock (&lock->mutex); lock->read_counter--; if (lock->read_counter == 0) g_static_rw_lock_signal (lock); g_static_mutex_unlock (&lock->mutex); } void g_static_rw_lock_writer_lock (GStaticRWLock* lock) { g_return_if_fail (lock); if (!g_threads_got_initialized) return; g_static_mutex_lock (&lock->mutex); lock->want_to_write++; while (lock->write || lock->read_counter) g_static_rw_lock_wait (&lock->write_cond, &lock->mutex); lock->want_to_write--; lock->write = TRUE; g_static_mutex_unlock (&lock->mutex); } gboolean g_static_rw_lock_writer_trylock (GStaticRWLock* lock) { gboolean ret_val = FALSE; g_return_val_if_fail (lock, FALSE); if (!g_threads_got_initialized) return TRUE; g_static_mutex_lock (&lock->mutex); if (!lock->write && !lock->read_counter) { lock->write = TRUE; ret_val = TRUE; } g_static_mutex_unlock (&lock->mutex); return ret_val; } void g_static_rw_lock_writer_unlock (GStaticRWLock* lock) { g_return_if_fail (lock); if (!g_threads_got_initialized) return; g_static_mutex_lock (&lock->mutex); lock->write = FALSE; g_static_rw_lock_signal (lock); g_static_mutex_unlock (&lock->mutex); } void g_static_rw_lock_free (GStaticRWLock* lock) { g_return_if_fail (lock); if (lock->read_cond) { g_cond_free (lock->read_cond); lock->read_cond = NULL; } if (lock->write_cond) { g_cond_free (lock->write_cond); lock->write_cond = NULL; } g_static_mutex_free (&lock->mutex); }