gthread/gthread-impl.c

   1 /* GLIB - Library of useful routines for C programming
   2  * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
   3  *
   4  * gthread.c: thread related functions
   5  * Copyright 1998 Sebastian Wilhelmi; University of Karlsruhe
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with this library; if not, write to the
  19  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  20  * Boston, MA 02111-1307, USA.
  21  */
  22
  23 /*
  24  * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
  25  * file for a list of people on the GLib Team.  See the ChangeLog
  26  * files for a list of changes.  These files are distributed with
  27  * GLib at ftp://ftp.gtk.org/pub/gtk/.
  28  */
  29
  30 /*
  31  * MT safe
  32  */
  33
  34 #ifdef HAVE_CONFIG_H
  35 #include <config.h>
  36 #endif
  37
  38 #include <glib.h>
  39 #include <gthreadinit.h>
  40
  41 #ifdef G_THREADS_ENABLED
  42
  43 static gboolean thread_system_already_initialized = FALSE;
  44 static gint g_thread_priority_map [G_THREAD_PRIORITY_URGENT + 1];
  45
  46 #include G_THREAD_SOURCE
  47
  48 #ifndef PRIORITY_LOW_VALUE
  49 # define PRIORITY_LOW_VALUE 0
  50 #endif
  51
  52 #ifndef PRIORITY_URGENT_VALUE
  53 # define PRIORITY_URGENT_VALUE 0
  54 #endif
  55
  56 #ifndef PRIORITY_NORMAL_VALUE
  57 # define PRIORITY_NORMAL_VALUE                                          \
  58   ((PRIORITY_LOW_VALUE * 6 + PRIORITY_URGENT_VALUE * 4) / 10)
  59 #endif /* PRIORITY_NORMAL_VALUE */
  60
  61 #ifndef PRIORITY_HIGH_VALUE
  62 # define PRIORITY_HIGH_VALUE                                            \
  63   ((PRIORITY_NORMAL_VALUE + PRIORITY_URGENT_VALUE * 2) / 3)
  64 #endif /* PRIORITY_HIGH_VALUE */
  65
  66 void g_mutex_init (void);
  67 void g_mem_init (void);
  68 void g_messages_init (void);
  69 void g_convert_init (void);
  70 void g_rand_init (void);
  71 void g_main_thread_init (void);
  72
  73 #define G_MUTEX_DEBUG_INFO(mutex) (*((gpointer*)(((char*)mutex)+G_MUTEX_SIZE)))
  74
  75 typedef struct _ErrorCheckInfo ErrorCheckInfo;
  76 struct _ErrorCheckInfo
  77 {
  78   gchar *location;
  79   GThread *owner;
  80 };
  81
  82 static GMutex *
  83 g_mutex_new_errorcheck_impl (void)
  84 {
  85   GMutex *retval = g_thread_functions_for_glib_use_default.mutex_new ();
  86   retval = g_realloc (retval, G_MUTEX_SIZE + sizeof (gpointer));
  87   G_MUTEX_DEBUG_INFO (retval) = NULL;
  88   return retval;
  89 }
  90
  91 static void
  92 g_mutex_lock_errorcheck_impl (GMutex *mutex,
  93                               gulong magic,
  94                               gchar *location)
  95 {
  96   ErrorCheckInfo *info;
  97   GThread *self = g_thread_self ();
  98
  99   if (magic != G_MUTEX_DEBUG_MAGIC)
 100     location = "unknown";
 101
 102   if (G_MUTEX_DEBUG_INFO (mutex) == NULL)
 103     {
 104       /* if the debug info is NULL, we have not yet locked that mutex,
 105        * so we do it now */
 106       g_thread_functions_for_glib_use_default.mutex_lock (mutex);
 107       /* Now we have to check again, because another thread might have
 108        * tried to lock the mutex at the same time we did. This
 109        * technique is not 100% save on systems without decent cache
 110        * coherence, but we have no choice */
 111       if (G_MUTEX_DEBUG_INFO (mutex) == NULL)
 112         {
 113           info = G_MUTEX_DEBUG_INFO (mutex) = g_new0 (ErrorCheckInfo, 1);
 114         }
 115       g_thread_functions_for_glib_use_default.mutex_unlock (mutex);
 116     }
 117
 118   info = G_MUTEX_DEBUG_INFO (mutex);
 119   if (info->owner == self)
 120     g_error ("Trying to recursivly lock a mutex at '%s', "
 121              "previously locked at '%s'",
 122              location, info->location);
 123
 124   g_thread_functions_for_glib_use_default.mutex_lock (mutex);
 125
 126   info->owner = self;
 127   info->location = location;
 128 }
 129
 130 static gboolean
 131 g_mutex_trylock_errorcheck_impl (GMutex *mutex,
 132                                  gulong magic,
 133                                  gchar *location)
 134 {
 135   ErrorCheckInfo *info = G_MUTEX_DEBUG_INFO (mutex);
 136   GThread *self = g_thread_self ();
 137
 138   if (magic != G_MUTEX_DEBUG_MAGIC)
 139     location = "unknown";
 140
 141   if (!info)
 142     {
 143       /* This mutex has not yet been used, so simply lock and return TRUE */
 144       g_mutex_lock_errorcheck_impl (mutex, magic, location);
 145       return TRUE;
 146     }
 147
 148   if (info->owner == self)
 149     g_error ("Trying to recursivly lock a mutex at '%s', "
 150              "previously locked at '%s'",
 151              location, info->location);
 152
 153   if (!g_thread_functions_for_glib_use_default.mutex_trylock (mutex))
 154     return FALSE;
 155
 156   info->owner = self;
 157   info->location = location;
 158
 159   return TRUE;
 160 }
 161
 162 static void
 163 g_mutex_unlock_errorcheck_impl (GMutex *mutex,
 164                                 gulong magic,
 165                                 gchar *location)
 166 {
 167   ErrorCheckInfo *info = G_MUTEX_DEBUG_INFO (mutex);
 168   GThread *self = g_thread_self ();
 169
 170   if (magic != G_MUTEX_DEBUG_MAGIC)
 171     location = "unknown";
 172
 173   if (!info || info->owner == NULL)
 174     g_error ("Trying to unlock an unlocked mutex at '%s'", location);
 175
 176   if (info->owner != self)
 177     g_warning ("Trying to unlock a mutex at '%s', "
 178                "previously locked by a different thread at '%s'",
 179                location, info->location);
 180
 181   info->owner = NULL;
 182   info->location = NULL;
 183
 184   g_thread_functions_for_glib_use_default.mutex_unlock (mutex);
 185 }
 186
 187 static void
 188 g_mutex_free_errorcheck_impl (GMutex *mutex,
 189                               gulong magic,
 190                               gchar *location)
 191 {
 192   ErrorCheckInfo *info = G_MUTEX_DEBUG_INFO (mutex);
 193
 194   if (magic != G_MUTEX_DEBUG_MAGIC)
 195     location = "unknown";
 196
 197   if (info && info->owner != NULL)
 198     g_error ("Trying to free a locked mutex at '%s', "
 199              "which was previously locked at '%s'",
 200              location, info->location);
 201
 202   g_free (G_MUTEX_DEBUG_INFO (mutex));
 203   g_thread_functions_for_glib_use_default.mutex_free (mutex);
 204 }
 205
 206 static void
 207 g_cond_wait_errorcheck_impl (GCond *cond,
 208                              GMutex *mutex,
 209                              gulong magic,
 210                              gchar *location)
 211 {
 212
 213   ErrorCheckInfo *info = G_MUTEX_DEBUG_INFO (mutex);
 214   GThread *self = g_thread_self ();
 215
 216   if (magic != G_MUTEX_DEBUG_MAGIC)
 217     location = "unknown";
 218
 219   if (!info || info->owner == NULL)
 220     g_error ("Trying to use an unlocked mutex in g_cond_wait() at '%s'",
 221              location);
 222
 223   if (info->owner != self)
 224     g_error ("Trying to use a mutex locked by another thread in "
 225              "g_cond_wait() at '%s'", location);
 226
 227   info->owner = NULL;
 228   location = info->location;
 229
 230   g_thread_functions_for_glib_use_default.cond_wait (cond, mutex);
 231
 232   info->owner = self;
 233   info->location = location;
 234 }
 235
 236
 237 static gboolean
 238 g_cond_timed_wait_errorcheck_impl (GCond *cond,
 239                                    GMutex *mutex,
 240                                    GTimeVal *end_time,
 241                                    gulong magic,
 242                                    gchar *location)
 243 {
 244   ErrorCheckInfo *info = G_MUTEX_DEBUG_INFO (mutex);
 245   GThread *self = g_thread_self ();
 246   gboolean retval;
 247
 248   if (magic != G_MUTEX_DEBUG_MAGIC)
 249     location = "unknown";
 250
 251   if (!info || info->owner == NULL)
 252     g_error ("Trying to use an unlocked mutex in g_cond_timed_wait() at '%s'",
 253              location);
 254
 255   if (info->owner != self)
 256     g_error ("Trying to use a mutex locked by another thread in "
 257              "g_cond_timed_wait() at '%s'", location);
 258
 259   info->owner = NULL;
 260   location = info->location;
 261
 262   retval = g_thread_functions_for_glib_use_default.cond_timed_wait (cond,
 263                                                                     mutex,
 264                                                                     end_time);
 265
 266   info->owner = self;
 267   info->location = location;
 268
 269   return retval;
 270 }
 271
 272
 273 /* unshadow function declaration. See gthread.h */
 274 #undef g_thread_init
 275
 276 void
 277 g_thread_init_with_errorcheck_mutexes (GThreadFunctions* init)
 278 {
 279   GThreadFunctions errorcheck_functions;
 280   if (init)
 281     g_error ("Errorcheck mutexes can only be used for native "
 282              "thread implementations. Sorry." );
 283
 284 #ifdef HAVE_G_THREAD_IMPL_INIT
 285   /* This isn't called in g_thread_init, as it doesn't think to get
 286    * the default implementation, so we have to call it on our own.
 287    *
 288    * We must call this before copying
 289    * g_thread_functions_for_glib_use_default as the
 290    * implementation-specific init function might modify the contents
 291    * of g_thread_functions_for_glib_use_default based on operating
 292    * system version, C library version, or whatever. */
 293   g_thread_impl_init();
 294 #endif /* HAVE_G_THREAD_IMPL_INIT */
 295
 296   errorcheck_functions = g_thread_functions_for_glib_use_default;
 297   errorcheck_functions.mutex_new = g_mutex_new_errorcheck_impl;
 298   errorcheck_functions.mutex_lock =
 299     (void (*)(GMutex *)) g_mutex_lock_errorcheck_impl;
 300   errorcheck_functions.mutex_trylock =
 301     (gboolean (*)(GMutex *)) g_mutex_trylock_errorcheck_impl;
 302   errorcheck_functions.mutex_unlock =
 303     (void (*)(GMutex *)) g_mutex_unlock_errorcheck_impl;
 304   errorcheck_functions.mutex_free =
 305     (void (*)(GMutex *)) g_mutex_free_errorcheck_impl;
 306   errorcheck_functions.cond_wait =
 307     (void (*)(GCond *, GMutex *)) g_cond_wait_errorcheck_impl;
 308   errorcheck_functions.cond_timed_wait =
 309     (gboolean (*)(GCond *, GMutex *, GTimeVal *))
 310     g_cond_timed_wait_errorcheck_impl;
 311
 312   g_thread_init (&errorcheck_functions);
 313 }
 314
 315 void
 316 g_thread_init (GThreadFunctions* init)
 317 {
 318   gboolean supported;
 319
 320   if (thread_system_already_initialized)
 321     g_error ("GThread system may only be initialized once.");
 322
 323   thread_system_already_initialized = TRUE;
 324
 325   if (init == NULL)
 326     {
 327 #ifdef HAVE_G_THREAD_IMPL_INIT
 328       /* now do any initialization stuff required by the
 329        * implementation, but only if called with a NULL argument, of
 330        * course. Otherwise it's up to the user to do so. */
 331       g_thread_impl_init();
 332 #endif /* HAVE_G_THREAD_IMPL_INIT */
 333       init = &g_thread_functions_for_glib_use_default;
 334     }
 335   else
 336     g_thread_use_default_impl = FALSE;
 337
 338   g_thread_functions_for_glib_use = *init;
 339
 340   supported = (init->mutex_new &&
 341                init->mutex_lock &&
 342                init->mutex_trylock &&
 343                init->mutex_unlock &&
 344                init->mutex_free &&
 345                init->cond_new &&
 346                init->cond_signal &&
 347                init->cond_broadcast &&
 348                init->cond_wait &&
 349                init->cond_timed_wait &&
 350                init->cond_free &&
 351                init->private_new &&
 352                init->private_get &&
 353                init->private_set &&
 354                init->thread_create &&
 355                init->thread_yield &&
 356                init->thread_join &&
 357                init->thread_exit &&
 358                init->thread_set_priority &&
 359                init->thread_self);
 360
 361   /* if somebody is calling g_thread_init (), it means that he wants to
 362    * have thread support, so check this
 363    */
 364   if (!supported)
 365     {
 366       if (g_thread_use_default_impl)
 367         g_error ("Threads are not supported on this platform.");
 368       else
 369         g_error ("The supplied thread function vector is invalid.");
 370     }
 371
 372   g_thread_priority_map [G_THREAD_PRIORITY_LOW] = PRIORITY_LOW_VALUE;
 373   g_thread_priority_map [G_THREAD_PRIORITY_NORMAL] = PRIORITY_NORMAL_VALUE;
 374   g_thread_priority_map [G_THREAD_PRIORITY_HIGH] = PRIORITY_HIGH_VALUE;
 375   g_thread_priority_map [G_THREAD_PRIORITY_URGENT] = PRIORITY_URGENT_VALUE;
 376
 377   g_thread_init_glib ();
 378 }
 379
 380 #else /* !G_THREADS_ENABLED */
 381
 382 void
 383 g_thread_init (GThreadFunctions* init)
 384 {
 385   g_error ("GLib thread support is disabled.");
 386 }
 387
 388 #endif /* !G_THREADS_ENABLED */