gthread/gthread-posix.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: posix thread system implementation
   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 #include <pthread.h>
  35 #include <errno.h>
  36 #include <stdlib.h>
  37 #ifdef HAVE_SYS_TIME_H
  38 # include <sys/time.h>
  39 #endif
  40 #ifdef HAVE_UNISTD_H
  41 # include <unistd.h>
  42 #endif
  43
  44 #ifdef HAVE_SCHED_H
  45 #include <sched.h>
  46 #endif
  47
  48 #define posix_check_err(err, name) G_STMT_START{                        \
  49   int error = (err);                                                    \
  50   if (error)                                                            \
  51     g_error ("file %s: line %d (%s): error '%s' during '%s'",           \
  52            __FILE__, __LINE__, G_GNUC_PRETTY_FUNCTION,                  \
  53            g_strerror (error), name);                                   \
  54   }G_STMT_END
  55
  56 #define posix_check_cmd(cmd) posix_check_err (posix_error (cmd), #cmd)
  57
  58 #ifdef G_ENABLE_DEBUG
  59 static gboolean posix_check_cmd_prio_warned = FALSE;
  60 # define posix_check_cmd_prio(cmd) G_STMT_START{                        \
  61     int err = posix_error (cmd);                                        \
  62     if (err == EPERM)                                                   \
  63       {                                                                 \
  64         if (!posix_check_cmd_prio_warned)                               \
  65           {                                                             \
  66             posix_check_cmd_prio_warned = TRUE;                         \
  67             g_warning ("Priorities can only be changed "                \
  68                         "(resp. increased) by root.");                  \
  69           }                                                             \
  70       }                                                                 \
  71     else                                                                \
  72       posix_check_err (err, #cmd);                                      \
  73      }G_STMT_END
  74 #else /* G_ENABLE_DEBUG */
  75 # define posix_check_cmd_prio(cmd) G_STMT_START{                        \
  76     int err = posix_error (cmd);                                        \
  77     if (err != EPERM)                                                   \
  78       posix_check_err (err, #cmd);                                      \
  79      }G_STMT_END
  80 #endif /* G_ENABLE_DEBUG */
  81
  82 #if defined(G_THREADS_IMPL_POSIX)
  83 # define posix_error(what) (what)
  84 # define mutexattr_default NULL
  85 # define condattr_default NULL
  86 #elif defined(G_THREADS_IMPL_DCE)
  87 # define posix_error(what) ((what) == -1 ? errno : 0)
  88 # define pthread_key_create(a, b) pthread_keycreate (a, b)
  89 # define pthread_attr_init(a) pthread_attr_create (a)
  90 # define pthread_attr_destroy(a) pthread_attr_delete (a)
  91 # define pthread_create(a, b, c, d) pthread_create (a, *b, c, d)
  92 # define mutexattr_default (pthread_mutexattr_default)
  93 # define condattr_default (pthread_condattr_default)
  94 #else /* neither G_THREADS_IMPL_POSIX nor G_THREADS_IMPL_DCE are defined */
  95 # error This should not happen. Contact the GLib team.
  96 #endif
  97
  98 #if defined (POSIX_MIN_PRIORITY) && defined (POSIX_MAX_PRIORITY)
  99 # define HAVE_PRIORITIES 1
 100 # ifdef __FreeBSD__
 101    /* FreeBSD threads use different priority values from the POSIX_
 102     * defines so we just set them here. The corresponding macros
 103     * PTHREAD_MIN_PRIORITY and PTHREAD_MAX_PRIORITY are implied to be
 104     * exported by the docs, but they aren't.
 105     */
 106 #  define PRIORITY_LOW_VALUE      0
 107 #  define PRIORITY_URGENT_VALUE   31
 108 # else /* !__FreeBSD__ */
 109 #  define PRIORITY_LOW_VALUE POSIX_MIN_PRIORITY
 110 #  define PRIORITY_URGENT_VALUE POSIX_MAX_PRIORITY
 111 # endif /* !__FreeBSD__ */
 112 #endif /* POSIX_MIN_PRIORITY && POSIX_MAX_PRIORITY */
 113
 114 static gulong g_thread_min_stack_size = 0;
 115
 116 #define G_MUTEX_SIZE (sizeof (pthread_mutex_t))
 117
 118 #ifdef _SC_THREAD_STACK_MIN
 119 #define HAVE_G_THREAD_IMPL_INIT
 120 static void
 121 g_thread_impl_init()
 122 {
 123   g_thread_min_stack_size = MAX (sysconf (_SC_THREAD_STACK_MIN), 0);
 124 }
 125 #endif /* _SC_THREAD_STACK_MIN */
 126
 127 static GMutex *
 128 g_mutex_new_posix_impl (void)
 129 {
 130   GMutex *result = (GMutex *) g_new (pthread_mutex_t, 1);
 131   posix_check_cmd (pthread_mutex_init ((pthread_mutex_t *) result,
 132                                        mutexattr_default));
 133   return result;
 134 }
 135
 136 static void
 137 g_mutex_free_posix_impl (GMutex * mutex)
 138 {
 139   posix_check_cmd (pthread_mutex_destroy ((pthread_mutex_t *) mutex));
 140   g_free (mutex);
 141 }
 142
 143 /* NOTE: the functions g_mutex_lock and g_mutex_unlock may not use
 144    functions from gmem.c and gmessages.c; */
 145
 146 /* pthread_mutex_lock, pthread_mutex_unlock can be taken directly, as
 147    signature and semantic are right, but without error check then!!!!,
 148    we might want to change this therefore. */
 149
 150 static gboolean
 151 g_mutex_trylock_posix_impl (GMutex * mutex)
 152 {
 153   int result;
 154
 155   result = pthread_mutex_trylock ((pthread_mutex_t *) mutex);
 156
 157 #ifdef G_THREADS_IMPL_POSIX
 158   if (result == EBUSY)
 159     return FALSE;
 160 #else /* G_THREADS_IMPL_DCE */
 161   if (result == 0)
 162     return FALSE;
 163 #endif
 164
 165   posix_check_err (posix_error (result), "pthread_mutex_trylock");
 166   return TRUE;
 167 }
 168
 169 static GCond *
 170 g_cond_new_posix_impl (void)
 171 {
 172   GCond *result = (GCond *) g_new (pthread_cond_t, 1);
 173   posix_check_cmd (pthread_cond_init ((pthread_cond_t *) result,
 174                                       condattr_default));
 175   return result;
 176 }
 177
 178 /* pthread_cond_signal, pthread_cond_broadcast and pthread_cond_wait
 179    can be taken directly, as signature and semantic are right, but
 180    without error check then!!!!, we might want to change this
 181    therfore. */
 182
 183 #define G_NSEC_PER_SEC 1000000000
 184
 185 static gboolean
 186 g_cond_timed_wait_posix_impl (GCond * cond,
 187                               GMutex * entered_mutex,
 188                               GTimeVal * abs_time)
 189 {
 190   int result;
 191   struct timespec end_time;
 192   gboolean timed_out;
 193
 194   g_return_val_if_fail (cond != NULL, FALSE);
 195   g_return_val_if_fail (entered_mutex != NULL, FALSE);
 196
 197   if (!abs_time)
 198     {
 199       g_cond_wait (cond, entered_mutex);
 200       return TRUE;
 201     }
 202
 203   end_time.tv_sec = abs_time->tv_sec;
 204   end_time.tv_nsec = abs_time->tv_usec * (G_NSEC_PER_SEC / G_USEC_PER_SEC);
 205   g_assert (end_time.tv_nsec < G_NSEC_PER_SEC);
 206   result = pthread_cond_timedwait ((pthread_cond_t *) cond,
 207                                    (pthread_mutex_t *) entered_mutex,
 208                                    &end_time);
 209
 210 #ifdef G_THREADS_IMPL_POSIX
 211   timed_out = (result == ETIMEDOUT);
 212 #else /* G_THREADS_IMPL_DCE */
 213   timed_out = (result == -1) && (errno = EAGAIN);
 214 #endif
 215
 216   if (!timed_out)
 217     posix_check_err (posix_error (result), "pthread_cond_timedwait");
 218   return !timed_out;
 219 }
 220
 221 static void
 222 g_cond_free_posix_impl (GCond * cond)
 223 {
 224   posix_check_cmd (pthread_cond_destroy ((pthread_cond_t *) cond));
 225   g_free (cond);
 226 }
 227
 228 static GPrivate *
 229 g_private_new_posix_impl (GDestroyNotify destructor)
 230 {
 231   GPrivate *result = (GPrivate *) g_new (pthread_key_t, 1);
 232   posix_check_cmd (pthread_key_create ((pthread_key_t *) result, destructor));
 233   return result;
 234 }
 235
 236 /* NOTE: the functions g_private_get and g_private_set may not use
 237    functions from gmem.c and gmessages.c */
 238
 239 static void
 240 g_private_set_posix_impl (GPrivate * private_key, gpointer value)
 241 {
 242   if (!private_key)
 243     return;
 244   pthread_setspecific (*(pthread_key_t *) private_key, value);
 245 }
 246
 247 static gpointer
 248 g_private_get_posix_impl (GPrivate * private_key)
 249 {
 250   if (!private_key)
 251     return NULL;
 252 #ifdef G_THREADS_IMPL_POSIX
 253   return pthread_getspecific (*(pthread_key_t *) private_key);
 254 #else /* G_THREADS_IMPL_DCE */
 255   {
 256     void* data;
 257     posix_check_cmd (pthread_getspecific (*(pthread_key_t *) private_key,
 258                                           &data));
 259     return data;
 260   }
 261 #endif
 262 }
 263
 264 static void
 265 g_thread_create_posix_impl (GThreadFunc thread_func,
 266                             gpointer arg,
 267                             gulong stack_size,
 268                             gboolean joinable,
 269                             gboolean bound,
 270                             GThreadPriority priority,
 271                             gpointer thread,
 272                             GError **error)
 273 {
 274   pthread_attr_t attr;
 275   gint ret;
 276
 277   g_return_if_fail (thread_func);
 278   g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW);
 279   g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT);
 280
 281   posix_check_cmd (pthread_attr_init (&attr));
 282
 283 #ifdef HAVE_PTHREAD_ATTR_SETSTACKSIZE
 284   if (stack_size)
 285     {
 286       stack_size = MAX (g_thread_min_stack_size, stack_size);
 287       posix_check_cmd (pthread_attr_setstacksize (&attr, stack_size));
 288     }
 289 #endif /* HAVE_PTHREAD_ATTR_SETSTACKSIZE */
 290
 291 #ifdef PTHREAD_SCOPE_SYSTEM
 292   if (bound)
 293     /* No error check here, because some systems can't do it and we
 294      * simply don't want threads to fail because of that. */
 295     pthread_attr_setscope (&attr, PTHREAD_SCOPE_SYSTEM);
 296 #endif /* PTHREAD_SCOPE_SYSTEM */
 297
 298 #ifdef G_THREADS_IMPL_POSIX
 299   posix_check_cmd (pthread_attr_setdetachstate (&attr,
 300           joinable ? PTHREAD_CREATE_JOINABLE : PTHREAD_CREATE_DETACHED));
 301 #endif /* G_THREADS_IMPL_POSIX */
 302
 303 #ifdef HAVE_PRIORITIES
 304 # ifdef G_THREADS_IMPL_POSIX
 305   {
 306     struct sched_param sched;
 307     posix_check_cmd (pthread_attr_getschedparam (&attr, &sched));
 308     sched.sched_priority = g_thread_priority_map [priority];
 309     posix_check_cmd_prio (pthread_attr_setschedparam (&attr, &sched));
 310   }
 311 # else /* G_THREADS_IMPL_DCE */
 312   posix_check_cmd_prio
 313     (pthread_attr_setprio (&attr, g_thread_priority_map [priority]));
 314 # endif /* G_THREADS_IMPL_DCE */
 315 #endif /* HAVE_PRIORITIES */
 316   ret = posix_error (pthread_create (thread, &attr,
 317                                      (void* (*)(void*))thread_func, arg));
 318
 319   posix_check_cmd (pthread_attr_destroy (&attr));
 320
 321   if (ret == EAGAIN)
 322     {
 323       g_set_error (error, G_THREAD_ERROR, G_THREAD_ERROR_AGAIN,
 324                    "Error creating thread: %s", g_strerror (ret));
 325       return;
 326     }
 327
 328   posix_check_err (ret, "pthread_create");
 329
 330 #ifdef G_THREADS_IMPL_DCE
 331   if (!joinable)
 332     posix_check_cmd (pthread_detach (thread));
 333 #endif /* G_THREADS_IMPL_DCE */
 334 }
 335
 336 static void
 337 g_thread_yield_posix_impl (void)
 338 {
 339   POSIX_YIELD_FUNC;
 340 }
 341
 342 static void
 343 g_thread_join_posix_impl (gpointer thread)
 344 {
 345   gpointer ignore;
 346   posix_check_cmd (pthread_join (*(pthread_t*)thread, &ignore));
 347 }
 348
 349 static void
 350 g_thread_exit_posix_impl (void)
 351 {
 352   pthread_exit (NULL);
 353 }
 354
 355 static void
 356 g_thread_set_priority_posix_impl (gpointer thread, GThreadPriority priority)
 357 {
 358   g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW);
 359   g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT);
 360 #ifdef HAVE_PRIORITIES
 361 # ifdef G_THREADS_IMPL_POSIX
 362   {
 363     struct sched_param sched;
 364     int policy;
 365     posix_check_cmd (pthread_getschedparam (*(pthread_t*)thread, &policy,
 366                                             &sched));
 367     sched.sched_priority = g_thread_priority_map [priority];
 368     posix_check_cmd_prio (pthread_setschedparam (*(pthread_t*)thread, policy,
 369                                                  &sched));
 370   }
 371 # else /* G_THREADS_IMPL_DCE */
 372   posix_check_cmd_prio (pthread_setprio (*(pthread_t*)thread,
 373                                          g_thread_priority_map [priority]));
 374 # endif
 375 #endif /* HAVE_PRIORITIES */
 376 }
 377
 378 static void
 379 g_thread_self_posix_impl (gpointer thread)
 380 {
 381   *(pthread_t*)thread = pthread_self();
 382 }
 383
 384 static GThreadFunctions g_thread_functions_for_glib_use_default =
 385 {
 386   g_mutex_new_posix_impl,
 387   (void (*)(GMutex *)) pthread_mutex_lock,
 388   g_mutex_trylock_posix_impl,
 389   (void (*)(GMutex *)) pthread_mutex_unlock,
 390   g_mutex_free_posix_impl,
 391   g_cond_new_posix_impl,
 392   (void (*)(GCond *)) pthread_cond_signal,
 393   (void (*)(GCond *)) pthread_cond_broadcast,
 394   (void (*)(GCond *, GMutex *)) pthread_cond_wait,
 395   g_cond_timed_wait_posix_impl,
 396   g_cond_free_posix_impl,
 397   g_private_new_posix_impl,
 398   g_private_get_posix_impl,
 399   g_private_set_posix_impl,
 400   g_thread_create_posix_impl,
 401   g_thread_yield_posix_impl,
 402   g_thread_join_posix_impl,
 403   g_thread_exit_posix_impl,
 404   g_thread_set_priority_posix_impl,
 405   g_thread_self_posix_impl
 406 };