glib/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 "config.h"
  35
  36 #include "glib.h"
  37 #include "gthreadprivate.h"
  38
  39 #include <pthread.h>
  40 #include <errno.h>
  41 #include <stdlib.h>
  42 #ifdef HAVE_SYS_TIME_H
  43 # include <sys/time.h>
  44 #endif
  45 #ifdef HAVE_UNISTD_H
  46 # include <unistd.h>
  47 #endif
  48
  49 #ifdef HAVE_SCHED_H
  50 #include <sched.h>
  51 #endif
  52
  53 #define posix_check_err(err, name) G_STMT_START{                        \
  54   int error = (err);                                                    \
  55   if (error)                                                            \
  56     g_error ("file %s: line %d (%s): error '%s' during '%s'",           \
  57            __FILE__, __LINE__, G_STRFUNC,                               \
  58            g_strerror (error), name);                                   \
  59   }G_STMT_END
  60
  61 #define posix_check_cmd(cmd) posix_check_err (cmd, #cmd)
  62
  63 #ifdef G_ENABLE_DEBUG
  64 static gboolean posix_check_cmd_prio_warned = FALSE;
  65 # define posix_check_cmd_prio(cmd) G_STMT_START{                        \
  66     int err = (cmd);                                                    \
  67     if (err == EPERM)                                                   \
  68       {                                                                 \
  69         if (!posix_check_cmd_prio_warned)                               \
  70           {                                                             \
  71             posix_check_cmd_prio_warned = TRUE;                         \
  72             g_warning ("Priorities can only be changed "                \
  73                         "(resp. increased) by root.");                  \
  74           }                                                             \
  75       }                                                                 \
  76     else                                                                \
  77       posix_check_err (err, #cmd);                                      \
  78      }G_STMT_END
  79 #else /* G_ENABLE_DEBUG */
  80 # define posix_check_cmd_prio(cmd) G_STMT_START{                        \
  81     int err = (cmd);                                                    \
  82     if (err != EPERM)                                                   \
  83       posix_check_err (err, #cmd);                                      \
  84      }G_STMT_END
  85 #endif /* G_ENABLE_DEBUG */
  86
  87 #if defined (POSIX_MIN_PRIORITY) && defined (POSIX_MAX_PRIORITY)
  88 # define HAVE_PRIORITIES 1
  89 static gint priority_normal_value;
  90 # ifdef __FreeBSD__
  91    /* FreeBSD threads use different priority values from the POSIX_
  92     * defines so we just set them here. The corresponding macros
  93     * PTHREAD_MIN_PRIORITY and PTHREAD_MAX_PRIORITY are implied to be
  94     * exported by the docs, but they aren't.
  95     */
  96 #  define PRIORITY_LOW_VALUE      0
  97 #  define PRIORITY_URGENT_VALUE   31
  98 # else /* !__FreeBSD__ */
  99 #  define PRIORITY_LOW_VALUE      POSIX_MIN_PRIORITY
 100 #  define PRIORITY_URGENT_VALUE   POSIX_MAX_PRIORITY
 101 # endif /* !__FreeBSD__ */
 102 # define PRIORITY_NORMAL_VALUE    priority_normal_value
 103
 104 # define PRIORITY_HIGH_VALUE \
 105     ((PRIORITY_NORMAL_VALUE + PRIORITY_URGENT_VALUE * 2) / 3)
 106
 107 static gint
 108 g_thread_priority_map (GThreadPriority priority)
 109 {
 110   switch (priority)
 111     {
 112     case G_THREAD_PRIORITY_LOW:
 113       return PRIORITY_LOW_VALUE;
 114
 115     case G_THREAD_PRIORITY_NORMAL:
 116       return PRIORITY_NORMAL_VALUE;
 117
 118     case G_THREAD_PRIORITY_HIGH:
 119       return PRIORITY_HIGH_VALUE;
 120
 121     case G_THREAD_PRIORITY_URGENT:
 122       return PRIORITY_URGENT_VALUE;
 123
 124     default:
 125       g_assert_not_reached ();
 126     }
 127 }
 128
 129 #endif /* POSIX_MIN_PRIORITY && POSIX_MAX_PRIORITY */
 130
 131 static gulong g_thread_min_stack_size = 0;
 132
 133 #define G_MUTEX_SIZE (sizeof (pthread_mutex_t))
 134
 135 void
 136 _g_thread_impl_init(void)
 137 {
 138 #ifdef _SC_THREAD_STACK_MIN
 139   g_thread_min_stack_size = MAX (sysconf (_SC_THREAD_STACK_MIN), 0);
 140 #endif /* _SC_THREAD_STACK_MIN */
 141 #ifdef HAVE_PRIORITIES
 142   {
 143     struct sched_param sched;
 144     int policy;
 145     posix_check_cmd (pthread_getschedparam (pthread_self(), &policy, &sched));
 146     priority_normal_value = sched.sched_priority;
 147   }
 148 #endif /* HAVE_PRIORITIES */
 149 }
 150
 151 static GMutex *
 152 g_mutex_new_posix_impl (void)
 153 {
 154   GMutex *result = (GMutex *) g_new (pthread_mutex_t, 1);
 155   posix_check_cmd (pthread_mutex_init ((pthread_mutex_t *) result, NULL));
 156   return result;
 157 }
 158
 159 static void
 160 g_mutex_free_posix_impl (GMutex * mutex)
 161 {
 162   posix_check_cmd (pthread_mutex_destroy ((pthread_mutex_t *) mutex));
 163   g_free (mutex);
 164 }
 165
 166 /* NOTE: the functions g_mutex_lock and g_mutex_unlock may not use
 167    functions from gmem.c and gmessages.c; */
 168
 169 /* pthread_mutex_lock, pthread_mutex_unlock can be taken directly, as
 170    signature and semantic are right, but without error check then!!!!,
 171    we might want to change this therefore. */
 172
 173 static gboolean
 174 g_mutex_trylock_posix_impl (GMutex * mutex)
 175 {
 176   int result;
 177
 178   result = pthread_mutex_trylock ((pthread_mutex_t *) mutex);
 179
 180   if (result == EBUSY)
 181     return FALSE;
 182
 183   posix_check_err (result, "pthread_mutex_trylock");
 184   return TRUE;
 185 }
 186
 187 static GCond *
 188 g_cond_new_posix_impl (void)
 189 {
 190   GCond *result = (GCond *) g_new (pthread_cond_t, 1);
 191   posix_check_cmd (pthread_cond_init ((pthread_cond_t *) result, NULL));
 192   return result;
 193 }
 194
 195 /* pthread_cond_signal, pthread_cond_broadcast and pthread_cond_wait
 196    can be taken directly, as signature and semantic are right, but
 197    without error check then!!!!, we might want to change this
 198    therefore. */
 199
 200 #define G_NSEC_PER_SEC 1000000000
 201
 202 static gboolean
 203 g_cond_timed_wait_posix_impl (GCond * cond,
 204                               GMutex * entered_mutex,
 205                               GTimeVal * abs_time)
 206 {
 207   int result;
 208   struct timespec end_time;
 209   gboolean timed_out;
 210
 211   g_return_val_if_fail (cond != NULL, FALSE);
 212   g_return_val_if_fail (entered_mutex != NULL, FALSE);
 213
 214   if (!abs_time)
 215     {
 216       result = pthread_cond_wait ((pthread_cond_t *)cond,
 217                                   (pthread_mutex_t *) entered_mutex);
 218       timed_out = FALSE;
 219     }
 220   else
 221     {
 222       end_time.tv_sec = abs_time->tv_sec;
 223       end_time.tv_nsec = abs_time->tv_usec * (G_NSEC_PER_SEC / G_USEC_PER_SEC);
 224
 225       g_return_val_if_fail (end_time.tv_nsec < G_NSEC_PER_SEC, TRUE);
 226
 227       result = pthread_cond_timedwait ((pthread_cond_t *) cond,
 228                                        (pthread_mutex_t *) entered_mutex,
 229                                        &end_time);
 230       timed_out = (result == ETIMEDOUT);
 231     }
 232
 233   if (!timed_out)
 234     posix_check_err (result, "pthread_cond_timedwait");
 235
 236   return !timed_out;
 237 }
 238
 239 static void
 240 g_cond_free_posix_impl (GCond * cond)
 241 {
 242   posix_check_cmd (pthread_cond_destroy ((pthread_cond_t *) cond));
 243   g_free (cond);
 244 }
 245
 246 static GPrivate *
 247 g_private_new_posix_impl (GDestroyNotify destructor)
 248 {
 249   GPrivate *result = (GPrivate *) g_new (pthread_key_t, 1);
 250   posix_check_cmd (pthread_key_create ((pthread_key_t *) result, destructor));
 251   return result;
 252 }
 253
 254 /* NOTE: the functions g_private_get and g_private_set may not use
 255    functions from gmem.c and gmessages.c */
 256
 257 static void
 258 g_private_set_posix_impl (GPrivate * private_key, gpointer value)
 259 {
 260   if (!private_key)
 261     return;
 262   pthread_setspecific (*(pthread_key_t *) private_key, value);
 263 }
 264
 265 static gpointer
 266 g_private_get_posix_impl (GPrivate * private_key)
 267 {
 268   if (!private_key)
 269     return NULL;
 270
 271   return pthread_getspecific (*(pthread_key_t *) private_key);
 272 }
 273
 274 static void
 275 g_thread_create_posix_impl (GThreadFunc thread_func,
 276                             gpointer arg,
 277                             gulong stack_size,
 278                             gboolean joinable,
 279                             gboolean bound,
 280                             GThreadPriority priority,
 281                             gpointer thread,
 282                             GError **error)
 283 {
 284   pthread_attr_t attr;
 285   gint ret;
 286
 287   g_return_if_fail (thread_func);
 288   g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW);
 289   g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT);
 290
 291   posix_check_cmd (pthread_attr_init (&attr));
 292
 293 #ifdef HAVE_PTHREAD_ATTR_SETSTACKSIZE
 294   if (stack_size)
 295     {
 296       stack_size = MAX (g_thread_min_stack_size, stack_size);
 297       /* No error check here, because some systems can't do it and
 298        * we simply don't want threads to fail because of that. */
 299       pthread_attr_setstacksize (&attr, stack_size);
 300     }
 301 #endif /* HAVE_PTHREAD_ATTR_SETSTACKSIZE */
 302
 303 #ifdef PTHREAD_SCOPE_SYSTEM
 304   if (bound)
 305     /* No error check here, because some systems can't do it and we
 306      * simply don't want threads to fail because of that. */
 307     pthread_attr_setscope (&attr, PTHREAD_SCOPE_SYSTEM);
 308 #endif /* PTHREAD_SCOPE_SYSTEM */
 309
 310   posix_check_cmd (pthread_attr_setdetachstate (&attr,
 311           joinable ? PTHREAD_CREATE_JOINABLE : PTHREAD_CREATE_DETACHED));
 312
 313 #ifdef HAVE_PRIORITIES
 314   {
 315     struct sched_param sched;
 316     posix_check_cmd (pthread_attr_getschedparam (&attr, &sched));
 317     sched.sched_priority = g_thread_priority_map (priority);
 318     posix_check_cmd_prio (pthread_attr_setschedparam (&attr, &sched));
 319   }
 320 #endif /* HAVE_PRIORITIES */
 321   ret = pthread_create (thread, &attr, (void* (*)(void*))thread_func, arg);
 322
 323   posix_check_cmd (pthread_attr_destroy (&attr));
 324
 325   if (ret == EAGAIN)
 326     {
 327       g_set_error (error, G_THREAD_ERROR, G_THREAD_ERROR_AGAIN,
 328                    "Error creating thread: %s", g_strerror (ret));
 329       return;
 330     }
 331
 332   posix_check_err (ret, "pthread_create");
 333 }
 334
 335 static void
 336 g_thread_yield_posix_impl (void)
 337 {
 338   POSIX_YIELD_FUNC;
 339 }
 340
 341 static void
 342 g_thread_join_posix_impl (gpointer thread)
 343 {
 344   gpointer ignore;
 345   posix_check_cmd (pthread_join (*(pthread_t*)thread, &ignore));
 346 }
 347
 348 static void
 349 g_thread_exit_posix_impl (void)
 350 {
 351   pthread_exit (NULL);
 352 }
 353
 354 static void
 355 g_thread_set_priority_posix_impl (gpointer thread, GThreadPriority priority)
 356 {
 357   g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW);
 358   g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT);
 359 #ifdef HAVE_PRIORITIES
 360   {
 361     struct sched_param sched;
 362     int policy;
 363     posix_check_cmd (pthread_getschedparam (*(pthread_t*)thread, &policy,
 364                                             &sched));
 365     sched.sched_priority = g_thread_priority_map (priority);
 366     posix_check_cmd_prio (pthread_setschedparam (*(pthread_t*)thread, policy,
 367                                                  &sched));
 368   }
 369 #endif /* HAVE_PRIORITIES */
 370 }
 371
 372 static void
 373 g_thread_self_posix_impl (gpointer thread)
 374 {
 375   *(pthread_t*)thread = pthread_self();
 376 }
 377
 378 static gboolean
 379 g_thread_equal_posix_impl (gpointer thread1, gpointer thread2)
 380 {
 381   return (pthread_equal (*(pthread_t*)thread1, *(pthread_t*)thread2) != 0);
 382 }
 383
 384 GThreadFunctions g_thread_functions_for_glib_use =
 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   g_thread_equal_posix_impl
 407 };