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 <pthread.h>
37#include <errno.h>
38#include <stdlib.h>
39#ifdef HAVE_SYS_TIME_H
40# include <sys/time.h>
41#endif
42#ifdef HAVE_UNISTD_H
43# include <unistd.h>
44#endif
45
46#ifdef HAVE_SCHED_H
47#include <sched.h>
48#endif
49
50#define posix_check_err(err, name) G_STMT_START{			\
51  int error = (err); 							\
52  if (error)	 		 		 			\
53    g_error ("file %s: line %d (%s): error '%s' during '%s'",		\
54           __FILE__, __LINE__, G_STRFUNC,				\
55           g_strerror (error), name);					\
56  }G_STMT_END
57
58#define posix_check_cmd(cmd) posix_check_err (posix_error (cmd), #cmd)
59
60#ifdef G_ENABLE_DEBUG
61static gboolean posix_check_cmd_prio_warned = FALSE;
62# define posix_check_cmd_prio(cmd) G_STMT_START{			\
63    int err = posix_error (cmd);					\
64    if (err == EPERM)		 		 			\
65      { 	 			 				\
66        if (!posix_check_cmd_prio_warned) 		 		\
67          { 	 				 			\
68            posix_check_cmd_prio_warned = TRUE;		 		\
69            g_warning ("Priorities can only be changed " 		\
70                        "(resp. increased) by root."); 			\
71          }			 					\
72      }			 						\
73    else  		 						\
74      posix_check_err (err, #cmd);					\
75     }G_STMT_END
76#else /* G_ENABLE_DEBUG */
77# define posix_check_cmd_prio(cmd) G_STMT_START{			\
78    int err = posix_error (cmd);					\
79    if (err != EPERM)		 		 			\
80      posix_check_err (err, #cmd);					\
81     }G_STMT_END
82#endif /* G_ENABLE_DEBUG */
83
84#if defined(G_THREADS_IMPL_POSIX)
85# define posix_error(what) (what)
86# define mutexattr_default NULL
87# define condattr_default NULL
88#elif defined(G_THREADS_IMPL_DCE)
89# define posix_error(what) ((what) == -1 ? errno : 0)
90# define pthread_key_create(a, b) pthread_keycreate (a, b)
91# define pthread_attr_init(a) pthread_attr_create (a)
92# define pthread_attr_destroy(a) pthread_attr_delete (a)
93# define pthread_create(a, b, c, d) pthread_create (a, *b, c, d)
94# define mutexattr_default (pthread_mutexattr_default)
95# define condattr_default (pthread_condattr_default)
96#else /* neither G_THREADS_IMPL_POSIX nor G_THREADS_IMPL_DCE are defined */
97# error This should not happen. Contact the GLib team.
98#endif
99
100#if defined (POSIX_MIN_PRIORITY) && defined (POSIX_MAX_PRIORITY)
101# define HAVE_PRIORITIES 1
102static gint priority_normal_value;
103# ifdef __FreeBSD__
104   /* FreeBSD threads use different priority values from the POSIX_
105    * defines so we just set them here. The corresponding macros
106    * PTHREAD_MIN_PRIORITY and PTHREAD_MAX_PRIORITY are implied to be
107    * exported by the docs, but they aren't.
108    */
109#  define PRIORITY_LOW_VALUE      0
110#  define PRIORITY_URGENT_VALUE   31
111# else /* !__FreeBSD__ */
112#  define PRIORITY_LOW_VALUE      POSIX_MIN_PRIORITY
113#  define PRIORITY_URGENT_VALUE   POSIX_MAX_PRIORITY
114# endif /* !__FreeBSD__ */
115# define PRIORITY_NORMAL_VALUE    priority_normal_value
116#endif /* POSIX_MIN_PRIORITY && POSIX_MAX_PRIORITY */
117
118static gulong g_thread_min_stack_size = 0;
119
120#define G_MUTEX_SIZE (sizeof (pthread_mutex_t))
121
122#if defined(HAVE_CLOCK_GETTIME) && defined(HAVE_MONOTONIC_CLOCK)
123#define USE_CLOCK_GETTIME 1
124static gint posix_clock = 0;
125#endif
126
127#if defined(_SC_THREAD_STACK_MIN) || defined (HAVE_PRIORITIES) || defined (USE_CLOCK_GETTIME)
128#define HAVE_G_THREAD_IMPL_INIT
129static void
130g_thread_impl_init(void)
131{
132#ifdef _SC_THREAD_STACK_MIN
133  g_thread_min_stack_size = MAX (sysconf (_SC_THREAD_STACK_MIN), 0);
134#endif /* _SC_THREAD_STACK_MIN */
135#ifdef HAVE_PRIORITIES
136# ifdef G_THREADS_IMPL_POSIX
137  {
138    struct sched_param sched;
139    int policy;
140    posix_check_cmd (pthread_getschedparam (pthread_self(), &policy, &sched));
141    priority_normal_value = sched.sched_priority;
142  }
143# else /* G_THREADS_IMPL_DCE */
144  posix_check_cmd (priority_normal_value =
145		   pthread_getprio (*(pthread_t*)thread,
146				    g_thread_priority_map [priority]));
147# endif
148#endif /* HAVE_PRIORITIES */
149
150#ifdef USE_CLOCK_GETTIME
151 if (sysconf (_SC_MONOTONIC_CLOCK) >= 0)
152   posix_clock = CLOCK_MONOTONIC;
153 else
154   posix_clock = CLOCK_REALTIME;
155#endif
156}
157#endif /* _SC_THREAD_STACK_MIN || HAVE_PRIORITIES */
158
159static GMutex *
160g_mutex_new_posix_impl (void)
161{
162  GMutex *result = (GMutex *) g_new (pthread_mutex_t, 1);
163  posix_check_cmd (pthread_mutex_init ((pthread_mutex_t *) result,
164				       mutexattr_default));
165  return result;
166}
167
168static void
169g_mutex_free_posix_impl (GMutex * mutex)
170{
171  posix_check_cmd (pthread_mutex_destroy ((pthread_mutex_t *) mutex));
172  g_free (mutex);
173}
174
175/* NOTE: the functions g_mutex_lock and g_mutex_unlock may not use
176   functions from gmem.c and gmessages.c; */
177
178/* pthread_mutex_lock, pthread_mutex_unlock can be taken directly, as
179   signature and semantic are right, but without error check then!!!!,
180   we might want to change this therefore. */
181
182static gboolean
183g_mutex_trylock_posix_impl (GMutex * mutex)
184{
185  int result;
186
187  result = pthread_mutex_trylock ((pthread_mutex_t *) mutex);
188
189#ifdef G_THREADS_IMPL_POSIX
190  if (result == EBUSY)
191    return FALSE;
192#else /* G_THREADS_IMPL_DCE */
193  if (result == 0)
194    return FALSE;
195#endif
196
197  posix_check_err (posix_error (result), "pthread_mutex_trylock");
198  return TRUE;
199}
200
201static GCond *
202g_cond_new_posix_impl (void)
203{
204  GCond *result = (GCond *) g_new (pthread_cond_t, 1);
205  posix_check_cmd (pthread_cond_init ((pthread_cond_t *) result,
206				      condattr_default));
207  return result;
208}
209
210/* pthread_cond_signal, pthread_cond_broadcast and pthread_cond_wait
211   can be taken directly, as signature and semantic are right, but
212   without error check then!!!!, we might want to change this
213   therefore. */
214
215#define G_NSEC_PER_SEC 1000000000
216
217static gboolean
218g_cond_timed_wait_posix_impl (GCond * cond,
219			      GMutex * entered_mutex,
220			      GTimeVal * abs_time)
221{
222  int result;
223  struct timespec end_time;
224  gboolean timed_out;
225
226  g_return_val_if_fail (cond != NULL, FALSE);
227  g_return_val_if_fail (entered_mutex != NULL, FALSE);
228
229  if (!abs_time)
230    {
231      result = pthread_cond_wait ((pthread_cond_t *)cond,
232                                  (pthread_mutex_t *) entered_mutex);
233      timed_out = FALSE;
234    }
235  else
236    {
237      end_time.tv_sec = abs_time->tv_sec;
238      end_time.tv_nsec = abs_time->tv_usec * (G_NSEC_PER_SEC / G_USEC_PER_SEC);
239
240      g_return_val_if_fail (end_time.tv_nsec < G_NSEC_PER_SEC, TRUE);
241
242      result = pthread_cond_timedwait ((pthread_cond_t *) cond,
243                                       (pthread_mutex_t *) entered_mutex,
244                                       &end_time);
245#ifdef G_THREADS_IMPL_POSIX
246      timed_out = (result == ETIMEDOUT);
247#else /* G_THREADS_IMPL_DCE */
248      timed_out = (result == -1) && (errno == EAGAIN);
249#endif
250    }
251
252  if (!timed_out)
253    posix_check_err (posix_error (result), "pthread_cond_timedwait");
254
255  return !timed_out;
256}
257
258static void
259g_cond_free_posix_impl (GCond * cond)
260{
261  posix_check_cmd (pthread_cond_destroy ((pthread_cond_t *) cond));
262  g_free (cond);
263}
264
265static GPrivate *
266g_private_new_posix_impl (GDestroyNotify destructor)
267{
268  GPrivate *result = (GPrivate *) g_new (pthread_key_t, 1);
269  posix_check_cmd (pthread_key_create ((pthread_key_t *) result, destructor));
270  return result;
271}
272
273/* NOTE: the functions g_private_get and g_private_set may not use
274   functions from gmem.c and gmessages.c */
275
276static void
277g_private_set_posix_impl (GPrivate * private_key, gpointer value)
278{
279  if (!private_key)
280    return;
281  pthread_setspecific (*(pthread_key_t *) private_key, value);
282}
283
284static gpointer
285g_private_get_posix_impl (GPrivate * private_key)
286{
287  if (!private_key)
288    return NULL;
289#ifdef G_THREADS_IMPL_POSIX
290  return pthread_getspecific (*(pthread_key_t *) private_key);
291#else /* G_THREADS_IMPL_DCE */
292  {
293    void* data;
294    posix_check_cmd (pthread_getspecific (*(pthread_key_t *) private_key,
295					  &data));
296    return data;
297  }
298#endif
299}
300
301static void
302g_thread_create_posix_impl (GThreadFunc thread_func,
303			    gpointer arg,
304			    gulong stack_size,
305			    gboolean joinable,
306			    gboolean bound,
307			    GThreadPriority priority,
308			    gpointer thread,
309			    GError **error)
310{
311  pthread_attr_t attr;
312  gint ret;
313
314  g_return_if_fail (thread_func);
315  g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW);
316  g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT);
317
318  posix_check_cmd (pthread_attr_init (&attr));
319
320#ifdef HAVE_PTHREAD_ATTR_SETSTACKSIZE
321  if (stack_size)
322    {
323      stack_size = MAX (g_thread_min_stack_size, stack_size);
324      /* No error check here, because some systems can't do it and
325       * we simply don't want threads to fail because of that. */
326      pthread_attr_setstacksize (&attr, stack_size);
327    }
328#endif /* HAVE_PTHREAD_ATTR_SETSTACKSIZE */
329
330#ifdef PTHREAD_SCOPE_SYSTEM
331  if (bound)
332    /* No error check here, because some systems can't do it and we
333     * simply don't want threads to fail because of that. */
334    pthread_attr_setscope (&attr, PTHREAD_SCOPE_SYSTEM);
335#endif /* PTHREAD_SCOPE_SYSTEM */
336
337#ifdef G_THREADS_IMPL_POSIX
338  posix_check_cmd (pthread_attr_setdetachstate (&attr,
339          joinable ? PTHREAD_CREATE_JOINABLE : PTHREAD_CREATE_DETACHED));
340#endif /* G_THREADS_IMPL_POSIX */
341
342#ifdef HAVE_PRIORITIES
343# ifdef G_THREADS_IMPL_POSIX
344  {
345    struct sched_param sched;
346    posix_check_cmd (pthread_attr_getschedparam (&attr, &sched));
347    sched.sched_priority = g_thread_priority_map [priority];
348    posix_check_cmd_prio (pthread_attr_setschedparam (&attr, &sched));
349  }
350# else /* G_THREADS_IMPL_DCE */
351  posix_check_cmd_prio
352    (pthread_attr_setprio (&attr, g_thread_priority_map [priority]));
353# endif /* G_THREADS_IMPL_DCE */
354#endif /* HAVE_PRIORITIES */
355  ret = posix_error (pthread_create (thread, &attr,
356				     (void* (*)(void*))thread_func, arg));
357
358  posix_check_cmd (pthread_attr_destroy (&attr));
359
360  if (ret == EAGAIN)
361    {
362      g_set_error (error, G_THREAD_ERROR, G_THREAD_ERROR_AGAIN,
363		   "Error creating thread: %s", g_strerror (ret));
364      return;
365    }
366
367  posix_check_err (ret, "pthread_create");
368
369#ifdef G_THREADS_IMPL_DCE
370  if (!joinable)
371    posix_check_cmd (pthread_detach (thread));
372#endif /* G_THREADS_IMPL_DCE */
373}
374
375static void
376g_thread_yield_posix_impl (void)
377{
378  POSIX_YIELD_FUNC;
379}
380
381static void
382g_thread_join_posix_impl (gpointer thread)
383{
384  gpointer ignore;
385  posix_check_cmd (pthread_join (*(pthread_t*)thread, &ignore));
386}
387
388static void
389g_thread_exit_posix_impl (void)
390{
391  pthread_exit (NULL);
392}
393
394static void
395g_thread_set_priority_posix_impl (gpointer thread, GThreadPriority priority)
396{
397  g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW);
398  g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT);
399#ifdef HAVE_PRIORITIES
400# ifdef G_THREADS_IMPL_POSIX
401  {
402    struct sched_param sched;
403    int policy;
404    posix_check_cmd (pthread_getschedparam (*(pthread_t*)thread, &policy,
405					    &sched));
406    sched.sched_priority = g_thread_priority_map [priority];
407    posix_check_cmd_prio (pthread_setschedparam (*(pthread_t*)thread, policy,
408						 &sched));
409  }
410# else /* G_THREADS_IMPL_DCE */
411  posix_check_cmd_prio (pthread_setprio (*(pthread_t*)thread,
412					 g_thread_priority_map [priority]));
413# endif
414#endif /* HAVE_PRIORITIES */
415}
416
417static void
418g_thread_self_posix_impl (gpointer thread)
419{
420  *(pthread_t*)thread = pthread_self();
421}
422
423static gboolean
424g_thread_equal_posix_impl (gpointer thread1, gpointer thread2)
425{
426  return (pthread_equal (*(pthread_t*)thread1, *(pthread_t*)thread2) != 0);
427}
428
429#ifdef USE_CLOCK_GETTIME
430static guint64
431gettime (void)
432{
433  struct timespec tv;
434
435  clock_gettime (posix_clock, &tv);
436
437  return (guint64) tv.tv_sec * G_NSEC_PER_SEC + tv.tv_nsec;
438}
439static guint64 (*g_thread_gettime_impl)(void) = gettime;
440#else
441static guint64 (*g_thread_gettime_impl)(void) = 0;
442#endif
443
444static GThreadFunctions g_thread_functions_for_glib_use_default =
445{
446  g_mutex_new_posix_impl,
447  (void (*)(GMutex *)) pthread_mutex_lock,
448  g_mutex_trylock_posix_impl,
449  (void (*)(GMutex *)) pthread_mutex_unlock,
450  g_mutex_free_posix_impl,
451  g_cond_new_posix_impl,
452  (void (*)(GCond *)) pthread_cond_signal,
453  (void (*)(GCond *)) pthread_cond_broadcast,
454  (void (*)(GCond *, GMutex *)) pthread_cond_wait,
455  g_cond_timed_wait_posix_impl,
456  g_cond_free_posix_impl,
457  g_private_new_posix_impl,
458  g_private_get_posix_impl,
459  g_private_set_posix_impl,
460  g_thread_create_posix_impl,
461  g_thread_yield_posix_impl,
462  g_thread_join_posix_impl,
463  g_thread_exit_posix_impl,
464  g_thread_set_priority_posix_impl,
465  g_thread_self_posix_impl,
466  g_thread_equal_posix_impl
467};
468