--- /dev/null
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+/* dbus-sysdeps-pthread.c Implements threads using pthreads (internal to libdbus)
+ *
+ * Copyright (C) 2002, 2003, 2006 Red Hat, Inc.
+ *
+ * Licensed under the Academic Free License version 2.1
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include "dbus-internals.h"
+#include "dbus-sysdeps.h"
+#include "dbus-threads.h"
+
+#include <sys/time.h>
+#include <pthread.h>
+#include <string.h>
+
+#ifdef HAVE_ERRNO_H
+#include <errno.h>
+#endif
+
+typedef struct {
+ pthread_mutex_t lock; /**< lock protecting count field */
+ volatile int count; /**< count of how many times lock holder has recursively locked */
+ volatile pthread_t holder; /**< holder of the lock if count >0,
+ valid but arbitrary thread if count
+ has ever been >0, uninitialized memory
+ if count has never been >0 */
+} DBusMutexPThread;
+
+typedef struct {
+ pthread_cond_t cond; /**< the condition */
+} DBusCondVarPThread;
+
+#define DBUS_MUTEX(m) ((DBusMutex*) m)
+#define DBUS_MUTEX_PTHREAD(m) ((DBusMutexPThread*) m)
+
+#define DBUS_COND_VAR(c) ((DBusCondVar*) c)
+#define DBUS_COND_VAR_PTHREAD(c) ((DBusCondVarPThread*) c)
+
+
+#ifdef DBUS_DISABLE_ASSERT
+/* (tmp != 0) is a no-op usage to silence compiler */
+#define PTHREAD_CHECK(func_name, result_or_call) \
+ do { int tmp = (result_or_call); if (tmp != 0) {;} } while (0)
+#else
+#define PTHREAD_CHECK(func_name, result_or_call) do { \
+ int tmp = (result_or_call); \
+ if (tmp != 0) { \
+ _dbus_warn_check_failed ("pthread function %s failed with %d %s in %s\n", \
+ func_name, tmp, strerror(tmp), _DBUS_FUNCTION_NAME); \
+ } \
+} while (0)
+#endif /* !DBUS_DISABLE_ASSERT */
+
+static DBusMutex*
+_dbus_pthread_mutex_new (void)
+{
+ DBusMutexPThread *pmutex;
+ int result;
+
+ pmutex = dbus_new (DBusMutexPThread, 1);
+ if (pmutex == NULL)
+ return NULL;
+
+ result = pthread_mutex_init (&pmutex->lock, NULL);
+
+ if (result == ENOMEM || result == EAGAIN)
+ {
+ dbus_free (pmutex);
+ return NULL;
+ }
+ else
+ {
+ PTHREAD_CHECK ("pthread_mutex_init", result);
+ }
+
+ /* Only written */
+ pmutex->count = 0;
+
+ /* There's no portable way to have a "null" pthread afaik so we
+ * can't set pmutex->holder to anything sensible. We only access it
+ * once the lock is held (which means we've set it).
+ */
+
+ return DBUS_MUTEX (pmutex);
+}
+
+static void
+_dbus_pthread_mutex_free (DBusMutex *mutex)
+{
+ DBusMutexPThread *pmutex = DBUS_MUTEX_PTHREAD (mutex);
+
+ _dbus_assert (pmutex->count == 0);
+
+ PTHREAD_CHECK ("pthread_mutex_destroy", pthread_mutex_destroy (&pmutex->lock));
+
+ dbus_free (pmutex);
+}
+
+static void
+_dbus_pthread_mutex_lock (DBusMutex *mutex)
+{
+ DBusMutexPThread *pmutex = DBUS_MUTEX_PTHREAD (mutex);
+ pthread_t self = pthread_self ();
+
+ /* If the count is > 0 then someone had the lock, maybe us. If it is
+ * 0, then it might immediately change right after we read it,
+ * but it will be changed by another thread; i.e. if we read 0,
+ * we assume that this thread doesn't have the lock.
+ *
+ * Not 100% sure this is safe, but ... seems like it should be.
+ */
+ if (pmutex->count == 0)
+ {
+ /* We know we don't have the lock; someone may have the lock. */
+
+ PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&pmutex->lock));
+
+ /* We now have the lock. Count must be 0 since it must be 0 when
+ * the lock is released by another thread, and we just now got
+ * the lock.
+ */
+ _dbus_assert (pmutex->count == 0);
+
+ pmutex->holder = self;
+ pmutex->count = 1;
+ }
+ else
+ {
+ /* We know someone had the lock, possibly us. Thus
+ * pmutex->holder is not pointing to junk, though it may not be
+ * the lock holder anymore if the lock holder is not us. If the
+ * lock holder is us, then we definitely have the lock.
+ */
+
+ if (pthread_equal (pmutex->holder, self))
+ {
+ /* We already have the lock. */
+ _dbus_assert (pmutex->count > 0);
+ }
+ else
+ {
+ /* Wait for the lock */
+ PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&pmutex->lock));
+ pmutex->holder = self;
+ _dbus_assert (pmutex->count == 0);
+ }
+
+ pmutex->count += 1;
+ }
+}
+
+static void
+_dbus_pthread_mutex_unlock (DBusMutex *mutex)
+{
+ DBusMutexPThread *pmutex = DBUS_MUTEX_PTHREAD (mutex);
+
+ _dbus_assert (pmutex->count > 0);
+
+ pmutex->count -= 1;
+
+ if (pmutex->count == 0)
+ PTHREAD_CHECK ("pthread_mutex_unlock", pthread_mutex_unlock (&pmutex->lock));
+
+ /* We leave pmutex->holder set to ourselves, its content is undefined if count is 0 */
+}
+
+static DBusCondVar *
+_dbus_pthread_condvar_new (void)
+{
+ DBusCondVarPThread *pcond;
+ int result;
+
+ pcond = dbus_new (DBusCondVarPThread, 1);
+ if (pcond == NULL)
+ return NULL;
+
+ result = pthread_cond_init (&pcond->cond, NULL);
+
+ if (result == EAGAIN || result == ENOMEM)
+ {
+ dbus_free (pcond);
+ return NULL;
+ }
+ else
+ {
+ PTHREAD_CHECK ("pthread_cond_init", result);
+ }
+
+ return DBUS_COND_VAR (pcond);
+}
+
+static void
+_dbus_pthread_condvar_free (DBusCondVar *cond)
+{
+ DBusCondVarPThread *pcond = DBUS_COND_VAR_PTHREAD (cond);
+
+ PTHREAD_CHECK ("pthread_cond_destroy", pthread_cond_destroy (&pcond->cond));
+
+ dbus_free (pcond);
+}
+
+static void
+_dbus_pthread_condvar_wait (DBusCondVar *cond,
+ DBusMutex *mutex)
+{
+ DBusMutexPThread *pmutex = DBUS_MUTEX_PTHREAD (mutex);
+ DBusCondVarPThread *pcond = DBUS_COND_VAR_PTHREAD (cond);
+ int old_count;
+
+ _dbus_assert (pmutex->count > 0);
+ _dbus_assert (pthread_equal (pmutex->holder, pthread_self ()));
+
+ old_count = pmutex->count;
+ pmutex->count = 0; /* allow other threads to lock */
+ PTHREAD_CHECK ("pthread_cond_wait", pthread_cond_wait (&pcond->cond, &pmutex->lock));
+ _dbus_assert (pmutex->count == 0);
+ pmutex->count = old_count;
+ pmutex->holder = pthread_self(); /* other threads may have locked the mutex in the meantime */
+}
+
+static dbus_bool_t
+_dbus_pthread_condvar_wait_timeout (DBusCondVar *cond,
+ DBusMutex *mutex,
+ int timeout_milliseconds)
+{
+ DBusMutexPThread *pmutex = DBUS_MUTEX_PTHREAD (mutex);
+ DBusCondVarPThread *pcond = DBUS_COND_VAR_PTHREAD (cond);
+ struct timeval time_now;
+ struct timespec end_time;
+ int result;
+ int old_count;
+
+ _dbus_assert (pmutex->count > 0);
+ _dbus_assert (pthread_equal (pmutex->holder, pthread_self ()));
+
+ gettimeofday (&time_now, NULL);
+
+ end_time.tv_sec = time_now.tv_sec + timeout_milliseconds / 1000;
+ end_time.tv_nsec = (time_now.tv_usec + (timeout_milliseconds % 1000) * 1000) * 1000;
+ if (end_time.tv_nsec > 1000*1000*1000)
+ {
+ end_time.tv_sec += 1;
+ end_time.tv_nsec -= 1000*1000*1000;
+ }
+
+ old_count = pmutex->count;
+ pmutex->count = 0;
+ result = pthread_cond_timedwait (&pcond->cond, &pmutex->lock, &end_time);
+
+ if (result != ETIMEDOUT)
+ {
+ PTHREAD_CHECK ("pthread_cond_timedwait", result);
+ }
+
+ _dbus_assert (pmutex->count == 0);
+ pmutex->count = old_count;
+ pmutex->holder = pthread_self(); /* other threads may have locked the mutex in the meantime */
+
+ /* return true if we did not time out */
+ return result != ETIMEDOUT;
+}
+
+static void
+_dbus_pthread_condvar_wake_one (DBusCondVar *cond)
+{
+ DBusCondVarPThread *pcond = DBUS_COND_VAR_PTHREAD (cond);
+
+ PTHREAD_CHECK ("pthread_cond_signal", pthread_cond_signal (&pcond->cond));
+}
+
+static void
+_dbus_pthread_condvar_wake_all (DBusCondVar *cond)
+{
+ DBusCondVarPThread *pcond = DBUS_COND_VAR_PTHREAD (cond);
+
+ PTHREAD_CHECK ("pthread_cond_broadcast", pthread_cond_broadcast (&pcond->cond));
+}
+
+static const DBusThreadFunctions pthread_functions =
+{
+ DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_NEW_MASK |
+ DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_FREE_MASK |
+ DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_LOCK_MASK |
+ DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_UNLOCK_MASK |
+ DBUS_THREAD_FUNCTIONS_CONDVAR_NEW_MASK |
+ DBUS_THREAD_FUNCTIONS_CONDVAR_FREE_MASK |
+ DBUS_THREAD_FUNCTIONS_CONDVAR_WAIT_MASK |
+ DBUS_THREAD_FUNCTIONS_CONDVAR_WAIT_TIMEOUT_MASK |
+ DBUS_THREAD_FUNCTIONS_CONDVAR_WAKE_ONE_MASK|
+ DBUS_THREAD_FUNCTIONS_CONDVAR_WAKE_ALL_MASK,
+ NULL, NULL, NULL, NULL,
+ _dbus_pthread_condvar_new,
+ _dbus_pthread_condvar_free,
+ _dbus_pthread_condvar_wait,
+ _dbus_pthread_condvar_wait_timeout,
+ _dbus_pthread_condvar_wake_one,
+ _dbus_pthread_condvar_wake_all,
+ _dbus_pthread_mutex_new,
+ _dbus_pthread_mutex_free,
+ _dbus_pthread_mutex_lock,
+ _dbus_pthread_mutex_unlock
+};
+
+dbus_bool_t
+_dbus_threads_init_platform_specific (void)
+{
+ return dbus_threads_init (&pthread_functions);
+}
projects / monky / blobdiff