asterisk/include/asterisk/lock.h

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2006, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 * \brief General Asterisk channel locking definitions.
 *
 * - See \ref LockDef
 */

/* \page LockDef Asterisk thread locking models
 *
 * This file provides several different implementation of the functions,
 * depending on the platform, the use of DEBUG_THREADS, and the way
 * global mutexes are initialized.
 *
 * \par At the moment, we have 3 ways to initialize global mutexes, depending on
 *
 *  - \b static: the mutex is assigned the value AST_MUTEX_INIT_VALUE
 *        this is done at compile time, and is the way used on Linux.
 *        This method is not applicable to all platforms e.g. when the
 *        initialization needs that some code is run.
 *
 *  - \b on first use: the mutex is assigned a magic value at compile time,
 *        and ast_mutex_init() is called when this magic value is detected.
 *        This technique is generally applicable, though it has a bit of
 *        overhead on each access to check whether initialization is needed.
 *        On the other hand, the overall cost of a mutex_lock operation
 *        is such that this overhead is often negligible.

 *  - \b through constructors: for each mutex, a constructor function is
 *        defined, which then runs when the program (or the module)
 *        starts. The problem with this approach is that there is a
 *        lot of code duplication (a new block of code is created for
 *        each mutex). Also, it does not prevent a user from declaring
 *        a global mutex without going through the wrapper macros,
 *        so sane programming practices are still required.
 *
 * Eventually we should converge on a single method for all platforms.
 */

#ifndef _ASTERISK_LOCK_H
#define _ASTERISK_LOCK_H

#include <pthread.h>
#include <netdb.h>
#include <time.h>
#include <sys/param.h>

#include "asterisk/logger.h"

#define AST_PTHREADT_NULL (pthread_t) -1
#define AST_PTHREADT_STOP (pthread_t) -2

#ifdef __APPLE__
/* Provide the Linux initializers for MacOS X */
#define PTHREAD_MUTEX_RECURSIVE_NP			PTHREAD_MUTEX_RECURSIVE
#define PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP		{ 0x4d555458, \
							{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
							0x20 } }
#endif

#ifdef BSD
#ifdef __GNUC__
#define AST_MUTEX_INIT_W_CONSTRUCTORS
#else
#define AST_MUTEX_INIT_ON_FIRST_USE
#endif
#endif /* BSD */

/* From now on, Asterisk REQUIRES Recursive (not error checking) mutexes
   and will not run without them. */
#if defined(__CYGWIN__)
#define PTHREAD_MUTEX_RECURSIVE_NP	PTHREAD_MUTEX_RECURSIVE
#define PTHREAD_MUTEX_INIT_VALUE 	(ast_mutex_t)18
#define AST_MUTEX_KIND			PTHREAD_MUTEX_RECURSIVE_NP
#elif defined(PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP)
#define PTHREAD_MUTEX_INIT_VALUE	PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP
#define AST_MUTEX_KIND			PTHREAD_MUTEX_RECURSIVE_NP
#else
#define PTHREAD_MUTEX_INIT_VALUE	PTHREAD_MUTEX_INITIALIZER
#define AST_MUTEX_KIND			PTHREAD_MUTEX_RECURSIVE
#endif /* PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP */

#ifdef SOLARIS
#define AST_MUTEX_INIT_W_CONSTRUCTORS
#endif

#ifdef DEBUG_THREADS

#define __ast_mutex_logger(...) { if (canlog) ast_log(LOG_ERROR, __VA_ARGS__); else fprintf(stderr, __VA_ARGS__); }

#ifdef THREAD_CRASH
#define DO_THREAD_CRASH do { *((int *)(0)) = 1; } while(0)
#endif

#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>

#define AST_MUTEX_INIT_VALUE { PTHREAD_MUTEX_INIT_VALUE, { NULL }, { 0 }, 0, { NULL }, { 0 } }

#define AST_MAX_REENTRANCY 10

struct ast_mutex_info {
	pthread_mutex_t mutex;
	const char *file[AST_MAX_REENTRANCY];
	int lineno[AST_MAX_REENTRANCY];
	int reentrancy;
	const char *func[AST_MAX_REENTRANCY];
	pthread_t thread[AST_MAX_REENTRANCY];
};

typedef struct ast_mutex_info ast_mutex_t;

typedef pthread_cond_t ast_cond_t;

static inline int __ast_pthread_mutex_init_attr(const char *filename, int lineno, const char *func,
						const char *mutex_name, ast_mutex_t *t,
						pthread_mutexattr_t *attr) 
{
#ifdef AST_MUTEX_INIT_W_CONSTRUCTORS
	int canlog = strcmp(filename, "logger.c");

	if ((t->mutex) != ((pthread_mutex_t) PTHREAD_MUTEX_INITIALIZER)) {
		__ast_mutex_logger("%s line %d (%s): Error: mutex '%s' is already initialized.\n",
				   filename, lineno, func, mutex_name);
		__ast_mutex_logger("%s line %d (%s): Error: previously initialization of mutex '%s'.\n",
				   t->file, t->lineno, t->func, mutex_name);
#ifdef THREAD_CRASH
		DO_THREAD_CRASH;
#endif
		return 0;
	}
#endif

	t->file[0] = filename;
	t->lineno[0] = lineno;
	t->func[0] = func;
	t->thread[0]  = 0;
	t->reentrancy = 0;

	return pthread_mutex_init(&t->mutex, attr);
}

static inline int __ast_pthread_mutex_init(const char *filename, int lineno, const char *func,
					   const char *mutex_name, ast_mutex_t *t)
{
	static pthread_mutexattr_t  attr;

	pthread_mutexattr_init(&attr);
	pthread_mutexattr_settype(&attr, AST_MUTEX_KIND);

	return __ast_pthread_mutex_init_attr(filename, lineno, func, mutex_name, t, &attr);
}

static inline int __ast_pthread_mutex_destroy(const char *filename, int lineno, const char *func,
						const char *mutex_name, ast_mutex_t *t)
{
	int res;
	int canlog = strcmp(filename, "logger.c");

#ifdef AST_MUTEX_INIT_W_CONSTRUCTORS
	if ((t->mutex) == ((pthread_mutex_t) PTHREAD_MUTEX_INITIALIZER)) {
		__ast_mutex_logger("%s line %d (%s): Error: mutex '%s' is uninitialized.\n",
				   filename, lineno, func, mutex_name);
	}
#endif

	res = pthread_mutex_trylock(&t->mutex);
	switch (res) {
	case 0:
		pthread_mutex_unlock(&t->mutex);
		break;
	case EINVAL:
		__ast_mutex_logger("%s line %d (%s): Error: attempt to destroy invalid mutex '%s'.\n",
				  filename, lineno, func, mutex_name);
		break;
	case EBUSY:
		__ast_mutex_logger("%s line %d (%s): Error: attempt to destroy locked mutex '%s'.\n",
				   filename, lineno, func, mutex_name);
		__ast_mutex_logger("%s line %d (%s): Error: '%s' was locked here.\n",
				   t->file[t->reentrancy-1], t->lineno[t->reentrancy-1], t->func[t->reentrancy-1], mutex_name);
		break;
	}

	if ((res = pthread_mutex_destroy(&t->mutex)))
		__ast_mutex_logger("%s line %d (%s): Error destroying mutex: %s\n",
				   filename, lineno, func, strerror(res));
#ifndef PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP
	else
		t->mutex = PTHREAD_MUTEX_INIT_VALUE;
#endif
	t->file[0] = filename;
	t->lineno[0] = lineno;
	t->func[0] = func;

	return res;
}

#if defined(AST_MUTEX_INIT_W_CONSTRUCTORS)
/*! \brief  if AST_MUTEX_INIT_W_CONSTRUCTORS is defined, use file scope
 constrictors/destructors to create/destroy mutexes.  */
#define __AST_MUTEX_DEFINE(scope,mutex) \
	scope ast_mutex_t mutex = AST_MUTEX_INIT_VALUE; \
static void  __attribute__ ((constructor)) init_##mutex(void) \
{ \
	ast_mutex_init(&mutex); \
} \
static void  __attribute__ ((destructor)) fini_##mutex(void) \
{ \
	ast_mutex_destroy(&mutex); \
}
#elif defined(AST_MUTEX_INIT_ON_FIRST_USE)
/*! \note
 if AST_MUTEX_INIT_ON_FIRST_USE is defined, mutexes are created on
 first use.  The performance impact on FreeBSD should be small since
 the pthreads library does this itself to initialize errror checking
 (defaulty type) mutexes.  If nither is defined, the pthreads librariy
 does the initialization itself on first use. 
*/ 
#define __AST_MUTEX_DEFINE(scope,mutex) \
	scope ast_mutex_t mutex = AST_MUTEX_INIT_VALUE
#else /* AST_MUTEX_INIT_W_CONSTRUCTORS */
/* By default, use static initialization of mutexes.*/ 
#define __AST_MUTEX_DEFINE(scope,mutex) \
	scope ast_mutex_t mutex = AST_MUTEX_INIT_VALUE
#endif /* AST_MUTEX_INIT_W_CONSTRUCTORS */

static inline int __ast_pthread_mutex_lock(const char *filename, int lineno, const char *func,
                                           const char* mutex_name, ast_mutex_t *t)
{
	int res;
	int canlog = strcmp(filename, "logger.c");

#if defined(AST_MUTEX_INIT_W_CONSTRUCTORS) || defined(AST_MUTEX_INIT_ON_FIRST_USE)
	if ((t->mutex) == ((pthread_mutex_t) PTHREAD_MUTEX_INITIALIZER)) {
#ifdef AST_MUTEX_INIT_W_CONSTRUCTORS
		ast_mutex_logger("%s line %d (%s): Error: mutex '%s' is uninitialized.\n",
				 filename, lineno, func, mutex_name);
#endif
		ast_mutex_init(t);
	}
#endif /* defined(AST_MUTEX_INIT_W_CONSTRUCTORS) || defined(AST_MUTEX_INIT_ON_FIRST_USE) */

#ifdef DETECT_DEADLOCKS
	{
		time_t seconds = time(NULL);
		time_t current;
		do {
			res = pthread_mutex_trylock(&t->mutex);
			if (res == EBUSY) {
				current = time(NULL);
				if ((current - seconds) && (!((current - seconds) % 5))) {
					__ast_mutex_logger("%s line %d (%s): Deadlock? waited %d sec for mutex '%s'?\n",
							   filename, lineno, func, (int)(current - seconds), mutex_name);
					__ast_mutex_logger("%s line %d (%s): '%s' was locked here.\n",
							   t->file[t->reentrancy-1], t->lineno[t->reentrancy-1],
							   t->func[t->reentrancy-1], mutex_name);
				}
				usleep(200);
			}
		} while (res == EBUSY);
	}
#else
	res = pthread_mutex_lock(&t->mutex);
#endif /* DETECT_DEADLOCKS */

	if (!res) {
		if (t->reentrancy < AST_MAX_REENTRANCY) {
			t->file[t->reentrancy] = filename;
			t->lineno[t->reentrancy] = lineno;
			t->func[t->reentrancy] = func;
			t->thread[t->reentrancy] = pthread_self();
			t->reentrancy++;
		} else {
			__ast_mutex_logger("%s line %d (%s): '%s' really deep reentrancy!\n",
							   filename, lineno, func, mutex_name);
		}
	} else {
		__ast_mutex_logger("%s line %d (%s): Error obtaining mutex: %s\n",
				   filename, lineno, func, strerror(errno));
#ifdef THREAD_CRASH
		DO_THREAD_CRASH;
#endif
	}

	return res;
}

static inline int __ast_pthread_mutex_trylock(const char *filename, int lineno, const char *func,
                                              const char* mutex_name, ast_mutex_t *t)
{
	int res;
	int canlog = strcmp(filename, "logger.c");

#if defined(AST_MUTEX_INIT_W_CONSTRUCTORS) || defined(AST_MUTEX_INIT_ON_FIRST_USE)
	if ((t->mutex) == ((pthread_mutex_t) PTHREAD_MUTEX_INITIALIZER)) {
#ifdef AST_MUTEX_INIT_W_CONSTRUCTORS

		__ast_mutex_logger("%s line %d (%s): Error: mutex '%s' is uninitialized.\n",
				   filename, lineno, func, mutex_name);
#endif
		ast_mutex_init(t);
	}
#endif /* defined(AST_MUTEX_INIT_W_CONSTRUCTORS) || defined(AST_MUTEX_INIT_ON_FIRST_USE) */

	if (!(res = pthread_mutex_trylock(&t->mutex))) {
		if (t->reentrancy < AST_MAX_REENTRANCY) {
			t->file[t->reentrancy] = filename;
			t->lineno[t->reentrancy] = lineno;
			t->func[t->reentrancy] = func;
			t->thread[t->reentrancy] = pthread_self();
			t->reentrancy++;
		} else {
			__ast_mutex_logger("%s line %d (%s): '%s' really deep reentrancy!\n",
							   filename, lineno, func, mutex_name);
		}
	}

	return res;
}

static inline int __ast_pthread_mutex_unlock(const char *filename, int lineno, const char *func,
					     const char *mutex_name, ast_mutex_t *t)
{
	int res;
	int canlog = strcmp(filename, "logger.c");

#ifdef AST_MUTEX_INIT_W_CONSTRUCTORS
	if ((t->mutex) == ((pthread_mutex_t) PTHREAD_MUTEX_INITIALIZER)) {
		__ast_mutex_logger("%s line %d (%s): Error: mutex '%s' is uninitialized.\n",
				   filename, lineno, func, mutex_name);
	}
#endif

	if (t->reentrancy && (t->thread[t->reentrancy-1] != pthread_self())) {
		__ast_mutex_logger("%s line %d (%s): attempted unlock mutex '%s' without owning it!\n",
				   filename, lineno, func, mutex_name);
		__ast_mutex_logger("%s line %d (%s): '%s' was locked here.\n",
				   t->file[t->reentrancy-1], t->lineno[t->reentrancy-1], t->func[t->reentrancy-1], mutex_name);
#ifdef THREAD_CRASH
		DO_THREAD_CRASH;
#endif
	}

	if (--t->reentrancy < 0) {
		__ast_mutex_logger("%s line %d (%s): mutex '%s' freed more times than we've locked!\n",
				   filename, lineno, func, mutex_name);
		t->reentrancy = 0;
	}

	if (t->reentrancy < AST_MAX_REENTRANCY) {
		t->file[t->reentrancy] = NULL;
		t->lineno[t->reentrancy] = 0;
		t->func[t->reentrancy] = NULL;
		t->thread[t->reentrancy] = 0;
	}

	if ((res = pthread_mutex_unlock(&t->mutex))) {
		__ast_mutex_logger("%s line %d (%s): Error releasing mutex: %s\n", 
				   filename, lineno, func, strerror(res));
#ifdef THREAD_CRASH
		DO_THREAD_CRASH;
#endif
	}

	return res;
}

static inline int __ast_cond_init(const char *filename, int lineno, const char *func,
				  const char *cond_name, ast_cond_t *cond, pthread_condattr_t *cond_attr)
{
	return pthread_cond_init(cond, cond_attr);
}

static inline int __ast_cond_signal(const char *filename, int lineno, const char *func,
				    const char *cond_name, ast_cond_t *cond)
{
	return pthread_cond_signal(cond);
}

static inline int __ast_cond_broadcast(const char *filename, int lineno, const char *func,
				       const char *cond_name, ast_cond_t *cond)
{
	return pthread_cond_broadcast(cond);
}

static inline int __ast_cond_destroy(const char *filename, int lineno, const char *func,
				     const char *cond_name, ast_cond_t *cond)
{
	return pthread_cond_destroy(cond);
}

static inline int __ast_cond_wait(const char *filename, int lineno, const char *func,
				  const char *cond_name, const char *mutex_name,
				  ast_cond_t *cond, ast_mutex_t *t)
{
	int res;
	int canlog = strcmp(filename, "logger.c");

#ifdef AST_MUTEX_INIT_W_CONSTRUCTORS
	if ((t->mutex) == ((pthread_mutex_t) PTHREAD_MUTEX_INITIALIZER)) {
		__ast_mutex_logger("%s line %d (%s): Error: mutex '%s' is uninitialized.\n",
				   filename, lineno, func, mutex_name);
	}
#endif

	if (t->reentrancy && (t->thread[t->reentrancy-1] != pthread_self())) {
		__ast_mutex_logger("%s line %d (%s): attempted unlock mutex '%s' without owning it!\n",
				   filename, lineno, func, mutex_name);
		__ast_mutex_logger("%s line %d (%s): '%s' was locked here.\n",
				   t->file[t->reentrancy-1], t->lineno[t->reentrancy-1], t->func[t->reentrancy-1], mutex_name);
#ifdef THREAD_CRASH
		DO_THREAD_CRASH;
#endif
	}

	if (--t->reentrancy < 0) {
		__ast_mutex_logger("%s line %d (%s): mutex '%s' freed more times than we've locked!\n",
				   filename, lineno, func, mutex_name);
		t->reentrancy = 0;
	}

	if (t->reentrancy < AST_MAX_REENTRANCY) {
		t->file[t->reentrancy] = NULL;
		t->lineno[t->reentrancy] = 0;
		t->func[t->reentrancy] = NULL;
		t->thread[t->reentrancy] = 0;
	}

	if ((res = pthread_cond_wait(cond, &t->mutex))) {
		__ast_mutex_logger("%s line %d (%s): Error waiting on condition mutex '%s'\n", 
				   filename, lineno, func, strerror(res));
#ifdef THREAD_CRASH
		DO_THREAD_CRASH;
#endif
	} else {
		if (t->reentrancy < AST_MAX_REENTRANCY) {
			t->file[t->reentrancy] = filename;
			t->lineno[t->reentrancy] = lineno;
			t->func[t->reentrancy] = func;
			t->thread[t->reentrancy] = pthread_self();
			t->reentrancy++;
		} else {
			__ast_mutex_logger("%s line %d (%s): '%s' really deep reentrancy!\n",
							   filename, lineno, func, mutex_name);
		}
	}

	return res;
}

static inline int __ast_cond_timedwait(const char *filename, int lineno, const char *func,
				       const char *cond_name, const char *mutex_name, ast_cond_t *cond,
				       ast_mutex_t *t, const struct timespec *abstime)
{
	int res;
	int canlog = strcmp(filename, "logger.c");

#ifdef AST_MUTEX_INIT_W_CONSTRUCTORS
	if ((t->mutex) == ((pthread_mutex_t) PTHREAD_MUTEX_INITIALIZER)) {
		__ast_mutex_logger("%s line %d (%s): Error: mutex '%s' is uninitialized.\n",
				   filename, lineno, func, mutex_name);
	}
#endif

	if (t->reentrancy && (t->thread[t->reentrancy-1] != pthread_self())) {
		__ast_mutex_logger("%s line %d (%s): attempted unlock mutex '%s' without owning it!\n",
				   filename, lineno, func, mutex_name);
		__ast_mutex_logger("%s line %d (%s): '%s' was locked here.\n",
				   t->file[t->reentrancy-1], t->lineno[t->reentrancy-1], t->func[t->reentrancy-1], mutex_name);
#ifdef THREAD_CRASH
		DO_THREAD_CRASH;
#endif
	}

	if (--t->reentrancy < 0) {
		__ast_mutex_logger("%s line %d (%s): mutex '%s' freed more times than we've locked!\n",
				   filename, lineno, func, mutex_name);
		t->reentrancy = 0;
	}

	if (t->reentrancy < AST_MAX_REENTRANCY) {
		t->file[t->reentrancy] = NULL;
		t->lineno[t->reentrancy] = 0;
		t->func[t->reentrancy] = NULL;
		t->thread[t->reentrancy] = 0;
	}

	if ((res = pthread_cond_timedwait(cond, &t->mutex, abstime)) && (res != ETIMEDOUT)) {
		__ast_mutex_logger("%s line %d (%s): Error waiting on condition mutex '%s'\n", 
				   filename, lineno, func, strerror(res));
#ifdef THREAD_CRASH
		DO_THREAD_CRASH;
#endif
	} else {
		if (t->reentrancy < AST_MAX_REENTRANCY) {
			t->file[t->reentrancy] = filename;
			t->lineno[t->reentrancy] = lineno;
			t->func[t->reentrancy] = func;
			t->thread[t->reentrancy] = pthread_self();
			t->reentrancy++;
		} else {
			__ast_mutex_logger("%s line %d (%s): '%s' really deep reentrancy!\n",
							   filename, lineno, func, mutex_name);
		}
	}

	return res;
}

#define ast_mutex_init(pmutex) __ast_pthread_mutex_init(__FILE__, __LINE__, __PRETTY_FUNCTION__, #pmutex, pmutex)
#define ast_mutex_destroy(a) __ast_pthread_mutex_destroy(__FILE__, __LINE__, __PRETTY_FUNCTION__, #a, a)
#define ast_mutex_lock(a) __ast_pthread_mutex_lock(__FILE__, __LINE__, __PRETTY_FUNCTION__, #a, a)
#define ast_mutex_unlock(a) __ast_pthread_mutex_unlock(__FILE__, __LINE__, __PRETTY_FUNCTION__, #a, a)
#define ast_mutex_trylock(a) __ast_pthread_mutex_trylock(__FILE__, __LINE__, __PRETTY_FUNCTION__, #a, a)
#define ast_cond_init(cond, attr) __ast_cond_init(__FILE__, __LINE__, __PRETTY_FUNCTION__, #cond, cond, attr)
#define ast_cond_destroy(cond) __ast_cond_destroy(__FILE__, __LINE__, __PRETTY_FUNCTION__, #cond, cond)
#define ast_cond_signal(cond) __ast_cond_signal(__FILE__, __LINE__, __PRETTY_FUNCTION__, #cond, cond)
#define ast_cond_broadcast(cond) __ast_cond_broadcast(__FILE__, __LINE__, __PRETTY_FUNCTION__, #cond, cond)
#define ast_cond_wait(cond, mutex) __ast_cond_wait(__FILE__, __LINE__, __PRETTY_FUNCTION__, #cond, #mutex, cond, mutex)
#define ast_cond_timedwait(cond, mutex, time) __ast_cond_timedwait(__FILE__, __LINE__, __PRETTY_FUNCTION__, #cond, #mutex, cond, mutex, time)

#else /* !DEBUG_THREADS */


#define AST_MUTEX_INIT_VALUE	PTHREAD_MUTEX_INIT_VALUE


typedef pthread_mutex_t ast_mutex_t;

static inline int ast_mutex_init(ast_mutex_t *pmutex)
{
	pthread_mutexattr_t attr;
	pthread_mutexattr_init(&attr);
	pthread_mutexattr_settype(&attr, AST_MUTEX_KIND);
	return pthread_mutex_init(pmutex, &attr);
}

#define ast_pthread_mutex_init(pmutex,a) pthread_mutex_init(pmutex,a)

static inline int ast_mutex_unlock(ast_mutex_t *pmutex)
{
	return pthread_mutex_unlock(pmutex);
}

static inline int ast_mutex_destroy(ast_mutex_t *pmutex)
{
	return pthread_mutex_destroy(pmutex);
}

#if defined(AST_MUTEX_INIT_W_CONSTRUCTORS)
/* if AST_MUTEX_INIT_W_CONSTRUCTORS is defined, use file scope
 constrictors/destructors to create/destroy mutexes.  */ 
#define __AST_MUTEX_DEFINE(scope,mutex) \
	scope ast_mutex_t mutex = AST_MUTEX_INIT_VALUE; \
static void  __attribute__ ((constructor)) init_##mutex(void) \
{ \
	ast_mutex_init(&mutex); \
} \
static void  __attribute__ ((destructor)) fini_##mutex(void) \
{ \
	ast_mutex_destroy(&mutex); \
}

static inline int ast_mutex_lock(ast_mutex_t *pmutex)
{
	return pthread_mutex_lock(pmutex);
}

static inline int ast_mutex_trylock(ast_mutex_t *pmutex)
{
	return pthread_mutex_trylock(pmutex);
}

#elif defined(AST_MUTEX_INIT_ON_FIRST_USE)
/* if AST_MUTEX_INIT_ON_FIRST_USE is defined, mutexes are created on
 first use.  The performance impact on FreeBSD should be small since
 the pthreads library does this itself to initialize errror checking
 (defaulty type) mutexes.*/ 
#define __AST_MUTEX_DEFINE(scope,mutex) \
	scope ast_mutex_t mutex = AST_MUTEX_INIT_VALUE

static inline int ast_mutex_lock(ast_mutex_t *pmutex)
{
	if (*pmutex == (ast_mutex_t)AST_MUTEX_KIND)
		ast_mutex_init(pmutex);
	return pthread_mutex_lock(pmutex);
}
static inline int ast_mutex_trylock(ast_mutex_t *pmutex)
{
	if (*pmutex == (ast_mutex_t)AST_MUTEX_KIND)
		ast_mutex_init(pmutex);
	return pthread_mutex_trylock(pmutex);
}
#else
/* By default, use static initialization of mutexes.*/ 
#define __AST_MUTEX_DEFINE(scope,mutex) \
	scope ast_mutex_t mutex = AST_MUTEX_INIT_VALUE

static inline int ast_mutex_lock(ast_mutex_t *pmutex)
{
	return pthread_mutex_lock(pmutex);
}

static inline int ast_mutex_trylock(ast_mutex_t *pmutex)
{
	return pthread_mutex_trylock(pmutex);
}

#endif /* AST_MUTEX_INIT_W_CONSTRUCTORS */

typedef pthread_cond_t ast_cond_t;

static inline int ast_cond_init(ast_cond_t *cond, pthread_condattr_t *cond_attr)
{
	return pthread_cond_init(cond, cond_attr);
}

static inline int ast_cond_signal(ast_cond_t *cond)
{
	return pthread_cond_signal(cond);
}

static inline int ast_cond_broadcast(ast_cond_t *cond)
{
	return pthread_cond_broadcast(cond);
}

static inline int ast_cond_destroy(ast_cond_t *cond)
{
	return pthread_cond_destroy(cond);
}

static inline int ast_cond_wait(ast_cond_t *cond, ast_mutex_t *t)
{
	return pthread_cond_wait(cond, t);
}

static inline int ast_cond_timedwait(ast_cond_t *cond, ast_mutex_t *t, const struct timespec *abstime)
{
	return pthread_cond_timedwait(cond, t, abstime);
}

#endif /* !DEBUG_THREADS */

#define pthread_mutex_t use_ast_mutex_t_instead_of_pthread_mutex_t
#define pthread_mutex_lock use_ast_mutex_lock_instead_of_pthread_mutex_lock
#define pthread_mutex_unlock use_ast_mutex_unlock_instead_of_pthread_mutex_unlock
#define pthread_mutex_trylock use_ast_mutex_trylock_instead_of_pthread_mutex_trylock
#define pthread_mutex_init use_ast_mutex_init_instead_of_pthread_mutex_init
#define pthread_mutex_destroy use_ast_mutex_destroy_instead_of_pthread_mutex_destroy
#define pthread_cond_t use_ast_cond_t_instead_of_pthread_cond_t
#define pthread_cond_init use_ast_cond_init_instead_of_pthread_cond_init
#define pthread_cond_destroy use_ast_cond_destroy_instead_of_pthread_cond_destroy
#define pthread_cond_signal use_ast_cond_signal_instead_of_pthread_cond_signal
#define pthread_cond_broadcast use_ast_cond_broadcast_instead_of_pthread_cond_broadcast
#define pthread_cond_wait use_ast_cond_wait_instead_of_pthread_cond_wait
#define pthread_cond_timedwait use_ast_cond_timedwait_instead_of_pthread_cond_timedwait

#define AST_MUTEX_DEFINE_STATIC(mutex) __AST_MUTEX_DEFINE(static,mutex)

#define AST_MUTEX_INITIALIZER __use_AST_MUTEX_DEFINE_STATIC_rather_than_AST_MUTEX_INITIALIZER__

#define gethostbyname __gethostbyname__is__not__reentrant__use__ast_gethostbyname__instead__
#ifndef __linux__
#define pthread_create __use_ast_pthread_create_instead__
#endif

/*
 * Initial support for atomic instructions.
 * For platforms that have it, use the native cpu instruction to
 * implement them. For other platforms, resort to a 'slow' version
 * (defined in utils.c) that protects the atomic instruction with
 * a single lock.
 * The slow versions is always available, for testing purposes,
 * as ast_atomic_fetchadd_int_slow()
 */

int ast_atomic_fetchadd_int_slow(volatile int *p, int v);

#include "asterisk/inline_api.h"

/*! \brief Atomically add v to *pp and return * the previous value of *p.
 * This can be used to handle reference counts, and the return value
 * can be used to generate unique identifiers.
 */

#if defined ( __i386__)
AST_INLINE_API(int ast_atomic_fetchadd_int(volatile int *p, int v),
{
	__asm __volatile (
	"       lock   xaddl   %0, %1 ;        "
	: "+r" (v),                     /* 0 (result) */   
	  "=m" (*p)                     /* 1 */
	: "m" (*p));                    /* 2 */
	return (v);
})
#else   /* low performance version in utils.c */
AST_INLINE_API(int ast_atomic_fetchadd_int(volatile int *p, int v),
{
	return ast_atomic_fetchadd_int_slow(p, v);
})
#endif

/*! \brief decrement *p by 1 and return true if the variable has reached 0.
 * Useful e.g. to check if a refcount has reached 0.
 */
AST_INLINE_API(int ast_atomic_dec_and_test(volatile int *p),
{
	int a = ast_atomic_fetchadd_int(p, -1);
	return a == 1; /* true if the value is 0 now (so it was 1 previously) */
}
)

#endif /* _ASTERISK_LOCK_H */