lock.h

Asterisk-1.4.4最新内核源代码

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2006, Digium, Inc.
 *
 * Mark Spencer <[e-mail]>
 *
 * 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 different implementation of the functions,
 * depending on the platform, the use of DEBUG_THREADS, and the way
 * module-level mutexes are initialized.
 *
 *  - \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 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.
 */

#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"

/* internal macro to profile mutexes. Only computes the delay on
 * non-blocking calls.
 */
#ifndef	HAVE_MTX_PROFILE
#define	__MTX_PROF(a)	return pthread_mutex_lock((a))
#else
#define	__MTX_PROF(a)	do {			\
	int i;					\
	/* profile only non-blocking events */	\
	ast_mark(mtx_prof, 1);			\
	i = pthread_mutex_trylock((a));		\
	ast_mark(mtx_prof, 0);			\
	if (!i)					\
		return i;			\
	else					\
		return pthread_mutex_lock((a)); \
	} while (0)
#endif	/* HAVE_MTX_PROFILE */

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

#if defined(SOLARIS) || defined(BSD)
#define AST_MUTEX_INIT_W_CONSTRUCTORS
#endif /* SOLARIS || BSD */

/* Asterisk REQUIRES recursive (not error checking) mutexes
   and will not run without them. */
#if 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 DEBUG_THREADS

#define __ast_mutex_logger(...)  do { if (canlog) ast_log(LOG_ERROR, __VA_ARGS__); else fprintf(stderr, __VA_ARGS__); } while (0)

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

static void __attribute__((constructor)) init_empty_mutex(void)
{
	memset(&empty_mutex, 0, sizeof(empty_mutex));
}

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)) {
		if ((t->mutex) != (empty_mutex)) {
			__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[0], t->lineno[0], t->func[0], mutex_name);
			DO_THREAD_CRASH;
			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);
}
#define ast_mutex_init(pmutex) __ast_pthread_mutex_init(__FILE__, __LINE__, __PRETTY_FUNCTION__, #pmutex, pmutex)

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;
}

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)
	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);
		ast_mutex_init(t);
	}
#endif /* AST_MUTEX_INIT_W_CONSTRUCTORS */

#ifdef DETECT_DEADLOCKS
	{
		time_t seconds = time(NULL);
		time_t current;
		do {
#ifdef	HAVE_MTX_PROFILE
			ast_mark(mtx_prof, 1);
#endif
			res = pthread_mutex_trylock(&t->mutex);
#ifdef	HAVE_MTX_PROFILE
			ast_mark(mtx_prof, 0);
#endif
			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
#ifdef	HAVE_MTX_PROFILE
	ast_mark(mtx_prof, 1);
	res = pthread_mutex_trylock(&t->mutex);
	ast_mark(mtx_prof, 0);
	if (res)
#endif
	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));
		DO_THREAD_CRASH;
	}

	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)
	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);
		ast_mutex_init(t);
	}
#endif /* AST_MUTEX_INIT_W_CONSTRUCTORS */

	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);
		DO_THREAD_CRASH;
	}

	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));
		DO_THREAD_CRASH;
	}

	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);