lock.h

一个非常美妙的proxy。功能强大。基于sip的协议。如果还要的话

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, 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.
 */

#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)
/* 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)
/* 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;
	}