loader.c

在asterisk平台写注册命令的程序

/*
 * 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 Module Loader
 * 
 */

#include <stdio.h>
#include <dirent.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision: 8162 $")

#include "asterisk/module.h"
#include "asterisk/options.h"
#include "asterisk/config.h"
#include "asterisk/logger.h"
#include "asterisk/channel.h"
#include "asterisk/term.h"
#include "asterisk/manager.h"
#include "asterisk/cdr.h"
#include "asterisk/enum.h"
#include "asterisk/rtp.h"
#include "asterisk/lock.h"
#ifdef DLFCNCOMPAT
#include "asterisk/dlfcn-compat.h"
#else
#include <dlfcn.h>
#endif
#include "asterisk/md5.h"

#ifndef RTLD_NOW
#define RTLD_NOW 0
#endif

AST_MUTEX_DEFINE_STATIC(modlock);
AST_MUTEX_DEFINE_STATIC(reloadlock);

static struct module *module_list=NULL;
static int modlistver = 0;

static unsigned char expected_key[] =
{ 0x8e, 0x93, 0x22, 0x83, 0xf5, 0xc3, 0xc0, 0x75,
  0xff, 0x8b, 0xa9, 0xbe, 0x7c, 0x43, 0x74, 0x63 };

struct module {
	int (*load_module)(void);
	int (*unload_module)(void);
	int (*usecount)(void);
	char *(*description)(void);
	char *(*key)(void);
	int (*reload)(void);
	void *lib;
	char resource[256];
	struct module *next;
};

static struct loadupdate {
	int (*updater)(void);
	struct loadupdate *next;
} *updaters = NULL;

static int printdigest(unsigned char *d)
{
	int x;
	char buf[256];
	char buf2[16];
	snprintf(buf, sizeof(buf), "Unexpected signature:");
	for (x=0; x<16; x++) {
		snprintf(buf2, sizeof(buf2), " %02x", *(d++));
		strcat(buf, buf2);
	}
	strcat(buf, "\n");
	ast_log(LOG_DEBUG, "%s", buf);
	return 0;
}

static int key_matches(unsigned char *key1, unsigned char *key2)
{
	int match = 1;
	int x;
	for (x=0; x<16; x++) {
		match &= (key1[x] == key2[x]);
	}
	return match;
}

static int verify_key(unsigned char *key)
{
	struct MD5Context c;
	unsigned char digest[16];
	MD5Init(&c);
	MD5Update(&c, key, strlen((char *)key));
	MD5Final(digest, &c);
	if (key_matches(expected_key, digest))
		return 0;
	printdigest(digest);
	return -1;
}

int ast_unload_resource(const char *resource_name, int force)
{
	struct module *m, *ml = NULL;
	int res = -1;
	if (ast_mutex_lock(&modlock))
		ast_log(LOG_WARNING, "Failed to lock\n");
	m = module_list;
	while(m) {
		if (!strcasecmp(m->resource, resource_name)) {
			if ((res = m->usecount()) > 0)  {
				if (force) 
					ast_log(LOG_WARNING, "Warning:  Forcing removal of module %s with use count %d\n", resource_name, res);
				else {
					ast_log(LOG_WARNING, "Soft unload failed, '%s' has use count %d\n", resource_name, res);
					ast_mutex_unlock(&modlock);
					return -1;
				}
			}
			res = m->unload_module();
			if (res) {
				ast_log(LOG_WARNING, "Firm unload failed for %s\n", resource_name);
				if (force <= AST_FORCE_FIRM) {
					ast_mutex_unlock(&modlock);
					return -1;
				} else
					ast_log(LOG_WARNING, "** Dangerous **: Unloading resource anyway, at user request\n");
			}
			if (ml)
				ml->next = m->next;
			else
				module_list = m->next;
			dlclose(m->lib);
			free(m);
			break;
		}
		ml = m;
		m = m->next;
	}
	modlistver = rand();
	ast_mutex_unlock(&modlock);
	ast_update_use_count();
	return res;
}

char *ast_module_helper(char *line, char *word, int pos, int state, int rpos, int needsreload)
{
	struct module *m;
	int which=0;
	char *ret;

	if (pos != rpos)
		return NULL;
	ast_mutex_lock(&modlock);
	m = module_list;
	while(m) {
		if (!strncasecmp(word, m->resource, strlen(word)) && (m->reload || !needsreload)) {
			if (++which > state)
				break;
		}
		m = m->next;
	}
	if (m) {
		ret = strdup(m->resource);
	} else {
		ret = NULL;
		if (!strncasecmp(word, "extconfig", strlen(word))) {
			if (++which > state)
				ret = strdup("extconfig");
		} else if (!strncasecmp(word, "manager", strlen(word))) {
			if (++which > state)
				ret = strdup("manager");
		} else if (!strncasecmp(word, "enum", strlen(word))) {
			if (++which > state)
				ret = strdup("enum");
		} else if (!strncasecmp(word, "rtp", strlen(word))) {
			if (++which > state)
				ret = strdup("rtp");
		}
			
	}
	ast_mutex_unlock(&modlock);
	return ret;
}

int ast_module_reload(const char *name)
{
	struct module *m;
	int reloaded = 0;
	int oldversion;
	int (*reload)(void);
	/* We'll do the logger and manager the favor of calling its reload here first */

	if (ast_mutex_trylock(&reloadlock)) {
		ast_verbose("The previous reload command didn't finish yet\n");
		return -1;
	}
	if (!name || !strcasecmp(name, "extconfig")) {
		read_config_maps();
		reloaded = 2;
	}
	if (!name || !strcasecmp(name, "manager")) {
		reload_manager();
		reloaded = 2;
	}
	if (!name || !strcasecmp(name, "cdr")) {
		ast_cdr_engine_reload();
		reloaded = 2;
	}
	if (!name || !strcasecmp(name, "enum")) {
		ast_enum_reload();
		reloaded = 2;
	}
	if (!name || !strcasecmp(name, "rtp")) {
		ast_rtp_reload();
		reloaded = 2;
	}
	if (!name || !strcasecmp(name, "dnsmgr")) {
		dnsmgr_reload();
		reloaded = 2;
	}
	//*****************************************************
	//****  add by wangqiang*****************
	if(!name||!strcasecmp(name,"dbfile")){
		dbfile_reload();
		reload=2;
	}
	time(&ast_lastreloadtime);

	ast_mutex_lock(&modlock);
	oldversion = modlistver;
	m = module_list;
	while(m) {
		if (!name || !strcasecmp(name, m->resource)) {
			if (reloaded < 1)
				reloaded = 1;
			reload = m->reload;
			ast_mutex_unlock(&modlock);
			if (reload) {
				reloaded = 2;
				if (option_verbose > 2) 
					ast_verbose(VERBOSE_PREFIX_3 "Reloading module '%s' (%s)\n", m->resource, m->description());
				reload();
			}
			ast_mutex_lock(&modlock);
			if (oldversion != modlistver)
				break;
		}
		m = m->next;
	}
	ast_mutex_unlock(&modlock);
	ast_mutex_unlock(&reloadlock);
	return reloaded;
}

static int __load_resource(const char *resource_name, const struct ast_config *cfg)
{
	static char fn[256];
	int errors=0;
	int res;
	struct module *m;
	int flags=RTLD_NOW;
#ifdef RTLD_GLOBAL
	char *val;
#endif
	unsigned char *key;
	char tmp[80];

	if (strncasecmp(resource_name, "res_", 4)) {
#ifdef RTLD_GLOBAL
		if (cfg) {
			if ((val = ast_variable_retrieve(cfg, "global", resource_name))
					&& ast_true(val))
				flags |= RTLD_GLOBAL;
		}
#endif
	} else {
		/* Resource modules are always loaded global and lazy */
#ifdef RTLD_GLOBAL
		flags = (RTLD_GLOBAL | RTLD_LAZY);
#else
		flags = RTLD_LAZY;
#endif
	}
	
	if (ast_mutex_lock(&modlock))
		ast_log(LOG_WARNING, "Failed to lock\n");
	m = module_list;
	while(m) {
		if (!strcasecmp(m->resource, resource_name)) {
			ast_log(LOG_WARNING, "Module '%s' already exists\n", resource_name);
			ast_mutex_unlock(&modlock);
			return -1;
		}
		m = m->next;
	}
	m = malloc(sizeof(struct module));	
	if (!m) {
		ast_log(LOG_WARNING, "Out of memory\n");
		ast_mutex_unlock(&modlock);
		return -1;
	}
	strncpy(m->resource, resource_name, sizeof(m->resource)-1);
	if (resource_name[0] == '/') {
		strncpy(fn, resource_name, sizeof(fn)-1);
	} else {
		snprintf(fn, sizeof(fn), "%s/%s", (char *)ast_config_AST_MODULE_DIR, resource_name);