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/*
** Zabbix
** Copyright (C) 2001-2014 Zabbix SIA
**
** 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
**/
#include "common.h"
#include "module.h"
#include "zbxmodules.h"
#include "log.h"
#include "sysinfo.h"
#define ZBX_MODULE_FUNC_INIT "zbx_module_init"
#define ZBX_MODULE_FUNC_API_VERSION "zbx_module_api_version"
#define ZBX_MODULE_FUNC_ITEM_LIST "zbx_module_item_list"
#define ZBX_MODULE_FUNC_ITEM_PROCESS "zbx_module_item_process"
#define ZBX_MODULE_FUNC_ITEM_TIMEOUT "zbx_module_item_timeout"
#define ZBX_MODULE_FUNC_UNINIT "zbx_module_uninit"
static void **modules = NULL;
/******************************************************************************
* *
* Function: register_module *
* *
* Purpose: Add module to the list of loaded modules (dynamic libraries). *
* It skips a module if it is already registered. *
* *
* Parameters: module - library handler *
* *
* Return value: SUCCEED - if module is successfully registered *
* FAIL - if module is already registered *
* *
******************************************************************************/
static int register_module(void *module)
{
const char *__function_name = "register_module";
int i = 0, ret = FAIL;
zabbix_log(LOG_LEVEL_DEBUG, "In %s()", __function_name);
if (NULL == modules)
{
modules = zbx_malloc(modules, sizeof(void *));
modules[0] = NULL;
}
while (NULL != modules[i])
{
if (module == modules[i]) /* a module is already registered */
goto out;
i++;
}
modules = zbx_realloc(modules, (i + 2) * sizeof(void *));
modules[i] = module;
modules[i + 1] = NULL;
ret = SUCCEED;
out:
zabbix_log(LOG_LEVEL_DEBUG, "End of %s():%s", __function_name, zbx_result_string(ret));
return ret;
}
/******************************************************************************
* *
* Function: load_modules *
* *
* Purpose: load loadable modules (dynamic libraries) *
* It skips a module in case of any errors *
* *
* Parameters: path - directory where modules are located *
* file_names - list of module names *
* timeout - timeout in seconds for processing of items by module *
* verbose - output list of loaded modules *
* *
* Return value: SUCCEED - all modules is successfully loaded *
* FAIL - loading of modules failed *
* *
******************************************************************************/
int load_modules(const char *path, char **file_names, int timeout, int verbose)
{
const char *__function_name = "load_modules";
char **file_name, *buffer = NULL;
void *lib;
char full_name[MAX_STRING_LEN], error[MAX_STRING_LEN];
int (*func_init)(), (*func_version)();
ZBX_METRIC *(*func_list)();
void (*func_timeout)();
int i, ret = FAIL;
zabbix_log(LOG_LEVEL_DEBUG, "In %s()", __function_name);
for (file_name = file_names; NULL != *file_name; file_name++)
{
zbx_snprintf(full_name, sizeof(full_name), "%s/%s", path, *file_name);
zabbix_log(LOG_LEVEL_DEBUG, "loading module \"%s\"", full_name);
if (NULL == (lib = dlopen(full_name, RTLD_NOW)))
{
zabbix_log(LOG_LEVEL_CRIT, "cannot load module \"%s\": %s", *file_name, dlerror());
goto fail;
}
*(void **)(&func_version) = dlsym(lib, ZBX_MODULE_FUNC_API_VERSION);
if (NULL == func_version)
{
zabbix_log(LOG_LEVEL_CRIT, "cannot find \"" ZBX_MODULE_FUNC_API_VERSION "()\""
" function in module \"%s\": %s", *file_name, dlerror());
dlclose(lib);
goto fail;
}
if (ZBX_MODULE_API_VERSION_ONE != (i = func_version()))
{
zabbix_log(LOG_LEVEL_CRIT, "unsupported module \"%s\" version: %d", *file_name, i);
dlclose(lib);
goto fail;
}
*(void **)(&func_init) = dlsym(lib, ZBX_MODULE_FUNC_INIT);
if (NULL == func_init)
{
zabbix_log(LOG_LEVEL_CRIT, "cannot find \"" ZBX_MODULE_FUNC_INIT "()\""
" function in module \"%s\": %s", *file_name, dlerror());
dlclose(lib);
goto fail;
}
if (ZBX_MODULE_OK != func_init())
{
zabbix_log(LOG_LEVEL_CRIT, "cannot initialize module \"%s\"", *file_name);
dlclose(lib);
goto fail;
}
/* the function is optional, zabbix will load the module even if it is missing */
*(void **)(&func_timeout) = dlsym(lib, ZBX_MODULE_FUNC_ITEM_TIMEOUT);
if (NULL == func_timeout)
{
zabbix_log(LOG_LEVEL_DEBUG, "cannot find \"" ZBX_MODULE_FUNC_ITEM_TIMEOUT "()\""
" function in module \"%s\": %s", *file_name, dlerror());
}
else
func_timeout(timeout);
*(void **)(&func_list) = dlsym(lib, ZBX_MODULE_FUNC_ITEM_LIST);
if (NULL == func_list)
{
zabbix_log(LOG_LEVEL_WARNING, "cannot find \"" ZBX_MODULE_FUNC_ITEM_LIST "()\""
" function in module \"%s\": %s", *file_name, dlerror());
dlclose(lib);
continue;
}
if (SUCCEED == register_module(lib))
{
ZBX_METRIC *metrics;
metrics = func_list();
for (i = 0; NULL != metrics[i].key; i++)
{
/* accept only CF_HAVEPARAMS flag from module items */
metrics[i].flags &= CF_HAVEPARAMS;
/* the flag means that the items comes from a loadable module */
metrics[i].flags |= CF_MODULE;
if (SUCCEED != add_metric(&metrics[i], error, sizeof(error)))
{
zabbix_log(LOG_LEVEL_CRIT, "cannot load module \"%s\": %s", *file_name, error);
exit(EXIT_FAILURE);
}
}
if (1 == verbose)
{
if (NULL != buffer)
buffer = zbx_strdcat(buffer, ", ");
buffer = zbx_strdcat(buffer, *file_name);
}
}
}
if (NULL != buffer)
zabbix_log(LOG_LEVEL_WARNING, "loaded modules: %s", buffer);
ret = SUCCEED;
fail:
zbx_free(buffer);
zabbix_log(LOG_LEVEL_DEBUG, "End of %s():%s", __function_name, zbx_result_string(ret));
return ret;
}
/******************************************************************************
* *
* Function: unload_modules *
* *
* Purpose: Unload already loaded loadable modules (dynamic libraries). *
* It is called on process shutdown. *
* *
******************************************************************************/
void unload_modules()
{
const char *__function_name = "unload_modules";
int (*func_uninit)();
void **module;
zabbix_log(LOG_LEVEL_DEBUG, "In %s()", __function_name);
/* there is no registered modules */
if (NULL == modules)
return;
for (module = modules; NULL != *module; module++)
{
*(void **)(&func_uninit) = dlsym(*module, ZBX_MODULE_FUNC_UNINIT);
if (NULL == func_uninit)
{
zabbix_log(LOG_LEVEL_DEBUG, "cannot find \"" ZBX_MODULE_FUNC_UNINIT "()\" function: %s",
dlerror());
dlclose(*module);
continue;
}
if (ZBX_MODULE_OK != func_uninit())
zabbix_log(LOG_LEVEL_WARNING, "uninitialization failed");
dlclose(*module);
}
zbx_free(modules);
zabbix_log(LOG_LEVEL_DEBUG, "End of %s()", __function_name);
}
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