plugin_loader.c

wifi 无线网络路由协议OLSR linux下C代码

/*
 * The olsr.org Optimized Link-State Routing daemon(olsrd)
 * Copyright (c) 2004, Andreas T鴑nesen([e-mail])
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions 
 * are met:
 *
 * * Redistributions of source code must retain the above copyright 
 *   notice, this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright 
 *   notice, this list of conditions and the following disclaimer in 
 *   the documentation and/or other materials provided with the 
 *   distribution.
 * * Neither the name of olsr.org, olsrd nor the names of its 
 *   contributors may be used to endorse or promote products derived 
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * Visit http://www.olsr.org for more information.
 *
 * If you find this software useful feel free to make a donation
 * to the project. For more information see the website or contact
 * the copyright holders.
 *
 * $Id: plugin_loader.c,v 1.32 2007/09/17 21:57:06 bernd67 Exp $
 */

#include "plugin_loader.h"
#include "olsrd_plugin.h"
#include "plugin_util.h"
#include "defs.h"
#include "olsr.h"

#include <dlfcn.h>

/* Local functions */
static int init_olsr_plugin(struct olsr_plugin *);
static int olsr_load_dl(char *, struct plugin_param *);
static int olsr_add_dl(struct olsr_plugin *);

static struct olsr_plugin *olsr_plugins = NULL;


/**
 *Function that loads all registered plugins
 *
 *@return the number of plugins loaded
 */
void olsr_load_plugins(void)
{
    struct plugin_entry *entry = olsr_cnf->plugins;
    int rv = 0;
    for (entry = olsr_cnf->plugins; entry != NULL; entry = entry->next) {
        if(olsr_load_dl(entry->name, entry->params) < 0) {
            rv = 1;
        }
    }
    if (rv != 0) {
        OLSR_PRINTF(0, "-- PLUGIN LOADING FAILED! --\n");
        exit(1);
    }
    OLSR_PRINTF(0, "-- ALL PLUGINS LOADED! --\n\n");
}

/**
 *Try to load a shared library and extract
 *the required information
 *
 *@param libname the name of the library(file)
 *
 *@return negative on error
 */
static int olsr_load_dl(char *libname, struct plugin_param *params)
{
    struct olsr_plugin *plugin = olsr_malloc(sizeof(struct olsr_plugin), "Plugin entry");
    int rv;

    OLSR_PRINTF(0, "---------- LOADING LIBRARY %s ----------\n", libname);

    plugin->dlhandle = dlopen(libname, RTLD_NOW);
    if(plugin->dlhandle == NULL) {
        const int save_errno = errno;
        OLSR_PRINTF(0, "DL loading failed: \"%s\"!\n", dlerror());
        free(plugin);
        errno = save_errno;
        return -1;
    }

    rv = olsr_add_dl(plugin);
    if (rv == -1) {
        const int save_errno = errno;
        dlclose(plugin->dlhandle);
        free(plugin);
        errno = save_errno;
    } else {
        plugin->params = params;

        /* Initialize the plugin */
        if (init_olsr_plugin(plugin) != 0) {
            rv = -1;
        }

        /* queue */
        plugin->next = olsr_plugins;
        olsr_plugins = plugin;
    }
    OLSR_PRINTF(0, "---------- LIBRARY %s %s ----------\n\n", libname, rv == 0 ? "LOADED" : "FAILED");
    return rv;
}

#if SUPPORT_OLD_PLUGIN_VERSIONS
static int try_old_versions(const struct olsr_plugin *plugin)
{
    get_interface_version_func get_interface_version;
    int *interface_version;

    OLSR_PRINTF(1, "trying v2 detection... ");
    get_interface_version = dlsym(plugin->dlhandle, "get_plugin_interface_version");
    if (get_interface_version != NULL) {
        return get_interface_version();
    }

    OLSR_PRINTF(1, "trying v1 detection... ");
    interface_version = dlsym(plugin->dlhandle, "plugin_interface_version");
    if (interface_version != NULL) {
        return *interface_version;
    }
    OLSR_PRINTF(0, "FAILED: \"%s\"\n", dlerror());
    return -1;
}
#else 
#define try_old_versions(plugin) -1
#endif

static int olsr_add_dl(struct olsr_plugin *plugin)
{
    get_interface_version_func get_interface_version;
    get_plugin_parameters_func get_plugin_parameters;
    int plugin_interface_version;

    /* Fetch the interface version function, 3 different ways */
    OLSR_PRINTF(0, "Checking plugin interface version: ");
    get_interface_version = dlsym(plugin->dlhandle, "olsrd_plugin_interface_version");
    if (get_interface_version == NULL) {
        plugin_interface_version = try_old_versions(plugin);
    } else {
        plugin_interface_version = get_interface_version();
    }
    if (plugin_interface_version == -1) {
        OLSR_PRINTF(0, "FAILED: \"%s\"\n", dlerror());
        return -1;
    }
    OLSR_PRINTF(0, " %d - OK\n", plugin_interface_version);
  
    if (plugin_interface_version < 5){
        /* old plugin interface */   
        OLSR_PRINTF(0, "\nWARNING: YOU ARE USING AN OLD DEPRECATED PLUGIN INTERFACE!\n"
                    "DETECTED VERSION %d AND THE CURRENT VERSION IS %d\n"
                    "PLEASE UPGRADE YOUR PLUGIN!\n", plugin_interface_version, MOST_RECENT_PLUGIN_INTERFACE_VERSION);
#if SUPPORT_OLD_PLUGIN_VERSIONS
        OLSR_PRINTF(0, "WILL CONTINUE IN 5 SECONDS...\n\n");      
        sleep(5);
#else
        return -1;
#endif
    }

#if SUPPORT_OLD_PLUGIN_VERSIONS
    /* new plugin interface */      
    if (plugin_interface_version < LAST_SUPPORTED_PLUGIN_INTERFACE_VERSION) {
        OLSR_PRINTF(0, "\n\nWARNING: VERSION MISMATCH!\n"
                    "DETECTED %d AND LAST SUPPORTED VERSION IS %d\n"
                    "THIS CAN CAUSE UNEXPECTED BEHAVIOUR AND CRASHES!\n"
                    "WILL CONTINUE IN 5 SECONDS...\n\n", get_interface_version(), LAST_SUPPORTED_PLUGIN_INTERFACE_VERSION);
        sleep(5);
    }
#endif
   
    /* Fetch the init function */
    OLSR_PRINTF(1, "Trying to fetch plugin init function: ");
    plugin->plugin_init = dlsym(plugin->dlhandle, "olsrd_plugin_init");
    if (plugin->plugin_init == NULL) {
        OLSR_PRINTF(0, "FAILED: \"%s\"\n", dlerror());
        return -1;
    }
    OLSR_PRINTF(1, "OK\n");

    OLSR_PRINTF(1, "Trying to fetch parameter table and it's size... \n");

    get_plugin_parameters = dlsym(plugin->dlhandle, "olsrd_get_plugin_parameters");
    if (get_plugin_parameters != NULL) {
        (*get_plugin_parameters)(&plugin->plugin_parameters, &plugin->plugin_parameters_size);
    } else {
#if SUPPORT_OLD_PLUGIN_VERSIONS
        /* Fetch the parameter function */
        OLSR_PRINTF(1, "Trying to fetch param function: ");

        plugin->register_param = dlsym(plugin->dlhandle, "olsrd_plugin_register_param");
        if(plugin->register_param == NULL) {
            OLSR_PRINTF(0, "FAILED: \"%s\"\n", dlerror());
            return -1;
        } else {
            OLSR_PRINTF(1, "OK\n");
        }

        plugin->plugin_parameters      = NULL;
        plugin->plugin_parameters_size = 0;
#else
        OLSR_PRINTF(0, "Old plugin interfaces are not supported\n");
        return -1;
#endif
    }
    return 0;
}


/**
 *Initialize a loaded plugin
 *This includes sending information
 *from olsrd to the plugin and
 *register the functions from the plugin with olsrd
 *
 *@param entry the plugin to initialize
 *
 *@return -1 if there was an error
 */
static int init_olsr_plugin(struct olsr_plugin *entry)
{
    int rv = 0;
    struct plugin_param *params;
    OLSR_PRINTF(1, "Sending parameters...\n");
    for(params = entry->params; params != NULL; params = params->next) {
        OLSR_PRINTF(1, "\"%s\"/\"%s\"... ", params->key, params->value);
        if (entry->plugin_parameters_size != 0) {
            unsigned int i;
            int rc = 0;
            for (i = 0; i < entry->plugin_parameters_size; i++) {
                if (0 == entry->plugin_parameters[i].name[0] ||
                    0 == strcasecmp(entry->plugin_parameters[i].name, params->key))
                {
                    /* we have found it! */
                    rc = entry->plugin_parameters[i].set_plugin_parameter(params->value, entry->plugin_parameters[i].data,
                        0 == entry->plugin_parameters[i].name[0] ? (set_plugin_parameter_addon)params->key : entry->plugin_parameters[i].addon);
                    if (rc != 0) {
                        fprintf(stderr, "\nFatal error in plugin parameter \"%s\"/\"%s\"\n", params->key, params->value);
                        rv = -1;
                    }
                    break;
                }
            }
            if (i >= entry->plugin_parameters_size) {
                OLSR_PRINTF(0, "Ignored parameter \"%s\"\n", params->key);
            } else {
                OLSR_PRINTF(1, "%s: %s\n", params->key, rc == 0 ? "OK" : "FAILED");
                if (rc != 0) {
                    rv = -1;
                }
            }
#if SUPPORT_OLD_PLUGIN_VERSIONS
        } else if(entry->register_param != NULL) {
            int rc;
            OLSR_PRINTF(0, "Registering parameter \"%s\": ", params->key);
            rc = entry->register_param(params->key, params->value);
            if(rc < 0) {
                fprintf(stderr, "\nFatal error in plugin parameter \"%s\"/\"%s\"\n", params->key, params->value);
                exit(EXIT_FAILURE);
            }
            OLSR_PRINTF(0, "%s\n", rc == 0 ? "FAILED" : "OK");
#endif
        } else {
            OLSR_PRINTF(0, "I don't know what to do with \"%s\"!\n", params->key);
            rv = -1;
        }
    }

    OLSR_PRINTF(1, "Running plugin_init function...\n");
    entry->plugin_init();
    return rv;
}


/**
 *Close all loaded plugins
 */
void olsr_close_plugins(void)
{
    struct olsr_plugin *entry;

    OLSR_PRINTF(0, "Closing plugins...\n");
    for(entry = olsr_plugins; entry != NULL; entry = entry->next) {
        dlclose(entry->dlhandle);
        entry->dlhandle = NULL;
    }
}

/*
 * Local Variables:
 * mode: c
 * style: linux
 * c-basic-offset: 4
 * indent-tabs-mode: nil
 * End:
 */