gear-lib/libplugin/libplugin.c

/******************************************************************************
 * Copyright (C) 2014-2020 Zhifeng Gong <gozfree@163.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 ******************************************************************************/
#include "libplugin.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <dlfcn.h>
#include <libmacro.h>

struct plugin_manager *plugin_manager_create()
{
    struct plugin_manager *pm = CALLOC(1, struct plugin_manager);
    if (!pm) {
        printf("malloc failed!\n");
        return NULL;
    }
    INIT_LIST_HEAD(&pm->plugins);
    return pm;
}

void plugin_manager_destroy(struct plugin_manager *pm)
{
    if (!pm) {
        return;
    }
}

static void *plugin_get_func(struct plugin *p, const char *name)
{
    if (!p || !name) {
        return NULL;
    }
    struct plugin *q = dlsym(p->handle, name);
    if (!q) {
        printf("dlsym failed:%s\n", dlerror());
        return NULL;
    }
    return q;
}


struct plugin *plugin_lookup(struct plugin_manager *pm, const char *name)
{
    if (!pm || !name)
        return NULL;

    struct list_head* head = NULL;
    struct plugin* p = NULL;

    list_for_each(head, &pm->plugins) {
        p = list_entry(head, struct plugin, entry);
        if (0 == strcmp(p->name, name)) {
            return plugin_get_func(p, name);
        }
    }

    return NULL;
}

struct plugin *plugin_load(struct plugin_manager *pm, const char *path, const char *name)
{
    struct plugin *sym = NULL;
    struct plugin *p = NULL;
    void *handle = dlopen(path, RTLD_LAZY);
    if (!handle) {
        printf("dlopen failed: %s\n", dlerror());
        goto failed;
    }
    p = plugin_lookup(pm, name);
    if (p) {
        printf("plugin %s has already loaded!\n", name);
        return p;
    }
    sym = dlsym(handle, name);
    if (!sym) {
        printf("incompatible plugin, dlsym failed: %s\n", dlerror());
        goto failed;
    }
    p = CALLOC(1, struct plugin);
    if (!p) {
        goto failed;
    }
    p->handle = handle;
    p->name = strdup(name);
    p->path = strdup(path);
    list_add(&p->entry, &pm->plugins);
    return p;

failed:
    if (handle) dlclose(handle);
    if (p) {
        free(p->name);
        free(p->path);
        free(p);
    }
    return NULL;
}

void plugin_unload(struct plugin_manager *pm, const char *name)
{
    struct plugin *p, *tmp;
    list_for_each_entry_safe(p, tmp, &pm->plugins, entry) {
        dlclose(p->handle);
        list_del(&p->entry);
        free(p->name);
        free(p->path);
        free(p);
    }
}

struct plugin *plugin_reload(struct plugin_manager *pm, const char *path, const char *name)
{
    plugin_unload(pm, name);
    return plugin_load(pm, path, name);
}