/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

/*  Fluent Bit

 *  ==========

 *  Copyright (C) 2015-2024 The Fluent Bit Authors

 *

 *  Licensed under the Apache License, Version 2.0 (the "License");

 *  you may not use this file except in compliance with the License.

 *  You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 *  Unless required by applicable law or agreed to in writing, software

 *  distributed under the License is distributed on an "AS IS" BASIS,

 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 *  See the License for the specific language governing permissions and

 *  limitations under the License.

 */

#include <fluent-bit/flb_compat.h>

#include <fluent-bit/flb_info.h>

#include <fluent-bit/flb_mem.h>

#include <fluent-bit/flb_log.h>

#include <fluent-bit/flb_error.h>

#include <fluent-bit/flb_kv.h>

#include <fluent-bit/flb_config_format.h>

#include <fluent-bit/flb_utils.h>

#include <fluent-bit/flb_plugin.h>

#include <fluent-bit/flb_plugin_proxy.h>

#include <cfl/cfl_sds.h>

#include <cfl/cfl_variant.h>

#include <cfl/cfl_kvlist.h>

#include <sys/types.h>

#include <sys/stat.h>

#define PLUGIN_PREFIX           "flb-"

#define PLUGIN_EXTENSION        ".so"

#define PLUGIN_STRUCT_SUFFIX    "_plugin"

#define PLUGIN_STR_MIN                                              \

    ((sizeof(PLUGIN_PREFIX) - 1) + sizeof(PLUGIN_EXTENSION) - 1)

static int is_input(char *name)

{

    if (strncmp(name, "in_", 3) == 0) {

        return FLB_TRUE;

    }

    return FLB_FALSE;

}

static int is_filter(char *name)

{

    if (strncmp(name, "filter_", 7) == 0) {

        return FLB_TRUE;

    }

    return FLB_FALSE;

}

static int is_processor(char *name)

{

    if (strncmp(name, "processor_", 10) == 0) {

        return FLB_TRUE;

    }

    return FLB_FALSE;

}

static int is_output(char *name)

{

    if (strncmp(name, "out_", 4) == 0) {

        return FLB_TRUE;

    }

    return FLB_FALSE;

}

static void *get_handle(const char *path)

{

    void *handle;

    handle = dlopen(path, RTLD_LAZY);

    if (!handle) {

        flb_error("[plugin] dlopen() %s", dlerror());

        return NULL;

    }

    return handle;

}

static void *load_symbol(void *dso_handle, const char *symbol)

{

    void *s;

    dlerror();

    s = dlsym(dso_handle, symbol);

    if (dlerror() != NULL) {

        return NULL;

    }

    return s;

}

/*

 * From a given path file (.so file), retrieve the expected structure name

 * used to perform the plugin registration.

 */

static char *path_to_plugin_name(char *path)

{

    int len;

    int o_len;

    char *bname;

    char *name;

    char *p;

    /* Get the basename of the file */

    bname = basename(path);

    if (!bname) {

        flb_error("[plugin] could not resolve basename(3) of the plugin");

        return NULL;

    }

    len = strlen(bname);

    if (len < PLUGIN_STR_MIN) {

        flb_error("[plugin] invalid plugin name: %s", bname);

        return NULL;

    }

    if (strncmp(bname, PLUGIN_PREFIX, sizeof(PLUGIN_PREFIX) - 1) != 0) {

        flb_error("[plugin] invalid plugin prefix: %s", bname);

        return NULL;

    }

    if (strncmp(bname + len - (sizeof(PLUGIN_EXTENSION) - 1),

                PLUGIN_EXTENSION, sizeof(PLUGIN_EXTENSION) - 1) != 0) {

        flb_error("[plugin] invalid plugin extension: %s", bname);

        return NULL;

    }

    /* Get the expected structure name */

    name = flb_malloc(len + (sizeof(PLUGIN_STRUCT_SUFFIX) - 1) + 1);

    if (!name) {

        flb_errno();

        return NULL;

    }

    /* Name without prefix */

    p = bname + (sizeof(PLUGIN_PREFIX) - 1);

    o_len = len - (sizeof(PLUGIN_PREFIX) - 1) - (sizeof(PLUGIN_EXTENSION) - 1);

    memcpy(name, p, o_len);

    name[o_len] = '\0';

    /* Validate expected plugin type */

    if (is_input(name) == FLB_FALSE &&

        is_processor(name) == FLB_FALSE &&

        is_filter(name) == FLB_FALSE &&

        is_output(name) == FLB_FALSE) {

        flb_error("[plugin] invalid plugin type: %s", name);

        flb_free(name);

        return NULL;

    }

    /* Append struct suffix */

    p = name + o_len;

    memcpy(p, PLUGIN_STRUCT_SUFFIX, sizeof(PLUGIN_STRUCT_SUFFIX) - 1);

    o_len += sizeof(PLUGIN_STRUCT_SUFFIX) - 1;

    name[o_len] = '\0';

    return name;

}

static void destroy_plugin(struct flb_plugin *plugin)

{

    flb_sds_destroy(plugin->path);

    dlclose(plugin->dso_handle);

    mk_list_del(&plugin->_head);

    flb_free(plugin);

}

/* Creates the global plugin context for 'dynamic plugins' */

struct flb_plugins *flb_plugin_create()

{

    struct flb_plugins *ctx;

    ctx = flb_malloc(sizeof(struct flb_plugins));

    if (!ctx) {

        flb_errno();

        return NULL;

    }

    mk_list_init(&ctx->input);

    mk_list_init(&ctx->processor);

    mk_list_init(&ctx->filter);

    mk_list_init(&ctx->output);

    return ctx;

}

int flb_plugin_load(char *path, struct flb_plugins *ctx,

                    struct flb_config *config)

{

    int type = -1;

    void *dso_handle;

    void *symbol = NULL;

    char *plugin_stname;

    struct flb_plugin *plugin;

    struct flb_input_plugin *input;

    struct flb_processor_plugin *processor;

    struct flb_filter_plugin *filter;

    struct flb_output_plugin *output;

    /* Open the shared object file: dlopen(3) */

    dso_handle = get_handle(path);

    if (!dso_handle) {

        return -1;

    }

    /*

     * Based on the shared object file name, compose the expected

     * registration structure name.

     */

    plugin_stname = path_to_plugin_name(path);

    if (!plugin_stname) {

        dlclose(dso_handle);

        return -1;

    }

    /* Get the registration structure */

    symbol = load_symbol(dso_handle, plugin_stname);

    if (!symbol) {

        flb_error("[plugin] cannot load plugin '%s', "

                  "registration structure is missing '%s'",

                  path, plugin_stname);

        flb_free(plugin_stname);

        dlclose(dso_handle);

        return -1;

    }

    /* Detect plugin type and link it to the main context */

    if (is_input(plugin_stname) == FLB_TRUE) {

        type = FLB_PLUGIN_INPUT;

        input = flb_malloc(sizeof(struct flb_input_plugin));

        if (!input) {

            flb_errno();

            flb_free(plugin_stname);

            dlclose(dso_handle);

            return -1;

        }

        memcpy(input, symbol, sizeof(struct flb_input_plugin));

        mk_list_add(&input->_head, &config->in_plugins);

    }

    else if (is_processor(plugin_stname) == FLB_TRUE) {

        type = FLB_PLUGIN_PROCESSOR;

        processor = flb_malloc(sizeof(struct flb_processor_plugin));

        if (processor == NULL) {

            flb_errno();

            flb_free(plugin_stname);

            dlclose(dso_handle);

            return -1;

        }

        memcpy(processor, symbol, sizeof(struct flb_processor_plugin));

        mk_list_add(&processor->_head, &config->processor_plugins);

    }

    else if (is_filter(plugin_stname) == FLB_TRUE) {

        type = FLB_PLUGIN_FILTER;

        filter = flb_malloc(sizeof(struct flb_filter_plugin));

        if (!filter) {

            flb_errno();

            flb_free(plugin_stname);

            dlclose(dso_handle);

            return -1;

        }

        memcpy(filter, symbol, sizeof(struct flb_filter_plugin));

        mk_list_add(&filter->_head, &config->filter_plugins);

    }

    else if (is_output(plugin_stname) == FLB_TRUE) {

        type = FLB_PLUGIN_OUTPUT;

        output = flb_malloc(sizeof(struct flb_output_plugin));

        if (!output) {

            flb_errno();

            flb_free(plugin_stname);

            dlclose(dso_handle);

            return -1;

        }

        memcpy(output, symbol, sizeof(struct flb_output_plugin));

        mk_list_add(&output->_head, &config->out_plugins);

    }

    flb_free(plugin_stname);

    if (type == -1) {

        flb_error("[plugin] plugin type not defined on '%s'", path);

        dlclose(dso_handle);

        return -1;

    }

    /* Create plugin context (internal reference only) */

    plugin = flb_malloc(sizeof(struct flb_plugin));

    if (!plugin) {

        flb_errno();

        dlclose(dso_handle);

        return -1;

    }

    plugin->type = type;

    plugin->path = flb_sds_create(path);

    plugin->dso_handle = dso_handle;

    /* Link by type to the plugins parent context */

    if (type == FLB_PLUGIN_INPUT) {

        mk_list_add(&plugin->_head, &ctx->input);

    }

    else if (type == FLB_PLUGIN_PROCESSOR) {

        mk_list_add(&plugin->_head, &ctx->processor);

    }

    else if (type == FLB_PLUGIN_FILTER) {

        mk_list_add(&plugin->_head, &ctx->filter);

    }

    else if (type == FLB_PLUGIN_OUTPUT) {

        mk_list_add(&plugin->_head, &ctx->output);

    }

    return 0;

}

int flb_plugin_load_router(char *path, struct flb_config *config)

{

    int ret = -1;

    char *bname;

    bname = basename(path);

    /* Is this a DSO C plugin ? */

    if (strncmp(bname, PLUGIN_PREFIX, sizeof(PLUGIN_PREFIX) - 1) == 0) {

        ret = flb_plugin_load(path, config->dso_plugins, config);

        if (ret == -1) {

            flb_error("[plugin] error loading DSO C plugin: %s", path);

            return -1;

        }

    }

    else {

#ifdef FLB_HAVE_PROXY_GO

        if (flb_plugin_proxy_create(path, 0, config) == NULL) {

            flb_error("[plugin] error loading proxy plugin: %s", path);

            return -1;

        }

#else

        flb_error("[plugin] unsupported plugin type at: %s", path);

        return -1;

#endif

    }

    return 0;

}

int flb_plugin_load_config_format(struct flb_cf *cf, struct flb_config *config)

{

    int ret;

    struct mk_list *head;

    struct cfl_list *head_e;

    struct flb_cf_section *section;

    struct cfl_kvpair *entry;

    /* read all 'plugins' sections */

    mk_list_foreach(head, &cf->plugins) {

        section = mk_list_entry(head, struct flb_cf_section, _head_section);

        cfl_list_foreach(head_e, &section->properties->list) {

            entry = cfl_list_entry(head_e, struct cfl_kvpair, _head);

            /* Load plugin with router function */

            ret = flb_plugin_load_router(entry->key, config);

            if (ret == -1) {

                flb_cf_destroy(cf);

                return -1;

            }

        }

    }

    return 0;

}

/* Load plugins from a configuration file */

int flb_plugin_load_config_file(const char *file, struct flb_config *config)

{

    int ret;

    char tmp[PATH_MAX + 1];

    char *cfg = NULL;

    struct mk_list *head;

    struct cfl_list *head_e;

    struct stat st;

    struct flb_cf *cf;

    struct flb_cf_section *section;

    struct cfl_kvpair *entry;

#ifndef FLB_HAVE_STATIC_CONF

    ret = stat(file, &st);

    if (ret == -1 && errno == ENOENT) {

        /* Try to resolve the real path (if exists) */

        if (file[0] == '/') {

            flb_utils_error(FLB_ERR_CFG_PLUGIN_FILE);

            return -1;

        }

        if (config->conf_path) {

            snprintf(tmp, PATH_MAX, "%s%s", config->conf_path, file);

            cfg = tmp;

        }

    }

    else {

        cfg = (char *) file;

    }

    flb_debug("[plugin] opening configuration file %s", cfg);

    cf = flb_cf_create_from_file(NULL, cfg);

#else

    cf = flb_config_static_open(file);

#endif

    if (!cf) {

        return -1;

    }

    if (cf->format == FLB_CF_FLUENTBIT) {

        /* (classic mode) read all 'plugins' sections */

        mk_list_foreach(head, &cf->sections) {

            section = mk_list_entry(head, struct flb_cf_section, _head);

            if (strcasecmp(section->name, "plugins") != 0) {

                continue;

            }

            cfl_list_foreach(head_e, &section->properties->list) {

                entry = cfl_list_entry(head_e, struct cfl_kvpair, _head);

                if (strcasecmp(entry->key, "path") != 0) {

                    continue;

                }

                /* Load plugin with router function */

                ret = flb_plugin_load_router(entry->val->data.as_string, config);

                if (ret == -1) {

                    flb_cf_destroy(cf);

                    return -1;

                }

            }

        }

    }

#ifdef FLB_HAVE_LIBYAML

    else if (cf->format == FLB_CF_YAML) {

        /*

         * pass to the config_format loader also in case some Yaml have been included in

         * the service section through the option 'plugins_file'

         */

        ret = flb_plugin_load_config_format(cf, config);

        if (ret == -1) {

            return -1;

        }

    }

#endif

    flb_cf_destroy(cf);

    return 0;

}

/* Destroy plugin context */

void flb_plugin_destroy(struct flb_plugins *ctx)

{

    struct mk_list *tmp;

    struct mk_list *head;

    struct flb_plugin *plugin;

    mk_list_foreach_safe(head, tmp, &ctx->input) {

        plugin = mk_list_entry(head, struct flb_plugin, _head);

        destroy_plugin(plugin);

    }

    mk_list_foreach_safe(head, tmp, &ctx->processor) {

        plugin = mk_list_entry(head, struct flb_plugin, _head);

        destroy_plugin(plugin);

    }

    mk_list_foreach_safe(head, tmp, &ctx->filter) {

        plugin = mk_list_entry(head, struct flb_plugin, _head);

        destroy_plugin(plugin);

    }

    mk_list_foreach_safe(head, tmp, &ctx->output) {

        plugin = mk_list_entry(head, struct flb_plugin, _head);

        destroy_plugin(plugin);

    }

    flb_free(ctx);

}