res_clialiases.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2008, Digium, Inc.
 *
 * Joshua Colp <[email protected]>
 *
 * 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 CLI Aliases
 *
 * \author\verbatim Joshua Colp <[email protected]> \endverbatim
 *
 * This module provides the capability to create aliases to other
 * CLI commands.
 */

/*! \li \ref res_clialiases.c uses the configuration file \ref cli_aliases.conf
 * \addtogroup configuration_file Configuration Files
 */

/*!
 * \page cli_aliases.conf cli_aliases.conf
 * \verbinclude cli_aliases.conf.sample
 */

/*** MODULEINFO
   <support_level>core</support_level>
 ***/

#include "asterisk.h"

#include "asterisk/module.h"
#include "asterisk/config.h"
#include "asterisk/cli.h"
#include "asterisk/astobj2.h"

/*! Maximum number of buckets for CLI aliases */
#define MAX_ALIAS_BUCKETS 53

/*! Configuration file used for this application */
static const char config_file[] = "cli_aliases.conf";

struct cli_alias {
   struct ast_cli_entry cli_entry; /*!< Actual CLI structure used for this alias */
   char *alias;                    /*!< CLI Alias */
   char *real_cmd;                 /*!< Actual CLI command it is aliased to */
};

static struct ao2_container *cli_aliases;

/*! \brief Hashing function used for aliases */
static int alias_hash_cb(const void *obj, const int flags)
{
   const struct cli_alias *alias = obj;
   return ast_str_hash(alias->cli_entry.command);
}

/*! \brief Comparison function used for aliases */
static int alias_cmp_cb(void *obj, void *arg, int flags)
{
   const struct cli_alias *alias0 = obj, *alias1 = arg;

   return (alias0->cli_entry.command == alias1->cli_entry.command ? CMP_MATCH | CMP_STOP : 0);
}

/*! \brief Callback for unregistering an alias */
static int alias_unregister_cb(void *obj, void *arg, int flags)
{
   struct cli_alias *alias = obj;

   /* Unregister the CLI entry from the core */
   ast_cli_unregister(&alias->cli_entry);

   /* We can determine if this worked or not by looking at the cli_entry itself */
   return !alias->cli_entry.command ? CMP_MATCH : 0;
}

/*! \brief Callback for finding an alias based on name */
static int alias_name_cb(void *obj, void *arg, int flags)
{
   struct cli_alias *alias = obj;
   char *name = arg;

   return !strcmp(alias->alias, name) ? CMP_MATCH | CMP_STOP : 0;
}

/*! \brief Function which passes through an aliased CLI command to the real one */
static char *cli_alias_passthrough(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   struct cli_alias *alias;
   struct cli_alias tmp = {
      .cli_entry.command = e->command,
   };
   char *generator = NULL;
   const char *line;

   /* Try to find the alias based on the CLI entry */
   if (!(alias = ao2_find(cli_aliases, &tmp, OBJ_POINTER))) {
      return 0;
   }

   switch (cmd) {
   case CLI_INIT:
      ao2_ref(alias, -1);
      return NULL;
   case CLI_GENERATE:
      line = a->line;
      line += (strlen(alias->alias));
      if (strncasecmp(alias->alias, alias->real_cmd, strlen(alias->alias))) {
         struct ast_str *real_cmd = ast_str_alloca(strlen(alias->real_cmd) + strlen(line) + 1);
         ast_str_append(&real_cmd, 0, "%s%s", alias->real_cmd, line);
         generator = ast_cli_generator(ast_str_buffer(real_cmd), a->word, a->n);
      }
      ao2_ref(alias, -1);
      return generator;
   }

   /* If they gave us extra arguments we need to construct a string to pass in */
   if (a->argc != e->args) {
      struct ast_str *real_cmd = ast_str_alloca(2048);
      int i;

      ast_str_append(&real_cmd, 0, "%s", alias->real_cmd);

      /* Add the additional arguments that have been passed in */
      for (i = e->args + 1; i <= a->argc; i++) {
         ast_str_append(&real_cmd, 0, " %s", a->argv[i - 1]);
      }

      ast_cli_command(a->fd, ast_str_buffer(real_cmd));
   } else {
      ast_cli_command(a->fd, alias->real_cmd);
   }

   ao2_ref(alias, -1);

   return CLI_SUCCESS;
}

/*! \brief CLI Command to display CLI Aliases */
static char *alias_show(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
#define FORMAT "%-50.50s %-50.50s\n"
   struct cli_alias *alias;
   struct ao2_iterator i;

   switch (cmd) {
   case CLI_INIT:
      e->command = "cli show aliases";
      e->usage =
         "Usage: cli show aliases\n"
         "       Displays a list of aliased CLI commands.\n";
      return NULL;
   case CLI_GENERATE:
      return NULL;
   }

   ast_cli(a->fd, FORMAT, "Alias Command", "Real Command");

   i = ao2_iterator_init(cli_aliases, 0);
   for (; (alias = ao2_iterator_next(&i)); ao2_ref(alias, -1)) {
      ast_cli(a->fd, FORMAT, alias->alias, alias->real_cmd);
   }
   ao2_iterator_destroy(&i);

   return CLI_SUCCESS;
#undef FORMAT
}

/*! \brief CLI commands to interact with things */
static struct ast_cli_entry cli_alias[] = {
   AST_CLI_DEFINE(alias_show, "Show CLI command aliases"),
};

/*! \brief Function called to load or reload the configuration file */
static void load_config(int reload)
{
   struct ast_config *cfg = NULL;
   struct ast_flags config_flags = { reload ? CONFIG_FLAG_FILEUNCHANGED : 0 };
   struct cli_alias *alias;
   struct ast_variable *v, *v1;

   if (!(cfg = ast_config_load(config_file, config_flags)) || cfg == CONFIG_STATUS_FILEINVALID) {
      ast_log(LOG_ERROR, "res_clialiases configuration file '%s' not found\n", config_file);
      return;
   } else if (cfg == CONFIG_STATUS_FILEUNCHANGED) {
      return;
   }

   /* Destroy any existing CLI aliases */
   if (reload) {
      ao2_callback(cli_aliases, OBJ_UNLINK | OBJ_NODATA | OBJ_MULTIPLE, alias_unregister_cb, NULL);
   }

   for (v = ast_variable_browse(cfg, "general"); v; v = v->next) {
      if (strcmp(v->name, "template")) {
         ast_log(LOG_WARNING, "%s is not a correct option in [%s]\n", v->name, "general");
         continue;
      }
      /* Read in those there CLI aliases */
      for (v1 = ast_variable_browse(cfg, v->value); v1; v1 = v1->next) {
         struct cli_alias *existing = ao2_callback(cli_aliases, 0, alias_name_cb, (char*)v1->name);

         if (existing) {
            ast_log(LOG_WARNING, "Alias '%s' could not be unregistered and has been retained\n",
               existing->alias);
            ao2_ref(existing, -1);
            continue;
         }

         if (!(alias = ao2_alloc((sizeof(*alias) + strlen(v1->name) + strlen(v1->value) + 2), NULL))) {
            continue;
         }
         alias->alias = ((char *) alias) + sizeof(*alias);
         alias->real_cmd = ((char *) alias->alias) + strlen(v1->name) + 1;
         strcpy(alias->alias, v1->name);
         strcpy(alias->real_cmd, v1->value);
         alias->cli_entry.handler = cli_alias_passthrough;
         alias->cli_entry.command = alias->alias;
         alias->cli_entry.usage = "Aliased CLI Command\n";

         if (ast_cli_register(&alias->cli_entry)) {
            ao2_ref(alias, -1);
            continue;
         }
         ao2_link(cli_aliases, alias);
         ast_verb(2, "Aliased CLI command '%s' to '%s'\n", v1->name, v1->value);
         ao2_ref(alias, -1);
      }
   }

   ast_config_destroy(cfg);

   return;
}

/*! \brief Function called to reload the module */
static int reload_module(void)
{
   load_config(1);
   return 0;
}

/*! \brief Function called to unload the module */
static int unload_module(void)
{
   ao2_callback(cli_aliases, OBJ_UNLINK | OBJ_NODATA | OBJ_MULTIPLE, alias_unregister_cb, NULL);

   if (ao2_container_count(cli_aliases)) {
      ast_log(LOG_ERROR, "Could not unregister all CLI aliases\n");
      return -1;
   }

   ao2_ref(cli_aliases, -1);

   ast_cli_unregister_multiple(cli_alias, ARRAY_LEN(cli_alias));

   return 0;
}

/*!
 * \brief Load the module
 *
 * Module loading including tests for configuration or dependencies.
 * This function can return AST_MODULE_LOAD_FAILURE, AST_MODULE_LOAD_DECLINE,
 * or AST_MODULE_LOAD_SUCCESS. If a dependency or environment variable fails
 * tests return AST_MODULE_LOAD_FAILURE. If the module can not load the
 * configuration file or other non-critical problem return
 * AST_MODULE_LOAD_DECLINE. On success return AST_MODULE_LOAD_SUCCESS.
 */
static int load_module(void)
{
   cli_aliases = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0,
      MAX_ALIAS_BUCKETS, alias_hash_cb, NULL, alias_cmp_cb);
   if (!cli_aliases) {
      return AST_MODULE_LOAD_DECLINE;
   }

   load_config(0);

   ast_cli_register_multiple(cli_alias, ARRAY_LEN(cli_alias));

   return AST_MODULE_LOAD_SUCCESS;
}

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_DEFAULT, "CLI Aliases",
   .support_level = AST_MODULE_SUPPORT_CORE,
   .load = load_module,
   .unload = unload_module,
   .reload = reload_module,
);