mpd/src/command.c

/*
 * Copyright (C) 2003-2012 The Music Player Daemon Project
 * http://www.musicpd.org
 *
 * 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 "config.h"
#include "command.h"
#include "QueueCommands.hxx"
#include "PlayerCommands.hxx"
#include "PlaylistCommands.hxx"
#include "DatabaseCommands.hxx"
#include "OutputCommands.hxx"
#include "StickerCommands.hxx"
#include "MessageCommands.hxx"
#include "OtherCommands.hxx"
#include "CommandError.h"
#include "protocol/argparser.h"
#include "protocol/result.h"
#include "permission.h"
#include "tokenizer.h"
#include "tag.h"
#include "client.h"

#ifdef ENABLE_SQLITE
#include "sticker.h"
#endif

#include <assert.h>
#include <string.h>

/*
 * The most we ever use is for search/find, and that limits it to the
 * number of tags we can have.  Add one for the command, and one extra
 * to catch errors clients may send us
 */
#define COMMAND_ARGV_MAX	(2+(TAG_NUM_OF_ITEM_TYPES*2))

/* if min: -1 don't check args *
 * if max: -1 no max args      */
struct command {
	const char *cmd;
	unsigned permission;
	int min;
	int max;
	enum command_return (*handler)(struct client *client, int argc, char **argv);
};

/* don't be fooled, this is the command handler for "commands" command */
static enum command_return
handle_commands(struct client *client,
		G_GNUC_UNUSED int argc, G_GNUC_UNUSED char *argv[]);

static enum command_return
handle_not_commands(struct client *client,
		    G_GNUC_UNUSED int argc, G_GNUC_UNUSED char *argv[]);

/**
 * The command registry.
 *
 * This array must be sorted!
 */
static const struct command commands[] = {
	{ "add", PERMISSION_ADD, 1, 1, handle_add },
	{ "addid", PERMISSION_ADD, 1, 2, handle_addid },
	{ "channels", PERMISSION_READ, 0, 0, handle_channels },
	{ "clear", PERMISSION_CONTROL, 0, 0, handle_clear },
	{ "clearerror", PERMISSION_CONTROL, 0, 0, handle_clearerror },
	{ "close", PERMISSION_NONE, -1, -1, handle_close },
	{ "commands", PERMISSION_NONE, 0, 0, handle_commands },
	{ "config", PERMISSION_ADMIN, 0, 0, handle_config },
	{ "consume", PERMISSION_CONTROL, 1, 1, handle_consume },
	{ "count", PERMISSION_READ, 2, -1, handle_count },
	{ "crossfade", PERMISSION_CONTROL, 1, 1, handle_crossfade },
	{ "currentsong", PERMISSION_READ, 0, 0, handle_currentsong },
	{ "decoders", PERMISSION_READ, 0, 0, handle_decoders },
	{ "delete", PERMISSION_CONTROL, 1, 1, handle_delete },
	{ "deleteid", PERMISSION_CONTROL, 1, 1, handle_deleteid },
	{ "disableoutput", PERMISSION_ADMIN, 1, 1, handle_disableoutput },
	{ "enableoutput", PERMISSION_ADMIN, 1, 1, handle_enableoutput },
	{ "find", PERMISSION_READ, 2, -1, handle_find },
	{ "findadd", PERMISSION_READ, 2, -1, handle_findadd},
	{ "idle", PERMISSION_READ, 0, -1, handle_idle },
	{ "kill", PERMISSION_ADMIN, -1, -1, handle_kill },
	{ "list", PERMISSION_READ, 1, -1, handle_list },
	{ "listall", PERMISSION_READ, 0, 1, handle_listall },
	{ "listallinfo", PERMISSION_READ, 0, 1, handle_listallinfo },
	{ "listplaylist", PERMISSION_READ, 1, 1, handle_listplaylist },
	{ "listplaylistinfo", PERMISSION_READ, 1, 1, handle_listplaylistinfo },
	{ "listplaylists", PERMISSION_READ, 0, 0, handle_listplaylists },
	{ "load", PERMISSION_ADD, 1, 2, handle_load },
	{ "lsinfo", PERMISSION_READ, 0, 1, handle_lsinfo },
	{ "mixrampdb", PERMISSION_CONTROL, 1, 1, handle_mixrampdb },
	{ "mixrampdelay", PERMISSION_CONTROL, 1, 1, handle_mixrampdelay },
	{ "move", PERMISSION_CONTROL, 2, 2, handle_move },
	{ "moveid", PERMISSION_CONTROL, 2, 2, handle_moveid },
	{ "next", PERMISSION_CONTROL, 0, 0, handle_next },
	{ "notcommands", PERMISSION_NONE, 0, 0, handle_not_commands },
	{ "outputs", PERMISSION_READ, 0, 0, handle_devices },
	{ "password", PERMISSION_NONE, 1, 1, handle_password },
	{ "pause", PERMISSION_CONTROL, 0, 1, handle_pause },
	{ "ping", PERMISSION_NONE, 0, 0, handle_ping },
	{ "play", PERMISSION_CONTROL, 0, 1, handle_play },
	{ "playid", PERMISSION_CONTROL, 0, 1, handle_playid },
	{ "playlist", PERMISSION_READ, 0, 0, handle_playlist },
	{ "playlistadd", PERMISSION_CONTROL, 2, 2, handle_playlistadd },
	{ "playlistclear", PERMISSION_CONTROL, 1, 1, handle_playlistclear },
	{ "playlistdelete", PERMISSION_CONTROL, 2, 2, handle_playlistdelete },
	{ "playlistfind", PERMISSION_READ, 2, -1, handle_playlistfind },
	{ "playlistid", PERMISSION_READ, 0, 1, handle_playlistid },
	{ "playlistinfo", PERMISSION_READ, 0, 1, handle_playlistinfo },
	{ "playlistmove", PERMISSION_CONTROL, 3, 3, handle_playlistmove },
	{ "playlistsearch", PERMISSION_READ, 2, -1, handle_playlistsearch },
	{ "plchanges", PERMISSION_READ, 1, 1, handle_plchanges },
	{ "plchangesposid", PERMISSION_READ, 1, 1, handle_plchangesposid },
	{ "previous", PERMISSION_CONTROL, 0, 0, handle_previous },
	{ "prio", PERMISSION_CONTROL, 2, -1, handle_prio },
	{ "prioid", PERMISSION_CONTROL, 2, -1, handle_prioid },
	{ "random", PERMISSION_CONTROL, 1, 1, handle_random },
	{ "readmessages", PERMISSION_READ, 0, 0, handle_read_messages },
	{ "rename", PERMISSION_CONTROL, 2, 2, handle_rename },
	{ "repeat", PERMISSION_CONTROL, 1, 1, handle_repeat },
	{ "replay_gain_mode", PERMISSION_CONTROL, 1, 1,
	  handle_replay_gain_mode },
	{ "replay_gain_status", PERMISSION_READ, 0, 0,
	  handle_replay_gain_status },
	{ "rescan", PERMISSION_CONTROL, 0, 1, handle_rescan },
	{ "rm", PERMISSION_CONTROL, 1, 1, handle_rm },
	{ "save", PERMISSION_CONTROL, 1, 1, handle_save },
	{ "search", PERMISSION_READ, 2, -1, handle_search },
	{ "searchadd", PERMISSION_ADD, 2, -1, handle_searchadd },
	{ "searchaddpl", PERMISSION_CONTROL, 3, -1, handle_searchaddpl },
	{ "seek", PERMISSION_CONTROL, 2, 2, handle_seek },
	{ "seekcur", PERMISSION_CONTROL, 1, 1, handle_seekcur },
	{ "seekid", PERMISSION_CONTROL, 2, 2, handle_seekid },
	{ "sendmessage", PERMISSION_CONTROL, 2, 2, handle_send_message },
	{ "setvol", PERMISSION_CONTROL, 1, 1, handle_setvol },
	{ "shuffle", PERMISSION_CONTROL, 0, 1, handle_shuffle },
	{ "single", PERMISSION_CONTROL, 1, 1, handle_single },
	{ "stats", PERMISSION_READ, 0, 0, handle_stats },
	{ "status", PERMISSION_READ, 0, 0, handle_status },
#ifdef ENABLE_SQLITE
	{ "sticker", PERMISSION_ADMIN, 3, -1, handle_sticker },
#endif
	{ "stop", PERMISSION_CONTROL, 0, 0, handle_stop },
	{ "subscribe", PERMISSION_READ, 1, 1, handle_subscribe },
	{ "swap", PERMISSION_CONTROL, 2, 2, handle_swap },
	{ "swapid", PERMISSION_CONTROL, 2, 2, handle_swapid },
	{ "tagtypes", PERMISSION_READ, 0, 0, handle_tagtypes },
	{ "unsubscribe", PERMISSION_READ, 1, 1, handle_unsubscribe },
	{ "update", PERMISSION_CONTROL, 0, 1, handle_update },
	{ "urlhandlers", PERMISSION_READ, 0, 0, handle_urlhandlers },
};

static const unsigned num_commands = sizeof(commands) / sizeof(commands[0]);

static bool
command_available(G_GNUC_UNUSED const struct command *cmd)
{
#ifdef ENABLE_SQLITE
	if (strcmp(cmd->cmd, "sticker") == 0)
		return sticker_enabled();
#endif

	return true;
}

/* don't be fooled, this is the command handler for "commands" command */
static enum command_return
handle_commands(struct client *client,
		G_GNUC_UNUSED int argc, G_GNUC_UNUSED char *argv[])
{
	const unsigned permission = client_get_permission(client);
	const struct command *cmd;

	for (unsigned i = 0; i < num_commands; ++i) {
		cmd = &commands[i];

		if (cmd->permission == (permission & cmd->permission) &&
		    command_available(cmd))
			client_printf(client, "command: %s\n", cmd->cmd);
	}

	return COMMAND_RETURN_OK;
}

static enum command_return
handle_not_commands(struct client *client,
		    G_GNUC_UNUSED int argc, G_GNUC_UNUSED char *argv[])
{
	const unsigned permission = client_get_permission(client);
	const struct command *cmd;

	for (unsigned i = 0; i < num_commands; ++i) {
		cmd = &commands[i];

		if (cmd->permission != (permission & cmd->permission))
			client_printf(client, "command: %s\n", cmd->cmd);
	}

	return COMMAND_RETURN_OK;
}

void command_init(void)
{
#ifndef NDEBUG
	/* ensure that the command list is sorted */
	for (unsigned i = 0; i < num_commands - 1; ++i)
		assert(strcmp(commands[i].cmd, commands[i + 1].cmd) < 0);
#endif
}

void command_finish(void)
{
}

static const struct command *
command_lookup(const char *name)
{
	unsigned a = 0, b = num_commands, i;
	int cmp;

	/* binary search */
	do {
		i = (a + b) / 2;

		cmp = strcmp(name, commands[i].cmd);
		if (cmp == 0)
			return &commands[i];
		else if (cmp < 0)
			b = i;
		else if (cmp > 0)
			a = i + 1;
	} while (a < b);

	return NULL;
}

static bool
command_check_request(const struct command *cmd, struct client *client,
		      unsigned permission, int argc, char *argv[])
{
	int min = cmd->min + 1;
	int max = cmd->max + 1;

	if (cmd->permission != (permission & cmd->permission)) {
		if (client != NULL)
			command_error(client, ACK_ERROR_PERMISSION,
				      "you don't have permission for \"%s\"",
				      cmd->cmd);
		return false;
	}

	if (min == 0)
		return true;

	if (min == max && max != argc) {
		if (client != NULL)
			command_error(client, ACK_ERROR_ARG,
				      "wrong number of arguments for \"%s\"",
				      argv[0]);
		return false;
	} else if (argc < min) {
		if (client != NULL)
			command_error(client, ACK_ERROR_ARG,
				      "too few arguments for \"%s\"", argv[0]);
		return false;
	} else if (argc > max && max /* != 0 */ ) {
		if (client != NULL)
			command_error(client, ACK_ERROR_ARG,
				      "too many arguments for \"%s\"", argv[0]);
		return false;
	} else
		return true;
}

static const struct command *
command_checked_lookup(struct client *client, unsigned permission,
		       int argc, char *argv[])
{
	const struct command *cmd;

	current_command = "";

	if (argc == 0)
		return NULL;

	cmd = command_lookup(argv[0]);
	if (cmd == NULL) {
		if (client != NULL)
			command_error(client, ACK_ERROR_UNKNOWN,
				      "unknown command \"%s\"", argv[0]);
		return NULL;
	}

	current_command = cmd->cmd;

	if (!command_check_request(cmd, client, permission, argc, argv))
		return NULL;

	return cmd;
}

enum command_return
command_process(struct client *client, unsigned num, char *line)
{
	GError *error = NULL;
	int argc;
	char *argv[COMMAND_ARGV_MAX] = { NULL };
	const struct command *cmd;
	enum command_return ret = COMMAND_RETURN_ERROR;

	command_list_num = num;

	/* get the command name (first word on the line) */

	argv[0] = tokenizer_next_word(&line, &error);
	if (argv[0] == NULL) {
		current_command = "";
		if (*line == 0)
			command_error(client, ACK_ERROR_UNKNOWN,
				      "No command given");
		else {
			command_error(client, ACK_ERROR_UNKNOWN,
				      "%s", error->message);
			g_error_free(error);
		}
		current_command = NULL;

		return COMMAND_RETURN_ERROR;
	}

	argc = 1;

	/* now parse the arguments (quoted or unquoted) */

	while (argc < (int)G_N_ELEMENTS(argv) &&
	       (argv[argc] =
		tokenizer_next_param(&line, &error)) != NULL)
		++argc;

	/* some error checks; we have to set current_command because
	   command_error() expects it to be set */

	current_command = argv[0];

	if (argc >= (int)G_N_ELEMENTS(argv)) {
		command_error(client, ACK_ERROR_ARG, "Too many arguments");
		current_command = NULL;
		return COMMAND_RETURN_ERROR;
	}

	if (*line != 0) {
		command_error(client, ACK_ERROR_ARG,
			      "%s", error->message);
		current_command = NULL;
		g_error_free(error);
		return COMMAND_RETURN_ERROR;
	}

	/* look up and invoke the command handler */

	cmd = command_checked_lookup(client, client_get_permission(client),
				     argc, argv);
	if (cmd)
		ret = cmd->handler(client, argc, argv);

	current_command = NULL;
	command_list_num = 0;

	return ret;
}