irc_commands.c

/********************************************************************\
  * BitlBee -- An IRC to other IM-networks gateway                     *
  *                                                                    *
  * Copyright 2002-2012 Wilmer van der Gaast and others                *
  \********************************************************************/

/* IRC commands                                                         */

/*
  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 with
  the Debian GNU/Linux distribution in /usr/share/common-licenses/GPL;
  if not, write to the Free Software Foundation, Inc., 51 Franklin St.,
  Fifth Floor, Boston, MA  02110-1301  USA
*/

#define BITLBEE_CORE
#include "bitlbee.h"
#include "canohost.h"
#include "help.h"
#include "ipc.h"
#include "base64.h"

static void irc_cmd_pass(irc_t *irc, char **cmd)
{
	if (irc->status & USTATUS_LOGGED_IN) {
		char *send_cmd[] = { "identify", cmd[1], NULL };

		/* We're already logged in, this client seems to send the PASS
		   command last. (Possibly it won't send it at all if it turns
		   out we don't require it, which will break this feature.)
		   Try to identify using the given password. */
		root_command(irc, send_cmd);
		return;
	}
	/* Handling in pre-logged-in state, first see if this server is
	   password-protected: */
	else if (global.conf->auth_pass &&
	         (strncmp(global.conf->auth_pass, "md5:", 4) == 0 ?
	          md5_verify_password(cmd[1], global.conf->auth_pass + 4) == 0 :
	          strcmp(cmd[1], global.conf->auth_pass) == 0)) {
		irc->status |= USTATUS_AUTHORIZED;
		irc_check_login(irc);
	} else if (global.conf->auth_pass) {
		irc_send_num(irc, 464, ":Incorrect password");
	} else {
		/* Remember the password and try to identify after USER/NICK. */
		irc_setpass(irc, cmd[1]);
		irc_check_login(irc);
	}
}

/* http://www.haproxy.org/download/1.8/doc/proxy-protocol.txt

   This isn't actually IRC, it's used by for example stunnel4 to indicate
   the origin of the secured counterpart of the connection. It'll go wrong
   with arguments starting with : like for example "::1" but I guess I'm
   okay with that. */
static void irc_cmd_proxy(irc_t *irc, char **cmd)
{
	struct addrinfo hints, *ai;
	struct sockaddr_storage sock;
	socklen_t socklen = sizeof(sock);

	if (getpeername(irc->fd, (struct sockaddr*) &sock, &socklen) != 0) {
		return;
	}

	ipv64_normalise_mapped(&sock, &socklen);

	/* Only accept PROXY "command" on localhost sockets. */
	if (!((sock.ss_family == AF_INET &&
	       ntohl(((struct sockaddr_in*)&sock)->sin_addr.s_addr) == INADDR_LOOPBACK) ||
	      (sock.ss_family == AF_INET6 &&
	       IN6_IS_ADDR_LOOPBACK(&((struct sockaddr_in6*)&sock)->sin6_addr)))) {
		return;
	}

	/* And only once. Do this with a pretty dumb regex-match for
	   now, maybe better to use some sort of flag.. */
	if (!g_regex_match_simple("^(ip6-)?localhost(.(localdomain.?)?)?$", irc->user->host, 0, 0)) {
		return;
	}
	
	memset(&hints, 0, sizeof(hints));
	hints.ai_flags = AI_NUMERICHOST;
	if (getaddrinfo(cmd[2], NULL, &hints, &ai) != 0) {
		return;
	}
	
	irc_set_hosts(irc, ai->ai_addr, ai->ai_addrlen);
	freeaddrinfo(ai);
}

static gboolean irc_sasl_plain_parse(char *input, char **user, char **pass)
{
	int i, part, len;
	guint8 *decoded;
	char *parts[3];

	/* bitlbee's base64_decode wrapper adds an extra null terminator at the end */
	len = base64_decode(input, &decoded);

	/* this loop splits the decoded string into the parts array, like this:
	   "username\0username\0password" -> {"username", "username", "password"} */

	for (i = 0, part = 0; i < len && part < 3; part++) {
		/* set each of parts[] to point to the beginning of a string */
		parts[part] = (char *) decoded + i;

		/* move the cursor forward to the next null terminator*/
		i += strlen(parts[part]) + 1;
	}

	/* sanity checks */
	if (part != 3 || i != (len + 1) || (parts[0][0] && strcmp(parts[0], parts[1]) != 0)) {
		g_free(decoded);
		return FALSE;
	} else {
		*user = g_strdup(parts[1]);
		*pass = g_strdup(parts[2]);
		g_free(decoded);
		return TRUE;
	}
}

static gboolean irc_sasl_check_pass(irc_t *irc, char *user, char *pass)
{
	storage_status_t status;

	/* just check the password here to be able to reply with useful numerics
	 * the actual identification will be handled later */
	status = auth_check_pass(irc, user, pass);

	if (status == STORAGE_OK) {
		if (!irc->user->nick) {
			/* set the nick here so we have it for the following numeric */
			irc->user->nick = g_strdup(user);
		}
		irc_send_num(irc, 900, "%s!%s@%s %s :You are now logged in as %s",
		             irc->user->nick, irc->user->user, irc->user->host,
			     irc->user->nick, irc->user->nick);
		irc_send_num(irc, 903, ":Password accepted");
		return TRUE;

	} else if (status == STORAGE_INVALID_PASSWORD) {
		irc_send_num(irc, 904, ":Incorrect password");
	} else if (status == STORAGE_NO_SUCH_USER) {
		irc_send_num(irc, 904, ":The nick is (probably) not registered");
	} else {
		irc_send_num(irc, 904, ":Unknown SASL authentication error");
	}

	return FALSE;
}

static void irc_cmd_authenticate(irc_t *irc, char **cmd)
{
	/* require the CAP to be enabled, and don't allow authentication before server password */
	if (!(irc->caps & CAP_SASL) ||
	    (global.conf->authmode == AUTHMODE_CLOSED && !(irc->status & USTATUS_AUTHORIZED))) {
		return;
	}

	if (irc->status & USTATUS_SASL_PLAIN_PENDING) {
		char *user, *pass;

		irc->status &= ~USTATUS_SASL_PLAIN_PENDING;

		if (!irc_sasl_plain_parse(cmd[1], &user, &pass)) {
			irc_send_num(irc, 904, ":SASL authentication failed");
			return;
		}

		/* let's not support the nick != user case
		 * if NICK is received after SASL, it will just fail after registration */
		if (user && irc->user->nick && strcmp(user, irc->user->nick) != 0) {
			irc_send_num(irc, 902, ":Your SASL username does not match your nickname");

		} else if (irc_sasl_check_pass(irc, user, pass)) {
			/* and here we do the same thing as the PASS command*/
			if (irc->status & USTATUS_LOGGED_IN) {
				char *send_cmd[] = { "identify", pass, NULL };
				root_command(irc, send_cmd);
			} else {
				/* no check_login here - wait for CAP END */
				irc_setpass(irc, pass);
			}
		}

		g_free(user);
		g_free(pass);

	} else if (irc->status & USTATUS_IDENTIFIED) {
		irc_send_num(irc, 907, ":You have already authenticated");

	} else if (strcmp(cmd[1], "*") == 0) {
		irc_send_num(irc, 906, ":SASL authentication aborted");
		irc->status &= ~USTATUS_SASL_PLAIN_PENDING;

	} else if (g_strcasecmp(cmd[1], "PLAIN") == 0) {
		irc_write(irc, "AUTHENTICATE +");
		irc->status |= USTATUS_SASL_PLAIN_PENDING;

	} else {
		irc_send_num(irc, 908, "PLAIN :is the available SASL mechanism");
		irc_send_num(irc, 904, ":SASL authentication failed");
		irc->status &= ~USTATUS_SASL_PLAIN_PENDING;
	}
}

static void irc_cmd_user(irc_t *irc, char **cmd)
{
	irc->user->user = g_strdup(cmd[1]);
	irc->user->fullname = g_strdup(cmd[4]);

	irc_check_login(irc);
}

static void irc_cmd_nick(irc_t *irc, char **cmd)
{
	irc_user_t *iu;

	if ((iu = irc_user_by_name(irc, cmd[1])) && iu != irc->user) {
		irc_send_num(irc, 433, "%s :This nick is already in use", cmd[1]);
	} else if (!nick_ok(NULL, cmd[1])) {
		/* [SH] Invalid characters. */
		irc_send_num(irc, 432, "%s :This nick contains invalid characters", cmd[1]);
	} else if (irc->status & USTATUS_LOGGED_IN) {
		/* WATCH OUT: iu from the first if reused here to check if the
		   new nickname is the same (other than case, possibly). If it
		   is, no need to reset identify-status. */
		if ((irc->status & USTATUS_IDENTIFIED) && iu != irc->user) {
			irc_setpass(irc, NULL);
			irc->status &= ~USTATUS_IDENTIFIED;
			irc_umode_set(irc, "-R", 1);

			if (irc->caps & CAP_SASL) {
				irc_send_num(irc, 901, "%s!%s@%s :You are now logged out",
					irc->user->nick, irc->user->user, irc->user->host);
			}

			irc_rootmsg(irc, "Changing nicks resets your identify status. "
			            "Re-identify or register a new account if you want "
			            "your configuration to be saved. See \x02help "
			            "nick_changes\x02.");
		}

		if (strcmp(cmd[1], irc->user->nick) != 0) {
			irc_user_set_nick(irc->user, cmd[1]);
		}
	} else {
		g_free(irc->user->nick);
		irc->user->nick = g_strdup(cmd[1]);

		irc_check_login(irc);
	}
}

static void irc_cmd_quit(irc_t *irc, char **cmd)
{
	if (cmd[1] && *cmd[1]) {
		irc_abort(irc, 0, "Quit: %s", cmd[1]);
	} else {
		irc_abort(irc, 0, "Leaving...");
	}
}

static void irc_cmd_ping(irc_t *irc, char **cmd)
{
	irc_write(irc, ":%s PONG %s :%s", irc->root->host,
	          irc->root->host, cmd[1] ? cmd[1] : irc->root->host);
}

static void irc_cmd_pong(irc_t *irc, char **cmd)
{
	/* We could check the value we get back from the user, but in
	   fact we don't care, we're just happy s/he's still alive. */
	irc->last_pong = gettime();
	irc->pinging = 0;
}

static void irc_cmd_join(irc_t *irc, char **cmd)
{
	char *comma, *s = cmd[1];

	while (s) {
		irc_channel_t *ic;

		if ((comma = strchr(s, ','))) {
			*comma = '\0';
		}

		if ((ic = irc_channel_by_name(irc, s)) == NULL &&
		    (ic = irc_channel_new(irc, s))) {
			if (strcmp(set_getstr(&ic->set, "type"), "control") != 0) {
				/* Autoconfiguration is for control channels only ATM. */
			} else if (bee_group_by_name(ic->irc->b, ic->name + 1, FALSE)) {
				set_setstr(&ic->set, "group", ic->name + 1);
				set_setstr(&ic->set, "fill_by", "group");
			} else if (set_setstr(&ic->set, "protocol", ic->name + 1)) {
				set_setstr(&ic->set, "fill_by", "protocol");
			} else if (set_setstr(&ic->set, "account", ic->name + 1)) {
				set_setstr(&ic->set, "fill_by", "account");
			} else {
				/* The set commands above will run this already,
				   but if we didn't hit any, we have to fill the
				   channel with the default population. */
				bee_irc_channel_update(ic->irc, ic, NULL);
			}
		} else if (ic == NULL) {
			irc_send_num(irc, 479, "%s :Invalid channel name", s);
			goto next;
		}

		if (ic->flags & IRC_CHANNEL_JOINED) {
			/* Dude, you're already there...
			   RFC doesn't have any reply for that though? */
			goto next;
		}

		if (ic->f->join && !ic->f->join(ic)) {
			/* The story is: FALSE either means the handler
			   showed an error message, or is doing some work
			   before the join should be confirmed. (In the
			   latter case, the caller should take care of that
			   confirmation.) TRUE means all's good, let the
			   user join the channel right away. */
			goto next;
		}

		irc_channel_add_user(ic, irc->user);

next:
		if (comma) {
			s = comma + 1;
			*comma = ',';
		} else {
			break;
		}
	}
}

static void irc_cmd_names(irc_t *irc, char **cmd)
{
	irc_channel_t *ic;

	if (cmd[1] && (ic = irc_channel_by_name(irc, cmd[1]))) {
		irc_send_names(ic);
	}
	/* With no args, we should show /names of all chans. Make the code
	   below work well if necessary.
	else
	{
	        GSList *l;

	        for( l = irc->channels; l; l = l->next )
	                irc_send_names( l->data );
	}
	*/
}

static void irc_cmd_part(irc_t *irc, char **cmd)
{
	irc_channel_t *ic;

	if ((ic = irc_channel_by_name(irc, cmd[1])) == NULL) {
		irc_send_num(irc, 403, "%s :No such channel", cmd[1]);
	} else if (irc_channel_del_user(ic, irc->user, IRC_CDU_PART, cmd[2])) {
		if (ic->f->part) {
			ic->f->part(ic, NULL);
		}
	} else {
		irc_send_num(irc, 442, "%s :You're not on that channel", cmd[1]);
	}
}

static void irc_cmd_whois(irc_t *irc, char **cmd)
{
	char *nick = cmd[1];
	irc_user_t *iu = irc_user_by_name(irc, nick);

	if (iu) {
		irc_send_whois(iu);
	} else {
		irc_send_num(irc, 401, "%s :Nick does not exist", nick);
	}
}

static void irc_cmd_whowas(irc_t *irc, char **cmd)
{
	/* For some reason irssi tries a whowas when whois fails. We can
	   ignore this, but then the user never gets a "user not found"
	   message from irssi which is a bit annoying. So just respond
	   with not-found and irssi users will get better error messages */

	irc_send_num(irc, 406, "%s :Nick does not exist", cmd[1]);
	irc_send_num(irc, 369, "%s :End of WHOWAS", cmd[1]);
}

static void irc_cmd_motd(irc_t *irc, char **cmd)
{
	irc_send_motd(irc);
}

static void irc_cmd_mode(irc_t *irc, char **cmd)
{
	if (irc_channel_name_ok(cmd[1])) {
		irc_channel_t *ic;

		if ((ic = irc_channel_by_name(irc, cmd[1])) == NULL) {
			irc_send_num(irc, 403, "%s :No such channel", cmd[1]);
		} else if (cmd[2]) {
			if (*cmd[2] == '+' || *cmd[2] == '-') {
				irc_send_num(irc, 477, "%s :Can't change channel modes", cmd[1]);
			} else if (*cmd[2] == 'b') {
				irc_send_num(irc, 368, "%s :No bans possible", cmd[1]);
			}
		} else {
			irc_send_num(irc, 324, "%s +%s", cmd[1], ic->mode);
		}
	} else {
		if (nick_cmp(NULL, cmd[1], irc->user->nick) == 0) {
			if (cmd[2]) {
				irc_umode_set(irc, cmd[2], 0);
			} else {
				irc_send_num(irc, 221, "+%s", irc->umode);
			}
		} else {
			irc_send_num(irc, 502, ":Don't touch their modes");
		}
	}
}

static void irc_cmd_who(irc_t *irc, char **cmd)
{
	char *channel = cmd[1];
	irc_channel_t *ic;
	irc_user_t *iu;

	if (!channel || *channel == '0' || *channel == '*' || !*channel) {
		GList *all_users = g_hash_table_get_values(irc->nick_user_hash);
		irc_send_who(irc, (GSList *) all_users, "**");
		g_list_free(all_users);
	} else if ((ic = irc_channel_by_name(irc, channel))) {
		irc_send_who(irc, ic->users, channel);
	} else if ((iu = irc_user_by_name(irc, channel))) {
		/* Tiny hack! */
		GSList *l = g_slist_append(NULL, iu);
		irc_send_who(irc, l, channel);
		g_slist_free(l);
	} else {
		irc_send_num(irc, 403, "%s :No such channel", channel);
	}
}

static void irc_cmd_privmsg(irc_t *irc, char **cmd)
{
	irc_channel_t *ic;
	irc_user_t *iu;

	if (!cmd[2]) {
		irc_send_num(irc, 412, ":No text to send");
		return;
	}

	/* Don't treat CTCP actions as real CTCPs, just convert them right now. */
	if (g_strncasecmp(cmd[2], "\001ACTION", 7) == 0) {
		cmd[2] += 4;
		memcpy(cmd[2], "/me", 3);
		if (cmd[2][strlen(cmd[2]) - 1] == '\001') {
			cmd[2][strlen(cmd[2]) - 1] = '\0';
		}
	}

	if (irc_channel_name_ok(cmd[1]) &&
	    (ic = irc_channel_by_name(irc, cmd[1]))) {
		if (cmd[2][0] == '\001') {
			/* CTCPs to channels? Nah. Maybe later. */
		} else if (ic->f->privmsg) {
			ic->f->privmsg(ic, cmd[2]);
		}
	} else if ((iu = irc_user_by_name(irc, cmd[1]))) {
		if (cmd[2][0] == '\001') {
			char **ctcp;

			if (iu->f->ctcp == NULL) {
				return;
			}
			if (cmd[2][strlen(cmd[2]) - 1] == '\001') {
				cmd[2][strlen(cmd[2]) - 1] = '\0';
			}

			ctcp = split_command_parts(cmd[2] + 1, 0);
			iu->f->ctcp(iu, ctcp);
		} else if (iu->f->privmsg) {
			iu->last_channel = NULL;
			iu->f->privmsg(iu, cmd[2]);
		}
	} else {
		irc_send_num(irc, 401, "%s :No such nick/channel", cmd[1]);
	}
}

static void irc_cmd_notice(irc_t *irc, char **cmd)
{
	irc_user_t *iu;

	if (!cmd[2]) {
		irc_send_num(irc, 412, ":No text to send");
		return;
	}

	/* At least for now just echo. IIRC some IRC clients use self-notices
	   for lag checks, so try to support that. */
	if (nick_cmp(NULL, cmd[1], irc->user->nick) == 0) {
		irc_send_msg(irc->user, "NOTICE", irc->user->nick, cmd[2], NULL);
	} else if ((iu = irc_user_by_name(irc, cmd[1]))) {
		iu->f->privmsg(iu, cmd[2]);
	}
}

static void irc_cmd_nickserv(irc_t *irc, char **cmd)
{
	/* [SH] This aliases the NickServ command to PRIVMSG root */
	/* [TV] This aliases the NS command to PRIVMSG root as well */
	root_command(irc, cmd + 1);
}

static void irc_cmd_oper_hack(irc_t *irc, char **cmd);

static void irc_cmd_oper(irc_t *irc, char **cmd)
{
	/* Very non-standard evil but useful/secure hack, see below. */
	if (irc->status & OPER_HACK_ANY) {
		return irc_cmd_oper_hack(irc, cmd);
	}

	if (global.conf->oper_pass &&
	    (strncmp(global.conf->oper_pass, "md5:", 4) == 0 ?
	     md5_verify_password(cmd[2], global.conf->oper_pass + 4) == 0 :
	     strcmp(cmd[2], global.conf->oper_pass) == 0)) {
		irc_umode_set(irc, "+o", 1);
		irc_send_num(irc, 381, ":Password accepted");
	} else {
		irc_send_num(irc, 491, ":Incorrect password");
	}
}

static void irc_cmd_oper_hack(irc_t *irc, char **cmd)
{
	char *password = g_strjoinv(" ", cmd + 2);

	/* /OPER can now also be used to enter IM/identify passwords without
	   echoing. It's a hack but the extra password security is worth it. */
	if (irc->status & OPER_HACK_ACCOUNT_PASSWORD) {
		account_t *a;

		for (a = irc->b->accounts; a; a = a->next) {
			if (strcmp(a->pass, PASSWORD_PENDING) == 0) {
				set_setstr(&a->set, "password", password);
				irc_rootmsg(irc, "Password added to IM account "
				            "%s", a->tag);
				/* The IRC client may expect this. 491 suggests the OPER
				   password was wrong, so the client won't expect a +o.
				   It may however repeat the password prompt. We'll see. */
				irc_send_num(irc, 491, ":Password added to IM account "
				             "%s", a->tag);
			}
		}
	} else if (irc->status & OPER_HACK_IDENTIFY) {
		char *send_cmd[] = { "identify", password, NULL, NULL };
		irc->status &= ~OPER_HACK_IDENTIFY;
		if (irc->status & OPER_HACK_IDENTIFY_NOLOAD) {
			send_cmd[1] = "-noload";
			send_cmd[2] = password;
		} else if (irc->status & OPER_HACK_IDENTIFY_FORCE) {
			send_cmd[1] = "-force";
			send_cmd[2] = password;
		}
		irc_send_num(irc, 491, ":Trying to identify");
		root_command(irc, send_cmd);
	} else if (irc->status & OPER_HACK_REGISTER) {
		char *send_cmd[] = { "register", password, NULL };
		irc_send_num(irc, 491, ":Trying to identify");
		root_command(irc, send_cmd);
	}

	irc->status &= ~OPER_HACK_ANY;
	g_free(password);
}

static void irc_cmd_invite(irc_t *irc, char **cmd)
{
	irc_channel_t *ic;
	irc_user_t *iu;

	if ((iu = irc_user_by_name(irc, cmd[1])) == NULL) {
		irc_send_num(irc, 401, "%s :No such nick", cmd[1]);
		return;
	} else if ((ic = irc_channel_by_name(irc, cmd[2])) == NULL) {
		irc_send_num(irc, 403, "%s :No such channel", cmd[2]);
		return;
	}

	if (!ic->f->invite) {
		irc_send_num(irc, 482, "%s :Can't invite people here", cmd[2]);
	} else if (ic->f->invite(ic, iu)) {
		irc_send_num(irc, 341, "%s %s", iu->nick, ic->name);
	}
}

static void irc_cmd_kick(irc_t *irc, char **cmd)
{
	irc_channel_t *ic;
	irc_user_t *iu;

	if ((iu = irc_user_by_name(irc, cmd[2])) == NULL) {
		irc_send_num(irc, 401, "%s :No such nick", cmd[2]);
		return;
	} else if ((ic = irc_channel_by_name(irc, cmd[1])) == NULL) {
		irc_send_num(irc, 403, "%s :No such channel", cmd[1]);
		return;
	} else if (!ic->f->kick) {
		irc_send_num(irc, 482, "%s :Can't kick people here", cmd[1]);
		return;
	}

	ic->f->kick(ic, iu, cmd[3] ? cmd[3] : NULL);
}

static void irc_cmd_userhost(irc_t *irc, char **cmd)
{
	int i;

	/* [TV] Usable USERHOST-implementation according to
	        RFC1459. Without this, mIRC shows an error
	        while connecting, and the used way of rejecting
	        breaks standards.
	*/

	for (i = 1; cmd[i]; i++) {
		irc_user_t *iu = irc_user_by_name(irc, cmd[i]);

		if (iu) {
			irc_send_num(irc, 302, ":%s=%c%s@%s", iu->nick,
			             irc_user_get_away(iu) ? '-' : '+',
			             iu->user, iu->host);
		}
	}
}

static void irc_cmd_ison(irc_t *irc, char **cmd)
{
	char buff[IRC_MAX_LINE];
	int lenleft, i;

	buff[0] = '\0';

	/* [SH] Leave room for : and \0 */
	lenleft = IRC_MAX_LINE - 2;

	for (i = 1; cmd[i]; i++) {
		char *this, *next;

		this = cmd[i];
		while (*this) {
			irc_user_t *iu;

			if ((next = strchr(this, ' '))) {
				*next = 0;
			}

			if ((iu = irc_user_by_name(irc, this)) &&
			    iu->bu && iu->bu->flags & BEE_USER_ONLINE) {
				lenleft -= strlen(iu->nick) + 1;

				if (lenleft < 0) {
					break;
				}

				strcat(buff, iu->nick);
				strcat(buff, " ");
			}

			if (next) {
				*next = ' ';
				this = next + 1;
			} else {
				break;
			}
		}

		/* *sigh* */
		if (lenleft < 0) {
			break;
		}
	}

	if (strlen(buff) > 0) {
		buff[strlen(buff) - 1] = '\0';
	}

	irc_send_num(irc, 303, ":%s", buff);
}

static void irc_cmd_watch(irc_t *irc, char **cmd)
{
	int i;

	/* Obviously we could also mark a user structure as being
	   watched, but what if the WATCH command is sent right
	   after connecting? The user won't exist yet then... */
	for (i = 1; cmd[i]; i++) {
		char *nick;
		irc_user_t *iu;

		if (!cmd[i][0] || !cmd[i][1]) {
			break;
		}

		nick = g_strdup(cmd[i] + 1);
		nick_lc(irc, nick);

		iu = irc_user_by_name(irc, nick);

		if (cmd[i][0] == '+') {
			if (!g_hash_table_lookup(irc->watches, nick)) {
				g_hash_table_insert(irc->watches, nick, nick);
			}

			if (iu && iu->bu && iu->bu->flags & BEE_USER_ONLINE) {
				irc_send_num(irc, 604, "%s %s %s %d :%s", iu->nick, iu->user,
				             iu->host, (int) time(NULL), "is online");
			} else {
				irc_send_num(irc, 605, "%s %s %s %d :%s", nick, "*", "*",
				             (int) time(NULL), "is offline");
			}
		} else if (cmd[i][0] == '-') {
			gpointer okey, ovalue;

			if (g_hash_table_lookup_extended(irc->watches, nick, &okey, &ovalue)) {
				g_hash_table_remove(irc->watches, okey);
				g_free(okey);

				irc_send_num(irc, 602, "%s %s %s %d :%s", nick, "*", "*", 0, "Stopped watching");
			}
		}
	}
}

static void irc_cmd_topic(irc_t *irc, char **cmd)
{
	irc_channel_t *ic = irc_channel_by_name(irc, cmd[1]);
	const char *new = cmd[2];

	if (ic == NULL) {
		irc_send_num(irc, 403, "%s :No such channel", cmd[1]);
	} else if (new) {
		if (ic->f->topic == NULL) {
			irc_send_num(irc, 482, "%s :Can't change this channel's topic", ic->name);
		} else if (ic->f->topic(ic, new)) {
			irc_send_topic(ic, TRUE);
		}
	} else {
		irc_send_topic(ic, FALSE);
	}
}

static void irc_cmd_away(irc_t *irc, char **cmd)
{
	if (cmd[1] && *cmd[1]) {
		char away[strlen(cmd[1]) + 1];
		int i, j;

		/* Copy away string, but skip control chars. Mainly because
		   Jabber really doesn't like them. */
		for (i = j = 0; cmd[1][i]; i++) {
			if ((unsigned char) (away[j] = cmd[1][i]) >= ' ') {
				j++;
			}
		}
		away[j] = '\0';

		irc_send_num(irc, 306, ":You're now away: %s", away);
		set_setstr(&irc->b->set, "away", away);
	} else {
		irc_send_num(irc, 305, ":Welcome back");
		set_setstr(&irc->b->set, "away", NULL);
	}
}

static void irc_cmd_list(irc_t *irc, char **cmd)
{
	GSList *l;

	for (l = irc->channels; l; l = l->next) {
		irc_channel_t *ic = l->data;

		irc_send_num(irc, 322, "%s %d :%s",
		             ic->name, g_slist_length(ic->users), ic->topic ? : "");
	}
	irc_send_num(irc, 323, ":%s", "End of /LIST");
}

static void irc_cmd_version(irc_t *irc, char **cmd)
{
	irc_send_num(irc, 351, "%s-%s. %s :",
	             PACKAGE, BITLBEE_VERSION, irc->root->host);
}

static void irc_cmd_completions(irc_t *irc, char **cmd)
{
	help_t *h;
	set_t *s;
	int i;

	irc_send_msg_raw(irc->root, "NOTICE", irc->user->nick, "COMPLETIONS OK");

	for (i = 0; root_commands[i].command; i++) {
		irc_send_msg_f(irc->root, "NOTICE", irc->user->nick, "COMPLETIONS %s", root_commands[i].command);
	}

	for (h = global.help; h; h = h->next) {
		irc_send_msg_f(irc->root, "NOTICE", irc->user->nick, "COMPLETIONS help %s", h->title);
	}

	for (s = irc->b->set; s; s = s->next) {
		irc_send_msg_f(irc->root, "NOTICE", irc->user->nick, "COMPLETIONS set %s", s->key);
	}

	irc_send_msg_raw(irc->root, "NOTICE", irc->user->nick, "COMPLETIONS END");
}

static void irc_cmd_rehash(irc_t *irc, char **cmd)
{
	if (global.conf->runmode == RUNMODE_INETD) {
		ipc_master_cmd_rehash(NULL, NULL);
	} else {
		ipc_to_master(cmd);
	}

	irc_send_num(irc, 382, "%s :Rehashing", global.conf_file);
}

static const command_t irc_commands[] = {
	{ "cap",         1, irc_cmd_cap,         0 },
	{ "pass",        1, irc_cmd_pass,        0 },
	{ "proxy",       5, irc_cmd_proxy,       IRC_CMD_PRE_LOGIN },
	{ "user",        4, irc_cmd_user,        IRC_CMD_PRE_LOGIN },
	{ "nick",        1, irc_cmd_nick,        0 },
	{ "quit",        0, irc_cmd_quit,        0 },
	{ "ping",        0, irc_cmd_ping,        0 },
	{ "pong",        0, irc_cmd_pong,        IRC_CMD_LOGGED_IN },
	{ "join",        1, irc_cmd_join,        IRC_CMD_LOGGED_IN },
	{ "names",       1, irc_cmd_names,       IRC_CMD_LOGGED_IN },
	{ "part",        1, irc_cmd_part,        IRC_CMD_LOGGED_IN },
	{ "whois",       1, irc_cmd_whois,       IRC_CMD_LOGGED_IN },
	{ "whowas",      1, irc_cmd_whowas,      IRC_CMD_LOGGED_IN },
	{ "motd",        0, irc_cmd_motd,        IRC_CMD_LOGGED_IN },
	{ "mode",        1, irc_cmd_mode,        IRC_CMD_LOGGED_IN },
	{ "who",         0, irc_cmd_who,         IRC_CMD_LOGGED_IN },
	{ "privmsg",     1, irc_cmd_privmsg,     IRC_CMD_LOGGED_IN },
	{ "notice",      1, irc_cmd_notice,      IRC_CMD_LOGGED_IN },
	{ "nickserv",    1, irc_cmd_nickserv,    IRC_CMD_LOGGED_IN },
	{ "ns",          1, irc_cmd_nickserv,    IRC_CMD_LOGGED_IN },
	{ "away",        0, irc_cmd_away,        IRC_CMD_LOGGED_IN },
	{ "version",     0, irc_cmd_version,     IRC_CMD_LOGGED_IN },
	{ "completions", 0, irc_cmd_completions, IRC_CMD_LOGGED_IN },
	{ "userhost",    1, irc_cmd_userhost,    IRC_CMD_LOGGED_IN },
	{ "ison",        1, irc_cmd_ison,        IRC_CMD_LOGGED_IN },
	{ "watch",       1, irc_cmd_watch,       IRC_CMD_LOGGED_IN },
	{ "invite",      2, irc_cmd_invite,      IRC_CMD_LOGGED_IN },
	{ "kick",        2, irc_cmd_kick,        IRC_CMD_LOGGED_IN },
	{ "topic",       1, irc_cmd_topic,       IRC_CMD_LOGGED_IN },
	{ "oper",        2, irc_cmd_oper,        IRC_CMD_LOGGED_IN },
	{ "list",        0, irc_cmd_list,        IRC_CMD_LOGGED_IN },
	{ "die",         0, NULL,                IRC_CMD_OPER_ONLY | IRC_CMD_TO_MASTER },
	{ "deaf",        0, NULL,                IRC_CMD_OPER_ONLY | IRC_CMD_TO_MASTER },
	{ "wallops",     1, NULL,                IRC_CMD_OPER_ONLY | IRC_CMD_TO_MASTER },
	{ "wall",        1, NULL,                IRC_CMD_OPER_ONLY | IRC_CMD_TO_MASTER },
	{ "rehash",      0, irc_cmd_rehash,      IRC_CMD_OPER_ONLY },
	{ "restart",     0, NULL,                IRC_CMD_OPER_ONLY | IRC_CMD_TO_MASTER },
	{ "kill",        2, NULL,                IRC_CMD_OPER_ONLY | IRC_CMD_TO_MASTER },
	{ "authenticate", 1, irc_cmd_authenticate, 0 },
	{ NULL }
};

void irc_exec(irc_t *irc, char *cmd[])
{
	int i, n_arg;

	if (!cmd[0]) {
		return;
	}

	for (i = 0; irc_commands[i].command; i++) {
		if (g_strcasecmp(irc_commands[i].command, cmd[0]) == 0) {
			/* There should be no typo in the next line: */
			for (n_arg = 0; cmd[n_arg]; n_arg++) {
				;
			}
			n_arg--;

			if (irc_commands[i].flags & IRC_CMD_PRE_LOGIN && irc->status & USTATUS_LOGGED_IN) {
				irc_send_num(irc, 462, ":Only allowed before logging in");
			} else if (irc_commands[i].flags & IRC_CMD_LOGGED_IN && !(irc->status & USTATUS_LOGGED_IN)) {
				irc_send_num(irc, 451, ":Register first");
			} else if (irc_commands[i].flags & IRC_CMD_OPER_ONLY && !strchr(irc->umode, 'o')) {
				irc_send_num(irc, 481, ":Permission denied - You're not an IRC operator");
			} else if (n_arg < irc_commands[i].required_parameters) {
				irc_send_num(irc, 461, "%s :Need more parameters", cmd[0]);
			} else if (irc_commands[i].flags & IRC_CMD_TO_MASTER) {
				/* IPC doesn't make sense in inetd mode,
				    but the function will catch that. */
				ipc_to_master(cmd);
			} else {
				irc_commands[i].execute(irc, cmd);
			}

			return;
		}
	}

	if (irc->status & USTATUS_LOGGED_IN) {
		irc_send_num(irc, 421, "%s :Unknown command", cmd[0]);
	}
}