Exemple #1
0
bool ChannelManager::UpdateUser(int channel_id_, const IM::User& user_)
{

    auto it = m_mapChannels.find(channel_id_);
    if (it != m_mapChannels.end())
    {
        int64_t user_id = user_.id();
        auto user_it = find_if (it->second.m_users.begin(), it->second.m_users.end(),
        [&] (IM::User& v_user_)
        {
            return v_user_.id() == user_id;
        });


        if (user_it != it->second.m_users.end())
        {
            user_it->set_id(user_.id());
            user_it->set_name(user_.name());
            user_it->set_nick_name(user_.nick_name());
            user_it->set_sex(user_.sex());

            return true;
        }
        else
        {
            // not find user id
            return false;
        }
    }
    else
    {
        // not find ch_id
        return false;
    }

}
/*
 * ms_nick - server message handler for nicks
 * parv[0] = sender prefix
 * parv[1] = nickname
 *
 * If from server, source is client:
 *   parv[2] = timestamp
 *
 * Source is server:
 *   parv[2] = hopcount
 *   parv[3] = timestamp
 *   parv[4] = username
 *   parv[5] = hostname
 *   parv[6] = umode (optional)
 *   parv[parc-3] = IP#                 <- Only Protocol >= 10
 *   parv[parc-2] = YXX, numeric nick   <- Only Protocol >= 10
 *   parv[parc-1] = info
 *   parv[0] = server
 */
int ms_nick(struct Client* cptr, struct Client* sptr, int parc, char* parv[])
{
  struct Client *acptr;
  char nick[NICKLEN + 2];
  time_t lastnick = 0;
  int differ = 1;
  const char *type;

  assert(0 != cptr);
  assert(0 != sptr);
  assert(IsServer(cptr));

  if ((IsServer(sptr) && parc < 8) || parc < 3)
  {
    sendto_opmask_butone(0, SNO_OLDSNO, "bad NICK param count for %s from %C",
			 parv[1], cptr);
    return need_more_params(sptr, "NICK");
  }

  ircd_strncpy(nick, parv[1], NICKLEN);
  nick[NICKLEN] = '\0';

  if (IsServer(sptr))
  {
    lastnick = atoi(parv[3]);
    if (lastnick > OLDEST_TS && !IsBurstOrBurstAck(sptr)) 
      cli_serv(sptr)->lag = TStime() - lastnick;
  }
  else
  {
    lastnick = atoi(parv[2]); 
    if (lastnick > OLDEST_TS && !IsBurstOrBurstAck(sptr))
      cli_serv(cli_user(sptr)->server)->lag = TStime() - lastnick;
  }
  /*
   * If do_nick_name() returns a null name OR if the server sent a nick
   * name and do_nick_name() changed it in some way (due to rules of nick
   * creation) then reject it. If from a server and we reject it,
   * and KILL it. -avalon 4/4/92
   */
  if (!do_nick_name(nick) || strcmp(nick, parv[1]))
  {
    send_reply(sptr, ERR_ERRONEUSNICKNAME, parv[1]);
    
    ++ServerStats->is_kill;
    sendto_opmask_butone(0, SNO_OLDSNO, "Bad Nick: %s From: %s %C", parv[1],
			 parv[0], cptr);
    sendcmdto_one(&me, CMD_KILL, cptr, "%s :%s (%s <- %s[%s])",
		  IsServer(sptr) ? parv[parc - 2] : parv[0], cli_name(&me), parv[1],
		  nick, cli_name(cptr));
    if (!IsServer(sptr))
    {
      /*
       * bad nick _change_
       */
      sendcmdto_serv_butone(&me, CMD_KILL, 0, "%s :%s (%s <- %s!%s@%s)",
			    parv[0], cli_name(&me), cli_name(cptr), parv[0],
			    cli_user(sptr) ? cli_username(sptr) : "",
			    cli_user(sptr) ? cli_name(cli_user(sptr)->server) :
			    cli_name(cptr));
    }
    return 0;
  }
  /* Check against nick name collisions. */
  if ((acptr = FindClient(nick)) == NULL)
    /* No collisions, all clear... */
    return set_nick_name(cptr, sptr, nick, parc, parv);

  /*
   * If acptr == sptr, then we have a client doing a nick
   * change between *equivalent* nicknames as far as server
   * is concerned (user is changing the case of his/her
   * nickname or somesuch)
   */
  if (acptr == sptr)
  {
    if (strcmp(cli_name(acptr), nick) != 0)
      /* Allows change of case in his/her nick */
      return set_nick_name(cptr, sptr, nick, parc, parv);
    else
      /* Setting their nick to what it already is? Ignore it. */
      return 0;
  }
  /* now we know we have a real collision. */
  /*
   * Note: From this point forward it can be assumed that
   * acptr != sptr (point to different client structures).
   */
  assert(acptr != sptr);
  /*
   * If the older one is "non-person", the new entry is just
   * allowed to overwrite it. Just silently drop non-person,
   * and proceed with the nick. This should take care of the
   * "dormant nick" way of generating collisions...
   */
  if (IsUnknown(acptr) && MyConnect(acptr))
  {
    ServerStats->is_ref++;
    IPcheck_connect_fail(acptr);
    exit_client(cptr, acptr, &me, "Overridden by other sign on");
    return set_nick_name(cptr, sptr, nick, parc, parv);
  }
  /*
   * Decide, we really have a nick collision and deal with it
   */
  /*
   * NICK was coming from a server connection.
   * This means we have a race condition (two users signing on
   * at the same time), or two net fragments reconnecting with the same nick.
   * The latter can happen because two different users connected
   * or because one and the same user switched server during a net break.
   * If the TimeStamps are equal, we kill both (or only 'new'
   * if it was a ":server NICK new ...").
   * Otherwise we kill the youngest when user@host differ,
   * or the oldest when they are the same.
   * We treat user and ~user as different, because if it wasn't
   * a faked ~user the AUTH wouldn't have added the '~'.
   * --Run
   *
   */
  if (IsServer(sptr))
  {
    struct irc_in_addr ip;
    /*
     * A new NICK being introduced by a neighbouring
     * server (e.g. message type ":server NICK new ..." received)
     *
     * compare IP address and username
     */
    base64toip(parv[parc - 3], &ip);
    differ =  (0 != memcmp(&cli_ip(acptr), &ip, sizeof(cli_ip(acptr)))) ||
              (0 != ircd_strcmp(cli_user(acptr)->username, parv[4]));
    sendto_opmask_butone(0, SNO_OLDSNO, "Nick collision on %C (%C %Tu <- "
			 "%C %Tu (%s user@host))", acptr, cli_from(acptr),
			 cli_lastnick(acptr), cptr, lastnick,
			 differ ? "Different" : "Same");
  }
  else
  {
    /*
     * A NICK change has collided (e.g. message type ":old NICK new").
     *
     * compare IP address and username
     */
    differ =  (0 != memcmp(&cli_ip(acptr), &cli_ip(sptr), sizeof(cli_ip(acptr)))) ||
              (0 != ircd_strcmp(cli_user(acptr)->username, cli_user(sptr)->username));
    sendto_opmask_butone(0, SNO_OLDSNO, "Nick change collision from %C to "
			 "%C (%C %Tu <- %C %Tu)", sptr, acptr, cli_from(acptr),
			 cli_lastnick(acptr), cptr, lastnick);
  }
  type = differ ? "overruled by older nick" : "nick collision from same user@host";
  /*
   * Now remove (kill) the nick on our side if it is the youngest.
   * If no timestamp was received, we ignore the incoming nick
   * (and expect a KILL for our legit nick soon ):
   * When the timestamps are equal we kill both nicks. --Run
   * acptr->from != cptr should *always* be true (?).
   *
   * This exits the client sending the NICK message
   */
  if ((differ && lastnick >= cli_lastnick(acptr)) ||
      (!differ && lastnick <= cli_lastnick(acptr)))
  {
    ServerStats->is_kill++;
    if (!IsServer(sptr))
    {
      /* If this was a nick change and not a nick introduction, we
       * need to ensure that we remove our record of the client, and
       * send a KILL to the whole network.
       */
      assert(!MyConnect(sptr));
      /* Inform the rest of the net... */
      sendcmdto_serv_butone(&me, CMD_KILL, 0, "%C :%s (%s)",
                            sptr, cli_name(&me), type);
      /* Don't go sending off a QUIT message... */
      SetFlag(sptr, FLAG_KILLED);
      /* Remove them locally. */
      exit_client_msg(cptr, sptr, &me,
                      "Killed (%s (%s))",
                      feature_str(FEAT_HIS_SERVERNAME), type);
    }
    else
    {
      /* If the origin is a server, this was a new client, so we only
       * send the KILL in the direction it came from.  We have no
       * client record that we would have to clean up.
       */
      sendcmdto_one(&me, CMD_KILL, cptr, "%s :%s (%s)",
                    parv[parc - 2], cli_name(&me), type);
    }
    /* If the timestamps differ and we just killed sptr, we don't need to kill
     * acptr as well.
     */
    if (lastnick != cli_lastnick(acptr))
      return 0;
  }
  /* Tell acptr why we are killing it. */
  send_reply(acptr, ERR_NICKCOLLISION, nick);

  ServerStats->is_kill++;
  SetFlag(acptr, FLAG_KILLED);
  /*
   * This exits the client we had before getting the NICK message
   */
  sendcmdto_serv_butone(&me, CMD_KILL, NULL, "%C :%s (%s)",
                        acptr, feature_str(FEAT_HIS_SERVERNAME),
                        type);
  exit_client_msg(cptr, acptr, &me, "Killed (%s (%s))",
                  feature_str(FEAT_HIS_SERVERNAME), type);
  if (lastnick == cli_lastnick(acptr))
    return 0;
  if (sptr == NULL)
    return 0;
  return set_nick_name(cptr, sptr, nick, parc, parv);
}
/*
 * m_nick - message handler for local clients
 * parv[0] = sender prefix
 * parv[1] = nickname
 */
int m_nick(struct Client* cptr, struct Client* sptr, int parc, char* parv[])
{
  struct Client* acptr;
  char           nick[NICKLEN + 2];
  char*          arg;
  char*          s;
  const char*    client_name;

  assert(0 != cptr);
  assert(cptr == sptr);

  if (IsServerPort(cptr))
    return exit_client(cptr, cptr, &me, "Use a different port");

  /*
   * parv[0] will be empty for clients connecting for the first time
   */
  client_name = (*(cli_name(sptr))) ? cli_name(sptr) : "*";

  if (parc < 2) {
    send_reply(sptr, ERR_NONICKNAMEGIVEN);
    return 0;
  }

  /*
   * Don't let them send make us send back a really long string of
   * garbage
   */
  arg = parv[1];
  if (strlen(arg) > IRCD_MIN(NICKLEN, feature_int(FEAT_NICKLEN)))
    arg[IRCD_MIN(NICKLEN, feature_int(FEAT_NICKLEN))] = '\0';

  if ((s = strchr(arg, '~')))
    *s = '\0';

  strcpy(nick, arg);

  /*
   * If do_nick_name() returns a null name then reject it.
   */
  if (0 == do_nick_name(nick)) {
    send_reply(sptr, ERR_ERRONEUSNICKNAME, arg);
    return 0;
  }

  /* 
   * Check if this is a LOCAL user trying to use a reserved (Juped)
   * nick, if so tell him that it's a nick in use...
   */
  if (isNickJuped(nick)) {
    send_reply(sptr, ERR_NICKNAMEINUSE, nick);
    return 0;                        /* NICK message ignored */
  }

  if (!(acptr = FindClient(nick))) {
    /*
     * No collisions, all clear...
     */
    return set_nick_name(cptr, sptr, nick, parc, parv);
  }
  if (IsServer(acptr)) {
    send_reply(sptr, ERR_NICKNAMEINUSE, nick);
    return 0;                        /* NICK message ignored */
  }
  /*
   * If acptr == sptr, then we have a client doing a nick
   * change between *equivalent* nicknames as far as server
   * is concerned (user is changing the case of his/her
   * nickname or somesuch)
   */
  if (acptr == sptr) {
    /*
     * If acptr == sptr, then we have a client doing a nick
     * change between *equivalent* nicknames as far as server
     * is concerned (user is changing the case of his/her
     * nickname or somesuch)
     */
    if (0 != strcmp(cli_name(acptr), nick)) {
      /*
       * Allows change of case in his/her nick
       */
      return set_nick_name(cptr, sptr, nick, parc, parv);
    }
    /*
     * This is just ':old NICK old' type thing.
     * Just forget the whole thing here. There is
     * no point forwarding it to anywhere,
     * especially since servers prior to this
     * version would treat it as nick collision.
     */
    return 0;
  }
  /*
   * Note: From this point forward it can be assumed that
   * acptr != sptr (point to different client structures).
   */
  assert(acptr != sptr);
  /*
   * If the older one is "non-person", the new entry is just
   * allowed to overwrite it. Just silently drop non-person,
   * and proceed with the nick. This should take care of the
   * "dormant nick" way of generating collisions...
   *
   * XXX - hmmm can this happen after one is registered?
   *
   * Yes, client 1 connects to IRC and registers, client 2 connects and
   * sends "NICK foo" but doesn't send anything more.  client 1 now does
   * /nick foo, they should succeed and client 2 gets disconnected with
   * the message below.
   */
  if (IsUnknown(acptr) && MyConnect(acptr)) {
    ServerStats->is_ref++;
    IPcheck_connect_fail(acptr);
    exit_client(cptr, acptr, &me, "Overridden by other sign on");
    return set_nick_name(cptr, sptr, nick, parc, parv);
  }
  /*
   * NICK is coming from local client connection. Just
   * send error reply and ignore the command.
   */
  send_reply(sptr, ERR_NICKNAMEINUSE, nick);
  return 0;                        /* NICK message ignored */
}
/*
 * ms_nick - server message handler for nicks
 * parv[0] = sender prefix
 * parv[1] = nickname
 *
 * If from server, source is client:
 *   parv[2] = timestamp
 *
 * Source is server:
 *   parv[2] = hopcount
 *   parv[3] = timestamp
 *   parv[4] = username
 *   parv[5] = hostname
 *   parv[6] = umode (optional)
 *   parv[parc-3] = IP#                 <- Only Protocol >= 10
 *   parv[parc-2] = YXX, numeric nick   <- Only Protocol >= 10
 *   parv[parc-1] = info
 *   parv[0] = server
 */
int ms_nick(struct Client* cptr, struct Client* sptr, int parc, char* parv[])
{
  struct Client* acptr;
  char           nick[NICKLEN + 2];
  time_t         lastnick = 0;
  int            differ = 1;
  int            samelastnick = 0;
  
  assert(0 != cptr);
  assert(0 != sptr);
  assert(IsServer(cptr));

  if ((IsServer(sptr) && parc < 8) || parc < 3) {
    sendto_opmask_butone(0, SNO_OLDSNO, "bad NICK param count for %s from %C",
			 parv[1], cptr);
    return need_more_params(sptr, "NICK");
  }

  ircd_strncpy(nick, parv[1], NICKLEN);
  nick[NICKLEN] = '\0';

  if (IsServer(sptr)) {
    lastnick = atoi(parv[3]);
    if (lastnick > OLDEST_TS && !IsBurstOrBurstAck(sptr)) 
      cli_serv(sptr)->lag = TStime() - lastnick;
  }
  else {
    lastnick = atoi(parv[2]); 
    if (lastnick > OLDEST_TS && !IsBurstOrBurstAck(sptr))
      cli_serv(cli_user(sptr)->server)->lag = TStime() - lastnick;
  }
  /*
   * If do_nick_name() returns a null name OR if the server sent a nick
   * name and do_nick_name() changed it in some way (due to rules of nick
   * creation) then reject it. If from a server and we reject it,
   * and KILL it. -avalon 4/4/92
   */
  if (0 == do_nick_name(nick) || 0 != strcmp(nick, parv[1])) {
    send_reply(sptr, ERR_ERRONEUSNICKNAME, parv[1]);

    ++ServerStats->is_kill;
    sendto_opmask_butone(0, SNO_OLDSNO, "Bad Nick: %s From: %s %C", parv[1],
			 parv[0], cptr);
    sendcmdto_one(&me, CMD_KILL, cptr, "%s :%s (%s <- %s[%s])",
		  IsServer(sptr) ? parv[parc - 2] : parv[0], 
		  cli_name(&me), parv[1], nick, cli_name(cptr));
    if (!IsServer(sptr)) {
      /*
       * bad nick _change_
       */
      sendcmdto_serv_butone(&me, CMD_KILL, 0, "%s :%s (%s <- %s!%s@%s)",
			    parv[0], cli_name(&me), cli_name(cptr), parv[0],
			    cli_user(sptr) ? cli_username(sptr) : "",
			    cli_user(sptr) ? cli_name(cli_user(sptr)->server) :
			    cli_name(cptr));
    }
    return 0;
  }
  /*
   * Check against nick name collisions.
   *
   * Put this 'if' here so that the nesting goes nicely on the screen :)
   * We check against server name list before determining if the nickname
   * is present in the nicklist (due to the way the below for loop is
   * constructed). -avalon
   */
   
  assert(NULL == strchr(nick,'.'));

  acptr = FindClient(nick);
  if (!acptr) {
    /*
     * No collisions, all clear...
     */
    return set_nick_name(cptr, sptr, nick, parc, parv);
  }
  assert(0 != acptr);

  /*
   * If acptr == sptr, then we have a client doing a nick
   * change between *equivalent* nicknames as far as server
   * is concerned (user is changing the case of his/her
   * nickname or somesuch)
   */
  if (acptr == sptr) {
    if (strcmp(cli_name(acptr), nick) == 0)
      /*
       * This is just ':old NICK old' type thing.
       * Just forget the whole thing here. There is
       * no point forwarding it to anywhere,
       * especially since servers prior to this
       * version would treat it as nick collision.
       */
      return 0;                        /* NICK Message ignored */
    else
      /*
       * Allows change of case in his/her nick
       */
      return set_nick_name(cptr, sptr, nick, parc, parv);
  }

  /*
   * Note: From this point forward it can be assumed that
   * acptr != sptr (point to different client structures).
   */
  assert(acptr != sptr);
  /*
   * If the older one is "non-person", the new entry is just
   * allowed to overwrite it. Just silently drop non-person,
   * and proceed with the nick. This should take care of the
   * "dormant nick" way of generating collisions...
   */
  if (IsUnknown(acptr) && MyConnect(acptr)) {
    ++ServerStats->is_ref;
    IPcheck_connect_fail(cli_ip(acptr));
    exit_client(cptr, acptr, &me, "Overridden by other sign on");
    return set_nick_name(cptr, sptr, nick, parc, parv);
  }
  /*
   * Decide, we really have a nick collision and deal with it
   */
  /*
   * NICK was coming from a server connection.
   * This means we have a race condition (two users signing on
   * at the same time), or two net fragments reconnecting with the same nick.
   * The latter can happen because two different users connected
   * or because one and the same user switched server during a net break.
   * If the TimeStamps are equal, we kill both (or only 'new'
   * if it was a ":server NICK new ...").
   * Otherwise we kill the youngest when user@host differ,
   * or the oldest when they are the same.
   * We treat user and ~user as different, because if it wasn't
   * a faked ~user the AUTH wouldn't have added the '~'.
   * --Run
   *
   */


  if (IsServer(sptr)) {
    /*
     * A new NICK being introduced by a neighbouring
     * server (e.g. message type ":server NICK new ..." received)
     *
     * compare IP address and username
     */
    differ =  (cli_ip(acptr).s_addr != htonl(base64toint(parv[parc - 3]))) ||
              (0 != ircd_strcmp(cli_user(acptr)->username, parv[4]));
    sendto_opmask_butone(0, SNO_OLDSNO, "Nick collision on %C (%C %Tu <- "
			 "%C %Tu (%s user@host))", acptr, cli_from(acptr),
			 cli_lastnick(acptr), cptr, lastnick,
			 differ ? "Different" : "Same");
  }
  else {
    /*
     * A NICK change has collided (e.g. message type ":old NICK new").
     *
     * compare IP address and username
     */
    differ =  (cli_ip(acptr).s_addr != cli_ip(sptr).s_addr) ||
              (0 != ircd_strcmp(cli_user(acptr)->username, cli_user(sptr)->username));              
    sendto_opmask_butone(0, SNO_OLDSNO, "Nick change collision from %C to "
			 "%C (%C %Tu <- %C %Tu)", sptr, acptr, cli_from(acptr),
			 cli_lastnick(acptr), cptr, lastnick);
  }
  /*
   * Now remove (kill) the nick on our side if it is the youngest.
   * If no timestamp was received, we ignore the incoming nick
   * (and expect a KILL for our legit nick soon ):
   * When the timestamps are equal we kill both nicks. --Run
   * acptr->from != cptr should *always* be true (?).
   *
   * This exits the client sending the NICK message
   */
  if (cli_from(acptr) != cptr) {
    if ((differ && lastnick >= cli_lastnick(acptr)) ||
	(!differ && lastnick <= cli_lastnick(acptr))) {
      if (!IsServer(sptr)) {
        ++ServerStats->is_kill;
	sendcmdto_serv_butone(&me, CMD_KILL, NULL, "%C :%s (Nick collision)",
			      sptr, cli_name(&me));
        assert(!MyConnect(sptr));

        SetFlag(sptr, FLAG_KILLED);

	exit_client_msg(cptr, sptr, &me,
			       "Killed (%s (Nick collision))",
			       feature_str(FEAT_HIS_SERVERNAME));

	sptr = 0; /* Make sure we don't use the dead client */

      } else {
        /* We need to kill this incoming client, which hasn't been properly registered yet.
         * Send a KILL message upstream to the server it came from  */
        sendcmdto_one(&me, CMD_KILL, sptr, "%s :%s (Nick collision)", parv[parc-2], cli_name(&me));
      } 
      /* If the two have the same TS then we want to kill both sides, so
       * don't leave yet!
       */
      if (lastnick != cli_lastnick(acptr))
        return 0;                /* Ignore the NICK */
    }
    send_reply(acptr, ERR_NICKCOLLISION, nick);
  }

  ++ServerStats->is_kill;
  SetFlag(acptr, FLAG_KILLED);
  
  if (lastnick == cli_lastnick(acptr))
    samelastnick = 1;
    
  /*
   * This exits the client we had before getting the NICK message
   */
  if (differ) {
    sendcmdto_serv_butone(&me, CMD_KILL, NULL, "%C :%s (older nick "
			  "overruled)", acptr, cli_name(&me));
    if (MyConnect(acptr)) {
      sendcmdto_one(acptr, CMD_QUIT, cptr, ":Killed (%s (older "
		    "nick overruled))",  feature_str(FEAT_HIS_SERVERNAME));
      sendcmdto_one(&me, CMD_KILL, acptr, "%C :%s (older nick "
		    "overruled)", acptr, feature_str(FEAT_HIS_SERVERNAME));
    }

    exit_client_msg(cptr, acptr, &me, "Killed (%s (older nick "
		    "overruled))", feature_str(FEAT_HIS_SERVERNAME));
  }
  else {
    sendcmdto_serv_butone(&me, CMD_KILL, NULL, "%C :%s (nick collision from "
			  "same user@host)", acptr, cli_name(&me));
    if (MyConnect(acptr)) {
      sendcmdto_one(acptr, CMD_QUIT, cptr, ":Killed (%s (nick "
		    "collision from same user@host))",
		    feature_str(FEAT_HIS_SERVERNAME));
      sendcmdto_one(&me, CMD_KILL, acptr, "%C :%s (older nick "
		    "overruled)", acptr, feature_str(FEAT_HIS_SERVERNAME));
    }
    exit_client_msg(cptr, acptr, &me, "Killed (%s (nick collision from "
		    "same user@host))", feature_str(FEAT_HIS_SERVERNAME));
  }
  if (samelastnick)
    return 0;

  assert(0 != sptr);
  return set_nick_name(cptr, sptr, nick, parc, parv);
}
Exemple #5
0
/*
 * ms_svsnick - server message handler
 * parv[0] = sender prefix
 * parv[1] = Target numeric
 * parv[2] = New nickname
 */
int ms_svsnick(struct Client* cptr, struct Client* sptr, int parc, char* parv[])
{
  struct Client* acptr = NULL;
  struct Client* acptr2 = NULL;
  char		 nick[NICKLEN + 2];
  char*		 arg;

  if (parc < 3)
    return need_more_params(sptr, "SVSNICK"); 

  if (!(acptr = findNUser(parv[1])))
    return 0; /* Ignore SVSNICK for a user that has quit */

  if (ircd_strcmp(cli_name(acptr), parv[2]) == 0)
    return 0; /* Nick already set to what SVSNICK wants, ignoring... */

  /*
   * Basic sanity checks
   */

  /*
   * Don't let them make us send back a really long string of
   * garbage
   */
  arg = parv[2];
  if (strlen(arg) > IRCD_MIN(NICKLEN, feature_int(FEAT_NICKLEN)))
    arg[IRCD_MIN(NICKLEN, feature_int(FEAT_NICKLEN))] = '\0';

  strcpy(nick, arg);

  /*
   * If do_nick_name() returns a null name then reject it.
   */
  if (0 == do_nick_name(nick))
    return 0;

  /*
   * Check if this is a LOCAL user trying to use a reserved (Juped)
   * nick, if so tell him that it's a nick in use...
   */
  if (isNickJuped(nick))
    return 0;                        /* NICK message ignored */

  if (feature_bool(FEAT_OPER_SINGLELETTERNICK) && !IsAnOper(acptr)
      && nick[1] == '\0')
    return 0;

  /*
   * Set acptr2 to the client pointer of any user with nick's name.
   * If the user is the same as the person being svsnick'ed, let it
   * through as it is probably a change in the nickname's case.
   */
  if ((acptr2 = FindClient(nick))) {
    /*
     * If acptr == acptr2, then we have a client doing a nick
     * change between *equivalent* nicknames as far as server
     * is concerned (user is changing the case of his/her
     * nickname or somesuch), so we let it through :)
     */
    if (acptr != acptr2) {
      /* Nick collision occured, kill user with specific reason */
      ++ServerStats->is_kill;
      /* ??? - Why do we use cptr here? */
      SetFlag(cptr, FLAG_KILLED);
      exit_client(cptr, acptr2, &me, "Killed (Nickname Enforcement)");
    }
  }

  set_nick_name(acptr, acptr, nick, parc, parv, 1);
  sendcmdto_serv_butone(sptr, CMD_SVSNICK, cptr, "%s %s", parv[1], nick);
  return 0;
}