path: root/functions.c

/*
 * This file is part of blabouncer (https://www.blatech.co.uk/l_bratch/blabouncer).
 * Copyright (C) 2019 Luke Bratch <luke@bratch.co.uk>.
 *
 * Blabouncer 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, version 3.
 *
 * Blabouncer 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 blabouncer. If not, see <http://www.gnu.org/licenses/>.
*/

#include "functions.h"

// Global debug control
extern int debug;
extern char debugpath[PATH_MAX];
extern int background;

// Internal function just to replace nick in server greeting strings
// (as in ":servername 00x oldnick :Blablabla" -> ":servername 00x newnick :Blablabla")
void updategreetingnick(char *greeting, char *greetingnum, char *newnick, char *oldnick) {
  debugprint(DEBUG_FULL, "updategreetingnick(): '%s' '%s' '%s' '%s'.\n", greeting, greetingnum, newnick, oldnick);

  // Find the position of the old nick in the current greeting
  char searchstr[MAXDATASIZE];
  snprintf(searchstr, MAXDATASIZE, " %s %s :", greetingnum, oldnick);
  char *ret;
  ret = strstr(greeting, searchstr);

  // If ret not found, try again without the colon (e.g. for greeting 004)
  if (ret == NULL) {
    snprintf(searchstr, MAXDATASIZE, " %s %s ", greetingnum, oldnick);
    ret = strstr(greeting, searchstr);
  }

  // Perhaps the new nick is already present (seen for instance when connecting to another bouncer like Miau)
  if (ret == NULL) {
    snprintf(searchstr, MAXDATASIZE, " %s %s ", greetingnum, newnick);
    ret = strstr(greeting, searchstr);
    if (ret != NULL) {
      debugprint(DEBUG_FULL, "updategreetingnick(): newnick is already present, returning.\n");
      return;
    }
  }

  // If ret *still* not found, abandon ship
  if (ret == NULL) {
    debugprint(DEBUG_CRIT, "Error updating greeting string, substring not found.  Exiting!\n");
    printf("Error updating greeting string, substring not found.  Exiting!\n");
    exit(1);
  }

  int pos = ret - greeting + 5; // +5 for " 001 "

  // Copy the start of the old greeting into a new string
  char greetingtmp[MAXDATASIZE];
  strncpy(greetingtmp, greeting, pos);
  // Terminate it
  greetingtmp[pos] = '\0';

  // Now smash everything (start of old greeting + new nick + remainder of old greeting)
  // together into the new greeting, put in a new temporary string
  char greetingtmp2[MAXDATASIZE];
  if (!snprintf(greetingtmp2, MAXDATASIZE, "%s%s %s", greetingtmp, newnick, greeting + pos + strlen(oldnick) + 1)) {
    fprintf(stderr, "Error while preparing new greeting string!\n");
    debugprint(DEBUG_CRIT, "Error while preparing new greeting string!\n");
    exit(1);
  }

  // And finally copy back to source string
  strcpy(greeting, greetingtmp2);

  debugprint(DEBUG_FULL, "updategreetingnick(): Built new greeting '%s' '%s', length '%ld'.\n", greetingnum, greeting, strlen(greeting));
}

// Write debug string to file.
// Debug level is provided by level, set to one of DEBUG_CRIT, DEBUG_SOME or DEBUG_FULL.
// Debug is only written if the global int "debug" is greater than or equal to the level.
void debugprint(int level, char *format, ...) {
  // Stop here if the user's debug level is less than the level of the current message
  if (debug < level) return;

  if (strlen(debugpath) < 1) {
    // debugpath isn't set, we can't do anything here
    return;
  }

  va_list args;
  va_start(args, format);

  FILE *fp;
  int bytes = 0;
  fp = fopen(debugpath, "a");

  if (fp == NULL) {
    printf("Couldn't open debugpath '%s'!\n", debugpath);
    return;
  }

  // Prepend a timestamp to each line
  time_t rawtime;
  struct tm * timeinfo;
  time(&rawtime);
  timeinfo = localtime(&rawtime);
  // Strip the trailing newline
  char timestr[MAXCHAR];
  snprintf(timestr, MAXCHAR, "%s", asctime(timeinfo));
  timestr[strlen(timestr) - 1] = '\0';
  if ((bytes = fprintf(fp, "%s: ", timestr)) < 0) {
    debugprint(DEBUG_CRIT, "error: could not write timestamp to debug file.\n"); // TODO - This might not be useful if we can't write
  }

  if ((bytes = vfprintf(fp, format, args)) < 0) {
    debugprint(DEBUG_CRIT, "error: could not write to debug file.\n"); // TODO - This might not be useful if we can't write
  }
  fclose(fp);

  va_end(args);
}

// Get stdin line with buffer overrun protection
int getstdin(char *prompt, char *buff, size_t sz) {
  int ch, extra;

  // Print optional prompt
  if (prompt != NULL) {
    printf ("%s", prompt);
    fflush (stdout);
  }

  // Get the intput from stdin
  if (fgets (buff, sz, stdin) == NULL) {
    return NO_INPUT;
  }

  // If it was too long, there'll be no newline. In that case, we flush
  // to end of line so that excess doesn't affect the next call.
  if (buff[strlen(buff) - 1] != '\n') { // strlen of the actually entered line, not the original array size
    extra = 0;
    while (((ch = getchar()) != '\n') && (ch != EOF)) {
      extra = 1;
    }
    return (extra == 1) ? TOO_LONG : OK;
  }

  // Otherwise remove newline and give string back to caller.
  buff[strlen(buff) - 1] = '\0';
  return OK;
}

// Append CR-LF to the end of a string (after cleaning up any existing trailing CR or LF)
void appendcrlf(char *string) {
  // Make sure it doesn't already end with CR or LF
  // (But only if string is at least two characters long already)
  if (strlen(string) >= 2) {
    while (string[strlen(string) - 1] == '\r' || string[strlen(string) - 1] == '\n') {
      string[strlen(string) - 1] = '\0';
    }
  }

  int startlen = strlen(string);
  string[startlen] = '\r'; // Add CR
  string[startlen + 1] = '\n'; // Add LF
  string[startlen + 2] = '\0'; // Finish with null terminator
}

// Remove leading colon ':' which is the starting character of a prefix in an IRC message
void stripprefix(char *string) {
  // Make a copy to work with
  char string2[strlen(string)];

  debugprint(DEBUG_FULL, "stripprefix(): starting with '%s', strlen: %zd.\n", string, strlen(string));

  // Don't bother if this isn't a prefix with a leading ':'
  if (string[0] != ':') {
    debugprint(DEBUG_FULL, "stripprefix(): no leading ':', returning.\n");
    return;
  }

  // Copy the old string into a new one, but...
  for (size_t i = 1; i < strlen(string); i++) {
    string2[i - 1] = string[i];
  }

  // Copy result back to original string
  strncpy(string, string2, strlen(string) - 1);

  // Finish with null terminator
  string[strlen(string) - 1] = '\0';

  debugprint(DEBUG_FULL, "stripprefix(): finishing with '%s', strlen: %zd.\n", string, strlen(string));
}

// Extract final parameter from IRC message, removing the leading colon ':'
// e.g. given this string:
// ":irc.tghost.co.uk 332 blabounce #test :This is a test topic!"
// We want to end up with:
// "This is a test topic!"
void extractfinalparameter(char *string) {
  // Make a copy to work with
  char string2[strlen(string)];

  // Position of colon
  int colonpos = -1;

  debugprint(DEBUG_FULL, "extractfinalparameter(): starting with '%s', strlen: %zd.\n", string, strlen(string));

  // Strip the colon at position 0 if there is one
  stripprefix(string);

  // Find the colon
  for (size_t i = 0; i < strlen(string); i++) {
    if (string[i] == ':') {
      debugprint(DEBUG_FULL, "Found colon at position %zd!\n", i);
      colonpos = i;
      break;
    }
  }

  if (colonpos == -1) {
    debugprint(DEBUG_FULL, "no colon found, returning\n");
    return;
  }

  // Build a new string starting from the next position after the colon
  int counter = 0;
  for (size_t i = colonpos + 1; i < strlen(string); i++) {
    string2[counter] = string[i];
    counter++;
  }

  // Copy result back to original string
  strncpy(string, string2, counter);

  // Finish with null terminator
  string[counter] = '\0';

  debugprint(DEBUG_FULL, "extractfinalparameter(): finishing with '%s', strlen: %zd.\n", string, strlen(string));
}

// Extract the IRC nick from a prefix
// e.g. given this string:
// ":foo!bar@baz"
// We want to end up with:
// "foo"
void extractnickfromprefix(char *string) {
  // Position of bang
  int bangpos = -1;

  debugprint(DEBUG_FULL, "extractnickfromprefix(): starting with '%s', strlen: %zd.\n", string, strlen(string));

  // Strip the colon at position 0 if there is one
  stripprefix(string);

  // Find the bang
  for (size_t i = 0; i < strlen(string); i++) {
    if (string[i] == '!') {
      debugprint(DEBUG_FULL, "Found bang at position %zd!\n", i);
      bangpos = i;
      break;
    }
  }

  if (bangpos == -1) {
    debugprint(DEBUG_FULL, "no bang found, returning\n");
    return;
  }

  // Terminate the string at whatever position we found the bang
  string[bangpos] = '\0';

  debugprint(DEBUG_FULL, "extractnickfromprefix(): finishing with '%s', strlen: %zd.\n", string, strlen(string));
}

// Update an existing nickuserhost string with a new nick
void updatenickuserhost(char *nickuserhost, char *nick) {
  debugprint(DEBUG_FULL, "updatenickuserhost(): updating '%s' with '%s'.\n", nickuserhost, nick);

  // Position of bang
  int bangpos = -1;

  // Find the bang
  for (size_t i = 0; i < strlen(nickuserhost); i++) {
    if (nickuserhost[i] == '!') {
      debugprint(DEBUG_FULL, "Found bang at position %ld!\n", i);
      bangpos = i;
      break;
    }
  }

  if (bangpos == -1) {
    debugprint(DEBUG_FULL, "No bang found in existing nickuserhost, quitting!\n");
    return;
  }

  // Make a new string combining the nick nick and the old nickuserhost + the offset of the bang
  char newstr[MAXDATASIZE];
  snprintf(newstr, MAXDATASIZE, "%s%s", nick, nickuserhost + bangpos);
  newstr[strlen(nickuserhost) - bangpos + strlen(nick)] = '\0';

  // Copy back to source string
  strcpy(nickuserhost, newstr);

  debugprint(DEBUG_FULL, "updatenickuserhost(): new nickuserhost '%s', length '%ld'.\n", nickuserhost, strlen(nickuserhost));
}

// Update existing greeting strings with a new nickuserhost and new nick
void updategreetings(char *greeting001, char *greeting002, char *greeting003, char *greeting004, char *greeting005a, char *greeting005b,
                     char *greeting005c, char *newnickuserhost, char *oldnickuserhost, char *newnick, char *oldnick) {
  debugprint(DEBUG_FULL, "updategreetings(): updating greetings with new nickuserhost '%s' and nick '%s'.\n", newnickuserhost, newnick);

  // nickuserhost and greeting001's final component first
  // (final component as in ":servername 001 nick :Blablabla final!com@ponent"

  // Make copies of the nickuserhosts to work with
  char newnickuserhostcpy[MAXDATASIZE];
  strcpy(newnickuserhostcpy, newnickuserhost);
  stripprefix(newnickuserhostcpy);
  char oldnickuserhostcpy[MAXDATASIZE];
  strcpy(oldnickuserhostcpy, oldnickuserhost);
  stripprefix(oldnickuserhostcpy);

  // Find the position of the old nickuserhost in the current greeting 001
  char *ret;
  ret = strstr(greeting001, oldnickuserhostcpy);
  int pos = ret - greeting001;

  // Terminate greeting001 where the nickuserhost begins
  greeting001[pos] = '\0';

  // Stick the new nickuserhost in place in a temporary greeting 001 string
  char greetingtmp[MAXDATASIZE];
  snprintf(greetingtmp, MAXDATASIZE, "%s%s", greeting001, newnickuserhostcpy);

  // Terminate it
  greetingtmp[pos + strlen(newnickuserhostcpy)] = '\0';

  // Copy back to source greeting 001
  strcpy(greeting001, greetingtmp);

  debugprint(DEBUG_FULL, "updategreetings(): new greeting 001 '%s', length '%ld'.\n", greeting001, strlen(greeting001));

  // Get the new nick

  char newnickcpy[MAXDATASIZE];
  strcpy(newnickcpy, newnick);
  extractnickfromprefix(newnickcpy);

  // greeting nicks next
  // (as in ":servername 00x oldnick :Blablabla" -> ":servername 00x newnick :Blablabla")
  updategreetingnick(greeting001, "001", newnickcpy, oldnick);
  updategreetingnick(greeting002, "002", newnickcpy, oldnick);
  updategreetingnick(greeting003, "003", newnickcpy, oldnick);
  updategreetingnick(greeting004, "004", newnickcpy, oldnick);
  if (greeting005a[0]) {
    updategreetingnick(greeting005a, "005", newnickcpy, oldnick);
  }
  if (greeting005b[0]) {
    updategreetingnick(greeting005b, "005", newnickcpy, oldnick);
  }
  if (greeting005c[0]) {
    updategreetingnick(greeting005c, "005", newnickcpy, oldnick);
  }
}

// Return index of requested client FD within the clients array.
// TODO - Use this wherever we are calculating the position (various places) instead of
// duplicating code.
int arrindex(struct client *clients, int clientfd) {
  // Find the client in the clients array and make sure they are authenticated
  for (int i = 0; i < MAXCLIENTS; i++) {
    if (clients[i].fd == clientfd) {
      return i;
    }
  }

  // Something went wrong, we didn't find it
  return 0;
}

// Send whatever string to a specific client by providing the FD
// If "bypass" == 1 then permit sending to client even if unauthenticated (for instance for a CAP LS response)
int sendtoclient(int fd, char *strsrc, struct client *clients, struct settings *settings, int bypass) {
  // Copy to new string for passing to appendcrlf() to avoid overrun in appendcrlf()
  char str[MAXDATASIZE];
  strcpy(str, strsrc);

  appendcrlf(str); // Do this just before sending so callers don't need to worry about it

  int i = 0;
  // Find the client in the clients array and make sure they are authenticated
  for (i = 0; i < MAXCLIENTS; i++) {
    if (clients[i].fd == fd) {
      // Found client in array, check authentication status
      if (!clients[i].authed && !bypass) {
        debugprint(DEBUG_SOME, "sendtoclient(): skipping unauthenticated client with fd %d.\n", clients[i].fd);
        return 0;
      }
      // Break when we get to the correct fd, "i" is now the position in the clients array of our client
      break;
    }
  }

  debugprint(DEBUG_SOME, "sendtoclient(): sending \"%s\" (length %zd) to client with fd %d.\n", str, strlen(str), fd);
  if (socksend(clients[i].ssl, str, strlen(str), settings->clienttls) == -1) {
    perror("error: sendtoclient() socksend()\n");
    debugprint(DEBUG_CRIT, "error: sendtoclient() socksend() error sending to client with fd '%d', errno '%d'.\n", fd, errno);
    return 0;
  }

  return 1;
}

// Relay/send message to all clients (optionally except one)
// "except" is used to send to all clients _except_ the fd provided (except = 0 (EXCEPT_NONE) avoids this, i.e. sends to all)
// "except" is really the "sourcefd" and is also used as part of the authentication check - this is messy and they should perhaps be two separate arguments.
int sendtoallclients(struct client *clients, char *strsrc, int except, struct settings *settings) {

  char *sendertype;

  // Copy to new string for passing to appendcrlf() to avoid overrun in appendcrlf()
  char str[MAXDATASIZE];
  strcpy(str, strsrc);

  appendcrlf(str); // Do this just before sending so callers don't need to worry about it

  // Decide what sort of text to prefix the debug output with
  // At the moment if non-zero "except" is specified then it must be a message from a bouncer client
  // and if "except" is zero then it must be a message from the real IRC server
  if (except) {
    sendertype = "bouncer-client";
  } else {
    sendertype = "bouncer-server";
  }

  // Find the sending client in the clients array and make sure they are authenticated
  for (int i = 0; i < MAXCLIENTS; i++) {
    // Trust clientfd of 0, only we can set that ourselves
    if (!except) {
      debugprint(DEBUG_FULL, "sendtoallclients(): trusting clientfd of 0.\n");
      break;
    }
    if (clients[i].fd == except) {
      // Found client in array, check authentication status
      if (!clients[i].authed) {
        debugprint(DEBUG_SOME, "sendtoallclients(): skipping unauthenticated client with fd %d.\n", clients[i].fd);
        return 0;
      }
    }
  }

  // Relay/send to all clients...
  for (int i = 0; i < MAXCLIENTS; i++) {
    // Skip the current client if "except" non-zero (no need to send back to itself)
    if (clients[i].fd == except) {
      continue;
    }
    // ...but only if they are connected...
    if (clients[i].fd > 0) {
      // ...and authenticated
      if (!clients[i].authed) {
        debugprint(DEBUG_SOME, "sendtoallclients(): skipping unauthenticated client with fd %d.\n", clients[i].fd);
        continue;
      }
      debugprint(DEBUG_SOME, "sendtoallclients(): %s: sending '%s' to client with fd %d.\n", sendertype, str, clients[i].fd);
      if (socksend(clients[i].ssl, str, strlen(str), settings->clienttls) == -1) {
        perror("error: sendtoallclients() socksend()\n");
        debugprint(DEBUG_CRIT, "error: sendtoallclients() socksend() error sending to client with fd '%d', errno '%d'.\n", clients[i].fd, errno);
      }
    }
  }

  return 1;
}

// Send whatever string to the real IRC server
// Client FD and arrays needed to make sure anything relayed from a client is from an authenticated client.
// clientfd of "0" means trusted, used when we are sending things ourselves that weren't relayed
// from a real client.
int sendtoserver(SSL *server_ssl, char *strsrc, int str_len, int clientfd, struct client *clients, struct settings *settings) {
  // Copy to new string for passing to appendcrlf() to avoid overrun in appendcrlf()
  char str[MAXDATASIZE];
  strcpy(str, strsrc);

  appendcrlf(str); // Do this just before sending so callers don't need to worry about it
  str_len = strlen(str); // Recalculate str_len in case it changed (TODO: so do we even need to pass it to this function?)

  // Find the sending client in the clients array and make sure they are authenticated
  for (int i = 0; i < MAXCLIENTS; i++) {
    // Trust clientfd of 0, only we can set that ourselves
    if (!clientfd) {
      debugprint(DEBUG_FULL, "sendtoserver(): trusting clientfd of 0.\n");
      break;
    }
    if (clients[i].fd == clientfd) {
      // Found client in array, check authentication status
      if (!clients[i].authed) {
        debugprint(DEBUG_SOME, "sendtoserver(): skipping unauthenticated client with fd %d.\n", clients[i].fd);
        return 0;
      }
    }
  }

  debugprint(DEBUG_SOME, "sendtoserver(): sending '%s' to IRC server (length %d).\n", str, str_len);
  if (socksend(server_ssl, str, str_len, settings->servertls) == -1) {
    printf("error: sendtoserver() socksend()\n");
    debugprint(DEBUG_CRIT, "error: sendtoserver() socksend() error sending to server, errno '%d'.\n", clientfd, errno);
    return 0;
  }

  return 1;
}

// Disconnect the client fd "fd" by close()ing it and remove
// it from the array of clients.
// Also set its authentication and registration statuses to 0.
// Also set the pending statuses to 0
int disconnectclient(int fd, struct client *clients, struct ircdstate *ircdstate, struct settings *settings) {
  debugprint(DEBUG_SOME, "disconnectclient(): disconnecting client fd '%d'\n", fd);

  // Alert other clients about the disconnection (don't send yet, we haven't removed from the clients array yet)
  char alertmsg[MAXDATASIZE];
  if (!snprintf(alertmsg, MAXDATASIZE, "NOTICE %s :blabouncer: client with fd %d has disconnected.", ircdstate->ircnick, fd)) {
    fprintf(stderr, "Error while preparing authentication failure NOTICE!\n");
    debugprint(DEBUG_CRIT, "Error while preparing authentication failure NOTICE!\n");
    alertmsg[0] = '\0';
  }
  // Remove the client from the clients array
  for (int i = 0; i < MAXCLIENTS; i++) {
    if (clients[i].fd == fd) {
      debugprint(DEBUG_FULL, "found and clearing fd %d from clients[%d]\n", fd, i);
      clients[i].fd = 0;
      clients[i].authed = 0;
      clients[i].registered = 0;
      clients[i].pendingchannelmode = 0;
      clients[i].pendingban = 0;
      clients[i].pendingwho = 0;
      clients[i].pendinglist = 0;
      clients[i].pendingwhois = 0;
      clients[i].pendingwhowas = 0;
      clients[i].pendingnames = 0;
      clients[i].pendingcap = 0;
      if (settings->clienttls) {
        // Finish up with OpenSSL if using client TLS
        SSL_free(clients[i].ssl);
      }
      // Close the socket
      close(fd);
      // Now clients array is cleared, inform all other clients (source "0" since we trust this message)
      sendtoallclients(clients, alertmsg, 0, settings);
      return 1;
    }
  }

  // If we got here, we didn't find and clear the client
  // TODO - Do something with a failed return code
  return 0;
}

int createchannel(struct channel *channels, char *name, char *topic, char *topicwho, char *topicwhen) {
  debugprint(DEBUG_FULL, "createchannel(): given '%s', '%s', '%s', and '%s'.\n", name, topic, topicwho, topicwhen);

  // Make sure the channel doesn't already exist
  for (int i = 0; i < MAXCHANNELS; i++) {
    if (strncmp(channels[i].name, name, strlen(name)) == 0) {
      // Note that this may be happening because we just reconnected
      debugprint(DEBUG_CRIT, "error: createchannel(): channel name already exists.\n");
      return 0;
      break;
    }
  }

  // Find a free slot in the array (when the channel name is not set (0th character is '\0'))...
  for (int i = 0; i < MAXCHANNELS; i++) {
    if (!channels[i].name[0]) {
      // ...and set the name and topic
      strncpy(channels[i].name, name, strlen(name));
      channels[i].name[strlen(name)] = '\0';
      debugprint(DEBUG_FULL, "createchannel(): name given was '%s', length '%ld'.\n", name, strlen(name));
      debugprint(DEBUG_FULL, "createchannel(): name set to '%s', length '%ld'.\n", channels[i].name, strlen(channels[i].name));
      strncpy(channels[i].topic, topic, strlen(topic));
      channels[i].topic[strlen(topic)] = '\0';
      debugprint(DEBUG_FULL, "createchannel(): topic given was '%s', length '%ld'.\n", topic, strlen(topic));
      debugprint(DEBUG_FULL, "createchannel(): topic set to '%s', length '%ld'.\n", channels[i].topic, strlen(channels[i].topic));
      strncpy(channels[i].topicwho, topicwho, strlen(topicwho));
      channels[i].topicwho[strlen(topicwho)] = '\0';
      strncpy(channels[i].topicwhen, topicwhen, strlen(topicwhen));
      channels[i].topicwhen[strlen(topicwhen)] = '\0';
      channels[i].gotnames = 0;
      return 1;
      break; // TODO - This should be safe to remove since return is hit first
    }
  }

  debugprint(DEBUG_CRIT, "error: createchannel() didn't create a channel\n");

  // TODO - Make a failed return do something to callers
  return 0;
}

int setchanneltopicwhotime(struct channel *channels, char *channelname, char *who, char *when) {
  debugprint(DEBUG_FULL, "setchanneltopicwhotime(): given '%s', '%s', and '%s'.\n", channelname, who, when);

  debugprint(DEBUG_FULL, "setchanneltopicwhotime(): who: '%s' with length '%ld'.\n", who, strlen(who));
  debugprint(DEBUG_FULL, "setchanneltopicwhotime(): when: '%s' with length '%ld'.\n", when, strlen(when));

  for (int i = 0; i < MAXCHANNELS; i++) {
    if (strncmp(channels[i].name, channelname, strlen(channelname)) == 0) {
      strncpy(channels[i].topicwho, who, strlen(who));
      channels[i].topicwho[strlen(who)] = '\0';
      strncpy(channels[i].topicwhen, when, strlen(when));
      channels[i].topicwhen[strlen(when)] = '\0';
      return 1;
    }
  }

  // TODO - Make a failed return do something to callers
  return 0;
}

int setchanneltopic(struct channel *channels, char *channelname, char *topic) {
  debugprint(DEBUG_FULL, "setchanneltopic(): given '%s' and '%s'.\n", channelname, topic);

  for (int i = 0; i < MAXCHANNELS; i++) {
    if (strncmp(channels[i].name, channelname, strlen(channelname)) == 0) {
      strncpy(channels[i].topic, topic, strlen(topic));
      channels[i].topic[strlen(topic)] = '\0';
      return 1;
    }
  }

  // TODO - Make a failed return do something to callers
  return 0;
}

int getchannelcount(struct channel *channels) {
  int count = 0;

  for (int i = 0; i < MAXCHANNELS; i++) {
    if (channels[i].name[0]) {
      count++;
    }
  }

  debugprint(DEBUG_FULL, "getchannelcount(): counted %d channels.\n", count);

  return count;
}

int removechannel(struct channel *channels, char *name) {
  debugprint(DEBUG_FULL, "removechannel(): given '%s'.\n", name);

  // Clear its topic setter and timestamp...
  setchanneltopicwhotime(channels, name, "", "0");

  // Find the channel in the channel array...
  for (int i = 0; i < MAXCHANNELS; i++) {
    if (strncmp(channels[i].name, name, strlen(name)) == 0) {
      // ..and NULL its name (0th character = '\0')
      channels[i].name[0] = '\0';
      debugprint(DEBUG_FULL, "removechannel(): channel '%s' removed and topicwhen set to '%s'.\n", name, channels[i].topicwhen);
      return 1;
    }
  }

  debugprint(DEBUG_CRIT, "error: removechannel() didn't remove a channel\n");

  // TODO - Make a failed return do something to callers
  return 0;
}

// Check if we have the NAMES for the channel 'name' already.
// Return the 1 if we do, 0 if we don't, or -1 if there's an error.
int channelgotnames(struct channel *channels, char *name) {
  debugprint(DEBUG_FULL, "channelgotnames(): given '%s'.\n", name);
  for (int i = 0; i < MAXCHANNELS; i++) {
    if (strncmp(channels[i].name, name, strlen(name)) == 0) {
      if (channels[i].gotnames) {
        debugprint(DEBUG_FULL, "channelgotnames(): channel '%s' gotnames was set, returning '%d'.\n", channels[i].name, channels[i].gotnames);
        return 1;
      } else {
        debugprint(DEBUG_FULL, "channelgotnames(): channel '%s' gotnames was not set, returning '%d'.\n", channels[i].name, channels[i].gotnames);
        return 0;
      }
    }
  }

  // We didn't find the channel, this isn't good!  TODO - Do something if this happens.
  debugprint(DEBUG_CRIT, "channelgotnames(): channel '%s' not found, this is bad, returning -1.\n", name);
  return -1;
}

// Check if we are in a channel named "name" or not.
// Return 1 if we are, or 0 if not.
int inchannel(struct channel *channels, char *name) {
  // Make sure the name doesn't have any trailing CR or LF
  // (But only if name is at least two characters long already)
  if (strlen(name) >= 2) {
    while (name[strlen(name) - 1] == '\r' || name[strlen(name) - 1] == '\n') {
      name[strlen(name) - 1] = '\0';
    }
  }

  for (int i = 0; i < MAXCHANNELS; i++) {
    if (strncmp(channels[i].name, name, strlen(name)) == 0) {
      debugprint(DEBUG_FULL, "inchannel(): in channel '%s'.\n", name);
      return 1;
    }
  }

  // We're not in the channel
  debugprint(DEBUG_FULL, "inchannel(): NOT in channel '%s'.\n", name);
  return 0;
}

// Returns the array index in the 'channels' array of the channel
// named 'channel'.
// Returns -1 if there was an error.
int channelindex(struct channel *channels, char *name) {
  debugprint(DEBUG_FULL, "channelindex(): given '%s'.\n", name);
  for (int i = 0; i < MAXCHANNELS; i++) {
    if (strncmp(channels[i].name, name, strlen(name)) == 0) {
      return i;
    }
  }

  // We didn't find the channel, this isn't good!  TODO - Do something if this happens.
  debugprint(DEBUG_CRIT, "channelindex(): channel '%s' not found, this is bad, returning -1.\n", name);
  return -1;
}

// Send the requested number of lines of replay log to the requested client.
// 'sourcefd' is the client to send to, and replayseconds is the number of
// seconds of replay log to replay.
// Returns 1 for success or 0 for failure.
int doreplay(int sourcefd, int replayseconds, struct client *clients, struct settings *settings, struct ircdstate *ircdstate, struct channel *channels) {
  char outgoingmsg[MAXDATASIZE];

  // Figure out how many lines to replay
  int numlines = replaylines(replayseconds, settings->basedir);
  debugprint(DEBUG_FULL, "Replay log lines: '%d'.\n", numlines);

  if (numlines < 0) {
    debugprint(DEBUG_CRIT, "Error getting number of replay lines.\n");
    return 0;
  } else if (numlines == 0) {
    snprintf(outgoingmsg, MAXDATASIZE, "NOTICE %s :0 replay log lines found in the time requested, nothing to send.", ircdstate->ircnick);
    sendtoclient(sourcefd, outgoingmsg, clients, settings, 0);
    return 1;
  }

  // Announce the start
  snprintf(outgoingmsg, MAXDATASIZE, "NOTICE %s :Starting log replay....", ircdstate->ircnick);
  sendtoclient(sourcefd, outgoingmsg, clients, settings, 0);

  // Replay those lines!
  for (int i = 0; i < numlines; i++) {
    if (!readreplayline(replayseconds, i, outgoingmsg, settings->basedir)) {
      debugprint(DEBUG_CRIT, "Error requesting replay line.\n");
      return 0;
    }

    // Check if the replay line is a TOPIC, a JOIN, or a PART so we don't
    // replay those if we are not currently in the channel they are from
    // otherwise clients and state go a bit mad.
    // Never replay them if they are from us.

    // Copy to a temporary string
    char *strcopy = strdup(outgoingmsg);
    // Keep track of initial pointer for free()ing later
    char *strcopyPtr = strcopy;

    // Build array of each space-separated token
    char tokens[3][MAXDATASIZE];
    char *token;

    for (int j = 0; j < 3; j++) {
      // Try to split
      if ((token = strsep(&strcopy, " ")) == NULL) {
        debugprint(DEBUG_CRIT, "doreplay(): error splitting string on iteration '%d', returning!\n", j);
        return 0;
      }
      // Copy into the token array (strlen + 1 to get the NULL terminator)
      strncpy(tokens[j], token, strlen(token) + 1);
    }

    if (strncmp(tokens[1], "TOPIC", strlen("TOPIC")) == 0 ||
        strncmp(tokens[1], "JOIN", strlen("JOIN")) == 0 ||
        strncmp(tokens[1], "PART", strlen("PART")) == 0) {
      // Skip over colon if present in channel name
      int offset = 0;
      if (tokens[2][0] == ':') {
        offset = 1;
      }

      // To make sure it's not us
      extractnickfromprefix(tokens[0]);

      // Check if we're currently in this channel or if the log line is from us
      if (!inchannel(channels, tokens[2] + offset) || strncmp(tokens[0], ircdstate->ircnick, strlen(tokens[0])) == 0) {
        debugprint(DEBUG_FULL, "Not sending '%s' replay line '%s'.\n", tokens[1], outgoingmsg);
        free(strcopyPtr);
        continue;
      }
    }

    free(strcopyPtr);

    debugprint(DEBUG_FULL, "Sending replay line: '%s'.\n", outgoingmsg);
    sendtoclient(sourcefd, outgoingmsg, clients, settings, 0);
  }

  // Announce the end
  snprintf(outgoingmsg, MAXDATASIZE, "NOTICE %s :Log replay complete.", ircdstate->ircnick);
  sendtoclient(sourcefd, outgoingmsg, clients, settings, 0);

  return 1;
}

// Send the auto replay to the requested client, where 'sourcefd' is the client
// to send to.  The type of replay will depend on the user's settings.
// Returns 1 for success or 0 for failure.
int doautoreplay(int sourcefd, struct client *clients, struct settings *settings, struct ircdstate *ircdstate, struct channel *channels) {
  // If replaymode = "none" then don't send anything
  if (!strncmp(settings->replaymode, "none", strlen("none"))) {
    debugprint(DEBUG_FULL, "doautoreplay() requested but replaymode = \"none\".\n");
    return 1;
  }

  // If replaymode = "time" then send whatever replayseconds is set to
  if (!strncmp(settings->replaymode, "time", strlen("time"))) {
    debugprint(DEBUG_FULL, "doautoreplay(): replaymode = \"time\", calling doreplay() with '%d' seconds.\n", settings->replayseconds);
    if (!doreplay(sourcefd, settings->replayseconds, clients, settings, ircdstate, channels)) {
      debugprint(DEBUG_SOME, "doautoreplay(): doreplay() returned 0, returning 0 to caller...\n");
      return 0;
    }
    return 1;
  }

  // If replaymode = "lastspoke" then send whatever replayseconds is set to
  if (!strncmp(settings->replaymode, "lastspoke", strlen("lastspoke"))) {
    debugprint(DEBUG_FULL, "doautoreplay(): replaymode = \"lastspoke\".\n", settings->replayseconds);
    int secondsago = lastspokesecondsago(ircdstate->ircnick, settings->basedir);
    if (secondsago < 1) {
      debugprint(DEBUG_SOME, "doautoreplay(): lastspokesecondsago() returned < 1, returning 0 to caller...\n");
      return 0;
    }
    debugprint(DEBUG_FULL, "doautoreplay(): replaymode = \"lastspoke\", sending lines from '%d' seconds ago to sourcefd '%d'.\n", secondsago, sourcefd);
    if (!doreplay(sourcefd, secondsago, clients, settings, ircdstate, channels)) {
      debugprint(DEBUG_SOME, "doautoreplay(): doreplay() returned 0, returning 0 to caller...\n");
      return 0;
    }
    return 1;
  }

  // We shouldn't get here
  return 0;
}

// Return a count of the number of connected clients
int numclients(struct client *clients) {
  int count = 0;

  for (int i = 0; i < MAXCLIENTS; i++) {
    if (clients[i].fd) {
      count++;
    }
  }

  debugprint(DEBUG_FULL, "numclients(): '%d' clients connected.\n", count);
  return count;
}

// Join any channels that were configured to be automatically
// joined in the configuration file.
// Returns 1 on success or 0 on failure.
int joinautochannels(SSL *server_ssl, struct client *clients, struct settings *settings) {
  if (strlen(settings->autochannels) == 0) {
    // None configured
    debugprint(DEBUG_FULL, "joinautochannels(): none configured.\n");
    return 1;
  }

  // Split string up into each channel
  char tokens[MAXAUTOCHANLEN][MAXCHANLENGTH];
  int counter = 0;

  // Copy to a temporary string
  char *strcopy = strdup(settings->autochannels);
  // Keep track of initial pointer for free()ing later
  char *strcopyPtr = strcopy;

  char *token;

  // Split on commas
  while ((token = strsep(&strcopy, ",")) != NULL) {
    if (*token  == '\0') continue; // Skip consecutive matches
    if (counter >= MAXAUTOCHANLEN) break; // Too many tokens
    debugprint(DEBUG_FULL, "  >> Auto channel: '%s', length '%ld'.\n", token, strlen(token));
    // Copy into the token array (strlen + 1 to get the NULL terminator)
    strncpy(tokens[counter], token, strlen(token) + 1);
    if (strlen(tokens[counter]) > MAXCHANLENGTH) {
      printf("error: channel name '%s' from configuration file too long, max length is '%d'.\n", tokens[counter], MAXCHANLENGTH);
      debugprint(DEBUG_CRIT, "error: channel name '%s' from configuration file too long, max length is '%d'.\n", tokens[counter], MAXCHANLENGTH);
      exit(1);
    }
    counter++;
  }

  // Join all the channels
  for (int i = 0; i < counter; i++) {
    debugprint(DEBUG_FULL, "joinautochannels(): Joining '%s'.\n", tokens[i]);
    char joinmsg[MAXDATASIZE];
    snprintf(joinmsg, MAXDATASIZE, "JOIN %s", tokens[i]);
    sendtoserver(server_ssl, joinmsg, strlen(joinmsg), 0, clients, settings);
  }

  free(strcopyPtr);
  // TODO - Can we fail here?  Return 0 if so and make callers handle this if so.
  return 1;
}

// Try to make a new nick if no configured are available or liked by the server
// Do this by sticking a number on the end of the current nick and trying numbers
// 1 through to 9.
void tryautonick(struct ircdstate *ircdstate) {
  // Increment the attempts counter
  ircdstate->autonicknum++;

  if (ircdstate->autonicknum == 10) {
    // We've already tried 9 nicks and failed, give up
    printf("tryautonick(): Tried 9 automatic nicks and the server didn't like any, giving up.\n");
    debugprint(DEBUG_CRIT, "tryautonick(): Tried 9 automatic nicks and the server didn't like any, giving up.\n");
    exit(1);
  }

  int oldlen = strlen(ircdstate->ircnick);

  // If we've already started trying autonick, just replace the last character a the new number
  if (ircdstate->autonicknum > 1) {
    debugprint(DEBUG_FULL, "tryautonick(): already started autonick, starting with '%s' length '%ld'.\n", ircdstate->ircnick, strlen(ircdstate->ircnick));
    ircdstate->ircnick[oldlen - 1] = ircdstate->autonicknum + '0';
    // And null terminate
    ircdstate->ircnick[oldlen] = '\0';
  // If the nick is longer than or equal to the RFC 1459 max nick
  // length then try sticking the number at the end
  } else if (oldlen >= MAXRFCNICKLEN) {
    debugprint(DEBUG_FULL, "tryautonick(): long old nick, starting with '%s' length '%ld'.\n", ircdstate->ircnick, strlen(ircdstate->ircnick));
    // (+ '0' to make char from int)
    ircdstate->ircnick[MAXRFCNICKLEN] = ircdstate->autonicknum + '0';
    // And null terminate
    ircdstate->ircnick[MAXRFCNICKLEN + 1] = '\0';
  // Otherwise, just stick it on the end (+ '0' to make char from int)
  } else {
    debugprint(DEBUG_FULL, "tryautonick(): short old nick, starting with '%s' length '%ld'.\n", ircdstate->ircnick, strlen(ircdstate->ircnick));
    ircdstate->ircnick[oldlen] = ircdstate->autonicknum + '0';
    // And null terminate
    ircdstate->ircnick[oldlen + 1] = '\0';
  }

  debugprint(DEBUG_FULL, "tryautonick(): set irdstrings->ircnick to '%s'.\n", ircdstate->ircnick);
}

// Exit the program cleanly - tell clients, tell the server, then exit(0)
// Optional quit message string "quitmsg"
// "sourcefd" of 0 means the request didn't come from a client
void cleanexit(SSL *server_ssl, struct client *clients, int sourcefd, struct ircdstate *ircdstate, struct settings *settings, char *quitmsg) {
  char outgoingmsg[MAXDATASIZE];

  // Tell clients and debug log
  if (sourcefd) {
    snprintf(outgoingmsg, MAXDATASIZE, "NOTICE %s :Exiting on request from client with fd '%d', message '%s'.", ircdstate->ircnick, sourcefd, quitmsg);
    debugprint(DEBUG_CRIT, "Exiting on request from client with fd '%d', message '%s'.\n", sourcefd, quitmsg);
  } else {
    snprintf(outgoingmsg, MAXDATASIZE, "NOTICE %s :Exiting on request (not from a client), message '%s'.", ircdstate->ircnick, quitmsg);
    debugprint(DEBUG_CRIT, "Exiting on request (not from a client), message '%s'.\n", quitmsg);
  }
  sendtoallclients(clients, outgoingmsg, EXCEPT_NONE, settings);

  // Tell the server
  // Combine "QUIT :" with any (optional) quit message
  snprintf(outgoingmsg, MAXDATASIZE, "QUIT :%s", quitmsg);
  sendtoserver(server_ssl, outgoingmsg, strlen(outgoingmsg), sourcefd, clients, settings);

  exit(0);
}

// Re-read the configuration file, setting 'failuremsg' to a failure message on failure.
// Returns 1 on success or 0 on failure.
int rehash(struct settings *settings, char *failuremsg) {
  // TODO - Try to share some/all of this code with the initial main() settings loading

  // What is the auto replay mode?
  char oldreplaymode[MAXDATASIZE];
  strcpy(oldreplaymode, settings->replaymode);
  if (!getconfstr("replaymode", settings->conffile, settings->replaymode)) {
    strcpy(settings->replaymode, oldreplaymode);
    strcpy(failuremsg, "error getting 'replaymode' from configuration file");
    return 0;
  } else {
    if (strcmp(settings->replaymode, "none") && strcmp(settings->replaymode, "time") && strcmp(settings->replaymode, "lastspoke")) {
      strcpy(settings->replaymode, oldreplaymode);
      strcpy(failuremsg, "replaymode in configuration file must be one of \"none\", \"time\", or \"lastspoke\"");
      return 0;
    }
  }

  // How many seconds of replay log should automatically be replayed - TODO - Can we do error checking on this?
  int oldreplayseconds = settings->replayseconds;
  settings->replayseconds = getconfint("replayseconds", settings->conffile);
  if (errno == ECONFINT) {
    settings->replayseconds = oldreplayseconds;
    strcpy(failuremsg, "error getting 'replayseconds' from configuration file");
    return 0;
  }

  // Is logging enabled?
  int oldlogging = settings->logging;
  settings->logging = getconfint("logging", settings->conffile);
  if (errno == ECONFINT) {
    settings->logging = oldlogging;
    strcpy(failuremsg, "error getting 'logging' from configuration file");
    return 0;
  }

  // Is replay logging enabled?
  int oldreplaylogging = settings->replaylogging;
  settings->replaylogging = getconfint("replaylogging", settings->conffile);
  if (errno == ECONFINT) {
    settings->replaylogging = oldreplaylogging;
    strcpy(failuremsg, "error getting 'replaylogging' from configuration file");
    return 0;
  }

  // Is debugging enabled?
  int olddebug = debug;
  debug = getconfint("debug", settings->conffile);
  if (errno == ECONFINT) {
    debug = olddebug;
    strcpy(failuremsg, "error getting 'debug' from configuration file");
    return 0;
  }

  // All is good, no failure message, return 1.
  failuremsg[0] = '\0';
  return 1;
}