memory leak in server.c monitor_add() / monitor_del() ?

[michaelortmann]

Reviewing eggdrop for memory leaks i found suspicious code here:

I didnt check in real life, but looking at the source code, my understanding is:

monitor_add() allocates memory for a list member:

https://github.com/eggheads/eggdrop/blob/develop/src/mod/server.mod/server.c#L1244C12-L1245

but monitor_del() doesnt free that memory when it deletes a member from the list:

https://github.com/eggheads/eggdrop/blob/develop/src/mod/server.mod/server.c#L1284-L1292

if this is a real bug it could be related to or the same as #1545 (but unlikely coze this this bug would be older than eggdrop 1.9.2, see #1173 and #1545 (comment)))

please check if this is a real world memory leak.

a fix could look like (untested!):

/* Remove nickname from monitor list */
static int monitor_del (char *nick) {
  struct monitor_list *current = monitor;
  struct monitor_list *previous = NULL;

  while (current && rfc_casecmp(current->nick, nick)) {
    previous = current;
    current = current->next;
  }
  if (!current)
    return 1;
  if (current == monitor)
    monitor = current->next;
  else
    previous->next = current->next;
  nfree(current);

  dprintf(DP_SERVER, "MONITOR - %s\n", nick);
  return 0;
}

we have could also use the existing egg_list_delete(), but its not worth it here, because we would still have to search for nick and free the node. for eggdrop 2.0 we could change the mod API to provide a more generic egg_list, like egg_list_delete(list, cmp_func, free_func) that could handle all search and freeing needs. probably overkill ;)