--- /dev/null
+/*
+ * IRC - Internet Relay Chat, ircd/whowas.c
+ * Copyright (C) 1990 Markku Savela
+ *
+ * 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 1, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * --- avalon --- 6th April 1992
+ * rewritten to scrap linked lists and use a table of structures which
+ * is referenced like a circular loop. Should be faster and more efficient.
+ *
+ * --- comstud --- 25th March 1997
+ * Everything rewritten from scratch. Avalon's code was bad. My version
+ * is faster and more efficient. No more hangs on /squits and you can
+ * safely raise NICKNAMEHISTORYLENGTH to a higher value without hurting
+ * performance.
+ *
+ * --- comstud --- 5th August 1997
+ * Fixed for Undernet..
+ *
+ * --- Run --- 27th August 1997
+ * Speeded up the code, added comments.
+ */
+#include "config.h"
+
+#include "whowas.h"
+#include "client.h"
+#include "ircd.h"
+#include "ircd_alloc.h"
+#include "ircd_chattr.h"
+#include "ircd_features.h"
+#include "ircd_log.h"
+#include "ircd_string.h"
+#include "list.h"
+#include "numeric.h"
+#include "s_debug.h"
+#include "s_misc.h"
+#include "s_user.h"
+#include "send.h"
+#include "struct.h"
+#include "sys.h"
+#include "msg.h"
+
+/* #include <assert.h> -- Now using assert in ircd_log.h */
+#include <stdlib.h>
+#include <string.h>
+
+
+/** Keeps track of whowas least-recently-used list. */
+static struct {
+ struct Whowas *ww_list; /**< list of whowas structures */
+ struct Whowas *ww_tail; /**< tail of list for getting structures */
+ unsigned int ww_alloc; /**< alloc count */
+} wwList = { 0, 0, 0 };
+
+/** Hash table of Whowas entries by nickname. */
+struct Whowas* whowashash[WW_MAX];
+
+/** @file
+ * @brief Manipulation functions for the whowas list.
+ * @version $Id$
+ *
+ * Since the introduction of numeric nicks (at least for upstream messages,
+ * like MODE +o <nick>, KICK #chan <nick>, KILL <nick> etc), there is no
+ * real important reason for a nick history anymore.
+ * Nevertheless, there are two reason why we might want to keep it:
+ * @li The /WHOWAS command, which is often useful to catch harassing
+ * users or abusers in general.
+ * @li Clients still use the normal nicks in the client-server protocol,
+ * and it might be considered a nice feature that here we still have
+ * nick chasing.
+ *
+ * Note however that BOTH reasons make it redundant to keep a whowas history
+ * for users that split off.
+ *
+ * The rewrite of comstud was many to safe cpu during net.breaks and therefore
+ * a bit redundant imho (Run).
+ *
+ * But - it was written anyway. So lets look at the structure of the
+ * whowas history now:
+ *
+ * We still have a static table of 'struct Whowas' structures in which we add
+ * new nicks (plus info) as in a rotating buffer. We keep a global pointer
+ * `whowas_next' that points to the next entry to be overwritten - or to
+ * the oldest entry in the table (which is the same).
+ *
+ * Each entry keeps pointers for two doubly linked lists (thus four pointers):
+ * A list of the entries that have the same hash value ('hashv list'), and
+ * a list of the entries that have the same online pointer (`online list').
+ * Note that the last list (pointers) is only updated as long as online points
+ * to the corresponding client: As soon as the client signs off, this list
+ * is not anymore maintained (and hopefully not used anymore either ;).
+ *
+ * So now we have two ways of accessing this database:
+ * @li Given a <nick> we can calculate a hashv and then whowashash[hashv] will
+ * point to the start of the 'hash list': all entries with the same hashv.
+ * We'll have to search this list to find the entry with the correct <nick>.
+ * Once we found the correct whowas entry, we have a pointer to the
+ * corresponding client - if still online - for nick chasing purposes.
+ * Note that the same nick can occur multiple times in the whowas history,
+ * each of these having the same hash value of course. While a /WHOWAS on
+ * just a nick will return all entries, nick chasing will only find the
+ * first in the list. Because new entries are added at the start of the
+ * 'hash list' we will always find the youngest entry, which is what we want.
+ * @li Given an online client we have a pointer to the first whowas entry
+ * of the linked list of whowas entries that all belong to this client.
+ * We ONLY need this to reset all `online' pointers when this client
+ * signs off.
+ *
+ * 27/8/97:
+ *
+ * Note that following:
+ *
+ * @li We *only* (need to) change the 'hash list' and the 'online' list
+ * in add_history().
+ * @li There we always ADD an entry to the BEGINNING of the 'hash list'
+ * and the 'online list': *new* entries are at the start of the lists.
+ * The oldest entries are at the end of the lists.
+ * @li We always REMOVE the oldest entry we have (whowas_next), this means
+ * that this is always an entry that is at the *end* of the 'hash list'
+ * and 'online list' that it is a part of: the next pointer will
+ * always be NULL.
+ * @li The previous pointer is *only* used to update the next pointer of the
+ * previous entry, therefore we could better use a pointer to this
+ * next pointer: That is faster - saves us a 'if' test (it will never be
+ * NULL because the last added entry will point to the pointer that
+ * points to the start of the list) and we won't need special code to
+ * update the list start pointers.
+ *
+ * I incorporated these considerations into the code below.
+ *
+ * --Run
+ */
+
+/** Unlink a Whowas structure and free everything inside it.
+ * @param[in,out] ww The whowas record to free.
+ * @return The pointer \a ww.
+ */
+static struct Whowas *
+whowas_clean(struct Whowas *ww)
+{
+ if (!ww)
+ return 0;
+
+ Debug((DEBUG_LIST, "Cleaning whowas structure for %s", ww->name));
+
+ if (ww->online) { /* unlink from client */
+ if (ww->cnext) /* shouldn't happen, but I'm not confident of that */
+ ww->cnext->cprevnextp = ww->cprevnextp;
+ *ww->cprevnextp = ww->cnext;
+ }
+
+ if (ww->hnext) /* now unlink from hash table */
+ ww->hnext->hprevnextp = ww->hprevnextp;
+ *ww->hprevnextp = ww->hnext;
+
+ if (ww->wnext) /* unlink from whowas linked list... */
+ ww->wnext->wprev = ww->wprev;
+ if (ww->wprev)
+ ww->wprev->wnext = ww->wnext;
+
+ if (wwList.ww_tail == ww) /* update tail pointer appropriately */
+ wwList.ww_tail = ww->wprev;
+
+ /* Free old info */
+ if (ww->name)
+ MyFree(ww->name);
+ if (ww->username)
+ MyFree(ww->username);
+ if (ww->hostname)
+ MyFree(ww->hostname);
+ if (ww->realhost)
+ MyFree(ww->realhost);
+ if (ww->servername)
+ MyFree(ww->servername);
+ if (ww->realname)
+ MyFree(ww->realname);
+ if (ww->away)
+ MyFree(ww->away);
+
+ return ww;
+}
+
+/** Clean and free a whowas record.
+ * @param[in] ww Whowas record to free.
+ */
+static void
+whowas_free(struct Whowas *ww)
+{
+ if (!ww)
+ return;
+
+ Debug((DEBUG_LIST, "Destroying whowas structure for %s", ww->name));
+
+ whowas_clean(ww);
+ MyFree(ww);
+
+ wwList.ww_alloc--;
+}
+
+/** Return a fresh Whowas record.
+ * If the total number of records is smaller than determined by
+ * FEAT_NICKNAMEHISTORYLENGTH, allocate a new one. Otherwise,
+ * reuse the oldest record in use.
+ * @return A pointer to a clean Whowas.
+ */
+static struct Whowas *
+whowas_alloc(void)
+{
+ struct Whowas *ww;
+
+ if (wwList.ww_alloc >= feature_int(FEAT_NICKNAMEHISTORYLENGTH)) {
+ /* reclaim the oldest whowas entry */
+ ww = whowas_clean(wwList.ww_tail);
+ } else {
+ /* allocate a new one */
+ wwList.ww_alloc++;
+ ww = (struct Whowas *) MyMalloc(sizeof(struct Whowas));
+ }
+
+ assert(ww != NULL);
+ memset(ww, 0, sizeof(*ww));
+ return ww;
+}
+
+/** If necessary, trim the whowas list.
+ * This function trims the whowas list until it contains no more than
+ * FEAT_NICKNAMEHISTORYLENGTH records.
+ */
+void
+whowas_realloc(void)
+{
+ Debug((DEBUG_LIST, "whowas_realloc() called with alloc count %d, "
+ "history length %d, tail pointer %p", wwList.ww_alloc,
+ feature_int(FEAT_NICKNAMEHISTORYLENGTH), wwList.ww_tail));
+
+ while (wwList.ww_alloc > feature_int(FEAT_NICKNAMEHISTORYLENGTH)) {
+ if (!wwList.ww_tail) { /* list is empty... */
+ Debug((DEBUG_LIST, "whowas list emptied with alloc count %d",
+ wwList.ww_alloc));
+ return;
+ }
+
+ whowas_free(wwList.ww_tail); /* free oldest element of whowas list */
+ }
+}
+
+/** Add a client to the whowas list.
+ * @param[in] cptr Client to add.
+ * @param[in] still_on If non-zero, link the record to the client's personal history.
+ */
+void add_history(struct Client *cptr, int still_on)
+{
+ struct Whowas *ww;
+
+ if (!(ww = whowas_alloc()))
+ return; /* couldn't get a structure */
+
+ ww->hashv = hash_whowas_name(cli_name(cptr)); /* initialize struct */
+ ww->logoff = CurrentTime;
+ DupString(ww->name, cli_name(cptr));
+ DupString(ww->username, cli_user(cptr)->username);
+ DupString(ww->hostname, cli_user(cptr)->host);
+ if (HasHiddenHost(cptr))
+ DupString(ww->realhost, cli_user(cptr)->realhost);
+ DupString(ww->servername, cli_name(cli_user(cptr)->server));
+ DupString(ww->realname, cli_info(cptr));
+ if (cli_user(cptr)->away)
+ DupString(ww->away, cli_user(cptr)->away);
+
+ if (still_on) { /* user changed nicknames... */
+ ww->online = cptr;
+ if ((ww->cnext = cli_whowas(cptr)))
+ ww->cnext->cprevnextp = &ww->cnext;
+ ww->cprevnextp = &(cli_whowas(cptr));
+ cli_whowas(cptr) = ww;
+ } else /* user quit */
+ ww->online = 0;
+
+ /* link new whowas structure to list */
+ ww->wnext = wwList.ww_list;
+ if (wwList.ww_list)
+ wwList.ww_list->wprev = ww;
+ wwList.ww_list = ww;
+
+ if (!wwList.ww_tail) /* update the tail pointer... */
+ wwList.ww_tail = ww;
+
+ /* Now link it into the hash table */
+ if ((ww->hnext = whowashash[ww->hashv]))
+ ww->hnext->hprevnextp = &ww->hnext;
+ ww->hprevnextp = &whowashash[ww->hashv];
+ whowashash[ww->hashv] = ww;
+}
+
+/** Clear all Whowas::online pointers that point to a client.
+ * @param[in] cptr Client who is going offline.
+ */
+void off_history(const struct Client *cptr)
+{
+ struct Whowas *temp;
+
+ for (temp = cli_whowas(cptr); temp; temp = temp->cnext)
+ temp->online = NULL;
+}
+
+/** Find a client who has recently used a particular nickname.
+ * @param[in] nick Nickname to find.
+ * @param[in] timelimit Maximum age for entry.
+ * @return User's online client, or NULL if none is found.
+ */
+struct Client *get_history(const char *nick, time_t timelimit)
+{
+ struct Whowas *temp = whowashash[hash_whowas_name(nick)];
+ timelimit = CurrentTime - timelimit;
+
+ for (; temp; temp = temp->hnext)
+ if (0 == ircd_strcmp(nick, temp->name) && temp->logoff > timelimit)
+ return temp->online;
+
+ return NULL;
+}
+
+/** Count memory used by whowas list.
+ * @param[out] wwu Number of entries in whowas list.
+ * @param[out] wwum Total number of bytes used by nickname, username,
+ * hostname and servername fields.
+ * @param[out] wwa Number of away strings in whowas list.
+ * @param[out] wwam Total number of bytes used by away strings.
+ */
+void count_whowas_memory(int *wwu, size_t *wwum, int *wwa, size_t *wwam)
+{
+ struct Whowas *tmp;
+ int u = 0;
+ int a = 0;
+ size_t um = 0;
+ size_t am = 0;
+ assert(0 != wwu);
+ assert(0 != wwum);
+ assert(0 != wwa);
+ assert(0 != wwam);
+
+ for (tmp = wwList.ww_list; tmp; tmp = tmp->wnext) {
+ u++;
+ um += (strlen(tmp->name) + 1);
+ um += (strlen(tmp->username) + 1);
+ um += (strlen(tmp->hostname) + 1);
+ um += (strlen(tmp->servername) + 1);
+ if (tmp->away) {
+ a++;
+ am += (strlen(tmp->away) + 1);
+ }
+ }
+ *wwu = u;
+ *wwum = um;
+ *wwa = a;
+ *wwam = am;
+}
+
+/** Initialize whowas table. */
+void initwhowas(void)
+{
+ int i;
+
+ for (i = 0; i < WW_MAX; i++)
+ whowashash[i] = 0;
+}
+
+/** Calculate a hash value for a string.
+ * @param[in] name Nickname to calculate hash over.
+ * @return Calculated hash value.
+ */
+unsigned int hash_whowas_name(const char *name)
+{
+ unsigned int hash = 0;
+ unsigned int hash2 = 0;
+ unsigned char lower;
+
+ do
+ {
+ lower = ToLower(*name);
+ hash = (hash << 1) + lower;
+ hash2 = (hash2 >> 1) + lower;
+ }
+ while (*++name);
+
+ return ((hash & WW_MAX_INITIAL_MASK) << BITS_PER_COL) +
+ (hash2 & BITS_PER_COL_MASK);
+}
+
projects / ircu2.10.12-pk.git / blobdiff