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189935b1 | 1 | /* |
2 | * IRC - Internet Relay Chat, ircd/whowas.c | |
3 | * Copyright (C) 1990 Markku Savela | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation; either version 1, or (at your option) | |
8 | * any later version. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program; if not, write to the Free Software | |
17 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
18 | * | |
19 | * --- avalon --- 6th April 1992 | |
20 | * rewritten to scrap linked lists and use a table of structures which | |
21 | * is referenced like a circular loop. Should be faster and more efficient. | |
22 | * | |
23 | * --- comstud --- 25th March 1997 | |
24 | * Everything rewritten from scratch. Avalon's code was bad. My version | |
25 | * is faster and more efficient. No more hangs on /squits and you can | |
26 | * safely raise NICKNAMEHISTORYLENGTH to a higher value without hurting | |
27 | * performance. | |
28 | * | |
29 | * --- comstud --- 5th August 1997 | |
30 | * Fixed for Undernet.. | |
31 | * | |
32 | * --- Run --- 27th August 1997 | |
33 | * Speeded up the code, added comments. | |
34 | */ | |
35 | #include "config.h" | |
36 | ||
37 | #include "whowas.h" | |
38 | #include "client.h" | |
39 | #include "ircd.h" | |
40 | #include "ircd_alloc.h" | |
41 | #include "ircd_chattr.h" | |
42 | #include "ircd_features.h" | |
43 | #include "ircd_log.h" | |
44 | #include "ircd_string.h" | |
45 | #include "list.h" | |
46 | #include "numeric.h" | |
47 | #include "s_debug.h" | |
48 | #include "s_misc.h" | |
49 | #include "s_user.h" | |
50 | #include "send.h" | |
51 | #include "struct.h" | |
52 | #include "sys.h" | |
53 | #include "msg.h" | |
54 | ||
55 | /* #include <assert.h> -- Now using assert in ircd_log.h */ | |
56 | #include <stdlib.h> | |
57 | #include <string.h> | |
58 | ||
59 | ||
60 | /** Keeps track of whowas least-recently-used list. */ | |
61 | static struct { | |
62 | struct Whowas *ww_list; /**< list of whowas structures */ | |
63 | struct Whowas *ww_tail; /**< tail of list for getting structures */ | |
64 | unsigned int ww_alloc; /**< alloc count */ | |
65 | } wwList = { 0, 0, 0 }; | |
66 | ||
67 | /** Hash table of Whowas entries by nickname. */ | |
68 | struct Whowas* whowashash[WW_MAX]; | |
69 | ||
70 | /** @file | |
71 | * @brief Manipulation functions for the whowas list. | |
9f8856e9 | 72 | * @version $Id: whowas.c,v 1.17.2.1 2006/03/25 03:46:56 entrope Exp $ |
189935b1 | 73 | * |
74 | * Since the introduction of numeric nicks (at least for upstream messages, | |
75 | * like MODE +o <nick>, KICK #chan <nick>, KILL <nick> etc), there is no | |
76 | * real important reason for a nick history anymore. | |
77 | * Nevertheless, there are two reason why we might want to keep it: | |
78 | * @li The /WHOWAS command, which is often useful to catch harassing | |
79 | * users or abusers in general. | |
80 | * @li Clients still use the normal nicks in the client-server protocol, | |
81 | * and it might be considered a nice feature that here we still have | |
82 | * nick chasing. | |
83 | * | |
84 | * Note however that BOTH reasons make it redundant to keep a whowas history | |
85 | * for users that split off. | |
86 | * | |
87 | * The rewrite of comstud was many to safe cpu during net.breaks and therefore | |
88 | * a bit redundant imho (Run). | |
89 | * | |
90 | * But - it was written anyway. So lets look at the structure of the | |
91 | * whowas history now: | |
92 | * | |
93 | * We still have a static table of 'struct Whowas' structures in which we add | |
94 | * new nicks (plus info) as in a rotating buffer. We keep a global pointer | |
95 | * `whowas_next' that points to the next entry to be overwritten - or to | |
96 | * the oldest entry in the table (which is the same). | |
97 | * | |
98 | * Each entry keeps pointers for two doubly linked lists (thus four pointers): | |
99 | * A list of the entries that have the same hash value ('hashv list'), and | |
100 | * a list of the entries that have the same online pointer (`online list'). | |
101 | * Note that the last list (pointers) is only updated as long as online points | |
102 | * to the corresponding client: As soon as the client signs off, this list | |
103 | * is not anymore maintained (and hopefully not used anymore either ;). | |
104 | * | |
105 | * So now we have two ways of accessing this database: | |
106 | * @li Given a <nick> we can calculate a hashv and then whowashash[hashv] will | |
107 | * point to the start of the 'hash list': all entries with the same hashv. | |
108 | * We'll have to search this list to find the entry with the correct <nick>. | |
109 | * Once we found the correct whowas entry, we have a pointer to the | |
110 | * corresponding client - if still online - for nick chasing purposes. | |
111 | * Note that the same nick can occur multiple times in the whowas history, | |
112 | * each of these having the same hash value of course. While a /WHOWAS on | |
113 | * just a nick will return all entries, nick chasing will only find the | |
114 | * first in the list. Because new entries are added at the start of the | |
115 | * 'hash list' we will always find the youngest entry, which is what we want. | |
116 | * @li Given an online client we have a pointer to the first whowas entry | |
117 | * of the linked list of whowas entries that all belong to this client. | |
118 | * We ONLY need this to reset all `online' pointers when this client | |
119 | * signs off. | |
120 | * | |
121 | * 27/8/97: | |
122 | * | |
123 | * Note that following: | |
124 | * | |
125 | * @li We *only* (need to) change the 'hash list' and the 'online' list | |
126 | * in add_history(). | |
127 | * @li There we always ADD an entry to the BEGINNING of the 'hash list' | |
128 | * and the 'online list': *new* entries are at the start of the lists. | |
129 | * The oldest entries are at the end of the lists. | |
130 | * @li We always REMOVE the oldest entry we have (whowas_next), this means | |
131 | * that this is always an entry that is at the *end* of the 'hash list' | |
132 | * and 'online list' that it is a part of: the next pointer will | |
133 | * always be NULL. | |
134 | * @li The previous pointer is *only* used to update the next pointer of the | |
135 | * previous entry, therefore we could better use a pointer to this | |
136 | * next pointer: That is faster - saves us a 'if' test (it will never be | |
137 | * NULL because the last added entry will point to the pointer that | |
138 | * points to the start of the list) and we won't need special code to | |
139 | * update the list start pointers. | |
140 | * | |
141 | * I incorporated these considerations into the code below. | |
142 | * | |
143 | * --Run | |
144 | */ | |
145 | ||
146 | /** Unlink a Whowas structure and free everything inside it. | |
147 | * @param[in,out] ww The whowas record to free. | |
148 | * @return The pointer \a ww. | |
149 | */ | |
150 | static struct Whowas * | |
151 | whowas_clean(struct Whowas *ww) | |
152 | { | |
153 | if (!ww) | |
154 | return 0; | |
155 | ||
156 | Debug((DEBUG_LIST, "Cleaning whowas structure for %s", ww->name)); | |
157 | ||
158 | if (ww->online) { /* unlink from client */ | |
159 | if (ww->cnext) /* shouldn't happen, but I'm not confident of that */ | |
160 | ww->cnext->cprevnextp = ww->cprevnextp; | |
161 | *ww->cprevnextp = ww->cnext; | |
162 | } | |
163 | ||
164 | if (ww->hnext) /* now unlink from hash table */ | |
165 | ww->hnext->hprevnextp = ww->hprevnextp; | |
166 | *ww->hprevnextp = ww->hnext; | |
167 | ||
168 | if (ww->wnext) /* unlink from whowas linked list... */ | |
169 | ww->wnext->wprev = ww->wprev; | |
170 | if (ww->wprev) | |
171 | ww->wprev->wnext = ww->wnext; | |
172 | ||
173 | if (wwList.ww_tail == ww) /* update tail pointer appropriately */ | |
174 | wwList.ww_tail = ww->wprev; | |
175 | ||
176 | /* Free old info */ | |
177 | if (ww->name) | |
178 | MyFree(ww->name); | |
179 | if (ww->username) | |
180 | MyFree(ww->username); | |
181 | if (ww->hostname) | |
182 | MyFree(ww->hostname); | |
183 | if (ww->realhost) | |
184 | MyFree(ww->realhost); | |
185 | if (ww->servername) | |
186 | MyFree(ww->servername); | |
187 | if (ww->realname) | |
188 | MyFree(ww->realname); | |
189 | if (ww->away) | |
190 | MyFree(ww->away); | |
191 | ||
192 | return ww; | |
193 | } | |
194 | ||
195 | /** Clean and free a whowas record. | |
196 | * @param[in] ww Whowas record to free. | |
197 | */ | |
198 | static void | |
199 | whowas_free(struct Whowas *ww) | |
200 | { | |
201 | if (!ww) | |
202 | return; | |
203 | ||
204 | Debug((DEBUG_LIST, "Destroying whowas structure for %s", ww->name)); | |
205 | ||
206 | whowas_clean(ww); | |
207 | MyFree(ww); | |
208 | ||
209 | wwList.ww_alloc--; | |
210 | } | |
211 | ||
189935b1 | 212 | /** Return a fresh Whowas record. |
213 | * If the total number of records is smaller than determined by | |
214 | * FEAT_NICKNAMEHISTORYLENGTH, allocate a new one. Otherwise, | |
215 | * reuse the oldest record in use. | |
216 | * @return A pointer to a clean Whowas. | |
217 | */ | |
218 | static struct Whowas * | |
219 | whowas_alloc(void) | |
220 | { | |
9f8856e9 | 221 | struct Whowas *ww; |
222 | ||
223 | if (wwList.ww_alloc >= feature_int(FEAT_NICKNAMEHISTORYLENGTH)) { | |
224 | /* reclaim the oldest whowas entry */ | |
225 | ww = whowas_clean(wwList.ww_tail); | |
226 | } else { | |
227 | /* allocate a new one */ | |
228 | wwList.ww_alloc++; | |
229 | ww = (struct Whowas *) MyMalloc(sizeof(struct Whowas)); | |
230 | } | |
189935b1 | 231 | |
9f8856e9 | 232 | assert(ww != NULL); |
233 | memset(ww, 0, sizeof(*ww)); | |
234 | return ww; | |
189935b1 | 235 | } |
236 | ||
237 | /** If necessary, trim the whowas list. | |
238 | * This function trims the whowas list until it contains no more than | |
239 | * FEAT_NICKNAMEHISTORYLENGTH records. | |
240 | */ | |
241 | void | |
242 | whowas_realloc(void) | |
243 | { | |
244 | Debug((DEBUG_LIST, "whowas_realloc() called with alloc count %d, " | |
245 | "history length %d, tail pointer %p", wwList.ww_alloc, | |
246 | feature_int(FEAT_NICKNAMEHISTORYLENGTH), wwList.ww_tail)); | |
247 | ||
248 | while (wwList.ww_alloc > feature_int(FEAT_NICKNAMEHISTORYLENGTH)) { | |
249 | if (!wwList.ww_tail) { /* list is empty... */ | |
250 | Debug((DEBUG_LIST, "whowas list emptied with alloc count %d", | |
251 | wwList.ww_alloc)); | |
252 | return; | |
253 | } | |
254 | ||
255 | whowas_free(wwList.ww_tail); /* free oldest element of whowas list */ | |
256 | } | |
257 | } | |
258 | ||
259 | /** Add a client to the whowas list. | |
260 | * @param[in] cptr Client to add. | |
261 | * @param[in] still_on If non-zero, link the record to the client's personal history. | |
262 | */ | |
263 | void add_history(struct Client *cptr, int still_on) | |
264 | { | |
265 | struct Whowas *ww; | |
266 | ||
267 | if (!(ww = whowas_alloc())) | |
268 | return; /* couldn't get a structure */ | |
269 | ||
270 | ww->hashv = hash_whowas_name(cli_name(cptr)); /* initialize struct */ | |
271 | ww->logoff = CurrentTime; | |
272 | DupString(ww->name, cli_name(cptr)); | |
273 | DupString(ww->username, cli_user(cptr)->username); | |
274 | DupString(ww->hostname, cli_user(cptr)->host); | |
275 | if (HasHiddenHost(cptr)) | |
276 | DupString(ww->realhost, cli_user(cptr)->realhost); | |
277 | DupString(ww->servername, cli_name(cli_user(cptr)->server)); | |
278 | DupString(ww->realname, cli_info(cptr)); | |
279 | if (cli_user(cptr)->away) | |
280 | DupString(ww->away, cli_user(cptr)->away); | |
281 | ||
282 | if (still_on) { /* user changed nicknames... */ | |
283 | ww->online = cptr; | |
284 | if ((ww->cnext = cli_whowas(cptr))) | |
285 | ww->cnext->cprevnextp = &ww->cnext; | |
286 | ww->cprevnextp = &(cli_whowas(cptr)); | |
287 | cli_whowas(cptr) = ww; | |
288 | } else /* user quit */ | |
289 | ww->online = 0; | |
290 | ||
291 | /* link new whowas structure to list */ | |
292 | ww->wnext = wwList.ww_list; | |
293 | if (wwList.ww_list) | |
294 | wwList.ww_list->wprev = ww; | |
295 | wwList.ww_list = ww; | |
296 | ||
297 | if (!wwList.ww_tail) /* update the tail pointer... */ | |
298 | wwList.ww_tail = ww; | |
299 | ||
300 | /* Now link it into the hash table */ | |
301 | if ((ww->hnext = whowashash[ww->hashv])) | |
302 | ww->hnext->hprevnextp = &ww->hnext; | |
303 | ww->hprevnextp = &whowashash[ww->hashv]; | |
304 | whowashash[ww->hashv] = ww; | |
305 | } | |
306 | ||
307 | /** Clear all Whowas::online pointers that point to a client. | |
308 | * @param[in] cptr Client who is going offline. | |
309 | */ | |
310 | void off_history(const struct Client *cptr) | |
311 | { | |
312 | struct Whowas *temp; | |
313 | ||
314 | for (temp = cli_whowas(cptr); temp; temp = temp->cnext) | |
315 | temp->online = NULL; | |
316 | } | |
317 | ||
318 | /** Find a client who has recently used a particular nickname. | |
319 | * @param[in] nick Nickname to find. | |
320 | * @param[in] timelimit Maximum age for entry. | |
321 | * @return User's online client, or NULL if none is found. | |
322 | */ | |
323 | struct Client *get_history(const char *nick, time_t timelimit) | |
324 | { | |
325 | struct Whowas *temp = whowashash[hash_whowas_name(nick)]; | |
326 | timelimit = CurrentTime - timelimit; | |
327 | ||
328 | for (; temp; temp = temp->hnext) | |
329 | if (0 == ircd_strcmp(nick, temp->name) && temp->logoff > timelimit) | |
330 | return temp->online; | |
331 | ||
332 | return NULL; | |
333 | } | |
334 | ||
335 | /** Count memory used by whowas list. | |
336 | * @param[out] wwu Number of entries in whowas list. | |
337 | * @param[out] wwum Total number of bytes used by nickname, username, | |
338 | * hostname and servername fields. | |
339 | * @param[out] wwa Number of away strings in whowas list. | |
340 | * @param[out] wwam Total number of bytes used by away strings. | |
341 | */ | |
342 | void count_whowas_memory(int *wwu, size_t *wwum, int *wwa, size_t *wwam) | |
343 | { | |
344 | struct Whowas *tmp; | |
345 | int u = 0; | |
346 | int a = 0; | |
347 | size_t um = 0; | |
348 | size_t am = 0; | |
349 | assert(0 != wwu); | |
350 | assert(0 != wwum); | |
351 | assert(0 != wwa); | |
352 | assert(0 != wwam); | |
353 | ||
354 | for (tmp = wwList.ww_list; tmp; tmp = tmp->wnext) { | |
355 | u++; | |
356 | um += (strlen(tmp->name) + 1); | |
357 | um += (strlen(tmp->username) + 1); | |
358 | um += (strlen(tmp->hostname) + 1); | |
359 | um += (strlen(tmp->servername) + 1); | |
360 | if (tmp->away) { | |
361 | a++; | |
362 | am += (strlen(tmp->away) + 1); | |
363 | } | |
364 | } | |
365 | *wwu = u; | |
366 | *wwum = um; | |
367 | *wwa = a; | |
368 | *wwam = am; | |
369 | } | |
370 | ||
371 | /** Initialize whowas table. */ | |
372 | void initwhowas(void) | |
373 | { | |
374 | int i; | |
375 | ||
376 | for (i = 0; i < WW_MAX; i++) | |
377 | whowashash[i] = 0; | |
378 | } | |
379 | ||
380 | /** Calculate a hash value for a string. | |
381 | * @param[in] name Nickname to calculate hash over. | |
382 | * @return Calculated hash value. | |
383 | */ | |
384 | unsigned int hash_whowas_name(const char *name) | |
385 | { | |
386 | unsigned int hash = 0; | |
387 | unsigned int hash2 = 0; | |
388 | unsigned char lower; | |
389 | ||
390 | do | |
391 | { | |
392 | lower = ToLower(*name); | |
393 | hash = (hash << 1) + lower; | |
394 | hash2 = (hash2 >> 1) + lower; | |
395 | } | |
396 | while (*++name); | |
397 | ||
398 | return ((hash & WW_MAX_INITIAL_MASK) << BITS_PER_COL) + | |
399 | (hash2 & BITS_PER_COL_MASK); | |
400 | } | |
401 |