2 * Copyright 1998-1999 The OpenLDAP Foundation, All Rights Reserved.
3 * COPYING RESTRICTIONS APPLY, see COPYRIGHT file
6 * Copyright (c) 1993 The Regents of the University of Michigan.
9 * cache.c - local caching support for LDAP
17 #include <ac/socket.h>
18 #include <ac/string.h>
25 static int cache_hash LDAP_P(( BerElement *ber ));
26 static LDAPMessage *msg_dup LDAP_P(( LDAPMessage *msg ));
27 static int request_cmp LDAP_P(( BerElement *req1, BerElement *req2 ));
28 static int chain_contains_dn LDAP_P(( LDAPMessage *msg, char *dn ));
29 static long msg_size LDAP_P(( LDAPMessage *msg ));
30 static void check_cache_memused LDAP_P(( LDAPCache *lc ));
31 static void uncache_entry_or_req LDAP_P(( LDAP *ld, char *dn, int msgid ));
36 ldap_enable_cache( LDAP *ld, long timeout, long maxmem )
39 if ( ld->ld_cache == NULLLDCACHE ) {
40 if (( ld->ld_cache = (LDAPCache *)malloc( sizeof( LDAPCache )))
42 ld->ld_errno = LDAP_NO_MEMORY;
45 (void) memset( ld->ld_cache, 0, sizeof( LDAPCache ));
46 ld->ld_cache->lc_memused = sizeof( LDAPCache );
49 ld->ld_cache->lc_timeout = timeout;
50 ld->ld_cache->lc_maxmem = maxmem;
51 check_cache_memused( ld->ld_cache );
52 ld->ld_cache->lc_enabled = 1;
61 ldap_disable_cache( LDAP *ld )
64 if ( ld->ld_cache != NULLLDCACHE ) {
65 ld->ld_cache->lc_enabled = 0;
73 ldap_set_cache_options( LDAP *ld, unsigned long opts )
76 if ( ld->ld_cache != NULLLDCACHE ) {
77 ld->ld_cache->lc_options = opts;
84 ldap_destroy_cache( LDAP *ld )
87 if ( ld->ld_cache != NULLLDCACHE ) {
88 ldap_flush_cache( ld );
89 free( (char *)ld->ld_cache );
90 ld->ld_cache = NULLLDCACHE;
97 ldap_flush_cache( LDAP *ld )
101 LDAPMessage *m, *next;
103 Debug( LDAP_DEBUG_TRACE, "ldap_flush_cache\n", 0, 0, 0 );
105 if ( ld->ld_cache != NULLLDCACHE ) {
106 /* delete all requests in the queue */
107 for ( m = ld->ld_cache->lc_requests; m != NULLMSG; m = next ) {
111 ld->ld_cache->lc_requests = NULLMSG;
113 /* delete all messages in the cache */
114 for ( i = 0; i < LDAP_CACHE_BUCKETS; ++i ) {
115 for ( m = ld->ld_cache->lc_buckets[ i ];
116 m != NULLMSG; m = next ) {
120 ld->ld_cache->lc_buckets[ i ] = NULLMSG;
122 ld->ld_cache->lc_memused = sizeof( LDAPCache );
129 ldap_uncache_request( LDAP *ld, int msgid )
132 Debug( LDAP_DEBUG_TRACE, "ldap_uncache_request %d ld_cache %lx\n",
133 msgid, (long) ld->ld_cache, 0 );
135 uncache_entry_or_req( ld, NULL, msgid );
141 ldap_uncache_entry( LDAP *ld, char *dn )
144 Debug( LDAP_DEBUG_TRACE, "ldap_uncache_entry %s ld_cache %lx\n",
145 dn, (long) ld->ld_cache, 0 );
147 uncache_entry_or_req( ld, dn, 0 );
155 uncache_entry_or_req( LDAP *ld,
156 char *dn, /* if non-NULL, uncache entry */
157 int msgid ) /* request to uncache (if dn == NULL) */
160 LDAPMessage *m, *prev, *next;
162 Debug( LDAP_DEBUG_TRACE,
163 "ldap_uncache_entry_or_req dn %s msgid %d ld_cache %lx\n",
164 dn, msgid, (long) ld->ld_cache );
166 if ( ld->ld_cache == NULLLDCACHE ) {
170 /* first check the request queue */
172 for ( m = ld->ld_cache->lc_requests; m != NULLMSG; m = next ) {
174 if (( dn != NULL && chain_contains_dn( m, dn )) ||
175 ( dn == NULL && m->lm_msgid == msgid )) {
176 if ( prev == NULLMSG ) {
177 ld->ld_cache->lc_requests = next;
179 prev->lm_next = next;
181 ld->ld_cache->lc_memused -= msg_size( m );
188 /* now check the rest of the cache */
189 for ( i = 0; i < LDAP_CACHE_BUCKETS; ++i ) {
191 for ( m = ld->ld_cache->lc_buckets[ i ]; m != NULLMSG;
194 if (( dn != NULL && chain_contains_dn( m, dn )) ||
195 ( dn == NULL && m->lm_msgid == msgid )) {
196 if ( prev == NULLMSG ) {
197 ld->ld_cache->lc_buckets[ i ] = next;
199 prev->lm_next = next;
201 ld->ld_cache->lc_memused -= msg_size( m );
213 ldap_add_request_to_cache( LDAP *ld, unsigned long msgtype, BerElement *request )
219 Debug( LDAP_DEBUG_TRACE, "ldap_add_request_to_cache\n", 0, 0, 0 );
221 ld->ld_errno = LDAP_SUCCESS;
222 if ( ld->ld_cache == NULLLDCACHE ||
223 ( ld->ld_cache->lc_enabled == 0 )) {
227 if (( new = (LDAPMessage *) calloc( 1, sizeof(LDAPMessage) ))
229 if (( new->lm_ber = ldap_alloc_ber_with_options( ld )) == NULLBER ) {
233 len = request->ber_ptr - request->ber_buf;
234 if (( new->lm_ber->ber_buf = (char *) malloc( (size_t)len ))
236 ber_free( new->lm_ber, 0 );
238 ld->ld_errno = LDAP_NO_MEMORY;
241 SAFEMEMCPY( new->lm_ber->ber_buf, request->ber_buf,
243 new->lm_ber->ber_ptr = new->lm_ber->ber_buf;
244 new->lm_ber->ber_end = new->lm_ber->ber_buf + len;
245 new->lm_msgid = ld->ld_msgid;
246 new->lm_msgtype = msgtype;;
247 new->lm_next = ld->ld_cache->lc_requests;
248 ld->ld_cache->lc_requests = new;
250 ld->ld_errno = LDAP_NO_MEMORY;
257 ldap_add_result_to_cache( LDAP *ld, LDAPMessage *result )
260 LDAPMessage *m, **mp, *req, *new, *prev;
263 Debug( LDAP_DEBUG_TRACE, "ldap_add_result_to_cache: id %d, type %d\n",
264 result->lm_msgid, result->lm_msgtype, 0 );
266 if ( ld->ld_cache == NULLLDCACHE ||
267 ( ld->ld_cache->lc_enabled == 0 )) {
268 Debug( LDAP_DEBUG_TRACE, "artc: cache disabled\n", 0, 0, 0 );
272 if ( result->lm_msgtype != LDAP_RES_SEARCH_ENTRY &&
273 result->lm_msgtype != LDAP_RES_SEARCH_REFERENCE &&
274 result->lm_msgtype != LDAP_RES_SEARCH_RESULT &&
275 result->lm_msgtype != LDAP_RES_COMPARE ) {
277 * only cache search and compare operations
279 Debug( LDAP_DEBUG_TRACE,
280 "artc: only caching search & compare operations\n", 0, 0, 0 );
285 * if corresponding request is in the lc_requests list, add this
286 * result to it. if this result completes the results for the
287 * request, add the request/result chain to the cache proper.
290 for ( m = ld->ld_cache->lc_requests; m != NULL; m = m->lm_next ) {
291 if ( m->lm_msgid == result->lm_msgid ) {
297 if ( m != NULLMSG ) { /* found request; add to end of chain */
299 for ( ; m->lm_chain != NULLMSG; m = m->lm_chain )
301 if (( new = msg_dup( result )) != NULLMSG ) {
302 new->lm_chain = NULLMSG;
304 Debug( LDAP_DEBUG_TRACE,
305 "artc: result added to cache request chain\n",
308 if ( result->lm_msgtype == LDAP_RES_SEARCH_RESULT ||
309 result->lm_msgtype == LDAP_RES_COMPARE ) {
311 * this result completes the chain of results
312 * add to cache proper if appropriate
314 keep = 0; /* pessimistic */
315 err = ldap_result2error( ld, result, 0 );
316 if ( err == LDAP_SUCCESS ||
317 ( result->lm_msgtype == LDAP_RES_COMPARE &&
318 ( err == LDAP_COMPARE_FALSE ||
319 err == LDAP_COMPARE_TRUE ||
320 err == LDAP_NO_SUCH_ATTRIBUTE ))) {
324 if ( ld->ld_cache->lc_options == 0 ) {
325 if ( err == LDAP_SIZELIMIT_EXCEEDED ) {
328 } else if (( ld->ld_cache->lc_options &
329 LDAP_CACHE_OPT_CACHEALLERRS ) != 0 ) {
333 if ( prev == NULLMSG ) {
334 ld->ld_cache->lc_requests = req->lm_next;
336 prev->lm_next = req->lm_next;
340 Debug( LDAP_DEBUG_TRACE,
341 "artc: not caching result with error %d\n",
345 mp = &ld->ld_cache->lc_buckets[
346 cache_hash( req->lm_ber ) ];
349 req->lm_time = (long) time( NULL );
350 ld->ld_cache->lc_memused += msg_size( req );
351 check_cache_memused( ld->ld_cache );
352 Debug( LDAP_DEBUG_TRACE,
353 "artc: cached result with error %d\n",
358 Debug( LDAP_DEBUG_TRACE, "artc: msgid not in request list\n",
366 * look in the cache for this request
367 * return 0 if found, -1 if not
368 * if found, the corresponding result messages are added to the incoming
369 * queue with the correct (new) msgid so that subsequent ldap_result calls
373 ldap_check_cache( LDAP *ld, unsigned long msgtype, BerElement *request )
376 LDAPMessage *m, *new, *prev, *next;
379 unsigned long validtime;
381 Debug( LDAP_DEBUG_TRACE, "ldap_check_cache\n", 0, 0, 0 );
383 if ( ld->ld_cache == NULLLDCACHE ||
384 ( ld->ld_cache->lc_enabled == 0 )) {
388 reqber.ber_buf = reqber.ber_ptr = request->ber_buf;
389 reqber.ber_end = request->ber_ptr;
391 validtime = (long)time( NULL ) - ld->ld_cache->lc_timeout;
394 hash = cache_hash( &reqber );
395 for ( m = ld->ld_cache->lc_buckets[ hash ]; m != NULLMSG; m = next ) {
396 Debug( LDAP_DEBUG_TRACE,"cc: examining id %d,type %d\n",
397 m->lm_msgid, m->lm_msgtype, 0 );
398 if ( m->lm_time < validtime ) {
399 /* delete expired message */
401 if ( prev == NULL ) {
402 ld->ld_cache->lc_buckets[ hash ] = next;
404 prev->lm_next = next;
406 Debug( LDAP_DEBUG_TRACE, "cc: expired id %d\n",
408 ld->ld_cache->lc_memused -= msg_size( m );
411 if ( m->lm_msgtype == (int)msgtype &&
412 request_cmp( m->lm_ber, &reqber ) == 0 ) {
420 if ( m == NULLMSG ) {
425 * add duplicates of responses to incoming queue
428 for ( m = m->lm_chain; m != NULLMSG; m = m->lm_chain ) {
429 if (( new = msg_dup( m )) == NULLMSG ) {
433 new->lm_msgid = ld->ld_msgid;
434 new->lm_chain = NULLMSG;
436 new->lm_next = ld->ld_responses;
437 ld->ld_responses = new;
440 prev->lm_chain = new;
443 Debug( LDAP_DEBUG_TRACE, "cc: added type %d\n",
444 new->lm_msgtype, 0, 0 );
447 Debug( LDAP_DEBUG_TRACE, "cc: result returned from cache\n", 0, 0, 0 );
457 cache_hash( BerElement *ber )
463 * just take the length of the packet and mod with # of buckets
466 if ( ber_skip_tag( &bercpy, &len ) == LBER_ERROR
467 || ber_scanf( &bercpy, "x" ) == LBER_ERROR ) {
468 len = 0; /* punt: just return zero */
470 len = bercpy.ber_end - bercpy.ber_ptr;
473 Debug( LDAP_DEBUG_TRACE, "cache_hash: len is %ld, returning %ld\n",
474 len, len % LDAP_CACHE_BUCKETS, 0 );
475 return( (int) ( len % LDAP_CACHE_BUCKETS ));
480 msg_dup( LDAPMessage *msg )
485 if (( new = (LDAPMessage *)malloc( sizeof(LDAPMessage))) != NULL ) {
486 *new = *msg; /* struct copy */
487 if (( new->lm_ber = ber_dup( msg->lm_ber )) == NULLBER ) {
491 len = msg->lm_ber->ber_end - msg->lm_ber->ber_buf;
492 if (( new->lm_ber->ber_buf = (char *) malloc(
493 (size_t)len )) == NULL ) {
494 ber_free( new->lm_ber, 0 );
498 SAFEMEMCPY( new->lm_ber->ber_buf, msg->lm_ber->ber_buf,
500 new->lm_ber->ber_ptr = new->lm_ber->ber_buf +
501 ( msg->lm_ber->ber_ptr - msg->lm_ber->ber_buf );
502 new->lm_ber->ber_end = new->lm_ber->ber_buf + len;
510 request_cmp( BerElement *req1, BerElement *req2 )
515 r1 = *req1; /* struct copies */
519 * skip the enclosing tags (sequence markers) and the msg ids
521 if ( ber_skip_tag( &r1, &len ) == LBER_ERROR || ber_scanf( &r1, "x" )
525 if ( ber_skip_tag( &r2, &len ) == LBER_ERROR || ber_scanf( &r2, "x" )
531 * check remaining length and bytes if necessary
533 if (( len = r1.ber_end - r1.ber_ptr ) !=
534 (unsigned long) (r2.ber_end - r2.ber_ptr) )
536 return( -1 ); /* different lengths */
538 return( memcmp( r1.ber_ptr, r2.ber_ptr, (size_t)len ));
543 chain_contains_dn( LDAPMessage *msg, char *dn )
553 * first check the base or dn of the request
555 ber = *msg->lm_ber; /* struct copy */
556 if ( ber_scanf( &ber, "{i{a", &msgid, &s ) != LBER_ERROR ) {
557 rc = ( strcasecmp( dn, s ) == 0 ) ? 1 : 0;
564 if ( msg->lm_msgtype == LDAP_REQ_COMPARE ) {
569 * now check the dn of each search result
572 for ( m = msg->lm_chain; m != NULLMSG && rc == 0 ; m = m->lm_chain ) {
573 if ( m->lm_msgtype != LDAP_RES_SEARCH_ENTRY ) {
576 ber = *m->lm_ber; /* struct copy */
577 if ( ber_scanf( &ber, "{a", &s ) != LBER_ERROR ) {
578 rc = ( strcasecmp( dn, s ) == 0 ) ? 1 : 0;
588 msg_size( LDAPMessage *msg )
594 for ( m = msg; m != NULLMSG; m = m->lm_chain ) {
595 size += ( sizeof( LDAPMessage ) + m->lm_ber->ber_end -
596 m->lm_ber->ber_buf );
603 #define THRESHOLD_FACTOR 3 / 4
604 #define SIZE_FACTOR 2 / 3
607 check_cache_memused( LDAPCache *lc )
610 * this routine is called to check if the cache is too big (lc_maxmem >
611 * minimum cache size and lc_memused > lc_maxmem). If too big, it reduces
612 * the cache size to < SIZE_FACTOR * lc_maxmem. The algorithm is as follows:
613 * remove_threshold = lc_timeout seconds;
615 * remove everything older than remove_threshold seconds;
616 * remove_threshold = remove_threshold * THRESHOLD_FACTOR;
617 * } while ( cache size is > SIZE_FACTOR * lc_maxmem )
620 unsigned long remove_threshold, validtime;
621 LDAPMessage *m, *prev, *next;
623 Debug( LDAP_DEBUG_TRACE, "check_cache_memused: %ld bytes in use (%ld max)\n",
624 lc->lc_memused, lc->lc_maxmem, 0 );
626 if ( (unsigned) lc->lc_maxmem <= sizeof( LDAPCache )
627 || lc->lc_memused <= lc->lc_maxmem * SIZE_FACTOR ) {
631 remove_threshold = lc->lc_timeout;
632 while ( lc->lc_memused > lc->lc_maxmem * SIZE_FACTOR ) {
633 validtime = (long)time( NULL ) - remove_threshold;
634 for ( i = 0; i < LDAP_CACHE_BUCKETS; ++i ) {
636 for ( m = lc->lc_buckets[ i ]; m != NULLMSG;
639 if ( m->lm_time < validtime ) {
640 if ( prev == NULLMSG ) {
641 lc->lc_buckets[ i ] = next;
643 prev->lm_next = next;
645 lc->lc_memused -= msg_size( m );
646 Debug( LDAP_DEBUG_TRACE,
655 remove_threshold *= THRESHOLD_FACTOR;
658 Debug( LDAP_DEBUG_TRACE, "ccm: reduced usage to %ld bytes\n",
659 lc->lc_memused, 0, 0 );
662 #endif /* !NO_CACHE */