1 /* $NetBSD: dict_cache.c,v 1.4 2023/12/23 20:30:46 christos Exp $ */
2
3 /*++
4 /* NAME
5 /* dict_cache 3
6 /* SUMMARY
7 /* External cache manager
8 /* SYNOPSIS
9 /* #include <dict_cache.h>
10 /*
11 /* DICT_CACHE *dict_cache_open(dbname, open_flags, dict_flags)
12 /* const char *dbname;
13 /* int open_flags;
14 /* int dict_flags;
15 /*
16 /* void dict_cache_close(cache)
17 /* DICT_CACHE *cache;
18 /*
19 /* const char *dict_cache_lookup(cache, cache_key)
20 /* DICT_CACHE *cache;
21 /* const char *cache_key;
22 /*
23 /* int dict_cache_update(cache, cache_key, cache_val)
24 /* DICT_CACHE *cache;
25 /* const char *cache_key;
26 /* const char *cache_val;
27 /*
28 /* int dict_cache_delete(cache, cache_key)
29 /* DICT_CACHE *cache;
30 /* const char *cache_key;
31 /*
32 /* int dict_cache_sequence(cache, first_next, cache_key, cache_val)
33 /* DICT_CACHE *cache;
34 /* int first_next;
35 /* const char **cache_key;
36 /* const char **cache_val;
37 /* AUXILIARY FUNCTIONS
38 /* void dict_cache_control(cache, name, value, ...)
39 /* DICT_CACHE *cache;
40 /* int name;
41 /*
42 /* typedef int (*DICT_CACHE_VALIDATOR_FN) (const char *cache_key,
43 /* const char *cache_val, void *context);
44 /*
45 /* const char *dict_cache_name(cache)
46 /* DICT_CACHE *cache;
47 /* DESCRIPTION
48 /* This module maintains external cache files with support
49 /* for expiration. The underlying table must implement the
50 /* "lookup", "update", "delete" and "sequence" operations.
51 /*
52 /* Although this API is similar to the one documented in
53 /* dict_open(3), there are subtle differences in the interaction
54 /* between the iterators that access all cache elements, and
55 /* other operations that access individual cache elements.
56 /*
57 /* In particular, when a "sequence" or "cleanup" operation is
58 /* in progress the cache intercepts requests to delete the
59 /* "current" entry, as this would cause some databases to
60 /* mis-behave. Instead, the cache implements a "delete behind"
61 /* strategy, and deletes such an entry after the "sequence"
62 /* or "cleanup" operation moves on to the next cache element.
63 /* The "delete behind" strategy also affects the cache lookup
64 /* and update operations as detailed below.
65 /*
66 /* dict_cache_open() is a wrapper around the dict_open()
67 /* function. It opens the specified cache and returns a handle
68 /* that must be used for subsequent access. This function does
69 /* not return in case of error.
70 /*
71 /* dict_cache_close() closes the specified cache and releases
72 /* memory that was allocated by dict_cache_open(), and terminates
73 /* any thread that was started with dict_cache_control().
74 /*
75 /* dict_cache_lookup() looks up the specified cache entry.
76 /* The result value is a null pointer when the cache entry was
77 /* not found, or when the entry is scheduled for "delete
78 /* behind".
79 /*
80 /* dict_cache_update() updates the specified cache entry. If
81 /* the entry is scheduled for "delete behind", the delete
82 /* operation is canceled (because of this, the cache must be
83 /* opened with DICT_FLAG_DUP_REPLACE). This function does not
84 /* return in case of error.
85 /*
86 /* dict_cache_delete() removes the specified cache entry. If
87 /* this is the "current" entry of a "sequence" operation, the
88 /* entry is scheduled for "delete behind". The result value
89 /* is zero when the entry was found.
90 /*
91 /* dict_cache_sequence() iterates over the specified cache and
92 /* returns each entry in an implementation-defined order. The
93 /* result value is zero when a cache entry was found.
94 /*
95 /* Important: programs must not use both dict_cache_sequence()
96 /* and the built-in cache cleanup feature.
97 /*
98 /* dict_cache_control() provides control over the built-in
99 /* cache cleanup feature and logging. The arguments are a list
100 /* of macros with zero or more arguments, terminated with
101 /* CA_DICT_CACHE_CTL_END which has none. The following lists
102 /* the macros and corresponding argument types.
103 /* .IP "CA_DICT_CACHE_CTL_FLAGS(int flags)"
104 /* The arguments to this command are the bit-wise OR of zero
105 /* or more of the following:
106 /* .RS
107 /* .IP CA_DICT_CACHE_CTL_FLAG_VERBOSE
108 /* Enable verbose logging of cache activity.
109 /* .IP CA_DICT_CACHE_CTL_FLAG_EXP_SUMMARY
110 /* Log cache statistics after each cache cleanup run.
111 /* .RE
112 /* .IP "CA_DICT_CACHE_CTL_INTERVAL(int interval)"
113 /* The interval between cache cleanup runs. Specify a null
114 /* validator or interval to stop cache cleanup and log cache
115 /* statistics if a cleanup run was in progress.
116 /* .IP "CA_DICT_CACHE_CTL_VALIDATOR(DICT_CACHE_VALIDATOR_FN validator)"
117 /* An application call-back routine that returns non-zero when
118 /* a cache entry should be kept. The call-back function should
119 /* not make changes to the cache. Specify a null validator or
120 /* interval to stop cache cleanup.
121 /* .IP "CA_DICT_CACHE_CTL_CONTEXT(void *context)"
122 /* Application context that is passed to the validator function.
123 /* .RE
124 /* .PP
125 /* dict_cache_name() returns the name of the specified cache.
126 /*
127 /* Arguments:
128 /* .IP "dbname, open_flags, dict_flags"
129 /* These are passed unchanged to dict_open(). The cache must
130 /* be opened with DICT_FLAG_DUP_REPLACE.
131 /* .IP cache
132 /* Cache handle created with dict_cache_open().
133 /* .IP cache_key
134 /* Cache lookup key.
135 /* .IP cache_val
136 /* Information that is stored under a cache lookup key.
137 /* .IP first_next
138 /* One of DICT_SEQ_FUN_FIRST (first cache element) or
139 /* DICT_SEQ_FUN_NEXT (next cache element).
140 /* .sp
141 /* Note: there is no "stop" request. To ensure that the "delete
142 /* behind" strategy does not interfere with database access,
143 /* allow dict_cache_sequence() to run to completion.
144 /* .IP table
145 /* A bare dictionary handle.
146 /* DIAGNOSTICS
147 /* When a request is satisfied, the lookup routine returns
148 /* non-null, and the update, delete and sequence routines
149 /* return zero. The cache->error value is zero when a request
150 /* could not be satisfied because an item did not exist (delete,
151 /* sequence) or if it could not be updated. The cache->error
152 /* value is non-zero only when a request could not be satisfied,
153 /* and the cause was a database error.
154 /*
155 /* Cache access errors are logged with a warning message. To
156 /* avoid spamming the log, each type of operation logs no more
157 /* than one cache access error per second, per cache. Specify
158 /* the DICT_CACHE_FLAG_VERBOSE flag (see above) to log all
159 /* warnings.
160 /* BUGS
161 /* There should be a way to suspend automatic program suicide
162 /* until a cache cleanup run is completed. Some entries may
163 /* never be removed when the process max_idle time is less
164 /* than the time needed to make a full pass over the cache.
165 /*
166 /* The delete-behind strategy assumes that all updates are
167 /* made by a single process. Otherwise, delete-behind may
168 /* remove an entry that was updated after it was scheduled for
169 /* deletion.
170 /* LICENSE
171 /* .ad
172 /* .fi
173 /* The Secure Mailer license must be distributed with this software.
174 /* HISTORY
175 /* .ad
176 /* .fi
177 /* A predecessor of this code was written first for the Postfix
178 /* tlsmgr(8) daemon.
179 /* AUTHOR(S)
180 /* Wietse Venema
181 /* IBM T.J. Watson Research
182 /* P.O. Box 704
183 /* Yorktown Heights, NY 10598, USA
184 /*--*/
185
186 /* System library. */
187
188 #include <sys_defs.h>
189 #include <string.h>
190 #include <stdlib.h>
191
192 /* Utility library. */
193
194 #include <msg.h>
195 #include <dict.h>
196 #include <mymalloc.h>
197 #include <events.h>
198 #include <dict_cache.h>
199
200 /* Application-specific. */
201
202 /*
203 * XXX Deleting entries while enumerating a map can he tricky. Some map
204 * types have a concept of cursor and support a "delete the current element"
205 * operation. Some map types without cursors don't behave well when the
206 * current first/next entry is deleted (example: with Berkeley DB < 2, the
207 * "next" operation produces garbage). To avoid trouble, we delete an entry
208 * after advancing the current first/next position beyond it; we use the
209 * same strategy with application requests to delete the current entry.
210 */
211
212 /*
213 * Opaque data structure. Use dict_cache_name() to access the name of the
214 * underlying database.
215 */
216 struct DICT_CACHE {
217 char *name; /* full name including proxy: */
218 int cache_flags; /* see below */
219 int user_flags; /* logging */
220 DICT *db; /* database handle */
221 int error; /* last operation only */
222
223 /* Delete-behind support. */
224 char *saved_curr_key; /* "current" cache lookup key */
225 char *saved_curr_val; /* "current" cache lookup result */
226
227 /* Cleanup support. */
228 int exp_interval; /* time between cleanup runs */
229 DICT_CACHE_VALIDATOR_FN exp_validator; /* expiration call-back */
230 void *exp_context; /* call-back context */
231 int retained; /* entries retained in cleanup run */
232 int dropped; /* entries removed in cleanup run */
233
234 /* Rate-limited logging support. */
235 int log_delay;
236 time_t upd_log_stamp; /* last update warning */
237 time_t get_log_stamp; /* last lookup warning */
238 time_t del_log_stamp; /* last delete warning */
239 time_t seq_log_stamp; /* last sequence warning */
240 };
241
242 #define DC_FLAG_DEL_SAVED_CURRENT_KEY (1<<0) /* delete-behind is scheduled */
243
244 /*
245 * Don't log cache access errors more than once per second.
246 */
247 #define DC_DEF_LOG_DELAY 1
248
249 /*
250 * Macros to make obscure code more readable.
251 */
252 #define DC_SCHEDULE_FOR_DELETE_BEHIND(cp) \
253 ((cp)->cache_flags |= DC_FLAG_DEL_SAVED_CURRENT_KEY)
254
255 #define DC_MATCH_SAVED_CURRENT_KEY(cp, cache_key) \
256 ((cp)->saved_curr_key && strcmp((cp)->saved_curr_key, (cache_key)) == 0)
257
258 #define DC_IS_SCHEDULED_FOR_DELETE_BEHIND(cp) \
259 (/* NOT: (cp)->saved_curr_key && */ \
260 ((cp)->cache_flags & DC_FLAG_DEL_SAVED_CURRENT_KEY) != 0)
261
262 #define DC_CANCEL_DELETE_BEHIND(cp) \
263 ((cp)->cache_flags &= ~DC_FLAG_DEL_SAVED_CURRENT_KEY)
264
265 /*
266 * Special key to store the time of the last cache cleanup run completion.
267 */
268 #define DC_LAST_CACHE_CLEANUP_COMPLETED "_LAST_CACHE_CLEANUP_COMPLETED_"
269
270 /* dict_cache_lookup - load entry from cache */
271
dict_cache_lookup(DICT_CACHE * cp,const char * cache_key)272 const char *dict_cache_lookup(DICT_CACHE *cp, const char *cache_key)
273 {
274 const char *myname = "dict_cache_lookup";
275 const char *cache_val;
276 DICT *db = cp->db;
277
278 /*
279 * Search for the cache entry. Don't return an entry that is scheduled
280 * for delete-behind.
281 */
282 if (DC_IS_SCHEDULED_FOR_DELETE_BEHIND(cp)
283 && DC_MATCH_SAVED_CURRENT_KEY(cp, cache_key)) {
284 if (cp->user_flags & DICT_CACHE_FLAG_VERBOSE)
285 msg_info("%s: key=%s (pretend not found - scheduled for deletion)",
286 myname, cache_key);
287 DICT_ERR_VAL_RETURN(cp, DICT_ERR_NONE, (char *) 0);
288 } else {
289 cache_val = dict_get(db, cache_key);
290 if (cache_val == 0 && db->error != 0)
291 msg_rate_delay(&cp->get_log_stamp, cp->log_delay, msg_warn,
292 "%s: cache lookup for '%s' failed due to error",
293 cp->name, cache_key);
294 if (cp->user_flags & DICT_CACHE_FLAG_VERBOSE)
295 msg_info("%s: key=%s value=%s", myname, cache_key,
296 cache_val ? cache_val : db->error ?
297 "error" : "(not found)");
298 DICT_ERR_VAL_RETURN(cp, db->error, cache_val);
299 }
300 }
301
302 /* dict_cache_update - save entry to cache */
303
dict_cache_update(DICT_CACHE * cp,const char * cache_key,const char * cache_val)304 int dict_cache_update(DICT_CACHE *cp, const char *cache_key,
305 const char *cache_val)
306 {
307 const char *myname = "dict_cache_update";
308 DICT *db = cp->db;
309 int put_res;
310
311 /*
312 * Store the cache entry and cancel the delete-behind operation.
313 */
314 if (DC_IS_SCHEDULED_FOR_DELETE_BEHIND(cp)
315 && DC_MATCH_SAVED_CURRENT_KEY(cp, cache_key)) {
316 if (cp->user_flags & DICT_CACHE_FLAG_VERBOSE)
317 msg_info("%s: cancel delete-behind for key=%s", myname, cache_key);
318 DC_CANCEL_DELETE_BEHIND(cp);
319 }
320 if (cp->user_flags & DICT_CACHE_FLAG_VERBOSE)
321 msg_info("%s: key=%s value=%s", myname, cache_key, cache_val);
322 put_res = dict_put(db, cache_key, cache_val);
323 if (put_res != 0)
324 msg_rate_delay(&cp->upd_log_stamp, cp->log_delay, msg_warn,
325 "%s: could not update entry for %s", cp->name, cache_key);
326 DICT_ERR_VAL_RETURN(cp, db->error, put_res);
327 }
328
329 /* dict_cache_delete - delete entry from cache */
330
dict_cache_delete(DICT_CACHE * cp,const char * cache_key)331 int dict_cache_delete(DICT_CACHE *cp, const char *cache_key)
332 {
333 const char *myname = "dict_cache_delete";
334 int del_res;
335 DICT *db = cp->db;
336
337 /*
338 * Delete the entry, unless we would delete the current first/next entry.
339 * In that case, schedule the "current" entry for delete-behind to avoid
340 * mis-behavior by some databases.
341 */
342 if (DC_MATCH_SAVED_CURRENT_KEY(cp, cache_key)) {
343 DC_SCHEDULE_FOR_DELETE_BEHIND(cp);
344 if (cp->user_flags & DICT_CACHE_FLAG_VERBOSE)
345 msg_info("%s: key=%s (current entry - schedule for delete-behind)",
346 myname, cache_key);
347 DICT_ERR_VAL_RETURN(cp, DICT_ERR_NONE, DICT_STAT_SUCCESS);
348 } else {
349 del_res = dict_del(db, cache_key);
350 if (del_res != 0)
351 msg_rate_delay(&cp->del_log_stamp, cp->log_delay, msg_warn,
352 "%s: could not delete entry for %s", cp->name, cache_key);
353 if (cp->user_flags & DICT_CACHE_FLAG_VERBOSE)
354 msg_info("%s: key=%s (%s)", myname, cache_key,
355 del_res == 0 ? "found" :
356 db->error ? "error" : "not found");
357 DICT_ERR_VAL_RETURN(cp, db->error, del_res);
358 }
359 }
360
361 /* dict_cache_sequence - look up the first/next cache entry */
362
dict_cache_sequence(DICT_CACHE * cp,int first_next,const char ** cache_key,const char ** cache_val)363 int dict_cache_sequence(DICT_CACHE *cp, int first_next,
364 const char **cache_key,
365 const char **cache_val)
366 {
367 const char *myname = "dict_cache_sequence";
368 int seq_res;
369 const char *raw_cache_key;
370 const char *raw_cache_val;
371 char *previous_curr_key;
372 char *previous_curr_val;
373 DICT *db = cp->db;
374
375 /*
376 * Find the first or next database entry. Hide the record with the cache
377 * cleanup completion time stamp.
378 */
379 seq_res = dict_seq(db, first_next, &raw_cache_key, &raw_cache_val);
380 if (seq_res == 0
381 && strcmp(raw_cache_key, DC_LAST_CACHE_CLEANUP_COMPLETED) == 0)
382 seq_res =
383 dict_seq(db, DICT_SEQ_FUN_NEXT, &raw_cache_key, &raw_cache_val);
384 if (cp->user_flags & DICT_CACHE_FLAG_VERBOSE)
385 msg_info("%s: key=%s value=%s", myname,
386 seq_res == 0 ? raw_cache_key : db->error ?
387 "(error)" : "(not found)",
388 seq_res == 0 ? raw_cache_val : db->error ?
389 "(error)" : "(not found)");
390 if (db->error)
391 msg_rate_delay(&cp->seq_log_stamp, cp->log_delay, msg_warn,
392 "%s: sequence error", cp->name);
393
394 /*
395 * Save the current cache_key and cache_val before they are clobbered by
396 * our own delete operation below. This also prevents surprises when the
397 * application accesses the database after this function returns.
398 *
399 * We also use the saved cache_key to protect the current entry against
400 * application delete requests.
401 */
402 previous_curr_key = cp->saved_curr_key;
403 previous_curr_val = cp->saved_curr_val;
404 if (seq_res == 0) {
405 cp->saved_curr_key = mystrdup(raw_cache_key);
406 cp->saved_curr_val = mystrdup(raw_cache_val);
407 } else {
408 cp->saved_curr_key = 0;
409 cp->saved_curr_val = 0;
410 }
411
412 /*
413 * Delete behind.
414 */
415 if (db->error == 0 && DC_IS_SCHEDULED_FOR_DELETE_BEHIND(cp)) {
416 DC_CANCEL_DELETE_BEHIND(cp);
417 if (cp->user_flags & DICT_CACHE_FLAG_VERBOSE)
418 msg_info("%s: delete-behind key=%s value=%s",
419 myname, previous_curr_key, previous_curr_val);
420 if (dict_del(db, previous_curr_key) != 0)
421 msg_rate_delay(&cp->del_log_stamp, cp->log_delay, msg_warn,
422 "%s: could not delete entry for %s",
423 cp->name, previous_curr_key);
424 }
425
426 /*
427 * Clean up previous iteration key and value.
428 */
429 if (previous_curr_key)
430 myfree(previous_curr_key);
431 if (previous_curr_val)
432 myfree(previous_curr_val);
433
434 /*
435 * Return the result.
436 */
437 *cache_key = (cp)->saved_curr_key;
438 *cache_val = (cp)->saved_curr_val;
439 DICT_ERR_VAL_RETURN(cp, db->error, seq_res);
440 }
441
442 /* dict_cache_delete_behind_reset - reset "delete behind" state */
443
dict_cache_delete_behind_reset(DICT_CACHE * cp)444 static void dict_cache_delete_behind_reset(DICT_CACHE *cp)
445 {
446 #define FREE_AND_WIPE(s) do { if (s) { myfree(s); (s) = 0; } } while (0)
447
448 DC_CANCEL_DELETE_BEHIND(cp);
449 FREE_AND_WIPE(cp->saved_curr_key);
450 FREE_AND_WIPE(cp->saved_curr_val);
451 }
452
453 /* dict_cache_clean_stat_log_reset - log and reset cache cleanup statistics */
454
dict_cache_clean_stat_log_reset(DICT_CACHE * cp,const char * full_partial)455 static void dict_cache_clean_stat_log_reset(DICT_CACHE *cp,
456 const char *full_partial)
457 {
458 if (cp->user_flags & DICT_CACHE_FLAG_STATISTICS)
459 msg_info("cache %s %s cleanup: retained=%d dropped=%d entries",
460 cp->name, full_partial, cp->retained, cp->dropped);
461 cp->retained = cp->dropped = 0;
462 }
463
464 /* dict_cache_clean_event - examine one cache entry */
465
dict_cache_clean_event(int unused_event,void * cache_context)466 static void dict_cache_clean_event(int unused_event, void *cache_context)
467 {
468 const char *myname = "dict_cache_clean_event";
469 DICT_CACHE *cp = (DICT_CACHE *) cache_context;
470 const char *cache_key;
471 const char *cache_val;
472 int next_interval;
473 VSTRING *stamp_buf;
474 int first_next;
475
476 /*
477 * We interleave cache cleanup with other processing, so that the
478 * application's service remains available, with perhaps increased
479 * latency.
480 */
481
482 /*
483 * Start a new cache cleanup run.
484 */
485 if (cp->saved_curr_key == 0) {
486 cp->retained = cp->dropped = 0;
487 first_next = DICT_SEQ_FUN_FIRST;
488 if (cp->user_flags & DICT_CACHE_FLAG_VERBOSE)
489 msg_info("%s: start %s cache cleanup", myname, cp->name);
490 }
491
492 /*
493 * Continue a cache cleanup run in progress.
494 */
495 else {
496 first_next = DICT_SEQ_FUN_NEXT;
497 }
498
499 /*
500 * Examine one cache entry.
501 */
502 if (dict_cache_sequence(cp, first_next, &cache_key, &cache_val) == 0) {
503 if (cp->exp_validator(cache_key, cache_val, cp->exp_context) == 0) {
504 DC_SCHEDULE_FOR_DELETE_BEHIND(cp);
505 cp->dropped++;
506 if (cp->user_flags & DICT_CACHE_FLAG_VERBOSE)
507 msg_info("%s: drop %s cache entry for %s",
508 myname, cp->name, cache_key);
509 } else {
510 cp->retained++;
511 if (cp->user_flags & DICT_CACHE_FLAG_VERBOSE)
512 msg_info("%s: keep %s cache entry for %s",
513 myname, cp->name, cache_key);
514 }
515 next_interval = 0;
516 }
517
518 /*
519 * Cache cleanup completed. Report vital statistics.
520 */
521 else if (cp->error != 0) {
522 msg_warn("%s: cache cleanup scan terminated due to error", cp->name);
523 dict_cache_clean_stat_log_reset(cp, "partial");
524 next_interval = cp->exp_interval;
525 } else {
526 if (cp->user_flags & DICT_CACHE_FLAG_VERBOSE)
527 msg_info("%s: done %s cache cleanup scan", myname, cp->name);
528 dict_cache_clean_stat_log_reset(cp, "full");
529 stamp_buf = vstring_alloc(100);
530 vstring_sprintf(stamp_buf, "%ld", (long) event_time());
531 dict_put(cp->db, DC_LAST_CACHE_CLEANUP_COMPLETED,
532 vstring_str(stamp_buf));
533 vstring_free(stamp_buf);
534 next_interval = cp->exp_interval;
535 }
536 event_request_timer(dict_cache_clean_event, cache_context, next_interval);
537 }
538
539 /* dict_cache_control - schedule or stop the cache cleanup thread */
540
dict_cache_control(DICT_CACHE * cp,...)541 void dict_cache_control(DICT_CACHE *cp,...)
542 {
543 const char *myname = "dict_cache_control";
544 const char *last_done;
545 time_t next_interval;
546 int cache_cleanup_is_active = (cp->exp_validator && cp->exp_interval);
547 va_list ap;
548 int name;
549
550 /*
551 * Update the control settings.
552 */
553 va_start(ap, cp);
554 while ((name = va_arg(ap, int)) > 0) {
555 switch (name) {
556 case DICT_CACHE_CTL_END:
557 break;
558 case DICT_CACHE_CTL_FLAGS:
559 cp->user_flags = va_arg(ap, int);
560 cp->log_delay = (cp->user_flags & DICT_CACHE_FLAG_VERBOSE) ?
561 0 : DC_DEF_LOG_DELAY;
562 break;
563 case DICT_CACHE_CTL_INTERVAL:
564 cp->exp_interval = va_arg(ap, int);
565 if (cp->exp_interval < 0)
566 msg_panic("%s: bad %s cache cleanup interval %d",
567 myname, cp->name, cp->exp_interval);
568 break;
569 case DICT_CACHE_CTL_VALIDATOR:
570 cp->exp_validator = va_arg(ap, DICT_CACHE_VALIDATOR_FN);
571 break;
572 case DICT_CACHE_CTL_CONTEXT:
573 cp->exp_context = va_arg(ap, void *);
574 break;
575 default:
576 msg_panic("%s: bad command: %d", myname, name);
577 }
578 }
579 va_end(ap);
580
581 /*
582 * Schedule the cache cleanup thread.
583 */
584 if (cp->exp_interval && cp->exp_validator) {
585
586 /*
587 * Sanity checks.
588 */
589 if (cache_cleanup_is_active)
590 msg_panic("%s: %s cache cleanup is already scheduled",
591 myname, cp->name);
592
593 /*
594 * The next start time depends on the last completion time.
595 */
596 #define NEXT_START(last, delta) ((delta) + (unsigned long) atol(last))
597 #define NOW (time((time_t *) 0)) /* NOT: event_time() */
598
599 if ((last_done = dict_get(cp->db, DC_LAST_CACHE_CLEANUP_COMPLETED)) == 0
600 || (next_interval = (NEXT_START(last_done, cp->exp_interval) - NOW)) < 0)
601 next_interval = 0;
602 if (next_interval > cp->exp_interval)
603 next_interval = cp->exp_interval;
604 if ((cp->user_flags & DICT_CACHE_FLAG_VERBOSE) && next_interval > 0)
605 msg_info("%s cache cleanup will start after %ds",
606 cp->name, (int) next_interval);
607 event_request_timer(dict_cache_clean_event, (void *) cp,
608 (int) next_interval);
609 }
610
611 /*
612 * Cancel the cache cleanup thread.
613 */
614 else if (cache_cleanup_is_active) {
615 if (cp->retained || cp->dropped)
616 dict_cache_clean_stat_log_reset(cp, "partial");
617 dict_cache_delete_behind_reset(cp);
618 event_cancel_timer(dict_cache_clean_event, (void *) cp);
619 }
620 }
621
622 /* dict_cache_open - open cache file */
623
dict_cache_open(const char * dbname,int open_flags,int dict_flags)624 DICT_CACHE *dict_cache_open(const char *dbname, int open_flags, int dict_flags)
625 {
626 DICT_CACHE *cp;
627 DICT *dict;
628
629 /*
630 * Open the database as requested. Don't attempt to second-guess the
631 * application.
632 */
633 dict = dict_open(dbname, open_flags, dict_flags);
634
635 /*
636 * Create the DICT_CACHE object.
637 */
638 cp = (DICT_CACHE *) mymalloc(sizeof(*cp));
639 cp->name = mystrdup(dbname);
640 cp->cache_flags = 0;
641 cp->user_flags = 0;
642 cp->db = dict;
643 cp->saved_curr_key = 0;
644 cp->saved_curr_val = 0;
645 cp->exp_interval = 0;
646 cp->exp_validator = 0;
647 cp->exp_context = 0;
648 cp->retained = 0;
649 cp->dropped = 0;
650 cp->log_delay = DC_DEF_LOG_DELAY;
651 cp->upd_log_stamp = cp->get_log_stamp =
652 cp->del_log_stamp = cp->seq_log_stamp = 0;
653
654 return (cp);
655 }
656
657 /* dict_cache_close - close cache file */
658
dict_cache_close(DICT_CACHE * cp)659 void dict_cache_close(DICT_CACHE *cp)
660 {
661
662 /*
663 * Cancel the cache cleanup thread. This also logs (and resets)
664 * statistics for a scan that is in progress.
665 */
666 dict_cache_control(cp, DICT_CACHE_CTL_INTERVAL, 0, DICT_CACHE_CTL_END);
667
668 /*
669 * Destroy the DICT_CACHE object.
670 */
671 myfree(cp->name);
672 dict_close(cp->db);
673 if (cp->saved_curr_key)
674 myfree(cp->saved_curr_key);
675 if (cp->saved_curr_val)
676 myfree(cp->saved_curr_val);
677 myfree((void *) cp);
678 }
679
680 /* dict_cache_name - get the cache name */
681
dict_cache_name(DICT_CACHE * cp)682 const char *dict_cache_name(DICT_CACHE *cp)
683 {
684
685 /*
686 * This is used for verbose logging or warning messages, so the cost of
687 * call is only made where needed (well sort off - code that does not
688 * execute still presents overhead for the processor pipeline, processor
689 * cache, etc).
690 */
691 return (cp->name);
692 }
693
694 /*
695 * Test driver with support for interleaved access. First, enter a number of
696 * requests to look up, update or delete a sequence of cache entries, then
697 * interleave those sequences with the "run" command.
698 */
699 #ifdef TEST
700 #include <msg_vstream.h>
701 #include <vstring_vstream.h>
702 #include <argv.h>
703 #include <stringops.h>
704
705 #define DELIMS " "
706 #define USAGE "\n\tTo manage settings:" \
707 "\n\tverbose <level> (verbosity level)" \
708 "\n\telapsed <level> (0=don't show elapsed time)" \
709 "\n\tlmdb_map_size <limit> (initial LMDB size limit)" \
710 "\n\tcache <type>:<name> (switch to named database)" \
711 "\n\tstatus (show map size, cache, pending requests)" \
712 "\n\n\tTo manage pending requests:" \
713 "\n\treset (discard pending requests)" \
714 "\n\trun (execute pending requests in interleaved order)" \
715 "\n\n\tTo add a pending request:" \
716 "\n\tquery <key-suffix> <count> (negative to reverse order)" \
717 "\n\tupdate <key-suffix> <count> (negative to reverse order)" \
718 "\n\tdelete <key-suffix> <count> (negative to reverse order)" \
719 "\n\tpurge <key-suffix>" \
720 "\n\tcount <key-suffix>"
721
722 /*
723 * For realism, open the cache with the same flags as postscreen(8) and
724 * verify(8).
725 */
726 #define DICT_CACHE_OPEN_FLAGS (DICT_FLAG_DUP_REPLACE | DICT_FLAG_SYNC_UPDATE | \
727 DICT_FLAG_OPEN_LOCK)
728
729 /*
730 * Storage for one request to access a sequence of cache entries.
731 */
732 typedef struct DICT_CACHE_SREQ {
733 int flags; /* per-request: reverse, purge */
734 char *cmd; /* command for status report */
735 void (*action) (struct DICT_CACHE_SREQ *, DICT_CACHE *, VSTRING *);
736 char *suffix; /* key suffix */
737 int done; /* progress indicator */
738 int todo; /* number of entries to process */
739 int first_next; /* first/next */
740 } DICT_CACHE_SREQ;
741
742 #define DICT_CACHE_SREQ_FLAG_PURGE (1<<1) /* purge instead of count */
743 #define DICT_CACHE_SREQ_FLAG_REVERSE (1<<2) /* reverse instead of forward */
744
745 #define DICT_CACHE_SREQ_LIMIT 10
746
747 /*
748 * All test requests combined.
749 */
750 typedef struct DICT_CACHE_TEST {
751 int flags; /* exclusion flags */
752 int size; /* allocated slots */
753 int used; /* used slots */
754 DICT_CACHE_SREQ job_list[1]; /* actually, a bunch */
755 } DICT_CACHE_TEST;
756
757 #define DICT_CACHE_TEST_FLAG_ITER (1<<0) /* count or purge */
758
759 #define STR(x) vstring_str(x)
760
761 int show_elapsed = 1; /* show elapsed time */
762
763 #ifdef HAS_LMDB
764 extern size_t dict_lmdb_map_size; /* LMDB-specific */
765
766 #endif
767
768 /* usage - command-line usage message */
769
usage(const char * progname)770 static NORETURN usage(const char *progname)
771 {
772 msg_fatal("usage: %s (no argument)", progname);
773 }
774
775 /* make_tagged_key - make tagged search key */
776
make_tagged_key(VSTRING * bp,DICT_CACHE_SREQ * cp)777 static void make_tagged_key(VSTRING *bp, DICT_CACHE_SREQ *cp)
778 {
779 if (cp->done < 0)
780 msg_panic("make_tagged_key: bad done count: %d", cp->done);
781 if (cp->todo < 1)
782 msg_panic("make_tagged_key: bad todo count: %d", cp->todo);
783 vstring_sprintf(bp, "%d-%s",
784 (cp->flags & DICT_CACHE_SREQ_FLAG_REVERSE) ?
785 cp->todo - cp->done - 1 : cp->done, cp->suffix);
786 }
787
788 /* create_requests - create request list */
789
create_requests(int count)790 static DICT_CACHE_TEST *create_requests(int count)
791 {
792 DICT_CACHE_TEST *tp;
793 DICT_CACHE_SREQ *cp;
794
795 tp = (DICT_CACHE_TEST *) mymalloc(sizeof(DICT_CACHE_TEST) +
796 (count - 1) *sizeof(DICT_CACHE_SREQ));
797 tp->flags = 0;
798 tp->size = count;
799 tp->used = 0;
800 for (cp = tp->job_list; cp < tp->job_list + count; cp++) {
801 cp->flags = 0;
802 cp->cmd = 0;
803 cp->action = 0;
804 cp->suffix = 0;
805 cp->todo = 0;
806 cp->first_next = DICT_SEQ_FUN_FIRST;
807 }
808 return (tp);
809 }
810
811 /* reset_requests - reset request list */
812
reset_requests(DICT_CACHE_TEST * tp)813 static void reset_requests(DICT_CACHE_TEST *tp)
814 {
815 DICT_CACHE_SREQ *cp;
816
817 tp->flags = 0;
818 tp->used = 0;
819 for (cp = tp->job_list; cp < tp->job_list + tp->size; cp++) {
820 cp->flags = 0;
821 if (cp->cmd) {
822 myfree(cp->cmd);
823 cp->cmd = 0;
824 }
825 cp->action = 0;
826 if (cp->suffix) {
827 myfree(cp->suffix);
828 cp->suffix = 0;
829 }
830 cp->todo = 0;
831 cp->first_next = DICT_SEQ_FUN_FIRST;
832 }
833 }
834
835 /* free_requests - destroy request list */
836
free_requests(DICT_CACHE_TEST * tp)837 static void free_requests(DICT_CACHE_TEST *tp)
838 {
839 reset_requests(tp);
840 myfree((void *) tp);
841 }
842
843 /* run_requests - execute pending requests in interleaved order */
844
run_requests(DICT_CACHE_TEST * tp,DICT_CACHE * dp,VSTRING * bp)845 static void run_requests(DICT_CACHE_TEST *tp, DICT_CACHE *dp, VSTRING *bp)
846 {
847 DICT_CACHE_SREQ *cp;
848 int todo;
849 struct timeval start;
850 struct timeval finish;
851 struct timeval elapsed;
852
853 if (dp == 0) {
854 msg_warn("no cache");
855 return;
856 }
857 GETTIMEOFDAY(&start);
858 do {
859 todo = 0;
860 for (cp = tp->job_list; cp < tp->job_list + tp->used; cp++) {
861 if (cp->done < cp->todo) {
862 todo = 1;
863 cp->action(cp, dp, bp);
864 }
865 }
866 } while (todo);
867 GETTIMEOFDAY(&finish);
868 timersub(&finish, &start, &elapsed);
869 if (show_elapsed)
870 vstream_printf("Elapsed: %g\n",
871 elapsed.tv_sec + elapsed.tv_usec / 1000000.0);
872
873 reset_requests(tp);
874 }
875
876 /* show_status - show settings and pending requests */
877
show_status(DICT_CACHE_TEST * tp,DICT_CACHE * dp)878 static void show_status(DICT_CACHE_TEST *tp, DICT_CACHE *dp)
879 {
880 DICT_CACHE_SREQ *cp;
881
882 #ifdef HAS_LMDB
883 vstream_printf("lmdb_map_size\t%ld\n", (long) dict_lmdb_map_size);
884 #endif
885 vstream_printf("cache\t%s\n", dp ? dp->name : "(none)");
886
887 if (tp->used == 0)
888 vstream_printf("No pending requests\n");
889 else
890 vstream_printf("%s\t%s\t%s\t%s\t%s\t%s\n",
891 "cmd", "dir", "suffix", "count", "done", "first/next");
892
893 for (cp = tp->job_list; cp < tp->job_list + tp->used; cp++)
894 if (cp->todo > 0)
895 vstream_printf("%s\t%s\t%s\t%d\t%d\t%d\n",
896 cp->cmd,
897 (cp->flags & DICT_CACHE_SREQ_FLAG_REVERSE) ?
898 "reverse" : "forward",
899 cp->suffix ? cp->suffix : "(null)", cp->todo,
900 cp->done, cp->first_next);
901 }
902
903 /* query_action - lookup cache entry */
904
query_action(DICT_CACHE_SREQ * cp,DICT_CACHE * dp,VSTRING * bp)905 static void query_action(DICT_CACHE_SREQ *cp, DICT_CACHE *dp, VSTRING *bp)
906 {
907 const char *lookup;
908
909 make_tagged_key(bp, cp);
910 if ((lookup = dict_cache_lookup(dp, STR(bp))) == 0) {
911 if (dp->error)
912 msg_warn("query_action: query failed: %s: %m", STR(bp));
913 else
914 msg_warn("query_action: query failed: %s", STR(bp));
915 } else if (strcmp(STR(bp), lookup) != 0) {
916 msg_warn("lookup result \"%s\" differs from key \"%s\"",
917 lookup, STR(bp));
918 }
919 cp->done += 1;
920 }
921
922 /* update_action - update cache entry */
923
update_action(DICT_CACHE_SREQ * cp,DICT_CACHE * dp,VSTRING * bp)924 static void update_action(DICT_CACHE_SREQ *cp, DICT_CACHE *dp, VSTRING *bp)
925 {
926 make_tagged_key(bp, cp);
927 if (dict_cache_update(dp, STR(bp), STR(bp)) != 0) {
928 if (dp->error)
929 msg_warn("update_action: update failed: %s: %m", STR(bp));
930 else
931 msg_warn("update_action: update failed: %s", STR(bp));
932 }
933 cp->done += 1;
934 }
935
936 /* delete_action - delete cache entry */
937
delete_action(DICT_CACHE_SREQ * cp,DICT_CACHE * dp,VSTRING * bp)938 static void delete_action(DICT_CACHE_SREQ *cp, DICT_CACHE *dp, VSTRING *bp)
939 {
940 make_tagged_key(bp, cp);
941 if (dict_cache_delete(dp, STR(bp)) != 0) {
942 if (dp->error)
943 msg_warn("delete_action: delete failed: %s: %m", STR(bp));
944 else
945 msg_warn("delete_action: delete failed: %s", STR(bp));
946 }
947 cp->done += 1;
948 }
949
950 /* iter_action - iterate over cache and act on entries with given suffix */
951
iter_action(DICT_CACHE_SREQ * cp,DICT_CACHE * dp,VSTRING * bp)952 static void iter_action(DICT_CACHE_SREQ *cp, DICT_CACHE *dp, VSTRING *bp)
953 {
954 const char *cache_key;
955 const char *cache_val;
956 const char *what;
957 const char *suffix;
958
959 if (dict_cache_sequence(dp, cp->first_next, &cache_key, &cache_val) == 0) {
960 if (strcmp(cache_key, cache_val) != 0)
961 msg_warn("value \"%s\" differs from key \"%s\"",
962 cache_val, cache_key);
963 suffix = cache_key + strspn(cache_key, "0123456789");
964 if (suffix[0] == '-' && strcmp(suffix + 1, cp->suffix) == 0) {
965 cp->done += 1;
966 cp->todo = cp->done + 1; /* XXX */
967 if ((cp->flags & DICT_CACHE_SREQ_FLAG_PURGE)
968 && dict_cache_delete(dp, cache_key) != 0) {
969 if (dp->error)
970 msg_warn("purge_action: delete failed: %s: %m", STR(bp));
971 else
972 msg_warn("purge_action: delete failed: %s", STR(bp));
973 }
974 }
975 cp->first_next = DICT_SEQ_FUN_NEXT;
976 } else {
977 what = (cp->flags & DICT_CACHE_SREQ_FLAG_PURGE) ? "purge" : "count";
978 if (dp->error)
979 msg_warn("%s error after %d: %m", what, cp->done);
980 else
981 vstream_printf("suffix=%s %s=%d\n", cp->suffix, what, cp->done);
982 cp->todo = 0;
983 }
984 }
985
986 /*
987 * Table-driven support.
988 */
989 typedef struct DICT_CACHE_SREQ_INFO {
990 const char *name;
991 int argc;
992 void (*action) (DICT_CACHE_SREQ *, DICT_CACHE *, VSTRING *);
993 int test_flags;
994 int req_flags;
995 } DICT_CACHE_SREQ_INFO;
996
997 static DICT_CACHE_SREQ_INFO req_info[] = {
998 {"query", 3, query_action},
999 {"update", 3, update_action},
1000 {"delete", 3, delete_action},
1001 {"count", 2, iter_action, DICT_CACHE_TEST_FLAG_ITER},
1002 {"purge", 2, iter_action, DICT_CACHE_TEST_FLAG_ITER, DICT_CACHE_SREQ_FLAG_PURGE},
1003 0,
1004 };
1005
1006 /* add_request - add a request to the list */
1007
add_request(DICT_CACHE_TEST * tp,ARGV * argv)1008 static void add_request(DICT_CACHE_TEST *tp, ARGV *argv)
1009 {
1010 DICT_CACHE_SREQ_INFO *rp;
1011 DICT_CACHE_SREQ *cp;
1012 int req_flags;
1013 int count;
1014 char *cmd = argv->argv[0];
1015 char *suffix = (argv->argc > 1 ? argv->argv[1] : 0);
1016 char *todo = (argv->argc > 2 ? argv->argv[2] : "1"); /* XXX */
1017
1018 if (tp->used >= tp->size) {
1019 msg_warn("%s: request list is full", cmd);
1020 return;
1021 }
1022 for (rp = req_info; /* See below */ ; rp++) {
1023 if (rp->name == 0) {
1024 vstream_printf("usage: %s\n", USAGE);
1025 return;
1026 }
1027 if (strcmp(rp->name, argv->argv[0]) == 0
1028 && rp->argc == argv->argc)
1029 break;
1030 }
1031 req_flags = rp->req_flags;
1032 if (todo[0] == '-') {
1033 req_flags |= DICT_CACHE_SREQ_FLAG_REVERSE;
1034 todo += 1;
1035 }
1036 if (!alldig(todo) || (count = atoi(todo)) == 0) {
1037 msg_warn("%s: bad count: %s", cmd, todo);
1038 return;
1039 }
1040 if (tp->flags & rp->test_flags) {
1041 msg_warn("%s: command conflicts with other command", cmd);
1042 return;
1043 }
1044 tp->flags |= rp->test_flags;
1045 cp = tp->job_list + tp->used;
1046 cp->cmd = mystrdup(cmd);
1047 cp->action = rp->action;
1048 if (suffix)
1049 cp->suffix = mystrdup(suffix);
1050 cp->done = 0;
1051 cp->flags = req_flags;
1052 cp->todo = count;
1053 tp->used += 1;
1054 }
1055
1056 /* main - main program */
1057
main(int argc,char ** argv)1058 int main(int argc, char **argv)
1059 {
1060 DICT_CACHE_TEST *test_job;
1061 VSTRING *inbuf = vstring_alloc(100);
1062 char *bufp;
1063 ARGV *args;
1064 DICT_CACHE *cache = 0;
1065 int stdin_is_tty;
1066
1067 msg_vstream_init(argv[0], VSTREAM_ERR);
1068 if (argc != 1)
1069 usage(argv[0]);
1070
1071
1072 test_job = create_requests(DICT_CACHE_SREQ_LIMIT);
1073
1074 stdin_is_tty = isatty(0);
1075
1076 for (;;) {
1077 if (stdin_is_tty) {
1078 vstream_printf("> ");
1079 vstream_fflush(VSTREAM_OUT);
1080 }
1081 if (vstring_fgets_nonl(inbuf, VSTREAM_IN) == 0)
1082 break;
1083 bufp = vstring_str(inbuf);
1084 if (!stdin_is_tty) {
1085 vstream_printf("> %s\n", bufp);
1086 vstream_fflush(VSTREAM_OUT);
1087 }
1088 if (*bufp == '#')
1089 continue;
1090 args = argv_split(bufp, DELIMS);
1091 if (argc == 0) {
1092 vstream_printf("usage: %s\n", USAGE);
1093 vstream_fflush(VSTREAM_OUT);
1094 continue;
1095 }
1096 if (strcmp(args->argv[0], "verbose") == 0 && args->argc == 2) {
1097 msg_verbose = atoi(args->argv[1]);
1098 } else if (strcmp(args->argv[0], "elapsed") == 0 && args->argc == 2) {
1099 show_elapsed = atoi(args->argv[1]);
1100 #ifdef HAS_LMDB
1101 } else if (strcmp(args->argv[0], "lmdb_map_size") == 0 && args->argc == 2) {
1102 dict_lmdb_map_size = atol(args->argv[1]);
1103 #endif
1104 } else if (strcmp(args->argv[0], "cache") == 0 && args->argc == 2) {
1105 if (cache)
1106 dict_cache_close(cache);
1107 cache = dict_cache_open(args->argv[1], O_CREAT | O_RDWR,
1108 DICT_CACHE_OPEN_FLAGS);
1109 } else if (strcmp(args->argv[0], "reset") == 0 && args->argc == 1) {
1110 reset_requests(test_job);
1111 } else if (strcmp(args->argv[0], "run") == 0 && args->argc == 1) {
1112 run_requests(test_job, cache, inbuf);
1113 } else if (strcmp(args->argv[0], "status") == 0 && args->argc == 1) {
1114 show_status(test_job, cache);
1115 } else {
1116 add_request(test_job, args);
1117 }
1118 vstream_fflush(VSTREAM_OUT);
1119 argv_free(args);
1120 }
1121
1122 vstring_free(inbuf);
1123 free_requests(test_job);
1124 if (cache)
1125 dict_cache_close(cache);
1126 return (0);
1127 }
1128
1129 #endif
1130