ctdb-daemon: Do not allow database detach if AllowClientDBAttach=1
[Samba.git] / source3 / lib / gencache.c
blob0fb1fd8280ef52db47c72aa165161b6d57f6623f
1 /*
2 Unix SMB/CIFS implementation.
4 Generic, persistent and shared between processes cache mechanism for use
5 by various parts of the Samba code
7 Copyright (C) Rafal Szczesniak 2002
8 Copyright (C) Volker Lendecke 2009
10 This program is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 3 of the License, or
13 (at your option) any later version.
15 This program is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with this program. If not, see <http://www.gnu.org/licenses/>.
24 #include "includes.h"
25 #include "system/filesys.h"
26 #include "system/glob.h"
27 #include "util_tdb.h"
28 #include "memcache.h"
30 #undef DBGC_CLASS
31 #define DBGC_CLASS DBGC_TDB
33 #define TIMEOUT_LEN 12
34 #define CACHE_DATA_FMT "%12u/"
35 #define READ_CACHE_DATA_FMT_TEMPLATE "%%12u/%%%us"
36 #define BLOB_TYPE "DATA_BLOB"
37 #define BLOB_TYPE_LEN 9
39 static struct tdb_context *cache;
40 static struct tdb_context *cache_notrans;
41 static int cache_notrans_seqnum;
43 /**
44 * @file gencache.c
45 * @brief Generic, persistent and shared between processes cache mechanism
46 * for use by various parts of the Samba code
48 **/
51 /**
52 * Cache initialisation function. Opens cache tdb file or creates
53 * it if does not exist.
55 * @return true on successful initialisation of the cache or
56 * false on failure
57 **/
59 static bool gencache_init(void)
61 char* cache_fname = NULL;
62 int open_flags = O_RDWR|O_CREAT;
64 /* skip file open if it's already opened */
65 if (cache) return True;
67 cache_fname = cache_path("gencache.tdb");
69 DEBUG(5, ("Opening cache file at %s\n", cache_fname));
71 cache = tdb_open_log(cache_fname, 0, TDB_DEFAULT|TDB_INCOMPATIBLE_HASH, open_flags, 0644);
72 if (cache) {
73 int ret;
74 ret = tdb_check(cache, NULL, NULL);
75 if (ret != 0) {
76 tdb_close(cache);
79 * Retry with CLEAR_IF_FIRST.
81 * Warning: Converting this to dbwrap won't work
82 * directly. gencache.c does transactions on this tdb,
83 * and dbwrap forbids this for CLEAR_IF_FIRST
84 * databases. tdb does allow transactions on
85 * CLEAR_IF_FIRST databases, so lets use it here to
86 * clean up a broken database.
88 cache = tdb_open_log(cache_fname, 0,
89 TDB_DEFAULT|
90 TDB_INCOMPATIBLE_HASH|
91 TDB_CLEAR_IF_FIRST,
92 open_flags, 0644);
96 if (!cache && (errno == EACCES)) {
97 open_flags = O_RDONLY;
98 cache = tdb_open_log(cache_fname, 0, TDB_DEFAULT|TDB_INCOMPATIBLE_HASH, open_flags,
99 0644);
100 if (cache) {
101 DEBUG(5, ("gencache_init: Opening cache file %s read-only.\n", cache_fname));
105 if (!cache) {
106 DEBUG(5, ("Attempt to open gencache.tdb has failed.\n"));
107 return False;
110 cache_fname = lock_path("gencache_notrans.tdb");
112 DEBUG(5, ("Opening cache file at %s\n", cache_fname));
114 cache_notrans = tdb_open_log(cache_fname, 0,
115 TDB_CLEAR_IF_FIRST|
116 TDB_INCOMPATIBLE_HASH|
117 TDB_SEQNUM|
118 TDB_NOSYNC,
119 open_flags, 0644);
120 if (cache_notrans == NULL) {
121 DEBUG(5, ("Opening %s failed: %s\n", cache_fname,
122 strerror(errno)));
123 tdb_close(cache);
124 cache = NULL;
125 return false;
128 return True;
131 static TDB_DATA last_stabilize_key(void)
133 TDB_DATA result;
134 result.dptr = discard_const_p(uint8_t, "@LAST_STABILIZED");
135 result.dsize = 17;
136 return result;
139 struct gencache_have_val_state {
140 time_t new_timeout;
141 const DATA_BLOB *data;
142 bool gotit;
145 static void gencache_have_val_parser(time_t old_timeout, DATA_BLOB data,
146 void *private_data)
148 struct gencache_have_val_state *state =
149 (struct gencache_have_val_state *)private_data;
150 time_t now = time(NULL);
151 int cache_time_left, new_time_left, additional_time;
154 * Excuse the many variables, but these time calculations are
155 * confusing to me. We do not want to write to gencache with a
156 * possibly expensive transaction if we are about to write the same
157 * value, just extending the remaining timeout by less than 10%.
160 cache_time_left = old_timeout - now;
161 if (cache_time_left <= 0) {
163 * timed out, write new value
165 return;
168 new_time_left = state->new_timeout - now;
169 if (new_time_left <= 0) {
171 * Huh -- no new timeout?? Write it.
173 return;
176 if (new_time_left < cache_time_left) {
178 * Someone wants to shorten the timeout. Let it happen.
180 return;
184 * By how much does the new timeout extend the remaining cache time?
186 additional_time = new_time_left - cache_time_left;
188 if (additional_time * 10 < 0) {
190 * Integer overflow. We extend by so much that we have to write it.
192 return;
196 * The comparison below is essentially equivalent to
198 * new_time_left > cache_time_left * 1.10
200 * but without floating point calculations.
203 if (additional_time * 10 > cache_time_left) {
205 * We extend the cache timeout by more than 10%. Do it.
207 return;
211 * Now the more expensive data compare.
213 if (data_blob_cmp(state->data, &data) != 0) {
215 * Write a new value. Certainly do it.
217 return;
221 * Extending the timeout by less than 10% for the same cache value is
222 * not worth the trouble writing a value into gencache under a
223 * possibly expensive transaction.
225 state->gotit = true;
228 static bool gencache_have_val(const char *keystr, const DATA_BLOB *data,
229 time_t timeout)
231 struct gencache_have_val_state state;
233 state.new_timeout = timeout;
234 state.data = data;
235 state.gotit = false;
237 if (!gencache_parse(keystr, gencache_have_val_parser, &state)) {
238 return false;
240 return state.gotit;
244 * Set an entry in the cache file. If there's no such
245 * one, then add it.
247 * @param keystr string that represents a key of this entry
248 * @param blob DATA_BLOB value being cached
249 * @param timeout time when the value is expired
251 * @retval true when entry is successfuly stored
252 * @retval false on failure
255 bool gencache_set_data_blob(const char *keystr, const DATA_BLOB *blob,
256 time_t timeout)
258 int ret;
259 TDB_DATA databuf;
260 char* val;
261 time_t last_stabilize;
262 static int writecount;
264 if (tdb_data_cmp(string_term_tdb_data(keystr),
265 last_stabilize_key()) == 0) {
266 DEBUG(10, ("Can't store %s as a key\n", keystr));
267 return false;
270 if ((keystr == NULL) || (blob == NULL)) {
271 return false;
274 if (!gencache_init()) return False;
276 if (gencache_have_val(keystr, blob, timeout)) {
277 DEBUG(10, ("Did not store value for %s, we already got it\n",
278 keystr));
279 return true;
282 val = talloc_asprintf(talloc_tos(), CACHE_DATA_FMT, (int)timeout);
283 if (val == NULL) {
284 return False;
286 val = talloc_realloc(NULL, val, char, talloc_array_length(val)-1);
287 if (val == NULL) {
288 return false;
290 val = (char *)talloc_append_blob(NULL, val, *blob);
291 if (val == NULL) {
292 return false;
295 DEBUG(10, ("Adding cache entry with key=[%s] and timeout="
296 "[%s] (%d seconds %s)\n", keystr,
297 timestring(talloc_tos(), timeout),
298 (int)(timeout - time(NULL)),
299 timeout > time(NULL) ? "ahead" : "in the past"));
301 ret = tdb_store_bystring(
302 cache_notrans, keystr,
303 make_tdb_data((uint8_t *)val, talloc_array_length(val)),
305 TALLOC_FREE(val);
307 if (ret != 0) {
308 return false;
312 * Every 100 writes within a single process, stabilize the cache with
313 * a transaction. This is done to prevent a single transaction to
314 * become huge and chew lots of memory.
316 writecount += 1;
317 if (writecount > lp_parm_int(-1, "gencache", "stabilize_count", 100)) {
318 gencache_stabilize();
319 writecount = 0;
320 goto done;
324 * Every 5 minutes, call gencache_stabilize() to not let grow
325 * gencache_notrans.tdb too large.
328 last_stabilize = 0;
329 databuf = tdb_fetch_compat(cache_notrans, last_stabilize_key());
330 if ((databuf.dptr != NULL)
331 && (databuf.dptr[databuf.dsize-1] == '\0')) {
332 last_stabilize = atoi((char *)databuf.dptr);
333 SAFE_FREE(databuf.dptr);
335 if ((last_stabilize
336 + lp_parm_int(-1, "gencache", "stabilize_interval", 300))
337 < time(NULL)) {
338 gencache_stabilize();
341 done:
342 return ret == 0;
346 * Delete one entry from the cache file.
348 * @param keystr string that represents a key of this entry
350 * @retval true upon successful deletion
351 * @retval false in case of failure
354 bool gencache_del(const char *keystr)
356 bool exists, was_expired;
357 bool ret = false;
358 DATA_BLOB value;
360 if (keystr == NULL) {
361 return false;
364 if (!gencache_init()) return False;
366 DEBUG(10, ("Deleting cache entry (key=[%s])\n", keystr));
369 * We delete an element by setting its timeout to 0. This way we don't
370 * have to do a transaction on gencache.tdb every time we delete an
371 * element.
374 exists = gencache_get_data_blob(keystr, NULL, &value, NULL,
375 &was_expired);
377 if (!exists && was_expired) {
379 * gencache_get_data_blob has implicitly deleted this
380 * entry, so we have to return success here.
382 return true;
385 if (exists) {
386 data_blob_free(&value);
387 ret = gencache_set(keystr, "", 0);
389 return ret;
392 static bool gencache_pull_timeout(char *val, time_t *pres, char **pendptr)
394 time_t res;
395 char *endptr;
397 if (val == NULL) {
398 return false;
401 res = strtol(val, &endptr, 10);
403 if ((endptr == NULL) || (*endptr != '/')) {
404 DEBUG(2, ("Invalid gencache data format: %s\n", val));
405 return false;
407 if (pres != NULL) {
408 *pres = res;
410 if (pendptr != NULL) {
411 *pendptr = endptr;
413 return true;
416 struct gencache_parse_state {
417 void (*parser)(time_t timeout, DATA_BLOB blob, void *private_data);
418 void *private_data;
419 bool is_memcache;
422 static int gencache_parse_fn(TDB_DATA key, TDB_DATA data, void *private_data)
424 struct gencache_parse_state *state;
425 DATA_BLOB blob;
426 time_t t;
427 char *endptr;
428 bool ret;
430 if (data.dptr == NULL) {
431 return -1;
433 ret = gencache_pull_timeout((char *)data.dptr, &t, &endptr);
434 if (!ret) {
435 return -1;
437 state = (struct gencache_parse_state *)private_data;
438 blob = data_blob_const(
439 endptr+1, data.dsize - PTR_DIFF(endptr+1, data.dptr));
440 state->parser(t, blob, state->private_data);
442 if (!state->is_memcache) {
443 memcache_add(NULL, GENCACHE_RAM,
444 data_blob_const(key.dptr, key.dsize),
445 data_blob_const(data.dptr, data.dsize));
448 return 0;
451 bool gencache_parse(const char *keystr,
452 void (*parser)(time_t timeout, DATA_BLOB blob,
453 void *private_data),
454 void *private_data)
456 struct gencache_parse_state state;
457 TDB_DATA key = string_term_tdb_data(keystr);
458 DATA_BLOB memcache_val;
459 int ret;
461 if (keystr == NULL) {
462 return false;
464 if (tdb_data_cmp(key, last_stabilize_key()) == 0) {
465 return false;
467 if (!gencache_init()) {
468 return false;
471 state.parser = parser;
472 state.private_data = private_data;
474 if (memcache_lookup(NULL, GENCACHE_RAM,
475 data_blob_const(key.dptr, key.dsize),
476 &memcache_val)) {
478 * Make sure that nobody has changed the gencache behind our
479 * back.
481 int current_seqnum = tdb_get_seqnum(cache_notrans);
482 if (current_seqnum == cache_notrans_seqnum) {
484 * Ok, our memcache is still current, use it without
485 * going to the tdb files.
487 state.is_memcache = true;
488 gencache_parse_fn(key, make_tdb_data(memcache_val.data,
489 memcache_val.length),
490 &state);
491 return true;
493 memcache_flush(NULL, GENCACHE_RAM);
494 cache_notrans_seqnum = current_seqnum;
497 state.is_memcache = false;
499 ret = tdb_parse_record(cache_notrans, key, gencache_parse_fn, &state);
500 if (ret == 0) {
501 return true;
503 ret = tdb_parse_record(cache, key, gencache_parse_fn, &state);
504 return (ret == 0);
507 struct gencache_get_data_blob_state {
508 TALLOC_CTX *mem_ctx;
509 DATA_BLOB *blob;
510 time_t timeout;
511 bool result;
514 static void gencache_get_data_blob_parser(time_t timeout, DATA_BLOB blob,
515 void *private_data)
517 struct gencache_get_data_blob_state *state =
518 (struct gencache_get_data_blob_state *)private_data;
520 if (timeout == 0) {
521 state->result = false;
522 return;
524 state->timeout = timeout;
526 if (state->blob == NULL) {
527 state->result = true;
528 return;
531 *state->blob = data_blob_talloc(state->mem_ctx, blob.data,
532 blob.length);
533 if (state->blob->data == NULL) {
534 state->result = false;
535 return;
537 state->result = true;
541 * Get existing entry from the cache file.
543 * @param keystr string that represents a key of this entry
544 * @param blob DATA_BLOB that is filled with entry's blob
545 * @param timeout pointer to a time_t that is filled with entry's
546 * timeout
548 * @retval true when entry is successfuly fetched
549 * @retval False for failure
552 bool gencache_get_data_blob(const char *keystr, TALLOC_CTX *mem_ctx,
553 DATA_BLOB *blob,
554 time_t *timeout, bool *was_expired)
556 struct gencache_get_data_blob_state state;
557 bool expired = false;
559 state.result = false;
560 state.mem_ctx = mem_ctx;
561 state.blob = blob;
563 if (!gencache_parse(keystr, gencache_get_data_blob_parser, &state)) {
564 goto fail;
566 if (!state.result) {
567 goto fail;
569 if (state.timeout <= time(NULL)) {
571 * We're expired, delete the entry. We can't use gencache_del
572 * here, because that uses gencache_get_data_blob for checking
573 * the existence of a record. We know the thing exists and
574 * directly store an empty value with 0 timeout.
576 gencache_set(keystr, "", 0);
577 expired = true;
578 goto fail;
580 if (timeout) {
581 *timeout = state.timeout;
584 return True;
586 fail:
587 if (was_expired != NULL) {
588 *was_expired = expired;
590 if (state.result && state.blob) {
591 data_blob_free(state.blob);
593 return false;
596 struct stabilize_state {
597 bool written;
598 bool error;
600 static int stabilize_fn(struct tdb_context *tdb, TDB_DATA key, TDB_DATA val,
601 void *priv);
604 * Stabilize gencache
606 * Migrate the clear-if-first gencache data to the stable,
607 * transaction-based gencache.tdb
610 bool gencache_stabilize(void)
612 struct stabilize_state state;
613 int res;
614 char *now;
616 if (!gencache_init()) {
617 return false;
620 res = tdb_transaction_start_nonblock(cache);
621 if (res != 0) {
622 if (tdb_error(cache) == TDB_ERR_NOLOCK)
625 * Someone else already does the stabilize,
626 * this does not have to be done twice
628 return true;
631 DEBUG(10, ("Could not start transaction on gencache.tdb: "
632 "%s\n", tdb_errorstr_compat(cache)));
633 return false;
635 res = tdb_transaction_start(cache_notrans);
636 if (res != 0) {
637 tdb_transaction_cancel(cache);
638 DEBUG(10, ("Could not start transaction on "
639 "gencache_notrans.tdb: %s\n",
640 tdb_errorstr_compat(cache_notrans)));
641 return false;
644 state.error = false;
645 state.written = false;
647 res = tdb_traverse(cache_notrans, stabilize_fn, &state);
648 if ((res < 0) || state.error) {
649 tdb_transaction_cancel(cache_notrans);
650 tdb_transaction_cancel(cache);
651 return false;
654 if (!state.written) {
655 tdb_transaction_cancel(cache_notrans);
656 tdb_transaction_cancel(cache);
657 return true;
660 res = tdb_transaction_commit(cache);
661 if (res != 0) {
662 DEBUG(10, ("tdb_transaction_commit on gencache.tdb failed: "
663 "%s\n", tdb_errorstr_compat(cache)));
664 tdb_transaction_cancel(cache_notrans);
665 return false;
668 res = tdb_transaction_commit(cache_notrans);
669 if (res != 0) {
670 DEBUG(10, ("tdb_transaction_commit on gencache.tdb failed: "
671 "%s\n", tdb_errorstr_compat(cache)));
672 return false;
675 now = talloc_asprintf(talloc_tos(), "%d", (int)time(NULL));
676 if (now != NULL) {
677 tdb_store(cache_notrans, last_stabilize_key(),
678 string_term_tdb_data(now), 0);
679 TALLOC_FREE(now);
682 return true;
685 static int stabilize_fn(struct tdb_context *tdb, TDB_DATA key, TDB_DATA val,
686 void *priv)
688 struct stabilize_state *state = (struct stabilize_state *)priv;
689 int res;
690 time_t timeout;
692 if (tdb_data_cmp(key, last_stabilize_key()) == 0) {
693 return 0;
696 if (!gencache_pull_timeout((char *)val.dptr, &timeout, NULL)) {
697 DEBUG(10, ("Ignoring invalid entry\n"));
698 return 0;
700 if ((timeout < time(NULL)) || (val.dsize == 0)) {
701 res = tdb_delete(cache, key);
702 if ((res != 0) && (tdb_error(cache) == TDB_ERR_NOEXIST)) {
703 res = 0;
704 } else {
705 state->written = true;
707 } else {
708 res = tdb_store(cache, key, val, 0);
709 if (res == 0) {
710 state->written = true;
714 if (res != 0) {
715 DEBUG(10, ("Transfer to gencache.tdb failed: %s\n",
716 tdb_errorstr_compat(cache)));
717 state->error = true;
718 return -1;
721 if (tdb_delete(cache_notrans, key) != 0) {
722 DEBUG(10, ("tdb_delete from gencache_notrans.tdb failed: "
723 "%s\n", tdb_errorstr_compat(cache_notrans)));
724 state->error = true;
725 return -1;
727 return 0;
731 * Get existing entry from the cache file.
733 * @param keystr string that represents a key of this entry
734 * @param valstr buffer that is allocated and filled with the entry value
735 * buffer's disposing must be done outside
736 * @param timeout pointer to a time_t that is filled with entry's
737 * timeout
739 * @retval true when entry is successfuly fetched
740 * @retval False for failure
743 bool gencache_get(const char *keystr, TALLOC_CTX *mem_ctx, char **value,
744 time_t *ptimeout)
746 DATA_BLOB blob;
747 bool ret = False;
749 ret = gencache_get_data_blob(keystr, mem_ctx, &blob, ptimeout, NULL);
750 if (!ret) {
751 return false;
753 if ((blob.data == NULL) || (blob.length == 0)) {
754 data_blob_free(&blob);
755 return false;
757 if (blob.data[blob.length-1] != '\0') {
758 /* Not NULL terminated, can't be a string */
759 data_blob_free(&blob);
760 return false;
762 if (value) {
764 * talloc_move generates a type-punned warning here. As we
765 * leave the function immediately, do a simple talloc_steal.
767 *value = (char *)talloc_steal(mem_ctx, blob.data);
768 return true;
770 data_blob_free(&blob);
771 return true;
775 * Set an entry in the cache file. If there's no such
776 * one, then add it.
778 * @param keystr string that represents a key of this entry
779 * @param value text representation value being cached
780 * @param timeout time when the value is expired
782 * @retval true when entry is successfuly stored
783 * @retval false on failure
786 bool gencache_set(const char *keystr, const char *value, time_t timeout)
788 DATA_BLOB blob = data_blob_const(value, strlen(value)+1);
789 return gencache_set_data_blob(keystr, &blob, timeout);
792 struct gencache_iterate_blobs_state {
793 void (*fn)(const char *key, DATA_BLOB value,
794 time_t timeout, void *private_data);
795 const char *pattern;
796 void *private_data;
797 bool in_persistent;
800 static int gencache_iterate_blobs_fn(struct tdb_context *tdb, TDB_DATA key,
801 TDB_DATA data, void *priv)
803 struct gencache_iterate_blobs_state *state =
804 (struct gencache_iterate_blobs_state *)priv;
805 char *keystr;
806 char *free_key = NULL;
807 time_t timeout;
808 char *endptr;
810 if (tdb_data_cmp(key, last_stabilize_key()) == 0) {
811 return 0;
813 if (state->in_persistent && tdb_exists(cache_notrans, key)) {
814 return 0;
817 if (key.dptr[key.dsize-1] == '\0') {
818 keystr = (char *)key.dptr;
819 } else {
820 /* ensure 0-termination */
821 keystr = talloc_strndup(talloc_tos(), (char *)key.dptr, key.dsize);
822 free_key = keystr;
823 if (keystr == NULL) {
824 goto done;
828 if (!gencache_pull_timeout((char *)data.dptr, &timeout, &endptr)) {
829 goto done;
831 endptr += 1;
833 if (fnmatch(state->pattern, keystr, 0) != 0) {
834 goto done;
837 DEBUG(10, ("Calling function with arguments "
838 "(key=[%s], timeout=[%s])\n",
839 keystr, timestring(talloc_tos(), timeout)));
841 state->fn(keystr,
842 data_blob_const(endptr,
843 data.dsize - PTR_DIFF(endptr, data.dptr)),
844 timeout, state->private_data);
846 done:
847 TALLOC_FREE(free_key);
848 return 0;
851 void gencache_iterate_blobs(void (*fn)(const char *key, DATA_BLOB value,
852 time_t timeout, void *private_data),
853 void *private_data, const char *pattern)
855 struct gencache_iterate_blobs_state state;
857 if ((fn == NULL) || (pattern == NULL) || !gencache_init()) {
858 return;
861 DEBUG(5, ("Searching cache keys with pattern %s\n", pattern));
863 state.fn = fn;
864 state.pattern = pattern;
865 state.private_data = private_data;
867 state.in_persistent = false;
868 tdb_traverse(cache_notrans, gencache_iterate_blobs_fn, &state);
870 state.in_persistent = true;
871 tdb_traverse(cache, gencache_iterate_blobs_fn, &state);
875 * Iterate through all entries which key matches to specified pattern
877 * @param fn pointer to the function that will be supplied with each single
878 * matching cache entry (key, value and timeout) as an arguments
879 * @param data void pointer to an arbitrary data that is passed directly to the fn
880 * function on each call
881 * @param keystr_pattern pattern the existing entries' keys are matched to
885 struct gencache_iterate_state {
886 void (*fn)(const char *key, const char *value, time_t timeout,
887 void *priv);
888 void *private_data;
891 static void gencache_iterate_fn(const char *key, DATA_BLOB value,
892 time_t timeout, void *private_data)
894 struct gencache_iterate_state *state =
895 (struct gencache_iterate_state *)private_data;
896 char *valstr;
897 char *free_val = NULL;
899 if (value.data[value.length-1] == '\0') {
900 valstr = (char *)value.data;
901 } else {
902 /* ensure 0-termination */
903 valstr = talloc_strndup(talloc_tos(), (char *)value.data, value.length);
904 free_val = valstr;
905 if (valstr == NULL) {
906 goto done;
910 DEBUG(10, ("Calling function with arguments "
911 "(key=[%s], value=[%s], timeout=[%s])\n",
912 key, valstr, timestring(talloc_tos(), timeout)));
914 state->fn(key, valstr, timeout, state->private_data);
916 done:
918 TALLOC_FREE(free_val);
921 void gencache_iterate(void (*fn)(const char *key, const char *value,
922 time_t timeout, void *dptr),
923 void *private_data, const char *pattern)
925 struct gencache_iterate_state state;
927 if (fn == NULL) {
928 return;
930 state.fn = fn;
931 state.private_data = private_data;
932 gencache_iterate_blobs(gencache_iterate_fn, &state, pattern);