2 Unix SMB/CIFS implementation.
4 Copyright (C) Volker Lendecke 2007
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
22 #include "../lib/util/debug.h"
23 #include "../lib/util/samba_util.h"
24 #include "../lib/util/dlinklist.h"
25 #include "../lib/util/rbtree.h"
28 static struct memcache *global_cache;
30 struct memcache_talloc_value {
35 struct memcache_element {
36 struct rb_node rb_node;
37 struct memcache_element *prev, *next;
38 size_t keylength, valuelength;
39 uint8_t n; /* This is really an enum, but save memory */
40 char data[1]; /* placeholder for offsetof */
44 struct memcache_element *mru;
50 static void memcache_element_parse(struct memcache_element *e,
51 DATA_BLOB *key, DATA_BLOB *value);
53 static bool memcache_is_talloc(enum memcache_number n)
59 case PDB_GETPWSID_CACHE:
60 case SINGLETON_CACHE_TALLOC:
61 case SHARE_MODE_LOCK_CACHE:
63 case VIRUSFILTER_SCAN_RESULTS_CACHE_TALLOC:
74 static int memcache_destructor(struct memcache *cache) {
75 struct memcache_element *e, *next;
77 for (e = cache->mru; e != NULL; e = next) {
84 struct memcache *memcache_init(TALLOC_CTX *mem_ctx, size_t max_size)
86 struct memcache *result;
88 result = talloc_zero(mem_ctx, struct memcache);
92 result->max_size = max_size;
93 talloc_set_destructor(result, memcache_destructor);
97 void memcache_set_global(struct memcache *cache)
99 TALLOC_FREE(global_cache);
100 global_cache = cache;
103 static struct memcache_element *memcache_node2elem(struct rb_node *node)
105 return (struct memcache_element *)
106 ((char *)node - offsetof(struct memcache_element, rb_node));
109 static void memcache_element_parse(struct memcache_element *e,
110 DATA_BLOB *key, DATA_BLOB *value)
112 key->data = ((uint8_t *)e) + offsetof(struct memcache_element, data);
113 key->length = e->keylength;
114 value->data = key->data + e->keylength;
115 value->length = e->valuelength;
118 static size_t memcache_element_size(size_t key_length, size_t value_length)
120 return sizeof(struct memcache_element) - 1 + key_length + value_length;
123 static int memcache_compare(struct memcache_element *e, enum memcache_number n,
126 DATA_BLOB this_key, this_value;
128 if ((int)e->n < (int)n) return 1;
129 if ((int)e->n > (int)n) return -1;
131 if (e->keylength < key.length) return 1;
132 if (e->keylength > key.length) return -1;
134 memcache_element_parse(e, &this_key, &this_value);
135 return memcmp(this_key.data, key.data, key.length);
138 static struct memcache_element *memcache_find(
139 struct memcache *cache, enum memcache_number n, DATA_BLOB key)
141 struct rb_node *node;
143 node = cache->tree.rb_node;
145 while (node != NULL) {
146 struct memcache_element *elem = memcache_node2elem(node);
149 cmp = memcache_compare(elem, n, key);
153 node = (cmp < 0) ? node->rb_left : node->rb_right;
159 bool memcache_lookup(struct memcache *cache, enum memcache_number n,
160 DATA_BLOB key, DATA_BLOB *value)
162 struct memcache_element *e;
165 cache = global_cache;
171 e = memcache_find(cache, n, key);
176 if (cache->size != 0) {
177 DLIST_PROMOTE(cache->mru, e);
180 memcache_element_parse(e, &key, value);
184 void *memcache_lookup_talloc(struct memcache *cache, enum memcache_number n,
188 struct memcache_talloc_value mtv;
190 if (!memcache_lookup(cache, n, key, &value)) {
194 if (value.length != sizeof(mtv)) {
198 memcpy(&mtv, value.data, sizeof(mtv));
203 static void memcache_delete_element(struct memcache *cache,
204 struct memcache_element *e)
206 rb_erase(&e->rb_node, &cache->tree);
208 DLIST_REMOVE(cache->mru, e);
210 if (memcache_is_talloc(e->n)) {
211 DATA_BLOB cache_key, cache_value;
212 struct memcache_talloc_value mtv;
214 memcache_element_parse(e, &cache_key, &cache_value);
215 SMB_ASSERT(cache_value.length == sizeof(mtv));
216 memcpy(&mtv, cache_value.data, sizeof(mtv));
217 cache->size -= mtv.len;
218 TALLOC_FREE(mtv.ptr);
221 cache->size -= memcache_element_size(e->keylength, e->valuelength);
226 static void memcache_trim(struct memcache *cache)
228 if (cache->max_size == 0) {
232 while ((cache->size > cache->max_size) && DLIST_TAIL(cache->mru)) {
233 memcache_delete_element(cache, DLIST_TAIL(cache->mru));
237 void memcache_delete(struct memcache *cache, enum memcache_number n,
240 struct memcache_element *e;
243 cache = global_cache;
249 e = memcache_find(cache, n, key);
254 memcache_delete_element(cache, e);
257 void memcache_add(struct memcache *cache, enum memcache_number n,
258 DATA_BLOB key, DATA_BLOB value)
260 struct memcache_element *e;
262 struct rb_node *parent;
263 DATA_BLOB cache_key, cache_value;
267 cache = global_cache;
273 if (key.length == 0) {
277 e = memcache_find(cache, n, key);
280 memcache_element_parse(e, &cache_key, &cache_value);
282 if (value.length <= cache_value.length) {
283 if (memcache_is_talloc(e->n)) {
284 struct memcache_talloc_value mtv;
286 SMB_ASSERT(cache_value.length == sizeof(mtv));
287 memcpy(&mtv, cache_value.data, sizeof(mtv));
288 cache->size -= mtv.len;
289 TALLOC_FREE(mtv.ptr);
292 * We can reuse the existing record
294 memcpy(cache_value.data, value.data, value.length);
295 e->valuelength = value.length;
297 if (memcache_is_talloc(e->n)) {
298 struct memcache_talloc_value mtv;
300 SMB_ASSERT(cache_value.length == sizeof(mtv));
301 memcpy(&mtv, cache_value.data, sizeof(mtv));
302 cache->size += mtv.len;
307 memcache_delete_element(cache, e);
310 element_size = memcache_element_size(key.length, value.length);
312 e = talloc_size(cache, element_size);
314 DEBUG(0, ("talloc failed\n"));
317 talloc_set_type(e, struct memcache_element);
320 e->keylength = key.length;
321 e->valuelength = value.length;
323 memcache_element_parse(e, &cache_key, &cache_value);
324 memcpy(cache_key.data, key.data, key.length);
325 memcpy(cache_value.data, value.data, value.length);
328 p = &cache->tree.rb_node;
331 struct memcache_element *elem = memcache_node2elem(*p);
336 cmp = memcache_compare(elem, n, key);
338 p = (cmp < 0) ? &(*p)->rb_left : &(*p)->rb_right;
341 rb_link_node(&e->rb_node, parent, p);
342 rb_insert_color(&e->rb_node, &cache->tree);
344 DLIST_ADD(cache->mru, e);
346 cache->size += element_size;
347 if (memcache_is_talloc(e->n)) {
348 struct memcache_talloc_value mtv;
350 SMB_ASSERT(cache_value.length == sizeof(mtv));
351 memcpy(&mtv, cache_value.data, sizeof(mtv));
352 cache->size += mtv.len;
354 memcache_trim(cache);
357 void memcache_add_talloc(struct memcache *cache, enum memcache_number n,
358 DATA_BLOB key, void *pptr)
360 struct memcache_talloc_value mtv;
361 void **ptr = (void **)pptr;
364 cache = global_cache;
370 mtv.len = talloc_total_size(*ptr);
371 mtv.ptr = talloc_move(cache, ptr);
372 memcache_add(cache, n, key, data_blob_const(&mtv, sizeof(mtv)));
375 void memcache_flush(struct memcache *cache, enum memcache_number n)
377 struct rb_node *node;
380 cache = global_cache;
387 * Find the smallest element of number n
390 node = cache->tree.rb_node;
396 * First, find *any* element of number n
400 struct memcache_element *elem = memcache_node2elem(node);
401 struct rb_node *next;
403 if ((int)elem->n == (int)n) {
407 if ((int)elem->n < (int)n) {
408 next = node->rb_right;
411 next = node->rb_left;
420 * Then, find the leftmost element with number n
424 struct rb_node *prev = rb_prev(node);
425 struct memcache_element *elem;
430 elem = memcache_node2elem(prev);
431 if ((int)elem->n != (int)n) {
437 while (node != NULL) {
438 struct memcache_element *e = memcache_node2elem(node);
439 struct rb_node *next = rb_next(node);
445 memcache_delete_element(cache, e);