source: branches/samba-3.3.x/source/smbd/statcache.c@ 302

Last change on this file since 302 was 206, checked in by Herwig Bauernfeind, 16 years ago

Import Samba 3.3 branch at 3.0.0 level (psmedley's port)
File size: 9.8 KB
Line 
1/*
2 Unix SMB/CIFS implementation.
3 stat cache code
4 Copyright (C) Andrew Tridgell 1992-2000
5 Copyright (C) Jeremy Allison 1999-2007
6 Copyright (C) Andrew Bartlett <abartlet@samba.org> 2003
7 Copyright (C) Volker Lendecke 2007
8
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
13
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>.
21*/
22
23#include "includes.h"
24
25/****************************************************************************
26 Stat cache code used in unix_convert.
27*****************************************************************************/
28
29/**
30 * Add an entry into the stat cache.
31 *
32 * @param full_orig_name The original name as specified by the client
33 * @param orig_translated_path The name on our filesystem.
34 *
35 * @note Only the first strlen(orig_translated_path) characters are stored
36 * into the cache. This means that full_orig_name will be internally
37 * truncated.
38 *
39 */
40
41void stat_cache_add( const char *full_orig_name,
42 char *translated_path,
43 bool case_sensitive)
44{
45 size_t translated_path_length;
46 char *original_path;
47 size_t original_path_length;
48 char saved_char;
49 TALLOC_CTX *ctx = talloc_tos();
50
51 if (!lp_stat_cache()) {
52 return;
53 }
54
55 /*
56 * Don't cache trivial valid directory entries such as . and ..
57 */
58
59 if ((*full_orig_name == '\0')
60 || ISDOT(full_orig_name) || ISDOTDOT(full_orig_name)) {
61 return;
62 }
63
64 /*
65 * If we are in case insentive mode, we don't need to
66 * store names that need no translation - else, it
67 * would be a waste.
68 */
69
70 if (case_sensitive && (strcmp(full_orig_name, translated_path) == 0)) {
71 return;
72 }
73
74 /*
75 * Remove any trailing '/' characters from the
76 * translated path.
77 */
78
79 translated_path_length = strlen(translated_path);
80
81 if(translated_path[translated_path_length-1] == '/') {
82 translated_path_length--;
83 }
84
85 if(case_sensitive) {
86 original_path = talloc_strdup(ctx,full_orig_name);
87 } else {
88 original_path = talloc_strdup_upper(ctx,full_orig_name);
89 }
90
91 if (!original_path) {
92 return;
93 }
94
95 original_path_length = strlen(original_path);
96
97 if(original_path[original_path_length-1] == '/') {
98 original_path[original_path_length-1] = '\0';
99 original_path_length--;
100 }
101
102 if (original_path_length != translated_path_length) {
103 if (original_path_length < translated_path_length) {
104 DEBUG(0, ("OOPS - tried to store stat cache entry "
105 "for weird length paths [%s] %lu and [%s] %lu)!\n",
106 original_path,
107 (unsigned long)original_path_length,
108 translated_path,
109 (unsigned long)translated_path_length));
110 TALLOC_FREE(original_path);
111 return;
112 }
113
114 /* we only want to index by the first part of original_path,
115 up to the length of translated_path */
116
117 original_path[translated_path_length] = '\0';
118 original_path_length = translated_path_length;
119 }
120
121 /* Ensure we're null terminated. */
122 saved_char = translated_path[translated_path_length];
123 translated_path[translated_path_length] = '\0';
124
125 /*
126 * New entry or replace old entry.
127 */
128
129 memcache_add(
130 smbd_memcache(), STAT_CACHE,
131 data_blob_const(original_path, original_path_length),
132 data_blob_const(translated_path, translated_path_length + 1));
133
134 DEBUG(5,("stat_cache_add: Added entry (%lx:size %x) %s -> %s\n",
135 (unsigned long)translated_path,
136 (unsigned int)translated_path_length,
137 original_path,
138 translated_path));
139
140 translated_path[translated_path_length] = saved_char;
141 TALLOC_FREE(original_path);
142}
143
144/**
145 * Look through the stat cache for an entry
146 *
147 * @param conn A connection struct to do the stat() with.
148 * @param name The path we are attempting to cache, modified by this routine
149 * to be correct as far as the cache can tell us. We assume that
150 * it is a talloc'ed string from top of stack, we free it if
151 * necessary.
152 * @param dirpath The path as far as the stat cache told us. Also talloced
153 * from top of stack.
154 * @param start A pointer into name, for where to 'start' in fixing the rest
155 * of the name up.
156 * @param psd A stat buffer, NOT from the cache, but just a side-effect.
157 *
158 * @return True if we translated (and did a scuccessful stat on) the entire
159 * name.
160 *
161 */
162
163bool stat_cache_lookup(connection_struct *conn,
164 char **pp_name,
165 char **pp_dirpath,
166 char **pp_start,
167 SMB_STRUCT_STAT *pst)
168{
169 char *chk_name;
170 size_t namelen;
171 bool sizechanged = False;
172 unsigned int num_components = 0;
173 char *translated_path;
174 size_t translated_path_length;
175 DATA_BLOB data_val;
176 char *name;
177 TALLOC_CTX *ctx = talloc_tos();
178
179 *pp_dirpath = NULL;
180 *pp_start = *pp_name;
181
182 if (!lp_stat_cache()) {
183 return False;
184 }
185
186 name = *pp_name;
187 namelen = strlen(name);
188
189 DO_PROFILE_INC(statcache_lookups);
190
191 /*
192 * Don't lookup trivial valid directory entries.
193 */
194 if ((*name == '\0') || ISDOT(name) || ISDOTDOT(name)) {
195 return False;
196 }
197
198 if (conn->case_sensitive) {
199 chk_name = talloc_strdup(ctx,name);
200 if (!chk_name) {
201 DEBUG(0, ("stat_cache_lookup: strdup failed!\n"));
202 return False;
203 }
204
205 } else {
206 chk_name = talloc_strdup_upper(ctx,name);
207 if (!chk_name) {
208 DEBUG(0, ("stat_cache_lookup: strdup_upper failed!\n"));
209 return False;
210 }
211
212 /*
213 * In some language encodings the length changes
214 * if we uppercase. We need to treat this differently
215 * below.
216 */
217 if (strlen(chk_name) != namelen) {
218 sizechanged = True;
219 }
220 }
221
222 while (1) {
223 char *sp;
224
225 data_val = data_blob_null;
226
227 if (memcache_lookup(
228 smbd_memcache(), STAT_CACHE,
229 data_blob_const(chk_name, strlen(chk_name)),
230 &data_val)) {
231 break;
232 }
233
234 DEBUG(10,("stat_cache_lookup: lookup failed for name [%s]\n",
235 chk_name ));
236 /*
237 * Didn't find it - remove last component for next try.
238 */
239 if (!(sp = strrchr_m(chk_name, '/'))) {
240 /*
241 * We reached the end of the name - no match.
242 */
243 DO_PROFILE_INC(statcache_misses);
244 TALLOC_FREE(chk_name);
245 return False;
246 }
247
248 *sp = '\0';
249
250 /*
251 * Count the number of times we have done this, we'll
252 * need it when reconstructing the string.
253 */
254
255 if (sizechanged) {
256 num_components++;
257 }
258
259 if ((*chk_name == '\0')
260 || ISDOT(chk_name) || ISDOTDOT(chk_name)) {
261 DO_PROFILE_INC(statcache_misses);
262 TALLOC_FREE(chk_name);
263 return False;
264 }
265 }
266
267 translated_path = talloc_strdup(ctx,(char *)data_val.data);
268 if (!translated_path) {
269 smb_panic("talloc failed");
270 }
271 translated_path_length = data_val.length - 1;
272
273 DEBUG(10,("stat_cache_lookup: lookup succeeded for name [%s] "
274 "-> [%s]\n", chk_name, translated_path ));
275 DO_PROFILE_INC(statcache_hits);
276
277 if (SMB_VFS_STAT(conn, translated_path, pst) != 0) {
278 /* Discard this entry - it doesn't exist in the filesystem. */
279 memcache_delete(smbd_memcache(), STAT_CACHE,
280 data_blob_const(chk_name, strlen(chk_name)));
281 TALLOC_FREE(chk_name);
282 TALLOC_FREE(translated_path);
283 return False;
284 }
285
286 if (!sizechanged) {
287 memcpy(*pp_name, translated_path,
288 MIN(namelen, translated_path_length));
289 } else {
290 if (num_components == 0) {
291 name = talloc_strndup(ctx, translated_path,
292 translated_path_length);
293 } else {
294 char *sp;
295
296 sp = strnrchr_m(name, '/', num_components);
297 if (sp) {
298 name = talloc_asprintf(ctx,"%.*s%s",
299 (int)translated_path_length,
300 translated_path, sp);
301 } else {
302 name = talloc_strndup(ctx,
303 translated_path,
304 translated_path_length);
305 }
306 }
307 if (name == NULL) {
308 /*
309 * TODO: Get us out of here with a real error message
310 */
311 smb_panic("talloc failed");
312 }
313 TALLOC_FREE(*pp_name);
314 *pp_name = name;
315 }
316
317
318 /* set pointer for 'where to start' on fixing the rest of the name */
319 *pp_start = &name[translated_path_length];
320 if (**pp_start == '/') {
321 ++*pp_start;
322 }
323
324 *pp_dirpath = translated_path;
325 TALLOC_FREE(chk_name);
326 return (namelen == translated_path_length);
327}
328
329/***************************************************************************
330 Tell all smbd's to delete an entry.
331**************************************************************************/
332
333void send_stat_cache_delete_message(const char *name)
334{
335#ifdef DEVELOPER
336 message_send_all(smbd_messaging_context(),
337 MSG_SMB_STAT_CACHE_DELETE,
338 name,
339 strlen(name)+1,
340 NULL);
341#endif
342}
343
344/***************************************************************************
345 Delete an entry.
346**************************************************************************/
347
348void stat_cache_delete(const char *name)
349{
350 char *lname = talloc_strdup_upper(talloc_tos(), name);
351
352 if (!lname) {
353 return;
354 }
355 DEBUG(10,("stat_cache_delete: deleting name [%s] -> %s\n",
356 lname, name ));
357
358 memcache_delete(smbd_memcache(), STAT_CACHE,
359 data_blob_const(lname, talloc_get_size(lname)-1));
360 TALLOC_FREE(lname);
361}
362
363/***************************************************************
364 Compute a hash value based on a string key value.
365 The function returns the bucket index number for the hashed key.
366 JRA. Use a djb-algorithm hash for speed.
367***************************************************************/
368
369unsigned int fast_string_hash(TDB_DATA *key)
370{
371 unsigned int n = 0;
372 const char *p;
373 for (p = (const char *)key->dptr; *p != '\0'; p++) {
374 n = ((n << 5) + n) ^ (unsigned int)(*p);
375 }
376 return n;
377}
378
379/***************************************************************************
380 Initializes or clears the stat cache.
381**************************************************************************/
382
383bool reset_stat_cache( void )
384{
385 if (!lp_stat_cache())
386 return True;
387
388 memcache_flush(smbd_memcache(), STAT_CACHE);
389
390 return True;
391}
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