source: vendor/3.6.23/source3/smbd/statcache.c

Last change on this file was 746, checked in by Silvan Scherrer, 13 years ago

Samba Server: updated vendor to 3.6.9
File size: 10.7 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#include "memcache.h"
25#include "smbd/smbd.h"
26#include "messages.h"
27#include "smbprofile.h"
28#include <tdb.h>
29
30/****************************************************************************
31 Stat cache code used in unix_convert.
32*****************************************************************************/
33
34/**
35 * Add an entry into the stat cache.
36 *
37 * @param full_orig_name The original name as specified by the client
38 * @param orig_translated_path The name on our filesystem.
39 *
40 * @note Only the first strlen(orig_translated_path) characters are stored
41 * into the cache. This means that full_orig_name will be internally
42 * truncated.
43 *
44 */
45
46void stat_cache_add( const char *full_orig_name,
47 char *translated_path,
48 bool case_sensitive)
49{
50 size_t translated_path_length;
51 char *original_path;
52 size_t original_path_length;
53 char saved_char;
54 TALLOC_CTX *ctx = talloc_tos();
55
56 if (!lp_stat_cache()) {
57 return;
58 }
59
60 /*
61 * Don't cache trivial valid directory entries such as . and ..
62 */
63
64 if ((*full_orig_name == '\0')
65 || ISDOT(full_orig_name) || ISDOTDOT(full_orig_name)) {
66 return;
67 }
68
69 /*
70 * If we are in case insentive mode, we don't need to
71 * store names that need no translation - else, it
72 * would be a waste.
73 */
74
75 if (case_sensitive && (strcmp(full_orig_name, translated_path) == 0)) {
76 return;
77 }
78
79 /*
80 * Remove any trailing '/' characters from the
81 * translated path.
82 */
83
84 translated_path_length = strlen(translated_path);
85
86 if(translated_path[translated_path_length-1] == '/') {
87 translated_path_length--;
88 }
89
90 if(case_sensitive) {
91 original_path = talloc_strdup(ctx,full_orig_name);
92 } else {
93 original_path = talloc_strdup_upper(ctx,full_orig_name);
94 }
95
96 if (!original_path) {
97 return;
98 }
99
100 original_path_length = strlen(original_path);
101
102 if(original_path[original_path_length-1] == '/') {
103 original_path[original_path_length-1] = '\0';
104 original_path_length--;
105 }
106
107 if (original_path_length != translated_path_length) {
108 if (original_path_length < translated_path_length) {
109 DEBUG(0, ("OOPS - tried to store stat cache entry "
110 "for weird length paths [%s] %lu and [%s] %lu)!\n",
111 original_path,
112 (unsigned long)original_path_length,
113 translated_path,
114 (unsigned long)translated_path_length));
115 TALLOC_FREE(original_path);
116 return;
117 }
118
119 /* we only want to index by the first part of original_path,
120 up to the length of translated_path */
121
122 original_path[translated_path_length] = '\0';
123 original_path_length = translated_path_length;
124 }
125
126 /* Ensure we're null terminated. */
127 saved_char = translated_path[translated_path_length];
128 translated_path[translated_path_length] = '\0';
129
130 /*
131 * New entry or replace old entry.
132 */
133
134 memcache_add(
135 smbd_memcache(), STAT_CACHE,
136 data_blob_const(original_path, original_path_length),
137 data_blob_const(translated_path, translated_path_length + 1));
138
139 DEBUG(5,("stat_cache_add: Added entry (%lx:size %x) %s -> %s\n",
140 (unsigned long)translated_path,
141 (unsigned int)translated_path_length,
142 original_path,
143 translated_path));
144
145 translated_path[translated_path_length] = saved_char;
146 TALLOC_FREE(original_path);
147}
148
149/**
150 * Look through the stat cache for an entry
151 *
152 * @param conn A connection struct to do the stat() with.
153 * @param posix_paths Whether to lookup using stat() or lstat()
154 * @param name The path we are attempting to cache, modified by this routine
155 * to be correct as far as the cache can tell us. We assume that
156 * it is a talloc'ed string from top of stack, we free it if
157 * necessary.
158 * @param dirpath The path as far as the stat cache told us. Also talloced
159 * from top of stack.
160 * @param start A pointer into name, for where to 'start' in fixing the rest
161 * of the name up.
162 * @param psd A stat buffer, NOT from the cache, but just a side-effect.
163 *
164 * @return True if we translated (and did a scuccessful stat on) the entire
165 * name.
166 *
167 */
168
169bool stat_cache_lookup(connection_struct *conn,
170 bool posix_paths,
171 char **pp_name,
172 char **pp_dirpath,
173 char **pp_start,
174 SMB_STRUCT_STAT *pst)
175{
176 char *chk_name;
177 size_t namelen;
178 bool sizechanged = False;
179 unsigned int num_components = 0;
180 char *translated_path;
181 size_t translated_path_length;
182 DATA_BLOB data_val;
183 char *name;
184 TALLOC_CTX *ctx = talloc_tos();
185 struct smb_filename smb_fname;
186 int ret;
187
188 *pp_dirpath = NULL;
189 *pp_start = *pp_name;
190
191 if (!lp_stat_cache()) {
192 return False;
193 }
194
195 name = *pp_name;
196 namelen = strlen(name);
197
198 DO_PROFILE_INC(statcache_lookups);
199
200 /*
201 * Don't lookup trivial valid directory entries.
202 */
203 if ((*name == '\0') || ISDOT(name) || ISDOTDOT(name)) {
204 return False;
205 }
206
207 if (conn->case_sensitive) {
208 chk_name = talloc_strdup(ctx,name);
209 if (!chk_name) {
210 DEBUG(0, ("stat_cache_lookup: strdup failed!\n"));
211 return False;
212 }
213
214 } else {
215 chk_name = talloc_strdup_upper(ctx,name);
216 if (!chk_name) {
217 DEBUG(0, ("stat_cache_lookup: talloc_strdup_upper failed!\n"));
218 return False;
219 }
220
221 /*
222 * In some language encodings the length changes
223 * if we uppercase. We need to treat this differently
224 * below.
225 */
226 if (strlen(chk_name) != namelen) {
227 sizechanged = True;
228 }
229 }
230
231 while (1) {
232 char *sp;
233
234 data_val = data_blob_null;
235
236 if (memcache_lookup(
237 smbd_memcache(), STAT_CACHE,
238 data_blob_const(chk_name, strlen(chk_name)),
239 &data_val)) {
240 break;
241 }
242
243 DEBUG(10,("stat_cache_lookup: lookup failed for name [%s]\n",
244 chk_name ));
245 /*
246 * Didn't find it - remove last component for next try.
247 */
248 if (!(sp = strrchr_m(chk_name, '/'))) {
249 /*
250 * We reached the end of the name - no match.
251 */
252 DO_PROFILE_INC(statcache_misses);
253 TALLOC_FREE(chk_name);
254 return False;
255 }
256
257 *sp = '\0';
258
259 /*
260 * Count the number of times we have done this, we'll
261 * need it when reconstructing the string.
262 */
263
264 if (sizechanged) {
265 num_components++;
266 }
267
268 if ((*chk_name == '\0')
269 || ISDOT(chk_name) || ISDOTDOT(chk_name)) {
270 DO_PROFILE_INC(statcache_misses);
271 TALLOC_FREE(chk_name);
272 return False;
273 }
274 }
275
276 translated_path = talloc_strdup(ctx,(char *)data_val.data);
277 if (!translated_path) {
278 smb_panic("talloc failed");
279 }
280 translated_path_length = data_val.length - 1;
281
282 DEBUG(10,("stat_cache_lookup: lookup succeeded for name [%s] "
283 "-> [%s]\n", chk_name, translated_path ));
284 DO_PROFILE_INC(statcache_hits);
285
286 ZERO_STRUCT(smb_fname);
287 smb_fname.base_name = translated_path;
288
289 if (posix_paths) {
290 ret = SMB_VFS_LSTAT(conn, &smb_fname);
291 } else {
292 ret = SMB_VFS_STAT(conn, &smb_fname);
293 }
294
295 if (ret != 0) {
296 /* Discard this entry - it doesn't exist in the filesystem. */
297 memcache_delete(smbd_memcache(), STAT_CACHE,
298 data_blob_const(chk_name, strlen(chk_name)));
299 TALLOC_FREE(chk_name);
300 TALLOC_FREE(translated_path);
301 return False;
302 }
303 *pst = smb_fname.st;
304
305 if (!sizechanged) {
306 memcpy(*pp_name, translated_path,
307 MIN(namelen, translated_path_length));
308 } else {
309 if (num_components == 0) {
310 name = talloc_strndup(ctx, translated_path,
311 translated_path_length);
312 } else {
313 char *sp;
314
315 sp = strnrchr_m(name, '/', num_components);
316 if (sp) {
317 name = talloc_asprintf(ctx,"%.*s%s",
318 (int)translated_path_length,
319 translated_path, sp);
320 } else {
321 name = talloc_strndup(ctx,
322 translated_path,
323 translated_path_length);
324 }
325 }
326 if (name == NULL) {
327 /*
328 * TODO: Get us out of here with a real error message
329 */
330 smb_panic("talloc failed");
331 }
332 TALLOC_FREE(*pp_name);
333 *pp_name = name;
334 }
335
336
337 /* set pointer for 'where to start' on fixing the rest of the name */
338 *pp_start = &name[translated_path_length];
339 if (**pp_start == '/') {
340 ++*pp_start;
341 }
342
343 *pp_dirpath = translated_path;
344 TALLOC_FREE(chk_name);
345 return (namelen == translated_path_length);
346}
347
348/***************************************************************************
349 Tell all smbd's to delete an entry.
350**************************************************************************/
351
352void send_stat_cache_delete_message(struct messaging_context *msg_ctx,
353 const char *name)
354{
355#ifdef DEVELOPER
356 message_send_all(msg_ctx,
357 MSG_SMB_STAT_CACHE_DELETE,
358 name,
359 strlen(name)+1,
360 NULL);
361#endif
362}
363
364/***************************************************************************
365 Delete an entry.
366**************************************************************************/
367
368void stat_cache_delete(const char *name)
369{
370 char *lname = talloc_strdup_upper(talloc_tos(), name);
371
372 if (!lname) {
373 return;
374 }
375 DEBUG(10,("stat_cache_delete: deleting name [%s] -> %s\n",
376 lname, name ));
377
378 memcache_delete(smbd_memcache(), STAT_CACHE,
379 data_blob_const(lname, talloc_get_size(lname)-1));
380 TALLOC_FREE(lname);
381}
382
383/***************************************************************
384 Compute a hash value based on a string key value.
385 The function returns the bucket index number for the hashed key.
386 JRA. Use a djb-algorithm hash for speed.
387***************************************************************/
388
389unsigned int fast_string_hash(struct TDB_DATA *key)
390{
391 unsigned int n = 0;
392 const char *p;
393 for (p = (const char *)key->dptr; *p != '\0'; p++) {
394 n = ((n << 5) + n) ^ (unsigned int)(*p);
395 }
396 return n;
397}
398
399/***************************************************************************
400 Initializes or clears the stat cache.
401**************************************************************************/
402
403bool reset_stat_cache( void )
404{
405 if (!lp_stat_cache())
406 return True;
407
408 memcache_flush(smbd_memcache(), STAT_CACHE);
409
410 return True;
411}
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