source: branches/samba-3.5.x/source3/smbd/statcache.c

Last change on this file was 732, checked in by Silvan Scherrer, 13 years ago

Samba Server 3.5: update branche to 3.5.12
File size: 10.5 KB
RevLine 
[732]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 posix_paths Whether to lookup using stat() or lstat()
149 * @param name The path we are attempting to cache, modified by this routine
150 * to be correct as far as the cache can tell us. We assume that
151 * it is a talloc'ed string from top of stack, we free it if
152 * necessary.
153 * @param dirpath The path as far as the stat cache told us. Also talloced
154 * from top of stack.
155 * @param start A pointer into name, for where to 'start' in fixing the rest
156 * of the name up.
157 * @param psd A stat buffer, NOT from the cache, but just a side-effect.
158 *
159 * @return True if we translated (and did a scuccessful stat on) the entire
160 * name.
161 *
162 */
163
164bool stat_cache_lookup(connection_struct *conn,
165 bool posix_paths,
166 char **pp_name,
167 char **pp_dirpath,
168 char **pp_start,
169 SMB_STRUCT_STAT *pst)
170{
171 char *chk_name;
172 size_t namelen;
173 bool sizechanged = False;
174 unsigned int num_components = 0;
175 char *translated_path;
176 size_t translated_path_length;
177 DATA_BLOB data_val;
178 char *name;
179 TALLOC_CTX *ctx = talloc_tos();
180 struct smb_filename smb_fname;
181 int ret;
182
183 *pp_dirpath = NULL;
184 *pp_start = *pp_name;
185
186 if (!lp_stat_cache()) {
187 return False;
188 }
189
190 name = *pp_name;
191 namelen = strlen(name);
192
193 DO_PROFILE_INC(statcache_lookups);
194
195 /*
196 * Don't lookup trivial valid directory entries.
197 */
198 if ((*name == '\0') || ISDOT(name) || ISDOTDOT(name)) {
199 return False;
200 }
201
202 if (conn->case_sensitive) {
203 chk_name = talloc_strdup(ctx,name);
204 if (!chk_name) {
205 DEBUG(0, ("stat_cache_lookup: strdup failed!\n"));
206 return False;
207 }
208
209 } else {
210 chk_name = talloc_strdup_upper(ctx,name);
211 if (!chk_name) {
212 DEBUG(0, ("stat_cache_lookup: talloc_strdup_upper failed!\n"));
213 return False;
214 }
215
216 /*
217 * In some language encodings the length changes
218 * if we uppercase. We need to treat this differently
219 * below.
220 */
221 if (strlen(chk_name) != namelen) {
222 sizechanged = True;
223 }
224 }
225
226 while (1) {
227 char *sp;
228
229 data_val = data_blob_null;
230
231 if (memcache_lookup(
232 smbd_memcache(), STAT_CACHE,
233 data_blob_const(chk_name, strlen(chk_name)),
234 &data_val)) {
235 break;
236 }
237
238 DEBUG(10,("stat_cache_lookup: lookup failed for name [%s]\n",
239 chk_name ));
240 /*
241 * Didn't find it - remove last component for next try.
242 */
243 if (!(sp = strrchr_m(chk_name, '/'))) {
244 /*
245 * We reached the end of the name - no match.
246 */
247 DO_PROFILE_INC(statcache_misses);
248 TALLOC_FREE(chk_name);
249 return False;
250 }
251
252 *sp = '\0';
253
254 /*
255 * Count the number of times we have done this, we'll
256 * need it when reconstructing the string.
257 */
258
259 if (sizechanged) {
260 num_components++;
261 }
262
263 if ((*chk_name == '\0')
264 || ISDOT(chk_name) || ISDOTDOT(chk_name)) {
265 DO_PROFILE_INC(statcache_misses);
266 TALLOC_FREE(chk_name);
267 return False;
268 }
269 }
270
271 translated_path = talloc_strdup(ctx,(char *)data_val.data);
272 if (!translated_path) {
273 smb_panic("talloc failed");
274 }
275 translated_path_length = data_val.length - 1;
276
277 DEBUG(10,("stat_cache_lookup: lookup succeeded for name [%s] "
278 "-> [%s]\n", chk_name, translated_path ));
279 DO_PROFILE_INC(statcache_hits);
280
281 ZERO_STRUCT(smb_fname);
282 smb_fname.base_name = translated_path;
283
284 if (posix_paths) {
285 ret = SMB_VFS_LSTAT(conn, &smb_fname);
286 } else {
287 ret = SMB_VFS_STAT(conn, &smb_fname);
288 }
289
290 if (ret != 0) {
291 /* Discard this entry - it doesn't exist in the filesystem. */
292 memcache_delete(smbd_memcache(), STAT_CACHE,
293 data_blob_const(chk_name, strlen(chk_name)));
294 TALLOC_FREE(chk_name);
295 TALLOC_FREE(translated_path);
296 return False;
297 }
298 *pst = smb_fname.st;
299
300 if (!sizechanged) {
301 memcpy(*pp_name, translated_path,
302 MIN(namelen, translated_path_length));
303 } else {
304 if (num_components == 0) {
305 name = talloc_strndup(ctx, translated_path,
306 translated_path_length);
307 } else {
308 char *sp;
309
310 sp = strnrchr_m(name, '/', num_components);
311 if (sp) {
312 name = talloc_asprintf(ctx,"%.*s%s",
313 (int)translated_path_length,
314 translated_path, sp);
315 } else {
316 name = talloc_strndup(ctx,
317 translated_path,
318 translated_path_length);
319 }
320 }
321 if (name == NULL) {
322 /*
323 * TODO: Get us out of here with a real error message
324 */
325 smb_panic("talloc failed");
326 }
327 TALLOC_FREE(*pp_name);
328 *pp_name = name;
329 }
330
331
332 /* set pointer for 'where to start' on fixing the rest of the name */
333 *pp_start = &name[translated_path_length];
334 if (**pp_start == '/') {
335 ++*pp_start;
336 }
337
338 *pp_dirpath = translated_path;
339 TALLOC_FREE(chk_name);
340 return (namelen == translated_path_length);
341}
342
343/***************************************************************************
344 Tell all smbd's to delete an entry.
345**************************************************************************/
346
347void send_stat_cache_delete_message(const char *name)
348{
349#ifdef DEVELOPER
350 message_send_all(smbd_messaging_context(),
351 MSG_SMB_STAT_CACHE_DELETE,
352 name,
353 strlen(name)+1,
354 NULL);
355#endif
356}
357
358/***************************************************************************
359 Delete an entry.
360**************************************************************************/
361
362void stat_cache_delete(const char *name)
363{
364 char *lname = talloc_strdup_upper(talloc_tos(), name);
365
366 if (!lname) {
367 return;
368 }
369 DEBUG(10,("stat_cache_delete: deleting name [%s] -> %s\n",
370 lname, name ));
371
372 memcache_delete(smbd_memcache(), STAT_CACHE,
373 data_blob_const(lname, talloc_get_size(lname)-1));
374 TALLOC_FREE(lname);
375}
376
377/***************************************************************
378 Compute a hash value based on a string key value.
379 The function returns the bucket index number for the hashed key.
380 JRA. Use a djb-algorithm hash for speed.
381***************************************************************/
382
383unsigned int fast_string_hash(TDB_DATA *key)
384{
385 unsigned int n = 0;
386 const char *p;
387 for (p = (const char *)key->dptr; *p != '\0'; p++) {
388 n = ((n << 5) + n) ^ (unsigned int)(*p);
389 }
390 return n;
391}
392
393/***************************************************************************
394 Initializes or clears the stat cache.
395**************************************************************************/
396
397bool reset_stat_cache( void )
398{
399 if (!lp_stat_cache())
400 return True;
401
402 memcache_flush(smbd_memcache(), STAT_CACHE);
403
404 return True;
405}
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