source: branches/samba-3.5.x/source3/smbd/statcache.c@ 717

Last change on this file since 717 was 414, checked in by Herwig Bauernfeind, 15 years ago

Samba 3.5.0: Initial import
File size: 9.9 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 struct smb_filename smb_fname;
179
180 *pp_dirpath = NULL;
181 *pp_start = *pp_name;
182
183 if (!lp_stat_cache()) {
184 return False;
185 }
186
187 name = *pp_name;
188 namelen = strlen(name);
189
190 DO_PROFILE_INC(statcache_lookups);
191
192 /*
193 * Don't lookup trivial valid directory entries.
194 */
195 if ((*name == '\0') || ISDOT(name) || ISDOTDOT(name)) {
196 return False;
197 }
198
199 if (conn->case_sensitive) {
200 chk_name = talloc_strdup(ctx,name);
201 if (!chk_name) {
202 DEBUG(0, ("stat_cache_lookup: strdup failed!\n"));
203 return False;
204 }
205
206 } else {
207 chk_name = talloc_strdup_upper(ctx,name);
208 if (!chk_name) {
209 DEBUG(0, ("stat_cache_lookup: talloc_strdup_upper failed!\n"));
210 return False;
211 }
212
213 /*
214 * In some language encodings the length changes
215 * if we uppercase. We need to treat this differently
216 * below.
217 */
218 if (strlen(chk_name) != namelen) {
219 sizechanged = True;
220 }
221 }
222
223 while (1) {
224 char *sp;
225
226 data_val = data_blob_null;
227
228 if (memcache_lookup(
229 smbd_memcache(), STAT_CACHE,
230 data_blob_const(chk_name, strlen(chk_name)),
231 &data_val)) {
232 break;
233 }
234
235 DEBUG(10,("stat_cache_lookup: lookup failed for name [%s]\n",
236 chk_name ));
237 /*
238 * Didn't find it - remove last component for next try.
239 */
240 if (!(sp = strrchr_m(chk_name, '/'))) {
241 /*
242 * We reached the end of the name - no match.
243 */
244 DO_PROFILE_INC(statcache_misses);
245 TALLOC_FREE(chk_name);
246 return False;
247 }
248
249 *sp = '\0';
250
251 /*
252 * Count the number of times we have done this, we'll
253 * need it when reconstructing the string.
254 */
255
256 if (sizechanged) {
257 num_components++;
258 }
259
260 if ((*chk_name == '\0')
261 || ISDOT(chk_name) || ISDOTDOT(chk_name)) {
262 DO_PROFILE_INC(statcache_misses);
263 TALLOC_FREE(chk_name);
264 return False;
265 }
266 }
267
268 translated_path = talloc_strdup(ctx,(char *)data_val.data);
269 if (!translated_path) {
270 smb_panic("talloc failed");
271 }
272 translated_path_length = data_val.length - 1;
273
274 DEBUG(10,("stat_cache_lookup: lookup succeeded for name [%s] "
275 "-> [%s]\n", chk_name, translated_path ));
276 DO_PROFILE_INC(statcache_hits);
277
278 ZERO_STRUCT(smb_fname);
279 smb_fname.base_name = translated_path;
280
281 if (SMB_VFS_STAT(conn, &smb_fname) != 0) {
282 /* Discard this entry - it doesn't exist in the filesystem. */
283 memcache_delete(smbd_memcache(), STAT_CACHE,
284 data_blob_const(chk_name, strlen(chk_name)));
285 TALLOC_FREE(chk_name);
286 TALLOC_FREE(translated_path);
287 return False;
288 }
289 *pst = smb_fname.st;
290
291 if (!sizechanged) {
292 memcpy(*pp_name, translated_path,
293 MIN(namelen, translated_path_length));
294 } else {
295 if (num_components == 0) {
296 name = talloc_strndup(ctx, translated_path,
297 translated_path_length);
298 } else {
299 char *sp;
300
301 sp = strnrchr_m(name, '/', num_components);
302 if (sp) {
303 name = talloc_asprintf(ctx,"%.*s%s",
304 (int)translated_path_length,
305 translated_path, sp);
306 } else {
307 name = talloc_strndup(ctx,
308 translated_path,
309 translated_path_length);
310 }
311 }
312 if (name == NULL) {
313 /*
314 * TODO: Get us out of here with a real error message
315 */
316 smb_panic("talloc failed");
317 }
318 TALLOC_FREE(*pp_name);
319 *pp_name = name;
320 }
321
322
323 /* set pointer for 'where to start' on fixing the rest of the name */
324 *pp_start = &name[translated_path_length];
325 if (**pp_start == '/') {
326 ++*pp_start;
327 }
328
329 *pp_dirpath = translated_path;
330 TALLOC_FREE(chk_name);
331 return (namelen == translated_path_length);
332}
333
334/***************************************************************************
335 Tell all smbd's to delete an entry.
336**************************************************************************/
337
338void send_stat_cache_delete_message(const char *name)
339{
340#ifdef DEVELOPER
341 message_send_all(smbd_messaging_context(),
342 MSG_SMB_STAT_CACHE_DELETE,
343 name,
344 strlen(name)+1,
345 NULL);
346#endif
347}
348
349/***************************************************************************
350 Delete an entry.
351**************************************************************************/
352
353void stat_cache_delete(const char *name)
354{
355 char *lname = talloc_strdup_upper(talloc_tos(), name);
356
357 if (!lname) {
358 return;
359 }
360 DEBUG(10,("stat_cache_delete: deleting name [%s] -> %s\n",
361 lname, name ));
362
363 memcache_delete(smbd_memcache(), STAT_CACHE,
364 data_blob_const(lname, talloc_get_size(lname)-1));
365 TALLOC_FREE(lname);
366}
367
368/***************************************************************
369 Compute a hash value based on a string key value.
370 The function returns the bucket index number for the hashed key.
371 JRA. Use a djb-algorithm hash for speed.
372***************************************************************/
373
374unsigned int fast_string_hash(TDB_DATA *key)
375{
376 unsigned int n = 0;
377 const char *p;
378 for (p = (const char *)key->dptr; *p != '\0'; p++) {
379 n = ((n << 5) + n) ^ (unsigned int)(*p);
380 }
381 return n;
382}
383
384/***************************************************************************
385 Initializes or clears the stat cache.
386**************************************************************************/
387
388bool reset_stat_cache( void )
389{
390 if (!lp_stat_cache())
391 return True;
392
393 memcache_flush(smbd_memcache(), STAT_CACHE);
394
395 return True;
396}
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