b0904c9ff719dd132e42f4a77d5c18279aaff4ec
[nivanova/samba-autobuild/.git] / source3 / smbd / statcache.c
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_compat.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
46 void 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 name    The path we are attempting to cache, modified by this routine
154  *                to be correct as far as the cache can tell us. We assume that
155  *                it is a talloc'ed string from top of stack, we free it if
156  *                necessary.
157  * @param dirpath The path as far as the stat cache told us. Also talloced
158  *                from top of stack.
159  * @param start   A pointer into name, for where to 'start' in fixing the rest
160  *                of the name up.
161  * @param psd     A stat buffer, NOT from the cache, but just a side-effect.
162  *
163  * @return True if we translated (and did a scuccessful stat on) the entire
164  *                name.
165  *
166  */
167
168 bool stat_cache_lookup(connection_struct *conn,
169                         char **pp_name,
170                         char **pp_dirpath,
171                         char **pp_start,
172                         SMB_STRUCT_STAT *pst)
173 {
174         char *chk_name;
175         size_t namelen;
176         bool sizechanged = False;
177         unsigned int num_components = 0;
178         char *translated_path;
179         size_t translated_path_length;
180         DATA_BLOB data_val;
181         char *name;
182         TALLOC_CTX *ctx = talloc_tos();
183         struct smb_filename smb_fname;
184
185         *pp_dirpath = NULL;
186         *pp_start = *pp_name;
187
188         if (!lp_stat_cache()) {
189                 return False;
190         }
191
192         name = *pp_name;
193         namelen = strlen(name);
194
195         DO_PROFILE_INC(statcache_lookups);
196
197         /*
198          * Don't lookup trivial valid directory entries.
199          */
200         if ((*name == '\0') || ISDOT(name) || ISDOTDOT(name)) {
201                 return False;
202         }
203
204         if (conn->case_sensitive) {
205                 chk_name = talloc_strdup(ctx,name);
206                 if (!chk_name) {
207                         DEBUG(0, ("stat_cache_lookup: strdup failed!\n"));
208                         return False;
209                 }
210
211         } else {
212                 chk_name = talloc_strdup_upper(ctx,name);
213                 if (!chk_name) {
214                         DEBUG(0, ("stat_cache_lookup: talloc_strdup_upper failed!\n"));
215                         return False;
216                 }
217
218                 /*
219                  * In some language encodings the length changes
220                  * if we uppercase. We need to treat this differently
221                  * below.
222                  */
223                 if (strlen(chk_name) != namelen) {
224                         sizechanged = True;
225                 }
226         }
227
228         while (1) {
229                 char *sp;
230
231                 data_val = data_blob_null;
232
233                 if (memcache_lookup(
234                             smbd_memcache(), STAT_CACHE,
235                             data_blob_const(chk_name, strlen(chk_name)),
236                             &data_val)) {
237                         break;
238                 }
239
240                 DEBUG(10,("stat_cache_lookup: lookup failed for name [%s]\n",
241                                 chk_name ));
242                 /*
243                  * Didn't find it - remove last component for next try.
244                  */
245                 if (!(sp = strrchr_m(chk_name, '/'))) {
246                         /*
247                          * We reached the end of the name - no match.
248                          */
249                         DO_PROFILE_INC(statcache_misses);
250                         TALLOC_FREE(chk_name);
251                         return False;
252                 }
253
254                 *sp = '\0';
255
256                 /*
257                  * Count the number of times we have done this, we'll
258                  * need it when reconstructing the string.
259                  */
260
261                 if (sizechanged) {
262                         num_components++;
263                 }
264
265                 if ((*chk_name == '\0')
266                     || ISDOT(chk_name) || ISDOTDOT(chk_name)) {
267                         DO_PROFILE_INC(statcache_misses);
268                         TALLOC_FREE(chk_name);
269                         return False;
270                 }
271         }
272
273         translated_path = talloc_strdup(ctx,(char *)data_val.data);
274         if (!translated_path) {
275                 smb_panic("talloc failed");
276         }
277         translated_path_length = data_val.length - 1;
278
279         DEBUG(10,("stat_cache_lookup: lookup succeeded for name [%s] "
280                   "-> [%s]\n", chk_name, translated_path ));
281         DO_PROFILE_INC(statcache_hits);
282
283         ZERO_STRUCT(smb_fname);
284         smb_fname.base_name = translated_path;
285
286         if (SMB_VFS_STAT(conn, &smb_fname) != 0) {
287                 /* Discard this entry - it doesn't exist in the filesystem. */
288                 memcache_delete(smbd_memcache(), STAT_CACHE,
289                                 data_blob_const(chk_name, strlen(chk_name)));
290                 TALLOC_FREE(chk_name);
291                 TALLOC_FREE(translated_path);
292                 return False;
293         }
294         *pst = smb_fname.st;
295
296         if (!sizechanged) {
297                 memcpy(*pp_name, translated_path,
298                        MIN(namelen, translated_path_length));
299         } else {
300                 if (num_components == 0) {
301                         name = talloc_strndup(ctx, translated_path,
302                                            translated_path_length);
303                 } else {
304                         char *sp;
305
306                         sp = strnrchr_m(name, '/', num_components);
307                         if (sp) {
308                                 name = talloc_asprintf(ctx,"%.*s%s",
309                                          (int)translated_path_length,
310                                          translated_path, sp);
311                         } else {
312                                 name = talloc_strndup(ctx,
313                                                 translated_path,
314                                                 translated_path_length);
315                         }
316                 }
317                 if (name == NULL) {
318                         /*
319                          * TODO: Get us out of here with a real error message
320                          */
321                         smb_panic("talloc failed");
322                 }
323                 TALLOC_FREE(*pp_name);
324                 *pp_name = name;
325         }
326
327
328         /* set pointer for 'where to start' on fixing the rest of the name */
329         *pp_start = &name[translated_path_length];
330         if (**pp_start == '/') {
331                 ++*pp_start;
332         }
333
334         *pp_dirpath = translated_path;
335         TALLOC_FREE(chk_name);
336         return (namelen == translated_path_length);
337 }
338
339 /***************************************************************************
340  Tell all smbd's to delete an entry.
341 **************************************************************************/
342
343 void send_stat_cache_delete_message(struct messaging_context *msg_ctx,
344                                     const char *name)
345 {
346 #ifdef DEVELOPER
347         message_send_all(msg_ctx,
348                         MSG_SMB_STAT_CACHE_DELETE,
349                         name,
350                         strlen(name)+1,
351                         NULL);
352 #endif
353 }
354
355 /***************************************************************************
356  Delete an entry.
357 **************************************************************************/
358
359 void stat_cache_delete(const char *name)
360 {
361         char *lname = talloc_strdup_upper(talloc_tos(), name);
362
363         if (!lname) {
364                 return;
365         }
366         DEBUG(10,("stat_cache_delete: deleting name [%s] -> %s\n",
367                         lname, name ));
368
369         memcache_delete(smbd_memcache(), STAT_CACHE,
370                         data_blob_const(lname, talloc_get_size(lname)-1));
371         TALLOC_FREE(lname);
372 }
373
374 /***************************************************************
375  Compute a hash value based on a string key value.
376  The function returns the bucket index number for the hashed key.
377  JRA. Use a djb-algorithm hash for speed.
378 ***************************************************************/
379
380 unsigned int fast_string_hash(TDB_DATA *key)
381 {
382         unsigned int n = 0;
383         const char *p;
384         for (p = (const char *)key->dptr; *p != '\0'; p++) {
385                 n = ((n << 5) + n) ^ (unsigned int)(*p);
386         }
387         return n;
388 }
389
390 /***************************************************************************
391  Initializes or clears the stat cache.
392 **************************************************************************/
393
394 bool reset_stat_cache( void )
395 {
396         if (!lp_stat_cache())
397                 return True;
398
399         memcache_flush(smbd_memcache(), STAT_CACHE);
400
401         return True;
402 }