1/*
2   Unix SMB/CIFS implementation.
3   stat cache code
4   Copyright (C) Andrew Tridgell 1992-2000
5   Copyright (C) Jeremy Allison 1999-2004
6   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2003
7
8   This program is free software; you can redistribute it and/or modify
9   it under the terms of the GNU General Public License as published by
10   the Free Software Foundation; either version 2 of the License, or
11   (at your option) any later version.
12
13   This program is distributed in the hope that it will be useful,
14   but WITHOUT ANY WARRANTY; without even the implied warranty of
15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16   GNU General Public License for more details.
17
18   You should have received a copy of the GNU General Public License
19   along with this program; if not, write to the Free Software
20   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21*/
22
23#include "includes.h"
24
25/****************************************************************************
26 Stat cache code used in unix_convert.
27*****************************************************************************/
28
29static TDB_CONTEXT *tdb_stat_cache;
30
31/**
32 * Add an entry into the stat cache.
33 *
34 * @param full_orig_name       The original name as specified by the client
35 * @param orig_translated_path The name on our filesystem.
36 *
37 * @note Only the first strlen(orig_translated_path) characters are stored
38 *       into the cache.  This means that full_orig_name will be internally
39 *       truncated.
40 *
41 */
42
43void stat_cache_add( const char *full_orig_name, const char *orig_translated_path, BOOL case_sensitive)
44{
45	char *translated_path;
46	size_t translated_path_length;
47	TDB_DATA data_val;
48	char *original_path;
49	size_t original_path_length;
50
51	if (!lp_stat_cache())
52		return;
53
54	ZERO_STRUCT(data_val);
55
56	/*
57	 * Don't cache trivial valid directory entries such as . and ..
58	 */
59
60	if((*full_orig_name == '\0') || (full_orig_name[0] == '.' &&
61				((full_orig_name[1] == '\0') ||
62				 (full_orig_name[1] == '.' && full_orig_name[1] == '\0'))))
63		return;
64
65	/*
66	 * If we are in case insentive mode, we don't need to
67	 * store names that need no translation - else, it
68	 * would be a waste.
69	 */
70
71	if(case_sensitive && (strcmp(full_orig_name, orig_translated_path) == 0))
72		return;
73
74	/*
75	 * Remove any trailing '/' characters from the
76	 * translated path.
77	 */
78
79	translated_path = SMB_STRDUP(orig_translated_path);
80	if (!translated_path)
81		return;
82
83	translated_path_length = strlen(translated_path);
84
85	if(translated_path[translated_path_length-1] == '/') {
86		translated_path[translated_path_length-1] = '\0';
87		translated_path_length--;
88	}
89
90	if(case_sensitive) {
91		original_path = SMB_STRDUP(full_orig_name);
92	} else {
93		original_path = strdup_upper(full_orig_name);
94	}
95
96	if (!original_path) {
97		SAFE_FREE(translated_path);
98		return;
99	}
100
101	original_path_length = strlen(original_path);
102
103	if(original_path[original_path_length-1] == '/') {
104		original_path[original_path_length-1] = '\0';
105		original_path_length--;
106	}
107
108	if (original_path_length != translated_path_length) {
109		if (original_path_length < translated_path_length) {
110			DEBUG(0, ("OOPS - tried to store stat cache entry for weird length paths [%s] %lu and [%s] %lu)!\n",
111				  original_path, (unsigned long)original_path_length, translated_path, (unsigned long)translated_path_length));
112			SAFE_FREE(original_path);
113			SAFE_FREE(translated_path);
114			return;
115		}
116
117		/* we only want to index by the first part of original_path,
118			up to the length of translated_path */
119
120		original_path[translated_path_length] = '\0';
121		original_path_length = translated_path_length;
122	}
123
124	/*
125	 * New entry or replace old entry.
126	 */
127
128	data_val.dsize = translated_path_length + 1;
129	data_val.dptr = translated_path;
130
131	if (tdb_store_bystring(tdb_stat_cache, original_path, data_val, TDB_REPLACE) != 0) {
132		DEBUG(0,("stat_cache_add: Error storing entry %s -> %s\n", original_path, translated_path));
133	} else {
134		DEBUG(5,("stat_cache_add: Added entry (%x:size%x) %s -> %s\n",
135			(unsigned int)data_val.dptr, data_val.dsize, original_path, translated_path));
136	}
137
138	SAFE_FREE(original_path);
139	SAFE_FREE(translated_path);
140}
141
142/**
143 * Look through the stat cache for an entry
144 *
145 * @param conn    A connection struct to do the stat() with.
146 * @param name    The path we are attempting to cache, modified by this routine
147 *                to be correct as far as the cache can tell us
148 * @param dirpath The path as far as the stat cache told us.
149 * @param start   A pointer into name, for where to 'start' in fixing the rest of the name up.
150 * @param psd     A stat buffer, NOT from the cache, but just a side-effect.
151 *
152 * @return True if we translated (and did a scuccessful stat on) the entire name.
153 *
154 */
155
156BOOL stat_cache_lookup(connection_struct *conn, pstring name, pstring dirpath,
157		       char **start, SMB_STRUCT_STAT *pst)
158{
159	char *chk_name;
160	size_t namelen;
161	BOOL sizechanged = False;
162	unsigned int num_components = 0;
163
164	if (!lp_stat_cache())
165		return False;
166
167	namelen = strlen(name);
168
169	*start = name;
170
171	DO_PROFILE_INC(statcache_lookups);
172
173	/*
174	 * Don't lookup trivial valid directory entries.
175	 */
176	if((*name == '\0') || (name[0] == '.' &&
177				((name[1] == '\0') ||
178				 (name[1] == '.' && name[1] == '\0'))))
179		return False;
180
181	if (conn->case_sensitive) {
182		chk_name = SMB_STRDUP(name);
183		if (!chk_name) {
184			DEBUG(0, ("stat_cache_lookup: strdup failed!\n"));
185			return False;
186		}
187
188	} else {
189		chk_name = strdup_upper(name);
190		if (!chk_name) {
191			DEBUG(0, ("stat_cache_lookup: strdup_upper failed!\n"));
192			return False;
193		}
194
195		/*
196		 * In some language encodings the length changes
197		 * if we uppercase. We need to treat this differently
198		 * below.
199		 */
200		if (strlen(chk_name) != namelen)
201			sizechanged = True;
202	}
203
204	while (1) {
205		TDB_DATA data_val;
206		char *sp;
207
208		data_val = tdb_fetch_bystring(tdb_stat_cache, chk_name);
209		if(data_val.dptr == NULL || data_val.dsize == 0) {
210			DEBUG(10,("stat_cache_lookup: lookup failed for name [%s]\n", chk_name ));
211			/*
212			 * Didn't find it - remove last component for next try.
213			 */
214			sp = strrchr_m(chk_name, '/');
215			if (sp) {
216				*sp = '\0';
217				/*
218				 * Count the number of times we have done this,
219				 * we'll need it when reconstructing the string.
220				 */
221				if (sizechanged)
222					num_components++;
223
224			} else {
225				/*
226				 * We reached the end of the name - no match.
227				 */
228				DO_PROFILE_INC(statcache_misses);
229				SAFE_FREE(chk_name);
230				return False;
231			}
232			if((*chk_name == '\0') || (strcmp(chk_name, ".") == 0)
233					|| (strcmp(chk_name, "..") == 0)) {
234				DO_PROFILE_INC(statcache_misses);
235				SAFE_FREE(chk_name);
236				return False;
237			}
238		} else {
239			BOOL retval;
240			char *translated_path = data_val.dptr;
241			size_t translated_path_length = data_val.dsize - 1;
242
243			DEBUG(10,("stat_cache_lookup: lookup succeeded for name [%s] -> [%s]\n", chk_name, translated_path ));
244			DO_PROFILE_INC(statcache_hits);
245			if(SMB_VFS_STAT(conn,translated_path, pst) != 0) {
246				/* Discard this entry - it doesn't exist in the filesystem.  */
247				tdb_delete_bystring(tdb_stat_cache, chk_name);
248				SAFE_FREE(chk_name);
249				SAFE_FREE(data_val.dptr);
250				return False;
251			}
252
253			if (!sizechanged) {
254				memcpy(name, translated_path, MIN(sizeof(pstring)-1, translated_path_length));
255			} else if (num_components == 0) {
256				pstrcpy(name, translated_path);
257			} else {
258				sp = strnrchr_m(name, '/', num_components);
259				if (sp) {
260					pstring last_component;
261					pstrcpy(last_component, sp);
262					pstrcpy(name, translated_path);
263					pstrcat(name, last_component);
264				} else {
265					pstrcpy(name, translated_path);
266				}
267			}
268
269			/* set pointer for 'where to start' on fixing the rest of the name */
270			*start = &name[translated_path_length];
271			if(**start == '/')
272				++*start;
273
274			pstrcpy(dirpath, translated_path);
275			retval = (namelen == translated_path_length) ? True : False;
276			SAFE_FREE(chk_name);
277			SAFE_FREE(data_val.dptr);
278			return retval;
279		}
280	}
281}
282
283/***************************************************************
284 Compute a hash value based on a string key value.
285 The function returns the bucket index number for the hashed key.
286 JRA. Use a djb-algorithm hash for speed.
287***************************************************************/
288
289u32 fast_string_hash(TDB_DATA *key)
290{
291        u32 n = 0;
292        const char *p;
293        for (p = key->dptr; *p != '\0'; p++) {
294                n = ((n << 5) + n) ^ (u32)(*p);
295        }
296        return n;
297}
298
299/***************************************************************************
300 Initializes or clears the stat cache.
301**************************************************************************/
302
303BOOL reset_stat_cache( void )
304{
305	if (!lp_stat_cache())
306		return True;
307
308	if (tdb_stat_cache) {
309		tdb_close(tdb_stat_cache);
310	}
311
312	/* Create the in-memory tdb using our custom hash function. */
313	tdb_stat_cache = tdb_open_ex("statcache", 1031, TDB_INTERNAL,
314                                    (O_RDWR|O_CREAT), 0644, NULL, fast_string_hash);
315
316	if (!tdb_stat_cache)
317		return False;
318	return True;
319}
320