summaryrefslogtreecommitdiff
path: root/source3/smbd/statcache.c
blob: dfc1a6ed9595f3606bd61a552d27856420bbaebf (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
/* 
   Unix SMB/CIFS implementation.
   stat cache code
   Copyright (C) Andrew Tridgell 1992-2000
   Copyright (C) Jeremy Allison 1999-2004
   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2003
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "includes.h"

/****************************************************************************
 Stat cache code used in unix_convert.
*****************************************************************************/

static TDB_CONTEXT *tdb_stat_cache;

/**
 * Add an entry into the stat cache.
 *
 * @param full_orig_name       The original name as specified by the client
 * @param orig_translated_path The name on our filesystem.
 * 
 * @note Only the first strlen(orig_translated_path) characters are stored 
 *       into the cache.  This means that full_orig_name will be internally
 *       truncated.
 *
 */

void stat_cache_add( const char *full_orig_name, const char *orig_translated_path, BOOL case_sensitive)
{
	char *translated_path;
	size_t translated_path_length;
	TDB_DATA data_val;
	char *original_path;
	size_t original_path_length;

	if (!lp_stat_cache())
		return;

	ZERO_STRUCT(data_val);

	/*
	 * Don't cache trivial valid directory entries such as . and ..
	 */

	if((*full_orig_name == '\0') || (full_orig_name[0] == '.' && 
				((full_orig_name[1] == '\0') ||
				 (full_orig_name[1] == '.' && full_orig_name[1] == '\0'))))
		return;

	/*
	 * If we are in case insentive mode, we don't need to
	 * store names that need no translation - else, it
	 * would be a waste.
	 */

	if(case_sensitive && (strcmp(full_orig_name, orig_translated_path) == 0))
		return;

	/*
	 * Remove any trailing '/' characters from the
	 * translated path.
	 */

	translated_path = strdup(orig_translated_path);
	if (!translated_path)
		return;

	translated_path_length = strlen(translated_path);

	if(translated_path[translated_path_length-1] == '/') {
		translated_path[translated_path_length-1] = '\0';
		translated_path_length--;
	}

	if(case_sensitive) {
		original_path = strdup(full_orig_name);
	} else {
		original_path = strdup_upper(full_orig_name);
	}

	if (!original_path) {
		SAFE_FREE(translated_path);
		return;
	}

	original_path_length = strlen(original_path);

	if(original_path[original_path_length-1] == '/') {
		original_path[original_path_length-1] = '\0';
		original_path_length--;
	}

	if (original_path_length != translated_path_length) {
		if (original_path_length < translated_path_length) {
			DEBUG(0, ("OOPS - tried to store stat cache entry for weird length paths [%s] %lu and [%s] %lu)!\n",
				  original_path, (unsigned long)original_path_length, translated_path, (unsigned long)translated_path_length));
			SAFE_FREE(original_path);
			SAFE_FREE(translated_path);
			return;
		}

		/* we only want to index by the first part of original_path,
			up to the length of translated_path */

		original_path[translated_path_length] = '\0';
		original_path_length = translated_path_length;
	}

	/*
	 * New entry or replace old entry.
	 */
  
	data_val.dsize = translated_path_length + 1;
	data_val.dptr = translated_path;

	if (tdb_store_bystring(tdb_stat_cache, original_path, data_val, TDB_REPLACE) != 0) {
		DEBUG(0,("stat_cache_add: Error storing entry %s -> %s\n", original_path, translated_path));
	} else {
		DEBUG(5,("stat_cache_add: Added entry (%x:size%x) %s -> %s\n",
			(unsigned int)data_val.dptr, data_val.dsize, original_path, translated_path));
	}

	SAFE_FREE(original_path);
	SAFE_FREE(translated_path);
}

/**
 * Look through the stat cache for an entry
 *
 * @param conn    A connection struct to do the stat() with.
 * @param name    The path we are attempting to cache, modified by this routine
 *                to be correct as far as the cache can tell us
 * @param dirpath The path as far as the stat cache told us.
 * @param start   A pointer into name, for where to 'start' in fixing the rest of the name up.
 * @param psd     A stat buffer, NOT from the cache, but just a side-effect.
 *
 * @return True if we translated (and did a scuccessful stat on) the entire name.
 *
 */

BOOL stat_cache_lookup(connection_struct *conn, pstring name, pstring dirpath, 
		       char **start, SMB_STRUCT_STAT *pst)
{
	char *chk_name;
	size_t namelen;
	BOOL sizechanged = False;
	unsigned int num_components = 0;

	if (!lp_stat_cache())
		return False;
 
	namelen = strlen(name);

	*start = name;

	DO_PROFILE_INC(statcache_lookups);

	/*
	 * Don't lookup trivial valid directory entries.
	 */
	if((*name == '\0') || (name[0] == '.' && 
				((name[1] == '\0') ||
				 (name[1] == '.' && name[1] == '\0'))))
		return False;

	if (conn->case_sensitive) {
		chk_name = strdup(name);
		if (!chk_name) {
			DEBUG(0, ("stat_cache_lookup: strdup failed!\n"));
			return False;
		}

	} else {
		chk_name = strdup_upper(name);
		if (!chk_name) {
			DEBUG(0, ("stat_cache_lookup: strdup_upper failed!\n"));
			return False;
		}

		/*
		 * In some language encodings the length changes
		 * if we uppercase. We need to treat this differently
		 * below.
		 */
		if (strlen(chk_name) != namelen)
			sizechanged = True;
	}

	while (1) {
		TDB_DATA data_val;
		char *sp;

		data_val = tdb_fetch_bystring(tdb_stat_cache, chk_name);
		if(data_val.dptr == NULL || data_val.dsize == 0) {
			DEBUG(10,("stat_cache_lookup: lookup failed for name [%s]\n", chk_name ));
			/*
			 * Didn't find it - remove last component for next try.
			 */
			sp = strrchr_m(chk_name, '/');
			if (sp) {
				*sp = '\0';
				/*
				 * Count the number of times we have done this,
				 * we'll need it when reconstructing the string.
				 */
				if (sizechanged)
					num_components++;

			} else {
				/*
				 * We reached the end of the name - no match.
				 */
				DO_PROFILE_INC(statcache_misses);
				SAFE_FREE(chk_name);
				return False;
			}
			if((*chk_name == '\0') || (strcmp(chk_name, ".") == 0)
					|| (strcmp(chk_name, "..") == 0)) {
				DO_PROFILE_INC(statcache_misses);
				SAFE_FREE(chk_name);
				return False;
			}
		} else {
			BOOL retval;
			char *translated_path = data_val.dptr;
			size_t translated_path_length = data_val.dsize - 1;

			DEBUG(10,("stat_cache_lookup: lookup succeeded for name [%s] -> [%s]\n", chk_name, translated_path ));
			DO_PROFILE_INC(statcache_hits);
			if(SMB_VFS_STAT(conn,translated_path, pst) != 0) {
				/* Discard this entry - it doesn't exist in the filesystem.  */
				tdb_delete_bystring(tdb_stat_cache, chk_name);
				SAFE_FREE(chk_name);
				SAFE_FREE(data_val.dptr);
				return False;
			}

			if (!sizechanged) {
				memcpy(name, translated_path, MIN(sizeof(pstring)-1, translated_path_length));
			} else if (num_components == 0) {
				pstrcpy(name, translated_path);
			} else {
				sp = strnrchr_m(name, '/', num_components);
				if (sp) {
					pstring last_component;
					pstrcpy(last_component, sp);
					pstrcpy(name, translated_path);
					pstrcat(name, last_component);
				} else {
					pstrcpy(name, translated_path);
				}
			}

			/* set pointer for 'where to start' on fixing the rest of the name */
			*start = &name[translated_path_length];
			if(**start == '/')
				++*start;

			pstrcpy(dirpath, translated_path);
			retval = (namelen == translated_path_length) ? True : False;
			SAFE_FREE(chk_name);
			SAFE_FREE(data_val.dptr);
			return retval;
		}
	}
}

/***************************************************************
 Compute a hash value based on a string key value.
 The function returns the bucket index number for the hashed key.
 JRA. Use a djb-algorithm hash for speed.
***************************************************************/
                                                                                                     
static u32 string_hash(TDB_DATA *key)
{
        u32 n = 0;
        const char *p;
        for (p = key->dptr; *p != '\0'; p++) {
                n = ((n << 5) + n) ^ (u32)(*p);
        }
        return n;
}

/***************************************************************************
 Initializes or clears the stat cache.
**************************************************************************/

BOOL reset_stat_cache( void )
{
	if (!lp_stat_cache())
		return True;

	if (tdb_stat_cache) {
		tdb_close(tdb_stat_cache);
	}

	/* Create the in-memory tdb using our custom hash function. */
	tdb_stat_cache = tdb_open_ex("statcache", 0, TDB_INTERNAL,
                                    (O_RDWR|O_CREAT), 0644, NULL, string_hash);

	if (!tdb_stat_cache)
		return False;
	return True;
}