summaryrefslogtreecommitdiff
path: root/source3/smbd/files.c
blob: 7bd5501de532b9cdd96e6b5bd07cc58bd18e63e2 (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
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
/* 
   Unix SMB/Netbios implementation.
   Version 1.9.
   Files[] structure handling
   Copyright (C) Andrew Tridgell 1998
   
   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"

extern int DEBUGLEVEL;

/* the only restriction is that this must be less than PIPE_HANDLE_OFFSET */
#define MAX_FNUMS 4096

#define VALID_FNUM(fnum)   (((fnum) >= 0) && ((fnum) < MAX_FNUMS))

#define FILE_HANDLE_OFFSET 0x1000

static struct bitmap *file_bmap;
static struct bitmap *fd_bmap;

static files_struct *Files;

/* a fsp to use when chaining */
static files_struct *chain_fsp = NULL;


/*
 * Indirection for file fd's. Needed as POSIX locking
 * is based on file/process, not fd/process.
 */
static file_fd_struct *FileFd;

static int files_used, fd_ptr_used;

/****************************************************************************
  find first available file slot
****************************************************************************/
files_struct *file_new(void )
{
	int i;
	static int first_file;
	files_struct *fsp, *next;

	/* we want to give out file handles differently on each new
	   connection because of a common bug in MS clients where they try to
	   reuse a file descriptor from an earlier smb connection. This code
	   increases the chance that the errant client will get an error rather
	   than causing corruption */
	if (first_file == 0) {
		first_file = (getpid() ^ (int)time(NULL)) % MAX_FNUMS;
	}

	i = bitmap_find(file_bmap, first_file);
	if (i == -1) {
		/* 
		 * Before we give up, go through the open files 
		 * and see if there are any files opened with a
		 * batch oplock. If so break the oplock and then
		 * re-use that entry (if it becomes closed).
		 * This may help as NT/95 clients tend to keep
		 * files batch oplocked for quite a long time
		 * after they have finished with them.
		 */
		for (fsp=Files;fsp;fsp=next) {
			next=fsp->next;
			if (attempt_close_oplocked_file(fsp)) {
				return file_new();
			}
		}

		DEBUG(0,("ERROR! Out of file structures\n"));
		return NULL;
	}

	fsp = (files_struct *)malloc(sizeof(*fsp));
	if (!fsp) return NULL;

	memset(fsp, 0, sizeof(*fsp));

	first_file = (i+1) % MAX_FNUMS;

	bitmap_set(file_bmap, i);
	files_used++;

	fsp->fnum = i + FILE_HANDLE_OFFSET;
	string_init(&fsp->fsp_name,"");
	
	/* hook into the front of the list */
	if (!Files) {
		Files = fsp;
	} else {
		Files->prev = fsp;
		fsp->next = Files;
		Files = fsp;
	}

	DEBUG(5,("allocated file structure %d (%d used)\n",
		 i, files_used));

	chain_fsp = fsp;
	
	return fsp;
}



/****************************************************************************
fd support routines - attempt to find an already open file by dev
and inode - increments the ref_count of the returned file_fd_struct *.
****************************************************************************/
file_fd_struct *fd_get_already_open(struct stat *sbuf)
{
	file_fd_struct *fd_ptr;

	if(!sbuf) return NULL;

	for (fd_ptr=FileFd;fd_ptr;fd_ptr=fd_ptr->next) {
		if ((fd_ptr->ref_count > 0) &&
		    (((uint32)sbuf->st_dev) == fd_ptr->dev) &&
		    (((uint32)sbuf->st_ino) == fd_ptr->inode)) {
			fd_ptr->ref_count++;
			DEBUG(3,("Re-used file_fd_struct dev = %x, inode = %x, ref_count = %d\n",
				 fd_ptr->dev, fd_ptr->inode, 
				 fd_ptr->ref_count));
			return fd_ptr;
		}
	}

	return NULL;
}



/****************************************************************************
fd support routines - attempt to find a empty slot in the FileFd array.
Increments the ref_count of the returned entry.
****************************************************************************/
file_fd_struct *fd_get_new(void)
{
	extern struct current_user current_user;
	int i;
	file_fd_struct *fd_ptr;

	i = bitmap_find(fd_bmap, 1);
	if (i == -1) {
		DEBUG(0,("ERROR! Out of file_fd structures\n"));
		return NULL;
	}

	fd_ptr = (file_fd_struct *)malloc(sizeof(*fd_ptr));
	if (!fd_ptr) return NULL;
	
	memset(fd_ptr, 0, sizeof(*fd_ptr));
	
	fd_ptr->fdnum = i;
	fd_ptr->dev = (uint32)-1;
	fd_ptr->inode = (uint32)-1;
	fd_ptr->fd = -1;
	fd_ptr->fd_readonly = -1;
	fd_ptr->fd_writeonly = -1;
	fd_ptr->real_open_flags = -1;
	fd_add_to_uid_cache(fd_ptr, (uid_t)current_user.uid);
	fd_ptr->ref_count++;

	bitmap_set(fd_bmap, i);
	fd_ptr_used++;

	/* hook into the front of the list */
	if (!FileFd) {
		FileFd = fd_ptr;
	} else {
		FileFd->prev = fd_ptr;
		fd_ptr->next = FileFd;
		FileFd = fd_ptr;
	}

	DEBUG(5,("allocated fd_ptr structure %d (%d used)\n",
		 i, fd_ptr_used));

	return fd_ptr;
}


/****************************************************************************
close all open files for a connection
****************************************************************************/
void file_close_conn(connection_struct *conn)
{
	files_struct *fsp, *next;
	
	for (fsp=Files;fsp;fsp=next) {
		next = fsp->next;
		if (fsp->conn == conn && fsp->open) {
			if (fsp->is_directory)
				close_directory(fsp); 
			else                  
				close_file(fsp,False); 
		}
	}
}

/****************************************************************************
initialise file structures
****************************************************************************/
void file_init(void)
{
	file_bmap = bitmap_allocate(MAX_FNUMS);
	fd_bmap = bitmap_allocate(MAX_FNUMS);

	if (!file_bmap || !fd_bmap) {
		exit_server("out of memory in file_init");
	}

#if (defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE))
	{
		struct rlimit rlp;
		getrlimit(RLIMIT_NOFILE, &rlp);
		/* Set the fd limit to be MAX_FNUMS + 10 to
		 * account for the extra fd we need 
		 * as well as the log files and standard
		 * handles etc.  */
		rlp.rlim_cur = (MAX_FNUMS+10>rlp.rlim_max)? 
			rlp.rlim_max:MAX_FNUMS+10;
		setrlimit(RLIMIT_NOFILE, &rlp);
		getrlimit(RLIMIT_NOFILE, &rlp);
		DEBUG(3,("Maximum number of open files per session is %d\n",
			 (int)rlp.rlim_cur));
	}
#endif
}


/****************************************************************************
close files open by a specified vuid
****************************************************************************/
void file_close_user(int vuid)
{
	files_struct *fsp, *next;

	for (fsp=Files;fsp;fsp=next) {
		next=fsp->next;
		if ((fsp->vuid == vuid) && fsp->open) {
			if(!fsp->is_directory)
				close_file(fsp,False);
			else
				close_directory(fsp);
		}
	}
}


/****************************************************************************
find a fsp given a device, inode and timevalue
****************************************************************************/
files_struct *file_find_dit(int dev, int inode, struct timeval *tval)
{
	files_struct *fsp;

	for (fsp=Files;fsp;fsp=fsp->next) {
		if (fsp->open && 
		    fsp->fd_ptr->dev == dev && 
		    fsp->fd_ptr->inode == inode &&
		    fsp->open_time.tv_sec == tval->tv_sec &&
		    fsp->open_time.tv_usec == tval->tv_usec) {
			return fsp;
		}
	}

	return NULL;
}


/****************************************************************************
find a fsp that is open for printing
****************************************************************************/
files_struct *file_find_print(void)
{
	files_struct *fsp;

	for (fsp=Files;fsp;fsp=fsp->next) {
		if (fsp->open && fsp->print_file) return fsp;
	} 
	return NULL;
}


/****************************************************************************
sync open files on a connection
****************************************************************************/
void file_sync_all(connection_struct *conn)
{
	files_struct *fsp, *next;

	for (fsp=Files;fsp;fsp=next) {
		next=fsp->next;
		if (fsp->open && conn == fsp->conn) {
			sync_file(conn,fsp);
		}
	}
}


/****************************************************************************
free up a fd_ptr
****************************************************************************/
static void fd_ptr_free(file_fd_struct *fd_ptr)
{
	if (fd_ptr == FileFd) {
		FileFd = fd_ptr->next;
		if (FileFd) FileFd->prev = NULL;
	} else {
		fd_ptr->prev->next = fd_ptr->next;
		if (fd_ptr->next) fd_ptr->next->prev = fd_ptr->prev;
	}

	bitmap_clear(fd_bmap, fd_ptr->fdnum);
	fd_ptr_used--;

	DEBUG(5,("freed fd_ptr structure %d (%d used)\n",
		 fd_ptr->fdnum, fd_ptr_used));

	/* paranoia */
	memset(fd_ptr, 0, sizeof(*fd_ptr));

	free(fd_ptr);
}


/****************************************************************************
free up a fsp
****************************************************************************/
void file_free(files_struct *fsp)
{
	if (fsp == Files) {
		Files = fsp->next;
		if (Files) Files->prev = NULL;
	} else {
		fsp->prev->next = fsp->next;
		if (fsp->next) fsp->next->prev = fsp->prev;
	}

	string_free(&fsp->fsp_name);

	if (fsp->fd_ptr && fsp->fd_ptr->ref_count == 0) {
		fd_ptr_free(fsp->fd_ptr);
	}

	bitmap_clear(file_bmap, fsp->fnum - FILE_HANDLE_OFFSET);
	files_used--;

	DEBUG(5,("freed files structure %d (%d used)\n",
		 fsp->fnum, files_used));

	/* this is paranoia, just in case someone tries to reuse the 
	   information */
	memset(fsp, 0, sizeof(*fsp));

	if (fsp == chain_fsp) chain_fsp = NULL;

	free(fsp);
}


/****************************************************************************
get a fsp from a packet given the offset of a 16 bit fnum
****************************************************************************/
files_struct *file_fsp(char *buf, int where)
{
	int fnum;
	files_struct *fsp;

	if (chain_fsp) return chain_fsp;

	fnum = SVAL(buf, where);

	for (fsp=Files;fsp;fsp=fsp->next) {
		if (fsp->fnum == fnum) {
			chain_fsp = fsp;
			return fsp;
		}
	}

	return NULL;
}


/****************************************************************************
reset the chained fsp - done at the start of a packet reply
****************************************************************************/
void file_chain_reset(void)
{
	chain_fsp = NULL;
}