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
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
|
/*
Unix SMB/Netbios implementation.
Version 1.9.
Locking functions
Copyright (C) Andrew Tridgell 1992-1996
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.
Revision History:
12 aug 96: Erik.Devriendt@te6.siemens.be
added support for shared memory implementation of share mode locking
*/
#include "includes.h"
extern int DEBUGLEVEL;
extern connection_struct Connections[];
extern files_struct Files[];
pstring share_del_pending="";
/****************************************************************************
routine to do file locking
****************************************************************************/
BOOL fcntl_lock(int fd,int op,uint32 offset,uint32 count,int type)
{
#if HAVE_FCNTL_LOCK
struct flock lock;
int ret;
#if 1
uint32 mask = 0xC0000000;
/* make sure the count is reasonable, we might kill the lockd otherwise */
count &= ~mask;
/* the offset is often strange - remove 2 of its bits if either of
the top two bits are set. Shift the top ones by two bits. This
still allows OLE2 apps to operate, but should stop lockd from
dieing */
if ((offset & mask) != 0)
offset = (offset & ~mask) | ((offset & mask) >> 2);
#else
uint32 mask = ((unsigned)1<<31);
/* interpret negative counts as large numbers */
if (count < 0)
count &= ~mask;
/* no negative offsets */
offset &= ~mask;
/* count + offset must be in range */
while ((offset < 0 || (offset + count < 0)) && mask)
{
offset &= ~mask;
mask = mask >> 1;
}
#endif
DEBUG(5,("fcntl_lock %d %d %d %d %d\n",fd,op,(int)offset,(int)count,type));
lock.l_type = type;
lock.l_whence = SEEK_SET;
lock.l_start = (int)offset;
lock.l_len = (int)count;
lock.l_pid = 0;
errno = 0;
ret = fcntl(fd,op,&lock);
if (errno != 0)
DEBUG(3,("fcntl lock gave errno %d (%s)\n",errno,strerror(errno)));
/* a lock query */
if (op == F_GETLK)
{
if ((ret != -1) &&
(lock.l_type != F_UNLCK) &&
(lock.l_pid != 0) &&
(lock.l_pid != getpid()))
{
DEBUG(3,("fd %d is locked by pid %d\n",fd,lock.l_pid));
return(True);
}
/* it must be not locked or locked by me */
return(False);
}
/* a lock set or unset */
if (ret == -1)
{
DEBUG(3,("lock failed at offset %d count %d op %d type %d (%s)\n",
offset,count,op,type,strerror(errno)));
/* perhaps it doesn't support this sort of locking?? */
if (errno == EINVAL)
{
DEBUG(3,("locking not supported? returning True\n"));
return(True);
}
return(False);
}
/* everything went OK */
DEBUG(5,("Lock call successful\n"));
return(True);
#else
return(False);
#endif
}
/*******************************************************************
lock a file - returning a open file descriptor or -1 on failure
The timeout is in seconds. 0 means no timeout
********************************************************************/
int file_lock(char *name,int timeout)
{
int fd = open(name,O_RDWR|O_CREAT,0666);
time_t t=0;
if (fd < 0) return(-1);
#if HAVE_FCNTL_LOCK
if (timeout) t = time(NULL);
while (!timeout || (time(NULL)-t < timeout)) {
if (fcntl_lock(fd,F_SETLK,0,1,F_WRLCK)) return(fd);
msleep(LOCK_RETRY_TIMEOUT);
}
return(-1);
#else
return(fd);
#endif
}
/*******************************************************************
unlock a file locked by file_lock
********************************************************************/
void file_unlock(int fd)
{
if (fd<0) return;
#if HAVE_FCNTL_LOCK
fcntl_lock(fd,F_SETLK,0,1,F_UNLCK);
#endif
close(fd);
}
/****************************************************************************
utility function called to see if a file region is locked
****************************************************************************/
BOOL is_locked(int fnum,int cnum,uint32 count,uint32 offset)
{
int snum = SNUM(cnum);
if (count == 0)
return(False);
if (!lp_locking(snum) || !lp_strict_locking(snum))
return(False);
return(fcntl_lock(Files[fnum].fd,F_GETLK,offset,count,
(Files[fnum].can_write?F_WRLCK:F_RDLCK)));
}
/****************************************************************************
utility function called by locking requests
****************************************************************************/
BOOL do_lock(int fnum,int cnum,uint32 count,uint32 offset,int *eclass,uint32 *ecode)
{
BOOL ok = False;
if (!lp_locking(SNUM(cnum)))
return(True);
if (count == 0) {
*eclass = ERRDOS;
*ecode = ERRnoaccess;
return False;
}
if (Files[fnum].can_lock && OPEN_FNUM(fnum) && (Files[fnum].cnum == cnum))
ok = fcntl_lock(Files[fnum].fd,F_SETLK,offset,count,
(Files[fnum].can_write?F_WRLCK:F_RDLCK));
if (!ok) {
*eclass = ERRDOS;
*ecode = ERRlock;
return False;
}
return True; /* Got lock */
}
/****************************************************************************
utility function called by unlocking requests
****************************************************************************/
BOOL do_unlock(int fnum,int cnum,uint32 count,uint32 offset,int *eclass,uint32 *ecode)
{
BOOL ok = False;
if (!lp_locking(SNUM(cnum)))
return(True);
if (Files[fnum].can_lock && OPEN_FNUM(fnum) && (Files[fnum].cnum == cnum))
ok = fcntl_lock(Files[fnum].fd,F_SETLK,offset,count,F_UNLCK);
if (!ok) {
*eclass = ERRDOS;
*ecode = ERRlock;
return False;
}
return True; /* Did unlock */
}
#ifdef FAST_SHARE_MODES
/*******************************************************************
initialize the shared memory for share_mode management
******************************************************************/
BOOL start_share_mode_mgmt(void)
{
pstring shmem_file_name;
strcpy(shmem_file_name,lp_lockdir());
trim_string(shmem_file_name,"","/");
if (!*shmem_file_name) return(False);
strcat(shmem_file_name, "/SHARE_MEM_FILE");
return shm_open(shmem_file_name, SHMEM_SIZE);
}
/*******************************************************************
deinitialize the shared memory for share_mode management
******************************************************************/
BOOL stop_share_mode_mgmt(void)
{
return shm_close();
}
#else
/* SHARE MODE LOCKS USING SLOW DESCRIPTION FILES */
/*******************************************************************
name a share file
******************************************************************/
static BOOL share_name(int cnum,struct stat *st,char *name)
{
strcpy(name,lp_lockdir());
standard_sub(cnum,name);
trim_string(name,"","/");
if (!*name) return(False);
name += strlen(name);
sprintf(name,"/share.%d.%d",(int)st->st_dev,(int)st->st_ino);
return(True);
}
/*******************************************************************
use the fnum to get the share file name
******************************************************************/
static BOOL share_name_fnum(int fnum,char *name)
{
struct stat st;
if (fstat(Files[fnum].fd,&st) != 0) return(False);
return(share_name(Files[fnum].cnum,&st,name));
}
#endif
/*******************************************************************
get the share mode of a file using the fnum
******************************************************************/
int get_share_mode_by_fnum(int cnum,int fnum,int *pid)
{
struct stat sbuf;
if (fstat(Files[fnum].fd,&sbuf) == -1) return(0);
return(get_share_mode(cnum,&sbuf,pid));
}
/*******************************************************************
get the share mode of a file using the files name
******************************************************************/
int get_share_mode_byname(int cnum,char *fname,int *pid)
{
struct stat sbuf;
if (stat(fname,&sbuf) == -1) return(0);
return(get_share_mode(cnum,&sbuf,pid));
}
/*******************************************************************
get the share mode of a file
********************************************************************/
int get_share_mode(int cnum,struct stat *sbuf,int *pid)
{
#ifdef FAST_SHARE_MODES
share_mode_record *scanner_p;
share_mode_record *prev_p;
int ret;
BOOL found = False;
*pid = 0;
if(!shm_lock()) return (0);
scanner_p = (share_mode_record *)shm_offset2addr(shm_get_userdef_off());
prev_p = scanner_p;
while(scanner_p)
{
if( (scanner_p->st_dev == sbuf->st_dev) && (scanner_p->st_ino == sbuf->st_ino) )
{
found = True;
break;
}
else
{
prev_p = scanner_p ;
scanner_p = (share_mode_record *)shm_offset2addr(scanner_p->next_offset);
}
}
if(!found)
{
shm_unlock();
return (0);
}
if(scanner_p->locking_version != LOCKING_VERSION)
{
DEBUG(2,("Deleting old share mode record due to old locking version %d",scanner_p->locking_version));
if(prev_p == scanner_p)
shm_set_userdef_off(scanner_p->next_offset);
else
prev_p->next_offset = scanner_p->next_offset;
shm_free(shm_addr2offset(scanner_p));
*pid = 0;
shm_unlock();
return (0);
}
*pid = scanner_p->pid;
ret = scanner_p->share_mode;
if (*pid && !process_exists(*pid))
{
ret = 0;
*pid = 0;
}
if (! *pid)
{
if(prev_p == scanner_p)
shm_set_userdef_off(scanner_p->next_offset);
else
prev_p->next_offset = scanner_p->next_offset;
shm_free(shm_addr2offset(scanner_p));
}
if (*pid)
DEBUG(5,("Read share mode record mode 0x%X pid=%d\n",ret,*pid));
if(!shm_unlock()) return (0);
return(ret);
#else
pstring fname;
int fd2;
char buf[16];
int ret;
time_t t;
*pid = 0;
if (!share_name(cnum,sbuf,fname)) return(0);
fd2 = open(fname,O_RDONLY,0);
if (fd2 < 0) return(0);
if (read(fd2,buf,16) != 16) {
close(fd2);
unlink(fname);
return(0);
}
close(fd2);
t = IVAL(buf,0);
ret = IVAL(buf,4);
*pid = IVAL(buf,8);
if (IVAL(buf,12) != LOCKING_VERSION) {
if (!unlink(fname)) DEBUG(2,("Deleted old locking file %s",fname));
*pid = 0;
return(0);
}
if (*pid && !process_exists(*pid)) {
ret=0;
*pid = 0;
}
if (! *pid) unlink(fname); /* XXXXX race, race */
if (*pid)
DEBUG(5,("Read share file %s mode 0x%X pid=%d\n",fname,ret,*pid));
return(ret);
#endif
}
/*******************************************************************
del the share mode of a file, if we set it last
********************************************************************/
void del_share_mode(int fnum)
{
#ifdef FAST_SHARE_MODES
struct stat st;
time_t t=0;
int pid=0;
BOOL del = False;
share_mode_record *scanner_p;
share_mode_record *prev_p;
BOOL found = False;
if (fstat(Files[fnum].fd,&st) != 0) return;
if (!shm_lock()) return;
scanner_p = (share_mode_record *)shm_offset2addr(shm_get_userdef_off());
prev_p = scanner_p;
while(scanner_p)
{
if( (scanner_p->st_dev == st.st_dev) && (scanner_p->st_ino == st.st_ino) )
{
found = True;
break;
}
else
{
prev_p = scanner_p ;
scanner_p = (share_mode_record *)shm_offset2addr(scanner_p->next_offset);
}
}
if(!found)
{
shm_unlock();
return;
}
t = scanner_p->time;
pid = scanner_p->pid;
if( (scanner_p->locking_version != LOCKING_VERSION) || !pid || !process_exists(pid))
del = True;
if (!del && t == Files[fnum].open_time && pid==(int)getpid())
del = True;
if (del)
{
DEBUG(2,("Deleting share mode record\n"));
if(prev_p == scanner_p)
shm_set_userdef_off(scanner_p->next_offset);
else
prev_p->next_offset = scanner_p->next_offset;
shm_free(shm_addr2offset(scanner_p));
}
shm_unlock();
return;
#else
pstring fname;
int fd2;
char buf[16];
time_t t=0;
int pid=0;
BOOL del = False;
if (!share_name_fnum(fnum,fname)) return;
fd2 = open(fname,O_RDONLY,0);
if (fd2 < 0) return;
if (read(fd2,buf,16) != 16)
del = True;
close(fd2);
if (!del) {
t = IVAL(buf,0);
pid = IVAL(buf,8);
}
if (!del)
if (IVAL(buf,12) != LOCKING_VERSION || !pid || !process_exists(pid))
del = True;
if (!del && t == Files[fnum].open_time && pid==(int)getpid())
del = True;
if (del) {
if (!unlink(fname))
DEBUG(2,("Deleted share file %s\n",fname));
else {
DEBUG(3,("Pending delete share file %s\n",fname));
if (*share_del_pending) DEBUG(0,("Share del clash!\n"));
strcpy(share_del_pending,fname);
}
}
#endif
}
/*******************************************************************
set the share mode of a file
********************************************************************/
BOOL set_share_mode(int fnum,int mode)
{
#ifdef FAST_SHARE_MODES
int pid = (int)getpid();
struct stat st;
shm_offset_t new_off;
share_mode_record *new_p;
if (fstat(Files[fnum].fd,&st) != 0) return(False);
if (!shm_lock()) return (False);
new_off = shm_alloc(sizeof(share_mode_record) + strlen(Files[fnum].name) );
if (new_off == NULL_OFFSET) return (False);
new_p = (share_mode_record *)shm_offset2addr(new_off);
new_p->locking_version = LOCKING_VERSION;
new_p->share_mode = mode;
new_p->time = Files[fnum].open_time;
new_p->pid = pid;
new_p->st_dev = st.st_dev;
new_p->st_ino = st.st_ino;
strcpy(new_p->file_name,Files[fnum].name);
new_p->next_offset = shm_get_userdef_off();
shm_set_userdef_off(new_off);
DEBUG(3,("Created share record for %s with mode 0x%X pid=%d\n",Files[fnum].name,mode,pid));
if (!shm_unlock()) return (False);
return(True);
#else
pstring fname;
int fd2;
char buf[16];
int pid = (int)getpid();
if (!share_name_fnum(fnum,fname)) return(False);
{
int old_umask = umask(0);
fd2 = open(fname,O_WRONLY|O_CREAT|O_TRUNC,0644);
umask(old_umask);
}
if (fd2 < 0) {
DEBUG(2,("Failed to create share file %s\n",fname));
return(False);
}
SIVAL(buf,0,Files[fnum].open_time);
SIVAL(buf,4,mode);
SIVAL(buf,8,pid);
SIVAL(buf,12,LOCKING_VERSION);
if (write(fd2,buf,16) != 16) {
close(fd2);
unlink(fname);
return(False);
}
write(fd2,Files[fnum].name,strlen(Files[fnum].name)+1);
close(fd2);
DEBUG(3,("Created share file %s with mode 0x%X pid=%d\n",fname,mode,pid));
return(True);
#endif
}
/*******************************************************************
cleanup any stale share files
********************************************************************/
void clean_share_modes(void)
{
#ifdef USE_SHMEM
share_mode_record *scanner_p;
share_mode_record *prev_p;
int pid;
if (!shm_lock()) return;
scanner_p = (share_mode_record *)shm_offset2addr(shm_get_userdef_off());
prev_p = scanner_p;
while(scanner_p)
{
pid = scanner_p->pid;
if( (scanner_p->locking_version != LOCKING_VERSION) || !process_exists(pid))
{
DEBUG(2,("Deleting stale share mode record"));
if(prev_p == scanner_p)
{
shm_set_userdef_off(scanner_p->next_offset);
shm_free(shm_addr2offset(scanner_p));
scanner_p = (share_mode_record *)shm_offset2addr(shm_get_userdef_off());
prev_p = scanner_p;
}
else
{
prev_p->next_offset = scanner_p->next_offset;
shm_free(shm_addr2offset(scanner_p));
scanner_p = (share_mode_record *)shm_offset2addr(prev_p->next_offset);
}
}
else
{
prev_p = scanner_p ;
scanner_p = (share_mode_record *)shm_offset2addr(scanner_p->next_offset);
}
}
shm_unlock();
return;
#else
char *lockdir = lp_lockdir();
void *dir;
char *s;
if (!*lockdir) return;
dir = opendir(lockdir);
if (!dir) return;
while ((s=readdirname(dir))) {
char buf[16];
int pid;
int fd;
pstring lname;
int dev,inode;
if (sscanf(s,"share.%d.%d",&dev,&inode)!=2) continue;
strcpy(lname,lp_lockdir());
trim_string(lname,NULL,"/");
strcat(lname,"/");
strcat(lname,s);
fd = open(lname,O_RDONLY,0);
if (fd < 0) continue;
if (read(fd,buf,16) != 16) {
close(fd);
if (!unlink(lname))
printf("Deleted corrupt share file %s\n",s);
continue;
}
close(fd);
pid = IVAL(buf,8);
if (IVAL(buf,12) != LOCKING_VERSION || !process_exists(pid)) {
if (!unlink(lname))
printf("Deleted stale share file %s\n",s);
}
}
closedir(dir);
#endif
}
|