summaryrefslogtreecommitdiff
path: root/source3/locking/locking_slow.c
blob: 935ed09f60d3b01ffaac2a5eae7cf6cca268a2e6 (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
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
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
/* 
   Unix SMB/Netbios implementation.
   Version 1.9.
   slow (lockfile) locking implementation
   Copyright (C) Andrew Tridgell 1992-1997
   
   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

   May 1997. Jeremy Allison (jallison@whistle.com). Modified share mode
   locking to deal with multiple share modes per open file.

   September 1997. Jeremy Allison (jallison@whistle.com). Added oplock
   support.

   October 1997 - split into separate file (tridge)
*/

#include "includes.h"
extern int DEBUGLEVEL;
extern connection_struct Connections[];
extern files_struct Files[];

/* 
 * Locking file header lengths & offsets. 
 */
#define SMF_VERSION_OFFSET 0
#define SMF_NUM_ENTRIES_OFFSET 4
#define SMF_FILENAME_LEN_OFFSET 8
#define SMF_HEADER_LENGTH 10

#define SMF_ENTRY_LENGTH 20

/*
 * Share mode record offsets.
 */

#define SME_SEC_OFFSET 0
#define SME_USEC_OFFSET 4
#define SME_SHAREMODE_OFFSET 8
#define SME_PID_OFFSET 12
#define SME_PORT_OFFSET 16
#define SME_OPLOCK_TYPE_OFFSET 18

/* we need world read for smbstatus to function correctly */
#ifdef SECURE_SHARE_MODES
#define SHARE_FILE_MODE 0600
#else
#define SHARE_FILE_MODE 0644
#endif

static int read_only;

/*******************************************************************
  deinitialize share_mode management 
  ******************************************************************/
static BOOL slow_stop_share_mode_mgmt(void)
{
   return True;
}


/*******************************************************************
  name a share file
  ******************************************************************/
static BOOL share_name(int cnum, uint32 dev, uint32 inode, char *name)
{
  strcpy(name,lp_lockdir());
  trim_string(name,"","/");
  if (!*name) return(False);
  name += strlen(name);
  
  sprintf(name,"/share.%u.%u",dev,inode);
  return(True);
}

/*******************************************************************
Force a share file to be deleted.
********************************************************************/
static int delete_share_file( int cnum, char *fname )
{
  if (read_only) return -1;

  /* the share file could be owned by anyone, so do this as root */
  become_root(False);

  if(unlink(fname) != 0)
  {
    DEBUG(0,("delete_share_file: Can't delete share file %s (%s)\n",
            fname, strerror(errno)));
  } 
  else 
  {
    DEBUG(5,("delete_share_file: Deleted share file %s\n", fname));
  }

  /* return to our previous privilage level */
  unbecome_root(False);

  return 0;
}

/*******************************************************************
  lock a share mode file.
  ******************************************************************/
static BOOL slow_lock_share_entry(int cnum, uint32 dev, uint32 inode, int *ptok)
{
  pstring fname;
  int fd;
  int ret = True;

  *ptok = (int)-1;

  if(!share_name(cnum, dev, inode, fname))
    return False;

  if (read_only) return True;

  /* we need to do this as root */
  become_root(False);

  {
    BOOL gotlock = False;
    /*
     * There was a race condition in the original slow share mode code.
     * A smbd could open a share mode file, and before getting
     * the lock, another smbd could delete the last entry for
     * the share mode file and delete the file entry from the
     * directory. Thus this smbd would be left with a locked
     * share mode fd attached to a file that no longer had a
     * directory entry. Thus another smbd would think that
     * there were no outstanding opens on the file. To fix
     * this we now check we can do a stat() call on the filename
     * before allowing the lock to proceed, and back out completely
     * and try the open again if we cannot.
     * Jeremy Allison (jallison@whistle.com).
     */

    do
    {
      struct stat dummy_stat;

      fd = (int)open(fname,read_only?O_RDONLY:(O_RDWR|O_CREAT),
		     SHARE_FILE_MODE);

      if(fd < 0)
      {
        DEBUG(0,("ERROR lock_share_entry: failed to open share file %s. Error was %s\n",
                  fname, strerror(errno)));
        ret = False;
        break;
      }

       /* At this point we have an open fd to the share mode file. 
         Lock the first byte exclusively to signify a lock. */
      if(fcntl_lock(fd, F_SETLKW, 0, 1, F_WRLCK) == False)
      {
        DEBUG(0,("ERROR lock_share_entry: fcntl_lock on file %s failed with %s\n",
                  fname, strerror(errno)));   
        close(fd);
        ret = False;
        break;
      }

      /* 
       * If we cannot stat the filename, the file was deleted between
       * the open and the lock call. Back out and try again.
       */

      if(stat(fname, &dummy_stat)!=0)
      {
        DEBUG(2,("lock_share_entry: Re-issuing open on %s to fix race. Error was %s\n",
                fname, strerror(errno)));
        close(fd);
      }
      else
        gotlock = True;
    } while(!gotlock);

    /*
     * We have to come here if any of the above calls fail
     * as we don't want to return and leave ourselves running
     * as root !
     */
  }

  *ptok = (int)fd;

  /* return to our previous privilage level */
  unbecome_root(False);

  return ret;
}

/*******************************************************************
  unlock a share mode file.
  ******************************************************************/
static BOOL slow_unlock_share_entry(int cnum, uint32 dev, uint32 inode, int token)
{
  int fd = (int)token;
  int ret = True;
  struct stat sb;
  pstring fname;

  if (read_only) return True;

  /* Fix for zero length share files from
     Gerald Werner <wernerg@mfldclin.edu> */
    
  share_name(cnum, dev, inode, fname);

  /* get the share mode file size */
  if(fstat((int)token, &sb) != 0)
  {
    DEBUG(0,("ERROR: unlock_share_entry: Failed to do stat on share file %s (%s)\n",
              fname, strerror(errno)));
    sb.st_size = 1;
    ret = False;
  }

  /* If the file was zero length, we must delete before
     doing the unlock to avoid a race condition (see
     the code in lock_share_mode_entry for details.
   */

  /* remove the share file if zero length */    
  if(sb.st_size == 0)  
    delete_share_file(cnum, fname);

  /* token is the fd of the open share mode file. */
  /* Unlock the first byte. */
  if(fcntl_lock(fd, F_SETLKW, 0, 1, F_UNLCK) == False)
   { 
      DEBUG(0,("ERROR unlock_share_entry: fcntl_lock failed with %s\n",
                      strerror(errno)));   
      ret = False;
   }
 
  close(fd);
  return ret;
}

/*******************************************************************
Read a share file into a buffer.
********************************************************************/
static int read_share_file(int cnum, int fd, char *fname, char **out, BOOL *p_new_file)
{
  struct stat sb;
  char *buf;
  int size;

  *out = 0;
  *p_new_file = False;

  if(fstat(fd, &sb) != 0)
  {
    DEBUG(0,("ERROR: read_share_file: Failed to do stat on share file %s (%s)\n",
                  fname, strerror(errno)));
    return -1;
  }

  if(sb.st_size == 0)
  {
     *p_new_file = True;
     return 0;
  }

  /* Allocate space for the file */
  if((buf = (char *)malloc(sb.st_size)) == NULL)
  {
    DEBUG(0,("read_share_file: malloc for file size %d fail !\n", sb.st_size));
    return -1;
  }
  
  if(lseek(fd, 0, SEEK_SET) != 0)
  {
    DEBUG(0,("ERROR: read_share_file: Failed to reset position to 0 \
for share file %s (%s)\n", fname, strerror(errno)));
    if(buf)
      free(buf);
    return -1;
  }
  
  if (read(fd,buf,sb.st_size) != sb.st_size)
  {
    DEBUG(0,("ERROR: read_share_file: Failed to read share file %s (%s)\n",
               fname, strerror(errno)));
    if(buf)
      free(buf);
    return -1;
  }
  
  if (IVAL(buf,SMF_VERSION_OFFSET) != LOCKING_VERSION) {
    DEBUG(0,("ERROR: read_share_file: share file %s has incorrect \
locking version (was %d, should be %d).\n",fname, 
                    IVAL(buf,SMF_VERSION_OFFSET), LOCKING_VERSION));
   if(buf)
      free(buf);
    delete_share_file(cnum, fname);
    return -1;
  }

  /* Sanity check for file contents */
  size = sb.st_size;
  size -= SMF_HEADER_LENGTH; /* Remove the header */

  /* Remove the filename component. */
  size -= SVAL(buf, SMF_FILENAME_LEN_OFFSET);

  /* The remaining size must be a multiple of SMF_ENTRY_LENGTH - error if not. */
  if((size % SMF_ENTRY_LENGTH) != 0)
  {
    DEBUG(0,("ERROR: read_share_file: share file %s is an incorrect length - \
deleting it.\n", fname));
    if(buf)
      free(buf);
    delete_share_file(cnum, fname);
    return -1;
  }

  *out = buf;
  return 0;
}

/*******************************************************************
get all share mode entries in a share file for a dev/inode pair.
********************************************************************/
static int slow_get_share_modes(int cnum, int token, uint32 dev, uint32 inode, 
				share_mode_entry **old_shares)
{
  int fd = (int)token;
  pstring fname;
  int i;
  int num_entries;
  int num_entries_copied;
  int newsize;
  share_mode_entry *share_array;
  char *buf = 0;
  char *base = 0;
  BOOL new_file;

  *old_shares = 0;

  /* Read the share file header - this is of the form:
     0   -  locking version.
     4   -  number of share mode entries.
     8   -  2 byte name length
     [n bytes] file name (zero terminated).

   Followed by <n> share mode entries of the form :

     0   -  tv_sec
     4   -  tv_usec
     8   -  share_mode
    12   -  pid
    16   -  oplock port (if oplocks in use) - 2 bytes.
  */

  share_name(cnum, dev, inode, fname);

  if(read_share_file( cnum, fd, fname, &buf, &new_file) != 0)
  {
    DEBUG(0,("ERROR: get_share_modes: Failed to read share file %s\n",
                  fname));
    return 0;
  }

  if(new_file == True)
    return 0;

  num_entries = IVAL(buf,SMF_NUM_ENTRIES_OFFSET);

  DEBUG(5,("get_share_modes: share file %s has %d share mode entries.\n",
            fname, num_entries));

  /* PARANOIA TEST */
  if(num_entries < 0)
  {
    DEBUG(0,("PANIC ERROR:get_share_mode: num_share_mode_entries < 0 (%d) \
for share file %d\n", num_entries, fname));
    return 0;
  }

  if(num_entries)
  {
    *old_shares = share_array = (share_mode_entry *)
                 malloc(num_entries * sizeof(share_mode_entry));
    if(*old_shares == 0)
    {
      DEBUG(0,("get_share_modes: malloc fail !\n"));
      return 0;
    }
  } 
  else
  {
    /* No entries - just delete the file. */
    DEBUG(0,("get_share_modes: share file %s has no share mode entries - deleting.\n",
              fname));
    if(buf)
      free(buf);
    delete_share_file(cnum, fname);
    return 0;
  }

  num_entries_copied = 0;
  base = buf + SMF_HEADER_LENGTH + SVAL(buf,SMF_FILENAME_LEN_OFFSET);

  for( i = 0; i < num_entries; i++)
  {
    int pid;
    char *p = base + (i*SMF_ENTRY_LENGTH);

    pid = IVAL(p,SME_PID_OFFSET);

    if(!process_exists(pid))
    {
      DEBUG(0,("get_share_modes: process %d no longer exists and \
it left a share mode entry with mode 0x%X in share file %s\n",
            pid, IVAL(p,SME_SHAREMODE_OFFSET), fname));
      continue;
    }
    share_array[num_entries_copied].time.tv_sec = IVAL(p,SME_SEC_OFFSET);
    share_array[num_entries_copied].time.tv_usec = IVAL(p,SME_USEC_OFFSET);
    share_array[num_entries_copied].share_mode = IVAL(p,SME_SHAREMODE_OFFSET);
    share_array[num_entries_copied].pid = pid;
    share_array[num_entries_copied].op_port = SVAL(p,SME_PORT_OFFSET);
    share_array[num_entries_copied].op_type = SVAL(p,SME_OPLOCK_TYPE_OFFSET);

    num_entries_copied++;
  }

  if(num_entries_copied == 0)
  {
    /* Delete the whole file. */
    DEBUG(0,("get_share_modes: share file %s had no valid entries - deleting it !\n",
             fname));
    if(*old_shares)
      free((char *)*old_shares);
    *old_shares = 0;
    if(buf)
      free(buf);
    delete_share_file(cnum, fname);
    return 0;
  }

  /* If we deleted some entries we need to re-write the whole number of
     share mode entries back into the file. */

  if(num_entries_copied != num_entries)
  {
    if(lseek(fd, 0, SEEK_SET) != 0)
    {
      DEBUG(0,("ERROR: get_share_modes: lseek failed to reset to \
position 0 for share mode file %s (%s)\n", fname, strerror(errno)));
      if(*old_shares)
        free((char *)*old_shares);
      *old_shares = 0;
      if(buf)
        free(buf);
      return 0;
    }

    SIVAL(buf, SMF_NUM_ENTRIES_OFFSET, num_entries_copied);
    for( i = 0; i < num_entries_copied; i++)
    {
      char *p = base + (i*SMF_ENTRY_LENGTH);

      SIVAL(p,SME_PID_OFFSET,share_array[i].pid);
      SIVAL(p,SME_SHAREMODE_OFFSET,share_array[i].share_mode);
      SIVAL(p,SME_SEC_OFFSET,share_array[i].time.tv_sec);
      SIVAL(p,SME_USEC_OFFSET,share_array[i].time.tv_usec);
      SSVAL(p,SME_PORT_OFFSET,share_array[i].op_port);
      SSVAL(p,SME_OPLOCK_TYPE_OFFSET,share_array[i].op_type);
    }

    newsize = (base - buf) + (SMF_ENTRY_LENGTH*num_entries_copied);
    if(write(fd, buf, newsize) != newsize)
    {
      DEBUG(0,("ERROR: get_share_modes: failed to re-write share \
mode file %s (%s)\n", fname, strerror(errno)));
      if(*old_shares)
        free((char *)*old_shares);
      *old_shares = 0;
      if(buf)
        free(buf);
      return 0;
    }
    /* Now truncate the file at this point. */
    if(ftruncate(fd, newsize)!= 0)
    {
      DEBUG(0,("ERROR: get_share_modes: failed to ftruncate share \
mode file %s to size %d (%s)\n", fname, newsize, strerror(errno)));
      if(*old_shares)
        free((char *)*old_shares);
      *old_shares = 0;
      if(buf)
        free(buf);
      return 0;
    }
  }

  if(buf)
    free(buf);

  DEBUG(5,("get_share_modes: Read share file %s returning %d entries\n",fname,
            num_entries_copied));

  return num_entries_copied;
}

/*******************************************************************
del a share mode from a share mode file.
********************************************************************/
static void slow_del_share_mode(int token, int fnum)
{
  pstring fname;
  int fd = (int)token;
  char *buf = 0;
  char *base = 0;
  int num_entries;
  int newsize;
  int i;
  files_struct *fs_p = &Files[fnum];
  int pid;
  BOOL deleted = False;
  BOOL new_file;

  share_name(fs_p->cnum, fs_p->fd_ptr->dev, 
                       fs_p->fd_ptr->inode, fname);

  if(read_share_file( fs_p->cnum, fd, fname, &buf, &new_file) != 0)
  {
    DEBUG(0,("ERROR: del_share_mode: Failed to read share file %s\n",
                  fname));
    return;
  }

  if(new_file == True)
  {
    DEBUG(0,("ERROR:del_share_mode: share file %s is new (size zero), deleting it.\n",
              fname));
    delete_share_file(fs_p->cnum, fname);
    return;
  }

  num_entries = IVAL(buf,SMF_NUM_ENTRIES_OFFSET);

  DEBUG(5,("del_share_mode: share file %s has %d share mode entries.\n",
            fname, num_entries));

  /* PARANOIA TEST */
  if(num_entries < 0)
  {
    DEBUG(0,("PANIC ERROR:del_share_mode: num_share_mode_entries < 0 (%d) \
for share file %d\n", num_entries, fname));
    return;
  }

  if(num_entries == 0)
  {
    /* No entries - just delete the file. */
    DEBUG(0,("del_share_mode: share file %s has no share mode entries - deleting.\n",
              fname));
    if(buf)
      free(buf);
    delete_share_file(fs_p->cnum, fname);
    return;
  }

  pid = getpid();

  /* Go through the entries looking for the particular one
     we have set - delete it.
  */

  base = buf + SMF_HEADER_LENGTH + SVAL(buf,SMF_FILENAME_LEN_OFFSET);

  for(i = 0; i < num_entries; i++)
  {
    char *p = base + (i*SMF_ENTRY_LENGTH);

    if((IVAL(p,SME_SEC_OFFSET) != fs_p->open_time.tv_sec) || 
       (IVAL(p,SME_USEC_OFFSET) != fs_p->open_time.tv_usec) ||
       (IVAL(p,SME_SHAREMODE_OFFSET) != fs_p->share_mode) || 
       (IVAL(p,SME_PID_OFFSET) != pid))
      continue;

    DEBUG(5,("del_share_mode: deleting entry number %d (of %d) from the share file %s\n",
             i, num_entries, fname));

    /* Remove this entry. */
    if(i != num_entries - 1)
      memcpy(p, p + SMF_ENTRY_LENGTH, (num_entries - i - 1)*SMF_ENTRY_LENGTH);

    deleted = True;
    break;
  }

  if(!deleted)
  {
    DEBUG(0,("del_share_mode: entry not found in share file %s\n", fname));
    if(buf)
      free(buf);
    return;
  }

  num_entries--;
  SIVAL(buf,SMF_NUM_ENTRIES_OFFSET, num_entries);

  if(num_entries == 0)
  {
    /* Deleted the last entry - remove the file. */
    DEBUG(5,("del_share_mode: removed last entry in share file - deleting share file %s\n",
             fname));
    if(buf)
      free(buf);
    delete_share_file(fs_p->cnum,fname);
    return;
  }

  /* Re-write the file - and truncate it at the correct point. */
  if(lseek(fd, 0, SEEK_SET) != 0)
  {
    DEBUG(0,("ERROR: del_share_mode: lseek failed to reset to \
position 0 for share mode file %s (%s)\n", fname, strerror(errno)));
    if(buf)
      free(buf);
    return;
  }

  newsize = (base - buf) + (SMF_ENTRY_LENGTH*num_entries);
  if(write(fd, buf, newsize) != newsize)
  {
    DEBUG(0,("ERROR: del_share_mode: failed to re-write share \
mode file %s (%s)\n", fname, strerror(errno)));
    if(buf)
      free(buf);
    return;
  }
  /* Now truncate the file at this point. */
  if(ftruncate(fd, newsize) != 0)
  {
    DEBUG(0,("ERROR: del_share_mode: failed to ftruncate share \
mode file %s to size %d (%s)\n", fname, newsize, strerror(errno)));
    if(buf)
      free(buf);
    return;
  }
}
  
/*******************************************************************
set the share mode of a file
********************************************************************/
static BOOL slow_set_share_mode(int token,int fnum, uint16 port, uint16 op_type)
{
  files_struct *fs_p = &Files[fnum];
  pstring fname;
  int fd = (int)token;
  int pid = (int)getpid();
  struct stat sb;
  char *buf;
  int num_entries;
  int header_size;
  char *p;

  share_name(fs_p->cnum, fs_p->fd_ptr->dev,
                       fs_p->fd_ptr->inode, fname);

  if(fstat(fd, &sb) != 0)
  {
    DEBUG(0,("ERROR: set_share_mode: Failed to do stat on share file %s\n",
                  fname));
    return False;
  }

  /* Sanity check for file contents (if it's not a new share file). */
  if(sb.st_size != 0)
  {
    int size = sb.st_size;

    /* Allocate space for the file plus one extra entry */
    if((buf = (char *)malloc(sb.st_size + SMF_ENTRY_LENGTH)) == NULL)
    {
      DEBUG(0,("set_share_mode: malloc for file size %d fail !\n", 
                  sb.st_size + SMF_ENTRY_LENGTH));
      return False;
    }
 
    if(lseek(fd, 0, SEEK_SET) != 0)
    {
      DEBUG(0,("ERROR: set_share_mode: Failed to reset position \
to 0 for share file %s (%s)\n", fname, strerror(errno)));
      if(buf)
        free(buf);
      return False;
    }

    if (read(fd,buf,sb.st_size) != sb.st_size)
    {
      DEBUG(0,("ERROR: set_share_mode: Failed to read share file %s (%s)\n",
                  fname, strerror(errno)));
      if(buf)
        free(buf);
      return False;
    }   
  
    if (IVAL(buf,SMF_VERSION_OFFSET) != LOCKING_VERSION) 
    {
      DEBUG(0,("ERROR: set_share_mode: share file %s has incorrect \
locking version (was %d, should be %d).\n",fname, IVAL(buf,SMF_VERSION_OFFSET), 
                    LOCKING_VERSION));
      if(buf)
        free(buf);
      delete_share_file(fs_p->cnum, fname);
      return False;
    }   

    size -= (SMF_HEADER_LENGTH + SVAL(buf, SMF_FILENAME_LEN_OFFSET)); /* Remove the header */

    /* The remaining size must be a multiple of SMF_ENTRY_LENGTH - error if not. */
    if((size % SMF_ENTRY_LENGTH) != 0)
    {
      DEBUG(0,("ERROR: set_share_mode: share file %s is an incorrect length - \
deleting it.\n", fname));
      if(buf)
        free(buf);
      delete_share_file(fs_p->cnum, fname);
      return False;
    }

  }
  else
  {
    /* New file - just use a single_entry. */
    if((buf = (char *)malloc(SMF_HEADER_LENGTH + 
                  strlen(fs_p->name) + 1 + SMF_ENTRY_LENGTH)) == NULL)
    {
      DEBUG(0,("ERROR: set_share_mode: malloc failed for single entry.\n"));
      return False;
    }
    SIVAL(buf,SMF_VERSION_OFFSET,LOCKING_VERSION);
    SIVAL(buf,SMF_NUM_ENTRIES_OFFSET,0);
    SSVAL(buf,SMF_FILENAME_LEN_OFFSET,strlen(fs_p->name) + 1);
    strcpy(buf + SMF_HEADER_LENGTH, fs_p->name);
  }

  num_entries = IVAL(buf,SMF_NUM_ENTRIES_OFFSET);
  header_size = SMF_HEADER_LENGTH + SVAL(buf,SMF_FILENAME_LEN_OFFSET);
  p = buf + header_size + (num_entries * SMF_ENTRY_LENGTH);
  SIVAL(p,SME_SEC_OFFSET,fs_p->open_time.tv_sec);
  SIVAL(p,SME_USEC_OFFSET,fs_p->open_time.tv_usec);
  SIVAL(p,SME_SHAREMODE_OFFSET,fs_p->share_mode);
  SIVAL(p,SME_PID_OFFSET,pid);
  SSVAL(p,SME_PORT_OFFSET,port);
  SSVAL(p,SME_OPLOCK_TYPE_OFFSET,op_type);

  num_entries++;

  SIVAL(buf,SMF_NUM_ENTRIES_OFFSET,num_entries);

  if(lseek(fd, 0, SEEK_SET) != 0)
  {
    DEBUG(0,("ERROR: set_share_mode: (1) Failed to reset position to \
0 for share file %s (%s)\n", fname, strerror(errno)));
    if(buf)
      free(buf);
    return False;
  }

  if (write(fd,buf,header_size + (num_entries*SMF_ENTRY_LENGTH)) != 
                       (header_size + (num_entries*SMF_ENTRY_LENGTH))) 
  {
    DEBUG(2,("ERROR: set_share_mode: Failed to write share file %s - \
deleting it (%s).\n",fname, strerror(errno)));
    delete_share_file(fs_p->cnum, fname);
    if(buf)
      free(buf);
    return False;
  }

  /* Now truncate the file at this point - just for safety. */
  if(ftruncate(fd, header_size + (SMF_ENTRY_LENGTH*num_entries))!= 0)
  {
    DEBUG(0,("ERROR: set_share_mode: failed to ftruncate share \
mode file %s to size %d (%s)\n", fname, header_size + (SMF_ENTRY_LENGTH*num_entries), 
                strerror(errno)));
    if(buf)
      free(buf);
    return False;
  }

  if(buf)
    free(buf);

  DEBUG(3,("set_share_mode: Created share file %s with \
mode 0x%X pid=%d\n",fname,fs_p->share_mode,pid));

  return True;
}

/*******************************************************************
Remove an oplock port and mode entry from a share mode.
********************************************************************/
static BOOL slow_remove_share_oplock(int fnum, int token)
{
  pstring fname;
  int fd = (int)token;
  char *buf = 0;
  char *base = 0;
  int num_entries;
  int fsize;
  int i;
  files_struct *fs_p = &Files[fnum];
  int pid;
  BOOL found = False;
  BOOL new_file;

  share_name(fs_p->cnum, fs_p->fd_ptr->dev, 
                       fs_p->fd_ptr->inode, fname);

  if(read_share_file( fs_p->cnum, fd, fname, &buf, &new_file) != 0)
  {
    DEBUG(0,("ERROR: remove_share_oplock: Failed to read share file %s\n",
                  fname));
    return False;
  }

  if(new_file == True)
  {
    DEBUG(0,("ERROR: remove_share_oplock: share file %s is new (size zero), \
deleting it.\n", fname));
    delete_share_file(fs_p->cnum, fname);
    return False;
  }

  num_entries = IVAL(buf,SMF_NUM_ENTRIES_OFFSET);

  DEBUG(5,("remove_share_oplock: share file %s has %d share mode entries.\n",
            fname, num_entries));

  /* PARANOIA TEST */
  if(num_entries < 0)
  {
    DEBUG(0,("PANIC ERROR:remove_share_oplock: num_share_mode_entries < 0 (%d) \
for share file %d\n", num_entries, fname));
    return False;
  }

  if(num_entries == 0)
  {
    /* No entries - just delete the file. */
    DEBUG(0,("remove_share_oplock: share file %s has no share mode entries - deleting.\n",
              fname));
    if(buf)
      free(buf);
    delete_share_file(fs_p->cnum, fname);
    return False;
  }

  pid = getpid();

  /* Go through the entries looking for the particular one
     we have set - remove the oplock settings on it.
  */

  base = buf + SMF_HEADER_LENGTH + SVAL(buf,SMF_FILENAME_LEN_OFFSET);

  for(i = 0; i < num_entries; i++)
  {
    char *p = base + (i*SMF_ENTRY_LENGTH);

    if((IVAL(p,SME_SEC_OFFSET) != fs_p->open_time.tv_sec) || 
       (IVAL(p,SME_USEC_OFFSET) != fs_p->open_time.tv_usec) ||
       (IVAL(p,SME_SHAREMODE_OFFSET) != fs_p->share_mode) || 
       (IVAL(p,SME_PID_OFFSET) != pid))
      continue;

    DEBUG(5,("remove_share_oplock: clearing oplock on entry number %d (of %d) \
from the share file %s\n", i, num_entries, fname));

    SSVAL(p,SME_PORT_OFFSET,0);
    SSVAL(p,SME_OPLOCK_TYPE_OFFSET,0);
    found = True;
    break;
  }

  if(!found)
  {
    DEBUG(0,("remove_share_oplock: entry not found in share file %s\n", fname));
    if(buf)
      free(buf);
    return False;
  }

  /* Re-write the file - and truncate it at the correct point. */
  if(lseek(fd, 0, SEEK_SET) != 0)
  {
    DEBUG(0,("ERROR: remove_share_oplock: lseek failed to reset to \
position 0 for share mode file %s (%s)\n", fname, strerror(errno)));
    if(buf)
      free(buf);
    return False;
  }

  fsize = (base - buf) + (SMF_ENTRY_LENGTH*num_entries);
  if(write(fd, buf, fsize) != fsize)
  {
    DEBUG(0,("ERROR: remove_share_oplock: failed to re-write share \
mode file %s (%s)\n", fname, strerror(errno)));
    if(buf)
      free(buf);
    return False;
  }

  return True;
}



/*******************************************************************
call the specified function on each entry under management by the
share ode system
********************************************************************/
static int slow_share_forall(void (*fn)(share_mode_entry *, char *))
{
	int i, count=0;
	void *dir;
	char *s;
	share_mode_entry e;

	dir = opendir(lp_lockdir());
	if (!dir) {
		return(0);
	}

	while ((s=readdirname(dir))) {
		char *buf;
		char *base;
		int fd;
		pstring lname;
		uint32 dev,inode;
		BOOL new_file;
		pstring fname;

		if (sscanf(s,"share.%u.%u",&dev,&inode)!=2) continue;
       
		strcpy(lname,lp_lockdir());
		trim_string(lname,NULL,"/");
		strcat(lname,"/");
		strcat(lname,s);
       
		fd = open(lname,read_only?O_RDONLY:O_RDWR,0);
		if (fd < 0) {
			continue;
		}

		/* Lock the share mode file while we read it. */
		if(!read_only &&
		   fcntl_lock(fd, F_SETLKW, 0, 1, F_WRLCK) == False) {
			close(fd);
			continue;
		}

		if(read_share_file( 0, fd, lname, &buf, &new_file)) {
			close(fd);
			continue;
		} 
		strcpy( fname, &buf[10]);
		close(fd);
      
		base = buf + SMF_HEADER_LENGTH + 
			SVAL(buf,SMF_FILENAME_LEN_OFFSET); 
		for( i = 0; i < IVAL(buf, SMF_NUM_ENTRIES_OFFSET); i++) {
			char *p = base + (i*SMF_ENTRY_LENGTH);
			e.pid = IVAL(p,SME_PID_OFFSET);
			e.share_mode = IVAL(p,SME_SHAREMODE_OFFSET);
			e.time.tv_sec = IVAL(p,SME_SEC_OFFSET);
			e.time.tv_usec = IVAL(p,SME_USEC_OFFSET);
			e.op_port = SVAL(p,SME_PORT_OFFSET);
			e.pid = SVAL(p,SME_PID_OFFSET);
			e.op_type = SVAL(p,SME_OPLOCK_TYPE_OFFSET);

			if (process_exists(e.pid)) {
				fn(&e, fname);
				count++;
			}
		} /* end for i */

		if(buf)
			free(buf);
		base = 0;
	} /* end while */
	closedir(dir);

	return count;
}


/*******************************************************************
dump the state of the system
********************************************************************/
static void slow_share_status(FILE *f)
{
	
}


static struct share_ops share_ops = {
	slow_stop_share_mode_mgmt,
	slow_lock_share_entry,
	slow_unlock_share_entry,
	slow_get_share_modes,
	slow_del_share_mode,
	slow_set_share_mode,
	slow_remove_share_oplock,
	slow_share_forall,
	slow_share_status,
};

/*******************************************************************
  initialize the slow share_mode management 
  ******************************************************************/
struct share_ops *locking_slow_init(int ronly)
{

	read_only = ronly;

	if (!directory_exist(lp_lockdir(),NULL)) {
		if (!read_only)
			mkdir(lp_lockdir(),0755);
		if (!directory_exist(lp_lockdir(),NULL))
			return NULL;
	}

	return &share_ops;
}