summaryrefslogtreecommitdiff
path: root/imap/src/osdep/nt/mbxnt.c
blob: bb3d4cc085a653e349363cc0cc51921f628edc73 (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
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
/* ========================================================================
 * Copyright 1988-2007 University of Washington
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * 
 * ========================================================================
 */

/*
 * Program:	MBX mail routines
 *
 * Author:	Mark Crispin
 *		Networks and Distributed Computing
 *		Computing & Communications
 *		University of Washington
 *		Administration Building, AG-44
 *		Seattle, WA  98195
 *		Internet: MRC@CAC.Washington.EDU
 *
 * Date:	3 October 1995
 * Last Edited:	28 September 2007
 */


/*				FILE TIME SEMANTICS
 *
 * The atime is the last read time of the file.
 * The mtime is the last flags update time of the file.
 * The ctime is the last write time of the file.
 */

#include <stdio.h>
#include <ctype.h>
#include <errno.h>
extern int errno;		/* just in case */
#include "mail.h"
#include "osdep.h"
#include <fcntl.h>
#include <time.h>
#include <sys/stat.h>
#include <sys/utime.h>
#include "misc.h"
#include "dummy.h"
#include "fdstring.h"


/* Build parameters */

#define HDRSIZE 2048

/* MBX I/O stream local data */
	
typedef struct mbx_local {
  unsigned int flagcheck: 1;	/* if ping should sweep for flags */
  unsigned int expok: 1;	/* if expunging OK in ping */
  unsigned int expunged : 1;	/* if one or more expunged messages */
  int fd;			/* file descriptor for I/O */
  int ld;			/* lock file descriptor */
  int ffuserflag;		/* first free user flag */
  off_t filesize;		/* file size parsed */
  time_t filetime;		/* last file time */
  time_t lastsnarf;		/* last snarf time */
  unsigned char *buf;		/* temporary buffer */
  unsigned long buflen;		/* current size of temporary buffer */
  char lock[MAILTMPLEN];	/* buffer to write lock name */
} MBXLOCAL;


/* Convenient access to local data */

#define LOCAL ((MBXLOCAL *) stream->local)

/* Function prototypes */

DRIVER *mbx_valid (char *name);
int mbx_isvalid (MAILSTREAM **stream,char *name,char *file,int *ld,char *lock,
		 long flags);
void *mbx_parameters (long function,void *value);
void mbx_scan (MAILSTREAM *stream,char *ref,char *pat,char *contents);
void mbx_list (MAILSTREAM *stream,char *ref,char *pat);
void mbx_lsub (MAILSTREAM *stream,char *ref,char *pat);
long mbx_create (MAILSTREAM *stream,char *mailbox);
long mbx_delete (MAILSTREAM *stream,char *mailbox);
long mbx_rename (MAILSTREAM *stream,char *old,char *newname);
long mbx_status (MAILSTREAM *stream,char *mbx,long flags);
MAILSTREAM *mbx_open (MAILSTREAM *stream);
void mbx_close (MAILSTREAM *stream,long options);
void mbx_abort (MAILSTREAM *stream);
void mbx_flags (MAILSTREAM *stream,char *sequence,long flags);
char *mbx_header (MAILSTREAM *stream,unsigned long msgno,unsigned long *length,
		  long flags);
long mbx_text (MAILSTREAM *stream,unsigned long msgno,STRING *bs,long flags);
void mbx_flag (MAILSTREAM *stream,char *sequence,char *flag,long flags);
void mbx_flagmsg (MAILSTREAM *stream,MESSAGECACHE *elt);
long mbx_ping (MAILSTREAM *stream);
void mbx_check (MAILSTREAM *stream);
long mbx_expunge (MAILSTREAM *stream,char *sequence,long options);
void mbx_snarf (MAILSTREAM *stream);
long mbx_copy (MAILSTREAM *stream,char *sequence,char *mailbox,long options);
long mbx_append (MAILSTREAM *stream,char *mailbox,append_t af,void *data);

long mbx_parse (MAILSTREAM *stream);
MESSAGECACHE *mbx_elt (MAILSTREAM *stream,unsigned long msgno,long expok);
unsigned long mbx_read_flags (MAILSTREAM *stream,MESSAGECACHE *elt);
void mbx_update_header (MAILSTREAM *stream);
void mbx_update_status (MAILSTREAM *stream,unsigned long msgno,long flags);
unsigned long mbx_hdrpos (MAILSTREAM *stream,unsigned long msgno,
			  unsigned long *size,char **hdr);
unsigned long mbx_rewrite (MAILSTREAM *stream,unsigned long *reclaimed,
			   long flags);
long mbx_flaglock (MAILSTREAM *stream);

/* MBX mail routines */


/* Driver dispatch used by MAIL */

DRIVER mbxdriver = {
  "mbx",			/* driver name */
  DR_LOCAL|DR_MAIL|DR_CRLF|DR_LOCKING,
				/* driver flags */
  (DRIVER *) NIL,		/* next driver */
  mbx_valid,			/* mailbox is valid for us */
  mbx_parameters,		/* manipulate parameters */
  mbx_scan,			/* scan mailboxes */
  mbx_list,			/* list mailboxes */
  mbx_lsub,			/* list subscribed mailboxes */
  NIL,				/* subscribe to mailbox */
  NIL,				/* unsubscribe from mailbox */
  mbx_create,			/* create mailbox */
  mbx_delete,			/* delete mailbox */
  mbx_rename,			/* rename mailbox */
  mail_status_default,		/* status of mailbox */
  mbx_open,			/* open mailbox */
  mbx_close,			/* close mailbox */
  mbx_flags,			/* fetch message "fast" attributes */
  mbx_flags,			/* fetch message flags */
  NIL,				/* fetch overview */
  NIL,				/* fetch message envelopes */
  mbx_header,			/* fetch message header */
  mbx_text,			/* fetch message body */
  NIL,				/* fetch partial message text */
  NIL,				/* unique identifier */
  NIL,				/* message number */
  mbx_flag,			/* modify flags */
  mbx_flagmsg,			/* per-message modify flags */
  NIL,				/* search for message based on criteria */
  NIL,				/* sort messages */
  NIL,				/* thread messages */
  mbx_ping,			/* ping mailbox to see if still alive */
  mbx_check,			/* check for new messages */
  mbx_expunge,			/* expunge deleted messages */
  mbx_copy,			/* copy messages to another mailbox */
  mbx_append,			/* append string message to mailbox */
  NIL				/* garbage collect stream */
};

				/* prototype stream */
MAILSTREAM mbxproto = {&mbxdriver};

/* MBX mail validate mailbox
 * Accepts: mailbox name
 * Returns: our driver if name is valid, NIL otherwise
 */

DRIVER *mbx_valid (char *name)
{
  char tmp[MAILTMPLEN];
  int fd = mbx_isvalid (NIL,name,tmp,NIL,NIL,NIL);
  if (fd < 0) return NIL;
  close (fd);			/* don't need the fd now */
  return &mbxdriver;
}


/* MBX mail test for valid mailbox
 * Accepts: returned stream with valid mailbox keywords
 *	    mailbox name
 *	    buffer to write file name
 *	    returned lock fd
 *	    returned lock name
 *	    RW flags or NIL for readonly
 * Returns: file descriptor if valid, NIL otherwise
 */

#define MBXISVALIDNOUID 0x1	/* RW, don't do UID action */
#define MBXISVALIDUID 0x2	/* RW, do UID action */

int mbx_isvalid (MAILSTREAM **stream,char *name,char *file,int *ld,char *lock,
		 long flags)
{
  int fd,upd;
  int ret = -1;
  unsigned long i;
  long j,k;
  off_t pos;
  char c,*s,*t,hdr[HDRSIZE];
  struct stat sbuf;
  struct utimbuf times;
  int error = EINVAL;		/* assume invalid argument */
  if (ld) *ld = -1;		/* initially no lock */
				/* if file, get its status */
  if ((s = dummy_file (file,name)) && !stat (s,&sbuf) &&
      ((sbuf.st_mode & S_IFMT) == S_IFREG) &&
      ((fd = open (file,(flags ? O_RDWR : O_RDONLY)|O_BINARY,NIL)) >= 0)) {
    error = -1;			/* assume bogus format */
    if (((((j = read (fd,hdr,HDRSIZE)) == HDRSIZE) && (hdr[0] == '*')) ||
				/* locked, set byte 0 to "*", read rest */
	 ((j < 0) && (lseek (fd,1,L_SET) == 1) &&
	  (read (fd,hdr+1,HDRSIZE-1) == (HDRSIZE-1)) && (hdr[0] = '*'))) &&
	(hdr[1] == 'm') && (hdr[2] == 'b') && (hdr[3] == 'x') &&
	(hdr[4] == '*') && (hdr[5] == '\015') && (hdr[6] == '\012') &&
	isxdigit (hdr[7]) && isxdigit (hdr[8]) && isxdigit (hdr[9]) &&
	isxdigit (hdr[10]) && isxdigit (hdr[11]) && isxdigit (hdr[12]) &&
	isxdigit (hdr[13]) && isxdigit (hdr[14]) && isxdigit (c = hdr[15]) &&
	isxdigit (hdr[16]) && isxdigit (hdr[17]) && isxdigit (hdr[18]) &&
	isxdigit (hdr[19]) && isxdigit (hdr[20]) && isxdigit (hdr[21]) &&
	isxdigit (hdr[22]) && (hdr[23] == '\015') && (hdr[24] == '\012')) {
      ret = fd;			/* mbx format */

      if (stream) {		/* lock if making a mini-stream */
	if (flock (fd,LOCK_SH) ||
	    (flags && ((*ld = lockname (lock,file,LOCK_EX)) < 0))) ret = -1;
				/* reread data now that locked */
	else if (lseek (fd,0,L_SET) ||
		 (read (fd,hdr+1,HDRSIZE-1) != (HDRSIZE-1))) ret = -1;
	else {
	  *stream = (MAILSTREAM *) memset (fs_get (sizeof (MAILSTREAM)),0,
					   sizeof (MAILSTREAM));
	  hdr[15] = '\0';	/* tie off UIDVALIDITY */
	  (*stream)->uid_validity = strtoul (hdr+7,NIL,16);
	  hdr[15] = c;		/* now get UIDLAST */
	  (*stream)->uid_last = strtoul (hdr+15,NIL,16);
				/* parse user flags */
	  for (i = 0, s = hdr + 25;
	       (i < NUSERFLAGS) && (t = strchr (s,'\015')) && (t - s);
	       i++, s = t + 2) {
	    *t = '\0';		/* tie off flag */
	    if (strlen (s) <= MAXUSERFLAG)
	      (*stream)->user_flags[i] = cpystr (s);
	  }
				/* make sure have true UIDLAST */
	  if (flags & MBXISVALIDUID) {
	    for (upd = NIL,pos = 2048, k = 0; pos < sbuf.st_size;
		 pos += (j + k)) {
				/* read header for this message */
	      lseek (fd,pos,L_SET);
	      if ((j = read (fd,hdr,64)) >= 0) {
		hdr[j] = '\0';
		if ((s = strchr (hdr,'\015')) && (s[1] == '\012')) {
		  *s = '\0';
		  k = s + 2 - hdr;
		  if ((s = strchr (hdr,',')) && (j = strtol (s+1,&s,10)) &&
		      (*s == ';') && (s = strchr (s+1,'-'))) {
				/* get UID if there is any */
		    i = strtoul (++s,&t,16);
		    if (!*t && (t == (s + 8)) && (i <= (*stream)->uid_last)) {
		      if (!i) {
			lseek (fd,pos + s - hdr,L_SET);
			sprintf (hdr,"%08lx",++(*stream)->uid_last);
			write (fd,hdr,8);
			upd = T;
		      }
		      continue;
		    }
		  }
		}
		ret = -1;	/* error, give up */
		*stream = mail_close (*stream);
		pos = sbuf.st_size + 1;
		j = k = 0;
	      }
	    }

	    if (upd) {	    /* need to update hdr with new UIDLAST? */
	      lseek (fd,15,L_SET);
	      sprintf (hdr,"%08lx",(*stream)->uid_last);
	      write (fd,hdr,8);
	    }
	  }
	}
      }
    }
    if (ret != fd) close (fd);	/* close the file */
    else lseek (fd,0,L_SET);	/* else rewind to start */
				/* \Marked status? */
    if (sbuf.st_ctime > sbuf.st_atime) {
				/* preserve atime and mtime */
      times.actime = sbuf.st_atime;
      times.modtime = sbuf.st_mtime;
      utime (file,&times);	/* set the times */
    }
  }
				/* in case INBOX but not mbx format */
  else if (((error = errno) == ENOENT) && !compare_cstring (name,"INBOX"))
    error = -1;
  if ((ret < 0) && ld && (*ld >= 0)) {
    unlockfd (*ld,lock);
    *ld = -1;
  }
  errno = error;		/* return as last error */
  return ret;			/* return what we should */
}

/* MBX manipulate driver parameters
 * Accepts: function code
 *	    function-dependent value
 * Returns: function-dependent return value
 */

void *mbx_parameters (long function,void *value)
{
  void *ret = NIL;
  switch ((int) function) {
  case SET_ONETIMEEXPUNGEATPING:
    if (value) ((MBXLOCAL *) ((MAILSTREAM *) value)->local)->expok = T;
  case GET_ONETIMEEXPUNGEATPING:
    if (value) ret = (void *)
      (((MBXLOCAL *) ((MAILSTREAM *) value)->local)->expok ? VOIDT : NIL);
    break;
  }
  return ret;
}


/* MBX mail scan mailboxes
 * Accepts: mail stream
 *	    reference
 *	    pattern to search
 *	    string to scan
 */

void mbx_scan (MAILSTREAM *stream,char *ref,char *pat,char *contents)
{
  if (stream) dummy_scan (NIL,ref,pat,contents);
}


/* MBX mail list mailboxes
 * Accepts: mail stream
 *	    reference
 *	    pattern to search
 */

void mbx_list (MAILSTREAM *stream,char *ref,char *pat)
{
  if (stream) dummy_list (NIL,ref,pat);
}


/* MBX mail list subscribed mailboxes
 * Accepts: mail stream
 *	    reference
 *	    pattern to search
 */

void mbx_lsub (MAILSTREAM *stream,char *ref,char *pat)
{
  if (stream) dummy_lsub (NIL,ref,pat);
}

/* MBX mail create mailbox
 * Accepts: MAIL stream
 *	    mailbox name to create
 * Returns: T on success, NIL on failure
 */

long mbx_create (MAILSTREAM *stream,char *mailbox)
{
  char *s,mbx[MAILTMPLEN],tmp[HDRSIZE];
  long ret = NIL;
  int i,fd;
  if (!(s = dummy_file (mbx,mailbox))) {
    sprintf (mbx,"Can't create %.80s: invalid name",mailbox);
    mm_log (mbx,ERROR);
  }
				/* create underlying file */
  else if (dummy_create (stream,s)) {
				/* done if made directory */
    if ((s = strrchr (s,'\\')) && !s[1]) return T;
    if ((fd = open (mbx,O_WRONLY|O_BINARY,NIL)) < 0) {
      sprintf (tmp,"Can't reopen mailbox node %.80s: %s",mbx,strerror (errno));
      mm_log (tmp,ERROR);
      unlink (mbx);		/* delete the file */
    }
    else {
      memset (tmp,'\0',HDRSIZE);/* initialize header */
      sprintf (s = tmp,"*mbx*\015\012%08lx00000000\015\012",
	       (unsigned long) time (0));
      for (i = 0; i < NUSERFLAGS; ++i)
	sprintf (s += strlen (s),"%s\015\012",
		 (stream && stream->user_flags[i]) ? stream->user_flags[i] :
		 "");
      if (write (fd,tmp,HDRSIZE) != HDRSIZE) {
	sprintf (tmp,"Can't initialize mailbox node %.80s: %s",
		 mbx,strerror (errno));
	mm_log (tmp,ERROR);
	unlink (mbx);		/* delete the file */
      }
      else ret = T;		/* success */
      close (fd);		/* close file */
    }
  }
  return ret;
}


/* MBX mail delete mailbox
 * Accepts: MAIL stream
 *	    mailbox name to delete
 * Returns: T on success, NIL on failure
 */

long mbx_delete (MAILSTREAM *stream,char *mailbox)
{
  return mbx_rename (stream,mailbox,NIL);
}

/* MBX mail rename mailbox
 * Accepts: MAIL stream
 *	    old mailbox name
 *	    new mailbox name (or NIL for delete)
 * Returns: T on success, NIL on failure
 */

long mbx_rename (MAILSTREAM *stream,char *old,char *newname)
{
  long ret = LONGT;
  char c,*s,tmp[MAILTMPLEN],file[MAILTMPLEN],lock[MAILTMPLEN];
  int fd,ld;
  struct stat sbuf;
  if (!dummy_file (file,old) ||
      (newname && (!((s = mailboxfile (tmp,newname)) && *s) ||
		   ((s = strrchr (tmp,'\\')) && !s[1])))) {
    sprintf (tmp,newname ?
	     "Can't rename mailbox %.80s to %.80s: invalid name" :
	     "Can't delete mailbox %.80s: invalid name",
	     old,newname);
    mm_log (tmp,ERROR);
    return NIL;
  }
  else if ((fd = open (file,O_RDWR|O_BINARY,NIL)) < 0) {
    sprintf (tmp,"Can't open mailbox %.80s: %s",old,strerror (errno));
    mm_log (tmp,ERROR);
    return NIL;
  }
				/* get parse/append permission */
  if ((ld = lockname (lock,file,LOCK_EX)) < 0) {
    mm_log ("Unable to lock rename mailbox",ERROR);
    return NIL;
  }
				/* lock out other users */
  if (flock (fd,LOCK_EX|LOCK_NB)) {
    close (fd);			/* couldn't lock, give up on it then */
    sprintf (tmp,"Mailbox %.80s is in use by another process",old);
    mm_log (tmp,ERROR);
    unlockfd (ld,lock);		/* release exclusive parse/append permission */
    return NIL;
  }

  if (newname) {		/* want rename? */
				/* found superior to destination name? */
    if ((s = strrchr (tmp,'\\')) && (s != tmp) &&
	((tmp[1] != ':') || (s != tmp + 2))) {
      c = s[1];			/* remember character after delimiter */
      *s = s[1] = '\0';		/* tie off name at delimiter */
				/* name doesn't exist, create it */
      if (stat (tmp,&sbuf) || ((sbuf.st_mode & S_IFMT) != S_IFDIR)) {
	*s = '\\';		/* restore delimiter */
	if (!dummy_create (stream,tmp)) ret = NIL;
      }
      else *s = '\\';		/* restore delimiter */
      s[1] = c;			/* restore character after delimiter */
    }
    flock (fd,LOCK_UN);		/* release lock on the file */
    close (fd);			/* pacify NTFS */
				/* rename the file */
    if (ret && rename (file,tmp)) {
      sprintf (tmp,"Can't rename mailbox %.80s to %.80s: %s",old,newname,
	       strerror (errno));
      mm_log (tmp,ERROR);
      ret = NIL;		/* set failure */
    }
  }
  else {
    flock (fd,LOCK_UN);		/* release lock on the file */
    close (fd);			/* pacify NTFS */
    if (unlink (file)) {
      sprintf (tmp,"Can't delete mailbox %.80s: %s",old,strerror (errno));
      mm_log (tmp,ERROR);
      ret = NIL;		/* set failure */
    }
  }
  unlockfd (ld,lock);		/* release exclusive parse/append permission */
				/* recreate file if renamed INBOX */
  if (ret && !compare_cstring (old,"INBOX")) mbx_create (NIL,"INBOX");
  return ret;			/* return success */
}

/* MBX mail open
 * Accepts: stream to open
 * Returns: stream on success, NIL on failure
 */

MAILSTREAM *mbx_open (MAILSTREAM *stream)
{
  int fd,ld;
  short silent;
  char tmp[MAILTMPLEN];
  if (!stream) return &mbxproto;/* return prototype for OP_PROTOTYPE call */
  if (stream->local) fatal ("mbx recycle stream");
				/* canonicalize the mailbox name */
  if (!dummy_file (tmp,stream->mailbox)) {
    sprintf (tmp,"Can't open - invalid name: %.80s",stream->mailbox);
    mm_log (tmp,ERROR);
  }
  if (stream->rdonly ||
      (fd = open (tmp,O_RDWR|O_BINARY,NIL)) < 0) {
    if ((fd = open (tmp,O_RDONLY|O_BINARY,NIL)) < 0) {
      sprintf (tmp,"Can't open mailbox: %s",strerror (errno));
      mm_log (tmp,ERROR);
      return NIL;
    }
    else if (!stream->rdonly) {	/* got it, but readonly */
      mm_log ("Can't get write access to mailbox, access is readonly",WARN);
      stream->rdonly = T;
    }
  }

  stream->local = memset (fs_get (sizeof (MBXLOCAL)),NIL,sizeof (MBXLOCAL));
  LOCAL->fd = fd;		/* bind the file */
  LOCAL->ld = -1;		/* no flaglock */
  LOCAL->buf = (char *) fs_get (CHUNKSIZE);
  LOCAL->buflen = CHUNKSIZE - 1;
				/* note if an INBOX or not */
  stream->inbox = !compare_cstring (stream->mailbox,"INBOX");
  fs_give ((void **) &stream->mailbox);
  stream->mailbox = cpystr (tmp);
				/* get parse/append permission */
  if ((ld = lockname (tmp,stream->mailbox,LOCK_EX)) < 0) {
    mm_log ("Unable to lock open mailbox",ERROR);
    return NIL;
  }
  flock (LOCAL->fd,LOCK_SH);	/* lock the file */
  unlockfd (ld,tmp);		/* release shared parse permission */
  LOCAL->filesize = HDRSIZE;	/* initialize parsed file size */
  LOCAL->filetime = 0;		/* time not set up yet */
  LOCAL->expok = LOCAL->flagcheck = NIL;
  stream->sequence++;		/* bump sequence number */
				/* parse mailbox */
  stream->nmsgs = stream->recent = 0;
  silent = stream->silent;	/* defer events */
  stream->silent = T;
  if (mbx_ping (stream) && !stream->nmsgs)
    mm_log ("Mailbox is empty",(long) NIL);
  stream->silent = silent;	/* now notify upper level */
  mail_exists (stream,stream->nmsgs);
  mail_recent (stream,stream->recent);
  if (!LOCAL) return NIL;	/* failure if stream died */
  stream->perm_seen = stream->perm_deleted = stream->perm_flagged =
    stream->perm_answered = stream->perm_draft = stream->rdonly ? NIL : T;
  stream->perm_user_flags = stream->rdonly ? NIL : 0xffffffff;
  stream->kwd_create = (stream->user_flags[NUSERFLAGS-1] || stream->rdonly) ?
    NIL : T;			/* can we create new user flags? */
  return stream;		/* return stream to caller */
}

/* MBX mail close
 * Accepts: MAIL stream
 *	    close options
 */

void mbx_close (MAILSTREAM *stream,long options)
{
  if (stream && LOCAL) {	/* only if a file is open */
    int silent = stream->silent;
    stream->silent = T;		/* note this stream is dying */
				/* do an expunge if requested */
    if (options & CL_EXPUNGE) mbx_expunge (stream,NIL,NIL);
    else {			/* otherwise do a checkpoint to purge */
      LOCAL->expok = T;		/*  possible expunged messages */
      mbx_ping (stream);
    }
    stream->silent = silent;	/* restore previous status */
    mbx_abort (stream);
  }
}


/* MBX mail abort stream
 * Accepts: MAIL stream
 */

void mbx_abort (MAILSTREAM *stream)
{
  if (stream && LOCAL) {	/* only if a file is open */
    flock (LOCAL->fd,LOCK_UN);	/* unlock local file */
    close (LOCAL->fd);		/* close the local file */
				/* free local text buffer */
    if (LOCAL->buf) fs_give ((void **) &LOCAL->buf);
				/* nuke the local data */
    fs_give ((void **) &stream->local);
    stream->dtb = NIL;		/* log out the DTB */
  }
}


/* MBX mail fetch flags
 * Accepts: MAIL stream
 *	    sequence
 *	    option flags
 * Sniffs at file to see if some other process changed the flags
 */

void mbx_flags (MAILSTREAM *stream,char *sequence,long flags)
{
  MESSAGECACHE *elt;
  unsigned long i;
  if (mbx_ping (stream) &&	/* ping mailbox, get new status for messages */
      ((flags & FT_UID) ? mail_uid_sequence (stream,sequence) :
       mail_sequence (stream,sequence)))
    for (i = 1; i <= stream->nmsgs; i++) 
      if ((elt = mail_elt (stream,i))->sequence && !elt->valid)
	mbx_elt (stream,i,NIL);
}

/* MBX mail fetch message header
 * Accepts: MAIL stream
 *	    message # to fetch
 *	    pointer to returned header text length
 *	    option flags
 * Returns: message header in RFC822 format
 */

char *mbx_header (MAILSTREAM *stream,unsigned long msgno,unsigned long *length,
		  long flags)
{
  unsigned long i;
  char *s;
  *length = 0;			/* default to empty */
  if (flags & FT_UID) return "";/* UID call "impossible" */
				/* get header position, possibly header */
  i = mbx_hdrpos (stream,msgno,length,&s);
  if (!s) {			/* mbx_hdrpos() returned header? */
    lseek (LOCAL->fd,i,L_SET);	/* no, get to header position */
				/* is buffer big enough? */
    if (*length > LOCAL->buflen) {
      fs_give ((void **) &LOCAL->buf);
      LOCAL->buf = (char *) fs_get ((LOCAL->buflen = *length) + 1);
    }
				/* slurp the data */
    read (LOCAL->fd,s = LOCAL->buf,*length);
  }
  s[*length] = '\0';		/* tie off string */
  return s;
}

/* MBX mail fetch message text (body only)
 * Accepts: MAIL stream
 *	    message # to fetch
 *	    pointer to returned header text length
 *	    option flags
 * Returns: T on success, NIL on failure
 */

long mbx_text (MAILSTREAM *stream,unsigned long msgno,STRING *bs,long flags)
{
  FDDATA d;
  unsigned long i,j;
  MESSAGECACHE *elt;
				/* UID call "impossible" */
  if (flags & FT_UID) return NIL;
				/* get message status */
  elt = mbx_elt (stream,msgno,NIL);
				/* if message not seen */
  if (!(flags & FT_PEEK) && !elt->seen && mbx_flaglock (stream)) {
    elt->seen = T;		/* mark message as seen */
				/* recalculate status */
    mbx_update_status (stream,msgno,NIL);
    mm_flags (stream,msgno);
				/* update flags */
    mbx_flag (stream,NIL,NIL,NIL);
  }
  if (!LOCAL) return NIL;	/* mbx_flaglock() could have aborted */
				/* find header position */
  i = mbx_hdrpos (stream,msgno,&j,NIL);
  d.fd = LOCAL->fd;		/* set up file descriptor */
  d.pos = i + j;
  d.chunk = LOCAL->buf;	/* initial buffer chunk */
  d.chunksize = CHUNKSIZE;
  INIT (bs,fd_string,&d,elt->rfc822_size - j);
  return LONGT;			/* success */
}

/* MBX mail modify flags
 * Accepts: MAIL stream
 *	    sequence
 *	    flag(s)
 *	    option flags
 * Unlocks flag lock
 */

void mbx_flag (MAILSTREAM *stream,char *sequence,char *flag,long flags)
{
  struct utimbuf times;
  struct stat sbuf;
				/* make sure the update takes */
  if (!stream->rdonly && LOCAL && (LOCAL->fd >= 0) && (LOCAL->ld >= 0)) {
    fsync (LOCAL->fd);
    fstat (LOCAL->fd,&sbuf);	/* get current write time */
    times.modtime = LOCAL->filetime = sbuf.st_mtime;
				/* update header */
    if ((LOCAL->ffuserflag < NUSERFLAGS) &&
	stream->user_flags[LOCAL->ffuserflag]) mbx_update_header (stream);
    times.actime = time (0);	/* make sure read comes after all that */
    utime (stream->mailbox,&times);
  }
  if (LOCAL->ld >= 0) {		/* unlock now */
    unlockfd (LOCAL->ld,LOCAL->lock);
    LOCAL->ld = -1;
  }
}


/* MBX mail per-message modify flags
 * Accepts: MAIL stream
 *	    message cache element
 */

void mbx_flagmsg (MAILSTREAM *stream,MESSAGECACHE *elt)
{
  if (mbx_flaglock (stream)) mbx_update_status (stream,elt->msgno,NIL);
}

/* MBX mail ping mailbox
 * Accepts: MAIL stream
 * Returns: T if stream still alive, NIL if not
 */

long mbx_ping (MAILSTREAM *stream)
{
  unsigned long i,pos;
  long ret = NIL;
  int ld;
  char lock[MAILTMPLEN];
  MESSAGECACHE *elt;
  struct stat sbuf;
  if (stream && LOCAL) {	/* only if stream already open */
    ret = LONGT;		/* assume OK */
    fstat (LOCAL->fd,&sbuf);	/* get current file poop */
				/* allow expunge if permitted at ping */
    if (mail_parameters (NIL,GET_EXPUNGEATPING,NIL)) LOCAL->expok = T;
				/* if external modification */
    if (LOCAL->filetime && (LOCAL->filetime < sbuf.st_mtime))
      LOCAL->flagcheck = T;	/* upgrade to flag checking */
				/* new mail or flagcheck handling needed? */
    if (((sbuf.st_size - LOCAL->filesize) || LOCAL->flagcheck ||
	 !stream->nmsgs) &&
	((ld = lockname (lock,stream->mailbox,LOCK_EX)) >= 0)) {
      if (!LOCAL->flagcheck) ret = mbx_parse (stream);
				/* sweep mailbox for changed message status */
      else if (ret = mbx_parse (stream)) {
	unsigned long recent = 0;
	LOCAL->filetime = sbuf.st_mtime;
	for (i = 1; i <= stream->nmsgs; )
	  if (elt = mbx_elt (stream,i,LOCAL->expok)) {
	    if (elt->recent) ++recent;
	    ++i;
	  }
	mail_recent (stream,recent);
	LOCAL->flagcheck = NIL;	/* got all the updates */
      }
      unlockfd (ld,lock);	/* release shared parse/append permission */
    }
    if (ret) {			/* must still be alive */
      if (!LOCAL->expunged)	/* look for holes if none known yet */
	for (i = 1, pos = HDRSIZE;
	     !LOCAL->expunged && (i <= stream->nmsgs);
	     i++, pos += elt->private.special.text.size + elt->rfc822_size)
	  if ((elt = mail_elt (stream,i))->private.special.offset != pos)
	    LOCAL->expunged = T;/* found a hole */
				/* burp any holes */
      if (LOCAL->expunged && !stream->rdonly) {
	if (mbx_rewrite (stream,&i,NIL)) fatal ("expunge on check");
	if (i) {		/* any space reclaimed? */
	  LOCAL->expunged = NIL;/* no more pending expunge */
	  sprintf (LOCAL->buf,"Reclaimed %lu bytes of expunged space",i);
	  mm_log (LOCAL->buf,(long) NIL);
	}
      }
      LOCAL->expok = NIL;	/* no more expok */
    }
  }
  return ret;			/* return result of the parse */
}

/* MBX mail check mailbox (reparses status too)
 * Accepts: MAIL stream
 */

void mbx_check (MAILSTREAM *stream)
{
  if (LOCAL) LOCAL->expok = T;	/* mark that a check is desired */
  if (mbx_ping (stream)) mm_log ("Check completed",(long) NIL);
}


/* MBX mail expunge mailbox
 * Accepts: MAIL stream
 *	    sequence to expunge if non-NIL
 *	    expunge options
 * Returns: T if success, NIL if failure
 */

long mbx_expunge (MAILSTREAM *stream,char *sequence,long options)
{
  long ret;
  unsigned long nexp,reclaimed;
  if (ret = sequence ? ((options & EX_UID) ?
			mail_uid_sequence (stream,sequence) :
			mail_sequence (stream,sequence)) : LONGT) {
    if (!mbx_ping (stream));	/* do nothing if stream dead */
    else if (stream->rdonly)	/* won't do on readonly files! */
      mm_log ("Expunge ignored on readonly mailbox",WARN);
				/* if expunged any messages */
    else if (nexp = mbx_rewrite (stream,&reclaimed,sequence ? -1 : 1)) {
      sprintf (LOCAL->buf,"Expunged %lu messages",nexp);
      mm_log (LOCAL->buf,(long) NIL);
    }
    else if (reclaimed) {	 /* or if any prior expunged space reclaimed */
      sprintf (LOCAL->buf,"Reclaimed %lu bytes of expunged space",reclaimed);
      mm_log (LOCAL->buf,(long) NIL);
    }
    else mm_log ("No messages deleted, so no update needed",(long) NIL);
  }
  return ret;
}

/* MBX mail copy message(s)
 * Accepts: MAIL stream
 *	    sequence
 *	    destination mailbox
 *	    copy options
 * Returns: T if success, NIL if failed
 */

long mbx_copy (MAILSTREAM *stream,char *sequence,char *mailbox,long options)
{
  struct stat sbuf;
  struct utimbuf times;
  MESSAGECACHE *elt;
  unsigned long i,j,k,m;
  long ret = LONGT;
  int fd,ld;
  char *s,*t,file[MAILTMPLEN],lock[MAILTMPLEN];
  mailproxycopy_t pc =
    (mailproxycopy_t) mail_parameters (stream,GET_MAILPROXYCOPY,NIL);
  copyuid_t cu = (copyuid_t) mail_parameters (NIL,GET_COPYUID,NIL);
  SEARCHSET *source = cu ? mail_newsearchset () : NIL;
  SEARCHSET *dest = cu ? mail_newsearchset () : NIL;
  MAILSTREAM *dstream = NIL;
  if (!((options & CP_UID) ? mail_uid_sequence (stream,sequence) :
	mail_sequence (stream,sequence))) return NIL;
				/* make sure valid mailbox */
  if ((fd = mbx_isvalid (&dstream,mailbox,file,&ld,lock,
			 cu ? MBXISVALIDUID : MBXISVALIDNOUID)) < 0)
    switch (errno) {
    case ENOENT:		/* no such file? */
      mm_notify (stream,"[TRYCREATE] Must create mailbox before copy",NIL);
      return NIL;
    case EACCES:		/* file protected */
      sprintf (LOCAL->buf,"Can't access destination: %.80s",mailbox);
      MM_LOG (LOCAL->buf,ERROR);
      return NIL;
    case EINVAL:
      if (pc) return (*pc) (stream,sequence,mailbox,options);
      sprintf (LOCAL->buf,"Invalid MBX-format mailbox name: %.80s",mailbox);
      mm_log (LOCAL->buf,ERROR);
      return NIL;
    default:
      if (pc) return (*pc) (stream,sequence,mailbox,options);
      sprintf (LOCAL->buf,"Not a MBX-format mailbox: %.80s",mailbox);
      mm_log (LOCAL->buf,ERROR);
      return NIL;
    }
				/* got file? */  
  if ((fd = open (dummy_file (file,mailbox),O_RDWR|O_CREAT|O_BINARY,
		  S_IREAD|S_IWRITE)) < 0) {
    sprintf (LOCAL->buf,"Unable to open copy mailbox: %s",strerror (errno));
    mm_log (LOCAL->buf,ERROR);
    return NIL;
  }
  mm_critical (stream);		/* go critical */
  fstat (fd,&sbuf);		/* get current file size */
  lseek (fd,sbuf.st_size,L_SET);/* move to end of file */

				/* for each requested message */
  for (i = 1; ret && (i <= stream->nmsgs); i++) 
    if ((elt = mail_elt (stream,i))->sequence) {
      lseek (LOCAL->fd,elt->private.special.offset +
	     elt->private.special.text.size,L_SET);
      mail_date(LOCAL->buf,elt);/* build target header */
				/* get target keyword mask */
      for (j = elt->user_flags, k = 0; j; )
	if (s = stream->user_flags[find_rightmost_bit (&j)])
	  for (m = 0; (m < NUSERFLAGS) && (t = dstream->user_flags[m]); m++)
	    if (!compare_cstring (s,t) && (k |= 1 << m)) break;
      sprintf (LOCAL->buf+strlen(LOCAL->buf),",%lu;%08lx%04x-%08lx\015\012",
	       elt->rfc822_size,k,(unsigned)
	       ((fSEEN * elt->seen) + (fDELETED * elt->deleted) +
		(fFLAGGED * elt->flagged) + (fANSWERED * elt->answered) +
		(fDRAFT * elt->draft)),cu ? ++dstream->uid_last : 0);
				/* write target header */
      if (ret = (write (fd,LOCAL->buf,strlen (LOCAL->buf)) > 0)) {
	for (k = elt->rfc822_size; ret && (j = min (k,LOCAL->buflen)); k -= j){
	  read (LOCAL->fd,LOCAL->buf,j);
	  ret = write (fd,LOCAL->buf,j) >= 0;
	}
	if (cu) {		/* need to pass back new UID? */
	  mail_append_set (source,mail_uid (stream,i));
	  mail_append_set (dest,dstream->uid_last);
	}
      }
    }

				/* make sure all the updates take */
  if (!(ret && (ret = !fsync (fd)))) {
    sprintf (LOCAL->buf,"Unable to write message: %s",strerror (errno));
    mm_log (LOCAL->buf,ERROR);
    ftruncate (fd,sbuf.st_size);
  }
  if (cu && ret) {		/* return sets if doing COPYUID */
    (*cu) (stream,mailbox,dstream->uid_validity,source,dest);
    lseek (fd,15,L_SET);	/* update UIDLAST */
    sprintf (LOCAL->buf,"%08lx",dstream->uid_last);
    write (fd,LOCAL->buf,8);
  }
  else {			/* flush any sets we may have built */
    mail_free_searchset (&source);
    mail_free_searchset (&dest);
  }
				/* set atime to now-1 if successful copy */
  if (ret) times.actime = time (0) - 1;
				/* else preserved \Marked status */
  else times.actime = (sbuf.st_ctime > sbuf.st_atime) ?
	 sbuf.st_atime : time (0);
  times.modtime = sbuf.st_mtime;/* preserve mtime */
  utime (file,&times);		/* set the times */
  close (fd);			/* close the file */
  mm_nocritical (stream);	/* release critical */
  unlockfd (ld,lock);		/* release exclusive parse/append permission */
				/* delete all requested messages */
  if (ret && (options & CP_MOVE) && mbx_flaglock (stream)) {
    for (i = 1; i <= stream->nmsgs; i++) if (mail_elt (stream,i)->sequence) {
				/* mark message deleted */
      mbx_elt (stream,i,NIL)->deleted = T;
				/* recalculate status */
      mbx_update_status (stream,i,NIL);
    }
				/* update flags */
    mbx_flag (stream,NIL,NIL,NIL);
  }
  if (dstream != stream) mail_close (dstream);
  return ret;
}

/* MBX mail append message from stringstruct
 * Accepts: MAIL stream
 *	    destination mailbox
 *	    append callback
 *	    data for callback
 * Returns: T if append successful, else NIL
 */

long mbx_append (MAILSTREAM *stream,char *mailbox,append_t af,void *data)
{
  struct stat sbuf;
  int fd,ld;
  char *flags,*date,tmp[MAILTMPLEN],file[MAILTMPLEN],lock[MAILTMPLEN];
  struct utimbuf times;
  FILE *df;
  MESSAGECACHE elt;
  long f;
  unsigned long i,uf;
  STRING *message;
  long ret = NIL;
  MAILSTREAM *dstream = NIL;
  appenduid_t au = (appenduid_t) mail_parameters (NIL,GET_APPENDUID,NIL);
  SEARCHSET *dst = au ? mail_newsearchset () : NIL;
				/* make sure valid mailbox */
				/* make sure valid mailbox */
  if ((fd = mbx_isvalid (&dstream,mailbox,file,&ld,lock,
			 au ? MBXISVALIDUID : MBXISVALIDNOUID)) < 0)
    switch (errno) {
    case ENOENT:		/* no such file? */
      if (compare_cstring (mailbox,"INBOX")) {
	mm_notify (stream,"[TRYCREATE] Must create mailbox before append",NIL);
	return NIL;
      }
				/* can create INBOX here */
      mbx_create (dstream = stream ? stream : &mbxproto,"INBOX");
      if ((fd = mbx_isvalid (&dstream,mailbox,file,&ld,lock,
			     au ? MBXISVALIDUID : MBXISVALIDNOUID)) < 0)
	break;
    case EACCES:		/* file protected */
      sprintf (tmp,"Can't access destination: %.80s",mailbox);
      MM_LOG (tmp,ERROR);
      return NIL;
    case EINVAL:
      sprintf (tmp,"Invalid MBX-format mailbox name: %.80s",mailbox);
      mm_log (tmp,ERROR);
      return NIL;
    default:
      sprintf (tmp,"Not a MBX-format mailbox: %.80s",mailbox);
      mm_log (tmp,ERROR);
      return NIL;
    }

				/* get first message */
  if (!(*af) (dstream,data,&flags,&date,&message)) close (fd);
  else if (!(df = fdopen (fd,"r+b"))) {
    MM_LOG ("Unable to reopen append mailbox",ERROR);
    close (fd);
  }
  else {
    mm_critical (dstream);	/* go critical */
    fstat (fd,&sbuf);		/* get current file size */
    fseek (df,sbuf.st_size,SEEK_SET);
    errno = 0;
    for (ret = LONGT; ret && message; ) {
      if (!SIZE (message)) {	/* guard against zero-length */
	mm_log ("Append of zero-length message",ERROR);
	ret = NIL;
	break;
      }
      f = mail_parse_flags (dstream,flags,&uf);
      if (date) {		/* parse date if given */
	if (!mail_parse_date (&elt,date)) {
	  sprintf (tmp,"Bad date in append: %.80s",date);
	  mm_log (tmp,ERROR);
	  ret = NIL;		/* mark failure */
	  break;
	}
	mail_date (tmp,&elt);	/* write preseved date */
      }
      else internal_date (tmp);	/* get current date in IMAP format */
				/* write header */
      if (fprintf (df,"%s,%lu;%08lx%04lx-%08lx\015\012",tmp,i = SIZE (message),
		   uf,(unsigned long) f,au ? ++dstream->uid_last : 0) < 0)
	ret = NIL;
      else {			/* write message */
	size_t j;
	if (!message->cursize) SETPOS (message,GETPOS (message));
	while (i && (j = fwrite (message->curpos,1,message->cursize,df))) {
	  i -= j;
	  SETPOS (message,GETPOS (message) + j);
	}
				/* get next message */
	if (i || !(*af) (dstream,data,&flags,&date,&message)) ret = NIL;
	else if (au) mail_append_set (dst,dstream->uid_last);
      }
    }

				/* if error... */
    if (!ret || (fflush (df) == EOF)) {
				/* revert file */
      ftruncate (fd,sbuf.st_size);
      close (fd);		/* make sure fclose() doesn't corrupt us */
      if (errno) {
	sprintf (tmp,"Message append failed: %s",strerror (errno));
	mm_log (tmp,ERROR);
      }
      ret = NIL;
    }
    if (au && ret) {		/* return sets if doing APPENDUID */
      (*au) (mailbox,dstream->uid_validity,dst);
      fseek (df,15,SEEK_SET);	/* update UIDLAST */
      fprintf (df,"%08lx",dstream->uid_last);
    }
    else mail_free_searchset (&dst);
    if (ret) times.actime = time (0) - 1;
				/* else preserve \Marked status */
    else times.actime = (sbuf.st_ctime > sbuf.st_atime) ?
	   sbuf.st_atime : time (0);
				/* preserve mtime */
    times.modtime = sbuf.st_mtime;
    utime (file,&times);	/* set the times */
    fclose (df);		/* close the file */
    mm_nocritical (dstream);	/* release critical */
  }
  unlockfd (ld,lock);		/* release exclusive parse/append permission */
  if (dstream != stream) mail_close (dstream);
  return ret;
}

/* Internal routines */


/* MBX mail parse mailbox
 * Accepts: MAIL stream
 * Returns: T if parse OK
 *	    NIL if failure, stream aborted
 */

long mbx_parse (MAILSTREAM *stream)
{
  struct stat sbuf;
  MESSAGECACHE *elt = NIL;
  unsigned char c,*s,*t,*x;
  char tmp[MAILTMPLEN];
  unsigned long i,j,k,m;
  off_t curpos = LOCAL->filesize;
  unsigned long nmsgs = stream->nmsgs;
  unsigned long recent = stream->recent;
  unsigned long lastuid = 0;
  short dirty = NIL;
  short added = NIL;
  short silent = stream->silent;
  short uidwarn = T;
  fstat (LOCAL->fd,&sbuf);	/* get status */
  if (sbuf.st_size < curpos) {	/* sanity check */
    sprintf (tmp,"Mailbox shrank from %lu to %lu!",
	     (unsigned long) curpos,(unsigned long) sbuf.st_size);
    mm_log (tmp,ERROR);
    mbx_abort (stream);
    return NIL;
  }
  lseek (LOCAL->fd,0,L_SET);	/* rewind file */
				/* read internal header */
  read (LOCAL->fd,LOCAL->buf,HDRSIZE);
  LOCAL->buf[HDRSIZE] = '\0';	/* tie off header */
  c = LOCAL->buf[15];		/* save first character of last UID */
  LOCAL->buf[15] = '\0';
				/* parse UID validity */
  stream->uid_validity = strtoul (LOCAL->buf + 7,NIL,16);
  LOCAL->buf[15] = c;		/* restore first character of last UID */
				/* parse last UID */
  i = strtoul (LOCAL->buf + 15,NIL,16);
  stream->uid_last = stream->rdonly ? max (i,stream->uid_last) : i;
				/* parse user flags */
  for (i = 0, s = LOCAL->buf + 25;
       (i < NUSERFLAGS) && (t = strchr (s,'\015')) && (t - s);
       i++, s = t + 2) {
    *t = '\0';			/* tie off flag */
    if (!stream->user_flags[i] && (strlen (s) <= MAXUSERFLAG))
      stream->user_flags[i] = cpystr (s);
  }
  LOCAL->ffuserflag = (int) i;	/* first free user flag */

  stream->silent = T;		/* don't pass up mm_exists() events yet */
  while (sbuf.st_size - curpos){/* while there is stuff to parse */
				/* get to that position in the file */
    lseek (LOCAL->fd,curpos,L_SET);
    if ((i = read (LOCAL->fd,LOCAL->buf,64)) <= 0) {
      sprintf (tmp,"Unable to read internal header at %lu, size = %lu: %s",
	       (unsigned long) curpos,(unsigned long) sbuf.st_size,
	       i ? strerror (errno) : "no data read");
      mm_log (tmp,ERROR);
      mbx_abort (stream);
      return NIL;
    }
    LOCAL->buf[i] = '\0';	/* tie off buffer just in case */
    if (!((s = strchr (LOCAL->buf,'\015')) && (s[1] == '\012'))) {
      sprintf (tmp,"Unable to find CRLF at %lu in %lu bytes, text: %.80s",
	       (unsigned long) curpos,i,(char *) LOCAL->buf);
      mm_log (tmp,ERROR);
      mbx_abort (stream);
      return NIL;
    }
    *s = '\0';			/* tie off header line */
    i = (s + 2) - LOCAL->buf;	/* note start of text offset */
    if (!((s = strchr (LOCAL->buf,',')) && (t = strchr (s+1,';')))) {
      sprintf (tmp,"Unable to parse internal header at %lu: %.80s",
	       (unsigned long) curpos,(char *) LOCAL->buf);
      mm_log (tmp,ERROR);
      mbx_abort (stream);
      return NIL;
    }
    if (!(isxdigit (t[1]) && isxdigit (t[2]) && isxdigit (t[3]) &&
	  isxdigit (t[4]) && isxdigit (t[5]) && isxdigit (t[6]) &&
	  isxdigit (t[7]) && isxdigit (t[8]) && isxdigit (t[9]) &&
	  isxdigit (t[10]) && isxdigit (t[11]) && isxdigit (t[12]))) {
      sprintf (tmp,"Unable to parse message flags at %lu: %.80s",
	       (unsigned long) curpos,(char *) LOCAL->buf);
      mm_log (tmp,ERROR);
      mbx_abort (stream);
      return NIL;
    }
    if ((t[13] != '-') || t[22] ||
	!(isxdigit (t[14]) && isxdigit (t[15]) && isxdigit (t[16]) &&
	  isxdigit (t[17]) && isxdigit (t[18]) && isxdigit (t[19]) &&
	  isxdigit (t[20]) && isxdigit (t[21]))) {
      sprintf (tmp,"Unable to parse message UID at %lu: %.80s",
	       (unsigned long) curpos,(char *) LOCAL->buf);
      mm_log (tmp,ERROR);
      mbx_abort (stream);
      return NIL;
    }

    *s++ = '\0'; *t++ = '\0';	/* break up fields */
				/* get message size */
    if (!(j = strtoul (s,(char **) &x,10)) && (!(x && *x))) {
      sprintf (tmp,"Unable to parse message size at %lu: %.80s,%.80s;%.80s",
	       (unsigned long) curpos,(char *) LOCAL->buf,(char *) s,
	       (char *) t);
      mm_log (tmp,ERROR);
      mbx_abort (stream);
      return NIL;
    }
				/* make sure didn't run off end of file */
    if (((off_t) (curpos + i + j)) > sbuf.st_size) {
      sprintf (tmp,"Last message (at %lu) runs past end of file (%lu > %lu)",
	       (unsigned long) curpos,(unsigned long) (curpos + i + j),
	       (unsigned long) sbuf.st_size);
      mm_log (tmp,ERROR);
      mbx_abort (stream);
      return NIL;
    }
				/* parse UID */
    if ((m = strtoul (t+13,NIL,16)) &&
	((m <= lastuid) || (m > stream->uid_last))) {
      if (uidwarn) {
	sprintf (tmp,"Invalid UID %08lx in message %lu, rebuilding UIDs",
		 m,nmsgs+1);
	mm_log (tmp,WARN);
	uidwarn = NIL;
				/* restart UID validity */
	stream->uid_validity = (unsigned long) time (0);
      }
      m = 0;			/* lose this UID */
      dirty = T;		/* mark dirty, set new lastuid */
      stream->uid_last = lastuid;
    }

    t[12] = '\0';		/* parse system flags */
    if ((k = strtoul (t+8,NIL,16)) & fEXPUNGED) {
      if (m) lastuid = m;	/* expunge message, update last UID seen */
      else {			/* no UID assigned? */
	lastuid = ++stream->uid_last;
	dirty = T;
      }
    }
    else {			/* not expunged, swell the cache */
      added = T;		/* note that a new message was added */
      mail_exists (stream,++nmsgs);
				/* instantiate an elt for this message */
      (elt = mail_elt (stream,nmsgs))->valid = T;
				/* parse the date */
      if (!mail_parse_date (elt,LOCAL->buf)) {
	sprintf (tmp,"Unable to parse message date at %lu: %.80s",
		 (unsigned long) curpos,(char *) LOCAL->buf);
	mm_log (tmp,ERROR);
	mbx_abort (stream);
	return NIL;
      }
				/* note file offset of header */
      elt->private.special.offset = curpos;
				/* and internal header size */
      elt->private.special.text.size = i;
				/* header size not known yet */
      elt->private.msg.header.text.size = 0;
      elt->rfc822_size = j;	/* note message size */
				/* calculate system flags */
      if (k & fSEEN) elt->seen = T;
      if (k & fDELETED) elt->deleted = T;
      if (k & fFLAGGED) elt->flagged = T;
      if (k & fANSWERED) elt->answered = T;
      if (k & fDRAFT) elt->draft = T;
      t[8] = '\0';		/* get user flags value */
      elt->user_flags = strtoul (t,NIL,16);
				/* UID already assigned? */
      if (!(elt->private.uid = m) || !(k & fOLD)) {
	elt->recent = T;	/* no, mark as recent */
	++recent;		/* count up a new recent message */
	dirty = T;		/* and must rewrite header */
				/* assign new UID */
	if (!elt->private.uid) elt->private.uid = ++stream->uid_last;
	mbx_update_status (stream,elt->msgno,NIL);
      }
				/* update last parsed UID */
      lastuid = elt->private.uid;
    }
    curpos += i + j;		/* update position */
  }

  if (dirty && !stream->rdonly){/* update header */
    mbx_update_header (stream);
    fsync (LOCAL->fd);		/* make sure all the UID updates take */
  }
				/* update parsed file size and time */
  LOCAL->filesize = sbuf.st_size;
  fstat (LOCAL->fd,&sbuf);	/* get status again to ensure time is right */
  LOCAL->filetime = sbuf.st_mtime;
  if (added && !stream->rdonly){/* make sure atime updated */
    struct utimbuf times;
    times.actime = time (0);
    times.modtime = LOCAL->filetime;
    utime (stream->mailbox,&times);
  }
  stream->silent = silent;	/* can pass up events now */
  mail_exists (stream,nmsgs);	/* notify upper level of new mailbox size */
  mail_recent (stream,recent);	/* and of change in recent messages */
  return LONGT;			/* return the winnage */
}

/* MBX get cache element with status updating from file
 * Accepts: MAIL stream
 *	    message number
 *	    expunge OK flag
 * Returns: cache element
 */

MESSAGECACHE *mbx_elt (MAILSTREAM *stream,unsigned long msgno,long expok)
{
  MESSAGECACHE *elt = mail_elt (stream,msgno);
  struct {			/* old flags */
    unsigned int seen : 1;
    unsigned int deleted : 1;
    unsigned int flagged : 1;
    unsigned int answered : 1;
    unsigned int draft : 1;
    unsigned long user_flags;
  } old;
  old.seen = elt->seen; old.deleted = elt->deleted; old.flagged = elt->flagged;
  old.answered = elt->answered; old.draft = elt->draft;
  old.user_flags = elt->user_flags;
				/* get new flags */
  if (mbx_read_flags (stream,elt) && expok) {
    mail_expunged (stream,elt->msgno);
    return NIL;			/* return this message was expunged */
  }
  if ((old.seen != elt->seen) || (old.deleted != elt->deleted) ||
      (old.flagged != elt->flagged) || (old.answered != elt->answered) ||
      (old.draft != elt->draft) || (old.user_flags != elt->user_flags))
    mm_flags (stream,msgno);	/* let top level know */
  return elt;
}

/* MBX read flags from file
 * Accepts: MAIL stream
 *	    cache element
 * Returns: non-NIL if message expunged
 */

unsigned long mbx_read_flags (MAILSTREAM *stream,MESSAGECACHE *elt)
{
  unsigned long i;
  struct stat sbuf;
  fstat (LOCAL->fd,&sbuf);	/* get status */
				/* make sure file size is good */
  if (sbuf.st_size < LOCAL->filesize) {
    sprintf (LOCAL->buf,"Mailbox shrank from %lu to %lu in flag read!",
	     (unsigned long) LOCAL->filesize,(unsigned long) sbuf.st_size);
    fatal (LOCAL->buf);
  }
				/* set the seek pointer */
  lseek (LOCAL->fd,(off_t) elt->private.special.offset +
	 elt->private.special.text.size - 24,L_SET);
				/* read the new flags */
  if (read (LOCAL->fd,LOCAL->buf,14) < 0) {
    sprintf (LOCAL->buf,"Unable to read new status: %s",strerror (errno));
    fatal (LOCAL->buf);
  }
  if ((LOCAL->buf[0] != ';') || (LOCAL->buf[13] != '-')) {
    LOCAL->buf[14] = '\0';	/* tie off buffer for error message */
    sprintf (LOCAL->buf+50,"Invalid flags for message %lu (%lu %lu): %s",
	     elt->msgno,elt->private.special.offset,
	     elt->private.special.text.size,(char *) LOCAL->buf);
    fatal (LOCAL->buf+50);
  }
  LOCAL->buf[13] = '\0';	/* tie off buffer */
				/* calculate system flags */
  i = strtoul (LOCAL->buf+9,NIL,16);
  elt->seen = i & fSEEN ? T : NIL;
  elt->deleted = i & fDELETED ? T : NIL;
  elt->flagged = i & fFLAGGED ? T : NIL;
  elt->answered = i & fANSWERED ? T : NIL;
  elt->draft = i & fDRAFT ? T : NIL;
  LOCAL->expunged |= i & fEXPUNGED ? T : NIL;
  LOCAL->buf[9] = '\0';		/* tie off flags */
				/* get user flags value */
  elt->user_flags = strtoul (LOCAL->buf+1,NIL,16);
  elt->valid = T;		/* have valid flags now */
  return i & fEXPUNGED;
}

/* MBX update header
 * Accepts: MAIL stream
 */

#define NTKLUDGEOFFSET 7

void mbx_update_header (MAILSTREAM *stream)
{
  int i;
  char *s = LOCAL->buf;
  memset (s,'\0',HDRSIZE);	/* initialize header */
  sprintf (s,"*mbx*\015\012%08lx%08lx\015\012",
	   stream->uid_validity,stream->uid_last);
  for (i = 0; (i < NUSERFLAGS) && stream->user_flags[i]; ++i)
    sprintf (s += strlen (s),"%s\015\012",stream->user_flags[i]);
  LOCAL->ffuserflag = i;	/* first free user flag */
				/* can we create more user flags? */
  stream->kwd_create = (i < NUSERFLAGS) ? T : NIL;
				/* write reserved lines */
  while (i++ < NUSERFLAGS) strcat (s,"\015\012");
  while (T) {			/* rewind file */
    lseek (LOCAL->fd,NTKLUDGEOFFSET,L_SET);
				/* write new header */
    if (write (LOCAL->fd,LOCAL->buf + NTKLUDGEOFFSET,
	       HDRSIZE - NTKLUDGEOFFSET) > 0) break;
    mm_notify (stream,strerror (errno),WARN);
    mm_diskerror (stream,errno,T);
  }
}

/* MBX update status string
 * Accepts: MAIL stream
 *	    message number
 *	    flags
 */

void mbx_update_status (MAILSTREAM *stream,unsigned long msgno,long flags)
{
  struct stat sbuf;
  MESSAGECACHE *elt = mail_elt (stream,msgno);
				/* readonly */
  if (stream->rdonly || !elt->valid) mbx_read_flags (stream,elt);
  else {			/* readwrite */
    fstat (LOCAL->fd,&sbuf);	/* get status */
				/* make sure file size is good */
    if (sbuf.st_size < LOCAL->filesize) {
      sprintf (LOCAL->buf,"Mailbox shrank from %lu to %lu in flag update!",
	       (unsigned long) LOCAL->filesize,(unsigned long) sbuf.st_size);
      fatal (LOCAL->buf);
    }
				/* set the seek pointer */
    lseek (LOCAL->fd,(off_t) elt->private.special.offset +
	   elt->private.special.text.size - 24,L_SET);
				/* read the new flags */
    if (read (LOCAL->fd,LOCAL->buf,14) < 0) {
      sprintf (LOCAL->buf,"Unable to read old status: %s",strerror (errno));
      fatal (LOCAL->buf);
    }
    if ((LOCAL->buf[0] != ';') || (LOCAL->buf[13] != '-')) {
      LOCAL->buf[14] = '\0';	/* tie off buffer for error message */
      sprintf (LOCAL->buf+50,"Invalid flags for message %lu (%lu %lu): %s",
	       elt->msgno,elt->private.special.offset,
	       elt->private.special.text.size,(char *) LOCAL->buf);
      fatal (LOCAL->buf+50);
    }
				/* print new flag string */
    sprintf (LOCAL->buf,"%08lx%04x-%08lx",elt->user_flags,(unsigned)
	     (((elt->deleted && flags) ?
	       fEXPUNGED : (strtoul (LOCAL->buf+9,NIL,16)) & fEXPUNGED) +
	      (fSEEN * elt->seen) + (fDELETED * elt->deleted) +
	      (fFLAGGED * elt->flagged) + (fANSWERED * elt->answered) +
	      (fDRAFT * elt->draft) + fOLD),elt->private.uid);
    while (T) {			/* get to that place in the file */
      lseek (LOCAL->fd,(off_t) elt->private.special.offset +
	     elt->private.special.text.size - 23,L_SET);
				/* write new flags and UID */
      if (write (LOCAL->fd,LOCAL->buf,21) > 0) break;
      mm_notify (stream,strerror (errno),WARN);
      mm_diskerror (stream,errno,T);
    }
  }
}

/* MBX locate header for a message
 * Accepts: MAIL stream
 *	    message number
 *	    pointer to returned header size
 *	    pointer to possible returned header
 * Returns: position of header in file
 */

#define HDRBUFLEN 16384		/* good enough for most headers */
#define SLOP 4			/* CR LF CR LF */

unsigned long mbx_hdrpos (MAILSTREAM *stream,unsigned long msgno,
			  unsigned long *size,char **hdr)
{
  unsigned long siz,done;
  long i;
  unsigned char *s,*t,*te;
  MESSAGECACHE *elt = mail_elt (stream,msgno);
  unsigned long ret = elt->private.special.offset +
    elt->private.special.text.size;
  if (hdr) *hdr = NIL;		/* assume no header returned */
				/* is header size known? */ 
  if (*size = elt->private.msg.header.text.size) return ret;
				/* paranoia check */
  if (LOCAL->buflen < (HDRBUFLEN + SLOP))
    fatal ("LOCAL->buf smaller than HDRBUFLEN");
  lseek (LOCAL->fd,ret,L_SET);	/* get to header position */
				/* read HDRBUFLEN chunks with 4 byte slop */
  for (done = siz = 0, s = LOCAL->buf;
       (i = min ((long) (elt->rfc822_size - done),(long) HDRBUFLEN)) &&
       (read (LOCAL->fd,s,i) == i);
       done += i, siz += (t - LOCAL->buf) - SLOP, s = LOCAL->buf + SLOP) {
    te = (t = s + i) - 12;	/* calculate end of fast scan */
				/* fast scan for CR */
    for (s = LOCAL->buf; s < te;)
      if (((*s++ == '\015') || (*s++ == '\015') || (*s++ == '\015') ||
	   (*s++ == '\015') || (*s++ == '\015') || (*s++ == '\015') ||
	   (*s++ == '\015') || (*s++ == '\015') || (*s++ == '\015') ||
	   (*s++ == '\015') || (*s++ == '\015') || (*s++ == '\015')) &&
	  (*s == '\012') && (*++s == '\015') && (*++s == '\012')) {
	*size = elt->private.msg.header.text.size = siz + (++s - LOCAL->buf);
	if (hdr) *hdr = LOCAL->buf;
	return ret;
      }
    for (te = t - 3; (s < te);)	/* final character-at-a-time scan */
      if ((*s++ == '\015') && (*s == '\012') && (*++s == '\015') &&
	  (*++s == '\012')) {
	*size = elt->private.msg.header.text.size = siz + (++s - LOCAL->buf);
	if (hdr) *hdr = LOCAL->buf;
	return ret;
      }
    if (i <= SLOP) break;	/* end of data */
				/* slide over last 4 bytes */
    memmove (LOCAL->buf,t - SLOP,SLOP);
    hdr = NIL;			/* can't return header this way */
  }
				/* not found: header consumes entire message */
  elt->private.msg.header.text.size = *size = elt->rfc822_size;
  if (hdr) *hdr = LOCAL->buf;	/* possibly return header too */
  return ret;
}

/* MBX mail rewrite mailbox
 * Accepts: MAIL stream
 *	    pointer to return reclaimed size
 *	    flags (0 = no expunge, 1 = expunge deleted, -1 = expunge sequence)
 * Returns: number of expunged messages
 */

unsigned long mbx_rewrite (MAILSTREAM *stream,unsigned long *reclaimed,
			   long flags)
{
  struct utimbuf times;
  struct stat sbuf;
  off_t pos,ppos;
  int ld;
  unsigned long i,j,k,m,delta;
  unsigned long n = *reclaimed = 0;
  unsigned long recent = 0;
  char lock[MAILTMPLEN];
  MESSAGECACHE *elt;
				/* get parse/append permission */
  if ((ld = lockname (lock,stream->mailbox,LOCK_EX)) < 0) {
    mm_log ("Unable to lock expunge mailbox",ERROR);
    return 0;
  }
  fstat (LOCAL->fd,&sbuf);	/* get current write time */
  if (LOCAL->filetime && !LOCAL->flagcheck &&
      (LOCAL->filetime < sbuf.st_mtime)) LOCAL->flagcheck = T;
  if (!mbx_parse (stream)) {	/* make sure see any newly-arrived messages */
    unlockfd (ld,lock);		/* failed?? */
    return 0;
  }
  if (LOCAL->flagcheck) {	/* sweep flags if need flagcheck */
    LOCAL->filetime = sbuf.st_mtime;
    for (i = 1; i <= stream->nmsgs; ++i) mbx_elt (stream,i,NIL);
    LOCAL->flagcheck = NIL;
  }

				/* get exclusive access */
  if (!flock (LOCAL->fd,LOCK_EX|LOCK_NB)) {
    mm_critical (stream);	/* go critical */
    for (i = 1,delta = 0,pos = ppos = HDRSIZE; i <= stream->nmsgs; ) {
				/* note if message not at predicted location */
      if (m = (elt = mbx_elt (stream,i,NIL))->private.special.offset - ppos) {
	ppos = elt->private.special.offset;
	*reclaimed += m;	/* note reclaimed message space */
	delta += m;		/* and as expunge delta  */
      }
				/* number of bytes to smash or preserve */
      ppos += (k = elt->private.special.text.size + elt->rfc822_size);
				/* if need to expunge this message*/
      if (flags && elt->deleted && ((flags > 0) || elt->sequence)) {
	delta += k;		/* number of bytes to delete */
	mail_expunged(stream,i);/* notify upper levels */
	n++;			/* count up one more expunged message */
      }
      else {			/* preserved message */
	i++;			/* count this message */
	if (elt->recent) ++recent;
	if (delta) {		/* moved, note first byte to preserve */
	  j = elt->private.special.offset;
	  do {			/* read from source position */
	    m = min (k,LOCAL->buflen);
	    lseek (LOCAL->fd,j,L_SET);
	    read (LOCAL->fd,LOCAL->buf,m);
	    pos = j - delta;	/* write to destination position */
	    while (T) {
	      lseek (LOCAL->fd,pos,L_SET);
	      if (write (LOCAL->fd,LOCAL->buf,m) > 0) break;
	      mm_notify (stream,strerror (errno),WARN);
	      mm_diskerror (stream,errno,T);
	    }
	    pos += m;		/* new position */
	    j += m;		/* next chunk, perhaps */
	  } while (k -= m);	/* until done */
				/* note the new address of this text */
	  elt->private.special.offset -= delta;
	}
				/* preserved but no deleted messages yet */
	else pos = elt->private.special.offset + k;
      }
    }
				/* deltaed file size match position? */
    if (m = (LOCAL->filesize -= delta) - pos) {
      *reclaimed += m;		/* probably an fEXPUNGED msg */
      LOCAL->filesize = pos;	/* set correct size */
    }
				/* truncate file after last message */
    ftruncate (LOCAL->fd,LOCAL->filesize);
    fsync (LOCAL->fd);		/* force disk update */
    mm_nocritical (stream);	/* release critical */
    flock (LOCAL->fd,LOCK_SH);	/* allow sharers again */
  }

  else {			/* can't get exclusive */
    flock (LOCAL->fd,LOCK_SH);	/* recover previous shared mailbox lock */
				/* do hide-expunge when shared */
    if (flags) for (i = 1; i <= stream->nmsgs; ) {
      if (elt = mbx_elt (stream,i,T)) {
				/* make the message invisible */
	if (elt->deleted && ((flags > 0) || elt->sequence)) {
	  mbx_update_status (stream,elt->msgno,LONGT);
				/* notify upper levels */
	  mail_expunged (stream,i);
	  n++;			/* count up one more expunged message */
	}
	else {
	  i++;			/* preserved message */
	  if (elt->recent) ++recent;
	}
      }
      else n++;			/* count up one more expunged message */
    }
    fsync (LOCAL->fd);		/* force disk update */
  }
  fstat (LOCAL->fd,&sbuf);	/* get new write time */
  times.modtime = LOCAL->filetime = sbuf.st_mtime;
  times.actime = time (0);	/* reset atime to now */
  utime (stream->mailbox,&times);
  unlockfd (ld,lock);		/* release exclusive parse/append permission */
				/* notify upper level of new mailbox size */
  mail_exists (stream,stream->nmsgs);
  mail_recent (stream,recent);
  return n;			/* return number of expunged messages */
}

/* MBX mail lock for flag updating
 * Accepts: stream
 * Returns: T if successful, NIL if failure
 */

long mbx_flaglock (MAILSTREAM *stream)
{
  struct stat sbuf;
  unsigned long i;
  int ld;
  char lock[MAILTMPLEN];
				/* no-op if readonly or already locked */
  if (!stream->rdonly && LOCAL && (LOCAL->fd >= 0) && (LOCAL->ld < 0)) {
				/* lock now */
    if ((ld = lockname (lock,stream->mailbox,LOCK_EX)) < 0) return NIL;
    if (!LOCAL->flagcheck) {	/* don't do this if flagcheck already needed */
      if (LOCAL->filetime) {	/* know previous time? */
	fstat (LOCAL->fd,&sbuf);/* get current write time */
	if (LOCAL->filetime < sbuf.st_mtime) LOCAL->flagcheck = T;
	LOCAL->filetime = 0;	/* don't do this test for any other messages */
      }
      if (!mbx_parse (stream)) {/* parse mailbox */
	unlockfd (ld,lock);	/* shouldn't happen */
	return NIL;
      }
      if (LOCAL->flagcheck)	/* invalidate cache if flagcheck */
	for (i = 1; i <= stream->nmsgs; ++i) mail_elt (stream,i)->valid = NIL;
    }
    LOCAL->ld = ld;		/* copy to stream for subsequent calls */
    memcpy (LOCAL->lock,lock,MAILTMPLEN);
  }
  return LONGT;
}