summaryrefslogtreecommitdiff
path: root/lib-src/movemail.c
blob: 406dd8775bccc18b62f65f3958ac0093bf06926e (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
/* movemail foo bar -- move file foo to file bar,
   locking file foo the way /bin/mail respects.
   Copyright (C) 1986, 92, 93, 94, 96, 1999 Free Software Foundation, Inc.

This file is part of GNU Emacs.

GNU Emacs 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, or (at your option)
any later version.

GNU Emacs 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 GNU Emacs; see the file COPYING.  If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

/* Important notice: defining MAIL_USE_FLOCK or MAIL_USE_LOCKF *will
   cause loss of mail* if you do it on a system that does not normally
   use flock as its way of interlocking access to inbox files.  The
   setting of MAIL_USE_FLOCK and MAIL_USE_LOCKF *must agree* with the
   system's own conventions.  It is not a choice that is up to you.

   So, if your system uses lock files rather than flock, then the only way
   you can get proper operation is to enable movemail to write lockfiles there.
   This means you must either give that directory access modes
   that permit everyone to write lockfiles in it, or you must make movemail
   a setuid or setgid program.  */

/*
 * Modified January, 1986 by Michael R. Gretzinger (Project Athena)
 *
 * Added POP (Post Office Protocol) service.  When compiled -DMAIL_USE_POP
 * movemail will accept input filename arguments of the form
 * "po:username".  This will cause movemail to open a connection to
 * a pop server running on $MAILHOST (environment variable).  Movemail
 * must be setuid to root in order to work with POP.
 *
 * New module: popmail.c
 * Modified routines:
 *	main - added code within #ifdef MAIL_USE_POP; added setuid (getuid ())
 *		after POP code.
 * New routines in movemail.c:
 *	get_errmsg - return pointer to system error message
 *
 * Modified August, 1993 by Jonathan Kamens (OpenVision Technologies)
 *
 * Move all of the POP code into a separate file, "pop.c".
 * Use strerror instead of get_errmsg.
 *
 */

#define NO_SHORTNAMES   /* Tell config not to load remap.h */
#include <config.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <stdio.h>
#include <errno.h>

#include <getopt.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#include "syswait.h"
#ifdef MAIL_USE_POP
#include "pop.h"
#endif

#ifdef MSDOS
#undef access
#endif /* MSDOS */

#ifndef DIRECTORY_SEP
#define DIRECTORY_SEP '/'
#endif
#ifndef IS_DIRECTORY_SEP
#define IS_DIRECTORY_SEP(_c_) ((_c_) == DIRECTORY_SEP)
#endif

#ifdef WINDOWSNT
#include "ntlib.h"
#undef access
#undef unlink
#define fork() 0
#define wait(var) (*(var) = 0)
/* Unfortunately, Samba doesn't seem to properly lock Unix files even
   though the locking call succeeds (and indeed blocks local access from
   other NT programs).  If you have direct file access using an NFS
   client or something other than Samba, the locking call might work
   properly - make sure it does before you enable this!

   [18-Feb-97 andrewi] I now believe my comment above to be incorrect,
   since it was based on a misunderstanding of how locking calls are
   implemented and used on Unix.  */
//#define DISABLE_DIRECT_ACCESS

#include <fcntl.h>
#endif /* WINDOWSNT */

#ifndef F_OK
#define F_OK 0
#define X_OK 1
#define W_OK 2
#define R_OK 4
#endif

#if defined (XENIX) || defined (WINDOWSNT)
#include <sys/locking.h>
#endif

#ifdef MAIL_USE_LOCKF
#define MAIL_USE_SYSTEM_LOCK
#endif

#ifdef MAIL_USE_FLOCK
#define MAIL_USE_SYSTEM_LOCK
#endif

#ifdef MAIL_USE_MMDF
extern int lk_open (), lk_close ();
#endif

#if !defined (MAIL_USE_SYSTEM_LOCK) && !defined (MAIL_USE_MMDF) && \
	defined (HAVE_LIBMAIL) && defined (HAVE_MAILLOCK_H)
#include <maillock.h>
/* We can't use maillock unless we know what directory system mail
   files appear in. */
#ifdef MAILDIR
#define MAIL_USE_MAILLOCK
static char *mail_spool_name ();
#endif
#endif

#ifndef errno
extern int errno;
#endif
char *strerror ();
#ifdef HAVE_INDEX
extern char *index __P ((const char *, int));
#endif
#ifdef HAVE_RINDEX
extern char *rindex __P((const char *, int));
#endif

void fatal ();
void error ();
void pfatal_with_name ();
void pfatal_and_delete ();
char *concat ();
long *xmalloc ();
int popmail ();
int pop_retr ();
int mbx_write ();
int mbx_delimit_begin ();
int mbx_delimit_end ();

/* Nonzero means this is name of a lock file to delete on fatal error.  */
char *delete_lockname;

int
main (argc, argv)
     int argc;
     char **argv;
{
  char *inname, *outname;
  int indesc, outdesc;
  int nread;
  WAITTYPE status;
  int c, preserve_mail = 0;

#ifndef MAIL_USE_SYSTEM_LOCK
  struct stat st;
  long now;
  int tem;
  char *lockname, *p;
  char *tempname;
  int desc;
#endif /* not MAIL_USE_SYSTEM_LOCK */

#ifdef MAIL_USE_MAILLOCK
  char *spool_name;
#endif

#ifdef MAIL_USE_POP
  int pop_reverse_order = 0;
# define ARGSTR "pr"
#else /* ! MAIL_USE_POP */
# define ARGSTR "p"
#endif /* MAIL_USE_POP */

#ifdef WINDOWSNT
  /* Ensure all file i/o is in binary mode. */
  _fmode = _O_BINARY;
#endif

  delete_lockname = 0;

  while ((c = getopt (argc, argv, ARGSTR)) != EOF)
    {
      switch (c) {
#ifdef MAIL_USE_POP
      case 'r':
	pop_reverse_order = 1;
	break;
#endif
      case 'p':
	preserve_mail++;
	break;
      default:
	exit(1);
      }
    }

  if (
#ifdef MAIL_USE_POP
      (argc - optind < 2) || (argc - optind > 3)
#else
      (argc - optind != 2)
#endif
      )
    {
      fprintf (stderr, "Usage: movemail [-p] inbox destfile%s\n",
#ifdef MAIL_USE_POP
	       " [POP-password]"
#else
	       ""
#endif
	       );
      exit (1);
    }

  inname = argv[optind];
  outname = argv[optind+1];

#ifdef MAIL_USE_MMDF
  mmdf_init (argv[0]);
#endif

  if (*outname == 0)
    fatal ("Destination file name is empty", 0);

  /* Check access to output file.  */
  if (access (outname, F_OK) == 0 && access (outname, W_OK) != 0)
    pfatal_with_name (outname);

  /* Also check that outname's directory is writable to the real uid.  */
  {
    char *buf = (char *) xmalloc (strlen (outname) + 1);
    char *p;
    strcpy (buf, outname);
    p = buf + strlen (buf);
    while (p > buf && !IS_DIRECTORY_SEP (p[-1]))
      *--p = 0;
    if (p == buf)
      *p++ = '.';
    if (access (buf, W_OK) != 0)
      pfatal_with_name (buf);
    free (buf);
  }

#ifdef MAIL_USE_POP
  if (!strncmp (inname, "po:", 3))
    {
      int status;

      status = popmail (inname + 3, outname, preserve_mail,
			(argc - optind == 3) ? argv[optind+2] : NULL,
			pop_reverse_order);
      exit (status);
    }

  setuid (getuid ());
#endif /* MAIL_USE_POP */

#ifndef DISABLE_DIRECT_ACCESS

  /* Check access to input file.  */
  if (access (inname, R_OK | W_OK) != 0)
    pfatal_with_name (inname);

#ifndef MAIL_USE_MMDF
#ifndef MAIL_USE_SYSTEM_LOCK
#ifdef MAIL_USE_MAILLOCK
  spool_name = mail_spool_name (inname);
  if (! spool_name)
#endif
    {
      /* Use a lock file named after our first argument with .lock appended:
	 If it exists, the mail file is locked.  */
      /* Note: this locking mechanism is *required* by the mailer
	 (on systems which use it) to prevent loss of mail.

	 On systems that use a lock file, extracting the mail without locking
	 WILL occasionally cause loss of mail due to timing errors!

	 So, if creation of the lock file fails
	 due to access permission on the mail spool directory,
	 you simply MUST change the permission
	 and/or make movemail a setgid program
	 so it can create lock files properly.

	 You might also wish to verify that your system is one
	 which uses lock files for this purpose.  Some systems use other methods.

	 If your system uses the `flock' system call for mail locking,
	 define MAIL_USE_SYSTEM_LOCK in config.h or the s-*.h file
	 and recompile movemail.  If the s- file for your system
	 should define MAIL_USE_SYSTEM_LOCK but does not, send a bug report
	 to bug-gnu-emacs@prep.ai.mit.edu so we can fix it.  */

      lockname = concat (inname, ".lock", "");
      tempname = (char *) xmalloc (strlen (inname) + strlen ("EXXXXXX") + 1);
      strcpy (tempname, inname);
      p = tempname + strlen (tempname);
      while (p != tempname && !IS_DIRECTORY_SEP (p[-1]))
	p--;
      *p = 0;
      strcpy (p, "EXXXXXX");
      mktemp (tempname);
      unlink (tempname);

      while (1)
	{
	  /* Create the lock file, but not under the lock file name.  */
	  /* Give up if cannot do that.  */
	  desc = open (tempname, O_WRONLY | O_CREAT | O_EXCL, 0666);
	  if (desc < 0)
	    {
	      char *message = (char *) xmalloc (strlen (tempname) + 50);
	      sprintf (message, "creating %s, which would become the lock file",
		       tempname);
	      pfatal_with_name (message);
	    }
	  close (desc);

	  tem = link (tempname, lockname);
	  unlink (tempname);
	  if (tem >= 0)
	    break;
	  sleep (1);

	  /* If lock file is five minutes old, unlock it.
	     Five minutes should be good enough to cope with crashes
	     and wedgitude, and long enough to avoid being fooled
	     by time differences between machines.  */
	  if (stat (lockname, &st) >= 0)
	    {
	      now = time (0);
	      if (st.st_ctime < now - 300)
		unlink (lockname);
	    }
	}

      delete_lockname = lockname;
    }
#endif /* not MAIL_USE_SYSTEM_LOCK */
#endif /* not MAIL_USE_MMDF */

  if (fork () == 0)
    {
      int lockcount = 0;
      int status = 0;
#if defined (MAIL_USE_MAILLOCK) && defined (HAVE_TOUCHLOCK)
      long touched_lock, now;
#endif

      setuid (getuid ());

#ifndef MAIL_USE_MMDF
#ifdef MAIL_USE_SYSTEM_LOCK
      indesc = open (inname, O_RDWR);
#else  /* if not MAIL_USE_SYSTEM_LOCK */
      indesc = open (inname, O_RDONLY);
#endif /* not MAIL_USE_SYSTEM_LOCK */
#else  /* MAIL_USE_MMDF */
      indesc = lk_open (inname, O_RDONLY, 0, 0, 10);
#endif /* MAIL_USE_MMDF */

      if (indesc < 0)
	pfatal_with_name (inname);

#if defined (BSD_SYSTEM) || defined (XENIX)
      /* In case movemail is setuid to root, make sure the user can
	 read the output file.  */
      /* This is desirable for all systems
	 but I don't want to assume all have the umask system call */
      umask (umask (0) & 0333);
#endif /* BSD_SYSTEM || XENIX */
      outdesc = open (outname, O_WRONLY | O_CREAT | O_EXCL, 0666);
      if (outdesc < 0)
	pfatal_with_name (outname);

      /* This label exists so we can retry locking
	 after a delay, if it got EAGAIN or EBUSY.  */
    retry_lock:

      /* Try to lock it.  */
#ifdef MAIL_USE_MAILLOCK
      if (spool_name)
	{
	  /* The "0 - " is to make it a negative number if maillock returns
	     non-zero. */
	  status = 0 - maillock (spool_name, 1);
#ifdef HAVE_TOUCHLOCK
	  touched_lock = time (0);
#endif
	  lockcount = 5;
	}
      else
#endif /* MAIL_USE_MAILLOCK */
	{
#ifdef MAIL_USE_SYSTEM_LOCK
#ifdef MAIL_USE_LOCKF
	  status = lockf (indesc, F_LOCK, 0);
#else /* not MAIL_USE_LOCKF */
#ifdef XENIX
	  status = locking (indesc, LK_RLCK, 0L);
#else
#ifdef WINDOWSNT
	  status = locking (indesc, LK_RLCK, -1L);
#else
	  status = flock (indesc, LOCK_EX);
#endif
#endif
#endif /* not MAIL_USE_LOCKF */
#endif /* MAIL_USE_SYSTEM_LOCK */
	}

      /* If it fails, retry up to 5 times
	 for certain failure codes.  */
      if (status < 0)
	{
	  if (++lockcount <= 5)
	    {
#ifdef EAGAIN
	      if (errno == EAGAIN)
		{
		  sleep (1);
		  goto retry_lock;
		}
#endif
#ifdef EBUSY
	      if (errno == EBUSY)
		{
		  sleep (1);
		  goto retry_lock;
		}
#endif
	    }

	  pfatal_with_name (inname);
	}

      {
	char buf[1024];

	while (1)
	  {
	    nread = read (indesc, buf, sizeof buf);
	    if (nread != write (outdesc, buf, nread))
	      {
		int saved_errno = errno;
		unlink (outname);
		errno = saved_errno;
		pfatal_with_name (outname);
	      }
	    if (nread < sizeof buf)
	      break;
#if defined (MAIL_USE_MAILLOCK) && defined (HAVE_TOUCHLOCK)
	    if (spool_name)
	      {
		now = time (0);
		if (now - touched_lock > 60)
		  {
		    touchlock ();
		    touched_lock = now;
		  }
	      }
#endif /* MAIL_USE_MAILLOCK */
	  }
      }

#ifdef BSD_SYSTEM
      if (fsync (outdesc) < 0)
	pfatal_and_delete (outname);
#endif

      /* Check to make sure no errors before we zap the inbox.  */
      if (close (outdesc) != 0)
	pfatal_and_delete (outname);

#ifdef MAIL_USE_SYSTEM_LOCK
      if (! preserve_mail)
	{
#if defined (STRIDE) || defined (XENIX)
	  /* Stride, xenix have file locking, but no ftruncate.
	     This mess will do. */
	  close (open (inname, O_CREAT | O_TRUNC | O_RDWR, 0666));
#else
	  ftruncate (indesc, 0L);
#endif /* STRIDE or XENIX */
	}
#endif /* MAIL_USE_SYSTEM_LOCK */

#ifdef MAIL_USE_MMDF
      lk_close (indesc, 0, 0, 0);
#else
      close (indesc);
#endif

#ifndef MAIL_USE_SYSTEM_LOCK
      if (! preserve_mail)
	{
	  /* Delete the input file; if we can't, at least get rid of its
	     contents.  */
#ifdef MAIL_UNLINK_SPOOL
	  /* This is generally bad to do, because it destroys the permissions
	     that were set on the file.  Better to just empty the file.  */
	  if (unlink (inname) < 0 && errno != ENOENT)
#endif /* MAIL_UNLINK_SPOOL */
	    creat (inname, 0600);
	}
#endif /* not MAIL_USE_SYSTEM_LOCK */

#ifdef MAIL_USE_MAILLOCK
      /* This has to occur in the child, i.e., in the process that
         acquired the lock! */
      if (spool_name)
	mailunlock ();
#endif
      exit (0);
    }

  wait (&status);
  if (!WIFEXITED (status))
    exit (1);
  else if (WRETCODE (status) != 0)
    exit (WRETCODE (status));

#if !defined (MAIL_USE_MMDF) && !defined (MAIL_USE_SYSTEM_LOCK)
#ifdef MAIL_USE_MAILLOCK
  if (! spool_name)
#endif /* MAIL_USE_MAILLOCK */
    unlink (lockname);
#endif /* not MAIL_USE_MMDF and not MAIL_USE_SYSTEM_LOCK */

#endif /* ! DISABLE_DIRECT_ACCESS */

  return 0;
}

#ifdef MAIL_USE_MAILLOCK
/* This function uses stat to confirm that the mail directory is
   identical to the directory of the input file, rather than just
   string-comparing the two paths, because one or both of them might
   be symbolic links pointing to some other directory. */
static char *
mail_spool_name (inname)
     char *inname;
{
  struct stat stat1, stat2;
  char *indir, *fname;
  int status;

  if (! (fname = rindex (inname, '/')))
    return NULL;

  fname++;

  if (stat (MAILDIR, &stat1) < 0)
    return NULL;

  indir = (char *) xmalloc (fname - inname + 1);
  strncpy (indir, inname, fname - inname);
  indir[fname-inname] = '\0';


  status = stat (indir, &stat2);

  free (indir);

  if (status < 0)
    return NULL;

  if (stat1.st_dev == stat2.st_dev
      && stat1.st_ino == stat2.st_ino)
    return fname;

  return NULL;
}
#endif /* MAIL_USE_MAILLOCK */

/* Print error message and exit.  */

void
fatal (s1, s2)
     char *s1, *s2;
{
  if (delete_lockname)
    unlink (delete_lockname);
  error (s1, s2, 0);
  exit (1);
}

/* Print error message.  `s1' is printf control string, `s2' and `s3'
   are args for it or null. */

void
error (s1, s2, s3)
     char *s1, *s2, *s3;
{
  fprintf (stderr, "movemail: ");
  if (s3)
    fprintf (stderr, s1, s2, s3);
  else if (s2)
    fprintf (stderr, s1, s2);
  else
    fprintf (stderr, s1);
  fprintf (stderr, "\n");
}

void
pfatal_with_name (name)
     char *name;
{
  char *s = concat ("", strerror (errno), " for %s");
  fatal (s, name);
}

void
pfatal_and_delete (name)
     char *name;
{
  char *s = concat ("", strerror (errno), " for %s");
  unlink (name);
  fatal (s, name);
}

/* Return a newly-allocated string whose contents concatenate those of s1, s2, s3.  */

char *
concat (s1, s2, s3)
     char *s1, *s2, *s3;
{
  int len1 = strlen (s1), len2 = strlen (s2), len3 = strlen (s3);
  char *result = (char *) xmalloc (len1 + len2 + len3 + 1);

  strcpy (result, s1);
  strcpy (result + len1, s2);
  strcpy (result + len1 + len2, s3);
  *(result + len1 + len2 + len3) = 0;

  return result;
}

/* Like malloc but get fatal error if memory is exhausted.  */

long *
xmalloc (size)
     unsigned size;
{
  long *result = (long *) malloc (size);
  if (!result)
    fatal ("virtual memory exhausted", 0);
  return result;
}

/* This is the guts of the interface to the Post Office Protocol.  */

#ifdef MAIL_USE_POP

#ifndef WINDOWSNT
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#else
#undef _WINSOCKAPI_
#include <winsock.h>
#endif
#include <pwd.h>

#define NOTOK (-1)
#define OK 0
#define DONE 1

char *progname;
FILE *sfi;
FILE *sfo;
char ibuffer[BUFSIZ];
char obuffer[BUFSIZ];
char Errmsg[200];		/* POP errors, at least, can exceed
				   the original length of 80.  */

/*
 * The full legal syntax for a POP mailbox specification for movemail
 * is "po:username:hostname".  The ":hostname" is optional; if it is
 * omitted, the MAILHOST environment variable will be consulted.  Note
 * that by the time popmail() is called the "po:" has been stripped
 * off of the front of the mailbox name.
 *
 * If the mailbox is in the form "po:username:hostname", then it is
 * modified by this function -- the second colon is replaced by a
 * null.
 */

int
popmail (mailbox, outfile, preserve, password, reverse_order)
     char *mailbox;
     char *outfile;
     int preserve;
     char *password;
     int reverse_order;
{
  int nmsgs, nbytes;
  register int i;
  int mbfi;
  FILE *mbf;
  char *getenv ();
  popserver server;
  int start, end, increment;
  char *user, *hostname;

  user = mailbox;
  if ((hostname = index(mailbox, ':')))
    *hostname++ = '\0';

  server = pop_open (hostname, user, password, POP_NO_GETPASS);
  if (! server)
    {
      error ("Error connecting to POP server: %s", pop_error, 0);
      return (1);
    }

  if (pop_stat (server, &nmsgs, &nbytes))
    {
      error ("Error getting message count from POP server: %s", pop_error, 0);
      return (1);
    }

  if (!nmsgs)
    {
      pop_close (server);
      return (0);
    }

  mbfi = open (outfile, O_WRONLY | O_CREAT | O_EXCL, 0666);
  if (mbfi < 0)
    {
      pop_close (server);
      error ("Error in open: %s, %s", strerror (errno), outfile);
      return (1);
    }
  fchown (mbfi, getuid (), -1);

  if ((mbf = fdopen (mbfi, "wb")) == NULL)
    {
      pop_close (server);
      error ("Error in fdopen: %s", strerror (errno), 0);
      close (mbfi);
      unlink (outfile);
      return (1);
    }

  if (reverse_order)
    {
      start = nmsgs;
      end = 1;
      increment = -1;
    }
  else
    {
      start = 1;
      end = nmsgs;
      increment = 1;
    }

  for (i = start; i * increment <= end * increment; i += increment)
    {
      mbx_delimit_begin (mbf);
      if (pop_retr (server, i, mbf) != OK)
	{
	  error (Errmsg, 0, 0);
	  close (mbfi);
	  return (1);
	}
      mbx_delimit_end (mbf);
      fflush (mbf);
      if (ferror (mbf))
	{
	  error ("Error in fflush: %s", strerror (errno), 0);
	  pop_close (server);
	  close (mbfi);
	  return (1);
	}
    }

  /* On AFS, a call to write only modifies the file in the local
   *     workstation's AFS cache.  The changes are not written to the server
   *      until a call to fsync or close is made.  Users with AFS home
   *      directories have lost mail when over quota because these checks were
   *      not made in previous versions of movemail. */

#ifdef BSD_SYSTEM
  if (fsync (mbfi) < 0)
    {
      error ("Error in fsync: %s", strerror (errno), 0);
      return (1);
    }
#endif

  if (close (mbfi) == -1)
    {
      error ("Error in close: %s", strerror (errno), 0);
      return (1);
    }

  if (! preserve)
    for (i = 1; i <= nmsgs; i++)
      {
	if (pop_delete (server, i))
	  {
	    error ("Error from POP server: %s", pop_error, 0);
	    pop_close (server);
	    return (1);
	  }
      }

  if (pop_quit (server))
    {
      error ("Error from POP server: %s", pop_error, 0);
      return (1);
    }

  return (0);
}

int
pop_retr (server, msgno, arg)
     popserver server;
     int msgno;
     FILE *arg;
{
  extern char *strerror ();
  char *line;
  int ret;

  if (pop_retrieve_first (server, msgno, &line))
    {
      char *error = concat ("Error from POP server: ", pop_error, "");
      strncpy (Errmsg, error, sizeof (Errmsg));
      Errmsg[sizeof (Errmsg)-1] = '\0';
      free(error);
      return (NOTOK);
    }

  while ((ret = pop_retrieve_next (server, &line)) >= 0)
    {
      if (! line)
	break;

      if (mbx_write (line, ret, arg) != OK)
	{
	  strcpy (Errmsg, strerror (errno));
	  pop_close (server);
	  return (NOTOK);
	}
    }

  if (ret)
    {
      char *error = concat ("Error from POP server: ", pop_error, "");
      strncpy (Errmsg, error, sizeof (Errmsg));
      Errmsg[sizeof (Errmsg)-1] = '\0';
      free(error);
      return (NOTOK);
    }

  return (OK);
}

/* Do this as a macro instead of using strcmp to save on execution time. */
#define IS_FROM_LINE(a) ((a[0] == 'F') \
			 && (a[1] == 'r') \
			 && (a[2] == 'o') \
			 && (a[3] == 'm') \
			 && (a[4] == ' '))

int
mbx_write (line, len, mbf)
     char *line;
     int len;
     FILE *mbf;
{
#ifdef MOVEMAIL_QUOTE_POP_FROM_LINES
  if (IS_FROM_LINE (line))
    {
      if (fputc ('>', mbf) == EOF)
	return (NOTOK);
    }
#endif
  if (line[0] == '\037')
    {
      if (fputs ("^_", mbf) == EOF)
	return (NOTOK);
      line++;
      len--;
    }
  if (fwrite (line, 1, len, mbf) != len)
    return (NOTOK);
  if (fputc (0x0a, mbf) == EOF)
    return (NOTOK);
  return (OK);
}

int
mbx_delimit_begin (mbf)
     FILE *mbf;
{
  if (fputs ("\f\n0, unseen,,\n", mbf) == EOF)
    return (NOTOK);
  return (OK);
}

int
mbx_delimit_end (mbf)
     FILE *mbf;
{
  if (putc ('\037', mbf) == EOF)
    return (NOTOK);
  return (OK);
}

#endif /* MAIL_USE_POP */

#ifndef HAVE_STRERROR
char *
strerror (errnum)
     int errnum;
{
  extern char *sys_errlist[];
  extern int sys_nerr;

  if (errnum >= 0 && errnum < sys_nerr)
    return sys_errlist[errnum];
  return (char *) "Unknown error";
}

#endif /* ! HAVE_STRERROR */