summaryrefslogtreecommitdiff
path: root/examples/mta.c
blob: f52b7df8fd7fa542490febc9bfab440b253a8b1d (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
/* GNU Mailutils -- a suite of utilities for electronic mail
   Copyright (C) 1999, 2000, 2001 Free Software Foundation, Inc.

   GNU Mailutils 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 Mailutils 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 Mailutils; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

/* This is a "fake" mta designed for testing purposes. It imitates
   sendmail sending and daemon modes. It does not actually send anything,
   instead it just outputs the transcript of what would have been done.

   Invocation:
   
   1. mta [-t][-oi][-f from-person] [recipients]

   Reads the message from the standard input and delivers it to each of the
   recipients.

   2. mta -bd [-p port]

   Operates as daemon. If port is given, mta will listen on that port.
   Otherwise, it will use the first free port in the range 1024-65535.
   In this case, mta prints the port number on the stdout, prior to
   starting operation. Notice, that in this mode mta does not disconnect
   itself from the controlling terminal, it always stays on the foreground.

   Environment variables:

   MTA_DOMAIN   Sets the default domain name for email addresses. Default
                is "localhost".
   MTA_DIAG     Sets the name of the output diagnostic file. By default,
                the diagnostics goes to stderr.
   MTA_APPEND   When set to any non-empty value, directs mta to append
                to the diagnostics file, not to overwrite it. 

*/

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <stdlib.h>
#include <unistd.h>
#ifdef HAVE_GETOPT_H
# include <getopt.h>
#endif
#include <string.h>
#include <pwd.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <mu_asprintf.h>
#include <mailutils/argcv.h>
#include <mailutils/mailutils.h>

FILE *diag = NULL;       /* diagnostic output */
int smtp_mode;           /* Operate in smtp mode */
int port = 0;            /* Port number (for smtp mode) */
char *from_person = NULL; /* Set the name of the `from' person */
int read_recipients = 0; /* Read the message for recipients */
int dot = 1;             /* Message is terminated by a lone dot on a line */

header_t header;
address_t recipients = NULL;
char *progname;

int mta_stdin __P((int argc, char **argv));
int mta_smtp __P((int argc, char **argv));
void register_handlers __P((void));

int
main (int argc, char **argv)
{
  int c, status;
  char *domain;

  progname = strrchr (argv[0], '/');
  if (!progname)
    progname = argv[0];
  
  while ((c = getopt (argc, argv, "b:f:p:to:")) != EOF)
    {
      switch (c)
	{
	case 'b':
	  switch (optarg[0])
	    {
	    case 'd':
	      smtp_mode = 1;
	      break;

	    default:
	      /*FIXME*/;
	    }
	  break;
	  
	case 'f':
	  from_person = optarg;
	  break;
	  
	case 'p':
	  port = strtoul (optarg, NULL, 0);
	  break;
	  
	case 't':
	  read_recipients = 1;
	  break;

	case 'o':
	  switch (optarg[0])
	    {
	    case 'i':
	      dot = 0;
	      break;

	    default:
	      /* FIXME */ ;
	    }
	  break;

	default:
	  exit (1);
	}
    }

  if (!diag)
    {
      char *name = getenv ("MTA_DIAG");
      if (name)
	{
	  char *mode = getenv ("MTA_APPEND") ? "a" : "w";
	  diag = fopen (name, mode);
	  if (!diag)
	    {
	      mu_error ("%s: can't open diagnostic output: %s",
			progname, name);
	      return 1;
	    }
	}
      else
	diag = stdout;
    }
  
  register_handlers ();

  domain = getenv ("MTA_DOMAIN");
  mu_set_user_email_domain (domain ? domain : "localhost");
  
  if ((status = header_create (&header, NULL, 0, NULL)) != 0)
    {
      mu_error ("%s: can't create header: %s",
		progname, mu_errstring (status));
      return 1;
    }

  argc -= optind;
  argv += optind;
  if (smtp_mode)
    status = mta_smtp (argc, argv);
  else
    status = mta_stdin (argc, argv);
  fclose (diag);
  return status;
}

char *
from_address ()
{
  if (!from_person)
    {
      struct passwd *pwd = getpwuid (getuid ());
      if (pwd)
	return mu_get_user_email (pwd->pw_name);
    }
  return strdup (from_person);
}
     
void
make_tmp (FILE *input, const char *from, char **tempfile)
{
  time_t t;
  int fd = mu_tempfile (NULL, tempfile);
  FILE *fp;
  char *buf = NULL;
  size_t n = 0;
  int line;
  
  if (fd == -1 || (fp = fdopen (fd, "w+")) == NULL)
    {
      mu_error ("%s: unable to open temporary file", progname);
      exit (1);
    }

  line = 0;
  while (getline (&buf, &n, input) > 0)
    {
      int len = strlen (buf);
      if (len >= 2 && buf[len - 2] == '\r')
	{
	  buf[len - 2] = '\n';
	  buf[len - 1] = 0;
	}
	  
      //fprintf (diag, "%s", buf); //FM
      line++;
      if (line == 1)
	{
	  if (memcmp (buf, "From ", 5))
	    {
	      char *from = from_address ();
	      if (from)
		{
		  time (&t);
		  fprintf (fp, "From %s %s", from, ctime (&t));
		  free (from);
		}
	      else
		{
		  mu_error ("%s: can't determine sender address", progname);
		  exit (1);
		}
	    }
	}
      else if (!memcmp (buf, "From ", 5))
	fputc ('>', fp);

      if (dot && buf[0] == '.' &&
	       ((buf[1] == '\r' && buf[2] == '\n') || (buf[1] == '\n')))
	break;
      
      if (fputs (buf, fp) == EOF)
	{
	  mu_error ("%s: temporary file write error", progname);
	  fclose (fp);
	  exit (1);
	}
    }
  
  if (buf && strchr (buf, '\n') == NULL)
    putc ('\n', fp);

  putc ('\n', fp);
  free (buf);

  fclose (fp);
}

void
register_handlers ()
{
  list_t bookie;

  registrar_get_list (&bookie);
  list_append (bookie, path_record);
  list_append (bookie, sendmail_record);
  list_append (bookie, smtp_record);
}

int
add_recipient (const char *name)
{
  address_t addr;
  int status;
    
  status = address_create (&addr, name);
  if (status == 0)
    status = address_union (&recipients, addr);
  address_destroy (&addr);
  return status;
}

int
mta_send (message_t msg)
{
  int c;
  size_t n;
  char buffer[512];    
  stream_t stream = NULL;
  size_t off = 0, line;
  char *value;

  value = from_address ();
  if (value)
    {
      fprintf (diag, "ENVELOPE FROM: %s\n", value);
      free (value);
    }
  
  c = address_to_string (recipients, NULL, 0, &n);
  if (c)
    {
      mu_error ("%s: address_to_string failure: %s",
		progname, mu_errstring (c));
      return 1;
    }
  value = malloc (n + 1);
  if (!value)
    {
      mu_error ("%s: not enough memory", progname);
      return 1;
    }

  address_to_string (recipients, value, n + 1, &n);
  fprintf (diag, "ENVELOPE TO: %s\n", value);
  free (value);

  message_get_stream (msg, &stream);
  line = 0;
  fprintf (diag, "%4lu: ", (unsigned long) line);
  while (stream_read (stream, buffer, sizeof buffer - 1, off, &n) == 0
	 && n != 0)
    {
      size_t i;

      for (i = 0; i < n; i++)
	{
	  fputc (buffer[i], diag);
	  if (buffer[i] == '\n')
	    {
	      line++;
	      fprintf (diag, "%4lu: ", (unsigned long) line);
	    }
	}
      off += n;
    }
  fprintf (diag, "\nEND OF MESSAGE\n");
  fflush (diag);
  return 0;
}

#define SENDER_WARNING "set sender using -f flag"

int
message_finalize (message_t msg, int warn)
{
  header_t header = NULL;
  int have_to;
  char *value = NULL;
  
  message_get_header (msg, &header);

  if (warn && from_person)
    {
      struct passwd *pwd = getpwuid (getuid ());
      char *warn = malloc (strlen (pwd->pw_name) + 1 +
			   sizeof (SENDER_WARNING));
      if (warn == NULL)
	{
	  mu_error ("%s: not enough memory", progname);
	  return 1;
	}
      sprintf (warn, "%s %s", pwd->pw_name, SENDER_WARNING);
      header_set_value (header, "X-Authentication-Warning", warn, 0);
      free (warn);
    }
  
  have_to = header_aget_value (header, MU_HEADER_TO, &value) == 0;
  
  if (read_recipients)
    {
      if (value)
	{
	  if (add_recipient (value))
	    {
	      mu_error ("%s: bad address %s", progname, value);
	      return 1;
	    }
	  free (value);
	}
	  
      if (header_aget_value (header, MU_HEADER_CC, &value) == 0)
	{
	  if (add_recipient (value))
	    {
	      mu_error ("%s: bad address %s", progname, value);
	      return 1;
	    }
	  free (value);
	}  
	  
      if (header_aget_value (header, MU_HEADER_BCC, &value) == 0)
	{
	  if (add_recipient (value))
	    {
	      mu_error ("%s: bad address %s: %s", progname, value);
	      return 1;
	    }
	  free (value);
	  header_set_value (header, MU_HEADER_BCC, NULL, 1);
	}  
    }

  if (!have_to)
    {
      size_t n;
      int c;
      
      c = address_to_string (recipients, NULL, 0, &n);
      if (c)
	{
	  mu_error ("%s: address_to_string failure: %s",
		    progname, mu_errstring (c));
	  return 1;
	}
      value = malloc (n + 1);
      if (!value)
	{
	  mu_error ("%s: not enough memory", progname);
	  return 1;
	}

      address_to_string (recipients, value, n + 1, &n);
      header_set_value (header, MU_HEADER_TO, value, 1);
      free (value);
    }
  return 0;
}

int
mta_stdin (int argc, char **argv)
{
  int c;
  char *tempfile;
  mailbox_t mbox;
  message_t msg = NULL;
  
  for (c = 0; c < argc; c++)
    {
      if (add_recipient (argv[c]))
	{
	  mu_error ("%s: bad address %s", progname, argv[c]);
	  return 1;
	}
    }

  make_tmp (stdin, from_person, &tempfile);
  if ((c = mailbox_create_default (&mbox, tempfile)) != 0)
    {
      mu_error ("%s: can't create mailbox %s: %s",
		progname, tempfile, mu_errstring (c));
      unlink (tempfile);
      return 1;
    }

  if ((c = mailbox_open (mbox, MU_STREAM_RDWR)) != 0)
    {
      mu_error ("%s: can't open mailbox %s: %s",
		progname, tempfile, mu_errstring (c));
      unlink (tempfile);
      return 1;
    }

  mailbox_get_message (mbox, 1, &msg);
  if (message_finalize (msg, 1))
    return 1;

  if (!recipients)
    {
      mu_error ("%s: Recipient names must be specified", progname);
      return 1;
    }

  mta_send (msg);
  
  unlink (tempfile);
  free (tempfile);
  return 0;
}

FILE *in, *out;

void
smtp_reply (int code, char *fmt, ...)
{
  va_list ap;

  va_start (ap, fmt);
  fprintf (out, "%d ", code);
  vfprintf (out, fmt, ap);
  va_end (ap);
  fprintf (out, "\r\n");
}

#define STATE_INIT   0
#define STATE_EHLO   1
#define STATE_MAIL   2
#define STATE_RCPT   3
#define STATE_DATA   4  
#define STATE_QUIT   5 
#define STATE_DOT    6

#define KW_EHLO      0
#define KW_HELO      1
#define KW_MAIL      2
#define KW_RCPT      3
#define KW_DATA      4   
#define KW_HELP      5
#define KW_QUIT      6

int
smtp_kw (const char *name)
{
  static struct kw {
    char *name;
    int code;
  } kw[] = {
    { "ehlo", KW_EHLO },      
    { "helo", KW_HELO },       
    { "mail", KW_MAIL },
    { "rcpt", KW_RCPT },
    { "data", KW_DATA },
    { "help", KW_HELP },
    { "quit", KW_QUIT },
    { NULL },
  };
  int i;

  for (i = 0; kw[i].name != NULL; i++)
    if (strcasecmp (name, kw[i].name) == 0)
      return kw[i].code;
  return -1;
}

void
smtp (int fd)
{
  int state, c;
  char *buf = NULL;
  size_t size = 0;
  mailbox_t mbox;
  message_t msg;
  char *tempfile;
  
  in = fdopen (fd, "r");
  out = fdopen (fd, "w");
  SETVBUF (in, NULL, _IOLBF, 0);
  SETVBUF (out, NULL, _IOLBF, 0);

  smtp_reply (220, "Ready");
  for (state = STATE_INIT; state != STATE_QUIT; )
    {
      int argc;
      char **argv;
      int kw, len;
      
      if (getline (&buf, &size, in) == -1)
	exit (1);
      //fprintf (diag, "%s", buf); //FM
      len = strlen (buf);
      while (len > 0 && (buf[len-1] == '\n' || buf[len-1] == '\r'))
	len --;
      buf[len] = 0;
      
      if (argcv_get (buf, "", NULL, &argc, &argv))
	exit (1);

      kw = smtp_kw (argv[0]);
      if (kw == KW_QUIT)
	{
	  smtp_reply (221, "Done");
	  state = STATE_QUIT;
	  argcv_free (argc, argv);
	  continue;
	}
      
      switch (state)
	{
	case STATE_INIT:
	  switch (kw)
	    {
	    case KW_EHLO:
	    case KW_HELO:
	      if (argc == 2)
		{
		  smtp_reply (250, "pleased to meet you");
		  state = STATE_EHLO;
		}
	      else
		smtp_reply (501, "%s requires domain address", argv[0]);
	      break;

	    default:
	      smtp_reply (503, "Polite people say HELO first");
	      break;
	    }
	  break;
	  
	case STATE_EHLO:
	  switch (kw)
	    {
	    case KW_MAIL:
	      if (argc == 3 && strcasecmp (argv[1], "from:") == 0)
		{
		  from_person = strdup (argv[2]);
		  smtp_reply (250, "Sender OK");
		  state = STATE_MAIL;
		}
	      else
		smtp_reply (501, "Syntax error");
	      break;

	    default:
	      smtp_reply (503, "Need MAIL command");
	    }
	  break;
	  
	case STATE_MAIL:
	  switch (kw)
	    {
	    case KW_RCPT:
	      if (argc == 3 && strcasecmp (argv[1], "to:") == 0)
		{
		  if (add_recipient (argv[2]))
		    smtp_reply (451, "Recipient not accepted");
		  else
		    {
		      smtp_reply (250, "Recipient OK");
		      state = STATE_RCPT;
		    }
		}
	      else
		smtp_reply (501, "Syntax error");
	      break;
	      
	    default:
	      smtp_reply (503, "Need RCPT command");
	    }
	  break;
	  
	case STATE_RCPT:
	  switch (kw)
	    {
	    case KW_RCPT:
	      if (argc == 3 && strcasecmp (argv[1], "to:") == 0)
		{
		  if (add_recipient (argv[2]))
		    smtp_reply (451, "Recipient not accepted");
		  else
		    smtp_reply (250, "Recipient OK");
		}
	      else
		smtp_reply (501, "Syntax error");
	      break;

	    case KW_DATA:
	      smtp_reply (354,
			  "Enter mail, end with \".\" on a line by itself");
	      make_tmp (in, from_person, &tempfile);
	      if ((c = mailbox_create_default (&mbox, tempfile)) != 0)
		{
		  mu_error ("%s: can't create mailbox %s: %s",
			    progname,
			    tempfile, mu_errstring (c));
		  unlink (tempfile);
		  exit (1);
		}

	      if ((c = mailbox_open (mbox, MU_STREAM_RDWR)) != 0)
		{
		  mu_error ("%s: can't open mailbox %s: %s",
			    progname, 
			    tempfile, mu_errstring (c));
		  unlink (tempfile);
		  exit (1);
		}

	      mailbox_get_message (mbox, 1, &msg);
	      if (message_finalize (msg, 0) == 0)
		mta_send (msg);
	      else
		smtp_reply (501, "can't send message"); /*FIXME: code?*/
	      unlink (tempfile);

	      address_destroy (&recipients);
	      from_person = NULL;
	      
	      smtp_reply (250, "Message accepted for delivery");
	      state = STATE_EHLO;
	      break;

	    default:
	      smtp_reply (503, "Invalid command");
	      break;
	    }
	  break;

	}
      argcv_free (argc, argv);
    }
    
  close (fd);
}

int
mta_smtp (int argc, char **argv)
{
  int on = 1;
  struct sockaddr_in address;
  int fd;
  
  fd = socket (PF_INET, SOCK_STREAM, 0);
  if (fd < 0)
    {
      mu_error ("%s: socket: %s", progname, strerror (errno));
      return 1;
    }

  setsockopt (fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof (on));

  memset (&address, 0, sizeof (address));
  address.sin_family = AF_INET;
  address.sin_addr.s_addr = INADDR_ANY;

  if (port)
    {
      address.sin_port = htons (port);
      if (bind (fd, (struct sockaddr *) &address, sizeof (address)) < 0)
	{
	  close (fd);
	  mu_error ("%s: bind: %s", progname, strerror(errno));
	  return 1;
	}
    }
  else
    {
      int status;
      
      port = 1023;
      do
	{
	  if (++port >= 65535)
	    {
	      mu_error ("%s: can't bind socket: all ports in use?",
			progname);
	      return 1;
	    }
	  address.sin_port = htons (port);
	  status = bind (fd, (struct sockaddr *) &address, sizeof (address));
	}
      while (status < 0);
      printf ("%d\n", port);
      fclose (stdout);
    }

  listen (fd, 5);
  while (1)
    {
      fd_set rfds;
      struct sockaddr_in his_addr;
      int sfd, len, status;

      FD_ZERO (&rfds);
      FD_SET (fd, &rfds);
      
      status = select (fd + 1, &rfds, NULL, NULL, NULL);
      if (status == -1)
	{
	  if (errno == EINTR)
	    continue;
	  mu_error ("%s: select: %s", progname, strerror (errno));
	  return 1;
	}

      len = sizeof (his_addr);
      if ((sfd = accept (fd, (struct sockaddr *)&his_addr, &len)) < 0)
	{
	  mu_error ("%s: accept: %s", progname, strerror (errno));
	  return 1;
	}

      smtp (sfd);
      break;
    }
  
  return 0;
}

Return to:

Send suggestions and report system problems to the System administrator.