summaryrefslogtreecommitdiff
path: root/imap4d/imap4d.c
blob: 5ac591c1aa4f5c3d062ff31578ecdfe52b304f61 (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
/* GNU Mailutils -- a suite of utilities for electronic mail
   Copyright (C) 1999, 2001, 2002, 2003, 2004, 
   2005, 2006, 2007 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 3, 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., 51 Franklin Street, Fifth Floor, Boston,
   MA 02110-1301 USA */

#include "imap4d.h"
#ifdef WITH_GSASL
# include <mailutils/gsasl.h>
#endif
#include "mailutils/libargp.h"

mu_mailbox_t mbox;
char *homedir;
int state = STATE_NONAUTH;
int debug_mode = 0;
struct mu_auth_data *auth_data;

struct mu_gocs_daemon default_gocs_daemon = {
  MODE_INTERACTIVE,		/* Start in interactive (inetd) mode */
  20,				/* Default maximum number of children */
  143,				/* Standard IMAP4 port */
  1800,				/* RFC2060: 30 minutes. */
  0,				/* No transcript by default */
  NULL                          /* No PID file by default */
};

int login_disabled;             /* Disable LOGIN command */
int tls_required;               /* Require STARTTLS */
int create_home_dir;            /* Create home directory if it does not
				   exist */
int home_dir_mode = S_IRUSR|S_IWUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH;


/* Number of child processes.  */
size_t children;

const char *program_version = "imap4d (" PACKAGE_STRING ")";
static char doc[] = N_("GNU imap4d -- the IMAP4D daemon");

#define ARG_LOGIN_DISABLED  1
#define ARG_TLS_REQUIRED    2
#define ARG_CREATE_HOME_DIR 3

static struct argp_option options[] = {
  {"other-namespace", 'O', N_("PATHLIST"), OPTION_HIDDEN,
   N_("Set the `other' namespace"), 0},
  {"shared-namespace", 'S', N_("PATHLIST"), OPTION_HIDDEN,
   N_("Set the `shared' namespace"), 0},
  {"login-disabled", ARG_LOGIN_DISABLED, NULL, OPTION_HIDDEN,
   N_("Disable LOGIN command")},
  {"create-home-dir", ARG_CREATE_HOME_DIR, N_("MODE"),
   OPTION_ARG_OPTIONAL|OPTION_HIDDEN,
   N_("Create home directory, if it does not exist")},
#ifdef WITH_TLS
  {"tls-required", ARG_TLS_REQUIRED, NULL, OPTION_HIDDEN,
   N_("Always require STARTTLS before entering authentication phase")},
#endif
  {NULL, 0, NULL, 0, NULL, 0}
};


static error_t imap4d_parse_opt (int key, char *arg,
				 struct argp_state *state);

static struct argp argp = {
  options,
  imap4d_parse_opt,
  NULL,
  doc,
  NULL,
  NULL, NULL
};

static const char *imap4d_capa[] = {
  "daemon",
  "auth",
  "common",
  "mailbox",
  "logging",
  "license",
  NULL
};

static void imap4d_daemon_init (void);
static void imap4d_daemon (unsigned int, unsigned int);
static int imap4d_mainloop (int, FILE *, FILE *);

static error_t
imap4d_parse_opt (int key, char *arg, struct argp_state *state)
{
  switch (key)
    {
    case ARGP_KEY_INIT:
      state->child_inputs[0] = state->input;
      break;

    case 'O':
      set_namespace (NS_OTHER, arg);
      break;

    case 'S':
      set_namespace (NS_SHARED, arg);
      break;

    case ARG_LOGIN_DISABLED:
      login_disabled = 1;
      break;

    case ARG_CREATE_HOME_DIR:
      create_home_dir = 1;
      if (arg)
	{
	  char *p;
	  home_dir_mode = strtoul (arg, &p, 8);
	  if (p || (home_dir_mode & 0777))
	    argp_error (state, _("Invalid mode specification: %s"), arg);
	}
      break;
	
#ifdef WITH_TLS
    case ARG_TLS_REQUIRED:
      tls_required = 1;
      break;
#endif
      
    default:
      return ARGP_ERR_UNKNOWN;
    }
  return 0;
}

static int
cb_other (mu_cfg_locus_t *locus, void *data, char *arg)
{
  set_namespace (NS_OTHER, arg);
  return 0;
}

static int
cb_shared (mu_cfg_locus_t *locus, void *data, char *arg)
{
  set_namespace (NS_SHARED, arg);
  return 0;
}

static int
cb_mode (mu_cfg_locus_t *locus, void *data, char *arg)
{
  char *p;
  home_dir_mode = strtoul (arg, &p, 8);
  if (p || (home_dir_mode & 0777))
    mu_error (_("%s:%d: Invalid mode specification: %s"),
	      locus->file, locus->line, arg);
  return 0;
}

static struct mu_cfg_param imap4d_cfg_param[] = {
  { "other-namespace", mu_cfg_callback, NULL, cb_other },
  { "shared-namespace", mu_cfg_callback, NULL, cb_shared },
  { "login-disabled", mu_cfg_int, &login_disabled },
  { "create-home-dir", mu_cfg_bool, &create_home_dir },
  { "home-dir-mode", mu_cfg_callback, NULL, cb_mode },
  { "tls-required", mu_cfg_int, &tls_required },
  { NULL }
};
    
int
main (int argc, char **argv)
{
  struct group *gr;
  int status = EXIT_SUCCESS;

  /* Native Language Support */
  mu_init_nls ();

  state = STATE_NONAUTH;	/* Starting state in non-auth.  */

  MU_AUTH_REGISTER_ALL_MODULES ();
  imap4d_capability_init ();
  mu_gocs_daemon = default_gocs_daemon;
#ifdef WITH_TLS
  mu_gocs_register ("tls", mu_tls_module_init);
#endif /* WITH_TLS */
#ifdef WITH_GSASL
  mu_gocs_register ("gsasl", mu_gsasl_module_init);
#endif
  mu_argp_init (program_version, NULL);
  if (mu_app_init (&argp, imap4d_capa, imap4d_cfg_param, 
		   argc, argv, 0, NULL, NULL))
    exit (1);

  if (login_disabled)
    imap4d_capability_add (IMAP_CAPA_LOGINDISABLED);
#ifdef WITH_TLS
  if (tls_required)
    imap4d_capability_add (IMAP_CAPA_XTLSREQUIRED);
#endif
  
  auth_gssapi_init ();
  auth_gsasl_init ();
  
#ifdef USE_LIBPAM
  if (!mu_pam_service)
    mu_pam_service = "gnu-imap4d";
#endif

  if (mu_gocs_daemon.mode == MODE_INTERACTIVE && isatty (0))
    {
      /* If input is a tty, switch to debug mode */
      debug_mode = 1;
    }
  else
    {
      /* Normal operation: */
      /* First we want our group to be mail so we can access the spool.  */
      gr = getgrnam ("mail");
      if (gr == NULL)
	{
	  perror (_("Error getting mail group"));
	  exit (1);
	}

      if (setgid (gr->gr_gid) == -1)
	{
	  perror (_("Error setting mail group"));
	  exit (1);
	}
    }

  /* Register the desired formats. */
  mu_register_local_mbox_formats ();
  
  /* Set the signal handlers.  */
  signal (SIGINT, imap4d_signal);
  signal (SIGQUIT, imap4d_signal);
  signal (SIGILL, imap4d_signal);
  signal (SIGBUS, imap4d_signal);
  signal (SIGFPE, imap4d_signal);
  signal (SIGSEGV, imap4d_signal);
  signal (SIGTERM, imap4d_signal);
  signal (SIGSTOP, imap4d_signal);
  signal (SIGPIPE, imap4d_signal);
  /*signal (SIGPIPE, SIG_IGN); */
  signal (SIGABRT, imap4d_signal);

  if (mu_gocs_daemon.mode == MODE_DAEMON)
    imap4d_daemon_init ();
  else
    {
      /* Make sure we are in the root.  */
      chdir ("/");
    }

  /* Set up for syslog.  */
  openlog ("gnu-imap4d", LOG_PID, log_facility);

  /* Redirect any stdout error from the library to syslog, they
     should not go to the client.  */
  mu_error_set_print (mu_syslog_error_printer);

  umask (S_IROTH | S_IWOTH | S_IXOTH);	/* 007 */

  if (mu_gocs_daemon.pidfile)
    {
      mu_daemon_create_pidfile (mu_gocs_daemon.pidfile);
    }

  /* Check TLS environment, i.e. cert and key files */
#ifdef WITH_TLS
  starttls_init ();
#endif /* WITH_TLS */

  /* Actually run the daemon.  */
  if (mu_gocs_daemon.mode == MODE_DAEMON)
    imap4d_daemon (mu_gocs_daemon.maxchildren, mu_gocs_daemon.port);
  /* exit (0) -- no way out of daemon except a signal.  */
  else
    status = imap4d_mainloop (fileno (stdin), stdin, stdout);

  /* Close the syslog connection and exit.  */
  closelog ();

  return status;
}

static int
imap4d_mainloop (int fd, FILE *infile, FILE *outfile)
{
  char *text;

  /* Reset hup to exit.  */
  signal (SIGHUP, imap4d_signal);
  /* Timeout alarm.  */
  signal (SIGALRM, imap4d_signal);

  util_setio (infile, outfile);

  /* log information on the connecting client */
  if (!debug_mode)
    {
      struct sockaddr_in cs;
      int len = sizeof cs;

      syslog (LOG_INFO, _("Incoming connection opened"));
      if (getpeername (fd, (struct sockaddr *) &cs, &len) < 0)
	syslog (LOG_ERR, _("Cannot obtain IP address of client: %s"),
		strerror (errno));
      else
	syslog (LOG_INFO, _("Connect from %s"), inet_ntoa (cs.sin_addr));
      text = "IMAP4rev1";
    }
  else
    {
      syslog (LOG_INFO, _("Started in debugging mode"));
      text = "IMAP4rev1 Debugging mode";
    }

  /* Greetings.  */
  util_out (RESP_OK, text);
  util_flush_output ();

  while (1)
    {
      char *cmd = imap4d_readline ();
      /* check for updates */
      imap4d_sync ();
      util_do_command (cmd);
      imap4d_sync ();
      free (cmd);
      util_flush_output ();
    }

  return EXIT_SUCCESS;
}

/* Sets things up for daemon mode.  */
static void
imap4d_daemon_init (void)
{
  extern int daemon (int, int);

  /* Become a daemon. Take care to close inherited fds and to hold
     first three one, in, out, err   */
  if (daemon (0, 0) < 0)
    {
      perror (_("could not become daemon"));
      exit (1);
    }

  /* SIGCHLD is not ignore but rather use to do some simple load balancing.  */
#ifdef HAVE_SIGACTION
  {
    struct sigaction act;
    act.sa_handler = imap4d_sigchld;
    sigemptyset (&act.sa_mask);
    act.sa_flags = 0;
    sigaction (SIGCHLD, &act, NULL);
  }
#else
  signal (SIGCHLD, imap4d_sigchld);
#endif
}

/* Runs GNU imap4d in standalone daemon mode. This opens and binds to a port
   (default 143) then executes a imap4d_mainloop() upon accepting a connection.
   It starts maxchildren child processes to listen to and accept socket
   connections.  */
static void
imap4d_daemon (unsigned int maxchildren, unsigned int port)
{
  struct sockaddr_in server, client;
  pid_t pid;
  int listenfd, connfd;
  size_t size;

  listenfd = socket (PF_INET, SOCK_STREAM, 0);
  if (listenfd == -1)
    {
      syslog (LOG_ERR, "socket: %s", strerror (errno));
      exit (1);
    }
  size = 1;			/* Use size here to avoid making a new variable.  */
  setsockopt (listenfd, SOL_SOCKET, SO_REUSEADDR, &size, sizeof (size));
  size = sizeof (server);
  memset (&server, 0, size);
  server.sin_family = AF_INET;
  server.sin_addr.s_addr = htonl (INADDR_ANY);
  server.sin_port = htons (port);

  if (bind (listenfd, (struct sockaddr *) &server, size) == -1)
    {
      syslog (LOG_ERR, "bind: %s", strerror (errno));
      exit (1);
    }

  if (listen (listenfd, 128) == -1)
    {
      syslog (LOG_ERR, "listen: %s", strerror (errno));
      exit (1);
    }

  syslog (LOG_INFO, _("GNU imap4d started"));

  for (;;)
    {
      if (children > maxchildren)
	{
	  syslog (LOG_ERR, _("Too many children (%s)"),
		  mu_umaxtostr (0, children));
	  pause ();
	  continue;
	}
      connfd = accept (listenfd, (struct sockaddr *) &client,
		       (socklen_t *) & size);
      if (connfd == -1)
	{
	  if (errno == EINTR)
	    continue;
	  syslog (LOG_ERR, "accept: %s", strerror (errno));
	  exit (1);
	}

      pid = fork ();
      if (pid == -1)
	syslog (LOG_ERR, "fork: %s", strerror (errno));
      else if (pid == 0)	/* Child.  */
	{
	  int status;
	  close (listenfd);
	  status = imap4d_mainloop (connfd,
				    fdopen (connfd, "r"),
				    fdopen (connfd, "w"));
	  closelog ();
	  exit (status);
	}
      else
	{
	  ++children;
	}
      close (connfd);
    }
}

int
imap4d_check_home_dir (const char *dir, uid_t uid, gid_t gid)
{
  struct stat st;

  if (stat (homedir, &st))
    {
      if (errno == ENOENT && create_home_dir)
	{
	  mode_t mode = umask (0);
	  int rc = mkdir (homedir, home_dir_mode);
	  umask (mode);
	  if (rc)
	    {
	      mu_error ("Cannot create home directory `%s': %s",
			homedir, mu_strerror (errno));
	      return 1;
	    }
	  if (chown (homedir, uid, gid))
	    {
	      mu_error ("Cannot set owner for home directory `%s': %s",
			homedir, mu_strerror (errno));
	      return 1;
	    }
	}
    }
  
  return 0;
}

Return to:

Send suggestions and report system problems to the System administrator.