pop3d.c 17.7 KB
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
/* GNU Mailutils -- a suite of utilities for electronic mail
   Copyright (C) 1999-2005, 2007-2012, 2014 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, see <http://www.gnu.org/licenses/>. */

#include "pop3d.h"
#include "mailutils/pam.h"
#include "mailutils/libargp.h"
#include "mailutils/pop3.h"
#include "mailutils/kwd.h"
#include "tcpwrap.h"

mu_mailbox_t mbox;
int state;
char *username;
char *md5shared;

mu_m_server_t server;
unsigned int idle_timeout;
int pop3d_transcript;
int debug_mode;
int pop3d_xlines;
char *apop_database_name = APOP_PASSFILE;
int apop_database_safety = MU_FILE_SAFETY_ALL;
uid_t apop_database_owner;
int apop_database_owner_set;

enum tls_mode tls_mode;

#ifdef WITH_TLS
int tls_available;
int tls_done;
#else
# define tls_available 0
#endif /* WITH_TLS */

int initial_state = AUTHORIZATION; 

/* Should all the messages be undeleted on startup */
int undelete_on_startup;
#ifdef ENABLE_LOGIN_DELAY
/* Minimum allowed delay between two successive logins */
time_t login_delay = 0;
char *login_stat_file = LOGIN_STAT_FILE;
#endif

unsigned expire = EXPIRE_NEVER; /* Expire messages after this number of days */
int expire_on_exit = 0;         /* Delete expired messages on exit */

static error_t pop3d_parse_opt  (int key, char *arg, struct argp_state *astate);

const char *program_version = "pop3d (" PACKAGE_STRING ")";
static char doc[] = N_("GNU pop3d -- the POP3 daemon.");

#define OPT_FOREGROUND      256

static struct argp_option options[] = {
#define GRP 0
  { "foreground", OPT_FOREGROUND, 0, 0, N_("remain in foreground"), GRP+1},
  { "inetd",  'i', 0, 0, N_("run in inetd mode"), GRP+1},
  { "daemon", 'd', N_("NUMBER"), OPTION_ARG_OPTIONAL,
    N_("runs in daemon mode with a maximum of NUMBER children"), GRP+1 },
#undef GRP

  {NULL, 0, NULL, 0, NULL, 0}
};

static int
cb_bulletin_source (void *data, mu_config_value_t *val)
{
  if (mu_cfg_assert_value_type (val, MU_CFG_STRING))
    return 1;
  set_bulletin_source (val->v.string); /* FIXME: Error reporting? */
  return 0;
}

static int
cb2_file_safety_checks (const char *name, void *data)
{
  if (mu_file_safety_compose (data, name, MU_FILE_SAFETY_ALL))
    mu_error (_("unknown keyword: %s"), name);
  return 0;
}

static int
cb_apop_safety_checks (void *data, mu_config_value_t *arg)
{
  return mu_cfg_string_value_cb (arg, cb2_file_safety_checks,
				 &apop_database_safety);
}

static int
cb_apop_database_owner (void *data, mu_config_value_t *val)
{
  struct passwd *pw;
  
  if (mu_cfg_assert_value_type (val, MU_CFG_STRING))
    return 1;
  pw = getpwnam (val->v.string);
  if (!pw)
    {
      char *p;
      unsigned long n;
    
      n = strtoul (val->v.string, &p, 10);
      if (*p)
	{
	  mu_error (_("no such user: %s"), val->v.string);
	  return 1;
	}
      apop_database_owner = n;
    }
  else
    apop_database_owner = pw->pw_uid;
  apop_database_owner_set = 1;
  return 0;
}

#ifdef ENABLE_DBM
static int
cb_bulletin_db (void *data, mu_config_value_t *val)
{
  if (mu_cfg_assert_value_type (val, MU_CFG_STRING))
    return 1;
  set_bulletin_db (val->v.string); /* FIXME: Error reporting? */
  return 0;
}
#endif

struct pop3d_srv_config
{
  struct mu_srv_config m_cfg;
  enum tls_mode tls_mode;
};

#ifdef WITH_TLS
static int
cb_tls (void *data, mu_config_value_t *val)
{
  int *res = data;
  static struct mu_kwd tls_kwd[] = {
    { "no", tls_no },
    { "false", tls_no },
    { "off", tls_no },
    { "0", tls_no },
    { "ondemand", tls_ondemand },
    { "stls", tls_ondemand },
    { "required", tls_required },
    { "connection", tls_connection },
    /* For compatibility with prior versions: */
    { "yes", tls_connection }, 
    { "true", tls_connection },
    { "on", tls_connection },
    { "1", tls_connection },
    { NULL }
  };
  
  if (mu_cfg_assert_value_type (val, MU_CFG_STRING))
    return 1;

  if (mu_kwd_xlat_name (tls_kwd, val->v.string, res))
    mu_error (_("not a valid tls keyword: %s"), val->v.string);
  return 0;
}

static int
cb_tls_required (void *data, mu_config_value_t *val)
{
  int bv;
  
  if (mu_cfg_assert_value_type (val, MU_CFG_STRING))
    return 1;
  if (mu_cfg_parse_boolean (val->v.string, &bv))
    mu_error (_("Not a boolean value"));
  else if (bv)
    {
      tls_mode = tls_required;
      mu_diag_output (MU_DIAG_WARNING,
		      "the \"tls-required\" statement is deprecated, "
		      "use \"tls required\" instead");
    }
  else
    mu_diag_output (MU_DIAG_WARNING,
		    "the \"tls-required\" statement is deprecated, "
		    "use \"tls\" instead");

  return 0;
}
#endif

static struct mu_cfg_param pop3d_srv_param[] = {
#ifdef WITH_TLS
  { "tls", mu_cfg_callback,
    NULL, mu_offsetof (struct pop3d_srv_config, tls_mode), cb_tls,
    N_("Kind of TLS encryption to use for this server") },
#endif
  { NULL }
};
    
static struct mu_cfg_param pop3d_cfg_param[] = {
  { "undelete", mu_cfg_bool, &undelete_on_startup, 0, NULL,
    N_("On startup, clear deletion marks from all the messages.") },
  { "expire", mu_cfg_uint, &expire, 0, NULL,
    N_("Automatically expire read messages after the given number of days."),
    N_("days") },
  { "delete-expired", mu_cfg_bool, &expire_on_exit, 0, NULL,
    N_("Delete expired messages upon closing the mailbox.") },
  { "scan-lines", mu_cfg_bool, &pop3d_xlines, 0, NULL,
    N_("Output the number of lines in the message in its scan listing.") },
  { "apop-database-file", mu_cfg_string, &apop_database_name, 0, NULL,
    N_("set APOP database file name or URL") },
  { "apop-database-owner", mu_cfg_callback, NULL, 0, cb_apop_database_owner,
    N_("Name or UID of the APOP database owner") },
  { "apop-database-safety", mu_cfg_callback, NULL, 0, cb_apop_safety_checks,
    N_("Configure safety checks for APOP database files.  Argument is a list or "
       "sequence of check names optionally prefixed with '+' to enable or "
       "'-' to disable the corresponding check.  Valid check names are:\n"
       "\n"
       "  none          disable all checks\n"
       "  all           enable all checks\n"
       "  gwrfil        forbid group writable files\n"
       "  awrfil        forbid world writable files\n"
       "  grdfil        forbid group readable files\n"
       "  ardfil        forbid world writable files\n"
       "  linkwrdir     forbid symbolic links in group or world writable directories\n"
       "  gwrdir        forbid files in group writable directories\n"
       "  awrdir        forbid files in world writable directories\n"),
    N_("arg: list") },  
    
#ifdef WITH_TLS
  { "tls", mu_cfg_callback, &tls_mode, 0, cb_tls,
    N_("Kind of TLS encryption to use") },
  { "tls-required", mu_cfg_callback, &tls_mode, 0, cb_tls_required,
    N_("Always require STLS before entering authentication phase.\n"
       "Deprecated, use \"tls required\" instead.") },
#endif
#ifdef ENABLE_LOGIN_DELAY
  { "login-delay", mu_cfg_time, &login_delay, 0, NULL,
    N_("Set the minimal allowed delay between two successive logins.") },
  { "stat-file", mu_cfg_string, &login_stat_file, 0, NULL,
    N_("Set the name of login statistics file (for login-delay).") },
#endif
  { "bulletin-source", mu_cfg_callback, NULL, 0, cb_bulletin_source,
    N_("Get bulletins from the specified mailbox."),
    N_("url") },
#ifdef ENABLE_DBM
  { "bulletin-db", mu_cfg_callback, NULL, 0, cb_bulletin_db,
    N_("Set the bulletin database file name."),
    N_("file") },
#endif
  { "output-buffer-size", mu_cfg_size, &pop3d_output_bufsize, 0, NULL,
    N_("Size of the output buffer.") },
  { "mandatory-locking", mu_cfg_section },
  { ".server", mu_cfg_section, NULL, 0, NULL,
    N_("Server configuration.") },
  { "transcript", mu_cfg_bool, &pop3d_transcript, 0, NULL,
    N_("Set global transcript mode.") },
  TCP_WRAPPERS_CONFIG
  { NULL }
};
    
static struct argp argp = {
  options,
  pop3d_parse_opt,
  NULL,
  doc,
  NULL,
  NULL, NULL
};

static const char *pop3d_argp_capa[] = {
  "auth",
  "common",
  "debug",
  "mailbox",
  "locking",
  "logging",
  NULL
};

static error_t
pop3d_parse_opt (int key, char *arg, struct argp_state *astate)
{
  static mu_list_t lst;
  
  switch (key)
    {
    case 'd':
      mu_argp_node_list_new (lst, "mode", "daemon");
      if (arg)
	mu_argp_node_list_new (lst, "max-children", arg);
      break;

    case 'i':
      mu_argp_node_list_new (lst, "mode", "inetd");
      break;

    case OPT_FOREGROUND:
      mu_argp_node_list_new (lst, "foreground", "yes");
      break;
      
    case ARGP_KEY_INIT:
      mu_argp_node_list_init (&lst);
      break;
      
    case ARGP_KEY_FINI:
      mu_argp_node_list_finish (lst, NULL, NULL);
      break;
      
    default:
      return ARGP_ERR_UNKNOWN;
    }
  return 0;
}

int
pop3d_get_client_address (int fd, struct sockaddr_in *pcs)
{
  mu_diag_output (MU_DIAG_INFO, _("incoming connection opened"));

  /* log information on the connecting client. */
  if (debug_mode)
    {
      mu_diag_output (MU_DIAG_INFO, _("started in debugging mode"));
      return 1;
    }
  else
    {
      socklen_t len = sizeof *pcs;
      if (getpeername (fd, (struct sockaddr*) pcs, &len) < 0)
	{
	  mu_diag_output (MU_DIAG_ERROR,
			  _("cannot obtain IP address of client: %s"),
			  strerror (errno));
	  return 1;
	}
    }
  return 0;
}

/* The main part of the daemon. This function reads input from the client and
   executes the proper functions. Also handles the bulk of error reporting.
   Arguments:
      ifd       --  input descriptor
      ofd       --  output descriptor
      tls       --  initiate encrypted connection */
int
pop3d_mainloop (int ifd, int ofd, enum tls_mode tls)
{
  int status = OK;
  char buffer[512];
  static int sigtab[] = { SIGILL, SIGBUS, SIGFPE, SIGSEGV, SIGSTOP, SIGPIPE,
			  SIGABRT, SIGINT, SIGQUIT, SIGTERM, SIGHUP, SIGALRM };
  struct pop3d_session session;
     
  mu_set_signals (pop3d_child_signal, sigtab, MU_ARRAY_SIZE (sigtab));

  if (tls == tls_unspecified)
    tls = tls_available ? tls_ondemand : tls_no;
  else if (tls != tls_no && !tls_available)
    {
      mu_error (_("TLS is not configured, but requested in the "
		  "configuration"));
      tls = tls_no;
    }
  
  pop3d_setio (ifd, ofd, tls == tls_connection);

  if (tls == tls_required)
    initial_state = INITIAL;
  
  state = tls == tls_connection ? AUTHORIZATION : initial_state;

  pop3d_session_init (&session);
  session.tls = tls;
  /* FIXME: state should also be in the session? */
  
  /* Prepare the shared secret for APOP.  */
  {
    char *local_hostname;
    
    status = mu_get_host_name (&local_hostname);
    if (status)
      {
        mu_diag_funcall (MU_DIAG_ERROR, "mu_get_host_name", NULL, status);
        exit (EXIT_FAILURE);
      }

    md5shared = mu_alloc (strlen (local_hostname) + 51);

    snprintf (md5shared, strlen (local_hostname) + 50, "<%u.%u@%s>", getpid (),
	      (unsigned)time (NULL), local_hostname);
    free (local_hostname);
  }

  /* Lets boogie.  */
  pop3d_outf ("+OK POP3 Ready %s\n", md5shared);

  while (state != UPDATE && state != ABORT)
    {
      char *buf;
      char *arg, *cmd;
      pop3d_command_handler_t handler;
      
      pop3d_flush_output ();
      status = OK;
      buf = pop3d_readline (buffer, sizeof (buffer));
      pop3d_parse_command (buf, &cmd, &arg);

      if (state == TRANSACTION && !mu_mailbox_is_updated (mbox))
	{
	  static mu_off_t mailbox_size;
	  mu_off_t newsize = 0;
	  mu_mailbox_get_size (mbox, &newsize);
	  /* Did we shrink?  First time save the size.  */
	  if (!mailbox_size)
	    mailbox_size = newsize;
	  else if (newsize < mailbox_size) /* FIXME: Should it be a != ? */
	    pop3d_abquit (ERR_MBOX_SYNC); /* Out of sync, Bail out.  */
	}

      /* Refresh the Lock.  */
      manlock_touchlock (mbox);

      if ((handler = pop3d_find_command (cmd)) != NULL)
	status = handler (arg, &session);
      else
	status = ERR_BAD_CMD;

      if (status != OK)
	pop3d_outf ("-ERR %s\n", pop3d_error_string (status));
    }

  pop3d_session_free (&session);
  
  pop3d_bye ();

  return status;
}

static int
set_strerr_flt ()
{
  mu_stream_t flt, trans[2];
  int rc;
  
  rc = mu_stream_ioctl (mu_strerr, MU_IOCTL_TOPSTREAM, MU_IOCTL_OP_GET, trans);
  if (rc == 0)
    {
      char sessidstr[10];
      char *argv[] = { "inline-comment", NULL, "-S", NULL };

      snprintf (sessidstr, sizeof sessidstr, "%08lx:", mu_session_id);
      argv[1] = sessidstr;
      rc = mu_filter_create_args (&flt, trans[0], "inline-comment", 3,
				  (const char **)argv,
				  MU_FILTER_ENCODE, MU_STREAM_WRITE);
      mu_stream_unref (trans[0]);
      if (rc == 0)
	{
	  mu_stream_set_buffer (flt, mu_buffer_line, 0);
	  trans[0] = flt;
	  trans[1] = NULL;
	  rc = mu_stream_ioctl (mu_strerr, MU_IOCTL_TOPSTREAM,
				MU_IOCTL_OP_SET, trans);
	  mu_stream_unref (trans[0]);
	  if (rc)
	    mu_error (_("%s failed: %s"), "MU_IOCTL_SET_STREAM",
		      mu_stream_strerror (mu_strerr, rc));
	}
      else
	mu_error (_("cannot create log filter stream: %s"), mu_strerror (rc));
    }
  else
    {
      mu_error (_("%s failed: %s"), "MU_IOCTL_GET_STREAM",
		mu_stream_strerror (mu_strerr, rc));
    }
  return rc;
}

static void
clr_strerr_flt ()
{
  mu_stream_t flt, trans[2];
  int rc;

  rc = mu_stream_ioctl (mu_strerr, MU_IOCTL_TOPSTREAM, MU_IOCTL_OP_GET, trans);
  if (rc == 0)
    {
      flt = trans[0];

      rc = mu_stream_ioctl (flt, MU_IOCTL_TOPSTREAM, MU_IOCTL_OP_GET, trans);
      if (rc == 0)
	{
	  mu_stream_unref (trans[0]);
	  rc = mu_stream_ioctl (mu_strerr, MU_IOCTL_TOPSTREAM,
				MU_IOCTL_OP_SET, trans);
	  if (rc == 0)
	    mu_stream_unref (flt);
	}
    }
}

int
pop3d_connection (int fd, struct sockaddr *sa, int salen,
		  struct mu_srv_config *pconf,
		  void *data)
{
  struct pop3d_srv_config *cfg = (struct pop3d_srv_config *) pconf;
  int rc;
  
  idle_timeout = pconf->timeout;
  pop3d_transcript = pconf->transcript;

  if (mu_log_session_id)
    rc = set_strerr_flt ();
  else
    rc = 1;

  pop3d_mainloop (fd, fd,
		  cfg->tls_mode == tls_unspecified ? tls_mode : cfg->tls_mode);

  if (rc == 0)
    clr_strerr_flt ();
  return 0;
}

static void
pop3d_alloc_die ()
{
  pop3d_abquit (ERR_NO_MEM);
}

#ifdef ENABLE_DBM
static void
set_dbm_safety ()
{
  mu_url_t hints = mu_dbm_get_hint ();
  const char *param[] = { "+all" };
  mu_url_add_param (hints, 1, param);
}
#endif

int
main (int argc, char **argv)
{
  struct group *gr;
  int status = OK;
  static int sigtab[] = { SIGILL, SIGBUS, SIGFPE, SIGSEGV, SIGSTOP, SIGPIPE };

  /* Native Language Support */
  MU_APP_INIT_NLS ();

  MU_AUTH_REGISTER_ALL_MODULES();
  /* Register the desired formats.  */
  mu_register_local_mbox_formats ();

#ifdef WITH_TLS
  mu_gocs_register ("tls", mu_tls_module_init);
#endif /* WITH_TLS */
  mu_tcpwrapper_cfg_init ();
  manlock_cfg_init ();
  mu_acl_cfg_init ();
  mu_m_server_cfg_init (pop3d_srv_param);
  
  mu_argp_init (NULL, NULL);
  	
  mu_m_server_create (&server, program_version);
  mu_m_server_set_config_size (server, sizeof (struct pop3d_srv_config));
  mu_m_server_set_conn (server, pop3d_connection);
  mu_m_server_set_prefork (server, mu_tcp_wrapper_prefork);
  mu_m_server_set_mode (server, MODE_INTERACTIVE);
  mu_m_server_set_max_children (server, 20);
  /* FIXME mu_m_server_set_pidfile (); */
  mu_m_server_set_default_port (server, 110);
  mu_m_server_set_timeout (server, 600);
  mu_m_server_set_strexit (server, mu_strexit);

  mu_alloc_die_hook = pop3d_alloc_die;

  mu_log_syslog = 1;
  manlock_mandatory_locking = 1;

#ifdef ENABLE_DBM
  set_dbm_safety ();
#endif
  
  if (mu_app_init (&argp, pop3d_argp_capa, pop3d_cfg_param, 
		   argc, argv, 0, NULL, server))
    exit (EX_CONFIG); /* FIXME: No way to discern from EX_USAGE? */

  if (expire == 0)
    expire_on_exit = 1;

#ifdef USE_LIBPAM
  if (!mu_pam_service)
    mu_pam_service = "gnu-pop3d";
#endif

  if (mu_m_server_mode (server) == MODE_INTERACTIVE && isatty (0))
    {
      /* If input is a tty, switch to debug mode */
      debug_mode = 1;
    }
  else
    {
      errno = 0;
      gr = getgrnam ("mail");
      if (gr == NULL)
	{
	  if (errno == 0 || errno == ENOENT)
            {
               mu_error (_("%s: no such group"), "mail");
               exit (EX_CONFIG);
            }
          else
            {
	      mu_diag_funcall (MU_DIAG_ERROR, "getgrnam", "mail", errno);
	      exit (EX_OSERR);
            }
	}

      if (setgid (gr->gr_gid) == -1)
	{
	  mu_error (_("error setting mail group: %s"), mu_strerror (errno));
	  exit (EX_OSERR);
	}
    }

  /* Set the signal handlers.  */
  mu_set_signals (pop3d_master_signal, sigtab, MU_ARRAY_SIZE (sigtab));

  mu_stdstream_strerr_setup (mu_log_syslog ?
			     MU_STRERR_SYSLOG : MU_STRERR_STDERR);
  
  umask (S_IROTH | S_IWOTH | S_IXOTH);	/* 007 */

  /* Check TLS environment, i.e. cert and key files */
#ifdef WITH_TLS
  tls_available = mu_check_tls_environment ();
  if (tls_available)
    {
      tls_available = mu_init_tls_libs (1);
      if (tls_available)
	enable_stls ();
    }
#endif /* WITH_TLS */

  /* Actually run the daemon.  */
  if (mu_m_server_mode (server) == MODE_DAEMON)
    {
      mu_m_server_begin (server);
      status = mu_m_server_run (server);
      mu_m_server_end (server);
      mu_m_server_destroy (&server);
    }
  else
    {
      /* Make sure we are in the root directory.  */
      chdir ("/");
      status = pop3d_mainloop (MU_STDIN_FD, MU_STDOUT_FD, tls_mode);
    }
  
  if (status)
    mu_error (_("main loop status: %s"), mu_strerror (status));	  
  /* Close the syslog connection and exit.  */
  closelog ();
  return status ? EX_SOFTWARE : EX_OK;
}