/* Stubby version of getty for Hurd

   Copyright (C) 1996, 1998, 1999, 2007, 2014
     Free Software Foundation, Inc.

   Written by Michael I. Bushnell, p/BSG.

   This file is part of the GNU Hurd.

   The GNU Hurd 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.

   The GNU Hurd 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 this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA. */

#include <syslog.h>
#include <unistd.h>
#include <ttyent.h>
#include <stdio.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <errno.h>
#include <error.h>
#include <sys/utsname.h>
#include <stdlib.h>
#include <string.h>
#include <utmp.h>
#include <sys/ioctl.h>
#include <termios.h>
#include <assert-backtrace.h>

/* XXX: should include directly from libshouldbeinlibc */
extern char *localhost (void);

#define _PATH_LOGIN "/bin/login"
#define _PATH_ISSUE "/etc/issue"

/* Parse the terminal speed.  */
static void
set_speed (int tty, char *speedstr)
{
  error_t err;
  struct termios ttystat;
  speed_t speed;
  char *tail;

  errno = 0;
  speed = strtoul (speedstr, &tail, 0);
  if (errno || *tail)
    return;

  err = tcgetattr (tty, &ttystat);
  if (!err && !cfsetspeed (&ttystat, speed))
    tcsetattr (tty, TCSAFLUSH, &ttystat);
}

/* Load a banner from _PATH_ISSUE.  If that fails, a built-in version
   is provided.  */
static char *
load_banner (void)
{
  char *buf = NULL, *p;
  struct stat st;
  int fd = -1;
  ssize_t remaining, count;

  fd = open (_PATH_ISSUE, O_RDONLY);
  if (fd == -1)
    goto out;

  if (fstat (fd, &st) == -1)
    goto out;

  buf = malloc (st.st_size + 1);
  if (buf == NULL)
    goto out;

  remaining = st.st_size;
  p = buf;
  while (remaining > 0)
    {
      count = read (fd, p, remaining);
      if (count == -1)
        {
          close (fd);
          goto out;
        }
      p += count;
      remaining -= count;
    }

  buf[st.st_size] = '\0';
  close (fd);
  return buf;

 out:
  if (fd != -1)
    close (fd);
  free (buf);
  return "\n\\s \\r (\\n) (\\l)\r\n\n";
}

/* Print a suitable welcome banner */
static void
print_banner (int fd, char *ttyname)
{
  ssize_t err;
  char *s, *t, *expansion;
  struct utsname u;
  size_t len;

  if (uname (&u))
    u.sysname[0] = u.release[0] = '\0';

  err = write (fd, "\r\n", 2);
  assert_backtrace (err == 2);
  for (s = load_banner (); *s; s++)
    {
      for (t = s; *t && *t != '\\'; t++) /* nomnomnom */;

      err = write (fd, s, t - s);
      assert_backtrace (err == (t - s));
      if (! *t)
        return;

      switch (*(t + 1))
        {
        case '\\':
          expansion = "\\";
          break;
        case 's':
          expansion = u.sysname;
          break;
        case 'r':
          expansion = u.release;
          break;
        case 'n':
          expansion = localhost () ?: "?";
          break;
        case 'l':
          expansion = basename (ttyname);
          break;
        default:
          expansion = "?";
        }
      len = strlen (expansion);
      err = write (fd, expansion, len);
      assert_backtrace (err == len);

      s = t + 1;
    }
}

int
main (int argc, char **argv)
{
  int err;
  char *linespec, *ttyname;
  int tty;
  struct ttyent *tt;
  char *arg;
  char *autologin_option = NULL, *autologin = NULL;

  openlog ("getty", LOG_ODELAY|LOG_CONS|LOG_PID, LOG_AUTH);

  while (argc >= 2)
    {
      if (strcmp (argv[1], "--noclear") == 0)
	{
	  /* We don't actually clear anyway.  */
	  argc--;
	  argv++;
	}
      else if (argc >= 3 &&
		 (strcmp (argv[1], "-a") == 0
		  || strcmp (argv[1], "--autologin") == 0))
	{
	  /* Auto-login */
	  autologin_option = "-f";
	  autologin = argv[2];
	  argc -= 2;
	  argv += 2;
	}
      else
	break;
    }

  /* Nothing to do .... */
  if (argc != 3)
    {
      syslog (LOG_ERR, "Bad syntax");
      closelog ();
      exit (1);
    }

  /* Don't do anything with this for now. */
  linespec = argv[1];

  tt = getttynam (argv[2]);
  err = asprintf (&ttyname, "%s/%s", _PATH_DEV, argv[2]);
  if (err == -1)
    {
      syslog (LOG_ERR, "asprintf failed %s: %m", argv[2]);
      closelog ();
      exit (1);
    }

  err = chown (ttyname, 0, 0);
  if (err == -1)
    {
      syslog (LOG_ERR, "chown failed %s: %m", ttyname);
      closelog ();
      exit (1);
    }
  err = chmod (ttyname, 0600);
  if (err == -1)
    {
      syslog (LOG_ERR, "chmod failed %s: %m", ttyname);
      closelog ();
      exit (1);
    }
  err = revoke (ttyname);
  if (err == -1)
    {
      syslog (LOG_ERR, "revoke failed %s; %m", ttyname);
      closelog ();
      exit (1);
    }
  sleep (2);			/* leave DTR down for a bit */

  do
    {
      tty = open (ttyname, O_RDWR);
      if (tty == -1)
	{
	  syslog (LOG_ERR, "%s: %m", ttyname);
	  closelog ();
	  sleep (60);
	}
    }
  while (tty == -1);

  set_speed (tty, linespec);

  print_banner (tty, ttyname);

  if (login_tty (tty) == -1)
    syslog (LOG_ERR, "cannot set controlling terminal to %s: %m", ttyname);

  err = asprintf (&arg, "TERM=%s", tt ? tt->ty_type : "unknown");
  if (err == -1)
    {
      syslog (LOG_ERR, "asprintf failed %s: %m", ttyname);
      closelog ();
      exit (1);
    }

  if (tt && strcmp (tt->ty_type, "dialup") == 0)
    /* Dialup lines time out (which is login's default).  */
    execl (_PATH_LOGIN, "login", "-e", arg, autologin_option, autologin, NULL);
  else
    /* Hardwired lines don't.  */
    execl (_PATH_LOGIN, "login", "-e", arg, "-aNOAUTH_TIMEOUT", autologin_option, autologin, NULL);

  syslog (LOG_ERR, "%s: %m", _PATH_LOGIN);

  return 1;
}
