/*****************************************************************************/
/*  pty.c - general purpose routines                                         */
/*  Copyright (C) 1998-2007 Brian Masney <masneyb@gftp.org>                  */
/*                                                                           */
/*  This program 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 of the License, or        */
/*  (at your option) any later version.                                      */
/*                                                                           */
/*  This program 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 "gftp.h"

#ifdef __sgi

char *
gftp_get_pty_impl (void)
{
  return ("sgi");
}


static int
_gftp_ptym_open (char *pts_name, size_t len, int *fds)
{
  char *new_pts_name;
  int fdm;

  if ((new_pts_name = _getpty (&fdm, O_RDWR, 0600, 0)) == NULL)
    return (GFTP_ERETRYABLE);

  strncpy (pts_name, new_pts_name, len);
  pts_name[len - 1] = '\0';

  return (fdm);
}


static int
_gftp_ptys_open (int fdm, int fds, char *pts_name)
{
  int new_fds;

  if ((new_fds = open (pts_name, O_RDWR)) < 0)
    {
      close (fdm);
      return (-1);
    }

  return (new_fds);
}

#elif HAVE_GRANTPT

#if !(defined(__FreeBSD__) || defined(__NetBSD__) || defined(__APPLE__) || defined(__linux__))
#include <stropts.h>
#endif

char *
gftp_get_pty_impl (void)
{
  return ("unix98");
}


static int
_gftp_ptym_open (char *pts_name, size_t len, int *fds)
{
  char *new_pts_name;
  void (*savesig)();
  int fdm;

  if ((fdm = open ("/dev/ptmx", O_RDWR)) < 0)
    return (GFTP_ERETRYABLE);

  savesig = signal (SIGCHLD, SIG_DFL);
  if (grantpt (fdm) < 0)
    {
      signal(SIGCHLD, savesig);
      close (fdm);
      return (GFTP_ERETRYABLE);
    }
  signal (SIGCHLD, savesig);

  if (unlockpt (fdm) < 0)
    {
      close (fdm);
      return (GFTP_ERETRYABLE);
    }

  if ((new_pts_name = ptsname (fdm)) == NULL)
    {
      close (fdm);
      return (GFTP_ERETRYABLE);
    }

  strncpy (pts_name, new_pts_name, len);
  pts_name[len - 1] = '\0';

  return (fdm);
}


static int
_gftp_ptys_open (int fdm, int fds, char *pts_name)
{
  int new_fds;

  if ((new_fds = open (pts_name, O_RDWR)) < 0)
    {
      close (fdm);
      return (-1);
    }

#if defined(SYSV) || defined (hpux)
  /* I intentionally ignore these errors */
  ioctl (new_fds, I_PUSH, "ptem");
  ioctl (new_fds, I_PUSH, "ldterm");
  ioctl (new_fds, I_PUSH, "ttcompat");
#endif

  return (new_fds);
}

#elif HAVE_OPENPTY

#ifdef HAVE_PTY_H
#include <pty.h>
#include <utmp.h> /* for login_tty */
#elif HAVE_LIBUTIL_H
#include <libutil.h>
#include <utmp.h> /* for login_tty */
#else
extern int openpty(int *amaster, int *aslave, char *name, struct termios *termp, struct winsize * winp);
extern int login_tty(int fd);
#endif

char *
gftp_get_pty_impl (void)
{
  return ("openpty");
}


static int
_gftp_ptym_open (char *pts_name, size_t len, int *fds)
{
  int fdm;

  if (openpty (&fdm, fds, pts_name, NULL, NULL) < 0)
    return (GFTP_ERETRYABLE);

  ioctl (*fds, TIOCSCTTY, NULL);

  return (fdm);
}


static int
_gftp_ptys_open (int fdm, int fds, char *pts_name)
{
  if (login_tty (fds) < 0)
    return (GFTP_EFATAL);

  return (fds);
}

#else

/* Fall back to *BSD... */

char *
gftp_get_pty_impl (void)
{
  return ("bsd");
}


static int
_gftp_ptym_open (char *pts_name, size_t len, int *fds)
{
  char *pos1, *pos2;
  int fdm;

  g_return_val_if_fail (len >= 10, GFTP_EFATAL);

  strncpy (pts_name, "/dev/ptyXY", len);
  pts_name[len - 1] = '\0';

  for (pos1 = "pqrstuvwxyzPQRST"; *pos1 != '\0'; pos1++) 
    {
      pts_name[8] = *pos1;
      for (pos2 = "0123456789abcdef"; *pos2 != '\0'; pos2++)
        {
          pts_name[9] = *pos2;
          if ((fdm = open (pts_name, O_RDWR)) < 0)
            continue;

          pts_name[5] = 't';
          chmod (pts_name, S_IRUSR | S_IWUSR);
          chown (pts_name, getuid (), -1);

          return (fdm);
        }
    }

  return (GFTP_ERETRYABLE);
}


static int
_gftp_ptys_open (int fdm, int fds, char *pts_name)
{
  int new_fds;

  if ((new_fds = open (pts_name, O_RDWR)) < 0)
    {
      close (fdm);
      return (-1);
    }

#if defined(TIOCSCTTY) && !defined(CIBAUD)
  ioctl (new_fds, TIOCSCTTY, NULL);
#endif

  return (new_fds);
}

#endif /* __sgi */


static int
_gftp_tty_raw (int fd)
{
  struct termios buf;

  if (tcgetattr (fd, &buf) < 0)
    return (-1);

  buf.c_iflag |= IGNPAR;
  buf.c_iflag &= ~(ICRNL | ISTRIP | IXON | IGNCR | IXANY | IXOFF | INLCR);
  buf.c_lflag &= ~(ECHO | ICANON | ISIG | ECHOE | ECHOK | ECHONL);
#ifdef IEXTEN
  buf.c_lflag &= ~(IEXTEN);
#endif

  buf.c_oflag &= ~(OPOST);
  buf.c_cc[VMIN] = 1;
  buf.c_cc[VTIME] = 0;

  if (tcsetattr (fd, TCSADRAIN, &buf) < 0)
    return (-1);
  return (0);
}


static void
_gftp_close_all_fds (int ptysfd)
{
  int i, maxfds;

#ifdef HAVE_GETDTABLESIZE
  maxfds = getdtablesize () - 1;
#elif defined (OPEN_MAX)
  maxfds = OPEN_MAX;
#else
  maxfds = -1;
#endif

  for (i=3; i<maxfds; i++)
    {
      if (i == ptysfd)
        continue;

      close (i);
    }
}


pid_t
gftp_exec (gftp_request * request, int *fdm, int *ptymfd, char **args)
{
  char pts_name[64];
  pid_t child;
  int ptysfd;
  int s[2];

  *pts_name = '\0';
  if ((*ptymfd = _gftp_ptym_open (pts_name, sizeof (pts_name), &ptysfd)) < 0)
    {
      request->logging_function (gftp_logging_error, request->user_data,
                                _("Cannot open master pty %s: %s\n"), pts_name,
                                g_strerror (errno));
      return (-1);
    }

  if (socketpair (AF_LOCAL, SOCK_STREAM, 0, s) < 0)
    {
      request->logging_function (gftp_logging_error, request,
                                 _("Cannot create a socket pair: %s\n"),
                                 g_strerror (errno));
      return (-1);
    }

  if ((child = fork ()) == 0)
    {
      setsid ();

      if ((ptysfd = _gftp_ptys_open (*ptymfd, ptysfd, pts_name)) < 0)
        {
          printf ("Cannot open slave pts %s: %s\n", pts_name,
                  g_strerror (errno));
          return (-1);
        }

      close (s[0]);
      close (*ptymfd);

      _gftp_tty_raw (s[1]);
      _gftp_tty_raw (ptysfd);

      dup2 (s[1], 0);
      dup2 (s[1], 1);
      dup2 (ptysfd, 2);
      _gftp_close_all_fds (ptysfd);

      execvp (args[0], args);

      printf (_("Error: Cannot execute ssh: %s\n"), g_strerror (errno));
      _exit (1);
    }
  else if (child > 0)
    {
      close (s[1]);

      *fdm = s[0];
      _gftp_tty_raw (s[0]);
      _gftp_tty_raw (*ptymfd);

      return (child);
    }
  else
    {
      request->logging_function (gftp_logging_error, request->user_data,
                                 _("Cannot fork another process: %s\n"),
                                 g_strerror (errno));
      return (-1);
    }
}

