/* Copyright © 2006-2013  Roger Leigh <rleigh@debian.org>
 *
 * schroot 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 of the License, or
 * (at your option) any later version.
 *
 * schroot 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, see
 * <http://www.gnu.org/licenses/>.
 *
 *********************************************************************/

#include <config.h>

#include <sbuild/ctty.h>

#include <cerrno>
#include <cstring>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

namespace sbuild
{

  namespace
  {

    /**
     * Set close-on-exec flag.  An error will be thrown on failure.
     *
     * @param fd the file descriptor to set.
     */
    void
    set_cloexec (int fd)
    {
      int flags = fcntl(fd, F_GETFD);
      flags |= FD_CLOEXEC;
      if (fcntl(fd, F_SETFD, flags) < 0)
        throw ctty_error(CTTY_CLOEXEC, strerror(errno));
    }

    /**
     * Open the controlling terminal and return its file descriptor.
     *
     * @returns the CTTY fd, or -1 on failure.
     */
    int
    open_ctty ()
    {
      int ctty = open("/dev/tty", O_RDWR|O_NOCTTY);
      if (ctty >= 0)
        {
          set_cloexec(ctty);
        }
      else
        {
          ctty = -1;
        }

      return ctty;
    }

  }

  template<>
  error<ctty_error_code>::map_type
  error<ctty_error_code>::error_strings =
    {
      {sbuild::CTTY_CLOEXEC, N_("The controlling terminal close-on-execute flag could not be set")},
      {sbuild::CTTY_DUP,     N_("The controlling terminal file descriptor could not be duplicated")}
    };

  const int CTTY_FILENO(open_ctty());

  namespace
  {

    /**
     * Get the file descriptor for cttybuf.  An error will be thrown on
     * failure.
     *
     * @returns the CTTY_FILENO file descriptor if there is a CTTY, or a
     * duplicated file descriptor for stdin otherwise.
     */
    int
    cttybuf_fd ()
    {
      int ctty = CTTY_FILENO;

      if (ctty < 0)
        {
          ctty = dup(STDIN_FILENO);

          if (ctty < 0)
            throw ctty_error(CTTY_DUP, strerror(errno));

          set_cloexec(ctty);
        }

      return ctty;
    }

    /// A streambuf for cctty.
    //  boost::iostreams::file_descriptor cttybuf(cttybuf_fd(), close_handle);

  }

#ifdef BOOST_IOSTREAMS_CLOSE_HANDLE_OLD
  fdstream cctty(cttybuf_fd(), true);
#else
  fdstream cctty(cttybuf_fd(), boost::iostreams::close_handle);
#endif

}