/*

 * Copyright (c) 2010, Oracle America, Inc.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are

 * met:

 *

 *     * Redistributions of source code must retain the above copyright

 *       notice, this list of conditions and the following disclaimer.

 *     * Redistributions in binary form must reproduce the above

 *       copyright notice, this list of conditions and the following

 *       disclaimer in the documentation and/or other materials

 *       provided with the distribution.

 *     * Neither the name of the "Oracle America, Inc." nor the names of its

 *       contributors may be used to endorse or promote products derived

 *       from this software without specific prior written permission.

 *

 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS

 *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE

 *   COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,

 *   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 *   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE

 *   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

 *   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,

 *   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

 *   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

/*

 * Open two pipes to a child process, one for reading, one for writing.

 * The pipes are accessed by FILE pointers. This is NOT a public

 * interface, but for internal use only!

 */

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <string.h>

#include <rpc/rpc.h>

#include <rpc/clnt.h>

#include <libio/iolibio.h>

#define fflush(s) _IO_fflush (s)

#define __fdopen(fd,m) _IO_fdopen (fd,m)

/*

 * returns pid, or -1 for failure

 */

int

_openchild (const char *command, FILE ** fto, FILE ** ffrom)

{

  int i;

  int pid;

  int pdto[2];

  int pdfrom[2];

  if (__pipe (pdto) < 0)

    goto error1;

  if (__pipe (pdfrom) < 0)

    goto error2;

  switch (pid = __fork ())

    {

    case -1:

      goto error3;

    case 0:

      /*

       * child: read from pdto[0], write into pdfrom[1]

       */

      __close (0);

      __dup (pdto[0]);

      __close (1);

      __dup (pdfrom[1]);

      fflush (stderr);

      for (i = _rpc_dtablesize () - 1; i >= 3; i--)

	__close (i);

      fflush (stderr);

      execlp (command, command, NULL);

      perror ("exec");

      _exit (~0);

    default:

      /*

       * parent: write into pdto[1], read from pdfrom[0]

       */

      *fto = __fdopen (pdto[1], "w");

      __close (pdto[0]);

      *ffrom = __fdopen (pdfrom[0], "r");

      __close (pdfrom[1]);

      break;

    }

  return pid;

  /*

   * error cleanup and return

   */

error3:

  __close (pdfrom[0]);

  __close (pdfrom[1]);

error2:

  __close (pdto[0]);

  __close (pdto[1]);

error1:

  return -1;

}