1  /*
       2   * Copyright (c) 2010, Oracle America, Inc.
       3   *
       4   * Redistribution and use in source and binary forms, with or without
       5   * modification, are permitted provided that the following conditions are
       6   * met:
       7   *
       8   *     * Redistributions of source code must retain the above copyright
       9   *       notice, this list of conditions and the following disclaimer.
      10   *     * Redistributions in binary form must reproduce the above
      11   *       copyright notice, this list of conditions and the following
      12   *       disclaimer in the documentation and/or other materials
      13   *       provided with the distribution.
      14   *     * Neither the name of the "Oracle America, Inc." nor the names of its
      15   *       contributors may be used to endorse or promote products derived
      16   *       from this software without specific prior written permission.
      17   *
      18   *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
      19   *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
      20   *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
      21   *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
      22   *   COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
      23   *   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
      24   *   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
      25   *   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
      26   *   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
      27   *   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
      28   *   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
      29   *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
      30   */
      31  
      32  /*
      33   * Open two pipes to a child process, one for reading, one for writing.
      34   * The pipes are accessed by FILE pointers. This is NOT a public
      35   * interface, but for internal use only!
      36   */
      37  #include <stdio.h>
      38  #include <stdlib.h>
      39  #include <unistd.h>
      40  #include <string.h>
      41  #include <rpc/rpc.h>
      42  #include <rpc/clnt.h>
      43  
      44  #include <libio/iolibio.h>
      45  #define fflush(s) _IO_fflush (s)
      46  #define __fdopen(fd,m) _IO_fdopen (fd,m)
      47  
      48  /*
      49   * returns pid, or -1 for failure
      50   */
      51  int
      52  _openchild (const char *command, FILE ** fto, FILE ** ffrom)
      53  {
      54    int i;
      55    int pid;
      56    int pdto[2];
      57    int pdfrom[2];
      58  
      59    if (__pipe (pdto) < 0)
      60      goto error1;
      61    if (__pipe (pdfrom) < 0)
      62      goto error2;
      63    switch (pid = __fork ())
      64      {
      65      case -1:
      66        goto error3;
      67  
      68      case 0:
      69        /*
      70         * child: read from pdto[0], write into pdfrom[1]
      71         */
      72        __close (0);
      73        __dup (pdto[0]);
      74        __close (1);
      75        __dup (pdfrom[1]);
      76        fflush (stderr);
      77        for (i = _rpc_dtablesize () - 1; i >= 3; i--)
      78  	__close (i);
      79        fflush (stderr);
      80        execlp (command, command, NULL);
      81        perror ("exec");
      82        _exit (~0);
      83  
      84      default:
      85        /*
      86         * parent: write into pdto[1], read from pdfrom[0]
      87         */
      88        *fto = __fdopen (pdto[1], "w");
      89        __close (pdto[0]);
      90        *ffrom = __fdopen (pdfrom[0], "r");
      91        __close (pdfrom[1]);
      92        break;
      93      }
      94    return pid;
      95  
      96    /*
      97     * error cleanup and return
      98     */
      99  error3:
     100    __close (pdfrom[0]);
     101    __close (pdfrom[1]);
     102  error2:
     103    __close (pdto[0]);
     104    __close (pdto[1]);
     105  error1:
     106    return -1;
     107  }