sunrpc/openchild.c

   1 /*
   2  * Copyright (c) 1988 by Sun Microsystems, 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 Sun Microsystems, 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 #ifdef USE_IN_LIBIO
  45 # include <libio/iolibio.h>
  46 # define fflush(s) INTUSE(_IO_fflush) (s)
  47 # define __fdopen(fd,m) INTUSE(_IO_fdopen) (fd,m)
  48 #endif
  49
  50 /*
  51  * returns pid, or -1 for failure
  52  */
  53 int
  54 _openchild (const char *command, FILE ** fto, FILE ** ffrom)
  55 {
  56   int i;
  57   int pid;
  58   int pdto[2];
  59   int pdfrom[2];
  60
  61   if (__pipe (pdto) < 0)
  62     goto error1;
  63   if (__pipe (pdfrom) < 0)
  64     goto error2;
  65   switch (pid = __fork ())
  66     {
  67     case -1:
  68       goto error3;
  69
  70     case 0:
  71       /*
  72        * child: read from pdto[0], write into pdfrom[1]
  73        */
  74       __close (0);
  75       __dup (pdto[0]);
  76       __close (1);
  77       __dup (pdfrom[1]);
  78       fflush (stderr);
  79       for (i = _rpc_dtablesize () - 1; i >= 3; i--)
  80         __close (i);
  81       fflush (stderr);
  82       execlp (command, command, NULL);
  83       perror ("exec");
  84       _exit (~0);
  85
  86     default:
  87       /*
  88        * parent: write into pdto[1], read from pdfrom[0]
  89        */
  90       *fto = __fdopen (pdto[1], "w");
  91       __close (pdto[0]);
  92       *ffrom = __fdopen (pdfrom[0], "r");
  93       __close (pdfrom[1]);
  94       break;
  95     }
  96   return pid;
  97
  98   /*
  99    * error cleanup and return
 100    */
 101 error3:
 102   __close (pdfrom[0]);
 103   __close (pdfrom[1]);
 104 error2:
 105   __close (pdto[0]);
 106   __close (pdto[1]);
 107 error1:
 108   return -1;
 109 }