sunrpc/openchild.c

   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 }