sunrpc/openchild.c

   1 /*
   2  * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
   3  * unrestricted use provided that this legend is included on all tape
   4  * media and as a part of the software program in whole or part.  Users
   5  * may copy or modify Sun RPC without charge, but are not authorized
   6  * to license or distribute it to anyone else except as part of a product or
   7  * program developed by the user.
   8  *
   9  * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
  10  * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
  11  * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
  12  *
  13  * Sun RPC is provided with no support and without any obligation on the
  14  * part of Sun Microsystems, Inc. to assist in its use, correction,
  15  * modification or enhancement.
  16  *
  17  * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
  18  * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
  19  * OR ANY PART THEREOF.
  20  *
  21  * In no event will Sun Microsystems, Inc. be liable for any lost revenue
  22  * or profits or other special, indirect and consequential damages, even if
  23  * Sun has been advised of the possibility of such damages.
  24  *
  25  * Sun Microsystems, Inc.
  26  * 2550 Garcia Avenue
  27  * Mountain View, California  94043
  28  */
  29
  30 /*
  31  * Copyright (c) 1988 by Sun Microsystems, Inc.
  32  */
  33
  34 /*
  35  * Open two pipes to a child process, one for reading, one for writing.
  36  * The pipes are accessed by FILE pointers. This is NOT a public
  37  * interface, but for internal use only!
  38  */
  39 #include <stdio.h>
  40 #include <stdlib.h>
  41 #include <unistd.h>
  42 #include <string.h>
  43 #include <rpc/rpc.h>
  44 #include <rpc/clnt.h>
  45
  46 /*
  47  * returns pid, or -1 for failure
  48  */
  49 int
  50 _openchild (char *command, FILE ** fto, FILE ** ffrom)
  51 {
  52   int i;
  53   int pid;
  54   int pdto[2];
  55   int pdfrom[2];
  56
  57   if (pipe (pdto) < 0)
  58     goto error1;
  59   if (pipe (pdfrom) < 0)
  60     goto error2;
  61   switch (pid = fork ())
  62     {
  63     case -1:
  64       goto error3;
  65
  66     case 0:
  67       /*
  68        * child: read from pdto[0], write into pdfrom[1]
  69        */
  70       close (0);
  71       dup (pdto[0]);
  72       close (1);
  73       dup (pdfrom[1]);
  74       fflush (stderr);
  75       for (i = _rpc_dtablesize () - 1; i >= 3; i--)
  76         close (i);
  77       fflush (stderr);
  78       execlp (command, command, 0);
  79       perror ("exec");
  80       _exit (~0);
  81
  82     default:
  83       /*
  84        * parent: write into pdto[1], read from pdfrom[0]
  85        */
  86       *fto = fdopen (pdto[1], "w");
  87       close (pdto[0]);
  88       *ffrom = fdopen (pdfrom[0], "r");
  89       close (pdfrom[1]);
  90       break;
  91     }
  92   return pid;
  93
  94   /*
  95    * error cleanup and return
  96    */
  97 error3:
  98   close (pdfrom[0]);
  99   close (pdfrom[1]);
 100 error2:
 101   close (pdto[0]);
 102   close (pdto[1]);
 103 error1:
 104   return -1;
 105 }