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 #ifdef USE_IN_LIBIO
  47 # include <libio/iolibio.h>
  48 # define fflush(s) _IO_fflush (s)
  49 #endif
  50
  51 /*
  52  * returns pid, or -1 for failure
  53  */
  54 int
  55 _openchild (char *command, FILE ** fto, FILE ** ffrom)
  56 {
  57   int i;
  58   int pid;
  59   int pdto[2];
  60   int pdfrom[2];
  61
  62   if (__pipe (pdto) < 0)
  63     goto error1;
  64   if (__pipe (pdfrom) < 0)
  65     goto error2;
  66   switch (pid = __fork ())
  67     {
  68     case -1:
  69       goto error3;
  70
  71     case 0:
  72       /*
  73        * child: read from pdto[0], write into pdfrom[1]
  74        */
  75       __close (0);
  76       __dup (pdto[0]);
  77       __close (1);
  78       __dup (pdfrom[1]);
  79       fflush (stderr);
  80       for (i = _rpc_dtablesize () - 1; i >= 3; i--)
  81         __close (i);
  82       fflush (stderr);
  83       execlp (command, command, 0);
  84       perror ("exec");
  85       _exit (~0);
  86
  87     default:
  88       /*
  89        * parent: write into pdto[1], read from pdfrom[0]
  90        */
  91       *fto = fdopen (pdto[1], "w");
  92       __close (pdto[0]);
  93       *ffrom = fdopen (pdfrom[0], "r");
  94       __close (pdfrom[1]);
  95       break;
  96     }
  97   return pid;
  98
  99   /*
 100    * error cleanup and return
 101    */
 102 error3:
 103   __close (pdfrom[0]);
 104   __close (pdfrom[1]);
 105 error2:
 106   __close (pdto[0]);
 107   __close (pdto[1]);
 108 error1:
 109   return -1;
 110 }