git.sur5r.net Git - openldap/blob - servers/slapd/back-shell/fork.c

   1 /* fork.c - fork and exec a process, connecting stdin/out w/pipes */
   2 /* $OpenLDAP$ */
   3 /*
   4  * Copyright 1998-2002 The OpenLDAP Foundation, All Rights Reserved.
   5  * COPYING RESTRICTIONS APPLY, see COPYRIGHT file
   6  */
   7
   8 #include "portable.h"
   9
  10 #include <stdio.h>
  11
  12 #include <ac/errno.h>
  13 #include <ac/string.h>
  14 #include <ac/socket.h>
  15 #include <ac/unistd.h>
  16
  17 #include "slap.h"
  18 #include "shell.h"
  19
  20 pid_t
  21 forkandexec(
  22     char        **args,
  23     FILE        **rfp,
  24     FILE        **wfp
  25 )
  26 {
  27         int     p2c[2] = { -1, -1 }, c2p[2];
  28         pid_t   pid;
  29
  30         if ( pipe( p2c ) != 0 || pipe( c2p ) != 0 ) {
  31                 Debug( LDAP_DEBUG_ANY, "pipe failed\n", 0, 0, 0 );
  32                 close( p2c[0] );
  33                 close( p2c[1] );
  34                 return( -1 );
  35         }
  36
  37         /*
  38          * what we're trying to set up looks like this:
  39          *      parent *wfp -> p2c[1] | p2c[0] -> stdin child
  40          *      parent *rfp <- c2p[0] | c2p[1] <- stdout child
  41          */
  42
  43         fflush( NULL );
  44 # ifdef HAVE_THR
  45         pid = fork1();
  46 # else
  47         pid = fork();
  48 # endif
  49         if ( pid == 0 ) {               /* child */
  50                 /*
  51                  * child could deadlock here due to resources locked
  52                  * by our parent
  53                  *
  54                  * If so, configure --without-threads.
  55                  */
  56                 if ( dup2( p2c[0], 0 ) == -1 || dup2( c2p[1], 1 ) == -1 ) {
  57                         Debug( LDAP_DEBUG_ANY, "dup2 failed\n", 0, 0, 0 );
  58                         exit( EXIT_FAILURE );
  59                 }
  60         }
  61         close( p2c[0] );
  62         close( c2p[1] );
  63         if ( pid <= 0 ) {
  64                 close( p2c[1] );
  65                 close( c2p[0] );
  66         }
  67         switch ( pid ) {
  68         case 0:
  69                 execv( args[0], args );
  70
  71                 Debug( LDAP_DEBUG_ANY, "execv failed\n", 0, 0, 0 );
  72                 exit( EXIT_FAILURE );
  73
  74         case -1:        /* trouble */
  75                 Debug( LDAP_DEBUG_ANY, "fork failed\n", 0, 0, 0 );
  76                 return( -1 );
  77         }
  78
  79         /* parent */
  80         if ( (*rfp = fdopen( c2p[0], "r" )) == NULL || (*wfp = fdopen( p2c[1],
  81             "w" )) == NULL ) {
  82                 Debug( LDAP_DEBUG_ANY, "fdopen failed\n", 0, 0, 0 );
  83                 close( c2p[0] );
  84                 close( p2c[1] );
  85
  86                 return( -1 );
  87         }
  88
  89         return( pid );
  90 }