close stdin before dup-ing, check return value of dup2

diff --git a/src/transport/gnunet_wlan_sender.c b/src/transport/gnunet_wlan_sender.c
index 89bfa0820a85b7397dce020ff22a014e0d343f7f..3aa32fb1c373c484b0cbf547603bd5cf18e79551 100644 (file)
--- a/src/transport/gnunet_wlan_sender.c
+++ b/src/transport/gnunet_wlan_sender.c
@@ -30,6 +30,7 @@
 #include <netinet/in.h>
 #include <string.h>
 #include <time.h>
+#include <errno.h>
 #include "gnunet_protocols.h"
 #include "plugin_transport_wlan.h"
 
@@ -216,13 +217,18 @@ int main(int argc, char *argv[]){
        }
        else{
                /* A zero PID indicates that this is the child process */
-               dup2(commpipe[0],0);    /* Replace stdin with the in side of the pipe */
-               close(commpipe[1]);             /* Close unused side of pipe (out side) */
+               (void) close(0);
+               if (-1 == dup2(commpipe[0],0))  /* Replace stdin with the in side of the pipe */
+                 fprintf (stderr,
+                          "dup2 failed: %s\n",
+                          strerror (errno));
+               (void) close(commpipe[1]);              /* Close unused side of pipe (out side) */
                /* Replace the child fork with a new process */
-               if(execl("gnunet-transport-wlan-helper","gnunet-transport-wlan-helper", argv[1], NULL) == -1){
-                       fprintf(stderr,"Could not start gnunet-transport-wlan-helper!");
-                       exit(1);
-               }
+               if (execl("gnunet-transport-wlan-helper","gnunet-transport-wlan-helper", argv[1], NULL) == -1)
+                 {
+                   fprintf(stderr,"Could not start gnunet-transport-wlan-helper!");
+                   _exit(1);
+                 }
        }
        return 0;
 }