Revamp detach code to ensure stdin, stdout, stderr get closed.

diff --git a/libraries/liblutil/detach.c b/libraries/liblutil/detach.c
index 90cb984118f3b90d1bf04addcb5af1eb98330b37..c3081ef1f679195b061b28f288c8b1ebf3d5ba2f 100644 (file)
--- a/libraries/liblutil/detach.c
+++ b/libraries/liblutil/detach.c
@@ -72,21 +72,35 @@ lutil_detach( int debug, int do_close )
                        break;
                }
 
-               if ( do_close )
-                       for ( i = 3; i < nbits; i++ )
+               if ( do_close ) {
+                       if ( (sd = open( "/dev/null", O_RDWR )) != -1 ) {
+                               perror("/dev/null");
+                       }
+
+                       for ( i = 0; i < nbits; i++ ) {
+                               if( i == sd ) continue;
+
                                close( i );
 
-               (void) chdir( "/" );
+                               if( i == STDIN_FILENO ||
+                                       i == STDOUT_FILENO ||
+                                       i == STDERR_FILENO )
+                               {
+                                       /* attach /dev/null */
+                                       dup2( sd, i );
+                               }
+                       }
 
-               if ( (sd = open( "/dev/null", O_RDWR )) == -1 ) {
-                       perror( "/dev/null" );
-                       exit( EXIT_FAILURE );
+                       if( sd != STDIN_FILENO &&
+                               sd != STDOUT_FILENO && 
+                               sd != STDERR_FILENO )
+                       {
+                               /* unless stdin, stdout, or stderr, close /dev/null */
+                               close( sd );
+                       }
                }
-               for ( i = 0;  i < 3;  i++ )
-                       if ( sd != i )
-                               (void) dup2( sd, i );
-               if ( sd > 2 )
-                       close( sd );
+
+               (void) chdir( "/" );
 
 #ifdef HAVE_SETSID
                (void) setsid();