From f3035ff78d77b09eccd9e1f3881663e50ea204e4 Mon Sep 17 00:00:00 2001
From: Yumin Yuan <yumin.yuan@kitware.com>
Date: Wed, 15 Apr 2009 10:45:29 -0400
Subject: [PATCH] BUG: SystemTools::GetParentDirectory() will crash if "/" is
 passed in as argement. Valid check is added to make sure the input argment
 exists, and if "/" is passed in, empty string will be returned.

---
 Source/kwsys/SystemTools.cxx | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/Source/kwsys/SystemTools.cxx b/Source/kwsys/SystemTools.cxx
index 7c81eb08f..94b75915b 100644
--- a/Source/kwsys/SystemTools.cxx
+++ b/Source/kwsys/SystemTools.cxx
@@ -3975,12 +3975,18 @@ bool SystemTools::SetPermissions(const char* file, mode_t mode)
 
 kwsys_stl::string SystemTools::GetParentDirectory(const char* fileOrDir)
 {
-  if ( !fileOrDir || !*fileOrDir )
+  if ( !fileOrDir || !*fileOrDir || !SystemTools::FileExists(fileOrDir))
     {
     return "";
     }
   kwsys_stl::string res = fileOrDir;
   SystemTools::ConvertToUnixSlashes(res);
+  
+  // If the root "/" directory is passed in, return empty string
+  if(strcmp(res.c_str(), "/") ==0 )
+    {
+    return "";
+    }
   kwsys_stl::string::size_type cc = res.size()-1;
   if ( res[cc] == '/' )
     {