From: Mark Wooding <mdw@distorted.org.uk>
Date: Mon, 18 Jan 2010 14:45:04 +0000 (+0000)
Subject: dot/bash_profile (__mdw_addto) SECURITY: Only set var if it changed.
X-Git-Url: https://git.distorted.org.uk/~mdw/profile/commitdiff_plain/85d3810bff9add23ef3bd9e30b02821b3e6b9279

dot/bash_profile (__mdw_addto) SECURITY: Only set var if it changed.

If this isn't done, we end up with empty variables where previously they
were unset.  This is especially bad for PYTHONPATH, which will pick
`site.py' out of the current directory.
---

diff --git a/dot/bash_profile b/dot/bash_profile
index a6015e9..abd3463 100644
--- a/dot/bash_profile
+++ b/dot/bash_profile
@@ -19,7 +19,7 @@ cd $HOME
 # --- Add elements to a path string ---
 
 __mdw_addto () {
-  local var=$1 val dir=$2 new=""
+  local var=$1 val dir=$2 new="" change=nil
   eval "val=\$$var"
   shift 2
   for i in "$@"; do
@@ -27,7 +27,7 @@ __mdw_addto () {
     [ -d $i ] || continue
     case "X$val" in
       X)
-	val=$i
+	val=$i change=t
 	continue
 	;;
       X$i)
@@ -43,13 +43,13 @@ __mdw_addto () {
 	val=${val%:$i}
 	;;
     esac
-    new=$new:$i
+    new=$new:$i change=t
   done
   case $dir in
     l) val=${new#:}:$val;;
     r) val=$val$new;;
   esac
-  export $var=$val
+  case $change in t) export $var=$val ;; esac
 }
 
 # --- Set the path variable ---