HADOOP-7089. Fix link resolution logic in hadoop-config.sh. Contributed by Eli Collins

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1058881 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -443,6 +443,8 @@ Release 0.22.0 - Unreleased
     HADOOP-7101. UserGroupInformation.getCurrentUser() fails when called from
     non-Hadoop JAAS context. (todd)
 
+    HADOOP-7089. Fix link resolution logic in hadoop-config.sh. (eli)
+
 Release 0.21.1 - Unreleased
 
   IMPROVEMENTS

bin/hadoop-config.sh

@@ -17,23 +17,12 @@
 # should not be executable directly
 # also should not be passed any arguments, since we need original $*
 
-# resolve links - $0 may be a softlink
-
+# Resolve links ($0 may be a softlink) and convert a relative path
+# to an absolute path.  NB: The -P option requires bash built-ins
+# or POSIX:2001 compliant cd and pwd.
 this="${BASH_SOURCE-$0}"
-while [ -h "$this" ]; do
-  ls=`ls -ld "$this"`
-  link=`expr "$ls" : '.*-> \(.*\)$'`
-  if expr "$link" : '.*/.*' > /dev/null; then
-    this="$link"
-  else
-    this=`dirname "$this"`/"$link"
-  fi
-done
-
-# convert relative path to absolute path
-common_bin=`dirname "$this"`
-script=`basename "$this"`
-common_bin=`cd "$common_bin"; pwd`
+common_bin=$(cd -P -- "$(dirname -- "$this")" && pwd -P)
+script="$(basename -- "$this")"
 this="$common_bin/$script"
 
 # the root of the Hadoop installation