From cfd8a2174afb1140b5042d913782b24615f32bfe Mon Sep 17 00:00:00 2001
From: Allen Wittenauer <aw@apache.org>
Date: Wed, 11 Feb 2015 07:40:39 -0800
Subject: [PATCH] HADOOP-11554. Expose HadoopKerberosName as a hadoop
 subcommand (aw)

---
 hadoop-common-project/hadoop-common/CHANGES.txt        |  2 ++
 .../hadoop-common/src/main/bin/hadoop                  |  4 ++++
 .../hadoop-common/src/main/bin/hadoop.cmd              |  6 +++++-
 .../hadoop-common/src/site/markdown/CommandsManual.md  | 10 ++++++++++
 .../hadoop-common/src/site/markdown/SecureMode.md      |  2 ++
 5 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/hadoop-common-project/hadoop-common/CHANGES.txt b/hadoop-common-project/hadoop-common/CHANGES.txt
index 1536e442594..e2f176170d2 100644
--- a/hadoop-common-project/hadoop-common/CHANGES.txt
+++ b/hadoop-common-project/hadoop-common/CHANGES.txt
@@ -27,6 +27,8 @@ Trunk (Unreleased)
     HADOOP-8934. Shell command ls should include sort options (Jonathan Allen
     via aw)
 
+    HADOOP-11554. Expose HadoopKerberosName as a hadoop subcommand (aw)
+
   IMPROVEMENTS
 
     HADOOP-8017. Configure hadoop-main pom to get rid of M2E plugin execution
diff --git a/hadoop-common-project/hadoop-common/src/main/bin/hadoop b/hadoop-common-project/hadoop-common/src/main/bin/hadoop
index d689bdad14b..42e4e83b364 100755
--- a/hadoop-common-project/hadoop-common/src/main/bin/hadoop
+++ b/hadoop-common-project/hadoop-common/src/main/bin/hadoop
@@ -38,6 +38,7 @@ function hadoop_usage()
   echo "                       note: please use \"yarn jar\" to launch"
   echo "                             YARN applications, not this command."
   echo "  jnipath              prints the java.library.path"
+  echo "  kerbname             show auth_to_local principal conversion"
   echo "  key                  manage keys via the KeyProvider"
   echo "  trace                view and modify Hadoop tracing settings"
   echo "  version              print the version"
@@ -156,6 +157,9 @@ case ${COMMAND} in
     echo "${JAVA_LIBRARY_PATH}"
     exit 0
   ;;
+  kerbname)
+    CLASS=org.apache.hadoop.security.HadoopKerberosName
+  ;;
   key)
     CLASS=org.apache.hadoop.crypto.key.KeyShell
   ;;
diff --git a/hadoop-common-project/hadoop-common/src/main/bin/hadoop.cmd b/hadoop-common-project/hadoop-common/src/main/bin/hadoop.cmd
index f612ace7cca..c600fd12665 100644
--- a/hadoop-common-project/hadoop-common/src/main/bin/hadoop.cmd
+++ b/hadoop-common-project/hadoop-common/src/main/bin/hadoop.cmd
@@ -146,7 +146,7 @@ call :updatepath %HADOOP_BIN_PATH%
     )
   )
   
-  set corecommands=fs version jar checknative distcp daemonlog archive classpath credential key
+  set corecommands=fs version jar checknative distcp daemonlog archive classpath credential kerbname key
   for %%i in ( %corecommands% ) do (
     if %hadoop-command% == %%i set corecommand=true  
   )
@@ -215,6 +215,10 @@ call :updatepath %HADOOP_BIN_PATH%
   set CLASS=org.apache.hadoop.security.alias.CredentialShell
   goto :eof
 
+:kerbname
+  set CLASS=org.apache.hadoop.security.HadoopKerberosName
+  goto :eof
+
 :key
   set CLASS=org.apache.hadoop.crypto.key.KeyShell
   goto :eof
diff --git a/hadoop-common-project/hadoop-common/src/site/markdown/CommandsManual.md b/hadoop-common-project/hadoop-common/src/site/markdown/CommandsManual.md
index b9c92c42189..f0c0367c12b 100644
--- a/hadoop-common-project/hadoop-common/src/site/markdown/CommandsManual.md
+++ b/hadoop-common-project/hadoop-common/src/site/markdown/CommandsManual.md
@@ -27,6 +27,7 @@
         * [fs](#fs)
         * [jar](#jar)
         * [jnipath](#jnipath)
+        * [kerbname](#kerbname)
         * [key](#key)
         * [trace](#trace)
         * [version](#version)
@@ -175,6 +176,15 @@ Usage: `hadoop jnipath`
 
 Print the computed java.library.path.
 
+### `kerbname`
+
+    Usage: <<<hadoop kerbname principal>>>
+
+    Convert the named principal via the auth_to_local rules to the Hadoop
+    user name.
+
+    Example: <<<hadoop kerbname user@EXAMPLE.COM>>>
+
 ### `key`
 
 Manage keys via the KeyProvider.
diff --git a/hadoop-common-project/hadoop-common/src/site/markdown/SecureMode.md b/hadoop-common-project/hadoop-common/src/site/markdown/SecureMode.md
index ae057bc2cd3..f0e1f1fbe9e 100644
--- a/hadoop-common-project/hadoop-common/src/site/markdown/SecureMode.md
+++ b/hadoop-common-project/hadoop-common/src/site/markdown/SecureMode.md
@@ -162,6 +162,8 @@ Hadoop maps Kerberos principal to OS user account using the rule specified by `h
 
 By default, it picks the first component of principal name as a user name if the realms matches to the `default_realm` (usually defined in /etc/krb5.conf). For example, `host/full.qualified.domain.name@REALM.TLD` is mapped to `host` by default rule.
 
+Custom rules can be tested using the <<<hadoop kerbname>>> command.  This command allows one to specify a principal and apply Hadoop's current auth_to_local ruleset.  The output will be what identity Hadoop will use for its usage.
+
 ### Mapping from user to group
 
 Though files on HDFS are associated to owner and group, Hadoop does not have the definition of group by itself. Mapping from user to group is done by OS or LDAP.