Fix merge error.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1598873 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java

@@ -231,6 +231,9 @@ public static InetSocketAddress createSocketAddr(String target) {
   private boolean checkDiskErrorFlag = false;
   private Object checkDiskErrorMutex = new Object();
   private long lastDiskErrorCheck;
+  private String supergroup;
+  private boolean isPermissionEnabled;
+  private String dnUserName = null;
 
   /**
    * Create the DataNode given a configuration, an array of dataDirs,
@@ -252,6 +255,11 @@ public static InetSocketAddress createSocketAddr(String target) {
     this.getHdfsBlockLocationsEnabled = conf.getBoolean(
         DFSConfigKeys.DFS_HDFS_BLOCKS_METADATA_ENABLED, 
         DFSConfigKeys.DFS_HDFS_BLOCKS_METADATA_ENABLED_DEFAULT);
+    this.supergroup = conf.get(DFSConfigKeys.DFS_PERMISSIONS_SUPERUSERGROUP_KEY,
+        DFSConfigKeys.DFS_PERMISSIONS_SUPERUSERGROUP_DEFAULT);
+    this.isPermissionEnabled = conf.getBoolean(
+        DFSConfigKeys.DFS_PERMISSIONS_ENABLED_KEY,
+        DFSConfigKeys.DFS_PERMISSIONS_ENABLED_DEFAULT);
 
     confVersion = "core-" +
         conf.get("hadoop.common.configuration.version", "UNSPECIFIED") +
@@ -433,6 +441,33 @@ private void initIpcServer(Configuration conf) throws IOException {
     }
   }
 
+  /** Check whether the current user is in the superuser group. */
+  private void checkSuperuserPrivilege() throws IOException, AccessControlException {
+    if (!isPermissionEnabled) {
+      return;
+    }
+    // Try to get the ugi in the RPC call.
+    UserGroupInformation callerUgi = ipcServer.getRemoteUser();
+    if (callerUgi == null) {
+      // This is not from RPC.
+      callerUgi = UserGroupInformation.getCurrentUser();
+    }
+
+    // Is this by the DN user itself?
+    assert dnUserName != null;
+    if (callerUgi.getShortUserName().equals(dnUserName)) {
+      return;
+    }
+
+    // Is the user a member of the super group?
+    List<String> groups = Arrays.asList(callerUgi.getGroupNames());
+    if (groups.contains(supergroup)) {
+      return;
+    }
+    // Not a superuser.
+    throw new AccessControlException();
+  }
+  
 /**
  * Initialize the datanode's periodic scanners:
  *     {@link DataBlockScanner}
@@ -735,6 +770,11 @@ void startDataNode(Configuration conf,
   
     // BlockPoolTokenSecretManager is required to create ipc server.
     this.blockPoolTokenSecretManager = new BlockPoolTokenSecretManager();
+
+    // Login is done by now. Set the DN user name.
+    dnUserName = UserGroupInformation.getCurrentUser().getShortUserName();
+    LOG.info("dnUserName = " + dnUserName);
+    LOG.info("supergroup = " + supergroup);
     initIpcServer(conf);
 
     metrics = DataNodeMetrics.create(conf, getDisplayName());
@@ -2414,6 +2454,7 @@ public void refreshNamenodes(Configuration conf) throws IOException {
 
   @Override // ClientDatanodeProtocol
   public void refreshNamenodes() throws IOException {
+    checkSuperuserPrivilege();
     conf = new Configuration();
     refreshNamenodes(conf);
   }
@@ -2421,6 +2462,7 @@ public void refreshNamenodes() throws IOException {
   @Override // ClientDatanodeProtocol
   public void deleteBlockPool(String blockPoolId, boolean force)
       throws IOException {
+    checkSuperuserPrivilege();
     LOG.info("deleteBlockPool command received for block pool " + blockPoolId
         + ", force=" + force);
     if (blockPoolManager.get(blockPoolId) != null) {
@@ -2436,6 +2478,7 @@ public void deleteBlockPool(String blockPoolId, boolean force)
 
   @Override // ClientDatanodeProtocol
   public synchronized void shutdownDatanode(boolean forUpgrade) throws IOException {
+    checkSuperuserPrivilege();
     LOG.info("shutdownDatanode command received (upgrade=" + forUpgrade +
         "). Shutting down Datanode...");