HDFS-3907. Allow multiple users for local block readers. Contributed by Eli Collins

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1383053 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -265,6 +265,8 @@ Release 2.0.2-alpha - 2012-09-07
 
     HDFS-3888. Clean up BlockPlacementPolicyDefault.  (Jing Zhao via szetszwo)
 
+    HDFS-3907. Allow multiple users for local block readers. (eli)
+
   OPTIMIZATIONS
 
     HDFS-2982. Startup performance suffers when there are many edit log

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

@@ -281,7 +281,7 @@ public class DataNode extends Configured
   private AbstractList<File> dataDirs;
   private Configuration conf;
 
-  private final String userWithLocalPathAccess;
+  private final List<String> usersWithLocalPathAccess;
   private boolean connectToDnViaHostname;
   ReadaheadPool readaheadPool;
   private final boolean getHdfsBlockLocationsEnabled;
@@ -304,8 +304,8 @@ public class DataNode extends Configured
            final SecureResources resources) throws IOException {
     super(conf);
 
-    this.userWithLocalPathAccess =
+    this.usersWithLocalPathAccess = Arrays.asList(
-        conf.get(DFSConfigKeys.DFS_BLOCK_LOCAL_PATH_ACCESS_USER_KEY);
+        conf.getTrimmedStrings(DFSConfigKeys.DFS_BLOCK_LOCAL_PATH_ACCESS_USER_KEY));
     this.connectToDnViaHostname = conf.getBoolean(
         DFSConfigKeys.DFS_DATANODE_USE_DN_HOSTNAME,
         DFSConfigKeys.DFS_DATANODE_USE_DN_HOSTNAME_DEFAULT);
@@ -1012,7 +1012,7 @@ public class DataNode extends Configured
   private void checkBlockLocalPathAccess() throws IOException {
     checkKerberosAuthMethod("getBlockLocalPathInfo()");
     String currentUser = UserGroupInformation.getCurrentUser().getShortUserName();
-    if (!currentUser.equals(this.userWithLocalPathAccess)) {
+    if (!usersWithLocalPathAccess.contains(currentUser)) {
       throw new AccessControlException(
           "Can't continue with getBlockLocalPathInfo() "
               + "authorization. The user " + currentUser

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestShortCircuitLocalRead.java

@@ -224,7 +224,8 @@ public class TestShortCircuitLocalRead {
   @Test
   public void testGetBlockLocalPathInfo() throws IOException, InterruptedException {
     final Configuration conf = new Configuration();
-    conf.set(DFSConfigKeys.DFS_BLOCK_LOCAL_PATH_ACCESS_USER_KEY, "alloweduser");
+    conf.set(DFSConfigKeys.DFS_BLOCK_LOCAL_PATH_ACCESS_USER_KEY,
+        "alloweduser1,alloweduser2");
     MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf).numDataNodes(1)
         .format(true).build();
     cluster.waitActive();
@@ -232,8 +233,10 @@ public class TestShortCircuitLocalRead {
     FileSystem fs = cluster.getFileSystem();
     try {
       DFSTestUtil.createFile(fs, new Path("/tmp/x"), 16, (short) 1, 23);
-      UserGroupInformation aUgi = UserGroupInformation
+      UserGroupInformation aUgi1 =
-          .createRemoteUser("alloweduser");
+          UserGroupInformation.createRemoteUser("alloweduser1");
+      UserGroupInformation aUgi2 =
+          UserGroupInformation.createRemoteUser("alloweduser2");
       LocatedBlocks lb = cluster.getNameNode().getRpcServer()
           .getBlockLocations("/tmp/x", 0, 16);
       // Create a new block object, because the block inside LocatedBlock at
@@ -241,7 +244,7 @@ public class TestShortCircuitLocalRead {
       ExtendedBlock blk = new ExtendedBlock(lb.get(0).getBlock());
       Token<BlockTokenIdentifier> token = lb.get(0).getBlockToken();
       final DatanodeInfo dnInfo = lb.get(0).getLocations()[0];
-      ClientDatanodeProtocol proxy = aUgi
+      ClientDatanodeProtocol proxy = aUgi1
           .doAs(new PrivilegedExceptionAction<ClientDatanodeProtocol>() {
             @Override
             public ClientDatanodeProtocol run() throws Exception {
@@ -256,7 +259,23 @@ public class TestShortCircuitLocalRead {
           DataNodeTestUtils.getFSDataset(dn).getBlockLocalPathInfo(blk).getBlockPath(),
           blpi.getBlockPath());
 
-      // Now try with a not allowed user.
+      // Try with the other allowed user
+      proxy = aUgi2
+          .doAs(new PrivilegedExceptionAction<ClientDatanodeProtocol>() {
+            @Override
+            public ClientDatanodeProtocol run() throws Exception {
+              return DFSUtil.createClientDatanodeProtocolProxy(dnInfo, conf,
+                  60000, false);
+            }
+          });
+
+      // This should succeed as well
+      blpi = proxy.getBlockLocalPathInfo(blk, token);
+      Assert.assertEquals(
+          DataNodeTestUtils.getFSDataset(dn).getBlockLocalPathInfo(blk).getBlockPath(),
+          blpi.getBlockPath());
+
+      // Now try with a disallowed user
       UserGroupInformation bUgi = UserGroupInformation
           .createRemoteUser("notalloweduser");
       proxy = bUgi