HADOOP-15123. KDiag tries to load krb5.conf from KRB5CCNAME instead of KRB5_CONFIG.

Contributed by Vipin Rathor.

(cherry picked from commit 1ef906e29e0989aafcb35c51ad2acbb262b3c8e7)
(cherry picked from commit f61edab1d0ea08b6d752ecdfb6068103822012ec)

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/KDiag.java

@@ -81,6 +81,11 @@ public class KDiag extends Configured implements Tool, Closeable {
    * variable. This is what kinit will use by default: {@value}
    */
   public static final String KRB5_CCNAME = "KRB5CCNAME";
+  /**
+   * Location of main kerberos configuration file as passed down via an
+   * environment variable.
+   */
+  public static final String KRB5_CONFIG = "KRB5_CONFIG";
   public static final String JAVA_SECURITY_KRB5_CONF
     = "java.security.krb5.conf";
   public static final String JAVA_SECURITY_KRB5_REALM
@@ -321,14 +326,15 @@ public class KDiag extends Configured implements Tool, Closeable {
 
     title("Environment Variables");
     for (String env : new String[]{
-      HADOOP_JAAS_DEBUG,
-      KRB5_CCNAME,
-      HADOOP_USER_NAME,
-      HADOOP_PROXY_USER,
-      HADOOP_TOKEN_FILE_LOCATION,
-      "HADOOP_SECURE_LOG",
-      "HADOOP_OPTS",
-      "HADOOP_CLIENT_OPTS",
+        HADOOP_JAAS_DEBUG,
+        KRB5_CCNAME,
+        KRB5_CONFIG,
+        HADOOP_USER_NAME,
+        HADOOP_PROXY_USER,
+        HADOOP_TOKEN_FILE_LOCATION,
+        "HADOOP_SECURE_LOG",
+        "HADOOP_OPTS",
+        "HADOOP_CLIENT_OPTS",
     }) {
       printEnv(env);
     }
@@ -562,14 +568,14 @@ public class KDiag extends Configured implements Tool, Closeable {
         krbPath = jvmKrbPath;
       }
 
-      String krb5name = System.getenv(KRB5_CCNAME);
+      String krb5name = System.getenv(KRB5_CONFIG);
       if (krb5name != null) {
         println("Setting kerberos path from environment variable %s: \"%s\"",
-          KRB5_CCNAME, krb5name);
+            KRB5_CONFIG, krb5name);
         krbPath = krb5name;
         if (jvmKrbPath != null) {
           println("Warning - both %s and %s were set - %s takes priority",
-            JAVA_SECURITY_KRB5_CONF, KRB5_CCNAME, KRB5_CCNAME);
+              JAVA_SECURITY_KRB5_CONF, KRB5_CONFIG, KRB5_CONFIG);
         }
       }
 
@@ -919,7 +925,7 @@ public class KDiag extends Configured implements Tool, Closeable {
   private void dump(File file) throws IOException {
     try (FileInputStream in = new FileInputStream(file)) {
       for (String line : IOUtils.readLines(in)) {
-        println(line);
+        println("%s", line);
       }
     }
   }