/** Lists key table name and entries in it. */
 void listKt() {
   int version;
   String principal;
   // System.out.println("Keytab name: " + admin.getKeyTabName());
   System.out.println("Keytab name: " + table.tabName());
   // KeyTabEntry[] entries = admin.getEntries();
   KeyTabEntry[] entries = table.getEntries();
   if ((entries != null) && (entries.length > 0)) {
     System.out.println("KVNO    Principal");
     for (int i = 0; i < entries.length; i++) {
       version = entries[i].getKey().getKeyVersionNumber().intValue();
       principal = entries[i].getService().toString();
       if (i == 0) {
         StringBuffer separator = new StringBuffer();
         for (int j = 0; j < 9 + principal.length(); j++) {
           separator.append("-");
         }
         System.out.println(separator.toString());
       }
       System.out.println("  " + version + "     " + principal);
     }
   } else {
     System.out.println("0 entry.");
   }
 }
 /**
  * The main program that can be invoked at command line. <br>
  * Usage: ktab <options> <br>
  * available options to Ktab:
  *
  * <ul>
  *   <li><b>-l</b> list the keytab name and entries
  *   <li><b>-a</b> &lt;<i>principal name</i>&gt; (&lt;<i>password</i>&gt;) add an entry to the
  *       keytab. The entry is added only to the keytab. No changes are made to the Kerberos
  *       database.
  *   <li><b>-d</b> &lt;<i>principal name</i>&gt; delete an entry from the keytab The entry is
  *       deleted only from the keytab. No changes are made to the Kerberos database.
  *   <li><b>-k</b> &lt;<i>keytab name</i> &gt; specify keytab name and path with prefix FILE:
  *   <li><b>-help</b> display instructions.
  */
 public static void main(String[] args) {
   Ktab ktab = new Ktab();
   if ((args.length == 1) && (args[0].equalsIgnoreCase("-help"))) {
     ktab.printHelp();
     System.exit(0);
   } else if ((args == null) || (args.length == 0)) {
     ktab.action = 'l';
   } else {
     ktab.processArgs(args);
   }
   try {
     if (ktab.name == null) {
       //  ktab.admin = new KeyTabAdmin();    // use the default keytab.
       ktab.table = KeyTab.getInstance();
       if (ktab.table == null) {
         if (ktab.action == 'a') {
           ktab.table = KeyTab.create();
         } else {
           System.out.println("No default key table exists.");
           System.exit(-1);
         }
       }
     } else {
       if ((ktab.action != 'a') && !(new File(ktab.name)).exists()) {
         System.out.println("Key table " + ktab.name + " does not exist.");
         System.exit(-1);
       } else {
         ktab.table = KeyTab.getInstance(ktab.name);
       }
       if (ktab.table == null) {
         ktab.table = KeyTab.create(ktab.name);
       }
     }
   } catch (RealmException e) {
     System.err.println("Error loading key table.");
     System.exit(-1);
   } catch (IOException e) {
     System.err.println("Error loading key table.");
     System.exit(-1);
   }
   switch (ktab.action) {
     case 'l':
       ktab.listKt();
       break;
     case 'a':
       ktab.addEntry();
       break;
     case 'd':
       ktab.deleteEntry();
       break;
     default:
       ktab.printHelp();
       System.exit(-1);
   }
 }
  /** Deletes an entry from the key table. */
  void deleteEntry() {
    PrincipalName pname = null;
    try {
      pname = new PrincipalName(principal);
      if (pname.getRealm() == null) {
        pname.setRealm(Config.getInstance().getDefaultRealm());
      }
      String answer;
      BufferedReader cis = new BufferedReader(new InputStreamReader(System.in));
      System.out.print(
          "Are you sure you want to "
              + " delete service key for "
              + pname.toString()
              + " in "
              + table.tabName()
              + "?(Y/N) :");

      System.out.flush();
      answer = cis.readLine();
      if (answer.equalsIgnoreCase("Y") || answer.equalsIgnoreCase("Yes")) ;
      else {
        // no error, the user did not want to delete the entry
        System.exit(0);
      }

    } catch (KrbException e) {
      System.err.println("Error occured while deleting the entry. " + "Deletion failed.");
      e.printStackTrace();
      System.exit(-1);
    } catch (IOException e) {
      System.err.println("Error occured while deleting the entry. " + " Deletion failed.");
      e.printStackTrace();
      System.exit(-1);
    }
    // admin.deleteEntry(pname);
    table.deleteEntry(pname);

    try {
      table.save();
    } catch (IOException e) {
      System.err.println("Error occurs while saving the keytab." + "Deletion fails.");
      e.printStackTrace();
      System.exit(-1);
    }
    System.out.println("Done!");
  }
  /**
   * Adds a service key to key table. If the specified key table does not exist, the program will
   * automatically generate a new key table.
   */
  void addEntry() {
    PrincipalName pname = null;
    try {
      pname = new PrincipalName(principal);
      if (pname.getRealm() == null) {
        pname.setRealm(Config.getInstance().getDefaultRealm());
      }
    } catch (KrbException e) {
      System.err.println("Failed to add " + principal + " to keytab.");
      e.printStackTrace();
      System.exit(-1);
    }
    if (password == null) {
      try {
        BufferedReader cis = new BufferedReader(new InputStreamReader(System.in));
        System.out.print("Password for " + pname.toString() + ":");
        System.out.flush();
        password = new StringBuffer().append(cis.readLine());
      } catch (IOException e) {
        System.err.println("Failed to read the password.");
        e.printStackTrace();
        System.exit(-1);
      }
    }
    try {
      // admin.addEntry(pname, password);
      table.addEntry(pname, password);
      // admin.save();
      table.save();
      System.out.println("Done!");
      System.out.println("Service key for " + principal + " is saved in " + table.tabName());

    } catch (KrbCryptoException e) {
      System.err.println("Failed to add " + principal + " to keytab.");
      e.printStackTrace();
      System.exit(-1);
    } catch (IOException e) {
      System.err.println("Failed to save new entry.");
      e.printStackTrace();
      System.exit(-1);
    }
  }