Re: [jira] Updated: (HARMONY-73) java.net.InetAddress.getLocalHost() returns wrong host name for loopback address

[Geir Magnusson Jr]

isn't "localhost" actually something in the local hosts file?  Don't you 
want to look this up?

Paulex Yang (JIRA) wrote:
     [ http://issues.apache.org/jira/browse/HARMONY-73?page=all ]
Paulex Yang updated HARMONY-73:
-------------------------------

    Attachment: InetAddress.patch

A suggested modification is to add these two lines before Ln. 296 of java.net.InetAddress, 

if(this == LOOPBACK){
     return "localhost";
}

So that the getHostName() will return "localhost" instead of "127.0.0.1".

The patch is attached. 

 java.net.InetAddress.getLocalHost() returns wrong host name for loopback 
address
---------------------------------------------------------------------------------

         Key: HARMONY-73
         URL: http://issues.apache.org/jira/browse/HARMONY-73
     Project: Harmony
        Type: Bug
  Components: Classlib
    Reporter: Svetlana Samoilenko
    Priority: Minor
 Attachments: InetAddress.patch

J2se 1.4.2 and 5.0 specifications for java.net.InetAddress.getLocalHost() read, that if there is a security manager, its checkConnect method is called with the local host name and -1 as its arguments to see if the operation is allowed. 
If the operation is not allowed, an InetAddress representing the loopback address is returned as hostname/hostaddress (as followed from toString() specification).
The test listed below shows that the returned loopback address has wrong hostname, 
"127.0.0.1" instead of "loopback".
Inet_SecurityManager class is called twice and therefore host name is 
substituted with hostaddress address.
Code to reproduce: 
import java.net.*; 
public class test2 { 
    public static void main(String[] args) { 
        try { 
            System.setSecurityManager(new Inet_SecurityManager());
            System.out.println("Loopback address = " + 
InetAddress.getLocalHost());
        } catch (Exception e){ 
            System.out.println("Unexpected exception = " + e); 
        }; 
    } 
} 
class Inet_SecurityManager extends SecurityManager { 
    public void checkConnect(String host, int port) { 
        super.checkConnect(host,port); 
        throw new SecurityException();
    }
}
Steps to Reproduce: 
1. Build Harmony (check-out on 2006-01-30) j2se subset as described in README.txt. 
2. Compile test2.java using BEA 1.4 javac 
javac -d . test2.java 
3. Run java using compatible VM (J9) 
java -showversion test2 
Output: 
C:\tmp>C:\jrockit-j2sdk1.4.2_04\bin\java.exe -showversion test2 
java version "1.4.2_04" 
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_04-b05) 
BEA WebLogic JRockit(TM) 1.4.2_04 JVM (build ari-31788-20040616-1132-win-ia32, Native Threads, GC strategy: parallel) 
Inet_SecurityManager :host= nswssamoil1
Inet_SecurityManager :port= -1
Loopback address = localhost/127.0.0.1
C:\tmp>C:\harmony\trunk\deploy\jre\bin\java -showversion test2 
(c) Copyright 1991, 2005 The Apache Software Foundation or its licensors, as applicable. 
Inet_SecurityManager :host= nswssamoil1
Inet_SecurityManager :port= -1
Inet_SecurityManager :host= localhost
Inet_SecurityManager :port= -1
Loopback address = 127.0.0.1/127.0.0.1
Suggested junit test case:
------------------------ InetAddressTest.java ------------------------------------------------- 
import java.net.*; 
import junit.framework.*; 
public class InetAddressTest extends TestCase { 
    public static void main(String[] args) { 
        junit.textui.TestRunner.run(InetAddress.class); 
    } 
    public void test_getLocalHost() { 
        try{            
            System.setSecurityManager(new Inet_SecurityManager()); 
            String hostname=InetAddress.getLocalHost().getHostName();           
            assertEquals("localhost", hostname);
        } catch (Exception e){ 
            fail("Unexpected exception = " + e); 
        };           
   } 
}
class Inet_SecurityManager extends SecurityManager { 
    public void checkConnect(String host, int port) { 
        super.checkConnect(host,port); 
        throw new SecurityException();
    }
}