Simple, reliable test case for name resolution problem

[Alfred Perlstein]

* Nick Johnson <freebsd at spatula.net> [071029 18:31] wrote:
> The problem is in the number of open file descriptors.  Once it crosses 
> 1024, name resolution breaks.  This is showing up in Tomcat 6, because 
> Tomcat 6 is leaking descriptors like a sieve.
> 
> Here's a simple test case that demonstrates the problem.  On my FreeBSD 
> 6.2 host it bombs every time.  On a Linux host, it throws an IOException 
> opening files (too many open files).  On a Windows box it completes 
> normally.
> 
> My uname and java -version, just for completeness:
> FreeBSD turing.morons.org 6.2-STABLE FreeBSD 6.2-STABLE #0: Sun Jan 21 16:53:54 PST 2007     
> java version "1.5.0_13-p7"
> Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_13-p7-root_26_oct_2007_14_03)
> 
> The same thing happens with the Diablo JDK.
> 
> Here's the code.  Save it as Test.java; javac Test.java; java Test
> 
> import java.net.*;
> import java.util.*;
> import java.io.*;
> 
> public class Test {
>         public static void main(String[] args) throws Exception {
> 
>                 ArrayList files = new ArrayList(1024);
> 
>                 System.out.println("Opening lots of files");
>                 for(int i=0; i < 1024; i++) {
>                         files.add(new FileInputStream("/dev/null"));
>                 }
> 
>                 System.out.println("Trying to resolve freebsd.org");
>                 InetAddress.getByName("freebsd.org");   // throws exception!
> 
>         }
> }
> 
Please try attached patch from cvs:

jhb         2007-03-12 19:51:57 UTC

  FreeBSD src repository

  Modified files:        (Branch: RELENG_6)
    lib/libc/resolv      res_send.c 
  Log:
  MFC: Don't reject file descriptors higher than FD_SETSIZE when using
  kevent(2).
  
  Revision  Changes    Path
  1.2.2.5   +5 -7      src/lib/libc/resolv/res_send.c