From: Rob Partington <rjp@...>
Date: 2001-09-30T20:17:09+09:00
Subject: [ruby-talk:21838] gethostbyname strangeness

    rjp> irb
    irb(main):001:0> require "socket"
    true
    irb(main):002:0> Socket.gethostbyname("www.rotten.com")
    SocketError: host not found
            from (irb):2:in `gethostbyname'
            from (irb):2
    irb(main):003:0> 
    rjp> host www.rotten.com
    www.rotten.com has address 216.218.248.130

The problem is this bit of ext/socket/socket.c, starting at line 1745
(taken from 1.6.5 sources, but it's the same in the stable-snapshot):

    else {
    setipaddr(host, (struct sockaddr *)&addr);
    }
    switch (addr.ss_family) {
    case AF_INET:
      {
    struct sockaddr_in *sin;
    sin = (struct sockaddr_in *)&addr;
    h = gethostbyaddr((char *)&sin->sin_addr,
              sizeof(sin->sin_addr),
              sin->sin_family);
    break;
      }

The correct information is received in setipaddr from the getaddrinfo()
call and returned to sock_s_gethostbyname.  But then Ruby does a reverse
lookup for some reason which fails for www.rotten.com and returns nothing.

    rjp> host 216.218.248.130
    Host not found.

Socket.gethostbyname() works only if there's a reverse for the IP address
it gets from the getaddrinfo() call.

This is preventing me using Ruby instead of Perl for a project since Perl
handles this situation correctly.  Is this behaviour broken, or intentional?
The fix is fairly simple -- return the information from the getaddrinfo()
call instead of trying to reverse it into a hostent struct.

I've tried this on FreeBSD, OpenBSD/sparc, Linux and MacOS X, both 1.6.4 and
1.6.5.  The MacOS X one works fine which makes me wonder if it's a "feature" 
in that library.

Any suggestions?  If people want me to send a patch to fix this, I will.
-- 
rob partington % rjp@browser.org % http://lynx.browser.org/