From: Eric Schwartz <eric.schwartz@...>
Date: 2003-02-25T11:51:30+09:00
Subject: C Extension not exiting properly?

This is puzzling me mightily.  I have written a C extension to Ruby to
allow it to interact with STAF.  All of a sudden, it's starting to
cause my Ruby programs that use it to hang on exit.  The truly odd
thing is that it will sometimes work once or twice, then stop.  Here's
a simple CGI program that will exhibit the behaviour:

#!/usr/bin/ruby -w
$:.push('/home/emschwar/src/lsotest/cgi-bin')
require 'cgi'
require 'staf/STAFHandle'

cgi = CGI.new('html4');

cgi.out {
  cgi.html {
    cgi.head { cgi.title { "Testing" } }+
      cgi.body { cgi.p {"It's only a test"}}
  }
}

Notice that it does not actually use the STAFHandle class; it just
loads it.  This is apparently sufficient.

I've posted the contents of the library (it's not large, but 178 lines
is too large for USENET) to
http://people.debian.org/~emschwar/libstaf-ruby.tar.gz  if you care to
peruse it.

Here's what happens when I run the above program as a CGI

emschwar  6201  4319  1 19:25 ?        00:00:00 /usr/bin/ruby -w testing
emschwar  6205  6201  0 19:25 ?        00:00:00 [testing] <defunct>

(process 4319 is apache).

When I run it on the command-line, it runs correctly for two or three
times, and then hangs in exactly the same situation as above.  No
output is produced in that case.

Interestingly, I've even ifdef'd out Init_STAFHandle() in
STAFHandle.c, and it *still* does this.  I confess to severe
frustration here.  Any clues would be most welcome.

Another data point: attaching to the hung ruby process with gdb gives
me a stack trace that indicates ruby is trying to exit, and somehow
this extension is inhibiting it:

#0  0x40134ae2 in sigsuspend () from /lib/libc.so.6
#1  0x40362f35 in __pthread_wait_for_restart_signal () from /lib/libpthread.so.0
#2  0x40362be2 in pthread_onexit_process () from /lib/libpthread.so.0
#3  0x40136884 in exit () from /lib/libc.so.6
#4  0x4003c7d9 in ruby_stop () from /usr/lib/libruby.so.1.6
#5  0x4003c8e6 in ruby_run () from /usr/lib/libruby.so.1.6
#6  0x080485b4 in main ()
#7  0x40123a51 in __libc_start_main () from /lib/libc.so.6

I'm not (explicitly, anyhow) using pthreads, so I can only assume that
ruby is somehow doing this on my behalf.

-=Eric
-- 
Come to think of it, there are already a million monkeys on a million
typewriters, and Usenet is NOTHING like Shakespeare.
		-- Blair Houghton.