Re: [libvirt] Strange periodic failures of the commandtest case
On Mon, Feb 14, 2011 at 12:32:18PM +0000, Daniel P. Berrange wrote:
I'm getting periodic failures of the 'commandtest' case
where the diff
is
> DAEMON:no
--
< DAEMON:yes
For test cases 'test3' through to 'test15', except 'test'4. Tests
1,
2, 4, 16, 17, 18 are all unaffected. I can never reproduce it when
I run just that one test case manually, but the automated builds
I'm doing hit it > 50% of the time so it is clearly some kind of race
condition. The line of code that's getting confused is this
fprintf(log, "DAEMON:%s\n", getpgrp() == getsid(0) ? "yes" :
"no");
but I'm not clear how this can be going wrong. Ideas ?
Hmm, this seems to occur when you run the build under cron. Under an
interactive shell getpgrp() != getsid() by default. Under non-interactive
shell, then getpgrp() == getsid() even if we didn't ask to daemonize.
So this approach to detecting whether we're daemonized isn't reliable.
Perhaps the 'commandtest' program itself needs to call setsid()+setpgid()
before running the child processes ?
Daniel
--
|: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org -o- http://virt-manager.org :|
|: http://autobuild.org -o- http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|