On Fri, May 30, 2008 at 11:40:00AM -0700, Dave Leskovec wrote:
Daniel P. Berrange wrote:
On Fri, May 30, 2008 at 02:28:46AM -0400, Daniel Veillard wrote:
On Thu, May 29, 2008 at 03:20:15PM -0700, Dave Leskovec wrote:
+ if (ESRCH == errno) { + rc = 0; + DEBUG("pid %d no longer exists", def->id); + goto done; + } + + lxcError(NULL, NULL, VIR_ERR_INTERNAL_ERROR, + _("error checking container process: %d %s"), + def->id, strerror(errno)); + goto done; + } The problem though is that by doing just a passive test for the PID it feels like there is a possible race if the process counter rolled over and another process with the same PID got create in the meantime. i have the feeling that a test based on the state of the file descriptors used to communicate with the container would be more reliable. Basically if the container disapear, then the pipe should get in a half-closed state, detecting the change at that level sounds like it would be more reliable, don't you think so ?
Yes, after checking the PID still exists, it needs to validate /proc/$PID/exe to verify it points to the binary we expect it to.
Hmmm.... Worked with this a bit and I don't think we can reliably know what to expect /proc/$PID/exe to point to. For scripts, /proc/$PID/exe seems to point the shell. Also, if the container does an exec, /proc/$PID/exe points to whatever it exec'd rather than the init program.
Well the path won't change once launched, so why not store the original value of /proc/$PID/exe in the /var/lib/libivrt/lxc/NAME.pid file too, so you can read it back out later & validate. Dan. -- |: Red Hat, Engineering, Boston -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|