On Sat, 2011-06-11 at 18:46 -0700, Eric W. Biederman wrote: > Greg Kurz <gkurz@xxxxxxxxxx> writes: > > > Since pid namespaces were introduced, there's a recurring demand: how one > > can correlate a pid from a child pid ns with a pid from a parent pid ns ? > > The need arises in the LXC community when one wants to send a signal from > > the host (aka. init_pid_ns context) to a container process for which one > > only knows the pid inside the container. > Eric, Thanks for your comments. > You are missing taking the sighand lock which is needed to make > task_active_pid_ns safe when called on something other than current. > Ohh... to prevent __exit_signal()->__unhash_process() to detach the pids in our back, correct ? A comment in <linux/pid_namespace.h> would be appreciated... > I really don't like the name VPid, perhaps Process Pid. There is > nothing more or less virtual about any pid, so calling any of the > virtual is not clear, and misleading. > Or 'Active Pid', since we're relying on task_active_pid_ns(). IOW the output is what the process gets when calling getpid(). > I'm not exactly certain that /proc/self/status is the right place > for this but this does seem reasonable. > Well... I didn't want to add another file and status is the easier one to patch without breaking anything. It seemed reasonable indeed. > For what it's worth if you are communicating through anything except > a pid file unix domain sockets will give you a race free to get the > pid of the process on the other end. > I'm in a pid file scenario for the moment... but this could change, so I'll give a try to the SCM_CREDENTIALS stuff. Cheers. -- Gregory Kurz gkurz@xxxxxxxxxx Software Engineer @ IBM/Meiosys http://www.ibm.com Tel +33 (0)534 638 479 Fax +33 (0)561 400 420 "Anarchy is about taking complete responsibility for yourself." Alan Moore. _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
