Re: [libvirt] [PATCH 1/1] lxc: handle shutdown (and detect, but mis-handle reboot)

The -mm tree has Daniel Lezcano's patch changing the handling of sys_reboot in a non-init pidns. That means that, with that support, (a) it is safe to grant CAP_SYS_BOOT to a container, and (b) it's possible to distinguish between reboot and shutdown. I've implemented partial support of this for libvirt in the patch below. If Daniel's patch is not in the running kernel, then CAP_SYS_BOOT will be dropped for the container. Otherwise, it will be kept in. When the container exits, if it was determined to be a shutdown, the container will terminate. However, I didn't know how to properly do the reboot part. The patch below shows how to detect it (and sets the static bool wantreboot to true in that case), but I didn't know quite what to do with that. It looks like the code flow between lxcControllerRun and lxcControllerMain would need to be changed a bit so that we could re-run the lxcContainerStart() without causing the monitor.serverFD (or whichever pipe sends monitor events to lxc_driver.c to trigger autodestroy) to be closed. So for now I'm sending this patch, and hoping the sorcerers on this list can hook reboot up as well, or show the best way how.