This may be a weird question, maybe: is there any way to persuade s6-svscan (as pid 1) to restart _without_ doing a full hardware reboot? The use case I have in mind is: starting from a regular running system, I want to create a small "recovery" system in a ramdisk and switch to it with pivot_root so that the real root filesystem can be unmounted and manipulated. (This is instead of "just" doing a full reboot into an initramfs: the device has limited storage space and keeping a couple of MB around permanently just for "maintenance mode" doesn't seem like a great use of it)
I was thinking I could use the .svscan/finish script to check for the existence of the "maintenance mode" ramfs, remount it onto / and then `exec /bin/init` as its last action, though it seems a bit cheesy to have a file called `finish` that actually sometimes performs `single-user-mode` instead. Would that work? Perhaps a more general use case for re-execing pid 1 would be after OS upgrades as an alternative to rebooting - though other than wanting to preserve uptime for bragging rights I can't see any real advantage... Any thoughts? Daniel