Need support for factory reset (needed by settings)

[Sebastien Bacher]

The system settings design has an UI that includes a factory reset option:
https://wiki.ubuntu.com/SystemSettings#A.2BIBw-Reset_Phone.2BIB0-

It would be nice if the system image service could provide that option

(stgraber said "right, factory reset is basically a two lines file to dump in /cache/recovery/ubuntu_command, then call reboot -f recovery")

[Barry Warsaw (barry)]

<stgraber> barry: actually, just one: format data

[Stéphane Graber (stgraber)]

Writing "format data" to /cache/recovery/ubuntu_command and rebooting to recovery will do the trick. The upgrader will wipe the data partition and reboot without any user data.

[Matt Fischer (mfisch)]

The implementation here needs to leave the OEM customization area alone. We may have a separate dconf database hosted there.

[Barry Warsaw (barry)]

Stephane, can you verify whether 'format data' will leave the OEM area alone as Matt requests?

[Barry Warsaw (barry)]

I can easily add this to s-i 2.3, but I'd like confirmation on whether `format data` will leave the OEM area alone.

[Stéphane Graber (stgraber)]

OEM customization is in /custom which is on the read-only image and so isn't flushed when wiping the userdata partition.

[Barry Warsaw (barry)]

Thanks stgraber. Okay, so I think it would be easy to add a command line switch and a *new* D-Bus API for factory reset. The latter shouldn't have any backward compatibility constraints, and I'll document the API on the wiki, which will probably just be:

FactoryReset()