[Toybox] watchdog: Can't call daemon() on nommu

[Rob Landley]

On 10/21/20 4:24 AM, Patrick Oppenlander wrote:
> Sure, but..
> 
> $ watchdog -F &
> 
> works on nommu

So I'm poking at a vfork() based xvdaemon() with nommu support, and the ONLY
caller of daemon() without 0,0 arguments is watchdog.

I think not closing stdin/stdout/stderr is irrelevant here (it doesn't use them
afterwards? Do you WANT it to stay attached to the tty in -F mode?), but the no
chroot("/") is my question:

Do you want to support relative DEV arguments in the watchdog command? Because
if not, I can just make xvdaemon() take no arguments and unconditionally do
both, which is what every other caller wants so far.

(The error handling is a pain, because we closed stdin/stdout/stderr so HOW do
we report errors afterwards... open /dev/tty I guess... but the other thing is
the vfork() flow control requires restarting from command_main() each time so
the caller of xvdaemon() has to be aware of this. The command restarts when it's
called, but the second call returns rather than restarting. So I have to audit
each caller while converting, and remove some of the depends on TOYBOX_FORK
annotations from the commands...)

Rob