Re: [Q] pivot_root and initrd

[Andreas Schwab]

[e-mail] (Kai Henningsen) writes:

|> [e-mail] (Eric)  wrote on 17.10.01 in <[e-mail]>:
|> 
|> > You are simply doing the following, I assume with success:
|> 
|> >    exec /sbin/init "$@"
|> 
|> > whereas I am doing something like the following:
|> 
|> >    exec chroot . sh -c 'umount $OLDROOT; exec -a init.new /sbin/init
|> >      $INITARGS' <dev/console >dev/console 2>&1
|> 
|> > I am mystified that the call to 'exec /sbin/init' works if you are using
|> > the standard (you mention "based on RedHat7.1" util-linux") /sbin/init
|> > proggie, and that a standard RH7.1 initscripts would not complain when
|> > the root filesystem is already mounted r/w.
|> 
|> It works because the PID is 1, of course.
|> 
|> /linuxrc (or however you call it) runs with PID=1, so when it exec's /sbin/ 
|> init, the PID is still 1.
|> 
|> OTOH, you have chroot run a shell as a child, which therefore does *not*  
|> have PID=1.

linuxrc does 'exec chroot', chroot does 'exec sh', sh does 'exec init'.
Thus init should end up with the same pid as linuxrc.

Andreas.

-- 
Andreas Schwab                                  "And now for something
[e-mail]				completely different."
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