Re: question \ information request on init \ boot sequence when using initrd

Stuart Lynne (sl@whiskey.fireplug.net)
26 Mar 2001 20:17:11 -0800


In article <985660830.32357@whiskey.enposte.net>,
Amit D Chaudhary <amit@muppetlabs.com> wrote:
>Hi,
>
>We(my team) had some questions regarding booting from initrd and using
>/linuxrc. It will help someone(David, Werner,...) can give their
>thoughts on this.
>
>To put it in brief, since running sbin/init from /linuxrc as resulting
>in init not having PID 1 and thereby not doing some initialization as
>expected.
>
>Thereby instead of loading running /sbin/init, we just set
>/proc/sys/kernel/real-root-dev to /dev/ram0's value which then does the
>following
>runs 2 statements in init/main.c to unlock_kernel and free init memory
>and then run sbin/init.
>This results in /sbin/init running fine.
>
>Is this ok or should be modify /sbin/init to run properly inspite of PID
><> 1 or is there a 3rd way of doing this?
>
>
>mkdir initrd
>../bin/pivot_root . initrd
>
>exec sbin/chroot . sbin/init.new 3 <dev/console >dev/console 2>&1
>
>
>The above results in init running with PID != 1 and thereby skipping
>some relevant processing my default. see ps output below:
>
>Instead of the "chroot" above is changed to following
>exec sbin/chroot . sh -c 'bin/mount proc proc -t proc; echo 0x01000000 >
>proc/sys/kernel/real-root-dev'
>And linuxrc exits
>
>
>
>(none):root> ps -e
> PID TTY TIME CMD
> 1 ? 00:00:04 swapper
> 2 ? 00:00:00 keventd
> 3 ? 00:00:00 kswapd
> 4 ? 00:00:00 kreclaimd
> 5 ? 00:00:00 bdflush
> 6 ? 00:00:00 kupdate
> 7 ? 00:00:00 mtdblockd
> 8 ? 00:00:00 init
> 26 ? 00:00:00 sh
> 39 ? 00:00:00 portmap
> 50 ? 00:00:00 ypbind
> 51 ? 00:00:00 ypbind
> 84 ? 00:00:00 inetd
> 93 ? 00:00:00 syslogd
> 100 ? 00:00:00 klogd
> 119 ? 00:00:00 ps

You can run your linuxrc with:

init=/linuxrc

and then end your /linuxrc with:

exec /sbin/init

-- 
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Stuart Lynne <sl@fireplug.net>       www.fireplug.net        604-461-7532
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