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

[Stuart Lynne]

In article <[e-mail]>,
Amit D Chaudhary <[e-mail]> 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 <[e-mail]>       www.fireplug.net        604-461-7532