Re: [PATCH] chroot= as a new kernel parameter

Hi!

hi *real* hackers,

:-).

it is a my first post to lkml and I hope that you will have not been
ignored me if I have done some incorrect thing.

In the short this patch has added a new chroot= kernel parameter which can be used
to changing a chroot of an init process before it will has been runed.
I use that for testing variouses distroes without making a separate partition but
by copied a new root-fs to a new subdirectory on the my *base* filesystem.

Yes please. I was thinking about doing this long ago, but never got to
coding it.


diff -urp linux-2.6.24-orig/Documentation/kernel-parameters.txt linux-2.6.24/Documentation/kernel-parameters.txt
--- linux-2.6.24-orig/Documentation/kernel-parameters.txt 2008-02-25 20:53:26.000000000 -0500
+++ linux-2.6.24/Documentation/kernel-parameters.txt 2008-02-25 20:51:21.000000000 -0500
@@ -381,6 +381,8 @@ and is between 256 and 4096 characters.
Value can be changed at runtime via
/selinux/checkreqprot.

+ chroot= [KNL] call chroot() for init proccess.
+
clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
[Deprecated]
Forces specified clocksource (if available) to be used
diff -urp linux-2.6.24-orig/init/main.c linux-2.6.24/init/main.c
--- linux-2.6.24-orig/init/main.c 2008-03-01 12:58:37.000000000 -0500
+++ linux-2.6.24/init/main.c 2008-02-25 20:36:06.000000000 -0500
@@ -755,8 +755,22 @@ static void __init do_pre_smp_initcalls(
spawn_softlockup_task();
}

+static void *chroot_str;
+static int __init chroot_setup(char *str)
+{
+ chroot_str = str;
+ return 1;
+}
+__setup("chroot=", chroot_setup);
+
static void run_init_process(char *init_filename)
{
+ if(chroot_str) {

'if ('

+ if(sys_chroot(chroot_str) < 0)

here too.

+ printk("chroot=%s failed\n", chroot_str);
+ else
+ printk("chroot=%s successed\n",chroot_str);

And I do not think we want to printk in the success case.

Thanks,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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