On Mon, Aug 21, 2017 at 8:38 PM, Ben Hutchings <b...@decadent.org.uk> wrote:
> On Mon, 2017-08-21 at 19:40 +0200, Denys Vlasenko wrote:
>> > On Mon, Aug 14, 2017 at 5:12 PM, Ben Hutchings <b...@decadent.org.uk>
>> > wrote:
>> > On Mon, 2017-08-14 at 16:42 +0200, Denys Vlasenko wrote:
>> > > > > run-init
>> > >
>> > > This tool is doing this:
>> >
>> > [...]
>> > > There is the "switch_root" tool in util-linux which does the
>> > > crucial part of this functionality - deleting / remounting / chrooting.
>> > > It is in bbox too.
>> >
>> > initramfs-tools used to use switch_root if possible, but it didn't
>> > support the -d (drop capabilities) option. Later on we needed
>> > validation of the init filename to support symlinks (e.g. /sbin/init ->
>> > /lib/systemd/systemd), so I added and used the -n (dry run) option to
>> > run-init. busybox would need to support both of these.
>>
>> I added run-init to busybox just now, but I don't see -n option in
>> klibc-2.0.4 source. Can you point me to the source code with -n?
>
> It's not upstream yet, but in a Debian patch:
> https://sources.debian.net/src/klibc/2.0.4-9/debian/patches/run-init-add-dry-run-mode.patch/
Done:
$ ./busybox run-init
BusyBox v1.28.0.git (2017-08-21 18:55:09 CEST) multi-call binary.
Usage: run-init [-d CAP,CAP...] [-n] [-c CONSOLE_DEV] NEW_ROOT NEW_INIT [ARGS]
Free initramfs and switch to another root fs:
chroot to NEW_ROOT, delete all in /, move NEW_ROOT to /,
execute NEW_INIT. PID must be 1. NEW_ROOT must be a mountpoint.
-c DEV Reopen stdio to DEV after switch
-d CAPS Drop capabilities
-n Dry run
