Common wisdom to enter single user on Linux is to edit command
line and add "single". This was not possible because switch_root
was always called with empty init arguments. Collect them from
command line and pass to real init when switching root.
Signed-off-by: Andrey Borzenkov <arvidjaar@mail.ru>
for some unknown reason the emergency shell
starts with stderr closed, at first I even tought it was not working at
all, then I came up with this hack, which seems to work properly. I also
change the prompt to remind which step are we breaking to.
I am not happy about this. It shouldn't be the job of dracut to do this. The initscripts should
deal with the plain /dev/.initramfs/ifcfg/ directory accordingly. Doing this for now because
notting insists upon it. We need to clean this up after we network option passing working.
init now has the following points to inject scripts:
/cmdline/*.sh
scripts for command line parsing
/pre-udev/*.sh
scripts to run before udev is started
/pre-trigger/*.sh
scripts to run before the main udev trigger is pulled
/initqueue/*.sh
runs in parallel to the udev trigger
Udev events can add scripts here with /sbin/initqueue.
If /sbin/initqueue is called with the "--onetime" option, the script
will be removed after it was run.
If /initqueue/work is created and udev >= 143 then this loop can
process the jobs in parallel to the udevtrigger.
If the udev queue is empty and no root device is found or no root
filesystem was mounted, the user will be dropped to a shell after
a timeout.
Scripts can remove themselves from the initqueue by "rm $job".
/pre-mount/*.sh
scripts to run before the root filesystem is mounted
NFS is an exception, because it has no device node to be created
and mounts in the udev events
/mount/*.sh
scripts to mount the root filesystem
NFS is an exception, because it has no device node to be created
and mounts in the udev events
If the udev queue is empty and no root device is found or no root
filesystem was mounted, the user will be dropped to a shell after
a timeout.
/pre-pivot/*.sh
scripts to run before the real init is executed and the initramfs
disappears
All processes started before should be killed here.
The behaviour of the dmraid module demonstrates how to use the new
mechanism. If it detects a device which is part of a raidmember from a
udev rule, it installs a job to scan for dmraid devices, if the udev
queue is empty. After a scan, it removes itsself from the queue.
Udev rules set a /dev/root symlink to the real root and add
a mount script to /mount/. This enables the proper use of pre-mount
scripts and prevents mount being killed by a udev timeout.
Jobs are no longer handled inside the udev events.
/sbin/initqueue is called with the commands to queue.
init will work on these jobs sequentially, so that we prevent jobs
from being killed by udev timeouts.
This serialization also prevents some problems introduced by
the udev event parallelization.
Harald Hoyer