www.nico.schottelius.org/blog/about-init-dependencies.mdwn

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[[!meta title="About init dependencies"]]
As i started to hack on [cinit](http://unix.schottelius.org/cinit/) again,
I tried to get it running on Debian in a VM.
I took the old configuration from my last computer and tried to boot
with cinit, which failed, because the udev stuff changed.
So I added a udev service, which uses /etc/init.d/udev for switching on.
After booting the VM, I recognized, that the service
***mount/proc*** (which mounts /proc...) fails. Mount claims that
/proc it is already mounted!
This is caused by the udev script, which contains:
237 [ -d /proc/1 ] || mount -n /proc
Besides the problematic of using a sys-v-init script with an
intelligent init system, it's interesting to see, **why**
this happens:
The service mount/root needs the device files in /dev
to be able to run mount/root/fsck (the filesystem check).
Thus mount/root requires the service udev to be started before.
The service mount/proc needs the root filesystems writable,
to write into /etc/mtab and thus needs mount/root.
This also demonstrates the problematic of the historical grown
init scripts, which do way more than one job and their lack of
real dependencies.
[[!tag unix]]