udevstart: a question

udevstart: a question

[Ryan Reich]

If you respond, please CC me, since I'm not subscribed.

This isn't a problem so much as a puzzled query: what's the purpose of the udev
init script now that udevstart exists?  It does exactly the same thing except
create those symlinks which appeared in the udev-021 init script, except that it
is a standalone program.  In particular, it doesn't suffer from the vexing error
which arises when you try to create a /dev from scratch and bash complains about
the nonexistence of /dev/null from which to redirect standard input (though I'm
told sash doesn't do this; still, it's a bother).  You don't even need the init
script to start udevd, since it gets called if it doesn't already exist the
first time udevsend is called by hotplug.

Okay, I can see one purpose for the init script still: to "stop" udev.  This is
a reasonable objection to the previous paragraph; however, you have to ask
yourself what the point is of such a function.  Stopping udev removes all device
files from your /dev, which is undesirable.  I can see that one might like the
ability to replace the dynamic udev-managed /dev with a static /dev under some
circumstances; however, surely this can be arranged more elegantly by having the
init script mount a tmpfs or ramfs filesystem and then simply unmounting it to
reveal the old, static /dev below.

I suggest that the following method for managing /dev be used: create a tmpfs
filesystem on top of /dev either in an initrd or in an init script, and populate
it using udevstart.  To "stop" udev you simply unmount this filesystem.  The
extra symlinks are easy to take care of either in the initrd's /linuxrc or in
the init script, as now.

-- 
Ryan Reich
ryanr@uchicago.edu


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Re: udevstart: a question

[Greg KH]

On Fri, Mar 12, 2004 at 05:08:09PM -0600, Ryan Reich wrote:
> If you respond, please CC me, since I'm not subscribed.
> 
> This isn't a problem so much as a puzzled query: what's the purpose of the udev
> init script now that udevstart exists?

As a "example" of how you could intregrate udev into your distro if you
want to?

I agree, now that we have udevstart, the init script isn't really
needed.  But I'll keep it around for a while until all of the distros
figure out what they are going to do.

If nothing else, they can call udevstart within the init script :)

thanks,

greg k-h


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