Re: Why is hotplug a kernel helper?

From: Fredrik Tolf
Date: Wed Dec 03 2003 - 22:39:48 EST

Greg KH writes:
> On Thu, Dec 04, 2003 at 03:00:51AM +0100, Fredrik Tolf wrote:
> > Greg KH writes:
> > > On Thu, Dec 04, 2003 at 01:04:44AM +0100, Fredrik Tolf wrote:
> > > > If you don't mind me asking, I would like to know why the kernel calls
> > > > a usermode helper for hotplug events? Wouldn't a chrdev be a better
> > > > solution (especially considering that programs like magicdev could
> > > > listen in to it as well)?
> > >
> > > Please see the archives for why this is, it's been argued many times.
> >
> > I am sincerely sorry for being a bother, but I have spent several
> > hours searching far and wide for information on it, both in the
> > archives and generally on the web, without any luck in finding
> > anything. If it's not too much to ask, would you be as kind as to
> > provide a pointer?
> Here was the latest thread where this was brought up:
> I would suggest reading this post from Linus for a quick summary:

Thank you for those references. I must have mistyped something while
searching, since all the keywords I searched for were in the
text... Sorry for wasting your time on that.

> > Btw., Is there any preferred method of announcing hotplug events to
> > user interfaces?
> Yes there is a standard. Have you read the docs at
> ? Also my 2001 OLS paper details the
> format the messages should be in, but it's a bit out of date as to the
> new values that the 2.6 kernel sends.

No, I haven't. I just put that question in the mail as a side-thing. I
had not expected more than a yes/no reply. In any case, I will read
it. Thanks again.

> What do you want to use the hotplug interface for that it currently does
> not do?

Admittedly, I'm still using the RH8 hotplug scripts, and I suspect
improvements have been made since then. I was mainly looking for a way
to auto-mount USB mass storage devices without having to reconfigure
anything as root. I have all the info I need now, though.

Thank you very much for your help.

Fredrik Tolf

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