/etc/hotplug or /etc/hotplug.d ?

[martin f krafft <madduck@madduck.net>]

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Hi folks,

I develop the user-space driver for a USB device (libphidgets). To
be able to make it as easy as possible to my users, I want to
register a hotplug hook that chmod's the /proc/bus/usb/*/* file to
0660:root:phidgets upon connection, so that (only) members of the
phidgets group can use it.

There seem to be two approaches.

At first, I was using a simple script in /etc/hotplug/usb:

  http://cvs.ailab.ch/cgi-bin/viewcvs.cgi/external/libphidgets/hotplug/Attic/phidgets?rev=1.2&view=auto

along with a user map entry to have the script called upon insertion
of a USB device with a certain ID pair:

  http://cvs.ailab.ch/cgi-bin/viewcvs.cgi/external/libphidgets/hotplug/Attic/phidgets.usermap?rev=1.2&view=auto

Greg KH suggested to me not to bother with the usermaps and instead
provide a script in /etc/hotplug.d/usb instead. So I did:

  http://cvs.ailab.ch/cgi-bin/viewcvs.cgi/external/libphidgets/hotplug/phidgets.hotplug?rev=1.3&view=auto

Both approaches work. However, now I am being told that it is
"better" to use /etc/hotplug (like I did in the first approach).
I was unable to squeeze any real arguments out of the person
asserting this.

But it got me thinking, so I want to find the real answer now.

Using /etc/hotplug.d/usb seems to have the advantage that it does
not need the usermap, but it's called for every USB device ever
inserted.

/etc/hotplug/usb is only called if the usermap line matches. It
requires the line to specify a script to be called. However, scripts
are also called upon loading of a module by the same name by
hotplug, so there is a potential source of conflict.

What's your opinion? Which hook should I prefer?

Thanks,

-- 
martin;              (greetings from the heart of the sun.)
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