Date: Wed, 23 Apr 2008 15:49:54 -0400 From: John Baldwin <jhb@freebsd.org> To: Andriy Gapon <avg@icyb.net.ua> Cc: freebsd-hackers@freebsd.org Subject: Re: devctl (alike?) for devfs Message-ID: <200804231549.54722.jhb@freebsd.org> In-Reply-To: <480F8D23.9040005@icyb.net.ua> References: <480E4269.2090604@icyb.net.ua> <200804230955.10390.jhb@freebsd.org> <480F8D23.9040005@icyb.net.ua>
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On Wednesday 23 April 2008 03:25:23 pm Andriy Gapon wrote: > on 23/04/2008 16:55 John Baldwin said the following: > > On Tuesday 22 April 2008 03:54:17 pm Andriy Gapon wrote: > >> Maybe this is a crazy idea or maybe we already have something like this. > >> Is it possible to get notifications about changes in devfs - appearance > >> and disappearance of devices (in devfs sense of the word)? > >> devctl currently notifies about real (hardware) devices handled by > >> device drivers and some notifications about hardware/driver events. > >> But what if I want to automatically run some action if > >> /dev/ufs/magic-label appears? > >> Or if I want to monitor appearance and disappearance of ad* and da* > >> devices (without having to monitor low level drivers like umass)? > > > > You would just need to add new hooks to devfs to feed events to devctl when > > devices come and go. Other non-new-bus things like ifnet's already do this, > > so there is precedent. > > > > Thank you! This sounds like something rather simple, I'll try to create > a patch. > I think it would be a good idea to include "dev/" prefix in device name, > so that devfs device is not confused with "driver device" (e.g. > dev/umass0 vs umass0). Events have a subsystem associated with them, so devfs events would use their own subsystem type to avoid that sort of confusion. -- John Baldwin
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