From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kay Sievers Date: Thu, 16 Dec 2004 21:55:02 +0000 Subject: Re: udev enhancements Message-Id: <1103234102.14134.170.camel@localhost.localdomain> List-Id: References: <41C1551F.6060601@suse.de> In-Reply-To: <41C1551F.6060601@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-hotplug@vger.kernel.org On Thu, 2004-12-16 at 10:27 +0100, Hannes Reinecke wrote: > I'm trying to figure out the best way to incorporating udev into some > system tools. Currently we're facing the following problem: > > Any program dealing with device nodes (e.g. parted) need to figure out > some information about the device it handles: > - partition naming: given a device name, generate the name of a > partition on that device. > - number of partitions: each block device type has it's own maximal > number of partitions. > > These information is mostly gathered from the device name. Of course, > you can't do that if you're using udev. Why? You still know the sysfs path with the kernel device name in it. > So, to retain the existing functionality we would need to add two major > improvements to udev: > > - Build udevinfo as library. This way any program can just link to this > library and retrieve any information from there instead of rely on some > build-in logic. That should actually be quite simple ... Why do you want to link against it? What's the problem with executing it, which is much easier to maintain? > - Add a 'dry-run' logic to udev/udevinfo: Given a devicename, how would > a partition on that device be named? > The latter is the _really_ hard part. Currently there is no relationship > in udev between a device and the partitions associated to that device. > I would love to see that, though, as it would simplify the rules and the > run-time behaviour of udev significantly. > With the current setup we have to re-run any program fetching > information about the device (e.g. scsi_id) every time a new partition > has been detected. If we had a device->partition relationship, we could > re-use the information from the device and just paste the > partition-specific bits to the end. You may just use a PROGRAM script on the partitions rule, that returns the node name of the main block device. Kay ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://productguide.itmanagersjournal.com/ _______________________________________________ Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net Linux-hotplug-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel