From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Date: Fri, 27 May 2005 21:51:55 +0000 Subject: Re: udev and sysfs permissions Message-Id: <20050527215155.GB2225@kroah.com> List-Id: References: <9e47339105051915025188e535@mail.gmail.com> In-Reply-To: <9e47339105051915025188e535@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-hotplug@vger.kernel.org On Fri, May 27, 2005 at 06:02:28PM +0530, Maneesh Soni wrote: > On Thu, May 26, 2005 at 04:09:51PM -0700, Greg KH wrote: > > On Sat, May 21, 2005 at 12:07:23AM +0200, Kay Sievers wrote: > > > On Fri, 2005-05-20 at 17:53 -0400, Jon Smirl wrote: > > > > On 5/20/05, Greg KH wrote: > > > > > On Fri, May 20, 2005 at 05:40:05PM -0400, Jon Smirl wrote: > > > > > > On 5/20/05, Greg KH wrote: > > > > > > > > That would make things simpler for driver writers if more devices are > > > > > > > > going to follow this model. > > > > > > > > > > > > > > I think you are going to be pretty unique here, as no one else has come > > > > > > > up with a situation yet that requires this. > > > > > > > > > > > > If the mantra about sysfs attributes being superior to IOCTLs is true, > > > > > > then anyone who converts to sysfs attributes is going to run into this > > > > > > problem. In the IOCTL model permission obviously follows the owner of > > > > > > the /dev device. There is no parallel for this in the sysfs model. > > > > > > > > > > True. Hm, let me look into the sysfs code to see if we can just save > > > > > the changed attributes, so that they do not get lost. That would be the > > > > > simplest solution, right? > > > > Ugh, in trying to figure this out for the past few days, I've gotten no > > where at all :( > > > > Maneesh, any chance we could get some help? The issue is, if a user > > changes the owner:group or permissions on a sysfs file, it would be nice > > to have those changes stay. Due to the backing-store changes, over > > time, the sysfs files are re-created, and those user-made changes are > > lost. I've poked around in sysfs, and tried to add some new functions > > for the vfs to call when an inode is dirty, but had no luck at all in > > getting this to work. Any ideas? > > > > It should be doable. But again this will increase the size of sysfs_dirent > structure. If I am not wrong we will need to save (persistent) struct iattr > for each sysfs_dirent there by increasing its size by 52 bytes on i386 and > we will need ->i_op->setattr() and ->i_op->getattr() routines for sysfs. Why do we need to increase the size? We already save the mode in the sysfs_dirent, right? Isn't that all that is needed? When the setattr() function is called we can modify our s_mode variable. Or am I missing something obvious here? > Do we need this functionality in all sysfs objects or only for certain type > of sysfs objects? Well, we don't really know which ones we need it for :( If it's going to take up 52 extra bytes for every sysfs file in the tree, that might not be worth it. thanks, greg k-h ------------------------------------------------------- This SF.Net email is sponsored by Yahoo. Introducing Yahoo! Search Developer Network - Create apps using Yahoo! Search APIs Find out how you can build Yahoo! directly into your own Applications - visit http://developer.yahoo.net/?fr=offad-ysdn-ostg-q22005 _______________________________________________ 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