site_archiver@lists.apple.com Delivered-To: darwin-dev@lists.apple.com Cheers, - Dean _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.appl... On Mar 15, 2008, at 10:35 AM, Duane Murphy wrote: Hi Folks, I'm installing a kext in /System/Library/Extensions. On Leopard we are having trouble with the kext cache for a boot partition not getting updated properly when the kext is installed. Of course this results in the system becoming unbootable because the cache is out of sync (at least that's what the output at boot time says). We are following the usual guidelines, but I get the idea that the usual guidelines may not be appropriate for Leopard. The installer puts the kext folder into /System/Library/Extensions then we do the chmod, chown dance to set privileges correctly, then finally touch /S/L/E. I believe that on Leopard, kextcache is launched as a result of using the new FSEvents mechanism. This in turn causes kextcache to be kicked off when the folder is installed before the privilege dance can be finished causing the cache to get out of sync. kextd is watching the extensions folder, so the final touch you do should (re)trigger the cache rebuild. If you are doing a touch after the kext install & perm dance, and the cache is not being rebuilt correctly, you need to file a radar. It has been recommended to me previously to do the privilege dance outside of /S/L/E and then move the kext into /S/L/E. The question then becomes where is a good place to stage the kext? And is this the right thing to do? Yes, it is the best thing to do on any version of OS X, since it guarantees you won't end up with a partially installed or updated kext if the system crashes at just the wrong time. On Leopard, kextd watches /S/L/E and it might rebuild more than once if the mod date of /S/L/E changes multiple times during your installation process. Using mv will make the kext installation atomic, so the kext can't be partially installed. As long as the final touch happens within a few seconds after the mv, kextache will only be run once. The target directory should be on the same volume as /S/L/E and support privileges (ie not have the "ignore privileges on this volume" switch turned on). Is just using /S/L appropriate? You should not modify /S/L; that is only for Apple. In the future, we may provide a condoned staging area for this and/or a kext install script that you can just run from your installer, but for now, you need to find some other place to do this. /tmp seems scary to me. Seems to easy (and to common) to remap to a different volume for expert users. It is certainly possible, though the worst-case side effect of it being on a different volume is that the mv degrades to a cp. As long as you always followup with a touch of /S/L/E , then kextcache should rebuild with your complete kext (please file a radar if not). Alternatively, you can install your kext with a different extension, and rename it to foo.kext after you've completed the install/perm dance. Then, one final touch to /S/L/E and you should be good. Seems like this change to kext loading could affect lots of installations if I am correct. I am not aware of other reports of this, so if there is a bug in the cache rebuild logic, it isn't being widely seen or reported. Thank you for your comments and recommendations. This email sent to site_archiver@lists.apple.com