site_archiver@lists.apple.com Delivered-To: darwin-dev@lists.apple.com -- Terry On Aug 8, 2008, at 4:14 AM, Tim Schooley <tim@sbdev.net> wrote: Hi all, I'm sorry if this has been answered elsewhere, but I've spent too long searching, and failed miserably to find the right answer. I have the following setup: - An IOBlockStorageDriver kext, that exposes block devices to the OS. - A daemon (running as a LaunchDaemon) which handles all block IO, and reading/writing the data to a file. - A client application for configuring the above. My problem is this: I need a way to either: Many thanks for any pointers. Kind regards, Tim _______________________________________________ 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/tlambert%40apple.com _______________________________________________ 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... A deleted files space is not reclaimed until the last reference to it goes away. An open is a reference, and a directory entry is a reference. It is quite common for UNIX programs to create a temporary file, open it, and unlink it, leaving it open, and use this as a means of having the file get automatically cleaned up if the program crashes. So you actually do not need to "detect" anything: your daemon will have absolutely no problems continuing to read, write, extend, truncate, map, or otherwise use the file contents, until the file is closed. When a file is "mounted" by the user, the daemon opens the file as normal. But the user can then remove the file from the terminal, and the daemon will be none-the-wiser. a) lock the file from the daemon side that will prevent the user from deleting the file (but allowing the user to _read_ the file). So far, my search for a solution on this has led me to believe that it isn't possible. "man chflags" does not list uulink as an option on 10.5.4, and I'm not even sure if the "rm" command would listen to it. b) code the daemon to detect the file was deleted, so it can tear down the block device. I think this may make more sense, since it removes the chance of an application or utility not abiding by the rules of a locking solution. Or, if anyone has any suggestions, I'm all ears! Either way, it'd be nice to know what other peeps would do for this situation - maybe I'm missing something fundamental. This email sent to tlambert@apple.com This email sent to site_archiver@lists.apple.com