Thursday, September 16, 2010

Resetting permissions from the OS X 10.5 and 10.6 Installation DVD

The Installation DVD has the ability to reset permissions using, oddly enough, the "reset password" utility. CNET Fix-It describes this tool in the context of moving files between user account and resetting their permissions..

How-To: Migrating to a new user account in OS X | MacFixIt - CNET Reviews:

Insert your OS X installation DVD (the gray restore DVD that came with your computer should work) and boot from it by restarting while holding the 'C' key down.
Select your language and choose 'Reset Password' from the 'Utilities' menu.
In this utility, you can reset the permissions on your home directory, so follow the instructions to do that on your new account.
When the permissions have been reset, reboot the system with the 'Shift' key held down (it boots to 'Safe Mode') and try logging in to your new account.
If everything is successful, then reboot normally.
Go to the 'Accounts' system preferences and remove your old account, choosing the option to delete the home folder for that account.
I'd never heard of this 10.5 (Leopard) feature. The utility can be used to cure a permission bug related to "apply to enclosed items" that afflicted me in 10.5MacWorld describes the permissions fix, and the bug, best ...
... the permissions problem ...  can arise if you make a change to the Sharing and Permissions listings in the Finder’s Info window for a folder in your Home directory, and then select the “Apply to enclosed items” option from the Info window’s Action pop-up menu. You’re especially likely to see these symptoms if you do this for the Home directory itself, but I believe the issue can also arise if you perform the action on subfolders...

... sudo chmod -RN ~ ... removes all Access Control List (ACL) modifications from all items in your Home directory. These modifications can come from certain changes made to the Sharing & Permissions section of an Info window.

Next, start up from a Leopard Install DVD and select Reset Password from the Utilities menu. Here is where the new feature appears. This utility has been around for quite awhile, certainly prior to Leopard. However, the Leopard version sports a new option—Reset Home Directory Permissions and ACLs.

... it’s not clear (at least not to me, with my limited UNIX background) why the Terminal command is even needed, as the Reset Password action appears to include what the command does. I could not find any documentation for the Reset Home Directory Permissions and ACLs action, so I could not confirm this for sure.

Second, it is not clear whether the symptoms are due to a bug in how “Apply to enclosed items” works, which Apple will hopefully fix—or if you are simply never supposed to use the command with your Home directory.
Is this a good time to mention that I hate OS X Permissions.

I checked my copy of the Tidbits book "Take Control of OS X Permissions" but they seem to have missed this one. I'll send in a reference to this post so they can add it with the next update.

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