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To: cygwin <cygwin AT cygwin DOT com>
From: Eliot Moss <moss AT cs DOT umass DOT edu>
Subject: A notion about saving and restoring Windows file security info
Message-ID: <4c5fda33-8f7e-53d2-85ce-28eb11cfb978@cs.umass.edu>
Date: Tue, 4 Jan 2022 22:45:29 -0500
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Dear Cygwiners - Maybe this idea has been discussed before, and I can't say I
exactly have a specific application in mind, but I was wondering about how one
might achieve reliable backup/restore of files on a Windows system via a
backup program written to the POSIX interface and ported to Windows via
Cygwin.

The idea is this: expose the Windows file attributes (such as system, archive,
hidden, etc.) as well as security descriptors (such as managed by icacls), via
specifically named extended attributes, those read/written by get/setfattr.
The Cygwin library could be enhanced to "know" the special names of these
attributes and use the appropriate, different, underlying calls to get/set
them.

Is this a crazy idea?  A useful one?  (How useful?)  What implementation
effort would be required?

What brought it to mind is the restic backup/restore program, which AFAIK
lacks support for these things, but does know how to save/restore xattrs.  (So
I could fake the same thing there, provided I duplicate in golang in restic
what I am suggesting might be done for Cygwin in it library.)

Regards - Eliot

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