On Oct 7, 2009, at 11:46 AM, Dan Kegel wrote:
On Wed, Oct 7, 2009 at 9:21 AM, Ken Thomases <[email protected]>
wrote:
It would also be good to check for UF_IMMUTABLE|SF_IMMUTABLE to
determine
FILE_ATTRIBUTE_READONLY, and set UF_IMMUTABLE when setting
FILE_ATTRIBUTE_READONLY, although that's a bit of a digression from
what
you're directly working on in your patches.
Why isn't readonly enough? Geez.
Hmm? You mean Wine's current tactic of checking the mode flags to
determine READONLY?
Well, Windows itself distinguishes the READONLY attribute as separate
from having/lacking write permissions on a file.
Also, Wine's current tactic falls down in the presence of ACLs. A
file may grant no permissions in its mode bits, but grant various
access through ACLs. Wine considers such a file READONLY even if some
users (even the current user) may write to it.
Lastly, Mac OS X presents normal permissions bits, possibly including
write permission, for file systems mounted read-only. Wine reports
such files as non-READONLY if they have write bits in the mode. One
might consider this a Mac OS X bug, but, again, permissions are
different from physical writability. ("You may, but you can't." ;-)
For those reasons, I was planning to follow your patch, when it
finally gets accepted, with one to augment the current mode check with
a call to access(2) if we have a file path. If access(..., W_OK)
succeeds, I'll clear the READONLY attribute, regardless of what the
mode bits say (but respecting the [US]F_IMMUTABLE flags). If it fails
with errno == EROFS, I'll set READONLY, regardless of the mode bits.
Regards,
Ken
