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Subject: Re: We currently have a problem with cp -a /media/cdrom  /etc
From: James Antill <jantill@redhat.com>
To: Jim Meyering <jim@meyering.net>
Cc: SE Linux <selinux@tycho.nsa.gov>
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On Sat, 2007-01-13 at 11:05 +0100, Jim Meyering wrote:

> Isn't that fsetfilecon call useful, since your example must
> also handle an existing destination file?

 Ahh, I see. I'd somehow missed the if check before the ifdef, or not
parsed what it meant.

 Note that this does mean that:

% echo me > uid
% sudo touch ouid_r ouid_w
% sudo chmod o+w ouid_w
% cp -a uid ouid_r
cp: cannot create regular file `ouid_r': Permission denied
zsh: 25994 exit 1     cp -a uid ouid_r
% cp -a uid ouid_w
zsh: 25995 exit 1     cp -a uid ouid_w


> This is a good opportunity to ask about an old note I made:
>   - is it worthwhile to check for getfscreatecon failure?
>     The documentation says it can fail, but not how.
>     Even it's truly a "can't happen" condition now, that might change.

 IIRC it:

 open's /proc/self/task/$$/attr/fscreate
 reads the data
 malloc's the correct length for the result and copies.

...either of these three operations can fail.

> I presume the lack of a diagnostic for failed fsetfilecon
> is just an oversight.

 Yeh, probably the test case above wasn't obvious so it was hard to
test.


 So any ideas on how to make cp do the right thing in all cases ?:)

--=20
James Antill <jantill@redhat.com>

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