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Re: Bug#497514: coreutils: chmod, chown, and chgrp change ctime even whe
From: |
Eric Blake |
Subject: |
Re: Bug#497514: coreutils: chmod, chown, and chgrp change ctime even when no change was necessary |
Date: |
Thu, 11 Sep 2008 21:20:21 -0600 |
User-agent: |
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.16) Gecko/20080708 Thunderbird/2.0.0.16 Mnenhy/0.7.5.666 |
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According to Paul Eggert on 9/11/2008 11:56 AM:
>
> As I read the spec, chown and chgrp are explicitly required to make
> the equivalent of a chown() call, which in turn is required to change
> the ctime. However, chmod is not required to make the equivalent of a
> chmod() call, and there is no requirement in the 'chmod' spec that it
> change the ctime. So POSIX allows the optimization for the 'chmod'
> command, but not for the 'chown' and 'chgrp' commands.
On the other hand, the POSIX spec for chmod(1) mentions that it is
implementation defined on how it affects alternate access control. I have
come to expect on many systems that support ACLs, that 'chmod 755' on a
file with rwxr-xr-x+ permissions will remove the ACLs. In other words,
optimizing away the chmod(2) call because it compares equal to the stat
information would break this side-effect of clearing ACLs.
- --
Don't work too hard, make some time for fun as well!
Eric Blake address@hidden
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- Re: Bug#497514: coreutils: chmod, chown, and chgrp change ctime even when no change was necessary, Jim Meyering, 2008/09/02
- Re: Bug#497514: coreutils: chmod, chown, and chgrp change ctime even when no change was necessary, Erik Rossen, 2008/09/02
- Re: Bug#497514: coreutils: chmod, chown, and chgrp change ctime even when no change was necessary, Paul Eggert, 2008/09/11
- Re: Bug#497514: coreutils: chmod, chown, and chgrp change ctime even when no change was necessary,
Eric Blake <=
- Re: Bug#497514: coreutils: chmod, chown, and chgrp change ctime even when no change was necessary, Jim Meyering, 2008/09/12
- Re: Bug#497514: coreutils: chmod, chown, and chgrp change ctime even when no change was necessary, Michael Stone, 2008/09/12
- Re: Bug#497514: coreutils: chmod, chown, and chgrp change ctime even when no change was necessary, Jim Meyering, 2008/09/13