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Date: Tue, 26 Apr 2011 11:22:26 -0400
From: Christopher Faylor <cgf-use-the-mailinglist-please AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: untarring symlinks with ../ fails randomly
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On Tue, Apr 26, 2011 at 03:08:52PM +0000, Dan Grayson wrote:
>(Re-posting yet again, didn't get through yesterday or today (?), this time
>from a different account.)
>
>
>Corinna,
>
>Debugging with gdb shows that "tar" is prepared for the possibility that
>symbolic links don't work and that hard links will have to be used instead.
>So, when it encounters a symbolic link, it creates a zero-length file with mode
>0 as a placeholder, and it records the inode number of the new file.  That way
>it can wait until all the regular files have been created, and then replace the
>placeholder by a symbolic link, or if that doesn't work, by a hard link to the
>existing file.  However, a tar file can contain multiple entries corresponding
>to the same file name or path, so it may happen that the placeholder is no
>longer present at the end, having been replaced by another file.  Hence, it
>will only replace the placeholder if the inode number and the creation time are
>unchanged.  But, under cygwin, the creation time may change gratuitously after
>the creation of the file, at random!

Cygwin doesn't change the creation time gratuitously.  Sounds like BLODA to me.

http://cygwin.com/acronyms/#BLODA

cgf

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