Re: [boost] BUG: filesystem remove_all [PATCH]

From: Beman Dawes (bdawes_at_[hidden])
Date: 2005-01-19 19:14:56

At 06:40 AM 1/19/2005, Peter Dimov wrote:
 >Walter Landry wrote:
 >> Greetings,
 >>
 >> I have discovered a bug in the implementation of remove_all.
 >> remove_all works by reading through a directory and deleting entries
 >> along the way.  If it comes across a subdirectory, it immediately
 >> recurses into that subdirectory.  However, boost::filesystem uses
 >> readdir, which on some platforms (including OS X, apparently) uses a
 >> static data area that can be overwritten on each call to readdir.
 >> This messes up the original directory iteration, ending up with some
 >> entries not being deleted.
 >>
 >> A solution is to not recurse the directory immediately, but to make a
 >> list of them.  Once you have gone through all of the entries in a
 >> directory, then you recurse into the subdirectories.  A patch is
 >> below, although it could probably be improved.
 >
 >This patch would only fix remove_all, but the general case remains 
broken.
 >A filesystem iterator should not be affected by another filesystem
 >iterator.

Right. I'll add a test case to try to detect that happening.

 >By the way, POSIX says that readdir can only overwrite the result of
 >readdir on the same directory stream, so OS X seems to be buggy in
 >this regard.

Strange. I wonder if most OS X developers use readdir_r. Otherwise I would 
think a serious non-compliance in readdir would have been fixed a long time 
ago.

Thanks,

--Beman