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

From: Walter Landry (wlandry_at_[hidden])
Date: 2005-01-19 18:03:13

"Peter Dimov" <pdimov_at_[hidden]> 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.

The only fix for that is readdir_r.  There is a comment in the docs
that readdir_r might not always be available.  This is one of those
cases where an autoconf macro would come in handy.

> 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. 

I agree.

Cheers,
Walter Landry
wlandry_at_[hidden]