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Re: [PATCH] Fix readdir_r with long file names
- From: Rich Felker <dalias at aerifal dot cx>
- To: Florian Weimer <fweimer at redhat dot com>
- Cc: KOSAKI Motohiro <kosaki dot motohiro at gmail dot com>, Carlos O'Donell <carlos at redhat dot com>, libc-alpha <libc-alpha at sourceware dot org>
- Date: Fri, 7 Jun 2013 10:41:43 -0400
- Subject: Re: [PATCH] Fix readdir_r with long file names
- References: <20130516125029 dot GE11420 at spoyarek dot pnq dot redhat dot com> <5194D697 dot 8040106 at redhat dot com> <20130516130952 dot GA16952 at spoyarek dot pnq dot redhat dot com> <519B58EC dot 6060108 at redhat dot com> <51B0A2F9 dot 5060004 at redhat dot com> <51B0B39F dot 4060202 at redhat dot com> <51B0BD36 dot 3030202 at redhat dot com> <CAHGf_=r9Rz63pho+84ORk0a_oDyJSj-MCnZ56uPrT3L6sVEfeQ at mail dot gmail dot com> <20130607013024 dot GO29800 at brightrain dot aerifal dot cx> <51B19203 dot 3070307 at redhat dot com>
On Fri, Jun 07, 2013 at 09:55:47AM +0200, Florian Weimer wrote:
> On 06/07/2013 03:30 AM, Rich Felker wrote:
> >On Thu, Jun 06, 2013 at 03:53:16PM -0400, KOSAKI Motohiro wrote:
> >>I mean, portable applications should use readdir_r correctly and Linux specific
> >>one should use readdir instead.
> >>
> >>Side note: the above man page is not a theoretical issue. At least, Solaris
> >>requires it.
> >>
> >>Am I missing something?
> >
> >Yes, the fact that the Austin Group is planning to require readdir to
> >be thread-safe and to mark readdir_r obsolescent.
>
> This is good news.
Very good news. I've wanted this change ever since I first learned
about readdir_r, and I'm very glad this NAME_MAX issue has provided
the push to get it done.
> > So effort put into
> >making readdir_r more usable, or worse yet, adding a readdir4, is a
> >waste of effort. Just make sure readdir_r is _safe_ against buffer
> >overflows from buggy FUSE modules, and advise application developers
> >to use readdir, not readdir_r.
>
> Does this mean that you agree with the basic approach of the patch?
Yes. I just disagree with recommending that portable applications use
readdir_r (as discussed on the Austin Group tracker/list, it has major
problems related to NAME_MAX not being mandatory) and with the idea
(by someone else, not you) to add a readdir4 rather than just
deprecating caller-provided buffers for reading directories. Those
were the only things I was commenting on.
Rich