Skip site navigation (1)Skip section navigation (2)
Date:      Thu, 14 May 2020 14:20:45 -0600
From:      Alan Somers <asomers@freebsd.org>
To:        "Julian H. Stacey" <jhs@berklix.com>
Cc:        Kyle Evans <kevans@freebsd.org>,  "freebsd-arch@freebsd.org" <freebsd-arch@freebsd.org>,  "freebsd-hackers@freebsd.org" <hackers@freebsd.org>
Subject:   Re: [HEADSUP] Disallowing read() of a directory fd
Message-ID:  <CAOtMX2i2Z-KX=3rYR2nZ1g1Lb_tF==H3xPKcQMBxJs1Kqr-meQ@mail.gmail.com>
In-Reply-To: <202005142017.04EKH0aA093503@fire.js.berklix.net>
References:  <CACNAnaFszg%2BQWPRS0kghsnQMxXc%2B5niPTTNiUPSmK60YyBGCzA@mail.gmail.com> <202005142017.04EKH0aA093503@fire.js.berklix.net>

next in thread | previous in thread | raw e-mail | index | archive | help
On Thu, May 14, 2020 at 2:17 PM Julian H. Stacey <jhs@berklix.com> wrote:

> Kyle Evans wrote:
> > Hi,
> >
> > This is a heads up, given that I'm completely flipping our historical
> > behavior- I intend to commit this review in a couple days' time
> > without substantial objection: https://reviews.freebsd.org/D24596
> >
> > With this, FreeBSD 13 will not allow read() of a directory fd, which
> > could have previously returned some data from the underlying
> > filesystem in no particular standardized format.
> >
> > This is a still-standards-compliant switch from one
> > implementation-defined behavior to another that's already been adopted
> > in various other popular kernels, to include OpenBSD, MacOS, and
> > Linux.
> >
> > Worth noting is that there's not really one largely-compelling reasons
> > to switch this after so many years (unless you find yourself that
> > irate when you accidentally `cat` a directory), but there are some
> > benefits which are briefly discussed in the commentary around the
> > review along with the history of the current behavior.
> >
> > This change also simplifies filesystem implementations to some extent.
> >
> > Thanks,
> >
> > Kyle Evans
>
> There is ZERO need for a spurious change at 2 days notice after 42+ years !
>
> "cat ." as been supported since Unix V6 1978 or earlier,
> no problem, even occasionaly useful.
>

Really?  When is that occasionally useful?  I've never seen anything useful
come out of reading a directory.



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAOtMX2i2Z-KX=3rYR2nZ1g1Lb_tF==H3xPKcQMBxJs1Kqr-meQ>