Date: Mon, 5 Mar 2018 18:15:08 +0200 From: Konstantin Belousov <kib@freebsd.org> To: Christoph Hellwig <hch@infradead.org> Cc: "Robert N. M. Watson" <robert.watson@cl.cam.ac.uk>, "<cl-capsicum-discuss@lists.cam.ac.uk>" <cl-capsicum-discuss@lists.cam.ac.uk>, Mariusz Zaborski <oshogbo@freebsd.org>, Justin Cormack <justin@specialbusservice.com>, freebsd-hackers@freebsd.org Subject: Re: [capsicum] unlinkfd Message-ID: <20180305161508.GE76926@kib.kiev.ua> In-Reply-To: <20180305155550.GA22789@infradead.org> References: <20180302183514.GA99279@x-wing> <CAK4o1Wyk54chHobhUkb2PBUtaWOF2rDv6tkX_bFGY6D331xUqw@mail.gmail.com> <17DE0BFF-42A2-4CD7-B09C-ABA2606C4041@cl.cam.ac.uk> <20180305155550.GA22789@infradead.org>
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On Mon, Mar 05, 2018 at 07:55:50AM -0800, Christoph Hellwig wrote: > With my Linux hat I'd much prefer using the AT_EMPTY_PATH flag that > Linux already supports for a few *at calls to operate on the dirfd > fd. But it seems like neither FreeBSD nor anyone else picked up that > flag, so it might be a bit of a hard sell. > > FreeBSD bugzilla related to AT_EMPTY_PATH and the lack of it for > unlinkat even in Linux: > > https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=197778 > > Linux bugzilla: > > https://bugzilla.kernel.org/show_bug.cgi?id=93441 > > If you are interested in bringing this to FreeBSD that might be reason > enough for me into looking into a Linux implementation as well. It is not clear from the FreeBSD PR, how unlinkat() is supposed to work. Do you mean that unlinkat(AT_EMPTY_PATH) removes the name entry for given fd, which was used for open(2) ? If yes, this is not possible to implement in the current FreeBSD VFS. Also, does linkat(AT_EMPTY_PATH) supposed to link the inode referenced only by the file descriptor ? I believe this feature is objected to.
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