From: Jeff Garzik <jeff@garzik.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>,
jeremy@goop.org, jengelh@computergmbh.de, viro@ftp.linux.org.uk,
nmiell@comcast.net, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: *at syscalls for xattrs?
Date: Mon, 16 Jul 2007 05:47:46 -0400 [thread overview]
Message-ID: <469B3EC2.8080702@garzik.org> (raw)
In-Reply-To: <469B3B73.9010400@zytor.com>
H. Peter Anvin wrote:
> Miklos Szeredi wrote:
>> The *at() thing basically gives you the advantages of a CWD without
>> the disadvantages.
>>
>> For example it could be useful to implement the functionality of
>> find(1) as a library interface.
>>
>
> What the *at() interfaces really do is fix/paper over a longstanding
> wart in Unix: the cwd really should have been a standard file descriptor
> (like stdin/stdout/stderr) instead of a magic piece of state maintained
> in kernel space.
It's more than a wart, IMO. *at() allows one to close races (with
potential security implications) that are otherwise impossible to close,
in directory traversal.
*at() permits a userspace program to hold proper references to all
objects during a directory traversal, with all that implies.
Jeff
next prev parent reply other threads:[~2007-07-16 9:48 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-15 19:46 *at syscalls for xattrs? Jan Engelhardt
2007-07-15 20:53 ` Al Viro
2007-07-15 21:13 ` Nicholas Miell
2007-07-15 22:23 ` Al Viro
2007-07-15 23:09 ` H. Peter Anvin
2007-07-16 7:56 ` Jan Engelhardt
2007-07-16 8:04 ` Al Viro
2007-07-16 8:30 ` Jeremy Fitzhardinge
2007-07-16 9:05 ` Miklos Szeredi
2007-07-16 9:33 ` H. Peter Anvin
2007-07-16 9:47 ` Jeff Garzik [this message]
2007-07-16 17:57 ` H. Peter Anvin
2007-07-16 20:03 ` Jeff Garzik
2007-07-16 20:40 ` H. Peter Anvin
2007-07-16 9:12 ` Andreas Schwab
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