From: Linus Torvalds <torvalds@linux-foundation.org>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
LSM List <linux-security-module@vger.kernel.org>,
Miklos Szeredi <miklos@szeredi.hu>,
David Howells <dhowells@redhat.com>
Subject: Re: [RFC] readlink()-related oddities
Date: Thu, 19 Nov 2015 18:13:53 -0800 [thread overview]
Message-ID: <CA+55aFx_=L4adTfn=bZ8oK2b-j-+satDhTsaZUGvcVmJ81A_RQ@mail.gmail.com> (raw)
In-Reply-To: <20151119232635.GI22011@ZenIV.linux.org.uk>
On Thu, Nov 19, 2015 at 3:26 PM, Al Viro <viro@zeniv.linux.org.uk> wrote:
>
> 1) atime updates, according to POSIX, should happen in case of success.
> For example, giving readlink(2) an unmapped buffer should _not_ touch
> atime. Neither should calling readlink(2) in case if ->readlink() method
> returns e.g. -EIO or -ENOMEM. We do atime update in those cases. Looks
> like a bug and unless there's a good reason to keep that behaviour, I'd
> rather have it do what POSIX says.
I really don't think anybody cares, but I also don't think anybody
cares about the current behavior, so we can certainly fix it to match
POSIX wording, and just move it a bit lower after checking the return
value from ->realink().
> 3) normally, readlink(2) fails for non-symlinks. Moreover, according to
> POSIX it should do so (with -EINVAL).
I don't think POSIX is necessarily relevant here.
We have had magic file behavior outside the scope of POSIX before, and
we will have it in the future. It makes perfect sense to use
readlink() for management tools for automounting, even if the normal
oepration is to treat the thing as a directory.
Not everything is within the domain of POSIX.
Linus
next prev parent reply other threads:[~2015-11-20 2:13 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-19 23:26 [RFC] readlink()-related oddities Al Viro
2015-11-20 2:13 ` Linus Torvalds [this message]
2015-11-20 2:57 ` Al Viro
2015-11-20 3:09 ` Linus Torvalds
2015-11-20 3:16 ` Linus Torvalds
2015-11-20 3:24 ` Al Viro
2015-11-20 10:00 ` David Howells
2015-11-20 9:59 ` David Howells
2015-11-20 16:08 ` Al Viro
2015-11-20 16:26 ` David Howells
2015-11-20 22:33 ` Al Viro
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CA+55aFx_=L4adTfn=bZ8oK2b-j-+satDhTsaZUGvcVmJ81A_RQ@mail.gmail.com' \
--to=torvalds@linux-foundation.org \
--cc=dhowells@redhat.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
--cc=miklos@szeredi.hu \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).