From: Andy Whitcroft <apw@canonical.com>
Date: Wed, 2 Nov 2011 08:44:39 +0000 (+0100)
Subject: readlinkat: ensure we return ENOENT for the empty pathname for normal lookups
X-Git-Tag: v3.2-rc1~84^2~9
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1fa1e7f615f4d3ae436fa319af6e4eebdd4026a8;p=pandora-kernel.git

readlinkat: ensure we return ENOENT for the empty pathname for normal lookups

Since the commit below which added O_PATH support to the *at() calls, the
error return for readlink/readlinkat for the empty pathname has switched
from ENOENT to EINVAL:

  commit 65cfc6722361570bfe255698d9cd4dccaf47570d
  Author: Al Viro <viro@zeniv.linux.org.uk>
  Date:   Sun Mar 13 15:56:26 2011 -0400

    readlinkat(), fchownat() and fstatat() with empty relative pathnames

This is both unexpected for userspace and makes readlink/readlinkat
inconsistant with all other interfaces; and inconsistant with our stated
return for these pathnames.

As the readlinkat call does not have a flags parameter we cannot use the
AT_EMPTY_PATH approach used in the other calls.  Therefore expose whether
the original path is infact entry via a new user_path_at_empty() path
lookup function.  Use this to determine whether to default to EINVAL or
ENOENT for failures.

Addresses http://bugs.launchpad.net/bugs/817187

[akpm@linux-foundation.org: remove unused getname_flags()]
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---

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