• Andy Whitcroft's avatar
    readlinkat: ensure we return ENOENT for the empty pathname for normal lookups · 1fa1e7f6
    Andy Whitcroft authored
    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 65cfc672
      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: default avatarAndy 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: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
    1fa1e7f6