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authorAndy Whitcroft <apw@canonical.com>2011-11-02 09:44:39 +0100
committerChristoph Hellwig <hch@serles.lst.de>2011-11-02 12:53:42 +0100
commit1fa1e7f615f4d3ae436fa319af6e4eebdd4026a8 (patch)
treeaa3521aaa762424cc7fb38dbf924a34dac1b03c2 /fs/stat.c
parent32096ea1aac14e6f29d4744924092eca52b937b0 (diff)
downloadlwn-1fa1e7f615f4d3ae436fa319af6e4eebdd4026a8.tar.gz
lwn-1fa1e7f615f4d3ae436fa319af6e4eebdd4026a8.zip
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>
Diffstat (limited to 'fs/stat.c')
-rw-r--r--fs/stat.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/stat.c b/fs/stat.c
index 78a3aa83c7ea..8806b8997d2e 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -294,15 +294,16 @@ SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
{
struct path path;
int error;
+ int empty = 0;
if (bufsiz <= 0)
return -EINVAL;
- error = user_path_at(dfd, pathname, LOOKUP_EMPTY, &path);
+ error = user_path_at_empty(dfd, pathname, LOOKUP_EMPTY, &path, &empty);
if (!error) {
struct inode *inode = path.dentry->d_inode;
- error = -EINVAL;
+ error = empty ? -ENOENT : -EINVAL;
if (inode->i_op->readlink) {
error = security_inode_readlink(path.dentry);
if (!error) {