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author | David Howells <dhowells@redhat.com> | 2017-04-26 22:15:55 +0100 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-04-26 15:05:47 -0700 |
commit | 1e2f82d1e9d12223b4cbd1feb3f2b5596f8049eb (patch) | |
tree | 7eeeb6ba287547adc07c8fd6f916bfda60414e54 /fs | |
parent | fc08b197bb8c3bebda27b9e9884aaf7557fab53f (diff) | |
download | linux-stable-1e2f82d1e9d12223b4cbd1feb3f2b5596f8049eb.tar.gz linux-stable-1e2f82d1e9d12223b4cbd1feb3f2b5596f8049eb.tar.bz2 linux-stable-1e2f82d1e9d12223b4cbd1feb3f2b5596f8049eb.zip |
statx: Kill fd-with-NULL-path support in favour of AT_EMPTY_PATH
With the new statx() syscall, the following both allow the attributes of
the file attached to a file descriptor to be retrieved:
statx(dfd, NULL, 0, ...);
and:
statx(dfd, "", AT_EMPTY_PATH, ...);
Change the code to reject the first option, though this means copying
the path and engaging pathwalk for the fstat() equivalent. dfd can be a
non-directory provided path is "".
[ The timing of this isn't wonderful, but applying this now before we
have statx() in any released kernel, before anybody starts using the
NULL special case. - Linus ]
Fixes: a528d35e8bfc ("statx: Add a system call to make enhanced file info available")
Reported-by: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Eric Sandeen <sandeen@sandeen.net>
cc: fstests@vger.kernel.org
cc: linux-api@vger.kernel.org
cc: linux-man@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/stat.c | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/fs/stat.c b/fs/stat.c index c6c963b2546b..3d85747bd86e 100644 --- a/fs/stat.c +++ b/fs/stat.c @@ -547,13 +547,13 @@ cp_statx(const struct kstat *stat, struct statx __user *buffer) /** * sys_statx - System call to get enhanced stats * @dfd: Base directory to pathwalk from *or* fd to stat. - * @filename: File to stat *or* NULL. + * @filename: File to stat or "" with AT_EMPTY_PATH * @flags: AT_* flags to control pathwalk. * @mask: Parts of statx struct actually required. * @buffer: Result buffer. * - * Note that if filename is NULL, then it does the equivalent of fstat() using - * dfd to indicate the file of interest. + * Note that fstat() can be emulated by setting dfd to the fd of interest, + * supplying "" as the filename and setting AT_EMPTY_PATH in the flags. */ SYSCALL_DEFINE5(statx, int, dfd, const char __user *, filename, unsigned, flags, @@ -567,11 +567,10 @@ SYSCALL_DEFINE5(statx, return -EINVAL; if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE) return -EINVAL; + if (!filename) + return -EINVAL; - if (filename) - error = vfs_statx(dfd, filename, flags, &stat, mask); - else - error = vfs_statx_fd(dfd, &stat, mask, flags); + error = vfs_statx(dfd, filename, flags, &stat, mask); if (error) return error; |