@@ -247,6 +247,8 @@ extern const struct dentry_operations ns_dentry_operations;
int getname_statx_lookup_flags(int flags);
int do_statx(int dfd, struct filename *filename, unsigned int flags,
unsigned int mask, struct statx __user *buffer);
+int do_statx_fd(int fd, unsigned int flags, unsigned int mask,
+ struct statx __user *buffer);
/*
* fs/splice.c:
@@ -321,3 +323,15 @@ struct stashed_operations {
int path_from_stashed(struct dentry **stashed, struct vfsmount *mnt, void *data,
struct path *path);
void stashed_dentry_prune(struct dentry *dentry);
+/**
+ * path_mounted - check whether path is mounted
+ * @path: path to check
+ *
+ * Determine whether @path refers to the root of a mount.
+ *
+ * Return: true if @path is the root of a mount, false if not.
+ */
+static inline bool path_mounted(const struct path *path)
+{
+ return path->mnt->mnt_root == path->dentry;
+}
@@ -1846,19 +1846,6 @@ bool may_mount(void)
return ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_ADMIN);
}
-/**
- * path_mounted - check whether path is mounted
- * @path: path to check
- *
- * Determine whether @path refers to the root of a mount.
- *
- * Return: true if @path is the root of a mount, false if not.
- */
-static inline bool path_mounted(const struct path *path)
-{
- return path->mnt->mnt_root == path->dentry;
-}
-
static void warn_mandlock(void)
{
pr_warn_once("=======================================================\n"
@@ -214,6 +214,43 @@ int getname_statx_lookup_flags(int flags)
return lookup_flags;
}
+static int vfs_statx_path(struct path *path, int flags, struct kstat *stat,
+ u32 request_mask)
+{
+ int error = vfs_getattr(path, stat, request_mask, flags);
+
+ if (request_mask & STATX_MNT_ID_UNIQUE) {
+ stat->mnt_id = real_mount(path->mnt)->mnt_id_unique;
+ stat->result_mask |= STATX_MNT_ID_UNIQUE;
+ } else {
+ stat->mnt_id = real_mount(path->mnt)->mnt_id;
+ stat->result_mask |= STATX_MNT_ID;
+ }
+
+ if (path_mounted(path))
+ stat->attributes |= STATX_ATTR_MOUNT_ROOT;
+ stat->attributes_mask |= STATX_ATTR_MOUNT_ROOT;
+
+ /* Handle STATX_DIOALIGN for block devices. */
+ if (request_mask & STATX_DIOALIGN) {
+ struct inode *inode = d_backing_inode(path->dentry);
+
+ if (S_ISBLK(inode->i_mode))
+ bdev_statx_dioalign(inode, stat);
+ }
+
+ return error;
+}
+
+static int vfs_statx_fd(int fd, int flags, struct kstat *stat,
+ u32 request_mask)
+{
+ CLASS(fd_raw, f)(fd);
+ if (!f.file)
+ return -EBADF;
+ return vfs_statx_path(&f.file->f_path, flags, stat, request_mask);
+}
+
/**
* vfs_statx - Get basic and extra attributes by filename
* @dfd: A file descriptor representing the base dir for a relative filename
@@ -243,36 +280,13 @@ static int vfs_statx(int dfd, struct filename *filename, int flags,
retry:
error = filename_lookup(dfd, filename, lookup_flags, &path, NULL);
if (error)
- goto out;
-
- error = vfs_getattr(&path, stat, request_mask, flags);
-
- if (request_mask & STATX_MNT_ID_UNIQUE) {
- stat->mnt_id = real_mount(path.mnt)->mnt_id_unique;
- stat->result_mask |= STATX_MNT_ID_UNIQUE;
- } else {
- stat->mnt_id = real_mount(path.mnt)->mnt_id;
- stat->result_mask |= STATX_MNT_ID;
- }
-
- if (path.mnt->mnt_root == path.dentry)
- stat->attributes |= STATX_ATTR_MOUNT_ROOT;
- stat->attributes_mask |= STATX_ATTR_MOUNT_ROOT;
-
- /* Handle STATX_DIOALIGN for block devices. */
- if (request_mask & STATX_DIOALIGN) {
- struct inode *inode = d_backing_inode(path.dentry);
-
- if (S_ISBLK(inode->i_mode))
- bdev_statx_dioalign(inode, stat);
- }
-
+ return error;
+ error = vfs_statx_path(&path, flags, stat, request_mask);
path_put(&path);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
-out:
return error;
}
@@ -666,7 +680,8 @@ int do_statx(int dfd, struct filename *filename, unsigned int flags,
if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE)
return -EINVAL;
- /* STATX_CHANGE_COOKIE is kernel-only for now. Ignore requests
+ /*
+ * STATX_CHANGE_COOKIE is kernel-only for now. Ignore requests
* from userland.
*/
mask &= ~STATX_CHANGE_COOKIE;
@@ -678,16 +693,41 @@ int do_statx(int dfd, struct filename *filename, unsigned int flags,
return cp_statx(&stat, buffer);
}
+int do_statx_fd(int fd, unsigned int flags, unsigned int mask,
+ struct statx __user *buffer)
+{
+ struct kstat stat;
+ int error;
+
+ if (mask & STATX__RESERVED)
+ return -EINVAL;
+ if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE)
+ return -EINVAL;
+
+ /*
+ * STATX_CHANGE_COOKIE is kernel-only for now. Ignore requests
+ * from userland.
+ */
+ mask &= ~STATX_CHANGE_COOKIE;
+
+ error = vfs_statx_fd(fd, flags, &stat, mask);
+ if (error)
+ return error;
+
+ return cp_statx(&stat, buffer);
+}
+
/**
* sys_statx - System call to get enhanced stats
* @dfd: Base directory to pathwalk from *or* fd to stat.
- * @filename: File to stat or "" with AT_EMPTY_PATH
+ * @filename: File to stat or either NULL or "" with AT_EMPTY_PATH
* @flags: AT_* flags to control pathwalk.
* @mask: Parts of statx struct actually required.
* @buffer: Result buffer.
*
* 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.
+ * supplying "" (or preferably NULL) as the filename and setting AT_EMPTY_PATH
+ * in the flags.
*/
SYSCALL_DEFINE5(statx,
int, dfd, const char __user *, filename, unsigned, flags,
@@ -695,8 +735,23 @@ SYSCALL_DEFINE5(statx,
struct statx __user *, buffer)
{
int ret;
+ unsigned lflags;
struct filename *name;
+ /*
+ * Short-circuit handling of NULL and "" paths.
+ *
+ * For a NULL path we require and accept only the AT_EMPTY_PATH flag
+ * (possibly |'d with AT_STATX flags).
+ *
+ * However, glibc on 32-bit architectures implements fstatat as statx
+ * with the "" pathname and AT_NO_AUTOMOUNT | AT_EMPTY_PATH flags.
+ * Supporting this results in the uglification below.
+ */
+ lflags = flags & ~(AT_NO_AUTOMOUNT | AT_STATX_SYNC_TYPE);
+ if (lflags == AT_EMPTY_PATH && vfs_empty_path(dfd, filename))
+ return do_statx_fd(dfd, flags & ~AT_NO_AUTOMOUNT, mask, buffer);
+
name = getname_flags(filename, getname_statx_lookup_flags(flags), NULL);
ret = do_statx(dfd, name, flags, mask, buffer);
putname(name);