fuse: Use generic xattr ops
In preparation for posix acl support, rework fuse to use xattr handlers and
the generic setxattr/getxattr/listxattr callbacks. Split the xattr code
out into it's own file, and promote symbols to module-global scope as
needed.
Functionally these changes have no impact, as fuse still uses a single
handler for all xattrs which uses the old callbacks.
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
diff --git a/fs/fuse/xattr.c b/fs/fuse/xattr.c
new file mode 100644
index 0000000..e22980f
--- /dev/null
+++ b/fs/fuse/xattr.c
@@ -0,0 +1,203 @@
+/*
+ * FUSE: Filesystem in Userspace
+ * Copyright (C) 2001-2016 Miklos Szeredi <miklos@szeredi.hu>
+ *
+ * This program can be distributed under the terms of the GNU GPL.
+ * See the file COPYING.
+ */
+
+#include "fuse_i.h"
+
+#include <linux/xattr.h>
+
+static int fuse_setxattr(struct inode *inode, const char *name,
+ const void *value, size_t size, int flags)
+{
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ FUSE_ARGS(args);
+ struct fuse_setxattr_in inarg;
+ int err;
+
+ if (fc->no_setxattr)
+ return -EOPNOTSUPP;
+
+ memset(&inarg, 0, sizeof(inarg));
+ inarg.size = size;
+ inarg.flags = flags;
+ args.in.h.opcode = FUSE_SETXATTR;
+ args.in.h.nodeid = get_node_id(inode);
+ args.in.numargs = 3;
+ args.in.args[0].size = sizeof(inarg);
+ args.in.args[0].value = &inarg;
+ args.in.args[1].size = strlen(name) + 1;
+ args.in.args[1].value = name;
+ args.in.args[2].size = size;
+ args.in.args[2].value = value;
+ err = fuse_simple_request(fc, &args);
+ if (err == -ENOSYS) {
+ fc->no_setxattr = 1;
+ err = -EOPNOTSUPP;
+ }
+ if (!err) {
+ fuse_invalidate_attr(inode);
+ fuse_update_ctime(inode);
+ }
+ return err;
+}
+
+static ssize_t fuse_getxattr(struct inode *inode, const char *name,
+ void *value, size_t size)
+{
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ FUSE_ARGS(args);
+ struct fuse_getxattr_in inarg;
+ struct fuse_getxattr_out outarg;
+ ssize_t ret;
+
+ if (fc->no_getxattr)
+ return -EOPNOTSUPP;
+
+ memset(&inarg, 0, sizeof(inarg));
+ inarg.size = size;
+ args.in.h.opcode = FUSE_GETXATTR;
+ args.in.h.nodeid = get_node_id(inode);
+ args.in.numargs = 2;
+ args.in.args[0].size = sizeof(inarg);
+ args.in.args[0].value = &inarg;
+ args.in.args[1].size = strlen(name) + 1;
+ args.in.args[1].value = name;
+ /* This is really two different operations rolled into one */
+ args.out.numargs = 1;
+ if (size) {
+ args.out.argvar = 1;
+ args.out.args[0].size = size;
+ args.out.args[0].value = value;
+ } else {
+ args.out.args[0].size = sizeof(outarg);
+ args.out.args[0].value = &outarg;
+ }
+ ret = fuse_simple_request(fc, &args);
+ if (!ret && !size)
+ ret = outarg.size;
+ if (ret == -ENOSYS) {
+ fc->no_getxattr = 1;
+ ret = -EOPNOTSUPP;
+ }
+ return ret;
+}
+
+static int fuse_verify_xattr_list(char *list, size_t size)
+{
+ size_t origsize = size;
+
+ while (size) {
+ size_t thislen = strnlen(list, size);
+
+ if (!thislen || thislen == size)
+ return -EIO;
+
+ size -= thislen + 1;
+ list += thislen + 1;
+ }
+
+ return origsize;
+}
+
+ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
+{
+ struct inode *inode = d_inode(entry);
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ FUSE_ARGS(args);
+ struct fuse_getxattr_in inarg;
+ struct fuse_getxattr_out outarg;
+ ssize_t ret;
+
+ if (!fuse_allow_current_process(fc))
+ return -EACCES;
+
+ if (fc->no_listxattr)
+ return -EOPNOTSUPP;
+
+ memset(&inarg, 0, sizeof(inarg));
+ inarg.size = size;
+ args.in.h.opcode = FUSE_LISTXATTR;
+ args.in.h.nodeid = get_node_id(inode);
+ args.in.numargs = 1;
+ args.in.args[0].size = sizeof(inarg);
+ args.in.args[0].value = &inarg;
+ /* This is really two different operations rolled into one */
+ args.out.numargs = 1;
+ if (size) {
+ args.out.argvar = 1;
+ args.out.args[0].size = size;
+ args.out.args[0].value = list;
+ } else {
+ args.out.args[0].size = sizeof(outarg);
+ args.out.args[0].value = &outarg;
+ }
+ ret = fuse_simple_request(fc, &args);
+ if (!ret && !size)
+ ret = outarg.size;
+ if (ret > 0 && size)
+ ret = fuse_verify_xattr_list(list, ret);
+ if (ret == -ENOSYS) {
+ fc->no_listxattr = 1;
+ ret = -EOPNOTSUPP;
+ }
+ return ret;
+}
+
+static int fuse_removexattr(struct inode *inode, const char *name)
+{
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ FUSE_ARGS(args);
+ int err;
+
+ if (fc->no_removexattr)
+ return -EOPNOTSUPP;
+
+ args.in.h.opcode = FUSE_REMOVEXATTR;
+ args.in.h.nodeid = get_node_id(inode);
+ args.in.numargs = 1;
+ args.in.args[0].size = strlen(name) + 1;
+ args.in.args[0].value = name;
+ err = fuse_simple_request(fc, &args);
+ if (err == -ENOSYS) {
+ fc->no_removexattr = 1;
+ err = -EOPNOTSUPP;
+ }
+ if (!err) {
+ fuse_invalidate_attr(inode);
+ fuse_update_ctime(inode);
+ }
+ return err;
+}
+
+static int fuse_xattr_get(const struct xattr_handler *handler,
+ struct dentry *dentry, struct inode *inode,
+ const char *name, void *value, size_t size)
+{
+ return fuse_getxattr(inode, name, value, size);
+}
+
+static int fuse_xattr_set(const struct xattr_handler *handler,
+ struct dentry *dentry, struct inode *inode,
+ const char *name, const void *value, size_t size,
+ int flags)
+{
+ if (!value)
+ return fuse_removexattr(inode, name);
+
+ return fuse_setxattr(inode, name, value, size, flags);
+}
+
+static const struct xattr_handler fuse_xattr_handler = {
+ .prefix = "",
+ .get = fuse_xattr_get,
+ .set = fuse_xattr_set,
+};
+
+const struct xattr_handler *fuse_xattr_handlers[] = {
+ &fuse_xattr_handler,
+ NULL
+};