From b6ba11773d9535fbe068232f2231c99740bb32db Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Thu, 29 Sep 2016 17:48:38 +0200 Subject: [PATCH] vfs: Move xattr_resolve_name to the front of fs/xattr.c Signed-off-by: Andreas Gruenbacher Signed-off-by: Al Viro --- fs/xattr.c | 101 ++++++++++++++++++++++++++--------------------------- 1 file changed, 50 insertions(+), 51 deletions(-) diff --git a/fs/xattr.c b/fs/xattr.c index 1f72c9217398..bb3cbbfd982d 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -24,6 +24,56 @@ #include +static const char * +strcmp_prefix(const char *a, const char *a_prefix) +{ + while (*a_prefix && *a == *a_prefix) { + a++; + a_prefix++; + } + return *a_prefix ? NULL : a; +} + +/* + * In order to implement different sets of xattr operations for each xattr + * prefix with the generic xattr API, a filesystem should create a + * null-terminated array of struct xattr_handler (one for each prefix) and + * hang a pointer to it off of the s_xattr field of the superblock. + * + * The generic_fooxattr() functions will use this list to dispatch xattr + * operations to the correct xattr_handler. + */ +#define for_each_xattr_handler(handlers, handler) \ + if (handlers) \ + for ((handler) = *(handlers)++; \ + (handler) != NULL; \ + (handler) = *(handlers)++) + +/* + * Find the xattr_handler with the matching prefix. + */ +static const struct xattr_handler * +xattr_resolve_name(const struct xattr_handler **handlers, const char **name) +{ + const struct xattr_handler *handler; + + for_each_xattr_handler(handlers, handler) { + const char *n; + + n = strcmp_prefix(*name, xattr_prefix(handler)); + if (n) { + if (!handler->prefix ^ !*n) { + if (*n) + continue; + return ERR_PTR(-EINVAL); + } + *name = n; + return handler; + } + } + return ERR_PTR(-EOPNOTSUPP); +} + /* * Check permissions for extended attribute access. This is a bit complicated * because different namespaces have very different rules. @@ -641,57 +691,6 @@ SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name) return error; } - -static const char * -strcmp_prefix(const char *a, const char *a_prefix) -{ - while (*a_prefix && *a == *a_prefix) { - a++; - a_prefix++; - } - return *a_prefix ? NULL : a; -} - -/* - * In order to implement different sets of xattr operations for each xattr - * prefix with the generic xattr API, a filesystem should create a - * null-terminated array of struct xattr_handler (one for each prefix) and - * hang a pointer to it off of the s_xattr field of the superblock. - * - * The generic_fooxattr() functions will use this list to dispatch xattr - * operations to the correct xattr_handler. - */ -#define for_each_xattr_handler(handlers, handler) \ - if (handlers) \ - for ((handler) = *(handlers)++; \ - (handler) != NULL; \ - (handler) = *(handlers)++) - -/* - * Find the xattr_handler with the matching prefix. - */ -static const struct xattr_handler * -xattr_resolve_name(const struct xattr_handler **handlers, const char **name) -{ - const struct xattr_handler *handler; - - for_each_xattr_handler(handlers, handler) { - const char *n; - - n = strcmp_prefix(*name, xattr_prefix(handler)); - if (n) { - if (!handler->prefix ^ !*n) { - if (*n) - continue; - return ERR_PTR(-EINVAL); - } - *name = n; - return handler; - } - } - return ERR_PTR(-EOPNOTSUPP); -} - /* * Find the handler for the prefix and dispatch its get() operation. */ -- 2.39.5