1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 File: linux/xattr.h 4 5 Extended attributes handling. 6 7 Copyright (C) 2001 by Andreas Gruenbacher <a.gruenbacher@computer.org> 8 Copyright (c) 2001-2002 Silicon Graphics, Inc. All Rights Reserved. 9 Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> 10 */ 11 #ifndef _LINUX_XATTR_H 12 #define _LINUX_XATTR_H 13 14 15 #include <linux/slab.h> 16 #include <linux/types.h> 17 #include <linux/spinlock.h> 18 #include <linux/mm.h> 19 #include <linux/user_namespace.h> 20 #include <uapi/linux/xattr.h> 21 22 /* List of all open_how "versions". */ 23 #define XATTR_ARGS_SIZE_VER0 16 /* sizeof first published struct */ 24 #define XATTR_ARGS_SIZE_LATEST XATTR_ARGS_SIZE_VER0 25 26 struct inode; 27 struct dentry; 28 29 static inline bool is_posix_acl_xattr(const char *name) 30 { 31 return (strcmp(name, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || 32 (strcmp(name, XATTR_NAME_POSIX_ACL_DEFAULT) == 0); 33 } 34 35 /* 36 * struct xattr_handler: When @name is set, match attributes with exactly that 37 * name. When @prefix is set instead, match attributes with that prefix and 38 * with a non-empty suffix. 39 */ 40 struct xattr_handler { 41 const char *name; 42 const char *prefix; 43 int flags; /* fs private flags */ 44 bool (*list)(struct dentry *dentry); 45 int (*get)(const struct xattr_handler *, struct dentry *dentry, 46 struct inode *inode, const char *name, void *buffer, 47 size_t size); 48 int (*set)(const struct xattr_handler *, 49 struct mnt_idmap *idmap, struct dentry *dentry, 50 struct inode *inode, const char *name, const void *buffer, 51 size_t size, int flags); 52 }; 53 54 /** 55 * xattr_handler_can_list - check whether xattr can be listed 56 * @handler: handler for this type of xattr 57 * @dentry: dentry whose inode xattr to list 58 * 59 * Determine whether the xattr associated with @dentry can be listed given 60 * @handler. 61 * 62 * Return: true if xattr can be listed, false if not. 63 */ 64 static inline bool xattr_handler_can_list(const struct xattr_handler *handler, 65 struct dentry *dentry) 66 { 67 return handler && (!handler->list || handler->list(dentry)); 68 } 69 70 const char *xattr_full_name(const struct xattr_handler *, const char *); 71 72 struct xattr { 73 const char *name; 74 void *value; 75 size_t value_len; 76 }; 77 78 ssize_t __vfs_getxattr(struct dentry *, struct inode *, const char *, void *, size_t); 79 ssize_t vfs_getxattr(struct mnt_idmap *, struct dentry *, const char *, 80 void *, size_t); 81 ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size); 82 int __vfs_setxattr(struct mnt_idmap *, struct dentry *, struct inode *, 83 const char *, const void *, size_t, int); 84 int __vfs_setxattr_noperm(struct mnt_idmap *, struct dentry *, 85 const char *, const void *, size_t, int); 86 int __vfs_setxattr_locked(struct mnt_idmap *, struct dentry *, 87 const char *, const void *, size_t, int, 88 struct inode **); 89 int vfs_setxattr(struct mnt_idmap *, struct dentry *, const char *, 90 const void *, size_t, int); 91 int __vfs_removexattr(struct mnt_idmap *, struct dentry *, const char *); 92 int __vfs_removexattr_locked(struct mnt_idmap *, struct dentry *, 93 const char *, struct inode **); 94 int vfs_removexattr(struct mnt_idmap *, struct dentry *, const char *); 95 96 ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size); 97 int vfs_getxattr_alloc(struct mnt_idmap *idmap, 98 struct dentry *dentry, const char *name, 99 char **xattr_value, size_t size, gfp_t flags); 100 101 int xattr_supports_user_prefix(struct inode *inode); 102 103 static inline const char *xattr_prefix(const struct xattr_handler *handler) 104 { 105 return handler->prefix ?: handler->name; 106 } 107 108 struct simple_xattrs { 109 struct rb_root rb_root; 110 rwlock_t lock; 111 }; 112 113 struct simple_xattr { 114 struct rb_node rb_node; 115 char *name; 116 size_t size; 117 char value[]; 118 }; 119 120 void simple_xattrs_init(struct simple_xattrs *xattrs); 121 void simple_xattrs_free(struct simple_xattrs *xattrs, size_t *freed_space); 122 size_t simple_xattr_space(const char *name, size_t size); 123 struct simple_xattr *simple_xattr_alloc(const void *value, size_t size); 124 void simple_xattr_free(struct simple_xattr *xattr); 125 int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, 126 void *buffer, size_t size); 127 struct simple_xattr *simple_xattr_set(struct simple_xattrs *xattrs, 128 const char *name, const void *value, 129 size_t size, int flags); 130 ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, 131 char *buffer, size_t size); 132 void simple_xattr_add(struct simple_xattrs *xattrs, 133 struct simple_xattr *new_xattr); 134 int xattr_list_one(char **buffer, ssize_t *remaining_size, const char *name); 135 136 #endif /* _LINUX_XATTR_H */ 137