LXR linux/include/linux/xattr.h

   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 <uapi/linux/xattr.h>
  19
  20struct inode;
  21struct dentry;
  22
  23/*
  24 * struct xattr_handler: When @name is set, match attributes with exactly that
  25 * name.  When @prefix is set instead, match attributes with that prefix and
  26 * with a non-empty suffix.
  27 */
  28struct xattr_handler {
  29        const char *name;
  30        const char *prefix;
  31        int flags;      /* fs private flags */
  32        bool (*list)(struct dentry *dentry);
  33        int (*get)(const struct xattr_handler *, struct dentry *dentry,
  34                   struct inode *inode, const char *name, void *buffer,
  35                   size_t size);
  36        int (*set)(const struct xattr_handler *, struct dentry *dentry,
  37                   struct inode *inode, const char *name, const void *buffer,
  38                   size_t size, int flags);
  39};
  40
  41const char *xattr_full_name(const struct xattr_handler *, const char *);
  42
  43struct xattr {
  44        const char *name;
  45        void *value;
  46        size_t value_len;
  47};
  48
  49ssize_t xattr_getsecurity(struct inode *, const char *, void *, size_t);
  50ssize_t __vfs_getxattr(struct dentry *, struct inode *, const char *, void *, size_t);
  51ssize_t vfs_getxattr(struct dentry *, const char *, void *, size_t);
  52ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);
  53int __vfs_setxattr(struct dentry *, struct inode *, const char *, const void *, size_t, int);
  54int __vfs_setxattr_noperm(struct dentry *, const char *, const void *, size_t, int);
  55int vfs_setxattr(struct dentry *, const char *, const void *, size_t, int);
  56int __vfs_removexattr(struct dentry *, const char *);
  57int vfs_removexattr(struct dentry *, const char *);
  58
  59ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size);
  60ssize_t vfs_getxattr_alloc(struct dentry *dentry, const char *name,
  61                           char **xattr_value, size_t size, gfp_t flags);
  62
  63static inline const char *xattr_prefix(const struct xattr_handler *handler)
  64{
  65        return handler->prefix ?: handler->name;
  66}
  67
  68struct simple_xattrs {
  69        struct list_head head;
  70        spinlock_t lock;
  71};
  72
  73struct simple_xattr {
  74        struct list_head list;
  75        char *name;
  76        size_t size;
  77        char value[0];
  78};
  79
  80/*
  81 * initialize the simple_xattrs structure
  82 */
  83static inline void simple_xattrs_init(struct simple_xattrs *xattrs)
  84{
  85        INIT_LIST_HEAD(&xattrs->head);
  86        spin_lock_init(&xattrs->lock);
  87}
  88
  89/*
  90 * free all the xattrs
  91 */
  92static inline void simple_xattrs_free(struct simple_xattrs *xattrs)
  93{
  94        struct simple_xattr *xattr, *node;
  95
  96        list_for_each_entry_safe(xattr, node, &xattrs->head, list) {
  97                kfree(xattr->name);
  98                kfree(xattr);
  99        }
 100}
 101
 102struct simple_xattr *simple_xattr_alloc(const void *value, size_t size);
 103int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
 104                     void *buffer, size_t size);
 105int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
 106                     const void *value, size_t size, int flags);
 107ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, char *buffer,
 108                          size_t size);
 109void simple_xattr_list_add(struct simple_xattrs *xattrs,
 110                           struct simple_xattr *new_xattr);
 111
 112#endif  /* _LINUX_XATTR_H */
 113