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 <linux/mm.h>
  19#include <linux/user_namespace.h>
  20#include <uapi/linux/xattr.h>
  21
  22struct inode;
  23struct dentry;
  24
  25/*
  26 * struct xattr_handler: When @name is set, match attributes with exactly that
  27 * name.  When @prefix is set instead, match attributes with that prefix and
  28 * with a non-empty suffix.
  29 */
  30struct xattr_handler {
  31        const char *name;
  32        const char *prefix;
  33        int flags;      /* fs private flags */
  34        bool (*list)(struct dentry *dentry);
  35        int (*get)(const struct xattr_handler *, struct dentry *dentry,
  36                   struct inode *inode, const char *name, void *buffer,
  37                   size_t size);
  38        int (*set)(const struct xattr_handler *,
  39                   struct user_namespace *mnt_userns, struct dentry *dentry,
  40                   struct inode *inode, const char *name, const void *buffer,
  41                   size_t size, int flags);
  42};
  43
  44const char *xattr_full_name(const struct xattr_handler *, const char *);
  45
  46struct xattr {
  47        const char *name;
  48        void *value;
  49        size_t value_len;
  50};
  51
  52ssize_t __vfs_getxattr(struct dentry *, struct inode *, const char *, void *, size_t);
  53ssize_t vfs_getxattr(struct user_namespace *, struct dentry *, const char *,
  54                     void *, size_t);
  55ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);
  56int __vfs_setxattr(struct user_namespace *, struct dentry *, struct inode *,
  57                   const char *, const void *, size_t, int);
  58int __vfs_setxattr_noperm(struct user_namespace *, struct dentry *,
  59                          const char *, const void *, size_t, int);
  60int __vfs_setxattr_locked(struct user_namespace *, struct dentry *,
  61                          const char *, const void *, size_t, int,
  62                          struct inode **);
  63int vfs_setxattr(struct user_namespace *, struct dentry *, const char *,
  64                 const void *, size_t, int);
  65int __vfs_removexattr(struct user_namespace *, struct dentry *, const char *);
  66int __vfs_removexattr_locked(struct user_namespace *, struct dentry *,
  67                             const char *, struct inode **);
  68int vfs_removexattr(struct user_namespace *, struct dentry *, const char *);
  69
  70ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size);
  71ssize_t vfs_getxattr_alloc(struct user_namespace *mnt_userns,
  72                           struct dentry *dentry, const char *name,
  73                           char **xattr_value, size_t size, gfp_t flags);
  74
  75int xattr_supported_namespace(struct inode *inode, const char *prefix);
  76
  77static inline const char *xattr_prefix(const struct xattr_handler *handler)
  78{
  79        return handler->prefix ?: handler->name;
  80}
  81
  82struct simple_xattrs {
  83        struct list_head head;
  84        spinlock_t lock;
  85};
  86
  87struct simple_xattr {
  88        struct list_head list;
  89        char *name;
  90        size_t size;
  91        char value[];
  92};
  93
  94/*
  95 * initialize the simple_xattrs structure
  96 */
  97static inline void simple_xattrs_init(struct simple_xattrs *xattrs)
  98{
  99        INIT_LIST_HEAD(&xattrs->head);
 100        spin_lock_init(&xattrs->lock);
 101}
 102
 103/*
 104 * free all the xattrs
 105 */
 106static inline void simple_xattrs_free(struct simple_xattrs *xattrs)
 107{
 108        struct simple_xattr *xattr, *node;
 109
 110        list_for_each_entry_safe(xattr, node, &xattrs->head, list) {
 111                kfree(xattr->name);
 112                kvfree(xattr);
 113        }
 114}
 115
 116struct simple_xattr *simple_xattr_alloc(const void *value, size_t size);
 117int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
 118                     void *buffer, size_t size);
 119int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
 120                     const void *value, size_t size, int flags,
 121                     ssize_t *removed_size);
 122ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, char *buffer,
 123                          size_t size);
 124void simple_xattr_list_add(struct simple_xattrs *xattrs,
 125                           struct simple_xattr *new_xattr);
 126
 127#endif  /* _LINUX_XATTR_H */
 128