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
  20 struct inode;
  21 struct 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  */
  28 struct 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
  41 const char *xattr_full_name(const struct xattr_handler *, const char *);
  42
  43 struct xattr {
  44         const char *name;
  45         void *value;
  46         size_t value_len;
  47 };
  48
  49 ssize_t __vfs_getxattr(struct dentry *, struct inode *, const char *, void *, size_t);
  50 ssize_t vfs_getxattr(struct dentry *, const char *, void *, size_t);
  51 ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);
  52 int __vfs_setxattr(struct dentry *, struct inode *, const char *, const void *, size_t, int);
  53 int __vfs_setxattr_noperm(struct dentry *, const char *, const void *, size_t, int);
  54 int vfs_setxattr(struct dentry *, const char *, const void *, size_t, int);
  55 int __vfs_removexattr(struct dentry *, const char *);
  56 int vfs_removexattr(struct dentry *, const char *);
  57
  58 ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size);
  59 ssize_t vfs_getxattr_alloc(struct dentry *dentry, const char *name,
  60                            char **xattr_value, size_t size, gfp_t flags);
  61
  62 static inline const char *xattr_prefix(const struct xattr_handler *handler)
  63 {
  64         return handler->prefix ?: handler->name;
  65 }
  66
  67 struct simple_xattrs {
  68         struct list_head head;
  69         spinlock_t lock;
  70 };
  71
  72 struct simple_xattr {
  73         struct list_head list;
  74         char *name;
  75         size_t size;
  76         char value[0];
  77 };
  78
  79 /*
  80  * initialize the simple_xattrs structure
  81  */
  82 static inline void simple_xattrs_init(struct simple_xattrs *xattrs)
  83 {
  84         INIT_LIST_HEAD(&xattrs->head);
  85         spin_lock_init(&xattrs->lock);
  86 }
  87
  88 /*
  89  * free all the xattrs
  90  */
  91 static inline void simple_xattrs_free(struct simple_xattrs *xattrs)
  92 {
  93         struct simple_xattr *xattr, *node;
  94
  95         list_for_each_entry_safe(xattr, node, &xattrs->head, list) {
  96                 kfree(xattr->name);
  97                 kfree(xattr);
  98         }
  99 }
 100
 101 struct simple_xattr *simple_xattr_alloc(const void *value, size_t size);
 102 int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
 103                      void *buffer, size_t size);
 104 int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
 105                      const void *value, size_t size, int flags);
 106 ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, char *buffer,
 107                           size_t size);
 108 void simple_xattr_list_add(struct simple_xattrs *xattrs,
 109                            struct simple_xattr *new_xattr);
 110
 111 #endif  /* _LINUX_XATTR_H */