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 xattr_getsecurity(struct inode *, const char *, void *, size_t);
  50 ssize_t __vfs_getxattr(struct dentry *, struct inode *, const char *, void *, size_t);
  51 ssize_t vfs_getxattr(struct dentry *, const char *, void *, size_t);
  52 ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);
  53 int __vfs_setxattr(struct dentry *, struct inode *, const char *, const void *, size_t, int);
  54 int __vfs_setxattr_noperm(struct dentry *, const char *, const void *, size_t, int);
  55 int vfs_setxattr(struct dentry *, const char *, const void *, size_t, int);
  56 int __vfs_removexattr(struct dentry *, const char *);
  57 int __vfs_removexattr_noperm(struct dentry *dentry, const char *name);
  58 int vfs_removexattr(struct dentry *, const char *);
  59
  60 ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size);
  61 ssize_t vfs_getxattr_alloc(struct dentry *dentry, const char *name,
  62                            char **xattr_value, size_t size, gfp_t flags);
  63
  64 static inline const char *xattr_prefix(const struct xattr_handler *handler)
  65 {
  66         return handler->prefix ?: handler->name;
  67 }
  68
  69 struct simple_xattrs {
  70         struct list_head head;
  71         spinlock_t lock;
  72 };
  73
  74 struct simple_xattr {
  75         struct list_head list;
  76         char *name;
  77         size_t size;
  78         char value[0];
  79 };
  80
  81 /*
  82  * initialize the simple_xattrs structure
  83  */
  84 static inline void simple_xattrs_init(struct simple_xattrs *xattrs)
  85 {
  86         INIT_LIST_HEAD(&xattrs->head);
  87         spin_lock_init(&xattrs->lock);
  88 }
  89
  90 /*
  91  * free all the xattrs
  92  */
  93 static inline void simple_xattrs_free(struct simple_xattrs *xattrs)
  94 {
  95         struct simple_xattr *xattr, *node;
  96
  97         list_for_each_entry_safe(xattr, node, &xattrs->head, list) {
  98                 kfree(xattr->name);
  99                 kfree(xattr);
 100         }
 101 }
 102
 103 struct simple_xattr *simple_xattr_alloc(const void *value, size_t size);
 104 int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
 105                      void *buffer, size_t size);
 106 int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
 107                      const void *value, size_t size, int flags);
 108 ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, char *buffer,
 109                           size_t size);
 110 void simple_xattr_list_add(struct simple_xattrs *xattrs,
 111                            struct simple_xattr *new_xattr);
 112
 113 #endif  /* _LINUX_XATTR_H */