include/linux/xattr.h

   1 /*
   2   File: linux/xattr.h
   3
   4   Extended attributes handling.
   5
   6   Copyright (C) 2001 by Andreas Gruenbacher <a.gruenbacher@computer.org>
   7   Copyright (c) 2001-2002 Silicon Graphics, Inc.  All Rights Reserved.
   8   Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
   9 */
  10 #ifndef _LINUX_XATTR_H
  11 #define _LINUX_XATTR_H
  12
  13
  14 #include <linux/slab.h>
  15 #include <linux/types.h>
  16 #include <linux/spinlock.h>
  17 #include <uapi/linux/xattr.h>
  18
  19 struct inode;
  20 struct dentry;
  21
  22 /*
  23  * struct xattr_handler: When @name is set, match attributes with exactly that
  24  * name.  When @prefix is set instead, match attributes with that prefix and
  25  * with a non-empty suffix.
  26  */
  27 struct xattr_handler {
  28         const char *name;
  29         const char *prefix;
  30         int flags;      /* fs private flags */
  31         bool (*list)(struct dentry *dentry);
  32         int (*get)(const struct xattr_handler *, struct dentry *dentry,
  33                    const char *name, void *buffer, size_t size);
  34         int (*set)(const struct xattr_handler *, struct dentry *dentry,
  35                    const char *name, const void *buffer, size_t size,
  36                    int flags);
  37 };
  38
  39 const char *xattr_full_name(const struct xattr_handler *, const char *);
  40
  41 struct xattr {
  42         const char *name;
  43         void *value;
  44         size_t value_len;
  45 };
  46
  47 ssize_t xattr_getsecurity(struct inode *, const char *, void *, size_t);
  48 ssize_t vfs_getxattr(struct dentry *, const char *, void *, size_t);
  49 ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);
  50 int __vfs_setxattr_noperm(struct dentry *, const char *, const void *, size_t, int);
  51 int vfs_setxattr(struct dentry *, const char *, const void *, size_t, int);
  52 int vfs_removexattr(struct dentry *, const char *);
  53
  54 ssize_t generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size);
  55 ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size);
  56 int generic_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags);
  57 int generic_removexattr(struct dentry *dentry, const char *name);
  58 ssize_t vfs_getxattr_alloc(struct dentry *dentry, const char *name,
  59                            char **xattr_value, size_t size, gfp_t flags);
  60
  61 static inline const char *xattr_prefix(const struct xattr_handler *handler)
  62 {
  63         return handler->prefix ?: handler->name;
  64 }
  65
  66 struct simple_xattrs {
  67         struct list_head head;
  68         spinlock_t lock;
  69 };
  70
  71 struct simple_xattr {
  72         struct list_head list;
  73         char *name;
  74         size_t size;
  75         char value[0];
  76 };
  77
  78 /*
  79  * initialize the simple_xattrs structure
  80  */
  81 static inline void simple_xattrs_init(struct simple_xattrs *xattrs)
  82 {
  83         INIT_LIST_HEAD(&xattrs->head);
  84         spin_lock_init(&xattrs->lock);
  85 }
  86
  87 /*
  88  * free all the xattrs
  89  */
  90 static inline void simple_xattrs_free(struct simple_xattrs *xattrs)
  91 {
  92         struct simple_xattr *xattr, *node;
  93
  94         list_for_each_entry_safe(xattr, node, &xattrs->head, list) {
  95                 kfree(xattr->name);
  96                 kfree(xattr);
  97         }
  98 }
  99
 100 struct simple_xattr *simple_xattr_alloc(const void *value, size_t size);
 101 int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
 102                      void *buffer, size_t size);
 103 int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
 104                      const void *value, size_t size, int flags);
 105 ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, char *buffer,
 106                           size_t size);
 107 void simple_xattr_list_add(struct simple_xattrs *xattrs,
 108                            struct simple_xattr *new_xattr);
 109
 110 #endif  /* _LINUX_XATTR_H */