fs/ext4/xattr_user.c

   1 /*
   2  * linux/fs/ext4/xattr_user.c
   3  * Handler for extended user attributes.
   4  *
   5  * Copyright (C) 2001 by Andreas Gruenbacher, <a.gruenbacher@computer.org>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/string.h>
  10 #include <linux/fs.h>
  11 #include "ext4_jbd2.h"
  12 #include "ext4.h"
  13 #include "xattr.h"
  14
  15 static size_t
  16 ext4_xattr_user_list(struct dentry *dentry, char *list, size_t list_size,
  17                      const char *name, size_t name_len, int type)
  18 {
  19         const size_t prefix_len = XATTR_USER_PREFIX_LEN;
  20         const size_t total_len = prefix_len + name_len + 1;
  21
  22         if (!test_opt(dentry->d_sb, XATTR_USER))
  23                 return 0;
  24
  25         if (list && total_len <= list_size) {
  26                 memcpy(list, XATTR_USER_PREFIX, prefix_len);
  27                 memcpy(list+prefix_len, name, name_len);
  28                 list[prefix_len + name_len] = '\0';
  29         }
  30         return total_len;
  31 }
  32
  33 static int
  34 ext4_xattr_user_get(struct dentry *dentry, const char *name,
  35                     void *buffer, size_t size, int type)
  36 {
  37         if (strcmp(name, "") == 0)
  38                 return -EINVAL;
  39         if (!test_opt(dentry->d_sb, XATTR_USER))
  40                 return -EOPNOTSUPP;
  41         return ext4_xattr_get(dentry->d_inode, EXT4_XATTR_INDEX_USER,
  42                               name, buffer, size);
  43 }
  44
  45 static int
  46 ext4_xattr_user_set(struct dentry *dentry, const char *name,
  47                     const void *value, size_t size, int flags, int type)
  48 {
  49         if (strcmp(name, "") == 0)
  50                 return -EINVAL;
  51         if (!test_opt(dentry->d_sb, XATTR_USER))
  52                 return -EOPNOTSUPP;
  53         return ext4_xattr_set(dentry->d_inode, EXT4_XATTR_INDEX_USER,
  54                               name, value, size, flags);
  55 }
  56
  57 const struct xattr_handler ext4_xattr_user_handler = {
  58         .prefix = XATTR_USER_PREFIX,
  59         .list   = ext4_xattr_user_list,
  60         .get    = ext4_xattr_user_get,
  61         .set    = ext4_xattr_user_set,
  62 };