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 <linux/smp_lock.h>
  12 #include <linux/ext4_jbd.h>
  13 #include <linux/ext4_fs.h>
  14 #include "xattr.h"
  15
  16 #define XATTR_USER_PREFIX "user."
  17
  18 static size_t
  19 ext4_xattr_user_list(struct inode *inode, char *list, size_t list_size,
  20                      const char *name, size_t name_len)
  21 {
  22         const size_t prefix_len = sizeof(XATTR_USER_PREFIX)-1;
  23         const size_t total_len = prefix_len + name_len + 1;
  24
  25         if (!test_opt(inode->i_sb, XATTR_USER))
  26                 return 0;
  27
  28         if (list && total_len <= list_size) {
  29                 memcpy(list, XATTR_USER_PREFIX, prefix_len);
  30                 memcpy(list+prefix_len, name, name_len);
  31                 list[prefix_len + name_len] = '\0';
  32         }
  33         return total_len;
  34 }
  35
  36 static int
  37 ext4_xattr_user_get(struct inode *inode, const char *name,
  38                     void *buffer, size_t size)
  39 {
  40         if (strcmp(name, "") == 0)
  41                 return -EINVAL;
  42         if (!test_opt(inode->i_sb, XATTR_USER))
  43                 return -EOPNOTSUPP;
  44         return ext4_xattr_get(inode, EXT4_XATTR_INDEX_USER, name, buffer, size);
  45 }
  46
  47 static int
  48 ext4_xattr_user_set(struct inode *inode, const char *name,
  49                     const void *value, size_t size, int flags)
  50 {
  51         if (strcmp(name, "") == 0)
  52                 return -EINVAL;
  53         if (!test_opt(inode->i_sb, XATTR_USER))
  54                 return -EOPNOTSUPP;
  55         return ext4_xattr_set(inode, EXT4_XATTR_INDEX_USER, name,
  56                               value, size, flags);
  57 }
  58
  59 struct xattr_handler ext4_xattr_user_handler = {
  60         .prefix = XATTR_USER_PREFIX,
  61         .list   = ext4_xattr_user_list,
  62         .get    = ext4_xattr_user_get,
  63         .set    = ext4_xattr_user_set,
  64 };