fs/ext2/xattr_user.c

   1 /*
   2  * linux/fs/ext2/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/init.h>
   9 #include <linux/module.h>
  10 #include <linux/string.h>
  11 #include "ext2.h"
  12 #include "xattr.h"
  13
  14 #define XATTR_USER_PREFIX "user."
  15
  16 static size_t
  17 ext2_xattr_user_list(struct inode *inode, char *list, size_t list_size,
  18                      const char *name, size_t name_len)
  19 {
  20         const size_t prefix_len = sizeof(XATTR_USER_PREFIX)-1;
  21         const size_t total_len = prefix_len + name_len + 1;
  22
  23         if (!test_opt(inode->i_sb, XATTR_USER))
  24                 return 0;
  25
  26         if (list && total_len <= list_size) {
  27                 memcpy(list, XATTR_USER_PREFIX, prefix_len);
  28                 memcpy(list+prefix_len, name, name_len);
  29                 list[prefix_len + name_len] = '\0';
  30         }
  31         return total_len;
  32 }
  33
  34 static int
  35 ext2_xattr_user_get(struct inode *inode, const char *name,
  36                     void *buffer, size_t size)
  37 {
  38         int error;
  39
  40         if (strcmp(name, "") == 0)
  41                 return -EINVAL;
  42         if (!test_opt(inode->i_sb, XATTR_USER))
  43                 return -EOPNOTSUPP;
  44         error = permission(inode, MAY_READ, NULL);
  45         if (error)
  46                 return error;
  47
  48         return ext2_xattr_get(inode, EXT2_XATTR_INDEX_USER, name, buffer, size);
  49 }
  50
  51 static int
  52 ext2_xattr_user_set(struct inode *inode, const char *name,
  53                     const void *value, size_t size, int flags)
  54 {
  55         int error;
  56
  57         if (strcmp(name, "") == 0)
  58                 return -EINVAL;
  59         if (!test_opt(inode->i_sb, XATTR_USER))
  60                 return -EOPNOTSUPP;
  61         if ( !S_ISREG(inode->i_mode) &&
  62             (!S_ISDIR(inode->i_mode) || inode->i_mode & S_ISVTX))
  63                 return -EPERM;
  64         error = permission(inode, MAY_WRITE, NULL);
  65         if (error)
  66                 return error;
  67
  68         return ext2_xattr_set(inode, EXT2_XATTR_INDEX_USER, name,
  69                               value, size, flags);
  70 }
  71
  72 struct xattr_handler ext2_xattr_user_handler = {
  73         .prefix = XATTR_USER_PREFIX,
  74         .list   = ext2_xattr_user_list,
  75         .get    = ext2_xattr_user_get,
  76         .set    = ext2_xattr_user_set,
  77 };