2 * Copyright (C) 2012 Red Hat, Inc.
3 * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
10 #include <linux/efi.h>
12 #include <linux/ctype.h>
13 #include <linux/slab.h>
17 struct inode *efivarfs_get_inode(struct super_block *sb,
18 const struct inode *dir, int mode, dev_t dev)
20 struct inode *inode = new_inode(sb);
23 inode->i_ino = get_next_ino();
25 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
26 switch (mode & S_IFMT) {
28 inode->i_fop = &efivarfs_file_operations;
31 inode->i_op = &efivarfs_dir_inode_operations;
32 inode->i_fop = &simple_dir_operations;
41 * Return true if 'str' is a valid efivarfs filename of the form,
43 * VariableName-12345678-1234-1234-1234-1234567891bc
45 bool efivarfs_valid_name(const char *str, int len)
47 static const char dashes[EFI_VARIABLE_GUID_LEN] = {
48 [8] = 1, [13] = 1, [18] = 1, [23] = 1
50 const char *s = str + len - EFI_VARIABLE_GUID_LEN;
54 * We need a GUID, plus at least one letter for the variable name,
55 * plus the '-' separator
57 if (len < EFI_VARIABLE_GUID_LEN + 2)
60 /* GUID must be preceded by a '-' */
65 * Validate that 's' is of the correct format, e.g.
67 * 12345678-1234-1234-1234-123456789abc
69 for (i = 0; i < EFI_VARIABLE_GUID_LEN; i++) {
82 static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
84 guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
85 guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]);
86 guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]);
87 guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]);
88 guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]);
89 guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]);
90 guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]);
91 guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]);
92 guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]);
93 guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]);
94 guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]);
95 guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]);
96 guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]);
97 guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]);
98 guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]);
99 guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]);
102 static int efivarfs_create(struct inode *dir, struct dentry *dentry,
103 umode_t mode, bool excl)
106 struct efivar_entry *var;
107 int namelen, i = 0, err = 0;
109 if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
112 inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
116 var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
122 /* length of the variable name itself: remove GUID and separator */
123 namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1;
125 efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1,
126 &var->var.VendorGuid);
128 for (i = 0; i < namelen; i++)
129 var->var.VariableName[i] = dentry->d_name.name[i];
131 var->var.VariableName[i] = '\0';
133 inode->i_private = var;
135 efivar_entry_add(var, &efivarfs_list);
136 d_instantiate(dentry, inode);
146 static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
148 struct efivar_entry *var = dentry->d_inode->i_private;
150 if (efivar_entry_delete(var))
153 drop_nlink(dentry->d_inode);
158 const struct inode_operations efivarfs_dir_inode_operations = {
159 .lookup = simple_lookup,
160 .unlink = efivarfs_unlink,
161 .create = efivarfs_create,