blob: 0a48886e069cda3b1a309ef077a4e6dcc79490bb [file] [log] [blame]
Matt Flemingd68772b2013-02-08 16:27:24 +00001/*
2 * Copyright (C) 2012 Red Hat, Inc.
3 * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com>
4 *
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.
8 */
9
10#include <linux/ctype.h>
11#include <linux/efi.h>
12#include <linux/fs.h>
13#include <linux/module.h>
14#include <linux/pagemap.h>
Matt Fleminga614e192013-04-30 11:30:24 +010015#include <linux/ucs2_string.h>
Linus Torvalds20b4fb42013-05-01 17:51:54 -070016#include <linux/slab.h>
17#include <linux/magic.h>
Matt Flemingd68772b2013-02-08 16:27:24 +000018
19#include "internal.h"
20
21LIST_HEAD(efivarfs_list);
22
23static void efivarfs_evict_inode(struct inode *inode)
24{
25 clear_inode(inode);
26}
27
28static const struct super_operations efivarfs_ops = {
29 .statfs = simple_statfs,
30 .drop_inode = generic_delete_inode,
31 .evict_inode = efivarfs_evict_inode,
32 .show_options = generic_show_options,
33};
34
35static struct super_block *efivarfs_sb;
36
37/*
38 * Compare two efivarfs file names.
39 *
40 * An efivarfs filename is composed of two parts,
41 *
42 * 1. A case-sensitive variable name
43 * 2. A case-insensitive GUID
44 *
45 * So we need to perform a case-sensitive match on part 1 and a
46 * case-insensitive match on part 2.
47 */
Linus Torvaldsda53be12013-05-21 15:22:44 -070048static int efivarfs_d_compare(const struct dentry *parent,
49 const struct dentry *dentry,
Matt Flemingd68772b2013-02-08 16:27:24 +000050 unsigned int len, const char *str,
51 const struct qstr *name)
52{
53 int guid = len - EFI_VARIABLE_GUID_LEN;
54
55 if (name->len != len)
56 return 1;
57
58 /* Case-sensitive compare for the variable name */
59 if (memcmp(str, name->name, guid))
60 return 1;
61
62 /* Case-insensitive compare for the GUID */
63 return strncasecmp(name->name + guid, str + guid, EFI_VARIABLE_GUID_LEN);
64}
65
Linus Torvaldsda53be12013-05-21 15:22:44 -070066static int efivarfs_d_hash(const struct dentry *dentry, struct qstr *qstr)
Matt Flemingd68772b2013-02-08 16:27:24 +000067{
68 unsigned long hash = init_name_hash();
69 const unsigned char *s = qstr->name;
70 unsigned int len = qstr->len;
71
72 if (!efivarfs_valid_name(s, len))
73 return -EINVAL;
74
75 while (len-- > EFI_VARIABLE_GUID_LEN)
76 hash = partial_name_hash(*s++, hash);
77
78 /* GUID is case-insensitive. */
79 while (len--)
80 hash = partial_name_hash(tolower(*s++), hash);
81
82 qstr->hash = end_name_hash(hash);
83 return 0;
84}
85
Fabian Fredericke37dcbf2014-06-04 16:11:14 -070086static const struct dentry_operations efivarfs_d_ops = {
Matt Flemingd68772b2013-02-08 16:27:24 +000087 .d_compare = efivarfs_d_compare,
88 .d_hash = efivarfs_d_hash,
Al Virob26d4cd2013-10-25 18:47:37 -040089 .d_delete = always_delete_dentry,
Matt Flemingd68772b2013-02-08 16:27:24 +000090};
91
92static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
93{
94 struct dentry *d;
95 struct qstr q;
96 int err;
97
98 q.name = name;
99 q.len = strlen(name);
100
Linus Torvaldsda53be12013-05-21 15:22:44 -0700101 err = efivarfs_d_hash(NULL, &q);
Matt Flemingd68772b2013-02-08 16:27:24 +0000102 if (err)
103 return ERR_PTR(err);
104
105 d = d_alloc(parent, &q);
106 if (d)
107 return d;
108
109 return ERR_PTR(-ENOMEM);
110}
111
112static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
113 unsigned long name_size, void *data)
114{
115 struct super_block *sb = (struct super_block *)data;
116 struct efivar_entry *entry;
117 struct inode *inode = NULL;
118 struct dentry *dentry, *root = sb->s_root;
119 unsigned long size = 0;
120 char *name;
121 int len, i;
122 int err = -ENOMEM;
123
124 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
125 if (!entry)
126 return err;
127
128 memcpy(entry->var.VariableName, name16, name_size);
129 memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
130
Matt Fleminga614e192013-04-30 11:30:24 +0100131 len = ucs2_strlen(entry->var.VariableName);
Matt Flemingd68772b2013-02-08 16:27:24 +0000132
133 /* name, plus '-', plus GUID, plus NUL*/
134 name = kmalloc(len + 1 + EFI_VARIABLE_GUID_LEN + 1, GFP_KERNEL);
135 if (!name)
136 goto fail;
137
138 for (i = 0; i < len; i++)
139 name[i] = entry->var.VariableName[i] & 0xFF;
140
141 name[len] = '-';
142
143 efi_guid_unparse(&entry->var.VendorGuid, name + len + 1);
144
145 name[len + EFI_VARIABLE_GUID_LEN+1] = '\0';
146
147 inode = efivarfs_get_inode(sb, root->d_inode, S_IFREG | 0644, 0);
148 if (!inode)
149 goto fail_name;
150
151 dentry = efivarfs_alloc_dentry(root, name);
152 if (IS_ERR(dentry)) {
153 err = PTR_ERR(dentry);
154 goto fail_inode;
155 }
156
157 /* copied by the above to local storage in the dentry. */
158 kfree(name);
159
160 efivar_entry_size(entry, &size);
161 efivar_entry_add(entry, &efivarfs_list);
162
163 mutex_lock(&inode->i_mutex);
164 inode->i_private = entry;
165 i_size_write(inode, size + sizeof(entry->var.Attributes));
166 mutex_unlock(&inode->i_mutex);
167 d_add(dentry, inode);
168
169 return 0;
170
171fail_inode:
172 iput(inode);
173fail_name:
174 kfree(name);
175fail:
176 kfree(entry);
177 return err;
178}
179
180static int efivarfs_destroy(struct efivar_entry *entry, void *data)
181{
182 efivar_entry_remove(entry);
183 kfree(entry);
184 return 0;
185}
186
187static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
188{
189 struct inode *inode = NULL;
190 struct dentry *root;
191 int err;
192
193 efivarfs_sb = sb;
194
195 sb->s_maxbytes = MAX_LFS_FILESIZE;
196 sb->s_blocksize = PAGE_CACHE_SIZE;
197 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
198 sb->s_magic = EFIVARFS_MAGIC;
199 sb->s_op = &efivarfs_ops;
200 sb->s_d_op = &efivarfs_d_ops;
201 sb->s_time_gran = 1;
202
203 inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0);
204 if (!inode)
205 return -ENOMEM;
206 inode->i_op = &efivarfs_dir_inode_operations;
207
208 root = d_make_root(inode);
209 sb->s_root = root;
210 if (!root)
211 return -ENOMEM;
212
213 INIT_LIST_HEAD(&efivarfs_list);
214
215 err = efivar_init(efivarfs_callback, (void *)sb, false,
216 true, &efivarfs_list);
217 if (err)
218 __efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL);
219
220 return err;
221}
222
223static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
224 int flags, const char *dev_name, void *data)
225{
226 return mount_single(fs_type, flags, data, efivarfs_fill_super);
227}
228
229static void efivarfs_kill_sb(struct super_block *sb)
230{
231 kill_litter_super(sb);
232 efivarfs_sb = NULL;
233
234 /* Remove all entries and destroy */
235 __efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL);
236}
237
238static struct file_system_type efivarfs_type = {
239 .name = "efivarfs",
240 .mount = efivarfs_mount,
241 .kill_sb = efivarfs_kill_sb,
242};
243
244static __init int efivarfs_init(void)
245{
246 if (!efi_enabled(EFI_RUNTIME_SERVICES))
247 return 0;
248
249 if (!efivars_kobject())
250 return 0;
251
252 return register_filesystem(&efivarfs_type);
253}
254
255MODULE_AUTHOR("Matthew Garrett, Jeremy Kerr");
256MODULE_DESCRIPTION("EFI Variable Filesystem");
257MODULE_LICENSE("GPL");
258MODULE_ALIAS_FS("efivarfs");
259
260module_init(efivarfs_init);