Commit | Line | Data |
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d68772b7 MF |
1 | /* |
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> | |
a614e192 | 15 | #include <linux/ucs2_string.h> |
20b4fb48 LT |
16 | #include <linux/slab.h> |
17 | #include <linux/magic.h> | |
d68772b7 MF |
18 | |
19 | #include "internal.h" | |
20 | ||
21 | LIST_HEAD(efivarfs_list); | |
22 | ||
23 | static void efivarfs_evict_inode(struct inode *inode) | |
24 | { | |
25 | clear_inode(inode); | |
26 | } | |
27 | ||
28 | static const struct super_operations efivarfs_ops = { | |
29 | .statfs = simple_statfs, | |
30 | .drop_inode = generic_delete_inode, | |
31 | .evict_inode = efivarfs_evict_inode, | |
d68772b7 MF |
32 | }; |
33 | ||
34 | static struct super_block *efivarfs_sb; | |
35 | ||
36 | /* | |
37 | * Compare two efivarfs file names. | |
38 | * | |
39 | * An efivarfs filename is composed of two parts, | |
40 | * | |
41 | * 1. A case-sensitive variable name | |
42 | * 2. A case-insensitive GUID | |
43 | * | |
44 | * So we need to perform a case-sensitive match on part 1 and a | |
45 | * case-insensitive match on part 2. | |
46 | */ | |
6fa67e70 | 47 | static int efivarfs_d_compare(const struct dentry *dentry, |
d68772b7 MF |
48 | unsigned int len, const char *str, |
49 | const struct qstr *name) | |
50 | { | |
51 | int guid = len - EFI_VARIABLE_GUID_LEN; | |
52 | ||
53 | if (name->len != len) | |
54 | return 1; | |
55 | ||
56 | /* Case-sensitive compare for the variable name */ | |
57 | if (memcmp(str, name->name, guid)) | |
58 | return 1; | |
59 | ||
60 | /* Case-insensitive compare for the GUID */ | |
61 | return strncasecmp(name->name + guid, str + guid, EFI_VARIABLE_GUID_LEN); | |
62 | } | |
63 | ||
da53be12 | 64 | static int efivarfs_d_hash(const struct dentry *dentry, struct qstr *qstr) |
d68772b7 | 65 | { |
8387ff25 | 66 | unsigned long hash = init_name_hash(dentry); |
d68772b7 MF |
67 | const unsigned char *s = qstr->name; |
68 | unsigned int len = qstr->len; | |
69 | ||
70 | if (!efivarfs_valid_name(s, len)) | |
71 | return -EINVAL; | |
72 | ||
73 | while (len-- > EFI_VARIABLE_GUID_LEN) | |
74 | hash = partial_name_hash(*s++, hash); | |
75 | ||
76 | /* GUID is case-insensitive. */ | |
77 | while (len--) | |
78 | hash = partial_name_hash(tolower(*s++), hash); | |
79 | ||
80 | qstr->hash = end_name_hash(hash); | |
81 | return 0; | |
82 | } | |
83 | ||
e37dcbfb | 84 | static const struct dentry_operations efivarfs_d_ops = { |
d68772b7 MF |
85 | .d_compare = efivarfs_d_compare, |
86 | .d_hash = efivarfs_d_hash, | |
b26d4cd3 | 87 | .d_delete = always_delete_dentry, |
d68772b7 MF |
88 | }; |
89 | ||
90 | static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name) | |
91 | { | |
92 | struct dentry *d; | |
93 | struct qstr q; | |
94 | int err; | |
95 | ||
96 | q.name = name; | |
97 | q.len = strlen(name); | |
98 | ||
8387ff25 | 99 | err = efivarfs_d_hash(parent, &q); |
d68772b7 MF |
100 | if (err) |
101 | return ERR_PTR(err); | |
102 | ||
103 | d = d_alloc(parent, &q); | |
104 | if (d) | |
105 | return d; | |
106 | ||
107 | return ERR_PTR(-ENOMEM); | |
108 | } | |
109 | ||
110 | static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor, | |
111 | unsigned long name_size, void *data) | |
112 | { | |
113 | struct super_block *sb = (struct super_block *)data; | |
114 | struct efivar_entry *entry; | |
115 | struct inode *inode = NULL; | |
116 | struct dentry *dentry, *root = sb->s_root; | |
117 | unsigned long size = 0; | |
118 | char *name; | |
e0d64e6a | 119 | int len; |
d68772b7 | 120 | int err = -ENOMEM; |
ed8b0de5 | 121 | bool is_removable = false; |
d68772b7 | 122 | |
c57dcb56 | 123 | entry = kzalloc(sizeof(*entry), GFP_KERNEL); |
d68772b7 MF |
124 | if (!entry) |
125 | return err; | |
126 | ||
127 | memcpy(entry->var.VariableName, name16, name_size); | |
128 | memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t)); | |
129 | ||
e0d64e6a | 130 | len = ucs2_utf8size(entry->var.VariableName); |
d68772b7 MF |
131 | |
132 | /* name, plus '-', plus GUID, plus NUL*/ | |
133 | name = kmalloc(len + 1 + EFI_VARIABLE_GUID_LEN + 1, GFP_KERNEL); | |
134 | if (!name) | |
135 | goto fail; | |
136 | ||
e0d64e6a | 137 | ucs2_as_utf8(name, entry->var.VariableName, len); |
d68772b7 | 138 | |
ed8b0de5 PJ |
139 | if (efivar_variable_is_removable(entry->var.VendorGuid, name, len)) |
140 | is_removable = true; | |
141 | ||
d68772b7 MF |
142 | name[len] = '-'; |
143 | ||
26e02272 | 144 | efi_guid_to_str(&entry->var.VendorGuid, name + len + 1); |
d68772b7 MF |
145 | |
146 | name[len + EFI_VARIABLE_GUID_LEN+1] = '\0'; | |
147 | ||
ed8b0de5 PJ |
148 | inode = efivarfs_get_inode(sb, d_inode(root), S_IFREG | 0644, 0, |
149 | is_removable); | |
d68772b7 MF |
150 | if (!inode) |
151 | goto fail_name; | |
152 | ||
153 | dentry = efivarfs_alloc_dentry(root, name); | |
154 | if (IS_ERR(dentry)) { | |
155 | err = PTR_ERR(dentry); | |
156 | goto fail_inode; | |
157 | } | |
158 | ||
d68772b7 | 159 | efivar_entry_size(entry, &size); |
21b3ddd3 SC |
160 | err = efivar_entry_add(entry, &efivarfs_list); |
161 | if (err) | |
162 | goto fail_inode; | |
d68772b7 | 163 | |
22c2b77f MF |
164 | /* copied by the above to local storage in the dentry. */ |
165 | kfree(name); | |
166 | ||
5955102c | 167 | inode_lock(inode); |
d68772b7 MF |
168 | inode->i_private = entry; |
169 | i_size_write(inode, size + sizeof(entry->var.Attributes)); | |
5955102c | 170 | inode_unlock(inode); |
d68772b7 MF |
171 | d_add(dentry, inode); |
172 | ||
173 | return 0; | |
174 | ||
175 | fail_inode: | |
176 | iput(inode); | |
177 | fail_name: | |
178 | kfree(name); | |
179 | fail: | |
180 | kfree(entry); | |
181 | return err; | |
182 | } | |
183 | ||
184 | static int efivarfs_destroy(struct efivar_entry *entry, void *data) | |
185 | { | |
21b3ddd3 SC |
186 | int err = efivar_entry_remove(entry); |
187 | ||
188 | if (err) | |
189 | return err; | |
d68772b7 MF |
190 | kfree(entry); |
191 | return 0; | |
192 | } | |
193 | ||
194 | static int efivarfs_fill_super(struct super_block *sb, void *data, int silent) | |
195 | { | |
196 | struct inode *inode = NULL; | |
197 | struct dentry *root; | |
198 | int err; | |
199 | ||
200 | efivarfs_sb = sb; | |
201 | ||
202 | sb->s_maxbytes = MAX_LFS_FILESIZE; | |
09cbfeaf KS |
203 | sb->s_blocksize = PAGE_SIZE; |
204 | sb->s_blocksize_bits = PAGE_SHIFT; | |
d68772b7 MF |
205 | sb->s_magic = EFIVARFS_MAGIC; |
206 | sb->s_op = &efivarfs_ops; | |
207 | sb->s_d_op = &efivarfs_d_ops; | |
208 | sb->s_time_gran = 1; | |
209 | ||
ed8b0de5 | 210 | inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0, true); |
d68772b7 MF |
211 | if (!inode) |
212 | return -ENOMEM; | |
213 | inode->i_op = &efivarfs_dir_inode_operations; | |
214 | ||
215 | root = d_make_root(inode); | |
216 | sb->s_root = root; | |
217 | if (!root) | |
218 | return -ENOMEM; | |
219 | ||
220 | INIT_LIST_HEAD(&efivarfs_list); | |
221 | ||
1cfd6316 | 222 | err = efivar_init(efivarfs_callback, (void *)sb, true, &efivarfs_list); |
d68772b7 MF |
223 | if (err) |
224 | __efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL); | |
225 | ||
226 | return err; | |
227 | } | |
228 | ||
229 | static struct dentry *efivarfs_mount(struct file_system_type *fs_type, | |
230 | int flags, const char *dev_name, void *data) | |
231 | { | |
232 | return mount_single(fs_type, flags, data, efivarfs_fill_super); | |
233 | } | |
234 | ||
235 | static void efivarfs_kill_sb(struct super_block *sb) | |
236 | { | |
237 | kill_litter_super(sb); | |
238 | efivarfs_sb = NULL; | |
239 | ||
240 | /* Remove all entries and destroy */ | |
241 | __efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL); | |
242 | } | |
243 | ||
244 | static struct file_system_type efivarfs_type = { | |
af5a29ae | 245 | .owner = THIS_MODULE, |
d68772b7 MF |
246 | .name = "efivarfs", |
247 | .mount = efivarfs_mount, | |
248 | .kill_sb = efivarfs_kill_sb, | |
249 | }; | |
250 | ||
251 | static __init int efivarfs_init(void) | |
252 | { | |
253 | if (!efi_enabled(EFI_RUNTIME_SERVICES)) | |
af5a29ae | 254 | return -ENODEV; |
d68772b7 MF |
255 | |
256 | if (!efivars_kobject()) | |
af5a29ae | 257 | return -ENODEV; |
d68772b7 MF |
258 | |
259 | return register_filesystem(&efivarfs_type); | |
260 | } | |
261 | ||
af5a29ae MK |
262 | static __exit void efivarfs_exit(void) |
263 | { | |
264 | unregister_filesystem(&efivarfs_type); | |
265 | } | |
266 | ||
d68772b7 MF |
267 | MODULE_AUTHOR("Matthew Garrett, Jeremy Kerr"); |
268 | MODULE_DESCRIPTION("EFI Variable Filesystem"); | |
269 | MODULE_LICENSE("GPL"); | |
270 | MODULE_ALIAS_FS("efivarfs"); | |
271 | ||
272 | module_init(efivarfs_init); | |
af5a29ae | 273 | module_exit(efivarfs_exit); |