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, | |
32 | .show_options = generic_show_options, | |
33 | }; | |
34 | ||
35 | static 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 | */ | |
6fa67e70 | 48 | static int efivarfs_d_compare(const struct dentry *dentry, |
d68772b7 MF |
49 | unsigned int len, const char *str, |
50 | const struct qstr *name) | |
51 | { | |
52 | int guid = len - EFI_VARIABLE_GUID_LEN; | |
53 | ||
54 | if (name->len != len) | |
55 | return 1; | |
56 | ||
57 | /* Case-sensitive compare for the variable name */ | |
58 | if (memcmp(str, name->name, guid)) | |
59 | return 1; | |
60 | ||
61 | /* Case-insensitive compare for the GUID */ | |
62 | return strncasecmp(name->name + guid, str + guid, EFI_VARIABLE_GUID_LEN); | |
63 | } | |
64 | ||
da53be12 | 65 | static int efivarfs_d_hash(const struct dentry *dentry, struct qstr *qstr) |
d68772b7 | 66 | { |
8387ff25 | 67 | unsigned long hash = init_name_hash(dentry); |
d68772b7 MF |
68 | const unsigned char *s = qstr->name; |
69 | unsigned int len = qstr->len; | |
70 | ||
71 | if (!efivarfs_valid_name(s, len)) | |
72 | return -EINVAL; | |
73 | ||
74 | while (len-- > EFI_VARIABLE_GUID_LEN) | |
75 | hash = partial_name_hash(*s++, hash); | |
76 | ||
77 | /* GUID is case-insensitive. */ | |
78 | while (len--) | |
79 | hash = partial_name_hash(tolower(*s++), hash); | |
80 | ||
81 | qstr->hash = end_name_hash(hash); | |
82 | return 0; | |
83 | } | |
84 | ||
e37dcbfb | 85 | static const struct dentry_operations efivarfs_d_ops = { |
d68772b7 MF |
86 | .d_compare = efivarfs_d_compare, |
87 | .d_hash = efivarfs_d_hash, | |
b26d4cd3 | 88 | .d_delete = always_delete_dentry, |
d68772b7 MF |
89 | }; |
90 | ||
91 | static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name) | |
92 | { | |
93 | struct dentry *d; | |
94 | struct qstr q; | |
95 | int err; | |
96 | ||
97 | q.name = name; | |
98 | q.len = strlen(name); | |
99 | ||
8387ff25 | 100 | err = efivarfs_d_hash(parent, &q); |
d68772b7 MF |
101 | if (err) |
102 | return ERR_PTR(err); | |
103 | ||
104 | d = d_alloc(parent, &q); | |
105 | if (d) | |
106 | return d; | |
107 | ||
108 | return ERR_PTR(-ENOMEM); | |
109 | } | |
110 | ||
111 | static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor, | |
112 | unsigned long name_size, void *data) | |
113 | { | |
114 | struct super_block *sb = (struct super_block *)data; | |
115 | struct efivar_entry *entry; | |
116 | struct inode *inode = NULL; | |
117 | struct dentry *dentry, *root = sb->s_root; | |
118 | unsigned long size = 0; | |
119 | char *name; | |
e0d64e6a | 120 | int len; |
d68772b7 | 121 | int err = -ENOMEM; |
ed8b0de5 | 122 | bool is_removable = false; |
d68772b7 | 123 | |
c57dcb56 | 124 | entry = kzalloc(sizeof(*entry), GFP_KERNEL); |
d68772b7 MF |
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 | ||
e0d64e6a | 131 | len = ucs2_utf8size(entry->var.VariableName); |
d68772b7 MF |
132 | |
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 | ||
e0d64e6a | 138 | ucs2_as_utf8(name, entry->var.VariableName, len); |
d68772b7 | 139 | |
ed8b0de5 PJ |
140 | if (efivar_variable_is_removable(entry->var.VendorGuid, name, len)) |
141 | is_removable = true; | |
142 | ||
d68772b7 MF |
143 | name[len] = '-'; |
144 | ||
26e02272 | 145 | efi_guid_to_str(&entry->var.VendorGuid, name + len + 1); |
d68772b7 MF |
146 | |
147 | name[len + EFI_VARIABLE_GUID_LEN+1] = '\0'; | |
148 | ||
ed8b0de5 PJ |
149 | inode = efivarfs_get_inode(sb, d_inode(root), S_IFREG | 0644, 0, |
150 | is_removable); | |
d68772b7 MF |
151 | if (!inode) |
152 | goto fail_name; | |
153 | ||
154 | dentry = efivarfs_alloc_dentry(root, name); | |
155 | if (IS_ERR(dentry)) { | |
156 | err = PTR_ERR(dentry); | |
157 | goto fail_inode; | |
158 | } | |
159 | ||
d68772b7 | 160 | efivar_entry_size(entry, &size); |
21b3ddd3 SC |
161 | err = efivar_entry_add(entry, &efivarfs_list); |
162 | if (err) | |
163 | goto fail_inode; | |
d68772b7 | 164 | |
22c2b77f MF |
165 | /* copied by the above to local storage in the dentry. */ |
166 | kfree(name); | |
167 | ||
5955102c | 168 | inode_lock(inode); |
d68772b7 MF |
169 | inode->i_private = entry; |
170 | i_size_write(inode, size + sizeof(entry->var.Attributes)); | |
5955102c | 171 | inode_unlock(inode); |
d68772b7 MF |
172 | d_add(dentry, inode); |
173 | ||
174 | return 0; | |
175 | ||
176 | fail_inode: | |
177 | iput(inode); | |
178 | fail_name: | |
179 | kfree(name); | |
180 | fail: | |
181 | kfree(entry); | |
182 | return err; | |
183 | } | |
184 | ||
185 | static int efivarfs_destroy(struct efivar_entry *entry, void *data) | |
186 | { | |
21b3ddd3 SC |
187 | int err = efivar_entry_remove(entry); |
188 | ||
189 | if (err) | |
190 | return err; | |
d68772b7 MF |
191 | kfree(entry); |
192 | return 0; | |
193 | } | |
194 | ||
195 | static int efivarfs_fill_super(struct super_block *sb, void *data, int silent) | |
196 | { | |
197 | struct inode *inode = NULL; | |
198 | struct dentry *root; | |
199 | int err; | |
200 | ||
201 | efivarfs_sb = sb; | |
202 | ||
203 | sb->s_maxbytes = MAX_LFS_FILESIZE; | |
09cbfeaf KS |
204 | sb->s_blocksize = PAGE_SIZE; |
205 | sb->s_blocksize_bits = PAGE_SHIFT; | |
d68772b7 MF |
206 | sb->s_magic = EFIVARFS_MAGIC; |
207 | sb->s_op = &efivarfs_ops; | |
208 | sb->s_d_op = &efivarfs_d_ops; | |
209 | sb->s_time_gran = 1; | |
210 | ||
ed8b0de5 | 211 | inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0, true); |
d68772b7 MF |
212 | if (!inode) |
213 | return -ENOMEM; | |
214 | inode->i_op = &efivarfs_dir_inode_operations; | |
215 | ||
216 | root = d_make_root(inode); | |
217 | sb->s_root = root; | |
218 | if (!root) | |
219 | return -ENOMEM; | |
220 | ||
221 | INIT_LIST_HEAD(&efivarfs_list); | |
222 | ||
1cfd6316 | 223 | err = efivar_init(efivarfs_callback, (void *)sb, true, &efivarfs_list); |
d68772b7 MF |
224 | if (err) |
225 | __efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL); | |
226 | ||
227 | return err; | |
228 | } | |
229 | ||
230 | static struct dentry *efivarfs_mount(struct file_system_type *fs_type, | |
231 | int flags, const char *dev_name, void *data) | |
232 | { | |
233 | return mount_single(fs_type, flags, data, efivarfs_fill_super); | |
234 | } | |
235 | ||
236 | static void efivarfs_kill_sb(struct super_block *sb) | |
237 | { | |
238 | kill_litter_super(sb); | |
239 | efivarfs_sb = NULL; | |
240 | ||
241 | /* Remove all entries and destroy */ | |
242 | __efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL); | |
243 | } | |
244 | ||
245 | static struct file_system_type efivarfs_type = { | |
af5a29ae | 246 | .owner = THIS_MODULE, |
d68772b7 MF |
247 | .name = "efivarfs", |
248 | .mount = efivarfs_mount, | |
249 | .kill_sb = efivarfs_kill_sb, | |
250 | }; | |
251 | ||
252 | static __init int efivarfs_init(void) | |
253 | { | |
254 | if (!efi_enabled(EFI_RUNTIME_SERVICES)) | |
af5a29ae | 255 | return -ENODEV; |
d68772b7 MF |
256 | |
257 | if (!efivars_kobject()) | |
af5a29ae | 258 | return -ENODEV; |
d68772b7 MF |
259 | |
260 | return register_filesystem(&efivarfs_type); | |
261 | } | |
262 | ||
af5a29ae MK |
263 | static __exit void efivarfs_exit(void) |
264 | { | |
265 | unregister_filesystem(&efivarfs_type); | |
266 | } | |
267 | ||
d68772b7 MF |
268 | MODULE_AUTHOR("Matthew Garrett, Jeremy Kerr"); |
269 | MODULE_DESCRIPTION("EFI Variable Filesystem"); | |
270 | MODULE_LICENSE("GPL"); | |
271 | MODULE_ALIAS_FS("efivarfs"); | |
272 | ||
273 | module_init(efivarfs_init); | |
af5a29ae | 274 | module_exit(efivarfs_exit); |