Commit | Line | Data |
---|---|---|
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 | */ | |
da53be12 LT |
48 | static int efivarfs_d_compare(const struct dentry *parent, |
49 | const struct dentry *dentry, | |
d68772b7 MF |
50 | 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 | ||
da53be12 | 66 | static int efivarfs_d_hash(const struct dentry *dentry, struct qstr *qstr) |
d68772b7 MF |
67 | { |
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 | ||
e37dcbfb | 86 | static const struct dentry_operations efivarfs_d_ops = { |
d68772b7 MF |
87 | .d_compare = efivarfs_d_compare, |
88 | .d_hash = efivarfs_d_hash, | |
b26d4cd3 | 89 | .d_delete = always_delete_dentry, |
d68772b7 MF |
90 | }; |
91 | ||
92 | static 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 | ||
da53be12 | 101 | err = efivarfs_d_hash(NULL, &q); |
d68772b7 MF |
102 | 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 | ||
112 | static 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; | |
e0d64e6a | 121 | int len; |
d68772b7 | 122 | int err = -ENOMEM; |
ed8b0de5 | 123 | bool is_removable = false; |
d68772b7 | 124 | |
c57dcb56 | 125 | entry = kzalloc(sizeof(*entry), GFP_KERNEL); |
d68772b7 MF |
126 | if (!entry) |
127 | return err; | |
128 | ||
129 | memcpy(entry->var.VariableName, name16, name_size); | |
130 | memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t)); | |
131 | ||
e0d64e6a | 132 | len = ucs2_utf8size(entry->var.VariableName); |
d68772b7 MF |
133 | |
134 | /* name, plus '-', plus GUID, plus NUL*/ | |
135 | name = kmalloc(len + 1 + EFI_VARIABLE_GUID_LEN + 1, GFP_KERNEL); | |
136 | if (!name) | |
137 | goto fail; | |
138 | ||
e0d64e6a | 139 | ucs2_as_utf8(name, entry->var.VariableName, len); |
d68772b7 | 140 | |
ed8b0de5 PJ |
141 | if (efivar_variable_is_removable(entry->var.VendorGuid, name, len)) |
142 | is_removable = true; | |
143 | ||
d68772b7 MF |
144 | name[len] = '-'; |
145 | ||
26e02272 | 146 | efi_guid_to_str(&entry->var.VendorGuid, name + len + 1); |
d68772b7 MF |
147 | |
148 | name[len + EFI_VARIABLE_GUID_LEN+1] = '\0'; | |
149 | ||
ed8b0de5 PJ |
150 | inode = efivarfs_get_inode(sb, d_inode(root), S_IFREG | 0644, 0, |
151 | is_removable); | |
d68772b7 MF |
152 | if (!inode) |
153 | goto fail_name; | |
154 | ||
155 | dentry = efivarfs_alloc_dentry(root, name); | |
156 | if (IS_ERR(dentry)) { | |
157 | err = PTR_ERR(dentry); | |
158 | goto fail_inode; | |
159 | } | |
160 | ||
161 | /* copied by the above to local storage in the dentry. */ | |
162 | kfree(name); | |
163 | ||
164 | efivar_entry_size(entry, &size); | |
165 | efivar_entry_add(entry, &efivarfs_list); | |
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 | { | |
186 | efivar_entry_remove(entry); | |
187 | kfree(entry); | |
188 | return 0; | |
189 | } | |
190 | ||
191 | static int efivarfs_fill_super(struct super_block *sb, void *data, int silent) | |
192 | { | |
193 | struct inode *inode = NULL; | |
194 | struct dentry *root; | |
195 | int err; | |
196 | ||
197 | efivarfs_sb = sb; | |
198 | ||
199 | sb->s_maxbytes = MAX_LFS_FILESIZE; | |
09cbfeaf KS |
200 | sb->s_blocksize = PAGE_SIZE; |
201 | sb->s_blocksize_bits = PAGE_SHIFT; | |
d68772b7 MF |
202 | sb->s_magic = EFIVARFS_MAGIC; |
203 | sb->s_op = &efivarfs_ops; | |
204 | sb->s_d_op = &efivarfs_d_ops; | |
205 | sb->s_time_gran = 1; | |
206 | ||
ed8b0de5 | 207 | inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0, true); |
d68772b7 MF |
208 | if (!inode) |
209 | return -ENOMEM; | |
210 | inode->i_op = &efivarfs_dir_inode_operations; | |
211 | ||
212 | root = d_make_root(inode); | |
213 | sb->s_root = root; | |
214 | if (!root) | |
215 | return -ENOMEM; | |
216 | ||
217 | INIT_LIST_HEAD(&efivarfs_list); | |
218 | ||
1cfd6316 | 219 | err = efivar_init(efivarfs_callback, (void *)sb, true, &efivarfs_list); |
d68772b7 MF |
220 | if (err) |
221 | __efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL); | |
222 | ||
223 | return err; | |
224 | } | |
225 | ||
226 | static struct dentry *efivarfs_mount(struct file_system_type *fs_type, | |
227 | int flags, const char *dev_name, void *data) | |
228 | { | |
229 | return mount_single(fs_type, flags, data, efivarfs_fill_super); | |
230 | } | |
231 | ||
232 | static void efivarfs_kill_sb(struct super_block *sb) | |
233 | { | |
234 | kill_litter_super(sb); | |
235 | efivarfs_sb = NULL; | |
236 | ||
237 | /* Remove all entries and destroy */ | |
238 | __efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL); | |
239 | } | |
240 | ||
241 | static struct file_system_type efivarfs_type = { | |
af5a29ae | 242 | .owner = THIS_MODULE, |
d68772b7 MF |
243 | .name = "efivarfs", |
244 | .mount = efivarfs_mount, | |
245 | .kill_sb = efivarfs_kill_sb, | |
246 | }; | |
247 | ||
248 | static __init int efivarfs_init(void) | |
249 | { | |
250 | if (!efi_enabled(EFI_RUNTIME_SERVICES)) | |
af5a29ae | 251 | return -ENODEV; |
d68772b7 MF |
252 | |
253 | if (!efivars_kobject()) | |
af5a29ae | 254 | return -ENODEV; |
d68772b7 MF |
255 | |
256 | return register_filesystem(&efivarfs_type); | |
257 | } | |
258 | ||
af5a29ae MK |
259 | static __exit void efivarfs_exit(void) |
260 | { | |
261 | unregister_filesystem(&efivarfs_type); | |
262 | } | |
263 | ||
d68772b7 MF |
264 | MODULE_AUTHOR("Matthew Garrett, Jeremy Kerr"); |
265 | MODULE_DESCRIPTION("EFI Variable Filesystem"); | |
266 | MODULE_LICENSE("GPL"); | |
267 | MODULE_ALIAS_FS("efivarfs"); | |
268 | ||
269 | module_init(efivarfs_init); | |
af5a29ae | 270 | module_exit(efivarfs_exit); |