Merge branch 'linus' into irq/core, to pick up fixes
[linux-2.6-block.git] / fs / efivarfs / super.c
... / ...
CommitLineData
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>
15#include <linux/ucs2_string.h>
16#include <linux/slab.h>
17#include <linux/magic.h>
18
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 */
48static int efivarfs_d_compare(const struct dentry *parent,
49 const struct dentry *dentry,
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
66static int efivarfs_d_hash(const struct dentry *dentry, struct qstr *qstr)
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
86static const struct dentry_operations efivarfs_d_ops = {
87 .d_compare = efivarfs_d_compare,
88 .d_hash = efivarfs_d_hash,
89 .d_delete = always_delete_dentry,
90};
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
101 err = efivarfs_d_hash(NULL, &q);
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
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;
122 int err = -ENOMEM;
123 bool is_removable = false;
124
125 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
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
132 len = ucs2_utf8size(entry->var.VariableName);
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
139 ucs2_as_utf8(name, entry->var.VariableName, len);
140
141 if (efivar_variable_is_removable(entry->var.VendorGuid, name, len))
142 is_removable = true;
143
144 name[len] = '-';
145
146 efi_guid_to_str(&entry->var.VendorGuid, name + len + 1);
147
148 name[len + EFI_VARIABLE_GUID_LEN+1] = '\0';
149
150 inode = efivarfs_get_inode(sb, d_inode(root), S_IFREG | 0644, 0,
151 is_removable);
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
167 inode_lock(inode);
168 inode->i_private = entry;
169 i_size_write(inode, size + sizeof(entry->var.Attributes));
170 inode_unlock(inode);
171 d_add(dentry, inode);
172
173 return 0;
174
175fail_inode:
176 iput(inode);
177fail_name:
178 kfree(name);
179fail:
180 kfree(entry);
181 return err;
182}
183
184static int efivarfs_destroy(struct efivar_entry *entry, void *data)
185{
186 efivar_entry_remove(entry);
187 kfree(entry);
188 return 0;
189}
190
191static 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;
200 sb->s_blocksize = PAGE_CACHE_SIZE;
201 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
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
207 inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0, true);
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
219 err = efivar_init(efivarfs_callback, (void *)sb, false,
220 true, &efivarfs_list);
221 if (err)
222 __efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL);
223
224 return err;
225}
226
227static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
228 int flags, const char *dev_name, void *data)
229{
230 return mount_single(fs_type, flags, data, efivarfs_fill_super);
231}
232
233static void efivarfs_kill_sb(struct super_block *sb)
234{
235 kill_litter_super(sb);
236 efivarfs_sb = NULL;
237
238 /* Remove all entries and destroy */
239 __efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL);
240}
241
242static struct file_system_type efivarfs_type = {
243 .owner = THIS_MODULE,
244 .name = "efivarfs",
245 .mount = efivarfs_mount,
246 .kill_sb = efivarfs_kill_sb,
247};
248
249static __init int efivarfs_init(void)
250{
251 if (!efi_enabled(EFI_RUNTIME_SERVICES))
252 return -ENODEV;
253
254 if (!efivars_kobject())
255 return -ENODEV;
256
257 return register_filesystem(&efivarfs_type);
258}
259
260static __exit void efivarfs_exit(void)
261{
262 unregister_filesystem(&efivarfs_type);
263}
264
265MODULE_AUTHOR("Matthew Garrett, Jeremy Kerr");
266MODULE_DESCRIPTION("EFI Variable Filesystem");
267MODULE_LICENSE("GPL");
268MODULE_ALIAS_FS("efivarfs");
269
270module_init(efivarfs_init);
271module_exit(efivarfs_exit);