2 * Copyright (C) 2012 Red Hat, Inc.
3 * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com>
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.
10 #include <linux/ctype.h>
11 #include <linux/efi.h>
13 #include <linux/module.h>
14 #include <linux/pagemap.h>
18 LIST_HEAD(efivarfs_list);
20 static void efivarfs_evict_inode(struct inode *inode)
25 static const struct super_operations efivarfs_ops = {
26 .statfs = simple_statfs,
27 .drop_inode = generic_delete_inode,
28 .evict_inode = efivarfs_evict_inode,
29 .show_options = generic_show_options,
32 static struct super_block *efivarfs_sb;
35 * Compare two efivarfs file names.
37 * An efivarfs filename is composed of two parts,
39 * 1. A case-sensitive variable name
40 * 2. A case-insensitive GUID
42 * So we need to perform a case-sensitive match on part 1 and a
43 * case-insensitive match on part 2.
45 static int efivarfs_d_compare(const struct dentry *parent, const struct inode *pinode,
46 const struct dentry *dentry, const struct inode *inode,
47 unsigned int len, const char *str,
48 const struct qstr *name)
50 int guid = len - EFI_VARIABLE_GUID_LEN;
55 /* Case-sensitive compare for the variable name */
56 if (memcmp(str, name->name, guid))
59 /* Case-insensitive compare for the GUID */
60 return strncasecmp(name->name + guid, str + guid, EFI_VARIABLE_GUID_LEN);
63 static int efivarfs_d_hash(const struct dentry *dentry,
64 const struct inode *inode, struct qstr *qstr)
66 unsigned long hash = init_name_hash();
67 const unsigned char *s = qstr->name;
68 unsigned int len = qstr->len;
70 if (!efivarfs_valid_name(s, len))
73 while (len-- > EFI_VARIABLE_GUID_LEN)
74 hash = partial_name_hash(*s++, hash);
76 /* GUID is case-insensitive. */
78 hash = partial_name_hash(tolower(*s++), hash);
80 qstr->hash = end_name_hash(hash);
85 * Retaining negative dentries for an in-memory filesystem just wastes
86 * memory and lookup time: arrange for them to be deleted immediately.
88 static int efivarfs_delete_dentry(const struct dentry *dentry)
93 static struct dentry_operations efivarfs_d_ops = {
94 .d_compare = efivarfs_d_compare,
95 .d_hash = efivarfs_d_hash,
96 .d_delete = efivarfs_delete_dentry,
99 static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
106 q.len = strlen(name);
108 err = efivarfs_d_hash(NULL, NULL, &q);
112 d = d_alloc(parent, &q);
116 return ERR_PTR(-ENOMEM);
119 static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
120 unsigned long name_size, void *data)
122 struct super_block *sb = (struct super_block *)data;
123 struct efivar_entry *entry;
124 struct inode *inode = NULL;
125 struct dentry *dentry, *root = sb->s_root;
126 unsigned long size = 0;
131 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
135 memcpy(entry->var.VariableName, name16, name_size);
136 memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
138 len = utf16_strlen(entry->var.VariableName);
140 /* name, plus '-', plus GUID, plus NUL*/
141 name = kmalloc(len + 1 + EFI_VARIABLE_GUID_LEN + 1, GFP_KERNEL);
145 for (i = 0; i < len; i++)
146 name[i] = entry->var.VariableName[i] & 0xFF;
150 efi_guid_unparse(&entry->var.VendorGuid, name + len + 1);
152 name[len + EFI_VARIABLE_GUID_LEN+1] = '\0';
154 inode = efivarfs_get_inode(sb, root->d_inode, S_IFREG | 0644, 0);
158 dentry = efivarfs_alloc_dentry(root, name);
159 if (IS_ERR(dentry)) {
160 err = PTR_ERR(dentry);
164 /* copied by the above to local storage in the dentry. */
167 efivar_entry_size(entry, &size);
168 efivar_entry_add(entry, &efivarfs_list);
170 mutex_lock(&inode->i_mutex);
171 inode->i_private = entry;
172 i_size_write(inode, size + sizeof(entry->var.Attributes));
173 mutex_unlock(&inode->i_mutex);
174 d_add(dentry, inode);
187 static int efivarfs_destroy(struct efivar_entry *entry, void *data)
189 efivar_entry_remove(entry);
194 static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
196 struct inode *inode = NULL;
202 sb->s_maxbytes = MAX_LFS_FILESIZE;
203 sb->s_blocksize = PAGE_CACHE_SIZE;
204 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
205 sb->s_magic = EFIVARFS_MAGIC;
206 sb->s_op = &efivarfs_ops;
207 sb->s_d_op = &efivarfs_d_ops;
210 inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0);
213 inode->i_op = &efivarfs_dir_inode_operations;
215 root = d_make_root(inode);
220 INIT_LIST_HEAD(&efivarfs_list);
222 err = efivar_init(efivarfs_callback, (void *)sb, false,
223 true, &efivarfs_list);
225 __efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL);
230 static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
231 int flags, const char *dev_name, void *data)
233 return mount_single(fs_type, flags, data, efivarfs_fill_super);
236 static void efivarfs_kill_sb(struct super_block *sb)
238 kill_litter_super(sb);
241 /* Remove all entries and destroy */
242 __efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL);
245 static struct file_system_type efivarfs_type = {
247 .mount = efivarfs_mount,
248 .kill_sb = efivarfs_kill_sb,
251 static __init int efivarfs_init(void)
253 if (!efi_enabled(EFI_RUNTIME_SERVICES))
256 if (!efivars_kobject())
259 return register_filesystem(&efivarfs_type);
262 MODULE_AUTHOR("Matthew Garrett, Jeremy Kerr");
263 MODULE_DESCRIPTION("EFI Variable Filesystem");
264 MODULE_LICENSE("GPL");
265 MODULE_ALIAS_FS("efivarfs");
267 module_init(efivarfs_init);