[linux-2.6-block.git] / fs / efivarfs / super.c

/*
 * Copyright (C) 2012 Red Hat, Inc.
 * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/ctype.h>
#include <linux/efi.h>
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/pagemap.h>
#include <linux/ucs2_string.h>
#include <linux/slab.h>
#include <linux/magic.h>

#include "internal.h"

LIST_HEAD(efivarfs_list);

static void efivarfs_evict_inode(struct inode *inode)
{
	clear_inode(inode);
}

static const struct super_operations efivarfs_ops = {
	.statfs = simple_statfs,
	.drop_inode = generic_delete_inode,
	.evict_inode = efivarfs_evict_inode,
	.show_options = generic_show_options,
};

static struct super_block *efivarfs_sb;

/*
 * Compare two efivarfs file names.
 *
 * An efivarfs filename is composed of two parts,
 *
 *	1. A case-sensitive variable name
 *	2. A case-insensitive GUID
 *
 * So we need to perform a case-sensitive match on part 1 and a
 * case-insensitive match on part 2.
 */
static int efivarfs_d_compare(const struct dentry *parent,
			      const struct dentry *dentry,
			      unsigned int len, const char *str,
			      const struct qstr *name)
{
	int guid = len - EFI_VARIABLE_GUID_LEN;

	if (name->len != len)
		return 1;

	/* Case-sensitive compare for the variable name */
	if (memcmp(str, name->name, guid))
		return 1;

	/* Case-insensitive compare for the GUID */
	return strncasecmp(name->name + guid, str + guid, EFI_VARIABLE_GUID_LEN);
}

static int efivarfs_d_hash(const struct dentry *dentry, struct qstr *qstr)
{
	unsigned long hash = init_name_hash();
	const unsigned char *s = qstr->name;
	unsigned int len = qstr->len;

	if (!efivarfs_valid_name(s, len))
		return -EINVAL;

	while (len-- > EFI_VARIABLE_GUID_LEN)
		hash = partial_name_hash(*s++, hash);

	/* GUID is case-insensitive. */
	while (len--)
		hash = partial_name_hash(tolower(*s++), hash);

	qstr->hash = end_name_hash(hash);
	return 0;
}

static const struct dentry_operations efivarfs_d_ops = {
	.d_compare = efivarfs_d_compare,
	.d_hash = efivarfs_d_hash,
	.d_delete = always_delete_dentry,
};

static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
{
	struct dentry *d;
	struct qstr q;
	int err;

	q.name = name;
	q.len = strlen(name);

	err = efivarfs_d_hash(NULL, &q);
	if (err)
		return ERR_PTR(err);

	d = d_alloc(parent, &q);
	if (d)
		return d;

	return ERR_PTR(-ENOMEM);
}

static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
			     unsigned long name_size, void *data)
{
	struct super_block *sb = (struct super_block *)data;
	struct efivar_entry *entry;
	struct inode *inode = NULL;
	struct dentry *dentry, *root = sb->s_root;
	unsigned long size = 0;
	char *name;
	int len;
	int err = -ENOMEM;
	bool is_removable = false;

	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
	if (!entry)
		return err;

	memcpy(entry->var.VariableName, name16, name_size);
	memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));

	len = ucs2_utf8size(entry->var.VariableName);

	/* name, plus '-', plus GUID, plus NUL*/
	name = kmalloc(len + 1 + EFI_VARIABLE_GUID_LEN + 1, GFP_KERNEL);
	if (!name)
		goto fail;

	ucs2_as_utf8(name, entry->var.VariableName, len);

	if (efivar_variable_is_removable(entry->var.VendorGuid, name, len))
		is_removable = true;

	name[len] = '-';

	efi_guid_to_str(&entry->var.VendorGuid, name + len + 1);

	name[len + EFI_VARIABLE_GUID_LEN+1] = '\0';

	inode = efivarfs_get_inode(sb, d_inode(root), S_IFREG | 0644, 0,
				   is_removable);
	if (!inode)
		goto fail_name;

	dentry = efivarfs_alloc_dentry(root, name);
	if (IS_ERR(dentry)) {
		err = PTR_ERR(dentry);
		goto fail_inode;
	}

	/* copied by the above to local storage in the dentry. */
	kfree(name);

	efivar_entry_size(entry, &size);
	efivar_entry_add(entry, &efivarfs_list);

	inode_lock(inode);
	inode->i_private = entry;
	i_size_write(inode, size + sizeof(entry->var.Attributes));
	inode_unlock(inode);
	d_add(dentry, inode);

	return 0;

fail_inode:
	iput(inode);
fail_name:
	kfree(name);
fail:
	kfree(entry);
	return err;
}

static int efivarfs_destroy(struct efivar_entry *entry, void *data)
{
	efivar_entry_remove(entry);
	kfree(entry);
	return 0;
}

static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
{
	struct inode *inode = NULL;
	struct dentry *root;
	int err;

	efivarfs_sb = sb;

	sb->s_maxbytes          = MAX_LFS_FILESIZE;
	sb->s_blocksize         = PAGE_CACHE_SIZE;
	sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
	sb->s_magic             = EFIVARFS_MAGIC;
	sb->s_op                = &efivarfs_ops;
	sb->s_d_op		= &efivarfs_d_ops;
	sb->s_time_gran         = 1;

	inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0, true);
	if (!inode)
		return -ENOMEM;
	inode->i_op = &efivarfs_dir_inode_operations;

	root = d_make_root(inode);
	sb->s_root = root;
	if (!root)
		return -ENOMEM;

	INIT_LIST_HEAD(&efivarfs_list);

	err = efivar_init(efivarfs_callback, (void *)sb, false,
			  true, &efivarfs_list);
	if (err)
		__efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL);

	return err;
}

static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
				    int flags, const char *dev_name, void *data)
{
	return mount_single(fs_type, flags, data, efivarfs_fill_super);
}

static void efivarfs_kill_sb(struct super_block *sb)
{
	kill_litter_super(sb);
	efivarfs_sb = NULL;

	/* Remove all entries and destroy */
	__efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL);
}

static struct file_system_type efivarfs_type = {
	.owner   = THIS_MODULE,
	.name    = "efivarfs",
	.mount   = efivarfs_mount,
	.kill_sb = efivarfs_kill_sb,
};

static __init int efivarfs_init(void)
{
	if (!efi_enabled(EFI_RUNTIME_SERVICES))
		return -ENODEV;

	if (!efivars_kobject())
		return -ENODEV;

	return register_filesystem(&efivarfs_type);
}

static __exit void efivarfs_exit(void)
{
	unregister_filesystem(&efivarfs_type);
}

MODULE_AUTHOR("Matthew Garrett, Jeremy Kerr");
MODULE_DESCRIPTION("EFI Variable Filesystem");
MODULE_LICENSE("GPL");
MODULE_ALIAS_FS("efivarfs");

module_init(efivarfs_init);
module_exit(efivarfs_exit);
Commit	Line	Data
	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
	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	*/
	48	static 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
	66	static 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
	86	static 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
	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
	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
	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;
	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
	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;
	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
	227	static 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
	233	static 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
	242	static 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
	249	static __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
	260	static __exit void efivarfs_exit(void)
	261	{
	262	unregister_filesystem(&efivarfs_type);
	263	}
	264
	265	MODULE_AUTHOR("Matthew Garrett, Jeremy Kerr");
	266	MODULE_DESCRIPTION("EFI Variable Filesystem");
	267	MODULE_LICENSE("GPL");
	268	MODULE_ALIAS_FS("efivarfs");
	269
	270	module_init(efivarfs_init);
	271	module_exit(efivarfs_exit);