[deliverable/linux.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 *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(dentry);
	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(parent, &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_SIZE;
	sb->s_blocksize_bits    = PAGE_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, 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
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>
20b4fb48 LT	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,
d68772b7 MF	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] = '-';
d68772b7 MF	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,
ed8b0de5 PJ	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
	160	/* copied by the above to local storage in the dentry. */
	161	kfree(name);
	162
	163	efivar_entry_size(entry, &size);
	164	efivar_entry_add(entry, &efivarfs_list);
	165
5955102c	166	inode_lock(inode);
d68772b7 MF	167	inode->i_private = entry;
d68772b7 MF	168	i_size_write(inode, size + sizeof(entry->var.Attributes));
5955102c	169	inode_unlock(inode);
d68772b7 MF	170	d_add(dentry, inode);
	171
	172	return 0;
	173
	174	fail_inode:
	175	iput(inode);
	176	fail_name:
	177	kfree(name);
	178	fail:
	179	kfree(entry);
	180	return err;
	181	}
	182
	183	static int efivarfs_destroy(struct efivar_entry entry, void data)
	184	{
	185	efivar_entry_remove(entry);
	186	kfree(entry);
	187	return 0;
	188	}
	189
	190	static int efivarfs_fill_super(struct super_block sb, void data, int silent)
	191	{
	192	struct inode *inode = NULL;
	193	struct dentry *root;
	194	int err;
	195
	196	efivarfs_sb = sb;
	197
	198	sb->s_maxbytes = MAX_LFS_FILESIZE;
09cbfeaf KS	199	sb->s_blocksize = PAGE_SIZE;
09cbfeaf KS	200	sb->s_blocksize_bits = PAGE_SHIFT;
d68772b7 MF	201	sb->s_magic = EFIVARFS_MAGIC;
	202	sb->s_op = &efivarfs_ops;
	203	sb->s_d_op = &efivarfs_d_ops;
	204	sb->s_time_gran = 1;
	205
ed8b0de5	206	inode = efivarfs_get_inode(sb, NULL, S_IFDIR \| 0755, 0, true);
d68772b7 MF	207	if (!inode)
	208	return -ENOMEM;
	209	inode->i_op = &efivarfs_dir_inode_operations;
	210
	211	root = d_make_root(inode);
	212	sb->s_root = root;
	213	if (!root)
	214	return -ENOMEM;
	215
	216	INIT_LIST_HEAD(&efivarfs_list);
	217
1cfd6316	218	err = efivar_init(efivarfs_callback, (void *)sb, true, &efivarfs_list);
d68772b7 MF	219	if (err)
	220	__efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL);
	221
	222	return err;
	223	}
	224
	225	static struct dentry efivarfs_mount(struct file_system_type fs_type,
	226	int flags, const char dev_name, void data)
	227	{
	228	return mount_single(fs_type, flags, data, efivarfs_fill_super);
	229	}
	230
	231	static void efivarfs_kill_sb(struct super_block *sb)
	232	{
	233	kill_litter_super(sb);
	234	efivarfs_sb = NULL;
	235
	236	/* Remove all entries and destroy */
	237	__efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL);
	238	}
	239
	240	static struct file_system_type efivarfs_type = {
af5a29ae	241	.owner = THIS_MODULE,
d68772b7 MF	242	.name = "efivarfs",
	243	.mount = efivarfs_mount,
	244	.kill_sb = efivarfs_kill_sb,
	245	};
	246
	247	static __init int efivarfs_init(void)
	248	{
	249	if (!efi_enabled(EFI_RUNTIME_SERVICES))
af5a29ae	250	return -ENODEV;
d68772b7 MF	251
d68772b7 MF	252	if (!efivars_kobject())
af5a29ae	253	return -ENODEV;
d68772b7 MF	254
	255	return register_filesystem(&efivarfs_type);
	256	}
	257
af5a29ae MK	258	static __exit void efivarfs_exit(void)
	259	{
	260	unregister_filesystem(&efivarfs_type);
	261	}
	262
d68772b7 MF	263	MODULE_AUTHOR("Matthew Garrett, Jeremy Kerr");
	264	MODULE_DESCRIPTION("EFI Variable Filesystem");
	265	MODULE_LICENSE("GPL");
	266	MODULE_ALIAS_FS("efivarfs");
	267
	268	module_init(efivarfs_init);
af5a29ae	269	module_exit(efivarfs_exit);