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

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2012 Red Hat, Inc.
 * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com>
 */

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

#include "internal.h"

LIST_HEAD(efivarfs_list);

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

static int efivarfs_show_options(struct seq_file *m, struct dentry *root)
{
	struct super_block *sb = root->d_sb;
	struct efivarfs_fs_info *sbi = sb->s_fs_info;
	struct efivarfs_mount_opts *opts = &sbi->mount_opts;

	if (!uid_eq(opts->uid, GLOBAL_ROOT_UID))
		seq_printf(m, ",uid=%u",
				from_kuid_munged(&init_user_ns, opts->uid));
	if (!gid_eq(opts->gid, GLOBAL_ROOT_GID))
		seq_printf(m, ",gid=%u",
				from_kgid_munged(&init_user_ns, opts->gid));
	return 0;
}

static int efivarfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
	const u32 attr = EFI_VARIABLE_NON_VOLATILE |
			 EFI_VARIABLE_BOOTSERVICE_ACCESS |
			 EFI_VARIABLE_RUNTIME_ACCESS;
	u64 storage_space, remaining_space, max_variable_size;
	u64 id = huge_encode_dev(dentry->d_sb->s_dev);
	efi_status_t status;

	/* Some UEFI firmware does not implement QueryVariableInfo() */
	storage_space = remaining_space = 0;
	if (efi_rt_services_supported(EFI_RT_SUPPORTED_QUERY_VARIABLE_INFO)) {
		status = efivar_query_variable_info(attr, &storage_space,
						    &remaining_space,
						    &max_variable_size);
		if (status != EFI_SUCCESS && status != EFI_UNSUPPORTED)
			pr_warn_ratelimited("query_variable_info() failed: 0x%lx\n",
					    status);
	}

	/*
	 * This is not a normal filesystem, so no point in pretending it has a block
	 * size; we declare f_bsize to 1, so that we can then report the exact value
	 * sent by EFI QueryVariableInfo in f_blocks and f_bfree
	 */
	buf->f_bsize	= 1;
	buf->f_namelen	= NAME_MAX;
	buf->f_blocks	= storage_space;
	buf->f_bfree	= remaining_space;
	buf->f_type	= dentry->d_sb->s_magic;
	buf->f_fsid	= u64_to_fsid(id);

	/*
	 * In f_bavail we declare the free space that the kernel will allow writing
	 * when the storage_paranoia x86 quirk is active. To use more, users
	 * should boot the kernel with efi_no_storage_paranoia.
	 */
	if (remaining_space > efivar_reserved_space())
		buf->f_bavail = remaining_space - efivar_reserved_space();
	else
		buf->f_bavail = 0;

	return 0;
}
static const struct super_operations efivarfs_ops = {
	.statfs = efivarfs_statfs,
	.drop_inode = generic_delete_inode,
	.evict_inode = efivarfs_evict_inode,
	.show_options = efivarfs_show_options,
};

/*
 * 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;

	if (guid_equal(&vendor, &LINUX_EFI_RANDOM_SEED_TABLE_GUID))
		return 0;

	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';

	/* replace invalid slashes like kobject_set_name_vargs does for /sys/firmware/efi/vars. */
	strreplace(name, '/', '!');

	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;
	}

	__efivar_entry_get(entry, NULL, &size, NULL);
	__efivar_entry_add(entry, &efivarfs_list);

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

	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;
}

enum {
	Opt_uid, Opt_gid,
};

static const struct fs_parameter_spec efivarfs_parameters[] = {
	fsparam_u32("uid", Opt_uid),
	fsparam_u32("gid", Opt_gid),
	{},
};

static int efivarfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
	struct efivarfs_fs_info *sbi = fc->s_fs_info;
	struct efivarfs_mount_opts *opts = &sbi->mount_opts;
	struct fs_parse_result result;
	int opt;

	opt = fs_parse(fc, efivarfs_parameters, param, &result);
	if (opt < 0)
		return opt;

	switch (opt) {
	case Opt_uid:
		opts->uid = make_kuid(current_user_ns(), result.uint_32);
		if (!uid_valid(opts->uid))
			return -EINVAL;
		break;
	case Opt_gid:
		opts->gid = make_kgid(current_user_ns(), result.uint_32);
		if (!gid_valid(opts->gid))
			return -EINVAL;
		break;
	default:
		return -EINVAL;
	}

	return 0;
}

static int efivarfs_fill_super(struct super_block *sb, struct fs_context *fc)
{
	struct inode *inode = NULL;
	struct dentry *root;
	int err;

	if (!efivar_is_available())
		return -EOPNOTSUPP;

	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;

	if (!efivar_supports_writes())
		sb->s_flags |= SB_RDONLY;

	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);

	return err;
}

static int efivarfs_get_tree(struct fs_context *fc)
{
	return get_tree_single(fc, efivarfs_fill_super);
}

static const struct fs_context_operations efivarfs_context_ops = {
	.get_tree	= efivarfs_get_tree,
	.parse_param	= efivarfs_parse_param,
};

static int efivarfs_init_fs_context(struct fs_context *fc)
{
	struct efivarfs_fs_info *sfi;

	sfi = kzalloc(sizeof(*sfi), GFP_KERNEL);
	if (!sfi)
		return -ENOMEM;

	sfi->mount_opts.uid = GLOBAL_ROOT_UID;
	sfi->mount_opts.gid = GLOBAL_ROOT_GID;

	fc->s_fs_info = sfi;
	fc->ops = &efivarfs_context_ops;
	return 0;
}

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

	if (!efivar_is_available())
		return;

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

static struct file_system_type efivarfs_type = {
	.owner   = THIS_MODULE,
	.name    = "efivarfs",
	.init_fs_context = efivarfs_init_fs_context,
	.kill_sb = efivarfs_kill_sb,
	.parameters = efivarfs_parameters,
};

static __init int efivarfs_init(void)
{
	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
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
d68772b7 MF	2	/*
	3	* Copyright (C) 2012 Red Hat, Inc.
	4	* Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com>
d68772b7 MF	5	*/
	6
	7	#include <linux/ctype.h>
	8	#include <linux/efi.h>
	9	#include <linux/fs.h>
47999745	10	#include <linux/fs_context.h>
5329aa51	11	#include <linux/fs_parser.h>
d68772b7 MF	12	#include <linux/module.h>
d68772b7 MF	13	#include <linux/pagemap.h>
a614e192	14	#include <linux/ucs2_string.h>
20b4fb48 LT	15	#include <linux/slab.h>
20b4fb48 LT	16	#include <linux/magic.h>
d86ff333	17	#include <linux/statfs.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
5329aa51 JZ	28	static int efivarfs_show_options(struct seq_file m, struct dentry root)
	29	{
	30	struct super_block *sb = root->d_sb;
	31	struct efivarfs_fs_info *sbi = sb->s_fs_info;
	32	struct efivarfs_mount_opts *opts = &sbi->mount_opts;
	33
	34	if (!uid_eq(opts->uid, GLOBAL_ROOT_UID))
	35	seq_printf(m, ",uid=%u",
	36	from_kuid_munged(&init_user_ns, opts->uid));
	37	if (!gid_eq(opts->gid, GLOBAL_ROOT_GID))
	38	seq_printf(m, ",gid=%u",
	39	from_kgid_munged(&init_user_ns, opts->gid));
	40	return 0;
	41	}
	42
d86ff333 AA	43	static int efivarfs_statfs(struct dentry dentry, struct kstatfs buf)
	44	{
	45	const u32 attr = EFI_VARIABLE_NON_VOLATILE \|
	46	EFI_VARIABLE_BOOTSERVICE_ACCESS \|
	47	EFI_VARIABLE_RUNTIME_ACCESS;
	48	u64 storage_space, remaining_space, max_variable_size;
ae62bcb5	49	u64 id = huge_encode_dev(dentry->d_sb->s_dev);
d86ff333 AA	50	efi_status_t status;
d86ff333 AA	51
79b83606 HS	52	/* Some UEFI firmware does not implement QueryVariableInfo() */
	53	storage_space = remaining_space = 0;
	54	if (efi_rt_services_supported(EFI_RT_SUPPORTED_QUERY_VARIABLE_INFO)) {
	55	status = efivar_query_variable_info(attr, &storage_space,
	56	&remaining_space,
	57	&max_variable_size);
	58	if (status != EFI_SUCCESS && status != EFI_UNSUPPORTED)
	59	pr_warn_ratelimited("query_variable_info() failed: 0x%lx\n",
	60	status);
	61	}
d86ff333 AA	62
	63	/*
	64	* This is not a normal filesystem, so no point in pretending it has a block
	65	* size; we declare f_bsize to 1, so that we can then report the exact value
	66	* sent by EFI QueryVariableInfo in f_blocks and f_bfree
	67	*/
	68	buf->f_bsize = 1;
	69	buf->f_namelen = NAME_MAX;
	70	buf->f_blocks = storage_space;
	71	buf->f_bfree = remaining_space;
	72	buf->f_type = dentry->d_sb->s_magic;
ae62bcb5	73	buf->f_fsid = u64_to_fsid(id);
d86ff333 AA	74
	75	/*
	76	* In f_bavail we declare the free space that the kernel will allow writing
	77	* when the storage_paranoia x86 quirk is active. To use more, users
	78	* should boot the kernel with efi_no_storage_paranoia.
	79	*/
	80	if (remaining_space > efivar_reserved_space())
	81	buf->f_bavail = remaining_space - efivar_reserved_space();
	82	else
	83	buf->f_bavail = 0;
	84
	85	return 0;
	86	}
d68772b7	87	static const struct super_operations efivarfs_ops = {
d86ff333	88	.statfs = efivarfs_statfs,
d68772b7 MF	89	.drop_inode = generic_delete_inode,
d68772b7 MF	90	.evict_inode = efivarfs_evict_inode,
5329aa51	91	.show_options = efivarfs_show_options,
d68772b7 MF	92	};
d68772b7 MF	93
d68772b7 MF	94	/*
	95	* Compare two efivarfs file names.
	96	*
	97	* An efivarfs filename is composed of two parts,
	98	*
	99	* 1. A case-sensitive variable name
	100	* 2. A case-insensitive GUID
	101	*
	102	* So we need to perform a case-sensitive match on part 1 and a
	103	* case-insensitive match on part 2.
	104	*/
6fa67e70	105	static int efivarfs_d_compare(const struct dentry *dentry,
d68772b7 MF	106	unsigned int len, const char *str,
	107	const struct qstr *name)
	108	{
	109	int guid = len - EFI_VARIABLE_GUID_LEN;
	110
	111	if (name->len != len)
	112	return 1;
	113
	114	/* Case-sensitive compare for the variable name */
	115	if (memcmp(str, name->name, guid))
	116	return 1;
	117
	118	/* Case-insensitive compare for the GUID */
	119	return strncasecmp(name->name + guid, str + guid, EFI_VARIABLE_GUID_LEN);
	120	}
	121
da53be12	122	static int efivarfs_d_hash(const struct dentry dentry, struct qstr qstr)
d68772b7	123	{
8387ff25	124	unsigned long hash = init_name_hash(dentry);
d68772b7 MF	125	const unsigned char *s = qstr->name;
	126	unsigned int len = qstr->len;
	127
	128	if (!efivarfs_valid_name(s, len))
	129	return -EINVAL;
	130
	131	while (len-- > EFI_VARIABLE_GUID_LEN)
	132	hash = partial_name_hash(*s++, hash);
	133
	134	/* GUID is case-insensitive. */
	135	while (len--)
	136	hash = partial_name_hash(tolower(*s++), hash);
	137
	138	qstr->hash = end_name_hash(hash);
	139	return 0;
	140	}
	141
e37dcbfb	142	static const struct dentry_operations efivarfs_d_ops = {
d68772b7 MF	143	.d_compare = efivarfs_d_compare,
d68772b7 MF	144	.d_hash = efivarfs_d_hash,
b26d4cd3	145	.d_delete = always_delete_dentry,
d68772b7 MF	146	};
	147
	148	static struct dentry efivarfs_alloc_dentry(struct dentry parent, char *name)
	149	{
	150	struct dentry *d;
	151	struct qstr q;
	152	int err;
	153
	154	q.name = name;
	155	q.len = strlen(name);
	156
8387ff25	157	err = efivarfs_d_hash(parent, &q);
d68772b7 MF	158	if (err)
	159	return ERR_PTR(err);
	160
	161	d = d_alloc(parent, &q);
	162	if (d)
	163	return d;
	164
	165	return ERR_PTR(-ENOMEM);
	166	}
	167
	168	static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
	169	unsigned long name_size, void *data)
	170	{
	171	struct super_block sb = (struct super_block )data;
	172	struct efivar_entry *entry;
	173	struct inode *inode = NULL;
	174	struct dentry dentry, root = sb->s_root;
	175	unsigned long size = 0;
	176	char *name;
e0d64e6a	177	int len;
d68772b7	178	int err = -ENOMEM;
ed8b0de5	179	bool is_removable = false;
d68772b7	180
63ffb573 JD	181	if (guid_equal(&vendor, &LINUX_EFI_RANDOM_SEED_TABLE_GUID))
	182	return 0;
	183
c57dcb56	184	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
d68772b7 MF	185	if (!entry)
	186	return err;
	187
	188	memcpy(entry->var.VariableName, name16, name_size);
	189	memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
	190
e0d64e6a	191	len = ucs2_utf8size(entry->var.VariableName);
d68772b7 MF	192
	193	/* name, plus '-', plus GUID, plus NUL*/
	194	name = kmalloc(len + 1 + EFI_VARIABLE_GUID_LEN + 1, GFP_KERNEL);
	195	if (!name)
	196	goto fail;
	197
e0d64e6a	198	ucs2_as_utf8(name, entry->var.VariableName, len);
d68772b7	199
ed8b0de5 PJ	200	if (efivar_variable_is_removable(entry->var.VendorGuid, name, len))
	201	is_removable = true;
	202
d68772b7 MF	203	name[len] = '-';
d68772b7 MF	204
26e02272	205	efi_guid_to_str(&entry->var.VendorGuid, name + len + 1);
d68772b7 MF	206
	207	name[len + EFI_VARIABLE_GUID_LEN+1] = '\0';
	208
336af6a4 MS	209	/* replace invalid slashes like kobject_set_name_vargs does for /sys/firmware/efi/vars. */
	210	strreplace(name, '/', '!');
	211
ed8b0de5 PJ	212	inode = efivarfs_get_inode(sb, d_inode(root), S_IFREG \| 0644, 0,
ed8b0de5 PJ	213	is_removable);
d68772b7 MF	214	if (!inode)
	215	goto fail_name;
	216
	217	dentry = efivarfs_alloc_dentry(root, name);
	218	if (IS_ERR(dentry)) {
	219	err = PTR_ERR(dentry);
	220	goto fail_inode;
	221	}
	222
ec3507b2 AB	223	__efivar_entry_get(entry, NULL, &size, NULL);
ec3507b2 AB	224	__efivar_entry_add(entry, &efivarfs_list);
d68772b7	225
22c2b77f MF	226	/* copied by the above to local storage in the dentry. */
	227	kfree(name);
	228
5955102c	229	inode_lock(inode);
d68772b7 MF	230	inode->i_private = entry;
d68772b7 MF	231	i_size_write(inode, size + sizeof(entry->var.Attributes));
5955102c	232	inode_unlock(inode);
d68772b7 MF	233	d_add(dentry, inode);
	234
	235	return 0;
	236
	237	fail_inode:
	238	iput(inode);
	239	fail_name:
	240	kfree(name);
	241	fail:
	242	kfree(entry);
	243	return err;
	244	}
	245
	246	static int efivarfs_destroy(struct efivar_entry entry, void data)
	247	{
3a75f9f2	248	efivar_entry_remove(entry);
d68772b7 MF	249	kfree(entry);
	250	return 0;
	251	}
	252
5329aa51 JZ	253	enum {
	254	Opt_uid, Opt_gid,
	255	};
	256
	257	static const struct fs_parameter_spec efivarfs_parameters[] = {
	258	fsparam_u32("uid", Opt_uid),
	259	fsparam_u32("gid", Opt_gid),
	260	{},
	261	};
	262
	263	static int efivarfs_parse_param(struct fs_context fc, struct fs_parameter param)
	264	{
	265	struct efivarfs_fs_info *sbi = fc->s_fs_info;
	266	struct efivarfs_mount_opts *opts = &sbi->mount_opts;
	267	struct fs_parse_result result;
	268	int opt;
	269
	270	opt = fs_parse(fc, efivarfs_parameters, param, &result);
	271	if (opt < 0)
	272	return opt;
	273
	274	switch (opt) {
	275	case Opt_uid:
	276	opts->uid = make_kuid(current_user_ns(), result.uint_32);
	277	if (!uid_valid(opts->uid))
	278	return -EINVAL;
	279	break;
	280	case Opt_gid:
	281	opts->gid = make_kgid(current_user_ns(), result.uint_32);
	282	if (!gid_valid(opts->gid))
	283	return -EINVAL;
	284	break;
	285	default:
	286	return -EINVAL;
	287	}
	288
	289	return 0;
	290	}
	291
47999745	292	static int efivarfs_fill_super(struct super_block sb, struct fs_context fc)
d68772b7 MF	293	{
	294	struct inode *inode = NULL;
	295	struct dentry *root;
	296	int err;
	297
301de9a2 JH	298	if (!efivar_is_available())
	299	return -EOPNOTSUPP;
	300
d68772b7	301	sb->s_maxbytes = MAX_LFS_FILESIZE;
09cbfeaf KS	302	sb->s_blocksize = PAGE_SIZE;
09cbfeaf KS	303	sb->s_blocksize_bits = PAGE_SHIFT;
d68772b7 MF	304	sb->s_magic = EFIVARFS_MAGIC;
	305	sb->s_op = &efivarfs_ops;
	306	sb->s_d_op = &efivarfs_d_ops;
	307	sb->s_time_gran = 1;
	308
f88814cc AB	309	if (!efivar_supports_writes())
	310	sb->s_flags \|= SB_RDONLY;
	311
ed8b0de5	312	inode = efivarfs_get_inode(sb, NULL, S_IFDIR \| 0755, 0, true);
d68772b7 MF	313	if (!inode)
	314	return -ENOMEM;
	315	inode->i_op = &efivarfs_dir_inode_operations;
	316
	317	root = d_make_root(inode);
	318	sb->s_root = root;
	319	if (!root)
	320	return -ENOMEM;
	321
	322	INIT_LIST_HEAD(&efivarfs_list);
	323
1cfd6316	324	err = efivar_init(efivarfs_callback, (void *)sb, true, &efivarfs_list);
d68772b7	325	if (err)
3a75f9f2	326	efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL);
d68772b7 MF	327
	328	return err;
	329	}
	330
47999745 DH	331	static int efivarfs_get_tree(struct fs_context *fc)
	332	{
	333	return get_tree_single(fc, efivarfs_fill_super);
	334	}
	335
	336	static const struct fs_context_operations efivarfs_context_ops = {
	337	.get_tree = efivarfs_get_tree,
5329aa51	338	.parse_param = efivarfs_parse_param,
47999745 DH	339	};
	340
	341	static int efivarfs_init_fs_context(struct fs_context *fc)
d68772b7	342	{
5329aa51 JZ	343	struct efivarfs_fs_info *sfi;
	344
	345	sfi = kzalloc(sizeof(*sfi), GFP_KERNEL);
	346	if (!sfi)
	347	return -ENOMEM;
	348
	349	sfi->mount_opts.uid = GLOBAL_ROOT_UID;
	350	sfi->mount_opts.gid = GLOBAL_ROOT_GID;
	351
	352	fc->s_fs_info = sfi;
47999745 DH	353	fc->ops = &efivarfs_context_ops;
47999745 DH	354	return 0;
d68772b7 MF	355	}
	356
	357	static void efivarfs_kill_sb(struct super_block *sb)
	358	{
	359	kill_litter_super(sb);
d68772b7	360
301de9a2 JH	361	if (!efivar_is_available())
	362	return;
	363
d68772b7	364	/* Remove all entries and destroy */
3a75f9f2	365	efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL);
d68772b7 MF	366	}
	367
	368	static struct file_system_type efivarfs_type = {
af5a29ae	369	.owner = THIS_MODULE,
d68772b7	370	.name = "efivarfs",
47999745	371	.init_fs_context = efivarfs_init_fs_context,
d68772b7	372	.kill_sb = efivarfs_kill_sb,
5329aa51	373	.parameters = efivarfs_parameters,
d68772b7 MF	374	};
	375
	376	static __init int efivarfs_init(void)
	377	{
d68772b7 MF	378	return register_filesystem(&efivarfs_type);
	379	}
	380
af5a29ae MK	381	static __exit void efivarfs_exit(void)
	382	{
	383	unregister_filesystem(&efivarfs_type);
	384	}
	385
d68772b7 MF	386	MODULE_AUTHOR("Matthew Garrett, Jeremy Kerr");
	387	MODULE_DESCRIPTION("EFI Variable Filesystem");
	388	MODULE_LICENSE("GPL");
	389	MODULE_ALIAS_FS("efivarfs");
	390
	391	module_init(efivarfs_init);
af5a29ae	392	module_exit(efivarfs_exit);