[linux-2.6-block.git] / fs / efivarfs / file.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/efi.h>
#include <linux/fs.h>
#include <linux/slab.h>

#include "internal.h"

static ssize_t efivarfs_file_write(struct file *file,
		const char __user *userbuf, size_t count, loff_t *ppos)
{
	struct efivar_entry *var = file->private_data;
	void *data;
	u32 attributes;
	struct inode *inode = file->f_mapping->host;
	unsigned long datasize = count - sizeof(attributes);
	ssize_t bytes;
	bool set = false;

	if (count < sizeof(attributes))
		return -EINVAL;

	if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
		return -EFAULT;

	if (attributes & ~(EFI_VARIABLE_MASK))
		return -EINVAL;

	data = memdup_user(userbuf + sizeof(attributes), datasize);
	if (IS_ERR(data))
		return PTR_ERR(data);

	bytes = efivar_entry_set_get_size(var, attributes, &datasize,
					  data, &set);
	if (!set && bytes) {
		if (bytes == -ENOENT)
			bytes = -EIO;
		goto out;
	}

	if (bytes == -ENOENT) {
		drop_nlink(inode);
		d_delete(file->f_path.dentry);
		dput(file->f_path.dentry);
	} else {
		mutex_lock(&inode->i_mutex);
		i_size_write(inode, datasize + sizeof(attributes));
		mutex_unlock(&inode->i_mutex);
	}

	bytes = count;

out:
	kfree(data);

	return bytes;
}

static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
		size_t count, loff_t *ppos)
{
	struct efivar_entry *var = file->private_data;
	unsigned long datasize = 0;
	u32 attributes;
	void *data;
	ssize_t size = 0;
	int err;

	err = efivar_entry_size(var, &datasize);

	/*
	 * efivarfs represents uncommitted variables with
	 * zero-length files. Reading them should return EOF.
	 */
	if (err == -ENOENT)
		return 0;
	else if (err)
		return err;

	data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);

	if (!data)
		return -ENOMEM;

	size = efivar_entry_get(var, &attributes, &datasize,
				data + sizeof(attributes));
	if (size)
		goto out_free;

	memcpy(data, &attributes, sizeof(attributes));
	size = simple_read_from_buffer(userbuf, count, ppos,
				       data, datasize + sizeof(attributes));
out_free:
	kfree(data);

	return size;
}

const struct file_operations efivarfs_file_operations = {
	.open	= simple_open,
	.read	= efivarfs_file_read,
	.write	= efivarfs_file_write,
	.llseek	= no_llseek,
};
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/efi.h>
	11	#include <linux/fs.h>
20b4fb48	12	#include <linux/slab.h>
d68772b7 MF	13
	14	#include "internal.h"
	15
d68772b7 MF	16	static ssize_t efivarfs_file_write(struct file *file,
	17	const char __user userbuf, size_t count, loff_t ppos)
	18	{
	19	struct efivar_entry *var = file->private_data;
	20	void *data;
	21	u32 attributes;
	22	struct inode *inode = file->f_mapping->host;
	23	unsigned long datasize = count - sizeof(attributes);
aca32b57	24	ssize_t bytes;
d68772b7 MF	25	bool set = false;
	26
	27	if (count < sizeof(attributes))
	28	return -EINVAL;
	29
	30	if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
	31	return -EFAULT;
	32
	33	if (attributes & ~(EFI_VARIABLE_MASK))
	34	return -EINVAL;
	35
aca32b57 GB	36	data = memdup_user(userbuf + sizeof(attributes), datasize);
	37	if (IS_ERR(data))
	38	return PTR_ERR(data);
d68772b7 MF	39
	40	bytes = efivar_entry_set_get_size(var, attributes, &datasize,
	41	data, &set);
3fab70c1 LX	42	if (!set && bytes) {
	43	if (bytes == -ENOENT)
	44	bytes = -EIO;
d68772b7	45	goto out;
3fab70c1	46	}
d68772b7 MF	47
	48	if (bytes == -ENOENT) {
	49	drop_nlink(inode);
b583043e AV	50	d_delete(file->f_path.dentry);
b583043e AV	51	dput(file->f_path.dentry);
d68772b7 MF	52	} else {
	53	mutex_lock(&inode->i_mutex);
	54	i_size_write(inode, datasize + sizeof(attributes));
	55	mutex_unlock(&inode->i_mutex);
	56	}
	57
	58	bytes = count;
	59
	60	out:
	61	kfree(data);
	62
	63	return bytes;
	64	}
	65
	66	static ssize_t efivarfs_file_read(struct file file, char __user userbuf,
	67	size_t count, loff_t *ppos)
	68	{
	69	struct efivar_entry *var = file->private_data;
	70	unsigned long datasize = 0;
	71	u32 attributes;
	72	void *data;
	73	ssize_t size = 0;
	74	int err;
	75
	76	err = efivar_entry_size(var, &datasize);
3fab70c1 LX	77
	78	/*
	79	* efivarfs represents uncommitted variables with
	80	* zero-length files. Reading them should return EOF.
	81	*/
	82	if (err == -ENOENT)
	83	return 0;
	84	else if (err)
d68772b7 MF	85	return err;
	86
	87	data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
	88
	89	if (!data)
	90	return -ENOMEM;
	91
	92	size = efivar_entry_get(var, &attributes, &datasize,
	93	data + sizeof(attributes));
	94	if (size)
	95	goto out_free;
	96
	97	memcpy(data, &attributes, sizeof(attributes));
	98	size = simple_read_from_buffer(userbuf, count, ppos,
	99	data, datasize + sizeof(attributes));
	100	out_free:
	101	kfree(data);
	102
	103	return size;
	104	}
	105
	106	const struct file_operations efivarfs_file_operations = {
f53f292e	107	.open = simple_open,
d68772b7 MF	108	.read = efivarfs_file_read,
	109	.write = efivarfs_file_write,
	110	.llseek = no_llseek,
	111	};