| /* |
| * 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_dentry); |
| dput(file->f_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, |
| }; |