/* * 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, };