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// Copyright 2018 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
extern crate arch;
use arch::fdt::{begin_node, end_node, finish_fdt, property_string, start_fdt, Error};
use bootparam::setup_data;
use bootparam::SETUP_DTB;
use std::fs::File;
use std::io::BufRead;
use std::io::BufReader;
use std::mem;
use sys_util::{GuestAddress, GuestMemory};
use X86_64_FDT_MAX_SIZE;
/// Creates a flattened device tree containing all of the parameters for the
/// kernel and loads it into the guest memory at the specified offset.
/// # Arguments
/// * `fdt_max_size` - The amount of space reserved for the device tree
/// * `guest_mem` - The guest memory object
/// * `fdt_load_offset` - The offset into physical memory for the device tree
/// * `android_fstab` - the File object for the android fstab
pub fn create_fdt(
fdt_max_size: usize,
guest_mem: &GuestMemory,
fdt_load_offset: u64,
android_fstab: &mut File,
) -> Result<usize, Box<Error>> {
// Reserve space for the setup_data
let fdt_data_size = fdt_max_size - mem::size_of::<setup_data>();
let mut fdt = vec![0; fdt_data_size];
start_fdt(&mut fdt, fdt_data_size)?;
// The whole thing is put into one giant node with some top level properties
begin_node(&mut fdt, "")?;
begin_node(&mut fdt, "firmware")?;
begin_node(&mut fdt, "android")?;
property_string(&mut fdt, "compatible", "android,firmware")?;
begin_node(&mut fdt, "fstab")?;
property_string(&mut fdt, "compatible", "android,fstab")?;
let file = BufReader::new(android_fstab);
for line in file.lines().filter_map(|l| l.ok()) {
let vec = line.split(" ").collect::<Vec<&str>>();
assert_eq!(vec.len(), 5);
let partition = &vec[1][1..];
begin_node(&mut fdt, partition)?;
property_string(&mut fdt, "compatible", &("android,".to_owned() + partition))?;
property_string(&mut fdt, "dev", vec[0])?;
property_string(&mut fdt, "type", vec[2])?;
property_string(&mut fdt, "mnt_flags", vec[3])?;
property_string(&mut fdt, "fsmgr_flags", vec[4])?;
end_node(&mut fdt)?;
end_node(&mut fdt)?;
end_node(&mut fdt)?;
end_node(&mut fdt)?;
end_node(&mut fdt)?;
// Allocate another buffer so we can format and then write fdt to guest
let mut fdt_final = vec![0; fdt_data_size];
finish_fdt(&mut fdt, &mut fdt_final, fdt_data_size)?;
let mut hdr: setup_data = Default::default(); = 0;
hdr.type_ = SETUP_DTB;
hdr.len = fdt_data_size as u32;
assert!(fdt_data_size as u64 <= X86_64_FDT_MAX_SIZE);
let fdt_address = GuestAddress(fdt_load_offset);
.checked_offset(fdt_address, fdt_data_size as u64)
.write_obj_at_addr(hdr, fdt_address)
.map_err(|_| Error::FdtGuestMemoryWriteError)?;
let fdt_data_address = GuestAddress(fdt_load_offset + mem::size_of::<setup_data>() as u64);
let written = guest_mem
.write_at_addr(fdt_final.as_slice(), fdt_data_address)
.map_err(|_| Error::FdtGuestMemoryWriteError)?;
if written < fdt_data_size {
return Err(Box::new(Error::FdtGuestMemoryWriteError));