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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.
// Exported interface to basic qcow functionality to be used from C.
use libc::{EINVAL, EIO, ENOSYS};
use std::ffi::CStr;
use std::fs::OpenOptions;
use std::os::raw::{c_char, c_int};
use disk::{DiskFile, ImageType, QcowFile};
use sys_util::{flock, FlockOperation};
#[no_mangle]
pub unsafe extern "C" fn create_qcow_with_size(path: *const c_char, virtual_size: u64) -> c_int {
// NULL pointers are checked, but this will access any other invalid pointer passed from C
// code. It's the caller's responsibility to pass a valid pointer.
if path.is_null() {
return -EINVAL;
}
let c_str = CStr::from_ptr(path);
let file_path = match c_str.to_str() {
Ok(s) => s,
Err(_) => return -EINVAL,
};
let file = match OpenOptions::new()
.create(true)
.read(true)
.write(true)
.open(file_path)
{
Ok(f) => f,
Err(_) => return -1,
};
match QcowFile::new(file, virtual_size) {
Ok(_) => 0,
Err(_) => -1,
}
}
#[no_mangle]
pub unsafe extern "C" fn expand_disk_image(path: *const c_char, virtual_size: u64) -> c_int {
// NULL pointers are checked, but this will access any other invalid pointer passed from C
// code. It's the caller's responsibility to pass a valid pointer.
if path.is_null() {
return -EINVAL;
}
let c_str = CStr::from_ptr(path);
let file_path = match c_str.to_str() {
Ok(s) => s,
Err(_) => return -EINVAL,
};
let raw_image = match OpenOptions::new().read(true).write(true).open(file_path) {
Ok(f) => f,
Err(_) => return -EIO,
};
// Lock the disk image to prevent other processes from using it.
if let Err(_) = flock(&raw_image, FlockOperation::LockExclusive, true) {
return -EIO;
}
let image_type = match disk::detect_image_type(&raw_image) {
Ok(t) => t,
Err(_) => return -EINVAL,
};
let disk_image: Box<dyn DiskFile> = match image_type {
ImageType::Raw => Box::new(raw_image),
ImageType::Qcow2 => match QcowFile::from(raw_image) {
Ok(f) => Box::new(f),
Err(_) => return -EINVAL,
},
_ => return -EINVAL,
};
// For safety against accidentally shrinking the disk image due to a
// programming error elsewhere, verify that the new size is larger than
// the current size. This is safe against races due to the exclusive
// flock() taken above - this is only an advisory lock, but it is also
// acquired by other instances of this function as well as crosvm
// itself when running a VM, so this should be safe in all cases that
// can access a disk image in normal operation.
let current_size = match disk_image.get_len() {
Ok(len) => len,
Err(_) => return -EIO,
};
if current_size >= virtual_size {
return 0;
}
match disk_image.set_len(virtual_size) {
Ok(_) => 0,
Err(_) => -ENOSYS,
}
}
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