// Copyright © 2021 Intel Corporation

//

// SPDX-License-Identifier: Apache-2.0

#![no_main]

use std::ffi;

use std::fs::File;

use std::io::{self, Read, Seek, SeekFrom, Write};

use std::os::unix::io::{FromRawFd, RawFd};

use block::vhdx::Vhdx;

use libfuzzer_sys::{fuzz_target, Corpus};

// Populate the corpus directory with a test file:

// truncate -s 16M /tmp/source

// qemu-img convert -O vhdx /tmp/source fuzz/corpus/vhdx/test.vhdx

// Run with:

// cargo fuzz run vhdx -j 32 -- -max_len=16777216

fuzz_target!(|bytes: &[u8]| -> Corpus {

    let shm = memfd_create(&ffi::CString::new("fuzz").unwrap(), 0).unwrap();

    let mut disk_file: File = unsafe { File::from_raw_fd(shm) };

    disk_file.write_all(&bytes[..]).unwrap();

    disk_file.seek(SeekFrom::Start(0)).unwrap();

    let mut vhdx = match Vhdx::new(disk_file) {

        Ok(vhdx) => vhdx,

        Err(_) => return Corpus::Reject,

    };

    if matches!(vhdx.seek(SeekFrom::Start(0)).is_err(), true) {

        return Corpus::Reject;

    };

    let mut offset = 0;

    while offset < bytes.len() {

        let mut data = vec![0; 8192];

        vhdx.read_exact(&mut data).ok();

        offset += data.len();

    }

    if matches!(vhdx.seek(SeekFrom::Start(0)).is_err(), true) {

        return Corpus::Reject;

    };

    offset = 0;

    while offset < bytes.len() {

        let data = vec![0; 8192];

        vhdx.write_all(&data).ok();

        offset += data.len();

    }

    Corpus::Keep

});

fn memfd_create(name: &ffi::CStr, flags: u32) -> Result<RawFd, io::Error> {

    let res = unsafe { libc::syscall(libc::SYS_memfd_create, name.as_ptr(), flags) };

    if res < 0 {

        Err(io::Error::last_os_error())

    } else {

        Ok(res as RawFd)

    }

}