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// vim: tw=80
// Copyright (C) 2020 Axcient
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
// PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
// USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
// SUCH DAMAGE.
use lazy_static::lazy_static;
use std::{
ffi::CStr,
sync::Mutex
};
use nbdkit::*;
// The RAM disk.
lazy_static! {
static ref SIZE : Mutex<usize> = Mutex::new(100 * 1024 * 1024);
static ref DISK : Mutex<Vec<u8>> = Mutex::new(vec![0;0]);
}
#[derive(Default)]
struct RamDisk {
// Box::new doesn't allocate anything unless we put some dummy
// fields here. In a real implementation you would put per-handle
// data here as required.
_not_used: i32,
}
impl Server for RamDisk {
fn name() -> &'static CStr {
c"ramdisk"
}
fn config(key: &str, val: &str) -> Result<()> {
match key {
"size" => {
*SIZE.lock().unwrap() = parse_size(val).unwrap() as usize;
Ok(())
},
_ => Err(Error::new(libc::EINVAL, "Unknown parameter"))
}
}
fn get_ready() -> Result<()> {
*DISK.lock().unwrap() = vec![0; *SIZE.lock().unwrap()];
Ok(())
}
fn open(_readonly: bool) -> Result<Box<dyn Server>> {
// The following lines will print the message below when
// nbdkit is run with the -v flag:
//
// nbdkit: ramdisk[1]: debug: connection opened: ...
let tls = is_tls().unwrap();
debug!("connection opened: readonly={}, tls={}", _readonly, tls);
Ok(Box::<RamDisk>::default())
}
fn get_size(&self) -> Result<i64> {
Ok(DISK.lock().unwrap().len() as i64)
}
fn read_at(&self, buf: &mut [u8], offset: u64) -> Result<()> {
let disk = DISK.lock().unwrap();
let ofs = offset as usize;
let end = ofs + buf.len();
buf.copy_from_slice(&disk[ofs..end]);
Ok(())
}
fn thread_model() -> Result<ThreadModel> where Self: Sized {
Ok(ThreadModel::Parallel)
}
fn write_at(&self, buf: &[u8], offset: u64, _flags: Flags) -> Result<()> {
let mut disk = DISK.lock().unwrap();
let ofs = offset as usize;
let end = ofs + buf.len();
disk[ofs..end].copy_from_slice(buf);
Ok(())
}
}
plugin!(RamDisk {thread_model, write_at, config, get_ready});
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