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// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//! Type-safe bindings for Zircon vmo objects.
use {AsHandleRef, Cookied, HandleBased, Handle, HandleRef, Status};
use {sys, ok};
use std::{mem, ptr};
/// An object representing a Zircon
/// [virtual memory object](https://fuchsia.googlesource.com/zircon/+/master/docs/objects/vm_object.md).
///
/// As essentially a subtype of `Handle`, it can be freely interconverted.
#[derive(Debug, Eq, PartialEq)]
pub struct Vmo(Handle);
impl_handle_based!(Vmo);
impl Cookied for Vmo {}
impl Vmo {
/// Create a virtual memory object.
///
/// Wraps the
/// `zx_vmo_create`
/// syscall. See the
/// [Shared Memory: Virtual Memory Objects (VMOs)](https://fuchsia.googlesource.com/zircon/+/master/docs/concepts.md#Shared-Memory_Virtual-Memory-Objects-VMOs)
/// for more information.
pub fn create(size: u64) -> Result<Vmo, Status> {
let mut handle = 0;
let opts = 0;
let status = unsafe { sys::zx_vmo_create(size, opts, &mut handle) };
ok(status)?;
unsafe {
Ok(Vmo::from(Handle::from_raw(handle)))
}
}
/// Read from a virtual memory object.
///
/// Wraps the `zx_vmo_read` syscall.
pub fn read(&self, data: &mut [u8], offset: u64) -> Result<usize, Status> {
unsafe {
let mut actual = 0;
let status = sys::zx_vmo_read(self.raw_handle(), data.as_mut_ptr(),
offset, data.len(), &mut actual);
ok(status).map(|()| actual)
}
}
/// Write to a virtual memory object.
///
/// Wraps the `zx_vmo_write` syscall.
pub fn write(&self, data: &[u8], offset: u64) -> Result<usize, Status> {
unsafe {
let mut actual = 0;
let status = sys::zx_vmo_write(self.raw_handle(), data.as_ptr(),
offset, data.len(), &mut actual);
ok(status).map(|()| actual)
}
}
/// Get the size of a virtual memory object.
///
/// Wraps the `zx_vmo_get_size` syscall.
pub fn get_size(&self) -> Result<u64, Status> {
let mut size = 0;
let status = unsafe { sys::zx_vmo_get_size(self.raw_handle(), &mut size) };
ok(status).map(|()| size)
}
/// Attempt to change the size of a virtual memory object.
///
/// Wraps the `zx_vmo_set_size` syscall.
pub fn set_size(&self, size: u64) -> Result<(), Status> {
let status = unsafe { sys::zx_vmo_set_size(self.raw_handle(), size) };
ok(status)
}
/// Perform an operation on a range of a virtual memory object.
///
/// Wraps the
/// [zx_vmo_op_range](https://fuchsia.googlesource.com/zircon/+/master/docs/syscalls/vmo_op_range.md)
/// syscall.
pub fn op_range(&self, op: VmoOp, offset: u64, size: u64) -> Result<(), Status> {
let status = unsafe {
sys::zx_vmo_op_range(self.raw_handle(), op.into_raw(), offset, size, ptr::null_mut(), 0)
};
ok(status)
}
/// Look up a list of physical addresses corresponding to the pages held by the VMO from
/// `offset` to `offset`+`size`, and store them in `buffer`.
///
/// Wraps the
/// [zx_vmo_op_range](https://fuchsia.googlesource.com/zircon/+/master/docs/syscalls/vmo_op_range.md)
/// syscall with ZX_VMO_OP_LOOKUP.
pub fn lookup(&self, offset: u64, size: u64, buffer: &mut [sys::zx_paddr_t])
-> Result<(), Status>
{
let status = unsafe {
sys::zx_vmo_op_range(self.raw_handle(), VmoOp::LOOKUP.into_raw(), offset, size,
buffer.as_mut_ptr() as *mut u8, buffer.len() * mem::size_of::<sys::zx_paddr_t>())
};
ok(status)
}
/// Create a new virtual memory object that clones a range of this one.
///
/// Wraps the
/// syscall.
pub fn clone(&self, offset: u64, size: u64) -> Result<Vmo, Status> {
let mut out = 0;
let opts = sys::ZX_VMO_CLONE_COPY_ON_WRITE;
let status = unsafe {
sys::zx_vmo_clone(self.raw_handle(), opts, offset, size, &mut out)
};
ok(status)?;
unsafe { Ok(Vmo::from(Handle::from_raw(out))) }
}
}
/// VM Object opcodes
#[repr(C)]
#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
pub struct VmoOp(u32);
impl VmoOp {
pub fn from_raw(raw: u32) -> VmoOp {
VmoOp(raw)
}
pub fn into_raw(self) -> u32 {
self.0
}
}
assoc_consts!(VmoOp, [
COMMIT = sys::ZX_VMO_OP_COMMIT;
DECOMMIT = sys::ZX_VMO_OP_DECOMMIT;
LOCK = sys::ZX_VMO_OP_LOCK;
UNLOCK = sys::ZX_VMO_OP_UNLOCK;
LOOKUP = sys::ZX_VMO_OP_LOOKUP;
CACHE_SYNC = sys::ZX_VMO_OP_CACHE_SYNC;
CACHE_INVALIDATE = sys::ZX_VMO_OP_CACHE_INVALIDATE;
CACHE_CLEAN = sys::ZX_VMO_OP_CACHE_CLEAN;
CACHE_CLEAN_INVALIDATE = sys::ZX_VMO_OP_CACHE_CLEAN_INVALIDATE;
]);
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn vmo_get_size() {
let size = 16 * 1024 * 1024;
let vmo = Vmo::create(size).unwrap();
assert_eq!(size, vmo.get_size().unwrap());
}
#[test]
fn vmo_set_size() {
let start_size = 12;
let vmo = Vmo::create(start_size).unwrap();
assert_eq!(start_size, vmo.get_size().unwrap());
// Change the size and make sure the new size is reported
let new_size = 23;
assert!(vmo.set_size(new_size).is_ok());
assert_eq!(new_size, vmo.get_size().unwrap());
}
#[test]
fn vmo_read_write() {
let mut vec1 = vec![0; 16];
let vmo = Vmo::create(vec1.len() as u64).unwrap();
assert_eq!(vmo.write(b"abcdef", 0), Ok(6));
assert_eq!(16, vmo.read(&mut vec1, 0).unwrap());
assert_eq!(b"abcdef", &vec1[0..6]);
assert_eq!(vmo.write(b"123", 2), Ok(3));
assert_eq!(16, vmo.read(&mut vec1, 0).unwrap());
assert_eq!(b"ab123f", &vec1[0..6]);
assert_eq!(15, vmo.read(&mut vec1, 1).unwrap());
assert_eq!(b"b123f", &vec1[0..5]);
}
#[test]
fn vmo_op_range_unsupported() {
let vmo = Vmo::create(12).unwrap();
assert_eq!(vmo.op_range(VmoOp::LOCK, 0, 1), Err(Status::NOT_SUPPORTED));
assert_eq!(vmo.op_range(VmoOp::UNLOCK, 0, 1), Err(Status::NOT_SUPPORTED));
}
#[test]
fn vmo_lookup() {
let vmo = Vmo::create(12).unwrap();
let mut buffer = vec![0; 2];
// Lookup will fail as it is not committed yet.
assert_eq!(vmo.lookup(0, 12, &mut buffer), Err(Status::NO_MEMORY));
// COMMIT and try again.
assert_eq!(vmo.op_range(VmoOp::COMMIT, 0, 12), Ok(()));
assert_eq!(vmo.lookup(0, 12, &mut buffer), Ok(()));
assert_ne!(buffer[0], 0);
assert_eq!(buffer[1], 0);
// If we decommit then lookup should go back to failing.
assert_eq!(vmo.op_range(VmoOp::DECOMMIT, 0, 12), Ok(()));
assert_eq!(vmo.lookup(0, 12, &mut buffer), Err(Status::NO_MEMORY));
}
#[test]
fn vmo_cache() {
let vmo = Vmo::create(12).unwrap();
// Cache operations should all succeed.
assert_eq!(vmo.op_range(VmoOp::CACHE_SYNC, 0, 12), Ok(()));
assert_eq!(vmo.op_range(VmoOp::CACHE_INVALIDATE, 0, 12), Ok(()));
assert_eq!(vmo.op_range(VmoOp::CACHE_CLEAN, 0, 12), Ok(()));
assert_eq!(vmo.op_range(VmoOp::CACHE_CLEAN_INVALIDATE, 0, 12), Ok(()));
}
#[test]
fn vmo_clone() {
let original = Vmo::create(12).unwrap();
assert_eq!(original.write(b"one", 0), Ok(3));
// Clone the VMO, and make sure it contains what we expect.
let clone = original.clone(0, 10).unwrap();
let mut read_buffer = vec![0; 16];
assert_eq!(clone.read(&mut read_buffer, 0), Ok(10));
assert_eq!(&read_buffer[0..3], b"one");
// Writing to the original will affect the clone too, surprisingly.
assert_eq!(original.write(b"two", 0), Ok(3));
assert_eq!(original.read(&mut read_buffer, 0), Ok(12));
assert_eq!(&read_buffer[0..3], b"two");
assert_eq!(clone.read(&mut read_buffer, 0), Ok(10));
assert_eq!(&read_buffer[0..3], b"two");
// However, writing to the clone will not affect the original
assert_eq!(clone.write(b"three", 0), Ok(5));
assert_eq!(original.read(&mut read_buffer, 0), Ok(12));
assert_eq!(&read_buffer[0..3], b"two");
assert_eq!(clone.read(&mut read_buffer, 0), Ok(10));
assert_eq!(&read_buffer[0..5], b"three");
// And now that the copy-on-write has happened, writing to the original will not affect the
// clone. How bizarre.
assert_eq!(original.write(b"four", 0), Ok(4));
assert_eq!(original.read(&mut read_buffer, 0), Ok(12));
assert_eq!(&read_buffer[0..4], b"four");
assert_eq!(clone.read(&mut read_buffer, 0), Ok(10));
assert_eq!(&read_buffer[0..5], b"three");
}
}