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//! SGX-specific extensions to general I/O primitives
//!
//! SGX file descriptors behave differently from Unix file descriptors. See the
//! description of [`TryIntoRawFd`](trait.TryIntoRawFd.html) for more details.
#![unstable(feature = "sgx_platform", issue = "56975")]
use crate::net;
pub use crate::sys::abi::usercalls::raw::Fd as RawFd;
use crate::sys::{self, AsInner, FromInner, IntoInner, TryIntoInner};
/// A trait to extract the raw SGX file descriptor from an underlying
/// object.
#[unstable(feature = "sgx_platform", issue = "56975")]
pub trait AsRawFd {
/// Extracts the raw file descriptor.
///
/// This method does **not** pass ownership of the raw file descriptor
/// to the caller. The descriptor is only guaranteed to be valid while
/// the original object has not yet been destroyed.
#[unstable(feature = "sgx_platform", issue = "56975")]
fn as_raw_fd(&self) -> RawFd;
}
/// A trait to express the ability to construct an object from a raw file
/// descriptor.
#[unstable(feature = "sgx_platform", issue = "56975")]
pub trait FromRawFd {
/// Constructs a new instance of `Self` from the given raw file
/// descriptor.
///
/// This function **consumes ownership** of the specified file
/// descriptor. The returned object will take responsibility for closing
/// it when the object goes out of scope.
///
/// This function is also unsafe as the primitives currently returned
/// have the contract that they are the sole owner of the file
/// descriptor they are wrapping. Usage of this function could
/// accidentally allow violating this contract which can cause memory
/// unsafety in code that relies on it being true.
#[unstable(feature = "sgx_platform", issue = "56975")]
unsafe fn from_raw_fd(fd: RawFd) -> Self;
}
/// A trait to express the ability to consume an object and acquire ownership of
/// its raw file descriptor.
#[unstable(feature = "sgx_platform", issue = "56975")]
pub trait TryIntoRawFd: Sized {
/// Consumes this object, returning the raw underlying file descriptor, if
/// this object is not cloned.
///
/// This function **transfers ownership** of the underlying file descriptor
/// to the caller. Callers are then the unique owners of the file descriptor
/// and must close the descriptor once it's no longer needed.
///
/// Unlike other platforms, on SGX, the file descriptor is shared between
/// all clones of an object. To avoid race conditions, this function will
/// only return `Ok` when called on the final clone.
#[unstable(feature = "sgx_platform", issue = "56975")]
fn try_into_raw_fd(self) -> Result<RawFd, Self>;
}
impl AsRawFd for net::TcpStream {
fn as_raw_fd(&self) -> RawFd {
*self.as_inner().as_inner().as_inner().as_inner()
}
}
impl AsRawFd for net::TcpListener {
fn as_raw_fd(&self) -> RawFd {
*self.as_inner().as_inner().as_inner().as_inner()
}
}
impl FromRawFd for net::TcpStream {
unsafe fn from_raw_fd(fd: RawFd) -> net::TcpStream {
let fd = sys::fd::FileDesc::from_inner(fd);
let socket = sys::net::Socket::from_inner(fd);
net::TcpStream::from_inner(sys::net::TcpStream::from_inner((socket, None)))
}
}
impl FromRawFd for net::TcpListener {
unsafe fn from_raw_fd(fd: RawFd) -> net::TcpListener {
let fd = sys::fd::FileDesc::from_inner(fd);
let socket = sys::net::Socket::from_inner(fd);
net::TcpListener::from_inner(sys::net::TcpListener::from_inner(socket))
}
}
impl TryIntoRawFd for net::TcpStream {
fn try_into_raw_fd(self) -> Result<RawFd, Self> {
let (socket, peer_addr) = self.into_inner().into_inner();
match socket.try_into_inner() {
Ok(fd) => Ok(fd.into_inner()),
Err(socket) => {
let sys = sys::net::TcpStream::from_inner((socket, peer_addr));
Err(net::TcpStream::from_inner(sys))
}
}
}
}
impl TryIntoRawFd for net::TcpListener {
fn try_into_raw_fd(self) -> Result<RawFd, Self> {
match self.into_inner().into_inner().try_into_inner() {
Ok(fd) => Ok(fd.into_inner()),
Err(socket) => {
let sys = sys::net::TcpListener::from_inner(socket);
Err(net::TcpListener::from_inner(sys))
}
}
}
}