Auto merge of #57119 - jethrogb:jb/sgx-os-mod2, r=joshtriplett

Add `io` and `arch` modules to `std::os::fortanix_sgx`

This PR adds two more (unstable) modules to `std::os::fortanix_sgx` for the `x86_64-fortanix-unknown-sgx` target.

### io
`io` allows conversion between raw file descriptors and Rust types, similar to `std::os::unix::io`.

### arch
`arch` exposes the `ENCLU[EREPORT]` and `ENCLU[EGETKEY]` instructions. The current functions are very likely not going to be the final form of these functions (see also fortanix/rust-sgx#15), but this should be sufficient to enable experimentation in libraries. I tried using the actual types (from the [`sgx-isa` crate](https://crates.io/crates/sgx-isa)) instead of byte arrays, but that would make `std` dependent on the `bitflags` crate which I didn't want to do at this time.

src/libstd/lib.rs

@@ -304,7 +304,8 @@
 #![feature(alloc_layout_extra)]
 #![feature(maybe_uninit)]
 #![cfg_attr(target_env = "sgx", feature(global_asm, range_contains, slice_index_methods,
-                                        decl_macro, coerce_unsized, sgx_platform))]
+                                        decl_macro, coerce_unsized, sgx_platform,
+                                        min_const_unsafe_fn))]
 
 #![default_lib_allocator]
 

src/libstd/os/fortanix_sgx/mod.rs

@@ -55,3 +55,5 @@ pub mod usercalls {
 pub mod mem {
     pub use sys::abi::mem::*;
 }
+
+pub use sys::ext::{io, arch};

src/libstd/sys/sgx/ext/arch.rs

@@ -0,0 +1,84 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! SGX-specific access to architectural features.
+//!
+//! The functionality in this module is further documented in the Intel
+//! Software Developer's Manual, Volume 3, Chapter 40.
+#![unstable(feature = "sgx_platform", issue = "56975")]
+
+use mem::MaybeUninit;
+
+/// Wrapper struct to force 16-byte alignment.
+#[repr(align(16))]
+#[unstable(feature = "sgx_platform", issue = "56975")]
+pub struct Align16<T>(pub T);
+
+/// Wrapper struct to force 128-byte alignment.
+#[repr(align(128))]
+#[unstable(feature = "sgx_platform", issue = "56975")]
+pub struct Align128<T>(pub T);
+
+/// Wrapper struct to force 512-byte alignment.
+#[repr(align(512))]
+#[unstable(feature = "sgx_platform", issue = "56975")]
+pub struct Align512<T>(pub T);
+
+const ENCLU_EREPORT: u32 = 0;
+const ENCLU_EGETKEY: u32 = 1;
+
+/// Call the `EGETKEY` instruction to obtain a 128-bit secret key.
+#[unstable(feature = "sgx_platform", issue = "56975")]
+pub fn egetkey(request: &Align512<[u8; 512]>) -> Result<Align16<[u8; 16]>, u32> {
+    unsafe {
+        let mut out = MaybeUninit::uninitialized();
+        let error;
+
+        asm!(
+            "enclu"
+            : "={eax}"(error)
+            : "{eax}"(ENCLU_EGETKEY),
+              "{rbx}"(request),
+              "{rcx}"(out.get_mut())
+            : "flags"
+        );
+
+        match error {
+            0 => Ok(out.into_inner()),
+            err => Err(err),
+        }
+    }
+}
+
+/// Call the `EREPORT` instruction.
+///
+/// This creates a cryptographic report describing the contents of the current
+/// enclave. The report may be verified by the enclave described in
+/// `targetinfo`.
+#[unstable(feature = "sgx_platform", issue = "56975")]
+pub fn ereport(
+    targetinfo: &Align512<[u8; 512]>,
+    reportdata: &Align128<[u8; 64]>,
+) -> Align512<[u8; 432]> {
+    unsafe {
+        let mut report = MaybeUninit::uninitialized();
+
+        asm!(
+            "enclu"
+            : /* no output registers */
+            : "{eax}"(ENCLU_EREPORT),
+              "{rbx}"(targetinfo),
+              "{rcx}"(reportdata),
+              "{rdx}"(report.get_mut())
+        );
+
+        report.into_inner()
+    }
+}

src/libstd/sys/sgx/ext/io.rs

@@ -0,0 +1,119 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! 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")]
+
+pub use sys::abi::usercalls::raw::Fd as RawFd;
+use net;
+use 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))
+            }
+        }
+    }
+}

src/libstd/sys/sgx/ext/mod.rs

@@ -0,0 +1,14 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![unstable(feature = "sgx_platform", issue = "56975")]
+
+pub mod arch;
+pub mod io;

src/libstd/sys/sgx/fd.rs

@@ -2,7 +2,7 @@ use fortanix_sgx_abi::Fd;
 
 use io;
 use mem;
-use sys_common::AsInner;
+use sys::{AsInner, FromInner, IntoInner};
 use super::abi::usercalls;
 
 #[derive(Debug)]
@@ -41,6 +41,20 @@ impl AsInner<Fd> for FileDesc {
     fn as_inner(&self) -> &Fd { &self.fd }
 }
 
+impl IntoInner<Fd> for FileDesc {
+    fn into_inner(self) -> Fd {
+        let fd = self.fd;
+        mem::forget(self);
+        fd
+    }
+}
+
+impl FromInner<Fd> for FileDesc {
+    fn from_inner(fd: Fd) -> FileDesc {
+        FileDesc { fd }
+    }
+}
+
 impl Drop for FileDesc {
     fn drop(&mut self) {
         usercalls::close(self.fd)

src/libstd/sys/sgx/mod.rs

@@ -17,6 +17,7 @@ pub mod backtrace;
 pub mod cmath;
 pub mod condvar;
 pub mod env;
+pub mod ext;
 pub mod fd;
 pub mod fs;
 pub mod memchr;
@@ -141,3 +142,9 @@ pub fn hashmap_random_keys() -> (u64, u64) {
     }
     (rdrand64(), rdrand64())
 }
+
+pub use sys_common::{AsInner, FromInner, IntoInner};
+
+pub trait TryIntoInner<Inner>: Sized {
+    fn try_into_inner(self) -> Result<Inner, Self>;
+}