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

   1 //! SGX-specific extensions to general I/O primitives
   2 //!
   3 //! SGX file descriptors behave differently from Unix file descriptors. See the
   4 //! description of [`TryIntoRawFd`](trait.TryIntoRawFd.html) for more details.
   5 #![unstable(feature = "sgx_platform", issue = "56975")]
   6
   7 use crate::net;
   8 pub use crate::sys::abi::usercalls::raw::Fd as RawFd;
   9 use crate::sys::{self, AsInner, FromInner, IntoInner, TryIntoInner};
  10
  11 /// A trait to extract the raw SGX file descriptor from an underlying
  12 /// object.
  13 #[unstable(feature = "sgx_platform", issue = "56975")]
  14 pub trait AsRawFd {
  15     /// Extracts the raw file descriptor.
  16     ///
  17     /// This method does **not** pass ownership of the raw file descriptor
  18     /// to the caller. The descriptor is only guaranteed to be valid while
  19     /// the original object has not yet been destroyed.
  20     #[unstable(feature = "sgx_platform", issue = "56975")]
  21     fn as_raw_fd(&self) -> RawFd;
  22 }
  23
  24 /// A trait to express the ability to construct an object from a raw file
  25 /// descriptor.
  26 #[unstable(feature = "sgx_platform", issue = "56975")]
  27 pub trait FromRawFd {
  28     /// Constructs a new instance of `Self` from the given raw file
  29     /// descriptor.
  30     ///
  31     /// This function **consumes ownership** of the specified file
  32     /// descriptor. The returned object will take responsibility for closing
  33     /// it when the object goes out of scope.
  34     ///
  35     /// This function is also unsafe as the primitives currently returned
  36     /// have the contract that they are the sole owner of the file
  37     /// descriptor they are wrapping. Usage of this function could
  38     /// accidentally allow violating this contract which can cause memory
  39     /// unsafety in code that relies on it being true.
  40     #[unstable(feature = "sgx_platform", issue = "56975")]
  41     unsafe fn from_raw_fd(fd: RawFd) -> Self;
  42 }
  43
  44 /// A trait to express the ability to consume an object and acquire ownership of
  45 /// its raw file descriptor.
  46 #[unstable(feature = "sgx_platform", issue = "56975")]
  47 pub trait TryIntoRawFd: Sized {
  48     /// Consumes this object, returning the raw underlying file descriptor, if
  49     /// this object is not cloned.
  50     ///
  51     /// This function **transfers ownership** of the underlying file descriptor
  52     /// to the caller. Callers are then the unique owners of the file descriptor
  53     /// and must close the descriptor once it's no longer needed.
  54     ///
  55     /// Unlike other platforms, on SGX, the file descriptor is shared between
  56     /// all clones of an object. To avoid race conditions, this function will
  57     /// only return `Ok` when called on the final clone.
  58     #[unstable(feature = "sgx_platform", issue = "56975")]
  59     fn try_into_raw_fd(self) -> Result<RawFd, Self>;
  60 }
  61
  62 impl AsRawFd for net::TcpStream {
  63     fn as_raw_fd(&self) -> RawFd {
  64         *self.as_inner().as_inner().as_inner().as_inner()
  65     }
  66 }
  67
  68 impl AsRawFd for net::TcpListener {
  69     fn as_raw_fd(&self) -> RawFd {
  70         *self.as_inner().as_inner().as_inner().as_inner()
  71     }
  72 }
  73
  74 impl FromRawFd for net::TcpStream {
  75     unsafe fn from_raw_fd(fd: RawFd) -> net::TcpStream {
  76         let fd = sys::fd::FileDesc::from_inner(fd);
  77         let socket = sys::net::Socket::from_inner(fd);
  78         net::TcpStream::from_inner(sys::net::TcpStream::from_inner((socket, None)))
  79     }
  80 }
  81
  82 impl FromRawFd for net::TcpListener {
  83     unsafe fn from_raw_fd(fd: RawFd) -> net::TcpListener {
  84         let fd = sys::fd::FileDesc::from_inner(fd);
  85         let socket = sys::net::Socket::from_inner(fd);
  86         net::TcpListener::from_inner(sys::net::TcpListener::from_inner(socket))
  87     }
  88 }
  89
  90 impl TryIntoRawFd for net::TcpStream {
  91     fn try_into_raw_fd(self) -> Result<RawFd, Self> {
  92         let (socket, peer_addr) = self.into_inner().into_inner();
  93         match socket.try_into_inner() {
  94             Ok(fd) => Ok(fd.into_inner()),
  95             Err(socket) => {
  96                 let sys = sys::net::TcpStream::from_inner((socket, peer_addr));
  97                 Err(net::TcpStream::from_inner(sys))
  98             }
  99         }
 100     }
 101 }
 102
 103 impl TryIntoRawFd for net::TcpListener {
 104     fn try_into_raw_fd(self) -> Result<RawFd, Self> {
 105         match self.into_inner().into_inner().try_into_inner() {
 106             Ok(fd) => Ok(fd.into_inner()),
 107             Err(socket) => {
 108                 let sys = sys::net::TcpListener::from_inner(socket);
 109                 Err(net::TcpListener::from_inner(sys))
 110             }
 111         }
 112     }
 113 }