1 files changed, 124 insertions, 0 deletions
diff --git a/library/std/src/sys/unix/ext/io.rs b/library/std/src/sys/unix/ext/io.rs
new file mode 100644
index 00000000000..5077e2e28d1
--- /dev/null
+++ b/library/std/src/sys/unix/ext/io.rs
@@ -0,0 +1,124 @@
+//! Unix-specific extensions to general I/O primitives
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+use crate::fs;
+use crate::io;
+use crate::os::raw;
+use crate::sys;
+use crate::sys_common::{AsInner, FromInner, IntoInner};
+
+/// Raw file descriptors.
+#[stable(feature = "rust1", since = "1.0.0")]
+pub type RawFd = raw::c_int;
+
+/// A trait to extract the raw unix file descriptor from an underlying
+/// object.
+///
+/// This is only available on unix platforms and must be imported in order
+/// to call the method. Windows platforms have a corresponding `AsRawHandle`
+/// and `AsRawSocket` set of traits.
+#[stable(feature = "rust1", since = "1.0.0")]
+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.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn as_raw_fd(&self) -> RawFd;
+}
+
+/// A trait to express the ability to construct an object from a raw file
+/// descriptor.
+#[stable(feature = "from_raw_os", since = "1.1.0")]
+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.
+    #[stable(feature = "from_raw_os", since = "1.1.0")]
+    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.
+#[stable(feature = "into_raw_os", since = "1.4.0")]
+pub trait IntoRawFd {
+    /// Consumes this object, returning the raw underlying file descriptor.
+    ///
+    /// 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.
+    #[stable(feature = "into_raw_os", since = "1.4.0")]
+    fn into_raw_fd(self) -> RawFd;
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl AsRawFd for fs::File {
+    fn as_raw_fd(&self) -> RawFd {
+        self.as_inner().fd().raw()
+    }
+}
+#[stable(feature = "from_raw_os", since = "1.1.0")]
+impl FromRawFd for fs::File {
+    unsafe fn from_raw_fd(fd: RawFd) -> fs::File {
+        fs::File::from_inner(sys::fs::File::from_inner(fd))
+    }
+}
+#[stable(feature = "into_raw_os", since = "1.4.0")]
+impl IntoRawFd for fs::File {
+    fn into_raw_fd(self) -> RawFd {
+        self.into_inner().into_fd().into_raw()
+    }
+}
+
+#[stable(feature = "asraw_stdio", since = "1.21.0")]
+impl AsRawFd for io::Stdin {
+    fn as_raw_fd(&self) -> RawFd {
+        libc::STDIN_FILENO
+    }
+}
+
+#[stable(feature = "asraw_stdio", since = "1.21.0")]
+impl AsRawFd for io::Stdout {
+    fn as_raw_fd(&self) -> RawFd {
+        libc::STDOUT_FILENO
+    }
+}
+
+#[stable(feature = "asraw_stdio", since = "1.21.0")]
+impl AsRawFd for io::Stderr {
+    fn as_raw_fd(&self) -> RawFd {
+        libc::STDERR_FILENO
+    }
+}
+
+#[stable(feature = "asraw_stdio_locks", since = "1.35.0")]
+impl<'a> AsRawFd for io::StdinLock<'a> {
+    fn as_raw_fd(&self) -> RawFd {
+        libc::STDIN_FILENO
+    }
+}
+
+#[stable(feature = "asraw_stdio_locks", since = "1.35.0")]
+impl<'a> AsRawFd for io::StdoutLock<'a> {
+    fn as_raw_fd(&self) -> RawFd {
+        libc::STDOUT_FILENO
+    }
+}
+
+#[stable(feature = "asraw_stdio_locks", since = "1.35.0")]
+impl<'a> AsRawFd for io::StderrLock<'a> {
+    fn as_raw_fd(&self) -> RawFd {
+        libc::STDERR_FILENO
+    }
+}