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diff --git a/rand/rand_core/src/os.rs b/rand/rand_core/src/os.rs
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+// Copyright 2019 Developers of the Rand project.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Interface to the random number generator of the operating system.
+// Note: keep this code in sync with the rand_os crate!
+
+use getrandom::getrandom;
+use crate::{CryptoRng, RngCore, Error, impls};
+
+/// A random number generator that retrieves randomness from from the
+/// operating system.
+///
+/// This is a zero-sized struct. It can be freely constructed with `OsRng`.
+///
+/// The implementation is provided by the [getrandom] crate. Refer to
+/// [getrandom] documentation for details.
+///
+/// This struct is only available when specifying the crate feature `getrandom`
+/// or `std`. When using the `rand` lib, it is also available as `rand::rngs::OsRng`.
+///
+/// # Blocking and error handling
+///
+/// It is possible that when used during early boot the first call to `OsRng`
+/// will block until the system's RNG is initialised. It is also possible
+/// (though highly unlikely) for `OsRng` to fail on some platforms, most
+/// likely due to system mis-configuration.
+///
+/// After the first successful call, it is highly unlikely that failures or
+/// significant delays will occur (although performance should be expected to
+/// be much slower than a user-space PRNG).
+///
+/// # Usage example
+/// ```
+/// use rand_core::{RngCore, OsRng};
+///
+/// let mut key = [0u8; 16];
+/// OsRng.fill_bytes(&mut key);
+/// let random_u64 = OsRng.next_u64();
+/// ```
+///
+/// [getrandom]: https://crates.io/crates/getrandom
+#[derive(Clone, Copy, Debug, Default)]
+pub struct OsRng;
+
+impl CryptoRng for OsRng {}
+
+impl RngCore for OsRng {
+    fn next_u32(&mut self) -> u32 {
+        impls::next_u32_via_fill(self)
+    }
+
+    fn next_u64(&mut self) -> u64 {
+        impls::next_u64_via_fill(self)
+    }
+
+    fn fill_bytes(&mut self, dest: &mut [u8]) {
+        if let Err(e) = self.try_fill_bytes(dest) {
+            panic!("Error: {}", e);
+        }
+    }
+
+    fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
+        getrandom(dest)?;
+        Ok(())
+    }
+}
+
+#[test]
+fn test_os_rng() {
+    let x = OsRng.next_u64();
+    let y = OsRng.next_u64();
+    assert!(x != 0);
+    assert!(x != y);
+}
+
+#[test]
+fn test_construction() {
+    let mut rng = OsRng::default();
+    assert!(rng.next_u64() != 0);
+}