Update nitrokey crate to 0.4.0

This change finally updates the version of the nitrokey crate that we
consume to 0.4.0. Along with that we update rand_core, one of its
dependencies, to 0.5.1. Further more we add cfg-if in version 0.1.10 and
getrandom in version 0.1.13, both of which are now new (non-development)
dependencies.

Import subrepo nitrokey/:nitrokey at e81057037e9b4f370b64c0a030a725bc6bdfb870
Import subrepo cfg-if/:cfg-if at 4484a6faf816ff8058088ad857b0c6bb2f4b02b2
Import subrepo getrandom/:getrandom at d661aa7e1b8cc80b47dabe3d2135b3b47d2858af
Import subrepo rand/:rand at d877ed528248b52d947e0484364a4e1ae59ca502

1 files changed, 44 insertions, 0 deletions

diff --git a/getrandom/src/linux_android.rs b/getrandom/src/linux_android.rs
new file mode 100644
index 0000000..a29feb5
--- /dev/null
+++ b/getrandom/src/linux_android.rs
@@ -0,0 +1,44 @@
+// Copyright 2018 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.
+
+//! Implementation for Linux / Android
+use crate::util::LazyBool;
+use crate::util_libc::{last_os_error, sys_fill_exact};
+use crate::{use_file, Error};
+
+pub fn getrandom_inner(dest: &mut [u8]) -> Result<(), Error> {
+    static HAS_GETRANDOM: LazyBool = LazyBool::new();
+    if HAS_GETRANDOM.unsync_init(is_getrandom_available) {
+        sys_fill_exact(dest, |buf| unsafe {
+            getrandom(buf.as_mut_ptr() as *mut libc::c_void, buf.len(), 0)
+        })
+    } else {
+        use_file::getrandom_inner(dest)
+    }
+}
+
+fn is_getrandom_available() -> bool {
+    let res = unsafe { getrandom(core::ptr::null_mut(), 0, libc::GRND_NONBLOCK) };
+    if res < 0 {
+        match last_os_error().raw_os_error() {
+            Some(libc::ENOSYS) => false, // No kernel support
+            Some(libc::EPERM) => false,  // Blocked by seccomp
+            _ => true,
+        }
+    } else {
+        true
+    }
+}
+
+unsafe fn getrandom(
+    buf: *mut libc::c_void,
+    buflen: libc::size_t,
+    flags: libc::c_uint,
+) -> libc::ssize_t {
+    libc::syscall(libc::SYS_getrandom, buf, buflen, flags) as libc::ssize_t
+}