rust/src/libstd/rand/os.rs
2015-01-21 08:11:07 -08:00

412 lines
12 KiB
Rust

// Copyright 2013-2015 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.
//! Interfaces to the operating system provided random number
//! generators.
pub use self::imp::OsRng;
#[cfg(all(unix, not(target_os = "ios")))]
mod imp {
extern crate libc;
use self::OsRngInner::*;
use io::{IoResult, File};
use path::Path;
use rand::Rng;
use rand::reader::ReaderRng;
use result::Result::Ok;
use slice::SliceExt;
use mem;
use os::errno;
#[cfg(all(target_os = "linux",
any(target_arch = "x86_64",
target_arch = "x86",
target_arch = "arm",
target_arch = "aarch64",
target_arch = "powerpc")))]
fn getrandom(buf: &mut [u8]) -> libc::c_long {
extern "C" {
fn syscall(number: libc::c_long, ...) -> libc::c_long;
}
#[cfg(target_arch = "x86_64")]
const NR_GETRANDOM: libc::c_long = 318;
#[cfg(target_arch = "x86")]
const NR_GETRANDOM: libc::c_long = 355;
#[cfg(any(target_arch = "arm", target_arch = "aarch64"))]
const NR_GETRANDOM: libc::c_long = 384;
#[cfg(target_arch = "powerpc")]
const NR_GETRANDOM: libc::c_long = 384;
unsafe {
syscall(NR_GETRANDOM, buf.as_mut_ptr(), buf.len(), 0u)
}
}
#[cfg(not(all(target_os = "linux",
any(target_arch = "x86_64",
target_arch = "x86",
target_arch = "arm",
target_arch = "aarch64",
target_arch = "powerpc"))))]
fn getrandom(_buf: &mut [u8]) -> libc::c_long { -1 }
fn getrandom_fill_bytes(v: &mut [u8]) {
let mut read = 0;
let len = v.len();
while read < len {
let result = getrandom(&mut v[read..]);
if result == -1 {
let err = errno() as libc::c_int;
if err == libc::EINTR {
continue;
} else {
panic!("unexpected getrandom error: {}", err);
}
} else {
read += result as uint;
}
}
}
fn getrandom_next_u32() -> u32 {
let mut buf: [u8; 4] = [0u8; 4];
getrandom_fill_bytes(&mut buf);
unsafe { mem::transmute::<[u8; 4], u32>(buf) }
}
fn getrandom_next_u64() -> u64 {
let mut buf: [u8; 8] = [0u8; 8];
getrandom_fill_bytes(&mut buf);
unsafe { mem::transmute::<[u8; 8], u64>(buf) }
}
#[cfg(all(target_os = "linux",
any(target_arch = "x86_64",
target_arch = "x86",
target_arch = "arm",
target_arch = "aarch64",
target_arch = "powerpc")))]
fn is_getrandom_available() -> bool {
use sync::atomic::{AtomicBool, ATOMIC_BOOL_INIT, Ordering};
static GETRANDOM_CHECKED: AtomicBool = ATOMIC_BOOL_INIT;
static GETRANDOM_AVAILABLE: AtomicBool = ATOMIC_BOOL_INIT;
if !GETRANDOM_CHECKED.load(Ordering::Relaxed) {
let mut buf: [u8; 0] = [];
let result = getrandom(&mut buf);
let available = if result == -1 {
let err = errno() as libc::c_int;
err != libc::ENOSYS
} else {
true
};
GETRANDOM_AVAILABLE.store(available, Ordering::Relaxed);
GETRANDOM_CHECKED.store(true, Ordering::Relaxed);
available
} else {
GETRANDOM_AVAILABLE.load(Ordering::Relaxed)
}
}
#[cfg(not(all(target_os = "linux",
any(target_arch = "x86_64",
target_arch = "x86",
target_arch = "arm",
target_arch = "aarch64",
target_arch = "powerpc"))))]
fn is_getrandom_available() -> bool { false }
/// A random number generator that retrieves randomness straight from
/// the operating system. Platform sources:
///
/// - Unix-like systems (Linux, Android, Mac OSX): read directly from
/// `/dev/urandom`, or from `getrandom(2)` system call if available.
/// - Windows: calls `CryptGenRandom`, using the default cryptographic
/// service provider with the `PROV_RSA_FULL` type.
/// - iOS: calls SecRandomCopyBytes as /dev/(u)random is sandboxed.
///
/// This does not block.
pub struct OsRng {
inner: OsRngInner,
}
enum OsRngInner {
OsGetrandomRng,
OsReaderRng(ReaderRng<File>),
}
impl OsRng {
/// Create a new `OsRng`.
pub fn new() -> IoResult<OsRng> {
if is_getrandom_available() {
return Ok(OsRng { inner: OsGetrandomRng });
}
let reader = try!(File::open(&Path::new("/dev/urandom")));
let reader_rng = ReaderRng::new(reader);
Ok(OsRng { inner: OsReaderRng(reader_rng) })
}
}
impl Rng for OsRng {
fn next_u32(&mut self) -> u32 {
match self.inner {
OsGetrandomRng => getrandom_next_u32(),
OsReaderRng(ref mut rng) => rng.next_u32(),
}
}
fn next_u64(&mut self) -> u64 {
match self.inner {
OsGetrandomRng => getrandom_next_u64(),
OsReaderRng(ref mut rng) => rng.next_u64(),
}
}
fn fill_bytes(&mut self, v: &mut [u8]) {
match self.inner {
OsGetrandomRng => getrandom_fill_bytes(v),
OsReaderRng(ref mut rng) => rng.fill_bytes(v)
}
}
}
}
#[cfg(target_os = "ios")]
mod imp {
extern crate libc;
use io::{IoResult};
use marker::Sync;
use mem;
use os;
use rand::Rng;
use result::Result::{Ok};
use self::libc::{c_int, size_t};
use slice::SliceExt;
/// A random number generator that retrieves randomness straight from
/// the operating system. Platform sources:
///
/// - Unix-like systems (Linux, Android, Mac OSX): read directly from
/// `/dev/urandom`, or from `getrandom(2)` system call if available.
/// - Windows: calls `CryptGenRandom`, using the default cryptographic
/// service provider with the `PROV_RSA_FULL` type.
/// - iOS: calls SecRandomCopyBytes as /dev/(u)random is sandboxed.
///
/// This does not block.
#[allow(missing_copy_implementations)]
pub struct OsRng {
// dummy field to ensure that this struct cannot be constructed outside of this module
_dummy: (),
}
#[repr(C)]
struct SecRandom;
unsafe impl Sync for *const SecRandom {}
#[allow(non_upper_case_globals)]
static kSecRandomDefault: *const SecRandom = 0 as *const SecRandom;
#[link(name = "Security", kind = "framework")]
extern "C" {
fn SecRandomCopyBytes(rnd: *const SecRandom,
count: size_t, bytes: *mut u8) -> c_int;
}
impl OsRng {
/// Create a new `OsRng`.
pub fn new() -> IoResult<OsRng> {
Ok(OsRng { _dummy: () })
}
}
impl Rng for OsRng {
fn next_u32(&mut self) -> u32 {
let mut v = [0u8; 4];
self.fill_bytes(&mut v);
unsafe { mem::transmute(v) }
}
fn next_u64(&mut self) -> u64 {
let mut v = [0u8; 8];
self.fill_bytes(&mut v);
unsafe { mem::transmute(v) }
}
fn fill_bytes(&mut self, v: &mut [u8]) {
let ret = unsafe {
SecRandomCopyBytes(kSecRandomDefault, v.len() as size_t, v.as_mut_ptr())
};
if ret == -1 {
panic!("couldn't generate random bytes: {}", os::last_os_error());
}
}
}
}
#[cfg(windows)]
mod imp {
extern crate libc;
use io::{IoResult, IoError};
use mem;
use ops::Drop;
use os;
use rand::Rng;
use result::Result::{Ok, Err};
use self::libc::{DWORD, BYTE, LPCSTR, BOOL};
use self::libc::types::os::arch::extra::{LONG_PTR};
use slice::SliceExt;
type HCRYPTPROV = LONG_PTR;
/// A random number generator that retrieves randomness straight from
/// the operating system. Platform sources:
///
/// - Unix-like systems (Linux, Android, Mac OSX): read directly from
/// `/dev/urandom`, or from `getrandom(2)` system call if available.
/// - Windows: calls `CryptGenRandom`, using the default cryptographic
/// service provider with the `PROV_RSA_FULL` type.
/// - iOS: calls SecRandomCopyBytes as /dev/(u)random is sandboxed.
///
/// This does not block.
pub struct OsRng {
hcryptprov: HCRYPTPROV
}
static PROV_RSA_FULL: DWORD = 1;
static CRYPT_SILENT: DWORD = 64;
static CRYPT_VERIFYCONTEXT: DWORD = 0xF0000000;
#[allow(non_snake_case)]
extern "system" {
fn CryptAcquireContextA(phProv: *mut HCRYPTPROV,
pszContainer: LPCSTR,
pszProvider: LPCSTR,
dwProvType: DWORD,
dwFlags: DWORD) -> BOOL;
fn CryptGenRandom(hProv: HCRYPTPROV,
dwLen: DWORD,
pbBuffer: *mut BYTE) -> BOOL;
fn CryptReleaseContext(hProv: HCRYPTPROV, dwFlags: DWORD) -> BOOL;
}
impl OsRng {
/// Create a new `OsRng`.
pub fn new() -> IoResult<OsRng> {
let mut hcp = 0;
let ret = unsafe {
CryptAcquireContextA(&mut hcp, 0 as LPCSTR, 0 as LPCSTR,
PROV_RSA_FULL,
CRYPT_VERIFYCONTEXT | CRYPT_SILENT)
};
if ret == 0 {
Err(IoError::last_error())
} else {
Ok(OsRng { hcryptprov: hcp })
}
}
}
impl Rng for OsRng {
fn next_u32(&mut self) -> u32 {
let mut v = [0u8; 4];
self.fill_bytes(&mut v);
unsafe { mem::transmute(v) }
}
fn next_u64(&mut self) -> u64 {
let mut v = [0u8; 8];
self.fill_bytes(&mut v);
unsafe { mem::transmute(v) }
}
fn fill_bytes(&mut self, v: &mut [u8]) {
let ret = unsafe {
CryptGenRandom(self.hcryptprov, v.len() as DWORD,
v.as_mut_ptr())
};
if ret == 0 {
panic!("couldn't generate random bytes: {}", os::last_os_error());
}
}
}
impl Drop for OsRng {
fn drop(&mut self) {
let ret = unsafe {
CryptReleaseContext(self.hcryptprov, 0)
};
if ret == 0 {
panic!("couldn't release context: {}", os::last_os_error());
}
}
}
}
#[cfg(test)]
mod test {
use prelude::v1::*;
use sync::mpsc::channel;
use rand::Rng;
use super::OsRng;
use thread::Thread;
#[test]
fn test_os_rng() {
let mut r = OsRng::new().unwrap();
r.next_u32();
r.next_u64();
let mut v = [0u8; 1000];
r.fill_bytes(&mut v);
}
#[test]
fn test_os_rng_tasks() {
let mut txs = vec!();
for _ in range(0u, 20) {
let (tx, rx) = channel();
txs.push(tx);
Thread::spawn(move|| {
// wait until all the tasks are ready to go.
rx.recv().unwrap();
// deschedule to attempt to interleave things as much
// as possible (XXX: is this a good test?)
let mut r = OsRng::new().unwrap();
Thread::yield_now();
let mut v = [0u8; 1000];
for _ in range(0u, 100) {
r.next_u32();
Thread::yield_now();
r.next_u64();
Thread::yield_now();
r.fill_bytes(&mut v);
Thread::yield_now();
}
});
}
// start all the tasks
for tx in txs.iter() {
tx.send(()).unwrap();
}
}
}