Auto merge of #31738 - seanmonstar:sys-rand, r=alexcrichton

4 files changed, 347 insertions, 0 deletions

diff --git a/src/libstd/sys/unix/mod.rs b/src/libstd/sys/unix/mod.rs
index 9cae36fb726..c332d6035ee 100644
--- a/src/libstd/sys/unix/mod.rs
+++ b/src/libstd/sys/unix/mod.rs
@@ -42,6 +42,7 @@ pub mod os;
 pub mod os_str;
 pub mod pipe;
 pub mod process;
+pub mod rand;
 pub mod rwlock;
 pub mod stack_overflow;
 pub mod thread;
diff --git a/src/libstd/sys/unix/rand.rs b/src/libstd/sys/unix/rand.rs
new file mode 100644
index 00000000000..fa504ade084
--- /dev/null
+++ b/src/libstd/sys/unix/rand.rs
@@ -0,0 +1,273 @@
+// 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.
+
+pub use self::imp::OsRng;
+
+#[cfg(all(unix, not(target_os = "ios"), not(target_os = "openbsd")))]
+mod imp {
+    use self::OsRngInner::*;
+
+    use fs::File;
+    use io;
+    use libc;
+    use mem;
+    use rand::Rng;
+    use rand::reader::ReaderRng;
+    use sys::os::errno;
+
+    #[cfg(all(target_os = "linux",
+              any(target_arch = "x86_64",
+                  target_arch = "x86",
+                  target_arch = "arm",
+                  target_arch = "aarch64",
+                  target_arch = "powerpc",
+                  target_arch = "powerpc64")))]
+    fn getrandom(buf: &mut [u8]) -> 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(target_arch = "arm")]
+        const NR_GETRANDOM: libc::c_long = 384;
+        #[cfg(any(target_arch = "powerpc", target_arch = "powerpc64"))]
+        const NR_GETRANDOM: libc::c_long = 359;
+        #[cfg(target_arch = "aarch64")]
+        const NR_GETRANDOM: libc::c_long = 278;
+
+        unsafe {
+            libc::syscall(NR_GETRANDOM, buf.as_mut_ptr(), buf.len(), 0)
+        }
+    }
+
+    #[cfg(not(all(target_os = "linux",
+                  any(target_arch = "x86_64",
+                      target_arch = "x86",
+                      target_arch = "arm",
+                      target_arch = "aarch64",
+                      target_arch = "powerpc",
+                      target_arch = "powerpc64"))))]
+    fn getrandom(_buf: &mut [u8]) -> libc::c_long { -1 }
+
+    fn getrandom_fill_bytes(v: &mut [u8]) {
+        let mut read = 0;
+        while read < v.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 usize;
+            }
+        }
+    }
+
+    fn getrandom_next_u32() -> u32 {
+        let mut buf: [u8; 4] = [0; 4];
+        getrandom_fill_bytes(&mut buf);
+        unsafe { mem::transmute::<[u8; 4], u32>(buf) }
+    }
+
+    fn getrandom_next_u64() -> u64 {
+        let mut buf: [u8; 8] = [0; 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",
+                  target_arch = "powerpc64")))]
+    fn is_getrandom_available() -> bool {
+        use sync::atomic::{AtomicBool, Ordering};
+        use sync::Once;
+
+        static CHECKER: Once = Once::new();
+        static AVAILABLE: AtomicBool = AtomicBool::new(false);
+
+        CHECKER.call_once(|| {
+            let mut buf: [u8; 0] = [];
+            let result = getrandom(&mut buf);
+            let available = if result == -1 {
+                let err = io::Error::last_os_error().raw_os_error();
+                err != Some(libc::ENOSYS)
+            } else {
+                true
+            };
+            AVAILABLE.store(available, Ordering::Relaxed);
+        });
+
+        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",
+                      target_arch = "powerpc64"))))]
+    fn is_getrandom_available() -> bool { false }
+
+    pub struct OsRng {
+        inner: OsRngInner,
+    }
+
+    enum OsRngInner {
+        OsGetrandomRng,
+        OsReaderRng(ReaderRng<File>),
+    }
+
+    impl OsRng {
+        /// Create a new `OsRng`.
+        pub fn new() -> io::Result<OsRng> {
+            if is_getrandom_available() {
+                return Ok(OsRng { inner: OsGetrandomRng });
+            }
+
+            let reader = try!(File::open("/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 = "openbsd")]
+mod imp {
+    use io;
+    use libc;
+    use mem;
+    use sys::os::errno;
+    use rand::Rng;
+
+    pub struct OsRng {
+        // dummy field to ensure that this struct cannot be constructed outside
+        // of this module
+        _dummy: (),
+    }
+
+    impl OsRng {
+        /// Create a new `OsRng`.
+        pub fn new() -> io::Result<OsRng> {
+            Ok(OsRng { _dummy: () })
+        }
+    }
+
+    impl Rng for OsRng {
+        fn next_u32(&mut self) -> u32 {
+            let mut v = [0; 4];
+            self.fill_bytes(&mut v);
+            unsafe { mem::transmute(v) }
+        }
+        fn next_u64(&mut self) -> u64 {
+            let mut v = [0; 8];
+            self.fill_bytes(&mut v);
+            unsafe { mem::transmute(v) }
+        }
+        fn fill_bytes(&mut self, v: &mut [u8]) {
+            // getentropy(2) permits a maximum buffer size of 256 bytes
+            for s in v.chunks_mut(256) {
+                let ret = unsafe {
+                    libc::getentropy(s.as_mut_ptr() as *mut libc::c_void, s.len())
+                };
+                if ret == -1 {
+                    panic!("unexpected getentropy error: {}", errno());
+                }
+            }
+        }
+    }
+}
+
+#[cfg(target_os = "ios")]
+mod imp {
+    use io;
+    use mem;
+    use ptr;
+    use rand::Rng;
+    use libc::{c_int, size_t};
+
+    pub struct OsRng {
+        // dummy field to ensure that this struct cannot be constructed outside
+        // of this module
+        _dummy: (),
+    }
+
+    enum SecRandom {}
+
+    #[allow(non_upper_case_globals)]
+    const kSecRandomDefault: *const SecRandom = ptr::null();
+
+    #[link(name = "Security", kind = "framework")]
+    #[cfg(not(cargobuild))]
+    extern {}
+
+    extern {
+        fn SecRandomCopyBytes(rnd: *const SecRandom,
+                              count: size_t, bytes: *mut u8) -> c_int;
+    }
+
+    impl OsRng {
+        /// Create a new `OsRng`.
+        pub fn new() -> io::Result<OsRng> {
+            Ok(OsRng { _dummy: () })
+        }
+    }
+
+    impl Rng for OsRng {
+        fn next_u32(&mut self) -> u32 {
+            let mut v = [0; 4];
+            self.fill_bytes(&mut v);
+            unsafe { mem::transmute(v) }
+        }
+        fn next_u64(&mut self) -> u64 {
+            let mut v = [0; 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: {}",
+                       io::Error::last_os_error());
+            }
+        }
+    }
+}
diff --git a/src/libstd/sys/windows/mod.rs b/src/libstd/sys/windows/mod.rs
index 9ecef5ee92c..765e6e09427 100644
--- a/src/libstd/sys/windows/mod.rs
+++ b/src/libstd/sys/windows/mod.rs
@@ -33,6 +33,7 @@ pub mod os;
 pub mod os_str;
 pub mod pipe;
 pub mod process;
+pub mod rand;
 pub mod rwlock;
 pub mod stack_overflow;
 pub mod thread;
diff --git a/src/libstd/sys/windows/rand.rs b/src/libstd/sys/windows/rand.rs
new file mode 100644
index 00000000000..fdd260b6e28
--- /dev/null
+++ b/src/libstd/sys/windows/rand.rs
@@ -0,0 +1,72 @@
+// 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.
+
+
+use io;
+use mem;
+use rand::Rng;
+use sys::c;
+
+pub struct OsRng {
+    hcryptprov: c::HCRYPTPROV
+}
+
+impl OsRng {
+    /// Create a new `OsRng`.
+    pub fn new() -> io::Result<OsRng> {
+        let mut hcp = 0;
+        let ret = unsafe {
+            c::CryptAcquireContextA(&mut hcp, 0 as c::LPCSTR, 0 as c::LPCSTR,
+                                    c::PROV_RSA_FULL,
+                                    c::CRYPT_VERIFYCONTEXT | c::CRYPT_SILENT)
+        };
+
+        if ret == 0 {
+            Err(io::Error::last_os_error())
+        } else {
+            Ok(OsRng { hcryptprov: hcp })
+        }
+    }
+}
+
+impl Rng for OsRng {
+    fn next_u32(&mut self) -> u32 {
+        let mut v = [0; 4];
+        self.fill_bytes(&mut v);
+        unsafe { mem::transmute(v) }
+    }
+    fn next_u64(&mut self) -> u64 {
+        let mut v = [0; 8];
+        self.fill_bytes(&mut v);
+        unsafe { mem::transmute(v) }
+    }
+    fn fill_bytes(&mut self, v: &mut [u8]) {
+        let ret = unsafe {
+            c::CryptGenRandom(self.hcryptprov, v.len() as c::DWORD,
+                              v.as_mut_ptr())
+        };
+        if ret == 0 {
+            panic!("couldn't generate random bytes: {}",
+                   io::Error::last_os_error());
+        }
+    }
+}
+
+impl Drop for OsRng {
+    fn drop(&mut self) {
+        let ret = unsafe {
+            c::CryptReleaseContext(self.hcryptprov, 0)
+        };
+        if ret == 0 {
+            panic!("couldn't release context: {}",
+                   io::Error::last_os_error());
+        }
+    }
+}