8 Update Solaris getrandom

src/lib.rs

@@ -100,6 +100,7 @@
     target_os = "android",
     target_os = "netbsd",
     target_os = "solaris",
+    target_os = "illumos",
     target_os = "redox",
     target_os = "dragonfly",
     target_os = "haiku",
@@ -138,7 +139,7 @@ mod_use!(cfg(target_os = "macos"), macos);
 mod_use!(cfg(target_os = "netbsd"), netbsd);
 mod_use!(cfg(target_os = "openbsd"), openbsd_bitrig);
 mod_use!(cfg(target_os = "redox"), redox);
-mod_use!(cfg(target_os = "solaris"), solaris);
+mod_use!(cfg(any(target_os = "solaris", target_os = "illumos")), solarish);
 mod_use!(cfg(windows), windows);
 mod_use!(cfg(target_env = "sgx"), sgx);
 
@@ -171,6 +172,7 @@ mod_use!(
         target_os = "freebsd",
         target_os = "fuchsia",
         target_os = "haiku",
+        target_os = "illumos",
         target_os = "ios",
         target_os = "linux",
         target_os = "macos",

src/solaris.rs

@@ -1,99 +0,0 @@
-// 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 the Solaris family
-//!
-//! Read from `/dev/random`, with chunks of limited size (1040 bytes).
-//! `/dev/random` uses the Hash_DRBG with SHA512 algorithm from NIST SP 800-90A.
-//! `/dev/urandom` uses the FIPS 186-2 algorithm, which is considered less
-//! secure. We choose to read from `/dev/random`.
-//!
-//! Since Solaris 11.3 the `getrandom` syscall is available. To make sure we can
-//! compile on both Solaris and on OpenSolaris derivatives, that do not have the
-//! function, we do a direct syscall instead of calling a library function.
-//!
-//! We have no way to differentiate between Solaris, illumos, SmartOS, etc.
-extern crate libc;
-
-use super::Error;
-use std::fs::File;
-use std::io;
-use std::io::Read;
-use std::cell::RefCell;
-use std::ops::DerefMut;
-
-enum RngSource {
-    GetRandom,
-    Device(File),
-}
-
-thread_local!(
-    static RNG_SOURCE: RefCell<Option<RngSource>> = RefCell::new(None);
-);
-
-fn syscall_getrandom(dest: &mut [u8]) -> Result<(), Error> {
-    // repalce with libc?
-    const SYS_GETRANDOM: libc::c_long = 143;
-
-    extern "C" {
-        fn syscall(number: libc::c_long, ...) -> libc::c_long;
-    }
-
-    let ret = unsafe {
-        syscall(SYS_GETRANDOM, dest.as_mut_ptr(), dest.len(), 0)
-    };
-    if ret == -1 || ret != dest.len() as i64 {
-        return Err(io::Error::last_os_error().into());
-    }
-    Ok(())
-}
-
-pub fn getrandom_inner(dest: &mut [u8]) -> Result<(), Error> {
-    // The documentation says 1024 is the maximum for getrandom
-    // and 1040 for /dev/random.
-    RNG_SOURCE.with(|f| {
-        use_init(f,
-        || {
-            let s = if is_getrandom_available() {
-                RngSource::GetRandom
-            } else {
-                RngSource::Device(File::open("/dev/random")?)
-            };
-            Ok(s)
-        }, |f| {
-            match f {
-                RngSource::GetRandom => for chunk in dest.chunks_mut(1024) {
-                    syscall_getrandom(chunk)
-                },
-                RngSource::Device(f) => for chunk in dest.chunks_mut(1040) {
-                    f.read_exact(dest).map_err(From::from)
-                },
-            }
-        })
-    })
-}
-
-fn is_getrandom_available() -> bool {
-    use std::sync::atomic::{AtomicBool, ATOMIC_BOOL_INIT, Ordering};
-    use std::sync::{Once, ONCE_INIT};
-
-    static CHECKER: Once = ONCE_INIT;
-    static AVAILABLE: AtomicBool = ATOMIC_BOOL_INIT;
-
-    CHECKER.call_once(|| {
-        let mut buf: [u8; 0] = [];
-        let available = match syscall_getrandom(&mut buf) {
-            Ok(()) => true,
-            Err(ref err) if err.raw_os_error() == Some(libc::ENOSYS) => false,
-            Err(_) => true,
-        };
-        AVAILABLE.store(available, Ordering::Relaxed);
-    });
-
-    AVAILABLE.load(Ordering::Relaxed)
-}

src/solarish.rs

@@ -0,0 +1,99 @@
+// 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 the Solaris family
+//!
+//! Read from `/dev/random`, with chunks of limited size (256 bytes).
+//! `/dev/random` uses the Hash_DRBG with SHA512 algorithm from NIST SP 800-90A.
+//! `/dev/urandom` uses the FIPS 186-2 algorithm, which is considered less
+//! secure. We choose to read from `/dev/random`.
+//!
+//! Since Solaris 11.3 and mid-2015 illumos, the `getrandom` syscall is available.
+//! To make sure we can compile on both Solaris and its derivatives, as well as
+//! function, we check for the existance of getrandom(2) in libc by calling
+//! libc::dlsym.
+extern crate libc;
+
+use super::Error;
+use std::cell::RefCell;
+use std::fs::File;
+use std::io;
+use std::io::Read;
+use utils::use_init;
+
+#[cfg(target_os = "illumos")]
+type GetRandomFn = unsafe extern "C" fn(*mut u8, libc::size_t, libc::c_uint) -> libc::ssize_t;
+#[cfg(target_os = "solaris")]
+type GetRandomFn = unsafe extern "C" fn(*mut u8, libc::size_t, libc::c_uint) -> libc::c_int;
+
+enum RngSource {
+    GetRandom(GetRandomFn),
+    Device(File),
+}
+
+thread_local!(
+    static RNG_SOURCE: RefCell<Option<RngSource>> = RefCell::new(None);
+);
+
+fn libc_getrandom(rand: GetRandomFn, dest: &mut [u8]) -> Result<(), Error> {
+    let ret = unsafe { rand(dest.as_mut_ptr(), dest.len(), 0) as libc::ssize_t };
+
+    if ret == -1 || ret != dest.len() as libc::ssize_t {
+        Err(io::Error::last_os_error().into())
+    } else {
+        Ok(())
+    }
+}
+
+pub fn getrandom_inner(dest: &mut [u8]) -> Result<(), Error> {
+    // 256 bytes is the lowest common denominator across all the Solaris
+    // derived platforms for atomically obtaining random data.
+    RNG_SOURCE.with(|f| {
+        use_init(
+            f,
+            || {
+                let s = match fetch_getrandom() {
+                    Some(fptr) => RngSource::GetRandom(fptr),
+                    None => RngSource::Device(File::open("/dev/random")?),
+                };
+                Ok(s)
+            },
+            |f| {
+                match f {
+                    RngSource::GetRandom(rp) => {
+                        for chunk in dest.chunks_mut(256) {
+                            libc_getrandom(*rp, chunk)?
+                        }
+                    }
+                    RngSource::Device(randf) => {
+                        for chunk in dest.chunks_mut(256) {
+                            randf.read_exact(chunk)?
+                        }
+                    }
+                };
+                Ok(())
+            },
+        )
+    })
+}
+
+fn fetch_getrandom() -> Option<GetRandomFn> {
+    use std::mem;
+    use std::sync::atomic::{AtomicUsize, Ordering};
+
+    static FPTR: AtomicUsize = AtomicUsize::new(1);
+
+    if FPTR.load(Ordering::SeqCst) == 1 {
+        let name = "getrandom\0";
+        let addr = unsafe { libc::dlsym(libc::RTLD_DEFAULT, name.as_ptr() as *const _) as usize };
+        FPTR.store(addr, Ordering::SeqCst);
+    }
+
+    let ptr = FPTR.load(Ordering::SeqCst);
+    unsafe { mem::transmute::<usize, Option<GetRandomFn>>(ptr) }
+}