vendor/getrandom-0.1.14/src/solaris_illumos.rs

   1 // Copyright 2018 Developers of the Rand project.
   2 //
   3 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   4 // https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   5 // <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
   6 // option. This file may not be copied, modified, or distributed
   7 // except according to those terms.
   8
   9 //! Implementation for the Solaris family
  10 //!
  11 //! Read from `/dev/random`, with chunks of limited size (256 bytes).
  12 //! `/dev/random` uses the Hash_DRBG with SHA512 algorithm from NIST SP 800-90A.
  13 //! `/dev/urandom` uses the FIPS 186-2 algorithm, which is considered less
  14 //! secure. We choose to read from `/dev/random`.
  15 //!
  16 //! Since Solaris 11.3 and mid-2015 illumos, the `getrandom` syscall is available.
  17 //! To make sure we can compile on both Solaris and its derivatives, as well as
  18 //! function, we check for the existence of getrandom(2) in libc by calling
  19 //! libc::dlsym.
  20 use crate::util_libc::{sys_fill_exact, Weak};
  21 use crate::{use_file, Error};
  22 use core::mem;
  23
  24 #[cfg(target_os = "illumos")]
  25 type GetRandomFn = unsafe extern "C" fn(*mut u8, libc::size_t, libc::c_uint) -> libc::ssize_t;
  26 #[cfg(target_os = "solaris")]
  27 type GetRandomFn = unsafe extern "C" fn(*mut u8, libc::size_t, libc::c_uint) -> libc::c_int;
  28
  29 pub fn getrandom_inner(dest: &mut [u8]) -> Result<(), Error> {
  30     static GETRANDOM: Weak = unsafe { Weak::new("getrandom\0") };
  31     if let Some(fptr) = GETRANDOM.ptr() {
  32         let func: GetRandomFn = unsafe { mem::transmute(fptr) };
  33         // 256 bytes is the lowest common denominator across all the Solaris
  34         // derived platforms for atomically obtaining random data.
  35         for chunk in dest.chunks_mut(256) {
  36             sys_fill_exact(chunk, |buf| unsafe {
  37                 func(buf.as_mut_ptr(), buf.len(), 0) as libc::ssize_t
  38             })?
  39         }
  40         Ok(())
  41     } else {
  42         use_file::getrandom_inner(dest)
  43     }
  44 }