| // Copyright 2019 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 macOS |
| use crate::util_libc::{last_os_error, Weak}; |
| use crate::{use_file, Error}; |
| use core::mem; |
| |
| type GetEntropyFn = unsafe extern "C" fn(*mut u8, libc::size_t) -> libc::c_int; |
| |
| pub fn getrandom_inner(dest: &mut [u8]) -> Result<(), Error> { |
| static GETENTROPY: Weak = unsafe { Weak::new("getentropy\0") }; |
| if let Some(fptr) = GETENTROPY.ptr() { |
| let func: GetEntropyFn = unsafe { mem::transmute(fptr) }; |
| for chunk in dest.chunks_mut(256) { |
| let ret = unsafe { func(chunk.as_mut_ptr(), chunk.len()) }; |
| if ret != 0 { |
| let err = last_os_error(); |
| error!("getentropy syscall failed"); |
| return Err(err); |
| } |
| } |
| Ok(()) |
| } else { |
| // We fallback to reading from /dev/random instead of SecRandomCopyBytes |
| // to avoid high startup costs and linking the Security framework. |
| use_file::getrandom_inner(dest) |
| } |
| } |
