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//! Implementation for the Solaris family
//!
//! `/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` (and use GRND_RANDOM).
//!
//! Solaris 11.3 and late-2018 illumos added the getrandom(2) libc function.
//! To make sure we can compile on both Solaris and its derivatives, as well as
//! function, we check for the existence of getrandom(2) in libc by calling
//! libc::dlsym.
use crate::{
use_file,
util_libc::{sys_fill_exact, Weak},
Error,
};
use core::mem::{self, MaybeUninit};
static GETRANDOM: Weak = unsafe { Weak::new("getrandom\0") };
type GetRandomFn =
unsafe extern "C" fn(*mut libc::c_void, libc::size_t, libc::c_uint) -> libc::ssize_t;
pub fn getrandom_inner(dest: &mut [MaybeUninit<u8>]) -> Result<(), Error> {
if let Some(fptr) = GETRANDOM.ptr() {
let func: GetRandomFn = unsafe { mem::transmute(fptr) };
// 256 bytes is the lowest common denominator across all the Solaris
// derived platforms for atomically obtaining random data.
for chunk in dest.chunks_mut(256) {
sys_fill_exact(chunk, |buf| unsafe {
// A cast is needed for the flags as libc uses the wrong type.
func(
buf.as_mut_ptr() as *mut libc::c_void,
buf.len(),
libc::GRND_RANDOM as libc::c_uint,
)
})?
}
Ok(())
} else {
use_file::getrandom_inner(dest)
}
}
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