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|
//! Implementation for FreeBSD and NetBSD
use crate::{
util_libc::{sys_fill_exact, Weak},
Error,
};
use core::{mem::MaybeUninit, ptr};
fn kern_arnd(buf: &mut [MaybeUninit<u8>]) -> libc::ssize_t {
static MIB: [libc::c_int; 2] = [libc::CTL_KERN, libc::KERN_ARND];
let mut len = buf.len();
let ret = unsafe {
libc::sysctl(
MIB.as_ptr(),
MIB.len() as libc::c_uint,
buf.as_mut_ptr() as *mut _,
&mut len,
ptr::null(),
0,
)
};
if ret == -1 {
-1
} else {
len as libc::ssize_t
}
}
type GetRandomFn = unsafe extern "C" fn(*mut u8, libc::size_t, libc::c_uint) -> libc::ssize_t;
pub fn getrandom_inner(dest: &mut [MaybeUninit<u8>]) -> Result<(), Error> {
// getrandom(2) was introduced in FreeBSD 12.0 and NetBSD 10.0
static GETRANDOM: Weak = unsafe { Weak::new("getrandom\0") };
if let Some(fptr) = GETRANDOM.ptr() {
let func: GetRandomFn = unsafe { core::mem::transmute(fptr) };
return sys_fill_exact(dest, |buf| unsafe {
func(buf.as_mut_ptr() as *mut u8, buf.len(), 0)
});
}
// Both FreeBSD and NetBSD will only return up to 256 bytes at a time, and
// older NetBSD kernels will fail on longer buffers.
for chunk in dest.chunks_mut(256) {
sys_fill_exact(chunk, kern_arnd)?
}
Ok(())
}
|
