1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
|
//! Implementation for Linux / Android
use crate::{
lazy::LazyBool,
util_libc::{last_os_error, sys_fill_exact},
{use_file, Error},
};
use core::mem::MaybeUninit;
pub fn getrandom_inner(dest: &mut [MaybeUninit<u8>]) -> Result<(), Error> {
// getrandom(2) was introduced in Linux 3.17
static HAS_GETRANDOM: LazyBool = LazyBool::new();
if HAS_GETRANDOM.unsync_init(is_getrandom_available) {
sys_fill_exact(dest, |buf| unsafe {
getrandom(buf.as_mut_ptr() as *mut libc::c_void, buf.len(), 0)
})
} else {
use_file::getrandom_inner(dest)
}
}
fn is_getrandom_available() -> bool {
let res = unsafe { getrandom(core::ptr::null_mut(), 0, libc::GRND_NONBLOCK) };
if res < 0 {
match last_os_error().raw_os_error() {
Some(libc::ENOSYS) => false, // No kernel support
Some(libc::EPERM) => false, // Blocked by seccomp
_ => true,
}
} else {
true
}
}
unsafe fn getrandom(
buf: *mut libc::c_void,
buflen: libc::size_t,
flags: libc::c_uint,
) -> libc::ssize_t {
libc::syscall(libc::SYS_getrandom, buf, buflen, flags) as libc::ssize_t
}
|
