1//! libc syscalls supporting `rustix::rand`.
2
3#[cfg(target_os = "linux")]
4use {super::super::c, super::super::conv::ret_ssize_t, crate::io, crate::rand::GetRandomFlags};
5
6#[cfg(target_os = "linux")]
7pub(crate) fn getrandom(buf: &mut [u8], flags: GetRandomFlags) -> io::Result<usize> {
8    // `getrandom` wasn't supported in glibc until 2.25.
9    weak_or_syscall! {
10        fn getrandom(buf: *mut c::c_void, buflen: c::size_t, flags: c::c_uint) via SYS_getrandom -> c::ssize_t
11    }
12
13    let nread =
14        unsafe { ret_ssize_t(getrandom(buf.as_mut_ptr().cast(), buf.len(), flags.bits()))? };
15    Ok(nread as usize)
16}
17