src/backend/libc/rand/syscalls.rs

//! libc syscalls supporting `rustix::rand`.

#[cfg(linux_kernel)]
use {crate::backend::c, crate::backend::conv::ret_usize, crate::io, crate::rand::GetRandomFlags};

#[cfg(linux_kernel)]
pub(crate) unsafe fn getrandom(
    buf: *mut u8,
    cap: usize,
    flags: GetRandomFlags,
) -> io::Result<usize> {
    // `getrandom` wasn't supported in glibc until 2.25.
    weak_or_syscall! {
        fn getrandom(buf: *mut c::c_void, buflen: c::size_t, flags: c::c_uint) via SYS_getrandom -> c::ssize_t
    }

    ret_usize(getrandom(buf.cast(), cap, flags.bits()))
}