| // Copyright 2021 Developers of the Rand project. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // https://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| //! Implementation for ESP-IDF |
| use crate::Error; |
| use core::ffi::c_void; |
| |
| extern "C" { |
| fn esp_fill_random(buf: *mut c_void, len: usize) -> u32; |
| } |
| |
| pub fn getrandom_inner(dest: &mut [u8]) -> Result<(), Error> { |
| // Not that NOT enabling WiFi, BT, or the voltage noise entropy source (via `bootloader_random_enable`) |
| // will cause ESP-IDF to return pseudo-random numbers based on the voltage noise entropy, after the initial boot process: |
| // https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/system/random.html |
| // |
| // However tracking if some of these entropy sources is enabled is way too difficult to implement here |
| unsafe { esp_fill_random(dest.as_mut_ptr().cast(), dest.len()) }; |
| |
| Ok(()) |
| } |
