1 //! Implementation for ESP-IDF
2 use crate::Error;
3 use core::{ffi::c_void, mem::MaybeUninit};
4 
5 extern "C" {
esp_fill_random(buf: *mut c_void, len: usize) -> u326     fn esp_fill_random(buf: *mut c_void, len: usize) -> u32;
7 }
8 
getrandom_inner(dest: &mut [MaybeUninit<u8>]) -> Result<(), Error>9 pub fn getrandom_inner(dest: &mut [MaybeUninit<u8>]) -> Result<(), Error> {
10     // Not that NOT enabling WiFi, BT, or the voltage noise entropy source (via `bootloader_random_enable`)
11     // will cause ESP-IDF to return pseudo-random numbers based on the voltage noise entropy, after the initial boot process:
12     // https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/system/random.html
13     //
14     // However tracking if some of these entropy sources is enabled is way too difficult to implement here
15     unsafe { esp_fill_random(dest.as_mut_ptr().cast(), dest.len()) };
16 
17     Ok(())
18 }
19