1//! Utilities for secure random number generation.
2//!
3//! # Examples
4//!
5//! To generate a buffer with cryptographically strong bytes:
6//!
7//! ```
8//! use openssl::rand::rand_bytes;
9//!
10//! let mut buf = [0; 256];
11//! rand_bytes(&mut buf).unwrap();
12//! ```
13use libc::c_int;
14
15use crate::error::ErrorStack;
16use crate::{cvt, LenType};
17use openssl_macros::corresponds;
18
19/// Fill buffer with cryptographically strong pseudo-random bytes.
20///
21/// # Examples
22///
23/// To generate a buffer with cryptographically strong random bytes:
24///
25/// ```
26/// use openssl::rand::rand_bytes;
27///
28/// let mut buf = [0; 256];
29/// rand_bytes(&mut buf).unwrap();
30/// ```
31#[corresponds(RAND_bytes)]
32pub fn rand_bytes(buf: &mut [u8]) -> Result<(), ErrorStack> {
33    unsafe {
34        ffi::init();
35        assert!(buf.len() <= c_int::max_value() as usize);
36        cvt(ffi::RAND_bytes(buf.as_mut_ptr(), buf.len() as LenType)).map(|_| ())
37    }
38}
39
40/// Controls random device file descriptor behavior.
41///
42/// Requires OpenSSL 1.1.1 or newer.
43#[corresponds(RAND_keep_random_devices_open)]
44#[cfg(ossl111)]
45pub fn keep_random_devices_open(keep: bool) {
46    unsafe {
47        ffi::RAND_keep_random_devices_open(keep as LenType);
48    }
49}
50
51#[cfg(test)]
52mod tests {
53    use super::rand_bytes;
54
55    #[test]
56    fn test_rand_bytes() {
57        let mut buf = [0; 32];
58        rand_bytes(&mut buf).unwrap();
59    }
60}
61