| //! Random data generation with `arc4random_buf`. | |
| //! | |
| //! Contrary to its name, `arc4random` doesn't actually use the horribly-broken | |
| //! RC4 cypher anymore, at least not on modern systems, but rather something | |
| //! like ChaCha20 with continual reseeding from the OS. That makes it an ideal | |
| //! source of large quantities of cryptographically secure data, which is exactly | |
| //! what we need for `DefaultRandomSource`. Unfortunately, it's not available | |
| //! on all UNIX systems, most notably Linux (until recently, but it's just a | |
| //! wrapper for `getrandom`. Since we need to hook into `getrandom` directly | |
| //! for `HashMap` keys anyway, we just keep our version). | |
| #[cfg(not(any( | |
| target_os = "haiku", | |
| target_os = "illumos", | |
| target_os = "solaris", | |
| target_os = "vita", | |
| )))] | |
| use libc::arc4random_buf; | |
| // FIXME: move these to libc (except Haiku, that one needs to link to libbsd.so). | |
| #[cfg(any( | |
| target_os = "haiku", // See https://git.haiku-os.org/haiku/tree/headers/compatibility/bsd/stdlib.h | |
| target_os = "illumos", // See https://www.illumos.org/man/3C/arc4random | |
| target_os = "solaris", // See https://docs.oracle.com/cd/E88353_01/html/E37843/arc4random-3c.html | |
| target_os = "vita", // See https://github.com/vitasdk/newlib/blob/b89e5bc183b516945f9ee07eef483ecb916e45ff/newlib/libc/include/stdlib.h#L74 | |
| ))] | |
| #[cfg_attr(target_os = "haiku", link(name = "bsd"))] | |
| unsafe extern "C" { | |
| fn arc4random_buf(buf: *mut core::ffi::c_void, nbytes: libc::size_t); | |
| } | |
| pub fn fill_bytes(bytes: &mut [u8]) { | |
| unsafe { arc4random_buf(bytes.as_mut_ptr().cast(), bytes.len()) } | |
| } |