rand.rs.html -- source

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backtrace

backtrace

libunwind.rs mod.rs

symbolize

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backtrace_sys

base64

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bigtable

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cfg_if

cookie

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cookie_store

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crc32fast

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crossbeam_queue

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sync

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backoff.rs cache_padded.rs lib.rs thread.rs

curl

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error_chain

backtrace.rs error_chain.rs impl_error_chain_kind.rs lib.rs quick_main.rs

failure

backtrace

internal.rs mod.rs

error

error_impl.rs mod.rs

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failure_derive

flate2

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ffi

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zlib

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stream

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h2

http

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proto

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h2

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server

conn.rs mod.rs shutdown.rs tcp.rs

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make_service.rs mod.rs new_service.rs service.rs

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hyper_tls

client.rs lib.rs stream.rs

idna

lib.rs punycode.rs uts46.rs

indexmap

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iovec

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inline_lazy.rs lib.rs

libc

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linux

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align.rs mod.rs

align.rs mod.rs

fixed_width_ints.rs lib.rs macros.rs

libz_sys

lock_api

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log

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matches

maybe_uninit

memoffset

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mime

lib.rs parse.rs

mime_guess

impl_bin_search.rs lib.rs

miniz_oxide

deflate

buffer.rs core.rs mod.rs stream.rs

inflate

core.rs mod.rs output_buffer.rs stream.rs

lib.rs shared.rs

mio

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imp

net2

sys

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ext.rs lib.rs socket.rs tcp.rs udp.rs unix.rs utils.rs

num_cpus

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openssl

openssl_probe

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parking_lot

condvar.rs deadlock.rs elision.rs lib.rs mutex.rs once.rs raw_mutex.rs raw_rwlock.rs remutex.rs rwlock.rs util.rs

parking_lot_core

thread_parker

linux.rs mod.rs

lib.rs parking_lot.rs spinwait.rs util.rs word_lock.rs

percent_encoding

proc_macro2

fallback.rs lib.rs strnom.rs wrapper.rs

protobuf

protobuf_json

publicsuffix

errors.rs lib.rs

quote

ext.rs format.rs ident_fragment.rs lib.rs runtime.rs spanned.rs to_tokens.rs

rand

rand_chacha

chacha.rs lib.rs

rand_core

rand_hc

hc128.rs lib.rs

rand_isaac

isaac.rs isaac64.rs isaac_array.rs lib.rs

rand_jitter

dummy_log.rs error.rs lib.rs platform.rs

rand_os

dummy_log.rs lib.rs linux_android.rs random_device.rs

rand_pcg

lib.rs pcg128.rs pcg64.rs

rand_xorshift

regex

literal

backtrack.rs cache.rs compile.rs error.rs exec.rs expand.rs find_byte.rs input.rs lib.rs pikevm.rs prog.rs re_builder.rs re_bytes.rs re_set.rs re_trait.rs re_unicode.rs sparse.rs utf8.rs

regex_syntax

ast

mod.rs parse.rs print.rs visitor.rs

hir

literal

interval.rs mod.rs print.rs translate.rs visitor.rs

unicode_tables

either.rs error.rs lib.rs parser.rs unicode.rs utf8.rs

reqwest

rustc_demangle

legacy.rs lib.rs v0.rs

rustc_serialize

base64.rs collection_impls.rs hex.rs json.rs lib.rs serialize.rs

ryu

buffer

pretty

exponent.rs mantissa.rs mod.rs

common.rs d2s.rs d2s_full_table.rs d2s_intrinsics.rs digit_table.rs f2s.rs lib.rs

scopeguard

serde

de

from_primitive.rs ignored_any.rs impls.rs mod.rs utf8.rs value.rs

private

de.rs macros.rs mod.rs ser.rs

ser

impls.rs impossible.rs mod.rs

export.rs integer128.rs lib.rs macros.rs

serde_codegen_internals

ast.rs attr.rs case.rs ctxt.rs lib.rs

serde_derive

internals

ast.rs attr.rs case.rs check.rs ctxt.rs mod.rs symbol.rs

bound.rs de.rs dummy.rs fragment.rs lib.rs pretend.rs ser.rs try.rs

serde_json

value

de.rs from.rs index.rs mod.rs partial_eq.rs ser.rs

de.rs error.rs iter.rs lib.rs macros.rs map.rs number.rs read.rs ser.rs

serde_urlencoded

ser

key.rs mod.rs pair.rs part.rs value.rs

slab

smallvec

smpl_jwt

error.rs lib.rs

socket2

sys

lib.rs sockaddr.rs socket.rs utils.rs

string

syn

synom

helper.rs lib.rs space.rs

synstructure

lib.rs macros.rs

time

display.rs duration.rs lib.rs parse.rs sys.rs

tokio

executor

current_thread

reactor

mod.rs poll_evented.rs

runtime

current_thread

builder.rs mod.rs runtime.rs

threadpool

builder.rs mod.rs shutdown.rs task_executor.rs

util

enumerate.rs future.rs mod.rs stream.rs

clock.rs io.rs lib.rs net.rs prelude.rs timer.rs

tokio_buf

util

chain.rs collect.rs from.rs iter.rs limit.rs mod.rs stream.rs

lib.rs never.rs size_hint.rs str.rs u8.rs

tokio_current_thread

lib.rs scheduler.rs

tokio_executor

enter.rs error.rs executor.rs global.rs lib.rs park.rs typed.rs

tokio_io

tokio_reactor

background.rs lib.rs poll_evented.rs registration.rs sharded_rwlock.rs

tokio_sync

mpsc

block.rs bounded.rs chan.rs list.rs mod.rs unbounded.rs

task

atomic_task.rs mod.rs

lib.rs lock.rs loom.rs oneshot.rs semaphore.rs watch.rs

tokio_tcp

incoming.rs lib.rs listener.rs stream.rs

tokio_threadpool

tokio_timer

try_from

char.rs int.rs lib.rs

try_lock

unicase

unicode

ascii.rs lib.rs

unicode_bidi

char_data

mod.rs tables.rs

deprecated.rs explicit.rs format_chars.rs implicit.rs level.rs lib.rs prepare.rs

unicode_normalization

__test_api.rs decompose.rs lib.rs lookups.rs normalize.rs perfect_hash.rs quick_check.rs recompose.rs stream_safe.rs tables.rs

unicode_xid

lib.rs tables.rs

url

form_urlencoded.rs host.rs lib.rs origin.rs parser.rs path_segments.rs query_encoding.rs quirks.rs slicing.rs

uuid

adapter

core_support

parser

core_support.rs mod.rs std_support.rs

builder.rs core_support.rs lib.rs prelude.rs std_support.rs v4.rs

want

//! Utilities for secure random number generation.
//!
//! # Examples
//!
//! To generate a buffer with cryptographically strong bytes:
//!
//! ```
//! use openssl::rand::rand_bytes;
//!
//! let mut buf = [0; 256];
//! rand_bytes(&mut buf).unwrap();
//! ```
use ffi;
use libc::c_int;

use cvt;
use error::ErrorStack;

/// Fill buffer with cryptographically strong pseudo-random bytes.
///
/// This corresponds to [`RAND_bytes`].
///
/// # Examples
///
/// To generate a buffer with cryptographically strong bytes:
///
/// ```
/// use openssl::rand::rand_bytes;
///
/// let mut buf = [0; 256];
/// rand_bytes(&mut buf).unwrap();
/// ```
///
/// [`RAND_bytes`]: https://www.openssl.org/docs/man1.1.0/crypto/RAND_bytes.html
pub fn rand_bytes(buf: &mut [u8]) -> Result<(), ErrorStack> {
    unsafe {
        ffi::init();
        assert!(buf.len() <= c_int::max_value() as usize);
        cvt(ffi::RAND_bytes(buf.as_mut_ptr(), buf.len() as c_int)).map(|_| ())
    }
}

/// Controls random device file descriptor behavior.
///
/// Requires OpenSSL 1.1.1 or newer.
///
/// This corresponds to [`RAND_keep_random_devices_open`].
///
/// [`RAND_keep_random_devices_open`]: https://www.openssl.org/docs/manmaster/man3/RAND_keep_random_devices_open.html
#[cfg(ossl111)]
pub fn keep_random_devices_open(keep: bool) {
    unsafe {
        ffi::RAND_keep_random_devices_open(keep as c_int);
    }
}

#[cfg(test)]
mod tests {
    use super::rand_bytes;

    #[test]
    fn test_rand_bytes() {
        let mut buf = [0; 32];
        rand_bytes(&mut buf).unwrap();
    }
}