| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `/root/.cargo/registry/src/github.com-1ecc6299db9ec823/rdrand-0.8.2/src/lib.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>lib.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../normalize.css"><link rel="stylesheet" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../ayu.css" disabled><link rel="stylesheet" href="../../dark.css" disabled><link rel="stylesheet" href="../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../storage.js"></script><script defer src="../../source-script.js"></script><script defer src="../../source-files.js"></script><script defer src="../../main.js"></script><noscript><link rel="stylesheet" href="../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../rdrand/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../rdrand/index.html"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><span id="1">1</span> |
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| <span id="523">523</span> |
| <span id="524">524</span> |
| <span id="525">525</span> |
| <span id="526">526</span> |
| <span id="527">527</span> |
| <span id="528">528</span> |
| <span id="529">529</span> |
| <span id="530">530</span> |
| <span id="531">531</span> |
| <span id="532">532</span> |
| <span id="533">533</span> |
| <span id="534">534</span> |
| <span id="535">535</span> |
| <span id="536">536</span> |
| <span id="537">537</span> |
| <span id="538">538</span> |
| <span id="539">539</span> |
| <span id="540">540</span> |
| <span id="541">541</span> |
| <span id="542">542</span> |
| <span id="543">543</span> |
| <span id="544">544</span> |
| <span id="545">545</span> |
| <span id="546">546</span> |
| <span id="547">547</span> |
| <span id="548">548</span> |
| <span id="549">549</span> |
| <span id="550">550</span> |
| <span id="551">551</span> |
| <span id="552">552</span> |
| <span id="553">553</span> |
| <span id="554">554</span> |
| <span id="555">555</span> |
| <span id="556">556</span> |
| <span id="557">557</span> |
| </pre><pre class="rust"><code><span class="comment">// Copyright © 2014, Simonas Kazlauskas <rdrand@kazlauskas.me> |
| // |
| // Permission to use, copy, modify, and/or distribute this software for any purpose with or without |
| // fee is hereby granted, provided that the above copyright notice and this permission notice |
| // appear in all copies. |
| // |
| // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS |
| // SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE |
| // AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| // WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, |
| // NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE |
| // OF THIS SOFTWARE. |
| </span><span class="doccomment">//! An implementation of random number generators based on `rdrand` and `rdseed` instructions. |
| //! |
| //! The random number generators provided by this crate are fairly slow (the latency for these |
| //! instructions is pretty high), but provide high quality random bits. Caveat is: neither AMD’s |
| //! nor Intel’s designs are public and therefore are not verifiable for lack of backdoors. |
| //! |
| //! Unless you know what you are doing, use the random number generators provided by the `rand` |
| //! crate (such as `OsRng`) instead. |
| //! |
| //! Here are a measurements for select processor architectures. Check [Agner’s instruction tables] |
| //! for up-to-date listings. |
| //! |
| //! <table> |
| //! <tr> |
| //! <th>Architecture</th> |
| //! <th colspan="3">Latency (cycles)</th> |
| //! <th>Maximum throughput (per core)</th> |
| //! </tr> |
| //! <tr> |
| //! <td></td> |
| //! <td>u16</td> |
| //! <td>u32</td> |
| //! <td>u64</td> |
| //! <td></td> |
| //! </tr> |
| //! <tr> |
| //! <td>AMD Ryzen</td> |
| //! <td>~1200</td> |
| //! <td>~1200</td> |
| //! <td>~2500</td> |
| //! <td>~12MB/s @ 3.7GHz</td> |
| //! </tr> |
| //! <tr> |
| //! <td>Intel Skylake</td> |
| //! <td>460</td> |
| //! <td>460</td> |
| //! <td>460</td> |
| //! <td>~72MB/s @ 4.2GHz</td> |
| //! </tr> |
| //! <tr> |
| //! <td>Intel Haswell</td> |
| //! <td>320</td> |
| //! <td>320</td> |
| //! <td>320</td> |
| //! <td>~110MB/s @ 4.4GHz</td> |
| //! </tr> |
| //! </table> |
| //! |
| //! [Agner’s instruction tables]: http://agner.org/optimize/ |
| </span><span class="attribute">#![cfg_attr(not(feature = <span class="string">"std"</span>), no_std)] |
| |
| </span><span class="kw">pub mod </span>changelog; |
| <span class="kw">mod </span>errors; |
| |
| <span class="kw">pub use </span>errors::ErrorCode; |
| <span class="kw">use </span>rand_core::{CryptoRng, Error, RngCore}; |
| |
| <span class="attribute">#[cold] |
| #[inline(never)] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>busy_loop_fail(code: ErrorCode) -> ! { |
| <span class="macro">panic!</span>(<span class="string">"{}"</span>, code); |
| } |
| |
| <span class="doccomment">/// A cryptographically secure statistically uniform, non-periodic and non-deterministic random bit |
| /// generator. |
| /// |
| /// Note that this generator may be implemented using a deterministic algorithm that is reseeded |
| /// routinely from a non-deterministic entropy source to achieve the desirable properties. |
| /// |
| /// This generator is a viable replacement to any generator, however, since nobody has audited |
| /// this hardware implementation yet, the usual disclaimers as to their suitability apply. |
| /// |
| /// It is potentially faster than `OsRng`, but is only supported by more recent architectures such |
| /// as Intel Ivy Bridge and AMD Zen. |
| </span><span class="attribute">#[derive(Clone, Copy)] |
| </span><span class="kw">pub struct </span>RdRand(()); |
| |
| <span class="doccomment">/// A cryptographically secure non-deterministic random bit generator. |
| /// |
| /// This generator produces high-entropy output and is suited to seed other pseudo-random |
| /// generators. |
| /// |
| /// This instruction is only supported by recent architectures such as Intel Broadwell and AMD Zen. |
| /// |
| /// This generator is not intended for general random number generation purposes and should be used |
| /// to seed other generators implementing [rand_core::SeedableRng]. |
| </span><span class="attribute">#[derive(Clone, Copy)] |
| </span><span class="kw">pub struct </span>RdSeed(()); |
| |
| <span class="kw">impl </span>CryptoRng <span class="kw">for </span>RdRand {} |
| <span class="kw">impl </span>CryptoRng <span class="kw">for </span>RdSeed {} |
| |
| <span class="kw">mod </span>arch { |
| <span class="attribute">#[cfg(target_arch = <span class="string">"x86"</span>)] |
| </span><span class="kw">pub use </span>core::arch::x86::<span class="kw-2">*</span>; |
| <span class="attribute">#[cfg(target_arch = <span class="string">"x86_64"</span>)] |
| </span><span class="kw">pub use </span>core::arch::x86_64::<span class="kw-2">*</span>; |
| |
| <span class="attribute">#[cfg(target_arch = <span class="string">"x86"</span>)] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">unsafe fn </span>_rdrand64_step(dest: <span class="kw-2">&mut </span>u64) -> i32 { |
| <span class="kw">let </span><span class="kw-2">mut </span>ret1: u32 = <span class="number">0</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>ret2: u32 = <span class="number">0</span>; |
| <span class="kw">let </span>ok = _rdrand32_step(<span class="kw-2">&mut </span>ret1) & _rdrand32_step(<span class="kw-2">&mut </span>ret2); |
| <span class="kw-2">*</span>dest = (ret1 <span class="kw">as </span>u64) << <span class="number">32 </span>| (ret2 <span class="kw">as </span>u64); |
| ok |
| } |
| |
| <span class="attribute">#[cfg(target_arch = <span class="string">"x86"</span>)] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">unsafe fn </span>_rdseed64_step(dest: <span class="kw-2">&mut </span>u64) -> i32 { |
| <span class="kw">let </span><span class="kw-2">mut </span>ret1: u32 = <span class="number">0</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>ret2: u32 = <span class="number">0</span>; |
| <span class="kw">let </span>ok = _rdseed32_step(<span class="kw-2">&mut </span>ret1) & _rdseed32_step(<span class="kw-2">&mut </span>ret2); |
| <span class="kw-2">*</span>dest = (ret1 <span class="kw">as </span>u64) << <span class="number">32 </span>| (ret2 <span class="kw">as </span>u64); |
| ok |
| } |
| } |
| |
| <span class="comment">// See the following documentation for usage (in particular wrt retries) recommendations: |
| // |
| // https://software.intel.com/content/www/us/en/develop/articles/intel-digital-random-number-generator-drng-software-implementation-guide.html |
| </span><span class="macro">macro_rules! </span>loop_rand { |
| (<span class="string">"rdrand"</span>, <span class="macro-nonterminal">$el</span>: ty, <span class="macro-nonterminal">$step</span>: path) => {{ |
| <span class="kw">let </span><span class="kw-2">mut </span>idx = <span class="number">0</span>; |
| <span class="kw">loop </span>{ |
| <span class="kw">let </span><span class="kw-2">mut </span>el: <span class="macro-nonterminal">$el </span>= <span class="number">0</span>; |
| <span class="kw">if </span><span class="macro-nonterminal">$step</span>(<span class="kw-2">&mut </span>el) != <span class="number">0 </span>{ |
| <span class="kw">break </span><span class="prelude-val">Ok</span>(el); |
| } <span class="kw">else if </span>idx == <span class="number">10 </span>{ |
| <span class="kw">break </span><span class="prelude-val">Err</span>(ErrorCode::HardwareFailure); |
| } |
| idx += <span class="number">1</span>; |
| } |
| }}; |
| (<span class="string">"rdseed"</span>, <span class="macro-nonterminal">$el</span>: ty, <span class="macro-nonterminal">$step</span>: path) => {{ |
| <span class="kw">let </span><span class="kw-2">mut </span>idx = <span class="number">0</span>; |
| <span class="kw">loop </span>{ |
| <span class="kw">let </span><span class="kw-2">mut </span>el: <span class="macro-nonterminal">$el </span>= <span class="number">0</span>; |
| <span class="kw">if </span><span class="macro-nonterminal">$step</span>(<span class="kw-2">&mut </span>el) != <span class="number">0 </span>{ |
| <span class="kw">break </span><span class="prelude-val">Ok</span>(el); |
| } <span class="kw">else if </span>idx == <span class="number">127 </span>{ |
| <span class="kw">break </span><span class="prelude-val">Err</span>(ErrorCode::HardwareFailure); |
| } |
| idx += <span class="number">1</span>; |
| arch::_mm_pause(); |
| } |
| }}; |
| } |
| |
| <span class="attribute">#[inline(always)] |
| </span><span class="kw">fn </span>authentic_amd() -> bool { |
| <span class="kw">let </span>cpuid0 = <span class="kw">unsafe </span>{ arch::__cpuid(<span class="number">0</span>) }; |
| <span class="macro">matches!</span>( |
| (cpuid0.ebx, cpuid0.ecx, cpuid0.edx), |
| (<span class="number">0x68747541</span>, <span class="number">0x444D4163</span>, <span class="number">0x69746E65</span>) |
| ) |
| } |
| |
| <span class="attribute">#[inline(always)] |
| </span><span class="kw">fn </span>amd_family(cpuid1: <span class="kw-2">&</span>arch::CpuidResult) -> u32 { |
| ((cpuid1.eax >> <span class="number">8</span>) & <span class="number">0xF</span>) + ((cpuid1.eax >> <span class="number">20</span>) & <span class="number">0xFF</span>) |
| } |
| |
| <span class="attribute">#[inline(always)] |
| </span><span class="kw">fn </span>has_rdrand(cpuid1: <span class="kw-2">&</span>arch::CpuidResult) -> bool { |
| <span class="kw">const </span>FLAG: u32 = <span class="number">1 </span><< <span class="number">30</span>; |
| cpuid1.ecx & FLAG == FLAG |
| } |
| |
| <span class="attribute">#[inline(always)] |
| </span><span class="kw">fn </span>has_rdseed() -> bool { |
| <span class="kw">const </span>FLAG: u32 = <span class="number">1 </span><< <span class="number">18</span>; |
| <span class="kw">unsafe </span>{ arch::__cpuid(<span class="number">7</span>).ebx & FLAG == FLAG } |
| } |
| |
| <span class="doccomment">/// NB: On AMD processor families < 0x17, we want to unconditionally disable RDRAND |
| /// and RDSEED. Executing these instructions on these processors can return |
| /// non-random data (0) while also reporting a success. |
| /// |
| /// See: |
| /// * https://github.com/systemd/systemd/issues/11810 |
| /// * https://lore.kernel.org/all/776cb5c2d33e7fd0d2893904724c0e52b394f24a.1565817448.git.thomas.lendacky@amd.com/ |
| /// |
| /// We take extra care to do so even if `-Ctarget-features=+rdrand` have been |
| /// specified, in order to prevent users from shooting themselves in their feet. |
| </span><span class="kw">const </span>FIRST_GOOD_AMD_FAMILY: u32 = <span class="number">0x17</span>; |
| |
| <span class="macro">macro_rules! </span>is_available { |
| (<span class="string">"rdrand"</span>) => {{ |
| <span class="kw">if </span>authentic_amd() { |
| <span class="kw">let </span>cpuid1 = <span class="kw">unsafe </span>{ arch::__cpuid(<span class="number">1</span>) }; |
| has_rdrand(<span class="kw-2">&</span>cpuid1) && amd_family(<span class="kw-2">&</span>cpuid1) >= FIRST_GOOD_AMD_FAMILY |
| } <span class="kw">else </span>{ |
| <span class="macro">cfg!</span>(target_feature = <span class="string">"rdrand"</span>) || has_rdrand(<span class="kw-2">&</span><span class="kw">unsafe </span>{ arch::__cpuid(<span class="number">1</span>) }) |
| } |
| }}; |
| (<span class="string">"rdseed"</span>) => {{ |
| <span class="kw">if </span>authentic_amd() { |
| amd_family(<span class="kw-2">&</span><span class="kw">unsafe </span>{ arch::__cpuid(<span class="number">1</span>) }) >= FIRST_GOOD_AMD_FAMILY && has_rdseed() |
| } <span class="kw">else </span>{ |
| <span class="macro">cfg!</span>(target_feature = <span class="string">"rdrand"</span>) || has_rdseed() |
| } |
| }}; |
| } |
| |
| <span class="macro">macro_rules! </span>impl_rand { |
| (<span class="macro-nonterminal">$gen</span>:ident, <span class="macro-nonterminal">$feat</span>:tt, <span class="macro-nonterminal">$step16</span>: path, <span class="macro-nonterminal">$step32</span>:path, <span class="macro-nonterminal">$step64</span>:path, |
| maxstep = <span class="macro-nonterminal">$maxstep</span>:path, maxty = <span class="macro-nonterminal">$maxty</span>: ty) => { |
| <span class="kw">impl </span><span class="macro-nonterminal">$gen </span>{ |
| <span class="doccomment">/// Create a new instance of the random number generator. |
| /// |
| /// This constructor checks whether the CPU the program is running on supports the |
| /// instruction necessary for this generator to operate. If the instruction is not |
| /// supported, an error is returned. |
| </span><span class="kw">pub fn </span>new() -> <span class="prelude-ty">Result</span><<span class="self">Self</span>, ErrorCode> { |
| <span class="kw">if </span><span class="macro">cfg!</span>(target_env = <span class="string">"sgx"</span>) { |
| <span class="kw">if </span><span class="macro">cfg!</span>(target_feature = <span class="macro-nonterminal">$feat</span>) { |
| <span class="prelude-val">Ok</span>(<span class="macro-nonterminal">$gen</span>(())) |
| } <span class="kw">else </span>{ |
| <span class="prelude-val">Err</span>(ErrorCode::UnsupportedInstruction) |
| } |
| } <span class="kw">else if </span><span class="macro">is_available!</span>(<span class="macro-nonterminal">$feat</span>) { |
| <span class="prelude-val">Ok</span>(<span class="macro-nonterminal">$gen</span>(())) |
| } <span class="kw">else </span>{ |
| <span class="prelude-val">Err</span>(ErrorCode::UnsupportedInstruction) |
| } |
| } |
| |
| <span class="doccomment">/// Generate a single random `u16` value. |
| /// |
| /// The underlying instruction may fail for variety reasons (such as actual hardware |
| /// failure or exhausted entropy), however the exact reason for the failure is not |
| /// usually exposed. |
| /// |
| /// This method will retry calling the instruction a few times, however if all the |
| /// attempts fail, it will return `None`. |
| /// |
| /// In case `Err` is returned, the caller should assume that a non-recoverable failure |
| /// has occured and use another random number genrator instead. |
| </span><span class="attribute">#[inline(always)] |
| </span><span class="kw">pub fn </span>try_next_u16(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Result</span><u16, ErrorCode> { |
| <span class="attribute">#[target_feature(enable = <span class="macro-nonterminal">$feat</span>)] |
| </span><span class="kw">unsafe fn </span>imp() -> <span class="prelude-ty">Result</span><u16, ErrorCode> { |
| <span class="macro">loop_rand!</span>(<span class="macro-nonterminal">$feat</span>, u16, <span class="macro-nonterminal">$step16</span>) |
| } |
| <span class="kw">unsafe </span>{ imp() } |
| } |
| |
| <span class="doccomment">/// Generate a single random `u32` value. |
| /// |
| /// The underlying instruction may fail for variety reasons (such as actual hardware |
| /// failure or exhausted entropy), however the exact reason for the failure is not |
| /// usually exposed. |
| /// |
| /// This method will retry calling the instruction a few times, however if all the |
| /// attempts fail, it will return `None`. |
| /// |
| /// In case `Err` is returned, the caller should assume that a non-recoverable failure |
| /// has occured and use another random number genrator instead. |
| </span><span class="attribute">#[inline(always)] |
| </span><span class="kw">pub fn </span>try_next_u32(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Result</span><u32, ErrorCode> { |
| <span class="attribute">#[target_feature(enable = <span class="macro-nonterminal">$feat</span>)] |
| </span><span class="kw">unsafe fn </span>imp() -> <span class="prelude-ty">Result</span><u32, ErrorCode> { |
| <span class="macro">loop_rand!</span>(<span class="macro-nonterminal">$feat</span>, u32, <span class="macro-nonterminal">$step32</span>) |
| } |
| <span class="kw">unsafe </span>{ imp() } |
| } |
| |
| <span class="doccomment">/// Generate a single random `u64` value. |
| /// |
| /// The underlying instruction may fail for variety reasons (such as actual hardware |
| /// failure or exhausted entropy), however the exact reason for the failure is not |
| /// usually exposed. |
| /// |
| /// This method will retry calling the instruction a few times, however if all the |
| /// attempts fail, it will return `None`. |
| /// |
| /// In case `Err` is returned, the caller should assume that a non-recoverable failure |
| /// has occured and use another random number genrator instead. |
| /// |
| /// Note, that on 32-bit targets, there’s no underlying instruction to generate a |
| /// 64-bit number, so it is emulated with the 32-bit version of the instruction. |
| </span><span class="attribute">#[inline(always)] |
| </span><span class="kw">pub fn </span>try_next_u64(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Result</span><u64, ErrorCode> { |
| <span class="attribute">#[target_feature(enable = <span class="macro-nonterminal">$feat</span>)] |
| </span><span class="kw">unsafe fn </span>imp() -> <span class="prelude-ty">Result</span><u64, ErrorCode> { |
| <span class="macro">loop_rand!</span>(<span class="macro-nonterminal">$feat</span>, u64, <span class="macro-nonterminal">$step64</span>) |
| } |
| <span class="kw">unsafe </span>{ imp() } |
| } |
| |
| <span class="doccomment">/// Fill a buffer `dest` with random data. |
| /// |
| /// This method will use the most appropriate variant of the instruction available on |
| /// the machine to achieve the greatest single-core throughput, however it has a |
| /// slightly higher setup cost than the plain `next_u32` or `next_u64` methods. |
| /// |
| /// The underlying instruction may fail for variety reasons (such as actual hardware |
| /// failure or exhausted entropy), however the exact reason for the failure is not |
| /// usually exposed. |
| /// |
| /// This method will retry calling the instruction a few times, however if all the |
| /// attempts fail, it will return an error. |
| /// |
| /// If an error is returned, the caller should assume that an non-recoverable hardware |
| /// failure has occured and use another random number genrator instead. |
| </span><span class="attribute">#[inline(always)] |
| </span><span class="kw">pub fn </span>try_fill_bytes(<span class="kw-2">&mut </span><span class="self">self</span>, dest: <span class="kw-2">&mut </span>[u8]) -> <span class="prelude-ty">Result</span><(), ErrorCode> { |
| <span class="attribute">#[target_feature(enable = <span class="macro-nonterminal">$feat</span>)] |
| </span><span class="kw">unsafe fn </span>imp(dest: <span class="kw-2">&mut </span>[u8]) -> <span class="prelude-ty">Result</span><(), ErrorCode> { |
| <span class="kw">fn </span>slow_fill_bytes<<span class="lifetime">'a</span>>( |
| <span class="kw-2">mut </span>left: <span class="kw-2">&</span><span class="lifetime">'a </span><span class="kw-2">mut </span>[u8], |
| <span class="kw-2">mut </span>right: <span class="kw-2">&</span><span class="lifetime">'a </span><span class="kw-2">mut </span>[u8], |
| ) -> <span class="prelude-ty">Result</span><(), ErrorCode> { |
| <span class="kw">let </span><span class="kw-2">mut </span>word; |
| <span class="kw">let </span><span class="kw-2">mut </span>buffer: <span class="kw-2">&</span>[u8] = <span class="kw-2">&</span>[]; |
| <span class="kw">loop </span>{ |
| <span class="kw">if </span>left.is_empty() { |
| <span class="kw">if </span>right.is_empty() { |
| <span class="kw">break</span>; |
| } |
| ::core::mem::swap(<span class="kw-2">&mut </span>left, <span class="kw-2">&mut </span>right); |
| } |
| <span class="kw">if </span>buffer.is_empty() { |
| word = |
| <span class="kw">unsafe </span>{ <span class="macro">loop_rand!</span>(<span class="macro-nonterminal">$feat</span>, <span class="macro-nonterminal">$maxty</span>, <span class="macro-nonterminal">$maxstep</span>) }<span class="question-mark">?</span>.to_ne_bytes(); |
| buffer = <span class="kw-2">&</span>word[..]; |
| } |
| <span class="kw">let </span>len = left.len().min(buffer.len()); |
| <span class="kw">let </span>(copy_src, leftover) = buffer.split_at(len); |
| <span class="kw">let </span>(copy_dest, dest_leftover) = { left }.split_at_mut(len); |
| buffer = leftover; |
| left = dest_leftover; |
| copy_dest.copy_from_slice(copy_src); |
| } |
| <span class="prelude-val">Ok</span>(()) |
| } |
| |
| <span class="kw">let </span>destlen = dest.len(); |
| <span class="kw">if </span>destlen > ::core::mem::size_of::<<span class="macro-nonterminal">$maxty</span>>() { |
| <span class="kw">let </span>(left, mid, right) = dest.align_to_mut(); |
| <span class="kw">for </span>el <span class="kw">in </span>mid { |
| <span class="kw-2">*</span>el = <span class="macro">loop_rand!</span>(<span class="macro-nonterminal">$feat</span>, <span class="macro-nonterminal">$maxty</span>, <span class="macro-nonterminal">$maxstep</span>)<span class="question-mark">?</span>; |
| } |
| |
| slow_fill_bytes(left, right) |
| } <span class="kw">else </span>{ |
| slow_fill_bytes(dest, <span class="kw-2">&mut </span>[]) |
| } |
| } |
| <span class="kw">unsafe </span>{ imp(dest) } |
| } |
| } |
| |
| <span class="kw">impl </span>RngCore <span class="kw">for </span><span class="macro-nonterminal">$gen </span>{ |
| <span class="doccomment">/// Generate a single random `u32` value. |
| /// |
| /// The underlying instruction may fail for variety reasons (such as actual hardware |
| /// failure or exhausted entropy), however the exact reason for the failure is not |
| /// usually exposed. |
| /// |
| /// # Panic |
| /// |
| /// This method will retry calling the instruction a few times, however if all the |
| /// attempts fail, it will `panic`. |
| /// |
| /// In case `panic` occurs, the caller should assume that an non-recoverable |
| /// hardware failure has occured and use another random number genrator instead. |
| </span><span class="attribute">#[inline(always)] |
| </span><span class="kw">fn </span>next_u32(<span class="kw-2">&mut </span><span class="self">self</span>) -> u32 { |
| <span class="kw">match </span><span class="self">self</span>.try_next_u32() { |
| <span class="prelude-val">Ok</span>(result) => result, |
| <span class="prelude-val">Err</span>(c) => busy_loop_fail(c), |
| } |
| } |
| |
| <span class="doccomment">/// Generate a single random `u64` value. |
| /// |
| /// The underlying instruction may fail for variety reasons (such as actual hardware |
| /// failure or exhausted entropy), however the exact reason for the failure is not |
| /// usually exposed. |
| /// |
| /// Note, that on 32-bit targets, there’s no underlying instruction to generate a |
| /// 64-bit number, so it is emulated with the 32-bit version of the instruction. |
| /// |
| /// # Panic |
| /// |
| /// This method will retry calling the instruction a few times, however if all the |
| /// attempts fail, it will `panic`. |
| /// |
| /// In case `panic` occurs, the caller should assume that an non-recoverable |
| /// hardware failure has occured and use another random number genrator instead. |
| </span><span class="attribute">#[inline(always)] |
| </span><span class="kw">fn </span>next_u64(<span class="kw-2">&mut </span><span class="self">self</span>) -> u64 { |
| <span class="kw">match </span><span class="self">self</span>.try_next_u64() { |
| <span class="prelude-val">Ok</span>(result) => result, |
| <span class="prelude-val">Err</span>(c) => busy_loop_fail(c), |
| } |
| } |
| |
| <span class="doccomment">/// Fill a buffer `dest` with random data. |
| /// |
| /// See `try_fill_bytes` for a more extensive documentation. |
| /// |
| /// # Panic |
| /// |
| /// This method will panic any time `try_fill_bytes` would return an error. |
| </span><span class="attribute">#[inline(always)] |
| </span><span class="kw">fn </span>fill_bytes(<span class="kw-2">&mut </span><span class="self">self</span>, dest: <span class="kw-2">&mut </span>[u8]) { |
| <span class="kw">match </span><span class="self">self</span>.try_fill_bytes(dest) { |
| <span class="prelude-val">Ok</span>(result) => result, |
| <span class="prelude-val">Err</span>(c) => busy_loop_fail(c), |
| } |
| } |
| |
| <span class="doccomment">/// Fill a buffer `dest` with random data. |
| /// |
| /// This method will use the most appropriate variant of the instruction available on |
| /// the machine to achieve the greatest single-core throughput, however it has a |
| /// slightly higher setup cost than the plain `next_u32` or `next_u64` methods. |
| /// |
| /// The underlying instruction may fail for variety reasons (such as actual hardware |
| /// failure or exhausted entropy), however the exact reason for the failure is not |
| /// usually exposed. |
| /// |
| /// This method will retry calling the instruction a few times, however if all the |
| /// attempts fail, it will return an error. |
| /// |
| /// If an error is returned, the caller should assume that an non-recoverable hardware |
| /// failure has occured and use another random number genrator instead. |
| </span><span class="attribute">#[inline(always)] |
| </span><span class="kw">fn </span>try_fill_bytes(<span class="kw-2">&mut </span><span class="self">self</span>, dest: <span class="kw-2">&mut </span>[u8]) -> <span class="prelude-ty">Result</span><(), Error> { |
| <span class="self">self</span>.try_fill_bytes(dest).map_err(Into::into) |
| } |
| } |
| }; |
| } |
| |
| <span class="attribute">#[cfg(target_arch = <span class="string">"x86_64"</span>)] |
| </span><span class="macro">impl_rand!</span>( |
| RdRand, |
| <span class="string">"rdrand"</span>, |
| arch::_rdrand16_step, |
| arch::_rdrand32_step, |
| arch::_rdrand64_step, |
| maxstep = arch::_rdrand64_step, |
| maxty = u64 |
| ); |
| <span class="attribute">#[cfg(target_arch = <span class="string">"x86_64"</span>)] |
| </span><span class="macro">impl_rand!</span>( |
| RdSeed, |
| <span class="string">"rdseed"</span>, |
| arch::_rdseed16_step, |
| arch::_rdseed32_step, |
| arch::_rdseed64_step, |
| maxstep = arch::_rdseed64_step, |
| maxty = u64 |
| ); |
| <span class="attribute">#[cfg(target_arch = <span class="string">"x86"</span>)] |
| </span><span class="macro">impl_rand!</span>( |
| RdRand, |
| <span class="string">"rdrand"</span>, |
| arch::_rdrand16_step, |
| arch::_rdrand32_step, |
| arch::_rdrand64_step, |
| maxstep = arch::_rdrand32_step, |
| maxty = u32 |
| ); |
| <span class="attribute">#[cfg(target_arch = <span class="string">"x86"</span>)] |
| </span><span class="macro">impl_rand!</span>( |
| RdSeed, |
| <span class="string">"rdseed"</span>, |
| arch::_rdseed16_step, |
| arch::_rdseed32_step, |
| arch::_rdseed64_step, |
| maxstep = arch::_rdseed32_step, |
| maxty = u32 |
| ); |
| |
| <span class="attribute">#[cfg(test)] |
| </span><span class="kw">mod </span>test { |
| <span class="kw">use super</span>::{RdRand, RdSeed}; |
| <span class="kw">use </span>rand_core::RngCore; |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>rdrand_works() { |
| <span class="kw">let _ </span>= RdRand::new().map(|<span class="kw-2">mut </span>r| { |
| r.next_u32(); |
| r.next_u64(); |
| }); |
| } |
| |
| <span class="attribute">#[repr(C, align(<span class="number">8</span>))] |
| </span><span class="kw">struct </span>FillBuffer([u8; <span class="number">64</span>]); |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>fill_fills_all_bytes() { |
| <span class="kw">let _ </span>= RdRand::new().map(|<span class="kw-2">mut </span>r| { |
| <span class="kw">let </span><span class="kw-2">mut </span>test_buffer; |
| <span class="kw">let </span><span class="kw-2">mut </span>fill_buffer = FillBuffer([<span class="number">0</span>; <span class="number">64</span>]); <span class="comment">// make sure buffer is aligned to 8-bytes... |
| </span><span class="kw">let </span>test_cases = [ |
| (<span class="number">0</span>, <span class="number">64</span>), <span class="comment">// well aligned |
| </span>(<span class="number">8</span>, <span class="number">64</span>), <span class="comment">// well aligned |
| </span>(<span class="number">0</span>, <span class="number">64</span>), <span class="comment">// well aligned |
| </span>(<span class="number">5</span>, <span class="number">64</span>), <span class="comment">// left is non-empty, right is empty. |
| </span>(<span class="number">0</span>, <span class="number">63</span>), <span class="comment">// left is empty, right is non-empty. |
| </span>(<span class="number">5</span>, <span class="number">63</span>), <span class="comment">// left and right both are non-empty. |
| </span>(<span class="number">5</span>, <span class="number">61</span>), <span class="comment">// left and right both are non-empty. |
| </span>(<span class="number">0</span>, <span class="number">8</span>), <span class="comment">// 1 word-worth of data, aligned. |
| </span>(<span class="number">1</span>, <span class="number">9</span>), <span class="comment">// 1 word-worth of data, misaligned. |
| </span>(<span class="number">0</span>, <span class="number">7</span>), <span class="comment">// less than 1 word of data. |
| </span>(<span class="number">1</span>, <span class="number">7</span>), <span class="comment">// less than 1 word of data. |
| </span>]; |
| <span class="lifetime">'outer</span>: <span class="kw">for </span><span class="kw-2">&</span>(start, end) <span class="kw">in </span><span class="kw-2">&</span>test_cases { |
| test_buffer = [<span class="number">0</span>; <span class="number">64</span>]; |
| <span class="kw">for _ in </span><span class="number">0</span>..<span class="number">512 </span>{ |
| fill_buffer.<span class="number">0 </span>= [<span class="number">0</span>; <span class="number">64</span>]; |
| r.fill_bytes(<span class="kw-2">&mut </span>fill_buffer.<span class="number">0</span>[start..end]); |
| <span class="kw">for </span>(b, p) <span class="kw">in </span>test_buffer.iter_mut().zip(fill_buffer.<span class="number">0</span>.iter()) { |
| <span class="kw-2">*</span>b = <span class="kw-2">*</span>b | <span class="kw-2">*</span>p; |
| } |
| <span class="kw">if </span>(<span class="kw-2">&</span>test_buffer[start..end]).iter().all(|x| <span class="kw-2">*</span>x != <span class="number">0</span>) { |
| <span class="macro">assert!</span>( |
| test_buffer[..start].iter().all(|x| <span class="kw-2">*</span>x == <span class="number">0</span>), |
| <span class="string">"all other values must be 0" |
| </span>); |
| <span class="macro">assert!</span>( |
| test_buffer[end..].iter().all(|x| <span class="kw-2">*</span>x == <span class="number">0</span>), |
| <span class="string">"all other values must be 0" |
| </span>); |
| <span class="kw">continue </span><span class="lifetime">'outer</span>; |
| } |
| } |
| <span class="macro">panic!</span>(<span class="string">"wow, we broke it? {} {} {:?}"</span>, start, end, <span class="kw-2">&</span>test_buffer[..]) |
| } |
| }); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>rdseed_works() { |
| <span class="kw">let _ </span>= RdSeed::new().map(|<span class="kw-2">mut </span>r| { |
| r.next_u32(); |
| r.next_u64(); |
| }); |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="rdrand" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |