<!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 to the Rust file `libstd/sys/unix/pipe.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>pipe.rs.html -- source</title><link rel="stylesheet" type="text/css" href="../../../../normalize.css"><link rel="stylesheet" type="text/css" href="../../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../../../../dark.css"><link rel="stylesheet" type="text/css" href="../../../../light.css" id="themeStyle"><script src="../../../../storage.js"></script><link rel="shortcut icon" href="https://doc.rust-lang.org/favicon.ico"></head><body class="rustdoc source"><!--[if lte IE 8]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="sidebar-menu">☰</div><a href='../../../../std/index.html'><img src='https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png' alt='logo' width='100'></a></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!"><img src="../../../../brush.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices"></div></div><script src="../../../../theme.js"></script><nav class="sub"><form class="search-form js-only"><div class="search-container"><input class="search-input" name="search" autocomplete="off" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><a id="settings-menu" href="../../../../settings.html"><img src="../../../../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><pre class="line-numbers"><span id="1"> 1</span> <span id="2"> 2</span> <span id="3"> 3</span> <span id="4"> 4</span> <span id="5"> 5</span> <span id="6"> 6</span> <span id="7"> 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id="126">126</span> <span id="127">127</span> <span id="128">128</span> <span id="129">129</span> <span id="130">130</span> </pre><pre class="rust "> <span class="comment">// Copyright 2015 The Rust Project Developers. See the COPYRIGHT</span> <span class="comment">// file at the top-level directory of this distribution and at</span> <span class="comment">// http://rust-lang.org/COPYRIGHT.</span> <span class="comment">//</span> <span class="comment">// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or</span> <span class="comment">// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license</span> <span class="comment">// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your</span> <span class="comment">// option. This file may not be copied, modified, or distributed</span> <span class="comment">// except according to those terms.</span> <span class="kw">use</span> <span class="ident">io</span>; <span class="kw">use</span> <span class="ident">libc</span>::{<span class="self">self</span>, <span class="ident">c_int</span>}; <span class="kw">use</span> <span class="ident">mem</span>; <span class="kw">use</span> <span class="ident">sync</span>::<span class="ident">atomic</span>::{<span class="ident">AtomicBool</span>, <span class="ident">ATOMIC_BOOL_INIT</span>, <span class="ident">Ordering</span>}; <span class="kw">use</span> <span class="ident">sys</span>::<span class="ident">fd</span>::<span class="ident">FileDesc</span>; <span class="kw">use</span> <span class="ident">sys</span>::{<span class="ident">cvt</span>, <span class="ident">cvt_r</span>}; <span class="comment">////////////////////////////////////////////////////////////////////////////////</span> <span class="comment">// Anonymous pipes</span> <span class="comment">////////////////////////////////////////////////////////////////////////////////</span> <span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">AnonPipe</span>(<span class="ident">FileDesc</span>); <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">anon_pipe</span>() <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span>(<span class="ident">AnonPipe</span>, <span class="ident">AnonPipe</span>)<span class="op">></span> { <span class="macro">weak</span><span class="macro">!</span> { <span class="kw">fn</span> <span class="ident">pipe2</span>(<span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">c_int</span>, <span class="ident">c_int</span>) <span class="op">-></span> <span class="ident">c_int</span> } <span class="kw">static</span> <span class="ident">INVALID</span>: <span class="ident">AtomicBool</span> <span class="op">=</span> <span class="ident">ATOMIC_BOOL_INIT</span>; <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">fds</span> <span class="op">=</span> [<span class="number">0</span>; <span class="number">2</span>]; <span class="comment">// Unfortunately the only known way right now to create atomically set the</span> <span class="comment">// CLOEXEC flag is to use the `pipe2` syscall on Linux. This was added in</span> <span class="comment">// 2.6.27, however, and because we support 2.6.18 we must detect this</span> <span class="comment">// support dynamically.</span> <span class="kw">if</span> <span class="macro">cfg</span><span class="macro">!</span>(<span class="ident">any</span>(<span class="ident">target_os</span> <span class="op">=</span> <span class="string">"dragonfly"</span>, <span class="ident">target_os</span> <span class="op">=</span> <span class="string">"freebsd"</span>, <span class="ident">target_os</span> <span class="op">=</span> <span class="string">"linux"</span>, <span class="ident">target_os</span> <span class="op">=</span> <span class="string">"netbsd"</span>, <span class="ident">target_os</span> <span class="op">=</span> <span class="string">"openbsd"</span>)) <span class="op">&&</span> <span class="op">!</span><span class="ident">INVALID</span>.<span class="ident">load</span>(<span class="ident">Ordering</span>::<span class="ident">SeqCst</span>) { <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">pipe</span>) <span class="op">=</span> <span class="ident">pipe2</span>.<span class="ident">get</span>() { <span class="comment">// Note that despite calling a glibc function here we may still</span> <span class="comment">// get ENOSYS. Glibc has `pipe2` since 2.9 and doesn't try to</span> <span class="comment">// emulate on older kernels, so if you happen to be running on</span> <span class="comment">// an older kernel you may see `pipe2` as a symbol but still not</span> <span class="comment">// see the syscall.</span> <span class="kw">match</span> <span class="ident">cvt</span>(<span class="kw">unsafe</span> { <span class="ident">pipe</span>(<span class="ident">fds</span>.<span class="ident">as_mut_ptr</span>(), <span class="ident">libc</span>::<span class="ident">O_CLOEXEC</span>) }) { <span class="prelude-val">Ok</span>(<span class="kw">_</span>) <span class="op">=></span> { <span class="kw">return</span> <span class="prelude-val">Ok</span>((<span class="ident">AnonPipe</span>(<span class="ident">FileDesc</span>::<span class="ident">new</span>(<span class="ident">fds</span>[<span class="number">0</span>])), <span class="ident">AnonPipe</span>(<span class="ident">FileDesc</span>::<span class="ident">new</span>(<span class="ident">fds</span>[<span class="number">1</span>])))); } <span class="prelude-val">Err</span>(<span class="kw-2">ref</span> <span class="ident">e</span>) <span class="kw">if</span> <span class="ident">e</span>.<span class="ident">raw_os_error</span>() <span class="op">==</span> <span class="prelude-val">Some</span>(<span class="ident">libc</span>::<span class="ident">ENOSYS</span>) <span class="op">=></span> { <span class="ident">INVALID</span>.<span class="ident">store</span>(<span class="bool-val">true</span>, <span class="ident">Ordering</span>::<span class="ident">SeqCst</span>); } <span class="prelude-val">Err</span>(<span class="ident">e</span>) <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident">e</span>), } } } <span class="ident">cvt</span>(<span class="kw">unsafe</span> { <span class="ident">libc</span>::<span class="ident">pipe</span>(<span class="ident">fds</span>.<span class="ident">as_mut_ptr</span>()) })<span class="question-mark">?</span>; <span class="kw">let</span> <span class="ident">fd0</span> <span class="op">=</span> <span class="ident">FileDesc</span>::<span class="ident">new</span>(<span class="ident">fds</span>[<span class="number">0</span>]); <span class="kw">let</span> <span class="ident">fd1</span> <span class="op">=</span> <span class="ident">FileDesc</span>::<span class="ident">new</span>(<span class="ident">fds</span>[<span class="number">1</span>]); <span class="ident">fd0</span>.<span class="ident">set_cloexec</span>()<span class="question-mark">?</span>; <span class="ident">fd1</span>.<span class="ident">set_cloexec</span>()<span class="question-mark">?</span>; <span class="prelude-val">Ok</span>((<span class="ident">AnonPipe</span>(<span class="ident">fd0</span>), <span class="ident">AnonPipe</span>(<span class="ident">fd1</span>))) } <span class="kw">impl</span> <span class="ident">AnonPipe</span> { <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">read</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">buf</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> [<span class="ident">u8</span>]) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span> { <span class="self">self</span>.<span class="number">0</span>.<span class="ident">read</span>(<span class="ident">buf</span>) } <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">write</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">buf</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>]) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span> { <span class="self">self</span>.<span class="number">0</span>.<span class="ident">write</span>(<span class="ident">buf</span>) } <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">fd</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="kw-2">&</span><span class="ident">FileDesc</span> { <span class="kw-2">&</span><span class="self">self</span>.<span class="number">0</span> } <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">into_fd</span>(<span class="self">self</span>) <span class="op">-></span> <span class="ident">FileDesc</span> { <span class="self">self</span>.<span class="number">0</span> } } <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">read2</span>(<span class="ident">p1</span>: <span class="ident">AnonPipe</span>, <span class="ident">v1</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">Vec</span><span class="op"><</span><span class="ident">u8</span><span class="op">></span>, <span class="ident">p2</span>: <span class="ident">AnonPipe</span>, <span class="ident">v2</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">Vec</span><span class="op"><</span><span class="ident">u8</span><span class="op">></span>) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span>()<span class="op">></span> { <span class="comment">// Set both pipes into nonblocking mode as we're gonna be reading from both</span> <span class="comment">// in the `select` loop below, and we wouldn't want one to block the other!</span> <span class="kw">let</span> <span class="ident">p1</span> <span class="op">=</span> <span class="ident">p1</span>.<span class="ident">into_fd</span>(); <span class="kw">let</span> <span class="ident">p2</span> <span class="op">=</span> <span class="ident">p2</span>.<span class="ident">into_fd</span>(); <span class="ident">p1</span>.<span class="ident">set_nonblocking</span>(<span class="bool-val">true</span>)<span class="question-mark">?</span>; <span class="ident">p2</span>.<span class="ident">set_nonblocking</span>(<span class="bool-val">true</span>)<span class="question-mark">?</span>; <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">fds</span>: [<span class="ident">libc</span>::<span class="ident">pollfd</span>; <span class="number">2</span>] <span class="op">=</span> <span class="kw">unsafe</span> { <span class="ident">mem</span>::<span class="ident">zeroed</span>() }; <span class="ident">fds</span>[<span class="number">0</span>].<span class="ident">fd</span> <span class="op">=</span> <span class="ident">p1</span>.<span class="ident">raw</span>(); <span class="ident">fds</span>[<span class="number">0</span>].<span class="ident">events</span> <span class="op">=</span> <span class="ident">libc</span>::<span class="ident">POLLIN</span>; <span class="ident">fds</span>[<span class="number">1</span>].<span class="ident">fd</span> <span class="op">=</span> <span class="ident">p2</span>.<span class="ident">raw</span>(); <span class="ident">fds</span>[<span class="number">1</span>].<span class="ident">events</span> <span class="op">=</span> <span class="ident">libc</span>::<span class="ident">POLLIN</span>; <span class="kw">loop</span> { <span class="comment">// wait for either pipe to become readable using `poll`</span> <span class="ident">cvt_r</span>(<span class="op">||</span> <span class="kw">unsafe</span> { <span class="ident">libc</span>::<span class="ident">poll</span>(<span class="ident">fds</span>.<span class="ident">as_mut_ptr</span>(), <span class="number">2</span>, <span class="op">-</span><span class="number">1</span>) })<span class="question-mark">?</span>; <span class="comment">// Read as much as we can from each pipe, ignoring EWOULDBLOCK or</span> <span class="comment">// EAGAIN. If we hit EOF, then this will happen because the underlying</span> <span class="comment">// reader will return Ok(0), in which case we'll see `Ok` ourselves. In</span> <span class="comment">// this case we flip the other fd back into blocking mode and read</span> <span class="comment">// whatever's leftover on that file descriptor.</span> <span class="kw">let</span> <span class="ident">read</span> <span class="op">=</span> <span class="op">|</span><span class="ident">fd</span>: <span class="kw-2">&</span><span class="ident">FileDesc</span>, <span class="ident">dst</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">Vec</span><span class="op"><</span><span class="ident">u8</span><span class="op">></span><span class="op">|</span> { <span class="kw">match</span> <span class="ident">fd</span>.<span class="ident">read_to_end</span>(<span class="ident">dst</span>) { <span class="prelude-val">Ok</span>(<span class="kw">_</span>) <span class="op">=></span> <span class="prelude-val">Ok</span>(<span class="bool-val">true</span>), <span class="prelude-val">Err</span>(<span class="ident">e</span>) <span class="op">=></span> { <span class="kw">if</span> <span class="ident">e</span>.<span class="ident">raw_os_error</span>() <span class="op">==</span> <span class="prelude-val">Some</span>(<span class="ident">libc</span>::<span class="ident">EWOULDBLOCK</span>) <span class="op">||</span> <span class="ident">e</span>.<span class="ident">raw_os_error</span>() <span class="op">==</span> <span class="prelude-val">Some</span>(<span class="ident">libc</span>::<span class="ident">EAGAIN</span>) { <span class="prelude-val">Ok</span>(<span class="bool-val">false</span>) } <span class="kw">else</span> { <span class="prelude-val">Err</span>(<span class="ident">e</span>) } } } }; <span class="kw">if</span> <span class="ident">fds</span>[<span class="number">0</span>].<span class="ident">revents</span> <span class="op">!=</span> <span class="number">0</span> <span class="op">&&</span> <span class="ident">read</span>(<span class="kw-2">&</span><span class="ident">p1</span>, <span class="ident">v1</span>)<span class="question-mark">?</span> { <span class="ident">p2</span>.<span class="ident">set_nonblocking</span>(<span class="bool-val">false</span>)<span class="question-mark">?</span>; <span class="kw">return</span> <span class="ident">p2</span>.<span class="ident">read_to_end</span>(<span class="ident">v2</span>).<span class="ident">map</span>(<span class="op">|</span><span class="kw">_</span><span class="op">|</span> ()); } <span class="kw">if</span> <span class="ident">fds</span>[<span class="number">1</span>].<span class="ident">revents</span> <span class="op">!=</span> <span class="number">0</span> <span class="op">&&</span> <span class="ident">read</span>(<span class="kw-2">&</span><span class="ident">p2</span>, <span class="ident">v2</span>)<span class="question-mark">?</span> { <span class="ident">p1</span>.<span class="ident">set_nonblocking</span>(<span class="bool-val">false</span>)<span class="question-mark">?</span>; <span class="kw">return</span> <span class="ident">p1</span>.<span class="ident">read_to_end</span>(<span class="ident">v1</span>).<span class="ident">map</span>(<span class="op">|</span><span class="kw">_</span><span class="op">|</span> ()); } } } </pre> </section><section id="search" class="content hidden"></section><section class="footer"></section><aside id="help" class="hidden"><div><h1 class="hidden">Help</h1><div class="shortcuts"><h2>Keyboard Shortcuts</h2><dl><dt><kbd>?</kbd></dt><dd>Show this help dialog</dd><dt><kbd>S</kbd></dt><dd>Focus the search field</dd><dt><kbd>↑</kbd></dt><dd>Move up in search results</dd><dt><kbd>↓</kbd></dt><dd>Move down in search results</dd><dt><kbd>↹</kbd></dt><dd>Switch tab</dd><dt><kbd>⏎</kbd></dt><dd>Go to active search result</dd><dt><kbd>+</kbd></dt><dd>Expand all sections</dd><dt><kbd>-</kbd></dt><dd>Collapse all sections</dd></dl></div><div class="infos"><h2>Search Tricks</h2><p>Prefix searches with a type followed by a colon (e.g. <code>fn:</code>) to restrict the search to a given type.</p><p>Accepted types are: <code>fn</code>, <code>mod</code>, <code>struct</code>, <code>enum</code>, <code>trait</code>, <code>type</code>, <code>macro</code>, and <code>const</code>.</p><p>Search functions by type signature (e.g. <code>vec -> usize</code> or <code>* -> vec</code>)</p><p>Search multiple things at once by splitting your query with comma (e.g. <code>str,u8</code> or <code>String,struct:Vec,test</code>)</p></div></div></aside><script>window.rootPath = "../../../../";window.currentCrate = "std";</script><script src="../../../../aliases.js"></script><script src="../../../../main.js"></script><script defer src="../../../../search-index.js"></script></body></html>