| <!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/nix-0.26.2/src/sys/memfd.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>memfd.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="../../../nix/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="../../../nix/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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| </pre><pre class="rust"><code><span class="doccomment">//! Interfaces for managing memory-backed files. |
| |
| </span><span class="kw">use </span>cfg_if::cfg_if; |
| <span class="kw">use </span>std::os::unix::io::RawFd; |
| |
| <span class="kw">use </span><span class="kw">crate</span>::errno::Errno; |
| <span class="kw">use </span><span class="kw">crate</span>::Result; |
| <span class="kw">use </span>std::ffi::CStr; |
| |
| <span class="macro">libc_bitflags!</span>( |
| <span class="doccomment">/// Options that change the behavior of [`memfd_create`]. |
| </span><span class="kw">pub struct </span>MemFdCreateFlag: libc::c_uint { |
| <span class="doccomment">/// Set the close-on-exec ([`FD_CLOEXEC`]) flag on the new file descriptor. |
| /// |
| /// By default, the new file descriptor is set to remain open across an [`execve`] |
| /// (the `FD_CLOEXEC` flag is initially disabled). This flag can be used to change |
| /// this default. The file offset is set to the beginning of the file (see [`lseek`]). |
| /// |
| /// See also the description of the `O_CLOEXEC` flag in [`open(2)`]. |
| /// |
| /// [`execve`]: crate::unistd::execve |
| /// [`lseek`]: crate::unistd::lseek |
| /// [`FD_CLOEXEC`]: crate::fcntl::FdFlag::FD_CLOEXEC |
| /// [`open(2)`]: https://man7.org/linux/man-pages/man2/open.2.html |
| </span>MFD_CLOEXEC; |
| <span class="doccomment">/// Allow sealing operations on this file. |
| /// |
| /// See also the file sealing notes given in [`memfd_create(2)`]. |
| /// |
| /// [`memfd_create(2)`]: https://man7.org/linux/man-pages/man2/memfd_create.2.html |
| </span>MFD_ALLOW_SEALING; |
| } |
| ); |
| |
| <span class="doccomment">/// Creates an anonymous file that lives in memory, and return a file-descriptor to it. |
| /// |
| /// The file behaves like a regular file, and so can be modified, truncated, memory-mapped, and so on. |
| /// However, unlike a regular file, it lives in RAM and has a volatile backing storage. |
| /// |
| /// For more information, see [`memfd_create(2)`]. |
| /// |
| /// [`memfd_create(2)`]: https://man7.org/linux/man-pages/man2/memfd_create.2.html |
| </span><span class="kw">pub fn </span>memfd_create(name: <span class="kw-2">&</span>CStr, flags: MemFdCreateFlag) -> <span class="prelude-ty">Result</span><RawFd> { |
| <span class="kw">let </span>res = <span class="kw">unsafe </span>{ |
| <span class="macro">cfg_if! </span>{ |
| <span class="kw">if </span><span class="attribute">#[cfg(all( |
| <span class="comment">// Android does not have a memfd_create symbol |
| </span>not(target_os = <span class="string">"android"</span>), |
| any( |
| target_os = <span class="string">"freebsd"</span>, |
| <span class="comment">// If the OS is Linux, gnu and musl expose a memfd_create symbol but not uclibc |
| </span>target_env = <span class="string">"gnu"</span>, |
| target_env = <span class="string">"musl"</span>, |
| )))] |
| </span>{ |
| libc::memfd_create(name.as_ptr(), flags.bits()) |
| } <span class="kw">else </span>{ |
| libc::syscall(libc::SYS_memfd_create, name.as_ptr(), flags.bits()) |
| } |
| } |
| }; |
| |
| Errno::result(res).map(|r| r <span class="kw">as </span>RawFd) |
| } |
| </code></pre></div> |
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