| <!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/ctor-0.1.26/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="../../ctor/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="../../ctor/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="attribute">#![recursion_limit = <span class="string">"256"</span>] |
| |
| </span><span class="doccomment">//! Procedural macro for defining global constructor/destructor functions. |
| //! |
| //! This provides module initialization/teardown functions for Rust (like |
| //! `__attribute__((constructor))` in C/C++) for Linux, OSX, and Windows via |
| //! the `#[ctor]` and `#[dtor]` macros. |
| //! |
| //! This library works and is regularly tested on Linux, OSX and Windows, with both `+crt-static` and `-crt-static`. |
| //! Other platforms are supported but not tested as part of the automatic builds. This library will also work as expected in both |
| //! `bin` and `cdylib` outputs, ie: the `ctor` and `dtor` will run at executable or library |
| //! startup/shutdown respectively. |
| //! |
| //! This library currently requires Rust > `1.31.0` at a minimum for the |
| //! procedural macro support. |
| |
| </span><span class="comment">// Code note: |
| |
| // You might wonder why we don't use `__attribute__((destructor))`/etc for |
| // dtor. Unfortunately mingw doesn't appear to properly support section-based |
| // hooks for shutdown, ie: |
| |
| // https://github.com/Alexpux/mingw-w64/blob/d0d7f784833bbb0b2d279310ddc6afb52fe47a46/mingw-w64-crt/crt/crtdll.c |
| |
| // In addition, OSX has removed support for section-based shutdown hooks after |
| // warning about it for a number of years: |
| |
| // https://reviews.llvm.org/D45578 |
| |
| </span><span class="kw">extern crate </span>proc_macro; |
| <span class="kw">extern crate </span>syn; |
| <span class="attribute">#[macro_use] |
| </span><span class="kw">extern crate </span>quote; |
| |
| <span class="kw">use </span>proc_macro::{TokenStream}; |
| |
| <span class="doccomment">/// Attributes required to mark a function as a constructor. This may be exposed in the future if we determine |
| /// it to be stable. |
| </span><span class="attribute">#[doc(hidden)] |
| </span><span class="macro">macro_rules! </span>ctor_attributes { |
| () => { |
| <span class="macro">quote!</span>( |
| <span class="attribute">#[cfg_attr(any(target_os = <span class="string">"linux"</span>, target_os = <span class="string">"android"</span>), link_section = <span class="string">".init_array"</span>)] |
| #[cfg_attr(target_os = <span class="string">"freebsd"</span>, link_section = <span class="string">".init_array"</span>)] |
| #[cfg_attr(target_os = <span class="string">"netbsd"</span>, link_section = <span class="string">".init_array"</span>)] |
| #[cfg_attr(target_os = <span class="string">"openbsd"</span>, link_section = <span class="string">".init_array"</span>)] |
| #[cfg_attr(target_os = <span class="string">"dragonfly"</span>, link_section = <span class="string">".init_array"</span>)] |
| #[cfg_attr(target_os = <span class="string">"illumos"</span>, link_section = <span class="string">".init_array"</span>)] |
| #[cfg_attr(target_os = <span class="string">"haiku"</span>, link_section = <span class="string">".init_array"</span>)] |
| #[cfg_attr(any(target_os = <span class="string">"macos"</span>, target_os = <span class="string">"ios"</span>), link_section = <span class="string">"__DATA,__mod_init_func"</span>)] |
| #[cfg_attr(windows, link_section = <span class="string">".CRT$XCU"</span>)] |
| </span>) |
| }; |
| } |
| |
| <span class="doccomment">/// Marks a function or static variable as a library/executable constructor. |
| /// This uses OS-specific linker sections to call a specific function at |
| /// load time. |
| /// |
| /// Multiple startup functions/statics are supported, but the invocation order is not |
| /// guaranteed. |
| /// |
| /// # Examples |
| /// |
| /// Print a startup message (using `libc_print` for safety): |
| /// |
| /// ```rust |
| /// # extern crate ctor; |
| /// # use ctor::*; |
| /// use libc_print::std_name::println; |
| /// |
| /// #[ctor] |
| /// fn foo() { |
| /// println!("Hello, world!"); |
| /// } |
| /// |
| /// # fn main() { |
| /// println!("main()"); |
| /// # } |
| /// ``` |
| /// |
| /// Make changes to `static` variables: |
| /// |
| /// ```rust |
| /// # extern crate ctor; |
| /// # use ctor::*; |
| /// # use std::sync::atomic::{AtomicBool, Ordering}; |
| /// static INITED: AtomicBool = AtomicBool::new(false); |
| /// |
| /// #[ctor] |
| /// fn foo() { |
| /// INITED.store(true, Ordering::SeqCst); |
| /// } |
| /// ``` |
| /// |
| /// Initialize a `HashMap` at startup time: |
| /// |
| /// ```rust |
| /// # extern crate ctor; |
| /// # use std::collections::HashMap; |
| /// # use ctor::*; |
| /// #[ctor] |
| /// static STATIC_CTOR: HashMap<u32, String> = { |
| /// let mut m = HashMap::new(); |
| /// for i in 0..100 { |
| /// m.insert(i, format!("x*100={}", i*100)); |
| /// } |
| /// m |
| /// }; |
| /// |
| /// # pub fn main() { |
| /// # assert_eq!(STATIC_CTOR.len(), 100); |
| /// # assert_eq!(STATIC_CTOR[&20], "x*100=2000"); |
| /// # } |
| /// ``` |
| /// |
| /// # Details |
| /// |
| /// The `#[ctor]` macro makes use of linker sections to ensure that a |
| /// function is run at startup time. |
| /// |
| /// The above example translates into the following Rust code (approximately): |
| /// |
| ///```rust |
| /// #[used] |
| /// #[cfg_attr(any(target_os = "linux", target_os = "android"), link_section = ".init_array")] |
| /// #[cfg_attr(target_os = "freebsd", link_section = ".init_array")] |
| /// #[cfg_attr(target_os = "netbsd", link_section = ".init_array")] |
| /// #[cfg_attr(target_os = "openbsd", link_section = ".init_array")] |
| /// #[cfg_attr(target_os = "illumos", link_section = ".init_array")] |
| /// #[cfg_attr(any(target_os = "macos", target_os = "ios"), link_section = "__DATA,__mod_init_func")] |
| /// #[cfg_attr(target_os = "windows", link_section = ".CRT$XCU")] |
| /// static FOO: extern fn() = { |
| /// #[cfg_attr(any(target_os = "linux", target_os = "android"), link_section = ".text.startup")] |
| /// extern fn foo() { /* ... */ }; |
| /// foo |
| /// }; |
| /// ``` |
| </span><span class="attribute">#[proc_macro_attribute] |
| </span><span class="kw">pub fn </span>ctor(_attribute: TokenStream, function: TokenStream) -> TokenStream { |
| <span class="kw">let </span>item: syn::Item = <span class="macro">syn::parse_macro_input!</span>(function); |
| <span class="kw">if let </span>syn::Item::Fn(function) = item { |
| validate_item(<span class="string">"ctor"</span>, <span class="kw-2">&</span>function); |
| |
| <span class="kw">let </span>syn::ItemFn { |
| attrs, |
| block, |
| vis, |
| sig: |
| syn::Signature { |
| ident, |
| unsafety, |
| constness, |
| abi, |
| .. |
| }, |
| .. |
| } = function; |
| |
| <span class="comment">// Linux/ELF: https://www.exploit-db.com/papers/13234 |
| |
| // Mac details: https://blog.timac.org/2016/0716-constructor-and-destructor-attributes/ |
| |
| // Why .CRT$XCU on Windows? https://www.cnblogs.com/sunkang/archive/2011/05/24/2055635.html |
| // 'I'=C init, 'C'=C++ init, 'P'=Pre-terminators and 'T'=Terminators |
| |
| </span><span class="kw">let </span>ctor_ident = |
| syn::parse_str::<syn::Ident>(<span class="macro">format!</span>(<span class="string">"{}___rust_ctor___ctor"</span>, ident).as_ref()) |
| .expect(<span class="string">"Unable to create identifier"</span>); |
| |
| <span class="kw">let </span>tokens = <span class="macro">ctor_attributes!</span>(); |
| <span class="kw">let </span>output = <span class="macro">quote!</span>( |
| <span class="attribute">#[cfg(not(any(target_os = <span class="string">"linux"</span>, target_os = <span class="string">"android"</span>, target_os = <span class="string">"freebsd"</span>, target_os = <span class="string">"netbsd"</span>, target_os = <span class="string">"openbsd"</span>, target_os = <span class="string">"dragonfly"</span>, target_os = <span class="string">"illumos"</span>, target_os = <span class="string">"haiku"</span>, target_os = <span class="string">"macos"</span>, target_os = <span class="string">"ios"</span>, windows)))] |
| </span><span class="macro">compile_error!</span>(<span class="string">"#[ctor] is not supported on the current target"</span>); |
| |
| #(#attrs)* |
| #vis #unsafety <span class="kw">extern </span>#abi #constness <span class="kw">fn </span>#ident() #block |
| |
| <span class="attribute">#[used] |
| #[allow(non_upper_case_globals)] |
| #[doc(hidden)] |
| </span>#tokens |
| <span class="kw">static </span>#ctor_ident |
| : |
| <span class="kw">unsafe extern </span><span class="string">"C" </span><span class="kw">fn</span>() = |
| { |
| <span class="attribute">#[cfg_attr(any(target_os = <span class="string">"linux"</span>, target_os = <span class="string">"android"</span>), link_section = <span class="string">".text.startup"</span>)] |
| </span><span class="kw">unsafe extern </span><span class="string">"C" </span><span class="kw">fn </span>#ctor_ident() { #ident() }; |
| #ctor_ident |
| } |
| ; |
| ); |
| |
| <span class="comment">// eprintln!("{}", output); |
| |
| </span>output.into() |
| } <span class="kw">else if let </span>syn::Item::Static(var) = item { |
| <span class="kw">let </span>syn::ItemStatic { |
| ident, |
| mutability, |
| expr, |
| attrs, |
| ty, |
| vis, |
| .. |
| } = var; |
| |
| <span class="kw">if </span>mutability.is_some() { |
| <span class="macro">panic!</span>(<span class="string">"#[ctor]-annotated static objects must not be mutable"</span>); |
| } |
| |
| <span class="kw">if </span>attrs.iter().any(|attr| { |
| attr.path |
| .segments |
| .iter() |
| .any(|segment| segment.ident == <span class="string">"no_mangle"</span>) |
| }) { |
| <span class="macro">panic!</span>(<span class="string">"#[ctor]-annotated static objects do not support #[no_mangle]"</span>); |
| } |
| |
| <span class="kw">let </span>ctor_ident = |
| syn::parse_str::<syn::Ident>(<span class="macro">format!</span>(<span class="string">"{}___rust_ctor___ctor"</span>, ident).as_ref()) |
| .expect(<span class="string">"Unable to create identifier"</span>); |
| <span class="kw">let </span>storage_ident = |
| syn::parse_str::<syn::Ident>(<span class="macro">format!</span>(<span class="string">"{}___rust_ctor___storage"</span>, ident).as_ref()) |
| .expect(<span class="string">"Unable to create identifier"</span>); |
| |
| <span class="kw">let </span>tokens = <span class="macro">ctor_attributes!</span>(); |
| <span class="kw">let </span>output = <span class="macro">quote!</span>( |
| <span class="attribute">#[cfg(not(any(target_os = <span class="string">"linux"</span>, target_os = <span class="string">"android"</span>, target_os = <span class="string">"freebsd"</span>, target_os = <span class="string">"netbsd"</span>, target_os = <span class="string">"openbsd"</span>, target_os = <span class="string">"dragonfly"</span>, target_os = <span class="string">"illumos"</span>, target_os = <span class="string">"haiku"</span>, target_os = <span class="string">"macos"</span>, target_os = <span class="string">"ios"</span>, windows)))] |
| </span><span class="macro">compile_error!</span>(<span class="string">"#[ctor] is not supported on the current target"</span>); |
| |
| <span class="comment">// This is mutable, but only by this macro code! |
| </span><span class="kw">static </span><span class="kw-2">mut </span>#storage_ident: <span class="prelude-ty">Option</span><#ty> = <span class="prelude-val">None</span>; |
| |
| <span class="attribute">#[doc(hidden)] |
| #[allow(non_camel_case_types)] |
| </span>#vis <span class="kw">struct </span>#ident<T> { |
| _data: core::marker::PhantomData<T> |
| } |
| |
| #(#attrs)* |
| #vis <span class="kw">static </span>#ident: #ident<#ty> = #ident { |
| _data: core::marker::PhantomData::<#ty> |
| }; |
| |
| <span class="kw">impl </span>core::ops::Deref <span class="kw">for </span>#ident<#ty> { |
| <span class="kw">type </span>Target = #ty; |
| <span class="kw">fn </span>deref(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span><span class="lifetime">'static </span>#ty { |
| <span class="kw">unsafe </span>{ |
| #storage_ident.as_ref().unwrap() |
| } |
| } |
| } |
| |
| <span class="attribute">#[used] |
| #[allow(non_upper_case_globals)] |
| </span>#tokens |
| <span class="kw">static </span>#ctor_ident |
| : |
| <span class="kw">unsafe extern </span><span class="string">"C" </span><span class="kw">fn</span>() = { |
| <span class="attribute">#[cfg_attr(any(target_os = <span class="string">"linux"</span>, target_os = <span class="string">"android"</span>), link_section = <span class="string">".text.startup"</span>)] |
| </span><span class="kw">unsafe extern </span><span class="string">"C" </span><span class="kw">fn </span>initer() { |
| #storage_ident = <span class="prelude-val">Some</span>(#expr); |
| }; initer } |
| ; |
| ); |
| |
| <span class="comment">// eprintln!("{}", output); |
| |
| </span>output.into() |
| } <span class="kw">else </span>{ |
| <span class="macro">panic!</span>(<span class="string">"#[ctor] items must be functions or static globals"</span>); |
| } |
| } |
| |
| <span class="doccomment">/// Marks a function as a library/executable destructor. This uses OS-specific |
| /// linker sections to call a specific function at termination time. |
| /// |
| /// Multiple shutdown functions are supported, but the invocation order is not |
| /// guaranteed. |
| /// |
| /// `sys_common::at_exit` is usually a better solution for shutdown handling, as |
| /// it allows you to use `stdout` in your handlers. |
| /// |
| /// ```rust |
| /// # extern crate ctor; |
| /// # use ctor::*; |
| /// # fn main() {} |
| /// |
| /// #[dtor] |
| /// fn shutdown() { |
| /// /* ... */ |
| /// } |
| /// ``` |
| </span><span class="attribute">#[proc_macro_attribute] |
| </span><span class="kw">pub fn </span>dtor(_attribute: TokenStream, function: TokenStream) -> TokenStream { |
| <span class="kw">let </span>function: syn::ItemFn = <span class="macro">syn::parse_macro_input!</span>(function); |
| validate_item(<span class="string">"dtor"</span>, <span class="kw-2">&</span>function); |
| |
| <span class="kw">let </span>syn::ItemFn { |
| attrs, |
| block, |
| vis, |
| sig: |
| syn::Signature { |
| ident, |
| unsafety, |
| constness, |
| abi, |
| .. |
| }, |
| .. |
| } = function; |
| |
| <span class="kw">let </span>mod_ident = syn::parse_str::<syn::Ident>(<span class="macro">format!</span>(<span class="string">"{}___rust_dtor___mod"</span>, ident).as_ref()) |
| .expect(<span class="string">"Unable to create identifier"</span>); |
| |
| <span class="kw">let </span>dtor_ident = syn::parse_str::<syn::Ident>(<span class="macro">format!</span>(<span class="string">"{}___rust_dtor___dtor"</span>, ident).as_ref()) |
| .expect(<span class="string">"Unable to create identifier"</span>); |
| |
| <span class="kw">let </span>tokens = <span class="macro">ctor_attributes!</span>(); |
| <span class="kw">let </span>output = <span class="macro">quote!</span>( |
| <span class="attribute">#[cfg(not(any(target_os = <span class="string">"linux"</span>, target_os = <span class="string">"android"</span>, target_os = <span class="string">"freebsd"</span>, target_os = <span class="string">"netbsd"</span>, target_os = <span class="string">"openbsd"</span>, target_os = <span class="string">"dragonfly"</span>, target_os = <span class="string">"illumos"</span>, target_os = <span class="string">"haiku"</span>, target_os = <span class="string">"macos"</span>, target_os = <span class="string">"ios"</span>, windows)))] |
| </span><span class="macro">compile_error!</span>(<span class="string">"#[dtor] is not supported on the current target"</span>); |
| |
| #(#attrs)* |
| #vis #unsafety <span class="kw">extern </span>#abi #constness <span class="kw">fn </span>#ident() #block |
| |
| <span class="kw">mod </span>#mod_ident { |
| <span class="kw">use super</span>::#ident; |
| |
| <span class="comment">// Note that we avoid a dep on the libc crate by linking directly to atexit functions |
| |
| </span><span class="attribute">#[cfg(not(any(target_os = <span class="string">"macos"</span>, target_os = <span class="string">"ios"</span>)))] |
| #[inline(always)] |
| </span><span class="kw">unsafe fn </span>do_atexit(cb: <span class="kw">unsafe extern fn</span>()) { |
| <span class="kw">extern </span><span class="string">"C" </span>{ |
| <span class="kw">fn </span>atexit(cb: <span class="kw">unsafe extern fn</span>()); |
| } |
| atexit(cb); |
| } |
| |
| <span class="comment">// For platforms that have __cxa_atexit, we register the dtor as scoped to dso_handle |
| </span><span class="attribute">#[cfg(any(target_os = <span class="string">"macos"</span>, target_os = <span class="string">"ios"</span>))] |
| #[inline(always)] |
| </span><span class="kw">unsafe fn </span>do_atexit(cb: <span class="kw">unsafe extern fn</span>()) { |
| <span class="kw">extern </span><span class="string">"C" </span>{ |
| <span class="kw">static </span>__dso_handle: <span class="kw-2">*const </span>u8; |
| <span class="kw">fn </span>__cxa_atexit(cb: <span class="kw">unsafe extern fn</span>(), arg: <span class="kw-2">*const </span>u8, dso_handle: <span class="kw-2">*const </span>u8); |
| } |
| __cxa_atexit(cb, std::ptr::null(), __dso_handle); |
| } |
| |
| <span class="attribute">#[used] |
| #[allow(non_upper_case_globals)] |
| </span>#tokens |
| <span class="kw">static </span>__dtor_export |
| : |
| <span class="kw">unsafe extern </span><span class="string">"C" </span><span class="kw">fn</span>() = |
| { |
| <span class="attribute">#[cfg_attr(any(target_os = <span class="string">"linux"</span>, target_os = <span class="string">"android"</span>), link_section = <span class="string">".text.exit"</span>)] |
| </span><span class="kw">unsafe extern </span><span class="string">"C" </span><span class="kw">fn </span>#dtor_ident() { #ident() }; |
| <span class="attribute">#[cfg_attr(any(target_os = <span class="string">"linux"</span>, target_os = <span class="string">"android"</span>), link_section = <span class="string">".text.startup"</span>)] |
| </span><span class="kw">unsafe extern fn </span>__dtor_atexit() { |
| do_atexit(#dtor_ident); |
| }; |
| __dtor_atexit |
| }; |
| } |
| ); |
| |
| <span class="comment">// eprintln!("{}", output); |
| |
| </span>output.into() |
| } |
| |
| <span class="kw">fn </span>validate_item(typ: <span class="kw-2">&</span>str, item: <span class="kw-2">&</span>syn::ItemFn) { |
| <span class="kw">let </span>syn::ItemFn { vis, sig, .. } = item; |
| |
| <span class="comment">// Ensure that visibility modifier is not present |
| </span><span class="kw">match </span>vis { |
| syn::Visibility::Inherited => {} |
| <span class="kw">_ </span>=> <span class="macro">panic!</span>(<span class="string">"#[{}] methods must not have visibility modifiers"</span>, typ), |
| } |
| |
| <span class="comment">// No parameters allowed |
| </span><span class="kw">if </span>!sig.inputs.is_empty() { |
| <span class="macro">panic!</span>(<span class="string">"#[{}] methods may not have parameters"</span>, typ); |
| } |
| |
| <span class="comment">// No return type allowed |
| </span><span class="kw">match </span>sig.output { |
| syn::ReturnType::Default => {} |
| <span class="kw">_ </span>=> <span class="macro">panic!</span>(<span class="string">"#[{}] methods must not have return types"</span>, typ), |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="ctor" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |