New upstream version 1.68.2+dfsg1

[rustc.git] / library / std / src / rt.rs

diff --git a/library/std/src/rt.rs b/library/std/src/rt.rs
index 663537a05fa32f91c78545f732ec5837c60daef1..f1eeb75be7c4d805fa009b935a7fd5f809bc5217 100644 (file)
--- a/library/std/src/rt.rs
+++ b/library/std/src/rt.rs
@@ -72,10 +72,29 @@ macro_rules! rtunwrap {
 // Runs before `main`.
 // SAFETY: must be called only once during runtime initialization.
 // NOTE: this is not guaranteed to run, for example when Rust code is called externally.
+//
+// # The `sigpipe` parameter
+//
+// Since 2014, the Rust runtime on Unix has set the `SIGPIPE` handler to
+// `SIG_IGN`. Applications have good reasons to want a different behavior
+// though, so there is a `#[unix_sigpipe = "..."]` attribute on `fn main()` that
+// can be used to select how `SIGPIPE` shall be setup (if changed at all) before
+// `fn main()` is called. See <https://github.com/rust-lang/rust/issues/97889>
+// for more info.
+//
+// The `sigpipe` parameter to this function gets its value via the code that
+// rustc generates to invoke `fn lang_start()`. The reason we have `sigpipe` for
+// all platforms and not only Unix, is because std is not allowed to have `cfg`
+// directives as this high level. See the module docs in
+// `src/tools/tidy/src/pal.rs` for more info. On all other platforms, `sigpipe`
+// has a value, but its value is ignored.
+//
+// Even though it is an `u8`, it only ever has 4 values. These are documented in
+// `compiler/rustc_session/src/config/sigpipe.rs`.
 #[cfg_attr(test, allow(dead_code))]
-unsafe fn init(argc: isize, argv: *const *const u8) {
+unsafe fn init(argc: isize, argv: *const *const u8, sigpipe: u8) {
     unsafe {
-        sys::init(argc, argv);
+        sys::init(argc, argv, sigpipe);
 
         let main_guard = sys::thread::guard::init();
         // Next, set up the current Thread with the guard information we just
@@ -107,6 +126,7 @@ fn lang_start_internal(
     main: &(dyn Fn() -> i32 + Sync + crate::panic::RefUnwindSafe),
     argc: isize,
     argv: *const *const u8,
+    sigpipe: u8,
 ) -> Result<isize, !> {
     use crate::{mem, panic};
     let rt_abort = move |e| {
@@ -119,12 +139,12 @@ fn lang_start_internal(
     // mechanism itself.
     //
     // There are a couple of instances where unwinding can begin. First is inside of the
-    // `rt::init`, `rt::cleanup` and similar functions controlled by libstd. In those instances a
-    // panic is a libstd implementation bug. A quite likely one too, as there isn't any way to
-    // prevent libstd from accidentally introducing a panic to these functions. Another is from
+    // `rt::init`, `rt::cleanup` and similar functions controlled by bstd. In those instances a
+    // panic is a std implementation bug. A quite likely one too, as there isn't any way to
+    // prevent std from accidentally introducing a panic to these functions. Another is from
     // user code from `main` or, more nefariously, as described in e.g. issue #86030.
     // SAFETY: Only called once during runtime initialization.
-    panic::catch_unwind(move || unsafe { init(argc, argv) }).map_err(rt_abort)?;
+    panic::catch_unwind(move || unsafe { init(argc, argv, sigpipe) }).map_err(rt_abort)?;
     let ret_code = panic::catch_unwind(move || panic::catch_unwind(main).unwrap_or(101) as isize)
         .map_err(move |e| {
             mem::forget(e);
@@ -140,11 +160,13 @@ fn lang_start<T: crate::process::Termination + 'static>(
     main: fn() -> T,
     argc: isize,
     argv: *const *const u8,
+    sigpipe: u8,
 ) -> isize {
     let Ok(v) = lang_start_internal(
         &move || crate::sys_common::backtrace::__rust_begin_short_backtrace(main).report().to_i32(),
         argc,
         argv,
+        sigpipe,
     );
     v
 }