diff --git a/src/liblibc b/src/liblibc index a64ee24718c02..403bdc8839491 160000 --- a/src/liblibc +++ b/src/liblibc @@ -1 +1 @@ -Subproject commit a64ee24718c0289b82a77d692cf56f8a1226de51 +Subproject commit 403bdc88394919f297bdb365032044cc0481c319 diff --git a/src/libstd/sys/unix/stack_overflow.rs b/src/libstd/sys/unix/stack_overflow.rs index a868abbb7312a..1b5faf64ad6e5 100644 --- a/src/libstd/sys/unix/stack_overflow.rs +++ b/src/libstd/sys/unix/stack_overflow.rs @@ -46,7 +46,7 @@ mod imp { use super::Handler; use mem; use ptr; - use libc::{sigaltstack, SIGSTKSZ}; + use libc::{sigaltstack, SIGSTKSZ, SS_DISABLE}; use libc::{sigaction, SIGBUS, SIG_DFL, SA_SIGINFO, SA_ONSTACK, sighandler_t}; use libc; @@ -169,13 +169,32 @@ mod imp { } pub unsafe fn make_handler() -> Handler { - let stack = get_stack(); - sigaltstack(&stack, ptr::null_mut()); - Handler { _data: stack.ss_sp as *mut libc::c_void } + let mut stack = mem::zeroed(); + sigaltstack(ptr::null(), &mut stack); + // Configure alternate signal stack, if one is not already set. + if stack.ss_flags & SS_DISABLE != 0 { + stack = get_stack(); + sigaltstack(&stack, ptr::null_mut()); + Handler { _data: stack.ss_sp as *mut libc::c_void } + } else { + Handler { _data: ptr::null_mut() } + } } pub unsafe fn drop_handler(handler: &mut Handler) { - munmap(handler._data, SIGSTKSZ); + if !handler._data.is_null() { + let stack = libc::stack_t { + ss_sp: ptr::null_mut(), + ss_flags: SS_DISABLE, + // Workaround for bug in MacOS implementation of sigaltstack + // UNIX2003 which returns ENOMEM when disabling a stack while + // passing ss_size smaller than MINSIGSTKSZ. According to POSIX + // both ss_sp and ss_size should be ignored in this case. + ss_size: SIGSTKSZ, + }; + sigaltstack(&stack, ptr::null_mut()); + munmap(handler._data, SIGSTKSZ); + } } } diff --git a/src/test/run-pass/signal-alternate-stack-cleanup.rs b/src/test/run-pass/signal-alternate-stack-cleanup.rs new file mode 100644 index 0000000000000..26fa36f0c13d4 --- /dev/null +++ b/src/test/run-pass/signal-alternate-stack-cleanup.rs @@ -0,0 +1,44 @@ +// Copyright 2016 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +// Previously memory for alternate signal stack have been unmapped during +// main thread exit while still being in use by signal handlers. This test +// triggers this situation by sending signal from atexit handler. +// +// ignore-windows + +#![feature(libc)] +extern crate libc; + +use libc::*; + +unsafe extern fn signal_handler(signum: c_int, _: *mut siginfo_t, _: *mut c_void) { + assert_eq!(signum, SIGWINCH); +} + +extern fn send_signal() { + unsafe { + raise(SIGWINCH); + } +} + +fn main() { + unsafe { + // Install signal hander that runs on alternate signal stack. + let mut action: sigaction = std::mem::zeroed(); + action.sa_flags = SA_SIGINFO | SA_ONSTACK; + action.sa_sigaction = signal_handler as sighandler_t; + sigaction(SIGWINCH, &action, std::ptr::null_mut()); + + // Send SIGWINCH on exit. + atexit(send_signal); + } +} +