73 lines
2.4 KiB
Rust
73 lines
2.4 KiB
Rust
// This file is part of libfringe, a low-level green threading library.
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// Copyright (c) edef <edef@edef.eu>
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// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or
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// http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
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// http://opensource.org/licenses/MIT>, at your option. This file may not be
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// copied, modified, or distributed except according to those terms.
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extern crate std;
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extern crate libc;
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use self::std::sync::atomic::{ATOMIC_USIZE_INIT, AtomicUsize, Ordering};
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use self::std::ptr;
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use self::std::io::Error as IoError;
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use self::libc::{c_void, c_int, size_t};
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use self::libc::{mmap, mprotect, munmap};
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use self::libc::MAP_FAILED;
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const GUARD_PROT: c_int = libc::PROT_NONE;
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const STACK_PROT: c_int = libc::PROT_READ
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| libc::PROT_WRITE;
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#[cfg(not(any(target_os = "freebsd", target_os = "dragonfly", target_vendor = "apple")))]
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const STACK_FLAGS: c_int = libc::MAP_STACK
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| libc::MAP_PRIVATE
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| libc::MAP_ANON;
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// workaround for http://lists.freebsd.org/pipermail/freebsd-bugs/2011-July/044840.html
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// according to libgreen, DragonFlyBSD suffers from this too
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#[cfg(any(target_os = "freebsd", target_os = "dragonfly", target_vendor = "apple"))]
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const STACK_FLAGS: c_int = libc::MAP_PRIVATE
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| libc::MAP_ANON;
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pub unsafe fn map_stack(len: usize) -> Result<*mut u8, IoError> {
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let ptr = mmap(ptr::null_mut(), len as size_t, STACK_PROT, STACK_FLAGS, -1, 0);
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if ptr == MAP_FAILED {
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Err(IoError::last_os_error())
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} else {
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Ok(ptr as *mut u8)
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}
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}
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pub unsafe fn protect_stack(ptr: *mut u8) -> Result<(), IoError> {
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if mprotect(ptr as *mut c_void, page_size() as size_t, GUARD_PROT) == 0 {
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Ok(())
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} else {
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Err(IoError::last_os_error())
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}
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}
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pub unsafe fn unmap_stack(ptr: *mut u8, len: usize) -> Result<(), IoError> {
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if munmap(ptr as *mut c_void, len as size_t) == 0 {
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Ok(())
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} else {
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Err(IoError::last_os_error())
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}
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}
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pub fn page_size() -> usize {
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#[cold]
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pub fn sys_page_size() -> usize {
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unsafe {
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libc::sysconf(libc::_SC_PAGESIZE) as usize
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}
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}
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static PAGE_SIZE_CACHE: AtomicUsize = ATOMIC_USIZE_INIT;
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match PAGE_SIZE_CACHE.load(Ordering::Relaxed) {
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0 => {
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let page_size = sys_page_size();
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PAGE_SIZE_CACHE.store(page_size, Ordering::Relaxed);
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page_size
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}
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page_size => page_size
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}
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}
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