context/windows/protected_fixedsize_stack.hpp

0001
0002 //          Copyright Oliver Kowalke 2014.
0003 // Distributed under the Boost Software License, Version 1.0.
0004 //    (See accompanying file LICENSE_1_0.txt or copy at
0005 //          http://www.boost.org/LICENSE_1_0.txt)
0006
0007 #ifndef BOOST_CONTEXT_PROTECTED_FIXEDSIZE_H
0008 #define BOOST_CONTEXT_PROTECTED_FIXEDSIZE_H
0009
0010 extern "C" {
0011 #include <windows.h>
0012 }
0013
0014 #include <cmath>
0015 #include <cstddef>
0016 #include <new>
0017
0018 #include <boost/assert.hpp>
0019 #include <boost/config.hpp>
0020 #include <boost/core/ignore_unused.hpp>
0021
0022 #include <boost/context/detail/config.hpp>
0023 #include <boost/context/stack_context.hpp>
0024 #include <boost/context/stack_traits.hpp>
0025
0026 #ifdef BOOST_HAS_ABI_HEADERS
0027 #  include BOOST_ABI_PREFIX
0028 #endif
0029
0030 namespace boost {
0031 namespace context {
0032
0033 template< typename traitsT >
0034 class basic_protected_fixedsize_stack {
0035 private:
0036     std::size_t     size_;
0037
0038 public:
0039     typedef traitsT traits_type;
0040
0041     basic_protected_fixedsize_stack( std::size_t size = traits_type::default_size() ) BOOST_NOEXCEPT_OR_NOTHROW :
0042         size_( size) {
0043     }
0044
0045     stack_context allocate() {
0046         // calculate how many pages are required
0047         const std::size_t pages = (size_ + traits_type::page_size() - 1) / traits_type::page_size();
0048         // add one page at bottom that will be used as guard-page
0049         const std::size_t size__ = ( pages + 1) * traits_type::page_size();
0050
0051         void * vp = ::VirtualAlloc( 0, size__, MEM_COMMIT, PAGE_READWRITE);
0052         if ( ! vp) throw std::bad_alloc();
0053
0054         DWORD old_options;
0055         const BOOL result = ::VirtualProtect(
0056             vp, traits_type::page_size(), PAGE_READWRITE | PAGE_GUARD /*PAGE_NOACCESS*/, & old_options);
0057         boost::ignore_unused(result);
0058         BOOST_ASSERT( FALSE != result);
0059
0060         stack_context sctx;
0061         sctx.size = size__;
0062         sctx.sp = static_cast< char * >( vp) + sctx.size;
0063         return sctx;
0064     }
0065
0066     void deallocate( stack_context & sctx) BOOST_NOEXCEPT_OR_NOTHROW {
0067         BOOST_ASSERT( sctx.sp);
0068
0069         void * vp = static_cast< char * >( sctx.sp) - sctx.size;
0070         ::VirtualFree( vp, 0, MEM_RELEASE);
0071     }
0072 };
0073
0074 typedef basic_protected_fixedsize_stack< stack_traits > protected_fixedsize_stack;
0075
0076 }}
0077
0078 #ifdef BOOST_HAS_ABI_HEADERS
0079 #  include BOOST_ABI_SUFFIX
0080 #endif
0081
0082 #endif // BOOST_CONTEXT_PROTECTED_FIXEDSIZE_H