2 // Copyright Oliver Kowalke 2014.
3 // Distributed under the Boost Software License, Version 1.0.
4 // (See accompanying file LICENSE_1_0.txt or copy at
5 // http://www.boost.org/LICENSE_1_0.txt)
7 #ifndef BOOST_CONTEXT_PROTECTED_FIXEDSIZE_H
8 #define BOOST_CONTEXT_PROTECTED_FIXEDSIZE_H
21 #include <boost/assert.hpp>
22 #include <boost/config.hpp>
24 #include <boost/context/detail/config.hpp>
25 #include <boost/context/stack_context.hpp>
26 #include <boost/context/stack_traits.hpp>
28 #if defined(BOOST_USE_VALGRIND)
29 #include <valgrind/valgrind.h>
32 #ifdef BOOST_HAS_ABI_HEADERS
33 # include BOOST_ABI_PREFIX
39 template< typename traitsT >
40 class basic_protected_fixedsize_stack {
45 typedef traitsT traits_type;
47 basic_protected_fixedsize_stack( std::size_t size = traits_type::default_size() ) BOOST_NOEXCEPT_OR_NOTHROW :
51 stack_context allocate() {
52 // calculate how many pages are required
53 const std::size_t pages(
54 static_cast< std::size_t >(
56 static_cast< float >( size_) / traits_type::page_size() ) ) );
57 // add one page at bottom that will be used as guard-page
58 const std::size_t size__ = ( pages + 1) * traits_type::page_size();
60 // conform to POSIX.4 (POSIX.1b-1993, _POSIX_C_SOURCE=199309L)
62 void * vp = ::mmap( 0, size__, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
64 void * vp = ::mmap( 0, size__, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
66 if ( MAP_FAILED == vp) throw std::bad_alloc();
68 // conforming to POSIX.1-2001
69 #if defined(BOOST_DISABLE_ASSERTS)
70 ::mprotect( vp, traits_type::page_size(), PROT_NONE);
72 const int result( ::mprotect( vp, traits_type::page_size(), PROT_NONE) );
73 BOOST_ASSERT( 0 == result);
78 sctx.sp = static_cast< char * >( vp) + sctx.size;
79 #if defined(BOOST_USE_VALGRIND)
80 sctx.valgrind_stack_id = VALGRIND_STACK_REGISTER( sctx.sp, vp);
85 void deallocate( stack_context & sctx) BOOST_NOEXCEPT_OR_NOTHROW {
86 BOOST_ASSERT( sctx.sp);
88 #if defined(BOOST_USE_VALGRIND)
89 VALGRIND_STACK_DEREGISTER( sctx.valgrind_stack_id);
92 void * vp = static_cast< char * >( sctx.sp) - sctx.size;
93 // conform to POSIX.4 (POSIX.1b-1993, _POSIX_C_SOURCE=199309L)
94 ::munmap( vp, sctx.size);
98 typedef basic_protected_fixedsize_stack< stack_traits > protected_fixedsize_stack;
102 #ifdef BOOST_HAS_ABI_HEADERS
103 # include BOOST_ABI_SUFFIX
106 #endif // BOOST_CONTEXT_PROTECTED_FIXEDSIZE_H