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// Copyright Oliver Kowalke 2009.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
#ifndef BOOST_COROUTINES_PROTECTED_STACK_ALLOCATOR_H
#define BOOST_COROUTINES_PROTECTED_STACK_ALLOCATOR_H
extern "C" {
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
}
#if defined(BOOST_USE_VALGRIND)
#include <valgrind/valgrind.h>
#endif
#include <cmath>
#include <cstddef>
#include <new>
#include <boost/assert.hpp>
#include <boost/config.hpp>
#include <boost/coroutine/detail/config.hpp>
#include <boost/coroutine/stack_context.hpp>
#include <boost/coroutine/stack_traits.hpp>
#ifdef BOOST_HAS_ABI_HEADERS
# include BOOST_ABI_PREFIX
#endif
namespace boost {
namespace coroutines {
template< typename traitsT >
struct basic_protected_stack_allocator
{
typedef traitsT traits_type;
void allocate( stack_context & ctx, std::size_t size = traits_type::minimum_size() )
{
BOOST_ASSERT( traits_type::minimum_size() <= size);
BOOST_ASSERT( traits_type::is_unbounded() || ( traits_type::maximum_size() >= size) );
// page at bottom will be used as guard-page
const std::size_t pages(
static_cast< std::size_t >(
std::floor(
static_cast< float >( size) / traits_type::page_size() ) ) );
BOOST_ASSERT_MSG( 2 <= pages, "at least two pages must fit into stack (one page is guard-page)");
const std::size_t size_( pages * traits_type::page_size() );
BOOST_ASSERT( 0 != size && 0 != size_);
BOOST_ASSERT( size_ <= size);
// conform to POSIX.4 (POSIX.1b-1993, _POSIX_C_SOURCE=199309L)
#if defined(MAP_ANON)
void * limit = ::mmap( 0, size_, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
#else
void * limit = ::mmap( 0, size_, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
#endif
if ( MAP_FAILED == limit) throw std::bad_alloc();
// conforming to POSIX.1-2001
#if defined(BOOST_DISABLE_ASSERTS)
::mprotect( limit, traits_type::page_size(), PROT_NONE);
#else
const int result( ::mprotect( limit, traits_type::page_size(), PROT_NONE) );
BOOST_ASSERT( 0 == result);
#endif
ctx.size = size_;
ctx.sp = static_cast< char * >( limit) + ctx.size;
#if defined(BOOST_USE_VALGRIND)
ctx.valgrind_stack_id = VALGRIND_STACK_REGISTER( ctx.sp, limit);
#endif
}
void deallocate( stack_context & ctx)
{
BOOST_ASSERT( ctx.sp);
BOOST_ASSERT( traits_type::minimum_size() <= ctx.size);
BOOST_ASSERT( traits_type::is_unbounded() || ( traits_type::maximum_size() >= ctx.size) );
#if defined(BOOST_USE_VALGRIND)
VALGRIND_STACK_DEREGISTER( ctx.valgrind_stack_id);
#endif
void * limit = static_cast< char * >( ctx.sp) - ctx.size;
// conform to POSIX.4 (POSIX.1b-1993, _POSIX_C_SOURCE=199309L)
::munmap( limit, ctx.size);
}
};
typedef basic_protected_stack_allocator< stack_traits > protected_stack_allocator;
}}
#ifdef BOOST_HAS_ABI_HEADERS
# include BOOST_ABI_SUFFIX
#endif
#endif // BOOST_COROUTINES_PROTECTED_STACK_ALLOCATOR_H
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