1
2// Copyright Oliver Kowalke 2009.
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)
6
7#ifndef BOOST_COROUTINES_PROTECTED_STACK_ALLOCATOR_H
8#define BOOST_COROUTINES_PROTECTED_STACK_ALLOCATOR_H
9
10extern "C" {
11#include <fcntl.h>
12#include <sys/mman.h>
13#include <sys/stat.h>
14#include <unistd.h>
15}
16
17#if defined(BOOST_USE_VALGRIND)
18#include <valgrind/valgrind.h>
19#endif
20
21#include <cmath>
22#include <cstddef>
23#include <new>
24
25#include <boost/assert.hpp>
26#include <boost/config.hpp>
27
28#include <boost/coroutine/detail/config.hpp>
29#include <boost/coroutine/stack_context.hpp>
30#include <boost/coroutine/stack_traits.hpp>
31
32#ifdef BOOST_HAS_ABI_HEADERS
33# include BOOST_ABI_PREFIX
34#endif
35
36namespace boost {
37namespace coroutines {
38
39template< typename traitsT >
40struct basic_protected_stack_allocator
41{
42 typedef traitsT traits_type;
43
44 void allocate( stack_context & ctx, std::size_t size = traits_type::minimum_size() )
45 {
46 BOOST_ASSERT( traits_type::minimum_size() <= size);
47 BOOST_ASSERT( traits_type::is_unbounded() || ( traits_type::maximum_size() >= size) );
48
49 // page at bottom will be used as guard-page
50 const std::size_t pages(
51 static_cast< std::size_t >(
52 std::floor(
53 static_cast< float >( size) / traits_type::page_size() ) ) );
54 BOOST_ASSERT_MSG( 2 <= pages, "at least two pages must fit into stack (one page is guard-page)");
55 const std::size_t size_( pages * traits_type::page_size() );
56 BOOST_ASSERT( 0 != size && 0 != size_);
57 BOOST_ASSERT( size_ <= size);
58
59 // conform to POSIX.4 (POSIX.1b-1993, _POSIX_C_SOURCE=199309L)
60#if defined(MAP_ANON)
61 void * limit = ::mmap( addr: 0, len: size_, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, fd: -1, offset: 0);
62#else
63 void * limit = ::mmap( 0, size_, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
64#endif
65 if ( MAP_FAILED == limit) throw std::bad_alloc();
66
67 // conforming to POSIX.1-2001
68#if defined(BOOST_DISABLE_ASSERTS)
69 ::mprotect( limit, traits_type::page_size(), PROT_NONE);
70#else
71 const int result( ::mprotect( addr: limit, len: traits_type::page_size(), PROT_NONE) );
72 BOOST_ASSERT( 0 == result);
73#endif
74
75 ctx.size = size_;
76 ctx.sp = static_cast< char * >( limit) + ctx.size;
77#if defined(BOOST_USE_VALGRIND)
78 ctx.valgrind_stack_id = VALGRIND_STACK_REGISTER( ctx.sp, limit);
79#endif
80 }
81
82 void deallocate( stack_context & ctx)
83 {
84 BOOST_ASSERT( ctx.sp);
85 BOOST_ASSERT( traits_type::minimum_size() <= ctx.size);
86 BOOST_ASSERT( traits_type::is_unbounded() || ( traits_type::maximum_size() >= ctx.size) );
87
88#if defined(BOOST_USE_VALGRIND)
89 VALGRIND_STACK_DEREGISTER( ctx.valgrind_stack_id);
90#endif
91 void * limit = static_cast< char * >( ctx.sp) - ctx.size;
92 // conform to POSIX.4 (POSIX.1b-1993, _POSIX_C_SOURCE=199309L)
93 ::munmap( addr: limit, len: ctx.size);
94 }
95};
96
97typedef basic_protected_stack_allocator< stack_traits > protected_stack_allocator;
98
99}}
100
101#ifdef BOOST_HAS_ABI_HEADERS
102# include BOOST_ABI_SUFFIX
103#endif
104
105#endif // BOOST_COROUTINES_PROTECTED_STACK_ALLOCATOR_H
106

source code of boost/libs/coroutine/include/boost/coroutine/posix/protected_stack_allocator.hpp