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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) | |
6 | ||
7 | #ifndef BOOST_CONTEXT_PROTECTED_FIXEDSIZE_H | |
8 | #define BOOST_CONTEXT_PROTECTED_FIXEDSIZE_H | |
9 | ||
10 | extern "C" { | |
11 | #include <fcntl.h> | |
12 | #include <sys/mman.h> | |
13 | #include <sys/stat.h> | |
14 | #include <unistd.h> | |
15 | } | |
16 | ||
17 | #include <cmath> | |
18 | #include <cstddef> | |
19 | #include <new> | |
20 | ||
21 | #include <boost/assert.hpp> | |
22 | #include <boost/config.hpp> | |
23 | ||
24 | #include <boost/context/detail/config.hpp> | |
25 | #include <boost/context/stack_context.hpp> | |
26 | #include <boost/context/stack_traits.hpp> | |
27 | ||
28 | #if defined(BOOST_USE_VALGRIND) | |
29 | #include <valgrind/valgrind.h> | |
30 | #endif | |
31 | ||
32 | #ifdef BOOST_HAS_ABI_HEADERS | |
33 | # include BOOST_ABI_PREFIX | |
34 | #endif | |
35 | ||
36 | namespace boost { | |
37 | namespace context { | |
38 | ||
39 | template< typename traitsT > | |
40 | class basic_protected_fixedsize_stack { | |
41 | private: | |
42 | std::size_t size_; | |
43 | ||
44 | public: | |
45 | typedef traitsT traits_type; | |
46 | ||
47 | basic_protected_fixedsize_stack( std::size_t size = traits_type::default_size() ) BOOST_NOEXCEPT_OR_NOTHROW : | |
48 | size_( size) { | |
49 | BOOST_ASSERT( traits_type::minimum_size() <= size_); | |
50 | BOOST_ASSERT( traits_type::is_unbounded() || ( traits_type::maximum_size() >= size_) ); | |
51 | } | |
52 | ||
53 | stack_context allocate() { | |
54 | // page at bottom will be used as guard-page | |
55 | const std::size_t pages( | |
56 | static_cast< std::size_t >( | |
57 | std::floor( | |
58 | static_cast< float >( size_) / traits_type::page_size() ) ) ); | |
59 | BOOST_ASSERT_MSG( 2 <= pages, "at least two pages must fit into stack (one page is guard-page)"); | |
60 | const std::size_t size__( pages * traits_type::page_size() ); | |
61 | BOOST_ASSERT( 0 != size_ && 0 != size__); | |
62 | BOOST_ASSERT( size__ <= size_); | |
63 | ||
64 | // conform to POSIX.4 (POSIX.1b-1993, _POSIX_C_SOURCE=199309L) | |
65 | #if defined(MAP_ANON) | |
66 | void * vp = ::mmap( 0, size__, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0); | |
67 | #else | |
68 | void * vp = ::mmap( 0, size__, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); | |
69 | #endif | |
70 | if ( MAP_FAILED == vp) throw std::bad_alloc(); | |
71 | ||
72 | // conforming to POSIX.1-2001 | |
73 | #if defined(BOOST_DISABLE_ASSERTS) | |
74 | ::mprotect( vp, traits_type::page_size(), PROT_NONE); | |
75 | #else | |
76 | const int result( ::mprotect( vp, traits_type::page_size(), PROT_NONE) ); | |
77 | BOOST_ASSERT( 0 == result); | |
78 | #endif | |
79 | ||
80 | stack_context sctx; | |
81 | sctx.size = size__; | |
82 | sctx.sp = static_cast< char * >( vp) + sctx.size; | |
83 | #if defined(BOOST_USE_VALGRIND) | |
84 | sctx.valgrind_stack_id = VALGRIND_STACK_REGISTER( sctx.sp, vp); | |
85 | #endif | |
86 | return sctx; | |
87 | } | |
88 | ||
89 | void deallocate( stack_context & sctx) BOOST_NOEXCEPT_OR_NOTHROW { | |
90 | BOOST_ASSERT( sctx.sp); | |
91 | BOOST_ASSERT( traits_type::minimum_size() <= sctx.size); | |
92 | BOOST_ASSERT( traits_type::is_unbounded() || ( traits_type::maximum_size() >= sctx.size) ); | |
93 | ||
94 | #if defined(BOOST_USE_VALGRIND) | |
95 | VALGRIND_STACK_DEREGISTER( sctx.valgrind_stack_id); | |
96 | #endif | |
97 | ||
98 | void * vp = static_cast< char * >( sctx.sp) - sctx.size; | |
99 | // conform to POSIX.4 (POSIX.1b-1993, _POSIX_C_SOURCE=199309L) | |
100 | ::munmap( vp, sctx.size); | |
101 | } | |
102 | }; | |
103 | ||
104 | typedef basic_protected_fixedsize_stack< stack_traits > protected_fixedsize_stack; | |
105 | ||
106 | }} | |
107 | ||
108 | #ifdef BOOST_HAS_ABI_HEADERS | |
109 | # include BOOST_ABI_SUFFIX | |
110 | #endif | |
111 | ||
112 | #endif // BOOST_CONTEXT_PROTECTED_FIXEDSIZE_H |