coroutine/posix/protected_stack_allocator.hpp

0001
0002 //          Copyright Oliver Kowalke 2009.
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_COROUTINES_PROTECTED_STACK_ALLOCATOR_H
0008 #define BOOST_COROUTINES_PROTECTED_STACK_ALLOCATOR_H
0009
0010 extern "C" {
0011 #include <fcntl.h>
0012 #include <sys/mman.h>
0013 #include <sys/stat.h>
0014 #include <unistd.h>
0015 }
0016
0017 #if defined(BOOST_USE_VALGRIND)
0018 #include <valgrind/valgrind.h>
0019 #endif
0020
0021 #include <cmath>
0022 #include <cstddef>
0023 #include <new>
0024
0025 #include <boost/assert.hpp>
0026 #include <boost/config.hpp>
0027
0028 #include <boost/coroutine/detail/config.hpp>
0029 #include <boost/coroutine/stack_context.hpp>
0030 #include <boost/coroutine/stack_traits.hpp>
0031
0032 #ifdef BOOST_HAS_ABI_HEADERS
0033 #  include BOOST_ABI_PREFIX
0034 #endif
0035
0036 namespace boost {
0037 namespace coroutines {
0038
0039 template< typename traitsT >
0040 struct basic_protected_stack_allocator
0041 {
0042     typedef traitsT traits_type;
0043
0044     void allocate( stack_context & ctx, std::size_t size = traits_type::minimum_size() )
0045     {
0046         BOOST_ASSERT( traits_type::minimum_size() <= size);
0047         BOOST_ASSERT( traits_type::is_unbounded() || ( traits_type::maximum_size() >= size) );
0048
0049         // page at bottom will be used as guard-page
0050         const std::size_t pages(
0051             static_cast< std::size_t >(
0052                 std::floor(
0053                     static_cast< float >( size) / traits_type::page_size() ) ) );
0054         BOOST_ASSERT_MSG( 2 <= pages, "at least two pages must fit into stack (one page is guard-page)");
0055         const std::size_t size_( pages * traits_type::page_size() );
0056         BOOST_ASSERT( 0 != size && 0 != size_);
0057         BOOST_ASSERT( size_ <= size);
0058
0059         // conform to POSIX.4 (POSIX.1b-1993, _POSIX_C_SOURCE=199309L)
0060 #if defined(MAP_ANON)
0061         void * limit = ::mmap( 0, size_, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
0062 #else
0063         void * limit = ::mmap( 0, size_, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
0064 #endif
0065         if ( MAP_FAILED == limit) throw std::bad_alloc();
0066
0067         // conforming to POSIX.1-2001
0068 #if defined(BOOST_DISABLE_ASSERTS)
0069         ::mprotect( limit, traits_type::page_size(), PROT_NONE);
0070 #else
0071         const int result( ::mprotect( limit, traits_type::page_size(), PROT_NONE) );
0072         BOOST_ASSERT( 0 == result);
0073 #endif
0074
0075         ctx.size = size_;
0076         ctx.sp = static_cast< char * >( limit) + ctx.size;
0077 #if defined(BOOST_USE_VALGRIND)
0078         ctx.valgrind_stack_id = VALGRIND_STACK_REGISTER( ctx.sp, limit);
0079 #endif
0080     }
0081
0082     void deallocate( stack_context & ctx)
0083     {
0084         BOOST_ASSERT( ctx.sp);
0085         BOOST_ASSERT( traits_type::minimum_size() <= ctx.size);
0086         BOOST_ASSERT( traits_type::is_unbounded() || ( traits_type::maximum_size() >= ctx.size) );
0087
0088 #if defined(BOOST_USE_VALGRIND)
0089         VALGRIND_STACK_DEREGISTER( ctx.valgrind_stack_id);
0090 #endif
0091         void * limit = static_cast< char * >( ctx.sp) - ctx.size;
0092         // conform to POSIX.4 (POSIX.1b-1993, _POSIX_C_SOURCE=199309L)
0093         ::munmap( limit, ctx.size);
0094     }
0095 };
0096
0097 typedef basic_protected_stack_allocator< stack_traits > protected_stack_allocator;
0098
0099 }}
0100
0101 #ifdef BOOST_HAS_ABI_HEADERS
0102 #  include BOOST_ABI_SUFFIX
0103 #endif
0104
0105 #endif // BOOST_COROUTINES_PROTECTED_STACK_ALLOCATOR_H