ceph/src/boost/libs/context/include/boost/context/posix/protected_fixedsize_stack.hpp

   1
   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