boost/asio/detail/posix_signal_blocker.hpp

   1 //
   2 // posix_signal_blocker.hpp
   3 // ~~~~~~~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2008 Christopher M. Kohlhoff (chris at kohlhoff dot com)
   6 //
   7 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   9 //
  10
  11 #ifndef BOOST_ASIO_DETAIL_POSIX_SIGNAL_BLOCKER_HPP
  12 #define BOOST_ASIO_DETAIL_POSIX_SIGNAL_BLOCKER_HPP
  13
  14 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  15 # pragma once
  16 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  17
  18 #include <boost/asio/detail/push_options.hpp>
  19
  20 #include <boost/asio/detail/push_options.hpp>
  21 #include <boost/config.hpp>
  22 #include <boost/asio/detail/pop_options.hpp>
  23
  24 #if defined(BOOST_HAS_PTHREADS)
  25
  26 #include <boost/asio/detail/push_options.hpp>
  27 #include <csignal>
  28 #include <pthread.h>
  29 #include <signal.h>
  30 #include <boost/asio/detail/pop_options.hpp>
  31
  32 #include <boost/asio/detail/noncopyable.hpp>
  33
  34 namespace boost {
  35 namespace asio {
  36 namespace detail {
  37
  38 class posix_signal_blocker
  39   : private noncopyable
  40 {
  41 public:
  42   // Constructor blocks all signals for the calling thread.
  43   posix_signal_blocker()
  44     : blocked_(false)
  45   {
  46     sigset_t new_mask;
  47     sigfillset(&new_mask);
  48     blocked_ = (pthread_sigmask(SIG_BLOCK, &new_mask, &old_mask_) == 0);
  49   }
  50
  51   // Destructor restores the previous signal mask.
  52   ~posix_signal_blocker()
  53   {
  54     if (blocked_)
  55       pthread_sigmask(SIG_SETMASK, &old_mask_, 0);
  56   }
  57
  58   // Block all signals for the calling thread.
  59   void block()
  60   {
  61     if (!blocked_)
  62     {
  63       sigset_t new_mask;
  64       sigfillset(&new_mask);
  65       blocked_ = (pthread_sigmask(SIG_BLOCK, &new_mask, &old_mask_) == 0);
  66     }
  67   }
  68
  69   // Restore the previous signal mask.
  70   void unblock()
  71   {
  72     if (blocked_)
  73       blocked_ = (pthread_sigmask(SIG_SETMASK, &old_mask_, 0) != 0);
  74   }
  75
  76 private:
  77   // Have signals been blocked.
  78   bool blocked_;
  79
  80   // The previous signal mask.
  81   sigset_t old_mask_;
  82 };
  83
  84 } // namespace detail
  85 } // namespace asio
  86 } // namespace boost
  87
  88 #endif // defined(BOOST_HAS_PTHREADS)
  89
  90 #include <boost/asio/detail/pop_options.hpp>
  91
  92 #endif // BOOST_ASIO_DETAIL_POSIX_SIGNAL_BLOCKER_HPP