ceph/src/boost/boost/process/detail/posix/is_running.hpp

   1 // Copyright (c) 2016 Klemens D. Morgenstern
   2 //
   3 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   4 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   5
   6 #ifndef BOOST_PROCESS_DETAIL_POSIX_IS_RUNNING_HPP
   7 #define BOOST_PROCESS_DETAIL_POSIX_IS_RUNNING_HPP
   8
   9 #include <boost/process/detail/config.hpp>
  10 #include <boost/process/detail/posix/child_handle.hpp>
  11 #include <system_error>
  12 #include <sys/wait.h>
  13
  14 namespace boost { namespace process { namespace detail { namespace posix {
  15
  16 // Use the "stopped" state (WIFSTOPPED) to indicate "not terminated".
  17 // This bit arrangement of status codes is not guaranteed by POSIX, but (according to comments in
  18 // the glibc <bits/waitstatus.h> header) is the same across systems in practice.
  19 constexpr int still_active = 0x017f;
  20 static_assert(WIFSTOPPED(still_active), "Expected still_active to indicate WIFSTOPPED");
  21 static_assert(!WIFEXITED(still_active), "Expected still_active to not indicate WIFEXITED");
  22 static_assert(!WIFSIGNALED(still_active), "Expected still_active to not indicate WIFSIGNALED");
  23 static_assert(!WIFCONTINUED(still_active), "Expected still_active to not indicate WIFCONTINUED");
  24
  25 inline bool is_running(int code)
  26 {
  27     return !WIFEXITED(code) && !WIFSIGNALED(code);
  28 }
  29
  30 inline bool is_running(const child_handle &p, int & exit_code, std::error_code &ec) noexcept
  31 {
  32     int status;
  33     auto ret = ::waitpid(p.pid, &status, WNOHANG);
  34
  35     if (ret == -1)
  36     {
  37         if (errno != ECHILD) //because it no child is running, than this one isn't either, obviously.
  38             ec = ::boost::process::detail::get_last_error();
  39         return false;
  40     }
  41     else if (ret == 0)
  42         return true;
  43     else
  44     {
  45         ec.clear();
  46
  47         if (!is_running(status))
  48             exit_code = status;
  49
  50         return false;
  51     }
  52 }
  53
  54 inline bool is_running(const child_handle &p, int & exit_code)
  55 {
  56     std::error_code ec;
  57     bool b = is_running(p, exit_code, ec);
  58     boost::process::detail::throw_error(ec, "waitpid(2) failed in is_running");
  59     return b;
  60 }
  61
  62 inline int eval_exit_status(int code)
  63 {
  64     if (WIFEXITED(code))
  65     {
  66         return WEXITSTATUS(code);
  67     }
  68     else if (WIFSIGNALED(code))
  69     {
  70         return WTERMSIG(code);
  71     }
  72     else
  73     {
  74         return code;
  75     }
  76 }
  77
  78 }}}}
  79
  80 #endif