hphp/hack/src/utils/parent/parentimpl.cpp

   1 #include <thread>
   2 #include <mutex>
   3 #include <cassert>
   4 #include <atomic>
   5
   6 #include <unistd.h>
   7
   8 #include "parentimpl.h"
   9
  10
  11 std::mutex watchdog_mut;
  12 static int watchdog_count = 0;
  13
  14
  15 static void check_and_die(int interval, int grace) noexcept {
  16   assert(interval > 0);
  17   assert(grace > 0);
  18   for (;;) {
  19     // when we get reparented
  20     // exit immediately
  21     if (getppid() == 1) {
  22       sleep(static_cast<unsigned>(grace));
  23       exit(20);
  24     }
  25     sleep(static_cast<unsigned>(interval));
  26   }
  27 }
  28
  29
  30 extern "C" void exit_on_parent_exit_(int interval, int grace) noexcept {
  31   assert(interval > 0);
  32   assert(grace > 0);
  33   std::lock_guard<std::mutex> guard(watchdog_mut);
  34   assert(watchdog_count == 0 || watchdog_count == 1);
  35   if (watchdog_count == 0) {
  36     ++watchdog_count;
  37     std::thread t(check_and_die, interval, grace);
  38     t.detach();
  39   }
  40   return;
  41 }
  42
  43 extern "C" int get_watchdog_count_() noexcept {
  44   std::lock_guard<std::mutex> guard(watchdog_mut);
  45   return watchdog_count;
  46 }