hphp/test/slow/signal/change_handler_after_fork.php

   1 <?hh
   2
   3 // parent and child processes share the same handler here
   4 function handler($signo) {
   5
   6   if ($signo == SIGUSR2) {
   7     if (SignalChangeHandlerAfterForkPhp::$child == 0) {
   8       echo "child: I received SIGUSR2...\n";
   9       echo "child: sending SIGUSR1 to inform parent\n";
  10       posix_kill(SignalChangeHandlerAfterForkPhp::$parent, SIGUSR1);
  11       exit;
  12     } else {
  13       echo "parent: I received SIGUSR2, switching to new handler\n";
  14       pcntl_signal(SIGUSR1, newhandler<>);
  15       pcntl_signal(SIGUSR2, newhandler<>);
  16       echo "parent: sending SIGUSR2 to child as ack\n";
  17       posix_kill(SignalChangeHandlerAfterForkPhp::$child, SIGUSR2);
  18     }
  19   } else if ($signo == SIGUSR1) {
  20     if (SignalChangeHandlerAfterForkPhp::$child != 0) {
  21       echo "parent: received SIGUSR1 from child\n";
  22       $status = null;
  23       pcntl_waitpid(SignalChangeHandlerAfterForkPhp::$child, inout $status);
  24       echo "child exit with code $status";
  25       exit(0);
  26     }
  27   }
  28 }
  29
  30 function newhandler($signo) {
  31
  32   echo "parent: new handler invoked\n";
  33   $status = null;
  34   pcntl_waitpid(SignalChangeHandlerAfterForkPhp::$child, inout $status);
  35   exit(0);
  36 }
  37
  38 function waitForSignal($nsec) {
  39   for ($i = 0; $i < $nsec; ++$i) {
  40     sleep(1);
  41   }
  42 }
  43
  44 function main() {
  45   pcntl_signal(SIGUSR1, handler<>);
  46   pcntl_signal(SIGUSR2, handler<>);
  47
  48   SignalChangeHandlerAfterForkPhp::$child = pcntl_fork();  // 0 in the child process
  49
  50   // FIXME(T80291213): fix race condition in dbgo mode
  51   sleep(1);
  52
  53   if (SignalChangeHandlerAfterForkPhp::$child == 0) {
  54     echo "do some work in child process\n";
  55     posix_kill(SignalChangeHandlerAfterForkPhp::$parent, SIGUSR2);
  56     waitForSignal(10);
  57   } else {
  58     waitForSignal(10);
  59   }
  60
  61   echo "this shouldn't be printed.";
  62 }
  63
  64 abstract final class SignalChangeHandlerAfterForkPhp {
  65   public static $parent;
  66   public static $child;
  67 }
  68 <<__EntryPoint>>
  69 function entrypoint_change_handler_after_fork(): void {
  70
  71   SignalChangeHandlerAfterForkPhp::$parent = posix_getpid();
  72   SignalChangeHandlerAfterForkPhp::$child = 0;
  73
  74   main();
  75 }