Function TEST

3rdparty/libprocess/src/tests/reap_tests.cpp:46–101

This test checks that we can reap a non-child process, in terms of receiving the termination notification.

// This test checks that we can reap a non-child process, in terms
// of receiving the termination notification.
TEST(ReapTest, NonChildProcess)
{
  // The child process creates a grandchild and then exits. The
  // grandchild sleeps for 10 seconds. The process tree looks like:
  //  -+- child exit 0
  //   \-+- grandchild sleep 10

  // After the child exits, the grandchild is going to be re-parented
  // by 'init', like this:
  //  -+- child (exit 0)
  //  -+- grandchild sleep 10
  Try<ProcessTree> tree = Fork(None(),
                               Fork(Exec(SLEEP_COMMAND(10))),
                               Exec("exit 0"))();
  ASSERT_SOME(tree);
  ASSERT_EQ(1u, tree->children.size());
  pid_t grandchild = tree->children.front();

  // Reap the grandchild process.
  Future<Option<int>> status = process::reap(grandchild);

  EXPECT_TRUE(status.isPending());

  // Now kill the grandchild.
  // NOTE: We send a SIGKILL here because sometimes the grandchild
  // process seems to be in a hung state and not responding to
  // SIGTERM/SIGINT.
  EXPECT_EQ(0, kill(grandchild, SIGKILL));

  Clock::pause();

  // Now advance time until the Reaper reaps the grandchild.
  while (status.isPending()) {
    Clock::advance(MAX_REAP_INTERVAL());
    Clock::settle();
  }

  AWAIT_READY(status);

  // The status is None because pid is not an immediate child.
  ASSERT_NONE(status.get()) << status->get();

  // Reap the child as well to clean up after ourselves.
  status = process::reap(tree->process.pid);

  // Now advance time until the child is reaped.
  while (status.isPending()) {
    Clock::advance(MAX_REAP_INTERVAL());
    Clock::settle();
  }

  // Check if the status is correct.
  AWAIT_EXPECT_WEXITSTATUS_EQ(0, status);

  Clock::resume();
}