/*** This file is part of systemd. Copyright 2014 David Herrmann <dh.herrmann@gmail.com> systemd is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. systemd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with systemd; If not, see <http://www.gnu.org/licenses/>. ***/ /* * IPC barrier tests * These tests verify the correct behavior of the IPC Barrier implementation. * Note that the tests use alarm-timers to verify dead-locks and timeouts. These * might not work on slow machines where 20ms are too short to perform specific * operations (though, very unlikely). In case that turns out true, we have to * increase it at the slightly cost of lengthen test-duration on other machines. */ #include <stdio.h> #include <sys/time.h> #include <sys/wait.h> #include <unistd.h> #include "barrier.h" #include "util.h" /* 20ms to test deadlocks; All timings use multiples of this constant as * alarm/sleep timers. If this timeout is too small for slow machines to perform * the requested operations, we have to increase it. On an i7 this works fine * with 1ms base-time, so 20ms should be just fine for everyone. */ #define BASE_TIME (20 * USEC_PER_MSEC) static void set_alarm(usec_t usecs) { struct itimerval v = { }; timeval_store(&v.it_value, usecs); assert_se(setitimer(ITIMER_REAL, &v, NULL) >= 0); } static void sleep_for(usec_t usecs) { /* stupid usleep() might fail if >1000000 */ assert_se(usecs < USEC_PER_SEC); usleep(usecs); } #define TEST_BARRIER(_FUNCTION, _CHILD_CODE, _WAIT_CHILD, _PARENT_CODE, _WAIT_PARENT) \ static void _FUNCTION(void) { \ Barrier b = BARRIER_NULL; \ pid_t pid1, pid2; \ \ assert_se(barrier_create(&b) >= 0); \ assert_se(b.me > 0); \ assert_se(b.them > 0); \ assert_se(b.pipe[0] > 0); \ assert_se(b.pipe[1] > 0); \ \ pid1 = fork(); \ assert_se(pid1 >= 0); \ if (pid1 == 0) { \ barrier_set_role(&b, BARRIER_CHILD); \ { _CHILD_CODE; } \ exit(42); \ } \ \ pid2 = fork(); \ assert_se(pid2 >= 0); \ if (pid2 == 0) { \ barrier_set_role(&b, BARRIER_PARENT); \ { _PARENT_CODE; } \ exit(42); \ } \ \ barrier_destroy(&b); \ set_alarm(999999); \ { _WAIT_CHILD; } \ { _WAIT_PARENT; } \ set_alarm(0); \ } #define TEST_BARRIER_WAIT_SUCCESS(_pid) \ ({ \ int pidr, status; \ pidr = waitpid(_pid, &status, 0); \ assert_se(pidr == _pid); \ assert_se(WIFEXITED(status)); \ assert_se(WEXITSTATUS(status) == 42); \ }) #define TEST_BARRIER_WAIT_ALARM(_pid) \ ({ \ int pidr, status; \ pidr = waitpid(_pid, &status, 0); \ assert_se(pidr == _pid); \ assert_se(WIFSIGNALED(status)); \ assert_se(WTERMSIG(status) == SIGALRM); \ }) /* * Test basic sync points * This places a barrier in both processes and waits synchronously for them. * The timeout makes sure the sync works as expected. The sleep_for() on one side * makes sure the exit of the parent does not overwrite previous barriers. Due * to the sleep_for(), we know that the parent already exited, thus there's a * pending HUP on the pipe. However, the barrier_sync() prefers reads on the * eventfd, thus we can safely wait on the barrier. */ TEST_BARRIER(test_barrier_sync, ({ set_alarm(BASE_TIME * 10); assert_se(barrier_place(&b)); sleep_for(BASE_TIME * 2); assert_se(barrier_sync(&b)); }), TEST_BARRIER_WAIT_SUCCESS(pid1), ({ set_alarm(BASE_TIME * 10); assert_se(barrier_place(&b)); assert_se(barrier_sync(&b)); }), TEST_BARRIER_WAIT_SUCCESS(pid2)); /* * Test wait_next() * This places a barrier in the parent and syncs on it. The child sleeps while * the parent places the barrier and then waits for a barrier. The wait will * succeed as the child hasn't read the parent's barrier, yet. The following * barrier and sync synchronize the exit. */ TEST_BARRIER(test_barrier_wait_next, ({ sleep_for(BASE_TIME); set_alarm(BASE_TIME * 10); assert_se(barrier_wait_next(&b)); assert_se(barrier_place(&b)); assert_se(barrier_sync(&b)); }), TEST_BARRIER_WAIT_SUCCESS(pid1), ({ set_alarm(BASE_TIME * 4); assert_se(barrier_place(&b)); assert_se(barrier_sync(&b)); }), TEST_BARRIER_WAIT_SUCCESS(pid2)); /* * Test wait_next() multiple times * This places two barriers in the parent and waits for the child to exit. The * child sleeps 20ms so both barriers _should_ be in place. It then waits for * the parent to place the next barrier twice. The first call will fetch both * barriers and return. However, the second call will stall as the parent does * not place a 3rd barrier (the sleep caught two barriers). wait_next() is does * not look at barrier-links so this stall is expected. Thus this test times * out. */ TEST_BARRIER(test_barrier_wait_next_twice, ({ sleep_for(BASE_TIME); set_alarm(BASE_TIME); assert_se(barrier_wait_next(&b)); assert_se(barrier_wait_next(&b)); assert_se(0); }), TEST_BARRIER_WAIT_ALARM(pid1), ({ set_alarm(BASE_TIME * 10); assert_se(barrier_place(&b)); assert_se(barrier_place(&b)); sleep_for(BASE_TIME * 4); }), TEST_BARRIER_WAIT_SUCCESS(pid2)); /* * Test wait_next() with local barriers * This is the same as test_barrier_wait_next_twice, but places local barriers * between both waits. This does not have any effect on the wait so it times out * like the other test. */ TEST_BARRIER(test_barrier_wait_next_twice_local, ({ sleep_for(BASE_TIME); set_alarm(BASE_TIME); assert_se(barrier_wait_next(&b)); assert_se(barrier_place(&b)); assert_se(barrier_place(&b)); assert_se(barrier_wait_next(&b)); assert_se(0); }), TEST_BARRIER_WAIT_ALARM(pid1), ({ set_alarm(BASE_TIME * 10); assert_se(barrier_place(&b)); assert_se(barrier_place(&b)); sleep_for(BASE_TIME * 4); }), TEST_BARRIER_WAIT_SUCCESS(pid2)); /* * Test wait_next() with sync_next() * This is again the same as test_barrier_wait_next_twice but uses a * synced wait as the second wait. This works just fine because the local state * has no barriers placed, therefore, the remote is always in sync. */ TEST_BARRIER(test_barrier_wait_next_twice_sync, ({ sleep_for(BASE_TIME); set_alarm(BASE_TIME); assert_se(barrier_wait_next(&b)); assert_se(barrier_sync_next(&b)); }), TEST_BARRIER_WAIT_SUCCESS(pid1), ({ set_alarm(BASE_TIME * 10); assert_se(barrier_place(&b)); assert_se(barrier_place(&b)); }), TEST_BARRIER_WAIT_SUCCESS(pid2)); /* * Test wait_next() with sync_next() and local barriers * This is again the same as test_barrier_wait_next_twice_local but uses a * synced wait as the second wait. This works just fine because the local state * is in sync with the remote. */ TEST_BARRIER(test_barrier_wait_next_twice_local_sync, ({ sleep_for(BASE_TIME); set_alarm(BASE_TIME); assert_se(barrier_wait_next(&b)); assert_se(barrier_place(&b)); assert_se(barrier_place(&b)); assert_se(barrier_sync_next(&b)); }), TEST_BARRIER_WAIT_SUCCESS(pid1), ({ set_alarm(BASE_TIME * 10); assert_se(barrier_place(&b)); assert_se(barrier_place(&b)); }), TEST_BARRIER_WAIT_SUCCESS(pid2)); /* * Test sync_next() and sync() * This tests sync_*() synchronizations and makes sure they work fine if the * local state is behind the remote state. */ TEST_BARRIER(test_barrier_sync_next, ({ set_alarm(BASE_TIME * 10); assert_se(barrier_sync_next(&b)); assert_se(barrier_sync(&b)); assert_se(barrier_place(&b)); assert_se(barrier_place(&b)); assert_se(barrier_sync_next(&b)); assert_se(barrier_sync_next(&b)); assert_se(barrier_sync(&b)); }), TEST_BARRIER_WAIT_SUCCESS(pid1), ({ set_alarm(BASE_TIME * 10); sleep_for(BASE_TIME); assert_se(barrier_place(&b)); assert_se(barrier_place(&b)); assert_se(barrier_sync(&b)); }), TEST_BARRIER_WAIT_SUCCESS(pid2)); /* * Test sync_next() and sync() with local barriers * This tests timeouts if sync_*() is used if local barriers are placed but the * remote didn't place any. */ TEST_BARRIER(test_barrier_sync_next_local, ({ set_alarm(BASE_TIME); assert_se(barrier_place(&b)); assert_se(barrier_sync_next(&b)); assert_se(0); }), TEST_BARRIER_WAIT_ALARM(pid1), ({ sleep_for(BASE_TIME * 2); }), TEST_BARRIER_WAIT_SUCCESS(pid2)); /* * Test sync_next() and sync() with local barriers and abortion * This is the same as test_barrier_sync_next_local but aborts the sync in the * parent. Therefore, the sync_next() succeeds just fine due to the abortion. */ TEST_BARRIER(test_barrier_sync_next_local_abort, ({ set_alarm(BASE_TIME * 10); assert_se(barrier_place(&b)); assert_se(!barrier_sync_next(&b)); }), TEST_BARRIER_WAIT_SUCCESS(pid1), ({ assert_se(barrier_abort(&b)); }), TEST_BARRIER_WAIT_SUCCESS(pid2)); /* * Test matched wait_abortion() * This runs wait_abortion() with remote abortion. */ TEST_BARRIER(test_barrier_wait_abortion, ({ set_alarm(BASE_TIME * 10); assert_se(barrier_wait_abortion(&b)); }), TEST_BARRIER_WAIT_SUCCESS(pid1), ({ assert_se(barrier_abort(&b)); }), TEST_BARRIER_WAIT_SUCCESS(pid2)); /* * Test unmatched wait_abortion() * This runs wait_abortion() without any remote abortion going on. It thus must * timeout. */ TEST_BARRIER(test_barrier_wait_abortion_unmatched, ({ set_alarm(BASE_TIME); assert_se(barrier_wait_abortion(&b)); assert_se(0); }), TEST_BARRIER_WAIT_ALARM(pid1), ({ sleep_for(BASE_TIME * 2); }), TEST_BARRIER_WAIT_SUCCESS(pid2)); /* * Test matched wait_abortion() with local abortion * This runs wait_abortion() with local and remote abortion. */ TEST_BARRIER(test_barrier_wait_abortion_local, ({ set_alarm(BASE_TIME * 10); assert_se(barrier_abort(&b)); assert_se(!barrier_wait_abortion(&b)); }), TEST_BARRIER_WAIT_SUCCESS(pid1), ({ assert_se(barrier_abort(&b)); }), TEST_BARRIER_WAIT_SUCCESS(pid2)); /* * Test unmatched wait_abortion() with local abortion * This runs wait_abortion() with only local abortion. This must time out. */ TEST_BARRIER(test_barrier_wait_abortion_local_unmatched, ({ set_alarm(BASE_TIME); assert_se(barrier_abort(&b)); assert_se(!barrier_wait_abortion(&b)); assert_se(0); }), TEST_BARRIER_WAIT_ALARM(pid1), ({ sleep_for(BASE_TIME * 2); }), TEST_BARRIER_WAIT_SUCCESS(pid2)); /* * Test child exit * Place barrier and sync with the child. The child only exits()s, which should * cause an implicit abortion and wake the parent. */ TEST_BARRIER(test_barrier_exit, ({ }), TEST_BARRIER_WAIT_SUCCESS(pid1), ({ set_alarm(BASE_TIME * 10); assert_se(barrier_place(&b)); assert_se(!barrier_sync(&b)); }), TEST_BARRIER_WAIT_SUCCESS(pid2)); /* * Test child exit with sleep * Same as test_barrier_exit but verifies the test really works due to the * child-exit. We add a usleep() which triggers the alarm in the parent and * causes the test to time out. */ TEST_BARRIER(test_barrier_no_exit, ({ sleep_for(BASE_TIME * 2); }), TEST_BARRIER_WAIT_SUCCESS(pid1), ({ set_alarm(BASE_TIME); assert_se(barrier_place(&b)); assert_se(!barrier_sync(&b)); }), TEST_BARRIER_WAIT_ALARM(pid2)); /* * Test pending exit against sync * The parent places a barrier *and* exits. The 20ms wait in the child * guarantees both are pending. However, our logic prefers pending barriers over * pending exit-abortions (unlike normal abortions), thus the wait_next() must * succeed, same for the sync_next() as our local barrier-count is smaller than * the remote. Once we place a barrier our count is equal, so the sync still * succeeds. Only if we place one more barrier, we're ahead of the remote, thus * we will fail due to HUP on the pipe. */ TEST_BARRIER(test_barrier_pending_exit, ({ set_alarm(BASE_TIME * 4); sleep_for(BASE_TIME * 2); assert_se(barrier_wait_next(&b)); assert_se(barrier_sync_next(&b)); assert_se(barrier_place(&b)); assert_se(barrier_sync_next(&b)); assert_se(barrier_place(&b)); assert_se(!barrier_sync_next(&b)); }), TEST_BARRIER_WAIT_SUCCESS(pid1), ({ assert_se(barrier_place(&b)); }), TEST_BARRIER_WAIT_SUCCESS(pid2)); int main(int argc, char *argv[]) { /* * This test uses real-time alarms and sleeps to test for CPU races * explicitly. This is highly fragile if your system is under load. We * already increased the BASE_TIME value to make the tests more robust, * but that just makes the test take significantly longer. Hence, * disable the test by default, so it will not break CI. */ if (argc < 2) return EXIT_TEST_SKIP; log_parse_environment(); log_open(); test_barrier_sync(); test_barrier_wait_next(); test_barrier_wait_next_twice(); test_barrier_wait_next_twice_sync(); test_barrier_wait_next_twice_local(); test_barrier_wait_next_twice_local_sync(); test_barrier_sync_next(); test_barrier_sync_next_local(); test_barrier_sync_next_local_abort(); test_barrier_wait_abortion(); test_barrier_wait_abortion_unmatched(); test_barrier_wait_abortion_local(); test_barrier_wait_abortion_local_unmatched(); test_barrier_exit(); test_barrier_no_exit(); test_barrier_pending_exit(); return 0; }