[src/trunk]: src/tests/lib/libc/sys t_clock_gettime: Add test for PR kern/57512.

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/c54c3ea935a5
branches:  trunk
changeset: 377354:c54c3ea935a5
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sat Jul 08 14:05:51 2023 +0000

description:
t_clock_gettime: Add test for PR kern/57512.

diffstat:

 tests/lib/libc/sys/t_clock_gettime.c |  93 ++++++++++++++++++++++++++++++++++-
 1 files changed, 89 insertions(+), 4 deletions(-)

diffs (126 lines):

diff -r e9c387c75ffa -r c54c3ea935a5 tests/lib/libc/sys/t_clock_gettime.c
--- a/tests/lib/libc/sys/t_clock_gettime.c      Sat Jul 08 13:59:05 2023 +0000
+++ b/tests/lib/libc/sys/t_clock_gettime.c      Sat Jul 08 14:05:51 2023 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: t_clock_gettime.c,v 1.3 2017/01/13 21:30:41 christos Exp $ */
+/* $NetBSD: t_clock_gettime.c,v 1.4 2023/07/08 14:05:51 riastradh Exp $ */
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -58,17 +58,19 @@
 #include <sys/cdefs.h>
 __COPYRIGHT("@(#) Copyright (c) 2008\
  The NetBSD Foundation, inc. All rights reserved.");
-__RCSID("$NetBSD: t_clock_gettime.c,v 1.3 2017/01/13 21:30:41 christos Exp $");
+__RCSID("$NetBSD: t_clock_gettime.c,v 1.4 2023/07/08 14:05:51 riastradh Exp $");
 
 #include <sys/param.h>
+
+#include <sys/ioctl.h>
 #include <sys/sysctl.h>
 
-
 #include <atf-c.h>
 #include <errno.h>
+#include <fcntl.h>
 #include <limits.h>
+#include <stdint.h>
 #include <stdio.h>
-#include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
 #include <time.h>
@@ -204,10 +206,93 @@ ATF_TC_BODY(clock_gettime_real, tc)
        RL(sysctlbyname(TC_HARDWARE, NULL, 0, save, strlen(save)));
 }
 
+static void
+waste_user_time(void)
+{
+       static char buf[4*4096];
+
+       arc4random_buf(buf, sizeof(buf));
+}
+
+static void __unused
+waste_system_time(void)
+{
+       static char buf[4*4096];
+       int fd[2];
+       int i, n;
+
+       RL(pipe2(fd, O_NONBLOCK));
+       RL(n = ioctl(fd[1], FIONSPACE));
+       n = MIN(MAX(0, n), sizeof(buf));
+       for (i = 0; i < 16; i++) {
+               RL(write(fd[1], buf, n));
+               RL(read(fd[0], buf, n));
+       }
+       RL(close(fd[0]));
+       RL(close(fd[1]));
+}
+
+static void
+check_monotonicity(const char *clockname, clockid_t clockid,
+    void (*waste_time)(void))
+{
+       static const struct timespec maxtime = {5, 0};
+       struct timespec mono_t0, t0, mono_d;
+
+       RL(clock_gettime(CLOCK_MONOTONIC, &mono_t0));
+       RL(clock_gettime(clockid, &t0));
+
+       do {
+               struct timespec t1, mono_t1;
+
+               (*waste_time)();
+
+               RL(clock_gettime(clockid, &t1));
+               ATF_CHECK_MSG(timespeccmp(&t0, &t1, <=),
+                   "clock %s=0x%jx went backwards t0=%jd.%09ld t1=%jd.%09ld",
+                   clockname, (uintmax_t)clockid,
+                   (intmax_t)t0.tv_sec, t0.tv_nsec,
+                   (intmax_t)t1.tv_sec, t1.tv_nsec);
+
+               t0 = t1;
+
+               RL(clock_gettime(CLOCK_MONOTONIC, &mono_t1));
+               timespecsub(&mono_t1, &mono_t0, &mono_d);
+       } while (timespeccmp(&mono_d, &maxtime, <));
+}
+
+ATF_TC(clock_gettime_process_cputime_is_monotonic);
+ATF_TC_HEAD(clock_gettime_process_cputime_is_monotonic, tc)
+{
+       atf_tc_set_md_var(tc, "descr",
+           "Checks that CLOCK_PROCESS_CPUTIME_ID is monotonic");
+}
+ATF_TC_BODY(clock_gettime_process_cputime_is_monotonic, tc)
+{
+       check_monotonicity("CLOCK_PROCESS_CPUTIME_ID",
+           CLOCK_PROCESS_CPUTIME_ID, &waste_user_time);
+}
+
+ATF_TC(clock_gettime_thread_cputime_is_monotonic);
+ATF_TC_HEAD(clock_gettime_thread_cputime_is_monotonic, tc)
+{
+       atf_tc_set_md_var(tc, "descr",
+           "Checks that CLOCK_THREAD_CPUTIME_ID is monotonic");
+}
+ATF_TC_BODY(clock_gettime_thread_cputime_is_monotonic, tc)
+{
+       atf_tc_expect_fail("PR kern/57512: clock_gettime"
+           "(CLOCK_THREAD_CPUTIME_ID) sometimes goes backwards");
+       check_monotonicity("CLOCK_THREAD_CPUTIME_ID",
+           CLOCK_THREAD_CPUTIME_ID, &waste_user_time);
+}
+
 ATF_TP_ADD_TCS(tp)
 {
 
        ATF_TP_ADD_TC(tp, clock_gettime_real);
+       ATF_TP_ADD_TC(tp, clock_gettime_process_cputime_is_monotonic);
+       ATF_TP_ADD_TC(tp, clock_gettime_thread_cputime_is_monotonic);
 
        return atf_no_error();
 }