[LTP] [PATCH v2 1/2] syscalls/clock_settime01.c: create syscall clock_settime

[Cyril Hrubis <chrubis@suse.cz>]

Hi!
> new file mode 100644
> index 000000000..97d720fa2
> --- /dev/null
> +++ b/testcases/kernel/syscalls/clock_settime/clock_settime01.c
> @@ -0,0 +1,122 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2018 Linaro Limited. All rights reserved.
> + * Author: Rafael David Tinoco <rafael.tinoco@linaro.org>
> + */
> +
> +/*
> + * Basic test for clock_settime(2) on REALTIME clock:
> + *
> + *      1) advance DELTA_SEC seconds
> + *      2) go backwards DELTA_SEC seconds
> + *
> + * Accept DELTA_PER deviation on both (specially going backwards).
> + */
> +
> +#include "config.h"
> +#include "tst_test.h"
> +#include "lapi/syscalls.h"
> +
> +#define DELTA_SEC 10	/* 10 seconds delta    */
> +#define DELTA_PER 0.1	/* 1 percent deviation */
> +
> +static struct timespec real_begin, mono_begin, mono_end;
> +
> +static void clock_elapsed(struct timespec *begin, struct timespec *end,
> +		struct timespec *elapsed)
> +{
> +	elapsed->tv_sec = end->tv_sec - begin->tv_sec;
> +	elapsed->tv_nsec = end->tv_nsec - begin->tv_nsec;

If you do this the elapsed may end up in non-normalized state, i.e.
elapsed->tv_nsec may end up negative.

We do have all kinds of inline functions for conversion and arimetic in
tst_timer.h so there is no point of rolling your own here.

> +}
> +
> +static void clock_return(void)
                      ^
		      I would have named this restore, but that is very
		      minor.

> +{
> +	static struct timespec elapsed, adjust;
> +
> +	clock_elapsed(&mono_begin, &mono_end, &elapsed);
> +
> +	adjust.tv_sec = real_begin.tv_sec + elapsed.tv_sec;
> +	adjust.tv_nsec = real_begin.tv_nsec + elapsed.tv_nsec;

We should normalize the addition here as well, i.e. carry over to
seconds if the number of nanoseconds gets greater than 1s.

Ideally we should add a function to add two timespec structures into the
tst_timer.h header (in a separate patch).

> +	if (clock_settime(CLOCK_REALTIME, &adjust) != 0)
> +		tst_res(TBROK | TTERRNO, "could restore realtime clock");
> +}
> +
> +static void clock_fixnow(void)
> +{
> +	if (clock_gettime(CLOCK_MONOTONIC_RAW, &mono_end) != 0)
> +		tst_res(TBROK | TTERRNO, "could not get elapsed time");

We should make sure here that both real_begin and mono_begin were set
before we attempt to restore the system time. A restore_time flag se to
1 after we successfully read both will do.

> +	clock_return();
> +}
> +
> +static void setup(void)
> +{
> +	/* save initial monotonic time to restore it when needed */
> +
> +	if (clock_gettime(CLOCK_REALTIME, &real_begin) != 0)
> +		tst_res(TBROK | TTERRNO, "could not get initial real time");
> +
> +	if (clock_gettime(CLOCK_MONOTONIC_RAW, &mono_begin) != 0)
> +		tst_res(TBROK | TTERRNO, "couldn't get initial monotonic time");
                  ^
		  This should have been tst_brk() doing tst_res() with
		  TBROK does not make much sense.

Also we do have tst_safe_clocks.h, if you include that you can use
SAFE_CLOCK_GETTIME() instead.

Overall the idea of restoring wall clock using monotonic timer is a good
one, maybe we should even move this code to a library so that all tests
that change wall clock would need just set restore_wallclock flag in the
tst_test structure...

> +}
> +
> +static void cleanup(void)
> +{
> +	clock_fixnow();
> +}
> +
> +static void verify_clock_settime(void)
> +{
> +	static struct timespec begin, change, end, elapsed;
> +
> +	/* test 01: move forward */
> +
> +	if (clock_gettime(CLOCK_REALTIME, &begin) != 0)
> +		tst_res(TBROK | TTERRNO, "could not get realtime at the begin");
> +
> +	change.tv_sec = begin.tv_sec + DELTA_SEC;
> +
> +	if (clock_settime(CLOCK_REALTIME, &change) != 0)
> +		tst_res(TBROK | TTERRNO, "could not set realtime change");
> +
> +	if (clock_gettime(CLOCK_REALTIME, &end) != 0)
> +		tst_res(TBROK | TTERRNO, "could not get realtime after change");

Here as well.

> +	clock_elapsed(&begin, &end, &elapsed);
> +
> +	if (elapsed.tv_sec < (float) (DELTA_SEC - (DELTA_SEC * DELTA_PER)))

It would be much easier to just use tst_timespec_diff_ms() and check
that the result is in reasonable range. I.e. check lower bound as well.

> +		tst_res(TFAIL, "clock_settime(2): could not advance time");
> +	else
> +		tst_res(TPASS, "clock_settime(2): was able to advance time");
> +
> +	/* test 02: move backward */
> +
> +	if (clock_gettime(CLOCK_REALTIME, &begin) != 0)
> +		tst_res(TBROK | TTERRNO, "could not get realtime at the begin");
> +
> +	change.tv_sec = begin.tv_sec - DELTA_SEC;
> +
> +	if (clock_settime(CLOCK_REALTIME, &change) != 0)
> +		tst_res(TBROK | TTERRNO, "could not set realtime change");
> +
> +	if (clock_gettime(CLOCK_REALTIME, &end) != 0)
> +		tst_res(TBROK | TTERRNO, "could not get realtime after change");
> +
> +	clock_elapsed(&begin, &end, &elapsed);
> +
> +	elapsed.tv_sec = ~elapsed.tv_sec;
> +	elapsed.tv_nsec = ~elapsed.tv_nsec;
> +
> +	if (elapsed.tv_sec < (float) (DELTA_SEC - (DELTA_SEC * DELTA_PER)))
> +		tst_res(TFAIL, "clock_settime(2): could not recede time");
> +	else
> +		tst_res(TPASS, "clock_settime(2): was able to recede time");

Here as well.

> +}
> +
> +static struct tst_test test = {
> +	.setup = setup,
> +	.test_all = verify_clock_settime,
> +	.cleanup = cleanup,
> +	.needs_root = 1,
> +};
>
> diff --git a/testcases/kernel/syscalls/clock_settime/clock_settime02.c b/testcases/kernel/syscalls/clock_settime/clock_settime02.c
> new file mode 100644
> index 000000000..710f37219
> --- /dev/null
> +++ b/testcases/kernel/syscalls/clock_settime/clock_settime02.c
> @@ -0,0 +1,171 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2018 Linaro Limited. All rights reserved.
> + * Author: Rafael David Tinoco <rafael.tinoco@linaro.org>
> + */
> +
> +/*
> + * Basic tests for errors of clock_settime(2) on different clock types.
> + */
> +
> +#include "config.h"
> +#include "tst_test.h"
> +#include "lapi/syscalls.h"
> +
> +#define DELTA_SEC 10
> +#define NSEC_PER_SEC (1000000000L)
> +#define MAX_CLOCKS 16
> +
> +static struct timespec clock_realtime_saved;
> +
> +struct test_case {
> +	clockid_t type;
> +	struct timespec newtime;
> +	int exp_err;
> +	int replace;
> +};
> +
> +struct test_case tc[] = {
> +	{				/* case 01: REALTIME: timespec NULL   */
> +	 .type = CLOCK_REALTIME,
> +	 .newtime.tv_sec = -2,
> +	 .exp_err = EFAULT,
> +	 .replace = 1,
> +	 },
> +	{				/* case 02: REALTIME: tv_sec = -1     */
> +	 .type = CLOCK_REALTIME,
> +	 .newtime.tv_sec = -1,
> +	 .exp_err = EINVAL,
> +	 .replace = 1,
> +	 },
> +	{				/* case 03: REALTIME: tv_nsec = -1    */
> +	 .type = CLOCK_REALTIME,
> +	 .newtime.tv_nsec = -1,
> +	 .exp_err = EINVAL,
> +	 .replace = 1,
> +	 },
> +	{				/* case 04: REALTIME: tv_nsec = 1s+1  */
> +	 .type = CLOCK_REALTIME,
> +	 .newtime.tv_nsec = NSEC_PER_SEC + 1,
> +	 .exp_err = EINVAL,
> +	 .replace = 1,
> +	 },
> +	{				/* case 05: MONOTONIC		      */
> +	 .type = CLOCK_MONOTONIC,
> +	 .exp_err = EINVAL,
> +	 },
> +	{				/* case 06: MAXCLOCK		      */
> +	 .type = MAX_CLOCKS,
> +	 .exp_err = EINVAL,
> +	 },
> +	{				/* case 07: MAXCLOCK+1		      */
> +	 .type = MAX_CLOCKS + 1,
> +	 .exp_err = EINVAL,
> +	 },
> +	/* Linux specific */
> +	{				/* case 08: CLOCK_MONOTONIC_COARSE    */
> +	 .type = CLOCK_MONOTONIC_COARSE,
> +	 .exp_err = EINVAL,
> +	 },
> +	{				/* case 09: CLOCK_MONOTONIC_RAW       */
> +	 .type = CLOCK_MONOTONIC_RAW,
> +	 .exp_err = EINVAL,
> +	 },
> +	{				/* case 10: CLOCK_BOOTTIME	      */
> +	 .type = CLOCK_BOOTTIME,
> +	 .exp_err = EINVAL,
> +	 },
> +	{				/* case 11: CLOCK_PROCESS_CPUTIME_ID  */
> +	 .type = CLOCK_PROCESS_CPUTIME_ID,
> +	 .exp_err = EINVAL,
> +	 },
> +	{				/* case 12: CLOCK_THREAD_CPUTIME_ID   */
> +	 .type = CLOCK_THREAD_CPUTIME_ID,
> +	 .exp_err = EINVAL,
> +	 },
> +};
> +
> +/*
> + * Some tests may cause libc to segfault when passing bad arguments.
> + */
> +static int sys_clock_settime(clockid_t clk_id, struct timespec *tp)
> +{
> +	return tst_syscall(__NR_clock_settime, clk_id, tp);
> +}
> +
> +static int sys_clock_gettime(clockid_t clk_id, struct timespec *tp)
> +{
> +	return tst_syscall(__NR_clock_gettime, clk_id, tp);
> +}
> +
> +static void cleanup(void)
> +{
> +	/* restore realtime clock */
> +
> +	if (sys_clock_settime(CLOCK_REALTIME, &clock_realtime_saved) < 0)
> +		tst_res(TBROK | TTERRNO, "clock_settime(2): could not set "
> +				"current time back");
> +}
> +
> +static void setup(void)
> +{
> +	if (sys_clock_gettime(CLOCK_REALTIME, &clock_realtime_saved) < 0)
> +		tst_res(TBROK | TTERRNO, "clock_gettime(2): could not get "
> +				"current time");
> +}
> +
> +static void verify_clock_settime(unsigned int i)
> +{
> +	struct timespec spec, *specptr;
> +
> +	if (tc[i].replace == 0) {
> +
> +		/* add 1 sec to test clock */
> +
> +		specptr = &spec;
> +		specptr->tv_sec = clock_realtime_saved.tv_sec + 1;
> +		specptr->tv_nsec = clock_realtime_saved.tv_nsec;
> +
> +	} else {
> +
> +		/* bad pointer case */
> +
> +		if (tc[i].newtime.tv_sec == -2)
> +			specptr = tst_get_bad_addr(cleanup);
> +
> +		/* use given values */
> +
> +		else {

Still curly braces missing here, but that is minor.

And maybe we just need to turn the newtime into a pointer in the tcases
structure. Then you can initialize global variable to current time +
epsion and use pointer to it or even initialize it inline as:

static struct timespec valid_time;

struct test_case tc[] = {
	{
	 .type = CLOCK_REALTIME,
	 .exp_err = EFAULT,
	},
	{
	 .type = CLOCK_REALTIME;
	 .newtime = &valid_time;
	 .exp_err = EINVAL,
	{
	 .type = CLOCK_REALTIME,
	 .newtime = &(struct timespec){},
	 .exp_err = EINVAL,
	 .replace = 1,
	},
	...
};

And we can loop in the test setup and set NULL address to the result of
tst_get_bad_addr() as well.

> +			specptr = &spec;
> +			specptr->tv_sec = tc[i].newtime.tv_sec;
> +			specptr->tv_nsec = tc[i].newtime.tv_nsec;
> +		}
> +	}
> +
> +	TEST(sys_clock_settime(tc[i].type, specptr));
> +
> +	if (TST_RET == -1) {
> +
> +		if (tc[i].exp_err == TST_ERR) {
> +
> +			tst_res(TPASS, "clock_settime(2): failed as expected");
> +
> +		} else {
> +			tst_res(TFAIL | TTERRNO, "clock_settime(2): "
> +					"failed with different error");
> +		}
> +
> +		return;
> +	}
> +
> +	tst_res(TFAIL | TTERRNO, "clock_settime(2): clock type %d failed",
> +			tc[i].type);
> +}
> +
> +static struct tst_test test = {
> +	.setup = setup,
> +	.test = verify_clock_settime,
> +	.cleanup = cleanup,
> +	.tcnt = ARRAY_SIZE(tc),
> +	.needs_root = 1,
> +};
> -- 
> 2.20.0.rc1
> 

-- 
Cyril Hrubis
chrubis@suse.cz