xref: /third_party/ltp/testcases/kernel/syscalls/times/times03.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) International Business Machines Corp., 2001
 * Copyright (C) 2017 Cyril Hrubis <chrubis@suse.cz>
 */
/*
 * DESCRIPTION
 *	Testcase to check the basic functionality of the times() system call.
 *
 * ALGORITHM
 *	This testcase checks the values that times(2) system call returns.
 *	Start a process, and spend some CPU time by performing a spin in
 *	a for-loop. Then use the times() system call, to determine the
 *	cpu time/sleep time, and other statistics.
 *
 * History
 *	07/2001 John George
 */

#include <sys/types.h>
#include <sys/times.h>
#include <errno.h>
#include <sys/wait.h>
#include <time.h>
#include <signal.h>
#include <stdlib.h>

#include "tst_test.h"

static volatile int timeout;

static void sighandler(int signal)
{
	if (signal == SIGALRM)
		timeout = 1;
}

static volatile int k;

static void work(void)
{
	int i, j;

	while (!timeout)
		for (i = 0; i < 10000; i++)
			for (j = 0; j < 100; j++)
				k = i * j;
	timeout = 0;
}

static void generate_utime(void)
{
	alarm(1);
	work();
}

static void generate_stime(void)
{
	time_t start_time, end_time;
	struct tms buf;

	/*
	 * At least some CPU time must be used in system space. This is
	 * achieved by executing the times(2) call for
	 * at least 2 secs. This logic makes it independent
	 * of the processor speed.
	 */
	start_time = time(NULL);
	for (;;) {
		if (times(&buf) == -1)
			tst_res(TFAIL | TERRNO, "times failed");
		end_time = time(NULL);
		if ((end_time - start_time) > 2)
			return;
	}
}

static void verify_times(void)
{
	int pid;
	struct tms buf1, buf2, buf3;

	if (times(&buf1) == -1)
		tst_brk(TBROK | TERRNO, "times()");

	if (buf1.tms_utime > 5)
		tst_res(TFAIL, "buf1.tms_utime = %li", buf1.tms_utime);
	else
		tst_res(TPASS, "buf1.tms_utime <= 5");

	if (buf1.tms_stime > 5)
		tst_res(TFAIL, "buf1.tms_stime = %li", buf1.tms_stime);
	else
		tst_res(TPASS, "buf1.tms_stime <= 5");

	generate_utime();
	generate_stime();

	if (times(&buf2) == -1)
		tst_brk(TBROK | TERRNO, "times()");

	if (buf2.tms_utime == 0)
		tst_res(TFAIL, "buf2.tms_utime = 0");
	else
		tst_res(TPASS, "buf2.tms_utime = %li", buf2.tms_utime);

	if (buf1.tms_utime >= buf2.tms_utime) {
		tst_res(TFAIL, "buf1.tms_utime (%li) >= buf2.tms_utime (%li)",
			buf1.tms_utime, buf2.tms_utime);
	} else {
		tst_res(TPASS, "buf1.tms_utime (%li) < buf2.tms_utime (%li)",
			buf1.tms_utime, buf2.tms_utime);
	}

	if (buf2.tms_stime == 0)
		tst_res(TFAIL, "buf2.tms_stime = 0");
	else
		tst_res(TPASS, "buf2.tms_stime = %li", buf2.tms_stime);

	if (buf1.tms_stime >= buf2.tms_stime) {
		tst_res(TFAIL, "buf1.tms_stime (%li) >= buf2.tms_stime (%li)",
			buf1.tms_stime, buf2.tms_stime);
	} else {
		tst_res(TPASS, "buf1.tms_stime (%li) < buf2.tms_stime (%li)",
			buf1.tms_stime, buf2.tms_stime);
	}

	if (buf2.tms_cutime != 0)
		tst_res(TFAIL, "buf2.tms_cutime = %li", buf2.tms_cutime);
	else
		tst_res(TPASS, "buf2.tms_cutime = 0");

	if (buf2.tms_cstime != 0)
		tst_res(TFAIL, "buf2.tms_cstime = %li", buf2.tms_cstime);
	else
		tst_res(TPASS, "buf2.tms_cstime = 0");

	pid = SAFE_FORK();

	if (!pid) {
		generate_utime();
		generate_stime();
		exit(0);
	}

	SAFE_WAITPID(pid, NULL, 0);

	if (times(&buf3) == -1)
		tst_brk(TBROK | TERRNO, "times()");

	if (buf2.tms_utime > buf3.tms_utime) {
		tst_res(TFAIL, "buf2.tms_utime (%li) > buf3.tms_utime (%li)",
			buf2.tms_utime, buf3.tms_utime);
	} else {
		tst_res(TPASS, "buf2.tms_utime (%li) <= buf3.tms_utime (%li)",
			buf2.tms_utime, buf3.tms_utime);
	}

	if (buf2.tms_stime > buf3.tms_stime) {
		tst_res(TFAIL, "buf2.tms_stime (%li) > buf3.tms_stime (%li)",
			buf2.tms_stime, buf3.tms_stime);
	} else {
		tst_res(TPASS, "buf2.tms_stime (%li) <= buf3.tms_stime (%li)",
			buf2.tms_stime, buf3.tms_stime);
	}

	if (buf3.tms_cutime == 0)
		tst_res(TFAIL, "buf3.tms_cutime = 0");
	else
		tst_res(TPASS, "buf3.tms_cutime = %ld", buf3.tms_cutime);

	if (buf3.tms_cstime == 0)
		tst_res(TFAIL, "buf3.tms_cstime = 0");
	else
		tst_res(TPASS, "buf3.tms_cstime = %ld", buf3.tms_cstime);

	exit(0);
}

/*
 * Run the test in a child to reset times in case of -i option.
 */
static void do_test(void)
{
	int pid = SAFE_FORK();

	if (!pid)
		verify_times();
}

static void setup(void)
{
	SAFE_SIGNAL(SIGALRM, sighandler);
}

static struct tst_test test = {
	.setup = setup,
	.forks_child = 1,
	.test_all = do_test,
};