text: // SPDX-License-Identifier: GPL-2.0-or-later
  /*
   * Copyright (C) 2002 Andi Kleen
   * Copyright (C) 2017 Cyril Hrubis <chrubis@suse.cz>
   */
  
  /*
   * DESCRIPTION
   *	Check if gettimeofday is monotonous
   *
   * ALGORITHM
   *	Call gettimeofday() to get a t1 (fist value)
   *	call it again to get t2, see if t2 < t1, set t2 = t1, repeat for 10 sec
   */
  
  #include <stdint.h>
  #include <sys/time.h>
  #include <stdlib.h>
  #include <unistd.h>
  #include <time.h>
  #include <errno.h>
  
  #include "tst_test.h"
  #include "lapi/syscalls.h"
  
  static volatile sig_atomic_t done;
  static char *str_rtime;
  static int rtime = 10;
  
  static struct tst_option options[] = {
  	{"T:", &str_rtime, "-T len   Test iteration runtime in seconds"},
  	{NULL, NULL, NULL},
  };
  
  static void breakout(int sig)
  {
  	done = sig;
  }
  
  static void verify_gettimeofday(void)
  {
  	struct timeval tv1, tv2;
  	unsigned long long cnt = 0;
  
  	done = 0;
  
  	alarm(rtime);
  
  	if (tst_syscall(__NR_gettimeofday, &tv1, NULL))
  		tst_brk(TFAIL | TERRNO, "gettimeofday() failed");
  
  	while (!done) {
  		if (tst_syscall(__NR_gettimeofday, &tv2, NULL))
  			tst_brk(TFAIL | TERRNO, "gettimeofday() failed");
  
  		if (tv2.tv_sec < tv1.tv_sec ||
  		    (tv2.tv_sec == tv1.tv_sec && tv2.tv_usec < tv1.tv_usec)) {
  			tst_res(TFAIL,
  				"Time is going backwards: old %jd.%jd vs new %jd.%jd!",
  				(intmax_t) tv1.tv_sec, (intmax_t) tv1.tv_usec,
  				(intmax_t) tv2.tv_sec, (intmax_t) tv2.tv_usec);
  			return;
  		}
  
  		tv1 = tv2;
  		cnt++;
  	}
  
  	tst_res(TINFO, "gettimeofday() called %llu times", cnt);
  	tst_res(TPASS, "gettimeofday() monotonous in %i seconds", rtime);
  }
  
  static void setup(void)
  {
  	if (str_rtime) {
  		rtime = atoi(str_rtime);
  		if (rtime <= 0)
  			tst_brk(TBROK, "Invalid runtime '%s'", str_rtime);
  		tst_set_timeout(rtime + 60);
  	}
  
  	SAFE_SIGNAL(SIGALRM, breakout);
  }
  
  static struct tst_test test = {
  	.setup = setup,
  	.options = options,
  	.test_all = verify_gettimeofday,
  };
  