cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

leapcrash.c (2291B)

      1/* Demo leapsecond deadlock
      2 *              by: John Stultz (john.stultz@linaro.org)
      3 *              (C) Copyright IBM 2012
      4 *              (C) Copyright 2013, 2015 Linaro Limited
      5 *              Licensed under the GPL
      6 *
      7 * This test demonstrates leapsecond deadlock that is possible
      8 * on kernels from 2.6.26 to 3.3.
      9 *
     10 * WARNING: THIS WILL LIKELY HARD HANG SYSTEMS AND MAY LOSE DATA
     11 * RUN AT YOUR OWN RISK!
     12 *  To build:
     13 *	$ gcc leapcrash.c -o leapcrash -lrt
     14 */
     15
     16
     17
     18#include <stdio.h>
     19#include <stdlib.h>
     20#include <time.h>
     21#include <sys/time.h>
     22#include <sys/timex.h>
     23#include <string.h>
     24#include <signal.h>
     25#include "../kselftest.h"
     26
     27/* clear NTP time_status & time_state */
     28int clear_time_state(void)
     29{
     30	struct timex tx;
     31	int ret;
     32
     33	/*
     34	 * We have to call adjtime twice here, as kernels
     35	 * prior to 6b1859dba01c7 (included in 3.5 and
     36	 * -stable), had an issue with the state machine
     37	 * and wouldn't clear the STA_INS/DEL flag directly.
     38	 */
     39	tx.modes = ADJ_STATUS;
     40	tx.status = STA_PLL;
     41	ret = adjtimex(&tx);
     42
     43	tx.modes = ADJ_STATUS;
     44	tx.status = 0;
     45	ret = adjtimex(&tx);
     46
     47	return ret;
     48}
     49
     50/* Make sure we cleanup on ctrl-c */
     51void handler(int unused)
     52{
     53	clear_time_state();
     54	exit(0);
     55}
     56
     57
     58int main(void)
     59{
     60	struct timex tx;
     61	struct timespec ts;
     62	time_t next_leap;
     63	int count = 0;
     64
     65	setbuf(stdout, NULL);
     66
     67	signal(SIGINT, handler);
     68	signal(SIGKILL, handler);
     69	printf("This runs for a few minutes. Press ctrl-c to stop\n");
     70
     71	clear_time_state();
     72
     73
     74	/* Get the current time */
     75	clock_gettime(CLOCK_REALTIME, &ts);
     76
     77	/* Calculate the next possible leap second 23:59:60 GMT */
     78	next_leap = ts.tv_sec;
     79	next_leap += 86400 - (next_leap % 86400);
     80
     81	for (count = 0; count < 20; count++) {
     82		struct timeval tv;
     83
     84
     85		/* set the time to 2 seconds before the leap */
     86		tv.tv_sec = next_leap - 2;
     87		tv.tv_usec = 0;
     88		if (settimeofday(&tv, NULL)) {
     89			printf("Error: You're likely not running with proper (ie: root) permissions\n");
     90			return ksft_exit_fail();
     91		}
     92		tx.modes = 0;
     93		adjtimex(&tx);
     94
     95		/* hammer on adjtime w/ STA_INS */
     96		while (tx.time.tv_sec < next_leap + 1) {
     97			/* Set the leap second insert flag */
     98			tx.modes = ADJ_STATUS;
     99			tx.status = STA_INS;
    100			adjtimex(&tx);
    101		}
    102		clear_time_state();
    103		printf(".");
    104		fflush(stdout);
    105	}
    106	printf("[OK]\n");
    107	return ksft_exit_pass();
    108}