selftests/timens: Check for right timens offsets after fork and exec

clock_nanosleep

exec

gettime_perf

gettime_perf_cold

procfs

TEST_GEN_PROGS := timens timerfd timer clock_nanosleep procfs

TEST_GEN_PROGS := timens timerfd timer clock_nanosleep procfs exec

TEST_GEN_PROGS_EXTENDED := gettime_perf

CFLAGS := -Wall -Werror -pthread

// SPDX-License-Identifier: GPL-2.0

#define _GNU_SOURCE

#include <errno.h>

#include <fcntl.h>

#include <sched.h>

#include <stdio.h>

#include <stdbool.h>

#include <sys/stat.h>

#include <sys/syscall.h>

#include <sys/types.h>

#include <sys/wait.h>

#include <time.h>

#include <unistd.h>

#include <time.h>

#include <string.h>

#include "log.h"

#include "timens.h"

#define OFFSET (36000)

int main(int argc, char *argv[])

{

	struct timespec now, tst;

	int status, i;

	pid_t pid;

	if (argc > 1) {

		if (sscanf(argv[1], "%ld", &now.tv_sec) != 1)

			return pr_perror("sscanf");

		for (i = 0; i < 2; i++) {

			_gettime(CLOCK_MONOTONIC, &tst, i);

			if (abs(tst.tv_sec - now.tv_sec) > 5)

				return pr_fail("%ld %ld\n", now.tv_sec, tst.tv_sec);

		}

		return 0;

	}

	nscheck();

	ksft_set_plan(1);

	clock_gettime(CLOCK_MONOTONIC, &now);

	if (unshare_timens())

		return 1;

	if (_settime(CLOCK_MONOTONIC, OFFSET))

		return 1;

	for (i = 0; i < 2; i++) {

		_gettime(CLOCK_MONOTONIC, &tst, i);

		if (abs(tst.tv_sec - now.tv_sec) > 5)

			return pr_fail("%ld %ld\n",

					now.tv_sec, tst.tv_sec);

	}

	if (argc > 1)

		return 0;

	pid = fork();

	if (pid < 0)

		return pr_perror("fork");

	if (pid == 0) {

		char now_str[64];

		char *cargv[] = {"exec", now_str, NULL};

		char *cenv[] = {NULL};

		/* Check that a child process is in the new timens. */

		for (i = 0; i < 2; i++) {

			_gettime(CLOCK_MONOTONIC, &tst, i);

			if (abs(tst.tv_sec - now.tv_sec - OFFSET) > 5)

				return pr_fail("%ld %ld\n",

						now.tv_sec + OFFSET, tst.tv_sec);

		}

		/* Check for proper vvar offsets after execve. */

		snprintf(now_str, sizeof(now_str), "%ld", now.tv_sec + OFFSET);

		execve("/proc/self/exe", cargv, cenv);

		return pr_perror("execve");

	}

	if (waitpid(pid, &status, 0) != pid)

		return pr_perror("waitpid");

	if (status)

		ksft_exit_fail();

	ksft_test_result_pass("exec\n");

	ksft_exit_pass();

	return 0;

}