varqox · April 27, 2019 10:52 · Apr 27, 2019 · Apr 27, 2019 · Apr 27, 2019 · Apr 27, 2019
diff --git a/time_test.c b/time_test.c
@@ -146,11 +146,11 @@ void test3() {
 		pid = fork();
 		if (pid == 0) { // Child
 			// Sync 0
-			sleep_for(0.2, 0.2); // Tricky: gets current time, then after 0.1 sec time gets distorted - time stops, then on the second read time the time point will be set
+			sleep_for(0.2, 0.2); // Tricky: gets current time, then after 0.1 sec time gets distorted - time stops, then on the second read of time the time point will be set
 			// Sync 1
 			sleep_for(1, 0);
 			// Sync 2
-			sleep_for(1, 2.0); // Tricky: gets current time (frozen for 1 second, then waits 1 second but in the meanwhile settimeofday() is called and time point is reset, so after sleeping for 1 second, the second read of current time will return current time and set time point to its value)
+			sleep_for(1, 2.0); // Tricky: gets current time (frozen for 1 second, then waits 1 second but in the meanwhile settimeofday() is called and time point is reset, so after sleeping for 1 second, the second read of current time will return current time and set the time point to its value)
 			// Sync 3
 			mysleep(0.2);
 			// Sync 4

diff --git a/time_test.c b/time_test.c
@@ -262,7 +262,7 @@ void test5() {
 // Checks timepoint setting
 void test6() {
 	if (fork() == 0) {
-		// New proses is not distorted and no time point is set
+		// New process is not distorted and no time point is set
 		struct timeval beg, end;
 		assert(0 == gettimeofday(&beg, NULL));
 
@@ -280,7 +280,7 @@ void test6() {
 	assert_wait();
 
 	if (fork() == 0) {
-		// New proses is not distorted and no time point is set
+		// New process is not distorted and no time point is set
 		struct timeval beg, end;
 		assert(0 == gettimeofday(&beg, NULL));
 
@@ -302,7 +302,7 @@ void test6() {
 	assert_wait();
 
 	if (fork() == 0) {
-		// New proses is not distorted and no time point is set
+		// New process is not distorted and no time point is set
 		struct timeval beg, end;
 		assert(0 == gettimeofday(&beg, NULL));
 
@@ -318,6 +318,27 @@ void test6() {
 		_exit(0);
 	}
 	assert_wait();
+
+	if (fork() == 0) {
+		// New process is not distorted and no time point is set
+		struct timeval beg, end;
+
+		distort_my_time_from_child(4);
+		sleep_for(0.4, 0.1);
+
+		assert(0 == gettimeofday(&beg, NULL));
+		resettimeofday(); // Time point is reseted
+
+		mysleep(1);
+
+		assert(0 == gettimeofday(&end, NULL)); // Time point is set now
+		check_diff(beg, end, 1);
+
+		sleep_for(0.4, 0.1);
+
+		_exit(0);
+	}
+	assert_wait();
 }
 
 int main() {

diff --git a/time_test.c b/time_test.c
@@ -217,7 +217,7 @@ void test4() {
 
 	distort_my_time_from_child(2);
 	resettimeofday();
-	
+
 	sleep_for(1, 0.5);
 
 	assert(0 == gettimeofday(&beg, NULL));
@@ -259,7 +259,7 @@ void test5() {
 	check_diff(beg, end, 1);
 }
 
-// Checks timepoint setting be the first call to distort_time
+// Checks timepoint setting
 void test6() {
 	if (fork() == 0) {
 		// New proses is not distorted and no time point is set

diff --git a/time_test.c b/time_test.c
@@ -262,6 +262,7 @@ void test5() {
 // Checks timepoint setting be the first call to distort_time
 void test6() {
 	if (fork() == 0) {
+		// New proses is not distorted and no time point is set
 		struct timeval beg, end;
 		assert(0 == gettimeofday(&beg, NULL));
 
@@ -279,9 +280,10 @@ void test6() {
 	assert_wait();
 
 	if (fork() == 0) {
+		// New proses is not distorted and no time point is set
 		struct timeval beg, end;
 		assert(0 == gettimeofday(&beg, NULL));
-		
+
 		sleep_for(0.5, 0.5);
 		distort_my_time_from_child(1);
 		sleep_for(0.5, 0.5);
@@ -300,6 +302,7 @@ void test6() {
 	assert_wait();
 
 	if (fork() == 0) {
+		// New proses is not distorted and no time point is set
 		struct timeval beg, end;
 		assert(0 == gettimeofday(&beg, NULL));
 

diff --git a/time_test.c b/time_test.c
@@ -22,8 +22,11 @@ struct timeval subtract(struct timeval a, struct timeval b) {
 }
 
 void mysleep(double seconds) {
-	assert(0 == sleep(seconds));
-	assert(0 == usleep((seconds - (int)seconds) * 1e6));
+	// sleep() and usleep() call nanosleep() with second argument causing nanosleep() to call gettimeofday()
+	struct timespec ts;
+	ts.tv_sec = seconds;
+	ts.tv_nsec = (seconds - (int)seconds) * 1e9;
+	assert(0 == nanosleep(&ts, NULL)); // This does not call gettimeofday()
 }
 
 void print_current_time_from_tv(struct timeval tv) {
@@ -67,13 +70,20 @@ void do_sleep_for(double seconds, double expected_diff, int line) {
 	do_check_diff_impl(before, after, expected_diff, "awaken after");
 }
 
+void assert_wait() {
+	int status;
+	assert(wait(&status) != -1);
+	assert(WIFEXITED(status));
+	assert(WEXITSTATUS(status) == 0);
+}
+
 void distort_my_time_from_child(int scale) {
 	if (fork() == 0) {
 		assert(distort_time(getppid(), scale) == 0);
 		_exit(0);
 	}
 
-	wait(NULL);
+	assert_wait();
 }
 
 void distort_time_of(pid_t pid, int scale) {
@@ -161,7 +171,7 @@ void test3() {
 			exit(0);
 		}
 
-		wait(NULL);
+		assert_wait();
 		exit(0);
 	}
 
@@ -198,7 +208,7 @@ void test3() {
 	mysleep(1);
 	// Sync 10
 
-	wait(NULL);
+	assert_wait();
 }
 
 // Checks distorting time of parent by 1
@@ -222,7 +232,7 @@ void test4() {
 	assert(0 == gettimeofday(&beg, NULL));
 	distort_my_time_from_child(1);
 	assert(0 == gettimeofday(&end, NULL));
-	check_diff(beg, end, 0.5);	
+	check_diff(beg, end, 0.5);
 }
 
 // Checks unsuccessful calls to PM_CLOCK_SETTIME
@@ -249,12 +259,71 @@ void test5() {
 	check_diff(beg, end, 1);
 }
 
+// Checks timepoint setting be the first call to distort_time
+void test6() {
+	if (fork() == 0) {
+		struct timeval beg, end;
+		assert(0 == gettimeofday(&beg, NULL));
+
+		sleep_for(0.5, 0.5);
+		distort_my_time_from_child(0);
+		mysleep(0.5);
+
+		assert(0 == gettimeofday(&end, NULL)); // Time point is set now
+		check_diff(beg, end, 1);
+
+		sleep_for(0.5, 0);
+
+		_exit(0);
+	}
+	assert_wait();
+
+	if (fork() == 0) {
+		struct timeval beg, end;
+		assert(0 == gettimeofday(&beg, NULL));
+
+		sleep_for(0.5, 0.5);
+		distort_my_time_from_child(1);
+		sleep_for(0.5, 0.5);
+
+		assert(0 == gettimeofday(&end, NULL));
+		check_diff(beg, end, 1);
+
+		sleep_for(0.5, 0.5);
+
+		distort_my_time_from_child(0); // Time point does not change
+		assert(0 == gettimeofday(&end, NULL));
+		check_diff(beg, end, 0.5);
+
+		_exit(0);
+	}
+	assert_wait();
+
+	if (fork() == 0) {
+		struct timeval beg, end;
+		assert(0 == gettimeofday(&beg, NULL));
+
+		sleep_for(0.5, 0.5);
+		distort_my_time_from_child(2);
+		mysleep(0.5);
+
+		assert(0 == gettimeofday(&end, NULL));
+		check_diff(beg, end, 1);
+
+		sleep_for(0.5, 0.25);
+
+		_exit(0);
+	}
+	assert_wait();
+}
+
 int main() {
 	test1();
 	test2();
 	test3();
 	test4();
 	test5();
+	test6();
 
 	printf("\033[1;32mAll tests passed!\033[m\n");
 }
diff --git a/time_test.c b/time_test.c
@@ -0,0 +1,260 @@
+// Krzysztof Małysa
+#include <assert.h>
+#include <errno.h>
+#include <math.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <time.h>
+#include <unistd.h>
+
+struct timeval subtract(struct timeval a, struct timeval b) {
+	struct timeval res = {a.tv_sec - b.tv_sec, a.tv_usec - b.tv_usec};
+	if (res.tv_usec < 0) {
+		--res.tv_sec;
+		res.tv_usec += 1000000;
+	}
+
+	return res;
+}
+
+void mysleep(double seconds) {
+	assert(0 == sleep(seconds));
+	assert(0 == usleep((seconds - (int)seconds) * 1e6));
+}
+
+void print_current_time_from_tv(struct timeval tv) {
+	printf("current time: %.6lf\n", tv.tv_sec + tv.tv_usec / 1e6);
+	fflush(stdout);
+}
+
+void print_current_time() {
+	struct timeval tv;
+	assert(0 == gettimeofday(&tv, NULL));
+	print_current_time_from_tv(tv);
+}
+
+void do_check_diff_impl(struct timeval beg, struct timeval end, double expected_diff, const char* msg) {
+	struct timeval diff = subtract(end, beg);
+	double ddiff = diff.tv_sec + diff.tv_usec / 1e6;
+	printf("%s: %.6lf\n", msg, ddiff);
+	print_current_time_from_tv(end);
+	fflush(stdout);
+	assert(fabs(ddiff - expected_diff) < 0.04);
+}
+
+#define check_diff(beg, end, exp_df) do_check_diff(beg, end, exp_df, __LINE__)
+void do_check_diff(struct timeval beg, struct timeval end, double expected_diff, int line) {
+	printf("======= check from line: %i =======\n", line);
+	do_check_diff_impl(beg, end, expected_diff, "time diff");
+}
+
+#define sleep_for(sec, ed) do_sleep_for(sec, ed, __LINE__)
+void do_sleep_for(double seconds, double expected_diff, int line) {
+	printf("======= check from line: %i =======\n", line);
+	fflush(stdout);
+	struct timeval before, after;
+	assert(0 == gettimeofday(&before, NULL));
+	print_current_time_from_tv(before);
+	printf("sleeping for %.6lf seconds...\n", seconds);
+	fflush(stdout);
+	mysleep(seconds);
+
+	assert(0 == gettimeofday(&after, NULL));
+	do_check_diff_impl(before, after, expected_diff, "awaken after");
+}
+
+void distort_my_time_from_child(int scale) {
+	if (fork() == 0) {
+		assert(distort_time(getppid(), scale) == 0);
+		_exit(0);
+	}
+
+	wait(NULL);
+}
+
+void distort_time_of(pid_t pid, int scale) {
+	assert(distort_time(pid, scale) == 0);
+}
+
+pid_t some_nonexistent_pid() {
+	pid_t p = 1;
+	while ((errno = 0, kill(p, 0)) == 0 || errno != ESRCH)
+		++p;
+
+	return p;
+}
+
+// Checks argument checking
+void test1() {
+	sleep_for(1, 1);
+	assert(distort_time(getpid(), 2) == EPERM);
+
+	assert(distort_time(some_nonexistent_pid(), 2) == EINVAL);
+
+	assert(distort_time(5, 2) == EPERM); // 5 == pid of /service/pm
+
+	assert(distort_time(getppid(), 2) == 0);
+}
+
+// Checks distorting time of ancestor
+void test2() {
+	distort_my_time_from_child(4);
+
+	sleep_for(4, 1);
+	sleep_for(1, 0.25);
+
+	distort_my_time_from_child(0);
+	sleep_for(1, 0);
+	sleep_for(2, 0);
+
+	distort_my_time_from_child(255);
+	sleep_for(12, 12.0/255);
+
+	distort_my_time_from_child(256); // Overflow
+	sleep_for(1, 0);
+
+	distort_my_time_from_child(1);
+	sleep_for(1, 1);
+}
+
+void resettimeofday() {
+	struct timeval curr;
+	assert(0 == gettimeofday(&curr, NULL));
+	assert(0 == settimeofday(&curr, NULL));
+}
+
+// Checks distorting time of parent
+void test3() {
+	distort_my_time_from_child(1);
+
+	pid_t pid = fork();
+	if (pid == 0) { // Child
+		pid = fork();
+		if (pid == 0) { // Child
+			// Sync 0
+			sleep_for(0.2, 0.2); // Tricky: gets current time, then after 0.1 sec time gets distorted - time stops, then on the second read time the time point will be set
+			// Sync 1
+			sleep_for(1, 0);
+			// Sync 2
+			sleep_for(1, 2.0); // Tricky: gets current time (frozen for 1 second, then waits 1 second but in the meanwhile settimeofday() is called and time point is reset, so after sleeping for 1 second, the second read of current time will return current time and set time point to its value)
+			// Sync 3
+			mysleep(0.2);
+			// Sync 4
+			sleep_for(1, 4);
+			// Sync 5
+			mysleep(0.2);
+			// Sync 6
+			sleep_for(1, 255);
+			// Sync 7
+			mysleep(0.2);
+			// Sync 8
+			sleep_for(2, 0);
+			// Sync 9
+			distort_my_time_from_child(1);
+			sleep_for(1, 1);
+			// Sync 10
+
+			exit(0);
+		}
+
+		wait(NULL);
+		exit(0);
+	}
+
+	pid += 1; // A dirty hack to get the child's child's pid
+	// Sync 0
+	mysleep(0.1);
+	distort_time_of(pid, 0);
+	mysleep(0.1);
+	// Sync 1
+	mysleep(1);
+	// Sync 2
+	mysleep(0.5);
+	resettimeofday();
+	mysleep(0.5);
+	// Sync 3
+	mysleep(0.1);
+	distort_time_of(pid, 4);
+	mysleep(0.1);
+	// Sync 4
+	mysleep(1);
+	// Sync 5
+	mysleep(0.1);
+	distort_time_of(pid, 255);
+	mysleep(0.1);
+	// Sync 6
+	mysleep(1);
+	// Sync 7
+	mysleep(0.1);
+	distort_time_of(pid, 256); // Overflow
+	mysleep(0.1);
+	// Sync 8
+	mysleep(2);
+	// Sync 9
+	mysleep(1);
+	// Sync 10
+
+	wait(NULL);
+}
+
+// Checks distorting time of parent by 1
+void test4() {
+	struct timeval beg, end;
+
+	distort_my_time_from_child(2);
+	resettimeofday();
+
+	sleep_for(1, 0.5);
+
+	assert(0 == gettimeofday(&beg, NULL));
+	distort_my_time_from_child(4);
+	assert(0 == gettimeofday(&end, NULL));
+	check_diff(beg, end, -0.25);
+
+	distort_my_time_from_child(2);
+	resettimeofday();
+	sleep_for(1, 0.5);
+
+	assert(0 == gettimeofday(&beg, NULL));
+	distort_my_time_from_child(1);
+	assert(0 == gettimeofday(&end, NULL));
+	check_diff(beg, end, 0.5);	
+}
+
+// Checks unsuccessful calls to PM_CLOCK_SETTIME
+void test5() {
+	struct timeval beg, end;
+
+	distort_my_time_from_child(0);
+	resettimeofday();
+
+	sleep_for(1, 0);
+
+	assert(0 == gettimeofday(&beg, NULL));
+	struct timespec ts;
+	ts.tv_sec = beg.tv_sec + 1;
+	ts.tv_nsec = beg.tv_usec * 1000;
+
+	assert(-1 == clock_settime(CLOCK_MONOTONIC, &ts));
+	assert(errno == EINVAL);
+	assert(0 == gettimeofday(&end, NULL)); // Time should not have been reset
+	check_diff(beg, end, 0);
+
+	assert(0 == clock_settime(CLOCK_REALTIME, &ts));
+	assert(0 == gettimeofday(&end, NULL)); // Time should have been reset
+	check_diff(beg, end, 1);
+}
+
+int main() {
+	test1();
+	test2();
+	test3();
+	test4();
+	test5();
+
+	printf("\033[1;32mAll tests passed!\033[m\n");
+}
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