06 timers

06_timers/Makefile

@@ -0,0 +1,7 @@
+CC=gcc
+SOURCES=main.c
+EXECUTABLE=user_abs_time
+
+all: $(SOURCES)
+	$(CC) $(SOURCES) -o $(EXECUTABLE)
+

06_timers/main.c

@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-3.0
+/**/
+#include <stdio.h>
+#include <time.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+int print_clock_gettime(clockid_t clock)
+{
+	const int bufsize = 50;
+	char buf[bufsize];
+	struct timespec now;
+	struct tm ts;
+
+	memset(buf, '\0', bufsize);
+	if (clock_gettime(clock, &now) == -1) {
+		perror("clock_gettime failure");
+		exit(EXIT_FAILURE);
+	}
+	gmtime_r(&now.tv_sec, &ts);
+	strftime(buf, bufsize, "%Y-%m-%d Time: %H:%M:%S.", &ts);
+	sprintf(buf, "%s%09lu", buf, now.tv_nsec);
+	printf("%s\n", buf);
+	if (clock_getres(clock, &now) == -1) {
+		perror("clock_getres failure");
+		exit(EXIT_FAILURE);
+	}
+	printf("  resolution: %10jd.%09ld\n\n",
+		(intmax_t) now.tv_sec, now.tv_nsec);
+	return 0;
+}
+
+int main(void)
+{
+	printf("=============================\n");
+	printf("CLOCK_REALTIME time: ");
+	print_clock_gettime(CLOCK_REALTIME);
+    #ifdef CLOCK_TAI
+		printf("=============================\n");
+		printf("CLOCK_TAI time: ");
+		print_clock_gettime(CLOCK_TAI);
+    #endif
+	return 0;
+}
+

06_timers/time_module/Makefile

@@ -0,0 +1,7 @@
+TARGET = get_time_module
+obj-m+=$(TARGET).o
+default:
+	$(MAKE) -C $(BUILD_KERNEL) M=$(CURDIR) modules
+
+clean:
+	$(MAKE) -C $(BUILD_KERNEL) M=$(CURDIR) clean

06_timers/time_module/get_time_module.c

@@ -0,0 +1,121 @@
+// SPDX-License-Identifier: GPL-3.0
+/**/
+
+#define pr_fmt(fmt) "%s: " fmt,  KBUILD_MODNAME
+#include <linux/kobject.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/ctype.h>
+
+#define LEN_STR 160
+
+static char buf_str[LEN_STR + 1];
+static struct timespec64 r_last_time;
+static struct timespec64 a_last_time;
+static bool first_read = 1;
+
+struct timespec64 delta_time(struct timespec64 start, struct timespec64 stop)
+{
+	struct timespec64 delta;
+
+	delta.tv_sec = stop.tv_sec-start.tv_sec;
+	delta.tv_nsec = stop.tv_nsec-start.tv_nsec;
+	if (delta.tv_nsec < 0)
+		delta.tv_nsec += 1000000000;
+	return delta;
+}
+
+static ssize_t relation_delay_show(struct kobject *kobj,
+	struct kobj_attribute *attr, char *buf)
+{
+	int ret = 0;
+	struct timespec64 r_new_time, delta;
+
+	if (first_read) {
+		ret = scnprintf(buf, PAGE_SIZE,
+		"RELATION DELAY FROM LAST READING \t 0s\n");
+		ktime_get_real_ts64(&a_last_time);
+		ktime_get_ts64(&r_new_time);
+		first_read = 0;
+		return ret;
+	}
+	ktime_get_real_ts64(&a_last_time);
+	ktime_get_ts64(&r_new_time);
+	delta = delta_time(r_last_time, r_new_time);
+	ret = scnprintf(buf, PAGE_SIZE,
+		"RELATION DELAY FROM LAST READING \t %lld.%09lds\n",
+		(s64)delta.tv_sec, delta.tv_nsec);
+	r_last_time = r_new_time;
+	return ret;
+}
+
+static ssize_t absolute_delay_show(struct kobject *kobj,
+	struct kobj_attribute *attr, char *buf)
+{
+	int ret = 0;
+
+	if (first_read) {
+		ret = scnprintf(buf, PAGE_SIZE,
+		"ABSOLUTE TIME OF LAST READING \t 0s\n");
+		ktime_get_real_ts64(&a_last_time);
+		ktime_get_ts64(&r_last_time);
+		first_read = 0;
+		return ret;
+	}
+	ktime_get_ts64(&r_last_time);
+	ret = scnprintf(buf, PAGE_SIZE,
+		"ABSOLUTE TIME OF LAST READING \t %lld.%09lds\n",
+		(s64)a_last_time.tv_sec, a_last_time.tv_nsec);
+	ktime_get_real_ts64(&a_last_time);
+	return ret;
+}
+
+static struct kobj_attribute relation_delay_attribute =
+	__ATTR(relation_delay, 0444, relation_delay_show, NULL);
+
+static struct kobj_attribute absolute_delay_attribute =
+	__ATTR(absolute_delay, 0444, absolute_delay_show, NULL);
+
+static struct attribute *attrs[] = {
+	&relation_delay_attribute.attr,
+	&absolute_delay_attribute.attr,
+	NULL,
+};
+
+static struct attribute_group attr_group = {
+	.attrs = attrs,
+};
+
+static struct kobject *store_delay_kobj;
+
+static int __init store_delay_module_init(void)
+{
+	int retval;
+
+	memset(buf_str, '\0', LEN_STR+1);
+	pr_debug("loading started\n");
+	store_delay_kobj = kobject_create_and_add("PASSED_DELAY", kernel_kobj);
+	if (!store_delay_kobj)
+		return -ENOMEM;
+	retval = sysfs_create_group(store_delay_kobj, &attr_group);
+	if (retval)
+		kobject_put(store_delay_kobj);
+
+	return retval;
+}
+
+static void __exit store_delay_module_exit(void)
+{
+	kobject_put(store_delay_kobj);
+	pr_info("module exited\n");
+}
+
+module_init(store_delay_module_init);
+module_exit(store_delay_module_exit);
+
+MODULE_AUTHOR("Malakhova.Maryna <maryna.malakhova@globallogic.com>");
+MODULE_DESCRIPTION("Store time delay module");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("0.1");