micro-utils/src/procps/uptime/uptime.c

#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <stdlib.h>
#include <time.h>
#include "config.h"

#if defined(CLOCK_BOOTTIME)
	#define CLOCK CLOCK_BOOTTIME
#elif defined(CLOCK_UPTIME)
	#define CLOCK CLOCK_UPTIME
#elif defined(__APPLE__)
	#define CLOCK CLOCK_MONOTONIC
#endif

int main(void) {

	/* Now date */
	time_t current_secs;
	time(&current_secs);

	struct tm *current_time = localtime(&current_secs);
	printf("%02d:%02d:%02d  ", current_time->tm_hour, current_time->tm_min, current_time->tm_sec);

	/* How long system has beep up */
	struct timespec uptime;
	if (clock_gettime(CLOCK, &uptime) != -1) {
		int days = uptime.tv_sec / 86400;
		int hours = uptime.tv_sec / 3600;
		int mins = (uptime.tv_sec / 60) - (uptime.tv_sec / 3600 * 60);


		printf("up:");

		if (days > 0)
			printf(" %d days", days);

		else if (hours > 0)
			printf(" %d hours", hours);

		printf(" %d mins", mins);
	}

#ifdef UPTIME_LOADAVG
	/* Print 1, 5 and 15 minute load averages */
	double avg[3] = {0, 0, 0};

	if (getloadavg(avg, sizeof(avg) / sizeof(avg[0])) < 0) {
		fprintf(stderr, "uptime: %s\n", strerror(errno));
		return 1;
	}

	printf("  load average: %.2f %.2f %.2f", avg[0], avg[1], avg[2]);

#endif

	putchar('\n');
	return 0;
}