Luna/apps/src/uptime.c

#include <stdio.h>
#include <time.h>

#define VALUE_SINGULAR_AT_ONE(v) v, v == 1 ? "" : "s"

int main()
{
    struct timespec tp;
    clock_gettime(CLOCK_MONOTONIC, &tp); // On Luna, CLOCK_MONOTONIC starts at boot.

    struct tm* time = gmtime(
        &tp.tv_sec); // just splitting the value into seconds, minutes, hours, days... not the best way to do it but ok.
    time->tm_year -= 70;

    if (time->tm_year)
    {
        printf("up for %d year%s, %d day%s, %d hour%s, %d minute%s, %d second%s\n",
               VALUE_SINGULAR_AT_ONE(time->tm_year), VALUE_SINGULAR_AT_ONE(time->tm_yday),
               VALUE_SINGULAR_AT_ONE(time->tm_hour), VALUE_SINGULAR_AT_ONE(time->tm_min),
               VALUE_SINGULAR_AT_ONE(time->tm_sec));
    }
    else if (time->tm_yday)
    {
        printf("up for %d day%s, %d hour%s, %d minute%s, %d second%s\n", VALUE_SINGULAR_AT_ONE(time->tm_yday),
               VALUE_SINGULAR_AT_ONE(time->tm_hour), VALUE_SINGULAR_AT_ONE(time->tm_min),
               VALUE_SINGULAR_AT_ONE(time->tm_sec));
    }
    else if (time->tm_hour)
    {
        printf("up for %d hour%s, %d minute%s, %d second%s\n", VALUE_SINGULAR_AT_ONE(time->tm_hour),
               VALUE_SINGULAR_AT_ONE(time->tm_min), VALUE_SINGULAR_AT_ONE(time->tm_sec));
    }
    else if (time->tm_min)
        printf("up for %d minute%s, %d second%s\n", VALUE_SINGULAR_AT_ONE(time->tm_min),
               VALUE_SINGULAR_AT_ONE(time->tm_sec));
    else
        printf("up for %d second%s\n", VALUE_SINGULAR_AT_ONE(time->tm_sec));
}