#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/unistd.h>
#include <sys/stat.h>

int main(){
  int uptime_fd = open("/proc/uptime", O_RDONLY, 0600);
  if(uptime_fd == -1){
    printf("Impossible to retrieve /proc/uptime file");
    return -1;
  }
  
  // Read the content of /proc/uptime
  
  char buffer[64];
  if(read(uptime_fd, buffer, sizeof(char)*64) == -1){
    printf("Impossible to read /proc/uptime content");
    return -1;
  }
  
  int uptime = atoi(buffer);
  
  // Transform uptime into hours, days, mins, and seconds
  
  int updays = uptime / 86400;
  int uphours = (uptime - (updays * 86400)) / 3600;
  int upmins = (uptime - (updays * 86400) - (uphours * 3600)) / 60;
  int upseconds = (uptime - (updays * 86400) - (uphours * 3600) - (upmins * 60));
  
  printf("Days: %d Hours: %d Minutes: %d Seconds: %d \n", updays, uphours, upmins, upseconds);
  close(uptime_fd);
  return 0;
}