/**

 * sts.c: show time stamp

 * Copyright (C) 2010 Markus Broeker

 */

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <math.h>

#include <time.h>

#include <errno.h>

void usage (char *name)

{

    printf ("Usage: %s STAMP [BOOT-STAMP]\n", name);

    exit (EXIT_FAILURE);

}

time_t parse (char *buf)

{

    time_t sec = 0;

    time_t milli = 0;

    double value;

    if (sscanf (buf, "%ld.%ld", &sec, &milli) != 2) {

        fprintf (stderr, "  sec: %ld, ", sec);

        fprintf (stderr, "milli: %ld\n", milli);

    }

    value = (milli / 1000000);

    return sec + (time_t) (floor (value));

}

time_t getboottime ()

{

    char buf[80];

    time_t now = time (NULL);

    FILE *f = fopen ("/proc/uptime", "r");

    if (fgets (buf, sizeof (buf), f) == NULL) {

        perror ("FOPEN");

        exit (errno);

    }

    fclose (f);

    return now - parse (buf);

}

int main (int argc, char **argv)

{

    time_t boot;

    time_t stamp = 0;

    time_t diff;

    if (argc < 2)

        usage (argv[0]);

    stamp = parse (argv[1]);

    if (argc == 3) {

        boot = parse (argv[2]);

    } else

        boot = getboottime ();

    diff = boot + stamp;

    printf ("%s: %s", argv[1], ctime (&diff));

    return EXIT_SUCCESS;

}