sortix--sortix/utils/uptime.cpp

/*******************************************************************************

    Copyright(C) Jonas 'Sortie' Termansen 2011, 2012, 2013.

    This program is free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by the Free
    Software Foundation, either version 3 of the License, or (at your option)
    any later version.

    This program is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
    more details.

    You should have received a copy of the GNU General Public License along with
    this program. If not, see <http://www.gnu.org/licenses/>.

    uptime.cpp
    Tell how long the system has been running.

*******************************************************************************/

#include <errno.h>
#include <error.h>
#include <stdio.h>
#include <stdint.h>
#include <unistd.h>
#include <time.h>

size_t Seconds(uintmax_t usecs)
{
	return (usecs / (1000ULL * 1000ULL)) % (60ULL);
}

size_t Minutes(uintmax_t usecs)
{
	return (usecs / (1000ULL * 1000ULL * 60ULL)) % (60ULL);
}

size_t Hours(uintmax_t usecs)
{
	return (usecs / (1000ULL * 1000ULL * 60ULL * 60ULL)) % (24ULL);
}

size_t Days(uintmax_t usecs)
{
	return usecs / (1000ULL * 1000ULL * 60ULL * 60ULL * 24ULL);
}

void PrintElement(size_t num, const char* single, const char* multiple)
{
	static const char* prefix = "";
	if ( !num ) { return; }
	const char* str = (num>1) ? multiple : single;
	printf("%s%zu %s", prefix, num, str);
	prefix = ", ";
}

int main(int /*argc*/, char* /*argv*/[])
{
	struct timespec uptime;
	if ( clock_gettime(CLOCK_BOOT, &uptime) < 0 )
		error(1, errno, "clock_gettime(CLOCK_BOOT)");

	uintmax_t usecssinceboot = uptime.tv_sec * 1000000ULL +
	                           uptime.tv_nsec / 1000ULL;
	PrintElement(Days(usecssinceboot), "day", "days");
	PrintElement(Hours(usecssinceboot), "hour", "hours");
	PrintElement(Minutes(usecssinceboot), "min", "mins");
	PrintElement(Seconds(usecssinceboot), "sec", "secs");
	printf("\n");

	return 0;
}