/* $Id: plugin_uptime.c 840 2007-09-09 12:17:42Z michael $
 * $URL: https://ssl.bulix.org/svn/lcd4linux/trunk/plugin_uptime.c $
 *
 * plugin for uptime
 *
 * Copyright (C) 2003 Michael Reinelt <michael@reinelt.co.at>
 * Copyright (C) 2004 The LCD4Linux Team <lcd4linux-devel@users.sourceforge.net>
 *
 * This file is part of LCD4Linux.
 *
 * LCD4Linux 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 2, or (at your option)
 * any later version.
 *
 * LCD4Linux 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, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

/* 
 * exported functions:
 *
 * int plugin_init_uptime (void)
 *  adds functions for uptime
 *
 */


#include "config.h"

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <fcntl.h>

#include "debug.h"
#include "plugin.h"

static int fd = -2;


static char *itoa(char *buffer, const size_t size, unsigned int value)
{
    char *p;

    /* sanity checks */
    if (buffer == NULL || size < 2)
	return (NULL);

    /* p points to last char */
    p = buffer + size - 1;

    /* set terminating zero */
    *p = '\0';

    do {
	*--p = value % 10 + '0';
	value = value / 10;
    } while (value != 0 && p > buffer);

    return p;
}


char *struptime(const unsigned int uptime, const char *format)
{
    static char string[256];
    const char *src;
    char *dst;
    int len, size;

    src = format;
    dst = string;
    len = 0;

    /* leave room for terminating zero  */
    size = sizeof(string) - 1;

    while (len < size) {

	if (*src == '%') {
	    src++;

	    if (strchr("sSmMhHd", *src) != NULL) {
		char buffer[12], *s;
		unsigned int value = 0;
		int leading_zero = 0;
		switch (*src++) {
		case 's':
		    value = uptime;
		    break;
		case 'S':
		    value = uptime % 60;
		    leading_zero = 1;
		    break;
		case 'm':
		    value = uptime / 60;
		    break;
		case 'M':
		    value = (uptime / 60) % 60;
		    leading_zero = 1;
		    break;
		case 'h':
		    value = uptime / 60 / 60;
		    break;
		case 'H':
		    value = (uptime / 60 / 60) % 24;
		    leading_zero = 1;
		    break;
		case 'd':
		    value = uptime / 60 / 60 / 24;
		    break;
		}

		if (leading_zero && value < 10) {
		    len++;
		    *dst++ = '0';
		}

		s = itoa(buffer, sizeof(buffer), value);
		while (len < size && *s != '\0') {
		    len++;
		    *dst++ = *s++;
		}

	    } else if (*src == '%') {
		len++;
		*dst++ = '%';

	    } else {
		len += 2;
		*dst++ = '%';
		*dst++ = *src++;
	    }

	} else {
	    len++;
	    *dst++ = *src;
	    if (*src++ == '\0')
		break;
	}
    }

    /* enforce terminating zero */
    if (len >= size && *(dst - 1) != '\0') {
	len++;
	*dst = '\0';
    }

    return string;
}


double getuptime(void)
{
    char buffer[36];
    int i;

    if (fd == -2)
	fd = open("/proc/uptime", O_RDONLY);
    if (fd < 0)
	return -1;

    lseek(fd, 0, SEEK_SET);

    i = read(fd, buffer, sizeof(buffer) - 1);
    if (i < 0)
	return -1;

    buffer[i - 1] = '\0';

    /* ignore the 2nd value from /proc/uptime */
    return strtod(buffer, NULL);
}


static void my_uptime(RESULT * result, const int argc, RESULT * argv[])
{
    int age;
    static double uptime = 0.0;
    static struct timeval last_value;
    struct timeval now;

    if (argc > 1) {
	error("uptime(): wrong number of parameters");
	SetResult(&result, R_STRING, "");
	return;
    }

    gettimeofday(&now, NULL);

    age = (now.tv_sec - last_value.tv_sec) * 1000 + (now.tv_usec - last_value.tv_usec) / 1000;
    /* reread every 100 msec only */
    if (fd == -2 || age == 0 || age > 100) {
	uptime = getuptime();
	if (uptime < 0.0) {
	    error("parse(/proc/uptime) failed!");
	    SetResult(&result, R_STRING, "");
	    return;
	}

	last_value = now;
    }

    if (argc == 0) {
	SetResult(&result, R_NUMBER, &uptime);
    } else {
	SetResult(&result, R_STRING, struptime(uptime, R2S(argv[0])));
    }

    return;

}

int plugin_init_uptime(void)
{
    AddFunction("uptime", -1, my_uptime);
    return 0;
}

void plugin_exit_uptime(void)
{
    if (fd > 0)
	close(fd);
    fd = -2;
}