sys_linux.c

/*  WMBubble dockapp 1.2 - Linux specific code
 *  Copyright 2000, 2001 timecop@japan.co.jp
 *  
 *  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 2 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, write to the Free Software
 *  Foundation, Inc., 59 Temple Street #330, Boston, MA 02111-1307, USA.
 *
 */

#include <stdio.h>
#include <string.h>
#include <sys/utsname.h>
#include <inttypes.h>
#include "include/bubblemon.h"
#include "include/sys_include.h"

extern BubbleMonData bm;

/* returns current CPU load in percent, 0 to 100 */
int system_cpu(void) {
	unsigned int cpuload;
	u_int64_t load, total, oload, ototal;
	u_int64_t ab, ac, ad, ae;
	int i;
	FILE *stat;

	stat = fopen("/proc/stat", "r");
	/* first row: across all cores; first columns: "cpu"
	   subsequent columns:
    user: normal processes executing in user mode
    nice: niced processes executing in user mode
    system: processes executing in kernel mode
    idle: twiddling thumbs
    iowait: waiting for I/O to complete
    irq: servicing interrupts
    softirq: servicing softirqs

    for some reason we ignore iowait, irq, and softirq. is that reasonable?
 */
	if (fscanf(stat, "%*s %"PRIu64" %"PRIu64" %"PRIu64" %"PRIu64,
		   &ab, &ac, &ad, &ae) == EOF) {
		fprintf(stderr, "EOF when reading /proc/stat\n");
		return -1;
	}
	fclose(stat);

	/* Find out the CPU load */
	/* user + sys = load
	 * total = total */
	load = ab + ac + ad;	/* cpu.user + cpu.sys; */
	total = ab + ac + ad + ae;	/* cpu.total; */

	/* circular buffer; "i" is an index into a load history */
	i = bm.loadIndex;
	oload = bm.load[i];
	ototal = bm.total[i];

	bm.load[i] = load;
	bm.total[i] = total;
	bm.loadIndex = (i + 1) % bm.samples;

	/*
	  Because the load above is an accumulated value over time, and not the
	  current load, the current load percentage is calculated as the extra
	  amount of work that has been performed since the last sample.

	  In this case, we compare the current numbers to "bm.samples" ago.
	*/
	if (ototal == 0)		/* ototal == 0 means that this is the first time we get here */
		cpuload = 0;
	else if ((total - ototal) <= 0)
		cpuload = 100;
	else
		cpuload = (100 * (load - oload)) / (total - ototal);

	return cpuload;
}

void system_memory(void) {
	char *p;
	FILE *mem;

	/* put this in permanent storage instead of stack */
	static char meminfo[2048];

	/* we might as well get both swap and memory at the same time.
	 * sure beats opening the same file twice */
	mem = fopen("/proc/meminfo", "r");
	memset(meminfo, 0, sizeof(meminfo));
	if (fread(meminfo, 2048, 1, mem) < 2048) {
		if (ferror(mem)) {
			fprintf(stderr, "error reading /proc/meminfo\n");
			return;
		}
	}
	p = strstr(meminfo, "MemTotal");
	if (p) {
		sscanf(p, "MemTotal:%"PRIu64, &bm.mem_max);
		bm.mem_max <<= 10;

		p = strstr(p, "Active");
		if (p) {
			sscanf(p, "Active:%"PRIu64, &bm.mem_used);
			bm.mem_used <<= 10;

			p = strstr(p, "SwapTotal");
			if (p) {
				sscanf(p, "SwapTotal:%"PRIu64, &bm.swap_max);
				bm.swap_max <<= 10;

				p = strstr(p, "SwapFree");
				if (p) {
					sscanf(p, "SwapFree:%"PRIu64,
					       &bm.swap_used);
					bm.swap_used = bm.swap_max - (bm.swap_used << 10);
				}
			}
		}
	}
	fclose(mem);
}

void system_loadavg(void) {
	FILE *avg;
	avg = fopen("/proc/loadavg", "r");
	if (fscanf(avg, "%d.%d %d.%d %d.%d", &bm.loadavg[0].i, &bm.loadavg[0].f,
		   &bm.loadavg[1].i, &bm.loadavg[1].f,
		   &bm.loadavg[2].i, &bm.loadavg[2].f) == EOF) {
		fprintf(stderr, "EOF when reading /proc/loadavg\n");
		return;
	}
	fclose(avg);
}