/*  $Id: get_mem_fbsd.c,v 1.1 2018/12/26 18:46:16 bch Exp $
 * 
 * Author: Christian Barthel <bch@online.de>
 */


#include <sys/types.h>	/* DEV_BSIZE MAXCOMLEN PZERO */
#include <sys/sysctl.h>

#include <unistd.h>
#include <kvm.h>

#include <X11/Xos.h>
#include <X11/Intrinsic.h>
#include <stdio.h>
#include <stdlib.h>
#include <err.h>
#include "MemStripChart.h"

static int pageshift = -1; 
static int pagesize  = 0;
static kvm_t *kd = 0;
#define pagetok(size) ((size) << pageshift)
#define LOG1024 10 

static unsigned int allmem_pages = 0; 

static void initPageShift(void)
{
	pagesize = getpagesize();
	size_t len = sizeof(allmem_pages);
	int mib[len];
	pageshift = 0;
	while (pagesize > 1) {
		pageshift++;
		pagesize >>= 1;
	}
	pageshift -= LOG1024;

	kd = kvm_open(NULL, "/dev/null" ,NULL, O_RDONLY, "kvm_open");

	if (sysctlbyname("vm.stats.vm.v_page_count", &allmem_pages, &len, NULL, 0) == -1)
			perror("sysctl");
#ifdef DEBUG
	printf("page_count: %d\n", allmem_pages);
#endif
}

static double getSwapFrac() 
{
		/* XXX Borrowed from top(1) code: */
		int n;
		struct kvm_swap swapary[1];
		static int pagesize = 0;
		static unsigned long swap_maxpages = 0;
		size_t sz = sizeof(swap_maxpages);

		int retavail = 0;
		int retfree = 0;


		n = kvm_getswapinfo(kd, swapary, 1, 0);
		if (n < 0 || swapary[0].ksw_total == 0)
				return (0);
		
		if (swap_maxpages == 0)
				sysctlbyname("vm.swap_maxpages", &swap_maxpages, &sz, NULL, 0);

		if ( swapary[0].ksw_total > swap_maxpages )
				swapary[0].ksw_total = swap_maxpages;
		
		retavail = swapary[0].ksw_total;
		retfree = swapary[0].ksw_total - swapary[0].ksw_used;

#ifdef DEBUG
		printf("swap: %d %d %d %d\n", retavail, retavail, swapary[0].ksw_total,
					 swapary[0].ksw_used);
#endif
		return (double)(retavail-retfree)/(double)retavail;
}

void GetMemLoadPoint(Widget w, caddr_t closure, caddr_t call_data)	
{
	MemStripChartCallbackData ret;
	int a, b;
	size_t sz = sizeof(int);
	double cache = 0;
	
	if (pageshift < 0) 
		initPageShift(); 

	sysctlbyname("vm.stats.vm.v_wire_count", &a, &sz, NULL, 0);
	ret.code = (double)a / (double)allmem_pages;

	sysctlbyname("vm.stats.vm.v_active_count", &a, &sz, NULL, 0);
	ret.buffer = (double)a / (double)allmem_pages;
	
	/* v_cache_count and v_inactive_count are treated similarly */
	sysctlbyname("vm.stats.vm.v_inactive_count", &a, &sz, NULL, 0);
	sysctlbyname("vm.stats.vm.v_cache_count", &b, &sz, NULL, 0);
	ret.cached = (double)(a + b) / allmem_pages;


	sysctlbyname("vm.stats.vm.v_free_count", &a, &sz, NULL, 0);
	ret.free = (double)a / allmem_pages;
	ret.swap = getSwapFrac();

#ifdef DEBUG
	printf("%u  %lf %lf  %lf %lf\n", allmem_pages, 
				 ret.code, ret.cached, ret.free, ret.swap);
#endif
	memcpy(call_data, &ret, sizeof(MemStripChartCallbackData));
}