libgtop/sysdeps/freebsd/swap.c

/* $Id$ */

/* Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.
   This file is part of the Gnome Top Library.
   Contributed by Martin Baulig <martin@home-of-linux.org>, April 1998.

   The Gnome Top Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The Gnome Top Library 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <glibtop.h>
#include <glibtop/error.h>
#include <glibtop/swap.h>

#include <glibtop/xmalloc.h>

#include <glibtop_suid.h>

#include <sys/conf.h>
#include <sys/rlist.h>
#include <sys/vmmeter.h>

static const unsigned long _glibtop_sysdeps_swap =
(1 << GLIBTOP_SWAP_TOTAL) + (1 << GLIBTOP_SWAP_USED) +
(1 << GLIBTOP_SWAP_FREE) + (1 << GLIBTOP_SWAP_PAGEIN) +
(1 << GLIBTOP_SWAP_PAGEOUT);

/* nlist structure for kernel access */
static struct nlist nlst [] = {
#define VM_SWAPLIST	0
	{ "_swaplist" },/* list of free swap areas */
#define VM_SWDEVT	1
	{ "_swdevt" },	/* list of swap devices and sizes */
#define VM_NSWAP	2
	{ "_nswap" },	/* size of largest swap device */
#define VM_NSWDEV	3
	{ "_nswdev" },	/* number of swap devices */
#define VM_DMMAX	4
	{ "_dmmax" },	/* maximum size of a swap block */
	{ 0 }
};

/* Init function. */

void
glibtop_init_swap_p (glibtop *server)
{
	server->sysdeps.swap = _glibtop_sysdeps_swap;

	if (kvm_nlist (server->machine.kd, nlst) != 0)
		glibtop_error_io_r (server, "kvm_nlist");
}

/* Provides information about swap usage. */

/*
 * This function is based on a program called swapinfo written
 * by Kevin Lahey <kml@rokkaku.atl.ga.us>.
 */

void
glibtop_get_swap_p (glibtop *server, glibtop_swap *buf)
{
	char *header;
	int hlen, nswap, nswdev, dmmax;
	int i, div, avail, nfree, npfree, used;
	struct swdevt *sw;
	long blocksize, *perdev;
	struct rlist head;
	struct rlisthdr swaplist;
	struct rlist *swapptr;
	size_t sw_size;
	u_long ptr;

	/* To get `pagein' and `pageout'. */
	struct vmmeter vmm;
        static int swappgsin = -1;
	static int swappgsout = -1;

	glibtop_init_p (server, (1 << GLIBTOP_SYSDEPS_SWAP), 0);
	
	memset (buf, 0, sizeof (glibtop_swap));

	/* This is used to get the `pagein' and `pageout' members. */
	
	if (kvm_read (server->machine.kd, nlst[0].n_value,
		      &vmm, sizeof (vmm)) != sizeof (vmm))
		glibtop_error_io_r (server, "kvm_read (cnt)");
	
        if (swappgsin < 0) {
		buf->pagein = 0;
		buf->pageout = 0;
	} else {
		buf->pagein = vmm.v_swappgsin - swappgsin;
		buf->pageout = vmm.v_swappgsout - swappgsout;
	}

        swappgsin = vmm.v_swappgsin;
	swappgsout = vmm.v_swappgsout;

	/* Size of largest swap device. */

	if (kvm_read (server->machine.kd, nlst[VM_NSWAP].n_value,
		      &nswap, sizeof (nswap)) != sizeof (nswap))
		glibtop_error_io_r (server, "kvm_read (nswap)");

	/* Number of swap devices. */

	if (kvm_read (server->machine.kd, nlst[VM_NSWDEV].n_value,
		      &nswdev, sizeof (nswdev)) != sizeof (nswdev))
		glibtop_error_io_r (server, "kvm_read (nswdev)");

	/* Maximum size of a swap block. */

	if (kvm_read (server->machine.kd, nlst[VM_DMMAX].n_value,
		      &dmmax, sizeof (dmmax)) != sizeof (dmmax))
		glibtop_error_io_r (server, "kvm_read (dmmax)");

	/* List of free swap areas. */

	if (kvm_read (server->machine.kd, nlst[VM_SWAPLIST].n_value,
		      &swaplist, sizeof (swaplist)) != sizeof (swaplist))
		glibtop_error_io_r (server, "kvm_read (swaplist)");

	/* Kernel offset of list of swap devices and sizes. */

	if (kvm_read (server->machine.kd, nlst[VM_SWDEVT].n_value,
		      &ptr, sizeof (ptr)) != sizeof (ptr))
		glibtop_error_io_r (server, "kvm_read (swaplist)");

	/* List of swap devices and sizes. */

	sw_size = nswdev * sizeof (*sw);
	sw = glibtop_malloc_r (server, sw_size);

	if (kvm_read (server->machine.kd, ptr, sw, sw_size) != sw_size)
		glibtop_error_io_r (server, "kvm_read (*swdevt)");

	perdev = glibtop_malloc (nswdev * sizeof (*perdev));

	/* Count up swap space. */

	nfree = 0;
	memset (perdev, 0, nswdev * sizeof(*perdev));

	swapptr = swaplist.rlh_list;

	while (swapptr) {
		int	top, bottom, next_block;

		if (kvm_read (server->machine.kd, (int) swapptr, &head,
			      sizeof (struct rlist)) != sizeof (struct rlist))
			glibtop_error_io_r (server, "kvm_read (swapptr)");

		top = head.rl_end;
		bottom = head.rl_start;

		nfree += top - bottom + 1;

		/*
		 * Swap space is split up among the configured disks.
		 *
		 * For interleaved swap devices, the first dmmax blocks
		 * of swap space some from the first disk, the next dmmax
		 * blocks from the next, and so on up to nswap blocks.
		 *
		 * The list of free space joins adjacent free blocks,
		 * ignoring device boundries.  If we want to keep track
		 * of this information per device, we'll just have to
		 * extract it ourselves.
		 */
		while (top / dmmax != bottom / dmmax) {
			next_block = ((bottom + dmmax) / dmmax);
			perdev[(bottom / dmmax) % nswdev] +=
				next_block * dmmax - bottom;
			bottom = next_block * dmmax;
		}
		perdev[(bottom / dmmax) % nswdev] +=
			top - bottom + 1;

		swapptr = head.rl_next;
	}

	header = getbsize (&hlen, &blocksize);

	div = blocksize / 512;
	avail = npfree = 0;
	for (i = 0; i < nswdev; i++) {
		int xsize, xfree;

		/*
		 * Don't report statistics for partitions which have not
		 * yet been activated via swapon(8).
		 */
		if (!(sw[i].sw_flags & SW_FREED))
			continue;

		/* The first dmmax is never allocated to avoid trashing of
		 * disklabels
		 */
		xsize = sw[i].sw_nblks - dmmax;
		xfree = perdev[i];
		used = xsize - xfree;
		npfree++;
		avail += xsize;
	}

	/*
	 * If only one partition has been set up via swapon(8), we don't
	 * need to bother with totals.
	 */
	used = avail - nfree;

	glibtop_free_r (server, sw);
	glibtop_free_r (server, perdev);

	buf->used = used;
	buf->free = avail;

	buf->total = used + avail;
	buf->flags = _glibtop_sysdeps_swap;
}