/*	$NetBSD: dkstats.c,v 1.21 2004/02/13 11:36:24 wiz Exp $	*/

/*
 * Copyright (c) 1996 John M. Vinopal
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed for the NetBSD Project
 *      by John M. Vinopal.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/sched.h>
#include <sys/sysctl.h>
#include <sys/time.h>
#include <sys/disk.h>

#include <err.h>
#include <fcntl.h>
#include <kvm.h>
#include <limits.h>
#include <nlist.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "dkstats.h"

static struct nlist namelist[] = {
#define	X_TK_NIN	0
	{ "_tk_nin" },		/* tty characters in */
#define	X_TK_NOUT	1
	{ "_tk_nout" },		/* tty characters out */
#define	X_HZ		2
	{ "_hz" },		/* ticks per second */
#define	X_STATHZ	3
	{ "_stathz" },
#define	X_DISK_COUNT	4
	{ "_disk_count" },	/* number of disks */
#define	X_DISKLIST	5
	{ "_disklist" },	/* TAILQ of disks */
	{ NULL },
};

/* Structures to hold the statistics. */
struct _disk	cur, last;

/* Kernel pointers: nlistf and memf defined in calling program. */
static kvm_t	*kd = NULL;
extern char	*nlistf;
extern char	*memf;
extern int	hz;

/* Pointer to list of disks. */
static struct disk		*dk_drivehead = NULL;
/* sysctl hw.diskstats buffer. */
static struct disk_sysctl	*dk_drives = NULL;

/* Backward compatibility references. */
int		dk_ndrive = 0;
int		*dk_select;
char		**dr_name;

#define	KVM_ERROR(_string) do {						\
	warnx("%s", (_string));						\
	errx(1, "%s", kvm_geterr(kd));					\
} while (/* CONSTCOND */0)

/*
 * Dereference the namelist pointer `v' and fill in the local copy
 * 'p' which is of size 's'.
 */
#define	deref_nl(v, p, s) do {						\
	deref_kptr((void *)namelist[(v)].n_value, (p), (s));		\
} while (/* CONSTCOND */0)

/* Missing from <sys/time.h> */
#define	timerset(tvp, uvp) do {						\
	((uvp)->tv_sec = (tvp)->tv_sec);				\
	((uvp)->tv_usec = (tvp)->tv_usec);				\
} while (/* CONSTCOND */0)

static void deref_kptr(void *, void *, size_t);

/*
 * Take the delta between the present values and the last recorded
 * values, storing the present values in the 'last' structure, and
 * the delta values in the 'cur' structure.
 */
void
dkswap(void)
{
	double etime;
	u_int64_t tmp;
	int	i, state;

#define	SWAP(fld) do {							\
	tmp = cur.fld;							\
	cur.fld -= last.fld;						\
	last.fld = tmp;							\
} while (/* CONSTCOND */0)

	for (i = 0; i < dk_ndrive; i++) {
		struct timeval	tmp_timer;

		if (!cur.dk_select[i])
			continue;

		/* Delta Values. */
		SWAP(dk_rxfer[i]);
		SWAP(dk_wxfer[i]);
		SWAP(dk_seek[i]);
		SWAP(dk_rbytes[i]);
		SWAP(dk_wbytes[i]);

		/* Delta Time. */
		timerclear(&tmp_timer);
		timerset(&(cur.dk_time[i]), &tmp_timer);
		timersub(&tmp_timer, &(last.dk_time[i]), &(cur.dk_time[i]));
		timerclear(&(last.dk_time[i]));
		timerset(&tmp_timer, &(last.dk_time[i]));
	}
	for (i = 0; i < CPUSTATES; i++)
		SWAP(cp_time[i]);
	SWAP(tk_nin);
	SWAP(tk_nout);

	etime = 0;
	for (state = 0; state < CPUSTATES; ++state) {
		etime += cur.cp_time[state];
	}
	if (etime == 0)
		etime = 1;
	etime /= hz;
	etime /= cur.cp_ncpu;

	cur.cp_etime = etime;

#undef SWAP
}

/*
 * Read the disk statistics for each disk in the disk list.
 * Also collect statistics for tty i/o and CPU ticks.
 */
void
dkreadstats(void)
{
	struct disk	cur_disk, *p;
	size_t		size;
	int		mib[3];
	int		i;

	p = dk_drivehead;

	if (memf == NULL) {
		mib[0] = CTL_HW;
		mib[1] = HW_DISKSTATS;
		mib[2] = sizeof(struct disk_sysctl);

		size = dk_ndrive * sizeof(struct disk_sysctl);
		if (sysctl(mib, 3, dk_drives, &size, NULL, 0) < 0)
			err(1, "sysctl hw.diskstats failed");
		for (i = 0; i < dk_ndrive; i++) {
			cur.dk_rxfer[i] = dk_drives[i].dk_rxfer;
			cur.dk_wxfer[i] = dk_drives[i].dk_wxfer;
			cur.dk_seek[i] = dk_drives[i].dk_seek;
			cur.dk_rbytes[i] = dk_drives[i].dk_rbytes;
			cur.dk_wbytes[i] = dk_drives[i].dk_wbytes;
			cur.dk_time[i].tv_sec = dk_drives[i].dk_time_sec;
			cur.dk_time[i].tv_usec = dk_drives[i].dk_time_usec;
		}

		mib[0] = CTL_KERN;
		mib[1] = KERN_TKSTAT;
		mib[2] = KERN_TKSTAT_NIN;
		size = sizeof(cur.tk_nin);
		if (sysctl(mib, 3, &cur.tk_nin, &size, NULL, 0) < 0)
			cur.tk_nin = 0;

		mib[2] = KERN_TKSTAT_NOUT;
		size = sizeof(cur.tk_nout);
		if (sysctl(mib, 3, &cur.tk_nout, &size, NULL, 0) < 0)
			cur.tk_nout = 0;
	} else {
		for (i = 0; i < dk_ndrive; i++) {
			deref_kptr(p, &cur_disk, sizeof(cur_disk));
			cur.dk_rxfer[i] = cur_disk.dk_rxfer;
			cur.dk_wxfer[i] = cur_disk.dk_wxfer;
			cur.dk_seek[i] = cur_disk.dk_seek;
			cur.dk_rbytes[i] = cur_disk.dk_rbytes;
			cur.dk_wbytes[i] = cur_disk.dk_wbytes;
			timerset(&(cur_disk.dk_time), &(cur.dk_time[i]));
			p = cur_disk.dk_link.tqe_next;
		}

		deref_nl(X_TK_NIN, &cur.tk_nin, sizeof(cur.tk_nin));
		deref_nl(X_TK_NOUT, &cur.tk_nout, sizeof(cur.tk_nout));
	}

	/*
	 * XXX Need to locate the `correct' CPU when looking for this
	 * XXX in crash dumps.  Just don't report it for now, in that
	 * XXX case.
	 */
	size = sizeof(cur.cp_time);
	memset(cur.cp_time, 0, size);
	if (memf == NULL) {
		mib[0] = CTL_KERN;
		mib[1] = KERN_CP_TIME;
		if (sysctl(mib, 2, cur.cp_time, &size, NULL, 0) < 0)
			memset(cur.cp_time, 0, sizeof(cur.cp_time));
	}
}

/*
 * Perform all of the initialization and memory allocation needed to
 * track disk statistics.
 */
int
dkinit(int select)
{
	struct disklist_head disk_head;
	struct disk	cur_disk, *p;
	struct clockinfo clockinfo;
	char		errbuf[_POSIX2_LINE_MAX];
	size_t		size;
	static int	once = 0;
	int		i, mib[3];

	if (once)
		return (1);

	if (memf == NULL) {
		mib[0] = CTL_HW;
		mib[1] = HW_NCPU;
		size = sizeof(cur.cp_ncpu);
		if (sysctl(mib, 2, &cur.cp_ncpu, &size, NULL, 0) == -1)
			err(1, "sysctl hw.ncpu failed");

		mib[0] = CTL_KERN;
		mib[1] = KERN_CLOCKRATE;
		size = sizeof(clockinfo);
		if (sysctl(mib, 2, &clockinfo, &size, NULL, 0) == -1)
			err(1, "sysctl kern.clockrate failed");
		hz = clockinfo.stathz;
		if (!hz)
			hz = clockinfo.hz;

		mib[0] = CTL_HW;
		mib[1] = HW_DISKSTATS;
		mib[2] = sizeof(struct disk_sysctl);
		if (sysctl(mib, 3, NULL, &size, NULL, 0) == -1)
			err(1, "sysctl hw.diskstats failed");
		dk_ndrive = size / sizeof(struct disk_sysctl);

		if (size == 0) {
			warnx("No drives attached.");
		} else {
			dk_drives = (struct disk_sysctl *)malloc(size);
			if (dk_drives == NULL)
				errx(1, "Memory allocation failure.");
		}
	} else {
		/* Open the kernel. */
		if ((kd = kvm_openfiles(nlistf, memf, NULL, O_RDONLY,
		    errbuf)) == NULL)
			errx(1, "kvm_openfiles: %s", errbuf);

		/* Obtain the namelist symbols from the kernel. */
		if (kvm_nlist(kd, namelist))
			KVM_ERROR("kvm_nlist failed to read symbols.");

		/* Get the number of attached drives. */
		deref_nl(X_DISK_COUNT, &dk_ndrive, sizeof(dk_ndrive));

		if (dk_ndrive < 0)
			errx(1, "invalid _disk_count %d.", dk_ndrive);
		else if (dk_ndrive == 0) {
			warnx("No drives attached.");
		} else {
			/* Get a pointer to the first disk. */
			deref_nl(X_DISKLIST, &disk_head, sizeof(disk_head));
			dk_drivehead = disk_head.tqh_first;
		}

		/* Get ticks per second. */
		deref_nl(X_STATHZ, &hz, sizeof(hz));
		if (!hz)
			deref_nl(X_HZ, &hz, sizeof(hz));
	}

	/* Allocate space for the statistics. */
	cur.dk_time = calloc(dk_ndrive, sizeof(struct timeval));
	cur.dk_rxfer = calloc(dk_ndrive, sizeof(u_int64_t));
	cur.dk_wxfer = calloc(dk_ndrive, sizeof(u_int64_t));
	cur.dk_seek = calloc(dk_ndrive, sizeof(u_int64_t));
	cur.dk_rbytes = calloc(dk_ndrive, sizeof(u_int64_t));
	cur.dk_wbytes = calloc(dk_ndrive, sizeof(u_int64_t));
	last.dk_time = calloc(dk_ndrive, sizeof(struct timeval));
	last.dk_rxfer = calloc(dk_ndrive, sizeof(u_int64_t));
	last.dk_wxfer = calloc(dk_ndrive, sizeof(u_int64_t));
	last.dk_seek = calloc(dk_ndrive, sizeof(u_int64_t));
	last.dk_rbytes = calloc(dk_ndrive, sizeof(u_int64_t));
	last.dk_wbytes = calloc(dk_ndrive, sizeof(u_int64_t));
	cur.dk_select = calloc(dk_ndrive, sizeof(int));
	cur.dk_name = calloc(dk_ndrive, sizeof(char *));

	if (cur.dk_time == NULL || cur.dk_rxfer == NULL ||
	    cur.dk_wxfer == NULL || cur.dk_seek == NULL ||
	    cur.dk_rbytes == NULL || cur.dk_wbytes == NULL ||
	    last.dk_time == NULL || last.dk_rxfer == NULL ||
	    last.dk_wxfer == NULL || last.dk_seek == NULL ||
	    last.dk_rbytes == NULL || last.dk_wbytes == NULL ||
	    cur.dk_select == NULL || cur.dk_name == NULL)
		errx(1, "Memory allocation failure.");

	/* Set up the compatibility interfaces. */
	dk_select = cur.dk_select;
	dr_name = cur.dk_name;

	/* Read the disk names and set intial selection. */
	if (memf == NULL) {
		mib[0] = CTL_HW;		/* Should be still set from */
		mib[1] = HW_DISKSTATS;		/* ... above, but be safe... */
		mib[2] = sizeof(struct disk_sysctl);
		if (sysctl(mib, 3, dk_drives, &size, NULL, 0) == -1)
			err(1, "sysctl hw.diskstats failed");
		for (i = 0; i < dk_ndrive; i++) {
			cur.dk_name[i] = dk_drives[i].dk_name;
			cur.dk_select[i] = select;
		}
	} else {
		p = dk_drivehead;
		for (i = 0; i < dk_ndrive; i++) {
			char	buf[10];
			deref_kptr(p, &cur_disk, sizeof(cur_disk));
			deref_kptr(cur_disk.dk_name, buf, sizeof(buf));
			cur.dk_name[i] = strdup(buf);
			if (!cur.dk_name[i])
				err(1, "strdup");
			cur.dk_select[i] = select;

			p = cur_disk.dk_link.tqe_next;
		}
	}

	/* Never do this initialization again. */
	once = 1;
	return (1);
}

/*
 * Dereference the kernel pointer `kptr' and fill in the local copy
 * pointed to by `ptr'.  The storage space must be pre-allocated,
 * and the size of the copy passed in `len'.
 */
static void
deref_kptr(void *kptr, void *ptr, size_t len)
{
	char buf[128];

	if (kvm_read(kd, (u_long)kptr, (char *)ptr, len) != len) {
		memset(buf, 0, sizeof(buf));
		snprintf(buf, sizeof buf, "can't dereference kptr 0x%lx",
		    (u_long)kptr);
		KVM_ERROR(buf);
	}
}