/*      $NetBSD: drvstats.c,v 1.14 2021/11/27 22:16:42 rillig 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/iostat.h>

#include <err.h>
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "drvstats.h"

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

extern int      hz;

/* sysctl hw.drivestats buffer. */
static struct io_sysctl *drives = NULL;

/* Backward compatibility references. */
size_t          ndrive = 0;
int             *drv_select;
char            **dr_name;

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

/*
 * 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
drvswap(void)
{
        u_int64_t tmp;
        size_t  i;

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

#define DELTA(x) do {                                                   \
                timerclear(&tmp_timer);                                 \
                timerset(&(cur.x), &tmp_timer);                         \
                timersub(&tmp_timer, &(last.x), &(cur.x));              \
                timerclear(&(last.x));                                  \
                timerset(&tmp_timer, &(last.x));                        \
} while (0)

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

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

                /*
                 * When a drive is replaced with one of the same
                 * name, the previous statistics are invalid. Try
                 * to detect this by validating counters and timestamp
                 */
                if ((cur.rxfer[i] == 0 && cur.wxfer[i] == 0)
                    || cur.rxfer[i] - last.rxfer[i] > INT64_MAX
                    || cur.wxfer[i] - last.wxfer[i] > INT64_MAX
                    || cur.seek[i] - last.seek[i] > INT64_MAX
                    || (cur.timestamp[i].tv_sec == 0 &&
                        cur.timestamp[i].tv_usec == 0)) {

                        last.rxfer[i] = cur.rxfer[i];
                        last.wxfer[i] = cur.wxfer[i];
                        last.seek[i] = cur.seek[i];
                        last.rbytes[i] = cur.rbytes[i];
                        last.wbytes[i] = cur.wbytes[i];

                        timerclear(&last.wait[i]);
                        timerclear(&last.time[i]);
                        timerclear(&last.waitsum[i]);
                        timerclear(&last.busysum[i]);
                        timerclear(&last.timestamp[i]);
                }

                /* Delta Values. */
                SWAP(rxfer[i]);
                SWAP(wxfer[i]);
                SWAP(seek[i]);
                SWAP(rbytes[i]);
                SWAP(wbytes[i]);

                DELTA(wait[i]);
                DELTA(time[i]);
                DELTA(waitsum[i]);
                DELTA(busysum[i]);
                DELTA(timestamp[i]);
        }
}

void
tkswap(void)
{
        u_int64_t tmp;

        SWAP(tk_nin);
        SWAP(tk_nout);
}

void
cpuswap(void)
{
        double etime;
        u_int64_t tmp;
        int     i, state;

        for (i = 0; i < CPUSTATES; i++)
                SWAP(cp_time[i]);

        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 DELTA
#undef SWAP

/*
 * Read the drive statistics for each drive in the drive list.
 * Also collect statistics for tty i/o and CPU ticks.
 */
void
drvreadstats(void)
{
        size_t          size, i, j, count;
        int             mib[3];

        mib[0] = CTL_HW;
        mib[1] = HW_IOSTATS;
        mib[2] = sizeof(struct io_sysctl);

        size = ndrive * sizeof(struct io_sysctl);
        if (sysctl(mib, 3, drives, &size, NULL, 0) < 0)
                err(1, "sysctl hw.iostats failed");
        /* recalculate array length */
        count = size / sizeof(struct io_sysctl);

#define COPYF(x,k,l) cur.x[k] = drives[l].x
#define COPYT(x,k,l) do {                                               \
                cur.x[k].tv_sec = drives[l].x##_sec;                    \
                cur.x[k].tv_usec = drives[l].x##_usec;                  \
} while (0)

        for (i = 0, j = 0; i < ndrive && j < count; i++) {

                /*
                 * skip removed entries
                 *
                 * we cannot detect entries replaced with
                 * devices of the same name (e.g. unplug/replug).
                 */
                if (strcmp(cur.name[i], drives[j].name)) {
                        cur.select[i] = 0;
                        continue;
                }

                COPYF(rxfer, i, j);
                COPYF(wxfer, i, j);
                COPYF(seek, i, j);
                COPYF(rbytes, i, j);
                COPYF(wbytes, i, j);

                COPYT(wait, i, j);
                COPYT(time, i, j);
                COPYT(waitsum, i, j);
                COPYT(busysum, i, j);
                COPYT(timestamp, i, j);

                ++j;
        }

        /* shrink table to new size */
        ndrive = j;

        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;

        size = sizeof(cur.cp_time);
        (void)memset(cur.cp_time, 0, size);
        mib[0] = CTL_KERN;
        mib[1] = KERN_CP_TIME;
        if (sysctl(mib, 2, cur.cp_time, &size, NULL, 0) < 0)
                (void)memset(cur.cp_time, 0, sizeof(cur.cp_time));
}
#undef COPYT
#undef COPYF

/*
 * Read collect statistics for tty i/o.
 */

void
tkreadstats(void)
{
        size_t          size;
        int             mib[3];

        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;
}

/*
 * Read collect statistics for CPU ticks.
 */

void
cpureadstats(void)
{
        size_t          size;
        int             mib[2];

        size = sizeof(cur.cp_time);
        (void)memset(cur.cp_time, 0, size);
        mib[0] = CTL_KERN;
        mib[1] = KERN_CP_TIME;
        if (sysctl(mib, 2, cur.cp_time, &size, NULL, 0) < 0)
                (void)memset(cur.cp_time, 0, sizeof(cur.cp_time));
}

/*
 * Perform all of the initialization and memory allocation needed to
 * track drive statistics.
 */
int
drvinit(int selected)
{
        struct clockinfo clockinfo;
        size_t          size, i;
        static int      once = 0;
        int             mib[3];

        if (once)
                return (1);

        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_IOSTATS;
        mib[2] = sizeof(struct io_sysctl);
        if (sysctl(mib, 3, NULL, &size, NULL, 0) == -1)
                err(1, "sysctl hw.drivestats failed");
        ndrive = size / sizeof(struct io_sysctl);

        if (size == 0) {
                warnx("No drives attached.");
        } else {
                drives = (struct io_sysctl *)malloc(size);
                if (drives == NULL)
                        errx(1, "Memory allocation failure.");
        }

        /* Allocate space for the statistics. */
        cur.time = calloc(ndrive, sizeof(struct timeval));
        cur.wait = calloc(ndrive, sizeof(struct timeval));
        cur.waitsum = calloc(ndrive, sizeof(struct timeval));
        cur.busysum = calloc(ndrive, sizeof(struct timeval));
        cur.timestamp = calloc(ndrive, sizeof(struct timeval));
        cur.rxfer = calloc(ndrive, sizeof(u_int64_t));
        cur.wxfer = calloc(ndrive, sizeof(u_int64_t));
        cur.seek = calloc(ndrive, sizeof(u_int64_t));
        cur.rbytes = calloc(ndrive, sizeof(u_int64_t));
        cur.wbytes = calloc(ndrive, sizeof(u_int64_t));
        cur.scale = calloc(ndrive, sizeof(int));
        last.time = calloc(ndrive, sizeof(struct timeval));
        last.wait = calloc(ndrive, sizeof(struct timeval));
        last.waitsum = calloc(ndrive, sizeof(struct timeval));
        last.busysum = calloc(ndrive, sizeof(struct timeval));
        last.timestamp = calloc(ndrive, sizeof(struct timeval));
        last.rxfer = calloc(ndrive, sizeof(u_int64_t));
        last.wxfer = calloc(ndrive, sizeof(u_int64_t));
        last.seek = calloc(ndrive, sizeof(u_int64_t));
        last.rbytes = calloc(ndrive, sizeof(u_int64_t));
        last.wbytes = calloc(ndrive, sizeof(u_int64_t));
        cur.select = calloc(ndrive, sizeof(int));
        cur.name = calloc(ndrive, sizeof(char *));

        if (cur.time == NULL || cur.wait == NULL ||
            cur.waitsum == NULL || cur.busysum == NULL ||
            cur.timestamp == NULL ||
            cur.rxfer == NULL || cur.wxfer == NULL ||
            cur.seek == NULL || cur.rbytes == NULL ||
            cur.wbytes == NULL ||
            last.time == NULL || last.wait == NULL ||
            last.waitsum == NULL || last.busysum == NULL ||
            last.timestamp == NULL ||
            last.rxfer == NULL || last.wxfer == NULL ||
            last.seek == NULL || last.rbytes == NULL ||
            last.wbytes == NULL ||
            cur.select == NULL || cur.name == NULL)
                errx(1, "Memory allocation failure.");

        /* Set up the compatibility interfaces. */
        drv_select = cur.select;
        dr_name = cur.name;

        /* Read the drive names and set initial selection. */
        mib[0] = CTL_HW;                /* Should be still set from */
        mib[1] = HW_IOSTATS;            /* ... above, but be safe... */
        mib[2] = sizeof(struct io_sysctl);
        if (sysctl(mib, 3, drives, &size, NULL, 0) == -1)
                err(1, "sysctl hw.iostats failed");
        /* Recalculate array length */
        ndrive = size / sizeof(struct io_sysctl);
        for (i = 0; i < ndrive; i++) {
                cur.name[i] = strndup(drives[i].name, sizeof(drives[i].name));
                if (cur.name[i] == NULL)
                        errx(1, "Memory allocation failure");
                cur.select[i] = selected;
        }

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