/*      $NetBSD: subr_iostat.c,v 1.28 2026/01/04 03:18:46 riastradh Exp $       */
/*      NetBSD: subr_disk.c,v 1.69 2005/05/29 22:24:15 christos Exp     */

/*-
 * Copyright (c) 1996, 1997, 1999, 2000, 2009 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
 * NASA Ames Research Center.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``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 FOUNDATION OR CONTRIBUTORS
 * 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.
 */

/*
 * Copyright (c) 1982, 1986, 1988, 1993
 *      The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * 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. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
 *
 *      @(#)ufs_disksubr.c      8.5 (Berkeley) 1/21/94
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_iostat.c,v 1.28 2026/01/04 03:18:46 riastradh Exp $");

#include <sys/param.h>
#include <sys/types.h>

#include <sys/iostat.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/rwlock.h>
#include <sys/sdt.h>
#include <sys/sysctl.h>

/*
 * Function prototypes for sysctl nodes
 */
static int      sysctl_hw_disknames(SYSCTLFN_PROTO);
static int      sysctl_hw_iostatnames(SYSCTLFN_PROTO);
static int      sysctl_hw_iostats(SYSCTLFN_PROTO);

static int
iostati_getnames(int disk_only, char *oldp, size_t *oldlenp, const void *newp,
                u_int namelen);

/*
 * A global list of all drives attached to the system.  May grow or
 * shrink over time.
 */
struct iostatlist_head iostatlist = TAILQ_HEAD_INITIALIZER(iostatlist);
int iostat_count;               /* number of drives in global drivelist */
krwlock_t iostatlist_lock;

static void sysctl_io_stats_setup(struct sysctllog **);

/*
 * Initialise the iostat subsystem.
 */
void
iostat_init(void)
{

        rw_init(&iostatlist_lock);
        sysctl_io_stats_setup(NULL);
}

/*
 * Searches the iostatlist for the iostat corresponding to the
 * name provided.
 */
struct io_stats *
iostat_find(const char *name)
{
        struct io_stats *iostatp;

        KASSERT(name != NULL);

        rw_enter(&iostatlist_lock, RW_READER);
        TAILQ_FOREACH(iostatp, &iostatlist, io_link) {
                if (strcmp(iostatp->io_name, name) == 0) {
                        break;
                }
        }
        rw_exit(&iostatlist_lock);

        return iostatp;
}

/*
 * Allocate and initialise memory for the i/o statistics.
 */
struct io_stats *
iostat_alloc(int32_t type, void *parent, const char *name)
{
        struct io_stats *stats;

        stats = kmem_zalloc(sizeof(*stats), KM_SLEEP);
        stats->io_type = type;
        stats->io_parent = parent;
        (void)strlcpy(stats->io_name, name, sizeof(stats->io_name));

        /*
         * Set the attached timestamp.
         */
        getmicrouptime(&stats->io_attachtime);

        /*
         * Link into the drivelist.
         */
        rw_enter(&iostatlist_lock, RW_WRITER);
        TAILQ_INSERT_TAIL(&iostatlist, stats, io_link);
        iostat_count++;
        rw_exit(&iostatlist_lock);

        return stats;
}

/*
 * Remove i/o from stats collection.
 */
void
iostat_free(struct io_stats *stats)
{

        /*
         * Remove from the iostat list.
         */
        if (iostat_count == 0)
                panic("iostat_free: iostat_count == 0");
        rw_enter(&iostatlist_lock, RW_WRITER);
        TAILQ_REMOVE(&iostatlist, stats, io_link);
        iostat_count--;
        rw_exit(&iostatlist_lock);
        kmem_free(stats, sizeof(*stats));
}

/*
 * Rename i/o stats.
 */
void
iostat_rename(struct io_stats *stats, const char *name)
{

        rw_enter(&iostatlist_lock, RW_WRITER);
        (void)strlcpy(stats->io_name, name, sizeof(stats->io_name));
        rw_exit(&iostatlist_lock);
}

/*
 * multiply timeval by unsigned integer and add to result
 */
static void
timermac(struct timeval *a, uint64_t count, struct timeval *res)
{
        struct timeval part = *a;

        while (count) {
                if (count & 1)
                        timeradd(res, &part, res);
                timeradd(&part, &part, &part);
                count >>= 1;
        }
}

/*
 * Increment the iostat wait counter.
 * Accumulate wait time and timesum.
 *
 * Wait time is spent in the device bufq.
 */
void
iostat_wait(struct io_stats *stats)
{
        struct timeval dv_time, diff_time;
        int32_t count;

        KASSERT(stats->io_wait >= 0);

        getmicrouptime(&dv_time);

        timersub(&dv_time, &stats->io_waitstamp, &diff_time);
        count = stats->io_wait++;
        if (count != 0) {
                timermac(&diff_time, count, &stats->io_waitsum);
                timeradd(&stats->io_waittime, &diff_time, &stats->io_waittime);
        }
        stats->io_waitstamp = dv_time;
}

/*
 * Decrement the iostat wait counter.
 * Increment the iostat busy counter.
 * Accumulate wait and busy times and timesums.
 *
 * Busy time is spent being processed by the device.
 *
 * Old devices do not yet measure wait time, so skip
 * processing it if the counter is still zero.
 */
void
iostat_busy(struct io_stats *stats)
{
        struct timeval dv_time, diff_time;
        int32_t count;

        KASSERT(stats->io_wait >= 0); /* > 0 when iostat_wait is used */
        KASSERT(stats->io_busy >= 0);

        getmicrouptime(&dv_time);

        timersub(&dv_time, &stats->io_waitstamp, &diff_time);
        if (stats->io_wait != 0) {
                count = stats->io_wait--;
                timermac(&diff_time, count, &stats->io_waitsum);
                timeradd(&stats->io_waittime, &diff_time, &stats->io_waittime);
        }
        stats->io_waitstamp = dv_time;

        timersub(&dv_time, &stats->io_busystamp, &diff_time);
        count = stats->io_busy++;
        if (count != 0) {
                timermac(&diff_time, count, &stats->io_busysum);
                timeradd(&stats->io_busytime, &diff_time, &stats->io_busytime);
        }
        stats->io_busystamp = dv_time;
}

/*
 * Decrement the iostat busy counter, increment the byte count.
 * Accumulate busy time and timesum.
 */
void
iostat_unbusy(struct io_stats *stats, long bcount, int read)
{
        struct timeval dv_time, diff_time;
        int32_t count;

        KASSERT(stats->io_busy > 0);

        getmicrouptime(&dv_time);
        stats->io_timestamp = dv_time;

        /* any op */
        timersub(&dv_time, &stats->io_busystamp, &diff_time);
        count = stats->io_busy--;
        timermac(&diff_time, count, &stats->io_busysum);
        timeradd(&stats->io_busytime, &diff_time, &stats->io_busytime);
        stats->io_busystamp = dv_time;

        if (bcount > 0) {
                if (read) {
                        stats->io_rbytes += bcount;
                        stats->io_rxfer++;
                } else {
                        stats->io_wbytes += bcount;
                        stats->io_wxfer++;
                }
        }
}

/*
 * Return non-zero if a device has an I/O request in flight.
 */
bool
iostat_isbusy(struct io_stats *stats)
{

        return stats->io_busy != 0;
}

/*
 * Increment the seek counter.  This does look almost redundant but it
 * abstracts the stats gathering.
 */
void
iostat_seek(struct io_stats *stats)
{

        stats->io_seek++;
}

static int
sysctl_hw_disknames(SYSCTLFN_ARGS)
{

        return iostati_getnames(1, oldp, oldlenp, newp, namelen);
}

static int
sysctl_hw_iostatnames(SYSCTLFN_ARGS)
{

        return iostati_getnames(0, oldp, oldlenp, newp, namelen);
}

static int
iostati_getnames(int disk_only, char *oldp, size_t *oldlenp, const void *newp,
                 u_int namelen)
{
        char bf[IOSTATNAMELEN + 1];
        char *where = oldp;
        struct io_stats *stats;
        size_t needed, left, slen;
        int error, first;

        if (newp != NULL)
                return SET_ERROR(EPERM);
        if (namelen != 0)
                return SET_ERROR(EINVAL);

        first = 1;
        error = 0;
        needed = 0;
        left = *oldlenp;

        rw_enter(&iostatlist_lock, RW_READER);
        for (stats = TAILQ_FIRST(&iostatlist); stats != NULL;
            stats = TAILQ_NEXT(stats, io_link)) {
                if ((disk_only == 1) && (stats->io_type != IOSTAT_DISK))
                        continue;

                if (where == NULL)
                        needed += strlen(stats->io_name) + 1;
                else {
                        memset(bf, 0, sizeof(bf));
                        if (first) {
                                strncpy(bf, stats->io_name, sizeof(bf));
                                /* account for trailing NUL byte */
                                needed += 1;
                                first = 0;
                        } else {
                                bf[0] = ' ';
                                strncpy(bf + 1, stats->io_name,
                                    sizeof(bf) - 1);
                        }
                        bf[IOSTATNAMELEN] = '\0';
                        slen = strlen(bf);
                        if (left < slen + 1)
                                break;
                        /* +1 to copy out the trailing NUL byte */
                        error = copyout(bf, where, slen + 1);
                        if (error)
                                break;
                        where += slen;
                        needed += slen;
                        left -= slen;
                }
        }
        rw_exit(&iostatlist_lock);
        *oldlenp = needed;
        return error;
}

static int
sysctl_hw_iostats(SYSCTLFN_ARGS)
{
        struct io_sysctl sdrive;
        struct io_stats *stats;
        char *where = oldp;
        size_t tocopy, left;
        int error;

        if (newp != NULL)
                return SET_ERROR(EPERM);

        /*
         * The original hw.diskstats call was broken and did not require
         * the userland to pass in its size of struct disk_sysctl.  This
         * was fixed after NetBSD 1.6 was released.
         */
        if (namelen == 0)
                tocopy = offsetof(struct io_sysctl, busy);
        else
                tocopy = name[0];

        if (where == NULL) {
                *oldlenp = iostat_count * tocopy;
                return 0;
        }

        error = 0;
        left = *oldlenp;
        memset(&sdrive, 0, sizeof(sdrive));
        *oldlenp = 0;

        rw_enter(&iostatlist_lock, RW_READER);
        TAILQ_FOREACH(stats, &iostatlist, io_link) {
                if (left < tocopy)
                        break;

                strncpy(sdrive.name, stats->io_name, sizeof(sdrive.name));
                sdrive.attachtime_sec = stats->io_attachtime.tv_sec;
                sdrive.attachtime_usec = stats->io_attachtime.tv_usec;
                sdrive.timestamp_sec = stats->io_busystamp.tv_sec;
                sdrive.timestamp_usec = stats->io_busystamp.tv_usec;

                sdrive.time_sec = stats->io_busytime.tv_sec;
                sdrive.time_usec = stats->io_busytime.tv_usec;

                sdrive.seek = stats->io_seek;

                sdrive.rxfer = stats->io_rxfer;
                sdrive.wxfer = stats->io_wxfer;
                sdrive.xfer = stats->io_rxfer + stats->io_wxfer;

                sdrive.rbytes = stats->io_rbytes;
                sdrive.wbytes = stats->io_wbytes;
                sdrive.bytes = stats->io_rbytes + stats->io_wbytes;

                sdrive.wait_sec = stats->io_waittime.tv_sec;
                sdrive.wait_usec = stats->io_waittime.tv_usec;

                sdrive.time_sec = stats->io_busytime.tv_sec;
                sdrive.time_usec = stats->io_busytime.tv_usec;

                sdrive.waitsum_sec = stats->io_waitsum.tv_sec;
                sdrive.waitsum_usec = stats->io_waitsum.tv_usec;

                sdrive.busysum_sec = stats->io_busysum.tv_sec;
                sdrive.busysum_usec = stats->io_busysum.tv_usec;

                sdrive.busy = stats->io_busy;

                error = copyout(&sdrive, where, uimin(tocopy, sizeof(sdrive)));
                if (error)
                        break;
                where += tocopy;
                *oldlenp += tocopy;
                left -= tocopy;
        }
        rw_exit(&iostatlist_lock);
        return error;
}

static void
sysctl_io_stats_setup(struct sysctllog **clog)
{

        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT,
                       CTLTYPE_STRING, "disknames",
                       SYSCTL_DESCR("List of disk drives present"),
                       sysctl_hw_disknames, 0, NULL, 0,
                       CTL_HW, HW_DISKNAMES, CTL_EOL);
        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT,
                       CTLTYPE_STRING, "iostatnames",
                       SYSCTL_DESCR("I/O stats are being collected for these"
                                    " devices"),
                       sysctl_hw_iostatnames, 0, NULL, 0,
                       CTL_HW, HW_IOSTATNAMES, CTL_EOL);
        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT,
                       CTLTYPE_STRUCT, "iostats",
                       SYSCTL_DESCR("Statistics on device I/O operations"),
                       sysctl_hw_iostats, 0, NULL, 0,
                       CTL_HW, HW_IOSTATS, CTL_EOL);
}