/*      $NetBSD: subr_iostat.c,v 1.26 2024/05/04 13:33:18 mlelstv 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 1.26 2024/05/04 13:33:18 mlelstv Exp $");

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/iostat.h>
#include <sys/sysctl.h>
#include <sys/rwlock.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 (EPERM);
       if (namelen != 0)
               return (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 (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);
}

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