/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <unistd.h>                             /* sleep() */
#include <string.h>
#include <errno.h>
#include <syslog.h>
#include <thread.h>
#include <time.h>
#include <kstat.h>
#include <sys/sysinfo.h>
#include <sys/sysmacros.h>
#include "powerd.h"

/*
 * External Variables
 */
extern  pwr_info_t      *info;

/*
 * State Variables
 */
static  kstat_ctl_t     *kc;                    /* libkstat cookie */
static  int             ncpus;
static  kstat_t         **cpu_stats_list = NULL;
static  kstat_t         old_cpu_stats, new_cpu_stats;
static  hrtime_t        tty_snaptime;
static  kstat_t         *load_ave_ksp;
static  ulong_t         load_ave;
static  hrtime_t        last_load_ave_change;
static  kstat_t         *conskbd_ksp, *consms_ksp;
static  kstat_t         *nfs_client2_kstat, *nfs_client3_kstat;
static  kstat_t         *nfs_server2_kstat, *nfs_server3_kstat;
static  uint64_t        old_nfs_calls, new_nfs_calls;

typedef struct activity_data {
                struct  activity_data   *next;
                struct  activity_data   *prev;
                int                     activity_delta;
                hrtime_t                snaptime;
} activity_data_t;

#define NULLACTIVITY (activity_data_t *)0
static  activity_data_t *disk_act_start = NULLACTIVITY;
static  activity_data_t *disk_act_end = NULLACTIVITY;
static  activity_data_t *tty_act_start = NULLACTIVITY;
static  activity_data_t *tty_act_end = NULLACTIVITY;
static  activity_data_t *nfs_act_start = NULLACTIVITY;
static  activity_data_t *nfs_act_end = NULLACTIVITY;

struct diskinfo {
        struct diskinfo *next;
        kstat_t         *ks;
        kstat_io_t      new_kios, old_kios;
};

#define NULLDISK (struct diskinfo *)0
static  struct diskinfo zerodisk = { NULL, NULL };
static  struct diskinfo *firstdisk = NULLDISK;
static  struct diskinfo *lastdisk = NULLDISK;
static  struct diskinfo *snip = NULLDISK;

#define CPU_STAT(ksp, name)     (((kstat_named_t *)safe_kstat_data_lookup( \
                                    (ksp), (name)))->value.ui64)
#define DISK_DELTA(x)   (disk->new_kios.x - disk->old_kios.x)
#define CPU_DELTA(x)    (CPU_STAT(&new_cpu_stats, (x)) - \
                            CPU_STAT(&old_cpu_stats, (x)))
#define FSHIFT          8
#define FSCALE          (1<<FSHIFT)

/*
 * Local Functions
 */
static  void    init_all(void);
static  void    init_disks(void);
static  void    cpu_stats_init(void);
static  void    load_ave_init(void);
static  void    nfs_init(void);
static  void    conskbd_init(void);
static  void    consms_init(void);
static  int     diskinfo_load(void);
static  int     cpu_stats_load(void);
static  int     load_ave_load(void);
static  int     nfs_load(void);
static  void    fail(char *, ...);
static  void    safe_zalloc(void **, int, int);
static  void    *safe_kstat_data_lookup(kstat_t *, char *);
static  int     kscmp(kstat_t *, kstat_t *);
static  void    keep_activity_data(activity_data_t **, activity_data_t **,
                                        int *, int, hrtime_t);
static  int     check_activity(activity_data_t *, int, hrtime_t *, int);
static  void    kstat_copy(kstat_t *, kstat_t *, int);

void
sysstat_init()
{
        info->pd_ttychars_sum = 0;
        info->pd_loadaverage = 0;
        info->pd_diskreads_sum = 0;
        info->pd_nfsreqs_sum = 0;

        if ((kc = kstat_open()) == NULL) {
                fail("kstat_open(): can't open /dev/kstat");
        }
        init_all();
}

static void
init_all(void)
{
        char *msg = "kstat_read(): can't read kstat";

        init_disks();
        if (diskinfo_load() != 0) {
                fail(msg);
        }

        cpu_stats_init();
        if (cpu_stats_load() != 0) {
                fail(msg);
        }

        load_ave_init();
        last_load_ave_change = gethrtime();
        if (load_ave_load() != 0) {
                fail(msg);
        }

        nfs_init();
        if (nfs_load() != 0) {
                fail(msg);
        }
        conskbd_init();
        consms_init();
}

int
last_disk_activity(hrtime_t *hr_now, int threshold)
{
        return (check_activity(disk_act_start, info->pd_diskreads_sum, hr_now,
                        threshold));
}

int
last_tty_activity(hrtime_t *hr_now, int threshold)
{
        return (check_activity(tty_act_start, info->pd_ttychars_sum, hr_now,
                        threshold));
}

int
last_load_ave_activity(hrtime_t *hr_now)
{
        return ((*hr_now - last_load_ave_change) / NANOSEC);
}

int
last_nfs_activity(hrtime_t *hr_now, int threshold)
{
        return (check_activity(nfs_act_start, info->pd_nfsreqs_sum, hr_now,
                        threshold));
}

static void
init_disks(void)
{
        struct diskinfo *disk, *prevdisk, *comp;
        kstat_t         *ksp;

        disk = &zerodisk;

        /*
         * Patch the snip in the diskinfo list (see below)
         */
        if (snip) {
                lastdisk->next = snip;
        }

        for (ksp = kc->kc_chain; ksp; ksp = ksp->ks_next) {
                if (ksp->ks_type != KSTAT_TYPE_IO ||
                                strcmp(ksp->ks_class, "disk") != 0) {
                        continue;
                }
                prevdisk = disk;
                if (disk->next) {
                        disk = disk->next;
                } else {
                        safe_zalloc((void **)&disk->next,
                                sizeof (struct diskinfo), 0);
                        disk = disk->next;
                        disk->next = NULLDISK;
                }
                disk->ks = ksp;
                (void) memset((void *)&disk->new_kios, 0,
                        sizeof (kstat_io_t));
                disk->new_kios.wlastupdate = disk->ks->ks_crtime;
                disk->new_kios.rlastupdate = disk->ks->ks_crtime;

                /*
                 * Insertion sort on (ks_module, ks_instance, ks_name)
                 */
                comp = &zerodisk;
                while (kscmp(disk->ks, comp->next->ks) > 0) {
                        comp = comp->next;
                }
                if (prevdisk != comp) {
                        prevdisk->next = disk->next;
                        disk->next = comp->next;
                        comp->next = disk;
                        disk = prevdisk;
                }
        }
        /*
         * Put a snip in the linked list of diskinfos.  The idea:
         * If there was a state change such that now there are fewer
         * disks, we snip the list and retain the tail, rather than
         * freeing it.  At the next state change, we clip the tail back on.
         * This prevents a lot of malloc/free activity, and it's simpler.
         */
        lastdisk = disk;
        snip = disk->next;
        disk->next = NULLDISK;

        firstdisk = zerodisk.next;
}

static int
diskinfo_load(void)
{
        struct diskinfo *disk;

        for (disk = firstdisk; disk; disk = disk->next) {
                disk->old_kios = disk->new_kios;
                if (kstat_read(kc, disk->ks,
                                (void *)&disk->new_kios) == -1) {
                        return (1);
                }
        }

        return (0);
}

int
check_disks(hrtime_t *hr_now, int threshold)
{
        struct diskinfo *disk;
        int             delta = 0;
        hrtime_t        time = 0;

        while (kstat_chain_update(kc) || diskinfo_load()) {
                init_all();
        }
        for (disk = firstdisk; disk; disk = disk->next) {
                if (time == 0) {
                        time = disk->new_kios.wlastupdate;
                }
                delta += DISK_DELTA(reads);
                if (DISK_DELTA(reads) > 0) {
                        time = MAX(time, disk->new_kios.wlastupdate);
                }
        }
        keep_activity_data(&disk_act_start, &disk_act_end,
                        &info->pd_diskreads_sum, delta, time);
#ifdef DEBUG
        (void) printf("    Disk reads = %d\n", delta);
#endif
        return (check_activity(disk_act_start, info->pd_diskreads_sum, hr_now,
                        threshold));
}

static void
cpu_stats_init(void)
{
        kstat_t *ksp;

        ncpus = 0;
        for (ksp = kc->kc_chain; ksp; ksp = ksp->ks_next) {
                if (strcmp(ksp->ks_module, "cpu") == 0 &&
                    strcmp(ksp->ks_name, "sys") == 0)
                        ncpus++;
        }

        safe_zalloc((void **)&cpu_stats_list, ncpus * sizeof (*cpu_stats_list),
            1);

        ncpus = 0;
        for (ksp = kc->kc_chain; ksp; ksp = ksp->ks_next) {
                if (strcmp(ksp->ks_module, "cpu") == 0 &&
                    strcmp(ksp->ks_name, "sys") == 0 &&
                    kstat_read(kc, ksp, NULL) != -1)
                        cpu_stats_list[ncpus++] = ksp;
        }

        if (ncpus == 0)
                fail("can't find any cpu statistics");
}

static int
cpu_stats_load(void)
{
        int             i, j;
        kstat_named_t   *nkp, *tkp;

        tty_snaptime = 0;
        kstat_copy(&new_cpu_stats, &old_cpu_stats, 1);

        /*
         * Sum across all cpus
         */
        for (i = 0; i < ncpus; i++) {
                if (kstat_read(kc, cpu_stats_list[i], NULL) == -1)
                        return (1);

                if (i == 0) {
                        kstat_copy(cpu_stats_list[i], &new_cpu_stats, 1);
                        continue;
                } else {
                        /*
                         * Other CPUs' statistics are accumulated in
                         * new_cpu_stats, initialized at the first iteration of
                         * the loop.
                         */
                        nkp = (kstat_named_t *)new_cpu_stats.ks_data;
                        tkp = (kstat_named_t *)cpu_stats_list[i]->ks_data;
                        for (j = 0; j < cpu_stats_list[i]->ks_ndata; j++)
                                (nkp++)->value.ui64 += (tkp++)->value.ui64;
                        tty_snaptime = MAX(tty_snaptime,
                            cpu_stats_list[i]->ks_snaptime);
                }
        }

        return (0);
}

int
check_tty(hrtime_t *hr_now, int threshold)
{
        int     delta;

        while (kstat_chain_update(kc) || cpu_stats_load()) {
                init_all();
        }
        delta = CPU_DELTA("rawch") + CPU_DELTA("outch");
        keep_activity_data(&tty_act_start, &tty_act_end,
                        &info->pd_ttychars_sum, delta, tty_snaptime);
#ifdef DEBUG
        (void) printf("    Tty chars = %d\n", delta);
#endif
        return (check_activity(tty_act_start, info->pd_ttychars_sum, hr_now,
                        threshold));
}

static void
load_ave_init(void)
{
        if ((load_ave_ksp = kstat_lookup(kc, "unix", 0, "system_misc")) ==
                        NULL) {
                fail("kstat_lookup('unix', 0, 'system_misc') failed");
        }
}

static int
load_ave_load(void)
{
        if (kstat_read(kc, load_ave_ksp, NULL) == -1) {
                return (1);
        }
        load_ave = ((kstat_named_t *)safe_kstat_data_lookup(
                load_ave_ksp, "avenrun_1min"))->value.l;

        return (0);
}

int
check_load_ave(hrtime_t *hr_now, float threshold)
{
        while (kstat_chain_update(kc) || load_ave_load()) {
                init_all();
        }
        info->pd_loadaverage = (double)load_ave / FSCALE;
        if (info->pd_loadaverage > threshold) {
                last_load_ave_change = load_ave_ksp->ks_snaptime;
        }
#ifdef DEBUG
        (void) printf("    Load average = %f\n", ((double)load_ave / FSCALE));
#endif
        return ((*hr_now - last_load_ave_change) / NANOSEC);
}

static void
nfs_init(void)
{
        nfs_client2_kstat = kstat_lookup(kc, "nfs", 0, "rfsreqcnt_v2");
        nfs_client3_kstat = kstat_lookup(kc, "nfs", 0, "rfsreqcnt_v3");
        nfs_server2_kstat = kstat_lookup(kc, "nfs", 0, "rfsproccnt_v2");
        nfs_server3_kstat = kstat_lookup(kc, "nfs", 0, "rfsproccnt_v3");
}

static int
nfs_load(void)
{
        kstat_named_t   *kstat_ptr;
        int             index;
        uint64_t        total_calls = 0;
        uint64_t        getattr_calls = 0;
        uint64_t        null_calls = 0;
        uint64_t        access_calls = 0;

        if (!nfs_client2_kstat && !nfs_client3_kstat && !nfs_server2_kstat &&
                        !nfs_server3_kstat) {
                return (0);
        }

        /*
         * NFS client "getattr", NFS3 client "access", and NFS server "null"
         * requests are excluded from consideration.
         */
        if (nfs_client2_kstat) {
                if (kstat_read(kc, nfs_client2_kstat, NULL) == -1) {
                        return (1);
                }
                kstat_ptr = KSTAT_NAMED_PTR(nfs_client2_kstat);
                for (index = 0; index < nfs_client2_kstat->ks_ndata; index++) {
                        total_calls += kstat_ptr[index].value.ui64;
                }
                getattr_calls =
                        ((kstat_named_t *)safe_kstat_data_lookup(
                        nfs_client2_kstat, "getattr"))->value.ui64;
        }

        if (nfs_client3_kstat) {
                if (kstat_read(kc, nfs_client3_kstat, NULL) == -1) {
                        return (1);
                }
                kstat_ptr = KSTAT_NAMED_PTR(nfs_client3_kstat);
                for (index = 0; index < nfs_client3_kstat->ks_ndata; index++) {
                        total_calls += kstat_ptr[index].value.ui64;
                }
                getattr_calls +=
                        ((kstat_named_t *)safe_kstat_data_lookup(
                        nfs_client3_kstat, "getattr"))->value.ui64;
                access_calls =
                        ((kstat_named_t *)safe_kstat_data_lookup(
                        nfs_client3_kstat, "access"))->value.ui64;
        }

        if (nfs_server2_kstat) {
                if (kstat_read(kc, nfs_server2_kstat, NULL) == -1) {
                        return (1);
                }
                kstat_ptr = KSTAT_NAMED_PTR(nfs_server2_kstat);
                for (index = 0; index < nfs_server2_kstat->ks_ndata; index++) {
                        total_calls += kstat_ptr[index].value.ui64;
                }
                null_calls =
                        ((kstat_named_t *)safe_kstat_data_lookup(
                        nfs_server2_kstat, "null"))->value.ui64;
        }

        if (nfs_server3_kstat) {
                if (kstat_read(kc, nfs_server3_kstat, NULL) == -1) {
                        return (1);
                }
                kstat_ptr = KSTAT_NAMED_PTR(nfs_server3_kstat);
                for (index = 0; index < nfs_server3_kstat->ks_ndata; index++) {
                        total_calls += kstat_ptr[index].value.ui64;
                }
                null_calls +=
                        ((kstat_named_t *)safe_kstat_data_lookup(
                        nfs_server3_kstat, "null"))->value.ui64;
        }

        old_nfs_calls = new_nfs_calls;
        new_nfs_calls = total_calls -
                (getattr_calls + access_calls + null_calls);

        return (0);
}

int
check_nfs(hrtime_t *hr_now, int threshold)
{
        int             delta;
        hrtime_t        time = 0;

        while (kstat_chain_update(kc) || nfs_load()) {
                init_all();
        }

        if (!nfs_client2_kstat && !nfs_client3_kstat && !nfs_server2_kstat &&
                        !nfs_server3_kstat) {
                return (0);
        }

        if (nfs_client2_kstat) {
                time = MAX(time, nfs_client2_kstat->ks_snaptime);
        }
        if (nfs_client3_kstat) {
                time = MAX(time, nfs_client3_kstat->ks_snaptime);
        }
        if (nfs_server2_kstat) {
                time = MAX(time, nfs_server2_kstat->ks_snaptime);
        }
        if (nfs_server3_kstat) {
                time = MAX(time, nfs_server3_kstat->ks_snaptime);
        }
        delta = (int)(new_nfs_calls - old_nfs_calls);
        keep_activity_data(&nfs_act_start, &nfs_act_end,
                        &info->pd_nfsreqs_sum, delta, time);
#ifdef DEBUG
        (void) printf("    NFS requests = %d\n", delta);
#endif
        return (check_activity(nfs_act_start, info->pd_nfsreqs_sum, hr_now,
                        threshold));
}

static void
conskbd_init(void)
{
        conskbd_ksp = kstat_lookup(kc, "conskbd", 0, "activity");
}

/*
 * Return the number of seconds since the last keystroke on console keyboard.
 * Caller responsible for error reporting.
 */
long
conskbd_idle_time(void)
{
        void *p;

        if (conskbd_ksp == NULL || kstat_read(kc, conskbd_ksp, NULL) == -1 ||
            (p = kstat_data_lookup(conskbd_ksp, "idle_sec")) == NULL)
                return ((time_t)-1);

        return (((kstat_named_t *)p)->value.l);
}

static void
consms_init(void)
{
        consms_ksp = kstat_lookup(kc, "consms", 0, "activity");
}

/*
 * Return the number of seconds since the most recent action (movement or
 * click) of the console mouse.  Caller responsible for error reporting.
 */
long
consms_idle_time(void)
{
        void *p;

        if (consms_ksp == NULL || kstat_read(kc, consms_ksp, NULL) == -1 ||
            (p = kstat_data_lookup(consms_ksp, "idle_sec")) == NULL)
                return ((time_t)-1);

        return (((kstat_named_t *)p)->value.l);
}

static void
fail(char *fmt, ...)
{
        char new_fmt[256];
        const char *fmtptr = new_fmt;
        va_list args;
        size_t len;

        len = sizeof (new_fmt);
        va_start(args, fmt);
        if (snprintf(new_fmt, len, "powerd: %s", fmt) > len)
                syslog(LOG_ERR, "powerd: syslog message too large");
        else
                vsyslog(LOG_ERR, fmtptr, args);
        va_end(args);

        thr_exit((void *) 0);
}

static void
safe_zalloc(void **ptr, int size, int free_first)
{
        if (free_first && *ptr != NULL) {
                free(*ptr);
        }
        if ((*ptr = (void *) malloc(size)) == NULL) {
                fail("malloc failed");
        }
        (void) memset(*ptr, 0, size);
}

static void *
safe_kstat_data_lookup(kstat_t *ksp, char *name)
{
        void *fp = kstat_data_lookup(ksp, name);

        if (fp == NULL) {
                fail("kstat_data_lookup('%s', '%s') failed",
                        ksp->ks_name, name);
        }
        return (fp);
}

static int
kscmp(kstat_t *ks1, kstat_t *ks2)
{
        int cmp;

        cmp = strcmp(ks1->ks_module, ks2->ks_module);
        if (cmp != 0) {
                return (cmp);
        }
        cmp = ks1->ks_instance - ks2->ks_instance;
        if (cmp != 0) {
                return (cmp);
        }
        return (strcmp(ks1->ks_name, ks2->ks_name));
}

static void
keep_activity_data(activity_data_t **act_start, activity_data_t **act_end,
                        int *delta_sum, int delta, hrtime_t time)
{
        activity_data_t *node = NULLACTIVITY;
        hrtime_t        hr_now;
        int             idle_time = info->pd_idle_time * 60;

        /*
         * Add new nodes to the beginning of the list.
         */
        safe_zalloc((void **)&node, sizeof (activity_data_t), 0);
        node->activity_delta = delta;
        *delta_sum += delta;
        node->snaptime = time;
        node->next = *act_start;
        if (*act_start == NULLACTIVITY) {
                *act_end = node;
        } else {
                (*act_start)->prev = node;
        }
        *act_start = node;

        /*
         * Remove nodes that are time-stamped later than the idle time.
         */
        hr_now = gethrtime();
        node = *act_end;
        while ((int)((hr_now - node->snaptime) / NANOSEC) > idle_time &&
                        node->prev != NULLACTIVITY) {
                *delta_sum -= node->activity_delta;
                *act_end = node->prev;
                (*act_end)->next = NULLACTIVITY;
                free(node);
                node = *act_end;
        }
}

static int
check_activity(activity_data_t *act_start, int delta_sum, hrtime_t *time,
                        int thold)
{
        activity_data_t *node;
        int             sum = 0;
        int             idle_time = info->pd_idle_time * 60;

        /*
         * No need to walk the list if the sum of the deltas are not greater
         * than the threshold value.
         */
        if (delta_sum <= thold) {
                return (idle_time);
        }

        /*
         * Walk through the list and add up the activity deltas.  When the
         * sum is greater than the threshold value, difference of current
         * time and the snaptime of that node will give us the idle time.
         */
        node = act_start;
        while (node->next != NULLACTIVITY) {
                sum += node->activity_delta;
                if (sum > thold) {
                        return ((*time - node->snaptime) / NANOSEC);
                }
                node = node->next;
        }
        sum += node->activity_delta;
        if (sum > thold) {
                return ((*time - node->snaptime) / NANOSEC);
        }

        return (idle_time);
}

static void
kstat_copy(kstat_t *src, kstat_t *dst, int fr)
{
        if (fr)
                free(dst->ks_data);

        *dst = *src;
        if (src->ks_data != NULL) {
                safe_zalloc(&dst->ks_data, src->ks_data_size, 0);
                (void) memcpy(dst->ks_data, src->ks_data, src->ks_data_size);
        } else {
                dst->ks_data = NULL;
                dst->ks_data_size = 0;
        }
}