/*
 * 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 (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2012 by Delphix. All rights reserved.
 */

#include "statcommon.h"
#include "dsr.h"

#include <stdlib.h>
#include <unistd.h>
#include <strings.h>
#include <errno.h>
#include <limits.h>
#include <poll.h>

#define ARRAY_SIZE(a)   (sizeof (a) / sizeof (*a))

/*
 * The time we delay before retrying after an allocation
 * failure, in milliseconds
 */
#define RETRY_DELAY 200

static char *cpu_states[] = {
        "cpu_ticks_idle",
        "cpu_ticks_user",
        "cpu_ticks_kernel",
        "cpu_ticks_wait"
};

static kstat_t *
kstat_lookup_read(kstat_ctl_t *kc, char *module,
                int instance, char *name)
{
        kstat_t *ksp = kstat_lookup(kc, module, instance, name);
        if (ksp == NULL)
                return (NULL);
        if (kstat_read(kc, ksp, NULL) == -1)
                return (NULL);
        return (ksp);
}

/*
 * Note: the following helpers do not clean up on the failure case,
 * because it is left to the free_snapshot() in the acquire_snapshot()
 * failure path.
 */

static int
acquire_cpus(struct snapshot *ss, kstat_ctl_t *kc)
{
        size_t i;

        ss->s_nr_cpus = sysconf(_SC_CPUID_MAX) + 1;
        ss->s_cpus = calloc(ss->s_nr_cpus, sizeof (struct cpu_snapshot));
        if (ss->s_cpus == NULL)
                goto out;

        for (i = 0; i < ss->s_nr_cpus; i++) {
                kstat_t *ksp;

                ss->s_cpus[i].cs_id = ID_NO_CPU;
                ss->s_cpus[i].cs_state = p_online(i, P_STATUS);
                /* If no valid CPU is present, move on to the next one */
                if (ss->s_cpus[i].cs_state == -1)
                        continue;
                ss->s_cpus[i].cs_id = i;

                if ((ksp = kstat_lookup_read(kc, "cpu_info", i, NULL)) == NULL)
                        goto out;

                (void) pset_assign(PS_QUERY, i, &ss->s_cpus[i].cs_pset_id);
                if (ss->s_cpus[i].cs_pset_id == PS_NONE)
                        ss->s_cpus[i].cs_pset_id = ID_NO_PSET;

                if (!CPU_ACTIVE(&ss->s_cpus[i]))
                        continue;

                if ((ksp = kstat_lookup_read(kc, "cpu", i, "vm")) == NULL)
                        goto out;

                if (kstat_copy(ksp, &ss->s_cpus[i].cs_vm))
                        goto out;

                if ((ksp = kstat_lookup_read(kc, "cpu", i, "sys")) == NULL)
                        goto out;

                if (kstat_copy(ksp, &ss->s_cpus[i].cs_sys))
                        goto out;
        }

        errno = 0;
out:
        return (errno);
}

static int
acquire_psets(struct snapshot *ss)
{
        psetid_t *pids = NULL;
        struct pset_snapshot *ps;
        size_t pids_nr;
        size_t i, j;

        /*
         * Careful in this code. We have to use pset_list
         * twice, but inbetween pids_nr can change at will.
         * We delay the setting of s_nr_psets until we have
         * the "final" value of pids_nr.
         */

        if (pset_list(NULL, &pids_nr) < 0)
                return (errno);

        if ((pids = calloc(pids_nr, sizeof (psetid_t))) == NULL)
                goto out;

        if (pset_list(pids, &pids_nr) < 0)
                goto out;

        ss->s_psets = calloc(pids_nr + 1, sizeof (struct pset_snapshot));
        if (ss->s_psets == NULL)
                goto out;
        ss->s_nr_psets = pids_nr + 1;

        /* CPUs not in any actual pset */
        ps = &ss->s_psets[0];
        ps->ps_id = 0;
        ps->ps_cpus = calloc(ss->s_nr_cpus, sizeof (struct cpu_snapshot *));
        if (ps->ps_cpus == NULL)
                goto out;

        /* CPUs in a a pset */
        for (i = 1; i < ss->s_nr_psets; i++) {
                ps = &ss->s_psets[i];

                ps->ps_id = pids[i - 1];
                ps->ps_cpus =
                    calloc(ss->s_nr_cpus, sizeof (struct cpu_snapshot *));
                if (ps->ps_cpus == NULL)
                        goto out;
        }

        for (i = 0; i < ss->s_nr_psets; i++) {
                ps = &ss->s_psets[i];

                for (j = 0; j < ss->s_nr_cpus; j++) {
                        if (!CPU_ACTIVE(&ss->s_cpus[j]))
                                continue;
                        if (ss->s_cpus[j].cs_pset_id != ps->ps_id)
                                continue;

                        ps->ps_cpus[ps->ps_nr_cpus++] = &ss->s_cpus[j];
                }
        }

        errno = 0;
out:
        free(pids);
        return (errno);
}

static int
acquire_intrs(struct snapshot *ss, kstat_ctl_t *kc)
{
        kstat_t *ksp;
        size_t i = 0;
        kstat_t *sys_misc;
        kstat_named_t *clock;

        /* clock interrupt */
        ss->s_nr_intrs = 1;

        for (ksp = kc->kc_chain; ksp; ksp = ksp->ks_next) {
                if (ksp->ks_type == KSTAT_TYPE_INTR)
                        ss->s_nr_intrs++;
        }

        ss->s_intrs = calloc(ss->s_nr_intrs, sizeof (struct intr_snapshot));
        if (ss->s_intrs == NULL)
                return (errno);

        sys_misc = kstat_lookup_read(kc, "unix", 0, "system_misc");
        if (sys_misc == NULL)
                goto out;

        clock = (kstat_named_t *)kstat_data_lookup(sys_misc, "clk_intr");
        if (clock == NULL)
                goto out;

        (void) strlcpy(ss->s_intrs[0].is_name, "clock", KSTAT_STRLEN);
        ss->s_intrs[0].is_total = clock->value.ui32;

        i = 1;

        for (ksp = kc->kc_chain; ksp; ksp = ksp->ks_next) {
                kstat_intr_t *ki;
                int j;

                if (ksp->ks_type != KSTAT_TYPE_INTR)
                        continue;
                if (kstat_read(kc, ksp, NULL) == -1)
                        goto out;

                ki = KSTAT_INTR_PTR(ksp);

                (void) strlcpy(ss->s_intrs[i].is_name, ksp->ks_name,
                    KSTAT_STRLEN);
                ss->s_intrs[i].is_total = 0;

                for (j = 0; j < KSTAT_NUM_INTRS; j++)
                        ss->s_intrs[i].is_total += ki->intrs[j];

                i++;
        }

        errno = 0;
out:
        return (errno);
}

int
acquire_sys(struct snapshot *ss, kstat_ctl_t *kc)
{
        size_t i;
        kstat_named_t *knp;
        kstat_t *ksp;

        if ((ksp = kstat_lookup(kc, "unix", 0, "sysinfo")) == NULL)
                return (errno);

        if (kstat_read(kc, ksp, &ss->s_sys.ss_sysinfo) == -1)
                return (errno);

        if ((ksp = kstat_lookup(kc, "unix", 0, "vminfo")) == NULL)
                return (errno);

        if (kstat_read(kc, ksp, &ss->s_sys.ss_vminfo) == -1)
                return (errno);

        if ((ksp = kstat_lookup(kc, "unix", 0, "dnlcstats")) == NULL)
                return (errno);

        if (kstat_read(kc, ksp, &ss->s_sys.ss_nc) == -1)
                return (errno);

        if ((ksp = kstat_lookup(kc, "unix", 0, "system_misc")) == NULL)
                return (errno);

        if (kstat_read(kc, ksp, NULL) == -1)
                return (errno);

        knp = (kstat_named_t *)kstat_data_lookup(ksp, "clk_intr");
        if (knp == NULL)
                return (errno);

        ss->s_sys.ss_ticks = knp->value.l;

        knp = (kstat_named_t *)kstat_data_lookup(ksp, "deficit");
        if (knp == NULL)
                return (errno);

        ss->s_sys.ss_deficit = knp->value.l;

        for (i = 0; i < ss->s_nr_cpus; i++) {
                if (!CPU_ACTIVE(&ss->s_cpus[i]))
                        continue;

                if (kstat_add(&ss->s_cpus[i].cs_sys, &ss->s_sys.ss_agg_sys))
                        return (errno);
                if (kstat_add(&ss->s_cpus[i].cs_vm, &ss->s_sys.ss_agg_vm))
                        return (errno);
                ss->s_nr_active_cpus++;
        }

        return (0);
}

struct snapshot *
acquire_snapshot(kstat_ctl_t *kc, int types, struct iodev_filter *iodev_filter)
{
        struct snapshot *ss = NULL;
        int err;

retry:
        err = 0;
        /* ensure any partial resources are freed on a retry */
        free_snapshot(ss);

        ss = safe_alloc(sizeof (struct snapshot));

        (void) memset(ss, 0, sizeof (struct snapshot));

        ss->s_types = types;

        /* wait for a possibly up-to-date chain */
        while (kstat_chain_update(kc) == -1) {
                if (errno == EAGAIN)
                        (void) poll(NULL, 0, RETRY_DELAY);
                else
                        fail(1, "kstat_chain_update failed");
        }

        if (!err && (types & SNAP_INTERRUPTS))
                err = acquire_intrs(ss, kc);

        if (!err && (types & (SNAP_CPUS | SNAP_SYSTEM | SNAP_PSETS)))
                err = acquire_cpus(ss, kc);

        if (!err && (types & SNAP_PSETS))
                err = acquire_psets(ss);

        if (!err && (types & (SNAP_IODEVS | SNAP_CONTROLLERS |
            SNAP_IOPATHS_LI | SNAP_IOPATHS_LTI)))
                err = acquire_iodevs(ss, kc, iodev_filter);

        if (!err && (types & SNAP_SYSTEM))
                err = acquire_sys(ss, kc);

        switch (err) {
                case 0:
                        break;
                case EAGAIN:
                        (void) poll(NULL, 0, RETRY_DELAY);
                /* a kstat disappeared from under us */
                /*FALLTHRU*/
                case ENXIO:
                case ENOENT:
                        goto retry;
                default:
                        fail(1, "acquiring snapshot failed");
        }

        return (ss);
}

void
free_snapshot(struct snapshot *ss)
{
        size_t i;

        if (ss == NULL)
                return;

        while (ss->s_iodevs) {
                struct iodev_snapshot *tmp = ss->s_iodevs;
                ss->s_iodevs = ss->s_iodevs->is_next;
                free_iodev(tmp);
        }

        if (ss->s_cpus) {
                for (i = 0; i < ss->s_nr_cpus; i++) {
                        free(ss->s_cpus[i].cs_vm.ks_data);
                        free(ss->s_cpus[i].cs_sys.ks_data);
                }
                free(ss->s_cpus);
        }

        if (ss->s_psets) {
                for (i = 0; i < ss->s_nr_psets; i++)
                        free(ss->s_psets[i].ps_cpus);
                free(ss->s_psets);
        }

        free(ss->s_sys.ss_agg_sys.ks_data);
        free(ss->s_sys.ss_agg_vm.ks_data);
        free(ss);
}

kstat_ctl_t *
open_kstat(void)
{
        kstat_ctl_t *kc;

        while ((kc = kstat_open()) == NULL) {
                if (errno == EAGAIN)
                        (void) poll(NULL, 0, RETRY_DELAY);
                else
                        fail(1, "kstat_open failed");
        }

        return (kc);
}

void *
safe_alloc(size_t size)
{
        void *ptr;

        while ((ptr = malloc(size)) == NULL) {
                if (errno == EAGAIN)
                        (void) poll(NULL, 0, RETRY_DELAY);
                else
                        fail(1, "malloc failed");
        }
        return (ptr);
}

char *
safe_strdup(char *str)
{
        char *ret;

        if (str == NULL)
                return (NULL);

        while ((ret = strdup(str)) == NULL) {
                if (errno == EAGAIN)
                        (void) poll(NULL, 0, RETRY_DELAY);
                else
                        fail(1, "malloc failed");
        }
        return (ret);
}

uint64_t
kstat_delta(kstat_t *old, kstat_t *new, char *name)
{
        kstat_named_t *knew = kstat_data_lookup(new, name);
        if (old && old->ks_data) {
                kstat_named_t *kold = kstat_data_lookup(old, name);
                return (knew->value.ui64 - kold->value.ui64);
        }
        return (knew->value.ui64);
}

int
kstat_copy(const kstat_t *src, kstat_t *dst)
{
        *dst = *src;

        if (src->ks_data != NULL) {
                if ((dst->ks_data = malloc(src->ks_data_size)) == NULL)
                        return (-1);
                bcopy(src->ks_data, dst->ks_data, src->ks_data_size);
        } else {
                dst->ks_data = NULL;
                dst->ks_data_size = 0;
        }
        return (0);
}

int
kstat_add(const kstat_t *src, kstat_t *dst)
{
        size_t i;
        kstat_named_t *from;
        kstat_named_t *to;

        if (dst->ks_data == NULL)
                return (kstat_copy(src, dst));

        from = src->ks_data;
        to = dst->ks_data;

        for (i = 0; i < src->ks_ndata; i++) {
                /* "addition" makes little sense for strings */
                if (from->data_type != KSTAT_DATA_CHAR &&
                    from->data_type != KSTAT_DATA_STRING)
                        (to)->value.ui64 += (from)->value.ui64;
                from++;
                to++;
        }

        return (0);
}

uint64_t
cpu_ticks_delta(kstat_t *old, kstat_t *new)
{
        uint64_t ticks = 0;
        size_t i;
        for (i = 0; i < ARRAY_SIZE(cpu_states); i++)
                ticks += kstat_delta(old, new, cpu_states[i]);
        return (ticks);
}

int
nr_active_cpus(struct snapshot *ss)
{
        size_t i;
        int count = 0;
        for (i = 0; i < ss->s_nr_cpus; i++) {
                if (CPU_ACTIVE(&ss->s_cpus[i]))
                        count++;
        }

        return (count);
}

/*
 * Return the number of ticks delta between two hrtime_t
 * values. Attempt to cater for various kinds of overflow
 * in hrtime_t - no matter how improbable.
 */
uint64_t
hrtime_delta(hrtime_t old, hrtime_t new)
{
        uint64_t del;

        if ((new >= old) && (old >= 0L))
                return (new - old);
        else {
                /*
                 * We've overflowed the positive portion of an
                 * hrtime_t.
                 */
                if (new < 0L) {
                        /*
                         * The new value is negative. Handle the
                         * case where the old value is positive or
                         * negative.
                         */
                        uint64_t n1;
                        uint64_t o1;

                        n1 = -new;
                        if (old > 0L)
                                return (n1 - old);
                        else {
                                o1 = -old;
                                del = n1 - o1;
                                return (del);
                        }
                } else {
                        /*
                         * Either we've just gone from being negative
                         * to positive *or* the last entry was positive
                         * and the new entry is also positive but *less*
                         * than the old entry. This implies we waited
                         * quite a few days on a very fast system between
                         * iostat displays.
                         */
                        if (old < 0L) {
                                uint64_t o2;

                                o2 = -old;
                                del = UINT64_MAX - o2;
                        } else {
                                del = UINT64_MAX - old;
                        }
                        del += new;
                        return (del);
                }
        }
}