/*
 * Copyright (c) 2004-2007 Hyperic, Inc.
 * Copyright (c) 2009 SpringSource, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "sigar.h"
#include "sigar_private.h"
#include "sigar_util.h"
#include "sigar_os.h"

int sigar_get_kstats(sigar_t *sigar)
{
    kstat_ctl_t *kc = sigar->kc;
    unsigned int i, id, ncpu = sysconf(_SC_NPROCESSORS_CONF);
    int is_debug = SIGAR_LOG_IS_DEBUG(sigar);

    if (ncpu != sigar->ncpu) {
        if (!sigar->ks.lcpu) {
            /* init */
            sigar->ks.lcpu = ncpu;
            sigar->ks.cpu = malloc(sizeof(*(sigar->ks.cpu)) * ncpu);
            sigar->ks.cpu_info = malloc(sizeof(*(sigar->ks.cpu_info)) * ncpu);
            sigar->ks.cpuid = malloc(sizeof(*(sigar->ks.cpuid)) * ncpu);
        }
        else {
            sigar_log_printf(sigar, SIGAR_LOG_INFO,
                             "ncpu changed from %d to %d",
                             sigar->ncpu, ncpu);
            if (ncpu > sigar->ks.lcpu) {
                /* one or more cpus have been added */
                sigar->ks.cpu = realloc(sigar->ks.cpu,
                                        sizeof(*(sigar->ks.cpu)) * ncpu);
                sigar->ks.cpu_info = realloc(sigar->ks.cpu_info,
                                             sizeof(*(sigar->ks.cpu_info)) * ncpu);
                sigar->ks.cpuid = realloc(sigar->ks.cpuid,
                                          sizeof(*(sigar->ks.cpuid)) * ncpu);
                sigar->ks.lcpu = ncpu;
            }
            /* else or more cpus have been removed */
        }

        sigar->ncpu = ncpu;

        /* from man p_online:
         * ``Processor numbers are integers,
         *   greater than or equal to 0,
         *   and are defined by the hardware platform.
         *   Processor numbers are not necessarily contiguous,
         *   but "not too sparse."``
         * so we maintain our own mapping in ks.cpuid[]
         */

        /* lookup in order, which kstat chain may not be in */
        for (i=0, id=0; i<ncpu; id++) {
            kstat_t *cpu_info, *cpu_stat;

            if (!(cpu_info = kstat_lookup(kc, "cpu_info", id, NULL))) {
                continue;
            }

            if (!(cpu_stat = kstat_lookup(kc, "cpu_stat", id, NULL))) {
                /* XXX warn, faulted cpu? */
            }

            sigar->ks.cpu_info[i] = cpu_info;
            sigar->ks.cpu[i] = cpu_stat;
            sigar->ks.cpuid[i] = id;

            if (is_debug) {
                sigar_log_printf(sigar, SIGAR_LOG_DEBUG,
                                 "cpu %d id=%d", i, sigar->ks.cpuid[i]);
            }
            i++;
        }
    }
        
    sigar->ks.system   = kstat_lookup(kc, "unix", -1, "system_misc");
    sigar->ks.syspages = kstat_lookup(kc, "unix", -1, "system_pages");
    sigar->ks.mempages = kstat_lookup(kc, "bunyip", -1, "mempages");

    return SIGAR_OK;
}

SIGAR_INLINE kid_t sigar_kstat_update(sigar_t *sigar)
{
    kid_t id = kstat_chain_update(sigar->kc);

    switch (id) {
      case -1:
        sigar_log_printf(sigar, SIGAR_LOG_ERROR,
                         "kstat_chain_update error: %s",
                         sigar_strerror(sigar, errno));
        break;
      case 0:
        /* up-to-date */
        break;
      default:
        sigar_get_kstats(sigar);
        sigar_log(sigar, SIGAR_LOG_DEBUG,
                  "kstat chain updated");
        break;
    }

    return id;
}

/*
 * bincompat is not possible with certain kstat data structures between
 * solaris 2.6, 2.7, 2.8, etc.  alternative is to use kstat_data_lookup()
 * which means everytime we want a stat, must do a linear search
 * of ksp->ks_data.  eek.  so we meet half way and do the search for
 * each key once per sigar_t instance.  once the initial search has
 * been done, we have a table of offsets to quickly access the stats via
 * ksp->ks_data + offset.  this gives us bincompat without the overhead
 * of many kstat_data_lookup calls.
 */
static SIGAR_INLINE int kstat_named_offset(kstat_t *ksp, const char *name)
{
    unsigned int i;
    kstat_named_t *kn;

    for (i=0, kn=ksp->ks_data;
         i<ksp->ks_ndata;
         i++, kn++)
    {
        if (strEQ(kn->name, name)) {
            return i;
        }
    }

    return -2; /* not found */
}

static char *kstat_keys_system[] = {
    "boot_time",
    "avenrun_1min",
    "avenrun_5min",
    "avenrun_15min",
    NULL
};

static char *kstat_keys_mempages[] = {
    "pages_anon",
    "pages_exec",
    "pages_vnode",
    NULL
};

static char *kstat_keys_syspages[] = {
    "pagesfree",
    NULL
};

static char **kstat_keys[] = {
    kstat_keys_system,
    kstat_keys_mempages,
    kstat_keys_syspages,
};

void sigar_koffsets_lookup(kstat_t *ksp, int *offsets, int kidx)
{
    int i;
    char **keys = kstat_keys[kidx];

    for (i=0; keys[i]; i++) {
        offsets[i] = kstat_named_offset(ksp, keys[i]);
    }
}