/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2008 Yahoo!, Inc.
 * All rights reserved.
 * Written by: John Baldwin <jhb@FreeBSD.org>
 *
 * 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 author nor the names of any co-contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 */

#include <sys/param.h>
#include <sys/pcpu.h>
#include <sys/resource.h>
#include <sys/sysctl.h>
#include <errno.h>
#include <kvm.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>

#include "kvm_private.h"

static struct nlist kvm_cp_time_nl[] = {
        { .n_name = "_cp_time" },               /* (deprecated) */
        { .n_name = NULL },
};

#define NL_CP_TIME              0

static int kvm_cp_time_cached;

static int
_kvm_cp_time_init(kvm_t *kd)
{

        if (kvm_nlist(kd, kvm_cp_time_nl) < 0)
                return (-1);
        kvm_cp_time_cached = 1;
        return (0);
}

static int
getsysctl(kvm_t *kd, const char *name, void *buf, size_t len)
{
        size_t nlen;

        nlen = len;
        if (sysctlbyname(name, buf, &nlen, NULL, 0) < 0) {
                _kvm_err(kd, kd->program, "cannot read sysctl %s:%s", name,
                    strerror(errno));
                return (-1);
        }
        if (nlen != len) {
                _kvm_err(kd, kd->program, "sysctl %s has unexpected size",
                    name);
                return (-1);
        }
        return (0);
}

int
kvm_getcptime(kvm_t *kd, long *cp_time)
{
        struct pcpu *pc;
        int i, j, maxcpu;

        if (kd == NULL) {
                kvm_cp_time_cached = 0;
                return (0);
        }

        if (ISALIVE(kd))
                return (getsysctl(kd, "kern.cp_time", cp_time, sizeof(long) *
                    CPUSTATES));

        if (!kd->arch->ka_native(kd)) {
                _kvm_err(kd, kd->program,
                    "cannot read cp_time from non-native core");
                return (-1);
        }

        if (kvm_cp_time_cached == 0) {
                if (_kvm_cp_time_init(kd) < 0)
                        return (-1);
        }

        /* If this kernel has a "cp_time[]" symbol, then just read that. */
        if (kvm_cp_time_nl[NL_CP_TIME].n_value != 0) {
                if (kvm_read(kd, kvm_cp_time_nl[NL_CP_TIME].n_value, cp_time,
                    sizeof(long) * CPUSTATES) != sizeof(long) * CPUSTATES) {
                        _kvm_err(kd, kd->program, "cannot read cp_time array");
                        return (-1);
                }
                return (0);
        }

        /*
         * If we don't have that symbol, then we have to simulate
         * "cp_time[]" by adding up the individual times for each CPU.
         */
        maxcpu = kvm_getmaxcpu(kd);
        if (maxcpu < 0)
                return (-1);
        for (i = 0; i < CPUSTATES; i++)
                cp_time[i] = 0;
        for (i = 0; i < maxcpu; i++) {
                pc = kvm_getpcpu(kd, i);
                if (pc == NULL)
                        continue;
                if (pc == (void *)-1)
                        return (-1);
                for (j = 0; j < CPUSTATES; j++)
                        cp_time[j] += pc->pc_cp_time[j];
                free(pc);
        }
        return (0);
}