/*
 * 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 2020 Oxide Computer Company
 * Copyright (c) 2013 Gary Mills
 * Copyright (c) 1998, 2010, Oracle and/or its affiliates. All rights reserved.
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/varargs.h>
#include <sys/systm.h>
#include <sys/cmn_err.h>
#include <sys/stream.h>
#include <sys/strsubr.h>
#include <sys/strsun.h>
#include <sys/sysmacros.h>
#include <sys/kmem.h>
#include <sys/log.h>
#include <sys/spl.h>
#include <sys/syslog.h>
#include <sys/console.h>
#include <sys/debug.h>
#include <sys/utsname.h>
#include <sys/id_space.h>
#include <sys/zone.h>
#include <sys/bootbanner.h>

log_zone_t log_global;
queue_t *log_consq;
queue_t *log_backlogq;
queue_t *log_intrq;

#define LOG_PRISIZE     8       /* max priority size: 7 characters + null */
#define LOG_FACSIZE     9       /* max priority size: 8 characters + null */

static krwlock_t log_rwlock;
static int log_rwlock_depth;
static int log_seq_no[SL_CONSOLE + 1];
static stdata_t log_fakestr;
static id_space_t *log_minorspace;
static log_t log_backlog;
static struct kmem_cache *log_cons_cache;       /* log_t cache */

static queue_t *log_recentq;
static queue_t *log_freeq;

static zone_key_t log_zone_key;

static char log_overflow_msg[] = "message overflow on /dev/log minor #%d%s\n";

static char log_pri[LOG_PRIMASK + 1][LOG_PRISIZE] = {
        "emerg",        "alert",        "crit",         "error",
        "warning",      "notice",       "info",         "debug"
};

static char log_fac[LOG_NFACILITIES + 1][LOG_FACSIZE] = {
        "kern",         "user",         "mail",         "daemon",
        "auth",         "syslog",       "lpr",          "news",
        "uucp",         "altcron",      "authpriv",     "ftp",
        "ntp",          "audit",        "console",      "cron",
        "local0",       "local1",       "local2",       "local3",
        "local4",       "local5",       "local6",       "local7",
        "unknown"
};
static int log_cons_constructor(void *, void *, int);
static void log_cons_destructor(void *, void *);

/*
 * Get exclusive access to the logging system; this includes all minor
 * devices.  We use an rwlock rather than a mutex because hold times
 * are potentially long, so we don't want to waste cycles in adaptive mutex
 * spin (rwlocks always block when contended).  Note that we explicitly
 * support recursive calls (e.g. printf() calls foo() calls printf()).
 *
 * Clients may use log_enter() / log_exit() to guarantee that a group
 * of messages is treated atomically (i.e. they appear in order and are
 * not interspersed with any other messages), e.g. for multiline printf().
 *
 * This could probably be changed to a per-zone lock if contention becomes
 * an issue.
 */
void
log_enter(void)
{
        if (rw_owner(&log_rwlock) != curthread)
                rw_enter(&log_rwlock, RW_WRITER);
        log_rwlock_depth++;
}

void
log_exit(void)
{
        if (--log_rwlock_depth == 0)
                rw_exit(&log_rwlock);
}

void
log_flushq(queue_t *q)
{
        mblk_t *mp;
        log_t *lp = (log_t *)q->q_ptr;

        /* lp will be NULL if the queue was created via log_makeq */
        while ((mp = getq_noenab(q, 0)) != NULL)
                log_sendmsg(mp, lp == NULL ? GLOBAL_ZONEID : lp->log_zoneid);
}

/*
 * Create a minimal queue with just enough fields filled in to support
 * canput(9F), putq(9F), and getq_noenab(9F).  We set QNOENB to ensure
 * that the queue will never be enabled.
 */
static queue_t *
log_makeq(size_t lowat, size_t hiwat, void *ibc)
{
        queue_t *q;

        q = kmem_zalloc(sizeof (queue_t), KM_SLEEP);
        q->q_stream = &log_fakestr;
        q->q_flag = QISDRV | QMTSAFE | QNOENB | QREADR | QUSE;
        q->q_nfsrv = q;
        q->q_lowat = lowat;
        q->q_hiwat = hiwat;
        mutex_init(QLOCK(q), NULL, MUTEX_DRIVER, ibc);

        return (q);
}

/*
 * Initialize the log structure for a new zone.
 */
static void *
log_zoneinit(zoneid_t zoneid)
{
        int i;
        log_zone_t *lzp;

        if (zoneid == GLOBAL_ZONEID)
                lzp = &log_global;      /* use statically allocated struct */
        else
                lzp = kmem_zalloc(sizeof (log_zone_t), KM_SLEEP);

        for (i = 0; i < LOG_NUMCLONES; i++) {
                lzp->lz_clones[i].log_minor =
                    (minor_t)id_alloc(log_minorspace);
                lzp->lz_clones[i].log_zoneid = zoneid;
        }
        return (lzp);
}

/*ARGSUSED*/
static void
log_zonefree(zoneid_t zoneid, void *arg)
{
        log_zone_t *lzp = arg;
        int i;

        ASSERT(lzp != &log_global && zoneid != GLOBAL_ZONEID);
        if (lzp == NULL)
                return;
        for (i = 0; i < LOG_NUMCLONES; i++)
                id_free(log_minorspace, lzp->lz_clones[i].log_minor);
        kmem_free(lzp, sizeof (log_zone_t));
}

static void
log_bootbanner_print(const char *line, uint_t num)
{
        const char *pfx = (num == 0) ? "\r" : "";

        printf("%s%s\n", pfx, line);
}

void
log_init(void)
{
        int log_maxzones;

        /*
         * Create a backlog queue to consume console messages during periods
         * when there is no console reader (e.g. before syslogd(8) starts).
         */
        log_backlogq = log_consq = log_makeq(0, LOG_HIWAT, NULL);

        /*
         * Create a queue to hold free message of size <= LOG_MSGSIZE.
         * Calls from high-level interrupt handlers will do a getq_noenab()
         * from this queue, so its q_lock must be a maximum SPL spin lock.
         */
        log_freeq = log_makeq(LOG_MINFREE, LOG_MAXFREE, (void *)ipltospl(SPL8));

        /*
         * Create a queue for messages from high-level interrupt context.
         * These messages are drained via softcall, or explicitly by panic().
         */
        log_intrq = log_makeq(0, LOG_HIWAT, (void *)ipltospl(SPL8));

        /*
         * Create a queue to hold the most recent 64K of console messages.
         * Useful for debugging.  Required by the "$<msgbuf" adb macro.
         */
        log_recentq = log_makeq(0, LOG_RECENTSIZE, NULL);

        /*
         * Create an id space for clone devices opened via /dev/log.
         * Need to limit the number of zones to avoid exceeding the
         * available minor number space.
         */
        log_maxzones = (L_MAXMIN32 - LOG_LOGMIN) / LOG_NUMCLONES - 1;
        if (log_maxzones < maxzones)
                maxzones = log_maxzones;
        log_minorspace = id_space_create("logminor_space", LOG_LOGMIN + 1,
            L_MAXMIN32);
        /*
         * Put ourselves on the ZSD list.  Note that zones have not been
         * initialized yet, but our constructor will be called on the global
         * zone when they are.
         */
        zone_key_create(&log_zone_key, log_zoneinit, NULL, log_zonefree);

        /*
         * Initialize backlog structure.
         */
        log_backlog.log_zoneid = GLOBAL_ZONEID;
        log_backlog.log_minor = LOG_BACKLOG;

        /* Allocate kmem cache for conslog's log structures */
        log_cons_cache = kmem_cache_create("log_cons_cache",
            sizeof (struct log), 0, log_cons_constructor, log_cons_destructor,
            NULL, NULL, NULL, 0);

        /*
         * Let the logging begin.
         */
        log_update(&log_backlog, log_backlogq, SL_CONSOLE, log_console);

        /*
         * Now that logging is enabled, emit the boot banner.
         */
#ifdef  LEGACY_BANNER
        printf("\rSunOS Release %s Version %s %u-bit\n",
            utsname.release, utsname.version, NBBY * (uint_t)sizeof (void *));
        printf("Copyright (c) 1983, 2010, Oracle and/or its affiliates. "
            "All rights reserved.\n");
#else
        bootbanner_print(log_bootbanner_print);
#endif
#ifdef DEBUG
        printf("DEBUG enabled\n");
#endif
}

/*
 * Allocate a log device corresponding to supplied device type.
 * Both devices are clonable. /dev/log devices are allocated per zone.
 * /dev/conslog devices are allocated from kmem cache.
 */
log_t *
log_alloc(minor_t type)
{
        zone_t *zptr = curproc->p_zone;
        log_zone_t *lzp;
        log_t *lp;
        int i;
        minor_t minor;

        if (type == LOG_CONSMIN) {

                /*
                 * Return a write-only /dev/conslog device.
                 * No point allocating log_t until there's a free minor number.
                 */
                minor = (minor_t)id_alloc(log_minorspace);
                lp = kmem_cache_alloc(log_cons_cache, KM_SLEEP);
                lp->log_minor = minor;
                return (lp);
        } else {
                ASSERT(type == LOG_LOGMIN);

                lzp = zone_getspecific(log_zone_key, zptr);
                ASSERT(lzp != NULL);

                /* search for an available /dev/log device for the zone */
                for (i = LOG_LOGMINIDX; i <= LOG_LOGMAXIDX; i++) {
                        lp = &lzp->lz_clones[i];
                        if (lp->log_inuse == 0)
                                break;
                }
                if (i > LOG_LOGMAXIDX)
                        lp = NULL;
                else
                        /* Indicate which device type */
                        lp->log_major = LOG_LOGMIN;
                return (lp);
        }
}

void
log_free(log_t *lp)
{
        id_free(log_minorspace, lp->log_minor);
        kmem_cache_free(log_cons_cache, lp);
}

/*
 * Move console messages from src to dst.  The time of day isn't known
 * early in boot, so fix up the message timestamps if necessary.
 */
static void
log_conswitch(log_t *src, log_t *dst)
{
        mblk_t *mp;
        mblk_t *hmp = NULL;
        mblk_t *tmp = NULL;
        log_ctl_t *hlc;

        while ((mp = getq_noenab(src->log_q, 0)) != NULL) {
                log_ctl_t *lc = (log_ctl_t *)mp->b_rptr;
                lc->flags |= SL_LOGONLY;

                /*
                 * The ttime is written with 0 in log_sensmsg() only when
                 * good gethrestime_sec() data is not available to store in
                 * the log_ctl_t in the early boot phase.
                 */
                if (lc->ttime == 0) {
                        /*
                         * Look ahead to first early boot message with time.
                         */
                        if (hmp) {
                                tmp->b_next = mp;
                                tmp = mp;
                        } else
                                hmp = tmp = mp;
                        continue;
                }

                while (hmp) {
                        tmp = hmp->b_next;
                        hmp->b_next = NULL;
                        hlc = (log_ctl_t *)hmp->b_rptr;
                        /*
                         * Calculate hrestime for an early log message with
                         * an invalid time stamp. We know:
                         *  - the lbolt of the invalid time stamp.
                         *  - the hrestime and lbolt of the first valid
                         *    time stamp.
                         */
                        hlc->ttime = lc->ttime - (lc->ltime - hlc->ltime) / hz;
                        (void) putq(dst->log_q, hmp);
                        hmp = tmp;
                }
                (void) putq(dst->log_q, mp);
        }
        while (hmp) {
                tmp = hmp->b_next;
                hmp->b_next = NULL;
                hlc = (log_ctl_t *)hmp->b_rptr;
                hlc->ttime = gethrestime_sec() -
                    (ddi_get_lbolt() - hlc->ltime) / hz;
                (void) putq(dst->log_q, hmp);
                hmp = tmp;
        }
        dst->log_overflow = src->log_overflow;
        src->log_flags = 0;
        dst->log_flags = SL_CONSOLE;
        log_consq = dst->log_q;
}

/*
 * Set the fields in the 'target' clone to the specified values.
 * Then, look at all clones to determine which message types are
 * currently active and which clone is the primary console queue.
 * If the primary console queue changes to or from the backlog
 * queue, copy all messages from backlog to primary or vice versa.
 */
void
log_update(log_t *target, queue_t *q, short flags, log_filter_t *filter)
{
        log_t *lp;
        short active = SL_CONSOLE;
        zone_t *zptr = NULL;
        log_zone_t *lzp;
        zoneid_t zoneid = target->log_zoneid;
        int i;

        log_enter();

        if (q != NULL)
                target->log_q = q;
        target->log_wanted = filter;
        target->log_flags = flags;
        target->log_overflow = 0;

        /*
         * Need to special case the global zone here since this may be
         * called before zone_init.
         */
        if (zoneid == GLOBAL_ZONEID) {
                lzp = &log_global;
        } else if ((zptr = zone_find_by_id(zoneid)) == NULL) {
                log_exit();
                return;         /* zone is being destroyed, ignore update */
        } else {
                lzp = zone_getspecific(log_zone_key, zptr);
        }
        ASSERT(lzp != NULL);
        for (i = LOG_LOGMAXIDX; i >= LOG_LOGMINIDX; i--) {
                lp = &lzp->lz_clones[i];
                if (zoneid == GLOBAL_ZONEID && (lp->log_flags & SL_CONSOLE))
                        log_consq = lp->log_q;
                active |= lp->log_flags;
        }
        lzp->lz_active = active;

        if (zptr)
                zone_rele(zptr);

        if (log_consq == target->log_q) {
                if (flags & SL_CONSOLE)
                        log_conswitch(&log_backlog, target);
                else
                        log_conswitch(target, &log_backlog);
        }
        target->log_q = q;

        log_exit();
}

/*ARGSUSED*/
int
log_error(log_t *lp, log_ctl_t *lc)
{
        if ((lc->pri & LOG_FACMASK) == LOG_KERN)
                lc->pri = LOG_KERN | LOG_ERR;
        return (1);
}

int
log_trace(log_t *lp, log_ctl_t *lc)
{
        trace_ids_t *tid = (trace_ids_t *)lp->log_data->b_rptr;
        trace_ids_t *tidend = (trace_ids_t *)lp->log_data->b_wptr;

        /*
         * We use `tid + 1 <= tidend' here rather than the more traditional
         * `tid < tidend', since the former ensures that there's at least
         * `sizeof (trace_ids_t)' bytes available before executing the
         * loop, whereas the latter only ensures that there's a single byte.
         */
        for (; tid + 1 <= tidend; tid++) {
                if (tid->ti_level < lc->level && tid->ti_level >= 0)
                        continue;
                if (tid->ti_mid != lc->mid && tid->ti_mid >= 0)
                        continue;
                if (tid->ti_sid != lc->sid && tid->ti_sid >= 0)
                        continue;
                if ((lc->pri & LOG_FACMASK) == LOG_KERN)
                        lc->pri = LOG_KERN | LOG_DEBUG;
                return (1);
        }
        return (0);
}

/*ARGSUSED*/
int
log_console(log_t *lp, log_ctl_t *lc)
{
        if ((lc->pri & LOG_FACMASK) == LOG_KERN) {
                if (lc->flags & SL_FATAL)
                        lc->pri = LOG_KERN | LOG_CRIT;
                else if (lc->flags & SL_ERROR)
                        lc->pri = LOG_KERN | LOG_ERR;
                else if (lc->flags & SL_WARN)
                        lc->pri = LOG_KERN | LOG_WARNING;
                else if (lc->flags & SL_NOTE)
                        lc->pri = LOG_KERN | LOG_NOTICE;
                else if (lc->flags & SL_TRACE)
                        lc->pri = LOG_KERN | LOG_DEBUG;
                else
                        lc->pri = LOG_KERN | LOG_INFO;
        }
        return (1);
}

mblk_t *
log_makemsg(int mid, int sid, int level, int sl, int pri, void *msg,
    size_t size, int on_intr)
{
        mblk_t *mp = NULL;
        mblk_t *mp2;
        log_ctl_t *lc;

        if (size <= LOG_MSGSIZE &&
            (on_intr || log_freeq->q_count > log_freeq->q_lowat))
                mp = getq_noenab(log_freeq, 0);

        if (mp == NULL) {
                if (on_intr ||
                    (mp = allocb(sizeof (log_ctl_t), BPRI_HI)) == NULL ||
                    (mp2 = allocb(MAX(size, LOG_MSGSIZE), BPRI_HI)) == NULL) {
                        freemsg(mp);
                        return (NULL);
                }
                DB_TYPE(mp) = M_PROTO;
                mp->b_wptr += sizeof (log_ctl_t);
                mp->b_cont = mp2;
        } else {
                mp2 = mp->b_cont;
                mp2->b_wptr = mp2->b_rptr;
        }

        lc = (log_ctl_t *)mp->b_rptr;
        lc->mid = mid;
        lc->sid = sid;
        lc->level = level;
        lc->flags = sl;
        lc->pri = pri;

        bcopy(msg, mp2->b_wptr, size - 1);
        mp2->b_wptr[size - 1] = '\0';
        mp2->b_wptr += strlen((char *)mp2->b_wptr) + 1;

        return (mp);
}

void
log_freemsg(mblk_t *mp)
{
        mblk_t *mp2 = mp->b_cont;

        ASSERT(MBLKL(mp) == sizeof (log_ctl_t));
        ASSERT(mp2->b_rptr == mp2->b_datap->db_base);

        if ((log_freeq->q_flag & QFULL) == 0 &&
            MBLKL(mp2) <= LOG_MSGSIZE && MBLKSIZE(mp2) >= LOG_MSGSIZE)
                (void) putq(log_freeq, mp);
        else
                freemsg(mp);
}

void
log_sendmsg(mblk_t *mp, zoneid_t zoneid)
{
        log_t *lp;
        char *src, *dst;
        mblk_t *mp2 = mp->b_cont;
        log_ctl_t *lc = (log_ctl_t *)mp->b_rptr;
        int flags, fac;
        off_t facility = 0;
        off_t body = 0;
        zone_t *zptr = NULL;
        log_zone_t *lzp;
        int i;
        int backlog;

        /*
         * Need to special case the global zone here since this may be
         * called before zone_init.
         */
        if (zoneid == GLOBAL_ZONEID) {
                lzp = &log_global;
        } else if ((zptr = zone_find_by_id(zoneid)) == NULL) {
                /* specified zone doesn't exist, free message and return */
                log_freemsg(mp);
                return;
        } else {
                lzp = zone_getspecific(log_zone_key, zptr);
        }
        ASSERT(lzp != NULL);

        if ((lc->flags & lzp->lz_active) == 0) {
                if (zptr)
                        zone_rele(zptr);
                log_freemsg(mp);
                return;
        }

        if (panicstr) {
                /*
                 * Raise the console queue's q_hiwat to ensure that we
                 * capture all panic messages.
                 */
                log_consq->q_hiwat = 2 * LOG_HIWAT;
                log_consq->q_flag &= ~QFULL;

                /* Message was created while panicking. */
                lc->flags |= SL_PANICMSG;
        }

        src = (char *)mp2->b_rptr;
        dst = strstr(src, "FACILITY_AND_PRIORITY] ");
        if (dst != NULL) {
                facility = dst - src;
                body = facility + 23; /* strlen("FACILITY_AND_PRIORITY] ") */
        }

        log_enter();

        /*
         * In the early boot phase hrestime is invalid, then timechanged is 0.
         * If hrestime is not valid, the ttime is set to 0 here and the correct
         * ttime is calculated in log_conswitch() later. The log_conswitch()
         * calculation to determine the correct ttime does not use ttime data
         * from these log_ctl_t structures; it only uses ttime from log_ctl_t's
         * that contain good data.
         *
         */
        lc->ltime = ddi_get_lbolt();
        if (timechanged) {
                lc->ttime = gethrestime_sec();
        } else {
                lc->ttime = 0;
        }

        flags = lc->flags & lzp->lz_active;
        log_seq_no[flags & SL_ERROR]++;
        log_seq_no[flags & SL_TRACE]++;
        log_seq_no[flags & SL_CONSOLE]++;

        /*
         * If this is in the global zone, start with the backlog, then
         * walk through the clone logs.  If not, just do the clone logs.
         */
        backlog = (zoneid == GLOBAL_ZONEID);
        i = LOG_LOGMINIDX;
        while (i <= LOG_LOGMAXIDX) {
                if (backlog) {
                        /*
                         * Do the backlog this time, then start on the
                         * others.
                         */
                        backlog = 0;
                        lp = &log_backlog;
                } else {
                        lp = &lzp->lz_clones[i++];
                }

                if ((lp->log_flags & flags) && lp->log_wanted(lp, lc)) {
                        if (canput(lp->log_q)) {
                                lp->log_overflow = 0;
                                lc->seq_no = log_seq_no[lp->log_flags];
                                if ((mp2 = copymsg(mp)) == NULL)
                                        break;
                                if (facility != 0) {
                                        src = (char *)mp2->b_cont->b_rptr;
                                        dst = src + facility;
                                        fac = (lc->pri & LOG_FACMASK) >> 3;
                                        dst += snprintf(dst,
                                            LOG_FACSIZE + LOG_PRISIZE, "%s.%s",
                                            log_fac[MIN(fac, LOG_NFACILITIES)],
                                            log_pri[lc->pri & LOG_PRIMASK]);
                                        src += body - 2; /* copy "] " too */
                                        while (*src != '\0')
                                                *dst++ = *src++;
                                        *dst++ = '\0';
                                        mp2->b_cont->b_wptr = (uchar_t *)dst;
                                }
                                (void) putq(lp->log_q, mp2);
                        } else if (++lp->log_overflow == 1) {
                                if (lp->log_q == log_consq) {
                                        console_printf(log_overflow_msg,
                                            lp->log_minor,
                                            " -- is syslogd(8) running?");
                                } else {
                                        printf(log_overflow_msg,
                                            lp->log_minor, "");
                                }
                        }
                }
        }

        if (zptr)
                zone_rele(zptr);

        if ((flags & SL_CONSOLE) && (lc->pri & LOG_FACMASK) == LOG_KERN) {
                if ((mp2 == NULL || log_consq == log_backlogq || panicstr) &&
                    (lc->flags & SL_LOGONLY) == 0)
                        console_printf("%s", (char *)mp->b_cont->b_rptr + body);
                if ((lc->flags & SL_CONSONLY) == 0 &&
                    (mp2 = copymsg(mp)) != NULL) {
                        mp2->b_cont->b_rptr += body;
                        if (log_recentq->q_flag & QFULL)
                                freemsg(getq_noenab(log_recentq, 0));
                        (void) putq(log_recentq, mp2);
                }
        }

        log_freemsg(mp);

        log_exit();
}

/*
 * Print queued messages to console.
 */
void
log_printq(queue_t *qfirst)
{
        mblk_t *mp;
        queue_t *q, *qlast;
        char *cp, *msgp;
        log_ctl_t *lc;

        /*
         * Look ahead to first queued message in the stream.
         */
        qlast = NULL;
        do {
                for (q = qfirst; q->q_next != qlast; q = q->q_next)
                        continue;
                for (mp = q->q_first; mp != NULL; mp = mp->b_next) {
                        lc = (log_ctl_t *)mp->b_rptr;
                        /*
                         * Check if message is already displayed at
                         * /dev/console.
                         */
                        if (lc->flags & SL_PANICMSG)
                                continue;

                        cp = (char *)mp->b_cont->b_rptr;

                        /* Strip off the message ID. */
                        if ((msgp = strstr(cp, "[ID ")) != NULL &&
                            (msgp = strstr(msgp,  "] ")) != NULL) {
                                cp = msgp + 2;
                        }

                        /*
                         * Using console_printf instead of printf to avoid
                         * queueing messages to log_consq.
                         */
                        console_printf("%s", cp);
                }
        } while ((qlast = q) != qfirst);
}

/* ARGSUSED */
static int
log_cons_constructor(void *buf, void *cdrarg, int kmflags)
{
        struct log *lp = buf;

        lp->log_zoneid = GLOBAL_ZONEID;
        lp->log_major = LOG_CONSMIN;    /* Indicate which device type */
        lp->log_data = NULL;
        return (0);
}

/* ARGSUSED */
static void
log_cons_destructor(void *buf, void *cdrarg)
{
        struct log *lp = buf;

        ASSERT(lp->log_zoneid == GLOBAL_ZONEID);
        ASSERT(lp->log_major == LOG_CONSMIN);
        ASSERT(lp->log_data == NULL);
}