kern_shutdown.c

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/*-
 * Copyright (c) 1986, 1988, 1991, 1993
 *      The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * 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.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 *      @(#)kern_shutdown.c     8.3 (Berkeley) 1/21/94
 */

#include <sys/cdefs.h>
__FBSDID("$BSDSUniX$");

#include "opt_ddb.h"
#include "opt_kdb.h"
#include "opt_panic.h"
#include "opt_sched.h"
#include "opt_watchdog.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/conf.h>
#include <sys/cons.h>
#include <sys/eventhandler.h>
#include <sys/jail.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/kerneldump.h>
#include <sys/kthread.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/reboot.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/smp.h>
#include <sys/sysctl.h>
#include <sys/sysproto.h>
#include <sys/vnode.h>
#include <sys/watchdog.h>

#include <ddb/ddb.h>

#include <machine/cpu.h>
#include <machine/pcb.h>
#include <machine/smp.h>

#include <security/mac/mac_framework.h>

#include <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
#include <vm/swap_pager.h>

#include <sys/signalvar.h>

#ifndef PANIC_REBOOT_WAIT_TIME
#define PANIC_REBOOT_WAIT_TIME 15 /* default to 15 seconds */
#endif
static int panic_reboot_wait_time = PANIC_REBOOT_WAIT_TIME;
SYSCTL_INT(_kern, OID_AUTO, panic_reboot_wait_time, CTLFLAG_RW | CTLFLAG_TUN,
    &panic_reboot_wait_time, 0,
    "Seconds to wait before rebooting after a panic");
TUNABLE_INT("kern.panic_reboot_wait_time", &panic_reboot_wait_time);

/*
 * Note that stdarg.h and the ANSI style va_start macro is used for both
 * ANSI and traditional C compilers.
 */
#include <machine/stdarg.h>

#ifdef KDB
#ifdef KDB_UNATTENDED
int debugger_on_panic = 0;
#else
int debugger_on_panic = 1;
#endif
SYSCTL_INT(_debug, OID_AUTO, debugger_on_panic,
    CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_TUN,
    &debugger_on_panic, 0, "Run debugger on kernel panic");
TUNABLE_INT("debug.debugger_on_panic", &debugger_on_panic);

#ifdef KDB_TRACE
static int trace_on_panic = 1;
#else
static int trace_on_panic = 0;
#endif
SYSCTL_INT(_debug, OID_AUTO, trace_on_panic,
    CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_TUN,
    &trace_on_panic, 0, "Print stack trace on kernel panic");
TUNABLE_INT("debug.trace_on_panic", &trace_on_panic);
#endif /* KDB */

static int sync_on_panic = 0;
SYSCTL_INT(_kern, OID_AUTO, sync_on_panic, CTLFLAG_RW | CTLFLAG_TUN,
        &sync_on_panic, 0, "Do a sync before rebooting from a panic");
TUNABLE_INT("kern.sync_on_panic", &sync_on_panic);

static int stop_scheduler_on_panic = 1;
SYSCTL_INT(_kern, OID_AUTO, stop_scheduler_on_panic, CTLFLAG_RW | CTLFLAG_TUN,
    &stop_scheduler_on_panic, 0, "stop scheduler upon entering panic");
TUNABLE_INT("kern.stop_scheduler_on_panic", &stop_scheduler_on_panic);

static SYSCTL_NODE(_kern, OID_AUTO, shutdown, CTLFLAG_RW, 0,
    "Shutdown environment");

#ifndef DIAGNOSTIC
static int show_busybufs;
#else
static int show_busybufs = 1;
#endif
SYSCTL_INT(_kern_shutdown, OID_AUTO, show_busybufs, CTLFLAG_RW,
        &show_busybufs, 0, "");

/*
 * Variable panicstr contains argument to first call to panic; used as flag
 * to indicate that the kernel has already called panic.
 */
const char *panicstr;

int dumping;                            /* system is dumping */
int rebooting;                          /* system is rebooting */
static struct dumperinfo dumper;        /* our selected dumper */

/* Context information for dump-debuggers. */
static struct pcb dumppcb;              /* Registers. */
lwpid_t dumptid;                        /* Thread ID. */

static void poweroff_wait(void *, int);
static void shutdown_halt(void *junk, int howto);
static void shutdown_panic(void *junk, int howto);
static void shutdown_reset(void *junk, int howto);

/* register various local shutdown events */
static void
shutdown_conf(void *unused)
{

        EVENTHANDLER_REGISTER(shutdown_final, poweroff_wait, NULL,
            SHUTDOWN_PRI_FIRST);
        EVENTHANDLER_REGISTER(shutdown_final, shutdown_halt, NULL,
            SHUTDOWN_PRI_LAST + 100);
        EVENTHANDLER_REGISTER(shutdown_final, shutdown_panic, NULL,
            SHUTDOWN_PRI_LAST + 100);
        EVENTHANDLER_REGISTER(shutdown_final, shutdown_reset, NULL,
            SHUTDOWN_PRI_LAST + 200);
}

SYSINIT(shutdown_conf, SI_SUB_INTRINSIC, SI_ORDER_ANY, shutdown_conf, NULL);

/*
 * The system call that results in a reboot.
 */
/* ARGSUSED */
int
sys_reboot(struct thread *td, struct reboot_args *uap)
{
        int error;

        error = 0;
#ifdef MAC
        error = mac_system_check_reboot(td->td_ucred, uap->opt);
#endif
        if (error == 0)
                error = priv_check(td, PRIV_REBOOT);
        if (error == 0) {
                mtx_lock(&Giant);
                kern_reboot(uap->opt);
                mtx_unlock(&Giant);
        }
        return (error);
}

/*
 * Called by events that want to shut down.. e.g  <CTL><ALT><DEL> on a PC
 */
static int shutdown_howto = 0;

void
shutdown_nice(int howto)
{

        shutdown_howto = howto;

        /* Send a signal to init(8) and have it shutdown the world */
        if (initproc != NULL) {
                PROC_LOCK(initproc);
                kern_psignal(initproc, SIGINT);
                PROC_UNLOCK(initproc);
        } else {
                /* No init(8) running, so simply reboot */
                kern_reboot(RB_NOSYNC);
        }
        return;
}
static int      waittime = -1;

static void
print_uptime(void)
{
        int f;
        struct timespec ts;

        getnanouptime(&ts);
        printf("Uptime: ");
        f = 0;
        if (ts.tv_sec >= 86400) {
                printf("%ldd", (long)ts.tv_sec / 86400);
                ts.tv_sec %= 86400;
                f = 1;
        }
        if (f || ts.tv_sec >= 3600) {
                printf("%ldh", (long)ts.tv_sec / 3600);
                ts.tv_sec %= 3600;
                f = 1;
        }
        if (f || ts.tv_sec >= 60) {
                printf("%ldm", (long)ts.tv_sec / 60);
                ts.tv_sec %= 60;
                f = 1;
        }
        printf("%lds\n", (long)ts.tv_sec);
}

int
doadump(boolean_t textdump)
{
        boolean_t coredump;

        if (dumping)
                return (EBUSY);
        if (dumper.dumper == NULL)
                return (ENXIO);

        savectx(&dumppcb);
        dumptid = curthread->td_tid;
        dumping++;

        coredump = TRUE;
#ifdef DDB
        if (textdump && textdump_pending) {
                coredump = FALSE;
                textdump_dumpsys(&dumper);
        }
#endif
        if (coredump)
                dumpsys(&dumper);

        dumping--;
        return (0);
}

static int
isbufbusy(struct buf *bp)
{
        if (((bp->b_flags & (B_INVAL | B_PERSISTENT)) == 0 &&
            BUF_ISLOCKED(bp)) ||
            ((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI))
                return (1);
        return (0);
}

/*
 * Shutdown the system cleanly to prepare for reboot, halt, or power off.
 */
void
kern_reboot(int howto)
{
        static int first_buf_printf = 1;

#if defined(SMP)
        /*
         * Bind us to CPU 0 so that all shutdown code runs there.  Some
         * systems don't shutdown properly (i.e., ACPI power off) if we
         * run on another processor.
         */
        if (!SCHEDULER_STOPPED()) {
                thread_lock(curthread);
                sched_bind(curthread, 0);
                thread_unlock(curthread);
                KASSERT(PCPU_GET(cpuid) == 0, ("boot: not running on cpu 0"));
        }
#endif
        /* We're in the process of rebooting. */
        rebooting = 1;

        /* collect extra flags that shutdown_nice might have set */
        howto |= shutdown_howto;

        /* We are out of the debugger now. */
        kdb_active = 0;

        /*
         * Do any callouts that should be done BEFORE syncing the filesystems.
         */
        EVENTHANDLER_INVOKE(shutdown_pre_sync, howto);

        /* 
         * Now sync filesystems
         */
        if (!cold && (howto & RB_NOSYNC) == 0 && waittime < 0) {
                register struct buf *bp;
                int iter, nbusy, pbusy;
#ifndef PREEMPTION
                int subiter;
#endif

                waittime = 0;

                wdog_kern_pat(WD_LASTVAL);
                sys_sync(curthread, NULL);

                /*
                 * With soft updates, some buffers that are
                 * written will be remarked as dirty until other
                 * buffers are written.
                 */
                for (iter = pbusy = 0; iter < 20; iter++) {
                        nbusy = 0;
                        for (bp = &buf[nbuf]; --bp >= buf; )
                                if (isbufbusy(bp))
                                        nbusy++;
                        if (nbusy == 0) {
                                if (first_buf_printf)
                                        printf("All buffers synced.");
                                break;
                        }
                        if (first_buf_printf) {
                                printf("Syncing disks, buffers remaining... ");
                                first_buf_printf = 0;
                        }
                        printf("%d ", nbusy);
                        if (nbusy < pbusy)
                                iter = 0;
                        pbusy = nbusy;

                        wdog_kern_pat(WD_LASTVAL);
                        sys_sync(curthread, NULL);

#ifdef PREEMPTION
                        /*
                         * Drop Giant and spin for a while to allow
                         * interrupt threads to run.
                         */
                        DROP_GIANT();
                        DELAY(50000 * iter);
                        PICKUP_GIANT();
#else
                        /*
                         * Drop Giant and context switch several times to
                         * allow interrupt threads to run.
                         */
                        DROP_GIANT();
                        for (subiter = 0; subiter < 50 * iter; subiter++) {
                                thread_lock(curthread);
                                mi_switch(SW_VOL, NULL);
                                thread_unlock(curthread);
                                DELAY(1000);
                        }
                        PICKUP_GIANT();
#endif
                }
                printf("\n");
                /*
                 * Count only busy local buffers to prevent forcing 
                 * a fsck if we're just a client of a wedged NFS server
                 */
                nbusy = 0;
                for (bp = &buf[nbuf]; --bp >= buf; ) {
                        if (isbufbusy(bp)) {
#if 0
/* XXX: This is bogus.  We should probably have a BO_REMOTE flag instead */
                                if (bp->b_dev == NULL) {
                                        TAILQ_REMOVE(&mountlist,
                                            bp->b_vp->v_mount, mnt_list);
                                        continue;
                                }
#endif
                                nbusy++;
                                if (show_busybufs > 0) {
                                        printf(
            "%d: buf:%p, vnode:%p, flags:%0x, blkno:%jd, lblkno:%jd, buflock:",
                                            nbusy, bp, bp->b_vp, bp->b_flags,
                                            (intmax_t)bp->b_blkno,
                                            (intmax_t)bp->b_lblkno);
                                        BUF_LOCKPRINTINFO(bp);
                                        if (show_busybufs > 1)
                                                vn_printf(bp->b_vp,
                                                    "vnode content: ");
                                }
                        }
                }
                if (nbusy) {
                        /*
                         * Failed to sync all blocks. Indicate this and don't
                         * unmount filesystems (thus forcing an fsck on reboot).
                         */
                        printf("Giving up on %d buffers\n", nbusy);
                        DELAY(5000000); /* 5 seconds */
                } else {
                        if (!first_buf_printf)
                                printf("Final sync complete\n");
                        /*
                         * Unmount filesystems
                         */
                        if (panicstr == 0)
                                vfs_unmountall();
                }
                swapoff_all();
                DELAY(100000);          /* wait for console output to finish */
        }

        print_uptime();

        cngrab();

        /*
         * Ok, now do things that assume all filesystem activity has
         * been completed.
         */
        EVENTHANDLER_INVOKE(shutdown_post_sync, howto);

        if ((howto & (RB_HALT|RB_DUMP)) == RB_DUMP && !cold && !dumping) 
                doadump(TRUE);

        /* Now that we're going to really halt the system... */
        EVENTHANDLER_INVOKE(shutdown_final, howto);

        for(;;) ;       /* safety against shutdown_reset not working */
        /* NOTREACHED */
}

/*
 * If the shutdown was a clean halt, behave accordingly.
 */
static void
shutdown_halt(void *junk, int howto)
{

        if (howto & RB_HALT) {
                printf("\n");
                printf("The operating system has halted.\n");
                printf("Please press any key to reboot.\n\n");
                switch (cngetc()) {
                case -1:                /* No console, just die */
                        cpu_halt();
                        /* NOTREACHED */
                default:
                        howto &= ~RB_HALT;
                        break;
                }
        }
}

/*
 * Check to see if the system paniced, pause and then reboot
 * according to the specified delay.
 */
static void
shutdown_panic(void *junk, int howto)
{
        int loop;

        if (howto & RB_DUMP) {
                if (panic_reboot_wait_time != 0) {
                        if (panic_reboot_wait_time != -1) {
                                printf("Automatic reboot in %d seconds - "
                                       "press a key on the console to abort\n",
                                        panic_reboot_wait_time);
                                for (loop = panic_reboot_wait_time * 10;
                                     loop > 0; --loop) {
                                        DELAY(1000 * 100); /* 1/10th second */
                                        /* Did user type a key? */
                                        if (cncheckc() != -1)
                                                break;
                                }
                                if (!loop)
                                        return;
                        }
                } else { /* zero time specified - reboot NOW */
                        return;
                }
                printf("--> Press a key on the console to reboot,\n");
                printf("--> or switch off the system now.\n");
                cngetc();
        }
}

/*
 * Everything done, now reset
 */
static void
shutdown_reset(void *junk, int howto)
{

        printf("Rebooting...\n");
        DELAY(1000000); /* wait 1 sec for printf's to complete and be read */

        /*
         * Acquiring smp_ipi_mtx here has a double effect:
         * - it disables interrupts avoiding CPU0 preemption
         *   by fast handlers (thus deadlocking  against other CPUs)
         * - it avoids deadlocks against smp_rendezvous() or, more 
         *   generally, threads busy-waiting, with this spinlock held,
         *   and waiting for responses by threads on other CPUs
         *   (ie. smp_tlb_shootdown()).
         *
         * For the !SMP case it just needs to handle the former problem.
         */
#ifdef SMP
        mtx_lock_spin(&smp_ipi_mtx);
#else
        spinlock_enter();
#endif

        /* cpu_boot(howto); */ /* doesn't do anything at the moment */
        cpu_reset();
        /* NOTREACHED */ /* assuming reset worked */
}

/*
 * Panic is called on unresolvable fatal errors.  It prints "panic: mesg",
 * and then reboots.  If we are called twice, then we avoid trying to sync
 * the disks as this often leads to recursive panics.
 */
void
panic(const char *fmt, ...)
{
#ifdef SMP
        static volatile u_int panic_cpu = NOCPU;
        cpuset_t other_cpus;
#endif
        struct thread *td = curthread;
        int bootopt, newpanic;
        va_list ap;
        static char buf[256];

        if (stop_scheduler_on_panic)
                spinlock_enter();
        else
                critical_enter();

#ifdef SMP
        /*
         * We don't want multiple CPU's to panic at the same time, so we
         * use panic_cpu as a simple spinlock.  We have to keep checking
         * panic_cpu if we are spinning in case the panic on the first
         * CPU is canceled.
         */
        if (panic_cpu != PCPU_GET(cpuid))
                while (atomic_cmpset_int(&panic_cpu, NOCPU,
                    PCPU_GET(cpuid)) == 0)
                        while (panic_cpu != NOCPU)
                                ; /* nothing */

        if (stop_scheduler_on_panic) {
                if (panicstr == NULL && !kdb_active) {
                        other_cpus = all_cpus;
                        CPU_CLR(PCPU_GET(cpuid), &other_cpus);
                        stop_cpus_hard(other_cpus);
                }

                /*
                 * We set stop_scheduler here and not in the block above,
                 * because we want to ensure that if panic has been called and
                 * stop_scheduler_on_panic is true, then stop_scheduler will
                 * always be set.  Even if panic has been entered from kdb.
                 */
                td->td_stopsched = 1;
        }
#endif

        bootopt = RB_AUTOBOOT;
        newpanic = 0;
        if (panicstr)
                bootopt |= RB_NOSYNC;
        else {
                bootopt |= RB_DUMP;
                panicstr = fmt;
                newpanic = 1;
        }

        va_start(ap, fmt);
        if (newpanic) {
                (void)vsnprintf(buf, sizeof(buf), fmt, ap);
                panicstr = buf;
                cngrab();
                printf("panic: %s\n", buf);
        } else {
                printf("panic: ");
                vprintf(fmt, ap);
                printf("\n");
        }
        va_end(ap);
#ifdef SMP
        printf("cpuid = %d\n", PCPU_GET(cpuid));
#endif

#ifdef KDB
        if (newpanic && trace_on_panic)
                kdb_backtrace();
        if (debugger_on_panic)
                kdb_enter(KDB_WHY_PANIC, "panic");
#endif
        /*thread_lock(td); */
        td->td_flags |= TDF_INPANIC;
        /* thread_unlock(td); */
        if (!sync_on_panic)
                bootopt |= RB_NOSYNC;
        if (!stop_scheduler_on_panic)
                critical_exit();
        kern_reboot(bootopt);
}

/*
 * Support for poweroff delay.
 *
 * Please note that setting this delay too short might power off your machine
 * before the write cache on your hard disk has been flushed, leading to
 * soft-updates inconsistencies.
 */
#ifndef POWEROFF_DELAY
# define POWEROFF_DELAY 5000
#endif
static int poweroff_delay = POWEROFF_DELAY;

SYSCTL_INT(_kern_shutdown, OID_AUTO, poweroff_delay, CTLFLAG_RW,
        &poweroff_delay, 0, "");

static void
poweroff_wait(void *junk, int howto)
{

        if (!(howto & RB_POWEROFF) || poweroff_delay <= 0)
                return;
        DELAY(poweroff_delay * 1000);
}

/*
 * Some system processes (e.g. syncer) need to be stopped at appropriate
 * points in their main loops prior to a system shutdown, so that they
 * won't interfere with the shutdown process (e.g. by holding a disk buf
 * to cause sync to fail).  For each of these system processes, register
 * shutdown_kproc() as a handler for one of shutdown events.
 */
static int kproc_shutdown_wait = 60;
SYSCTL_INT(_kern_shutdown, OID_AUTO, kproc_shutdown_wait, CTLFLAG_RW,
    &kproc_shutdown_wait, 0, "");

void
kproc_shutdown(void *arg, int howto)
{
        struct proc *p;
        int error;

        if (panicstr)
                return;

        p = (struct proc *)arg;
        printf("Waiting (max %d seconds) for system process `%s' to stop...",
            kproc_shutdown_wait, p->p_comm);
        error = kproc_suspend(p, kproc_shutdown_wait * hz);

        if (error == EWOULDBLOCK)
                printf("timed out\n");
        else
                printf("done\n");
}

void
kthread_shutdown(void *arg, int howto)
{
        struct thread *td;
        int error;

        if (panicstr)
                return;

        td = (struct thread *)arg;
        printf("Waiting (max %d seconds) for system thread `%s' to stop...",
            kproc_shutdown_wait, td->td_name);
        error = kthread_suspend(td, kproc_shutdown_wait * hz);

        if (error == EWOULDBLOCK)
                printf("timed out\n");
        else
                printf("done\n");
}

/* Registration of dumpers */
int
set_dumper(struct dumperinfo *di)
{

        if (di == NULL) {
                bzero(&dumper, sizeof dumper);
                return (0);
        }
        if (dumper.dumper != NULL)
                return (EBUSY);
        dumper = *di;
        return (0);
}

/* Call dumper with bounds checking. */
int
dump_write(struct dumperinfo *di, void *virtual, vm_offset_t physical,
    off_t offset, size_t length)
{

        if (length != 0 && (offset < di->mediaoffset ||
            offset - di->mediaoffset + length > di->mediasize)) {
                printf("Attempt to write outside dump device boundaries.\n"
            "offset(%jd), mediaoffset(%jd), length(%ju), mediasize(%jd).\n",
                    (intmax_t)offset, (intmax_t)di->mediaoffset,
                    (uintmax_t)length, (intmax_t)di->mediasize);
                return (ENOSPC);
        }
        return (di->dumper(di->priv, virtual, physical, offset, length));
}

void
mkdumpheader(struct kerneldumpheader *kdh, char *magic, uint32_t archver,
    uint64_t dumplen, uint32_t blksz)
{

        bzero(kdh, sizeof(*kdh));
        strncpy(kdh->magic, magic, sizeof(kdh->magic));
        strncpy(kdh->architecture, MACHINE_ARCH, sizeof(kdh->architecture));
        kdh->version = htod32(KERNELDUMPVERSION);
        kdh->architectureversion = htod32(archver);
        kdh->dumplength = htod64(dumplen);
        kdh->dumptime = htod64(time_second);
        kdh->blocksize = htod32(blksz);
        strncpy(kdh->hostname, prison0.pr_hostname, sizeof(kdh->hostname));
        strncpy(kdh->versionstring, version, sizeof(kdh->versionstring));
        if (panicstr != NULL)
                strncpy(kdh->panicstring, panicstr, sizeof(kdh->panicstring));
        kdh->parity = kerneldump_parity(kdh);
}