The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_shutdown.c

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    1 /*-
    2  * Copyright (c) 1986, 1988, 1991, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  * (c) UNIX System Laboratories, Inc.
    5  * All or some portions of this file are derived from material licensed
    6  * to the University of California by American Telephone and Telegraph
    7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
    8  * the permission of UNIX System Laboratories, Inc.
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Redistributions in binary form must reproduce the above copyright
   16  *    notice, this list of conditions and the following disclaimer in the
   17  *    documentation and/or other materials provided with the distribution.
   18  * 4. Neither the name of the University nor the names of its contributors
   19  *    may be used to endorse or promote products derived from this software
   20  *    without specific prior written permission.
   21  *
   22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   32  * SUCH DAMAGE.
   33  *
   34  *      @(#)kern_shutdown.c     8.3 (Berkeley) 1/21/94
   35  */
   36 
   37 #include <sys/cdefs.h>
   38 __FBSDID("$FreeBSD$");
   39 
   40 #include "opt_ddb.h"
   41 #include "opt_kdb.h"
   42 #include "opt_panic.h"
   43 #include "opt_sched.h"
   44 #include "opt_watchdog.h"
   45 
   46 #include <sys/param.h>
   47 #include <sys/systm.h>
   48 #include <sys/bio.h>
   49 #include <sys/buf.h>
   50 #include <sys/conf.h>
   51 #include <sys/cons.h>
   52 #include <sys/eventhandler.h>
   53 #include <sys/filedesc.h>
   54 #include <sys/jail.h>
   55 #include <sys/kdb.h>
   56 #include <sys/kernel.h>
   57 #include <sys/kerneldump.h>
   58 #include <sys/kthread.h>
   59 #include <sys/ktr.h>
   60 #include <sys/malloc.h>
   61 #include <sys/mount.h>
   62 #include <sys/priv.h>
   63 #include <sys/proc.h>
   64 #include <sys/reboot.h>
   65 #include <sys/resourcevar.h>
   66 #include <sys/rwlock.h>
   67 #include <sys/sched.h>
   68 #include <sys/smp.h>
   69 #include <sys/sysctl.h>
   70 #include <sys/sysproto.h>
   71 #include <sys/taskqueue.h>
   72 #include <sys/vnode.h>
   73 #include <sys/watchdog.h>
   74 
   75 #include <ddb/ddb.h>
   76 
   77 #include <machine/cpu.h>
   78 #include <machine/dump.h>
   79 #include <machine/pcb.h>
   80 #include <machine/smp.h>
   81 
   82 #include <security/mac/mac_framework.h>
   83 
   84 #include <vm/vm.h>
   85 #include <vm/vm_object.h>
   86 #include <vm/vm_page.h>
   87 #include <vm/vm_pager.h>
   88 #include <vm/swap_pager.h>
   89 
   90 #include <sys/signalvar.h>
   91 
   92 static MALLOC_DEFINE(M_DUMPER, "dumper", "dumper block buffer");
   93 
   94 #ifndef PANIC_REBOOT_WAIT_TIME
   95 #define PANIC_REBOOT_WAIT_TIME 15 /* default to 15 seconds */
   96 #endif
   97 static int panic_reboot_wait_time = PANIC_REBOOT_WAIT_TIME;
   98 SYSCTL_INT(_kern, OID_AUTO, panic_reboot_wait_time, CTLFLAG_RWTUN,
   99     &panic_reboot_wait_time, 0,
  100     "Seconds to wait before rebooting after a panic");
  101 
  102 /*
  103  * Note that stdarg.h and the ANSI style va_start macro is used for both
  104  * ANSI and traditional C compilers.
  105  */
  106 #include <machine/stdarg.h>
  107 
  108 #ifdef KDB
  109 #ifdef KDB_UNATTENDED
  110 static int debugger_on_panic = 0;
  111 #else
  112 static int debugger_on_panic = 1;
  113 #endif
  114 SYSCTL_INT(_debug, OID_AUTO, debugger_on_panic,
  115     CTLFLAG_RWTUN | CTLFLAG_SECURE,
  116     &debugger_on_panic, 0, "Run debugger on kernel panic");
  117 
  118 int debugger_on_trap = 0;
  119 SYSCTL_INT(_debug, OID_AUTO, debugger_on_trap,
  120     CTLFLAG_RWTUN | CTLFLAG_SECURE,
  121     &debugger_on_trap, 0, "Run debugger on kernel trap before panic");
  122 
  123 #ifdef KDB_TRACE
  124 static int trace_on_panic = 1;
  125 #else
  126 static int trace_on_panic = 0;
  127 #endif
  128 SYSCTL_INT(_debug, OID_AUTO, trace_on_panic,
  129     CTLFLAG_RWTUN | CTLFLAG_SECURE,
  130     &trace_on_panic, 0, "Print stack trace on kernel panic");
  131 #endif /* KDB */
  132 
  133 static int sync_on_panic = 0;
  134 SYSCTL_INT(_kern, OID_AUTO, sync_on_panic, CTLFLAG_RWTUN,
  135         &sync_on_panic, 0, "Do a sync before rebooting from a panic");
  136 
  137 static SYSCTL_NODE(_kern, OID_AUTO, shutdown, CTLFLAG_RW, 0,
  138     "Shutdown environment");
  139 
  140 #ifndef DIAGNOSTIC
  141 static int show_busybufs;
  142 #else
  143 static int show_busybufs = 1;
  144 #endif
  145 SYSCTL_INT(_kern_shutdown, OID_AUTO, show_busybufs, CTLFLAG_RW,
  146         &show_busybufs, 0, "");
  147 
  148 int suspend_blocked = 0;
  149 SYSCTL_INT(_kern, OID_AUTO, suspend_blocked, CTLFLAG_RW,
  150         &suspend_blocked, 0, "Block suspend due to a pending shutdown");
  151 
  152 /*
  153  * Variable panicstr contains argument to first call to panic; used as flag
  154  * to indicate that the kernel has already called panic.
  155  */
  156 const char *panicstr;
  157 
  158 int dumping;                            /* system is dumping */
  159 int rebooting;                          /* system is rebooting */
  160 static struct dumperinfo dumper;        /* our selected dumper */
  161 
  162 /* Context information for dump-debuggers. */
  163 static struct pcb dumppcb;              /* Registers. */
  164 lwpid_t dumptid;                        /* Thread ID. */
  165 
  166 static struct cdevsw reroot_cdevsw = {
  167      .d_version = D_VERSION,
  168      .d_name    = "reroot",
  169 };
  170 
  171 static void poweroff_wait(void *, int);
  172 static void shutdown_halt(void *junk, int howto);
  173 static void shutdown_panic(void *junk, int howto);
  174 static void shutdown_reset(void *junk, int howto);
  175 static int kern_reroot(void);
  176 
  177 /* register various local shutdown events */
  178 static void
  179 shutdown_conf(void *unused)
  180 {
  181 
  182         EVENTHANDLER_REGISTER(shutdown_final, poweroff_wait, NULL,
  183             SHUTDOWN_PRI_FIRST);
  184         EVENTHANDLER_REGISTER(shutdown_final, shutdown_halt, NULL,
  185             SHUTDOWN_PRI_LAST + 100);
  186         EVENTHANDLER_REGISTER(shutdown_final, shutdown_panic, NULL,
  187             SHUTDOWN_PRI_LAST + 100);
  188         EVENTHANDLER_REGISTER(shutdown_final, shutdown_reset, NULL,
  189             SHUTDOWN_PRI_LAST + 200);
  190 }
  191 
  192 SYSINIT(shutdown_conf, SI_SUB_INTRINSIC, SI_ORDER_ANY, shutdown_conf, NULL);
  193 
  194 /*
  195  * The only reason this exists is to create the /dev/reroot/ directory,
  196  * used by reroot code in init(8) as a mountpoint for tmpfs.
  197  */
  198 static void
  199 reroot_conf(void *unused)
  200 {
  201         int error;
  202         struct cdev *cdev;
  203 
  204         error = make_dev_p(MAKEDEV_CHECKNAME | MAKEDEV_WAITOK, &cdev,
  205             &reroot_cdevsw, NULL, UID_ROOT, GID_WHEEL, 0600, "reroot/reroot");
  206         if (error != 0) {
  207                 printf("%s: failed to create device node, error %d",
  208                     __func__, error);
  209         }
  210 }
  211 
  212 SYSINIT(reroot_conf, SI_SUB_DEVFS, SI_ORDER_ANY, reroot_conf, NULL);
  213 
  214 /*
  215  * The system call that results in a reboot.
  216  */
  217 /* ARGSUSED */
  218 int
  219 sys_reboot(struct thread *td, struct reboot_args *uap)
  220 {
  221         int error;
  222 
  223         error = 0;
  224 #ifdef MAC
  225         error = mac_system_check_reboot(td->td_ucred, uap->opt);
  226 #endif
  227         if (error == 0)
  228                 error = priv_check(td, PRIV_REBOOT);
  229         if (error == 0) {
  230                 if (uap->opt & RB_REROOT) {
  231                         error = kern_reroot();
  232                 } else {
  233                         mtx_lock(&Giant);
  234                         kern_reboot(uap->opt);
  235                         mtx_unlock(&Giant);
  236                 }
  237         }
  238         return (error);
  239 }
  240 
  241 static void
  242 shutdown_nice_task_fn(void *arg, int pending __unused)
  243 {
  244         int howto;
  245 
  246         howto = (uintptr_t)arg;
  247         /* Send a signal to init(8) and have it shutdown the world. */
  248         PROC_LOCK(initproc);
  249         if (howto & RB_POWEROFF)
  250                 kern_psignal(initproc, SIGUSR2);
  251         else if (howto & RB_HALT)
  252                 kern_psignal(initproc, SIGUSR1);
  253         else
  254                 kern_psignal(initproc, SIGINT);
  255         PROC_UNLOCK(initproc);
  256 }
  257 
  258 static struct task shutdown_nice_task = TASK_INITIALIZER(0,
  259     &shutdown_nice_task_fn, NULL);
  260 
  261 /*
  262  * Called by events that want to shut down.. e.g  <CTL><ALT><DEL> on a PC
  263  */
  264 void
  265 shutdown_nice(int howto)
  266 {
  267 
  268         if (initproc != NULL && !SCHEDULER_STOPPED()) {
  269                 shutdown_nice_task.ta_context = (void *)(uintptr_t)howto;
  270                 taskqueue_enqueue(taskqueue_fast, &shutdown_nice_task);
  271         } else {
  272                 /*
  273                  * No init(8) running, or scheduler would not allow it
  274                  * to run, so simply reboot.
  275                  */
  276                 kern_reboot(howto | RB_NOSYNC);
  277         }
  278 }
  279 
  280 static void
  281 print_uptime(void)
  282 {
  283         int f;
  284         struct timespec ts;
  285 
  286         getnanouptime(&ts);
  287         printf("Uptime: ");
  288         f = 0;
  289         if (ts.tv_sec >= 86400) {
  290                 printf("%ldd", (long)ts.tv_sec / 86400);
  291                 ts.tv_sec %= 86400;
  292                 f = 1;
  293         }
  294         if (f || ts.tv_sec >= 3600) {
  295                 printf("%ldh", (long)ts.tv_sec / 3600);
  296                 ts.tv_sec %= 3600;
  297                 f = 1;
  298         }
  299         if (f || ts.tv_sec >= 60) {
  300                 printf("%ldm", (long)ts.tv_sec / 60);
  301                 ts.tv_sec %= 60;
  302                 f = 1;
  303         }
  304         printf("%lds\n", (long)ts.tv_sec);
  305 }
  306 
  307 int
  308 doadump(boolean_t textdump)
  309 {
  310         boolean_t coredump;
  311         int error;
  312 
  313         error = 0;
  314         if (dumping)
  315                 return (EBUSY);
  316         if (dumper.dumper == NULL)
  317                 return (ENXIO);
  318 
  319         savectx(&dumppcb);
  320         dumptid = curthread->td_tid;
  321         dumping++;
  322 
  323         coredump = TRUE;
  324 #ifdef DDB
  325         if (textdump && textdump_pending) {
  326                 coredump = FALSE;
  327                 textdump_dumpsys(&dumper);
  328         }
  329 #endif
  330         if (coredump)
  331                 error = dumpsys(&dumper);
  332 
  333         dumping--;
  334         return (error);
  335 }
  336 
  337 /*
  338  * Shutdown the system cleanly to prepare for reboot, halt, or power off.
  339  */
  340 void
  341 kern_reboot(int howto)
  342 {
  343         static int once = 0;
  344 
  345 #if defined(SMP)
  346         /*
  347          * Bind us to CPU 0 so that all shutdown code runs there.  Some
  348          * systems don't shutdown properly (i.e., ACPI power off) if we
  349          * run on another processor.
  350          */
  351         if (!SCHEDULER_STOPPED()) {
  352                 thread_lock(curthread);
  353                 sched_bind(curthread, 0);
  354                 thread_unlock(curthread);
  355                 KASSERT(PCPU_GET(cpuid) == 0, ("boot: not running on cpu 0"));
  356         }
  357 #endif
  358         /* We're in the process of rebooting. */
  359         rebooting = 1;
  360 
  361         /* We are out of the debugger now. */
  362         kdb_active = 0;
  363 
  364         /*
  365          * Do any callouts that should be done BEFORE syncing the filesystems.
  366          */
  367         EVENTHANDLER_INVOKE(shutdown_pre_sync, howto);
  368 
  369         /* 
  370          * Now sync filesystems
  371          */
  372         if (!cold && (howto & RB_NOSYNC) == 0 && once == 0) {
  373                 once = 1;
  374                 bufshutdown(show_busybufs);
  375         }
  376 
  377         print_uptime();
  378 
  379         cngrab();
  380 
  381         /*
  382          * Ok, now do things that assume all filesystem activity has
  383          * been completed.
  384          */
  385         EVENTHANDLER_INVOKE(shutdown_post_sync, howto);
  386 
  387         if ((howto & (RB_HALT|RB_DUMP)) == RB_DUMP && !cold && !dumping) 
  388                 doadump(TRUE);
  389 
  390         /* Now that we're going to really halt the system... */
  391         EVENTHANDLER_INVOKE(shutdown_final, howto);
  392 
  393         for(;;) ;       /* safety against shutdown_reset not working */
  394         /* NOTREACHED */
  395 }
  396 
  397 /*
  398  * The system call that results in changing the rootfs.
  399  */
  400 static int
  401 kern_reroot(void)
  402 {
  403         struct vnode *oldrootvnode, *vp;
  404         struct mount *mp, *devmp;
  405         int error;
  406 
  407         if (curproc != initproc)
  408                 return (EPERM);
  409 
  410         /*
  411          * Mark the filesystem containing currently-running executable
  412          * (the temporary copy of init(8)) busy.
  413          */
  414         vp = curproc->p_textvp;
  415         error = vn_lock(vp, LK_SHARED);
  416         if (error != 0)
  417                 return (error);
  418         mp = vp->v_mount;
  419         error = vfs_busy(mp, MBF_NOWAIT);
  420         if (error != 0) {
  421                 vfs_ref(mp);
  422                 VOP_UNLOCK(vp, 0);
  423                 error = vfs_busy(mp, 0);
  424                 vn_lock(vp, LK_SHARED | LK_RETRY);
  425                 vfs_rel(mp);
  426                 if (error != 0) {
  427                         VOP_UNLOCK(vp, 0);
  428                         return (ENOENT);
  429                 }
  430                 if (vp->v_iflag & VI_DOOMED) {
  431                         VOP_UNLOCK(vp, 0);
  432                         vfs_unbusy(mp);
  433                         return (ENOENT);
  434                 }
  435         }
  436         VOP_UNLOCK(vp, 0);
  437 
  438         /*
  439          * Remove the filesystem containing currently-running executable
  440          * from the mount list, to prevent it from being unmounted
  441          * by vfs_unmountall(), and to avoid confusing vfs_mountroot().
  442          *
  443          * Also preserve /dev - forcibly unmounting it could cause driver
  444          * reinitialization.
  445          */
  446 
  447         vfs_ref(rootdevmp);
  448         devmp = rootdevmp;
  449         rootdevmp = NULL;
  450 
  451         mtx_lock(&mountlist_mtx);
  452         TAILQ_REMOVE(&mountlist, mp, mnt_list);
  453         TAILQ_REMOVE(&mountlist, devmp, mnt_list);
  454         mtx_unlock(&mountlist_mtx);
  455 
  456         oldrootvnode = rootvnode;
  457 
  458         /*
  459          * Unmount everything except for the two filesystems preserved above.
  460          */
  461         vfs_unmountall();
  462 
  463         /*
  464          * Add /dev back; vfs_mountroot() will move it into its new place.
  465          */
  466         mtx_lock(&mountlist_mtx);
  467         TAILQ_INSERT_HEAD(&mountlist, devmp, mnt_list);
  468         mtx_unlock(&mountlist_mtx);
  469         rootdevmp = devmp;
  470         vfs_rel(rootdevmp);
  471 
  472         /*
  473          * Mount the new rootfs.
  474          */
  475         vfs_mountroot();
  476 
  477         /*
  478          * Update all references to the old rootvnode.
  479          */
  480         mountcheckdirs(oldrootvnode, rootvnode);
  481 
  482         /*
  483          * Add the temporary filesystem back and unbusy it.
  484          */
  485         mtx_lock(&mountlist_mtx);
  486         TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
  487         mtx_unlock(&mountlist_mtx);
  488         vfs_unbusy(mp);
  489 
  490         return (0);
  491 }
  492 
  493 /*
  494  * If the shutdown was a clean halt, behave accordingly.
  495  */
  496 static void
  497 shutdown_halt(void *junk, int howto)
  498 {
  499 
  500         if (howto & RB_HALT) {
  501                 printf("\n");
  502                 printf("The operating system has halted.\n");
  503                 printf("Please press any key to reboot.\n\n");
  504 
  505                 wdog_kern_pat(WD_TO_NEVER);
  506 
  507                 switch (cngetc()) {
  508                 case -1:                /* No console, just die */
  509                         cpu_halt();
  510                         /* NOTREACHED */
  511                 default:
  512                         howto &= ~RB_HALT;
  513                         break;
  514                 }
  515         }
  516 }
  517 
  518 /*
  519  * Check to see if the system paniced, pause and then reboot
  520  * according to the specified delay.
  521  */
  522 static void
  523 shutdown_panic(void *junk, int howto)
  524 {
  525         int loop;
  526 
  527         if (howto & RB_DUMP) {
  528                 if (panic_reboot_wait_time != 0) {
  529                         if (panic_reboot_wait_time != -1) {
  530                                 printf("Automatic reboot in %d seconds - "
  531                                        "press a key on the console to abort\n",
  532                                         panic_reboot_wait_time);
  533                                 for (loop = panic_reboot_wait_time * 10;
  534                                      loop > 0; --loop) {
  535                                         DELAY(1000 * 100); /* 1/10th second */
  536                                         /* Did user type a key? */
  537                                         if (cncheckc() != -1)
  538                                                 break;
  539                                 }
  540                                 if (!loop)
  541                                         return;
  542                         }
  543                 } else { /* zero time specified - reboot NOW */
  544                         return;
  545                 }
  546                 printf("--> Press a key on the console to reboot,\n");
  547                 printf("--> or switch off the system now.\n");
  548                 cngetc();
  549         }
  550 }
  551 
  552 /*
  553  * Everything done, now reset
  554  */
  555 static void
  556 shutdown_reset(void *junk, int howto)
  557 {
  558 
  559         printf("Rebooting...\n");
  560         DELAY(1000000); /* wait 1 sec for printf's to complete and be read */
  561 
  562         /*
  563          * Acquiring smp_ipi_mtx here has a double effect:
  564          * - it disables interrupts avoiding CPU0 preemption
  565          *   by fast handlers (thus deadlocking  against other CPUs)
  566          * - it avoids deadlocks against smp_rendezvous() or, more 
  567          *   generally, threads busy-waiting, with this spinlock held,
  568          *   and waiting for responses by threads on other CPUs
  569          *   (ie. smp_tlb_shootdown()).
  570          *
  571          * For the !SMP case it just needs to handle the former problem.
  572          */
  573 #ifdef SMP
  574         mtx_lock_spin(&smp_ipi_mtx);
  575 #else
  576         spinlock_enter();
  577 #endif
  578 
  579         /* cpu_boot(howto); */ /* doesn't do anything at the moment */
  580         cpu_reset();
  581         /* NOTREACHED */ /* assuming reset worked */
  582 }
  583 
  584 #if defined(WITNESS) || defined(INVARIANT_SUPPORT)
  585 static int kassert_warn_only = 0;
  586 #ifdef KDB
  587 static int kassert_do_kdb = 0;
  588 #endif
  589 #ifdef KTR
  590 static int kassert_do_ktr = 0;
  591 #endif
  592 static int kassert_do_log = 1;
  593 static int kassert_log_pps_limit = 4;
  594 static int kassert_log_mute_at = 0;
  595 static int kassert_log_panic_at = 0;
  596 static int kassert_warnings = 0;
  597 
  598 SYSCTL_NODE(_debug, OID_AUTO, kassert, CTLFLAG_RW, NULL, "kassert options");
  599 
  600 SYSCTL_INT(_debug_kassert, OID_AUTO, warn_only, CTLFLAG_RWTUN,
  601     &kassert_warn_only, 0,
  602     "KASSERT triggers a panic (1) or just a warning (0)");
  603 
  604 #ifdef KDB
  605 SYSCTL_INT(_debug_kassert, OID_AUTO, do_kdb, CTLFLAG_RWTUN,
  606     &kassert_do_kdb, 0, "KASSERT will enter the debugger");
  607 #endif
  608 
  609 #ifdef KTR
  610 SYSCTL_UINT(_debug_kassert, OID_AUTO, do_ktr, CTLFLAG_RWTUN,
  611     &kassert_do_ktr, 0,
  612     "KASSERT does a KTR, set this to the KTRMASK you want");
  613 #endif
  614 
  615 SYSCTL_INT(_debug_kassert, OID_AUTO, do_log, CTLFLAG_RWTUN,
  616     &kassert_do_log, 0, "KASSERT triggers a panic (1) or just a warning (0)");
  617 
  618 SYSCTL_INT(_debug_kassert, OID_AUTO, warnings, CTLFLAG_RWTUN,
  619     &kassert_warnings, 0, "number of KASSERTs that have been triggered");
  620 
  621 SYSCTL_INT(_debug_kassert, OID_AUTO, log_panic_at, CTLFLAG_RWTUN,
  622     &kassert_log_panic_at, 0, "max number of KASSERTS before we will panic");
  623 
  624 SYSCTL_INT(_debug_kassert, OID_AUTO, log_pps_limit, CTLFLAG_RWTUN,
  625     &kassert_log_pps_limit, 0, "limit number of log messages per second");
  626 
  627 SYSCTL_INT(_debug_kassert, OID_AUTO, log_mute_at, CTLFLAG_RWTUN,
  628     &kassert_log_mute_at, 0, "max number of KASSERTS to log");
  629 
  630 static int kassert_sysctl_kassert(SYSCTL_HANDLER_ARGS);
  631 
  632 SYSCTL_PROC(_debug_kassert, OID_AUTO, kassert,
  633     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, NULL, 0,
  634     kassert_sysctl_kassert, "I", "set to trigger a test kassert");
  635 
  636 static int
  637 kassert_sysctl_kassert(SYSCTL_HANDLER_ARGS)
  638 {
  639         int error, i;
  640 
  641         error = sysctl_wire_old_buffer(req, sizeof(int));
  642         if (error == 0) {
  643                 i = 0;
  644                 error = sysctl_handle_int(oidp, &i, 0, req);
  645         }
  646         if (error != 0 || req->newptr == NULL)
  647                 return (error);
  648         KASSERT(0, ("kassert_sysctl_kassert triggered kassert %d", i));
  649         return (0);
  650 }
  651 
  652 /*
  653  * Called by KASSERT, this decides if we will panic
  654  * or if we will log via printf and/or ktr.
  655  */
  656 void
  657 kassert_panic(const char *fmt, ...)
  658 {
  659         static char buf[256];
  660         va_list ap;
  661 
  662         va_start(ap, fmt);
  663         (void)vsnprintf(buf, sizeof(buf), fmt, ap);
  664         va_end(ap);
  665 
  666         /*
  667          * panic if we're not just warning, or if we've exceeded
  668          * kassert_log_panic_at warnings.
  669          */
  670         if (!kassert_warn_only ||
  671             (kassert_log_panic_at > 0 &&
  672              kassert_warnings >= kassert_log_panic_at)) {
  673                 va_start(ap, fmt);
  674                 vpanic(fmt, ap);
  675                 /* NORETURN */
  676         }
  677 #ifdef KTR
  678         if (kassert_do_ktr)
  679                 CTR0(ktr_mask, buf);
  680 #endif /* KTR */
  681         /*
  682          * log if we've not yet met the mute limit.
  683          */
  684         if (kassert_do_log &&
  685             (kassert_log_mute_at == 0 ||
  686              kassert_warnings < kassert_log_mute_at)) {
  687                 static  struct timeval lasterr;
  688                 static  int curerr;
  689 
  690                 if (ppsratecheck(&lasterr, &curerr, kassert_log_pps_limit)) {
  691                         printf("KASSERT failed: %s\n", buf);
  692                         kdb_backtrace();
  693                 }
  694         }
  695 #ifdef KDB
  696         if (kassert_do_kdb) {
  697                 kdb_enter(KDB_WHY_KASSERT, buf);
  698         }
  699 #endif
  700         atomic_add_int(&kassert_warnings, 1);
  701 }
  702 #endif
  703 
  704 /*
  705  * Panic is called on unresolvable fatal errors.  It prints "panic: mesg",
  706  * and then reboots.  If we are called twice, then we avoid trying to sync
  707  * the disks as this often leads to recursive panics.
  708  */
  709 void
  710 panic(const char *fmt, ...)
  711 {
  712         va_list ap;
  713 
  714         va_start(ap, fmt);
  715         vpanic(fmt, ap);
  716 }
  717 
  718 void
  719 vpanic(const char *fmt, va_list ap)
  720 {
  721 #ifdef SMP
  722         cpuset_t other_cpus;
  723 #endif
  724         struct thread *td = curthread;
  725         int bootopt, newpanic;
  726         static char buf[256];
  727 
  728         spinlock_enter();
  729 
  730 #ifdef SMP
  731         /*
  732          * stop_cpus_hard(other_cpus) should prevent multiple CPUs from
  733          * concurrently entering panic.  Only the winner will proceed
  734          * further.
  735          */
  736         if (panicstr == NULL && !kdb_active) {
  737                 other_cpus = all_cpus;
  738                 CPU_CLR(PCPU_GET(cpuid), &other_cpus);
  739                 stop_cpus_hard(other_cpus);
  740         }
  741 #endif
  742 
  743         /*
  744          * Ensure that the scheduler is stopped while panicking, even if panic
  745          * has been entered from kdb.
  746          */
  747         td->td_stopsched = 1;
  748 
  749         bootopt = RB_AUTOBOOT;
  750         newpanic = 0;
  751         if (panicstr)
  752                 bootopt |= RB_NOSYNC;
  753         else {
  754                 bootopt |= RB_DUMP;
  755                 panicstr = fmt;
  756                 newpanic = 1;
  757         }
  758 
  759         if (newpanic) {
  760                 (void)vsnprintf(buf, sizeof(buf), fmt, ap);
  761                 panicstr = buf;
  762                 cngrab();
  763                 printf("panic: %s\n", buf);
  764         } else {
  765                 printf("panic: ");
  766                 vprintf(fmt, ap);
  767                 printf("\n");
  768         }
  769 #ifdef SMP
  770         printf("cpuid = %d\n", PCPU_GET(cpuid));
  771 #endif
  772 
  773 #ifdef KDB
  774         if (newpanic && trace_on_panic)
  775                 kdb_backtrace();
  776         if (debugger_on_panic)
  777                 kdb_enter(KDB_WHY_PANIC, "panic");
  778 #endif
  779         /*thread_lock(td); */
  780         td->td_flags |= TDF_INPANIC;
  781         /* thread_unlock(td); */
  782         if (!sync_on_panic)
  783                 bootopt |= RB_NOSYNC;
  784         kern_reboot(bootopt);
  785 }
  786 
  787 /*
  788  * Support for poweroff delay.
  789  *
  790  * Please note that setting this delay too short might power off your machine
  791  * before the write cache on your hard disk has been flushed, leading to
  792  * soft-updates inconsistencies.
  793  */
  794 #ifndef POWEROFF_DELAY
  795 # define POWEROFF_DELAY 5000
  796 #endif
  797 static int poweroff_delay = POWEROFF_DELAY;
  798 
  799 SYSCTL_INT(_kern_shutdown, OID_AUTO, poweroff_delay, CTLFLAG_RW,
  800     &poweroff_delay, 0, "Delay before poweroff to write disk caches (msec)");
  801 
  802 static void
  803 poweroff_wait(void *junk, int howto)
  804 {
  805 
  806         if (!(howto & RB_POWEROFF) || poweroff_delay <= 0)
  807                 return;
  808         DELAY(poweroff_delay * 1000);
  809 }
  810 
  811 /*
  812  * Some system processes (e.g. syncer) need to be stopped at appropriate
  813  * points in their main loops prior to a system shutdown, so that they
  814  * won't interfere with the shutdown process (e.g. by holding a disk buf
  815  * to cause sync to fail).  For each of these system processes, register
  816  * shutdown_kproc() as a handler for one of shutdown events.
  817  */
  818 static int kproc_shutdown_wait = 60;
  819 SYSCTL_INT(_kern_shutdown, OID_AUTO, kproc_shutdown_wait, CTLFLAG_RW,
  820     &kproc_shutdown_wait, 0, "Max wait time (sec) to stop for each process");
  821 
  822 void
  823 kproc_shutdown(void *arg, int howto)
  824 {
  825         struct proc *p;
  826         int error;
  827 
  828         if (panicstr)
  829                 return;
  830 
  831         p = (struct proc *)arg;
  832         printf("Waiting (max %d seconds) for system process `%s' to stop... ",
  833             kproc_shutdown_wait, p->p_comm);
  834         error = kproc_suspend(p, kproc_shutdown_wait * hz);
  835 
  836         if (error == EWOULDBLOCK)
  837                 printf("timed out\n");
  838         else
  839                 printf("done\n");
  840 }
  841 
  842 void
  843 kthread_shutdown(void *arg, int howto)
  844 {
  845         struct thread *td;
  846         int error;
  847 
  848         if (panicstr)
  849                 return;
  850 
  851         td = (struct thread *)arg;
  852         printf("Waiting (max %d seconds) for system thread `%s' to stop... ",
  853             kproc_shutdown_wait, td->td_name);
  854         error = kthread_suspend(td, kproc_shutdown_wait * hz);
  855 
  856         if (error == EWOULDBLOCK)
  857                 printf("timed out\n");
  858         else
  859                 printf("done\n");
  860 }
  861 
  862 static char dumpdevname[sizeof(((struct cdev*)NULL)->si_name)];
  863 SYSCTL_STRING(_kern_shutdown, OID_AUTO, dumpdevname, CTLFLAG_RD,
  864     dumpdevname, 0, "Device for kernel dumps");
  865 
  866 /* Registration of dumpers */
  867 int
  868 set_dumper(struct dumperinfo *di, const char *devname, struct thread *td)
  869 {
  870         size_t wantcopy;
  871         int error;
  872 
  873         error = priv_check(td, PRIV_SETDUMPER);
  874         if (error != 0)
  875                 return (error);
  876 
  877         if (di == NULL) {
  878                 if (dumper.blockbuf != NULL)
  879                         free(dumper.blockbuf, M_DUMPER);
  880                 bzero(&dumper, sizeof(dumper));
  881                 dumpdevname[0] = '\0';
  882                 return (0);
  883         }
  884         if (dumper.dumper != NULL)
  885                 return (EBUSY);
  886         dumper = *di;
  887         wantcopy = strlcpy(dumpdevname, devname, sizeof(dumpdevname));
  888         if (wantcopy >= sizeof(dumpdevname)) {
  889                 printf("set_dumper: device name truncated from '%s' -> '%s'\n",
  890                         devname, dumpdevname);
  891         }
  892         dumper.blockbuf = malloc(di->blocksize, M_DUMPER, M_WAITOK | M_ZERO);
  893         return (0);
  894 }
  895 
  896 /* Call dumper with bounds checking. */
  897 int
  898 dump_write(struct dumperinfo *di, void *virtual, vm_offset_t physical,
  899     off_t offset, size_t length)
  900 {
  901 
  902         if (length != 0 && (offset < di->mediaoffset ||
  903             offset - di->mediaoffset + length > di->mediasize)) {
  904                 printf("Attempt to write outside dump device boundaries.\n"
  905             "offset(%jd), mediaoffset(%jd), length(%ju), mediasize(%jd).\n",
  906                     (intmax_t)offset, (intmax_t)di->mediaoffset,
  907                     (uintmax_t)length, (intmax_t)di->mediasize);
  908                 return (ENOSPC);
  909         }
  910         return (di->dumper(di->priv, virtual, physical, offset, length));
  911 }
  912 
  913 /* Call dumper with bounds checking. */
  914 int
  915 dump_write_pad(struct dumperinfo *di, void *virtual, vm_offset_t physical,
  916     off_t offset, size_t length, size_t *size)
  917 {
  918         char *temp;
  919         int ret;
  920 
  921         if (length > di->blocksize)
  922                 return (ENOMEM);
  923 
  924         *size = di->blocksize;
  925         if (length == di->blocksize)
  926                 temp = virtual;
  927         else {
  928                 temp = di->blockbuf;
  929                 memset(temp + length, 0, di->blocksize - length);
  930                 memcpy(temp, virtual, length);
  931         }
  932         ret = dump_write(di, temp, physical, offset, *size);
  933 
  934         return (ret);
  935 }
  936 
  937 
  938 void
  939 mkdumpheader(struct kerneldumpheader *kdh, char *magic, uint32_t archver,
  940     uint64_t dumplen, uint32_t blksz)
  941 {
  942         size_t dstsize;
  943 
  944         bzero(kdh, sizeof(*kdh));
  945         strlcpy(kdh->magic, magic, sizeof(kdh->magic));
  946         strlcpy(kdh->architecture, MACHINE_ARCH, sizeof(kdh->architecture));
  947         kdh->version = htod32(KERNELDUMPVERSION);
  948         kdh->architectureversion = htod32(archver);
  949         kdh->dumplength = htod64(dumplen);
  950         kdh->dumptime = htod64(time_second);
  951         kdh->blocksize = htod32(blksz);
  952         strlcpy(kdh->hostname, prison0.pr_hostname, sizeof(kdh->hostname));
  953         dstsize = sizeof(kdh->versionstring);
  954         if (strlcpy(kdh->versionstring, version, dstsize) >= dstsize)
  955                 kdh->versionstring[dstsize - 2] = '\n';
  956         if (panicstr != NULL)
  957                 strlcpy(kdh->panicstring, panicstr, sizeof(kdh->panicstring));
  958         kdh->parity = kerneldump_parity(kdh);
  959 }
  960 
  961 #ifdef DDB
  962 DB_SHOW_COMMAND(panic, db_show_panic)
  963 {
  964 
  965         if (panicstr == NULL)
  966                 db_printf("panicstr not set\n");
  967         else
  968                 db_printf("panic: %s\n", panicstr);
  969 }
  970 #endif

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