sys/kern/kern_shutdown.c

   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  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *      This product includes software developed by the University of
  21  *      California, Berkeley and its contributors.
  22  * 4. Neither the name of the University nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  *
  38  *      @(#)kern_shutdown.c     8.3 (Berkeley) 1/21/94
  39  * $FreeBSD: src/sys/kern/kern_shutdown.c,v 1.72.2.12 2002/02/21 19:15:10 dillon Exp $
  40  * $DragonFly: src/sys/kern/kern_shutdown.c,v 1.62 2008/01/05 13:23:48 corecode Exp $
  41  */
  42
  43 #include "opt_ddb.h"
  44 #include "opt_ddb_trace.h"
  45 #include "opt_hw_wdog.h"
  46 #include "opt_panic.h"
  47 #include "opt_show_busybufs.h"
  48
  49 #include <sys/param.h>
  50 #include <sys/systm.h>
  51 #include <sys/eventhandler.h>
  52 #include <sys/buf.h>
  53 #include <sys/diskslice.h>
  54 #include <sys/reboot.h>
  55 #include <sys/proc.h>
  56 #include <sys/priv.h>
  57 #include <sys/fcntl.h>          /* FREAD        */
  58 #include <sys/stat.h>           /* S_IFCHR      */
  59 #include <sys/vnode.h>
  60 #include <sys/kernel.h>
  61 #include <sys/kthread.h>
  62 #include <sys/malloc.h>
  63 #include <sys/mount.h>
  64 #include <sys/queue.h>
  65 #include <sys/sysctl.h>
  66 #include <sys/vkernel.h>
  67 #include <sys/conf.h>
  68 #include <sys/sysproto.h>
  69 #include <sys/device.h>
  70 #include <sys/cons.h>
  71 #include <sys/shm.h>
  72 #include <sys/kern_syscall.h>
  73 #include <vm/vm_map.h>
  74 #include <vm/pmap.h>
  75
  76 #include <sys/thread2.h>
  77 #include <sys/buf2.h>
  78
  79 #include <machine/pcb.h>
  80 #include <machine/clock.h>
  81 #include <machine/md_var.h>
  82 #include <machine/smp.h>                /* smp_active_mask, cpuid */
  83 #include <machine/vmparam.h>
  84
  85 #include <sys/signalvar.h>
  86
  87 #ifndef PANIC_REBOOT_WAIT_TIME
  88 #define PANIC_REBOOT_WAIT_TIME 15 /* default to 15 seconds */
  89 #endif
  90
  91 /*
  92  * Note that stdarg.h and the ANSI style va_start macro is used for both
  93  * ANSI and traditional C compilers.  We use the machine version to stay
  94  * within the confines of the kernel header files.
  95  */
  96 #include <machine/stdarg.h>
  97
  98 #ifdef DDB
  99 #include <ddb/ddb.h>
 100 #ifdef DDB_UNATTENDED
 101 int debugger_on_panic = 0;
 102 #else
 103 int debugger_on_panic = 1;
 104 #endif
 105 SYSCTL_INT(_debug, OID_AUTO, debugger_on_panic, CTLFLAG_RW,
 106         &debugger_on_panic, 0, "Run debugger on kernel panic");
 107
 108 #ifdef DDB_TRACE
 109 int trace_on_panic = 1;
 110 #else
 111 int trace_on_panic = 0;
 112 #endif
 113 SYSCTL_INT(_debug, OID_AUTO, trace_on_panic, CTLFLAG_RW,
 114         &trace_on_panic, 0, "Print stack trace on kernel panic");
 115 #endif
 116
 117 static int sync_on_panic = 0;
 118 SYSCTL_INT(_kern, OID_AUTO, sync_on_panic, CTLFLAG_RW,
 119         &sync_on_panic, 0, "Do a sync before rebooting from a panic");
 120
 121 SYSCTL_NODE(_kern, OID_AUTO, shutdown, CTLFLAG_RW, 0, "Shutdown environment");
 122
 123 #ifdef  HW_WDOG
 124 /*
 125  * If there is a hardware watchdog, point this at the function needed to
 126  * hold it off.
 127  * It's needed when the kernel needs to do some lengthy operations.
 128  * e.g. in wd.c when dumping core.. It's most annoying to have
 129  * your precious core-dump only half written because the wdog kicked in.
 130  */
 131 watchdog_tickle_fn wdog_tickler = NULL;
 132 #endif  /* HW_WDOG */
 133
 134 /*
 135  * Variable panicstr contains argument to first call to panic; used as flag
 136  * to indicate that the kernel has already called panic.
 137  */
 138 const char *panicstr;
 139
 140 int dumping;                            /* system is dumping */
 141 #ifdef SMP
 142 u_int panic_cpu_interlock;              /* panic interlock */
 143 globaldata_t panic_cpu_gd;              /* which cpu took the panic */
 144 #endif
 145
 146 int bootverbose = 0;                    /* note: assignment to force non-bss */
 147 SYSCTL_INT(_debug, OID_AUTO, bootverbose, CTLFLAG_RW,
 148            &bootverbose, 0, "Verbose kernel messages");
 149
 150 int cold = 1;                           /* note: assignment to force non-bss */
 151 int dumplo;                             /* OBSOLETE - savecore compat */
 152 u_int64_t dumplo64;
 153
 154 static void boot (int) __dead2;
 155 static void dumpsys (void);
 156 static int setdumpdev (cdev_t dev);
 157 static void poweroff_wait (void *, int);
 158 static void print_uptime (void);
 159 static void shutdown_halt (void *junk, int howto);
 160 static void shutdown_panic (void *junk, int howto);
 161 static void shutdown_reset (void *junk, int howto);
 162 static int shutdown_busycount1(struct buf *bp, void *info);
 163 static int shutdown_busycount2(struct buf *bp, void *info);
 164 static void shutdown_cleanup_proc(struct proc *p);
 165
 166 /* register various local shutdown events */
 167 static void
 168 shutdown_conf(void *unused)
 169 {
 170         EVENTHANDLER_REGISTER(shutdown_final, poweroff_wait, NULL, SHUTDOWN_PRI_FIRST);
 171         EVENTHANDLER_REGISTER(shutdown_final, shutdown_halt, NULL, SHUTDOWN_PRI_LAST + 100);
 172         EVENTHANDLER_REGISTER(shutdown_final, shutdown_panic, NULL, SHUTDOWN_PRI_LAST + 100);
 173         EVENTHANDLER_REGISTER(shutdown_final, shutdown_reset, NULL, SHUTDOWN_PRI_LAST + 200);
 174 }
 175
 176 SYSINIT(shutdown_conf, SI_BOOT2_MACHDEP, SI_ORDER_ANY, shutdown_conf, NULL)
 177
 178 /* ARGSUSED */
 179
 180 /*
 181  * The system call that results in a reboot
 182  */
 183 int
 184 sys_reboot(struct reboot_args *uap)
 185 {
 186         struct thread *td = curthread;
 187         int error;
 188
 189         if ((error = priv_check(td, PRIV_REBOOT)))
 190                 return (error);
 191
 192         boot(uap->opt);
 193         return (0);
 194 }
 195
 196 /*
 197  * Called by events that want to shut down.. e.g  <CTL><ALT><DEL> on a PC
 198  */
 199 static int shutdown_howto = 0;
 200
 201 void
 202 shutdown_nice(int howto)
 203 {
 204         shutdown_howto = howto;
 205
 206         /* Send a signal to init(8) and have it shutdown the world */
 207         if (initproc != NULL) {
 208                 ksignal(initproc, SIGINT);
 209         } else {
 210                 /* No init(8) running, so simply reboot */
 211                 boot(RB_NOSYNC);
 212         }
 213         return;
 214 }
 215 static int      waittime = -1;
 216 static struct thread *dumpthread;
 217 static struct pcb dumppcb;
 218
 219 static void
 220 print_uptime(void)
 221 {
 222         int f;
 223         struct timespec ts;
 224
 225         getnanouptime(&ts);
 226         kprintf("Uptime: ");
 227         f = 0;
 228         if (ts.tv_sec >= 86400) {
 229                 kprintf("%ldd", ts.tv_sec / 86400);
 230                 ts.tv_sec %= 86400;
 231                 f = 1;
 232         }
 233         if (f || ts.tv_sec >= 3600) {
 234                 kprintf("%ldh", ts.tv_sec / 3600);
 235                 ts.tv_sec %= 3600;
 236                 f = 1;
 237         }
 238         if (f || ts.tv_sec >= 60) {
 239                 kprintf("%ldm", ts.tv_sec / 60);
 240                 ts.tv_sec %= 60;
 241                 f = 1;
 242         }
 243         kprintf("%lds\n", ts.tv_sec);
 244 }
 245
 246 /*
 247  *  Go through the rigmarole of shutting down..
 248  * this used to be in machdep.c but I'll be dammned if I could see
 249  * anything machine dependant in it.
 250  */
 251 static void
 252 boot(int howto)
 253 {
 254         /*
 255          * Get rid of any user scheduler baggage and then give
 256          * us a high priority.
 257          */
 258         if (curthread->td_release)
 259                 curthread->td_release(curthread);
 260         lwkt_setpri_self(TDPRI_MAX);
 261
 262         /* collect extra flags that shutdown_nice might have set */
 263         howto |= shutdown_howto;
 264
 265 #ifdef SMP
 266         /*
 267          * We really want to shutdown on the BSP.  Subsystems such as ACPI
 268          * can't power-down the box otherwise.
 269          */
 270         if (smp_active_mask > 1) {
 271                 kprintf("boot() called on cpu#%d\n", mycpu->gd_cpuid);
 272         }
 273         if (panicstr == NULL && mycpu->gd_cpuid != 0) {
 274                 kprintf("Switching to cpu #0 for shutdown\n");
 275                 lwkt_setcpu_self(globaldata_find(0));
 276         }
 277 #endif
 278         /*
 279          * Do any callouts that should be done BEFORE syncing the filesystems.
 280          */
 281         EVENTHANDLER_INVOKE(shutdown_pre_sync, howto);
 282
 283         /*
 284          * Try to get rid of any remaining FS references.  The calling
 285          * process, proc0, and init may still hold references.  The
 286          * VFS cache subsystem may still hold a root reference to root.
 287          *
 288          * XXX this needs work.  We really need to SIGSTOP all remaining
 289          * processes in order to avoid blowups due to proc0's filesystem
 290          * references going away.  For now just make sure that the init
 291          * process is stopped.
 292          */
 293         if (panicstr == NULL) {
 294                 shutdown_cleanup_proc(curproc);
 295                 shutdown_cleanup_proc(&proc0);
 296                 if (initproc) {
 297                         if (initproc != curproc) {
 298                                 ksignal(initproc, SIGSTOP);
 299                                 tsleep(boot, 0, "shutdn", hz / 20);
 300                         }
 301                         shutdown_cleanup_proc(initproc);
 302                 }
 303                 vfs_cache_setroot(NULL, NULL);
 304         }
 305
 306         /*
 307          * Now sync filesystems
 308          */
 309         if (!cold && (howto & RB_NOSYNC) == 0 && waittime < 0) {
 310                 int iter, nbusy, pbusy;
 311
 312                 waittime = 0;
 313                 kprintf("\nsyncing disks... ");
 314
 315                 sys_sync(NULL); /* YYY was sync(&proc0, NULL). why proc0 ? */
 316
 317                 /*
 318                  * With soft updates, some buffers that are
 319                  * written will be remarked as dirty until other
 320                  * buffers are written.
 321                  */
 322                 for (iter = pbusy = 0; iter < 20; iter++) {
 323                         nbusy = scan_all_buffers(shutdown_busycount1, NULL);
 324                         if (nbusy == 0)
 325                                 break;
 326                         kprintf("%d ", nbusy);
 327                         if (nbusy < pbusy)
 328                                 iter = 0;
 329                         pbusy = nbusy;
 330                         /*
 331                          * XXX:
 332                          * Process soft update work queue if buffers don't sync
 333                          * after 6 iterations by permitting the syncer to run.
 334                          */
 335                         if (iter > 5)
 336                                 bio_ops_sync(NULL);
 337
 338                         sys_sync(NULL); /* YYY was sync(&proc0, NULL). why proc0 ? */
 339                         tsleep(boot, 0, "shutdn", hz * iter / 20 + 1);
 340                 }
 341                 kprintf("\n");
 342                 /*
 343                  * Count only busy local buffers to prevent forcing
 344                  * a fsck if we're just a client of a wedged NFS server
 345                  */
 346                 nbusy = scan_all_buffers(shutdown_busycount2, NULL);
 347                 if (nbusy) {
 348                         /*
 349                          * Failed to sync all blocks. Indicate this and don't
 350                          * unmount filesystems (thus forcing an fsck on reboot).
 351                          */
 352                         kprintf("giving up on %d buffers\n", nbusy);
 353 #ifdef DDB
 354                         Debugger("busy buffer problem");
 355 #endif /* DDB */
 356                         tsleep(boot, 0, "shutdn", hz * 5 + 1);
 357                 } else {
 358                         kprintf("done\n");
 359                         /*
 360                          * Unmount filesystems
 361                          */
 362                         if (panicstr == NULL)
 363                                 vfs_unmountall();
 364                 }
 365                 tsleep(boot, 0, "shutdn", hz / 10 + 1);
 366         }
 367
 368         print_uptime();
 369
 370         /*
 371          * Dump before doing post_sync shutdown ops
 372          */
 373         crit_enter();
 374         if ((howto & (RB_HALT|RB_DUMP)) == RB_DUMP && !cold)
 375                 dumpsys();
 376
 377         /*
 378          * Ok, now do things that assume all filesystem activity has
 379          * been completed.  This will also call the device shutdown
 380          * methods.
 381          */
 382         EVENTHANDLER_INVOKE(shutdown_post_sync, howto);
 383
 384         /* Now that we're going to really halt the system... */
 385         EVENTHANDLER_INVOKE(shutdown_final, howto);
 386
 387         for(;;) ;       /* safety against shutdown_reset not working */
 388         /* NOTREACHED */
 389 }
 390
 391 static int
 392 shutdown_busycount1(struct buf *bp, void *info)
 393 {
 394         if ((bp->b_flags & B_INVAL) == 0 && BUF_REFCNT(bp) > 0)
 395                 return(1);
 396         if ((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI)
 397                 return (1);
 398         return (0);
 399 }
 400
 401 static int
 402 shutdown_busycount2(struct buf *bp, void *info)
 403 {
 404         if (((bp->b_flags & B_INVAL) == 0 && BUF_REFCNT(bp)) ||
 405             ((bp->b_flags & (B_DELWRI|B_INVAL)) == B_DELWRI)) {
 406                 /*
 407                  * Only count buffers undergoing write I/O
 408                  * on the related vnode.
 409                  */
 410                 if (bp->b_vp == NULL ||
 411                     bio_track_active(&bp->b_vp->v_track_write) == 0) {
 412                         return (0);
 413                 }
 414 #if defined(SHOW_BUSYBUFS) || defined(DIAGNOSTIC)
 415                 kprintf(
 416             "%p dev:?, flags:%08x, loffset:%lld, doffset:%lld\n",
 417                     bp,
 418                     bp->b_flags, bp->b_loffset,
 419                     bp->b_bio2.bio_offset);
 420 #endif
 421                 return(1);
 422         }
 423         return(0);
 424 }
 425
 426 /*
 427  * If the shutdown was a clean halt, behave accordingly.
 428  */
 429 static void
 430 shutdown_halt(void *junk, int howto)
 431 {
 432         if (howto & RB_HALT) {
 433                 kprintf("\n");
 434                 kprintf("The operating system has halted.\n");
 435 #ifdef _KERNEL_VIRTUAL
 436                 cpu_halt();
 437 #else
 438                 kprintf("Please press any key to reboot.\n\n");
 439                 switch (cngetc()) {
 440                 case -1:                /* No console, just die */
 441                         cpu_halt();
 442                         /* NOTREACHED */
 443                 default:
 444                         howto &= ~RB_HALT;
 445                         break;
 446                 }
 447 #endif
 448         }
 449 }
 450
 451 /*
 452  * Check to see if the system paniced, pause and then reboot
 453  * according to the specified delay.
 454  */
 455 static void
 456 shutdown_panic(void *junk, int howto)
 457 {
 458         int loop;
 459
 460         if (howto & RB_DUMP) {
 461                 if (PANIC_REBOOT_WAIT_TIME != 0) {
 462                         if (PANIC_REBOOT_WAIT_TIME != -1) {
 463                                 kprintf("Automatic reboot in %d seconds - "
 464                                        "press a key on the console to abort\n",
 465                                         PANIC_REBOOT_WAIT_TIME);
 466                                 for (loop = PANIC_REBOOT_WAIT_TIME * 10;
 467                                      loop > 0; --loop) {
 468                                         DELAY(1000 * 100); /* 1/10th second */
 469                                         /* Did user type a key? */
 470                                         if (cncheckc() != -1)
 471                                                 break;
 472                                 }
 473                                 if (!loop)
 474                                         return;
 475                         }
 476                 } else { /* zero time specified - reboot NOW */
 477                         return;
 478                 }
 479                 kprintf("--> Press a key on the console to reboot,\n");
 480                 kprintf("--> or switch off the system now.\n");
 481                 cngetc();
 482         }
 483 }
 484
 485 /*
 486  * Everything done, now reset
 487  */
 488 static void
 489 shutdown_reset(void *junk, int howto)
 490 {
 491         kprintf("Rebooting...\n");
 492         DELAY(1000000); /* wait 1 sec for kprintf's to complete and be read */
 493         /* cpu_boot(howto); */ /* doesn't do anything at the moment */
 494         cpu_reset();
 495         /* NOTREACHED */ /* assuming reset worked */
 496 }
 497
 498 /*
 499  * Try to remove FS references in the specified process.  This function
 500  * is used during shutdown
 501  */
 502 static
 503 void
 504 shutdown_cleanup_proc(struct proc *p)
 505 {
 506         struct filedesc *fdp;
 507         struct vmspace *vm;
 508
 509         if (p == NULL)
 510                 return;
 511         if ((fdp = p->p_fd) != NULL) {
 512                 kern_closefrom(0);
 513                 if (fdp->fd_cdir) {
 514                         cache_drop(&fdp->fd_ncdir);
 515                         vrele(fdp->fd_cdir);
 516                         fdp->fd_cdir = NULL;
 517                 }
 518                 if (fdp->fd_rdir) {
 519                         cache_drop(&fdp->fd_nrdir);
 520                         vrele(fdp->fd_rdir);
 521                         fdp->fd_rdir = NULL;
 522                 }
 523                 if (fdp->fd_jdir) {
 524                         cache_drop(&fdp->fd_njdir);
 525                         vrele(fdp->fd_jdir);
 526                         fdp->fd_jdir = NULL;
 527                 }
 528         }
 529         if (p->p_vkernel)
 530                 vkernel_exit(p);
 531         if (p->p_textvp) {
 532                 vrele(p->p_textvp);
 533                 p->p_textvp = NULL;
 534         }
 535         vm = p->p_vmspace;
 536         if (vm != NULL) {
 537                 pmap_remove_pages(vmspace_pmap(vm),
 538                                   VM_MIN_USER_ADDRESS,
 539                                   VM_MAX_USER_ADDRESS);
 540                 vm_map_remove(&vm->vm_map,
 541                               VM_MIN_USER_ADDRESS,
 542                               VM_MAX_USER_ADDRESS);
 543         }
 544 }
 545
 546 /*
 547  * Magic number for savecore
 548  *
 549  * exported (symorder) and used at least by savecore(8)
 550  *
 551  * Mark it as used so that gcc doesn't optimize it away.
 552  */
 553 __attribute__((__used__))
 554         static u_long const dumpmag = 0x8fca0101UL;
 555
 556 static int      dumpsize = 0;           /* also for savecore */
 557
 558 static int      dodump = 1;
 559
 560 SYSCTL_INT(_machdep, OID_AUTO, do_dump, CTLFLAG_RW, &dodump, 0,
 561     "Try to perform coredump on kernel panic");
 562
 563 static int
 564 setdumpdev(cdev_t dev)
 565 {
 566         struct partinfo pinfo;
 567         u_int64_t newdumplo;
 568         int error;
 569         int doopen;
 570
 571         if (dev == NULL) {
 572                 dumpdev = dev;
 573                 return (0);
 574         }
 575         bzero(&pinfo, sizeof(pinfo));
 576
 577         /*
 578          * We have to open the device before we can perform ioctls on it,
 579          * or the slice/label data may not be present.  Device opens are
 580          * usually tracked by specfs, but the dump device can be set in
 581          * early boot and may not be open so this is somewhat of a hack.
 582          */
 583         doopen = (dev->si_sysref.refcnt == 1);
 584         if (doopen) {
 585                 error = dev_dopen(dev, FREAD, S_IFCHR, proc0.p_ucred);
 586                 if (error)
 587                         return (error);
 588         }
 589         error = dev_dioctl(dev, DIOCGPART, (void *)&pinfo, 0,
 590                            proc0.p_ucred, NULL);
 591         if (doopen)
 592                 dev_dclose(dev, FREAD, S_IFCHR);
 593         if (error || pinfo.media_blocks == 0 || pinfo.media_blksize == 0)
 594                 return (ENXIO);
 595
 596         newdumplo = pinfo.media_blocks -
 597                     ((u_int64_t)Maxmem * PAGE_SIZE / DEV_BSIZE);
 598         if ((int64_t)newdumplo < (int64_t)pinfo.reserved_blocks)
 599                 return (ENOSPC);
 600         dumpdev = dev;
 601         dumplo64 = newdumplo;
 602         return (0);
 603 }
 604
 605
 606 /* ARGSUSED */
 607 static void dump_conf (void *dummy);
 608 static void
 609 dump_conf(void *dummy)
 610 {
 611         char *path;
 612         cdev_t dev;
 613
 614         path = kmalloc(MNAMELEN, M_TEMP, M_WAITOK);
 615         if (TUNABLE_STR_FETCH("dumpdev", path, MNAMELEN) != 0) {
 616                 dev = kgetdiskbyname(path);
 617                 if (dev != NULL)
 618                         dumpdev = dev;
 619         }
 620         kfree(path, M_TEMP);
 621         if (setdumpdev(dumpdev) != 0)
 622                 dumpdev = NULL;
 623 }
 624
 625 SYSINIT(dump_conf, SI_SUB_DUMP_CONF, SI_ORDER_FIRST, dump_conf, NULL)
 626
 627 static int
 628 sysctl_kern_dumpdev(SYSCTL_HANDLER_ARGS)
 629 {
 630         int error;
 631         udev_t ndumpdev;
 632
 633         ndumpdev = dev2udev(dumpdev);
 634         error = sysctl_handle_opaque(oidp, &ndumpdev, sizeof ndumpdev, req);
 635         if (error == 0 && req->newptr != NULL)
 636                 error = setdumpdev(udev2dev(ndumpdev, 0));
 637         return (error);
 638 }
 639
 640 SYSCTL_PROC(_kern, KERN_DUMPDEV, dumpdev, CTLTYPE_OPAQUE|CTLFLAG_RW,
 641         0, sizeof dumpdev, sysctl_kern_dumpdev, "T,udev_t", "");
 642
 643 /*
 644  * Doadump comes here after turning off memory management and
 645  * getting on the dump stack, either when called above, or by
 646  * the auto-restart code.
 647  */
 648 static void
 649 dumpsys(void)
 650 {
 651         int     error;
 652
 653         savectx(&dumppcb);
 654         dumpthread = curthread;
 655         if (dumping++) {
 656                 kprintf("Dump already in progress, bailing...\n");
 657                 return;
 658         }
 659         if (!dodump)
 660                 return;
 661         if (dumpdev == NULL)
 662                 return;
 663         dumpsize = Maxmem;
 664         kprintf("\ndumping to dev %s, blockno %lld\n",
 665                 devtoname(dumpdev),
 666                 (long long)dumplo64);
 667         kprintf("dump ");
 668         error = dev_ddump(dumpdev);
 669         if (error == 0) {
 670                 kprintf("succeeded\n");
 671                 return;
 672         }
 673         kprintf("failed, reason: ");
 674         switch (error) {
 675         case ENOSYS:
 676         case ENODEV:
 677                 kprintf("device doesn't support a dump routine\n");
 678                 break;
 679
 680         case ENXIO:
 681                 kprintf("device bad\n");
 682                 break;
 683
 684         case EFAULT:
 685                 kprintf("device not ready\n");
 686                 break;
 687
 688         case EINVAL:
 689                 kprintf("area improper\n");
 690                 break;
 691
 692         case EIO:
 693                 kprintf("i/o error\n");
 694                 break;
 695
 696         case EINTR:
 697                 kprintf("aborted from console\n");
 698                 break;
 699
 700         default:
 701                 kprintf("unknown, error = %d\n", error);
 702                 break;
 703         }
 704 }
 705
 706 int
 707 dumpstatus(vm_offset_t addr, off_t count)
 708 {
 709         int c;
 710
 711         if (addr % (1024 * 1024) == 0) {
 712 #ifdef HW_WDOG
 713                 if (wdog_tickler)
 714                         (*wdog_tickler)();
 715 #endif
 716                 kprintf("%ld ", (long)(count / (1024 * 1024)));
 717         }
 718
 719         if ((c = cncheckc()) == 0x03)
 720                 return -1;
 721         else if (c != -1)
 722                 kprintf("[CTRL-C to abort] ");
 723
 724         return 0;
 725 }
 726
 727 /*
 728  * Panic is called on unresolvable fatal errors.  It prints "panic: mesg",
 729  * and then reboots.  If we are called twice, then we avoid trying to sync
 730  * the disks as this often leads to recursive panics.
 731  */
 732 void
 733 panic(const char *fmt, ...)
 734 {
 735         int bootopt, newpanic;
 736         __va_list ap;
 737         static char buf[256];
 738
 739 #ifdef SMP
 740         /*
 741          * If a panic occurs on multiple cpus before the first is able to
 742          * halt the other cpus, only one cpu is allowed to take the panic.
 743          * Attempt to be verbose about this situation but if the kprintf()
 744          * itself panics don't let us overrun the kernel stack.
 745          *
 746          * Be very nasty about descheduling our thread at the lowest
 747          * level possible in an attempt to freeze the thread without
 748          * inducing further panics.
 749          *
 750          * Bumping gd_trap_nesting_level will also bypass assertions in
 751          * lwkt_switch() and allow us to switch away even if we are a
 752          * FAST interrupt or IPI.
 753          */
 754         if (atomic_poll_acquire_int(&panic_cpu_interlock)) {
 755                 panic_cpu_gd = mycpu;
 756         } else if (panic_cpu_gd != mycpu) {
 757                 crit_enter();
 758                 ++mycpu->gd_trap_nesting_level;
 759                 if (mycpu->gd_trap_nesting_level < 25) {
 760                         kprintf("SECONDARY PANIC ON CPU %d THREAD %p\n",
 761                                 mycpu->gd_cpuid, curthread);
 762                 }
 763                 curthread->td_release = NULL;   /* be a grinch */
 764                 for (;;) {
 765                         lwkt_deschedule_self(curthread);
 766                         lwkt_switch();
 767                 }
 768                 /* NOT REACHED */
 769                 /* --mycpu->gd_trap_nesting_level */
 770                 /* crit_exit() */
 771         }
 772 #endif
 773         bootopt = RB_AUTOBOOT | RB_DUMP;
 774         if (sync_on_panic == 0)
 775                 bootopt |= RB_NOSYNC;
 776         newpanic = 0;
 777         if (panicstr)
 778                 bootopt |= RB_NOSYNC;
 779         else {
 780                 panicstr = fmt;
 781                 newpanic = 1;
 782         }
 783
 784         __va_start(ap, fmt);
 785         kvsnprintf(buf, sizeof(buf), fmt, ap);
 786         if (panicstr == fmt)
 787                 panicstr = buf;
 788         __va_end(ap);
 789         kprintf("panic: %s\n", buf);
 790 #ifdef SMP
 791         /* two separate prints in case of an unmapped page and trap */
 792         kprintf("mp_lock = %08x; ", mp_lock);
 793         kprintf("cpuid = %d\n", mycpu->gd_cpuid);
 794 #endif
 795
 796 #if defined(DDB)
 797         if (newpanic && trace_on_panic)
 798                 print_backtrace();
 799         if (debugger_on_panic)
 800                 Debugger("panic");
 801 #endif
 802         boot(bootopt);
 803 }
 804
 805 /*
 806  * Support for poweroff delay.
 807  */
 808 #ifndef POWEROFF_DELAY
 809 # define POWEROFF_DELAY 5000
 810 #endif
 811 static int poweroff_delay = POWEROFF_DELAY;
 812
 813 SYSCTL_INT(_kern_shutdown, OID_AUTO, poweroff_delay, CTLFLAG_RW,
 814         &poweroff_delay, 0, "");
 815
 816 static void
 817 poweroff_wait(void *junk, int howto)
 818 {
 819         if(!(howto & RB_POWEROFF) || poweroff_delay <= 0)
 820                 return;
 821         DELAY(poweroff_delay * 1000);
 822 }
 823
 824 /*
 825  * Some system processes (e.g. syncer) need to be stopped at appropriate
 826  * points in their main loops prior to a system shutdown, so that they
 827  * won't interfere with the shutdown process (e.g. by holding a disk buf
 828  * to cause sync to fail).  For each of these system processes, register
 829  * shutdown_kproc() as a handler for one of shutdown events.
 830  */
 831 static int kproc_shutdown_wait = 60;
 832 SYSCTL_INT(_kern_shutdown, OID_AUTO, kproc_shutdown_wait, CTLFLAG_RW,
 833     &kproc_shutdown_wait, 0, "");
 834
 835 void
 836 shutdown_kproc(void *arg, int howto)
 837 {
 838         struct thread *td;
 839         struct proc *p;
 840         int error;
 841
 842         if (panicstr)
 843                 return;
 844
 845         td = (struct thread *)arg;
 846         if ((p = td->td_proc) != NULL) {
 847             kprintf("Waiting (max %d seconds) for system process `%s' to stop...",
 848                 kproc_shutdown_wait, p->p_comm);
 849         } else {
 850             kprintf("Waiting (max %d seconds) for system thread %s to stop...",
 851                 kproc_shutdown_wait, td->td_comm);
 852         }
 853         error = suspend_kproc(td, kproc_shutdown_wait * hz);
 854
 855         if (error == EWOULDBLOCK)
 856                 kprintf("timed out\n");
 857         else
 858                 kprintf("stopped\n");
 859 }