sbin/savecore/savecore.c

   1 /*-
   2  * Copyright (c) 1986, 1992, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  * @(#) Copyright (c) 1986, 1992, 1993 The Regents of the University of California.  All rights reserved.
  34  * @(#)savecore.c       8.3 (Berkeley) 1/2/94
  35  * $FreeBSD: src/sbin/savecore/savecore.c,v 1.28.2.14 2005/01/05 09:14:34 maxim Exp $
  36  * $DragonFly: src/sbin/savecore/savecore.c,v 1.15 2007/05/19 06:54:29 dillon Exp $
  37  */
  38
  39 #define _KERNEL_STRUCTURES
  40
  41 #include <sys/param.h>
  42
  43 #undef _KERNEL_STRUCTURES
  44
  45 #include <sys/stat.h>
  46 #include <sys/mount.h>
  47 #include <sys/syslog.h>
  48 #include <sys/sysctl.h>
  49
  50 #include <vm/vm.h>
  51 #include <vm/vm_param.h>
  52 #include <vm/pmap.h>
  53
  54 #include <dirent.h>
  55 #include <fcntl.h>
  56 #include <nlist.h>
  57 #include <paths.h>
  58 #include <stdio.h>
  59 #include <stdlib.h>
  60 #include <string.h>
  61 #include <unistd.h>
  62 #include <err.h>
  63
  64 extern FILE *zopen(const char *fname, const char *mode);
  65
  66 #define ok(number) ((number) - kernbase)
  67
  68 struct nlist current_nl[] = {   /* Namelist for currently running system. */
  69 #define X_DUMPLO        0
  70         { "_dumplo64", 0, 0, 0, 0 },
  71 #define X_TIME          1
  72         { "_time_second", 0, 0, 0, 0 },
  73 #define X_DUMPSIZE      2
  74         { "_dumpsize", 0, 0, 0, 0 },
  75 #define X_VERSION       3
  76         { "_version", 0, 0, 0, 0 },
  77 #define X_PANICSTR      4
  78         { "_panicstr", 0, 0, 0, 0 },
  79 #define X_DUMPMAG       5
  80         { "_dumpmag", 0, 0, 0, 0 },
  81 #define X_KERNBASE      6
  82         { "_kernbase", 0, 0, 0, 0 },
  83 #define X_MAXMEM        7
  84         { "_Maxmem", 0, 0, 0, 0 },
  85         { "", 0, 0, 0, 0 },
  86 };
  87 int cursyms[] = { X_DUMPLO, X_VERSION, X_DUMPMAG, -1 };
  88 int dumpsyms[] = { X_TIME, X_DUMPSIZE, X_VERSION, X_PANICSTR, X_DUMPMAG, -1 };
  89
  90 struct nlist dump_nl[] = {               /* Name list for dumped system. */
  91         { "_dumplo64", 0, 0, 0, 0 },     /* Entries MUST be the same as  */
  92         { "_time_second", 0, 0, 0, 0 },  /* those in current_nl[].       */
  93         { "_dumpsize", 0, 0, 0, 0 },
  94         { "_version", 0, 0, 0, 0 },
  95         { "_panicstr", 0, 0, 0, 0 },
  96         { "_dumpmag", 0, 0, 0, 0 },
  97         { "_kernbase", 0, 0, 0, 0 },
  98         { "_Maxmem", 0, 0, 0, 0 },
  99         { "", 0, 0, 0, 0 },
 100 };
 101
 102 /* Types match kernel declarations. */
 103 u_long  dumpmag;                        /* magic number in dump */
 104
 105 /* Based on kernel variables, but with more convenient types. */
 106 off_t   dumplo;                         /* where dump starts on dumpdev */
 107 off_t   dumpsize;                       /* amount of memory dumped */
 108
 109 char    *kernel;                        /* user-specified kernel */
 110 char    *savedir;                       /* directory to save dumps in */
 111 char    ddname[MAXPATHLEN];             /* name of dump device */
 112 dev_t   dumpdev;                        /* dump device */
 113 int     dumpfd;                         /* read/write descriptor on char dev */
 114 time_t  now;                            /* current date */
 115 char    panic_mesg[1024];               /* panic message */
 116 int     panicstr;                       /* flag: dump was caused by panic */
 117 char    vers[1024];                     /* version of kernel that crashed */
 118 char    *physmem;                       /* physmem value used with dumped session */
 119 u_int64_t dkdumplo;                     /* directly specified kernel dumplo value */
 120
 121 u_long  kernbase;                       /* offset of kvm to core file */
 122
 123 static int      clear, compress, force, verbose, directdumplo;  /* flags */
 124 static int      keep;                   /* keep dump on device */
 125
 126 static void     check_kmem(void);
 127 static int      check_space(void);
 128 static void     clear_dump(void);
 129 static void     DumpRead(int fd, void *bp, int size, off_t off, int flag);
 130 static void     DumpWrite(int fd, void *bp, int size, off_t off, int flag);
 131 static int      dump_exists(void);
 132 static void     find_dev(dev_t);
 133 static int      get_crashtime(void);
 134 static void     get_dumpsize(void);
 135 static void     kmem_setup(void);
 136 static void     Lseek(int, off_t, int);
 137 static int      Open(const char *, int rw);
 138 static int      Read(int, void *, int);
 139 static void     save_core(void);
 140 static void     usage(void);
 141 static int      verify_dev(char *, dev_t);
 142 static void     Write(int, void *, int);
 143 static void     kdumplo_adjust(char *cp, int kmem, u_int64_t *kdumplop);
 144
 145 int
 146 main(int argc, char **argv)
 147 {
 148         int ch;
 149         char *ep;
 150
 151         openlog("savecore", LOG_PERROR, LOG_DAEMON);
 152
 153         while ((ch = getopt(argc, argv, "cD:dfkN:vzP:B:")) != -1)
 154                 switch(ch) {
 155                 case 'c':
 156                         clear = 1;
 157                         break;
 158                 case 'D':
 159                         strncpy(ddname, optarg, sizeof(ddname));
 160                         break;
 161                 case 'd':               /* Not documented. */
 162                 case 'v':
 163                         verbose = 1;
 164                         break;
 165                 case 'f':
 166                         force = 1;
 167                         break;
 168                 case 'k':
 169                         keep = 1;
 170                         break;
 171                 case 'N':
 172                         kernel = optarg;
 173                         break;
 174                 case 'z':
 175                         compress = 1;
 176                         break;
 177                 case 'P':
 178                         physmem = optarg;
 179                         break;
 180                 case 'B':
 181                         directdumplo = 1;
 182                         dkdumplo = strtouq(optarg, &ep, 10);
 183                         if (*ep != '\0')
 184                                 errx(1, "invalid offset: '%s'", optarg);
 185                         break;
 186                 case '?':
 187                 default:
 188                         usage();
 189                 }
 190         argc -= optind;
 191         argv += optind;
 192
 193         if (!clear) {
 194                 if (argc != 1 && argc != 2)
 195                         usage();
 196                 savedir = argv[0];
 197         }
 198         if (argc == 2)
 199                 kernel = argv[1];
 200
 201         time(&now);
 202         kmem_setup();
 203
 204         if (clear) {
 205                 clear_dump();
 206                 exit(0);
 207         }
 208
 209         if (!dump_exists() && !force)
 210                 exit(1);
 211
 212         check_kmem();
 213
 214         if (panicstr)
 215                 syslog(LOG_ALERT, "reboot after panic: %s", panic_mesg);
 216         else
 217                 syslog(LOG_ALERT, "reboot");
 218
 219         get_dumpsize();
 220
 221         if ((!get_crashtime() || !check_space()) && !force)
 222                 exit(1);
 223
 224         save_core();
 225
 226         if (!keep)
 227                 clear_dump();
 228
 229         exit(0);
 230 }
 231
 232 static void
 233 kmem_setup(void)
 234 {
 235         int kmem, i;
 236         const char *dump_sys;
 237         size_t len;
 238         u_int64_t kdumplo;      /* block number where dump starts on dumpdev */
 239         char *p;
 240
 241         /*
 242          * Some names we need for the currently running system, others for
 243          * the system that was running when the dump was made.  The values
 244          * obtained from the current system are used to look for things in
 245          * /dev/kmem that cannot be found in the dump_sys namelist, but are
 246          * presumed to be the same (since the disk partitions are probably
 247          * the same!)
 248          */
 249         if ((nlist(getbootfile(), current_nl)) == -1)
 250                 syslog(LOG_ERR, "%s: nlist: %m", getbootfile());
 251         for (i = 0; cursyms[i] != -1; i++)
 252                 if (current_nl[cursyms[i]].n_value == 0) {
 253                         syslog(LOG_ERR, "%s: %s not in namelist",
 254                             getbootfile(), current_nl[cursyms[i]].n_name);
 255                         exit(1);
 256                 }
 257
 258         dump_sys = kernel ? kernel : getbootfile();
 259         if ((nlist(dump_sys, dump_nl)) == -1)
 260                 syslog(LOG_ERR, "%s: nlist: %m", dump_sys);
 261         for (i = 0; dumpsyms[i] != -1; i++)
 262                 if (dump_nl[dumpsyms[i]].n_value == 0) {
 263                         syslog(LOG_ERR, "%s: %s not in namelist",
 264                             dump_sys, dump_nl[dumpsyms[i]].n_name);
 265                         exit(1);
 266                 }
 267
 268         if (dump_nl[X_KERNBASE].n_value != 0)
 269                 kernbase = dump_nl[X_KERNBASE].n_value;
 270         else
 271                 kernbase = KERNBASE;
 272
 273         if (*ddname == 0) {
 274                 len = sizeof dumpdev;
 275                 if (sysctlbyname("kern.dumpdev", &dumpdev, &len, NULL, 0) == -1) {
 276                         syslog(LOG_ERR, "sysctl: kern.dumpdev: %m");
 277                         exit(1);
 278                 }
 279                 if (dumpdev == NODEV) {
 280                         syslog(LOG_WARNING, "no core dump (no dumpdev)");
 281                         exit(1);
 282                 }
 283                 find_dev(dumpdev);
 284         }
 285
 286         kmem = Open(_PATH_KMEM, O_RDONLY);
 287         if (directdumplo) {
 288                 kdumplo = dkdumplo;
 289         } else {
 290                 Lseek(kmem, (off_t)current_nl[X_DUMPLO].n_value, L_SET);
 291                 Read(kmem, &kdumplo, sizeof(kdumplo));
 292                 if (physmem)
 293                         kdumplo_adjust(physmem, kmem, &kdumplo);
 294         }
 295                 dumplo = kdumplo * DEV_BSIZE;
 296         if (verbose)
 297                 printf("dumplo = %lld (%lld * %d)\n",
 298                     (long long)dumplo, kdumplo, DEV_BSIZE);
 299         Lseek(kmem, (off_t)current_nl[X_DUMPMAG].n_value, L_SET);
 300         Read(kmem, &dumpmag, sizeof(dumpmag));
 301         dumpfd = Open(ddname, O_RDWR);
 302         if (kernel)
 303                 return;
 304
 305         lseek(kmem, (off_t)current_nl[X_VERSION].n_value, SEEK_SET);
 306         Read(kmem, vers, sizeof(vers));
 307         vers[sizeof(vers) - 1] = '\0';
 308         p = strchr(vers, '\n');
 309         if (p)
 310                 p[1] = '\0';
 311
 312         /* Don't fclose(fp), we use kmem later. */
 313 }
 314
 315 static void
 316 check_kmem(void)
 317 {
 318         char core_vers[1024], *p;
 319
 320         DumpRead(dumpfd, core_vers, sizeof(core_vers),
 321             (off_t)(dumplo + ok(dump_nl[X_VERSION].n_value)), L_SET);
 322         core_vers[sizeof(core_vers) - 1] = '\0';
 323         p = strchr(core_vers, '\n');
 324         if (p)
 325                 p[1] = '\0';
 326         if (strcmp(vers, core_vers) && kernel == 0)
 327                 syslog(LOG_WARNING,
 328                     "warning: %s version mismatch:\n\t\"%s\"\nand\t\"%s\"\n",
 329                     getbootfile(), vers, core_vers);
 330         DumpRead(dumpfd, &panicstr, sizeof(panicstr),
 331             (off_t)(dumplo + ok(dump_nl[X_PANICSTR].n_value)), L_SET);
 332         if (panicstr) {
 333                 DumpRead(dumpfd, panic_mesg, sizeof(panic_mesg),
 334                     (off_t)(dumplo + ok(panicstr)), L_SET);
 335         }
 336 }
 337
 338 /*
 339  * Clear the magic number in the dump header.
 340  */
 341 static void
 342 clear_dump(void)
 343 {
 344         u_long newdumpmag;
 345
 346         newdumpmag = 0;
 347         DumpWrite(dumpfd, &newdumpmag, sizeof(newdumpmag),
 348             (off_t)(dumplo + ok(dump_nl[X_DUMPMAG].n_value)), L_SET);
 349         close(dumpfd);
 350 }
 351
 352 /*
 353  * Check if a dump exists by looking for a magic number in the dump
 354  * header.
 355  */
 356 static int
 357 dump_exists(void)
 358 {
 359         u_long newdumpmag;
 360
 361         DumpRead(dumpfd, &newdumpmag, sizeof(newdumpmag),
 362             (off_t)(dumplo + ok(dump_nl[X_DUMPMAG].n_value)), L_SET);
 363         if (newdumpmag != dumpmag) {
 364                 if (verbose)
 365                         syslog(LOG_WARNING, "magic number mismatch (%lx != %lx)",
 366                             newdumpmag, dumpmag);
 367                 syslog(LOG_WARNING, "no core dump");
 368                 return (0);
 369         }
 370         return (1);
 371 }
 372
 373 char buf[1024 * 1024];
 374 #define BLOCKSIZE (1<<12)
 375 #define BLOCKMASK (~(BLOCKSIZE-1))
 376
 377 /*
 378  * Save the core dump.
 379  */
 380 static void
 381 save_core(void)
 382 {
 383         FILE *fp;
 384         int bounds, ifd, nr, nw;
 385         int hs, he = 0;         /* start and end of hole */
 386         char path[MAXPATHLEN];
 387         mode_t oumask;
 388
 389         /*
 390          * Get the current number and update the bounds file.  Do the update
 391          * now, because may fail later and don't want to overwrite anything.
 392          */
 393         snprintf(path, sizeof(path), "%s/bounds", savedir);
 394         if ((fp = fopen(path, "r")) == NULL)
 395                 goto err1;
 396         if (fgets(buf, sizeof(buf), fp) == NULL) {
 397                 if (ferror(fp))
 398 err1:                   syslog(LOG_WARNING, "%s: %m", path);
 399                 bounds = 0;
 400         } else
 401                 bounds = atoi(buf);
 402         if (fp != NULL)
 403                 fclose(fp);
 404         if ((fp = fopen(path, "w")) == NULL)
 405                 syslog(LOG_ERR, "%s: %m", path);
 406         else {
 407                 fprintf(fp, "%d\n", bounds + 1);
 408                 fclose(fp);
 409         }
 410
 411         /* Create the core file. */
 412         oumask = umask(S_IRWXG|S_IRWXO); /* Restrict access to the core file.*/
 413         snprintf(path, sizeof(path), "%s/vmcore.%d%s",
 414             savedir, bounds, compress ? ".gz" : "");
 415         if (compress)
 416                 fp = zopen(path, "w");
 417         else
 418                 fp = fopen(path, "w");
 419         if (fp == NULL) {
 420                 syslog(LOG_ERR, "%s: %m", path);
 421                 exit(1);
 422         }
 423         umask(oumask);
 424
 425         /* Seek to the start of the core. */
 426         Lseek(dumpfd, (off_t)dumplo, L_SET);
 427
 428         /* Copy the core file. */
 429         syslog(LOG_NOTICE, "writing %score to %s",
 430             compress ? "compressed " : "", path);
 431         for (; dumpsize > 0; dumpsize -= nr) {
 432                 printf("%6ldK\r", (long)(dumpsize / 1024));
 433                 fflush(stdout);
 434                 nr = read(dumpfd, buf, MIN(dumpsize, sizeof(buf)));
 435                 if (nr <= 0) {
 436                         if (nr == 0)
 437                                 syslog(LOG_WARNING,
 438                                     "WARNING: EOF on dump device");
 439                         else
 440                                 syslog(LOG_ERR, "%s: %m", ddname);
 441                         goto err2;
 442                 }
 443                 if (compress) {
 444                         nw = fwrite(buf, 1, nr, fp);
 445                 } else {
 446                 for (nw = 0; nw < nr; nw = he) {
 447                         /* find a contiguous block of zeroes */
 448                         for (hs = nw; hs < nr; hs += BLOCKSIZE) {
 449                                 for (he = hs; he < nr && buf[he] == 0; ++he)
 450                                         /* nothing */ ;
 451
 452                                 /* is the hole long enough to matter? */
 453                                 if (he >= hs + BLOCKSIZE)
 454                                         break;
 455                         }
 456
 457                         /* back down to a block boundary */
 458                         he &= BLOCKMASK;
 459
 460                         /*
 461                          * 1) Don't go beyond the end of the buffer.
 462                          * 2) If the end of the buffer is less than
 463                          *    BLOCKSIZE bytes away, we're at the end
 464                          *    of the file, so just grab what's left.
 465                          */
 466                         if (hs + BLOCKSIZE > nr)
 467                                 hs = he = nr;
 468
 469                         /*
 470                          * At this point, we have a partial ordering:
 471                          *     nw <= hs <= he <= nr
 472                          * If hs > nw, buf[nw..hs] contains non-zero data.
 473                          * If he > hs, buf[hs..he] is all zeroes.
 474                          */
 475                         if (hs > nw)
 476                                 if (fwrite(buf + nw, hs - nw, 1, fp) != 1)
 477                                         break;
 478                         if (he > hs)
 479                                 if (fseeko(fp, he - hs, SEEK_CUR) == -1)
 480                                         break;
 481                         }
 482                 }
 483                 if (nw != nr) {
 484                         syslog(LOG_ERR, "%s: %m", path);
 485 err2:                   syslog(LOG_WARNING,
 486                             "WARNING: vmcore may be incomplete");
 487                         printf("\n");
 488                         exit(1);
 489                 }
 490         }
 491
 492         fclose(fp);
 493
 494         /* Copy the kernel. */
 495         ifd = Open(kernel ? kernel : getbootfile(), O_RDONLY);
 496         snprintf(path, sizeof(path), "%s/kernel.%d%s",
 497             savedir, bounds, compress ? ".gz" : "");
 498         if (compress)
 499                 fp = zopen(path, "w");
 500         else
 501                 fp = fopen(path, "w");
 502         if (fp == NULL) {
 503                 syslog(LOG_ERR, "%s: %m", path);
 504                 exit(1);
 505         }
 506         syslog(LOG_NOTICE, "writing %skernel to %s",
 507             compress ? "compressed " : "", path);
 508         while ((nr = read(ifd, buf, sizeof(buf))) > 0) {
 509                 nw = fwrite(buf, 1, nr, fp);
 510                 if (nw != nr) {
 511                         syslog(LOG_ERR, "%s: %m", path);
 512                         syslog(LOG_WARNING,
 513                             "WARNING: kernel may be incomplete");
 514                         exit(1);
 515                 }
 516         }
 517         if (nr < 0) {
 518                 syslog(LOG_ERR, "%s: %m", kernel ? kernel : getbootfile());
 519                 syslog(LOG_WARNING,
 520                     "WARNING: kernel may be incomplete");
 521                 exit(1);
 522         }
 523         fclose(fp);
 524         close(ifd);
 525 }
 526
 527 /*
 528  * Verify that the specified device node exists and matches the
 529  * specified device.
 530  */
 531 static int
 532 verify_dev(char *name, dev_t dev)
 533 {
 534         struct stat sb;
 535
 536         if (lstat(name, &sb) == -1)
 537                 return (-1);
 538         if (!S_ISCHR(sb.st_mode) || sb.st_rdev != dev)
 539                 return (-1);
 540         return (0);
 541 }
 542
 543 /*
 544  * Find the dump device.
 545  *
 546  *  1) try devname(3); see if it returns something sensible
 547  *  2) scan /dev for the desired node
 548  *  3) as a last resort, try to create the node we need
 549  */
 550 static void
 551 find_dev(dev_t dev)
 552 {
 553         struct dirent *ent;
 554         char *dn, *dnp;
 555         DIR *d;
 556
 557         strcpy(ddname, _PATH_DEV);
 558         dnp = ddname + sizeof _PATH_DEV - 1;
 559         if ((dn = devname(dev, S_IFCHR)) != NULL) {
 560                 strcpy(dnp, dn);
 561                 if (verify_dev(ddname, dev) == 0)
 562                         return;
 563         }
 564         if ((d = opendir(_PATH_DEV)) != NULL) {
 565                 while ((ent = readdir(d))) {
 566                         strcpy(dnp, ent->d_name);
 567                         if (verify_dev(ddname, dev) == 0) {
 568                                 closedir(d);
 569                                 return;
 570                         }
 571                 }
 572                 closedir(d);
 573         }
 574         strcpy(dnp, "dump");
 575         if (mknod(ddname, S_IFCHR|S_IRUSR|S_IWUSR, dev) == 0)
 576                 return;
 577         syslog(LOG_ERR, "can't find device %d/%#x", major(dev), minor(dev));
 578         exit(1);
 579 }
 580
 581 /*
 582  * Extract the date and time of the crash from the dump header, and
 583  * make sure it looks sane (within one week of current date and time).
 584  */
 585 static int
 586 get_crashtime(void)
 587 {
 588         time_t dumptime;                        /* Time the dump was taken. */
 589
 590         DumpRead(dumpfd, &dumptime, sizeof(dumptime),
 591             (off_t)(dumplo + ok(dump_nl[X_TIME].n_value)), L_SET);
 592         if (dumptime == 0) {
 593                 if (verbose)
 594                         syslog(LOG_ERR, "dump time is zero");
 595                 return (0);
 596         }
 597         printf("savecore: system went down at %s", ctime(&dumptime));
 598 #define LEEWAY  (7 * 86400)
 599         if (dumptime < now - LEEWAY || dumptime > now + LEEWAY) {
 600                 printf("dump time is unreasonable\n");
 601                 return (0);
 602         }
 603         return (1);
 604 }
 605
 606 /*
 607  * Extract the size of the dump from the dump header.
 608  */
 609 static void
 610 get_dumpsize(void)
 611 {
 612         int kdumpsize;  /* Number of pages in dump. */
 613
 614         /* Read the dump size. */
 615         DumpRead(dumpfd, &kdumpsize, sizeof(kdumpsize),
 616             (off_t)(dumplo + ok(dump_nl[X_DUMPSIZE].n_value)), L_SET);
 617         dumpsize = (off_t)kdumpsize * getpagesize();
 618 }
 619
 620 /*
 621  * Check that sufficient space is available on the disk that holds the
 622  * save directory.
 623  */
 624 static int
 625 check_space(void)
 626 {
 627         FILE *fp;
 628         const char *tkernel;
 629         off_t minfree, spacefree, totfree, kernelsize, needed;
 630         struct stat st;
 631         struct statfs fsbuf;
 632         char mybuf[100], path[MAXPATHLEN];
 633
 634         tkernel = kernel ? kernel : getbootfile();
 635         if (stat(tkernel, &st) < 0) {
 636                 syslog(LOG_ERR, "%s: %m", tkernel);
 637                 exit(1);
 638         }
 639         kernelsize = st.st_blocks * S_BLKSIZE;
 640
 641         if (statfs(savedir, &fsbuf) < 0) {
 642                 syslog(LOG_ERR, "%s: %m", savedir);
 643                 exit(1);
 644         }
 645         spacefree = ((off_t) fsbuf.f_bavail * fsbuf.f_bsize) / 1024;
 646         totfree = ((off_t) fsbuf.f_bfree * fsbuf.f_bsize) / 1024;
 647
 648         snprintf(path, sizeof(path), "%s/minfree", savedir);
 649         if ((fp = fopen(path, "r")) == NULL)
 650                 minfree = 0;
 651         else {
 652                 if (fgets(mybuf, sizeof(mybuf), fp) == NULL)
 653                         minfree = 0;
 654                 else
 655                         minfree = atoi(mybuf);
 656                 fclose(fp);
 657         }
 658
 659         needed = (dumpsize + kernelsize) / 1024;
 660         if (((minfree > 0) ? spacefree : totfree) - needed < minfree) {
 661                 syslog(LOG_WARNING,
 662         "no dump, not enough free space on device (%lld available, need %lld)",
 663                     (long long)(minfree > 0 ? spacefree : totfree),
 664                     (long long)needed);
 665                 return (0);
 666         }
 667         if (spacefree - needed < 0)
 668                 syslog(LOG_WARNING,
 669                     "dump performed, but free space threshold crossed");
 670         return (1);
 671 }
 672
 673 static int
 674 Open(const char *name, int rw)
 675 {
 676         int fd;
 677
 678         if ((fd = open(name, rw, 0)) < 0) {
 679                 syslog(LOG_ERR, "%s: %m", name);
 680                 exit(1);
 681         }
 682         return (fd);
 683 }
 684
 685 static int
 686 Read(int fd, void *bp, int size)
 687 {
 688         int nr;
 689
 690         nr = read(fd, bp, size);
 691         if (nr != size) {
 692                 syslog(LOG_ERR, "read: %m");
 693                 exit(1);
 694         }
 695         return (nr);
 696 }
 697
 698 static void
 699 Lseek(int fd, off_t off, int flag)
 700 {
 701         off_t ret;
 702
 703         ret = lseek(fd, off, flag);
 704         if (ret == -1) {
 705                 syslog(LOG_ERR, "lseek: %m");
 706                 exit(1);
 707         }
 708 }
 709
 710 /*
 711  * DumpWrite and DumpRead block io requests to the * dump device.
 712  */
 713 #define DUMPBUFSIZE     8192
 714 static void
 715 DumpWrite(int fd, void *bp, int size, off_t off, int flag)
 716 {
 717         unsigned char mybuf[DUMPBUFSIZE], *p, *q;
 718         off_t pos;
 719         int i, j;
 720
 721         if (flag != L_SET) {
 722                 syslog(LOG_ERR, "lseek: not LSET");
 723                 exit(2);
 724         }
 725         q = bp;
 726         while (size) {
 727                 pos = off & ~(DUMPBUFSIZE - 1);
 728                 Lseek(fd, pos, flag);
 729                 Read(fd, mybuf, sizeof(mybuf));
 730                 j = off & (DUMPBUFSIZE - 1);
 731                 p = mybuf + j;
 732                 i = size;
 733                 if (i > DUMPBUFSIZE - j)
 734                         i = DUMPBUFSIZE - j;
 735                 memcpy(p, q, i);
 736                 Lseek(fd, pos, flag);
 737                 Write(fd, mybuf, sizeof(mybuf));
 738                 size -= i;
 739                 q += i;
 740                 off += i;
 741         }
 742 }
 743
 744 static void
 745 DumpRead(int fd, void *bp, int size, off_t off, int flag)
 746 {
 747         unsigned char mybuf[DUMPBUFSIZE], *p, *q;
 748         off_t pos;
 749         int i, j;
 750
 751         if (flag != L_SET) {
 752                 syslog(LOG_ERR, "lseek: not LSET");
 753                 exit(2);
 754         }
 755         q = bp;
 756         while (size) {
 757                 pos = off & ~(DUMPBUFSIZE - 1);
 758                 Lseek(fd, pos, flag);
 759                 Read(fd, mybuf, sizeof(mybuf));
 760                 j = off & (DUMPBUFSIZE - 1);
 761                 p = mybuf + j;
 762                 i = size;
 763                 if (i > DUMPBUFSIZE - j)
 764                         i = DUMPBUFSIZE - j;
 765                 memcpy(q, p, i);
 766                 size -= i;
 767                 q += i;
 768                 off += i;
 769         }
 770 }
 771
 772 static void
 773 Write(int fd, void *bp, int size)
 774 {
 775         int n;
 776
 777         if ((n = write(fd, bp, size)) < size) {
 778                 syslog(LOG_ERR, "write: %m");
 779                 exit(1);
 780         }
 781 }
 782
 783 static void
 784 kdumplo_adjust(char *cp, int kmem, u_int64_t *kdumplop)
 785 {
 786         uint64_t AllowMem, sanity, Maxmem, CurrMaxmem;
 787         char *ep;
 788
 789         /* based on getmemsize() in i386/i386/machdep.c */
 790         sanity = AllowMem = strtouq(cp, &ep, 0);
 791         if ((ep != cp) && (*ep != 0)) {
 792                 switch(*ep) {
 793                 case 'g':
 794                 case 'G':
 795                         AllowMem <<= 10;
 796                 case 'm':
 797                 case 'M':
 798                         AllowMem <<= 10;
 799                 case 'k':
 800                 case 'K':
 801                         AllowMem <<= 10;
 802                         break;
 803                 default:
 804                         AllowMem = 0;
 805                 }
 806                 if (AllowMem < sanity)
 807                         AllowMem = 0;
 808         }
 809         if (AllowMem == 0)
 810                 errx(1, "invalid memory size: '%s'\n", cp);
 811         else
 812                 Maxmem = atop(AllowMem);
 813
 814         Lseek(kmem, (off_t)current_nl[X_MAXMEM].n_value, L_SET);
 815         Read(kmem, &CurrMaxmem, sizeof(CurrMaxmem));
 816
 817         /* based on setdumpdev() in kern_shutdown.c */
 818         *kdumplop += (u_int64_t)CurrMaxmem * PAGE_SIZE / DEV_BSIZE;
 819         *kdumplop -= (u_int64_t)Maxmem * PAGE_SIZE / DEV_BSIZE;
 820 }
 821
 822 static void
 823 usage(void)
 824 {
 825         syslog(LOG_ERR,
 826                "usage: savecore [-cfkvz] [-N system] [-P physmem|-B blkno] directory");
 827         exit(1);
 828 }