kdumpd.tproj/kdumpd.c

   1 /*
   2  * Copyright (c) 1983, 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
  34 #include <sys/cdefs.h>
  35
  36 #ifndef lint
  37 __unused static const char copyright[] =
  38 "@(#) Copyright (c) 1983, 1993\n\
  39         The Regents of the University of California.  All rights reserved.\n";
  40 #endif /* not lint */
  41
  42 /* Mac OS X kernel core dump server, based on the BSD trivial file
  43  * transfer protocol server (FreeBSD distribution), with several
  44  * modifications. This server is *not* compatible with tftp, as the
  45  * protocol has changed considerably.
  46  */
  47
  48 /*
  49  * Based on the trivial file transfer protocol server.
  50  *
  51  * The original version included many modifications by Jim Guyton
  52  * <guyton@rand-unix>.
  53  */
  54
  55 #include <sys/param.h>
  56 #include <sys/ioctl.h>
  57 #include <sys/stat.h>
  58 #include <sys/socket.h>
  59 #include <sys/types.h>
  60 #include <sys/mman.h>
  61
  62 #include <netinet/in.h>
  63 #include "kdump.h"
  64 #include <arpa/inet.h>
  65
  66 #include <stdint.h>
  67 #include <ctype.h>
  68 #include <errno.h>
  69 #include <fcntl.h>
  70 #include <netdb.h>
  71 #include <pwd.h>
  72 #include <setjmp.h>
  73 #include <signal.h>
  74 #include <stdio.h>
  75 #include <stdlib.h>
  76 #include <string.h>
  77 #include <syslog.h>
  78 #include <unistd.h>
  79 #include <libkern/OSByteOrder.h>
  80
  81 #include "kdumpsubs.h"
  82
  83 #define TIMEOUT         2
  84
  85 int     peer;
  86 int     rexmtval = TIMEOUT;
  87 int     maxtimeout = 25 * TIMEOUT;
  88
  89 #define PKTSIZE SEGSIZE+6
  90
  91 char    buf[MAXIMUM_KDP_PKTSIZE];
  92 char    ackbuf[MAXIMUM_KDP_PKTSIZE];
  93 struct  sockaddr_in from;
  94 socklen_t fromlen;
  95
  96 void    kdump __P((struct kdumphdr *, int));
  97
  98 /*
  99  * Null-terminated directory prefix list for absolute pathname requests and
 100  * search list for relative pathname requests.
 101  *
 102  * MAXDIRS should be at least as large as the number of arguments that
 103  * inetd allows (currently 20).
 104  */
 105 #define MAXDIRS 20
 106 static struct dirlist {
 107         char    *name;
 108         int     len;
 109 } dirs[MAXDIRS+1];
 110 static int      suppress_naks;
 111 static int      logging = 1;
 112 static int      ipchroot;
 113
 114 static char *errtomsg __P((int));
 115 static void  nak __P((int));
 116 static char * __P(verifyhost(struct sockaddr_in *));
 117 uint32_t kdp_crashdump_pkt_size = (SEGSIZE + (sizeof(struct kdumphdr)));
 118 uint32_t kdp_crashdump_seg_size = SEGSIZE;
 119
 120 #define KDP_FEATURE_MASK_STRING         "features"
 121 enum    {KDP_FEATURE_LARGE_CRASHDUMPS = 1, KDP_FEATURE_LARGE_PKT_SIZE = 2};
 122
 123 uint32_t kdp_crashdump_feature_mask;
 124 uint32_t kdp_feature_large_crashdumps, kdp_feature_large_packets;
 125
 126 int
 127 main(argc, argv)
 128         int argc;
 129         char *argv[];
 130 {
 131         register struct kdumphdr *tp;
 132         register int n;
 133         int ch, on;
 134         struct sockaddr_in sin;
 135         char *chroot_dir = NULL;
 136         struct passwd *nobody;
 137         char *chuser = "nobody";
 138
 139         openlog("kdumpd", LOG_PID | LOG_NDELAY, LOG_FTP);
 140         while ((ch = getopt(argc, argv, "cClns:u:")) != -1) {
 141                 switch (ch) {
 142                 case 'c':
 143                         ipchroot = 1;
 144                         break;
 145                 case 'C':
 146                         ipchroot = 2;
 147                         break;
 148                 case 'l':
 149                         logging = 1;
 150                         break;
 151                 case 'n':
 152                         suppress_naks = 1;
 153                         break;
 154                 case 's':
 155                         chroot_dir = optarg;
 156                         break;
 157                 case 'u':
 158                         chuser = optarg;
 159                         break;
 160                 default:
 161                         syslog(LOG_WARNING, "ignoring unknown option -%c", ch);
 162                 }
 163         }
 164
 165         if (optind < argc) {
 166                 struct dirlist *dirp;
 167
 168                 /* Get list of directory prefixes. Skip relative pathnames. */
 169                 for (dirp = dirs; optind < argc && dirp < &dirs[MAXDIRS];
 170                      optind++) {
 171                         if (argv[optind][0] == '/') {
 172                                 dirp->name = argv[optind];
 173                                 dirp->len  = strlen(dirp->name);
 174                                 dirp++;
 175                         }
 176                 }
 177         }
 178         else if (chroot_dir) {
 179                 dirs->name = "/";
 180                 dirs->len = 1;
 181         }
 182         if (ipchroot && chroot_dir == NULL) {
 183                 syslog(LOG_ERR, "-c requires -s");
 184                 exit(1);
 185         }
 186
 187         on = 1;
 188         if (ioctl(0, FIONBIO, &on) < 0) {
 189                 syslog(LOG_ERR, "ioctl(FIONBIO): %m");
 190                 exit(1);
 191         }
 192         fromlen = sizeof (from);
 193         n = recvfrom(0, buf, sizeof (buf), 0,
 194             (struct sockaddr *)&from, &fromlen);
 195         if (n < 0) {
 196                 syslog(LOG_ERR, "recvfrom: %m");
 197                 exit(1);
 198         }
 199         /*
 200          * Now that we have read the message out of the UDP
 201          * socket, we fork and exit.  Thus, inetd will go back
 202          * to listening to the kdump port, and the next request
 203          * to come in will start up a new instance of kdumpd.
 204          *
 205          * We do this so that inetd can run kdumpd in "wait" mode.
 206          * The problem with kdumpd running in "nowait" mode is that
 207          * inetd may get one or more successful "selects" on the
 208          * kdump port before we do our receive, so more than one
 209          * instance of kdumpd may be started up.  Worse, if kdumpd
 210          * breaks before doing the above "recvfrom", inetd would
 211          * spawn endless instances, clogging the system.
 212          */
 213         {
 214                 int pid;
 215                 int i;
 216                 socklen_t j;
 217
 218                 for (i = 1; i < 20; i++) {
 219                     pid = fork();
 220                     if (pid < 0) {
 221                                 sleep(i);
 222                                 /*
 223                                  * flush out to most recently sent request.
 224                                  *
 225                                  * This may drop some requests, but those
 226                                  * will be resent by the clients when
 227                                  * they timeout.  The positive effect of
 228                                  * this flush is to (try to) prevent more
 229                                  * than one kdumpd being started up to service
 230                                  * a single request from a single client.
 231                                  */
 232                                 j = sizeof from;
 233                                 i = recvfrom(0, buf, sizeof (buf), 0,
 234                                     (struct sockaddr *)&from, &j);
 235                                 if (i > 0) {
 236                                         n = i;
 237                                         fromlen = j;
 238                                 }
 239                     } else {
 240                                 break;
 241                     }
 242                 }
 243                 if (pid < 0) {
 244                         syslog(LOG_ERR, "fork: %m");
 245                         exit(1);
 246                 } else if (pid != 0) {
 247                         exit(0);
 248                 }
 249         }
 250
 251         /*
 252          * Since we exit here, we should do that only after the above
 253          * recvfrom to keep inetd from constantly forking should there
 254          * be a problem.  See the above comment about system clogging.
 255          */
 256         if (chroot_dir) {
 257                 if (ipchroot) {
 258                         char tempchroot[MAXPATHLEN];
 259                         char *tempaddr;
 260                         struct stat sb;
 261                         int statret;
 262
 263                         tempaddr = inet_ntoa(from.sin_addr);
 264                         snprintf(tempchroot, sizeof(tempchroot), "%s/%s", chroot_dir, tempaddr);
 265                         statret = stat(tempchroot, &sb);
 266                         if (((sb.st_mode & S_IFMT ) == S_IFDIR) &&
 267                             (statret == 0 || (statret == -1 && ipchroot == 1)))
 268                                 chroot_dir = tempchroot;
 269                 }
 270                 /* Must get this before chroot because /etc might go away */
 271                 if ((nobody = getpwnam(chuser)) == NULL) {
 272                         syslog(LOG_ERR, "%s: no such user", chuser);
 273                         exit(1);
 274                 }
 275                 if (chroot(chroot_dir)) {
 276                         syslog(LOG_ERR, "chroot: %s: %m", chroot_dir);
 277                         exit(1);
 278                 }
 279                 chdir( "/" );
 280                 setuid(nobody->pw_uid);
 281         }
 282         else
 283           if (0 !=  chdir(dirs->name))
 284             syslog(LOG_ERR, "chdir%s: %m", dirs->name);
 285
 286         from.sin_family = AF_INET;
 287         alarm(0);
 288         close(0);
 289         close(1);
 290         peer = socket(AF_INET, SOCK_DGRAM, 0);
 291         if (peer < 0) {
 292                 syslog(LOG_ERR, "socket: %m");
 293                 exit(1);
 294         }
 295         memset(&sin, 0, sizeof(sin));
 296         sin.sin_family = AF_INET;
 297         if (bind(peer, (struct sockaddr *)&sin, sizeof (sin)) < 0) {
 298                 syslog(LOG_ERR, "bind: %m");
 299                 exit(1);
 300         }
 301         if (connect(peer, (struct sockaddr *)&from, sizeof(from)) < 0) {
 302                 syslog(LOG_ERR, "connect: %m");
 303                 exit(1);
 304         }
 305         tp = (struct kdumphdr *)buf;
 306         tp->th_opcode = ntohs(tp->th_opcode);
 307         if (tp->th_opcode == WRQ)
 308                 kdump(tp, n);
 309         exit(1);
 310 }
 311
 312 struct formats;
 313 int     validate_access __P((char **, int));
 314
 315 void    recvfile __P((struct formats *));
 316
 317 struct formats {
 318         char    *f_mode;
 319         int     (*f_validate) __P((char **, int));
 320
 321         void    (*f_recv) __P((struct formats *));
 322         int     f_convert;
 323 } formats[] = {
 324   { "netascii", validate_access, recvfile, 1 },
 325   { "octet",    validate_access, recvfile, 0 },
 326   { 0 }
 327 };
 328
 329 /*
 330  * Handle initial connection protocol.
 331  */
 332 void
 333 kdump(tp, size)
 334         struct kdumphdr *tp;
 335         int size;
 336 {
 337         register char *cp;
 338         int first = 1, ecode;
 339         register struct formats *pf;
 340         char *filename, *mode = NULL;
 341
 342         filename = cp = tp->th_stuff;
 343 again:
 344         while (cp < buf + size) {
 345                 if (*cp == '\0')
 346                         break;
 347                 cp++;
 348         }
 349         if (*cp != '\0') {
 350                 nak(EBADOP);
 351                 exit(1);
 352         }
 353         if (first) {
 354                 mode = ++cp;
 355                 first = 0;
 356                 goto again;
 357         }
 358         for (cp = mode; *cp; cp++)
 359                 if (isupper(*cp))
 360                         *cp = tolower(*cp);
 361
 362         cp++;
 363         if (strncmp(KDP_FEATURE_MASK_STRING, cp, sizeof(KDP_FEATURE_MASK_STRING)) == 0) {
 364                 kdp_crashdump_feature_mask = ntohl(*(uint32_t *) (cp + sizeof(KDP_FEATURE_MASK_STRING)));
 365                 kdp_feature_large_crashdumps = kdp_crashdump_feature_mask & KDP_FEATURE_LARGE_CRASHDUMPS;
 366                 kdp_feature_large_packets = kdp_crashdump_feature_mask & KDP_FEATURE_LARGE_PKT_SIZE;
 367
 368                 if (kdp_feature_large_packets) {
 369                         kdp_crashdump_pkt_size = KDP_LARGE_CRASHDUMP_PKT_SIZE;
 370                         kdp_crashdump_seg_size = kdp_crashdump_pkt_size - sizeof(struct kdumphdr);
 371                 }
 372                 syslog(KDUMPD_DEBUG_LEVEL, "Received feature mask %s:0x%x", cp, kdp_crashdump_feature_mask);
 373         } else
 374                 syslog(KDUMPD_DEBUG_LEVEL, "Unable to locate feature mask, mode: %s", mode);
 375
 376         for (pf = formats; pf->f_mode; pf++)
 377                 if (strcmp(pf->f_mode, mode) == 0)
 378                         break;
 379         if (pf->f_mode == 0) {
 380                 nak(EBADOP);
 381                 exit(1);
 382         }
 383         ecode = (*pf->f_validate)(&filename, tp->th_opcode);
 384         if (logging) {
 385                 syslog(KDUMPD_DEBUG_LEVEL, "%s: %s request for %s: %s", verifyhost(&from),
 386                         tp->th_opcode == WRQ ? "write" : "read",
 387                         filename, errtomsg(ecode));
 388         }
 389         if (ecode) {
 390                 /*
 391                  * Avoid storms of naks to a RRQ broadcast for a relative
 392                  * bootfile pathname from a diskless Sun.
 393                  */
 394                 if (suppress_naks && *filename != '/' && ecode == ENOTFOUND)
 395                         exit(0);
 396                 nak(ecode);
 397                 exit(1);
 398         }
 399         if (tp->th_opcode == WRQ)
 400                 (*pf->f_recv)(pf);
 401
 402         exit(0);
 403 }
 404
 405
 406 FILE *file;
 407
 408 /*
 409  * Validate file access. We only allow storage of files that do not already
 410  * exist, and that do not include directory specifiers in their pathnames.
 411  * This is because kernel coredump filenames should always be of the form
 412  * "core-version-IP as dotted quad-random string" as in :
 413  * core-custom-17.202.40.204-a75b4eec
 414  * The file is written to the directory supplied as the first argument
 415  * in inetd.conf
 416  */
 417
 418 int
 419 validate_access(char **filep, int mode)
 420 {
 421   struct stat stbuf;
 422   int   fd;
 423   char *filename = *filep;
 424   static char pathname[MAXPATHLEN];
 425
 426   if (strstr(filename, "/") || strstr(filename, ".."))
 427     return (EACCESS);
 428
 429   snprintf(pathname, sizeof(pathname), "./%s", filename);
 430
 431   if (0 == stat(pathname, &stbuf))
 432     return (EEXIST);
 433
 434   if (errno != ENOENT)
 435     return (errno);
 436
 437
 438   fd = open(filename, O_RDWR|O_CREAT|O_TRUNC , S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
 439
 440   if (fd < 0)
 441     return (errno + 100);
 442
 443   file = fdopen(fd, (mode == RRQ)? "r":"w");
 444   if (file == NULL) {
 445     return errno+100;
 446   }
 447
 448   return (0);
 449 }
 450
 451 int     timeout;
 452 jmp_buf timeoutbuf;
 453
 454 void
 455 timer()
 456 {
 457
 458         timeout += rexmtval;
 459         if (timeout >= maxtimeout)
 460           {
 461             longjmp(timeoutbuf, 2);
 462           }
 463         longjmp(timeoutbuf, 1);
 464 }
 465
 466 void
 467 justquit()
 468 {
 469         exit(0);
 470 }
 471
 472 /*
 473  * Receive a file.
 474  */
 475 void
 476 recvfile(pf)
 477         struct formats *pf;
 478 {
 479         struct kdumphdr *dp, *w_init();
 480         register struct kdumphdr *ap;    /* ack buffer */
 481         register int n, size;
 482         volatile unsigned int block;
 483         volatile unsigned int jmpval = 0;
 484
 485         signal(SIGALRM, timer);
 486         dp = w_init();
 487         ap = (struct kdumphdr *)ackbuf;
 488         block = 0;
 489         do {
 490 send_seek_ack:  timeout = 0;
 491                 if (block == 0)
 492                         ap->th_opcode = htons((u_short)ACK | ((kdp_feature_large_crashdumps | kdp_feature_large_packets)  << 8));
 493                 else
 494                         ap->th_opcode = htons((u_short)ACK);
 495                 ap->th_block = htonl((unsigned int)block);
 496                 block++;
 497                 jmpval = setjmp(timeoutbuf);
 498                 if (2 == jmpval)
 499                   {
 500                     syslog (LOG_ERR, "Timing out and flushing file to disk");
 501                     goto flushfile;
 502                   }
 503 send_ack:
 504                 if (send(peer, ackbuf, 6 , 0) != 6) {
 505                         syslog(LOG_ERR, "write: %m");
 506                         goto abort;
 507                 }
 508                 write_behind(file, pf->f_convert);
 509                 for ( ; ; ) {
 510                         alarm(rexmtval);
 511                         n = recv(peer, dp, kdp_crashdump_pkt_size, 0);
 512                         alarm(0);
 513                         if (n < 0) {            /* really? */
 514                                 syslog(LOG_ERR, "read: %m");
 515                                 goto abort;
 516                         }
 517                         dp->th_opcode = ntohs((u_short)dp->th_opcode);
 518                         dp->th_block = ntohl((unsigned int)dp->th_block);
 519 #if     DEBUG
 520                         syslog(KDUMPD_DEBUG_LEVEL, "Received packet type %u, block %u\n", (unsigned)dp->th_opcode, (unsigned)dp->th_block);
 521 #endif
 522
 523                         if (dp->th_opcode == ERROR)
 524                                 goto abort;
 525
 526                         if (dp->th_opcode == KDP_EOF)
 527                           {
 528                             syslog (LOG_ERR, "Received last panic dump packet");
 529                             goto final_ack;
 530                           }
 531                         if (dp->th_opcode == KDP_SEEK)
 532                           {
 533                             if (dp->th_block == block)
 534                               {
 535                                 off_t crashdump_offset = 0;
 536                                 unsigned int tempoff = 0;
 537
 538                                 if (kdp_feature_large_crashdumps) {
 539                                         crashdump_offset = OSSwapBigToHostInt64((*(uint64_t *)dp->th_data));
 540                                 }
 541                                 else {
 542                                 bcopy (dp->th_data, &tempoff, sizeof(unsigned int));
 543                                 crashdump_offset = ntohl(tempoff);
 544                                 }
 545
 546 #if     DEBUG
 547                                 syslog(KDUMPD_DEBUG_LEVEL, "Seeking to offset 0x%llx\n", crashdump_offset);
 548 #endif
 549                                 errno = 0;
 550                                 lseek(fileno (file), crashdump_offset, SEEK_SET);
 551                                 if (errno)
 552                                   syslog (LOG_ERR, "lseek: %m");
 553
 554                                 goto send_seek_ack;
 555                               }
 556                             (void) synchnet(peer);
 557                             if (dp->th_block == (block-1))
 558                             {
 559                                     syslog (LOG_DAEMON|LOG_ERR, "Retransmitting seek ack - current block %u, received block %u", block, dp->th_block);
 560                                     goto send_ack;          /* rexmit */
 561                             }
 562                         }
 563
 564                         if (dp->th_opcode == DATA) {
 565                                 if (dp->th_block == block) {
 566                                         break;   /* normal */
 567                                 }
 568                                 /* Re-synchronize with the other side */
 569                                 (void) synchnet(peer);
 570                                 if (dp->th_block == (block-1))
 571                                   {
 572                                     syslog (LOG_DAEMON|LOG_ERR, "Retransmitting ack - current block %u, received block %u", block, dp->th_block);
 573                                     goto send_ack;          /* rexmit */
 574                                   }
 575                                 else
 576                                   syslog (LOG_DAEMON|LOG_ERR, "Not retransmitting ack - current block %u, received block %u", block, dp->th_block);
 577                         }
 578                 }
 579 #if DEBUG
 580                 syslog(KDUMPD_DEBUG_LEVEL, "Writing block sized %u, current offset 0x%llx\n", n - 6, ftello(file));
 581 #endif
 582                 size = writeit(file, &dp, n - 6, pf->f_convert);
 583                 if (size != (n-6)) {                    /* ahem */
 584                         if (size < 0) nak(errno + 100);
 585                         else nak(ENOSPACE);
 586                         goto abort;
 587                 }
 588         } while (dp->th_opcode != KDP_EOF);
 589
 590 final_ack:
 591         ap->th_opcode = htons((u_short)ACK);    /* send the "final" ack */
 592         ap->th_block = htonl((unsigned int) (block));
 593         (void) send(peer, ackbuf, 6, 0);
 594 flushfile:
 595         write_behind(file, pf->f_convert);
 596         (void) fclose(file);            /* close data file */
 597         syslog (LOG_ERR, "file closed, sending final ACK\n");
 598
 599         signal(SIGALRM, justquit);      /* just quit on timeout */
 600         alarm(rexmtval);
 601         n = recv(peer, buf, sizeof (buf), 0); /* normally times out and quits */
 602         alarm(0);
 603         if (n >= 6 &&                   /* if read some data */
 604             dp->th_opcode == DATA &&    /* and got a data block */
 605             block == dp->th_block) {    /* then my last ack was lost */
 606                 (void) send(peer, ackbuf, 6, 0);     /* resend final ack */
 607         }
 608 abort:
 609         return;
 610 }
 611
 612 /* update if needed, when adding new errmsgs */
 613 #define MAXERRMSGLEN    40
 614
 615 struct errmsg {
 616         int     e_code;
 617         char    *e_msg;
 618 } errmsgs[] = {
 619         { EUNDEF,       "Undefined error code" },
 620         { ENOTFOUND,    "File not found" },
 621         { EACCESS,      "Access violation" },
 622         { ENOSPACE,     "Disk full or allocation exceeded" },
 623         { EBADOP,       "Illegal KDUMP operation" },
 624         { EBADID,       "Unknown transfer ID" },
 625         { EEXISTS,      "File already exists" },
 626         { ENOUSER,      "No such user" },
 627         { -1,           0 }
 628 };
 629
 630 static char *
 631 errtomsg(error)
 632         int error;
 633 {
 634         static char buf[20];
 635         register struct errmsg *pe;
 636         if (error == 0)
 637                 return "success";
 638         for (pe = errmsgs; pe->e_code >= 0; pe++)
 639                 if (pe->e_code == error)
 640                         return pe->e_msg;
 641         snprintf(buf, sizeof(buf), "error %d", error);
 642         return buf;
 643 }
 644
 645 /*
 646  * Send a nak packet (error message).
 647  * Error code passed in is one of the
 648  * standard KDUMP codes, or a UNIX errno
 649  * offset by 100.
 650  */
 651 static void
 652 nak(error)
 653         int error;
 654 {
 655         register struct kdumphdr *tp;
 656         int length;
 657         register struct errmsg *pe;
 658
 659         tp = (struct kdumphdr *)buf;
 660         tp->th_opcode = htons((u_short)ERROR);
 661         tp->th_code = htons((unsigned int)error);
 662         for (pe = errmsgs; pe->e_code >= 0; pe++)
 663                 if (pe->e_code == error)
 664                         break;
 665         if (pe->e_code < 0) {
 666                 pe->e_msg = strerror(error - 100);
 667                 tp->th_code = EUNDEF;   /* set 'undef' errorcode */
 668         }
 669         if (strlen(pe->e_msg) > MAXERRMSGLEN) {
 670                 syslog(LOG_ERR, "nak: error msg too long");
 671                 return;
 672         }
 673
 674         strlcpy(tp->th_msg, pe->e_msg, MAXERRMSGLEN);
 675         length = strlen(pe->e_msg);
 676         tp->th_msg[length] = '\0';
 677         length += 5;
 678         if (send(peer, buf, length, 0) != length)
 679                 syslog(LOG_ERR, "nak: %m");
 680
 681         return;
 682 }
 683
 684 static char *
 685 verifyhost(fromp)
 686         struct sockaddr_in *fromp;
 687 {
 688         struct hostent *hp;
 689
 690         hp = gethostbyaddr((char *)&fromp->sin_addr, sizeof(fromp->sin_addr),
 691                 fromp->sin_family);
 692         if(hp)
 693                 return hp->h_name;
 694         else
 695                 return inet_ntoa(fromp->sin_addr);
 696 }