network_cmds/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 <assert.h>
  67 #include <stdint.h>
  68 #include <ctype.h>
  69 #include <errno.h>
  70 #include <fcntl.h>
  71 #include <netdb.h>
  72 #include <pwd.h>
  73 #include <setjmp.h>
  74 #include <signal.h>
  75 #include <stdio.h>
  76 #include <stdlib.h>
  77 #include <string.h>
  78 #include <syslog.h>
  79 #include <unistd.h>
  80 #include <libkern/OSByteOrder.h>
  81
  82 #include "kdumpsubs.h"
  83
  84 #define DEFAULT_KDUMPD_PORTNO (1069)
  85 #define TIMEOUT         2
  86
  87 int     peer;
  88 int     rexmtval = TIMEOUT;
  89 int     maxtimeout = 25 * TIMEOUT;
  90
  91 #define PKTSIZE SEGSIZE+6
  92
  93 char    buf[MAXIMUM_KDP_PKTSIZE];
  94 char    ackbuf[MAXIMUM_KDP_PKTSIZE];
  95 struct  sockaddr_in from;
  96 socklen_t fromlen;
  97
  98 void    kdump __P((struct kdumphdr *, int));
  99
 100 /*
 101  * Null-terminated directory prefix list for absolute pathname requests and
 102  * search list for relative pathname requests.
 103  *
 104  * MAXDIRS should be at least as large as the number of arguments that
 105  * inetd allows (currently 20).
 106  */
 107 #define MAXDIRS 20
 108 static struct dirlist {
 109         char    *name;
 110         int     len;
 111 } dirs[MAXDIRS+1];
 112 static int      suppress_naks;
 113 static int      logging = 1;
 114 static int      ipchroot;
 115 static int  server_mode = 1;
 116
 117 static char *errtomsg __P((int));
 118 static void  nak __P((int));
 119 static char * __P(verifyhost(struct sockaddr_in *));
 120 uint32_t kdp_crashdump_pkt_size = (SEGSIZE + (sizeof(struct kdumphdr)));
 121 uint32_t kdp_crashdump_seg_size = SEGSIZE;
 122
 123 #define KDP_FEATURE_MASK_STRING         "features"
 124 enum    {KDP_FEATURE_LARGE_CRASHDUMPS = 1, KDP_FEATURE_LARGE_PKT_SIZE = 2};
 125
 126 uint32_t kdp_crashdump_feature_mask;
 127 uint32_t kdp_feature_large_crashdumps, kdp_feature_large_packets;
 128
 129 int
 130 main(argc, argv)
 131         int argc;
 132         char *argv[];
 133 {
 134         register struct kdumphdr *tp;
 135         register int n;
 136         int ch, on;
 137         struct sockaddr_in sin;
 138         char *chroot_dir = NULL;
 139         struct passwd *nobody;
 140         char *chuser = "nobody";
 141
 142         openlog("kdumpd", LOG_PID | LOG_NDELAY, LOG_FTP);
 143         while ((ch = getopt(argc, argv, "cClns:u:w")) != -1) {
 144                 switch (ch) {
 145                 case 'c':
 146                         ipchroot = 1;
 147                         break;
 148                 case 'C':
 149                         ipchroot = 2;
 150                         break;
 151                 case 'l':
 152                         logging = 1;
 153                         break;
 154                 case 'n':
 155                         suppress_naks = 1;
 156                         break;
 157                 case 's':
 158                         chroot_dir = optarg;
 159                         break;
 160                 case 'u':
 161                         chuser = optarg;
 162                         break;
 163                 case 'w':
 164                         server_mode = 0;
 165                         break;
 166                 default:
 167                         syslog(LOG_WARNING, "ignoring unknown option -%c", ch);
 168                 }
 169         }
 170
 171         if (optind < argc) {
 172                 struct dirlist *dirp;
 173
 174                 /* Get list of directory prefixes. Skip relative pathnames. */
 175                 for (dirp = dirs; optind < argc && dirp < &dirs[MAXDIRS];
 176                      optind++) {
 177                         if (argv[optind][0] == '/') {
 178                                 dirp->name = argv[optind];
 179                                 dirp->len  = strlen(dirp->name);
 180                                 dirp++;
 181                         }
 182                 }
 183         }
 184         else if (chroot_dir) {
 185                 dirs->name = "/";
 186                 dirs->len = 1;
 187         }
 188         if (ipchroot && chroot_dir == NULL) {
 189                 syslog(LOG_ERR, "-c requires -s");
 190                 exit(1);
 191         }
 192
 193         /* If we are not in server mode, skip the whole 'inetd' logic below. */
 194         if (server_mode) {
 195                 on = 1;
 196                 if (ioctl(0, FIONBIO, &on) < 0) {
 197                         syslog(LOG_ERR, "ioctl(FIONBIO): %m");
 198                         exit(1);
 199                 }
 200                 fromlen = sizeof (from);
 201                 n = recvfrom(0, buf, sizeof (buf), 0,
 202                         (struct sockaddr *)&from, &fromlen);
 203                 if (n < 0) {
 204                         syslog(LOG_ERR, "recvfrom: %m");
 205                         exit(1);
 206                 }
 207                 /*
 208                  * Now that we have read the message out of the UDP
 209                  * socket, we fork and exit.  Thus, inetd will go back
 210                  * to listening to the kdump port, and the next request
 211                  * to come in will start up a new instance of kdumpd.
 212                  *
 213                  * We do this so that inetd can run kdumpd in "wait" mode.
 214                  * The problem with kdumpd running in "nowait" mode is that
 215                  * inetd may get one or more successful "selects" on the
 216                  * kdump port before we do our receive, so more than one
 217                  * instance of kdumpd may be started up.  Worse, if kdumpd
 218                  * breaks before doing the above "recvfrom", inetd would
 219                  * spawn endless instances, clogging the system.
 220                  */
 221                 {
 222                         int pid;
 223                         int i;
 224                         socklen_t j;
 225
 226                         for (i = 1; i < 20; i++) {
 227                                 pid = fork();
 228                                 if (pid < 0) {
 229                                         sleep(i);
 230                                         /*
 231                                          * flush out to most recently sent request.
 232                                          *
 233                                          * This may drop some requests, but those
 234                                          * will be resent by the clients when
 235                                          * they timeout.  The positive effect of
 236                                          * this flush is to (try to) prevent more
 237                                          * than one kdumpd being started up to service
 238                                          * a single request from a single client.
 239                                          */
 240                                         j = sizeof from;
 241                                         i = recvfrom(0, buf, sizeof (buf), 0,
 242                                                 (struct sockaddr *)&from, &j);
 243                                         if (i > 0) {
 244                                                 n = i;
 245                                                 fromlen = j;
 246                                         }
 247                                 } else {
 248                                         break;
 249                                 }
 250                         }
 251                         if (pid < 0) {
 252                                 syslog(LOG_ERR, "fork: %m");
 253                                 exit(1);
 254                         } else if (pid != 0) {
 255                                 exit(0);
 256                         }
 257                 }
 258         }
 259
 260         /*
 261          * Since we exit here, we should do that only after the above
 262          * recvfrom to keep inetd from constantly forking should there
 263          * be a problem.  See the above comment about system clogging.
 264          */
 265         if (chroot_dir) {
 266                 if (ipchroot) {
 267                         char tempchroot[MAXPATHLEN];
 268                         char *tempaddr;
 269                         struct stat sb;
 270                         int statret;
 271
 272                         tempaddr = inet_ntoa(from.sin_addr);
 273                         snprintf(tempchroot, sizeof(tempchroot), "%s/%s", chroot_dir, tempaddr);
 274                         statret = stat(tempchroot, &sb);
 275                         if (((sb.st_mode & S_IFMT ) == S_IFDIR) &&
 276                             (statret == 0 || (statret == -1 && ipchroot == 1)))
 277                                 chroot_dir = tempchroot;
 278                 }
 279                 /* Must get this before chroot because /etc might go away */
 280                 if ((nobody = getpwnam(chuser)) == NULL) {
 281                         syslog(LOG_ERR, "%s: no such user", chuser);
 282                         exit(1);
 283                 }
 284                 if (chroot(chroot_dir)) {
 285                         syslog(LOG_ERR, "chroot: %s: %m", chroot_dir);
 286                         exit(1);
 287                 }
 288                 chdir( "/" );
 289                 setuid(nobody->pw_uid);
 290         } else if (0 !=  chdir(dirs->name)) {
 291             syslog(LOG_ERR, "chdir%s: %m", dirs->name);
 292         }
 293
 294         from.sin_family = AF_INET;
 295         alarm(0);
 296         close(0);
 297         close(1);
 298         peer = socket(AF_INET, SOCK_DGRAM, 0);
 299         if (peer < 0) {
 300                 syslog(LOG_ERR, "socket: %m");
 301                 exit(1);
 302         }
 303         memset(&sin, 0, sizeof(sin));
 304         sin.sin_family = AF_INET;
 305
 306         if (!server_mode) {
 307                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
 308                 sin.sin_port = htons((uint16_t) DEFAULT_KDUMPD_PORTNO);
 309         }
 310
 311         if (bind(peer, (struct sockaddr *)&sin, sizeof (sin)) < 0) {
 312                 syslog(LOG_ERR, "bind: %m");
 313                 exit(1);
 314         }
 315
 316         if (!server_mode) {
 317                 /*
 318                  * Wait for an incoming message from a remote peer, note that we need to
 319                  * populate n since kdump() expect the first message to be in buf
 320                  * already.
 321                  */
 322                 socklen_t slen = sizeof(from);
 323                 n = recvfrom(peer, buf, sizeof(buf), 0,
 324                         (struct sockaddr *) &from, &slen);
 325                 if (n <= 0) {
 326                         syslog(LOG_ERR, "recvfrom: %m");
 327                         exit(1);
 328                 }
 329         }
 330
 331         if (connect(peer, (struct sockaddr *)&from, sizeof(from)) < 0) {
 332                 syslog(LOG_ERR, "connect: %m");
 333                 exit(1);
 334         }
 335         tp = (struct kdumphdr *)buf;
 336         tp->th_opcode = ntohs(tp->th_opcode);
 337         if (tp->th_opcode == WRQ)
 338                 kdump(tp, n);
 339         exit(1);
 340 }
 341
 342 struct formats;
 343 int     validate_access __P((char **, int));
 344
 345 void    recvfile __P((struct formats *));
 346
 347 struct formats {
 348         char    *f_mode;
 349         int     (*f_validate) __P((char **, int));
 350
 351         void    (*f_recv) __P((struct formats *));
 352         int     f_convert;
 353 } formats[] = {
 354   { "netascii", validate_access, recvfile, 1 },
 355   { "octet",    validate_access, recvfile, 0 },
 356   { 0 }
 357 };
 358
 359 /*
 360  * Handle initial connection protocol.
 361  */
 362 void
 363 kdump(tp, size)
 364         struct kdumphdr *tp;
 365         int size;
 366 {
 367         register char *cp;
 368         int first = 1, ecode;
 369         register struct formats *pf;
 370         char *filename, *mode = NULL;
 371
 372         filename = cp = tp->th_stuff;
 373 again:
 374         while (cp < buf + size) {
 375                 if (*cp == '\0')
 376                         break;
 377                 cp++;
 378         }
 379         if (*cp != '\0') {
 380                 nak(EBADOP);
 381                 exit(1);
 382         }
 383         if (first) {
 384                 mode = ++cp;
 385                 first = 0;
 386                 goto again;
 387         }
 388         for (cp = mode; *cp; cp++)
 389                 if (isupper(*cp))
 390                         *cp = tolower(*cp);
 391
 392         cp++;
 393         if (strncmp(KDP_FEATURE_MASK_STRING, cp, sizeof(KDP_FEATURE_MASK_STRING)) == 0) {
 394                 kdp_crashdump_feature_mask = ntohl(*(uint32_t *) (cp + sizeof(KDP_FEATURE_MASK_STRING)));
 395                 kdp_feature_large_crashdumps = kdp_crashdump_feature_mask & KDP_FEATURE_LARGE_CRASHDUMPS;
 396                 kdp_feature_large_packets = kdp_crashdump_feature_mask & KDP_FEATURE_LARGE_PKT_SIZE;
 397
 398                 if (kdp_feature_large_packets) {
 399                         kdp_crashdump_pkt_size = KDP_LARGE_CRASHDUMP_PKT_SIZE;
 400                         kdp_crashdump_seg_size = kdp_crashdump_pkt_size - sizeof(struct kdumphdr);
 401                 }
 402                 syslog(KDUMPD_DEBUG_LEVEL, "Received feature mask %s:0x%x", cp, kdp_crashdump_feature_mask);
 403         } else
 404                 syslog(KDUMPD_DEBUG_LEVEL, "Unable to locate feature mask, mode: %s", mode);
 405
 406         for (pf = formats; pf->f_mode; pf++)
 407                 if (strcmp(pf->f_mode, mode) == 0)
 408                         break;
 409         if (pf->f_mode == 0) {
 410                 nak(EBADOP);
 411                 exit(1);
 412         }
 413         ecode = (*pf->f_validate)(&filename, tp->th_opcode);
 414         if (logging) {
 415                 syslog(KDUMPD_DEBUG_LEVEL, "%s: %s request for %s: %s", verifyhost(&from),
 416                         tp->th_opcode == WRQ ? "write" : "read",
 417                         filename, errtomsg(ecode));
 418         }
 419         if (ecode) {
 420                 /*
 421                  * Avoid storms of naks to a RRQ broadcast for a relative
 422                  * bootfile pathname from a diskless Sun.
 423                  */
 424                 if (suppress_naks && *filename != '/' && ecode == ENOTFOUND)
 425                         exit(0);
 426                 nak(ecode);
 427                 exit(1);
 428         }
 429         if (tp->th_opcode == WRQ)
 430                 (*pf->f_recv)(pf);
 431
 432         exit(0);
 433 }
 434
 435
 436 FILE *file;
 437
 438 /*
 439  * Validate file access. We only allow storage of files that do not already
 440  * exist, and that do not include directory specifiers in their pathnames.
 441  * This is because kernel coredump filenames should always be of the form
 442  * "core-version-IP as dotted quad-random string" as in :
 443  * core-custom-17.202.40.204-a75b4eec
 444  * The file is written to the directory supplied as the first argument
 445  * in inetd.conf
 446  */
 447
 448 int
 449 validate_access(char **filep, int mode)
 450 {
 451   struct stat stbuf;
 452   int   fd;
 453   char *filename = *filep;
 454   static char pathname[MAXPATHLEN];
 455
 456   if (strstr(filename, "/") || strstr(filename, ".."))
 457     return (EACCESS);
 458
 459   snprintf(pathname, sizeof(pathname), "./%s", filename);
 460
 461   if (0 == stat(pathname, &stbuf))
 462     return (EEXIST);
 463
 464   if (errno != ENOENT)
 465     return (errno);
 466
 467
 468   fd = open(filename, O_RDWR|O_CREAT|O_TRUNC , S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
 469
 470   if (fd < 0)
 471     return (errno + 100);
 472
 473   file = fdopen(fd, (mode == RRQ)? "r":"w");
 474   if (file == NULL) {
 475     return errno+100;
 476   }
 477
 478   return (0);
 479 }
 480
 481 int     timeout;
 482 jmp_buf timeoutbuf;
 483
 484 void
 485 timer()
 486 {
 487
 488         timeout += rexmtval;
 489         if (timeout >= maxtimeout)
 490           {
 491             longjmp(timeoutbuf, 2);
 492           }
 493         longjmp(timeoutbuf, 1);
 494 }
 495
 496 void
 497 justquit()
 498 {
 499         exit(0);
 500 }
 501
 502 /*
 503  * Receive a file.
 504  */
 505 void
 506 recvfile(pf)
 507         struct formats *pf;
 508 {
 509         struct kdumphdr *dp, *w_init();
 510         register struct kdumphdr *ap;    /* ack buffer */
 511         register int n, size;
 512         volatile unsigned int block;
 513         volatile unsigned int jmpval = 0;
 514
 515         signal(SIGALRM, timer);
 516         dp = w_init();
 517         ap = (struct kdumphdr *)ackbuf;
 518         block = 0;
 519         do {
 520 send_seek_ack:  timeout = 0;
 521                 if (block == 0)
 522                         ap->th_opcode = htons((u_short)ACK | ((kdp_feature_large_crashdumps | kdp_feature_large_packets)  << 8));
 523                 else
 524                         ap->th_opcode = htons((u_short)ACK);
 525                 ap->th_block = htonl((unsigned int)block);
 526                 block++;
 527                 jmpval = setjmp(timeoutbuf);
 528                 if (2 == jmpval)
 529                   {
 530                     syslog (LOG_ERR, "Timing out and flushing file to disk");
 531                     goto flushfile;
 532                   }
 533 send_ack:
 534                 if (send(peer, ackbuf, 6 , 0) != 6) {
 535                         syslog(LOG_ERR, "write: %m");
 536                         goto abort;
 537                 }
 538                 write_behind(file, pf->f_convert);
 539                 for ( ; ; ) {
 540                         alarm(rexmtval);
 541                         n = recv(peer, dp, kdp_crashdump_pkt_size, 0);
 542                         alarm(0);
 543                         if (n < 0) {            /* really? */
 544                                 syslog(LOG_ERR, "read: %m");
 545                                 goto abort;
 546                         }
 547                         dp->th_opcode = ntohs((u_short)dp->th_opcode);
 548                         dp->th_block = ntohl((unsigned int)dp->th_block);
 549 #if     DEBUG
 550                         syslog(KDUMPD_DEBUG_LEVEL, "Received packet type %u, block %u\n", (unsigned)dp->th_opcode, (unsigned)dp->th_block);
 551 #endif
 552
 553                         if (dp->th_opcode == ERROR)
 554                                 goto abort;
 555
 556                         if (dp->th_opcode == KDP_EOF)
 557                           {
 558                             syslog (LOG_ERR, "Received last panic dump packet");
 559                             goto final_ack;
 560                           }
 561                         if (dp->th_opcode == KDP_SEEK)
 562                           {
 563                             if (dp->th_block == block)
 564                               {
 565                                 off_t crashdump_offset = 0;
 566                                 unsigned int tempoff = 0;
 567
 568                                 if (kdp_feature_large_crashdumps) {
 569                                         crashdump_offset = OSSwapBigToHostInt64((*(uint64_t *)dp->th_data));
 570                                 }
 571                                 else {
 572                                 bcopy (dp->th_data, &tempoff, sizeof(unsigned int));
 573                                 crashdump_offset = ntohl(tempoff);
 574                                 }
 575
 576 #if     DEBUG
 577                                 syslog(KDUMPD_DEBUG_LEVEL, "Seeking to offset 0x%llx\n", crashdump_offset);
 578 #endif
 579                                 errno = 0;
 580                                 lseek(fileno (file), crashdump_offset, SEEK_SET);
 581                                 if (errno)
 582                                   syslog (LOG_ERR, "lseek: %m");
 583
 584                                 goto send_seek_ack;
 585                               }
 586                             (void) synchnet(peer);
 587                             if (dp->th_block == (block-1))
 588                             {
 589                                     syslog (LOG_DAEMON|LOG_ERR, "Retransmitting seek ack - current block %u, received block %u", block, dp->th_block);
 590                                     goto send_ack;          /* rexmit */
 591                             }
 592                         }
 593
 594                         if (dp->th_opcode == DATA) {
 595                                 if (dp->th_block == block) {
 596                                         break;   /* normal */
 597                                 }
 598                                 /* Re-synchronize with the other side */
 599                                 (void) synchnet(peer);
 600                                 if (dp->th_block == (block-1))
 601                                   {
 602                                     syslog (LOG_DAEMON|LOG_ERR, "Retransmitting ack - current block %u, received block %u", block, dp->th_block);
 603                                     goto send_ack;          /* rexmit */
 604                                   }
 605                                 else
 606                                   syslog (LOG_DAEMON|LOG_ERR, "Not retransmitting ack - current block %u, received block %u", block, dp->th_block);
 607                         }
 608                 }
 609 #if DEBUG
 610                 syslog(KDUMPD_DEBUG_LEVEL, "Writing block sized %u, current offset 0x%llx\n", n - 6, ftello(file));
 611 #endif
 612                 size = writeit(file, &dp, n - 6, pf->f_convert);
 613                 if (size != (n-6)) {                    /* ahem */
 614                         if (size < 0) nak(errno + 100);
 615                         else nak(ENOSPACE);
 616                         goto abort;
 617                 }
 618         } while (dp->th_opcode != KDP_EOF);
 619
 620 final_ack:
 621         ap->th_opcode = htons((u_short)ACK);    /* send the "final" ack */
 622         ap->th_block = htonl((unsigned int) (block));
 623         (void) send(peer, ackbuf, 6, 0);
 624 flushfile:
 625         write_behind(file, pf->f_convert);
 626         (void) fclose(file);            /* close data file */
 627         syslog (LOG_ERR, "file closed, sending final ACK\n");
 628
 629         signal(SIGALRM, justquit);      /* just quit on timeout */
 630         alarm(rexmtval);
 631         n = recv(peer, buf, sizeof (buf), 0); /* normally times out and quits */
 632         alarm(0);
 633         if (n >= 6 &&                   /* if read some data */
 634             dp->th_opcode == DATA &&    /* and got a data block */
 635             block == dp->th_block) {    /* then my last ack was lost */
 636                 (void) send(peer, ackbuf, 6, 0);     /* resend final ack */
 637         }
 638 abort:
 639         return;
 640 }
 641
 642 /* update if needed, when adding new errmsgs */
 643 #define MAXERRMSGLEN    40
 644
 645 struct errmsg {
 646         int     e_code;
 647         char    *e_msg;
 648 } errmsgs[] = {
 649         { EUNDEF,       "Undefined error code" },
 650         { ENOTFOUND,    "File not found" },
 651         { EACCESS,      "Access violation" },
 652         { ENOSPACE,     "Disk full or allocation exceeded" },
 653         { EBADOP,       "Illegal KDUMP operation" },
 654         { EBADID,       "Unknown transfer ID" },
 655         { EEXISTS,      "File already exists" },
 656         { ENOUSER,      "No such user" },
 657         { -1,           0 }
 658 };
 659
 660 static char *
 661 errtomsg(error)
 662         int error;
 663 {
 664         static char buf[20];
 665         register struct errmsg *pe;
 666         if (error == 0)
 667                 return "success";
 668         for (pe = errmsgs; pe->e_code >= 0; pe++)
 669                 if (pe->e_code == error)
 670                         return pe->e_msg;
 671         snprintf(buf, sizeof(buf), "error %d", error);
 672         return buf;
 673 }
 674
 675 /*
 676  * Send a nak packet (error message).
 677  * Error code passed in is one of the
 678  * standard KDUMP codes, or a UNIX errno
 679  * offset by 100.
 680  */
 681 static void
 682 nak(error)
 683         int error;
 684 {
 685         register struct kdumphdr *tp;
 686         int length;
 687         register struct errmsg *pe;
 688
 689         tp = (struct kdumphdr *)buf;
 690         tp->th_opcode = htons((u_short)ERROR);
 691         tp->th_code = htons((unsigned int)error);
 692         for (pe = errmsgs; pe->e_code >= 0; pe++)
 693                 if (pe->e_code == error)
 694                         break;
 695         if (pe->e_code < 0) {
 696                 pe->e_msg = strerror(error - 100);
 697                 tp->th_code = EUNDEF;   /* set 'undef' errorcode */
 698         }
 699         if (strlen(pe->e_msg) > MAXERRMSGLEN) {
 700                 syslog(LOG_ERR, "nak: error msg too long");
 701                 return;
 702         }
 703
 704         strlcpy(tp->th_msg, pe->e_msg, MAXERRMSGLEN);
 705         length = strlen(pe->e_msg);
 706         tp->th_msg[length] = '\0';
 707         length += 5;
 708         if (send(peer, buf, length, 0) != length)
 709                 syslog(LOG_ERR, "nak: %m");
 710
 711         return;
 712 }
 713
 714 static char *
 715 verifyhost(fromp)
 716         struct sockaddr_in *fromp;
 717 {
 718         struct hostent *hp;
 719
 720         hp = gethostbyaddr((char *)&fromp->sin_addr, sizeof(fromp->sin_addr),
 721                 fromp->sin_family);
 722         if(hp)
 723                 return hp->h_name;
 724         else
 725                 return inet_ntoa(fromp->sin_addr);
 726 }