resolv/ns_print.c

   1 /*
   2  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (c) 1996-1999 by Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
  10  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  11  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  12  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  13  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  14  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  15  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  16  * SOFTWARE.
  17  */
  18
  19 /* Import. */
  20
  21 #include <sys/types.h>
  22 #include <sys/socket.h>
  23
  24 #include <netinet/in.h>
  25 #include <arpa/nameser.h>
  26 #include <arpa/inet.h>
  27
  28 #include <assert.h>
  29 #include <errno.h>
  30 #include <resolv.h>
  31 #include <string.h>
  32 #include <ctype.h>
  33
  34 #define SPRINTF(x) ((size_t)sprintf x)
  35
  36 /* Forward. */
  37
  38 static size_t   prune_origin(const char *name, const char *origin);
  39 static int      charstr(const u_char *rdata, const u_char *edata,
  40                         char **buf, size_t *buflen);
  41 static int      addname(const u_char *msg, size_t msglen,
  42                         const u_char **p, const char *origin,
  43                         char **buf, size_t *buflen);
  44 static void     addlen(size_t len, char **buf, size_t *buflen);
  45 static int      addstr(const char *src, size_t len,
  46                        char **buf, size_t *buflen);
  47 static int      addtab(size_t len, size_t target, int spaced,
  48                        char **buf, size_t *buflen);
  49
  50 /* Macros. */
  51
  52 #define T(x) \
  53         do { \
  54                 if ((x) < 0) \
  55                         return (-1); \
  56         } while (0)
  57
  58 /* Public. */
  59
  60 /*%
  61  *      Convert an RR to presentation format.
  62  *
  63  * return:
  64  *\li   Number of characters written to buf, or -1 (check errno).
  65  */
  66 int
  67 ns_sprintrr(const ns_msg *handle, const ns_rr *rr,
  68             const char *name_ctx, const char *origin,
  69             char *buf, size_t buflen)
  70 {
  71         int n;
  72
  73         n = ns_sprintrrf(ns_msg_base(*handle), ns_msg_size(*handle),
  74                          ns_rr_name(*rr), ns_rr_class(*rr), ns_rr_type(*rr),
  75                          ns_rr_ttl(*rr), ns_rr_rdata(*rr), ns_rr_rdlen(*rr),
  76                          name_ctx, origin, buf, buflen);
  77         return (n);
  78 }
  79 libresolv_hidden_def (ns_sprintrr)
  80
  81 /*%
  82  *      Convert the fields of an RR into presentation format.
  83  *
  84  * return:
  85  *\li   Number of characters written to buf, or -1 (check errno).
  86  */
  87 int
  88 ns_sprintrrf(const u_char *msg, size_t msglen,
  89             const char *name, ns_class class, ns_type type,
  90             u_long ttl, const u_char *rdata, size_t rdlen,
  91             const char *name_ctx, const char *origin,
  92             char *buf, size_t buflen)
  93 {
  94         const char *obuf = buf;
  95         const u_char *edata = rdata + rdlen;
  96         int spaced = 0;
  97
  98         const char *comment;
  99         char tmp[100];
 100         char errbuf[40];
 101         int len, x;
 102
 103         /*
 104          * Owner.
 105          */
 106         if (name_ctx != NULL && __libc_ns_samename (name_ctx, name) == 1)
 107                 T(addstr("\t\t\t", 3, &buf, &buflen));
 108         else {
 109                 len = prune_origin(name, origin);
 110                 if (*name == '\0') {
 111                         goto root;
 112                 } else if (len == 0) {
 113                         T(addstr("@\t\t\t", 4, &buf, &buflen));
 114                 } else {
 115                         T(addstr(name, len, &buf, &buflen));
 116                         /* Origin not used or not root, and no trailing dot? */
 117                         if (((origin == NULL || origin[0] == '\0') ||
 118                              (origin[0] != '.' && origin[1] != '\0' &&
 119                               name[len] == '\0')) && name[len - 1] != '.') {
 120  root:
 121                                 T(addstr(".", 1, &buf, &buflen));
 122                                 len++;
 123                         }
 124                         T(spaced = addtab(len, 24, spaced, &buf, &buflen));
 125                 }
 126         }
 127
 128         /*
 129          * TTL, Class, Type.
 130          */
 131         T(x = ns_format_ttl(ttl, buf, buflen));
 132         addlen(x, &buf, &buflen);
 133         len = SPRINTF((tmp, " %s %s", p_class(class), p_type(type)));
 134         T(addstr(tmp, len, &buf, &buflen));
 135         T(spaced = addtab(x + len, 16, spaced, &buf, &buflen));
 136
 137         /*
 138          * RData.
 139          */
 140         switch (type) {
 141         case ns_t_a:
 142           if (rdlen != (size_t)NS_INADDRSZ)
 143                         goto formerr;
 144                 (void) inet_ntop(AF_INET, rdata, buf, buflen);
 145                 addlen(strlen(buf), &buf, &buflen);
 146                 break;
 147
 148         case ns_t_cname:
 149         case ns_t_mb:
 150         case ns_t_mg:
 151         case ns_t_mr:
 152         case ns_t_ns:
 153         case ns_t_ptr:
 154         case ns_t_dname:
 155                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 156                 break;
 157
 158         case ns_t_hinfo:
 159         case ns_t_isdn:
 160                 /* First word. */
 161                 T(len = charstr(rdata, edata, &buf, &buflen));
 162                 if (len == 0)
 163                         goto formerr;
 164                 rdata += len;
 165                 T(addstr(" ", 1, &buf, &buflen));
 166
 167
 168                 /* Second word, optional in ISDN records. */
 169                 if (type == ns_t_isdn && rdata == edata)
 170                         break;
 171
 172                 T(len = charstr(rdata, edata, &buf, &buflen));
 173                 if (len == 0)
 174                         goto formerr;
 175                 rdata += len;
 176                 break;
 177
 178         case ns_t_soa: {
 179                 u_long t;
 180
 181                 /* Server name. */
 182                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 183                 T(addstr(" ", 1, &buf, &buflen));
 184
 185                 /* Administrator name. */
 186                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 187                 T(addstr(" (\n", 3, &buf, &buflen));
 188                 spaced = 0;
 189
 190                 if ((edata - rdata) != 5*NS_INT32SZ)
 191                         goto formerr;
 192
 193                 /* Serial number. */
 194                 t = ns_get32(rdata);  rdata += NS_INT32SZ;
 195                 T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
 196                 len = SPRINTF((tmp, "%lu", t));
 197                 T(addstr(tmp, len, &buf, &buflen));
 198                 T(spaced = addtab(len, 16, spaced, &buf, &buflen));
 199                 T(addstr("; serial\n", 9, &buf, &buflen));
 200                 spaced = 0;
 201
 202                 /* Refresh interval. */
 203                 t = ns_get32(rdata);  rdata += NS_INT32SZ;
 204                 T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
 205                 T(len = ns_format_ttl(t, buf, buflen));
 206                 addlen(len, &buf, &buflen);
 207                 T(spaced = addtab(len, 16, spaced, &buf, &buflen));
 208                 T(addstr("; refresh\n", 10, &buf, &buflen));
 209                 spaced = 0;
 210
 211                 /* Retry interval. */
 212                 t = ns_get32(rdata);  rdata += NS_INT32SZ;
 213                 T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
 214                 T(len = ns_format_ttl(t, buf, buflen));
 215                 addlen(len, &buf, &buflen);
 216                 T(spaced = addtab(len, 16, spaced, &buf, &buflen));
 217                 T(addstr("; retry\n", 8, &buf, &buflen));
 218                 spaced = 0;
 219
 220                 /* Expiry. */
 221                 t = ns_get32(rdata);  rdata += NS_INT32SZ;
 222                 T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
 223                 T(len = ns_format_ttl(t, buf, buflen));
 224                 addlen(len, &buf, &buflen);
 225                 T(spaced = addtab(len, 16, spaced, &buf, &buflen));
 226                 T(addstr("; expiry\n", 9, &buf, &buflen));
 227                 spaced = 0;
 228
 229                 /* Minimum TTL. */
 230                 t = ns_get32(rdata);  rdata += NS_INT32SZ;
 231                 T(addstr("\t\t\t\t\t", 5, &buf, &buflen));
 232                 T(len = ns_format_ttl(t, buf, buflen));
 233                 addlen(len, &buf, &buflen);
 234                 T(addstr(" )", 2, &buf, &buflen));
 235                 T(spaced = addtab(len, 16, spaced, &buf, &buflen));
 236                 T(addstr("; minimum\n", 10, &buf, &buflen));
 237
 238                 break;
 239             }
 240
 241         case ns_t_mx:
 242         case ns_t_afsdb:
 243         case ns_t_rt: {
 244                 u_int t;
 245
 246                 if (rdlen < (size_t)NS_INT16SZ)
 247                         goto formerr;
 248
 249                 /* Priority. */
 250                 t = ns_get16(rdata);
 251                 rdata += NS_INT16SZ;
 252                 len = SPRINTF((tmp, "%u ", t));
 253                 T(addstr(tmp, len, &buf, &buflen));
 254
 255                 /* Target. */
 256                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 257
 258                 break;
 259             }
 260
 261         case ns_t_px: {
 262                 u_int t;
 263
 264                 if (rdlen < (size_t)NS_INT16SZ)
 265                         goto formerr;
 266
 267                 /* Priority. */
 268                 t = ns_get16(rdata);
 269                 rdata += NS_INT16SZ;
 270                 len = SPRINTF((tmp, "%u ", t));
 271                 T(addstr(tmp, len, &buf, &buflen));
 272
 273                 /* Name1. */
 274                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 275                 T(addstr(" ", 1, &buf, &buflen));
 276
 277                 /* Name2. */
 278                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 279
 280                 break;
 281             }
 282
 283         case ns_t_x25:
 284                 T(len = charstr(rdata, edata, &buf, &buflen));
 285                 if (len == 0)
 286                         goto formerr;
 287                 rdata += len;
 288                 break;
 289
 290         case ns_t_txt:
 291                 while (rdata < edata) {
 292                         T(len = charstr(rdata, edata, &buf, &buflen));
 293                         if (len == 0)
 294                                 goto formerr;
 295                         rdata += len;
 296                         if (rdata < edata)
 297                                 T(addstr(" ", 1, &buf, &buflen));
 298                 }
 299                 break;
 300
 301         case ns_t_nsap: {
 302                 char t[2+255*3];
 303
 304                 (void) inet_nsap_ntoa(rdlen, rdata, t);
 305                 T(addstr(t, strlen(t), &buf, &buflen));
 306                 break;
 307             }
 308
 309         case ns_t_aaaa:
 310           if (rdlen != (size_t)NS_IN6ADDRSZ)
 311                         goto formerr;
 312                 (void) inet_ntop(AF_INET6, rdata, buf, buflen);
 313                 addlen(strlen(buf), &buf, &buflen);
 314                 break;
 315
 316         case ns_t_loc: {
 317                 char t[255];
 318
 319                 /* XXX protocol format checking? */
 320                 (void) loc_ntoa(rdata, t);
 321                 T(addstr(t, strlen(t), &buf, &buflen));
 322                 break;
 323             }
 324
 325         case ns_t_naptr: {
 326                 u_int order, preference;
 327                 char t[50];
 328
 329                 if (rdlen < 2U*NS_INT16SZ)
 330                         goto formerr;
 331
 332                 /* Order, Precedence. */
 333                 order = ns_get16(rdata);        rdata += NS_INT16SZ;
 334                 preference = ns_get16(rdata);   rdata += NS_INT16SZ;
 335                 len = SPRINTF((t, "%u %u ", order, preference));
 336                 T(addstr(t, len, &buf, &buflen));
 337
 338                 /* Flags. */
 339                 T(len = charstr(rdata, edata, &buf, &buflen));
 340                 if (len == 0)
 341                         goto formerr;
 342                 rdata += len;
 343                 T(addstr(" ", 1, &buf, &buflen));
 344
 345                 /* Service. */
 346                 T(len = charstr(rdata, edata, &buf, &buflen));
 347                 if (len == 0)
 348                         goto formerr;
 349                 rdata += len;
 350                 T(addstr(" ", 1, &buf, &buflen));
 351
 352                 /* Regexp. */
 353                 T(len = charstr(rdata, edata, &buf, &buflen));
 354                 if (len < 0)
 355                         return (-1);
 356                 if (len == 0)
 357                         goto formerr;
 358                 rdata += len;
 359                 T(addstr(" ", 1, &buf, &buflen));
 360
 361                 /* Server. */
 362                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 363                 break;
 364             }
 365
 366         case ns_t_srv: {
 367                 u_int priority, weight, port;
 368                 char t[50];
 369
 370                 if (rdlen < 3U*NS_INT16SZ)
 371                         goto formerr;
 372
 373                 /* Priority, Weight, Port. */
 374                 priority = ns_get16(rdata);  rdata += NS_INT16SZ;
 375                 weight   = ns_get16(rdata);  rdata += NS_INT16SZ;
 376                 port     = ns_get16(rdata);  rdata += NS_INT16SZ;
 377                 len = SPRINTF((t, "%u %u %u ", priority, weight, port));
 378                 T(addstr(t, len, &buf, &buflen));
 379
 380                 /* Server. */
 381                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 382                 break;
 383             }
 384
 385         case ns_t_minfo:
 386         case ns_t_rp:
 387                 /* Name1. */
 388                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 389                 T(addstr(" ", 1, &buf, &buflen));
 390
 391                 /* Name2. */
 392                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 393
 394                 break;
 395
 396         case ns_t_wks: {
 397                 int n, lcnt;
 398
 399                 if (rdlen < 1U + NS_INT32SZ)
 400                         goto formerr;
 401
 402                 /* Address. */
 403                 (void) inet_ntop(AF_INET, rdata, buf, buflen);
 404                 addlen(strlen(buf), &buf, &buflen);
 405                 rdata += NS_INADDRSZ;
 406
 407                 /* Protocol. */
 408                 len = SPRINTF((tmp, " %u ( ", *rdata));
 409                 T(addstr(tmp, len, &buf, &buflen));
 410                 rdata += NS_INT8SZ;
 411
 412                 /* Bit map. */
 413                 n = 0;
 414                 lcnt = 0;
 415                 while (rdata < edata) {
 416                         u_int c = *rdata++;
 417                         do {
 418                                 if (c & 0200) {
 419                                         if (lcnt == 0) {
 420                                                 T(addstr("\n\t\t\t\t", 5,
 421                                                          &buf, &buflen));
 422                                                 lcnt = 10;
 423                                                 spaced = 0;
 424                                         }
 425                                         len = SPRINTF((tmp, "%d ", n));
 426                                         T(addstr(tmp, len, &buf, &buflen));
 427                                         lcnt--;
 428                                 }
 429                                 c <<= 1;
 430                         } while (++n & 07);
 431                 }
 432                 T(addstr(")", 1, &buf, &buflen));
 433
 434                 break;
 435             }
 436
 437         case ns_t_cert: {
 438                 u_int c_type, key_tag, alg;
 439                 int n;
 440                 unsigned int siz;
 441                 char base64_cert[8192], tmp[40];
 442                 const char *leader;
 443
 444                 c_type  = ns_get16(rdata); rdata += NS_INT16SZ;
 445                 key_tag = ns_get16(rdata); rdata += NS_INT16SZ;
 446                 alg = (u_int) *rdata++;
 447
 448                 len = SPRINTF((tmp, "%d %d %d ", c_type, key_tag, alg));
 449                 T(addstr(tmp, len, &buf, &buflen));
 450                 siz = (edata-rdata)*4/3 + 4; /* "+4" accounts for trailing \0 */
 451                 if (siz > sizeof(base64_cert) * 3/4) {
 452                         const char *str = "record too long to print";
 453                         T(addstr(str, strlen(str), &buf, &buflen));
 454                 }
 455                 else {
 456                         len = b64_ntop(rdata, edata-rdata, base64_cert, siz);
 457
 458                         if (len < 0)
 459                                 goto formerr;
 460                         else if (len > 15) {
 461                                 T(addstr(" (", 2, &buf, &buflen));
 462                                 leader = "\n\t\t";
 463                                 spaced = 0;
 464                         }
 465                         else
 466                                 leader = " ";
 467
 468                         for (n = 0; n < len; n += 48) {
 469                                 T(addstr(leader, strlen(leader),
 470                                          &buf, &buflen));
 471                                 T(addstr(base64_cert + n, MIN(len - n, 48),
 472                                          &buf, &buflen));
 473                         }
 474                         if (len > 15)
 475                                 T(addstr(" )", 2, &buf, &buflen));
 476                 }
 477                 break;
 478             }
 479
 480         case ns_t_tkey: {
 481                 /* KJD - need to complete this */
 482                 u_long t;
 483                 int mode, err, keysize;
 484
 485                 /* Algorithm name. */
 486                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 487                 T(addstr(" ", 1, &buf, &buflen));
 488
 489                 /* Inception. */
 490                 t = ns_get32(rdata);  rdata += NS_INT32SZ;
 491                 len = SPRINTF((tmp, "%lu ", t));
 492                 T(addstr(tmp, len, &buf, &buflen));
 493
 494                 /* Expiration. */
 495                 t = ns_get32(rdata);  rdata += NS_INT32SZ;
 496                 len = SPRINTF((tmp, "%lu ", t));
 497                 T(addstr(tmp, len, &buf, &buflen));
 498
 499                 /* Mode , Error, Key Size. */
 500                 /* Priority, Weight, Port. */
 501                 mode = ns_get16(rdata);  rdata += NS_INT16SZ;
 502                 err  = ns_get16(rdata);  rdata += NS_INT16SZ;
 503                 keysize  = ns_get16(rdata);  rdata += NS_INT16SZ;
 504                 len = SPRINTF((tmp, "%u %u %u ", mode, err, keysize));
 505                 T(addstr(tmp, len, &buf, &buflen));
 506
 507                 /* XXX need to dump key, print otherdata length & other data */
 508                 break;
 509             }
 510
 511         case ns_t_tsig: {
 512                 /* BEW - need to complete this */
 513                 int n;
 514
 515                 T(len = addname(msg, msglen, &rdata, origin, &buf, &buflen));
 516                 T(addstr(" ", 1, &buf, &buflen));
 517                 rdata += 8; /*%< time */
 518                 n = ns_get16(rdata); rdata += INT16SZ;
 519                 rdata += n; /*%< sig */
 520                 n = ns_get16(rdata); rdata += INT16SZ; /*%< original id */
 521                 sprintf(buf, "%d", ns_get16(rdata));
 522                 rdata += INT16SZ;
 523                 addlen(strlen(buf), &buf, &buflen);
 524                 break;
 525             }
 526
 527         case ns_t_a6: {
 528                 struct in6_addr a;
 529                 int pbyte, pbit;
 530
 531                 /* prefix length */
 532                 if (rdlen == 0U) goto formerr;
 533                 len = SPRINTF((tmp, "%d ", *rdata));
 534                 T(addstr(tmp, len, &buf, &buflen));
 535                 pbit = *rdata;
 536                 if (pbit > 128) goto formerr;
 537                 pbyte = (pbit & ~7) / 8;
 538                 rdata++;
 539
 540                 /* address suffix: provided only when prefix len != 128 */
 541                 if (pbit < 128) {
 542                         if (rdata + pbyte >= edata) goto formerr;
 543                         memset(&a, 0, sizeof(a));
 544                         memcpy(&a.s6_addr[pbyte], rdata, sizeof(a) - pbyte);
 545                         (void) inet_ntop(AF_INET6, &a, buf, buflen);
 546                         addlen(strlen(buf), &buf, &buflen);
 547                         rdata += sizeof(a) - pbyte;
 548                 }
 549
 550                 /* prefix name: provided only when prefix len > 0 */
 551                 if (pbit == 0)
 552                         break;
 553                 if (rdata >= edata) goto formerr;
 554                 T(addstr(" ", 1, &buf, &buflen));
 555                 T(addname(msg, msglen, &rdata, origin, &buf, &buflen));
 556
 557                 break;
 558             }
 559
 560         case ns_t_opt: {
 561                 len = SPRINTF((tmp, "%u bytes", class));
 562                 T(addstr(tmp, len, &buf, &buflen));
 563                 break;
 564             }
 565
 566         default:
 567                 snprintf (errbuf, sizeof (errbuf), "unknown RR type %d", type);
 568                 comment = errbuf;
 569                 goto hexify;
 570         }
 571         return (buf - obuf);
 572  formerr:
 573         comment = "RR format error";
 574  hexify: {
 575         int n, m;
 576         char *p;
 577
 578         len = SPRINTF((tmp, "\\# %u%s\t; %s", (unsigned)(edata - rdata),
 579                        rdlen != 0U ? " (" : "", comment));
 580         T(addstr(tmp, len, &buf, &buflen));
 581         while (rdata < edata) {
 582                 p = tmp;
 583                 p += SPRINTF((p, "\n\t"));
 584                 spaced = 0;
 585                 n = MIN(16, edata - rdata);
 586                 for (m = 0; m < n; m++)
 587                         p += SPRINTF((p, "%02x ", rdata[m]));
 588                 T(addstr(tmp, p - tmp, &buf, &buflen));
 589                 if (n < 16) {
 590                         T(addstr(")", 1, &buf, &buflen));
 591                         T(addtab(p - tmp + 1, 48, spaced, &buf, &buflen));
 592                 }
 593                 p = tmp;
 594                 p += SPRINTF((p, "; "));
 595                 for (m = 0; m < n; m++)
 596                         *p++ = (isascii(rdata[m]) && isprint(rdata[m]))
 597                                 ? rdata[m]
 598                                 : '.';
 599                 T(addstr(tmp, p - tmp, &buf, &buflen));
 600                 rdata += n;
 601         }
 602         return (buf - obuf);
 603     }
 604 }
 605 libresolv_hidden_def (ns_sprintrrf)
 606
 607 /* Private. */
 608
 609 /*%
 610  * size_t
 611  * prune_origin(name, origin)
 612  *      Find out if the name is at or under the current origin.
 613  * return:
 614  *      Number of characters in name before start of origin,
 615  *      or length of name if origin does not match.
 616  * notes:
 617  *      This function should share code with samedomain().
 618  */
 619 static size_t
 620 prune_origin(const char *name, const char *origin) {
 621         const char *oname = name;
 622
 623         while (*name != '\0') {
 624                 if (origin != NULL && __libc_ns_samename (name, origin) == 1)
 625                         return (name - oname - (name > oname));
 626                 while (*name != '\0') {
 627                         if (*name == '\\') {
 628                                 name++;
 629                                 /* XXX need to handle \nnn form. */
 630                                 if (*name == '\0')
 631                                         break;
 632                         } else if (*name == '.') {
 633                                 name++;
 634                                 break;
 635                         }
 636                         name++;
 637                 }
 638         }
 639         return (name - oname);
 640 }
 641
 642 /*%
 643  * int
 644  * charstr(rdata, edata, buf, buflen)
 645  *      Format a <character-string> into the presentation buffer.
 646  * return:
 647  *      Number of rdata octets consumed
 648  *      0 for protocol format error
 649  *      -1 for output buffer error
 650  * side effects:
 651  *      buffer is advanced on success.
 652  */
 653 static int
 654 charstr(const u_char *rdata, const u_char *edata, char **buf, size_t *buflen) {
 655         const u_char *odata = rdata;
 656         size_t save_buflen = *buflen;
 657         char *save_buf = *buf;
 658
 659         if (addstr("\"", 1, buf, buflen) < 0)
 660                 goto enospc;
 661         if (rdata < edata) {
 662                 int n = *rdata;
 663
 664                 if (rdata + 1 + n <= edata) {
 665                         rdata++;
 666                         while (n-- > 0) {
 667                                 if (strchr("\n\"\\", *rdata) != NULL)
 668                                         if (addstr("\\", 1, buf, buflen) < 0)
 669                                                 goto enospc;
 670                                 if (addstr((const char *)rdata, 1,
 671                                            buf, buflen) < 0)
 672                                         goto enospc;
 673                                 rdata++;
 674                         }
 675                 }
 676         }
 677         if (addstr("\"", 1, buf, buflen) < 0)
 678                 goto enospc;
 679         return (rdata - odata);
 680  enospc:
 681         __set_errno (ENOSPC);
 682         *buf = save_buf;
 683         *buflen = save_buflen;
 684         return (-1);
 685 }
 686
 687 static int
 688 addname(const u_char *msg, size_t msglen,
 689         const u_char **pp, const char *origin,
 690         char **buf, size_t *buflen)
 691 {
 692         size_t newlen, save_buflen = *buflen;
 693         char *save_buf = *buf;
 694         int n;
 695
 696         n = __libc_dn_expand (msg, msg + msglen, *pp, *buf, *buflen);
 697         if (n < 0)
 698                 goto enospc;    /*%< Guess. */
 699         newlen = prune_origin(*buf, origin);
 700         if (**buf == '\0') {
 701                 goto root;
 702         } else if (newlen == 0U) {
 703                 /* Use "@" instead of name. */
 704                 if (newlen + 2 > *buflen)
 705                         goto enospc;        /* No room for "@\0". */
 706                 (*buf)[newlen++] = '@';
 707                 (*buf)[newlen] = '\0';
 708         } else {
 709                 if (((origin == NULL || origin[0] == '\0') ||
 710                     (origin[0] != '.' && origin[1] != '\0' &&
 711                     (*buf)[newlen] == '\0')) && (*buf)[newlen - 1] != '.') {
 712                         /* No trailing dot. */
 713  root:
 714                         if (newlen + 2 > *buflen)
 715                                 goto enospc;    /* No room for ".\0". */
 716                         (*buf)[newlen++] = '.';
 717                         (*buf)[newlen] = '\0';
 718                 }
 719         }
 720         *pp += n;
 721         addlen(newlen, buf, buflen);
 722         **buf = '\0';
 723         return (newlen);
 724  enospc:
 725         __set_errno (ENOSPC);
 726         *buf = save_buf;
 727         *buflen = save_buflen;
 728         return (-1);
 729 }
 730
 731 static void
 732 addlen(size_t len, char **buf, size_t *buflen) {
 733         assert(len <= *buflen);
 734         *buf += len;
 735         *buflen -= len;
 736 }
 737
 738 static int
 739 addstr(const char *src, size_t len, char **buf, size_t *buflen) {
 740         if (len >= *buflen) {
 741                 __set_errno (ENOSPC);
 742                 return (-1);
 743         }
 744         memcpy(*buf, src, len);
 745         addlen(len, buf, buflen);
 746         **buf = '\0';
 747         return (0);
 748 }
 749
 750 static int
 751 addtab(size_t len, size_t target, int spaced, char **buf, size_t *buflen) {
 752         size_t save_buflen = *buflen;
 753         char *save_buf = *buf;
 754         int t;
 755
 756         if (spaced || len >= target - 1) {
 757                 T(addstr("  ", 2, buf, buflen));
 758                 spaced = 1;
 759         } else {
 760                 for (t = (target - len - 1) / 8; t >= 0; t--)
 761                         if (addstr("\t", 1, buf, buflen) < 0) {
 762                                 *buflen = save_buflen;
 763                                 *buf = save_buf;
 764                                 return (-1);
 765                         }
 766                 spaced = 0;
 767         }
 768         return (spaced);
 769 }