contrib/bind9/lib/dns/diff.c

   1 /*
   2  * Copyright (C) 2004, 2005, 2007-2009  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 2000-2003  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and/or 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 ISC DISCLAIMS ALL WARRANTIES WITH
  10  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  11  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  12  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  13  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  14  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  15  * PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 /* $Id: diff.c,v 1.18.50.2 2009/01/05 23:47:22 tbox Exp $ */
  19
  20 /*! \file */
  21
  22 #include <config.h>
  23
  24 #include <stdlib.h>
  25
  26 #include <isc/buffer.h>
  27 #include <isc/file.h>
  28 #include <isc/mem.h>
  29 #include <isc/string.h>
  30 #include <isc/util.h>
  31
  32 #include <dns/db.h>
  33 #include <dns/diff.h>
  34 #include <dns/log.h>
  35 #include <dns/rdataclass.h>
  36 #include <dns/rdatalist.h>
  37 #include <dns/rdataset.h>
  38 #include <dns/rdatastruct.h>
  39 #include <dns/rdatatype.h>
  40 #include <dns/result.h>
  41
  42 #define CHECK(op) \
  43         do { result = (op);                                     \
  44                 if (result != ISC_R_SUCCESS) goto failure;      \
  45         } while (0)
  46
  47 #define DIFF_COMMON_LOGARGS \
  48         dns_lctx, DNS_LOGCATEGORY_GENERAL, DNS_LOGMODULE_DIFF
  49
  50 static dns_rdatatype_t
  51 rdata_covers(dns_rdata_t *rdata) {
  52         return (rdata->type == dns_rdatatype_rrsig ?
  53                 dns_rdata_covers(rdata) : 0);
  54 }
  55
  56 isc_result_t
  57 dns_difftuple_create(isc_mem_t *mctx,
  58                      dns_diffop_t op, dns_name_t *name, dns_ttl_t ttl,
  59                      dns_rdata_t *rdata, dns_difftuple_t **tp)
  60 {
  61         dns_difftuple_t *t;
  62         unsigned int size;
  63         unsigned char *datap;
  64
  65         REQUIRE(tp != NULL && *tp == NULL);
  66
  67         /*
  68          * Create a new tuple.  The variable-size wire-format name data and
  69          * rdata immediately follow the dns_difftuple_t structure
  70          * in memory.
  71          */
  72         size = sizeof(*t) + name->length + rdata->length;
  73         t = isc_mem_allocate(mctx, size);
  74         if (t == NULL)
  75                 return (ISC_R_NOMEMORY);
  76         t->mctx = mctx;
  77         t->op = op;
  78
  79         datap = (unsigned char *)(t + 1);
  80
  81         memcpy(datap, name->ndata, name->length);
  82         dns_name_init(&t->name, NULL);
  83         dns_name_clone(name, &t->name);
  84         t->name.ndata = datap;
  85         datap += name->length;
  86
  87         t->ttl = ttl;
  88
  89         memcpy(datap, rdata->data, rdata->length);
  90         dns_rdata_init(&t->rdata);
  91         dns_rdata_clone(rdata, &t->rdata);
  92         t->rdata.data = datap;
  93         datap += rdata->length;
  94
  95         ISC_LINK_INIT(&t->rdata, link);
  96         ISC_LINK_INIT(t, link);
  97         t->magic = DNS_DIFFTUPLE_MAGIC;
  98
  99         INSIST(datap == (unsigned char *)t + size);
 100
 101         *tp = t;
 102         return (ISC_R_SUCCESS);
 103 }
 104
 105 void
 106 dns_difftuple_free(dns_difftuple_t **tp) {
 107         dns_difftuple_t *t = *tp;
 108         REQUIRE(DNS_DIFFTUPLE_VALID(t));
 109         dns_name_invalidate(&t->name);
 110         t->magic = 0;
 111         isc_mem_free(t->mctx, t);
 112         *tp = NULL;
 113 }
 114
 115 isc_result_t
 116 dns_difftuple_copy(dns_difftuple_t *orig, dns_difftuple_t **copyp) {
 117         return (dns_difftuple_create(orig->mctx, orig->op, &orig->name,
 118                                      orig->ttl, &orig->rdata, copyp));
 119 }
 120
 121 void
 122 dns_diff_init(isc_mem_t *mctx, dns_diff_t *diff) {
 123         diff->mctx = mctx;
 124         diff->resign = 0;
 125         ISC_LIST_INIT(diff->tuples);
 126         diff->magic = DNS_DIFF_MAGIC;
 127 }
 128
 129 void
 130 dns_diff_clear(dns_diff_t *diff) {
 131         dns_difftuple_t *t;
 132         REQUIRE(DNS_DIFF_VALID(diff));
 133         while ((t = ISC_LIST_HEAD(diff->tuples)) != NULL) {
 134                 ISC_LIST_UNLINK(diff->tuples, t, link);
 135                 dns_difftuple_free(&t);
 136         }
 137         ENSURE(ISC_LIST_EMPTY(diff->tuples));
 138 }
 139
 140 void
 141 dns_diff_append(dns_diff_t *diff, dns_difftuple_t **tuplep)
 142 {
 143         ISC_LIST_APPEND(diff->tuples, *tuplep, link);
 144         *tuplep = NULL;
 145 }
 146
 147 /* XXX this is O(N) */
 148
 149 void
 150 dns_diff_appendminimal(dns_diff_t *diff, dns_difftuple_t **tuplep)
 151 {
 152         dns_difftuple_t *ot, *next_ot;
 153
 154         REQUIRE(DNS_DIFF_VALID(diff));
 155         REQUIRE(DNS_DIFFTUPLE_VALID(*tuplep));
 156
 157         /*
 158          * Look for an existing tuple with the same owner name,
 159          * rdata, and TTL.   If we are doing an addition and find a
 160          * deletion or vice versa, remove both the old and the
 161          * new tuple since they cancel each other out (assuming
 162          * that we never delete nonexistent data or add existing
 163          * data).
 164          *
 165          * If we find an old update of the same kind as
 166          * the one we are doing, there must be a programming
 167          * error.  We report it but try to continue anyway.
 168          */
 169         for (ot = ISC_LIST_HEAD(diff->tuples); ot != NULL;
 170              ot = next_ot)
 171         {
 172                 next_ot = ISC_LIST_NEXT(ot, link);
 173                 if (dns_name_equal(&ot->name, &(*tuplep)->name) &&
 174                     dns_rdata_compare(&ot->rdata, &(*tuplep)->rdata) == 0 &&
 175                     ot->ttl == (*tuplep)->ttl)
 176                 {
 177                         ISC_LIST_UNLINK(diff->tuples, ot, link);
 178                         if ((*tuplep)->op == ot->op) {
 179                                 UNEXPECTED_ERROR(__FILE__, __LINE__,
 180                                          "unexpected non-minimal diff");
 181                         } else {
 182                                 dns_difftuple_free(tuplep);
 183                         }
 184                         dns_difftuple_free(&ot);
 185                         break;
 186                 }
 187         }
 188
 189         if (*tuplep != NULL) {
 190                 ISC_LIST_APPEND(diff->tuples, *tuplep, link);
 191                 *tuplep = NULL;
 192         }
 193
 194         ENSURE(*tuplep == NULL);
 195 }
 196
 197 static isc_stdtime_t
 198 setresign(dns_rdataset_t *modified, isc_uint32_t delta) {
 199         dns_rdata_t rdata = DNS_RDATA_INIT;
 200         dns_rdata_rrsig_t sig;
 201         isc_stdtime_t when;
 202         isc_result_t result;
 203
 204         result = dns_rdataset_first(modified);
 205         INSIST(result == ISC_R_SUCCESS);
 206         dns_rdataset_current(modified, &rdata);
 207         (void)dns_rdata_tostruct(&rdata, &sig, NULL);
 208         if ((rdata.flags & DNS_RDATA_OFFLINE) != 0)
 209                 when = 0;
 210         else
 211                 when = sig.timeexpire - delta;
 212         dns_rdata_reset(&rdata);
 213
 214         result = dns_rdataset_next(modified);
 215         while (result == ISC_R_SUCCESS) {
 216                 dns_rdataset_current(modified, &rdata);
 217                 (void)dns_rdata_tostruct(&rdata, &sig, NULL);
 218                 if ((rdata.flags & DNS_RDATA_OFFLINE) != 0) {
 219                         goto next_rr;
 220                 }
 221                 if (when == 0 || sig.timeexpire - delta < when)
 222                         when = sig.timeexpire - delta;
 223  next_rr:
 224                 dns_rdata_reset(&rdata);
 225                 result = dns_rdataset_next(modified);
 226         }
 227         INSIST(result == ISC_R_NOMORE);
 228         return (when);
 229 }
 230
 231 static isc_result_t
 232 diff_apply(dns_diff_t *diff, dns_db_t *db, dns_dbversion_t *ver,
 233            isc_boolean_t warn)
 234 {
 235         dns_difftuple_t *t;
 236         dns_dbnode_t *node = NULL;
 237         isc_result_t result;
 238         char namebuf[DNS_NAME_FORMATSIZE];
 239         char typebuf[DNS_RDATATYPE_FORMATSIZE];
 240         char classbuf[DNS_RDATACLASS_FORMATSIZE];
 241
 242         REQUIRE(DNS_DIFF_VALID(diff));
 243         REQUIRE(DNS_DB_VALID(db));
 244
 245         t = ISC_LIST_HEAD(diff->tuples);
 246         while (t != NULL) {
 247                 dns_name_t *name;
 248
 249                 INSIST(node == NULL);
 250                 name = &t->name;
 251                 /*
 252                  * Find the node.
 253                  * We create the node if it does not exist.
 254                  * This will cause an empty node to be created if the diff
 255                  * contains a deletion of an RR at a nonexistent name,
 256                  * but such diffs should never be created in the first
 257                  * place.
 258                  */
 259
 260                 while (t != NULL && dns_name_equal(&t->name, name)) {
 261                         dns_rdatatype_t type, covers;
 262                         dns_diffop_t op;
 263                         dns_rdatalist_t rdl;
 264                         dns_rdataset_t rds;
 265                         dns_rdataset_t ardataset;
 266                         dns_rdataset_t *modified = NULL;
 267                         isc_boolean_t offline;
 268
 269                         op = t->op;
 270                         type = t->rdata.type;
 271                         covers = rdata_covers(&t->rdata);
 272
 273                         /*
 274                          * Collect a contiguous set of updates with
 275                          * the same operation (add/delete) and RR type
 276                          * into a single rdatalist so that the
 277                          * database rrset merging/subtraction code
 278                          * can work more efficiently than if each
 279                          * RR were merged into / subtracted from
 280                          * the database separately.
 281                          *
 282                          * This is done by linking rdata structures from the
 283                          * diff into "rdatalist".  This uses the rdata link
 284                          * field, not the diff link field, so the structure
 285                          * of the diff itself is not affected.
 286                          */
 287
 288                         rdl.type = type;
 289                         rdl.covers = covers;
 290                         rdl.rdclass = t->rdata.rdclass;
 291                         rdl.ttl = t->ttl;
 292                         ISC_LIST_INIT(rdl.rdata);
 293                         ISC_LINK_INIT(&rdl, link);
 294
 295                         node = NULL;
 296                         if (type != dns_rdatatype_nsec3 &&
 297                             covers != dns_rdatatype_nsec3)
 298                                 CHECK(dns_db_findnode(db, name, ISC_TRUE,
 299                                                       &node));
 300                         else
 301                                 CHECK(dns_db_findnsec3node(db, name, ISC_TRUE,
 302                                                            &node));
 303
 304                         offline = ISC_FALSE;
 305                         while (t != NULL &&
 306                                dns_name_equal(&t->name, name) &&
 307                                t->op == op &&
 308                                t->rdata.type == type &&
 309                                rdata_covers(&t->rdata) == covers)
 310                         {
 311                                 dns_name_format(name, namebuf, sizeof(namebuf));
 312                                 dns_rdatatype_format(t->rdata.type, typebuf,
 313                                                      sizeof(typebuf));
 314                                 dns_rdataclass_format(t->rdata.rdclass,
 315                                                       classbuf,
 316                                                       sizeof(classbuf));
 317                                 if (t->ttl != rdl.ttl && warn)
 318                                         isc_log_write(DIFF_COMMON_LOGARGS,
 319                                                 ISC_LOG_WARNING,
 320                                                 "'%s/%s/%s': TTL differs in "
 321                                                 "rdataset, adjusting "
 322                                                 "%lu -> %lu",
 323                                                 namebuf, typebuf, classbuf,
 324                                                 (unsigned long) t->ttl,
 325                                                 (unsigned long) rdl.ttl);
 326                                 if (t->rdata.flags & DNS_RDATA_OFFLINE)
 327                                         offline = ISC_TRUE;
 328                                 ISC_LIST_APPEND(rdl.rdata, &t->rdata, link);
 329                                 t = ISC_LIST_NEXT(t, link);
 330                         }
 331
 332                         /*
 333                          * Convert the rdatalist into a rdataset.
 334                          */
 335                         dns_rdataset_init(&rds);
 336                         CHECK(dns_rdatalist_tordataset(&rdl, &rds));
 337                         if (rds.type == dns_rdatatype_rrsig)
 338                                 switch (op) {
 339                                 case DNS_DIFFOP_ADDRESIGN:
 340                                 case DNS_DIFFOP_DELRESIGN:
 341                                         modified = &ardataset;
 342                                         dns_rdataset_init(modified);
 343                                         break;
 344                                 default:
 345                                         break;
 346                                 }
 347                         rds.trust = dns_trust_ultimate;
 348
 349                         /*
 350                          * Merge the rdataset into the database.
 351                          */
 352                         switch (op) {
 353                         case DNS_DIFFOP_ADD:
 354                         case DNS_DIFFOP_ADDRESIGN:
 355                                 result = dns_db_addrdataset(db, node, ver,
 356                                                             0, &rds,
 357                                                             DNS_DBADD_MERGE|
 358                                                             DNS_DBADD_EXACT|
 359                                                             DNS_DBADD_EXACTTTL,
 360                                                             modified);
 361                                 break;
 362                         case DNS_DIFFOP_DEL:
 363                         case DNS_DIFFOP_DELRESIGN:
 364                                 result = dns_db_subtractrdataset(db, node, ver,
 365                                                                &rds,
 366                                                                DNS_DBSUB_EXACT,
 367                                                                modified);
 368                                 break;
 369                         default:
 370                                 INSIST(0);
 371                         }
 372
 373                         if (result == ISC_R_SUCCESS) {
 374                                 if (modified != NULL) {
 375                                         isc_stdtime_t resign;
 376                                         resign = setresign(modified,
 377                                                            diff->resign);
 378                                         dns_db_setsigningtime(db, modified,
 379                                                               resign);
 380                                 }
 381                         } else if (result == DNS_R_UNCHANGED) {
 382                                 /*
 383                                  * This will not happen when executing a
 384                                  * dynamic update, because that code will
 385                                  * generate strictly minimal diffs.
 386                                  * It may happen when receiving an IXFR
 387                                  * from a server that is not as careful.
 388                                  * Issue a warning and continue.
 389                                  */
 390                                 if (warn)
 391                                         isc_log_write(DIFF_COMMON_LOGARGS,
 392                                                       ISC_LOG_WARNING,
 393                                                       "update with no effect");
 394                         } else if (result == DNS_R_NXRRSET) {
 395                                 /*
 396                                  * OK.
 397                                  */
 398                         } else {
 399                                 if (modified != NULL &&
 400                                     dns_rdataset_isassociated(modified))
 401                                         dns_rdataset_disassociate(modified);
 402                                 CHECK(result);
 403                         }
 404                         dns_db_detachnode(db, &node);
 405                         if (modified != NULL &&
 406                             dns_rdataset_isassociated(modified))
 407                                 dns_rdataset_disassociate(modified);
 408                 }
 409         }
 410         return (ISC_R_SUCCESS);
 411
 412  failure:
 413         if (node != NULL)
 414                 dns_db_detachnode(db, &node);
 415         return (result);
 416 }
 417
 418 isc_result_t
 419 dns_diff_apply(dns_diff_t *diff, dns_db_t *db, dns_dbversion_t *ver) {
 420         return (diff_apply(diff, db, ver, ISC_TRUE));
 421 }
 422
 423 isc_result_t
 424 dns_diff_applysilently(dns_diff_t *diff, dns_db_t *db, dns_dbversion_t *ver) {
 425         return (diff_apply(diff, db, ver, ISC_FALSE));
 426 }
 427
 428 /* XXX this duplicates lots of code in diff_apply(). */
 429
 430 isc_result_t
 431 dns_diff_load(dns_diff_t *diff, dns_addrdatasetfunc_t addfunc,
 432               void *add_private)
 433 {
 434         dns_difftuple_t *t;
 435         isc_result_t result;
 436
 437         REQUIRE(DNS_DIFF_VALID(diff));
 438
 439         t = ISC_LIST_HEAD(diff->tuples);
 440         while (t != NULL) {
 441                 dns_name_t *name;
 442
 443                 name = &t->name;
 444                 while (t != NULL && dns_name_equal(&t->name, name)) {
 445                         dns_rdatatype_t type, covers;
 446                         dns_diffop_t op;
 447                         dns_rdatalist_t rdl;
 448                         dns_rdataset_t rds;
 449
 450                         op = t->op;
 451                         type = t->rdata.type;
 452                         covers = rdata_covers(&t->rdata);
 453
 454                         rdl.type = type;
 455                         rdl.covers = covers;
 456                         rdl.rdclass = t->rdata.rdclass;
 457                         rdl.ttl = t->ttl;
 458                         ISC_LIST_INIT(rdl.rdata);
 459                         ISC_LINK_INIT(&rdl, link);
 460
 461                         while (t != NULL && dns_name_equal(&t->name, name) &&
 462                                t->op == op && t->rdata.type == type &&
 463                                rdata_covers(&t->rdata) == covers)
 464                         {
 465                                 ISC_LIST_APPEND(rdl.rdata, &t->rdata, link);
 466                                 t = ISC_LIST_NEXT(t, link);
 467                         }
 468
 469                         /*
 470                          * Convert the rdatalist into a rdataset.
 471                          */
 472                         dns_rdataset_init(&rds);
 473                         CHECK(dns_rdatalist_tordataset(&rdl, &rds));
 474                         rds.trust = dns_trust_ultimate;
 475
 476                         INSIST(op == DNS_DIFFOP_ADD);
 477                         result = (*addfunc)(add_private, name, &rds);
 478                         if (result == DNS_R_UNCHANGED) {
 479                                 isc_log_write(DIFF_COMMON_LOGARGS,
 480                                               ISC_LOG_WARNING,
 481                                               "update with no effect");
 482                         } else if (result == ISC_R_SUCCESS ||
 483                                    result == DNS_R_NXRRSET) {
 484                                 /*
 485                                  * OK.
 486                                  */
 487                         } else {
 488                                 CHECK(result);
 489                         }
 490                 }
 491         }
 492         result = ISC_R_SUCCESS;
 493  failure:
 494         return (result);
 495 }
 496
 497 /*
 498  * XXX uses qsort(); a merge sort would be more natural for lists,
 499  * and perhaps safer wrt thread stack overflow.
 500  */
 501 isc_result_t
 502 dns_diff_sort(dns_diff_t *diff, dns_diff_compare_func *compare) {
 503         unsigned int length = 0;
 504         unsigned int i;
 505         dns_difftuple_t **v;
 506         dns_difftuple_t *p;
 507         REQUIRE(DNS_DIFF_VALID(diff));
 508
 509         for (p = ISC_LIST_HEAD(diff->tuples);
 510              p != NULL;
 511              p = ISC_LIST_NEXT(p, link))
 512                 length++;
 513         if (length == 0)
 514                 return (ISC_R_SUCCESS);
 515         v = isc_mem_get(diff->mctx, length * sizeof(dns_difftuple_t *));
 516         if (v == NULL)
 517                 return (ISC_R_NOMEMORY);
 518         i = 0;
 519         for (i = 0; i < length; i++) {
 520                 p = ISC_LIST_HEAD(diff->tuples);
 521                 v[i] = p;
 522                 ISC_LIST_UNLINK(diff->tuples, p, link);
 523         }
 524         INSIST(ISC_LIST_HEAD(diff->tuples) == NULL);
 525         qsort(v, length, sizeof(v[0]), compare);
 526         for (i = 0; i < length; i++) {
 527                 ISC_LIST_APPEND(diff->tuples, v[i], link);
 528         }
 529         isc_mem_put(diff->mctx, v, length * sizeof(dns_difftuple_t *));
 530         return (ISC_R_SUCCESS);
 531 }
 532
 533
 534 /*
 535  * Create an rdataset containing the single RR of the given
 536  * tuple.  The caller must allocate the rdata, rdataset and
 537  * an rdatalist structure for it to refer to.
 538  */
 539
 540 static isc_result_t
 541 diff_tuple_tordataset(dns_difftuple_t *t, dns_rdata_t *rdata,
 542                       dns_rdatalist_t *rdl, dns_rdataset_t *rds)
 543 {
 544         REQUIRE(DNS_DIFFTUPLE_VALID(t));
 545         REQUIRE(rdl != NULL);
 546         REQUIRE(rds != NULL);
 547
 548         rdl->type = t->rdata.type;
 549         rdl->rdclass = t->rdata.rdclass;
 550         rdl->ttl = t->ttl;
 551         ISC_LIST_INIT(rdl->rdata);
 552         ISC_LINK_INIT(rdl, link);
 553         dns_rdataset_init(rds);
 554         ISC_LINK_INIT(rdata, link);
 555         dns_rdata_clone(&t->rdata, rdata);
 556         ISC_LIST_APPEND(rdl->rdata, rdata, link);
 557         return (dns_rdatalist_tordataset(rdl, rds));
 558 }
 559
 560 isc_result_t
 561 dns_diff_print(dns_diff_t *diff, FILE *file) {
 562         isc_result_t result;
 563         dns_difftuple_t *t;
 564         char *mem = NULL;
 565         unsigned int size = 2048;
 566         const char *op = NULL;
 567
 568         REQUIRE(DNS_DIFF_VALID(diff));
 569
 570         mem = isc_mem_get(diff->mctx, size);
 571         if (mem == NULL)
 572                 return (ISC_R_NOMEMORY);
 573
 574         for (t = ISC_LIST_HEAD(diff->tuples); t != NULL;
 575              t = ISC_LIST_NEXT(t, link))
 576         {
 577                 isc_buffer_t buf;
 578                 isc_region_t r;
 579
 580                 dns_rdatalist_t rdl;
 581                 dns_rdataset_t rds;
 582                 dns_rdata_t rd = DNS_RDATA_INIT;
 583
 584                 result = diff_tuple_tordataset(t, &rd, &rdl, &rds);
 585                 if (result != ISC_R_SUCCESS) {
 586                         UNEXPECTED_ERROR(__FILE__, __LINE__,
 587                                          "diff_tuple_tordataset failed: %s",
 588                                          dns_result_totext(result));
 589                         result =  ISC_R_UNEXPECTED;
 590                         goto cleanup;
 591                 }
 592  again:
 593                 isc_buffer_init(&buf, mem, size);
 594                 result = dns_rdataset_totext(&rds, &t->name,
 595                                              ISC_FALSE, ISC_FALSE, &buf);
 596
 597                 if (result == ISC_R_NOSPACE) {
 598                         isc_mem_put(diff->mctx, mem, size);
 599                         size += 1024;
 600                         mem = isc_mem_get(diff->mctx, size);
 601                         if (mem == NULL) {
 602                                 result = ISC_R_NOMEMORY;
 603                                 goto cleanup;
 604                         }
 605                         goto again;
 606                 }
 607
 608                 if (result != ISC_R_SUCCESS)
 609                         goto cleanup;
 610                 /*
 611                  * Get rid of final newline.
 612                  */
 613                 INSIST(buf.used >= 1 &&
 614                        ((char *) buf.base)[buf.used-1] == '\n');
 615                 buf.used--;
 616
 617                 isc_buffer_usedregion(&buf, &r);
 618                 switch (t->op) {
 619                 case DNS_DIFFOP_EXISTS: op = "exists"; break;
 620                 case DNS_DIFFOP_ADD: op = "add"; break;
 621                 case DNS_DIFFOP_DEL: op = "del"; break;
 622                 case DNS_DIFFOP_ADDRESIGN: op = "add re-sign"; break;
 623                 case DNS_DIFFOP_DELRESIGN: op = "del re-sign"; break;
 624                 }
 625                 if (file != NULL)
 626                         fprintf(file, "%s %.*s\n", op, (int) r.length,
 627                                 (char *) r.base);
 628                 else
 629                         isc_log_write(DIFF_COMMON_LOGARGS, ISC_LOG_DEBUG(7),
 630                                       "%s %.*s", op, (int) r.length,
 631                                       (char *) r.base);
 632         }
 633         result = ISC_R_SUCCESS;
 634  cleanup:
 635         if (mem != NULL)
 636                 isc_mem_put(diff->mctx, mem, size);
 637         return (result);
 638 }