lib/pack.c

   1 /*
   2  * Copyright (c) 2018, 2019, 2020 Stefan Sperling <stsp@openbsd.org>
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16
  17 #include <sys/types.h>
  18 #include <sys/stat.h>
  19 #include <sys/uio.h>
  20 #include <sys/mman.h>
  21
  22 #include <fcntl.h>
  23 #include <errno.h>
  24 #include <stdio.h>
  25 #include <stdint.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <limits.h>
  29 #include <unistd.h>
  30 #include <zlib.h>
  31
  32 #include "got_error.h"
  33 #include "got_object.h"
  34 #include "got_opentemp.h"
  35 #include "got_path.h"
  36
  37 #include "got_lib_sha1.h"
  38 #include "got_lib_delta.h"
  39 #include "got_lib_delta_cache.h"
  40 #include "got_lib_inflate.h"
  41 #include "got_lib_object.h"
  42 #include "got_lib_object_parse.h"
  43 #include "got_lib_privsep.h"
  44 #include "got_lib_pack.h"
  45
  46 #ifndef nitems
  47 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
  48 #endif
  49
  50 #ifndef MIN
  51 #define MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
  52 #endif
  53
  54 static const struct got_error *
  55 verify_fanout_table(uint32_t *fanout_table)
  56 {
  57         int i;
  58
  59         for (i = 0; i < 0xff - 1; i++) {
  60                 if (be32toh(fanout_table[i]) > be32toh(fanout_table[i + 1]))
  61                         return got_error(GOT_ERR_BAD_PACKIDX);
  62         }
  63
  64         return NULL;
  65 }
  66
  67 const struct got_error *
  68 got_packidx_init_hdr(struct got_packidx *p, int verify, off_t packfile_size)
  69 {
  70         const struct got_error *err = NULL;
  71         struct got_packidx_v2_hdr *h;
  72         SHA1_CTX ctx;
  73         uint8_t sha1[SHA1_DIGEST_LENGTH];
  74         size_t nobj, len_fanout, len_ids, offset, remain;
  75         ssize_t n;
  76         int i;
  77
  78         SHA1Init(&ctx);
  79
  80         h = &p->hdr;
  81         offset = 0;
  82         remain = p->len;
  83
  84         if (remain < sizeof(*h->magic)) {
  85                 err = got_error(GOT_ERR_BAD_PACKIDX);
  86                 goto done;
  87         }
  88         if (p->map)
  89                 h->magic = (uint32_t *)(p->map + offset);
  90         else {
  91                 h->magic = malloc(sizeof(*h->magic));
  92                 if (h->magic == NULL) {
  93                         err = got_error_from_errno("malloc");
  94                         goto done;
  95                 }
  96                 n = read(p->fd, h->magic, sizeof(*h->magic));
  97                 if (n < 0) {
  98                         err = got_error_from_errno("read");
  99                         goto done;
 100                 } else if (n != sizeof(*h->magic)) {
 101                         err = got_error(GOT_ERR_BAD_PACKIDX);
 102                         goto done;
 103                 }
 104         }
 105         if (*h->magic != htobe32(GOT_PACKIDX_V2_MAGIC)) {
 106                 err = got_error(GOT_ERR_BAD_PACKIDX);
 107                 goto done;
 108         }
 109         offset += sizeof(*h->magic);
 110         remain -= sizeof(*h->magic);
 111
 112         if (verify)
 113                 SHA1Update(&ctx, (uint8_t *)h->magic, sizeof(*h->magic));
 114
 115         if (remain < sizeof(*h->version)) {
 116                 err = got_error(GOT_ERR_BAD_PACKIDX);
 117                 goto done;
 118         }
 119         if (p->map)
 120                 h->version = (uint32_t *)(p->map + offset);
 121         else {
 122                 h->version = malloc(sizeof(*h->version));
 123                 if (h->version == NULL) {
 124                         err = got_error_from_errno("malloc");
 125                         goto done;
 126                 }
 127                 n = read(p->fd, h->version, sizeof(*h->version));
 128                 if (n < 0) {
 129                         err = got_error_from_errno("read");
 130                         goto done;
 131                 } else if (n != sizeof(*h->version)) {
 132                         err = got_error(GOT_ERR_BAD_PACKIDX);
 133                         goto done;
 134                 }
 135         }
 136         if (*h->version != htobe32(GOT_PACKIDX_VERSION)) {
 137                 err = got_error(GOT_ERR_BAD_PACKIDX);
 138                 goto done;
 139         }
 140         offset += sizeof(*h->version);
 141         remain -= sizeof(*h->version);
 142
 143         if (verify)
 144                 SHA1Update(&ctx, (uint8_t *)h->version, sizeof(*h->version));
 145
 146         len_fanout =
 147             sizeof(*h->fanout_table) * GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS;
 148         if (remain < len_fanout) {
 149                 err = got_error(GOT_ERR_BAD_PACKIDX);
 150                 goto done;
 151         }
 152         if (p->map)
 153                 h->fanout_table = (uint32_t *)(p->map + offset);
 154         else {
 155                 h->fanout_table = malloc(len_fanout);
 156                 if (h->fanout_table == NULL) {
 157                         err = got_error_from_errno("malloc");
 158                         goto done;
 159                 }
 160                 n = read(p->fd, h->fanout_table, len_fanout);
 161                 if (n < 0) {
 162                         err = got_error_from_errno("read");
 163                         goto done;
 164                 } else if (n != len_fanout) {
 165                         err = got_error(GOT_ERR_BAD_PACKIDX);
 166                         goto done;
 167                 }
 168         }
 169         err = verify_fanout_table(h->fanout_table);
 170         if (err)
 171                 goto done;
 172         if (verify)
 173                 SHA1Update(&ctx, (uint8_t *)h->fanout_table, len_fanout);
 174         offset += len_fanout;
 175         remain -= len_fanout;
 176
 177         nobj = be32toh(h->fanout_table[0xff]);
 178         len_ids = nobj * sizeof(*h->sorted_ids);
 179         if (len_ids <= nobj || len_ids > remain) {
 180                 err = got_error(GOT_ERR_BAD_PACKIDX);
 181                 goto done;
 182         }
 183         if (p->map)
 184                 h->sorted_ids =
 185                     (struct got_packidx_object_id *)((uint8_t*)(p->map + offset));
 186         else {
 187                 h->sorted_ids = malloc(len_ids);
 188                 if (h->sorted_ids == NULL) {
 189                         err = got_error(GOT_ERR_BAD_PACKIDX);
 190                         goto done;
 191                 }
 192                 n = read(p->fd, h->sorted_ids, len_ids);
 193                 if (n < 0)
 194                         err = got_error_from_errno("read");
 195                 else if (n != len_ids) {
 196                         err = got_error(GOT_ERR_BAD_PACKIDX);
 197                         goto done;
 198                 }
 199         }
 200         if (verify)
 201                 SHA1Update(&ctx, (uint8_t *)h->sorted_ids, len_ids);
 202         offset += len_ids;
 203         remain -= len_ids;
 204
 205         if (remain < nobj * sizeof(*h->crc32)) {
 206                 err = got_error(GOT_ERR_BAD_PACKIDX);
 207                 goto done;
 208         }
 209         if (p->map)
 210                 h->crc32 = (uint32_t *)((uint8_t*)(p->map + offset));
 211         else {
 212                 h->crc32 = malloc(nobj * sizeof(*h->crc32));
 213                 if (h->crc32 == NULL) {
 214                         err = got_error_from_errno("malloc");
 215                         goto done;
 216                 }
 217                 n = read(p->fd, h->crc32, nobj * sizeof(*h->crc32));
 218                 if (n < 0)
 219                         err = got_error_from_errno("read");
 220                 else if (n != nobj * sizeof(*h->crc32)) {
 221                         err = got_error(GOT_ERR_BAD_PACKIDX);
 222                         goto done;
 223                 }
 224         }
 225         if (verify)
 226                 SHA1Update(&ctx, (uint8_t *)h->crc32, nobj * sizeof(*h->crc32));
 227         remain -= nobj * sizeof(*h->crc32);
 228         offset += nobj * sizeof(*h->crc32);
 229
 230         if (remain < nobj * sizeof(*h->offsets)) {
 231                 err = got_error(GOT_ERR_BAD_PACKIDX);
 232                 goto done;
 233         }
 234         if (p->map)
 235                 h->offsets = (uint32_t *)((uint8_t*)(p->map + offset));
 236         else {
 237                 h->offsets = malloc(nobj * sizeof(*h->offsets));
 238                 if (h->offsets == NULL) {
 239                         err = got_error_from_errno("malloc");
 240                         goto done;
 241                 }
 242                 n = read(p->fd, h->offsets, nobj * sizeof(*h->offsets));
 243                 if (n < 0)
 244                         err = got_error_from_errno("read");
 245                 else if (n != nobj * sizeof(*h->offsets)) {
 246                         err = got_error(GOT_ERR_BAD_PACKIDX);
 247                         goto done;
 248                 }
 249         }
 250         if (verify)
 251                 SHA1Update(&ctx, (uint8_t *)h->offsets,
 252                     nobj * sizeof(*h->offsets));
 253         remain -= nobj * sizeof(*h->offsets);
 254         offset += nobj * sizeof(*h->offsets);
 255
 256         /* Large file offsets are contained only in files > 2GB. */
 257         if (verify || packfile_size > 0x7fffffff) {
 258                 for (i = 0; i < nobj; i++) {
 259                         uint32_t o = h->offsets[i];
 260                         if (o & htobe32(GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX))
 261                                 p->nlargeobj++;
 262                 }
 263         }
 264         if (p->nlargeobj == 0)
 265                 goto checksum;
 266         else if (packfile_size <= 0x7fffffff) {
 267                 err = got_error(GOT_ERR_BAD_PACKIDX);
 268                 goto done;
 269         }
 270
 271         if (remain < p->nlargeobj * sizeof(*h->large_offsets)) {
 272                 err = got_error(GOT_ERR_BAD_PACKIDX);
 273                 goto done;
 274         }
 275         if (p->map)
 276                 h->large_offsets = (uint64_t *)((uint8_t*)(p->map + offset));
 277         else {
 278                 h->large_offsets = malloc(p->nlargeobj *
 279                     sizeof(*h->large_offsets));
 280                 if (h->large_offsets == NULL) {
 281                         err = got_error_from_errno("malloc");
 282                         goto done;
 283                 }
 284                 n = read(p->fd, h->large_offsets,
 285                     p->nlargeobj * sizeof(*h->large_offsets));
 286                 if (n < 0)
 287                         err = got_error_from_errno("read");
 288                 else if (n != p->nlargeobj * sizeof(*h->large_offsets)) {
 289                         err = got_error(GOT_ERR_BAD_PACKIDX);
 290                         goto done;
 291                 }
 292         }
 293         if (verify)
 294                 SHA1Update(&ctx, (uint8_t*)h->large_offsets,
 295                     p->nlargeobj * sizeof(*h->large_offsets));
 296         remain -= p->nlargeobj * sizeof(*h->large_offsets);
 297         offset += p->nlargeobj * sizeof(*h->large_offsets);
 298
 299 checksum:
 300         if (remain < sizeof(*h->trailer)) {
 301                 err = got_error(GOT_ERR_BAD_PACKIDX);
 302                 goto done;
 303         }
 304         if (p->map)
 305                 h->trailer =
 306                     (struct got_packidx_trailer *)((uint8_t*)(p->map + offset));
 307         else {
 308                 h->trailer = malloc(sizeof(*h->trailer));
 309                 if (h->trailer == NULL) {
 310                         err = got_error_from_errno("malloc");
 311                         goto done;
 312                 }
 313                 n = read(p->fd, h->trailer, sizeof(*h->trailer));
 314                 if (n < 0)
 315                         err = got_error_from_errno("read");
 316                 else if (n != sizeof(*h->trailer)) {
 317                         err = got_error(GOT_ERR_BAD_PACKIDX);
 318                         goto done;
 319                 }
 320         }
 321         if (verify) {
 322                 SHA1Update(&ctx, h->trailer->packfile_sha1, SHA1_DIGEST_LENGTH);
 323                 SHA1Final(sha1, &ctx);
 324                 if (memcmp(h->trailer->packidx_sha1, sha1,
 325                     SHA1_DIGEST_LENGTH) != 0)
 326                         err = got_error(GOT_ERR_PACKIDX_CSUM);
 327         }
 328 done:
 329         return err;
 330 }
 331
 332 const struct got_error *
 333 got_packidx_open(struct got_packidx **packidx,
 334     int dir_fd, const char *relpath, int verify)
 335 {
 336         const struct got_error *err = NULL;
 337         struct got_packidx *p = NULL;
 338         char *pack_relpath;
 339         struct stat idx_sb, pack_sb;
 340
 341         *packidx = NULL;
 342
 343         err = got_packidx_get_packfile_path(&pack_relpath, relpath);
 344         if (err)
 345                 return err;
 346
 347         /*
 348          * Ensure that a corresponding pack file exists.
 349          * Some Git repositories have this problem. Git seems to ignore
 350          * the existence of lonely pack index files but we do not.
 351          */
 352         if (fstatat(dir_fd, pack_relpath, &pack_sb, 0) == -1) {
 353                 if (errno == ENOENT) {
 354                         err = got_error_fmt(GOT_ERR_LONELY_PACKIDX,
 355                             "%s", relpath);
 356                 } else
 357                         err = got_error_from_errno2("fstatat", pack_relpath);
 358                 goto done;
 359         }
 360
 361         p = calloc(1, sizeof(*p));
 362         if (p == NULL) {
 363                 err = got_error_from_errno("calloc");
 364                 goto done;
 365         }
 366
 367         p->fd = openat(dir_fd, relpath, O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
 368         if (p->fd == -1) {
 369                 err = got_error_from_errno2("openat", relpath);
 370                 free(p);
 371                 goto done;
 372         }
 373
 374         if (fstat(p->fd, &idx_sb) != 0) {
 375                 err = got_error_from_errno2("fstat", relpath);
 376                 close(p->fd);
 377                 free(p);
 378                 goto done;
 379         }
 380         p->len = idx_sb.st_size;
 381         if (p->len < sizeof(p->hdr)) {
 382                 err = got_error(GOT_ERR_BAD_PACKIDX);
 383                 close(p->fd);
 384                 free(p);
 385                 goto done;
 386         }
 387
 388         p->path_packidx = strdup(relpath);
 389         if (p->path_packidx == NULL) {
 390                 err = got_error_from_errno("strdup");
 391                 goto done;
 392         }
 393
 394 #ifndef GOT_PACK_NO_MMAP
 395         p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
 396         if (p->map == MAP_FAILED) {
 397                 if (errno != ENOMEM) {
 398                         err = got_error_from_errno("mmap");
 399                         goto done;
 400                 }
 401                 p->map = NULL; /* fall back to read(2) */
 402         }
 403 #endif
 404
 405         err = got_packidx_init_hdr(p, verify, pack_sb.st_size);
 406 done:
 407         if (err) {
 408                 if (p)
 409                         got_packidx_close(p);
 410         } else
 411                 *packidx = p;
 412         free(pack_relpath);
 413         return err;
 414 }
 415
 416 const struct got_error *
 417 got_packidx_close(struct got_packidx *packidx)
 418 {
 419         const struct got_error *err = NULL;
 420
 421         free(packidx->path_packidx);
 422         if (packidx->map) {
 423                 if (munmap(packidx->map, packidx->len) == -1)
 424                         err = got_error_from_errno("munmap");
 425         } else {
 426                 free(packidx->hdr.magic);
 427                 free(packidx->hdr.version);
 428                 free(packidx->hdr.fanout_table);
 429                 free(packidx->hdr.sorted_ids);
 430                 free(packidx->hdr.crc32);
 431                 free(packidx->hdr.offsets);
 432                 free(packidx->hdr.large_offsets);
 433                 free(packidx->hdr.trailer);
 434         }
 435         if (close(packidx->fd) == -1 && err == NULL)
 436                 err = got_error_from_errno("close");
 437         free(packidx);
 438
 439         return err;
 440 }
 441
 442 const struct got_error *
 443 got_packidx_get_packfile_path(char **path_packfile, const char *path_packidx)
 444 {
 445         size_t size;
 446
 447         /* Packfile path contains ".pack" instead of ".idx", so add one byte. */
 448         size = strlen(path_packidx) + 2;
 449         if (size < GOT_PACKFILE_NAMELEN + 1)
 450                 return got_error_path(path_packidx, GOT_ERR_BAD_PATH);
 451
 452         *path_packfile = malloc(size);
 453         if (*path_packfile == NULL)
 454                 return got_error_from_errno("malloc");
 455
 456         /* Copy up to and excluding ".idx". */
 457         if (strlcpy(*path_packfile, path_packidx,
 458             size - strlen(GOT_PACKIDX_SUFFIX) - 1) >= size)
 459                 return got_error(GOT_ERR_NO_SPACE);
 460
 461         if (strlcat(*path_packfile, GOT_PACKFILE_SUFFIX, size) >= size)
 462                 return got_error(GOT_ERR_NO_SPACE);
 463
 464         return NULL;
 465 }
 466
 467 off_t
 468 got_packidx_get_object_offset(struct got_packidx *packidx, int idx)
 469 {
 470         uint32_t offset = be32toh(packidx->hdr.offsets[idx]);
 471         if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
 472                 uint64_t loffset;
 473                 idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
 474                 if (idx < 0 || idx >= packidx->nlargeobj ||
 475                     packidx->hdr.large_offsets == NULL)
 476                         return -1;
 477                 loffset = be64toh(packidx->hdr.large_offsets[idx]);
 478                 return (loffset > INT64_MAX ? -1 : (off_t)loffset);
 479         }
 480         return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
 481 }
 482
 483 int
 484 got_packidx_get_object_idx(struct got_packidx *packidx,
 485     struct got_object_id *id)
 486 {
 487         u_int8_t id0 = id->sha1[0];
 488         uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
 489         int left = 0, right = totobj - 1;
 490
 491         if (id0 > 0)
 492                 left = be32toh(packidx->hdr.fanout_table[id0 - 1]);
 493
 494         while (left <= right) {
 495                 struct got_packidx_object_id *oid;
 496                 int i, cmp;
 497
 498                 i = ((left + right) / 2);
 499                 oid = &packidx->hdr.sorted_ids[i];
 500                 cmp = memcmp(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
 501                 if (cmp == 0)
 502                         return i;
 503                 else if (cmp > 0)
 504                         left = i + 1;
 505                 else if (cmp < 0)
 506                         right = i - 1;
 507         }
 508
 509         return -1;
 510 }
 511
 512 const struct got_error *
 513 got_packidx_match_id_str_prefix(struct got_object_id_queue *matched_ids,
 514     struct got_packidx *packidx, const char *id_str_prefix)
 515 {
 516         const struct got_error *err = NULL;
 517         u_int8_t id0;
 518         uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
 519         char hex[3];
 520         size_t prefix_len = strlen(id_str_prefix);
 521         struct got_packidx_object_id *oid;
 522         uint32_t i = 0;
 523
 524         STAILQ_INIT(matched_ids);
 525
 526         if (prefix_len < 2)
 527                 return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
 528
 529         hex[0] = id_str_prefix[0];
 530         hex[1] = id_str_prefix[1];
 531         hex[2] = '\0';
 532         if (!got_parse_xdigit(&id0, hex))
 533                 return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
 534
 535         if (id0 > 0)
 536                 i = be32toh(packidx->hdr.fanout_table[id0 - 1]);
 537         oid = &packidx->hdr.sorted_ids[i];
 538         while (i < totobj && oid->sha1[0] == id0) {
 539                 char id_str[SHA1_DIGEST_STRING_LENGTH];
 540                 struct got_object_qid *qid;
 541                 int cmp;
 542
 543                 if (!got_sha1_digest_to_str(oid->sha1, id_str, sizeof(id_str)))
 544                         return got_error(GOT_ERR_NO_SPACE);
 545
 546                 cmp = strncmp(id_str, id_str_prefix, prefix_len);
 547                 if (cmp < 0) {
 548                         oid = &packidx->hdr.sorted_ids[++i];
 549                         continue;
 550                 } else if (cmp > 0)
 551                         break;
 552
 553                 err = got_object_qid_alloc_partial(&qid);
 554                 if (err)
 555                         break;
 556                 memcpy(qid->id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
 557                 STAILQ_INSERT_TAIL(matched_ids, qid, entry);
 558
 559                 oid = &packidx->hdr.sorted_ids[++i];
 560         }
 561
 562         if (err)
 563                 got_object_id_queue_free(matched_ids);
 564         return err;
 565 }
 566
 567 static const struct got_error *
 568 pack_stop_privsep_child(struct got_pack *pack)
 569 {
 570         const struct got_error *err = NULL;
 571
 572         if (pack->privsep_child == NULL)
 573                 return NULL;
 574
 575         err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
 576         if (err)
 577                 return err;
 578         err = got_privsep_wait_for_child(pack->privsep_child->pid);
 579         if (close(pack->privsep_child->imsg_fd) == -1 && err == NULL)
 580                 err = got_error_from_errno("close");
 581         imsg_clear(pack->privsep_child->ibuf);
 582         free(pack->privsep_child->ibuf);
 583         free(pack->privsep_child);
 584         pack->privsep_child = NULL;
 585         return err;
 586 }
 587
 588 const struct got_error *
 589 got_pack_close(struct got_pack *pack)
 590 {
 591         const struct got_error *err = NULL;
 592
 593         err = pack_stop_privsep_child(pack);
 594         if (pack->map && munmap(pack->map, pack->filesize) == -1 && !err)
 595                 err = got_error_from_errno("munmap");
 596         if (pack->fd != -1 && close(pack->fd) == -1 && err == NULL)
 597                 err = got_error_from_errno("close");
 598         pack->fd = -1;
 599         free(pack->path_packfile);
 600         pack->path_packfile = NULL;
 601         pack->filesize = 0;
 602         if (pack->delta_cache) {
 603                 got_delta_cache_free(pack->delta_cache);
 604                 pack->delta_cache = NULL;
 605         }
 606
 607         return err;
 608 }
 609
 610 const struct got_error *
 611 got_pack_parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
 612     struct got_pack *pack, off_t offset)
 613 {
 614         uint8_t t = 0;
 615         uint64_t s = 0;
 616         uint8_t sizeN;
 617         size_t mapoff = 0;
 618         int i = 0;
 619
 620         *len = 0;
 621
 622         if (offset >= pack->filesize)
 623                 return got_error(GOT_ERR_PACK_OFFSET);
 624
 625         if (pack->map) {
 626                 mapoff = (size_t)offset;
 627         } else {
 628                 if (lseek(pack->fd, offset, SEEK_SET) == -1)
 629                         return got_error_from_errno("lseek");
 630         }
 631
 632         do {
 633                 /* We do not support size values which don't fit in 64 bit. */
 634                 if (i > 9)
 635                         return got_error(GOT_ERR_NO_SPACE);
 636
 637                 if (pack->map) {
 638                         if (mapoff + sizeof(sizeN) >= pack->filesize)
 639                                 return got_error(GOT_ERR_BAD_PACKFILE);
 640                         sizeN = *(pack->map + mapoff);
 641                         mapoff += sizeof(sizeN);
 642                 } else {
 643                         ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
 644                         if (n < 0)
 645                                 return got_error_from_errno("read");
 646                         if (n != sizeof(sizeN))
 647                                 return got_error(GOT_ERR_BAD_PACKFILE);
 648                 }
 649                 *len += sizeof(sizeN);
 650
 651                 if (i == 0) {
 652                         t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
 653                             GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
 654                         s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
 655                 } else {
 656                         size_t shift = 4 + 7 * (i - 1);
 657                         s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
 658                 }
 659                 i++;
 660         } while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
 661
 662         *type = t;
 663         *size = s;
 664         return NULL;
 665 }
 666
 667 static const struct got_error *
 668 open_plain_object(struct got_object **obj, struct got_object_id *id,
 669     uint8_t type, off_t offset, size_t size, int idx)
 670 {
 671         *obj = calloc(1, sizeof(**obj));
 672         if (*obj == NULL)
 673                 return got_error_from_errno("calloc");
 674
 675         (*obj)->type = type;
 676         (*obj)->flags = GOT_OBJ_FLAG_PACKED;
 677         (*obj)->pack_idx = idx;
 678         (*obj)->hdrlen = 0;
 679         (*obj)->size = size;
 680         memcpy(&(*obj)->id, id, sizeof((*obj)->id));
 681         (*obj)->pack_offset = offset;
 682
 683         return NULL;
 684 }
 685
 686 static const struct got_error *
 687 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
 688     off_t delta_offset)
 689 {
 690         int64_t o = 0;
 691         uint8_t offN;
 692         int i = 0;
 693
 694         *offset = 0;
 695         *len = 0;
 696
 697         do {
 698                 /* We do not support offset values which don't fit in 64 bit. */
 699                 if (i > 8)
 700                         return got_error(GOT_ERR_NO_SPACE);
 701
 702                 if (pack->map) {
 703                         size_t mapoff;
 704                         mapoff = (size_t)delta_offset + *len;
 705                         if (mapoff + sizeof(offN) >= pack->filesize)
 706                                 return got_error(GOT_ERR_PACK_OFFSET);
 707                         offN = *(pack->map + mapoff);
 708                 } else {
 709                         ssize_t n;
 710                         n = read(pack->fd, &offN, sizeof(offN));
 711                         if (n < 0)
 712                                 return got_error_from_errno("read");
 713                         if (n != sizeof(offN))
 714                                 return got_error(GOT_ERR_BAD_PACKFILE);
 715                 }
 716                 *len += sizeof(offN);
 717
 718                 if (i == 0)
 719                         o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
 720                 else {
 721                         o++;
 722                         o <<= 7;
 723                         o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
 724                 }
 725                 i++;
 726         } while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
 727
 728         *offset = o;
 729         return NULL;
 730 }
 731
 732 const struct got_error *
 733 got_pack_parse_offset_delta(off_t *base_offset, size_t *len,
 734     struct got_pack *pack, off_t offset, int tslen)
 735 {
 736         const struct got_error *err;
 737         int64_t negoffset;
 738         size_t negofflen;
 739
 740         *len = 0;
 741
 742         err = parse_negative_offset(&negoffset, &negofflen, pack,
 743             offset + tslen);
 744         if (err)
 745                 return err;
 746
 747         /* Compute the base object's offset (must be in the same pack file). */
 748         *base_offset = (offset - negoffset);
 749         if (*base_offset <= 0)
 750                 return got_error(GOT_ERR_BAD_PACKFILE);
 751
 752         *len = negofflen;
 753         return NULL;
 754 }
 755
 756 static const struct got_error *
 757 read_delta_data(uint8_t **delta_buf, size_t *delta_len,
 758     size_t delta_data_offset, struct got_pack *pack)
 759 {
 760         const struct got_error *err = NULL;
 761
 762         if (pack->map) {
 763                 if (delta_data_offset >= pack->filesize)
 764                         return got_error(GOT_ERR_PACK_OFFSET);
 765                 err = got_inflate_to_mem_mmap(delta_buf, delta_len,
 766                     NULL, NULL, pack->map, delta_data_offset,
 767                     pack->filesize - delta_data_offset);
 768         } else {
 769                 if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1)
 770                         return got_error_from_errno("lseek");
 771                 err = got_inflate_to_mem_fd(delta_buf, delta_len, NULL,
 772                     NULL, 0, pack->fd);
 773         }
 774         return err;
 775 }
 776
 777 static const struct got_error *
 778 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
 779     int delta_type, size_t delta_size, size_t delta_data_offset)
 780 {
 781         struct got_delta *delta;
 782
 783         delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
 784             delta_data_offset);
 785         if (delta == NULL)
 786                 return got_error_from_errno("got_delta_open");
 787         /* delta is freed in got_object_close() */
 788         deltas->nentries++;
 789         STAILQ_INSERT_HEAD(&deltas->entries, delta, entry);
 790         return NULL;
 791 }
 792
 793 static const struct got_error *
 794 resolve_offset_delta(struct got_delta_chain *deltas,
 795     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
 796     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
 797
 798 {
 799         const struct got_error *err;
 800         off_t base_offset;
 801         uint8_t base_type;
 802         uint64_t base_size;
 803         size_t base_tslen;
 804         off_t delta_data_offset;
 805         size_t consumed;
 806
 807         err = got_pack_parse_offset_delta(&base_offset, &consumed, pack,
 808             delta_offset, tslen);
 809         if (err)
 810                 return err;
 811
 812         delta_data_offset = delta_offset + tslen + consumed;
 813         if (delta_data_offset >= pack->filesize)
 814                 return got_error(GOT_ERR_PACK_OFFSET);
 815
 816         if (pack->map == NULL) {
 817                 delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
 818                 if (delta_data_offset == -1)
 819                         return got_error_from_errno("lseek");
 820         }
 821
 822         err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
 823             delta_data_offset);
 824         if (err)
 825                 return err;
 826
 827         /* An offset delta must be in the same packfile. */
 828         if (base_offset >= pack->filesize)
 829                 return got_error(GOT_ERR_PACK_OFFSET);
 830
 831         err = got_pack_parse_object_type_and_size(&base_type, &base_size,
 832             &base_tslen, pack, base_offset);
 833         if (err)
 834                 return err;
 835
 836         return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
 837             base_tslen, base_type, base_size, recursion - 1);
 838 }
 839
 840 const struct got_error *
 841 got_pack_parse_ref_delta(struct got_object_id *id,
 842     struct got_pack *pack, off_t delta_offset, int tslen)
 843 {
 844         if (pack->map) {
 845                 size_t mapoff = delta_offset + tslen;
 846                 if (mapoff + sizeof(*id) >= pack->filesize)
 847                         return got_error(GOT_ERR_PACK_OFFSET);
 848                 memcpy(id, pack->map + mapoff, sizeof(*id));
 849         } else {
 850                 ssize_t n;
 851                 n = read(pack->fd, id, sizeof(*id));
 852                 if (n < 0)
 853                         return got_error_from_errno("read");
 854                 if (n != sizeof(*id))
 855                         return got_error(GOT_ERR_BAD_PACKFILE);
 856         }
 857
 858         return NULL;
 859 }
 860
 861 static const struct got_error *
 862 resolve_ref_delta(struct got_delta_chain *deltas, struct got_packidx *packidx,
 863     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
 864     size_t delta_size, unsigned int recursion)
 865 {
 866         const struct got_error *err;
 867         struct got_object_id id;
 868         int idx;
 869         off_t base_offset;
 870         uint8_t base_type;
 871         uint64_t base_size;
 872         size_t base_tslen;
 873         off_t delta_data_offset;
 874
 875         if (delta_offset + tslen >= pack->filesize)
 876                 return got_error(GOT_ERR_PACK_OFFSET);
 877
 878         err = got_pack_parse_ref_delta(&id, pack, delta_offset, tslen);
 879         if (err)
 880                 return err;
 881         if (pack->map) {
 882                 delta_data_offset = delta_offset + tslen + sizeof(id);
 883         } else {
 884                 delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
 885                 if (delta_data_offset == -1)
 886                         return got_error_from_errno("lseek");
 887         }
 888
 889         err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
 890             delta_data_offset);
 891         if (err)
 892                 return err;
 893
 894         /* Delta base must be in the same pack file. */
 895         idx = got_packidx_get_object_idx(packidx, &id);
 896         if (idx == -1)
 897                 return got_error(GOT_ERR_NO_OBJ);
 898
 899         base_offset = got_packidx_get_object_offset(packidx, idx);
 900         if (base_offset == (uint64_t)-1)
 901                 return got_error(GOT_ERR_BAD_PACKIDX);
 902
 903         if (base_offset >= pack->filesize)
 904                 return got_error(GOT_ERR_PACK_OFFSET);
 905
 906         err = got_pack_parse_object_type_and_size(&base_type, &base_size,
 907             &base_tslen, pack, base_offset);
 908         if (err)
 909                 return err;
 910
 911         return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
 912             base_tslen, base_type, base_size, recursion - 1);
 913 }
 914
 915 const struct got_error *
 916 got_pack_resolve_delta_chain(struct got_delta_chain *deltas,
 917     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
 918     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
 919 {
 920         const struct got_error *err = NULL;
 921
 922         if (--recursion == 0)
 923                 return got_error(GOT_ERR_RECURSION);
 924
 925         switch (delta_type) {
 926         case GOT_OBJ_TYPE_COMMIT:
 927         case GOT_OBJ_TYPE_TREE:
 928         case GOT_OBJ_TYPE_BLOB:
 929         case GOT_OBJ_TYPE_TAG:
 930                 /* Plain types are the final delta base. Recursion ends. */
 931                 err = add_delta(deltas, delta_offset, tslen, delta_type,
 932                     delta_size, 0);
 933                 break;
 934         case GOT_OBJ_TYPE_OFFSET_DELTA:
 935                 err = resolve_offset_delta(deltas, packidx, pack,
 936                     delta_offset, tslen, delta_type, delta_size, recursion - 1);
 937                 break;
 938         case GOT_OBJ_TYPE_REF_DELTA:
 939                 err = resolve_ref_delta(deltas, packidx, pack,
 940                     delta_offset, tslen, delta_type, delta_size, recursion - 1);
 941                 break;
 942         default:
 943                 return got_error(GOT_ERR_OBJ_TYPE);
 944         }
 945
 946         return err;
 947 }
 948
 949 static const struct got_error *
 950 open_delta_object(struct got_object **obj, struct got_packidx *packidx,
 951     struct got_pack *pack, struct got_object_id *id, off_t offset,
 952     size_t tslen, int delta_type, size_t delta_size, int idx)
 953 {
 954         const struct got_error *err = NULL;
 955         int resolved_type;
 956
 957         *obj = calloc(1, sizeof(**obj));
 958         if (*obj == NULL)
 959                 return got_error_from_errno("calloc");
 960
 961         (*obj)->flags = 0;
 962         (*obj)->hdrlen = 0;
 963         (*obj)->size = 0; /* Not known because deltas aren't applied yet. */
 964         memcpy(&(*obj)->id, id, sizeof((*obj)->id));
 965         (*obj)->pack_offset = offset + tslen;
 966
 967         STAILQ_INIT(&(*obj)->deltas.entries);
 968         (*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
 969         (*obj)->flags |= GOT_OBJ_FLAG_PACKED;
 970         (*obj)->pack_idx = idx;
 971
 972         err = got_pack_resolve_delta_chain(&(*obj)->deltas, packidx, pack,
 973             offset, tslen, delta_type, delta_size,
 974             GOT_DELTA_CHAIN_RECURSION_MAX);
 975         if (err)
 976                 goto done;
 977
 978         err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
 979         if (err)
 980                 goto done;
 981         (*obj)->type = resolved_type;
 982 done:
 983         if (err) {
 984                 got_object_close(*obj);
 985                 *obj = NULL;
 986         }
 987         return err;
 988 }
 989
 990 const struct got_error *
 991 got_packfile_open_object(struct got_object **obj, struct got_pack *pack,
 992     struct got_packidx *packidx, int idx, struct got_object_id *id)
 993 {
 994         const struct got_error *err = NULL;
 995         off_t offset;
 996         uint8_t type;
 997         uint64_t size;
 998         size_t tslen;
 999
1000         *obj = NULL;
1001
1002         offset = got_packidx_get_object_offset(packidx, idx);
1003         if (offset == (uint64_t)-1)
1004                 return got_error(GOT_ERR_BAD_PACKIDX);
1005
1006         err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
1007             pack, offset);
1008         if (err)
1009                 return err;
1010
1011         switch (type) {
1012         case GOT_OBJ_TYPE_COMMIT:
1013         case GOT_OBJ_TYPE_TREE:
1014         case GOT_OBJ_TYPE_BLOB:
1015         case GOT_OBJ_TYPE_TAG:
1016                 err = open_plain_object(obj, id, type, offset + tslen,
1017                     size, idx);
1018                 break;
1019         case GOT_OBJ_TYPE_OFFSET_DELTA:
1020         case GOT_OBJ_TYPE_REF_DELTA:
1021                 err = open_delta_object(obj, packidx, pack, id, offset,
1022                     tslen, type, size, idx);
1023                 break;
1024         default:
1025                 err = got_error(GOT_ERR_OBJ_TYPE);
1026                 break;
1027         }
1028
1029         return err;
1030 }
1031
1032 const struct got_error *
1033 got_pack_get_delta_chain_max_size(uint64_t *max_size,
1034     struct got_delta_chain *deltas, struct got_pack *pack)
1035 {
1036         struct got_delta *delta;
1037         uint64_t base_size = 0, result_size = 0;
1038
1039         *max_size = 0;
1040         STAILQ_FOREACH(delta, &deltas->entries, entry) {
1041                 /* Plain object types are the delta base. */
1042                 if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1043                     delta->type != GOT_OBJ_TYPE_TREE &&
1044                     delta->type != GOT_OBJ_TYPE_BLOB &&
1045                     delta->type != GOT_OBJ_TYPE_TAG) {
1046                         const struct got_error *err;
1047                         uint8_t *delta_buf;
1048                         size_t delta_len;
1049                         int cached = 1;
1050
1051                         got_delta_cache_get(&delta_buf, &delta_len,
1052                             pack->delta_cache, delta->data_offset);
1053                         if (delta_buf == NULL) {
1054                                 cached = 0;
1055                                 err = read_delta_data(&delta_buf, &delta_len,
1056                                     delta->data_offset, pack);
1057                                 if (err)
1058                                         return err;
1059                                 err = got_delta_cache_add(pack->delta_cache,
1060                                     delta->data_offset, delta_buf, delta_len);
1061                                 if (err == NULL)
1062                                         cached = 1;
1063                                 else if (err->code != GOT_ERR_NO_SPACE) {
1064                                         free(delta_buf);
1065                                         return err;
1066                                 }
1067                         }
1068                         err = got_delta_get_sizes(&base_size, &result_size,
1069                             delta_buf, delta_len);
1070                         if (!cached)
1071                                 free(delta_buf);
1072                         if (err)
1073                                 return err;
1074                 } else
1075                         base_size = delta->size;
1076                 if (base_size > *max_size)
1077                         *max_size = base_size;
1078                 if (result_size > *max_size)
1079                         *max_size = result_size;
1080         }
1081
1082         return NULL;
1083 }
1084
1085 const struct got_error *
1086 got_pack_get_max_delta_object_size(uint64_t *size, struct got_object *obj,
1087     struct got_pack *pack)
1088 {
1089         if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0)
1090                 return got_error(GOT_ERR_OBJ_TYPE);
1091
1092         return got_pack_get_delta_chain_max_size(size, &obj->deltas, pack);
1093 }
1094
1095 const struct got_error *
1096 got_pack_dump_delta_chain_to_file(size_t *result_size,
1097     struct got_delta_chain *deltas, struct got_pack *pack, FILE *outfile,
1098     FILE *base_file, FILE *accum_file)
1099 {
1100         const struct got_error *err = NULL;
1101         struct got_delta *delta;
1102         uint8_t *base_buf = NULL, *accum_buf = NULL, *delta_buf;
1103         size_t base_bufsz = 0, accum_size = 0, delta_len;
1104         uint64_t max_size;
1105         int n = 0;
1106
1107         *result_size = 0;
1108
1109         if (STAILQ_EMPTY(&deltas->entries))
1110                 return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1111
1112         /* We process small enough files entirely in memory for speed. */
1113         err = got_pack_get_delta_chain_max_size(&max_size, deltas, pack);
1114         if (err)
1115                 return err;
1116         if (max_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
1117                 accum_buf = malloc(max_size);
1118                 if (accum_buf == NULL)
1119                         return got_error_from_errno("malloc");
1120                 base_file = NULL;
1121                 accum_file = NULL;
1122         } else {
1123                 if (fseeko(base_file, 0L, SEEK_SET) == -1)
1124                         return got_error_from_errno("fseeko");
1125                 if (fseeko(accum_file, 0L, SEEK_SET) == -1)
1126                         return got_error_from_errno("fseeko");
1127         }
1128
1129         /* Deltas are ordered in ascending order. */
1130         STAILQ_FOREACH(delta, &deltas->entries, entry) {
1131                 int cached = 1;
1132                 if (n == 0) {
1133                         size_t mapoff;
1134                         off_t delta_data_offset;
1135
1136                         /* Plain object types are the delta base. */
1137                         if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1138                             delta->type != GOT_OBJ_TYPE_TREE &&
1139                             delta->type != GOT_OBJ_TYPE_BLOB &&
1140                             delta->type != GOT_OBJ_TYPE_TAG) {
1141                                 err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1142                                 goto done;
1143                         }
1144
1145                         delta_data_offset = delta->offset + delta->tslen;
1146                         if (delta_data_offset >= pack->filesize) {
1147                                 err = got_error(GOT_ERR_PACK_OFFSET);
1148                                 goto done;
1149                         }
1150                         if (pack->map == NULL) {
1151                                 if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1152                                     == -1) {
1153                                         err = got_error_from_errno("lseek");
1154                                         goto done;
1155                                 }
1156                         }
1157                         if (base_file) {
1158                                 if (pack->map) {
1159                                         mapoff = (size_t)delta_data_offset;
1160                                         err = got_inflate_to_file_mmap(
1161                                             &base_bufsz, NULL, NULL, pack->map,
1162                                             mapoff, pack->filesize - mapoff,
1163                                             base_file);
1164                                 } else
1165                                         err = got_inflate_to_file_fd(
1166                                             &base_bufsz, NULL, NULL, pack->fd,
1167                                             base_file);
1168                         } else {
1169                                 if (pack->map) {
1170                                         mapoff = (size_t)delta_data_offset;
1171                                         err = got_inflate_to_mem_mmap(&base_buf,
1172                                             &base_bufsz, NULL, NULL,
1173                                             pack->map, mapoff,
1174                                             pack->filesize - mapoff);
1175                                 } else
1176                                         err = got_inflate_to_mem_fd(&base_buf,
1177                                             &base_bufsz, NULL, NULL, max_size,
1178                                             pack->fd);
1179                         }
1180                         if (err)
1181                                 goto done;
1182                         n++;
1183                         if (base_file)
1184                                 rewind(base_file);
1185                         continue;
1186                 }
1187
1188                 got_delta_cache_get(&delta_buf, &delta_len,
1189                     pack->delta_cache, delta->data_offset);
1190                 if (delta_buf == NULL) {
1191                         cached = 0;
1192                         err = read_delta_data(&delta_buf, &delta_len,
1193                             delta->data_offset, pack);
1194                         if (err)
1195                                 goto done;
1196                         err = got_delta_cache_add(pack->delta_cache,
1197                             delta->data_offset, delta_buf, delta_len);
1198                         if (err == NULL)
1199                                 cached = 1;
1200                         else if (err->code != GOT_ERR_NO_SPACE) {
1201                                 free(delta_buf);
1202                                 goto done;
1203                         }
1204                 }
1205                 if (base_buf) {
1206                         err = got_delta_apply_in_mem(base_buf, base_bufsz,
1207                             delta_buf, delta_len, accum_buf,
1208                             &accum_size, max_size);
1209                         n++;
1210                 } else {
1211                         err = got_delta_apply(base_file, delta_buf,
1212                             delta_len,
1213                             /* Final delta application writes to output file. */
1214                             ++n < deltas->nentries ? accum_file : outfile,
1215                             &accum_size);
1216                 }
1217                 if (!cached)
1218                         free(delta_buf);
1219                 if (err)
1220                         goto done;
1221
1222                 if (n < deltas->nentries) {
1223                         /* Accumulated delta becomes the new base. */
1224                         if (base_buf) {
1225                                 uint8_t *tmp = accum_buf;
1226                                 /*
1227                                  * Base buffer switches roles with accumulation
1228                                  * buffer. Ensure it can hold the largest
1229                                  * result in the delta chain. The initial
1230                                  * allocation might have been smaller.
1231                                  */
1232                                 if (base_bufsz < max_size) {
1233                                         uint8_t *p;
1234                                         p = reallocarray(base_buf, 1, max_size);
1235                                         if (p == NULL) {
1236                                                 err = got_error_from_errno(
1237                                                     "reallocarray");
1238                                                 goto done;
1239                                         }
1240                                         base_buf = p;
1241                                         base_bufsz = max_size;
1242                                 }
1243                                 accum_buf = base_buf;
1244                                 base_buf = tmp;
1245                         } else {
1246                                 FILE *tmp = accum_file;
1247                                 accum_file = base_file;
1248                                 base_file = tmp;
1249                                 rewind(base_file);
1250                                 rewind(accum_file);
1251                         }
1252                 }
1253         }
1254
1255 done:
1256         free(base_buf);
1257         if (accum_buf) {
1258                 size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1259                 free(accum_buf);
1260                 if (len != accum_size)
1261                         err = got_ferror(outfile, GOT_ERR_IO);
1262         }
1263         rewind(outfile);
1264         if (err == NULL)
1265                 *result_size = accum_size;
1266         return err;
1267 }
1268
1269 const struct got_error *
1270 got_pack_dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1271     struct got_delta_chain *deltas, struct got_pack *pack)
1272 {
1273         const struct got_error *err = NULL;
1274         struct got_delta *delta;
1275         uint8_t *base_buf = NULL, *accum_buf = NULL, *delta_buf;
1276         size_t base_bufsz = 0, accum_size = 0, delta_len;
1277         uint64_t max_size;
1278         int n = 0;
1279
1280         *outbuf = NULL;
1281         *outlen = 0;
1282
1283         if (STAILQ_EMPTY(&deltas->entries))
1284                 return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1285
1286         err = got_pack_get_delta_chain_max_size(&max_size, deltas, pack);
1287         if (err)
1288                 return err;
1289         accum_buf = malloc(max_size);
1290         if (accum_buf == NULL)
1291                 return got_error_from_errno("malloc");
1292
1293         /* Deltas are ordered in ascending order. */
1294         STAILQ_FOREACH(delta, &deltas->entries, entry) {
1295                 int cached = 1;
1296                 if (n == 0) {
1297                         size_t delta_data_offset;
1298
1299                         /* Plain object types are the delta base. */
1300                         if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1301                             delta->type != GOT_OBJ_TYPE_TREE &&
1302                             delta->type != GOT_OBJ_TYPE_BLOB &&
1303                             delta->type != GOT_OBJ_TYPE_TAG) {
1304                                 err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1305                                 goto done;
1306                         }
1307
1308                         delta_data_offset = delta->offset + delta->tslen;
1309                         if (delta_data_offset >= pack->filesize) {
1310                                 err = got_error(GOT_ERR_PACK_OFFSET);
1311                                 goto done;
1312                         }
1313                         if (pack->map) {
1314                                 size_t mapoff = (size_t)delta_data_offset;
1315                                 err = got_inflate_to_mem_mmap(&base_buf,
1316                                     &base_bufsz, NULL, NULL, pack->map,
1317                                     mapoff, pack->filesize - mapoff);
1318                         } else {
1319                                 if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1320                                     == -1) {
1321                                         err = got_error_from_errno("lseek");
1322                                         goto done;
1323                                 }
1324                                 err = got_inflate_to_mem_fd(&base_buf,
1325                                     &base_bufsz, NULL, NULL, max_size,
1326                                     pack->fd);
1327                         }
1328                         if (err)
1329                                 goto done;
1330                         n++;
1331                         continue;
1332                 }
1333
1334                 got_delta_cache_get(&delta_buf, &delta_len,
1335                     pack->delta_cache, delta->data_offset);
1336                 if (delta_buf == NULL) {
1337                         cached = 0;
1338                         err = read_delta_data(&delta_buf, &delta_len,
1339                             delta->data_offset, pack);
1340                         if (err)
1341                                 goto done;
1342                         err = got_delta_cache_add(pack->delta_cache,
1343                             delta->data_offset, delta_buf, delta_len);
1344                         if (err == NULL)
1345                                 cached = 1;
1346                         else if (err->code != GOT_ERR_NO_SPACE) {
1347                                 free(delta_buf);
1348                                 goto done;
1349                         }
1350                 }
1351                 err = got_delta_apply_in_mem(base_buf, base_bufsz,
1352                     delta_buf, delta_len, accum_buf,
1353                     &accum_size, max_size);
1354                 if (!cached)
1355                         free(delta_buf);
1356                 n++;
1357                 if (err)
1358                         goto done;
1359
1360                 if (n < deltas->nentries) {
1361                         /* Accumulated delta becomes the new base. */
1362                         uint8_t *tmp = accum_buf;
1363                         /*
1364                          * Base buffer switches roles with accumulation buffer.
1365                          * Ensure it can hold the largest result in the delta
1366                          * chain. Initial allocation might have been smaller.
1367                          */
1368                         if (base_bufsz < max_size) {
1369                                 uint8_t *p;
1370                                 p = reallocarray(base_buf, 1, max_size);
1371                                 if (p == NULL) {
1372                                         err = got_error_from_errno(
1373                                             "reallocarray");
1374                                         goto done;
1375                                 }
1376                                 base_buf = p;
1377                                 base_bufsz = max_size;
1378                         }
1379                         accum_buf = base_buf;
1380                         base_buf = tmp;
1381                 }
1382         }
1383
1384 done:
1385         free(base_buf);
1386         if (err) {
1387                 free(accum_buf);
1388                 *outbuf = NULL;
1389                 *outlen = 0;
1390         } else {
1391                 *outbuf = accum_buf;
1392                 *outlen = accum_size;
1393         }
1394         return err;
1395 }
1396
1397 const struct got_error *
1398 got_packfile_extract_object(struct got_pack *pack, struct got_object *obj,
1399     FILE *outfile, FILE *base_file, FILE *accum_file)
1400 {
1401         const struct got_error *err = NULL;
1402
1403         if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1404                 return got_error(GOT_ERR_OBJ_NOT_PACKED);
1405
1406         if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1407                 if (obj->pack_offset >= pack->filesize)
1408                         return got_error(GOT_ERR_PACK_OFFSET);
1409
1410                 if (pack->map) {
1411                         size_t mapoff = (size_t)obj->pack_offset;
1412                         err = got_inflate_to_file_mmap(&obj->size, NULL, NULL,
1413                             pack->map, mapoff, pack->filesize - mapoff,
1414                             outfile);
1415                 } else {
1416                         if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1417                                 return got_error_from_errno("lseek");
1418                         err = got_inflate_to_file_fd(&obj->size, NULL, NULL,
1419                             pack->fd, outfile);
1420                 }
1421         } else
1422                 err = got_pack_dump_delta_chain_to_file(&obj->size,
1423                     &obj->deltas, pack, outfile, base_file, accum_file);
1424
1425         return err;
1426 }
1427
1428 const struct got_error *
1429 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1430     struct got_object *obj, struct got_pack *pack)
1431 {
1432         const struct got_error *err = NULL;
1433
1434         if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1435                 return got_error(GOT_ERR_OBJ_NOT_PACKED);
1436
1437         if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1438                 if (obj->pack_offset >= pack->filesize)
1439                         return got_error(GOT_ERR_PACK_OFFSET);
1440                 if (pack->map) {
1441                         size_t mapoff = (size_t)obj->pack_offset;
1442                         err = got_inflate_to_mem_mmap(buf, len, NULL, NULL,
1443                             pack->map, mapoff, pack->filesize - mapoff);
1444                 } else {
1445                         if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1446                                 return got_error_from_errno("lseek");
1447                         err = got_inflate_to_mem_fd(buf, len, NULL, NULL,
1448                             obj->size, pack->fd);
1449                 }
1450         } else
1451                 err = got_pack_dump_delta_chain_to_mem(buf, len, &obj->deltas,
1452                     pack);
1453
1454         return err;
1455 }