contrib/libarchive/libarchive/archive_read.c

   1 /*-
   2  * Copyright (c) 2003-2011 Tim Kientzle
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  17  * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
  18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 /*
  27  * This file contains the "essential" portions of the read API, that
  28  * is, stuff that will probably always be used by any client that
  29  * actually needs to read an archive.  Optional pieces have been, as
  30  * far as possible, separated out into separate files to avoid
  31  * needlessly bloating statically-linked clients.
  32  */
  33
  34 #include "archive_platform.h"
  35 __FBSDID("$FreeBSD: head/lib/libarchive/archive_read.c 201157 2009-12-29 05:30:23Z kientzle $");
  36
  37 #ifdef HAVE_ERRNO_H
  38 #include <errno.h>
  39 #endif
  40 #include <stdio.h>
  41 #ifdef HAVE_STDLIB_H
  42 #include <stdlib.h>
  43 #endif
  44 #ifdef HAVE_STRING_H
  45 #include <string.h>
  46 #endif
  47 #ifdef HAVE_UNISTD_H
  48 #include <unistd.h>
  49 #endif
  50
  51 #include "archive.h"
  52 #include "archive_entry.h"
  53 #include "archive_private.h"
  54 #include "archive_read_private.h"
  55
  56 #define minimum(a, b) (a < b ? a : b)
  57
  58 static int      choose_filters(struct archive_read *);
  59 static int      choose_format(struct archive_read *);
  60 static struct archive_vtable *archive_read_vtable(void);
  61 static int64_t  _archive_filter_bytes(struct archive *, int);
  62 static int      _archive_filter_code(struct archive *, int);
  63 static const char *_archive_filter_name(struct archive *, int);
  64 static int  _archive_filter_count(struct archive *);
  65 static int      _archive_read_close(struct archive *);
  66 static int      _archive_read_data_block(struct archive *,
  67                     const void **, size_t *, int64_t *);
  68 static int      _archive_read_free(struct archive *);
  69 static int      _archive_read_next_header(struct archive *,
  70                     struct archive_entry **);
  71 static int      _archive_read_next_header2(struct archive *,
  72                     struct archive_entry *);
  73 static int64_t  advance_file_pointer(struct archive_read_filter *, int64_t);
  74
  75 static struct archive_vtable *
  76 archive_read_vtable(void)
  77 {
  78         static struct archive_vtable av;
  79         static int inited = 0;
  80
  81         if (!inited) {
  82                 av.archive_filter_bytes = _archive_filter_bytes;
  83                 av.archive_filter_code = _archive_filter_code;
  84                 av.archive_filter_name = _archive_filter_name;
  85                 av.archive_filter_count = _archive_filter_count;
  86                 av.archive_read_data_block = _archive_read_data_block;
  87                 av.archive_read_next_header = _archive_read_next_header;
  88                 av.archive_read_next_header2 = _archive_read_next_header2;
  89                 av.archive_free = _archive_read_free;
  90                 av.archive_close = _archive_read_close;
  91                 inited = 1;
  92         }
  93         return (&av);
  94 }
  95
  96 /*
  97  * Allocate, initialize and return a struct archive object.
  98  */
  99 struct archive *
 100 archive_read_new(void)
 101 {
 102         struct archive_read *a;
 103
 104         a = (struct archive_read *)malloc(sizeof(*a));
 105         if (a == NULL)
 106                 return (NULL);
 107         memset(a, 0, sizeof(*a));
 108         a->archive.magic = ARCHIVE_READ_MAGIC;
 109
 110         a->archive.state = ARCHIVE_STATE_NEW;
 111         a->entry = archive_entry_new2(&a->archive);
 112         a->archive.vtable = archive_read_vtable();
 113
 114         return (&a->archive);
 115 }
 116
 117 /*
 118  * Record the do-not-extract-to file. This belongs in archive_read_extract.c.
 119  */
 120 void
 121 archive_read_extract_set_skip_file(struct archive *_a, int64_t d, int64_t i)
 122 {
 123         struct archive_read *a = (struct archive_read *)_a;
 124
 125         if (ARCHIVE_OK != __archive_check_magic(_a, ARCHIVE_READ_MAGIC,
 126                 ARCHIVE_STATE_ANY, "archive_read_extract_set_skip_file"))
 127                 return;
 128         a->skip_file_set = 1;
 129         a->skip_file_dev = d;
 130         a->skip_file_ino = i;
 131 }
 132
 133 /*
 134  * Open the archive
 135  */
 136 int
 137 archive_read_open(struct archive *a, void *client_data,
 138     archive_open_callback *client_opener, archive_read_callback *client_reader,
 139     archive_close_callback *client_closer)
 140 {
 141         /* Old archive_read_open() is just a thin shell around
 142          * archive_read_open1. */
 143         archive_read_set_open_callback(a, client_opener);
 144         archive_read_set_read_callback(a, client_reader);
 145         archive_read_set_close_callback(a, client_closer);
 146         archive_read_set_callback_data(a, client_data);
 147         return archive_read_open1(a);
 148 }
 149
 150
 151 int
 152 archive_read_open2(struct archive *a, void *client_data,
 153     archive_open_callback *client_opener,
 154     archive_read_callback *client_reader,
 155     archive_skip_callback *client_skipper,
 156     archive_close_callback *client_closer)
 157 {
 158         /* Old archive_read_open2() is just a thin shell around
 159          * archive_read_open1. */
 160         archive_read_set_callback_data(a, client_data);
 161         archive_read_set_open_callback(a, client_opener);
 162         archive_read_set_read_callback(a, client_reader);
 163         archive_read_set_skip_callback(a, client_skipper);
 164         archive_read_set_close_callback(a, client_closer);
 165         return archive_read_open1(a);
 166 }
 167
 168 static ssize_t
 169 client_read_proxy(struct archive_read_filter *self, const void **buff)
 170 {
 171         ssize_t r;
 172         r = (self->archive->client.reader)(&self->archive->archive,
 173             self->data, buff);
 174         return (r);
 175 }
 176
 177 static int64_t
 178 client_skip_proxy(struct archive_read_filter *self, int64_t request)
 179 {
 180         if (request < 0)
 181                 __archive_errx(1, "Negative skip requested.");
 182         if (request == 0)
 183                 return 0;
 184
 185         if (self->archive->client.skipper != NULL) {
 186                 /* Seek requests over 1GiB are broken down into
 187                  * multiple seeks.  This avoids overflows when the
 188                  * requests get passed through 32-bit arguments. */
 189                 int64_t skip_limit = (int64_t)1 << 30;
 190                 int64_t total = 0;
 191                 for (;;) {
 192                         int64_t get, ask = request;
 193                         if (ask > skip_limit)
 194                                 ask = skip_limit;
 195                         get = (self->archive->client.skipper)
 196                                 (&self->archive->archive, self->data, ask);
 197                         if (get == 0)
 198                                 return (total);
 199                         request -= get;
 200                         total += get;
 201                 }
 202         } else if (self->archive->client.seeker != NULL
 203                 && request > 64 * 1024) {
 204                 /* If the client provided a seeker but not a skipper,
 205                  * we can use the seeker to skip forward.
 206                  *
 207                  * Note: This isn't always a good idea.  The client
 208                  * skipper is allowed to skip by less than requested
 209                  * if it needs to maintain block alignment.  The
 210                  * seeker is not allowed to play such games, so using
 211                  * the seeker here may be a performance loss compared
 212                  * to just reading and discarding.  That's why we
 213                  * only do this for skips of over 64k.
 214                  */
 215                 int64_t before = self->position;
 216                 int64_t after = (self->archive->client.seeker)
 217                     (&self->archive->archive, self->data, request, SEEK_CUR);
 218                 if (after != before + request)
 219                         return ARCHIVE_FATAL;
 220                 return after - before;
 221         }
 222         return 0;
 223 }
 224
 225 static int64_t
 226 client_seek_proxy(struct archive_read_filter *self, int64_t offset, int whence)
 227 {
 228         /* DO NOT use the skipper here!  If we transparently handled
 229          * forward seek here by using the skipper, that will break
 230          * other libarchive code that assumes a successful forward
 231          * seek means it can also seek backwards.
 232          */
 233         if (self->archive->client.seeker == NULL)
 234                 return (ARCHIVE_FAILED);
 235         return (self->archive->client.seeker)(&self->archive->archive,
 236             self->data, offset, whence);
 237 }
 238
 239 static int
 240 client_close_proxy(struct archive_read_filter *self)
 241 {
 242         int r = ARCHIVE_OK, r2;
 243         unsigned int i;
 244
 245         if (self->archive->client.closer == NULL)
 246                 return (r);
 247         for (i = 0; i < self->archive->client.nodes; i++)
 248         {
 249                 r2 = (self->archive->client.closer)
 250                         ((struct archive *)self->archive,
 251                                 self->archive->client.dataset[i].data);
 252                 if (r > r2)
 253                         r = r2;
 254         }
 255         return (r);
 256 }
 257
 258 static int
 259 client_open_proxy(struct archive_read_filter *self)
 260 {
 261   int r = ARCHIVE_OK;
 262         if (self->archive->client.opener != NULL)
 263                 r = (self->archive->client.opener)(
 264                     (struct archive *)self->archive, self->data);
 265         return (r);
 266 }
 267
 268 static int
 269 client_switch_proxy(struct archive_read_filter *self, unsigned int iindex)
 270 {
 271   int r1 = ARCHIVE_OK, r2 = ARCHIVE_OK;
 272         void *data2 = NULL;
 273
 274         /* Don't do anything if already in the specified data node */
 275         if (self->archive->client.cursor == iindex)
 276                 return (ARCHIVE_OK);
 277
 278         self->archive->client.cursor = iindex;
 279         data2 = self->archive->client.dataset[self->archive->client.cursor].data;
 280         if (self->archive->client.switcher != NULL)
 281         {
 282                 r1 = r2 = (self->archive->client.switcher)
 283                         ((struct archive *)self->archive, self->data, data2);
 284                 self->data = data2;
 285         }
 286         else
 287         {
 288                 /* Attempt to call close and open instead */
 289                 if (self->archive->client.closer != NULL)
 290                         r1 = (self->archive->client.closer)
 291                                 ((struct archive *)self->archive, self->data);
 292                 self->data = data2;
 293                 if (self->archive->client.opener != NULL)
 294                         r2 = (self->archive->client.opener)
 295                                 ((struct archive *)self->archive, self->data);
 296         }
 297         return (r1 < r2) ? r1 : r2;
 298 }
 299
 300 int
 301 archive_read_set_open_callback(struct archive *_a,
 302     archive_open_callback *client_opener)
 303 {
 304         struct archive_read *a = (struct archive_read *)_a;
 305         archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
 306             "archive_read_set_open_callback");
 307         a->client.opener = client_opener;
 308         return ARCHIVE_OK;
 309 }
 310
 311 int
 312 archive_read_set_read_callback(struct archive *_a,
 313     archive_read_callback *client_reader)
 314 {
 315         struct archive_read *a = (struct archive_read *)_a;
 316         archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
 317             "archive_read_set_read_callback");
 318         a->client.reader = client_reader;
 319         return ARCHIVE_OK;
 320 }
 321
 322 int
 323 archive_read_set_skip_callback(struct archive *_a,
 324     archive_skip_callback *client_skipper)
 325 {
 326         struct archive_read *a = (struct archive_read *)_a;
 327         archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
 328             "archive_read_set_skip_callback");
 329         a->client.skipper = client_skipper;
 330         return ARCHIVE_OK;
 331 }
 332
 333 int
 334 archive_read_set_seek_callback(struct archive *_a,
 335     archive_seek_callback *client_seeker)
 336 {
 337         struct archive_read *a = (struct archive_read *)_a;
 338         archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
 339             "archive_read_set_seek_callback");
 340         a->client.seeker = client_seeker;
 341         return ARCHIVE_OK;
 342 }
 343
 344 int
 345 archive_read_set_close_callback(struct archive *_a,
 346     archive_close_callback *client_closer)
 347 {
 348         struct archive_read *a = (struct archive_read *)_a;
 349         archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
 350             "archive_read_set_close_callback");
 351         a->client.closer = client_closer;
 352         return ARCHIVE_OK;
 353 }
 354
 355 int
 356 archive_read_set_switch_callback(struct archive *_a,
 357     archive_switch_callback *client_switcher)
 358 {
 359         struct archive_read *a = (struct archive_read *)_a;
 360         archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
 361             "archive_read_set_switch_callback");
 362         a->client.switcher = client_switcher;
 363         return ARCHIVE_OK;
 364 }
 365
 366 int
 367 archive_read_set_callback_data(struct archive *_a, void *client_data)
 368 {
 369         return archive_read_set_callback_data2(_a, client_data, 0);
 370 }
 371
 372 int
 373 archive_read_set_callback_data2(struct archive *_a, void *client_data,
 374     unsigned int iindex)
 375 {
 376         struct archive_read *a = (struct archive_read *)_a;
 377         archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
 378             "archive_read_set_callback_data2");
 379
 380         if (a->client.nodes == 0)
 381         {
 382                 a->client.dataset = (struct archive_read_data_node *)
 383                     calloc(1, sizeof(*a->client.dataset));
 384                 if (a->client.dataset == NULL)
 385                 {
 386                         archive_set_error(&a->archive, ENOMEM,
 387                                 "No memory.");
 388                         return ARCHIVE_FATAL;
 389                 }
 390                 a->client.nodes = 1;
 391         }
 392
 393         if (iindex > a->client.nodes - 1)
 394         {
 395                 archive_set_error(&a->archive, EINVAL,
 396                         "Invalid index specified.");
 397                 return ARCHIVE_FATAL;
 398         }
 399         a->client.dataset[iindex].data = client_data;
 400         a->client.dataset[iindex].begin_position = -1;
 401         a->client.dataset[iindex].total_size = -1;
 402         return ARCHIVE_OK;
 403 }
 404
 405 int
 406 archive_read_add_callback_data(struct archive *_a, void *client_data,
 407     unsigned int iindex)
 408 {
 409         struct archive_read *a = (struct archive_read *)_a;
 410         void *p;
 411         unsigned int i;
 412
 413         archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
 414             "archive_read_add_callback_data");
 415         if (iindex > a->client.nodes) {
 416                 archive_set_error(&a->archive, EINVAL,
 417                         "Invalid index specified.");
 418                 return ARCHIVE_FATAL;
 419         }
 420         p = realloc(a->client.dataset, sizeof(*a->client.dataset)
 421                 * (++(a->client.nodes)));
 422         if (p == NULL) {
 423                 archive_set_error(&a->archive, ENOMEM,
 424                         "No memory.");
 425                 return ARCHIVE_FATAL;
 426         }
 427         a->client.dataset = (struct archive_read_data_node *)p;
 428         for (i = a->client.nodes - 1; i > iindex && i > 0; i--) {
 429                 a->client.dataset[i].data = a->client.dataset[i-1].data;
 430                 a->client.dataset[i].begin_position = -1;
 431                 a->client.dataset[i].total_size = -1;
 432         }
 433         a->client.dataset[iindex].data = client_data;
 434         a->client.dataset[iindex].begin_position = -1;
 435         a->client.dataset[iindex].total_size = -1;
 436         return ARCHIVE_OK;
 437 }
 438
 439 int
 440 archive_read_append_callback_data(struct archive *_a, void *client_data)
 441 {
 442         struct archive_read *a = (struct archive_read *)_a;
 443         return archive_read_add_callback_data(_a, client_data, a->client.nodes);
 444 }
 445
 446 int
 447 archive_read_prepend_callback_data(struct archive *_a, void *client_data)
 448 {
 449         return archive_read_add_callback_data(_a, client_data, 0);
 450 }
 451
 452 int
 453 archive_read_open1(struct archive *_a)
 454 {
 455         struct archive_read *a = (struct archive_read *)_a;
 456         struct archive_read_filter *filter, *tmp;
 457         int slot, e;
 458         unsigned int i;
 459
 460         archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
 461             "archive_read_open");
 462         archive_clear_error(&a->archive);
 463
 464         if (a->client.reader == NULL) {
 465                 archive_set_error(&a->archive, EINVAL,
 466                     "No reader function provided to archive_read_open");
 467                 a->archive.state = ARCHIVE_STATE_FATAL;
 468                 return (ARCHIVE_FATAL);
 469         }
 470
 471         /* Open data source. */
 472         if (a->client.opener != NULL) {
 473                 e = (a->client.opener)(&a->archive, a->client.dataset[0].data);
 474                 if (e != 0) {
 475                         /* If the open failed, call the closer to clean up. */
 476                         if (a->client.closer) {
 477                                 for (i = 0; i < a->client.nodes; i++)
 478                                         (a->client.closer)(&a->archive,
 479                                             a->client.dataset[i].data);
 480                         }
 481                         return (e);
 482                 }
 483         }
 484
 485         filter = calloc(1, sizeof(*filter));
 486         if (filter == NULL)
 487                 return (ARCHIVE_FATAL);
 488         filter->bidder = NULL;
 489         filter->upstream = NULL;
 490         filter->archive = a;
 491         filter->data = a->client.dataset[0].data;
 492         filter->open = client_open_proxy;
 493         filter->read = client_read_proxy;
 494         filter->skip = client_skip_proxy;
 495         filter->seek = client_seek_proxy;
 496         filter->close = client_close_proxy;
 497         filter->sswitch = client_switch_proxy;
 498         filter->name = "none";
 499         filter->code = ARCHIVE_FILTER_NONE;
 500
 501         a->client.dataset[0].begin_position = 0;
 502         if (!a->filter || !a->bypass_filter_bidding)
 503         {
 504                 a->filter = filter;
 505                 /* Build out the input pipeline. */
 506                 e = choose_filters(a);
 507                 if (e < ARCHIVE_WARN) {
 508                         a->archive.state = ARCHIVE_STATE_FATAL;
 509                         return (ARCHIVE_FATAL);
 510                 }
 511         }
 512         else
 513         {
 514                 /* Need to add "NONE" type filter at the end of the filter chain */
 515                 tmp = a->filter;
 516                 while (tmp->upstream)
 517                         tmp = tmp->upstream;
 518                 tmp->upstream = filter;
 519         }
 520
 521         if (!a->format)
 522         {
 523                 slot = choose_format(a);
 524                 if (slot < 0) {
 525                         __archive_read_close_filters(a);
 526                         a->archive.state = ARCHIVE_STATE_FATAL;
 527                         return (ARCHIVE_FATAL);
 528                 }
 529                 a->format = &(a->formats[slot]);
 530         }
 531
 532         a->archive.state = ARCHIVE_STATE_HEADER;
 533
 534         /* Ensure libarchive starts from the first node in a multivolume set */
 535         client_switch_proxy(a->filter, 0);
 536         return (e);
 537 }
 538
 539 /*
 540  * Allow each registered stream transform to bid on whether
 541  * it wants to handle this stream.  Repeat until we've finished
 542  * building the pipeline.
 543  */
 544 static int
 545 choose_filters(struct archive_read *a)
 546 {
 547         int number_bidders, i, bid, best_bid;
 548         struct archive_read_filter_bidder *bidder, *best_bidder;
 549         struct archive_read_filter *filter;
 550         ssize_t avail;
 551         int r;
 552
 553         for (;;) {
 554                 number_bidders = sizeof(a->bidders) / sizeof(a->bidders[0]);
 555
 556                 best_bid = 0;
 557                 best_bidder = NULL;
 558
 559                 bidder = a->bidders;
 560                 for (i = 0; i < number_bidders; i++, bidder++) {
 561                         if (bidder->bid != NULL) {
 562                                 bid = (bidder->bid)(bidder, a->filter);
 563                                 if (bid > best_bid) {
 564                                         best_bid = bid;
 565                                         best_bidder = bidder;
 566                                 }
 567                         }
 568                 }
 569
 570                 /* If no bidder, we're done. */
 571                 if (best_bidder == NULL) {
 572                         /* Verify the filter by asking it for some data. */
 573                         __archive_read_filter_ahead(a->filter, 1, &avail);
 574                         if (avail < 0) {
 575                                 __archive_read_close_filters(a);
 576                                 __archive_read_free_filters(a);
 577                                 return (ARCHIVE_FATAL);
 578                         }
 579                         a->archive.compression_name = a->filter->name;
 580                         a->archive.compression_code = a->filter->code;
 581                         return (ARCHIVE_OK);
 582                 }
 583
 584                 filter
 585                     = (struct archive_read_filter *)calloc(1, sizeof(*filter));
 586                 if (filter == NULL)
 587                         return (ARCHIVE_FATAL);
 588                 filter->bidder = best_bidder;
 589                 filter->archive = a;
 590                 filter->upstream = a->filter;
 591                 a->filter = filter;
 592                 r = (best_bidder->init)(a->filter);
 593                 if (r != ARCHIVE_OK) {
 594                         __archive_read_close_filters(a);
 595                         __archive_read_free_filters(a);
 596                         return (ARCHIVE_FATAL);
 597                 }
 598         }
 599 }
 600
 601 /*
 602  * Read header of next entry.
 603  */
 604 static int
 605 _archive_read_next_header2(struct archive *_a, struct archive_entry *entry)
 606 {
 607         struct archive_read *a = (struct archive_read *)_a;
 608         int r1 = ARCHIVE_OK, r2;
 609
 610         archive_check_magic(_a, ARCHIVE_READ_MAGIC,
 611             ARCHIVE_STATE_HEADER | ARCHIVE_STATE_DATA,
 612             "archive_read_next_header");
 613
 614         archive_entry_clear(entry);
 615         archive_clear_error(&a->archive);
 616
 617         /*
 618          * If client didn't consume entire data, skip any remainder
 619          * (This is especially important for GNU incremental directories.)
 620          */
 621         if (a->archive.state == ARCHIVE_STATE_DATA) {
 622                 r1 = archive_read_data_skip(&a->archive);
 623                 if (r1 == ARCHIVE_EOF)
 624                         archive_set_error(&a->archive, EIO,
 625                             "Premature end-of-file.");
 626                 if (r1 == ARCHIVE_EOF || r1 == ARCHIVE_FATAL) {
 627                         a->archive.state = ARCHIVE_STATE_FATAL;
 628                         return (ARCHIVE_FATAL);
 629                 }
 630         }
 631
 632         /* Record start-of-header offset in uncompressed stream. */
 633         a->header_position = a->filter->position;
 634
 635         ++_a->file_count;
 636         r2 = (a->format->read_header)(a, entry);
 637
 638         /*
 639          * EOF and FATAL are persistent at this layer.  By
 640          * modifying the state, we guarantee that future calls to
 641          * read a header or read data will fail.
 642          */
 643         switch (r2) {
 644         case ARCHIVE_EOF:
 645                 a->archive.state = ARCHIVE_STATE_EOF;
 646                 --_a->file_count;/* Revert a file counter. */
 647                 break;
 648         case ARCHIVE_OK:
 649                 a->archive.state = ARCHIVE_STATE_DATA;
 650                 break;
 651         case ARCHIVE_WARN:
 652                 a->archive.state = ARCHIVE_STATE_DATA;
 653                 break;
 654         case ARCHIVE_RETRY:
 655                 break;
 656         case ARCHIVE_FATAL:
 657                 a->archive.state = ARCHIVE_STATE_FATAL;
 658                 break;
 659         }
 660
 661         a->read_data_output_offset = 0;
 662         a->read_data_remaining = 0;
 663         a->read_data_is_posix_read = 0;
 664         a->read_data_requested = 0;
 665         a->data_start_node = a->client.cursor;
 666         /* EOF always wins; otherwise return the worst error. */
 667         return (r2 < r1 || r2 == ARCHIVE_EOF) ? r2 : r1;
 668 }
 669
 670 int
 671 _archive_read_next_header(struct archive *_a, struct archive_entry **entryp)
 672 {
 673         int ret;
 674         struct archive_read *a = (struct archive_read *)_a;
 675         *entryp = NULL;
 676         ret = _archive_read_next_header2(_a, a->entry);
 677         *entryp = a->entry;
 678         return ret;
 679 }
 680
 681 /*
 682  * Allow each registered format to bid on whether it wants to handle
 683  * the next entry.  Return index of winning bidder.
 684  */
 685 static int
 686 choose_format(struct archive_read *a)
 687 {
 688         int slots;
 689         int i;
 690         int bid, best_bid;
 691         int best_bid_slot;
 692
 693         slots = sizeof(a->formats) / sizeof(a->formats[0]);
 694         best_bid = -1;
 695         best_bid_slot = -1;
 696
 697         /* Set up a->format for convenience of bidders. */
 698         a->format = &(a->formats[0]);
 699         for (i = 0; i < slots; i++, a->format++) {
 700                 if (a->format->bid) {
 701                         bid = (a->format->bid)(a, best_bid);
 702                         if (bid == ARCHIVE_FATAL)
 703                                 return (ARCHIVE_FATAL);
 704                         if (a->filter->position != 0)
 705                                 __archive_read_seek(a, 0, SEEK_SET);
 706                         if ((bid > best_bid) || (best_bid_slot < 0)) {
 707                                 best_bid = bid;
 708                                 best_bid_slot = i;
 709                         }
 710                 }
 711         }
 712
 713         /*
 714          * There were no bidders; this is a serious programmer error
 715          * and demands a quick and definitive abort.
 716          */
 717         if (best_bid_slot < 0) {
 718                 archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
 719                     "No formats registered");
 720                 return (ARCHIVE_FATAL);
 721         }
 722
 723         /*
 724          * There were bidders, but no non-zero bids; this means we
 725          * can't support this stream.
 726          */
 727         if (best_bid < 1) {
 728                 archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
 729                     "Unrecognized archive format");
 730                 return (ARCHIVE_FATAL);
 731         }
 732
 733         return (best_bid_slot);
 734 }
 735
 736 /*
 737  * Return the file offset (within the uncompressed data stream) where
 738  * the last header started.
 739  */
 740 int64_t
 741 archive_read_header_position(struct archive *_a)
 742 {
 743         struct archive_read *a = (struct archive_read *)_a;
 744         archive_check_magic(_a, ARCHIVE_READ_MAGIC,
 745             ARCHIVE_STATE_ANY, "archive_read_header_position");
 746         return (a->header_position);
 747 }
 748
 749 /*
 750  * Read data from an archive entry, using a read(2)-style interface.
 751  * This is a convenience routine that just calls
 752  * archive_read_data_block and copies the results into the client
 753  * buffer, filling any gaps with zero bytes.  Clients using this
 754  * API can be completely ignorant of sparse-file issues; sparse files
 755  * will simply be padded with nulls.
 756  *
 757  * DO NOT intermingle calls to this function and archive_read_data_block
 758  * to read a single entry body.
 759  */
 760 ssize_t
 761 archive_read_data(struct archive *_a, void *buff, size_t s)
 762 {
 763         struct archive_read *a = (struct archive_read *)_a;
 764         char    *dest;
 765         const void *read_buf;
 766         size_t   bytes_read;
 767         size_t   len;
 768         int      r;
 769
 770         bytes_read = 0;
 771         dest = (char *)buff;
 772
 773         while (s > 0) {
 774                 if (a->read_data_remaining == 0) {
 775                         read_buf = a->read_data_block;
 776                         a->read_data_is_posix_read = 1;
 777                         a->read_data_requested = s;
 778                         r = _archive_read_data_block(&a->archive, &read_buf,
 779                             &a->read_data_remaining, &a->read_data_offset);
 780                         a->read_data_block = read_buf;
 781                         if (r == ARCHIVE_EOF)
 782                                 return (bytes_read);
 783                         /*
 784                          * Error codes are all negative, so the status
 785                          * return here cannot be confused with a valid
 786                          * byte count.  (ARCHIVE_OK is zero.)
 787                          */
 788                         if (r < ARCHIVE_OK)
 789                                 return (r);
 790                 }
 791
 792                 if (a->read_data_offset < a->read_data_output_offset) {
 793                         archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
 794                             "Encountered out-of-order sparse blocks");
 795                         return (ARCHIVE_RETRY);
 796                 }
 797
 798                 /* Compute the amount of zero padding needed. */
 799                 if (a->read_data_output_offset + (int64_t)s <
 800                     a->read_data_offset) {
 801                         len = s;
 802                 } else if (a->read_data_output_offset <
 803                     a->read_data_offset) {
 804                         len = (size_t)(a->read_data_offset -
 805                             a->read_data_output_offset);
 806                 } else
 807                         len = 0;
 808
 809                 /* Add zeroes. */
 810                 memset(dest, 0, len);
 811                 s -= len;
 812                 a->read_data_output_offset += len;
 813                 dest += len;
 814                 bytes_read += len;
 815
 816                 /* Copy data if there is any space left. */
 817                 if (s > 0) {
 818                         len = a->read_data_remaining;
 819                         if (len > s)
 820                                 len = s;
 821                         memcpy(dest, a->read_data_block, len);
 822                         s -= len;
 823                         a->read_data_block += len;
 824                         a->read_data_remaining -= len;
 825                         a->read_data_output_offset += len;
 826                         a->read_data_offset += len;
 827                         dest += len;
 828                         bytes_read += len;
 829                 }
 830         }
 831         a->read_data_is_posix_read = 0;
 832         a->read_data_requested = 0;
 833         return (bytes_read);
 834 }
 835
 836 /*
 837  * Skip over all remaining data in this entry.
 838  */
 839 int
 840 archive_read_data_skip(struct archive *_a)
 841 {
 842         struct archive_read *a = (struct archive_read *)_a;
 843         int r;
 844         const void *buff;
 845         size_t size;
 846         int64_t offset;
 847
 848         archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_DATA,
 849             "archive_read_data_skip");
 850
 851         if (a->format->read_data_skip != NULL)
 852                 r = (a->format->read_data_skip)(a);
 853         else {
 854                 while ((r = archive_read_data_block(&a->archive,
 855                             &buff, &size, &offset))
 856                     == ARCHIVE_OK)
 857                         ;
 858         }
 859
 860         if (r == ARCHIVE_EOF)
 861                 r = ARCHIVE_OK;
 862
 863         a->archive.state = ARCHIVE_STATE_HEADER;
 864         return (r);
 865 }
 866
 867 int64_t
 868 archive_seek_data(struct archive *_a, int64_t offset, int whence)
 869 {
 870         struct archive_read *a = (struct archive_read *)_a;
 871         archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_DATA,
 872             "archive_seek_data_block");
 873
 874         if (a->format->seek_data == NULL) {
 875                 archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER,
 876                     "Internal error: "
 877                     "No format_seek_data_block function registered");
 878                 return (ARCHIVE_FATAL);
 879         }
 880
 881         return (a->format->seek_data)(a, offset, whence);
 882 }
 883
 884 /*
 885  * Read the next block of entry data from the archive.
 886  * This is a zero-copy interface; the client receives a pointer,
 887  * size, and file offset of the next available block of data.
 888  *
 889  * Returns ARCHIVE_OK if the operation is successful, ARCHIVE_EOF if
 890  * the end of entry is encountered.
 891  */
 892 static int
 893 _archive_read_data_block(struct archive *_a,
 894     const void **buff, size_t *size, int64_t *offset)
 895 {
 896         struct archive_read *a = (struct archive_read *)_a;
 897         archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_DATA,
 898             "archive_read_data_block");
 899
 900         if (a->format->read_data == NULL) {
 901                 archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER,
 902                     "Internal error: "
 903                     "No format_read_data_block function registered");
 904                 return (ARCHIVE_FATAL);
 905         }
 906
 907         return (a->format->read_data)(a, buff, size, offset);
 908 }
 909
 910 int
 911 __archive_read_close_filters(struct archive_read *a)
 912 {
 913         struct archive_read_filter *f = a->filter;
 914         int r = ARCHIVE_OK;
 915         /* Close each filter in the pipeline. */
 916         while (f != NULL) {
 917                 struct archive_read_filter *t = f->upstream;
 918                 if (!f->closed && f->close != NULL) {
 919                         int r1 = (f->close)(f);
 920                         f->closed = 1;
 921                         if (r1 < r)
 922                                 r = r1;
 923                 }
 924                 free(f->buffer);
 925                 f->buffer = NULL;
 926                 f = t;
 927         }
 928         return r;
 929 }
 930
 931 void
 932 __archive_read_free_filters(struct archive_read *a)
 933 {
 934         while (a->filter != NULL) {
 935                 struct archive_read_filter *t = a->filter->upstream;
 936                 free(a->filter);
 937                 a->filter = t;
 938         }
 939 }
 940
 941 /*
 942  * return the count of # of filters in use
 943  */
 944 static int
 945 _archive_filter_count(struct archive *_a)
 946 {
 947         struct archive_read *a = (struct archive_read *)_a;
 948         struct archive_read_filter *p = a->filter;
 949         int count = 0;
 950         while(p) {
 951                 count++;
 952                 p = p->upstream;
 953         }
 954         return count;
 955 }
 956
 957 /*
 958  * Close the file and all I/O.
 959  */
 960 static int
 961 _archive_read_close(struct archive *_a)
 962 {
 963         struct archive_read *a = (struct archive_read *)_a;
 964         int r = ARCHIVE_OK, r1 = ARCHIVE_OK;
 965
 966         archive_check_magic(&a->archive, ARCHIVE_READ_MAGIC,
 967             ARCHIVE_STATE_ANY | ARCHIVE_STATE_FATAL, "archive_read_close");
 968         if (a->archive.state == ARCHIVE_STATE_CLOSED)
 969                 return (ARCHIVE_OK);
 970         archive_clear_error(&a->archive);
 971         a->archive.state = ARCHIVE_STATE_CLOSED;
 972
 973         /* TODO: Clean up the formatters. */
 974
 975         /* Release the filter objects. */
 976         r1 = __archive_read_close_filters(a);
 977         if (r1 < r)
 978                 r = r1;
 979
 980         return (r);
 981 }
 982
 983 /*
 984  * Release memory and other resources.
 985  */
 986 static int
 987 _archive_read_free(struct archive *_a)
 988 {
 989         struct archive_read *a = (struct archive_read *)_a;
 990         int i, n;
 991         int slots;
 992         int r = ARCHIVE_OK;
 993
 994         if (_a == NULL)
 995                 return (ARCHIVE_OK);
 996         archive_check_magic(_a, ARCHIVE_READ_MAGIC,
 997             ARCHIVE_STATE_ANY | ARCHIVE_STATE_FATAL, "archive_read_free");
 998         if (a->archive.state != ARCHIVE_STATE_CLOSED
 999             && a->archive.state != ARCHIVE_STATE_FATAL)
1000                 r = archive_read_close(&a->archive);
1001
1002         /* Call cleanup functions registered by optional components. */
1003         if (a->cleanup_archive_extract != NULL)
1004                 r = (a->cleanup_archive_extract)(a);
1005
1006         /* Cleanup format-specific data. */
1007         slots = sizeof(a->formats) / sizeof(a->formats[0]);
1008         for (i = 0; i < slots; i++) {
1009                 a->format = &(a->formats[i]);
1010                 if (a->formats[i].cleanup)
1011                         (a->formats[i].cleanup)(a);
1012         }
1013
1014         /* Free the filters */
1015         __archive_read_free_filters(a);
1016
1017         /* Release the bidder objects. */
1018         n = sizeof(a->bidders)/sizeof(a->bidders[0]);
1019         for (i = 0; i < n; i++) {
1020                 if (a->bidders[i].free != NULL) {
1021                         int r1 = (a->bidders[i].free)(&a->bidders[i]);
1022                         if (r1 < r)
1023                                 r = r1;
1024                 }
1025         }
1026
1027         archive_string_free(&a->archive.error_string);
1028         if (a->entry)
1029                 archive_entry_free(a->entry);
1030         a->archive.magic = 0;
1031         __archive_clean(&a->archive);
1032         free(a->client.dataset);
1033         free(a);
1034         return (r);
1035 }
1036
1037 static struct archive_read_filter *
1038 get_filter(struct archive *_a, int n)
1039 {
1040         struct archive_read *a = (struct archive_read *)_a;
1041         struct archive_read_filter *f = a->filter;
1042         /* We use n == -1 for 'the last filter', which is always the
1043          * client proxy. */
1044         if (n == -1 && f != NULL) {
1045                 struct archive_read_filter *last = f;
1046                 f = f->upstream;
1047                 while (f != NULL) {
1048                         last = f;
1049                         f = f->upstream;
1050                 }
1051                 return (last);
1052         }
1053         if (n < 0)
1054                 return NULL;
1055         while (n > 0 && f != NULL) {
1056                 f = f->upstream;
1057                 --n;
1058         }
1059         return (f);
1060 }
1061
1062 static int
1063 _archive_filter_code(struct archive *_a, int n)
1064 {
1065         struct archive_read_filter *f = get_filter(_a, n);
1066         return f == NULL ? -1 : f->code;
1067 }
1068
1069 static const char *
1070 _archive_filter_name(struct archive *_a, int n)
1071 {
1072         struct archive_read_filter *f = get_filter(_a, n);
1073         return f == NULL ? NULL : f->name;
1074 }
1075
1076 static int64_t
1077 _archive_filter_bytes(struct archive *_a, int n)
1078 {
1079         struct archive_read_filter *f = get_filter(_a, n);
1080         return f == NULL ? -1 : f->position;
1081 }
1082
1083 /*
1084  * Used internally by read format handlers to register their bid and
1085  * initialization functions.
1086  */
1087 int
1088 __archive_read_register_format(struct archive_read *a,
1089     void *format_data,
1090     const char *name,
1091     int (*bid)(struct archive_read *, int),
1092     int (*options)(struct archive_read *, const char *, const char *),
1093     int (*read_header)(struct archive_read *, struct archive_entry *),
1094     int (*read_data)(struct archive_read *, const void **, size_t *, int64_t *),
1095     int (*read_data_skip)(struct archive_read *),
1096     int64_t (*seek_data)(struct archive_read *, int64_t, int),
1097     int (*cleanup)(struct archive_read *))
1098 {
1099         int i, number_slots;
1100
1101         archive_check_magic(&a->archive,
1102             ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
1103             "__archive_read_register_format");
1104
1105         number_slots = sizeof(a->formats) / sizeof(a->formats[0]);
1106
1107         for (i = 0; i < number_slots; i++) {
1108                 if (a->formats[i].bid == bid)
1109                         return (ARCHIVE_WARN); /* We've already installed */
1110                 if (a->formats[i].bid == NULL) {
1111                         a->formats[i].bid = bid;
1112                         a->formats[i].options = options;
1113                         a->formats[i].read_header = read_header;
1114                         a->formats[i].read_data = read_data;
1115                         a->formats[i].read_data_skip = read_data_skip;
1116                         a->formats[i].seek_data = seek_data;
1117                         a->formats[i].cleanup = cleanup;
1118                         a->formats[i].data = format_data;
1119                         a->formats[i].name = name;
1120                         return (ARCHIVE_OK);
1121                 }
1122         }
1123
1124         archive_set_error(&a->archive, ENOMEM,
1125             "Not enough slots for format registration");
1126         return (ARCHIVE_FATAL);
1127 }
1128
1129 /*
1130  * Used internally by decompression routines to register their bid and
1131  * initialization functions.
1132  */
1133 int
1134 __archive_read_get_bidder(struct archive_read *a,
1135     struct archive_read_filter_bidder **bidder)
1136 {
1137         int i, number_slots;
1138
1139         number_slots = sizeof(a->bidders) / sizeof(a->bidders[0]);
1140
1141         for (i = 0; i < number_slots; i++) {
1142                 if (a->bidders[i].bid == NULL) {
1143                         memset(a->bidders + i, 0, sizeof(a->bidders[0]));
1144                         *bidder = (a->bidders + i);
1145                         return (ARCHIVE_OK);
1146                 }
1147         }
1148
1149         archive_set_error(&a->archive, ENOMEM,
1150             "Not enough slots for filter registration");
1151         return (ARCHIVE_FATAL);
1152 }
1153
1154 /*
1155  * The next section implements the peek/consume internal I/O
1156  * system used by archive readers.  This system allows simple
1157  * read-ahead for consumers while preserving zero-copy operation
1158  * most of the time.
1159  *
1160  * The two key operations:
1161  *  * The read-ahead function returns a pointer to a block of data
1162  *    that satisfies a minimum request.
1163  *  * The consume function advances the file pointer.
1164  *
1165  * In the ideal case, filters generate blocks of data
1166  * and __archive_read_ahead() just returns pointers directly into
1167  * those blocks.  Then __archive_read_consume() just bumps those
1168  * pointers.  Only if your request would span blocks does the I/O
1169  * layer use a copy buffer to provide you with a contiguous block of
1170  * data.
1171  *
1172  * A couple of useful idioms:
1173  *  * "I just want some data."  Ask for 1 byte and pay attention to
1174  *    the "number of bytes available" from __archive_read_ahead().
1175  *    Consume whatever you actually use.
1176  *  * "I want to output a large block of data."  As above, ask for 1 byte,
1177  *    emit all that's available (up to whatever limit you have), consume
1178  *    it all, then repeat until you're done.  This effectively means that
1179  *    you're passing along the blocks that came from your provider.
1180  *  * "I want to peek ahead by a large amount."  Ask for 4k or so, then
1181  *    double and repeat until you get an error or have enough.  Note
1182  *    that the I/O layer will likely end up expanding its copy buffer
1183  *    to fit your request, so use this technique cautiously.  This
1184  *    technique is used, for example, by some of the format tasting
1185  *    code that has uncertain look-ahead needs.
1186  */
1187
1188 /*
1189  * Looks ahead in the input stream:
1190  *  * If 'avail' pointer is provided, that returns number of bytes available
1191  *    in the current buffer, which may be much larger than requested.
1192  *  * If end-of-file, *avail gets set to zero.
1193  *  * If error, *avail gets error code.
1194  *  * If request can be met, returns pointer to data.
1195  *  * If minimum request cannot be met, returns NULL.
1196  *
1197  * Note: If you just want "some data", ask for 1 byte and pay attention
1198  * to *avail, which will have the actual amount available.  If you
1199  * know exactly how many bytes you need, just ask for that and treat
1200  * a NULL return as an error.
1201  *
1202  * Important:  This does NOT move the file pointer.  See
1203  * __archive_read_consume() below.
1204  */
1205 const void *
1206 __archive_read_ahead(struct archive_read *a, size_t min, ssize_t *avail)
1207 {
1208         return (__archive_read_filter_ahead(a->filter, min, avail));
1209 }
1210
1211 const void *
1212 __archive_read_filter_ahead(struct archive_read_filter *filter,
1213     size_t min, ssize_t *avail)
1214 {
1215         ssize_t bytes_read;
1216         size_t tocopy;
1217
1218         if (filter->fatal) {
1219                 if (avail)
1220                         *avail = ARCHIVE_FATAL;
1221                 return (NULL);
1222         }
1223
1224         /*
1225          * Keep pulling more data until we can satisfy the request.
1226          */
1227         for (;;) {
1228
1229                 /*
1230                  * If we can satisfy from the copy buffer (and the
1231                  * copy buffer isn't empty), we're done.  In particular,
1232                  * note that min == 0 is a perfectly well-defined
1233                  * request.
1234                  */
1235                 if (filter->avail >= min && filter->avail > 0) {
1236                         if (avail != NULL)
1237                                 *avail = filter->avail;
1238                         return (filter->next);
1239                 }
1240
1241                 /*
1242                  * We can satisfy directly from client buffer if everything
1243                  * currently in the copy buffer is still in the client buffer.
1244                  */
1245                 if (filter->client_total >= filter->client_avail + filter->avail
1246                     && filter->client_avail + filter->avail >= min) {
1247                         /* "Roll back" to client buffer. */
1248                         filter->client_avail += filter->avail;
1249                         filter->client_next -= filter->avail;
1250                         /* Copy buffer is now empty. */
1251                         filter->avail = 0;
1252                         filter->next = filter->buffer;
1253                         /* Return data from client buffer. */
1254                         if (avail != NULL)
1255                                 *avail = filter->client_avail;
1256                         return (filter->client_next);
1257                 }
1258
1259                 /* Move data forward in copy buffer if necessary. */
1260                 if (filter->next > filter->buffer &&
1261                     filter->next + min > filter->buffer + filter->buffer_size) {
1262                         if (filter->avail > 0)
1263                                 memmove(filter->buffer, filter->next,
1264                                     filter->avail);
1265                         filter->next = filter->buffer;
1266                 }
1267
1268                 /* If we've used up the client data, get more. */
1269                 if (filter->client_avail <= 0) {
1270                         if (filter->end_of_file) {
1271                                 if (avail != NULL)
1272                                         *avail = 0;
1273                                 return (NULL);
1274                         }
1275                         bytes_read = (filter->read)(filter,
1276                             &filter->client_buff);
1277                         if (bytes_read < 0) {           /* Read error. */
1278                                 filter->client_total = filter->client_avail = 0;
1279                                 filter->client_next =
1280                                     filter->client_buff = NULL;
1281                                 filter->fatal = 1;
1282                                 if (avail != NULL)
1283                                         *avail = ARCHIVE_FATAL;
1284                                 return (NULL);
1285                         }
1286                         if (bytes_read == 0) {
1287                                 /* Check for another client object first */
1288                                 if (filter->archive->client.cursor !=
1289                                       filter->archive->client.nodes - 1) {
1290                                         if (client_switch_proxy(filter,
1291                                             filter->archive->client.cursor + 1)
1292                                             == ARCHIVE_OK)
1293                                                 continue;
1294                                 }
1295                                 /* Premature end-of-file. */
1296                                 filter->client_total = filter->client_avail = 0;
1297                                 filter->client_next =
1298                                     filter->client_buff = NULL;
1299                                 filter->end_of_file = 1;
1300                                 /* Return whatever we do have. */
1301                                 if (avail != NULL)
1302                                         *avail = filter->avail;
1303                                 return (NULL);
1304                         }
1305                         filter->client_total = bytes_read;
1306                         filter->client_avail = filter->client_total;
1307                         filter->client_next = filter->client_buff;
1308                 } else {
1309                         /*
1310                          * We can't satisfy the request from the copy
1311                          * buffer or the existing client data, so we
1312                          * need to copy more client data over to the
1313                          * copy buffer.
1314                          */
1315
1316                         /* Ensure the buffer is big enough. */
1317                         if (min > filter->buffer_size) {
1318                                 size_t s, t;
1319                                 char *p;
1320
1321                                 /* Double the buffer; watch for overflow. */
1322                                 s = t = filter->buffer_size;
1323                                 if (s == 0)
1324                                         s = min;
1325                                 while (s < min) {
1326                                         t *= 2;
1327                                         if (t <= s) { /* Integer overflow! */
1328                                                 archive_set_error(
1329                                                     &filter->archive->archive,
1330                                                     ENOMEM,
1331                                                     "Unable to allocate copy"
1332                                                     " buffer");
1333                                                 filter->fatal = 1;
1334                                                 if (avail != NULL)
1335                                                         *avail = ARCHIVE_FATAL;
1336                                                 return (NULL);
1337                                         }
1338                                         s = t;
1339                                 }
1340                                 /* Now s >= min, so allocate a new buffer. */
1341                                 p = (char *)malloc(s);
1342                                 if (p == NULL) {
1343                                         archive_set_error(
1344                                                 &filter->archive->archive,
1345                                                 ENOMEM,
1346                                             "Unable to allocate copy buffer");
1347                                         filter->fatal = 1;
1348                                         if (avail != NULL)
1349                                                 *avail = ARCHIVE_FATAL;
1350                                         return (NULL);
1351                                 }
1352                                 /* Move data into newly-enlarged buffer. */
1353                                 if (filter->avail > 0)
1354                                         memmove(p, filter->next, filter->avail);
1355                                 free(filter->buffer);
1356                                 filter->next = filter->buffer = p;
1357                                 filter->buffer_size = s;
1358                         }
1359
1360                         /* We can add client data to copy buffer. */
1361                         /* First estimate: copy to fill rest of buffer. */
1362                         tocopy = (filter->buffer + filter->buffer_size)
1363                             - (filter->next + filter->avail);
1364                         /* Don't waste time buffering more than we need to. */
1365                         if (tocopy + filter->avail > min)
1366                                 tocopy = min - filter->avail;
1367                         /* Don't copy more than is available. */
1368                         if (tocopy > filter->client_avail)
1369                                 tocopy = filter->client_avail;
1370
1371                         memcpy(filter->next + filter->avail,
1372                             filter->client_next, tocopy);
1373                         /* Remove this data from client buffer. */
1374                         filter->client_next += tocopy;
1375                         filter->client_avail -= tocopy;
1376                         /* add it to copy buffer. */
1377                         filter->avail += tocopy;
1378                 }
1379         }
1380 }
1381
1382 /*
1383  * Move the file pointer forward.
1384  */
1385 int64_t
1386 __archive_read_consume(struct archive_read *a, int64_t request)
1387 {
1388         return (__archive_read_filter_consume(a->filter, request));
1389 }
1390
1391 int64_t
1392 __archive_read_filter_consume(struct archive_read_filter * filter,
1393     int64_t request)
1394 {
1395         int64_t skipped;
1396
1397         if (request == 0)
1398                 return 0;
1399
1400         skipped = advance_file_pointer(filter, request);
1401         if (skipped == request)
1402                 return (skipped);
1403         /* We hit EOF before we satisfied the skip request. */
1404         if (skipped < 0)  /* Map error code to 0 for error message below. */
1405                 skipped = 0;
1406         archive_set_error(&filter->archive->archive,
1407             ARCHIVE_ERRNO_MISC,
1408             "Truncated input file (needed %jd bytes, only %jd available)",
1409             (intmax_t)request, (intmax_t)skipped);
1410         return (ARCHIVE_FATAL);
1411 }
1412
1413 /*
1414  * Advance the file pointer by the amount requested.
1415  * Returns the amount actually advanced, which may be less than the
1416  * request if EOF is encountered first.
1417  * Returns a negative value if there's an I/O error.
1418  */
1419 static int64_t
1420 advance_file_pointer(struct archive_read_filter *filter, int64_t request)
1421 {
1422         int64_t bytes_skipped, total_bytes_skipped = 0;
1423         ssize_t bytes_read;
1424         size_t min;
1425
1426         if (filter->fatal)
1427                 return (-1);
1428
1429         /* Use up the copy buffer first. */
1430         if (filter->avail > 0) {
1431                 min = (size_t)minimum(request, (int64_t)filter->avail);
1432                 filter->next += min;
1433                 filter->avail -= min;
1434                 request -= min;
1435                 filter->position += min;
1436                 total_bytes_skipped += min;
1437         }
1438
1439         /* Then use up the client buffer. */
1440         if (filter->client_avail > 0) {
1441                 min = (size_t)minimum(request, (int64_t)filter->client_avail);
1442                 filter->client_next += min;
1443                 filter->client_avail -= min;
1444                 request -= min;
1445                 filter->position += min;
1446                 total_bytes_skipped += min;
1447         }
1448         if (request == 0)
1449                 return (total_bytes_skipped);
1450
1451         /* If there's an optimized skip function, use it. */
1452         if (filter->skip != NULL) {
1453                 bytes_skipped = (filter->skip)(filter, request);
1454                 if (bytes_skipped < 0) {        /* error */
1455                         filter->fatal = 1;
1456                         return (bytes_skipped);
1457                 }
1458                 filter->position += bytes_skipped;
1459                 total_bytes_skipped += bytes_skipped;
1460                 request -= bytes_skipped;
1461                 if (request == 0)
1462                         return (total_bytes_skipped);
1463         }
1464
1465         /* Use ordinary reads as necessary to complete the request. */
1466         for (;;) {
1467                 bytes_read = (filter->read)(filter, &filter->client_buff);
1468                 if (bytes_read < 0) {
1469                         filter->client_buff = NULL;
1470                         filter->fatal = 1;
1471                         return (bytes_read);
1472                 }
1473
1474                 if (bytes_read == 0) {
1475                         if (filter->archive->client.cursor !=
1476                               filter->archive->client.nodes - 1) {
1477                                 if (client_switch_proxy(filter,
1478                                     filter->archive->client.cursor + 1)
1479                                     == ARCHIVE_OK)
1480                                         continue;
1481                         }
1482                         filter->client_buff = NULL;
1483                         filter->end_of_file = 1;
1484                         return (total_bytes_skipped);
1485                 }
1486
1487                 if (bytes_read >= request) {
1488                         filter->client_next =
1489                             ((const char *)filter->client_buff) + request;
1490                         filter->client_avail = (size_t)(bytes_read - request);
1491                         filter->client_total = bytes_read;
1492                         total_bytes_skipped += request;
1493                         filter->position += request;
1494                         return (total_bytes_skipped);
1495                 }
1496
1497                 filter->position += bytes_read;
1498                 total_bytes_skipped += bytes_read;
1499                 request -= bytes_read;
1500         }
1501 }
1502
1503 /**
1504  * Returns ARCHIVE_FAILED if seeking isn't supported.
1505  */
1506 int64_t
1507 __archive_read_seek(struct archive_read *a, int64_t offset, int whence)
1508 {
1509         return __archive_read_filter_seek(a->filter, offset, whence);
1510 }
1511
1512 int64_t
1513 __archive_read_filter_seek(struct archive_read_filter *filter, int64_t offset,
1514     int whence)
1515 {
1516         struct archive_read_client *client;
1517         int64_t r;
1518         unsigned int cursor;
1519
1520         if (filter->closed || filter->fatal)
1521                 return (ARCHIVE_FATAL);
1522         if (filter->seek == NULL)
1523                 return (ARCHIVE_FAILED);
1524
1525         client = &(filter->archive->client);
1526         switch (whence) {
1527         case SEEK_CUR:
1528                 /* Adjust the offset and use SEEK_SET instead */
1529                 offset += filter->position;
1530         case SEEK_SET:
1531                 cursor = 0;
1532                 while (1)
1533                 {
1534                         if (client->dataset[cursor].begin_position < 0 ||
1535                             client->dataset[cursor].total_size < 0 ||
1536                             client->dataset[cursor].begin_position +
1537                               client->dataset[cursor].total_size - 1 > offset ||
1538                             cursor + 1 >= client->nodes)
1539                                 break;
1540                         r = client->dataset[cursor].begin_position +
1541                                 client->dataset[cursor].total_size;
1542                         client->dataset[++cursor].begin_position = r;
1543                 }
1544                 while (1) {
1545                         r = client_switch_proxy(filter, cursor);
1546                         if (r != ARCHIVE_OK)
1547                                 return r;
1548                         if ((r = client_seek_proxy(filter, 0, SEEK_END)) < 0)
1549                                 return r;
1550                         client->dataset[cursor].total_size = r;
1551                         if (client->dataset[cursor].begin_position +
1552                             client->dataset[cursor].total_size - 1 > offset ||
1553                             cursor + 1 >= client->nodes)
1554                                 break;
1555                         r = client->dataset[cursor].begin_position +
1556                                 client->dataset[cursor].total_size;
1557                         client->dataset[++cursor].begin_position = r;
1558                 }
1559                 offset -= client->dataset[cursor].begin_position;
1560                 if (offset < 0)
1561                         offset = 0;
1562                 else if (offset > client->dataset[cursor].total_size - 1)
1563                         offset = client->dataset[cursor].total_size - 1;
1564                 if ((r = client_seek_proxy(filter, offset, SEEK_SET)) < 0)
1565                         return r;
1566                 break;
1567
1568         case SEEK_END:
1569                 cursor = 0;
1570                 while (1) {
1571                         if (client->dataset[cursor].begin_position < 0 ||
1572                             client->dataset[cursor].total_size < 0 ||
1573                             cursor + 1 >= client->nodes)
1574                                 break;
1575                         r = client->dataset[cursor].begin_position +
1576                                 client->dataset[cursor].total_size;
1577                         client->dataset[++cursor].begin_position = r;
1578                 }
1579                 while (1) {
1580                         r = client_switch_proxy(filter, cursor);
1581                         if (r != ARCHIVE_OK)
1582                                 return r;
1583                         if ((r = client_seek_proxy(filter, 0, SEEK_END)) < 0)
1584                                 return r;
1585                         client->dataset[cursor].total_size = r;
1586                         r = client->dataset[cursor].begin_position +
1587                                 client->dataset[cursor].total_size;
1588                         if (cursor + 1 >= client->nodes)
1589                                 break;
1590                         client->dataset[++cursor].begin_position = r;
1591                 }
1592                 while (1) {
1593                         if (r + offset >=
1594                             client->dataset[cursor].begin_position)
1595                                 break;
1596                         offset += client->dataset[cursor].total_size;
1597                         if (cursor == 0)
1598                                 break;
1599                         cursor--;
1600                         r = client->dataset[cursor].begin_position +
1601                                 client->dataset[cursor].total_size;
1602                 }
1603                 offset = (r + offset) - client->dataset[cursor].begin_position;
1604                 if ((r = client_switch_proxy(filter, cursor)) != ARCHIVE_OK)
1605                         return r;
1606                 r = client_seek_proxy(filter, offset, SEEK_SET);
1607                 if (r < ARCHIVE_OK)
1608                         return r;
1609                 break;
1610
1611         default:
1612                 return (ARCHIVE_FATAL);
1613         }
1614         r += client->dataset[cursor].begin_position;
1615
1616         if (r >= 0) {
1617                 /*
1618                  * Ouch.  Clearing the buffer like this hurts, especially
1619                  * at bid time.  A lot of our efficiency at bid time comes
1620                  * from having bidders reuse the data we've already read.
1621                  *
1622                  * TODO: If the seek request is in data we already
1623                  * have, then don't call the seek callback.
1624                  *
1625                  * TODO: Zip seeks to end-of-file at bid time.  If
1626                  * other formats also start doing this, we may need to
1627                  * find a way for clients to fudge the seek offset to
1628                  * a block boundary.
1629                  *
1630                  * Hmmm... If whence was SEEK_END, we know the file
1631                  * size is (r - offset).  Can we use that to simplify
1632                  * the TODO items above?
1633                  */
1634                 filter->avail = filter->client_avail = 0;
1635                 filter->next = filter->buffer;
1636                 filter->position = r;
1637                 filter->end_of_file = 0;
1638         }
1639         return r;
1640 }