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
36 #ifdef HAVE_ERRNO_H
37 #include <errno.h>
38 #endif
39 #include <stdio.h>
40 #ifdef HAVE_STDLIB_H
41 #include <stdlib.h>
42 #endif
43 #ifdef HAVE_STRING_H
44 #include <string.h>
45 #endif
46 #ifdef HAVE_UNISTD_H
47 #include <unistd.h>
48 #endif
49
50 #include "archive.h"
51 #include "archive_entry.h"
52 #include "archive_private.h"
53 #include "archive_read_private.h"
54
55 #define minimum(a, b) (a < b ? a : b)
56
57 static int choose_filters(struct archive_read *);
58 static int choose_format(struct archive_read *);
59 static int close_filters(struct archive_read *);
60 static int64_t _archive_filter_bytes(struct archive *, int);
61 static int _archive_filter_code(struct archive *, int);
62 static const char *_archive_filter_name(struct archive *, int);
63 static int _archive_filter_count(struct archive *);
64 static int _archive_read_close(struct archive *);
65 static int _archive_read_data_block(struct archive *,
66 const void **, size_t *, int64_t *);
67 static int _archive_read_free(struct archive *);
68 static int _archive_read_next_header(struct archive *,
69 struct archive_entry **);
70 static int _archive_read_next_header2(struct archive *,
71 struct archive_entry *);
72 static int64_t advance_file_pointer(struct archive_read_filter *, int64_t);
73
74 static const struct archive_vtable
75 archive_read_vtable = {
76 .archive_filter_bytes = _archive_filter_bytes,
77 .archive_filter_code = _archive_filter_code,
78 .archive_filter_name = _archive_filter_name,
79 .archive_filter_count = _archive_filter_count,
80 .archive_read_data_block = _archive_read_data_block,
81 .archive_read_next_header = _archive_read_next_header,
82 .archive_read_next_header2 = _archive_read_next_header2,
83 .archive_free = _archive_read_free,
84 .archive_close = _archive_read_close,
85 };
86
87 /*
88 * Allocate, initialize and return a struct archive object.
89 */
90 struct archive *
archive_read_new(void)91 archive_read_new(void)
92 {
93 struct archive_read *a;
94
95 a = calloc(1, sizeof(*a));
96 if (a == NULL)
97 return (NULL);
98 a->archive.magic = ARCHIVE_READ_MAGIC;
99
100 a->archive.state = ARCHIVE_STATE_NEW;
101 a->entry = archive_entry_new2(&a->archive);
102 a->archive.vtable = &archive_read_vtable;
103
104 a->passphrases.last = &a->passphrases.first;
105
106 return (&a->archive);
107 }
108
109 /*
110 * Record the do-not-extract-to file. This belongs in archive_read_extract.c.
111 */
112 void
archive_read_extract_set_skip_file(struct archive * _a,la_int64_t d,la_int64_t i)113 archive_read_extract_set_skip_file(struct archive *_a, la_int64_t d,
114 la_int64_t i)
115 {
116 struct archive_read *a = (struct archive_read *)_a;
117
118 if (ARCHIVE_OK != __archive_check_magic(_a, ARCHIVE_READ_MAGIC,
119 ARCHIVE_STATE_ANY, "archive_read_extract_set_skip_file"))
120 return;
121 a->skip_file_set = 1;
122 a->skip_file_dev = d;
123 a->skip_file_ino = i;
124 }
125
126 /*
127 * Open the archive
128 */
129 int
archive_read_open(struct archive * a,void * client_data,archive_open_callback * client_opener,archive_read_callback * client_reader,archive_close_callback * client_closer)130 archive_read_open(struct archive *a, void *client_data,
131 archive_open_callback *client_opener, archive_read_callback *client_reader,
132 archive_close_callback *client_closer)
133 {
134 /* Old archive_read_open() is just a thin shell around
135 * archive_read_open1. */
136 archive_read_set_open_callback(a, client_opener);
137 archive_read_set_read_callback(a, client_reader);
138 archive_read_set_close_callback(a, client_closer);
139 archive_read_set_callback_data(a, client_data);
140 return archive_read_open1(a);
141 }
142
143
144 int
archive_read_open2(struct archive * a,void * client_data,archive_open_callback * client_opener,archive_read_callback * client_reader,archive_skip_callback * client_skipper,archive_close_callback * client_closer)145 archive_read_open2(struct archive *a, void *client_data,
146 archive_open_callback *client_opener,
147 archive_read_callback *client_reader,
148 archive_skip_callback *client_skipper,
149 archive_close_callback *client_closer)
150 {
151 /* Old archive_read_open2() is just a thin shell around
152 * archive_read_open1. */
153 archive_read_set_callback_data(a, client_data);
154 archive_read_set_open_callback(a, client_opener);
155 archive_read_set_read_callback(a, client_reader);
156 archive_read_set_skip_callback(a, client_skipper);
157 archive_read_set_close_callback(a, client_closer);
158 return archive_read_open1(a);
159 }
160
161 static ssize_t
client_read_proxy(struct archive_read_filter * self,const void ** buff)162 client_read_proxy(struct archive_read_filter *self, const void **buff)
163 {
164 ssize_t r;
165 r = (self->archive->client.reader)(&self->archive->archive,
166 self->data, buff);
167 return (r);
168 }
169
170 static int64_t
client_skip_proxy(struct archive_read_filter * self,int64_t request)171 client_skip_proxy(struct archive_read_filter *self, int64_t request)
172 {
173 if (request < 0)
174 __archive_errx(1, "Negative skip requested.");
175 if (request == 0)
176 return 0;
177
178 if (self->archive->client.skipper != NULL) {
179 int64_t total = 0;
180 for (;;) {
181 int64_t get, ask = request;
182 get = (self->archive->client.skipper)
183 (&self->archive->archive, self->data, ask);
184 total += get;
185 if (get == 0 || get == request)
186 return (total);
187 if (get > request)
188 return ARCHIVE_FATAL;
189 request -= get;
190 }
191 } else if (self->archive->client.seeker != NULL
192 && request > 64 * 1024) {
193 /* If the client provided a seeker but not a skipper,
194 * we can use the seeker to skip forward.
195 *
196 * Note: This isn't always a good idea. The client
197 * skipper is allowed to skip by less than requested
198 * if it needs to maintain block alignment. The
199 * seeker is not allowed to play such games, so using
200 * the seeker here may be a performance loss compared
201 * to just reading and discarding. That's why we
202 * only do this for skips of over 64k.
203 */
204 int64_t before = self->position;
205 int64_t after = (self->archive->client.seeker)
206 (&self->archive->archive, self->data, request, SEEK_CUR);
207 if (after != before + request)
208 return ARCHIVE_FATAL;
209 return after - before;
210 }
211 return 0;
212 }
213
214 static int64_t
client_seek_proxy(struct archive_read_filter * self,int64_t offset,int whence)215 client_seek_proxy(struct archive_read_filter *self, int64_t offset, int whence)
216 {
217 /* DO NOT use the skipper here! If we transparently handled
218 * forward seek here by using the skipper, that will break
219 * other libarchive code that assumes a successful forward
220 * seek means it can also seek backwards.
221 */
222 if (self->archive->client.seeker == NULL) {
223 archive_set_error(&self->archive->archive, ARCHIVE_ERRNO_MISC,
224 "Current client reader does not support seeking a device");
225 return (ARCHIVE_FAILED);
226 }
227 return (self->archive->client.seeker)(&self->archive->archive,
228 self->data, offset, whence);
229 }
230
231 static int
read_client_close_proxy(struct archive_read * a)232 read_client_close_proxy(struct archive_read *a)
233 {
234 int r = ARCHIVE_OK, r2;
235 unsigned int i;
236
237 if (a->client.closer == NULL)
238 return (r);
239 for (i = 0; i < a->client.nodes; i++)
240 {
241 r2 = (a->client.closer)
242 ((struct archive *)a, a->client.dataset[i].data);
243 if (r > r2)
244 r = r2;
245 }
246 return (r);
247 }
248
249 static int
client_close_proxy(struct archive_read_filter * self)250 client_close_proxy(struct archive_read_filter *self)
251 {
252 return read_client_close_proxy(self->archive);
253 }
254
255 static int
client_open_proxy(struct archive_read_filter * self)256 client_open_proxy(struct archive_read_filter *self)
257 {
258 int r = ARCHIVE_OK;
259 if (self->archive->client.opener != NULL)
260 r = (self->archive->client.opener)(
261 (struct archive *)self->archive, self->data);
262 return (r);
263 }
264
265 static int
client_switch_proxy(struct archive_read_filter * self,unsigned int iindex)266 client_switch_proxy(struct archive_read_filter *self, unsigned int iindex)
267 {
268 int r1 = ARCHIVE_OK, r2 = ARCHIVE_OK;
269 void *data2 = NULL;
270
271 /* Don't do anything if already in the specified data node */
272 if (self->archive->client.cursor == iindex)
273 return (ARCHIVE_OK);
274
275 self->archive->client.cursor = iindex;
276 data2 = self->archive->client.dataset[self->archive->client.cursor].data;
277 if (self->archive->client.switcher != NULL)
278 {
279 r1 = r2 = (self->archive->client.switcher)
280 ((struct archive *)self->archive, self->data, data2);
281 self->data = data2;
282 }
283 else
284 {
285 /* Attempt to call close and open instead */
286 if (self->archive->client.closer != NULL)
287 r1 = (self->archive->client.closer)
288 ((struct archive *)self->archive, self->data);
289 self->data = data2;
290 r2 = client_open_proxy(self);
291 }
292 return (r1 < r2) ? r1 : r2;
293 }
294
295 int
archive_read_set_open_callback(struct archive * _a,archive_open_callback * client_opener)296 archive_read_set_open_callback(struct archive *_a,
297 archive_open_callback *client_opener)
298 {
299 struct archive_read *a = (struct archive_read *)_a;
300 archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
301 "archive_read_set_open_callback");
302 a->client.opener = client_opener;
303 return ARCHIVE_OK;
304 }
305
306 int
archive_read_set_read_callback(struct archive * _a,archive_read_callback * client_reader)307 archive_read_set_read_callback(struct archive *_a,
308 archive_read_callback *client_reader)
309 {
310 struct archive_read *a = (struct archive_read *)_a;
311 archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
312 "archive_read_set_read_callback");
313 a->client.reader = client_reader;
314 return ARCHIVE_OK;
315 }
316
317 int
archive_read_set_skip_callback(struct archive * _a,archive_skip_callback * client_skipper)318 archive_read_set_skip_callback(struct archive *_a,
319 archive_skip_callback *client_skipper)
320 {
321 struct archive_read *a = (struct archive_read *)_a;
322 archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
323 "archive_read_set_skip_callback");
324 a->client.skipper = client_skipper;
325 return ARCHIVE_OK;
326 }
327
328 int
archive_read_set_seek_callback(struct archive * _a,archive_seek_callback * client_seeker)329 archive_read_set_seek_callback(struct archive *_a,
330 archive_seek_callback *client_seeker)
331 {
332 struct archive_read *a = (struct archive_read *)_a;
333 archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
334 "archive_read_set_seek_callback");
335 a->client.seeker = client_seeker;
336 return ARCHIVE_OK;
337 }
338
339 int
archive_read_set_close_callback(struct archive * _a,archive_close_callback * client_closer)340 archive_read_set_close_callback(struct archive *_a,
341 archive_close_callback *client_closer)
342 {
343 struct archive_read *a = (struct archive_read *)_a;
344 archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
345 "archive_read_set_close_callback");
346 a->client.closer = client_closer;
347 return ARCHIVE_OK;
348 }
349
350 int
archive_read_set_switch_callback(struct archive * _a,archive_switch_callback * client_switcher)351 archive_read_set_switch_callback(struct archive *_a,
352 archive_switch_callback *client_switcher)
353 {
354 struct archive_read *a = (struct archive_read *)_a;
355 archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
356 "archive_read_set_switch_callback");
357 a->client.switcher = client_switcher;
358 return ARCHIVE_OK;
359 }
360
361 int
archive_read_set_callback_data(struct archive * _a,void * client_data)362 archive_read_set_callback_data(struct archive *_a, void *client_data)
363 {
364 return archive_read_set_callback_data2(_a, client_data, 0);
365 }
366
367 int
archive_read_set_callback_data2(struct archive * _a,void * client_data,unsigned int iindex)368 archive_read_set_callback_data2(struct archive *_a, void *client_data,
369 unsigned int iindex)
370 {
371 struct archive_read *a = (struct archive_read *)_a;
372 archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
373 "archive_read_set_callback_data2");
374
375 if (a->client.nodes == 0)
376 {
377 a->client.dataset = (struct archive_read_data_node *)
378 calloc(1, sizeof(*a->client.dataset));
379 if (a->client.dataset == NULL)
380 {
381 archive_set_error(&a->archive, ENOMEM,
382 "No memory.");
383 return ARCHIVE_FATAL;
384 }
385 a->client.nodes = 1;
386 }
387
388 if (iindex > a->client.nodes - 1)
389 {
390 archive_set_error(&a->archive, EINVAL,
391 "Invalid index specified.");
392 return ARCHIVE_FATAL;
393 }
394 a->client.dataset[iindex].data = client_data;
395 a->client.dataset[iindex].begin_position = -1;
396 a->client.dataset[iindex].total_size = -1;
397 return ARCHIVE_OK;
398 }
399
400 int
archive_read_add_callback_data(struct archive * _a,void * client_data,unsigned int iindex)401 archive_read_add_callback_data(struct archive *_a, void *client_data,
402 unsigned int iindex)
403 {
404 struct archive_read *a = (struct archive_read *)_a;
405 void *p;
406 unsigned int i;
407
408 archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
409 "archive_read_add_callback_data");
410 if (iindex > a->client.nodes) {
411 archive_set_error(&a->archive, EINVAL,
412 "Invalid index specified.");
413 return ARCHIVE_FATAL;
414 }
415 p = realloc(a->client.dataset, sizeof(*a->client.dataset)
416 * (++(a->client.nodes)));
417 if (p == NULL) {
418 archive_set_error(&a->archive, ENOMEM,
419 "No memory.");
420 return ARCHIVE_FATAL;
421 }
422 a->client.dataset = (struct archive_read_data_node *)p;
423 for (i = a->client.nodes - 1; i > iindex; i--) {
424 a->client.dataset[i].data = a->client.dataset[i-1].data;
425 a->client.dataset[i].begin_position = -1;
426 a->client.dataset[i].total_size = -1;
427 }
428 a->client.dataset[iindex].data = client_data;
429 a->client.dataset[iindex].begin_position = -1;
430 a->client.dataset[iindex].total_size = -1;
431 return ARCHIVE_OK;
432 }
433
434 int
archive_read_append_callback_data(struct archive * _a,void * client_data)435 archive_read_append_callback_data(struct archive *_a, void *client_data)
436 {
437 struct archive_read *a = (struct archive_read *)_a;
438 return archive_read_add_callback_data(_a, client_data, a->client.nodes);
439 }
440
441 int
archive_read_prepend_callback_data(struct archive * _a,void * client_data)442 archive_read_prepend_callback_data(struct archive *_a, void *client_data)
443 {
444 return archive_read_add_callback_data(_a, client_data, 0);
445 }
446
447 static const struct archive_read_filter_vtable
448 none_reader_vtable = {
449 .read = client_read_proxy,
450 .close = client_close_proxy,
451 };
452
453 int
archive_read_open1(struct archive * _a)454 archive_read_open1(struct archive *_a)
455 {
456 struct archive_read *a = (struct archive_read *)_a;
457 struct archive_read_filter *filter, *tmp;
458 int slot, e = ARCHIVE_OK;
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 read_client_close_proxy(a);
477 return (e);
478 }
479 }
480
481 filter = calloc(1, sizeof(*filter));
482 if (filter == NULL)
483 return (ARCHIVE_FATAL);
484 filter->bidder = NULL;
485 filter->upstream = NULL;
486 filter->archive = a;
487 filter->data = a->client.dataset[0].data;
488 filter->vtable = &none_reader_vtable;
489 filter->name = "none";
490 filter->code = ARCHIVE_FILTER_NONE;
491 filter->can_skip = 1;
492 filter->can_seek = 1;
493
494 a->client.dataset[0].begin_position = 0;
495 if (!a->filter || !a->bypass_filter_bidding)
496 {
497 a->filter = filter;
498 /* Build out the input pipeline. */
499 e = choose_filters(a);
500 if (e < ARCHIVE_WARN) {
501 a->archive.state = ARCHIVE_STATE_FATAL;
502 return (ARCHIVE_FATAL);
503 }
504 }
505 else
506 {
507 /* Need to add "NONE" type filter at the end of the filter chain */
508 tmp = a->filter;
509 while (tmp->upstream)
510 tmp = tmp->upstream;
511 tmp->upstream = filter;
512 }
513
514 if (!a->format)
515 {
516 slot = choose_format(a);
517 if (slot < 0) {
518 close_filters(a);
519 a->archive.state = ARCHIVE_STATE_FATAL;
520 return (ARCHIVE_FATAL);
521 }
522 a->format = &(a->formats[slot]);
523 }
524
525 a->archive.state = ARCHIVE_STATE_HEADER;
526
527 /* Ensure libarchive starts from the first node in a multivolume set */
528 client_switch_proxy(a->filter, 0);
529 return (e);
530 }
531
532 /*
533 * Allow each registered stream transform to bid on whether
534 * it wants to handle this stream. Repeat until we've finished
535 * building the pipeline.
536 */
537
538 /* We won't build a filter pipeline with more stages than this. */
539 #define MAX_NUMBER_FILTERS 25
540
541 static int
choose_filters(struct archive_read * a)542 choose_filters(struct archive_read *a)
543 {
544 int number_bidders, i, bid, best_bid, number_filters;
545 struct archive_read_filter_bidder *bidder, *best_bidder;
546 struct archive_read_filter *filter;
547 ssize_t avail;
548 int r;
549
550 for (number_filters = 0; number_filters < MAX_NUMBER_FILTERS; ++number_filters) {
551 number_bidders = sizeof(a->bidders) / sizeof(a->bidders[0]);
552
553 best_bid = 0;
554 best_bidder = NULL;
555
556 bidder = a->bidders;
557 for (i = 0; i < number_bidders; i++, bidder++) {
558 if (bidder->vtable == NULL)
559 continue;
560 bid = (bidder->vtable->bid)(bidder, a->filter);
561 if (bid > best_bid) {
562 best_bid = bid;
563 best_bidder = bidder;
564 }
565 }
566
567 /* If no bidder, we're done. */
568 if (best_bidder == NULL) {
569 /* Verify the filter by asking it for some data. */
570 __archive_read_filter_ahead(a->filter, 1, &avail);
571 if (avail < 0) {
572 __archive_read_free_filters(a);
573 return (ARCHIVE_FATAL);
574 }
575 return (ARCHIVE_OK);
576 }
577
578 filter = calloc(1, sizeof(*filter));
579 if (filter == NULL)
580 return (ARCHIVE_FATAL);
581 filter->bidder = best_bidder;
582 filter->archive = a;
583 filter->upstream = a->filter;
584 a->filter = filter;
585 r = (best_bidder->vtable->init)(a->filter);
586 if (r != ARCHIVE_OK) {
587 __archive_read_free_filters(a);
588 return (ARCHIVE_FATAL);
589 }
590 }
591 archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
592 "Input requires too many filters for decoding");
593 return (ARCHIVE_FATAL);
594 }
595
596 int
__archive_read_header(struct archive_read * a,struct archive_entry * entry)597 __archive_read_header(struct archive_read *a, struct archive_entry *entry)
598 {
599 if (!a->filter->vtable->read_header)
600 return (ARCHIVE_OK);
601 return a->filter->vtable->read_header(a->filter, entry);
602 }
603
604 /*
605 * Read header of next entry.
606 */
607 static int
_archive_read_next_header2(struct archive * _a,struct archive_entry * entry)608 _archive_read_next_header2(struct archive *_a, struct archive_entry *entry)
609 {
610 struct archive_read *a = (struct archive_read *)_a;
611 int r1 = ARCHIVE_OK, r2;
612
613 archive_check_magic(_a, ARCHIVE_READ_MAGIC,
614 ARCHIVE_STATE_HEADER | ARCHIVE_STATE_DATA,
615 "archive_read_next_header");
616
617 archive_entry_clear(entry);
618 archive_clear_error(&a->archive);
619
620 /*
621 * If client didn't consume entire data, skip any remainder
622 * (This is especially important for GNU incremental directories.)
623 */
624 if (a->archive.state == ARCHIVE_STATE_DATA) {
625 r1 = archive_read_data_skip(&a->archive);
626 if (r1 == ARCHIVE_EOF)
627 archive_set_error(&a->archive, EIO,
628 "Premature end-of-file.");
629 if (r1 == ARCHIVE_EOF || r1 == ARCHIVE_FATAL) {
630 a->archive.state = ARCHIVE_STATE_FATAL;
631 return (ARCHIVE_FATAL);
632 }
633 }
634
635 /* Record start-of-header offset in uncompressed stream. */
636 a->header_position = a->filter->position;
637
638 ++_a->file_count;
639 r2 = (a->format->read_header)(a, entry);
640
641 /*
642 * EOF and FATAL are persistent at this layer. By
643 * modifying the state, we guarantee that future calls to
644 * read a header or read data will fail.
645 */
646 switch (r2) {
647 case ARCHIVE_EOF:
648 a->archive.state = ARCHIVE_STATE_EOF;
649 --_a->file_count;/* Revert a file counter. */
650 break;
651 case ARCHIVE_OK:
652 a->archive.state = ARCHIVE_STATE_DATA;
653 break;
654 case ARCHIVE_WARN:
655 a->archive.state = ARCHIVE_STATE_DATA;
656 break;
657 case ARCHIVE_RETRY:
658 break;
659 case ARCHIVE_FATAL:
660 a->archive.state = ARCHIVE_STATE_FATAL;
661 break;
662 }
663
664 __archive_reset_read_data(&a->archive);
665
666 a->data_start_node = a->client.cursor;
667 /* EOF always wins; otherwise return the worst error. */
668 return (r2 < r1 || r2 == ARCHIVE_EOF) ? r2 : r1;
669 }
670
671 static int
_archive_read_next_header(struct archive * _a,struct archive_entry ** entryp)672 _archive_read_next_header(struct archive *_a, struct archive_entry **entryp)
673 {
674 int ret;
675 struct archive_read *a = (struct archive_read *)_a;
676 *entryp = NULL;
677 ret = _archive_read_next_header2(_a, a->entry);
678 *entryp = a->entry;
679 return ret;
680 }
681
682 /*
683 * Allow each registered format to bid on whether it wants to handle
684 * the next entry. Return index of winning bidder.
685 */
686 static int
choose_format(struct archive_read * a)687 choose_format(struct archive_read *a)
688 {
689 int slots;
690 int i;
691 int bid, best_bid;
692 int best_bid_slot;
693
694 slots = sizeof(a->formats) / sizeof(a->formats[0]);
695 best_bid = -1;
696 best_bid_slot = -1;
697
698 /* Set up a->format for convenience of bidders. */
699 a->format = &(a->formats[0]);
700 for (i = 0; i < slots; i++, a->format++) {
701 if (a->format->bid) {
702 bid = (a->format->bid)(a, best_bid);
703 if (bid == ARCHIVE_FATAL)
704 return (ARCHIVE_FATAL);
705 if (a->filter->position != 0)
706 __archive_read_seek(a, 0, SEEK_SET);
707 if ((bid > best_bid) || (best_bid_slot < 0)) {
708 best_bid = bid;
709 best_bid_slot = i;
710 }
711 }
712 }
713
714 /*
715 * There were no bidders; this is a serious programmer error
716 * and demands a quick and definitive abort.
717 */
718 if (best_bid_slot < 0) {
719 archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
720 "No formats registered");
721 return (ARCHIVE_FATAL);
722 }
723
724 /*
725 * There were bidders, but no non-zero bids; this means we
726 * can't support this stream.
727 */
728 if (best_bid < 1) {
729 archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
730 "Unrecognized archive format");
731 return (ARCHIVE_FATAL);
732 }
733
734 return (best_bid_slot);
735 }
736
737 /*
738 * Return the file offset (within the uncompressed data stream) where
739 * the last header started.
740 */
741 la_int64_t
archive_read_header_position(struct archive * _a)742 archive_read_header_position(struct archive *_a)
743 {
744 struct archive_read *a = (struct archive_read *)_a;
745 archive_check_magic(_a, ARCHIVE_READ_MAGIC,
746 ARCHIVE_STATE_ANY, "archive_read_header_position");
747 return (a->header_position);
748 }
749
750 /*
751 * Returns 1 if the archive contains at least one encrypted entry.
752 * If the archive format not support encryption at all
753 * ARCHIVE_READ_FORMAT_ENCRYPTION_UNSUPPORTED is returned.
754 * If for any other reason (e.g. not enough data read so far)
755 * we cannot say whether there are encrypted entries, then
756 * ARCHIVE_READ_FORMAT_ENCRYPTION_DONT_KNOW is returned.
757 * In general, this function will return values below zero when the
758 * reader is uncertain or totally incapable of encryption support.
759 * When this function returns 0 you can be sure that the reader
760 * supports encryption detection but no encrypted entries have
761 * been found yet.
762 *
763 * NOTE: If the metadata/header of an archive is also encrypted, you
764 * cannot rely on the number of encrypted entries. That is why this
765 * function does not return the number of encrypted entries but#
766 * just shows that there are some.
767 */
768 int
archive_read_has_encrypted_entries(struct archive * _a)769 archive_read_has_encrypted_entries(struct archive *_a)
770 {
771 struct archive_read *a = (struct archive_read *)_a;
772 int format_supports_encryption = archive_read_format_capabilities(_a)
773 & (ARCHIVE_READ_FORMAT_CAPS_ENCRYPT_DATA | ARCHIVE_READ_FORMAT_CAPS_ENCRYPT_METADATA);
774
775 if (!_a || !format_supports_encryption) {
776 /* Format in general doesn't support encryption */
777 return ARCHIVE_READ_FORMAT_ENCRYPTION_UNSUPPORTED;
778 }
779
780 /* A reader potentially has read enough data now. */
781 if (a->format && a->format->has_encrypted_entries) {
782 return (a->format->has_encrypted_entries)(a);
783 }
784
785 /* For any other reason we cannot say how many entries are there. */
786 return ARCHIVE_READ_FORMAT_ENCRYPTION_DONT_KNOW;
787 }
788
789 /*
790 * Returns a bitmask of capabilities that are supported by the archive format reader.
791 * If the reader has no special capabilities, ARCHIVE_READ_FORMAT_CAPS_NONE is returned.
792 */
793 int
archive_read_format_capabilities(struct archive * _a)794 archive_read_format_capabilities(struct archive *_a)
795 {
796 struct archive_read *a = (struct archive_read *)_a;
797 if (a && a->format && a->format->format_capabilties) {
798 return (a->format->format_capabilties)(a);
799 }
800 return ARCHIVE_READ_FORMAT_CAPS_NONE;
801 }
802
803 /*
804 * Read data from an archive entry, using a read(2)-style interface.
805 * This is a convenience routine that just calls
806 * archive_read_data_block and copies the results into the client
807 * buffer, filling any gaps with zero bytes. Clients using this
808 * API can be completely ignorant of sparse-file issues; sparse files
809 * will simply be padded with nulls.
810 *
811 * DO NOT intermingle calls to this function and archive_read_data_block
812 * to read a single entry body.
813 */
814 la_ssize_t
archive_read_data(struct archive * _a,void * buff,size_t s)815 archive_read_data(struct archive *_a, void *buff, size_t s)
816 {
817 struct archive *a = (struct archive *)_a;
818 char *dest;
819 const void *read_buf;
820 size_t bytes_read;
821 size_t len;
822 int r;
823
824 bytes_read = 0;
825 dest = (char *)buff;
826
827 while (s > 0) {
828 if (a->read_data_offset == a->read_data_output_offset &&
829 a->read_data_remaining == 0) {
830 read_buf = a->read_data_block;
831 a->read_data_is_posix_read = 1;
832 a->read_data_requested = s;
833 r = archive_read_data_block(a, &read_buf,
834 &a->read_data_remaining, &a->read_data_offset);
835 a->read_data_block = read_buf;
836 if (r == ARCHIVE_EOF &&
837 a->read_data_offset == a->read_data_output_offset &&
838 a->read_data_remaining == 0)
839 return (bytes_read);
840 /*
841 * Error codes are all negative, so the status
842 * return here cannot be confused with a valid
843 * byte count. (ARCHIVE_OK is zero.)
844 */
845 if (r < ARCHIVE_OK)
846 return (r);
847 }
848
849 if (a->read_data_offset < a->read_data_output_offset) {
850 archive_set_error(a, ARCHIVE_ERRNO_FILE_FORMAT,
851 "Encountered out-of-order sparse blocks");
852 return (ARCHIVE_RETRY);
853 }
854
855 /* Compute the amount of zero padding needed. */
856 if (a->read_data_output_offset + (int64_t)s <
857 a->read_data_offset) {
858 len = s;
859 } else if (a->read_data_output_offset <
860 a->read_data_offset) {
861 len = (size_t)(a->read_data_offset -
862 a->read_data_output_offset);
863 } else
864 len = 0;
865
866 /* Add zeroes. */
867 memset(dest, 0, len);
868 s -= len;
869 a->read_data_output_offset += len;
870 dest += len;
871 bytes_read += len;
872
873 /* Copy data if there is any space left. */
874 if (s > 0) {
875 len = a->read_data_remaining;
876 if (len > s)
877 len = s;
878 if (len) {
879 memcpy(dest, a->read_data_block, len);
880 s -= len;
881 a->read_data_block += len;
882 a->read_data_remaining -= len;
883 a->read_data_output_offset += len;
884 a->read_data_offset += len;
885 dest += len;
886 bytes_read += len;
887 }
888 }
889 }
890 a->read_data_is_posix_read = 0;
891 a->read_data_requested = 0;
892 return (bytes_read);
893 }
894
895 /*
896 * Reset the read_data_* variables, used for starting a new entry.
897 */
__archive_reset_read_data(struct archive * a)898 void __archive_reset_read_data(struct archive * a)
899 {
900 a->read_data_output_offset = 0;
901 a->read_data_remaining = 0;
902 a->read_data_is_posix_read = 0;
903 a->read_data_requested = 0;
904
905 /* extra resets, from rar.c */
906 a->read_data_block = NULL;
907 a->read_data_offset = 0;
908 }
909
910 /*
911 * Skip over all remaining data in this entry.
912 */
913 int
archive_read_data_skip(struct archive * _a)914 archive_read_data_skip(struct archive *_a)
915 {
916 struct archive_read *a = (struct archive_read *)_a;
917 int r;
918 const void *buff;
919 size_t size;
920 int64_t offset;
921
922 archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_DATA,
923 "archive_read_data_skip");
924
925 if (a->format->read_data_skip != NULL)
926 r = (a->format->read_data_skip)(a);
927 else {
928 while ((r = archive_read_data_block(&a->archive,
929 &buff, &size, &offset))
930 == ARCHIVE_OK)
931 ;
932 }
933
934 if (r == ARCHIVE_EOF)
935 r = ARCHIVE_OK;
936
937 a->archive.state = ARCHIVE_STATE_HEADER;
938 return (r);
939 }
940
941 la_int64_t
archive_seek_data(struct archive * _a,int64_t offset,int whence)942 archive_seek_data(struct archive *_a, int64_t offset, int whence)
943 {
944 struct archive_read *a = (struct archive_read *)_a;
945 archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_DATA,
946 "archive_seek_data_block");
947
948 if (a->format->seek_data == NULL) {
949 archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER,
950 "Internal error: "
951 "No format_seek_data_block function registered");
952 return (ARCHIVE_FATAL);
953 }
954
955 return (a->format->seek_data)(a, offset, whence);
956 }
957
958 /*
959 * Read the next block of entry data from the archive.
960 * This is a zero-copy interface; the client receives a pointer,
961 * size, and file offset of the next available block of data.
962 *
963 * Returns ARCHIVE_OK if the operation is successful, ARCHIVE_EOF if
964 * the end of entry is encountered.
965 */
966 static int
_archive_read_data_block(struct archive * _a,const void ** buff,size_t * size,int64_t * offset)967 _archive_read_data_block(struct archive *_a,
968 const void **buff, size_t *size, int64_t *offset)
969 {
970 struct archive_read *a = (struct archive_read *)_a;
971 archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_DATA,
972 "archive_read_data_block");
973
974 if (a->format->read_data == NULL) {
975 archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER,
976 "Internal error: "
977 "No format->read_data function registered");
978 return (ARCHIVE_FATAL);
979 }
980
981 return (a->format->read_data)(a, buff, size, offset);
982 }
983
984 static int
close_filters(struct archive_read * a)985 close_filters(struct archive_read *a)
986 {
987 struct archive_read_filter *f = a->filter;
988 int r = ARCHIVE_OK;
989 /* Close each filter in the pipeline. */
990 while (f != NULL) {
991 struct archive_read_filter *t = f->upstream;
992 if (!f->closed && f->vtable != NULL) {
993 int r1 = (f->vtable->close)(f);
994 f->closed = 1;
995 if (r1 < r)
996 r = r1;
997 }
998 free(f->buffer);
999 f->buffer = NULL;
1000 f = t;
1001 }
1002 return r;
1003 }
1004
1005 void
__archive_read_free_filters(struct archive_read * a)1006 __archive_read_free_filters(struct archive_read *a)
1007 {
1008 /* Make sure filters are closed and their buffers are freed */
1009 close_filters(a);
1010
1011 while (a->filter != NULL) {
1012 struct archive_read_filter *t = a->filter->upstream;
1013 free(a->filter);
1014 a->filter = t;
1015 }
1016 }
1017
1018 /*
1019 * return the count of # of filters in use
1020 */
1021 static int
_archive_filter_count(struct archive * _a)1022 _archive_filter_count(struct archive *_a)
1023 {
1024 struct archive_read *a = (struct archive_read *)_a;
1025 struct archive_read_filter *p = a->filter;
1026 int count = 0;
1027 while(p) {
1028 count++;
1029 p = p->upstream;
1030 }
1031 return count;
1032 }
1033
1034 /*
1035 * Close the file and all I/O.
1036 */
1037 static int
_archive_read_close(struct archive * _a)1038 _archive_read_close(struct archive *_a)
1039 {
1040 struct archive_read *a = (struct archive_read *)_a;
1041 int r = ARCHIVE_OK, r1 = ARCHIVE_OK;
1042
1043 archive_check_magic(&a->archive, ARCHIVE_READ_MAGIC,
1044 ARCHIVE_STATE_ANY | ARCHIVE_STATE_FATAL, "archive_read_close");
1045 if (a->archive.state == ARCHIVE_STATE_CLOSED)
1046 return (ARCHIVE_OK);
1047 archive_clear_error(&a->archive);
1048 a->archive.state = ARCHIVE_STATE_CLOSED;
1049
1050 /* TODO: Clean up the formatters. */
1051
1052 /* Release the filter objects. */
1053 r1 = close_filters(a);
1054 if (r1 < r)
1055 r = r1;
1056
1057 return (r);
1058 }
1059
1060 /*
1061 * Release memory and other resources.
1062 */
1063 static int
_archive_read_free(struct archive * _a)1064 _archive_read_free(struct archive *_a)
1065 {
1066 struct archive_read *a = (struct archive_read *)_a;
1067 struct archive_read_passphrase *p;
1068 int i, n;
1069 int slots;
1070 int r = ARCHIVE_OK;
1071
1072 if (_a == NULL)
1073 return (ARCHIVE_OK);
1074 archive_check_magic(_a, ARCHIVE_READ_MAGIC,
1075 ARCHIVE_STATE_ANY | ARCHIVE_STATE_FATAL, "archive_read_free");
1076 if (a->archive.state != ARCHIVE_STATE_CLOSED
1077 && a->archive.state != ARCHIVE_STATE_FATAL)
1078 r = archive_read_close(&a->archive);
1079
1080 /* Call cleanup functions registered by optional components. */
1081 if (a->cleanup_archive_extract != NULL)
1082 r = (a->cleanup_archive_extract)(a);
1083
1084 /* Cleanup format-specific data. */
1085 slots = sizeof(a->formats) / sizeof(a->formats[0]);
1086 for (i = 0; i < slots; i++) {
1087 a->format = &(a->formats[i]);
1088 if (a->formats[i].cleanup)
1089 (a->formats[i].cleanup)(a);
1090 }
1091
1092 /* Free the filters */
1093 __archive_read_free_filters(a);
1094
1095 /* Release the bidder objects. */
1096 n = sizeof(a->bidders)/sizeof(a->bidders[0]);
1097 for (i = 0; i < n; i++) {
1098 if (a->bidders[i].vtable == NULL ||
1099 a->bidders[i].vtable->free == NULL)
1100 continue;
1101 (a->bidders[i].vtable->free)(&a->bidders[i]);
1102 }
1103
1104 /* Release passphrase list. */
1105 p = a->passphrases.first;
1106 while (p != NULL) {
1107 struct archive_read_passphrase *np = p->next;
1108
1109 /* A passphrase should be cleaned. */
1110 memset(p->passphrase, 0, strlen(p->passphrase));
1111 free(p->passphrase);
1112 free(p);
1113 p = np;
1114 }
1115
1116 archive_string_free(&a->archive.error_string);
1117 archive_entry_free(a->entry);
1118 a->archive.magic = 0;
1119 __archive_clean(&a->archive);
1120 free(a->client.dataset);
1121 free(a);
1122 return (r);
1123 }
1124
1125 static struct archive_read_filter *
get_filter(struct archive * _a,int n)1126 get_filter(struct archive *_a, int n)
1127 {
1128 struct archive_read *a = (struct archive_read *)_a;
1129 struct archive_read_filter *f = a->filter;
1130 /* We use n == -1 for 'the last filter', which is always the
1131 * client proxy. */
1132 if (n == -1 && f != NULL) {
1133 struct archive_read_filter *last = f;
1134 f = f->upstream;
1135 while (f != NULL) {
1136 last = f;
1137 f = f->upstream;
1138 }
1139 return (last);
1140 }
1141 if (n < 0)
1142 return NULL;
1143 while (n > 0 && f != NULL) {
1144 f = f->upstream;
1145 --n;
1146 }
1147 return (f);
1148 }
1149
1150 static int
_archive_filter_code(struct archive * _a,int n)1151 _archive_filter_code(struct archive *_a, int n)
1152 {
1153 struct archive_read_filter *f = get_filter(_a, n);
1154 return f == NULL ? -1 : f->code;
1155 }
1156
1157 static const char *
_archive_filter_name(struct archive * _a,int n)1158 _archive_filter_name(struct archive *_a, int n)
1159 {
1160 struct archive_read_filter *f = get_filter(_a, n);
1161 return f != NULL ? f->name : NULL;
1162 }
1163
1164 static int64_t
_archive_filter_bytes(struct archive * _a,int n)1165 _archive_filter_bytes(struct archive *_a, int n)
1166 {
1167 struct archive_read_filter *f = get_filter(_a, n);
1168 return f == NULL ? -1 : f->position;
1169 }
1170
1171 /*
1172 * Used internally by read format handlers to register their bid and
1173 * initialization functions.
1174 */
1175 int
__archive_read_register_format(struct archive_read * a,void * format_data,const char * name,int (* bid)(struct archive_read *,int),int (* options)(struct archive_read *,const char *,const char *),int (* read_header)(struct archive_read *,struct archive_entry *),int (* read_data)(struct archive_read *,const void **,size_t *,int64_t *),int (* read_data_skip)(struct archive_read *),int64_t (* seek_data)(struct archive_read *,int64_t,int),int (* cleanup)(struct archive_read *),int (* format_capabilities)(struct archive_read *),int (* has_encrypted_entries)(struct archive_read *))1176 __archive_read_register_format(struct archive_read *a,
1177 void *format_data,
1178 const char *name,
1179 int (*bid)(struct archive_read *, int),
1180 int (*options)(struct archive_read *, const char *, const char *),
1181 int (*read_header)(struct archive_read *, struct archive_entry *),
1182 int (*read_data)(struct archive_read *, const void **, size_t *, int64_t *),
1183 int (*read_data_skip)(struct archive_read *),
1184 int64_t (*seek_data)(struct archive_read *, int64_t, int),
1185 int (*cleanup)(struct archive_read *),
1186 int (*format_capabilities)(struct archive_read *),
1187 int (*has_encrypted_entries)(struct archive_read *))
1188 {
1189 int i, number_slots;
1190
1191 archive_check_magic(&a->archive,
1192 ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
1193 "__archive_read_register_format");
1194
1195 number_slots = sizeof(a->formats) / sizeof(a->formats[0]);
1196
1197 for (i = 0; i < number_slots; i++) {
1198 if (a->formats[i].bid == bid)
1199 return (ARCHIVE_WARN); /* We've already installed */
1200 if (a->formats[i].bid == NULL) {
1201 a->formats[i].bid = bid;
1202 a->formats[i].options = options;
1203 a->formats[i].read_header = read_header;
1204 a->formats[i].read_data = read_data;
1205 a->formats[i].read_data_skip = read_data_skip;
1206 a->formats[i].seek_data = seek_data;
1207 a->formats[i].cleanup = cleanup;
1208 a->formats[i].data = format_data;
1209 a->formats[i].name = name;
1210 a->formats[i].format_capabilties = format_capabilities;
1211 a->formats[i].has_encrypted_entries = has_encrypted_entries;
1212 return (ARCHIVE_OK);
1213 }
1214 }
1215
1216 archive_set_error(&a->archive, ENOMEM,
1217 "Not enough slots for format registration");
1218 return (ARCHIVE_FATAL);
1219 }
1220
1221 /*
1222 * Used internally by decompression routines to register their bid and
1223 * initialization functions.
1224 */
1225 int
__archive_read_register_bidder(struct archive_read * a,void * bidder_data,const char * name,const struct archive_read_filter_bidder_vtable * vtable)1226 __archive_read_register_bidder(struct archive_read *a,
1227 void *bidder_data,
1228 const char *name,
1229 const struct archive_read_filter_bidder_vtable *vtable)
1230 {
1231 struct archive_read_filter_bidder *bidder;
1232 int i, number_slots;
1233
1234 archive_check_magic(&a->archive, ARCHIVE_READ_MAGIC,
1235 ARCHIVE_STATE_NEW, "__archive_read_register_bidder");
1236
1237 number_slots = sizeof(a->bidders) / sizeof(a->bidders[0]);
1238
1239 for (i = 0; i < number_slots; i++) {
1240 if (a->bidders[i].vtable != NULL)
1241 continue;
1242 memset(a->bidders + i, 0, sizeof(a->bidders[0]));
1243 bidder = (a->bidders + i);
1244 bidder->data = bidder_data;
1245 bidder->name = name;
1246 bidder->vtable = vtable;
1247 if (bidder->vtable->bid == NULL || bidder->vtable->init == NULL) {
1248 archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER,
1249 "Internal error: "
1250 "no bid/init for filter bidder");
1251 return (ARCHIVE_FATAL);
1252 }
1253
1254 return (ARCHIVE_OK);
1255 }
1256
1257 archive_set_error(&a->archive, ENOMEM,
1258 "Not enough slots for filter registration");
1259 return (ARCHIVE_FATAL);
1260 }
1261
1262 /*
1263 * The next section implements the peek/consume internal I/O
1264 * system used by archive readers. This system allows simple
1265 * read-ahead for consumers while preserving zero-copy operation
1266 * most of the time.
1267 *
1268 * The two key operations:
1269 * * The read-ahead function returns a pointer to a block of data
1270 * that satisfies a minimum request.
1271 * * The consume function advances the file pointer.
1272 *
1273 * In the ideal case, filters generate blocks of data
1274 * and __archive_read_ahead() just returns pointers directly into
1275 * those blocks. Then __archive_read_consume() just bumps those
1276 * pointers. Only if your request would span blocks does the I/O
1277 * layer use a copy buffer to provide you with a contiguous block of
1278 * data.
1279 *
1280 * A couple of useful idioms:
1281 * * "I just want some data." Ask for 1 byte and pay attention to
1282 * the "number of bytes available" from __archive_read_ahead().
1283 * Consume whatever you actually use.
1284 * * "I want to output a large block of data." As above, ask for 1 byte,
1285 * emit all that's available (up to whatever limit you have), consume
1286 * it all, then repeat until you're done. This effectively means that
1287 * you're passing along the blocks that came from your provider.
1288 * * "I want to peek ahead by a large amount." Ask for 4k or so, then
1289 * double and repeat until you get an error or have enough. Note
1290 * that the I/O layer will likely end up expanding its copy buffer
1291 * to fit your request, so use this technique cautiously. This
1292 * technique is used, for example, by some of the format tasting
1293 * code that has uncertain look-ahead needs.
1294 */
1295
1296 /*
1297 * Looks ahead in the input stream:
1298 * * If 'avail' pointer is provided, that returns number of bytes available
1299 * in the current buffer, which may be much larger than requested.
1300 * * If end-of-file, *avail gets set to zero.
1301 * * If error, *avail gets error code.
1302 * * If request can be met, returns pointer to data.
1303 * * If minimum request cannot be met, returns NULL.
1304 *
1305 * Note: If you just want "some data", ask for 1 byte and pay attention
1306 * to *avail, which will have the actual amount available. If you
1307 * know exactly how many bytes you need, just ask for that and treat
1308 * a NULL return as an error.
1309 *
1310 * Important: This does NOT move the file pointer. See
1311 * __archive_read_consume() below.
1312 */
1313 const void *
__archive_read_ahead(struct archive_read * a,size_t min,ssize_t * avail)1314 __archive_read_ahead(struct archive_read *a, size_t min, ssize_t *avail)
1315 {
1316 return (__archive_read_filter_ahead(a->filter, min, avail));
1317 }
1318
1319 const void *
__archive_read_filter_ahead(struct archive_read_filter * filter,size_t min,ssize_t * avail)1320 __archive_read_filter_ahead(struct archive_read_filter *filter,
1321 size_t min, ssize_t *avail)
1322 {
1323 ssize_t bytes_read;
1324 size_t tocopy;
1325
1326 if (filter->fatal) {
1327 if (avail)
1328 *avail = ARCHIVE_FATAL;
1329 return (NULL);
1330 }
1331
1332 /*
1333 * Keep pulling more data until we can satisfy the request.
1334 */
1335 for (;;) {
1336
1337 /*
1338 * If we can satisfy from the copy buffer (and the
1339 * copy buffer isn't empty), we're done. In particular,
1340 * note that min == 0 is a perfectly well-defined
1341 * request.
1342 */
1343 if (filter->avail >= min && filter->avail > 0) {
1344 if (avail != NULL)
1345 *avail = filter->avail;
1346 return (filter->next);
1347 }
1348
1349 /*
1350 * We can satisfy directly from client buffer if everything
1351 * currently in the copy buffer is still in the client buffer.
1352 */
1353 if (filter->client_total >= filter->client_avail + filter->avail
1354 && filter->client_avail + filter->avail >= min) {
1355 /* "Roll back" to client buffer. */
1356 filter->client_avail += filter->avail;
1357 filter->client_next -= filter->avail;
1358 /* Copy buffer is now empty. */
1359 filter->avail = 0;
1360 filter->next = filter->buffer;
1361 /* Return data from client buffer. */
1362 if (avail != NULL)
1363 *avail = filter->client_avail;
1364 return (filter->client_next);
1365 }
1366
1367 /* Move data forward in copy buffer if necessary. */
1368 if (filter->next > filter->buffer &&
1369 filter->next + min > filter->buffer + filter->buffer_size) {
1370 if (filter->avail > 0)
1371 memmove(filter->buffer, filter->next,
1372 filter->avail);
1373 filter->next = filter->buffer;
1374 }
1375
1376 /* If we've used up the client data, get more. */
1377 if (filter->client_avail <= 0) {
1378 if (filter->end_of_file) {
1379 if (avail != NULL)
1380 *avail = filter->avail;
1381 return (NULL);
1382 }
1383 bytes_read = (filter->vtable->read)(filter,
1384 &filter->client_buff);
1385 if (bytes_read < 0) { /* Read error. */
1386 filter->client_total = filter->client_avail = 0;
1387 filter->client_next =
1388 filter->client_buff = NULL;
1389 filter->fatal = 1;
1390 if (avail != NULL)
1391 *avail = ARCHIVE_FATAL;
1392 return (NULL);
1393 }
1394 if (bytes_read == 0) {
1395 /* Check for another client object first */
1396 if (filter->archive->client.cursor !=
1397 filter->archive->client.nodes - 1) {
1398 if (client_switch_proxy(filter,
1399 filter->archive->client.cursor + 1)
1400 == ARCHIVE_OK)
1401 continue;
1402 }
1403 /* Premature end-of-file. */
1404 filter->client_total = filter->client_avail = 0;
1405 filter->client_next =
1406 filter->client_buff = NULL;
1407 filter->end_of_file = 1;
1408 /* Return whatever we do have. */
1409 if (avail != NULL)
1410 *avail = filter->avail;
1411 return (NULL);
1412 }
1413 filter->client_total = bytes_read;
1414 filter->client_avail = filter->client_total;
1415 filter->client_next = filter->client_buff;
1416 } else {
1417 /*
1418 * We can't satisfy the request from the copy
1419 * buffer or the existing client data, so we
1420 * need to copy more client data over to the
1421 * copy buffer.
1422 */
1423
1424 /* Ensure the buffer is big enough. */
1425 if (min > filter->buffer_size) {
1426 size_t s, t;
1427 char *p;
1428
1429 /* Double the buffer; watch for overflow. */
1430 s = t = filter->buffer_size;
1431 if (s == 0)
1432 s = min;
1433 while (s < min) {
1434 t *= 2;
1435 if (t <= s) { /* Integer overflow! */
1436 archive_set_error(
1437 &filter->archive->archive,
1438 ENOMEM,
1439 "Unable to allocate copy"
1440 " buffer");
1441 filter->fatal = 1;
1442 if (avail != NULL)
1443 *avail = ARCHIVE_FATAL;
1444 return (NULL);
1445 }
1446 s = t;
1447 }
1448 /* Now s >= min, so allocate a new buffer. */
1449 p = malloc(s);
1450 if (p == NULL) {
1451 archive_set_error(
1452 &filter->archive->archive,
1453 ENOMEM,
1454 "Unable to allocate copy buffer");
1455 filter->fatal = 1;
1456 if (avail != NULL)
1457 *avail = ARCHIVE_FATAL;
1458 return (NULL);
1459 }
1460 /* Move data into newly-enlarged buffer. */
1461 if (filter->avail > 0)
1462 memmove(p, filter->next, filter->avail);
1463 free(filter->buffer);
1464 filter->next = filter->buffer = p;
1465 filter->buffer_size = s;
1466 }
1467
1468 /* We can add client data to copy buffer. */
1469 /* First estimate: copy to fill rest of buffer. */
1470 tocopy = (filter->buffer + filter->buffer_size)
1471 - (filter->next + filter->avail);
1472 /* Don't waste time buffering more than we need to. */
1473 if (tocopy + filter->avail > min)
1474 tocopy = min - filter->avail;
1475 /* Don't copy more than is available. */
1476 if (tocopy > filter->client_avail)
1477 tocopy = filter->client_avail;
1478
1479 memcpy(filter->next + filter->avail,
1480 filter->client_next, tocopy);
1481 /* Remove this data from client buffer. */
1482 filter->client_next += tocopy;
1483 filter->client_avail -= tocopy;
1484 /* add it to copy buffer. */
1485 filter->avail += tocopy;
1486 }
1487 }
1488 }
1489
1490 /*
1491 * Move the file pointer forward.
1492 */
1493 int64_t
__archive_read_consume(struct archive_read * a,int64_t request)1494 __archive_read_consume(struct archive_read *a, int64_t request)
1495 {
1496 return (__archive_read_filter_consume(a->filter, request));
1497 }
1498
1499 int64_t
__archive_read_filter_consume(struct archive_read_filter * filter,int64_t request)1500 __archive_read_filter_consume(struct archive_read_filter * filter,
1501 int64_t request)
1502 {
1503 int64_t skipped;
1504
1505 if (request < 0)
1506 return ARCHIVE_FATAL;
1507 if (request == 0)
1508 return 0;
1509
1510 skipped = advance_file_pointer(filter, request);
1511 if (skipped == request)
1512 return (skipped);
1513 /* We hit EOF before we satisfied the skip request. */
1514 if (skipped < 0) /* Map error code to 0 for error message below. */
1515 skipped = 0;
1516 archive_set_error(&filter->archive->archive,
1517 ARCHIVE_ERRNO_MISC,
1518 "Truncated input file (needed %jd bytes, only %jd available)",
1519 (intmax_t)request, (intmax_t)skipped);
1520 return (ARCHIVE_FATAL);
1521 }
1522
1523 /*
1524 * Advance the file pointer by the amount requested.
1525 * Returns the amount actually advanced, which may be less than the
1526 * request if EOF is encountered first.
1527 * Returns a negative value if there's an I/O error.
1528 */
1529 static int64_t
advance_file_pointer(struct archive_read_filter * filter,int64_t request)1530 advance_file_pointer(struct archive_read_filter *filter, int64_t request)
1531 {
1532 int64_t bytes_skipped, total_bytes_skipped = 0;
1533 ssize_t bytes_read;
1534 size_t min;
1535
1536 if (filter->fatal)
1537 return (-1);
1538
1539 /* Use up the copy buffer first. */
1540 if (filter->avail > 0) {
1541 min = (size_t)minimum(request, (int64_t)filter->avail);
1542 filter->next += min;
1543 filter->avail -= min;
1544 request -= min;
1545 filter->position += min;
1546 total_bytes_skipped += min;
1547 }
1548
1549 /* Then use up the client buffer. */
1550 if (filter->client_avail > 0) {
1551 min = (size_t)minimum(request, (int64_t)filter->client_avail);
1552 filter->client_next += min;
1553 filter->client_avail -= min;
1554 request -= min;
1555 filter->position += min;
1556 total_bytes_skipped += min;
1557 }
1558 if (request == 0)
1559 return (total_bytes_skipped);
1560
1561 /* If there's an optimized skip function, use it. */
1562 if (filter->can_skip != 0) {
1563 bytes_skipped = client_skip_proxy(filter, request);
1564 if (bytes_skipped < 0) { /* error */
1565 filter->fatal = 1;
1566 return (bytes_skipped);
1567 }
1568 filter->position += bytes_skipped;
1569 total_bytes_skipped += bytes_skipped;
1570 request -= bytes_skipped;
1571 if (request == 0)
1572 return (total_bytes_skipped);
1573 }
1574
1575 /* Use ordinary reads as necessary to complete the request. */
1576 for (;;) {
1577 bytes_read = (filter->vtable->read)(filter, &filter->client_buff);
1578 if (bytes_read < 0) {
1579 filter->client_buff = NULL;
1580 filter->fatal = 1;
1581 return (bytes_read);
1582 }
1583
1584 if (bytes_read == 0) {
1585 if (filter->archive->client.cursor !=
1586 filter->archive->client.nodes - 1) {
1587 if (client_switch_proxy(filter,
1588 filter->archive->client.cursor + 1)
1589 == ARCHIVE_OK)
1590 continue;
1591 }
1592 filter->client_buff = NULL;
1593 filter->end_of_file = 1;
1594 return (total_bytes_skipped);
1595 }
1596
1597 if (bytes_read >= request) {
1598 filter->client_next =
1599 ((const char *)filter->client_buff) + request;
1600 filter->client_avail = (size_t)(bytes_read - request);
1601 filter->client_total = bytes_read;
1602 total_bytes_skipped += request;
1603 filter->position += request;
1604 return (total_bytes_skipped);
1605 }
1606
1607 filter->position += bytes_read;
1608 total_bytes_skipped += bytes_read;
1609 request -= bytes_read;
1610 }
1611 }
1612
1613 /**
1614 * Returns ARCHIVE_FAILED if seeking isn't supported.
1615 */
1616 int64_t
__archive_read_seek(struct archive_read * a,int64_t offset,int whence)1617 __archive_read_seek(struct archive_read *a, int64_t offset, int whence)
1618 {
1619 return __archive_read_filter_seek(a->filter, offset, whence);
1620 }
1621
1622 int64_t
__archive_read_filter_seek(struct archive_read_filter * filter,int64_t offset,int whence)1623 __archive_read_filter_seek(struct archive_read_filter *filter, int64_t offset,
1624 int whence)
1625 {
1626 struct archive_read_client *client;
1627 int64_t r;
1628 unsigned int cursor;
1629
1630 if (filter->closed || filter->fatal)
1631 return (ARCHIVE_FATAL);
1632 if (filter->can_seek == 0)
1633 return (ARCHIVE_FAILED);
1634
1635 client = &(filter->archive->client);
1636 switch (whence) {
1637 case SEEK_CUR:
1638 /* Adjust the offset and use SEEK_SET instead */
1639 offset += filter->position;
1640 __LA_FALLTHROUGH;
1641 case SEEK_SET:
1642 cursor = 0;
1643 while (1)
1644 {
1645 if (client->dataset[cursor].begin_position < 0 ||
1646 client->dataset[cursor].total_size < 0 ||
1647 client->dataset[cursor].begin_position +
1648 client->dataset[cursor].total_size - 1 > offset ||
1649 cursor + 1 >= client->nodes)
1650 break;
1651 r = client->dataset[cursor].begin_position +
1652 client->dataset[cursor].total_size;
1653 client->dataset[++cursor].begin_position = r;
1654 }
1655 while (1) {
1656 r = client_switch_proxy(filter, cursor);
1657 if (r != ARCHIVE_OK)
1658 return r;
1659 if ((r = client_seek_proxy(filter, 0, SEEK_END)) < 0)
1660 return r;
1661 client->dataset[cursor].total_size = r;
1662 if (client->dataset[cursor].begin_position +
1663 client->dataset[cursor].total_size - 1 > offset ||
1664 cursor + 1 >= client->nodes)
1665 break;
1666 r = client->dataset[cursor].begin_position +
1667 client->dataset[cursor].total_size;
1668 client->dataset[++cursor].begin_position = r;
1669 }
1670 offset -= client->dataset[cursor].begin_position;
1671 if (offset < 0
1672 || offset > client->dataset[cursor].total_size)
1673 return ARCHIVE_FATAL;
1674 if ((r = client_seek_proxy(filter, offset, SEEK_SET)) < 0)
1675 return r;
1676 break;
1677
1678 case SEEK_END:
1679 cursor = 0;
1680 while (1) {
1681 if (client->dataset[cursor].begin_position < 0 ||
1682 client->dataset[cursor].total_size < 0 ||
1683 cursor + 1 >= client->nodes)
1684 break;
1685 r = client->dataset[cursor].begin_position +
1686 client->dataset[cursor].total_size;
1687 client->dataset[++cursor].begin_position = r;
1688 }
1689 while (1) {
1690 r = client_switch_proxy(filter, cursor);
1691 if (r != ARCHIVE_OK)
1692 return r;
1693 if ((r = client_seek_proxy(filter, 0, SEEK_END)) < 0)
1694 return r;
1695 client->dataset[cursor].total_size = r;
1696 r = client->dataset[cursor].begin_position +
1697 client->dataset[cursor].total_size;
1698 if (cursor + 1 >= client->nodes)
1699 break;
1700 client->dataset[++cursor].begin_position = r;
1701 }
1702 while (1) {
1703 if (r + offset >=
1704 client->dataset[cursor].begin_position)
1705 break;
1706 offset += client->dataset[cursor].total_size;
1707 if (cursor == 0)
1708 break;
1709 cursor--;
1710 r = client->dataset[cursor].begin_position +
1711 client->dataset[cursor].total_size;
1712 }
1713 offset = (r + offset) - client->dataset[cursor].begin_position;
1714 if ((r = client_switch_proxy(filter, cursor)) != ARCHIVE_OK)
1715 return r;
1716 r = client_seek_proxy(filter, offset, SEEK_SET);
1717 if (r < ARCHIVE_OK)
1718 return r;
1719 break;
1720
1721 default:
1722 return (ARCHIVE_FATAL);
1723 }
1724 r += client->dataset[cursor].begin_position;
1725
1726 if (r >= 0) {
1727 /*
1728 * Ouch. Clearing the buffer like this hurts, especially
1729 * at bid time. A lot of our efficiency at bid time comes
1730 * from having bidders reuse the data we've already read.
1731 *
1732 * TODO: If the seek request is in data we already
1733 * have, then don't call the seek callback.
1734 *
1735 * TODO: Zip seeks to end-of-file at bid time. If
1736 * other formats also start doing this, we may need to
1737 * find a way for clients to fudge the seek offset to
1738 * a block boundary.
1739 *
1740 * Hmmm... If whence was SEEK_END, we know the file
1741 * size is (r - offset). Can we use that to simplify
1742 * the TODO items above?
1743 */
1744 filter->avail = filter->client_avail = 0;
1745 filter->next = filter->buffer;
1746 filter->position = r;
1747 filter->end_of_file = 0;
1748 }
1749 return r;
1750 }
1751