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Date:: Sat Mar 30 17:17:56 2024 UTC
Message:: add support for reading blobs to object_open_io.c
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1 /*
2  * Copyright (c) 2022 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include "got_compat.h"
18 
19 #include <sys/queue.h>
20 #include <sys/stat.h>
21 
22 #include <errno.h>
23 #include <limits.h>
24 #include <stdio.h>
25 #include <stdlib.h>
26 #include <string.h>
27 #include <unistd.h>
28 #include <zlib.h>
29 
30 #include "got_error.h"
31 #include "got_object.h"
32 #include "got_repository.h"
33 #include "got_path.h"
34 
35 #include "got_lib_delta.h"
36 #include "got_lib_object.h"
37 #include "got_lib_object_cache.h"
38 #include "got_lib_object_parse.h"
39 #include "got_lib_pack.h"
40 #include "got_lib_repository.h"
41 #include "got_lib_inflate.h"
42 #include "got_lib_hash.h"
43 
44 const struct got_error *
45 got_object_open_packed(struct got_object **obj, struct got_object_id *id,
46     struct got_repository *repo)
47 {
48 	const struct got_error *err = NULL;
49 	struct got_pack *pack = NULL;
50 	struct got_packidx *packidx = NULL;
51 	int idx;
52 	char *path_packfile;
53 
54 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
55 	if (err)
56 		return err;
57 
58 	err = got_packidx_get_packfile_path(&path_packfile,
59 	    packidx->path_packidx);
60 	if (err)
61 		return err;
62 
63 	pack = got_repo_get_cached_pack(repo, path_packfile);
64 	if (pack == NULL) {
65 		err = got_repo_cache_pack(&pack, repo, path_packfile, packidx);
66 		if (err)
67 			goto done;
68 	}
69 
70 	err = got_packfile_open_object(obj, pack, packidx, idx, id);
71 	if (err)
72 		return err;
73 	(*obj)->refcnt++;
74 
75 	err = got_repo_cache_object(repo, id, *obj);
76 	if (err) {
77 		if (err->code == GOT_ERR_OBJ_EXISTS ||
78 		    err->code == GOT_ERR_OBJ_TOO_LARGE)
79 			err = NULL;
80 	}
81 done:
82 	free(path_packfile);
83 	return err;
84 }
85 
86 const struct got_error *
87 got_object_open_from_packfile(struct got_object **obj, struct got_object_id *id,
88     struct got_pack *pack, struct got_packidx *packidx, int obj_idx,
89     struct got_repository *repo)
90 {
91 	const struct got_error *err;
92 
93 	*obj = got_repo_get_cached_object(repo, id);
94 	if (*obj != NULL) {
95 		(*obj)->refcnt++;
96 		return NULL;
97 	}
98 
99 	err = got_packfile_open_object(obj, pack, packidx, obj_idx, id);
100 	if (err)
101 		return err;
102 	(*obj)->refcnt++;
103 
104 	err = got_repo_cache_object(repo, id, *obj);
105 	if (err) {
106 		if (err->code == GOT_ERR_OBJ_EXISTS ||
107 		    err->code == GOT_ERR_OBJ_TOO_LARGE)
108 			err = NULL;
109 		return err;
110 	}
111 	(*obj)->refcnt++;
112 	return NULL;
113 }
114 
115 const struct got_error *
116 got_object_read_raw_delta(uint64_t *base_size, uint64_t *result_size,
117     off_t *delta_size, off_t *delta_compressed_size, off_t *delta_offset,
118     off_t *delta_out_offset, struct got_object_id **base_id, int delta_cache_fd,
119     struct got_packidx *packidx, int obj_idx, struct got_object_id *id,
120     struct got_repository *repo)
121 {
122 	return got_error(GOT_ERR_NOT_IMPL);
123 }
124 
125 const struct got_error *
126 got_object_open(struct got_object **obj, struct got_repository *repo,
127     struct got_object_id *id)
128 {
129 	const struct got_error *err = NULL;
130 	int fd;
131 
132 	*obj = got_repo_get_cached_object(repo, id);
133 	if (*obj != NULL) {
134 		(*obj)->refcnt++;
135 		return NULL;
136 	}
137 
138 	err = got_object_open_packed(obj, id, repo);
139 	if (err) {
140 		if (err->code != GOT_ERR_NO_OBJ)
141 			return err;
142 	} else
143 		return NULL;
144 
145 	err = got_object_open_loose_fd(&fd, id, repo);
146 	if (err) {
147 		if (err->code == GOT_ERR_ERRNO && errno == ENOENT)
148 			err = got_error_no_obj(id);
149 		return err;
150 	}
151 
152 	err = got_object_read_header(obj, fd);
153 	if (err)
154 		goto done;
155 
156 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
157 	(*obj)->refcnt++;
158 
159 	err = got_repo_cache_object(repo, id, *obj);
160 	if (err) {
161 		if (err->code == GOT_ERR_OBJ_EXISTS ||
162 		    err->code == GOT_ERR_OBJ_TOO_LARGE)
163 			err = NULL;
164 	}
165 done:
166 	if (close(fd) == -1 && err == NULL)
167 		err = got_error_from_errno("close");
168 	return err;
169 }
170 
171 static const struct got_error *
172 wrap_fd(FILE **f, int wrapped_fd)
173 {
174 	const struct got_error *err = NULL;
175 	int fd;
176 
177 	if (ftruncate(wrapped_fd, 0L) == -1)
178 		return got_error_from_errno("ftruncate");
179 
180 	if (lseek(wrapped_fd, 0L, SEEK_SET) == -1)
181 		return got_error_from_errno("lseek");
182 
183 	fd = dup(wrapped_fd);
184 	if (fd == -1)
185 		return got_error_from_errno("dup");
186 
187 	*f = fdopen(fd, "w+");
188 	if (*f == NULL) {
189 		err = got_error_from_errno("fdopen");
190 		close(fd);
191 	}
192 	return err;
193 }
194 
195 static const struct got_error *
196 read_packed_object_raw(uint8_t **outbuf, off_t *size, size_t *hdrlen,
197     int outfd, struct got_pack *pack, struct got_packidx *packidx, int idx,
198     struct got_object_id *id)
199 {
200 	const struct got_error *err = NULL;
201 	uint64_t raw_size = 0;
202 	struct got_object *obj;
203 	FILE *outfile = NULL, *basefile = NULL, *accumfile = NULL;
204 
205 	*outbuf = NULL;
206 	*size = 0;
207 	*hdrlen = 0;
208 
209 	err = got_packfile_open_object(&obj, pack, packidx, idx, id);
210 	if (err)
211 		return err;
212 
213 	if (obj->flags & GOT_OBJ_FLAG_DELTIFIED) {
214 		err = got_pack_get_max_delta_object_size(&raw_size, obj, pack);
215 		if (err)
216 			goto done;
217 	} else
218 		raw_size = obj->size;
219 
220 	if (raw_size <= GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
221 		size_t len;
222 		err = got_packfile_extract_object_to_mem(outbuf, &len,
223 		    obj, pack);
224 		if (err)
225 			goto done;
226 		*size = (off_t)len;
227 	} else {
228 		/*
229 		 * XXX This uses 3 file extra descriptors for no good reason.
230 		 * We should have got_packfile_extract_object_to_fd().
231 		 */
232 		err = wrap_fd(&outfile, outfd);
233 		if (err)
234 			goto done;
235 		err = wrap_fd(&basefile, pack->basefd);
236 		if (err)
237 			goto done;
238 		err = wrap_fd(&accumfile, pack->accumfd);
239 		if (err)
240 			goto done;
241 		err = got_packfile_extract_object(pack, obj, outfile, basefile,
242 		    accumfile);
243 		if (err)
244 			goto done;
245 		*size = obj->size;
246 	}
247 
248 	*hdrlen = obj->hdrlen;
249 done:
250 	got_object_close(obj);
251 	if (outfile && fclose(outfile) == EOF && err == NULL)
252 		err = got_error_from_errno("fclose");
253 	if (basefile && fclose(basefile) == EOF && err == NULL)
254 		err = got_error_from_errno("fclose");
255 	if (accumfile && fclose(accumfile) == EOF && err == NULL)
256 		err = got_error_from_errno("fclose");
257 	return err;
258 
259 }
260 
261 static void
262 put_raw_object_tempfile(struct got_raw_object *obj)
263 {
264 	struct got_repository *repo = obj->close_arg;
265 
266 	if (obj->tempfile_idx != -1)
267 		got_repo_temp_fds_put(obj->tempfile_idx, repo);
268 }
269 
270 /* *outfd must be initialized to -1 by caller */
271 const struct got_error *
272 got_object_raw_open(struct got_raw_object **obj, int *outfd,
273     struct got_repository *repo, struct got_object_id *id)
274 {
275 	const struct got_error *err = NULL;
276 	struct got_packidx *packidx = NULL;
277 	int idx, tempfd, tempfile_idx;
278 	uint8_t *outbuf = NULL;
279 	off_t size = 0;
280 	size_t hdrlen = 0;
281 	char *path_packfile = NULL;
282 
283 	*obj = got_repo_get_cached_raw_object(repo, id);
284 	if (*obj != NULL) {
285 		(*obj)->refcnt++;
286 		return NULL;
287 	}
288 
289 	err = got_repo_temp_fds_get(&tempfd, &tempfile_idx, repo);
290 	if (err)
291 		return err;
292 
293 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
294 	if (err == NULL) {
295 		struct got_pack *pack = NULL;
296 
297 		err = got_packidx_get_packfile_path(&path_packfile,
298 		    packidx->path_packidx);
299 		if (err)
300 			goto done;
301 
302 		pack = got_repo_get_cached_pack(repo, path_packfile);
303 		if (pack == NULL) {
304 			err = got_repo_cache_pack(&pack, repo, path_packfile,
305 			    packidx);
306 			if (err)
307 				goto done;
308 		}
309 		err = read_packed_object_raw(&outbuf, &size, &hdrlen,
310 		    tempfd, pack, packidx, idx, id);
311 		if (err)
312 			goto done;
313 	} else if (err->code == GOT_ERR_NO_OBJ) {
314 		int fd;
315 
316 		err = got_object_open_loose_fd(&fd, id, repo);
317 		if (err)
318 			goto done;
319 		err = got_object_read_raw(&outbuf, &size, &hdrlen,
320 		    GOT_DELTA_RESULT_SIZE_CACHED_MAX, tempfd, id, fd);
321 		if (close(fd) == -1 && err == NULL)
322 			err = got_error_from_errno("close");
323 		if (err)
324 			goto done;
325 	}
326 
327 	if (outbuf == NULL) {
328 		if (*outfd != -1) {
329 			err = got_error_msg(GOT_ERR_NOT_IMPL, "bad outfd");
330 			goto done;
331 		}
332 
333 		/*
334 		 * Duplicate tempfile descriptor to allow use of
335 		 * fdopen(3) inside got_object_raw_alloc().
336 		 */
337 		*outfd = dup(tempfd);
338 		if (*outfd == -1) {
339 			err = got_error_from_errno("dup");
340 			goto done;
341 		}
342 	}
343 
344 	err = got_object_raw_alloc(obj, outbuf, outfd,
345 	    GOT_DELTA_RESULT_SIZE_CACHED_MAX, hdrlen, size);
346 	if (err)
347 		goto done;
348 
349 	err = got_repo_cache_raw_object(repo, id, *obj);
350 	if (err) {
351 		if (err->code == GOT_ERR_OBJ_EXISTS ||
352 		    err->code == GOT_ERR_OBJ_TOO_LARGE)
353 			err = NULL;
354 	}
355 done:
356 	free(path_packfile);
357 	if (err) {
358 		if (*obj) {
359 			got_object_raw_close(*obj);
360 			*obj = NULL;
361 		}
362 		free(outbuf);
363 		got_repo_temp_fds_put(tempfile_idx, repo);
364 		if (*outfd != -1) {
365 			close(*outfd);
366 			*outfd = -1;
367 		}
368 	} else {
369 		if (((*obj)->f == NULL && (*obj)->fd == -1)) {
370 			/* This raw object is not backed by a file. */
371 			got_repo_temp_fds_put(tempfile_idx, repo);
372 			if (*outfd != -1) {
373 				close(*outfd);
374 				*outfd = -1;
375 			}
376 		} else {
377 			(*obj)->tempfile_idx = tempfile_idx;
378 			(*obj)->close_cb = put_raw_object_tempfile;
379 			(*obj)->close_arg = repo;
380 		}
381 	}
382 	return err;
383 }
384 
385 static const struct got_error *
386 open_commit(struct got_commit_object **commit,
387     struct got_repository *repo, struct got_object_id *id, int check_cache)
388 {
389 	const struct got_error *err = NULL;
390 	struct got_packidx *packidx = NULL;
391 	int idx;
392 	char *path_packfile = NULL;
393 
394 	if (check_cache) {
395 		*commit = got_repo_get_cached_commit(repo, id);
396 		if (*commit != NULL) {
397 			(*commit)->refcnt++;
398 			return NULL;
399 		}
400 	} else
401 		*commit = NULL;
402 
403 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
404 	if (err == NULL) {
405 		struct got_pack *pack = NULL;
406 		struct got_object *obj;
407 		uint8_t *buf;
408 		size_t len;
409 
410 		err = got_packidx_get_packfile_path(&path_packfile,
411 		    packidx->path_packidx);
412 		if (err)
413 			return err;
414 
415 		pack = got_repo_get_cached_pack(repo, path_packfile);
416 		if (pack == NULL) {
417 			err = got_repo_cache_pack(&pack, repo, path_packfile,
418 			    packidx);
419 			if (err)
420 				goto done;
421 		}
422 		err = got_packfile_open_object(&obj, pack, packidx, idx, id);
423 		if (err)
424 			goto done;
425 		err = got_packfile_extract_object_to_mem(&buf, &len,
426 		    obj, pack);
427 		got_object_close(obj);
428 		if (err)
429 			goto done;
430 		err = got_object_parse_commit(commit, buf, len);
431 		free(buf);
432 	} else if (err->code == GOT_ERR_NO_OBJ) {
433 		int fd;
434 
435 		err = got_object_open_loose_fd(&fd, id, repo);
436 		if (err)
437 			return err;
438 		err = got_object_read_commit(commit, fd, id, 0);
439 		if (close(fd) == -1 && err == NULL)
440 			err = got_error_from_errno("close");
441 		if (err)
442 			return err;
443 	}
444 
445 	if (err == NULL) {
446 		(*commit)->refcnt++;
447 		err = got_repo_cache_commit(repo, id, *commit);
448 		if (err) {
449 			if (err->code == GOT_ERR_OBJ_EXISTS ||
450 			    err->code == GOT_ERR_OBJ_TOO_LARGE)
451 				err = NULL;
452 		}
453 	}
454 done:
455 	free(path_packfile);
456 	return err;
457 }
458 
459 const struct got_error *
460 got_object_open_as_commit(struct got_commit_object **commit,
461     struct got_repository *repo, struct got_object_id *id)
462 {
463 	*commit = got_repo_get_cached_commit(repo, id);
464 	if (*commit != NULL) {
465 		(*commit)->refcnt++;
466 		return NULL;
467 	}
468 
469 	return open_commit(commit, repo, id, 0);
470 }
471 
472 const struct got_error *
473 got_object_commit_open(struct got_commit_object **commit,
474     struct got_repository *repo, struct got_object *obj)
475 {
476 	return open_commit(commit, repo, got_object_get_id(obj), 1);
477 }
478 
479 static const struct got_error *
480 open_tree(struct got_tree_object **tree,
481     struct got_repository *repo, struct got_object_id *id, int check_cache)
482 {
483 	const struct got_error *err = NULL;
484 	struct got_packidx *packidx = NULL;
485 	int idx;
486 	char *path_packfile = NULL;
487 	struct got_parsed_tree_entry *entries = NULL;
488 	size_t nentries = 0, nentries_alloc = 0, i;
489 	uint8_t *buf = NULL;
490 
491 	if (check_cache) {
492 		*tree = got_repo_get_cached_tree(repo, id);
493 		if (*tree != NULL) {
494 			(*tree)->refcnt++;
495 			return NULL;
496 		}
497 	} else
498 		*tree = NULL;
499 
500 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
501 	if (err == NULL) {
502 		struct got_pack *pack = NULL;
503 		struct got_object *obj;
504 		size_t len;
505 
506 		err = got_packidx_get_packfile_path(&path_packfile,
507 		    packidx->path_packidx);
508 		if (err)
509 			return err;
510 
511 		pack = got_repo_get_cached_pack(repo, path_packfile);
512 		if (pack == NULL) {
513 			err = got_repo_cache_pack(&pack, repo, path_packfile,
514 			    packidx);
515 			if (err)
516 				goto done;
517 		}
518 		err = got_packfile_open_object(&obj, pack, packidx, idx, id);
519 		if (err)
520 			goto done;
521 		err = got_packfile_extract_object_to_mem(&buf, &len,
522 		    obj, pack);
523 		got_object_close(obj);
524 		if (err)
525 			goto done;
526 		err = got_object_parse_tree(&entries, &nentries,
527 		    &nentries_alloc, buf, len);
528 		if (err)
529 			goto done;
530 	} else if (err->code == GOT_ERR_NO_OBJ) {
531 		int fd;
532 
533 		err = got_object_open_loose_fd(&fd, id, repo);
534 		if (err)
535 			return err;
536 		err = got_object_read_tree(&entries, &nentries,
537 		    &nentries_alloc, &buf, fd, id);
538 		if (close(fd) == -1 && err == NULL)
539 			err = got_error_from_errno("close");
540 		if (err)
541 			goto done;
542 	} else
543 		goto done;
544 
545 	*tree = malloc(sizeof(**tree));
546 	if (*tree == NULL) {
547 		err = got_error_from_errno("malloc");
548 		goto done;
549 	}
550 	(*tree)->entries = calloc(nentries, sizeof(struct got_tree_entry));
551 	if ((*tree)->entries == NULL) {
552 		err = got_error_from_errno("malloc");
553 		goto done;
554 	}
555 	(*tree)->nentries = nentries;
556 	(*tree)->refcnt = 0;
557 
558 	for (i = 0; i < nentries; i++) {
559 		struct got_parsed_tree_entry *pe = &entries[i];
560 		struct got_tree_entry *te = &(*tree)->entries[i];
561 	
562 		if (strlcpy(te->name, pe->name,
563 		    sizeof(te->name)) >= sizeof(te->name)) {
564 			err = got_error(GOT_ERR_NO_SPACE);
565 			goto done;
566 		}
567 		memcpy(te->id.sha1, pe->id, SHA1_DIGEST_LENGTH);
568 		te->mode = pe->mode;
569 		te->idx = i;
570 	}
571 done:
572 	free(path_packfile);
573 	free(entries);
574 	free(buf);
575 	if (err == NULL) {
576 		(*tree)->refcnt++;
577 		err = got_repo_cache_tree(repo, id, *tree);
578 		if (err) {
579 			if (err->code == GOT_ERR_OBJ_EXISTS ||
580 			    err->code == GOT_ERR_OBJ_TOO_LARGE)
581 				err = NULL;
582 		}
583 	}
584 	if (err) {
585 		if (*tree)
586 			free((*tree)->entries);
587 		free(*tree);
588 		*tree = NULL;
589 	}
590 	return err;
591 }
592 
593 const struct got_error *
594 got_object_open_as_tree(struct got_tree_object **tree,
595     struct got_repository *repo, struct got_object_id *id)
596 {
597 	*tree = got_repo_get_cached_tree(repo, id);
598 	if (*tree != NULL) {
599 		(*tree)->refcnt++;
600 		return NULL;
601 	}
602 
603 	return open_tree(tree, repo, id, 0);
604 }
605 
606 const struct got_error *
607 got_object_tree_open(struct got_tree_object **tree,
608     struct got_repository *repo, struct got_object *obj)
609 {
610 	return open_tree(tree, repo, got_object_get_id(obj), 1);
611 }
612 
613 static const struct got_error *
614 read_packed_blob(uint8_t **outbuf, size_t *size, size_t *hdrlen,
615     int outfd, struct got_pack *pack, struct got_packidx *packidx, int idx,
616     struct got_object_id *id, struct got_repository *repo)
617 {
618 	const struct got_error *err = NULL;
619 	struct got_object *obj;
620 	FILE *outfile = NULL, *basefile = NULL, *accumfile = NULL;
621 	uint64_t blob_size;
622 
623 	*hdrlen = 0;
624 
625 	err = got_object_open_from_packfile(&obj, id, pack, packidx, idx,
626 	    repo);
627 	if (err)
628 		return err;
629 
630 	if (obj->flags & GOT_OBJ_FLAG_DELTIFIED) {
631 		err = got_pack_get_max_delta_object_size(&blob_size, obj,
632 		    pack);
633 		if (err)
634 			goto done;
635 	} else
636 		blob_size = obj->size;
637 
638 	if (blob_size <= GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
639 		err = got_packfile_extract_object_to_mem(outbuf, size,
640 		    obj, pack); 
641 	} else {
642 		/*
643 		 * XXX This uses 3 file extra descriptors for no good reason.
644 		 * We should have got_packfile_extract_object_to_fd().
645 		 */
646 		err = wrap_fd(&outfile, outfd);
647 		if (err)
648 			goto done;
649 		err = wrap_fd(&basefile, pack->basefd);
650 		if (err)
651 			goto done;
652 		err = wrap_fd(&accumfile, pack->accumfd);
653 		if (err)
654 			goto done;
655 		err = got_packfile_extract_object(pack, obj, outfile, basefile,
656 		    accumfile);
657 		if (err)
658 			goto done;
659 		*size = obj->size;
660 	}
661 
662 	/* XXX verify checksum? */
663 done:
664 	got_object_close(obj);
665 	if (outfile && fclose(outfile) == EOF && err == NULL)
666 		err = got_error_from_errno("fclose");
667 	if (basefile && fclose(basefile) == EOF && err == NULL)
668 		err = got_error_from_errno("fclose");
669 	if (accumfile && fclose(accumfile) == EOF && err == NULL)
670 		err = got_error_from_errno("fclose");
671 	return err;
672 }
673 
674 static const struct got_error *
675 read_blob(uint8_t **outbuf, size_t *size, size_t *hdrlen, int outfd, int infd,
676     struct got_object_id *id, struct got_repository *repo)
677 {
678 	const struct got_error *err = NULL;
679 	struct got_object *obj = NULL;
680 	FILE *f = NULL;
681 	struct got_object_id expected_id;
682 	struct got_inflate_checksum csum;
683 	struct got_hash ctx;
684 
685 	got_hash_init(&ctx, GOT_HASH_SHA1);
686 	memset(&csum, 0, sizeof(csum));
687 	csum.output_ctx = &ctx;
688 
689 	memcpy(&expected_id, id, sizeof(expected_id));
690 
691 	err = got_object_read_header(&obj, infd);
692 	if (err)
693 		goto done;
694 
695 	if (lseek(infd, SEEK_SET, 0) == -1) {
696 		err = got_error_from_errno("lseek");
697 		goto done;
698 	}
699 
700 	f = fdopen(infd, "rb");
701 	if (f == NULL) {
702 		err = got_error_from_errno("fdopen");
703 		goto done;
704 	}
705 	infd = -1;
706 
707 	if (obj->size + obj->hdrlen <= GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
708 		err = got_inflate_to_mem(outbuf, size, NULL, &csum, f);
709 		if (err)
710 			goto done;
711 	} else {
712 		err = got_inflate_to_fd(size, f, &csum, outfd);
713 		if (err)
714 			goto done;
715 	}
716 
717 	if (*size < obj->hdrlen) {
718 		err = got_error(GOT_ERR_BAD_OBJ_HDR);
719 		goto done;
720 	}
721 
722 	*hdrlen = obj->hdrlen;
723 
724 	got_hash_final_object_id(&ctx, id);
725 	if (got_object_id_cmp(&expected_id, id) != 0) {
726 		err = got_error_checksum(&expected_id);
727 		goto done;
728 	}
729 done:
730 	if (f && fclose(f) == EOF && err == NULL)
731 		err = got_error_from_errno("fclose");
732 	if (infd != -1 && close(infd) == -1 && err == NULL)
733 		err = got_error_from_errno("close");
734 
735 	return err;
736 }
737 
738 static const struct got_error *
739 open_blob(struct got_blob_object **blob, struct got_repository *repo,
740     struct got_object_id *id, size_t blocksize, int outfd)
741 {
742 	const struct got_error *err = NULL;
743 	struct got_packidx *packidx = NULL;
744 	int idx, dfd = -1;
745 	char *path_packfile = NULL;
746 	uint8_t *outbuf;
747 	size_t size, hdrlen;
748 	struct stat sb;
749 
750 	*blob = calloc(1, sizeof(**blob));
751 	if (*blob == NULL)
752 		return got_error_from_errno("calloc");
753 
754 	(*blob)->read_buf = malloc(blocksize);
755 	if ((*blob)->read_buf == NULL) {
756 		err = got_error_from_errno("malloc");
757 		goto done;
758 	}
759 
760 	if (ftruncate(outfd, 0L) == -1) {
761 		err = got_error_from_errno("ftruncate");
762 		goto done;
763 	}
764 	if (lseek(outfd, SEEK_SET, 0) == -1) {
765 		err = got_error_from_errno("lseek");
766 		goto done;
767 	}
768 
769 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
770 	if (err == NULL) {
771 		struct got_pack *pack = NULL;
772 
773 		err = got_packidx_get_packfile_path(&path_packfile,
774 		    packidx->path_packidx);
775 		if (err)
776 			goto done;
777 
778 		pack = got_repo_get_cached_pack(repo, path_packfile);
779 		if (pack == NULL) {
780 			err = got_repo_cache_pack(&pack, repo, path_packfile,
781 			    packidx);
782 			if (err)
783 				goto done;
784 		}
785 		err = read_packed_blob(&outbuf, &size, &hdrlen, outfd,
786 		    pack, packidx, idx, id, repo);
787 	} else if (err->code == GOT_ERR_NO_OBJ) {
788 		int infd;
789 
790 		err = got_object_open_loose_fd(&infd, id, repo);
791 		if (err)
792 			goto done;
793 		err = read_blob(&outbuf, &size, &hdrlen, outfd, infd,
794 		    id, repo);
795 	}
796 	if (err)
797 		goto done;
798 
799 	if (hdrlen > size) {
800 		err = got_error(GOT_ERR_BAD_OBJ_HDR);
801 		goto done;
802 	}
803 
804 	if (outbuf) {
805 		(*blob)->f = fmemopen(outbuf, size, "rb");
806 		if ((*blob)->f == NULL) {
807 			err = got_error_from_errno("fmemopen");
808 			free(outbuf);
809 			goto done;
810 		}
811 		(*blob)->data = outbuf;
812 	} else {
813 		if (fstat(outfd, &sb) == -1) {
814 			err = got_error_from_errno("fstat");
815 			goto done;
816 		}
817 
818 		if (sb.st_size != size) {
819 			err = got_error(GOT_ERR_PRIVSEP_LEN);
820 			goto done;
821 		}
822 
823 		dfd = dup(outfd);
824 		if (dfd == -1) {
825 			err = got_error_from_errno("dup");
826 			goto done;
827 		}
828 
829 		(*blob)->f = fdopen(dfd, "rb");
830 		if ((*blob)->f == NULL) {
831 			err = got_error_from_errno("fdopen");
832 			close(dfd);
833 			dfd = -1;
834 			goto done;
835 		}
836 	}
837 
838 	(*blob)->hdrlen = hdrlen;
839 	(*blob)->blocksize = blocksize;
840 	memcpy(&(*blob)->id, id, sizeof(*id));
841 
842 done:
843 	free(path_packfile);
844 	if (err) {
845 		if (*blob) {
846 			got_object_blob_close(*blob);
847 			*blob = NULL;
848 		}
849 	}
850 	return err;
851 }
852 
853 const struct got_error *
854 got_object_open_as_blob(struct got_blob_object **blob,
855     struct got_repository *repo, struct got_object_id *id, size_t blocksize,
856     int outfd)
857 {
858 	return open_blob(blob, repo, id, blocksize, outfd);
859 }
860 
861 const struct got_error *
862 got_object_blob_open(struct got_blob_object **blob,
863     struct got_repository *repo, struct got_object *obj, size_t blocksize,
864     int outfd)
865 {
866 	return open_blob(blob, repo, got_object_get_id(obj), blocksize, outfd);
867 }
868 
869 static const struct got_error *
870 open_tag(struct got_tag_object **tag, struct got_repository *repo,
871     struct got_object_id *id, int check_cache)
872 {
873 	const struct got_error *err = NULL;
874 	struct got_packidx *packidx = NULL;
875 	int idx;
876 	char *path_packfile = NULL;
877 	struct got_object *obj = NULL;
878 	int obj_type = GOT_OBJ_TYPE_ANY;
879 
880 	if (check_cache) {
881 		*tag = got_repo_get_cached_tag(repo, id);
882 		if (*tag != NULL) {
883 			(*tag)->refcnt++;
884 			return NULL;
885 		}
886 	} else
887 		*tag = NULL;
888 
889 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
890 	if (err == NULL) {
891 		struct got_pack *pack = NULL;
892 		uint8_t *buf = NULL;
893 		size_t len;
894 
895 		err = got_packidx_get_packfile_path(&path_packfile,
896 		    packidx->path_packidx);
897 		if (err)
898 			return err;
899 
900 		pack = got_repo_get_cached_pack(repo, path_packfile);
901 		if (pack == NULL) {
902 			err = got_repo_cache_pack(&pack, repo, path_packfile,
903 			    packidx);
904 			if (err)
905 				goto done;
906 		}
907 
908 		/* Beware of "lightweight" tags: Check object type first. */
909 		err = got_packfile_open_object(&obj, pack, packidx, idx, id);
910 		if (err)
911 			goto done;
912 		obj_type = obj->type;
913 		if (obj_type != GOT_OBJ_TYPE_TAG) {
914 			err = got_error(GOT_ERR_OBJ_TYPE);
915 			got_object_close(obj);
916 			goto done;
917 		}
918 		err = got_packfile_extract_object_to_mem(&buf, &len,
919 		    obj, pack);
920 		got_object_close(obj);
921 		if (err)
922 			goto done;
923 		err = got_object_parse_tag(tag, buf, len);
924 		free(buf);
925 	} else if (err->code == GOT_ERR_NO_OBJ) {
926 		int fd;
927 
928 		err = got_object_open_loose_fd(&fd, id, repo);
929 		if (err)
930 			return err;
931 		err = got_object_read_header(&obj, fd);
932 		if (close(fd) == -1 && err == NULL)
933 			err = got_error_from_errno("close");
934 		if (err)
935 			return err;
936 		obj_type = obj->type;
937 		got_object_close(obj);
938 		if (obj_type != GOT_OBJ_TYPE_TAG)
939 			return got_error(GOT_ERR_OBJ_TYPE);
940 
941 		err = got_object_open_loose_fd(&fd, id, repo);
942 		if (err)
943 			return err;
944 		err = got_object_read_tag(tag, fd, id, 0);
945 		if (close(fd) == -1 && err == NULL)
946 			err = got_error_from_errno("close");
947 		if (err)
948 			return err;
949 	}
950 
951 	if (err == NULL) {
952 		(*tag)->refcnt++;
953 		err = got_repo_cache_tag(repo, id, *tag);
954 		if (err) {
955 			if (err->code == GOT_ERR_OBJ_EXISTS ||
956 			    err->code == GOT_ERR_OBJ_TOO_LARGE)
957 				err = NULL;
958 		}
959 	}
960 done:
961 	free(path_packfile);
962 	return err;
963 }
964 
965 const struct got_error *
966 got_object_open_as_tag(struct got_tag_object **tag,
967     struct got_repository *repo, struct got_object_id *id)
968 {
969 	*tag = got_repo_get_cached_tag(repo, id);
970 	if (*tag != NULL) {
971 		(*tag)->refcnt++;
972 		return NULL;
973 	}
974 
975 	return open_tag(tag, repo, id, 0);
976 }
977 
978 const struct got_error *
979 got_object_tag_open(struct got_tag_object **tag,
980     struct got_repository *repo, struct got_object *obj)
981 {
982 	return open_tag(tag, repo, got_object_get_id(obj), 1);
983 }