1 /*
2  * Copyright (c) 2018, 2019 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <sys/queue.h>
18 #include <sys/tree.h>
19 #include <sys/stat.h>
20 
21 #include <dirent.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <sha1.h>
26 #include <endian.h>
27 #include <limits.h>
28 
29 #include "got_error.h"
30 #include "got_object.h"
31 
32 #include "got_lib_path.h"
33 #include "got_lib_fileindex.h"
34 
35 struct got_fileindex {
36 	struct got_fileindex_tree entries;
37 	int nentries;
38 #define GOT_FILEIDX_MAX_ENTRIES INT_MAX
39 };
40 
41 const struct got_error *
42 got_fileindex_entry_update(struct got_fileindex_entry *entry,
43     const char *ondisk_path, uint8_t *blob_sha1, uint8_t *commit_sha1)
44 {
45 	struct stat sb;
46 
47 	if (lstat(ondisk_path, &sb) != 0)
48 		return got_error_from_errno();
49 
50 	entry->ctime_sec = sb.st_ctime;
51 	entry->ctime_nsec = sb.st_ctimensec;
52 	entry->mtime_sec = sb.st_mtime;
53 	entry->mtime_nsec = sb.st_mtimensec;
54 	entry->uid = sb.st_uid;
55 	entry->gid = sb.st_gid;
56 	entry->size = (sb.st_size & 0xffffffff);
57 	if (sb.st_mode & S_IFLNK)
58 		entry->mode = GOT_FILEIDX_MODE_SYMLINK;
59 	else
60 		entry->mode = GOT_FILEIDX_MODE_REGULAR_FILE;
61 	entry->mode |= ((sb.st_mode & (S_IRWXU | S_IRWXG | S_IRWXO)) <<
62 	    GOT_FILEIDX_MODE_PERMS_SHIFT);
63 	memcpy(entry->blob_sha1, blob_sha1, SHA1_DIGEST_LENGTH);
64 	memcpy(entry->commit_sha1, commit_sha1, SHA1_DIGEST_LENGTH);
65 
66 	return NULL;
67 }
68 
69 const struct got_error *
70 got_fileindex_entry_alloc(struct got_fileindex_entry **entry,
71     const char *ondisk_path, const char *relpath, uint8_t *blob_sha1,
72     uint8_t *commit_sha1)
73 {
74 	size_t len;
75 
76 	*entry = calloc(1, sizeof(**entry));
77 	if (*entry == NULL)
78 		return got_error_from_errno();
79 
80 	(*entry)->path = strdup(relpath);
81 	if ((*entry)->path == NULL) {
82 		const struct got_error *err = got_error_from_errno();
83 		free(*entry);
84 		*entry = NULL;
85 		return err;
86 	}
87 
88 	len = strlen(relpath);
89 	if (len > GOT_FILEIDX_F_PATH_LEN)
90 		len = GOT_FILEIDX_F_PATH_LEN;
91 	(*entry)->flags |= len;
92 
93 	return got_fileindex_entry_update(*entry, ondisk_path, blob_sha1,
94 	    commit_sha1);
95 }
96 
97 void
98 got_fileindex_entry_free(struct got_fileindex_entry *entry)
99 {
100 	free(entry->path);
101 	free(entry);
102 }
103 
104 static const struct got_error *
105 add_entry(struct got_fileindex *fileindex, struct got_fileindex_entry *entry)
106 {
107 	if (fileindex->nentries >= GOT_FILEIDX_MAX_ENTRIES)
108 		return got_error(GOT_ERR_NO_SPACE);
109 
110 	RB_INSERT(got_fileindex_tree, &fileindex->entries, entry);
111 	fileindex->nentries++;
112 	return NULL;
113 }
114 
115 const struct got_error *
116 got_fileindex_entry_add(struct got_fileindex *fileindex,
117     struct got_fileindex_entry *entry)
118 {
119 	/* Flag this entry until it gets written out to disk. */
120 	entry->flags |= GOT_FILEIDX_F_INTENT_TO_ADD;
121 
122 	return add_entry(fileindex, entry);
123 }
124 
125 void
126 got_fileindex_entry_remove(struct got_fileindex *fileindex,
127     struct got_fileindex_entry *entry)
128 {
129 	RB_REMOVE(got_fileindex_tree, &fileindex->entries, entry);
130 	fileindex->nentries--;
131 }
132 
133 struct got_fileindex_entry *
134 got_fileindex_entry_get(struct got_fileindex *fileindex, const char *path)
135 {
136 	struct got_fileindex_entry key;
137 	memset(&key, 0, sizeof(key));
138 	key.path = (char *)path;
139 	return RB_FIND(got_fileindex_tree, &fileindex->entries, &key);
140 }
141 
142 const struct got_error *
143 got_fileindex_for_each_entry_safe(struct got_fileindex *fileindex,
144     got_fileindex_cb cb, void *cb_arg)
145 {
146 	const struct got_error *err;
147 	struct got_fileindex_entry *entry, *tmp;
148 
149 	RB_FOREACH_SAFE(entry, got_fileindex_tree, &fileindex->entries, tmp) {
150 		err = (*cb)(cb_arg, entry);
151 		if (err)
152 			return err;
153 	}
154 	return NULL;
155 }
156 
157 struct got_fileindex *
158 got_fileindex_alloc(void)
159 {
160 	struct got_fileindex *fileindex;
161 
162 	fileindex = calloc(1, sizeof(*fileindex));
163 	if (fileindex == NULL)
164 		return NULL;
165 
166 	RB_INIT(&fileindex->entries);
167 	return fileindex;
168 }
169 
170 void
171 got_fileindex_free(struct got_fileindex *fileindex)
172 {
173 	struct got_fileindex_entry *entry;
174 
175 	while ((entry = RB_MIN(got_fileindex_tree, &fileindex->entries))) {
176 		RB_REMOVE(got_fileindex_tree, &fileindex->entries, entry);
177 		got_fileindex_entry_free(entry);
178 	}
179 	free(fileindex);
180 }
181 
182 static const struct got_error *
183 write_fileindex_val64(SHA1_CTX *ctx, uint64_t val, FILE *outfile)
184 {
185 	size_t n;
186 
187 	val = htobe64(val);
188 	SHA1Update(ctx, (uint8_t *)&val, sizeof(val));
189 	n = fwrite(&val, 1, sizeof(val), outfile);
190 	if (n != sizeof(val))
191 		return got_ferror(outfile, GOT_ERR_IO);
192 	return NULL;
193 }
194 
195 static const struct got_error *
196 write_fileindex_val32(SHA1_CTX *ctx, uint32_t val, FILE *outfile)
197 {
198 	size_t n;
199 
200 	val = htobe32(val);
201 	SHA1Update(ctx, (uint8_t *)&val, sizeof(val));
202 	n = fwrite(&val, 1, sizeof(val), outfile);
203 	if (n != sizeof(val))
204 		return got_ferror(outfile, GOT_ERR_IO);
205 	return NULL;
206 }
207 
208 static const struct got_error *
209 write_fileindex_val16(SHA1_CTX *ctx, uint16_t val, FILE *outfile)
210 {
211 	size_t n;
212 
213 	val = htobe16(val);
214 	SHA1Update(ctx, (uint8_t *)&val, sizeof(val));
215 	n = fwrite(&val, 1, sizeof(val), outfile);
216 	if (n != sizeof(val))
217 		return got_ferror(outfile, GOT_ERR_IO);
218 	return NULL;
219 }
220 
221 static const struct got_error *
222 write_fileindex_path(SHA1_CTX *ctx, const char *path, FILE *outfile)
223 {
224 	size_t n, len, pad = 0;
225 	static const uint8_t zero[8] = { 0 };
226 
227 	len = strlen(path);
228 	while ((len + pad) % 8 != 0)
229 		pad++;
230 	if (pad == 0)
231 		pad = 8; /* NUL-terminate */
232 
233 	SHA1Update(ctx, path, len);
234 	n = fwrite(path, 1, len, outfile);
235 	if (n != len)
236 		return got_ferror(outfile, GOT_ERR_IO);
237 	SHA1Update(ctx, zero, pad);
238 	n = fwrite(zero, 1, pad, outfile);
239 	if (n != pad)
240 		return got_ferror(outfile, GOT_ERR_IO);
241 	return NULL;
242 }
243 
244 static const struct got_error *
245 write_fileindex_entry(SHA1_CTX *ctx, struct got_fileindex_entry *entry,
246     FILE *outfile)
247 {
248 	const struct got_error *err;
249 	size_t n;
250 
251 	err = write_fileindex_val64(ctx, entry->ctime_sec, outfile);
252 	if (err)
253 		return err;
254 	err = write_fileindex_val64(ctx, entry->ctime_nsec, outfile);
255 	if (err)
256 		return err;
257 	err = write_fileindex_val64(ctx, entry->mtime_sec, outfile);
258 	if (err)
259 		return err;
260 	err = write_fileindex_val64(ctx, entry->mtime_nsec, outfile);
261 	if (err)
262 		return err;
263 
264 	err = write_fileindex_val32(ctx, entry->uid, outfile);
265 	if (err)
266 		return err;
267 	err = write_fileindex_val32(ctx, entry->gid, outfile);
268 	if (err)
269 		return err;
270 	err = write_fileindex_val32(ctx, entry->size, outfile);
271 	if (err)
272 		return err;
273 
274 	err = write_fileindex_val16(ctx, entry->mode, outfile);
275 	if (err)
276 		return err;
277 
278 	SHA1Update(ctx, entry->blob_sha1, SHA1_DIGEST_LENGTH);
279 	n = fwrite(entry->blob_sha1, 1, SHA1_DIGEST_LENGTH, outfile);
280 	if (n != SHA1_DIGEST_LENGTH)
281 		return got_ferror(outfile, GOT_ERR_IO);
282 
283 	SHA1Update(ctx, entry->commit_sha1, SHA1_DIGEST_LENGTH);
284 	n = fwrite(entry->commit_sha1, 1, SHA1_DIGEST_LENGTH, outfile);
285 	if (n != SHA1_DIGEST_LENGTH)
286 		return got_ferror(outfile, GOT_ERR_IO);
287 
288 	err = write_fileindex_val32(ctx, entry->flags, outfile);
289 	if (err)
290 		return err;
291 
292 	err = write_fileindex_path(ctx, entry->path, outfile);
293 	return err;
294 }
295 
296 const struct got_error *
297 got_fileindex_write(struct got_fileindex *fileindex, FILE *outfile)
298 {
299 	const struct got_error *err = NULL;
300 	struct got_fileindex_hdr hdr;
301 	SHA1_CTX ctx;
302 	uint8_t sha1[SHA1_DIGEST_LENGTH];
303 	size_t n;
304 	struct got_fileindex_entry *entry;
305 
306 	SHA1Init(&ctx);
307 
308 	hdr.signature = htobe32(GOT_FILE_INDEX_SIGNATURE);
309 	hdr.version = htobe32(GOT_FILE_INDEX_VERSION);
310 	hdr.nentries = htobe32(fileindex->nentries);
311 
312 	SHA1Update(&ctx, (uint8_t *)&hdr.signature, sizeof(hdr.signature));
313 	SHA1Update(&ctx, (uint8_t *)&hdr.version, sizeof(hdr.version));
314 	SHA1Update(&ctx, (uint8_t *)&hdr.nentries, sizeof(hdr.nentries));
315 	n = fwrite(&hdr.signature, 1, sizeof(hdr.signature), outfile);
316 	if (n != sizeof(hdr.signature))
317 		return got_ferror(outfile, GOT_ERR_IO);
318 	n = fwrite(&hdr.version, 1, sizeof(hdr.version), outfile);
319 	if (n != sizeof(hdr.version))
320 		return got_ferror(outfile, GOT_ERR_IO);
321 	n = fwrite(&hdr.nentries, 1, sizeof(hdr.nentries), outfile);
322 	if (n != sizeof(hdr.nentries))
323 		return got_ferror(outfile, GOT_ERR_IO);
324 
325 	RB_FOREACH(entry, got_fileindex_tree, &fileindex->entries) {
326 		entry->flags &= ~GOT_FILEIDX_F_INTENT_TO_ADD;
327 		err = write_fileindex_entry(&ctx, entry, outfile);
328 		if (err)
329 			return err;
330 	}
331 
332 	SHA1Final(sha1, &ctx);
333 	n = fwrite(sha1, 1, sizeof(sha1), outfile);
334 	if (n != sizeof(sha1))
335 		return got_ferror(outfile, GOT_ERR_IO);
336 
337 	if (fflush(outfile) != 0)
338 		return got_error_from_errno();
339 
340 	return NULL;
341 }
342 
343 static const struct got_error *
344 read_fileindex_val64(uint64_t *val, SHA1_CTX *ctx, FILE *infile)
345 {
346 	size_t n;
347 
348 	n = fread(val, 1, sizeof(*val), infile);
349 	if (n != sizeof(*val))
350 		return got_ferror(infile, GOT_ERR_FILEIDX_BAD);
351 	SHA1Update(ctx, (uint8_t *)val, sizeof(*val));
352 	*val = be64toh(*val);
353 	return NULL;
354 }
355 
356 static const struct got_error *
357 read_fileindex_val32(uint32_t *val, SHA1_CTX *ctx, FILE *infile)
358 {
359 	size_t n;
360 
361 	n = fread(val, 1, sizeof(*val), infile);
362 	if (n != sizeof(*val))
363 		return got_ferror(infile, GOT_ERR_FILEIDX_BAD);
364 	SHA1Update(ctx, (uint8_t *)val, sizeof(*val));
365 	*val = be32toh(*val);
366 	return NULL;
367 }
368 
369 static const struct got_error *
370 read_fileindex_val16(uint16_t *val, SHA1_CTX *ctx, FILE *infile)
371 {
372 	size_t n;
373 
374 	n = fread(val, 1, sizeof(*val), infile);
375 	if (n != sizeof(*val))
376 		return got_ferror(infile, GOT_ERR_FILEIDX_BAD);
377 	SHA1Update(ctx, (uint8_t *)val, sizeof(*val));
378 	*val = be16toh(*val);
379 	return NULL;
380 }
381 
382 static const struct got_error *
383 read_fileindex_path(char **path, SHA1_CTX *ctx, FILE *infile)
384 {
385 	const struct got_error *err = NULL;
386 	uint8_t buf[8];
387 	size_t n, len = 0, totlen = sizeof(buf);
388 
389 	*path = malloc(totlen);
390 	if (*path == NULL)
391 		return got_error_from_errno();
392 
393 	do {
394 		n = fread(buf, 1, sizeof(buf), infile);
395 		if (n != sizeof(buf))
396 			return got_ferror(infile, GOT_ERR_FILEIDX_BAD);
397 		if (len + sizeof(buf) > totlen) {
398 			char *p = reallocarray(*path, totlen + sizeof(buf), 1);
399 			if (p == NULL) {
400 				err = got_error_from_errno();
401 				break;
402 			}
403 			totlen += sizeof(buf);
404 			*path = p;
405 		}
406 		SHA1Update(ctx, buf, sizeof(buf));
407 		memcpy(*path + len, buf, sizeof(buf));
408 		len += sizeof(buf);
409 	} while (memchr(buf, '\0', sizeof(buf)) == NULL);
410 
411 	if (err) {
412 		free(*path);
413 		*path = NULL;
414 	}
415 	return err;
416 }
417 
418 static const struct got_error *
419 read_fileindex_entry(struct got_fileindex_entry **entryp, SHA1_CTX *ctx,
420     FILE *infile)
421 {
422 	const struct got_error *err;
423 	struct got_fileindex_entry *entry;
424 	size_t n;
425 
426 	*entryp = NULL;
427 
428 	entry = calloc(1, sizeof(*entry));
429 	if (entry == NULL)
430 		return got_error_from_errno();
431 
432 	err = read_fileindex_val64(&entry->ctime_sec, ctx, infile);
433 	if (err)
434 		goto done;
435 	err = read_fileindex_val64(&entry->ctime_nsec, ctx, infile);
436 	if (err)
437 		goto done;
438 	err = read_fileindex_val64(&entry->mtime_sec, ctx, infile);
439 	if (err)
440 		goto done;
441 	err = read_fileindex_val64(&entry->mtime_nsec, ctx, infile);
442 	if (err)
443 		goto done;
444 
445 	err = read_fileindex_val32(&entry->uid, ctx, infile);
446 	if (err)
447 		goto done;
448 	err = read_fileindex_val32(&entry->gid, ctx, infile);
449 	if (err)
450 		goto done;
451 	err = read_fileindex_val32(&entry->size, ctx, infile);
452 	if (err)
453 		goto done;
454 
455 	err = read_fileindex_val16(&entry->mode, ctx, infile);
456 	if (err)
457 		goto done;
458 
459 	n = fread(entry->blob_sha1, 1, SHA1_DIGEST_LENGTH, infile);
460 	if (n != SHA1_DIGEST_LENGTH) {
461 		err = got_ferror(infile, GOT_ERR_FILEIDX_BAD);
462 		goto done;
463 	}
464 	SHA1Update(ctx, entry->blob_sha1, SHA1_DIGEST_LENGTH);
465 
466 	n = fread(entry->commit_sha1, 1, SHA1_DIGEST_LENGTH, infile);
467 	if (n != SHA1_DIGEST_LENGTH) {
468 		err = got_ferror(infile, GOT_ERR_FILEIDX_BAD);
469 		goto done;
470 	}
471 	SHA1Update(ctx, entry->commit_sha1, SHA1_DIGEST_LENGTH);
472 
473 	err = read_fileindex_val32(&entry->flags, ctx, infile);
474 	if (err)
475 		goto done;
476 
477 	err = read_fileindex_path(&entry->path, ctx, infile);
478 done:
479 	if (err)
480 		free(entry);
481 	else
482 		*entryp = entry;
483 	return err;
484 }
485 
486 const struct got_error *
487 got_fileindex_read(struct got_fileindex *fileindex, FILE *infile)
488 {
489 	const struct got_error *err = NULL;
490 	struct got_fileindex_hdr hdr;
491 	SHA1_CTX ctx;
492 	struct got_fileindex_entry *entry;
493 	uint8_t sha1_expected[SHA1_DIGEST_LENGTH];
494 	uint8_t sha1[SHA1_DIGEST_LENGTH];
495 	size_t n;
496 	int i;
497 
498 	SHA1Init(&ctx);
499 
500 	n = fread(&hdr.signature, 1, sizeof(hdr.signature), infile);
501 	if (n != sizeof(hdr.signature)) {
502 		if (n == 0) /* EOF */
503 			return NULL;
504 		return got_ferror(infile, GOT_ERR_FILEIDX_BAD);
505 	}
506 	n = fread(&hdr.version, 1, sizeof(hdr.version), infile);
507 	if (n != sizeof(hdr.version)) {
508 		if (n == 0) /* EOF */
509 			return NULL;
510 		return got_ferror(infile, GOT_ERR_FILEIDX_BAD);
511 	}
512 	n = fread(&hdr.nentries, 1, sizeof(hdr.nentries), infile);
513 	if (n != sizeof(hdr.nentries)) {
514 		if (n == 0) /* EOF */
515 			return NULL;
516 		return got_ferror(infile, GOT_ERR_FILEIDX_BAD);
517 	}
518 
519 	SHA1Update(&ctx, (uint8_t *)&hdr.signature, sizeof(hdr.signature));
520 	SHA1Update(&ctx, (uint8_t *)&hdr.version, sizeof(hdr.version));
521 	SHA1Update(&ctx, (uint8_t *)&hdr.nentries, sizeof(hdr.nentries));
522 
523 	hdr.signature = be32toh(hdr.signature);
524 	hdr.version = be32toh(hdr.version);
525 	hdr.nentries = be32toh(hdr.nentries);
526 
527 	if (hdr.signature != GOT_FILE_INDEX_SIGNATURE)
528 		return got_error(GOT_ERR_FILEIDX_SIG);
529 	if (hdr.version != GOT_FILE_INDEX_VERSION)
530 		return got_error(GOT_ERR_FILEIDX_VER);
531 
532 	for (i = 0; i < hdr.nentries; i++) {
533 		err = read_fileindex_entry(&entry, &ctx, infile);
534 		if (err)
535 			return err;
536 		err = add_entry(fileindex, entry);
537 		if (err)
538 			return err;
539 	}
540 
541 	n = fread(sha1_expected, 1, sizeof(sha1_expected), infile);
542 	if (n != sizeof(sha1_expected))
543 		return got_ferror(infile, GOT_ERR_FILEIDX_BAD);
544 	SHA1Final(sha1, &ctx);
545 	if (memcmp(sha1, sha1_expected, SHA1_DIGEST_LENGTH) != 0)
546 		return got_error(GOT_ERR_FILEIDX_CSUM);
547 
548 	return NULL;
549 }
550 
551 struct got_fileindex_entry *
552 walk_fileindex(struct got_fileindex *fileindex, struct got_fileindex_entry *ie)
553 {
554 	struct got_fileindex_entry *next;
555 
556 	next = RB_NEXT(got_fileindex_tree, &fileindex->entries, ie);
557 
558 	/* Skip entries which were newly added by diff callbacks. */
559 	while (next && (next->flags & GOT_FILEIDX_F_INTENT_TO_ADD))
560 		next = RB_NEXT(got_fileindex_tree, &fileindex->entries, next);
561 
562 	return next;
563 }
564 
565 static const struct got_error *
566 diff_fileindex_tree(struct got_fileindex *, struct got_fileindex_entry **,
567     struct got_tree_object *, const char *, struct got_repository *,
568     struct got_fileindex_diff_tree_cb *, void *);
569 
570 static const struct got_error *
571 walk_tree(struct got_tree_entry **next, struct got_fileindex *fileindex,
572     struct got_fileindex_entry **ie, struct got_tree_entry *te,
573     const char *path, struct got_repository *repo,
574     struct got_fileindex_diff_tree_cb *cb, void *cb_arg)
575 {
576 	const struct got_error *err = NULL;
577 
578 	if (S_ISDIR(te->mode)) {
579 		char *subpath;
580 		struct got_tree_object *subtree;
581 
582 		if (asprintf(&subpath, "%s%s%s", path,
583 		    path[0] == '\0' ? "" : "/", te->name) == -1)
584 			return got_error_from_errno();
585 
586 		err = got_object_open_as_tree(&subtree, repo, te->id);
587 		if (err) {
588 			free(subpath);
589 			return err;
590 		}
591 
592 		err = diff_fileindex_tree(fileindex, ie, subtree,
593 		    subpath, repo, cb, cb_arg);
594 		free(subpath);
595 		got_object_tree_close(subtree);
596 		if (err)
597 			return err;
598 	}
599 
600 	*next = SIMPLEQ_NEXT(te, entry);
601 	return NULL;
602 }
603 
604 /*
605  * Decide whether a fileindex entry path is equivalent to a tree entry path,
606  * and if it is not, then decide which of the two should be processed first.
607  */
608 static int
609 cmp_entries(const char *ie_path, const char *parent_path,
610     size_t parent_len, const char *te_name)
611 {
612 	int cmp = strncmp(ie_path, parent_path, parent_len);
613 	if (cmp == 0) {
614 		const char *ie_name = ie_path + parent_len;
615 		while (ie_name[0] == '/')
616 			ie_name++;
617 		cmp = strcmp(ie_name, te_name);
618 	}
619 	return cmp;
620 
621 }
622 
623 static const struct got_error *
624 diff_fileindex_tree(struct got_fileindex *fileindex,
625     struct got_fileindex_entry **ie, struct got_tree_object *tree,
626     const char *path, struct got_repository *repo,
627     struct got_fileindex_diff_tree_cb *cb, void *cb_arg)
628 {
629 	const struct got_error *err = NULL;
630 	struct got_tree_entry *te = NULL;
631 	size_t path_len = strlen(path);
632 	const struct got_tree_entries *entries;
633 	struct got_fileindex_entry *next;
634 
635 	entries = got_object_tree_get_entries(tree);
636 	te = SIMPLEQ_FIRST(&entries->head);
637 	do {
638 		if (te && *ie) {
639 			int cmp = cmp_entries((*ie)->path, path, path_len,
640 			    te->name);
641 			if (cmp == 0) {
642 				err = cb->diff_old_new(cb_arg, *ie, te,
643 				    path);
644 				if (err)
645 					break;
646 				*ie = walk_fileindex(fileindex, *ie);
647 				err = walk_tree(&te, fileindex, ie, te,
648 				    path, repo, cb, cb_arg);
649 			} else if (cmp < 0 ) {
650 				next = walk_fileindex(fileindex, *ie);
651 				err = cb->diff_old(cb_arg, *ie, path);
652 				if (err)
653 					break;
654 				*ie = next;
655 			} else {
656 				err = cb->diff_new(cb_arg, te, path);
657 				if (err)
658 					break;
659 				err = walk_tree(&te, fileindex, ie, te,
660 				    path, repo, cb, cb_arg);
661 			}
662 			if (err)
663 				break;
664 		} else if (*ie) {
665 			next = walk_fileindex(fileindex, *ie);
666 			err = cb->diff_old(cb_arg, *ie, path);
667 			if (err)
668 				break;
669 			*ie = next;
670 		} else if (te) {
671 			err = cb->diff_new(cb_arg, te, path);
672 			if (err)
673 				break;
674 			err = walk_tree(&te, fileindex, ie, te, path, repo, cb,
675 			    cb_arg);
676 			if (err)
677 				break;
678 		}
679 	} while ((*ie && got_path_is_child((*ie)->path, path, path_len)) || te);
680 
681 	return err;
682 }
683 
684 const struct got_error *
685 got_fileindex_diff_tree(struct got_fileindex *fileindex,
686     struct got_tree_object *tree, struct got_repository *repo,
687     struct got_fileindex_diff_tree_cb *cb, void *cb_arg)
688 {
689 	struct got_fileindex_entry *min;
690 	min = RB_MIN(got_fileindex_tree, &fileindex->entries);
691 	return diff_fileindex_tree(fileindex, &min, tree, "", repo, cb, cb_arg);
692 }
693 
694 static const struct got_error *
695 diff_fileindex_dir(struct got_fileindex *, struct got_fileindex_entry **, DIR *,
696     const char *, struct got_repository *, struct got_fileindex_diff_dir_cb *,
697     void *);
698 
699 static const struct got_error *
700 walk_dir(struct dirent **next, struct got_fileindex *fileindex,
701     struct got_fileindex_entry **ie, struct dirent *de, const char *path,
702     DIR *dir, struct got_repository *repo,
703     struct got_fileindex_diff_dir_cb *cb, void *cb_arg)
704 {
705 	const struct got_error *err = NULL;
706 
707 	if (de->d_type == DT_DIR) {
708 		char *subpath;
709 		DIR *subdir;
710 
711 		if (asprintf(&subpath, "%s%s%s", path,
712 		    path[0] == '\0' ? "" : "/", de->d_name) == -1)
713 			return got_error_from_errno();
714 
715 		subdir = opendir(subpath);
716 		if (subdir == NULL) {
717 			free(subpath);
718 			return got_error_from_errno();
719 		}
720 
721 		err = diff_fileindex_dir(fileindex, ie, subdir, subpath, repo,
722 		    cb, cb_arg);
723 		free(subpath);
724 		closedir(subdir);
725 		if (err)
726 			return err;
727 	}
728 
729 	*next = readdir(dir);
730 	return NULL;
731 }
732 
733 static const struct got_error *
734 diff_fileindex_dir(struct got_fileindex *fileindex,
735     struct got_fileindex_entry **ie, DIR *dir, const char *path,
736     struct got_repository *repo, struct got_fileindex_diff_dir_cb *cb,
737     void *cb_arg)
738 {
739 	const struct got_error *err = NULL;
740 	struct dirent *de = NULL;
741 	size_t path_len = strlen(path);
742 	struct got_fileindex_entry *next;
743 
744 	de = readdir(dir);
745 	do {
746 		if (de && *ie) {
747 			int cmp = cmp_entries((*ie)->path, path, path_len,
748 			    de->d_name);
749 			if (cmp == 0) {
750 				err = cb->diff_old_new(cb_arg, *ie, de, path);
751 				if (err)
752 					break;
753 				*ie = walk_fileindex(fileindex, *ie);
754 				err = walk_dir(&de, fileindex, ie, de, path,
755 				    dir, repo, cb, cb_arg);
756 			} else if (cmp < 0 ) {
757 				next = walk_fileindex(fileindex, *ie);
758 				err = cb->diff_old(cb_arg, *ie, path);
759 				if (err)
760 					break;
761 				*ie = next;
762 			} else {
763 				err = cb->diff_new(cb_arg, de, path);
764 				if (err)
765 					break;
766 				err = walk_dir(&de, fileindex, ie, de, path,
767 				    dir, repo, cb, cb_arg);
768 			}
769 			if (err)
770 				break;
771 		}
772 	} while ((*ie && got_path_is_child((*ie)->path, path, path_len)) || de);
773 
774 	return err;
775 }
776 
777 const struct got_error *
778 got_fileindex_diff_dir(struct got_fileindex *fileindex, DIR *dir,
779     struct got_repository *repo, struct got_fileindex_diff_dir_cb *cb,
780     void *cb_arg)
781 {
782 	struct got_fileindex_entry *min;
783 	min = RB_MIN(got_fileindex_tree, &fileindex->entries);
784 	return diff_fileindex_dir(fileindex, &min, dir, "", repo, cb, cb_arg);
785 }
786 
787 RB_GENERATE(got_fileindex_tree, got_fileindex_entry, entry, got_fileindex_cmp);