1 /*
2  * Copyright (c) 2020 Ori Bernstein
3  * Copyright (c) 2021 Stefan Sperling <stsp@openbsd.org>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #include <sys/types.h>
19 #include <sys/queue.h>
20 #include <sys/tree.h>
21 #include <sys/uio.h>
22 #include <sys/stat.h>
23 #include <sys/time.h>
24 #include <sys/mman.h>
25 
26 #include <endian.h>
27 #include <errno.h>
28 #include <stdint.h>
29 #include <imsg.h>
30 #include <inttypes.h>
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <string.h>
34 #include <sha1.h>
35 #include <time.h>
36 #include <unistd.h>
37 #include <limits.h>
38 #include <zlib.h>
39 
40 #include "got_error.h"
41 #include "got_cancel.h"
42 #include "got_object.h"
43 #include "got_path.h"
44 #include "got_reference.h"
45 #include "got_repository_admin.h"
46 
47 #include "got_lib_deltify.h"
48 #include "got_lib_delta.h"
49 #include "got_lib_object.h"
50 #include "got_lib_object_idset.h"
51 #include "got_lib_object_cache.h"
52 #include "got_lib_deflate.h"
53 #include "got_lib_pack.h"
54 #include "got_lib_pack_create.h"
55 #include "got_lib_privsep.h"
56 #include "got_lib_repository.h"
57 #include "got_lib_ratelimit.h"
58 #include "got_lib_inflate.h"
59 
60 #include "murmurhash2.h"
61 
62 #ifndef MIN
63 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
64 #endif
65 
66 #ifndef MAX
67 #define	MAX(_a,_b) ((_a) > (_b) ? (_a) : (_b))
68 #endif
69 
70 #ifndef nitems
71 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
72 #endif
73 
74 struct got_pack_meta {
75 	struct got_object_id id;
76 	uint32_t path_hash;
77 	int	obj_type;
78 	off_t	size;
79 	time_t	mtime;
80 
81 	/* The best delta we picked */
82 	struct got_pack_meta *head;
83 	struct got_pack_meta *prev;
84 	unsigned char *delta_buf; /* if encoded in memory (compressed) */
85 	off_t	delta_offset;	/* offset in delta cache file (compressed) */
86 	off_t	delta_len;	/* encoded delta length */
87 	off_t	delta_compressed_len; /* encoded+compressed delta length */
88 	int	nchain;
89 
90 	off_t   reused_delta_offset; /* offset of delta in reused pack file */
91 	struct got_object_id *base_obj_id;
92 
93 	/* Only used for delta window */
94 	struct got_delta_table *dtab;
95 
96 	/* Only used for writing offset deltas */
97 	off_t	off;
98 };
99 
100 struct got_pack_metavec {
101 	struct got_pack_meta **meta;
102 	int nmeta;
103 	int metasz;
104 };
105 
106 static const struct got_error *
107 alloc_meta(struct got_pack_meta **new, struct got_object_id *id,
108     const char *path, int obj_type, time_t mtime, uint32_t seed)
109 {
110 	struct got_pack_meta *m;
111 
112 	*new = NULL;
113 
114 	m = calloc(1, sizeof(*m));
115 	if (m == NULL)
116 		return got_error_from_errno("calloc");
117 
118 	memcpy(&m->id, id, sizeof(m->id));
119 
120 	m->path_hash = murmurhash2(path, strlen(path), seed);
121 	m->obj_type = obj_type;
122 	m->mtime = mtime;
123 	*new = m;
124 	return NULL;
125 }
126 
127 static void
128 clear_meta(struct got_pack_meta *meta)
129 {
130 	if (meta == NULL)
131 		return;
132 	meta->path_hash = 0;
133 	free(meta->delta_buf);
134 	meta->delta_buf = NULL;
135 	free(meta->base_obj_id);
136 	meta->base_obj_id = NULL;
137 	meta->reused_delta_offset = 0;
138 }
139 
140 static void
141 free_nmeta(struct got_pack_meta **meta, int nmeta)
142 {
143 	int i;
144 
145 	for (i = 0; i < nmeta; i++)
146 		clear_meta(meta[i]);
147 	free(meta);
148 }
149 
150 static int
151 delta_order_cmp(const void *pa, const void *pb)
152 {
153 	struct got_pack_meta *a, *b;
154 
155 	a = *(struct got_pack_meta **)pa;
156 	b = *(struct got_pack_meta **)pb;
157 
158 	if (a->obj_type != b->obj_type)
159 		return a->obj_type - b->obj_type;
160 	if (a->path_hash < b->path_hash)
161 		return -1;
162 	if (a->path_hash > b->path_hash)
163 		return 1;
164 	if (a->mtime < b->mtime)
165 		return -1;
166 	if (a->mtime > b->mtime)
167 		return 1;
168 	return got_object_id_cmp(&a->id, &b->id);
169 }
170 
171 static off_t
172 delta_size(struct got_delta_instruction *deltas, int ndeltas)
173 {
174 	int i;
175 	off_t size = 32;
176 	for (i = 0; i < ndeltas; i++) {
177 		if (deltas[i].copy)
178 			size += GOT_DELTA_SIZE_SHIFT;
179 		else
180 			size += deltas[i].len + 1;
181 	}
182 	return size;
183 }
184 
185 static const struct got_error *
186 append(unsigned char **p, size_t *len, off_t *sz, void *seg, int nseg)
187 {
188 	char *n;
189 
190 	if (*len + nseg >= *sz) {
191 		while (*len + nseg >= *sz)
192 			*sz += *sz / 2;
193 		n = realloc(*p, *sz);
194 		if (n == NULL)
195 			return got_error_from_errno("realloc");
196 		*p = n;
197 	}
198 	memcpy(*p + *len, seg, nseg);
199 	*len += nseg;
200 	return NULL;
201 }
202 
203 static const struct got_error *
204 encode_delta_in_mem(struct got_pack_meta *m, struct got_raw_object *o,
205     struct got_delta_instruction *deltas, int ndeltas,
206     off_t delta_size, off_t base_size)
207 {
208 	const struct got_error *err;
209 	unsigned char buf[16], *bp;
210 	int i, j;
211 	size_t len = 0, compressed_len;
212 	off_t bufsize = delta_size;
213 	off_t n;
214 	struct got_delta_instruction *d;
215 	uint8_t *delta_buf;
216 
217 	delta_buf = malloc(bufsize);
218 	if (delta_buf == NULL)
219 		return got_error_from_errno("malloc");
220 
221 	/* base object size */
222 	buf[0] = base_size & GOT_DELTA_SIZE_VAL_MASK;
223 	n = base_size >> GOT_DELTA_SIZE_SHIFT;
224 	for (i = 1; n > 0; i++) {
225 		buf[i - 1] |= GOT_DELTA_SIZE_MORE;
226 		buf[i] = n & GOT_DELTA_SIZE_VAL_MASK;
227 		n >>= GOT_DELTA_SIZE_SHIFT;
228 	}
229 	err = append(&delta_buf, &len, &bufsize, buf, i);
230 	if (err)
231 		goto done;
232 
233 	/* target object size */
234 	buf[0] = o->size & GOT_DELTA_SIZE_VAL_MASK;
235 	n = o->size >> GOT_DELTA_SIZE_SHIFT;
236 	for (i = 1; n > 0; i++) {
237 		buf[i - 1] |= GOT_DELTA_SIZE_MORE;
238 		buf[i] = n & GOT_DELTA_SIZE_VAL_MASK;
239 		n >>= GOT_DELTA_SIZE_SHIFT;
240 	}
241 	err = append(&delta_buf, &len, &bufsize, buf, i);
242 	if (err)
243 		goto done;
244 
245 	for (j = 0; j < ndeltas; j++) {
246 		d = &deltas[j];
247 		if (d->copy) {
248 			n = d->offset;
249 			bp = &buf[1];
250 			buf[0] = GOT_DELTA_BASE_COPY;
251 			for (i = 0; i < 4; i++) {
252 				/* DELTA_COPY_OFF1 ... DELTA_COPY_OFF4 */
253 				buf[0] |= 1 << i;
254 				*bp++ = n & 0xff;
255 				n >>= 8;
256 				if (n == 0)
257 					break;
258 			}
259 
260 			n = d->len;
261 			if (n != GOT_DELTA_COPY_DEFAULT_LEN) {
262 				/* DELTA_COPY_LEN1 ... DELTA_COPY_LEN3 */
263 				for (i = 0; i < 3 && n > 0; i++) {
264 					buf[0] |= 1 << (i + 4);
265 					*bp++ = n & 0xff;
266 					n >>= 8;
267 				}
268 			}
269 			err = append(&delta_buf, &len, &bufsize,
270 			    buf, bp - buf);
271 			if (err)
272 				goto done;
273 		} else if (o->f == NULL) {
274 			n = 0;
275 			while (n != d->len) {
276 				buf[0] = (d->len - n < 127) ? d->len - n : 127;
277 				err = append(&delta_buf, &len, &bufsize,
278 				    buf, 1);
279 				if (err)
280 					goto done;
281 				err = append(&delta_buf, &len, &bufsize,
282 				    o->data + o->hdrlen + d->offset + n,
283 				    buf[0]);
284 				if (err)
285 					goto done;
286 				n += buf[0];
287 			}
288 		} else {
289 			char content[128];
290 			size_t r;
291 			if (fseeko(o->f, o->hdrlen + d->offset, SEEK_SET) == -1) {
292 				err = got_error_from_errno("fseeko");
293 				goto done;
294 			}
295 			n = 0;
296 			while (n != d->len) {
297 				buf[0] = (d->len - n < 127) ? d->len - n : 127;
298 				err = append(&delta_buf, &len, &bufsize,
299 				    buf, 1);
300 				if (err)
301 					goto done;
302 				r = fread(content, 1, buf[0], o->f);
303 				if (r != buf[0]) {
304 					err = got_ferror(o->f, GOT_ERR_IO);
305 					goto done;
306 				}
307 				err = append(&delta_buf, &len, &bufsize,
308 				    content, buf[0]);
309 				if (err)
310 					goto done;
311 				n += buf[0];
312 			}
313 		}
314 	}
315 
316 	err = got_deflate_to_mem_mmap(&m->delta_buf, &compressed_len,
317 	    NULL, NULL, delta_buf, 0, len);
318 	if (err)
319 		goto done;
320 
321 	m->delta_len = len;
322 	m->delta_compressed_len = compressed_len;
323 done:
324 	free(delta_buf);
325 	return err;
326 }
327 
328 static const struct got_error *
329 encode_delta(struct got_pack_meta *m, struct got_raw_object *o,
330     struct got_delta_instruction *deltas, int ndeltas,
331     off_t base_size, FILE *f)
332 {
333 	const struct got_error *err;
334 	unsigned char buf[16], *bp;
335 	int i, j;
336 	off_t n;
337 	struct got_deflate_buf zb;
338 	struct got_delta_instruction *d;
339 	off_t delta_len = 0, compressed_len = 0;
340 
341 	err = got_deflate_init(&zb, NULL, GOT_DEFLATE_BUFSIZE);
342 	if (err)
343 		return err;
344 
345 	/* base object size */
346 	buf[0] = base_size & GOT_DELTA_SIZE_VAL_MASK;
347 	n = base_size >> GOT_DELTA_SIZE_SHIFT;
348 	for (i = 1; n > 0; i++) {
349 		buf[i - 1] |= GOT_DELTA_SIZE_MORE;
350 		buf[i] = n & GOT_DELTA_SIZE_VAL_MASK;
351 		n >>= GOT_DELTA_SIZE_SHIFT;
352 	}
353 
354 	err = got_deflate_append_to_file_mmap(&zb, &compressed_len,
355 	    buf, 0, i, f, NULL);
356 	if (err)
357 		goto done;
358 	delta_len += i;
359 
360 	/* target object size */
361 	buf[0] = o->size & GOT_DELTA_SIZE_VAL_MASK;
362 	n = o->size >> GOT_DELTA_SIZE_SHIFT;
363 	for (i = 1; n > 0; i++) {
364 		buf[i - 1] |= GOT_DELTA_SIZE_MORE;
365 		buf[i] = n & GOT_DELTA_SIZE_VAL_MASK;
366 		n >>= GOT_DELTA_SIZE_SHIFT;
367 	}
368 
369 	err = got_deflate_append_to_file_mmap(&zb, &compressed_len,
370 	    buf, 0, i, f, NULL);
371 	if (err)
372 		goto done;
373 	delta_len += i;
374 
375 	for (j = 0; j < ndeltas; j++) {
376 		d = &deltas[j];
377 		if (d->copy) {
378 			n = d->offset;
379 			bp = &buf[1];
380 			buf[0] = GOT_DELTA_BASE_COPY;
381 			for (i = 0; i < 4; i++) {
382 				/* DELTA_COPY_OFF1 ... DELTA_COPY_OFF4 */
383 				buf[0] |= 1 << i;
384 				*bp++ = n & 0xff;
385 				n >>= 8;
386 				if (n == 0)
387 					break;
388 			}
389 			n = d->len;
390 			if (n != GOT_DELTA_COPY_DEFAULT_LEN) {
391 				/* DELTA_COPY_LEN1 ... DELTA_COPY_LEN3 */
392 				for (i = 0; i < 3 && n > 0; i++) {
393 					buf[0] |= 1 << (i + 4);
394 					*bp++ = n & 0xff;
395 					n >>= 8;
396 				}
397 			}
398 			err = got_deflate_append_to_file_mmap(&zb,
399 			    &compressed_len, buf, 0, bp - buf, f, NULL);
400 			if (err)
401 				goto done;
402 			delta_len += (bp - buf);
403 		} else if (o->f == NULL) {
404 			n = 0;
405 			while (n != d->len) {
406 				buf[0] = (d->len - n < 127) ? d->len - n : 127;
407 				err = got_deflate_append_to_file_mmap(&zb,
408 				    &compressed_len, buf, 0, 1, f, NULL);
409 				if (err)
410 					goto done;
411 				delta_len++;
412 				err = got_deflate_append_to_file_mmap(&zb,
413 				    &compressed_len,
414 				    o->data + o->hdrlen + d->offset + n, 0,
415 				    buf[0], f, NULL);
416 				if (err)
417 					goto done;
418 				delta_len += buf[0];
419 				n += buf[0];
420 			}
421 		} else {
422 			char content[128];
423 			size_t r;
424 			if (fseeko(o->f, o->hdrlen + d->offset, SEEK_SET) == -1) {
425 				err = got_error_from_errno("fseeko");
426 				goto done;
427 			}
428 			n = 0;
429 			while (n != d->len) {
430 				buf[0] = (d->len - n < 127) ? d->len - n : 127;
431 				err = got_deflate_append_to_file_mmap(&zb,
432 				    &compressed_len, buf, 0, 1, f, NULL);
433 				if (err)
434 					goto done;
435 				delta_len++;
436 				r = fread(content, 1, buf[0], o->f);
437 				if (r != buf[0]) {
438 					err = got_ferror(o->f, GOT_ERR_IO);
439 					goto done;
440 				}
441 				err = got_deflate_append_to_file_mmap(&zb,
442 				    &compressed_len, content, 0, buf[0], f,
443 				    NULL);
444 				if (err)
445 					goto done;
446 				delta_len += buf[0];
447 				n += buf[0];
448 			}
449 		}
450 	}
451 
452 	err = got_deflate_flush(&zb, f, NULL, &compressed_len);
453 	if (err)
454 		goto done;
455 
456 	/* sanity check */
457 	if (compressed_len != ftello(f) - m->delta_offset) {
458 		err = got_error(GOT_ERR_COMPRESSION);
459 		goto done;
460 	}
461 
462 	m->delta_len = delta_len;
463 	m->delta_compressed_len = compressed_len;
464 done:
465 	got_deflate_end(&zb);
466 	return err;
467 }
468 
469 static const struct got_error *
470 report_progress(got_pack_progress_cb progress_cb, void *progress_arg,
471     struct got_ratelimit *rl, int ncolored, int nfound, int ntrees,
472     off_t packfile_size, int ncommits, int nobj_total, int obj_deltify,
473     int nobj_written)
474 {
475 	const struct got_error *err;
476 	int elapsed;
477 
478 	if (progress_cb == NULL)
479 		return NULL;
480 
481 	err = got_ratelimit_check(&elapsed, rl);
482 	if (err || !elapsed)
483 		return err;
484 
485 	return progress_cb(progress_arg, ncolored, nfound, ntrees,
486 	    packfile_size, ncommits, nobj_total, obj_deltify, nobj_written);
487 }
488 
489 static const struct got_error *
490 add_meta(struct got_pack_meta *m, struct got_pack_metavec *v)
491 {
492 	if (v->nmeta == v->metasz){
493 		size_t newsize = 2 * v->metasz;
494 		struct got_pack_meta **new;
495 		new = reallocarray(v->meta, newsize, sizeof(*new));
496 		if (new == NULL)
497 			return got_error_from_errno("reallocarray");
498 		v->meta = new;
499 		v->metasz = newsize;
500 	}
501 
502 	v->meta[v->nmeta++] = m;
503 	return NULL;
504 }
505 
506 static const struct got_error *
507 find_pack_for_reuse(struct got_packidx **best_packidx,
508     struct got_repository *repo)
509 {
510 	const struct got_error *err = NULL;
511 	struct got_pathlist_entry *pe;
512 	const char *best_packidx_path = NULL;
513 	int nobj_max = 0;
514 
515 	*best_packidx = NULL;
516 
517 	TAILQ_FOREACH(pe, &repo->packidx_paths, entry) {
518 		const char *path_packidx = pe->path;
519 		struct got_packidx *packidx;
520 		int nobj;
521 
522 		err = got_repo_get_packidx(&packidx, path_packidx, repo);
523 		if (err)
524 			break;
525 
526 		nobj = be32toh(packidx->hdr.fanout_table[0xff]);
527 		if (nobj > nobj_max) {
528 			best_packidx_path = path_packidx;
529 			nobj_max = nobj;
530 		}
531 	}
532 
533 	if (best_packidx_path) {
534 		err = got_repo_get_packidx(best_packidx, best_packidx_path,
535 		    repo);
536 	}
537 
538 	return err;
539 }
540 
541 struct send_id_arg {
542 	struct imsgbuf *ibuf;
543 	struct got_object_id *ids[GOT_IMSG_OBJ_ID_LIST_MAX_NIDS];
544 	size_t nids;
545 };
546 
547 static const struct got_error *
548 send_id(struct got_object_id *id, void *data, void *arg)
549 {
550 	const struct got_error *err = NULL;
551 	struct send_id_arg *a = arg;
552 
553 	a->ids[a->nids++] = id;
554 
555 	if (a->nids >= GOT_IMSG_OBJ_ID_LIST_MAX_NIDS) {
556 		err = got_privsep_send_object_idlist(a->ibuf, a->ids, a->nids);
557 		if (err)
558 			return err;
559 		a->nids = 0;
560 	}
561 
562 	return NULL;
563 }
564 
565 static const struct got_error *
566 send_idset(struct imsgbuf *ibuf, struct got_object_idset *idset)
567 {
568 	const struct got_error *err;
569 	struct send_id_arg sia;
570 
571 	memset(&sia, 0, sizeof(sia));
572 	sia.ibuf = ibuf;
573 	err = got_object_idset_for_each(idset, send_id, &sia);
574 	if (err)
575 		return err;
576 
577 	if (sia.nids > 0) {
578 		err = got_privsep_send_object_idlist(ibuf, sia.ids, sia.nids);
579 		if (err)
580 			return err;
581 	}
582 
583 	return got_privsep_send_object_idlist_done(ibuf);
584 }
585 
586 
587 static const struct got_error *
588 recv_reused_delta(struct got_imsg_reused_delta *delta,
589     struct got_object_idset *idset, struct got_pack_metavec *v)
590 {
591 	struct got_pack_meta *m, *base;
592 
593 	if (delta->delta_offset + delta->delta_size < delta->delta_offset ||
594 	    delta->delta_offset +
595 	    delta->delta_compressed_size < delta->delta_offset)
596 		return got_error(GOT_ERR_BAD_PACKFILE);
597 
598 	m = got_object_idset_get(idset, &delta->id);
599 	if (m == NULL)
600 		return got_error(GOT_ERR_NO_OBJ);
601 
602 	base = got_object_idset_get(idset, &delta->base_id);
603 	if (base == NULL)
604 		return got_error(GOT_ERR_NO_OBJ);
605 
606 	m->delta_len = delta->delta_size;
607 	m->delta_compressed_len = delta->delta_compressed_size;
608 	m->delta_offset = delta->delta_out_offset;
609 	m->prev = base;
610 	m->size = delta->result_size;
611 	m->reused_delta_offset = delta->delta_offset;
612 	m->base_obj_id = got_object_id_dup(&delta->base_id);
613 	if (m->base_obj_id == NULL)
614 		return got_error_from_errno("got_object_id_dup");
615 
616 	return add_meta(m, v);
617 }
618 
619 static const struct got_error *
620 cache_pack_for_packidx(struct got_pack **pack, struct got_packidx *packidx,
621     struct got_repository *repo)
622 {
623 	const struct got_error *err;
624 	char *path_packfile = NULL;
625 
626 	err = got_packidx_get_packfile_path(&path_packfile,
627 	    packidx->path_packidx);
628 	if (err)
629 		return err;
630 
631 	*pack = got_repo_get_cached_pack(repo, path_packfile);
632 	if (*pack == NULL) {
633 		err = got_repo_cache_pack(pack, repo, path_packfile, packidx);
634 		if (err)
635 			goto done;
636 	}
637 	if ((*pack)->privsep_child == NULL) {
638 		err = got_pack_start_privsep_child(*pack, packidx);
639 		if (err)
640 			goto done;
641 	}
642 done:
643 	free(path_packfile);
644 	return err;
645 }
646 
647 static const struct got_error *
648 prepare_delta_reuse(struct got_pack *pack, struct got_packidx *packidx,
649     int delta_outfd, struct got_repository *repo)
650 {
651 	const struct got_error *err = NULL;
652 
653 	if (!pack->child_has_delta_outfd) {
654 		int outfd_child;
655 		outfd_child = dup(delta_outfd);
656 		if (outfd_child == -1) {
657 			err = got_error_from_errno("dup");
658 			goto done;
659 		}
660 		err = got_privsep_send_raw_delta_outfd(
661 		    pack->privsep_child->ibuf, outfd_child);
662 		if (err)
663 			goto done;
664 		pack->child_has_delta_outfd = 1;
665 	}
666 
667 	err = got_privsep_send_delta_reuse_req(pack->privsep_child->ibuf);
668 done:
669 	return err;
670 }
671 
672 
673 static const struct got_error *
674 search_deltas(struct got_pack_metavec *v, struct got_object_idset *idset,
675     int delta_cache_fd, int ncolored, int nfound, int ntrees, int ncommits,
676     struct got_repository *repo,
677     got_pack_progress_cb progress_cb, void *progress_arg,
678     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
679 {
680 	const struct got_error *err = NULL;
681 	struct got_packidx *packidx;
682 	struct got_pack *pack;
683 	struct got_imsg_reused_delta deltas[GOT_IMSG_REUSED_DELTAS_MAX_NDELTAS];
684 	size_t ndeltas, i;
685 
686 	err = find_pack_for_reuse(&packidx, repo);
687 	if (err)
688 		return err;
689 
690 	if (packidx == NULL)
691 		return NULL;
692 
693 	err = cache_pack_for_packidx(&pack, packidx, repo);
694 	if (err)
695 		return err;
696 
697 	err = prepare_delta_reuse(pack, packidx, delta_cache_fd, repo);
698 	if (err)
699 		return err;
700 
701 	err = send_idset(pack->privsep_child->ibuf, idset);
702 	if (err)
703 		return err;
704 
705 	for (;;) {
706 		int done = 0;
707 
708 		if (cancel_cb) {
709 			err = (*cancel_cb)(cancel_arg);
710 			if (err)
711 				break;
712 		}
713 
714 		err = got_privsep_recv_reused_deltas(&done, deltas, &ndeltas,
715 		    pack->privsep_child->ibuf);
716 		if (err || done)
717 			break;
718 
719 		for (i = 0; i < ndeltas; i++) {
720 			struct got_imsg_reused_delta *delta = &deltas[i];
721 			err = recv_reused_delta(delta, idset, v);
722 			if (err)
723 				goto done;
724 		}
725 
726 		err = report_progress(progress_cb, progress_arg, rl,
727 		    ncolored, nfound, ntrees, 0L, ncommits,
728 		    got_object_idset_num_elements(idset), v->nmeta, 0);
729 		if (err)
730 			break;
731 	}
732 done:
733 	return err;
734 }
735 
736 static const struct got_error *
737 pick_deltas(struct got_pack_meta **meta, int nmeta, int ncolored,
738     int nfound, int ntrees, int ncommits, int nreused, FILE *delta_cache,
739     struct got_repository *repo,
740     got_pack_progress_cb progress_cb, void *progress_arg,
741     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
742 {
743 	const struct got_error *err = NULL;
744 	struct got_pack_meta *m = NULL, *base = NULL;
745 	struct got_raw_object *raw = NULL, *base_raw = NULL;
746 	struct got_delta_instruction *deltas = NULL, *best_deltas = NULL;
747 	int i, j, ndeltas, best_ndeltas;
748 	off_t size, best_size;
749 	const int max_base_candidates = 3;
750 	size_t delta_memsize = 0;
751 	const size_t max_delta_memsize = 4 * GOT_DELTA_RESULT_SIZE_CACHED_MAX;
752 	int outfd = -1;
753 	uint32_t delta_seed;
754 
755 	delta_seed = arc4random();
756 
757 	qsort(meta, nmeta, sizeof(struct got_pack_meta *), delta_order_cmp);
758 	for (i = 0; i < nmeta; i++) {
759 		if (cancel_cb) {
760 			err = (*cancel_cb)(cancel_arg);
761 			if (err)
762 				break;
763 		}
764 		err = report_progress(progress_cb, progress_arg, rl,
765 		    ncolored, nfound, ntrees, 0L, ncommits, nreused + nmeta,
766 		    nreused + i, 0);
767 		if (err)
768 			goto done;
769 		m = meta[i];
770 
771 		if (m->obj_type == GOT_OBJ_TYPE_COMMIT ||
772 		    m->obj_type == GOT_OBJ_TYPE_TAG)
773 			continue;
774 
775 		err = got_object_raw_open(&raw, &outfd, repo, &m->id);
776 		if (err)
777 			goto done;
778 		m->size = raw->size;
779 
780 		if (raw->f == NULL) {
781 			err = got_deltify_init_mem(&m->dtab, raw->data,
782 			    raw->hdrlen, raw->size + raw->hdrlen, delta_seed);
783 		} else {
784 			err = got_deltify_init(&m->dtab, raw->f, raw->hdrlen,
785 			    raw->size + raw->hdrlen, delta_seed);
786 		}
787 		if (err)
788 			goto done;
789 
790 		if (i > max_base_candidates) {
791 			struct got_pack_meta *n = NULL;
792 			n = meta[i - (max_base_candidates + 1)];
793 			got_deltify_free(n->dtab);
794 			n->dtab = NULL;
795 		}
796 
797 		best_size = raw->size;
798 		best_ndeltas = 0;
799 		for (j = MAX(0, i - max_base_candidates); j < i; j++) {
800 			if (cancel_cb) {
801 				err = (*cancel_cb)(cancel_arg);
802 				if (err)
803 					goto done;
804 			}
805 			base = meta[j];
806 			/* long chains make unpacking slow, avoid such bases */
807 			if (base->nchain >= 128 ||
808 			    base->obj_type != m->obj_type)
809 				continue;
810 
811 			err = got_object_raw_open(&base_raw, &outfd, repo,
812 			    &base->id);
813 			if (err)
814 				goto done;
815 
816 			if (raw->f == NULL && base_raw->f == NULL) {
817 				err = got_deltify_mem_mem(&deltas, &ndeltas,
818 				    raw->data, raw->hdrlen,
819 				    raw->size + raw->hdrlen, delta_seed,
820 				    base->dtab, base_raw->data,
821 				    base_raw->hdrlen,
822 				    base_raw->size + base_raw->hdrlen);
823 			} else if (raw->f == NULL) {
824 				err = got_deltify_mem_file(&deltas, &ndeltas,
825 				    raw->data, raw->hdrlen,
826 				    raw->size + raw->hdrlen, delta_seed,
827 				    base->dtab, base_raw->f,
828 				    base_raw->hdrlen,
829 				    base_raw->size + base_raw->hdrlen);
830 			} else if (base_raw->f == NULL) {
831 				err = got_deltify_file_mem(&deltas, &ndeltas,
832 				    raw->f, raw->hdrlen,
833 				    raw->size + raw->hdrlen, delta_seed,
834 				    base->dtab, base_raw->data,
835 				    base_raw->hdrlen,
836 				    base_raw->size + base_raw->hdrlen);
837 			} else {
838 				err = got_deltify(&deltas, &ndeltas,
839 				    raw->f, raw->hdrlen,
840 				    raw->size + raw->hdrlen, delta_seed,
841 				    base->dtab, base_raw->f, base_raw->hdrlen,
842 				    base_raw->size + base_raw->hdrlen);
843 			}
844 			got_object_raw_close(base_raw);
845 			base_raw = NULL;
846 			if (err)
847 				goto done;
848 
849 			size = delta_size(deltas, ndeltas);
850 			if (size + 32 < best_size){
851 				/*
852 				 * if we already picked a best delta,
853 				 * replace it.
854 				 */
855 				best_size = size;
856 				free(best_deltas);
857 				best_deltas = deltas;
858 				best_ndeltas = ndeltas;
859 				deltas = NULL;
860 				m->nchain = base->nchain + 1;
861 				m->prev = base;
862 				m->head = base->head;
863 				if (m->head == NULL)
864 					m->head = base;
865 			} else {
866 				free(deltas);
867 				deltas = NULL;
868 				ndeltas = 0;
869 			}
870 		}
871 
872 		if (best_ndeltas > 0) {
873 			if (best_size <= GOT_DELTA_RESULT_SIZE_CACHED_MAX &&
874 			    delta_memsize + best_size <= max_delta_memsize) {
875 				delta_memsize += best_size;
876 				err = encode_delta_in_mem(m, raw, best_deltas,
877 				    best_ndeltas, best_size, m->prev->size);
878 			} else {
879 				m->delta_offset = ftello(delta_cache);
880 				err = encode_delta(m, raw, best_deltas,
881 				    best_ndeltas, m->prev->size, delta_cache);
882 			}
883 			free(best_deltas);
884 			best_deltas = NULL;
885 			best_ndeltas = 0;
886 			if (err)
887 				goto done;
888 		}
889 
890 		got_object_raw_close(raw);
891 		raw = NULL;
892 	}
893 done:
894 	for (i = MAX(0, nmeta - max_base_candidates); i < nmeta; i++) {
895 		got_deltify_free(meta[i]->dtab);
896 		meta[i]->dtab = NULL;
897 	}
898 	if (raw)
899 		got_object_raw_close(raw);
900 	if (base_raw)
901 		got_object_raw_close(base_raw);
902 	if (outfd != -1 && close(outfd) == -1 && err == NULL)
903 		err = got_error_from_errno("close");
904 	free(deltas);
905 	free(best_deltas);
906 	return err;
907 }
908 
909 static const struct got_error *
910 search_packidx(int *found, struct got_object_id *id,
911     struct got_repository *repo)
912 {
913 	const struct got_error *err = NULL;
914 	struct got_packidx *packidx = NULL;
915 	int idx;
916 
917 	*found = 0;
918 
919 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
920 	if (err == NULL)
921 		*found = 1; /* object is already packed */
922 	else if (err->code == GOT_ERR_NO_OBJ)
923 		err = NULL;
924 	return err;
925 }
926 
927 static const struct got_error *
928 add_object(int want_meta, struct got_object_idset *idset,
929     struct got_object_id *id, const char *path, int obj_type,
930     time_t mtime, uint32_t seed, int loose_obj_only,
931     struct got_repository *repo, int *ncolored, int *nfound, int *ntrees,
932     got_pack_progress_cb progress_cb, void *progress_arg,
933     struct got_ratelimit *rl)
934 {
935 	const struct got_error *err;
936 	struct got_pack_meta *m = NULL;
937 
938 	if (loose_obj_only) {
939 		int is_packed;
940 		err = search_packidx(&is_packed, id, repo);
941 		if (err)
942 			return err;
943 		if (is_packed && want_meta)
944 			return NULL;
945 	}
946 
947 	if (want_meta) {
948 		err = alloc_meta(&m, id, path, obj_type, mtime, seed);
949 		if (err)
950 			return err;
951 
952 		(*nfound)++;
953 		err = report_progress(progress_cb, progress_arg, rl,
954 		    *ncolored, *nfound, *ntrees, 0L, 0, 0, 0, 0);
955 		if (err) {
956 			clear_meta(m);
957 			free(m);
958 			return err;
959 		}
960 	}
961 
962 	err = got_object_idset_add(idset, id, m);
963 	if (err) {
964 		clear_meta(m);
965 		free(m);
966 	}
967 	return err;
968 }
969 
970 static const struct got_error *
971 load_tree_entries(struct got_object_id_queue *ids, int want_meta,
972     struct got_object_idset *idset, struct got_object_idset *idset_exclude,
973     struct got_tree_object *tree,
974     const char *dpath, time_t mtime, uint32_t seed, struct got_repository *repo,
975     int loose_obj_only, int *ncolored, int *nfound, int *ntrees,
976     got_pack_progress_cb progress_cb, void *progress_arg,
977     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
978 {
979 	const struct got_error *err;
980 	char *p = NULL;
981 	int i;
982 
983 	(*ntrees)++;
984 	err = report_progress(progress_cb, progress_arg, rl,
985 	    *ncolored, *nfound, *ntrees, 0L, 0, 0, 0, 0);
986 	if (err)
987 		return err;
988 
989 	for (i = 0; i < got_object_tree_get_nentries(tree); i++) {
990 		struct got_tree_entry *e = got_object_tree_get_entry(tree, i);
991 		struct got_object_id *id = got_tree_entry_get_id(e);
992 		mode_t mode = got_tree_entry_get_mode(e);
993 
994 		if (cancel_cb) {
995 			err = (*cancel_cb)(cancel_arg);
996 			if (err)
997 				break;
998 		}
999 
1000 		if (got_object_tree_entry_is_submodule(e) ||
1001 		    got_object_idset_contains(idset, id) ||
1002 		    got_object_idset_contains(idset_exclude, id))
1003 			continue;
1004 
1005 		/*
1006 		 * If got-read-pack is crawling trees for us then
1007 		 * we are only here to collect blob IDs.
1008 		 */
1009 		if (ids == NULL && S_ISDIR(mode))
1010 			continue;
1011 
1012 		if (asprintf(&p, "%s%s%s", dpath,
1013 		    got_path_is_root_dir(dpath) ? "" : "/",
1014 		    got_tree_entry_get_name(e)) == -1) {
1015 			err = got_error_from_errno("asprintf");
1016 			break;
1017 		}
1018 
1019 		if (S_ISDIR(mode)) {
1020 			struct got_object_qid *qid;
1021 			err = got_object_qid_alloc(&qid, id);
1022 			if (err)
1023 				break;
1024 			qid->data = p;
1025 			p = NULL;
1026 			STAILQ_INSERT_TAIL(ids, qid, entry);
1027 		} else if (S_ISREG(mode) || S_ISLNK(mode)) {
1028 			err = add_object(want_meta,
1029 			    want_meta ? idset : idset_exclude, id, p,
1030 			    GOT_OBJ_TYPE_BLOB, mtime, seed, loose_obj_only,
1031 			    repo, ncolored, nfound, ntrees,
1032 			    progress_cb, progress_arg, rl);
1033 			if (err)
1034 				break;
1035 			free(p);
1036 			p = NULL;
1037 		} else {
1038 			free(p);
1039 			p = NULL;
1040 		}
1041 	}
1042 
1043 	free(p);
1044 	return err;
1045 }
1046 
1047 static const struct got_error *
1048 load_tree(int want_meta, struct got_object_idset *idset,
1049     struct got_object_idset *idset_exclude,
1050     struct got_object_id *tree_id, const char *dpath, time_t mtime,
1051     uint32_t seed, struct got_repository *repo, int loose_obj_only,
1052     int *ncolored, int *nfound, int *ntrees,
1053     got_pack_progress_cb progress_cb, void *progress_arg,
1054     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1055 {
1056 	const struct got_error *err = NULL;
1057 	struct got_object_id_queue tree_ids;
1058 	struct got_object_qid *qid;
1059 	struct got_tree_object *tree = NULL;
1060 
1061 	if (got_object_idset_contains(idset, tree_id) ||
1062 	    got_object_idset_contains(idset_exclude, tree_id))
1063 		return NULL;
1064 
1065 	err = got_object_qid_alloc(&qid, tree_id);
1066 	if (err)
1067 		return err;
1068 	qid->data = strdup(dpath);
1069 	if (qid->data == NULL) {
1070 		err = got_error_from_errno("strdup");
1071 		got_object_qid_free(qid);
1072 		return err;
1073 	}
1074 
1075 	STAILQ_INIT(&tree_ids);
1076 	STAILQ_INSERT_TAIL(&tree_ids, qid, entry);
1077 
1078 	while (!STAILQ_EMPTY(&tree_ids)) {
1079 		const char *path;
1080 		if (cancel_cb) {
1081 			err = (*cancel_cb)(cancel_arg);
1082 			if (err)
1083 				break;
1084 		}
1085 
1086 		qid = STAILQ_FIRST(&tree_ids);
1087 		STAILQ_REMOVE_HEAD(&tree_ids, entry);
1088 		path = qid->data;
1089 
1090 		if (got_object_idset_contains(idset, &qid->id) ||
1091 		    got_object_idset_contains(idset_exclude, &qid->id)) {
1092 			free(qid->data);
1093 			got_object_qid_free(qid);
1094 			continue;
1095 		}
1096 
1097 		err = add_object(want_meta, want_meta ? idset : idset_exclude,
1098 		    &qid->id, path, GOT_OBJ_TYPE_TREE,
1099 		    mtime, seed, loose_obj_only, repo,
1100 		    ncolored, nfound, ntrees, progress_cb, progress_arg, rl);
1101 		if (err) {
1102 			free(qid->data);
1103 			got_object_qid_free(qid);
1104 			break;
1105 		}
1106 
1107 		err = got_object_open_as_tree(&tree, repo, &qid->id);
1108 		if (err) {
1109 			free(qid->data);
1110 			got_object_qid_free(qid);
1111 			break;
1112 		}
1113 
1114 		err = load_tree_entries(&tree_ids, want_meta, idset,
1115 		    idset_exclude, tree, path, mtime, seed, repo,
1116 		    loose_obj_only, ncolored, nfound, ntrees,
1117 		    progress_cb, progress_arg, rl,
1118 		    cancel_cb, cancel_arg);
1119 		free(qid->data);
1120 		got_object_qid_free(qid);
1121 		if (err)
1122 			break;
1123 
1124 		got_object_tree_close(tree);
1125 		tree = NULL;
1126 	}
1127 
1128 	STAILQ_FOREACH(qid, &tree_ids, entry)
1129 		free(qid->data);
1130 	got_object_id_queue_free(&tree_ids);
1131 	if (tree)
1132 		got_object_tree_close(tree);
1133 	return err;
1134 }
1135 
1136 static const struct got_error *
1137 load_commit(int want_meta, struct got_object_idset *idset,
1138     struct got_object_idset *idset_exclude,
1139     struct got_object_id *id, struct got_repository *repo, uint32_t seed,
1140     int loose_obj_only, int *ncolored, int *nfound, int *ntrees,
1141     got_pack_progress_cb progress_cb, void *progress_arg,
1142     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1143 {
1144 	const struct got_error *err;
1145 	struct got_commit_object *commit;
1146 
1147 	if (got_object_idset_contains(idset, id) ||
1148 	    got_object_idset_contains(idset_exclude, id))
1149 		return NULL;
1150 
1151 	if (loose_obj_only) {
1152 		int is_packed;
1153 		err = search_packidx(&is_packed, id, repo);
1154 		if (err)
1155 			return err;
1156 		if (is_packed && want_meta)
1157 			return NULL;
1158 	}
1159 
1160 	err = got_object_open_as_commit(&commit, repo, id);
1161 	if (err)
1162 		return err;
1163 
1164 	err = add_object(want_meta, want_meta ? idset : idset_exclude,
1165 	    id, "", GOT_OBJ_TYPE_COMMIT,
1166 	    got_object_commit_get_committer_time(commit), seed,
1167 	    loose_obj_only, repo,
1168 	    ncolored, nfound, ntrees, progress_cb, progress_arg, rl);
1169 	if (err)
1170 		goto done;
1171 
1172 	err = load_tree(want_meta, idset, idset_exclude,
1173 	    got_object_commit_get_tree_id(commit),
1174 	    "", got_object_commit_get_committer_time(commit), seed,
1175 	    repo, loose_obj_only, ncolored, nfound, ntrees,
1176 	    progress_cb, progress_arg, rl, cancel_cb, cancel_arg);
1177 done:
1178 	got_object_commit_close(commit);
1179 	return err;
1180 }
1181 
1182 static const struct got_error *
1183 load_tag(int want_meta, struct got_object_idset *idset,
1184     struct got_object_idset *idset_exclude,
1185     struct got_object_id *id, struct got_repository *repo, uint32_t seed,
1186     int loose_obj_only, int *ncolored, int *nfound, int *ntrees,
1187     got_pack_progress_cb progress_cb, void *progress_arg,
1188     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1189 {
1190 	const struct got_error *err;
1191 	struct got_tag_object *tag = NULL;
1192 
1193 	if (got_object_idset_contains(idset, id) ||
1194 	    got_object_idset_contains(idset_exclude, id))
1195 		return NULL;
1196 
1197 	if (loose_obj_only) {
1198 		int is_packed;
1199 		err = search_packidx(&is_packed, id, repo);
1200 		if (err)
1201 			return err;
1202 		if (is_packed && want_meta)
1203 			return NULL;
1204 	}
1205 
1206 	err = got_object_open_as_tag(&tag, repo, id);
1207 	if (err)
1208 		return err;
1209 
1210 	err = add_object(want_meta, want_meta ? idset : idset_exclude,
1211 	    id, "", GOT_OBJ_TYPE_TAG,
1212 	    got_object_tag_get_tagger_time(tag), seed, loose_obj_only, repo,
1213 	    ncolored, nfound, ntrees, progress_cb, progress_arg, rl);
1214 	if (err)
1215 		goto done;
1216 
1217 	switch (got_object_tag_get_object_type(tag)) {
1218 	case GOT_OBJ_TYPE_COMMIT:
1219 		err = load_commit(want_meta, idset, idset_exclude,
1220 		    got_object_tag_get_object_id(tag), repo, seed,
1221 		    loose_obj_only, ncolored, nfound, ntrees,
1222 		    progress_cb, progress_arg, rl, cancel_cb, cancel_arg);
1223 		break;
1224 	case GOT_OBJ_TYPE_TREE:
1225 		err = load_tree(want_meta, idset, idset_exclude,
1226 		    got_object_tag_get_object_id(tag), "",
1227 		    got_object_tag_get_tagger_time(tag), seed, repo,
1228 		    loose_obj_only, ncolored, nfound, ntrees,
1229 		    progress_cb, progress_arg, rl, cancel_cb, cancel_arg);
1230 		break;
1231 	default:
1232 		break;
1233 	}
1234 
1235 done:
1236 	got_object_tag_close(tag);
1237 	return err;
1238 }
1239 
1240 enum findtwixt_color {
1241 	COLOR_KEEP = 0,
1242 	COLOR_DROP,
1243 	COLOR_SKIP,
1244 	COLOR_MAX,
1245 };
1246 
1247 static const struct got_error *
1248 paint_commit(struct got_object_qid *qid, intptr_t color)
1249 {
1250 	if (color < 0 || color >= COLOR_MAX)
1251 		return got_error(GOT_ERR_RANGE);
1252 
1253 	qid->data = (void *)color;
1254 	return NULL;
1255 }
1256 
1257 static const struct got_error *
1258 queue_commit_id(struct got_object_id_queue *ids, struct got_object_id *id,
1259     intptr_t color, struct got_repository *repo)
1260 {
1261 	const struct got_error *err;
1262 	struct got_object_qid *qid;
1263 
1264 	err = got_object_qid_alloc(&qid, id);
1265 	if (err)
1266 		return err;
1267 
1268 	STAILQ_INSERT_TAIL(ids, qid, entry);
1269 	return paint_commit(qid, color);
1270 }
1271 
1272 struct append_id_arg {
1273 	struct got_object_id **array;
1274 	int idx;
1275 	struct got_object_idset *drop;
1276 	struct got_object_idset *skip;
1277 };
1278 
1279 static const struct got_error *
1280 append_id(struct got_object_id *id, void *data, void *arg)
1281 {
1282 	struct append_id_arg *a = arg;
1283 
1284 	if (got_object_idset_contains(a->skip, id) ||
1285 	    got_object_idset_contains(a->drop, id))
1286 		return NULL;
1287 
1288 	a->array[++a->idx] = got_object_id_dup(id);
1289 	if (a->array[a->idx] == NULL)
1290 		return got_error_from_errno("got_object_id_dup");
1291 
1292 	return NULL;
1293 }
1294 
1295 static const struct got_error *
1296 queue_commit_or_tag_id(struct got_object_id *id, intptr_t color,
1297     struct got_object_id_queue *ids, struct got_repository *repo)
1298 {
1299 	const struct got_error *err;
1300 	struct got_tag_object *tag = NULL;
1301 	int obj_type;
1302 
1303 	err = got_object_get_type(&obj_type, repo, id);
1304 	if (err)
1305 		return err;
1306 
1307 	if (obj_type == GOT_OBJ_TYPE_TAG) {
1308 		err = got_object_open_as_tag(&tag, repo, id);
1309 		if (err)
1310 			return err;
1311 		obj_type = got_object_tag_get_object_type(tag);
1312 		id = got_object_tag_get_object_id(tag);
1313 	}
1314 
1315 	if (obj_type == GOT_OBJ_TYPE_COMMIT) {
1316 		err = queue_commit_id(ids, id, color, repo);
1317 		if (err)
1318 			goto done;
1319 	}
1320 done:
1321 	if (tag)
1322 		got_object_tag_close(tag);
1323 	return err;
1324 }
1325 
1326 struct recv_painted_commit_arg {
1327 	int *ncolored;
1328 	int *nqueued;
1329 	int *nskip;
1330 	struct got_object_id_queue *ids;
1331 	struct got_object_idset *keep;
1332 	struct got_object_idset *drop;
1333 	struct got_object_idset *skip;
1334 	got_pack_progress_cb progress_cb;
1335 	void *progress_arg;
1336 	struct got_ratelimit *rl;
1337 	got_cancel_cb cancel_cb;
1338 	void *cancel_arg;
1339 };
1340 
1341 static const struct got_error *
1342 recv_painted_commit(void *arg, struct got_object_id *id, intptr_t color)
1343 {
1344 	const struct got_error *err = NULL;
1345 	struct recv_painted_commit_arg *a = arg;
1346 	struct got_object_qid *qid, *tmp;
1347 
1348 	if (a->cancel_cb) {
1349 		err = a->cancel_cb(a->cancel_arg);
1350 		if (err)
1351 			return err;
1352 	}
1353 
1354 	switch (color) {
1355 	case COLOR_KEEP:
1356 		err = got_object_idset_add(a->keep, id, NULL);
1357 		if (err)
1358 			return err;
1359 		(*a->ncolored)++;
1360 		break;
1361 	case COLOR_DROP:
1362 		err = got_object_idset_add(a->drop, id, NULL);
1363 		if (err)
1364 			return err;
1365 		(*a->ncolored)++;
1366 		break;
1367 	case COLOR_SKIP:
1368 		err = got_object_idset_add(a->skip, id, NULL);
1369 		if (err)
1370 			return err;
1371 		break;
1372 	default:
1373 		/* should not happen */
1374 		return got_error_fmt(GOT_ERR_NOT_IMPL,
1375 		    "%s invalid commit color %"PRIdPTR, __func__, color);
1376 	}
1377 
1378 	STAILQ_FOREACH_SAFE(qid, a->ids, entry, tmp) {
1379 		if (got_object_id_cmp(&qid->id, id) != 0)
1380 			continue;
1381 		STAILQ_REMOVE(a->ids, qid, got_object_qid, entry);
1382 		color = (intptr_t)qid->data;
1383 		got_object_qid_free(qid);
1384 		(*a->nqueued)--;
1385 		if (color == COLOR_SKIP)
1386 			(*a->nskip)--;
1387 		break;
1388 	}
1389 
1390 	return report_progress(a->progress_cb, a->progress_arg, a->rl,
1391 	    *a->ncolored, 0, 0, 0L, 0, 0, 0, 0);
1392 }
1393 
1394 static const struct got_error *
1395 paint_packed_commits(struct got_pack *pack, struct got_object_id *id,
1396     int idx, intptr_t color, int *ncolored, int *nqueued, int *nskip,
1397     struct got_object_id_queue *ids,
1398     struct got_object_idset *keep, struct got_object_idset *drop,
1399     struct got_object_idset *skip, struct got_repository *repo,
1400     got_pack_progress_cb progress_cb, void *progress_arg,
1401     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1402 {
1403 	const struct got_error *err = NULL;
1404 	struct got_object_id_queue next_ids;
1405 	struct got_object_qid *qid, *tmp;
1406 	struct recv_painted_commit_arg arg;
1407 
1408 	STAILQ_INIT(&next_ids);
1409 
1410 	err = got_privsep_send_painting_request(pack->privsep_child->ibuf,
1411 	    idx, id, color);
1412 	if (err)
1413 		return err;
1414 
1415 	arg.ncolored = ncolored;
1416 	arg.nqueued = nqueued;
1417 	arg.nskip = nskip;
1418 	arg.ids = ids;
1419 	arg.keep = keep;
1420 	arg.drop = drop;
1421 	arg.skip = skip;
1422 	arg.progress_cb = progress_cb;
1423 	arg.progress_arg = progress_arg;
1424 	arg.rl = rl;
1425 	arg.cancel_cb = cancel_cb;
1426 	arg.cancel_arg = cancel_arg;
1427 	err = got_privsep_recv_painted_commits(&next_ids,
1428 	    recv_painted_commit, &arg, pack->privsep_child->ibuf);
1429 	if (err)
1430 		return err;
1431 
1432 	STAILQ_FOREACH_SAFE(qid, &next_ids, entry, tmp) {
1433 		struct got_object_qid *old_id;
1434 		intptr_t qcolor, ocolor;
1435 		STAILQ_FOREACH(old_id, ids, entry) {
1436 			if (got_object_id_cmp(&qid->id, &old_id->id))
1437 				continue;
1438 			qcolor = (intptr_t)qid->data;
1439 			ocolor = (intptr_t)old_id->data;
1440 			STAILQ_REMOVE(&next_ids, qid, got_object_qid, entry);
1441 			got_object_qid_free(qid);
1442 			qid = NULL;
1443 			if (qcolor != ocolor) {
1444 				paint_commit(old_id, qcolor);
1445 				if (ocolor == COLOR_SKIP)
1446 					(*nskip)--;
1447 				else if (qcolor == COLOR_SKIP)
1448 					(*nskip)++;
1449 			}
1450 			break;
1451 		}
1452 	}
1453 	while (!STAILQ_EMPTY(&next_ids)) {
1454 		qid = STAILQ_FIRST(&next_ids);
1455 		STAILQ_REMOVE_HEAD(&next_ids, entry);
1456 		paint_commit(qid, color);
1457 		STAILQ_INSERT_TAIL(ids, qid, entry);
1458 		(*nqueued)++;
1459 		if (color == COLOR_SKIP)
1460 			(*nskip)++;
1461 	}
1462 
1463 	return err;
1464 }
1465 
1466 static const struct got_error *
1467 find_pack_for_commit_painting(struct got_packidx **best_packidx,
1468     struct got_object_id_queue *ids, int nids, struct got_repository *repo)
1469 {
1470 	const struct got_error *err = NULL;
1471 	struct got_pathlist_entry *pe;
1472 	const char *best_packidx_path = NULL;
1473 	int nobj_max = 0;
1474 	int ncommits_max = 0;
1475 
1476 	*best_packidx = NULL;
1477 
1478 	/*
1479 	 * Find the largest pack which contains at least some of the
1480 	 * commits we are interested in.
1481 	 */
1482 	TAILQ_FOREACH(pe, &repo->packidx_paths, entry) {
1483 		const char *path_packidx = pe->path;
1484 		struct got_packidx *packidx;
1485 		int nobj, idx, ncommits = 0;
1486 		struct got_object_qid *qid;
1487 
1488 		err = got_repo_get_packidx(&packidx, path_packidx, repo);
1489 		if (err)
1490 			break;
1491 
1492 		nobj = be32toh(packidx->hdr.fanout_table[0xff]);
1493 		if (nobj <= nobj_max)
1494 			continue;
1495 
1496 		STAILQ_FOREACH(qid, ids, entry) {
1497 			idx = got_packidx_get_object_idx(packidx, &qid->id);
1498 			if (idx != -1)
1499 				ncommits++;
1500 		}
1501 		if (ncommits > ncommits_max) {
1502 			best_packidx_path = path_packidx;
1503 			nobj_max = nobj;
1504 			ncommits_max = ncommits;
1505 		}
1506 	}
1507 
1508 	if (best_packidx_path && err == NULL) {
1509 		err = got_repo_get_packidx(best_packidx, best_packidx_path,
1510 		    repo);
1511 	}
1512 
1513 	return err;
1514 }
1515 
1516 static const struct got_error *
1517 paint_commits(int *ncolored, struct got_object_id_queue *ids, int nids,
1518     struct got_object_idset *keep, struct got_object_idset *drop,
1519     struct got_object_idset *skip, struct got_repository *repo,
1520     got_pack_progress_cb progress_cb, void *progress_arg,
1521     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1522 {
1523 	const struct got_error *err = NULL;
1524 	struct got_commit_object *commit = NULL;
1525 	struct got_packidx *packidx = NULL;
1526 	struct got_pack *pack = NULL;
1527 	const struct got_object_id_queue *parents;
1528 	struct got_object_qid *qid = NULL;
1529 	int nqueued = nids, nskip = 0;
1530 	int idx;
1531 
1532 	while (!STAILQ_EMPTY(ids) && nskip != nqueued) {
1533 		intptr_t color;
1534 
1535 		if (cancel_cb) {
1536 			err = cancel_cb(cancel_arg);
1537 			if (err)
1538 				break;
1539 		}
1540 
1541 		qid = STAILQ_FIRST(ids);
1542 		STAILQ_REMOVE_HEAD(ids, entry);
1543 		nqueued--;
1544 		color = (intptr_t)qid->data;
1545 		if (color == COLOR_SKIP)
1546 			nskip--;
1547 
1548 		if (got_object_idset_contains(skip, &qid->id)) {
1549 			got_object_qid_free(qid);
1550 			qid = NULL;
1551 			continue;
1552 		}
1553 		if (color == COLOR_KEEP &&
1554 		    got_object_idset_contains(keep, &qid->id)) {
1555 			got_object_qid_free(qid);
1556 			qid = NULL;
1557 			continue;
1558 		}
1559 		if (color == COLOR_DROP &&
1560 		    got_object_idset_contains(drop, &qid->id)) {
1561 			got_object_qid_free(qid);
1562 			qid = NULL;
1563 			continue;
1564 		}
1565 
1566 		/* Pinned pack may have moved to different cache slot. */
1567 		pack = got_repo_get_pinned_pack(repo);
1568 
1569 		if (packidx && pack) {
1570 			idx = got_packidx_get_object_idx(packidx, &qid->id);
1571 			if (idx != -1) {
1572 				err = paint_packed_commits(pack, &qid->id,
1573 				    idx, color, ncolored, &nqueued, &nskip,
1574 				    ids, keep, drop, skip, repo,
1575 				    progress_cb, progress_arg, rl,
1576 				    cancel_cb, cancel_arg);
1577 				if (err)
1578 					break;
1579 				got_object_qid_free(qid);
1580 				qid = NULL;
1581 				continue;
1582 			}
1583 		}
1584 
1585 		switch (color) {
1586 		case COLOR_KEEP:
1587 			if (got_object_idset_contains(drop, &qid->id)) {
1588 				err = paint_commit(qid, COLOR_SKIP);
1589 				if (err)
1590 					goto done;
1591 			} else
1592 				(*ncolored)++;
1593 			err = got_object_idset_add(keep, &qid->id, NULL);
1594 			if (err)
1595 				goto done;
1596 			break;
1597 		case COLOR_DROP:
1598 			if (got_object_idset_contains(keep, &qid->id)) {
1599 				err = paint_commit(qid, COLOR_SKIP);
1600 				if (err)
1601 					goto done;
1602 			} else
1603 				(*ncolored)++;
1604 			err = got_object_idset_add(drop, &qid->id, NULL);
1605 			if (err)
1606 				goto done;
1607 			break;
1608 		case COLOR_SKIP:
1609 			if (!got_object_idset_contains(skip, &qid->id)) {
1610 				err = got_object_idset_add(skip, &qid->id,
1611 				    NULL);
1612 				if (err)
1613 					goto done;
1614 			}
1615 			break;
1616 		default:
1617 			/* should not happen */
1618 			err = got_error_fmt(GOT_ERR_NOT_IMPL,
1619 			    "%s invalid commit color %"PRIdPTR, __func__,
1620 			    color);
1621 			goto done;
1622 		}
1623 
1624 		err = report_progress(progress_cb, progress_arg, rl,
1625 		    *ncolored, 0, 0, 0L, 0, 0, 0, 0);
1626 		if (err)
1627 			break;
1628 
1629 		err = got_object_open_as_commit(&commit, repo, &qid->id);
1630 		if (err)
1631 			break;
1632 
1633 		parents = got_object_commit_get_parent_ids(commit);
1634 		if (parents) {
1635 			struct got_object_qid *pid;
1636 			color = (intptr_t)qid->data;
1637 			STAILQ_FOREACH(pid, parents, entry) {
1638 				err = queue_commit_id(ids, &pid->id,
1639 				    color, repo);
1640 				if (err)
1641 					break;
1642 				nqueued++;
1643 				if (color == COLOR_SKIP)
1644 					nskip++;
1645 			}
1646 		}
1647 
1648 		if (pack == NULL && (commit->flags & GOT_COMMIT_FLAG_PACKED)) {
1649 			if (packidx == NULL) {
1650 				err = find_pack_for_commit_painting(&packidx,
1651 				    ids, nqueued, repo);
1652 				if (err)
1653 					goto done;
1654 			}
1655 			if (packidx != NULL) {
1656 				err = cache_pack_for_packidx(&pack, packidx,
1657 				    repo);
1658 				if (err)
1659 					goto done;
1660 				err = got_privsep_init_commit_painting(
1661 				    pack->privsep_child->ibuf);
1662 				if (err)
1663 					goto done;
1664 				err = send_idset(pack->privsep_child->ibuf,
1665 				    keep);
1666 				if (err)
1667 					goto done;
1668 				err = send_idset(pack->privsep_child->ibuf, drop);
1669 				if (err)
1670 					goto done;
1671 				err = send_idset(pack->privsep_child->ibuf, skip);
1672 				if (err)
1673 					goto done;
1674 				err = got_repo_pin_pack(repo, packidx, pack);
1675 				if (err)
1676 					goto done;
1677 			}
1678 		}
1679 
1680 		got_object_commit_close(commit);
1681 		commit = NULL;
1682 
1683 		got_object_qid_free(qid);
1684 		qid = NULL;
1685 	}
1686 done:
1687 	if (pack) {
1688 		const struct got_error *pack_err;
1689 		pack_err = got_privsep_send_painting_commits_done(
1690 		    pack->privsep_child->ibuf);
1691 		if (err == NULL)
1692 			err = pack_err;
1693 	}
1694 	if (commit)
1695 		got_object_commit_close(commit);
1696 	got_object_qid_free(qid);
1697 	got_repo_unpin_pack(repo);
1698 	return err;
1699 }
1700 
1701 static const struct got_error *
1702 findtwixt(struct got_object_id ***res, int *nres, int *ncolored,
1703     struct got_object_id **head, int nhead,
1704     struct got_object_id **tail, int ntail,
1705     struct got_repository *repo,
1706     got_pack_progress_cb progress_cb, void *progress_arg,
1707     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1708 {
1709 	const struct got_error *err = NULL;
1710 	struct got_object_id_queue ids;
1711 	struct got_object_idset *keep, *drop, *skip = NULL;
1712 	int i, nkeep;
1713 
1714 	STAILQ_INIT(&ids);
1715 	*res = NULL;
1716 	*nres = 0;
1717 	*ncolored = 0;
1718 
1719 	keep = got_object_idset_alloc();
1720 	if (keep == NULL)
1721 		return got_error_from_errno("got_object_idset_alloc");
1722 
1723 	drop = got_object_idset_alloc();
1724 	if (drop == NULL) {
1725 		err = got_error_from_errno("got_object_idset_alloc");
1726 		goto done;
1727 	}
1728 
1729 	skip = got_object_idset_alloc();
1730 	if (skip == NULL) {
1731 		err = got_error_from_errno("got_object_idset_alloc");
1732 		goto done;
1733 	}
1734 
1735 	for (i = 0; i < nhead; i++) {
1736 		struct got_object_id *id = head[i];
1737 		if (id == NULL)
1738 			continue;
1739 		err = queue_commit_or_tag_id(id, COLOR_KEEP, &ids, repo);
1740 		if (err)
1741 			goto done;
1742 	}
1743 
1744 	for (i = 0; i < ntail; i++) {
1745 		struct got_object_id *id = tail[i];
1746 		if (id == NULL)
1747 			continue;
1748 		err = queue_commit_or_tag_id(id, COLOR_DROP, &ids, repo);
1749 		if (err)
1750 			goto done;
1751 	}
1752 
1753 	err = paint_commits(ncolored, &ids, nhead + ntail,
1754 	    keep, drop, skip, repo, progress_cb, progress_arg, rl,
1755 	    cancel_cb, cancel_arg);
1756 	if (err)
1757 		goto done;
1758 
1759 	nkeep = got_object_idset_num_elements(keep);
1760 	if (nkeep > 0) {
1761 		struct append_id_arg arg;
1762 		arg.array = calloc(nkeep, sizeof(struct got_object_id *));
1763 		if (arg.array == NULL) {
1764 			err = got_error_from_errno("calloc");
1765 			goto done;
1766 		}
1767 		arg.idx = -1;
1768 		arg.skip = skip;
1769 		arg.drop = drop;
1770 		err = got_object_idset_for_each(keep, append_id, &arg);
1771 		if (err) {
1772 			free(arg.array);
1773 			goto done;
1774 		}
1775 		*res = arg.array;
1776 		*nres = arg.idx + 1;
1777 	}
1778 done:
1779 	got_object_idset_free(keep);
1780 	got_object_idset_free(drop);
1781 	if (skip)
1782 		got_object_idset_free(skip);
1783 	got_object_id_queue_free(&ids);
1784 	return err;
1785 }
1786 
1787 struct load_packed_obj_arg {
1788 	/* output parameters: */
1789 	struct got_object_id *id;
1790 	char *dpath;
1791 	time_t mtime;
1792 
1793 	/* input parameters: */
1794 	uint32_t seed;
1795 	int want_meta;
1796 	struct got_object_idset *idset;
1797 	struct got_object_idset *idset_exclude;
1798 	int loose_obj_only;
1799 	int *ncolored;
1800 	int *nfound;
1801 	int *ntrees;
1802 	got_pack_progress_cb progress_cb;
1803 	void *progress_arg;
1804 	struct got_ratelimit *rl;
1805 	got_cancel_cb cancel_cb;
1806 	void *cancel_arg;
1807 };
1808 
1809 static const struct got_error *
1810 load_packed_commit_id(void *arg, time_t mtime, struct got_object_id *id,
1811     struct got_repository *repo)
1812 {
1813 	struct load_packed_obj_arg *a = arg;
1814 
1815 	if (got_object_idset_contains(a->idset, id) ||
1816 	    got_object_idset_contains(a->idset_exclude, id))
1817 		return NULL;
1818 
1819 	return add_object(a->want_meta,
1820 	    a->want_meta ? a->idset : a->idset_exclude,
1821 	    id, "", GOT_OBJ_TYPE_COMMIT, mtime, a->seed, a->loose_obj_only,
1822 	    repo, a->ncolored, a->nfound, a->ntrees,
1823 	    a->progress_cb, a->progress_arg, a->rl);
1824 }
1825 
1826 static const struct got_error *
1827 load_packed_tree_ids(void *arg, struct got_tree_object *tree, time_t mtime,
1828     struct got_object_id *id, const char *dpath, struct got_repository *repo)
1829 {
1830 	const struct got_error *err;
1831 	struct load_packed_obj_arg *a = arg;
1832 	const char *relpath;
1833 
1834 	/*
1835 	 * When we receive a tree's ID and path but not the tree itself,
1836 	 * this tree object was not found in the pack file. This is the
1837 	 * last time we are being called for this optimized traversal.
1838 	 * Return from here and switch to loading objects the slow way.
1839 	 */
1840 	if (tree == NULL) {
1841 		free(a->id);
1842 		a->id = got_object_id_dup(id);
1843 		if (a->id == NULL) {
1844 			err = got_error_from_errno("got_object_id_dup");
1845 			free(a->dpath);
1846 			a->dpath = NULL;
1847 			return err;
1848 		}
1849 
1850 		free(a->dpath);
1851 		a->dpath = strdup(dpath);
1852 		if (a->dpath == NULL) {
1853 			err = got_error_from_errno("strdup");
1854 			free(a->id);
1855 			a->id = NULL;
1856 			return err;
1857 		}
1858 
1859 		a->mtime = mtime;
1860 		return NULL;
1861 	}
1862 
1863 	if (got_object_idset_contains(a->idset, id) ||
1864 	    got_object_idset_contains(a->idset_exclude, id))
1865 		return NULL;
1866 
1867 	relpath = dpath;
1868 	while (relpath[0] == '/')
1869 		relpath++;
1870 
1871 	err = add_object(a->want_meta,
1872 	    a->want_meta ? a->idset : a->idset_exclude,
1873 	    id, relpath, GOT_OBJ_TYPE_TREE, mtime, a->seed,
1874 	    a->loose_obj_only, repo, a->ncolored, a->nfound, a->ntrees,
1875 	    a->progress_cb, a->progress_arg, a->rl);
1876 	if (err)
1877 		return err;
1878 
1879 	return load_tree_entries(NULL, a->want_meta, a->idset,
1880 	    a->idset_exclude, tree, dpath, mtime, a->seed, repo,
1881 	    a->loose_obj_only, a->ncolored, a->nfound, a->ntrees,
1882 	    a->progress_cb, a->progress_arg, a->rl,
1883 	    a->cancel_cb, a->cancel_arg);
1884 }
1885 
1886 static const struct got_error *
1887 load_packed_object_ids(int *found_all_objects,
1888     struct got_object_id **ours, int nours,
1889     struct got_object_id **theirs, int ntheirs,
1890     int want_meta, uint32_t seed, struct got_object_idset *idset,
1891     struct got_object_idset *idset_exclude, int loose_obj_only,
1892     struct got_repository *repo, struct got_packidx *packidx,
1893     int *ncolored, int *nfound, int *ntrees,
1894     got_pack_progress_cb progress_cb, void *progress_arg,
1895     struct got_ratelimit *rl, got_cancel_cb cancel_cb, void *cancel_arg)
1896 {
1897 	const struct got_error *err = NULL;
1898 	struct load_packed_obj_arg lpa;
1899 
1900 	memset(&lpa, 0, sizeof(lpa));
1901 	lpa.seed = seed;
1902 	lpa.want_meta = want_meta;
1903 	lpa.idset = idset;
1904 	lpa.idset_exclude = idset_exclude;
1905 	lpa.loose_obj_only = loose_obj_only;
1906 	lpa.ncolored = ncolored;
1907 	lpa.nfound = nfound;
1908 	lpa.ntrees = ntrees;
1909 	lpa.progress_cb = progress_cb;
1910 	lpa.progress_arg = progress_arg;
1911 	lpa.rl = rl;
1912 	lpa.cancel_cb = cancel_cb;
1913 	lpa.cancel_arg = cancel_arg;
1914 
1915 	/* Attempt to load objects via got-read-pack, as far as possible. */
1916 	err = got_object_enumerate(found_all_objects, load_packed_commit_id,
1917 	   load_packed_tree_ids, &lpa, ours, nours, theirs, ntheirs,
1918 	   packidx, repo);
1919 	if (err)
1920 		return err;
1921 
1922 	if (lpa.id == NULL)
1923 		return NULL;
1924 
1925 	/*
1926 	 * An incomplete tree hierarchy was present in the pack file
1927 	 * and caused loading to be aborted.
1928 	 * Continue loading trees the slow way.
1929 	 */
1930 	err = load_tree(want_meta, idset, idset_exclude,
1931 	    lpa.id, lpa.dpath, lpa.mtime, seed, repo, loose_obj_only,
1932 	    ncolored, nfound, ntrees, progress_cb, progress_arg, rl,
1933 	    cancel_cb, cancel_arg);
1934 	free(lpa.id);
1935 	free(lpa.dpath);
1936 	return err;
1937 }
1938 
1939 static const struct got_error *
1940 find_pack_for_enumeration(struct got_packidx **best_packidx,
1941     struct got_object_id **ids, int nids, struct got_repository *repo)
1942 {
1943 	const struct got_error *err = NULL;
1944 	struct got_pathlist_entry *pe;
1945 	const char *best_packidx_path = NULL;
1946 	int nobj_max = 0;
1947 	int ncommits_max = 0;
1948 
1949 	*best_packidx = NULL;
1950 
1951 	/*
1952 	 * Find the largest pack which contains at least some of the
1953 	 * commits and tags we are interested in.
1954 	 */
1955 	TAILQ_FOREACH(pe, &repo->packidx_paths, entry) {
1956 		const char *path_packidx = pe->path;
1957 		struct got_packidx *packidx;
1958 		int nobj, i, idx, ncommits = 0;
1959 
1960 		err = got_repo_get_packidx(&packidx, path_packidx, repo);
1961 		if (err)
1962 			break;
1963 
1964 		nobj = be32toh(packidx->hdr.fanout_table[0xff]);
1965 		if (nobj <= nobj_max)
1966 			continue;
1967 
1968 		for (i = 0; i < nids; i++) {
1969 			idx = got_packidx_get_object_idx(packidx, ids[i]);
1970 			if (idx != -1)
1971 				ncommits++;
1972 		}
1973 		if (ncommits > ncommits_max) {
1974 			best_packidx_path = path_packidx;
1975 			nobj_max = nobj;
1976 			ncommits_max = ncommits;
1977 		}
1978 	}
1979 
1980 	if (best_packidx_path && err == NULL) {
1981 		err = got_repo_get_packidx(best_packidx, best_packidx_path,
1982 		    repo);
1983 	}
1984 
1985 	return err;
1986 }
1987 
1988 static const struct got_error *
1989 load_object_ids(int *ncolored, int *nfound, int *ntrees,
1990     struct got_object_idset *idset, struct got_object_id **theirs, int ntheirs,
1991     struct got_object_id **ours, int nours, struct got_repository *repo,
1992     uint32_t seed, int loose_obj_only, got_pack_progress_cb progress_cb,
1993     void *progress_arg, struct got_ratelimit *rl, got_cancel_cb cancel_cb,
1994     void *cancel_arg)
1995 {
1996 	const struct got_error *err = NULL;
1997 	struct got_object_id **ids = NULL;
1998 	struct got_packidx *packidx = NULL;
1999 	int i, nobj = 0, obj_type, found_all_objects = 0;
2000 	struct got_object_idset *idset_exclude;
2001 
2002 	idset_exclude = got_object_idset_alloc();
2003 	if (idset_exclude == NULL)
2004 		return got_error_from_errno("got_object_idset_alloc");
2005 
2006 	*ncolored = 0;
2007 	*nfound = 0;
2008 	*ntrees = 0;
2009 
2010 	err = findtwixt(&ids, &nobj, ncolored, ours, nours, theirs, ntheirs,
2011 	    repo, progress_cb, progress_arg, rl, cancel_cb, cancel_arg);
2012 	if (err)
2013 		goto done;
2014 
2015 	err = find_pack_for_enumeration(&packidx, theirs, ntheirs, repo);
2016 	if (err)
2017 		goto done;
2018 	if (packidx) {
2019 		err = load_packed_object_ids(&found_all_objects,
2020 		    theirs, ntheirs, NULL, 0, 0, seed, idset, idset_exclude,
2021 		    loose_obj_only, repo, packidx, ncolored, nfound, ntrees,
2022 		    progress_cb, progress_arg, rl, cancel_cb, cancel_arg);
2023 		if (err)
2024 			goto done;
2025 	}
2026 
2027 	for (i = 0; i < ntheirs; i++) {
2028 		struct got_object_id *id = theirs[i];
2029 		if (id == NULL)
2030 			continue;
2031 		err = got_object_get_type(&obj_type, repo, id);
2032 		if (err)
2033 			return err;
2034 		if (obj_type == GOT_OBJ_TYPE_COMMIT) {
2035 			if (!found_all_objects) {
2036 				err = load_commit(0, idset, idset_exclude,
2037 				    id, repo, seed, loose_obj_only,
2038 				    ncolored, nfound, ntrees,
2039 				    progress_cb, progress_arg, rl,
2040 				    cancel_cb, cancel_arg);
2041 				if (err)
2042 					goto done;
2043 			}
2044 		} else if (obj_type == GOT_OBJ_TYPE_TAG) {
2045 			err = load_tag(0, idset, idset_exclude, id, repo,
2046 			    seed, loose_obj_only, ncolored, nfound, ntrees,
2047 			    progress_cb, progress_arg, rl,
2048 			    cancel_cb, cancel_arg);
2049 			if (err)
2050 				goto done;
2051 		}
2052 	}
2053 
2054 	found_all_objects = 0;
2055 	err = find_pack_for_enumeration(&packidx, ids, nobj, repo);
2056 	if (err)
2057 		goto done;
2058 	if (packidx) {
2059 		err = load_packed_object_ids(&found_all_objects, ids,
2060 		    nobj, theirs, ntheirs, 1, seed, idset, idset_exclude,
2061 		    loose_obj_only, repo, packidx, ncolored, nfound, ntrees,
2062 		    progress_cb, progress_arg, rl, cancel_cb, cancel_arg);
2063 		if (err)
2064 			goto done;
2065 	}
2066 
2067 	if (!found_all_objects) {
2068 		for (i = 0; i < nobj; i++) {
2069 			err = load_commit(1, idset, idset_exclude, ids[i],
2070 			    repo, seed, loose_obj_only, ncolored, nfound,
2071 			    ntrees, progress_cb, progress_arg, rl,
2072 			    cancel_cb, cancel_arg);
2073 			if (err)
2074 				goto done;
2075 		}
2076 	}
2077 
2078 	for (i = 0; i < nours; i++) {
2079 		struct got_object_id *id = ours[i];
2080 		struct got_pack_meta *m;
2081 		if (id == NULL)
2082 			continue;
2083 		m = got_object_idset_get(idset, id);
2084 		if (m == NULL) {
2085 			err = got_object_get_type(&obj_type, repo, id);
2086 			if (err)
2087 				goto done;
2088 		} else
2089 			obj_type = m->obj_type;
2090 		if (obj_type != GOT_OBJ_TYPE_TAG)
2091 			continue;
2092 		err = load_tag(1, idset, idset_exclude, id, repo,
2093 		    seed, loose_obj_only, ncolored, nfound, ntrees,
2094 		    progress_cb, progress_arg, rl, cancel_cb, cancel_arg);
2095 		if (err)
2096 			goto done;
2097 	}
2098 done:
2099 	for (i = 0; i < nobj; i++) {
2100 		free(ids[i]);
2101 	}
2102 	free(ids);
2103 	got_object_idset_free(idset_exclude);
2104 	return err;
2105 }
2106 
2107 static const struct got_error *
2108 hwrite(int fd, const void *buf, off_t len, SHA1_CTX *ctx)
2109 {
2110 	ssize_t w;
2111 
2112 	SHA1Update(ctx, buf, len);
2113 	w = write(fd, buf, len);
2114 	if (w == -1)
2115 		return got_error_from_errno("write");
2116 	else if (w != len)
2117 		return got_error(GOT_ERR_IO);
2118 	return NULL;
2119 }
2120 
2121 static const struct got_error *
2122 hcopy(FILE *fsrc, int fd_dst, off_t len, SHA1_CTX *ctx)
2123 {
2124 	unsigned char buf[65536];
2125 	off_t remain = len;
2126 	size_t n;
2127 	ssize_t w;
2128 
2129 	while (remain > 0) {
2130 		size_t copylen = MIN(sizeof(buf), remain);
2131 		n = fread(buf, 1, copylen, fsrc);
2132 		if (n != copylen)
2133 			return got_ferror(fsrc, GOT_ERR_IO);
2134 		SHA1Update(ctx, buf, copylen);
2135 		w = write(fd_dst, buf, copylen);
2136 		if (w == -1)
2137 			return got_error_from_errno("write");
2138 		else if (w != copylen)
2139 			return got_error(GOT_ERR_IO);
2140 		remain -= copylen;
2141 	}
2142 
2143 	return NULL;
2144 }
2145 
2146 static const struct got_error *
2147 hcopy_mmap(uint8_t *src, off_t src_offset, size_t src_size,
2148     int fd, off_t len, SHA1_CTX *ctx)
2149 {
2150 	ssize_t w;
2151 
2152 	if (src_offset + len > src_size)
2153 		return got_error(GOT_ERR_RANGE);
2154 
2155 	SHA1Update(ctx, src + src_offset, len);
2156 	w = write(fd, src + src_offset, len);
2157 	if (w == -1)
2158 		return got_error_from_errno("write");
2159 	else if (w != len)
2160 		return got_error(GOT_ERR_IO);
2161 	return NULL;
2162 }
2163 
2164 static void
2165 putbe32(char *b, uint32_t n)
2166 {
2167 	b[0] = n >> 24;
2168 	b[1] = n >> 16;
2169 	b[2] = n >> 8;
2170 	b[3] = n >> 0;
2171 }
2172 
2173 static int
2174 write_order_cmp(const void *pa, const void *pb)
2175 {
2176 	struct got_pack_meta *a, *b, *ahd, *bhd;
2177 
2178 	a = *(struct got_pack_meta **)pa;
2179 	b = *(struct got_pack_meta **)pb;
2180 	ahd = (a->head == NULL) ? a : a->head;
2181 	bhd = (b->head == NULL) ? b : b->head;
2182 	if (bhd->mtime < ahd->mtime)
2183 		return -1;
2184 	if (bhd->mtime > ahd->mtime)
2185 		return 1;
2186 	if (bhd < ahd)
2187 		return -1;
2188 	if (bhd > ahd)
2189 		return 1;
2190 	if (a->nchain != b->nchain)
2191 		return a->nchain - b->nchain;
2192 	if (a->mtime < b->mtime)
2193 		return -1;
2194 	if (a->mtime > b->mtime)
2195 		return 1;
2196 	return got_object_id_cmp(&a->id, &b->id);
2197 }
2198 
2199 static int
2200 reuse_write_order_cmp(const void *pa, const void *pb)
2201 {
2202 	struct got_pack_meta *a, *b;
2203 
2204 	a = *(struct got_pack_meta **)pa;
2205 	b = *(struct got_pack_meta **)pb;
2206 
2207 	if (a->reused_delta_offset < b->reused_delta_offset)
2208 		return -1;
2209 	if (a->reused_delta_offset > b->reused_delta_offset)
2210 		return 1;
2211 	return 0;
2212 }
2213 
2214 static const struct got_error *
2215 packhdr(int *hdrlen, char *hdr, size_t bufsize, int obj_type, size_t len)
2216 {
2217 	size_t i;
2218 
2219 	*hdrlen = 0;
2220 
2221 	hdr[0] = obj_type << 4;
2222 	hdr[0] |= len & 0xf;
2223 	len >>= 4;
2224 	for (i = 1; len != 0; i++){
2225 		if (i >= bufsize)
2226 			return got_error(GOT_ERR_NO_SPACE);
2227 		hdr[i - 1] |= GOT_DELTA_SIZE_MORE;
2228 		hdr[i] = len & GOT_DELTA_SIZE_VAL_MASK;
2229 		len >>= GOT_DELTA_SIZE_SHIFT;
2230 	}
2231 
2232 	*hdrlen = i;
2233 	return NULL;
2234 }
2235 
2236 static int
2237 packoff(char *hdr, off_t off)
2238 {
2239 	int i, j;
2240 	char rbuf[8];
2241 
2242 	rbuf[0] = off & GOT_DELTA_SIZE_VAL_MASK;
2243 	for (i = 1; (off >>= GOT_DELTA_SIZE_SHIFT) != 0; i++) {
2244 		rbuf[i] = (--off & GOT_DELTA_SIZE_VAL_MASK) |
2245 		    GOT_DELTA_SIZE_MORE;
2246 	}
2247 
2248 	j = 0;
2249 	while (i > 0)
2250 		hdr[j++] = rbuf[--i];
2251 	return j;
2252 }
2253 
2254 static const struct got_error *
2255 deltahdr(off_t *packfile_size, SHA1_CTX *ctx, int packfd,
2256     struct got_pack_meta *m)
2257 {
2258 	const struct got_error *err;
2259 	char buf[32];
2260 	int nh;
2261 
2262 	if (m->prev->off != 0) {
2263 		err = packhdr(&nh, buf, sizeof(buf),
2264 		    GOT_OBJ_TYPE_OFFSET_DELTA, m->delta_len);
2265 		if (err)
2266 			return err;
2267 		nh += packoff(buf + nh, m->off - m->prev->off);
2268 		err = hwrite(packfd, buf, nh, ctx);
2269 		if (err)
2270 			return err;
2271 		*packfile_size += nh;
2272 	} else {
2273 		err = packhdr(&nh, buf, sizeof(buf),
2274 		    GOT_OBJ_TYPE_REF_DELTA, m->delta_len);
2275 		if (err)
2276 			return err;
2277 		err = hwrite(packfd, buf, nh, ctx);
2278 		if (err)
2279 			return err;
2280 		*packfile_size += nh;
2281 		err = hwrite(packfd, m->prev->id.sha1,
2282 		    sizeof(m->prev->id.sha1), ctx);
2283 		if (err)
2284 			return err;
2285 		*packfile_size += sizeof(m->prev->id.sha1);
2286 	}
2287 
2288 	return NULL;
2289 }
2290 
2291 static const struct got_error *
2292 write_packed_object(off_t *packfile_size, int packfd,
2293     FILE *delta_cache, uint8_t *delta_cache_map, size_t delta_cache_size,
2294     struct got_pack_meta *m, int *outfd, SHA1_CTX *ctx,
2295     struct got_repository *repo)
2296 {
2297 	const struct got_error *err = NULL;
2298 	struct got_deflate_checksum csum;
2299 	char buf[32];
2300 	int nh;
2301 	struct got_raw_object *raw = NULL;
2302 	off_t outlen;
2303 
2304 	csum.output_sha1 = ctx;
2305 	csum.output_crc = NULL;
2306 
2307 	m->off = *packfile_size;
2308 	if (m->delta_len == 0) {
2309 		err = got_object_raw_open(&raw, outfd, repo, &m->id);
2310 		if (err)
2311 			goto done;
2312 		err = packhdr(&nh, buf, sizeof(buf),
2313 		    m->obj_type, raw->size);
2314 		if (err)
2315 			goto done;
2316 		err = hwrite(packfd, buf, nh, ctx);
2317 		if (err)
2318 			goto done;
2319 		*packfile_size += nh;
2320 		if (raw->f == NULL) {
2321 			err = got_deflate_to_fd_mmap(&outlen,
2322 			    raw->data + raw->hdrlen, 0, raw->size,
2323 			    packfd, &csum);
2324 			if (err)
2325 				goto done;
2326 		} else {
2327 			if (fseeko(raw->f, raw->hdrlen, SEEK_SET)
2328 			    == -1) {
2329 				err = got_error_from_errno("fseeko");
2330 				goto done;
2331 			}
2332 			err = got_deflate_to_fd(&outlen, raw->f,
2333 			    raw->size, packfd, &csum);
2334 			if (err)
2335 				goto done;
2336 		}
2337 		*packfile_size += outlen;
2338 		got_object_raw_close(raw);
2339 		raw = NULL;
2340 	} else if (m->delta_buf) {
2341 		err = deltahdr(packfile_size, ctx, packfd, m);
2342 		if (err)
2343 			goto done;
2344 		err = hwrite(packfd, m->delta_buf,
2345 		    m->delta_compressed_len, ctx);
2346 		if (err)
2347 			goto done;
2348 		*packfile_size += m->delta_compressed_len;
2349 		free(m->delta_buf);
2350 		m->delta_buf = NULL;
2351 	} else if (delta_cache_map) {
2352 		err = deltahdr(packfile_size, ctx, packfd, m);
2353 		if (err)
2354 			goto done;
2355 		err = hcopy_mmap(delta_cache_map, m->delta_offset,
2356 		    delta_cache_size, packfd, m->delta_compressed_len,
2357 		    ctx);
2358 		if (err)
2359 			goto done;
2360 		*packfile_size += m->delta_compressed_len;
2361 	} else {
2362 		if (fseeko(delta_cache, m->delta_offset, SEEK_SET)
2363 		    == -1) {
2364 			err = got_error_from_errno("fseeko");
2365 			goto done;
2366 		}
2367 		err = deltahdr(packfile_size, ctx, packfd, m);
2368 		if (err)
2369 			goto done;
2370 		err = hcopy(delta_cache, packfd,
2371 		    m->delta_compressed_len, ctx);
2372 		if (err)
2373 			goto done;
2374 		*packfile_size += m->delta_compressed_len;
2375 	}
2376 done:
2377 	if (raw)
2378 		got_object_raw_close(raw);
2379 	return err;
2380 }
2381 
2382 static const struct got_error *
2383 genpack(uint8_t *pack_sha1, int packfd, FILE *delta_cache,
2384     struct got_pack_meta **deltify, int ndeltify,
2385     struct got_pack_meta **reuse, int nreuse,
2386     int ncolored, int nfound, int ntrees, int nours,
2387     struct got_repository *repo,
2388     got_pack_progress_cb progress_cb, void *progress_arg,
2389     struct got_ratelimit *rl,
2390     got_cancel_cb cancel_cb, void *cancel_arg)
2391 {
2392 	const struct got_error *err = NULL;
2393 	int i;
2394 	SHA1_CTX ctx;
2395 	struct got_pack_meta *m;
2396 	char buf[32];
2397 	ssize_t w;
2398 	off_t packfile_size = 0;
2399 	int outfd = -1;
2400 	int delta_cache_fd = -1;
2401 	uint8_t *delta_cache_map = NULL;
2402 	size_t delta_cache_size = 0;
2403 
2404 	SHA1Init(&ctx);
2405 
2406 #ifndef GOT_PACK_NO_MMAP
2407 	delta_cache_fd = dup(fileno(delta_cache));
2408 	if (delta_cache_fd != -1) {
2409 		struct stat sb;
2410 		if (fstat(delta_cache_fd, &sb) == -1) {
2411 			err = got_error_from_errno("fstat");
2412 			goto done;
2413 		}
2414 		if (sb.st_size > 0 && sb.st_size <= SIZE_MAX) {
2415 			delta_cache_map = mmap(NULL, sb.st_size,
2416 			    PROT_READ, MAP_PRIVATE, delta_cache_fd, 0);
2417 			if (delta_cache_map == MAP_FAILED) {
2418 				if (errno != ENOMEM) {
2419 					err = got_error_from_errno("mmap");
2420 					goto done;
2421 				}
2422 				delta_cache_map = NULL; /* fallback on stdio */
2423 			} else
2424 				delta_cache_size = (size_t)sb.st_size;
2425 		}
2426 	}
2427 #endif
2428 	err = hwrite(packfd, "PACK", 4, &ctx);
2429 	if (err)
2430 		goto done;
2431 	putbe32(buf, GOT_PACKFILE_VERSION);
2432 	err = hwrite(packfd, buf, 4, &ctx);
2433 	if (err)
2434 		goto done;
2435 	putbe32(buf, ndeltify + nreuse);
2436 	err = hwrite(packfd, buf, 4, &ctx);
2437 	if (err)
2438 		goto done;
2439 
2440 	qsort(deltify, ndeltify, sizeof(struct got_pack_meta *),
2441 	    write_order_cmp);
2442 	for (i = 0; i < ndeltify; i++) {
2443 		err = report_progress(progress_cb, progress_arg, rl,
2444 		    ncolored, nfound, ntrees, packfile_size, nours,
2445 		    ndeltify + nreuse, ndeltify + nreuse, i);
2446 		if (err)
2447 			goto done;
2448 		m = deltify[i];
2449 		err = write_packed_object(&packfile_size, packfd,
2450 		    delta_cache, delta_cache_map, delta_cache_size,
2451 		    m, &outfd, &ctx, repo);
2452 		if (err)
2453 			goto done;
2454 	}
2455 
2456 	qsort(reuse, nreuse, sizeof(struct got_pack_meta *),
2457 	    reuse_write_order_cmp);
2458 	for (i = 0; i < nreuse; i++) {
2459 		err = report_progress(progress_cb, progress_arg, rl,
2460 		    ncolored, nfound, ntrees, packfile_size, nours,
2461 		    ndeltify + nreuse, ndeltify + nreuse, ndeltify + i);
2462 		if (err)
2463 			goto done;
2464 		m = reuse[i];
2465 		err = write_packed_object(&packfile_size, packfd,
2466 		    delta_cache, delta_cache_map, delta_cache_size,
2467 		    m, &outfd, &ctx, repo);
2468 		if (err)
2469 			goto done;
2470 	}
2471 
2472 	SHA1Final(pack_sha1, &ctx);
2473 	w = write(packfd, pack_sha1, SHA1_DIGEST_LENGTH);
2474 	if (w == -1)
2475 		err = got_error_from_errno("write");
2476 	else if (w != SHA1_DIGEST_LENGTH)
2477 		err = got_error(GOT_ERR_IO);
2478 	if (err)
2479 		goto done;
2480 	packfile_size += SHA1_DIGEST_LENGTH;
2481 	packfile_size += sizeof(struct got_packfile_hdr);
2482 	if (progress_cb) {
2483 		err = progress_cb(progress_arg, ncolored, nfound, ntrees,
2484 		    packfile_size, nours, ndeltify + nreuse,
2485 		    ndeltify + nreuse, ndeltify + nreuse);
2486 		if (err)
2487 			goto done;
2488 	}
2489 done:
2490 	if (outfd != -1 && close(outfd) == -1 && err == NULL)
2491 		err = got_error_from_errno("close");
2492 	if (delta_cache_map && munmap(delta_cache_map, delta_cache_size) == -1)
2493 		err = got_error_from_errno("munmap");
2494 	if (delta_cache_fd != -1 && close(delta_cache_fd) == -1 && err == NULL)
2495 		err = got_error_from_errno("close");
2496 	return err;
2497 }
2498 
2499 static const struct got_error *
2500 add_meta_idset_cb(struct got_object_id *id, void *data, void *arg)
2501 {
2502 	struct got_pack_meta *m = data;
2503 	struct got_pack_metavec *v = arg;
2504 
2505 	if (m->reused_delta_offset != 0)
2506 		return NULL;
2507 
2508 	return add_meta(m, v);
2509 }
2510 
2511 const struct got_error *
2512 got_pack_create(uint8_t *packsha1, int packfd, FILE *delta_cache,
2513     struct got_object_id **theirs, int ntheirs,
2514     struct got_object_id **ours, int nours,
2515     struct got_repository *repo, int loose_obj_only, int allow_empty,
2516     got_pack_progress_cb progress_cb, void *progress_arg,
2517     got_cancel_cb cancel_cb, void *cancel_arg)
2518 {
2519 	const struct got_error *err;
2520 	int delta_cache_fd = -1;
2521 	struct got_object_idset *idset;
2522 	struct got_ratelimit rl;
2523 	struct got_pack_metavec deltify, reuse;
2524 	int ncolored = 0, nfound = 0, ntrees = 0;
2525 	size_t ndeltify;
2526 	uint32_t seed;
2527 
2528 	seed = arc4random();
2529 
2530 	memset(&deltify, 0, sizeof(deltify));
2531 	memset(&reuse, 0, sizeof(reuse));
2532 
2533 	got_ratelimit_init(&rl, 0, 500);
2534 
2535 	idset = got_object_idset_alloc();
2536 	if (idset == NULL)
2537 		return got_error_from_errno("got_object_idset_alloc");
2538 
2539 	err = load_object_ids(&ncolored, &nfound, &ntrees, idset, theirs,
2540 	    ntheirs, ours, nours, repo, seed, loose_obj_only,
2541 	    progress_cb, progress_arg, &rl, cancel_cb, cancel_arg);
2542 	if (err)
2543 		goto done;
2544 
2545 	if (progress_cb) {
2546 		err = progress_cb(progress_arg, ncolored, nfound, ntrees,
2547 		    0L, nours, got_object_idset_num_elements(idset), 0, 0);
2548 		if (err)
2549 			goto done;
2550 	}
2551 
2552 	if (got_object_idset_num_elements(idset) == 0 && !allow_empty) {
2553 		err = got_error(GOT_ERR_CANNOT_PACK);
2554 		goto done;
2555 	}
2556 
2557 	delta_cache_fd = dup(fileno(delta_cache));
2558 	if (delta_cache_fd == -1) {
2559 		err = got_error_from_errno("dup");
2560 		goto done;
2561 	}
2562 
2563 	reuse.metasz = 64;
2564 	reuse.meta = calloc(reuse.metasz,
2565 	    sizeof(struct got_pack_meta *));
2566 	if (reuse.meta == NULL) {
2567 		err = got_error_from_errno("calloc");
2568 		goto done;
2569 	}
2570 
2571 	err = search_deltas(&reuse, idset, delta_cache_fd, ncolored, nfound,
2572 	    ntrees, nours, repo, progress_cb, progress_arg, &rl,
2573 	    cancel_cb, cancel_arg);
2574 	if (err)
2575 		goto done;
2576 
2577 	if (fseeko(delta_cache, 0L, SEEK_END) == -1) {
2578 		err = got_error_from_errno("fseeko");
2579 		goto done;
2580 	}
2581 
2582 	ndeltify = got_object_idset_num_elements(idset) - reuse.nmeta;
2583 	if (ndeltify > 0) {
2584 		deltify.meta = calloc(ndeltify, sizeof(struct got_pack_meta *));
2585 		if (deltify.meta == NULL) {
2586 			err = got_error_from_errno("calloc");
2587 			goto done;
2588 		}
2589 		deltify.metasz = ndeltify;
2590 
2591 		err = got_object_idset_for_each(idset, add_meta_idset_cb,
2592 		    &deltify);
2593 		if (err)
2594 			goto done;
2595 		if (deltify.nmeta > 0) {
2596 			err = pick_deltas(deltify.meta, deltify.nmeta,
2597 			    ncolored, nfound, ntrees, nours, reuse.nmeta,
2598 			    delta_cache, repo, progress_cb, progress_arg, &rl,
2599 			    cancel_cb, cancel_arg);
2600 			if (err)
2601 				goto done;
2602 		}
2603 	}
2604 
2605 	if (fflush(delta_cache) == EOF) {
2606 		err = got_error_from_errno("fflush");
2607 		goto done;
2608 	}
2609 	err = genpack(packsha1, packfd, delta_cache, deltify.meta,
2610 	    deltify.nmeta, reuse.meta, reuse.nmeta, ncolored, nfound, ntrees,
2611 	    nours, repo, progress_cb, progress_arg, &rl,
2612 	    cancel_cb, cancel_arg);
2613 	if (err)
2614 		goto done;
2615 done:
2616 	free_nmeta(deltify.meta, deltify.nmeta);
2617 	free_nmeta(reuse.meta, reuse.nmeta);
2618 	got_object_idset_free(idset);
2619 	if (delta_cache_fd != -1 && close(delta_cache_fd) == -1 && err == NULL)
2620 		err = got_error_from_errno("close");
2621 	return err;
2622 }