1 /*
2  * Copyright (c) 2019 Ori Bernstein <ori@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/types.h>
18 #include <sys/queue.h>
19 #include <sys/uio.h>
20 #include <sys/time.h>
21 #include <sys/stat.h>
22 
23 #include <stdint.h>
24 #include <errno.h>
25 #include <imsg.h>
26 #include <limits.h>
27 #include <signal.h>
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <ctype.h>
32 #include <sha1.h>
33 #include <fcntl.h>
34 #include <unistd.h>
35 #include <zlib.h>
36 #include <err.h>
37 
38 #include "got_error.h"
39 #include "got_object.h"
40 #include "got_path.h"
41 #include "got_version.h"
42 #include "got_fetch.h"
43 #include "got_reference.h"
44 
45 #include "got_lib_sha1.h"
46 #include "got_lib_delta.h"
47 #include "got_lib_object.h"
48 #include "got_lib_object_parse.h"
49 #include "got_lib_privsep.h"
50 #include "got_lib_pack.h"
51 #include "got_lib_pkt.h"
52 #include "got_lib_gitproto.h"
53 
54 #ifndef nitems
55 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
56 #endif
57 
58 struct got_object *indexed;
59 static int chattygot;
60 
61 static const struct got_capability got_capabilities[] = {
62 	{ GOT_CAPA_AGENT, "got/" GOT_VERSION_STR },
63 	{ GOT_CAPA_OFS_DELTA, NULL },
64 	{ GOT_CAPA_SIDE_BAND_64K, NULL },
65 };
66 
67 static void
68 match_remote_ref(struct got_pathlist_head *have_refs,
69     struct got_object_id *my_id, char *refname)
70 {
71 	struct got_pathlist_entry *pe;
72 
73 	/* XXX zero-hash signifies we don't have this ref;
74 	 * we should use a flag instead */
75 	memset(my_id, 0, sizeof(*my_id));
76 
77 	TAILQ_FOREACH(pe, have_refs, entry) {
78 		struct got_object_id *id = pe->data;
79 		if (strcmp(pe->path, refname) == 0) { 
80 			memcpy(my_id, id, sizeof(*my_id));
81 			break;
82 		}
83 	}
84 }
85 
86 static int
87 match_branch(const char *branch, const char *wanted_branch)
88 {
89 	if (strncmp(branch, "refs/heads/", 11) != 0)
90 		return 0;
91 
92 	if (strncmp(wanted_branch, "refs/heads/", 11) == 0)
93 		wanted_branch += 11;
94 
95 	return (strcmp(branch + 11, wanted_branch) == 0);
96 }
97 
98 static int
99 match_wanted_ref(const char *refname, const char *wanted_ref)
100 {
101 	if (strncmp(refname, "refs/", 5) != 0)
102 		return 0;
103 	refname += 5;
104 
105 	/*
106 	 * Prevent fetching of references that won't make any
107 	 * sense outside of the remote repository's context.
108 	 */
109 	if (strncmp(refname, "got/", 4) == 0)
110 		return 0;
111 	if (strncmp(refname, "remotes/", 8) == 0)
112 		return 0;
113 
114 	if (strncmp(wanted_ref, "refs/", 5) == 0)
115 		wanted_ref += 5;
116 
117 	/* Allow prefix match. */
118 	if (got_path_is_child(refname, wanted_ref, strlen(wanted_ref)))
119 		return 1;
120 
121 	/* Allow exact match. */
122 	return (strcmp(refname, wanted_ref) == 0);
123 }
124 
125 static const struct got_error *
126 send_fetch_server_progress(struct imsgbuf *ibuf, const char *msg, size_t msglen)
127 {
128 	if (msglen > MAX_IMSGSIZE - IMSG_HEADER_SIZE)
129 		return got_error(GOT_ERR_NO_SPACE);
130 
131 	if (msglen == 0)
132 		return NULL;
133 
134 	if (imsg_compose(ibuf, GOT_IMSG_FETCH_SERVER_PROGRESS, 0, 0, -1,
135 	    msg, msglen) == -1)
136 		return got_error_from_errno(
137 		    "imsg_compose FETCH_SERVER_PROGRESS");
138 
139 	return got_privsep_flush_imsg(ibuf);
140 }
141 
142 static const struct got_error *
143 send_fetch_download_progress(struct imsgbuf *ibuf, off_t bytes)
144 {
145 	if (imsg_compose(ibuf, GOT_IMSG_FETCH_DOWNLOAD_PROGRESS, 0, 0, -1,
146 	    &bytes, sizeof(bytes)) == -1)
147 		return got_error_from_errno(
148 		    "imsg_compose FETCH_DOWNLOAD_PROGRESS");
149 
150 	return got_privsep_flush_imsg(ibuf);
151 }
152 
153 static const struct got_error *
154 send_fetch_done(struct imsgbuf *ibuf, uint8_t *pack_sha1)
155 {
156 	if (imsg_compose(ibuf, GOT_IMSG_FETCH_DONE, 0, 0, -1,
157 	    pack_sha1, SHA1_DIGEST_LENGTH) == -1)
158 		return got_error_from_errno("imsg_compose FETCH");
159 	return got_privsep_flush_imsg(ibuf);
160 }
161 
162 static const struct got_error *
163 fetch_progress(struct imsgbuf *ibuf, const char *buf, size_t len)
164 {
165 	size_t i;
166 
167 	if (len == 0)
168 		return NULL;
169 
170 	/*
171 	 * Truncate messages which exceed the maximum imsg payload size.
172 	 * Server may send up to 64k.
173 	 */
174 	if (len > MAX_IMSGSIZE - IMSG_HEADER_SIZE)
175 		len = MAX_IMSGSIZE - IMSG_HEADER_SIZE;
176 
177 	/* Only allow printable ASCII. */
178 	for (i = 0; i < len; i++) {
179 		if (isprint((unsigned char)buf[i]) ||
180 		    isspace((unsigned char)buf[i]))
181 			continue;
182 		return got_error_msg(GOT_ERR_BAD_PACKET,
183 		    "non-printable progress message received from server");
184 	}
185 
186 	return send_fetch_server_progress(ibuf, buf, len);
187 }
188 
189 static const struct got_error *
190 fetch_error(const char *buf, size_t len)
191 {
192 	static char msg[1024];
193 	size_t i;
194 
195 	for (i = 0; i < len && i < sizeof(msg) - 1; i++) {
196 		if (!isprint(buf[i]))
197 			return got_error_msg(GOT_ERR_BAD_PACKET,
198 			    "non-printable error message received from server");
199 		msg[i] = buf[i];
200 	}
201 	msg[i] = '\0';
202 	return got_error_msg(GOT_ERR_FETCH_FAILED, msg);
203 }
204 
205 static const struct got_error *
206 send_fetch_symrefs(struct imsgbuf *ibuf, struct got_pathlist_head *symrefs)
207 {
208 	const struct got_error *err = NULL;
209 	struct ibuf *wbuf;
210 	size_t len, nsymrefs = 0;
211 	struct got_pathlist_entry *pe;
212 
213 	len = sizeof(struct got_imsg_fetch_symrefs);
214 	TAILQ_FOREACH(pe, symrefs, entry) {
215 		const char *target = pe->data;
216 		len += sizeof(struct got_imsg_fetch_symref) +
217 		    pe->path_len + strlen(target);
218 		nsymrefs++;
219 	}
220 
221 	if (len >= MAX_IMSGSIZE - IMSG_HEADER_SIZE)
222 		return got_error(GOT_ERR_NO_SPACE);
223 
224 	wbuf = imsg_create(ibuf, GOT_IMSG_FETCH_SYMREFS, 0, 0, len);
225 	if (wbuf == NULL)
226 		return got_error_from_errno("imsg_create FETCH_SYMREFS");
227 
228 	/* Keep in sync with struct got_imsg_fetch_symrefs definition! */
229 	if (imsg_add(wbuf, &nsymrefs, sizeof(nsymrefs)) == -1) {
230 		err = got_error_from_errno("imsg_add FETCH_SYMREFS");
231 		ibuf_free(wbuf);
232 		return err;
233 	}
234 
235 	TAILQ_FOREACH(pe, symrefs, entry) {
236 		const char *name = pe->path;
237 		size_t name_len = pe->path_len;
238 		const char *target = pe->data;
239 		size_t target_len = strlen(target);
240 
241 		/* Keep in sync with struct got_imsg_fetch_symref definition! */
242 		if (imsg_add(wbuf, &name_len, sizeof(name_len)) == -1) {
243 			err = got_error_from_errno("imsg_add FETCH_SYMREFS");
244 			ibuf_free(wbuf);
245 			return err;
246 		}
247 		if (imsg_add(wbuf, &target_len, sizeof(target_len)) == -1) {
248 			err = got_error_from_errno("imsg_add FETCH_SYMREFS");
249 			ibuf_free(wbuf);
250 			return err;
251 		}
252 		if (imsg_add(wbuf, name, name_len) == -1) {
253 			err = got_error_from_errno("imsg_add FETCH_SYMREFS");
254 			ibuf_free(wbuf);
255 			return err;
256 		}
257 		if (imsg_add(wbuf, target, target_len) == -1) {
258 			err = got_error_from_errno("imsg_add FETCH_SYMREFS");
259 			ibuf_free(wbuf);
260 			return err;
261 		}
262 	}
263 
264 	wbuf->fd = -1;
265 	imsg_close(ibuf, wbuf);
266 	return got_privsep_flush_imsg(ibuf);
267 }
268 
269 static const struct got_error *
270 send_fetch_ref(struct imsgbuf *ibuf, struct got_object_id *refid,
271     const char *refname)
272 {
273 	const struct got_error *err = NULL;
274 	struct ibuf *wbuf;
275 	size_t len, reflen = strlen(refname);
276 
277 	len = sizeof(struct got_imsg_fetch_ref) + reflen;
278 	if (len >= MAX_IMSGSIZE - IMSG_HEADER_SIZE)
279 		return got_error(GOT_ERR_NO_SPACE);
280 
281 	wbuf = imsg_create(ibuf, GOT_IMSG_FETCH_REF, 0, 0, len);
282 	if (wbuf == NULL)
283 		return got_error_from_errno("imsg_create FETCH_REF");
284 
285 	/* Keep in sync with struct got_imsg_fetch_ref definition! */
286 	if (imsg_add(wbuf, refid->sha1, SHA1_DIGEST_LENGTH) == -1) {
287 		err = got_error_from_errno("imsg_add FETCH_REF");
288 		ibuf_free(wbuf);
289 		return err;
290 	}
291 	if (imsg_add(wbuf, refname, reflen) == -1) {
292 		err = got_error_from_errno("imsg_add FETCH_REF");
293 		ibuf_free(wbuf);
294 		return err;
295 	}
296 
297 	wbuf->fd = -1;
298 	imsg_close(ibuf, wbuf);
299 	return got_privsep_flush_imsg(ibuf);
300 }
301 
302 static const struct got_error *
303 fetch_pack(int fd, int packfd, uint8_t *pack_sha1,
304     struct got_pathlist_head *have_refs, int fetch_all_branches,
305     struct got_pathlist_head *wanted_branches,
306     struct got_pathlist_head *wanted_refs, int list_refs_only,
307     struct imsgbuf *ibuf)
308 {
309 	const struct got_error *err = NULL;
310 	char buf[GOT_PKT_MAX];
311 	char hashstr[SHA1_DIGEST_STRING_LENGTH];
312 	struct got_object_id *have, *want;
313 	int is_firstpkt = 1, nref = 0, refsz = 16;
314 	int i, n, nwant = 0, nhave = 0, acked = 0;
315 	off_t packsz = 0, last_reported_packsz = 0;
316 	char *id_str = NULL, *refname = NULL;
317 	char *server_capabilities = NULL, *my_capabilities = NULL;
318 	const char *default_branch = NULL;
319 	struct got_pathlist_head symrefs;
320 	struct got_pathlist_entry *pe;
321 	int sent_my_capabilites = 0, have_sidebands = 0;
322 	int found_branch = 0;
323 	SHA1_CTX sha1_ctx;
324 	uint8_t sha1_buf[SHA1_DIGEST_LENGTH];
325 	size_t sha1_buf_len = 0;
326 	ssize_t w;
327 
328 	TAILQ_INIT(&symrefs);
329 	SHA1Init(&sha1_ctx);
330 
331 	have = malloc(refsz * sizeof(have[0]));
332 	if (have == NULL)
333 		return got_error_from_errno("malloc");
334 	want = malloc(refsz * sizeof(want[0]));
335 	if (want == NULL) {
336 		err = got_error_from_errno("malloc");
337 		goto done;
338 	}
339 	while (1) {
340 		err = got_pkt_readpkt(&n, fd, buf, sizeof(buf), chattygot);
341 		if (err)
342 			goto done;
343 		if (n == 0)
344 			break;
345 		if (n >= 4 && strncmp(buf, "ERR ", 4) == 0) {
346 			err = fetch_error(&buf[4], n - 4);
347 			goto done;
348 		}
349 		free(id_str);
350 		free(refname);
351 		err = got_gitproto_parse_refline(&id_str, &refname,
352 		    &server_capabilities, buf, n);
353 		if (err)
354 			goto done;
355 		if (is_firstpkt) {
356 			if (chattygot && server_capabilities[0] != '\0')
357 				fprintf(stderr, "%s: server capabilities: %s\n",
358 				    getprogname(), server_capabilities);
359 			err = got_gitproto_match_capabilities(&my_capabilities,
360 			    &symrefs, server_capabilities,
361 			    got_capabilities, nitems(got_capabilities));
362 			if (err)
363 				goto done;
364 			if (chattygot)
365 				fprintf(stderr, "%s: my capabilities:%s\n",
366 				    getprogname(), my_capabilities != NULL ?
367 				    my_capabilities : "");
368 			err = send_fetch_symrefs(ibuf, &symrefs);
369 			if (err)
370 				goto done;
371 			is_firstpkt = 0;
372 			if (!fetch_all_branches) {
373 				TAILQ_FOREACH(pe, &symrefs, entry) {
374 					const char *name = pe->path;
375 					const char *symref_target = pe->data;
376 					if (strcmp(name, GOT_REF_HEAD) != 0)
377 						continue;
378 					default_branch = symref_target;
379 					break;
380 				}
381 			}
382 			continue;
383 		}
384 		if (strstr(refname, "^{}")) {
385 			if (chattygot) {
386 				fprintf(stderr, "%s: ignoring %s\n",
387 				    getprogname(), refname);
388 			}
389 			continue;
390 		}
391 
392 		if (strncmp(refname, "refs/heads/", 11) == 0) {
393 			if (fetch_all_branches || list_refs_only) {
394 				found_branch = 1;
395 			} else if (!TAILQ_EMPTY(wanted_branches)) {
396 				TAILQ_FOREACH(pe, wanted_branches, entry) {
397 					if (match_branch(refname, pe->path))
398 						break;
399 				}
400 				if (pe == NULL) {
401 					if (chattygot) {
402 						fprintf(stderr,
403 						    "%s: ignoring %s\n",
404 						    getprogname(), refname);
405 					}
406 					continue;
407 				}
408 				found_branch = 1;
409 			} else if (default_branch != NULL) {
410 				if (!match_branch(refname, default_branch)) {
411 					if (chattygot) {
412 						fprintf(stderr,
413 						    "%s: ignoring %s\n",
414 						    getprogname(), refname);
415 					}
416 					continue;
417 				}
418 				found_branch = 1;
419 			}
420 		} else if (strncmp(refname, "refs/tags/", 10) != 0) {
421 			if (!TAILQ_EMPTY(wanted_refs)) {
422 				TAILQ_FOREACH(pe, wanted_refs, entry) {
423 					if (match_wanted_ref(refname, pe->path))
424 						break;
425 				}
426 				if (pe == NULL) {
427 					if (chattygot) {
428 						fprintf(stderr,
429 						    "%s: ignoring %s\n",
430 						    getprogname(), refname);
431 					}
432 					continue;
433 				}
434 				found_branch = 1;
435 			} else if (!list_refs_only) {
436 				if (chattygot) {
437 					fprintf(stderr, "%s: ignoring %s\n",
438 					    getprogname(), refname);
439 				}
440 				continue;
441 			}
442 		}
443 
444 		if (refsz == nref + 1) {
445 			refsz *= 2;
446 			have = reallocarray(have, refsz, sizeof(have[0]));
447 			if (have == NULL) {
448 				err = got_error_from_errno("reallocarray");
449 				goto done;
450 			}
451 			want = reallocarray(want, refsz, sizeof(want[0]));
452 			if (want == NULL) {
453 				err = got_error_from_errno("reallocarray");
454 				goto done;
455 			}
456 		}
457 		if (!got_parse_sha1_digest(want[nref].sha1, id_str)) {
458 			err = got_error(GOT_ERR_BAD_OBJ_ID_STR);
459 			goto done;
460 		}
461 		match_remote_ref(have_refs, &have[nref], refname);
462 		err = send_fetch_ref(ibuf, &want[nref], refname);
463 		if (err)
464 			goto done;
465 
466 		if (chattygot)
467 			fprintf(stderr, "%s: %s will be fetched\n",
468 			    getprogname(), refname);
469 		if (chattygot > 1) {
470 			char *theirs, *mine;
471 			err = got_object_id_str(&theirs, &want[nref]);
472 			if (err)
473 				goto done;
474 			err = got_object_id_str(&mine, &have[nref]);
475 			if (err) {
476 				free(theirs);
477 				goto done;
478 			}
479 			fprintf(stderr, "%s: remote: %s\n%s: local:  %s\n",
480 			    getprogname(), theirs, getprogname(), mine);
481 			free(theirs);
482 			free(mine);
483 		}
484 		nref++;
485 	}
486 
487 	if (list_refs_only)
488 		goto done;
489 
490 	/* Abort if we haven't found any branch to fetch. */
491 	if (!found_branch) {
492 		err = got_error(GOT_ERR_FETCH_NO_BRANCH);
493 		goto done;
494 	}
495 
496 	for (i = 0; i < nref; i++) {
497 		if (got_object_id_cmp(&have[i], &want[i]) == 0)
498 			continue;
499 		got_sha1_digest_to_str(want[i].sha1, hashstr, sizeof(hashstr));
500 		n = snprintf(buf, sizeof(buf), "want %s%s\n", hashstr,
501 		    sent_my_capabilites || my_capabilities == NULL ?
502 		    "" : my_capabilities);
503 		if (n >= sizeof(buf)) {
504 			err = got_error(GOT_ERR_NO_SPACE);
505 			goto done;
506 		}
507 		err = got_pkt_writepkt(fd, buf, n, chattygot);
508 		if (err)
509 			goto done;
510 		sent_my_capabilites = 1;
511 		nwant++;
512 	}
513 	err = got_pkt_flushpkt(fd, chattygot);
514 	if (err)
515 		goto done;
516 
517 	if (nwant == 0)
518 		goto done;
519 
520 	TAILQ_FOREACH(pe, have_refs, entry) {
521 		struct got_object_id *id = pe->data;
522 		got_sha1_digest_to_str(id->sha1, hashstr, sizeof(hashstr));
523 		n = snprintf(buf, sizeof(buf), "have %s\n", hashstr);
524 		if (n >= sizeof(buf)) {
525 			err = got_error(GOT_ERR_NO_SPACE);
526 			goto done;
527 		}
528 		err = got_pkt_writepkt(fd, buf, n, chattygot);
529 		if (err)
530 			goto done;
531 		nhave++;
532 	}
533 
534 	while (nhave > 0 && !acked) {
535 		struct got_object_id common_id;
536 
537 		/* The server should ACK the object IDs we need. */
538 		err = got_pkt_readpkt(&n, fd, buf, sizeof(buf), chattygot);
539 		if (err)
540 			goto done;
541 		if (n >= 4 && strncmp(buf, "ERR ", 4) == 0) {
542 			err = fetch_error(&buf[4], n - 4);
543 			goto done;
544 		}
545 		if (n >= 4 && strncmp(buf, "NAK\n", 4) == 0) {
546 			/* Server has not located our objects yet. */
547 			continue;
548 		}
549 		if (n < 4 + SHA1_DIGEST_STRING_LENGTH ||
550 		    strncmp(buf, "ACK ", 4) != 0) {
551 			err = got_error_msg(GOT_ERR_BAD_PACKET,
552 			    "unexpected message from server");
553 			goto done;
554 		}
555 		if (!got_parse_sha1_digest(common_id.sha1, buf + 4)) {
556 			err = got_error_msg(GOT_ERR_BAD_PACKET,
557 			    "bad object ID in ACK packet from server");
558 			goto done;
559 		}
560 		acked++;
561 	}
562 
563 	n = snprintf(buf, sizeof(buf), "done\n");
564 	err = got_pkt_writepkt(fd, buf, n, chattygot);
565 	if (err)
566 		goto done;
567 
568 	if (nhave == 0) {
569 		err = got_pkt_readpkt(&n, fd, buf, sizeof(buf), chattygot);
570 		if (err)
571 			goto done;
572 		if (n != 4 || strncmp(buf, "NAK\n", n) != 0) {
573 			err = got_error_msg(GOT_ERR_BAD_PACKET,
574 			    "unexpected message from server");
575 			goto done;
576 		}
577 	}
578 
579 	if (chattygot)
580 		fprintf(stderr, "%s: fetching...\n", getprogname());
581 
582 	if (my_capabilities != NULL &&
583 	    strstr(my_capabilities, GOT_CAPA_SIDE_BAND_64K) != NULL)
584 		have_sidebands = 1;
585 
586 	while (1) {
587 		ssize_t r = 0;
588 		int datalen = -1;
589 
590 		if (have_sidebands) {
591 			err = got_pkt_readhdr(&datalen, fd, chattygot);
592 			if (err)
593 				goto done;
594 			if (datalen <= 0)
595 				break;
596 
597 			/* Read sideband channel ID (one byte). */
598 			r = read(fd, buf, 1);
599 			if (r == -1) {
600 				err = got_error_from_errno("read");
601 				goto done;
602 			}
603 			if (r != 1) {
604 				err = got_error_msg(GOT_ERR_BAD_PACKET,
605 				    "short packet");
606 				goto done;
607 			}
608 			if (datalen > sizeof(buf) - 5) {
609 				err = got_error_msg(GOT_ERR_BAD_PACKET,
610 				    "bad packet length");
611 				goto done;
612 			}
613 			datalen--; /* sideband ID has been read */
614 			if (buf[0] == GOT_SIDEBAND_PACKFILE_DATA) {
615 				/* Read packfile data. */
616 				err = got_pkt_readn(&r, fd, buf, datalen);
617 				if (err)
618 					goto done;
619 				if (r != datalen) {
620 					err = got_error_msg(GOT_ERR_BAD_PACKET,
621 					    "packet too short");
622 					goto done;
623 				}
624 			} else if (buf[0] == GOT_SIDEBAND_PROGRESS_INFO) {
625 				err = got_pkt_readn(&r, fd, buf, datalen);
626 				if (err)
627 					goto done;
628 				if (r != datalen) {
629 					err = got_error_msg(GOT_ERR_BAD_PACKET,
630 					    "packet too short");
631 					goto done;
632 				}
633 				err = fetch_progress(ibuf, buf, r);
634 				if (err)
635 					goto done;
636 				continue;
637 			} else if (buf[0] == GOT_SIDEBAND_ERROR_INFO) {
638 				err = got_pkt_readn(&r, fd, buf, datalen);
639 				if (err)
640 					goto done;
641 				if (r != datalen) {
642 					err = got_error_msg(GOT_ERR_BAD_PACKET,
643 					    "packet too short");
644 					goto done;
645 				}
646 				err = fetch_error(buf, r);
647 				goto done;
648 			} else if (buf[0] == 'A') {
649 				err = got_pkt_readn(&r, fd, buf, datalen);
650 				if (err)
651 					goto done;
652 				if (r != datalen) {
653 					err = got_error_msg(GOT_ERR_BAD_PACKET,
654 					    "packet too short");
655 					goto done;
656 				}
657 				/*
658 				 * Git server responds with ACK after 'done'
659 				 * even though multi_ack is disabled?!?
660 				 */
661 				buf[r] = '\0';
662 				if (strncmp(buf, "CK ", 3) == 0)
663 					continue; /* ignore */
664 				err = got_error_msg(GOT_ERR_BAD_PACKET,
665 				    "unexpected message from server");
666 				goto done;
667 			} else {
668 				err = got_error_msg(GOT_ERR_BAD_PACKET,
669 				    "unknown side-band received from server");
670 				goto done;
671 			}
672 		} else {
673 			/* No sideband channel. Every byte is packfile data. */
674 			err = got_pkt_readn(&r, fd, buf, sizeof buf);
675 			if (err)
676 				goto done;
677 			if (r <= 0)
678 				break;
679 		}
680 
681 		/*
682 		 * An expected SHA1 checksum sits at the end of the pack file.
683 		 * Since we don't know the file size ahead of time we have to
684 		 * keep SHA1_DIGEST_LENGTH bytes buffered and avoid mixing
685 		 * those bytes into our SHA1 checksum computation until we
686 		 * know for sure that additional pack file data bytes follow.
687 		 *
688 		 * We can assume r > 0 since otherwise the loop would exit.
689 		 */
690 		if (r < SHA1_DIGEST_LENGTH) {
691 			if (sha1_buf_len < SHA1_DIGEST_LENGTH) {
692 				/*
693 				 * If there's enough buffered + read data to
694 				 * fill up the buffer then shift a sufficient
695 				 * amount of bytes out at the front to make
696 				 * room, mixing those bytes into the checksum.
697 				 */
698 				while (sha1_buf_len > 0 &&
699 				    sha1_buf_len + r > SHA1_DIGEST_LENGTH) {
700 					SHA1Update(&sha1_ctx, sha1_buf, 1);
701 					memmove(sha1_buf, sha1_buf + 1, 1);
702 					sha1_buf_len--;
703 				}
704 
705 				/* Buffer potential checksum bytes. */
706 				memcpy(sha1_buf + sha1_buf_len, buf, r);
707 				sha1_buf_len += r;
708 			} else {
709 				/*
710 				 * Mix in previously buffered bytes which
711 				 * are not part of the checksum after all.
712 				 */
713 				SHA1Update(&sha1_ctx, sha1_buf, r);
714 
715 				/* Update potential checksum buffer. */
716 				memmove(sha1_buf, sha1_buf + r,
717 				    sha1_buf_len - r);
718 				memcpy(sha1_buf + sha1_buf_len - r, buf, r);
719 			}
720 		} else {
721 			/* Mix in any previously buffered bytes. */
722 			SHA1Update(&sha1_ctx, sha1_buf, sha1_buf_len);
723 
724 			/* Mix in bytes read minus potential checksum bytes. */
725 			SHA1Update(&sha1_ctx, buf, r - SHA1_DIGEST_LENGTH);
726 
727 			/* Buffer potential checksum bytes. */
728 			memcpy(sha1_buf, buf + r - SHA1_DIGEST_LENGTH,
729 			    SHA1_DIGEST_LENGTH);
730 			sha1_buf_len = SHA1_DIGEST_LENGTH;
731 		}
732 
733 		/* Write packfile data to temporary pack file. */
734 		w = write(packfd, buf, r);
735 		if (w == -1) {
736 			err = got_error_from_errno("write");
737 			goto done;
738 		}
739 		if (w != r) {
740 			err = got_error(GOT_ERR_IO);
741 			goto done;
742 		}
743 		packsz += w;
744 
745 		/* Don't send too many progress privsep messages. */
746 		if (packsz > last_reported_packsz + 1024) {
747 			err = send_fetch_download_progress(ibuf, packsz);
748 			if (err)
749 				goto done;
750 			last_reported_packsz = packsz;
751 		}
752 	}
753 	err = send_fetch_download_progress(ibuf, packsz);
754 	if (err)
755 		goto done;
756 
757 	SHA1Final(pack_sha1, &sha1_ctx);
758 	if (sha1_buf_len != SHA1_DIGEST_LENGTH ||
759 	    memcmp(pack_sha1, sha1_buf, sha1_buf_len) != 0) {
760 		err = got_error_msg(GOT_ERR_BAD_PACKFILE,
761 		    "pack file checksum mismatch");
762 	}
763 done:
764 	TAILQ_FOREACH(pe, &symrefs, entry) {
765 		free((void *)pe->path);
766 		free(pe->data);
767 	}
768 	got_pathlist_free(&symrefs);
769 	free(have);
770 	free(want);
771 	free(id_str);
772 	free(refname);
773 	free(server_capabilities);
774 	return err;
775 }
776 
777 
778 int
779 main(int argc, char **argv)
780 {
781 	const struct got_error *err = NULL;
782 	int fetchfd, packfd = -1;
783 	uint8_t pack_sha1[SHA1_DIGEST_LENGTH];
784 	struct imsgbuf ibuf;
785 	struct imsg imsg;
786 	struct got_pathlist_head have_refs;
787 	struct got_pathlist_head wanted_branches;
788 	struct got_pathlist_head wanted_refs;
789 	struct got_pathlist_entry *pe;
790 	struct got_imsg_fetch_request fetch_req;
791 	struct got_imsg_fetch_have_ref href;
792 	struct got_imsg_fetch_wanted_branch wbranch;
793 	struct got_imsg_fetch_wanted_ref wref;
794 	size_t datalen, i;
795 #if 0
796 	static int attached;
797 	while (!attached)
798 		sleep (1);
799 #endif
800 
801 	TAILQ_INIT(&have_refs);
802 	TAILQ_INIT(&wanted_branches);
803 	TAILQ_INIT(&wanted_refs);
804 
805 	imsg_init(&ibuf, GOT_IMSG_FD_CHILD);
806 #ifndef PROFILE
807 	/* revoke access to most system calls */
808 	if (pledge("stdio recvfd", NULL) == -1) {
809 		err = got_error_from_errno("pledge");
810 		got_privsep_send_error(&ibuf, err);
811 		return 1;
812 	}
813 #endif
814 	err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
815 	if (err) {
816 		if (err->code == GOT_ERR_PRIVSEP_PIPE)
817 			err = NULL;
818 		goto done;
819 	}
820 	if (imsg.hdr.type == GOT_IMSG_STOP)
821 		goto done;
822 	if (imsg.hdr.type != GOT_IMSG_FETCH_REQUEST) {
823 		err = got_error(GOT_ERR_PRIVSEP_MSG);
824 		goto done;
825 	}
826 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
827 	if (datalen < sizeof(fetch_req)) {
828 		err = got_error(GOT_ERR_PRIVSEP_LEN);
829 		goto done;
830 	}
831 	memcpy(&fetch_req, imsg.data, sizeof(fetch_req));
832 	fetchfd = imsg.fd;
833 	imsg_free(&imsg);
834 
835 	if (fetch_req.verbosity > 0)
836 		chattygot += fetch_req.verbosity;
837 
838 	for (i = 0; i < fetch_req.n_have_refs; i++) {
839 		struct got_object_id *id;
840 		char *refname;
841 
842 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
843 		if (err) {
844 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
845 				err = NULL;
846 			goto done;
847 		}
848 		if (imsg.hdr.type == GOT_IMSG_STOP)
849 			goto done;
850 		if (imsg.hdr.type != GOT_IMSG_FETCH_HAVE_REF) {
851 			err = got_error(GOT_ERR_PRIVSEP_MSG);
852 			goto done;
853 		}
854 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
855 		if (datalen < sizeof(href)) {
856 			err = got_error(GOT_ERR_PRIVSEP_LEN);
857 			goto done;
858 		}
859 		memcpy(&href, imsg.data, sizeof(href));
860 		if (datalen - sizeof(href) < href.name_len) {
861 			err = got_error(GOT_ERR_PRIVSEP_LEN);
862 			goto done;
863 		}
864 		refname = malloc(href.name_len + 1);
865 		if (refname == NULL) {
866 			err = got_error_from_errno("malloc");
867 			goto done;
868 		}
869 		memcpy(refname, imsg.data + sizeof(href), href.name_len);
870 		refname[href.name_len] = '\0';
871 
872 		id = malloc(sizeof(*id));
873 		if (id == NULL) {
874 			free(refname);
875 			err = got_error_from_errno("malloc");
876 			goto done;
877 		}
878 		memcpy(id->sha1, href.id, SHA1_DIGEST_LENGTH);
879 		err = got_pathlist_append(&have_refs, refname, id);
880 		if (err) {
881 			free(refname);
882 			free(id);
883 			goto done;
884 		}
885 
886 		imsg_free(&imsg);
887 	}
888 
889 	for (i = 0; i < fetch_req.n_wanted_branches; i++) {
890 		char *refname;
891 
892 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
893 		if (err) {
894 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
895 				err = NULL;
896 			goto done;
897 		}
898 		if (imsg.hdr.type == GOT_IMSG_STOP)
899 			goto done;
900 		if (imsg.hdr.type != GOT_IMSG_FETCH_WANTED_BRANCH) {
901 			err = got_error(GOT_ERR_PRIVSEP_MSG);
902 			goto done;
903 		}
904 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
905 		if (datalen < sizeof(wbranch)) {
906 			err = got_error(GOT_ERR_PRIVSEP_LEN);
907 			goto done;
908 		}
909 		memcpy(&wbranch, imsg.data, sizeof(wbranch));
910 		if (datalen - sizeof(wbranch) < wbranch.name_len) {
911 			err = got_error(GOT_ERR_PRIVSEP_LEN);
912 			goto done;
913 		}
914 		refname = malloc(wbranch.name_len + 1);
915 		if (refname == NULL) {
916 			err = got_error_from_errno("malloc");
917 			goto done;
918 		}
919 		memcpy(refname, imsg.data + sizeof(wbranch), wbranch.name_len);
920 		refname[wbranch.name_len] = '\0';
921 
922 		err = got_pathlist_append(&wanted_branches, refname, NULL);
923 		if (err) {
924 			free(refname);
925 			goto done;
926 		}
927 
928 		imsg_free(&imsg);
929 	}
930 
931 	for (i = 0; i < fetch_req.n_wanted_refs; i++) {
932 		char *refname;
933 
934 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
935 		if (err) {
936 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
937 				err = NULL;
938 			goto done;
939 		}
940 		if (imsg.hdr.type == GOT_IMSG_STOP)
941 			goto done;
942 		if (imsg.hdr.type != GOT_IMSG_FETCH_WANTED_REF) {
943 			err = got_error(GOT_ERR_PRIVSEP_MSG);
944 			goto done;
945 		}
946 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
947 		if (datalen < sizeof(wref)) {
948 			err = got_error(GOT_ERR_PRIVSEP_LEN);
949 			goto done;
950 		}
951 		memcpy(&wref, imsg.data, sizeof(wref));
952 		if (datalen - sizeof(wref) < wref.name_len) {
953 			err = got_error(GOT_ERR_PRIVSEP_LEN);
954 			goto done;
955 		}
956 		refname = malloc(wref.name_len + 1);
957 		if (refname == NULL) {
958 			err = got_error_from_errno("malloc");
959 			goto done;
960 		}
961 		memcpy(refname, imsg.data + sizeof(wref), wref.name_len);
962 		refname[wref.name_len] = '\0';
963 
964 		err = got_pathlist_append(&wanted_refs, refname, NULL);
965 		if (err) {
966 			free(refname);
967 			goto done;
968 		}
969 
970 		imsg_free(&imsg);
971 	}
972 
973 	err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
974 	if (err) {
975 		if (err->code == GOT_ERR_PRIVSEP_PIPE)
976 			err = NULL;
977 		goto done;
978 	}
979 	if (imsg.hdr.type == GOT_IMSG_STOP)
980 		goto done;
981 	if (imsg.hdr.type != GOT_IMSG_FETCH_OUTFD) {
982 		err = got_error(GOT_ERR_PRIVSEP_MSG);
983 		goto done;
984 	}
985 	if (imsg.hdr.len - IMSG_HEADER_SIZE != 0) {
986 		err = got_error(GOT_ERR_PRIVSEP_LEN);
987 		goto done;
988 	}
989 	packfd = imsg.fd;
990 
991 	err = fetch_pack(fetchfd, packfd, pack_sha1, &have_refs,
992 	    fetch_req.fetch_all_branches, &wanted_branches,
993 	    &wanted_refs, fetch_req.list_refs_only, &ibuf);
994 done:
995 	TAILQ_FOREACH(pe, &have_refs, entry) {
996 		free((char *)pe->path);
997 		free(pe->data);
998 	}
999 	got_pathlist_free(&have_refs);
1000 	TAILQ_FOREACH(pe, &wanted_branches, entry)
1001 		free((char *)pe->path);
1002 	got_pathlist_free(&wanted_branches);
1003 	if (fetchfd != -1 && close(fetchfd) == -1 && err == NULL)
1004 		err = got_error_from_errno("close");
1005 	if (packfd != -1 && close(packfd) == -1 && err == NULL)
1006 		err = got_error_from_errno("close");
1007 	if (err != NULL)
1008 		got_privsep_send_error(&ibuf, err);
1009 	else
1010 		err = send_fetch_done(&ibuf, pack_sha1);
1011 	if (err != NULL) {
1012 		fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
1013 		got_privsep_send_error(&ibuf, err);
1014 	}
1015 
1016 	exit(0);
1017 }