Got Mirror

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Date:: Tue Feb 14 12:51:29 2023 UTC
Message:: got: always fetch remote HEAD except when -b is used Rather than only fetch HEAD when there are no branches set in got.conf and there is no branch to be inferred from a work tree, or said branches don't exist on the server, always fetch HEAD unless 'got fetch -b branch' is used. ok stsp@
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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 #include "got_lib_ratelimit.h"
54 
55 #ifndef MIN
56 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
57 #endif
58 
59 #ifndef nitems
60 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
61 #endif
62 
63 struct got_object *indexed;
64 static int chattygot;
65 
66 static const struct got_capability got_capabilities[] = {
67 	{ GOT_CAPA_AGENT, "got/" GOT_VERSION_STR },
68 	{ GOT_CAPA_OFS_DELTA, NULL },
69 	{ GOT_CAPA_SIDE_BAND_64K, NULL },
70 };
71 
72 static void
73 match_remote_ref(struct got_pathlist_head *have_refs,
74     struct got_object_id *my_id, const char *refname)
75 {
76 	struct got_pathlist_entry *pe;
77 
78 	/* XXX zero-hash signifies we don't have this ref;
79 	 * we should use a flag instead */
80 	memset(my_id, 0, sizeof(*my_id));
81 
82 	TAILQ_FOREACH(pe, have_refs, entry) {
83 		struct got_object_id *id = pe->data;
84 		if (strcmp(pe->path, refname) == 0) {
85 			memcpy(my_id, id, sizeof(*my_id));
86 			break;
87 		}
88 	}
89 }
90 
91 static int
92 match_branch(const char *branch, const char *wanted_branch)
93 {
94 	if (strncmp(branch, "refs/heads/", 11) != 0)
95 		return 0;
96 
97 	if (strncmp(wanted_branch, "refs/heads/", 11) == 0)
98 		wanted_branch += 11;
99 
100 	return (strcmp(branch + 11, wanted_branch) == 0);
101 }
102 
103 static int
104 match_wanted_ref(const char *refname, const char *wanted_ref)
105 {
106 	if (strncmp(refname, "refs/", 5) != 0)
107 		return 0;
108 	refname += 5;
109 
110 	/*
111 	 * Prevent fetching of references that won't make any
112 	 * sense outside of the remote repository's context.
113 	 */
114 	if (strncmp(refname, "got/", 4) == 0)
115 		return 0;
116 	if (strncmp(refname, "remotes/", 8) == 0)
117 		return 0;
118 
119 	if (strncmp(wanted_ref, "refs/", 5) == 0)
120 		wanted_ref += 5;
121 
122 	/* Allow prefix match. */
123 	if (got_path_is_child(refname, wanted_ref, strlen(wanted_ref)))
124 		return 1;
125 
126 	/* Allow exact match. */
127 	return (strcmp(refname, wanted_ref) == 0);
128 }
129 
130 static const struct got_error *
131 send_fetch_server_progress(struct imsgbuf *ibuf, const char *msg, size_t msglen)
132 {
133 	if (msglen > MAX_IMSGSIZE - IMSG_HEADER_SIZE)
134 		return got_error(GOT_ERR_NO_SPACE);
135 
136 	if (msglen == 0)
137 		return NULL;
138 
139 	if (imsg_compose(ibuf, GOT_IMSG_FETCH_SERVER_PROGRESS, 0, 0, -1,
140 	    msg, msglen) == -1)
141 		return got_error_from_errno(
142 		    "imsg_compose FETCH_SERVER_PROGRESS");
143 
144 	return got_privsep_flush_imsg(ibuf);
145 }
146 
147 static const struct got_error *
148 send_fetch_download_progress(struct imsgbuf *ibuf, off_t bytes,
149     struct got_ratelimit *rl)
150 {
151 	const struct got_error *err;
152 	int elapsed = 0;
153 
154 	if (rl) {
155 		err = got_ratelimit_check(&elapsed, rl);
156 		if (err || !elapsed)
157 			return err;
158 	}
159 
160 	if (imsg_compose(ibuf, GOT_IMSG_FETCH_DOWNLOAD_PROGRESS, 0, 0, -1,
161 	    &bytes, sizeof(bytes)) == -1)
162 		return got_error_from_errno(
163 		    "imsg_compose FETCH_DOWNLOAD_PROGRESS");
164 
165 	return got_privsep_flush_imsg(ibuf);
166 }
167 
168 static const struct got_error *
169 send_fetch_done(struct imsgbuf *ibuf, uint8_t *pack_sha1)
170 {
171 	if (imsg_compose(ibuf, GOT_IMSG_FETCH_DONE, 0, 0, -1,
172 	    pack_sha1, SHA1_DIGEST_LENGTH) == -1)
173 		return got_error_from_errno("imsg_compose FETCH");
174 	return got_privsep_flush_imsg(ibuf);
175 }
176 
177 static const struct got_error *
178 fetch_progress(struct imsgbuf *ibuf, const char *buf, size_t len)
179 {
180 	size_t i;
181 
182 	if (len == 0)
183 		return NULL;
184 
185 	/*
186 	 * Truncate messages which exceed the maximum imsg payload size.
187 	 * Server may send up to 64k.
188 	 */
189 	if (len > MAX_IMSGSIZE - IMSG_HEADER_SIZE)
190 		len = MAX_IMSGSIZE - IMSG_HEADER_SIZE;
191 
192 	/* Only allow printable ASCII. */
193 	for (i = 0; i < len; i++) {
194 		if (isprint((unsigned char)buf[i]) ||
195 		    isspace((unsigned char)buf[i]))
196 			continue;
197 		return got_error_msg(GOT_ERR_BAD_PACKET,
198 		    "non-printable progress message received from server");
199 	}
200 
201 	return send_fetch_server_progress(ibuf, buf, len);
202 }
203 
204 static const struct got_error *
205 fetch_error(const char *buf, size_t len)
206 {
207 	static char msg[1024];
208 	size_t i;
209 
210 	for (i = 0; i < len && i < sizeof(msg) - 1; i++) {
211 		if (!isprint((unsigned char)buf[i]))
212 			return got_error_msg(GOT_ERR_BAD_PACKET,
213 			    "non-printable error message received from server");
214 		msg[i] = buf[i];
215 	}
216 	msg[i] = '\0';
217 	return got_error_msg(GOT_ERR_FETCH_FAILED, msg);
218 }
219 
220 static const struct got_error *
221 send_fetch_symrefs(struct imsgbuf *ibuf, struct got_pathlist_head *symrefs)
222 {
223 	struct ibuf *wbuf;
224 	size_t len, nsymrefs = 0;
225 	struct got_pathlist_entry *pe;
226 
227 	len = sizeof(struct got_imsg_fetch_symrefs);
228 	TAILQ_FOREACH(pe, symrefs, entry) {
229 		const char *target = pe->data;
230 		len += sizeof(struct got_imsg_fetch_symref) +
231 		    pe->path_len + strlen(target);
232 		nsymrefs++;
233 	}
234 
235 	if (len >= MAX_IMSGSIZE - IMSG_HEADER_SIZE)
236 		return got_error(GOT_ERR_NO_SPACE);
237 
238 	wbuf = imsg_create(ibuf, GOT_IMSG_FETCH_SYMREFS, 0, 0, len);
239 	if (wbuf == NULL)
240 		return got_error_from_errno("imsg_create FETCH_SYMREFS");
241 
242 	/* Keep in sync with struct got_imsg_fetch_symrefs definition! */
243 	if (imsg_add(wbuf, &nsymrefs, sizeof(nsymrefs)) == -1)
244 		return got_error_from_errno("imsg_add FETCH_SYMREFS");
245 
246 	TAILQ_FOREACH(pe, symrefs, entry) {
247 		const char *name = pe->path;
248 		size_t name_len = pe->path_len;
249 		const char *target = pe->data;
250 		size_t target_len = strlen(target);
251 
252 		/* Keep in sync with struct got_imsg_fetch_symref definition! */
253 		if (imsg_add(wbuf, &name_len, sizeof(name_len)) == -1)
254 			return got_error_from_errno("imsg_add FETCH_SYMREFS");
255 		if (imsg_add(wbuf, &target_len, sizeof(target_len)) == -1)
256 			return got_error_from_errno("imsg_add FETCH_SYMREFS");
257 		if (imsg_add(wbuf, name, name_len) == -1)
258 			return got_error_from_errno("imsg_add FETCH_SYMREFS");
259 		if (imsg_add(wbuf, target, target_len) == -1)
260 			return got_error_from_errno("imsg_add FETCH_SYMREFS");
261 	}
262 
263 	wbuf->fd = -1;
264 	imsg_close(ibuf, wbuf);
265 	return got_privsep_flush_imsg(ibuf);
266 }
267 
268 static const struct got_error *
269 send_fetch_ref(struct imsgbuf *ibuf, struct got_object_id *refid,
270     const char *refname)
271 {
272 	struct ibuf *wbuf;
273 	size_t len, reflen = strlen(refname);
274 
275 	len = sizeof(struct got_imsg_fetch_ref) + reflen;
276 	if (len >= MAX_IMSGSIZE - IMSG_HEADER_SIZE)
277 		return got_error(GOT_ERR_NO_SPACE);
278 
279 	wbuf = imsg_create(ibuf, GOT_IMSG_FETCH_REF, 0, 0, len);
280 	if (wbuf == NULL)
281 		return got_error_from_errno("imsg_create FETCH_REF");
282 
283 	/* Keep in sync with struct got_imsg_fetch_ref definition! */
284 	if (imsg_add(wbuf, refid, sizeof(*refid)) == -1)
285 		return got_error_from_errno("imsg_add FETCH_REF");
286 	if (imsg_add(wbuf, refname, reflen) == -1)
287 		return got_error_from_errno("imsg_add FETCH_REF");
288 
289 	wbuf->fd = -1;
290 	imsg_close(ibuf, wbuf);
291 	return got_privsep_flush_imsg(ibuf);
292 }
293 
294 static const struct got_error *
295 fetch_ref(struct imsgbuf *ibuf, struct got_pathlist_head *have_refs,
296     struct got_object_id *have, struct got_object_id *want,
297     const char *refname, const char *id_str)
298 {
299 	const struct got_error *err;
300 	char *theirs = NULL, *mine = NULL;
301 
302 	if (!got_parse_sha1_digest(want->sha1, id_str)) {
303 		err = got_error(GOT_ERR_BAD_OBJ_ID_STR);
304 		goto done;
305 	}
306 
307 	match_remote_ref(have_refs, have, refname);
308 	err = send_fetch_ref(ibuf, want, refname);
309 	if (err)
310 		goto done;
311 
312 	if (chattygot)
313 		fprintf(stderr, "%s: %s will be fetched\n",
314 		    getprogname(), refname);
315 	if (chattygot > 1) {
316 		err = got_object_id_str(&theirs, want);
317 		if (err)
318 			goto done;
319 		err = got_object_id_str(&mine, have);
320 		if (err)
321 			goto done;
322 		fprintf(stderr, "%s: remote: %s\n%s: local:  %s\n",
323 		    getprogname(), theirs, getprogname(), mine);
324 	}
325 done:
326 	free(theirs);
327 	free(mine);
328 	return err;
329 }
330 
331 static const struct got_error *
332 fetch_pack(int fd, int packfd, uint8_t *pack_sha1,
333     struct got_pathlist_head *have_refs, int fetch_all_branches,
334     struct got_pathlist_head *wanted_branches,
335     struct got_pathlist_head *wanted_refs, int list_refs_only,
336     const char *worktree_branch, int no_head, struct imsgbuf *ibuf)
337 {
338 	const struct got_error *err = NULL;
339 	char buf[GOT_PKT_MAX];
340 	char hashstr[SHA1_DIGEST_STRING_LENGTH];
341 	struct got_object_id *have, *want;
342 	int is_firstpkt = 1, nref = 0, refsz = 16;
343 	int i, n, nwant = 0, nhave = 0, acked = 0;
344 	off_t packsz = 0, last_reported_packsz = 0;
345 	char *id_str = NULL, *refname = NULL;
346 	char *server_capabilities = NULL, *my_capabilities = NULL;
347 	const char *default_branch = NULL;
348 	struct got_pathlist_head symrefs;
349 	struct got_pathlist_entry *pe;
350 	int sent_my_capabilites = 0, have_sidebands = 0;
351 	SHA1_CTX sha1_ctx;
352 	uint8_t sha1_buf[SHA1_DIGEST_LENGTH];
353 	size_t sha1_buf_len = 0;
354 	ssize_t w;
355 	struct got_ratelimit rl;
356 
357 	TAILQ_INIT(&symrefs);
358 	SHA1Init(&sha1_ctx);
359 	got_ratelimit_init(&rl, 0, 500);
360 
361 	have = malloc(refsz * sizeof(have[0]));
362 	if (have == NULL)
363 		return got_error_from_errno("malloc");
364 	want = malloc(refsz * sizeof(want[0]));
365 	if (want == NULL) {
366 		err = got_error_from_errno("malloc");
367 		goto done;
368 	}
369 	while (1) {
370 		err = got_pkt_readpkt(&n, fd, buf, sizeof(buf), chattygot);
371 		if (err)
372 			goto done;
373 		if (n == 0)
374 			break;
375 		if (n >= 4 && strncmp(buf, "ERR ", 4) == 0) {
376 			err = fetch_error(&buf[4], n - 4);
377 			goto done;
378 		}
379 		free(id_str);
380 		free(refname);
381 		err = got_gitproto_parse_refline(&id_str, &refname,
382 		    &server_capabilities, buf, n);
383 		if (err)
384 			goto done;
385 
386 		if (refsz == nref + 1) {
387 			struct got_object_id *h, *w;
388 
389 			refsz *= 2;
390 			h = reallocarray(have, refsz, sizeof(have[0]));
391 			if (h == NULL) {
392 				err = got_error_from_errno("reallocarray");
393 				goto done;
394 			}
395 			have = h;
396 			w = reallocarray(want, refsz, sizeof(want[0]));
397 			if (w == NULL) {
398 				err = got_error_from_errno("reallocarray");
399 				goto done;
400 			}
401 			want = w;
402 		}
403 
404 		if (is_firstpkt) {
405 			if (chattygot && server_capabilities[0] != '\0')
406 				fprintf(stderr, "%s: server capabilities: %s\n",
407 				    getprogname(), server_capabilities);
408 			err = got_gitproto_match_capabilities(&my_capabilities,
409 			    &symrefs, server_capabilities,
410 			    got_capabilities, nitems(got_capabilities));
411 			if (err)
412 				goto done;
413 			if (chattygot)
414 				fprintf(stderr, "%s: my capabilities:%s\n",
415 				    getprogname(), my_capabilities != NULL ?
416 				    my_capabilities : "");
417 			err = send_fetch_symrefs(ibuf, &symrefs);
418 			if (err)
419 				goto done;
420 			is_firstpkt = 0;
421 			if (!fetch_all_branches) {
422 				TAILQ_FOREACH(pe, &symrefs, entry) {
423 					const char *name = pe->path;
424 					const char *symref_target = pe->data;
425 					if (strcmp(name, GOT_REF_HEAD) != 0)
426 						continue;
427 					default_branch = symref_target;
428 					break;
429 				}
430 			}
431 			if (default_branch)
432 				continue;
433 		}
434 		if (strstr(refname, "^{}")) {
435 			if (chattygot) {
436 				fprintf(stderr, "%s: ignoring %s\n",
437 				    getprogname(), refname);
438 			}
439 			continue;
440 		}
441 
442 		/* always fetch remote HEAD unless -b was specified */
443 		if (!no_head && default_branch &&
444 		    strcmp(refname, default_branch) == 0 &&
445 		    strncmp(default_branch, "refs/heads/", 11) == 0) {
446 			err = fetch_ref(ibuf, have_refs, &have[nref],
447 			    &want[nref], default_branch, id_str);
448 			if (err)
449 				goto done;
450 			nref++;
451 			continue;
452 		}
453 
454 		if (list_refs_only || strncmp(refname, "refs/tags/", 10) == 0) {
455 			err = fetch_ref(ibuf, have_refs, &have[nref],
456 			    &want[nref], refname, id_str);
457 			if (err)
458 				goto done;
459 			nref++;
460 		} else if (strncmp(refname, "refs/heads/", 11) == 0) {
461 			if (fetch_all_branches) {
462 				err = fetch_ref(ibuf, have_refs, &have[nref],
463 				    &want[nref], refname, id_str);
464 				if (err)
465 					goto done;
466 				nref++;
467 				continue;
468 			}
469 			TAILQ_FOREACH(pe, wanted_branches, entry) {
470 				if (match_branch(refname, pe->path))
471 					break;
472 			}
473 			if (pe != NULL || (worktree_branch != NULL &&
474 			    match_branch(refname, worktree_branch))) {
475 				err = fetch_ref(ibuf, have_refs, &have[nref],
476 				    &want[nref], refname, id_str);
477 				if (err)
478 					goto done;
479 				nref++;
480 			} else if (chattygot) {
481 				fprintf(stderr, "%s: ignoring %s\n",
482 				    getprogname(), refname);
483 			}
484 		} else {
485 			TAILQ_FOREACH(pe, wanted_refs, entry) {
486 				if (match_wanted_ref(refname, pe->path))
487 					break;
488 			}
489 			if (pe != NULL) {
490 				err = fetch_ref(ibuf, have_refs, &have[nref],
491 				    &want[nref], refname, id_str);
492 				if (err)
493 					goto done;
494 				nref++;
495 			} else if (chattygot) {
496 				fprintf(stderr, "%s: ignoring %s\n",
497 				    getprogname(), refname);
498 			}
499 		}
500 	}
501 
502 	if (list_refs_only)
503 		goto done;
504 
505 	/* Abort if we haven't found anything to fetch. */
506 	if (nref == 0) {
507 		struct got_pathlist_entry *pe;
508 		static char msg[PATH_MAX + 33];
509 
510 		pe = TAILQ_FIRST(wanted_branches);
511 		if (pe) {
512 			snprintf(msg, sizeof(msg),
513 			    "branch \"%s\" not found on server", pe->path);
514 			err = got_error_msg(GOT_ERR_FETCH_NO_BRANCH, msg);
515 			goto done;
516 		}
517 
518 		pe = TAILQ_FIRST(wanted_refs);
519 		if (pe) {
520 			snprintf(msg, sizeof(msg),
521 			    "reference \"%s\" not found on server", pe->path);
522 			err = got_error_msg(GOT_ERR_FETCH_NO_BRANCH, msg);
523 			goto done;
524 		}
525 
526 		err = got_error(GOT_ERR_FETCH_NO_BRANCH);
527 		goto done;
528 	}
529 
530 	for (i = 0; i < nref; i++) {
531 		if (got_object_id_cmp(&have[i], &want[i]) == 0)
532 			continue;
533 		got_sha1_digest_to_str(want[i].sha1, hashstr, sizeof(hashstr));
534 		n = snprintf(buf, sizeof(buf), "want %s%s\n", hashstr,
535 		    sent_my_capabilites || my_capabilities == NULL ?
536 		    "" : my_capabilities);
537 		if (n < 0 || (size_t)n >= sizeof(buf)) {
538 			err = got_error(GOT_ERR_NO_SPACE);
539 			goto done;
540 		}
541 		err = got_pkt_writepkt(fd, buf, n, chattygot);
542 		if (err)
543 			goto done;
544 		sent_my_capabilites = 1;
545 		nwant++;
546 	}
547 	err = got_pkt_flushpkt(fd, chattygot);
548 	if (err)
549 		goto done;
550 
551 	if (nwant == 0)
552 		goto done;
553 
554 	TAILQ_FOREACH(pe, have_refs, entry) {
555 		struct got_object_id *id = pe->data;
556 		got_sha1_digest_to_str(id->sha1, hashstr, sizeof(hashstr));
557 		n = snprintf(buf, sizeof(buf), "have %s\n", hashstr);
558 		if (n < 0 || (size_t)n >= sizeof(buf)) {
559 			err = got_error(GOT_ERR_NO_SPACE);
560 			goto done;
561 		}
562 		err = got_pkt_writepkt(fd, buf, n, chattygot);
563 		if (err)
564 			goto done;
565 		nhave++;
566 	}
567 
568 	while (nhave > 0 && !acked) {
569 		struct got_object_id common_id;
570 
571 		/* The server should ACK the object IDs we need. */
572 		err = got_pkt_readpkt(&n, fd, buf, sizeof(buf), chattygot);
573 		if (err)
574 			goto done;
575 		if (n >= 4 && strncmp(buf, "ERR ", 4) == 0) {
576 			err = fetch_error(&buf[4], n - 4);
577 			goto done;
578 		}
579 		if (n >= 4 && strncmp(buf, "NAK\n", 4) == 0) {
580 			/* Server has not located our objects yet. */
581 			continue;
582 		}
583 		if (n < 4 + SHA1_DIGEST_STRING_LENGTH ||
584 		    strncmp(buf, "ACK ", 4) != 0) {
585 			err = got_error_msg(GOT_ERR_BAD_PACKET,
586 			    "unexpected message from server");
587 			goto done;
588 		}
589 		if (!got_parse_sha1_digest(common_id.sha1, buf + 4)) {
590 			err = got_error_msg(GOT_ERR_BAD_PACKET,
591 			    "bad object ID in ACK packet from server");
592 			goto done;
593 		}
594 		acked++;
595 	}
596 
597 	n = strlcpy(buf, "done\n", sizeof(buf));
598 	err = got_pkt_writepkt(fd, buf, n, chattygot);
599 	if (err)
600 		goto done;
601 
602 	if (nhave == 0) {
603 		err = got_pkt_readpkt(&n, fd, buf, sizeof(buf), chattygot);
604 		if (err)
605 			goto done;
606 		if (n != 4 || strncmp(buf, "NAK\n", n) != 0) {
607 			err = got_error_msg(GOT_ERR_BAD_PACKET,
608 			    "unexpected message from server");
609 			goto done;
610 		}
611 	}
612 
613 	if (chattygot)
614 		fprintf(stderr, "%s: fetching...\n", getprogname());
615 
616 	if (my_capabilities != NULL &&
617 	    strstr(my_capabilities, GOT_CAPA_SIDE_BAND_64K) != NULL)
618 		have_sidebands = 1;
619 
620 	while (1) {
621 		ssize_t r = 0;
622 		int datalen = -1;
623 
624 		if (have_sidebands) {
625 			err = got_pkt_readhdr(&datalen, fd, chattygot);
626 			if (err)
627 				goto done;
628 			if (datalen <= 0)
629 				break;
630 
631 			/* Read sideband channel ID (one byte). */
632 			r = read(fd, buf, 1);
633 			if (r == -1) {
634 				err = got_error_from_errno("read");
635 				goto done;
636 			}
637 			if (r != 1) {
638 				err = got_error_msg(GOT_ERR_BAD_PACKET,
639 				    "short packet");
640 				goto done;
641 			}
642 			if (datalen > sizeof(buf) - 5) {
643 				err = got_error_msg(GOT_ERR_BAD_PACKET,
644 				    "bad packet length");
645 				goto done;
646 			}
647 			datalen--; /* sideband ID has been read */
648 			if (buf[0] == GOT_SIDEBAND_PACKFILE_DATA) {
649 				/* Read packfile data. */
650 				err = got_pkt_readn(&r, fd, buf, datalen);
651 				if (err)
652 					goto done;
653 				if (r != datalen) {
654 					err = got_error_msg(GOT_ERR_BAD_PACKET,
655 					    "packet too short");
656 					goto done;
657 				}
658 			} else if (buf[0] == GOT_SIDEBAND_PROGRESS_INFO) {
659 				err = got_pkt_readn(&r, fd, buf, datalen);
660 				if (err)
661 					goto done;
662 				if (r != datalen) {
663 					err = got_error_msg(GOT_ERR_BAD_PACKET,
664 					    "packet too short");
665 					goto done;
666 				}
667 				err = fetch_progress(ibuf, buf, r);
668 				if (err)
669 					goto done;
670 				continue;
671 			} else if (buf[0] == GOT_SIDEBAND_ERROR_INFO) {
672 				err = got_pkt_readn(&r, fd, buf, datalen);
673 				if (err)
674 					goto done;
675 				if (r != datalen) {
676 					err = got_error_msg(GOT_ERR_BAD_PACKET,
677 					    "packet too short");
678 					goto done;
679 				}
680 				err = fetch_error(buf, r);
681 				goto done;
682 			} else if (buf[0] == 'A') {
683 				err = got_pkt_readn(&r, fd, buf, datalen);
684 				if (err)
685 					goto done;
686 				if (r != datalen) {
687 					err = got_error_msg(GOT_ERR_BAD_PACKET,
688 					    "packet too short");
689 					goto done;
690 				}
691 				/*
692 				 * Git server responds with ACK after 'done'
693 				 * even though multi_ack is disabled?!?
694 				 */
695 				buf[r] = '\0';
696 				if (strncmp(buf, "CK ", 3) == 0)
697 					continue; /* ignore */
698 				err = got_error_msg(GOT_ERR_BAD_PACKET,
699 				    "unexpected message from server");
700 				goto done;
701 			} else {
702 				err = got_error_msg(GOT_ERR_BAD_PACKET,
703 				    "unknown side-band received from server");
704 				goto done;
705 			}
706 		} else {
707 			/* No sideband channel. Every byte is packfile data. */
708 			err = got_pkt_readn(&r, fd, buf, sizeof buf);
709 			if (err)
710 				goto done;
711 			if (r <= 0)
712 				break;
713 		}
714 
715 		/*
716 		 * An expected SHA1 checksum sits at the end of the pack file.
717 		 * Since we don't know the file size ahead of time we have to
718 		 * keep SHA1_DIGEST_LENGTH bytes buffered and avoid mixing
719 		 * those bytes into our SHA1 checksum computation until we
720 		 * know for sure that additional pack file data bytes follow.
721 		 *
722 		 * We can assume r > 0 since otherwise the loop would exit.
723 		 */
724 		if (r < SHA1_DIGEST_LENGTH) {
725 			if (sha1_buf_len < SHA1_DIGEST_LENGTH) {
726 				/*
727 				 * If there's enough buffered + read data to
728 				 * fill up the buffer then shift a sufficient
729 				 * amount of bytes out at the front to make
730 				 * room, mixing those bytes into the checksum.
731 				 */
732 				if (sha1_buf_len > 0 &&
733 				    sha1_buf_len + r > SHA1_DIGEST_LENGTH) {
734 					size_t nshift = MIN(sha1_buf_len + r -
735 					    SHA1_DIGEST_LENGTH, sha1_buf_len);
736 					SHA1Update(&sha1_ctx, sha1_buf, nshift);
737 					memmove(sha1_buf, sha1_buf + nshift,
738 					    sha1_buf_len - nshift);
739 					sha1_buf_len -= nshift;
740 				}
741 
742 				/* Buffer potential checksum bytes. */
743 				memcpy(sha1_buf + sha1_buf_len, buf, r);
744 				sha1_buf_len += r;
745 			} else {
746 				/*
747 				 * Mix in previously buffered bytes which
748 				 * are not part of the checksum after all.
749 				 */
750 				SHA1Update(&sha1_ctx, sha1_buf, r);
751 
752 				/* Update potential checksum buffer. */
753 				memmove(sha1_buf, sha1_buf + r,
754 				    sha1_buf_len - r);
755 				memcpy(sha1_buf + sha1_buf_len - r, buf, r);
756 			}
757 		} else {
758 			/* Mix in any previously buffered bytes. */
759 			SHA1Update(&sha1_ctx, sha1_buf, sha1_buf_len);
760 
761 			/* Mix in bytes read minus potential checksum bytes. */
762 			SHA1Update(&sha1_ctx, buf, r - SHA1_DIGEST_LENGTH);
763 
764 			/* Buffer potential checksum bytes. */
765 			memcpy(sha1_buf, buf + r - SHA1_DIGEST_LENGTH,
766 			    SHA1_DIGEST_LENGTH);
767 			sha1_buf_len = SHA1_DIGEST_LENGTH;
768 		}
769 
770 		/* Write packfile data to temporary pack file. */
771 		w = write(packfd, buf, r);
772 		if (w == -1) {
773 			err = got_error_from_errno("write");
774 			goto done;
775 		}
776 		if (w != r) {
777 			err = got_error(GOT_ERR_IO);
778 			goto done;
779 		}
780 		packsz += w;
781 
782 		/* Don't send too many progress privsep messages. */
783 		if (packsz > last_reported_packsz + 1024) {
784 			err = send_fetch_download_progress(ibuf, packsz, &rl);
785 			if (err)
786 				goto done;
787 			last_reported_packsz = packsz;
788 		}
789 	}
790 	err = send_fetch_download_progress(ibuf, packsz, NULL);
791 	if (err)
792 		goto done;
793 
794 	SHA1Final(pack_sha1, &sha1_ctx);
795 	if (sha1_buf_len != SHA1_DIGEST_LENGTH ||
796 	    memcmp(pack_sha1, sha1_buf, sha1_buf_len) != 0) {
797 		err = got_error_msg(GOT_ERR_BAD_PACKFILE,
798 		    "pack file checksum mismatch");
799 	}
800 done:
801 	got_pathlist_free(&symrefs, GOT_PATHLIST_FREE_ALL);
802 	free(have);
803 	free(want);
804 	free(id_str);
805 	free(refname);
806 	free(server_capabilities);
807 	return err;
808 }
809 
810 
811 int
812 main(int argc, char **argv)
813 {
814 	const struct got_error *err = NULL;
815 	int fetchfd = -1, packfd = -1;
816 	uint8_t pack_sha1[SHA1_DIGEST_LENGTH];
817 	struct imsgbuf ibuf;
818 	struct imsg imsg;
819 	struct got_pathlist_head have_refs;
820 	struct got_pathlist_head wanted_branches;
821 	struct got_pathlist_head wanted_refs;
822 	struct got_imsg_fetch_request fetch_req;
823 	struct got_imsg_fetch_have_ref href;
824 	struct got_imsg_fetch_wanted_branch wbranch;
825 	struct got_imsg_fetch_wanted_ref wref;
826 	size_t datalen, i;
827 	char *worktree_branch = NULL;
828 #if 0
829 	static int attached;
830 	while (!attached)
831 		sleep (1);
832 #endif
833 
834 	TAILQ_INIT(&have_refs);
835 	TAILQ_INIT(&wanted_branches);
836 	TAILQ_INIT(&wanted_refs);
837 
838 	imsg_init(&ibuf, GOT_IMSG_FD_CHILD);
839 #ifndef PROFILE
840 	/* revoke access to most system calls */
841 	if (pledge("stdio recvfd", NULL) == -1) {
842 		err = got_error_from_errno("pledge");
843 		got_privsep_send_error(&ibuf, err);
844 		return 1;
845 	}
846 #endif
847 	err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
848 	if (err) {
849 		if (err->code == GOT_ERR_PRIVSEP_PIPE)
850 			err = NULL;
851 		goto done;
852 	}
853 	if (imsg.hdr.type == GOT_IMSG_STOP)
854 		goto done;
855 	if (imsg.hdr.type != GOT_IMSG_FETCH_REQUEST) {
856 		err = got_error(GOT_ERR_PRIVSEP_MSG);
857 		goto done;
858 	}
859 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
860 	if (datalen < sizeof(fetch_req)) {
861 		err = got_error(GOT_ERR_PRIVSEP_LEN);
862 		goto done;
863 	}
864 	memcpy(&fetch_req, imsg.data, sizeof(fetch_req));
865 	fetchfd = imsg.fd;
866 
867 	if (datalen != sizeof(fetch_req) +
868 	    fetch_req.worktree_branch_len) {
869 		err = got_error(GOT_ERR_PRIVSEP_LEN);
870 		goto done;
871 	}
872 
873 	if (fetch_req.worktree_branch_len != 0) {
874 		worktree_branch = strndup(imsg.data +
875 		    sizeof(fetch_req), fetch_req.worktree_branch_len);
876 		if (worktree_branch == NULL) {
877 			err = got_error_from_errno("strndup");
878 			goto done;
879 		}
880 	}
881 
882 	imsg_free(&imsg);
883 
884 	if (fetch_req.verbosity > 0)
885 		chattygot += fetch_req.verbosity;
886 
887 	for (i = 0; i < fetch_req.n_have_refs; i++) {
888 		struct got_object_id *id;
889 		char *refname;
890 
891 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
892 		if (err) {
893 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
894 				err = NULL;
895 			goto done;
896 		}
897 		if (imsg.hdr.type == GOT_IMSG_STOP)
898 			goto done;
899 		if (imsg.hdr.type != GOT_IMSG_FETCH_HAVE_REF) {
900 			err = got_error(GOT_ERR_PRIVSEP_MSG);
901 			goto done;
902 		}
903 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
904 		if (datalen < sizeof(href)) {
905 			err = got_error(GOT_ERR_PRIVSEP_LEN);
906 			goto done;
907 		}
908 		memcpy(&href, imsg.data, sizeof(href));
909 		if (datalen - sizeof(href) < href.name_len) {
910 			err = got_error(GOT_ERR_PRIVSEP_LEN);
911 			goto done;
912 		}
913 		refname = strndup(imsg.data + sizeof(href), href.name_len);
914 		if (refname == NULL) {
915 			err = got_error_from_errno("strndup");
916 			goto done;
917 		}
918 
919 		id = malloc(sizeof(*id));
920 		if (id == NULL) {
921 			free(refname);
922 			err = got_error_from_errno("malloc");
923 			goto done;
924 		}
925 		memcpy(id, &href.id, sizeof(*id));
926 		err = got_pathlist_append(&have_refs, refname, id);
927 		if (err) {
928 			free(refname);
929 			free(id);
930 			goto done;
931 		}
932 
933 		imsg_free(&imsg);
934 	}
935 
936 	for (i = 0; i < fetch_req.n_wanted_branches; i++) {
937 		char *refname;
938 
939 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
940 		if (err) {
941 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
942 				err = NULL;
943 			goto done;
944 		}
945 		if (imsg.hdr.type == GOT_IMSG_STOP)
946 			goto done;
947 		if (imsg.hdr.type != GOT_IMSG_FETCH_WANTED_BRANCH) {
948 			err = got_error(GOT_ERR_PRIVSEP_MSG);
949 			goto done;
950 		}
951 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
952 		if (datalen < sizeof(wbranch)) {
953 			err = got_error(GOT_ERR_PRIVSEP_LEN);
954 			goto done;
955 		}
956 		memcpy(&wbranch, imsg.data, sizeof(wbranch));
957 		if (datalen - sizeof(wbranch) < wbranch.name_len) {
958 			err = got_error(GOT_ERR_PRIVSEP_LEN);
959 			goto done;
960 		}
961 		refname = strndup(imsg.data + sizeof(wbranch),
962 		    wbranch.name_len);
963 		if (refname == NULL) {
964 			err = got_error_from_errno("strndup");
965 			goto done;
966 		}
967 
968 		err = got_pathlist_append(&wanted_branches, refname, NULL);
969 		if (err) {
970 			free(refname);
971 			goto done;
972 		}
973 
974 		imsg_free(&imsg);
975 	}
976 
977 	for (i = 0; i < fetch_req.n_wanted_refs; i++) {
978 		char *refname;
979 
980 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
981 		if (err) {
982 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
983 				err = NULL;
984 			goto done;
985 		}
986 		if (imsg.hdr.type == GOT_IMSG_STOP)
987 			goto done;
988 		if (imsg.hdr.type != GOT_IMSG_FETCH_WANTED_REF) {
989 			err = got_error(GOT_ERR_PRIVSEP_MSG);
990 			goto done;
991 		}
992 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
993 		if (datalen < sizeof(wref)) {
994 			err = got_error(GOT_ERR_PRIVSEP_LEN);
995 			goto done;
996 		}
997 		memcpy(&wref, imsg.data, sizeof(wref));
998 		if (datalen - sizeof(wref) < wref.name_len) {
999 			err = got_error(GOT_ERR_PRIVSEP_LEN);
1000 			goto done;
1001 		}
1002 		refname = strndup(imsg.data + sizeof(wref), wref.name_len);
1003 		if (refname == NULL) {
1004 			err = got_error_from_errno("strndup");
1005 			goto done;
1006 		}
1007 
1008 		err = got_pathlist_append(&wanted_refs, refname, NULL);
1009 		if (err) {
1010 			free(refname);
1011 			goto done;
1012 		}
1013 
1014 		imsg_free(&imsg);
1015 	}
1016 
1017 	err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
1018 	if (err) {
1019 		if (err->code == GOT_ERR_PRIVSEP_PIPE)
1020 			err = NULL;
1021 		goto done;
1022 	}
1023 	if (imsg.hdr.type == GOT_IMSG_STOP)
1024 		goto done;
1025 	if (imsg.hdr.type != GOT_IMSG_FETCH_OUTFD) {
1026 		err = got_error(GOT_ERR_PRIVSEP_MSG);
1027 		goto done;
1028 	}
1029 	if (imsg.hdr.len - IMSG_HEADER_SIZE != 0) {
1030 		err = got_error(GOT_ERR_PRIVSEP_LEN);
1031 		goto done;
1032 	}
1033 	packfd = imsg.fd;
1034 
1035 	err = fetch_pack(fetchfd, packfd, pack_sha1, &have_refs,
1036 	    fetch_req.fetch_all_branches, &wanted_branches,
1037 	    &wanted_refs, fetch_req.list_refs_only,
1038 	    worktree_branch, fetch_req.no_head, &ibuf);
1039 done:
1040 	free(worktree_branch);
1041 	got_pathlist_free(&have_refs, GOT_PATHLIST_FREE_ALL);
1042 	got_pathlist_free(&wanted_branches, GOT_PATHLIST_FREE_PATH);
1043 	if (fetchfd != -1 && close(fetchfd) == -1 && err == NULL)
1044 		err = got_error_from_errno("close");
1045 	if (packfd != -1 && close(packfd) == -1 && err == NULL)
1046 		err = got_error_from_errno("close");
1047 	if (err != NULL)
1048 		got_privsep_send_error(&ibuf, err);
1049 	else
1050 		err = send_fetch_done(&ibuf, pack_sha1);
1051 	if (err != NULL) {
1052 		fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
1053 		got_privsep_send_error(&ibuf, err);
1054 	}
1055 
1056 	exit(0);
1057 }