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Date:: Wed Feb 23 13:37:13 2022 UTC
Message:: apply time-based rate-limiting to got-fetch-pack download progress output
Actions:: History | Blame | Raw File
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/uio.h>
19 #include <sys/time.h>
20 #include <sys/stat.h>
21 
22 #include <stdint.h>
23 #include <errno.h>
24 #include <limits.h>
25 #include <signal.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <ctype.h>
30 #include <fcntl.h>
31 #include <unistd.h>
32 #include <zlib.h>
33 #include <err.h>
34 
35 #include "got_compat.h"
36 
37 #include "got_error.h"
38 #include "got_object.h"
39 #include "got_path.h"
40 #include "got_version.h"
41 #include "got_fetch.h"
42 #include "got_reference.h"
43 
44 #include "got_lib_sha1.h"
45 #include "got_lib_delta.h"
46 #include "got_lib_object.h"
47 #include "got_lib_object_parse.h"
48 #include "got_lib_privsep.h"
49 #include "got_lib_pack.h"
50 #include "got_lib_pkt.h"
51 #include "got_lib_gitproto.h"
52 #include "got_lib_ratelimit.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     struct got_ratelimit *rl)
145 {
146 	const struct got_error *err;
147 	int elapsed = 0;
148 
149 	if (rl) {
150 		err = got_ratelimit_check(&elapsed, rl);
151 		if (err || !elapsed)
152 			return err;
153 	}
154 
155 	if (imsg_compose(ibuf, GOT_IMSG_FETCH_DOWNLOAD_PROGRESS, 0, 0, -1,
156 	    &bytes, sizeof(bytes)) == -1)
157 		return got_error_from_errno(
158 		    "imsg_compose FETCH_DOWNLOAD_PROGRESS");
159 
160 	return got_privsep_flush_imsg(ibuf);
161 }
162 
163 static const struct got_error *
164 send_fetch_done(struct imsgbuf *ibuf, uint8_t *pack_sha1)
165 {
166 	if (imsg_compose(ibuf, GOT_IMSG_FETCH_DONE, 0, 0, -1,
167 	    pack_sha1, SHA1_DIGEST_LENGTH) == -1)
168 		return got_error_from_errno("imsg_compose FETCH");
169 	return got_privsep_flush_imsg(ibuf);
170 }
171 
172 static const struct got_error *
173 fetch_progress(struct imsgbuf *ibuf, const char *buf, size_t len)
174 {
175 	size_t i;
176 
177 	if (len == 0)
178 		return NULL;
179 
180 	/*
181 	 * Truncate messages which exceed the maximum imsg payload size.
182 	 * Server may send up to 64k.
183 	 */
184 	if (len > MAX_IMSGSIZE - IMSG_HEADER_SIZE)
185 		len = MAX_IMSGSIZE - IMSG_HEADER_SIZE;
186 
187 	/* Only allow printable ASCII. */
188 	for (i = 0; i < len; i++) {
189 		if (isprint((unsigned char)buf[i]) ||
190 		    isspace((unsigned char)buf[i]))
191 			continue;
192 		return got_error_msg(GOT_ERR_BAD_PACKET,
193 		    "non-printable progress message received from server");
194 	}
195 
196 	return send_fetch_server_progress(ibuf, buf, len);
197 }
198 
199 static const struct got_error *
200 fetch_error(const char *buf, size_t len)
201 {
202 	static char msg[1024];
203 	size_t i;
204 
205 	for (i = 0; i < len && i < sizeof(msg) - 1; i++) {
206 		if (!isprint(buf[i]))
207 			return got_error_msg(GOT_ERR_BAD_PACKET,
208 			    "non-printable error message received from server");
209 		msg[i] = buf[i];
210 	}
211 	msg[i] = '\0';
212 	return got_error_msg(GOT_ERR_FETCH_FAILED, msg);
213 }
214 
215 static const struct got_error *
216 send_fetch_symrefs(struct imsgbuf *ibuf, struct got_pathlist_head *symrefs)
217 {
218 	const struct got_error *err = NULL;
219 	struct ibuf *wbuf;
220 	size_t len, nsymrefs = 0;
221 	struct got_pathlist_entry *pe;
222 
223 	len = sizeof(struct got_imsg_fetch_symrefs);
224 	TAILQ_FOREACH(pe, symrefs, entry) {
225 		const char *target = pe->data;
226 		len += sizeof(struct got_imsg_fetch_symref) +
227 		    pe->path_len + strlen(target);
228 		nsymrefs++;
229 	}
230 
231 	if (len >= MAX_IMSGSIZE - IMSG_HEADER_SIZE)
232 		return got_error(GOT_ERR_NO_SPACE);
233 
234 	wbuf = imsg_create(ibuf, GOT_IMSG_FETCH_SYMREFS, 0, 0, len);
235 	if (wbuf == NULL)
236 		return got_error_from_errno("imsg_create FETCH_SYMREFS");
237 
238 	/* Keep in sync with struct got_imsg_fetch_symrefs definition! */
239 	if (imsg_add(wbuf, &nsymrefs, sizeof(nsymrefs)) == -1) {
240 		err = got_error_from_errno("imsg_add FETCH_SYMREFS");
241 		ibuf_free(wbuf);
242 		return err;
243 	}
244 
245 	TAILQ_FOREACH(pe, symrefs, entry) {
246 		const char *name = pe->path;
247 		size_t name_len = pe->path_len;
248 		const char *target = pe->data;
249 		size_t target_len = strlen(target);
250 
251 		/* Keep in sync with struct got_imsg_fetch_symref definition! */
252 		if (imsg_add(wbuf, &name_len, sizeof(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_len, sizeof(target_len)) == -1) {
258 			err = got_error_from_errno("imsg_add FETCH_SYMREFS");
259 			ibuf_free(wbuf);
260 			return err;
261 		}
262 		if (imsg_add(wbuf, name, name_len) == -1) {
263 			err = got_error_from_errno("imsg_add FETCH_SYMREFS");
264 			ibuf_free(wbuf);
265 			return err;
266 		}
267 		if (imsg_add(wbuf, target, target_len) == -1) {
268 			err = got_error_from_errno("imsg_add FETCH_SYMREFS");
269 			ibuf_free(wbuf);
270 			return err;
271 		}
272 	}
273 
274 	wbuf->fd = -1;
275 	imsg_close(ibuf, wbuf);
276 	return got_privsep_flush_imsg(ibuf);
277 }
278 
279 static const struct got_error *
280 send_fetch_ref(struct imsgbuf *ibuf, struct got_object_id *refid,
281     const char *refname)
282 {
283 	const struct got_error *err = NULL;
284 	struct ibuf *wbuf;
285 	size_t len, reflen = strlen(refname);
286 
287 	len = sizeof(struct got_imsg_fetch_ref) + reflen;
288 	if (len >= MAX_IMSGSIZE - IMSG_HEADER_SIZE)
289 		return got_error(GOT_ERR_NO_SPACE);
290 
291 	wbuf = imsg_create(ibuf, GOT_IMSG_FETCH_REF, 0, 0, len);
292 	if (wbuf == NULL)
293 		return got_error_from_errno("imsg_create FETCH_REF");
294 
295 	/* Keep in sync with struct got_imsg_fetch_ref definition! */
296 	if (imsg_add(wbuf, refid->sha1, SHA1_DIGEST_LENGTH) == -1) {
297 		err = got_error_from_errno("imsg_add FETCH_REF");
298 		ibuf_free(wbuf);
299 		return err;
300 	}
301 	if (imsg_add(wbuf, refname, reflen) == -1) {
302 		err = got_error_from_errno("imsg_add FETCH_REF");
303 		ibuf_free(wbuf);
304 		return err;
305 	}
306 
307 	wbuf->fd = -1;
308 	imsg_close(ibuf, wbuf);
309 	return got_privsep_flush_imsg(ibuf);
310 }
311 
312 static const struct got_error *
313 fetch_pack(int fd, int packfd, uint8_t *pack_sha1,
314     struct got_pathlist_head *have_refs, int fetch_all_branches,
315     struct got_pathlist_head *wanted_branches,
316     struct got_pathlist_head *wanted_refs, int list_refs_only,
317     struct imsgbuf *ibuf)
318 {
319 	const struct got_error *err = NULL;
320 	char buf[GOT_PKT_MAX];
321 	char hashstr[SHA1_DIGEST_STRING_LENGTH];
322 	struct got_object_id *have, *want;
323 	int is_firstpkt = 1, nref = 0, refsz = 16;
324 	int i, n, nwant = 0, nhave = 0, acked = 0;
325 	off_t packsz = 0, last_reported_packsz = 0;
326 	char *id_str = NULL, *refname = NULL;
327 	char *server_capabilities = NULL, *my_capabilities = NULL;
328 	const char *default_branch = NULL;
329 	struct got_pathlist_head symrefs;
330 	struct got_pathlist_entry *pe;
331 	int sent_my_capabilites = 0, have_sidebands = 0;
332 	int found_branch = 0;
333 	SHA1_CTX sha1_ctx;
334 	uint8_t sha1_buf[SHA1_DIGEST_LENGTH];
335 	size_t sha1_buf_len = 0;
336 	ssize_t w;
337 	struct got_ratelimit rl;
338 
339 	TAILQ_INIT(&symrefs);
340 	SHA1Init(&sha1_ctx);
341 	got_ratelimit_init(&rl, 0, 500);
342 
343 	have = malloc(refsz * sizeof(have[0]));
344 	if (have == NULL)
345 		return got_error_from_errno("malloc");
346 	want = malloc(refsz * sizeof(want[0]));
347 	if (want == NULL) {
348 		err = got_error_from_errno("malloc");
349 		goto done;
350 	}
351 	while (1) {
352 		err = got_pkt_readpkt(&n, fd, buf, sizeof(buf), chattygot);
353 		if (err)
354 			goto done;
355 		if (n == 0)
356 			break;
357 		if (n >= 4 && strncmp(buf, "ERR ", 4) == 0) {
358 			err = fetch_error(&buf[4], n - 4);
359 			goto done;
360 		}
361 		free(id_str);
362 		free(refname);
363 		err = got_gitproto_parse_refline(&id_str, &refname,
364 		    &server_capabilities, buf, n);
365 		if (err)
366 			goto done;
367 		if (is_firstpkt) {
368 			if (chattygot && server_capabilities[0] != '\0')
369 				fprintf(stderr, "%s: server capabilities: %s\n",
370 				    getprogname(), server_capabilities);
371 			err = got_gitproto_match_capabilities(&my_capabilities,
372 			    &symrefs, server_capabilities,
373 			    got_capabilities, nitems(got_capabilities));
374 			if (err)
375 				goto done;
376 			if (chattygot)
377 				fprintf(stderr, "%s: my capabilities:%s\n",
378 				    getprogname(), my_capabilities != NULL ?
379 				    my_capabilities : "");
380 			err = send_fetch_symrefs(ibuf, &symrefs);
381 			if (err)
382 				goto done;
383 			is_firstpkt = 0;
384 			if (!fetch_all_branches) {
385 				TAILQ_FOREACH(pe, &symrefs, entry) {
386 					const char *name = pe->path;
387 					const char *symref_target = pe->data;
388 					if (strcmp(name, GOT_REF_HEAD) != 0)
389 						continue;
390 					default_branch = symref_target;
391 					break;
392 				}
393 			}
394 			continue;
395 		}
396 		if (strstr(refname, "^{}")) {
397 			if (chattygot) {
398 				fprintf(stderr, "%s: ignoring %s\n",
399 				    getprogname(), refname);
400 			}
401 			continue;
402 		}
403 
404 		if (strncmp(refname, "refs/heads/", 11) == 0) {
405 			if (fetch_all_branches || list_refs_only) {
406 				found_branch = 1;
407 			} else if (!TAILQ_EMPTY(wanted_branches)) {
408 				TAILQ_FOREACH(pe, wanted_branches, entry) {
409 					if (match_branch(refname, pe->path))
410 						break;
411 				}
412 				if (pe == NULL) {
413 					if (chattygot) {
414 						fprintf(stderr,
415 						    "%s: ignoring %s\n",
416 						    getprogname(), refname);
417 					}
418 					continue;
419 				}
420 				found_branch = 1;
421 			} else if (default_branch != NULL) {
422 				if (!match_branch(refname, default_branch)) {
423 					if (chattygot) {
424 						fprintf(stderr,
425 						    "%s: ignoring %s\n",
426 						    getprogname(), refname);
427 					}
428 					continue;
429 				}
430 				found_branch = 1;
431 			}
432 		} else if (strncmp(refname, "refs/tags/", 10) != 0) {
433 			if (!TAILQ_EMPTY(wanted_refs)) {
434 				TAILQ_FOREACH(pe, wanted_refs, entry) {
435 					if (match_wanted_ref(refname, pe->path))
436 						break;
437 				}
438 				if (pe == NULL) {
439 					if (chattygot) {
440 						fprintf(stderr,
441 						    "%s: ignoring %s\n",
442 						    getprogname(), refname);
443 					}
444 					continue;
445 				}
446 				found_branch = 1;
447 			} else if (!list_refs_only) {
448 				if (chattygot) {
449 					fprintf(stderr, "%s: ignoring %s\n",
450 					    getprogname(), refname);
451 				}
452 				continue;
453 			}
454 		}
455 
456 		if (refsz == nref + 1) {
457 			refsz *= 2;
458 			have = reallocarray(have, refsz, sizeof(have[0]));
459 			if (have == NULL) {
460 				err = got_error_from_errno("reallocarray");
461 				goto done;
462 			}
463 			want = reallocarray(want, refsz, sizeof(want[0]));
464 			if (want == NULL) {
465 				err = got_error_from_errno("reallocarray");
466 				goto done;
467 			}
468 		}
469 		if (!got_parse_sha1_digest(want[nref].sha1, id_str)) {
470 			err = got_error(GOT_ERR_BAD_OBJ_ID_STR);
471 			goto done;
472 		}
473 		match_remote_ref(have_refs, &have[nref], refname);
474 		err = send_fetch_ref(ibuf, &want[nref], refname);
475 		if (err)
476 			goto done;
477 
478 		if (chattygot)
479 			fprintf(stderr, "%s: %s will be fetched\n",
480 			    getprogname(), refname);
481 		if (chattygot > 1) {
482 			char *theirs, *mine;
483 			err = got_object_id_str(&theirs, &want[nref]);
484 			if (err)
485 				goto done;
486 			err = got_object_id_str(&mine, &have[nref]);
487 			if (err) {
488 				free(theirs);
489 				goto done;
490 			}
491 			fprintf(stderr, "%s: remote: %s\n%s: local:  %s\n",
492 			    getprogname(), theirs, getprogname(), mine);
493 			free(theirs);
494 			free(mine);
495 		}
496 		nref++;
497 	}
498 
499 	if (list_refs_only)
500 		goto done;
501 
502 	/* Abort if we haven't found any branch to fetch. */
503 	if (!found_branch) {
504 		err = got_error(GOT_ERR_FETCH_NO_BRANCH);
505 		goto done;
506 	}
507 
508 	for (i = 0; i < nref; i++) {
509 		if (got_object_id_cmp(&have[i], &want[i]) == 0)
510 			continue;
511 		got_sha1_digest_to_str(want[i].sha1, hashstr, sizeof(hashstr));
512 		n = snprintf(buf, sizeof(buf), "want %s%s\n", hashstr,
513 		    sent_my_capabilites || my_capabilities == NULL ?
514 		    "" : my_capabilities);
515 		if (n >= sizeof(buf)) {
516 			err = got_error(GOT_ERR_NO_SPACE);
517 			goto done;
518 		}
519 		err = got_pkt_writepkt(fd, buf, n, chattygot);
520 		if (err)
521 			goto done;
522 		sent_my_capabilites = 1;
523 		nwant++;
524 	}
525 	err = got_pkt_flushpkt(fd, chattygot);
526 	if (err)
527 		goto done;
528 
529 	if (nwant == 0)
530 		goto done;
531 
532 	TAILQ_FOREACH(pe, have_refs, entry) {
533 		struct got_object_id *id = pe->data;
534 		got_sha1_digest_to_str(id->sha1, hashstr, sizeof(hashstr));
535 		n = snprintf(buf, sizeof(buf), "have %s\n", hashstr);
536 		if (n >= sizeof(buf)) {
537 			err = got_error(GOT_ERR_NO_SPACE);
538 			goto done;
539 		}
540 		err = got_pkt_writepkt(fd, buf, n, chattygot);
541 		if (err)
542 			goto done;
543 		nhave++;
544 	}
545 
546 	while (nhave > 0 && !acked) {
547 		struct got_object_id common_id;
548 
549 		/* The server should ACK the object IDs we need. */
550 		err = got_pkt_readpkt(&n, fd, buf, sizeof(buf), chattygot);
551 		if (err)
552 			goto done;
553 		if (n >= 4 && strncmp(buf, "ERR ", 4) == 0) {
554 			err = fetch_error(&buf[4], n - 4);
555 			goto done;
556 		}
557 		if (n >= 4 && strncmp(buf, "NAK\n", 4) == 0) {
558 			/* Server has not located our objects yet. */
559 			continue;
560 		}
561 		if (n < 4 + SHA1_DIGEST_STRING_LENGTH ||
562 		    strncmp(buf, "ACK ", 4) != 0) {
563 			err = got_error_msg(GOT_ERR_BAD_PACKET,
564 			    "unexpected message from server");
565 			goto done;
566 		}
567 		if (!got_parse_sha1_digest(common_id.sha1, buf + 4)) {
568 			err = got_error_msg(GOT_ERR_BAD_PACKET,
569 			    "bad object ID in ACK packet from server");
570 			goto done;
571 		}
572 		acked++;
573 	}
574 
575 	n = snprintf(buf, sizeof(buf), "done\n");
576 	err = got_pkt_writepkt(fd, buf, n, chattygot);
577 	if (err)
578 		goto done;
579 
580 	if (nhave == 0) {
581 		err = got_pkt_readpkt(&n, fd, buf, sizeof(buf), chattygot);
582 		if (err)
583 			goto done;
584 		if (n != 4 || strncmp(buf, "NAK\n", n) != 0) {
585 			err = got_error_msg(GOT_ERR_BAD_PACKET,
586 			    "unexpected message from server");
587 			goto done;
588 		}
589 	}
590 
591 	if (chattygot)
592 		fprintf(stderr, "%s: fetching...\n", getprogname());
593 
594 	if (my_capabilities != NULL &&
595 	    strstr(my_capabilities, GOT_CAPA_SIDE_BAND_64K) != NULL)
596 		have_sidebands = 1;
597 
598 	while (1) {
599 		ssize_t r = 0;
600 		int datalen = -1;
601 
602 		if (have_sidebands) {
603 			err = got_pkt_readhdr(&datalen, fd, chattygot);
604 			if (err)
605 				goto done;
606 			if (datalen <= 0)
607 				break;
608 
609 			/* Read sideband channel ID (one byte). */
610 			r = read(fd, buf, 1);
611 			if (r == -1) {
612 				err = got_error_from_errno("read");
613 				goto done;
614 			}
615 			if (r != 1) {
616 				err = got_error_msg(GOT_ERR_BAD_PACKET,
617 				    "short packet");
618 				goto done;
619 			}
620 			if (datalen > sizeof(buf) - 5) {
621 				err = got_error_msg(GOT_ERR_BAD_PACKET,
622 				    "bad packet length");
623 				goto done;
624 			}
625 			datalen--; /* sideband ID has been read */
626 			if (buf[0] == GOT_SIDEBAND_PACKFILE_DATA) {
627 				/* Read packfile data. */
628 				err = got_pkt_readn(&r, fd, buf, datalen);
629 				if (err)
630 					goto done;
631 				if (r != datalen) {
632 					err = got_error_msg(GOT_ERR_BAD_PACKET,
633 					    "packet too short");
634 					goto done;
635 				}
636 			} else if (buf[0] == GOT_SIDEBAND_PROGRESS_INFO) {
637 				err = got_pkt_readn(&r, fd, buf, datalen);
638 				if (err)
639 					goto done;
640 				if (r != datalen) {
641 					err = got_error_msg(GOT_ERR_BAD_PACKET,
642 					    "packet too short");
643 					goto done;
644 				}
645 				err = fetch_progress(ibuf, buf, r);
646 				if (err)
647 					goto done;
648 				continue;
649 			} else if (buf[0] == GOT_SIDEBAND_ERROR_INFO) {
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 				err = fetch_error(buf, r);
659 				goto done;
660 			} else if (buf[0] == 'A') {
661 				err = got_pkt_readn(&r, fd, buf, datalen);
662 				if (err)
663 					goto done;
664 				if (r != datalen) {
665 					err = got_error_msg(GOT_ERR_BAD_PACKET,
666 					    "packet too short");
667 					goto done;
668 				}
669 				/*
670 				 * Git server responds with ACK after 'done'
671 				 * even though multi_ack is disabled?!?
672 				 */
673 				buf[r] = '\0';
674 				if (strncmp(buf, "CK ", 3) == 0)
675 					continue; /* ignore */
676 				err = got_error_msg(GOT_ERR_BAD_PACKET,
677 				    "unexpected message from server");
678 				goto done;
679 			} else {
680 				err = got_error_msg(GOT_ERR_BAD_PACKET,
681 				    "unknown side-band received from server");
682 				goto done;
683 			}
684 		} else {
685 			/* No sideband channel. Every byte is packfile data. */
686 			err = got_pkt_readn(&r, fd, buf, sizeof buf);
687 			if (err)
688 				goto done;
689 			if (r <= 0)
690 				break;
691 		}
692 
693 		/*
694 		 * An expected SHA1 checksum sits at the end of the pack file.
695 		 * Since we don't know the file size ahead of time we have to
696 		 * keep SHA1_DIGEST_LENGTH bytes buffered and avoid mixing
697 		 * those bytes into our SHA1 checksum computation until we
698 		 * know for sure that additional pack file data bytes follow.
699 		 *
700 		 * We can assume r > 0 since otherwise the loop would exit.
701 		 */
702 		if (r < SHA1_DIGEST_LENGTH) {
703 			if (sha1_buf_len < SHA1_DIGEST_LENGTH) {
704 				/*
705 				 * If there's enough buffered + read data to
706 				 * fill up the buffer then shift a sufficient
707 				 * amount of bytes out at the front to make
708 				 * room, mixing those bytes into the checksum.
709 				 */
710 				while (sha1_buf_len > 0 &&
711 				    sha1_buf_len + r > SHA1_DIGEST_LENGTH) {
712 					SHA1Update(&sha1_ctx, sha1_buf, 1);
713 					memmove(sha1_buf, sha1_buf + 1, 1);
714 					sha1_buf_len--;
715 				}
716 
717 				/* Buffer potential checksum bytes. */
718 				memcpy(sha1_buf + sha1_buf_len, buf, r);
719 				sha1_buf_len += r;
720 			} else {
721 				/*
722 				 * Mix in previously buffered bytes which
723 				 * are not part of the checksum after all.
724 				 */
725 				SHA1Update(&sha1_ctx, sha1_buf, r);
726 
727 				/* Update potential checksum buffer. */
728 				memmove(sha1_buf, sha1_buf + r,
729 				    sha1_buf_len - r);
730 				memcpy(sha1_buf + sha1_buf_len - r, buf, r);
731 			}
732 		} else {
733 			/* Mix in any previously buffered bytes. */
734 			SHA1Update(&sha1_ctx, sha1_buf, sha1_buf_len);
735 
736 			/* Mix in bytes read minus potential checksum bytes. */
737 			SHA1Update(&sha1_ctx, buf, r - SHA1_DIGEST_LENGTH);
738 
739 			/* Buffer potential checksum bytes. */
740 			memcpy(sha1_buf, buf + r - SHA1_DIGEST_LENGTH,
741 			    SHA1_DIGEST_LENGTH);
742 			sha1_buf_len = SHA1_DIGEST_LENGTH;
743 		}
744 
745 		/* Write packfile data to temporary pack file. */
746 		w = write(packfd, buf, r);
747 		if (w == -1) {
748 			err = got_error_from_errno("write");
749 			goto done;
750 		}
751 		if (w != r) {
752 			err = got_error(GOT_ERR_IO);
753 			goto done;
754 		}
755 		packsz += w;
756 
757 		/* Don't send too many progress privsep messages. */
758 		if (packsz > last_reported_packsz + 1024) {
759 			err = send_fetch_download_progress(ibuf, packsz, &rl);
760 			if (err)
761 				goto done;
762 			last_reported_packsz = packsz;
763 		}
764 	}
765 	err = send_fetch_download_progress(ibuf, packsz, NULL);
766 	if (err)
767 		goto done;
768 
769 	SHA1Final(pack_sha1, &sha1_ctx);
770 	if (sha1_buf_len != SHA1_DIGEST_LENGTH ||
771 	    memcmp(pack_sha1, sha1_buf, sha1_buf_len) != 0) {
772 		err = got_error_msg(GOT_ERR_BAD_PACKFILE,
773 		    "pack file checksum mismatch");
774 	}
775 done:
776 	TAILQ_FOREACH(pe, &symrefs, entry) {
777 		free((void *)pe->path);
778 		free(pe->data);
779 	}
780 	got_pathlist_free(&symrefs);
781 	free(have);
782 	free(want);
783 	free(id_str);
784 	free(refname);
785 	free(server_capabilities);
786 	return err;
787 }
788 
789 
790 int
791 main(int argc, char **argv)
792 {
793 	const struct got_error *err = NULL;
794 	int fetchfd, packfd = -1;
795 	uint8_t pack_sha1[SHA1_DIGEST_LENGTH];
796 	struct imsgbuf ibuf;
797 	struct imsg imsg;
798 	struct got_pathlist_head have_refs;
799 	struct got_pathlist_head wanted_branches;
800 	struct got_pathlist_head wanted_refs;
801 	struct got_pathlist_entry *pe;
802 	struct got_imsg_fetch_request fetch_req;
803 	struct got_imsg_fetch_have_ref href;
804 	struct got_imsg_fetch_wanted_branch wbranch;
805 	struct got_imsg_fetch_wanted_ref wref;
806 	size_t datalen, i;
807 #if 0
808 	static int attached;
809 	while (!attached)
810 		sleep (1);
811 #endif
812 
813 	TAILQ_INIT(&have_refs);
814 	TAILQ_INIT(&wanted_branches);
815 	TAILQ_INIT(&wanted_refs);
816 
817 	imsg_init(&ibuf, GOT_IMSG_FD_CHILD);
818 #ifndef PROFILE
819 	/* revoke access to most system calls */
820 	if (pledge("stdio recvfd", NULL) == -1) {
821 		err = got_error_from_errno("pledge");
822 		got_privsep_send_error(&ibuf, err);
823 		return 1;
824 	}
825 
826 	/* revoke fs access */
827 	if (landlock_no_fs() == -1) {
828 		err = got_error_from_errno("landlock_no_fs");
829 		got_privsep_send_error(&ibuf, err);
830 		return 1;
831 	}
832 #endif
833 	err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
834 	if (err) {
835 		if (err->code == GOT_ERR_PRIVSEP_PIPE)
836 			err = NULL;
837 		goto done;
838 	}
839 	if (imsg.hdr.type == GOT_IMSG_STOP)
840 		goto done;
841 	if (imsg.hdr.type != GOT_IMSG_FETCH_REQUEST) {
842 		err = got_error(GOT_ERR_PRIVSEP_MSG);
843 		goto done;
844 	}
845 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
846 	if (datalen < sizeof(fetch_req)) {
847 		err = got_error(GOT_ERR_PRIVSEP_LEN);
848 		goto done;
849 	}
850 	memcpy(&fetch_req, imsg.data, sizeof(fetch_req));
851 	fetchfd = imsg.fd;
852 	imsg_free(&imsg);
853 
854 	if (fetch_req.verbosity > 0)
855 		chattygot += fetch_req.verbosity;
856 
857 	for (i = 0; i < fetch_req.n_have_refs; i++) {
858 		struct got_object_id *id;
859 		char *refname;
860 
861 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
862 		if (err) {
863 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
864 				err = NULL;
865 			goto done;
866 		}
867 		if (imsg.hdr.type == GOT_IMSG_STOP)
868 			goto done;
869 		if (imsg.hdr.type != GOT_IMSG_FETCH_HAVE_REF) {
870 			err = got_error(GOT_ERR_PRIVSEP_MSG);
871 			goto done;
872 		}
873 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
874 		if (datalen < sizeof(href)) {
875 			err = got_error(GOT_ERR_PRIVSEP_LEN);
876 			goto done;
877 		}
878 		memcpy(&href, imsg.data, sizeof(href));
879 		if (datalen - sizeof(href) < href.name_len) {
880 			err = got_error(GOT_ERR_PRIVSEP_LEN);
881 			goto done;
882 		}
883 		refname = malloc(href.name_len + 1);
884 		if (refname == NULL) {
885 			err = got_error_from_errno("malloc");
886 			goto done;
887 		}
888 		memcpy(refname, imsg.data + sizeof(href), href.name_len);
889 		refname[href.name_len] = '\0';
890 
891 		id = malloc(sizeof(*id));
892 		if (id == NULL) {
893 			free(refname);
894 			err = got_error_from_errno("malloc");
895 			goto done;
896 		}
897 		memcpy(id->sha1, href.id, SHA1_DIGEST_LENGTH);
898 		err = got_pathlist_append(&have_refs, refname, id);
899 		if (err) {
900 			free(refname);
901 			free(id);
902 			goto done;
903 		}
904 
905 		imsg_free(&imsg);
906 	}
907 
908 	for (i = 0; i < fetch_req.n_wanted_branches; i++) {
909 		char *refname;
910 
911 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
912 		if (err) {
913 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
914 				err = NULL;
915 			goto done;
916 		}
917 		if (imsg.hdr.type == GOT_IMSG_STOP)
918 			goto done;
919 		if (imsg.hdr.type != GOT_IMSG_FETCH_WANTED_BRANCH) {
920 			err = got_error(GOT_ERR_PRIVSEP_MSG);
921 			goto done;
922 		}
923 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
924 		if (datalen < sizeof(wbranch)) {
925 			err = got_error(GOT_ERR_PRIVSEP_LEN);
926 			goto done;
927 		}
928 		memcpy(&wbranch, imsg.data, sizeof(wbranch));
929 		if (datalen - sizeof(wbranch) < wbranch.name_len) {
930 			err = got_error(GOT_ERR_PRIVSEP_LEN);
931 			goto done;
932 		}
933 		refname = malloc(wbranch.name_len + 1);
934 		if (refname == NULL) {
935 			err = got_error_from_errno("malloc");
936 			goto done;
937 		}
938 		memcpy(refname, imsg.data + sizeof(wbranch), wbranch.name_len);
939 		refname[wbranch.name_len] = '\0';
940 
941 		err = got_pathlist_append(&wanted_branches, refname, NULL);
942 		if (err) {
943 			free(refname);
944 			goto done;
945 		}
946 
947 		imsg_free(&imsg);
948 	}
949 
950 	for (i = 0; i < fetch_req.n_wanted_refs; i++) {
951 		char *refname;
952 
953 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
954 		if (err) {
955 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
956 				err = NULL;
957 			goto done;
958 		}
959 		if (imsg.hdr.type == GOT_IMSG_STOP)
960 			goto done;
961 		if (imsg.hdr.type != GOT_IMSG_FETCH_WANTED_REF) {
962 			err = got_error(GOT_ERR_PRIVSEP_MSG);
963 			goto done;
964 		}
965 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
966 		if (datalen < sizeof(wref)) {
967 			err = got_error(GOT_ERR_PRIVSEP_LEN);
968 			goto done;
969 		}
970 		memcpy(&wref, imsg.data, sizeof(wref));
971 		if (datalen - sizeof(wref) < wref.name_len) {
972 			err = got_error(GOT_ERR_PRIVSEP_LEN);
973 			goto done;
974 		}
975 		refname = malloc(wref.name_len + 1);
976 		if (refname == NULL) {
977 			err = got_error_from_errno("malloc");
978 			goto done;
979 		}
980 		memcpy(refname, imsg.data + sizeof(wref), wref.name_len);
981 		refname[wref.name_len] = '\0';
982 
983 		err = got_pathlist_append(&wanted_refs, refname, NULL);
984 		if (err) {
985 			free(refname);
986 			goto done;
987 		}
988 
989 		imsg_free(&imsg);
990 	}
991 
992 	err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
993 	if (err) {
994 		if (err->code == GOT_ERR_PRIVSEP_PIPE)
995 			err = NULL;
996 		goto done;
997 	}
998 	if (imsg.hdr.type == GOT_IMSG_STOP)
999 		goto done;
1000 	if (imsg.hdr.type != GOT_IMSG_FETCH_OUTFD) {
1001 		err = got_error(GOT_ERR_PRIVSEP_MSG);
1002 		goto done;
1003 	}
1004 	if (imsg.hdr.len - IMSG_HEADER_SIZE != 0) {
1005 		err = got_error(GOT_ERR_PRIVSEP_LEN);
1006 		goto done;
1007 	}
1008 	packfd = imsg.fd;
1009 
1010 	err = fetch_pack(fetchfd, packfd, pack_sha1, &have_refs,
1011 	    fetch_req.fetch_all_branches, &wanted_branches,
1012 	    &wanted_refs, fetch_req.list_refs_only, &ibuf);
1013 done:
1014 	TAILQ_FOREACH(pe, &have_refs, entry) {
1015 		free((char *)pe->path);
1016 		free(pe->data);
1017 	}
1018 	got_pathlist_free(&have_refs);
1019 	TAILQ_FOREACH(pe, &wanted_branches, entry)
1020 		free((char *)pe->path);
1021 	got_pathlist_free(&wanted_branches);
1022 	if (fetchfd != -1 && close(fetchfd) == -1 && err == NULL)
1023 		err = got_error_from_errno("close");
1024 	if (packfd != -1 && close(packfd) == -1 && err == NULL)
1025 		err = got_error_from_errno("close");
1026 	if (err != NULL)
1027 		got_privsep_send_error(&ibuf, err);
1028 	else
1029 		err = send_fetch_done(&ibuf, pack_sha1);
1030 	if (err != NULL) {
1031 		fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
1032 		got_privsep_send_error(&ibuf, err);
1033 	}
1034 
1035 	exit(0);
1036 }