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Date:: Wed Jan 11 08:33:41 2023 UTC
Message:: replace malloc+memcpy with strndup. no functional change intended 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, 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->sha1, SHA1_DIGEST_LENGTH) == -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_pack(int fd, int packfd, uint8_t *pack_sha1,
296     struct got_pathlist_head *have_refs, int fetch_all_branches,
297     struct got_pathlist_head *wanted_branches,
298     struct got_pathlist_head *wanted_refs, int list_refs_only,
299     struct imsgbuf *ibuf)
300 {
301 	const struct got_error *err = NULL;
302 	char buf[GOT_PKT_MAX];
303 	char hashstr[SHA1_DIGEST_STRING_LENGTH];
304 	struct got_object_id *have, *want;
305 	int is_firstpkt = 1, nref = 0, refsz = 16;
306 	int i, n, nwant = 0, nhave = 0, acked = 0;
307 	off_t packsz = 0, last_reported_packsz = 0;
308 	char *id_str = NULL, *refname = NULL;
309 	char *server_capabilities = NULL, *my_capabilities = NULL;
310 	const char *default_branch = NULL;
311 	struct got_pathlist_head symrefs;
312 	struct got_pathlist_entry *pe;
313 	int sent_my_capabilites = 0, have_sidebands = 0;
314 	int found_branch = 0;
315 	SHA1_CTX sha1_ctx;
316 	uint8_t sha1_buf[SHA1_DIGEST_LENGTH];
317 	size_t sha1_buf_len = 0;
318 	ssize_t w;
319 	struct got_ratelimit rl;
320 
321 	TAILQ_INIT(&symrefs);
322 	SHA1Init(&sha1_ctx);
323 	got_ratelimit_init(&rl, 0, 500);
324 
325 	have = malloc(refsz * sizeof(have[0]));
326 	if (have == NULL)
327 		return got_error_from_errno("malloc");
328 	want = malloc(refsz * sizeof(want[0]));
329 	if (want == NULL) {
330 		err = got_error_from_errno("malloc");
331 		goto done;
332 	}
333 	while (1) {
334 		err = got_pkt_readpkt(&n, fd, buf, sizeof(buf), chattygot);
335 		if (err)
336 			goto done;
337 		if (n == 0)
338 			break;
339 		if (n >= 4 && strncmp(buf, "ERR ", 4) == 0) {
340 			err = fetch_error(&buf[4], n - 4);
341 			goto done;
342 		}
343 		free(id_str);
344 		free(refname);
345 		err = got_gitproto_parse_refline(&id_str, &refname,
346 		    &server_capabilities, buf, n);
347 		if (err)
348 			goto done;
349 		if (is_firstpkt) {
350 			if (chattygot && server_capabilities[0] != '\0')
351 				fprintf(stderr, "%s: server capabilities: %s\n",
352 				    getprogname(), server_capabilities);
353 			err = got_gitproto_match_capabilities(&my_capabilities,
354 			    &symrefs, server_capabilities,
355 			    got_capabilities, nitems(got_capabilities));
356 			if (err)
357 				goto done;
358 			if (chattygot)
359 				fprintf(stderr, "%s: my capabilities:%s\n",
360 				    getprogname(), my_capabilities != NULL ?
361 				    my_capabilities : "");
362 			err = send_fetch_symrefs(ibuf, &symrefs);
363 			if (err)
364 				goto done;
365 			is_firstpkt = 0;
366 			if (!fetch_all_branches) {
367 				TAILQ_FOREACH(pe, &symrefs, entry) {
368 					const char *name = pe->path;
369 					const char *symref_target = pe->data;
370 					if (strcmp(name, GOT_REF_HEAD) != 0)
371 						continue;
372 					default_branch = symref_target;
373 					break;
374 				}
375 			}
376 			if (default_branch)
377 				continue;
378 		}
379 		if (strstr(refname, "^{}")) {
380 			if (chattygot) {
381 				fprintf(stderr, "%s: ignoring %s\n",
382 				    getprogname(), refname);
383 			}
384 			continue;
385 		}
386 
387 		if (strncmp(refname, "refs/heads/", 11) == 0) {
388 			if (fetch_all_branches || list_refs_only) {
389 				found_branch = 1;
390 			} else if (!TAILQ_EMPTY(wanted_branches)) {
391 				TAILQ_FOREACH(pe, wanted_branches, entry) {
392 					if (match_branch(refname, pe->path))
393 						break;
394 				}
395 				if (pe == NULL) {
396 					if (chattygot) {
397 						fprintf(stderr,
398 						    "%s: ignoring %s\n",
399 						    getprogname(), refname);
400 					}
401 					continue;
402 				}
403 				found_branch = 1;
404 			} else if (default_branch != NULL) {
405 				if (!match_branch(refname, default_branch)) {
406 					if (chattygot) {
407 						fprintf(stderr,
408 						    "%s: ignoring %s\n",
409 						    getprogname(), refname);
410 					}
411 					continue;
412 				}
413 				found_branch = 1;
414 			}
415 		} else if (strncmp(refname, "refs/tags/", 10) != 0) {
416 			if (!TAILQ_EMPTY(wanted_refs)) {
417 				TAILQ_FOREACH(pe, wanted_refs, entry) {
418 					if (match_wanted_ref(refname, pe->path))
419 						break;
420 				}
421 				if (pe == NULL) {
422 					if (chattygot) {
423 						fprintf(stderr,
424 						    "%s: ignoring %s\n",
425 						    getprogname(), refname);
426 					}
427 					continue;
428 				}
429 				found_branch = 1;
430 			} else if (!list_refs_only) {
431 				if (chattygot) {
432 					fprintf(stderr, "%s: ignoring %s\n",
433 					    getprogname(), refname);
434 				}
435 				continue;
436 			}
437 		}
438 
439 		if (refsz == nref + 1) {
440 			refsz *= 2;
441 			have = reallocarray(have, refsz, sizeof(have[0]));
442 			if (have == NULL) {
443 				err = got_error_from_errno("reallocarray");
444 				goto done;
445 			}
446 			want = reallocarray(want, refsz, sizeof(want[0]));
447 			if (want == NULL) {
448 				err = got_error_from_errno("reallocarray");
449 				goto done;
450 			}
451 		}
452 		if (!got_parse_sha1_digest(want[nref].sha1, id_str)) {
453 			err = got_error(GOT_ERR_BAD_OBJ_ID_STR);
454 			goto done;
455 		}
456 		match_remote_ref(have_refs, &have[nref], refname);
457 		err = send_fetch_ref(ibuf, &want[nref], refname);
458 		if (err)
459 			goto done;
460 
461 		if (chattygot)
462 			fprintf(stderr, "%s: %s will be fetched\n",
463 			    getprogname(), refname);
464 		if (chattygot > 1) {
465 			char *theirs, *mine;
466 			err = got_object_id_str(&theirs, &want[nref]);
467 			if (err)
468 				goto done;
469 			err = got_object_id_str(&mine, &have[nref]);
470 			if (err) {
471 				free(theirs);
472 				goto done;
473 			}
474 			fprintf(stderr, "%s: remote: %s\n%s: local:  %s\n",
475 			    getprogname(), theirs, getprogname(), mine);
476 			free(theirs);
477 			free(mine);
478 		}
479 		nref++;
480 	}
481 
482 	if (list_refs_only)
483 		goto done;
484 
485 	/* Abort if we haven't found any branch to fetch. */
486 	if (!found_branch) {
487 		err = got_error(GOT_ERR_FETCH_NO_BRANCH);
488 		goto done;
489 	}
490 
491 	for (i = 0; i < nref; i++) {
492 		if (got_object_id_cmp(&have[i], &want[i]) == 0)
493 			continue;
494 		got_sha1_digest_to_str(want[i].sha1, hashstr, sizeof(hashstr));
495 		n = snprintf(buf, sizeof(buf), "want %s%s\n", hashstr,
496 		    sent_my_capabilites || my_capabilities == NULL ?
497 		    "" : my_capabilities);
498 		if (n < 0 || (size_t)n >= sizeof(buf)) {
499 			err = got_error(GOT_ERR_NO_SPACE);
500 			goto done;
501 		}
502 		err = got_pkt_writepkt(fd, buf, n, chattygot);
503 		if (err)
504 			goto done;
505 		sent_my_capabilites = 1;
506 		nwant++;
507 	}
508 	err = got_pkt_flushpkt(fd, chattygot);
509 	if (err)
510 		goto done;
511 
512 	if (nwant == 0)
513 		goto done;
514 
515 	TAILQ_FOREACH(pe, have_refs, entry) {
516 		struct got_object_id *id = pe->data;
517 		got_sha1_digest_to_str(id->sha1, hashstr, sizeof(hashstr));
518 		n = snprintf(buf, sizeof(buf), "have %s\n", hashstr);
519 		if (n < 0 || (size_t)n >= sizeof(buf)) {
520 			err = got_error(GOT_ERR_NO_SPACE);
521 			goto done;
522 		}
523 		err = got_pkt_writepkt(fd, buf, n, chattygot);
524 		if (err)
525 			goto done;
526 		nhave++;
527 	}
528 
529 	while (nhave > 0 && !acked) {
530 		struct got_object_id common_id;
531 
532 		/* The server should ACK the object IDs we need. */
533 		err = got_pkt_readpkt(&n, fd, buf, sizeof(buf), chattygot);
534 		if (err)
535 			goto done;
536 		if (n >= 4 && strncmp(buf, "ERR ", 4) == 0) {
537 			err = fetch_error(&buf[4], n - 4);
538 			goto done;
539 		}
540 		if (n >= 4 && strncmp(buf, "NAK\n", 4) == 0) {
541 			/* Server has not located our objects yet. */
542 			continue;
543 		}
544 		if (n < 4 + SHA1_DIGEST_STRING_LENGTH ||
545 		    strncmp(buf, "ACK ", 4) != 0) {
546 			err = got_error_msg(GOT_ERR_BAD_PACKET,
547 			    "unexpected message from server");
548 			goto done;
549 		}
550 		if (!got_parse_sha1_digest(common_id.sha1, buf + 4)) {
551 			err = got_error_msg(GOT_ERR_BAD_PACKET,
552 			    "bad object ID in ACK packet from server");
553 			goto done;
554 		}
555 		acked++;
556 	}
557 
558 	n = strlcpy(buf, "done\n", sizeof(buf));
559 	err = got_pkt_writepkt(fd, buf, n, chattygot);
560 	if (err)
561 		goto done;
562 
563 	if (nhave == 0) {
564 		err = got_pkt_readpkt(&n, fd, buf, sizeof(buf), chattygot);
565 		if (err)
566 			goto done;
567 		if (n != 4 || strncmp(buf, "NAK\n", n) != 0) {
568 			err = got_error_msg(GOT_ERR_BAD_PACKET,
569 			    "unexpected message from server");
570 			goto done;
571 		}
572 	}
573 
574 	if (chattygot)
575 		fprintf(stderr, "%s: fetching...\n", getprogname());
576 
577 	if (my_capabilities != NULL &&
578 	    strstr(my_capabilities, GOT_CAPA_SIDE_BAND_64K) != NULL)
579 		have_sidebands = 1;
580 
581 	while (1) {
582 		ssize_t r = 0;
583 		int datalen = -1;
584 
585 		if (have_sidebands) {
586 			err = got_pkt_readhdr(&datalen, fd, chattygot);
587 			if (err)
588 				goto done;
589 			if (datalen <= 0)
590 				break;
591 
592 			/* Read sideband channel ID (one byte). */
593 			r = read(fd, buf, 1);
594 			if (r == -1) {
595 				err = got_error_from_errno("read");
596 				goto done;
597 			}
598 			if (r != 1) {
599 				err = got_error_msg(GOT_ERR_BAD_PACKET,
600 				    "short packet");
601 				goto done;
602 			}
603 			if (datalen > sizeof(buf) - 5) {
604 				err = got_error_msg(GOT_ERR_BAD_PACKET,
605 				    "bad packet length");
606 				goto done;
607 			}
608 			datalen--; /* sideband ID has been read */
609 			if (buf[0] == GOT_SIDEBAND_PACKFILE_DATA) {
610 				/* Read packfile data. */
611 				err = got_pkt_readn(&r, fd, buf, datalen);
612 				if (err)
613 					goto done;
614 				if (r != datalen) {
615 					err = got_error_msg(GOT_ERR_BAD_PACKET,
616 					    "packet too short");
617 					goto done;
618 				}
619 			} else if (buf[0] == GOT_SIDEBAND_PROGRESS_INFO) {
620 				err = got_pkt_readn(&r, fd, buf, datalen);
621 				if (err)
622 					goto done;
623 				if (r != datalen) {
624 					err = got_error_msg(GOT_ERR_BAD_PACKET,
625 					    "packet too short");
626 					goto done;
627 				}
628 				err = fetch_progress(ibuf, buf, r);
629 				if (err)
630 					goto done;
631 				continue;
632 			} else if (buf[0] == GOT_SIDEBAND_ERROR_INFO) {
633 				err = got_pkt_readn(&r, fd, buf, datalen);
634 				if (err)
635 					goto done;
636 				if (r != datalen) {
637 					err = got_error_msg(GOT_ERR_BAD_PACKET,
638 					    "packet too short");
639 					goto done;
640 				}
641 				err = fetch_error(buf, r);
642 				goto done;
643 			} else if (buf[0] == 'A') {
644 				err = got_pkt_readn(&r, fd, buf, datalen);
645 				if (err)
646 					goto done;
647 				if (r != datalen) {
648 					err = got_error_msg(GOT_ERR_BAD_PACKET,
649 					    "packet too short");
650 					goto done;
651 				}
652 				/*
653 				 * Git server responds with ACK after 'done'
654 				 * even though multi_ack is disabled?!?
655 				 */
656 				buf[r] = '\0';
657 				if (strncmp(buf, "CK ", 3) == 0)
658 					continue; /* ignore */
659 				err = got_error_msg(GOT_ERR_BAD_PACKET,
660 				    "unexpected message from server");
661 				goto done;
662 			} else {
663 				err = got_error_msg(GOT_ERR_BAD_PACKET,
664 				    "unknown side-band received from server");
665 				goto done;
666 			}
667 		} else {
668 			/* No sideband channel. Every byte is packfile data. */
669 			err = got_pkt_readn(&r, fd, buf, sizeof buf);
670 			if (err)
671 				goto done;
672 			if (r <= 0)
673 				break;
674 		}
675 
676 		/*
677 		 * An expected SHA1 checksum sits at the end of the pack file.
678 		 * Since we don't know the file size ahead of time we have to
679 		 * keep SHA1_DIGEST_LENGTH bytes buffered and avoid mixing
680 		 * those bytes into our SHA1 checksum computation until we
681 		 * know for sure that additional pack file data bytes follow.
682 		 *
683 		 * We can assume r > 0 since otherwise the loop would exit.
684 		 */
685 		if (r < SHA1_DIGEST_LENGTH) {
686 			if (sha1_buf_len < SHA1_DIGEST_LENGTH) {
687 				/*
688 				 * If there's enough buffered + read data to
689 				 * fill up the buffer then shift a sufficient
690 				 * amount of bytes out at the front to make
691 				 * room, mixing those bytes into the checksum.
692 				 */
693 				if (sha1_buf_len > 0 &&
694 				    sha1_buf_len + r > SHA1_DIGEST_LENGTH) {
695 					size_t nshift = MIN(sha1_buf_len + r -
696 					    SHA1_DIGEST_LENGTH, sha1_buf_len);
697 					SHA1Update(&sha1_ctx, sha1_buf, nshift);
698 					memmove(sha1_buf, sha1_buf + nshift,
699 					    sha1_buf_len - nshift);
700 					sha1_buf_len -= nshift;
701 				}
702 
703 				/* Buffer potential checksum bytes. */
704 				memcpy(sha1_buf + sha1_buf_len, buf, r);
705 				sha1_buf_len += r;
706 			} else {
707 				/*
708 				 * Mix in previously buffered bytes which
709 				 * are not part of the checksum after all.
710 				 */
711 				SHA1Update(&sha1_ctx, sha1_buf, r);
712 
713 				/* Update potential checksum buffer. */
714 				memmove(sha1_buf, sha1_buf + r,
715 				    sha1_buf_len - r);
716 				memcpy(sha1_buf + sha1_buf_len - r, buf, r);
717 			}
718 		} else {
719 			/* Mix in any previously buffered bytes. */
720 			SHA1Update(&sha1_ctx, sha1_buf, sha1_buf_len);
721 
722 			/* Mix in bytes read minus potential checksum bytes. */
723 			SHA1Update(&sha1_ctx, buf, r - SHA1_DIGEST_LENGTH);
724 
725 			/* Buffer potential checksum bytes. */
726 			memcpy(sha1_buf, buf + r - SHA1_DIGEST_LENGTH,
727 			    SHA1_DIGEST_LENGTH);
728 			sha1_buf_len = SHA1_DIGEST_LENGTH;
729 		}
730 
731 		/* Write packfile data to temporary pack file. */
732 		w = write(packfd, buf, r);
733 		if (w == -1) {
734 			err = got_error_from_errno("write");
735 			goto done;
736 		}
737 		if (w != r) {
738 			err = got_error(GOT_ERR_IO);
739 			goto done;
740 		}
741 		packsz += w;
742 
743 		/* Don't send too many progress privsep messages. */
744 		if (packsz > last_reported_packsz + 1024) {
745 			err = send_fetch_download_progress(ibuf, packsz, &rl);
746 			if (err)
747 				goto done;
748 			last_reported_packsz = packsz;
749 		}
750 	}
751 	err = send_fetch_download_progress(ibuf, packsz, NULL);
752 	if (err)
753 		goto done;
754 
755 	SHA1Final(pack_sha1, &sha1_ctx);
756 	if (sha1_buf_len != SHA1_DIGEST_LENGTH ||
757 	    memcmp(pack_sha1, sha1_buf, sha1_buf_len) != 0) {
758 		err = got_error_msg(GOT_ERR_BAD_PACKFILE,
759 		    "pack file checksum mismatch");
760 	}
761 done:
762 	got_pathlist_free(&symrefs, GOT_PATHLIST_FREE_ALL);
763 	free(have);
764 	free(want);
765 	free(id_str);
766 	free(refname);
767 	free(server_capabilities);
768 	return err;
769 }
770 
771 
772 int
773 main(int argc, char **argv)
774 {
775 	const struct got_error *err = NULL;
776 	int fetchfd = -1, packfd = -1;
777 	uint8_t pack_sha1[SHA1_DIGEST_LENGTH];
778 	struct imsgbuf ibuf;
779 	struct imsg imsg;
780 	struct got_pathlist_head have_refs;
781 	struct got_pathlist_head wanted_branches;
782 	struct got_pathlist_head wanted_refs;
783 	struct got_imsg_fetch_request fetch_req;
784 	struct got_imsg_fetch_have_ref href;
785 	struct got_imsg_fetch_wanted_branch wbranch;
786 	struct got_imsg_fetch_wanted_ref wref;
787 	size_t datalen, i;
788 #if 0
789 	static int attached;
790 	while (!attached)
791 		sleep (1);
792 #endif
793 
794 	TAILQ_INIT(&have_refs);
795 	TAILQ_INIT(&wanted_branches);
796 	TAILQ_INIT(&wanted_refs);
797 
798 	imsg_init(&ibuf, GOT_IMSG_FD_CHILD);
799 #ifndef PROFILE
800 	/* revoke access to most system calls */
801 	if (pledge("stdio recvfd", NULL) == -1) {
802 		err = got_error_from_errno("pledge");
803 		got_privsep_send_error(&ibuf, err);
804 		return 1;
805 	}
806 #endif
807 	err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
808 	if (err) {
809 		if (err->code == GOT_ERR_PRIVSEP_PIPE)
810 			err = NULL;
811 		goto done;
812 	}
813 	if (imsg.hdr.type == GOT_IMSG_STOP)
814 		goto done;
815 	if (imsg.hdr.type != GOT_IMSG_FETCH_REQUEST) {
816 		err = got_error(GOT_ERR_PRIVSEP_MSG);
817 		goto done;
818 	}
819 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
820 	if (datalen < sizeof(fetch_req)) {
821 		err = got_error(GOT_ERR_PRIVSEP_LEN);
822 		goto done;
823 	}
824 	memcpy(&fetch_req, imsg.data, sizeof(fetch_req));
825 	fetchfd = imsg.fd;
826 	imsg_free(&imsg);
827 
828 	if (fetch_req.verbosity > 0)
829 		chattygot += fetch_req.verbosity;
830 
831 	for (i = 0; i < fetch_req.n_have_refs; i++) {
832 		struct got_object_id *id;
833 		char *refname;
834 
835 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
836 		if (err) {
837 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
838 				err = NULL;
839 			goto done;
840 		}
841 		if (imsg.hdr.type == GOT_IMSG_STOP)
842 			goto done;
843 		if (imsg.hdr.type != GOT_IMSG_FETCH_HAVE_REF) {
844 			err = got_error(GOT_ERR_PRIVSEP_MSG);
845 			goto done;
846 		}
847 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
848 		if (datalen < sizeof(href)) {
849 			err = got_error(GOT_ERR_PRIVSEP_LEN);
850 			goto done;
851 		}
852 		memcpy(&href, imsg.data, sizeof(href));
853 		if (datalen - sizeof(href) < href.name_len) {
854 			err = got_error(GOT_ERR_PRIVSEP_LEN);
855 			goto done;
856 		}
857 		refname = strndup(imsg.data + sizeof(href), href.name_len);
858 		if (refname == NULL) {
859 			err = got_error_from_errno("strndup");
860 			goto done;
861 		}
862 
863 		id = malloc(sizeof(*id));
864 		if (id == NULL) {
865 			free(refname);
866 			err = got_error_from_errno("malloc");
867 			goto done;
868 		}
869 		memcpy(id->sha1, href.id, SHA1_DIGEST_LENGTH);
870 		err = got_pathlist_append(&have_refs, refname, id);
871 		if (err) {
872 			free(refname);
873 			free(id);
874 			goto done;
875 		}
876 
877 		imsg_free(&imsg);
878 	}
879 
880 	for (i = 0; i < fetch_req.n_wanted_branches; i++) {
881 		char *refname;
882 
883 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
884 		if (err) {
885 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
886 				err = NULL;
887 			goto done;
888 		}
889 		if (imsg.hdr.type == GOT_IMSG_STOP)
890 			goto done;
891 		if (imsg.hdr.type != GOT_IMSG_FETCH_WANTED_BRANCH) {
892 			err = got_error(GOT_ERR_PRIVSEP_MSG);
893 			goto done;
894 		}
895 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
896 		if (datalen < sizeof(wbranch)) {
897 			err = got_error(GOT_ERR_PRIVSEP_LEN);
898 			goto done;
899 		}
900 		memcpy(&wbranch, imsg.data, sizeof(wbranch));
901 		if (datalen - sizeof(wbranch) < wbranch.name_len) {
902 			err = got_error(GOT_ERR_PRIVSEP_LEN);
903 			goto done;
904 		}
905 		refname = strndup(imsg.data + sizeof(wbranch),
906 		    wbranch.name_len);
907 		if (refname == NULL) {
908 			err = got_error_from_errno("strndup");
909 			goto done;
910 		}
911 
912 		err = got_pathlist_append(&wanted_branches, refname, NULL);
913 		if (err) {
914 			free(refname);
915 			goto done;
916 		}
917 
918 		imsg_free(&imsg);
919 	}
920 
921 	for (i = 0; i < fetch_req.n_wanted_refs; i++) {
922 		char *refname;
923 
924 		err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
925 		if (err) {
926 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
927 				err = NULL;
928 			goto done;
929 		}
930 		if (imsg.hdr.type == GOT_IMSG_STOP)
931 			goto done;
932 		if (imsg.hdr.type != GOT_IMSG_FETCH_WANTED_REF) {
933 			err = got_error(GOT_ERR_PRIVSEP_MSG);
934 			goto done;
935 		}
936 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
937 		if (datalen < sizeof(wref)) {
938 			err = got_error(GOT_ERR_PRIVSEP_LEN);
939 			goto done;
940 		}
941 		memcpy(&wref, imsg.data, sizeof(wref));
942 		if (datalen - sizeof(wref) < wref.name_len) {
943 			err = got_error(GOT_ERR_PRIVSEP_LEN);
944 			goto done;
945 		}
946 		refname = strndup(imsg.data + sizeof(wref), wref.name_len);
947 		if (refname == NULL) {
948 			err = got_error_from_errno("strndup");
949 			goto done;
950 		}
951 
952 		err = got_pathlist_append(&wanted_refs, refname, NULL);
953 		if (err) {
954 			free(refname);
955 			goto done;
956 		}
957 
958 		imsg_free(&imsg);
959 	}
960 
961 	err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
962 	if (err) {
963 		if (err->code == GOT_ERR_PRIVSEP_PIPE)
964 			err = NULL;
965 		goto done;
966 	}
967 	if (imsg.hdr.type == GOT_IMSG_STOP)
968 		goto done;
969 	if (imsg.hdr.type != GOT_IMSG_FETCH_OUTFD) {
970 		err = got_error(GOT_ERR_PRIVSEP_MSG);
971 		goto done;
972 	}
973 	if (imsg.hdr.len - IMSG_HEADER_SIZE != 0) {
974 		err = got_error(GOT_ERR_PRIVSEP_LEN);
975 		goto done;
976 	}
977 	packfd = imsg.fd;
978 
979 	err = fetch_pack(fetchfd, packfd, pack_sha1, &have_refs,
980 	    fetch_req.fetch_all_branches, &wanted_branches,
981 	    &wanted_refs, fetch_req.list_refs_only, &ibuf);
982 done:
983 	got_pathlist_free(&have_refs, GOT_PATHLIST_FREE_ALL);
984 	got_pathlist_free(&wanted_branches, GOT_PATHLIST_FREE_PATH);
985 	if (fetchfd != -1 && close(fetchfd) == -1 && err == NULL)
986 		err = got_error_from_errno("close");
987 	if (packfd != -1 && close(packfd) == -1 && err == NULL)
988 		err = got_error_from_errno("close");
989 	if (err != NULL)
990 		got_privsep_send_error(&ibuf, err);
991 	else
992 		err = send_fetch_done(&ibuf, pack_sha1);
993 	if (err != NULL) {
994 		fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
995 		got_privsep_send_error(&ibuf, err);
996 	}
997 
998 	exit(0);
999 }