1 /*
2  * Copyright (c) 2022 Stefan Sperling <stsp@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 
21 #include <errno.h>
22 #include <event.h>
23 #include <poll.h>
24 #include <limits.h>
25 #include <sha1.h>
26 #include <sha2.h>
27 #include <stdio.h>
28 #include <stdint.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <imsg.h>
32 #include <unistd.h>
33 
34 #include "got_error.h"
35 #include "got_serve.h"
36 #include "got_path.h"
37 #include "got_version.h"
38 #include "got_reference.h"
39 #include "got_object.h"
40 
41 #include "got_lib_pkt.h"
42 #include "got_lib_dial.h"
43 #include "got_lib_gitproto.h"
44 #include "got_lib_hash.h"
45 #include "got_lib_poll.h"
46 
47 #include "gotd.h"
48 
49 #ifndef nitems
50 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
51 #endif
52 
53 static const struct got_capability read_capabilities[] = {
54 	{ GOT_CAPA_AGENT, "got/" GOT_VERSION_STR },
55 	{ GOT_CAPA_OFS_DELTA, NULL },
56 	{ GOT_CAPA_SIDE_BAND_64K, NULL },
57 };
58 
59 static const struct got_capability write_capabilities[] = {
60 	{ GOT_CAPA_AGENT, "got/" GOT_VERSION_STR },
61 	{ GOT_CAPA_OFS_DELTA, NULL },
62 	{ GOT_CAPA_REPORT_STATUS, NULL },
63 	{ GOT_CAPA_NO_THIN, NULL },
64 	{ GOT_CAPA_DELETE_REFS, NULL },
65 };
66 
67 static const struct got_error *
68 append_read_capabilities(size_t *capalen, size_t len, const char *symrefstr,
69     uint8_t *buf, size_t bufsize)
70 {
71 	struct got_capability capa[nitems(read_capabilities) + 1];
72 	size_t ncapa;
73 
74 	memcpy(&capa, read_capabilities, sizeof(read_capabilities));
75 	if (symrefstr) {
76 		capa[nitems(read_capabilities)].key = "symref";
77 		capa[nitems(read_capabilities)].value = symrefstr;
78 		ncapa = nitems(capa);
79 	} else
80 		ncapa = nitems(read_capabilities);
81 
82 	return got_gitproto_append_capabilities(capalen, buf, len,
83 	    bufsize, capa, ncapa);
84 }
85 
86 static const struct got_error *
87 send_ref(int outfd, uint8_t *id, const char *refname, int send_capabilities,
88     int client_is_reading, const char *symrefstr, int chattygot)
89 {
90 	const struct got_error *err = NULL;
91 	char hex[SHA1_DIGEST_STRING_LENGTH];
92 	char buf[GOT_PKT_MAX];
93 	size_t len, capalen = 0;
94 
95 	if (got_sha1_digest_to_str(id, hex, sizeof(hex)) == NULL)
96 		return got_error(GOT_ERR_BAD_OBJ_ID);
97 
98 	len = snprintf(buf, sizeof(buf), "%s %s", hex, refname);
99 	if (len >= sizeof(buf))
100 		return got_error(GOT_ERR_NO_SPACE);
101 
102 	if (send_capabilities) {
103 		if (client_is_reading) {
104 			err = append_read_capabilities(&capalen, len,
105 			    symrefstr, buf, sizeof(buf));
106 		} else {
107 			err = got_gitproto_append_capabilities(&capalen,
108 			    buf, len, sizeof(buf), write_capabilities,
109 			    nitems(write_capabilities));
110 		}
111 		if (err)
112 			return err;
113 		len += capalen;
114 	}
115 
116 	if (len + 1 >= sizeof(buf))
117 		return got_error(GOT_ERR_NO_SPACE);
118 	buf[len] = '\n';
119 	len++;
120 	buf[len] = '\0';
121 
122 	return got_pkt_writepkt(outfd, buf, len, chattygot);
123 }
124 
125 static const struct got_error *
126 send_zero_refs(int outfd, int client_is_reading, int chattygot)
127 {
128 	const struct got_error *err = NULL;
129 	const char *line = GOT_SHA1_STRING_ZERO " capabilities^{}";
130 	char buf[GOT_PKT_MAX];
131 	size_t len, capalen = 0;
132 
133 	len = strlcpy(buf, line, sizeof(buf));
134 	if (len >= sizeof(buf))
135 		return got_error(GOT_ERR_NO_SPACE);
136 
137 	if (client_is_reading) {
138 		err = got_gitproto_append_capabilities(&capalen, buf, len,
139 		    sizeof(buf), read_capabilities, nitems(read_capabilities));
140 		if (err)
141 			return err;
142 	} else {
143 		err = got_gitproto_append_capabilities(&capalen, buf, len,
144 		    sizeof(buf), write_capabilities,
145 		    nitems(write_capabilities));
146 		if (err)
147 			return err;
148 	}
149 
150 	return got_pkt_writepkt(outfd, buf, len + capalen, chattygot);
151 }
152 
153 static void
154 echo_error(const struct got_error *err, int outfd, int chattygot)
155 {
156 	char buf[4 + GOT_ERR_MAX_MSG_SIZE];
157 	size_t len;
158 
159 	/*
160 	 * Echo the error to the client on a pkt-line.
161 	 * The client should then terminate its session.
162 	 */
163 	buf[0] = 'E'; buf[1] = 'R'; buf[2] = 'R'; buf[3] = ' '; buf[4] = '\0';
164 	len = strlcat(buf, err->msg, sizeof(buf));
165 	got_pkt_writepkt(outfd, buf, len, chattygot);
166 }
167 
168 static const struct got_error *
169 announce_refs(int outfd, struct imsgbuf *ibuf, int client_is_reading,
170     const char *repo_path, int chattygot)
171 {
172 	const struct got_error *err = NULL;
173 	struct imsg imsg;
174 	size_t datalen;
175 	struct gotd_imsg_list_refs lsref;
176 	struct gotd_imsg_reflist ireflist;
177 	struct gotd_imsg_ref iref;
178 	struct gotd_imsg_symref isymref;
179 	size_t nrefs = 0;
180 	int have_nrefs = 0, sent_capabilities = 0;
181 	char *symrefname = NULL, *symreftarget = NULL, *symrefstr = NULL;
182 	char *refname = NULL;
183 
184 	memset(&imsg, 0, sizeof(imsg));
185 	memset(&lsref, 0, sizeof(lsref));
186 
187 	if (strlcpy(lsref.repo_name, repo_path, sizeof(lsref.repo_name)) >=
188 	    sizeof(lsref.repo_name))
189 		return got_error(GOT_ERR_NO_SPACE);
190 	lsref.client_is_reading = client_is_reading;
191 
192 	if (imsg_compose(ibuf, GOTD_IMSG_LIST_REFS, 0, 0, -1,
193 	    &lsref, sizeof(lsref)) == -1)
194 		return got_error_from_errno("imsg_compose LIST_REFS");
195 
196 	err = gotd_imsg_flush(ibuf);
197 	if (err)
198 		return err;
199 
200 	while (!have_nrefs || nrefs > 0) {
201 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
202 		if (err)
203 			goto done;
204 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
205 		switch (imsg.hdr.type) {
206 		case GOTD_IMSG_ERROR:
207 			err = gotd_imsg_recv_error(NULL, &imsg);
208 			goto done;
209 		case GOTD_IMSG_REFLIST:
210 			if (have_nrefs || nrefs > 0) {
211 				err = got_error(GOT_ERR_PRIVSEP_MSG);
212 				goto done;
213 			}
214 			if (datalen != sizeof(ireflist)) {
215 				err = got_error(GOT_ERR_PRIVSEP_MSG);
216 				goto done;
217 			}
218 			memcpy(&ireflist, imsg.data, sizeof(ireflist));
219 			nrefs = ireflist.nrefs;
220 			have_nrefs = 1;
221 			if (nrefs == 0)
222 				err = send_zero_refs(outfd, client_is_reading,
223 				    chattygot);
224 			break;
225 		case GOTD_IMSG_REF:
226 			if (!have_nrefs || nrefs == 0) {
227 				err = got_error(GOT_ERR_PRIVSEP_MSG);
228 				goto done;
229 			}
230 			if (datalen < sizeof(iref)) {
231 				err = got_error(GOT_ERR_PRIVSEP_MSG);
232 				goto done;
233 			}
234 			memcpy(&iref, imsg.data, sizeof(iref));
235 			if (datalen != sizeof(iref) + iref.name_len) {
236 				err = got_error(GOT_ERR_PRIVSEP_LEN);
237 				goto done;
238 			}
239 			refname = strndup(imsg.data + sizeof(iref),
240 			    iref.name_len);
241 			if (refname == NULL) {
242 				err = got_error_from_errno("strndup");
243 				goto done;
244 			}
245 			err = send_ref(outfd, iref.id, refname,
246 			    !sent_capabilities, client_is_reading,
247 			    NULL, chattygot);
248 			free(refname);
249 			refname = NULL;
250 			if (err)
251 				goto done;
252 			sent_capabilities = 1;
253 			if (nrefs > 0)
254 				nrefs--;
255 			break;
256 		case GOTD_IMSG_SYMREF:
257 			if (!have_nrefs || nrefs == 0) {
258 				err = got_error(GOT_ERR_PRIVSEP_MSG);
259 				goto done;
260 			}
261 			if (datalen < sizeof(isymref)) {
262 				err = got_error(GOT_ERR_PRIVSEP_LEN);
263 				goto done;
264 			}
265 			memcpy(&isymref, imsg.data, sizeof(isymref));
266 			if (datalen != sizeof(isymref) + isymref.name_len +
267 			    isymref.target_len) {
268 				err = got_error(GOT_ERR_PRIVSEP_LEN);
269 				goto done;
270 			}
271 
272 			/*
273 			 * For now, we only announce one symbolic ref,
274 			 * as part of our capability advertisement.
275 			 */
276 			if (sent_capabilities || symrefstr != NULL ||
277 			    symrefname != NULL || symreftarget != NULL)
278 				break;
279 
280 			symrefname = strndup(imsg.data + sizeof(isymref),
281 			    isymref.name_len);
282 			if (symrefname == NULL) {
283 				err = got_error_from_errno("malloc");
284 				goto done;
285 			}
286 
287 			symreftarget = strndup(
288 			    imsg.data + sizeof(isymref) + isymref.name_len,
289 			    isymref.target_len);
290 			if (symreftarget == NULL) {
291 				err = got_error_from_errno("strndup");
292 				goto done;
293 			}
294 
295 			if (asprintf(&symrefstr, "%s:%s", symrefname,
296 			    symreftarget) == -1) {
297 				err = got_error_from_errno("asprintf");
298 				goto done;
299 			}
300 			err = send_ref(outfd, isymref.target_id, symrefname,
301 			    !sent_capabilities, client_is_reading, symrefstr,
302 			    chattygot);
303 			free(refname);
304 			refname = NULL;
305 			if (err)
306 				goto done;
307 			sent_capabilities = 1;
308 			if (nrefs > 0)
309 				nrefs--;
310 			break;
311 		default:
312 			err = got_error(GOT_ERR_PRIVSEP_MSG);
313 			break;
314 		}
315 
316 		imsg_free(&imsg);
317 	}
318 
319 	err = got_pkt_flushpkt(outfd, chattygot);
320 	if (err)
321 		goto done;
322 done:
323 	free(symrefstr);
324 	free(symrefname);
325 	free(symreftarget);
326 	return err;
327 }
328 
329 static const struct got_error *
330 parse_want_line(char **common_capabilities, uint8_t *id, char *buf, size_t len)
331 {
332 	const struct got_error *err;
333 	char *id_str = NULL, *client_capabilities = NULL;
334 
335 	err = got_gitproto_parse_want_line(&id_str,
336 	    &client_capabilities, buf, len);
337 	if (err)
338 		return err;
339 
340 	if (!got_parse_hash_digest(id, id_str, GOT_HASH_SHA1)) {
341 		err = got_error_msg(GOT_ERR_BAD_PACKET,
342 		    "want-line with bad object ID");
343 		goto done;
344 	}
345 
346 	if (client_capabilities) {
347 		err = got_gitproto_match_capabilities(common_capabilities,
348 		    NULL, client_capabilities, read_capabilities,
349 		    nitems(read_capabilities));
350 		if (err)
351 			goto done;
352 	}
353 done:
354 	free(id_str);
355 	free(client_capabilities);
356 	return err;
357 }
358 
359 static const struct got_error *
360 parse_have_line(uint8_t *id, char *buf, size_t len)
361 {
362 	const struct got_error *err;
363 	char *id_str = NULL;
364 
365 	err = got_gitproto_parse_have_line(&id_str, buf, len);
366 	if (err)
367 		return err;
368 
369 	if (!got_parse_hash_digest(id, id_str, GOT_HASH_SHA1)) {
370 		err = got_error_msg(GOT_ERR_BAD_PACKET,
371 		    "have-line with bad object ID");
372 		goto done;
373 	}
374 done:
375 	free(id_str);
376 	return err;
377 }
378 
379 static const struct got_error *
380 send_capability(struct got_capability *capa, struct imsgbuf *ibuf)
381 {
382 	const struct got_error *err = NULL;
383 	struct gotd_imsg_capability icapa;
384 	size_t len;
385 	struct ibuf *wbuf;
386 
387 	memset(&icapa, 0, sizeof(icapa));
388 
389 	icapa.key_len = strlen(capa->key);
390 	len = sizeof(icapa) + icapa.key_len;
391 	if (capa->value) {
392 		icapa.value_len = strlen(capa->value);
393 		len += icapa.value_len;
394 	}
395 
396 	wbuf = imsg_create(ibuf, GOTD_IMSG_CAPABILITY, 0, 0, len);
397 	if (wbuf == NULL) {
398 		err = got_error_from_errno("imsg_create CAPABILITY");
399 		return err;
400 	}
401 
402 	if (imsg_add(wbuf, &icapa, sizeof(icapa)) == -1)
403 		return got_error_from_errno("imsg_add CAPABILITY");
404 	if (imsg_add(wbuf, capa->key, icapa.key_len) == -1)
405 		return got_error_from_errno("imsg_add CAPABILITY");
406 	if (capa->value) {
407 		if (imsg_add(wbuf, capa->value, icapa.value_len) == -1)
408 			return got_error_from_errno("imsg_add CAPABILITY");
409 	}
410 
411 	imsg_close(ibuf, wbuf);
412 
413 	return NULL;
414 }
415 
416 static const struct got_error *
417 send_capabilities(int *use_sidebands, int *report_status,
418     char *capabilities_str, struct imsgbuf *ibuf)
419 {
420 	const struct got_error *err = NULL;
421 	struct gotd_imsg_capabilities icapas;
422 	struct got_capability *capa = NULL;
423 	size_t ncapa, i;
424 
425 	err = got_gitproto_split_capabilities_str(&capa, &ncapa,
426 	    capabilities_str);
427 	if (err)
428 		return err;
429 
430 	icapas.ncapabilities = ncapa;
431 	if (imsg_compose(ibuf, GOTD_IMSG_CAPABILITIES, 0, 0, -1,
432 	    &icapas, sizeof(icapas)) == -1) {
433 		err = got_error_from_errno("imsg_compose IMSG_CAPABILITIES");
434 		goto done;
435 	}
436 
437 	for (i = 0; i < ncapa; i++) {
438 		err = send_capability(&capa[i], ibuf);
439 		if (err)
440 			goto done;
441 		if (use_sidebands &&
442 		    strcmp(capa[i].key, GOT_CAPA_SIDE_BAND_64K) == 0)
443 			*use_sidebands = 1;
444 		if (report_status &&
445 		    strcmp(capa[i].key, GOT_CAPA_REPORT_STATUS) == 0)
446 			*report_status = 1;
447 	}
448 done:
449 	free(capa);
450 	return err;
451 }
452 
453 static const struct got_error *
454 forward_flushpkt(struct imsgbuf *ibuf)
455 {
456 	if (imsg_compose(ibuf, GOTD_IMSG_FLUSH, 0, 0, -1, NULL, 0) == -1)
457 		return got_error_from_errno("imsg_compose FLUSH");
458 
459 	return gotd_imsg_flush(ibuf);
460 }
461 
462 static const struct got_error *
463 recv_ack(struct imsg *imsg, uint8_t *expected_id)
464 {
465 	struct gotd_imsg_ack iack;
466 	size_t datalen;
467 
468 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
469 	if (datalen != sizeof(iack))
470 		return got_error(GOT_ERR_PRIVSEP_LEN);
471 
472 	memcpy(&iack, imsg->data, sizeof(iack));
473 	if (memcmp(iack.object_id, expected_id, SHA1_DIGEST_LENGTH) != 0)
474 		return got_error(GOT_ERR_BAD_OBJ_ID);
475 
476 	return NULL;
477 }
478 
479 static const struct got_error *
480 recv_nak(struct imsg *imsg, uint8_t *expected_id)
481 {
482 	struct gotd_imsg_ack inak;
483 	size_t datalen;
484 
485 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
486 	if (datalen != sizeof(inak))
487 		return got_error(GOT_ERR_PRIVSEP_LEN);
488 
489 	memcpy(&inak, imsg->data, sizeof(inak));
490 	if (memcmp(inak.object_id, expected_id, SHA1_DIGEST_LENGTH) != 0)
491 		return got_error(GOT_ERR_BAD_OBJ_ID);
492 
493 	return NULL;
494 }
495 
496 
497 static const struct got_error *
498 recv_want(int *use_sidebands, int outfd, struct imsgbuf *ibuf,
499     char *buf, size_t len, int expect_capabilities, int chattygot)
500 {
501 	const struct got_error *err;
502 	struct gotd_imsg_want iwant;
503 	char *capabilities_str;
504 	int done = 0;
505 	struct imsg imsg;
506 
507 	memset(&iwant, 0, sizeof(iwant));
508 	memset(&imsg, 0, sizeof(imsg));
509 
510 	err = parse_want_line(&capabilities_str, iwant.object_id, buf, len);
511 	if (err)
512 		return err;
513 
514 	if (capabilities_str) {
515 		if (!expect_capabilities) {
516 			err = got_error_msg(GOT_ERR_BAD_PACKET,
517 			    "unexpected capability announcement received");
518 			goto done;
519 		}
520 		err = send_capabilities(use_sidebands, NULL, capabilities_str,
521 		    ibuf);
522 		if (err)
523 			goto done;
524 
525 	}
526 
527 	if (imsg_compose(ibuf, GOTD_IMSG_WANT, 0, 0, -1,
528 	    &iwant, sizeof(iwant)) == -1) {
529 		err = got_error_from_errno("imsg_compose WANT");
530 		goto done;
531 	}
532 
533 	err = gotd_imsg_flush(ibuf);
534 	if (err)
535 		goto done;
536 
537 	/*
538 	 * Wait for an ACK, or an error in case the desired object
539 	 * does not exist.
540 	 */
541 	while (!done && err == NULL) {
542 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
543 		if (err)
544 			break;
545 		switch (imsg.hdr.type) {
546 		case GOTD_IMSG_ERROR:
547 			err = gotd_imsg_recv_error(NULL, &imsg);
548 			break;
549 		case GOTD_IMSG_ACK:
550 			err = recv_ack(&imsg, iwant.object_id);
551 			if (err)
552 				break;
553 			done = 1;
554 			break;
555 		default:
556 			err = got_error(GOT_ERR_PRIVSEP_MSG);
557 			break;
558 		}
559 
560 		imsg_free(&imsg);
561 	}
562 done:
563 	free(capabilities_str);
564 	return err;
565 }
566 
567 static const struct got_error *
568 send_ack(int outfd, uint8_t *id, int chattygot)
569 {
570 	char hex[SHA1_DIGEST_STRING_LENGTH];
571 	char buf[GOT_PKT_MAX];
572 	int len;
573 
574 	if (got_sha1_digest_to_str(id, hex, sizeof(hex)) == NULL)
575 		return got_error(GOT_ERR_BAD_OBJ_ID);
576 
577 	len = snprintf(buf, sizeof(buf), "ACK %s\n", hex);
578 	if (len >= sizeof(buf))
579 		return got_error(GOT_ERR_NO_SPACE);
580 
581 	return got_pkt_writepkt(outfd, buf, len, chattygot);
582 }
583 
584 static const struct got_error *
585 send_nak(int outfd, int chattygot)
586 {
587 	char buf[5];
588 	int len;
589 
590 	len = snprintf(buf, sizeof(buf), "NAK\n");
591 	if (len >= sizeof(buf))
592 		return got_error(GOT_ERR_NO_SPACE);
593 
594 	return got_pkt_writepkt(outfd, buf, len, chattygot);
595 }
596 
597 static const struct got_error *
598 recv_have(int *have_ack, int outfd, struct imsgbuf *ibuf, char *buf,
599     size_t len, int chattygot)
600 {
601 	const struct got_error *err;
602 	struct gotd_imsg_have ihave;
603 	int done = 0;
604 	struct imsg imsg;
605 
606 	memset(&ihave, 0, sizeof(ihave));
607 	memset(&imsg, 0, sizeof(imsg));
608 
609 	err = parse_have_line(ihave.object_id, buf, len);
610 	if (err)
611 		return err;
612 
613 	if (imsg_compose(ibuf, GOTD_IMSG_HAVE, 0, 0, -1,
614 	    &ihave, sizeof(ihave)) == -1)
615 		return got_error_from_errno("imsg_compose HAVE");
616 
617 	err = gotd_imsg_flush(ibuf);
618 	if (err)
619 		return err;
620 
621 	/*
622 	 * Wait for an ACK or a NAK, indicating whether a common
623 	 * commit object has been found.
624 	 */
625 	while (!done && err == NULL) {
626 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
627 		if (err)
628 			return err;
629 		switch (imsg.hdr.type) {
630 		case GOTD_IMSG_ERROR:
631 			err = gotd_imsg_recv_error(NULL, &imsg);
632 			break;
633 		case GOTD_IMSG_ACK:
634 			err = recv_ack(&imsg, ihave.object_id);
635 			if (err)
636 				break;
637 			if (!*have_ack) {
638 				err = send_ack(outfd, ihave.object_id,
639 				    chattygot);
640 				if (err)
641 					return err;
642 				*have_ack = 1;
643 			}
644 			done = 1;
645 			break;
646 		case GOTD_IMSG_NAK:
647 			err = recv_nak(&imsg, ihave.object_id);
648 			if (err)
649 				break;
650 			done = 1;
651 			break;
652 		default:
653 			err = got_error(GOT_ERR_PRIVSEP_MSG);
654 			break;
655 		}
656 
657 		imsg_free(&imsg);
658 	}
659 
660 	return err;
661 }
662 
663 static const struct got_error *
664 recv_done(int *packfd, int outfd, struct imsgbuf *ibuf, int chattygot)
665 {
666 	const struct got_error *err;
667 	struct imsg imsg;
668 	int fd;
669 
670 	*packfd = -1;
671 
672 	if (imsg_compose(ibuf, GOTD_IMSG_DONE, 0, 0, -1, NULL, 0) == -1)
673 		return got_error_from_errno("imsg_compose DONE");
674 
675 	err = gotd_imsg_flush(ibuf);
676 	if (err)
677 		return err;
678 
679 	while (*packfd == -1 && err == NULL) {
680 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
681 		if (err)
682 			break;
683 
684 		switch (imsg.hdr.type) {
685 		case GOTD_IMSG_ERROR:
686 			err = gotd_imsg_recv_error(NULL, &imsg);
687 			break;
688 		case GOTD_IMSG_PACKFILE_PIPE:
689 			fd = imsg_get_fd(&imsg);
690 			if (fd != -1)
691 				*packfd = fd;
692 			else
693 				err = got_error(GOT_ERR_PRIVSEP_NO_FD);
694 			break;
695 		default:
696 			err = got_error(GOT_ERR_PRIVSEP_MSG);
697 			break;
698 		}
699 
700 		imsg_free(&imsg);
701 	}
702 
703 	return err;
704 }
705 
706 static const struct got_error *
707 relay_progress_reports(struct imsgbuf *ibuf, int outfd, int chattygot)
708 {
709 	const struct got_error *err = NULL;
710 	int pack_starting = 0;
711 	struct gotd_imsg_packfile_progress iprog;
712 	char buf[GOT_PKT_MAX];
713 	struct imsg imsg;
714 	size_t datalen;
715 	int p_deltify = 0, n;
716 	const char *eol = "\r";
717 
718 	memset(&imsg, 0, sizeof(imsg));
719 
720 	while (!pack_starting && err == NULL) {
721 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
722 		if (err)
723 			break;
724 
725 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
726 		switch (imsg.hdr.type) {
727 		case GOTD_IMSG_ERROR:
728 			err = gotd_imsg_recv_error(NULL, &imsg);
729 			break;
730 		case GOTD_IMSG_PACKFILE_READY:
731 			eol = "\n";
732 			pack_starting = 1;
733 			/* fallthrough */
734 		case GOTD_IMSG_PACKFILE_PROGRESS:
735 			if (datalen != sizeof(iprog)) {
736 				err = got_error(GOT_ERR_PRIVSEP_LEN);
737 				break;
738 			}
739 			memcpy(&iprog, imsg.data, sizeof(iprog));
740 			if (iprog.nobj_total > 0) {
741 				p_deltify = (iprog.nobj_deltify * 100) /
742 				    iprog.nobj_total;
743 			}
744 			buf[0] = GOT_SIDEBAND_PROGRESS_INFO;
745 			n = snprintf(&buf[1], sizeof(buf) - 1,
746 			    "%d commits colored, "
747 			    "%d objects found, "
748 			    "deltify %d%%%s",
749 			    iprog.ncolored,
750 			    iprog.nfound,
751 			    p_deltify, eol);
752 			if (n >= sizeof(buf) - 1)
753 				break;
754 			err = got_pkt_writepkt(outfd, buf, 1 + n, chattygot);
755 			break;
756 		default:
757 			err = got_error(GOT_ERR_PRIVSEP_MSG);
758 			break;
759 		}
760 
761 		imsg_free(&imsg);
762 	}
763 
764 	return err;
765 }
766 
767 static const struct got_error *
768 serve_read(int infd, int outfd, int gotd_sock, const char *repo_path,
769     int chattygot)
770 {
771 	const struct got_error *err = NULL;
772 	char buf[GOT_PKT_MAX];
773 	struct imsgbuf ibuf;
774 	enum protostate {
775 		STATE_EXPECT_WANT,
776 		STATE_EXPECT_MORE_WANT,
777 		STATE_EXPECT_HAVE_OR_DONE,
778 		STATE_DONE,
779 	};
780 	enum protostate curstate = STATE_EXPECT_WANT;
781 	int have_ack = 0, use_sidebands = 0, seen_have = 0;
782 	int packfd = -1;
783 	size_t pack_chunksize;
784 
785 	imsg_init(&ibuf, gotd_sock);
786 
787 	err = announce_refs(outfd, &ibuf, 1, repo_path, chattygot);
788 	if (err)
789 		goto done;
790 
791 	while (curstate != STATE_DONE) {
792 		int n;
793 		buf[0] = '\0';
794 		err = got_pkt_readpkt(&n, infd, buf, sizeof(buf), chattygot);
795 		if (err)
796 			goto done;
797 		if (n == 0) {
798 			if (curstate != STATE_EXPECT_WANT &&
799 			    curstate != STATE_EXPECT_MORE_WANT &&
800 			    curstate != STATE_EXPECT_HAVE_OR_DONE) {
801 				err = got_error_msg(GOT_ERR_BAD_PACKET,
802 				    "unexpected flush packet received");
803 				goto done;
804 			}
805 
806 			if (curstate == STATE_EXPECT_WANT) {
807 				ssize_t r;
808 				/*
809 				 * If the client does not want to fetch
810 				 * anything we should receive a flush
811 				 * packet followed by EOF.
812 				 */
813 				r = read(infd, buf, sizeof(buf));
814 				if (r == -1) {
815 					err = got_error_from_errno("read");
816 					goto done;
817 				}
818 				if (r == 0) /* EOF */
819 					goto done;
820 
821 				/* Zero-length field followed by payload. */
822 				err = got_error_msg(GOT_ERR_BAD_PACKET,
823 				    "unexpected flush packet received");
824 				goto done;
825 			}
826 
827 			if (curstate == STATE_EXPECT_WANT ||
828 			    curstate == STATE_EXPECT_MORE_WANT ||
829 			    curstate == STATE_EXPECT_HAVE_OR_DONE) {
830 				err = forward_flushpkt(&ibuf);
831 				if (err)
832 					goto done;
833 			}
834 			if (curstate == STATE_EXPECT_HAVE_OR_DONE &&
835 			    !have_ack) {
836 				err = send_nak(outfd, chattygot);
837 				if (err)
838 					goto done;
839 			}
840 			if (curstate == STATE_EXPECT_MORE_WANT)
841 				curstate = STATE_EXPECT_HAVE_OR_DONE;
842 		} else if (n >= 5 && strncmp(buf, "want ", 5) == 0) {
843 			if (curstate != STATE_EXPECT_WANT &&
844 			    curstate != STATE_EXPECT_MORE_WANT) {
845 				err = got_error_msg(GOT_ERR_BAD_PACKET,
846 				    "unexpected 'want' packet");
847 				goto done;
848 			}
849 			err = recv_want(&use_sidebands, outfd, &ibuf, buf, n,
850 			    curstate == STATE_EXPECT_WANT ? 1 : 0, chattygot);
851 			if (err)
852 				goto done;
853 			if (curstate == STATE_EXPECT_WANT)
854 				curstate = STATE_EXPECT_MORE_WANT;
855 		} else if (n >= 5 && strncmp(buf, "have ", 5) == 0) {
856 			if (curstate != STATE_EXPECT_HAVE_OR_DONE) {
857 				err = got_error_msg(GOT_ERR_BAD_PACKET,
858 				    "unexpected 'have' packet");
859 				goto done;
860 			}
861 			err = recv_have(&have_ack, outfd, &ibuf,
862 			    buf, n, chattygot);
863 			if (err)
864 				goto done;
865 			seen_have = 1;
866 		} else if (n == 5 && strncmp(buf, "done\n", 5) == 0) {
867 			if (curstate != STATE_EXPECT_HAVE_OR_DONE) {
868 				err = got_error_msg(GOT_ERR_BAD_PACKET,
869 				    "unexpected 'done' packet");
870 				goto done;
871 			}
872 			err = recv_done(&packfd, outfd, &ibuf, chattygot);
873 			if (err)
874 				goto done;
875 			curstate = STATE_DONE;
876 			break;
877 		} else {
878 			err = got_error(GOT_ERR_BAD_PACKET);
879 			goto done;
880 		}
881 	}
882 
883 	if (!seen_have) {
884 		err = send_nak(outfd, chattygot);
885 		if (err)
886 			goto done;
887 	}
888 
889 	if (use_sidebands) {
890 		err = relay_progress_reports(&ibuf, outfd, chattygot);
891 		if (err)
892 			goto done;
893 		pack_chunksize = GOT_SIDEBAND_64K_PACKFILE_DATA_MAX;
894 	} else
895 		pack_chunksize = sizeof(buf);
896 
897 	for (;;) {
898 		ssize_t r;
899 
900 		r = read(packfd, use_sidebands ? &buf[1] : buf,
901 		    pack_chunksize);
902 		if (r == -1) {
903 			err = got_error_from_errno("read");
904 			break;
905 		} else if (r == 0) {
906 			err = got_pkt_flushpkt(outfd, chattygot);
907 			break;
908 		}
909 
910 		if (use_sidebands) {
911 			buf[0] = GOT_SIDEBAND_PACKFILE_DATA;
912 			err = got_pkt_writepkt(outfd, buf, 1 + r, chattygot);
913 			if (err)
914 				break;
915 		} else {
916 			err = got_poll_write_full(outfd, buf, r);
917 			if (err) {
918 				if (err->code == GOT_ERR_EOF)
919 					err = NULL;
920 				break;
921 			}
922 		}
923 	}
924 done:
925 	imsg_clear(&ibuf);
926 	if (packfd != -1 && close(packfd) == -1 && err == NULL)
927 		err = got_error_from_errno("close");
928 	if (err)
929 		echo_error(err, outfd, chattygot);
930 	return err;
931 }
932 
933 static const struct got_error *
934 parse_ref_update_line(char **common_capabilities, char **refname,
935     uint8_t *old_id, uint8_t *new_id, char *buf, size_t len)
936 {
937 	const struct got_error *err;
938 	char *old_id_str = NULL, *new_id_str = NULL;
939 	char *client_capabilities = NULL;
940 
941 	*refname = NULL;
942 
943 	err = got_gitproto_parse_ref_update_line(&old_id_str, &new_id_str,
944 	    refname, &client_capabilities, buf, len);
945 	if (err)
946 		return err;
947 
948 	if (!got_parse_hash_digest(old_id, old_id_str, GOT_HASH_SHA1) ||
949 	    !got_parse_hash_digest(new_id, new_id_str, GOT_HASH_SHA1)) {
950 		err = got_error_msg(GOT_ERR_BAD_PACKET,
951 		    "ref-update with bad object ID");
952 		goto done;
953 	}
954 	if (!got_ref_name_is_valid(*refname)) {
955 		err = got_error_msg(GOT_ERR_BAD_PACKET,
956 		    "ref-update with bad reference name");
957 		goto done;
958 	}
959 
960 	if (client_capabilities) {
961 		err = got_gitproto_match_capabilities(common_capabilities,
962 		    NULL, client_capabilities, write_capabilities,
963 		    nitems(write_capabilities));
964 		if (err)
965 			goto done;
966 	}
967 done:
968 	free(old_id_str);
969 	free(new_id_str);
970 	free(client_capabilities);
971 	if (err) {
972 		free(*refname);
973 		*refname = NULL;
974 	}
975 	return err;
976 }
977 
978 static const struct got_error *
979 recv_ref_update(int *report_status, int outfd, struct imsgbuf *ibuf,
980     char *buf, size_t len, int expect_capabilities, int chattygot)
981 {
982 	const struct got_error *err;
983 	struct gotd_imsg_ref_update iref;
984 	struct ibuf *wbuf;
985 	char *capabilities_str = NULL, *refname = NULL;
986 	int done = 0;
987 	struct imsg imsg;
988 
989 	memset(&iref, 0, sizeof(iref));
990 	memset(&imsg, 0, sizeof(imsg));
991 
992 	err = parse_ref_update_line(&capabilities_str, &refname,
993 	    iref.old_id, iref.new_id, buf, len);
994 	if (err)
995 		return err;
996 
997 	if (capabilities_str) {
998 		if (!expect_capabilities) {
999 			err = got_error_msg(GOT_ERR_BAD_PACKET,
1000 			    "unexpected capability announcement received");
1001 			goto done;
1002 		}
1003 		err = send_capabilities(NULL, report_status, capabilities_str,
1004 		    ibuf);
1005 		if (err)
1006 			goto done;
1007 	}
1008 
1009 	iref.name_len = strlen(refname);
1010 	len = sizeof(iref) + iref.name_len;
1011 	wbuf = imsg_create(ibuf, GOTD_IMSG_REF_UPDATE, 0, 0, len);
1012 	if (wbuf == NULL) {
1013 		err = got_error_from_errno("imsg_create REF_UPDATE");
1014 		goto done;
1015 	}
1016 
1017 	if (imsg_add(wbuf, &iref, sizeof(iref)) == -1)
1018 		return got_error_from_errno("imsg_add REF_UPDATE");
1019 	if (imsg_add(wbuf, refname, iref.name_len) == -1)
1020 		return got_error_from_errno("imsg_add REF_UPDATE");
1021 	imsg_close(ibuf, wbuf);
1022 
1023 	err = gotd_imsg_flush(ibuf);
1024 	if (err)
1025 		goto done;
1026 
1027 	/* Wait for ACK or an error. */
1028 	while (!done && err == NULL) {
1029 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
1030 		if (err)
1031 			break;
1032 		switch (imsg.hdr.type) {
1033 		case GOTD_IMSG_ERROR:
1034 			err = gotd_imsg_recv_error(NULL, &imsg);
1035 			break;
1036 		case GOTD_IMSG_ACK:
1037 			err = recv_ack(&imsg, iref.new_id);
1038 			if (err)
1039 				break;
1040 			done = 1;
1041 			break;
1042 		default:
1043 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1044 			break;
1045 		}
1046 
1047 		imsg_free(&imsg);
1048 	}
1049 done:
1050 	free(capabilities_str);
1051 	free(refname);
1052 	return err;
1053 }
1054 
1055 static const struct got_error *
1056 recv_packfile(struct imsg *imsg, int infd)
1057 {
1058 	const struct got_error *err = NULL;
1059 	size_t datalen;
1060 	int packfd;
1061 	char buf[GOT_PKT_MAX];
1062 	int pack_done = 0;
1063 
1064 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1065 	if (datalen != 0)
1066 		return got_error(GOT_ERR_PRIVSEP_MSG);
1067 
1068 	packfd = imsg_get_fd(imsg);
1069 	if (packfd == -1)
1070 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
1071 
1072 	while (!pack_done) {
1073 		ssize_t r = 0;
1074 
1075 		err = got_poll_fd(infd, POLLIN, 1);
1076 		if (err) {
1077 			if (err->code != GOT_ERR_TIMEOUT)
1078 				break;
1079 			err = NULL;
1080 		} else {
1081 			r = read(infd, buf, sizeof(buf));
1082 			if (r == -1) {
1083 				err = got_error_from_errno("read");
1084 				break;
1085 			}
1086 			if (r == 0) {
1087 				/*
1088 				 * Git clients hang up their side of the
1089 				 * connection after sending the pack file.
1090 				 */
1091 				err = NULL;
1092 				pack_done = 1;
1093 				break;
1094 			}
1095 		}
1096 
1097 		if (r == 0) {
1098 			/* Detect gotd(8) closing the pack pipe when done. */
1099 			err = got_poll_fd(packfd, 0, 1);
1100 			if (err) {
1101 				if (err->code != GOT_ERR_TIMEOUT &&
1102 				    err->code != GOT_ERR_EOF)
1103 					break;
1104 				if (err->code == GOT_ERR_EOF)
1105 					pack_done = 1;
1106 				err = NULL;
1107 			}
1108 		} else {
1109 			/* Write pack data and/or detect pipe being closed. */
1110 			err = got_poll_write_full(packfd, buf, r);
1111 			if (err) {
1112 				if (err->code == GOT_ERR_EOF)
1113 					err = NULL;
1114 				break;
1115 			}
1116 		}
1117 	}
1118 
1119 	close(packfd);
1120 	return err;
1121 }
1122 
1123 static const struct got_error *
1124 report_unpack_status(struct imsg *imsg, int outfd, int chattygot)
1125 {
1126 	const struct got_error *err = NULL;
1127 	struct gotd_imsg_packfile_status istatus;
1128 	char buf[GOT_PKT_MAX];
1129 	size_t datalen, len;
1130 	char *reason = NULL;
1131 
1132 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1133 	if (datalen < sizeof(istatus))
1134 		return got_error(GOT_ERR_PRIVSEP_LEN);
1135 	memcpy(&istatus, imsg->data, sizeof(istatus));
1136 	if (datalen != sizeof(istatus) + istatus.reason_len)
1137 		return got_error(GOT_ERR_PRIVSEP_LEN);
1138 
1139 	reason = strndup(imsg->data + sizeof(istatus), istatus.reason_len);
1140 	if (reason == NULL) {
1141 		err = got_error_from_errno("strndup");
1142 		goto done;
1143 	}
1144 
1145 	if (err == NULL)
1146 		len = snprintf(buf, sizeof(buf), "unpack ok\n");
1147 	else
1148 		len = snprintf(buf, sizeof(buf), "unpack %s\n", reason);
1149 	if (len >= sizeof(buf)) {
1150 		err = got_error(GOT_ERR_NO_SPACE);
1151 		goto done;
1152 	}
1153 
1154 	err = got_pkt_writepkt(outfd, buf, len, chattygot);
1155 done:
1156 	free(reason);
1157 	return err;
1158 }
1159 
1160 static const struct got_error *
1161 recv_ref_update_ok(struct imsg *imsg, int outfd, int chattygot)
1162 {
1163 	const struct got_error *err = NULL;
1164 	struct gotd_imsg_ref_update_ok iok;
1165 	size_t datalen, len;
1166 	char buf[GOT_PKT_MAX];
1167 	char *refname = NULL;
1168 
1169 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1170 	if (datalen < sizeof(iok))
1171 		return got_error(GOT_ERR_PRIVSEP_LEN);
1172 	memcpy(&iok, imsg->data, sizeof(iok));
1173 	if (datalen != sizeof(iok) + iok.name_len)
1174 		return got_error(GOT_ERR_PRIVSEP_LEN);
1175 
1176 	memcpy(&iok, imsg->data, sizeof(iok));
1177 
1178 	refname = strndup(imsg->data + sizeof(iok), iok.name_len);
1179 	if (refname == NULL)
1180 		return got_error_from_errno("strndup");
1181 
1182 	len = snprintf(buf, sizeof(buf), "ok %s\n", refname);
1183 	if (len >= sizeof(buf)) {
1184 		err = got_error(GOT_ERR_NO_SPACE);
1185 		goto done;
1186 	}
1187 
1188 	err = got_pkt_writepkt(outfd, buf, len, chattygot);
1189 done:
1190 	free(refname);
1191 	return err;
1192 }
1193 
1194 static const struct got_error *
1195 recv_ref_update_ng(struct imsg *imsg, int outfd, int chattygot)
1196 {
1197 	const struct got_error *err = NULL;
1198 	struct gotd_imsg_ref_update_ng ing;
1199 	size_t datalen, len;
1200 	char buf[GOT_PKT_MAX];
1201 	char *refname = NULL, *reason = NULL;
1202 
1203 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1204 	if (datalen < sizeof(ing))
1205 		return got_error(GOT_ERR_PRIVSEP_LEN);
1206 	memcpy(&ing, imsg->data, sizeof(ing));
1207 	if (datalen != sizeof(ing) + ing.name_len + ing.reason_len)
1208 		return got_error(GOT_ERR_PRIVSEP_LEN);
1209 
1210 	memcpy(&ing, imsg->data, sizeof(ing));
1211 
1212 	refname = strndup(imsg->data + sizeof(ing), ing.name_len);
1213 	if (refname == NULL)
1214 		return got_error_from_errno("strndup");
1215 
1216 	reason = strndup(imsg->data + sizeof(ing) + ing.name_len,
1217 	    ing.reason_len);
1218 	if (reason == NULL) {
1219 		err = got_error_from_errno("strndup");
1220 		goto done;
1221 	}
1222 
1223 	len = snprintf(buf, sizeof(buf), "ng %s %s\n", refname, reason);
1224 	if (len >= sizeof(buf)) {
1225 		err = got_error(GOT_ERR_NO_SPACE);
1226 		goto done;
1227 	}
1228 
1229 	err = got_pkt_writepkt(outfd, buf, len, chattygot);
1230 done:
1231 	free(refname);
1232 	free(reason);
1233 	return err;
1234 }
1235 
1236 static const struct got_error *
1237 serve_write(int infd, int outfd, int gotd_sock, const char *repo_path,
1238     int chattygot)
1239 {
1240 	const struct got_error *err = NULL;
1241 	char buf[GOT_PKT_MAX];
1242 	struct imsgbuf ibuf;
1243 	enum protostate {
1244 		STATE_EXPECT_REF_UPDATE,
1245 		STATE_EXPECT_MORE_REF_UPDATES,
1246 		STATE_EXPECT_PACKFILE,
1247 		STATE_PACKFILE_RECEIVED,
1248 		STATE_REFS_UPDATED,
1249 	};
1250 	enum protostate curstate = STATE_EXPECT_REF_UPDATE;
1251 	struct imsg imsg;
1252 	int report_status = 0;
1253 
1254 	imsg_init(&ibuf, gotd_sock);
1255 	memset(&imsg, 0, sizeof(imsg));
1256 
1257 	err = announce_refs(outfd, &ibuf, 0, repo_path, chattygot);
1258 	if (err)
1259 		goto done;
1260 
1261 	while (curstate != STATE_EXPECT_PACKFILE) {
1262 		int n;
1263 		buf[0] = '\0';
1264 		err = got_pkt_readpkt(&n, infd, buf, sizeof(buf), chattygot);
1265 		if (err)
1266 			goto done;
1267 		if (n == 0) {
1268 			if (curstate == STATE_EXPECT_REF_UPDATE) {
1269 				/* The client will not send us anything. */
1270 				goto done;
1271 			} else if (curstate != STATE_EXPECT_MORE_REF_UPDATES) {
1272 				err = got_error_msg(GOT_ERR_BAD_PACKET,
1273 				    "unexpected flush packet received");
1274 				goto done;
1275 			}
1276 			err = forward_flushpkt(&ibuf);
1277 			if (err)
1278 				goto done;
1279 			curstate = STATE_EXPECT_PACKFILE;
1280 		} else if (n >= (SHA1_DIGEST_STRING_LENGTH * 2) + 2) {
1281 			if (curstate != STATE_EXPECT_REF_UPDATE &&
1282 			    curstate != STATE_EXPECT_MORE_REF_UPDATES) {
1283 				err = got_error_msg(GOT_ERR_BAD_PACKET,
1284 				    "unexpected ref-update packet");
1285 				goto done;
1286 			}
1287 			if (curstate == STATE_EXPECT_REF_UPDATE) {
1288 				err = recv_ref_update(&report_status,
1289 				    outfd, &ibuf, buf, n, 1, chattygot);
1290 			} else {
1291 				err = recv_ref_update(NULL, outfd, &ibuf,
1292 				    buf, n, 0, chattygot);
1293 			}
1294 			if (err)
1295 				goto done;
1296 			curstate = STATE_EXPECT_MORE_REF_UPDATES;
1297 		} else {
1298 			err = got_error(GOT_ERR_BAD_PACKET);
1299 			goto done;
1300 		}
1301 	}
1302 
1303 	while (curstate != STATE_PACKFILE_RECEIVED) {
1304 		err = gotd_imsg_poll_recv(&imsg, &ibuf, 0);
1305 		if (err)
1306 			goto done;
1307 		switch (imsg.hdr.type) {
1308 		case GOTD_IMSG_ERROR:
1309 			err = gotd_imsg_recv_error(NULL, &imsg);
1310 			goto done;
1311 		case GOTD_IMSG_PACKFILE_PIPE:
1312 			err = recv_packfile(&imsg, infd);
1313 			if (err) {
1314 				if (err->code != GOT_ERR_EOF)
1315 					goto done;
1316 				/*
1317 				 * EOF is reported when the client hangs up,
1318 				 * which can happen with Git clients.
1319 				 * The socket should stay half-open so we
1320 				 * can still send our reports if requested.
1321 				 */
1322 				err = NULL;
1323 			}
1324 			curstate = STATE_PACKFILE_RECEIVED;
1325 			break;
1326 		default:
1327 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1328 			break;
1329 		}
1330 
1331 		imsg_free(&imsg);
1332 		if (err)
1333 			goto done;
1334 	}
1335 
1336 	while (curstate != STATE_REFS_UPDATED && err == NULL) {
1337 		err = gotd_imsg_poll_recv(&imsg, &ibuf, 0);
1338 		if (err)
1339 			break;
1340 		switch (imsg.hdr.type) {
1341 		case GOTD_IMSG_ERROR:
1342 			err = gotd_imsg_recv_error(NULL, &imsg);
1343 			break;
1344 		case GOTD_IMSG_PACKFILE_STATUS:
1345 			if (!report_status)
1346 				break;
1347 			err = report_unpack_status(&imsg, outfd, chattygot);
1348 			break;
1349 		case GOTD_IMSG_REF_UPDATE_OK:
1350 			if (!report_status)
1351 				break;
1352 			err = recv_ref_update_ok(&imsg, outfd, chattygot);
1353 			break;
1354 		case GOTD_IMSG_REF_UPDATE_NG:
1355 			if (!report_status)
1356 				break;
1357 			err = recv_ref_update_ng(&imsg, outfd, chattygot);
1358 			break;
1359 		case GOTD_IMSG_REFS_UPDATED:
1360 			curstate = STATE_REFS_UPDATED;
1361 			err = got_pkt_flushpkt(outfd, chattygot);
1362 			break;
1363 		default:
1364 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1365 			break;
1366 		}
1367 
1368 		imsg_free(&imsg);
1369 	}
1370 done:
1371 	imsg_clear(&ibuf);
1372 	if (err)
1373 		echo_error(err, outfd, chattygot);
1374 	return err;
1375 }
1376 
1377 const struct got_error *
1378 got_serve(int infd, int outfd, const char *command, const char *repo_path,
1379     int gotd_sock, int chattygot)
1380 {
1381 	const struct got_error *err = NULL;
1382 
1383 	if (strcmp(command, GOT_DIAL_CMD_FETCH) == 0)
1384 		err = serve_read(infd, outfd, gotd_sock, repo_path, chattygot);
1385 	else if (strcmp(command, GOT_DIAL_CMD_SEND) == 0)
1386 		err = serve_write(infd, outfd, gotd_sock, repo_path,
1387 		    chattygot);
1388 	else
1389 		err = got_error(GOT_ERR_BAD_PACKET);
1390 
1391 	return err;
1392 }