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Date:: Wed Jan 18 17:53:30 2023 UTC
Message:: fix spurious "gotsh: unexpected flush packet" error when client is up-to-date ok op@
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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 <stdio.h>
27 #include <stdint.h>
28 #include <stdlib.h>
29 #include <string.h>
30 #include <imsg.h>
31 #include <unistd.h>
32 
33 #include "got_error.h"
34 #include "got_serve.h"
35 #include "got_path.h"
36 #include "got_version.h"
37 #include "got_reference.h"
38 
39 #include "got_lib_pkt.h"
40 #include "got_lib_dial.h"
41 #include "got_lib_gitproto.h"
42 #include "got_lib_sha1.h"
43 #include "got_lib_poll.h"
44 
45 #include "gotd.h"
46 
47 #ifndef nitems
48 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
49 #endif
50 
51 static const struct got_capability read_capabilities[] = {
52 	{ GOT_CAPA_AGENT, "got/" GOT_VERSION_STR },
53 	{ GOT_CAPA_OFS_DELTA, NULL },
54 	{ GOT_CAPA_SIDE_BAND_64K, NULL },
55 };
56 
57 static const struct got_capability write_capabilities[] = {
58 	{ GOT_CAPA_AGENT, "got/" GOT_VERSION_STR },
59 	{ GOT_CAPA_OFS_DELTA, NULL },
60 	{ GOT_CAPA_REPORT_STATUS, NULL },
61 	{ GOT_CAPA_NO_THIN, NULL },
62 #if 0
63 	{ GOT_CAPA_DELETE_REFS, NULL },
64 #endif
65 };
66 
67 static const struct got_error *
68 parse_command(char **command, char **repo_path, const char *gitcmd)
69 {
70 	const struct got_error *err = NULL;
71 	size_t len, cmdlen, pathlen;
72 	char *path0 = NULL, *path, *abspath = NULL, *canonpath = NULL;
73 	const char *relpath;
74 
75 	*command = NULL;
76 	*repo_path = NULL;
77 
78 	len = strlen(gitcmd);
79 
80 	if (len >= strlen(GOT_SERVE_CMD_SEND) &&
81 	    strncmp(gitcmd, GOT_SERVE_CMD_SEND,
82 	    strlen(GOT_SERVE_CMD_SEND)) == 0)
83 		cmdlen = strlen(GOT_SERVE_CMD_SEND);
84 	else if (len >= strlen(GOT_SERVE_CMD_FETCH) &&
85 	    strncmp(gitcmd, GOT_SERVE_CMD_FETCH,
86 	    strlen(GOT_SERVE_CMD_FETCH)) == 0)
87 		cmdlen = strlen(GOT_SERVE_CMD_FETCH);
88 	else
89 		return got_error(GOT_ERR_BAD_PACKET);
90 
91 	if (len <= cmdlen + 1 || gitcmd[cmdlen] != ' ')
92 		return got_error(GOT_ERR_BAD_PACKET);
93 
94 	if (memchr(&gitcmd[cmdlen + 1], '\0', len - cmdlen) == NULL)
95 		return got_error(GOT_ERR_BAD_PATH);
96 
97 	/* Forbid linefeeds in paths, like Git does. */
98 	if (memchr(&gitcmd[cmdlen + 1], '\n', len - cmdlen) != NULL)
99 		return got_error(GOT_ERR_BAD_PATH);
100 
101 	path0 = strdup(&gitcmd[cmdlen + 1]);
102 	if (path0 == NULL)
103 		return got_error_from_errno("strdup");
104 	path = path0;
105 	pathlen = strlen(path);
106 
107 	/*
108 	 * Git clients send a shell command.
109 	 * Trim spaces and quotes around the path.
110 	 */
111 	while (path[0] == '\'' || path[0] == '\"' || path[0] == ' ') {
112 		path++;
113 		pathlen--;
114 	}
115 	while (pathlen > 0 &&
116 	    (path[pathlen - 1] == '\'' || path[pathlen - 1] == '\"' ||
117 	    path[pathlen - 1] == ' ')) {
118 		path[pathlen - 1] = '\0';
119 		pathlen--;
120 	}
121 
122 	/* Deny an empty repository path. */
123 	if (path[0] == '\0' || got_path_is_root_dir(path)) {
124 		err = got_error(GOT_ERR_NOT_GIT_REPO);
125 		goto done;
126 	}
127 
128 	if (asprintf(&abspath, "/%s", path) == -1) {
129 		err = got_error_from_errno("asprintf");
130 		goto done;
131 	}
132 	pathlen = strlen(abspath);
133 	canonpath = malloc(pathlen);
134 	if (canonpath == NULL) {
135 		err = got_error_from_errno("malloc");
136 		goto done;
137 	}
138 	err = got_canonpath(abspath, canonpath, pathlen);
139 	if (err)
140 		goto done;
141 
142 	relpath = canonpath;
143 	while (relpath[0] == '/')
144 		relpath++;
145 	*repo_path = strdup(relpath);
146 	if (*repo_path == NULL) {
147 		err = got_error_from_errno("strdup");
148 		goto done;
149 	}
150 	*command = strndup(gitcmd, cmdlen);
151 	if (*command == NULL)
152 		err = got_error_from_errno("strndup");
153 done:
154 	free(path0);
155 	free(abspath);
156 	free(canonpath);
157 	if (err) {
158 		free(*repo_path);
159 		*repo_path = NULL;
160 	}
161 	return err;
162 }
163 
164 static const struct got_error *
165 append_read_capabilities(size_t *capalen, size_t len, const char *symrefstr,
166     uint8_t *buf, size_t bufsize)
167 {
168 	struct got_capability capa[nitems(read_capabilities) + 1];
169 	size_t ncapa;
170 
171 	memcpy(&capa, read_capabilities, sizeof(read_capabilities));
172 	if (symrefstr) {
173 		capa[nitems(read_capabilities)].key = "symref";
174 		capa[nitems(read_capabilities)].value = symrefstr;
175 		ncapa = nitems(capa);
176 	} else
177 		ncapa = nitems(read_capabilities);
178 
179 	return got_gitproto_append_capabilities(capalen, buf, len,
180 	    bufsize, capa, ncapa);
181 }
182 
183 static const struct got_error *
184 send_ref(int outfd, uint8_t *id, const char *refname, int send_capabilities,
185     int client_is_reading, const char *symrefstr, int chattygot)
186 {
187 	const struct got_error *err = NULL;
188 	char hex[SHA1_DIGEST_STRING_LENGTH];
189 	char buf[GOT_PKT_MAX];
190 	size_t len, capalen = 0;
191 
192 	if (got_sha1_digest_to_str(id, hex, sizeof(hex)) == NULL)
193 		return got_error(GOT_ERR_BAD_OBJ_ID);
194 
195 	len = snprintf(buf, sizeof(buf), "%s %s", hex, refname);
196 	if (len >= sizeof(buf))
197 		return got_error(GOT_ERR_NO_SPACE);
198 
199 	if (send_capabilities) {
200 		if (client_is_reading) {
201 			err = append_read_capabilities(&capalen, len,
202 			    symrefstr, buf, sizeof(buf));
203 		} else {
204 			err = got_gitproto_append_capabilities(&capalen,
205 			    buf, len, sizeof(buf), write_capabilities,
206 			    nitems(write_capabilities));
207 		}
208 		if (err)
209 			return err;
210 		len += capalen;
211 	}
212 
213 	if (len + 1 >= sizeof(buf))
214 		return got_error(GOT_ERR_NO_SPACE);
215 	buf[len] = '\n';
216 	len++;
217 	buf[len] = '\0';
218 
219 	return got_pkt_writepkt(outfd, buf, len, chattygot);
220 }
221 
222 static const struct got_error *
223 send_zero_refs(int outfd, int client_is_reading, int chattygot)
224 {
225 	const struct got_error *err = NULL;
226 	char buf[GOT_PKT_MAX];
227 	uint8_t zero[SHA1_DIGEST_LENGTH];
228 	char hex[SHA1_DIGEST_STRING_LENGTH];
229 	size_t len, capalen = 0;
230 
231 	memset(&zero, 0, sizeof(zero));
232 
233 	if (got_sha1_digest_to_str(zero, hex, sizeof(hex)) == NULL)
234 		return got_error(GOT_ERR_BAD_OBJ_ID);
235 
236 	len = snprintf(buf, sizeof(buf), "%s capabilities^{}", hex);
237 	if (len >= sizeof(buf))
238 		return got_error(GOT_ERR_NO_SPACE);
239 
240 	if (client_is_reading) {
241 		err = got_gitproto_append_capabilities(&capalen, buf, len,
242 		    sizeof(buf), read_capabilities, nitems(read_capabilities));
243 		if (err)
244 			return err;
245 	} else {
246 		err = got_gitproto_append_capabilities(&capalen, buf, len,
247 		    sizeof(buf), write_capabilities,
248 		    nitems(write_capabilities));
249 		if (err)
250 			return err;
251 	}
252 
253 	return got_pkt_writepkt(outfd, buf, len + capalen, chattygot);
254 }
255 
256 static void
257 echo_error(const struct got_error *err, int outfd, int chattygot)
258 {
259 	char buf[4 + GOT_ERR_MAX_MSG_SIZE];
260 	size_t len;
261 
262 	/*
263 	 * Echo the error to the client on a pkt-line.
264 	 * The client should then terminate its session.
265 	 */
266 	buf[0] = 'E'; buf[1] = 'R'; buf[2] = 'R'; buf[3] = ' '; buf[4] = '\0';
267 	len = strlcat(buf, err->msg, sizeof(buf));
268 	got_pkt_writepkt(outfd, buf, len, chattygot);
269 }
270 
271 static const struct got_error *
272 announce_refs(int outfd, struct imsgbuf *ibuf, int client_is_reading,
273     const char *repo_path, int chattygot)
274 {
275 	const struct got_error *err = NULL;
276 	struct imsg imsg;
277 	size_t datalen;
278 	struct gotd_imsg_list_refs lsref;
279 	struct gotd_imsg_reflist ireflist;
280 	struct gotd_imsg_ref iref;
281 	struct gotd_imsg_symref isymref;
282 	size_t nrefs = 0;
283 	int have_nrefs = 0, sent_capabilities = 0;
284 	char *symrefname = NULL, *symreftarget = NULL, *symrefstr = NULL;
285 	char *refname = NULL;
286 
287 	memset(&imsg, 0, sizeof(imsg));
288 	memset(&lsref, 0, sizeof(lsref));
289 
290 	if (strlcpy(lsref.repo_name, repo_path, sizeof(lsref.repo_name)) >=
291 	    sizeof(lsref.repo_name))
292 		return got_error(GOT_ERR_NO_SPACE);
293 	lsref.client_is_reading = client_is_reading;
294 	
295 	if (imsg_compose(ibuf, GOTD_IMSG_LIST_REFS, 0, 0, -1,
296 	    &lsref, sizeof(lsref)) == -1)
297 		return got_error_from_errno("imsg_compose LIST_REFS");
298 
299 	err = gotd_imsg_flush(ibuf);
300 	if (err)
301 		return err;
302 
303 	while (!have_nrefs || nrefs > 0) {
304 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
305 		if (err)
306 			goto done;
307 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
308 		switch (imsg.hdr.type) {
309 		case GOTD_IMSG_ERROR:
310 			err = gotd_imsg_recv_error(NULL, &imsg);
311 			goto done;
312 		case GOTD_IMSG_REFLIST:
313 			if (have_nrefs || nrefs > 0) {
314 				err = got_error(GOT_ERR_PRIVSEP_MSG);
315 				goto done;
316 			}
317 			if (datalen != sizeof(ireflist)) {
318 				err = got_error(GOT_ERR_PRIVSEP_MSG);
319 				goto done;
320 			}
321 			memcpy(&ireflist, imsg.data, sizeof(ireflist));
322 			nrefs = ireflist.nrefs;
323 			have_nrefs = 1;
324 			if (nrefs == 0)
325 				err = send_zero_refs(outfd, client_is_reading,
326 				    chattygot);
327 			break;
328 		case GOTD_IMSG_REF:
329 			if (!have_nrefs || nrefs == 0) {
330 				err = got_error(GOT_ERR_PRIVSEP_MSG);
331 				goto done;
332 			}
333 			if (datalen < sizeof(iref)) {
334 				err = got_error(GOT_ERR_PRIVSEP_MSG);
335 				goto done;
336 			}
337 			memcpy(&iref, imsg.data, sizeof(iref));
338 			if (datalen != sizeof(iref) + iref.name_len) {
339 				err = got_error(GOT_ERR_PRIVSEP_LEN);
340 				goto done;
341 			}
342 			refname = strndup(imsg.data + sizeof(iref),
343 			    iref.name_len);
344 			if (refname == NULL) {
345 				err = got_error_from_errno("strndup");
346 				goto done;
347 			}
348 			err = send_ref(outfd, iref.id, refname,
349 			    !sent_capabilities, client_is_reading,
350 			    NULL, chattygot);
351 			free(refname);
352 			refname = NULL;
353 			if (err)
354 				goto done;
355 			sent_capabilities = 1;
356 			if (nrefs > 0)
357 				nrefs--;
358 			break;
359 		case GOTD_IMSG_SYMREF:
360 			if (!have_nrefs || nrefs == 0) {
361 				err = got_error(GOT_ERR_PRIVSEP_MSG);
362 				goto done;
363 			}
364 			if (datalen < sizeof(isymref)) {
365 				err = got_error(GOT_ERR_PRIVSEP_LEN);
366 				goto done;
367 			}
368 			memcpy(&isymref, imsg.data, sizeof(isymref));
369 			if (datalen != sizeof(isymref) + isymref.name_len +
370 			    isymref.target_len) {
371 				err = got_error(GOT_ERR_PRIVSEP_LEN);
372 				goto done;
373 			}
374 
375 			/*
376 			 * For now, we only announce one symbolic ref,
377 			 * as part of our capability advertisement.
378 			 */
379 			if (sent_capabilities || symrefstr != NULL ||
380 			    symrefname != NULL || symreftarget != NULL)
381 				break;
382 
383 			symrefname = strndup(imsg.data + sizeof(isymref),
384 			    isymref.name_len);
385 			if (symrefname == NULL) {
386 				err = got_error_from_errno("malloc");
387 				goto done;
388 			}
389 
390 			symreftarget = strndup(
391 			    imsg.data + sizeof(isymref) + isymref.name_len,
392 			    isymref.target_len);
393 			if (symreftarget == NULL) {
394 				err = got_error_from_errno("strndup");
395 				goto done;
396 			}
397 
398 			if (asprintf(&symrefstr, "%s:%s", symrefname,
399 			    symreftarget) == -1) {
400 				err = got_error_from_errno("asprintf");
401 				goto done;
402 			}
403 			err = send_ref(outfd, isymref.target_id, symrefname,
404 			    !sent_capabilities, client_is_reading, symrefstr,
405 			    chattygot);
406 			free(refname);
407 			refname = NULL;
408 			if (err)
409 				goto done;
410 			sent_capabilities = 1;
411 			if (nrefs > 0)
412 				nrefs--;
413 			break;
414 		default:
415 			err = got_error(GOT_ERR_PRIVSEP_MSG);
416 			break;
417 		}
418 
419 		imsg_free(&imsg);
420 	}
421 
422 	err = got_pkt_flushpkt(outfd, chattygot);
423 	if (err)
424 		goto done;
425 done:
426 	free(symrefstr);
427 	free(symrefname);
428 	free(symreftarget);
429 	return err;
430 }
431 
432 static const struct got_error *
433 parse_want_line(char **common_capabilities, uint8_t *id, char *buf, size_t len)
434 {
435 	const struct got_error *err;
436 	char *id_str = NULL, *client_capabilities = NULL;
437 
438 	err = got_gitproto_parse_want_line(&id_str,
439 	    &client_capabilities, buf, len);
440 	if (err)
441 		return err;
442 
443 	if (!got_parse_sha1_digest(id, id_str)) {
444 		err = got_error_msg(GOT_ERR_BAD_PACKET,
445 		    "want-line with bad object ID");
446 		goto done;
447 	}
448 
449 	if (client_capabilities) {
450 		err = got_gitproto_match_capabilities(common_capabilities,
451 		    NULL, client_capabilities, read_capabilities,
452 		    nitems(read_capabilities));
453 		if (err)
454 			goto done;
455 	}
456 done:
457 	free(id_str);
458 	free(client_capabilities);
459 	return err;
460 }
461 
462 static const struct got_error *
463 parse_have_line(uint8_t *id, char *buf, size_t len)
464 {
465 	const struct got_error *err;
466 	char *id_str = NULL;
467 
468 	err = got_gitproto_parse_have_line(&id_str, buf, len);
469 	if (err)
470 		return err;
471 
472 	if (!got_parse_sha1_digest(id, id_str)) {
473 		err = got_error_msg(GOT_ERR_BAD_PACKET,
474 		    "have-line with bad object ID");
475 		goto done;
476 	}
477 done:
478 	free(id_str);
479 	return err;
480 }
481 
482 static const struct got_error *
483 send_capability(struct got_capability *capa, struct imsgbuf *ibuf)
484 {
485 	const struct got_error *err = NULL;
486 	struct gotd_imsg_capability icapa;
487 	size_t len;
488 	struct ibuf *wbuf;
489 
490 	memset(&icapa, 0, sizeof(icapa));
491 
492 	icapa.key_len = strlen(capa->key);
493 	len = sizeof(icapa) + icapa.key_len;
494 	if (capa->value) {
495 		icapa.value_len = strlen(capa->value);
496 		len += icapa.value_len;
497 	}
498 
499 	wbuf = imsg_create(ibuf, GOTD_IMSG_CAPABILITY, 0, 0, len);
500 	if (wbuf == NULL) {
501 		err = got_error_from_errno("imsg_create CAPABILITY");
502 		return err;
503 	}
504 
505 	if (imsg_add(wbuf, &icapa, sizeof(icapa)) == -1)
506 		return got_error_from_errno("imsg_add CAPABILITY");
507 	if (imsg_add(wbuf, capa->key, icapa.key_len) == -1)
508 		return got_error_from_errno("imsg_add CAPABILITY");
509 	if (capa->value) {
510 		if (imsg_add(wbuf, capa->value, icapa.value_len) == -1)
511 			return got_error_from_errno("imsg_add CAPABILITY");
512 	}
513 
514 	wbuf->fd = -1;
515 	imsg_close(ibuf, wbuf);
516 
517 	return NULL;
518 }
519 
520 static const struct got_error *
521 send_capabilities(int *use_sidebands, int *report_status,
522     char *capabilities_str, struct imsgbuf *ibuf)
523 {
524 	const struct got_error *err = NULL;
525 	struct gotd_imsg_capabilities icapas;
526 	struct got_capability *capa = NULL;
527 	size_t ncapa, i;
528 
529 	err = got_gitproto_split_capabilities_str(&capa, &ncapa,
530 	    capabilities_str);
531 	if (err)
532 		return err;
533 
534 	icapas.ncapabilities = ncapa;
535 	if (imsg_compose(ibuf, GOTD_IMSG_CAPABILITIES, 0, 0, -1,
536 	    &icapas, sizeof(icapas)) == -1) {
537 		err = got_error_from_errno("imsg_compose IMSG_CAPABILITIES");
538 		goto done;
539 	}
540 
541 	for (i = 0; i < ncapa; i++) {
542 		err = send_capability(&capa[i], ibuf);
543 		if (err)
544 			goto done;
545 		if (use_sidebands &&
546 		    strcmp(capa[i].key, GOT_CAPA_SIDE_BAND_64K) == 0)
547 			*use_sidebands = 1;
548 		if (report_status &&
549 		    strcmp(capa[i].key, GOT_CAPA_REPORT_STATUS) == 0)
550 			*report_status = 1;
551 	}
552 done:
553 	free(capa);
554 	return err;
555 }
556 
557 static const struct got_error *
558 forward_flushpkt(struct imsgbuf *ibuf)
559 {
560 	if (imsg_compose(ibuf, GOTD_IMSG_FLUSH, 0, 0, -1, NULL, 0) == -1)
561 		return got_error_from_errno("imsg_compose FLUSH");
562 
563 	return gotd_imsg_flush(ibuf);
564 }
565 
566 static const struct got_error *
567 recv_ack(struct imsg *imsg, uint8_t *expected_id)
568 {
569 	struct gotd_imsg_ack iack;
570 	size_t datalen;
571 
572 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
573 	if (datalen != sizeof(iack))
574 		return got_error(GOT_ERR_PRIVSEP_LEN);
575 
576 	memcpy(&iack, imsg->data, sizeof(iack));
577 	if (memcmp(iack.object_id, expected_id, SHA1_DIGEST_LENGTH) != 0)
578 		return got_error(GOT_ERR_BAD_OBJ_ID);
579 
580 	return NULL;
581 }
582 
583 static const struct got_error *
584 recv_nak(struct imsg *imsg, uint8_t *expected_id)
585 {
586 	struct gotd_imsg_ack inak;
587 	size_t datalen;
588 
589 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
590 	if (datalen != sizeof(inak))
591 		return got_error(GOT_ERR_PRIVSEP_LEN);
592 
593 	memcpy(&inak, imsg->data, sizeof(inak));
594 	if (memcmp(inak.object_id, expected_id, SHA1_DIGEST_LENGTH) != 0)
595 		return got_error(GOT_ERR_BAD_OBJ_ID);
596 
597 	return NULL;
598 }
599 
600 
601 static const struct got_error *
602 recv_want(int *use_sidebands, int outfd, struct imsgbuf *ibuf,
603     char *buf, size_t len, int expect_capabilities, int chattygot)
604 {
605 	const struct got_error *err;
606 	struct gotd_imsg_want iwant;
607 	char *capabilities_str;
608 	int done = 0;
609 	struct imsg imsg;
610 
611 	memset(&iwant, 0, sizeof(iwant));
612 	memset(&imsg, 0, sizeof(imsg));
613 
614 	err = parse_want_line(&capabilities_str, iwant.object_id, buf, len);
615 	if (err)
616 		return err;
617 
618 	if (capabilities_str) {
619 		if (!expect_capabilities) {
620 			err = got_error_msg(GOT_ERR_BAD_PACKET,
621 			    "unexpected capability announcement received");
622 			goto done;
623 		}
624 		err = send_capabilities(use_sidebands, NULL, capabilities_str,
625 		    ibuf);
626 		if (err)
627 			goto done;
628 
629 	}
630 
631 	if (imsg_compose(ibuf, GOTD_IMSG_WANT, 0, 0, -1,
632 	    &iwant, sizeof(iwant)) == -1) {
633 		err = got_error_from_errno("imsg_compose WANT");
634 		goto done;
635 	}
636 
637 	err = gotd_imsg_flush(ibuf);
638 	if (err)
639 		goto done;
640 
641 	/*
642 	 * Wait for an ACK, or an error in case the desired object
643 	 * does not exist.
644 	 */
645 	while (!done && err == NULL) {
646 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
647 		if (err)
648 			break;
649 		switch (imsg.hdr.type) {
650 		case GOTD_IMSG_ERROR:
651 			err = gotd_imsg_recv_error(NULL, &imsg);
652 			break;
653 		case GOTD_IMSG_ACK:
654 			err = recv_ack(&imsg, iwant.object_id);
655 			if (err)
656 				break;
657 			done = 1;
658 			break;
659 		default:
660 			err = got_error(GOT_ERR_PRIVSEP_MSG);
661 			break;
662 		}
663 
664 		imsg_free(&imsg);
665 	}
666 done:
667 	free(capabilities_str);
668 	return err;
669 }
670 
671 static const struct got_error *
672 send_ack(int outfd, uint8_t *id, int chattygot)
673 {
674 	char hex[SHA1_DIGEST_STRING_LENGTH];
675 	char buf[GOT_PKT_MAX];
676 	int len;
677 
678 	if (got_sha1_digest_to_str(id, hex, sizeof(hex)) == NULL)
679 		return got_error(GOT_ERR_BAD_OBJ_ID);
680 
681 	len = snprintf(buf, sizeof(buf), "ACK %s\n", hex);
682 	if (len >= sizeof(buf))
683 		return got_error(GOT_ERR_NO_SPACE);
684 
685 	return got_pkt_writepkt(outfd, buf, len, chattygot);
686 }
687 
688 static const struct got_error *
689 send_nak(int outfd, int chattygot)
690 {
691 	char buf[5];
692 	int len;
693 
694 	len = snprintf(buf, sizeof(buf), "NAK\n");
695 	if (len >= sizeof(buf))
696 		return got_error(GOT_ERR_NO_SPACE);
697 
698 	return got_pkt_writepkt(outfd, buf, len, chattygot);
699 }
700 
701 static const struct got_error *
702 recv_have(int *have_ack, int outfd, struct imsgbuf *ibuf, char *buf,
703     size_t len, int chattygot)
704 {
705 	const struct got_error *err;
706 	struct gotd_imsg_have ihave;
707 	int done = 0;
708 	struct imsg imsg;
709 
710 	memset(&ihave, 0, sizeof(ihave));
711 	memset(&imsg, 0, sizeof(imsg));
712 
713 	err = parse_have_line(ihave.object_id, buf, len);
714 	if (err)
715 		return err;
716 
717 	if (imsg_compose(ibuf, GOTD_IMSG_HAVE, 0, 0, -1,
718 	    &ihave, sizeof(ihave)) == -1)
719 		return got_error_from_errno("imsg_compose HAVE");
720 
721 	err = gotd_imsg_flush(ibuf);
722 	if (err)
723 		return err;
724 
725 	/*
726 	 * Wait for an ACK or a NAK, indicating whether a common
727 	 * commit object has been found.
728 	 */
729 	while (!done && err == NULL) {
730 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
731 		if (err)
732 			return err;
733 		switch (imsg.hdr.type) {
734 		case GOTD_IMSG_ERROR:
735 			err = gotd_imsg_recv_error(NULL, &imsg);
736 			break;
737 		case GOTD_IMSG_ACK:
738 			err = recv_ack(&imsg, ihave.object_id);
739 			if (err)
740 				break;
741 			if (!*have_ack) {
742 				err = send_ack(outfd, ihave.object_id,
743 				    chattygot);
744 				if (err)
745 					return err;
746 				*have_ack = 1;
747 			}
748 			done = 1;
749 			break;
750 		case GOTD_IMSG_NAK:
751 			err = recv_nak(&imsg, ihave.object_id);
752 			if (err)
753 				break;
754 			done = 1;
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 recv_done(int *packfd, int outfd, struct imsgbuf *ibuf, int chattygot)
769 {
770 	const struct got_error *err;
771 	struct imsg imsg;
772 
773 	*packfd = -1;
774 
775 	if (imsg_compose(ibuf, GOTD_IMSG_DONE, 0, 0, -1, NULL, 0) == -1)
776 		return got_error_from_errno("imsg_compose DONE");
777 
778 	err = gotd_imsg_flush(ibuf);
779 	if (err)
780 		return err;
781 
782 	while (*packfd == -1 && err == NULL) {
783 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
784 		if (err)
785 			break;
786 
787 		switch (imsg.hdr.type) {
788 		case GOTD_IMSG_ERROR:
789 			err = gotd_imsg_recv_error(NULL, &imsg);
790 			break;
791 		case GOTD_IMSG_PACKFILE_PIPE:
792 			if (imsg.fd != -1)
793 				*packfd = imsg.fd;
794 			else
795 				err = got_error(GOT_ERR_PRIVSEP_NO_FD);
796 			break;
797 		default:
798 			err = got_error(GOT_ERR_PRIVSEP_MSG);
799 			break;
800 		}
801 
802 		imsg_free(&imsg);
803 	}
804 
805 	return err;
806 }
807 
808 static const struct got_error *
809 relay_progress_reports(struct imsgbuf *ibuf, int outfd, int chattygot)
810 {
811 	const struct got_error *err = NULL;
812 	int pack_starting = 0;
813 	struct gotd_imsg_packfile_progress iprog;
814 	char buf[GOT_PKT_MAX];
815 	struct imsg imsg;
816 	size_t datalen;
817 	int p_deltify = 0, n;
818 	const char *eol = "\r";
819 
820 	memset(&imsg, 0, sizeof(imsg));
821 
822 	while (!pack_starting && err == NULL) {
823 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
824 		if (err)
825 			break;
826 
827 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
828 		switch (imsg.hdr.type) {
829 		case GOTD_IMSG_ERROR:
830 			err = gotd_imsg_recv_error(NULL, &imsg);
831 			break;
832 		case GOTD_IMSG_PACKFILE_READY:
833 			eol = "\n";
834 			pack_starting = 1;
835 			/* fallthrough */
836 		case GOTD_IMSG_PACKFILE_PROGRESS:
837 			if (datalen != sizeof(iprog)) {
838 				err = got_error(GOT_ERR_PRIVSEP_LEN);
839 				break;
840 			}
841 			memcpy(&iprog, imsg.data, sizeof(iprog));
842 			if (iprog.nobj_total > 0) {
843 				p_deltify = (iprog.nobj_deltify * 100) /
844 				    iprog.nobj_total;
845 			}
846 			buf[0] = GOT_SIDEBAND_PROGRESS_INFO;
847 			n = snprintf(&buf[1], sizeof(buf) - 1,
848 			    "%d commits colored, "
849 			    "%d objects found, "
850 			    "deltify %d%%%s",
851 			    iprog.ncolored,
852 			    iprog.nfound,
853 			    p_deltify, eol);
854 			if (n >= sizeof(buf) - 1)
855 				break;
856 			err = got_pkt_writepkt(outfd, buf, 1 + n, chattygot);
857 			break;
858 		default:
859 			err = got_error(GOT_ERR_PRIVSEP_MSG);
860 			break;
861 		}
862 
863 		imsg_free(&imsg);
864 	}
865 
866 	return err;
867 }
868 
869 static const struct got_error *
870 serve_read(int infd, int outfd, int gotd_sock, const char *repo_path,
871     int chattygot)
872 {
873 	const struct got_error *err = NULL;
874 	char buf[GOT_PKT_MAX];
875 	struct imsgbuf ibuf;
876 	enum protostate {
877 		STATE_EXPECT_WANT,
878 		STATE_EXPECT_MORE_WANT,
879 		STATE_EXPECT_HAVE,
880 		STATE_EXPECT_DONE,
881 		STATE_DONE,
882 	};
883 	enum protostate curstate = STATE_EXPECT_WANT;
884 	int have_ack = 0, use_sidebands = 0, seen_have = 0;
885 	int packfd = -1;
886 	size_t pack_chunksize;
887 
888 	imsg_init(&ibuf, gotd_sock);
889 
890 	err = announce_refs(outfd, &ibuf, 1, repo_path, chattygot);
891 	if (err)
892 		goto done;
893 
894 	while (curstate != STATE_DONE) {
895 		int n;
896 		buf[0] = '\0';
897 		err = got_pkt_readpkt(&n, infd, buf, sizeof(buf), chattygot);
898 		if (err)
899 			break;
900 		if (n == 0) {
901 			if (curstate != STATE_EXPECT_WANT &&
902 			    curstate != STATE_EXPECT_MORE_WANT &&
903 			    curstate != STATE_EXPECT_HAVE &&
904 			    curstate != STATE_EXPECT_DONE) {
905 				err = got_error_msg(GOT_ERR_BAD_PACKET,
906 				    "unexpected flush packet received");
907 				goto done;
908 			}
909 
910 			if (curstate == STATE_EXPECT_WANT) {
911 				ssize_t r;
912 				/*
913 				 * If the client does not want to fetch
914 				 * anything we should receive a flush
915 				 * packet followed by EOF.
916 				 */
917 				r = read(infd, buf, sizeof(buf));
918 				if (r == -1) {
919 					err = got_error_from_errno("read");
920 					goto done;
921 				}
922 				if (r == 0) /* EOF */
923 					goto done;
924 
925 				/* Zero-length field followed by payload. */
926 				err = got_error_msg(GOT_ERR_BAD_PACKET,
927 				    "unexpected flush packet received");
928 				goto done;
929 			}
930 
931 			err = forward_flushpkt(&ibuf);
932 			if (err)
933 				goto done;
934 			if (curstate == STATE_EXPECT_HAVE && !have_ack) {
935 				err = send_nak(outfd, chattygot);
936 				if (err)
937 					goto done;
938 			}
939 			if (curstate == STATE_EXPECT_MORE_WANT)
940 				curstate = STATE_EXPECT_HAVE;
941 			else
942 				curstate = STATE_EXPECT_DONE;
943 		} else if (n >= 5 && strncmp(buf, "want ", 5) == 0) {
944 			if (curstate != STATE_EXPECT_WANT &&
945 			    curstate != STATE_EXPECT_MORE_WANT) {
946 				err = got_error_msg(GOT_ERR_BAD_PACKET,
947 				    "unexpected 'want' packet");
948 				goto done;
949 			}
950 			err = recv_want(&use_sidebands, outfd, &ibuf, buf, n,
951 			    curstate == STATE_EXPECT_WANT ? 1 : 0, chattygot);
952 			if (err)
953 				goto done;
954 			if (curstate == STATE_EXPECT_WANT)
955 				curstate = STATE_EXPECT_MORE_WANT;
956 		} else if (n >= 5 && strncmp(buf, "have ", 5) == 0) {
957 			if (curstate != STATE_EXPECT_HAVE &&
958 			    curstate != STATE_EXPECT_DONE) {
959 				err = got_error_msg(GOT_ERR_BAD_PACKET,
960 				    "unexpected 'have' packet");
961 				goto done;
962 			}
963 			if (curstate == STATE_EXPECT_HAVE) {
964 				err = recv_have(&have_ack, outfd, &ibuf,
965 				    buf, n, chattygot);
966 				if (err)
967 					goto done;
968 				seen_have = 1;
969 				if (have_ack)
970 					curstate = STATE_EXPECT_DONE;
971 			}
972 		} else if (n == 5 && strncmp(buf, "done\n", 5) == 0) {
973 			if (curstate != STATE_EXPECT_HAVE &&
974 			    curstate != STATE_EXPECT_DONE) {
975 				err = got_error_msg(GOT_ERR_BAD_PACKET,
976 				    "unexpected 'done' packet");
977 				goto done;
978 			}
979 			err = recv_done(&packfd, outfd, &ibuf, chattygot);
980 			if (err)
981 				goto done;
982 			curstate = STATE_DONE;
983 			break;
984 		} else {
985 			err = got_error(GOT_ERR_BAD_PACKET);
986 			goto done;
987 		}
988 	}
989 
990 	if (!seen_have) {
991 		err = send_nak(outfd, chattygot);
992 		if (err)
993 			goto done;
994 	}
995 
996 	if (use_sidebands) {
997 		err = relay_progress_reports(&ibuf, outfd, chattygot);
998 		if (err)
999 			goto done;
1000 		pack_chunksize = GOT_SIDEBAND_64K_PACKFILE_DATA_MAX;
1001 	} else
1002 		pack_chunksize = sizeof(buf);
1003 
1004 	for (;;) {
1005 		ssize_t r;
1006 
1007 		r = read(packfd, use_sidebands ? &buf[1] : buf,
1008 		    pack_chunksize);
1009 		if (r == -1) {
1010 			err = got_error_from_errno("read");
1011 			break;
1012 		} else if (r == 0) {
1013 			err = got_pkt_flushpkt(outfd, chattygot);
1014 			break;
1015 		}
1016 
1017 		if (use_sidebands) {
1018 			buf[0] = GOT_SIDEBAND_PACKFILE_DATA;
1019 			err = got_pkt_writepkt(outfd, buf, 1 + r, chattygot);
1020 			if (err)
1021 				break;
1022 		} else {
1023 			err = got_poll_write_full(outfd, buf, r);
1024 			if (err) {
1025 				if (err->code == GOT_ERR_EOF)
1026 					err = NULL;
1027 				break;
1028 			}
1029 		}
1030 	}
1031 done:
1032 	imsg_clear(&ibuf);
1033 	if (packfd != -1 && close(packfd) == -1 && err == NULL)
1034 		err = got_error_from_errno("close");
1035 	if (err)
1036 		echo_error(err, outfd, chattygot);
1037 	return err;
1038 }
1039 
1040 static const struct got_error *
1041 parse_ref_update_line(char **common_capabilities, char **refname,
1042     uint8_t *old_id, uint8_t *new_id, char *buf, size_t len)
1043 {
1044 	const struct got_error *err;
1045 	char *old_id_str = NULL, *new_id_str = NULL;
1046 	char *client_capabilities = NULL;
1047 
1048 	*refname = NULL;
1049 
1050 	err = got_gitproto_parse_ref_update_line(&old_id_str, &new_id_str,
1051 	    refname, &client_capabilities, buf, len);
1052 	if (err)
1053 		return err;
1054 
1055 	if (!got_parse_sha1_digest(old_id, old_id_str) ||
1056 	    !got_parse_sha1_digest(new_id, new_id_str)) {
1057 		err = got_error_msg(GOT_ERR_BAD_PACKET,
1058 		    "ref-update with bad object ID");
1059 		goto done;
1060 	}
1061 	if (!got_ref_name_is_valid(*refname)) {
1062 		err = got_error_msg(GOT_ERR_BAD_PACKET,
1063 		    "ref-update with bad reference name");
1064 		goto done;
1065 	}
1066 
1067 	if (client_capabilities) {
1068 		err = got_gitproto_match_capabilities(common_capabilities,
1069 		    NULL, client_capabilities, write_capabilities,
1070 		    nitems(write_capabilities));
1071 		if (err)
1072 			goto done;
1073 	}
1074 done:
1075 	free(old_id_str);
1076 	free(new_id_str);
1077 	free(client_capabilities);
1078 	if (err) {
1079 		free(*refname);
1080 		*refname = NULL;
1081 	}
1082 	return err;
1083 }
1084 
1085 static const struct got_error *
1086 recv_ref_update(int *report_status, int outfd, struct imsgbuf *ibuf,
1087     char *buf, size_t len, int expect_capabilities, int chattygot)
1088 {
1089 	const struct got_error *err;
1090 	struct gotd_imsg_ref_update iref;
1091 	struct ibuf *wbuf;
1092 	char *capabilities_str = NULL, *refname = NULL;
1093 	int done = 0;
1094 	struct imsg imsg;
1095 
1096 	memset(&iref, 0, sizeof(iref));
1097 	memset(&imsg, 0, sizeof(imsg));
1098 
1099 	err = parse_ref_update_line(&capabilities_str, &refname,
1100 	    iref.old_id, iref.new_id, buf, len);
1101 	if (err)
1102 		return err;
1103 
1104 	if (capabilities_str) {
1105 		if (!expect_capabilities) {
1106 			err = got_error_msg(GOT_ERR_BAD_PACKET,
1107 			    "unexpected capability announcement received");
1108 			goto done;
1109 		}
1110 		err = send_capabilities(NULL, report_status, capabilities_str,
1111 		    ibuf);
1112 		if (err)
1113 			goto done;
1114 	}
1115 
1116 	iref.name_len = strlen(refname);
1117 	len = sizeof(iref) + iref.name_len;
1118 	wbuf = imsg_create(ibuf, GOTD_IMSG_REF_UPDATE, 0, 0, len);
1119 	if (wbuf == NULL) {
1120 		err = got_error_from_errno("imsg_create REF_UPDATE");
1121 		goto done;
1122 	}
1123 
1124 	if (imsg_add(wbuf, &iref, sizeof(iref)) == -1)
1125 		return got_error_from_errno("imsg_add REF_UPDATE");
1126 	if (imsg_add(wbuf, refname, iref.name_len) == -1)
1127 		return got_error_from_errno("imsg_add REF_UPDATE");
1128 	wbuf->fd = -1;
1129 	imsg_close(ibuf, wbuf);
1130 
1131 	err = gotd_imsg_flush(ibuf);
1132 	if (err)
1133 		goto done;
1134 
1135 	/* Wait for ACK or an error. */
1136 	while (!done && err == NULL) {
1137 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
1138 		if (err)
1139 			break;
1140 		switch (imsg.hdr.type) {
1141 		case GOTD_IMSG_ERROR:
1142 			err = gotd_imsg_recv_error(NULL, &imsg);
1143 			break;
1144 		case GOTD_IMSG_ACK:
1145 			err = recv_ack(&imsg, iref.new_id);
1146 			if (err)
1147 				break;
1148 			done = 1;
1149 			break;
1150 		default:
1151 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1152 			break;
1153 		}
1154 
1155 		imsg_free(&imsg);
1156 	}
1157 done:
1158 	free(capabilities_str);
1159 	free(refname);
1160 	return err;
1161 }
1162 
1163 static const struct got_error *
1164 recv_packfile(struct imsg *imsg, int infd)
1165 {
1166 	const struct got_error *err = NULL;
1167 	size_t datalen;
1168 	int packfd;
1169 	char buf[GOT_PKT_MAX];
1170 	int pack_done = 0;
1171 
1172 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1173 	if (datalen != 0)
1174 		return got_error(GOT_ERR_PRIVSEP_MSG);
1175 
1176 	if (imsg->fd == -1)
1177 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
1178 	
1179 	packfd = imsg->fd;
1180 	while (!pack_done) {
1181 		ssize_t r = 0;
1182 
1183 		err = got_poll_fd(infd, POLLIN, 1);
1184 		if (err) {
1185 			if (err->code != GOT_ERR_TIMEOUT)
1186 				break;
1187 			err = NULL;
1188 		} else {
1189 			r = read(infd, buf, sizeof(buf));
1190 			if (r == -1) {
1191 				err = got_error_from_errno("read");
1192 				break;
1193 			}
1194 			if (r == 0) {
1195 				/*
1196 				 * Git clients hang up their side of the
1197 				 * connection after sending the pack file.
1198 				 */
1199 				err = NULL;
1200 				pack_done = 1;
1201 				break;
1202 			}
1203 		}
1204 
1205 		if (r == 0) {
1206 			/* Detect gotd(8) closing the pack pipe when done. */
1207 			err = got_poll_fd(packfd, POLLOUT, 1);
1208 			if (err) {
1209 				if (err->code != GOT_ERR_EOF)
1210 					break;
1211 				err = NULL;
1212 				pack_done = 1;
1213 			}
1214 		} else {
1215 			/* Write pack data and/or detect pipe being closed. */
1216 			err = got_poll_write_full(packfd, buf, r);
1217 			if (err) {
1218 				if (err->code == GOT_ERR_EOF)
1219 					err = NULL;
1220 				break;
1221 			}
1222 		}
1223 	}
1224 
1225 	close(packfd);
1226 	return err;
1227 }
1228 
1229 static const struct got_error *
1230 report_unpack_status(struct imsg *imsg, int outfd, int chattygot)
1231 {
1232 	const struct got_error *err = NULL;
1233 	struct gotd_imsg_packfile_status istatus;
1234 	char buf[GOT_PKT_MAX];
1235 	size_t datalen, len;
1236 	char *reason = NULL;
1237 
1238 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1239 	if (datalen < sizeof(istatus))
1240 		return got_error(GOT_ERR_PRIVSEP_LEN);
1241 	memcpy(&istatus, imsg->data, sizeof(istatus));
1242 	if (datalen != sizeof(istatus) + istatus.reason_len)
1243 		return got_error(GOT_ERR_PRIVSEP_LEN);
1244 
1245 	reason = strndup(imsg->data + sizeof(istatus), istatus.reason_len);
1246 	if (reason == NULL) {
1247 		err = got_error_from_errno("strndup");
1248 		goto done;
1249 	}
1250 
1251 	if (err == NULL)
1252 		len = snprintf(buf, sizeof(buf), "unpack ok\n");
1253 	else
1254 		len = snprintf(buf, sizeof(buf), "unpack %s\n", reason);
1255 	if (len >= sizeof(buf)) {
1256 		err = got_error(GOT_ERR_NO_SPACE);
1257 		goto done;
1258 	}
1259 
1260 	err = got_pkt_writepkt(outfd, buf, len, chattygot);
1261 done:
1262 	free(reason);
1263 	return err;
1264 }
1265 
1266 static const struct got_error *
1267 recv_ref_update_ok(struct imsg *imsg, int outfd, int chattygot)
1268 {
1269 	const struct got_error *err = NULL;
1270 	struct gotd_imsg_ref_update_ok iok;
1271 	size_t datalen, len;
1272 	char buf[GOT_PKT_MAX];
1273 	char *refname = NULL;
1274 
1275 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1276 	if (datalen < sizeof(iok))
1277 		return got_error(GOT_ERR_PRIVSEP_LEN);
1278 	memcpy(&iok, imsg->data, sizeof(iok));
1279 	if (datalen != sizeof(iok) + iok.name_len)
1280 		return got_error(GOT_ERR_PRIVSEP_LEN);
1281 
1282 	memcpy(&iok, imsg->data, sizeof(iok));
1283 
1284 	refname = strndup(imsg->data + sizeof(iok), iok.name_len);
1285 	if (refname == NULL)
1286 		return got_error_from_errno("strndup");
1287 
1288 	len = snprintf(buf, sizeof(buf), "ok %s\n", refname);
1289 	if (len >= sizeof(buf)) {
1290 		err = got_error(GOT_ERR_NO_SPACE);
1291 		goto done;
1292 	}
1293 
1294 	err = got_pkt_writepkt(outfd, buf, len, chattygot);
1295 done:
1296 	free(refname);
1297 	return err;
1298 }
1299 
1300 static const struct got_error *
1301 recv_ref_update_ng(struct imsg *imsg, int outfd, int chattygot)
1302 {
1303 	const struct got_error *err = NULL;
1304 	struct gotd_imsg_ref_update_ng ing;
1305 	size_t datalen, len;
1306 	char buf[GOT_PKT_MAX];
1307 	char *refname = NULL, *reason = NULL;
1308 
1309 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1310 	if (datalen < sizeof(ing))
1311 		return got_error(GOT_ERR_PRIVSEP_LEN);
1312 	memcpy(&ing, imsg->data, sizeof(ing));
1313 	if (datalen != sizeof(ing) + ing.name_len + ing.reason_len)
1314 		return got_error(GOT_ERR_PRIVSEP_LEN);
1315 
1316 	memcpy(&ing, imsg->data, sizeof(ing));
1317 
1318 	refname = strndup(imsg->data + sizeof(ing), ing.name_len);
1319 	if (refname == NULL)
1320 		return got_error_from_errno("strndup");
1321 
1322 	reason = strndup(imsg->data + sizeof(ing) + ing.name_len,
1323 	    ing.reason_len);
1324 	if (reason == NULL) {
1325 		err = got_error_from_errno("strndup");
1326 		goto done;
1327 	}
1328 
1329 	len = snprintf(buf, sizeof(buf), "ng %s %s\n", refname, reason);
1330 	if (len >= sizeof(buf)) {
1331 		err = got_error(GOT_ERR_NO_SPACE);
1332 		goto done;
1333 	}
1334 
1335 	err = got_pkt_writepkt(outfd, buf, len, chattygot);
1336 done:
1337 	free(refname);
1338 	free(reason);
1339 	return err;
1340 }
1341 
1342 static const struct got_error *
1343 serve_write(int infd, int outfd, int gotd_sock, const char *repo_path,
1344     int chattygot)
1345 {
1346 	const struct got_error *err = NULL;
1347 	char buf[GOT_PKT_MAX];
1348 	struct imsgbuf ibuf;
1349 	enum protostate {
1350 		STATE_EXPECT_REF_UPDATE,
1351 		STATE_EXPECT_MORE_REF_UPDATES,
1352 		STATE_EXPECT_PACKFILE,
1353 		STATE_PACKFILE_RECEIVED,
1354 		STATE_REFS_UPDATED,
1355 	};
1356 	enum protostate curstate = STATE_EXPECT_REF_UPDATE;
1357 	struct imsg imsg;
1358 	int report_status = 0;
1359 
1360 	imsg_init(&ibuf, gotd_sock);
1361 	memset(&imsg, 0, sizeof(imsg));
1362 
1363 	err = announce_refs(outfd, &ibuf, 0, repo_path, chattygot);
1364 	if (err)
1365 		goto done;
1366 
1367 	while (curstate != STATE_EXPECT_PACKFILE) {
1368 		int n;
1369 		buf[0] = '\0';
1370 		err = got_pkt_readpkt(&n, infd, buf, sizeof(buf), chattygot);
1371 		if (err)
1372 			break;
1373 		if (n == 0) {
1374 			if (curstate != STATE_EXPECT_MORE_REF_UPDATES) {
1375 				err = got_error_msg(GOT_ERR_BAD_PACKET,
1376 				    "unexpected flush packet received");
1377 				goto done;
1378 			}
1379 			err = forward_flushpkt(&ibuf);
1380 			if (err)
1381 				goto done;
1382 			curstate = STATE_EXPECT_PACKFILE;
1383 		} else if (n >= (SHA1_DIGEST_STRING_LENGTH * 2) + 2) {
1384 			if (curstate != STATE_EXPECT_REF_UPDATE &&
1385 			    curstate != STATE_EXPECT_MORE_REF_UPDATES) {
1386 				err = got_error_msg(GOT_ERR_BAD_PACKET,
1387 				    "unexpected ref-update packet");
1388 				goto done;
1389 			}
1390 			if (curstate == STATE_EXPECT_REF_UPDATE) {
1391 				err = recv_ref_update(&report_status,
1392 				    outfd, &ibuf, buf, n, 1, chattygot);
1393 			} else {
1394 				err = recv_ref_update(NULL, outfd, &ibuf,
1395 				    buf, n, 0, chattygot);
1396 			}
1397 			if (err)
1398 				goto done;
1399 			curstate = STATE_EXPECT_MORE_REF_UPDATES;
1400 		} else {
1401 			err = got_error(GOT_ERR_BAD_PACKET);
1402 			goto done;
1403 		}
1404 	}
1405 
1406 	while (curstate != STATE_PACKFILE_RECEIVED) {
1407 		err = gotd_imsg_poll_recv(&imsg, &ibuf, 0);
1408 		if (err)
1409 			goto done;
1410 		switch (imsg.hdr.type) {
1411 		case GOTD_IMSG_ERROR:
1412 			err = gotd_imsg_recv_error(NULL, &imsg);
1413 			goto done;
1414 		case GOTD_IMSG_PACKFILE_PIPE:
1415 			err = recv_packfile(&imsg, infd);
1416 			if (err) {
1417 				if (err->code != GOT_ERR_EOF)
1418 					goto done;
1419 				/*
1420 				 * EOF is reported when the client hangs up,
1421 				 * which can happen with Git clients.
1422 				 * The socket should stay half-open so we
1423 				 * can still send our reports if requested.
1424 				 */
1425 				err = NULL;
1426 			}
1427 			curstate = STATE_PACKFILE_RECEIVED;
1428 			break;
1429 		default:
1430 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1431 			break;
1432 		}
1433 
1434 		imsg_free(&imsg);
1435 		if (err)
1436 			goto done;
1437 	}
1438 
1439 	while (curstate != STATE_REFS_UPDATED && err == NULL) {
1440 		err = gotd_imsg_poll_recv(&imsg, &ibuf, 0);
1441 		if (err)
1442 			break;
1443 		switch (imsg.hdr.type) {
1444 		case GOTD_IMSG_ERROR:
1445 			err = gotd_imsg_recv_error(NULL, &imsg);
1446 			break;
1447 		case GOTD_IMSG_PACKFILE_STATUS:
1448 			if (!report_status)
1449 				break;
1450 			err = report_unpack_status(&imsg, outfd, chattygot);
1451 			break;
1452 		case GOTD_IMSG_REF_UPDATE_OK:
1453 			if (!report_status)
1454 				break;
1455 			err = recv_ref_update_ok(&imsg, outfd, chattygot);
1456 			break;
1457 		case GOTD_IMSG_REF_UPDATE_NG:
1458 			if (!report_status)
1459 				break;
1460 			err = recv_ref_update_ng(&imsg, outfd, chattygot);
1461 			break;
1462 		case GOTD_IMSG_REFS_UPDATED:
1463 			curstate = STATE_REFS_UPDATED;
1464 			err = got_pkt_flushpkt(outfd, chattygot);
1465 			break;
1466 		default:
1467 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1468 			break;
1469 		}
1470 
1471 		imsg_free(&imsg);
1472 	}
1473 done:
1474 	imsg_clear(&ibuf);
1475 	if (err)
1476 		echo_error(err, outfd, chattygot);
1477 	return err;
1478 }
1479 
1480 const struct got_error *
1481 got_serve(int infd, int outfd, const char *gitcmd, int gotd_sock, int chattygot)
1482 {
1483 	const struct got_error *err = NULL;
1484 	char *command = NULL, *repo_path = NULL;
1485 
1486 	err = parse_command(&command, &repo_path, gitcmd);
1487 	if (err)
1488 		return err;
1489 
1490 	if (strcmp(command, GOT_SERVE_CMD_FETCH) == 0)
1491 		err = serve_read(infd, outfd, gotd_sock, repo_path, chattygot);
1492 	else if (strcmp(command, GOT_SERVE_CMD_SEND) == 0)
1493 		err = serve_write(infd, outfd, gotd_sock, repo_path, chattygot);
1494 	else
1495 		err = got_error(GOT_ERR_BAD_PACKET);
1496 
1497 	free(command);
1498 	free(repo_path);
1499 	return err;
1500 }