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Date:: Thu Feb 23 14:21:01 2023 UTC
Message:: provide functions to parse/serialize different hashes it abstracts over the hash type and ensures that object ids are zero'ed before their sha1 digest is written. Needed by the incoming sha256 support. ok stsp@
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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 <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 const struct got_error *
68 got_serve_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 	const char *line = GOT_SHA1_STRING_ZERO " capabilities^{}";
227 	char buf[GOT_PKT_MAX];
228 	size_t len, capalen = 0;
229 
230 	len = strlcpy(buf, line, sizeof(buf));
231 	if (len >= sizeof(buf))
232 		return got_error(GOT_ERR_NO_SPACE);
233 
234 	if (client_is_reading) {
235 		err = got_gitproto_append_capabilities(&capalen, buf, len,
236 		    sizeof(buf), read_capabilities, nitems(read_capabilities));
237 		if (err)
238 			return err;
239 	} else {
240 		err = got_gitproto_append_capabilities(&capalen, buf, len,
241 		    sizeof(buf), write_capabilities,
242 		    nitems(write_capabilities));
243 		if (err)
244 			return err;
245 	}
246 
247 	return got_pkt_writepkt(outfd, buf, len + capalen, chattygot);
248 }
249 
250 static void
251 echo_error(const struct got_error *err, int outfd, int chattygot)
252 {
253 	char buf[4 + GOT_ERR_MAX_MSG_SIZE];
254 	size_t len;
255 
256 	/*
257 	 * Echo the error to the client on a pkt-line.
258 	 * The client should then terminate its session.
259 	 */
260 	buf[0] = 'E'; buf[1] = 'R'; buf[2] = 'R'; buf[3] = ' '; buf[4] = '\0';
261 	len = strlcat(buf, err->msg, sizeof(buf));
262 	got_pkt_writepkt(outfd, buf, len, chattygot);
263 }
264 
265 static const struct got_error *
266 announce_refs(int outfd, struct imsgbuf *ibuf, int client_is_reading,
267     const char *repo_path, int chattygot)
268 {
269 	const struct got_error *err = NULL;
270 	struct imsg imsg;
271 	size_t datalen;
272 	struct gotd_imsg_list_refs lsref;
273 	struct gotd_imsg_reflist ireflist;
274 	struct gotd_imsg_ref iref;
275 	struct gotd_imsg_symref isymref;
276 	size_t nrefs = 0;
277 	int have_nrefs = 0, sent_capabilities = 0;
278 	char *symrefname = NULL, *symreftarget = NULL, *symrefstr = NULL;
279 	char *refname = NULL;
280 
281 	memset(&imsg, 0, sizeof(imsg));
282 	memset(&lsref, 0, sizeof(lsref));
283 
284 	if (strlcpy(lsref.repo_name, repo_path, sizeof(lsref.repo_name)) >=
285 	    sizeof(lsref.repo_name))
286 		return got_error(GOT_ERR_NO_SPACE);
287 	lsref.client_is_reading = client_is_reading;
288 
289 	if (imsg_compose(ibuf, GOTD_IMSG_LIST_REFS, 0, 0, -1,
290 	    &lsref, sizeof(lsref)) == -1)
291 		return got_error_from_errno("imsg_compose LIST_REFS");
292 
293 	err = gotd_imsg_flush(ibuf);
294 	if (err)
295 		return err;
296 
297 	while (!have_nrefs || nrefs > 0) {
298 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
299 		if (err)
300 			goto done;
301 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
302 		switch (imsg.hdr.type) {
303 		case GOTD_IMSG_ERROR:
304 			err = gotd_imsg_recv_error(NULL, &imsg);
305 			goto done;
306 		case GOTD_IMSG_REFLIST:
307 			if (have_nrefs || nrefs > 0) {
308 				err = got_error(GOT_ERR_PRIVSEP_MSG);
309 				goto done;
310 			}
311 			if (datalen != sizeof(ireflist)) {
312 				err = got_error(GOT_ERR_PRIVSEP_MSG);
313 				goto done;
314 			}
315 			memcpy(&ireflist, imsg.data, sizeof(ireflist));
316 			nrefs = ireflist.nrefs;
317 			have_nrefs = 1;
318 			if (nrefs == 0)
319 				err = send_zero_refs(outfd, client_is_reading,
320 				    chattygot);
321 			break;
322 		case GOTD_IMSG_REF:
323 			if (!have_nrefs || nrefs == 0) {
324 				err = got_error(GOT_ERR_PRIVSEP_MSG);
325 				goto done;
326 			}
327 			if (datalen < sizeof(iref)) {
328 				err = got_error(GOT_ERR_PRIVSEP_MSG);
329 				goto done;
330 			}
331 			memcpy(&iref, imsg.data, sizeof(iref));
332 			if (datalen != sizeof(iref) + iref.name_len) {
333 				err = got_error(GOT_ERR_PRIVSEP_LEN);
334 				goto done;
335 			}
336 			refname = strndup(imsg.data + sizeof(iref),
337 			    iref.name_len);
338 			if (refname == NULL) {
339 				err = got_error_from_errno("strndup");
340 				goto done;
341 			}
342 			err = send_ref(outfd, iref.id, refname,
343 			    !sent_capabilities, client_is_reading,
344 			    NULL, chattygot);
345 			free(refname);
346 			refname = NULL;
347 			if (err)
348 				goto done;
349 			sent_capabilities = 1;
350 			if (nrefs > 0)
351 				nrefs--;
352 			break;
353 		case GOTD_IMSG_SYMREF:
354 			if (!have_nrefs || nrefs == 0) {
355 				err = got_error(GOT_ERR_PRIVSEP_MSG);
356 				goto done;
357 			}
358 			if (datalen < sizeof(isymref)) {
359 				err = got_error(GOT_ERR_PRIVSEP_LEN);
360 				goto done;
361 			}
362 			memcpy(&isymref, imsg.data, sizeof(isymref));
363 			if (datalen != sizeof(isymref) + isymref.name_len +
364 			    isymref.target_len) {
365 				err = got_error(GOT_ERR_PRIVSEP_LEN);
366 				goto done;
367 			}
368 
369 			/*
370 			 * For now, we only announce one symbolic ref,
371 			 * as part of our capability advertisement.
372 			 */
373 			if (sent_capabilities || symrefstr != NULL ||
374 			    symrefname != NULL || symreftarget != NULL)
375 				break;
376 
377 			symrefname = strndup(imsg.data + sizeof(isymref),
378 			    isymref.name_len);
379 			if (symrefname == NULL) {
380 				err = got_error_from_errno("malloc");
381 				goto done;
382 			}
383 
384 			symreftarget = strndup(
385 			    imsg.data + sizeof(isymref) + isymref.name_len,
386 			    isymref.target_len);
387 			if (symreftarget == NULL) {
388 				err = got_error_from_errno("strndup");
389 				goto done;
390 			}
391 
392 			if (asprintf(&symrefstr, "%s:%s", symrefname,
393 			    symreftarget) == -1) {
394 				err = got_error_from_errno("asprintf");
395 				goto done;
396 			}
397 			err = send_ref(outfd, isymref.target_id, symrefname,
398 			    !sent_capabilities, client_is_reading, symrefstr,
399 			    chattygot);
400 			free(refname);
401 			refname = NULL;
402 			if (err)
403 				goto done;
404 			sent_capabilities = 1;
405 			if (nrefs > 0)
406 				nrefs--;
407 			break;
408 		default:
409 			err = got_error(GOT_ERR_PRIVSEP_MSG);
410 			break;
411 		}
412 
413 		imsg_free(&imsg);
414 	}
415 
416 	err = got_pkt_flushpkt(outfd, chattygot);
417 	if (err)
418 		goto done;
419 done:
420 	free(symrefstr);
421 	free(symrefname);
422 	free(symreftarget);
423 	return err;
424 }
425 
426 static const struct got_error *
427 parse_want_line(char **common_capabilities, uint8_t *id, char *buf, size_t len)
428 {
429 	const struct got_error *err;
430 	char *id_str = NULL, *client_capabilities = NULL;
431 
432 	err = got_gitproto_parse_want_line(&id_str,
433 	    &client_capabilities, buf, len);
434 	if (err)
435 		return err;
436 
437 	if (!got_parse_hash_digest(id, id_str, GOT_HASH_SHA1)) {
438 		err = got_error_msg(GOT_ERR_BAD_PACKET,
439 		    "want-line with bad object ID");
440 		goto done;
441 	}
442 
443 	if (client_capabilities) {
444 		err = got_gitproto_match_capabilities(common_capabilities,
445 		    NULL, client_capabilities, read_capabilities,
446 		    nitems(read_capabilities));
447 		if (err)
448 			goto done;
449 	}
450 done:
451 	free(id_str);
452 	free(client_capabilities);
453 	return err;
454 }
455 
456 static const struct got_error *
457 parse_have_line(uint8_t *id, char *buf, size_t len)
458 {
459 	const struct got_error *err;
460 	char *id_str = NULL;
461 
462 	err = got_gitproto_parse_have_line(&id_str, buf, len);
463 	if (err)
464 		return err;
465 
466 	if (!got_parse_hash_digest(id, id_str, GOT_HASH_SHA1)) {
467 		err = got_error_msg(GOT_ERR_BAD_PACKET,
468 		    "have-line with bad object ID");
469 		goto done;
470 	}
471 done:
472 	free(id_str);
473 	return err;
474 }
475 
476 static const struct got_error *
477 send_capability(struct got_capability *capa, struct imsgbuf *ibuf)
478 {
479 	const struct got_error *err = NULL;
480 	struct gotd_imsg_capability icapa;
481 	size_t len;
482 	struct ibuf *wbuf;
483 
484 	memset(&icapa, 0, sizeof(icapa));
485 
486 	icapa.key_len = strlen(capa->key);
487 	len = sizeof(icapa) + icapa.key_len;
488 	if (capa->value) {
489 		icapa.value_len = strlen(capa->value);
490 		len += icapa.value_len;
491 	}
492 
493 	wbuf = imsg_create(ibuf, GOTD_IMSG_CAPABILITY, 0, 0, len);
494 	if (wbuf == NULL) {
495 		err = got_error_from_errno("imsg_create CAPABILITY");
496 		return err;
497 	}
498 
499 	if (imsg_add(wbuf, &icapa, sizeof(icapa)) == -1)
500 		return got_error_from_errno("imsg_add CAPABILITY");
501 	if (imsg_add(wbuf, capa->key, icapa.key_len) == -1)
502 		return got_error_from_errno("imsg_add CAPABILITY");
503 	if (capa->value) {
504 		if (imsg_add(wbuf, capa->value, icapa.value_len) == -1)
505 			return got_error_from_errno("imsg_add CAPABILITY");
506 	}
507 
508 	wbuf->fd = -1;
509 	imsg_close(ibuf, wbuf);
510 
511 	return NULL;
512 }
513 
514 static const struct got_error *
515 send_capabilities(int *use_sidebands, int *report_status,
516     char *capabilities_str, struct imsgbuf *ibuf)
517 {
518 	const struct got_error *err = NULL;
519 	struct gotd_imsg_capabilities icapas;
520 	struct got_capability *capa = NULL;
521 	size_t ncapa, i;
522 
523 	err = got_gitproto_split_capabilities_str(&capa, &ncapa,
524 	    capabilities_str);
525 	if (err)
526 		return err;
527 
528 	icapas.ncapabilities = ncapa;
529 	if (imsg_compose(ibuf, GOTD_IMSG_CAPABILITIES, 0, 0, -1,
530 	    &icapas, sizeof(icapas)) == -1) {
531 		err = got_error_from_errno("imsg_compose IMSG_CAPABILITIES");
532 		goto done;
533 	}
534 
535 	for (i = 0; i < ncapa; i++) {
536 		err = send_capability(&capa[i], ibuf);
537 		if (err)
538 			goto done;
539 		if (use_sidebands &&
540 		    strcmp(capa[i].key, GOT_CAPA_SIDE_BAND_64K) == 0)
541 			*use_sidebands = 1;
542 		if (report_status &&
543 		    strcmp(capa[i].key, GOT_CAPA_REPORT_STATUS) == 0)
544 			*report_status = 1;
545 	}
546 done:
547 	free(capa);
548 	return err;
549 }
550 
551 static const struct got_error *
552 forward_flushpkt(struct imsgbuf *ibuf)
553 {
554 	if (imsg_compose(ibuf, GOTD_IMSG_FLUSH, 0, 0, -1, NULL, 0) == -1)
555 		return got_error_from_errno("imsg_compose FLUSH");
556 
557 	return gotd_imsg_flush(ibuf);
558 }
559 
560 static const struct got_error *
561 recv_ack(struct imsg *imsg, uint8_t *expected_id)
562 {
563 	struct gotd_imsg_ack iack;
564 	size_t datalen;
565 
566 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
567 	if (datalen != sizeof(iack))
568 		return got_error(GOT_ERR_PRIVSEP_LEN);
569 
570 	memcpy(&iack, imsg->data, sizeof(iack));
571 	if (memcmp(iack.object_id, expected_id, SHA1_DIGEST_LENGTH) != 0)
572 		return got_error(GOT_ERR_BAD_OBJ_ID);
573 
574 	return NULL;
575 }
576 
577 static const struct got_error *
578 recv_nak(struct imsg *imsg, uint8_t *expected_id)
579 {
580 	struct gotd_imsg_ack inak;
581 	size_t datalen;
582 
583 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
584 	if (datalen != sizeof(inak))
585 		return got_error(GOT_ERR_PRIVSEP_LEN);
586 
587 	memcpy(&inak, imsg->data, sizeof(inak));
588 	if (memcmp(inak.object_id, expected_id, SHA1_DIGEST_LENGTH) != 0)
589 		return got_error(GOT_ERR_BAD_OBJ_ID);
590 
591 	return NULL;
592 }
593 
594 
595 static const struct got_error *
596 recv_want(int *use_sidebands, int outfd, struct imsgbuf *ibuf,
597     char *buf, size_t len, int expect_capabilities, int chattygot)
598 {
599 	const struct got_error *err;
600 	struct gotd_imsg_want iwant;
601 	char *capabilities_str;
602 	int done = 0;
603 	struct imsg imsg;
604 
605 	memset(&iwant, 0, sizeof(iwant));
606 	memset(&imsg, 0, sizeof(imsg));
607 
608 	err = parse_want_line(&capabilities_str, iwant.object_id, buf, len);
609 	if (err)
610 		return err;
611 
612 	if (capabilities_str) {
613 		if (!expect_capabilities) {
614 			err = got_error_msg(GOT_ERR_BAD_PACKET,
615 			    "unexpected capability announcement received");
616 			goto done;
617 		}
618 		err = send_capabilities(use_sidebands, NULL, capabilities_str,
619 		    ibuf);
620 		if (err)
621 			goto done;
622 
623 	}
624 
625 	if (imsg_compose(ibuf, GOTD_IMSG_WANT, 0, 0, -1,
626 	    &iwant, sizeof(iwant)) == -1) {
627 		err = got_error_from_errno("imsg_compose WANT");
628 		goto done;
629 	}
630 
631 	err = gotd_imsg_flush(ibuf);
632 	if (err)
633 		goto done;
634 
635 	/*
636 	 * Wait for an ACK, or an error in case the desired object
637 	 * does not exist.
638 	 */
639 	while (!done && err == NULL) {
640 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
641 		if (err)
642 			break;
643 		switch (imsg.hdr.type) {
644 		case GOTD_IMSG_ERROR:
645 			err = gotd_imsg_recv_error(NULL, &imsg);
646 			break;
647 		case GOTD_IMSG_ACK:
648 			err = recv_ack(&imsg, iwant.object_id);
649 			if (err)
650 				break;
651 			done = 1;
652 			break;
653 		default:
654 			err = got_error(GOT_ERR_PRIVSEP_MSG);
655 			break;
656 		}
657 
658 		imsg_free(&imsg);
659 	}
660 done:
661 	free(capabilities_str);
662 	return err;
663 }
664 
665 static const struct got_error *
666 send_ack(int outfd, uint8_t *id, int chattygot)
667 {
668 	char hex[SHA1_DIGEST_STRING_LENGTH];
669 	char buf[GOT_PKT_MAX];
670 	int len;
671 
672 	if (got_sha1_digest_to_str(id, hex, sizeof(hex)) == NULL)
673 		return got_error(GOT_ERR_BAD_OBJ_ID);
674 
675 	len = snprintf(buf, sizeof(buf), "ACK %s\n", hex);
676 	if (len >= sizeof(buf))
677 		return got_error(GOT_ERR_NO_SPACE);
678 
679 	return got_pkt_writepkt(outfd, buf, len, chattygot);
680 }
681 
682 static const struct got_error *
683 send_nak(int outfd, int chattygot)
684 {
685 	char buf[5];
686 	int len;
687 
688 	len = snprintf(buf, sizeof(buf), "NAK\n");
689 	if (len >= sizeof(buf))
690 		return got_error(GOT_ERR_NO_SPACE);
691 
692 	return got_pkt_writepkt(outfd, buf, len, chattygot);
693 }
694 
695 static const struct got_error *
696 recv_have(int *have_ack, int outfd, struct imsgbuf *ibuf, char *buf,
697     size_t len, int chattygot)
698 {
699 	const struct got_error *err;
700 	struct gotd_imsg_have ihave;
701 	int done = 0;
702 	struct imsg imsg;
703 
704 	memset(&ihave, 0, sizeof(ihave));
705 	memset(&imsg, 0, sizeof(imsg));
706 
707 	err = parse_have_line(ihave.object_id, buf, len);
708 	if (err)
709 		return err;
710 
711 	if (imsg_compose(ibuf, GOTD_IMSG_HAVE, 0, 0, -1,
712 	    &ihave, sizeof(ihave)) == -1)
713 		return got_error_from_errno("imsg_compose HAVE");
714 
715 	err = gotd_imsg_flush(ibuf);
716 	if (err)
717 		return err;
718 
719 	/*
720 	 * Wait for an ACK or a NAK, indicating whether a common
721 	 * commit object has been found.
722 	 */
723 	while (!done && err == NULL) {
724 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
725 		if (err)
726 			return err;
727 		switch (imsg.hdr.type) {
728 		case GOTD_IMSG_ERROR:
729 			err = gotd_imsg_recv_error(NULL, &imsg);
730 			break;
731 		case GOTD_IMSG_ACK:
732 			err = recv_ack(&imsg, ihave.object_id);
733 			if (err)
734 				break;
735 			if (!*have_ack) {
736 				err = send_ack(outfd, ihave.object_id,
737 				    chattygot);
738 				if (err)
739 					return err;
740 				*have_ack = 1;
741 			}
742 			done = 1;
743 			break;
744 		case GOTD_IMSG_NAK:
745 			err = recv_nak(&imsg, ihave.object_id);
746 			if (err)
747 				break;
748 			done = 1;
749 			break;
750 		default:
751 			err = got_error(GOT_ERR_PRIVSEP_MSG);
752 			break;
753 		}
754 
755 		imsg_free(&imsg);
756 	}
757 
758 	return err;
759 }
760 
761 static const struct got_error *
762 recv_done(int *packfd, int outfd, struct imsgbuf *ibuf, int chattygot)
763 {
764 	const struct got_error *err;
765 	struct imsg imsg;
766 
767 	*packfd = -1;
768 
769 	if (imsg_compose(ibuf, GOTD_IMSG_DONE, 0, 0, -1, NULL, 0) == -1)
770 		return got_error_from_errno("imsg_compose DONE");
771 
772 	err = gotd_imsg_flush(ibuf);
773 	if (err)
774 		return err;
775 
776 	while (*packfd == -1 && err == NULL) {
777 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
778 		if (err)
779 			break;
780 
781 		switch (imsg.hdr.type) {
782 		case GOTD_IMSG_ERROR:
783 			err = gotd_imsg_recv_error(NULL, &imsg);
784 			break;
785 		case GOTD_IMSG_PACKFILE_PIPE:
786 			if (imsg.fd != -1)
787 				*packfd = imsg.fd;
788 			else
789 				err = got_error(GOT_ERR_PRIVSEP_NO_FD);
790 			break;
791 		default:
792 			err = got_error(GOT_ERR_PRIVSEP_MSG);
793 			break;
794 		}
795 
796 		imsg_free(&imsg);
797 	}
798 
799 	return err;
800 }
801 
802 static const struct got_error *
803 relay_progress_reports(struct imsgbuf *ibuf, int outfd, int chattygot)
804 {
805 	const struct got_error *err = NULL;
806 	int pack_starting = 0;
807 	struct gotd_imsg_packfile_progress iprog;
808 	char buf[GOT_PKT_MAX];
809 	struct imsg imsg;
810 	size_t datalen;
811 	int p_deltify = 0, n;
812 	const char *eol = "\r";
813 
814 	memset(&imsg, 0, sizeof(imsg));
815 
816 	while (!pack_starting && err == NULL) {
817 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
818 		if (err)
819 			break;
820 
821 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
822 		switch (imsg.hdr.type) {
823 		case GOTD_IMSG_ERROR:
824 			err = gotd_imsg_recv_error(NULL, &imsg);
825 			break;
826 		case GOTD_IMSG_PACKFILE_READY:
827 			eol = "\n";
828 			pack_starting = 1;
829 			/* fallthrough */
830 		case GOTD_IMSG_PACKFILE_PROGRESS:
831 			if (datalen != sizeof(iprog)) {
832 				err = got_error(GOT_ERR_PRIVSEP_LEN);
833 				break;
834 			}
835 			memcpy(&iprog, imsg.data, sizeof(iprog));
836 			if (iprog.nobj_total > 0) {
837 				p_deltify = (iprog.nobj_deltify * 100) /
838 				    iprog.nobj_total;
839 			}
840 			buf[0] = GOT_SIDEBAND_PROGRESS_INFO;
841 			n = snprintf(&buf[1], sizeof(buf) - 1,
842 			    "%d commits colored, "
843 			    "%d objects found, "
844 			    "deltify %d%%%s",
845 			    iprog.ncolored,
846 			    iprog.nfound,
847 			    p_deltify, eol);
848 			if (n >= sizeof(buf) - 1)
849 				break;
850 			err = got_pkt_writepkt(outfd, buf, 1 + n, chattygot);
851 			break;
852 		default:
853 			err = got_error(GOT_ERR_PRIVSEP_MSG);
854 			break;
855 		}
856 
857 		imsg_free(&imsg);
858 	}
859 
860 	return err;
861 }
862 
863 static const struct got_error *
864 serve_read(int infd, int outfd, int gotd_sock, const char *repo_path,
865     int chattygot)
866 {
867 	const struct got_error *err = NULL;
868 	char buf[GOT_PKT_MAX];
869 	struct imsgbuf ibuf;
870 	enum protostate {
871 		STATE_EXPECT_WANT,
872 		STATE_EXPECT_MORE_WANT,
873 		STATE_EXPECT_HAVE,
874 		STATE_EXPECT_DONE,
875 		STATE_DONE,
876 	};
877 	enum protostate curstate = STATE_EXPECT_WANT;
878 	int have_ack = 0, use_sidebands = 0, seen_have = 0;
879 	int packfd = -1;
880 	size_t pack_chunksize;
881 
882 	imsg_init(&ibuf, gotd_sock);
883 
884 	err = announce_refs(outfd, &ibuf, 1, repo_path, chattygot);
885 	if (err)
886 		goto done;
887 
888 	while (curstate != STATE_DONE) {
889 		int n;
890 		buf[0] = '\0';
891 		err = got_pkt_readpkt(&n, infd, buf, sizeof(buf), chattygot);
892 		if (err)
893 			goto done;
894 		if (n == 0) {
895 			if (curstate != STATE_EXPECT_WANT &&
896 			    curstate != STATE_EXPECT_MORE_WANT &&
897 			    curstate != STATE_EXPECT_HAVE &&
898 			    curstate != STATE_EXPECT_DONE) {
899 				err = got_error_msg(GOT_ERR_BAD_PACKET,
900 				    "unexpected flush packet received");
901 				goto done;
902 			}
903 
904 			if (curstate == STATE_EXPECT_WANT) {
905 				ssize_t r;
906 				/*
907 				 * If the client does not want to fetch
908 				 * anything we should receive a flush
909 				 * packet followed by EOF.
910 				 */
911 				r = read(infd, buf, sizeof(buf));
912 				if (r == -1) {
913 					err = got_error_from_errno("read");
914 					goto done;
915 				}
916 				if (r == 0) /* EOF */
917 					goto done;
918 
919 				/* Zero-length field followed by payload. */
920 				err = got_error_msg(GOT_ERR_BAD_PACKET,
921 				    "unexpected flush packet received");
922 				goto done;
923 			}
924 
925 			if (curstate == STATE_EXPECT_WANT ||
926 			    curstate == STATE_EXPECT_MORE_WANT ||
927 			    curstate == STATE_EXPECT_HAVE) {
928 				err = forward_flushpkt(&ibuf);
929 				if (err)
930 					goto done;
931 			}
932 			if (curstate == STATE_EXPECT_HAVE && !have_ack) {
933 				err = send_nak(outfd, chattygot);
934 				if (err)
935 					goto done;
936 			}
937 			if (curstate == STATE_EXPECT_MORE_WANT)
938 				curstate = STATE_EXPECT_HAVE;
939 			else
940 				curstate = STATE_EXPECT_DONE;
941 		} else if (n >= 5 && strncmp(buf, "want ", 5) == 0) {
942 			if (curstate != STATE_EXPECT_WANT &&
943 			    curstate != STATE_EXPECT_MORE_WANT) {
944 				err = got_error_msg(GOT_ERR_BAD_PACKET,
945 				    "unexpected 'want' packet");
946 				goto done;
947 			}
948 			err = recv_want(&use_sidebands, outfd, &ibuf, buf, n,
949 			    curstate == STATE_EXPECT_WANT ? 1 : 0, chattygot);
950 			if (err)
951 				goto done;
952 			if (curstate == STATE_EXPECT_WANT)
953 				curstate = STATE_EXPECT_MORE_WANT;
954 		} else if (n >= 5 && strncmp(buf, "have ", 5) == 0) {
955 			if (curstate != STATE_EXPECT_HAVE &&
956 			    curstate != STATE_EXPECT_DONE) {
957 				err = got_error_msg(GOT_ERR_BAD_PACKET,
958 				    "unexpected 'have' packet");
959 				goto done;
960 			}
961 			if (curstate == STATE_EXPECT_HAVE) {
962 				err = recv_have(&have_ack, outfd, &ibuf,
963 				    buf, n, chattygot);
964 				if (err)
965 					goto done;
966 				seen_have = 1;
967 				if (have_ack)
968 					curstate = STATE_EXPECT_DONE;
969 			}
970 		} else if (n == 5 && strncmp(buf, "done\n", 5) == 0) {
971 			if (curstate != STATE_EXPECT_HAVE &&
972 			    curstate != STATE_EXPECT_DONE) {
973 				err = got_error_msg(GOT_ERR_BAD_PACKET,
974 				    "unexpected 'done' packet");
975 				goto done;
976 			}
977 			err = recv_done(&packfd, outfd, &ibuf, chattygot);
978 			if (err)
979 				goto done;
980 			curstate = STATE_DONE;
981 			break;
982 		} else {
983 			err = got_error(GOT_ERR_BAD_PACKET);
984 			goto done;
985 		}
986 	}
987 
988 	if (!seen_have) {
989 		err = send_nak(outfd, chattygot);
990 		if (err)
991 			goto done;
992 	}
993 
994 	if (use_sidebands) {
995 		err = relay_progress_reports(&ibuf, outfd, chattygot);
996 		if (err)
997 			goto done;
998 		pack_chunksize = GOT_SIDEBAND_64K_PACKFILE_DATA_MAX;
999 	} else
1000 		pack_chunksize = sizeof(buf);
1001 
1002 	for (;;) {
1003 		ssize_t r;
1004 
1005 		r = read(packfd, use_sidebands ? &buf[1] : buf,
1006 		    pack_chunksize);
1007 		if (r == -1) {
1008 			err = got_error_from_errno("read");
1009 			break;
1010 		} else if (r == 0) {
1011 			err = got_pkt_flushpkt(outfd, chattygot);
1012 			break;
1013 		}
1014 
1015 		if (use_sidebands) {
1016 			buf[0] = GOT_SIDEBAND_PACKFILE_DATA;
1017 			err = got_pkt_writepkt(outfd, buf, 1 + r, chattygot);
1018 			if (err)
1019 				break;
1020 		} else {
1021 			err = got_poll_write_full(outfd, buf, r);
1022 			if (err) {
1023 				if (err->code == GOT_ERR_EOF)
1024 					err = NULL;
1025 				break;
1026 			}
1027 		}
1028 	}
1029 done:
1030 	imsg_clear(&ibuf);
1031 	if (packfd != -1 && close(packfd) == -1 && err == NULL)
1032 		err = got_error_from_errno("close");
1033 	if (err)
1034 		echo_error(err, outfd, chattygot);
1035 	return err;
1036 }
1037 
1038 static const struct got_error *
1039 parse_ref_update_line(char **common_capabilities, char **refname,
1040     uint8_t *old_id, uint8_t *new_id, char *buf, size_t len)
1041 {
1042 	const struct got_error *err;
1043 	char *old_id_str = NULL, *new_id_str = NULL;
1044 	char *client_capabilities = NULL;
1045 
1046 	*refname = NULL;
1047 
1048 	err = got_gitproto_parse_ref_update_line(&old_id_str, &new_id_str,
1049 	    refname, &client_capabilities, buf, len);
1050 	if (err)
1051 		return err;
1052 
1053 	if (!got_parse_hash_digest(old_id, old_id_str, GOT_HASH_SHA1) ||
1054 	    !got_parse_hash_digest(new_id, new_id_str, GOT_HASH_SHA1)) {
1055 		err = got_error_msg(GOT_ERR_BAD_PACKET,
1056 		    "ref-update with bad object ID");
1057 		goto done;
1058 	}
1059 	if (!got_ref_name_is_valid(*refname)) {
1060 		err = got_error_msg(GOT_ERR_BAD_PACKET,
1061 		    "ref-update with bad reference name");
1062 		goto done;
1063 	}
1064 
1065 	if (client_capabilities) {
1066 		err = got_gitproto_match_capabilities(common_capabilities,
1067 		    NULL, client_capabilities, write_capabilities,
1068 		    nitems(write_capabilities));
1069 		if (err)
1070 			goto done;
1071 	}
1072 done:
1073 	free(old_id_str);
1074 	free(new_id_str);
1075 	free(client_capabilities);
1076 	if (err) {
1077 		free(*refname);
1078 		*refname = NULL;
1079 	}
1080 	return err;
1081 }
1082 
1083 static const struct got_error *
1084 recv_ref_update(int *report_status, int outfd, struct imsgbuf *ibuf,
1085     char *buf, size_t len, int expect_capabilities, int chattygot)
1086 {
1087 	const struct got_error *err;
1088 	struct gotd_imsg_ref_update iref;
1089 	struct ibuf *wbuf;
1090 	char *capabilities_str = NULL, *refname = NULL;
1091 	int done = 0;
1092 	struct imsg imsg;
1093 
1094 	memset(&iref, 0, sizeof(iref));
1095 	memset(&imsg, 0, sizeof(imsg));
1096 
1097 	err = parse_ref_update_line(&capabilities_str, &refname,
1098 	    iref.old_id, iref.new_id, buf, len);
1099 	if (err)
1100 		return err;
1101 
1102 	if (capabilities_str) {
1103 		if (!expect_capabilities) {
1104 			err = got_error_msg(GOT_ERR_BAD_PACKET,
1105 			    "unexpected capability announcement received");
1106 			goto done;
1107 		}
1108 		err = send_capabilities(NULL, report_status, capabilities_str,
1109 		    ibuf);
1110 		if (err)
1111 			goto done;
1112 	}
1113 
1114 	iref.name_len = strlen(refname);
1115 	len = sizeof(iref) + iref.name_len;
1116 	wbuf = imsg_create(ibuf, GOTD_IMSG_REF_UPDATE, 0, 0, len);
1117 	if (wbuf == NULL) {
1118 		err = got_error_from_errno("imsg_create REF_UPDATE");
1119 		goto done;
1120 	}
1121 
1122 	if (imsg_add(wbuf, &iref, sizeof(iref)) == -1)
1123 		return got_error_from_errno("imsg_add REF_UPDATE");
1124 	if (imsg_add(wbuf, refname, iref.name_len) == -1)
1125 		return got_error_from_errno("imsg_add REF_UPDATE");
1126 	wbuf->fd = -1;
1127 	imsg_close(ibuf, wbuf);
1128 
1129 	err = gotd_imsg_flush(ibuf);
1130 	if (err)
1131 		goto done;
1132 
1133 	/* Wait for ACK or an error. */
1134 	while (!done && err == NULL) {
1135 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
1136 		if (err)
1137 			break;
1138 		switch (imsg.hdr.type) {
1139 		case GOTD_IMSG_ERROR:
1140 			err = gotd_imsg_recv_error(NULL, &imsg);
1141 			break;
1142 		case GOTD_IMSG_ACK:
1143 			err = recv_ack(&imsg, iref.new_id);
1144 			if (err)
1145 				break;
1146 			done = 1;
1147 			break;
1148 		default:
1149 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1150 			break;
1151 		}
1152 
1153 		imsg_free(&imsg);
1154 	}
1155 done:
1156 	free(capabilities_str);
1157 	free(refname);
1158 	return err;
1159 }
1160 
1161 static const struct got_error *
1162 recv_packfile(struct imsg *imsg, int infd)
1163 {
1164 	const struct got_error *err = NULL;
1165 	size_t datalen;
1166 	int packfd;
1167 	char buf[GOT_PKT_MAX];
1168 	int pack_done = 0;
1169 
1170 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1171 	if (datalen != 0)
1172 		return got_error(GOT_ERR_PRIVSEP_MSG);
1173 
1174 	if (imsg->fd == -1)
1175 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
1176 
1177 	packfd = imsg->fd;
1178 	while (!pack_done) {
1179 		ssize_t r = 0;
1180 
1181 		err = got_poll_fd(infd, POLLIN, 1);
1182 		if (err) {
1183 			if (err->code != GOT_ERR_TIMEOUT)
1184 				break;
1185 			err = NULL;
1186 		} else {
1187 			r = read(infd, buf, sizeof(buf));
1188 			if (r == -1) {
1189 				err = got_error_from_errno("read");
1190 				break;
1191 			}
1192 			if (r == 0) {
1193 				/*
1194 				 * Git clients hang up their side of the
1195 				 * connection after sending the pack file.
1196 				 */
1197 				err = NULL;
1198 				pack_done = 1;
1199 				break;
1200 			}
1201 		}
1202 
1203 		if (r == 0) {
1204 			/* Detect gotd(8) closing the pack pipe when done. */
1205 			err = got_poll_fd(packfd, POLLOUT, 1);
1206 			if (err) {
1207 				if (err->code != GOT_ERR_EOF)
1208 					break;
1209 				err = NULL;
1210 				pack_done = 1;
1211 			}
1212 		} else {
1213 			/* Write pack data and/or detect pipe being closed. */
1214 			err = got_poll_write_full(packfd, buf, r);
1215 			if (err) {
1216 				if (err->code == GOT_ERR_EOF)
1217 					err = NULL;
1218 				break;
1219 			}
1220 		}
1221 	}
1222 
1223 	close(packfd);
1224 	return err;
1225 }
1226 
1227 static const struct got_error *
1228 report_unpack_status(struct imsg *imsg, int outfd, int chattygot)
1229 {
1230 	const struct got_error *err = NULL;
1231 	struct gotd_imsg_packfile_status istatus;
1232 	char buf[GOT_PKT_MAX];
1233 	size_t datalen, len;
1234 	char *reason = NULL;
1235 
1236 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1237 	if (datalen < sizeof(istatus))
1238 		return got_error(GOT_ERR_PRIVSEP_LEN);
1239 	memcpy(&istatus, imsg->data, sizeof(istatus));
1240 	if (datalen != sizeof(istatus) + istatus.reason_len)
1241 		return got_error(GOT_ERR_PRIVSEP_LEN);
1242 
1243 	reason = strndup(imsg->data + sizeof(istatus), istatus.reason_len);
1244 	if (reason == NULL) {
1245 		err = got_error_from_errno("strndup");
1246 		goto done;
1247 	}
1248 
1249 	if (err == NULL)
1250 		len = snprintf(buf, sizeof(buf), "unpack ok\n");
1251 	else
1252 		len = snprintf(buf, sizeof(buf), "unpack %s\n", reason);
1253 	if (len >= sizeof(buf)) {
1254 		err = got_error(GOT_ERR_NO_SPACE);
1255 		goto done;
1256 	}
1257 
1258 	err = got_pkt_writepkt(outfd, buf, len, chattygot);
1259 done:
1260 	free(reason);
1261 	return err;
1262 }
1263 
1264 static const struct got_error *
1265 recv_ref_update_ok(struct imsg *imsg, int outfd, int chattygot)
1266 {
1267 	const struct got_error *err = NULL;
1268 	struct gotd_imsg_ref_update_ok iok;
1269 	size_t datalen, len;
1270 	char buf[GOT_PKT_MAX];
1271 	char *refname = NULL;
1272 
1273 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1274 	if (datalen < sizeof(iok))
1275 		return got_error(GOT_ERR_PRIVSEP_LEN);
1276 	memcpy(&iok, imsg->data, sizeof(iok));
1277 	if (datalen != sizeof(iok) + iok.name_len)
1278 		return got_error(GOT_ERR_PRIVSEP_LEN);
1279 
1280 	memcpy(&iok, imsg->data, sizeof(iok));
1281 
1282 	refname = strndup(imsg->data + sizeof(iok), iok.name_len);
1283 	if (refname == NULL)
1284 		return got_error_from_errno("strndup");
1285 
1286 	len = snprintf(buf, sizeof(buf), "ok %s\n", refname);
1287 	if (len >= sizeof(buf)) {
1288 		err = got_error(GOT_ERR_NO_SPACE);
1289 		goto done;
1290 	}
1291 
1292 	err = got_pkt_writepkt(outfd, buf, len, chattygot);
1293 done:
1294 	free(refname);
1295 	return err;
1296 }
1297 
1298 static const struct got_error *
1299 recv_ref_update_ng(struct imsg *imsg, int outfd, int chattygot)
1300 {
1301 	const struct got_error *err = NULL;
1302 	struct gotd_imsg_ref_update_ng ing;
1303 	size_t datalen, len;
1304 	char buf[GOT_PKT_MAX];
1305 	char *refname = NULL, *reason = NULL;
1306 
1307 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1308 	if (datalen < sizeof(ing))
1309 		return got_error(GOT_ERR_PRIVSEP_LEN);
1310 	memcpy(&ing, imsg->data, sizeof(ing));
1311 	if (datalen != sizeof(ing) + ing.name_len + ing.reason_len)
1312 		return got_error(GOT_ERR_PRIVSEP_LEN);
1313 
1314 	memcpy(&ing, imsg->data, sizeof(ing));
1315 
1316 	refname = strndup(imsg->data + sizeof(ing), ing.name_len);
1317 	if (refname == NULL)
1318 		return got_error_from_errno("strndup");
1319 
1320 	reason = strndup(imsg->data + sizeof(ing) + ing.name_len,
1321 	    ing.reason_len);
1322 	if (reason == NULL) {
1323 		err = got_error_from_errno("strndup");
1324 		goto done;
1325 	}
1326 
1327 	len = snprintf(buf, sizeof(buf), "ng %s %s\n", refname, reason);
1328 	if (len >= sizeof(buf)) {
1329 		err = got_error(GOT_ERR_NO_SPACE);
1330 		goto done;
1331 	}
1332 
1333 	err = got_pkt_writepkt(outfd, buf, len, chattygot);
1334 done:
1335 	free(refname);
1336 	free(reason);
1337 	return err;
1338 }
1339 
1340 static const struct got_error *
1341 serve_write(int infd, int outfd, int gotd_sock, const char *repo_path,
1342     int chattygot)
1343 {
1344 	const struct got_error *err = NULL;
1345 	char buf[GOT_PKT_MAX];
1346 	struct imsgbuf ibuf;
1347 	enum protostate {
1348 		STATE_EXPECT_REF_UPDATE,
1349 		STATE_EXPECT_MORE_REF_UPDATES,
1350 		STATE_EXPECT_PACKFILE,
1351 		STATE_PACKFILE_RECEIVED,
1352 		STATE_REFS_UPDATED,
1353 	};
1354 	enum protostate curstate = STATE_EXPECT_REF_UPDATE;
1355 	struct imsg imsg;
1356 	int report_status = 0;
1357 
1358 	imsg_init(&ibuf, gotd_sock);
1359 	memset(&imsg, 0, sizeof(imsg));
1360 
1361 	err = announce_refs(outfd, &ibuf, 0, repo_path, chattygot);
1362 	if (err)
1363 		goto done;
1364 
1365 	while (curstate != STATE_EXPECT_PACKFILE) {
1366 		int n;
1367 		buf[0] = '\0';
1368 		err = got_pkt_readpkt(&n, infd, buf, sizeof(buf), chattygot);
1369 		if (err)
1370 			goto done;
1371 		if (n == 0) {
1372 			if (curstate != STATE_EXPECT_MORE_REF_UPDATES) {
1373 				err = got_error_msg(GOT_ERR_BAD_PACKET,
1374 				    "unexpected flush packet received");
1375 				goto done;
1376 			}
1377 			err = forward_flushpkt(&ibuf);
1378 			if (err)
1379 				goto done;
1380 			curstate = STATE_EXPECT_PACKFILE;
1381 		} else if (n >= (SHA1_DIGEST_STRING_LENGTH * 2) + 2) {
1382 			if (curstate != STATE_EXPECT_REF_UPDATE &&
1383 			    curstate != STATE_EXPECT_MORE_REF_UPDATES) {
1384 				err = got_error_msg(GOT_ERR_BAD_PACKET,
1385 				    "unexpected ref-update packet");
1386 				goto done;
1387 			}
1388 			if (curstate == STATE_EXPECT_REF_UPDATE) {
1389 				err = recv_ref_update(&report_status,
1390 				    outfd, &ibuf, buf, n, 1, chattygot);
1391 			} else {
1392 				err = recv_ref_update(NULL, outfd, &ibuf,
1393 				    buf, n, 0, chattygot);
1394 			}
1395 			if (err)
1396 				goto done;
1397 			curstate = STATE_EXPECT_MORE_REF_UPDATES;
1398 		} else {
1399 			err = got_error(GOT_ERR_BAD_PACKET);
1400 			goto done;
1401 		}
1402 	}
1403 
1404 	while (curstate != STATE_PACKFILE_RECEIVED) {
1405 		err = gotd_imsg_poll_recv(&imsg, &ibuf, 0);
1406 		if (err)
1407 			goto done;
1408 		switch (imsg.hdr.type) {
1409 		case GOTD_IMSG_ERROR:
1410 			err = gotd_imsg_recv_error(NULL, &imsg);
1411 			goto done;
1412 		case GOTD_IMSG_PACKFILE_PIPE:
1413 			err = recv_packfile(&imsg, infd);
1414 			if (err) {
1415 				if (err->code != GOT_ERR_EOF)
1416 					goto done;
1417 				/*
1418 				 * EOF is reported when the client hangs up,
1419 				 * which can happen with Git clients.
1420 				 * The socket should stay half-open so we
1421 				 * can still send our reports if requested.
1422 				 */
1423 				err = NULL;
1424 			}
1425 			curstate = STATE_PACKFILE_RECEIVED;
1426 			break;
1427 		default:
1428 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1429 			break;
1430 		}
1431 
1432 		imsg_free(&imsg);
1433 		if (err)
1434 			goto done;
1435 	}
1436 
1437 	while (curstate != STATE_REFS_UPDATED && err == NULL) {
1438 		err = gotd_imsg_poll_recv(&imsg, &ibuf, 0);
1439 		if (err)
1440 			break;
1441 		switch (imsg.hdr.type) {
1442 		case GOTD_IMSG_ERROR:
1443 			err = gotd_imsg_recv_error(NULL, &imsg);
1444 			break;
1445 		case GOTD_IMSG_PACKFILE_STATUS:
1446 			if (!report_status)
1447 				break;
1448 			err = report_unpack_status(&imsg, outfd, chattygot);
1449 			break;
1450 		case GOTD_IMSG_REF_UPDATE_OK:
1451 			if (!report_status)
1452 				break;
1453 			err = recv_ref_update_ok(&imsg, outfd, chattygot);
1454 			break;
1455 		case GOTD_IMSG_REF_UPDATE_NG:
1456 			if (!report_status)
1457 				break;
1458 			err = recv_ref_update_ng(&imsg, outfd, chattygot);
1459 			break;
1460 		case GOTD_IMSG_REFS_UPDATED:
1461 			curstate = STATE_REFS_UPDATED;
1462 			err = got_pkt_flushpkt(outfd, chattygot);
1463 			break;
1464 		default:
1465 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1466 			break;
1467 		}
1468 
1469 		imsg_free(&imsg);
1470 	}
1471 done:
1472 	imsg_clear(&ibuf);
1473 	if (err)
1474 		echo_error(err, outfd, chattygot);
1475 	return err;
1476 }
1477 
1478 const struct got_error *
1479 got_serve(int infd, int outfd, const char *command, const char *repo_path,
1480     int gotd_sock, int chattygot)
1481 {
1482 	const struct got_error *err = NULL;
1483 
1484 	if (strcmp(command, GOT_SERVE_CMD_FETCH) == 0)
1485 		err = serve_read(infd, outfd, gotd_sock, repo_path, chattygot);
1486 	else if (strcmp(command, GOT_SERVE_CMD_SEND) == 0)
1487 		err = serve_write(infd, outfd, gotd_sock, repo_path,
1488 		    chattygot);
1489 	else
1490 		err = got_error(GOT_ERR_BAD_PACKET);
1491 
1492 	return err;
1493 }