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 
40 #include "got_lib_pkt.h"
41 #include "got_lib_dial.h"
42 #include "got_lib_gitproto.h"
43 #include "got_lib_hash.h"
44 #include "got_lib_poll.h"
45 
46 #include "gotd.h"
47 
48 #ifndef nitems
49 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
50 #endif
51 
52 static const struct got_capability read_capabilities[] = {
53 	{ GOT_CAPA_AGENT, "got/" GOT_VERSION_STR },
54 	{ GOT_CAPA_OFS_DELTA, NULL },
55 	{ GOT_CAPA_SIDE_BAND_64K, NULL },
56 };
57 
58 static const struct got_capability write_capabilities[] = {
59 	{ GOT_CAPA_AGENT, "got/" GOT_VERSION_STR },
60 	{ GOT_CAPA_OFS_DELTA, NULL },
61 	{ GOT_CAPA_REPORT_STATUS, NULL },
62 	{ GOT_CAPA_NO_THIN, NULL },
63 	{ GOT_CAPA_DELETE_REFS, NULL },
64 };
65 
66 const struct got_error *
67 got_serve_parse_command(char **command, char **repo_path, const char *gitcmd)
68 {
69 	const struct got_error *err = NULL;
70 	size_t len, cmdlen, pathlen;
71 	char *path0 = NULL, *path, *abspath = NULL, *canonpath = NULL;
72 	const char *relpath;
73 
74 	*command = NULL;
75 	*repo_path = NULL;
76 
77 	len = strlen(gitcmd);
78 
79 	if (len >= strlen(GOT_SERVE_CMD_SEND) &&
80 	    strncmp(gitcmd, GOT_SERVE_CMD_SEND,
81 	    strlen(GOT_SERVE_CMD_SEND)) == 0)
82 		cmdlen = strlen(GOT_SERVE_CMD_SEND);
83 	else if (len >= strlen(GOT_SERVE_CMD_FETCH) &&
84 	    strncmp(gitcmd, GOT_SERVE_CMD_FETCH,
85 	    strlen(GOT_SERVE_CMD_FETCH)) == 0)
86 		cmdlen = strlen(GOT_SERVE_CMD_FETCH);
87 	else
88 		return got_error(GOT_ERR_BAD_PACKET);
89 
90 	if (len <= cmdlen + 1 || gitcmd[cmdlen] != ' ')
91 		return got_error(GOT_ERR_BAD_PACKET);
92 
93 	if (memchr(&gitcmd[cmdlen + 1], '\0', len - cmdlen) == NULL)
94 		return got_error(GOT_ERR_BAD_PATH);
95 
96 	/* Forbid linefeeds in paths, like Git does. */
97 	if (memchr(&gitcmd[cmdlen + 1], '\n', len - cmdlen) != NULL)
98 		return got_error(GOT_ERR_BAD_PATH);
99 
100 	path0 = strdup(&gitcmd[cmdlen + 1]);
101 	if (path0 == NULL)
102 		return got_error_from_errno("strdup");
103 	path = path0;
104 	pathlen = strlen(path);
105 
106 	/*
107 	 * Git clients send a shell command.
108 	 * Trim spaces and quotes around the path.
109 	 */
110 	while (path[0] == '\'' || path[0] == '\"' || path[0] == ' ') {
111 		path++;
112 		pathlen--;
113 	}
114 	while (pathlen > 0 &&
115 	    (path[pathlen - 1] == '\'' || path[pathlen - 1] == '\"' ||
116 	    path[pathlen - 1] == ' ')) {
117 		path[pathlen - 1] = '\0';
118 		pathlen--;
119 	}
120 
121 	/* Deny an empty repository path. */
122 	if (path[0] == '\0' || got_path_is_root_dir(path)) {
123 		err = got_error(GOT_ERR_NOT_GIT_REPO);
124 		goto done;
125 	}
126 
127 	if (asprintf(&abspath, "/%s", path) == -1) {
128 		err = got_error_from_errno("asprintf");
129 		goto done;
130 	}
131 	pathlen = strlen(abspath);
132 	canonpath = malloc(pathlen);
133 	if (canonpath == NULL) {
134 		err = got_error_from_errno("malloc");
135 		goto done;
136 	}
137 	err = got_canonpath(abspath, canonpath, pathlen);
138 	if (err)
139 		goto done;
140 
141 	relpath = canonpath;
142 	while (relpath[0] == '/')
143 		relpath++;
144 	*repo_path = strdup(relpath);
145 	if (*repo_path == NULL) {
146 		err = got_error_from_errno("strdup");
147 		goto done;
148 	}
149 	*command = strndup(gitcmd, cmdlen);
150 	if (*command == NULL)
151 		err = got_error_from_errno("strndup");
152 done:
153 	free(path0);
154 	free(abspath);
155 	free(canonpath);
156 	if (err) {
157 		free(*repo_path);
158 		*repo_path = NULL;
159 	}
160 	return err;
161 }
162 
163 static const struct got_error *
164 append_read_capabilities(size_t *capalen, size_t len, const char *symrefstr,
165     uint8_t *buf, size_t bufsize)
166 {
167 	struct got_capability capa[nitems(read_capabilities) + 1];
168 	size_t ncapa;
169 
170 	memcpy(&capa, read_capabilities, sizeof(read_capabilities));
171 	if (symrefstr) {
172 		capa[nitems(read_capabilities)].key = "symref";
173 		capa[nitems(read_capabilities)].value = symrefstr;
174 		ncapa = nitems(capa);
175 	} else
176 		ncapa = nitems(read_capabilities);
177 
178 	return got_gitproto_append_capabilities(capalen, buf, len,
179 	    bufsize, capa, ncapa);
180 }
181 
182 static const struct got_error *
183 send_ref(int outfd, uint8_t *id, const char *refname, int send_capabilities,
184     int client_is_reading, const char *symrefstr, int chattygot)
185 {
186 	const struct got_error *err = NULL;
187 	char hex[SHA1_DIGEST_STRING_LENGTH];
188 	char buf[GOT_PKT_MAX];
189 	size_t len, capalen = 0;
190 
191 	if (got_sha1_digest_to_str(id, hex, sizeof(hex)) == NULL)
192 		return got_error(GOT_ERR_BAD_OBJ_ID);
193 
194 	len = snprintf(buf, sizeof(buf), "%s %s", hex, refname);
195 	if (len >= sizeof(buf))
196 		return got_error(GOT_ERR_NO_SPACE);
197 
198 	if (send_capabilities) {
199 		if (client_is_reading) {
200 			err = append_read_capabilities(&capalen, len,
201 			    symrefstr, buf, sizeof(buf));
202 		} else {
203 			err = got_gitproto_append_capabilities(&capalen,
204 			    buf, len, sizeof(buf), write_capabilities,
205 			    nitems(write_capabilities));
206 		}
207 		if (err)
208 			return err;
209 		len += capalen;
210 	}
211 
212 	if (len + 1 >= sizeof(buf))
213 		return got_error(GOT_ERR_NO_SPACE);
214 	buf[len] = '\n';
215 	len++;
216 	buf[len] = '\0';
217 
218 	return got_pkt_writepkt(outfd, buf, len, chattygot);
219 }
220 
221 static const struct got_error *
222 send_zero_refs(int outfd, int client_is_reading, int chattygot)
223 {
224 	const struct got_error *err = NULL;
225 	const char *line = GOT_SHA1_STRING_ZERO " capabilities^{}";
226 	char buf[GOT_PKT_MAX];
227 	size_t len, capalen = 0;
228 
229 	len = strlcpy(buf, line, sizeof(buf));
230 	if (len >= sizeof(buf))
231 		return got_error(GOT_ERR_NO_SPACE);
232 
233 	if (client_is_reading) {
234 		err = got_gitproto_append_capabilities(&capalen, buf, len,
235 		    sizeof(buf), read_capabilities, nitems(read_capabilities));
236 		if (err)
237 			return err;
238 	} else {
239 		err = got_gitproto_append_capabilities(&capalen, buf, len,
240 		    sizeof(buf), write_capabilities,
241 		    nitems(write_capabilities));
242 		if (err)
243 			return err;
244 	}
245 
246 	return got_pkt_writepkt(outfd, buf, len + capalen, chattygot);
247 }
248 
249 static void
250 echo_error(const struct got_error *err, int outfd, int chattygot)
251 {
252 	char buf[4 + GOT_ERR_MAX_MSG_SIZE];
253 	size_t len;
254 
255 	/*
256 	 * Echo the error to the client on a pkt-line.
257 	 * The client should then terminate its session.
258 	 */
259 	buf[0] = 'E'; buf[1] = 'R'; buf[2] = 'R'; buf[3] = ' '; buf[4] = '\0';
260 	len = strlcat(buf, err->msg, sizeof(buf));
261 	got_pkt_writepkt(outfd, buf, len, chattygot);
262 }
263 
264 static const struct got_error *
265 announce_refs(int outfd, struct imsgbuf *ibuf, int client_is_reading,
266     const char *repo_path, int chattygot)
267 {
268 	const struct got_error *err = NULL;
269 	struct imsg imsg;
270 	size_t datalen;
271 	struct gotd_imsg_list_refs lsref;
272 	struct gotd_imsg_reflist ireflist;
273 	struct gotd_imsg_ref iref;
274 	struct gotd_imsg_symref isymref;
275 	size_t nrefs = 0;
276 	int have_nrefs = 0, sent_capabilities = 0;
277 	char *symrefname = NULL, *symreftarget = NULL, *symrefstr = NULL;
278 	char *refname = NULL;
279 
280 	memset(&imsg, 0, sizeof(imsg));
281 	memset(&lsref, 0, sizeof(lsref));
282 
283 	if (strlcpy(lsref.repo_name, repo_path, sizeof(lsref.repo_name)) >=
284 	    sizeof(lsref.repo_name))
285 		return got_error(GOT_ERR_NO_SPACE);
286 	lsref.client_is_reading = client_is_reading;
287 
288 	if (imsg_compose(ibuf, GOTD_IMSG_LIST_REFS, 0, 0, -1,
289 	    &lsref, sizeof(lsref)) == -1)
290 		return got_error_from_errno("imsg_compose LIST_REFS");
291 
292 	err = gotd_imsg_flush(ibuf);
293 	if (err)
294 		return err;
295 
296 	while (!have_nrefs || nrefs > 0) {
297 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
298 		if (err)
299 			goto done;
300 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
301 		switch (imsg.hdr.type) {
302 		case GOTD_IMSG_ERROR:
303 			err = gotd_imsg_recv_error(NULL, &imsg);
304 			goto done;
305 		case GOTD_IMSG_REFLIST:
306 			if (have_nrefs || nrefs > 0) {
307 				err = got_error(GOT_ERR_PRIVSEP_MSG);
308 				goto done;
309 			}
310 			if (datalen != sizeof(ireflist)) {
311 				err = got_error(GOT_ERR_PRIVSEP_MSG);
312 				goto done;
313 			}
314 			memcpy(&ireflist, imsg.data, sizeof(ireflist));
315 			nrefs = ireflist.nrefs;
316 			have_nrefs = 1;
317 			if (nrefs == 0)
318 				err = send_zero_refs(outfd, client_is_reading,
319 				    chattygot);
320 			break;
321 		case GOTD_IMSG_REF:
322 			if (!have_nrefs || nrefs == 0) {
323 				err = got_error(GOT_ERR_PRIVSEP_MSG);
324 				goto done;
325 			}
326 			if (datalen < sizeof(iref)) {
327 				err = got_error(GOT_ERR_PRIVSEP_MSG);
328 				goto done;
329 			}
330 			memcpy(&iref, imsg.data, sizeof(iref));
331 			if (datalen != sizeof(iref) + iref.name_len) {
332 				err = got_error(GOT_ERR_PRIVSEP_LEN);
333 				goto done;
334 			}
335 			refname = strndup(imsg.data + sizeof(iref),
336 			    iref.name_len);
337 			if (refname == NULL) {
338 				err = got_error_from_errno("strndup");
339 				goto done;
340 			}
341 			err = send_ref(outfd, iref.id, refname,
342 			    !sent_capabilities, client_is_reading,
343 			    NULL, chattygot);
344 			free(refname);
345 			refname = NULL;
346 			if (err)
347 				goto done;
348 			sent_capabilities = 1;
349 			if (nrefs > 0)
350 				nrefs--;
351 			break;
352 		case GOTD_IMSG_SYMREF:
353 			if (!have_nrefs || nrefs == 0) {
354 				err = got_error(GOT_ERR_PRIVSEP_MSG);
355 				goto done;
356 			}
357 			if (datalen < sizeof(isymref)) {
358 				err = got_error(GOT_ERR_PRIVSEP_LEN);
359 				goto done;
360 			}
361 			memcpy(&isymref, imsg.data, sizeof(isymref));
362 			if (datalen != sizeof(isymref) + isymref.name_len +
363 			    isymref.target_len) {
364 				err = got_error(GOT_ERR_PRIVSEP_LEN);
365 				goto done;
366 			}
367 
368 			/*
369 			 * For now, we only announce one symbolic ref,
370 			 * as part of our capability advertisement.
371 			 */
372 			if (sent_capabilities || symrefstr != NULL ||
373 			    symrefname != NULL || symreftarget != NULL)
374 				break;
375 
376 			symrefname = strndup(imsg.data + sizeof(isymref),
377 			    isymref.name_len);
378 			if (symrefname == NULL) {
379 				err = got_error_from_errno("malloc");
380 				goto done;
381 			}
382 
383 			symreftarget = strndup(
384 			    imsg.data + sizeof(isymref) + isymref.name_len,
385 			    isymref.target_len);
386 			if (symreftarget == NULL) {
387 				err = got_error_from_errno("strndup");
388 				goto done;
389 			}
390 
391 			if (asprintf(&symrefstr, "%s:%s", symrefname,
392 			    symreftarget) == -1) {
393 				err = got_error_from_errno("asprintf");
394 				goto done;
395 			}
396 			err = send_ref(outfd, isymref.target_id, symrefname,
397 			    !sent_capabilities, client_is_reading, symrefstr,
398 			    chattygot);
399 			free(refname);
400 			refname = NULL;
401 			if (err)
402 				goto done;
403 			sent_capabilities = 1;
404 			if (nrefs > 0)
405 				nrefs--;
406 			break;
407 		default:
408 			err = got_error(GOT_ERR_PRIVSEP_MSG);
409 			break;
410 		}
411 
412 		imsg_free(&imsg);
413 	}
414 
415 	err = got_pkt_flushpkt(outfd, chattygot);
416 	if (err)
417 		goto done;
418 done:
419 	free(symrefstr);
420 	free(symrefname);
421 	free(symreftarget);
422 	return err;
423 }
424 
425 static const struct got_error *
426 parse_want_line(char **common_capabilities, uint8_t *id, char *buf, size_t len)
427 {
428 	const struct got_error *err;
429 	char *id_str = NULL, *client_capabilities = NULL;
430 
431 	err = got_gitproto_parse_want_line(&id_str,
432 	    &client_capabilities, buf, len);
433 	if (err)
434 		return err;
435 
436 	if (!got_parse_sha1_digest(id, id_str)) {
437 		err = got_error_msg(GOT_ERR_BAD_PACKET,
438 		    "want-line with bad object ID");
439 		goto done;
440 	}
441 
442 	if (client_capabilities) {
443 		err = got_gitproto_match_capabilities(common_capabilities,
444 		    NULL, client_capabilities, read_capabilities,
445 		    nitems(read_capabilities));
446 		if (err)
447 			goto done;
448 	}
449 done:
450 	free(id_str);
451 	free(client_capabilities);
452 	return err;
453 }
454 
455 static const struct got_error *
456 parse_have_line(uint8_t *id, char *buf, size_t len)
457 {
458 	const struct got_error *err;
459 	char *id_str = NULL;
460 
461 	err = got_gitproto_parse_have_line(&id_str, buf, len);
462 	if (err)
463 		return err;
464 
465 	if (!got_parse_sha1_digest(id, id_str)) {
466 		err = got_error_msg(GOT_ERR_BAD_PACKET,
467 		    "have-line with bad object ID");
468 		goto done;
469 	}
470 done:
471 	free(id_str);
472 	return err;
473 }
474 
475 static const struct got_error *
476 send_capability(struct got_capability *capa, struct imsgbuf *ibuf)
477 {
478 	const struct got_error *err = NULL;
479 	struct gotd_imsg_capability icapa;
480 	size_t len;
481 	struct ibuf *wbuf;
482 
483 	memset(&icapa, 0, sizeof(icapa));
484 
485 	icapa.key_len = strlen(capa->key);
486 	len = sizeof(icapa) + icapa.key_len;
487 	if (capa->value) {
488 		icapa.value_len = strlen(capa->value);
489 		len += icapa.value_len;
490 	}
491 
492 	wbuf = imsg_create(ibuf, GOTD_IMSG_CAPABILITY, 0, 0, len);
493 	if (wbuf == NULL) {
494 		err = got_error_from_errno("imsg_create CAPABILITY");
495 		return err;
496 	}
497 
498 	if (imsg_add(wbuf, &icapa, sizeof(icapa)) == -1)
499 		return got_error_from_errno("imsg_add CAPABILITY");
500 	if (imsg_add(wbuf, capa->key, icapa.key_len) == -1)
501 		return got_error_from_errno("imsg_add CAPABILITY");
502 	if (capa->value) {
503 		if (imsg_add(wbuf, capa->value, icapa.value_len) == -1)
504 			return got_error_from_errno("imsg_add CAPABILITY");
505 	}
506 
507 	wbuf->fd = -1;
508 	imsg_close(ibuf, wbuf);
509 
510 	return NULL;
511 }
512 
513 static const struct got_error *
514 send_capabilities(int *use_sidebands, int *report_status,
515     char *capabilities_str, struct imsgbuf *ibuf)
516 {
517 	const struct got_error *err = NULL;
518 	struct gotd_imsg_capabilities icapas;
519 	struct got_capability *capa = NULL;
520 	size_t ncapa, i;
521 
522 	err = got_gitproto_split_capabilities_str(&capa, &ncapa,
523 	    capabilities_str);
524 	if (err)
525 		return err;
526 
527 	icapas.ncapabilities = ncapa;
528 	if (imsg_compose(ibuf, GOTD_IMSG_CAPABILITIES, 0, 0, -1,
529 	    &icapas, sizeof(icapas)) == -1) {
530 		err = got_error_from_errno("imsg_compose IMSG_CAPABILITIES");
531 		goto done;
532 	}
533 
534 	for (i = 0; i < ncapa; i++) {
535 		err = send_capability(&capa[i], ibuf);
536 		if (err)
537 			goto done;
538 		if (use_sidebands &&
539 		    strcmp(capa[i].key, GOT_CAPA_SIDE_BAND_64K) == 0)
540 			*use_sidebands = 1;
541 		if (report_status &&
542 		    strcmp(capa[i].key, GOT_CAPA_REPORT_STATUS) == 0)
543 			*report_status = 1;
544 	}
545 done:
546 	free(capa);
547 	return err;
548 }
549 
550 static const struct got_error *
551 forward_flushpkt(struct imsgbuf *ibuf)
552 {
553 	if (imsg_compose(ibuf, GOTD_IMSG_FLUSH, 0, 0, -1, NULL, 0) == -1)
554 		return got_error_from_errno("imsg_compose FLUSH");
555 
556 	return gotd_imsg_flush(ibuf);
557 }
558 
559 static const struct got_error *
560 recv_ack(struct imsg *imsg, uint8_t *expected_id)
561 {
562 	struct gotd_imsg_ack iack;
563 	size_t datalen;
564 
565 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
566 	if (datalen != sizeof(iack))
567 		return got_error(GOT_ERR_PRIVSEP_LEN);
568 
569 	memcpy(&iack, imsg->data, sizeof(iack));
570 	if (memcmp(iack.object_id, expected_id, SHA1_DIGEST_LENGTH) != 0)
571 		return got_error(GOT_ERR_BAD_OBJ_ID);
572 
573 	return NULL;
574 }
575 
576 static const struct got_error *
577 recv_nak(struct imsg *imsg, uint8_t *expected_id)
578 {
579 	struct gotd_imsg_ack inak;
580 	size_t datalen;
581 
582 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
583 	if (datalen != sizeof(inak))
584 		return got_error(GOT_ERR_PRIVSEP_LEN);
585 
586 	memcpy(&inak, imsg->data, sizeof(inak));
587 	if (memcmp(inak.object_id, expected_id, SHA1_DIGEST_LENGTH) != 0)
588 		return got_error(GOT_ERR_BAD_OBJ_ID);
589 
590 	return NULL;
591 }
592 
593 
594 static const struct got_error *
595 recv_want(int *use_sidebands, int outfd, struct imsgbuf *ibuf,
596     char *buf, size_t len, int expect_capabilities, int chattygot)
597 {
598 	const struct got_error *err;
599 	struct gotd_imsg_want iwant;
600 	char *capabilities_str;
601 	int done = 0;
602 	struct imsg imsg;
603 
604 	memset(&iwant, 0, sizeof(iwant));
605 	memset(&imsg, 0, sizeof(imsg));
606 
607 	err = parse_want_line(&capabilities_str, iwant.object_id, buf, len);
608 	if (err)
609 		return err;
610 
611 	if (capabilities_str) {
612 		if (!expect_capabilities) {
613 			err = got_error_msg(GOT_ERR_BAD_PACKET,
614 			    "unexpected capability announcement received");
615 			goto done;
616 		}
617 		err = send_capabilities(use_sidebands, NULL, capabilities_str,
618 		    ibuf);
619 		if (err)
620 			goto done;
621 
622 	}
623 
624 	if (imsg_compose(ibuf, GOTD_IMSG_WANT, 0, 0, -1,
625 	    &iwant, sizeof(iwant)) == -1) {
626 		err = got_error_from_errno("imsg_compose WANT");
627 		goto done;
628 	}
629 
630 	err = gotd_imsg_flush(ibuf);
631 	if (err)
632 		goto done;
633 
634 	/*
635 	 * Wait for an ACK, or an error in case the desired object
636 	 * does not exist.
637 	 */
638 	while (!done && err == NULL) {
639 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
640 		if (err)
641 			break;
642 		switch (imsg.hdr.type) {
643 		case GOTD_IMSG_ERROR:
644 			err = gotd_imsg_recv_error(NULL, &imsg);
645 			break;
646 		case GOTD_IMSG_ACK:
647 			err = recv_ack(&imsg, iwant.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 done:
660 	free(capabilities_str);
661 	return err;
662 }
663 
664 static const struct got_error *
665 send_ack(int outfd, uint8_t *id, int chattygot)
666 {
667 	char hex[SHA1_DIGEST_STRING_LENGTH];
668 	char buf[GOT_PKT_MAX];
669 	int len;
670 
671 	if (got_sha1_digest_to_str(id, hex, sizeof(hex)) == NULL)
672 		return got_error(GOT_ERR_BAD_OBJ_ID);
673 
674 	len = snprintf(buf, sizeof(buf), "ACK %s\n", hex);
675 	if (len >= sizeof(buf))
676 		return got_error(GOT_ERR_NO_SPACE);
677 
678 	return got_pkt_writepkt(outfd, buf, len, chattygot);
679 }
680 
681 static const struct got_error *
682 send_nak(int outfd, int chattygot)
683 {
684 	char buf[5];
685 	int len;
686 
687 	len = snprintf(buf, sizeof(buf), "NAK\n");
688 	if (len >= sizeof(buf))
689 		return got_error(GOT_ERR_NO_SPACE);
690 
691 	return got_pkt_writepkt(outfd, buf, len, chattygot);
692 }
693 
694 static const struct got_error *
695 recv_have(int *have_ack, int outfd, struct imsgbuf *ibuf, char *buf,
696     size_t len, int chattygot)
697 {
698 	const struct got_error *err;
699 	struct gotd_imsg_have ihave;
700 	int done = 0;
701 	struct imsg imsg;
702 
703 	memset(&ihave, 0, sizeof(ihave));
704 	memset(&imsg, 0, sizeof(imsg));
705 
706 	err = parse_have_line(ihave.object_id, buf, len);
707 	if (err)
708 		return err;
709 
710 	if (imsg_compose(ibuf, GOTD_IMSG_HAVE, 0, 0, -1,
711 	    &ihave, sizeof(ihave)) == -1)
712 		return got_error_from_errno("imsg_compose HAVE");
713 
714 	err = gotd_imsg_flush(ibuf);
715 	if (err)
716 		return err;
717 
718 	/*
719 	 * Wait for an ACK or a NAK, indicating whether a common
720 	 * commit object has been found.
721 	 */
722 	while (!done && err == NULL) {
723 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
724 		if (err)
725 			return err;
726 		switch (imsg.hdr.type) {
727 		case GOTD_IMSG_ERROR:
728 			err = gotd_imsg_recv_error(NULL, &imsg);
729 			break;
730 		case GOTD_IMSG_ACK:
731 			err = recv_ack(&imsg, ihave.object_id);
732 			if (err)
733 				break;
734 			if (!*have_ack) {
735 				err = send_ack(outfd, ihave.object_id,
736 				    chattygot);
737 				if (err)
738 					return err;
739 				*have_ack = 1;
740 			}
741 			done = 1;
742 			break;
743 		case GOTD_IMSG_NAK:
744 			err = recv_nak(&imsg, ihave.object_id);
745 			if (err)
746 				break;
747 			done = 1;
748 			break;
749 		default:
750 			err = got_error(GOT_ERR_PRIVSEP_MSG);
751 			break;
752 		}
753 
754 		imsg_free(&imsg);
755 	}
756 
757 	return err;
758 }
759 
760 static const struct got_error *
761 recv_done(int *packfd, int outfd, struct imsgbuf *ibuf, int chattygot)
762 {
763 	const struct got_error *err;
764 	struct imsg imsg;
765 
766 	*packfd = -1;
767 
768 	if (imsg_compose(ibuf, GOTD_IMSG_DONE, 0, 0, -1, NULL, 0) == -1)
769 		return got_error_from_errno("imsg_compose DONE");
770 
771 	err = gotd_imsg_flush(ibuf);
772 	if (err)
773 		return err;
774 
775 	while (*packfd == -1 && err == NULL) {
776 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
777 		if (err)
778 			break;
779 
780 		switch (imsg.hdr.type) {
781 		case GOTD_IMSG_ERROR:
782 			err = gotd_imsg_recv_error(NULL, &imsg);
783 			break;
784 		case GOTD_IMSG_PACKFILE_PIPE:
785 			if (imsg.fd != -1)
786 				*packfd = imsg.fd;
787 			else
788 				err = got_error(GOT_ERR_PRIVSEP_NO_FD);
789 			break;
790 		default:
791 			err = got_error(GOT_ERR_PRIVSEP_MSG);
792 			break;
793 		}
794 
795 		imsg_free(&imsg);
796 	}
797 
798 	return err;
799 }
800 
801 static const struct got_error *
802 relay_progress_reports(struct imsgbuf *ibuf, int outfd, int chattygot)
803 {
804 	const struct got_error *err = NULL;
805 	int pack_starting = 0;
806 	struct gotd_imsg_packfile_progress iprog;
807 	char buf[GOT_PKT_MAX];
808 	struct imsg imsg;
809 	size_t datalen;
810 	int p_deltify = 0, n;
811 	const char *eol = "\r";
812 
813 	memset(&imsg, 0, sizeof(imsg));
814 
815 	while (!pack_starting && err == NULL) {
816 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
817 		if (err)
818 			break;
819 
820 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
821 		switch (imsg.hdr.type) {
822 		case GOTD_IMSG_ERROR:
823 			err = gotd_imsg_recv_error(NULL, &imsg);
824 			break;
825 		case GOTD_IMSG_PACKFILE_READY:
826 			eol = "\n";
827 			pack_starting = 1;
828 			/* fallthrough */
829 		case GOTD_IMSG_PACKFILE_PROGRESS:
830 			if (datalen != sizeof(iprog)) {
831 				err = got_error(GOT_ERR_PRIVSEP_LEN);
832 				break;
833 			}
834 			memcpy(&iprog, imsg.data, sizeof(iprog));
835 			if (iprog.nobj_total > 0) {
836 				p_deltify = (iprog.nobj_deltify * 100) /
837 				    iprog.nobj_total;
838 			}
839 			buf[0] = GOT_SIDEBAND_PROGRESS_INFO;
840 			n = snprintf(&buf[1], sizeof(buf) - 1,
841 			    "%d commits colored, "
842 			    "%d objects found, "
843 			    "deltify %d%%%s",
844 			    iprog.ncolored,
845 			    iprog.nfound,
846 			    p_deltify, eol);
847 			if (n >= sizeof(buf) - 1)
848 				break;
849 			err = got_pkt_writepkt(outfd, buf, 1 + n, chattygot);
850 			break;
851 		default:
852 			err = got_error(GOT_ERR_PRIVSEP_MSG);
853 			break;
854 		}
855 
856 		imsg_free(&imsg);
857 	}
858 
859 	return err;
860 }
861 
862 static const struct got_error *
863 serve_read(int infd, int outfd, int gotd_sock, const char *repo_path,
864     int chattygot)
865 {
866 	const struct got_error *err = NULL;
867 	char buf[GOT_PKT_MAX];
868 	struct imsgbuf ibuf;
869 	enum protostate {
870 		STATE_EXPECT_WANT,
871 		STATE_EXPECT_MORE_WANT,
872 		STATE_EXPECT_HAVE,
873 		STATE_EXPECT_DONE,
874 		STATE_DONE,
875 	};
876 	enum protostate curstate = STATE_EXPECT_WANT;
877 	int have_ack = 0, use_sidebands = 0, seen_have = 0;
878 	int packfd = -1;
879 	size_t pack_chunksize;
880 
881 	imsg_init(&ibuf, gotd_sock);
882 
883 	err = announce_refs(outfd, &ibuf, 1, repo_path, chattygot);
884 	if (err)
885 		goto done;
886 
887 	while (curstate != STATE_DONE) {
888 		int n;
889 		buf[0] = '\0';
890 		err = got_pkt_readpkt(&n, infd, buf, sizeof(buf), chattygot);
891 		if (err)
892 			goto done;
893 		if (n == 0) {
894 			if (curstate != STATE_EXPECT_WANT &&
895 			    curstate != STATE_EXPECT_MORE_WANT &&
896 			    curstate != STATE_EXPECT_HAVE &&
897 			    curstate != STATE_EXPECT_DONE) {
898 				err = got_error_msg(GOT_ERR_BAD_PACKET,
899 				    "unexpected flush packet received");
900 				goto done;
901 			}
902 
903 			if (curstate == STATE_EXPECT_WANT) {
904 				ssize_t r;
905 				/*
906 				 * If the client does not want to fetch
907 				 * anything we should receive a flush
908 				 * packet followed by EOF.
909 				 */
910 				r = read(infd, buf, sizeof(buf));
911 				if (r == -1) {
912 					err = got_error_from_errno("read");
913 					goto done;
914 				}
915 				if (r == 0) /* EOF */
916 					goto done;
917 
918 				/* Zero-length field followed by payload. */
919 				err = got_error_msg(GOT_ERR_BAD_PACKET,
920 				    "unexpected flush packet received");
921 				goto done;
922 			}
923 
924 			if (curstate == STATE_EXPECT_WANT ||
925 			    curstate == STATE_EXPECT_MORE_WANT ||
926 			    curstate == STATE_EXPECT_HAVE) {
927 				err = forward_flushpkt(&ibuf);
928 				if (err)
929 					goto done;
930 			}
931 			if (curstate == STATE_EXPECT_HAVE && !have_ack) {
932 				err = send_nak(outfd, chattygot);
933 				if (err)
934 					goto done;
935 			}
936 			if (curstate == STATE_EXPECT_MORE_WANT)
937 				curstate = STATE_EXPECT_HAVE;
938 			else
939 				curstate = STATE_EXPECT_DONE;
940 		} else if (n >= 5 && strncmp(buf, "want ", 5) == 0) {
941 			if (curstate != STATE_EXPECT_WANT &&
942 			    curstate != STATE_EXPECT_MORE_WANT) {
943 				err = got_error_msg(GOT_ERR_BAD_PACKET,
944 				    "unexpected 'want' packet");
945 				goto done;
946 			}
947 			err = recv_want(&use_sidebands, outfd, &ibuf, buf, n,
948 			    curstate == STATE_EXPECT_WANT ? 1 : 0, chattygot);
949 			if (err)
950 				goto done;
951 			if (curstate == STATE_EXPECT_WANT)
952 				curstate = STATE_EXPECT_MORE_WANT;
953 		} else if (n >= 5 && strncmp(buf, "have ", 5) == 0) {
954 			if (curstate != STATE_EXPECT_HAVE &&
955 			    curstate != STATE_EXPECT_DONE) {
956 				err = got_error_msg(GOT_ERR_BAD_PACKET,
957 				    "unexpected 'have' packet");
958 				goto done;
959 			}
960 			if (curstate == STATE_EXPECT_HAVE) {
961 				err = recv_have(&have_ack, outfd, &ibuf,
962 				    buf, n, chattygot);
963 				if (err)
964 					goto done;
965 				seen_have = 1;
966 				if (have_ack)
967 					curstate = STATE_EXPECT_DONE;
968 			}
969 		} else if (n == 5 && strncmp(buf, "done\n", 5) == 0) {
970 			if (curstate != STATE_EXPECT_HAVE &&
971 			    curstate != STATE_EXPECT_DONE) {
972 				err = got_error_msg(GOT_ERR_BAD_PACKET,
973 				    "unexpected 'done' packet");
974 				goto done;
975 			}
976 			err = recv_done(&packfd, outfd, &ibuf, chattygot);
977 			if (err)
978 				goto done;
979 			curstate = STATE_DONE;
980 			break;
981 		} else {
982 			err = got_error(GOT_ERR_BAD_PACKET);
983 			goto done;
984 		}
985 	}
986 
987 	if (!seen_have) {
988 		err = send_nak(outfd, chattygot);
989 		if (err)
990 			goto done;
991 	}
992 
993 	if (use_sidebands) {
994 		err = relay_progress_reports(&ibuf, outfd, chattygot);
995 		if (err)
996 			goto done;
997 		pack_chunksize = GOT_SIDEBAND_64K_PACKFILE_DATA_MAX;
998 	} else
999 		pack_chunksize = sizeof(buf);
1000 
1001 	for (;;) {
1002 		ssize_t r;
1003 
1004 		r = read(packfd, use_sidebands ? &buf[1] : buf,
1005 		    pack_chunksize);
1006 		if (r == -1) {
1007 			err = got_error_from_errno("read");
1008 			break;
1009 		} else if (r == 0) {
1010 			err = got_pkt_flushpkt(outfd, chattygot);
1011 			break;
1012 		}
1013 
1014 		if (use_sidebands) {
1015 			buf[0] = GOT_SIDEBAND_PACKFILE_DATA;
1016 			err = got_pkt_writepkt(outfd, buf, 1 + r, chattygot);
1017 			if (err)
1018 				break;
1019 		} else {
1020 			err = got_poll_write_full(outfd, buf, r);
1021 			if (err) {
1022 				if (err->code == GOT_ERR_EOF)
1023 					err = NULL;
1024 				break;
1025 			}
1026 		}
1027 	}
1028 done:
1029 	imsg_clear(&ibuf);
1030 	if (packfd != -1 && close(packfd) == -1 && err == NULL)
1031 		err = got_error_from_errno("close");
1032 	if (err)
1033 		echo_error(err, outfd, chattygot);
1034 	return err;
1035 }
1036 
1037 static const struct got_error *
1038 parse_ref_update_line(char **common_capabilities, char **refname,
1039     uint8_t *old_id, uint8_t *new_id, char *buf, size_t len)
1040 {
1041 	const struct got_error *err;
1042 	char *old_id_str = NULL, *new_id_str = NULL;
1043 	char *client_capabilities = NULL;
1044 
1045 	*refname = NULL;
1046 
1047 	err = got_gitproto_parse_ref_update_line(&old_id_str, &new_id_str,
1048 	    refname, &client_capabilities, buf, len);
1049 	if (err)
1050 		return err;
1051 
1052 	if (!got_parse_sha1_digest(old_id, old_id_str) ||
1053 	    !got_parse_sha1_digest(new_id, new_id_str)) {
1054 		err = got_error_msg(GOT_ERR_BAD_PACKET,
1055 		    "ref-update with bad object ID");
1056 		goto done;
1057 	}
1058 	if (!got_ref_name_is_valid(*refname)) {
1059 		err = got_error_msg(GOT_ERR_BAD_PACKET,
1060 		    "ref-update with bad reference name");
1061 		goto done;
1062 	}
1063 
1064 	if (client_capabilities) {
1065 		err = got_gitproto_match_capabilities(common_capabilities,
1066 		    NULL, client_capabilities, write_capabilities,
1067 		    nitems(write_capabilities));
1068 		if (err)
1069 			goto done;
1070 	}
1071 done:
1072 	free(old_id_str);
1073 	free(new_id_str);
1074 	free(client_capabilities);
1075 	if (err) {
1076 		free(*refname);
1077 		*refname = NULL;
1078 	}
1079 	return err;
1080 }
1081 
1082 static const struct got_error *
1083 recv_ref_update(int *report_status, int outfd, struct imsgbuf *ibuf,
1084     char *buf, size_t len, int expect_capabilities, int chattygot)
1085 {
1086 	const struct got_error *err;
1087 	struct gotd_imsg_ref_update iref;
1088 	struct ibuf *wbuf;
1089 	char *capabilities_str = NULL, *refname = NULL;
1090 	int done = 0;
1091 	struct imsg imsg;
1092 
1093 	memset(&iref, 0, sizeof(iref));
1094 	memset(&imsg, 0, sizeof(imsg));
1095 
1096 	err = parse_ref_update_line(&capabilities_str, &refname,
1097 	    iref.old_id, iref.new_id, buf, len);
1098 	if (err)
1099 		return err;
1100 
1101 	if (capabilities_str) {
1102 		if (!expect_capabilities) {
1103 			err = got_error_msg(GOT_ERR_BAD_PACKET,
1104 			    "unexpected capability announcement received");
1105 			goto done;
1106 		}
1107 		err = send_capabilities(NULL, report_status, capabilities_str,
1108 		    ibuf);
1109 		if (err)
1110 			goto done;
1111 	}
1112 
1113 	iref.name_len = strlen(refname);
1114 	len = sizeof(iref) + iref.name_len;
1115 	wbuf = imsg_create(ibuf, GOTD_IMSG_REF_UPDATE, 0, 0, len);
1116 	if (wbuf == NULL) {
1117 		err = got_error_from_errno("imsg_create REF_UPDATE");
1118 		goto done;
1119 	}
1120 
1121 	if (imsg_add(wbuf, &iref, sizeof(iref)) == -1)
1122 		return got_error_from_errno("imsg_add REF_UPDATE");
1123 	if (imsg_add(wbuf, refname, iref.name_len) == -1)
1124 		return got_error_from_errno("imsg_add REF_UPDATE");
1125 	wbuf->fd = -1;
1126 	imsg_close(ibuf, wbuf);
1127 
1128 	err = gotd_imsg_flush(ibuf);
1129 	if (err)
1130 		goto done;
1131 
1132 	/* Wait for ACK or an error. */
1133 	while (!done && err == NULL) {
1134 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
1135 		if (err)
1136 			break;
1137 		switch (imsg.hdr.type) {
1138 		case GOTD_IMSG_ERROR:
1139 			err = gotd_imsg_recv_error(NULL, &imsg);
1140 			break;
1141 		case GOTD_IMSG_ACK:
1142 			err = recv_ack(&imsg, iref.new_id);
1143 			if (err)
1144 				break;
1145 			done = 1;
1146 			break;
1147 		default:
1148 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1149 			break;
1150 		}
1151 
1152 		imsg_free(&imsg);
1153 	}
1154 done:
1155 	free(capabilities_str);
1156 	free(refname);
1157 	return err;
1158 }
1159 
1160 static const struct got_error *
1161 recv_packfile(struct imsg *imsg, int infd)
1162 {
1163 	const struct got_error *err = NULL;
1164 	size_t datalen;
1165 	int packfd;
1166 	char buf[GOT_PKT_MAX];
1167 	int pack_done = 0;
1168 
1169 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1170 	if (datalen != 0)
1171 		return got_error(GOT_ERR_PRIVSEP_MSG);
1172 
1173 	if (imsg->fd == -1)
1174 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
1175 
1176 	packfd = imsg->fd;
1177 	while (!pack_done) {
1178 		ssize_t r = 0;
1179 
1180 		err = got_poll_fd(infd, POLLIN, 1);
1181 		if (err) {
1182 			if (err->code != GOT_ERR_TIMEOUT)
1183 				break;
1184 			err = NULL;
1185 		} else {
1186 			r = read(infd, buf, sizeof(buf));
1187 			if (r == -1) {
1188 				err = got_error_from_errno("read");
1189 				break;
1190 			}
1191 			if (r == 0) {
1192 				/*
1193 				 * Git clients hang up their side of the
1194 				 * connection after sending the pack file.
1195 				 */
1196 				err = NULL;
1197 				pack_done = 1;
1198 				break;
1199 			}
1200 		}
1201 
1202 		if (r == 0) {
1203 			/* Detect gotd(8) closing the pack pipe when done. */
1204 			err = got_poll_fd(packfd, POLLOUT, 1);
1205 			if (err) {
1206 				if (err->code != GOT_ERR_EOF)
1207 					break;
1208 				err = NULL;
1209 				pack_done = 1;
1210 			}
1211 		} else {
1212 			/* Write pack data and/or detect pipe being closed. */
1213 			err = got_poll_write_full(packfd, buf, r);
1214 			if (err) {
1215 				if (err->code == GOT_ERR_EOF)
1216 					err = NULL;
1217 				break;
1218 			}
1219 		}
1220 	}
1221 
1222 	close(packfd);
1223 	return err;
1224 }
1225 
1226 static const struct got_error *
1227 report_unpack_status(struct imsg *imsg, int outfd, int chattygot)
1228 {
1229 	const struct got_error *err = NULL;
1230 	struct gotd_imsg_packfile_status istatus;
1231 	char buf[GOT_PKT_MAX];
1232 	size_t datalen, len;
1233 	char *reason = NULL;
1234 
1235 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1236 	if (datalen < sizeof(istatus))
1237 		return got_error(GOT_ERR_PRIVSEP_LEN);
1238 	memcpy(&istatus, imsg->data, sizeof(istatus));
1239 	if (datalen != sizeof(istatus) + istatus.reason_len)
1240 		return got_error(GOT_ERR_PRIVSEP_LEN);
1241 
1242 	reason = strndup(imsg->data + sizeof(istatus), istatus.reason_len);
1243 	if (reason == NULL) {
1244 		err = got_error_from_errno("strndup");
1245 		goto done;
1246 	}
1247 
1248 	if (err == NULL)
1249 		len = snprintf(buf, sizeof(buf), "unpack ok\n");
1250 	else
1251 		len = snprintf(buf, sizeof(buf), "unpack %s\n", reason);
1252 	if (len >= sizeof(buf)) {
1253 		err = got_error(GOT_ERR_NO_SPACE);
1254 		goto done;
1255 	}
1256 
1257 	err = got_pkt_writepkt(outfd, buf, len, chattygot);
1258 done:
1259 	free(reason);
1260 	return err;
1261 }
1262 
1263 static const struct got_error *
1264 recv_ref_update_ok(struct imsg *imsg, int outfd, int chattygot)
1265 {
1266 	const struct got_error *err = NULL;
1267 	struct gotd_imsg_ref_update_ok iok;
1268 	size_t datalen, len;
1269 	char buf[GOT_PKT_MAX];
1270 	char *refname = NULL;
1271 
1272 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1273 	if (datalen < sizeof(iok))
1274 		return got_error(GOT_ERR_PRIVSEP_LEN);
1275 	memcpy(&iok, imsg->data, sizeof(iok));
1276 	if (datalen != sizeof(iok) + iok.name_len)
1277 		return got_error(GOT_ERR_PRIVSEP_LEN);
1278 
1279 	memcpy(&iok, imsg->data, sizeof(iok));
1280 
1281 	refname = strndup(imsg->data + sizeof(iok), iok.name_len);
1282 	if (refname == NULL)
1283 		return got_error_from_errno("strndup");
1284 
1285 	len = snprintf(buf, sizeof(buf), "ok %s\n", refname);
1286 	if (len >= sizeof(buf)) {
1287 		err = got_error(GOT_ERR_NO_SPACE);
1288 		goto done;
1289 	}
1290 
1291 	err = got_pkt_writepkt(outfd, buf, len, chattygot);
1292 done:
1293 	free(refname);
1294 	return err;
1295 }
1296 
1297 static const struct got_error *
1298 recv_ref_update_ng(struct imsg *imsg, int outfd, int chattygot)
1299 {
1300 	const struct got_error *err = NULL;
1301 	struct gotd_imsg_ref_update_ng ing;
1302 	size_t datalen, len;
1303 	char buf[GOT_PKT_MAX];
1304 	char *refname = NULL, *reason = NULL;
1305 
1306 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1307 	if (datalen < sizeof(ing))
1308 		return got_error(GOT_ERR_PRIVSEP_LEN);
1309 	memcpy(&ing, imsg->data, sizeof(ing));
1310 	if (datalen != sizeof(ing) + ing.name_len + ing.reason_len)
1311 		return got_error(GOT_ERR_PRIVSEP_LEN);
1312 
1313 	memcpy(&ing, imsg->data, sizeof(ing));
1314 
1315 	refname = strndup(imsg->data + sizeof(ing), ing.name_len);
1316 	if (refname == NULL)
1317 		return got_error_from_errno("strndup");
1318 
1319 	reason = strndup(imsg->data + sizeof(ing) + ing.name_len,
1320 	    ing.reason_len);
1321 	if (reason == NULL) {
1322 		err = got_error_from_errno("strndup");
1323 		goto done;
1324 	}
1325 
1326 	len = snprintf(buf, sizeof(buf), "ng %s %s\n", refname, reason);
1327 	if (len >= sizeof(buf)) {
1328 		err = got_error(GOT_ERR_NO_SPACE);
1329 		goto done;
1330 	}
1331 
1332 	err = got_pkt_writepkt(outfd, buf, len, chattygot);
1333 done:
1334 	free(refname);
1335 	free(reason);
1336 	return err;
1337 }
1338 
1339 static const struct got_error *
1340 serve_write(int infd, int outfd, int gotd_sock, const char *repo_path,
1341     int chattygot)
1342 {
1343 	const struct got_error *err = NULL;
1344 	char buf[GOT_PKT_MAX];
1345 	struct imsgbuf ibuf;
1346 	enum protostate {
1347 		STATE_EXPECT_REF_UPDATE,
1348 		STATE_EXPECT_MORE_REF_UPDATES,
1349 		STATE_EXPECT_PACKFILE,
1350 		STATE_PACKFILE_RECEIVED,
1351 		STATE_REFS_UPDATED,
1352 	};
1353 	enum protostate curstate = STATE_EXPECT_REF_UPDATE;
1354 	struct imsg imsg;
1355 	int report_status = 0;
1356 
1357 	imsg_init(&ibuf, gotd_sock);
1358 	memset(&imsg, 0, sizeof(imsg));
1359 
1360 	err = announce_refs(outfd, &ibuf, 0, repo_path, chattygot);
1361 	if (err)
1362 		goto done;
1363 
1364 	while (curstate != STATE_EXPECT_PACKFILE) {
1365 		int n;
1366 		buf[0] = '\0';
1367 		err = got_pkt_readpkt(&n, infd, buf, sizeof(buf), chattygot);
1368 		if (err)
1369 			goto done;
1370 		if (n == 0) {
1371 			if (curstate != STATE_EXPECT_MORE_REF_UPDATES) {
1372 				err = got_error_msg(GOT_ERR_BAD_PACKET,
1373 				    "unexpected flush packet received");
1374 				goto done;
1375 			}
1376 			err = forward_flushpkt(&ibuf);
1377 			if (err)
1378 				goto done;
1379 			curstate = STATE_EXPECT_PACKFILE;
1380 		} else if (n >= (SHA1_DIGEST_STRING_LENGTH * 2) + 2) {
1381 			if (curstate != STATE_EXPECT_REF_UPDATE &&
1382 			    curstate != STATE_EXPECT_MORE_REF_UPDATES) {
1383 				err = got_error_msg(GOT_ERR_BAD_PACKET,
1384 				    "unexpected ref-update packet");
1385 				goto done;
1386 			}
1387 			if (curstate == STATE_EXPECT_REF_UPDATE) {
1388 				err = recv_ref_update(&report_status,
1389 				    outfd, &ibuf, buf, n, 1, chattygot);
1390 			} else {
1391 				err = recv_ref_update(NULL, outfd, &ibuf,
1392 				    buf, n, 0, chattygot);
1393 			}
1394 			if (err)
1395 				goto done;
1396 			curstate = STATE_EXPECT_MORE_REF_UPDATES;
1397 		} else {
1398 			err = got_error(GOT_ERR_BAD_PACKET);
1399 			goto done;
1400 		}
1401 	}
1402 
1403 	while (curstate != STATE_PACKFILE_RECEIVED) {
1404 		err = gotd_imsg_poll_recv(&imsg, &ibuf, 0);
1405 		if (err)
1406 			goto done;
1407 		switch (imsg.hdr.type) {
1408 		case GOTD_IMSG_ERROR:
1409 			err = gotd_imsg_recv_error(NULL, &imsg);
1410 			goto done;
1411 		case GOTD_IMSG_PACKFILE_PIPE:
1412 			err = recv_packfile(&imsg, infd);
1413 			if (err) {
1414 				if (err->code != GOT_ERR_EOF)
1415 					goto done;
1416 				/*
1417 				 * EOF is reported when the client hangs up,
1418 				 * which can happen with Git clients.
1419 				 * The socket should stay half-open so we
1420 				 * can still send our reports if requested.
1421 				 */
1422 				err = NULL;
1423 			}
1424 			curstate = STATE_PACKFILE_RECEIVED;
1425 			break;
1426 		default:
1427 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1428 			break;
1429 		}
1430 
1431 		imsg_free(&imsg);
1432 		if (err)
1433 			goto done;
1434 	}
1435 
1436 	while (curstate != STATE_REFS_UPDATED && err == NULL) {
1437 		err = gotd_imsg_poll_recv(&imsg, &ibuf, 0);
1438 		if (err)
1439 			break;
1440 		switch (imsg.hdr.type) {
1441 		case GOTD_IMSG_ERROR:
1442 			err = gotd_imsg_recv_error(NULL, &imsg);
1443 			break;
1444 		case GOTD_IMSG_PACKFILE_STATUS:
1445 			if (!report_status)
1446 				break;
1447 			err = report_unpack_status(&imsg, outfd, chattygot);
1448 			break;
1449 		case GOTD_IMSG_REF_UPDATE_OK:
1450 			if (!report_status)
1451 				break;
1452 			err = recv_ref_update_ok(&imsg, outfd, chattygot);
1453 			break;
1454 		case GOTD_IMSG_REF_UPDATE_NG:
1455 			if (!report_status)
1456 				break;
1457 			err = recv_ref_update_ng(&imsg, outfd, chattygot);
1458 			break;
1459 		case GOTD_IMSG_REFS_UPDATED:
1460 			curstate = STATE_REFS_UPDATED;
1461 			err = got_pkt_flushpkt(outfd, chattygot);
1462 			break;
1463 		default:
1464 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1465 			break;
1466 		}
1467 
1468 		imsg_free(&imsg);
1469 	}
1470 done:
1471 	imsg_clear(&ibuf);
1472 	if (err)
1473 		echo_error(err, outfd, chattygot);
1474 	return err;
1475 }
1476 
1477 const struct got_error *
1478 got_serve(int infd, int outfd, const char *command, const char *repo_path,
1479     int gotd_sock, int chattygot)
1480 {
1481 	const struct got_error *err = NULL;
1482 
1483 	if (strcmp(command, GOT_SERVE_CMD_FETCH) == 0)
1484 		err = serve_read(infd, outfd, gotd_sock, repo_path, chattygot);
1485 	else if (strcmp(command, GOT_SERVE_CMD_SEND) == 0)
1486 		err = serve_write(infd, outfd, gotd_sock, repo_path,
1487 		    chattygot);
1488 	else
1489 		err = got_error(GOT_ERR_BAD_PACKET);
1490 
1491 	return err;
1492 }