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Date:: Sat Feb 4 13:58:38 2023 UTC
Message:: rename sha1.c to hash.c
Actions:: History | Blame | Raw File
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 	char buf[GOT_PKT_MAX];
226 	uint8_t zero[SHA1_DIGEST_LENGTH];
227 	char hex[SHA1_DIGEST_STRING_LENGTH];
228 	size_t len, capalen = 0;
229 
230 	memset(&zero, 0, sizeof(zero));
231 
232 	if (got_sha1_digest_to_str(zero, hex, sizeof(hex)) == NULL)
233 		return got_error(GOT_ERR_BAD_OBJ_ID);
234 
235 	len = snprintf(buf, sizeof(buf), "%s capabilities^{}", hex);
236 	if (len >= sizeof(buf))
237 		return got_error(GOT_ERR_NO_SPACE);
238 
239 	if (client_is_reading) {
240 		err = got_gitproto_append_capabilities(&capalen, buf, len,
241 		    sizeof(buf), read_capabilities, nitems(read_capabilities));
242 		if (err)
243 			return err;
244 	} else {
245 		err = got_gitproto_append_capabilities(&capalen, buf, len,
246 		    sizeof(buf), write_capabilities,
247 		    nitems(write_capabilities));
248 		if (err)
249 			return err;
250 	}
251 
252 	return got_pkt_writepkt(outfd, buf, len + capalen, chattygot);
253 }
254 
255 static void
256 echo_error(const struct got_error *err, int outfd, int chattygot)
257 {
258 	char buf[4 + GOT_ERR_MAX_MSG_SIZE];
259 	size_t len;
260 
261 	/*
262 	 * Echo the error to the client on a pkt-line.
263 	 * The client should then terminate its session.
264 	 */
265 	buf[0] = 'E'; buf[1] = 'R'; buf[2] = 'R'; buf[3] = ' '; buf[4] = '\0';
266 	len = strlcat(buf, err->msg, sizeof(buf));
267 	got_pkt_writepkt(outfd, buf, len, chattygot);
268 }
269 
270 static const struct got_error *
271 announce_refs(int outfd, struct imsgbuf *ibuf, int client_is_reading,
272     const char *repo_path, int chattygot)
273 {
274 	const struct got_error *err = NULL;
275 	struct imsg imsg;
276 	size_t datalen;
277 	struct gotd_imsg_list_refs lsref;
278 	struct gotd_imsg_reflist ireflist;
279 	struct gotd_imsg_ref iref;
280 	struct gotd_imsg_symref isymref;
281 	size_t nrefs = 0;
282 	int have_nrefs = 0, sent_capabilities = 0;
283 	char *symrefname = NULL, *symreftarget = NULL, *symrefstr = NULL;
284 	char *refname = NULL;
285 
286 	memset(&imsg, 0, sizeof(imsg));
287 	memset(&lsref, 0, sizeof(lsref));
288 
289 	if (strlcpy(lsref.repo_name, repo_path, sizeof(lsref.repo_name)) >=
290 	    sizeof(lsref.repo_name))
291 		return got_error(GOT_ERR_NO_SPACE);
292 	lsref.client_is_reading = client_is_reading;
293 
294 	if (imsg_compose(ibuf, GOTD_IMSG_LIST_REFS, 0, 0, -1,
295 	    &lsref, sizeof(lsref)) == -1)
296 		return got_error_from_errno("imsg_compose LIST_REFS");
297 
298 	err = gotd_imsg_flush(ibuf);
299 	if (err)
300 		return err;
301 
302 	while (!have_nrefs || nrefs > 0) {
303 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
304 		if (err)
305 			goto done;
306 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
307 		switch (imsg.hdr.type) {
308 		case GOTD_IMSG_ERROR:
309 			err = gotd_imsg_recv_error(NULL, &imsg);
310 			goto done;
311 		case GOTD_IMSG_REFLIST:
312 			if (have_nrefs || nrefs > 0) {
313 				err = got_error(GOT_ERR_PRIVSEP_MSG);
314 				goto done;
315 			}
316 			if (datalen != sizeof(ireflist)) {
317 				err = got_error(GOT_ERR_PRIVSEP_MSG);
318 				goto done;
319 			}
320 			memcpy(&ireflist, imsg.data, sizeof(ireflist));
321 			nrefs = ireflist.nrefs;
322 			have_nrefs = 1;
323 			if (nrefs == 0)
324 				err = send_zero_refs(outfd, client_is_reading,
325 				    chattygot);
326 			break;
327 		case GOTD_IMSG_REF:
328 			if (!have_nrefs || nrefs == 0) {
329 				err = got_error(GOT_ERR_PRIVSEP_MSG);
330 				goto done;
331 			}
332 			if (datalen < sizeof(iref)) {
333 				err = got_error(GOT_ERR_PRIVSEP_MSG);
334 				goto done;
335 			}
336 			memcpy(&iref, imsg.data, sizeof(iref));
337 			if (datalen != sizeof(iref) + iref.name_len) {
338 				err = got_error(GOT_ERR_PRIVSEP_LEN);
339 				goto done;
340 			}
341 			refname = strndup(imsg.data + sizeof(iref),
342 			    iref.name_len);
343 			if (refname == NULL) {
344 				err = got_error_from_errno("strndup");
345 				goto done;
346 			}
347 			err = send_ref(outfd, iref.id, refname,
348 			    !sent_capabilities, client_is_reading,
349 			    NULL, chattygot);
350 			free(refname);
351 			refname = NULL;
352 			if (err)
353 				goto done;
354 			sent_capabilities = 1;
355 			if (nrefs > 0)
356 				nrefs--;
357 			break;
358 		case GOTD_IMSG_SYMREF:
359 			if (!have_nrefs || nrefs == 0) {
360 				err = got_error(GOT_ERR_PRIVSEP_MSG);
361 				goto done;
362 			}
363 			if (datalen < sizeof(isymref)) {
364 				err = got_error(GOT_ERR_PRIVSEP_LEN);
365 				goto done;
366 			}
367 			memcpy(&isymref, imsg.data, sizeof(isymref));
368 			if (datalen != sizeof(isymref) + isymref.name_len +
369 			    isymref.target_len) {
370 				err = got_error(GOT_ERR_PRIVSEP_LEN);
371 				goto done;
372 			}
373 
374 			/*
375 			 * For now, we only announce one symbolic ref,
376 			 * as part of our capability advertisement.
377 			 */
378 			if (sent_capabilities || symrefstr != NULL ||
379 			    symrefname != NULL || symreftarget != NULL)
380 				break;
381 
382 			symrefname = strndup(imsg.data + sizeof(isymref),
383 			    isymref.name_len);
384 			if (symrefname == NULL) {
385 				err = got_error_from_errno("malloc");
386 				goto done;
387 			}
388 
389 			symreftarget = strndup(
390 			    imsg.data + sizeof(isymref) + isymref.name_len,
391 			    isymref.target_len);
392 			if (symreftarget == NULL) {
393 				err = got_error_from_errno("strndup");
394 				goto done;
395 			}
396 
397 			if (asprintf(&symrefstr, "%s:%s", symrefname,
398 			    symreftarget) == -1) {
399 				err = got_error_from_errno("asprintf");
400 				goto done;
401 			}
402 			err = send_ref(outfd, isymref.target_id, symrefname,
403 			    !sent_capabilities, client_is_reading, symrefstr,
404 			    chattygot);
405 			free(refname);
406 			refname = NULL;
407 			if (err)
408 				goto done;
409 			sent_capabilities = 1;
410 			if (nrefs > 0)
411 				nrefs--;
412 			break;
413 		default:
414 			err = got_error(GOT_ERR_PRIVSEP_MSG);
415 			break;
416 		}
417 
418 		imsg_free(&imsg);
419 	}
420 
421 	err = got_pkt_flushpkt(outfd, chattygot);
422 	if (err)
423 		goto done;
424 done:
425 	free(symrefstr);
426 	free(symrefname);
427 	free(symreftarget);
428 	return err;
429 }
430 
431 static const struct got_error *
432 parse_want_line(char **common_capabilities, uint8_t *id, char *buf, size_t len)
433 {
434 	const struct got_error *err;
435 	char *id_str = NULL, *client_capabilities = NULL;
436 
437 	err = got_gitproto_parse_want_line(&id_str,
438 	    &client_capabilities, buf, len);
439 	if (err)
440 		return err;
441 
442 	if (!got_parse_sha1_digest(id, id_str)) {
443 		err = got_error_msg(GOT_ERR_BAD_PACKET,
444 		    "want-line with bad object ID");
445 		goto done;
446 	}
447 
448 	if (client_capabilities) {
449 		err = got_gitproto_match_capabilities(common_capabilities,
450 		    NULL, client_capabilities, read_capabilities,
451 		    nitems(read_capabilities));
452 		if (err)
453 			goto done;
454 	}
455 done:
456 	free(id_str);
457 	free(client_capabilities);
458 	return err;
459 }
460 
461 static const struct got_error *
462 parse_have_line(uint8_t *id, char *buf, size_t len)
463 {
464 	const struct got_error *err;
465 	char *id_str = NULL;
466 
467 	err = got_gitproto_parse_have_line(&id_str, buf, len);
468 	if (err)
469 		return err;
470 
471 	if (!got_parse_sha1_digest(id, id_str)) {
472 		err = got_error_msg(GOT_ERR_BAD_PACKET,
473 		    "have-line with bad object ID");
474 		goto done;
475 	}
476 done:
477 	free(id_str);
478 	return err;
479 }
480 
481 static const struct got_error *
482 send_capability(struct got_capability *capa, struct imsgbuf *ibuf)
483 {
484 	const struct got_error *err = NULL;
485 	struct gotd_imsg_capability icapa;
486 	size_t len;
487 	struct ibuf *wbuf;
488 
489 	memset(&icapa, 0, sizeof(icapa));
490 
491 	icapa.key_len = strlen(capa->key);
492 	len = sizeof(icapa) + icapa.key_len;
493 	if (capa->value) {
494 		icapa.value_len = strlen(capa->value);
495 		len += icapa.value_len;
496 	}
497 
498 	wbuf = imsg_create(ibuf, GOTD_IMSG_CAPABILITY, 0, 0, len);
499 	if (wbuf == NULL) {
500 		err = got_error_from_errno("imsg_create CAPABILITY");
501 		return err;
502 	}
503 
504 	if (imsg_add(wbuf, &icapa, sizeof(icapa)) == -1)
505 		return got_error_from_errno("imsg_add CAPABILITY");
506 	if (imsg_add(wbuf, capa->key, icapa.key_len) == -1)
507 		return got_error_from_errno("imsg_add CAPABILITY");
508 	if (capa->value) {
509 		if (imsg_add(wbuf, capa->value, icapa.value_len) == -1)
510 			return got_error_from_errno("imsg_add CAPABILITY");
511 	}
512 
513 	wbuf->fd = -1;
514 	imsg_close(ibuf, wbuf);
515 
516 	return NULL;
517 }
518 
519 static const struct got_error *
520 send_capabilities(int *use_sidebands, int *report_status,
521     char *capabilities_str, struct imsgbuf *ibuf)
522 {
523 	const struct got_error *err = NULL;
524 	struct gotd_imsg_capabilities icapas;
525 	struct got_capability *capa = NULL;
526 	size_t ncapa, i;
527 
528 	err = got_gitproto_split_capabilities_str(&capa, &ncapa,
529 	    capabilities_str);
530 	if (err)
531 		return err;
532 
533 	icapas.ncapabilities = ncapa;
534 	if (imsg_compose(ibuf, GOTD_IMSG_CAPABILITIES, 0, 0, -1,
535 	    &icapas, sizeof(icapas)) == -1) {
536 		err = got_error_from_errno("imsg_compose IMSG_CAPABILITIES");
537 		goto done;
538 	}
539 
540 	for (i = 0; i < ncapa; i++) {
541 		err = send_capability(&capa[i], ibuf);
542 		if (err)
543 			goto done;
544 		if (use_sidebands &&
545 		    strcmp(capa[i].key, GOT_CAPA_SIDE_BAND_64K) == 0)
546 			*use_sidebands = 1;
547 		if (report_status &&
548 		    strcmp(capa[i].key, GOT_CAPA_REPORT_STATUS) == 0)
549 			*report_status = 1;
550 	}
551 done:
552 	free(capa);
553 	return err;
554 }
555 
556 static const struct got_error *
557 forward_flushpkt(struct imsgbuf *ibuf)
558 {
559 	if (imsg_compose(ibuf, GOTD_IMSG_FLUSH, 0, 0, -1, NULL, 0) == -1)
560 		return got_error_from_errno("imsg_compose FLUSH");
561 
562 	return gotd_imsg_flush(ibuf);
563 }
564 
565 static const struct got_error *
566 recv_ack(struct imsg *imsg, uint8_t *expected_id)
567 {
568 	struct gotd_imsg_ack iack;
569 	size_t datalen;
570 
571 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
572 	if (datalen != sizeof(iack))
573 		return got_error(GOT_ERR_PRIVSEP_LEN);
574 
575 	memcpy(&iack, imsg->data, sizeof(iack));
576 	if (memcmp(iack.object_id, expected_id, SHA1_DIGEST_LENGTH) != 0)
577 		return got_error(GOT_ERR_BAD_OBJ_ID);
578 
579 	return NULL;
580 }
581 
582 static const struct got_error *
583 recv_nak(struct imsg *imsg, uint8_t *expected_id)
584 {
585 	struct gotd_imsg_ack inak;
586 	size_t datalen;
587 
588 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
589 	if (datalen != sizeof(inak))
590 		return got_error(GOT_ERR_PRIVSEP_LEN);
591 
592 	memcpy(&inak, imsg->data, sizeof(inak));
593 	if (memcmp(inak.object_id, expected_id, SHA1_DIGEST_LENGTH) != 0)
594 		return got_error(GOT_ERR_BAD_OBJ_ID);
595 
596 	return NULL;
597 }
598 
599 
600 static const struct got_error *
601 recv_want(int *use_sidebands, int outfd, struct imsgbuf *ibuf,
602     char *buf, size_t len, int expect_capabilities, int chattygot)
603 {
604 	const struct got_error *err;
605 	struct gotd_imsg_want iwant;
606 	char *capabilities_str;
607 	int done = 0;
608 	struct imsg imsg;
609 
610 	memset(&iwant, 0, sizeof(iwant));
611 	memset(&imsg, 0, sizeof(imsg));
612 
613 	err = parse_want_line(&capabilities_str, iwant.object_id, buf, len);
614 	if (err)
615 		return err;
616 
617 	if (capabilities_str) {
618 		if (!expect_capabilities) {
619 			err = got_error_msg(GOT_ERR_BAD_PACKET,
620 			    "unexpected capability announcement received");
621 			goto done;
622 		}
623 		err = send_capabilities(use_sidebands, NULL, capabilities_str,
624 		    ibuf);
625 		if (err)
626 			goto done;
627 
628 	}
629 
630 	if (imsg_compose(ibuf, GOTD_IMSG_WANT, 0, 0, -1,
631 	    &iwant, sizeof(iwant)) == -1) {
632 		err = got_error_from_errno("imsg_compose WANT");
633 		goto done;
634 	}
635 
636 	err = gotd_imsg_flush(ibuf);
637 	if (err)
638 		goto done;
639 
640 	/*
641 	 * Wait for an ACK, or an error in case the desired object
642 	 * does not exist.
643 	 */
644 	while (!done && err == NULL) {
645 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
646 		if (err)
647 			break;
648 		switch (imsg.hdr.type) {
649 		case GOTD_IMSG_ERROR:
650 			err = gotd_imsg_recv_error(NULL, &imsg);
651 			break;
652 		case GOTD_IMSG_ACK:
653 			err = recv_ack(&imsg, iwant.object_id);
654 			if (err)
655 				break;
656 			done = 1;
657 			break;
658 		default:
659 			err = got_error(GOT_ERR_PRIVSEP_MSG);
660 			break;
661 		}
662 
663 		imsg_free(&imsg);
664 	}
665 done:
666 	free(capabilities_str);
667 	return err;
668 }
669 
670 static const struct got_error *
671 send_ack(int outfd, uint8_t *id, int chattygot)
672 {
673 	char hex[SHA1_DIGEST_STRING_LENGTH];
674 	char buf[GOT_PKT_MAX];
675 	int len;
676 
677 	if (got_sha1_digest_to_str(id, hex, sizeof(hex)) == NULL)
678 		return got_error(GOT_ERR_BAD_OBJ_ID);
679 
680 	len = snprintf(buf, sizeof(buf), "ACK %s\n", hex);
681 	if (len >= sizeof(buf))
682 		return got_error(GOT_ERR_NO_SPACE);
683 
684 	return got_pkt_writepkt(outfd, buf, len, chattygot);
685 }
686 
687 static const struct got_error *
688 send_nak(int outfd, int chattygot)
689 {
690 	char buf[5];
691 	int len;
692 
693 	len = snprintf(buf, sizeof(buf), "NAK\n");
694 	if (len >= sizeof(buf))
695 		return got_error(GOT_ERR_NO_SPACE);
696 
697 	return got_pkt_writepkt(outfd, buf, len, chattygot);
698 }
699 
700 static const struct got_error *
701 recv_have(int *have_ack, int outfd, struct imsgbuf *ibuf, char *buf,
702     size_t len, int chattygot)
703 {
704 	const struct got_error *err;
705 	struct gotd_imsg_have ihave;
706 	int done = 0;
707 	struct imsg imsg;
708 
709 	memset(&ihave, 0, sizeof(ihave));
710 	memset(&imsg, 0, sizeof(imsg));
711 
712 	err = parse_have_line(ihave.object_id, buf, len);
713 	if (err)
714 		return err;
715 
716 	if (imsg_compose(ibuf, GOTD_IMSG_HAVE, 0, 0, -1,
717 	    &ihave, sizeof(ihave)) == -1)
718 		return got_error_from_errno("imsg_compose HAVE");
719 
720 	err = gotd_imsg_flush(ibuf);
721 	if (err)
722 		return err;
723 
724 	/*
725 	 * Wait for an ACK or a NAK, indicating whether a common
726 	 * commit object has been found.
727 	 */
728 	while (!done && err == NULL) {
729 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
730 		if (err)
731 			return err;
732 		switch (imsg.hdr.type) {
733 		case GOTD_IMSG_ERROR:
734 			err = gotd_imsg_recv_error(NULL, &imsg);
735 			break;
736 		case GOTD_IMSG_ACK:
737 			err = recv_ack(&imsg, ihave.object_id);
738 			if (err)
739 				break;
740 			if (!*have_ack) {
741 				err = send_ack(outfd, ihave.object_id,
742 				    chattygot);
743 				if (err)
744 					return err;
745 				*have_ack = 1;
746 			}
747 			done = 1;
748 			break;
749 		case GOTD_IMSG_NAK:
750 			err = recv_nak(&imsg, ihave.object_id);
751 			if (err)
752 				break;
753 			done = 1;
754 			break;
755 		default:
756 			err = got_error(GOT_ERR_PRIVSEP_MSG);
757 			break;
758 		}
759 
760 		imsg_free(&imsg);
761 	}
762 
763 	return err;
764 }
765 
766 static const struct got_error *
767 recv_done(int *packfd, int outfd, struct imsgbuf *ibuf, int chattygot)
768 {
769 	const struct got_error *err;
770 	struct imsg imsg;
771 
772 	*packfd = -1;
773 
774 	if (imsg_compose(ibuf, GOTD_IMSG_DONE, 0, 0, -1, NULL, 0) == -1)
775 		return got_error_from_errno("imsg_compose DONE");
776 
777 	err = gotd_imsg_flush(ibuf);
778 	if (err)
779 		return err;
780 
781 	while (*packfd == -1 && err == NULL) {
782 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
783 		if (err)
784 			break;
785 
786 		switch (imsg.hdr.type) {
787 		case GOTD_IMSG_ERROR:
788 			err = gotd_imsg_recv_error(NULL, &imsg);
789 			break;
790 		case GOTD_IMSG_PACKFILE_PIPE:
791 			if (imsg.fd != -1)
792 				*packfd = imsg.fd;
793 			else
794 				err = got_error(GOT_ERR_PRIVSEP_NO_FD);
795 			break;
796 		default:
797 			err = got_error(GOT_ERR_PRIVSEP_MSG);
798 			break;
799 		}
800 
801 		imsg_free(&imsg);
802 	}
803 
804 	return err;
805 }
806 
807 static const struct got_error *
808 relay_progress_reports(struct imsgbuf *ibuf, int outfd, int chattygot)
809 {
810 	const struct got_error *err = NULL;
811 	int pack_starting = 0;
812 	struct gotd_imsg_packfile_progress iprog;
813 	char buf[GOT_PKT_MAX];
814 	struct imsg imsg;
815 	size_t datalen;
816 	int p_deltify = 0, n;
817 	const char *eol = "\r";
818 
819 	memset(&imsg, 0, sizeof(imsg));
820 
821 	while (!pack_starting && err == NULL) {
822 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
823 		if (err)
824 			break;
825 
826 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
827 		switch (imsg.hdr.type) {
828 		case GOTD_IMSG_ERROR:
829 			err = gotd_imsg_recv_error(NULL, &imsg);
830 			break;
831 		case GOTD_IMSG_PACKFILE_READY:
832 			eol = "\n";
833 			pack_starting = 1;
834 			/* fallthrough */
835 		case GOTD_IMSG_PACKFILE_PROGRESS:
836 			if (datalen != sizeof(iprog)) {
837 				err = got_error(GOT_ERR_PRIVSEP_LEN);
838 				break;
839 			}
840 			memcpy(&iprog, imsg.data, sizeof(iprog));
841 			if (iprog.nobj_total > 0) {
842 				p_deltify = (iprog.nobj_deltify * 100) /
843 				    iprog.nobj_total;
844 			}
845 			buf[0] = GOT_SIDEBAND_PROGRESS_INFO;
846 			n = snprintf(&buf[1], sizeof(buf) - 1,
847 			    "%d commits colored, "
848 			    "%d objects found, "
849 			    "deltify %d%%%s",
850 			    iprog.ncolored,
851 			    iprog.nfound,
852 			    p_deltify, eol);
853 			if (n >= sizeof(buf) - 1)
854 				break;
855 			err = got_pkt_writepkt(outfd, buf, 1 + n, chattygot);
856 			break;
857 		default:
858 			err = got_error(GOT_ERR_PRIVSEP_MSG);
859 			break;
860 		}
861 
862 		imsg_free(&imsg);
863 	}
864 
865 	return err;
866 }
867 
868 static const struct got_error *
869 serve_read(int infd, int outfd, int gotd_sock, const char *repo_path,
870     int chattygot)
871 {
872 	const struct got_error *err = NULL;
873 	char buf[GOT_PKT_MAX];
874 	struct imsgbuf ibuf;
875 	enum protostate {
876 		STATE_EXPECT_WANT,
877 		STATE_EXPECT_MORE_WANT,
878 		STATE_EXPECT_HAVE,
879 		STATE_EXPECT_DONE,
880 		STATE_DONE,
881 	};
882 	enum protostate curstate = STATE_EXPECT_WANT;
883 	int have_ack = 0, use_sidebands = 0, seen_have = 0;
884 	int packfd = -1;
885 	size_t pack_chunksize;
886 
887 	imsg_init(&ibuf, gotd_sock);
888 
889 	err = announce_refs(outfd, &ibuf, 1, repo_path, chattygot);
890 	if (err)
891 		goto done;
892 
893 	while (curstate != STATE_DONE) {
894 		int n;
895 		buf[0] = '\0';
896 		err = got_pkt_readpkt(&n, infd, buf, sizeof(buf), chattygot);
897 		if (err)
898 			goto done;
899 		if (n == 0) {
900 			if (curstate != STATE_EXPECT_WANT &&
901 			    curstate != STATE_EXPECT_MORE_WANT &&
902 			    curstate != STATE_EXPECT_HAVE &&
903 			    curstate != STATE_EXPECT_DONE) {
904 				err = got_error_msg(GOT_ERR_BAD_PACKET,
905 				    "unexpected flush packet received");
906 				goto done;
907 			}
908 
909 			if (curstate == STATE_EXPECT_WANT) {
910 				ssize_t r;
911 				/*
912 				 * If the client does not want to fetch
913 				 * anything we should receive a flush
914 				 * packet followed by EOF.
915 				 */
916 				r = read(infd, buf, sizeof(buf));
917 				if (r == -1) {
918 					err = got_error_from_errno("read");
919 					goto done;
920 				}
921 				if (r == 0) /* EOF */
922 					goto done;
923 
924 				/* Zero-length field followed by payload. */
925 				err = got_error_msg(GOT_ERR_BAD_PACKET,
926 				    "unexpected flush packet received");
927 				goto done;
928 			}
929 
930 			if (curstate == STATE_EXPECT_WANT ||
931 			    curstate == STATE_EXPECT_MORE_WANT ||
932 			    curstate == STATE_EXPECT_HAVE) {
933 				err = forward_flushpkt(&ibuf);
934 				if (err)
935 					goto done;
936 			}
937 			if (curstate == STATE_EXPECT_HAVE && !have_ack) {
938 				err = send_nak(outfd, chattygot);
939 				if (err)
940 					goto done;
941 			}
942 			if (curstate == STATE_EXPECT_MORE_WANT)
943 				curstate = STATE_EXPECT_HAVE;
944 			else
945 				curstate = STATE_EXPECT_DONE;
946 		} else if (n >= 5 && strncmp(buf, "want ", 5) == 0) {
947 			if (curstate != STATE_EXPECT_WANT &&
948 			    curstate != STATE_EXPECT_MORE_WANT) {
949 				err = got_error_msg(GOT_ERR_BAD_PACKET,
950 				    "unexpected 'want' packet");
951 				goto done;
952 			}
953 			err = recv_want(&use_sidebands, outfd, &ibuf, buf, n,
954 			    curstate == STATE_EXPECT_WANT ? 1 : 0, chattygot);
955 			if (err)
956 				goto done;
957 			if (curstate == STATE_EXPECT_WANT)
958 				curstate = STATE_EXPECT_MORE_WANT;
959 		} else if (n >= 5 && strncmp(buf, "have ", 5) == 0) {
960 			if (curstate != STATE_EXPECT_HAVE &&
961 			    curstate != STATE_EXPECT_DONE) {
962 				err = got_error_msg(GOT_ERR_BAD_PACKET,
963 				    "unexpected 'have' packet");
964 				goto done;
965 			}
966 			if (curstate == STATE_EXPECT_HAVE) {
967 				err = recv_have(&have_ack, outfd, &ibuf,
968 				    buf, n, chattygot);
969 				if (err)
970 					goto done;
971 				seen_have = 1;
972 				if (have_ack)
973 					curstate = STATE_EXPECT_DONE;
974 			}
975 		} else if (n == 5 && strncmp(buf, "done\n", 5) == 0) {
976 			if (curstate != STATE_EXPECT_HAVE &&
977 			    curstate != STATE_EXPECT_DONE) {
978 				err = got_error_msg(GOT_ERR_BAD_PACKET,
979 				    "unexpected 'done' packet");
980 				goto done;
981 			}
982 			err = recv_done(&packfd, outfd, &ibuf, chattygot);
983 			if (err)
984 				goto done;
985 			curstate = STATE_DONE;
986 			break;
987 		} else {
988 			err = got_error(GOT_ERR_BAD_PACKET);
989 			goto done;
990 		}
991 	}
992 
993 	if (!seen_have) {
994 		err = send_nak(outfd, chattygot);
995 		if (err)
996 			goto done;
997 	}
998 
999 	if (use_sidebands) {
1000 		err = relay_progress_reports(&ibuf, outfd, chattygot);
1001 		if (err)
1002 			goto done;
1003 		pack_chunksize = GOT_SIDEBAND_64K_PACKFILE_DATA_MAX;
1004 	} else
1005 		pack_chunksize = sizeof(buf);
1006 
1007 	for (;;) {
1008 		ssize_t r;
1009 
1010 		r = read(packfd, use_sidebands ? &buf[1] : buf,
1011 		    pack_chunksize);
1012 		if (r == -1) {
1013 			err = got_error_from_errno("read");
1014 			break;
1015 		} else if (r == 0) {
1016 			err = got_pkt_flushpkt(outfd, chattygot);
1017 			break;
1018 		}
1019 
1020 		if (use_sidebands) {
1021 			buf[0] = GOT_SIDEBAND_PACKFILE_DATA;
1022 			err = got_pkt_writepkt(outfd, buf, 1 + r, chattygot);
1023 			if (err)
1024 				break;
1025 		} else {
1026 			err = got_poll_write_full(outfd, buf, r);
1027 			if (err) {
1028 				if (err->code == GOT_ERR_EOF)
1029 					err = NULL;
1030 				break;
1031 			}
1032 		}
1033 	}
1034 done:
1035 	imsg_clear(&ibuf);
1036 	if (packfd != -1 && close(packfd) == -1 && err == NULL)
1037 		err = got_error_from_errno("close");
1038 	if (err)
1039 		echo_error(err, outfd, chattygot);
1040 	return err;
1041 }
1042 
1043 static const struct got_error *
1044 parse_ref_update_line(char **common_capabilities, char **refname,
1045     uint8_t *old_id, uint8_t *new_id, char *buf, size_t len)
1046 {
1047 	const struct got_error *err;
1048 	char *old_id_str = NULL, *new_id_str = NULL;
1049 	char *client_capabilities = NULL;
1050 
1051 	*refname = NULL;
1052 
1053 	err = got_gitproto_parse_ref_update_line(&old_id_str, &new_id_str,
1054 	    refname, &client_capabilities, buf, len);
1055 	if (err)
1056 		return err;
1057 
1058 	if (!got_parse_sha1_digest(old_id, old_id_str) ||
1059 	    !got_parse_sha1_digest(new_id, new_id_str)) {
1060 		err = got_error_msg(GOT_ERR_BAD_PACKET,
1061 		    "ref-update with bad object ID");
1062 		goto done;
1063 	}
1064 	if (!got_ref_name_is_valid(*refname)) {
1065 		err = got_error_msg(GOT_ERR_BAD_PACKET,
1066 		    "ref-update with bad reference name");
1067 		goto done;
1068 	}
1069 
1070 	if (client_capabilities) {
1071 		err = got_gitproto_match_capabilities(common_capabilities,
1072 		    NULL, client_capabilities, write_capabilities,
1073 		    nitems(write_capabilities));
1074 		if (err)
1075 			goto done;
1076 	}
1077 done:
1078 	free(old_id_str);
1079 	free(new_id_str);
1080 	free(client_capabilities);
1081 	if (err) {
1082 		free(*refname);
1083 		*refname = NULL;
1084 	}
1085 	return err;
1086 }
1087 
1088 static const struct got_error *
1089 recv_ref_update(int *report_status, int outfd, struct imsgbuf *ibuf,
1090     char *buf, size_t len, int expect_capabilities, int chattygot)
1091 {
1092 	const struct got_error *err;
1093 	struct gotd_imsg_ref_update iref;
1094 	struct ibuf *wbuf;
1095 	char *capabilities_str = NULL, *refname = NULL;
1096 	int done = 0;
1097 	struct imsg imsg;
1098 
1099 	memset(&iref, 0, sizeof(iref));
1100 	memset(&imsg, 0, sizeof(imsg));
1101 
1102 	err = parse_ref_update_line(&capabilities_str, &refname,
1103 	    iref.old_id, iref.new_id, buf, len);
1104 	if (err)
1105 		return err;
1106 
1107 	if (capabilities_str) {
1108 		if (!expect_capabilities) {
1109 			err = got_error_msg(GOT_ERR_BAD_PACKET,
1110 			    "unexpected capability announcement received");
1111 			goto done;
1112 		}
1113 		err = send_capabilities(NULL, report_status, capabilities_str,
1114 		    ibuf);
1115 		if (err)
1116 			goto done;
1117 	}
1118 
1119 	iref.name_len = strlen(refname);
1120 	len = sizeof(iref) + iref.name_len;
1121 	wbuf = imsg_create(ibuf, GOTD_IMSG_REF_UPDATE, 0, 0, len);
1122 	if (wbuf == NULL) {
1123 		err = got_error_from_errno("imsg_create REF_UPDATE");
1124 		goto done;
1125 	}
1126 
1127 	if (imsg_add(wbuf, &iref, sizeof(iref)) == -1)
1128 		return got_error_from_errno("imsg_add REF_UPDATE");
1129 	if (imsg_add(wbuf, refname, iref.name_len) == -1)
1130 		return got_error_from_errno("imsg_add REF_UPDATE");
1131 	wbuf->fd = -1;
1132 	imsg_close(ibuf, wbuf);
1133 
1134 	err = gotd_imsg_flush(ibuf);
1135 	if (err)
1136 		goto done;
1137 
1138 	/* Wait for ACK or an error. */
1139 	while (!done && err == NULL) {
1140 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
1141 		if (err)
1142 			break;
1143 		switch (imsg.hdr.type) {
1144 		case GOTD_IMSG_ERROR:
1145 			err = gotd_imsg_recv_error(NULL, &imsg);
1146 			break;
1147 		case GOTD_IMSG_ACK:
1148 			err = recv_ack(&imsg, iref.new_id);
1149 			if (err)
1150 				break;
1151 			done = 1;
1152 			break;
1153 		default:
1154 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1155 			break;
1156 		}
1157 
1158 		imsg_free(&imsg);
1159 	}
1160 done:
1161 	free(capabilities_str);
1162 	free(refname);
1163 	return err;
1164 }
1165 
1166 static const struct got_error *
1167 recv_packfile(struct imsg *imsg, int infd)
1168 {
1169 	const struct got_error *err = NULL;
1170 	size_t datalen;
1171 	int packfd;
1172 	char buf[GOT_PKT_MAX];
1173 	int pack_done = 0;
1174 
1175 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1176 	if (datalen != 0)
1177 		return got_error(GOT_ERR_PRIVSEP_MSG);
1178 
1179 	if (imsg->fd == -1)
1180 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
1181 
1182 	packfd = imsg->fd;
1183 	while (!pack_done) {
1184 		ssize_t r = 0;
1185 
1186 		err = got_poll_fd(infd, POLLIN, 1);
1187 		if (err) {
1188 			if (err->code != GOT_ERR_TIMEOUT)
1189 				break;
1190 			err = NULL;
1191 		} else {
1192 			r = read(infd, buf, sizeof(buf));
1193 			if (r == -1) {
1194 				err = got_error_from_errno("read");
1195 				break;
1196 			}
1197 			if (r == 0) {
1198 				/*
1199 				 * Git clients hang up their side of the
1200 				 * connection after sending the pack file.
1201 				 */
1202 				err = NULL;
1203 				pack_done = 1;
1204 				break;
1205 			}
1206 		}
1207 
1208 		if (r == 0) {
1209 			/* Detect gotd(8) closing the pack pipe when done. */
1210 			err = got_poll_fd(packfd, POLLOUT, 1);
1211 			if (err) {
1212 				if (err->code != GOT_ERR_EOF)
1213 					break;
1214 				err = NULL;
1215 				pack_done = 1;
1216 			}
1217 		} else {
1218 			/* Write pack data and/or detect pipe being closed. */
1219 			err = got_poll_write_full(packfd, buf, r);
1220 			if (err) {
1221 				if (err->code == GOT_ERR_EOF)
1222 					err = NULL;
1223 				break;
1224 			}
1225 		}
1226 	}
1227 
1228 	close(packfd);
1229 	return err;
1230 }
1231 
1232 static const struct got_error *
1233 report_unpack_status(struct imsg *imsg, int outfd, int chattygot)
1234 {
1235 	const struct got_error *err = NULL;
1236 	struct gotd_imsg_packfile_status istatus;
1237 	char buf[GOT_PKT_MAX];
1238 	size_t datalen, len;
1239 	char *reason = NULL;
1240 
1241 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1242 	if (datalen < sizeof(istatus))
1243 		return got_error(GOT_ERR_PRIVSEP_LEN);
1244 	memcpy(&istatus, imsg->data, sizeof(istatus));
1245 	if (datalen != sizeof(istatus) + istatus.reason_len)
1246 		return got_error(GOT_ERR_PRIVSEP_LEN);
1247 
1248 	reason = strndup(imsg->data + sizeof(istatus), istatus.reason_len);
1249 	if (reason == NULL) {
1250 		err = got_error_from_errno("strndup");
1251 		goto done;
1252 	}
1253 
1254 	if (err == NULL)
1255 		len = snprintf(buf, sizeof(buf), "unpack ok\n");
1256 	else
1257 		len = snprintf(buf, sizeof(buf), "unpack %s\n", reason);
1258 	if (len >= sizeof(buf)) {
1259 		err = got_error(GOT_ERR_NO_SPACE);
1260 		goto done;
1261 	}
1262 
1263 	err = got_pkt_writepkt(outfd, buf, len, chattygot);
1264 done:
1265 	free(reason);
1266 	return err;
1267 }
1268 
1269 static const struct got_error *
1270 recv_ref_update_ok(struct imsg *imsg, int outfd, int chattygot)
1271 {
1272 	const struct got_error *err = NULL;
1273 	struct gotd_imsg_ref_update_ok iok;
1274 	size_t datalen, len;
1275 	char buf[GOT_PKT_MAX];
1276 	char *refname = NULL;
1277 
1278 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1279 	if (datalen < sizeof(iok))
1280 		return got_error(GOT_ERR_PRIVSEP_LEN);
1281 	memcpy(&iok, imsg->data, sizeof(iok));
1282 	if (datalen != sizeof(iok) + iok.name_len)
1283 		return got_error(GOT_ERR_PRIVSEP_LEN);
1284 
1285 	memcpy(&iok, imsg->data, sizeof(iok));
1286 
1287 	refname = strndup(imsg->data + sizeof(iok), iok.name_len);
1288 	if (refname == NULL)
1289 		return got_error_from_errno("strndup");
1290 
1291 	len = snprintf(buf, sizeof(buf), "ok %s\n", refname);
1292 	if (len >= sizeof(buf)) {
1293 		err = got_error(GOT_ERR_NO_SPACE);
1294 		goto done;
1295 	}
1296 
1297 	err = got_pkt_writepkt(outfd, buf, len, chattygot);
1298 done:
1299 	free(refname);
1300 	return err;
1301 }
1302 
1303 static const struct got_error *
1304 recv_ref_update_ng(struct imsg *imsg, int outfd, int chattygot)
1305 {
1306 	const struct got_error *err = NULL;
1307 	struct gotd_imsg_ref_update_ng ing;
1308 	size_t datalen, len;
1309 	char buf[GOT_PKT_MAX];
1310 	char *refname = NULL, *reason = NULL;
1311 
1312 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1313 	if (datalen < sizeof(ing))
1314 		return got_error(GOT_ERR_PRIVSEP_LEN);
1315 	memcpy(&ing, imsg->data, sizeof(ing));
1316 	if (datalen != sizeof(ing) + ing.name_len + ing.reason_len)
1317 		return got_error(GOT_ERR_PRIVSEP_LEN);
1318 
1319 	memcpy(&ing, imsg->data, sizeof(ing));
1320 
1321 	refname = strndup(imsg->data + sizeof(ing), ing.name_len);
1322 	if (refname == NULL)
1323 		return got_error_from_errno("strndup");
1324 
1325 	reason = strndup(imsg->data + sizeof(ing) + ing.name_len,
1326 	    ing.reason_len);
1327 	if (reason == NULL) {
1328 		err = got_error_from_errno("strndup");
1329 		goto done;
1330 	}
1331 
1332 	len = snprintf(buf, sizeof(buf), "ng %s %s\n", refname, reason);
1333 	if (len >= sizeof(buf)) {
1334 		err = got_error(GOT_ERR_NO_SPACE);
1335 		goto done;
1336 	}
1337 
1338 	err = got_pkt_writepkt(outfd, buf, len, chattygot);
1339 done:
1340 	free(refname);
1341 	free(reason);
1342 	return err;
1343 }
1344 
1345 static const struct got_error *
1346 serve_write(int infd, int outfd, int gotd_sock, const char *repo_path,
1347     int chattygot)
1348 {
1349 	const struct got_error *err = NULL;
1350 	char buf[GOT_PKT_MAX];
1351 	struct imsgbuf ibuf;
1352 	enum protostate {
1353 		STATE_EXPECT_REF_UPDATE,
1354 		STATE_EXPECT_MORE_REF_UPDATES,
1355 		STATE_EXPECT_PACKFILE,
1356 		STATE_PACKFILE_RECEIVED,
1357 		STATE_REFS_UPDATED,
1358 	};
1359 	enum protostate curstate = STATE_EXPECT_REF_UPDATE;
1360 	struct imsg imsg;
1361 	int report_status = 0;
1362 
1363 	imsg_init(&ibuf, gotd_sock);
1364 	memset(&imsg, 0, sizeof(imsg));
1365 
1366 	err = announce_refs(outfd, &ibuf, 0, repo_path, chattygot);
1367 	if (err)
1368 		goto done;
1369 
1370 	while (curstate != STATE_EXPECT_PACKFILE) {
1371 		int n;
1372 		buf[0] = '\0';
1373 		err = got_pkt_readpkt(&n, infd, buf, sizeof(buf), chattygot);
1374 		if (err)
1375 			goto done;
1376 		if (n == 0) {
1377 			if (curstate != STATE_EXPECT_MORE_REF_UPDATES) {
1378 				err = got_error_msg(GOT_ERR_BAD_PACKET,
1379 				    "unexpected flush packet received");
1380 				goto done;
1381 			}
1382 			err = forward_flushpkt(&ibuf);
1383 			if (err)
1384 				goto done;
1385 			curstate = STATE_EXPECT_PACKFILE;
1386 		} else if (n >= (SHA1_DIGEST_STRING_LENGTH * 2) + 2) {
1387 			if (curstate != STATE_EXPECT_REF_UPDATE &&
1388 			    curstate != STATE_EXPECT_MORE_REF_UPDATES) {
1389 				err = got_error_msg(GOT_ERR_BAD_PACKET,
1390 				    "unexpected ref-update packet");
1391 				goto done;
1392 			}
1393 			if (curstate == STATE_EXPECT_REF_UPDATE) {
1394 				err = recv_ref_update(&report_status,
1395 				    outfd, &ibuf, buf, n, 1, chattygot);
1396 			} else {
1397 				err = recv_ref_update(NULL, outfd, &ibuf,
1398 				    buf, n, 0, chattygot);
1399 			}
1400 			if (err)
1401 				goto done;
1402 			curstate = STATE_EXPECT_MORE_REF_UPDATES;
1403 		} else {
1404 			err = got_error(GOT_ERR_BAD_PACKET);
1405 			goto done;
1406 		}
1407 	}
1408 
1409 	while (curstate != STATE_PACKFILE_RECEIVED) {
1410 		err = gotd_imsg_poll_recv(&imsg, &ibuf, 0);
1411 		if (err)
1412 			goto done;
1413 		switch (imsg.hdr.type) {
1414 		case GOTD_IMSG_ERROR:
1415 			err = gotd_imsg_recv_error(NULL, &imsg);
1416 			goto done;
1417 		case GOTD_IMSG_PACKFILE_PIPE:
1418 			err = recv_packfile(&imsg, infd);
1419 			if (err) {
1420 				if (err->code != GOT_ERR_EOF)
1421 					goto done;
1422 				/*
1423 				 * EOF is reported when the client hangs up,
1424 				 * which can happen with Git clients.
1425 				 * The socket should stay half-open so we
1426 				 * can still send our reports if requested.
1427 				 */
1428 				err = NULL;
1429 			}
1430 			curstate = STATE_PACKFILE_RECEIVED;
1431 			break;
1432 		default:
1433 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1434 			break;
1435 		}
1436 
1437 		imsg_free(&imsg);
1438 		if (err)
1439 			goto done;
1440 	}
1441 
1442 	while (curstate != STATE_REFS_UPDATED && err == NULL) {
1443 		err = gotd_imsg_poll_recv(&imsg, &ibuf, 0);
1444 		if (err)
1445 			break;
1446 		switch (imsg.hdr.type) {
1447 		case GOTD_IMSG_ERROR:
1448 			err = gotd_imsg_recv_error(NULL, &imsg);
1449 			break;
1450 		case GOTD_IMSG_PACKFILE_STATUS:
1451 			if (!report_status)
1452 				break;
1453 			err = report_unpack_status(&imsg, outfd, chattygot);
1454 			break;
1455 		case GOTD_IMSG_REF_UPDATE_OK:
1456 			if (!report_status)
1457 				break;
1458 			err = recv_ref_update_ok(&imsg, outfd, chattygot);
1459 			break;
1460 		case GOTD_IMSG_REF_UPDATE_NG:
1461 			if (!report_status)
1462 				break;
1463 			err = recv_ref_update_ng(&imsg, outfd, chattygot);
1464 			break;
1465 		case GOTD_IMSG_REFS_UPDATED:
1466 			curstate = STATE_REFS_UPDATED;
1467 			err = got_pkt_flushpkt(outfd, chattygot);
1468 			break;
1469 		default:
1470 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1471 			break;
1472 		}
1473 
1474 		imsg_free(&imsg);
1475 	}
1476 done:
1477 	imsg_clear(&ibuf);
1478 	if (err)
1479 		echo_error(err, outfd, chattygot);
1480 	return err;
1481 }
1482 
1483 const struct got_error *
1484 got_serve(int infd, int outfd, const char *command, const char *repo_path,
1485     int gotd_sock, int chattygot)
1486 {
1487 	const struct got_error *err = NULL;
1488 
1489 	if (strcmp(command, GOT_SERVE_CMD_FETCH) == 0)
1490 		err = serve_read(infd, outfd, gotd_sock, repo_path, chattygot);
1491 	else if (strcmp(command, GOT_SERVE_CMD_SEND) == 0)
1492 		err = serve_write(infd, outfd, gotd_sock, repo_path,
1493 		    chattygot);
1494 	else
1495 		err = got_error(GOT_ERR_BAD_PACKET);
1496 
1497 	return err;
1498 }