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Date:: Thu Dec 8 13:59:36 2022 UTC
Message:: remove bogus abort() call from gotsh echo_error()
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1 /*
2  * Copyright (c) 2022 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <sys/types.h>
18 #include <sys/queue.h>
19 #include <sys/uio.h>
20 
21 #include <errno.h>
22 #include <event.h>
23 #include <poll.h>
24 #include <limits.h>
25 #include <sha1.h>
26 #include <stdio.h>
27 #include <stdint.h>
28 #include <stdlib.h>
29 #include <string.h>
30 #include <imsg.h>
31 #include <unistd.h>
32 
33 #include "got_error.h"
34 #include "got_serve.h"
35 #include "got_path.h"
36 #include "got_version.h"
37 #include "got_reference.h"
38 
39 #include "got_lib_pkt.h"
40 #include "got_lib_dial.h"
41 #include "got_lib_gitproto.h"
42 #include "got_lib_sha1.h"
43 #include "got_lib_poll.h"
44 
45 #include "gotd.h"
46 
47 #ifndef nitems
48 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
49 #endif
50 
51 static const struct got_capability read_capabilities[] = {
52 	{ GOT_CAPA_AGENT, "got/" GOT_VERSION_STR },
53 	{ GOT_CAPA_OFS_DELTA, NULL },
54 	{ GOT_CAPA_SIDE_BAND_64K, NULL },
55 };
56 
57 static const struct got_capability write_capabilities[] = {
58 	{ GOT_CAPA_AGENT, "got/" GOT_VERSION_STR },
59 	{ GOT_CAPA_OFS_DELTA, NULL },
60 	{ GOT_CAPA_REPORT_STATUS, NULL },
61 	{ GOT_CAPA_NO_THIN, NULL },
62 #if 0
63 	{ GOT_CAPA_DELETE_REFS, NULL },
64 #endif
65 };
66 
67 static const struct got_error *
68 parse_command(char **command, char **repo_path, const char *gitcmd)
69 {
70 	const struct got_error *err = NULL;
71 	size_t len, cmdlen, pathlen;
72 	char *path0 = NULL, *path, *abspath = NULL, *canonpath = NULL;
73 	const char *relpath;
74 
75 	*command = NULL;
76 	*repo_path = NULL;
77 
78 	len = strlen(gitcmd);
79 
80 	if (len >= strlen(GOT_SERVE_CMD_SEND) &&
81 	    strncmp(gitcmd, GOT_SERVE_CMD_SEND,
82 	    strlen(GOT_SERVE_CMD_SEND)) == 0)
83 		cmdlen = strlen(GOT_SERVE_CMD_SEND);
84 	else if (len >= strlen(GOT_SERVE_CMD_FETCH) &&
85 	    strncmp(gitcmd, GOT_SERVE_CMD_FETCH,
86 	    strlen(GOT_SERVE_CMD_FETCH)) == 0)
87 		cmdlen = strlen(GOT_SERVE_CMD_FETCH);
88 	else
89 		return got_error(GOT_ERR_BAD_PACKET);
90 
91 	if (len <= cmdlen + 1 || gitcmd[cmdlen] != ' ')
92 		return got_error(GOT_ERR_BAD_PACKET);
93 
94 	if (memchr(&gitcmd[cmdlen + 1], '\0', len - cmdlen) == NULL)
95 		return got_error(GOT_ERR_BAD_PATH);
96 
97 	/* Forbid linefeeds in paths, like Git does. */
98 	if (memchr(&gitcmd[cmdlen + 1], '\n', len - cmdlen) != NULL)
99 		return got_error(GOT_ERR_BAD_PATH);
100 
101 	path0 = strdup(&gitcmd[cmdlen + 1]);
102 	if (path0 == NULL)
103 		return got_error_from_errno("strdup");
104 	path = path0;
105 	pathlen = strlen(path);
106 
107 	/*
108 	 * Git clients send a shell command.
109 	 * Trim spaces and quotes around the path.
110 	 */
111 	while (path[0] == '\'' || path[0] == '\"' || path[0] == ' ') {
112 		path++;
113 		pathlen--;
114 	}
115 	while (pathlen > 0 &&
116 	    (path[pathlen - 1] == '\'' || path[pathlen - 1] == '\"' ||
117 	    path[pathlen - 1] == ' ')) {
118 		path[pathlen - 1] = '\0';
119 		pathlen--;
120 	}
121 
122 	/* Deny an empty repository path. */
123 	if (path[0] == '\0' || got_path_is_root_dir(path)) {
124 		err = got_error(GOT_ERR_NOT_GIT_REPO);
125 		goto done;
126 	}
127 
128 	if (asprintf(&abspath, "/%s", path) == -1) {
129 		err = got_error_from_errno("asprintf");
130 		goto done;
131 	}
132 	pathlen = strlen(abspath);
133 	canonpath = malloc(pathlen);
134 	if (canonpath == NULL) {
135 		err = got_error_from_errno("malloc");
136 		goto done;
137 	}
138 	err = got_canonpath(abspath, canonpath, pathlen);
139 	if (err)
140 		goto done;
141 
142 	relpath = canonpath;
143 	while (relpath[0] == '/')
144 		relpath++;
145 	*repo_path = strdup(relpath);
146 	if (*repo_path == NULL) {
147 		err = got_error_from_errno("strdup");
148 		goto done;
149 	}
150 	*command = strndup(gitcmd, cmdlen);
151 	if (*command == NULL)
152 		err = got_error_from_errno("strndup");
153 done:
154 	free(path0);
155 	free(abspath);
156 	free(canonpath);
157 	if (err) {
158 		free(*repo_path);
159 		*repo_path = NULL;
160 	}
161 	return err;
162 }
163 
164 static const struct got_error *
165 append_read_capabilities(size_t *capalen, size_t len, const char *symrefstr,
166     uint8_t *buf, size_t bufsize)
167 {
168 	struct got_capability capa[nitems(read_capabilities) + 1];
169 	size_t ncapa;
170 
171 	memcpy(&capa, read_capabilities, sizeof(read_capabilities));
172 	if (symrefstr) {
173 		capa[nitems(read_capabilities)].key = "symref";
174 		capa[nitems(read_capabilities)].value = symrefstr;
175 		ncapa = nitems(capa);
176 	} else
177 		ncapa = nitems(read_capabilities);
178 
179 	return got_gitproto_append_capabilities(capalen, buf, len,
180 	    bufsize, capa, ncapa);
181 }
182 
183 static const struct got_error *
184 send_ref(int outfd, uint8_t *id, const char *refname, int send_capabilities,
185     int client_is_reading, const char *symrefstr, int chattygot)
186 {
187 	const struct got_error *err = NULL;
188 	char hex[SHA1_DIGEST_STRING_LENGTH];
189 	char buf[GOT_PKT_MAX];
190 	size_t len, capalen = 0;
191 
192 	if (got_sha1_digest_to_str(id, hex, sizeof(hex)) == NULL)
193 		return got_error(GOT_ERR_BAD_OBJ_ID);
194 
195 	len = snprintf(buf, sizeof(buf), "%s %s", hex, refname);
196 	if (len >= sizeof(buf))
197 		return got_error(GOT_ERR_NO_SPACE);
198 
199 	if (send_capabilities) {
200 		if (client_is_reading) {
201 			err = append_read_capabilities(&capalen, len,
202 			    symrefstr, buf, sizeof(buf));
203 		} else {
204 			err = got_gitproto_append_capabilities(&capalen,
205 			    buf, len, sizeof(buf), write_capabilities,
206 			    nitems(write_capabilities));
207 		}
208 		if (err)
209 			return err;
210 		len += capalen;
211 	}
212 
213 	if (len + 1 >= sizeof(buf))
214 		return got_error(GOT_ERR_NO_SPACE);
215 	buf[len] = '\n';
216 	len++;
217 	buf[len] = '\0';
218 
219 	return got_pkt_writepkt(outfd, buf, len, chattygot);
220 }
221 
222 static const struct got_error *
223 send_zero_refs(int outfd, int client_is_reading, int chattygot)
224 {
225 	const struct got_error *err = NULL;
226 	char buf[GOT_PKT_MAX];
227 	uint8_t zero[SHA1_DIGEST_LENGTH];
228 	char hex[SHA1_DIGEST_STRING_LENGTH];
229 	size_t len, capalen = 0;
230 
231 	memset(&zero, 0, sizeof(zero));
232 
233 	if (got_sha1_digest_to_str(zero, hex, sizeof(hex)) == NULL)
234 		return got_error(GOT_ERR_BAD_OBJ_ID);
235 
236 	len = snprintf(buf, sizeof(buf), "%s capabilities^{}", hex);
237 	if (len >= sizeof(buf))
238 		return got_error(GOT_ERR_NO_SPACE);
239 
240 	if (client_is_reading) {
241 		err = got_gitproto_append_capabilities(&capalen, buf, len,
242 		    sizeof(buf), read_capabilities, nitems(read_capabilities));
243 		if (err)
244 			return err;
245 	} else {
246 		err = got_gitproto_append_capabilities(&capalen, buf, len,
247 		    sizeof(buf), write_capabilities,
248 		    nitems(write_capabilities));
249 		if (err)
250 			return err;
251 	}
252 
253 	return got_pkt_writepkt(outfd, buf, len + capalen, chattygot);
254 }
255 
256 static void
257 echo_error(const struct got_error *err, int outfd, int chattygot)
258 {
259 	char buf[4 + GOT_ERR_MAX_MSG_SIZE];
260 	size_t len;
261 
262 	/*
263 	 * Echo the error to the client on a pkt-line.
264 	 * The client should then terminate its session.
265 	 */
266 	buf[0] = 'E'; buf[1] = 'R'; buf[2] = 'R'; buf[3] = ' '; buf[4] = '\0';
267 	len = strlcat(buf, err->msg, sizeof(buf));
268 	got_pkt_writepkt(outfd, buf, len, chattygot);
269 }
270 
271 static const struct got_error *
272 announce_refs(int outfd, struct imsgbuf *ibuf, int client_is_reading,
273     const char *repo_path, int chattygot)
274 {
275 	const struct got_error *err = NULL;
276 	struct imsg imsg;
277 	size_t datalen;
278 	struct gotd_imsg_list_refs lsref;
279 	struct gotd_imsg_reflist ireflist;
280 	struct gotd_imsg_ref iref;
281 	struct gotd_imsg_symref isymref;
282 	size_t nrefs = 0;
283 	int have_nrefs = 0, sent_capabilities = 0;
284 	char *symrefname = NULL, *symreftarget = NULL, *symrefstr = NULL;
285 	char *refname = NULL;
286 
287 	memset(&imsg, 0, sizeof(imsg));
288 	memset(&lsref, 0, sizeof(lsref));
289 
290 	if (strlcpy(lsref.repo_name, repo_path, sizeof(lsref.repo_name)) >=
291 	    sizeof(lsref.repo_name))
292 		return got_error(GOT_ERR_NO_SPACE);
293 	lsref.client_is_reading = client_is_reading;
294 	
295 	if (imsg_compose(ibuf, GOTD_IMSG_LIST_REFS, 0, 0, -1,
296 	    &lsref, sizeof(lsref)) == -1)
297 		return got_error_from_errno("imsg_compose LIST_REFS");
298 
299 	err = gotd_imsg_flush(ibuf);
300 	if (err)
301 		return err;
302 
303 	while (!have_nrefs || nrefs > 0) {
304 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
305 		if (err)
306 			goto done;
307 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
308 		switch (imsg.hdr.type) {
309 		case GOTD_IMSG_ERROR:
310 			err = gotd_imsg_recv_error(NULL, &imsg);
311 			goto done;
312 		case GOTD_IMSG_REFLIST:
313 			if (have_nrefs || nrefs > 0) {
314 				err = got_error(GOT_ERR_PRIVSEP_MSG);
315 				goto done;
316 			}
317 			if (datalen != sizeof(ireflist)) {
318 				err = got_error(GOT_ERR_PRIVSEP_MSG);
319 				goto done;
320 			}
321 			memcpy(&ireflist, imsg.data, sizeof(ireflist));
322 			nrefs = ireflist.nrefs;
323 			have_nrefs = 1;
324 			if (nrefs == 0)
325 				err = send_zero_refs(outfd, client_is_reading,
326 				    chattygot);
327 			break;
328 		case GOTD_IMSG_REF:
329 			if (!have_nrefs || nrefs == 0) {
330 				err = got_error(GOT_ERR_PRIVSEP_MSG);
331 				goto done;
332 			}
333 			if (datalen < sizeof(iref)) {
334 				err = got_error(GOT_ERR_PRIVSEP_MSG);
335 				goto done;
336 			}
337 			memcpy(&iref, imsg.data, sizeof(iref));
338 			if (datalen != sizeof(iref) + iref.name_len) {
339 				err = got_error(GOT_ERR_PRIVSEP_LEN);
340 				goto done;
341 			}
342 			refname = malloc(iref.name_len + 1);
343 			if (refname == NULL) {
344 				err = got_error_from_errno("malloc");
345 				goto done;
346 			}
347 			memcpy(refname, imsg.data + sizeof(iref),
348 			    iref.name_len);
349 			refname[iref.name_len] = '\0';
350 			err = send_ref(outfd, iref.id, refname,
351 			    !sent_capabilities, client_is_reading,
352 			    NULL, chattygot);
353 			free(refname);
354 			refname = NULL;
355 			if (err)
356 				goto done;
357 			sent_capabilities = 1;
358 			if (nrefs > 0)
359 				nrefs--;
360 			break;
361 		case GOTD_IMSG_SYMREF:
362 			if (!have_nrefs || nrefs == 0) {
363 				err = got_error(GOT_ERR_PRIVSEP_MSG);
364 				goto done;
365 			}
366 			if (datalen < sizeof(isymref)) {
367 				err = got_error(GOT_ERR_PRIVSEP_LEN);
368 				goto done;
369 			}
370 			memcpy(&isymref, imsg.data, sizeof(isymref));
371 			if (datalen != sizeof(isymref) + isymref.name_len +
372 			    isymref.target_len) {
373 				err = got_error(GOT_ERR_PRIVSEP_LEN);
374 				goto done;
375 			}
376 
377 			/*
378 			 * For now, we only announce one symbolic ref,
379 			 * as part of our capability advertisement.
380 			 */
381 			if (sent_capabilities || symrefstr != NULL ||
382 			    symrefname != NULL || symreftarget != NULL)
383 				break;
384 
385 			symrefname = malloc(isymref.name_len + 1);
386 			if (symrefname == NULL) {
387 				err = got_error_from_errno("malloc");
388 				goto done;
389 			}
390 			memcpy(symrefname, imsg.data + sizeof(isymref),
391 			    isymref.name_len);
392 			symrefname[isymref.name_len] = '\0';
393 
394 			symreftarget = malloc(isymref.target_len + 1);
395 			if (symreftarget == NULL) {
396 				err = got_error_from_errno("malloc");
397 				goto done;
398 			}
399 			memcpy(symreftarget,
400 			    imsg.data + sizeof(isymref) + isymref.name_len,
401 			    isymref.target_len);
402 			symreftarget[isymref.target_len] = '\0';
403 
404 			if (asprintf(&symrefstr, "%s:%s", symrefname,
405 			    symreftarget) == -1) {
406 				err = got_error_from_errno("asprintf");
407 				goto done;
408 			}
409 			err = send_ref(outfd, isymref.target_id, symrefname,
410 			    !sent_capabilities, client_is_reading, symrefstr,
411 			    chattygot);
412 			free(refname);
413 			refname = NULL;
414 			if (err)
415 				goto done;
416 			sent_capabilities = 1;
417 			if (nrefs > 0)
418 				nrefs--;
419 			break;
420 		default:
421 			err = got_error(GOT_ERR_PRIVSEP_MSG);
422 			break;
423 		}
424 
425 		imsg_free(&imsg);
426 	}
427 
428 	err = got_pkt_flushpkt(outfd, chattygot);
429 	if (err)
430 		goto done;
431 done:
432 	free(symrefstr);
433 	free(symrefname);
434 	free(symreftarget);
435 	return err;
436 }
437 
438 static const struct got_error *
439 parse_want_line(char **common_capabilities, uint8_t *id, char *buf, size_t len)
440 {
441 	const struct got_error *err;
442 	char *id_str = NULL, *client_capabilities = NULL;
443 
444 	err = got_gitproto_parse_want_line(&id_str,
445 	    &client_capabilities, buf, len);
446 	if (err)
447 		return err;
448 
449 	if (!got_parse_sha1_digest(id, id_str)) {
450 		err = got_error_msg(GOT_ERR_BAD_PACKET,
451 		    "want-line with bad object ID");
452 		goto done;
453 	}
454 
455 	if (client_capabilities) {
456 		err = got_gitproto_match_capabilities(common_capabilities,
457 		    NULL, client_capabilities, read_capabilities,
458 		    nitems(read_capabilities));
459 		if (err)
460 			goto done;
461 	}
462 done:
463 	free(id_str);
464 	free(client_capabilities);
465 	return err;
466 }
467 
468 static const struct got_error *
469 parse_have_line(uint8_t *id, char *buf, size_t len)
470 {
471 	const struct got_error *err;
472 	char *id_str = NULL;
473 
474 	err = got_gitproto_parse_have_line(&id_str, buf, len);
475 	if (err)
476 		return err;
477 
478 	if (!got_parse_sha1_digest(id, id_str)) {
479 		err = got_error_msg(GOT_ERR_BAD_PACKET,
480 		    "have-line with bad object ID");
481 		goto done;
482 	}
483 done:
484 	free(id_str);
485 	return err;
486 }
487 
488 static const struct got_error *
489 send_capability(struct got_capability *capa, struct imsgbuf *ibuf)
490 {
491 	const struct got_error *err = NULL;
492 	struct gotd_imsg_capability icapa;
493 	size_t len;
494 	struct ibuf *wbuf;
495 
496 	memset(&icapa, 0, sizeof(icapa));
497 
498 	icapa.key_len = strlen(capa->key);
499 	len = sizeof(icapa) + icapa.key_len;
500 	if (capa->value) {
501 		icapa.value_len = strlen(capa->value);
502 		len += icapa.value_len;
503 	}
504 
505 	wbuf = imsg_create(ibuf, GOTD_IMSG_CAPABILITY, 0, 0, len);
506 	if (wbuf == NULL) {
507 		err = got_error_from_errno("imsg_create CAPABILITY");
508 		return err;
509 	}
510 
511 	if (imsg_add(wbuf, &icapa, sizeof(icapa)) == -1)
512 		return got_error_from_errno("imsg_add CAPABILITY");
513 	if (imsg_add(wbuf, capa->key, icapa.key_len) == -1)
514 		return got_error_from_errno("imsg_add CAPABILITY");
515 	if (capa->value) {
516 		if (imsg_add(wbuf, capa->value, icapa.value_len) == -1)
517 			return got_error_from_errno("imsg_add CAPABILITY");
518 	}
519 
520 	wbuf->fd = -1;
521 	imsg_close(ibuf, wbuf);
522 
523 	return NULL;
524 }
525 
526 static const struct got_error *
527 send_capabilities(int *use_sidebands, int *report_status,
528     char *capabilities_str, struct imsgbuf *ibuf)
529 {
530 	const struct got_error *err = NULL;
531 	struct gotd_imsg_capabilities icapas;
532 	struct got_capability *capa = NULL;
533 	size_t ncapa, i;
534 
535 	err = got_gitproto_split_capabilities_str(&capa, &ncapa,
536 	    capabilities_str);
537 	if (err)
538 		return err;
539 
540 	icapas.ncapabilities = ncapa;
541 	if (imsg_compose(ibuf, GOTD_IMSG_CAPABILITIES, 0, 0, -1,
542 	    &icapas, sizeof(icapas)) == -1) {
543 		err = got_error_from_errno("imsg_compose IMSG_CAPABILITIES");
544 		goto done;
545 	}
546 
547 	for (i = 0; i < ncapa; i++) {
548 		err = send_capability(&capa[i], ibuf);
549 		if (err)
550 			goto done;
551 		if (use_sidebands &&
552 		    strcmp(capa[i].key, GOT_CAPA_SIDE_BAND_64K) == 0)
553 			*use_sidebands = 1;
554 		if (report_status &&
555 		    strcmp(capa[i].key, GOT_CAPA_REPORT_STATUS) == 0)
556 			*report_status = 1;
557 	}
558 done:
559 	free(capa);
560 	return err;
561 }
562 
563 static const struct got_error *
564 forward_flushpkt(struct imsgbuf *ibuf)
565 {
566 	if (imsg_compose(ibuf, GOTD_IMSG_FLUSH, 0, 0, -1, NULL, 0) == -1)
567 		return got_error_from_errno("imsg_compose FLUSH");
568 
569 	return gotd_imsg_flush(ibuf);
570 }
571 
572 static const struct got_error *
573 recv_ack(struct imsg *imsg, uint8_t *expected_id)
574 {
575 	struct gotd_imsg_ack iack;
576 	size_t datalen;
577 
578 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
579 	if (datalen != sizeof(iack))
580 		return got_error(GOT_ERR_PRIVSEP_LEN);
581 
582 	memcpy(&iack, imsg->data, sizeof(iack));
583 	if (memcmp(iack.object_id, expected_id, SHA1_DIGEST_LENGTH) != 0)
584 		return got_error(GOT_ERR_BAD_OBJ_ID);
585 
586 	return NULL;
587 }
588 
589 static const struct got_error *
590 recv_nak(struct imsg *imsg, uint8_t *expected_id)
591 {
592 	struct gotd_imsg_ack inak;
593 	size_t datalen;
594 
595 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
596 	if (datalen != sizeof(inak))
597 		return got_error(GOT_ERR_PRIVSEP_LEN);
598 
599 	memcpy(&inak, imsg->data, sizeof(inak));
600 	if (memcmp(inak.object_id, expected_id, SHA1_DIGEST_LENGTH) != 0)
601 		return got_error(GOT_ERR_BAD_OBJ_ID);
602 
603 	return NULL;
604 }
605 
606 
607 static const struct got_error *
608 recv_want(int *use_sidebands, int outfd, struct imsgbuf *ibuf,
609     char *buf, size_t len, int expect_capabilities, int chattygot)
610 {
611 	const struct got_error *err;
612 	struct gotd_imsg_want iwant;
613 	char *capabilities_str;
614 	int done = 0;
615 	struct imsg imsg;
616 
617 	memset(&iwant, 0, sizeof(iwant));
618 	memset(&imsg, 0, sizeof(imsg));
619 
620 	err = parse_want_line(&capabilities_str, iwant.object_id, buf, len);
621 	if (err)
622 		return err;
623 
624 	if (capabilities_str) {
625 		if (!expect_capabilities) {
626 			err = got_error_msg(GOT_ERR_BAD_PACKET,
627 			    "unexpected capability announcement received");
628 			goto done;
629 		}
630 		err = send_capabilities(use_sidebands, NULL, capabilities_str,
631 		    ibuf);
632 		if (err)
633 			goto done;
634 
635 	}
636 
637 	if (imsg_compose(ibuf, GOTD_IMSG_WANT, 0, 0, -1,
638 	    &iwant, sizeof(iwant)) == -1) {
639 		err = got_error_from_errno("imsg_compose WANT");
640 		goto done;
641 	}
642 
643 	err = gotd_imsg_flush(ibuf);
644 	if (err)
645 		goto done;
646 
647 	/*
648 	 * Wait for an ACK, or an error in case the desired object
649 	 * does not exist.
650 	 */
651 	while (!done && err == NULL) {
652 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
653 		if (err)
654 			break;
655 		switch (imsg.hdr.type) {
656 		case GOTD_IMSG_ERROR:
657 			err = gotd_imsg_recv_error(NULL, &imsg);
658 			break;
659 		case GOTD_IMSG_ACK:
660 			err = recv_ack(&imsg, iwant.object_id);
661 			if (err)
662 				break;
663 			done = 1;
664 			break;
665 		default:
666 			err = got_error(GOT_ERR_PRIVSEP_MSG);
667 			break;
668 		}
669 
670 		imsg_free(&imsg);
671 	}
672 done:
673 	free(capabilities_str);
674 	return err;
675 }
676 
677 static const struct got_error *
678 send_ack(int outfd, uint8_t *id, int chattygot)
679 {
680 	char hex[SHA1_DIGEST_STRING_LENGTH];
681 	char buf[GOT_PKT_MAX];
682 	int len;
683 
684 	if (got_sha1_digest_to_str(id, hex, sizeof(hex)) == NULL)
685 		return got_error(GOT_ERR_BAD_OBJ_ID);
686 
687 	len = snprintf(buf, sizeof(buf), "ACK %s\n", hex);
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 send_nak(int outfd, int chattygot)
696 {
697 	char buf[5];
698 	int len;
699 
700 	len = snprintf(buf, sizeof(buf), "NAK\n");
701 	if (len >= sizeof(buf))
702 		return got_error(GOT_ERR_NO_SPACE);
703 
704 	return got_pkt_writepkt(outfd, buf, len, chattygot);
705 }
706 
707 static const struct got_error *
708 recv_have(int *have_ack, int outfd, struct imsgbuf *ibuf, char *buf,
709     size_t len, int chattygot)
710 {
711 	const struct got_error *err;
712 	struct gotd_imsg_have ihave;
713 	int done = 0;
714 	struct imsg imsg;
715 
716 	memset(&ihave, 0, sizeof(ihave));
717 	memset(&imsg, 0, sizeof(imsg));
718 
719 	err = parse_have_line(ihave.object_id, buf, len);
720 	if (err)
721 		return err;
722 
723 	if (imsg_compose(ibuf, GOTD_IMSG_HAVE, 0, 0, -1,
724 	    &ihave, sizeof(ihave)) == -1)
725 		return got_error_from_errno("imsg_compose HAVE");
726 
727 	err = gotd_imsg_flush(ibuf);
728 	if (err)
729 		return err;
730 
731 	/*
732 	 * Wait for an ACK or a NAK, indicating whether a common
733 	 * commit object has been found.
734 	 */
735 	while (!done && err == NULL) {
736 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
737 		if (err)
738 			return err;
739 		switch (imsg.hdr.type) {
740 		case GOTD_IMSG_ERROR:
741 			err = gotd_imsg_recv_error(NULL, &imsg);
742 			break;
743 		case GOTD_IMSG_ACK:
744 			err = recv_ack(&imsg, ihave.object_id);
745 			if (err)
746 				break;
747 			if (!*have_ack) {
748 				err = send_ack(outfd, ihave.object_id,
749 				    chattygot);
750 				if (err)
751 					return err;
752 				*have_ack = 1;
753 			}
754 			done = 1;
755 			break;
756 		case GOTD_IMSG_NAK:
757 			err = recv_nak(&imsg, ihave.object_id);
758 			if (err)
759 				break;
760 			done = 1;
761 			break;
762 		default:
763 			err = got_error(GOT_ERR_PRIVSEP_MSG);
764 			break;
765 		}
766 
767 		imsg_free(&imsg);
768 	}
769 
770 	return err;
771 }
772 
773 static const struct got_error *
774 recv_done(int *packfd, int outfd, struct imsgbuf *ibuf, int chattygot)
775 {
776 	const struct got_error *err;
777 	struct imsg imsg;
778 
779 	*packfd = -1;
780 
781 	if (imsg_compose(ibuf, GOTD_IMSG_DONE, 0, 0, -1, NULL, 0) == -1)
782 		return got_error_from_errno("imsg_compose DONE");
783 
784 	err = gotd_imsg_flush(ibuf);
785 	if (err)
786 		return err;
787 
788 	while (*packfd == -1 && err == NULL) {
789 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
790 		if (err)
791 			break;
792 
793 		switch (imsg.hdr.type) {
794 		case GOTD_IMSG_ERROR:
795 			err = gotd_imsg_recv_error(NULL, &imsg);
796 			break;
797 		case GOTD_IMSG_PACKFILE_PIPE:
798 			if (imsg.fd != -1)
799 				*packfd = imsg.fd;
800 			else
801 				err = got_error(GOT_ERR_PRIVSEP_NO_FD);
802 			break;
803 		default:
804 			err = got_error(GOT_ERR_PRIVSEP_MSG);
805 			break;
806 		}
807 
808 		imsg_free(&imsg);
809 	}
810 
811 	return err;
812 }
813 
814 static const struct got_error *
815 relay_progress_reports(struct imsgbuf *ibuf, int outfd, int chattygot)
816 {
817 	const struct got_error *err = NULL;
818 	int pack_starting = 0;
819 	struct gotd_imsg_packfile_progress iprog;
820 	char buf[GOT_PKT_MAX];
821 	struct imsg imsg;
822 	size_t datalen;
823 	int p_deltify = 0, n;
824 	const char *eol = "\r";
825 
826 	memset(&imsg, 0, sizeof(imsg));
827 
828 	while (!pack_starting && err == NULL) {
829 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
830 		if (err)
831 			break;
832 
833 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
834 		switch (imsg.hdr.type) {
835 		case GOTD_IMSG_ERROR:
836 			err = gotd_imsg_recv_error(NULL, &imsg);
837 			break;
838 		case GOTD_IMSG_PACKFILE_READY:
839 			eol = "\n";
840 			pack_starting = 1;
841 			/* fallthrough */
842 		case GOTD_IMSG_PACKFILE_PROGRESS:
843 			if (datalen != sizeof(iprog)) {
844 				err = got_error(GOT_ERR_PRIVSEP_LEN);
845 				break;
846 			}
847 			memcpy(&iprog, imsg.data, sizeof(iprog));
848 			if (iprog.nobj_total > 0) {
849 				p_deltify = (iprog.nobj_deltify * 100) /
850 				    iprog.nobj_total;
851 			}
852 			buf[0] = GOT_SIDEBAND_PROGRESS_INFO;
853 			n = snprintf(&buf[1], sizeof(buf) - 1,
854 			    "%d commits colored, "
855 			    "%d objects found, "
856 			    "deltify %d%%%s",
857 			    iprog.ncolored,
858 			    iprog.nfound,
859 			    p_deltify, eol);
860 			if (n >= sizeof(buf) - 1)
861 				break;
862 			err = got_pkt_writepkt(outfd, buf, 1 + n, chattygot);
863 			break;
864 		default:
865 			err = got_error(GOT_ERR_PRIVSEP_MSG);
866 			break;
867 		}
868 
869 		imsg_free(&imsg);
870 	}
871 
872 	return err;
873 }
874 
875 static const struct got_error *
876 serve_read(int infd, int outfd, int gotd_sock, const char *repo_path,
877     int chattygot)
878 {
879 	const struct got_error *err = NULL;
880 	char buf[GOT_PKT_MAX];
881 	struct imsgbuf ibuf;
882 	enum protostate {
883 		STATE_EXPECT_WANT,
884 		STATE_EXPECT_MORE_WANT,
885 		STATE_EXPECT_HAVE,
886 		STATE_EXPECT_DONE,
887 		STATE_DONE,
888 	};
889 	enum protostate curstate = STATE_EXPECT_WANT;
890 	int have_ack = 0, use_sidebands = 0, seen_have = 0;
891 	int packfd = -1;
892 	size_t pack_chunksize;
893 
894 	imsg_init(&ibuf, gotd_sock);
895 
896 	err = announce_refs(outfd, &ibuf, 1, repo_path, chattygot);
897 	if (err)
898 		goto done;
899 
900 	while (curstate != STATE_DONE) {
901 		int n;
902 		buf[0] = '\0';
903 		err = got_pkt_readpkt(&n, infd, buf, sizeof(buf), chattygot);
904 		if (err)
905 			break;
906 		if (n == 0) {
907 			if (curstate != STATE_EXPECT_MORE_WANT &&
908 			    curstate != STATE_EXPECT_HAVE) {
909 				err = got_error_msg(GOT_ERR_BAD_PACKET,
910 				    "unexpected flush packet received");
911 				goto done;
912 			}
913 			err = forward_flushpkt(&ibuf);
914 			if (err)
915 				goto done;
916 			if (curstate == STATE_EXPECT_HAVE && !have_ack) {
917 				err = send_nak(outfd, chattygot);
918 				if (err)
919 					goto done;
920 			}
921 			if (curstate == STATE_EXPECT_MORE_WANT)
922 				curstate = STATE_EXPECT_HAVE;
923 			else
924 				curstate = STATE_EXPECT_DONE;
925 		} else if (n >= 5 && strncmp(buf, "want ", 5) == 0) {
926 			if (curstate != STATE_EXPECT_WANT &&
927 			    curstate != STATE_EXPECT_MORE_WANT) {
928 				err = got_error_msg(GOT_ERR_BAD_PACKET,
929 				    "unexpected 'want' packet");
930 				goto done;
931 			}
932 			err = recv_want(&use_sidebands, outfd, &ibuf, buf, n,
933 			    curstate == STATE_EXPECT_WANT ? 1 : 0, chattygot);
934 			if (err)
935 				goto done;
936 			if (curstate == STATE_EXPECT_WANT)
937 				curstate = STATE_EXPECT_MORE_WANT;
938 		} else if (n >= 5 && strncmp(buf, "have ", 5) == 0) {
939 			if (curstate != STATE_EXPECT_HAVE) {
940 				err = got_error_msg(GOT_ERR_BAD_PACKET,
941 				    "unexpected 'have' packet");
942 				goto done;
943 			}
944 			err = recv_have(&have_ack, outfd, &ibuf, buf, n,
945 			    chattygot);
946 			if (err)
947 				goto done;
948 			seen_have = 1;
949 		} else if (n == 5 && strncmp(buf, "done\n", 5) == 0) {
950 			if (curstate != STATE_EXPECT_HAVE &&
951 			    curstate != STATE_EXPECT_DONE) {
952 				err = got_error_msg(GOT_ERR_BAD_PACKET,
953 				    "unexpected 'done' packet");
954 				goto done;
955 			}
956 			err = recv_done(&packfd, outfd, &ibuf, chattygot);
957 			if (err)
958 				goto done;
959 			curstate = STATE_DONE;
960 			break;
961 		} else {
962 			err = got_error(GOT_ERR_BAD_PACKET);
963 			goto done;
964 		}
965 	}
966 
967 	if (!seen_have) {
968 		err = send_nak(outfd, chattygot);
969 		if (err)
970 			goto done;
971 	}
972 
973 	if (use_sidebands) {
974 		err = relay_progress_reports(&ibuf, outfd, chattygot);
975 		if (err)
976 			goto done;
977 		pack_chunksize = GOT_SIDEBAND_64K_PACKFILE_DATA_MAX;
978 	} else
979 		pack_chunksize = sizeof(buf);
980 
981 	for (;;) {
982 		ssize_t r;
983 
984 		r = read(packfd, use_sidebands ? &buf[1] : buf,
985 		    pack_chunksize);
986 		if (r == -1) {
987 			err = got_error_from_errno("read");
988 			break;
989 		} else if (r == 0) {
990 			err = got_pkt_flushpkt(outfd, chattygot);
991 			break;
992 		}
993 
994 		if (use_sidebands) {
995 			buf[0] = GOT_SIDEBAND_PACKFILE_DATA;
996 			err = got_pkt_writepkt(outfd, buf, 1 + r, chattygot);
997 			if (err)
998 				break;
999 		} else {
1000 			err = got_poll_write_full(outfd, buf, r);
1001 			if (err) {
1002 				if (err->code == GOT_ERR_EOF)
1003 					err = NULL;
1004 				break;
1005 			}
1006 		}
1007 	}
1008 done:
1009 	imsg_clear(&ibuf);
1010 	if (packfd != -1 && close(packfd) == -1 && err == NULL)
1011 		err = got_error_from_errno("close");
1012 	if (err)
1013 		echo_error(err, outfd, chattygot);
1014 	return err;
1015 }
1016 
1017 static const struct got_error *
1018 parse_ref_update_line(char **common_capabilities, char **refname,
1019     uint8_t *old_id, uint8_t *new_id, char *buf, size_t len)
1020 {
1021 	const struct got_error *err;
1022 	char *old_id_str = NULL, *new_id_str = NULL;
1023 	char *client_capabilities = NULL;
1024 
1025 	*refname = NULL;
1026 
1027 	err = got_gitproto_parse_ref_update_line(&old_id_str, &new_id_str,
1028 	    refname, &client_capabilities, buf, len);
1029 	if (err)
1030 		return err;
1031 
1032 	if (!got_parse_sha1_digest(old_id, old_id_str) ||
1033 	    !got_parse_sha1_digest(new_id, new_id_str)) {
1034 		err = got_error_msg(GOT_ERR_BAD_PACKET,
1035 		    "ref-update with bad object ID");
1036 		goto done;
1037 	}
1038 	if (!got_ref_name_is_valid(*refname)) {
1039 		err = got_error_msg(GOT_ERR_BAD_PACKET,
1040 		    "ref-update with bad reference name");
1041 		goto done;
1042 	}
1043 
1044 	if (client_capabilities) {
1045 		err = got_gitproto_match_capabilities(common_capabilities,
1046 		    NULL, client_capabilities, write_capabilities,
1047 		    nitems(write_capabilities));
1048 		if (err)
1049 			goto done;
1050 	}
1051 done:
1052 	free(old_id_str);
1053 	free(new_id_str);
1054 	free(client_capabilities);
1055 	if (err) {
1056 		free(*refname);
1057 		*refname = NULL;
1058 	}
1059 	return err;
1060 }
1061 
1062 static const struct got_error *
1063 recv_ref_update(int *report_status, int outfd, struct imsgbuf *ibuf,
1064     char *buf, size_t len, int expect_capabilities, int chattygot)
1065 {
1066 	const struct got_error *err;
1067 	struct gotd_imsg_ref_update iref;
1068 	struct ibuf *wbuf;
1069 	char *capabilities_str = NULL, *refname = NULL;
1070 	int done = 0;
1071 	struct imsg imsg;
1072 
1073 	memset(&iref, 0, sizeof(iref));
1074 	memset(&imsg, 0, sizeof(imsg));
1075 
1076 	err = parse_ref_update_line(&capabilities_str, &refname,
1077 	    iref.old_id, iref.new_id, buf, len);
1078 	if (err)
1079 		return err;
1080 
1081 	if (capabilities_str) {
1082 		if (!expect_capabilities) {
1083 			err = got_error_msg(GOT_ERR_BAD_PACKET,
1084 			    "unexpected capability announcement received");
1085 			goto done;
1086 		}
1087 		err = send_capabilities(NULL, report_status, capabilities_str,
1088 		    ibuf);
1089 		if (err)
1090 			goto done;
1091 	}
1092 
1093 	iref.name_len = strlen(refname);
1094 	len = sizeof(iref) + iref.name_len;
1095 	wbuf = imsg_create(ibuf, GOTD_IMSG_REF_UPDATE, 0, 0, len);
1096 	if (wbuf == NULL) {
1097 		err = got_error_from_errno("imsg_create REF_UPDATE");
1098 		goto done;
1099 	}
1100 
1101 	if (imsg_add(wbuf, &iref, sizeof(iref)) == -1)
1102 		return got_error_from_errno("imsg_add REF_UPDATE");
1103 	if (imsg_add(wbuf, refname, iref.name_len) == -1)
1104 		return got_error_from_errno("imsg_add REF_UPDATE");
1105 	wbuf->fd = -1;
1106 	imsg_close(ibuf, wbuf);
1107 
1108 	err = gotd_imsg_flush(ibuf);
1109 	if (err)
1110 		goto done;
1111 
1112 	/* Wait for ACK or an error. */
1113 	while (!done && err == NULL) {
1114 		err = gotd_imsg_poll_recv(&imsg, ibuf, 0);
1115 		if (err)
1116 			break;
1117 		switch (imsg.hdr.type) {
1118 		case GOTD_IMSG_ERROR:
1119 			err = gotd_imsg_recv_error(NULL, &imsg);
1120 			break;
1121 		case GOTD_IMSG_ACK:
1122 			err = recv_ack(&imsg, iref.new_id);
1123 			if (err)
1124 				break;
1125 			done = 1;
1126 			break;
1127 		default:
1128 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1129 			break;
1130 		}
1131 
1132 		imsg_free(&imsg);
1133 	}
1134 done:
1135 	free(capabilities_str);
1136 	free(refname);
1137 	return err;
1138 }
1139 
1140 static const struct got_error *
1141 recv_packfile(struct imsg *imsg, int infd)
1142 {
1143 	const struct got_error *err = NULL;
1144 	size_t datalen;
1145 	int packfd;
1146 	char buf[GOT_PKT_MAX];
1147 	int pack_done = 0;
1148 
1149 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1150 	if (datalen != 0)
1151 		return got_error(GOT_ERR_PRIVSEP_MSG);
1152 
1153 	if (imsg->fd == -1)
1154 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
1155 	
1156 	packfd = imsg->fd;
1157 	while (!pack_done) {
1158 		ssize_t r = 0;
1159 
1160 		err = got_poll_fd(infd, POLLIN, 1);
1161 		if (err) {
1162 			if (err->code != GOT_ERR_TIMEOUT)
1163 				break;
1164 			err = NULL;
1165 		} else {
1166 			r = read(infd, buf, sizeof(buf));
1167 			if (r == -1) {
1168 				err = got_error_from_errno("read");
1169 				break;
1170 			}
1171 			if (r == 0) {
1172 				/*
1173 				 * Git clients hang up their side of the
1174 				 * connection after sending the pack file.
1175 				 */
1176 				err = NULL;
1177 				pack_done = 1;
1178 				break;
1179 			}
1180 		}
1181 
1182 		if (r == 0) {
1183 			/* Detect gotd(8) closing the pack pipe when done. */
1184 			err = got_poll_fd(packfd, POLLOUT, 1);
1185 			if (err) {
1186 				if (err->code != GOT_ERR_EOF)
1187 					break;
1188 				err = NULL;
1189 				pack_done = 1;
1190 			}
1191 		} else {
1192 			/* Write pack data and/or detect pipe being closed. */
1193 			err = got_poll_write_full(packfd, buf, r);
1194 			if (err) {
1195 				if (err->code == GOT_ERR_EOF)
1196 					err = NULL;
1197 				break;
1198 			}
1199 		}
1200 	}
1201 
1202 	close(packfd);
1203 	return err;
1204 }
1205 
1206 static const struct got_error *
1207 report_unpack_status(struct imsg *imsg, int outfd, int chattygot)
1208 {
1209 	const struct got_error *err = NULL;
1210 	struct gotd_imsg_packfile_status istatus;
1211 	char buf[GOT_PKT_MAX];
1212 	size_t datalen, len;
1213 	char *reason = NULL;
1214 
1215 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1216 	if (datalen < sizeof(istatus))
1217 		return got_error(GOT_ERR_PRIVSEP_LEN);
1218 	memcpy(&istatus, imsg->data, sizeof(istatus));
1219 	if (datalen != sizeof(istatus) + istatus.reason_len)
1220 		return got_error(GOT_ERR_PRIVSEP_LEN);
1221 
1222 	reason = malloc(istatus.reason_len + 1);
1223 	if (reason == NULL) {
1224 		err = got_error_from_errno("malloc");
1225 		goto done;
1226 	}
1227 	memcpy(reason, imsg->data + sizeof(istatus), istatus.reason_len);
1228 	reason[istatus.reason_len] = '\0';
1229 
1230 	if (err == NULL)
1231 		len = snprintf(buf, sizeof(buf), "unpack ok\n");
1232 	else
1233 		len = snprintf(buf, sizeof(buf), "unpack %s\n", reason);
1234 	if (len >= sizeof(buf)) {
1235 		err = got_error(GOT_ERR_NO_SPACE);
1236 		goto done;
1237 	}
1238 
1239 	err = got_pkt_writepkt(outfd, buf, len, chattygot);
1240 done:
1241 	free(reason);
1242 	return err;
1243 }
1244 
1245 static const struct got_error *
1246 recv_ref_update_ok(struct imsg *imsg, int outfd, int chattygot)
1247 {
1248 	const struct got_error *err = NULL;
1249 	struct gotd_imsg_ref_update_ok iok;
1250 	size_t datalen, len;
1251 	char buf[GOT_PKT_MAX];
1252 	char *refname = NULL;
1253 
1254 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1255 	if (datalen < sizeof(iok))
1256 		return got_error(GOT_ERR_PRIVSEP_LEN);
1257 	memcpy(&iok, imsg->data, sizeof(iok));
1258 	if (datalen != sizeof(iok) + iok.name_len)
1259 		return got_error(GOT_ERR_PRIVSEP_LEN);
1260 
1261 	memcpy(&iok, imsg->data, sizeof(iok));
1262 
1263 	refname = malloc(iok.name_len + 1);
1264 	if (refname == NULL)
1265 		return got_error_from_errno("malloc");
1266 	memcpy(refname, imsg->data + sizeof(iok), iok.name_len);
1267 	refname[iok.name_len] = '\0';
1268 
1269 	len = snprintf(buf, sizeof(buf), "ok %s\n", refname);
1270 	if (len >= sizeof(buf)) {
1271 		err = got_error(GOT_ERR_NO_SPACE);
1272 		goto done;
1273 	}
1274 
1275 	err = got_pkt_writepkt(outfd, buf, len, chattygot);
1276 done:
1277 	free(refname);
1278 	return err;
1279 }
1280 
1281 static const struct got_error *
1282 recv_ref_update_ng(struct imsg *imsg, int outfd, int chattygot)
1283 {
1284 	const struct got_error *err = NULL;
1285 	struct gotd_imsg_ref_update_ng ing;
1286 	size_t datalen, len;
1287 	char buf[GOT_PKT_MAX];
1288 	char *refname = NULL, *reason = NULL;
1289 
1290 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1291 	if (datalen < sizeof(ing))
1292 		return got_error(GOT_ERR_PRIVSEP_LEN);
1293 	memcpy(&ing, imsg->data, sizeof(ing));
1294 	if (datalen != sizeof(ing) + ing.name_len + ing.reason_len)
1295 		return got_error(GOT_ERR_PRIVSEP_LEN);
1296 
1297 	memcpy(&ing, imsg->data, sizeof(ing));
1298 
1299 	refname = malloc(ing.name_len + 1);
1300 	if (refname == NULL)
1301 		return got_error_from_errno("malloc");
1302 	memcpy(refname, imsg->data + sizeof(ing), ing.name_len);
1303 	refname[ing.name_len] = '\0';
1304 
1305 	reason = malloc(ing.reason_len + 1);
1306 	if (reason == NULL) {
1307 		err = got_error_from_errno("malloc");
1308 		goto done;
1309 	}
1310 	memcpy(refname, imsg->data + sizeof(ing) + ing.name_len,
1311 	    ing.reason_len);
1312 	refname[ing.reason_len] = '\0';
1313 
1314 	len = snprintf(buf, sizeof(buf), "ng %s %s\n", refname, reason);
1315 	if (len >= sizeof(buf)) {
1316 		err = got_error(GOT_ERR_NO_SPACE);
1317 		goto done;
1318 	}
1319 
1320 	err = got_pkt_writepkt(outfd, buf, len, chattygot);
1321 done:
1322 	free(refname);
1323 	free(reason);
1324 	return err;
1325 }
1326 
1327 static const struct got_error *
1328 serve_write(int infd, int outfd, int gotd_sock, const char *repo_path,
1329     int chattygot)
1330 {
1331 	const struct got_error *err = NULL;
1332 	char buf[GOT_PKT_MAX];
1333 	struct imsgbuf ibuf;
1334 	enum protostate {
1335 		STATE_EXPECT_REF_UPDATE,
1336 		STATE_EXPECT_MORE_REF_UPDATES,
1337 		STATE_EXPECT_PACKFILE,
1338 		STATE_PACKFILE_RECEIVED,
1339 		STATE_REFS_UPDATED,
1340 	};
1341 	enum protostate curstate = STATE_EXPECT_REF_UPDATE;
1342 	struct imsg imsg;
1343 	int report_status = 0;
1344 
1345 	imsg_init(&ibuf, gotd_sock);
1346 	memset(&imsg, 0, sizeof(imsg));
1347 
1348 	err = announce_refs(outfd, &ibuf, 0, repo_path, chattygot);
1349 	if (err)
1350 		goto done;
1351 
1352 	while (curstate != STATE_EXPECT_PACKFILE) {
1353 		int n;
1354 		buf[0] = '\0';
1355 		err = got_pkt_readpkt(&n, infd, buf, sizeof(buf), chattygot);
1356 		if (err)
1357 			break;
1358 		if (n == 0) {
1359 			if (curstate != STATE_EXPECT_MORE_REF_UPDATES) {
1360 				err = got_error_msg(GOT_ERR_BAD_PACKET,
1361 				    "unexpected flush packet received");
1362 				goto done;
1363 			}
1364 			err = forward_flushpkt(&ibuf);
1365 			if (err)
1366 				goto done;
1367 			curstate = STATE_EXPECT_PACKFILE;
1368 		} else if (n >= (SHA1_DIGEST_STRING_LENGTH * 2) + 2) {
1369 			if (curstate != STATE_EXPECT_REF_UPDATE &&
1370 			    curstate != STATE_EXPECT_MORE_REF_UPDATES) {
1371 				err = got_error_msg(GOT_ERR_BAD_PACKET,
1372 				    "unexpected ref-update packet");
1373 				goto done;
1374 			}
1375 			if (curstate == STATE_EXPECT_REF_UPDATE) {
1376 				err = recv_ref_update(&report_status,
1377 				    outfd, &ibuf, buf, n, 1, chattygot);
1378 			} else {
1379 				err = recv_ref_update(NULL, outfd, &ibuf,
1380 				    buf, n, 0, chattygot);
1381 			}
1382 			if (err)
1383 				goto done;
1384 			curstate = STATE_EXPECT_MORE_REF_UPDATES;
1385 		} else {
1386 			err = got_error(GOT_ERR_BAD_PACKET);
1387 			goto done;
1388 		}
1389 	}
1390 
1391 	while (curstate != STATE_PACKFILE_RECEIVED) {
1392 		err = gotd_imsg_poll_recv(&imsg, &ibuf, 0);
1393 		if (err)
1394 			goto done;
1395 		switch (imsg.hdr.type) {
1396 		case GOTD_IMSG_ERROR:
1397 			err = gotd_imsg_recv_error(NULL, &imsg);
1398 			goto done;
1399 		case GOTD_IMSG_PACKFILE_PIPE:
1400 			err = recv_packfile(&imsg, infd);
1401 			if (err) {
1402 				if (err->code != GOT_ERR_EOF)
1403 					goto done;
1404 				/*
1405 				 * EOF is reported when the client hangs up,
1406 				 * which can happen with Git clients.
1407 				 * The socket should stay half-open so we
1408 				 * can still send our reports if requested.
1409 				 */
1410 				err = NULL;
1411 			}
1412 			curstate = STATE_PACKFILE_RECEIVED;
1413 			break;
1414 		default:
1415 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1416 			break;
1417 		}
1418 
1419 		imsg_free(&imsg);
1420 		if (err)
1421 			goto done;
1422 	}
1423 
1424 	while (curstate != STATE_REFS_UPDATED && err == NULL) {
1425 		err = gotd_imsg_poll_recv(&imsg, &ibuf, 0);
1426 		if (err)
1427 			break;
1428 		switch (imsg.hdr.type) {
1429 		case GOTD_IMSG_ERROR:
1430 			err = gotd_imsg_recv_error(NULL, &imsg);
1431 			break;
1432 		case GOTD_IMSG_PACKFILE_STATUS:
1433 			if (!report_status)
1434 				break;
1435 			err = report_unpack_status(&imsg, outfd, chattygot);
1436 			break;
1437 		case GOTD_IMSG_REF_UPDATE_OK:
1438 			if (!report_status)
1439 				break;
1440 			err = recv_ref_update_ok(&imsg, outfd, chattygot);
1441 			break;
1442 		case GOTD_IMSG_REF_UPDATE_NG:
1443 			if (!report_status)
1444 				break;
1445 			err = recv_ref_update_ng(&imsg, outfd, chattygot);
1446 			break;
1447 		case GOTD_IMSG_REFS_UPDATED:
1448 			curstate = STATE_REFS_UPDATED;
1449 			err = got_pkt_flushpkt(outfd, chattygot);
1450 			break;
1451 		default:
1452 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1453 			break;
1454 		}
1455 
1456 		imsg_free(&imsg);
1457 	}
1458 done:
1459 	imsg_clear(&ibuf);
1460 	if (err)
1461 		echo_error(err, outfd, chattygot);
1462 	return err;
1463 }
1464 
1465 const struct got_error *
1466 got_serve(int infd, int outfd, const char *gitcmd, int gotd_sock, int chattygot)
1467 {
1468 	const struct got_error *err = NULL;
1469 	char *command = NULL, *repo_path = NULL;
1470 
1471 	err = parse_command(&command, &repo_path, gitcmd);
1472 	if (err)
1473 		return err;
1474 
1475 	if (strcmp(command, GOT_SERVE_CMD_FETCH) == 0)
1476 		err = serve_read(infd, outfd, gotd_sock, repo_path, chattygot);
1477 	else if (strcmp(command, GOT_SERVE_CMD_SEND) == 0)
1478 		err = serve_write(infd, outfd, gotd_sock, repo_path, chattygot);
1479 	else
1480 		err = got_error(GOT_ERR_BAD_PACKET);
1481 
1482 	free(command);
1483 	free(repo_path);
1484 	return err;
1485 }