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Date:: Tue Apr 4 21:15:49 2023 UTC
Message:: add support for protecting references against 'got send -f' to gotd ok op@
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1 /*
2  * Copyright (c) 2022 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <sys/queue.h>
18 #include <sys/types.h>
19 
20 #include <event.h>
21 #include <errno.h>
22 #include <imsg.h>
23 #include <signal.h>
24 #include <stdlib.h>
25 #include <limits.h>
26 #include <poll.h>
27 #include <siphash.h>
28 #include <stdio.h>
29 #include <string.h>
30 #include <unistd.h>
31 
32 #include "got_error.h"
33 #include "got_cancel.h"
34 #include "got_object.h"
35 #include "got_repository.h"
36 #include "got_reference.h"
37 #include "got_repository_admin.h"
38 #include "got_path.h"
39 
40 #include "got_lib_delta.h"
41 #include "got_lib_object.h"
42 #include "got_lib_object_idset.h"
43 #include "got_lib_hash.h"
44 #include "got_lib_pack.h"
45 #include "got_lib_ratelimit.h"
46 #include "got_lib_pack_create.h"
47 #include "got_lib_poll.h"
48 
49 #include "log.h"
50 #include "gotd.h"
51 #include "repo_read.h"
52 
53 #ifndef nitems
54 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
55 #endif
56 
57 static struct repo_read {
58 	pid_t pid;
59 	const char *title;
60 	struct got_repository *repo;
61 	int *pack_fds;
62 	int *temp_fds;
63 	int session_fd;
64 	struct gotd_imsgev session_iev;
65 } repo_read;
66 
67 static struct repo_read_client {
68 	uint32_t			 id;
69 	int				 fd;
70 	int				 delta_cache_fd;
71 	int				 report_progress;
72 	int				 pack_pipe;
73 	struct got_object_idset		*want_ids;
74 	struct got_object_idset		*have_ids;
75 } repo_read_client;
76 
77 static volatile sig_atomic_t sigint_received;
78 static volatile sig_atomic_t sigterm_received;
79 
80 static void
81 catch_sigint(int signo)
82 {
83 	sigint_received = 1;
84 }
85 
86 static void
87 catch_sigterm(int signo)
88 {
89 	sigterm_received = 1;
90 }
91 
92 static const struct got_error *
93 check_cancelled(void *arg)
94 {
95 	if (sigint_received || sigterm_received)
96 		return got_error(GOT_ERR_CANCELLED);
97 
98 	return NULL;
99 }
100 
101 static const struct got_error *
102 send_symref(struct got_reference *symref, struct got_object_id *target_id,
103     struct imsgbuf *ibuf)
104 {
105 	const struct got_error *err = NULL;
106 	struct gotd_imsg_symref isymref;
107 	const char *refname = got_ref_get_name(symref);
108 	const char *target = got_ref_get_symref_target(symref);
109 	size_t len;
110 	struct ibuf *wbuf;
111 
112 	memset(&isymref, 0, sizeof(isymref));
113 	isymref.name_len = strlen(refname);
114 	isymref.target_len = strlen(target);
115 	memcpy(isymref.target_id, target_id->sha1, sizeof(isymref.target_id));
116 
117 	len = sizeof(isymref) + isymref.name_len + isymref.target_len;
118 	if (len > MAX_IMSGSIZE - IMSG_HEADER_SIZE) {
119 		err = got_error(GOT_ERR_NO_SPACE);
120 		goto done;
121 	}
122 
123 	wbuf = imsg_create(ibuf, GOTD_IMSG_SYMREF, 0, 0, len);
124 	if (wbuf == NULL) {
125 		err = got_error_from_errno("imsg_create SYMREF");
126 		goto done;
127 	}
128 
129 	if (imsg_add(wbuf, &isymref, sizeof(isymref)) == -1) {
130 		err = got_error_from_errno("imsg_add SYMREF");
131 		goto done;
132 	}
133 	if (imsg_add(wbuf, refname, isymref.name_len) == -1) {
134 		err = got_error_from_errno("imsg_add SYMREF");
135 		goto done;
136 	}
137 	if (imsg_add(wbuf, target, isymref.target_len) == -1) {
138 		err = got_error_from_errno("imsg_add SYMREF");
139 		goto done;
140 	}
141 
142 	wbuf->fd = -1;
143 	imsg_close(ibuf, wbuf);
144 done:
145 	free(target_id);
146 	return err;
147 }
148 
149 static const struct got_error *
150 send_peeled_tag_ref(struct got_reference *ref, struct got_object *obj,
151     struct imsgbuf *ibuf)
152 {
153 	const struct got_error *err = NULL;
154 	struct got_tag_object *tag;
155 	size_t namelen, len;
156 	char *peeled_refname = NULL;
157 	struct got_object_id *id;
158 	struct ibuf *wbuf;
159 
160 	err = got_object_tag_open(&tag, repo_read.repo, obj);
161 	if (err)
162 		return err;
163 
164 	if (asprintf(&peeled_refname, "%s^{}", got_ref_get_name(ref)) == -1) {
165 		err = got_error_from_errno("asprintf");
166 		goto done;
167 	}
168 
169 	id = got_object_tag_get_object_id(tag);
170 	namelen = strlen(peeled_refname);
171 
172 	len = sizeof(struct gotd_imsg_ref) + namelen;
173 	if (len > MAX_IMSGSIZE - IMSG_HEADER_SIZE) {
174 		err = got_error(GOT_ERR_NO_SPACE);
175 		goto done;
176 	}
177 
178 	wbuf = imsg_create(ibuf, GOTD_IMSG_REF, PROC_REPO_READ,
179 	    repo_read.pid, len);
180 	if (wbuf == NULL) {
181 		err = got_error_from_errno("imsg_create MREF");
182 		goto done;
183 	}
184 
185 	/* Keep in sync with struct gotd_imsg_ref definition. */
186 	if (imsg_add(wbuf, id->sha1, SHA1_DIGEST_LENGTH) == -1) {
187 		err = got_error_from_errno("imsg_add REF");
188 		goto done;
189 	}
190 	if (imsg_add(wbuf, &namelen, sizeof(namelen)) == -1) {
191 		err = got_error_from_errno("imsg_add REF");
192 		goto done;
193 	}
194 	if (imsg_add(wbuf, peeled_refname, namelen) == -1) {
195 		err = got_error_from_errno("imsg_add REF");
196 		goto done;
197 	}
198 
199 	wbuf->fd = -1;
200 	imsg_close(ibuf, wbuf);
201 done:
202 	got_object_tag_close(tag);
203 	return err;
204 }
205 
206 static const struct got_error *
207 send_ref(struct got_reference *ref, struct imsgbuf *ibuf)
208 {
209 	const struct got_error *err;
210 	const char *refname = got_ref_get_name(ref);
211 	size_t namelen;
212 	struct got_object_id *id = NULL;
213 	struct got_object *obj = NULL;
214 	size_t len;
215 	struct ibuf *wbuf;
216 
217 	namelen = strlen(refname);
218 
219 	len = sizeof(struct gotd_imsg_ref) + namelen;
220 	if (len > MAX_IMSGSIZE - IMSG_HEADER_SIZE)
221 		return got_error(GOT_ERR_NO_SPACE);
222 
223 	err = got_ref_resolve(&id, repo_read.repo, ref);
224 	if (err)
225 		return err;
226 
227 	wbuf = imsg_create(ibuf, GOTD_IMSG_REF, PROC_REPO_READ,
228 	    repo_read.pid, len);
229 	if (wbuf == NULL) {
230 		err = got_error_from_errno("imsg_create REF");
231 		goto done;
232 	}
233 
234 	/* Keep in sync with struct gotd_imsg_ref definition. */
235 	if (imsg_add(wbuf, id->sha1, SHA1_DIGEST_LENGTH) == -1)
236 		return got_error_from_errno("imsg_add REF");
237 	if (imsg_add(wbuf, &namelen, sizeof(namelen)) == -1)
238 		return got_error_from_errno("imsg_add REF");
239 	if (imsg_add(wbuf, refname, namelen) == -1)
240 		return got_error_from_errno("imsg_add REF");
241 
242 	wbuf->fd = -1;
243 	imsg_close(ibuf, wbuf);
244 
245 	err = got_object_open(&obj, repo_read.repo, id);
246 	if (err)
247 		goto done;
248 	if (obj->type == GOT_OBJ_TYPE_TAG)
249 		err = send_peeled_tag_ref(ref, obj, ibuf);
250 done:
251 	if (obj)
252 		got_object_close(obj);
253 	free(id);
254 	return err;
255 }
256 
257 static const struct got_error *
258 list_refs(struct imsg *imsg)
259 {
260 	const struct got_error *err;
261 	struct repo_read_client *client = &repo_read_client;
262 	struct got_reflist_head refs;
263 	struct got_reflist_entry *re;
264 	struct gotd_imsg_list_refs_internal ireq;
265 	size_t datalen;
266 	struct gotd_imsg_reflist irefs;
267 	struct imsgbuf ibuf;
268 	int client_fd = imsg->fd;
269 	struct got_object_id *head_target_id = NULL;
270 
271 	TAILQ_INIT(&refs);
272 
273 	if (client_fd == -1)
274 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
275 
276 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
277 	if (datalen != sizeof(ireq))
278 		return got_error(GOT_ERR_PRIVSEP_LEN);
279 	memcpy(&ireq, imsg->data, sizeof(ireq));
280 
281 	if (ireq.client_id == 0)
282 		return got_error(GOT_ERR_CLIENT_ID);
283 	if (client->id != 0) {
284 		return got_error_msg(GOT_ERR_CLIENT_ID,
285 		    "duplicate list-refs request");
286 	}
287 	client->id = ireq.client_id;
288 	client->fd = client_fd;
289 
290 	imsg_init(&ibuf, client_fd);
291 
292 	err = got_ref_list(&refs, repo_read.repo, "",
293 	    got_ref_cmp_by_name, NULL);
294 	if (err)
295 		return err;
296 
297 	memset(&irefs, 0, sizeof(irefs));
298 	TAILQ_FOREACH(re, &refs, entry) {
299 		struct got_object_id *id;
300 		int obj_type;
301 
302 		if (got_ref_is_symbolic(re->ref)) {
303 			const char *refname = got_ref_get_name(re->ref);
304 			if (strcmp(refname, GOT_REF_HEAD) != 0)
305 				continue;
306 			err = got_ref_resolve(&head_target_id, repo_read.repo,
307 			    re->ref);
308 			if (err) {
309 				if (err->code != GOT_ERR_NOT_REF)
310 					return err;
311 				/*
312 				 * HEAD points to a non-existent branch.
313 				 * Do not advertise it.
314 				 * Matches git-daemon's behaviour.
315 				 */
316 				head_target_id = NULL;
317 				err = NULL;
318 			} else
319 				irefs.nrefs++;
320 			continue;
321 		}
322 
323 		irefs.nrefs++;
324 
325 		/* Account for a peeled tag refs. */
326 		err = got_ref_resolve(&id, repo_read.repo, re->ref);
327 		if (err)
328 			goto done;
329 		err = got_object_get_type(&obj_type, repo_read.repo, id);
330 		free(id);
331 		if (err)
332 			goto done;
333 		if (obj_type == GOT_OBJ_TYPE_TAG)
334 			irefs.nrefs++;
335 	}
336 
337 	if (imsg_compose(&ibuf, GOTD_IMSG_REFLIST, PROC_REPO_READ,
338 	    repo_read.pid, -1, &irefs, sizeof(irefs)) == -1) {
339 		err = got_error_from_errno("imsg_compose REFLIST");
340 		goto done;
341 	}
342 
343 	/*
344 	 * Send the HEAD symref first. In Git-protocol versions < 2
345 	 * the HEAD symref must be announced on the initial line of
346 	 * the server's ref advertisement.
347 	 * For now, we do not advertise symrefs other than HEAD.
348 	 */
349 	TAILQ_FOREACH(re, &refs, entry) {
350 		if (!got_ref_is_symbolic(re->ref) ||
351 		    strcmp(got_ref_get_name(re->ref), GOT_REF_HEAD) != 0 ||
352 		    head_target_id == NULL)
353 			continue;
354 		err = send_symref(re->ref, head_target_id, &ibuf);
355 		if (err)
356 			goto done;
357 		break;
358 	}
359 	TAILQ_FOREACH(re, &refs, entry) {
360 		if (got_ref_is_symbolic(re->ref))
361 			continue;
362 		err = send_ref(re->ref, &ibuf);
363 		if (err)
364 			goto done;
365 	}
366 
367 	err = gotd_imsg_flush(&ibuf);
368 done:
369 	got_ref_list_free(&refs);
370 	imsg_clear(&ibuf);
371 	return err;
372 }
373 
374 static const struct got_error *
375 append_object_id(struct got_object_id *id, void *data, void *arg)
376 {
377 	struct gotd_object_id_array *array = arg;
378 	const size_t alloc_chunksz = 256;
379 
380 	if (array->ids == NULL) {
381 		array->ids = reallocarray(NULL, alloc_chunksz,
382 		    sizeof(*array->ids));
383 		if (array->ids == NULL)
384 			return got_error_from_errno("reallocarray");
385 		array->nalloc = alloc_chunksz;
386 		array->nids = 0;
387 	} else if (array->nalloc <= array->nids) {
388 		struct got_object_id **new;
389 		new = recallocarray(array->ids, array->nalloc,
390 		    array->nalloc + alloc_chunksz, sizeof(*new));
391 		if (new == NULL)
392 			return got_error_from_errno("recallocarray");
393 		array->ids = new;
394 		array->nalloc += alloc_chunksz;
395 	}
396 
397 	array->ids[array->nids] = id;
398 	array->nids++;
399 	return NULL;
400 }
401 
402 static const struct got_error *
403 recv_want(struct imsg *imsg)
404 {
405 	const struct got_error *err;
406 	struct repo_read_client *client = &repo_read_client;
407 	struct gotd_imsg_want iwant;
408 	size_t datalen;
409 	char hex[SHA1_DIGEST_STRING_LENGTH];
410 	struct got_object_id id;
411 	int obj_type;
412 	struct imsgbuf ibuf;
413 
414 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
415 	if (datalen != sizeof(iwant))
416 		return got_error(GOT_ERR_PRIVSEP_LEN);
417 	memcpy(&iwant, imsg->data, sizeof(iwant));
418 
419 	memset(&id, 0, sizeof(id));
420 	memcpy(id.sha1, iwant.object_id, SHA1_DIGEST_LENGTH);
421 
422 	if (log_getverbose() > 0 &&
423 	    got_sha1_digest_to_str(id.sha1, hex, sizeof(hex)))
424 		log_debug("client wants %s", hex);
425 
426 	imsg_init(&ibuf, client->fd);
427 
428 	err = got_object_get_type(&obj_type, repo_read.repo, &id);
429 	if (err)
430 		return err;
431 
432 	if (obj_type != GOT_OBJ_TYPE_COMMIT &&
433 	    obj_type != GOT_OBJ_TYPE_TAG)
434 		return got_error(GOT_ERR_OBJ_TYPE);
435 
436 	if (!got_object_idset_contains(client->want_ids, &id)) {
437 		err = got_object_idset_add(client->want_ids, &id, NULL);
438 		if (err)
439 			return err;
440 	}
441 
442 	gotd_imsg_send_ack(&id, &ibuf, PROC_REPO_READ, repo_read.pid);
443 	imsg_clear(&ibuf);
444 	return err;
445 }
446 
447 static const struct got_error *
448 recv_have(struct imsg *imsg)
449 {
450 	const struct got_error *err;
451 	struct repo_read_client *client = &repo_read_client;
452 	struct gotd_imsg_have ihave;
453 	size_t datalen;
454 	char hex[SHA1_DIGEST_STRING_LENGTH];
455 	struct got_object_id id;
456 	int obj_type;
457 	struct imsgbuf ibuf;
458 
459 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
460 	if (datalen != sizeof(ihave))
461 		return got_error(GOT_ERR_PRIVSEP_LEN);
462 	memcpy(&ihave, imsg->data, sizeof(ihave));
463 
464 	memset(&id, 0, sizeof(id));
465 	memcpy(id.sha1, ihave.object_id, SHA1_DIGEST_LENGTH);
466 
467 	if (log_getverbose() > 0 &&
468 	    got_sha1_digest_to_str(id.sha1, hex, sizeof(hex)))
469 		log_debug("client has %s", hex);
470 
471 	imsg_init(&ibuf, client->fd);
472 
473 	err = got_object_get_type(&obj_type, repo_read.repo, &id);
474 	if (err) {
475 		if (err->code == GOT_ERR_NO_OBJ) {
476 			gotd_imsg_send_nak(&id, &ibuf,
477 			    PROC_REPO_READ, repo_read.pid);
478 			err = NULL;
479 		}
480 		goto done;
481 	}
482 
483 	if (obj_type != GOT_OBJ_TYPE_COMMIT &&
484 	    obj_type != GOT_OBJ_TYPE_TAG) {
485 		gotd_imsg_send_nak(&id, &ibuf, PROC_REPO_READ, repo_read.pid);
486 		err = got_error(GOT_ERR_OBJ_TYPE);
487 		goto done;
488 	}
489 
490 	if (!got_object_idset_contains(client->have_ids, &id)) {
491 		err = got_object_idset_add(client->have_ids, &id, NULL);
492 		if (err)
493 			goto done;
494 	}
495 
496 	gotd_imsg_send_ack(&id, &ibuf, PROC_REPO_READ, repo_read.pid);
497 done:
498 	imsg_clear(&ibuf);
499 	return err;
500 }
501 
502 struct repo_read_pack_progress_arg {
503 	int report_progress;
504 	struct imsgbuf *ibuf;
505 	int sent_ready;
506 };
507 
508 static const struct got_error *
509 pack_progress(void *arg, int ncolored, int nfound, int ntrees,
510     off_t packfile_size, int ncommits, int nobj_total, int nobj_deltify,
511     int nobj_written)
512 {
513 	struct repo_read_pack_progress_arg *a = arg;
514 	struct gotd_imsg_packfile_progress iprog;
515 	int ret;
516 
517 	if (!a->report_progress)
518 		return NULL;
519 	if (packfile_size > 0 && a->sent_ready)
520 		return NULL;
521 
522 	memset(&iprog, 0, sizeof(iprog));
523 	iprog.ncolored = ncolored;
524 	iprog.nfound = nfound;
525 	iprog.ntrees = ntrees;
526 	iprog.packfile_size = packfile_size;
527 	iprog.ncommits = ncommits;
528 	iprog.nobj_total = nobj_total;
529 	iprog.nobj_deltify = nobj_deltify;
530 	iprog.nobj_written = nobj_written;
531 
532 	/* Using synchronous writes since we are blocking the event loop. */
533 	if (packfile_size == 0) {
534 		ret = imsg_compose(a->ibuf, GOTD_IMSG_PACKFILE_PROGRESS,
535 		    PROC_REPO_READ, repo_read.pid, -1, &iprog, sizeof(iprog));
536 		if (ret == -1) {
537 			return got_error_from_errno("imsg compose "
538 			    "PACKFILE_PROGRESS");
539 		}
540 	} else {
541 		a->sent_ready = 1;
542 		ret = imsg_compose(a->ibuf, GOTD_IMSG_PACKFILE_READY,
543 		    PROC_REPO_READ, repo_read.pid, -1, &iprog, sizeof(iprog));
544 		if (ret == -1) {
545 			return got_error_from_errno("imsg compose "
546 			    "PACKFILE_READY");
547 		}
548 	}
549 
550 	return gotd_imsg_flush(a->ibuf);
551 }
552 
553 static const struct got_error *
554 receive_delta_cache_fd(struct imsg *imsg,
555     struct gotd_imsgev *iev)
556 {
557 	struct repo_read_client *client = &repo_read_client;
558 	struct gotd_imsg_send_packfile ireq;
559 	size_t datalen;
560 
561 	log_debug("receving delta cache file");
562 
563 	if (imsg->fd == -1)
564 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
565 
566 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
567 	if (datalen != sizeof(ireq))
568 		return got_error(GOT_ERR_PRIVSEP_LEN);
569 	memcpy(&ireq, imsg->data, sizeof(ireq));
570 
571 	if (client->delta_cache_fd != -1)
572 		return got_error(GOT_ERR_PRIVSEP_MSG);
573 
574 	client->delta_cache_fd = imsg->fd;
575 	client->report_progress = ireq.report_progress;
576 	return NULL;
577 }
578 
579 static const struct got_error *
580 receive_pack_pipe(struct imsg *imsg, struct gotd_imsgev *iev)
581 {
582 	struct repo_read_client *client = &repo_read_client;
583 	struct gotd_imsg_packfile_pipe ireq;
584 	size_t datalen;
585 
586 	log_debug("receving pack pipe descriptor");
587 
588 	if (imsg->fd == -1)
589 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
590 
591 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
592 	if (datalen != sizeof(ireq))
593 		return got_error(GOT_ERR_PRIVSEP_LEN);
594 	memcpy(&ireq, imsg->data, sizeof(ireq));
595 
596 	if (client->pack_pipe != -1)
597 		return got_error(GOT_ERR_PRIVSEP_MSG);
598 
599 	client->pack_pipe = imsg->fd;
600 	return NULL;
601 }
602 
603 static const struct got_error *
604 send_packfile(struct imsg *imsg, struct gotd_imsgev *iev)
605 {
606 	const struct got_error *err = NULL;
607 	struct repo_read_client *client = &repo_read_client;
608 	struct gotd_imsg_packfile_done idone;
609 	uint8_t packsha1[SHA1_DIGEST_LENGTH];
610 	char hex[SHA1_DIGEST_STRING_LENGTH];
611 	FILE *delta_cache = NULL;
612 	struct imsgbuf ibuf;
613 	struct repo_read_pack_progress_arg pa;
614 	struct got_ratelimit rl;
615 	struct gotd_object_id_array want_ids;
616 	struct gotd_object_id_array have_ids;
617 
618 	log_debug("packfile request received");
619 
620 	memset(&want_ids, 0, sizeof(want_ids));
621 	memset(&have_ids, 0, sizeof(have_ids));
622 
623 	got_ratelimit_init(&rl, 2, 0);
624 
625 	if (client->delta_cache_fd == -1 || client->pack_pipe == -1)
626 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
627 
628 	imsg_init(&ibuf, client->fd);
629 
630 	delta_cache = fdopen(client->delta_cache_fd, "w+");
631 	if (delta_cache == NULL) {
632 		err = got_error_from_errno("fdopen");
633 		goto done;
634 	}
635 	client->delta_cache_fd = -1;
636 
637 	memset(&pa, 0, sizeof(pa));
638 	pa.ibuf = &ibuf;
639 	pa.report_progress = client->report_progress;
640 
641 	err = got_object_idset_for_each(client->want_ids,
642 	    append_object_id, &want_ids);
643 	if (err)
644 		goto done;
645 	err = got_object_idset_for_each(client->have_ids,
646 	   append_object_id, &have_ids);
647 	if (err)
648 		goto done;
649 
650 	err = got_pack_create(packsha1, client->pack_pipe, delta_cache,
651 	    have_ids.ids, have_ids.nids, want_ids.ids, want_ids.nids,
652 	    repo_read.repo, 0, 1, 0, pack_progress, &pa, &rl,
653 	    check_cancelled, NULL);
654 	if (err)
655 		goto done;
656 
657 	if (log_getverbose() > 0 &&
658 	    got_sha1_digest_to_str(packsha1, hex, sizeof(hex)))
659 		log_debug("sent pack-%s.pack", hex);
660 
661 	memset(&idone, 0, sizeof(idone));
662 	idone.client_id = client->id;
663 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_PACKFILE_DONE,
664 	    PROC_REPO_READ, -1, &idone, sizeof(idone)) == -1)
665 		err = got_error_from_errno("imsg compose PACKFILE_DONE");
666 done:
667 	if (delta_cache != NULL && fclose(delta_cache) == EOF && err == NULL)
668 		err = got_error_from_errno("fclose");
669 	imsg_clear(&ibuf);
670 	free(want_ids.ids);
671 	free(have_ids.ids);
672 	return err;
673 }
674 
675 static void
676 repo_read_dispatch_session(int fd, short event, void *arg)
677 {
678 	const struct got_error *err = NULL;
679 	struct gotd_imsgev *iev = arg;
680 	struct imsgbuf *ibuf = &iev->ibuf;
681 	struct imsg imsg;
682 	ssize_t n;
683 	int shut = 0;
684 	struct repo_read_client *client = &repo_read_client;
685 
686 	if (event & EV_READ) {
687 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
688 			fatal("imsg_read error");
689 		if (n == 0)	/* Connection closed. */
690 			shut = 1;
691 	}
692 
693 	if (event & EV_WRITE) {
694 		n = msgbuf_write(&ibuf->w);
695 		if (n == -1 && errno != EAGAIN)
696 			fatal("msgbuf_write");
697 		if (n == 0)	/* Connection closed. */
698 			shut = 1;
699 	}
700 
701 	while (err == NULL && check_cancelled(NULL) == NULL) {
702 		if ((n = imsg_get(ibuf, &imsg)) == -1)
703 			fatal("%s: imsg_get", __func__);
704 		if (n == 0)	/* No more messages. */
705 			break;
706 
707 		if (imsg.hdr.type != GOTD_IMSG_LIST_REFS_INTERNAL &&
708 		    client->id == 0) {
709 			err = got_error(GOT_ERR_PRIVSEP_MSG);
710 			break;
711 		}
712 
713 		switch (imsg.hdr.type) {
714 		case GOTD_IMSG_LIST_REFS_INTERNAL:
715 			err = list_refs(&imsg);
716 			if (err)
717 				log_warnx("ls-refs: %s", err->msg);
718 			break;
719 		case GOTD_IMSG_WANT:
720 			err = recv_want(&imsg);
721 			if (err)
722 				log_warnx("want-line: %s", err->msg);
723 			break;
724 		case GOTD_IMSG_HAVE:
725 			err = recv_have(&imsg);
726 			if (err)
727 				log_warnx("have-line: %s", err->msg);
728 			break;
729 		case GOTD_IMSG_SEND_PACKFILE:
730 			err = receive_delta_cache_fd(&imsg, iev);
731 			if (err)
732 				log_warnx("receiving delta cache: %s",
733 				    err->msg);
734 			break;
735 		case GOTD_IMSG_PACKFILE_PIPE:
736 			err = receive_pack_pipe(&imsg, iev);
737 			if (err) {
738 				log_warnx("receiving pack pipe: %s", err->msg);
739 				break;
740 			}
741 			err = send_packfile(&imsg, iev);
742 			if (err)
743 				log_warnx("sending packfile: %s", err->msg);
744 			break;
745 		default:
746 			log_debug("unexpected imsg %d", imsg.hdr.type);
747 			break;
748 		}
749 
750 		imsg_free(&imsg);
751 	}
752 
753 	if (!shut && check_cancelled(NULL) == NULL) {
754 		if (err &&
755 		    gotd_imsg_send_error_event(iev, PROC_REPO_READ,
756 		        client->id, err) == -1) {
757 			log_warnx("could not send error to parent: %s",
758 			    err->msg);
759 		}
760 		gotd_imsg_event_add(iev);
761 	} else {
762 		/* This pipe is dead. Remove its event handler */
763 		event_del(&iev->ev);
764 		event_loopexit(NULL);
765 	}
766 }
767 
768 static const struct got_error *
769 recv_connect(struct imsg *imsg)
770 {
771 	struct gotd_imsgev *iev = &repo_read.session_iev;
772 	size_t datalen;
773 
774 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
775 	if (datalen != 0)
776 		return got_error(GOT_ERR_PRIVSEP_LEN);
777 	if (imsg->fd == -1)
778 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
779 
780 	if (repo_read.session_fd != -1)
781 		return got_error(GOT_ERR_PRIVSEP_MSG);
782 
783 	repo_read.session_fd = imsg->fd;
784 
785 	imsg_init(&iev->ibuf, repo_read.session_fd);
786 	iev->handler = repo_read_dispatch_session;
787 	iev->events = EV_READ;
788 	iev->handler_arg = NULL;
789 	event_set(&iev->ev, iev->ibuf.fd, EV_READ,
790 	    repo_read_dispatch_session, iev);
791 	gotd_imsg_event_add(iev);
792 
793 	return NULL;
794 }
795 
796 static void
797 repo_read_dispatch(int fd, short event, void *arg)
798 {
799 	const struct got_error *err = NULL;
800 	struct gotd_imsgev *iev = arg;
801 	struct imsgbuf *ibuf = &iev->ibuf;
802 	struct imsg imsg;
803 	ssize_t n;
804 	int shut = 0;
805 	struct repo_read_client *client = &repo_read_client;
806 
807 	if (event & EV_READ) {
808 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
809 			fatal("imsg_read error");
810 		if (n == 0)	/* Connection closed. */
811 			shut = 1;
812 	}
813 
814 	if (event & EV_WRITE) {
815 		n = msgbuf_write(&ibuf->w);
816 		if (n == -1 && errno != EAGAIN)
817 			fatal("msgbuf_write");
818 		if (n == 0)	/* Connection closed. */
819 			shut = 1;
820 	}
821 
822 	while (err == NULL && check_cancelled(NULL) == NULL) {
823 		if ((n = imsg_get(ibuf, &imsg)) == -1)
824 			fatal("%s: imsg_get", __func__);
825 		if (n == 0)	/* No more messages. */
826 			break;
827 
828 		switch (imsg.hdr.type) {
829 		case GOTD_IMSG_CONNECT_REPO_CHILD:
830 			err = recv_connect(&imsg);
831 			break;
832 		default:
833 			log_debug("unexpected imsg %d", imsg.hdr.type);
834 			break;
835 		}
836 
837 		imsg_free(&imsg);
838 	}
839 
840 	if (!shut && check_cancelled(NULL) == NULL) {
841 		if (err &&
842 		    gotd_imsg_send_error_event(iev, PROC_REPO_READ,
843 		        client->id, err) == -1) {
844 			log_warnx("could not send error to parent: %s",
845 			    err->msg);
846 		}
847 		gotd_imsg_event_add(iev);
848 	} else {
849 		/* This pipe is dead. Remove its event handler */
850 		event_del(&iev->ev);
851 		event_loopexit(NULL);
852 	}
853 }
854 
855 void
856 repo_read_main(const char *title, const char *repo_path,
857     int *pack_fds, int *temp_fds)
858 {
859 	const struct got_error *err = NULL;
860 	struct repo_read_client *client = &repo_read_client;
861 	struct gotd_imsgev iev;
862 
863 	client->fd = -1;
864 	client->delta_cache_fd = -1;
865 	client->pack_pipe = -1;
866 	client->have_ids = got_object_idset_alloc();
867 	if (client->have_ids == NULL) {
868 		err = got_error_from_errno("got_object_idset_alloc");
869 		goto done;
870 	}
871 	client->want_ids = got_object_idset_alloc();
872 	if (client->want_ids == NULL) {
873 		err = got_error_from_errno("got_object_idset_alloc");
874 		goto done;
875 	}
876 
877 	repo_read.title = title;
878 	repo_read.pid = getpid();
879 	repo_read.pack_fds = pack_fds;
880 	repo_read.temp_fds = temp_fds;
881 	repo_read.session_fd = -1;
882 	repo_read.session_iev.ibuf.fd = -1;
883 
884 	err = got_repo_open(&repo_read.repo, repo_path, NULL, pack_fds);
885 	if (err)
886 		goto done;
887 	if (!got_repo_is_bare(repo_read.repo)) {
888 		err = got_error_msg(GOT_ERR_NOT_GIT_REPO,
889 		    "bare git repository required");
890 		goto done;
891 	}
892 
893 	got_repo_temp_fds_set(repo_read.repo, temp_fds);
894 
895 	signal(SIGINT, catch_sigint);
896 	signal(SIGTERM, catch_sigterm);
897 	signal(SIGPIPE, SIG_IGN);
898 	signal(SIGHUP, SIG_IGN);
899 
900 	imsg_init(&iev.ibuf, GOTD_FILENO_MSG_PIPE);
901 	iev.handler = repo_read_dispatch;
902 	iev.events = EV_READ;
903 	iev.handler_arg = NULL;
904 	event_set(&iev.ev, iev.ibuf.fd, EV_READ, repo_read_dispatch, &iev);
905 
906 	if (gotd_imsg_compose_event(&iev, GOTD_IMSG_REPO_CHILD_READY,
907 	    PROC_REPO_READ, -1, NULL, 0) == -1) {
908 		err = got_error_from_errno("imsg compose REPO_CHILD_READY");
909 		goto done;
910 	}
911 
912 	event_dispatch();
913 done:
914 	if (err)
915 		log_warnx("%s: %s", title, err->msg);
916 	repo_read_shutdown();
917 }
918 
919 void
920 repo_read_shutdown(void)
921 {
922 	struct repo_read_client *client = &repo_read_client;
923 
924 	log_debug("shutting down");
925 
926 	if (client->have_ids)
927 		got_object_idset_free(client->have_ids);
928 	if (client->want_ids)
929 		got_object_idset_free(client->want_ids);
930 	if (client->fd != -1)
931 		close(client->fd);
932 	if (client->delta_cache_fd != -1)
933 		close(client->delta_cache_fd);
934 	if (client->pack_pipe != -1)
935 		close(client->pack_pipe);
936 
937 	if (repo_read.repo)
938 		got_repo_close(repo_read.repo);
939 	got_repo_pack_fds_close(repo_read.pack_fds);
940 	got_repo_temp_fds_close(repo_read.temp_fds);
941 	if (repo_read.session_fd != -1)
942 		close(repo_read.session_fd);
943 	exit(0);
944 }