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 <sha1.h>
28 #include <siphash.h>
29 #include <stdio.h>
30 #include <string.h>
31 #include <unistd.h>
32 
33 #include "got_error.h"
34 #include "got_cancel.h"
35 #include "got_object.h"
36 #include "got_repository.h"
37 #include "got_reference.h"
38 #include "got_repository_admin.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_sha1.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 } repo_read;
64 
65 struct repo_read_client {
66 	STAILQ_ENTRY(repo_read_client)	 entry;
67 	uint32_t			 id;
68 	int				 fd;
69 	int				 delta_cache_fd;
70 	int				 report_progress;
71 	int				 pack_pipe;
72 	struct gotd_object_id_array	 want_ids;
73 	struct gotd_object_id_array	 have_ids;
74 };
75 STAILQ_HEAD(repo_read_clients, repo_read_client);
76 
77 static struct repo_read_clients repo_read_clients[GOTD_CLIENT_TABLE_SIZE];
78 static SIPHASH_KEY clients_hash_key;
79 
80 static uint64_t
81 client_hash(uint32_t client_id)
82 {
83 	return SipHash24(&clients_hash_key, &client_id, sizeof(client_id));
84 }
85 
86 static void
87 add_client(struct repo_read_client *client, uint32_t client_id, int fd)
88 {
89 	uint64_t slot;
90 
91 	client->id = client_id;
92 	client->fd = fd;
93 	client->delta_cache_fd = -1;
94 	client->pack_pipe = -1;
95 	slot = client_hash(client->id) % nitems(repo_read_clients);
96 	STAILQ_INSERT_HEAD(&repo_read_clients[slot], client, entry);
97 }
98 
99 static struct repo_read_client *
100 find_client(uint32_t client_id)
101 {
102 	uint64_t slot;
103 	struct repo_read_client *c;
104 
105 	slot = client_hash(client_id) % nitems(repo_read_clients);
106 	STAILQ_FOREACH(c, &repo_read_clients[slot], entry) {
107 		if (c->id == client_id)
108 			return c;
109 	}
110 
111 	return NULL;
112 }
113 
114 static volatile sig_atomic_t sigint_received;
115 static volatile sig_atomic_t sigterm_received;
116 
117 static void
118 catch_sigint(int signo)
119 {
120 	sigint_received = 1;
121 }
122 
123 static void
124 catch_sigterm(int signo)
125 {
126 	sigterm_received = 1;
127 }
128 
129 static const struct got_error *
130 check_cancelled(void *arg)
131 {
132 	if (sigint_received || sigterm_received)
133 		return got_error(GOT_ERR_CANCELLED);
134 
135 	return NULL;
136 }
137 
138 static const struct got_error *
139 send_symref(struct got_reference *symref, struct got_object_id *target_id,
140     struct imsgbuf *ibuf)
141 {
142 	const struct got_error *err = NULL;
143 	struct gotd_imsg_symref isymref;
144 	const char *refname = got_ref_get_name(symref);
145 	const char *target = got_ref_get_symref_target(symref);
146 	size_t len;
147 	struct ibuf *wbuf;
148 
149 	memset(&isymref, 0, sizeof(isymref));
150 	isymref.name_len = strlen(refname);
151 	isymref.target_len = strlen(target);
152 	memcpy(isymref.target_id, target_id->sha1, sizeof(isymref.target_id));
153 
154 	len = sizeof(isymref) + isymref.name_len + isymref.target_len;
155 	if (len > MAX_IMSGSIZE - IMSG_HEADER_SIZE) {
156 		err = got_error(GOT_ERR_NO_SPACE);
157 		goto done;
158 	}
159 
160 	wbuf = imsg_create(ibuf, GOTD_IMSG_SYMREF, 0, 0, len);
161 	if (wbuf == NULL) {
162 		err = got_error_from_errno("imsg_create SYMREF");
163 		goto done;
164 	}
165 
166 	if (imsg_add(wbuf, &isymref, sizeof(isymref)) == -1) {
167 		err = got_error_from_errno("imsg_add SYMREF");
168 		goto done;
169 	}
170 	if (imsg_add(wbuf, refname, isymref.name_len) == -1) {
171 		err = got_error_from_errno("imsg_add SYMREF");
172 		goto done;
173 	}
174 	if (imsg_add(wbuf, target, isymref.target_len) == -1) {
175 		err = got_error_from_errno("imsg_add SYMREF");
176 		goto done;
177 	}
178 
179 	wbuf->fd = -1;
180 	imsg_close(ibuf, wbuf);
181 done:
182 	free(target_id);
183 	return err;
184 }
185 
186 static const struct got_error *
187 send_peeled_tag_ref(struct got_reference *ref, struct got_object *obj,
188     struct imsgbuf *ibuf)
189 {
190 	const struct got_error *err = NULL;
191 	struct got_tag_object *tag;
192 	size_t namelen, len;
193 	char *peeled_refname = NULL;
194 	struct got_object_id *id;
195 	struct ibuf *wbuf;
196 
197 	err = got_object_tag_open(&tag, repo_read.repo, obj);
198 	if (err)
199 		return err;
200 
201 	if (asprintf(&peeled_refname, "%s^{}", got_ref_get_name(ref)) == -1) {
202 		err = got_error_from_errno("asprintf");
203 		goto done;
204 	}
205 
206 	id = got_object_tag_get_object_id(tag);
207 	namelen = strlen(peeled_refname);
208 
209 	len = sizeof(struct gotd_imsg_ref) + namelen;
210 	if (len > MAX_IMSGSIZE - IMSG_HEADER_SIZE) {
211 		err = got_error(GOT_ERR_NO_SPACE);
212 		goto done;
213 	}
214 
215 	wbuf = imsg_create(ibuf, GOTD_IMSG_REF, PROC_REPO_READ,
216 	    repo_read.pid, len);
217 	if (wbuf == NULL) {
218 		err = got_error_from_errno("imsg_create MREF");
219 		goto done;
220 	}
221 
222 	/* Keep in sync with struct gotd_imsg_ref definition. */
223 	if (imsg_add(wbuf, id->sha1, SHA1_DIGEST_LENGTH) == -1) {
224 		err = got_error_from_errno("imsg_add REF");
225 		goto done;
226 	}
227 	if (imsg_add(wbuf, &namelen, sizeof(namelen)) == -1) {
228 		err = got_error_from_errno("imsg_add REF");
229 		goto done;
230 	}
231 	if (imsg_add(wbuf, peeled_refname, namelen) == -1) {
232 		err = got_error_from_errno("imsg_add REF");
233 		goto done;
234 	}
235 
236 	wbuf->fd = -1;
237 	imsg_close(ibuf, wbuf);
238 done:
239 	got_object_tag_close(tag);
240 	return err;
241 }
242 
243 static const struct got_error *
244 send_ref(struct got_reference *ref, struct imsgbuf *ibuf)
245 {
246 	const struct got_error *err;
247 	const char *refname = got_ref_get_name(ref);
248 	size_t namelen;
249 	struct got_object_id *id = NULL;
250 	struct got_object *obj = NULL;
251 	size_t len;
252 	struct ibuf *wbuf;
253 
254 	namelen = strlen(refname);
255 
256 	len = sizeof(struct gotd_imsg_ref) + namelen;
257 	if (len > MAX_IMSGSIZE - IMSG_HEADER_SIZE)
258 		return got_error(GOT_ERR_NO_SPACE);
259 
260 	err = got_ref_resolve(&id, repo_read.repo, ref);
261 	if (err)
262 		return err;
263 
264 	wbuf = imsg_create(ibuf, GOTD_IMSG_REF, PROC_REPO_READ,
265 	    repo_read.pid, len);
266 	if (wbuf == NULL) {
267 		err = got_error_from_errno("imsg_create REF");
268 		goto done;
269 	}
270 
271 	/* Keep in sync with struct gotd_imsg_ref definition. */
272 	if (imsg_add(wbuf, id->sha1, SHA1_DIGEST_LENGTH) == -1)
273 		return got_error_from_errno("imsg_add REF");
274 	if (imsg_add(wbuf, &namelen, sizeof(namelen)) == -1)
275 		return got_error_from_errno("imsg_add REF");
276 	if (imsg_add(wbuf, refname, namelen) == -1)
277 		return got_error_from_errno("imsg_add REF");
278 
279 	wbuf->fd = -1;
280 	imsg_close(ibuf, wbuf);
281 
282 	err = got_object_open(&obj, repo_read.repo, id);
283 	if (err)
284 		goto done;
285 	if (obj->type == GOT_OBJ_TYPE_TAG)
286 		err = send_peeled_tag_ref(ref, obj, ibuf);
287 done:
288 	if (obj)
289 		got_object_close(obj);
290 	free(id);
291 	return err;
292 }
293 
294 static const struct got_error *
295 list_refs(struct repo_read_client **client, struct imsg *imsg)
296 {
297 	const struct got_error *err;
298 	struct got_reflist_head refs;
299 	struct got_reflist_entry *re;
300 	struct gotd_imsg_list_refs_internal ireq;
301 	size_t datalen;
302 	struct gotd_imsg_reflist irefs;
303 	struct imsgbuf ibuf;
304 	int client_fd = imsg->fd;
305 	struct got_object_id *head_target_id = NULL;
306 
307 	TAILQ_INIT(&refs);
308 
309 	if (client_fd == -1)
310 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
311 
312 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
313 	if (datalen != sizeof(ireq))
314 		return got_error(GOT_ERR_PRIVSEP_LEN);
315 	memcpy(&ireq, imsg->data, sizeof(ireq));
316 
317 	*client = find_client(ireq.client_id);
318 	if (*client)
319 		return got_error_msg(GOT_ERR_CLIENT_ID, "duplicate client ID");
320 
321 	*client = calloc(1, sizeof(**client));
322 	if (*client == NULL)
323 		return got_error_from_errno("calloc");
324 	add_client(*client, ireq.client_id, client_fd);
325 
326 	imsg_init(&ibuf, client_fd);
327 
328 	err = got_ref_list(&refs, repo_read.repo, "",
329 	    got_ref_cmp_by_name, NULL);
330 	if (err)
331 		return err;
332 
333 	memset(&irefs, 0, sizeof(irefs));
334 	TAILQ_FOREACH(re, &refs, entry) {
335 		struct got_object_id *id;
336 		int obj_type;
337 
338 		if (got_ref_is_symbolic(re->ref)) {
339 			const char *refname = got_ref_get_name(re->ref);
340 			if (strcmp(refname, GOT_REF_HEAD) != 0)
341 				continue;
342 			err = got_ref_resolve(&head_target_id, repo_read.repo,
343 			    re->ref);
344 			if (err) {
345 				if (err->code != GOT_ERR_NOT_REF)
346 					return err;
347 				/*
348 				 * HEAD points to a non-existent branch.
349 				 * Do not advertise it.
350 				 * Matches git-daemon's behaviour.
351 				 */
352 				head_target_id = NULL;
353 				err = NULL;
354 			} else
355 				irefs.nrefs++;
356 			continue;
357 		}
358 
359 		irefs.nrefs++;
360 
361 		/* Account for a peeled tag refs. */
362 		err = got_ref_resolve(&id, repo_read.repo, re->ref);
363 		if (err)
364 			goto done;
365 		err = got_object_get_type(&obj_type, repo_read.repo, id);	
366 		free(id);
367 		if (err)
368 			goto done;
369 		if (obj_type == GOT_OBJ_TYPE_TAG)
370 			irefs.nrefs++;
371 	}
372 
373 	if (imsg_compose(&ibuf, GOTD_IMSG_REFLIST, PROC_REPO_READ,
374 	    repo_read.pid, -1, &irefs, sizeof(irefs)) == -1) {
375 		err = got_error_from_errno("imsg_compose REFLIST");
376 		goto done;
377 	}
378 
379 	/*
380 	 * Send the HEAD symref first. In Git-protocol versions < 2
381 	 * the HEAD symref must be announced on the initial line of
382 	 * the server's ref advertisement.
383 	 * For now, we do not advertise symrefs other than HEAD.
384 	 */
385 	TAILQ_FOREACH(re, &refs, entry) {
386 		if (!got_ref_is_symbolic(re->ref) ||
387 		    strcmp(got_ref_get_name(re->ref), GOT_REF_HEAD) != 0 ||
388 		    head_target_id == NULL)
389 			continue;
390 		err = send_symref(re->ref, head_target_id, &ibuf);
391 		if (err)
392 			goto done;
393 		break;
394 	}
395 	TAILQ_FOREACH(re, &refs, entry) {
396 		if (got_ref_is_symbolic(re->ref))
397 			continue;
398 		err = send_ref(re->ref, &ibuf);
399 		if (err)
400 			goto done;
401 	}
402 
403 	err = gotd_imsg_flush(&ibuf);
404 done:
405 	got_ref_list_free(&refs);
406 	imsg_clear(&ibuf);
407 	return err;
408 }
409 
410 static const struct got_error *
411 record_object_id(struct gotd_object_id_array *array, struct got_object_id *id)
412 {
413 	const size_t alloc_chunksz = 256;
414 
415 	if (array->ids == NULL) {
416 		array->ids = reallocarray(NULL, alloc_chunksz,
417 		    sizeof(*array->ids));
418 		if (array->ids == NULL)
419 			return got_error_from_errno("reallocarray");
420 		array->nalloc = alloc_chunksz;
421 		array->nids = 0;
422 	} else if (array->nalloc <= array->nids) {
423 		struct got_object_id **new;
424 		new = recallocarray(array->ids, array->nalloc,
425 		    array->nalloc + alloc_chunksz, sizeof(*new));
426 		if (new == NULL)
427 			return got_error_from_errno("recallocarray");
428 		array->ids = new;
429 		array->nalloc += alloc_chunksz;
430 	}
431 
432 	array->ids[array->nids] = got_object_id_dup(id);
433 	if (array->ids[array->nids] == NULL)
434 		return got_error_from_errno("got_object_id_dup");
435 	array->nids++;
436 	return NULL;
437 }
438 
439 static void
440 free_object_ids(struct gotd_object_id_array *array)
441 {
442 	size_t i;
443 
444 	for (i = 0; i < array->nids; i++)
445 		free(array->ids[i]);
446 	free(array->ids);
447 
448 	array->ids = NULL;
449 	array->nalloc = 0;
450 	array->nids = 0;
451 }
452 
453 static const struct got_error *
454 recv_want(struct repo_read_client **client, struct imsg *imsg)
455 {
456 	const struct got_error *err;
457 	struct gotd_imsg_want iwant;
458 	size_t datalen;
459 	char hex[SHA1_DIGEST_STRING_LENGTH];
460 	struct got_object_id id;
461 	int obj_type;
462 	struct imsgbuf ibuf;
463 
464 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
465 	if (datalen != sizeof(iwant))
466 		return got_error(GOT_ERR_PRIVSEP_LEN);
467 	memcpy(&iwant, imsg->data, sizeof(iwant));
468 
469 	memset(&id, 0, sizeof(id));
470 	memcpy(id.sha1, iwant.object_id, SHA1_DIGEST_LENGTH);
471 
472 	if (log_getverbose() > 0 &&
473 	    got_sha1_digest_to_str(id.sha1, hex, sizeof(hex)))
474 		log_debug("client wants %s", hex);
475 
476 	*client = find_client(iwant.client_id);
477 	if (*client == NULL)
478 		return got_error(GOT_ERR_CLIENT_ID);
479 
480 	imsg_init(&ibuf, (*client)->fd);
481 
482 	err = got_object_get_type(&obj_type, repo_read.repo, &id);
483 	if (err)
484 		return err;
485 
486 	if (obj_type != GOT_OBJ_TYPE_COMMIT &&
487 	    obj_type != GOT_OBJ_TYPE_TAG)
488 		return got_error(GOT_ERR_OBJ_TYPE);
489 
490 	err = record_object_id(&(*client)->want_ids, &id);
491 	if (err)
492 		return err;
493 
494 	gotd_imsg_send_ack(&id, &ibuf, PROC_REPO_READ, repo_read.pid);
495 	imsg_clear(&ibuf);
496 	return err;
497 }
498 
499 static const struct got_error *
500 recv_have(struct repo_read_client **client, struct imsg *imsg)
501 {
502 	const struct got_error *err;
503 	struct gotd_imsg_have ihave;
504 	size_t datalen;
505 	char hex[SHA1_DIGEST_STRING_LENGTH];
506 	struct got_object_id id;
507 	int obj_type;
508 	struct imsgbuf ibuf;
509 
510 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
511 	if (datalen != sizeof(ihave))
512 		return got_error(GOT_ERR_PRIVSEP_LEN);
513 	memcpy(&ihave, imsg->data, sizeof(ihave));
514 
515 	memset(&id, 0, sizeof(id));
516 	memcpy(id.sha1, ihave.object_id, SHA1_DIGEST_LENGTH);
517 
518 	if (log_getverbose() > 0 &&
519 	    got_sha1_digest_to_str(id.sha1, hex, sizeof(hex)))
520 		log_debug("client has %s", hex);
521 
522 	*client = find_client(ihave.client_id);
523 	if (*client == NULL)
524 		return got_error(GOT_ERR_CLIENT_ID);
525 
526 	imsg_init(&ibuf, (*client)->fd);
527 
528 	err = got_object_get_type(&obj_type, repo_read.repo, &id);
529 	if (err) {
530 		if (err->code == GOT_ERR_NO_OBJ) {
531 			gotd_imsg_send_nak(&id, &ibuf,
532 			    PROC_REPO_READ, repo_read.pid);
533 			err = NULL;
534 		}
535 		goto done;
536 	}
537 
538 	if (obj_type != GOT_OBJ_TYPE_COMMIT &&
539 	    obj_type != GOT_OBJ_TYPE_TAG) {
540 		gotd_imsg_send_nak(&id, &ibuf, PROC_REPO_READ, repo_read.pid);
541 		err = got_error(GOT_ERR_OBJ_TYPE);
542 		goto done;
543 	}
544 
545 	err = record_object_id(&(*client)->have_ids, &id);
546 	if (err)
547 		return err;
548 
549 	gotd_imsg_send_ack(&id, &ibuf, PROC_REPO_READ, repo_read.pid);
550 done:
551 	imsg_clear(&ibuf);
552 	return err;
553 }
554 
555 struct repo_read_pack_progress_arg {
556 	int report_progress;
557 	struct imsgbuf *ibuf;
558 	int sent_ready;
559 };
560 
561 static const struct got_error *
562 pack_progress(void *arg, int ncolored, int nfound, int ntrees,
563     off_t packfile_size, int ncommits, int nobj_total, int nobj_deltify,
564     int nobj_written)
565 {
566 	struct repo_read_pack_progress_arg *a = arg;
567 	struct gotd_imsg_packfile_progress iprog;
568 	int ret;
569 
570 	if (!a->report_progress)
571 		return NULL;
572 	if (packfile_size > 0 && a->sent_ready)
573 		return NULL;
574 
575 	memset(&iprog, 0, sizeof(iprog));
576 	iprog.ncolored = ncolored;
577 	iprog.nfound = nfound;
578 	iprog.ntrees = ntrees;
579 	iprog.packfile_size = packfile_size;
580 	iprog.ncommits = ncommits;
581 	iprog.nobj_total = nobj_total;
582 	iprog.nobj_deltify = nobj_deltify;
583 	iprog.nobj_written = nobj_written;
584 
585 	/* Using synchronous writes since we are blocking the event loop. */
586 	if (packfile_size == 0) {
587 		ret = imsg_compose(a->ibuf, GOTD_IMSG_PACKFILE_PROGRESS,
588 		    PROC_REPO_READ, repo_read.pid, -1, &iprog, sizeof(iprog));
589 		if (ret == -1) {
590 			return got_error_from_errno("imsg compose "
591 			    "PACKFILE_PROGRESS");
592 		}	
593 	} else {
594 		a->sent_ready = 1;
595 		ret = imsg_compose(a->ibuf, GOTD_IMSG_PACKFILE_READY,
596 		    PROC_REPO_READ, repo_read.pid, -1, &iprog, sizeof(iprog));
597 		if (ret == -1) {
598 			return got_error_from_errno("imsg compose "
599 			    "PACKFILE_READY");
600 		}
601 	}
602 
603 	return gotd_imsg_flush(a->ibuf);
604 }
605 
606 static const struct got_error *
607 receive_delta_cache_fd(struct repo_read_client **client, struct imsg *imsg,
608     struct gotd_imsgev *iev)
609 {
610 	struct gotd_imsg_send_packfile ireq;
611 	size_t datalen;
612 
613 	log_debug("receving delta cache file");
614 
615 	if (imsg->fd == -1)
616 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
617 
618 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
619 	if (datalen != sizeof(ireq))
620 		return got_error(GOT_ERR_PRIVSEP_LEN);
621 	memcpy(&ireq, imsg->data, sizeof(ireq));
622 
623 	*client = find_client(ireq.client_id);
624 	if (*client == NULL)
625 		return got_error(GOT_ERR_CLIENT_ID);
626 
627 	if ((*client)->delta_cache_fd != -1)
628 		return got_error(GOT_ERR_PRIVSEP_MSG);
629 
630 	(*client)->delta_cache_fd = imsg->fd;
631 	(*client)->report_progress = ireq.report_progress;
632 	return NULL;
633 }
634 
635 static const struct got_error *
636 receive_pack_pipe(struct repo_read_client **client, struct imsg *imsg,
637     struct gotd_imsgev *iev)
638 {
639 	struct gotd_imsg_packfile_pipe ireq;
640 	size_t datalen;
641 
642 	log_debug("receving pack pipe descriptor");
643 
644 	if (imsg->fd == -1)
645 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
646 
647 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
648 	if (datalen != sizeof(ireq))
649 		return got_error(GOT_ERR_PRIVSEP_LEN);
650 	memcpy(&ireq, imsg->data, sizeof(ireq));
651 
652 	*client = find_client(ireq.client_id);
653 	if (*client == NULL)
654 		return got_error(GOT_ERR_CLIENT_ID);
655 	if ((*client)->pack_pipe != -1)
656 		return got_error(GOT_ERR_PRIVSEP_MSG);
657 
658 	(*client)->pack_pipe = imsg->fd;
659 	return NULL;
660 }
661 
662 static const struct got_error *
663 send_packfile(struct repo_read_client *client, struct imsg *imsg,
664     struct gotd_imsgev *iev)
665 {
666 	const struct got_error *err = NULL;
667 	struct gotd_imsg_packfile_done idone;
668 	uint8_t packsha1[SHA1_DIGEST_LENGTH];
669 	char hex[SHA1_DIGEST_STRING_LENGTH];
670 	FILE *delta_cache = NULL;
671 	struct imsgbuf ibuf;
672 	struct repo_read_pack_progress_arg pa;
673 	struct got_ratelimit rl;
674 
675 	log_debug("packfile request received");
676 
677 	got_ratelimit_init(&rl, 2, 0);
678 
679 	if (client->delta_cache_fd == -1 || client->pack_pipe == -1)
680 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
681 
682 	imsg_init(&ibuf, client->fd);
683 
684 	delta_cache = fdopen(client->delta_cache_fd, "w+");
685 	if (delta_cache == NULL) {
686 		err = got_error_from_errno("fdopen");
687 		goto done;
688 	}
689 	client->delta_cache_fd = -1;
690 
691 	memset(&pa, 0, sizeof(pa));
692 	pa.ibuf = &ibuf;
693 	pa.report_progress = client->report_progress;
694 
695 	err = got_pack_create(packsha1, client->pack_pipe, delta_cache,
696 	    client->have_ids.ids, client->have_ids.nids,
697 	    client->want_ids.ids, client->want_ids.nids,
698 	    repo_read.repo, 0, 1, pack_progress, &pa, &rl,
699 	    check_cancelled, NULL);
700 	if (err)
701 		goto done;
702 	
703 	if (log_getverbose() > 0 &&
704 	    got_sha1_digest_to_str(packsha1, hex, sizeof(hex)))
705 		log_debug("sent pack-%s.pack", hex);
706 
707 	memset(&idone, 0, sizeof(idone));
708 	idone.client_id = client->id;
709 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_PACKFILE_DONE,
710 	    PROC_REPO_READ, -1, &idone, sizeof(idone)) == -1)
711 		err = got_error_from_errno("imsg compose PACKFILE_DONE");
712 done:
713 	if (delta_cache != NULL && fclose(delta_cache) == EOF && err == NULL)
714 		err = got_error_from_errno("fclose");
715 	imsg_clear(&ibuf);
716 	return err;
717 }
718 
719 static const struct got_error *
720 recv_disconnect(struct imsg *imsg)
721 {
722 	const struct got_error *err = NULL;
723 	struct gotd_imsg_disconnect idisconnect;
724 	size_t datalen;
725 	int client_fd, delta_cache_fd, pack_pipe;
726 	struct repo_read_client *client = NULL;
727 	uint64_t slot;
728 
729 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
730 	if (datalen != sizeof(idisconnect))
731 		return got_error(GOT_ERR_PRIVSEP_LEN);
732 	memcpy(&idisconnect, imsg->data, sizeof(idisconnect));
733 
734 	log_debug("client disconnecting");
735 
736 	client = find_client(idisconnect.client_id);
737 	if (client == NULL)
738 		return got_error(GOT_ERR_CLIENT_ID);
739 
740 	slot = client_hash(client->id) % nitems(repo_read_clients);
741 	STAILQ_REMOVE(&repo_read_clients[slot], client, repo_read_client,
742 	    entry);
743 	free_object_ids(&client->have_ids);
744 	free_object_ids(&client->want_ids);
745 	client_fd = client->fd;
746 	delta_cache_fd = client->delta_cache_fd;
747 	pack_pipe = client->pack_pipe;
748 	free(client);
749 	if (close(client_fd) == -1)
750 		err = got_error_from_errno("close");
751 	if (delta_cache_fd != -1 && close(delta_cache_fd) == -1 && err == NULL)
752 		return got_error_from_errno("close");
753 	if (pack_pipe != -1 && close(pack_pipe) == -1 && err == NULL)
754 		return got_error_from_errno("close");
755 	return err;
756 }
757 
758 static void
759 repo_read_dispatch(int fd, short event, void *arg)
760 {
761 	const struct got_error *err = NULL;
762 	struct gotd_imsgev *iev = arg;
763 	struct imsgbuf *ibuf = &iev->ibuf;
764 	struct imsg imsg;
765 	ssize_t n;
766 	int shut = 0;
767 	struct repo_read_client *client = NULL;
768 
769 	if (event & EV_READ) {
770 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
771 			fatal("imsg_read error");
772 		if (n == 0)	/* Connection closed. */
773 			shut = 1;
774 	}
775 
776 	if (event & EV_WRITE) {
777 		n = msgbuf_write(&ibuf->w);
778 		if (n == -1 && errno != EAGAIN)
779 			fatal("msgbuf_write");
780 		if (n == 0)	/* Connection closed. */
781 			shut = 1;
782 	}
783 
784 	while (err == NULL && check_cancelled(NULL) == NULL) {
785 		client = NULL;
786 		if ((n = imsg_get(ibuf, &imsg)) == -1)
787 			fatal("%s: imsg_get", __func__);
788 		if (n == 0)	/* No more messages. */
789 			break;
790 
791 		switch (imsg.hdr.type) {
792 		case GOTD_IMSG_LIST_REFS_INTERNAL:
793 			err = list_refs(&client, &imsg);
794 			if (err)
795 				log_warnx("%s: ls-refs: %s", repo_read.title,
796 				    err->msg);
797 			break;
798 		case GOTD_IMSG_WANT:
799 			err = recv_want(&client, &imsg);
800 			if (err)
801 				log_warnx("%s: want-line: %s", repo_read.title,
802 				    err->msg);
803 			break;
804 		case GOTD_IMSG_HAVE:
805 			err = recv_have(&client, &imsg);
806 			if (err)
807 				log_warnx("%s: have-line: %s", repo_read.title,
808 				    err->msg);
809 			break;
810 		case GOTD_IMSG_SEND_PACKFILE:
811 			err = receive_delta_cache_fd(&client, &imsg, iev);
812 			if (err)
813 				log_warnx("%s: receiving delta cache: %s",
814 				    repo_read.title, err->msg);
815 			break;
816 		case GOTD_IMSG_PACKFILE_PIPE:
817 			err = receive_pack_pipe(&client, &imsg, iev);
818 			if (err) {
819 				log_warnx("%s: receiving pack pipe: %s",
820 				    repo_read.title, err->msg);
821 				break;
822 			}
823 			if (client->pack_pipe == -1)
824 				break;
825 			err = send_packfile(client, &imsg, iev);
826 			if (err)
827 				log_warnx("%s: sending packfile: %s",
828 				    repo_read.title, err->msg);
829 			break;
830 		case GOTD_IMSG_DISCONNECT:
831 			err = recv_disconnect(&imsg);
832 			if (err)
833 				log_warnx("%s: disconnect: %s",
834 				    repo_read.title, err->msg);
835 			break;
836 		default:
837 			log_debug("%s: unexpected imsg %d", repo_read.title,
838 			    imsg.hdr.type);
839 			break;
840 		}
841 
842 		imsg_free(&imsg);
843 	}
844 
845 	if (!shut && check_cancelled(NULL) == NULL) {
846 		if (err &&
847 		    gotd_imsg_send_error_event(iev, PROC_REPO_READ,
848 		        client ? client->id : 0, err) == -1) {
849 			log_warnx("could not send error to parent: %s",
850 			    err->msg);
851 		}
852 		gotd_imsg_event_add(iev);
853 	} else {
854 		/* This pipe is dead. Remove its event handler */
855 		event_del(&iev->ev);
856 		event_loopexit(NULL);
857 	}
858 }
859 
860 void
861 repo_read_main(const char *title, const char *repo_path,
862     int *pack_fds, int *temp_fds)
863 {
864 	const struct got_error *err = NULL;
865 	struct gotd_imsgev iev;
866 
867 	repo_read.title = title;
868 	repo_read.pid = getpid();
869 	repo_read.pack_fds = pack_fds;
870 	repo_read.temp_fds = temp_fds;
871 
872 	arc4random_buf(&clients_hash_key, sizeof(clients_hash_key));
873 
874 	err = got_repo_open(&repo_read.repo, repo_path, NULL, pack_fds);
875 	if (err)
876 		goto done;
877 	if (!got_repo_is_bare(repo_read.repo)) {
878 		err = got_error_msg(GOT_ERR_NOT_GIT_REPO,
879 		    "bare git repository required");
880 		goto done;
881 	}
882 
883 	got_repo_temp_fds_set(repo_read.repo, temp_fds);
884 
885 	signal(SIGINT, catch_sigint);
886 	signal(SIGTERM, catch_sigterm);
887 	signal(SIGPIPE, SIG_IGN);
888 	signal(SIGHUP, SIG_IGN);
889 
890 	imsg_init(&iev.ibuf, GOTD_FILENO_MSG_PIPE);
891 	iev.handler = repo_read_dispatch;
892 	iev.events = EV_READ;
893 	iev.handler_arg = NULL;
894 	event_set(&iev.ev, iev.ibuf.fd, EV_READ, repo_read_dispatch, &iev);
895 	if (event_add(&iev.ev, NULL) == -1) {
896 		err = got_error_from_errno("event_add");
897 		goto done;
898 	}
899 
900 	event_dispatch();
901 done:
902 	if (err)
903 		log_warnx("%s: %s", title, err->msg);
904 	repo_read_shutdown();
905 }
906 
907 void
908 repo_read_shutdown(void)
909 {
910 	log_debug("%s: shutting down", repo_read.title);
911 	if (repo_read.repo)
912 		got_repo_close(repo_read.repo);
913 	got_repo_pack_fds_close(repo_read.pack_fds);
914 	got_repo_temp_fds_close(repo_read.temp_fds);
915 	exit(0);
916 }