Game of Trees Repos

Blob

Date:: Tue Jan 10 12:02:48 2023 UTC
Message:: add a gotd session process, split off from the parent process The new session process is able to manipulate files in the repository and keeps track of the read/write client session state. The parent process now restricts its view of the filesystem to the absolute path stored in argv[0], and combines this with unveil "x" on this path. As a result the parent process can only re-exec itself. small tweaks + 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 <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 	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 gotd_object_id_array	 want_ids;
74 	struct gotd_object_id_array	 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 	client->delta_cache_fd = -1;
290 	client->pack_pipe = -1;
291 
292 	imsg_init(&ibuf, client_fd);
293 
294 	err = got_ref_list(&refs, repo_read.repo, "",
295 	    got_ref_cmp_by_name, NULL);
296 	if (err)
297 		return err;
298 
299 	memset(&irefs, 0, sizeof(irefs));
300 	TAILQ_FOREACH(re, &refs, entry) {
301 		struct got_object_id *id;
302 		int obj_type;
303 
304 		if (got_ref_is_symbolic(re->ref)) {
305 			const char *refname = got_ref_get_name(re->ref);
306 			if (strcmp(refname, GOT_REF_HEAD) != 0)
307 				continue;
308 			err = got_ref_resolve(&head_target_id, repo_read.repo,
309 			    re->ref);
310 			if (err) {
311 				if (err->code != GOT_ERR_NOT_REF)
312 					return err;
313 				/*
314 				 * HEAD points to a non-existent branch.
315 				 * Do not advertise it.
316 				 * Matches git-daemon's behaviour.
317 				 */
318 				head_target_id = NULL;
319 				err = NULL;
320 			} else
321 				irefs.nrefs++;
322 			continue;
323 		}
324 
325 		irefs.nrefs++;
326 
327 		/* Account for a peeled tag refs. */
328 		err = got_ref_resolve(&id, repo_read.repo, re->ref);
329 		if (err)
330 			goto done;
331 		err = got_object_get_type(&obj_type, repo_read.repo, id);	
332 		free(id);
333 		if (err)
334 			goto done;
335 		if (obj_type == GOT_OBJ_TYPE_TAG)
336 			irefs.nrefs++;
337 	}
338 
339 	if (imsg_compose(&ibuf, GOTD_IMSG_REFLIST, PROC_REPO_READ,
340 	    repo_read.pid, -1, &irefs, sizeof(irefs)) == -1) {
341 		err = got_error_from_errno("imsg_compose REFLIST");
342 		goto done;
343 	}
344 
345 	/*
346 	 * Send the HEAD symref first. In Git-protocol versions < 2
347 	 * the HEAD symref must be announced on the initial line of
348 	 * the server's ref advertisement.
349 	 * For now, we do not advertise symrefs other than HEAD.
350 	 */
351 	TAILQ_FOREACH(re, &refs, entry) {
352 		if (!got_ref_is_symbolic(re->ref) ||
353 		    strcmp(got_ref_get_name(re->ref), GOT_REF_HEAD) != 0 ||
354 		    head_target_id == NULL)
355 			continue;
356 		err = send_symref(re->ref, head_target_id, &ibuf);
357 		if (err)
358 			goto done;
359 		break;
360 	}
361 	TAILQ_FOREACH(re, &refs, entry) {
362 		if (got_ref_is_symbolic(re->ref))
363 			continue;
364 		err = send_ref(re->ref, &ibuf);
365 		if (err)
366 			goto done;
367 	}
368 
369 	err = gotd_imsg_flush(&ibuf);
370 done:
371 	got_ref_list_free(&refs);
372 	imsg_clear(&ibuf);
373 	return err;
374 }
375 
376 static const struct got_error *
377 record_object_id(struct gotd_object_id_array *array, struct got_object_id *id)
378 {
379 	const size_t alloc_chunksz = 256;
380 
381 	if (array->ids == NULL) {
382 		array->ids = reallocarray(NULL, alloc_chunksz,
383 		    sizeof(*array->ids));
384 		if (array->ids == NULL)
385 			return got_error_from_errno("reallocarray");
386 		array->nalloc = alloc_chunksz;
387 		array->nids = 0;
388 	} else if (array->nalloc <= array->nids) {
389 		struct got_object_id **new;
390 		new = recallocarray(array->ids, array->nalloc,
391 		    array->nalloc + alloc_chunksz, sizeof(*new));
392 		if (new == NULL)
393 			return got_error_from_errno("recallocarray");
394 		array->ids = new;
395 		array->nalloc += alloc_chunksz;
396 	}
397 
398 	array->ids[array->nids] = got_object_id_dup(id);
399 	if (array->ids[array->nids] == NULL)
400 		return got_error_from_errno("got_object_id_dup");
401 	array->nids++;
402 	return NULL;
403 }
404 
405 static void
406 free_object_ids(struct gotd_object_id_array *array)
407 {
408 	size_t i;
409 
410 	for (i = 0; i < array->nids; i++)
411 		free(array->ids[i]);
412 	free(array->ids);
413 
414 	array->ids = NULL;
415 	array->nalloc = 0;
416 	array->nids = 0;
417 }
418 
419 static const struct got_error *
420 recv_want(struct imsg *imsg)
421 {
422 	const struct got_error *err;
423 	struct repo_read_client *client = &repo_read_client;
424 	struct gotd_imsg_want iwant;
425 	size_t datalen;
426 	char hex[SHA1_DIGEST_STRING_LENGTH];
427 	struct got_object_id id;
428 	int obj_type;
429 	struct imsgbuf ibuf;
430 
431 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
432 	if (datalen != sizeof(iwant))
433 		return got_error(GOT_ERR_PRIVSEP_LEN);
434 	memcpy(&iwant, imsg->data, sizeof(iwant));
435 
436 	memset(&id, 0, sizeof(id));
437 	memcpy(id.sha1, iwant.object_id, SHA1_DIGEST_LENGTH);
438 
439 	if (log_getverbose() > 0 &&
440 	    got_sha1_digest_to_str(id.sha1, hex, sizeof(hex)))
441 		log_debug("client wants %s", hex);
442 
443 	imsg_init(&ibuf, client->fd);
444 
445 	err = got_object_get_type(&obj_type, repo_read.repo, &id);
446 	if (err)
447 		return err;
448 
449 	if (obj_type != GOT_OBJ_TYPE_COMMIT &&
450 	    obj_type != GOT_OBJ_TYPE_TAG)
451 		return got_error(GOT_ERR_OBJ_TYPE);
452 
453 	err = record_object_id(&client->want_ids, &id);
454 	if (err)
455 		return err;
456 
457 	gotd_imsg_send_ack(&id, &ibuf, PROC_REPO_READ, repo_read.pid);
458 	imsg_clear(&ibuf);
459 	return err;
460 }
461 
462 static const struct got_error *
463 recv_have(struct imsg *imsg)
464 {
465 	const struct got_error *err;
466 	struct repo_read_client *client = &repo_read_client;
467 	struct gotd_imsg_have ihave;
468 	size_t datalen;
469 	char hex[SHA1_DIGEST_STRING_LENGTH];
470 	struct got_object_id id;
471 	int obj_type;
472 	struct imsgbuf ibuf;
473 
474 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
475 	if (datalen != sizeof(ihave))
476 		return got_error(GOT_ERR_PRIVSEP_LEN);
477 	memcpy(&ihave, imsg->data, sizeof(ihave));
478 
479 	memset(&id, 0, sizeof(id));
480 	memcpy(id.sha1, ihave.object_id, SHA1_DIGEST_LENGTH);
481 
482 	if (log_getverbose() > 0 &&
483 	    got_sha1_digest_to_str(id.sha1, hex, sizeof(hex)))
484 		log_debug("client has %s", hex);
485 
486 	imsg_init(&ibuf, client->fd);
487 
488 	err = got_object_get_type(&obj_type, repo_read.repo, &id);
489 	if (err) {
490 		if (err->code == GOT_ERR_NO_OBJ) {
491 			gotd_imsg_send_nak(&id, &ibuf,
492 			    PROC_REPO_READ, repo_read.pid);
493 			err = NULL;
494 		}
495 		goto done;
496 	}
497 
498 	if (obj_type != GOT_OBJ_TYPE_COMMIT &&
499 	    obj_type != GOT_OBJ_TYPE_TAG) {
500 		gotd_imsg_send_nak(&id, &ibuf, PROC_REPO_READ, repo_read.pid);
501 		err = got_error(GOT_ERR_OBJ_TYPE);
502 		goto done;
503 	}
504 
505 	err = record_object_id(&client->have_ids, &id);
506 	if (err)
507 		return err;
508 
509 	gotd_imsg_send_ack(&id, &ibuf, PROC_REPO_READ, repo_read.pid);
510 done:
511 	imsg_clear(&ibuf);
512 	return err;
513 }
514 
515 struct repo_read_pack_progress_arg {
516 	int report_progress;
517 	struct imsgbuf *ibuf;
518 	int sent_ready;
519 };
520 
521 static const struct got_error *
522 pack_progress(void *arg, int ncolored, int nfound, int ntrees,
523     off_t packfile_size, int ncommits, int nobj_total, int nobj_deltify,
524     int nobj_written)
525 {
526 	struct repo_read_pack_progress_arg *a = arg;
527 	struct gotd_imsg_packfile_progress iprog;
528 	int ret;
529 
530 	if (!a->report_progress)
531 		return NULL;
532 	if (packfile_size > 0 && a->sent_ready)
533 		return NULL;
534 
535 	memset(&iprog, 0, sizeof(iprog));
536 	iprog.ncolored = ncolored;
537 	iprog.nfound = nfound;
538 	iprog.ntrees = ntrees;
539 	iprog.packfile_size = packfile_size;
540 	iprog.ncommits = ncommits;
541 	iprog.nobj_total = nobj_total;
542 	iprog.nobj_deltify = nobj_deltify;
543 	iprog.nobj_written = nobj_written;
544 
545 	/* Using synchronous writes since we are blocking the event loop. */
546 	if (packfile_size == 0) {
547 		ret = imsg_compose(a->ibuf, GOTD_IMSG_PACKFILE_PROGRESS,
548 		    PROC_REPO_READ, repo_read.pid, -1, &iprog, sizeof(iprog));
549 		if (ret == -1) {
550 			return got_error_from_errno("imsg compose "
551 			    "PACKFILE_PROGRESS");
552 		}	
553 	} else {
554 		a->sent_ready = 1;
555 		ret = imsg_compose(a->ibuf, GOTD_IMSG_PACKFILE_READY,
556 		    PROC_REPO_READ, repo_read.pid, -1, &iprog, sizeof(iprog));
557 		if (ret == -1) {
558 			return got_error_from_errno("imsg compose "
559 			    "PACKFILE_READY");
560 		}
561 	}
562 
563 	return gotd_imsg_flush(a->ibuf);
564 }
565 
566 static const struct got_error *
567 receive_delta_cache_fd(struct imsg *imsg,
568     struct gotd_imsgev *iev)
569 {
570 	struct repo_read_client *client = &repo_read_client;
571 	struct gotd_imsg_send_packfile ireq;
572 	size_t datalen;
573 
574 	log_debug("receving delta cache file");
575 
576 	if (imsg->fd == -1)
577 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
578 
579 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
580 	if (datalen != sizeof(ireq))
581 		return got_error(GOT_ERR_PRIVSEP_LEN);
582 	memcpy(&ireq, imsg->data, sizeof(ireq));
583 
584 	if (client->delta_cache_fd != -1)
585 		return got_error(GOT_ERR_PRIVSEP_MSG);
586 
587 	client->delta_cache_fd = imsg->fd;
588 	client->report_progress = ireq.report_progress;
589 	return NULL;
590 }
591 
592 static const struct got_error *
593 receive_pack_pipe(struct imsg *imsg, struct gotd_imsgev *iev)
594 {
595 	struct repo_read_client *client = &repo_read_client;
596 	struct gotd_imsg_packfile_pipe ireq;
597 	size_t datalen;
598 
599 	log_debug("receving pack pipe descriptor");
600 
601 	if (imsg->fd == -1)
602 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
603 
604 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
605 	if (datalen != sizeof(ireq))
606 		return got_error(GOT_ERR_PRIVSEP_LEN);
607 	memcpy(&ireq, imsg->data, sizeof(ireq));
608 
609 	if (client->pack_pipe != -1)
610 		return got_error(GOT_ERR_PRIVSEP_MSG);
611 
612 	client->pack_pipe = imsg->fd;
613 	return NULL;
614 }
615 
616 static const struct got_error *
617 send_packfile(struct imsg *imsg, struct gotd_imsgev *iev)
618 {
619 	const struct got_error *err = NULL;
620 	struct repo_read_client *client = &repo_read_client;
621 	struct gotd_imsg_packfile_done idone;
622 	uint8_t packsha1[SHA1_DIGEST_LENGTH];
623 	char hex[SHA1_DIGEST_STRING_LENGTH];
624 	FILE *delta_cache = NULL;
625 	struct imsgbuf ibuf;
626 	struct repo_read_pack_progress_arg pa;
627 	struct got_ratelimit rl;
628 
629 	log_debug("packfile request received");
630 
631 	got_ratelimit_init(&rl, 2, 0);
632 
633 	if (client->delta_cache_fd == -1 || client->pack_pipe == -1)
634 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
635 
636 	imsg_init(&ibuf, client->fd);
637 
638 	delta_cache = fdopen(client->delta_cache_fd, "w+");
639 	if (delta_cache == NULL) {
640 		err = got_error_from_errno("fdopen");
641 		goto done;
642 	}
643 	client->delta_cache_fd = -1;
644 
645 	memset(&pa, 0, sizeof(pa));
646 	pa.ibuf = &ibuf;
647 	pa.report_progress = client->report_progress;
648 
649 	err = got_pack_create(packsha1, client->pack_pipe, delta_cache,
650 	    client->have_ids.ids, client->have_ids.nids,
651 	    client->want_ids.ids, client->want_ids.nids,
652 	    repo_read.repo, 0, 1, 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 	return err;
671 }
672 
673 static const struct got_error *
674 recv_disconnect(struct imsg *imsg)
675 {
676 	const struct got_error *err = NULL;
677 	struct gotd_imsg_disconnect idisconnect;
678 	size_t datalen;
679 	int delta_cache_fd, pack_pipe;
680 	struct repo_read_client *client = &repo_read_client;
681 
682 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
683 	if (datalen != sizeof(idisconnect))
684 		return got_error(GOT_ERR_PRIVSEP_LEN);
685 	memcpy(&idisconnect, imsg->data, sizeof(idisconnect));
686 
687 	log_debug("client disconnecting");
688 
689 	free_object_ids(&client->have_ids);
690 	free_object_ids(&client->want_ids);
691 	if (close(client->fd) == -1)
692 		err = got_error_from_errno("close");
693 	delta_cache_fd = client->delta_cache_fd;
694 	if (delta_cache_fd != -1 && close(delta_cache_fd) == -1 && err == NULL)
695 		return got_error_from_errno("close");
696 	pack_pipe = client->pack_pipe;
697 	if (pack_pipe != -1 && close(pack_pipe) == -1 && err == NULL)
698 		return got_error_from_errno("close");
699 	return err;
700 }
701 
702 static void
703 repo_read_dispatch_session(int fd, short event, void *arg)
704 {
705 	const struct got_error *err = NULL;
706 	struct gotd_imsgev *iev = arg;
707 	struct imsgbuf *ibuf = &iev->ibuf;
708 	struct imsg imsg;
709 	ssize_t n;
710 	int shut = 0;
711 	struct repo_read_client *client = &repo_read_client;
712 
713 	if (event & EV_READ) {
714 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
715 			fatal("imsg_read error");
716 		if (n == 0)	/* Connection closed. */
717 			shut = 1;
718 	}
719 
720 	if (event & EV_WRITE) {
721 		n = msgbuf_write(&ibuf->w);
722 		if (n == -1 && errno != EAGAIN)
723 			fatal("msgbuf_write");
724 		if (n == 0)	/* Connection closed. */
725 			shut = 1;
726 	}
727 
728 	while (err == NULL && check_cancelled(NULL) == NULL) {
729 		if ((n = imsg_get(ibuf, &imsg)) == -1)
730 			fatal("%s: imsg_get", __func__);
731 		if (n == 0)	/* No more messages. */
732 			break;
733 
734 		if (imsg.hdr.type != GOTD_IMSG_LIST_REFS_INTERNAL &&
735 		    client->id == 0) {
736 			err = got_error(GOT_ERR_PRIVSEP_MSG);
737 			break;
738 		}
739 
740 		switch (imsg.hdr.type) {
741 		case GOTD_IMSG_LIST_REFS_INTERNAL:
742 			err = list_refs(&imsg);
743 			if (err)
744 				log_warnx("%s: ls-refs: %s", repo_read.title,
745 				    err->msg);
746 			break;
747 		case GOTD_IMSG_WANT:
748 			err = recv_want(&imsg);
749 			if (err)
750 				log_warnx("%s: want-line: %s", repo_read.title,
751 				    err->msg);
752 			break;
753 		case GOTD_IMSG_HAVE:
754 			err = recv_have(&imsg);
755 			if (err)
756 				log_warnx("%s: have-line: %s", repo_read.title,
757 				    err->msg);
758 			break;
759 		case GOTD_IMSG_SEND_PACKFILE:
760 			err = receive_delta_cache_fd(&imsg, iev);
761 			if (err)
762 				log_warnx("%s: receiving delta cache: %s",
763 				    repo_read.title, err->msg);
764 			break;
765 		case GOTD_IMSG_PACKFILE_PIPE:
766 			err = receive_pack_pipe(&imsg, iev);
767 			if (err) {
768 				log_warnx("%s: receiving pack pipe: %s",
769 				    repo_read.title, err->msg);
770 				break;
771 			}
772 			err = send_packfile(&imsg, iev);
773 			if (err)
774 				log_warnx("%s: sending packfile: %s",
775 				    repo_read.title, err->msg);
776 			break;
777 		case GOTD_IMSG_DISCONNECT:
778 			err = recv_disconnect(&imsg);
779 			if (err)
780 				log_warnx("%s: disconnect: %s",
781 				    repo_read.title, err->msg);
782 			shut = 1;
783 			break;
784 		default:
785 			log_debug("%s: unexpected imsg %d", repo_read.title,
786 			    imsg.hdr.type);
787 			break;
788 		}
789 
790 		imsg_free(&imsg);
791 	}
792 
793 	if (!shut && check_cancelled(NULL) == NULL) {
794 		if (err &&
795 		    gotd_imsg_send_error_event(iev, PROC_REPO_READ,
796 		        client->id, err) == -1) {
797 			log_warnx("could not send error to parent: %s",
798 			    err->msg);
799 		}
800 		gotd_imsg_event_add(iev);
801 	} else {
802 		/* This pipe is dead. Remove its event handler */
803 		event_del(&iev->ev);
804 		event_loopexit(NULL);
805 	}
806 }
807 
808 static const struct got_error *
809 recv_connect(struct imsg *imsg)
810 {
811 	struct gotd_imsgev *iev = &repo_read.session_iev;
812 	size_t datalen;
813 
814 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
815 	if (datalen != 0)
816 		return got_error(GOT_ERR_PRIVSEP_LEN);
817 	if (imsg->fd == -1)
818 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
819 
820 	if (repo_read.session_fd != -1)
821 		return got_error(GOT_ERR_PRIVSEP_MSG);
822 
823 	repo_read.session_fd = imsg->fd;
824 
825 	imsg_init(&iev->ibuf, repo_read.session_fd);
826 	iev->handler = repo_read_dispatch_session;
827 	iev->events = EV_READ;
828 	iev->handler_arg = NULL;
829 	event_set(&iev->ev, iev->ibuf.fd, EV_READ,
830 	    repo_read_dispatch_session, iev);
831 	gotd_imsg_event_add(iev);
832 
833 	return NULL;
834 }
835 
836 static void
837 repo_read_dispatch(int fd, short event, void *arg)
838 {
839 	const struct got_error *err = NULL;
840 	struct gotd_imsgev *iev = arg;
841 	struct imsgbuf *ibuf = &iev->ibuf;
842 	struct imsg imsg;
843 	ssize_t n;
844 	int shut = 0;
845 	struct repo_read_client *client = &repo_read_client;
846 
847 	if (event & EV_READ) {
848 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
849 			fatal("imsg_read error");
850 		if (n == 0)	/* Connection closed. */
851 			shut = 1;
852 	}
853 
854 	if (event & EV_WRITE) {
855 		n = msgbuf_write(&ibuf->w);
856 		if (n == -1 && errno != EAGAIN)
857 			fatal("msgbuf_write");
858 		if (n == 0)	/* Connection closed. */
859 			shut = 1;
860 	}
861 
862 	while (err == NULL && check_cancelled(NULL) == NULL) {
863 		if ((n = imsg_get(ibuf, &imsg)) == -1)
864 			fatal("%s: imsg_get", __func__);
865 		if (n == 0)	/* No more messages. */
866 			break;
867 
868 		switch (imsg.hdr.type) {
869 		case GOTD_IMSG_CONNECT_REPO_CHILD:
870 			err = recv_connect(&imsg);
871 			break;
872 		default:
873 			log_debug("%s: unexpected imsg %d", repo_read.title,
874 			    imsg.hdr.type);
875 			break;
876 		}
877 
878 		imsg_free(&imsg);
879 	}
880 
881 	if (!shut && check_cancelled(NULL) == NULL) {
882 		if (err &&
883 		    gotd_imsg_send_error_event(iev, PROC_REPO_READ,
884 		        client->id, err) == -1) {
885 			log_warnx("could not send error to parent: %s",
886 			    err->msg);
887 		}
888 		gotd_imsg_event_add(iev);
889 	} else {
890 		/* This pipe is dead. Remove its event handler */
891 		event_del(&iev->ev);
892 		event_loopexit(NULL);
893 	}
894 }
895 
896 void
897 repo_read_main(const char *title, const char *repo_path,
898     int *pack_fds, int *temp_fds)
899 {
900 	const struct got_error *err = NULL;
901 	struct gotd_imsgev iev;
902 
903 	repo_read.title = title;
904 	repo_read.pid = getpid();
905 	repo_read.pack_fds = pack_fds;
906 	repo_read.temp_fds = temp_fds;
907 	repo_read.session_fd = -1;
908 	repo_read.session_iev.ibuf.fd = -1;
909 
910 	err = got_repo_open(&repo_read.repo, repo_path, NULL, pack_fds);
911 	if (err)
912 		goto done;
913 	if (!got_repo_is_bare(repo_read.repo)) {
914 		err = got_error_msg(GOT_ERR_NOT_GIT_REPO,
915 		    "bare git repository required");
916 		goto done;
917 	}
918 
919 	got_repo_temp_fds_set(repo_read.repo, temp_fds);
920 
921 	signal(SIGINT, catch_sigint);
922 	signal(SIGTERM, catch_sigterm);
923 	signal(SIGPIPE, SIG_IGN);
924 	signal(SIGHUP, SIG_IGN);
925 
926 	imsg_init(&iev.ibuf, GOTD_FILENO_MSG_PIPE);
927 	iev.handler = repo_read_dispatch;
928 	iev.events = EV_READ;
929 	iev.handler_arg = NULL;
930 	event_set(&iev.ev, iev.ibuf.fd, EV_READ, repo_read_dispatch, &iev);
931 
932 	if (gotd_imsg_compose_event(&iev, GOTD_IMSG_REPO_CHILD_READY,
933 	    PROC_REPO_READ, -1, NULL, 0) == -1) {
934 		err = got_error_from_errno("imsg compose REPO_CHILD_READY");
935 		goto done;
936 	}
937 
938 	event_dispatch();
939 done:
940 	if (err)
941 		log_warnx("%s: %s", title, err->msg);
942 	repo_read_shutdown();
943 }
944 
945 void
946 repo_read_shutdown(void)
947 {
948 	log_debug("%s: shutting down", repo_read.title);
949 	if (repo_read.repo)
950 		got_repo_close(repo_read.repo);
951 	got_repo_pack_fds_close(repo_read.pack_fds);
952 	got_repo_temp_fds_close(repo_read.temp_fds);
953 	if (repo_read.session_fd != -1)
954 		close(repo_read.session_fd);
955 	exit(0);
956 }