Game of Trees Repos

Blob

Date:: Sun Dec 31 11:13:28 2023 UTC
Message:: avoid opening objects in the gotd session process for no reason The session process opened an object as part of a sanity check and simply closed it again. Opening an object involves decompression and combination of deltas. Add a new interface which checks whether an object ID exists without such overhead and call it from gotd.
Actions:: History | Blame | Raw File
1 /*
2  * Copyright (c) 2022, 2023 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/tree.h>
20 #include <sys/socket.h>
21 #include <sys/stat.h>
22 #include <sys/uio.h>
23 
24 #include <errno.h>
25 #include <event.h>
26 #include <limits.h>
27 #include <sha1.h>
28 #include <sha2.h>
29 #include <signal.h>
30 #include <stdint.h>
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <string.h>
34 #include <imsg.h>
35 #include <unistd.h>
36 
37 #include "got_error.h"
38 #include "got_repository.h"
39 #include "got_object.h"
40 #include "got_path.h"
41 #include "got_reference.h"
42 #include "got_opentemp.h"
43 
44 #include "got_lib_hash.h"
45 #include "got_lib_delta.h"
46 #include "got_lib_object.h"
47 #include "got_lib_object_cache.h"
48 #include "got_lib_pack.h"
49 #include "got_lib_repository.h"
50 #include "got_lib_gitproto.h"
51 
52 #include "gotd.h"
53 #include "log.h"
54 #include "session.h"
55 
56 
57 static struct gotd_session {
58 	pid_t pid;
59 	const char *title;
60 	struct got_repository *repo;
61 	int *pack_fds;
62 	int *temp_fds;
63 	struct gotd_imsgev parent_iev;
64 	struct timeval request_timeout;
65 	enum gotd_procid proc_id;
66 } gotd_session;
67 
68 static struct gotd_session_client {
69 	enum gotd_session_state		 state;
70 	int				 is_writing;
71 	struct gotd_client_capability	*capabilities;
72 	size_t				 ncapa_alloc;
73 	size_t				 ncapabilities;
74 	uint32_t			 id;
75 	int				 fd;
76 	int				 delta_cache_fd;
77 	struct gotd_imsgev		 iev;
78 	struct gotd_imsgev		 repo_child_iev;
79 	struct event			 tmo;
80 	uid_t				 euid;
81 	gid_t				 egid;
82 	char				*packfile_path;
83 	char				*packidx_path;
84 	int				 nref_updates;
85 	int				 accept_flush_pkt;
86 	int				 flush_disconnect;
87 } gotd_session_client;
88 
89 void gotd_session_sighdlr(int sig, short event, void *arg);
90 static void gotd_session_shutdown(void);
91 
92 static void
93 disconnect(struct gotd_session_client *client)
94 {
95 	log_debug("uid %d: disconnecting", client->euid);
96 
97 	if (gotd_imsg_compose_event(&gotd_session.parent_iev,
98 	    GOTD_IMSG_DISCONNECT, gotd_session.proc_id, -1, NULL, 0) == -1)
99 		log_warn("imsg compose DISCONNECT");
100 
101 	imsg_clear(&client->repo_child_iev.ibuf);
102 	event_del(&client->repo_child_iev.ev);
103 	evtimer_del(&client->tmo);
104 	close(client->fd);
105 	if (client->delta_cache_fd != -1)
106 		close(client->delta_cache_fd);
107 	if (client->packfile_path) {
108 		if (unlink(client->packfile_path) == -1 && errno != ENOENT)
109 			log_warn("unlink %s: ", client->packfile_path);
110 		free(client->packfile_path);
111 	}
112 	if (client->packidx_path) {
113 		if (unlink(client->packidx_path) == -1 && errno != ENOENT)
114 			log_warn("unlink %s: ", client->packidx_path);
115 		free(client->packidx_path);
116 	}
117 	free(client->capabilities);
118 
119 	gotd_session_shutdown();
120 }
121 
122 static void
123 disconnect_on_error(struct gotd_session_client *client,
124     const struct got_error *err)
125 {
126 	struct imsgbuf ibuf;
127 
128 	if (err->code != GOT_ERR_EOF) {
129 		log_warnx("uid %d: %s", client->euid, err->msg);
130 		imsg_init(&ibuf, client->fd);
131 		gotd_imsg_send_error(&ibuf, 0, gotd_session.proc_id, err);
132 		imsg_clear(&ibuf);
133 	}
134 
135 	disconnect(client);
136 }
137 
138 static void
139 gotd_request_timeout(int fd, short events, void *arg)
140 {
141 	struct gotd_session_client *client = arg;
142 
143 	log_debug("disconnecting uid %d due to timeout", client->euid);
144 	disconnect(client);
145 }
146 
147 void
148 gotd_session_sighdlr(int sig, short event, void *arg)
149 {
150 	/*
151 	 * Normal signal handler rules don't apply because libevent
152 	 * decouples for us.
153 	 */
154 
155 	switch (sig) {
156 	case SIGHUP:
157 		log_info("%s: ignoring SIGHUP", __func__);
158 		break;
159 	case SIGUSR1:
160 		log_info("%s: ignoring SIGUSR1", __func__);
161 		break;
162 	case SIGTERM:
163 	case SIGINT:
164 		gotd_session_shutdown();
165 		/* NOTREACHED */
166 		break;
167 	default:
168 		fatalx("unexpected signal");
169 	}
170 }
171 
172 static const struct got_error *
173 recv_packfile_done(uint32_t *client_id, struct imsg *imsg)
174 {
175 	struct gotd_imsg_packfile_done idone;
176 	size_t datalen;
177 
178 	log_debug("packfile-done received");
179 
180 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
181 	if (datalen != sizeof(idone))
182 		return got_error(GOT_ERR_PRIVSEP_LEN);
183 	memcpy(&idone, imsg->data, sizeof(idone));
184 
185 	*client_id = idone.client_id;
186 	return NULL;
187 }
188 
189 static const struct got_error *
190 recv_packfile_install(uint32_t *client_id, struct imsg *imsg)
191 {
192 	struct gotd_imsg_packfile_install inst;
193 	size_t datalen;
194 
195 	log_debug("packfile-install received");
196 
197 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
198 	if (datalen != sizeof(inst))
199 		return got_error(GOT_ERR_PRIVSEP_LEN);
200 	memcpy(&inst, imsg->data, sizeof(inst));
201 
202 	*client_id = inst.client_id;
203 	return NULL;
204 }
205 
206 static const struct got_error *
207 recv_ref_updates_start(uint32_t *client_id, struct imsg *imsg)
208 {
209 	struct gotd_imsg_ref_updates_start istart;
210 	size_t datalen;
211 
212 	log_debug("ref-updates-start received");
213 
214 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
215 	if (datalen != sizeof(istart))
216 		return got_error(GOT_ERR_PRIVSEP_LEN);
217 	memcpy(&istart, imsg->data, sizeof(istart));
218 
219 	*client_id = istart.client_id;
220 	return NULL;
221 }
222 
223 static const struct got_error *
224 recv_ref_update(uint32_t *client_id, struct imsg *imsg)
225 {
226 	struct gotd_imsg_ref_update iref;
227 	size_t datalen;
228 
229 	log_debug("ref-update received");
230 
231 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
232 	if (datalen < sizeof(iref))
233 		return got_error(GOT_ERR_PRIVSEP_LEN);
234 	memcpy(&iref, imsg->data, sizeof(iref));
235 
236 	*client_id = iref.client_id;
237 	return NULL;
238 }
239 
240 static const struct got_error *
241 send_ref_update_ok(struct gotd_session_client *client,
242     struct gotd_imsg_ref_update *iref, const char *refname)
243 {
244 	struct gotd_imsg_ref_update_ok iok;
245 	struct gotd_imsgev *iev = &client->iev;
246 	struct ibuf *wbuf;
247 	size_t len;
248 
249 	memset(&iok, 0, sizeof(iok));
250 	iok.client_id = client->id;
251 	memcpy(iok.old_id, iref->old_id, SHA1_DIGEST_LENGTH);
252 	memcpy(iok.new_id, iref->new_id, SHA1_DIGEST_LENGTH);
253 	iok.name_len = strlen(refname);
254 
255 	len = sizeof(iok) + iok.name_len;
256 	wbuf = imsg_create(&iev->ibuf, GOTD_IMSG_REF_UPDATE_OK,
257 	    gotd_session.proc_id, gotd_session.pid, len);
258 	if (wbuf == NULL)
259 		return got_error_from_errno("imsg_create REF_UPDATE_OK");
260 
261 	if (imsg_add(wbuf, &iok, sizeof(iok)) == -1)
262 		return got_error_from_errno("imsg_add REF_UPDATE_OK");
263 	if (imsg_add(wbuf, refname, iok.name_len) == -1)
264 		return got_error_from_errno("imsg_add REF_UPDATE_OK");
265 
266 	wbuf->fd = -1;
267 	imsg_close(&iev->ibuf, wbuf);
268 	gotd_imsg_event_add(iev);
269 	return NULL;
270 }
271 
272 static void
273 send_refs_updated(struct gotd_session_client *client)
274 {
275 	if (gotd_imsg_compose_event(&client->iev, GOTD_IMSG_REFS_UPDATED,
276 	    gotd_session.proc_id, -1, NULL, 0) == -1)
277 		log_warn("imsg compose REFS_UPDATED");
278 }
279 
280 static const struct got_error *
281 send_ref_update_ng(struct gotd_session_client *client,
282     struct gotd_imsg_ref_update *iref, const char *refname,
283     const char *reason)
284 {
285 	const struct got_error *ng_err;
286 	struct gotd_imsg_ref_update_ng ing;
287 	struct gotd_imsgev *iev = &client->iev;
288 	struct ibuf *wbuf;
289 	size_t len;
290 
291 	memset(&ing, 0, sizeof(ing));
292 	ing.client_id = client->id;
293 	memcpy(ing.old_id, iref->old_id, SHA1_DIGEST_LENGTH);
294 	memcpy(ing.new_id, iref->new_id, SHA1_DIGEST_LENGTH);
295 	ing.name_len = strlen(refname);
296 
297 	ng_err = got_error_fmt(GOT_ERR_REF_BUSY, "%s", reason);
298 	ing.reason_len = strlen(ng_err->msg);
299 
300 	len = sizeof(ing) + ing.name_len + ing.reason_len;
301 	wbuf = imsg_create(&iev->ibuf, GOTD_IMSG_REF_UPDATE_NG,
302 	    gotd_session.proc_id, gotd_session.pid, len);
303 	if (wbuf == NULL)
304 		return got_error_from_errno("imsg_create REF_UPDATE_NG");
305 
306 	if (imsg_add(wbuf, &ing, sizeof(ing)) == -1)
307 		return got_error_from_errno("imsg_add REF_UPDATE_NG");
308 	if (imsg_add(wbuf, refname, ing.name_len) == -1)
309 		return got_error_from_errno("imsg_add REF_UPDATE_NG");
310 	if (imsg_add(wbuf, ng_err->msg, ing.reason_len) == -1)
311 		return got_error_from_errno("imsg_add REF_UPDATE_NG");
312 
313 	wbuf->fd = -1;
314 	imsg_close(&iev->ibuf, wbuf);
315 	gotd_imsg_event_add(iev);
316 	return NULL;
317 }
318 
319 static const struct got_error *
320 install_pack(struct gotd_session_client *client, const char *repo_path,
321     struct imsg *imsg)
322 {
323 	const struct got_error *err = NULL;
324 	struct gotd_imsg_packfile_install inst;
325 	char hex[SHA1_DIGEST_STRING_LENGTH];
326 	size_t datalen;
327 	char *packfile_path = NULL, *packidx_path = NULL;
328 
329 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
330 	if (datalen != sizeof(inst))
331 		return got_error(GOT_ERR_PRIVSEP_LEN);
332 	memcpy(&inst, imsg->data, sizeof(inst));
333 
334 	if (client->packfile_path == NULL)
335 		return got_error_msg(GOT_ERR_BAD_REQUEST,
336 		    "client has no pack file");
337 	if (client->packidx_path == NULL)
338 		return got_error_msg(GOT_ERR_BAD_REQUEST,
339 		    "client has no pack file index");
340 
341 	if (got_sha1_digest_to_str(inst.pack_sha1, hex, sizeof(hex)) == NULL)
342 		return got_error_msg(GOT_ERR_NO_SPACE,
343 		    "could not convert pack file SHA1 to hex");
344 
345 	if (asprintf(&packfile_path, "/%s/%s/pack-%s.pack",
346 	    repo_path, GOT_OBJECTS_PACK_DIR, hex) == -1) {
347 		err = got_error_from_errno("asprintf");
348 		goto done;
349 	}
350 
351 	if (asprintf(&packidx_path, "/%s/%s/pack-%s.idx",
352 	    repo_path, GOT_OBJECTS_PACK_DIR, hex) == -1) {
353 		err = got_error_from_errno("asprintf");
354 		goto done;
355 	}
356 
357 	if (rename(client->packfile_path, packfile_path) == -1) {
358 		err = got_error_from_errno3("rename", client->packfile_path,
359 		    packfile_path);
360 		goto done;
361 	}
362 
363 	free(client->packfile_path);
364 	client->packfile_path = NULL;
365 
366 	if (rename(client->packidx_path, packidx_path) == -1) {
367 		err = got_error_from_errno3("rename", client->packidx_path,
368 		    packidx_path);
369 		goto done;
370 	}
371 
372 	free(client->packidx_path);
373 	client->packidx_path = NULL;
374 done:
375 	free(packfile_path);
376 	free(packidx_path);
377 	return err;
378 }
379 
380 static const struct got_error *
381 begin_ref_updates(struct gotd_session_client *client, struct imsg *imsg)
382 {
383 	struct gotd_imsg_ref_updates_start istart;
384 	size_t datalen;
385 
386 	if (client->nref_updates != -1)
387 		return got_error(GOT_ERR_PRIVSEP_MSG);
388 
389 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
390 	if (datalen != sizeof(istart))
391 		return got_error(GOT_ERR_PRIVSEP_LEN);
392 	memcpy(&istart, imsg->data, sizeof(istart));
393 
394 	if (istart.nref_updates <= 0)
395 		return got_error(GOT_ERR_PRIVSEP_MSG);
396 
397 	client->nref_updates = istart.nref_updates;
398 	return NULL;
399 }
400 
401 static const struct got_error *
402 update_ref(int *shut, struct gotd_session_client *client,
403     const char *repo_path, struct imsg *imsg)
404 {
405 	const struct got_error *err = NULL;
406 	struct got_repository *repo = NULL;
407 	struct got_reference *ref = NULL;
408 	struct gotd_imsg_ref_update iref;
409 	struct got_object_id old_id, new_id;
410 	struct got_object_id *id = NULL;
411 	char *refname = NULL;
412 	size_t datalen;
413 	int locked = 0;
414 	char hex1[SHA1_DIGEST_STRING_LENGTH];
415 	char hex2[SHA1_DIGEST_STRING_LENGTH];
416 
417 	log_debug("update-ref from uid %d", client->euid);
418 
419 	if (client->nref_updates <= 0)
420 		return got_error(GOT_ERR_PRIVSEP_MSG);
421 
422 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
423 	if (datalen < sizeof(iref))
424 		return got_error(GOT_ERR_PRIVSEP_LEN);
425 	memcpy(&iref, imsg->data, sizeof(iref));
426 	if (datalen != sizeof(iref) + iref.name_len)
427 		return got_error(GOT_ERR_PRIVSEP_LEN);
428 	refname = strndup(imsg->data + sizeof(iref), iref.name_len);
429 	if (refname == NULL)
430 		return got_error_from_errno("strndup");
431 
432 	log_debug("updating ref %s for uid %d", refname, client->euid);
433 
434 	err = got_repo_open(&repo, repo_path, NULL, NULL);
435 	if (err)
436 		goto done;
437 
438 	memcpy(old_id.sha1, iref.old_id, SHA1_DIGEST_LENGTH);
439 	memcpy(new_id.sha1, iref.new_id, SHA1_DIGEST_LENGTH);
440 	err = got_repo_find_object_id(iref.delete_ref ? &old_id : &new_id,
441 	    repo);
442 	if (err)
443 		goto done;
444 
445 	if (iref.ref_is_new) {
446 		err = got_ref_open(&ref, repo, refname, 0);
447 		if (err) {
448 			if (err->code != GOT_ERR_NOT_REF)
449 				goto done;
450 			err = got_ref_alloc(&ref, refname, &new_id);
451 			if (err)
452 				goto done;
453 			err = got_ref_write(ref, repo); /* will lock/unlock */
454 			if (err)
455 				goto done;
456 		} else {
457 			err = got_ref_resolve(&id, repo, ref);
458 			if (err)
459 				goto done;
460 			got_object_id_hex(&new_id, hex1, sizeof(hex1));
461 			got_object_id_hex(id, hex2, sizeof(hex2));
462 			err = got_error_fmt(GOT_ERR_REF_BUSY,
463 			    "Addition %s: %s failed; %s: %s has been "
464 			    "created by someone else while transaction "
465 			    "was in progress",
466 			    got_ref_get_name(ref), hex1,
467 			    got_ref_get_name(ref), hex2);
468 			goto done;
469 		}
470 	} else if (iref.delete_ref) {
471 		err = got_ref_open(&ref, repo, refname, 1 /* lock */);
472 		if (err)
473 			goto done;
474 		locked = 1;
475 
476 		err = got_ref_resolve(&id, repo, ref);
477 		if (err)
478 			goto done;
479 
480 		if (got_object_id_cmp(id, &old_id) != 0) {
481 			got_object_id_hex(&old_id, hex1, sizeof(hex1));
482 			got_object_id_hex(id, hex2, sizeof(hex2));
483 			err = got_error_fmt(GOT_ERR_REF_BUSY,
484 			    "Deletion %s: %s failed; %s: %s has been "
485 			    "created by someone else while transaction "
486 			    "was in progress",
487 			    got_ref_get_name(ref), hex1,
488 			    got_ref_get_name(ref), hex2);
489 			goto done;
490 		}
491 
492 		err = got_ref_delete(ref, repo);
493 		if (err)
494 			goto done;
495 
496 		free(id);
497 		id = NULL;
498 	} else {
499 		err = got_ref_open(&ref, repo, refname, 1 /* lock */);
500 		if (err)
501 			goto done;
502 		locked = 1;
503 
504 		err = got_ref_resolve(&id, repo, ref);
505 		if (err)
506 			goto done;
507 
508 		if (got_object_id_cmp(id, &old_id) != 0) {
509 			got_object_id_hex(&old_id, hex1, sizeof(hex1));
510 			got_object_id_hex(id, hex2, sizeof(hex2));
511 			err = got_error_fmt(GOT_ERR_REF_BUSY,
512 			    "Update %s: %s failed; %s: %s has been "
513 			    "created by someone else while transaction "
514 			    "was in progress",
515 			    got_ref_get_name(ref), hex1,
516 			    got_ref_get_name(ref), hex2);
517 			goto done;
518 		}
519 
520 		if (got_object_id_cmp(&new_id, &old_id) != 0) {
521 			err = got_ref_change_ref(ref, &new_id);
522 			if (err)
523 				goto done;
524 
525 			err = got_ref_write(ref, repo);
526 			if (err)
527 				goto done;
528 		}
529 
530 		free(id);
531 		id = NULL;
532 	}
533 done:
534 	if (err) {
535 		if (err->code == GOT_ERR_LOCKFILE_TIMEOUT) {
536 			err = got_error_fmt(GOT_ERR_LOCKFILE_TIMEOUT,
537 			    "could not acquire exclusive file lock for %s",
538 			    refname);
539 		}
540 		send_ref_update_ng(client, &iref, refname, err->msg);
541 	} else
542 		send_ref_update_ok(client, &iref, refname);
543 
544 	if (client->nref_updates > 0) {
545 		client->nref_updates--;
546 		if (client->nref_updates == 0) {
547 			send_refs_updated(client);
548 			client->flush_disconnect = 1;
549 		}
550 
551 	}
552 	if (locked) {
553 		const struct got_error *unlock_err;
554 		unlock_err = got_ref_unlock(ref);
555 		if (unlock_err && err == NULL)
556 			err = unlock_err;
557 	}
558 	if (ref)
559 		got_ref_close(ref);
560 	if (repo)
561 		got_repo_close(repo);
562 	free(refname);
563 	free(id);
564 	return err;
565 }
566 
567 static void
568 session_dispatch_repo_child(int fd, short event, void *arg)
569 {
570 	struct gotd_imsgev *iev = arg;
571 	struct imsgbuf *ibuf = &iev->ibuf;
572 	struct gotd_session_client *client = &gotd_session_client;
573 	ssize_t n;
574 	int shut = 0;
575 	struct imsg imsg;
576 
577 	if (event & EV_READ) {
578 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
579 			fatal("imsg_read error");
580 		if (n == 0) {
581 			/* Connection closed. */
582 			shut = 1;
583 			goto done;
584 		}
585 	}
586 
587 	if (event & EV_WRITE) {
588 		n = msgbuf_write(&ibuf->w);
589 		if (n == -1 && errno != EAGAIN)
590 			fatal("msgbuf_write");
591 		if (n == 0) {
592 			/* Connection closed. */
593 			shut = 1;
594 			goto done;
595 		}
596 	}
597 
598 	for (;;) {
599 		const struct got_error *err = NULL;
600 		uint32_t client_id = 0;
601 		int do_disconnect = 0;
602 		int do_ref_updates = 0, do_ref_update = 0;
603 		int do_packfile_install = 0;
604 
605 		if ((n = imsg_get(ibuf, &imsg)) == -1)
606 			fatal("%s: imsg_get error", __func__);
607 		if (n == 0)	/* No more messages. */
608 			break;
609 
610 		switch (imsg.hdr.type) {
611 		case GOTD_IMSG_ERROR:
612 			do_disconnect = 1;
613 			err = gotd_imsg_recv_error(&client_id, &imsg);
614 			break;
615 		case GOTD_IMSG_PACKFILE_DONE:
616 			do_disconnect = 1;
617 			err = recv_packfile_done(&client_id, &imsg);
618 			break;
619 		case GOTD_IMSG_PACKFILE_INSTALL:
620 			err = recv_packfile_install(&client_id, &imsg);
621 			if (err == NULL)
622 				do_packfile_install = 1;
623 			break;
624 		case GOTD_IMSG_REF_UPDATES_START:
625 			err = recv_ref_updates_start(&client_id, &imsg);
626 			if (err == NULL)
627 				do_ref_updates = 1;
628 			break;
629 		case GOTD_IMSG_REF_UPDATE:
630 			err = recv_ref_update(&client_id, &imsg);
631 			if (err == NULL)
632 				do_ref_update = 1;
633 			break;
634 		default:
635 			log_debug("unexpected imsg %d", imsg.hdr.type);
636 			break;
637 		}
638 
639 		if (do_disconnect) {
640 			if (err)
641 				disconnect_on_error(client, err);
642 			else
643 				disconnect(client);
644 		} else {
645 			if (do_packfile_install)
646 				err = install_pack(client,
647 				    gotd_session.repo->path, &imsg);
648 			else if (do_ref_updates)
649 				err = begin_ref_updates(client, &imsg);
650 			else if (do_ref_update)
651 				err = update_ref(&shut, client,
652 				    gotd_session.repo->path, &imsg);
653 			if (err)
654 				log_warnx("uid %d: %s", client->euid, err->msg);
655 		}
656 		imsg_free(&imsg);
657 	}
658 done:
659 	if (!shut) {
660 		gotd_imsg_event_add(iev);
661 	} else {
662 		/* This pipe is dead. Remove its event handler */
663 		event_del(&iev->ev);
664 		event_loopexit(NULL);
665 	}
666 }
667 
668 static const struct got_error *
669 recv_capabilities(struct gotd_session_client *client, struct imsg *imsg)
670 {
671 	struct gotd_imsg_capabilities icapas;
672 	size_t datalen;
673 
674 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
675 	if (datalen != sizeof(icapas))
676 		return got_error(GOT_ERR_PRIVSEP_LEN);
677 	memcpy(&icapas, imsg->data, sizeof(icapas));
678 
679 	client->ncapa_alloc = icapas.ncapabilities;
680 	client->capabilities = calloc(client->ncapa_alloc,
681 	    sizeof(*client->capabilities));
682 	if (client->capabilities == NULL) {
683 		client->ncapa_alloc = 0;
684 		return got_error_from_errno("calloc");
685 	}
686 
687 	log_debug("expecting %zu capabilities from uid %d",
688 	    client->ncapa_alloc, client->euid);
689 	return NULL;
690 }
691 
692 static const struct got_error *
693 recv_capability(struct gotd_session_client *client, struct imsg *imsg)
694 {
695 	struct gotd_imsg_capability icapa;
696 	struct gotd_client_capability *capa;
697 	size_t datalen;
698 	char *key, *value = NULL;
699 
700 	if (client->capabilities == NULL ||
701 	    client->ncapabilities >= client->ncapa_alloc) {
702 		return got_error_msg(GOT_ERR_BAD_REQUEST,
703 		    "unexpected capability received");
704 	}
705 
706 	memset(&icapa, 0, sizeof(icapa));
707 
708 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
709 	if (datalen < sizeof(icapa))
710 		return got_error(GOT_ERR_PRIVSEP_LEN);
711 	memcpy(&icapa, imsg->data, sizeof(icapa));
712 
713 	if (datalen != sizeof(icapa) + icapa.key_len + icapa.value_len)
714 		return got_error(GOT_ERR_PRIVSEP_LEN);
715 
716 	key = strndup(imsg->data + sizeof(icapa), icapa.key_len);
717 	if (key == NULL)
718 		return got_error_from_errno("strndup");
719 	if (icapa.value_len > 0) {
720 		value = strndup(imsg->data + sizeof(icapa) + icapa.key_len,
721 		    icapa.value_len);
722 		if (value == NULL) {
723 			free(key);
724 			return got_error_from_errno("strndup");
725 		}
726 	}
727 
728 	capa = &client->capabilities[client->ncapabilities++];
729 	capa->key = key;
730 	capa->value = value;
731 
732 	if (value)
733 		log_debug("uid %d: capability %s=%s", client->euid, key, value);
734 	else
735 		log_debug("uid %d: capability %s", client->euid, key);
736 
737 	return NULL;
738 }
739 
740 static const struct got_error *
741 ensure_client_is_reading(struct gotd_session_client *client)
742 {
743 	if (client->is_writing) {
744 		return got_error_fmt(GOT_ERR_BAD_PACKET,
745 		    "uid %d made a read-request but is not reading from "
746 		    "a repository", client->euid);
747 	}
748 
749 	return NULL;
750 }
751 
752 static const struct got_error *
753 ensure_client_is_writing(struct gotd_session_client *client)
754 {
755 	if (!client->is_writing) {
756 		return got_error_fmt(GOT_ERR_BAD_PACKET,
757 		    "uid %d made a write-request but is not writing to "
758 		    "a repository", client->euid);
759 	}
760 
761 	return NULL;
762 }
763 
764 static const struct got_error *
765 forward_want(struct gotd_session_client *client, struct imsg *imsg)
766 {
767 	struct gotd_imsg_want ireq;
768 	struct gotd_imsg_want iwant;
769 	size_t datalen;
770 
771 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
772 	if (datalen != sizeof(ireq))
773 		return got_error(GOT_ERR_PRIVSEP_LEN);
774 
775 	memcpy(&ireq, imsg->data, datalen);
776 
777 	memset(&iwant, 0, sizeof(iwant));
778 	memcpy(iwant.object_id, ireq.object_id, SHA1_DIGEST_LENGTH);
779 	iwant.client_id = client->id;
780 
781 	if (gotd_imsg_compose_event(&client->repo_child_iev, GOTD_IMSG_WANT,
782 	    gotd_session.proc_id, -1, &iwant, sizeof(iwant)) == -1)
783 		return got_error_from_errno("imsg compose WANT");
784 
785 	return NULL;
786 }
787 
788 static const struct got_error *
789 forward_ref_update(struct gotd_session_client *client, struct imsg *imsg)
790 {
791 	const struct got_error *err = NULL;
792 	struct gotd_imsg_ref_update ireq;
793 	struct gotd_imsg_ref_update *iref = NULL;
794 	size_t datalen;
795 
796 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
797 	if (datalen < sizeof(ireq))
798 		return got_error(GOT_ERR_PRIVSEP_LEN);
799 	memcpy(&ireq, imsg->data, sizeof(ireq));
800 	if (datalen != sizeof(ireq) + ireq.name_len)
801 		return got_error(GOT_ERR_PRIVSEP_LEN);
802 
803 	iref = malloc(datalen);
804 	if (iref == NULL)
805 		return got_error_from_errno("malloc");
806 	memcpy(iref, imsg->data, datalen);
807 
808 	iref->client_id = client->id;
809 	if (gotd_imsg_compose_event(&client->repo_child_iev,
810 	    GOTD_IMSG_REF_UPDATE, gotd_session.proc_id, -1,
811 	    iref, datalen) == -1)
812 		err = got_error_from_errno("imsg compose REF_UPDATE");
813 	free(iref);
814 	return err;
815 }
816 
817 static const struct got_error *
818 forward_have(struct gotd_session_client *client, struct imsg *imsg)
819 {
820 	struct gotd_imsg_have ireq;
821 	struct gotd_imsg_have ihave;
822 	size_t datalen;
823 
824 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
825 	if (datalen != sizeof(ireq))
826 		return got_error(GOT_ERR_PRIVSEP_LEN);
827 
828 	memcpy(&ireq, imsg->data, datalen);
829 
830 	memset(&ihave, 0, sizeof(ihave));
831 	memcpy(ihave.object_id, ireq.object_id, SHA1_DIGEST_LENGTH);
832 	ihave.client_id = client->id;
833 
834 	if (gotd_imsg_compose_event(&client->repo_child_iev, GOTD_IMSG_HAVE,
835 	    gotd_session.proc_id, -1, &ihave, sizeof(ihave)) == -1)
836 		return got_error_from_errno("imsg compose HAVE");
837 
838 	return NULL;
839 }
840 
841 static int
842 client_has_capability(struct gotd_session_client *client, const char *capastr)
843 {
844 	struct gotd_client_capability *capa;
845 	size_t i;
846 
847 	if (client->ncapabilities == 0)
848 		return 0;
849 
850 	for (i = 0; i < client->ncapabilities; i++) {
851 		capa = &client->capabilities[i];
852 		if (strcmp(capa->key, capastr) == 0)
853 			return 1;
854 	}
855 
856 	return 0;
857 }
858 
859 static const struct got_error *
860 recv_packfile(struct gotd_session_client *client)
861 {
862 	const struct got_error *err = NULL;
863 	struct gotd_imsg_recv_packfile ipack;
864 	struct gotd_imsg_packfile_pipe ipipe;
865 	struct gotd_imsg_packidx_file ifile;
866 	char *basepath = NULL, *pack_path = NULL, *idx_path = NULL;
867 	int packfd = -1, idxfd = -1;
868 	int pipe[2] = { -1, -1 };
869 
870 	if (client->packfile_path) {
871 		return got_error_fmt(GOT_ERR_PRIVSEP_MSG,
872 		    "uid %d already has a pack file", client->euid);
873 	}
874 
875 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pipe) == -1)
876 		return got_error_from_errno("socketpair");
877 
878 	memset(&ipipe, 0, sizeof(ipipe));
879 	ipipe.client_id = client->id;
880 
881 	/* Send pack pipe end 0 to repo child process. */
882 	if (gotd_imsg_compose_event(&client->repo_child_iev,
883 	    GOTD_IMSG_PACKFILE_PIPE, gotd_session.proc_id, pipe[0],
884 	        &ipipe, sizeof(ipipe)) == -1) {
885 		err = got_error_from_errno("imsg compose PACKFILE_PIPE");
886 		pipe[0] = -1;
887 		goto done;
888 	}
889 	pipe[0] = -1;
890 
891 	/* Send pack pipe end 1 to gotsh(1) (expects just an fd, no data). */
892 	if (gotd_imsg_compose_event(&client->iev,
893 	    GOTD_IMSG_PACKFILE_PIPE, gotd_session.proc_id, pipe[1],
894 	    NULL, 0) == -1)
895 		err = got_error_from_errno("imsg compose PACKFILE_PIPE");
896 	pipe[1] = -1;
897 
898 	if (asprintf(&basepath, "%s/%s/receiving-from-uid-%d.pack",
899 	    got_repo_get_path(gotd_session.repo), GOT_OBJECTS_PACK_DIR,
900 	    client->euid) == -1) {
901 		err = got_error_from_errno("asprintf");
902 		goto done;
903 	}
904 
905 	err = got_opentemp_named_fd(&pack_path, &packfd, basepath, "");
906 	if (err)
907 		goto done;
908 	if (fchmod(packfd, GOT_DEFAULT_PACK_MODE) == -1) {
909 		err = got_error_from_errno2("fchmod", pack_path);
910 		goto done;
911 	}
912 
913 	free(basepath);
914 	if (asprintf(&basepath, "%s/%s/receiving-from-uid-%d.idx",
915 	    got_repo_get_path(gotd_session.repo), GOT_OBJECTS_PACK_DIR,
916 	    client->euid) == -1) {
917 		err = got_error_from_errno("asprintf");
918 		basepath = NULL;
919 		goto done;
920 	}
921 	err = got_opentemp_named_fd(&idx_path, &idxfd, basepath, "");
922 	if (err)
923 		goto done;
924 	if (fchmod(idxfd, GOT_DEFAULT_PACK_MODE) == -1) {
925 		err = got_error_from_errno2("fchmod", idx_path);
926 		goto done;
927 	}
928 
929 	memset(&ifile, 0, sizeof(ifile));
930 	ifile.client_id = client->id;
931 	if (gotd_imsg_compose_event(&client->repo_child_iev,
932 	    GOTD_IMSG_PACKIDX_FILE, gotd_session.proc_id,
933 	    idxfd, &ifile, sizeof(ifile)) == -1) {
934 		err = got_error_from_errno("imsg compose PACKIDX_FILE");
935 		idxfd = -1;
936 		goto done;
937 	}
938 	idxfd = -1;
939 
940 	memset(&ipack, 0, sizeof(ipack));
941 	ipack.client_id = client->id;
942 	if (client_has_capability(client, GOT_CAPA_REPORT_STATUS))
943 		ipack.report_status = 1;
944 
945 	if (gotd_imsg_compose_event(&client->repo_child_iev,
946 	    GOTD_IMSG_RECV_PACKFILE, gotd_session.proc_id, packfd,
947 	    &ipack, sizeof(ipack)) == -1) {
948 		err = got_error_from_errno("imsg compose RECV_PACKFILE");
949 		packfd = -1;
950 		goto done;
951 	}
952 	packfd = -1;
953 
954 done:
955 	free(basepath);
956 	if (pipe[0] != -1 && close(pipe[0]) == -1 && err == NULL)
957 		err = got_error_from_errno("close");
958 	if (pipe[1] != -1 && close(pipe[1]) == -1 && err == NULL)
959 		err = got_error_from_errno("close");
960 	if (packfd != -1 && close(packfd) == -1 && err == NULL)
961 		err = got_error_from_errno("close");
962 	if (idxfd != -1 && close(idxfd) == -1 && err == NULL)
963 		err = got_error_from_errno("close");
964 	if (err) {
965 		free(pack_path);
966 		free(idx_path);
967 	} else {
968 		client->packfile_path = pack_path;
969 		client->packidx_path = idx_path;
970 	}
971 	return err;
972 }
973 
974 static const struct got_error *
975 send_packfile(struct gotd_session_client *client)
976 {
977 	const struct got_error *err = NULL;
978 	struct gotd_imsg_send_packfile ipack;
979 	struct gotd_imsg_packfile_pipe ipipe;
980 	int pipe[2];
981 
982 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pipe) == -1)
983 		return got_error_from_errno("socketpair");
984 
985 	memset(&ipack, 0, sizeof(ipack));
986 	memset(&ipipe, 0, sizeof(ipipe));
987 
988 	ipack.client_id = client->id;
989 	if (client_has_capability(client, GOT_CAPA_SIDE_BAND_64K))
990 		ipack.report_progress = 1;
991 
992 	client->delta_cache_fd = got_opentempfd();
993 	if (client->delta_cache_fd == -1)
994 		return got_error_from_errno("got_opentempfd");
995 
996 	if (gotd_imsg_compose_event(&client->repo_child_iev,
997 	    GOTD_IMSG_SEND_PACKFILE, PROC_GOTD, client->delta_cache_fd,
998 	    &ipack, sizeof(ipack)) == -1) {
999 		err = got_error_from_errno("imsg compose SEND_PACKFILE");
1000 		close(pipe[0]);
1001 		close(pipe[1]);
1002 		return err;
1003 	}
1004 
1005 	ipipe.client_id = client->id;
1006 
1007 	/* Send pack pipe end 0 to repo child process. */
1008 	if (gotd_imsg_compose_event(&client->repo_child_iev,
1009 	    GOTD_IMSG_PACKFILE_PIPE, PROC_GOTD,
1010 	    pipe[0], &ipipe, sizeof(ipipe)) == -1) {
1011 		err = got_error_from_errno("imsg compose PACKFILE_PIPE");
1012 		close(pipe[1]);
1013 		return err;
1014 	}
1015 
1016 	/* Send pack pipe end 1 to gotsh(1) (expects just an fd, no data). */
1017 	if (gotd_imsg_compose_event(&client->iev,
1018 	    GOTD_IMSG_PACKFILE_PIPE, PROC_GOTD, pipe[1], NULL, 0) == -1)
1019 		err = got_error_from_errno("imsg compose PACKFILE_PIPE");
1020 
1021 	return err;
1022 }
1023 
1024 static void
1025 session_dispatch_client(int fd, short events, void *arg)
1026 {
1027 	struct gotd_imsgev *iev = arg;
1028 	struct imsgbuf *ibuf = &iev->ibuf;
1029 	struct gotd_session_client *client = &gotd_session_client;
1030 	const struct got_error *err = NULL;
1031 	struct imsg imsg;
1032 	ssize_t n;
1033 
1034 	if (events & EV_WRITE) {
1035 		while (ibuf->w.queued) {
1036 			n = msgbuf_write(&ibuf->w);
1037 			if (n == -1 && errno == EPIPE) {
1038 				/*
1039 				 * The client has closed its socket.
1040 				 * This can happen when Git clients are
1041 				 * done sending pack file data.
1042 				 */
1043 				msgbuf_clear(&ibuf->w);
1044 				continue;
1045 			} else if (n == -1 && errno != EAGAIN) {
1046 				err = got_error_from_errno("imsg_flush");
1047 				disconnect_on_error(client, err);
1048 				return;
1049 			}
1050 			if (n == 0) {
1051 				/* Connection closed. */
1052 				err = got_error(GOT_ERR_EOF);
1053 				disconnect_on_error(client, err);
1054 				return;
1055 			}
1056 		}
1057 
1058 		if (client->flush_disconnect) {
1059 			disconnect(client);
1060 			return;
1061 		}
1062 	}
1063 
1064 	if ((events & EV_READ) == 0)
1065 		return;
1066 
1067 	memset(&imsg, 0, sizeof(imsg));
1068 
1069 	while (err == NULL) {
1070 		err = gotd_imsg_recv(&imsg, ibuf, 0);
1071 		if (err) {
1072 			if (err->code == GOT_ERR_PRIVSEP_READ)
1073 				err = NULL;
1074 			else if (err->code == GOT_ERR_EOF &&
1075 			    client->state == GOTD_STATE_EXPECT_CAPABILITIES) {
1076 				/*
1077 				 * The client has closed its socket before
1078 				 * sending its capability announcement.
1079 				 * This can happen when Git clients have
1080 				 * no ref-updates to send.
1081 				 */
1082 				disconnect_on_error(client, err);
1083 				return;
1084 			}
1085 			break;
1086 		}
1087 
1088 		evtimer_del(&client->tmo);
1089 
1090 		switch (imsg.hdr.type) {
1091 		case GOTD_IMSG_CAPABILITIES:
1092 			if (client->state != GOTD_STATE_EXPECT_CAPABILITIES) {
1093 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1094 				    "unexpected capabilities received");
1095 				break;
1096 			}
1097 			log_debug("receiving capabilities from uid %d",
1098 			    client->euid);
1099 			err = recv_capabilities(client, &imsg);
1100 			break;
1101 		case GOTD_IMSG_CAPABILITY:
1102 			if (client->state != GOTD_STATE_EXPECT_CAPABILITIES) {
1103 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1104 				    "unexpected capability received");
1105 				break;
1106 			}
1107 			err = recv_capability(client, &imsg);
1108 			if (err || client->ncapabilities < client->ncapa_alloc)
1109 				break;
1110 			if (!client->is_writing) {
1111 				client->state = GOTD_STATE_EXPECT_WANT;
1112 				client->accept_flush_pkt = 1;
1113 				log_debug("uid %d: expecting want-lines",
1114 				    client->euid);
1115 			} else if (client->is_writing) {
1116 				client->state = GOTD_STATE_EXPECT_REF_UPDATE;
1117 				client->accept_flush_pkt = 1;
1118 				log_debug("uid %d: expecting ref-update-lines",
1119 				    client->euid);
1120 			} else
1121 				fatalx("client %d is both reading and writing",
1122 				    client->euid);
1123 			break;
1124 		case GOTD_IMSG_WANT:
1125 			if (client->state != GOTD_STATE_EXPECT_WANT) {
1126 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1127 				    "unexpected want-line received");
1128 				break;
1129 			}
1130 			log_debug("received want-line from uid %d",
1131 			    client->euid);
1132 			err = ensure_client_is_reading(client);
1133 			if (err)
1134 				break;
1135 			client->accept_flush_pkt = 1;
1136 			err = forward_want(client, &imsg);
1137 			break;
1138 		case GOTD_IMSG_REF_UPDATE:
1139 			if (client->state != GOTD_STATE_EXPECT_REF_UPDATE &&
1140 			    client->state !=
1141 			    GOTD_STATE_EXPECT_MORE_REF_UPDATES) {
1142 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1143 				    "unexpected ref-update-line received");
1144 				break;
1145 			}
1146 			log_debug("received ref-update-line from uid %d",
1147 			    client->euid);
1148 			err = ensure_client_is_writing(client);
1149 			if (err)
1150 				break;
1151 			err = forward_ref_update(client, &imsg);
1152 			if (err)
1153 				break;
1154 			client->state = GOTD_STATE_EXPECT_MORE_REF_UPDATES;
1155 			client->accept_flush_pkt = 1;
1156 			break;
1157 		case GOTD_IMSG_HAVE:
1158 			if (client->state != GOTD_STATE_EXPECT_HAVE) {
1159 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1160 				    "unexpected have-line received");
1161 				break;
1162 			}
1163 			log_debug("received have-line from uid %d",
1164 			    client->euid);
1165 			err = ensure_client_is_reading(client);
1166 			if (err)
1167 				break;
1168 			err = forward_have(client, &imsg);
1169 			if (err)
1170 				break;
1171 			client->accept_flush_pkt = 1;
1172 			break;
1173 		case GOTD_IMSG_FLUSH:
1174 			if (client->state == GOTD_STATE_EXPECT_WANT ||
1175 			    client->state == GOTD_STATE_EXPECT_HAVE) {
1176 				err = ensure_client_is_reading(client);
1177 				if (err)
1178 					break;
1179 			} else if (client->state ==
1180 			    GOTD_STATE_EXPECT_MORE_REF_UPDATES) {
1181 				err = ensure_client_is_writing(client);
1182 				if (err)
1183 					break;
1184 			} else if (client->state != GOTD_STATE_EXPECT_DONE) {
1185 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1186 				    "unexpected flush-pkt received");
1187 				break;
1188 			}
1189 			if (!client->accept_flush_pkt) {
1190 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1191 				    "unexpected flush-pkt received");
1192 				break;
1193 			}
1194 
1195 			/*
1196 			 * Accept just one flush packet at a time.
1197 			 * Future client state transitions will set this flag
1198 			 * again if another flush packet is expected.
1199 			 */
1200 			client->accept_flush_pkt = 0;
1201 
1202 			log_debug("received flush-pkt from uid %d",
1203 			    client->euid);
1204 			if (client->state == GOTD_STATE_EXPECT_WANT) {
1205 				client->state = GOTD_STATE_EXPECT_HAVE;
1206 				log_debug("uid %d: expecting have-lines",
1207 				    client->euid);
1208 			} else if (client->state == GOTD_STATE_EXPECT_HAVE) {
1209 				client->state = GOTD_STATE_EXPECT_DONE;
1210 				client->accept_flush_pkt = 1;
1211 				log_debug("uid %d: expecting 'done'",
1212 				    client->euid);
1213 			} else if (client->state ==
1214 			    GOTD_STATE_EXPECT_MORE_REF_UPDATES) {
1215 				client->state = GOTD_STATE_EXPECT_PACKFILE;
1216 				log_debug("uid %d: expecting packfile",
1217 				    client->euid);
1218 				err = recv_packfile(client);
1219 			} else if (client->state != GOTD_STATE_EXPECT_DONE) {
1220 				/* should not happen, see above */
1221 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1222 				    "unexpected client state");
1223 				break;
1224 			}
1225 			break;
1226 		case GOTD_IMSG_DONE:
1227 			if (client->state != GOTD_STATE_EXPECT_HAVE &&
1228 			    client->state != GOTD_STATE_EXPECT_DONE) {
1229 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1230 				    "unexpected flush-pkt received");
1231 				break;
1232 			}
1233 			log_debug("received 'done' from uid %d", client->euid);
1234 			err = ensure_client_is_reading(client);
1235 			if (err)
1236 				break;
1237 			client->state = GOTD_STATE_DONE;
1238 			client->accept_flush_pkt = 1;
1239 			err = send_packfile(client);
1240 			break;
1241 		default:
1242 			log_debug("unexpected imsg %d", imsg.hdr.type);
1243 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1244 			break;
1245 		}
1246 
1247 		imsg_free(&imsg);
1248 	}
1249 
1250 	if (err) {
1251 		if (err->code != GOT_ERR_EOF ||
1252 		    client->state != GOTD_STATE_EXPECT_PACKFILE)
1253 			disconnect_on_error(client, err);
1254 	} else {
1255 		gotd_imsg_event_add(iev);
1256 		evtimer_add(&client->tmo, &gotd_session.request_timeout);
1257 	}
1258 }
1259 
1260 static const struct got_error *
1261 list_refs_request(void)
1262 {
1263 	static const struct got_error *err;
1264 	struct gotd_session_client *client = &gotd_session_client;
1265 	struct gotd_imsgev *iev = &client->repo_child_iev;
1266 	struct gotd_imsg_list_refs_internal ilref;
1267 	int fd;
1268 
1269 	if (client->state != GOTD_STATE_EXPECT_LIST_REFS)
1270 		return got_error(GOT_ERR_PRIVSEP_MSG);
1271 
1272 	memset(&ilref, 0, sizeof(ilref));
1273 	ilref.client_id = client->id;
1274 
1275 	fd = dup(client->fd);
1276 	if (fd == -1)
1277 		return got_error_from_errno("dup");
1278 
1279 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_LIST_REFS_INTERNAL,
1280 	    gotd_session.proc_id, fd, &ilref, sizeof(ilref)) == -1) {
1281 		err = got_error_from_errno("imsg compose LIST_REFS_INTERNAL");
1282 		close(fd);
1283 		return err;
1284 	}
1285 
1286 	client->state = GOTD_STATE_EXPECT_CAPABILITIES;
1287 	log_debug("uid %d: expecting capabilities", client->euid);
1288 	return NULL;
1289 }
1290 
1291 static const struct got_error *
1292 recv_connect(struct imsg *imsg)
1293 {
1294 	struct gotd_session_client *client = &gotd_session_client;
1295 	struct gotd_imsg_connect iconnect;
1296 	size_t datalen;
1297 
1298 	if (client->state != GOTD_STATE_EXPECT_LIST_REFS)
1299 		return got_error(GOT_ERR_PRIVSEP_MSG);
1300 
1301 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1302 	if (datalen != sizeof(iconnect))
1303 		return got_error(GOT_ERR_PRIVSEP_LEN);
1304 	memcpy(&iconnect, imsg->data, sizeof(iconnect));
1305 
1306 	if (imsg->fd == -1)
1307 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
1308 
1309 	client->fd = imsg->fd;
1310 	client->euid = iconnect.euid;
1311 	client->egid = iconnect.egid;
1312 
1313 	imsg_init(&client->iev.ibuf, client->fd);
1314 	client->iev.handler = session_dispatch_client;
1315 	client->iev.events = EV_READ;
1316 	client->iev.handler_arg = NULL;
1317 	event_set(&client->iev.ev, client->iev.ibuf.fd, EV_READ,
1318 	    session_dispatch_client, &client->iev);
1319 	gotd_imsg_event_add(&client->iev);
1320 	evtimer_set(&client->tmo, gotd_request_timeout, client);
1321 
1322 	return NULL;
1323 }
1324 
1325 static const struct got_error *
1326 recv_repo_child(struct imsg *imsg)
1327 {
1328 	struct gotd_imsg_connect_repo_child ichild;
1329 	struct gotd_session_client *client = &gotd_session_client;
1330 	size_t datalen;
1331 
1332 	if (client->state != GOTD_STATE_EXPECT_LIST_REFS)
1333 		return got_error(GOT_ERR_PRIVSEP_MSG);
1334 
1335 	/* We should already have received a pipe to the listener. */
1336 	if (client->fd == -1)
1337 		return got_error(GOT_ERR_PRIVSEP_MSG);
1338 
1339 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1340 	if (datalen != sizeof(ichild))
1341 		return got_error(GOT_ERR_PRIVSEP_LEN);
1342 
1343 	memcpy(&ichild, imsg->data, sizeof(ichild));
1344 
1345 	client->id = ichild.client_id;
1346 	if (ichild.proc_id == PROC_REPO_WRITE)
1347 		client->is_writing = 1;
1348 	else if (ichild.proc_id == PROC_REPO_READ)
1349 		client->is_writing = 0;
1350 	else
1351 		return got_error_msg(GOT_ERR_PRIVSEP_MSG,
1352 		    "bad child process type");
1353 
1354 	if (imsg->fd == -1)
1355 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
1356 
1357 	imsg_init(&client->repo_child_iev.ibuf, imsg->fd);
1358 	client->repo_child_iev.handler = session_dispatch_repo_child;
1359 	client->repo_child_iev.events = EV_READ;
1360 	client->repo_child_iev.handler_arg = NULL;
1361 	event_set(&client->repo_child_iev.ev, client->repo_child_iev.ibuf.fd,
1362 	    EV_READ, session_dispatch_repo_child, &client->repo_child_iev);
1363 	gotd_imsg_event_add(&client->repo_child_iev);
1364 
1365 	/* The "recvfd" pledge promise is no longer needed. */
1366 	if (pledge("stdio rpath wpath cpath sendfd fattr flock", NULL) == -1)
1367 		fatal("pledge");
1368 
1369 	return NULL;
1370 }
1371 
1372 static void
1373 session_dispatch(int fd, short event, void *arg)
1374 {
1375 	struct gotd_imsgev *iev = arg;
1376 	struct imsgbuf *ibuf = &iev->ibuf;
1377 	struct gotd_session_client *client = &gotd_session_client;
1378 	ssize_t n;
1379 	int shut = 0;
1380 	struct imsg imsg;
1381 
1382 	if (event & EV_READ) {
1383 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1384 			fatal("imsg_read error");
1385 		if (n == 0) {
1386 			/* Connection closed. */
1387 			shut = 1;
1388 			goto done;
1389 		}
1390 	}
1391 
1392 	if (event & EV_WRITE) {
1393 		n = msgbuf_write(&ibuf->w);
1394 		if (n == -1 && errno != EAGAIN)
1395 			fatal("msgbuf_write");
1396 		if (n == 0) {
1397 			/* Connection closed. */
1398 			shut = 1;
1399 			goto done;
1400 		}
1401 	}
1402 
1403 	for (;;) {
1404 		const struct got_error *err = NULL;
1405 		uint32_t client_id = 0;
1406 		int do_disconnect = 0, do_list_refs = 0;
1407 
1408 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1409 			fatal("%s: imsg_get error", __func__);
1410 		if (n == 0)	/* No more messages. */
1411 			break;
1412 
1413 		switch (imsg.hdr.type) {
1414 		case GOTD_IMSG_ERROR:
1415 			do_disconnect = 1;
1416 			err = gotd_imsg_recv_error(&client_id, &imsg);
1417 			break;
1418 		case GOTD_IMSG_CONNECT:
1419 			err = recv_connect(&imsg);
1420 			break;
1421 		case GOTD_IMSG_DISCONNECT:
1422 			do_disconnect = 1;
1423 			break;
1424 		case GOTD_IMSG_CONNECT_REPO_CHILD:
1425 			err = recv_repo_child(&imsg);
1426 			if (err)
1427 				break;
1428 			do_list_refs = 1;
1429 			break;
1430 		default:
1431 			log_debug("unexpected imsg %d", imsg.hdr.type);
1432 			break;
1433 		}
1434 		imsg_free(&imsg);
1435 
1436 		if (do_disconnect) {
1437 			if (err)
1438 				disconnect_on_error(client, err);
1439 			else
1440 				disconnect(client);
1441 		} else if (do_list_refs)
1442 			err = list_refs_request();
1443 
1444 		if (err)
1445 			log_warnx("uid %d: %s", client->euid, err->msg);
1446 	}
1447 done:
1448 	if (!shut) {
1449 		gotd_imsg_event_add(iev);
1450 	} else {
1451 		/* This pipe is dead. Remove its event handler */
1452 		event_del(&iev->ev);
1453 		event_loopexit(NULL);
1454 	}
1455 }
1456 
1457 void
1458 session_main(const char *title, const char *repo_path,
1459     int *pack_fds, int *temp_fds, struct timeval *request_timeout,
1460     enum gotd_procid proc_id)
1461 {
1462 	const struct got_error *err = NULL;
1463 	struct event evsigint, evsigterm, evsighup, evsigusr1;
1464 
1465 	gotd_session.title = title;
1466 	gotd_session.pid = getpid();
1467 	gotd_session.pack_fds = pack_fds;
1468 	gotd_session.temp_fds = temp_fds;
1469 	memcpy(&gotd_session.request_timeout, request_timeout,
1470 	    sizeof(gotd_session.request_timeout));
1471 	gotd_session.proc_id = proc_id;
1472 
1473 	err = got_repo_open(&gotd_session.repo, repo_path, NULL, pack_fds);
1474 	if (err)
1475 		goto done;
1476 	if (!got_repo_is_bare(gotd_session.repo)) {
1477 		err = got_error_msg(GOT_ERR_NOT_GIT_REPO,
1478 		    "bare git repository required");
1479 		goto done;
1480 	}
1481 
1482 	got_repo_temp_fds_set(gotd_session.repo, temp_fds);
1483 
1484 	signal_set(&evsigint, SIGINT, gotd_session_sighdlr, NULL);
1485 	signal_set(&evsigterm, SIGTERM, gotd_session_sighdlr, NULL);
1486 	signal_set(&evsighup, SIGHUP, gotd_session_sighdlr, NULL);
1487 	signal_set(&evsigusr1, SIGUSR1, gotd_session_sighdlr, NULL);
1488 	signal(SIGPIPE, SIG_IGN);
1489 
1490 	signal_add(&evsigint, NULL);
1491 	signal_add(&evsigterm, NULL);
1492 	signal_add(&evsighup, NULL);
1493 	signal_add(&evsigusr1, NULL);
1494 
1495 	gotd_session_client.state = GOTD_STATE_EXPECT_LIST_REFS;
1496 	gotd_session_client.fd = -1;
1497 	gotd_session_client.nref_updates = -1;
1498 	gotd_session_client.delta_cache_fd = -1;
1499 	gotd_session_client.accept_flush_pkt = 1;
1500 
1501 	imsg_init(&gotd_session.parent_iev.ibuf, GOTD_FILENO_MSG_PIPE);
1502 	gotd_session.parent_iev.handler = session_dispatch;
1503 	gotd_session.parent_iev.events = EV_READ;
1504 	gotd_session.parent_iev.handler_arg = NULL;
1505 	event_set(&gotd_session.parent_iev.ev, gotd_session.parent_iev.ibuf.fd,
1506 	    EV_READ, session_dispatch, &gotd_session.parent_iev);
1507 	if (gotd_imsg_compose_event(&gotd_session.parent_iev,
1508 	    GOTD_IMSG_CLIENT_SESSION_READY, gotd_session.proc_id,
1509 	    -1, NULL, 0) == -1) {
1510 		err = got_error_from_errno("imsg compose CLIENT_SESSION_READY");
1511 		goto done;
1512 	}
1513 
1514 	event_dispatch();
1515 done:
1516 	if (err)
1517 		log_warnx("%s: %s", title, err->msg);
1518 	gotd_session_shutdown();
1519 }
1520 
1521 void
1522 gotd_session_shutdown(void)
1523 {
1524 	log_debug("shutting down");
1525 	if (gotd_session.repo)
1526 		got_repo_close(gotd_session.repo);
1527 	got_repo_pack_fds_close(gotd_session.pack_fds);
1528 	got_repo_temp_fds_close(gotd_session.temp_fds);
1529 	exit(0);
1530 }