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 "got_compat.h"
18 
19 #include <sys/types.h>
20 #include <sys/queue.h>
21 #include <sys/socket.h>
22 #include <sys/stat.h>
23 #include <sys/uio.h>
24 
25 #include <errno.h>
26 #include <event.h>
27 #include <limits.h>
28 #include <signal.h>
29 #include <stdint.h>
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include <imsg.h>
34 #include <unistd.h>
35 
36 #include "got_compat.h"
37 
38 #include "got_error.h"
39 #include "got_repository.h"
40 #include "got_object.h"
41 #include "got_path.h"
42 #include "got_reference.h"
43 #include "got_opentemp.h"
44 
45 #include "got_lib_hash.h"
46 #include "got_lib_delta.h"
47 #include "got_lib_object.h"
48 #include "got_lib_object_cache.h"
49 #include "got_lib_pack.h"
50 #include "got_lib_repository.h"
51 #include "got_lib_gitproto.h"
52 
53 #include "gotd.h"
54 #include "log.h"
55 #include "session.h"
56 
57 
58 static struct gotd_session {
59 	pid_t pid;
60 	const char *title;
61 	struct got_repository *repo;
62 	int *pack_fds;
63 	int *temp_fds;
64 	struct gotd_imsgev parent_iev;
65 	struct timeval request_timeout;
66 	enum gotd_procid proc_id;
67 } gotd_session;
68 
69 static struct gotd_session_client {
70 	enum gotd_session_state		 state;
71 	int				 is_writing;
72 	struct gotd_client_capability	*capabilities;
73 	size_t				 ncapa_alloc;
74 	size_t				 ncapabilities;
75 	uint32_t			 id;
76 	int				 fd;
77 	int				 delta_cache_fd;
78 	struct gotd_imsgev		 iev;
79 	struct gotd_imsgev		 repo_child_iev;
80 	struct event			 tmo;
81 	uid_t				 euid;
82 	gid_t				 egid;
83 	char				*packfile_path;
84 	char				*packidx_path;
85 	int				 nref_updates;
86 	int				 accept_flush_pkt;
87 	int				 flush_disconnect;
88 } gotd_session_client;
89 
90 void gotd_session_sighdlr(int sig, short event, void *arg);
91 static void gotd_session_shutdown(void);
92 
93 static void
94 disconnect(struct gotd_session_client *client)
95 {
96 	log_debug("uid %d: disconnecting", client->euid);
97 
98 	if (gotd_imsg_compose_event(&gotd_session.parent_iev,
99 	    GOTD_IMSG_DISCONNECT, gotd_session.proc_id, -1, NULL, 0) == -1)
100 		log_warn("imsg compose DISCONNECT");
101 
102 	imsg_clear(&client->repo_child_iev.ibuf);
103 	event_del(&client->repo_child_iev.ev);
104 	evtimer_del(&client->tmo);
105 	close(client->fd);
106 	if (client->delta_cache_fd != -1)
107 		close(client->delta_cache_fd);
108 	if (client->packfile_path) {
109 		if (unlink(client->packfile_path) == -1 && errno != ENOENT)
110 			log_warn("unlink %s: ", client->packfile_path);
111 		free(client->packfile_path);
112 	}
113 	if (client->packidx_path) {
114 		if (unlink(client->packidx_path) == -1 && errno != ENOENT)
115 			log_warn("unlink %s: ", client->packidx_path);
116 		free(client->packidx_path);
117 	}
118 	free(client->capabilities);
119 
120 	gotd_session_shutdown();
121 }
122 
123 static void
124 disconnect_on_error(struct gotd_session_client *client,
125     const struct got_error *err)
126 {
127 	struct imsgbuf ibuf;
128 
129 	if (err->code != GOT_ERR_EOF) {
130 		log_warnx("uid %d: %s", client->euid, err->msg);
131 		imsg_init(&ibuf, client->fd);
132 		gotd_imsg_send_error(&ibuf, 0, gotd_session.proc_id, err);
133 		imsg_clear(&ibuf);
134 	}
135 
136 	disconnect(client);
137 }
138 
139 static void
140 gotd_request_timeout(int fd, short events, void *arg)
141 {
142 	struct gotd_session_client *client = arg;
143 
144 	log_debug("disconnecting uid %d due to timeout", client->euid);
145 	disconnect(client);
146 }
147 
148 void
149 gotd_session_sighdlr(int sig, short event, void *arg)
150 {
151 	/*
152 	 * Normal signal handler rules don't apply because libevent
153 	 * decouples for us.
154 	 */
155 
156 	switch (sig) {
157 	case SIGHUP:
158 		log_info("%s: ignoring SIGHUP", __func__);
159 		break;
160 	case SIGUSR1:
161 		log_info("%s: ignoring SIGUSR1", __func__);
162 		break;
163 	case SIGTERM:
164 	case SIGINT:
165 		gotd_session_shutdown();
166 		/* NOTREACHED */
167 		break;
168 	default:
169 		fatalx("unexpected signal");
170 	}
171 }
172 
173 static const struct got_error *
174 recv_packfile_done(uint32_t *client_id, struct imsg *imsg)
175 {
176 	struct gotd_imsg_packfile_done idone;
177 	size_t datalen;
178 
179 	log_debug("packfile-done received");
180 
181 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
182 	if (datalen != sizeof(idone))
183 		return got_error(GOT_ERR_PRIVSEP_LEN);
184 	memcpy(&idone, imsg->data, sizeof(idone));
185 
186 	*client_id = idone.client_id;
187 	return NULL;
188 }
189 
190 static const struct got_error *
191 recv_packfile_install(uint32_t *client_id, struct imsg *imsg)
192 {
193 	struct gotd_imsg_packfile_install inst;
194 	size_t datalen;
195 
196 	log_debug("packfile-install received");
197 
198 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
199 	if (datalen != sizeof(inst))
200 		return got_error(GOT_ERR_PRIVSEP_LEN);
201 	memcpy(&inst, imsg->data, sizeof(inst));
202 
203 	*client_id = inst.client_id;
204 	return NULL;
205 }
206 
207 static const struct got_error *
208 recv_ref_updates_start(uint32_t *client_id, struct imsg *imsg)
209 {
210 	struct gotd_imsg_ref_updates_start istart;
211 	size_t datalen;
212 
213 	log_debug("ref-updates-start received");
214 
215 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
216 	if (datalen != sizeof(istart))
217 		return got_error(GOT_ERR_PRIVSEP_LEN);
218 	memcpy(&istart, imsg->data, sizeof(istart));
219 
220 	*client_id = istart.client_id;
221 	return NULL;
222 }
223 
224 static const struct got_error *
225 recv_ref_update(uint32_t *client_id, struct imsg *imsg)
226 {
227 	struct gotd_imsg_ref_update iref;
228 	size_t datalen;
229 
230 	log_debug("ref-update received");
231 
232 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
233 	if (datalen < sizeof(iref))
234 		return got_error(GOT_ERR_PRIVSEP_LEN);
235 	memcpy(&iref, imsg->data, sizeof(iref));
236 
237 	*client_id = iref.client_id;
238 	return NULL;
239 }
240 
241 static const struct got_error *
242 send_ref_update_ok(struct gotd_session_client *client,
243     struct gotd_imsg_ref_update *iref, const char *refname)
244 {
245 	struct gotd_imsg_ref_update_ok iok;
246 	struct gotd_imsgev *iev = &client->iev;
247 	struct ibuf *wbuf;
248 	size_t len;
249 
250 	memset(&iok, 0, sizeof(iok));
251 	iok.client_id = client->id;
252 	memcpy(iok.old_id, iref->old_id, SHA1_DIGEST_LENGTH);
253 	memcpy(iok.new_id, iref->new_id, SHA1_DIGEST_LENGTH);
254 	iok.name_len = strlen(refname);
255 
256 	len = sizeof(iok) + iok.name_len;
257 	wbuf = imsg_create(&iev->ibuf, GOTD_IMSG_REF_UPDATE_OK,
258 	    gotd_session.proc_id, gotd_session.pid, len);
259 	if (wbuf == NULL)
260 		return got_error_from_errno("imsg_create REF_UPDATE_OK");
261 
262 	if (imsg_add(wbuf, &iok, sizeof(iok)) == -1)
263 		return got_error_from_errno("imsg_add REF_UPDATE_OK");
264 	if (imsg_add(wbuf, refname, iok.name_len) == -1)
265 		return got_error_from_errno("imsg_add REF_UPDATE_OK");
266 
267 	wbuf->fd = -1;
268 	imsg_close(&iev->ibuf, wbuf);
269 	gotd_imsg_event_add(iev);
270 	return NULL;
271 }
272 
273 static void
274 send_refs_updated(struct gotd_session_client *client)
275 {
276 	if (gotd_imsg_compose_event(&client->iev, GOTD_IMSG_REFS_UPDATED,
277 	    gotd_session.proc_id, -1, NULL, 0) == -1)
278 		log_warn("imsg compose REFS_UPDATED");
279 }
280 
281 static const struct got_error *
282 send_ref_update_ng(struct gotd_session_client *client,
283     struct gotd_imsg_ref_update *iref, const char *refname,
284     const char *reason)
285 {
286 	const struct got_error *ng_err;
287 	struct gotd_imsg_ref_update_ng ing;
288 	struct gotd_imsgev *iev = &client->iev;
289 	struct ibuf *wbuf;
290 	size_t len;
291 
292 	memset(&ing, 0, sizeof(ing));
293 	ing.client_id = client->id;
294 	memcpy(ing.old_id, iref->old_id, SHA1_DIGEST_LENGTH);
295 	memcpy(ing.new_id, iref->new_id, SHA1_DIGEST_LENGTH);
296 	ing.name_len = strlen(refname);
297 
298 	ng_err = got_error_fmt(GOT_ERR_REF_BUSY, "%s", reason);
299 	ing.reason_len = strlen(ng_err->msg);
300 
301 	len = sizeof(ing) + ing.name_len + ing.reason_len;
302 	wbuf = imsg_create(&iev->ibuf, GOTD_IMSG_REF_UPDATE_NG,
303 	    gotd_session.proc_id, gotd_session.pid, len);
304 	if (wbuf == NULL)
305 		return got_error_from_errno("imsg_create REF_UPDATE_NG");
306 
307 	if (imsg_add(wbuf, &ing, sizeof(ing)) == -1)
308 		return got_error_from_errno("imsg_add REF_UPDATE_NG");
309 	if (imsg_add(wbuf, refname, ing.name_len) == -1)
310 		return got_error_from_errno("imsg_add REF_UPDATE_NG");
311 	if (imsg_add(wbuf, ng_err->msg, ing.reason_len) == -1)
312 		return got_error_from_errno("imsg_add REF_UPDATE_NG");
313 
314 	wbuf->fd = -1;
315 	imsg_close(&iev->ibuf, wbuf);
316 	gotd_imsg_event_add(iev);
317 	return NULL;
318 }
319 
320 static const struct got_error *
321 install_pack(struct gotd_session_client *client, const char *repo_path,
322     struct imsg *imsg)
323 {
324 	const struct got_error *err = NULL;
325 	struct gotd_imsg_packfile_install inst;
326 	char hex[SHA1_DIGEST_STRING_LENGTH];
327 	size_t datalen;
328 	char *packfile_path = NULL, *packidx_path = NULL;
329 
330 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
331 	if (datalen != sizeof(inst))
332 		return got_error(GOT_ERR_PRIVSEP_LEN);
333 	memcpy(&inst, imsg->data, sizeof(inst));
334 
335 	if (client->packfile_path == NULL)
336 		return got_error_msg(GOT_ERR_BAD_REQUEST,
337 		    "client has no pack file");
338 	if (client->packidx_path == NULL)
339 		return got_error_msg(GOT_ERR_BAD_REQUEST,
340 		    "client has no pack file index");
341 
342 	if (got_sha1_digest_to_str(inst.pack_sha1, hex, sizeof(hex)) == NULL)
343 		return got_error_msg(GOT_ERR_NO_SPACE,
344 		    "could not convert pack file SHA1 to hex");
345 
346 	if (asprintf(&packfile_path, "/%s/%s/pack-%s.pack",
347 	    repo_path, GOT_OBJECTS_PACK_DIR, hex) == -1) {
348 		err = got_error_from_errno("asprintf");
349 		goto done;
350 	}
351 
352 	if (asprintf(&packidx_path, "/%s/%s/pack-%s.idx",
353 	    repo_path, GOT_OBJECTS_PACK_DIR, hex) == -1) {
354 		err = got_error_from_errno("asprintf");
355 		goto done;
356 	}
357 
358 	if (rename(client->packfile_path, packfile_path) == -1) {
359 		err = got_error_from_errno3("rename", client->packfile_path,
360 		    packfile_path);
361 		goto done;
362 	}
363 
364 	free(client->packfile_path);
365 	client->packfile_path = NULL;
366 
367 	if (rename(client->packidx_path, packidx_path) == -1) {
368 		err = got_error_from_errno3("rename", client->packidx_path,
369 		    packidx_path);
370 		goto done;
371 	}
372 
373 	free(client->packidx_path);
374 	client->packidx_path = NULL;
375 done:
376 	free(packfile_path);
377 	free(packidx_path);
378 	return err;
379 }
380 
381 static const struct got_error *
382 begin_ref_updates(struct gotd_session_client *client, struct imsg *imsg)
383 {
384 	struct gotd_imsg_ref_updates_start istart;
385 	size_t datalen;
386 
387 	if (client->nref_updates != -1)
388 		return got_error(GOT_ERR_PRIVSEP_MSG);
389 
390 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
391 	if (datalen != sizeof(istart))
392 		return got_error(GOT_ERR_PRIVSEP_LEN);
393 	memcpy(&istart, imsg->data, sizeof(istart));
394 
395 	if (istart.nref_updates <= 0)
396 		return got_error(GOT_ERR_PRIVSEP_MSG);
397 
398 	client->nref_updates = istart.nref_updates;
399 	return NULL;
400 }
401 
402 static const struct got_error *
403 update_ref(int *shut, struct gotd_session_client *client,
404     const char *repo_path, struct imsg *imsg)
405 {
406 	const struct got_error *err = NULL;
407 	struct got_repository *repo = NULL;
408 	struct got_reference *ref = NULL;
409 	struct gotd_imsg_ref_update iref;
410 	struct got_object_id old_id, new_id;
411 	struct got_object_id *id = NULL;
412 	char *refname = NULL;
413 	size_t datalen;
414 	int locked = 0;
415 	char hex1[SHA1_DIGEST_STRING_LENGTH];
416 	char hex2[SHA1_DIGEST_STRING_LENGTH];
417 
418 	log_debug("update-ref from uid %d", client->euid);
419 
420 	if (client->nref_updates <= 0)
421 		return got_error(GOT_ERR_PRIVSEP_MSG);
422 
423 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
424 	if (datalen < sizeof(iref))
425 		return got_error(GOT_ERR_PRIVSEP_LEN);
426 	memcpy(&iref, imsg->data, sizeof(iref));
427 	if (datalen != sizeof(iref) + iref.name_len)
428 		return got_error(GOT_ERR_PRIVSEP_LEN);
429 	refname = strndup(imsg->data + sizeof(iref), iref.name_len);
430 	if (refname == NULL)
431 		return got_error_from_errno("strndup");
432 
433 	log_debug("updating ref %s for uid %d", refname, client->euid);
434 
435 	err = got_repo_open(&repo, repo_path, NULL, NULL);
436 	if (err)
437 		goto done;
438 
439 	memcpy(old_id.sha1, iref.old_id, SHA1_DIGEST_LENGTH);
440 	memcpy(new_id.sha1, iref.new_id, SHA1_DIGEST_LENGTH);
441 	err = got_repo_find_object_id(iref.delete_ref ? &old_id : &new_id,
442 	    repo);
443 	if (err)
444 		goto done;
445 
446 	if (iref.ref_is_new) {
447 		err = got_ref_open(&ref, repo, refname, 0);
448 		if (err) {
449 			if (err->code != GOT_ERR_NOT_REF)
450 				goto done;
451 			err = got_ref_alloc(&ref, refname, &new_id);
452 			if (err)
453 				goto done;
454 			err = got_ref_write(ref, repo); /* will lock/unlock */
455 			if (err)
456 				goto done;
457 		} else {
458 			err = got_ref_resolve(&id, repo, ref);
459 			if (err)
460 				goto done;
461 			got_object_id_hex(&new_id, hex1, sizeof(hex1));
462 			got_object_id_hex(id, hex2, sizeof(hex2));
463 			err = got_error_fmt(GOT_ERR_REF_BUSY,
464 			    "Addition %s: %s failed; %s: %s has been "
465 			    "created by someone else while transaction "
466 			    "was in progress",
467 			    got_ref_get_name(ref), hex1,
468 			    got_ref_get_name(ref), hex2);
469 			goto done;
470 		}
471 	} else if (iref.delete_ref) {
472 		err = got_ref_open(&ref, repo, refname, 1 /* lock */);
473 		if (err)
474 			goto done;
475 		locked = 1;
476 
477 		err = got_ref_resolve(&id, repo, ref);
478 		if (err)
479 			goto done;
480 
481 		if (got_object_id_cmp(id, &old_id) != 0) {
482 			got_object_id_hex(&old_id, hex1, sizeof(hex1));
483 			got_object_id_hex(id, hex2, sizeof(hex2));
484 			err = got_error_fmt(GOT_ERR_REF_BUSY,
485 			    "Deletion %s: %s failed; %s: %s has been "
486 			    "created by someone else while transaction "
487 			    "was in progress",
488 			    got_ref_get_name(ref), hex1,
489 			    got_ref_get_name(ref), hex2);
490 			goto done;
491 		}
492 
493 		err = got_ref_delete(ref, repo);
494 		if (err)
495 			goto done;
496 
497 		free(id);
498 		id = NULL;
499 	} else {
500 		err = got_ref_open(&ref, repo, refname, 1 /* lock */);
501 		if (err)
502 			goto done;
503 		locked = 1;
504 
505 		err = got_ref_resolve(&id, repo, ref);
506 		if (err)
507 			goto done;
508 
509 		if (got_object_id_cmp(id, &old_id) != 0) {
510 			got_object_id_hex(&old_id, hex1, sizeof(hex1));
511 			got_object_id_hex(id, hex2, sizeof(hex2));
512 			err = got_error_fmt(GOT_ERR_REF_BUSY,
513 			    "Update %s: %s failed; %s: %s has been "
514 			    "created by someone else while transaction "
515 			    "was in progress",
516 			    got_ref_get_name(ref), hex1,
517 			    got_ref_get_name(ref), hex2);
518 			goto done;
519 		}
520 
521 		if (got_object_id_cmp(&new_id, &old_id) != 0) {
522 			err = got_ref_change_ref(ref, &new_id);
523 			if (err)
524 				goto done;
525 
526 			err = got_ref_write(ref, repo);
527 			if (err)
528 				goto done;
529 		}
530 
531 		free(id);
532 		id = NULL;
533 	}
534 done:
535 	if (err) {
536 		if (err->code == GOT_ERR_LOCKFILE_TIMEOUT) {
537 			err = got_error_fmt(GOT_ERR_LOCKFILE_TIMEOUT,
538 			    "could not acquire exclusive file lock for %s",
539 			    refname);
540 		}
541 		send_ref_update_ng(client, &iref, refname, err->msg);
542 	} else
543 		send_ref_update_ok(client, &iref, refname);
544 
545 	if (client->nref_updates > 0) {
546 		client->nref_updates--;
547 		if (client->nref_updates == 0) {
548 			send_refs_updated(client);
549 			client->flush_disconnect = 1;
550 		}
551 
552 	}
553 	if (locked) {
554 		const struct got_error *unlock_err;
555 		unlock_err = got_ref_unlock(ref);
556 		if (unlock_err && err == NULL)
557 			err = unlock_err;
558 	}
559 	if (ref)
560 		got_ref_close(ref);
561 	if (repo)
562 		got_repo_close(repo);
563 	free(refname);
564 	free(id);
565 	return err;
566 }
567 
568 static void
569 session_dispatch_repo_child(int fd, short event, void *arg)
570 {
571 	struct gotd_imsgev *iev = arg;
572 	struct imsgbuf *ibuf = &iev->ibuf;
573 	struct gotd_session_client *client = &gotd_session_client;
574 	ssize_t n;
575 	int shut = 0;
576 	struct imsg imsg;
577 
578 	if (event & EV_READ) {
579 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
580 			fatal("imsg_read error");
581 		if (n == 0) {
582 			/* Connection closed. */
583 			shut = 1;
584 			goto done;
585 		}
586 	}
587 
588 	if (event & EV_WRITE) {
589 		n = msgbuf_write(&ibuf->w);
590 		if (n == -1 && errno != EAGAIN)
591 			fatal("msgbuf_write");
592 		if (n == 0) {
593 			/* Connection closed. */
594 			shut = 1;
595 			goto done;
596 		}
597 	}
598 
599 	for (;;) {
600 		const struct got_error *err = NULL;
601 		uint32_t client_id = 0;
602 		int do_disconnect = 0;
603 		int do_ref_updates = 0, do_ref_update = 0;
604 		int do_packfile_install = 0;
605 
606 		if ((n = imsg_get(ibuf, &imsg)) == -1)
607 			fatal("%s: imsg_get error", __func__);
608 		if (n == 0)	/* No more messages. */
609 			break;
610 
611 		switch (imsg.hdr.type) {
612 		case GOTD_IMSG_ERROR:
613 			do_disconnect = 1;
614 			err = gotd_imsg_recv_error(&client_id, &imsg);
615 			break;
616 		case GOTD_IMSG_PACKFILE_DONE:
617 			do_disconnect = 1;
618 			err = recv_packfile_done(&client_id, &imsg);
619 			break;
620 		case GOTD_IMSG_PACKFILE_INSTALL:
621 			err = recv_packfile_install(&client_id, &imsg);
622 			if (err == NULL)
623 				do_packfile_install = 1;
624 			break;
625 		case GOTD_IMSG_REF_UPDATES_START:
626 			err = recv_ref_updates_start(&client_id, &imsg);
627 			if (err == NULL)
628 				do_ref_updates = 1;
629 			break;
630 		case GOTD_IMSG_REF_UPDATE:
631 			err = recv_ref_update(&client_id, &imsg);
632 			if (err == NULL)
633 				do_ref_update = 1;
634 			break;
635 		default:
636 			log_debug("unexpected imsg %d", imsg.hdr.type);
637 			break;
638 		}
639 
640 		if (do_disconnect) {
641 			if (err)
642 				disconnect_on_error(client, err);
643 			else
644 				disconnect(client);
645 		} else {
646 			if (do_packfile_install)
647 				err = install_pack(client,
648 				    gotd_session.repo->path, &imsg);
649 			else if (do_ref_updates)
650 				err = begin_ref_updates(client, &imsg);
651 			else if (do_ref_update)
652 				err = update_ref(&shut, client,
653 				    gotd_session.repo->path, &imsg);
654 			if (err)
655 				log_warnx("uid %d: %s", client->euid, err->msg);
656 		}
657 		imsg_free(&imsg);
658 	}
659 done:
660 	if (!shut) {
661 		gotd_imsg_event_add(iev);
662 	} else {
663 		/* This pipe is dead. Remove its event handler */
664 		event_del(&iev->ev);
665 		event_loopexit(NULL);
666 	}
667 }
668 
669 static const struct got_error *
670 recv_capabilities(struct gotd_session_client *client, struct imsg *imsg)
671 {
672 	struct gotd_imsg_capabilities icapas;
673 	size_t datalen;
674 
675 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
676 	if (datalen != sizeof(icapas))
677 		return got_error(GOT_ERR_PRIVSEP_LEN);
678 	memcpy(&icapas, imsg->data, sizeof(icapas));
679 
680 	client->ncapa_alloc = icapas.ncapabilities;
681 	client->capabilities = calloc(client->ncapa_alloc,
682 	    sizeof(*client->capabilities));
683 	if (client->capabilities == NULL) {
684 		client->ncapa_alloc = 0;
685 		return got_error_from_errno("calloc");
686 	}
687 
688 	log_debug("expecting %zu capabilities from uid %d",
689 	    client->ncapa_alloc, client->euid);
690 	return NULL;
691 }
692 
693 static const struct got_error *
694 recv_capability(struct gotd_session_client *client, struct imsg *imsg)
695 {
696 	struct gotd_imsg_capability icapa;
697 	struct gotd_client_capability *capa;
698 	size_t datalen;
699 	char *key, *value = NULL;
700 
701 	if (client->capabilities == NULL ||
702 	    client->ncapabilities >= client->ncapa_alloc) {
703 		return got_error_msg(GOT_ERR_BAD_REQUEST,
704 		    "unexpected capability received");
705 	}
706 
707 	memset(&icapa, 0, sizeof(icapa));
708 
709 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
710 	if (datalen < sizeof(icapa))
711 		return got_error(GOT_ERR_PRIVSEP_LEN);
712 	memcpy(&icapa, imsg->data, sizeof(icapa));
713 
714 	if (datalen != sizeof(icapa) + icapa.key_len + icapa.value_len)
715 		return got_error(GOT_ERR_PRIVSEP_LEN);
716 
717 	key = strndup(imsg->data + sizeof(icapa), icapa.key_len);
718 	if (key == NULL)
719 		return got_error_from_errno("strndup");
720 	if (icapa.value_len > 0) {
721 		value = strndup(imsg->data + sizeof(icapa) + icapa.key_len,
722 		    icapa.value_len);
723 		if (value == NULL) {
724 			free(key);
725 			return got_error_from_errno("strndup");
726 		}
727 	}
728 
729 	capa = &client->capabilities[client->ncapabilities++];
730 	capa->key = key;
731 	capa->value = value;
732 
733 	if (value)
734 		log_debug("uid %d: capability %s=%s", client->euid, key, value);
735 	else
736 		log_debug("uid %d: capability %s", client->euid, key);
737 
738 	return NULL;
739 }
740 
741 static const struct got_error *
742 ensure_client_is_reading(struct gotd_session_client *client)
743 {
744 	if (client->is_writing) {
745 		return got_error_fmt(GOT_ERR_BAD_PACKET,
746 		    "uid %d made a read-request but is not reading from "
747 		    "a repository", client->euid);
748 	}
749 
750 	return NULL;
751 }
752 
753 static const struct got_error *
754 ensure_client_is_writing(struct gotd_session_client *client)
755 {
756 	if (!client->is_writing) {
757 		return got_error_fmt(GOT_ERR_BAD_PACKET,
758 		    "uid %d made a write-request but is not writing to "
759 		    "a repository", client->euid);
760 	}
761 
762 	return NULL;
763 }
764 
765 static const struct got_error *
766 forward_want(struct gotd_session_client *client, struct imsg *imsg)
767 {
768 	struct gotd_imsg_want ireq;
769 	struct gotd_imsg_want iwant;
770 	size_t datalen;
771 
772 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
773 	if (datalen != sizeof(ireq))
774 		return got_error(GOT_ERR_PRIVSEP_LEN);
775 
776 	memcpy(&ireq, imsg->data, datalen);
777 
778 	memset(&iwant, 0, sizeof(iwant));
779 	memcpy(iwant.object_id, ireq.object_id, SHA1_DIGEST_LENGTH);
780 	iwant.client_id = client->id;
781 
782 	if (gotd_imsg_compose_event(&client->repo_child_iev, GOTD_IMSG_WANT,
783 	    gotd_session.proc_id, -1, &iwant, sizeof(iwant)) == -1)
784 		return got_error_from_errno("imsg compose WANT");
785 
786 	return NULL;
787 }
788 
789 static const struct got_error *
790 forward_ref_update(struct gotd_session_client *client, struct imsg *imsg)
791 {
792 	const struct got_error *err = NULL;
793 	struct gotd_imsg_ref_update ireq;
794 	struct gotd_imsg_ref_update *iref = NULL;
795 	size_t datalen;
796 
797 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
798 	if (datalen < sizeof(ireq))
799 		return got_error(GOT_ERR_PRIVSEP_LEN);
800 	memcpy(&ireq, imsg->data, sizeof(ireq));
801 	if (datalen != sizeof(ireq) + ireq.name_len)
802 		return got_error(GOT_ERR_PRIVSEP_LEN);
803 
804 	iref = malloc(datalen);
805 	if (iref == NULL)
806 		return got_error_from_errno("malloc");
807 	memcpy(iref, imsg->data, datalen);
808 
809 	iref->client_id = client->id;
810 	if (gotd_imsg_compose_event(&client->repo_child_iev,
811 	    GOTD_IMSG_REF_UPDATE, gotd_session.proc_id, -1,
812 	    iref, datalen) == -1)
813 		err = got_error_from_errno("imsg compose REF_UPDATE");
814 	free(iref);
815 	return err;
816 }
817 
818 static const struct got_error *
819 forward_have(struct gotd_session_client *client, struct imsg *imsg)
820 {
821 	struct gotd_imsg_have ireq;
822 	struct gotd_imsg_have ihave;
823 	size_t datalen;
824 
825 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
826 	if (datalen != sizeof(ireq))
827 		return got_error(GOT_ERR_PRIVSEP_LEN);
828 
829 	memcpy(&ireq, imsg->data, datalen);
830 
831 	memset(&ihave, 0, sizeof(ihave));
832 	memcpy(ihave.object_id, ireq.object_id, SHA1_DIGEST_LENGTH);
833 	ihave.client_id = client->id;
834 
835 	if (gotd_imsg_compose_event(&client->repo_child_iev, GOTD_IMSG_HAVE,
836 	    gotd_session.proc_id, -1, &ihave, sizeof(ihave)) == -1)
837 		return got_error_from_errno("imsg compose HAVE");
838 
839 	return NULL;
840 }
841 
842 static int
843 client_has_capability(struct gotd_session_client *client, const char *capastr)
844 {
845 	struct gotd_client_capability *capa;
846 	size_t i;
847 
848 	if (client->ncapabilities == 0)
849 		return 0;
850 
851 	for (i = 0; i < client->ncapabilities; i++) {
852 		capa = &client->capabilities[i];
853 		if (strcmp(capa->key, capastr) == 0)
854 			return 1;
855 	}
856 
857 	return 0;
858 }
859 
860 static const struct got_error *
861 recv_packfile(struct gotd_session_client *client)
862 {
863 	const struct got_error *err = NULL;
864 	struct gotd_imsg_recv_packfile ipack;
865 	struct gotd_imsg_packfile_pipe ipipe;
866 	struct gotd_imsg_packidx_file ifile;
867 	char *basepath = NULL, *pack_path = NULL, *idx_path = NULL;
868 	int packfd = -1, idxfd = -1;
869 	int pipe[2] = { -1, -1 };
870 
871 	if (client->packfile_path) {
872 		return got_error_fmt(GOT_ERR_PRIVSEP_MSG,
873 		    "uid %d already has a pack file", client->euid);
874 	}
875 
876 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pipe) == -1)
877 		return got_error_from_errno("socketpair");
878 
879 	memset(&ipipe, 0, sizeof(ipipe));
880 	ipipe.client_id = client->id;
881 
882 	/* Send pack pipe end 0 to repo child process. */
883 	if (gotd_imsg_compose_event(&client->repo_child_iev,
884 	    GOTD_IMSG_PACKFILE_PIPE, gotd_session.proc_id, pipe[0],
885 	        &ipipe, sizeof(ipipe)) == -1) {
886 		err = got_error_from_errno("imsg compose PACKFILE_PIPE");
887 		pipe[0] = -1;
888 		goto done;
889 	}
890 	pipe[0] = -1;
891 
892 	/* Send pack pipe end 1 to gotsh(1) (expects just an fd, no data). */
893 	if (gotd_imsg_compose_event(&client->iev,
894 	    GOTD_IMSG_PACKFILE_PIPE, gotd_session.proc_id, pipe[1],
895 	    NULL, 0) == -1)
896 		err = got_error_from_errno("imsg compose PACKFILE_PIPE");
897 	pipe[1] = -1;
898 
899 	if (asprintf(&basepath, "%s/%s/receiving-from-uid-%d.pack",
900 	    got_repo_get_path(gotd_session.repo), GOT_OBJECTS_PACK_DIR,
901 	    client->euid) == -1) {
902 		err = got_error_from_errno("asprintf");
903 		goto done;
904 	}
905 
906 	err = got_opentemp_named_fd(&pack_path, &packfd, basepath, "");
907 	if (err)
908 		goto done;
909 	if (fchmod(packfd, GOT_DEFAULT_PACK_MODE) == -1) {
910 		err = got_error_from_errno2("fchmod", pack_path);
911 		goto done;
912 	}
913 
914 	free(basepath);
915 	if (asprintf(&basepath, "%s/%s/receiving-from-uid-%d.idx",
916 	    got_repo_get_path(gotd_session.repo), GOT_OBJECTS_PACK_DIR,
917 	    client->euid) == -1) {
918 		err = got_error_from_errno("asprintf");
919 		basepath = NULL;
920 		goto done;
921 	}
922 	err = got_opentemp_named_fd(&idx_path, &idxfd, basepath, "");
923 	if (err)
924 		goto done;
925 	if (fchmod(idxfd, GOT_DEFAULT_PACK_MODE) == -1) {
926 		err = got_error_from_errno2("fchmod", idx_path);
927 		goto done;
928 	}
929 
930 	memset(&ifile, 0, sizeof(ifile));
931 	ifile.client_id = client->id;
932 	if (gotd_imsg_compose_event(&client->repo_child_iev,
933 	    GOTD_IMSG_PACKIDX_FILE, gotd_session.proc_id,
934 	    idxfd, &ifile, sizeof(ifile)) == -1) {
935 		err = got_error_from_errno("imsg compose PACKIDX_FILE");
936 		idxfd = -1;
937 		goto done;
938 	}
939 	idxfd = -1;
940 
941 	memset(&ipack, 0, sizeof(ipack));
942 	ipack.client_id = client->id;
943 	if (client_has_capability(client, GOT_CAPA_REPORT_STATUS))
944 		ipack.report_status = 1;
945 
946 	if (gotd_imsg_compose_event(&client->repo_child_iev,
947 	    GOTD_IMSG_RECV_PACKFILE, gotd_session.proc_id, packfd,
948 	    &ipack, sizeof(ipack)) == -1) {
949 		err = got_error_from_errno("imsg compose RECV_PACKFILE");
950 		packfd = -1;
951 		goto done;
952 	}
953 	packfd = -1;
954 
955 done:
956 	free(basepath);
957 	if (pipe[0] != -1 && close(pipe[0]) == -1 && err == NULL)
958 		err = got_error_from_errno("close");
959 	if (pipe[1] != -1 && close(pipe[1]) == -1 && err == NULL)
960 		err = got_error_from_errno("close");
961 	if (packfd != -1 && close(packfd) == -1 && err == NULL)
962 		err = got_error_from_errno("close");
963 	if (idxfd != -1 && close(idxfd) == -1 && err == NULL)
964 		err = got_error_from_errno("close");
965 	if (err) {
966 		free(pack_path);
967 		free(idx_path);
968 	} else {
969 		client->packfile_path = pack_path;
970 		client->packidx_path = idx_path;
971 	}
972 	return err;
973 }
974 
975 static const struct got_error *
976 send_packfile(struct gotd_session_client *client)
977 {
978 	const struct got_error *err = NULL;
979 	struct gotd_imsg_send_packfile ipack;
980 	struct gotd_imsg_packfile_pipe ipipe;
981 	int pipe[2];
982 
983 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pipe) == -1)
984 		return got_error_from_errno("socketpair");
985 
986 	memset(&ipack, 0, sizeof(ipack));
987 	memset(&ipipe, 0, sizeof(ipipe));
988 
989 	ipack.client_id = client->id;
990 	if (client_has_capability(client, GOT_CAPA_SIDE_BAND_64K))
991 		ipack.report_progress = 1;
992 
993 	client->delta_cache_fd = got_opentempfd();
994 	if (client->delta_cache_fd == -1)
995 		return got_error_from_errno("got_opentempfd");
996 
997 	if (gotd_imsg_compose_event(&client->repo_child_iev,
998 	    GOTD_IMSG_SEND_PACKFILE, PROC_GOTD, client->delta_cache_fd,
999 	    &ipack, sizeof(ipack)) == -1) {
1000 		err = got_error_from_errno("imsg compose SEND_PACKFILE");
1001 		close(pipe[0]);
1002 		close(pipe[1]);
1003 		return err;
1004 	}
1005 
1006 	ipipe.client_id = client->id;
1007 
1008 	/* Send pack pipe end 0 to repo child process. */
1009 	if (gotd_imsg_compose_event(&client->repo_child_iev,
1010 	    GOTD_IMSG_PACKFILE_PIPE, PROC_GOTD,
1011 	    pipe[0], &ipipe, sizeof(ipipe)) == -1) {
1012 		err = got_error_from_errno("imsg compose PACKFILE_PIPE");
1013 		close(pipe[1]);
1014 		return err;
1015 	}
1016 
1017 	/* Send pack pipe end 1 to gotsh(1) (expects just an fd, no data). */
1018 	if (gotd_imsg_compose_event(&client->iev,
1019 	    GOTD_IMSG_PACKFILE_PIPE, PROC_GOTD, pipe[1], NULL, 0) == -1)
1020 		err = got_error_from_errno("imsg compose PACKFILE_PIPE");
1021 
1022 	return err;
1023 }
1024 
1025 static void
1026 session_dispatch_client(int fd, short events, void *arg)
1027 {
1028 	struct gotd_imsgev *iev = arg;
1029 	struct imsgbuf *ibuf = &iev->ibuf;
1030 	struct gotd_session_client *client = &gotd_session_client;
1031 	const struct got_error *err = NULL;
1032 	struct imsg imsg;
1033 	ssize_t n;
1034 
1035 	if (events & EV_WRITE) {
1036 		while (ibuf->w.queued) {
1037 			n = msgbuf_write(&ibuf->w);
1038 			if (n == -1 && errno == EPIPE) {
1039 				/*
1040 				 * The client has closed its socket.
1041 				 * This can happen when Git clients are
1042 				 * done sending pack file data.
1043 				 */
1044 				msgbuf_clear(&ibuf->w);
1045 				continue;
1046 			} else if (n == -1 && errno != EAGAIN) {
1047 				err = got_error_from_errno("imsg_flush");
1048 				disconnect_on_error(client, err);
1049 				return;
1050 			}
1051 			if (n == 0) {
1052 				/* Connection closed. */
1053 				err = got_error(GOT_ERR_EOF);
1054 				disconnect_on_error(client, err);
1055 				return;
1056 			}
1057 		}
1058 
1059 		if (client->flush_disconnect) {
1060 			disconnect(client);
1061 			return;
1062 		}
1063 	}
1064 
1065 	if ((events & EV_READ) == 0)
1066 		return;
1067 
1068 	memset(&imsg, 0, sizeof(imsg));
1069 
1070 	while (err == NULL) {
1071 		err = gotd_imsg_recv(&imsg, ibuf, 0);
1072 		if (err) {
1073 			if (err->code == GOT_ERR_PRIVSEP_READ)
1074 				err = NULL;
1075 			else if (err->code == GOT_ERR_EOF &&
1076 			    client->state == GOTD_STATE_EXPECT_CAPABILITIES) {
1077 				/*
1078 				 * The client has closed its socket before
1079 				 * sending its capability announcement.
1080 				 * This can happen when Git clients have
1081 				 * no ref-updates to send.
1082 				 */
1083 				disconnect_on_error(client, err);
1084 				return;
1085 			}
1086 			break;
1087 		}
1088 
1089 		evtimer_del(&client->tmo);
1090 
1091 		switch (imsg.hdr.type) {
1092 		case GOTD_IMSG_CAPABILITIES:
1093 			if (client->state != GOTD_STATE_EXPECT_CAPABILITIES) {
1094 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1095 				    "unexpected capabilities received");
1096 				break;
1097 			}
1098 			log_debug("receiving capabilities from uid %d",
1099 			    client->euid);
1100 			err = recv_capabilities(client, &imsg);
1101 			break;
1102 		case GOTD_IMSG_CAPABILITY:
1103 			if (client->state != GOTD_STATE_EXPECT_CAPABILITIES) {
1104 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1105 				    "unexpected capability received");
1106 				break;
1107 			}
1108 			err = recv_capability(client, &imsg);
1109 			if (err || client->ncapabilities < client->ncapa_alloc)
1110 				break;
1111 			if (!client->is_writing) {
1112 				client->state = GOTD_STATE_EXPECT_WANT;
1113 				client->accept_flush_pkt = 1;
1114 				log_debug("uid %d: expecting want-lines",
1115 				    client->euid);
1116 			} else if (client->is_writing) {
1117 				client->state = GOTD_STATE_EXPECT_REF_UPDATE;
1118 				client->accept_flush_pkt = 1;
1119 				log_debug("uid %d: expecting ref-update-lines",
1120 				    client->euid);
1121 			} else
1122 				fatalx("client %d is both reading and writing",
1123 				    client->euid);
1124 			break;
1125 		case GOTD_IMSG_WANT:
1126 			if (client->state != GOTD_STATE_EXPECT_WANT) {
1127 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1128 				    "unexpected want-line received");
1129 				break;
1130 			}
1131 			log_debug("received want-line from uid %d",
1132 			    client->euid);
1133 			err = ensure_client_is_reading(client);
1134 			if (err)
1135 				break;
1136 			client->accept_flush_pkt = 1;
1137 			err = forward_want(client, &imsg);
1138 			break;
1139 		case GOTD_IMSG_REF_UPDATE:
1140 			if (client->state != GOTD_STATE_EXPECT_REF_UPDATE &&
1141 			    client->state !=
1142 			    GOTD_STATE_EXPECT_MORE_REF_UPDATES) {
1143 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1144 				    "unexpected ref-update-line received");
1145 				break;
1146 			}
1147 			log_debug("received ref-update-line from uid %d",
1148 			    client->euid);
1149 			err = ensure_client_is_writing(client);
1150 			if (err)
1151 				break;
1152 			err = forward_ref_update(client, &imsg);
1153 			if (err)
1154 				break;
1155 			client->state = GOTD_STATE_EXPECT_MORE_REF_UPDATES;
1156 			client->accept_flush_pkt = 1;
1157 			break;
1158 		case GOTD_IMSG_HAVE:
1159 			if (client->state != GOTD_STATE_EXPECT_HAVE) {
1160 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1161 				    "unexpected have-line received");
1162 				break;
1163 			}
1164 			log_debug("received have-line from uid %d",
1165 			    client->euid);
1166 			err = ensure_client_is_reading(client);
1167 			if (err)
1168 				break;
1169 			err = forward_have(client, &imsg);
1170 			if (err)
1171 				break;
1172 			client->accept_flush_pkt = 1;
1173 			break;
1174 		case GOTD_IMSG_FLUSH:
1175 			if (client->state == GOTD_STATE_EXPECT_WANT ||
1176 			    client->state == GOTD_STATE_EXPECT_HAVE) {
1177 				err = ensure_client_is_reading(client);
1178 				if (err)
1179 					break;
1180 			} else if (client->state ==
1181 			    GOTD_STATE_EXPECT_MORE_REF_UPDATES) {
1182 				err = ensure_client_is_writing(client);
1183 				if (err)
1184 					break;
1185 			} else if (client->state != GOTD_STATE_EXPECT_DONE) {
1186 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1187 				    "unexpected flush-pkt received");
1188 				break;
1189 			}
1190 			if (!client->accept_flush_pkt) {
1191 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1192 				    "unexpected flush-pkt received");
1193 				break;
1194 			}
1195 
1196 			/*
1197 			 * Accept just one flush packet at a time.
1198 			 * Future client state transitions will set this flag
1199 			 * again if another flush packet is expected.
1200 			 */
1201 			client->accept_flush_pkt = 0;
1202 
1203 			log_debug("received flush-pkt from uid %d",
1204 			    client->euid);
1205 			if (client->state == GOTD_STATE_EXPECT_WANT) {
1206 				client->state = GOTD_STATE_EXPECT_HAVE;
1207 				log_debug("uid %d: expecting have-lines",
1208 				    client->euid);
1209 			} else if (client->state == GOTD_STATE_EXPECT_HAVE) {
1210 				client->state = GOTD_STATE_EXPECT_DONE;
1211 				client->accept_flush_pkt = 1;
1212 				log_debug("uid %d: expecting 'done'",
1213 				    client->euid);
1214 			} else if (client->state ==
1215 			    GOTD_STATE_EXPECT_MORE_REF_UPDATES) {
1216 				client->state = GOTD_STATE_EXPECT_PACKFILE;
1217 				log_debug("uid %d: expecting packfile",
1218 				    client->euid);
1219 				err = recv_packfile(client);
1220 			} else if (client->state != GOTD_STATE_EXPECT_DONE) {
1221 				/* should not happen, see above */
1222 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1223 				    "unexpected client state");
1224 				break;
1225 			}
1226 			break;
1227 		case GOTD_IMSG_DONE:
1228 			if (client->state != GOTD_STATE_EXPECT_HAVE &&
1229 			    client->state != GOTD_STATE_EXPECT_DONE) {
1230 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1231 				    "unexpected flush-pkt received");
1232 				break;
1233 			}
1234 			log_debug("received 'done' from uid %d", client->euid);
1235 			err = ensure_client_is_reading(client);
1236 			if (err)
1237 				break;
1238 			client->state = GOTD_STATE_DONE;
1239 			client->accept_flush_pkt = 1;
1240 			err = send_packfile(client);
1241 			break;
1242 		default:
1243 			log_debug("unexpected imsg %d", imsg.hdr.type);
1244 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1245 			break;
1246 		}
1247 
1248 		imsg_free(&imsg);
1249 	}
1250 
1251 	if (err) {
1252 		if (err->code != GOT_ERR_EOF ||
1253 		    client->state != GOTD_STATE_EXPECT_PACKFILE)
1254 			disconnect_on_error(client, err);
1255 	} else {
1256 		gotd_imsg_event_add(iev);
1257 		evtimer_add(&client->tmo, &gotd_session.request_timeout);
1258 	}
1259 }
1260 
1261 static const struct got_error *
1262 list_refs_request(void)
1263 {
1264 	static const struct got_error *err;
1265 	struct gotd_session_client *client = &gotd_session_client;
1266 	struct gotd_imsgev *iev = &client->repo_child_iev;
1267 	struct gotd_imsg_list_refs_internal ilref;
1268 	int fd;
1269 
1270 	if (client->state != GOTD_STATE_EXPECT_LIST_REFS)
1271 		return got_error(GOT_ERR_PRIVSEP_MSG);
1272 
1273 	memset(&ilref, 0, sizeof(ilref));
1274 	ilref.client_id = client->id;
1275 
1276 	fd = dup(client->fd);
1277 	if (fd == -1)
1278 		return got_error_from_errno("dup");
1279 
1280 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_LIST_REFS_INTERNAL,
1281 	    gotd_session.proc_id, fd, &ilref, sizeof(ilref)) == -1) {
1282 		err = got_error_from_errno("imsg compose LIST_REFS_INTERNAL");
1283 		close(fd);
1284 		return err;
1285 	}
1286 
1287 	client->state = GOTD_STATE_EXPECT_CAPABILITIES;
1288 	log_debug("uid %d: expecting capabilities", client->euid);
1289 	return NULL;
1290 }
1291 
1292 static const struct got_error *
1293 recv_connect(struct imsg *imsg)
1294 {
1295 	struct gotd_session_client *client = &gotd_session_client;
1296 	struct gotd_imsg_connect iconnect;
1297 	size_t datalen;
1298 
1299 	if (client->state != GOTD_STATE_EXPECT_LIST_REFS)
1300 		return got_error(GOT_ERR_PRIVSEP_MSG);
1301 
1302 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1303 	if (datalen != sizeof(iconnect))
1304 		return got_error(GOT_ERR_PRIVSEP_LEN);
1305 	memcpy(&iconnect, imsg->data, sizeof(iconnect));
1306 
1307 	if (imsg->fd == -1)
1308 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
1309 
1310 	client->fd = imsg->fd;
1311 	client->euid = iconnect.euid;
1312 	client->egid = iconnect.egid;
1313 
1314 	imsg_init(&client->iev.ibuf, client->fd);
1315 	client->iev.handler = session_dispatch_client;
1316 	client->iev.events = EV_READ;
1317 	client->iev.handler_arg = NULL;
1318 	event_set(&client->iev.ev, client->iev.ibuf.fd, EV_READ,
1319 	    session_dispatch_client, &client->iev);
1320 	gotd_imsg_event_add(&client->iev);
1321 	evtimer_set(&client->tmo, gotd_request_timeout, client);
1322 
1323 	return NULL;
1324 }
1325 
1326 static const struct got_error *
1327 recv_repo_child(struct imsg *imsg)
1328 {
1329 	struct gotd_imsg_connect_repo_child ichild;
1330 	struct gotd_session_client *client = &gotd_session_client;
1331 	size_t datalen;
1332 
1333 	if (client->state != GOTD_STATE_EXPECT_LIST_REFS)
1334 		return got_error(GOT_ERR_PRIVSEP_MSG);
1335 
1336 	/* We should already have received a pipe to the listener. */
1337 	if (client->fd == -1)
1338 		return got_error(GOT_ERR_PRIVSEP_MSG);
1339 
1340 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1341 	if (datalen != sizeof(ichild))
1342 		return got_error(GOT_ERR_PRIVSEP_LEN);
1343 
1344 	memcpy(&ichild, imsg->data, sizeof(ichild));
1345 
1346 	client->id = ichild.client_id;
1347 	if (ichild.proc_id == PROC_REPO_WRITE)
1348 		client->is_writing = 1;
1349 	else if (ichild.proc_id == PROC_REPO_READ)
1350 		client->is_writing = 0;
1351 	else
1352 		return got_error_msg(GOT_ERR_PRIVSEP_MSG,
1353 		    "bad child process type");
1354 
1355 	if (imsg->fd == -1)
1356 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
1357 
1358 	imsg_init(&client->repo_child_iev.ibuf, imsg->fd);
1359 	client->repo_child_iev.handler = session_dispatch_repo_child;
1360 	client->repo_child_iev.events = EV_READ;
1361 	client->repo_child_iev.handler_arg = NULL;
1362 	event_set(&client->repo_child_iev.ev, client->repo_child_iev.ibuf.fd,
1363 	    EV_READ, session_dispatch_repo_child, &client->repo_child_iev);
1364 	gotd_imsg_event_add(&client->repo_child_iev);
1365 
1366 	/* The "recvfd" pledge promise is no longer needed. */
1367 	if (pledge("stdio rpath wpath cpath sendfd fattr flock", NULL) == -1)
1368 		fatal("pledge");
1369 
1370 	return NULL;
1371 }
1372 
1373 static void
1374 session_dispatch(int fd, short event, void *arg)
1375 {
1376 	struct gotd_imsgev *iev = arg;
1377 	struct imsgbuf *ibuf = &iev->ibuf;
1378 	struct gotd_session_client *client = &gotd_session_client;
1379 	ssize_t n;
1380 	int shut = 0;
1381 	struct imsg imsg;
1382 
1383 	if (event & EV_READ) {
1384 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1385 			fatal("imsg_read error");
1386 		if (n == 0) {
1387 			/* Connection closed. */
1388 			shut = 1;
1389 			goto done;
1390 		}
1391 	}
1392 
1393 	if (event & EV_WRITE) {
1394 		n = msgbuf_write(&ibuf->w);
1395 		if (n == -1 && errno != EAGAIN)
1396 			fatal("msgbuf_write");
1397 		if (n == 0) {
1398 			/* Connection closed. */
1399 			shut = 1;
1400 			goto done;
1401 		}
1402 	}
1403 
1404 	for (;;) {
1405 		const struct got_error *err = NULL;
1406 		uint32_t client_id = 0;
1407 		int do_disconnect = 0, do_list_refs = 0;
1408 
1409 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1410 			fatal("%s: imsg_get error", __func__);
1411 		if (n == 0)	/* No more messages. */
1412 			break;
1413 
1414 		switch (imsg.hdr.type) {
1415 		case GOTD_IMSG_ERROR:
1416 			do_disconnect = 1;
1417 			err = gotd_imsg_recv_error(&client_id, &imsg);
1418 			break;
1419 		case GOTD_IMSG_CONNECT:
1420 			err = recv_connect(&imsg);
1421 			break;
1422 		case GOTD_IMSG_DISCONNECT:
1423 			do_disconnect = 1;
1424 			break;
1425 		case GOTD_IMSG_CONNECT_REPO_CHILD:
1426 			err = recv_repo_child(&imsg);
1427 			if (err)
1428 				break;
1429 			do_list_refs = 1;
1430 			break;
1431 		default:
1432 			log_debug("unexpected imsg %d", imsg.hdr.type);
1433 			break;
1434 		}
1435 		imsg_free(&imsg);
1436 
1437 		if (do_disconnect) {
1438 			if (err)
1439 				disconnect_on_error(client, err);
1440 			else
1441 				disconnect(client);
1442 		} else if (do_list_refs)
1443 			err = list_refs_request();
1444 
1445 		if (err)
1446 			log_warnx("uid %d: %s", client->euid, err->msg);
1447 	}
1448 done:
1449 	if (!shut) {
1450 		gotd_imsg_event_add(iev);
1451 	} else {
1452 		/* This pipe is dead. Remove its event handler */
1453 		event_del(&iev->ev);
1454 		event_loopexit(NULL);
1455 	}
1456 }
1457 
1458 void
1459 session_main(const char *title, const char *repo_path,
1460     int *pack_fds, int *temp_fds, struct timeval *request_timeout,
1461     enum gotd_procid proc_id)
1462 {
1463 	const struct got_error *err = NULL;
1464 	struct event evsigint, evsigterm, evsighup, evsigusr1;
1465 
1466 	gotd_session.title = title;
1467 	gotd_session.pid = getpid();
1468 	gotd_session.pack_fds = pack_fds;
1469 	gotd_session.temp_fds = temp_fds;
1470 	memcpy(&gotd_session.request_timeout, request_timeout,
1471 	    sizeof(gotd_session.request_timeout));
1472 	gotd_session.proc_id = proc_id;
1473 
1474 	err = got_repo_open(&gotd_session.repo, repo_path, NULL, pack_fds);
1475 	if (err)
1476 		goto done;
1477 	if (!got_repo_is_bare(gotd_session.repo)) {
1478 		err = got_error_msg(GOT_ERR_NOT_GIT_REPO,
1479 		    "bare git repository required");
1480 		goto done;
1481 	}
1482 
1483 	got_repo_temp_fds_set(gotd_session.repo, temp_fds);
1484 
1485 	signal_set(&evsigint, SIGINT, gotd_session_sighdlr, NULL);
1486 	signal_set(&evsigterm, SIGTERM, gotd_session_sighdlr, NULL);
1487 	signal_set(&evsighup, SIGHUP, gotd_session_sighdlr, NULL);
1488 	signal_set(&evsigusr1, SIGUSR1, gotd_session_sighdlr, NULL);
1489 	signal(SIGPIPE, SIG_IGN);
1490 
1491 	signal_add(&evsigint, NULL);
1492 	signal_add(&evsigterm, NULL);
1493 	signal_add(&evsighup, NULL);
1494 	signal_add(&evsigusr1, NULL);
1495 
1496 	gotd_session_client.state = GOTD_STATE_EXPECT_LIST_REFS;
1497 	gotd_session_client.fd = -1;
1498 	gotd_session_client.nref_updates = -1;
1499 	gotd_session_client.delta_cache_fd = -1;
1500 	gotd_session_client.accept_flush_pkt = 1;
1501 
1502 	imsg_init(&gotd_session.parent_iev.ibuf, GOTD_FILENO_MSG_PIPE);
1503 	gotd_session.parent_iev.handler = session_dispatch;
1504 	gotd_session.parent_iev.events = EV_READ;
1505 	gotd_session.parent_iev.handler_arg = NULL;
1506 	event_set(&gotd_session.parent_iev.ev, gotd_session.parent_iev.ibuf.fd,
1507 	    EV_READ, session_dispatch, &gotd_session.parent_iev);
1508 	if (gotd_imsg_compose_event(&gotd_session.parent_iev,
1509 	    GOTD_IMSG_CLIENT_SESSION_READY, gotd_session.proc_id,
1510 	    -1, NULL, 0) == -1) {
1511 		err = got_error_from_errno("imsg compose CLIENT_SESSION_READY");
1512 		goto done;
1513 	}
1514 
1515 	event_dispatch();
1516 done:
1517 	if (err)
1518 		log_warnx("%s: %s", title, err->msg);
1519 	gotd_session_shutdown();
1520 }
1521 
1522 void
1523 gotd_session_shutdown(void)
1524 {
1525 	log_debug("shutting down");
1526 	if (gotd_session.repo)
1527 		got_repo_close(gotd_session.repo);
1528 	got_repo_pack_fds_close(gotd_session.pack_fds);
1529 	got_repo_temp_fds_close(gotd_session.temp_fds);
1530 	exit(0);
1531 }