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Date:: Fri Mar 22 10:17:03 2024 UTC
Message:: display process title in syslog when a gotd child process exits
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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_write.h"
55 
56 struct gotd_session_notif {
57 	STAILQ_ENTRY(gotd_session_notif) entry;
58 	int fd;
59 	enum gotd_notification_action action;
60 	char *refname;
61 	struct got_object_id old_id;
62 	struct got_object_id new_id;
63 };
64 STAILQ_HEAD(gotd_session_notifications, gotd_session_notif) notifications;
65 
66 enum gotd_session_write_state {
67 	GOTD_STATE_EXPECT_LIST_REFS,
68 	GOTD_STATE_EXPECT_CAPABILITIES,
69 	GOTD_STATE_EXPECT_REF_UPDATE,
70 	GOTD_STATE_EXPECT_MORE_REF_UPDATES,
71 	GOTD_STATE_EXPECT_PACKFILE,
72 	GOTD_STATE_NOTIFY,
73 };
74 
75 static struct gotd_session_write {
76 	pid_t pid;
77 	const char *title;
78 	struct got_repository *repo;
79 	struct gotd_repo *repo_cfg;
80 	int *pack_fds;
81 	int *temp_fds;
82 	struct gotd_imsgev parent_iev;
83 	struct gotd_imsgev notifier_iev;
84 	struct timeval request_timeout;
85 	enum gotd_session_write_state state;
86 	struct gotd_imsgev repo_child_iev;
87 } gotd_session;
88 
89 static struct gotd_session_client {
90 	struct gotd_client_capability	*capabilities;
91 	size_t				 ncapa_alloc;
92 	size_t				 ncapabilities;
93 	uint32_t			 id;
94 	int				 fd;
95 	int				 delta_cache_fd;
96 	struct gotd_imsgev		 iev;
97 	struct event			 tmo;
98 	uid_t				 euid;
99 	gid_t				 egid;
100 	char				*username;
101 	char				*packfile_path;
102 	char				*packidx_path;
103 	int				 nref_updates;
104 	int				 accept_flush_pkt;
105 	int				 flush_disconnect;
106 } gotd_session_client;
107 
108 static void session_write_shutdown(void);
109 
110 static void
111 disconnect(struct gotd_session_client *client)
112 {
113 	log_debug("uid %d: disconnecting", client->euid);
114 
115 	if (gotd_imsg_compose_event(&gotd_session.parent_iev,
116 	    GOTD_IMSG_DISCONNECT, PROC_SESSION_WRITE, -1, NULL, 0) == -1)
117 		log_warn("imsg compose DISCONNECT");
118 
119 	imsg_clear(&gotd_session.repo_child_iev.ibuf);
120 	event_del(&gotd_session.repo_child_iev.ev);
121 	evtimer_del(&client->tmo);
122 	close(client->fd);
123 	if (client->delta_cache_fd != -1)
124 		close(client->delta_cache_fd);
125 	if (client->packfile_path) {
126 		if (unlink(client->packfile_path) == -1 && errno != ENOENT)
127 			log_warn("unlink %s: ", client->packfile_path);
128 		free(client->packfile_path);
129 	}
130 	if (client->packidx_path) {
131 		if (unlink(client->packidx_path) == -1 && errno != ENOENT)
132 			log_warn("unlink %s: ", client->packidx_path);
133 		free(client->packidx_path);
134 	}
135 	free(client->capabilities);
136 
137 	session_write_shutdown();
138 }
139 
140 static void
141 disconnect_on_error(struct gotd_session_client *client,
142     const struct got_error *err)
143 {
144 	struct imsgbuf ibuf;
145 
146 	if (err->code != GOT_ERR_EOF) {
147 		log_warnx("uid %d: %s", client->euid, err->msg);
148 		imsg_init(&ibuf, client->fd);
149 		gotd_imsg_send_error(&ibuf, 0, PROC_SESSION_WRITE, err);
150 		imsg_clear(&ibuf);
151 	}
152 
153 	disconnect(client);
154 }
155 
156 static void
157 gotd_request_timeout(int fd, short events, void *arg)
158 {
159 	struct gotd_session_client *client = arg;
160 
161 	log_debug("disconnecting uid %d due to timeout", client->euid);
162 	disconnect(client);
163 }
164 
165 static void
166 session_write_sighdlr(int sig, short event, void *arg)
167 {
168 	/*
169 	 * Normal signal handler rules don't apply because libevent
170 	 * decouples for us.
171 	 */
172 
173 	switch (sig) {
174 	case SIGHUP:
175 		log_info("%s: ignoring SIGHUP", __func__);
176 		break;
177 	case SIGUSR1:
178 		log_info("%s: ignoring SIGUSR1", __func__);
179 		break;
180 	case SIGTERM:
181 	case SIGINT:
182 		session_write_shutdown();
183 		/* NOTREACHED */
184 		break;
185 	default:
186 		fatalx("unexpected signal");
187 	}
188 }
189 
190 static const struct got_error *
191 recv_packfile_install(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 	return NULL;
204 }
205 
206 static const struct got_error *
207 recv_ref_updates_start(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 	return NULL;
220 }
221 
222 static const struct got_error *
223 recv_ref_update(struct imsg *imsg)
224 {
225 	struct gotd_imsg_ref_update iref;
226 	size_t datalen;
227 
228 	log_debug("ref-update received");
229 
230 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
231 	if (datalen < sizeof(iref))
232 		return got_error(GOT_ERR_PRIVSEP_LEN);
233 	memcpy(&iref, imsg->data, sizeof(iref));
234 
235 	return NULL;
236 }
237 
238 static const struct got_error *
239 send_ref_update_ok(struct gotd_session_client *client,
240     struct gotd_imsg_ref_update *iref, const char *refname)
241 {
242 	struct gotd_imsg_ref_update_ok iok;
243 	struct gotd_imsgev *iev = &client->iev;
244 	struct ibuf *wbuf;
245 	size_t len;
246 
247 	memset(&iok, 0, sizeof(iok));
248 	memcpy(iok.old_id, iref->old_id, SHA1_DIGEST_LENGTH);
249 	memcpy(iok.new_id, iref->new_id, SHA1_DIGEST_LENGTH);
250 	iok.name_len = strlen(refname);
251 
252 	len = sizeof(iok) + iok.name_len;
253 	wbuf = imsg_create(&iev->ibuf, GOTD_IMSG_REF_UPDATE_OK,
254 	    PROC_SESSION_WRITE, gotd_session.pid, len);
255 	if (wbuf == NULL)
256 		return got_error_from_errno("imsg_create REF_UPDATE_OK");
257 
258 	if (imsg_add(wbuf, &iok, sizeof(iok)) == -1)
259 		return got_error_from_errno("imsg_add REF_UPDATE_OK");
260 	if (imsg_add(wbuf, refname, iok.name_len) == -1)
261 		return got_error_from_errno("imsg_add REF_UPDATE_OK");
262 
263 	imsg_close(&iev->ibuf, wbuf);
264 	gotd_imsg_event_add(iev);
265 	return NULL;
266 }
267 
268 static void
269 send_refs_updated(struct gotd_session_client *client)
270 {
271 	if (gotd_imsg_compose_event(&client->iev, GOTD_IMSG_REFS_UPDATED,
272 	    PROC_SESSION_WRITE, -1, NULL, 0) == -1)
273 		log_warn("imsg compose REFS_UPDATED");
274 }
275 
276 static const struct got_error *
277 send_ref_update_ng(struct gotd_session_client *client,
278     struct gotd_imsg_ref_update *iref, const char *refname,
279     const char *reason)
280 {
281 	const struct got_error *ng_err;
282 	struct gotd_imsg_ref_update_ng ing;
283 	struct gotd_imsgev *iev = &client->iev;
284 	struct ibuf *wbuf;
285 	size_t len;
286 
287 	memset(&ing, 0, sizeof(ing));
288 	memcpy(ing.old_id, iref->old_id, SHA1_DIGEST_LENGTH);
289 	memcpy(ing.new_id, iref->new_id, SHA1_DIGEST_LENGTH);
290 	ing.name_len = strlen(refname);
291 
292 	ng_err = got_error_fmt(GOT_ERR_REF_BUSY, "%s", reason);
293 	ing.reason_len = strlen(ng_err->msg);
294 
295 	len = sizeof(ing) + ing.name_len + ing.reason_len;
296 	wbuf = imsg_create(&iev->ibuf, GOTD_IMSG_REF_UPDATE_NG,
297 	    PROC_SESSION_WRITE, gotd_session.pid, len);
298 	if (wbuf == NULL)
299 		return got_error_from_errno("imsg_create REF_UPDATE_NG");
300 
301 	if (imsg_add(wbuf, &ing, sizeof(ing)) == -1)
302 		return got_error_from_errno("imsg_add REF_UPDATE_NG");
303 	if (imsg_add(wbuf, refname, ing.name_len) == -1)
304 		return got_error_from_errno("imsg_add REF_UPDATE_NG");
305 	if (imsg_add(wbuf, ng_err->msg, ing.reason_len) == -1)
306 		return got_error_from_errno("imsg_add REF_UPDATE_NG");
307 
308 	imsg_close(&iev->ibuf, wbuf);
309 	gotd_imsg_event_add(iev);
310 	return NULL;
311 }
312 
313 static const struct got_error *
314 install_pack(struct gotd_session_client *client, const char *repo_path,
315     struct imsg *imsg)
316 {
317 	const struct got_error *err = NULL;
318 	struct gotd_imsg_packfile_install inst;
319 	char hex[SHA1_DIGEST_STRING_LENGTH];
320 	size_t datalen;
321 	char *packfile_path = NULL, *packidx_path = NULL;
322 
323 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
324 	if (datalen != sizeof(inst))
325 		return got_error(GOT_ERR_PRIVSEP_LEN);
326 	memcpy(&inst, imsg->data, sizeof(inst));
327 
328 	if (client->packfile_path == NULL)
329 		return got_error_msg(GOT_ERR_BAD_REQUEST,
330 		    "client has no pack file");
331 	if (client->packidx_path == NULL)
332 		return got_error_msg(GOT_ERR_BAD_REQUEST,
333 		    "client has no pack file index");
334 
335 	if (got_sha1_digest_to_str(inst.pack_sha1, hex, sizeof(hex)) == NULL)
336 		return got_error_msg(GOT_ERR_NO_SPACE,
337 		    "could not convert pack file SHA1 to hex");
338 
339 	if (asprintf(&packfile_path, "/%s/%s/pack-%s.pack",
340 	    repo_path, GOT_OBJECTS_PACK_DIR, hex) == -1) {
341 		err = got_error_from_errno("asprintf");
342 		goto done;
343 	}
344 
345 	if (asprintf(&packidx_path, "/%s/%s/pack-%s.idx",
346 	    repo_path, GOT_OBJECTS_PACK_DIR, hex) == -1) {
347 		err = got_error_from_errno("asprintf");
348 		goto done;
349 	}
350 
351 	if (rename(client->packfile_path, packfile_path) == -1) {
352 		err = got_error_from_errno3("rename", client->packfile_path,
353 		    packfile_path);
354 		goto done;
355 	}
356 
357 	free(client->packfile_path);
358 	client->packfile_path = NULL;
359 
360 	if (rename(client->packidx_path, packidx_path) == -1) {
361 		err = got_error_from_errno3("rename", client->packidx_path,
362 		    packidx_path);
363 		goto done;
364 	}
365 
366 	/* Ensure we re-read the pack index list upon next access. */
367 	gotd_session.repo->pack_path_mtime.tv_sec = 0;
368 	gotd_session.repo->pack_path_mtime.tv_nsec = 0;
369 
370 	free(client->packidx_path);
371 	client->packidx_path = NULL;
372 done:
373 	free(packfile_path);
374 	free(packidx_path);
375 	return err;
376 }
377 
378 static const struct got_error *
379 begin_ref_updates(struct gotd_session_client *client, struct imsg *imsg)
380 {
381 	struct gotd_imsg_ref_updates_start istart;
382 	size_t datalen;
383 
384 	if (client->nref_updates != -1)
385 		return got_error(GOT_ERR_PRIVSEP_MSG);
386 
387 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
388 	if (datalen != sizeof(istart))
389 		return got_error(GOT_ERR_PRIVSEP_LEN);
390 	memcpy(&istart, imsg->data, sizeof(istart));
391 
392 	if (istart.nref_updates <= 0)
393 		return got_error(GOT_ERR_PRIVSEP_MSG);
394 
395 	client->nref_updates = istart.nref_updates;
396 	return NULL;
397 }
398 
399 static const struct got_error *
400 validate_namespace(const char *namespace)
401 {
402 	size_t len = strlen(namespace);
403 
404 	if (len < 5 || strncmp("refs/", namespace, 5) != 0 ||
405 	    namespace[len - 1] != '/') {
406 		return got_error_fmt(GOT_ERR_BAD_REF_NAME,
407 		    "reference namespace '%s'", namespace);
408 	}
409 
410 	return NULL;
411 }
412 
413 static const struct got_error *
414 queue_notification(struct got_object_id *old_id, struct got_object_id *new_id,
415     struct got_repository *repo, struct got_reference *ref)
416 {
417 	const struct got_error *err = NULL;
418 	struct gotd_repo *repo_cfg = gotd_session.repo_cfg;
419 	struct gotd_imsgev *iev = &gotd_session.repo_child_iev;
420 	struct got_pathlist_entry *pe;
421 	struct gotd_session_notif *notif;
422 
423 	if (iev->ibuf.fd == -1 ||
424 	    STAILQ_EMPTY(&repo_cfg->notification_targets))
425 		return NULL; /* notifications unused */
426 
427 	TAILQ_FOREACH(pe, &repo_cfg->notification_refs, entry) {
428 		const char *refname = pe->path;
429 		if (strcmp(got_ref_get_name(ref), refname) == 0)
430 			break;
431 	}
432 	if (pe == NULL) {
433 		TAILQ_FOREACH(pe, &repo_cfg->notification_ref_namespaces,
434 		    entry) {
435 			const char *namespace = pe->path;
436 
437 			err = validate_namespace(namespace);
438 			if (err)
439 				return err;
440 			if (strncmp(namespace, got_ref_get_name(ref),
441 			    strlen(namespace)) == 0)
442 				break;
443 		}
444 	}
445 
446 	/*
447 	 * If a branch or a reference namespace was specified in the
448 	 * configuration file then only send notifications if a match
449 	 * was found.
450 	 */
451 	if (pe == NULL && (!TAILQ_EMPTY(&repo_cfg->notification_refs) ||
452 	    !TAILQ_EMPTY(&repo_cfg->notification_ref_namespaces)))
453 		return NULL;
454 
455 	notif = calloc(1, sizeof(*notif));
456 	if (notif == NULL)
457 		return got_error_from_errno("calloc");
458 
459 	notif->fd = -1;
460 
461 	if (old_id == NULL)
462 		notif->action = GOTD_NOTIF_ACTION_CREATED;
463 	else if (new_id == NULL)
464 		notif->action = GOTD_NOTIF_ACTION_REMOVED;
465 	else
466 		notif->action = GOTD_NOTIF_ACTION_CHANGED;
467 
468 	if (old_id != NULL)
469 		memcpy(&notif->old_id, old_id, sizeof(notif->old_id));
470 	if (new_id != NULL)
471 		memcpy(&notif->new_id, new_id, sizeof(notif->new_id));
472 
473 	notif->refname = strdup(got_ref_get_name(ref));
474 	if (notif->refname == NULL) {
475 		err = got_error_from_errno("strdup");
476 		goto done;
477 	}
478 
479 	STAILQ_INSERT_TAIL(&notifications, notif, entry);
480 done:
481 	if (err && notif) {
482 		free(notif->refname);
483 		free(notif);
484 	}
485 	return err;
486 }
487 
488 /* Forward notification content to the NOTIFY process. */
489 static const struct got_error *
490 forward_notification(struct gotd_session_client *client, struct imsg *imsg)
491 {
492 	const struct got_error *err = NULL;
493 	struct gotd_imsgev *iev = &gotd_session.notifier_iev;
494 	struct gotd_session_notif *notif;
495 	struct gotd_imsg_notification_content icontent;
496 	char *refname = NULL;
497 	size_t datalen;
498 	struct gotd_imsg_notify inotify;
499 	const char *action;
500 
501 	memset(&inotify, 0, sizeof(inotify));
502 
503 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
504 	if (datalen < sizeof(icontent))
505 		return got_error(GOT_ERR_PRIVSEP_LEN);
506 	memcpy(&icontent, imsg->data, sizeof(icontent));
507 	if (datalen != sizeof(icontent) + icontent.refname_len)
508 		return got_error(GOT_ERR_PRIVSEP_LEN);
509 	refname = strndup(imsg->data + sizeof(icontent), icontent.refname_len);
510 	if (refname == NULL)
511 		return got_error_from_errno("strndup");
512 
513 	notif = STAILQ_FIRST(&notifications);
514 	if (notif == NULL)
515 		return got_error(GOT_ERR_PRIVSEP_MSG);
516 
517 	STAILQ_REMOVE(&notifications, notif, gotd_session_notif, entry);
518 
519 	if (notif->action != icontent.action || notif->fd == -1 ||
520 	    strcmp(notif->refname, refname) != 0) {
521 		err = got_error(GOT_ERR_PRIVSEP_MSG);
522 		goto done;
523 	}
524 	if (notif->action == GOTD_NOTIF_ACTION_CREATED) {
525 		if (memcmp(notif->new_id.sha1, icontent.new_id,
526 		    SHA1_DIGEST_LENGTH) != 0) {
527 			err = got_error_msg(GOT_ERR_PRIVSEP_MSG,
528 			    "received notification content for unknown event");
529 			goto done;
530 		}
531 	} else if (notif->action == GOTD_NOTIF_ACTION_REMOVED) {
532 		if (memcmp(notif->old_id.sha1, icontent.old_id,
533 		    SHA1_DIGEST_LENGTH) != 0) {
534 			err = got_error_msg(GOT_ERR_PRIVSEP_MSG,
535 			    "received notification content for unknown event");
536 			goto done;
537 		}
538 	} else if (memcmp(notif->old_id.sha1, icontent.old_id,
539 	    SHA1_DIGEST_LENGTH) != 0 ||
540 	    memcmp(notif->new_id.sha1, icontent.new_id,
541 	    SHA1_DIGEST_LENGTH) != 0) {
542 		err = got_error_msg(GOT_ERR_PRIVSEP_MSG,
543 		    "received notification content for unknown event");
544 		goto done;
545 	}
546 
547 	switch (notif->action) {
548 	case GOTD_NOTIF_ACTION_CREATED:
549 		action = "created";
550 		break;
551 	case GOTD_NOTIF_ACTION_REMOVED:
552 		action = "removed";
553 		break;
554 	case GOTD_NOTIF_ACTION_CHANGED:
555 		action = "changed";
556 		break;
557 	default:
558 		err = got_error(GOT_ERR_PRIVSEP_MSG);
559 		goto done;
560 	}
561 
562 	strlcpy(inotify.repo_name, gotd_session.repo_cfg->name,
563 	    sizeof(inotify.repo_name));
564 
565 	snprintf(inotify.subject_line, sizeof(inotify.subject_line),
566 	    "%s: %s %s %s", gotd_session.repo_cfg->name,
567 	    client->username, action, notif->refname);
568 
569 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_NOTIFY,
570 	    PROC_SESSION_WRITE, notif->fd, &inotify, sizeof(inotify))
571 	    == -1) {
572 		err = got_error_from_errno("imsg compose NOTIFY");
573 		goto done;
574 	}
575 	notif->fd = -1;
576 done:
577 	if (notif->fd != -1)
578 		close(notif->fd);
579 	free(notif);
580 	free(refname);
581 	return err;
582 }
583 
584 /* Request notification content from REPO_WRITE process. */
585 static const struct got_error *
586 request_notification(struct gotd_session_notif *notif)
587 {
588 	const struct got_error *err = NULL;
589 	struct gotd_imsgev *iev = &gotd_session.repo_child_iev;
590 	struct gotd_imsg_notification_content icontent;
591 	struct ibuf *wbuf;
592 	size_t len;
593 	int fd;
594 
595 	fd = got_opentempfd();
596 	if (fd == -1)
597 		return got_error_from_errno("got_opentemp");
598 
599 	memset(&icontent, 0, sizeof(icontent));
600 
601 	icontent.action = notif->action;
602 	memcpy(&icontent.old_id, &notif->old_id, sizeof(notif->old_id));
603 	memcpy(&icontent.new_id, &notif->new_id, sizeof(notif->new_id));
604 	icontent.refname_len = strlen(notif->refname);
605 
606 	len = sizeof(icontent) + icontent.refname_len;
607 	wbuf = imsg_create(&iev->ibuf, GOTD_IMSG_NOTIFY,
608 	    PROC_SESSION_WRITE, gotd_session.pid, len);
609 	if (wbuf == NULL) {
610 		err = got_error_from_errno("imsg_create NOTIFY");
611 		goto done;
612 	}
613 	if (imsg_add(wbuf, &icontent, sizeof(icontent)) == -1) {
614 		err = got_error_from_errno("imsg_add NOTIFY");
615 		goto done;
616 	}
617 	if (imsg_add(wbuf, notif->refname, icontent.refname_len) == -1) {
618 		err = got_error_from_errno("imsg_add NOTIFY");
619 		goto done;
620 	}
621 
622 	notif->fd = dup(fd);
623 	if (notif->fd == -1) {
624 		err = got_error_from_errno("dup");
625 		goto done;
626 	}
627 
628 	ibuf_fd_set(wbuf, fd);
629 	fd = -1;
630 
631 	imsg_close(&iev->ibuf, wbuf);
632 	gotd_imsg_event_add(iev);
633 done:
634 	if (err && fd != -1)
635 		close(fd);
636 	return err;
637 }
638 
639 static const struct got_error *
640 update_ref(int *shut, struct gotd_session_client *client,
641     const char *repo_path, struct imsg *imsg)
642 {
643 	const struct got_error *err = NULL;
644 	struct got_repository *repo = gotd_session.repo;
645 	struct got_reference *ref = NULL;
646 	struct gotd_imsg_ref_update iref;
647 	struct got_object_id old_id, new_id;
648 	struct gotd_session_notif *notif;
649 	struct got_object_id *id = NULL;
650 	char *refname = NULL;
651 	size_t datalen;
652 	int locked = 0;
653 	char hex1[SHA1_DIGEST_STRING_LENGTH];
654 	char hex2[SHA1_DIGEST_STRING_LENGTH];
655 
656 	log_debug("update-ref from uid %d", client->euid);
657 
658 	if (client->nref_updates <= 0)
659 		return got_error(GOT_ERR_PRIVSEP_MSG);
660 
661 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
662 	if (datalen < sizeof(iref))
663 		return got_error(GOT_ERR_PRIVSEP_LEN);
664 	memcpy(&iref, imsg->data, sizeof(iref));
665 	if (datalen != sizeof(iref) + iref.name_len)
666 		return got_error(GOT_ERR_PRIVSEP_LEN);
667 	refname = strndup(imsg->data + sizeof(iref), iref.name_len);
668 	if (refname == NULL)
669 		return got_error_from_errno("strndup");
670 
671 	log_debug("updating ref %s for uid %d", refname, client->euid);
672 
673 	memcpy(old_id.sha1, iref.old_id, SHA1_DIGEST_LENGTH);
674 	memcpy(new_id.sha1, iref.new_id, SHA1_DIGEST_LENGTH);
675 	err = got_repo_find_object_id(iref.delete_ref ? &old_id : &new_id,
676 	    repo);
677 	if (err)
678 		goto done;
679 
680 	if (iref.ref_is_new) {
681 		err = got_ref_open(&ref, repo, refname, 0);
682 		if (err) {
683 			if (err->code != GOT_ERR_NOT_REF)
684 				goto done;
685 			err = got_ref_alloc(&ref, refname, &new_id);
686 			if (err)
687 				goto done;
688 			err = got_ref_write(ref, repo); /* will lock/unlock */
689 			if (err)
690 				goto done;
691 			err = queue_notification(NULL, &new_id, repo, ref);
692 			if (err)
693 				goto done;
694 		} else {
695 			err = got_ref_resolve(&id, repo, ref);
696 			if (err)
697 				goto done;
698 			got_object_id_hex(&new_id, hex1, sizeof(hex1));
699 			got_object_id_hex(id, hex2, sizeof(hex2));
700 			err = got_error_fmt(GOT_ERR_REF_BUSY,
701 			    "Addition %s: %s failed; %s: %s has been "
702 			    "created by someone else while transaction "
703 			    "was in progress",
704 			    got_ref_get_name(ref), hex1,
705 			    got_ref_get_name(ref), hex2);
706 			goto done;
707 		}
708 	} else if (iref.delete_ref) {
709 		err = got_ref_open(&ref, repo, refname, 1 /* lock */);
710 		if (err)
711 			goto done;
712 		locked = 1;
713 
714 		err = got_ref_resolve(&id, repo, ref);
715 		if (err)
716 			goto done;
717 
718 		if (got_object_id_cmp(id, &old_id) != 0) {
719 			got_object_id_hex(&old_id, hex1, sizeof(hex1));
720 			got_object_id_hex(id, hex2, sizeof(hex2));
721 			err = got_error_fmt(GOT_ERR_REF_BUSY,
722 			    "Deletion %s: %s failed; %s: %s has been "
723 			    "created by someone else while transaction "
724 			    "was in progress",
725 			    got_ref_get_name(ref), hex1,
726 			    got_ref_get_name(ref), hex2);
727 			goto done;
728 		}
729 
730 		err = got_ref_delete(ref, repo);
731 		if (err)
732 			goto done;
733 		err = queue_notification(&old_id, NULL, repo, ref);
734 		if (err)
735 			goto done;
736 		free(id);
737 		id = NULL;
738 	} else {
739 		err = got_ref_open(&ref, repo, refname, 1 /* lock */);
740 		if (err)
741 			goto done;
742 		locked = 1;
743 
744 		err = got_ref_resolve(&id, repo, ref);
745 		if (err)
746 			goto done;
747 
748 		if (got_object_id_cmp(id, &old_id) != 0) {
749 			got_object_id_hex(&old_id, hex1, sizeof(hex1));
750 			got_object_id_hex(id, hex2, sizeof(hex2));
751 			err = got_error_fmt(GOT_ERR_REF_BUSY,
752 			    "Update %s: %s failed; %s: %s has been "
753 			    "created by someone else while transaction "
754 			    "was in progress",
755 			    got_ref_get_name(ref), hex1,
756 			    got_ref_get_name(ref), hex2);
757 			goto done;
758 		}
759 
760 		if (got_object_id_cmp(&new_id, &old_id) != 0) {
761 			err = got_ref_change_ref(ref, &new_id);
762 			if (err)
763 				goto done;
764 			err = got_ref_write(ref, repo);
765 			if (err)
766 				goto done;
767 			err = queue_notification(&old_id, &new_id, repo, ref);
768 			if (err)
769 				goto done;
770 		}
771 
772 		free(id);
773 		id = NULL;
774 	}
775 done:
776 	if (err) {
777 		if (err->code == GOT_ERR_LOCKFILE_TIMEOUT) {
778 			err = got_error_fmt(GOT_ERR_LOCKFILE_TIMEOUT,
779 			    "could not acquire exclusive file lock for %s",
780 			    refname);
781 		}
782 		send_ref_update_ng(client, &iref, refname, err->msg);
783 	} else
784 		send_ref_update_ok(client, &iref, refname);
785 
786 	if (client->nref_updates > 0) {
787 		client->nref_updates--;
788 		if (client->nref_updates == 0) {
789 			send_refs_updated(client);
790 			notif = STAILQ_FIRST(&notifications);
791 			if (notif) {
792 				gotd_session.state = GOTD_STATE_NOTIFY;
793 				err = request_notification(notif);
794 				if (err) {
795 					log_warn("could not send notification: "
796 					    "%s", err->msg);
797 					client->flush_disconnect = 1;
798 				}
799 			} else
800 				client->flush_disconnect = 1;
801 		}
802 
803 	}
804 	if (locked) {
805 		const struct got_error *unlock_err;
806 		unlock_err = got_ref_unlock(ref);
807 		if (unlock_err && err == NULL)
808 			err = unlock_err;
809 	}
810 	if (ref)
811 		got_ref_close(ref);
812 	free(refname);
813 	free(id);
814 	return err;
815 }
816 
817 static const struct got_error *
818 recv_notification_content(struct imsg *imsg)
819 {
820 	struct gotd_imsg_notification_content inotif;
821 	size_t datalen;
822 
823 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
824 	if (datalen < sizeof(inotif))
825 		return got_error(GOT_ERR_PRIVSEP_LEN);
826 	memcpy(&inotif, imsg->data, sizeof(inotif));
827 
828 	return NULL;
829 }
830 
831 static void
832 session_dispatch_repo_child(int fd, short event, void *arg)
833 {
834 	struct gotd_imsgev *iev = arg;
835 	struct imsgbuf *ibuf = &iev->ibuf;
836 	struct gotd_session_client *client = &gotd_session_client;
837 	ssize_t n;
838 	int shut = 0;
839 	struct imsg imsg;
840 
841 	if (event & EV_READ) {
842 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
843 			fatal("imsg_read error");
844 		if (n == 0) {
845 			/* Connection closed. */
846 			shut = 1;
847 			goto done;
848 		}
849 	}
850 
851 	if (event & EV_WRITE) {
852 		n = msgbuf_write(&ibuf->w);
853 		if (n == -1 && errno != EAGAIN)
854 			fatal("msgbuf_write");
855 		if (n == 0) {
856 			/* Connection closed. */
857 			shut = 1;
858 			goto done;
859 		}
860 	}
861 
862 	for (;;) {
863 		const struct got_error *err = NULL;
864 		uint32_t client_id = 0;
865 		int do_disconnect = 0;
866 		int do_ref_updates = 0, do_ref_update = 0;
867 		int do_packfile_install = 0, do_notify = 0;
868 
869 		if ((n = imsg_get(ibuf, &imsg)) == -1)
870 			fatal("%s: imsg_get error", __func__);
871 		if (n == 0)	/* No more messages. */
872 			break;
873 
874 		switch (imsg.hdr.type) {
875 		case GOTD_IMSG_ERROR:
876 			do_disconnect = 1;
877 			err = gotd_imsg_recv_error(&client_id, &imsg);
878 			break;
879 		case GOTD_IMSG_PACKFILE_INSTALL:
880 			err = recv_packfile_install(&imsg);
881 			if (err == NULL)
882 				do_packfile_install = 1;
883 			break;
884 		case GOTD_IMSG_REF_UPDATES_START:
885 			err = recv_ref_updates_start(&imsg);
886 			if (err == NULL)
887 				do_ref_updates = 1;
888 			break;
889 		case GOTD_IMSG_REF_UPDATE:
890 			err = recv_ref_update(&imsg);
891 			if (err == NULL)
892 				do_ref_update = 1;
893 			break;
894 		case GOTD_IMSG_NOTIFY:
895 			err = recv_notification_content(&imsg);
896 			if (err == NULL)
897 				do_notify = 1;
898 			break;
899 		default:
900 			log_debug("unexpected imsg %d", imsg.hdr.type);
901 			break;
902 		}
903 
904 		if (do_disconnect) {
905 			if (err)
906 				disconnect_on_error(client, err);
907 			else
908 				disconnect(client);
909 		} else {
910 			struct gotd_session_notif *notif;
911 
912 			if (do_packfile_install)
913 				err = install_pack(client,
914 				    gotd_session.repo->path, &imsg);
915 			else if (do_ref_updates)
916 				err = begin_ref_updates(client, &imsg);
917 			else if (do_ref_update)
918 				err = update_ref(&shut, client,
919 				    gotd_session.repo->path, &imsg);
920 			else if (do_notify)
921 				err = forward_notification(client, &imsg);
922 			if (err)
923 				log_warnx("uid %d: %s", client->euid, err->msg);
924 
925 			notif = STAILQ_FIRST(&notifications);
926 			if (notif && do_notify) {
927 				/* Request content for next notification. */
928 				err = request_notification(notif);
929 				if (err) {
930 					log_warn("could not send notification: "
931 					    "%s", err->msg);
932 					shut = 1;
933 				}
934 			}
935 		}
936 		imsg_free(&imsg);
937 	}
938 done:
939 	if (!shut) {
940 		gotd_imsg_event_add(iev);
941 	} else {
942 		/* This pipe is dead. Remove its event handler */
943 		event_del(&iev->ev);
944 		event_loopexit(NULL);
945 	}
946 }
947 
948 static const struct got_error *
949 recv_capabilities(struct gotd_session_client *client, struct imsg *imsg)
950 {
951 	struct gotd_imsg_capabilities icapas;
952 	size_t datalen;
953 
954 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
955 	if (datalen != sizeof(icapas))
956 		return got_error(GOT_ERR_PRIVSEP_LEN);
957 	memcpy(&icapas, imsg->data, sizeof(icapas));
958 
959 	client->ncapa_alloc = icapas.ncapabilities;
960 	client->capabilities = calloc(client->ncapa_alloc,
961 	    sizeof(*client->capabilities));
962 	if (client->capabilities == NULL) {
963 		client->ncapa_alloc = 0;
964 		return got_error_from_errno("calloc");
965 	}
966 
967 	log_debug("expecting %zu capabilities from uid %d",
968 	    client->ncapa_alloc, client->euid);
969 	return NULL;
970 }
971 
972 static const struct got_error *
973 recv_capability(struct gotd_session_client *client, struct imsg *imsg)
974 {
975 	struct gotd_imsg_capability icapa;
976 	struct gotd_client_capability *capa;
977 	size_t datalen;
978 	char *key, *value = NULL;
979 
980 	if (client->capabilities == NULL ||
981 	    client->ncapabilities >= client->ncapa_alloc) {
982 		return got_error_msg(GOT_ERR_BAD_REQUEST,
983 		    "unexpected capability received");
984 	}
985 
986 	memset(&icapa, 0, sizeof(icapa));
987 
988 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
989 	if (datalen < sizeof(icapa))
990 		return got_error(GOT_ERR_PRIVSEP_LEN);
991 	memcpy(&icapa, imsg->data, sizeof(icapa));
992 
993 	if (datalen != sizeof(icapa) + icapa.key_len + icapa.value_len)
994 		return got_error(GOT_ERR_PRIVSEP_LEN);
995 
996 	key = strndup(imsg->data + sizeof(icapa), icapa.key_len);
997 	if (key == NULL)
998 		return got_error_from_errno("strndup");
999 	if (icapa.value_len > 0) {
1000 		value = strndup(imsg->data + sizeof(icapa) + icapa.key_len,
1001 		    icapa.value_len);
1002 		if (value == NULL) {
1003 			free(key);
1004 			return got_error_from_errno("strndup");
1005 		}
1006 	}
1007 
1008 	capa = &client->capabilities[client->ncapabilities++];
1009 	capa->key = key;
1010 	capa->value = value;
1011 
1012 	if (value)
1013 		log_debug("uid %d: capability %s=%s", client->euid, key, value);
1014 	else
1015 		log_debug("uid %d: capability %s", client->euid, key);
1016 
1017 	return NULL;
1018 }
1019 
1020 static const struct got_error *
1021 forward_ref_update(struct gotd_session_client *client, struct imsg *imsg)
1022 {
1023 	const struct got_error *err = NULL;
1024 	struct gotd_imsg_ref_update ireq;
1025 	struct gotd_imsg_ref_update *iref = NULL;
1026 	size_t datalen;
1027 
1028 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1029 	if (datalen < sizeof(ireq))
1030 		return got_error(GOT_ERR_PRIVSEP_LEN);
1031 	memcpy(&ireq, imsg->data, sizeof(ireq));
1032 	if (datalen != sizeof(ireq) + ireq.name_len)
1033 		return got_error(GOT_ERR_PRIVSEP_LEN);
1034 
1035 	iref = malloc(datalen);
1036 	if (iref == NULL)
1037 		return got_error_from_errno("malloc");
1038 	memcpy(iref, imsg->data, datalen);
1039 
1040 	if (gotd_imsg_compose_event(&gotd_session.repo_child_iev,
1041 	    GOTD_IMSG_REF_UPDATE, PROC_SESSION_WRITE, -1,
1042 	    iref, datalen) == -1)
1043 		err = got_error_from_errno("imsg compose REF_UPDATE");
1044 	free(iref);
1045 	return err;
1046 }
1047 
1048 static int
1049 client_has_capability(struct gotd_session_client *client, const char *capastr)
1050 {
1051 	struct gotd_client_capability *capa;
1052 	size_t i;
1053 
1054 	if (client->ncapabilities == 0)
1055 		return 0;
1056 
1057 	for (i = 0; i < client->ncapabilities; i++) {
1058 		capa = &client->capabilities[i];
1059 		if (strcmp(capa->key, capastr) == 0)
1060 			return 1;
1061 	}
1062 
1063 	return 0;
1064 }
1065 
1066 static const struct got_error *
1067 recv_packfile(struct gotd_session_client *client)
1068 {
1069 	const struct got_error *err = NULL;
1070 	struct gotd_imsg_recv_packfile ipack;
1071 	char *basepath = NULL, *pack_path = NULL, *idx_path = NULL;
1072 	int packfd = -1, idxfd = -1;
1073 	int pipe[2] = { -1, -1 };
1074 
1075 	if (client->packfile_path) {
1076 		return got_error_fmt(GOT_ERR_PRIVSEP_MSG,
1077 		    "uid %d already has a pack file", client->euid);
1078 	}
1079 
1080 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pipe) == -1)
1081 		return got_error_from_errno("socketpair");
1082 
1083 	/* Send pack pipe end 0 to repo child process. */
1084 	if (gotd_imsg_compose_event(&gotd_session.repo_child_iev,
1085 	    GOTD_IMSG_PACKFILE_PIPE, PROC_SESSION_WRITE, pipe[0],
1086 	        NULL, 0) == -1) {
1087 		err = got_error_from_errno("imsg compose PACKFILE_PIPE");
1088 		pipe[0] = -1;
1089 		goto done;
1090 	}
1091 	pipe[0] = -1;
1092 
1093 	/* Send pack pipe end 1 to gotsh(1) (expects just an fd, no data). */
1094 	if (gotd_imsg_compose_event(&client->iev,
1095 	    GOTD_IMSG_PACKFILE_PIPE, PROC_SESSION_WRITE, pipe[1],
1096 	    NULL, 0) == -1)
1097 		err = got_error_from_errno("imsg compose PACKFILE_PIPE");
1098 	pipe[1] = -1;
1099 
1100 	if (asprintf(&basepath, "%s/%s/receiving-from-uid-%d.pack",
1101 	    got_repo_get_path(gotd_session.repo), GOT_OBJECTS_PACK_DIR,
1102 	    client->euid) == -1) {
1103 		err = got_error_from_errno("asprintf");
1104 		goto done;
1105 	}
1106 
1107 	err = got_opentemp_named_fd(&pack_path, &packfd, basepath, "");
1108 	if (err)
1109 		goto done;
1110 	if (fchmod(packfd, GOT_DEFAULT_PACK_MODE) == -1) {
1111 		err = got_error_from_errno2("fchmod", pack_path);
1112 		goto done;
1113 	}
1114 
1115 	free(basepath);
1116 	if (asprintf(&basepath, "%s/%s/receiving-from-uid-%d.idx",
1117 	    got_repo_get_path(gotd_session.repo), GOT_OBJECTS_PACK_DIR,
1118 	    client->euid) == -1) {
1119 		err = got_error_from_errno("asprintf");
1120 		basepath = NULL;
1121 		goto done;
1122 	}
1123 	err = got_opentemp_named_fd(&idx_path, &idxfd, basepath, "");
1124 	if (err)
1125 		goto done;
1126 	if (fchmod(idxfd, GOT_DEFAULT_PACK_MODE) == -1) {
1127 		err = got_error_from_errno2("fchmod", idx_path);
1128 		goto done;
1129 	}
1130 
1131 	if (gotd_imsg_compose_event(&gotd_session.repo_child_iev,
1132 	    GOTD_IMSG_PACKIDX_FILE, PROC_SESSION_WRITE,
1133 	    idxfd, NULL, 0) == -1) {
1134 		err = got_error_from_errno("imsg compose PACKIDX_FILE");
1135 		idxfd = -1;
1136 		goto done;
1137 	}
1138 	idxfd = -1;
1139 
1140 	memset(&ipack, 0, sizeof(ipack));
1141 	if (client_has_capability(client, GOT_CAPA_REPORT_STATUS))
1142 		ipack.report_status = 1;
1143 
1144 	if (gotd_imsg_compose_event(&gotd_session.repo_child_iev,
1145 	    GOTD_IMSG_RECV_PACKFILE, PROC_SESSION_WRITE, packfd,
1146 	    &ipack, sizeof(ipack)) == -1) {
1147 		err = got_error_from_errno("imsg compose RECV_PACKFILE");
1148 		packfd = -1;
1149 		goto done;
1150 	}
1151 	packfd = -1;
1152 
1153 done:
1154 	free(basepath);
1155 	if (pipe[0] != -1 && close(pipe[0]) == -1 && err == NULL)
1156 		err = got_error_from_errno("close");
1157 	if (pipe[1] != -1 && close(pipe[1]) == -1 && err == NULL)
1158 		err = got_error_from_errno("close");
1159 	if (packfd != -1 && close(packfd) == -1 && err == NULL)
1160 		err = got_error_from_errno("close");
1161 	if (idxfd != -1 && close(idxfd) == -1 && err == NULL)
1162 		err = got_error_from_errno("close");
1163 	if (err) {
1164 		free(pack_path);
1165 		free(idx_path);
1166 	} else {
1167 		client->packfile_path = pack_path;
1168 		client->packidx_path = idx_path;
1169 	}
1170 	return err;
1171 }
1172 
1173 static void
1174 session_dispatch_client(int fd, short events, void *arg)
1175 {
1176 	struct gotd_imsgev *iev = arg;
1177 	struct imsgbuf *ibuf = &iev->ibuf;
1178 	struct gotd_session_client *client = &gotd_session_client;
1179 	const struct got_error *err = NULL;
1180 	struct imsg imsg;
1181 	ssize_t n;
1182 
1183 	if (events & EV_WRITE) {
1184 		while (ibuf->w.queued) {
1185 			n = msgbuf_write(&ibuf->w);
1186 			if (n == -1 && errno == EPIPE) {
1187 				/*
1188 				 * The client has closed its socket.
1189 				 * This can happen when Git clients are
1190 				 * done sending pack file data.
1191 				 */
1192 				msgbuf_clear(&ibuf->w);
1193 				continue;
1194 			} else if (n == -1 && errno != EAGAIN) {
1195 				err = got_error_from_errno("imsg_flush");
1196 				disconnect_on_error(client, err);
1197 				return;
1198 			}
1199 			if (n == 0) {
1200 				/* Connection closed. */
1201 				err = got_error(GOT_ERR_EOF);
1202 				disconnect_on_error(client, err);
1203 				return;
1204 			}
1205 		}
1206 
1207 		if (client->flush_disconnect) {
1208 			disconnect(client);
1209 			return;
1210 		}
1211 	}
1212 
1213 	if ((events & EV_READ) == 0)
1214 		return;
1215 
1216 	memset(&imsg, 0, sizeof(imsg));
1217 
1218 	while (err == NULL) {
1219 		err = gotd_imsg_recv(&imsg, ibuf, 0);
1220 		if (err) {
1221 			if (err->code == GOT_ERR_PRIVSEP_READ)
1222 				err = NULL;
1223 			else if (err->code == GOT_ERR_EOF &&
1224 			    gotd_session.state ==
1225 			    GOTD_STATE_EXPECT_CAPABILITIES) {
1226 				/*
1227 				 * The client has closed its socket before
1228 				 * sending its capability announcement.
1229 				 * This can happen when Git clients have
1230 				 * no ref-updates to send.
1231 				 */
1232 				disconnect_on_error(client, err);
1233 				return;
1234 			}
1235 			break;
1236 		}
1237 
1238 		evtimer_del(&client->tmo);
1239 
1240 		switch (imsg.hdr.type) {
1241 		case GOTD_IMSG_CAPABILITIES:
1242 			if (gotd_session.state !=
1243 			    GOTD_STATE_EXPECT_CAPABILITIES) {
1244 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1245 				    "unexpected capabilities received");
1246 				break;
1247 			}
1248 			log_debug("receiving capabilities from uid %d",
1249 			    client->euid);
1250 			err = recv_capabilities(client, &imsg);
1251 			break;
1252 		case GOTD_IMSG_CAPABILITY:
1253 			if (gotd_session.state != GOTD_STATE_EXPECT_CAPABILITIES) {
1254 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1255 				    "unexpected capability received");
1256 				break;
1257 			}
1258 			err = recv_capability(client, &imsg);
1259 			if (err || client->ncapabilities < client->ncapa_alloc)
1260 				break;
1261 			gotd_session.state = GOTD_STATE_EXPECT_REF_UPDATE;
1262 			client->accept_flush_pkt = 1;
1263 			log_debug("uid %d: expecting ref-update-lines",
1264 			    client->euid);
1265 			break;
1266 		case GOTD_IMSG_REF_UPDATE:
1267 			if (gotd_session.state != GOTD_STATE_EXPECT_REF_UPDATE &&
1268 			    gotd_session.state !=
1269 			    GOTD_STATE_EXPECT_MORE_REF_UPDATES) {
1270 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1271 				    "unexpected ref-update-line received");
1272 				break;
1273 			}
1274 			log_debug("received ref-update-line from uid %d",
1275 			    client->euid);
1276 			err = forward_ref_update(client, &imsg);
1277 			if (err)
1278 				break;
1279 			gotd_session.state = GOTD_STATE_EXPECT_MORE_REF_UPDATES;
1280 			client->accept_flush_pkt = 1;
1281 			break;
1282 		case GOTD_IMSG_FLUSH:
1283 			if (gotd_session.state !=
1284 			    GOTD_STATE_EXPECT_MORE_REF_UPDATES) {
1285 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1286 				    "unexpected flush-pkt received");
1287 				break;
1288 			}
1289 			if (!client->accept_flush_pkt) {
1290 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1291 				    "unexpected flush-pkt received");
1292 				break;
1293 			}
1294 
1295 			/*
1296 			 * Accept just one flush packet at a time.
1297 			 * Future client state transitions will set this flag
1298 			 * again if another flush packet is expected.
1299 			 */
1300 			client->accept_flush_pkt = 0;
1301 
1302 			log_debug("received flush-pkt from uid %d",
1303 			    client->euid);
1304 			if (gotd_session.state ==
1305 			    GOTD_STATE_EXPECT_MORE_REF_UPDATES) {
1306 				gotd_session.state = GOTD_STATE_EXPECT_PACKFILE;
1307 				log_debug("uid %d: expecting packfile",
1308 				    client->euid);
1309 				err = recv_packfile(client);
1310 			} else {
1311 				/* should not happen, see above */
1312 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1313 				    "unexpected client state");
1314 				break;
1315 			}
1316 			break;
1317 		default:
1318 			log_debug("unexpected imsg %d", imsg.hdr.type);
1319 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1320 			break;
1321 		}
1322 
1323 		imsg_free(&imsg);
1324 	}
1325 
1326 	if (err) {
1327 		if (err->code != GOT_ERR_EOF ||
1328 		    gotd_session.state != GOTD_STATE_EXPECT_PACKFILE)
1329 			disconnect_on_error(client, err);
1330 	} else {
1331 		gotd_imsg_event_add(iev);
1332 		evtimer_add(&client->tmo, &gotd_session.request_timeout);
1333 	}
1334 }
1335 
1336 static const struct got_error *
1337 list_refs_request(void)
1338 {
1339 	static const struct got_error *err;
1340 	struct gotd_session_client *client = &gotd_session_client;
1341 	struct gotd_imsgev *iev = &gotd_session.repo_child_iev;
1342 	int fd;
1343 
1344 	if (gotd_session.state != GOTD_STATE_EXPECT_LIST_REFS)
1345 		return got_error(GOT_ERR_PRIVSEP_MSG);
1346 
1347 	fd = dup(client->fd);
1348 	if (fd == -1)
1349 		return got_error_from_errno("dup");
1350 
1351 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_LIST_REFS_INTERNAL,
1352 	    PROC_SESSION_WRITE, fd, NULL, 0) == -1) {
1353 		err = got_error_from_errno("imsg compose LIST_REFS_INTERNAL");
1354 		close(fd);
1355 		return err;
1356 	}
1357 
1358 	gotd_session.state = GOTD_STATE_EXPECT_CAPABILITIES;
1359 	log_debug("uid %d: expecting capabilities", client->euid);
1360 	return NULL;
1361 }
1362 
1363 static const struct got_error *
1364 recv_connect(struct imsg *imsg)
1365 {
1366 	struct gotd_session_client *client = &gotd_session_client;
1367 	struct gotd_imsg_connect iconnect;
1368 	size_t datalen;
1369 
1370 	if (gotd_session.state != GOTD_STATE_EXPECT_LIST_REFS)
1371 		return got_error(GOT_ERR_PRIVSEP_MSG);
1372 
1373 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1374 	if (datalen < sizeof(iconnect))
1375 		return got_error(GOT_ERR_PRIVSEP_LEN);
1376 	memcpy(&iconnect, imsg->data, sizeof(iconnect));
1377 	if (iconnect.username_len == 0 ||
1378 	    datalen != sizeof(iconnect) + iconnect.username_len)
1379 		return got_error(GOT_ERR_PRIVSEP_LEN);
1380 
1381 	client->euid = iconnect.euid;
1382 	client->egid = iconnect.egid;
1383 	client->fd = imsg_get_fd(imsg);
1384 	if (client->fd == -1)
1385 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
1386 
1387 	client->username = strndup(imsg->data + sizeof(iconnect),
1388 	    iconnect.username_len);
1389 	if (client->username == NULL)
1390 		return got_error_from_errno("strndup");
1391 
1392 	imsg_init(&client->iev.ibuf, client->fd);
1393 	client->iev.handler = session_dispatch_client;
1394 	client->iev.events = EV_READ;
1395 	client->iev.handler_arg = NULL;
1396 	event_set(&client->iev.ev, client->iev.ibuf.fd, EV_READ,
1397 	    session_dispatch_client, &client->iev);
1398 	gotd_imsg_event_add(&client->iev);
1399 	evtimer_set(&client->tmo, gotd_request_timeout, client);
1400 
1401 	return NULL;
1402 }
1403 
1404 static void
1405 session_dispatch_notifier(int fd, short event, void *arg)
1406 {
1407 	const struct got_error *err;
1408 	struct gotd_session_client *client = &gotd_session_client;
1409 	struct gotd_imsgev *iev = arg;
1410 	struct imsgbuf *ibuf = &iev->ibuf;
1411 	ssize_t n;
1412 	int shut = 0;
1413 	struct imsg imsg;
1414 	struct gotd_session_notif *notif;
1415 
1416 	if (event & EV_READ) {
1417 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1418 			fatal("imsg_read error");
1419 		if (n == 0) {
1420 			/* Connection closed. */
1421 			shut = 1;
1422 			goto done;
1423 		}
1424 	}
1425 
1426 	if (event & EV_WRITE) {
1427 		n = msgbuf_write(&ibuf->w);
1428 		if (n == -1 && errno != EAGAIN)
1429 			fatal("msgbuf_write");
1430 		if (n == 0) {
1431 			/* Connection closed. */
1432 			shut = 1;
1433 			goto done;
1434 		}
1435 	}
1436 
1437 	for (;;) {
1438 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1439 			fatal("%s: imsg_get error", __func__);
1440 		if (n == 0)	/* No more messages. */
1441 			break;
1442 
1443 		switch (imsg.hdr.type) {
1444 		case GOTD_IMSG_NOTIFICATION_SENT:
1445 			if (gotd_session.state != GOTD_STATE_NOTIFY) {
1446 				log_warn("unexpected imsg %d", imsg.hdr.type);
1447 				break;
1448 			}
1449 			notif = STAILQ_FIRST(&notifications);
1450 			if (notif == NULL) {
1451 				disconnect(client);
1452 				break; /* NOTREACHED */
1453 			}
1454 			/* Request content for the next notification. */
1455 			err = request_notification(notif);
1456 			if (err) {
1457 				log_warn("could not send notification: %s",
1458 				    err->msg);
1459 				disconnect(client);
1460 			}
1461 			break;
1462 		default:
1463 			log_debug("unexpected imsg %d", imsg.hdr.type);
1464 			break;
1465 		}
1466 
1467 		imsg_free(&imsg);
1468 	}
1469 done:
1470 	if (!shut) {
1471 		gotd_imsg_event_add(iev);
1472 	} else {
1473 		/* This pipe is dead. Remove its event handler */
1474 		event_del(&iev->ev);
1475 		imsg_clear(&iev->ibuf);
1476 		imsg_init(&iev->ibuf, -1);
1477 	}
1478 }
1479 
1480 static const struct got_error *
1481 recv_notifier(struct imsg *imsg)
1482 {
1483 	struct gotd_imsgev *iev = &gotd_session.notifier_iev;
1484 	struct gotd_session_client *client = &gotd_session_client;
1485 	size_t datalen;
1486 	int fd;
1487 
1488 	if (gotd_session.state != GOTD_STATE_EXPECT_LIST_REFS)
1489 		return got_error(GOT_ERR_PRIVSEP_MSG);
1490 
1491 	/* We should already have received a pipe to the listener. */
1492 	if (client->fd == -1)
1493 		return got_error(GOT_ERR_PRIVSEP_MSG);
1494 
1495 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1496 	if (datalen != 0)
1497 		return got_error(GOT_ERR_PRIVSEP_LEN);
1498 
1499 	fd = imsg_get_fd(imsg);
1500 	if (fd == -1)
1501 		return NULL; /* notifications unused */
1502 
1503 	imsg_init(&iev->ibuf, fd);
1504 	iev->handler = session_dispatch_notifier;
1505 	iev->events = EV_READ;
1506 	iev->handler_arg = NULL;
1507 	event_set(&iev->ev, iev->ibuf.fd, EV_READ,
1508 	    session_dispatch_notifier, iev);
1509 	gotd_imsg_event_add(iev);
1510 
1511 	return NULL;
1512 }
1513 
1514 static const struct got_error *
1515 recv_repo_child(struct imsg *imsg)
1516 {
1517 	struct gotd_imsg_connect_repo_child ichild;
1518 	struct gotd_session_client *client = &gotd_session_client;
1519 	size_t datalen;
1520 	int fd;
1521 
1522 	if (gotd_session.state != GOTD_STATE_EXPECT_LIST_REFS)
1523 		return got_error(GOT_ERR_PRIVSEP_MSG);
1524 
1525 	/* We should already have received a pipe to the listener. */
1526 	if (client->fd == -1)
1527 		return got_error(GOT_ERR_PRIVSEP_MSG);
1528 
1529 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1530 	if (datalen != sizeof(ichild))
1531 		return got_error(GOT_ERR_PRIVSEP_LEN);
1532 
1533 	memcpy(&ichild, imsg->data, sizeof(ichild));
1534 
1535 	if (ichild.proc_id != PROC_REPO_WRITE)
1536 		return got_error_msg(GOT_ERR_PRIVSEP_MSG,
1537 		    "bad child process type");
1538 
1539 	fd = imsg_get_fd(imsg);
1540 	if (fd == -1)
1541 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
1542 
1543 	imsg_init(&gotd_session.repo_child_iev.ibuf, fd);
1544 	gotd_session.repo_child_iev.handler = session_dispatch_repo_child;
1545 	gotd_session.repo_child_iev.events = EV_READ;
1546 	gotd_session.repo_child_iev.handler_arg = NULL;
1547 	event_set(&gotd_session.repo_child_iev.ev,
1548 	    gotd_session.repo_child_iev.ibuf.fd, EV_READ,
1549 	    session_dispatch_repo_child, &gotd_session.repo_child_iev);
1550 	gotd_imsg_event_add(&gotd_session.repo_child_iev);
1551 
1552 	/* The "recvfd" pledge promise is no longer needed. */
1553 	if (pledge("stdio rpath wpath cpath sendfd fattr flock", NULL) == -1)
1554 		fatal("pledge");
1555 
1556 	return NULL;
1557 }
1558 
1559 static void
1560 session_dispatch(int fd, short event, void *arg)
1561 {
1562 	struct gotd_imsgev *iev = arg;
1563 	struct imsgbuf *ibuf = &iev->ibuf;
1564 	struct gotd_session_client *client = &gotd_session_client;
1565 	ssize_t n;
1566 	int shut = 0;
1567 	struct imsg imsg;
1568 
1569 	if (event & EV_READ) {
1570 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1571 			fatal("imsg_read error");
1572 		if (n == 0) {
1573 			/* Connection closed. */
1574 			shut = 1;
1575 			goto done;
1576 		}
1577 	}
1578 
1579 	if (event & EV_WRITE) {
1580 		n = msgbuf_write(&ibuf->w);
1581 		if (n == -1 && errno != EAGAIN)
1582 			fatal("msgbuf_write");
1583 		if (n == 0) {
1584 			/* Connection closed. */
1585 			shut = 1;
1586 			goto done;
1587 		}
1588 	}
1589 
1590 	for (;;) {
1591 		const struct got_error *err = NULL;
1592 		uint32_t client_id = 0;
1593 		int do_disconnect = 0, do_list_refs = 0;
1594 
1595 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1596 			fatal("%s: imsg_get error", __func__);
1597 		if (n == 0)	/* No more messages. */
1598 			break;
1599 
1600 		switch (imsg.hdr.type) {
1601 		case GOTD_IMSG_ERROR:
1602 			do_disconnect = 1;
1603 			err = gotd_imsg_recv_error(&client_id, &imsg);
1604 			break;
1605 		case GOTD_IMSG_CONNECT:
1606 			err = recv_connect(&imsg);
1607 			break;
1608 		case GOTD_IMSG_DISCONNECT:
1609 			do_disconnect = 1;
1610 			break;
1611 		case GOTD_IMSG_CONNECT_NOTIFIER:
1612 			err = recv_notifier(&imsg);
1613 			break;
1614 		case GOTD_IMSG_CONNECT_REPO_CHILD:
1615 			err = recv_repo_child(&imsg);
1616 			if (err)
1617 				break;
1618 			do_list_refs = 1;
1619 			break;
1620 		default:
1621 			log_debug("unexpected imsg %d", imsg.hdr.type);
1622 			break;
1623 		}
1624 		imsg_free(&imsg);
1625 
1626 		if (do_disconnect) {
1627 			if (err)
1628 				disconnect_on_error(client, err);
1629 			else
1630 				disconnect(client);
1631 		} else if (do_list_refs)
1632 			err = list_refs_request();
1633 
1634 		if (err)
1635 			log_warnx("uid %d: %s", client->euid, err->msg);
1636 	}
1637 done:
1638 	if (!shut) {
1639 		gotd_imsg_event_add(iev);
1640 	} else {
1641 		/* This pipe is dead. Remove its event handler */
1642 		event_del(&iev->ev);
1643 		event_loopexit(NULL);
1644 	}
1645 }
1646 
1647 void
1648 session_write_main(const char *title, const char *repo_path,
1649     int *pack_fds, int *temp_fds, struct timeval *request_timeout,
1650     struct gotd_repo *repo_cfg)
1651 {
1652 	const struct got_error *err = NULL;
1653 	struct event evsigint, evsigterm, evsighup, evsigusr1;
1654 
1655 	STAILQ_INIT(&notifications);
1656 
1657 	gotd_session.title = title;
1658 	gotd_session.pid = getpid();
1659 	gotd_session.pack_fds = pack_fds;
1660 	gotd_session.temp_fds = temp_fds;
1661 	memcpy(&gotd_session.request_timeout, request_timeout,
1662 	    sizeof(gotd_session.request_timeout));
1663 	gotd_session.repo_cfg = repo_cfg;
1664 
1665 	imsg_init(&gotd_session.notifier_iev.ibuf, -1);
1666 
1667 	err = got_repo_open(&gotd_session.repo, repo_path, NULL, pack_fds);
1668 	if (err)
1669 		goto done;
1670 	if (!got_repo_is_bare(gotd_session.repo)) {
1671 		err = got_error_msg(GOT_ERR_NOT_GIT_REPO,
1672 		    "bare git repository required");
1673 		goto done;
1674 	}
1675 
1676 	got_repo_temp_fds_set(gotd_session.repo, temp_fds);
1677 
1678 	signal_set(&evsigint, SIGINT, session_write_sighdlr, NULL);
1679 	signal_set(&evsigterm, SIGTERM, session_write_sighdlr, NULL);
1680 	signal_set(&evsighup, SIGHUP, session_write_sighdlr, NULL);
1681 	signal_set(&evsigusr1, SIGUSR1, session_write_sighdlr, NULL);
1682 	signal(SIGPIPE, SIG_IGN);
1683 
1684 	signal_add(&evsigint, NULL);
1685 	signal_add(&evsigterm, NULL);
1686 	signal_add(&evsighup, NULL);
1687 	signal_add(&evsigusr1, NULL);
1688 
1689 	gotd_session.state = GOTD_STATE_EXPECT_LIST_REFS;
1690 
1691 	gotd_session_client.fd = -1;
1692 	gotd_session_client.nref_updates = -1;
1693 	gotd_session_client.delta_cache_fd = -1;
1694 	gotd_session_client.accept_flush_pkt = 1;
1695 
1696 	imsg_init(&gotd_session.parent_iev.ibuf, GOTD_FILENO_MSG_PIPE);
1697 	gotd_session.parent_iev.handler = session_dispatch;
1698 	gotd_session.parent_iev.events = EV_READ;
1699 	gotd_session.parent_iev.handler_arg = NULL;
1700 	event_set(&gotd_session.parent_iev.ev, gotd_session.parent_iev.ibuf.fd,
1701 	    EV_READ, session_dispatch, &gotd_session.parent_iev);
1702 	if (gotd_imsg_compose_event(&gotd_session.parent_iev,
1703 	    GOTD_IMSG_CLIENT_SESSION_READY, PROC_SESSION_WRITE,
1704 	    -1, NULL, 0) == -1) {
1705 		err = got_error_from_errno("imsg compose CLIENT_SESSION_READY");
1706 		goto done;
1707 	}
1708 
1709 	event_dispatch();
1710 done:
1711 	if (err)
1712 		log_warnx("%s: %s", title, err->msg);
1713 	session_write_shutdown();
1714 }
1715 
1716 static void
1717 session_write_shutdown(void)
1718 {
1719 	struct gotd_session_notif *notif;
1720 
1721 	log_debug("%s: shutting down", gotd_session.title);
1722 
1723 	while (!STAILQ_EMPTY(&notifications)) {
1724 		notif = STAILQ_FIRST(&notifications);
1725 		STAILQ_REMOVE_HEAD(&notifications, entry);
1726 		if (notif->fd != -1)
1727 			close(notif->fd);
1728 		free(notif->refname);
1729 		free(notif);
1730 	}
1731 
1732 	if (gotd_session.repo)
1733 		got_repo_close(gotd_session.repo);
1734 	got_repo_pack_fds_close(gotd_session.pack_fds);
1735 	got_repo_temp_fds_close(gotd_session.temp_fds);
1736 	free(gotd_session_client.username);
1737 	exit(0);
1738 }