Game of Trees Repos

Blob

Date:: Thu Jun 22 13:10:34 2023 UTC
Message:: unveil repositories read-only in gotd session process while serving fetches ok op@
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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/socket.h>
20 #include <sys/stat.h>
21 #include <sys/uio.h>
22 
23 #include <errno.h>
24 #include <event.h>
25 #include <limits.h>
26 #include <signal.h>
27 #include <stdint.h>
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <imsg.h>
32 #include <unistd.h>
33 
34 #include "got_error.h"
35 #include "got_repository.h"
36 #include "got_object.h"
37 #include "got_path.h"
38 #include "got_reference.h"
39 #include "got_opentemp.h"
40 
41 #include "got_lib_hash.h"
42 #include "got_lib_delta.h"
43 #include "got_lib_object.h"
44 #include "got_lib_object_cache.h"
45 #include "got_lib_pack.h"
46 #include "got_lib_repository.h"
47 #include "got_lib_gitproto.h"
48 
49 #include "gotd.h"
50 #include "log.h"
51 #include "session.h"
52 
53 
54 static struct gotd_session {
55 	pid_t pid;
56 	const char *title;
57 	struct got_repository *repo;
58 	int *pack_fds;
59 	int *temp_fds;
60 	struct gotd_imsgev parent_iev;
61 	struct timeval request_timeout;
62 	enum gotd_procid proc_id;
63 } gotd_session;
64 
65 static struct gotd_session_client {
66 	enum gotd_session_state		 state;
67 	int				 is_writing;
68 	struct gotd_client_capability	*capabilities;
69 	size_t				 ncapa_alloc;
70 	size_t				 ncapabilities;
71 	uint32_t			 id;
72 	int				 fd;
73 	int				 delta_cache_fd;
74 	struct gotd_imsgev		 iev;
75 	struct gotd_imsgev		 repo_child_iev;
76 	struct event			 tmo;
77 	uid_t				 euid;
78 	gid_t				 egid;
79 	char				*packfile_path;
80 	char				*packidx_path;
81 	int				 nref_updates;
82 	int				 accept_flush_pkt;
83 } gotd_session_client;
84 
85 void gotd_session_sighdlr(int sig, short event, void *arg);
86 static void gotd_session_shutdown(void);
87 
88 static void
89 disconnect(struct gotd_session_client *client)
90 {
91 	log_debug("uid %d: disconnecting", client->euid);
92 
93 	if (gotd_imsg_compose_event(&gotd_session.parent_iev,
94 	    GOTD_IMSG_DISCONNECT, gotd_session.proc_id, -1, NULL, 0) == -1)
95 		log_warn("imsg compose DISCONNECT");
96 
97 	imsg_clear(&client->repo_child_iev.ibuf);
98 	event_del(&client->repo_child_iev.ev);
99 	evtimer_del(&client->tmo);
100 	close(client->fd);
101 	if (client->delta_cache_fd != -1)
102 		close(client->delta_cache_fd);
103 	if (client->packfile_path) {
104 		if (unlink(client->packfile_path) == -1 && errno != ENOENT)
105 			log_warn("unlink %s: ", client->packfile_path);
106 		free(client->packfile_path);
107 	}
108 	if (client->packidx_path) {
109 		if (unlink(client->packidx_path) == -1 && errno != ENOENT)
110 			log_warn("unlink %s: ", client->packidx_path);
111 		free(client->packidx_path);
112 	}
113 	free(client->capabilities);
114 
115 	gotd_session_shutdown();
116 }
117 
118 static void
119 disconnect_on_error(struct gotd_session_client *client,
120     const struct got_error *err)
121 {
122 	struct imsgbuf ibuf;
123 
124 	log_warnx("uid %d: %s", client->euid, err->msg);
125 	if (err->code != GOT_ERR_EOF) {
126 		imsg_init(&ibuf, client->fd);
127 		gotd_imsg_send_error(&ibuf, 0, gotd_session.proc_id, err);
128 		imsg_clear(&ibuf);
129 	}
130 
131 	disconnect(client);
132 }
133 
134 static void
135 gotd_request_timeout(int fd, short events, void *arg)
136 {
137 	struct gotd_session_client *client = arg;
138 
139 	log_debug("disconnecting uid %d due to timeout", client->euid);
140 	disconnect(client);
141 }
142 
143 void
144 gotd_session_sighdlr(int sig, short event, void *arg)
145 {
146 	/*
147 	 * Normal signal handler rules don't apply because libevent
148 	 * decouples for us.
149 	 */
150 
151 	switch (sig) {
152 	case SIGHUP:
153 		log_info("%s: ignoring SIGHUP", __func__);
154 		break;
155 	case SIGUSR1:
156 		log_info("%s: ignoring SIGUSR1", __func__);
157 		break;
158 	case SIGTERM:
159 	case SIGINT:
160 		gotd_session_shutdown();
161 		/* NOTREACHED */
162 		break;
163 	default:
164 		fatalx("unexpected signal");
165 	}
166 }
167 
168 static const struct got_error *
169 recv_packfile_done(uint32_t *client_id, struct imsg *imsg)
170 {
171 	struct gotd_imsg_packfile_done idone;
172 	size_t datalen;
173 
174 	log_debug("packfile-done received");
175 
176 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
177 	if (datalen != sizeof(idone))
178 		return got_error(GOT_ERR_PRIVSEP_LEN);
179 	memcpy(&idone, imsg->data, sizeof(idone));
180 
181 	*client_id = idone.client_id;
182 	return NULL;
183 }
184 
185 static const struct got_error *
186 recv_packfile_install(uint32_t *client_id, struct imsg *imsg)
187 {
188 	struct gotd_imsg_packfile_install inst;
189 	size_t datalen;
190 
191 	log_debug("packfile-install received");
192 
193 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
194 	if (datalen != sizeof(inst))
195 		return got_error(GOT_ERR_PRIVSEP_LEN);
196 	memcpy(&inst, imsg->data, sizeof(inst));
197 
198 	*client_id = inst.client_id;
199 	return NULL;
200 }
201 
202 static const struct got_error *
203 recv_ref_updates_start(uint32_t *client_id, struct imsg *imsg)
204 {
205 	struct gotd_imsg_ref_updates_start istart;
206 	size_t datalen;
207 
208 	log_debug("ref-updates-start received");
209 
210 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
211 	if (datalen != sizeof(istart))
212 		return got_error(GOT_ERR_PRIVSEP_LEN);
213 	memcpy(&istart, imsg->data, sizeof(istart));
214 
215 	*client_id = istart.client_id;
216 	return NULL;
217 }
218 
219 static const struct got_error *
220 recv_ref_update(uint32_t *client_id, struct imsg *imsg)
221 {
222 	struct gotd_imsg_ref_update iref;
223 	size_t datalen;
224 
225 	log_debug("ref-update received");
226 
227 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
228 	if (datalen < sizeof(iref))
229 		return got_error(GOT_ERR_PRIVSEP_LEN);
230 	memcpy(&iref, imsg->data, sizeof(iref));
231 
232 	*client_id = iref.client_id;
233 	return NULL;
234 }
235 
236 static const struct got_error *
237 send_ref_update_ok(struct gotd_session_client *client,
238     struct gotd_imsg_ref_update *iref, const char *refname)
239 {
240 	struct gotd_imsg_ref_update_ok iok;
241 	struct gotd_imsgev *iev = &client->iev;
242 	struct ibuf *wbuf;
243 	size_t len;
244 
245 	memset(&iok, 0, sizeof(iok));
246 	iok.client_id = client->id;
247 	memcpy(iok.old_id, iref->old_id, SHA1_DIGEST_LENGTH);
248 	memcpy(iok.new_id, iref->new_id, SHA1_DIGEST_LENGTH);
249 	iok.name_len = strlen(refname);
250 
251 	len = sizeof(iok) + iok.name_len;
252 	wbuf = imsg_create(&iev->ibuf, GOTD_IMSG_REF_UPDATE_OK,
253 	    gotd_session.proc_id, gotd_session.pid, len);
254 	if (wbuf == NULL)
255 		return got_error_from_errno("imsg_create REF_UPDATE_OK");
256 
257 	if (imsg_add(wbuf, &iok, sizeof(iok)) == -1)
258 		return got_error_from_errno("imsg_add REF_UPDATE_OK");
259 	if (imsg_add(wbuf, refname, iok.name_len) == -1)
260 		return got_error_from_errno("imsg_add REF_UPDATE_OK");
261 
262 	wbuf->fd = -1;
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 	    gotd_session.proc_id, -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 	ing.client_id = client->id;
289 	memcpy(ing.old_id, iref->old_id, SHA1_DIGEST_LENGTH);
290 	memcpy(ing.new_id, iref->new_id, SHA1_DIGEST_LENGTH);
291 	ing.name_len = strlen(refname);
292 
293 	ng_err = got_error_fmt(GOT_ERR_REF_BUSY, "%s", reason);
294 	ing.reason_len = strlen(ng_err->msg);
295 
296 	len = sizeof(ing) + ing.name_len + ing.reason_len;
297 	wbuf = imsg_create(&iev->ibuf, GOTD_IMSG_REF_UPDATE_NG,
298 	    gotd_session.proc_id, gotd_session.pid, len);
299 	if (wbuf == NULL)
300 		return got_error_from_errno("imsg_create REF_UPDATE_NG");
301 
302 	if (imsg_add(wbuf, &ing, sizeof(ing)) == -1)
303 		return got_error_from_errno("imsg_add REF_UPDATE_NG");
304 	if (imsg_add(wbuf, refname, ing.name_len) == -1)
305 		return got_error_from_errno("imsg_add REF_UPDATE_NG");
306 	if (imsg_add(wbuf, ng_err->msg, ing.reason_len) == -1)
307 		return got_error_from_errno("imsg_add REF_UPDATE_NG");
308 
309 	wbuf->fd = -1;
310 	imsg_close(&iev->ibuf, wbuf);
311 	gotd_imsg_event_add(iev);
312 	return NULL;
313 }
314 
315 static const struct got_error *
316 install_pack(struct gotd_session_client *client, const char *repo_path,
317     struct imsg *imsg)
318 {
319 	const struct got_error *err = NULL;
320 	struct gotd_imsg_packfile_install inst;
321 	char hex[SHA1_DIGEST_STRING_LENGTH];
322 	size_t datalen;
323 	char *packfile_path = NULL, *packidx_path = NULL;
324 
325 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
326 	if (datalen != sizeof(inst))
327 		return got_error(GOT_ERR_PRIVSEP_LEN);
328 	memcpy(&inst, imsg->data, sizeof(inst));
329 
330 	if (client->packfile_path == NULL)
331 		return got_error_msg(GOT_ERR_BAD_REQUEST,
332 		    "client has no pack file");
333 	if (client->packidx_path == NULL)
334 		return got_error_msg(GOT_ERR_BAD_REQUEST,
335 		    "client has no pack file index");
336 
337 	if (got_sha1_digest_to_str(inst.pack_sha1, hex, sizeof(hex)) == NULL)
338 		return got_error_msg(GOT_ERR_NO_SPACE,
339 		    "could not convert pack file SHA1 to hex");
340 
341 	if (asprintf(&packfile_path, "/%s/%s/pack-%s.pack",
342 	    repo_path, GOT_OBJECTS_PACK_DIR, hex) == -1) {
343 		err = got_error_from_errno("asprintf");
344 		goto done;
345 	}
346 
347 	if (asprintf(&packidx_path, "/%s/%s/pack-%s.idx",
348 	    repo_path, GOT_OBJECTS_PACK_DIR, hex) == -1) {
349 		err = got_error_from_errno("asprintf");
350 		goto done;
351 	}
352 
353 	if (rename(client->packfile_path, packfile_path) == -1) {
354 		err = got_error_from_errno3("rename", client->packfile_path,
355 		    packfile_path);
356 		goto done;
357 	}
358 
359 	free(client->packfile_path);
360 	client->packfile_path = NULL;
361 
362 	if (rename(client->packidx_path, packidx_path) == -1) {
363 		err = got_error_from_errno3("rename", client->packidx_path,
364 		    packidx_path);
365 		goto done;
366 	}
367 
368 	free(client->packidx_path);
369 	client->packidx_path = NULL;
370 done:
371 	free(packfile_path);
372 	free(packidx_path);
373 	return err;
374 }
375 
376 static const struct got_error *
377 begin_ref_updates(struct gotd_session_client *client, struct imsg *imsg)
378 {
379 	struct gotd_imsg_ref_updates_start istart;
380 	size_t datalen;
381 
382 	if (client->nref_updates != -1)
383 		return got_error(GOT_ERR_PRIVSEP_MSG);
384 
385 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
386 	if (datalen != sizeof(istart))
387 		return got_error(GOT_ERR_PRIVSEP_LEN);
388 	memcpy(&istart, imsg->data, sizeof(istart));
389 
390 	if (istart.nref_updates <= 0)
391 		return got_error(GOT_ERR_PRIVSEP_MSG);
392 
393 	client->nref_updates = istart.nref_updates;
394 	return NULL;
395 }
396 
397 static const struct got_error *
398 update_ref(int *shut, struct gotd_session_client *client,
399     const char *repo_path, struct imsg *imsg)
400 {
401 	const struct got_error *err = NULL;
402 	struct got_repository *repo = NULL;
403 	struct got_reference *ref = NULL;
404 	struct gotd_imsg_ref_update iref;
405 	struct got_object_id old_id, new_id;
406 	struct got_object_id *id = NULL;
407 	struct got_object *obj = NULL;
408 	char *refname = NULL;
409 	size_t datalen;
410 	int locked = 0;
411 	char hex1[SHA1_DIGEST_STRING_LENGTH];
412 	char hex2[SHA1_DIGEST_STRING_LENGTH];
413 
414 	log_debug("update-ref from uid %d", client->euid);
415 
416 	if (client->nref_updates <= 0)
417 		return got_error(GOT_ERR_PRIVSEP_MSG);
418 
419 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
420 	if (datalen < sizeof(iref))
421 		return got_error(GOT_ERR_PRIVSEP_LEN);
422 	memcpy(&iref, imsg->data, sizeof(iref));
423 	if (datalen != sizeof(iref) + iref.name_len)
424 		return got_error(GOT_ERR_PRIVSEP_LEN);
425 	refname = strndup(imsg->data + sizeof(iref), iref.name_len);
426 	if (refname == NULL)
427 		return got_error_from_errno("strndup");
428 
429 	log_debug("updating ref %s for uid %d", refname, client->euid);
430 
431 	err = got_repo_open(&repo, repo_path, NULL, NULL);
432 	if (err)
433 		goto done;
434 
435 	memcpy(old_id.sha1, iref.old_id, SHA1_DIGEST_LENGTH);
436 	memcpy(new_id.sha1, iref.new_id, SHA1_DIGEST_LENGTH);
437 	err = got_object_open(&obj, repo,
438 	    iref.delete_ref ? &old_id : &new_id);
439 	if (err)
440 		goto done;
441 
442 	if (iref.ref_is_new) {
443 		err = got_ref_open(&ref, repo, refname, 0);
444 		if (err) {
445 			if (err->code != GOT_ERR_NOT_REF)
446 				goto done;
447 			err = got_ref_alloc(&ref, refname, &new_id);
448 			if (err)
449 				goto done;
450 			err = got_ref_write(ref, repo); /* will lock/unlock */
451 			if (err)
452 				goto done;
453 		} else {
454 			err = got_ref_resolve(&id, repo, ref);
455 			if (err)
456 				goto done;
457 			got_object_id_hex(&new_id, hex1, sizeof(hex1));
458 			got_object_id_hex(id, hex2, sizeof(hex2));
459 			err = got_error_fmt(GOT_ERR_REF_BUSY,
460 			    "Addition %s: %s failed; %s: %s has been "
461 			    "created by someone else while transaction "
462 			    "was in progress",
463 			    got_ref_get_name(ref), hex1,
464 			    got_ref_get_name(ref), hex2);
465 			goto done;
466 		}
467 	} else if (iref.delete_ref) {
468 		err = got_ref_open(&ref, repo, refname, 1 /* lock */);
469 		if (err)
470 			goto done;
471 		locked = 1;
472 
473 		err = got_ref_resolve(&id, repo, ref);
474 		if (err)
475 			goto done;
476 
477 		if (got_object_id_cmp(id, &old_id) != 0) {
478 			got_object_id_hex(&old_id, hex1, sizeof(hex1));
479 			got_object_id_hex(id, hex2, sizeof(hex2));
480 			err = got_error_fmt(GOT_ERR_REF_BUSY,
481 			    "Deletion %s: %s failed; %s: %s has been "
482 			    "created by someone else while transaction "
483 			    "was in progress",
484 			    got_ref_get_name(ref), hex1,
485 			    got_ref_get_name(ref), hex2);
486 			goto done;
487 		}
488 
489 		err = got_ref_delete(ref, repo);
490 		if (err)
491 			goto done;
492 
493 		free(id);
494 		id = NULL;
495 	} else {
496 		err = got_ref_open(&ref, repo, refname, 1 /* lock */);
497 		if (err)
498 			goto done;
499 		locked = 1;
500 
501 		err = got_ref_resolve(&id, repo, ref);
502 		if (err)
503 			goto done;
504 
505 		if (got_object_id_cmp(id, &old_id) != 0) {
506 			got_object_id_hex(&old_id, hex1, sizeof(hex1));
507 			got_object_id_hex(id, hex2, sizeof(hex2));
508 			err = got_error_fmt(GOT_ERR_REF_BUSY,
509 			    "Update %s: %s failed; %s: %s has been "
510 			    "created by someone else while transaction "
511 			    "was in progress",
512 			    got_ref_get_name(ref), hex1,
513 			    got_ref_get_name(ref), hex2);
514 			goto done;
515 		}
516 
517 		if (got_object_id_cmp(&new_id, &old_id) != 0) {
518 			err = got_ref_change_ref(ref, &new_id);
519 			if (err)
520 				goto done;
521 
522 			err = got_ref_write(ref, repo);
523 			if (err)
524 				goto done;
525 		}
526 
527 		free(id);
528 		id = NULL;
529 	}
530 done:
531 	if (err) {
532 		if (err->code == GOT_ERR_LOCKFILE_TIMEOUT) {
533 			err = got_error_fmt(GOT_ERR_LOCKFILE_TIMEOUT,
534 			    "could not acquire exclusive file lock for %s",
535 			    refname);
536 		}
537 		send_ref_update_ng(client, &iref, refname, err->msg);
538 	} else
539 		send_ref_update_ok(client, &iref, refname);
540 
541 	if (client->nref_updates > 0) {
542 		client->nref_updates--;
543 		if (client->nref_updates == 0) {
544 			send_refs_updated(client);
545 			*shut = 1;
546 		}
547 
548 	}
549 	if (locked) {
550 		const struct got_error *unlock_err;
551 		unlock_err = got_ref_unlock(ref);
552 		if (unlock_err && err == NULL)
553 			err = unlock_err;
554 	}
555 	if (ref)
556 		got_ref_close(ref);
557 	if (obj)
558 		got_object_close(obj);
559 	if (repo)
560 		got_repo_close(repo);
561 	free(refname);
562 	free(id);
563 	return err;
564 }
565 
566 static void
567 session_dispatch_repo_child(int fd, short event, void *arg)
568 {
569 	struct gotd_imsgev *iev = arg;
570 	struct imsgbuf *ibuf = &iev->ibuf;
571 	struct gotd_session_client *client = &gotd_session_client;
572 	ssize_t n;
573 	int shut = 0;
574 	struct imsg imsg;
575 
576 	if (event & EV_READ) {
577 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
578 			fatal("imsg_read error");
579 		if (n == 0) {
580 			/* Connection closed. */
581 			shut = 1;
582 			goto done;
583 		}
584 	}
585 
586 	if (event & EV_WRITE) {
587 		n = msgbuf_write(&ibuf->w);
588 		if (n == -1 && errno != EAGAIN)
589 			fatal("msgbuf_write");
590 		if (n == 0) {
591 			/* Connection closed. */
592 			shut = 1;
593 			goto done;
594 		}
595 	}
596 
597 	for (;;) {
598 		const struct got_error *err = NULL;
599 		uint32_t client_id = 0;
600 		int do_disconnect = 0;
601 		int do_ref_updates = 0, do_ref_update = 0;
602 		int do_packfile_install = 0;
603 
604 		if ((n = imsg_get(ibuf, &imsg)) == -1)
605 			fatal("%s: imsg_get error", __func__);
606 		if (n == 0)	/* No more messages. */
607 			break;
608 
609 		switch (imsg.hdr.type) {
610 		case GOTD_IMSG_ERROR:
611 			do_disconnect = 1;
612 			err = gotd_imsg_recv_error(&client_id, &imsg);
613 			break;
614 		case GOTD_IMSG_PACKFILE_DONE:
615 			do_disconnect = 1;
616 			err = recv_packfile_done(&client_id, &imsg);
617 			break;
618 		case GOTD_IMSG_PACKFILE_INSTALL:
619 			err = recv_packfile_install(&client_id, &imsg);
620 			if (err == NULL)
621 				do_packfile_install = 1;
622 			break;
623 		case GOTD_IMSG_REF_UPDATES_START:
624 			err = recv_ref_updates_start(&client_id, &imsg);
625 			if (err == NULL)
626 				do_ref_updates = 1;
627 			break;
628 		case GOTD_IMSG_REF_UPDATE:
629 			err = recv_ref_update(&client_id, &imsg);
630 			if (err == NULL)
631 				do_ref_update = 1;
632 			break;
633 		default:
634 			log_debug("unexpected imsg %d", imsg.hdr.type);
635 			break;
636 		}
637 
638 		if (do_disconnect) {
639 			if (err)
640 				disconnect_on_error(client, err);
641 			else
642 				disconnect(client);
643 		} else {
644 			if (do_packfile_install)
645 				err = install_pack(client,
646 				    gotd_session.repo->path, &imsg);
647 			else if (do_ref_updates)
648 				err = begin_ref_updates(client, &imsg);
649 			else if (do_ref_update)
650 				err = update_ref(&shut, client,
651 				    gotd_session.repo->path, &imsg);
652 			if (err)
653 				log_warnx("uid %d: %s", client->euid, err->msg);
654 		}
655 		imsg_free(&imsg);
656 	}
657 done:
658 	if (!shut) {
659 		gotd_imsg_event_add(iev);
660 	} else {
661 		/* This pipe is dead. Remove its event handler */
662 		event_del(&iev->ev);
663 		event_loopexit(NULL);
664 	}
665 }
666 
667 static const struct got_error *
668 recv_capabilities(struct gotd_session_client *client, struct imsg *imsg)
669 {
670 	struct gotd_imsg_capabilities icapas;
671 	size_t datalen;
672 
673 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
674 	if (datalen != sizeof(icapas))
675 		return got_error(GOT_ERR_PRIVSEP_LEN);
676 	memcpy(&icapas, imsg->data, sizeof(icapas));
677 
678 	client->ncapa_alloc = icapas.ncapabilities;
679 	client->capabilities = calloc(client->ncapa_alloc,
680 	    sizeof(*client->capabilities));
681 	if (client->capabilities == NULL) {
682 		client->ncapa_alloc = 0;
683 		return got_error_from_errno("calloc");
684 	}
685 
686 	log_debug("expecting %zu capabilities from uid %d",
687 	    client->ncapa_alloc, client->euid);
688 	return NULL;
689 }
690 
691 static const struct got_error *
692 recv_capability(struct gotd_session_client *client, struct imsg *imsg)
693 {
694 	struct gotd_imsg_capability icapa;
695 	struct gotd_client_capability *capa;
696 	size_t datalen;
697 	char *key, *value = NULL;
698 
699 	if (client->capabilities == NULL ||
700 	    client->ncapabilities >= client->ncapa_alloc) {
701 		return got_error_msg(GOT_ERR_BAD_REQUEST,
702 		    "unexpected capability received");
703 	}
704 
705 	memset(&icapa, 0, sizeof(icapa));
706 
707 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
708 	if (datalen < sizeof(icapa))
709 		return got_error(GOT_ERR_PRIVSEP_LEN);
710 	memcpy(&icapa, imsg->data, sizeof(icapa));
711 
712 	if (datalen != sizeof(icapa) + icapa.key_len + icapa.value_len)
713 		return got_error(GOT_ERR_PRIVSEP_LEN);
714 
715 	key = strndup(imsg->data + sizeof(icapa), icapa.key_len);
716 	if (key == NULL)
717 		return got_error_from_errno("strndup");
718 	if (icapa.value_len > 0) {
719 		value = strndup(imsg->data + sizeof(icapa) + icapa.key_len,
720 		    icapa.value_len);
721 		if (value == NULL) {
722 			free(key);
723 			return got_error_from_errno("strndup");
724 		}
725 	}
726 
727 	capa = &client->capabilities[client->ncapabilities++];
728 	capa->key = key;
729 	capa->value = value;
730 
731 	if (value)
732 		log_debug("uid %d: capability %s=%s", client->euid, key, value);
733 	else
734 		log_debug("uid %d: capability %s", client->euid, key);
735 
736 	return NULL;
737 }
738 
739 static const struct got_error *
740 ensure_client_is_reading(struct gotd_session_client *client)
741 {
742 	if (client->is_writing) {
743 		return got_error_fmt(GOT_ERR_BAD_PACKET,
744 		    "uid %d made a read-request but is not reading from "
745 		    "a repository", client->euid);
746 	}
747 
748 	return NULL;
749 }
750 
751 static const struct got_error *
752 ensure_client_is_writing(struct gotd_session_client *client)
753 {
754 	if (!client->is_writing) {
755 		return got_error_fmt(GOT_ERR_BAD_PACKET,
756 		    "uid %d made a write-request but is not writing to "
757 		    "a repository", client->euid);
758 	}
759 
760 	return NULL;
761 }
762 
763 static const struct got_error *
764 forward_want(struct gotd_session_client *client, struct imsg *imsg)
765 {
766 	struct gotd_imsg_want ireq;
767 	struct gotd_imsg_want iwant;
768 	size_t datalen;
769 
770 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
771 	if (datalen != sizeof(ireq))
772 		return got_error(GOT_ERR_PRIVSEP_LEN);
773 
774 	memcpy(&ireq, imsg->data, datalen);
775 
776 	memset(&iwant, 0, sizeof(iwant));
777 	memcpy(iwant.object_id, ireq.object_id, SHA1_DIGEST_LENGTH);
778 	iwant.client_id = client->id;
779 
780 	if (gotd_imsg_compose_event(&client->repo_child_iev, GOTD_IMSG_WANT,
781 	    gotd_session.proc_id, -1, &iwant, sizeof(iwant)) == -1)
782 		return got_error_from_errno("imsg compose WANT");
783 
784 	return NULL;
785 }
786 
787 static const struct got_error *
788 forward_ref_update(struct gotd_session_client *client, struct imsg *imsg)
789 {
790 	const struct got_error *err = NULL;
791 	struct gotd_imsg_ref_update ireq;
792 	struct gotd_imsg_ref_update *iref = NULL;
793 	size_t datalen;
794 
795 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
796 	if (datalen < sizeof(ireq))
797 		return got_error(GOT_ERR_PRIVSEP_LEN);
798 	memcpy(&ireq, imsg->data, sizeof(ireq));
799 	if (datalen != sizeof(ireq) + ireq.name_len)
800 		return got_error(GOT_ERR_PRIVSEP_LEN);
801 
802 	iref = malloc(datalen);
803 	if (iref == NULL)
804 		return got_error_from_errno("malloc");
805 	memcpy(iref, imsg->data, datalen);
806 
807 	iref->client_id = client->id;
808 	if (gotd_imsg_compose_event(&client->repo_child_iev,
809 	    GOTD_IMSG_REF_UPDATE, gotd_session.proc_id, -1,
810 	    iref, datalen) == -1)
811 		err = got_error_from_errno("imsg compose REF_UPDATE");
812 	free(iref);
813 	return err;
814 }
815 
816 static const struct got_error *
817 forward_have(struct gotd_session_client *client, struct imsg *imsg)
818 {
819 	struct gotd_imsg_have ireq;
820 	struct gotd_imsg_have ihave;
821 	size_t datalen;
822 
823 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
824 	if (datalen != sizeof(ireq))
825 		return got_error(GOT_ERR_PRIVSEP_LEN);
826 
827 	memcpy(&ireq, imsg->data, datalen);
828 
829 	memset(&ihave, 0, sizeof(ihave));
830 	memcpy(ihave.object_id, ireq.object_id, SHA1_DIGEST_LENGTH);
831 	ihave.client_id = client->id;
832 
833 	if (gotd_imsg_compose_event(&client->repo_child_iev, GOTD_IMSG_HAVE,
834 	    gotd_session.proc_id, -1, &ihave, sizeof(ihave)) == -1)
835 		return got_error_from_errno("imsg compose HAVE");
836 
837 	return NULL;
838 }
839 
840 static int
841 client_has_capability(struct gotd_session_client *client, const char *capastr)
842 {
843 	struct gotd_client_capability *capa;
844 	size_t i;
845 
846 	if (client->ncapabilities == 0)
847 		return 0;
848 
849 	for (i = 0; i < client->ncapabilities; i++) {
850 		capa = &client->capabilities[i];
851 		if (strcmp(capa->key, capastr) == 0)
852 			return 1;
853 	}
854 
855 	return 0;
856 }
857 
858 static const struct got_error *
859 recv_packfile(struct gotd_session_client *client)
860 {
861 	const struct got_error *err = NULL;
862 	struct gotd_imsg_recv_packfile ipack;
863 	struct gotd_imsg_packfile_pipe ipipe;
864 	struct gotd_imsg_packidx_file ifile;
865 	char *basepath = NULL, *pack_path = NULL, *idx_path = NULL;
866 	int packfd = -1, idxfd = -1;
867 	int pipe[2] = { -1, -1 };
868 
869 	if (client->packfile_path) {
870 		return got_error_fmt(GOT_ERR_PRIVSEP_MSG,
871 		    "uid %d already has a pack file", client->euid);
872 	}
873 
874 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pipe) == -1)
875 		return got_error_from_errno("socketpair");
876 
877 	memset(&ipipe, 0, sizeof(ipipe));
878 	ipipe.client_id = client->id;
879 
880 	/* Send pack pipe end 0 to repo child process. */
881 	if (gotd_imsg_compose_event(&client->repo_child_iev,
882 	    GOTD_IMSG_PACKFILE_PIPE, gotd_session.proc_id, pipe[0],
883 	        &ipipe, sizeof(ipipe)) == -1) {
884 		err = got_error_from_errno("imsg compose PACKFILE_PIPE");
885 		pipe[0] = -1;
886 		goto done;
887 	}
888 	pipe[0] = -1;
889 
890 	/* Send pack pipe end 1 to gotsh(1) (expects just an fd, no data). */
891 	if (gotd_imsg_compose_event(&client->iev,
892 	    GOTD_IMSG_PACKFILE_PIPE, gotd_session.proc_id, pipe[1],
893 	    NULL, 0) == -1)
894 		err = got_error_from_errno("imsg compose PACKFILE_PIPE");
895 	pipe[1] = -1;
896 
897 	if (asprintf(&basepath, "%s/%s/receiving-from-uid-%d.pack",
898 	    got_repo_get_path(gotd_session.repo), GOT_OBJECTS_PACK_DIR,
899 	    client->euid) == -1) {
900 		err = got_error_from_errno("asprintf");
901 		goto done;
902 	}
903 
904 	err = got_opentemp_named_fd(&pack_path, &packfd, basepath, "");
905 	if (err)
906 		goto done;
907 	if (fchmod(packfd, GOT_DEFAULT_PACK_MODE) == -1) {
908 		err = got_error_from_errno2("fchmod", pack_path);
909 		goto done;
910 	}
911 
912 	free(basepath);
913 	if (asprintf(&basepath, "%s/%s/receiving-from-uid-%d.idx",
914 	    got_repo_get_path(gotd_session.repo), GOT_OBJECTS_PACK_DIR,
915 	    client->euid) == -1) {
916 		err = got_error_from_errno("asprintf");
917 		basepath = NULL;
918 		goto done;
919 	}
920 	err = got_opentemp_named_fd(&idx_path, &idxfd, basepath, "");
921 	if (err)
922 		goto done;
923 	if (fchmod(idxfd, GOT_DEFAULT_PACK_MODE) == -1) {
924 		err = got_error_from_errno2("fchmod", idx_path);
925 		goto done;
926 	}
927 
928 	memset(&ifile, 0, sizeof(ifile));
929 	ifile.client_id = client->id;
930 	if (gotd_imsg_compose_event(&client->repo_child_iev,
931 	    GOTD_IMSG_PACKIDX_FILE, gotd_session.proc_id,
932 	    idxfd, &ifile, sizeof(ifile)) == -1) {
933 		err = got_error_from_errno("imsg compose PACKIDX_FILE");
934 		idxfd = -1;
935 		goto done;
936 	}
937 	idxfd = -1;
938 
939 	memset(&ipack, 0, sizeof(ipack));
940 	ipack.client_id = client->id;
941 	if (client_has_capability(client, GOT_CAPA_REPORT_STATUS))
942 		ipack.report_status = 1;
943 
944 	if (gotd_imsg_compose_event(&client->repo_child_iev,
945 	    GOTD_IMSG_RECV_PACKFILE, gotd_session.proc_id, packfd,
946 	    &ipack, sizeof(ipack)) == -1) {
947 		err = got_error_from_errno("imsg compose RECV_PACKFILE");
948 		packfd = -1;
949 		goto done;
950 	}
951 	packfd = -1;
952 
953 done:
954 	free(basepath);
955 	if (pipe[0] != -1 && close(pipe[0]) == -1 && err == NULL)
956 		err = got_error_from_errno("close");
957 	if (pipe[1] != -1 && close(pipe[1]) == -1 && err == NULL)
958 		err = got_error_from_errno("close");
959 	if (packfd != -1 && close(packfd) == -1 && err == NULL)
960 		err = got_error_from_errno("close");
961 	if (idxfd != -1 && close(idxfd) == -1 && err == NULL)
962 		err = got_error_from_errno("close");
963 	if (err) {
964 		free(pack_path);
965 		free(idx_path);
966 	} else {
967 		client->packfile_path = pack_path;
968 		client->packidx_path = idx_path;
969 	}
970 	return err;
971 }
972 
973 static const struct got_error *
974 send_packfile(struct gotd_session_client *client)
975 {
976 	const struct got_error *err = NULL;
977 	struct gotd_imsg_send_packfile ipack;
978 	struct gotd_imsg_packfile_pipe ipipe;
979 	int pipe[2];
980 
981 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pipe) == -1)
982 		return got_error_from_errno("socketpair");
983 
984 	memset(&ipack, 0, sizeof(ipack));
985 	memset(&ipipe, 0, sizeof(ipipe));
986 
987 	ipack.client_id = client->id;
988 	if (client_has_capability(client, GOT_CAPA_SIDE_BAND_64K))
989 		ipack.report_progress = 1;
990 
991 	client->delta_cache_fd = got_opentempfd();
992 	if (client->delta_cache_fd == -1)
993 		return got_error_from_errno("got_opentempfd");
994 
995 	if (gotd_imsg_compose_event(&client->repo_child_iev,
996 	    GOTD_IMSG_SEND_PACKFILE, PROC_GOTD, client->delta_cache_fd,
997 	    &ipack, sizeof(ipack)) == -1) {
998 		err = got_error_from_errno("imsg compose SEND_PACKFILE");
999 		close(pipe[0]);
1000 		close(pipe[1]);
1001 		return err;
1002 	}
1003 
1004 	ipipe.client_id = client->id;
1005 
1006 	/* Send pack pipe end 0 to repo child process. */
1007 	if (gotd_imsg_compose_event(&client->repo_child_iev,
1008 	    GOTD_IMSG_PACKFILE_PIPE, PROC_GOTD,
1009 	    pipe[0], &ipipe, sizeof(ipipe)) == -1) {
1010 		err = got_error_from_errno("imsg compose PACKFILE_PIPE");
1011 		close(pipe[1]);
1012 		return err;
1013 	}
1014 
1015 	/* Send pack pipe end 1 to gotsh(1) (expects just an fd, no data). */
1016 	if (gotd_imsg_compose_event(&client->iev,
1017 	    GOTD_IMSG_PACKFILE_PIPE, PROC_GOTD, pipe[1], NULL, 0) == -1)
1018 		err = got_error_from_errno("imsg compose PACKFILE_PIPE");
1019 
1020 	return err;
1021 }
1022 
1023 static void
1024 session_dispatch_client(int fd, short events, void *arg)
1025 {
1026 	struct gotd_imsgev *iev = arg;
1027 	struct imsgbuf *ibuf = &iev->ibuf;
1028 	struct gotd_session_client *client = &gotd_session_client;
1029 	const struct got_error *err = NULL;
1030 	struct imsg imsg;
1031 	ssize_t n;
1032 
1033 	if (events & EV_WRITE) {
1034 		while (ibuf->w.queued) {
1035 			n = msgbuf_write(&ibuf->w);
1036 			if (n == -1 && errno == EPIPE) {
1037 				/*
1038 				 * The client has closed its socket.
1039 				 * This can happen when Git clients are
1040 				 * done sending pack file data.
1041 				 */
1042 				msgbuf_clear(&ibuf->w);
1043 				continue;
1044 			} else if (n == -1 && errno != EAGAIN) {
1045 				err = got_error_from_errno("imsg_flush");
1046 				disconnect_on_error(client, err);
1047 				return;
1048 			}
1049 			if (n == 0) {
1050 				/* Connection closed. */
1051 				err = got_error(GOT_ERR_EOF);
1052 				disconnect_on_error(client, err);
1053 				return;
1054 			}
1055 		}
1056 	}
1057 
1058 	if ((events & EV_READ) == 0)
1059 		return;
1060 
1061 	memset(&imsg, 0, sizeof(imsg));
1062 
1063 	while (err == NULL) {
1064 		err = gotd_imsg_recv(&imsg, ibuf, 0);
1065 		if (err) {
1066 			if (err->code == GOT_ERR_PRIVSEP_READ)
1067 				err = NULL;
1068 			else if (err->code == GOT_ERR_EOF &&
1069 			    client->state == GOTD_STATE_EXPECT_CAPABILITIES) {
1070 				/*
1071 				 * The client has closed its socket before
1072 				 * sending its capability announcement.
1073 				 * This can happen when Git clients have
1074 				 * no ref-updates to send.
1075 				 */
1076 				disconnect_on_error(client, err);
1077 				return;
1078 			}
1079 			break;
1080 		}
1081 
1082 		evtimer_del(&client->tmo);
1083 
1084 		switch (imsg.hdr.type) {
1085 		case GOTD_IMSG_CAPABILITIES:
1086 			if (client->state != GOTD_STATE_EXPECT_CAPABILITIES) {
1087 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1088 				    "unexpected capabilities received");
1089 				break;
1090 			}
1091 			log_debug("receiving capabilities from uid %d",
1092 			    client->euid);
1093 			err = recv_capabilities(client, &imsg);
1094 			break;
1095 		case GOTD_IMSG_CAPABILITY:
1096 			if (client->state != GOTD_STATE_EXPECT_CAPABILITIES) {
1097 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1098 				    "unexpected capability received");
1099 				break;
1100 			}
1101 			err = recv_capability(client, &imsg);
1102 			if (err || client->ncapabilities < client->ncapa_alloc)
1103 				break;
1104 			if (!client->is_writing) {
1105 				client->state = GOTD_STATE_EXPECT_WANT;
1106 				client->accept_flush_pkt = 1;
1107 				log_debug("uid %d: expecting want-lines",
1108 				    client->euid);
1109 			} else if (client->is_writing) {
1110 				client->state = GOTD_STATE_EXPECT_REF_UPDATE;
1111 				client->accept_flush_pkt = 1;
1112 				log_debug("uid %d: expecting ref-update-lines",
1113 				    client->euid);
1114 			} else
1115 				fatalx("client %d is both reading and writing",
1116 				    client->euid);
1117 			break;
1118 		case GOTD_IMSG_WANT:
1119 			if (client->state != GOTD_STATE_EXPECT_WANT) {
1120 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1121 				    "unexpected want-line received");
1122 				break;
1123 			}
1124 			log_debug("received want-line from uid %d",
1125 			    client->euid);
1126 			err = ensure_client_is_reading(client);
1127 			if (err)
1128 				break;
1129 			client->accept_flush_pkt = 1;
1130 			err = forward_want(client, &imsg);
1131 			break;
1132 		case GOTD_IMSG_REF_UPDATE:
1133 			if (client->state != GOTD_STATE_EXPECT_REF_UPDATE &&
1134 			    client->state !=
1135 			    GOTD_STATE_EXPECT_MORE_REF_UPDATES) {
1136 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1137 				    "unexpected ref-update-line received");
1138 				break;
1139 			}
1140 			log_debug("received ref-update-line from uid %d",
1141 			    client->euid);
1142 			err = ensure_client_is_writing(client);
1143 			if (err)
1144 				break;
1145 			err = forward_ref_update(client, &imsg);
1146 			if (err)
1147 				break;
1148 			client->state = GOTD_STATE_EXPECT_MORE_REF_UPDATES;
1149 			client->accept_flush_pkt = 1;
1150 			break;
1151 		case GOTD_IMSG_HAVE:
1152 			if (client->state != GOTD_STATE_EXPECT_HAVE) {
1153 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1154 				    "unexpected have-line received");
1155 				break;
1156 			}
1157 			log_debug("received have-line from uid %d",
1158 			    client->euid);
1159 			err = ensure_client_is_reading(client);
1160 			if (err)
1161 				break;
1162 			err = forward_have(client, &imsg);
1163 			if (err)
1164 				break;
1165 			client->accept_flush_pkt = 1;
1166 			break;
1167 		case GOTD_IMSG_FLUSH:
1168 			if (client->state == GOTD_STATE_EXPECT_WANT ||
1169 			    client->state == GOTD_STATE_EXPECT_HAVE) {
1170 				err = ensure_client_is_reading(client);
1171 				if (err)
1172 					break;
1173 			} else if (client->state ==
1174 			    GOTD_STATE_EXPECT_MORE_REF_UPDATES) {
1175 				err = ensure_client_is_writing(client);
1176 				if (err)
1177 					break;
1178 			} else if (client->state != GOTD_STATE_EXPECT_DONE) {
1179 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1180 				    "unexpected flush-pkt received");
1181 				break;
1182 			}
1183 			if (!client->accept_flush_pkt) {
1184 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1185 				    "unexpected flush-pkt received");
1186 				break;
1187 			}
1188 
1189 			/*
1190 			 * Accept just one flush packet at a time.
1191 			 * Future client state transitions will set this flag
1192 			 * again if another flush packet is expected.
1193 			 */
1194 			client->accept_flush_pkt = 0;
1195 
1196 			log_debug("received flush-pkt from uid %d",
1197 			    client->euid);
1198 			if (client->state == GOTD_STATE_EXPECT_WANT) {
1199 				client->state = GOTD_STATE_EXPECT_HAVE;
1200 				log_debug("uid %d: expecting have-lines",
1201 				    client->euid);
1202 			} else if (client->state == GOTD_STATE_EXPECT_HAVE) {
1203 				client->state = GOTD_STATE_EXPECT_DONE;
1204 				client->accept_flush_pkt = 1;
1205 				log_debug("uid %d: expecting 'done'",
1206 				    client->euid);
1207 			} else if (client->state ==
1208 			    GOTD_STATE_EXPECT_MORE_REF_UPDATES) {
1209 				client->state = GOTD_STATE_EXPECT_PACKFILE;
1210 				log_debug("uid %d: expecting packfile",
1211 				    client->euid);
1212 				err = recv_packfile(client);
1213 			} else if (client->state != GOTD_STATE_EXPECT_DONE) {
1214 				/* should not happen, see above */
1215 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1216 				    "unexpected client state");
1217 				break;
1218 			}
1219 			break;
1220 		case GOTD_IMSG_DONE:
1221 			if (client->state != GOTD_STATE_EXPECT_HAVE &&
1222 			    client->state != GOTD_STATE_EXPECT_DONE) {
1223 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1224 				    "unexpected flush-pkt received");
1225 				break;
1226 			}
1227 			log_debug("received 'done' from uid %d", client->euid);
1228 			err = ensure_client_is_reading(client);
1229 			if (err)
1230 				break;
1231 			client->state = GOTD_STATE_DONE;
1232 			client->accept_flush_pkt = 1;
1233 			err = send_packfile(client);
1234 			break;
1235 		default:
1236 			log_debug("unexpected imsg %d", imsg.hdr.type);
1237 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1238 			break;
1239 		}
1240 
1241 		imsg_free(&imsg);
1242 	}
1243 
1244 	if (err) {
1245 		if (err->code != GOT_ERR_EOF ||
1246 		    client->state != GOTD_STATE_EXPECT_PACKFILE)
1247 			disconnect_on_error(client, err);
1248 	} else {
1249 		gotd_imsg_event_add(iev);
1250 		evtimer_add(&client->tmo, &gotd_session.request_timeout);
1251 	}
1252 }
1253 
1254 static const struct got_error *
1255 list_refs_request(void)
1256 {
1257 	static const struct got_error *err;
1258 	struct gotd_session_client *client = &gotd_session_client;
1259 	struct gotd_imsgev *iev = &client->repo_child_iev;
1260 	struct gotd_imsg_list_refs_internal ilref;
1261 	int fd;
1262 
1263 	if (client->state != GOTD_STATE_EXPECT_LIST_REFS)
1264 		return got_error(GOT_ERR_PRIVSEP_MSG);
1265 
1266 	memset(&ilref, 0, sizeof(ilref));
1267 	ilref.client_id = client->id;
1268 
1269 	fd = dup(client->fd);
1270 	if (fd == -1)
1271 		return got_error_from_errno("dup");
1272 
1273 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_LIST_REFS_INTERNAL,
1274 	    gotd_session.proc_id, fd, &ilref, sizeof(ilref)) == -1) {
1275 		err = got_error_from_errno("imsg compose LIST_REFS_INTERNAL");
1276 		close(fd);
1277 		return err;
1278 	}
1279 
1280 	client->state = GOTD_STATE_EXPECT_CAPABILITIES;
1281 	log_debug("uid %d: expecting capabilities", client->euid);
1282 	return NULL;
1283 }
1284 
1285 static const struct got_error *
1286 recv_connect(struct imsg *imsg)
1287 {
1288 	struct gotd_session_client *client = &gotd_session_client;
1289 	struct gotd_imsg_connect iconnect;
1290 	size_t datalen;
1291 
1292 	if (client->state != GOTD_STATE_EXPECT_LIST_REFS)
1293 		return got_error(GOT_ERR_PRIVSEP_MSG);
1294 
1295 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1296 	if (datalen != sizeof(iconnect))
1297 		return got_error(GOT_ERR_PRIVSEP_LEN);
1298 	memcpy(&iconnect, imsg->data, sizeof(iconnect));
1299 
1300 	if (imsg->fd == -1)
1301 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
1302 
1303 	client->fd = imsg->fd;
1304 	client->euid = iconnect.euid;
1305 	client->egid = iconnect.egid;
1306 
1307 	imsg_init(&client->iev.ibuf, client->fd);
1308 	client->iev.handler = session_dispatch_client;
1309 	client->iev.events = EV_READ;
1310 	client->iev.handler_arg = NULL;
1311 	event_set(&client->iev.ev, client->iev.ibuf.fd, EV_READ,
1312 	    session_dispatch_client, &client->iev);
1313 	gotd_imsg_event_add(&client->iev);
1314 	evtimer_set(&client->tmo, gotd_request_timeout, client);
1315 
1316 	return NULL;
1317 }
1318 
1319 static const struct got_error *
1320 recv_repo_child(struct imsg *imsg)
1321 {
1322 	struct gotd_imsg_connect_repo_child ichild;
1323 	struct gotd_session_client *client = &gotd_session_client;
1324 	size_t datalen;
1325 
1326 	if (client->state != GOTD_STATE_EXPECT_LIST_REFS)
1327 		return got_error(GOT_ERR_PRIVSEP_MSG);
1328 
1329 	/* We should already have received a pipe to the listener. */
1330 	if (client->fd == -1)
1331 		return got_error(GOT_ERR_PRIVSEP_MSG);
1332 
1333 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1334 	if (datalen != sizeof(ichild))
1335 		return got_error(GOT_ERR_PRIVSEP_LEN);
1336 
1337 	memcpy(&ichild, imsg->data, sizeof(ichild));
1338 
1339 	client->id = ichild.client_id;
1340 	if (ichild.proc_id == PROC_REPO_WRITE)
1341 		client->is_writing = 1;
1342 	else if (ichild.proc_id == PROC_REPO_READ)
1343 		client->is_writing = 0;
1344 	else
1345 		return got_error_msg(GOT_ERR_PRIVSEP_MSG,
1346 		    "bad child process type");
1347 
1348 	if (imsg->fd == -1)
1349 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
1350 
1351 	imsg_init(&client->repo_child_iev.ibuf, imsg->fd);
1352 	client->repo_child_iev.handler = session_dispatch_repo_child;
1353 	client->repo_child_iev.events = EV_READ;
1354 	client->repo_child_iev.handler_arg = NULL;
1355 	event_set(&client->repo_child_iev.ev, client->repo_child_iev.ibuf.fd,
1356 	    EV_READ, session_dispatch_repo_child, &client->repo_child_iev);
1357 	gotd_imsg_event_add(&client->repo_child_iev);
1358 
1359 	/* The "recvfd" pledge promise is no longer needed. */
1360 	if (pledge("stdio rpath wpath cpath sendfd fattr flock", NULL) == -1)
1361 		fatal("pledge");
1362 
1363 	return NULL;
1364 }
1365 
1366 static void
1367 session_dispatch(int fd, short event, void *arg)
1368 {
1369 	struct gotd_imsgev *iev = arg;
1370 	struct imsgbuf *ibuf = &iev->ibuf;
1371 	struct gotd_session_client *client = &gotd_session_client;
1372 	ssize_t n;
1373 	int shut = 0;
1374 	struct imsg imsg;
1375 
1376 	if (event & EV_READ) {
1377 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1378 			fatal("imsg_read error");
1379 		if (n == 0) {
1380 			/* Connection closed. */
1381 			shut = 1;
1382 			goto done;
1383 		}
1384 	}
1385 
1386 	if (event & EV_WRITE) {
1387 		n = msgbuf_write(&ibuf->w);
1388 		if (n == -1 && errno != EAGAIN)
1389 			fatal("msgbuf_write");
1390 		if (n == 0) {
1391 			/* Connection closed. */
1392 			shut = 1;
1393 			goto done;
1394 		}
1395 	}
1396 
1397 	for (;;) {
1398 		const struct got_error *err = NULL;
1399 		uint32_t client_id = 0;
1400 		int do_disconnect = 0, do_list_refs = 0;
1401 
1402 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1403 			fatal("%s: imsg_get error", __func__);
1404 		if (n == 0)	/* No more messages. */
1405 			break;
1406 
1407 		switch (imsg.hdr.type) {
1408 		case GOTD_IMSG_ERROR:
1409 			do_disconnect = 1;
1410 			err = gotd_imsg_recv_error(&client_id, &imsg);
1411 			break;
1412 		case GOTD_IMSG_CONNECT:
1413 			err = recv_connect(&imsg);
1414 			break;
1415 		case GOTD_IMSG_DISCONNECT:
1416 			do_disconnect = 1;
1417 			break;
1418 		case GOTD_IMSG_CONNECT_REPO_CHILD:
1419 			err = recv_repo_child(&imsg);
1420 			if (err)
1421 				break;
1422 			do_list_refs = 1;
1423 			break;
1424 		default:
1425 			log_debug("unexpected imsg %d", imsg.hdr.type);
1426 			break;
1427 		}
1428 		imsg_free(&imsg);
1429 
1430 		if (do_disconnect) {
1431 			if (err)
1432 				disconnect_on_error(client, err);
1433 			else
1434 				disconnect(client);
1435 		} else if (do_list_refs)
1436 			err = list_refs_request();
1437 
1438 		if (err)
1439 			log_warnx("uid %d: %s", client->euid, err->msg);
1440 	}
1441 done:
1442 	if (!shut) {
1443 		gotd_imsg_event_add(iev);
1444 	} else {
1445 		/* This pipe is dead. Remove its event handler */
1446 		event_del(&iev->ev);
1447 		event_loopexit(NULL);
1448 	}
1449 }
1450 
1451 void
1452 session_main(const char *title, const char *repo_path,
1453     int *pack_fds, int *temp_fds, struct timeval *request_timeout,
1454     enum gotd_procid proc_id)
1455 {
1456 	const struct got_error *err = NULL;
1457 	struct event evsigint, evsigterm, evsighup, evsigusr1;
1458 
1459 	gotd_session.title = title;
1460 	gotd_session.pid = getpid();
1461 	gotd_session.pack_fds = pack_fds;
1462 	gotd_session.temp_fds = temp_fds;
1463 	memcpy(&gotd_session.request_timeout, request_timeout,
1464 	    sizeof(gotd_session.request_timeout));
1465 	gotd_session.proc_id = proc_id;
1466 
1467 	err = got_repo_open(&gotd_session.repo, repo_path, NULL, pack_fds);
1468 	if (err)
1469 		goto done;
1470 	if (!got_repo_is_bare(gotd_session.repo)) {
1471 		err = got_error_msg(GOT_ERR_NOT_GIT_REPO,
1472 		    "bare git repository required");
1473 		goto done;
1474 	}
1475 
1476 	got_repo_temp_fds_set(gotd_session.repo, temp_fds);
1477 
1478 	signal_set(&evsigint, SIGINT, gotd_session_sighdlr, NULL);
1479 	signal_set(&evsigterm, SIGTERM, gotd_session_sighdlr, NULL);
1480 	signal_set(&evsighup, SIGHUP, gotd_session_sighdlr, NULL);
1481 	signal_set(&evsigusr1, SIGUSR1, gotd_session_sighdlr, NULL);
1482 	signal(SIGPIPE, SIG_IGN);
1483 
1484 	signal_add(&evsigint, NULL);
1485 	signal_add(&evsigterm, NULL);
1486 	signal_add(&evsighup, NULL);
1487 	signal_add(&evsigusr1, NULL);
1488 
1489 	gotd_session_client.state = GOTD_STATE_EXPECT_LIST_REFS;
1490 	gotd_session_client.fd = -1;
1491 	gotd_session_client.nref_updates = -1;
1492 	gotd_session_client.delta_cache_fd = -1;
1493 	gotd_session_client.accept_flush_pkt = 1;
1494 
1495 	imsg_init(&gotd_session.parent_iev.ibuf, GOTD_FILENO_MSG_PIPE);
1496 	gotd_session.parent_iev.handler = session_dispatch;
1497 	gotd_session.parent_iev.events = EV_READ;
1498 	gotd_session.parent_iev.handler_arg = NULL;
1499 	event_set(&gotd_session.parent_iev.ev, gotd_session.parent_iev.ibuf.fd,
1500 	    EV_READ, session_dispatch, &gotd_session.parent_iev);
1501 	if (gotd_imsg_compose_event(&gotd_session.parent_iev,
1502 	    GOTD_IMSG_CLIENT_SESSION_READY, gotd_session.proc_id,
1503 	    -1, NULL, 0) == -1) {
1504 		err = got_error_from_errno("imsg compose CLIENT_SESSION_READY");
1505 		goto done;
1506 	}
1507 
1508 	event_dispatch();
1509 done:
1510 	if (err)
1511 		log_warnx("%s: %s", title, err->msg);
1512 	gotd_session_shutdown();
1513 }
1514 
1515 void
1516 gotd_session_shutdown(void)
1517 {
1518 	log_debug("shutting down");
1519 	if (gotd_session.repo)
1520 		got_repo_close(gotd_session.repo);
1521 	got_repo_pack_fds_close(gotd_session.pack_fds);
1522 	got_repo_temp_fds_close(gotd_session.temp_fds);
1523 	exit(0);
1524 }