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Date:: Thu Feb 23 08:41:30 2023 UTC
Message:: rename lib/sha1.c to lib/hash.c It will soon grow functions to deal with sha256 too. stsp@ agrees.
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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.h"
55 
56 
57 static struct gotd_session {
58 	pid_t pid;
59 	const char *title;
60 	struct got_repository *repo;
61 	int *pack_fds;
62 	int *temp_fds;
63 	struct gotd_imsgev parent_iev;
64 	struct timeval request_timeout;
65 } gotd_session;
66 
67 static struct gotd_session_client {
68 	enum gotd_session_state		 state;
69 	int				 is_writing;
70 	struct gotd_client_capability	*capabilities;
71 	size_t				 ncapa_alloc;
72 	size_t				 ncapabilities;
73 	uint32_t			 id;
74 	int				 fd;
75 	int				 delta_cache_fd;
76 	struct gotd_imsgev		 iev;
77 	struct gotd_imsgev		 repo_child_iev;
78 	struct event			 tmo;
79 	uid_t				 euid;
80 	gid_t				 egid;
81 	char				*packfile_path;
82 	char				*packidx_path;
83 	int				 nref_updates;
84 	int				 accept_flush_pkt;
85 } gotd_session_client;
86 
87 void gotd_session_sighdlr(int sig, short event, void *arg);
88 static void gotd_session_shutdown(void);
89 
90 static void
91 disconnect(struct gotd_session_client *client)
92 {
93 	log_debug("uid %d: disconnecting", client->euid);
94 
95 	if (gotd_imsg_compose_event(&gotd_session.parent_iev,
96 	    GOTD_IMSG_DISCONNECT, PROC_SESSION, -1, NULL, 0) == -1)
97 		log_warn("imsg compose DISCONNECT");
98 
99 	imsg_clear(&client->repo_child_iev.ibuf);
100 	event_del(&client->repo_child_iev.ev);
101 	evtimer_del(&client->tmo);
102 	close(client->fd);
103 	if (client->delta_cache_fd != -1)
104 		close(client->delta_cache_fd);
105 	if (client->packfile_path) {
106 		if (unlink(client->packfile_path) == -1 && errno != ENOENT)
107 			log_warn("unlink %s: ", client->packfile_path);
108 		free(client->packfile_path);
109 	}
110 	if (client->packidx_path) {
111 		if (unlink(client->packidx_path) == -1 && errno != ENOENT)
112 			log_warn("unlink %s: ", client->packidx_path);
113 		free(client->packidx_path);
114 	}
115 	free(client->capabilities);
116 
117 	gotd_session_shutdown();
118 }
119 
120 static void
121 disconnect_on_error(struct gotd_session_client *client,
122     const struct got_error *err)
123 {
124 	struct imsgbuf ibuf;
125 
126 	log_warnx("uid %d: %s", client->euid, err->msg);
127 	if (err->code != GOT_ERR_EOF) {
128 		imsg_init(&ibuf, client->fd);
129 		gotd_imsg_send_error(&ibuf, 0, PROC_SESSION, err);
130 		imsg_clear(&ibuf);
131 	}
132 
133 	disconnect(client);
134 }
135 
136 static void
137 gotd_request_timeout(int fd, short events, void *arg)
138 {
139 	struct gotd_session_client *client = arg;
140 
141 	log_debug("disconnecting uid %d due to timeout", client->euid);
142 	disconnect(client);
143 }
144 
145 void
146 gotd_session_sighdlr(int sig, short event, void *arg)
147 {
148 	/*
149 	 * Normal signal handler rules don't apply because libevent
150 	 * decouples for us.
151 	 */
152 
153 	switch (sig) {
154 	case SIGHUP:
155 		log_info("%s: ignoring SIGHUP", __func__);
156 		break;
157 	case SIGUSR1:
158 		log_info("%s: ignoring SIGUSR1", __func__);
159 		break;
160 	case SIGTERM:
161 	case SIGINT:
162 		gotd_session_shutdown();
163 		/* NOTREACHED */
164 		break;
165 	default:
166 		fatalx("unexpected signal");
167 	}
168 }
169 
170 static const struct got_error *
171 recv_packfile_done(uint32_t *client_id, struct imsg *imsg)
172 {
173 	struct gotd_imsg_packfile_done idone;
174 	size_t datalen;
175 
176 	log_debug("packfile-done received");
177 
178 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
179 	if (datalen != sizeof(idone))
180 		return got_error(GOT_ERR_PRIVSEP_LEN);
181 	memcpy(&idone, imsg->data, sizeof(idone));
182 
183 	*client_id = idone.client_id;
184 	return NULL;
185 }
186 
187 static const struct got_error *
188 recv_packfile_install(uint32_t *client_id, struct imsg *imsg)
189 {
190 	struct gotd_imsg_packfile_install inst;
191 	size_t datalen;
192 
193 	log_debug("packfile-install received");
194 
195 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
196 	if (datalen != sizeof(inst))
197 		return got_error(GOT_ERR_PRIVSEP_LEN);
198 	memcpy(&inst, imsg->data, sizeof(inst));
199 
200 	*client_id = inst.client_id;
201 	return NULL;
202 }
203 
204 static const struct got_error *
205 recv_ref_updates_start(uint32_t *client_id, struct imsg *imsg)
206 {
207 	struct gotd_imsg_ref_updates_start istart;
208 	size_t datalen;
209 
210 	log_debug("ref-updates-start received");
211 
212 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
213 	if (datalen != sizeof(istart))
214 		return got_error(GOT_ERR_PRIVSEP_LEN);
215 	memcpy(&istart, imsg->data, sizeof(istart));
216 
217 	*client_id = istart.client_id;
218 	return NULL;
219 }
220 
221 static const struct got_error *
222 recv_ref_update(uint32_t *client_id, struct imsg *imsg)
223 {
224 	struct gotd_imsg_ref_update iref;
225 	size_t datalen;
226 
227 	log_debug("ref-update received");
228 
229 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
230 	if (datalen < sizeof(iref))
231 		return got_error(GOT_ERR_PRIVSEP_LEN);
232 	memcpy(&iref, imsg->data, sizeof(iref));
233 
234 	*client_id = iref.client_id;
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 	iok.client_id = client->id;
249 	memcpy(iok.old_id, iref->old_id, SHA1_DIGEST_LENGTH);
250 	memcpy(iok.new_id, iref->new_id, SHA1_DIGEST_LENGTH);
251 	iok.name_len = strlen(refname);
252 
253 	len = sizeof(iok) + iok.name_len;
254 	wbuf = imsg_create(&iev->ibuf, GOTD_IMSG_REF_UPDATE_OK,
255 	    PROC_SESSION, gotd_session.pid, len);
256 	if (wbuf == NULL)
257 		return got_error_from_errno("imsg_create REF_UPDATE_OK");
258 
259 	if (imsg_add(wbuf, &iok, sizeof(iok)) == -1)
260 		return got_error_from_errno("imsg_add REF_UPDATE_OK");
261 	if (imsg_add(wbuf, refname, iok.name_len) == -1)
262 		return got_error_from_errno("imsg_add REF_UPDATE_OK");
263 
264 	wbuf->fd = -1;
265 	imsg_close(&iev->ibuf, wbuf);
266 	gotd_imsg_event_add(iev);
267 	return NULL;
268 }
269 
270 static void
271 send_refs_updated(struct gotd_session_client *client)
272 {
273 	if (gotd_imsg_compose_event(&client->iev, GOTD_IMSG_REFS_UPDATED,
274 	    PROC_SESSION, -1, NULL, 0) == -1)
275 		log_warn("imsg compose REFS_UPDATED");
276 }
277 
278 static const struct got_error *
279 send_ref_update_ng(struct gotd_session_client *client,
280     struct gotd_imsg_ref_update *iref, const char *refname,
281     const char *reason)
282 {
283 	const struct got_error *ng_err;
284 	struct gotd_imsg_ref_update_ng ing;
285 	struct gotd_imsgev *iev = &client->iev;
286 	struct ibuf *wbuf;
287 	size_t len;
288 
289 	memset(&ing, 0, sizeof(ing));
290 	ing.client_id = client->id;
291 	memcpy(ing.old_id, iref->old_id, SHA1_DIGEST_LENGTH);
292 	memcpy(ing.new_id, iref->new_id, SHA1_DIGEST_LENGTH);
293 	ing.name_len = strlen(refname);
294 
295 	ng_err = got_error_fmt(GOT_ERR_REF_BUSY, "%s", reason);
296 	ing.reason_len = strlen(ng_err->msg);
297 
298 	len = sizeof(ing) + ing.name_len + ing.reason_len;
299 	wbuf = imsg_create(&iev->ibuf, GOTD_IMSG_REF_UPDATE_NG,
300 	    PROC_SESSION, gotd_session.pid, len);
301 	if (wbuf == NULL)
302 		return got_error_from_errno("imsg_create REF_UPDATE_NG");
303 
304 	if (imsg_add(wbuf, &ing, sizeof(ing)) == -1)
305 		return got_error_from_errno("imsg_add REF_UPDATE_NG");
306 	if (imsg_add(wbuf, refname, ing.name_len) == -1)
307 		return got_error_from_errno("imsg_add REF_UPDATE_NG");
308 	if (imsg_add(wbuf, ng_err->msg, ing.reason_len) == -1)
309 		return got_error_from_errno("imsg_add REF_UPDATE_NG");
310 
311 	wbuf->fd = -1;
312 	imsg_close(&iev->ibuf, wbuf);
313 	gotd_imsg_event_add(iev);
314 	return NULL;
315 }
316 
317 static const struct got_error *
318 install_pack(struct gotd_session_client *client, const char *repo_path,
319     struct imsg *imsg)
320 {
321 	const struct got_error *err = NULL;
322 	struct gotd_imsg_packfile_install inst;
323 	char hex[SHA1_DIGEST_STRING_LENGTH];
324 	size_t datalen;
325 	char *packfile_path = NULL, *packidx_path = NULL;
326 
327 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
328 	if (datalen != sizeof(inst))
329 		return got_error(GOT_ERR_PRIVSEP_LEN);
330 	memcpy(&inst, imsg->data, sizeof(inst));
331 
332 	if (client->packfile_path == NULL)
333 		return got_error_msg(GOT_ERR_BAD_REQUEST,
334 		    "client has no pack file");
335 	if (client->packidx_path == NULL)
336 		return got_error_msg(GOT_ERR_BAD_REQUEST,
337 		    "client has no pack file index");
338 
339 	if (got_sha1_digest_to_str(inst.pack_sha1, hex, sizeof(hex)) == NULL)
340 		return got_error_msg(GOT_ERR_NO_SPACE,
341 		    "could not convert pack file SHA1 to hex");
342 
343 	if (asprintf(&packfile_path, "/%s/%s/pack-%s.pack",
344 	    repo_path, GOT_OBJECTS_PACK_DIR, hex) == -1) {
345 		err = got_error_from_errno("asprintf");
346 		goto done;
347 	}
348 
349 	if (asprintf(&packidx_path, "/%s/%s/pack-%s.idx",
350 	    repo_path, GOT_OBJECTS_PACK_DIR, hex) == -1) {
351 		err = got_error_from_errno("asprintf");
352 		goto done;
353 	}
354 
355 	if (rename(client->packfile_path, packfile_path) == -1) {
356 		err = got_error_from_errno3("rename", client->packfile_path,
357 		    packfile_path);
358 		goto done;
359 	}
360 
361 	free(client->packfile_path);
362 	client->packfile_path = NULL;
363 
364 	if (rename(client->packidx_path, packidx_path) == -1) {
365 		err = got_error_from_errno3("rename", client->packidx_path,
366 		    packidx_path);
367 		goto done;
368 	}
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 update_ref(int *shut, struct gotd_session_client *client,
401     const char *repo_path, struct imsg *imsg)
402 {
403 	const struct got_error *err = NULL;
404 	struct got_repository *repo = NULL;
405 	struct got_reference *ref = NULL;
406 	struct gotd_imsg_ref_update iref;
407 	struct got_object_id old_id, new_id;
408 	struct got_object_id *id = NULL;
409 	struct got_object *obj = NULL;
410 	char *refname = NULL;
411 	size_t datalen;
412 	int locked = 0;
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_error_fmt(GOT_ERR_REF_BUSY,
455 			    "%s has been created by someone else "
456 			    "while transaction was in progress",
457 			    got_ref_get_name(ref));
458 			goto done;
459 		}
460 	} else if (iref.delete_ref) {
461 		err = got_ref_open(&ref, repo, refname, 1 /* lock */);
462 		if (err)
463 			goto done;
464 		locked = 1;
465 
466 		err = got_ref_resolve(&id, repo, ref);
467 		if (err)
468 			goto done;
469 
470 		if (got_object_id_cmp(id, &old_id) != 0) {
471 			err = got_error_fmt(GOT_ERR_REF_BUSY,
472 			    "%s has been modified by someone else "
473 			    "while transaction was in progress",
474 			    got_ref_get_name(ref));
475 			goto done;
476 		}
477 
478 		err = got_ref_delete(ref, repo);
479 		if (err)
480 			goto done;
481 
482 		free(id);
483 		id = NULL;
484 	} else {
485 		err = got_ref_open(&ref, repo, refname, 1 /* lock */);
486 		if (err)
487 			goto done;
488 		locked = 1;
489 
490 		err = got_ref_resolve(&id, repo, ref);
491 		if (err)
492 			goto done;
493 
494 		if (got_object_id_cmp(id, &old_id) != 0) {
495 			err = got_error_fmt(GOT_ERR_REF_BUSY,
496 			    "%s has been modified by someone else "
497 			    "while transaction was in progress",
498 			    got_ref_get_name(ref));
499 			goto done;
500 		}
501 
502 		err = got_ref_change_ref(ref, &new_id);
503 		if (err)
504 			goto done;
505 
506 		err = got_ref_write(ref, repo);
507 		if (err)
508 			goto done;
509 
510 		free(id);
511 		id = NULL;
512 	}
513 done:
514 	if (err) {
515 		if (err->code == GOT_ERR_LOCKFILE_TIMEOUT) {
516 			err = got_error_fmt(GOT_ERR_LOCKFILE_TIMEOUT,
517 			    "could not acquire exclusive file lock for %s",
518 			    refname);
519 		}
520 		send_ref_update_ng(client, &iref, refname, err->msg);
521 	} else
522 		send_ref_update_ok(client, &iref, refname);
523 
524 	if (client->nref_updates > 0) {
525 		client->nref_updates--;
526 		if (client->nref_updates == 0) {
527 			send_refs_updated(client);
528 			*shut = 1;
529 		}
530 
531 	}
532 	if (locked) {
533 		const struct got_error *unlock_err;
534 		unlock_err = got_ref_unlock(ref);
535 		if (unlock_err && err == NULL)
536 			err = unlock_err;
537 	}
538 	if (ref)
539 		got_ref_close(ref);
540 	if (obj)
541 		got_object_close(obj);
542 	if (repo)
543 		got_repo_close(repo);
544 	free(refname);
545 	free(id);
546 	return err;
547 }
548 
549 static void
550 session_dispatch_repo_child(int fd, short event, void *arg)
551 {
552 	struct gotd_imsgev *iev = arg;
553 	struct imsgbuf *ibuf = &iev->ibuf;
554 	struct gotd_session_client *client = &gotd_session_client;
555 	ssize_t n;
556 	int shut = 0;
557 	struct imsg imsg;
558 
559 	if (event & EV_READ) {
560 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
561 			fatal("imsg_read error");
562 		if (n == 0) {
563 			/* Connection closed. */
564 			shut = 1;
565 			goto done;
566 		}
567 	}
568 
569 	if (event & EV_WRITE) {
570 		n = msgbuf_write(&ibuf->w);
571 		if (n == -1 && errno != EAGAIN)
572 			fatal("msgbuf_write");
573 		if (n == 0) {
574 			/* Connection closed. */
575 			shut = 1;
576 			goto done;
577 		}
578 	}
579 
580 	for (;;) {
581 		const struct got_error *err = NULL;
582 		uint32_t client_id = 0;
583 		int do_disconnect = 0;
584 		int do_ref_updates = 0, do_ref_update = 0;
585 		int do_packfile_install = 0;
586 
587 		if ((n = imsg_get(ibuf, &imsg)) == -1)
588 			fatal("%s: imsg_get error", __func__);
589 		if (n == 0)	/* No more messages. */
590 			break;
591 
592 		switch (imsg.hdr.type) {
593 		case GOTD_IMSG_ERROR:
594 			do_disconnect = 1;
595 			err = gotd_imsg_recv_error(&client_id, &imsg);
596 			break;
597 		case GOTD_IMSG_PACKFILE_DONE:
598 			do_disconnect = 1;
599 			err = recv_packfile_done(&client_id, &imsg);
600 			break;
601 		case GOTD_IMSG_PACKFILE_INSTALL:
602 			err = recv_packfile_install(&client_id, &imsg);
603 			if (err == NULL)
604 				do_packfile_install = 1;
605 			break;
606 		case GOTD_IMSG_REF_UPDATES_START:
607 			err = recv_ref_updates_start(&client_id, &imsg);
608 			if (err == NULL)
609 				do_ref_updates = 1;
610 			break;
611 		case GOTD_IMSG_REF_UPDATE:
612 			err = recv_ref_update(&client_id, &imsg);
613 			if (err == NULL)
614 				do_ref_update = 1;
615 			break;
616 		default:
617 			log_debug("unexpected imsg %d", imsg.hdr.type);
618 			break;
619 		}
620 
621 		if (do_disconnect) {
622 			if (err)
623 				disconnect_on_error(client, err);
624 			else
625 				disconnect(client);
626 		} else {
627 			if (do_packfile_install)
628 				err = install_pack(client,
629 				    gotd_session.repo->path, &imsg);
630 			else if (do_ref_updates)
631 				err = begin_ref_updates(client, &imsg);
632 			else if (do_ref_update)
633 				err = update_ref(&shut, client,
634 				    gotd_session.repo->path, &imsg);
635 			if (err)
636 				log_warnx("uid %d: %s", client->euid, err->msg);
637 		}
638 		imsg_free(&imsg);
639 	}
640 done:
641 	if (!shut) {
642 		gotd_imsg_event_add(iev);
643 	} else {
644 		/* This pipe is dead. Remove its event handler */
645 		event_del(&iev->ev);
646 		event_loopexit(NULL);
647 	}
648 }
649 
650 static const struct got_error *
651 recv_capabilities(struct gotd_session_client *client, struct imsg *imsg)
652 {
653 	struct gotd_imsg_capabilities icapas;
654 	size_t datalen;
655 
656 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
657 	if (datalen != sizeof(icapas))
658 		return got_error(GOT_ERR_PRIVSEP_LEN);
659 	memcpy(&icapas, imsg->data, sizeof(icapas));
660 
661 	client->ncapa_alloc = icapas.ncapabilities;
662 	client->capabilities = calloc(client->ncapa_alloc,
663 	    sizeof(*client->capabilities));
664 	if (client->capabilities == NULL) {
665 		client->ncapa_alloc = 0;
666 		return got_error_from_errno("calloc");
667 	}
668 
669 	log_debug("expecting %zu capabilities from uid %d",
670 	    client->ncapa_alloc, client->euid);
671 	return NULL;
672 }
673 
674 static const struct got_error *
675 recv_capability(struct gotd_session_client *client, struct imsg *imsg)
676 {
677 	struct gotd_imsg_capability icapa;
678 	struct gotd_client_capability *capa;
679 	size_t datalen;
680 	char *key, *value = NULL;
681 
682 	if (client->capabilities == NULL ||
683 	    client->ncapabilities >= client->ncapa_alloc) {
684 		return got_error_msg(GOT_ERR_BAD_REQUEST,
685 		    "unexpected capability received");
686 	}
687 
688 	memset(&icapa, 0, sizeof(icapa));
689 
690 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
691 	if (datalen < sizeof(icapa))
692 		return got_error(GOT_ERR_PRIVSEP_LEN);
693 	memcpy(&icapa, imsg->data, sizeof(icapa));
694 
695 	if (datalen != sizeof(icapa) + icapa.key_len + icapa.value_len)
696 		return got_error(GOT_ERR_PRIVSEP_LEN);
697 
698 	key = strndup(imsg->data + sizeof(icapa), icapa.key_len);
699 	if (key == NULL)
700 		return got_error_from_errno("strndup");
701 	if (icapa.value_len > 0) {
702 		value = strndup(imsg->data + sizeof(icapa) + icapa.key_len,
703 		    icapa.value_len);
704 		if (value == NULL) {
705 			free(key);
706 			return got_error_from_errno("strndup");
707 		}
708 	}
709 
710 	capa = &client->capabilities[client->ncapabilities++];
711 	capa->key = key;
712 	capa->value = value;
713 
714 	if (value)
715 		log_debug("uid %d: capability %s=%s", client->euid, key, value);
716 	else
717 		log_debug("uid %d: capability %s", client->euid, key);
718 
719 	return NULL;
720 }
721 
722 static const struct got_error *
723 ensure_client_is_reading(struct gotd_session_client *client)
724 {
725 	if (client->is_writing) {
726 		return got_error_fmt(GOT_ERR_BAD_PACKET,
727 		    "uid %d made a read-request but is not reading from "
728 		    "a repository", client->euid);
729 	}
730 
731 	return NULL;
732 }
733 
734 static const struct got_error *
735 ensure_client_is_writing(struct gotd_session_client *client)
736 {
737 	if (!client->is_writing) {
738 		return got_error_fmt(GOT_ERR_BAD_PACKET,
739 		    "uid %d made a write-request but is not writing to "
740 		    "a repository", client->euid);
741 	}
742 
743 	return NULL;
744 }
745 
746 static const struct got_error *
747 forward_want(struct gotd_session_client *client, struct imsg *imsg)
748 {
749 	struct gotd_imsg_want ireq;
750 	struct gotd_imsg_want iwant;
751 	size_t datalen;
752 
753 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
754 	if (datalen != sizeof(ireq))
755 		return got_error(GOT_ERR_PRIVSEP_LEN);
756 
757 	memcpy(&ireq, imsg->data, datalen);
758 
759 	memset(&iwant, 0, sizeof(iwant));
760 	memcpy(iwant.object_id, ireq.object_id, SHA1_DIGEST_LENGTH);
761 	iwant.client_id = client->id;
762 
763 	if (gotd_imsg_compose_event(&client->repo_child_iev, GOTD_IMSG_WANT,
764 	    PROC_SESSION, -1, &iwant, sizeof(iwant)) == -1)
765 		return got_error_from_errno("imsg compose WANT");
766 
767 	return NULL;
768 }
769 
770 static const struct got_error *
771 forward_ref_update(struct gotd_session_client *client, struct imsg *imsg)
772 {
773 	const struct got_error *err = NULL;
774 	struct gotd_imsg_ref_update ireq;
775 	struct gotd_imsg_ref_update *iref = NULL;
776 	size_t datalen;
777 
778 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
779 	if (datalen < sizeof(ireq))
780 		return got_error(GOT_ERR_PRIVSEP_LEN);
781 	memcpy(&ireq, imsg->data, sizeof(ireq));
782 	if (datalen != sizeof(ireq) + ireq.name_len)
783 		return got_error(GOT_ERR_PRIVSEP_LEN);
784 
785 	iref = malloc(datalen);
786 	if (iref == NULL)
787 		return got_error_from_errno("malloc");
788 	memcpy(iref, imsg->data, datalen);
789 
790 	iref->client_id = client->id;
791 	if (gotd_imsg_compose_event(&client->repo_child_iev,
792 	    GOTD_IMSG_REF_UPDATE, PROC_SESSION, -1, iref, datalen) == -1)
793 		err = got_error_from_errno("imsg compose REF_UPDATE");
794 	free(iref);
795 	return err;
796 }
797 
798 static const struct got_error *
799 forward_have(struct gotd_session_client *client, struct imsg *imsg)
800 {
801 	struct gotd_imsg_have ireq;
802 	struct gotd_imsg_have ihave;
803 	size_t datalen;
804 
805 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
806 	if (datalen != sizeof(ireq))
807 		return got_error(GOT_ERR_PRIVSEP_LEN);
808 
809 	memcpy(&ireq, imsg->data, datalen);
810 
811 	memset(&ihave, 0, sizeof(ihave));
812 	memcpy(ihave.object_id, ireq.object_id, SHA1_DIGEST_LENGTH);
813 	ihave.client_id = client->id;
814 
815 	if (gotd_imsg_compose_event(&client->repo_child_iev, GOTD_IMSG_HAVE,
816 	    PROC_SESSION, -1, &ihave, sizeof(ihave)) == -1)
817 		return got_error_from_errno("imsg compose HAVE");
818 
819 	return NULL;
820 }
821 
822 static int
823 client_has_capability(struct gotd_session_client *client, const char *capastr)
824 {
825 	struct gotd_client_capability *capa;
826 	size_t i;
827 
828 	if (client->ncapabilities == 0)
829 		return 0;
830 
831 	for (i = 0; i < client->ncapabilities; i++) {
832 		capa = &client->capabilities[i];
833 		if (strcmp(capa->key, capastr) == 0)
834 			return 1;
835 	}
836 
837 	return 0;
838 }
839 
840 static const struct got_error *
841 recv_packfile(struct gotd_session_client *client)
842 {
843 	const struct got_error *err = NULL;
844 	struct gotd_imsg_recv_packfile ipack;
845 	struct gotd_imsg_packfile_pipe ipipe;
846 	struct gotd_imsg_packidx_file ifile;
847 	char *basepath = NULL, *pack_path = NULL, *idx_path = NULL;
848 	int packfd = -1, idxfd = -1;
849 	int pipe[2] = { -1, -1 };
850 
851 	if (client->packfile_path) {
852 		return got_error_fmt(GOT_ERR_PRIVSEP_MSG,
853 		    "uid %d already has a pack file", client->euid);
854 	}
855 
856 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pipe) == -1)
857 		return got_error_from_errno("socketpair");
858 
859 	memset(&ipipe, 0, sizeof(ipipe));
860 	ipipe.client_id = client->id;
861 
862 	/* Send pack pipe end 0 to repo child process. */
863 	if (gotd_imsg_compose_event(&client->repo_child_iev,
864 	    GOTD_IMSG_PACKFILE_PIPE, PROC_SESSION, pipe[0],
865 	        &ipipe, sizeof(ipipe)) == -1) {
866 		err = got_error_from_errno("imsg compose PACKFILE_PIPE");
867 		pipe[0] = -1;
868 		goto done;
869 	}
870 	pipe[0] = -1;
871 
872 	/* Send pack pipe end 1 to gotsh(1) (expects just an fd, no data). */
873 	if (gotd_imsg_compose_event(&client->iev,
874 	    GOTD_IMSG_PACKFILE_PIPE, PROC_SESSION, pipe[1], NULL, 0) == -1)
875 		err = got_error_from_errno("imsg compose PACKFILE_PIPE");
876 	pipe[1] = -1;
877 
878 	if (asprintf(&basepath, "%s/%s/receiving-from-uid-%d.pack",
879 	    got_repo_get_path(gotd_session.repo), GOT_OBJECTS_PACK_DIR,
880 	    client->euid) == -1) {
881 		err = got_error_from_errno("asprintf");
882 		goto done;
883 	}
884 
885 	err = got_opentemp_named_fd(&pack_path, &packfd, basepath, "");
886 	if (err)
887 		goto done;
888 	if (fchmod(packfd, GOT_DEFAULT_PACK_MODE) == -1) {
889 		err = got_error_from_errno2("fchmod", pack_path);
890 		goto done;
891 	}
892 
893 	free(basepath);
894 	if (asprintf(&basepath, "%s/%s/receiving-from-uid-%d.idx",
895 	    got_repo_get_path(gotd_session.repo), GOT_OBJECTS_PACK_DIR,
896 	    client->euid) == -1) {
897 		err = got_error_from_errno("asprintf");
898 		basepath = NULL;
899 		goto done;
900 	}
901 	err = got_opentemp_named_fd(&idx_path, &idxfd, basepath, "");
902 	if (err)
903 		goto done;
904 	if (fchmod(idxfd, GOT_DEFAULT_PACK_MODE) == -1) {
905 		err = got_error_from_errno2("fchmod", idx_path);
906 		goto done;
907 	}
908 
909 	memset(&ifile, 0, sizeof(ifile));
910 	ifile.client_id = client->id;
911 	if (gotd_imsg_compose_event(&client->repo_child_iev,
912 	    GOTD_IMSG_PACKIDX_FILE, PROC_SESSION,
913 	    idxfd, &ifile, sizeof(ifile)) == -1) {
914 		err = got_error_from_errno("imsg compose PACKIDX_FILE");
915 		idxfd = -1;
916 		goto done;
917 	}
918 	idxfd = -1;
919 
920 	memset(&ipack, 0, sizeof(ipack));
921 	ipack.client_id = client->id;
922 	if (client_has_capability(client, GOT_CAPA_REPORT_STATUS))
923 		ipack.report_status = 1;
924 
925 	if (gotd_imsg_compose_event(&client->repo_child_iev,
926 	    GOTD_IMSG_RECV_PACKFILE, PROC_SESSION, packfd,
927 	    &ipack, sizeof(ipack)) == -1) {
928 		err = got_error_from_errno("imsg compose RECV_PACKFILE");
929 		packfd = -1;
930 		goto done;
931 	}
932 	packfd = -1;
933 
934 done:
935 	free(basepath);
936 	if (pipe[0] != -1 && close(pipe[0]) == -1 && err == NULL)
937 		err = got_error_from_errno("close");
938 	if (pipe[1] != -1 && close(pipe[1]) == -1 && err == NULL)
939 		err = got_error_from_errno("close");
940 	if (packfd != -1 && close(packfd) == -1 && err == NULL)
941 		err = got_error_from_errno("close");
942 	if (idxfd != -1 && close(idxfd) == -1 && err == NULL)
943 		err = got_error_from_errno("close");
944 	if (err) {
945 		free(pack_path);
946 		free(idx_path);
947 	} else {
948 		client->packfile_path = pack_path;
949 		client->packidx_path = idx_path;
950 	}
951 	return err;
952 }
953 
954 static const struct got_error *
955 send_packfile(struct gotd_session_client *client)
956 {
957 	const struct got_error *err = NULL;
958 	struct gotd_imsg_send_packfile ipack;
959 	struct gotd_imsg_packfile_pipe ipipe;
960 	int pipe[2];
961 
962 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pipe) == -1)
963 		return got_error_from_errno("socketpair");
964 
965 	memset(&ipack, 0, sizeof(ipack));
966 	memset(&ipipe, 0, sizeof(ipipe));
967 
968 	ipack.client_id = client->id;
969 	if (client_has_capability(client, GOT_CAPA_SIDE_BAND_64K))
970 		ipack.report_progress = 1;
971 
972 	client->delta_cache_fd = got_opentempfd();
973 	if (client->delta_cache_fd == -1)
974 		return got_error_from_errno("got_opentempfd");
975 
976 	if (gotd_imsg_compose_event(&client->repo_child_iev,
977 	    GOTD_IMSG_SEND_PACKFILE, PROC_GOTD, client->delta_cache_fd,
978 	    &ipack, sizeof(ipack)) == -1) {
979 		err = got_error_from_errno("imsg compose SEND_PACKFILE");
980 		close(pipe[0]);
981 		close(pipe[1]);
982 		return err;
983 	}
984 
985 	ipipe.client_id = client->id;
986 
987 	/* Send pack pipe end 0 to repo child process. */
988 	if (gotd_imsg_compose_event(&client->repo_child_iev,
989 	    GOTD_IMSG_PACKFILE_PIPE, PROC_GOTD,
990 	    pipe[0], &ipipe, sizeof(ipipe)) == -1) {
991 		err = got_error_from_errno("imsg compose PACKFILE_PIPE");
992 		close(pipe[1]);
993 		return err;
994 	}
995 
996 	/* Send pack pipe end 1 to gotsh(1) (expects just an fd, no data). */
997 	if (gotd_imsg_compose_event(&client->iev,
998 	    GOTD_IMSG_PACKFILE_PIPE, PROC_GOTD, pipe[1], NULL, 0) == -1)
999 		err = got_error_from_errno("imsg compose PACKFILE_PIPE");
1000 
1001 	return err;
1002 }
1003 
1004 static void
1005 session_dispatch_client(int fd, short events, void *arg)
1006 {
1007 	struct gotd_imsgev *iev = arg;
1008 	struct imsgbuf *ibuf = &iev->ibuf;
1009 	struct gotd_session_client *client = &gotd_session_client;
1010 	const struct got_error *err = NULL;
1011 	struct imsg imsg;
1012 	ssize_t n;
1013 
1014 	if (events & EV_WRITE) {
1015 		while (ibuf->w.queued) {
1016 			n = msgbuf_write(&ibuf->w);
1017 			if (n == -1 && errno == EPIPE) {
1018 				/*
1019 				 * The client has closed its socket.
1020 				 * This can happen when Git clients are
1021 				 * done sending pack file data.
1022 				 */
1023 				msgbuf_clear(&ibuf->w);
1024 				continue;
1025 			} else if (n == -1 && errno != EAGAIN) {
1026 				err = got_error_from_errno("imsg_flush");
1027 				disconnect_on_error(client, err);
1028 				return;
1029 			}
1030 			if (n == 0) {
1031 				/* Connection closed. */
1032 				err = got_error(GOT_ERR_EOF);
1033 				disconnect_on_error(client, err);
1034 				return;
1035 			}
1036 		}
1037 	}
1038 
1039 	if ((events & EV_READ) == 0)
1040 		return;
1041 
1042 	memset(&imsg, 0, sizeof(imsg));
1043 
1044 	while (err == NULL) {
1045 		err = gotd_imsg_recv(&imsg, ibuf, 0);
1046 		if (err) {
1047 			if (err->code == GOT_ERR_PRIVSEP_READ)
1048 				err = NULL;
1049 			break;
1050 		}
1051 
1052 		evtimer_del(&client->tmo);
1053 
1054 		switch (imsg.hdr.type) {
1055 		case GOTD_IMSG_CAPABILITIES:
1056 			if (client->state != GOTD_STATE_EXPECT_CAPABILITIES) {
1057 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1058 				    "unexpected capabilities received");
1059 				break;
1060 			}
1061 			log_debug("receiving capabilities from uid %d",
1062 			    client->euid);
1063 			err = recv_capabilities(client, &imsg);
1064 			break;
1065 		case GOTD_IMSG_CAPABILITY:
1066 			if (client->state != GOTD_STATE_EXPECT_CAPABILITIES) {
1067 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1068 				    "unexpected capability received");
1069 				break;
1070 			}
1071 			err = recv_capability(client, &imsg);
1072 			if (err || client->ncapabilities < client->ncapa_alloc)
1073 				break;
1074 			if (!client->is_writing) {
1075 				client->state = GOTD_STATE_EXPECT_WANT;
1076 				client->accept_flush_pkt = 1;
1077 				log_debug("uid %d: expecting want-lines",
1078 				    client->euid);
1079 			} else if (client->is_writing) {
1080 				client->state = GOTD_STATE_EXPECT_REF_UPDATE;
1081 				client->accept_flush_pkt = 1;
1082 				log_debug("uid %d: expecting ref-update-lines",
1083 				    client->euid);
1084 			} else
1085 				fatalx("client %d is both reading and writing",
1086 				    client->euid);
1087 			break;
1088 		case GOTD_IMSG_WANT:
1089 			if (client->state != GOTD_STATE_EXPECT_WANT) {
1090 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1091 				    "unexpected want-line received");
1092 				break;
1093 			}
1094 			log_debug("received want-line from uid %d",
1095 			    client->euid);
1096 			err = ensure_client_is_reading(client);
1097 			if (err)
1098 				break;
1099 			client->accept_flush_pkt = 1;
1100 			err = forward_want(client, &imsg);
1101 			break;
1102 		case GOTD_IMSG_REF_UPDATE:
1103 			if (client->state != GOTD_STATE_EXPECT_REF_UPDATE &&
1104 			    client->state !=
1105 			    GOTD_STATE_EXPECT_MORE_REF_UPDATES) {
1106 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1107 				    "unexpected ref-update-line received");
1108 				break;
1109 			}
1110 			log_debug("received ref-update-line from uid %d",
1111 			    client->euid);
1112 			err = ensure_client_is_writing(client);
1113 			if (err)
1114 				break;
1115 			err = forward_ref_update(client, &imsg);
1116 			if (err)
1117 				break;
1118 			client->state = GOTD_STATE_EXPECT_MORE_REF_UPDATES;
1119 			client->accept_flush_pkt = 1;
1120 			break;
1121 		case GOTD_IMSG_HAVE:
1122 			if (client->state != GOTD_STATE_EXPECT_HAVE) {
1123 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1124 				    "unexpected have-line received");
1125 				break;
1126 			}
1127 			log_debug("received have-line from uid %d",
1128 			    client->euid);
1129 			err = ensure_client_is_reading(client);
1130 			if (err)
1131 				break;
1132 			err = forward_have(client, &imsg);
1133 			if (err)
1134 				break;
1135 			client->accept_flush_pkt = 1;
1136 			break;
1137 		case GOTD_IMSG_FLUSH:
1138 			if (client->state == GOTD_STATE_EXPECT_WANT ||
1139 			    client->state == GOTD_STATE_EXPECT_HAVE) {
1140 				err = ensure_client_is_reading(client);
1141 				if (err)
1142 					break;
1143 			} else if (client->state ==
1144 			    GOTD_STATE_EXPECT_MORE_REF_UPDATES) {
1145 				err = ensure_client_is_writing(client);
1146 				if (err)
1147 					break;
1148 			} else if (client->state != GOTD_STATE_EXPECT_DONE) {
1149 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1150 				    "unexpected flush-pkt received");
1151 				break;
1152 			}
1153 			if (!client->accept_flush_pkt) {
1154 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1155 				    "unexpected flush-pkt received");
1156 				break;
1157 			}
1158 
1159 			/*
1160 			 * Accept just one flush packet at a time.
1161 			 * Future client state transitions will set this flag
1162 			 * again if another flush packet is expected.
1163 			 */
1164 			client->accept_flush_pkt = 0;
1165 
1166 			log_debug("received flush-pkt from uid %d",
1167 			    client->euid);
1168 			if (client->state == GOTD_STATE_EXPECT_WANT) {
1169 				client->state = GOTD_STATE_EXPECT_HAVE;
1170 				log_debug("uid %d: expecting have-lines",
1171 				    client->euid);
1172 			} else if (client->state == GOTD_STATE_EXPECT_HAVE) {
1173 				client->state = GOTD_STATE_EXPECT_DONE;
1174 				client->accept_flush_pkt = 1;
1175 				log_debug("uid %d: expecting 'done'",
1176 				    client->euid);
1177 			} else if (client->state ==
1178 			    GOTD_STATE_EXPECT_MORE_REF_UPDATES) {
1179 				client->state = GOTD_STATE_EXPECT_PACKFILE;
1180 				log_debug("uid %d: expecting packfile",
1181 				    client->euid);
1182 				err = recv_packfile(client);
1183 			} else if (client->state != GOTD_STATE_EXPECT_DONE) {
1184 				/* should not happen, see above */
1185 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1186 				    "unexpected client state");
1187 				break;
1188 			}
1189 			break;
1190 		case GOTD_IMSG_DONE:
1191 			if (client->state != GOTD_STATE_EXPECT_HAVE &&
1192 			    client->state != GOTD_STATE_EXPECT_DONE) {
1193 				err = got_error_msg(GOT_ERR_BAD_REQUEST,
1194 				    "unexpected flush-pkt received");
1195 				break;
1196 			}
1197 			log_debug("received 'done' from uid %d", client->euid);
1198 			err = ensure_client_is_reading(client);
1199 			if (err)
1200 				break;
1201 			client->state = GOTD_STATE_DONE;
1202 			client->accept_flush_pkt = 1;
1203 			err = send_packfile(client);
1204 			break;
1205 		default:
1206 			log_debug("unexpected imsg %d", imsg.hdr.type);
1207 			err = got_error(GOT_ERR_PRIVSEP_MSG);
1208 			break;
1209 		}
1210 
1211 		imsg_free(&imsg);
1212 	}
1213 
1214 	if (err) {
1215 		if (err->code != GOT_ERR_EOF ||
1216 		    client->state != GOTD_STATE_EXPECT_PACKFILE)
1217 			disconnect_on_error(client, err);
1218 	} else {
1219 		gotd_imsg_event_add(iev);
1220 		evtimer_add(&client->tmo, &gotd_session.request_timeout);
1221 	}
1222 }
1223 
1224 static const struct got_error *
1225 list_refs_request(void)
1226 {
1227 	static const struct got_error *err;
1228 	struct gotd_session_client *client = &gotd_session_client;
1229 	struct gotd_imsgev *iev = &client->repo_child_iev;
1230 	struct gotd_imsg_list_refs_internal ilref;
1231 	int fd;
1232 
1233 	if (client->state != GOTD_STATE_EXPECT_LIST_REFS)
1234 		return got_error(GOT_ERR_PRIVSEP_MSG);
1235 
1236 	memset(&ilref, 0, sizeof(ilref));
1237 	ilref.client_id = client->id;
1238 
1239 	fd = dup(client->fd);
1240 	if (fd == -1)
1241 		return got_error_from_errno("dup");
1242 
1243 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_LIST_REFS_INTERNAL,
1244 	    PROC_SESSION, fd, &ilref, sizeof(ilref)) == -1) {
1245 		err = got_error_from_errno("imsg compose LIST_REFS_INTERNAL");
1246 		close(fd);
1247 		return err;
1248 	}
1249 
1250 	client->state = GOTD_STATE_EXPECT_CAPABILITIES;
1251 	log_debug("uid %d: expecting capabilities", client->euid);
1252 	return NULL;
1253 }
1254 
1255 static const struct got_error *
1256 recv_connect(struct imsg *imsg)
1257 {
1258 	struct gotd_session_client *client = &gotd_session_client;
1259 	struct gotd_imsg_connect iconnect;
1260 	size_t datalen;
1261 
1262 	if (client->state != GOTD_STATE_EXPECT_LIST_REFS)
1263 		return got_error(GOT_ERR_PRIVSEP_MSG);
1264 
1265 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1266 	if (datalen != sizeof(iconnect))
1267 		return got_error(GOT_ERR_PRIVSEP_LEN);
1268 	memcpy(&iconnect, imsg->data, sizeof(iconnect));
1269 
1270 	if (imsg->fd == -1)
1271 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
1272 
1273 	client->fd = imsg->fd;
1274 	client->euid = iconnect.euid;
1275 	client->egid = iconnect.egid;
1276 
1277 	imsg_init(&client->iev.ibuf, client->fd);
1278 	client->iev.handler = session_dispatch_client;
1279 	client->iev.events = EV_READ;
1280 	client->iev.handler_arg = NULL;
1281 	event_set(&client->iev.ev, client->iev.ibuf.fd, EV_READ,
1282 	    session_dispatch_client, &client->iev);
1283 	gotd_imsg_event_add(&client->iev);
1284 	evtimer_set(&client->tmo, gotd_request_timeout, client);
1285 
1286 	return NULL;
1287 }
1288 
1289 static const struct got_error *
1290 recv_repo_child(struct imsg *imsg)
1291 {
1292 	struct gotd_imsg_connect_repo_child ichild;
1293 	struct gotd_session_client *client = &gotd_session_client;
1294 	size_t datalen;
1295 
1296 	if (client->state != GOTD_STATE_EXPECT_LIST_REFS)
1297 		return got_error(GOT_ERR_PRIVSEP_MSG);
1298 
1299 	/* We should already have received a pipe to the listener. */
1300 	if (client->fd == -1)
1301 		return got_error(GOT_ERR_PRIVSEP_MSG);
1302 
1303 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
1304 	if (datalen != sizeof(ichild))
1305 		return got_error(GOT_ERR_PRIVSEP_LEN);
1306 
1307 	memcpy(&ichild, imsg->data, sizeof(ichild));
1308 
1309 	client->id = ichild.client_id;
1310 	if (ichild.proc_id == PROC_REPO_WRITE)
1311 		client->is_writing = 1;
1312 	else if (ichild.proc_id == PROC_REPO_READ)
1313 		client->is_writing = 0;
1314 	else
1315 		return got_error_msg(GOT_ERR_PRIVSEP_MSG,
1316 		    "bad child process type");
1317 
1318 	if (imsg->fd == -1)
1319 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
1320 
1321 	imsg_init(&client->repo_child_iev.ibuf, imsg->fd);
1322 	client->repo_child_iev.handler = session_dispatch_repo_child;
1323 	client->repo_child_iev.events = EV_READ;
1324 	client->repo_child_iev.handler_arg = NULL;
1325 	event_set(&client->repo_child_iev.ev, client->repo_child_iev.ibuf.fd,
1326 	    EV_READ, session_dispatch_repo_child, &client->repo_child_iev);
1327 	gotd_imsg_event_add(&client->repo_child_iev);
1328 
1329 	/* The "recvfd" pledge promise is no longer needed. */
1330 	if (pledge("stdio rpath wpath cpath sendfd fattr flock", NULL) == -1)
1331 		fatal("pledge");
1332 
1333 	return NULL;
1334 }
1335 
1336 static void
1337 session_dispatch(int fd, short event, void *arg)
1338 {
1339 	struct gotd_imsgev *iev = arg;
1340 	struct imsgbuf *ibuf = &iev->ibuf;
1341 	struct gotd_session_client *client = &gotd_session_client;
1342 	ssize_t n;
1343 	int shut = 0;
1344 	struct imsg imsg;
1345 
1346 	if (event & EV_READ) {
1347 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1348 			fatal("imsg_read error");
1349 		if (n == 0) {
1350 			/* Connection closed. */
1351 			shut = 1;
1352 			goto done;
1353 		}
1354 	}
1355 
1356 	if (event & EV_WRITE) {
1357 		n = msgbuf_write(&ibuf->w);
1358 		if (n == -1 && errno != EAGAIN)
1359 			fatal("msgbuf_write");
1360 		if (n == 0) {
1361 			/* Connection closed. */
1362 			shut = 1;
1363 			goto done;
1364 		}
1365 	}
1366 
1367 	for (;;) {
1368 		const struct got_error *err = NULL;
1369 		uint32_t client_id = 0;
1370 		int do_disconnect = 0, do_list_refs = 0;
1371 
1372 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1373 			fatal("%s: imsg_get error", __func__);
1374 		if (n == 0)	/* No more messages. */
1375 			break;
1376 
1377 		switch (imsg.hdr.type) {
1378 		case GOTD_IMSG_ERROR:
1379 			do_disconnect = 1;
1380 			err = gotd_imsg_recv_error(&client_id, &imsg);
1381 			break;
1382 		case GOTD_IMSG_CONNECT:
1383 			err = recv_connect(&imsg);
1384 			break;
1385 		case GOTD_IMSG_DISCONNECT:
1386 			do_disconnect = 1;
1387 			break;
1388 		case GOTD_IMSG_CONNECT_REPO_CHILD:
1389 			err = recv_repo_child(&imsg);
1390 			if (err)
1391 				break;
1392 			do_list_refs = 1;
1393 			break;
1394 		default:
1395 			log_debug("unexpected imsg %d", imsg.hdr.type);
1396 			break;
1397 		}
1398 		imsg_free(&imsg);
1399 
1400 		if (do_disconnect) {
1401 			if (err)
1402 				disconnect_on_error(client, err);
1403 			else
1404 				disconnect(client);
1405 		} else if (do_list_refs)
1406 			err = list_refs_request();
1407 
1408 		if (err)
1409 			log_warnx("uid %d: %s", client->euid, err->msg);
1410 	}
1411 done:
1412 	if (!shut) {
1413 		gotd_imsg_event_add(iev);
1414 	} else {
1415 		/* This pipe is dead. Remove its event handler */
1416 		event_del(&iev->ev);
1417 		event_loopexit(NULL);
1418 	}
1419 }
1420 
1421 void
1422 session_main(const char *title, const char *repo_path,
1423     int *pack_fds, int *temp_fds, struct timeval *request_timeout)
1424 {
1425 	const struct got_error *err = NULL;
1426 	struct event evsigint, evsigterm, evsighup, evsigusr1;
1427 
1428 	gotd_session.title = title;
1429 	gotd_session.pid = getpid();
1430 	gotd_session.pack_fds = pack_fds;
1431 	gotd_session.temp_fds = temp_fds;
1432 	memcpy(&gotd_session.request_timeout, request_timeout,
1433 	    sizeof(gotd_session.request_timeout));
1434 
1435 	err = got_repo_open(&gotd_session.repo, repo_path, NULL, pack_fds);
1436 	if (err)
1437 		goto done;
1438 	if (!got_repo_is_bare(gotd_session.repo)) {
1439 		err = got_error_msg(GOT_ERR_NOT_GIT_REPO,
1440 		    "bare git repository required");
1441 		goto done;
1442 	}
1443 
1444 	got_repo_temp_fds_set(gotd_session.repo, temp_fds);
1445 
1446 	signal_set(&evsigint, SIGINT, gotd_session_sighdlr, NULL);
1447 	signal_set(&evsigterm, SIGTERM, gotd_session_sighdlr, NULL);
1448 	signal_set(&evsighup, SIGHUP, gotd_session_sighdlr, NULL);
1449 	signal_set(&evsigusr1, SIGUSR1, gotd_session_sighdlr, NULL);
1450 	signal(SIGPIPE, SIG_IGN);
1451 
1452 	signal_add(&evsigint, NULL);
1453 	signal_add(&evsigterm, NULL);
1454 	signal_add(&evsighup, NULL);
1455 	signal_add(&evsigusr1, NULL);
1456 
1457 	gotd_session_client.state = GOTD_STATE_EXPECT_LIST_REFS;
1458 	gotd_session_client.fd = -1;
1459 	gotd_session_client.nref_updates = -1;
1460 	gotd_session_client.delta_cache_fd = -1;
1461 	gotd_session_client.accept_flush_pkt = 1;
1462 
1463 	imsg_init(&gotd_session.parent_iev.ibuf, GOTD_FILENO_MSG_PIPE);
1464 	gotd_session.parent_iev.handler = session_dispatch;
1465 	gotd_session.parent_iev.events = EV_READ;
1466 	gotd_session.parent_iev.handler_arg = NULL;
1467 	event_set(&gotd_session.parent_iev.ev, gotd_session.parent_iev.ibuf.fd,
1468 	    EV_READ, session_dispatch, &gotd_session.parent_iev);
1469 	if (gotd_imsg_compose_event(&gotd_session.parent_iev,
1470 	    GOTD_IMSG_CLIENT_SESSION_READY, PROC_SESSION, -1, NULL, 0) == -1) {
1471 		err = got_error_from_errno("imsg compose CLIENT_SESSION_READY");
1472 		goto done;
1473 	}
1474 
1475 	event_dispatch();
1476 done:
1477 	if (err)
1478 		log_warnx("%s: %s", title, err->msg);
1479 	gotd_session_shutdown();
1480 }
1481 
1482 void
1483 gotd_session_shutdown(void)
1484 {
1485 	log_debug("shutting down");
1486 	if (gotd_session.repo)
1487 		got_repo_close(gotd_session.repo);
1488 	got_repo_pack_fds_close(gotd_session.pack_fds);
1489 	got_repo_temp_fds_close(gotd_session.temp_fds);
1490 	exit(0);
1491 }