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Date:: Sat Feb 4 13:58:38 2023 UTC
Message:: rename sha1.c to hash.c
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1 /*
2  * Copyright (c) 2022 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/queue.h>
18 #include <sys/tree.h>
19 #include <sys/time.h>
20 #include <sys/types.h>
21 #include <sys/stat.h>
22 #include <sys/socket.h>
23 #include <sys/un.h>
24 #include <sys/wait.h>
25 
26 #include <fcntl.h>
27 #include <err.h>
28 #include <errno.h>
29 #include <event.h>
30 #include <limits.h>
31 #include <pwd.h>
32 #include <imsg.h>
33 #include <sha1.h>
34 #include <sha2.h>
35 #include <signal.h>
36 #include <siphash.h>
37 #include <stdarg.h>
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <syslog.h>
42 #include <unistd.h>
43 
44 #include "got_error.h"
45 #include "got_opentemp.h"
46 #include "got_path.h"
47 #include "got_repository.h"
48 #include "got_object.h"
49 #include "got_reference.h"
50 
51 #include "got_lib_delta.h"
52 #include "got_lib_object.h"
53 #include "got_lib_object_cache.h"
54 #include "got_lib_hash.h"
55 #include "got_lib_gitproto.h"
56 #include "got_lib_pack.h"
57 #include "got_lib_repository.h"
58 
59 #include "gotd.h"
60 #include "log.h"
61 #include "listen.h"
62 #include "auth.h"
63 #include "session.h"
64 #include "repo_read.h"
65 #include "repo_write.h"
66 
67 #ifndef nitems
68 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
69 #endif
70 
71 enum gotd_client_state {
72 	GOTD_CLIENT_STATE_NEW,
73 	GOTD_CLIENT_STATE_ACCESS_GRANTED,
74 };
75 
76 struct gotd_client {
77 	STAILQ_ENTRY(gotd_client)	 entry;
78 	enum gotd_client_state		 state;
79 	uint32_t			 id;
80 	int				 fd;
81 	struct gotd_imsgev		 iev;
82 	struct event			 tmo;
83 	uid_t				 euid;
84 	gid_t				 egid;
85 	struct gotd_child_proc		*repo;
86 	struct gotd_child_proc		*auth;
87 	struct gotd_child_proc		*session;
88 	int				 required_auth;
89 };
90 STAILQ_HEAD(gotd_clients, gotd_client);
91 
92 static struct gotd_clients gotd_clients[GOTD_CLIENT_TABLE_SIZE];
93 static SIPHASH_KEY clients_hash_key;
94 volatile int client_cnt;
95 static struct timeval auth_timeout = { 5, 0 };
96 static struct gotd gotd;
97 
98 void gotd_sighdlr(int sig, short event, void *arg);
99 static void gotd_shutdown(void);
100 static const struct got_error *start_session_child(struct gotd_client *,
101     struct gotd_repo *, char *, const char *, int, int);
102 static const struct got_error *start_repo_child(struct gotd_client *,
103     enum gotd_procid, struct gotd_repo *, char *, const char *, int, int);
104 static const struct got_error *start_auth_child(struct gotd_client *, int,
105     struct gotd_repo *, char *, const char *, int, int);
106 static void kill_proc(struct gotd_child_proc *, int);
107 
108 __dead static void
109 usage()
110 {
111 	fprintf(stderr, "usage: %s [-dnv] [-f config-file]\n", getprogname());
112 	exit(1);
113 }
114 
115 static int
116 unix_socket_listen(const char *unix_socket_path, uid_t uid, gid_t gid)
117 {
118 	struct sockaddr_un sun;
119 	int fd = -1;
120 	mode_t old_umask, mode;
121 
122 	fd = socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK| SOCK_CLOEXEC, 0);
123 	if (fd == -1) {
124 		log_warn("socket");
125 		return -1;
126 	}
127 
128 	sun.sun_family = AF_UNIX;
129 	if (strlcpy(sun.sun_path, unix_socket_path,
130 	    sizeof(sun.sun_path)) >= sizeof(sun.sun_path)) {
131 		log_warnx("%s: name too long", unix_socket_path);
132 		close(fd);
133 		return -1;
134 	}
135 
136 	if (unlink(unix_socket_path) == -1) {
137 		if (errno != ENOENT) {
138 			log_warn("unlink %s", unix_socket_path);
139 			close(fd);
140 			return -1;
141 		}
142 	}
143 
144 	old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH);
145 	mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH;
146 
147 	if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) {
148 		log_warn("bind: %s", unix_socket_path);
149 		close(fd);
150 		umask(old_umask);
151 		return -1;
152 	}
153 
154 	umask(old_umask);
155 
156 	if (chmod(unix_socket_path, mode) == -1) {
157 		log_warn("chmod %o %s", mode, unix_socket_path);
158 		close(fd);
159 		unlink(unix_socket_path);
160 		return -1;
161 	}
162 
163 	if (chown(unix_socket_path, uid, gid) == -1) {
164 		log_warn("chown %s uid=%d gid=%d", unix_socket_path, uid, gid);
165 		close(fd);
166 		unlink(unix_socket_path);
167 		return -1;
168 	}
169 
170 	if (listen(fd, GOTD_UNIX_SOCKET_BACKLOG) == -1) {
171 		log_warn("listen");
172 		close(fd);
173 		unlink(unix_socket_path);
174 		return -1;
175 	}
176 
177 	return fd;
178 }
179 
180 static uint64_t
181 client_hash(uint32_t client_id)
182 {
183 	return SipHash24(&clients_hash_key, &client_id, sizeof(client_id));
184 }
185 
186 static void
187 add_client(struct gotd_client *client)
188 {
189 	uint64_t slot = client_hash(client->id) % nitems(gotd_clients);
190 	STAILQ_INSERT_HEAD(&gotd_clients[slot], client, entry);
191 	client_cnt++;
192 }
193 
194 static struct gotd_client *
195 find_client(uint32_t client_id)
196 {
197 	uint64_t slot;
198 	struct gotd_client *c;
199 
200 	slot = client_hash(client_id) % nitems(gotd_clients);
201 	STAILQ_FOREACH(c, &gotd_clients[slot], entry) {
202 		if (c->id == client_id)
203 			return c;
204 	}
205 
206 	return NULL;
207 }
208 
209 static struct gotd_client *
210 find_client_by_proc_fd(int fd)
211 {
212 	uint64_t slot;
213 
214 	for (slot = 0; slot < nitems(gotd_clients); slot++) {
215 		struct gotd_client *c;
216 
217 		STAILQ_FOREACH(c, &gotd_clients[slot], entry) {
218 			if (c->repo && c->repo->iev.ibuf.fd == fd)
219 				return c;
220 			if (c->auth && c->auth->iev.ibuf.fd == fd)
221 				return c;
222 			if (c->session && c->session->iev.ibuf.fd == fd)
223 				return c;
224 		}
225 	}
226 
227 	return NULL;
228 }
229 
230 static int
231 client_is_reading(struct gotd_client *client)
232 {
233 	return (client->required_auth &
234 	    (GOTD_AUTH_READ | GOTD_AUTH_WRITE)) == GOTD_AUTH_READ;
235 }
236 
237 static int
238 client_is_writing(struct gotd_client *client)
239 {
240 	return (client->required_auth &
241 	    (GOTD_AUTH_READ | GOTD_AUTH_WRITE)) ==
242 	    (GOTD_AUTH_READ | GOTD_AUTH_WRITE);
243 }
244 
245 static const struct got_error *
246 ensure_client_is_not_writing(struct gotd_client *client)
247 {
248 	if (client_is_writing(client)) {
249 		return got_error_fmt(GOT_ERR_BAD_PACKET,
250 		    "uid %d made a read-request but is writing to "
251 		    "a repository", client->euid);
252 	}
253 
254 	return NULL;
255 }
256 
257 static const struct got_error *
258 ensure_client_is_not_reading(struct gotd_client *client)
259 {
260 	if (client_is_reading(client)) {
261 		return got_error_fmt(GOT_ERR_BAD_PACKET,
262 		    "uid %d made a write-request but is reading from "
263 		    "a repository", client->euid);
264 	}
265 
266 	return NULL;
267 }
268 
269 static void
270 wait_for_child(pid_t child_pid)
271 {
272 	pid_t pid;
273 	int status;
274 
275 	log_debug("waiting for child PID %ld to terminate",
276 	    (long)child_pid);
277 
278 	do {
279 		pid = waitpid(child_pid, &status, WNOHANG);
280 		if (pid == -1) {
281 			if (errno != EINTR && errno != ECHILD)
282 				fatal("wait");
283 		} else if (WIFSIGNALED(status)) {
284 			log_warnx("child PID %ld terminated; signal %d",
285 			    (long)pid, WTERMSIG(status));
286 		}
287 	} while (pid != -1 || (pid == -1 && errno == EINTR));
288 }
289 
290 static void
291 proc_done(struct gotd_child_proc *proc)
292 {
293 	event_del(&proc->iev.ev);
294 	msgbuf_clear(&proc->iev.ibuf.w);
295 	close(proc->iev.ibuf.fd);
296 	kill_proc(proc, 0);
297 	wait_for_child(proc->pid);
298 	free(proc);
299 }
300 
301 static void
302 kill_auth_proc(struct gotd_client *client)
303 {
304 	struct gotd_child_proc *proc;
305 
306 	if (client->auth == NULL)
307 		return;
308 
309 	proc = client->auth;
310 	client->auth = NULL;
311 
312 	proc_done(proc);
313 }
314 
315 static void
316 kill_session_proc(struct gotd_client *client)
317 {
318 	struct gotd_child_proc *proc;
319 
320 	if (client->session == NULL)
321 		return;
322 
323 	proc = client->session;
324 	client->session = NULL;
325 
326 	proc_done(proc);
327 }
328 
329 static void
330 disconnect(struct gotd_client *client)
331 {
332 	struct gotd_imsg_disconnect idisconnect;
333 	struct gotd_child_proc *proc = client->repo;
334 	struct gotd_child_proc *listen_proc = &gotd.listen_proc;
335 	uint64_t slot;
336 
337 	log_debug("uid %d: disconnecting", client->euid);
338 
339 	kill_auth_proc(client);
340 	kill_session_proc(client);
341 
342 	idisconnect.client_id = client->id;
343 	if (proc) {
344 		if (gotd_imsg_compose_event(&proc->iev,
345 		    GOTD_IMSG_DISCONNECT, PROC_GOTD, -1,
346 		    &idisconnect, sizeof(idisconnect)) == -1)
347 			log_warn("imsg compose DISCONNECT");
348 
349 		msgbuf_clear(&proc->iev.ibuf.w);
350 		close(proc->iev.ibuf.fd);
351 		kill_proc(proc, 0);
352 		wait_for_child(proc->pid);
353 		free(proc);
354 		proc = NULL;
355 	}
356 
357 	if (gotd_imsg_compose_event(&listen_proc->iev,
358 	    GOTD_IMSG_DISCONNECT, PROC_GOTD, -1,
359 	    &idisconnect, sizeof(idisconnect)) == -1)
360 		log_warn("imsg compose DISCONNECT");
361 
362 	slot = client_hash(client->id) % nitems(gotd_clients);
363 	STAILQ_REMOVE(&gotd_clients[slot], client, gotd_client, entry);
364 	imsg_clear(&client->iev.ibuf);
365 	event_del(&client->iev.ev);
366 	evtimer_del(&client->tmo);
367 	if (client->fd != -1)
368 		close(client->fd);
369 	else if (client->iev.ibuf.fd != -1)
370 		close(client->iev.ibuf.fd);
371 	free(client);
372 	client_cnt--;
373 }
374 
375 static void
376 disconnect_on_error(struct gotd_client *client, const struct got_error *err)
377 {
378 	struct imsgbuf ibuf;
379 
380 	log_warnx("uid %d: %s", client->euid, err->msg);
381 	if (err->code != GOT_ERR_EOF && client->fd != -1) {
382 		imsg_init(&ibuf, client->fd);
383 		gotd_imsg_send_error(&ibuf, 0, PROC_GOTD, err);
384 		imsg_clear(&ibuf);
385 	}
386 	disconnect(client);
387 }
388 
389 static const struct got_error *
390 send_repo_info(struct gotd_imsgev *iev, struct gotd_repo *repo)
391 {
392 	const struct got_error *err = NULL;
393 	struct gotd_imsg_info_repo irepo;
394 
395 	memset(&irepo, 0, sizeof(irepo));
396 
397 	if (strlcpy(irepo.repo_name, repo->name, sizeof(irepo.repo_name))
398 	    >= sizeof(irepo.repo_name))
399 		return got_error_msg(GOT_ERR_NO_SPACE, "repo name too long");
400 	if (strlcpy(irepo.repo_path, repo->path, sizeof(irepo.repo_path))
401 	    >= sizeof(irepo.repo_path))
402 		return got_error_msg(GOT_ERR_NO_SPACE, "repo path too long");
403 
404 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_INFO_REPO, PROC_GOTD, -1,
405 	    &irepo, sizeof(irepo)) == -1) {
406 		err = got_error_from_errno("imsg compose INFO_REPO");
407 		if (err)
408 			return err;
409 	}
410 
411 	return NULL;
412 }
413 
414 static const struct got_error *
415 send_client_info(struct gotd_imsgev *iev, struct gotd_client *client)
416 {
417 	const struct got_error *err = NULL;
418 	struct gotd_imsg_info_client iclient;
419 	struct gotd_child_proc *proc;
420 
421 	memset(&iclient, 0, sizeof(iclient));
422 	iclient.euid = client->euid;
423 	iclient.egid = client->egid;
424 
425 	proc = client->repo;
426 	if (proc) {
427 		if (strlcpy(iclient.repo_name, proc->repo_path,
428 		    sizeof(iclient.repo_name)) >= sizeof(iclient.repo_name)) {
429 			return got_error_msg(GOT_ERR_NO_SPACE,
430 			    "repo name too long");
431 		}
432 		if (client_is_writing(client))
433 			iclient.is_writing = 1;
434 
435 		iclient.repo_child_pid = proc->pid;
436 	}
437 
438 	if (client->session)
439 		iclient.session_child_pid = client->session->pid;
440 
441 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_INFO_CLIENT, PROC_GOTD, -1,
442 	    &iclient, sizeof(iclient)) == -1) {
443 		err = got_error_from_errno("imsg compose INFO_CLIENT");
444 		if (err)
445 			return err;
446 	}
447 
448 	return NULL;
449 }
450 
451 static const struct got_error *
452 send_info(struct gotd_client *client)
453 {
454 	const struct got_error *err = NULL;
455 	struct gotd_imsg_info info;
456 	uint64_t slot;
457 	struct gotd_repo *repo;
458 
459 	if (client->euid != 0)
460 		return got_error_set_errno(EPERM, "info");
461 
462 	info.pid = gotd.pid;
463 	info.verbosity = gotd.verbosity;
464 	info.nrepos = gotd.nrepos;
465 	info.nclients = client_cnt - 1;
466 
467 	if (gotd_imsg_compose_event(&client->iev, GOTD_IMSG_INFO, PROC_GOTD, -1,
468 	    &info, sizeof(info)) == -1) {
469 		err = got_error_from_errno("imsg compose INFO");
470 		if (err)
471 			return err;
472 	}
473 
474 	TAILQ_FOREACH(repo, &gotd.repos, entry) {
475 		err = send_repo_info(&client->iev, repo);
476 		if (err)
477 			return err;
478 	}
479 
480 	for (slot = 0; slot < nitems(gotd_clients); slot++) {
481 		struct gotd_client *c;
482 		STAILQ_FOREACH(c, &gotd_clients[slot], entry) {
483 			if (c->id == client->id)
484 				continue;
485 			err = send_client_info(&client->iev, c);
486 			if (err)
487 				return err;
488 		}
489 	}
490 
491 	return NULL;
492 }
493 
494 static const struct got_error *
495 stop_gotd(struct gotd_client *client)
496 {
497 
498 	if (client->euid != 0)
499 		return got_error_set_errno(EPERM, "stop");
500 
501 	gotd_shutdown();
502 	/* NOTREACHED */
503 	return NULL;
504 }
505 
506 static struct gotd_repo *
507 find_repo_by_name(const char *repo_name)
508 {
509 	struct gotd_repo *repo;
510 	size_t namelen;
511 
512 	TAILQ_FOREACH(repo, &gotd.repos, entry) {
513 		namelen = strlen(repo->name);
514 		if (strncmp(repo->name, repo_name, namelen) != 0)
515 			continue;
516 		if (repo_name[namelen] == '\0' ||
517 		    strcmp(&repo_name[namelen], ".git") == 0)
518 			return repo;
519 	}
520 
521 	return NULL;
522 }
523 
524 static const struct got_error *
525 start_client_authentication(struct gotd_client *client, struct imsg *imsg)
526 {
527 	const struct got_error *err;
528 	struct gotd_imsg_list_refs ireq;
529 	struct gotd_repo *repo = NULL;
530 	size_t datalen;
531 
532 	log_debug("list-refs request from uid %d", client->euid);
533 
534 	if (client->state != GOTD_CLIENT_STATE_NEW)
535 		return got_error_msg(GOT_ERR_BAD_REQUEST,
536 		    "unexpected list-refs request received");
537 
538 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
539 	if (datalen != sizeof(ireq))
540 		return got_error(GOT_ERR_PRIVSEP_LEN);
541 
542 	memcpy(&ireq, imsg->data, datalen);
543 
544 	if (ireq.client_is_reading) {
545 		err = ensure_client_is_not_writing(client);
546 		if (err)
547 			return err;
548 		repo = find_repo_by_name(ireq.repo_name);
549 		if (repo == NULL)
550 			return got_error(GOT_ERR_NOT_GIT_REPO);
551 		err = start_auth_child(client, GOTD_AUTH_READ, repo,
552 		    gotd.argv0, gotd.confpath, gotd.daemonize,
553 		    gotd.verbosity);
554 		if (err)
555 			return err;
556 	} else {
557 		err = ensure_client_is_not_reading(client);
558 		if (err)
559 			return err;
560 		repo = find_repo_by_name(ireq.repo_name);
561 		if (repo == NULL)
562 			return got_error(GOT_ERR_NOT_GIT_REPO);
563 		err = start_auth_child(client,
564 		    GOTD_AUTH_READ | GOTD_AUTH_WRITE,
565 		    repo, gotd.argv0, gotd.confpath, gotd.daemonize,
566 		    gotd.verbosity);
567 		if (err)
568 			return err;
569 	}
570 
571 	evtimer_add(&client->tmo, &auth_timeout);
572 
573 	/* Flow continues upon authentication successs/failure or timeout. */
574 	return NULL;
575 }
576 
577 static void
578 gotd_request(int fd, short events, void *arg)
579 {
580 	struct gotd_imsgev *iev = arg;
581 	struct imsgbuf *ibuf = &iev->ibuf;
582 	struct gotd_client *client = iev->handler_arg;
583 	const struct got_error *err = NULL;
584 	struct imsg imsg;
585 	ssize_t n;
586 
587 	if (events & EV_WRITE) {
588 		while (ibuf->w.queued) {
589 			n = msgbuf_write(&ibuf->w);
590 			if (n == -1 && errno == EPIPE) {
591 				/*
592 				 * The client has closed its socket.
593 				 * This can happen when Git clients are
594 				 * done sending pack file data.
595 				 */
596 				msgbuf_clear(&ibuf->w);
597 				continue;
598 			} else if (n == -1 && errno != EAGAIN) {
599 				err = got_error_from_errno("imsg_flush");
600 				disconnect_on_error(client, err);
601 				return;
602 			}
603 			if (n == 0) {
604 				/* Connection closed. */
605 				err = got_error(GOT_ERR_EOF);
606 				disconnect_on_error(client, err);
607 				return;
608 			}
609 		}
610 
611 		/* Disconnect gotctl(8) now that messages have been sent. */
612 		if (!client_is_reading(client) && !client_is_writing(client)) {
613 			disconnect(client);
614 			return;
615 		}
616 	}
617 
618 	if ((events & EV_READ) == 0)
619 		return;
620 
621 	memset(&imsg, 0, sizeof(imsg));
622 
623 	while (err == NULL) {
624 		err = gotd_imsg_recv(&imsg, ibuf, 0);
625 		if (err) {
626 			if (err->code == GOT_ERR_PRIVSEP_READ)
627 				err = NULL;
628 			break;
629 		}
630 
631 		evtimer_del(&client->tmo);
632 
633 		switch (imsg.hdr.type) {
634 		case GOTD_IMSG_INFO:
635 			err = send_info(client);
636 			break;
637 		case GOTD_IMSG_STOP:
638 			err = stop_gotd(client);
639 			break;
640 		case GOTD_IMSG_LIST_REFS:
641 			err = start_client_authentication(client, &imsg);
642 			break;
643 		default:
644 			log_debug("unexpected imsg %d", imsg.hdr.type);
645 			err = got_error(GOT_ERR_PRIVSEP_MSG);
646 			break;
647 		}
648 
649 		imsg_free(&imsg);
650 	}
651 
652 	if (err) {
653 		disconnect_on_error(client, err);
654 	} else {
655 		gotd_imsg_event_add(&client->iev);
656 	}
657 }
658 
659 static void
660 gotd_auth_timeout(int fd, short events, void *arg)
661 {
662 	struct gotd_client *client = arg;
663 
664 	log_debug("disconnecting uid %d due to authentication timeout",
665 	    client->euid);
666 	disconnect(client);
667 }
668 
669 static const struct got_error *
670 recv_connect(uint32_t *client_id, struct imsg *imsg)
671 {
672 	const struct got_error *err = NULL;
673 	struct gotd_imsg_connect iconnect;
674 	size_t datalen;
675 	int s = -1;
676 	struct gotd_client *client = NULL;
677 
678 	*client_id = 0;
679 
680 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
681 	if (datalen != sizeof(iconnect))
682 		return got_error(GOT_ERR_PRIVSEP_LEN);
683 	memcpy(&iconnect, imsg->data, sizeof(iconnect));
684 
685 	s = imsg->fd;
686 	if (s == -1) {
687 		err = got_error(GOT_ERR_PRIVSEP_NO_FD);
688 		goto done;
689 	}
690 
691 	if (find_client(iconnect.client_id)) {
692 		err = got_error_msg(GOT_ERR_CLIENT_ID, "duplicate client ID");
693 		goto done;
694 	}
695 
696 	client = calloc(1, sizeof(*client));
697 	if (client == NULL) {
698 		err = got_error_from_errno("calloc");
699 		goto done;
700 	}
701 
702 	*client_id = iconnect.client_id;
703 
704 	client->state = GOTD_CLIENT_STATE_NEW;
705 	client->id = iconnect.client_id;
706 	client->fd = s;
707 	s = -1;
708 	/* The auth process will verify UID/GID for us. */
709 	client->euid = iconnect.euid;
710 	client->egid = iconnect.egid;
711 
712 	imsg_init(&client->iev.ibuf, client->fd);
713 	client->iev.handler = gotd_request;
714 	client->iev.events = EV_READ;
715 	client->iev.handler_arg = client;
716 
717 	event_set(&client->iev.ev, client->fd, EV_READ, gotd_request,
718 	    &client->iev);
719 	gotd_imsg_event_add(&client->iev);
720 
721 	evtimer_set(&client->tmo, gotd_auth_timeout, client);
722 
723 	add_client(client);
724 	log_debug("%s: new client uid %d connected on fd %d", __func__,
725 	    client->euid, client->fd);
726 done:
727 	if (err) {
728 		struct gotd_child_proc *listen_proc = &gotd.listen_proc;
729 		struct gotd_imsg_disconnect idisconnect;
730 
731 		idisconnect.client_id = client->id;
732 		if (gotd_imsg_compose_event(&listen_proc->iev,
733 		    GOTD_IMSG_DISCONNECT, PROC_GOTD, -1,
734 		    &idisconnect, sizeof(idisconnect)) == -1)
735 			log_warn("imsg compose DISCONNECT");
736 
737 		if (s != -1)
738 			close(s);
739 	}
740 
741 	return err;
742 }
743 
744 static const char *gotd_proc_names[PROC_MAX] = {
745 	"parent",
746 	"listen",
747 	"auth",
748 	"session",
749 	"repo_read",
750 	"repo_write"
751 };
752 
753 static void
754 kill_proc(struct gotd_child_proc *proc, int fatal)
755 {
756 	if (fatal) {
757 		log_warnx("sending SIGKILL to PID %d", proc->pid);
758 		kill(proc->pid, SIGKILL);
759 	} else
760 		kill(proc->pid, SIGTERM);
761 }
762 
763 static void
764 gotd_shutdown(void)
765 {
766 	struct gotd_child_proc *proc;
767 	uint64_t slot;
768 
769 	log_debug("shutting down");
770 	for (slot = 0; slot < nitems(gotd_clients); slot++) {
771 		struct gotd_client *c, *tmp;
772 
773 		STAILQ_FOREACH_SAFE(c, &gotd_clients[slot], entry, tmp)
774 			disconnect(c);
775 	}
776 
777 	proc = &gotd.listen_proc;
778 	msgbuf_clear(&proc->iev.ibuf.w);
779 	close(proc->iev.ibuf.fd);
780 	kill_proc(proc, 0);
781 	wait_for_child(proc->pid);
782 
783 	log_info("terminating");
784 	exit(0);
785 }
786 
787 void
788 gotd_sighdlr(int sig, short event, void *arg)
789 {
790 	/*
791 	 * Normal signal handler rules don't apply because libevent
792 	 * decouples for us.
793 	 */
794 
795 	switch (sig) {
796 	case SIGHUP:
797 		log_info("%s: ignoring SIGHUP", __func__);
798 		break;
799 	case SIGUSR1:
800 		log_info("%s: ignoring SIGUSR1", __func__);
801 		break;
802 	case SIGTERM:
803 	case SIGINT:
804 		gotd_shutdown();
805 		break;
806 	default:
807 		fatalx("unexpected signal");
808 	}
809 }
810 
811 static const struct got_error *
812 ensure_proc_is_reading(struct gotd_client *client,
813     struct gotd_child_proc *proc)
814 {
815 	if (!client_is_reading(client)) {
816 		kill_proc(proc, 1);
817 		return got_error_fmt(GOT_ERR_BAD_PACKET,
818 		    "PID %d handled a read-request for uid %d but this "
819 		    "user is not reading from a repository", proc->pid,
820 		    client->euid);
821 	}
822 
823 	return NULL;
824 }
825 
826 static const struct got_error *
827 ensure_proc_is_writing(struct gotd_client *client,
828     struct gotd_child_proc *proc)
829 {
830 	if (!client_is_writing(client)) {
831 		kill_proc(proc, 1);
832 		return got_error_fmt(GOT_ERR_BAD_PACKET,
833 		    "PID %d handled a write-request for uid %d but this "
834 		    "user is not writing to a repository", proc->pid,
835 		    client->euid);
836 	}
837 
838 	return NULL;
839 }
840 
841 static int
842 verify_imsg_src(struct gotd_client *client, struct gotd_child_proc *proc,
843     struct imsg *imsg)
844 {
845 	const struct got_error *err;
846 	int ret = 0;
847 
848 	if (proc->type == PROC_REPO_READ || proc->type == PROC_REPO_WRITE) {
849 		if (client->repo == NULL)
850 			fatalx("no process found for uid %d", client->euid);
851 		if (proc->pid != client->repo->pid) {
852 			kill_proc(proc, 1);
853 			log_warnx("received message from PID %d for uid %d, "
854 			    "while PID %d is the process serving this user",
855 			    proc->pid, client->euid, client->repo->pid);
856 			return 0;
857 		}
858 	}
859 	if (proc->type == PROC_SESSION) {
860 		if (client->session == NULL) {
861 			log_warnx("no session found for uid %d", client->euid);
862 			return 0;
863 		}
864 		if (proc->pid != client->session->pid) {
865 			kill_proc(proc, 1);
866 			log_warnx("received message from PID %d for uid %d, "
867 			    "while PID %d is the process serving this user",
868 			    proc->pid, client->euid, client->session->pid);
869 			return 0;
870 		}
871 	}
872 
873 	switch (imsg->hdr.type) {
874 	case GOTD_IMSG_ERROR:
875 		ret = 1;
876 		break;
877 	case GOTD_IMSG_CONNECT:
878 		if (proc->type != PROC_LISTEN) {
879 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
880 			    "new connection for uid %d from PID %d "
881 			    "which is not the listen process",
882 			    proc->pid, client->euid);
883 		} else
884 			ret = 1;
885 		break;
886 	case GOTD_IMSG_ACCESS_GRANTED:
887 		if (proc->type != PROC_AUTH) {
888 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
889 			    "authentication of uid %d from PID %d "
890 			    "which is not the auth process",
891 			    proc->pid, client->euid);
892 		} else
893 			ret = 1;
894 		break;
895 	case GOTD_IMSG_CLIENT_SESSION_READY:
896 		if (proc->type != PROC_SESSION) {
897 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
898 			    "unexpected \"ready\" signal from PID %d",
899 			    proc->pid);
900 		} else
901 			ret = 1;
902 		break;
903 	case GOTD_IMSG_REPO_CHILD_READY:
904 		if (proc->type != PROC_REPO_READ &&
905 		    proc->type != PROC_REPO_WRITE) {
906 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
907 			    "unexpected \"ready\" signal from PID %d",
908 			    proc->pid);
909 		} else
910 			ret = 1;
911 		break;
912 	case GOTD_IMSG_PACKFILE_DONE:
913 		err = ensure_proc_is_reading(client, proc);
914 		if (err)
915 			log_warnx("uid %d: %s", client->euid, err->msg);
916 		else
917 			ret = 1;
918 		break;
919 	case GOTD_IMSG_PACKFILE_INSTALL:
920 	case GOTD_IMSG_REF_UPDATES_START:
921 	case GOTD_IMSG_REF_UPDATE:
922 		err = ensure_proc_is_writing(client, proc);
923 		if (err)
924 			log_warnx("uid %d: %s", client->euid, err->msg);
925 		else
926 			ret = 1;
927 		break;
928 	default:
929 		log_debug("%s: unexpected imsg %d", __func__, imsg->hdr.type);
930 		break;
931 	}
932 
933 	return ret;
934 }
935 
936 static const struct got_error *
937 connect_repo_child(struct gotd_client *client,
938     struct gotd_child_proc *repo_proc)
939 {
940 	static const struct got_error *err;
941 	struct gotd_imsgev *session_iev = &client->session->iev;
942 	struct gotd_imsg_connect_repo_child ireq;
943 	int pipe[2];
944 
945 	if (client->state != GOTD_CLIENT_STATE_ACCESS_GRANTED)
946 		return got_error_msg(GOT_ERR_BAD_REQUEST,
947 		    "unexpected repo child ready signal received");
948 
949 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
950 	    PF_UNSPEC, pipe) == -1)
951 		fatal("socketpair");
952 
953 	memset(&ireq, 0, sizeof(ireq));
954 	ireq.client_id = client->id;
955 	ireq.proc_id = repo_proc->type;
956 
957 	/* Pass repo child pipe to session child process. */
958 	if (gotd_imsg_compose_event(session_iev, GOTD_IMSG_CONNECT_REPO_CHILD,
959 	    PROC_GOTD, pipe[0], &ireq, sizeof(ireq)) == -1) {
960 		err = got_error_from_errno("imsg compose CONNECT_REPO_CHILD");
961 		close(pipe[0]);
962 		close(pipe[1]);
963 		return err;
964 	}
965 
966 	/* Pass session child pipe to repo child process. */
967 	if (gotd_imsg_compose_event(&repo_proc->iev,
968 	    GOTD_IMSG_CONNECT_REPO_CHILD, PROC_GOTD, pipe[1], NULL, 0) == -1) {
969 		err = got_error_from_errno("imsg compose CONNECT_REPO_CHILD");
970 		close(pipe[1]);
971 		return err;
972 	}
973 
974 	return NULL;
975 }
976 
977 static void
978 gotd_dispatch_listener(int fd, short event, void *arg)
979 {
980 	struct gotd_imsgev *iev = arg;
981 	struct imsgbuf *ibuf = &iev->ibuf;
982 	struct gotd_child_proc *proc = &gotd.listen_proc;
983 	ssize_t n;
984 	int shut = 0;
985 	struct imsg imsg;
986 
987 	if (proc->iev.ibuf.fd != fd)
988 		fatalx("%s: unexpected fd %d", __func__, fd);
989 
990 	if (event & EV_READ) {
991 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
992 			fatal("imsg_read error");
993 		if (n == 0) {
994 			/* Connection closed. */
995 			shut = 1;
996 			goto done;
997 		}
998 	}
999 
1000 	if (event & EV_WRITE) {
1001 		n = msgbuf_write(&ibuf->w);
1002 		if (n == -1 && errno != EAGAIN)
1003 			fatal("msgbuf_write");
1004 		if (n == 0) {
1005 			/* Connection closed. */
1006 			shut = 1;
1007 			goto done;
1008 		}
1009 	}
1010 
1011 	for (;;) {
1012 		const struct got_error *err = NULL;
1013 		struct gotd_client *client = NULL;
1014 		uint32_t client_id = 0;
1015 		int do_disconnect = 0;
1016 
1017 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1018 			fatal("%s: imsg_get error", __func__);
1019 		if (n == 0)	/* No more messages. */
1020 			break;
1021 
1022 		switch (imsg.hdr.type) {
1023 		case GOTD_IMSG_ERROR:
1024 			do_disconnect = 1;
1025 			err = gotd_imsg_recv_error(&client_id, &imsg);
1026 			break;
1027 		case GOTD_IMSG_CONNECT:
1028 			err = recv_connect(&client_id, &imsg);
1029 			break;
1030 		default:
1031 			log_debug("unexpected imsg %d", imsg.hdr.type);
1032 			break;
1033 		}
1034 
1035 		client = find_client(client_id);
1036 		if (client == NULL) {
1037 			log_warnx("%s: client not found", __func__);
1038 			imsg_free(&imsg);
1039 			continue;
1040 		}
1041 
1042 		if (err)
1043 			log_warnx("uid %d: %s", client->euid, err->msg);
1044 
1045 		if (do_disconnect) {
1046 			if (err)
1047 				disconnect_on_error(client, err);
1048 			else
1049 				disconnect(client);
1050 		}
1051 
1052 		imsg_free(&imsg);
1053 	}
1054 done:
1055 	if (!shut) {
1056 		gotd_imsg_event_add(iev);
1057 	} else {
1058 		/* This pipe is dead. Remove its event handler */
1059 		event_del(&iev->ev);
1060 		event_loopexit(NULL);
1061 	}
1062 }
1063 
1064 static void
1065 gotd_dispatch_auth_child(int fd, short event, void *arg)
1066 {
1067 	const struct got_error *err = NULL;
1068 	struct gotd_imsgev *iev = arg;
1069 	struct imsgbuf *ibuf = &iev->ibuf;
1070 	struct gotd_client *client;
1071 	struct gotd_repo *repo = NULL;
1072 	ssize_t n;
1073 	int shut = 0;
1074 	struct imsg imsg;
1075 	uint32_t client_id = 0;
1076 	int do_disconnect = 0;
1077 
1078 	client = find_client_by_proc_fd(fd);
1079 	if (client == NULL)
1080 		fatalx("cannot find client for fd %d", fd);
1081 
1082 	if (client->auth == NULL)
1083 		fatalx("cannot find auth child process for fd %d", fd);
1084 
1085 	if (event & EV_READ) {
1086 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1087 			fatal("imsg_read error");
1088 		if (n == 0) {
1089 			/* Connection closed. */
1090 			shut = 1;
1091 			goto done;
1092 		}
1093 	}
1094 
1095 	if (event & EV_WRITE) {
1096 		n = msgbuf_write(&ibuf->w);
1097 		if (n == -1 && errno != EAGAIN)
1098 			fatal("msgbuf_write");
1099 		if (n == 0) {
1100 			/* Connection closed. */
1101 			shut = 1;
1102 		}
1103 		goto done;
1104 	}
1105 
1106 	if (client->auth->iev.ibuf.fd != fd)
1107 		fatalx("%s: unexpected fd %d", __func__, fd);
1108 
1109 	if ((n = imsg_get(ibuf, &imsg)) == -1)
1110 		fatal("%s: imsg_get error", __func__);
1111 	if (n == 0)	/* No more messages. */
1112 		return;
1113 
1114 	evtimer_del(&client->tmo);
1115 
1116 	switch (imsg.hdr.type) {
1117 	case GOTD_IMSG_ERROR:
1118 		do_disconnect = 1;
1119 		err = gotd_imsg_recv_error(&client_id, &imsg);
1120 		break;
1121 	case GOTD_IMSG_ACCESS_GRANTED:
1122 		client->state = GOTD_CLIENT_STATE_ACCESS_GRANTED;
1123 		break;
1124 	default:
1125 		do_disconnect = 1;
1126 		log_debug("unexpected imsg %d", imsg.hdr.type);
1127 		break;
1128 	}
1129 
1130 	if (!verify_imsg_src(client, client->auth, &imsg)) {
1131 		do_disconnect = 1;
1132 		log_debug("dropping imsg type %d from PID %d",
1133 		    imsg.hdr.type, client->auth->pid);
1134 	}
1135 	imsg_free(&imsg);
1136 
1137 	if (do_disconnect) {
1138 		if (err)
1139 			disconnect_on_error(client, err);
1140 		else
1141 			disconnect(client);
1142 		goto done;
1143 	}
1144 
1145 	repo = find_repo_by_name(client->auth->repo_name);
1146 	if (repo == NULL) {
1147 		err = got_error(GOT_ERR_NOT_GIT_REPO);
1148 		goto done;
1149 	}
1150 	kill_auth_proc(client);
1151 
1152 	log_info("authenticated uid %d for repository %s",
1153 	    client->euid, repo->name);
1154 
1155 	err = start_session_child(client, repo, gotd.argv0,
1156 	    gotd.confpath, gotd.daemonize, gotd.verbosity);
1157 	if (err)
1158 		goto done;
1159 done:
1160 	if (err)
1161 		log_warnx("uid %d: %s", client->euid, err->msg);
1162 
1163 	/* We might have killed the auth process by now. */
1164 	if (client->auth != NULL) {
1165 		if (!shut) {
1166 			gotd_imsg_event_add(iev);
1167 		} else {
1168 			/* This pipe is dead. Remove its event handler */
1169 			event_del(&iev->ev);
1170 		}
1171 	}
1172 }
1173 
1174 static const struct got_error *
1175 connect_session(struct gotd_client *client)
1176 {
1177 	const struct got_error *err = NULL;
1178 	struct gotd_imsg_connect iconnect;
1179 	int s;
1180 
1181 	memset(&iconnect, 0, sizeof(iconnect));
1182 
1183 	s = dup(client->fd);
1184 	if (s == -1)
1185 		return got_error_from_errno("dup");
1186 
1187 	iconnect.client_id = client->id;
1188 	iconnect.euid = client->euid;
1189 	iconnect.egid = client->egid;
1190 
1191 	if (gotd_imsg_compose_event(&client->session->iev, GOTD_IMSG_CONNECT,
1192 	    PROC_GOTD, s, &iconnect, sizeof(iconnect)) == -1) {
1193 		err = got_error_from_errno("imsg compose CONNECT");
1194 		close(s);
1195 		return err;
1196 	}
1197 
1198 	/*
1199 	 * We are no longer interested in messages from this client.
1200 	 * Further client requests will be handled by the session process.
1201 	 */
1202 	msgbuf_clear(&client->iev.ibuf.w);
1203 	imsg_clear(&client->iev.ibuf);
1204 	event_del(&client->iev.ev);
1205 	client->fd = -1; /* will be closed via copy in client->iev.ibuf.fd */
1206 
1207 	return NULL;
1208 }
1209 
1210 static void
1211 gotd_dispatch_client_session(int fd, short event, void *arg)
1212 {
1213 	struct gotd_imsgev *iev = arg;
1214 	struct imsgbuf *ibuf = &iev->ibuf;
1215 	struct gotd_child_proc *proc = NULL;
1216 	struct gotd_client *client = NULL;
1217 	ssize_t n;
1218 	int shut = 0;
1219 	struct imsg imsg;
1220 
1221 	client = find_client_by_proc_fd(fd);
1222 	if (client == NULL)
1223 		fatalx("cannot find client for fd %d", fd);
1224 
1225 	if (event & EV_READ) {
1226 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1227 			fatal("imsg_read error");
1228 		if (n == 0) {
1229 			/* Connection closed. */
1230 			shut = 1;
1231 			goto done;
1232 		}
1233 	}
1234 
1235 	if (event & EV_WRITE) {
1236 		n = msgbuf_write(&ibuf->w);
1237 		if (n == -1 && errno != EAGAIN)
1238 			fatal("msgbuf_write");
1239 		if (n == 0) {
1240 			/* Connection closed. */
1241 			shut = 1;
1242 			goto done;
1243 		}
1244 	}
1245 
1246 	proc = client->session;
1247 	if (proc == NULL)
1248 		fatalx("cannot find session child process for fd %d", fd);
1249 
1250 	for (;;) {
1251 		const struct got_error *err = NULL;
1252 		uint32_t client_id = 0;
1253 		int do_disconnect = 0, do_start_repo_child = 0;
1254 
1255 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1256 			fatal("%s: imsg_get error", __func__);
1257 		if (n == 0)	/* No more messages. */
1258 			break;
1259 
1260 		switch (imsg.hdr.type) {
1261 		case GOTD_IMSG_ERROR:
1262 			do_disconnect = 1;
1263 			err = gotd_imsg_recv_error(&client_id, &imsg);
1264 			break;
1265 		case GOTD_IMSG_CLIENT_SESSION_READY:
1266 			if (client->state != GOTD_CLIENT_STATE_ACCESS_GRANTED) {
1267 				err = got_error(GOT_ERR_PRIVSEP_MSG);
1268 				break;
1269 			}
1270 			do_start_repo_child = 1;
1271 			break;
1272 		case GOTD_IMSG_DISCONNECT:
1273 			do_disconnect = 1;
1274 			break;
1275 		default:
1276 			log_debug("unexpected imsg %d", imsg.hdr.type);
1277 			break;
1278 		}
1279 
1280 		if (!verify_imsg_src(client, proc, &imsg)) {
1281 			log_debug("dropping imsg type %d from PID %d",
1282 			    imsg.hdr.type, proc->pid);
1283 			imsg_free(&imsg);
1284 			continue;
1285 		}
1286 		if (err)
1287 			log_warnx("uid %d: %s", client->euid, err->msg);
1288 
1289 		if (do_start_repo_child) {
1290 			struct gotd_repo *repo;
1291 
1292 			repo = find_repo_by_name(client->session->repo_name);
1293 			if (repo != NULL) {
1294 				enum gotd_procid proc_type;
1295 
1296 				if (client->required_auth & GOTD_AUTH_WRITE)
1297 					proc_type = PROC_REPO_WRITE;
1298 				else
1299 					proc_type = PROC_REPO_READ;
1300 
1301 				err = start_repo_child(client, proc_type, repo,
1302 				    gotd.argv0, gotd.confpath, gotd.daemonize,
1303 				    gotd.verbosity);
1304 			} else
1305 				err = got_error(GOT_ERR_NOT_GIT_REPO);
1306 
1307 			if (err) {
1308 				log_warnx("uid %d: %s", client->euid, err->msg);
1309 				do_disconnect = 1;
1310 			}
1311 		}
1312 
1313 		if (do_disconnect) {
1314 			if (err)
1315 				disconnect_on_error(client, err);
1316 			else
1317 				disconnect(client);
1318 		}
1319 
1320 		imsg_free(&imsg);
1321 	}
1322 done:
1323 	if (!shut) {
1324 		gotd_imsg_event_add(iev);
1325 	} else {
1326 		/* This pipe is dead. Remove its event handler */
1327 		event_del(&iev->ev);
1328 		disconnect(client);
1329 	}
1330 }
1331 
1332 static void
1333 gotd_dispatch_repo_child(int fd, short event, void *arg)
1334 {
1335 	struct gotd_imsgev *iev = arg;
1336 	struct imsgbuf *ibuf = &iev->ibuf;
1337 	struct gotd_child_proc *proc = NULL;
1338 	struct gotd_client *client;
1339 	ssize_t n;
1340 	int shut = 0;
1341 	struct imsg imsg;
1342 
1343 	client = find_client_by_proc_fd(fd);
1344 	if (client == NULL)
1345 		fatalx("cannot find client for fd %d", fd);
1346 
1347 	if (event & EV_READ) {
1348 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1349 			fatal("imsg_read error");
1350 		if (n == 0) {
1351 			/* Connection closed. */
1352 			shut = 1;
1353 			goto done;
1354 		}
1355 	}
1356 
1357 	if (event & EV_WRITE) {
1358 		n = msgbuf_write(&ibuf->w);
1359 		if (n == -1 && errno != EAGAIN)
1360 			fatal("msgbuf_write");
1361 		if (n == 0) {
1362 			/* Connection closed. */
1363 			shut = 1;
1364 			goto done;
1365 		}
1366 	}
1367 
1368 	proc = client->repo;
1369 	if (proc == NULL)
1370 		fatalx("cannot find child process for fd %d", fd);
1371 
1372 	for (;;) {
1373 		const struct got_error *err = NULL;
1374 		uint32_t client_id = 0;
1375 		int do_disconnect = 0;
1376 
1377 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1378 			fatal("%s: imsg_get error", __func__);
1379 		if (n == 0)	/* No more messages. */
1380 			break;
1381 
1382 		switch (imsg.hdr.type) {
1383 		case GOTD_IMSG_ERROR:
1384 			do_disconnect = 1;
1385 			err = gotd_imsg_recv_error(&client_id, &imsg);
1386 			break;
1387 		case GOTD_IMSG_REPO_CHILD_READY:
1388 			err = connect_session(client);
1389 			if (err)
1390 				break;
1391 			err = connect_repo_child(client, proc);
1392 			break;
1393 		default:
1394 			log_debug("unexpected imsg %d", imsg.hdr.type);
1395 			break;
1396 		}
1397 
1398 		if (!verify_imsg_src(client, proc, &imsg)) {
1399 			log_debug("dropping imsg type %d from PID %d",
1400 			    imsg.hdr.type, proc->pid);
1401 			imsg_free(&imsg);
1402 			continue;
1403 		}
1404 		if (err)
1405 			log_warnx("uid %d: %s", client->euid, err->msg);
1406 
1407 		if (do_disconnect) {
1408 			if (err)
1409 				disconnect_on_error(client, err);
1410 			else
1411 				disconnect(client);
1412 		}
1413 
1414 		imsg_free(&imsg);
1415 	}
1416 done:
1417 	if (!shut) {
1418 		gotd_imsg_event_add(iev);
1419 	} else {
1420 		/* This pipe is dead. Remove its event handler */
1421 		event_del(&iev->ev);
1422 		disconnect(client);
1423 	}
1424 }
1425 
1426 static pid_t
1427 start_child(enum gotd_procid proc_id, const char *repo_path,
1428     char *argv0, const char *confpath, int fd, int daemonize, int verbosity)
1429 {
1430 	char	*argv[11];
1431 	int	 argc = 0;
1432 	pid_t	 pid;
1433 
1434 	switch (pid = fork()) {
1435 	case -1:
1436 		fatal("cannot fork");
1437 	case 0:
1438 		break;
1439 	default:
1440 		close(fd);
1441 		return pid;
1442 	}
1443 
1444 	if (fd != GOTD_FILENO_MSG_PIPE) {
1445 		if (dup2(fd, GOTD_FILENO_MSG_PIPE) == -1)
1446 			fatal("cannot setup imsg fd");
1447 	} else if (fcntl(fd, F_SETFD, 0) == -1)
1448 		fatal("cannot setup imsg fd");
1449 
1450 	argv[argc++] = argv0;
1451 	switch (proc_id) {
1452 	case PROC_LISTEN:
1453 		argv[argc++] = (char *)"-L";
1454 		break;
1455 	case PROC_AUTH:
1456 		argv[argc++] = (char *)"-A";
1457 		break;
1458 	case PROC_SESSION:
1459 		argv[argc++] = (char *)"-S";
1460 		break;
1461 	case PROC_REPO_READ:
1462 		argv[argc++] = (char *)"-R";
1463 		break;
1464 	case PROC_REPO_WRITE:
1465 		argv[argc++] = (char *)"-W";
1466 		break;
1467 	default:
1468 		fatalx("invalid process id %d", proc_id);
1469 	}
1470 
1471 	argv[argc++] = (char *)"-f";
1472 	argv[argc++] = (char *)confpath;
1473 
1474 	if (repo_path) {
1475 		argv[argc++] = (char *)"-P";
1476 		argv[argc++] = (char *)repo_path;
1477 	}
1478 
1479 	if (!daemonize)
1480 		argv[argc++] = (char *)"-d";
1481 	if (verbosity > 0)
1482 		argv[argc++] = (char *)"-v";
1483 	if (verbosity > 1)
1484 		argv[argc++] = (char *)"-v";
1485 	argv[argc++] = NULL;
1486 
1487 	execvp(argv0, argv);
1488 	fatal("execvp");
1489 }
1490 
1491 static void
1492 start_listener(char *argv0, const char *confpath, int daemonize, int verbosity)
1493 {
1494 	struct gotd_child_proc *proc = &gotd.listen_proc;
1495 
1496 	proc->type = PROC_LISTEN;
1497 
1498 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1499 	    PF_UNSPEC, proc->pipe) == -1)
1500 		fatal("socketpair");
1501 
1502 	proc->pid = start_child(proc->type, NULL, argv0, confpath,
1503 	    proc->pipe[1], daemonize, verbosity);
1504 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1505 	proc->iev.handler = gotd_dispatch_listener;
1506 	proc->iev.events = EV_READ;
1507 	proc->iev.handler_arg = NULL;
1508 }
1509 
1510 static const struct got_error *
1511 start_session_child(struct gotd_client *client, struct gotd_repo *repo,
1512     char *argv0, const char *confpath, int daemonize, int verbosity)
1513 {
1514 	struct gotd_child_proc *proc;
1515 
1516 	proc = calloc(1, sizeof(*proc));
1517 	if (proc == NULL)
1518 		return got_error_from_errno("calloc");
1519 
1520 	proc->type = PROC_SESSION;
1521 	if (strlcpy(proc->repo_name, repo->name,
1522 	    sizeof(proc->repo_name)) >= sizeof(proc->repo_name))
1523 		fatalx("repository name too long: %s", repo->name);
1524 	log_debug("starting client uid %d session for repository %s",
1525 	    client->euid, repo->name);
1526 	if (strlcpy(proc->repo_path, repo->path, sizeof(proc->repo_path)) >=
1527 	    sizeof(proc->repo_path))
1528 		fatalx("repository path too long: %s", repo->path);
1529 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1530 	    PF_UNSPEC, proc->pipe) == -1)
1531 		fatal("socketpair");
1532 	proc->pid = start_child(proc->type, proc->repo_path, argv0,
1533 	    confpath, proc->pipe[1], daemonize, verbosity);
1534 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1535 	log_debug("proc %s %s is on fd %d",
1536 	    gotd_proc_names[proc->type], proc->repo_path,
1537 	    proc->pipe[0]);
1538 	proc->iev.handler = gotd_dispatch_client_session;
1539 	proc->iev.events = EV_READ;
1540 	proc->iev.handler_arg = NULL;
1541 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1542 	    gotd_dispatch_client_session, &proc->iev);
1543 	gotd_imsg_event_add(&proc->iev);
1544 
1545 	client->session = proc;
1546 	return NULL;
1547 }
1548 
1549 static const struct got_error *
1550 start_repo_child(struct gotd_client *client, enum gotd_procid proc_type,
1551     struct gotd_repo *repo, char *argv0, const char *confpath,
1552     int daemonize, int verbosity)
1553 {
1554 	struct gotd_child_proc *proc;
1555 
1556 	if (proc_type != PROC_REPO_READ && proc_type != PROC_REPO_WRITE)
1557 		return got_error_msg(GOT_ERR_NOT_IMPL, "bad process type");
1558 
1559 	proc = calloc(1, sizeof(*proc));
1560 	if (proc == NULL)
1561 		return got_error_from_errno("calloc");
1562 
1563 	proc->type = proc_type;
1564 	if (strlcpy(proc->repo_name, repo->name,
1565 	    sizeof(proc->repo_name)) >= sizeof(proc->repo_name))
1566 		fatalx("repository name too long: %s", repo->name);
1567 	log_debug("starting %s for repository %s",
1568 	    proc->type == PROC_REPO_READ ? "reader" : "writer", repo->name);
1569 	if (strlcpy(proc->repo_path, repo->path, sizeof(proc->repo_path)) >=
1570 	    sizeof(proc->repo_path))
1571 		fatalx("repository path too long: %s", repo->path);
1572 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1573 	    PF_UNSPEC, proc->pipe) == -1)
1574 		fatal("socketpair");
1575 	proc->pid = start_child(proc->type, proc->repo_path, argv0,
1576 	    confpath, proc->pipe[1], daemonize, verbosity);
1577 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1578 	log_debug("proc %s %s is on fd %d",
1579 	    gotd_proc_names[proc->type], proc->repo_path,
1580 	    proc->pipe[0]);
1581 	proc->iev.handler = gotd_dispatch_repo_child;
1582 	proc->iev.events = EV_READ;
1583 	proc->iev.handler_arg = NULL;
1584 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1585 	    gotd_dispatch_repo_child, &proc->iev);
1586 	gotd_imsg_event_add(&proc->iev);
1587 
1588 	client->repo = proc;
1589 	return NULL;
1590 }
1591 
1592 static const struct got_error *
1593 start_auth_child(struct gotd_client *client, int required_auth,
1594     struct gotd_repo *repo, char *argv0, const char *confpath,
1595     int daemonize, int verbosity)
1596 {
1597 	const struct got_error *err = NULL;
1598 	struct gotd_child_proc *proc;
1599 	struct gotd_imsg_auth iauth;
1600 	int fd;
1601 
1602 	memset(&iauth, 0, sizeof(iauth));
1603 
1604 	fd = dup(client->fd);
1605 	if (fd == -1)
1606 		return got_error_from_errno("dup");
1607 
1608 	proc = calloc(1, sizeof(*proc));
1609 	if (proc == NULL) {
1610 		err = got_error_from_errno("calloc");
1611 		close(fd);
1612 		return err;
1613 	}
1614 
1615 	proc->type = PROC_AUTH;
1616 	if (strlcpy(proc->repo_name, repo->name,
1617 	    sizeof(proc->repo_name)) >= sizeof(proc->repo_name))
1618 		fatalx("repository name too long: %s", repo->name);
1619 	log_debug("starting auth for uid %d repository %s",
1620 	    client->euid, repo->name);
1621 	if (strlcpy(proc->repo_path, repo->path, sizeof(proc->repo_path)) >=
1622 	    sizeof(proc->repo_path))
1623 		fatalx("repository path too long: %s", repo->path);
1624 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1625 	    PF_UNSPEC, proc->pipe) == -1)
1626 		fatal("socketpair");
1627 	proc->pid = start_child(proc->type, proc->repo_path, argv0,
1628 	    confpath, proc->pipe[1], daemonize, verbosity);
1629 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1630 	log_debug("proc %s %s is on fd %d",
1631 	    gotd_proc_names[proc->type], proc->repo_path,
1632 	    proc->pipe[0]);
1633 	proc->iev.handler = gotd_dispatch_auth_child;
1634 	proc->iev.events = EV_READ;
1635 	proc->iev.handler_arg = NULL;
1636 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1637 	    gotd_dispatch_auth_child, &proc->iev);
1638 	gotd_imsg_event_add(&proc->iev);
1639 
1640 	iauth.euid = client->euid;
1641 	iauth.egid = client->egid;
1642 	iauth.required_auth = required_auth;
1643 	iauth.client_id = client->id;
1644 	if (gotd_imsg_compose_event(&proc->iev, GOTD_IMSG_AUTHENTICATE,
1645 	    PROC_GOTD, fd, &iauth, sizeof(iauth)) == -1) {
1646 		log_warn("imsg compose AUTHENTICATE");
1647 		close(fd);
1648 		/* Let the auth_timeout handler tidy up. */
1649 	}
1650 
1651 	client->auth = proc;
1652 	client->required_auth = required_auth;
1653 	return NULL;
1654 }
1655 
1656 static void
1657 apply_unveil_repo_readonly(const char *repo_path)
1658 {
1659 	if (unveil(repo_path, "r") == -1)
1660 		fatal("unveil %s", repo_path);
1661 
1662 	if (unveil(NULL, NULL) == -1)
1663 		fatal("unveil");
1664 }
1665 
1666 static void
1667 apply_unveil_repo_readwrite(const char *repo_path)
1668 {
1669 	if (unveil(repo_path, "rwc") == -1)
1670 		fatal("unveil %s", repo_path);
1671 
1672 	if (unveil(GOT_TMPDIR_STR, "rwc") == -1)
1673 		fatal("unveil %s", GOT_TMPDIR_STR);
1674 
1675 	if (unveil(NULL, NULL) == -1)
1676 		fatal("unveil");
1677 }
1678 
1679 static void
1680 apply_unveil_none(void)
1681 {
1682 	if (unveil("/", "") == -1)
1683 		fatal("unveil");
1684 
1685 	if (unveil(NULL, NULL) == -1)
1686 		fatal("unveil");
1687 }
1688 
1689 static void
1690 apply_unveil_selfexec(void)
1691 {
1692 	if (unveil(gotd.argv0, "x") == -1)
1693 		fatal("unveil %s", gotd.argv0);
1694 
1695 	if (unveil(NULL, NULL) == -1)
1696 		fatal("unveil");
1697 }
1698 
1699 int
1700 main(int argc, char **argv)
1701 {
1702 	const struct got_error *error = NULL;
1703 	int ch, fd = -1, daemonize = 1, verbosity = 0, noaction = 0;
1704 	const char *confpath = GOTD_CONF_PATH;
1705 	char *argv0 = argv[0];
1706 	char title[2048];
1707 	struct passwd *pw = NULL;
1708 	char *repo_path = NULL;
1709 	enum gotd_procid proc_id = PROC_GOTD;
1710 	struct event evsigint, evsigterm, evsighup, evsigusr1;
1711 	int *pack_fds = NULL, *temp_fds = NULL;
1712 
1713 	log_init(1, LOG_DAEMON); /* Log to stderr until daemonized. */
1714 
1715 	while ((ch = getopt(argc, argv, "Adf:LnP:RSvW")) != -1) {
1716 		switch (ch) {
1717 		case 'A':
1718 			proc_id = PROC_AUTH;
1719 			break;
1720 		case 'd':
1721 			daemonize = 0;
1722 			break;
1723 		case 'f':
1724 			confpath = optarg;
1725 			break;
1726 		case 'L':
1727 			proc_id = PROC_LISTEN;
1728 			break;
1729 		case 'n':
1730 			noaction = 1;
1731 			break;
1732 		case 'P':
1733 			repo_path = realpath(optarg, NULL);
1734 			if (repo_path == NULL)
1735 				fatal("realpath '%s'", optarg);
1736 			break;
1737 		case 'R':
1738 			proc_id = PROC_REPO_READ;
1739 			break;
1740 		case 'S':
1741 			proc_id = PROC_SESSION;
1742 			break;
1743 		case 'v':
1744 			if (verbosity < 3)
1745 				verbosity++;
1746 			break;
1747 		case 'W':
1748 			proc_id = PROC_REPO_WRITE;
1749 			break;
1750 		default:
1751 			usage();
1752 		}
1753 	}
1754 
1755 	argc -= optind;
1756 	argv += optind;
1757 
1758 	if (argc != 0)
1759 		usage();
1760 
1761 	if (geteuid() && (proc_id == PROC_GOTD || proc_id == PROC_LISTEN))
1762 		fatalx("need root privileges");
1763 
1764 	if (parse_config(confpath, proc_id, &gotd) != 0)
1765 		return 1;
1766 
1767 	pw = getpwnam(gotd.user_name);
1768 	if (pw == NULL)
1769 		fatalx("user %s not found", gotd.user_name);
1770 
1771 	if (pw->pw_uid == 0)
1772 		fatalx("cannot run %s as the superuser", getprogname());
1773 
1774 	if (noaction) {
1775 		fprintf(stderr, "configuration OK\n");
1776 		return 0;
1777 	}
1778 
1779 	gotd.argv0 = argv0;
1780 	gotd.daemonize = daemonize;
1781 	gotd.verbosity = verbosity;
1782 	gotd.confpath = confpath;
1783 
1784 	/* Require an absolute path in argv[0] for reliable re-exec. */
1785 	if (!got_path_is_absolute(argv0))
1786 		fatalx("bad path \"%s\": must be an absolute path", argv0);
1787 
1788 	log_init(daemonize ? 0 : 1, LOG_DAEMON);
1789 	log_setverbose(verbosity);
1790 
1791 	if (proc_id == PROC_GOTD) {
1792 		snprintf(title, sizeof(title), "%s", gotd_proc_names[proc_id]);
1793 		arc4random_buf(&clients_hash_key, sizeof(clients_hash_key));
1794 		if (daemonize && daemon(1, 0) == -1)
1795 			fatal("daemon");
1796 		gotd.pid = getpid();
1797 		start_listener(argv0, confpath, daemonize, verbosity);
1798 	} else if (proc_id == PROC_LISTEN) {
1799 		snprintf(title, sizeof(title), "%s", gotd_proc_names[proc_id]);
1800 		if (verbosity) {
1801 			log_info("socket: %s", gotd.unix_socket_path);
1802 			log_info("user: %s", pw->pw_name);
1803 		}
1804 
1805 		fd = unix_socket_listen(gotd.unix_socket_path, pw->pw_uid,
1806 		    pw->pw_gid);
1807 		if (fd == -1) {
1808 			fatal("cannot listen on unix socket %s",
1809 			    gotd.unix_socket_path);
1810 		}
1811 	} else if (proc_id == PROC_AUTH) {
1812 		snprintf(title, sizeof(title), "%s %s",
1813 		    gotd_proc_names[proc_id], repo_path);
1814 	} else if (proc_id == PROC_REPO_READ || proc_id == PROC_REPO_WRITE ||
1815 	    proc_id == PROC_SESSION) {
1816 		error = got_repo_pack_fds_open(&pack_fds);
1817 		if (error != NULL)
1818 			fatalx("cannot open pack tempfiles: %s", error->msg);
1819 		error = got_repo_temp_fds_open(&temp_fds);
1820 		if (error != NULL)
1821 			fatalx("cannot open pack tempfiles: %s", error->msg);
1822 		if (repo_path == NULL)
1823 			fatalx("repository path not specified");
1824 		snprintf(title, sizeof(title), "%s %s",
1825 		    gotd_proc_names[proc_id], repo_path);
1826 	} else
1827 		fatal("invalid process id %d", proc_id);
1828 
1829 	setproctitle("%s", title);
1830 	log_procinit(title);
1831 
1832 	/* Drop root privileges. */
1833 	if (setgid(pw->pw_gid) == -1)
1834 		fatal("setgid %d failed", pw->pw_gid);
1835 	if (setuid(pw->pw_uid) == -1)
1836 		fatal("setuid %d failed", pw->pw_uid);
1837 
1838 	event_init();
1839 
1840 	switch (proc_id) {
1841 	case PROC_GOTD:
1842 #ifndef PROFILE
1843 		/* "exec" promise will be limited to argv[0] via unveil(2). */
1844 		if (pledge("stdio proc exec sendfd recvfd unveil", NULL) == -1)
1845 			err(1, "pledge");
1846 #endif
1847 		break;
1848 	case PROC_LISTEN:
1849 #ifndef PROFILE
1850 		if (pledge("stdio sendfd unix unveil", NULL) == -1)
1851 			err(1, "pledge");
1852 #endif
1853 		/*
1854 		 * Ensure that AF_UNIX bind(2) cannot be used with any other
1855 		 * sockets by revoking all filesystem access via unveil(2).
1856 		 */
1857 		apply_unveil_none();
1858 
1859 		listen_main(title, fd, gotd.connection_limits,
1860 		    gotd.nconnection_limits);
1861 		/* NOTREACHED */
1862 		break;
1863 	case PROC_AUTH:
1864 #ifndef PROFILE
1865 		if (pledge("stdio getpw recvfd unix unveil", NULL) == -1)
1866 			err(1, "pledge");
1867 #endif
1868 		/*
1869 		 * We need the "unix" pledge promise for getpeername(2) only.
1870 		 * Ensure that AF_UNIX bind(2) cannot be used by revoking all
1871 		 * filesystem access via unveil(2). Access to password database
1872 		 * files will still work since "getpw" bypasses unveil(2).
1873 		 */
1874 		apply_unveil_none();
1875 
1876 		auth_main(title, &gotd.repos, repo_path);
1877 		/* NOTREACHED */
1878 		break;
1879 	case PROC_SESSION:
1880 #ifndef PROFILE
1881 		/*
1882 		 * The "recvfd" promise is only needed during setup and
1883 		 * will be removed in a later pledge(2) call.
1884 		 */
1885 		if (pledge("stdio rpath wpath cpath recvfd sendfd fattr flock "
1886 		    "unveil", NULL) == -1)
1887 			err(1, "pledge");
1888 #endif
1889 		apply_unveil_repo_readwrite(repo_path);
1890 		session_main(title, repo_path, pack_fds, temp_fds,
1891 		    &gotd.request_timeout);
1892 		/* NOTREACHED */
1893 		break;
1894 	case PROC_REPO_READ:
1895 #ifndef PROFILE
1896 		if (pledge("stdio rpath recvfd unveil", NULL) == -1)
1897 			err(1, "pledge");
1898 #endif
1899 		apply_unveil_repo_readonly(repo_path);
1900 		repo_read_main(title, repo_path, pack_fds, temp_fds);
1901 		/* NOTREACHED */
1902 		exit(0);
1903 	case PROC_REPO_WRITE:
1904 #ifndef PROFILE
1905 		if (pledge("stdio rpath recvfd unveil", NULL) == -1)
1906 			err(1, "pledge");
1907 #endif
1908 		apply_unveil_repo_readonly(repo_path);
1909 		repo_write_main(title, repo_path, pack_fds, temp_fds);
1910 		/* NOTREACHED */
1911 		exit(0);
1912 	default:
1913 		fatal("invalid process id %d", proc_id);
1914 	}
1915 
1916 	if (proc_id != PROC_GOTD)
1917 		fatal("invalid process id %d", proc_id);
1918 
1919 	apply_unveil_selfexec();
1920 
1921 	signal_set(&evsigint, SIGINT, gotd_sighdlr, NULL);
1922 	signal_set(&evsigterm, SIGTERM, gotd_sighdlr, NULL);
1923 	signal_set(&evsighup, SIGHUP, gotd_sighdlr, NULL);
1924 	signal_set(&evsigusr1, SIGUSR1, gotd_sighdlr, NULL);
1925 	signal(SIGPIPE, SIG_IGN);
1926 
1927 	signal_add(&evsigint, NULL);
1928 	signal_add(&evsigterm, NULL);
1929 	signal_add(&evsighup, NULL);
1930 	signal_add(&evsigusr1, NULL);
1931 
1932 	gotd_imsg_event_add(&gotd.listen_proc.iev);
1933 
1934 	event_dispatch();
1935 
1936 	free(repo_path);
1937 	gotd_shutdown();
1938 
1939 	return 0;
1940 }