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Date:: Sun Feb 12 11:16:22 2023 UTC
Message:: rename lib/sha1.c to lib/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(void)
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 	if (proc) {
343 		event_del(&proc->iev.ev);
344 		msgbuf_clear(&proc->iev.ibuf.w);
345 		close(proc->iev.ibuf.fd);
346 		kill_proc(proc, 0);
347 		wait_for_child(proc->pid);
348 		free(proc);
349 		proc = NULL;
350 	}
351 
352 	idisconnect.client_id = client->id;
353 	if (gotd_imsg_compose_event(&listen_proc->iev,
354 	    GOTD_IMSG_DISCONNECT, PROC_GOTD, -1,
355 	    &idisconnect, sizeof(idisconnect)) == -1)
356 		log_warn("imsg compose DISCONNECT");
357 
358 	slot = client_hash(client->id) % nitems(gotd_clients);
359 	STAILQ_REMOVE(&gotd_clients[slot], client, gotd_client, entry);
360 	imsg_clear(&client->iev.ibuf);
361 	event_del(&client->iev.ev);
362 	evtimer_del(&client->tmo);
363 	if (client->fd != -1)
364 		close(client->fd);
365 	else if (client->iev.ibuf.fd != -1)
366 		close(client->iev.ibuf.fd);
367 	free(client);
368 	client_cnt--;
369 }
370 
371 static void
372 disconnect_on_error(struct gotd_client *client, const struct got_error *err)
373 {
374 	struct imsgbuf ibuf;
375 
376 	log_warnx("uid %d: %s", client->euid, err->msg);
377 	if (err->code != GOT_ERR_EOF && client->fd != -1) {
378 		imsg_init(&ibuf, client->fd);
379 		gotd_imsg_send_error(&ibuf, 0, PROC_GOTD, err);
380 		imsg_clear(&ibuf);
381 	}
382 	disconnect(client);
383 }
384 
385 static const struct got_error *
386 send_repo_info(struct gotd_imsgev *iev, struct gotd_repo *repo)
387 {
388 	const struct got_error *err = NULL;
389 	struct gotd_imsg_info_repo irepo;
390 
391 	memset(&irepo, 0, sizeof(irepo));
392 
393 	if (strlcpy(irepo.repo_name, repo->name, sizeof(irepo.repo_name))
394 	    >= sizeof(irepo.repo_name))
395 		return got_error_msg(GOT_ERR_NO_SPACE, "repo name too long");
396 	if (strlcpy(irepo.repo_path, repo->path, sizeof(irepo.repo_path))
397 	    >= sizeof(irepo.repo_path))
398 		return got_error_msg(GOT_ERR_NO_SPACE, "repo path too long");
399 
400 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_INFO_REPO, PROC_GOTD, -1,
401 	    &irepo, sizeof(irepo)) == -1) {
402 		err = got_error_from_errno("imsg compose INFO_REPO");
403 		if (err)
404 			return err;
405 	}
406 
407 	return NULL;
408 }
409 
410 static const struct got_error *
411 send_client_info(struct gotd_imsgev *iev, struct gotd_client *client)
412 {
413 	const struct got_error *err = NULL;
414 	struct gotd_imsg_info_client iclient;
415 	struct gotd_child_proc *proc;
416 
417 	memset(&iclient, 0, sizeof(iclient));
418 	iclient.euid = client->euid;
419 	iclient.egid = client->egid;
420 
421 	proc = client->repo;
422 	if (proc) {
423 		if (strlcpy(iclient.repo_name, proc->repo_path,
424 		    sizeof(iclient.repo_name)) >= sizeof(iclient.repo_name)) {
425 			return got_error_msg(GOT_ERR_NO_SPACE,
426 			    "repo name too long");
427 		}
428 		if (client_is_writing(client))
429 			iclient.is_writing = 1;
430 
431 		iclient.repo_child_pid = proc->pid;
432 	}
433 
434 	if (client->session)
435 		iclient.session_child_pid = client->session->pid;
436 
437 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_INFO_CLIENT, PROC_GOTD, -1,
438 	    &iclient, sizeof(iclient)) == -1) {
439 		err = got_error_from_errno("imsg compose INFO_CLIENT");
440 		if (err)
441 			return err;
442 	}
443 
444 	return NULL;
445 }
446 
447 static const struct got_error *
448 send_info(struct gotd_client *client)
449 {
450 	const struct got_error *err = NULL;
451 	struct gotd_imsg_info info;
452 	uint64_t slot;
453 	struct gotd_repo *repo;
454 
455 	if (client->euid != 0)
456 		return got_error_set_errno(EPERM, "info");
457 
458 	info.pid = gotd.pid;
459 	info.verbosity = gotd.verbosity;
460 	info.nrepos = gotd.nrepos;
461 	info.nclients = client_cnt - 1;
462 
463 	if (gotd_imsg_compose_event(&client->iev, GOTD_IMSG_INFO, PROC_GOTD, -1,
464 	    &info, sizeof(info)) == -1) {
465 		err = got_error_from_errno("imsg compose INFO");
466 		if (err)
467 			return err;
468 	}
469 
470 	TAILQ_FOREACH(repo, &gotd.repos, entry) {
471 		err = send_repo_info(&client->iev, repo);
472 		if (err)
473 			return err;
474 	}
475 
476 	for (slot = 0; slot < nitems(gotd_clients); slot++) {
477 		struct gotd_client *c;
478 		STAILQ_FOREACH(c, &gotd_clients[slot], entry) {
479 			if (c->id == client->id)
480 				continue;
481 			err = send_client_info(&client->iev, c);
482 			if (err)
483 				return err;
484 		}
485 	}
486 
487 	return NULL;
488 }
489 
490 static const struct got_error *
491 stop_gotd(struct gotd_client *client)
492 {
493 
494 	if (client->euid != 0)
495 		return got_error_set_errno(EPERM, "stop");
496 
497 	gotd_shutdown();
498 	/* NOTREACHED */
499 	return NULL;
500 }
501 
502 static struct gotd_repo *
503 find_repo_by_name(const char *repo_name)
504 {
505 	struct gotd_repo *repo;
506 	size_t namelen;
507 
508 	TAILQ_FOREACH(repo, &gotd.repos, entry) {
509 		namelen = strlen(repo->name);
510 		if (strncmp(repo->name, repo_name, namelen) != 0)
511 			continue;
512 		if (repo_name[namelen] == '\0' ||
513 		    strcmp(&repo_name[namelen], ".git") == 0)
514 			return repo;
515 	}
516 
517 	return NULL;
518 }
519 
520 static const struct got_error *
521 start_client_authentication(struct gotd_client *client, struct imsg *imsg)
522 {
523 	const struct got_error *err;
524 	struct gotd_imsg_list_refs ireq;
525 	struct gotd_repo *repo = NULL;
526 	size_t datalen;
527 
528 	log_debug("list-refs request from uid %d", client->euid);
529 
530 	if (client->state != GOTD_CLIENT_STATE_NEW)
531 		return got_error_msg(GOT_ERR_BAD_REQUEST,
532 		    "unexpected list-refs request received");
533 
534 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
535 	if (datalen != sizeof(ireq))
536 		return got_error(GOT_ERR_PRIVSEP_LEN);
537 
538 	memcpy(&ireq, imsg->data, datalen);
539 
540 	if (ireq.client_is_reading) {
541 		err = ensure_client_is_not_writing(client);
542 		if (err)
543 			return err;
544 		repo = find_repo_by_name(ireq.repo_name);
545 		if (repo == NULL)
546 			return got_error(GOT_ERR_NOT_GIT_REPO);
547 		err = start_auth_child(client, GOTD_AUTH_READ, repo,
548 		    gotd.argv0, gotd.confpath, gotd.daemonize,
549 		    gotd.verbosity);
550 		if (err)
551 			return err;
552 	} else {
553 		err = ensure_client_is_not_reading(client);
554 		if (err)
555 			return err;
556 		repo = find_repo_by_name(ireq.repo_name);
557 		if (repo == NULL)
558 			return got_error(GOT_ERR_NOT_GIT_REPO);
559 		err = start_auth_child(client,
560 		    GOTD_AUTH_READ | GOTD_AUTH_WRITE,
561 		    repo, gotd.argv0, gotd.confpath, gotd.daemonize,
562 		    gotd.verbosity);
563 		if (err)
564 			return err;
565 	}
566 
567 	evtimer_add(&client->tmo, &auth_timeout);
568 
569 	/* Flow continues upon authentication successs/failure or timeout. */
570 	return NULL;
571 }
572 
573 static void
574 gotd_request(int fd, short events, void *arg)
575 {
576 	struct gotd_imsgev *iev = arg;
577 	struct imsgbuf *ibuf = &iev->ibuf;
578 	struct gotd_client *client = iev->handler_arg;
579 	const struct got_error *err = NULL;
580 	struct imsg imsg;
581 	ssize_t n;
582 
583 	if (events & EV_WRITE) {
584 		while (ibuf->w.queued) {
585 			n = msgbuf_write(&ibuf->w);
586 			if (n == -1 && errno == EPIPE) {
587 				/*
588 				 * The client has closed its socket.
589 				 * This can happen when Git clients are
590 				 * done sending pack file data.
591 				 */
592 				msgbuf_clear(&ibuf->w);
593 				continue;
594 			} else if (n == -1 && errno != EAGAIN) {
595 				err = got_error_from_errno("imsg_flush");
596 				disconnect_on_error(client, err);
597 				return;
598 			}
599 			if (n == 0) {
600 				/* Connection closed. */
601 				err = got_error(GOT_ERR_EOF);
602 				disconnect_on_error(client, err);
603 				return;
604 			}
605 		}
606 
607 		/* Disconnect gotctl(8) now that messages have been sent. */
608 		if (!client_is_reading(client) && !client_is_writing(client)) {
609 			disconnect(client);
610 			return;
611 		}
612 	}
613 
614 	if ((events & EV_READ) == 0)
615 		return;
616 
617 	memset(&imsg, 0, sizeof(imsg));
618 
619 	while (err == NULL) {
620 		err = gotd_imsg_recv(&imsg, ibuf, 0);
621 		if (err) {
622 			if (err->code == GOT_ERR_PRIVSEP_READ)
623 				err = NULL;
624 			break;
625 		}
626 
627 		evtimer_del(&client->tmo);
628 
629 		switch (imsg.hdr.type) {
630 		case GOTD_IMSG_INFO:
631 			err = send_info(client);
632 			break;
633 		case GOTD_IMSG_STOP:
634 			err = stop_gotd(client);
635 			break;
636 		case GOTD_IMSG_LIST_REFS:
637 			err = start_client_authentication(client, &imsg);
638 			break;
639 		default:
640 			log_debug("unexpected imsg %d", imsg.hdr.type);
641 			err = got_error(GOT_ERR_PRIVSEP_MSG);
642 			break;
643 		}
644 
645 		imsg_free(&imsg);
646 	}
647 
648 	if (err) {
649 		disconnect_on_error(client, err);
650 	} else {
651 		gotd_imsg_event_add(&client->iev);
652 	}
653 }
654 
655 static void
656 gotd_auth_timeout(int fd, short events, void *arg)
657 {
658 	struct gotd_client *client = arg;
659 
660 	log_debug("disconnecting uid %d due to authentication timeout",
661 	    client->euid);
662 	disconnect(client);
663 }
664 
665 static const struct got_error *
666 recv_connect(uint32_t *client_id, struct imsg *imsg)
667 {
668 	const struct got_error *err = NULL;
669 	struct gotd_imsg_connect iconnect;
670 	size_t datalen;
671 	int s = -1;
672 	struct gotd_client *client = NULL;
673 
674 	*client_id = 0;
675 
676 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
677 	if (datalen != sizeof(iconnect))
678 		return got_error(GOT_ERR_PRIVSEP_LEN);
679 	memcpy(&iconnect, imsg->data, sizeof(iconnect));
680 
681 	s = imsg->fd;
682 	if (s == -1) {
683 		err = got_error(GOT_ERR_PRIVSEP_NO_FD);
684 		goto done;
685 	}
686 
687 	if (find_client(iconnect.client_id)) {
688 		err = got_error_msg(GOT_ERR_CLIENT_ID, "duplicate client ID");
689 		goto done;
690 	}
691 
692 	client = calloc(1, sizeof(*client));
693 	if (client == NULL) {
694 		err = got_error_from_errno("calloc");
695 		goto done;
696 	}
697 
698 	*client_id = iconnect.client_id;
699 
700 	client->state = GOTD_CLIENT_STATE_NEW;
701 	client->id = iconnect.client_id;
702 	client->fd = s;
703 	s = -1;
704 	/* The auth process will verify UID/GID for us. */
705 	client->euid = iconnect.euid;
706 	client->egid = iconnect.egid;
707 
708 	imsg_init(&client->iev.ibuf, client->fd);
709 	client->iev.handler = gotd_request;
710 	client->iev.events = EV_READ;
711 	client->iev.handler_arg = client;
712 
713 	event_set(&client->iev.ev, client->fd, EV_READ, gotd_request,
714 	    &client->iev);
715 	gotd_imsg_event_add(&client->iev);
716 
717 	evtimer_set(&client->tmo, gotd_auth_timeout, client);
718 
719 	add_client(client);
720 	log_debug("%s: new client uid %d connected on fd %d", __func__,
721 	    client->euid, client->fd);
722 done:
723 	if (err) {
724 		struct gotd_child_proc *listen_proc = &gotd.listen_proc;
725 		struct gotd_imsg_disconnect idisconnect;
726 
727 		idisconnect.client_id = client->id;
728 		if (gotd_imsg_compose_event(&listen_proc->iev,
729 		    GOTD_IMSG_DISCONNECT, PROC_GOTD, -1,
730 		    &idisconnect, sizeof(idisconnect)) == -1)
731 			log_warn("imsg compose DISCONNECT");
732 
733 		if (s != -1)
734 			close(s);
735 	}
736 
737 	return err;
738 }
739 
740 static const char *gotd_proc_names[PROC_MAX] = {
741 	"parent",
742 	"listen",
743 	"auth",
744 	"session",
745 	"repo_read",
746 	"repo_write"
747 };
748 
749 static void
750 kill_proc(struct gotd_child_proc *proc, int fatal)
751 {
752 	if (fatal) {
753 		log_warnx("sending SIGKILL to PID %d", proc->pid);
754 		kill(proc->pid, SIGKILL);
755 	} else
756 		kill(proc->pid, SIGTERM);
757 }
758 
759 static void
760 gotd_shutdown(void)
761 {
762 	struct gotd_child_proc *proc;
763 	uint64_t slot;
764 
765 	log_debug("shutting down");
766 	for (slot = 0; slot < nitems(gotd_clients); slot++) {
767 		struct gotd_client *c, *tmp;
768 
769 		STAILQ_FOREACH_SAFE(c, &gotd_clients[slot], entry, tmp)
770 			disconnect(c);
771 	}
772 
773 	proc = &gotd.listen_proc;
774 	msgbuf_clear(&proc->iev.ibuf.w);
775 	close(proc->iev.ibuf.fd);
776 	kill_proc(proc, 0);
777 	wait_for_child(proc->pid);
778 
779 	log_info("terminating");
780 	exit(0);
781 }
782 
783 void
784 gotd_sighdlr(int sig, short event, void *arg)
785 {
786 	/*
787 	 * Normal signal handler rules don't apply because libevent
788 	 * decouples for us.
789 	 */
790 
791 	switch (sig) {
792 	case SIGHUP:
793 		log_info("%s: ignoring SIGHUP", __func__);
794 		break;
795 	case SIGUSR1:
796 		log_info("%s: ignoring SIGUSR1", __func__);
797 		break;
798 	case SIGTERM:
799 	case SIGINT:
800 		gotd_shutdown();
801 		break;
802 	default:
803 		fatalx("unexpected signal");
804 	}
805 }
806 
807 static const struct got_error *
808 ensure_proc_is_reading(struct gotd_client *client,
809     struct gotd_child_proc *proc)
810 {
811 	if (!client_is_reading(client)) {
812 		kill_proc(proc, 1);
813 		return got_error_fmt(GOT_ERR_BAD_PACKET,
814 		    "PID %d handled a read-request for uid %d but this "
815 		    "user is not reading from a repository", proc->pid,
816 		    client->euid);
817 	}
818 
819 	return NULL;
820 }
821 
822 static const struct got_error *
823 ensure_proc_is_writing(struct gotd_client *client,
824     struct gotd_child_proc *proc)
825 {
826 	if (!client_is_writing(client)) {
827 		kill_proc(proc, 1);
828 		return got_error_fmt(GOT_ERR_BAD_PACKET,
829 		    "PID %d handled a write-request for uid %d but this "
830 		    "user is not writing to a repository", proc->pid,
831 		    client->euid);
832 	}
833 
834 	return NULL;
835 }
836 
837 static int
838 verify_imsg_src(struct gotd_client *client, struct gotd_child_proc *proc,
839     struct imsg *imsg)
840 {
841 	const struct got_error *err;
842 	int ret = 0;
843 
844 	if (proc->type == PROC_REPO_READ || proc->type == PROC_REPO_WRITE) {
845 		if (client->repo == NULL)
846 			fatalx("no process found for uid %d", client->euid);
847 		if (proc->pid != client->repo->pid) {
848 			kill_proc(proc, 1);
849 			log_warnx("received message from PID %d for uid %d, "
850 			    "while PID %d is the process serving this user",
851 			    proc->pid, client->euid, client->repo->pid);
852 			return 0;
853 		}
854 	}
855 	if (proc->type == PROC_SESSION) {
856 		if (client->session == NULL) {
857 			log_warnx("no session found for uid %d", client->euid);
858 			return 0;
859 		}
860 		if (proc->pid != client->session->pid) {
861 			kill_proc(proc, 1);
862 			log_warnx("received message from PID %d for uid %d, "
863 			    "while PID %d is the process serving this user",
864 			    proc->pid, client->euid, client->session->pid);
865 			return 0;
866 		}
867 	}
868 
869 	switch (imsg->hdr.type) {
870 	case GOTD_IMSG_ERROR:
871 		ret = 1;
872 		break;
873 	case GOTD_IMSG_CONNECT:
874 		if (proc->type != PROC_LISTEN) {
875 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
876 			    "new connection for uid %d from PID %d "
877 			    "which is not the listen process",
878 			    proc->pid, client->euid);
879 		} else
880 			ret = 1;
881 		break;
882 	case GOTD_IMSG_ACCESS_GRANTED:
883 		if (proc->type != PROC_AUTH) {
884 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
885 			    "authentication of uid %d from PID %d "
886 			    "which is not the auth process",
887 			    proc->pid, client->euid);
888 		} else
889 			ret = 1;
890 		break;
891 	case GOTD_IMSG_CLIENT_SESSION_READY:
892 		if (proc->type != PROC_SESSION) {
893 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
894 			    "unexpected \"ready\" signal from PID %d",
895 			    proc->pid);
896 		} else
897 			ret = 1;
898 		break;
899 	case GOTD_IMSG_REPO_CHILD_READY:
900 		if (proc->type != PROC_REPO_READ &&
901 		    proc->type != PROC_REPO_WRITE) {
902 			err = got_error_fmt(GOT_ERR_BAD_PACKET,
903 			    "unexpected \"ready\" signal from PID %d",
904 			    proc->pid);
905 		} else
906 			ret = 1;
907 		break;
908 	case GOTD_IMSG_PACKFILE_DONE:
909 		err = ensure_proc_is_reading(client, proc);
910 		if (err)
911 			log_warnx("uid %d: %s", client->euid, err->msg);
912 		else
913 			ret = 1;
914 		break;
915 	case GOTD_IMSG_PACKFILE_INSTALL:
916 	case GOTD_IMSG_REF_UPDATES_START:
917 	case GOTD_IMSG_REF_UPDATE:
918 		err = ensure_proc_is_writing(client, proc);
919 		if (err)
920 			log_warnx("uid %d: %s", client->euid, err->msg);
921 		else
922 			ret = 1;
923 		break;
924 	default:
925 		log_debug("%s: unexpected imsg %d", __func__, imsg->hdr.type);
926 		break;
927 	}
928 
929 	return ret;
930 }
931 
932 static const struct got_error *
933 connect_repo_child(struct gotd_client *client,
934     struct gotd_child_proc *repo_proc)
935 {
936 	static const struct got_error *err;
937 	struct gotd_imsgev *session_iev = &client->session->iev;
938 	struct gotd_imsg_connect_repo_child ireq;
939 	int pipe[2];
940 
941 	if (client->state != GOTD_CLIENT_STATE_ACCESS_GRANTED)
942 		return got_error_msg(GOT_ERR_BAD_REQUEST,
943 		    "unexpected repo child ready signal received");
944 
945 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
946 	    PF_UNSPEC, pipe) == -1)
947 		fatal("socketpair");
948 
949 	memset(&ireq, 0, sizeof(ireq));
950 	ireq.client_id = client->id;
951 	ireq.proc_id = repo_proc->type;
952 
953 	/* Pass repo child pipe to session child process. */
954 	if (gotd_imsg_compose_event(session_iev, GOTD_IMSG_CONNECT_REPO_CHILD,
955 	    PROC_GOTD, pipe[0], &ireq, sizeof(ireq)) == -1) {
956 		err = got_error_from_errno("imsg compose CONNECT_REPO_CHILD");
957 		close(pipe[0]);
958 		close(pipe[1]);
959 		return err;
960 	}
961 
962 	/* Pass session child pipe to repo child process. */
963 	if (gotd_imsg_compose_event(&repo_proc->iev,
964 	    GOTD_IMSG_CONNECT_REPO_CHILD, PROC_GOTD, pipe[1], NULL, 0) == -1) {
965 		err = got_error_from_errno("imsg compose CONNECT_REPO_CHILD");
966 		close(pipe[1]);
967 		return err;
968 	}
969 
970 	return NULL;
971 }
972 
973 static void
974 gotd_dispatch_listener(int fd, short event, void *arg)
975 {
976 	struct gotd_imsgev *iev = arg;
977 	struct imsgbuf *ibuf = &iev->ibuf;
978 	struct gotd_child_proc *proc = &gotd.listen_proc;
979 	ssize_t n;
980 	int shut = 0;
981 	struct imsg imsg;
982 
983 	if (proc->iev.ibuf.fd != fd)
984 		fatalx("%s: unexpected fd %d", __func__, fd);
985 
986 	if (event & EV_READ) {
987 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
988 			fatal("imsg_read error");
989 		if (n == 0) {
990 			/* Connection closed. */
991 			shut = 1;
992 			goto done;
993 		}
994 	}
995 
996 	if (event & EV_WRITE) {
997 		n = msgbuf_write(&ibuf->w);
998 		if (n == -1 && errno != EAGAIN)
999 			fatal("msgbuf_write");
1000 		if (n == 0) {
1001 			/* Connection closed. */
1002 			shut = 1;
1003 			goto done;
1004 		}
1005 	}
1006 
1007 	for (;;) {
1008 		const struct got_error *err = NULL;
1009 		struct gotd_client *client = NULL;
1010 		uint32_t client_id = 0;
1011 		int do_disconnect = 0;
1012 
1013 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1014 			fatal("%s: imsg_get error", __func__);
1015 		if (n == 0)	/* No more messages. */
1016 			break;
1017 
1018 		switch (imsg.hdr.type) {
1019 		case GOTD_IMSG_ERROR:
1020 			do_disconnect = 1;
1021 			err = gotd_imsg_recv_error(&client_id, &imsg);
1022 			break;
1023 		case GOTD_IMSG_CONNECT:
1024 			err = recv_connect(&client_id, &imsg);
1025 			break;
1026 		default:
1027 			log_debug("unexpected imsg %d", imsg.hdr.type);
1028 			break;
1029 		}
1030 
1031 		client = find_client(client_id);
1032 		if (client == NULL) {
1033 			log_warnx("%s: client not found", __func__);
1034 			imsg_free(&imsg);
1035 			continue;
1036 		}
1037 
1038 		if (err)
1039 			log_warnx("uid %d: %s", client->euid, err->msg);
1040 
1041 		if (do_disconnect) {
1042 			if (err)
1043 				disconnect_on_error(client, err);
1044 			else
1045 				disconnect(client);
1046 		}
1047 
1048 		imsg_free(&imsg);
1049 	}
1050 done:
1051 	if (!shut) {
1052 		gotd_imsg_event_add(iev);
1053 	} else {
1054 		/* This pipe is dead. Remove its event handler */
1055 		event_del(&iev->ev);
1056 		event_loopexit(NULL);
1057 	}
1058 }
1059 
1060 static void
1061 gotd_dispatch_auth_child(int fd, short event, void *arg)
1062 {
1063 	const struct got_error *err = NULL;
1064 	struct gotd_imsgev *iev = arg;
1065 	struct imsgbuf *ibuf = &iev->ibuf;
1066 	struct gotd_client *client;
1067 	struct gotd_repo *repo = NULL;
1068 	ssize_t n;
1069 	int shut = 0;
1070 	struct imsg imsg;
1071 	uint32_t client_id = 0;
1072 	int do_disconnect = 0;
1073 
1074 	client = find_client_by_proc_fd(fd);
1075 	if (client == NULL) {
1076 		/* Can happen during process teardown. */
1077 		warnx("cannot find client for fd %d", fd);
1078 		shut = 1;
1079 		goto done;
1080 	}
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 		/* Can happen during process teardown. */
1224 		warnx("cannot find client for fd %d", fd);
1225 		shut = 1;
1226 		goto done;
1227 	}
1228 
1229 	if (event & EV_READ) {
1230 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1231 			fatal("imsg_read error");
1232 		if (n == 0) {
1233 			/* Connection closed. */
1234 			shut = 1;
1235 			goto done;
1236 		}
1237 	}
1238 
1239 	if (event & EV_WRITE) {
1240 		n = msgbuf_write(&ibuf->w);
1241 		if (n == -1 && errno != EAGAIN)
1242 			fatal("msgbuf_write");
1243 		if (n == 0) {
1244 			/* Connection closed. */
1245 			shut = 1;
1246 			goto done;
1247 		}
1248 	}
1249 
1250 	proc = client->session;
1251 	if (proc == NULL)
1252 		fatalx("cannot find session child process for fd %d", fd);
1253 
1254 	for (;;) {
1255 		const struct got_error *err = NULL;
1256 		uint32_t client_id = 0;
1257 		int do_disconnect = 0, do_start_repo_child = 0;
1258 
1259 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1260 			fatal("%s: imsg_get error", __func__);
1261 		if (n == 0)	/* No more messages. */
1262 			break;
1263 
1264 		switch (imsg.hdr.type) {
1265 		case GOTD_IMSG_ERROR:
1266 			do_disconnect = 1;
1267 			err = gotd_imsg_recv_error(&client_id, &imsg);
1268 			break;
1269 		case GOTD_IMSG_CLIENT_SESSION_READY:
1270 			if (client->state != GOTD_CLIENT_STATE_ACCESS_GRANTED) {
1271 				err = got_error(GOT_ERR_PRIVSEP_MSG);
1272 				break;
1273 			}
1274 			do_start_repo_child = 1;
1275 			break;
1276 		case GOTD_IMSG_DISCONNECT:
1277 			do_disconnect = 1;
1278 			break;
1279 		default:
1280 			log_debug("unexpected imsg %d", imsg.hdr.type);
1281 			break;
1282 		}
1283 
1284 		if (!verify_imsg_src(client, proc, &imsg)) {
1285 			log_debug("dropping imsg type %d from PID %d",
1286 			    imsg.hdr.type, proc->pid);
1287 			imsg_free(&imsg);
1288 			continue;
1289 		}
1290 		if (err)
1291 			log_warnx("uid %d: %s", client->euid, err->msg);
1292 
1293 		if (do_start_repo_child) {
1294 			struct gotd_repo *repo;
1295 
1296 			repo = find_repo_by_name(client->session->repo_name);
1297 			if (repo != NULL) {
1298 				enum gotd_procid proc_type;
1299 
1300 				if (client->required_auth & GOTD_AUTH_WRITE)
1301 					proc_type = PROC_REPO_WRITE;
1302 				else
1303 					proc_type = PROC_REPO_READ;
1304 
1305 				err = start_repo_child(client, proc_type, repo,
1306 				    gotd.argv0, gotd.confpath, gotd.daemonize,
1307 				    gotd.verbosity);
1308 			} else
1309 				err = got_error(GOT_ERR_NOT_GIT_REPO);
1310 
1311 			if (err) {
1312 				log_warnx("uid %d: %s", client->euid, err->msg);
1313 				do_disconnect = 1;
1314 			}
1315 		}
1316 
1317 		if (do_disconnect) {
1318 			if (err)
1319 				disconnect_on_error(client, err);
1320 			else
1321 				disconnect(client);
1322 		}
1323 
1324 		imsg_free(&imsg);
1325 	}
1326 done:
1327 	if (!shut) {
1328 		gotd_imsg_event_add(iev);
1329 	} else {
1330 		/* This pipe is dead. Remove its event handler */
1331 		event_del(&iev->ev);
1332 		disconnect(client);
1333 	}
1334 }
1335 
1336 static void
1337 gotd_dispatch_repo_child(int fd, short event, void *arg)
1338 {
1339 	struct gotd_imsgev *iev = arg;
1340 	struct imsgbuf *ibuf = &iev->ibuf;
1341 	struct gotd_child_proc *proc = NULL;
1342 	struct gotd_client *client;
1343 	ssize_t n;
1344 	int shut = 0;
1345 	struct imsg imsg;
1346 
1347 	client = find_client_by_proc_fd(fd);
1348 	if (client == NULL) {
1349 		/* Can happen during process teardown. */
1350 		warnx("cannot find client for fd %d", fd);
1351 		shut = 1;
1352 		goto done;
1353 	}
1354 
1355 	if (event & EV_READ) {
1356 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
1357 			fatal("imsg_read error");
1358 		if (n == 0) {
1359 			/* Connection closed. */
1360 			shut = 1;
1361 			goto done;
1362 		}
1363 	}
1364 
1365 	if (event & EV_WRITE) {
1366 		n = msgbuf_write(&ibuf->w);
1367 		if (n == -1 && errno != EAGAIN)
1368 			fatal("msgbuf_write");
1369 		if (n == 0) {
1370 			/* Connection closed. */
1371 			shut = 1;
1372 			goto done;
1373 		}
1374 	}
1375 
1376 	proc = client->repo;
1377 	if (proc == NULL)
1378 		fatalx("cannot find child process for fd %d", fd);
1379 
1380 	for (;;) {
1381 		const struct got_error *err = NULL;
1382 		uint32_t client_id = 0;
1383 		int do_disconnect = 0;
1384 
1385 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1386 			fatal("%s: imsg_get error", __func__);
1387 		if (n == 0)	/* No more messages. */
1388 			break;
1389 
1390 		switch (imsg.hdr.type) {
1391 		case GOTD_IMSG_ERROR:
1392 			do_disconnect = 1;
1393 			err = gotd_imsg_recv_error(&client_id, &imsg);
1394 			break;
1395 		case GOTD_IMSG_REPO_CHILD_READY:
1396 			err = connect_session(client);
1397 			if (err)
1398 				break;
1399 			err = connect_repo_child(client, proc);
1400 			break;
1401 		default:
1402 			log_debug("unexpected imsg %d", imsg.hdr.type);
1403 			break;
1404 		}
1405 
1406 		if (!verify_imsg_src(client, proc, &imsg)) {
1407 			log_debug("dropping imsg type %d from PID %d",
1408 			    imsg.hdr.type, proc->pid);
1409 			imsg_free(&imsg);
1410 			continue;
1411 		}
1412 		if (err)
1413 			log_warnx("uid %d: %s", client->euid, err->msg);
1414 
1415 		if (do_disconnect) {
1416 			if (err)
1417 				disconnect_on_error(client, err);
1418 			else
1419 				disconnect(client);
1420 		}
1421 
1422 		imsg_free(&imsg);
1423 	}
1424 done:
1425 	if (!shut) {
1426 		gotd_imsg_event_add(iev);
1427 	} else {
1428 		/* This pipe is dead. Remove its event handler */
1429 		event_del(&iev->ev);
1430 		disconnect(client);
1431 	}
1432 }
1433 
1434 static pid_t
1435 start_child(enum gotd_procid proc_id, const char *repo_path,
1436     char *argv0, const char *confpath, int fd, int daemonize, int verbosity)
1437 {
1438 	char	*argv[11];
1439 	int	 argc = 0;
1440 	pid_t	 pid;
1441 
1442 	switch (pid = fork()) {
1443 	case -1:
1444 		fatal("cannot fork");
1445 	case 0:
1446 		break;
1447 	default:
1448 		close(fd);
1449 		return pid;
1450 	}
1451 
1452 	if (fd != GOTD_FILENO_MSG_PIPE) {
1453 		if (dup2(fd, GOTD_FILENO_MSG_PIPE) == -1)
1454 			fatal("cannot setup imsg fd");
1455 	} else if (fcntl(fd, F_SETFD, 0) == -1)
1456 		fatal("cannot setup imsg fd");
1457 
1458 	argv[argc++] = argv0;
1459 	switch (proc_id) {
1460 	case PROC_LISTEN:
1461 		argv[argc++] = (char *)"-L";
1462 		break;
1463 	case PROC_AUTH:
1464 		argv[argc++] = (char *)"-A";
1465 		break;
1466 	case PROC_SESSION:
1467 		argv[argc++] = (char *)"-S";
1468 		break;
1469 	case PROC_REPO_READ:
1470 		argv[argc++] = (char *)"-R";
1471 		break;
1472 	case PROC_REPO_WRITE:
1473 		argv[argc++] = (char *)"-W";
1474 		break;
1475 	default:
1476 		fatalx("invalid process id %d", proc_id);
1477 	}
1478 
1479 	argv[argc++] = (char *)"-f";
1480 	argv[argc++] = (char *)confpath;
1481 
1482 	if (repo_path) {
1483 		argv[argc++] = (char *)"-P";
1484 		argv[argc++] = (char *)repo_path;
1485 	}
1486 
1487 	if (!daemonize)
1488 		argv[argc++] = (char *)"-d";
1489 	if (verbosity > 0)
1490 		argv[argc++] = (char *)"-v";
1491 	if (verbosity > 1)
1492 		argv[argc++] = (char *)"-v";
1493 	argv[argc++] = NULL;
1494 
1495 	execvp(argv0, argv);
1496 	fatal("execvp");
1497 }
1498 
1499 static void
1500 start_listener(char *argv0, const char *confpath, int daemonize, int verbosity)
1501 {
1502 	struct gotd_child_proc *proc = &gotd.listen_proc;
1503 
1504 	proc->type = PROC_LISTEN;
1505 
1506 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1507 	    PF_UNSPEC, proc->pipe) == -1)
1508 		fatal("socketpair");
1509 
1510 	proc->pid = start_child(proc->type, NULL, argv0, confpath,
1511 	    proc->pipe[1], daemonize, verbosity);
1512 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1513 	proc->iev.handler = gotd_dispatch_listener;
1514 	proc->iev.events = EV_READ;
1515 	proc->iev.handler_arg = NULL;
1516 }
1517 
1518 static const struct got_error *
1519 start_session_child(struct gotd_client *client, struct gotd_repo *repo,
1520     char *argv0, const char *confpath, int daemonize, int verbosity)
1521 {
1522 	struct gotd_child_proc *proc;
1523 
1524 	proc = calloc(1, sizeof(*proc));
1525 	if (proc == NULL)
1526 		return got_error_from_errno("calloc");
1527 
1528 	proc->type = PROC_SESSION;
1529 	if (strlcpy(proc->repo_name, repo->name,
1530 	    sizeof(proc->repo_name)) >= sizeof(proc->repo_name))
1531 		fatalx("repository name too long: %s", repo->name);
1532 	log_debug("starting client uid %d session for repository %s",
1533 	    client->euid, repo->name);
1534 	if (strlcpy(proc->repo_path, repo->path, sizeof(proc->repo_path)) >=
1535 	    sizeof(proc->repo_path))
1536 		fatalx("repository path too long: %s", repo->path);
1537 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1538 	    PF_UNSPEC, proc->pipe) == -1)
1539 		fatal("socketpair");
1540 	proc->pid = start_child(proc->type, proc->repo_path, argv0,
1541 	    confpath, proc->pipe[1], daemonize, verbosity);
1542 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1543 	log_debug("proc %s %s is on fd %d",
1544 	    gotd_proc_names[proc->type], proc->repo_path,
1545 	    proc->pipe[0]);
1546 	proc->iev.handler = gotd_dispatch_client_session;
1547 	proc->iev.events = EV_READ;
1548 	proc->iev.handler_arg = NULL;
1549 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1550 	    gotd_dispatch_client_session, &proc->iev);
1551 	gotd_imsg_event_add(&proc->iev);
1552 
1553 	client->session = proc;
1554 	return NULL;
1555 }
1556 
1557 static const struct got_error *
1558 start_repo_child(struct gotd_client *client, enum gotd_procid proc_type,
1559     struct gotd_repo *repo, char *argv0, const char *confpath,
1560     int daemonize, int verbosity)
1561 {
1562 	struct gotd_child_proc *proc;
1563 
1564 	if (proc_type != PROC_REPO_READ && proc_type != PROC_REPO_WRITE)
1565 		return got_error_msg(GOT_ERR_NOT_IMPL, "bad process type");
1566 
1567 	proc = calloc(1, sizeof(*proc));
1568 	if (proc == NULL)
1569 		return got_error_from_errno("calloc");
1570 
1571 	proc->type = proc_type;
1572 	if (strlcpy(proc->repo_name, repo->name,
1573 	    sizeof(proc->repo_name)) >= sizeof(proc->repo_name))
1574 		fatalx("repository name too long: %s", repo->name);
1575 	log_debug("starting %s for repository %s",
1576 	    proc->type == PROC_REPO_READ ? "reader" : "writer", repo->name);
1577 	if (strlcpy(proc->repo_path, repo->path, sizeof(proc->repo_path)) >=
1578 	    sizeof(proc->repo_path))
1579 		fatalx("repository path too long: %s", repo->path);
1580 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1581 	    PF_UNSPEC, proc->pipe) == -1)
1582 		fatal("socketpair");
1583 	proc->pid = start_child(proc->type, proc->repo_path, argv0,
1584 	    confpath, proc->pipe[1], daemonize, verbosity);
1585 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1586 	log_debug("proc %s %s is on fd %d",
1587 	    gotd_proc_names[proc->type], proc->repo_path,
1588 	    proc->pipe[0]);
1589 	proc->iev.handler = gotd_dispatch_repo_child;
1590 	proc->iev.events = EV_READ;
1591 	proc->iev.handler_arg = NULL;
1592 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1593 	    gotd_dispatch_repo_child, &proc->iev);
1594 	gotd_imsg_event_add(&proc->iev);
1595 
1596 	client->repo = proc;
1597 	return NULL;
1598 }
1599 
1600 static const struct got_error *
1601 start_auth_child(struct gotd_client *client, int required_auth,
1602     struct gotd_repo *repo, char *argv0, const char *confpath,
1603     int daemonize, int verbosity)
1604 {
1605 	const struct got_error *err = NULL;
1606 	struct gotd_child_proc *proc;
1607 	struct gotd_imsg_auth iauth;
1608 	int fd;
1609 
1610 	memset(&iauth, 0, sizeof(iauth));
1611 
1612 	fd = dup(client->fd);
1613 	if (fd == -1)
1614 		return got_error_from_errno("dup");
1615 
1616 	proc = calloc(1, sizeof(*proc));
1617 	if (proc == NULL) {
1618 		err = got_error_from_errno("calloc");
1619 		close(fd);
1620 		return err;
1621 	}
1622 
1623 	proc->type = PROC_AUTH;
1624 	if (strlcpy(proc->repo_name, repo->name,
1625 	    sizeof(proc->repo_name)) >= sizeof(proc->repo_name))
1626 		fatalx("repository name too long: %s", repo->name);
1627 	log_debug("starting auth for uid %d repository %s",
1628 	    client->euid, repo->name);
1629 	if (strlcpy(proc->repo_path, repo->path, sizeof(proc->repo_path)) >=
1630 	    sizeof(proc->repo_path))
1631 		fatalx("repository path too long: %s", repo->path);
1632 	if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK,
1633 	    PF_UNSPEC, proc->pipe) == -1)
1634 		fatal("socketpair");
1635 	proc->pid = start_child(proc->type, proc->repo_path, argv0,
1636 	    confpath, proc->pipe[1], daemonize, verbosity);
1637 	imsg_init(&proc->iev.ibuf, proc->pipe[0]);
1638 	log_debug("proc %s %s is on fd %d",
1639 	    gotd_proc_names[proc->type], proc->repo_path,
1640 	    proc->pipe[0]);
1641 	proc->iev.handler = gotd_dispatch_auth_child;
1642 	proc->iev.events = EV_READ;
1643 	proc->iev.handler_arg = NULL;
1644 	event_set(&proc->iev.ev, proc->iev.ibuf.fd, EV_READ,
1645 	    gotd_dispatch_auth_child, &proc->iev);
1646 	gotd_imsg_event_add(&proc->iev);
1647 
1648 	iauth.euid = client->euid;
1649 	iauth.egid = client->egid;
1650 	iauth.required_auth = required_auth;
1651 	iauth.client_id = client->id;
1652 	if (gotd_imsg_compose_event(&proc->iev, GOTD_IMSG_AUTHENTICATE,
1653 	    PROC_GOTD, fd, &iauth, sizeof(iauth)) == -1) {
1654 		log_warn("imsg compose AUTHENTICATE");
1655 		close(fd);
1656 		/* Let the auth_timeout handler tidy up. */
1657 	}
1658 
1659 	client->auth = proc;
1660 	client->required_auth = required_auth;
1661 	return NULL;
1662 }
1663 
1664 static void
1665 apply_unveil_repo_readonly(const char *repo_path)
1666 {
1667 	if (unveil(repo_path, "r") == -1)
1668 		fatal("unveil %s", repo_path);
1669 
1670 	if (unveil(NULL, NULL) == -1)
1671 		fatal("unveil");
1672 }
1673 
1674 static void
1675 apply_unveil_repo_readwrite(const char *repo_path)
1676 {
1677 	if (unveil(repo_path, "rwc") == -1)
1678 		fatal("unveil %s", repo_path);
1679 
1680 	if (unveil(GOT_TMPDIR_STR, "rwc") == -1)
1681 		fatal("unveil %s", GOT_TMPDIR_STR);
1682 
1683 	if (unveil(NULL, NULL) == -1)
1684 		fatal("unveil");
1685 }
1686 
1687 static void
1688 apply_unveil_none(void)
1689 {
1690 	if (unveil("/", "") == -1)
1691 		fatal("unveil");
1692 
1693 	if (unveil(NULL, NULL) == -1)
1694 		fatal("unveil");
1695 }
1696 
1697 static void
1698 apply_unveil_selfexec(void)
1699 {
1700 	if (unveil(gotd.argv0, "x") == -1)
1701 		fatal("unveil %s", gotd.argv0);
1702 
1703 	if (unveil(NULL, NULL) == -1)
1704 		fatal("unveil");
1705 }
1706 
1707 int
1708 main(int argc, char **argv)
1709 {
1710 	const struct got_error *error = NULL;
1711 	int ch, fd = -1, daemonize = 1, verbosity = 0, noaction = 0;
1712 	const char *confpath = GOTD_CONF_PATH;
1713 	char *argv0 = argv[0];
1714 	char title[2048];
1715 	struct passwd *pw = NULL;
1716 	char *repo_path = NULL;
1717 	enum gotd_procid proc_id = PROC_GOTD;
1718 	struct event evsigint, evsigterm, evsighup, evsigusr1;
1719 	int *pack_fds = NULL, *temp_fds = NULL;
1720 
1721 	log_init(1, LOG_DAEMON); /* Log to stderr until daemonized. */
1722 
1723 	while ((ch = getopt(argc, argv, "Adf:LnP:RSvW")) != -1) {
1724 		switch (ch) {
1725 		case 'A':
1726 			proc_id = PROC_AUTH;
1727 			break;
1728 		case 'd':
1729 			daemonize = 0;
1730 			break;
1731 		case 'f':
1732 			confpath = optarg;
1733 			break;
1734 		case 'L':
1735 			proc_id = PROC_LISTEN;
1736 			break;
1737 		case 'n':
1738 			noaction = 1;
1739 			break;
1740 		case 'P':
1741 			repo_path = realpath(optarg, NULL);
1742 			if (repo_path == NULL)
1743 				fatal("realpath '%s'", optarg);
1744 			break;
1745 		case 'R':
1746 			proc_id = PROC_REPO_READ;
1747 			break;
1748 		case 'S':
1749 			proc_id = PROC_SESSION;
1750 			break;
1751 		case 'v':
1752 			if (verbosity < 3)
1753 				verbosity++;
1754 			break;
1755 		case 'W':
1756 			proc_id = PROC_REPO_WRITE;
1757 			break;
1758 		default:
1759 			usage();
1760 		}
1761 	}
1762 
1763 	argc -= optind;
1764 	argv += optind;
1765 
1766 	if (argc != 0)
1767 		usage();
1768 
1769 	if (geteuid() && (proc_id == PROC_GOTD || proc_id == PROC_LISTEN))
1770 		fatalx("need root privileges");
1771 
1772 	if (parse_config(confpath, proc_id, &gotd) != 0)
1773 		return 1;
1774 
1775 	pw = getpwnam(gotd.user_name);
1776 	if (pw == NULL)
1777 		fatalx("user %s not found", gotd.user_name);
1778 
1779 	if (pw->pw_uid == 0)
1780 		fatalx("cannot run %s as the superuser", getprogname());
1781 
1782 	if (noaction) {
1783 		fprintf(stderr, "configuration OK\n");
1784 		return 0;
1785 	}
1786 
1787 	gotd.argv0 = argv0;
1788 	gotd.daemonize = daemonize;
1789 	gotd.verbosity = verbosity;
1790 	gotd.confpath = confpath;
1791 
1792 	/* Require an absolute path in argv[0] for reliable re-exec. */
1793 	if (!got_path_is_absolute(argv0))
1794 		fatalx("bad path \"%s\": must be an absolute path", argv0);
1795 
1796 	log_init(daemonize ? 0 : 1, LOG_DAEMON);
1797 	log_setverbose(verbosity);
1798 
1799 	if (proc_id == PROC_GOTD) {
1800 		snprintf(title, sizeof(title), "%s", gotd_proc_names[proc_id]);
1801 		arc4random_buf(&clients_hash_key, sizeof(clients_hash_key));
1802 		if (daemonize && daemon(1, 0) == -1)
1803 			fatal("daemon");
1804 		gotd.pid = getpid();
1805 		start_listener(argv0, confpath, daemonize, verbosity);
1806 	} else if (proc_id == PROC_LISTEN) {
1807 		snprintf(title, sizeof(title), "%s", gotd_proc_names[proc_id]);
1808 		if (verbosity) {
1809 			log_info("socket: %s", gotd.unix_socket_path);
1810 			log_info("user: %s", pw->pw_name);
1811 		}
1812 
1813 		fd = unix_socket_listen(gotd.unix_socket_path, pw->pw_uid,
1814 		    pw->pw_gid);
1815 		if (fd == -1) {
1816 			fatal("cannot listen on unix socket %s",
1817 			    gotd.unix_socket_path);
1818 		}
1819 	} else if (proc_id == PROC_AUTH) {
1820 		snprintf(title, sizeof(title), "%s %s",
1821 		    gotd_proc_names[proc_id], repo_path);
1822 	} else if (proc_id == PROC_REPO_READ || proc_id == PROC_REPO_WRITE ||
1823 	    proc_id == PROC_SESSION) {
1824 		error = got_repo_pack_fds_open(&pack_fds);
1825 		if (error != NULL)
1826 			fatalx("cannot open pack tempfiles: %s", error->msg);
1827 		error = got_repo_temp_fds_open(&temp_fds);
1828 		if (error != NULL)
1829 			fatalx("cannot open pack tempfiles: %s", error->msg);
1830 		if (repo_path == NULL)
1831 			fatalx("repository path not specified");
1832 		snprintf(title, sizeof(title), "%s %s",
1833 		    gotd_proc_names[proc_id], repo_path);
1834 	} else
1835 		fatal("invalid process id %d", proc_id);
1836 
1837 	setproctitle("%s", title);
1838 	log_procinit(title);
1839 
1840 	/* Drop root privileges. */
1841 	if (setgid(pw->pw_gid) == -1)
1842 		fatal("setgid %d failed", pw->pw_gid);
1843 	if (setuid(pw->pw_uid) == -1)
1844 		fatal("setuid %d failed", pw->pw_uid);
1845 
1846 	event_init();
1847 
1848 	switch (proc_id) {
1849 	case PROC_GOTD:
1850 #ifndef PROFILE
1851 		/* "exec" promise will be limited to argv[0] via unveil(2). */
1852 		if (pledge("stdio proc exec sendfd recvfd unveil", NULL) == -1)
1853 			err(1, "pledge");
1854 #endif
1855 		break;
1856 	case PROC_LISTEN:
1857 #ifndef PROFILE
1858 		if (pledge("stdio sendfd unix unveil", NULL) == -1)
1859 			err(1, "pledge");
1860 #endif
1861 		/*
1862 		 * Ensure that AF_UNIX bind(2) cannot be used with any other
1863 		 * sockets by revoking all filesystem access via unveil(2).
1864 		 */
1865 		apply_unveil_none();
1866 
1867 		listen_main(title, fd, gotd.connection_limits,
1868 		    gotd.nconnection_limits);
1869 		/* NOTREACHED */
1870 		break;
1871 	case PROC_AUTH:
1872 #ifndef PROFILE
1873 		if (pledge("stdio getpw recvfd unix unveil", NULL) == -1)
1874 			err(1, "pledge");
1875 #endif
1876 		/*
1877 		 * We need the "unix" pledge promise for getpeername(2) only.
1878 		 * Ensure that AF_UNIX bind(2) cannot be used by revoking all
1879 		 * filesystem access via unveil(2). Access to password database
1880 		 * files will still work since "getpw" bypasses unveil(2).
1881 		 */
1882 		apply_unveil_none();
1883 
1884 		auth_main(title, &gotd.repos, repo_path);
1885 		/* NOTREACHED */
1886 		break;
1887 	case PROC_SESSION:
1888 #ifndef PROFILE
1889 		/*
1890 		 * The "recvfd" promise is only needed during setup and
1891 		 * will be removed in a later pledge(2) call.
1892 		 */
1893 		if (pledge("stdio rpath wpath cpath recvfd sendfd fattr flock "
1894 		    "unveil", NULL) == -1)
1895 			err(1, "pledge");
1896 #endif
1897 		apply_unveil_repo_readwrite(repo_path);
1898 		session_main(title, repo_path, pack_fds, temp_fds,
1899 		    &gotd.request_timeout);
1900 		/* NOTREACHED */
1901 		break;
1902 	case PROC_REPO_READ:
1903 #ifndef PROFILE
1904 		if (pledge("stdio rpath recvfd unveil", NULL) == -1)
1905 			err(1, "pledge");
1906 #endif
1907 		apply_unveil_repo_readonly(repo_path);
1908 		repo_read_main(title, repo_path, pack_fds, temp_fds);
1909 		/* NOTREACHED */
1910 		exit(0);
1911 	case PROC_REPO_WRITE:
1912 #ifndef PROFILE
1913 		if (pledge("stdio rpath recvfd unveil", NULL) == -1)
1914 			err(1, "pledge");
1915 #endif
1916 		apply_unveil_repo_readonly(repo_path);
1917 		repo_write_main(title, repo_path, pack_fds, temp_fds);
1918 		/* NOTREACHED */
1919 		exit(0);
1920 	default:
1921 		fatal("invalid process id %d", proc_id);
1922 	}
1923 
1924 	if (proc_id != PROC_GOTD)
1925 		fatal("invalid process id %d", proc_id);
1926 
1927 	apply_unveil_selfexec();
1928 
1929 	signal_set(&evsigint, SIGINT, gotd_sighdlr, NULL);
1930 	signal_set(&evsigterm, SIGTERM, gotd_sighdlr, NULL);
1931 	signal_set(&evsighup, SIGHUP, gotd_sighdlr, NULL);
1932 	signal_set(&evsigusr1, SIGUSR1, gotd_sighdlr, NULL);
1933 	signal(SIGPIPE, SIG_IGN);
1934 
1935 	signal_add(&evsigint, NULL);
1936 	signal_add(&evsigterm, NULL);
1937 	signal_add(&evsighup, NULL);
1938 	signal_add(&evsigusr1, NULL);
1939 
1940 	gotd_imsg_event_add(&gotd.listen_proc.iev);
1941 
1942 	event_dispatch();
1943 
1944 	free(repo_path);
1945 	gotd_shutdown();
1946 
1947 	return 0;
1948 }