1 /*
2  * Copyright (c) 2021 Omar Polo <op@omarpolo.com>
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 "gmid.h"
18 
19 #include <sys/stat.h>
20 
21 #include <assert.h>
22 #include <ctype.h>
23 #include <errno.h>
24 #include <event.h>
25 #include <fcntl.h>
26 #include <fnmatch.h>
27 #include <limits.h>
28 #include <string.h>
29 
30 #define MIN(a, b)	((a) < (b) ? (a) : (b))
31 
32 int shutting_down;
33 
34 static struct tls	*ctx;
35 
36 static struct event e4, e6, imsgev, siginfo, sigusr2;
37 static int has_ipv6, has_siginfo;
38 
39 int connected_clients;
40 
41 static inline int matches(const char*, const char*);
42 
43 static int	 check_path(struct client*, const char*, int*);
44 static void	 open_file(struct client*);
45 static void	 check_for_cgi(struct client*);
46 static void	 handle_handshake(int, short, void*);
47 static const char *strip_path(const char*, int);
48 static void	 fmt_sbuf(const char*, struct client*, const char*);
49 static int	 apply_block_return(struct client*);
50 static int	 apply_reverse_proxy(struct client *);
51 static int	 apply_fastcgi(struct client*);
52 static int	 apply_require_ca(struct client*);
53 static size_t	 host_nth(struct vhost*);
54 static void	 start_cgi(const char*, const char*, struct client*);
55 static void	 open_dir(struct client*);
56 static void	 redirect_canonical_dir(struct client*);
57 
58 static void	 client_tls_readcb(int, short, void *);
59 static void	 client_tls_writecb(int, short, void *);
60 
61 static void	 client_read(struct bufferevent *, void *);
62 void		 client_write(struct bufferevent *, void *);
63 static void	 client_error(struct bufferevent *, short, void *);
64 
65 static void	 client_close_ev(int, short, void *);
66 
67 static void	 cgi_read(struct bufferevent *, void *);
68 static void	 cgi_write(struct bufferevent *, void *);
69 static void	 cgi_error(struct bufferevent *, short, void *);
70 
71 static void	 do_accept(int, short, void*);
72 static struct client *client_by_id(int);
73 
74 static void	 handle_imsg_cgi_res(struct imsgbuf*, struct imsg*, size_t);
75 static void	 handle_imsg_fcgi_fd(struct imsgbuf*, struct imsg*, size_t);
76 static void	 handle_imsg_conn_fd(struct imsgbuf*, struct imsg*, size_t);
77 static void	 handle_imsg_quit(struct imsgbuf*, struct imsg*, size_t);
78 static void	 handle_dispatch_imsg(int, short, void *);
79 static void	 handle_siginfo(int, short, void*);
80 
81 static imsg_handlerfn *handlers[] = {
82 	[IMSG_QUIT] = handle_imsg_quit,
83 	[IMSG_CGI_RES] = handle_imsg_cgi_res,
84 	[IMSG_FCGI_FD] = handle_imsg_fcgi_fd,
85 	[IMSG_CONN_FD] = handle_imsg_conn_fd,
86 };
87 
88 static uint32_t server_client_id;
89 
90 struct client_tree_id clients;
91 
92 static inline int
93 matches(const char *pattern, const char *path)
94 {
95 	if (*path == '/')
96 		path++;
97 	return !fnmatch(pattern, path, 0);
98 }
99 
100 const char *
101 vhost_lang(struct vhost *v, const char *path)
102 {
103 	struct location *loc;
104 
105 	if (v == NULL || path == NULL)
106 		return NULL;
107 
108 	loc = TAILQ_FIRST(&v->locations);
109 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
110 		if (loc->lang != NULL) {
111 			if (matches(loc->match, path))
112 				return loc->lang;
113 		}
114 	}
115 
116 	return TAILQ_FIRST(&v->locations)->lang;
117 }
118 
119 const char *
120 vhost_default_mime(struct vhost *v, const char *path)
121 {
122 	struct location *loc;
123 	const char *default_mime = "application/octet-stream";
124 
125 	if (v == NULL || path == NULL)
126 		return default_mime;
127 
128 	loc = TAILQ_FIRST(&v->locations);
129 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
130 		if (loc->default_mime != NULL) {
131 			if (matches(loc->match, path))
132 				return loc->default_mime;
133 		}
134 	}
135 
136 	loc = TAILQ_FIRST(&v->locations);
137 	if (loc->default_mime != NULL)
138 		return loc->default_mime;
139 	return default_mime;
140 }
141 
142 const char *
143 vhost_index(struct vhost *v, const char *path)
144 {
145 	struct location *loc;
146 	const char *index = "index.gmi";
147 
148 	if (v == NULL || path == NULL)
149 		return index;
150 
151 	loc = TAILQ_FIRST(&v->locations);
152 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
153 		if (loc->index != NULL) {
154 			if (matches(loc->match, path))
155 				return loc->index;
156 		}
157 	}
158 
159 	loc = TAILQ_FIRST(&v->locations);
160 	if (loc->index != NULL)
161 		return loc->index;
162 	return index;
163 }
164 
165 int
166 vhost_auto_index(struct vhost *v, const char *path)
167 {
168 	struct location *loc;
169 
170 	if (v == NULL || path == NULL)
171 		return 0;
172 
173 	loc = TAILQ_FIRST(&v->locations);
174 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
175 		if (loc->auto_index != 0) {
176 			if (matches(loc->match, path))
177 				return loc->auto_index == 1;
178 		}
179 	}
180 
181 	loc = TAILQ_FIRST(&v->locations);
182 	return loc->auto_index == 1;
183 }
184 
185 int
186 vhost_block_return(struct vhost *v, const char *path, int *code, const char **fmt)
187 {
188 	struct location *loc;
189 
190 	if (v == NULL || path == NULL)
191 		return 0;
192 
193 	loc = TAILQ_FIRST(&v->locations);
194 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
195 		if (loc->block_code != 0) {
196 			if (matches(loc->match, path)) {
197 				*code = loc->block_code;
198 				*fmt = loc->block_fmt;
199 				return 1;
200 			}
201 		}
202 	}
203 
204 	loc = TAILQ_FIRST(&v->locations);
205 	*code = loc->block_code;
206 	*fmt = loc->block_fmt;
207 	return loc->block_code != 0;
208 }
209 
210 int
211 vhost_fastcgi(struct vhost *v, const char *path)
212 {
213 	struct location *loc;
214 
215 	if (v == NULL || path == NULL)
216 		return -1;
217 
218 	loc = TAILQ_FIRST(&v->locations);
219 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
220 		if (loc->fcgi != -1)
221 			if (matches(loc->match, path))
222 				return loc->fcgi;
223 	}
224 
225 	loc = TAILQ_FIRST(&v->locations);
226 	return loc->fcgi;
227 }
228 
229 int
230 vhost_dirfd(struct vhost *v, const char *path, size_t *retloc)
231 {
232 	struct location *loc;
233 	size_t		 l = 0;
234 
235 	if (v == NULL || path == NULL)
236 		return -1;
237 
238 	loc = TAILQ_FIRST(&v->locations);
239 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
240 		l++;
241 		if (loc->dirfd != -1)
242 			if (matches(loc->match, path)) {
243 				*retloc = l;
244 				return loc->dirfd;
245 			}
246 	}
247 
248 	*retloc = 0;
249 	loc = TAILQ_FIRST(&v->locations);
250 	return loc->dirfd;
251 }
252 
253 int
254 vhost_strip(struct vhost *v, const char *path)
255 {
256 	struct location *loc;
257 
258 	if (v == NULL || path == NULL)
259 		return 0;
260 
261 	loc = TAILQ_FIRST(&v->locations);
262 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
263 		if (loc->strip != 0) {
264 			if (matches(loc->match, path))
265 				return loc->strip;
266 		}
267 	}
268 
269 	loc = TAILQ_FIRST(&v->locations);
270 	return loc->strip;
271 }
272 
273 X509_STORE *
274 vhost_require_ca(struct vhost *v, const char *path)
275 {
276 	struct location *loc;
277 
278 	if (v == NULL || path == NULL)
279 		return NULL;
280 
281 	loc = TAILQ_FIRST(&v->locations);
282 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
283 		if (loc->reqca != NULL) {
284 			if (matches(loc->match, path))
285 				return loc->reqca;
286 		}
287 	}
288 
289 	loc = TAILQ_FIRST(&v->locations);
290 	return loc->reqca;
291 }
292 
293 int
294 vhost_disable_log(struct vhost *v, const char *path)
295 {
296 	struct location *loc;
297 
298 	if (v == NULL || path == NULL)
299 		return 0;
300 
301 	loc = TAILQ_FIRST(&v->locations);
302 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
303 		if (loc->disable_log && matches(loc->match, path))
304 				return 1;
305 	}
306 
307 	loc = TAILQ_FIRST(&v->locations);
308 	return loc->disable_log;
309 }
310 
311 static int
312 check_path(struct client *c, const char *path, int *fd)
313 {
314 	struct stat sb;
315 	const char *p;
316 	int dirfd, strip;
317 
318 	assert(path != NULL);
319 
320 	/*
321 	 * in send_dir we add an initial / (to be redirect-friendly),
322 	 * but here we want to skip it
323 	 */
324 	if (*path == '/')
325 		path++;
326 
327 	strip = vhost_strip(c->host, path);
328 	p = strip_path(path, strip);
329 
330 	if (*p == '/')
331 		p = p+1;
332 	if (*p == '\0')
333 		p = ".";
334 
335 	dirfd = vhost_dirfd(c->host, path, &c->loc);
336 	log_debug(c, "check_path: strip=%d path=%s original=%s",
337 	    strip, p, path);
338 	if (*fd == -1 && (*fd = openat(dirfd, p, O_RDONLY)) == -1)
339 		return FILE_MISSING;
340 
341 	if (fstat(*fd, &sb) == -1) {
342 		log_notice(c, "failed stat for %s: %s", path, strerror(errno));
343 		return FILE_MISSING;
344 	}
345 
346 	if (S_ISDIR(sb.st_mode))
347 		return FILE_DIRECTORY;
348 
349 	if (sb.st_mode & S_IXUSR)
350 		return FILE_EXECUTABLE;
351 
352 	return FILE_EXISTS;
353 }
354 
355 static void
356 open_file(struct client *c)
357 {
358 	switch (check_path(c, c->iri.path, &c->pfd)) {
359 	case FILE_EXECUTABLE:
360 		if (c->host->cgi != NULL && matches(c->host->cgi, c->iri.path)) {
361 			start_cgi(c->iri.path, "", c);
362 			return;
363 		}
364 
365 		/* fallthrough */
366 
367 	case FILE_EXISTS:
368 		c->type = REQUEST_FILE;
369 		start_reply(c, SUCCESS, mime(c->host, c->iri.path));
370 		return;
371 
372 	case FILE_DIRECTORY:
373 		open_dir(c);
374 		return;
375 
376 	case FILE_MISSING:
377 		if (c->host->cgi != NULL && matches(c->host->cgi, c->iri.path)) {
378 			check_for_cgi(c);
379 			return;
380 		}
381 		start_reply(c, NOT_FOUND, "not found");
382 		return;
383 
384 	default:
385 		/* unreachable */
386 		abort();
387 	}
388 }
389 
390 /*
391  * the inverse of this algorithm, i.e. starting from the start of the
392  * path + strlen(cgi), and checking if each component, should be
393  * faster.  But it's tedious to write.  This does the opposite: starts
394  * from the end and strip one component at a time, until either an
395  * executable is found or we emptied the path.
396  */
397 static void
398 check_for_cgi(struct client *c)
399 {
400 	char path[PATH_MAX];
401 	char *end;
402 
403 	strlcpy(path, c->iri.path, sizeof(path));
404 	end = strchr(path, '\0');
405 
406 	while (end > path) {
407 		/*
408 		 * go up one level.  UNIX paths are simple and POSIX
409 		 * dirname, with its ambiguities on if the given
410 		 * pointer is changed or not, gives me headaches.
411 		 */
412 		while (*end != '/' && end > path)
413 			end--;
414 
415 		if (end == path)
416 			break;
417 
418 		*end = '\0';
419 
420 		switch (check_path(c, path, &c->pfd)) {
421 		case FILE_EXECUTABLE:
422 			start_cgi(path, end+1, c);
423 			return;
424 		case FILE_MISSING:
425 			break;
426 		default:
427 			goto err;
428 		}
429 
430 		*end = '/';
431 		end--;
432 	}
433 
434 err:
435 	start_reply(c, NOT_FOUND, "not found");
436 	return;
437 }
438 
439 void
440 mark_nonblock(int fd)
441 {
442 	int flags;
443 
444 	if ((flags = fcntl(fd, F_GETFL)) == -1)
445 		fatal("fcntl(F_GETFL): %s", strerror(errno));
446 	if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1)
447 		fatal("fcntl(F_SETFL): %s", strerror(errno));
448 }
449 
450 static void
451 handle_handshake(int fd, short ev, void *d)
452 {
453 	struct client *c = d;
454 	struct vhost *h;
455 	struct alist *a;
456 	const char *servname;
457 	const char *parse_err = "unknown error";
458 
459 	switch (tls_handshake(c->ctx)) {
460 	case 0:  /* success */
461 	case -1: /* already handshaked */
462 		break;
463 	case TLS_WANT_POLLIN:
464 		event_once(c->fd, EV_READ, handle_handshake, c, NULL);
465 		return;
466 	case TLS_WANT_POLLOUT:
467 		event_once(c->fd, EV_WRITE, handle_handshake, c, NULL);
468 		return;
469 	default:
470 		/* unreachable */
471 		abort();
472 	}
473 
474 	c->bev = bufferevent_new(fd, client_read, client_write,
475 	    client_error, c);
476 	if (c->bev == NULL)
477 		fatal("%s: failed to allocate client buffer: %s",
478 		    __func__, strerror(errno));
479 
480 	event_set(&c->bev->ev_read, c->fd, EV_READ,
481 	    client_tls_readcb, c->bev);
482 	event_set(&c->bev->ev_write, c->fd, EV_WRITE,
483 	    client_tls_writecb, c->bev);
484 
485 #if HAVE_LIBEVENT2
486 	evbuffer_unfreeze(c->bev->input, 0);
487 	evbuffer_unfreeze(c->bev->output, 1);
488 #endif
489 
490 	if ((servname = tls_conn_servername(c->ctx)) == NULL) {
491 		log_debug(c, "handshake: missing SNI");
492 		goto err;
493 	}
494 
495 	if (!puny_decode(servname, c->domain, sizeof(c->domain), &parse_err)) {
496 		log_info(c, "puny_decode: %s", parse_err);
497 		goto err;
498 	}
499 
500 	TAILQ_FOREACH(h, &hosts, vhosts) {
501 		if (matches(h->domain, c->domain))
502 			goto found;
503 		TAILQ_FOREACH(a, &h->aliases, aliases) {
504 			if (matches(a->alias, c->domain))
505 				goto found;
506 		}
507 	}
508 
509 found:
510 	log_debug(c, "handshake: SNI: \"%s\"; decoded: \"%s\"; matched: \"%s\"",
511 	    servname != NULL ? servname : "(null)",
512 	    c->domain,
513 	    h != NULL ? h->domain : "(null)");
514 
515 	if (h != NULL) {
516 		c->host = h;
517 		bufferevent_enable(c->bev, EV_READ);
518 		return;
519 	}
520 
521 err:
522 	start_reply(c, BAD_REQUEST, "Wrong/malformed host or missing SNI");
523 }
524 
525 static const char *
526 strip_path(const char *path, int strip)
527 {
528 	char *t;
529 
530 	while (strip > 0) {
531 		if ((t = strchr(path, '/')) == NULL) {
532 			path = strchr(path, '\0');
533 			break;
534 		}
535 		path = t;
536 		strip--;
537 	}
538 
539 	return path;
540 }
541 
542 static void
543 fmt_sbuf(const char *fmt, struct client *c, const char *path)
544 {
545 	size_t i;
546 	char buf[32];
547 
548 	memset(buf, 0, sizeof(buf));
549 	for (i = 0; *fmt; ++fmt) {
550 		if (i == sizeof(buf)-1 || *fmt == '%') {
551 			strlcat(c->sbuf, buf, sizeof(c->sbuf));
552 			memset(buf, 0, sizeof(buf));
553 			i = 0;
554 		}
555 
556 		if (*fmt != '%') {
557 			buf[i++] = *fmt;
558 			continue;
559 		}
560 
561 		switch (*++fmt) {
562 		case '%':
563 			strlcat(c->sbuf, "%", sizeof(c->sbuf));
564 			break;
565 		case 'p':
566 			if (*path != '/')
567 				strlcat(c->sbuf, "/", sizeof(c->sbuf));
568 			strlcat(c->sbuf, path, sizeof(c->sbuf));
569 			break;
570 		case 'q':
571 			strlcat(c->sbuf, c->iri.query, sizeof(c->sbuf));
572 			break;
573 		case 'P':
574 			snprintf(buf, sizeof(buf), "%d", conf.port);
575 			strlcat(c->sbuf, buf, sizeof(c->sbuf));
576 			memset(buf, 0, sizeof(buf));
577 			break;
578 		case 'N':
579 			strlcat(c->sbuf, c->domain, sizeof(c->sbuf));
580 			break;
581 		default:
582 			fatal("%s: unknown fmt specifier %c",
583 			    __func__, *fmt);
584 		}
585 	}
586 
587 	if (i != 0)
588 		strlcat(c->sbuf, buf, sizeof(c->sbuf));
589 }
590 
591 /* 1 if a matching `block return' (and apply it), 0 otherwise */
592 static int
593 apply_block_return(struct client *c)
594 {
595 	const char *fmt, *path;
596 	int code;
597 
598 	if (!vhost_block_return(c->host, c->iri.path, &code, &fmt))
599 		return 0;
600 
601 	path = strip_path(c->iri.path, vhost_strip(c->host, c->iri.path));
602 	fmt_sbuf(fmt, c, path);
603 
604 	start_reply(c, code, c->sbuf);
605 	return 1;
606 }
607 
608 static struct proxy *
609 matched_proxy(struct client *c)
610 {
611 	struct proxy	*p;
612 	const char	*proto;
613 	const char	*host;
614 	const char	*port;
615 
616 	TAILQ_FOREACH(p, &c->host->proxies, proxies) {
617 		if ((proto = p->match_proto) == NULL)
618 			proto = "gemini";
619 		if ((host = p->match_host) == NULL)
620 			host = "*";
621 		if ((port = p->match_port) == NULL)
622 			port = "*";
623 
624 		if (matches(proto, c->iri.schema) &&
625 		    matches(host, c->domain) &&
626 		    matches(port, c->iri.port))
627 			return p;
628 	}
629 
630 	return NULL;
631 }
632 
633 /* 1 if matching a proxy relay-to (and apply it), 0 otherwise */
634 static int
635 apply_reverse_proxy(struct client *c)
636 {
637 	struct proxy	*p;
638 	struct connreq	 r;
639 
640 	if ((p = matched_proxy(c)) == NULL)
641 		return 0;
642 
643 	c->proxy = p;
644 
645 	log_debug(c, "opening proxy connection for %s:%s",
646 	    p->host, p->port);
647 
648 	strlcpy(r.host, p->host, sizeof(r.host));
649 	strlcpy(r.port, p->port, sizeof(r.port));
650 
651 	imsg_compose(&exibuf, IMSG_CONN_REQ, c->id, 0, -1, &r, sizeof(r));
652 	imsg_flush(&exibuf);
653 
654 	return 1;
655 }
656 
657 /* 1 if matching `fcgi' (and apply it), 0 otherwise */
658 static int
659 apply_fastcgi(struct client *c)
660 {
661 	int		 id;
662 	struct fcgi	*f;
663 
664 	if ((id = vhost_fastcgi(c->host, c->iri.path)) == -1)
665 		return 0;
666 
667 	f = &fcgi[id];
668 
669 	log_debug(c, "opening fastcgi connection for (%s,%s,%s)",
670 	    f->path, f->port, f->prog);
671 
672 	imsg_compose(&exibuf, IMSG_FCGI_REQ, c->id, 0, -1,
673 	    &id, sizeof(id));
674 	imsg_flush(&exibuf);
675 	return 1;
676 }
677 
678 /* 1 if matching `require client ca' fails (and apply it), 0 otherwise */
679 static int
680 apply_require_ca(struct client *c)
681 {
682 	X509_STORE	*store;
683 	const uint8_t	*cert;
684 	size_t		 len;
685 
686 	if ((store = vhost_require_ca(c->host, c->iri.path)) == NULL)
687 		return 0;
688 
689 	if (!tls_peer_cert_provided(c->ctx)) {
690 		start_reply(c, CLIENT_CERT_REQ, "client certificate required");
691 		return 1;
692 	}
693 
694 	cert = tls_peer_cert_chain_pem(c->ctx, &len);
695 	if (!validate_against_ca(store, cert, len)) {
696 		start_reply(c, CERT_NOT_AUTH, "certificate not authorised");
697 		return 1;
698 	}
699 
700 	return 0;
701 }
702 
703 static size_t
704 host_nth(struct vhost *h)
705 {
706 	struct vhost	*v;
707 	size_t		 i = 0;
708 
709 	TAILQ_FOREACH(v, &hosts, vhosts) {
710 		if (v == h)
711 			return i;
712 		i++;
713 	}
714 
715 	abort();
716 }
717 
718 static void
719 start_cgi(const char *spath, const char *relpath, struct client *c)
720 {
721 	char addr[NI_MAXHOST];
722 	const char *t;
723 	struct cgireq req;
724 	int e;
725 
726 	c->type = REQUEST_CGI;
727 
728 	e = getnameinfo((struct sockaddr*)&c->addr, sizeof(c->addr),
729 	    addr, sizeof(addr),
730 	    NULL, 0,
731 	    NI_NUMERICHOST);
732 	if (e != 0)
733 		fatal("getnameinfo failed");
734 
735 	memset(&req, 0, sizeof(req));
736 
737 	memcpy(req.buf, c->req, sizeof(req.buf));
738 
739 	req.iri_schema_off = c->iri.schema - c->req;
740 	req.iri_host_off = c->iri.host - c->req;
741 	req.iri_port_off = c->iri.port - c->req;
742 	req.iri_path_off = c->iri.path - c->req;
743 	req.iri_query_off = c->iri.query - c->req;
744 	req.iri_fragment_off = c->iri.fragment - c->req;
745 
746 	req.iri_portno = c->iri.port_no;
747 
748 	strlcpy(req.spath, spath, sizeof(req.spath));
749 	strlcpy(req.relpath, relpath, sizeof(req.relpath));
750 	strlcpy(req.addr, addr, sizeof(req.addr));
751 
752 	if ((t = tls_peer_cert_subject(c->ctx)) != NULL)
753 		strlcpy(req.subject, t, sizeof(req.subject));
754 	if ((t = tls_peer_cert_issuer(c->ctx)) != NULL)
755 		strlcpy(req.issuer, t, sizeof(req.issuer));
756 	if ((t = tls_peer_cert_hash(c->ctx)) != NULL)
757 		strlcpy(req.hash, t, sizeof(req.hash));
758 	if ((t = tls_conn_version(c->ctx)) != NULL)
759 		strlcpy(req.version, t, sizeof(req.version));
760 	if ((t = tls_conn_cipher(c->ctx)) != NULL)
761 		strlcpy(req.cipher, t, sizeof(req.cipher));
762 
763 	req.cipher_strength = tls_conn_cipher_strength(c->ctx);
764 	req.notbefore = tls_peer_cert_notbefore(c->ctx);
765 	req.notafter = tls_peer_cert_notafter(c->ctx);
766 
767 	req.host_off = host_nth(c->host);
768 	req.loc_off = c->loc;
769 
770 	imsg_compose(&exibuf, IMSG_CGI_REQ, c->id, 0, -1, &req, sizeof(req));
771 	imsg_flush(&exibuf);
772 
773 	close(c->pfd);
774 }
775 
776 static void
777 open_dir(struct client *c)
778 {
779 	size_t len;
780 	int dirfd, root;
781 	char *before_file;
782 
783 	root = !strcmp(c->iri.path, "/") || *c->iri.path == '\0';
784 
785 	len = strlen(c->iri.path);
786 	if (len > 0 && !ends_with(c->iri.path, "/")) {
787 		redirect_canonical_dir(c);
788 		return;
789 	}
790 
791 	strlcpy(c->sbuf, "/", sizeof(c->sbuf));
792 	strlcat(c->sbuf, c->iri.path, sizeof(c->sbuf));
793 	if (!ends_with(c->sbuf, "/"))
794 		strlcat(c->sbuf, "/", sizeof(c->sbuf));
795 	before_file = strchr(c->sbuf, '\0');
796 	len = strlcat(c->sbuf, vhost_index(c->host, c->iri.path),
797 	    sizeof(c->sbuf));
798 	if (len >= sizeof(c->sbuf)) {
799 		start_reply(c, TEMP_FAILURE, "internal server error");
800 		return;
801 	}
802 
803 	c->iri.path = c->sbuf;
804 
805 	/* close later unless we have to generate the dir listing */
806 	dirfd = c->pfd;
807 	c->pfd = -1;
808 
809 	switch (check_path(c, c->iri.path, &c->pfd)) {
810 	case FILE_EXECUTABLE:
811 		if (c->host->cgi != NULL && matches(c->host->cgi, c->iri.path)) {
812 			start_cgi(c->iri.path, "", c);
813 			break;
814 		}
815 
816 		/* fallthrough */
817 
818 	case FILE_EXISTS:
819 		c->type = REQUEST_FILE;
820 		start_reply(c, SUCCESS, mime(c->host, c->iri.path));
821 		break;
822 
823 	case FILE_DIRECTORY:
824 		start_reply(c, TEMP_REDIRECT, c->sbuf);
825 		break;
826 
827 	case FILE_MISSING:
828 		*before_file = '\0';
829 
830 		if (!vhost_auto_index(c->host, c->iri.path)) {
831 			start_reply(c, NOT_FOUND, "not found");
832 			break;
833 		}
834 
835 		c->type = REQUEST_DIR;
836 
837 		c->dirlen = scandir_fd(dirfd, &c->dir,
838 		    root ? select_non_dotdot : select_non_dot,
839 		    alphasort);
840 		if (c->dirlen == -1) {
841 			log_err(c, "scandir_fd(%d) (vhost:%s) %s: %s",
842 			    c->pfd, c->host->domain, c->iri.path, strerror(errno));
843 			start_reply(c, TEMP_FAILURE, "internal server error");
844 			return;
845 		}
846 		c->diroff = 0;
847 		c->off = 0;
848 
849 		start_reply(c, SUCCESS, "text/gemini");
850 		evbuffer_add_printf(EVBUFFER_OUTPUT(c->bev),
851 		    "# Index of %s\n\n", c->iri.path);
852 		return;
853 
854 	default:
855 		/* unreachable */
856 		abort();
857 	}
858 
859 	close(dirfd);
860 }
861 
862 static void
863 redirect_canonical_dir(struct client *c)
864 {
865 	size_t len;
866 
867 	strlcpy(c->sbuf, "/", sizeof(c->sbuf));
868 	strlcat(c->sbuf, c->iri.path, sizeof(c->sbuf));
869 	len = strlcat(c->sbuf, "/", sizeof(c->sbuf));
870 
871 	if (len >= sizeof(c->sbuf)) {
872 		start_reply(c, TEMP_FAILURE, "internal server error");
873 		return;
874 	}
875 
876 	start_reply(c, TEMP_REDIRECT, c->sbuf);
877 }
878 
879 static void
880 client_tls_readcb(int fd, short event, void *d)
881 {
882 	struct bufferevent	*bufev = d;
883 	struct client		*client = bufev->cbarg;
884 	ssize_t			 ret;
885 	size_t			 len;
886 	int			 what = EVBUFFER_READ;
887 	int			 howmuch = IBUF_READ_SIZE;
888 	char			 buf[IBUF_READ_SIZE];
889 
890 	if (event == EV_TIMEOUT) {
891 		what |= EVBUFFER_TIMEOUT;
892 		goto err;
893 	}
894 
895 	if (bufev->wm_read.high != 0)
896 		howmuch = MIN(sizeof(buf), bufev->wm_read.high);
897 
898 	switch (ret = tls_read(client->ctx, buf, howmuch)) {
899 	case TLS_WANT_POLLIN:
900 	case TLS_WANT_POLLOUT:
901 		goto retry;
902 	case -1:
903 		what |= EVBUFFER_ERROR;
904 		goto err;
905 	}
906 	len = ret;
907 
908 	if (len == 0) {
909 		what |= EVBUFFER_EOF;
910 		goto err;
911 	}
912 
913 	if (evbuffer_add(bufev->input, buf, len) == -1) {
914 		what |= EVBUFFER_ERROR;
915 		goto err;
916 	}
917 
918 	event_add(&bufev->ev_read, NULL);
919 	if (bufev->wm_read.low != 0 && len < bufev->wm_read.low)
920 		return;
921 	if (bufev->wm_read.high != 0 && len > bufev->wm_read.high) {
922 		/*
923 		 * here we could implement a read pressure policy.
924 		 */
925 	}
926 
927 	if (bufev->readcb != NULL)
928 		(*bufev->readcb)(bufev, bufev->cbarg);
929 
930 	return;
931 
932 retry:
933 	event_add(&bufev->ev_read, NULL);
934 	return;
935 
936 err:
937 	(*bufev->errorcb)(bufev, what, bufev->cbarg);
938 }
939 
940 static void
941 client_tls_writecb(int fd, short event, void *d)
942 {
943 	struct bufferevent	*bufev = d;
944 	struct client		*client = bufev->cbarg;
945 	ssize_t			 ret;
946 	size_t			 len;
947 	short			 what = EVBUFFER_WRITE;
948 
949 	if (event == EV_TIMEOUT) {
950 		what |= EVBUFFER_TIMEOUT;
951 		goto err;
952 	}
953 
954 	if (EVBUFFER_LENGTH(bufev->output) != 0) {
955 		ret = tls_write(client->ctx,
956 		    EVBUFFER_DATA(bufev->output),
957 		    EVBUFFER_LENGTH(bufev->output));
958 		switch (ret) {
959 		case TLS_WANT_POLLIN:
960 		case TLS_WANT_POLLOUT:
961 			goto retry;
962 		case -1:
963 			what |= EVBUFFER_ERROR;
964 			goto err;
965 		}
966 		len = ret;
967 		evbuffer_drain(bufev->output, len);
968 	}
969 
970 	if (EVBUFFER_LENGTH(bufev->output) != 0)
971 		event_add(&bufev->ev_write, NULL);
972 
973 	if (bufev->writecb != NULL &&
974 	    EVBUFFER_LENGTH(bufev->output) <= bufev->wm_write.low)
975 		(*bufev->writecb)(bufev, bufev->cbarg);
976 	return;
977 
978 retry:
979 	event_add(&bufev->ev_write, NULL);
980 	return;
981 err:
982 	log_err(client, "tls error: %s", tls_error(client->ctx));
983 	(*bufev->errorcb)(bufev, what, bufev->cbarg);
984 }
985 
986 static void
987 client_read(struct bufferevent *bev, void *d)
988 {
989 	struct client	*c = d;
990 	struct evbuffer	*src = EVBUFFER_INPUT(bev);
991 	const char	*parse_err = "invalid request";
992 	char		 decoded[DOMAIN_NAME_LEN];
993 	size_t		 len;
994 
995 	bufferevent_disable(bev, EVBUFFER_READ);
996 
997 	/* max url len + \r\n */
998 	if (EVBUFFER_LENGTH(src) > 1024 + 2) {
999 		log_err(c, "too much data received");
1000 		start_reply(c, BAD_REQUEST, "bad request");
1001 		return;
1002 	}
1003 
1004 	c->req = evbuffer_readln(src, &len, EVBUFFER_EOL_CRLF_STRICT);
1005 	if (c->req == NULL) {
1006 		/* not enough data yet. */
1007 		bufferevent_enable(bev, EVBUFFER_READ);
1008 		return;
1009 	}
1010 
1011 	if (!parse_iri(c->req, &c->iri, &parse_err) ||
1012 	    !puny_decode(c->iri.host, decoded, sizeof(decoded), &parse_err)) {
1013 		log_err(c, "IRI parse error: %s", parse_err);
1014 		start_reply(c, BAD_REQUEST, "bad request");
1015 		return;
1016 	}
1017 
1018 	if (apply_reverse_proxy(c))
1019 		return;
1020 
1021 	/* ignore the port number */
1022 	if (strcmp(c->iri.schema, "gemini") ||
1023 	    strcmp(decoded, c->domain)) {
1024 		start_reply(c, PROXY_REFUSED, "won't proxy request");
1025 		return;
1026 	}
1027 
1028 	if (apply_require_ca(c) ||
1029 	    apply_block_return(c)||
1030 	    apply_fastcgi(c))
1031 		return;
1032 
1033 	if (c->host->entrypoint != NULL) {
1034 		c->loc = 0;
1035 		start_cgi(c->host->entrypoint, c->iri.path, c);
1036 		return;
1037 	}
1038 
1039 	open_file(c);
1040 }
1041 
1042 void
1043 client_write(struct bufferevent *bev, void *d)
1044 {
1045 	struct client	*c = d;
1046 	struct evbuffer	*out = EVBUFFER_OUTPUT(bev);
1047 	char		 buf[BUFSIZ];
1048 	ssize_t		 r;
1049 
1050 	switch (c->type) {
1051 	case REQUEST_UNDECIDED:
1052 		/*
1053 		 * Ignore spurious calls when we still don't have idea
1054 		 * what to do with the request.
1055 		 */
1056 		break;
1057 
1058 	case REQUEST_FILE:
1059 		if ((r = read(c->pfd, buf, sizeof(buf))) == -1) {
1060 			log_warn(c, "read: %s", strerror(errno));
1061 			client_error(bev, EVBUFFER_ERROR, c);
1062 			return;
1063 		} else if (r == 0) {
1064 			client_close(c);
1065 			return;
1066 		} else if (r != sizeof(buf))
1067 			c->type = REQUEST_DONE;
1068 		bufferevent_write(bev, buf, r);
1069 		break;
1070 
1071 	case REQUEST_DIR:
1072 		/* TODO: handle big big directories better */
1073 		for (c->diroff = 0; c->diroff < c->dirlen; ++c->diroff) {
1074 			evbuffer_add_printf(out, "=> %s\n",
1075 			    c->dir[c->diroff]->d_name);
1076 			free(c->dir[c->diroff]);
1077 		}
1078 		free(c->dir);
1079 		c->dir = NULL;
1080 
1081 		c->type = REQUEST_DONE;
1082 
1083 		event_add(&c->bev->ev_write, NULL);
1084 		break;
1085 
1086 	case REQUEST_CGI:
1087 	case REQUEST_FCGI:
1088 	case REQUEST_PROXY:
1089 		/*
1090 		 *  Here we depend on on the cgi script or fastcgi
1091 		 *  connection to provide data.
1092 		 */
1093 		break;
1094 
1095 	case REQUEST_DONE:
1096 		if (EVBUFFER_LENGTH(out) == 0)
1097 			client_close(c);
1098 		break;
1099 	}
1100 }
1101 
1102 static void
1103 client_error(struct bufferevent *bev, short error, void *d)
1104 {
1105 	struct client	*c = d;
1106 
1107 	c->type = REQUEST_DONE;
1108 
1109 	if (error & EVBUFFER_TIMEOUT) {
1110 		log_warn(c, "timeout reached, "
1111 		    "forcefully closing the connection");
1112 		if (c->code == 0)
1113 			start_reply(c, BAD_REQUEST, "timeout");
1114 		else
1115 			client_close(c);
1116 		return;
1117 	}
1118 
1119 	if (error & EVBUFFER_EOF) {
1120 		client_close(c);
1121 		return;
1122 	}
1123 
1124 	log_err(c, "unknown bufferevent error: %s", strerror(errno));
1125 	client_close(c);
1126 }
1127 
1128 void
1129 start_reply(struct client *c, int code, const char *meta)
1130 {
1131 	struct evbuffer	*evb = EVBUFFER_OUTPUT(c->bev);
1132 	const char	*lang;
1133 	int		 r, rr;
1134 
1135 	bufferevent_enable(c->bev, EVBUFFER_WRITE);
1136 
1137 	c->code = code;
1138 	c->meta = meta;
1139 
1140 	r = evbuffer_add_printf(evb, "%d %s", code, meta);
1141 	if (r == -1)
1142 		goto err;
1143 
1144 	/* 2 digit status + space + 1024 max reply */
1145 	if (r > 1027)
1146 		goto overflow;
1147 
1148 	if (c->type != REQUEST_CGI &&
1149 	    c->type != REQUEST_FCGI &&
1150 	    c->type != REQUEST_PROXY &&
1151 	    !strcmp(meta, "text/gemini") &&
1152 	    (lang = vhost_lang(c->host, c->iri.path)) != NULL) {
1153 		rr = evbuffer_add_printf(evb, ";lang=%s", lang);
1154 		if (rr == -1)
1155 			goto err;
1156 		if (r + rr > 1027)
1157 			goto overflow;
1158 	}
1159 
1160 	bufferevent_write(c->bev, "\r\n", 2);
1161 
1162 	if (!vhost_disable_log(c->host, c->iri.path))
1163 		log_request(c, EVBUFFER_DATA(evb), EVBUFFER_LENGTH(evb));
1164 
1165 	if (code != 20 && IS_INTERNAL_REQUEST(c->type))
1166 		c->type = REQUEST_DONE;
1167 
1168 	return;
1169 
1170 err:
1171 	log_err(c, "evbuffer_add_printf error: no memory");
1172 	evbuffer_drain(evb, EVBUFFER_LENGTH(evb));
1173 	client_close(c);
1174 	return;
1175 
1176 overflow:
1177 	log_warn(c, "reply header overflow");
1178 	evbuffer_drain(evb, EVBUFFER_LENGTH(evb));
1179 	start_reply(c, TEMP_FAILURE, "internal error");
1180 }
1181 
1182 static void
1183 client_close_ev(int fd, short event, void *d)
1184 {
1185 	struct client	*c = d;
1186 
1187 	switch (tls_close(c->ctx)) {
1188 	case TLS_WANT_POLLIN:
1189 		event_once(c->fd, EV_READ, client_close_ev, c, NULL);
1190 		break;
1191 	case TLS_WANT_POLLOUT:
1192 		event_once(c->fd, EV_WRITE, client_close_ev, c, NULL);
1193 		break;
1194 	}
1195 
1196 	connected_clients--;
1197 
1198 	free(c->req);
1199 
1200 	tls_free(c->ctx);
1201 	c->ctx = NULL;
1202 
1203 	free(c->header);
1204 
1205 	if (c->pfd != -1)
1206 		close(c->pfd);
1207 
1208 	if (c->dir != NULL)
1209 		free(c->dir);
1210 
1211 	close(c->fd);
1212 	c->fd = -1;
1213 }
1214 
1215 static void
1216 client_proxy_close(int fd, short event, void *d)
1217 {
1218 	struct tls *ctx = d;
1219 
1220 	if (ctx == NULL) {
1221 		close(fd);
1222 		return;
1223 	}
1224 
1225 	switch (tls_close(ctx)) {
1226 	case TLS_WANT_POLLIN:
1227 		event_once(fd, EV_READ, client_proxy_close, d, NULL);
1228 		break;
1229 	case TLS_WANT_POLLOUT:
1230 		event_once(fd, EV_WRITE, client_proxy_close, d, NULL);
1231 		break;
1232 	}
1233 
1234 	tls_free(ctx);
1235 	close(fd);
1236 }
1237 
1238 void
1239 client_close(struct client *c)
1240 {
1241 	/*
1242 	 * We may end up calling client_close in various situations
1243 	 * and for the most unexpected reasons.  Therefore, we need to
1244 	 * ensure that everything is properly released once we reach
1245 	 * this point.
1246 	 */
1247 
1248 	SPLAY_REMOVE(client_tree_id, &clients, c);
1249 
1250 	if (c->cgibev != NULL) {
1251 		bufferevent_disable(c->cgibev, EVBUFFER_READ|EVBUFFER_WRITE);
1252 		bufferevent_free(c->cgibev);
1253 		c->cgibev = NULL;
1254 		close(c->pfd);
1255 		c->pfd = -1;
1256 	}
1257 
1258 	bufferevent_disable(c->bev, EVBUFFER_READ|EVBUFFER_WRITE);
1259 	bufferevent_free(c->bev);
1260 	c->bev = NULL;
1261 
1262 	if (c->proxybev != NULL) {
1263 		if (event_pending(&c->proxyev, EV_READ|EV_WRITE, NULL))
1264 			event_del(&c->proxyev);
1265 
1266 		if (c->pfd != -1 && c->proxyctx != NULL) {
1267 			/* shut down the proxy TLS connection */
1268 			client_proxy_close(c->pfd, 0, c->proxyctx);
1269 			c->pfd = -1;
1270 		}
1271 
1272 		bufferevent_free(c->proxybev);
1273 	}
1274 
1275 	client_close_ev(c->fd, 0, c);
1276 }
1277 
1278 static void
1279 cgi_read(struct bufferevent *bev, void *d)
1280 {
1281 	struct client	*client = d;
1282 	struct evbuffer	*src = EVBUFFER_INPUT(bev);
1283 	char		*header;
1284 	size_t		 len;
1285 	int		 code;
1286 
1287 	/* intercept the header */
1288 	if (client->code == 0) {
1289 		header = evbuffer_readln(src, &len, EVBUFFER_EOL_CRLF_STRICT);
1290 		if (header == NULL) {
1291 			/* max reply + \r\n */
1292 			if (EVBUFFER_LENGTH(src) > 1029) {
1293 				log_warn(client, "CGI script is trying to "
1294 				    "send a header too long.");
1295 				cgi_error(bev, EVBUFFER_READ, client);
1296 			}
1297 
1298 			/* wait a bit */
1299 			return;
1300 		}
1301 
1302 		if (len < 3 || len > 1029 ||
1303 		    !isdigit(header[0]) ||
1304 		    !isdigit(header[1]) ||
1305 		    !isspace(header[2])) {
1306 			free(header);
1307 			log_warn(client, "CGI script is trying to send a "
1308 			    "malformed header");
1309 			cgi_error(bev, EVBUFFER_READ, client);
1310 			return;
1311 		}
1312 
1313 		client->header = header;
1314 		code = (header[0] - '0') * 10 + (header[1] - '0');
1315 
1316 		if (code < 10 || code >= 70) {
1317 			log_warn(client, "CGI script is trying to send an "
1318 			    "invalid reply code (%d)", code);
1319 			cgi_error(bev, EVBUFFER_READ, client);
1320 			return;
1321 		}
1322 
1323 		start_reply(client, code, header + 3);
1324 
1325 		if (client->code < 20 || client->code > 29) {
1326 			cgi_error(client->cgibev, EVBUFFER_EOF, client);
1327 			return;
1328 		}
1329 	}
1330 
1331 	bufferevent_write_buffer(client->bev, src);
1332 }
1333 
1334 static void
1335 cgi_write(struct bufferevent *bev, void *d)
1336 {
1337 	/*
1338 	 * Never called.  We don't send data to a CGI script.
1339 	 */
1340 	abort();
1341 }
1342 
1343 static void
1344 cgi_error(struct bufferevent *bev, short error, void *d)
1345 {
1346 	struct client	*client = d;
1347 
1348 	if (error & EVBUFFER_ERROR)
1349 		log_err(client, "%s: evbuffer error (%x): %s",
1350 		    __func__, error, strerror(errno));
1351 
1352 	bufferevent_disable(bev, EVBUFFER_READ|EVBUFFER_WRITE);
1353 	bufferevent_free(bev);
1354 	client->cgibev = NULL;
1355 
1356 	close(client->pfd);
1357 	client->pfd = -1;
1358 
1359 	client->type = REQUEST_DONE;
1360 	if (client->code != 0)
1361 		client_write(client->bev, client);
1362 	else
1363 		start_reply(client, CGI_ERROR, "CGI error");
1364 }
1365 
1366 static void
1367 do_accept(int sock, short et, void *d)
1368 {
1369 	struct client *c;
1370 	struct sockaddr_storage addr;
1371 	struct sockaddr *saddr;
1372 	socklen_t len;
1373 	int fd;
1374 
1375 	saddr = (struct sockaddr*)&addr;
1376 	len = sizeof(addr);
1377 	if ((fd = accept(sock, saddr, &len)) == -1) {
1378 		if (errno == EWOULDBLOCK || errno == EAGAIN ||
1379 		    errno == ECONNABORTED)
1380 			return;
1381 		fatal("accept: %s", strerror(errno));
1382 	}
1383 
1384 	mark_nonblock(fd);
1385 
1386 	c = xcalloc(1, sizeof(*c));
1387 	c->id = ++server_client_id;
1388 	c->fd = fd;
1389 	c->pfd = -1;
1390 	c->addr = addr;
1391 
1392 	if (tls_accept_socket(ctx, &c->ctx, fd) == -1) {
1393 		log_warn(c, "failed to accept socket: %s", tls_error(c->ctx));
1394 		close(c->fd);
1395 		free(c);
1396 		return;
1397 	}
1398 
1399 	SPLAY_INSERT(client_tree_id, &clients, c);
1400 	event_once(c->fd, EV_READ|EV_WRITE, handle_handshake, c, NULL);
1401 	connected_clients++;
1402 }
1403 
1404 static struct client *
1405 client_by_id(int id)
1406 {
1407 	struct client *c;
1408 
1409 	if ((c = try_client_by_id(id)) == NULL)
1410 		fatal("in client_by_id: invalid id %d", id);
1411 	return c;
1412 }
1413 
1414 struct client *
1415 try_client_by_id(int id)
1416 {
1417 	struct client find;
1418 
1419 	find.id = id;
1420 	return SPLAY_FIND(client_tree_id, &clients, &find);
1421 }
1422 
1423 static void
1424 handle_imsg_cgi_res(struct imsgbuf *ibuf, struct imsg *imsg, size_t len)
1425 {
1426 	struct client *c;
1427 
1428 	c = client_by_id(imsg->hdr.peerid);
1429 
1430 	if ((c->pfd = imsg->fd) == -1) {
1431 		start_reply(c, TEMP_FAILURE, "internal server error");
1432 		return;
1433 	}
1434 
1435 	c->type = REQUEST_CGI;
1436 
1437 	c->cgibev = bufferevent_new(c->pfd, cgi_read, cgi_write,
1438 	    cgi_error, c);
1439 
1440 	bufferevent_enable(c->cgibev, EV_READ);
1441 }
1442 
1443 static void
1444 handle_imsg_fcgi_fd(struct imsgbuf *ibuf, struct imsg *imsg, size_t len)
1445 {
1446 	struct client	*c;
1447 	int		 id;
1448 
1449 	id = imsg->hdr.peerid;
1450 
1451 	if ((c = try_client_by_id(id)) == NULL) {
1452 		if (imsg->fd != -1)
1453 			close(imsg->fd);
1454 		return;
1455 	}
1456 
1457 	if ((c->pfd = imsg->fd) == -1) {
1458 		start_reply(c, CGI_ERROR, "CGI error");
1459 		return;
1460 	}
1461 
1462 	mark_nonblock(c->pfd);
1463 
1464 	c->cgibev = bufferevent_new(c->pfd, fcgi_read, fcgi_write,
1465 	    fcgi_error, c);
1466 	if (c->cgibev == NULL) {
1467 		start_reply(c, TEMP_FAILURE, "internal server error");
1468 		return;
1469 	}
1470 
1471 	bufferevent_enable(c->cgibev, EV_READ|EV_WRITE);
1472 	fcgi_req(c);
1473 }
1474 
1475 static void
1476 handle_imsg_conn_fd(struct imsgbuf *ibuf, struct imsg *imsg, size_t len)
1477 {
1478 	struct client	*c;
1479 	int		 id;
1480 
1481 	id = imsg->hdr.peerid;
1482 	if ((c = try_client_by_id(id)) == NULL) {
1483 		if (imsg->fd != -1)
1484 			close(imsg->fd);
1485 		return;
1486 	}
1487 
1488 	if ((c->pfd = imsg->fd) == -1) {
1489 		start_reply(c, PROXY_ERROR, "proxy error");
1490 		return;
1491 	}
1492 
1493 	mark_nonblock(c->pfd);
1494 
1495 	if (proxy_init(c) == -1)
1496 		start_reply(c, PROXY_ERROR, "proxy error");
1497 }
1498 
1499 static void
1500 handle_imsg_quit(struct imsgbuf *ibuf, struct imsg *imsg, size_t len)
1501 {
1502 	/*
1503 	 * don't call event_loopbreak since we want to finish to
1504 	 * handle the ongoing connections.
1505 	 */
1506 
1507 	shutting_down = 1;
1508 
1509 	event_del(&e4);
1510 	if (has_ipv6)
1511 		event_del(&e6);
1512 	if (has_siginfo)
1513 		signal_del(&siginfo);
1514 	event_del(&imsgev);
1515 	signal_del(&sigusr2);
1516 }
1517 
1518 static void
1519 handle_dispatch_imsg(int fd, short ev, void *d)
1520 {
1521 	struct imsgbuf *ibuf = d;
1522 	dispatch_imsg(ibuf, handlers, sizeof(handlers));
1523 }
1524 
1525 static void
1526 handle_siginfo(int fd, short ev, void *d)
1527 {
1528 	log_info(NULL, "%d connected clients", connected_clients);
1529 }
1530 
1531 void
1532 loop(struct tls *ctx_, int sock4, int sock6, struct imsgbuf *ibuf)
1533 {
1534 	ctx = ctx_;
1535 
1536 	SPLAY_INIT(&clients);
1537 
1538 	event_init();
1539 
1540 	event_set(&e4, sock4, EV_READ | EV_PERSIST, &do_accept, NULL);
1541 	event_add(&e4, NULL);
1542 
1543 	if (sock6 != -1) {
1544 		has_ipv6 = 1;
1545 		event_set(&e6, sock6, EV_READ | EV_PERSIST, &do_accept, NULL);
1546 		event_add(&e6, NULL);
1547 	}
1548 
1549 	event_set(&imsgev, ibuf->fd, EV_READ | EV_PERSIST, handle_dispatch_imsg, ibuf);
1550 	event_add(&imsgev, NULL);
1551 
1552 #ifdef SIGINFO
1553 	has_siginfo = 1;
1554 	signal_set(&siginfo, SIGINFO, &handle_siginfo, NULL);
1555 	signal_add(&siginfo, NULL);
1556 #endif
1557 	signal_set(&sigusr2, SIGUSR2, &handle_siginfo, NULL);
1558 	signal_add(&sigusr2, NULL);
1559 
1560 	sandbox_server_process();
1561 	event_dispatch();
1562 	_exit(0);
1563 }
1564 
1565 int
1566 client_tree_cmp(struct client *a, struct client *b)
1567 {
1568 	if (a->id == b->id)
1569 		return 0;
1570 	else if (a->id < b->id)
1571 		return -1;
1572 	else
1573 		return +1;
1574 }
1575 
1576 SPLAY_GENERATE(client_tree_id, client, entry, client_tree_cmp)