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	 check_matching_certificate(X509_STORE *, struct client *);
51 static int	 apply_reverse_proxy(struct client *);
52 static int	 apply_fastcgi(struct client*);
53 static int	 apply_require_ca(struct client*);
54 static size_t	 host_nth(struct vhost*);
55 static void	 start_cgi(const char*, const char*, struct client*);
56 static void	 open_dir(struct client*);
57 static void	 redirect_canonical_dir(struct client*);
58 
59 static void	 client_tls_readcb(int, short, void *);
60 static void	 client_tls_writecb(int, short, void *);
61 
62 static void	 client_read(struct bufferevent *, void *);
63 void		 client_write(struct bufferevent *, void *);
64 static void	 client_error(struct bufferevent *, short, void *);
65 
66 static void	 client_close_ev(int, short, void *);
67 
68 static void	 cgi_read(struct bufferevent *, void *);
69 static void	 cgi_write(struct bufferevent *, void *);
70 static void	 cgi_error(struct bufferevent *, short, void *);
71 
72 static void	 do_accept(int, short, void*);
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 static int
634 check_matching_certificate(X509_STORE *store, struct client *c)
635 {
636 	const uint8_t	*cert;
637 	size_t		 len;
638 
639 	if (!tls_peer_cert_provided(c->ctx)) {
640 		start_reply(c, CLIENT_CERT_REQ, "client certificate required");
641 		return 1;
642 	}
643 
644 	cert = tls_peer_cert_chain_pem(c->ctx, &len);
645 	if (!validate_against_ca(store, cert, len)) {
646 		start_reply(c, CERT_NOT_AUTH, "certificate not authorised");
647 		return 1;
648 	}
649 
650 	return 0;
651 }
652 
653 /* 1 if matching a proxy relay-to (and apply it), 0 otherwise */
654 static int
655 apply_reverse_proxy(struct client *c)
656 {
657 	struct proxy	*p;
658 	struct connreq	 r;
659 
660 	if ((p = matched_proxy(c)) == NULL)
661 		return 0;
662 
663 	c->proxy = p;
664 
665 	if (p->reqca != NULL && check_matching_certificate(p->reqca, c))
666 		return 1;
667 
668 	log_debug(c, "opening proxy connection for %s:%s",
669 	    p->host, p->port);
670 
671 	strlcpy(r.host, p->host, sizeof(r.host));
672 	strlcpy(r.port, p->port, sizeof(r.port));
673 
674 	imsg_compose(&exibuf, IMSG_CONN_REQ, c->id, 0, -1, &r, sizeof(r));
675 	imsg_flush(&exibuf);
676 
677 	return 1;
678 }
679 
680 /* 1 if matching `fcgi' (and apply it), 0 otherwise */
681 static int
682 apply_fastcgi(struct client *c)
683 {
684 	int		 id;
685 	struct fcgi	*f;
686 
687 	if ((id = vhost_fastcgi(c->host, c->iri.path)) == -1)
688 		return 0;
689 
690 	f = &fcgi[id];
691 
692 	log_debug(c, "opening fastcgi connection for (%s,%s,%s)",
693 	    f->path, f->port, f->prog);
694 
695 	imsg_compose(&exibuf, IMSG_FCGI_REQ, c->id, 0, -1,
696 	    &id, sizeof(id));
697 	imsg_flush(&exibuf);
698 	return 1;
699 }
700 
701 /* 1 if matching `require client ca' fails (and apply it), 0 otherwise */
702 static int
703 apply_require_ca(struct client *c)
704 {
705 	X509_STORE	*store;
706 
707 	if ((store = vhost_require_ca(c->host, c->iri.path)) == NULL)
708 		return 0;
709 	return check_matching_certificate(store, c);
710 }
711 
712 static size_t
713 host_nth(struct vhost *h)
714 {
715 	struct vhost	*v;
716 	size_t		 i = 0;
717 
718 	TAILQ_FOREACH(v, &hosts, vhosts) {
719 		if (v == h)
720 			return i;
721 		i++;
722 	}
723 
724 	abort();
725 }
726 
727 static void
728 start_cgi(const char *spath, const char *relpath, struct client *c)
729 {
730 	char addr[NI_MAXHOST];
731 	const char *t;
732 	struct cgireq req;
733 	int e;
734 
735 	c->type = REQUEST_CGI;
736 
737 	e = getnameinfo((struct sockaddr*)&c->addr, sizeof(c->addr),
738 	    addr, sizeof(addr),
739 	    NULL, 0,
740 	    NI_NUMERICHOST);
741 	if (e != 0)
742 		fatal("getnameinfo failed");
743 
744 	memset(&req, 0, sizeof(req));
745 
746 	memcpy(req.buf, c->req, c->reqlen);
747 
748 	req.iri_schema_off = c->iri.schema - c->req;
749 	req.iri_host_off = c->iri.host - c->req;
750 	req.iri_port_off = c->iri.port - c->req;
751 	req.iri_path_off = c->iri.path - c->req;
752 	req.iri_query_off = c->iri.query - c->req;
753 	req.iri_fragment_off = c->iri.fragment - c->req;
754 
755 	req.iri_portno = c->iri.port_no;
756 
757 	strlcpy(req.spath, spath, sizeof(req.spath));
758 	strlcpy(req.relpath, relpath, sizeof(req.relpath));
759 	strlcpy(req.addr, addr, sizeof(req.addr));
760 
761 	if ((t = tls_peer_cert_subject(c->ctx)) != NULL)
762 		strlcpy(req.subject, t, sizeof(req.subject));
763 	if ((t = tls_peer_cert_issuer(c->ctx)) != NULL)
764 		strlcpy(req.issuer, t, sizeof(req.issuer));
765 	if ((t = tls_peer_cert_hash(c->ctx)) != NULL)
766 		strlcpy(req.hash, t, sizeof(req.hash));
767 	if ((t = tls_conn_version(c->ctx)) != NULL)
768 		strlcpy(req.version, t, sizeof(req.version));
769 	if ((t = tls_conn_cipher(c->ctx)) != NULL)
770 		strlcpy(req.cipher, t, sizeof(req.cipher));
771 
772 	req.cipher_strength = tls_conn_cipher_strength(c->ctx);
773 	req.notbefore = tls_peer_cert_notbefore(c->ctx);
774 	req.notafter = tls_peer_cert_notafter(c->ctx);
775 
776 	req.host_off = host_nth(c->host);
777 	req.loc_off = c->loc;
778 
779 	imsg_compose(&exibuf, IMSG_CGI_REQ, c->id, 0, -1, &req, sizeof(req));
780 	imsg_flush(&exibuf);
781 
782 	close(c->pfd);
783 }
784 
785 static void
786 open_dir(struct client *c)
787 {
788 	size_t len;
789 	int dirfd, root;
790 	char *before_file;
791 
792 	root = !strcmp(c->iri.path, "/") || *c->iri.path == '\0';
793 
794 	len = strlen(c->iri.path);
795 	if (len > 0 && !ends_with(c->iri.path, "/")) {
796 		redirect_canonical_dir(c);
797 		return;
798 	}
799 
800 	strlcpy(c->sbuf, "/", sizeof(c->sbuf));
801 	strlcat(c->sbuf, c->iri.path, sizeof(c->sbuf));
802 	if (!ends_with(c->sbuf, "/"))
803 		strlcat(c->sbuf, "/", sizeof(c->sbuf));
804 	before_file = strchr(c->sbuf, '\0');
805 	len = strlcat(c->sbuf, vhost_index(c->host, c->iri.path),
806 	    sizeof(c->sbuf));
807 	if (len >= sizeof(c->sbuf)) {
808 		start_reply(c, TEMP_FAILURE, "internal server error");
809 		return;
810 	}
811 
812 	c->iri.path = c->sbuf;
813 
814 	/* close later unless we have to generate the dir listing */
815 	dirfd = c->pfd;
816 	c->pfd = -1;
817 
818 	switch (check_path(c, c->iri.path, &c->pfd)) {
819 	case FILE_EXECUTABLE:
820 		if (c->host->cgi != NULL && matches(c->host->cgi, c->iri.path)) {
821 			start_cgi(c->iri.path, "", c);
822 			break;
823 		}
824 
825 		/* fallthrough */
826 
827 	case FILE_EXISTS:
828 		c->type = REQUEST_FILE;
829 		start_reply(c, SUCCESS, mime(c->host, c->iri.path));
830 		break;
831 
832 	case FILE_DIRECTORY:
833 		start_reply(c, TEMP_REDIRECT, c->sbuf);
834 		break;
835 
836 	case FILE_MISSING:
837 		*before_file = '\0';
838 
839 		if (!vhost_auto_index(c->host, c->iri.path)) {
840 			start_reply(c, NOT_FOUND, "not found");
841 			break;
842 		}
843 
844 		c->type = REQUEST_DIR;
845 
846 		c->dirlen = scandir_fd(dirfd, &c->dir,
847 		    root ? select_non_dotdot : select_non_dot,
848 		    alphasort);
849 		if (c->dirlen == -1) {
850 			log_err(c, "scandir_fd(%d) (vhost:%s) %s: %s",
851 			    c->pfd, c->host->domain, c->iri.path, strerror(errno));
852 			start_reply(c, TEMP_FAILURE, "internal server error");
853 			return;
854 		}
855 		c->diroff = 0;
856 		c->off = 0;
857 
858 		start_reply(c, SUCCESS, "text/gemini");
859 		evbuffer_add_printf(EVBUFFER_OUTPUT(c->bev),
860 		    "# Index of %s\n\n", c->iri.path);
861 		return;
862 
863 	default:
864 		/* unreachable */
865 		abort();
866 	}
867 
868 	close(dirfd);
869 }
870 
871 static void
872 redirect_canonical_dir(struct client *c)
873 {
874 	size_t len;
875 
876 	strlcpy(c->sbuf, "/", sizeof(c->sbuf));
877 	strlcat(c->sbuf, c->iri.path, sizeof(c->sbuf));
878 	len = strlcat(c->sbuf, "/", sizeof(c->sbuf));
879 
880 	if (len >= sizeof(c->sbuf)) {
881 		start_reply(c, TEMP_FAILURE, "internal server error");
882 		return;
883 	}
884 
885 	start_reply(c, TEMP_REDIRECT, c->sbuf);
886 }
887 
888 static void
889 client_tls_readcb(int fd, short event, void *d)
890 {
891 	struct bufferevent	*bufev = d;
892 	struct client		*client = bufev->cbarg;
893 	ssize_t			 ret;
894 	size_t			 len;
895 	int			 what = EVBUFFER_READ;
896 	int			 howmuch = IBUF_READ_SIZE;
897 	char			 buf[IBUF_READ_SIZE];
898 
899 	if (event == EV_TIMEOUT) {
900 		what |= EVBUFFER_TIMEOUT;
901 		goto err;
902 	}
903 
904 	if (bufev->wm_read.high != 0)
905 		howmuch = MIN(sizeof(buf), bufev->wm_read.high);
906 
907 	switch (ret = tls_read(client->ctx, buf, howmuch)) {
908 	case TLS_WANT_POLLIN:
909 	case TLS_WANT_POLLOUT:
910 		goto retry;
911 	case -1:
912 		what |= EVBUFFER_ERROR;
913 		goto err;
914 	}
915 	len = ret;
916 
917 	if (len == 0) {
918 		what |= EVBUFFER_EOF;
919 		goto err;
920 	}
921 
922 	if (evbuffer_add(bufev->input, buf, len) == -1) {
923 		what |= EVBUFFER_ERROR;
924 		goto err;
925 	}
926 
927 	event_add(&bufev->ev_read, NULL);
928 	if (bufev->wm_read.low != 0 && len < bufev->wm_read.low)
929 		return;
930 	if (bufev->wm_read.high != 0 && len > bufev->wm_read.high) {
931 		/*
932 		 * here we could implement a read pressure policy.
933 		 */
934 	}
935 
936 	if (bufev->readcb != NULL)
937 		(*bufev->readcb)(bufev, bufev->cbarg);
938 
939 	return;
940 
941 retry:
942 	event_add(&bufev->ev_read, NULL);
943 	return;
944 
945 err:
946 	(*bufev->errorcb)(bufev, what, bufev->cbarg);
947 }
948 
949 static void
950 client_tls_writecb(int fd, short event, void *d)
951 {
952 	struct bufferevent	*bufev = d;
953 	struct client		*client = bufev->cbarg;
954 	ssize_t			 ret;
955 	size_t			 len;
956 	short			 what = EVBUFFER_WRITE;
957 
958 	if (event == EV_TIMEOUT) {
959 		what |= EVBUFFER_TIMEOUT;
960 		goto err;
961 	}
962 
963 	if (EVBUFFER_LENGTH(bufev->output) != 0) {
964 		ret = tls_write(client->ctx,
965 		    EVBUFFER_DATA(bufev->output),
966 		    EVBUFFER_LENGTH(bufev->output));
967 		switch (ret) {
968 		case TLS_WANT_POLLIN:
969 		case TLS_WANT_POLLOUT:
970 			goto retry;
971 		case -1:
972 			what |= EVBUFFER_ERROR;
973 			goto err;
974 		}
975 		len = ret;
976 		evbuffer_drain(bufev->output, len);
977 	}
978 
979 	if (EVBUFFER_LENGTH(bufev->output) != 0)
980 		event_add(&bufev->ev_write, NULL);
981 
982 	if (bufev->writecb != NULL &&
983 	    EVBUFFER_LENGTH(bufev->output) <= bufev->wm_write.low)
984 		(*bufev->writecb)(bufev, bufev->cbarg);
985 	return;
986 
987 retry:
988 	event_add(&bufev->ev_write, NULL);
989 	return;
990 err:
991 	log_err(client, "tls error: %s", tls_error(client->ctx));
992 	(*bufev->errorcb)(bufev, what, bufev->cbarg);
993 }
994 
995 static void
996 client_read(struct bufferevent *bev, void *d)
997 {
998 	struct client	*c = d;
999 	struct evbuffer	*src = EVBUFFER_INPUT(bev);
1000 	const char	*parse_err = "invalid request";
1001 	char		 decoded[DOMAIN_NAME_LEN];
1002 	size_t		 len;
1003 
1004 	bufferevent_disable(bev, EVBUFFER_READ);
1005 
1006 	/*
1007 	 * libevent2 can still somehow call this function, even
1008 	 * though I never enable EV_READ in the bufferevent.  If
1009 	 * that's the case, bail out.
1010 	 */
1011 	if (c->type != REQUEST_UNDECIDED)
1012 		return;
1013 
1014 	/* max url len + \r\n */
1015 	if (EVBUFFER_LENGTH(src) > 1024 + 2) {
1016 		log_err(c, "too much data received");
1017 		start_reply(c, BAD_REQUEST, "bad request");
1018 		return;
1019 	}
1020 
1021 	c->req = evbuffer_readln(src, &len, EVBUFFER_EOL_CRLF_STRICT);
1022 	if (c->req == NULL) {
1023 		/* not enough data yet. */
1024 		bufferevent_enable(bev, EVBUFFER_READ);
1025 		return;
1026 	}
1027 	c->reqlen = strlen(c->req);
1028 	if (c->reqlen > 1024+2) {
1029 		log_err(c, "URL too long");
1030 		start_reply(c, BAD_REQUEST, "bad request");
1031 		return;
1032 	}
1033 
1034 	if (!parse_iri(c->req, &c->iri, &parse_err) ||
1035 	    !puny_decode(c->iri.host, decoded, sizeof(decoded), &parse_err)) {
1036 		log_err(c, "IRI parse error: %s", parse_err);
1037 		start_reply(c, BAD_REQUEST, "bad request");
1038 		return;
1039 	}
1040 
1041 	if (apply_reverse_proxy(c))
1042 		return;
1043 
1044 	/* ignore the port number */
1045 	if (strcmp(c->iri.schema, "gemini") ||
1046 	    strcmp(decoded, c->domain)) {
1047 		start_reply(c, PROXY_REFUSED, "won't proxy request");
1048 		return;
1049 	}
1050 
1051 	if (apply_require_ca(c) ||
1052 	    apply_block_return(c)||
1053 	    apply_fastcgi(c))
1054 		return;
1055 
1056 	if (c->host->entrypoint != NULL) {
1057 		c->loc = 0;
1058 		start_cgi(c->host->entrypoint, c->iri.path, c);
1059 		return;
1060 	}
1061 
1062 	open_file(c);
1063 }
1064 
1065 void
1066 client_write(struct bufferevent *bev, void *d)
1067 {
1068 	struct client	*c = d;
1069 	struct evbuffer	*out = EVBUFFER_OUTPUT(bev);
1070 	char		 buf[BUFSIZ];
1071 	ssize_t		 r;
1072 
1073 	switch (c->type) {
1074 	case REQUEST_UNDECIDED:
1075 		/*
1076 		 * Ignore spurious calls when we still don't have idea
1077 		 * what to do with the request.
1078 		 */
1079 		break;
1080 
1081 	case REQUEST_FILE:
1082 		if ((r = read(c->pfd, buf, sizeof(buf))) == -1) {
1083 			log_warn(c, "read: %s", strerror(errno));
1084 			client_error(bev, EVBUFFER_ERROR, c);
1085 			return;
1086 		} else if (r == 0) {
1087 			client_close(c);
1088 			return;
1089 		} else if (r != sizeof(buf))
1090 			c->type = REQUEST_DONE;
1091 		bufferevent_write(bev, buf, r);
1092 		break;
1093 
1094 	case REQUEST_DIR:
1095 		/* TODO: handle big big directories better */
1096 		for (c->diroff = 0; c->diroff < c->dirlen; ++c->diroff) {
1097 			evbuffer_add_printf(out, "=> %s\n",
1098 			    c->dir[c->diroff]->d_name);
1099 			free(c->dir[c->diroff]);
1100 		}
1101 		free(c->dir);
1102 		c->dir = NULL;
1103 
1104 		c->type = REQUEST_DONE;
1105 
1106 		event_add(&c->bev->ev_write, NULL);
1107 		break;
1108 
1109 	case REQUEST_CGI:
1110 	case REQUEST_FCGI:
1111 	case REQUEST_PROXY:
1112 		/*
1113 		 * Here we depend on the cgi/fastcgi or proxy
1114 		 * connection to provide data.
1115 		 */
1116 		break;
1117 
1118 	case REQUEST_DONE:
1119 		if (EVBUFFER_LENGTH(out) == 0)
1120 			client_close(c);
1121 		break;
1122 	}
1123 }
1124 
1125 static void
1126 client_error(struct bufferevent *bev, short error, void *d)
1127 {
1128 	struct client	*c = d;
1129 
1130 	c->type = REQUEST_DONE;
1131 
1132 	if (error & EVBUFFER_TIMEOUT) {
1133 		log_warn(c, "timeout reached, "
1134 		    "forcefully closing the connection");
1135 		if (c->code == 0)
1136 			start_reply(c, BAD_REQUEST, "timeout");
1137 		else
1138 			client_close(c);
1139 		return;
1140 	}
1141 
1142 	if (error & EVBUFFER_EOF) {
1143 		client_close(c);
1144 		return;
1145 	}
1146 
1147 	log_err(c, "unknown bufferevent error %x", error);
1148 	client_close(c);
1149 }
1150 
1151 void
1152 start_reply(struct client *c, int code, const char *meta)
1153 {
1154 	struct evbuffer	*evb = EVBUFFER_OUTPUT(c->bev);
1155 	const char	*lang;
1156 	int		 r, rr;
1157 
1158 	bufferevent_enable(c->bev, EVBUFFER_WRITE);
1159 
1160 	c->code = code;
1161 	c->meta = meta;
1162 
1163 	r = evbuffer_add_printf(evb, "%d %s", code, meta);
1164 	if (r == -1)
1165 		goto err;
1166 
1167 	/* 2 digit status + space + 1024 max reply */
1168 	if (r > 1027)
1169 		goto overflow;
1170 
1171 	if (c->type != REQUEST_CGI &&
1172 	    c->type != REQUEST_FCGI &&
1173 	    c->type != REQUEST_PROXY &&
1174 	    !strcmp(meta, "text/gemini") &&
1175 	    (lang = vhost_lang(c->host, c->iri.path)) != NULL) {
1176 		rr = evbuffer_add_printf(evb, ";lang=%s", lang);
1177 		if (rr == -1)
1178 			goto err;
1179 		if (r + rr > 1027)
1180 			goto overflow;
1181 	}
1182 
1183 	bufferevent_write(c->bev, "\r\n", 2);
1184 
1185 	if (!vhost_disable_log(c->host, c->iri.path))
1186 		log_request(c, EVBUFFER_DATA(evb), EVBUFFER_LENGTH(evb));
1187 
1188 	if (code != 20)
1189 		c->type = REQUEST_DONE;
1190 
1191 	return;
1192 
1193 err:
1194 	log_err(c, "evbuffer_add_printf error: no memory");
1195 	evbuffer_drain(evb, EVBUFFER_LENGTH(evb));
1196 	client_close(c);
1197 	return;
1198 
1199 overflow:
1200 	log_warn(c, "reply header overflow");
1201 	evbuffer_drain(evb, EVBUFFER_LENGTH(evb));
1202 	start_reply(c, TEMP_FAILURE, "internal error");
1203 }
1204 
1205 static void
1206 client_close_ev(int fd, short event, void *d)
1207 {
1208 	struct client	*c = d;
1209 
1210 	switch (tls_close(c->ctx)) {
1211 	case TLS_WANT_POLLIN:
1212 		event_once(c->fd, EV_READ, client_close_ev, c, NULL);
1213 		break;
1214 	case TLS_WANT_POLLOUT:
1215 		event_once(c->fd, EV_WRITE, client_close_ev, c, NULL);
1216 		break;
1217 	}
1218 
1219 	connected_clients--;
1220 
1221 	free(c->req);
1222 
1223 	tls_free(c->ctx);
1224 	c->ctx = NULL;
1225 
1226 	free(c->header);
1227 
1228 	if (c->pfd != -1)
1229 		close(c->pfd);
1230 
1231 	if (c->dir != NULL)
1232 		free(c->dir);
1233 
1234 	close(c->fd);
1235 	c->fd = -1;
1236 }
1237 
1238 static void
1239 client_proxy_close(int fd, short event, void *d)
1240 {
1241 	struct tls *ctx = d;
1242 
1243 	if (ctx == NULL) {
1244 		close(fd);
1245 		return;
1246 	}
1247 
1248 	switch (tls_close(ctx)) {
1249 	case TLS_WANT_POLLIN:
1250 		event_once(fd, EV_READ, client_proxy_close, d, NULL);
1251 		break;
1252 	case TLS_WANT_POLLOUT:
1253 		event_once(fd, EV_WRITE, client_proxy_close, d, NULL);
1254 		break;
1255 	}
1256 
1257 	tls_free(ctx);
1258 	close(fd);
1259 }
1260 
1261 void
1262 client_close(struct client *c)
1263 {
1264 	/*
1265 	 * We may end up calling client_close in various situations
1266 	 * and for the most unexpected reasons.  Therefore, we need to
1267 	 * ensure that everything gets properly released once we reach
1268 	 * this point.
1269 	 */
1270 
1271 	SPLAY_REMOVE(client_tree_id, &clients, c);
1272 
1273 	if (c->cgibev != NULL) {
1274 		bufferevent_disable(c->cgibev, EVBUFFER_READ|EVBUFFER_WRITE);
1275 		bufferevent_free(c->cgibev);
1276 		c->cgibev = NULL;
1277 		close(c->pfd);
1278 		c->pfd = -1;
1279 	}
1280 
1281 	bufferevent_disable(c->bev, EVBUFFER_READ|EVBUFFER_WRITE);
1282 	bufferevent_free(c->bev);
1283 	c->bev = NULL;
1284 
1285 	if (c->proxyevset &&
1286 	    event_pending(&c->proxyev, EV_READ|EV_WRITE, NULL)) {
1287 		c->proxyevset = 0;
1288 		event_del(&c->proxyev);
1289 	}
1290 
1291 	if (c->pfd != -1 && c->proxyctx != NULL) {
1292 		/* shut down the proxy TLS connection */
1293 		client_proxy_close(c->pfd, 0, c->proxyctx);
1294 		c->pfd = -1;
1295 	}
1296 
1297 	if (c->proxybev != NULL)
1298 		bufferevent_free(c->proxybev);
1299 
1300 	client_close_ev(c->fd, 0, c);
1301 }
1302 
1303 static void
1304 cgi_read(struct bufferevent *bev, void *d)
1305 {
1306 	struct client	*client = d;
1307 	struct evbuffer	*src = EVBUFFER_INPUT(bev);
1308 	char		*header;
1309 	size_t		 len;
1310 	int		 code;
1311 
1312 	/* intercept the header */
1313 	if (client->code == 0) {
1314 		header = evbuffer_readln(src, &len, EVBUFFER_EOL_CRLF_STRICT);
1315 		if (header == NULL) {
1316 			/* max reply + \r\n */
1317 			if (EVBUFFER_LENGTH(src) > 1029) {
1318 				log_warn(client, "CGI script is trying to "
1319 				    "send a header too long.");
1320 				cgi_error(bev, EVBUFFER_READ, client);
1321 			}
1322 
1323 			/* wait a bit */
1324 			return;
1325 		}
1326 
1327 		if (len < 3 || len > 1029 ||
1328 		    !isdigit(header[0]) ||
1329 		    !isdigit(header[1]) ||
1330 		    !isspace(header[2])) {
1331 			free(header);
1332 			log_warn(client, "CGI script is trying to send a "
1333 			    "malformed header");
1334 			cgi_error(bev, EVBUFFER_READ, client);
1335 			return;
1336 		}
1337 
1338 		client->header = header;
1339 		code = (header[0] - '0') * 10 + (header[1] - '0');
1340 
1341 		if (code < 10 || code >= 70) {
1342 			log_warn(client, "CGI script is trying to send an "
1343 			    "invalid reply code (%d)", code);
1344 			cgi_error(bev, EVBUFFER_READ, client);
1345 			return;
1346 		}
1347 
1348 		start_reply(client, code, header + 3);
1349 
1350 		if (client->code < 20 || client->code > 29) {
1351 			cgi_error(client->cgibev, EVBUFFER_EOF, client);
1352 			return;
1353 		}
1354 	}
1355 
1356 	bufferevent_write_buffer(client->bev, src);
1357 }
1358 
1359 static void
1360 cgi_write(struct bufferevent *bev, void *d)
1361 {
1362 	/*
1363 	 * Never called.  We don't send data to a CGI script.
1364 	 */
1365 	abort();
1366 }
1367 
1368 static void
1369 cgi_error(struct bufferevent *bev, short error, void *d)
1370 {
1371 	struct client	*client = d;
1372 
1373 	if (error & EVBUFFER_ERROR)
1374 		log_err(client, "%s: evbuffer error (%x): %s",
1375 		    __func__, error, strerror(errno));
1376 
1377 	bufferevent_disable(bev, EVBUFFER_READ|EVBUFFER_WRITE);
1378 	bufferevent_free(bev);
1379 	client->cgibev = NULL;
1380 
1381 	close(client->pfd);
1382 	client->pfd = -1;
1383 
1384 	client->type = REQUEST_DONE;
1385 	if (client->code != 0)
1386 		client_write(client->bev, client);
1387 	else
1388 		start_reply(client, CGI_ERROR, "CGI error");
1389 }
1390 
1391 static void
1392 do_accept(int sock, short et, void *d)
1393 {
1394 	struct client *c;
1395 	struct sockaddr_storage addr;
1396 	struct sockaddr *saddr;
1397 	socklen_t len;
1398 	int fd;
1399 
1400 	saddr = (struct sockaddr*)&addr;
1401 	len = sizeof(addr);
1402 	if ((fd = accept(sock, saddr, &len)) == -1) {
1403 		if (errno == EWOULDBLOCK || errno == EAGAIN ||
1404 		    errno == ECONNABORTED)
1405 			return;
1406 		fatal("accept: %s", strerror(errno));
1407 	}
1408 
1409 	mark_nonblock(fd);
1410 
1411 	c = xcalloc(1, sizeof(*c));
1412 	c->id = ++server_client_id;
1413 	c->fd = fd;
1414 	c->pfd = -1;
1415 	c->addr = addr;
1416 
1417 	if (tls_accept_socket(ctx, &c->ctx, fd) == -1) {
1418 		log_warn(c, "failed to accept socket: %s", tls_error(c->ctx));
1419 		close(c->fd);
1420 		free(c);
1421 		return;
1422 	}
1423 
1424 	SPLAY_INSERT(client_tree_id, &clients, c);
1425 	event_once(c->fd, EV_READ|EV_WRITE, handle_handshake, c, NULL);
1426 	connected_clients++;
1427 }
1428 
1429 struct client *
1430 client_by_id(int id)
1431 {
1432 	struct client find;
1433 
1434 	find.id = id;
1435 	return SPLAY_FIND(client_tree_id, &clients, &find);
1436 }
1437 
1438 static void
1439 handle_imsg_cgi_res(struct imsgbuf *ibuf, struct imsg *imsg, size_t len)
1440 {
1441 	struct client *c;
1442 
1443 	if ((c = client_by_id(imsg->hdr.peerid)) == NULL) {
1444 		if (imsg->fd != -1)
1445 			close(imsg->fd);
1446 		return;
1447 	}
1448 
1449 	if ((c->pfd = imsg->fd) == -1) {
1450 		start_reply(c, TEMP_FAILURE, "internal server error");
1451 		return;
1452 	}
1453 
1454 	c->type = REQUEST_CGI;
1455 
1456 	c->cgibev = bufferevent_new(c->pfd, cgi_read, cgi_write,
1457 	    cgi_error, c);
1458 
1459 	bufferevent_enable(c->cgibev, EV_READ);
1460 }
1461 
1462 static void
1463 handle_imsg_fcgi_fd(struct imsgbuf *ibuf, struct imsg *imsg, size_t len)
1464 {
1465 	struct client	*c;
1466 	int		 id;
1467 
1468 	id = imsg->hdr.peerid;
1469 
1470 	if ((c = client_by_id(id)) == NULL) {
1471 		if (imsg->fd != -1)
1472 			close(imsg->fd);
1473 		return;
1474 	}
1475 
1476 	if ((c->pfd = imsg->fd) == -1) {
1477 		start_reply(c, CGI_ERROR, "CGI error");
1478 		return;
1479 	}
1480 
1481 	mark_nonblock(c->pfd);
1482 
1483 	c->cgibev = bufferevent_new(c->pfd, fcgi_read, fcgi_write,
1484 	    fcgi_error, c);
1485 	if (c->cgibev == NULL) {
1486 		start_reply(c, TEMP_FAILURE, "internal server error");
1487 		return;
1488 	}
1489 
1490 	bufferevent_enable(c->cgibev, EV_READ|EV_WRITE);
1491 	fcgi_req(c);
1492 }
1493 
1494 static void
1495 handle_imsg_conn_fd(struct imsgbuf *ibuf, struct imsg *imsg, size_t len)
1496 {
1497 	struct client	*c;
1498 	int		 id;
1499 
1500 	id = imsg->hdr.peerid;
1501 	if ((c = client_by_id(id)) == NULL) {
1502 		if (imsg->fd != -1)
1503 			close(imsg->fd);
1504 		return;
1505 	}
1506 
1507 	if ((c->pfd = imsg->fd) == -1) {
1508 		start_reply(c, PROXY_ERROR, "proxy error");
1509 		return;
1510 	}
1511 
1512 	mark_nonblock(c->pfd);
1513 
1514 	if (proxy_init(c) == -1)
1515 		start_reply(c, PROXY_ERROR, "proxy error");
1516 }
1517 
1518 static void
1519 handle_imsg_quit(struct imsgbuf *ibuf, struct imsg *imsg, size_t len)
1520 {
1521 	/*
1522 	 * don't call event_loopbreak since we want to finish to
1523 	 * handle the ongoing connections.
1524 	 */
1525 
1526 	shutting_down = 1;
1527 
1528 	event_del(&e4);
1529 	if (has_ipv6)
1530 		event_del(&e6);
1531 	if (has_siginfo)
1532 		signal_del(&siginfo);
1533 	event_del(&imsgev);
1534 	signal_del(&sigusr2);
1535 }
1536 
1537 static void
1538 handle_dispatch_imsg(int fd, short ev, void *d)
1539 {
1540 	struct imsgbuf *ibuf = d;
1541 	dispatch_imsg(ibuf, handlers, sizeof(handlers));
1542 }
1543 
1544 static void
1545 handle_siginfo(int fd, short ev, void *d)
1546 {
1547 	log_info(NULL, "%d connected clients", connected_clients);
1548 }
1549 
1550 void
1551 loop(struct tls *ctx_, int sock4, int sock6, struct imsgbuf *ibuf)
1552 {
1553 	ctx = ctx_;
1554 
1555 	SPLAY_INIT(&clients);
1556 
1557 	event_init();
1558 
1559 	event_set(&e4, sock4, EV_READ | EV_PERSIST, &do_accept, NULL);
1560 	event_add(&e4, NULL);
1561 
1562 	if (sock6 != -1) {
1563 		has_ipv6 = 1;
1564 		event_set(&e6, sock6, EV_READ | EV_PERSIST, &do_accept, NULL);
1565 		event_add(&e6, NULL);
1566 	}
1567 
1568 	event_set(&imsgev, ibuf->fd, EV_READ | EV_PERSIST, handle_dispatch_imsg, ibuf);
1569 	event_add(&imsgev, NULL);
1570 
1571 #ifdef SIGINFO
1572 	has_siginfo = 1;
1573 	signal_set(&siginfo, SIGINFO, &handle_siginfo, NULL);
1574 	signal_add(&siginfo, NULL);
1575 #endif
1576 	signal_set(&sigusr2, SIGUSR2, &handle_siginfo, NULL);
1577 	signal_add(&sigusr2, NULL);
1578 
1579 	sandbox_server_process();
1580 	event_dispatch();
1581 	_exit(0);
1582 }
1583 
1584 int
1585 client_tree_cmp(struct client *a, struct client *b)
1586 {
1587 	if (a->id == b->id)
1588 		return 0;
1589 	else if (a->id < b->id)
1590 		return -1;
1591 	else
1592 		return +1;
1593 }
1594 
1595 SPLAY_GENERATE(client_tree_id, client, entry, client_tree_cmp)