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Date:: Sat Sep 10 13:18:24 2022 UTC
Message:: server: inline dispatch_imsg
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1 /*
2  * Copyright (c) 2021, 2022 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 #include <sys/un.h>
21 
22 #include <assert.h>
23 #include <ctype.h>
24 #include <errno.h>
25 #include <event.h>
26 #include <fcntl.h>
27 #include <fnmatch.h>
28 #include <limits.h>
29 #include <string.h>
30 
31 #define MIN(a, b)	((a) < (b) ? (a) : (b))
32 
33 int shutting_down;
34 
35 static struct tls	*ctx;
36 
37 static struct event e4, e6, imsgev, siginfo, sigusr2;
38 static int has_ipv6, has_siginfo;
39 
40 int connected_clients;
41 
42 static inline int matches(const char*, const char*);
43 
44 static int	 check_path(struct client*, const char*, int*);
45 static void	 open_file(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 void	 open_dir(struct client*);
55 static void	 redirect_canonical_dir(struct client*);
56 
57 static void	 client_tls_readcb(int, short, void *);
58 static void	 client_tls_writecb(int, short, void *);
59 
60 static void	 client_read(struct bufferevent *, void *);
61 void		 client_write(struct bufferevent *, void *);
62 static void	 client_error(struct bufferevent *, short, void *);
63 
64 static void	 client_close_ev(int, short, void *);
65 
66 static void	 do_accept(int, short, void*);
67 
68 static void	 handle_dispatch_imsg(int, short, void *);
69 static void	 handle_siginfo(int, short, void*);
70 
71 static uint32_t server_client_id;
72 
73 struct client_tree_id clients;
74 
75 static inline int
76 matches(const char *pattern, const char *path)
77 {
78 	if (*path == '/')
79 		path++;
80 	return !fnmatch(pattern, path, 0);
81 }
82 
83 const char *
84 vhost_lang(struct vhost *v, const char *path)
85 {
86 	struct location *loc;
87 
88 	if (v == NULL || path == NULL)
89 		return NULL;
90 
91 	loc = TAILQ_FIRST(&v->locations);
92 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
93 		if (loc->lang != NULL) {
94 			if (matches(loc->match, path))
95 				return loc->lang;
96 		}
97 	}
98 
99 	return TAILQ_FIRST(&v->locations)->lang;
100 }
101 
102 const char *
103 vhost_default_mime(struct vhost *v, const char *path)
104 {
105 	struct location *loc;
106 	const char *default_mime = "application/octet-stream";
107 
108 	if (v == NULL || path == NULL)
109 		return default_mime;
110 
111 	loc = TAILQ_FIRST(&v->locations);
112 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
113 		if (loc->default_mime != NULL) {
114 			if (matches(loc->match, path))
115 				return loc->default_mime;
116 		}
117 	}
118 
119 	loc = TAILQ_FIRST(&v->locations);
120 	if (loc->default_mime != NULL)
121 		return loc->default_mime;
122 	return default_mime;
123 }
124 
125 const char *
126 vhost_index(struct vhost *v, const char *path)
127 {
128 	struct location *loc;
129 	const char *index = "index.gmi";
130 
131 	if (v == NULL || path == NULL)
132 		return index;
133 
134 	loc = TAILQ_FIRST(&v->locations);
135 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
136 		if (loc->index != NULL) {
137 			if (matches(loc->match, path))
138 				return loc->index;
139 		}
140 	}
141 
142 	loc = TAILQ_FIRST(&v->locations);
143 	if (loc->index != NULL)
144 		return loc->index;
145 	return index;
146 }
147 
148 int
149 vhost_auto_index(struct vhost *v, const char *path)
150 {
151 	struct location *loc;
152 
153 	if (v == NULL || path == NULL)
154 		return 0;
155 
156 	loc = TAILQ_FIRST(&v->locations);
157 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
158 		if (loc->auto_index != 0) {
159 			if (matches(loc->match, path))
160 				return loc->auto_index == 1;
161 		}
162 	}
163 
164 	loc = TAILQ_FIRST(&v->locations);
165 	return loc->auto_index == 1;
166 }
167 
168 int
169 vhost_block_return(struct vhost *v, const char *path, int *code, const char **fmt)
170 {
171 	struct location *loc;
172 
173 	if (v == NULL || path == NULL)
174 		return 0;
175 
176 	loc = TAILQ_FIRST(&v->locations);
177 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
178 		if (loc->block_code != 0) {
179 			if (matches(loc->match, path)) {
180 				*code = loc->block_code;
181 				*fmt = loc->block_fmt;
182 				return 1;
183 			}
184 		}
185 	}
186 
187 	loc = TAILQ_FIRST(&v->locations);
188 	*code = loc->block_code;
189 	*fmt = loc->block_fmt;
190 	return loc->block_code != 0;
191 }
192 
193 int
194 vhost_fastcgi(struct vhost *v, const char *path)
195 {
196 	struct location *loc;
197 
198 	if (v == NULL || path == NULL)
199 		return -1;
200 
201 	loc = TAILQ_FIRST(&v->locations);
202 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
203 		if (loc->fcgi != -1)
204 			if (matches(loc->match, path))
205 				return loc->fcgi;
206 	}
207 
208 	loc = TAILQ_FIRST(&v->locations);
209 	return loc->fcgi;
210 }
211 
212 int
213 vhost_dirfd(struct vhost *v, const char *path, size_t *retloc)
214 {
215 	struct location *loc;
216 	size_t		 l = 0;
217 
218 	if (v == NULL || path == NULL)
219 		return -1;
220 
221 	loc = TAILQ_FIRST(&v->locations);
222 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
223 		l++;
224 		if (loc->dirfd != -1)
225 			if (matches(loc->match, path)) {
226 				*retloc = l;
227 				return loc->dirfd;
228 			}
229 	}
230 
231 	*retloc = 0;
232 	loc = TAILQ_FIRST(&v->locations);
233 	return loc->dirfd;
234 }
235 
236 int
237 vhost_strip(struct vhost *v, const char *path)
238 {
239 	struct location *loc;
240 
241 	if (v == NULL || path == NULL)
242 		return 0;
243 
244 	loc = TAILQ_FIRST(&v->locations);
245 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
246 		if (loc->strip != 0) {
247 			if (matches(loc->match, path))
248 				return loc->strip;
249 		}
250 	}
251 
252 	loc = TAILQ_FIRST(&v->locations);
253 	return loc->strip;
254 }
255 
256 X509_STORE *
257 vhost_require_ca(struct vhost *v, const char *path)
258 {
259 	struct location *loc;
260 
261 	if (v == NULL || path == NULL)
262 		return NULL;
263 
264 	loc = TAILQ_FIRST(&v->locations);
265 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
266 		if (loc->reqca != NULL) {
267 			if (matches(loc->match, path))
268 				return loc->reqca;
269 		}
270 	}
271 
272 	loc = TAILQ_FIRST(&v->locations);
273 	return loc->reqca;
274 }
275 
276 int
277 vhost_disable_log(struct vhost *v, const char *path)
278 {
279 	struct location *loc;
280 
281 	if (v == NULL || path == NULL)
282 		return 0;
283 
284 	loc = TAILQ_FIRST(&v->locations);
285 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
286 		if (loc->disable_log && matches(loc->match, path))
287 				return 1;
288 	}
289 
290 	loc = TAILQ_FIRST(&v->locations);
291 	return loc->disable_log;
292 }
293 
294 static int
295 check_path(struct client *c, const char *path, int *fd)
296 {
297 	struct stat sb;
298 	const char *p;
299 	int dirfd, strip;
300 
301 	assert(path != NULL);
302 
303 	/*
304 	 * in send_dir we add an initial / (to be redirect-friendly),
305 	 * but here we want to skip it
306 	 */
307 	if (*path == '/')
308 		path++;
309 
310 	strip = vhost_strip(c->host, path);
311 	p = strip_path(path, strip);
312 
313 	if (*p == '/')
314 		p = p+1;
315 	if (*p == '\0')
316 		p = ".";
317 
318 	dirfd = vhost_dirfd(c->host, path, &c->loc);
319 	log_debug(c, "check_path: strip=%d path=%s original=%s",
320 	    strip, p, path);
321 	if (*fd == -1 && (*fd = openat(dirfd, p, O_RDONLY)) == -1) {
322 		if (errno == EACCES)
323 			log_info(c, "can't open %s: %s", p, strerror(errno));
324 		return FILE_MISSING;
325 	}
326 
327 	if (fstat(*fd, &sb) == -1) {
328 		log_notice(c, "failed stat for %s: %s", path, strerror(errno));
329 		return FILE_MISSING;
330 	}
331 
332 	if (S_ISDIR(sb.st_mode))
333 		return FILE_DIRECTORY;
334 
335 	return FILE_EXISTS;
336 }
337 
338 static void
339 open_file(struct client *c)
340 {
341 	switch (check_path(c, c->iri.path, &c->pfd)) {
342 	case FILE_EXISTS:
343 		c->type = REQUEST_FILE;
344 		start_reply(c, SUCCESS, mime(c->host, c->iri.path));
345 		return;
346 
347 	case FILE_DIRECTORY:
348 		open_dir(c);
349 		return;
350 
351 	case FILE_MISSING:
352 		start_reply(c, NOT_FOUND, "not found");
353 		return;
354 
355 	default:
356 		/* unreachable */
357 		abort();
358 	}
359 }
360 
361 void
362 mark_nonblock(int fd)
363 {
364 	int flags;
365 
366 	if ((flags = fcntl(fd, F_GETFL)) == -1)
367 		fatal("fcntl(F_GETFL): %s", strerror(errno));
368 	if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1)
369 		fatal("fcntl(F_SETFL): %s", strerror(errno));
370 }
371 
372 static void
373 handle_handshake(int fd, short ev, void *d)
374 {
375 	struct client *c = d;
376 	struct vhost *h;
377 	struct alist *a;
378 	const char *servname;
379 	const char *parse_err = "unknown error";
380 
381 	switch (tls_handshake(c->ctx)) {
382 	case 0:  /* success */
383 	case -1: /* already handshaked */
384 		break;
385 	case TLS_WANT_POLLIN:
386 		event_once(c->fd, EV_READ, handle_handshake, c, NULL);
387 		return;
388 	case TLS_WANT_POLLOUT:
389 		event_once(c->fd, EV_WRITE, handle_handshake, c, NULL);
390 		return;
391 	default:
392 		/* unreachable */
393 		abort();
394 	}
395 
396 	c->bev = bufferevent_new(fd, client_read, client_write,
397 	    client_error, c);
398 	if (c->bev == NULL)
399 		fatal("%s: failed to allocate client buffer: %s",
400 		    __func__, strerror(errno));
401 
402 	event_set(&c->bev->ev_read, c->fd, EV_READ,
403 	    client_tls_readcb, c->bev);
404 	event_set(&c->bev->ev_write, c->fd, EV_WRITE,
405 	    client_tls_writecb, c->bev);
406 
407 #if HAVE_LIBEVENT2
408 	evbuffer_unfreeze(c->bev->input, 0);
409 	evbuffer_unfreeze(c->bev->output, 1);
410 #endif
411 
412 	if ((servname = tls_conn_servername(c->ctx)) == NULL) {
413 		log_debug(c, "handshake: missing SNI");
414 		goto err;
415 	}
416 
417 	if (!puny_decode(servname, c->domain, sizeof(c->domain), &parse_err)) {
418 		log_info(c, "puny_decode: %s", parse_err);
419 		goto err;
420 	}
421 
422 	TAILQ_FOREACH(h, &hosts, vhosts) {
423 		if (matches(h->domain, c->domain))
424 			goto found;
425 		TAILQ_FOREACH(a, &h->aliases, aliases) {
426 			if (matches(a->alias, c->domain))
427 				goto found;
428 		}
429 	}
430 
431 found:
432 	log_debug(c, "handshake: SNI: \"%s\"; decoded: \"%s\"; matched: \"%s\"",
433 	    servname != NULL ? servname : "(null)",
434 	    c->domain,
435 	    h != NULL ? h->domain : "(null)");
436 
437 	if (h != NULL) {
438 		c->host = h;
439 		bufferevent_enable(c->bev, EV_READ);
440 		return;
441 	}
442 
443 err:
444 	start_reply(c, BAD_REQUEST, "Wrong/malformed host or missing SNI");
445 }
446 
447 static const char *
448 strip_path(const char *path, int strip)
449 {
450 	char *t;
451 
452 	while (strip > 0) {
453 		if ((t = strchr(path, '/')) == NULL) {
454 			path = strchr(path, '\0');
455 			break;
456 		}
457 		path = t;
458 		strip--;
459 	}
460 
461 	return path;
462 }
463 
464 static void
465 fmt_sbuf(const char *fmt, struct client *c, const char *path)
466 {
467 	size_t i;
468 	char buf[32];
469 
470 	memset(buf, 0, sizeof(buf));
471 	for (i = 0; *fmt; ++fmt) {
472 		if (i == sizeof(buf)-1 || *fmt == '%') {
473 			strlcat(c->sbuf, buf, sizeof(c->sbuf));
474 			memset(buf, 0, sizeof(buf));
475 			i = 0;
476 		}
477 
478 		if (*fmt != '%') {
479 			buf[i++] = *fmt;
480 			continue;
481 		}
482 
483 		switch (*++fmt) {
484 		case '%':
485 			strlcat(c->sbuf, "%", sizeof(c->sbuf));
486 			break;
487 		case 'p':
488 			if (*path != '/')
489 				strlcat(c->sbuf, "/", sizeof(c->sbuf));
490 			strlcat(c->sbuf, path, sizeof(c->sbuf));
491 			break;
492 		case 'q':
493 			strlcat(c->sbuf, c->iri.query, sizeof(c->sbuf));
494 			break;
495 		case 'P':
496 			snprintf(buf, sizeof(buf), "%d", conf.port);
497 			strlcat(c->sbuf, buf, sizeof(c->sbuf));
498 			memset(buf, 0, sizeof(buf));
499 			break;
500 		case 'N':
501 			strlcat(c->sbuf, c->domain, sizeof(c->sbuf));
502 			break;
503 		default:
504 			fatal("%s: unknown fmt specifier %c",
505 			    __func__, *fmt);
506 		}
507 	}
508 
509 	if (i != 0)
510 		strlcat(c->sbuf, buf, sizeof(c->sbuf));
511 }
512 
513 /* 1 if a matching `block return' (and apply it), 0 otherwise */
514 static int
515 apply_block_return(struct client *c)
516 {
517 	const char *fmt, *path;
518 	int code;
519 
520 	if (!vhost_block_return(c->host, c->iri.path, &code, &fmt))
521 		return 0;
522 
523 	path = strip_path(c->iri.path, vhost_strip(c->host, c->iri.path));
524 	fmt_sbuf(fmt, c, path);
525 
526 	start_reply(c, code, c->sbuf);
527 	return 1;
528 }
529 
530 static struct proxy *
531 matched_proxy(struct client *c)
532 {
533 	struct proxy	*p;
534 	const char	*proto;
535 	const char	*host;
536 	const char	*port;
537 
538 	TAILQ_FOREACH(p, &c->host->proxies, proxies) {
539 		if ((proto = p->match_proto) == NULL)
540 			proto = "gemini";
541 		if ((host = p->match_host) == NULL)
542 			host = "*";
543 		if ((port = p->match_port) == NULL)
544 			port = "*";
545 
546 		if (matches(proto, c->iri.schema) &&
547 		    matches(host, c->domain) &&
548 		    matches(port, c->iri.port))
549 			return p;
550 	}
551 
552 	return NULL;
553 }
554 
555 static int
556 check_matching_certificate(X509_STORE *store, struct client *c)
557 {
558 	const uint8_t	*cert;
559 	size_t		 len;
560 
561 	if (!tls_peer_cert_provided(c->ctx)) {
562 		start_reply(c, CLIENT_CERT_REQ, "client certificate required");
563 		return 1;
564 	}
565 
566 	cert = tls_peer_cert_chain_pem(c->ctx, &len);
567 	if (!validate_against_ca(store, cert, len)) {
568 		start_reply(c, CERT_NOT_AUTH, "certificate not authorised");
569 		return 1;
570 	}
571 
572 	return 0;
573 }
574 
575 static int
576 proxy_socket(struct client *c, const char *host, const char *port)
577 {
578 	struct addrinfo hints, *res, *res0;
579 	int r, sock;
580 
581 	memset(&hints, 0, sizeof(hints));
582 	hints.ai_family = AF_UNSPEC;
583 	hints.ai_socktype = SOCK_STREAM;
584 
585 	/* XXX: asr_run? :> */
586 	r = getaddrinfo(host, port, &hints, &res0);
587 	if (r != 0) {
588 		log_warn(c, "getaddrinfo(\"%s\", \"%s\"): %s",
589 		    host, port, gai_strerror(r));
590 		return -1;
591 	}
592 
593 	for (res = res0; res; res = res->ai_next) {
594 		sock = socket(res->ai_family, res->ai_socktype,
595 		    res->ai_protocol);
596 		if (sock == -1)
597 			continue;
598 
599 		if (connect(sock, res->ai_addr, res->ai_addrlen) == -1) {
600 			close(sock);
601 			sock = -1;
602 			continue;
603 		}
604 
605 		break;
606 	}
607 
608 	freeaddrinfo(res0);
609 
610 	if (sock == -1)
611 		log_warn(c, "can't connect to %s:%s", host, port);
612 
613 	return sock;
614 }
615 
616 /* 1 if matching a proxy relay-to (and apply it), 0 otherwise */
617 static int
618 apply_reverse_proxy(struct client *c)
619 {
620 	struct proxy	*p;
621 
622 	if ((p = matched_proxy(c)) == NULL)
623 		return 0;
624 
625 	c->proxy = p;
626 
627 	if (p->reqca != NULL && check_matching_certificate(p->reqca, c))
628 		return 1;
629 
630 	log_debug(c, "opening proxy connection for %s:%s",
631 	    p->host, p->port);
632 
633 	if ((c->pfd = proxy_socket(c, p->host, p->port)) == -1) {
634 		start_reply(c, PROXY_ERROR, "proxy error");
635 		return 1;
636 	}
637 
638 	mark_nonblock(c->pfd);
639 	if (proxy_init(c) == -1)
640 		start_reply(c, PROXY_ERROR, "proxy error");
641 
642 	return 1;
643 }
644 
645 static int
646 fcgi_open_sock(struct fcgi *f)
647 {
648 	struct sockaddr_un	addr;
649 	int			fd;
650 
651 	if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
652 		log_err(NULL, "socket: %s", strerror(errno));
653 		return -1;
654 	}
655 
656 	memset(&addr, 0, sizeof(addr));
657 	addr.sun_family = AF_UNIX;
658 	strlcpy(addr.sun_path, f->path, sizeof(addr.sun_path));
659 
660 	if (connect(fd, (struct sockaddr*)&addr, sizeof(addr)) == -1) {
661 		log_warn(NULL, "failed to connect to %s: %s", f->path,
662 		    strerror(errno));
663 		close(fd);
664 		return -1;
665 	}
666 
667 	return fd;
668 }
669 
670 static int
671 fcgi_open_conn(struct fcgi *f)
672 {
673 	struct addrinfo	hints, *servinfo, *p;
674 	int		r, sock;
675 
676 	memset(&hints, 0, sizeof(hints));
677 	hints.ai_family = AF_UNSPEC;
678 	hints.ai_socktype = SOCK_STREAM;
679 	hints.ai_flags = AI_ADDRCONFIG;
680 
681 	if ((r = getaddrinfo(f->path, f->port, &hints, &servinfo)) != 0) {
682 		log_warn(NULL, "getaddrinfo %s:%s: %s", f->path, f->port,
683 		    gai_strerror(r));
684 		return -1;
685 	}
686 
687 	for (p = servinfo; p != NULL; p = p->ai_next) {
688 		sock = socket(p->ai_family, p->ai_socktype, p->ai_protocol);
689 		if (sock == -1)
690 			continue;
691 		if (connect(sock, p->ai_addr, p->ai_addrlen) == -1) {
692 			close(sock);
693 			continue;
694 		}
695 		break;
696 	}
697 
698 	if (p == NULL) {
699 		log_warn(NULL, "couldn't connect to %s:%s", f->path, f->port);
700 		sock = -1;
701 	}
702 
703 	freeaddrinfo(servinfo);
704 	return sock;
705 }
706 
707 /* 1 if matching `fcgi' (and apply it), 0 otherwise */
708 static int
709 apply_fastcgi(struct client *c)
710 {
711 	int		 id;
712 	struct fcgi	*f;
713 
714 	if ((id = vhost_fastcgi(c->host, c->iri.path)) == -1)
715 		return 0;
716 
717 	f = &fcgi[id];
718 
719 	log_debug(c, "opening fastcgi connection for (%s,%s)",
720 	    f->path, f->port);
721 
722 	if (f->port != NULL)
723 		c->pfd = fcgi_open_sock(f);
724 	else
725 		c->pfd = fcgi_open_conn(f);
726 
727 	if (c->pfd == -1) {
728 		start_reply(c, CGI_ERROR, "CGI error");
729 		return 1;
730 	}
731 
732 	mark_nonblock(c->pfd);
733 
734 	c->cgibev = bufferevent_new(c->pfd, fcgi_read, fcgi_write,
735 	    fcgi_error, c);
736 	if (c->cgibev == NULL) {
737 		start_reply(c, TEMP_FAILURE, "internal server error");
738 		return 1;
739 	}
740 
741 	bufferevent_enable(c->cgibev, EV_READ|EV_WRITE);
742 	fcgi_req(c);
743 
744 	return 1;
745 }
746 
747 /* 1 if matching `require client ca' fails (and apply it), 0 otherwise */
748 static int
749 apply_require_ca(struct client *c)
750 {
751 	X509_STORE	*store;
752 
753 	if ((store = vhost_require_ca(c->host, c->iri.path)) == NULL)
754 		return 0;
755 	return check_matching_certificate(store, c);
756 }
757 
758 static void
759 open_dir(struct client *c)
760 {
761 	size_t len;
762 	int dirfd, root;
763 	char *before_file;
764 
765 	log_debug(c, "in open_dir");
766 
767 	root = !strcmp(c->iri.path, "/") || *c->iri.path == '\0';
768 
769 	len = strlen(c->iri.path);
770 	if (len > 0 && !ends_with(c->iri.path, "/")) {
771 		redirect_canonical_dir(c);
772 		return;
773 	}
774 
775 	strlcpy(c->sbuf, "/", sizeof(c->sbuf));
776 	strlcat(c->sbuf, c->iri.path, sizeof(c->sbuf));
777 	if (!ends_with(c->sbuf, "/"))
778 		strlcat(c->sbuf, "/", sizeof(c->sbuf));
779 	before_file = strchr(c->sbuf, '\0');
780 	len = strlcat(c->sbuf, vhost_index(c->host, c->iri.path),
781 	    sizeof(c->sbuf));
782 	if (len >= sizeof(c->sbuf)) {
783 		start_reply(c, TEMP_FAILURE, "internal server error");
784 		return;
785 	}
786 
787 	c->iri.path = c->sbuf;
788 
789 	/* close later unless we have to generate the dir listing */
790 	dirfd = c->pfd;
791 	c->pfd = -1;
792 
793 	switch (check_path(c, c->iri.path, &c->pfd)) {
794 	case FILE_EXISTS:
795 		c->type = REQUEST_FILE;
796 		start_reply(c, SUCCESS, mime(c->host, c->iri.path));
797 		break;
798 
799 	case FILE_DIRECTORY:
800 		start_reply(c, TEMP_REDIRECT, c->sbuf);
801 		break;
802 
803 	case FILE_MISSING:
804 		*before_file = '\0';
805 
806 		if (!vhost_auto_index(c->host, c->iri.path)) {
807 			start_reply(c, NOT_FOUND, "not found");
808 			break;
809 		}
810 
811 		c->type = REQUEST_DIR;
812 
813 		c->dirlen = scandir_fd(dirfd, &c->dir,
814 		    root ? select_non_dotdot : select_non_dot,
815 		    alphasort);
816 		if (c->dirlen == -1) {
817 			log_err(c, "scandir_fd(%d) (vhost:%s) %s: %s",
818 			    c->pfd, c->host->domain, c->iri.path, strerror(errno));
819 			start_reply(c, TEMP_FAILURE, "internal server error");
820 			return;
821 		}
822 		c->diroff = 0;
823 		c->off = 0;
824 
825 		start_reply(c, SUCCESS, "text/gemini");
826 		evbuffer_add_printf(EVBUFFER_OUTPUT(c->bev),
827 		    "# Index of %s\n\n", c->iri.path);
828 		return;
829 
830 	default:
831 		/* unreachable */
832 		abort();
833 	}
834 
835 	close(dirfd);
836 }
837 
838 static void
839 redirect_canonical_dir(struct client *c)
840 {
841 	size_t len;
842 
843 	strlcpy(c->sbuf, "/", sizeof(c->sbuf));
844 	strlcat(c->sbuf, c->iri.path, sizeof(c->sbuf));
845 	len = strlcat(c->sbuf, "/", sizeof(c->sbuf));
846 
847 	if (len >= sizeof(c->sbuf)) {
848 		start_reply(c, TEMP_FAILURE, "internal server error");
849 		return;
850 	}
851 
852 	start_reply(c, TEMP_REDIRECT, c->sbuf);
853 }
854 
855 static void
856 client_tls_readcb(int fd, short event, void *d)
857 {
858 	struct bufferevent	*bufev = d;
859 	struct client		*client = bufev->cbarg;
860 	ssize_t			 ret;
861 	size_t			 len;
862 	int			 what = EVBUFFER_READ;
863 	int			 howmuch = IBUF_READ_SIZE;
864 	char			 buf[IBUF_READ_SIZE];
865 
866 	if (event == EV_TIMEOUT) {
867 		what |= EVBUFFER_TIMEOUT;
868 		goto err;
869 	}
870 
871 	if (bufev->wm_read.high != 0)
872 		howmuch = MIN(sizeof(buf), bufev->wm_read.high);
873 
874 	switch (ret = tls_read(client->ctx, buf, howmuch)) {
875 	case TLS_WANT_POLLIN:
876 	case TLS_WANT_POLLOUT:
877 		goto retry;
878 	case -1:
879 		what |= EVBUFFER_ERROR;
880 		goto err;
881 	}
882 	len = ret;
883 
884 	if (len == 0) {
885 		what |= EVBUFFER_EOF;
886 		goto err;
887 	}
888 
889 	if (evbuffer_add(bufev->input, buf, len) == -1) {
890 		what |= EVBUFFER_ERROR;
891 		goto err;
892 	}
893 
894 	event_add(&bufev->ev_read, NULL);
895 	if (bufev->wm_read.low != 0 && len < bufev->wm_read.low)
896 		return;
897 	if (bufev->wm_read.high != 0 && len > bufev->wm_read.high) {
898 		/*
899 		 * here we could implement a read pressure policy.
900 		 */
901 	}
902 
903 	if (bufev->readcb != NULL)
904 		(*bufev->readcb)(bufev, bufev->cbarg);
905 
906 	return;
907 
908 retry:
909 	event_add(&bufev->ev_read, NULL);
910 	return;
911 
912 err:
913 	(*bufev->errorcb)(bufev, what, bufev->cbarg);
914 }
915 
916 static void
917 client_tls_writecb(int fd, short event, void *d)
918 {
919 	struct bufferevent	*bufev = d;
920 	struct client		*client = bufev->cbarg;
921 	ssize_t			 ret;
922 	size_t			 len;
923 	short			 what = EVBUFFER_WRITE;
924 
925 	if (event == EV_TIMEOUT) {
926 		what |= EVBUFFER_TIMEOUT;
927 		goto err;
928 	}
929 
930 	if (EVBUFFER_LENGTH(bufev->output) != 0) {
931 		ret = tls_write(client->ctx,
932 		    EVBUFFER_DATA(bufev->output),
933 		    EVBUFFER_LENGTH(bufev->output));
934 		switch (ret) {
935 		case TLS_WANT_POLLIN:
936 		case TLS_WANT_POLLOUT:
937 			goto retry;
938 		case -1:
939 			what |= EVBUFFER_ERROR;
940 			goto err;
941 		}
942 		len = ret;
943 		evbuffer_drain(bufev->output, len);
944 	}
945 
946 	if (EVBUFFER_LENGTH(bufev->output) != 0)
947 		event_add(&bufev->ev_write, NULL);
948 
949 	if (bufev->writecb != NULL &&
950 	    EVBUFFER_LENGTH(bufev->output) <= bufev->wm_write.low)
951 		(*bufev->writecb)(bufev, bufev->cbarg);
952 	return;
953 
954 retry:
955 	event_add(&bufev->ev_write, NULL);
956 	return;
957 err:
958 	log_err(client, "tls error: %s", tls_error(client->ctx));
959 	(*bufev->errorcb)(bufev, what, bufev->cbarg);
960 }
961 
962 static void
963 client_read(struct bufferevent *bev, void *d)
964 {
965 	struct client	*c = d;
966 	struct evbuffer	*src = EVBUFFER_INPUT(bev);
967 	const char	*parse_err = "invalid request";
968 	char		 decoded[DOMAIN_NAME_LEN];
969 	size_t		 len;
970 
971 	bufferevent_disable(bev, EVBUFFER_READ);
972 
973 	/*
974 	 * libevent2 can still somehow call this function, even
975 	 * though I never enable EV_READ in the bufferevent.  If
976 	 * that's the case, bail out.
977 	 */
978 	if (c->type != REQUEST_UNDECIDED)
979 		return;
980 
981 	/* max url len + \r\n */
982 	if (EVBUFFER_LENGTH(src) > 1024 + 2) {
983 		log_err(c, "too much data received");
984 		start_reply(c, BAD_REQUEST, "bad request");
985 		return;
986 	}
987 
988 	c->req = evbuffer_readln(src, &len, EVBUFFER_EOL_CRLF_STRICT);
989 	if (c->req == NULL) {
990 		/* not enough data yet. */
991 		bufferevent_enable(bev, EVBUFFER_READ);
992 		return;
993 	}
994 	c->reqlen = strlen(c->req);
995 	if (c->reqlen > 1024+2) {
996 		log_err(c, "URL too long");
997 		start_reply(c, BAD_REQUEST, "bad request");
998 		return;
999 	}
1000 
1001 	if (!parse_iri(c->req, &c->iri, &parse_err) ||
1002 	    !puny_decode(c->iri.host, decoded, sizeof(decoded), &parse_err)) {
1003 		log_err(c, "IRI parse error: %s", parse_err);
1004 		start_reply(c, BAD_REQUEST, "bad request");
1005 		return;
1006 	}
1007 
1008 	if (apply_reverse_proxy(c))
1009 		return;
1010 
1011 	/* ignore the port number */
1012 	if (strcmp(c->iri.schema, "gemini") ||
1013 	    strcmp(decoded, c->domain)) {
1014 		start_reply(c, PROXY_REFUSED, "won't proxy request");
1015 		return;
1016 	}
1017 
1018 	if (apply_require_ca(c) ||
1019 	    apply_block_return(c)||
1020 	    apply_fastcgi(c))
1021 		return;
1022 
1023 	open_file(c);
1024 }
1025 
1026 void
1027 client_write(struct bufferevent *bev, void *d)
1028 {
1029 	struct client	*c = d;
1030 	struct evbuffer	*out = EVBUFFER_OUTPUT(bev);
1031 	char		 nam[PATH_MAX];
1032 	char		 buf[BUFSIZ];
1033 	ssize_t		 r;
1034 
1035 	switch (c->type) {
1036 	case REQUEST_UNDECIDED:
1037 		/*
1038 		 * Ignore spurious calls when we still don't have idea
1039 		 * what to do with the request.
1040 		 */
1041 		break;
1042 
1043 	case REQUEST_FILE:
1044 		if ((r = read(c->pfd, buf, sizeof(buf))) == -1) {
1045 			log_warn(c, "read: %s", strerror(errno));
1046 			client_error(bev, EVBUFFER_ERROR, c);
1047 			return;
1048 		} else if (r == 0) {
1049 			client_close(c);
1050 			return;
1051 		} else if (r != sizeof(buf))
1052 			c->type = REQUEST_DONE;
1053 		bufferevent_write(bev, buf, r);
1054 		break;
1055 
1056 	case REQUEST_DIR:
1057 		/* TODO: handle big big directories better */
1058 		for (c->diroff = 0; c->diroff < c->dirlen; ++c->diroff) {
1059 			const char *sufx = "";
1060 
1061 			encode_path(nam, sizeof(nam),
1062 			    c->dir[c->diroff]->d_name);
1063 			if (c->dir[c->diroff]->d_type == DT_DIR)
1064 				sufx = "/";
1065 			evbuffer_add_printf(out, "=> ./%s%s\n", nam, sufx);
1066 			free(c->dir[c->diroff]);
1067 		}
1068 		free(c->dir);
1069 		c->dir = NULL;
1070 
1071 		c->type = REQUEST_DONE;
1072 
1073 		event_add(&c->bev->ev_write, NULL);
1074 		break;
1075 
1076 	case REQUEST_FCGI:
1077 	case REQUEST_PROXY:
1078 		/*
1079 		 * Here we depend on fastcgi or proxy connection to
1080 		 * provide data.
1081 		 */
1082 		break;
1083 
1084 	case REQUEST_DONE:
1085 		if (EVBUFFER_LENGTH(out) == 0)
1086 			client_close(c);
1087 		break;
1088 	}
1089 }
1090 
1091 static void
1092 client_error(struct bufferevent *bev, short error, void *d)
1093 {
1094 	struct client	*c = d;
1095 
1096 	c->type = REQUEST_DONE;
1097 
1098 	if (error & EVBUFFER_TIMEOUT) {
1099 		log_warn(c, "timeout reached, "
1100 		    "forcefully closing the connection");
1101 		if (c->code == 0)
1102 			start_reply(c, BAD_REQUEST, "timeout");
1103 		else
1104 			client_close(c);
1105 		return;
1106 	}
1107 
1108 	if (error & EVBUFFER_EOF) {
1109 		client_close(c);
1110 		return;
1111 	}
1112 
1113 	log_err(c, "unknown bufferevent error %x", error);
1114 	client_close(c);
1115 }
1116 
1117 void
1118 start_reply(struct client *c, int code, const char *meta)
1119 {
1120 	struct evbuffer	*evb = EVBUFFER_OUTPUT(c->bev);
1121 	const char	*lang;
1122 	int		 r, rr;
1123 
1124 	bufferevent_enable(c->bev, EVBUFFER_WRITE);
1125 
1126 	c->code = code;
1127 	c->meta = meta;
1128 
1129 	r = evbuffer_add_printf(evb, "%d %s", code, meta);
1130 	if (r == -1)
1131 		goto err;
1132 
1133 	/* 2 digit status + space + 1024 max reply */
1134 	if (r > 1027)
1135 		goto overflow;
1136 
1137 	if (c->type != REQUEST_FCGI &&
1138 	    c->type != REQUEST_PROXY &&
1139 	    !strcmp(meta, "text/gemini") &&
1140 	    (lang = vhost_lang(c->host, c->iri.path)) != NULL) {
1141 		rr = evbuffer_add_printf(evb, ";lang=%s", lang);
1142 		if (rr == -1)
1143 			goto err;
1144 		if (r + rr > 1027)
1145 			goto overflow;
1146 	}
1147 
1148 	bufferevent_write(c->bev, "\r\n", 2);
1149 
1150 	if (!vhost_disable_log(c->host, c->iri.path))
1151 		log_request(c, EVBUFFER_DATA(evb), EVBUFFER_LENGTH(evb));
1152 
1153 	if (code != 20)
1154 		c->type = REQUEST_DONE;
1155 
1156 	return;
1157 
1158 err:
1159 	log_err(c, "evbuffer_add_printf error: no memory");
1160 	evbuffer_drain(evb, EVBUFFER_LENGTH(evb));
1161 	client_close(c);
1162 	return;
1163 
1164 overflow:
1165 	log_warn(c, "reply header overflow");
1166 	evbuffer_drain(evb, EVBUFFER_LENGTH(evb));
1167 	start_reply(c, TEMP_FAILURE, "internal error");
1168 }
1169 
1170 static void
1171 client_close_ev(int fd, short event, void *d)
1172 {
1173 	struct client	*c = d;
1174 
1175 	switch (tls_close(c->ctx)) {
1176 	case TLS_WANT_POLLIN:
1177 		event_once(c->fd, EV_READ, client_close_ev, c, NULL);
1178 		break;
1179 	case TLS_WANT_POLLOUT:
1180 		event_once(c->fd, EV_WRITE, client_close_ev, c, NULL);
1181 		break;
1182 	}
1183 
1184 	connected_clients--;
1185 
1186 	free(c->req);
1187 
1188 	tls_free(c->ctx);
1189 	c->ctx = NULL;
1190 
1191 	free(c->header);
1192 
1193 	if (c->pfd != -1)
1194 		close(c->pfd);
1195 
1196 	if (c->dir != NULL)
1197 		free(c->dir);
1198 
1199 	close(c->fd);
1200 	c->fd = -1;
1201 }
1202 
1203 static void
1204 client_proxy_close(int fd, short event, void *d)
1205 {
1206 	struct tls *ctx = d;
1207 
1208 	if (ctx == NULL) {
1209 		close(fd);
1210 		return;
1211 	}
1212 
1213 	switch (tls_close(ctx)) {
1214 	case TLS_WANT_POLLIN:
1215 		event_once(fd, EV_READ, client_proxy_close, d, NULL);
1216 		break;
1217 	case TLS_WANT_POLLOUT:
1218 		event_once(fd, EV_WRITE, client_proxy_close, d, NULL);
1219 		break;
1220 	}
1221 
1222 	tls_free(ctx);
1223 	close(fd);
1224 }
1225 
1226 void
1227 client_close(struct client *c)
1228 {
1229 	/*
1230 	 * We may end up calling client_close in various situations
1231 	 * and for the most unexpected reasons.  Therefore, we need to
1232 	 * ensure that everything gets properly released once we reach
1233 	 * this point.
1234 	 */
1235 
1236 	SPLAY_REMOVE(client_tree_id, &clients, c);
1237 
1238 	if (c->cgibev != NULL) {
1239 		bufferevent_disable(c->cgibev, EVBUFFER_READ|EVBUFFER_WRITE);
1240 		bufferevent_free(c->cgibev);
1241 		c->cgibev = NULL;
1242 		close(c->pfd);
1243 		c->pfd = -1;
1244 	}
1245 
1246 	bufferevent_disable(c->bev, EVBUFFER_READ|EVBUFFER_WRITE);
1247 	bufferevent_free(c->bev);
1248 	c->bev = NULL;
1249 
1250 	if (c->proxyevset &&
1251 	    event_pending(&c->proxyev, EV_READ|EV_WRITE, NULL)) {
1252 		c->proxyevset = 0;
1253 		event_del(&c->proxyev);
1254 	}
1255 
1256 	if (c->pfd != -1 && c->proxyctx != NULL) {
1257 		/* shut down the proxy TLS connection */
1258 		client_proxy_close(c->pfd, 0, c->proxyctx);
1259 		c->pfd = -1;
1260 	}
1261 
1262 	if (c->proxybev != NULL)
1263 		bufferevent_free(c->proxybev);
1264 
1265 	client_close_ev(c->fd, 0, c);
1266 }
1267 
1268 static void
1269 do_accept(int sock, short et, void *d)
1270 {
1271 	struct client *c;
1272 	struct sockaddr_storage addr;
1273 	struct sockaddr *saddr;
1274 	socklen_t len;
1275 	int fd;
1276 
1277 	saddr = (struct sockaddr*)&addr;
1278 	len = sizeof(addr);
1279 	if ((fd = accept(sock, saddr, &len)) == -1) {
1280 		if (errno == EWOULDBLOCK || errno == EAGAIN ||
1281 		    errno == ECONNABORTED)
1282 			return;
1283 		fatal("accept: %s", strerror(errno));
1284 	}
1285 
1286 	mark_nonblock(fd);
1287 
1288 	c = xcalloc(1, sizeof(*c));
1289 	c->id = ++server_client_id;
1290 	c->fd = fd;
1291 	c->pfd = -1;
1292 	c->addr = addr;
1293 
1294 	if (tls_accept_socket(ctx, &c->ctx, fd) == -1) {
1295 		log_warn(c, "failed to accept socket: %s", tls_error(c->ctx));
1296 		close(c->fd);
1297 		free(c);
1298 		return;
1299 	}
1300 
1301 	SPLAY_INSERT(client_tree_id, &clients, c);
1302 	event_once(c->fd, EV_READ|EV_WRITE, handle_handshake, c, NULL);
1303 	connected_clients++;
1304 }
1305 
1306 struct client *
1307 client_by_id(int id)
1308 {
1309 	struct client find;
1310 
1311 	find.id = id;
1312 	return SPLAY_FIND(client_tree_id, &clients, &find);
1313 }
1314 
1315 static void
1316 handle_dispatch_imsg(int fd, short ev, void *d)
1317 {
1318 	struct imsgbuf	*ibuf = d;
1319 	struct imsg	 imsg;
1320 	ssize_t		 n;
1321 
1322 	if ((n = imsg_read(ibuf)) == -1) {
1323 		if (errno == EAGAIN || errno == EWOULDBLOCK)
1324 			return;
1325 		fatal("imsg_read");
1326 	}
1327 
1328 	if (n == 0)
1329 		fatal("connection closed.");	/* XXX: fatalx */
1330 
1331 	for (;;) {
1332 		if ((n = imsg_get(ibuf, &imsg)) == -1)
1333 			fatal("imsg_get");
1334 		if (n == 0)
1335 			return;
1336 
1337 		switch (imsg.hdr.type) {
1338 		case IMSG_QUIT:
1339 			/*
1340 			 * Don't call event_loopbreak since we want to
1341 			 * finish handling the ongoing connections.
1342 			 */
1343 			shutting_down = 1;
1344 
1345 			event_del(&e4);
1346 			if (has_ipv6)
1347 				event_del(&e6);
1348 			if (has_siginfo)
1349 				signal_del(&siginfo);
1350 			event_del(&imsgev);
1351 			signal_del(&sigusr2);
1352 			break;
1353 		default:
1354 			/* XXX: fatalx */
1355 			fatal("Unknown message %d", imsg.hdr.type);
1356 		}
1357 		imsg_free(&imsg);
1358 	}
1359 }
1360 
1361 static void
1362 handle_siginfo(int fd, short ev, void *d)
1363 {
1364 	log_info(NULL, "%d connected clients", connected_clients);
1365 }
1366 
1367 void
1368 loop(struct tls *ctx_, int sock4, int sock6, struct imsgbuf *ibuf)
1369 {
1370 	ctx = ctx_;
1371 
1372 	SPLAY_INIT(&clients);
1373 
1374 	event_init();
1375 
1376 	event_set(&e4, sock4, EV_READ | EV_PERSIST, &do_accept, NULL);
1377 	event_add(&e4, NULL);
1378 
1379 	if (sock6 != -1) {
1380 		has_ipv6 = 1;
1381 		event_set(&e6, sock6, EV_READ | EV_PERSIST, &do_accept, NULL);
1382 		event_add(&e6, NULL);
1383 	}
1384 
1385 	if (ibuf) {
1386 		event_set(&imsgev, ibuf->fd, EV_READ | EV_PERSIST,
1387 		    handle_dispatch_imsg, ibuf);
1388 		event_add(&imsgev, NULL);
1389 	}
1390 
1391 #ifdef SIGINFO
1392 	has_siginfo = 1;
1393 	signal_set(&siginfo, SIGINFO, &handle_siginfo, NULL);
1394 	signal_add(&siginfo, NULL);
1395 #endif
1396 	signal_set(&sigusr2, SIGUSR2, &handle_siginfo, NULL);
1397 	signal_add(&sigusr2, NULL);
1398 
1399 	sandbox_server_process(conf.can_open_sockets);
1400 	event_dispatch();
1401 	_exit(0);
1402 }
1403 
1404 int
1405 client_tree_cmp(struct client *a, struct client *b)
1406 {
1407 	if (a->id == b->id)
1408 		return 0;
1409 	else if (a->id < b->id)
1410 		return -1;
1411 	else
1412 		return +1;
1413 }
1414 
1415 SPLAY_GENERATE(client_tree_id, client, entry, client_tree_cmp)