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 <errno.h>
23 #include <event.h>
24 #include <fcntl.h>
25 #include <fnmatch.h>
26 #include <limits.h>
27 #include <string.h>
28 
29 struct client	 clients[MAX_USERS];
30 
31 static struct tls	*ctx;
32 
33 static struct event e4, e6, imsgev, siginfo, sigusr2;
34 static int has_ipv6, has_siginfo;
35 
36 int connected_clients;
37 
38 static inline int matches(const char*, const char*);
39 
40 static inline void yield_read(int, struct client*, statefn);
41 static inline void yield_write(int, struct client*, statefn);
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 char	*strip_path(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_require_ca(struct client*);
51 static void	 handle_open_conn(int, short, void*);
52 static void	 handle_start_reply(int, short, void*);
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 static void	 enter_handle_dirlist(int, short, void*);
58 static void	 handle_dirlist(int, short, void*);
59 static int 	 read_next_dir_entry(struct client*);
60 static void	 send_directory_listing(int, short, void*);
61 static void	 handle_cgi_reply(int, short, void*);
62 static void	 handle_copy(int, short, void*);
63 static void	 do_accept(int, short, void*);
64 static void	 handle_imsg_cgi_res(struct imsgbuf*, struct imsg*, size_t);
65 static void	 handle_imsg_fcgi_fd(struct imsgbuf*, struct imsg*, size_t);
66 static void	 handle_imsg_quit(struct imsgbuf*, struct imsg*, size_t);
67 static void	 handle_siginfo(int, short, void*);
68 
69 static imsg_handlerfn *handlers[] = {
70 	[IMSG_QUIT] = handle_imsg_quit,
71 	[IMSG_CGI_RES] = handle_imsg_cgi_res,
72 	[IMSG_FCGI_FD] = handle_imsg_fcgi_fd,
73 };
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 static inline void
84 yield_read(int fd, struct client *c, statefn fn)
85 {
86 	event_once(fd, EV_READ, fn, c, NULL);
87 }
88 
89 static inline void
90 yield_write(int fd, struct client *c, statefn fn)
91 {
92 	event_once(fd, EV_WRITE, fn, c, NULL);
93 }
94 
95 const char *
96 vhost_lang(struct vhost *v, const char *path)
97 {
98 	struct location *loc;
99 
100 	if (v == NULL || path == NULL)
101 		return NULL;
102 
103 	loc = TAILQ_FIRST(&v->locations);
104 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
105 		if (loc->lang != NULL) {
106 			if (matches(loc->match, path))
107 				return loc->lang;
108 		}
109 	}
110 
111 	return TAILQ_FIRST(&v->locations)->lang;
112 }
113 
114 const char *
115 vhost_default_mime(struct vhost *v, const char *path)
116 {
117 	struct location *loc;
118 	const char *default_mime = "application/octet-stream";
119 
120 	if (v == NULL || path == NULL)
121 		return default_mime;
122 
123 	loc = TAILQ_FIRST(&v->locations);
124 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
125 		if (loc->default_mime != NULL) {
126 			if (matches(loc->match, path))
127 				return loc->default_mime;
128 		}
129 	}
130 
131 	loc = TAILQ_FIRST(&v->locations);
132 	if (loc->default_mime != NULL)
133 		return loc->default_mime;
134 	return default_mime;
135 }
136 
137 const char *
138 vhost_index(struct vhost *v, const char *path)
139 {
140 	struct location *loc;
141 	const char *index = "index.gmi";
142 
143 	if (v == NULL || path == NULL)
144 		return index;
145 
146 	loc = TAILQ_FIRST(&v->locations);
147 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
148 		if (loc->index != NULL) {
149 			if (matches(loc->match, path))
150 				return loc->index;
151 		}
152 	}
153 
154 	loc = TAILQ_FIRST(&v->locations);
155 	if (loc->index != NULL)
156 		return loc->index;
157 	return index;
158 }
159 
160 int
161 vhost_auto_index(struct vhost *v, const char *path)
162 {
163 	struct location *loc;
164 
165 	if (v == NULL || path == NULL)
166 		return 0;
167 
168 	loc = TAILQ_FIRST(&v->locations);
169 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
170 		if (loc->auto_index != 0) {
171 			if (matches(loc->match, path))
172 				return loc->auto_index == 1;
173 		}
174 	}
175 
176 	loc = TAILQ_FIRST(&v->locations);
177 	return loc->auto_index == 1;
178 }
179 
180 int
181 vhost_block_return(struct vhost *v, const char *path, int *code, const char **fmt)
182 {
183 	struct location *loc;
184 
185 	if (v == NULL || path == NULL)
186 		return 0;
187 
188 	loc = TAILQ_FIRST(&v->locations);
189 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
190 		if (loc->block_code != 0) {
191 			if (matches(loc->match, path)) {
192 				*code = loc->block_code;
193 				*fmt = loc->block_fmt;
194 				return 1;
195 			}
196 		}
197 	}
198 
199 	loc = TAILQ_FIRST(&v->locations);
200 	*code = loc->block_code;
201 	*fmt = loc->block_fmt;
202 	return loc->block_code != 0;
203 }
204 
205 int
206 vhost_fastcgi(struct vhost *v, const char *path)
207 {
208 	struct location *loc;
209 
210 	if (v == NULL || path == NULL)
211 		return -1;
212 
213 	loc = TAILQ_FIRST(&v->locations);
214 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
215 		if (loc->fcgi != -1)
216 			if (matches(loc->match, path))
217 				return loc->fcgi;
218 	}
219 
220 	loc = TAILQ_FIRST(&v->locations);
221 	return loc->fcgi;
222 }
223 
224 int
225 vhost_dirfd(struct vhost *v, const char *path)
226 {
227 	struct location *loc;
228 
229 	if (v == NULL || path == NULL)
230 		return -1;
231 
232 	loc = TAILQ_FIRST(&v->locations);
233 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
234 		if (loc->dirfd != -1)
235 			if (matches(loc->match, path))
236 				return loc->dirfd;
237 	}
238 
239 	loc = TAILQ_FIRST(&v->locations);
240 	return loc->dirfd;
241 }
242 
243 int
244 vhost_strip(struct vhost *v, const char *path)
245 {
246 	struct location *loc;
247 
248 	if (v == NULL || path == NULL)
249 		return 0;
250 
251 	loc = TAILQ_FIRST(&v->locations);
252 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
253 		if (loc->strip != 0) {
254 			if (matches(loc->match, path))
255 				return loc->strip;
256 		}
257 	}
258 
259 	loc = TAILQ_FIRST(&v->locations);
260 	return loc->strip;
261 }
262 
263 X509_STORE *
264 vhost_require_ca(struct vhost *v, const char *path)
265 {
266 	struct location *loc;
267 
268 	if (v == NULL || path == NULL)
269 		return NULL;
270 
271 	loc = TAILQ_FIRST(&v->locations);
272 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
273 		if (loc->reqca != NULL) {
274 			if (matches(loc->match, path))
275 				return loc->reqca;
276 		}
277 	}
278 
279 	loc = TAILQ_FIRST(&v->locations);
280 	return loc->reqca;
281 }
282 
283 int
284 vhost_disable_log(struct vhost *v, const char *path)
285 {
286 	struct location *loc;
287 
288 	if (v == NULL || path == NULL)
289 		return 0;
290 
291 	loc = TAILQ_FIRST(&v->locations);
292 	while ((loc = TAILQ_NEXT(loc, locations)) != NULL) {
293 		if (loc->disable_log && matches(loc->match, path))
294 				return 1;
295 	}
296 
297 	loc = TAILQ_FIRST(&v->locations);
298 	return loc->disable_log;
299 }
300 
301 static int
302 check_path(struct client *c, const char *path, int *fd)
303 {
304 	struct stat sb;
305 	const char *p;
306 	int flags, dirfd, strip;
307 
308 	assert(path != NULL);
309 
310 	/*
311 	 * in send_dir we add an initial / (to be redirect-friendly),
312 	 * but here we want to skip it
313 	 */
314 	if (*path == '/')
315 		path++;
316 
317 	strip = vhost_strip(c->host, path);
318 	p = strip_path(path, strip);
319 
320 	if (*p == '/')
321 		p = p+1;
322 	if (*p == '\0')
323 		p = ".";
324 
325 	dirfd = vhost_dirfd(c->host, path);
326 	log_debug(c, "check_path: strip=%d path=%s original=%s",
327 	    strip, p, path);
328 	flags = O_RDONLY | O_NOFOLLOW;
329 	if (*fd == -1 && (*fd = openat(dirfd, p, flags)) == -1)
330 		return FILE_MISSING;
331 
332 	if (fstat(*fd, &sb) == -1) {
333 		log_notice(c, "failed stat for %s: %s", path, strerror(errno));
334 		return FILE_MISSING;
335 	}
336 
337 	if (S_ISDIR(sb.st_mode))
338 		return FILE_DIRECTORY;
339 
340 	if (sb.st_mode & S_IXUSR)
341 		return FILE_EXECUTABLE;
342 
343 	return FILE_EXISTS;
344 }
345 
346 static void
347 open_file(struct client *c)
348 {
349 	switch (check_path(c, c->iri.path, &c->pfd)) {
350 	case FILE_EXECUTABLE:
351 		if (c->host->cgi != NULL && matches(c->host->cgi, c->iri.path)) {
352 			start_cgi(c->iri.path, "", c);
353 			return;
354 		}
355 
356 		/* fallthrough */
357 
358 	case FILE_EXISTS:
359 		c->next = handle_copy;
360 		start_reply(c, SUCCESS, mime(c->host, c->iri.path));
361 		return;
362 
363 	case FILE_DIRECTORY:
364 		open_dir(c);
365 		return;
366 
367 	case FILE_MISSING:
368 		if (c->host->cgi != NULL && matches(c->host->cgi, c->iri.path)) {
369 			check_for_cgi(c);
370 			return;
371 		}
372 		start_reply(c, NOT_FOUND, "not found");
373 		return;
374 
375 	default:
376 		/* unreachable */
377 		abort();
378 	}
379 }
380 
381 /*
382  * the inverse of this algorithm, i.e. starting from the start of the
383  * path + strlen(cgi), and checking if each component, should be
384  * faster.  But it's tedious to write.  This does the opposite: starts
385  * from the end and strip one component at a time, until either an
386  * executable is found or we emptied the path.
387  */
388 static void
389 check_for_cgi(struct client *c)
390 {
391 	char path[PATH_MAX];
392 	char *end;
393 
394 	strlcpy(path, c->iri.path, sizeof(path));
395 	end = strchr(path, '\0');
396 
397 	while (end > path) {
398 		/* go up one level.  UNIX paths are simple and POSIX
399 		 * dirname, with its ambiguities on if the given path
400 		 * is changed or not, gives me headaches. */
401 		while (*end != '/')
402 			end--;
403 		*end = '\0';
404 
405 		switch (check_path(c, path, &c->pfd)) {
406 		case FILE_EXECUTABLE:
407 			start_cgi(path, end+1, c);
408 			return;
409 		case FILE_MISSING:
410 			break;
411 		default:
412 			goto err;
413 		}
414 
415 		*end = '/';
416 		end--;
417 	}
418 
419 err:
420 	start_reply(c, NOT_FOUND, "not found");
421 	return;
422 }
423 
424 void
425 mark_nonblock(int fd)
426 {
427 	int flags;
428 
429 	if ((flags = fcntl(fd, F_GETFL)) == -1)
430 		fatal("fcntl(F_GETFL): %s", strerror(errno));
431 	if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1)
432 		fatal("fcntl(F_SETFL): %s", strerror(errno));
433 }
434 
435 static void
436 handle_handshake(int fd, short ev, void *d)
437 {
438 	struct client *c = d;
439 	struct vhost *h;
440 	struct alist *a;
441 	const char *servname;
442 	const char *parse_err = "unknown error";
443 
444 	switch (tls_handshake(c->ctx)) {
445 	case 0:  /* success */
446 	case -1: /* already handshaked */
447 		break;
448 	case TLS_WANT_POLLIN:
449 		yield_read(fd, c, &handle_handshake);
450 		return;
451 	case TLS_WANT_POLLOUT:
452 		yield_write(fd, c, &handle_handshake);
453 		return;
454 	default:
455 		/* unreachable */
456 		abort();
457 	}
458 
459 	servname = tls_conn_servername(c->ctx);
460 	if (!puny_decode(servname, c->domain, sizeof(c->domain), &parse_err)) {
461 		log_info(c, "puny_decode: %s", parse_err);
462 		goto err;
463 	}
464 
465 	TAILQ_FOREACH(h, &hosts, vhosts) {
466 		if (matches(h->domain, c->domain))
467 			goto found;
468 		TAILQ_FOREACH(a, &h->aliases, aliases) {
469 			if (matches(a->alias, c->domain))
470 				goto found;
471 		}
472 	}
473 
474 found:
475 	log_debug(c, "handshake: SNI: \"%s\"; decoded: \"%s\"; matched: \"%s\"",
476 	    servname != NULL ? servname : "(null)",
477 	    c->domain,
478 	    h != NULL ? h->domain : "(null)");
479 
480 	if (h != NULL) {
481 		c->host = h;
482 		handle_open_conn(fd, ev, c);
483 		return;
484 	}
485 
486 err:
487 	if (servname != NULL)
488 		strncpy(c->req, servname, sizeof(c->req));
489 	else
490 		strncpy(c->req, "null", sizeof(c->req));
491 
492 	start_reply(c, BAD_REQUEST, "Wrong/malformed host or missing SNI");
493 }
494 
495 static char *
496 strip_path(char *path, int strip)
497 {
498 	char *t;
499 
500 	while (strip > 0) {
501 		if ((t = strchr(path, '/')) == NULL) {
502 			path = strchr(path, '\0');
503 			break;
504 		}
505 		path = t;
506 		strip--;
507 	}
508 
509 	return path;
510 }
511 
512 static void
513 fmt_sbuf(const char *fmt, struct client *c, const char *path)
514 {
515 	size_t i;
516         char buf[32];
517 
518 	memset(buf, 0, sizeof(buf));
519 	for (i = 0; *fmt; ++fmt) {
520 		if (i == sizeof(buf)-1 || *fmt == '%') {
521 			strlcat(c->sbuf, buf, sizeof(c->sbuf));
522 			memset(buf, 0, sizeof(buf));
523 			i = 0;
524 		}
525 
526 		if (*fmt != '%') {
527 			buf[i++] = *fmt;
528 			continue;
529 		}
530 
531 		switch (*++fmt) {
532 		case '%':
533 			strlcat(c->sbuf, "%", sizeof(c->sbuf));
534 			break;
535 		case 'p':
536 			if (*path != '/')
537 				strlcat(c->sbuf, "/", sizeof(c->sbuf));
538 			strlcat(c->sbuf, path, sizeof(c->sbuf));
539 			break;
540 		case 'q':
541 			strlcat(c->sbuf, c->iri.query, sizeof(c->sbuf));
542 			break;
543 		case 'P':
544 			snprintf(buf, sizeof(buf), "%d", conf.port);
545 			strlcat(c->sbuf, buf, sizeof(c->sbuf));
546 			memset(buf, 0, sizeof(buf));
547 			break;
548 		case 'N':
549 			strlcat(c->sbuf, c->domain, sizeof(c->sbuf));
550 			break;
551 		default:
552 			fatal("%s: unknown fmt specifier %c",
553 			    __func__, *fmt);
554 		}
555 	}
556 
557 	if (i != 0)
558 		strlcat(c->sbuf, buf, sizeof(c->sbuf));
559 }
560 
561 /* 1 if a matching `block return' (and apply it), 0 otherwise */
562 static int
563 apply_block_return(struct client *c)
564 {
565 	const char *fmt, *path;
566 	int code;
567 
568 	if (!vhost_block_return(c->host, c->iri.path, &code, &fmt))
569 		return 0;
570 
571 	path = strip_path(c->iri.path, vhost_strip(c->host, c->iri.path));
572 	fmt_sbuf(fmt, c, path);
573 
574 	start_reply(c, code, c->sbuf);
575 	return 1;
576 }
577 
578 /* 1 if matching `fcgi' (and apply it), 0 otherwise */
579 static int
580 apply_fastcgi(struct client *c)
581 {
582 	int		 id;
583 	struct fcgi	*f;
584 
585 	if ((id = vhost_fastcgi(c->host, c->iri.path)) == -1)
586 		return 0;
587 
588 	switch ((f = &fcgi[id])->s) {
589 	case FCGI_OFF:
590 		f->s = FCGI_INFLIGHT;
591 		log_info(c, "opening fastcgi connection for (%s,%s,%s)",
592 		    f->path, f->port, f->prog);
593 		imsg_compose(&exibuf, IMSG_FCGI_REQ, 0, 0, -1,
594 		    &id, sizeof(id));
595 		imsg_flush(&exibuf);
596                 /* fallthrough */
597 	case FCGI_INFLIGHT:
598                 c->fcgi = id;
599 		break;
600 	case FCGI_READY:
601                 c->fcgi = id;
602 		send_fcgi_req(f, c);
603 		break;
604 	}
605 
606 	return 1;
607 }
608 
609 /* 1 if matching `require client ca' fails (and apply it), 0 otherwise */
610 static int
611 apply_require_ca(struct client *c)
612 {
613 	X509_STORE	*store;
614 	const uint8_t	*cert;
615 	size_t		 len;
616 
617 	if ((store = vhost_require_ca(c->host, c->iri.path)) == NULL)
618 		return 0;
619 
620 	if (!tls_peer_cert_provided(c->ctx)) {
621 		start_reply(c, CLIENT_CERT_REQ, "client certificate required");
622 		return 1;
623 	}
624 
625 	cert = tls_peer_cert_chain_pem(c->ctx, &len);
626 	if (!validate_against_ca(store, cert, len)) {
627 		start_reply(c, CERT_NOT_AUTH, "certificate not authorised");
628 		return 1;
629 	}
630 
631 	return 0;
632 }
633 
634 static void
635 handle_open_conn(int fd, short ev, void *d)
636 {
637 	struct client *c = d;
638 	const char *parse_err = "invalid request";
639 	char decoded[DOMAIN_NAME_LEN];
640 
641 	bzero(c->req, sizeof(c->req));
642 	bzero(&c->iri, sizeof(c->iri));
643 
644 	switch (tls_read(c->ctx, c->req, sizeof(c->req)-1)) {
645 	case -1:
646 		log_err(c, "tls_read: %s", tls_error(c->ctx));
647 		close_conn(fd, ev, c);
648 		return;
649 
650 	case TLS_WANT_POLLIN:
651 		yield_read(fd, c, &handle_open_conn);
652 		return;
653 
654 	case TLS_WANT_POLLOUT:
655 		yield_write(fd, c, &handle_open_conn);
656 		return;
657 	}
658 
659 	if (!trim_req_iri(c->req, &parse_err)
660 	    || !parse_iri(c->req, &c->iri, &parse_err)
661 	    || !puny_decode(c->iri.host, decoded, sizeof(decoded), &parse_err)) {
662 		log_info(c, "iri parse error: %s", parse_err);
663 		start_reply(c, BAD_REQUEST, "invalid request");
664 		return;
665 	}
666 
667 	if (c->iri.port_no != conf.port
668 	    || strcmp(c->iri.schema, "gemini")
669 	    || strcmp(decoded, c->domain)) {
670 		start_reply(c, PROXY_REFUSED, "won't proxy request");
671 		return;
672 	}
673 
674 	if (apply_require_ca(c))
675 		return;
676 
677 	if (apply_block_return(c))
678 		return;
679 
680 	if (apply_fastcgi(c))
681 		return;
682 
683 	if (c->host->entrypoint != NULL) {
684 		start_cgi(c->host->entrypoint, c->iri.path, c);
685 		return;
686 	}
687 
688 	open_file(c);
689 }
690 
691 void
692 start_reply(struct client *c, int code, const char *meta)
693 {
694 	c->code = code;
695 	c->meta = meta;
696 	handle_start_reply(c->fd, 0, c);
697 }
698 
699 static void
700 handle_start_reply(int fd, short ev, void *d)
701 {
702 	struct client *c = d;
703 	char buf[1030];		/* status + ' ' + max reply len + \r\n\0 */
704 	const char *lang;
705 	size_t len;
706 
707 	lang = vhost_lang(c->host, c->iri.path);
708 
709 	snprintf(buf, sizeof(buf), "%d ", c->code);
710 	strlcat(buf, c->meta, sizeof(buf));
711 	if (!strcmp(c->meta, "text/gemini") && lang != NULL) {
712 		strlcat(buf, "; lang=", sizeof(buf));
713 		strlcat(buf, lang, sizeof(buf));
714 	}
715 
716 	len = strlcat(buf, "\r\n", sizeof(buf));
717 	assert(len < sizeof(buf));
718 
719 	switch (tls_write(c->ctx, buf, len)) {
720 	case -1:
721 		close_conn(fd, ev, c);
722 		return;
723 	case TLS_WANT_POLLIN:
724 		yield_read(fd, c, &handle_start_reply);
725 		return;
726 	case TLS_WANT_POLLOUT:
727 		yield_write(fd, c, &handle_start_reply);
728 		return;
729 	}
730 
731 	if (!vhost_disable_log(c->host, c->iri.path))
732 		log_request(c, buf, sizeof(buf));
733 
734 	if (c->code != SUCCESS)
735 		close_conn(fd, ev, c);
736 	else
737 		c->next(fd, ev, c);
738 }
739 
740 static size_t
741 host_nth(struct vhost *h)
742 {
743 	struct vhost	*v;
744 	size_t		 i = 0;
745 
746 	TAILQ_FOREACH(v, &hosts, vhosts) {
747 		if (v == h)
748 			return i;
749 		i++;
750 	}
751 
752 	abort();
753 }
754 
755 static void
756 start_cgi(const char *spath, const char *relpath, struct client *c)
757 {
758 	char addr[NI_MAXHOST];
759 	const char *t;
760 	struct cgireq req;
761 	int e;
762 
763 	e = getnameinfo((struct sockaddr*)&c->addr, sizeof(c->addr),
764 	    addr, sizeof(addr),
765 	    NULL, 0,
766 	    NI_NUMERICHOST);
767 	if (e != 0)
768 		fatal("getnameinfo failed");
769 
770 	memset(&req, 0, sizeof(req));
771 
772 	memcpy(req.buf, c->req, sizeof(req.buf));
773 
774 	req.iri_schema_off = c->iri.schema - c->req;
775 	req.iri_host_off = c->iri.host - c->req;
776 	req.iri_port_off = c->iri.port - c->req;
777 	req.iri_path_off = c->iri.path - c->req;
778 	req.iri_query_off = c->iri.query - c->req;
779 	req.iri_fragment_off = c->iri.fragment - c->req;
780 
781 	req.iri_portno = c->iri.port_no;
782 
783 	strlcpy(req.spath, spath, sizeof(req.spath));
784 	strlcpy(req.relpath, relpath, sizeof(req.relpath));
785 	strlcpy(req.addr, addr, sizeof(req.addr));
786 
787 	if ((t = tls_peer_cert_subject(c->ctx)) != NULL)
788 		strlcpy(req.subject, t, sizeof(req.subject));
789 	if ((t = tls_peer_cert_issuer(c->ctx)) != NULL)
790 		strlcpy(req.issuer, t, sizeof(req.issuer));
791 	if ((t = tls_peer_cert_hash(c->ctx)) != NULL)
792 		strlcpy(req.hash, t, sizeof(req.hash));
793 	if ((t = tls_conn_version(c->ctx)) != NULL)
794 		strlcpy(req.version, t, sizeof(req.version));
795 	if ((t = tls_conn_cipher(c->ctx)) != NULL)
796 		strlcpy(req.cipher, t, sizeof(req.cipher));
797 
798 	req.cipher_strength = tls_conn_cipher_strength(c->ctx);
799 	req.notbefore = tls_peer_cert_notbefore(c->ctx);
800 	req.notafter = tls_peer_cert_notafter(c->ctx);
801 
802 	req.host_off = host_nth(c->host);
803 
804 	imsg_compose(&exibuf, IMSG_CGI_REQ, c->id, 0, -1, &req, sizeof(req));
805 	imsg_flush(&exibuf);
806 
807 	close(c->pfd);
808 }
809 
810 static void
811 open_dir(struct client *c)
812 {
813 	size_t len;
814 	int dirfd, root;
815 	char *before_file;
816 
817 	root = !strcmp(c->iri.path, "/") || *c->iri.path == '\0';
818 
819 	len = strlen(c->iri.path);
820 	if (len > 0 && !ends_with(c->iri.path, "/")) {
821 		redirect_canonical_dir(c);
822 		return;
823 	}
824 
825 	strlcpy(c->sbuf, "/", sizeof(c->sbuf));
826 	strlcat(c->sbuf, c->iri.path, sizeof(c->sbuf));
827 	if (!ends_with(c->sbuf, "/"))
828 		strlcat(c->sbuf, "/", sizeof(c->sbuf));
829 	before_file = strchr(c->sbuf, '\0');
830 	len = strlcat(c->sbuf, vhost_index(c->host, c->iri.path),
831 	    sizeof(c->sbuf));
832 	if (len >= sizeof(c->sbuf)) {
833 		start_reply(c, TEMP_FAILURE, "internal server error");
834 		return;
835 	}
836 
837 	c->iri.path = c->sbuf;
838 
839 	/* close later unless we have to generate the dir listing */
840 	dirfd = c->pfd;
841 	c->pfd = -1;
842 
843 	switch (check_path(c, c->iri.path, &c->pfd)) {
844 	case FILE_EXECUTABLE:
845 		if (c->host->cgi != NULL && matches(c->host->cgi, c->iri.path)) {
846 			start_cgi(c->iri.path, "", c);
847 			break;
848 		}
849 
850 		/* fallthrough */
851 
852 	case FILE_EXISTS:
853 		c->next = handle_copy;
854 		start_reply(c, SUCCESS, mime(c->host, c->iri.path));
855 		break;
856 
857 	case FILE_DIRECTORY:
858 		start_reply(c, TEMP_REDIRECT, c->sbuf);
859 		break;
860 
861 	case FILE_MISSING:
862 		*before_file = '\0';
863 
864 		if (!vhost_auto_index(c->host, c->iri.path)) {
865 			start_reply(c, NOT_FOUND, "not found");
866 			break;
867 		}
868 
869 		c->next = enter_handle_dirlist;
870 
871 		c->dirlen = scandir_fd(dirfd, &c->dir,
872 		    root ? select_non_dotdot : select_non_dot,
873 		    alphasort);
874 		if (c->dirlen == -1) {
875 			log_err(c, "scandir_fd(%d) (vhost:%s) %s: %s",
876 			    c->pfd, c->host->domain, c->iri.path, strerror(errno));
877 			start_reply(c, TEMP_FAILURE, "internal server error");
878 			return;
879 		}
880 		c->diroff = 0;
881 		c->off = 0;
882 
883                 start_reply(c, SUCCESS, "text/gemini");
884 		return;
885 
886 	default:
887 		/* unreachable */
888 		abort();
889 	}
890 
891 	close(dirfd);
892 }
893 
894 static void
895 redirect_canonical_dir(struct client *c)
896 {
897 	size_t len;
898 
899 	strlcpy(c->sbuf, "/", sizeof(c->sbuf));
900 	strlcat(c->sbuf, c->iri.path, sizeof(c->sbuf));
901 	len = strlcat(c->sbuf, "/", sizeof(c->sbuf));
902 
903 	if (len >= sizeof(c->sbuf)) {
904 		start_reply(c, TEMP_FAILURE, "internal server error");
905 		return;
906 	}
907 
908 	start_reply(c, TEMP_REDIRECT, c->sbuf);
909 }
910 
911 static void
912 enter_handle_dirlist(int fd, short ev, void *d)
913 {
914 	struct client *c = d;
915 	char b[PATH_MAX];
916 	size_t l;
917 
918 	strlcpy(b, c->iri.path, sizeof(b));
919 	l = snprintf(c->sbuf, sizeof(c->sbuf),
920 	    "# Index of %s\n\n", b);
921 	if (l >= sizeof(c->sbuf)) {
922 		/* this is impossible, given that we have enough space
923 		 * in c->sbuf to hold the ancilliary string plus the
924 		 * full path; but it wouldn't read nice without some
925 		 * error checking, and I'd like to avoid a strlen. */
926 		close_conn(fd, ev, c);
927 		return;
928 	}
929 
930 	c->len = l;
931 	handle_dirlist(fd, ev, c);
932 }
933 
934 static void
935 handle_dirlist(int fd, short ev, void *d)
936 {
937 	struct client *c = d;
938 	ssize_t r;
939 
940 	while (c->len > 0) {
941 		switch (r = tls_write(c->ctx, c->sbuf + c->off, c->len)) {
942 		case -1:
943 			close_conn(fd, ev, c);
944 			return;
945 		case TLS_WANT_POLLOUT:
946 			yield_read(fd, c, &handle_dirlist);
947 			return;
948 		case TLS_WANT_POLLIN:
949 			yield_write(fd, c, &handle_dirlist);
950 			return;
951 		default:
952 			c->off += r;
953 			c->len -= r;
954 		}
955 	}
956 
957 	send_directory_listing(fd, ev, c);
958 }
959 
960 static int
961 read_next_dir_entry(struct client *c)
962 {
963 	if (c->diroff == c->dirlen)
964 		return 0;
965 
966 	/* XXX: url escape */
967 	snprintf(c->sbuf, sizeof(c->sbuf), "=> %s\n",
968 	    c->dir[c->diroff]->d_name);
969 
970 	free(c->dir[c->diroff]);
971 	c->diroff++;
972 
973 	c->len = strlen(c->sbuf);
974 	c->off = 0;
975 	return 1;
976 }
977 
978 static void
979 send_directory_listing(int fd, short ev, void *d)
980 {
981 	struct client *c = d;
982 	ssize_t r;
983 
984 	while (1) {
985 		if (c->len == 0) {
986 			if (!read_next_dir_entry(c))
987 				goto end;
988 		}
989 
990 		while (c->len > 0) {
991 			switch (r = tls_write(c->ctx, c->sbuf + c->off, c->len)) {
992 			case -1:
993 				goto end;
994 
995 			case TLS_WANT_POLLOUT:
996 				yield_read(fd, c, &send_directory_listing);
997 				return;
998 
999 			case TLS_WANT_POLLIN:
1000 				yield_write(fd, c, &send_directory_listing);
1001 				return;
1002 
1003 			default:
1004 				c->off += r;
1005 				c->len -= r;
1006 				break;
1007 			}
1008 		}
1009 	}
1010 
1011 end:
1012 	close_conn(fd, ev, d);
1013 }
1014 
1015 /* accumulate the meta line from the cgi script. */
1016 static void
1017 handle_cgi_reply(int fd, short ev, void *d)
1018 {
1019 	struct client *c = d;
1020 	void	*buf, *e;
1021 	size_t	 len;
1022 	ssize_t	 r;
1023 
1024 
1025 	buf = c->sbuf + c->len;
1026 	len = sizeof(c->sbuf) - c->len;
1027 
1028 	r = read(c->pfd, buf, len);
1029 	if (r == 0 || r == -1) {
1030 		start_reply(c, CGI_ERROR, "CGI error");
1031 		return;
1032 	}
1033 
1034 	c->len += r;
1035 
1036 	/* TODO: error if the CGI script don't reply correctly */
1037 	e = strchr(c->sbuf, '\n');
1038 	if (e != NULL || c->len == sizeof(c->sbuf)) {
1039 		log_request(c, c->sbuf, c->len);
1040 
1041 		c->off = 0;
1042 		handle_copy(fd, ev, c);
1043 		return;
1044 	}
1045 
1046 	yield_read(fd, c, &handle_cgi_reply);
1047 }
1048 
1049 static void
1050 handle_copy(int fd, short ev, void *d)
1051 {
1052 	struct client *c = d;
1053 	ssize_t r;
1054 
1055 	while (1) {
1056 		while (c->len > 0) {
1057 			switch (r = tls_write(c->ctx, c->sbuf + c->off, c->len)) {
1058 			case -1:
1059 				goto end;
1060 
1061 			case TLS_WANT_POLLOUT:
1062 				yield_write(c->fd, c, &handle_copy);
1063 				return;
1064 
1065 			case TLS_WANT_POLLIN:
1066 				yield_read(c->fd, c, &handle_copy);
1067 				return;
1068 
1069 			default:
1070                                 c->off += r;
1071 				c->len -= r;
1072 				break;
1073 			}
1074 		}
1075 
1076 		switch (r = read(c->pfd, c->sbuf, sizeof(c->sbuf))) {
1077 		case 0:
1078 			goto end;
1079 		case -1:
1080 			if (errno == EAGAIN || errno == EWOULDBLOCK) {
1081 				yield_read(c->pfd, c, &handle_copy);
1082 				return;
1083 			}
1084 			goto end;
1085 		default:
1086 			c->len = r;
1087 			c->off = 0;
1088 		}
1089 	}
1090 
1091 end:
1092 	close_conn(c->fd, ev, d);
1093 }
1094 
1095 void
1096 close_conn(int fd, short ev, void *d)
1097 {
1098 	struct client	*c = d;
1099 	struct mbuf	*mbuf;
1100 
1101 	switch (tls_close(c->ctx)) {
1102 	case TLS_WANT_POLLIN:
1103 		yield_read(fd, c, &close_conn);
1104 		return;
1105 	case TLS_WANT_POLLOUT:
1106 		yield_read(fd, c, &close_conn);
1107 		return;
1108 	}
1109 
1110 	connected_clients--;
1111 
1112 	while ((mbuf = TAILQ_FIRST(&c->mbufhead)) != NULL) {
1113 		TAILQ_REMOVE(&c->mbufhead, mbuf, mbufs);
1114 		free(mbuf);
1115 	}
1116 
1117 	tls_free(c->ctx);
1118 	c->ctx = NULL;
1119 
1120 	if (c->pfd != -1)
1121 		close(c->pfd);
1122 
1123 	if (c->dir != NULL)
1124 		free(c->dir);
1125 
1126 	close(c->fd);
1127 	c->fd = -1;
1128 }
1129 
1130 static void
1131 do_accept(int sock, short et, void *d)
1132 {
1133 	struct client *c;
1134 	struct sockaddr_storage addr;
1135 	struct sockaddr *saddr;
1136 	socklen_t len;
1137 	int i, fd;
1138 
1139 	(void)et;
1140 
1141 	saddr = (struct sockaddr*)&addr;
1142 	len = sizeof(addr);
1143 	if ((fd = accept(sock, saddr, &len)) == -1) {
1144 		if (errno == EWOULDBLOCK || errno == EAGAIN)
1145 			return;
1146 		fatal("accept: %s", strerror(errno));
1147 	}
1148 
1149 	mark_nonblock(fd);
1150 
1151 	for (i = 0; i < MAX_USERS; ++i) {
1152 		c = &clients[i];
1153 		if (c->fd == -1) {
1154 			memset(c, 0, sizeof(*c));
1155 			c->id = i;
1156 			if (tls_accept_socket(ctx, &c->ctx, fd) == -1)
1157 				break; /* goodbye fd! */
1158 
1159 			c->fd = fd;
1160 			c->pfd = -1;
1161 			c->dir = NULL;
1162 			c->addr = addr;
1163 			c->fcgi = -1;
1164 
1165 			yield_read(fd, c, &handle_handshake);
1166 			connected_clients++;
1167 			return;
1168 		}
1169 	}
1170 
1171 	close(fd);
1172 }
1173 
1174 static struct client *
1175 client_by_id(int id)
1176 {
1177 	if ((size_t)id > sizeof(clients)/sizeof(clients[0]))
1178 		fatal("in client_by_id: invalid id %d", id);
1179 	return &clients[id];
1180 }
1181 
1182 struct client *
1183 try_client_by_id(int id)
1184 {
1185 	if ((size_t)id > sizeof(clients)/sizeof(clients[0]))
1186                 return NULL;
1187 	return &clients[id];
1188 }
1189 
1190 static void
1191 handle_imsg_cgi_res(struct imsgbuf *ibuf, struct imsg *imsg, size_t len)
1192 {
1193 	struct client *c;
1194 
1195 	c = client_by_id(imsg->hdr.peerid);
1196 
1197 	if ((c->pfd = imsg->fd) == -1)
1198 		start_reply(c, TEMP_FAILURE, "internal server error");
1199 	else
1200 		yield_read(c->pfd, c, &handle_cgi_reply);
1201 }
1202 
1203 static void
1204 handle_imsg_fcgi_fd(struct imsgbuf *ibuf, struct imsg *imsg, size_t len)
1205 {
1206 	struct client	*c;
1207 	struct fcgi	*f;
1208 	int		 i, id;
1209 
1210 	id = imsg->hdr.peerid;
1211 	f = &fcgi[id];
1212 
1213 	if ((f->fd = imsg->fd) != -1) {
1214 		event_set(&f->e, imsg->fd, EV_READ | EV_PERSIST, &handle_fcgi,
1215 		    &fcgi[id]);
1216 		event_add(&f->e, NULL);
1217 	} else {
1218 		f->s = FCGI_OFF;
1219 	}
1220 
1221 	for (i = 0; i < MAX_USERS; ++i) {
1222 		c = &clients[i];
1223 		if (c->fd == -1)
1224 			continue;
1225 		if (c->fcgi != id)
1226 			continue;
1227 
1228 		if (f->fd == -1) {
1229 			c->fcgi = -1;
1230 			start_reply(c, TEMP_FAILURE, "internal server error");
1231 		} else
1232 			send_fcgi_req(f, c);
1233 	}
1234 }
1235 
1236 static void
1237 handle_imsg_quit(struct imsgbuf *ibuf, struct imsg *imsg, size_t len)
1238 {
1239 	(void)imsg;
1240 	(void)len;
1241 
1242 	/* don't call event_loopbreak since we want to finish to
1243 	 * handle the ongoing connections. */
1244 
1245 	event_del(&e4);
1246 	if (has_ipv6)
1247 		event_del(&e6);
1248 	if (has_siginfo)
1249 		signal_del(&siginfo);
1250 	event_del(&imsgev);
1251 	signal_del(&sigusr2);
1252 }
1253 
1254 static void
1255 handle_dispatch_imsg(int fd, short ev, void *d)
1256 {
1257 	struct imsgbuf *ibuf = d;
1258 	dispatch_imsg(ibuf, handlers, sizeof(handlers));
1259 }
1260 
1261 static void
1262 handle_siginfo(int fd, short ev, void *d)
1263 {
1264 	(void)fd;
1265 	(void)ev;
1266 	(void)d;
1267 
1268 	log_info(NULL, "%d connected clients", connected_clients);
1269 }
1270 
1271 void
1272 loop(struct tls *ctx_, int sock4, int sock6, struct imsgbuf *ibuf)
1273 {
1274 	size_t i;
1275 
1276 	ctx = ctx_;
1277 
1278 	event_init();
1279 
1280 	memset(&clients, 0, sizeof(clients));
1281 	for (i = 0; i < MAX_USERS; ++i)
1282 		clients[i].fd = -1;
1283 
1284 	event_set(&e4, sock4, EV_READ | EV_PERSIST, &do_accept, NULL);
1285 	event_add(&e4, NULL);
1286 
1287 	if (sock6 != -1) {
1288 		has_ipv6 = 1;
1289 		event_set(&e6, sock6, EV_READ | EV_PERSIST, &do_accept, NULL);
1290 		event_add(&e6, NULL);
1291 	}
1292 
1293 	event_set(&imsgev, ibuf->fd, EV_READ | EV_PERSIST, handle_dispatch_imsg, ibuf);
1294 	event_add(&imsgev, NULL);
1295 
1296 #ifdef SIGINFO
1297 	has_siginfo = 1;
1298 	signal_set(&siginfo, SIGINFO, &handle_siginfo, NULL);
1299 	signal_add(&siginfo, NULL);
1300 #endif
1301 	signal_set(&sigusr2, SIGUSR2, &handle_siginfo, NULL);
1302 	signal_add(&sigusr2, NULL);
1303 
1304 	sandbox_server_process();
1305 	event_dispatch();
1306 	_exit(0);
1307 }