1 /*
2  * Copyright (c) 2020 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 <sys/mman.h>
18 #include <sys/socket.h>
19 #include <sys/stat.h>
20 
21 #include <arpa/inet.h>
22 #include <netinet/in.h>
23 
24 #include <assert.h>
25 #include <err.h>
26 #include <errno.h>
27 #include <fcntl.h>
28 #include <poll.h>
29 #include <signal.h>
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include <tls.h>
34 #include <unistd.h>
35 
36 #ifndef __OpenBSD__
37 # define pledge(a, b) 0
38 # define unveil(a, b) 0
39 #endif /* __OpenBSD__ */
40 
41 #ifndef INFTIM
42 # define INFTIM -1
43 #endif /* INFTIM */
44 
45 #define GEMINI_URL_LEN (1024+3)	/* URL max len + \r\n + \0 */
46 
47 /* large enough to hold a copy of a gemini URL and still have extra room */
48 #define PATHBUF		2048
49 
50 #define SUCCESS		20
51 #define TEMP_FAILURE	40
52 #define NOT_FOUND	51
53 #define BAD_REQUEST	59
54 
55 #ifndef MAX_USERS
56 #define MAX_USERS	64
57 #endif
58 
59 enum {
60 	S_OPEN,
61 	S_INITIALIZING,
62 	S_SENDING,
63 	S_CLOSING,
64 };
65 
66 struct client {
67 	struct tls	*ctx;
68 	int		 state;
69 	int		 code;
70 	const char	*meta;
71 	int		 fd, waiting_on_child;
72 	pid_t		 child;
73 	char		 sbuf[1024];	  /* static buffer */
74 	void		*buf, *i;	  /* mmap buffer */
75 	ssize_t		 len, off;	  /* mmap/static buffer  */
76 	int		 af;
77 	struct in_addr	 addr;
78 };
79 
80 struct etm {			/* file extension to mime */
81 	const char	*mime;
82 	const char	*ext;
83 } filetypes[] = {
84 	{"application/pdf",	"pdf"},
85 
86 	{"image/gif",		"gif"},
87 	{"image/jpeg",		"jpg"},
88 	{"image/jpeg",		"jpeg"},
89 	{"image/png",		"png"},
90 	{"image/svg+xml",	"svg"},
91 
92 	{"text/gemini",		"gemini"},
93 	{"text/gemini",		"gmi"},
94 	{"text/markdown",	"markdown"},
95 	{"text/markdown",	"md"},
96 	{"text/plain",		"txt"},
97 	{"text/xml",		"xml"},
98 
99 	{NULL, NULL}
100 };
101 
102 #define LOG(c, fmt, ...)						\
103 	do {								\
104 		char buf[INET_ADDRSTRLEN];				\
105 		if (inet_ntop((c)->af, &(c)->addr, buf, sizeof(buf)) == NULL) \
106 			err(1, "inet_ntop");				\
107 		dprintf(logfd, "[%s] " fmt "\n", buf, __VA_ARGS__);	\
108 	} while (0)
109 
110 const char *dir;
111 int dirfd, logfd;
112 int cgi;
113 
114 char		*url_after_proto(char*);
115 char		*url_start_of_request(char*);
116 int		 url_trim(struct client*, char*);
117 char		*adjust_path(char*);
118 int		 path_isdir(char*);
119 ssize_t		 filesize(int);
120 
121 int		 start_reply(struct pollfd*, struct client*, int, const char*);
122 const char	*path_ext(const char*);
123 const char	*mime(const char*);
124 int		 open_file(char*, char*, struct pollfd*, struct client*);
125 void		 start_cgi(const char*, const char*, struct pollfd*, struct client*);
126 void		 cgi_setpoll_on_child(struct pollfd*, struct client*);
127 void		 cgi_setpoll_on_client(struct pollfd*, struct client*);
128 void		 handle_cgi(struct pollfd*, struct client*);
129 void		 send_file(char*, char*, struct pollfd*, struct client*);
130 void		 send_dir(char*, struct pollfd*, struct client*);
131 void		 handle(struct pollfd*, struct client*);
132 
133 void		 mark_nonblock(int);
134 int		 make_soket(int);
135 void		 do_accept(int, struct tls*, struct pollfd*, struct client*);
136 void		 goodbye(struct pollfd*, struct client*);
137 void		 loop(struct tls*, int);
138 
139 void		 usage(const char*);
140 
141 char *
142 url_after_proto(char *url)
143 {
144 	char *s;
145 	const char *proto = "gemini";
146 	const char *marker = "://";
147 	size_t i;
148 
149 	/* a relative URL */
150 	if ((s = strstr(url, marker)) == NULL)
151 		return url;
152 
153 	if (s - strlen(proto) != url)
154 		return NULL;
155 
156 	for (i = 0; proto[i] != '\0'; ++i)
157 		if (url[i] != proto[i])
158 			return NULL;
159 
160 	/* a valid gemini:// URL */
161 	return s + strlen(marker);
162 }
163 
164 char *
165 url_start_of_request(char *url)
166 {
167 	char *s, *t;
168 
169 	if ((s = url_after_proto(url)) == NULL)
170 		return NULL;
171 
172 	if ((t = strstr(s, "/")) == NULL)
173 		return s + strlen(s);
174 	return t;
175 }
176 
177 int
178 url_trim(struct client *c, char *url)
179 {
180 	const char *e = "\r\n";
181 	char *s;
182 
183 	if ((s = strstr(url, e)) == NULL)
184 		return 0;
185 	s[0] = '\0';
186 	s[1] = '\0';
187 
188 	if (s[2] != '\0') {
189 		LOG(c, "%s", "request longer than 1024 bytes\n");
190 		return 0;
191 	}
192 
193 	return 1;
194 }
195 
196 char *
197 adjust_path(char *path)
198 {
199 	char *s, *query;
200 	size_t len;
201 
202 	if ((query = strchr(path, '?')) != NULL) {
203 		*query = '\0';
204 		query++;
205 	}
206 
207 	/* /.. -> / */
208 	len = strlen(path);
209 	if (len >= 3) {
210 		if (!strcmp(&path[len-3], "/..")) {
211 			path[len-2] = '\0';
212 		}
213 	}
214 
215 	/* if the path is only `..` trim out and exit */
216 	if (!strcmp(path, "..")) {
217 		path[0] = '\0';
218 		return query;
219 	}
220 
221 	/* remove every ../ in the path */
222 	while (1) {
223 		if ((s = strstr(path, "../")) == NULL)
224 			return query;
225 		memmove(s, s+3, strlen(s)+1);	/* copy also the \0 */
226 	}
227 }
228 
229 int
230 path_isdir(char *path)
231 {
232 	if (*path == '\0')
233 		return 1;
234 	return path[strlen(path)-1] == '/';
235 }
236 
237 int
238 start_reply(struct pollfd *pfd, struct client *client, int code, const char *reason)
239 {
240 	char buf[1030] = {0}; 	/* status + ' ' + max reply len + \r\n\0 */
241 	int len;
242 	int ret;
243 
244 	client->code = code;
245 	client->meta = reason;
246 	client->state = S_INITIALIZING;
247 
248 	len = snprintf(buf, sizeof(buf), "%d %s\r\n", code, reason);
249 	assert(len < (int)sizeof(buf));
250 	ret = tls_write(client->ctx, buf, len);
251 	if (ret == TLS_WANT_POLLIN) {
252 		pfd->events = POLLIN;
253 		return 0;
254 	}
255 
256 	if (ret == TLS_WANT_POLLOUT) {
257 		pfd->events = POLLOUT;
258 		return 0;
259 	}
260 
261 	return 1;
262 }
263 
264 ssize_t
265 filesize(int fd)
266 {
267 	ssize_t len;
268 
269 	if ((len = lseek(fd, 0, SEEK_END)) == -1)
270 		return -1;
271 	if (lseek(fd, 0, SEEK_SET) == -1)
272 		return -1;
273 	return len;
274 }
275 
276 const char *
277 path_ext(const char *path)
278 {
279 	const char *end;
280 
281 	end = path + strlen(path)-1; /* the last byte before the NUL */
282 	for (; end != path; --end) {
283 		if (*end == '.')
284 			return end+1;
285 		if (*end == '/')
286 			break;
287 	}
288 
289 	return NULL;
290 }
291 
292 const char *
293 mime(const char *path)
294 {
295 	const char *ext, *def = "application/octet-stream";
296 	struct etm *t;
297 
298 	if ((ext = path_ext(path)) == NULL)
299 		return def;
300 
301 	for (t = filetypes; t->mime != NULL; ++t)
302 		if (!strcmp(ext, t->ext))
303 			return t->mime;
304 
305 	return def;
306 }
307 
308 int
309 open_file(char *path, char *query, struct pollfd *fds, struct client *c)
310 {
311 	char fpath[PATHBUF];
312 	struct stat sb;
313 
314 	assert(path != NULL);
315 
316 	bzero(fpath, sizeof(fpath));
317 
318 	if (*path != '.')
319 		fpath[0] = '.';
320 	strlcat(fpath, path, PATHBUF);
321 
322 	if ((c->fd = openat(dirfd, fpath,
323 		    O_RDONLY | O_NOFOLLOW | O_CLOEXEC)) == -1) {
324 		LOG(c, "open failed: %s", fpath);
325 		if (!start_reply(fds, c, NOT_FOUND, "not found"))
326 			return 0;
327 		goodbye(fds, c);
328 		return 0;
329 	}
330 
331 	if (fstat(c->fd, &sb) == -1) {
332 		LOG(c, "fstat failed for %s", fpath);
333 		if (!start_reply(fds, c, TEMP_FAILURE, "internal server error"))
334 			return 0;
335 		goodbye(fds, c);
336 		return 0;
337 	}
338 
339 	if (S_ISDIR(sb.st_mode)) {
340 		LOG(c, "%s is a directory, trying %s/index.gmi", fpath, fpath);
341 		close(c->fd);
342 		c->fd = -1;
343 		send_dir(fpath, fds, c);
344 		return 0;
345 	}
346 
347 	if (cgi && (sb.st_mode & S_IXUSR)) {
348 		start_cgi(fpath, query, fds, c);
349 		return 0;
350 	}
351 
352 	if ((c->len = filesize(c->fd)) == -1) {
353 		LOG(c, "failed to get file size for %s", fpath);
354 		goodbye(fds, c);
355 		return 0;
356 	}
357 
358 	if ((c->buf = mmap(NULL, c->len, PROT_READ, MAP_PRIVATE,
359 		    c->fd, 0)) == MAP_FAILED) {
360 		warn("mmap: %s", fpath);
361 		goodbye(fds, c);
362 		return 0;
363 	}
364 	c->i = c->buf;
365 
366 	return start_reply(fds, c, SUCCESS, mime(fpath));
367 }
368 
369 void
370 start_cgi(const char *path, const char *query,
371     struct pollfd *fds, struct client *c)
372 {
373 	pid_t pid;
374 	int p[2];
375 
376 	if (pipe(p) == -1)
377 		goto err;
378 
379 	switch (pid = fork()) {
380 	case -1:
381 		goto err;
382 
383 	case 0: {		/* child */
384                 char *expath;
385 		char addr[INET_ADDRSTRLEN];
386 		char *argv[] = { NULL, NULL, NULL };
387 
388 		/* skip the initial ./ */
389 		path += 2;
390 
391 		close(p[0]);	/* close the read end */
392 		if (dup2(p[1], 1) == -1)
393 			goto childerr;
394 
395 		if (inet_ntop(c->af, &c->addr, addr, sizeof(addr)) == NULL)
396                         goto childerr;
397 
398 		/* skip the ./ at the start of path*/
399 		if (asprintf(&expath, "%s%s", dir, path) == -1)
400 			goto childerr;
401 		argv[0] = argv[1] = expath;
402 
403 		/* fix the env */
404 		setenv("SERVER_SOFTWARE", "gmid", 1);
405 		/* setenv("SERVER_NAME", "", 1); */
406 		/* setenv("GATEWAY_INTERFACE", "CGI/version", 1); */
407 		setenv("SERVER_PROTOCOL", "gemini", 1);
408 		setenv("SERVER_PORT", "1965", 1);
409 		setenv("PATH_INFO", path, 1);
410 		setenv("PATH_TRANSLATED", expath, 1);
411 		setenv("QUERY_STRING", query ? query : "", 1);
412 		setenv("REMOTE_ADDR", addr, 1);
413 
414 		execvp(expath, argv);
415 		goto childerr;
416 	}
417 
418 	default:		/* parent */
419 		close(p[1]);	/* close the write end */
420 		close(c->fd);
421 		c->fd = p[0];
422 		c->child = pid;
423 		mark_nonblock(c->fd);
424 		c->state = S_SENDING;
425 		handle_cgi(fds, c);
426 		return;
427 	}
428 
429 err:
430 	if (!start_reply(fds, c, TEMP_FAILURE, "internal server error"))
431 		return;
432 	goodbye(fds, c);
433 	return;
434 
435 childerr:
436 	dprintf(p[1], "%d internal server error\r\n", TEMP_FAILURE);
437 	close(p[1]);
438 
439 	/* don't call atexit stuff */
440         _exit(1);
441 }
442 
443 void
444 cgi_setpoll_on_child(struct pollfd *fds, struct client *c)
445 {
446 	int fd;
447 
448 	if (c->waiting_on_child)
449 		return;
450 	c->waiting_on_child = 1;
451 
452 	fds->events = POLLIN;
453 
454 	fd = fds->fd;
455 	fds->fd = c->fd;
456 	c->fd = fd;
457 }
458 
459 void
460 cgi_setpoll_on_client(struct pollfd *fds, struct client *c)
461 {
462 	int fd;
463 
464 	if (!c->waiting_on_child)
465 		return;
466 	c->waiting_on_child = 0;
467 
468 	fd = fds->fd;
469 	fds->fd = c->fd;
470 	c->fd = fd;
471 }
472 
473 void
474 handle_cgi(struct pollfd *fds, struct client *c)
475 {
476 	ssize_t r;
477 
478 	/* ensure c->fd is the child and fds->fd the client */
479 	cgi_setpoll_on_client(fds, c);
480 
481 	while (1) {
482 		if (c->len == 0) {
483 			if ((r = read(c->fd, c->sbuf, sizeof(c->sbuf))) == 0)
484 				goto end;
485 			if (r == -1) {
486 				if (errno == EAGAIN || errno == EWOULDBLOCK) {
487 					cgi_setpoll_on_child(fds, c);
488 					return;
489 				}
490                                 goto end;
491 			}
492 			c->len = r;
493 			c->off = 0;
494 		}
495 
496 		while (c->len > 0) {
497 			switch (r = tls_write(c->ctx, c->sbuf + c->off, c->len)) {
498 			case -1:
499 				goto end;
500 
501 			case TLS_WANT_POLLOUT:
502 				fds->events = POLLOUT;
503 				return;
504 
505 			case TLS_WANT_POLLIN:
506 				fds->events = POLLIN;
507 				return;
508 
509 			default:
510                                 c->off += r;
511 				c->len -= r;
512 				break;
513 			}
514 		}
515 	}
516 
517 end:
518 	goodbye(fds, c);
519 }
520 
521 void
522 send_file(char *path, char *query, struct pollfd *fds, struct client *c)
523 {
524 	ssize_t ret, len;
525 
526 	if (c->fd == -1) {
527 		if (!open_file(path, query, fds, c))
528 			return;
529 		c->state = S_SENDING;
530 	}
531 
532 	len = (c->buf + c->len) - c->i;
533 
534 	while (len > 0) {
535 		switch (ret = tls_write(c->ctx, c->i, len)) {
536 		case -1:
537 			LOG(c, "tls_write: %s", tls_error(c->ctx));
538 			goodbye(fds, c);
539 			return;
540 
541 		case TLS_WANT_POLLIN:
542 			fds->events = POLLIN;
543 			return;
544 
545 		case TLS_WANT_POLLOUT:
546 			fds->events = POLLOUT;
547 			return;
548 
549 		default:
550 			c->i += ret;
551 			len -= ret;
552 			break;
553 		}
554 	}
555 
556 	goodbye(fds, c);
557 }
558 
559 void
560 send_dir(char *path, struct pollfd *fds, struct client *client)
561 {
562 	char fpath[PATHBUF];
563 	size_t len;
564 
565 	bzero(fpath, PATHBUF);
566 
567 	if (path[0] != '.')
568 		fpath[0] = '.';
569 
570 	/* this cannot fail since sizeof(fpath) > maxlen of path */
571 	strlcat(fpath, path, PATHBUF);
572 	len = strlen(fpath);
573 
574 	/* add a trailing / in case. */
575 	if (fpath[len-1] != '/') {
576 		fpath[len] = '/';
577 	}
578 
579 	strlcat(fpath, "index.gmi", sizeof(fpath));
580 
581 	send_file(fpath, NULL, fds, client);
582 }
583 
584 void
585 handle(struct pollfd *fds, struct client *client)
586 {
587 	char buf[GEMINI_URL_LEN];
588 	char *path;
589 	char *query;
590 
591 	switch (client->state) {
592 	case S_OPEN:
593 		bzero(buf, GEMINI_URL_LEN);
594 		switch (tls_read(client->ctx, buf, sizeof(buf)-1)) {
595 		case -1:
596 			LOG(client, "tls_read: %s", tls_error(client->ctx));
597 			goodbye(fds, client);
598 			return;
599 
600 		case TLS_WANT_POLLIN:
601 			fds->events = POLLIN;
602 			return;
603 
604 		case TLS_WANT_POLLOUT:
605 			fds->events = POLLOUT;
606 			return;
607 		}
608 
609 		if (!url_trim(client, buf)) {
610 			if (!start_reply(fds, client, BAD_REQUEST, "bad request"))
611 				return;
612 			goodbye(fds, client);
613 			return;
614 		}
615 
616 		if ((path = url_start_of_request(buf)) == NULL) {
617 			if (!start_reply(fds, client, BAD_REQUEST, "bad request"))
618 				return;
619 			goodbye(fds, client);
620 			return;
621 		}
622 
623 		query = adjust_path(path);
624 		LOG(client, "get %s%s%s", path,
625 		    query ? "?" : "",
626 		    query ? query : "");
627 
628 		if (path_isdir(path))
629 			send_dir(path, fds, client);
630 		else
631 			send_file(path, query, fds, client);
632 		break;
633 
634 	case S_INITIALIZING:
635 		if (!start_reply(fds, client, client->code, client->meta))
636 			return;
637 
638 		if (client->code != SUCCESS) {
639 			/* we don't need a body */
640 			goodbye(fds, client);
641 			return;
642 		}
643 
644 		client->state = S_SENDING;
645 
646 		/* fallthrough */
647 
648 	case S_SENDING:
649 		if (client->child != -1)
650 			handle_cgi(fds, client);
651 		else
652 			send_file(NULL, NULL, fds, client);
653 		break;
654 
655 	case S_CLOSING:
656 		goodbye(fds, client);
657 		break;
658 
659 	default:
660 		/* unreachable */
661 		abort();
662 	}
663 }
664 
665 void
666 mark_nonblock(int fd)
667 {
668 	int flags;
669 
670 	if ((flags = fcntl(fd, F_GETFL)) == -1)
671 		err(1, "fcntl(F_GETFL)");
672 	if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1)
673 		err(1, "fcntl(F_SETFL)");
674 }
675 
676 int
677 make_socket(int port, int family)
678 {
679 	int sock, v;
680 	struct sockaddr_in addr4;
681 	struct sockaddr_in6 addr6;
682 	struct sockaddr *addr;
683 	socklen_t len;
684 
685         switch (family) {
686 	case AF_INET:
687 		bzero(&addr4, sizeof(addr4));
688 		addr4.sin_family = family;
689 		addr4.sin_port = htons(port);
690 		addr4.sin_addr.s_addr = INADDR_ANY;
691 		addr = (struct sockaddr*)&addr4;
692 		len = sizeof(addr4);
693 		break;
694 
695 	case AF_INET6:
696 		bzero(&addr6, sizeof(addr6));
697 		addr6.sin6_family = AF_INET6;
698 		addr6.sin6_port = htons(port);
699 		addr6.sin6_addr = in6addr_any;
700 		addr = (struct sockaddr*)&addr6;
701 		len = sizeof(addr6);
702 		break;
703 
704 	default:
705 		/* unreachable */
706 		abort();
707 	}
708 
709 	if ((sock = socket(family, SOCK_STREAM, 0)) == -1)
710 		err(1, "socket");
711 
712 	v = 1;
713 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &v, sizeof(v)) == -1)
714 		err(1, "setsockopt(SO_REUSEADDR)");
715 
716 	v = 1;
717 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &v, sizeof(v)) == -1)
718 		err(1, "setsockopt(SO_REUSEPORT)");
719 
720 	mark_nonblock(sock);
721 
722 	if (bind(sock, addr, len) == -1)
723 		err(1, "bind");
724 
725 	if (listen(sock, 16) == -1)
726 		err(1, "listen");
727 
728 	return sock;
729 }
730 
731 void
732 do_accept(int sock, struct tls *ctx, struct pollfd *fds, struct client *clients)
733 {
734 	int i, fd;
735 	struct sockaddr_in addr;
736 	socklen_t len;
737 
738 	len = sizeof(addr);
739 	if ((fd = accept(sock, (struct sockaddr*)&addr, &len)) == -1) {
740 		if (errno == EWOULDBLOCK)
741 			return;
742 		err(1, "accept");
743 	}
744 
745 	mark_nonblock(fd);
746 
747 	for (i = 0; i < MAX_USERS; ++i) {
748 		if (fds[i].fd == -1) {
749 			bzero(&clients[i], sizeof(struct client));
750 			if (tls_accept_socket(ctx, &clients[i].ctx, fd) == -1)
751 				break; /* goodbye fd! */
752 
753 			fds[i].fd = fd;
754 			fds[i].events = POLLIN;
755 
756 			clients[i].state = S_OPEN;
757 			clients[i].fd = -1;
758 			clients[i].child = -1;
759 			clients[i].buf = MAP_FAILED;
760 			clients[i].af = AF_INET;
761 			clients[i].addr = addr.sin_addr;
762 
763 			return;
764 		}
765 	}
766 
767 	close(fd);
768 }
769 
770 void
771 goodbye(struct pollfd *pfd, struct client *c)
772 {
773 	ssize_t ret;
774 
775 	c->state = S_CLOSING;
776 
777 	ret = tls_close(c->ctx);
778 	if (ret == TLS_WANT_POLLIN) {
779 		pfd->events = POLLIN;
780 		return;
781 	}
782 	if (ret == TLS_WANT_POLLOUT) {
783 		pfd->events = POLLOUT;
784 		return;
785 	}
786 
787 	tls_free(c->ctx);
788 	c->ctx = NULL;
789 
790 	if (c->buf != MAP_FAILED)
791 		munmap(c->buf, c->len);
792 
793 	if (c->fd != -1)
794 		close(c->fd);
795 
796 	close(pfd->fd);
797 	pfd->fd = -1;
798 }
799 
800 void
801 loop(struct tls *ctx, int sock)
802 {
803 	int i, todo;
804 	struct client clients[MAX_USERS];
805 	struct pollfd fds[MAX_USERS];
806 
807 	for (i = 0; i < MAX_USERS; ++i) {
808 		fds[i].fd = -1;
809 		fds[i].events = POLLIN;
810 		bzero(&clients[i], sizeof(struct client));
811 	}
812 
813 	fds[0].fd = sock;
814 
815 	for (;;) {
816 		if ((todo = poll(fds, MAX_USERS, INFTIM)) == -1)
817 			err(1, "poll");
818 
819 		for (i = 0; i < MAX_USERS; i++) {
820 			assert(i < MAX_USERS);
821 
822 			if (fds[i].revents == 0)
823 				continue;
824 
825 			if (fds[i].revents & (POLLERR|POLLNVAL))
826 				err(1, "bad fd %d", fds[i].fd);
827 
828 			if (fds[i].revents & POLLHUP) {
829 				/* fds[i] may be the fd of the stdin
830 				 * of a cgi script that has exited. */
831 				if (!clients[i].waiting_on_child) {
832 					goodbye(&fds[i], &clients[i]);
833 					continue;
834 				}
835 			}
836 
837 			todo--;
838 
839 			if (i == 0) { /* new client */
840 				do_accept(sock, ctx, fds, clients);
841 				continue;
842 			}
843 
844 			handle(&fds[i], &clients[i]);
845 		}
846 	}
847 }
848 
849 void
850 usage(const char *me)
851 {
852 	fprintf(stderr,
853 	    "USAGE: %s [-h] [-c cert.pem] [-d docs] [-k key.pem]\n",
854 	    me);
855 }
856 
857 int
858 main(int argc, char **argv)
859 {
860 	const char *cert = "cert.pem", *key = "key.pem";
861 	struct tls *ctx = NULL;
862 	struct tls_config *conf;
863 	int sock, ch;
864 
865 	signal(SIGPIPE, SIG_IGN);
866 	signal(SIGCHLD, SIG_IGN);
867 
868 	dir = "docs/";
869 	logfd = 2;		/* stderr */
870 	cgi = 0;
871 
872 	while ((ch = getopt(argc, argv, "c:d:hk:l:x")) != -1) {
873 		switch (ch) {
874 		case 'c':
875 			cert = optarg;
876 			break;
877 
878 		case 'd':
879 			dir = optarg;
880 			break;
881 
882 		case 'h':
883 			usage(*argv);
884 			return 0;
885 
886 		case 'k':
887 			key = optarg;
888 			break;
889 
890 		case 'l':
891 			/* open log file or create it with 644 */
892 			if ((logfd = open(optarg, O_WRONLY | O_CREAT | O_CLOEXEC,
893 					S_IRUSR | S_IWUSR | S_IRGRP | S_IWOTH)) == -1)
894 				err(1, "%s", optarg);
895 			break;
896 
897 		case 'x':
898 			cgi = 1;
899 			break;
900 
901 		default:
902 			usage(*argv);
903 			return 1;
904 		}
905 	}
906 
907 	if ((conf = tls_config_new()) == NULL)
908 		err(1, "tls_config_new");
909 
910 	if (tls_config_set_protocols(conf,
911 	    TLS_PROTOCOL_TLSv1_2 | TLS_PROTOCOL_TLSv1_3) == -1)
912 		err(1, "tls_config_set_protocols");
913 
914 	if (tls_config_set_cert_file(conf, cert) == -1)
915 		err(1, "tls_config_set_cert_file: %s", cert);
916 
917 	if (tls_config_set_key_file(conf, key) == -1)
918 		err(1, "tls_config_set_key_file: %s", key);
919 
920 	if ((ctx = tls_server()) == NULL)
921 		err(1, "tls_server");
922 
923 	if (tls_configure(ctx, conf) == -1)
924 		errx(1, "tls_configure: %s", tls_error(ctx));
925 
926 	sock = make_socket(1965, AF_INET);
927 
928 	if ((dirfd = open(dir, O_RDONLY | O_DIRECTORY)) == -1)
929 		err(1, "open: %s", dir);
930 
931 	if (unveil(dir, cgi ? "rx" : "r") == -1)
932 		err(1, "unveil");
933 
934 	if (pledge(cgi ? "stdio rpath inet proc exec" : "stdio rpath inet", NULL) == -1)
935 		err(1, "pledge");
936 
937 	loop(ctx, sock);
938 
939 	close(sock);
940 	tls_free(ctx);
941 	tls_config_free(conf);
942 }