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 <assert.h>
22 #include <err.h>
23 #include <errno.h>
24 #include <fcntl.h>
25 #include <limits.h>
26 #include <signal.h>
27 #include <string.h>
28 
29 #include "gmid.h"
30 
31 #define LOG(priority, c, fmt, ...)					\
32 	do {								\
33 		char buf[INET_ADDRSTRLEN];				\
34 		if (inet_ntop((c)->af, &(c)->addr,			\
35 		    buf, sizeof(buf)) == NULL)				\
36 			FATAL("inet_ntop: %s", strerror(errno));	\
37 		if (foreground)						\
38 			fprintf(stderr,					\
39 			    "%s " fmt "\n", buf, __VA_ARGS__);		\
40 		else							\
41 			syslog((priority) | LOG_DAEMON,			\
42 			    "%s " fmt, buf, __VA_ARGS__);		\
43 	} while (0)
44 
45 #define LOGE(c, fmt, ...) LOG(LOG_ERR,    c, fmt, __VA_ARGS__)
46 #define LOGN(c, fmt, ...) LOG(LOG_NOTICE, c, fmt, __VA_ARGS__)
47 #define LOGI(c, fmt, ...) LOG(LOG_INFO,   c, fmt, __VA_ARGS__)
48 #define LOGD(c, fmt, ...) LOG(LOG_DEBUG,  c, fmt, __VA_ARGS__)
49 
50 #define FATAL(fmt, ...)							\
51 	do {								\
52 		if (foreground)						\
53 			fprintf(stderr, fmt "\n", __VA_ARGS__);		\
54 		else							\
55 			syslog(LOG_DAEMON | LOG_CRIT,			\
56 			    fmt, __VA_ARGS__);				\
57 		exit(1);						\
58 	} while (0)
59 
60 const char *dir, *cgi;
61 int dirfd;
62 int port;
63 int foreground;
64 int connected_clients;
65 
66 struct etm {			/* file extension to mime */
67 	const char	*mime;
68 	const char	*ext;
69 } filetypes[] = {
70 	{"application/pdf",	"pdf"},
71 
72 	{"image/gif",		"gif"},
73 	{"image/jpeg",		"jpg"},
74 	{"image/jpeg",		"jpeg"},
75 	{"image/png",		"png"},
76 	{"image/svg+xml",	"svg"},
77 
78 	{"text/gemini",		"gemini"},
79 	{"text/gemini",		"gmi"},
80 	{"text/markdown",	"markdown"},
81 	{"text/markdown",	"md"},
82 	{"text/plain",		"txt"},
83 	{"text/xml",		"xml"},
84 
85 	{NULL, NULL}
86 };
87 
88 static inline void
89 safe_setenv(const char *name, const char *val)
90 {
91 	if (val == NULL)
92 		val = "";
93 	setenv(name, val, 1);
94 }
95 
96 void
97 sig_handler(int sig)
98 {
99 	(void)sig;
100 }
101 
102 int
103 starts_with(const char *str, const char *prefix)
104 {
105 	size_t i;
106 
107 	for (i = 0; prefix[i] != '\0'; ++i)
108 		if (str[i] != prefix[i])
109 			return 0;
110 	return 1;
111 }
112 
113 int
114 start_reply(struct pollfd *pfd, struct client *client, int code, const char *reason)
115 {
116 	char buf[1030] = {0}; 	/* status + ' ' + max reply len + \r\n\0 */
117 	int len;
118 	int ret;
119 
120 	client->code = code;
121 	client->meta = reason;
122 	client->state = S_INITIALIZING;
123 
124 	len = snprintf(buf, sizeof(buf), "%d %s\r\n", code, reason);
125 	assert(len < (int)sizeof(buf));
126 	ret = tls_write(client->ctx, buf, len);
127 	if (ret == TLS_WANT_POLLIN) {
128 		pfd->events = POLLIN;
129 		return 0;
130 	}
131 
132 	if (ret == TLS_WANT_POLLOUT) {
133 		pfd->events = POLLOUT;
134 		return 0;
135 	}
136 
137 	return 1;
138 }
139 
140 ssize_t
141 filesize(int fd)
142 {
143 	ssize_t len;
144 
145 	if ((len = lseek(fd, 0, SEEK_END)) == -1)
146 		return -1;
147 	if (lseek(fd, 0, SEEK_SET) == -1)
148 		return -1;
149 	return len;
150 }
151 
152 const char *
153 path_ext(const char *path)
154 {
155 	const char *end;
156 
157 	end = path + strlen(path)-1; /* the last byte before the NUL */
158 	for (; end != path; --end) {
159 		if (*end == '.')
160 			return end+1;
161 		if (*end == '/')
162 			break;
163 	}
164 
165 	return NULL;
166 }
167 
168 const char *
169 mime(const char *path)
170 {
171 	const char *ext, *def = "application/octet-stream";
172 	struct etm *t;
173 
174 	if ((ext = path_ext(path)) == NULL)
175 		return def;
176 
177 	for (t = filetypes; t->mime != NULL; ++t)
178 		if (!strcmp(ext, t->ext))
179 			return t->mime;
180 
181 	return def;
182 }
183 
184 int
185 check_path(struct client *c, const char *path, int *fd)
186 {
187 	struct stat sb;
188 
189 	assert(path != NULL);
190 	if ((*fd = openat(dirfd, *path ? path : ".",
191 		    O_RDONLY | O_NOFOLLOW | O_CLOEXEC)) == -1) {
192 		return FILE_MISSING;
193 	}
194 
195 	if (fstat(*fd, &sb) == -1) {
196 		LOGN(c, "failed stat for %s: %s", path, strerror(errno));
197 		return FILE_MISSING;
198 	}
199 
200 	if (S_ISDIR(sb.st_mode))
201 		return FILE_DIRECTORY;
202 
203 	if (sb.st_mode & S_IXUSR)
204 		return FILE_EXECUTABLE;
205 
206 	return FILE_EXISTS;
207 }
208 
209 /*
210  * the inverse of this algorithm, i.e. starting from the start of the
211  * path + strlen(cgi), and checking if each component, should be
212  * faster.  But it's tedious to write.  This does the opposite: starts
213  * from the end and strip one component at a time, until either an
214  * executable is found or we emptied the path.
215  */
216 int
217 check_for_cgi(char *path, char *query, struct pollfd *fds, struct client *c)
218 {
219 	char *end;
220 	end = strchr(path, '\0');
221 
222 	/* NB: assume CGI is enabled and path matches cgi */
223 
224 	while (end > path) {
225 		/* go up one level.  UNIX paths are simple and POSIX
226 		 * dirname, with its ambiguities on if the given path
227 		 * is changed or not, gives me headaches. */
228 		while (*end != '/')
229 			end--;
230 		*end = '\0';
231 
232 		switch (check_path(c, path, &c->fd)) {
233 		case FILE_EXECUTABLE:
234 			return start_cgi(path, end+1, query, fds,c);
235 		case FILE_MISSING:
236 			break;
237 		default:
238 			goto err;
239 		}
240 
241 		*end = '/';
242 		end--;
243 	}
244 
245 err:
246 	if (!start_reply(fds, c, NOT_FOUND, "not found"))
247 		return 0;
248 	goodbye(fds, c);
249 	return 0;
250 }
251 
252 
253 int
254 open_file(char *fpath, char *query, struct pollfd *fds, struct client *c)
255 {
256 	switch (check_path(c, fpath, &c->fd)) {
257 	case FILE_EXECUTABLE:
258 		if (cgi != NULL && starts_with(fpath, cgi))
259 			return start_cgi(fpath, "", query, fds, c);
260 
261 		/* fallthrough */
262 
263 	case FILE_EXISTS:
264 		if ((c->len = filesize(c->fd)) == -1) {
265 			LOGE(c, "failed to get file size for %s", fpath);
266 			goodbye(fds, c);
267 			return 0;
268 		}
269 
270 		if ((c->buf = mmap(NULL, c->len, PROT_READ, MAP_PRIVATE,
271 			    c->fd, 0)) == MAP_FAILED) {
272 			warn("mmap: %s", fpath);
273 			goodbye(fds, c);
274 			return 0;
275 		}
276 		c->i = c->buf;
277 		return start_reply(fds, c, SUCCESS, mime(fpath));
278 
279 	case FILE_DIRECTORY:
280 		LOGD(c, "%s is a directory, trying %s/index.gmi", fpath, fpath);
281 		close(c->fd);
282 		c->fd = -1;
283 		send_dir(fpath, fds, c);
284 		return 0;
285 
286 	case FILE_MISSING:
287 		if (cgi != NULL && starts_with(fpath, cgi))
288 			return check_for_cgi(fpath, query, fds, c);
289 
290 		if (!start_reply(fds, c, NOT_FOUND, "not found"))
291 			return 0;
292 		goodbye(fds, c);
293 		return 0;
294 
295 	default:
296 		/* unreachable */
297 		abort();
298 	}
299 }
300 
301 int
302 start_cgi(const char *spath, const char *relpath, const char *query,
303     struct pollfd *fds, struct client *c)
304 {
305 	pid_t pid;
306 	int p[2]; 		/* read end, write end */
307 
308 	if (pipe(p) == -1)
309 		goto err;
310 
311 	switch (pid = fork()) {
312 	case -1:
313 		goto err;
314 
315 	case 0: { 		/* child */
316 		char *ex, *requri, *portno;
317 		char addr[INET_ADDRSTRLEN];
318 		char *argv[] = { NULL, NULL, NULL };
319 
320 		close(p[0]);
321 		if (dup2(p[1], 1) == -1)
322 			goto childerr;
323 
324 		if (inet_ntop(c->af, &c->addr, addr, sizeof(addr)) == NULL)
325 			goto childerr;
326 
327 		if (asprintf(&portno, "%d", port) == -1)
328 			goto childerr;
329 
330 		if (asprintf(&ex, "%s/%s", dir, spath) == -1)
331 			goto childerr;
332 
333 		if (asprintf(&requri, "%s%s%s", spath,
334 		    *relpath == '\0' ? "" : "/",
335 		    relpath) == -1)
336 			goto childerr;
337 
338 		argv[0] = argv[1] = ex;
339 
340 		/* fix the env */
341 		safe_setenv("GATEWAY_INTERFACE", "CGI/1.1");
342 		safe_setenv("SERVER_SOFTWARE", "gmid");
343 		safe_setenv("SERVER_PORT", portno);
344 		/* setenv("SERVER_NAME", "", 1); */
345 		safe_setenv("SCRIPT_NAME", spath);
346 		safe_setenv("SCRIPT_EXECUTABLE", ex);
347 		safe_setenv("REQUEST_URI", requri);
348 		safe_setenv("REQUEST_RELATIVE", relpath);
349 		safe_setenv("QUERY_STRING", query);
350 		safe_setenv("REMOTE_HOST", addr);
351 		safe_setenv("REMOTE_ADDR", addr);
352 		safe_setenv("DOCUMENT_ROOT", dir);
353 
354 		if (tls_peer_cert_provided(c->ctx)) {
355 			safe_setenv("AUTH_TYPE", "Certificate");
356 			safe_setenv("REMOTE_USER", tls_peer_cert_subject(c->ctx));
357 			safe_setenv("TLS_CLIENT_ISSUER", tls_peer_cert_issuer(c->ctx));
358 			safe_setenv("TLS_CLIENT_HASH", tls_peer_cert_hash(c->ctx));
359 		}
360 
361 		execvp(ex, argv);
362 		goto childerr;
363 	}
364 
365 	default:		/* parent */
366 		close(p[1]);
367 		close(c->fd);
368 		c->fd = p[0];
369 		c->child = pid;
370 		mark_nonblock(c->fd);
371 		c->state = S_SENDING;
372 		handle_cgi(fds, c);
373 		return 0;
374 	}
375 
376 err:
377 	if (!start_reply(fds, c, TEMP_FAILURE, "internal server error"))
378 		return 0;
379 	goodbye(fds, c);
380 	return 0;
381 
382 childerr:
383 	dprintf(p[1], "%d internal server error\r\n", TEMP_FAILURE);
384 	close(p[1]);
385 	_exit(1);
386 }
387 
388 void
389 cgi_poll_on_child(struct pollfd *fds, struct client *c)
390 {
391 	int fd;
392 
393 	if (c->waiting_on_child)
394 		return;
395 	c->waiting_on_child = 1;
396 
397 	fds->events = POLLIN;
398 
399 	fd = fds->fd;
400 	fds->fd = c->fd;
401 	c->fd = fd;
402 }
403 
404 void
405 cgi_poll_on_client(struct pollfd *fds, struct client *c)
406 {
407 	int fd;
408 
409 	if (!c->waiting_on_child)
410 		return;
411 	c->waiting_on_child = 0;
412 
413 	fd = fds->fd;
414 	fds->fd = c->fd;
415 	c->fd = fd;
416 }
417 
418 void
419 handle_cgi(struct pollfd *fds, struct client *c)
420 {
421 	ssize_t r;
422 
423 	/* ensure c->fd is the child and fds->fd the client */
424 	cgi_poll_on_client(fds, c);
425 
426 	while (1) {
427 		if (c->len == 0) {
428 			if ((r = read(c->fd, c->sbuf, sizeof(c->sbuf))) == 0)
429 				goto end;
430 			if (r == -1) {
431 				if (errno == EAGAIN || errno == EWOULDBLOCK) {
432 					cgi_poll_on_child(fds, c);
433 					return;
434 				}
435                                 goto end;
436 			}
437 			c->len = r;
438 			c->off = 0;
439 		}
440 
441 		while (c->len > 0) {
442 			switch (r = tls_write(c->ctx, c->sbuf + c->off, c->len)) {
443 			case -1:
444 				goto end;
445 
446 			case TLS_WANT_POLLOUT:
447 				fds->events = POLLOUT;
448 				return;
449 
450 			case TLS_WANT_POLLIN:
451 				fds->events = POLLIN;
452 				return;
453 
454 			default:
455                                 c->off += r;
456 				c->len -= r;
457 				break;
458 			}
459 		}
460 	}
461 
462 end:
463 	goodbye(fds, c);
464 }
465 
466 void
467 send_file(char *path, char *query, struct pollfd *fds, struct client *c)
468 {
469 	ssize_t ret, len;
470 
471 	if (c->fd == -1) {
472 		if (!open_file(path, query, fds, c))
473 			return;
474 		c->state = S_SENDING;
475 	}
476 
477 	len = (c->buf + c->len) - c->i;
478 
479 	while (len > 0) {
480 		switch (ret = tls_write(c->ctx, c->i, len)) {
481 		case -1:
482 			LOGE(c, "tls_write: %s", tls_error(c->ctx));
483 			goodbye(fds, c);
484 			return;
485 
486 		case TLS_WANT_POLLIN:
487 			fds->events = POLLIN;
488 			return;
489 
490 		case TLS_WANT_POLLOUT:
491 			fds->events = POLLOUT;
492 			return;
493 
494 		default:
495 			c->i += ret;
496 			len -= ret;
497 			break;
498 		}
499 	}
500 
501 	goodbye(fds, c);
502 }
503 
504 void
505 send_dir(char *path, struct pollfd *fds, struct client *client)
506 {
507 	char fpath[PATHBUF];
508 	size_t len;
509 
510 	bzero(fpath, PATHBUF);
511 
512 	if (path[0] != '.')
513 		fpath[0] = '.';
514 
515 	/* this cannot fail since sizeof(fpath) > maxlen of path */
516 	strlcat(fpath, path, PATHBUF);
517 	len = strlen(fpath);
518 
519 	/* add a trailing / in case. */
520 	if (fpath[len-1] != '/') {
521 		fpath[len] = '/';
522 	}
523 
524 	strlcat(fpath, "index.gmi", sizeof(fpath));
525 
526 	send_file(fpath, NULL, fds, client);
527 }
528 
529 void
530 handle(struct pollfd *fds, struct client *client)
531 {
532 	char buf[GEMINI_URL_LEN];
533 	const char *parse_err;
534 	struct uri uri;
535 
536 	switch (client->state) {
537 	case S_OPEN:
538 		bzero(buf, GEMINI_URL_LEN);
539 		switch (tls_read(client->ctx, buf, sizeof(buf)-1)) {
540 		case -1:
541 			LOGE(client, "tls_read: %s", tls_error(client->ctx));
542 			goodbye(fds, client);
543 			return;
544 
545 		case TLS_WANT_POLLIN:
546 			fds->events = POLLIN;
547 			return;
548 
549 		case TLS_WANT_POLLOUT:
550 			fds->events = POLLOUT;
551 			return;
552 		}
553 
554 		parse_err = "invalid request";
555 		if (!trim_req_uri(buf) || !parse_uri(buf, &uri, &parse_err)) {
556 			if (!start_reply(fds, client, BAD_REQUEST, parse_err))
557 				return;
558 			goodbye(fds, client);
559 			return;
560 		}
561 
562 		LOGI(client, "GET %s%s%s",
563 		    *uri.path ? uri.path : "/",
564 		    *uri.query ? "?" : "",
565 		    *uri.query ? uri.query : "");
566 
567 		send_file(uri.path, uri.query, fds, client);
568 		break;
569 
570 	case S_INITIALIZING:
571 		if (!start_reply(fds, client, client->code, client->meta))
572 			return;
573 
574 		if (client->code != SUCCESS) {
575 			/* we don't need a body */
576 			goodbye(fds, client);
577 			return;
578 		}
579 
580 		client->state = S_SENDING;
581 
582 		/* fallthrough */
583 
584 	case S_SENDING:
585 		if (client->child != -1)
586 			handle_cgi(fds, client);
587 		else
588 			send_file(NULL, NULL, fds, client);
589 		break;
590 
591 	case S_CLOSING:
592 		goodbye(fds, client);
593 		break;
594 
595 	default:
596 		/* unreachable */
597 		abort();
598 	}
599 }
600 
601 void
602 mark_nonblock(int fd)
603 {
604 	int flags;
605 
606 	if ((flags = fcntl(fd, F_GETFL)) == -1)
607 		FATAL("fcntl(F_GETFL): %s", strerror(errno));
608 	if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1)
609 		FATAL("fcntl(F_SETFL): %s", strerror(errno));
610 }
611 
612 int
613 make_socket(int port, int family)
614 {
615 	int sock, v;
616 	struct sockaddr_in addr4;
617 	struct sockaddr_in6 addr6;
618 	struct sockaddr *addr;
619 	socklen_t len;
620 
621         switch (family) {
622 	case AF_INET:
623 		bzero(&addr4, sizeof(addr4));
624 		addr4.sin_family = family;
625 		addr4.sin_port = htons(port);
626 		addr4.sin_addr.s_addr = INADDR_ANY;
627 		addr = (struct sockaddr*)&addr4;
628 		len = sizeof(addr4);
629 		break;
630 
631 	case AF_INET6:
632 		bzero(&addr6, sizeof(addr6));
633 		addr6.sin6_family = AF_INET6;
634 		addr6.sin6_port = htons(port);
635 		addr6.sin6_addr = in6addr_any;
636 		addr = (struct sockaddr*)&addr6;
637 		len = sizeof(addr6);
638 		break;
639 
640 	default:
641 		/* unreachable */
642 		abort();
643 	}
644 
645 	if ((sock = socket(family, SOCK_STREAM, 0)) == -1)
646 		FATAL("socket: %s", strerror(errno));
647 
648 	v = 1;
649 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &v, sizeof(v)) == -1)
650 		FATAL("setsockopt(SO_REUSEADDR): %s", strerror(errno));
651 
652 	v = 1;
653 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &v, sizeof(v)) == -1)
654 		FATAL("setsockopt(SO_REUSEPORT): %s", strerror(errno));
655 
656 	mark_nonblock(sock);
657 
658 	if (bind(sock, addr, len) == -1)
659 		FATAL("bind: %s", strerror(errno));
660 
661 	if (listen(sock, 16) == -1)
662 		FATAL("listen: %s", strerror(errno));
663 
664 	return sock;
665 }
666 
667 void
668 do_accept(int sock, struct tls *ctx, struct pollfd *fds, struct client *clients)
669 {
670 	int i, fd;
671 	struct sockaddr_in addr;
672 	socklen_t len;
673 
674 	len = sizeof(addr);
675 	if ((fd = accept(sock, (struct sockaddr*)&addr, &len)) == -1) {
676 		if (errno == EWOULDBLOCK)
677 			return;
678 		FATAL("accept: %s", strerror(errno));
679 	}
680 
681 	mark_nonblock(fd);
682 
683 	for (i = 0; i < MAX_USERS; ++i) {
684 		if (fds[i].fd == -1) {
685 			bzero(&clients[i], sizeof(struct client));
686 			if (tls_accept_socket(ctx, &clients[i].ctx, fd) == -1)
687 				break; /* goodbye fd! */
688 
689 			fds[i].fd = fd;
690 			fds[i].events = POLLIN;
691 
692 			clients[i].state = S_OPEN;
693 			clients[i].fd = -1;
694 			clients[i].child = -1;
695 			clients[i].buf = MAP_FAILED;
696 			clients[i].af = AF_INET;
697 			clients[i].addr = addr.sin_addr;
698 
699 			connected_clients++;
700 			return;
701 		}
702 	}
703 
704 	close(fd);
705 }
706 
707 void
708 goodbye(struct pollfd *pfd, struct client *c)
709 {
710 	ssize_t ret;
711 
712 	c->state = S_CLOSING;
713 
714 	ret = tls_close(c->ctx);
715 	if (ret == TLS_WANT_POLLIN) {
716 		pfd->events = POLLIN;
717 		return;
718 	}
719 	if (ret == TLS_WANT_POLLOUT) {
720 		pfd->events = POLLOUT;
721 		return;
722 	}
723 
724 	connected_clients--;
725 
726 	tls_free(c->ctx);
727 	c->ctx = NULL;
728 
729 	if (c->buf != MAP_FAILED)
730 		munmap(c->buf, c->len);
731 
732 	if (c->fd != -1)
733 		close(c->fd);
734 
735 	close(pfd->fd);
736 	pfd->fd = -1;
737 }
738 
739 void
740 loop(struct tls *ctx, int sock)
741 {
742 	int i;
743 	struct client clients[MAX_USERS];
744 	struct pollfd fds[MAX_USERS];
745 
746 	for (i = 0; i < MAX_USERS; ++i) {
747 		fds[i].fd = -1;
748 		fds[i].events = POLLIN;
749 		bzero(&clients[i], sizeof(struct client));
750 	}
751 
752 	fds[0].fd = sock;
753 
754 	for (;;) {
755 		if (poll(fds, MAX_USERS, INFTIM) == -1) {
756 			if (errno == EINTR) {
757                                 warnx("connected clients: %d",
758 				    connected_clients);
759 				continue;
760 			}
761 			FATAL("poll: %s", strerror(errno));
762 		}
763 
764 		for (i = 0; i < MAX_USERS; i++) {
765 			if (fds[i].revents == 0)
766 				continue;
767 
768 			if (fds[i].revents & (POLLERR|POLLNVAL))
769 				FATAL("bad fd %d: %s", fds[i].fd,
770 				    strerror(errno));
771 
772 			if (fds[i].revents & POLLHUP) {
773 				/* fds[i] may be the fd of the stdin
774 				 * of a cgi script that has exited. */
775 				if (!clients[i].waiting_on_child) {
776 					goodbye(&fds[i], &clients[i]);
777 					continue;
778 				}
779 			}
780 
781 			if (i == 0) { /* new client */
782 				do_accept(sock, ctx, fds, clients);
783 				continue;
784 			}
785 
786 			handle(&fds[i], &clients[i]);
787 		}
788 	}
789 }
790 
791 char *
792 absolutify_path(const char *path)
793 {
794 	char *wd, *r;
795 
796 	if (*path == '/')
797 		return strdup(path);
798 
799 	wd = getwd(NULL);
800 	if (asprintf(&r, "%s/%s", wd, path) == -1)
801 		err(1, "asprintf");
802 	free(wd);
803 	return r;
804 }
805 
806 void
807 usage(const char *me)
808 {
809 	fprintf(stderr,
810 	    "USAGE: %s [-h] [-c cert.pem] [-d docs] [-k key.pem] "
811 	    "[-l logfile] [-p port] [-x cgi-bin]\n",
812 	    me);
813 }
814 
815 int
816 main(int argc, char **argv)
817 {
818 	const char *cert = "cert.pem", *key = "key.pem";
819 	struct tls *ctx = NULL;
820 	struct tls_config *conf;
821 	int sock, ch;
822 	connected_clients = 0;
823 
824 	if ((dir = absolutify_path("docs")) == NULL)
825 		err(1, "absolutify_path");
826 
827 	cgi = NULL;
828 	port = 1965;
829 	foreground = 0;
830 
831 	while ((ch = getopt(argc, argv, "c:d:fhk:p:x:")) != -1) {
832 		switch (ch) {
833 		case 'c':
834 			cert = optarg;
835 			break;
836 
837 		case 'd':
838 			free((char*)dir);
839 			if ((dir = absolutify_path(optarg)) == NULL)
840 				err(1, "absolutify_path");
841 			break;
842 
843 		case 'f':
844 			foreground = 1;
845 			break;
846 
847 		case 'h':
848 			usage(*argv);
849 			return 0;
850 
851 		case 'k':
852 			key = optarg;
853 			break;
854 
855 		case 'p': {
856 			char *ep;
857 			long lval;
858 
859 			errno = 0;
860 			lval = strtol(optarg, &ep, 10);
861 			if (optarg[0] == '\0' || *ep != '\0')
862 				err(1, "not a number: %s", optarg);
863 			if (lval < 0 || lval > UINT16_MAX)
864 				err(1, "port number out of range: %s", optarg);
865 			port = lval;
866 			break;
867 		}
868 
869 		case 'x':
870 			cgi = optarg;
871 			break;
872 
873 		default:
874 			usage(*argv);
875 			return 1;
876 		}
877 	}
878 
879 	signal(SIGPIPE, SIG_IGN);
880 	signal(SIGCHLD, SIG_IGN);
881 
882 #ifdef SIGINFO
883 	signal(SIGINFO, sig_handler);
884 #endif
885 	signal(SIGUSR2, sig_handler);
886 
887 	if (!foreground)
888 		signal(SIGHUP, SIG_IGN);
889 
890 	if ((conf = tls_config_new()) == NULL)
891 		err(1, "tls_config_new");
892 
893 	/* optionally accept client certs, but don't try to verify them */
894 	tls_config_verify_client_optional(conf);
895 	tls_config_insecure_noverifycert(conf);
896 
897 	if (tls_config_set_protocols(conf,
898 	    TLS_PROTOCOL_TLSv1_2 | TLS_PROTOCOL_TLSv1_3) == -1)
899 		err(1, "tls_config_set_protocols");
900 
901 	if (tls_config_set_cert_file(conf, cert) == -1)
902 		err(1, "tls_config_set_cert_file: %s", cert);
903 
904 	if (tls_config_set_key_file(conf, key) == -1)
905 		err(1, "tls_config_set_key_file: %s", key);
906 
907 	if ((ctx = tls_server()) == NULL)
908 		err(1, "tls_server");
909 
910 	if (tls_configure(ctx, conf) == -1)
911 		errx(1, "tls_configure: %s", tls_error(ctx));
912 
913 	sock = make_socket(port, AF_INET);
914 
915 	if ((dirfd = open(dir, O_RDONLY | O_DIRECTORY)) == -1)
916 		err(1, "open: %s", dir);
917 
918 	if (!foreground && daemon(0, 1) == -1)
919 		exit(1);
920 
921 	if (unveil(dir, "rx") == -1)
922 		err(1, "unveil");
923 
924 	if (pledge("stdio rpath inet proc exec", NULL) == -1)
925 		err(1, "pledge");
926 
927 	/* drop proc and exec if cgi isn't enabled */
928 	if (cgi == NULL && pledge("stdio rpath inet", NULL) == -1)
929 		err(1, "pledge");
930 
931 	loop(ctx, sock);
932 
933 	close(sock);
934 	tls_free(ctx);
935 	tls_config_free(conf);
936 }