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 <stdarg.h>
28 #include <string.h>
29 
30 #include "gmid.h"
31 
32 #define LOGE(c, fmt, ...) logs(LOG_ERR,    c, fmt, __VA_ARGS__)
33 #define LOGN(c, fmt, ...) logs(LOG_NOTICE, c, fmt, __VA_ARGS__)
34 #define LOGI(c, fmt, ...) logs(LOG_INFO,   c, fmt, __VA_ARGS__)
35 #define LOGD(c, fmt, ...) logs(LOG_DEBUG,  c, fmt, __VA_ARGS__)
36 
37 const char *dir, *cgi;
38 int dirfd;
39 int port;
40 int foreground;
41 int connected_clients;
42 
43 struct etm {			/* file extension to mime */
44 	const char	*mime;
45 	const char	*ext;
46 } filetypes[] = {
47 	{"application/pdf",	"pdf"},
48 
49 	{"image/gif",		"gif"},
50 	{"image/jpeg",		"jpg"},
51 	{"image/jpeg",		"jpeg"},
52 	{"image/png",		"png"},
53 	{"image/svg+xml",	"svg"},
54 
55 	{"text/gemini",		"gemini"},
56 	{"text/gemini",		"gmi"},
57 	{"text/markdown",	"markdown"},
58 	{"text/markdown",	"md"},
59 	{"text/plain",		"txt"},
60 	{"text/xml",		"xml"},
61 
62 	{NULL, NULL}
63 };
64 
65 static inline void
66 safe_setenv(const char *name, const char *val)
67 {
68 	if (val == NULL)
69 		val = "";
70 	setenv(name, val, 1);
71 }
72 
73 __attribute__ ((format (printf, 1, 2)))
74 static inline void __dead
75 fatal(const char *fmt, ...)
76 {
77 	va_list ap;
78 
79 	va_start(ap, fmt);
80 
81 	if (foreground) {
82 		vfprintf(stderr, fmt, ap);
83 		fprintf(stderr, "\n");
84 	} else
85 		vsyslog(LOG_DAEMON | LOG_CRIT, fmt, ap);
86 
87 	va_end(ap);
88 	exit(1);
89 }
90 
91 __attribute__ ((format (printf, 3, 4)))
92 static inline void
93 logs(int priority, struct client *c, const char *fmt, ...)
94 {
95 	char buf[INET_ADDRSTRLEN];
96 	va_list ap;
97 
98 	va_start(ap, fmt);
99 	priority |= LOG_DAEMON;
100 
101 	if (inet_ntop(c->af, &c->addr, buf, sizeof(buf)) == NULL)
102 		fatal("inet_ntop: %s", strerror(errno));
103 
104 	if (foreground) {
105 		vfprintf(stderr, fmt, ap);
106 		fprintf(stderr, "\n");
107 	} else
108 		vsyslog(priority, fmt, ap);
109 
110 	va_end(ap);
111 }
112 
113 void
114 sig_handler(int sig)
115 {
116 	(void)sig;
117 }
118 
119 int
120 starts_with(const char *str, const char *prefix)
121 {
122 	size_t i;
123 
124 	for (i = 0; prefix[i] != '\0'; ++i)
125 		if (str[i] != prefix[i])
126 			return 0;
127 	return 1;
128 }
129 
130 int
131 start_reply(struct pollfd *pfd, struct client *client, int code, const char *reason)
132 {
133 	char buf[1030] = {0}; 	/* status + ' ' + max reply len + \r\n\0 */
134 	int len;
135 	int ret;
136 
137 	client->code = code;
138 	client->meta = reason;
139 	client->state = S_INITIALIZING;
140 
141 	len = snprintf(buf, sizeof(buf), "%d %s\r\n", code, reason);
142 	assert(len < (int)sizeof(buf));
143 	ret = tls_write(client->ctx, buf, len);
144 	if (ret == TLS_WANT_POLLIN) {
145 		pfd->events = POLLIN;
146 		return 0;
147 	}
148 
149 	if (ret == TLS_WANT_POLLOUT) {
150 		pfd->events = POLLOUT;
151 		return 0;
152 	}
153 
154 	return 1;
155 }
156 
157 ssize_t
158 filesize(int fd)
159 {
160 	ssize_t len;
161 
162 	if ((len = lseek(fd, 0, SEEK_END)) == -1)
163 		return -1;
164 	if (lseek(fd, 0, SEEK_SET) == -1)
165 		return -1;
166 	return len;
167 }
168 
169 const char *
170 path_ext(const char *path)
171 {
172 	const char *end;
173 
174 	end = path + strlen(path)-1; /* the last byte before the NUL */
175 	for (; end != path; --end) {
176 		if (*end == '.')
177 			return end+1;
178 		if (*end == '/')
179 			break;
180 	}
181 
182 	return NULL;
183 }
184 
185 const char *
186 mime(const char *path)
187 {
188 	const char *ext, *def = "application/octet-stream";
189 	struct etm *t;
190 
191 	if ((ext = path_ext(path)) == NULL)
192 		return def;
193 
194 	for (t = filetypes; t->mime != NULL; ++t)
195 		if (!strcmp(ext, t->ext))
196 			return t->mime;
197 
198 	return def;
199 }
200 
201 int
202 check_path(struct client *c, const char *path, int *fd)
203 {
204 	struct stat sb;
205 
206 	assert(path != NULL);
207 	if ((*fd = openat(dirfd, *path ? path : ".",
208 		    O_RDONLY | O_NOFOLLOW | O_CLOEXEC)) == -1) {
209 		return FILE_MISSING;
210 	}
211 
212 	if (fstat(*fd, &sb) == -1) {
213 		LOGN(c, "failed stat for %s: %s", path, strerror(errno));
214 		return FILE_MISSING;
215 	}
216 
217 	if (S_ISDIR(sb.st_mode))
218 		return FILE_DIRECTORY;
219 
220 	if (sb.st_mode & S_IXUSR)
221 		return FILE_EXECUTABLE;
222 
223 	return FILE_EXISTS;
224 }
225 
226 /*
227  * the inverse of this algorithm, i.e. starting from the start of the
228  * path + strlen(cgi), and checking if each component, should be
229  * faster.  But it's tedious to write.  This does the opposite: starts
230  * from the end and strip one component at a time, until either an
231  * executable is found or we emptied the path.
232  */
233 int
234 check_for_cgi(char *path, char *query, struct pollfd *fds, struct client *c)
235 {
236 	char *end;
237 	end = strchr(path, '\0');
238 
239 	/* NB: assume CGI is enabled and path matches cgi */
240 
241 	while (end > path) {
242 		/* go up one level.  UNIX paths are simple and POSIX
243 		 * dirname, with its ambiguities on if the given path
244 		 * is changed or not, gives me headaches. */
245 		while (*end != '/')
246 			end--;
247 		*end = '\0';
248 
249 		switch (check_path(c, path, &c->fd)) {
250 		case FILE_EXECUTABLE:
251 			return start_cgi(path, end+1, query, fds,c);
252 		case FILE_MISSING:
253 			break;
254 		default:
255 			goto err;
256 		}
257 
258 		*end = '/';
259 		end--;
260 	}
261 
262 err:
263 	if (!start_reply(fds, c, NOT_FOUND, "not found"))
264 		return 0;
265 	goodbye(fds, c);
266 	return 0;
267 }
268 
269 
270 int
271 open_file(char *fpath, char *query, struct pollfd *fds, struct client *c)
272 {
273 	switch (check_path(c, fpath, &c->fd)) {
274 	case FILE_EXECUTABLE:
275 		if (cgi != NULL && starts_with(fpath, cgi))
276 			return start_cgi(fpath, "", query, fds, c);
277 
278 		/* fallthrough */
279 
280 	case FILE_EXISTS:
281 		if ((c->len = filesize(c->fd)) == -1) {
282 			LOGE(c, "failed to get file size for %s", fpath);
283 			goodbye(fds, c);
284 			return 0;
285 		}
286 
287 		if ((c->buf = mmap(NULL, c->len, PROT_READ, MAP_PRIVATE,
288 			    c->fd, 0)) == MAP_FAILED) {
289 			warn("mmap: %s", fpath);
290 			goodbye(fds, c);
291 			return 0;
292 		}
293 		c->i = c->buf;
294 		return start_reply(fds, c, SUCCESS, mime(fpath));
295 
296 	case FILE_DIRECTORY:
297 		LOGD(c, "%s is a directory, trying %s/index.gmi", fpath, fpath);
298 		close(c->fd);
299 		c->fd = -1;
300 		send_dir(fpath, fds, c);
301 		return 0;
302 
303 	case FILE_MISSING:
304 		if (cgi != NULL && starts_with(fpath, cgi))
305 			return check_for_cgi(fpath, query, fds, c);
306 
307 		if (!start_reply(fds, c, NOT_FOUND, "not found"))
308 			return 0;
309 		goodbye(fds, c);
310 		return 0;
311 
312 	default:
313 		/* unreachable */
314 		abort();
315 	}
316 }
317 
318 int
319 start_cgi(const char *spath, const char *relpath, const char *query,
320     struct pollfd *fds, struct client *c)
321 {
322 	pid_t pid;
323 	int p[2]; 		/* read end, write end */
324 
325 	if (pipe(p) == -1)
326 		goto err;
327 
328 	switch (pid = fork()) {
329 	case -1:
330 		goto err;
331 
332 	case 0: { 		/* child */
333 		char *ex, *requri, *portno;
334 		char addr[INET_ADDRSTRLEN];
335 		char *argv[] = { NULL, NULL, NULL };
336 
337 		close(p[0]);
338 		if (dup2(p[1], 1) == -1)
339 			goto childerr;
340 
341 		if (inet_ntop(c->af, &c->addr, addr, sizeof(addr)) == NULL)
342 			goto childerr;
343 
344 		if (asprintf(&portno, "%d", port) == -1)
345 			goto childerr;
346 
347 		if (asprintf(&ex, "%s/%s", dir, spath) == -1)
348 			goto childerr;
349 
350 		if (asprintf(&requri, "%s%s%s", spath,
351 		    *relpath == '\0' ? "" : "/",
352 		    relpath) == -1)
353 			goto childerr;
354 
355 		argv[0] = argv[1] = ex;
356 
357 		/* fix the env */
358 		safe_setenv("GATEWAY_INTERFACE", "CGI/1.1");
359 		safe_setenv("SERVER_SOFTWARE", "gmid");
360 		safe_setenv("SERVER_PORT", portno);
361 		/* setenv("SERVER_NAME", "", 1); */
362 		safe_setenv("SCRIPT_NAME", spath);
363 		safe_setenv("SCRIPT_EXECUTABLE", ex);
364 		safe_setenv("REQUEST_URI", requri);
365 		safe_setenv("REQUEST_RELATIVE", relpath);
366 		safe_setenv("QUERY_STRING", query);
367 		safe_setenv("REMOTE_HOST", addr);
368 		safe_setenv("REMOTE_ADDR", addr);
369 		safe_setenv("DOCUMENT_ROOT", dir);
370 
371 		if (tls_peer_cert_provided(c->ctx)) {
372 			safe_setenv("AUTH_TYPE", "Certificate");
373 			safe_setenv("REMOTE_USER", tls_peer_cert_subject(c->ctx));
374 			safe_setenv("TLS_CLIENT_ISSUER", tls_peer_cert_issuer(c->ctx));
375 			safe_setenv("TLS_CLIENT_HASH", tls_peer_cert_hash(c->ctx));
376 		}
377 
378 		execvp(ex, argv);
379 		goto childerr;
380 	}
381 
382 	default:		/* parent */
383 		close(p[1]);
384 		close(c->fd);
385 		c->fd = p[0];
386 		c->child = pid;
387 		mark_nonblock(c->fd);
388 		c->state = S_SENDING;
389 		handle_cgi(fds, c);
390 		return 0;
391 	}
392 
393 err:
394 	if (!start_reply(fds, c, TEMP_FAILURE, "internal server error"))
395 		return 0;
396 	goodbye(fds, c);
397 	return 0;
398 
399 childerr:
400 	dprintf(p[1], "%d internal server error\r\n", TEMP_FAILURE);
401 	close(p[1]);
402 	_exit(1);
403 }
404 
405 void
406 cgi_poll_on_child(struct pollfd *fds, struct client *c)
407 {
408 	int fd;
409 
410 	if (c->waiting_on_child)
411 		return;
412 	c->waiting_on_child = 1;
413 
414 	fds->events = POLLIN;
415 
416 	fd = fds->fd;
417 	fds->fd = c->fd;
418 	c->fd = fd;
419 }
420 
421 void
422 cgi_poll_on_client(struct pollfd *fds, struct client *c)
423 {
424 	int fd;
425 
426 	if (!c->waiting_on_child)
427 		return;
428 	c->waiting_on_child = 0;
429 
430 	fd = fds->fd;
431 	fds->fd = c->fd;
432 	c->fd = fd;
433 }
434 
435 void
436 handle_cgi(struct pollfd *fds, struct client *c)
437 {
438 	ssize_t r;
439 
440 	/* ensure c->fd is the child and fds->fd the client */
441 	cgi_poll_on_client(fds, c);
442 
443 	while (1) {
444 		if (c->len == 0) {
445 			if ((r = read(c->fd, c->sbuf, sizeof(c->sbuf))) == 0)
446 				goto end;
447 			if (r == -1) {
448 				if (errno == EAGAIN || errno == EWOULDBLOCK) {
449 					cgi_poll_on_child(fds, c);
450 					return;
451 				}
452                                 goto end;
453 			}
454 			c->len = r;
455 			c->off = 0;
456 		}
457 
458 		while (c->len > 0) {
459 			switch (r = tls_write(c->ctx, c->sbuf + c->off, c->len)) {
460 			case -1:
461 				goto end;
462 
463 			case TLS_WANT_POLLOUT:
464 				fds->events = POLLOUT;
465 				return;
466 
467 			case TLS_WANT_POLLIN:
468 				fds->events = POLLIN;
469 				return;
470 
471 			default:
472                                 c->off += r;
473 				c->len -= r;
474 				break;
475 			}
476 		}
477 	}
478 
479 end:
480 	goodbye(fds, c);
481 }
482 
483 void
484 send_file(char *path, char *query, struct pollfd *fds, struct client *c)
485 {
486 	ssize_t ret, len;
487 
488 	if (c->fd == -1) {
489 		if (!open_file(path, query, fds, c))
490 			return;
491 		c->state = S_SENDING;
492 	}
493 
494 	len = (c->buf + c->len) - c->i;
495 
496 	while (len > 0) {
497 		switch (ret = tls_write(c->ctx, c->i, len)) {
498 		case -1:
499 			LOGE(c, "tls_write: %s", tls_error(c->ctx));
500 			goodbye(fds, c);
501 			return;
502 
503 		case TLS_WANT_POLLIN:
504 			fds->events = POLLIN;
505 			return;
506 
507 		case TLS_WANT_POLLOUT:
508 			fds->events = POLLOUT;
509 			return;
510 
511 		default:
512 			c->i += ret;
513 			len -= ret;
514 			break;
515 		}
516 	}
517 
518 	goodbye(fds, c);
519 }
520 
521 void
522 send_dir(char *path, struct pollfd *fds, struct client *client)
523 {
524 	char fpath[PATHBUF];
525 	size_t len;
526 
527 	bzero(fpath, PATHBUF);
528 
529 	if (path[0] != '.')
530 		fpath[0] = '.';
531 
532 	/* this cannot fail since sizeof(fpath) > maxlen of path */
533 	strlcat(fpath, path, PATHBUF);
534 	len = strlen(fpath);
535 
536 	/* add a trailing / in case. */
537 	if (fpath[len-1] != '/') {
538 		fpath[len] = '/';
539 	}
540 
541 	strlcat(fpath, "index.gmi", sizeof(fpath));
542 
543 	send_file(fpath, NULL, fds, client);
544 }
545 
546 void
547 handle(struct pollfd *fds, struct client *client)
548 {
549 	char buf[GEMINI_URL_LEN];
550 	const char *parse_err;
551 	struct uri uri;
552 
553 	switch (client->state) {
554 	case S_OPEN:
555 		bzero(buf, GEMINI_URL_LEN);
556 		switch (tls_read(client->ctx, buf, sizeof(buf)-1)) {
557 		case -1:
558 			LOGE(client, "tls_read: %s", tls_error(client->ctx));
559 			goodbye(fds, client);
560 			return;
561 
562 		case TLS_WANT_POLLIN:
563 			fds->events = POLLIN;
564 			return;
565 
566 		case TLS_WANT_POLLOUT:
567 			fds->events = POLLOUT;
568 			return;
569 		}
570 
571 		parse_err = "invalid request";
572 		if (!trim_req_uri(buf) || !parse_uri(buf, &uri, &parse_err)) {
573 			if (!start_reply(fds, client, BAD_REQUEST, parse_err))
574 				return;
575 			goodbye(fds, client);
576 			return;
577 		}
578 
579 		LOGI(client, "GET %s%s%s",
580 		    *uri.path ? uri.path : "/",
581 		    *uri.query ? "?" : "",
582 		    *uri.query ? uri.query : "");
583 
584 		send_file(uri.path, uri.query, fds, client);
585 		break;
586 
587 	case S_INITIALIZING:
588 		if (!start_reply(fds, client, client->code, client->meta))
589 			return;
590 
591 		if (client->code != SUCCESS) {
592 			/* we don't need a body */
593 			goodbye(fds, client);
594 			return;
595 		}
596 
597 		client->state = S_SENDING;
598 
599 		/* fallthrough */
600 
601 	case S_SENDING:
602 		if (client->child != -1)
603 			handle_cgi(fds, client);
604 		else
605 			send_file(NULL, NULL, fds, client);
606 		break;
607 
608 	case S_CLOSING:
609 		goodbye(fds, client);
610 		break;
611 
612 	default:
613 		/* unreachable */
614 		abort();
615 	}
616 }
617 
618 void
619 mark_nonblock(int fd)
620 {
621 	int flags;
622 
623 	if ((flags = fcntl(fd, F_GETFL)) == -1)
624 		fatal("fcntl(F_GETFL): %s", strerror(errno));
625 	if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1)
626 		fatal("fcntl(F_SETFL): %s", strerror(errno));
627 }
628 
629 int
630 make_socket(int port, int family)
631 {
632 	int sock, v;
633 	struct sockaddr_in addr4;
634 	struct sockaddr_in6 addr6;
635 	struct sockaddr *addr;
636 	socklen_t len;
637 
638         switch (family) {
639 	case AF_INET:
640 		bzero(&addr4, sizeof(addr4));
641 		addr4.sin_family = family;
642 		addr4.sin_port = htons(port);
643 		addr4.sin_addr.s_addr = INADDR_ANY;
644 		addr = (struct sockaddr*)&addr4;
645 		len = sizeof(addr4);
646 		break;
647 
648 	case AF_INET6:
649 		bzero(&addr6, sizeof(addr6));
650 		addr6.sin6_family = AF_INET6;
651 		addr6.sin6_port = htons(port);
652 		addr6.sin6_addr = in6addr_any;
653 		addr = (struct sockaddr*)&addr6;
654 		len = sizeof(addr6);
655 		break;
656 
657 	default:
658 		/* unreachable */
659 		abort();
660 	}
661 
662 	if ((sock = socket(family, SOCK_STREAM, 0)) == -1)
663 		fatal("socket: %s", strerror(errno));
664 
665 	v = 1;
666 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &v, sizeof(v)) == -1)
667 		fatal("setsockopt(SO_REUSEADDR): %s", strerror(errno));
668 
669 	v = 1;
670 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &v, sizeof(v)) == -1)
671 		fatal("setsockopt(SO_REUSEPORT): %s", strerror(errno));
672 
673 	mark_nonblock(sock);
674 
675 	if (bind(sock, addr, len) == -1)
676 		fatal("bind: %s", strerror(errno));
677 
678 	if (listen(sock, 16) == -1)
679 		fatal("listen: %s", strerror(errno));
680 
681 	return sock;
682 }
683 
684 void
685 do_accept(int sock, struct tls *ctx, struct pollfd *fds, struct client *clients)
686 {
687 	int i, fd;
688 	struct sockaddr_in addr;
689 	socklen_t len;
690 
691 	len = sizeof(addr);
692 	if ((fd = accept(sock, (struct sockaddr*)&addr, &len)) == -1) {
693 		if (errno == EWOULDBLOCK)
694 			return;
695 		fatal("accept: %s", strerror(errno));
696 	}
697 
698 	mark_nonblock(fd);
699 
700 	for (i = 0; i < MAX_USERS; ++i) {
701 		if (fds[i].fd == -1) {
702 			bzero(&clients[i], sizeof(struct client));
703 			if (tls_accept_socket(ctx, &clients[i].ctx, fd) == -1)
704 				break; /* goodbye fd! */
705 
706 			fds[i].fd = fd;
707 			fds[i].events = POLLIN;
708 
709 			clients[i].state = S_OPEN;
710 			clients[i].fd = -1;
711 			clients[i].child = -1;
712 			clients[i].buf = MAP_FAILED;
713 			clients[i].af = AF_INET;
714 			clients[i].addr = addr.sin_addr;
715 
716 			connected_clients++;
717 			return;
718 		}
719 	}
720 
721 	close(fd);
722 }
723 
724 void
725 goodbye(struct pollfd *pfd, struct client *c)
726 {
727 	ssize_t ret;
728 
729 	c->state = S_CLOSING;
730 
731 	ret = tls_close(c->ctx);
732 	if (ret == TLS_WANT_POLLIN) {
733 		pfd->events = POLLIN;
734 		return;
735 	}
736 	if (ret == TLS_WANT_POLLOUT) {
737 		pfd->events = POLLOUT;
738 		return;
739 	}
740 
741 	connected_clients--;
742 
743 	tls_free(c->ctx);
744 	c->ctx = NULL;
745 
746 	if (c->buf != MAP_FAILED)
747 		munmap(c->buf, c->len);
748 
749 	if (c->fd != -1)
750 		close(c->fd);
751 
752 	close(pfd->fd);
753 	pfd->fd = -1;
754 }
755 
756 void
757 loop(struct tls *ctx, int sock)
758 {
759 	int i;
760 	struct client clients[MAX_USERS];
761 	struct pollfd fds[MAX_USERS];
762 
763 	for (i = 0; i < MAX_USERS; ++i) {
764 		fds[i].fd = -1;
765 		fds[i].events = POLLIN;
766 		bzero(&clients[i], sizeof(struct client));
767 	}
768 
769 	fds[0].fd = sock;
770 
771 	for (;;) {
772 		if (poll(fds, MAX_USERS, INFTIM) == -1) {
773 			if (errno == EINTR) {
774                                 warnx("connected clients: %d",
775 				    connected_clients);
776 				continue;
777 			}
778 			fatal("poll: %s", strerror(errno));
779 		}
780 
781 		for (i = 0; i < MAX_USERS; i++) {
782 			if (fds[i].revents == 0)
783 				continue;
784 
785 			if (fds[i].revents & (POLLERR|POLLNVAL))
786 				fatal("bad fd %d: %s", fds[i].fd,
787 				    strerror(errno));
788 
789 			if (fds[i].revents & POLLHUP) {
790 				/* fds[i] may be the fd of the stdin
791 				 * of a cgi script that has exited. */
792 				if (!clients[i].waiting_on_child) {
793 					goodbye(&fds[i], &clients[i]);
794 					continue;
795 				}
796 			}
797 
798 			if (i == 0) { /* new client */
799 				do_accept(sock, ctx, fds, clients);
800 				continue;
801 			}
802 
803 			handle(&fds[i], &clients[i]);
804 		}
805 	}
806 }
807 
808 char *
809 absolutify_path(const char *path)
810 {
811 	char *wd, *r;
812 
813 	if (*path == '/')
814 		return strdup(path);
815 
816 	wd = getwd(NULL);
817 	if (asprintf(&r, "%s/%s", wd, path) == -1)
818 		err(1, "asprintf");
819 	free(wd);
820 	return r;
821 }
822 
823 void
824 usage(const char *me)
825 {
826 	fprintf(stderr,
827 	    "USAGE: %s [-h] [-c cert.pem] [-d docs] [-k key.pem] "
828 	    "[-l logfile] [-p port] [-x cgi-bin]\n",
829 	    me);
830 }
831 
832 int
833 main(int argc, char **argv)
834 {
835 	const char *cert = "cert.pem", *key = "key.pem";
836 	struct tls *ctx = NULL;
837 	struct tls_config *conf;
838 	int sock, ch;
839 	connected_clients = 0;
840 
841 	if ((dir = absolutify_path("docs")) == NULL)
842 		err(1, "absolutify_path");
843 
844 	cgi = NULL;
845 	port = 1965;
846 	foreground = 0;
847 
848 	while ((ch = getopt(argc, argv, "c:d:fhk:p:x:")) != -1) {
849 		switch (ch) {
850 		case 'c':
851 			cert = optarg;
852 			break;
853 
854 		case 'd':
855 			free((char*)dir);
856 			if ((dir = absolutify_path(optarg)) == NULL)
857 				err(1, "absolutify_path");
858 			break;
859 
860 		case 'f':
861 			foreground = 1;
862 			break;
863 
864 		case 'h':
865 			usage(*argv);
866 			return 0;
867 
868 		case 'k':
869 			key = optarg;
870 			break;
871 
872 		case 'p': {
873 			char *ep;
874 			long lval;
875 
876 			errno = 0;
877 			lval = strtol(optarg, &ep, 10);
878 			if (optarg[0] == '\0' || *ep != '\0')
879 				err(1, "not a number: %s", optarg);
880 			if (lval < 0 || lval > UINT16_MAX)
881 				err(1, "port number out of range: %s", optarg);
882 			port = lval;
883 			break;
884 		}
885 
886 		case 'x':
887 			cgi = optarg;
888 			break;
889 
890 		default:
891 			usage(*argv);
892 			return 1;
893 		}
894 	}
895 
896 	signal(SIGPIPE, SIG_IGN);
897 	signal(SIGCHLD, SIG_IGN);
898 
899 #ifdef SIGINFO
900 	signal(SIGINFO, sig_handler);
901 #endif
902 	signal(SIGUSR2, sig_handler);
903 
904 	if (!foreground)
905 		signal(SIGHUP, SIG_IGN);
906 
907 	if ((conf = tls_config_new()) == NULL)
908 		err(1, "tls_config_new");
909 
910 	/* optionally accept client certs, but don't try to verify them */
911 	tls_config_verify_client_optional(conf);
912 	tls_config_insecure_noverifycert(conf);
913 
914 	if (tls_config_set_protocols(conf,
915 	    TLS_PROTOCOL_TLSv1_2 | TLS_PROTOCOL_TLSv1_3) == -1)
916 		err(1, "tls_config_set_protocols");
917 
918 	if (tls_config_set_cert_file(conf, cert) == -1)
919 		err(1, "tls_config_set_cert_file: %s", cert);
920 
921 	if (tls_config_set_key_file(conf, key) == -1)
922 		err(1, "tls_config_set_key_file: %s", key);
923 
924 	if ((ctx = tls_server()) == NULL)
925 		err(1, "tls_server");
926 
927 	if (tls_configure(ctx, conf) == -1)
928 		errx(1, "tls_configure: %s", tls_error(ctx));
929 
930 	sock = make_socket(port, AF_INET);
931 
932 	if ((dirfd = open(dir, O_RDONLY | O_DIRECTORY)) == -1)
933 		err(1, "open: %s", dir);
934 
935 	if (!foreground && daemon(0, 1) == -1)
936 		exit(1);
937 
938 	if (unveil(dir, "rx") == -1)
939 		err(1, "unveil");
940 
941 	if (pledge("stdio rpath inet proc exec", NULL) == -1)
942 		err(1, "pledge");
943 
944 	/* drop proc and exec if cgi isn't enabled */
945 	if (cgi == NULL && pledge("stdio rpath inet", NULL) == -1)
946 		err(1, "pledge");
947 
948 	loop(ctx, sock);
949 
950 	close(sock);
951 	tls_free(ctx);
952 	tls_config_free(conf);
953 }