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Date:: Sun Jan 10 22:29:22 2021 UTC
Message:: log also the port of the client
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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 <netdb.h>
27 #include <signal.h>
28 #include <stdarg.h>
29 #include <string.h>
30 
31 #include "gmid.h"
32 
33 #define LOGE(c, fmt, ...) logs(LOG_ERR,    c, fmt, __VA_ARGS__)
34 #define LOGN(c, fmt, ...) logs(LOG_NOTICE, c, fmt, __VA_ARGS__)
35 #define LOGI(c, fmt, ...) logs(LOG_INFO,   c, fmt, __VA_ARGS__)
36 #define LOGD(c, fmt, ...) logs(LOG_DEBUG,  c, fmt, __VA_ARGS__)
37 
38 const char *dir, *cgi;
39 int dirfd;
40 int port;
41 int foreground;
42 int connected_clients;
43 
44 struct etm {			/* file extension to mime */
45 	const char	*mime;
46 	const char	*ext;
47 } filetypes[] = {
48 	{"application/pdf",	"pdf"},
49 
50 	{"image/gif",		"gif"},
51 	{"image/jpeg",		"jpg"},
52 	{"image/jpeg",		"jpeg"},
53 	{"image/png",		"png"},
54 	{"image/svg+xml",	"svg"},
55 
56 	{"text/gemini",		"gemini"},
57 	{"text/gemini",		"gmi"},
58 	{"text/markdown",	"markdown"},
59 	{"text/markdown",	"md"},
60 	{"text/plain",		"txt"},
61 	{"text/xml",		"xml"},
62 
63 	{NULL, NULL}
64 };
65 
66 static inline void
67 safe_setenv(const char *name, const char *val)
68 {
69 	if (val == NULL)
70 		val = "";
71 	setenv(name, val, 1);
72 }
73 
74 __attribute__ ((format (printf, 1, 2)))
75 static inline void __dead
76 fatal(const char *fmt, ...)
77 {
78 	va_list ap;
79 
80 	va_start(ap, fmt);
81 
82 	if (foreground) {
83 		vfprintf(stderr, fmt, ap);
84 		fprintf(stderr, "\n");
85 	} else
86 		vsyslog(LOG_DAEMON | LOG_CRIT, fmt, ap);
87 
88 	va_end(ap);
89 	exit(1);
90 }
91 
92 __attribute__ ((format (printf, 3, 4)))
93 static inline void
94 logs(int priority, struct client *c,
95     const char *fmt, ...)
96 {
97 	char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
98 	char *fmted, *s;
99 	size_t len;
100 	int ec;
101 	va_list ap;
102 
103 	va_start(ap, fmt);
104 
105 	len = sizeof(c->addr);
106 	ec = getnameinfo((struct sockaddr*)&c->addr, len,
107 	    hbuf, sizeof(hbuf),
108 	    sbuf, sizeof(sbuf),
109 	    NI_NUMERICHOST | NI_NUMERICSERV);
110 	if (ec != 0)
111 		fatal("getnameinfo: %s", gai_strerror(ec));
112 
113 	if (vasprintf(&fmted, fmt, ap) == -1)
114 		fatal("vasprintf: %s", strerror(errno));
115 
116 	if (foreground)
117 		fprintf(stderr, "%s:%s %s\n", hbuf, sbuf, fmted);
118 	else {
119 		if (asprintf(&s, "%s:%s %s", hbuf, sbuf, fmted) == -1)
120 			fatal("asprintf: %s", strerror(errno));
121 		syslog(priority | LOG_DAEMON, "%s", s);
122 		free(s);
123 	}
124 
125 	free(fmted);
126 
127 	va_end(ap);
128 }
129 
130 void
131 sig_handler(int sig)
132 {
133 	(void)sig;
134 }
135 
136 int
137 starts_with(const char *str, const char *prefix)
138 {
139 	size_t i;
140 
141 	for (i = 0; prefix[i] != '\0'; ++i)
142 		if (str[i] != prefix[i])
143 			return 0;
144 	return 1;
145 }
146 
147 int
148 start_reply(struct pollfd *pfd, struct client *client, int code, const char *reason)
149 {
150 	char buf[1030] = {0}; 	/* status + ' ' + max reply len + \r\n\0 */
151 	int len;
152 	int ret;
153 
154 	client->code = code;
155 	client->meta = reason;
156 	client->state = S_INITIALIZING;
157 
158 	len = snprintf(buf, sizeof(buf), "%d %s\r\n", code, reason);
159 	assert(len < (int)sizeof(buf));
160 	ret = tls_write(client->ctx, buf, len);
161 	if (ret == TLS_WANT_POLLIN) {
162 		pfd->events = POLLIN;
163 		return 0;
164 	}
165 
166 	if (ret == TLS_WANT_POLLOUT) {
167 		pfd->events = POLLOUT;
168 		return 0;
169 	}
170 
171 	return 1;
172 }
173 
174 ssize_t
175 filesize(int fd)
176 {
177 	ssize_t len;
178 
179 	if ((len = lseek(fd, 0, SEEK_END)) == -1)
180 		return -1;
181 	if (lseek(fd, 0, SEEK_SET) == -1)
182 		return -1;
183 	return len;
184 }
185 
186 const char *
187 path_ext(const char *path)
188 {
189 	const char *end;
190 
191 	end = path + strlen(path)-1; /* the last byte before the NUL */
192 	for (; end != path; --end) {
193 		if (*end == '.')
194 			return end+1;
195 		if (*end == '/')
196 			break;
197 	}
198 
199 	return NULL;
200 }
201 
202 const char *
203 mime(const char *path)
204 {
205 	const char *ext, *def = "application/octet-stream";
206 	struct etm *t;
207 
208 	if ((ext = path_ext(path)) == NULL)
209 		return def;
210 
211 	for (t = filetypes; t->mime != NULL; ++t)
212 		if (!strcmp(ext, t->ext))
213 			return t->mime;
214 
215 	return def;
216 }
217 
218 int
219 check_path(struct client *c, const char *path, int *fd)
220 {
221 	struct stat sb;
222 
223 	assert(path != NULL);
224 	if ((*fd = openat(dirfd, *path ? path : ".",
225 		    O_RDONLY | O_NOFOLLOW | O_CLOEXEC)) == -1) {
226 		return FILE_MISSING;
227 	}
228 
229 	if (fstat(*fd, &sb) == -1) {
230 		LOGN(c, "failed stat for %s: %s", path, strerror(errno));
231 		return FILE_MISSING;
232 	}
233 
234 	if (S_ISDIR(sb.st_mode))
235 		return FILE_DIRECTORY;
236 
237 	if (sb.st_mode & S_IXUSR)
238 		return FILE_EXECUTABLE;
239 
240 	return FILE_EXISTS;
241 }
242 
243 /*
244  * the inverse of this algorithm, i.e. starting from the start of the
245  * path + strlen(cgi), and checking if each component, should be
246  * faster.  But it's tedious to write.  This does the opposite: starts
247  * from the end and strip one component at a time, until either an
248  * executable is found or we emptied the path.
249  */
250 int
251 check_for_cgi(char *path, char *query, struct pollfd *fds, struct client *c)
252 {
253 	char *end;
254 	end = strchr(path, '\0');
255 
256 	/* NB: assume CGI is enabled and path matches cgi */
257 
258 	while (end > path) {
259 		/* go up one level.  UNIX paths are simple and POSIX
260 		 * dirname, with its ambiguities on if the given path
261 		 * is changed or not, gives me headaches. */
262 		while (*end != '/')
263 			end--;
264 		*end = '\0';
265 
266 		switch (check_path(c, path, &c->fd)) {
267 		case FILE_EXECUTABLE:
268 			return start_cgi(path, end+1, query, fds,c);
269 		case FILE_MISSING:
270 			break;
271 		default:
272 			goto err;
273 		}
274 
275 		*end = '/';
276 		end--;
277 	}
278 
279 err:
280 	if (!start_reply(fds, c, NOT_FOUND, "not found"))
281 		return 0;
282 	goodbye(fds, c);
283 	return 0;
284 }
285 
286 
287 int
288 open_file(char *fpath, char *query, struct pollfd *fds, struct client *c)
289 {
290 	switch (check_path(c, fpath, &c->fd)) {
291 	case FILE_EXECUTABLE:
292 		if (cgi != NULL && starts_with(fpath, cgi))
293 			return start_cgi(fpath, "", query, fds, c);
294 
295 		/* fallthrough */
296 
297 	case FILE_EXISTS:
298 		if ((c->len = filesize(c->fd)) == -1) {
299 			LOGE(c, "failed to get file size for %s", fpath);
300 			goodbye(fds, c);
301 			return 0;
302 		}
303 
304 		if ((c->buf = mmap(NULL, c->len, PROT_READ, MAP_PRIVATE,
305 			    c->fd, 0)) == MAP_FAILED) {
306 			warn("mmap: %s", fpath);
307 			goodbye(fds, c);
308 			return 0;
309 		}
310 		c->i = c->buf;
311 		return start_reply(fds, c, SUCCESS, mime(fpath));
312 
313 	case FILE_DIRECTORY:
314 		LOGD(c, "%s is a directory, trying %s/index.gmi", fpath, fpath);
315 		close(c->fd);
316 		c->fd = -1;
317 		send_dir(fpath, fds, c);
318 		return 0;
319 
320 	case FILE_MISSING:
321 		if (cgi != NULL && starts_with(fpath, cgi))
322 			return check_for_cgi(fpath, query, fds, c);
323 
324 		if (!start_reply(fds, c, NOT_FOUND, "not found"))
325 			return 0;
326 		goodbye(fds, c);
327 		return 0;
328 
329 	default:
330 		/* unreachable */
331 		abort();
332 	}
333 }
334 
335 int
336 start_cgi(const char *spath, const char *relpath, const char *query,
337     struct pollfd *fds, struct client *c)
338 {
339 	pid_t pid;
340 	int p[2]; 		/* read end, write end */
341 
342 	if (pipe(p) == -1)
343 		goto err;
344 
345 	switch (pid = fork()) {
346 	case -1:
347 		goto err;
348 
349 	case 0: { 		/* child */
350 		char *ex, *requri, *portno;
351 		char addr[INET_ADDRSTRLEN];
352 		char *argv[] = { NULL, NULL, NULL };
353 
354 		close(p[0]);
355 		if (dup2(p[1], 1) == -1)
356 			goto childerr;
357 
358 		if (inet_ntop(c->af, &c->addr, addr, sizeof(addr)) == NULL)
359 			goto childerr;
360 
361 		if (asprintf(&portno, "%d", port) == -1)
362 			goto childerr;
363 
364 		if (asprintf(&ex, "%s/%s", dir, spath) == -1)
365 			goto childerr;
366 
367 		if (asprintf(&requri, "%s%s%s", spath,
368 		    *relpath == '\0' ? "" : "/",
369 		    relpath) == -1)
370 			goto childerr;
371 
372 		argv[0] = argv[1] = ex;
373 
374 		/* fix the env */
375 		safe_setenv("GATEWAY_INTERFACE", "CGI/1.1");
376 		safe_setenv("SERVER_SOFTWARE", "gmid");
377 		safe_setenv("SERVER_PORT", portno);
378 		/* setenv("SERVER_NAME", "", 1); */
379 		safe_setenv("SCRIPT_NAME", spath);
380 		safe_setenv("SCRIPT_EXECUTABLE", ex);
381 		safe_setenv("REQUEST_URI", requri);
382 		safe_setenv("REQUEST_RELATIVE", relpath);
383 		safe_setenv("QUERY_STRING", query);
384 		safe_setenv("REMOTE_HOST", addr);
385 		safe_setenv("REMOTE_ADDR", addr);
386 		safe_setenv("DOCUMENT_ROOT", dir);
387 
388 		if (tls_peer_cert_provided(c->ctx)) {
389 			safe_setenv("AUTH_TYPE", "Certificate");
390 			safe_setenv("REMOTE_USER", tls_peer_cert_subject(c->ctx));
391 			safe_setenv("TLS_CLIENT_ISSUER", tls_peer_cert_issuer(c->ctx));
392 			safe_setenv("TLS_CLIENT_HASH", tls_peer_cert_hash(c->ctx));
393 		}
394 
395 		execvp(ex, argv);
396 		goto childerr;
397 	}
398 
399 	default:		/* parent */
400 		close(p[1]);
401 		close(c->fd);
402 		c->fd = p[0];
403 		c->child = pid;
404 		mark_nonblock(c->fd);
405 		c->state = S_SENDING;
406 		handle_cgi(fds, c);
407 		return 0;
408 	}
409 
410 err:
411 	if (!start_reply(fds, c, TEMP_FAILURE, "internal server error"))
412 		return 0;
413 	goodbye(fds, c);
414 	return 0;
415 
416 childerr:
417 	dprintf(p[1], "%d internal server error\r\n", TEMP_FAILURE);
418 	close(p[1]);
419 	_exit(1);
420 }
421 
422 void
423 cgi_poll_on_child(struct pollfd *fds, struct client *c)
424 {
425 	int fd;
426 
427 	if (c->waiting_on_child)
428 		return;
429 	c->waiting_on_child = 1;
430 
431 	fds->events = POLLIN;
432 
433 	fd = fds->fd;
434 	fds->fd = c->fd;
435 	c->fd = fd;
436 }
437 
438 void
439 cgi_poll_on_client(struct pollfd *fds, struct client *c)
440 {
441 	int fd;
442 
443 	if (!c->waiting_on_child)
444 		return;
445 	c->waiting_on_child = 0;
446 
447 	fd = fds->fd;
448 	fds->fd = c->fd;
449 	c->fd = fd;
450 }
451 
452 void
453 handle_cgi(struct pollfd *fds, struct client *c)
454 {
455 	ssize_t r;
456 
457 	/* ensure c->fd is the child and fds->fd the client */
458 	cgi_poll_on_client(fds, c);
459 
460 	while (1) {
461 		if (c->len == 0) {
462 			if ((r = read(c->fd, c->sbuf, sizeof(c->sbuf))) == 0)
463 				goto end;
464 			if (r == -1) {
465 				if (errno == EAGAIN || errno == EWOULDBLOCK) {
466 					cgi_poll_on_child(fds, c);
467 					return;
468 				}
469                                 goto end;
470 			}
471 			c->len = r;
472 			c->off = 0;
473 		}
474 
475 		while (c->len > 0) {
476 			switch (r = tls_write(c->ctx, c->sbuf + c->off, c->len)) {
477 			case -1:
478 				goto end;
479 
480 			case TLS_WANT_POLLOUT:
481 				fds->events = POLLOUT;
482 				return;
483 
484 			case TLS_WANT_POLLIN:
485 				fds->events = POLLIN;
486 				return;
487 
488 			default:
489                                 c->off += r;
490 				c->len -= r;
491 				break;
492 			}
493 		}
494 	}
495 
496 end:
497 	goodbye(fds, c);
498 }
499 
500 void
501 send_file(char *path, char *query, struct pollfd *fds, struct client *c)
502 {
503 	ssize_t ret, len;
504 
505 	if (c->fd == -1) {
506 		if (!open_file(path, query, fds, c))
507 			return;
508 		c->state = S_SENDING;
509 	}
510 
511 	len = (c->buf + c->len) - c->i;
512 
513 	while (len > 0) {
514 		switch (ret = tls_write(c->ctx, c->i, len)) {
515 		case -1:
516 			LOGE(c, "tls_write: %s", tls_error(c->ctx));
517 			goodbye(fds, c);
518 			return;
519 
520 		case TLS_WANT_POLLIN:
521 			fds->events = POLLIN;
522 			return;
523 
524 		case TLS_WANT_POLLOUT:
525 			fds->events = POLLOUT;
526 			return;
527 
528 		default:
529 			c->i += ret;
530 			len -= ret;
531 			break;
532 		}
533 	}
534 
535 	goodbye(fds, c);
536 }
537 
538 void
539 send_dir(char *path, struct pollfd *fds, struct client *client)
540 {
541 	char fpath[PATHBUF];
542 	size_t len;
543 
544 	bzero(fpath, PATHBUF);
545 
546 	if (path[0] != '.')
547 		fpath[0] = '.';
548 
549 	/* this cannot fail since sizeof(fpath) > maxlen of path */
550 	strlcat(fpath, path, PATHBUF);
551 	len = strlen(fpath);
552 
553 	/* add a trailing / in case. */
554 	if (fpath[len-1] != '/') {
555 		fpath[len] = '/';
556 	}
557 
558 	strlcat(fpath, "index.gmi", sizeof(fpath));
559 
560 	send_file(fpath, NULL, fds, client);
561 }
562 
563 void
564 handle(struct pollfd *fds, struct client *client)
565 {
566 	char buf[GEMINI_URL_LEN];
567 	const char *parse_err;
568 	struct uri uri;
569 
570 	switch (client->state) {
571 	case S_OPEN:
572 		bzero(buf, GEMINI_URL_LEN);
573 		switch (tls_read(client->ctx, buf, sizeof(buf)-1)) {
574 		case -1:
575 			LOGE(client, "tls_read: %s", tls_error(client->ctx));
576 			goodbye(fds, client);
577 			return;
578 
579 		case TLS_WANT_POLLIN:
580 			fds->events = POLLIN;
581 			return;
582 
583 		case TLS_WANT_POLLOUT:
584 			fds->events = POLLOUT;
585 			return;
586 		}
587 
588 		parse_err = "invalid request";
589 		if (!trim_req_uri(buf) || !parse_uri(buf, &uri, &parse_err)) {
590 			if (!start_reply(fds, client, BAD_REQUEST, parse_err))
591 				return;
592 			goodbye(fds, client);
593 			return;
594 		}
595 
596 		LOGI(client, "GET %s%s%s",
597 		    *uri.path ? uri.path : "/",
598 		    *uri.query ? "?" : "",
599 		    *uri.query ? uri.query : "");
600 
601 		send_file(uri.path, uri.query, fds, client);
602 		break;
603 
604 	case S_INITIALIZING:
605 		if (!start_reply(fds, client, client->code, client->meta))
606 			return;
607 
608 		if (client->code != SUCCESS) {
609 			/* we don't need a body */
610 			goodbye(fds, client);
611 			return;
612 		}
613 
614 		client->state = S_SENDING;
615 
616 		/* fallthrough */
617 
618 	case S_SENDING:
619 		if (client->child != -1)
620 			handle_cgi(fds, client);
621 		else
622 			send_file(NULL, NULL, fds, client);
623 		break;
624 
625 	case S_CLOSING:
626 		goodbye(fds, client);
627 		break;
628 
629 	default:
630 		/* unreachable */
631 		abort();
632 	}
633 }
634 
635 void
636 mark_nonblock(int fd)
637 {
638 	int flags;
639 
640 	if ((flags = fcntl(fd, F_GETFL)) == -1)
641 		fatal("fcntl(F_GETFL): %s", strerror(errno));
642 	if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1)
643 		fatal("fcntl(F_SETFL): %s", strerror(errno));
644 }
645 
646 int
647 make_socket(int port, int family)
648 {
649 	int sock, v;
650 	struct sockaddr_in addr4;
651 	struct sockaddr_in6 addr6;
652 	struct sockaddr *addr;
653 	socklen_t len;
654 
655         switch (family) {
656 	case AF_INET:
657 		bzero(&addr4, sizeof(addr4));
658 		addr4.sin_family = family;
659 		addr4.sin_port = htons(port);
660 		addr4.sin_addr.s_addr = INADDR_ANY;
661 		addr = (struct sockaddr*)&addr4;
662 		len = sizeof(addr4);
663 		break;
664 
665 	case AF_INET6:
666 		bzero(&addr6, sizeof(addr6));
667 		addr6.sin6_family = AF_INET6;
668 		addr6.sin6_port = htons(port);
669 		addr6.sin6_addr = in6addr_any;
670 		addr = (struct sockaddr*)&addr6;
671 		len = sizeof(addr6);
672 		break;
673 
674 	default:
675 		/* unreachable */
676 		abort();
677 	}
678 
679 	if ((sock = socket(family, SOCK_STREAM, 0)) == -1)
680 		fatal("socket: %s", strerror(errno));
681 
682 	v = 1;
683 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &v, sizeof(v)) == -1)
684 		fatal("setsockopt(SO_REUSEADDR): %s", strerror(errno));
685 
686 	v = 1;
687 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &v, sizeof(v)) == -1)
688 		fatal("setsockopt(SO_REUSEPORT): %s", strerror(errno));
689 
690 	mark_nonblock(sock);
691 
692 	if (bind(sock, addr, len) == -1)
693 		fatal("bind: %s", strerror(errno));
694 
695 	if (listen(sock, 16) == -1)
696 		fatal("listen: %s", strerror(errno));
697 
698 	return sock;
699 }
700 
701 void
702 do_accept(int sock, struct tls *ctx, struct pollfd *fds, struct client *clients)
703 {
704 	int i, fd;
705 	struct sockaddr_storage addr;
706 	socklen_t len;
707 
708 	len = sizeof(addr);
709 	if ((fd = accept(sock, (struct sockaddr*)&addr, &len)) == -1) {
710 		if (errno == EWOULDBLOCK)
711 			return;
712 		fatal("accept: %s", strerror(errno));
713 	}
714 
715 	mark_nonblock(fd);
716 
717 	for (i = 0; i < MAX_USERS; ++i) {
718 		if (fds[i].fd == -1) {
719 			bzero(&clients[i], sizeof(struct client));
720 			if (tls_accept_socket(ctx, &clients[i].ctx, fd) == -1)
721 				break; /* goodbye fd! */
722 
723 			fds[i].fd = fd;
724 			fds[i].events = POLLIN;
725 
726 			clients[i].state = S_OPEN;
727 			clients[i].fd = -1;
728 			clients[i].child = -1;
729 			clients[i].buf = MAP_FAILED;
730 			clients[i].af = AF_INET;
731 			clients[i].addr = addr;
732 
733 			connected_clients++;
734 			return;
735 		}
736 	}
737 
738 	close(fd);
739 }
740 
741 void
742 goodbye(struct pollfd *pfd, struct client *c)
743 {
744 	ssize_t ret;
745 
746 	c->state = S_CLOSING;
747 
748 	ret = tls_close(c->ctx);
749 	if (ret == TLS_WANT_POLLIN) {
750 		pfd->events = POLLIN;
751 		return;
752 	}
753 	if (ret == TLS_WANT_POLLOUT) {
754 		pfd->events = POLLOUT;
755 		return;
756 	}
757 
758 	connected_clients--;
759 
760 	tls_free(c->ctx);
761 	c->ctx = NULL;
762 
763 	if (c->buf != MAP_FAILED)
764 		munmap(c->buf, c->len);
765 
766 	if (c->fd != -1)
767 		close(c->fd);
768 
769 	close(pfd->fd);
770 	pfd->fd = -1;
771 }
772 
773 void
774 loop(struct tls *ctx, int sock)
775 {
776 	int i;
777 	struct client clients[MAX_USERS];
778 	struct pollfd fds[MAX_USERS];
779 
780 	for (i = 0; i < MAX_USERS; ++i) {
781 		fds[i].fd = -1;
782 		fds[i].events = POLLIN;
783 		bzero(&clients[i], sizeof(struct client));
784 	}
785 
786 	fds[0].fd = sock;
787 
788 	for (;;) {
789 		if (poll(fds, MAX_USERS, INFTIM) == -1) {
790 			if (errno == EINTR) {
791                                 warnx("connected clients: %d",
792 				    connected_clients);
793 				continue;
794 			}
795 			fatal("poll: %s", strerror(errno));
796 		}
797 
798 		for (i = 0; i < MAX_USERS; i++) {
799 			if (fds[i].revents == 0)
800 				continue;
801 
802 			if (fds[i].revents & (POLLERR|POLLNVAL))
803 				fatal("bad fd %d: %s", fds[i].fd,
804 				    strerror(errno));
805 
806 			if (fds[i].revents & POLLHUP) {
807 				/* fds[i] may be the fd of the stdin
808 				 * of a cgi script that has exited. */
809 				if (!clients[i].waiting_on_child) {
810 					goodbye(&fds[i], &clients[i]);
811 					continue;
812 				}
813 			}
814 
815 			if (i == 0) { /* new client */
816 				do_accept(sock, ctx, fds, clients);
817 				continue;
818 			}
819 
820 			handle(&fds[i], &clients[i]);
821 		}
822 	}
823 }
824 
825 char *
826 absolutify_path(const char *path)
827 {
828 	char *wd, *r;
829 
830 	if (*path == '/')
831 		return strdup(path);
832 
833 	wd = getwd(NULL);
834 	if (asprintf(&r, "%s/%s", wd, path) == -1)
835 		err(1, "asprintf");
836 	free(wd);
837 	return r;
838 }
839 
840 void
841 usage(const char *me)
842 {
843 	fprintf(stderr,
844 	    "USAGE: %s [-h] [-c cert.pem] [-d docs] [-k key.pem] "
845 	    "[-l logfile] [-p port] [-x cgi-bin]\n",
846 	    me);
847 }
848 
849 int
850 main(int argc, char **argv)
851 {
852 	const char *cert = "cert.pem", *key = "key.pem";
853 	struct tls *ctx = NULL;
854 	struct tls_config *conf;
855 	int sock, ch;
856 	connected_clients = 0;
857 
858 	if ((dir = absolutify_path("docs")) == NULL)
859 		err(1, "absolutify_path");
860 
861 	cgi = NULL;
862 	port = 1965;
863 	foreground = 0;
864 
865 	while ((ch = getopt(argc, argv, "c:d:fhk:p:x:")) != -1) {
866 		switch (ch) {
867 		case 'c':
868 			cert = optarg;
869 			break;
870 
871 		case 'd':
872 			free((char*)dir);
873 			if ((dir = absolutify_path(optarg)) == NULL)
874 				err(1, "absolutify_path");
875 			break;
876 
877 		case 'f':
878 			foreground = 1;
879 			break;
880 
881 		case 'h':
882 			usage(*argv);
883 			return 0;
884 
885 		case 'k':
886 			key = optarg;
887 			break;
888 
889 		case 'p': {
890 			char *ep;
891 			long lval;
892 
893 			errno = 0;
894 			lval = strtol(optarg, &ep, 10);
895 			if (optarg[0] == '\0' || *ep != '\0')
896 				err(1, "not a number: %s", optarg);
897 			if (lval < 0 || lval > UINT16_MAX)
898 				err(1, "port number out of range: %s", optarg);
899 			port = lval;
900 			break;
901 		}
902 
903 		case 'x':
904 			cgi = optarg;
905 			break;
906 
907 		default:
908 			usage(*argv);
909 			return 1;
910 		}
911 	}
912 
913 	signal(SIGPIPE, SIG_IGN);
914 	signal(SIGCHLD, SIG_IGN);
915 
916 #ifdef SIGINFO
917 	signal(SIGINFO, sig_handler);
918 #endif
919 	signal(SIGUSR2, sig_handler);
920 
921 	if (!foreground)
922 		signal(SIGHUP, SIG_IGN);
923 
924 	if ((conf = tls_config_new()) == NULL)
925 		err(1, "tls_config_new");
926 
927 	/* optionally accept client certs, but don't try to verify them */
928 	tls_config_verify_client_optional(conf);
929 	tls_config_insecure_noverifycert(conf);
930 
931 	if (tls_config_set_protocols(conf,
932 	    TLS_PROTOCOL_TLSv1_2 | TLS_PROTOCOL_TLSv1_3) == -1)
933 		err(1, "tls_config_set_protocols");
934 
935 	if (tls_config_set_cert_file(conf, cert) == -1)
936 		err(1, "tls_config_set_cert_file: %s", cert);
937 
938 	if (tls_config_set_key_file(conf, key) == -1)
939 		err(1, "tls_config_set_key_file: %s", key);
940 
941 	if ((ctx = tls_server()) == NULL)
942 		err(1, "tls_server");
943 
944 	if (tls_configure(ctx, conf) == -1)
945 		errx(1, "tls_configure: %s", tls_error(ctx));
946 
947 	sock = make_socket(port, AF_INET);
948 
949 	if ((dirfd = open(dir, O_RDONLY | O_DIRECTORY)) == -1)
950 		err(1, "open: %s", dir);
951 
952 	if (!foreground && daemon(0, 1) == -1)
953 		exit(1);
954 
955 	if (unveil(dir, "rx") == -1)
956 		err(1, "unveil");
957 
958 	if (pledge("stdio rpath inet proc exec", NULL) == -1)
959 		err(1, "pledge");
960 
961 	/* drop proc and exec if cgi isn't enabled */
962 	if (cgi == NULL && pledge("stdio rpath inet", NULL) == -1)
963 		err(1, "pledge");
964 
965 	loop(ctx, sock);
966 
967 	close(sock);
968 	tls_free(ctx);
969 	tls_config_free(conf);
970 }