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/stat.h>
19 
20 #include <assert.h>
21 #include <err.h>
22 #include <errno.h>
23 #include <fcntl.h>
24 #include <limits.h>
25 #include <netdb.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 struct vhost hosts[HOSTSLEN];
38 
39 int connected_clients;
40 int goterror;
41 
42 struct conf conf;
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 __attribute__ ((__noreturn__))
76 static inline void
77 fatal(const char *fmt, ...)
78 {
79 	va_list ap;
80 
81 	va_start(ap, fmt);
82 
83 	if (conf.foreground) {
84 		vfprintf(stderr, fmt, ap);
85 		fprintf(stderr, "\n");
86 	} else
87 		vsyslog(LOG_DAEMON | LOG_CRIT, fmt, ap);
88 
89 	va_end(ap);
90 	exit(1);
91 }
92 
93 __attribute__ ((format (printf, 3, 4)))
94 static inline void
95 logs(int priority, struct client *c,
96     const char *fmt, ...)
97 {
98 	char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
99 	char *fmted, *s;
100 	size_t len;
101 	int ec;
102 	va_list ap;
103 
104 	va_start(ap, fmt);
105 
106 	len = sizeof(c->addr);
107 	ec = getnameinfo((struct sockaddr*)&c->addr, len,
108 	    hbuf, sizeof(hbuf),
109 	    sbuf, sizeof(sbuf),
110 	    NI_NUMERICHOST | NI_NUMERICSERV);
111 	if (ec != 0)
112 		fatal("getnameinfo: %s", gai_strerror(ec));
113 
114 	if (vasprintf(&fmted, fmt, ap) == -1)
115 		fatal("vasprintf: %s", strerror(errno));
116 
117 	if (conf.foreground)
118 		fprintf(stderr, "%s:%s %s\n", hbuf, sbuf, fmted);
119 	else {
120 		if (asprintf(&s, "%s:%s %s", hbuf, sbuf, fmted) == -1)
121 			fatal("asprintf: %s", strerror(errno));
122 		syslog(priority | LOG_DAEMON, "%s", s);
123 		free(s);
124 	}
125 
126 	free(fmted);
127 
128 	va_end(ap);
129 }
130 
131 void
132 sig_handler(int sig)
133 {
134 	(void)sig;
135 }
136 
137 int
138 starts_with(const char *str, const char *prefix)
139 {
140 	size_t i;
141 
142 	for (i = 0; prefix[i] != '\0'; ++i)
143 		if (str[i] != prefix[i])
144 			return 0;
145 	return 1;
146 }
147 
148 int
149 start_reply(struct pollfd *pfd, struct client *client, int code, const char *reason)
150 {
151 	char buf[1030] = {0}; 	/* status + ' ' + max reply len + \r\n\0 */
152 	int len;
153 	int ret;
154 
155 	client->code = code;
156 	client->meta = reason;
157 	client->state = S_INITIALIZING;
158 
159 	len = snprintf(buf, sizeof(buf), "%d %s\r\n", code, reason);
160 	assert(len < (int)sizeof(buf));
161 	ret = tls_write(client->ctx, buf, len);
162 	if (ret == TLS_WANT_POLLIN) {
163 		pfd->events = POLLIN;
164 		return 0;
165 	}
166 
167 	if (ret == TLS_WANT_POLLOUT) {
168 		pfd->events = POLLOUT;
169 		return 0;
170 	}
171 
172 	return 1;
173 }
174 
175 ssize_t
176 filesize(int fd)
177 {
178 	ssize_t len;
179 
180 	if ((len = lseek(fd, 0, SEEK_END)) == -1)
181 		return -1;
182 	if (lseek(fd, 0, SEEK_SET) == -1)
183 		return -1;
184 	return len;
185 }
186 
187 const char *
188 path_ext(const char *path)
189 {
190 	const char *end;
191 
192 	end = path + strlen(path)-1; /* the last byte before the NUL */
193 	for (; end != path; --end) {
194 		if (*end == '.')
195 			return end+1;
196 		if (*end == '/')
197 			break;
198 	}
199 
200 	return NULL;
201 }
202 
203 const char *
204 mime(const char *path)
205 {
206 	const char *ext, *def = "application/octet-stream";
207 	struct etm *t;
208 
209 	if ((ext = path_ext(path)) == NULL)
210 		return def;
211 
212 	for (t = filetypes; t->mime != NULL; ++t)
213 		if (!strcmp(ext, t->ext))
214 			return t->mime;
215 
216 	return def;
217 }
218 
219 int
220 check_path(struct client *c, const char *path, int *fd)
221 {
222 	struct stat sb;
223 
224 	assert(path != NULL);
225 	if ((*fd = openat(c->host->dirfd, *path ? path : ".",
226 		    O_RDONLY | O_NOFOLLOW | O_CLOEXEC)) == -1) {
227 		return FILE_MISSING;
228 	}
229 
230 	if (fstat(*fd, &sb) == -1) {
231 		LOGN(c, "failed stat for %s: %s", path, strerror(errno));
232 		return FILE_MISSING;
233 	}
234 
235 	if (S_ISDIR(sb.st_mode))
236 		return FILE_DIRECTORY;
237 
238 	if (sb.st_mode & S_IXUSR)
239 		return FILE_EXECUTABLE;
240 
241 	return FILE_EXISTS;
242 }
243 
244 /*
245  * the inverse of this algorithm, i.e. starting from the start of the
246  * path + strlen(cgi), and checking if each component, should be
247  * faster.  But it's tedious to write.  This does the opposite: starts
248  * from the end and strip one component at a time, until either an
249  * executable is found or we emptied the path.
250  */
251 int
252 check_for_cgi(char *path, char *query, struct pollfd *fds, struct client *c)
253 {
254 	char *end;
255 	end = strchr(path, '\0');
256 
257 	/* NB: assume CGI is enabled and path matches cgi */
258 
259 	while (end > path) {
260 		/* go up one level.  UNIX paths are simple and POSIX
261 		 * dirname, with its ambiguities on if the given path
262 		 * is changed or not, gives me headaches. */
263 		while (*end != '/')
264 			end--;
265 		*end = '\0';
266 
267 		switch (check_path(c, path, &c->fd)) {
268 		case FILE_EXECUTABLE:
269 			return start_cgi(path, end+1, query, fds,c);
270 		case FILE_MISSING:
271 			break;
272 		default:
273 			goto err;
274 		}
275 
276 		*end = '/';
277 		end--;
278 	}
279 
280 err:
281 	if (!start_reply(fds, c, NOT_FOUND, "not found"))
282 		return 0;
283 	goodbye(fds, c);
284 	return 0;
285 }
286 
287 
288 int
289 open_file(char *fpath, char *query, struct pollfd *fds, struct client *c)
290 {
291 	switch (check_path(c, fpath, &c->fd)) {
292 	case FILE_EXECUTABLE:
293 		if (c->host->cgi != NULL && starts_with(fpath, c->host->cgi))
294 			return start_cgi(fpath, "", query, fds, c);
295 
296 		/* fallthrough */
297 
298 	case FILE_EXISTS:
299 		if ((c->len = filesize(c->fd)) == -1) {
300 			LOGE(c, "failed to get file size for %s", fpath);
301 			goodbye(fds, c);
302 			return 0;
303 		}
304 
305 		if ((c->buf = mmap(NULL, c->len, PROT_READ, MAP_PRIVATE,
306 			    c->fd, 0)) == MAP_FAILED) {
307 			warn("mmap: %s", fpath);
308 			goodbye(fds, c);
309 			return 0;
310 		}
311 		c->i = c->buf;
312 		return start_reply(fds, c, SUCCESS, mime(fpath));
313 
314 	case FILE_DIRECTORY:
315 		LOGD(c, "%s is a directory, trying %s/index.gmi", fpath, fpath);
316 		close(c->fd);
317 		c->fd = -1;
318 		send_dir(fpath, fds, c);
319 		return 0;
320 
321 	case FILE_MISSING:
322 		if (c->host->cgi != NULL && starts_with(fpath, c->host->cgi))
323 			return check_for_cgi(fpath, query, fds, c);
324 
325 		if (!start_reply(fds, c, NOT_FOUND, "not found"))
326 			return 0;
327 		goodbye(fds, c);
328 		return 0;
329 
330 	default:
331 		/* unreachable */
332 		abort();
333 	}
334 }
335 
336 int
337 start_cgi(const char *spath, const char *relpath, const char *query,
338     struct pollfd *fds, struct client *c)
339 {
340 	pid_t pid;
341 	int p[2]; 		/* read end, write end */
342 
343 	if (pipe(p) == -1)
344 		goto err;
345 
346 	switch (pid = fork()) {
347 	case -1:
348 		goto err;
349 
350 	case 0: { 		/* child */
351 		char *ex, *requri, *portno;
352 		char addr[NI_MAXHOST];
353 		char *argv[] = { NULL, NULL, NULL };
354 		int ec;
355 
356 		close(p[0]);
357 		if (dup2(p[1], 1) == -1)
358 			goto childerr;
359 
360 		if (inet_ntop(c->af, &c->addr, addr, sizeof(addr)) == NULL)
361 			goto childerr;
362 
363 		ec = getnameinfo((struct sockaddr*)&c->addr, sizeof(c->addr),
364 		    addr, sizeof(addr),
365 		    NULL, 0,
366 		    NI_NUMERICHOST | NI_NUMERICSERV);
367 		if (ec != 0)
368 			goto childerr;
369 
370 		if (asprintf(&portno, "%d", conf.port) == -1)
371 			goto childerr;
372 
373 		if (asprintf(&ex, "%s/%s", c->host->dir, spath) == -1)
374 			goto childerr;
375 
376 		if (asprintf(&requri, "%s%s%s", spath,
377 		    *relpath == '\0' ? "" : "/",
378 		    relpath) == -1)
379 			goto childerr;
380 
381 		argv[0] = argv[1] = ex;
382 
383 		/* fix the env */
384 		safe_setenv("GATEWAY_INTERFACE", "CGI/1.1");
385 		safe_setenv("SERVER_SOFTWARE", "gmid");
386 		safe_setenv("SERVER_PORT", portno);
387 		/* setenv("SERVER_NAME", "", 1); */
388 		safe_setenv("SCRIPT_NAME", spath);
389 		safe_setenv("SCRIPT_EXECUTABLE", ex);
390 		safe_setenv("REQUEST_URI", requri);
391 		safe_setenv("REQUEST_RELATIVE", relpath);
392 		safe_setenv("QUERY_STRING", query);
393 		safe_setenv("REMOTE_HOST", addr);
394 		safe_setenv("REMOTE_ADDR", addr);
395 		safe_setenv("DOCUMENT_ROOT", c->host->dir);
396 
397 		if (tls_peer_cert_provided(c->ctx)) {
398 			safe_setenv("AUTH_TYPE", "Certificate");
399 			safe_setenv("REMOTE_USER", tls_peer_cert_subject(c->ctx));
400 			safe_setenv("TLS_CLIENT_ISSUER", tls_peer_cert_issuer(c->ctx));
401 			safe_setenv("TLS_CLIENT_HASH", tls_peer_cert_hash(c->ctx));
402 		}
403 
404 		execvp(ex, argv);
405 		goto childerr;
406 	}
407 
408 	default:		/* parent */
409 		close(p[1]);
410 		close(c->fd);
411 		c->fd = p[0];
412 		c->child = pid;
413 		mark_nonblock(c->fd);
414 		c->state = S_SENDING;
415 		handle_cgi(fds, c);
416 		return 0;
417 	}
418 
419 err:
420 	if (!start_reply(fds, c, TEMP_FAILURE, "internal server error"))
421 		return 0;
422 	goodbye(fds, c);
423 	return 0;
424 
425 childerr:
426 	dprintf(p[1], "%d internal server error\r\n", TEMP_FAILURE);
427 	close(p[1]);
428 	_exit(1);
429 }
430 
431 void
432 cgi_poll_on_child(struct pollfd *fds, struct client *c)
433 {
434 	int fd;
435 
436 	if (c->waiting_on_child)
437 		return;
438 	c->waiting_on_child = 1;
439 
440 	fds->events = POLLIN;
441 
442 	fd = fds->fd;
443 	fds->fd = c->fd;
444 	c->fd = fd;
445 }
446 
447 void
448 cgi_poll_on_client(struct pollfd *fds, struct client *c)
449 {
450 	int fd;
451 
452 	if (!c->waiting_on_child)
453 		return;
454 	c->waiting_on_child = 0;
455 
456 	fd = fds->fd;
457 	fds->fd = c->fd;
458 	c->fd = fd;
459 }
460 
461 void
462 handle_cgi(struct pollfd *fds, struct client *c)
463 {
464 	ssize_t r;
465 
466 	/* ensure c->fd is the child and fds->fd the client */
467 	cgi_poll_on_client(fds, c);
468 
469 	while (1) {
470 		if (c->len == 0) {
471 			if ((r = read(c->fd, c->sbuf, sizeof(c->sbuf))) == 0)
472 				goto end;
473 			if (r == -1) {
474 				if (errno == EAGAIN || errno == EWOULDBLOCK) {
475 					cgi_poll_on_child(fds, c);
476 					return;
477 				}
478                                 goto end;
479 			}
480 			c->len = r;
481 			c->off = 0;
482 		}
483 
484 		while (c->len > 0) {
485 			switch (r = tls_write(c->ctx, c->sbuf + c->off, c->len)) {
486 			case -1:
487 				goto end;
488 
489 			case TLS_WANT_POLLOUT:
490 				fds->events = POLLOUT;
491 				return;
492 
493 			case TLS_WANT_POLLIN:
494 				fds->events = POLLIN;
495 				return;
496 
497 			default:
498                                 c->off += r;
499 				c->len -= r;
500 				break;
501 			}
502 		}
503 	}
504 
505 end:
506 	goodbye(fds, c);
507 }
508 
509 void
510 send_file(char *path, char *query, struct pollfd *fds, struct client *c)
511 {
512 	ssize_t ret, len;
513 
514 	if (c->fd == -1) {
515 		if (!open_file(path, query, fds, c))
516 			return;
517 		c->state = S_SENDING;
518 	}
519 
520 	len = (c->buf + c->len) - c->i;
521 
522 	while (len > 0) {
523 		switch (ret = tls_write(c->ctx, c->i, len)) {
524 		case -1:
525 			LOGE(c, "tls_write: %s", tls_error(c->ctx));
526 			goodbye(fds, c);
527 			return;
528 
529 		case TLS_WANT_POLLIN:
530 			fds->events = POLLIN;
531 			return;
532 
533 		case TLS_WANT_POLLOUT:
534 			fds->events = POLLOUT;
535 			return;
536 
537 		default:
538 			c->i += ret;
539 			len -= ret;
540 			break;
541 		}
542 	}
543 
544 	goodbye(fds, c);
545 }
546 
547 void
548 send_dir(char *path, struct pollfd *fds, struct client *client)
549 {
550 	char fpath[PATHBUF];
551 	size_t len;
552 
553 	bzero(fpath, PATHBUF);
554 
555 	if (path[0] != '.')
556 		fpath[0] = '.';
557 
558 	/* this cannot fail since sizeof(fpath) > maxlen of path */
559 	strlcat(fpath, path, PATHBUF);
560 	len = strlen(fpath);
561 
562 	/* add a trailing / in case. */
563 	if (fpath[len-1] != '/') {
564 		fpath[len] = '/';
565 	}
566 
567 	strlcat(fpath, "index.gmi", sizeof(fpath));
568 
569 	send_file(fpath, NULL, fds, client);
570 }
571 
572 void
573 handle_handshake(struct pollfd *fds, struct client *c)
574 {
575 	struct vhost *h;
576 	const char *servname;
577 
578 	switch (tls_handshake(c->ctx)) {
579 	case 0:  /* success */
580 	case -1: /* already handshaked */
581 		break;
582 	case TLS_WANT_POLLIN:
583 		fds->events = POLLIN;
584 		return;
585 	case TLS_WANT_POLLOUT:
586 		fds->events = POLLOUT;
587 		return;
588 	default:
589 		/* unreachable */
590 		abort();
591 	}
592 
593 	servname = tls_conn_servername(c->ctx);
594 	if (servname == NULL)
595 		goto wronghost;
596 
597 	for (h = hosts; h->domain != NULL; ++h) {
598 		if (!strcmp(h->domain, servname) || !strcmp(h->domain, "*"))
599 			break;
600 	}
601 
602 	if (h->domain != NULL) {
603 		c->state = S_OPEN;
604 		c->host = h;
605 		handle_open_conn(fds, c);
606 		return;
607 	}
608 
609 wronghost:
610 	/* XXX: check the correct response */
611 	if (!start_reply(fds, c, BAD_REQUEST, "Wrong host or missing SNI"))
612 		return;
613 	goodbye(fds, c);
614 }
615 
616 void
617 handle_open_conn(struct pollfd *fds, struct client *c)
618 {
619 	char buf[GEMINI_URL_LEN];
620 	const char *parse_err = "invalid request";
621 	struct iri iri;
622 
623 	bzero(buf, sizeof(buf));
624 
625 	switch (tls_read(c->ctx, buf, sizeof(buf)-1)) {
626 	case -1:
627 		LOGE(c, "tls_read: %s", tls_error(c->ctx));
628 		goodbye(fds, c);
629 		return;
630 
631 	case TLS_WANT_POLLIN:
632 		fds->events = POLLIN;
633 		return;
634 
635 	case TLS_WANT_POLLOUT:
636 		fds->events = POLLOUT;
637 		return;
638 	}
639 
640 	if (!trim_req_iri(buf) || !parse_iri(buf, &iri, &parse_err)) {
641 		if (!start_reply(fds, c, BAD_REQUEST, parse_err))
642 			return;
643 		goodbye(fds, c);
644 		return;
645 	}
646 
647 	if (strcmp(iri.schema, "gemini")) {
648 		if (!start_reply(fds, c, PROXY_REFUSED, "won't proxy request"))
649 			return;
650 		goodbye(fds, c);
651 		return;
652 	}
653 
654 	LOGI(c, "GET %s%s%s",
655 		*iri.path ? iri.path : "/",
656 		*iri.query ? "?" : "",
657 		*iri.query ? iri.query : "");
658 
659 	send_file(iri.path, iri.query, fds, c);
660 }
661 
662 void
663 handle(struct pollfd *fds, struct client *client)
664 {
665 	switch (client->state) {
666 	case S_HANDSHAKE:
667 		handle_handshake(fds, client);
668 		break;
669 
670 	case S_OPEN:
671                 handle_open_conn(fds, client);
672 		break;
673 
674 	case S_INITIALIZING:
675 		if (!start_reply(fds, client, client->code, client->meta))
676 			return;
677 
678 		if (client->code != SUCCESS) {
679 			/* we don't need a body */
680 			goodbye(fds, client);
681 			return;
682 		}
683 
684 		client->state = S_SENDING;
685 
686 		/* fallthrough */
687 
688 	case S_SENDING:
689 		if (client->child != -1)
690 			handle_cgi(fds, client);
691 		else
692 			send_file(NULL, NULL, fds, client);
693 		break;
694 
695 	case S_CLOSING:
696 		goodbye(fds, client);
697 		break;
698 
699 	default:
700 		/* unreachable */
701 		abort();
702 	}
703 }
704 
705 void
706 mark_nonblock(int fd)
707 {
708 	int flags;
709 
710 	if ((flags = fcntl(fd, F_GETFL)) == -1)
711 		fatal("fcntl(F_GETFL): %s", strerror(errno));
712 	if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1)
713 		fatal("fcntl(F_SETFL): %s", strerror(errno));
714 }
715 
716 int
717 make_socket(int port, int family)
718 {
719 	int sock, v;
720 	struct sockaddr_in addr4;
721 	struct sockaddr_in6 addr6;
722 	struct sockaddr *addr;
723 	socklen_t len;
724 
725         switch (family) {
726 	case AF_INET:
727 		bzero(&addr4, sizeof(addr4));
728 		addr4.sin_family = family;
729 		addr4.sin_port = htons(port);
730 		addr4.sin_addr.s_addr = INADDR_ANY;
731 		addr = (struct sockaddr*)&addr4;
732 		len = sizeof(addr4);
733 		break;
734 
735 	case AF_INET6:
736 		bzero(&addr6, sizeof(addr6));
737 		addr6.sin6_family = AF_INET6;
738 		addr6.sin6_port = htons(port);
739 		addr6.sin6_addr = in6addr_any;
740 		addr = (struct sockaddr*)&addr6;
741 		len = sizeof(addr6);
742 		break;
743 
744 	default:
745 		/* unreachable */
746 		abort();
747 	}
748 
749 	if ((sock = socket(family, SOCK_STREAM, 0)) == -1)
750 		fatal("socket: %s", strerror(errno));
751 
752 	v = 1;
753 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &v, sizeof(v)) == -1)
754 		fatal("setsockopt(SO_REUSEADDR): %s", strerror(errno));
755 
756 	v = 1;
757 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &v, sizeof(v)) == -1)
758 		fatal("setsockopt(SO_REUSEPORT): %s", strerror(errno));
759 
760 	mark_nonblock(sock);
761 
762 	if (bind(sock, addr, len) == -1)
763 		fatal("bind: %s", strerror(errno));
764 
765 	if (listen(sock, 16) == -1)
766 		fatal("listen: %s", strerror(errno));
767 
768 	return sock;
769 }
770 
771 void
772 do_accept(int sock, struct tls *ctx, struct pollfd *fds, struct client *clients)
773 {
774 	int i, fd;
775 	struct sockaddr_storage addr;
776 	socklen_t len;
777 
778 	len = sizeof(addr);
779 	if ((fd = accept(sock, (struct sockaddr*)&addr, &len)) == -1) {
780 		if (errno == EWOULDBLOCK)
781 			return;
782 		fatal("accept: %s", strerror(errno));
783 	}
784 
785 	mark_nonblock(fd);
786 
787 	for (i = 0; i < MAX_USERS; ++i) {
788 		if (fds[i].fd == -1) {
789 			bzero(&clients[i], sizeof(struct client));
790 			if (tls_accept_socket(ctx, &clients[i].ctx, fd) == -1)
791 				break; /* goodbye fd! */
792 
793 			fds[i].fd = fd;
794 			fds[i].events = POLLIN;
795 
796 			clients[i].state = S_HANDSHAKE;
797 			clients[i].fd = -1;
798 			clients[i].child = -1;
799 			clients[i].buf = MAP_FAILED;
800 			clients[i].af = AF_INET;
801 			clients[i].addr = addr;
802 
803 			connected_clients++;
804 			return;
805 		}
806 	}
807 
808 	close(fd);
809 }
810 
811 void
812 goodbye(struct pollfd *pfd, struct client *c)
813 {
814 	ssize_t ret;
815 
816 	c->state = S_CLOSING;
817 
818 	ret = tls_close(c->ctx);
819 	if (ret == TLS_WANT_POLLIN) {
820 		pfd->events = POLLIN;
821 		return;
822 	}
823 	if (ret == TLS_WANT_POLLOUT) {
824 		pfd->events = POLLOUT;
825 		return;
826 	}
827 
828 	connected_clients--;
829 
830 	tls_free(c->ctx);
831 	c->ctx = NULL;
832 
833 	if (c->buf != MAP_FAILED)
834 		munmap(c->buf, c->len);
835 
836 	if (c->fd != -1)
837 		close(c->fd);
838 
839 	close(pfd->fd);
840 	pfd->fd = -1;
841 }
842 
843 void
844 loop(struct tls *ctx, int sock4, int sock6)
845 {
846 	int i;
847 	struct client clients[MAX_USERS];
848 	struct pollfd fds[MAX_USERS];
849 
850 	for (i = 0; i < MAX_USERS; ++i) {
851 		fds[i].fd = -1;
852 		fds[i].events = POLLIN;
853 		bzero(&clients[i], sizeof(struct client));
854 	}
855 
856 	fds[0].fd = sock4;
857 	fds[1].fd = sock6;
858 
859 	for (;;) {
860 		if (poll(fds, MAX_USERS, INFTIM) == -1) {
861 			if (errno == EINTR) {
862                                 warnx("connected clients: %d",
863 				    connected_clients);
864 				continue;
865 			}
866 			fatal("poll: %s", strerror(errno));
867 		}
868 
869 		for (i = 0; i < MAX_USERS; i++) {
870 			if (fds[i].revents == 0)
871 				continue;
872 
873 			if (fds[i].revents & (POLLERR|POLLNVAL))
874 				fatal("bad fd %d: %s", fds[i].fd,
875 				    strerror(errno));
876 
877 			if (fds[i].revents & POLLHUP) {
878 				/* fds[i] may be the fd of the stdin
879 				 * of a cgi script that has exited. */
880 				if (!clients[i].waiting_on_child) {
881 					goodbye(&fds[i], &clients[i]);
882 					continue;
883 				}
884 			}
885 
886 			if (fds[i].fd == sock4)
887 				do_accept(sock4, ctx, fds, clients);
888 			else if (fds[i].fd == sock6)
889 				do_accept(sock6, ctx, fds, clients);
890 			else
891 				handle(&fds[i], &clients[i]);
892 		}
893 	}
894 }
895 
896 char *
897 absolutify_path(const char *path)
898 {
899 	char *wd, *r;
900 
901 	if (*path == '/')
902 		return strdup(path);
903 
904 	wd = getwd(NULL);
905 	if (asprintf(&r, "%s/%s", wd, path) == -1)
906 		err(1, "asprintf");
907 	free(wd);
908 	return r;
909 }
910 
911 void
912 yyerror(const char *msg)
913 {
914 	goterror = 1;
915 	fprintf(stderr, "%d: %s\n", yylineno, msg);
916 }
917 
918 int
919 parse_portno(const char *p)
920 {
921 	char *ep;
922 	long lval;
923 
924 	errno = 0;
925 	lval = strtol(p, &ep, 10);
926 	if (p[0] == '\0' || *ep != '\0')
927 		errx(1, "not a number: %s", p);
928 	if (lval < 0 || lval > UINT16_MAX)
929 		errx(1, "port number out of range for domain %s: %ld", p, lval);
930 	return lval;
931 }
932 
933 void
934 parse_conf(const char *path)
935 {
936 	if ((yyin = fopen(path, "r")) == NULL)
937 		err(1, "cannot open config %s", path);
938 	yyparse();
939 	fclose(yyin);
940 
941 	if (goterror)
942 		exit(1);
943 }
944 
945 void
946 load_vhosts(struct tls_config *tlsconf)
947 {
948 	struct vhost *h;
949 
950 	/* we need to set something, then we can add how many key we want */
951 	if (tls_config_set_keypair_file(tlsconf, hosts->cert, hosts->key))
952 		errx(1, "tls_config_set_keypair_file failed");
953 
954 	for (h = hosts; h->domain != NULL; ++h) {
955 		if (tls_config_add_keypair_file(tlsconf, h->cert, h->key) == -1)
956 			errx(1, "failed to load the keypair (%s, %s)",
957 			    h->cert, h->key);
958 
959 		if ((h->dirfd = open(h->dir, O_RDONLY | O_DIRECTORY)) == -1)
960 			err(1, "open %s for domain %s", h->dir, h->domain);
961 	}
962 }
963 
964 /* we can augment this function to handle also capsicum and seccomp eventually */
965 void
966 sandbox()
967 {
968         struct vhost *h;
969 	int has_cgi = 0;
970 
971 	for (h = hosts; h->domain != NULL; ++h) {
972 		if (unveil(h->dir, "rx") == -1)
973 			err(1, "unveil %s for domain %s", h->dir, h->domain);
974 
975 		if (h->cgi != NULL)
976 			has_cgi = 1;
977 	}
978 
979 	if (pledge("stdio rpath inet proc exec", NULL) == -1)
980 		err(1, "pledge");
981 
982 	/* drop proc and exec if cgi isn't enabled */
983 	if (!has_cgi)
984 		if (pledge("stdio rpath inet", NULL) == -1)
985 			err(1, "pledge");
986 }
987 
988 void
989 usage(const char *me)
990 {
991 	fprintf(stderr,
992 	    "USAGE: %s [-n] [-c config] | [-6fh] [-C cert] [-d root] [-K key] "
993 	    "[-p port] [-x cgi-bin]\n",
994 	    me);
995 }
996 
997 int
998 main(int argc, char **argv)
999 {
1000 	struct tls *ctx = NULL;
1001 	struct tls_config *tlsconf;
1002 	int sock4, sock6, ch;
1003 	const char *config_path = NULL;
1004 	size_t i;
1005 	int conftest = 0, has_cgi = 0;
1006 
1007 	bzero(hosts, sizeof(hosts));
1008 	for (i = 0; i < HOSTSLEN; ++i)
1009 		hosts[i].dirfd = -1;
1010 
1011 	conf.foreground = 1;
1012 	conf.port = 1965;
1013 	conf.ipv6 = 0;
1014 
1015 	connected_clients = 0;
1016 
1017 	while ((ch = getopt(argc, argv, "6C:c:d:fhK:np:x:")) != -1) {
1018 		switch (ch) {
1019 		case '6':
1020 			conf.ipv6 = 1;
1021 			break;
1022 
1023 		case 'C':
1024 			hosts[0].cert = optarg;
1025 			break;
1026 
1027 		case 'c':
1028 			config_path = optarg;
1029 			break;
1030 
1031 		case 'd':
1032 			free((char*)hosts[0].dir);
1033 			if ((hosts[0].dir = absolutify_path(optarg)) == NULL)
1034 				err(1, "absolutify_path");
1035 			break;
1036 
1037 		case 'f':
1038 			conf.foreground = 1;
1039 			break;
1040 
1041 		case 'h':
1042 			usage(*argv);
1043 			return 0;
1044 
1045 		case 'K':
1046 			hosts[0].key = optarg;
1047 			break;
1048 
1049 		case 'n':
1050 			conftest = 1;
1051 			break;
1052 
1053 		case 'p':
1054 			conf.port = parse_portno(optarg);
1055 
1056 		case 'x':
1057 			/* drop the starting / (if any) */
1058 			if (*optarg == '/')
1059 				optarg++;
1060 			hosts[0].cgi = optarg;
1061 			break;
1062 
1063 		default:
1064 			usage(*argv);
1065 			return 1;
1066 		}
1067 	}
1068 
1069 	if (config_path != NULL) {
1070 		if (hosts[0].cert != NULL || hosts[0].key != NULL ||
1071 		    hosts[0].dir != NULL)
1072 			errx(1, "can't specify options in conf mode");
1073 		parse_conf(config_path);
1074 	} else {
1075 		if (hosts[0].cert == NULL || hosts[0].key == NULL ||
1076 		    hosts[0].dir == NULL)
1077 			errx(1, "missing cert, key or root directory to serve");
1078 		hosts[0].domain = "*";
1079 	}
1080 
1081 	if (conftest)
1082                 errx(0, "config OK");
1083 
1084 	signal(SIGPIPE, SIG_IGN);
1085 	signal(SIGCHLD, SIG_IGN);
1086 
1087 #ifdef SIGINFO
1088 	signal(SIGINFO, sig_handler);
1089 #endif
1090 	signal(SIGUSR2, sig_handler);
1091 
1092 	if (!conf.foreground)
1093 		signal(SIGHUP, SIG_IGN);
1094 
1095 	if ((tlsconf = tls_config_new()) == NULL)
1096 		err(1, "tls_config_new");
1097 
1098 	/* optionally accept client certs, but don't try to verify them */
1099 	tls_config_verify_client_optional(tlsconf);
1100 	tls_config_insecure_noverifycert(tlsconf);
1101 
1102 	if (tls_config_set_protocols(tlsconf,
1103 	    TLS_PROTOCOL_TLSv1_2 | TLS_PROTOCOL_TLSv1_3) == -1)
1104 		err(1, "tls_config_set_protocols");
1105 
1106 	load_vhosts(tlsconf);
1107 
1108 	if ((ctx = tls_server()) == NULL)
1109 		err(1, "tls_server");
1110 
1111 	if (tls_configure(ctx, tlsconf) == -1)
1112 		errx(1, "tls_configure: %s", tls_error(ctx));
1113 
1114 	sock4 = make_socket(conf.port, AF_INET);
1115 	if (conf.ipv6)
1116 		sock6 = make_socket(conf.port, AF_INET6);
1117 	else
1118 		sock6 = -1;
1119 
1120 
1121 	if (!conf.foreground && daemon(0, 1) == -1)
1122 		exit(1);
1123 
1124 	sandbox();
1125 
1126 	loop(ctx, sock4, sock6);
1127 
1128 	close(sock4);
1129 	close(sock6);
1130 	tls_free(ctx);
1131 	tls_config_free(tlsconf);
1132 
1133 	return 0;
1134 }