op public repos

Blob

Date:: Thu Nov 5 16:05:28 2020 UTC
Message:: define a MIME type for xml files
Actions:: History | Blame | Raw File
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 <netinet/in.h>
22 
23 #include <assert.h>
24 #include <err.h>
25 #include <errno.h>
26 #include <fcntl.h>
27 #include <poll.h>
28 #include <signal.h>
29 #include <stdio.h>
30 #include <stdlib.h>
31 #include <string.h>
32 #include <tls.h>
33 #include <unistd.h>
34 
35 #ifndef __OpenBSD__
36 # define pledge(a, b) 0
37 # define unveil(a, b) 0
38 #endif /* __OpenBSD__ */
39 
40 #ifndef INFTIM
41 # define INFTIM -1
42 #endif /* INFTIM */
43 
44 #define GEMINI_URL_LEN (1024+3)	/* URL max len + \r\n + \0 */
45 
46 /* large enough to hold a copy of a gemini URL and still have extra room */
47 #define PATHBUF		2048
48 
49 #define SUCCESS		20
50 #define NOT_FOUND	51
51 #define BAD_REQUEST	59
52 
53 #ifndef MAX_USERS
54 #define MAX_USERS	64
55 #endif
56 
57 enum {
58 	S_OPEN,
59 	S_INITIALIZING,
60 	S_SENDING,
61 	S_CLOSING,
62 };
63 
64 struct client {
65 	struct tls	*ctx;
66 	int		 state;
67 	int		 code;
68 	const char	*meta;
69 	int		 fd;
70 	void		*buf, *i;
71 	ssize_t		 len, off;
72 };
73 
74 struct etm {			/* file extension to mime */
75 	const char	*mime;
76 	const char	*ext;
77 } filetypes[] = {
78 	{"application/pdf",	"pdf"},
79 
80 	{"image/gif",		"gif"},
81 	{"image/jpeg",		"jpg"},
82 	{"image/jpeg",		"jpeg"},
83 	{"image/png",		"png"},
84 	{"image/svg+xml",	"svg"},
85 
86 	{"text/gemini",		"gemini"},
87 	{"text/gemini",		"gmi"},
88 	{"text/markdown",	"markdown"},
89 	{"text/markdown",	"md"},
90 	{"text/plain",		"txt"},
91 	{"text/xml",		"xml"}
92 
93 	{NULL, NULL}
94 };
95 
96 int dirfd;
97 
98 char		*url_after_proto(char*);
99 char		*url_start_of_request(char*);
100 int		 url_trim(char*);
101 void		 adjust_path(char*);
102 int		 path_isdir(char*);
103 ssize_t		 filesize(int);
104 
105 int		 start_reply(struct pollfd*, struct client*, int, const char*);
106 int		 isdir(int);
107 const char	*path_ext(const char*);
108 const char	*mime(const char*);
109 int		 open_file(char*, struct pollfd*, struct client*);
110 void		 send_file(char*, struct pollfd*, struct client*);
111 void		 send_dir(char*, struct pollfd*, struct client*);
112 void		 handle(struct pollfd*, struct client*);
113 
114 void		 mark_nonblock(int);
115 int		 make_soket(int);
116 void		 do_accept(int, struct tls*, struct pollfd*, struct client*);
117 void		 goodbye(struct pollfd*, struct client*);
118 void		 loop(struct tls*, int);
119 
120 void		 usage(const char*);
121 
122 char *
123 url_after_proto(char *url)
124 {
125 	char *s;
126 	const char *proto = "gemini";
127 	const char *marker = "://";
128 
129 	if ((s = strstr(url, marker)) == NULL)
130 		return url;
131 
132 	/* not a gemini:// URL */
133 
134 	if (s - strlen(proto) < url)
135 		return NULL;
136 	/* TODO: */
137 	/* if (strcmp(s - strlen(proto), proto)) */
138 	/* 	return NULL; */
139 
140 	/* a valid gemini:// URL */
141 	return s + strlen(marker);
142 }
143 
144 char *
145 url_start_of_request(char *url)
146 {
147 	char *s, *t;
148 
149 	if ((s = url_after_proto(url)) == NULL)
150 		return NULL;
151 
152 	if ((t = strstr(s, "/")) == NULL)
153 		return s + strlen(s);
154 	return t;
155 }
156 
157 int
158 url_trim(char *url)
159 {
160 	const char *e = "\r\n";
161 	char *s;
162 
163 	if ((s = strstr(url, e)) == NULL)
164 		return 0;
165 	s[0] = '\0';
166 	s[1] = '\0';
167 
168 	if (s[2] != '\0') {
169 		fprintf(stderr, "the request was longer than 1024 bytes\n");
170 		return 0;
171 	}
172 
173 	return 1;
174 }
175 
176 void
177 adjust_path(char *path)
178 {
179 	char *s;
180 	size_t len;
181 
182 	/* /.. -> / */
183 	len = strlen(path);
184 	if (len >= 3) {
185 		if (!strcmp(&path[len-3], "/..")) {
186 			path[len-2] = '\0';
187 		}
188 	}
189 
190 	/* if the path is only `..` trim out and exit */
191 	if (!strcmp(path, "..")) {
192 		path[0] = '\0';
193 		return;
194 	}
195 
196 	/* remove every ../ in the path */
197 	while (1) {
198 		if ((s = strstr(path, "../")) == NULL)
199 			return;
200 		memmove(s, s+3, strlen(s)+1);	/* copy also the \0 */
201 	}
202 }
203 
204 int
205 path_isdir(char *path)
206 {
207 	if (*path == '\0')
208 		return 1;
209 	return path[strlen(path)-1] == '/';
210 }
211 
212 int
213 start_reply(struct pollfd *pfd, struct client *client, int code, const char *reason)
214 {
215 	char buf[1030] = {0}; 	/* status + ' ' + max reply len + \r\n\0 */
216 	int len;
217 	int ret;
218 
219 	client->code = code;
220 	client->meta = reason;
221 	client->state = S_INITIALIZING;
222 
223 	len = snprintf(buf, sizeof(buf), "%d %s\r\n", code, reason);
224 	assert(len < (int)sizeof(buf));
225 	ret = tls_write(client->ctx, buf, len);
226 	if (ret == TLS_WANT_POLLIN) {
227 		pfd->events = POLLIN;
228 		return 0;
229 	}
230 
231 	if (ret == TLS_WANT_POLLOUT) {
232 		pfd->events = POLLOUT;
233 		return 0;
234 	}
235 
236 	return 1;
237 }
238 
239 int
240 isdir(int fd)
241 {
242 	struct stat sb;
243 
244 	if (fstat(fd, &sb) == -1) {
245 		warn("fstat");
246 		return 1; 	/* we'll probably fail later on anyway */
247 	}
248 
249 	return S_ISDIR(sb.st_mode);
250 }
251 
252 ssize_t
253 filesize(int fd)
254 {
255 	ssize_t len;
256 
257 	if ((len = lseek(fd, 0, SEEK_END)) == -1)
258 		return -1;
259 	if (lseek(fd, 0, SEEK_SET) == -1)
260 		return -1;
261 	return len;
262 }
263 
264 const char *
265 path_ext(const char *path)
266 {
267 	const char *end;
268 
269 	end = path + strlen(path)-1; /* the last byte before the NUL */
270 	for (; end != path; --end) {
271 		if (*end == '.')
272 			return end+1;
273 		if (*end == '/')
274 			break;
275 	}
276 
277 	return NULL;
278 }
279 
280 const char *
281 mime(const char *path)
282 {
283 	const char *ext, *def = "application/octet-stream";
284 	struct etm *t;
285 
286 	if ((ext = path_ext(path)) == NULL)
287 		return def;
288 
289 	for (t = filetypes; t->mime != NULL; ++t)
290 		if (!strcmp(ext, t->ext))
291 			return t->mime;
292 
293 	return def;
294 }
295 
296 int
297 open_file(char *path, struct pollfd *fds, struct client *c)
298 {
299 	char fpath[PATHBUF];
300 
301 	assert(path != NULL);
302 
303 	bzero(fpath, sizeof(fpath));
304 
305 	if (*path != '.')
306 		fpath[0] = '.';
307 	strlcat(fpath, path, PATHBUF);
308 
309 	if ((c->fd = openat(dirfd, fpath, O_RDONLY | O_NOFOLLOW)) == -1) {
310 		warn("open: %s", fpath);
311 		if (!start_reply(fds, c, NOT_FOUND, "not found"))
312 			return 0;
313 		goodbye(fds, c);
314 		return 0;
315 	}
316 
317 	if (isdir(c->fd)) {
318 		warnx("%s is a directory, trying %s/index.gmi", fpath, fpath);
319 		close(c->fd);
320 		c->fd = -1;
321 		send_dir(fpath, fds, c);
322 		return 0;
323 	}
324 
325 	if ((c->len = filesize(c->fd)) == -1) {
326 		warn("filesize: %s", fpath);
327 		goodbye(fds, c);
328 		return 0;
329 	}
330 
331 	if ((c->buf = mmap(NULL, c->len, PROT_READ, MAP_PRIVATE,
332 		    c->fd, 0)) == MAP_FAILED) {
333 		warn("mmap: %s", fpath);
334 		goodbye(fds, c);
335 		return 0;
336 	}
337 	c->i = c->buf;
338 
339 	return start_reply(fds, c, SUCCESS, mime(fpath));
340 }
341 
342 void
343 send_file(char *path, struct pollfd *fds, struct client *c)
344 {
345 	ssize_t ret, len;
346 
347 	if (c->fd == -1) {
348 		if (!open_file(path, fds, c))
349 			return;
350 		c->state = S_SENDING;
351 	}
352 
353 	len = (c->buf + c->len) - c->i;
354 
355 	while (len > 0) {
356 		switch (ret = tls_write(c->ctx, c->i, len)) {
357 		case -1:
358 			warnx("tls_write: %s", tls_error(c->ctx));
359 			goodbye(fds, c);
360 			return;
361 
362 		case TLS_WANT_POLLIN:
363 			fds->events = POLLIN;
364 			return;
365 
366 		case TLS_WANT_POLLOUT:
367 			fds->events = POLLOUT;
368 			return;
369 
370 		default:
371 			c->i += ret;
372 			len -= ret;
373 			break;
374 		}
375 	}
376 
377 	goodbye(fds, c);
378 }
379 
380 void
381 send_dir(char *path, struct pollfd *fds, struct client *client)
382 {
383 	char fpath[PATHBUF];
384 	size_t len;
385 
386 	bzero(fpath, PATHBUF);
387 
388 	if (path[0] != '.')
389 		fpath[0] = '.';
390 
391 	/* this cannot fail since sizeof(fpath) > maxlen of path */
392 	strlcat(fpath, path, PATHBUF);
393 	len = strlen(fpath);
394 
395 	/* add a trailing / in case. */
396 	if (fpath[len-1] != '/') {
397 		fpath[len] = '/';
398 	}
399 
400 	strlcat(fpath, "index.gmi", sizeof(fpath));
401 
402 	send_file(fpath, fds, client);
403 }
404 
405 void
406 handle(struct pollfd *fds, struct client *client)
407 {
408 	char buf[GEMINI_URL_LEN];
409 	char *path;
410 
411 	switch (client->state) {
412 	case S_OPEN:
413 		bzero(buf, GEMINI_URL_LEN);
414 		switch (tls_read(client->ctx, buf, sizeof(buf)-1)) {
415 		case -1:
416 			warnx("tls_read: %s", tls_error(client->ctx));
417 			goodbye(fds, client);
418 			return;
419 
420 		case TLS_WANT_POLLIN:
421 			fds->events = POLLIN;
422 			return;
423 
424 		case TLS_WANT_POLLOUT:
425 			fds->events = POLLOUT;
426 			return;
427 		}
428 
429 		if (!url_trim(buf)) {
430 			if (!start_reply(fds, client, BAD_REQUEST, "bad request"))
431 				return;
432 			goodbye(fds, client);
433 			return;
434 		}
435 
436 		if ((path = url_start_of_request(buf)) == NULL) {
437 			if (!start_reply(fds, client, BAD_REQUEST, "bad request"))
438 				return;
439 			goodbye(fds, client);
440 			return;
441 		}
442 
443 		adjust_path(path);
444 		fprintf(stderr, "requested path: %s\n", path);
445 
446 		if (path_isdir(path))
447 			send_dir(path, fds, client);
448 		else
449 			send_file(path, fds, client);
450 		break;
451 
452 	case S_INITIALIZING:
453 		if (!start_reply(fds, client, client->code, client->meta))
454 			return;
455 
456 		if (client->code != SUCCESS) {
457 			/* we don't need a body */
458 			goodbye(fds, client);
459 			return;
460 		}
461 
462 		client->state = S_SENDING;
463 
464 		/* fallthrough */
465 
466 	case S_SENDING:
467 		send_file(NULL, fds, client);
468 		break;
469 
470 	case S_CLOSING:
471 		goodbye(fds, client);
472 		break;
473 
474 	default:
475 		/* unreachable */
476 		abort();
477 	}
478 }
479 
480 void
481 mark_nonblock(int fd)
482 {
483 	int flags;
484 
485 	if ((flags = fcntl(fd, F_GETFL)) == -1)
486 		err(1, "fcntl(F_GETFL)");
487 	if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1)
488 		err(1, "fcntl(F_SETFL)");
489 }
490 
491 int
492 make_socket(int port, int family)
493 {
494 	int sock, v;
495 	struct sockaddr_in addr4;
496 	struct sockaddr_in6 addr6;
497 	struct sockaddr *addr;
498 	socklen_t len;
499 
500         switch (family) {
501 	case AF_INET:
502 		bzero(&addr4, sizeof(addr4));
503 		addr4.sin_family = family;
504 		addr4.sin_port = htons(port);
505 		addr4.sin_addr.s_addr = INADDR_ANY;
506 		addr = (struct sockaddr*)&addr4;
507 		len = sizeof(addr4);
508 		break;
509 
510 	case AF_INET6:
511 		bzero(&addr6, sizeof(addr6));
512 		addr6.sin6_family = AF_INET6;
513 		addr6.sin6_port = htons(port);
514 		addr6.sin6_addr = in6addr_any;
515 		addr = (struct sockaddr*)&addr6;
516 		len = sizeof(addr6);
517 		break;
518 
519 	default:
520 		/* unreachable */
521 		abort();
522 	}
523 
524 	if ((sock = socket(family, SOCK_STREAM, 0)) == -1)
525 		err(1, "socket");
526 
527 	v = 1;
528 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &v, sizeof(v)) == -1)
529 		err(1, "setsockopt(SO_REUSEADDR)");
530 
531 	v = 1;
532 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &v, sizeof(v)) == -1)
533 		err(1, "setsockopt(SO_REUSEPORT)");
534 
535 	mark_nonblock(sock);
536 
537 	if (bind(sock, addr, len) == -1)
538 		err(1, "bind");
539 
540 	if (listen(sock, 16) == -1)
541 		err(1, "listen");
542 
543 	return sock;
544 }
545 
546 void
547 do_accept(int sock, struct tls *ctx, struct pollfd *fds, struct client *clients)
548 {
549 	int i, fd;
550 	struct sockaddr_in addr;
551 	socklen_t len;
552 
553 	len = sizeof(addr);
554 	if ((fd = accept(sock, (struct sockaddr*)&addr, &len)) == -1) {
555 		if (errno == EWOULDBLOCK)
556 			return;
557 		err(1, "accept");
558 	}
559 
560 	mark_nonblock(fd);
561 
562 	for (i = 0; i < MAX_USERS; ++i) {
563 		if (fds[i].fd == -1) {
564 			bzero(&clients[i], sizeof(struct client));
565 			if (tls_accept_socket(ctx, &clients[i].ctx, fd) == -1)
566 				break; /* goodbye fd! */
567 
568 			fds[i].fd = fd;
569 			fds[i].events = POLLIN;
570 
571 			clients[i].state = S_OPEN;
572 			clients[i].fd = -1;
573 			clients[i].buf = MAP_FAILED;
574 
575 			return;
576 		}
577 	}
578 
579 	close(fd);
580 }
581 
582 void
583 goodbye(struct pollfd *pfd, struct client *c)
584 {
585 	ssize_t ret;
586 
587 	c->state = S_CLOSING;
588 
589 	ret = tls_close(c->ctx);
590 	if (ret == TLS_WANT_POLLIN) {
591 		pfd->events = POLLIN;
592 		return;
593 	}
594 	if (ret == TLS_WANT_POLLOUT) {
595 		pfd->events = POLLOUT;
596 		return;
597 	}
598 
599 	tls_free(c->ctx);
600 	c->ctx = NULL;
601 
602 	if (c->buf != MAP_FAILED)
603 		munmap(c->buf, c->len);
604 
605 	if (c->fd != -1)
606 		close(c->fd);
607 
608 	close(pfd->fd);
609 	pfd->fd = -1;
610 }
611 
612 void
613 loop(struct tls *ctx, int sock)
614 {
615 	int i, todo;
616 	struct client clients[MAX_USERS];
617 	struct pollfd fds[MAX_USERS];
618 
619 	for (i = 0; i < MAX_USERS; ++i) {
620 		fds[i].fd = -1;
621 		fds[i].events = POLLIN;
622 		bzero(&clients[i], sizeof(struct client));
623 	}
624 
625 	fds[0].fd = sock;
626 
627 	for (;;) {
628 		if ((todo = poll(fds, MAX_USERS, INFTIM)) == -1)
629 			err(1, "poll");
630 
631 		for (i = 0; i < MAX_USERS; i++) {
632 			assert(i < MAX_USERS);
633 
634 			if (fds[i].revents == 0)
635 				continue;
636 
637 			if (fds[i].revents & (POLLERR|POLLNVAL))
638 				err(1, "bad fd %d", fds[i].fd);
639 
640 			if (fds[i].revents & POLLHUP) {
641 				goodbye(&fds[i], &clients[i]);
642 				continue;
643 			}
644 
645 			todo--;
646 
647 			if (i == 0) { /* new client */
648 				do_accept(sock, ctx, fds, clients);
649 				continue;
650 			}
651 
652 			handle(&fds[i], &clients[i]);
653 		}
654 	}
655 }
656 
657 void
658 usage(const char *me)
659 {
660 	fprintf(stderr,
661 	    "USAGE: %s [-h] [-c cert.pem] [-d docs] [-k key.pem]\n",
662 	    me);
663 }
664 
665 int
666 main(int argc, char **argv)
667 {
668 	const char *cert = "cert.pem", *key = "key.pem", *dir = "docs";
669 	struct tls *ctx = NULL;
670 	struct tls_config *conf;
671 	int sock, ch;
672 
673 	signal(SIGPIPE, SIG_IGN);
674 
675 	while ((ch = getopt(argc, argv, "c:d:hk:")) != -1) {
676 		switch (ch) {
677 		case 'c':
678 			cert = optarg;
679 			break;
680 
681 		case 'd':
682 			dir = optarg;
683 			break;
684 
685 		case 'h':
686 			usage(*argv);
687 			return 0;
688 
689 		case 'k':
690 			key = optarg;
691 			break;
692 
693 		default:
694 			usage(*argv);
695 			return 1;
696 		}
697 	}
698 
699 	if ((conf = tls_config_new()) == NULL)
700 		err(1, "tls_config_new");
701 
702 	if (tls_config_set_protocols(conf,
703 	    TLS_PROTOCOL_TLSv1_2 | TLS_PROTOCOL_TLSv1_3) == -1)
704 		err(1, "tls_config_set_protocols");
705 
706 	if (tls_config_set_cert_file(conf, cert) == -1)
707 		err(1, "tls_config_set_cert_file: %s", cert);
708 
709 	if (tls_config_set_key_file(conf, key) == -1)
710 		err(1, "tls_config_set_key_file: %s", key);
711 
712 	if ((ctx = tls_server()) == NULL)
713 		err(1, "tls_server");
714 
715 	if (tls_configure(ctx, conf) == -1)
716 		errx(1, "tls_configure: %s", tls_error(ctx));
717 
718 	sock = make_socket(1965, AF_INET);
719 
720 	if ((dirfd = open(dir, O_RDONLY | O_DIRECTORY)) == -1)
721 		err(1, "open: %s", dir);
722 
723 	if (unveil(dir, "r") == -1)
724 		err(1, "unveil");
725 
726 	if (pledge("stdio rpath inet", "") == -1)
727 		err(1, "pledge");
728 
729 	loop(ctx, sock);
730 
731 	close(sock);
732 	tls_free(ctx);
733 	tls_config_free(conf);
734 }