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Date:: Fri Nov 6 09:58:30 2020 UTC
Message:: added option to log to a file
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 <arpa/inet.h>
22 #include <netinet/in.h>
23 
24 #include <assert.h>
25 #include <err.h>
26 #include <errno.h>
27 #include <fcntl.h>
28 #include <poll.h>
29 #include <signal.h>
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include <tls.h>
34 #include <unistd.h>
35 
36 #ifndef __OpenBSD__
37 # define pledge(a, b) 0
38 # define unveil(a, b) 0
39 #endif /* __OpenBSD__ */
40 
41 #ifndef INFTIM
42 # define INFTIM -1
43 #endif /* INFTIM */
44 
45 #define GEMINI_URL_LEN (1024+3)	/* URL max len + \r\n + \0 */
46 
47 /* large enough to hold a copy of a gemini URL and still have extra room */
48 #define PATHBUF		2048
49 
50 #define SUCCESS		20
51 #define NOT_FOUND	51
52 #define BAD_REQUEST	59
53 
54 #ifndef MAX_USERS
55 #define MAX_USERS	64
56 #endif
57 
58 enum {
59 	S_OPEN,
60 	S_INITIALIZING,
61 	S_SENDING,
62 	S_CLOSING,
63 };
64 
65 struct client {
66 	struct tls	*ctx;
67 	int		 state;
68 	int		 code;
69 	const char	*meta;
70 	int		 fd;
71 	void		*buf, *i;
72 	ssize_t		 len, off;
73 	int		 af;
74 	struct in_addr	 addr;
75 };
76 
77 struct etm {			/* file extension to mime */
78 	const char	*mime;
79 	const char	*ext;
80 } filetypes[] = {
81 	{"application/pdf",	"pdf"},
82 
83 	{"image/gif",		"gif"},
84 	{"image/jpeg",		"jpg"},
85 	{"image/jpeg",		"jpeg"},
86 	{"image/png",		"png"},
87 	{"image/svg+xml",	"svg"},
88 
89 	{"text/gemini",		"gemini"},
90 	{"text/gemini",		"gmi"},
91 	{"text/markdown",	"markdown"},
92 	{"text/markdown",	"md"},
93 	{"text/plain",		"txt"},
94 	{"text/xml",		"xml"},
95 
96 	{NULL, NULL}
97 };
98 
99 #define LOG(c, fmt, ...)						\
100 	do {								\
101 		char buf[INET_ADDRSTRLEN];				\
102 		if (inet_ntop((c)->af, &(c)->addr, buf, sizeof(buf)) == NULL) \
103 			err(1, "inet_ntop");				\
104 		dprintf(logfd, "[%s] " fmt "\n", buf, __VA_ARGS__);	\
105 	} while (0)
106 
107 int dirfd, logfd;
108 
109 char		*url_after_proto(char*);
110 char		*url_start_of_request(char*);
111 int		 url_trim(struct client*, char*);
112 void		 adjust_path(char*);
113 int		 path_isdir(char*);
114 ssize_t		 filesize(int);
115 
116 int		 start_reply(struct pollfd*, struct client*, int, const char*);
117 int		 isdir(int);
118 const char	*path_ext(const char*);
119 const char	*mime(const char*);
120 int		 open_file(char*, struct pollfd*, struct client*);
121 void		 send_file(char*, struct pollfd*, struct client*);
122 void		 send_dir(char*, struct pollfd*, struct client*);
123 void		 handle(struct pollfd*, struct client*);
124 
125 void		 mark_nonblock(int);
126 int		 make_soket(int);
127 void		 do_accept(int, struct tls*, struct pollfd*, struct client*);
128 void		 goodbye(struct pollfd*, struct client*);
129 void		 loop(struct tls*, int);
130 
131 void		 usage(const char*);
132 
133 char *
134 url_after_proto(char *url)
135 {
136 	char *s;
137 	const char *proto = "gemini";
138 	const char *marker = "://";
139 
140 	if ((s = strstr(url, marker)) == NULL)
141 		return url;
142 
143 	/* not a gemini:// URL */
144 
145 	if (s - strlen(proto) < url)
146 		return NULL;
147 	/* TODO: */
148 	/* if (strcmp(s - strlen(proto), proto)) */
149 	/* 	return NULL; */
150 
151 	/* a valid gemini:// URL */
152 	return s + strlen(marker);
153 }
154 
155 char *
156 url_start_of_request(char *url)
157 {
158 	char *s, *t;
159 
160 	if ((s = url_after_proto(url)) == NULL)
161 		return NULL;
162 
163 	if ((t = strstr(s, "/")) == NULL)
164 		return s + strlen(s);
165 	return t;
166 }
167 
168 int
169 url_trim(struct client *c, char *url)
170 {
171 	const char *e = "\r\n";
172 	char *s;
173 
174 	if ((s = strstr(url, e)) == NULL)
175 		return 0;
176 	s[0] = '\0';
177 	s[1] = '\0';
178 
179 	if (s[2] != '\0') {
180 		LOG(c, "%s", "request longer than 1024 bytes\n");
181 		return 0;
182 	}
183 
184 	return 1;
185 }
186 
187 void
188 adjust_path(char *path)
189 {
190 	char *s;
191 	size_t len;
192 
193 	/* /.. -> / */
194 	len = strlen(path);
195 	if (len >= 3) {
196 		if (!strcmp(&path[len-3], "/..")) {
197 			path[len-2] = '\0';
198 		}
199 	}
200 
201 	/* if the path is only `..` trim out and exit */
202 	if (!strcmp(path, "..")) {
203 		path[0] = '\0';
204 		return;
205 	}
206 
207 	/* remove every ../ in the path */
208 	while (1) {
209 		if ((s = strstr(path, "../")) == NULL)
210 			return;
211 		memmove(s, s+3, strlen(s)+1);	/* copy also the \0 */
212 	}
213 }
214 
215 int
216 path_isdir(char *path)
217 {
218 	if (*path == '\0')
219 		return 1;
220 	return path[strlen(path)-1] == '/';
221 }
222 
223 int
224 start_reply(struct pollfd *pfd, struct client *client, int code, const char *reason)
225 {
226 	char buf[1030] = {0}; 	/* status + ' ' + max reply len + \r\n\0 */
227 	int len;
228 	int ret;
229 
230 	client->code = code;
231 	client->meta = reason;
232 	client->state = S_INITIALIZING;
233 
234 	len = snprintf(buf, sizeof(buf), "%d %s\r\n", code, reason);
235 	assert(len < (int)sizeof(buf));
236 	ret = tls_write(client->ctx, buf, len);
237 	if (ret == TLS_WANT_POLLIN) {
238 		pfd->events = POLLIN;
239 		return 0;
240 	}
241 
242 	if (ret == TLS_WANT_POLLOUT) {
243 		pfd->events = POLLOUT;
244 		return 0;
245 	}
246 
247 	return 1;
248 }
249 
250 int
251 isdir(int fd)
252 {
253 	struct stat sb;
254 
255 	if (fstat(fd, &sb) == -1) {
256 		warn("fstat");
257 		return 1; 	/* we'll probably fail later on anyway */
258 	}
259 
260 	return S_ISDIR(sb.st_mode);
261 }
262 
263 ssize_t
264 filesize(int fd)
265 {
266 	ssize_t len;
267 
268 	if ((len = lseek(fd, 0, SEEK_END)) == -1)
269 		return -1;
270 	if (lseek(fd, 0, SEEK_SET) == -1)
271 		return -1;
272 	return len;
273 }
274 
275 const char *
276 path_ext(const char *path)
277 {
278 	const char *end;
279 
280 	end = path + strlen(path)-1; /* the last byte before the NUL */
281 	for (; end != path; --end) {
282 		if (*end == '.')
283 			return end+1;
284 		if (*end == '/')
285 			break;
286 	}
287 
288 	return NULL;
289 }
290 
291 const char *
292 mime(const char *path)
293 {
294 	const char *ext, *def = "application/octet-stream";
295 	struct etm *t;
296 
297 	if ((ext = path_ext(path)) == NULL)
298 		return def;
299 
300 	for (t = filetypes; t->mime != NULL; ++t)
301 		if (!strcmp(ext, t->ext))
302 			return t->mime;
303 
304 	return def;
305 }
306 
307 int
308 open_file(char *path, struct pollfd *fds, struct client *c)
309 {
310 	char fpath[PATHBUF];
311 
312 	assert(path != NULL);
313 
314 	bzero(fpath, sizeof(fpath));
315 
316 	if (*path != '.')
317 		fpath[0] = '.';
318 	strlcat(fpath, path, PATHBUF);
319 
320 	if ((c->fd = openat(dirfd, fpath, O_RDONLY | O_NOFOLLOW)) == -1) {
321 		LOG(c, "open failed: %s", fpath);
322 		if (!start_reply(fds, c, NOT_FOUND, "not found"))
323 			return 0;
324 		goodbye(fds, c);
325 		return 0;
326 	}
327 
328 	if (isdir(c->fd)) {
329 		LOG(c, "%s is a directory, trying %s/index.gmi", fpath, fpath);
330 		close(c->fd);
331 		c->fd = -1;
332 		send_dir(fpath, fds, c);
333 		return 0;
334 	}
335 
336 	if ((c->len = filesize(c->fd)) == -1) {
337 		LOG(c, "failed to get file size for %s", fpath);
338 		goodbye(fds, c);
339 		return 0;
340 	}
341 
342 	if ((c->buf = mmap(NULL, c->len, PROT_READ, MAP_PRIVATE,
343 		    c->fd, 0)) == MAP_FAILED) {
344 		warn("mmap: %s", fpath);
345 		goodbye(fds, c);
346 		return 0;
347 	}
348 	c->i = c->buf;
349 
350 	return start_reply(fds, c, SUCCESS, mime(fpath));
351 }
352 
353 void
354 send_file(char *path, struct pollfd *fds, struct client *c)
355 {
356 	ssize_t ret, len;
357 
358 	if (c->fd == -1) {
359 		if (!open_file(path, fds, c))
360 			return;
361 		c->state = S_SENDING;
362 	}
363 
364 	len = (c->buf + c->len) - c->i;
365 
366 	while (len > 0) {
367 		switch (ret = tls_write(c->ctx, c->i, len)) {
368 		case -1:
369 			LOG(c, "tls_write: %s", tls_error(c->ctx));
370 			goodbye(fds, c);
371 			return;
372 
373 		case TLS_WANT_POLLIN:
374 			fds->events = POLLIN;
375 			return;
376 
377 		case TLS_WANT_POLLOUT:
378 			fds->events = POLLOUT;
379 			return;
380 
381 		default:
382 			c->i += ret;
383 			len -= ret;
384 			break;
385 		}
386 	}
387 
388 	goodbye(fds, c);
389 }
390 
391 void
392 send_dir(char *path, struct pollfd *fds, struct client *client)
393 {
394 	char fpath[PATHBUF];
395 	size_t len;
396 
397 	bzero(fpath, PATHBUF);
398 
399 	if (path[0] != '.')
400 		fpath[0] = '.';
401 
402 	/* this cannot fail since sizeof(fpath) > maxlen of path */
403 	strlcat(fpath, path, PATHBUF);
404 	len = strlen(fpath);
405 
406 	/* add a trailing / in case. */
407 	if (fpath[len-1] != '/') {
408 		fpath[len] = '/';
409 	}
410 
411 	strlcat(fpath, "index.gmi", sizeof(fpath));
412 
413 	send_file(fpath, fds, client);
414 }
415 
416 void
417 handle(struct pollfd *fds, struct client *client)
418 {
419 	char buf[GEMINI_URL_LEN];
420 	char *path;
421 
422 	switch (client->state) {
423 	case S_OPEN:
424 		bzero(buf, GEMINI_URL_LEN);
425 		switch (tls_read(client->ctx, buf, sizeof(buf)-1)) {
426 		case -1:
427 			LOG(client, "tls_read: %s", tls_error(client->ctx));
428 			goodbye(fds, client);
429 			return;
430 
431 		case TLS_WANT_POLLIN:
432 			fds->events = POLLIN;
433 			return;
434 
435 		case TLS_WANT_POLLOUT:
436 			fds->events = POLLOUT;
437 			return;
438 		}
439 
440 		if (!url_trim(client, buf)) {
441 			if (!start_reply(fds, client, BAD_REQUEST, "bad request"))
442 				return;
443 			goodbye(fds, client);
444 			return;
445 		}
446 
447 		if ((path = url_start_of_request(buf)) == NULL) {
448 			if (!start_reply(fds, client, BAD_REQUEST, "bad request"))
449 				return;
450 			goodbye(fds, client);
451 			return;
452 		}
453 
454 		adjust_path(path);
455 		LOG(client, "get %s", path);
456 
457 		if (path_isdir(path))
458 			send_dir(path, fds, client);
459 		else
460 			send_file(path, fds, client);
461 		break;
462 
463 	case S_INITIALIZING:
464 		if (!start_reply(fds, client, client->code, client->meta))
465 			return;
466 
467 		if (client->code != SUCCESS) {
468 			/* we don't need a body */
469 			goodbye(fds, client);
470 			return;
471 		}
472 
473 		client->state = S_SENDING;
474 
475 		/* fallthrough */
476 
477 	case S_SENDING:
478 		send_file(NULL, fds, client);
479 		break;
480 
481 	case S_CLOSING:
482 		goodbye(fds, client);
483 		break;
484 
485 	default:
486 		/* unreachable */
487 		abort();
488 	}
489 }
490 
491 void
492 mark_nonblock(int fd)
493 {
494 	int flags;
495 
496 	if ((flags = fcntl(fd, F_GETFL)) == -1)
497 		err(1, "fcntl(F_GETFL)");
498 	if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1)
499 		err(1, "fcntl(F_SETFL)");
500 }
501 
502 int
503 make_socket(int port, int family)
504 {
505 	int sock, v;
506 	struct sockaddr_in addr4;
507 	struct sockaddr_in6 addr6;
508 	struct sockaddr *addr;
509 	socklen_t len;
510 
511         switch (family) {
512 	case AF_INET:
513 		bzero(&addr4, sizeof(addr4));
514 		addr4.sin_family = family;
515 		addr4.sin_port = htons(port);
516 		addr4.sin_addr.s_addr = INADDR_ANY;
517 		addr = (struct sockaddr*)&addr4;
518 		len = sizeof(addr4);
519 		break;
520 
521 	case AF_INET6:
522 		bzero(&addr6, sizeof(addr6));
523 		addr6.sin6_family = AF_INET6;
524 		addr6.sin6_port = htons(port);
525 		addr6.sin6_addr = in6addr_any;
526 		addr = (struct sockaddr*)&addr6;
527 		len = sizeof(addr6);
528 		break;
529 
530 	default:
531 		/* unreachable */
532 		abort();
533 	}
534 
535 	if ((sock = socket(family, SOCK_STREAM, 0)) == -1)
536 		err(1, "socket");
537 
538 	v = 1;
539 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &v, sizeof(v)) == -1)
540 		err(1, "setsockopt(SO_REUSEADDR)");
541 
542 	v = 1;
543 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &v, sizeof(v)) == -1)
544 		err(1, "setsockopt(SO_REUSEPORT)");
545 
546 	mark_nonblock(sock);
547 
548 	if (bind(sock, addr, len) == -1)
549 		err(1, "bind");
550 
551 	if (listen(sock, 16) == -1)
552 		err(1, "listen");
553 
554 	return sock;
555 }
556 
557 void
558 do_accept(int sock, struct tls *ctx, struct pollfd *fds, struct client *clients)
559 {
560 	int i, fd;
561 	struct sockaddr_in addr;
562 	socklen_t len;
563 
564 	len = sizeof(addr);
565 	if ((fd = accept(sock, (struct sockaddr*)&addr, &len)) == -1) {
566 		if (errno == EWOULDBLOCK)
567 			return;
568 		err(1, "accept");
569 	}
570 
571 	mark_nonblock(fd);
572 
573 	for (i = 0; i < MAX_USERS; ++i) {
574 		if (fds[i].fd == -1) {
575 			bzero(&clients[i], sizeof(struct client));
576 			if (tls_accept_socket(ctx, &clients[i].ctx, fd) == -1)
577 				break; /* goodbye fd! */
578 
579 			fds[i].fd = fd;
580 			fds[i].events = POLLIN;
581 
582 			clients[i].state = S_OPEN;
583 			clients[i].fd = -1;
584 			clients[i].buf = MAP_FAILED;
585 			clients[i].af = AF_INET;
586 			clients[i].addr = addr.sin_addr;
587 
588 			return;
589 		}
590 	}
591 
592 	close(fd);
593 }
594 
595 void
596 goodbye(struct pollfd *pfd, struct client *c)
597 {
598 	ssize_t ret;
599 
600 	c->state = S_CLOSING;
601 
602 	ret = tls_close(c->ctx);
603 	if (ret == TLS_WANT_POLLIN) {
604 		pfd->events = POLLIN;
605 		return;
606 	}
607 	if (ret == TLS_WANT_POLLOUT) {
608 		pfd->events = POLLOUT;
609 		return;
610 	}
611 
612 	tls_free(c->ctx);
613 	c->ctx = NULL;
614 
615 	if (c->buf != MAP_FAILED)
616 		munmap(c->buf, c->len);
617 
618 	if (c->fd != -1)
619 		close(c->fd);
620 
621 	close(pfd->fd);
622 	pfd->fd = -1;
623 }
624 
625 void
626 loop(struct tls *ctx, int sock)
627 {
628 	int i, todo;
629 	struct client clients[MAX_USERS];
630 	struct pollfd fds[MAX_USERS];
631 
632 	for (i = 0; i < MAX_USERS; ++i) {
633 		fds[i].fd = -1;
634 		fds[i].events = POLLIN;
635 		bzero(&clients[i], sizeof(struct client));
636 	}
637 
638 	fds[0].fd = sock;
639 
640 	for (;;) {
641 		if ((todo = poll(fds, MAX_USERS, INFTIM)) == -1)
642 			err(1, "poll");
643 
644 		for (i = 0; i < MAX_USERS; i++) {
645 			assert(i < MAX_USERS);
646 
647 			if (fds[i].revents == 0)
648 				continue;
649 
650 			if (fds[i].revents & (POLLERR|POLLNVAL))
651 				err(1, "bad fd %d", fds[i].fd);
652 
653 			if (fds[i].revents & POLLHUP) {
654 				goodbye(&fds[i], &clients[i]);
655 				continue;
656 			}
657 
658 			todo--;
659 
660 			if (i == 0) { /* new client */
661 				do_accept(sock, ctx, fds, clients);
662 				continue;
663 			}
664 
665 			handle(&fds[i], &clients[i]);
666 		}
667 	}
668 }
669 
670 void
671 usage(const char *me)
672 {
673 	fprintf(stderr,
674 	    "USAGE: %s [-h] [-c cert.pem] [-d docs] [-k key.pem]\n",
675 	    me);
676 }
677 
678 int
679 main(int argc, char **argv)
680 {
681 	const char *cert = "cert.pem", *key = "key.pem", *dir = "docs";
682 	struct tls *ctx = NULL;
683 	struct tls_config *conf;
684 	int sock, ch;
685 
686 	signal(SIGPIPE, SIG_IGN);
687 
688 	logfd = 2;		/* stderr */
689 
690 	while ((ch = getopt(argc, argv, "c:d:hk:l:")) != -1) {
691 		switch (ch) {
692 		case 'c':
693 			cert = optarg;
694 			break;
695 
696 		case 'd':
697 			dir = optarg;
698 			break;
699 
700 		case 'h':
701 			usage(*argv);
702 			return 0;
703 
704 		case 'k':
705 			key = optarg;
706 			break;
707 
708 		case 'l':
709 			/* open log file or create it with 644 */
710 			if ((logfd = open(optarg, O_WRONLY | O_CREAT,
711 					S_IRUSR | S_IWUSR | S_IRGRP | S_IWOTH)) == -1)
712 				err(1, "%s", optarg);
713 			break;
714 
715 		default:
716 			usage(*argv);
717 			return 1;
718 		}
719 	}
720 
721 	if ((conf = tls_config_new()) == NULL)
722 		err(1, "tls_config_new");
723 
724 	if (tls_config_set_protocols(conf,
725 	    TLS_PROTOCOL_TLSv1_2 | TLS_PROTOCOL_TLSv1_3) == -1)
726 		err(1, "tls_config_set_protocols");
727 
728 	if (tls_config_set_cert_file(conf, cert) == -1)
729 		err(1, "tls_config_set_cert_file: %s", cert);
730 
731 	if (tls_config_set_key_file(conf, key) == -1)
732 		err(1, "tls_config_set_key_file: %s", key);
733 
734 	if ((ctx = tls_server()) == NULL)
735 		err(1, "tls_server");
736 
737 	if (tls_configure(ctx, conf) == -1)
738 		errx(1, "tls_configure: %s", tls_error(ctx));
739 
740 	sock = make_socket(1965, AF_INET);
741 
742 	if ((dirfd = open(dir, O_RDONLY | O_DIRECTORY)) == -1)
743 		err(1, "open: %s", dir);
744 
745 	if (unveil(dir, "r") == -1)
746 		err(1, "unveil");
747 
748 	if (pledge("stdio rpath inet", "") == -1)
749 		err(1, "pledge");
750 
751 	loop(ctx, sock);
752 
753 	close(sock);
754 	tls_free(ctx);
755 	tls_config_free(conf);
756 }