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Date:: Mon Feb 8 10:01:45 2021 UTC
Message:: rewrite main loop using libevent
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1 /*
2  * Copyright (c) 2021 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 <netdb.h>
21 
22 #include <assert.h>
23 #include <errno.h>
24 #include <event.h>
25 #include <fcntl.h>
26 #include <fnmatch.h>
27 #include <limits.h>
28 #include <string.h>
29 
30 #include "gmid.h"
31 
32 struct server {
33 	struct client	 clients[MAX_USERS];
34 	struct tls	*ctx;
35 };
36 
37 struct server_events {
38 	struct event	e4;
39 	int		has_ipv6;
40 	struct event	e6;
41 	struct event	sighup;
42 };
43 
44 int connected_clients;
45 
46 static inline void reschedule_read(int, struct client*, statefn);
47 static inline void reschedule_write(int, struct client*, statefn);
48 
49 static int	 check_path(struct client*, const char*, int*);
50 static void	 open_file(struct client*);
51 static void	 load_file(struct client*);
52 static void	 check_for_cgi(struct client*);
53 static void	 handle_handshake(int, short, void*);
54 static int	 apply_block_return(struct client*);
55 static void	 handle_open_conn(int, short, void*);
56 static void	 start_reply(struct client*, int, const char*);
57 static void	 handle_start_reply(int, short, void*);
58 static void	 start_cgi(const char*, const char*, struct client*);
59 static void	 send_file(int, short, void*);
60 static void	 open_dir(struct client*);
61 static void	 redirect_canonical_dir(struct client*);
62 static void	 enter_handle_dirlist(int, short, void*);
63 static void	 handle_dirlist(int, short, void*);
64 static int 	 read_next_dir_entry(struct client*);
65 static void	 send_directory_listing(int, short, void*);
66 static void	 handle_cgi_reply(int, short, void*);
67 static void	 handle_cgi(int, short, void*);
68 static void	 close_conn(int, short, void*);
69 static void	 do_accept(int, short, void*);
70 static void	 handle_sighup(int, short, void*);
71 
72 static inline void
73 reschedule_read(int fd, struct client *c, statefn fn)
74 {
75 	event_once(fd, EV_READ, fn, c, NULL);
76 }
77 
78 void
79 reschedule_write(int fd, struct client *c, statefn fn)
80 {
81 	event_once(fd, EV_WRITE, fn, c, NULL);
82 }
83 
84 const char *
85 vhost_lang(struct vhost *v, const char *path)
86 {
87 	struct location *loc;
88 
89 	if (v == NULL || path == NULL)
90 		return NULL;
91 
92 	for (loc = &v->locations[1]; loc->match != NULL; ++loc) {
93 		if (loc->lang != NULL) {
94 			if (!fnmatch(loc->match, path, 0))
95 				return loc->lang;
96 		}
97 	}
98 
99 	return v->locations[0].lang;
100 }
101 
102 const char *
103 vhost_default_mime(struct vhost *v, const char *path)
104 {
105 	struct location *loc;
106 	const char *default_mime = "application/octet-stream";
107 
108 	if (v == NULL || path == NULL)
109 		return default_mime;
110 
111 	for (loc = &v->locations[1]; loc->match != NULL; ++loc) {
112 		if (loc->default_mime != NULL) {
113 			if (!fnmatch(loc->match, path, 0))
114 				return loc->default_mime;
115 		}
116 	}
117 
118 	if (v->locations[0].default_mime != NULL)
119 		return v->locations[0].default_mime;
120 	return default_mime;
121 }
122 
123 const char *
124 vhost_index(struct vhost *v, const char *path)
125 {
126 	struct location *loc;
127 	const char *index = "index.gmi";
128 
129 	if (v == NULL || path == NULL)
130 		return index;
131 
132 	for (loc = &v->locations[1]; loc->match != NULL; ++loc) {
133 		if (loc->index != NULL) {
134 			if (!fnmatch(loc->match, path, 0))
135 				return loc->index;
136 		}
137 	}
138 
139 	if (v->locations[0].index != NULL)
140 		return v->locations[0].index;
141 	return index;
142 }
143 
144 int
145 vhost_auto_index(struct vhost *v, const char *path)
146 {
147 	struct location *loc;
148 
149 	if (v == NULL || path == NULL)
150 		return 0;
151 
152 	for (loc = &v->locations[1]; loc->match != NULL; ++loc) {
153 		if (loc->auto_index != 0) {
154 			if (!fnmatch(loc->match, path, 0))
155 				return loc->auto_index == 1;
156 		}
157 	}
158 
159 	return v->locations[0].auto_index == 1;
160 }
161 
162 int
163 vhost_block_return(struct vhost *v, const char *path, int *code, const char **fmt)
164 {
165 	struct location *loc;
166 
167 	if (v == NULL || path == NULL)
168 		return 0;
169 
170 	for (loc = &v->locations[1]; loc->match != NULL; ++loc) {
171 		if (loc->block_code != 0) {
172 			if (!fnmatch(loc->match, path, 0)) {
173 				*code = loc->block_code;
174 				*fmt = loc->block_fmt;
175 				return 1;
176 			}
177 		}
178 	}
179 
180 	*code = v->locations[0].block_code;
181 	*fmt = v->locations[0].block_fmt;
182 	return v->locations[0].block_code != 0;
183 }
184 
185 int
186 vhost_strip(struct vhost *v, const char *path)
187 {
188 	struct location *loc;
189 
190 	if (v == NULL || path == NULL)
191 		return 0;
192 
193 	for (loc = &v->locations[1]; loc->match != NULL; ++loc) {
194 		if (loc->strip != 0) {
195 			if (!fnmatch(loc->match, path, 0))
196 				return loc->strip;
197 		}
198 	}
199 
200 	return v->locations[0].strip;
201 }
202 
203 static int
204 check_path(struct client *c, const char *path, int *fd)
205 {
206 	struct stat sb;
207 	const char *p;
208 	int flags;
209 
210 	assert(path != NULL);
211 
212 	if (*path == '\0')
213 		p = ".";
214 	else if (*path == '/')
215 		/* in send_dir we add an initial / (to be
216 		 * redirect-friendly), but here we want to skip it */
217 		p = path+1;
218 	else
219 		p = path;
220 
221 	flags = O_RDONLY | O_NOFOLLOW;
222 
223 	if (*fd == -1 && (*fd = openat(c->host->dirfd, p, flags)) == -1)
224 		return FILE_MISSING;
225 
226 	if (fstat(*fd, &sb) == -1) {
227 		log_notice(c, "failed stat for %s: %s", path, strerror(errno));
228 		return FILE_MISSING;
229 	}
230 
231 	if (S_ISDIR(sb.st_mode))
232 		return FILE_DIRECTORY;
233 
234 	if (sb.st_mode & S_IXUSR)
235 		return FILE_EXECUTABLE;
236 
237 	return FILE_EXISTS;
238 }
239 
240 static void
241 open_file(struct client *c)
242 {
243 	switch (check_path(c, c->iri.path, &c->pfd)) {
244 	case FILE_EXECUTABLE:
245 		if (c->host->cgi != NULL && !fnmatch(c->host->cgi, c->iri.path, 0)) {
246 			start_cgi(c->iri.path, "", c);
247 			return;
248 		}
249 
250 		/* fallthrough */
251 
252 	case FILE_EXISTS:
253 		load_file(c);
254 		return;
255 
256 	case FILE_DIRECTORY:
257 		open_dir(c);
258 		return;
259 
260 	case FILE_MISSING:
261 		if (c->host->cgi != NULL && !fnmatch(c->host->cgi, c->iri.path, 0)) {
262 			check_for_cgi(c);
263 			return;
264 		}
265 		start_reply(c, NOT_FOUND, "not found");
266 		return;
267 
268 	default:
269 		/* unreachable */
270 		abort();
271 	}
272 }
273 
274 static void
275 load_file(struct client *c)
276 {
277 	if ((c->len = filesize(c->pfd)) == -1) {
278 		log_err(c, "failed to get file size for %s: %s",
279 		    c->iri.path, strerror(errno));
280 		start_reply(c, TEMP_FAILURE, "internal server error");
281 		return;
282 	}
283 
284 	if ((c->buf = mmap(NULL, c->len, PROT_READ, MAP_PRIVATE,
285 		    c->pfd, 0)) == MAP_FAILED) {
286 		log_err(c, "mmap: %s: %s", c->iri.path, strerror(errno));
287 		start_reply(c, TEMP_FAILURE, "internal server error");
288 		return;
289 	}
290 	c->i = c->buf;
291 	c->next = send_file;
292 	start_reply(c, SUCCESS, mime(c->host, c->iri.path));
293 }
294 
295 /*
296  * the inverse of this algorithm, i.e. starting from the start of the
297  * path + strlen(cgi), and checking if each component, should be
298  * faster.  But it's tedious to write.  This does the opposite: starts
299  * from the end and strip one component at a time, until either an
300  * executable is found or we emptied the path.
301  */
302 static void
303 check_for_cgi(struct client *c)
304 {
305 	char path[PATH_MAX];
306 	char *end;
307 
308 	strlcpy(path, c->iri.path, sizeof(path));
309 	end = strchr(path, '\0');
310 
311 	while (end > path) {
312 		/* go up one level.  UNIX paths are simple and POSIX
313 		 * dirname, with its ambiguities on if the given path
314 		 * is changed or not, gives me headaches. */
315 		while (*end != '/')
316 			end--;
317 		*end = '\0';
318 
319 		switch (check_path(c, path, &c->pfd)) {
320 		case FILE_EXECUTABLE:
321 			start_cgi(path, end+1, c);
322 			return;
323 		case FILE_MISSING:
324 			break;
325 		default:
326 			goto err;
327 		}
328 
329 		*end = '/';
330 		end--;
331 	}
332 
333 err:
334 	start_reply(c, NOT_FOUND, "not found");
335 	return;
336 }
337 
338 void
339 mark_nonblock(int fd)
340 {
341 	int flags;
342 
343 	if ((flags = fcntl(fd, F_GETFL)) == -1)
344 		fatal("fcntl(F_GETFL): %s", strerror(errno));
345 	if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1)
346 		fatal("fcntl(F_SETFL): %s", strerror(errno));
347 }
348 
349 static void
350 handle_handshake(int fd, short ev, void *d)
351 {
352 	struct client *c = d;
353 	struct vhost *h;
354 	const char *servname;
355 	const char *parse_err = "unknown error";
356 
357 	switch (tls_handshake(c->ctx)) {
358 	case 0:  /* success */
359 	case -1: /* already handshaked */
360 		break;
361 	case TLS_WANT_POLLIN:
362 		reschedule_read(fd, c, &handle_handshake);
363 		return;
364 	case TLS_WANT_POLLOUT:
365 		reschedule_write(fd, c, &handle_handshake);
366 		return;
367 	default:
368 		/* unreachable */
369 		abort();
370 	}
371 
372 	servname = tls_conn_servername(c->ctx);
373 	if (!puny_decode(servname, c->domain, sizeof(c->domain), &parse_err)) {
374 		log_info(c, "puny_decode: %s", parse_err);
375 		goto err;
376 	}
377 
378 	for (h = hosts; h->domain != NULL; ++h) {
379 		if (!fnmatch(h->domain, c->domain, 0))
380 			break;
381 	}
382 
383 	log_debug(c, "handshake: SNI: \"%s\"; decoded: \"%s\"; matched: \"%s\"",
384 	    servname != NULL ? servname : "(null)",
385 	    c->domain,
386 	    h->domain != NULL ? h->domain : "(null)");
387 
388 	if (h->domain != NULL) {
389 		c->host = h;
390 		handle_open_conn(fd, ev, c);
391 		return;
392 	}
393 
394 err:
395 	if (servname != NULL)
396 		strncpy(c->req, servname, sizeof(c->req));
397 	else
398 		strncpy(c->req, "null", sizeof(c->req));
399 
400 	start_reply(c, BAD_REQUEST, "Wrong/malformed host or missing SNI");
401 }
402 
403 /* 1 if a matching `block return' (and apply it), 0 otherwise */
404 static int
405 apply_block_return(struct client *c)
406 {
407 	char *t, *path, buf[32];
408 	const char *fmt;
409 	int strip, code;
410 	size_t i;
411 
412 	if (!vhost_block_return(c->host, c->iri.path, &code, &fmt))
413 		return 0;
414 
415 	strip = vhost_strip(c->host, c->iri.path);
416 	path = c->iri.path;
417 	while (strip > 0) {
418 		if ((t = strchr(path, '/')) == NULL) {
419 			path = strchr(path, '\0');
420 			break;
421 		}
422 		path = t;
423 		strip--;
424 	}
425 
426 	memset(buf, 0, sizeof(buf));
427 	for (i = 0; *fmt; ++fmt) {
428 		if (i == sizeof(buf)-1 || *fmt == '%') {
429 			strlcat(c->sbuf, buf, sizeof(c->sbuf));
430 			memset(buf, 0, sizeof(buf));
431 			i = 0;
432 		}
433 
434 		if (*fmt != '%') {
435 			buf[i++] = *fmt;
436 			continue;
437 		}
438 
439 		switch (*++fmt) {
440 		case '%':
441 			strlcat(c->sbuf, "%", sizeof(c->sbuf));
442 			break;
443 		case 'p':
444 			strlcat(c->sbuf, path, sizeof(c->sbuf));
445 			break;
446 		case 'q':
447 			strlcat(c->sbuf, c->iri.query, sizeof(c->sbuf));
448 			break;
449 		case 'P':
450 			snprintf(buf, sizeof(buf), "%d", conf.port);
451 			strlcat(c->sbuf, buf, sizeof(c->sbuf));
452 			memset(buf, 0, sizeof(buf));
453 			break;
454 		case 'N':
455 			strlcat(c->sbuf, c->domain, sizeof(c->sbuf));
456 			break;
457 		default:
458 			fatal("%s: unknown fmt specifier %c",
459 			    __func__, *fmt);
460 		}
461 	}
462 
463 	if (i != 0)
464 		strlcat(c->sbuf, buf, sizeof(c->sbuf));
465 
466 	start_reply(c, code, c->sbuf);
467 	return 1;
468 }
469 
470 static void
471 handle_open_conn(int fd, short ev, void *d)
472 {
473 	struct client *c = d;
474 	const char *parse_err = "invalid request";
475 	char decoded[DOMAIN_NAME_LEN];
476 
477 	bzero(c->req, sizeof(c->req));
478 	bzero(&c->iri, sizeof(c->iri));
479 
480 	switch (tls_read(c->ctx, c->req, sizeof(c->req)-1)) {
481 	case -1:
482 		log_err(c, "tls_read: %s", tls_error(c->ctx));
483 		close_conn(fd, ev, c);
484 		return;
485 
486 	case TLS_WANT_POLLIN:
487 		reschedule_read(fd, c, &handle_open_conn);
488 		return;
489 
490 	case TLS_WANT_POLLOUT:
491 		reschedule_write(fd, c, &handle_open_conn);
492 		return;
493 	}
494 
495 	if (!trim_req_iri(c->req, &parse_err)
496 	    || !parse_iri(c->req, &c->iri, &parse_err)
497 	    || !puny_decode(c->iri.host, decoded, sizeof(decoded), &parse_err)) {
498 		log_info(c, "iri parse error: %s", parse_err);
499 		start_reply(c, BAD_REQUEST, "invalid request");
500 		return;
501 	}
502 
503 	if (c->iri.port_no != conf.port
504 	    || strcmp(c->iri.schema, "gemini")
505 	    || strcmp(decoded, c->domain)) {
506 		start_reply(c, PROXY_REFUSED, "won't proxy request");
507 		return;
508 	}
509 
510 	if (apply_block_return(c))
511 		return;
512 
513 	if (c->host->entrypoint != NULL) {
514 		start_cgi(c->host->entrypoint, c->iri.path, c);
515 		return;
516 	}
517 
518 	open_file(c);
519 }
520 
521 static void
522 start_reply(struct client *c, int code, const char *meta)
523 {
524 	c->code = code;
525 	c->meta = meta;
526 	handle_start_reply(c->fd, 0, c);
527 }
528 
529 static void
530 handle_start_reply(int fd, short ev, void *d)
531 {
532 	struct client *c = d;
533 	char buf[1030];		/* status + ' ' + max reply len + \r\n\0 */
534 	const char *lang;
535 	size_t len;
536 
537 	lang = vhost_lang(c->host, c->iri.path);
538 
539 	snprintf(buf, sizeof(buf), "%d ", c->code);
540 	strlcat(buf, c->meta, sizeof(buf));
541 	if (!strcmp(c->meta, "text/gemini") && lang != NULL) {
542 		strlcat(buf, "; lang=", sizeof(buf));
543 		strlcat(buf, lang, sizeof(buf));
544 	}
545 
546 	len = strlcat(buf, "\r\n", sizeof(buf));
547 	assert(len < sizeof(buf));
548 
549 	switch (tls_write(c->ctx, buf, len)) {
550 	case -1:
551 		close_conn(fd, ev, c);
552 		return;
553 	case TLS_WANT_POLLIN:
554 		reschedule_read(fd, c, &handle_start_reply);
555 		return;
556 	case TLS_WANT_POLLOUT:
557 		reschedule_write(fd, c, &handle_start_reply);
558 		return;
559 	}
560 
561 	log_request(c, buf, sizeof(buf));
562 
563 	if (c->code != SUCCESS)
564 		close_conn(fd, ev, c);
565 	else
566 		c->next(fd, ev, c);
567 }
568 
569 static void
570 start_cgi(const char *spath, const char *relpath, struct client *c)
571 {
572 	char addr[NI_MAXHOST];
573 	int e;
574 
575 	e = getnameinfo((struct sockaddr*)&c->addr, sizeof(c->addr),
576 	    addr, sizeof(addr),
577 	    NULL, 0,
578 	    NI_NUMERICHOST);
579 	if (e != 0)
580 		goto err;
581 
582 	if (!send_iri(exfd, &c->iri)
583 	    || !send_string(exfd, spath)
584 	    || !send_string(exfd, relpath)
585 	    || !send_string(exfd, addr)
586 	    || !send_string(exfd, tls_peer_cert_subject(c->ctx))
587 	    || !send_string(exfd, tls_peer_cert_issuer(c->ctx))
588 	    || !send_string(exfd, tls_peer_cert_hash(c->ctx))
589 	    || !send_time(exfd, tls_peer_cert_notbefore(c->ctx))
590 	    || !send_time(exfd, tls_peer_cert_notafter(c->ctx))
591 	    || !send_vhost(exfd, c->host))
592 		goto err;
593 
594 	close(c->pfd);
595 	if ((c->pfd = recv_fd(exfd)) == -1) {
596 		start_reply(c, TEMP_FAILURE, "internal server error");
597 		return;
598 	}
599 
600 	reschedule_read(c->pfd, c, &handle_cgi_reply);
601 	return;
602 
603 err:
604 	/* fatal("cannot talk to the executor process: %s", strerror(errno)); */
605 	fatal("cannot talk to the executor process");
606 }
607 
608 static void
609 send_file(int fd, short ev, void *d)
610 {
611 	struct client *c = d;
612 	ssize_t ret, len;
613 
614 	len = (c->buf + c->len) - c->i;
615 
616 	while (len > 0) {
617 		switch (ret = tls_write(c->ctx, c->i, len)) {
618 		case -1:
619 			log_err(c, "tls_write: %s", tls_error(c->ctx));
620 			close_conn(fd, ev, c);
621 			return;
622 
623 		case TLS_WANT_POLLIN:
624 			reschedule_read(fd, c, &send_file);
625 			return;
626 
627 		case TLS_WANT_POLLOUT:
628 			reschedule_write(fd, c, &send_file);
629 			return;
630 
631 		default:
632 			c->i += ret;
633 			len -= ret;
634 			break;
635 		}
636 	}
637 
638 	close_conn(fd, ev, c);
639 }
640 
641 static void
642 open_dir(struct client *c)
643 {
644 	size_t len;
645 	int dirfd;
646 	char *before_file;
647 
648 	len = strlen(c->iri.path);
649 	if (len > 0 && !ends_with(c->iri.path, "/")) {
650 		redirect_canonical_dir(c);
651 		return;
652 	}
653 
654 	strlcpy(c->sbuf, "/", sizeof(c->sbuf));
655 	strlcat(c->sbuf, c->iri.path, sizeof(c->sbuf));
656 	if (!ends_with(c->sbuf, "/"))
657 		strlcat(c->sbuf, "/", sizeof(c->sbuf));
658 	before_file = strchr(c->sbuf, '\0');
659 	len = strlcat(c->sbuf, vhost_index(c->host, c->iri.path),
660 	    sizeof(c->sbuf));
661 	if (len >= sizeof(c->sbuf)) {
662 		start_reply(c, TEMP_FAILURE, "internal server error");
663 		return;
664 	}
665 
666 	c->iri.path = c->sbuf;
667 
668 	/* close later unless we have to generate the dir listing */
669 	dirfd = c->pfd;
670 	c->pfd = -1;
671 
672 	switch (check_path(c, c->iri.path, &c->pfd)) {
673 	case FILE_EXECUTABLE:
674 		if (c->host->cgi != NULL && !fnmatch(c->host->cgi, c->iri.path, 0)) {
675 			start_cgi(c->iri.path, "", c);
676 			break;
677 		}
678 
679 		/* fallthrough */
680 
681 	case FILE_EXISTS:
682                 load_file(c);
683 		break;
684 
685 	case FILE_DIRECTORY:
686 		start_reply(c, TEMP_REDIRECT, c->sbuf);
687 		break;
688 
689 	case FILE_MISSING:
690 		*before_file = '\0';
691 
692 		if (!vhost_auto_index(c->host, c->iri.path)) {
693 			start_reply(c, NOT_FOUND, "not found");
694 			break;
695 		}
696 
697 		c->pfd = dirfd;
698 		c->next = enter_handle_dirlist;
699 
700 		if ((c->dir = fdopendir(c->pfd)) == NULL) {
701 			log_err(c, "fdopendir(%d) (vhost:%s) %s: %s",
702 			    c->pfd, c->host->domain, c->iri.path, strerror(errno));
703 			start_reply(c, TEMP_FAILURE, "internal server error");
704 			return;
705 		}
706 		c->off = 0;
707 
708                 start_reply(c, SUCCESS, "text/gemini");
709 		return;
710 
711 	default:
712 		/* unreachable */
713 		abort();
714 	}
715 
716 	close(dirfd);
717 }
718 
719 static void
720 redirect_canonical_dir(struct client *c)
721 {
722 	size_t len;
723 
724 	strlcpy(c->sbuf, "/", sizeof(c->sbuf));
725 	strlcat(c->sbuf, c->iri.path, sizeof(c->sbuf));
726 	len = strlcat(c->sbuf, "/", sizeof(c->sbuf));
727 
728 	if (len >= sizeof(c->sbuf)) {
729 		start_reply(c, TEMP_FAILURE, "internal server error");
730 		return;
731 	}
732 
733 	start_reply(c, TEMP_REDIRECT, c->sbuf);
734 }
735 
736 static void
737 enter_handle_dirlist(int fd, short ev, void *d)
738 {
739 	struct client *c = d;
740 	char b[PATH_MAX];
741 	size_t l;
742 
743 	strlcpy(b, c->iri.path, sizeof(b));
744 	l = snprintf(c->sbuf, sizeof(c->sbuf),
745 	    "# Index of %s\n\n", b);
746 	if (l >= sizeof(c->sbuf)) {
747 		/* this is impossible, given that we have enough space
748 		 * in c->sbuf to hold the ancilliary string plus the
749 		 * full path; but it wouldn't read nice without some
750 		 * error checking, and I'd like to avoid a strlen. */
751 		close_conn(fd, ev, c);
752 		return;
753 	}
754 
755 	c->len = l;
756 	handle_dirlist(fd, ev, c);
757 }
758 
759 static void
760 handle_dirlist(int fd, short ev, void *d)
761 {
762 	struct client *c = d;
763 	ssize_t r;
764 
765 	while (c->len > 0) {
766 		switch (r = tls_write(c->ctx, c->sbuf + c->off, c->len)) {
767 		case -1:
768 			close_conn(fd, ev, c);
769 			return;
770 		case TLS_WANT_POLLOUT:
771 			reschedule_read(fd, c, &handle_dirlist);
772 			return;
773 		case TLS_WANT_POLLIN:
774 			reschedule_write(fd, c, &handle_dirlist);
775 			return;
776 		default:
777 			c->off += r;
778 			c->len -= r;
779 		}
780 	}
781 
782 	send_directory_listing(fd, ev, c);
783 }
784 
785 static int
786 read_next_dir_entry(struct client *c)
787 {
788 	struct dirent *d;
789 
790 	do {
791 		errno = 0;
792 		if ((d = readdir(c->dir)) == NULL) {
793 			if (errno != 0)
794 				log_err(c, "readdir: %s", strerror(errno));
795 			return 0;
796 		}
797 	} while (!strcmp(d->d_name, "."));
798 
799 	/* XXX: url escape */
800 	snprintf(c->sbuf, sizeof(c->sbuf), "=> %s %s\n",
801 	    d->d_name, d->d_name);
802 	c->len = strlen(c->sbuf);
803 	c->off = 0;
804 
805 	return 1;
806 }
807 
808 static void
809 send_directory_listing(int fd, short ev, void *d)
810 {
811 	struct client *c = d;
812 	ssize_t r;
813 
814 	while (1) {
815 		if (c->len == 0) {
816 			if (!read_next_dir_entry(c))
817 				goto end;
818 		}
819 
820 		while (c->len > 0) {
821 			switch (r = tls_write(c->ctx, c->sbuf + c->off, c->len)) {
822 			case -1:
823 				goto end;
824 
825 			case TLS_WANT_POLLOUT:
826 				reschedule_read(fd, c, &send_directory_listing);
827 				return;
828 
829 			case TLS_WANT_POLLIN:
830 				reschedule_write(fd, c, &send_directory_listing);
831 				return;
832 
833 			default:
834 				c->off += r;
835 				c->len -= r;
836 				break;
837 			}
838 		}
839 	}
840 
841 end:
842 	close_conn(fd, ev, d);
843 }
844 
845 /* accumulate the meta line from the cgi script. */
846 static void
847 handle_cgi_reply(int fd, short ev, void *d)
848 {
849 	struct client *c = d;
850 	void	*buf, *e;
851 	size_t	 len;
852 	ssize_t	 r;
853 
854 
855 	buf = c->sbuf + c->len;
856 	len = sizeof(c->sbuf) - c->len;
857 
858 	r = read(c->pfd, buf, len);
859 	if (r == 0 || r == -1) {
860 		start_reply(c, CGI_ERROR, "CGI error");
861 		return;
862 	}
863 
864 	c->len += r;
865 
866 	/* TODO: error if the CGI script don't reply correctly */
867 	e = strchr(c->sbuf, '\n');
868 	if (e != NULL || c->len == sizeof(c->sbuf)) {
869 		log_request(c, c->sbuf, c->len);
870 
871 		c->off = 0;
872 		handle_cgi(fd, ev, c);
873 		return;
874 	}
875 
876 	reschedule_read(fd, c, &handle_cgi_reply);
877 }
878 
879 static void
880 handle_cgi(int fd, short ev, void *d)
881 {
882 	struct client *c = d;
883 	ssize_t r;
884 
885 	while (1) {
886 		if (c->len == 0) {
887 			switch (r = read(c->pfd, c->sbuf, sizeof(c->sbuf))) {
888 			case 0:
889 				goto end;
890 			case -1:
891 				if (errno == EAGAIN || errno == EWOULDBLOCK) {
892 					reschedule_read(c->pfd, c, &handle_cgi);
893 					return;
894 				}
895 				goto end;
896 			default:
897 				c->len = r;
898 				c->off = 0;
899 			}
900 		}
901 
902 		while (c->len > 0) {
903 			switch (r = tls_write(c->ctx, c->sbuf + c->off, c->len)) {
904 			case -1:
905 				goto end;
906 
907 			case TLS_WANT_POLLOUT:
908 				reschedule_read(c->fd, c, &handle_cgi);
909 				return;
910 
911 			case TLS_WANT_POLLIN:
912 				reschedule_write(c->fd, c, &handle_cgi);
913 				return;
914 
915 			default:
916                                 c->off += r;
917 				c->len -= r;
918 				break;
919 			}
920 		}
921 	}
922 
923 end:
924 	close_conn(c->fd, ev, d);
925 }
926 
927 static void
928 close_conn(int fd, short ev, void *d)
929 {
930 	struct client *c = d;
931 
932 	switch (tls_close(c->ctx)) {
933 	case TLS_WANT_POLLIN:
934 		reschedule_read(fd, c, &close_conn);
935 		return;
936 	case TLS_WANT_POLLOUT:
937 		reschedule_read(fd, c, &close_conn);
938 		return;
939 	}
940 
941 	connected_clients--;
942 
943 	tls_free(c->ctx);
944 	c->ctx = NULL;
945 
946 	if (c->buf != MAP_FAILED)
947 		munmap(c->buf, c->len);
948 
949 	if (c->pfd != -1)
950 		close(c->pfd);
951 
952 	if (c->dir != NULL)
953 		closedir(c->dir);
954 
955 	close(c->fd);
956 	c->fd = -1;
957 }
958 
959 static void
960 do_accept(int sock, short et, void *d)
961 {
962 	struct client *c;
963 	struct server *s = d;
964 	struct sockaddr_storage addr;
965 	struct sockaddr *saddr;
966 	socklen_t len;
967 	int i, fd;
968 
969 	(void)et;
970 
971 
972 	saddr = (struct sockaddr*)&addr;
973 	len = sizeof(addr);
974 	if ((fd = accept4(sock, saddr, &len, SOCK_NONBLOCK)) == -1) {
975 		if (errno == EWOULDBLOCK || errno == EAGAIN)
976 			return;
977 		fatal("accept: %s", strerror(errno));
978 	}
979 
980 	for (i = 0; i < MAX_USERS; ++i) {
981 		c = &s->clients[i];
982 		if (c->fd == -1) {
983 			memset(c, 0, sizeof(*c));
984 			if (tls_accept_socket(s->ctx, &c->ctx, fd) == -1)
985 				break; /* goodbye fd! */
986 
987 			c->fd = fd;
988 			c->pfd = -1;
989 			c->buf = MAP_FAILED;
990 			c->dir = NULL;
991 			c->addr = addr;
992 
993 			reschedule_read(fd, c, &handle_handshake);
994 			connected_clients++;
995 			return;
996 		}
997 	}
998 
999 	close(fd);
1000 }
1001 
1002 static void
1003 handle_sighup(int fd, short ev, void *d)
1004 {
1005 	struct server_events *events = d;
1006 
1007 	(void)fd;
1008 	(void)ev;
1009 
1010 	event_del(&events->e4);
1011 	if (events->has_ipv6)
1012 		event_del(&events->e6);
1013 	signal_del(&events->sighup);
1014 }
1015 
1016 static void
1017 handle_siginfo(int fd, short ev, void *d)
1018 {
1019 	(void)fd;
1020 	(void)ev;
1021 	(void)d;
1022 
1023 	log_info(NULL, "%d connected clients", connected_clients);
1024 }
1025 
1026 void
1027 loop(struct tls *ctx, int sock4, int sock6)
1028 {
1029 	struct server_events events;
1030 	struct server server;
1031 	struct event info;
1032 	size_t i;
1033 
1034 	event_init();
1035 
1036 	memset(&events, 0, sizeof(events));
1037 	memset(&server, 0, sizeof(server));
1038 	for (i = 0; i < MAX_USERS; ++i)
1039 		server.clients[i].fd = -1;
1040 
1041 	event_set(&events.e4, sock4, EV_READ | EV_PERSIST, &do_accept, &server);
1042 	event_add(&events.e4, NULL);
1043 
1044 	if (sock6 != -1) {
1045 		events.has_ipv6 = 1;
1046 		event_set(&events.e6, sock6, EV_READ | EV_PERSIST, &do_accept, &server);
1047 		event_add(&events.e6, NULL);
1048 	}
1049 
1050 	signal_set(&events.sighup, SIGHUP, &handle_sighup, &events);
1051 	signal_add(&events.sighup, NULL);
1052 
1053 #ifdef SIGINFO
1054 	signal_set(&info, SIGINFO, &handle_siginfo, NULL);
1055 	signal_add(&info, NULL);
1056 #endif
1057 	signal_set(&info, SIGUSR2, &handle_siginfo, NULL);
1058 	signal_add(&info, NULL);
1059 
1060 	server.ctx = ctx;
1061 
1062 	event_dispatch();
1063 }