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Date:: Fri Nov 11 19:07:22 2022 UTC
Message:: links: use URL if label is made only of blanks thanks cage for unknowingly making me realize this edge case.
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1 /*
2  * Copyright (c) 2022 Omar Polo <op@omarpolo.com>
3  * Copyright (c) 2006 - 2015 Reyk Floeter <reyk@openbsd.org>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #include <sys/types.h>
19 #include <sys/queue.h>
20 #include <sys/tree.h>
21 #include <sys/socket.h>
22 #include <sys/uio.h>
23 
24 #include <netinet/in.h>
25 #include <arpa/inet.h>
26 #include <netdb.h>
27 
28 #include <asr.h>
29 #include <ctype.h>
30 #include <errno.h>
31 #include <event.h>
32 #include <fnmatch.h>
33 #include <limits.h>
34 #include <stdlib.h>
35 #include <stdint.h>
36 #include <stdio.h>
37 #include <string.h>
38 #include <imsg.h>
39 #include <tls.h>
40 #include <unistd.h>
41 
42 #include "config.h"
43 #include "log.h"
44 #include "proc.h"
45 #include "tmpl.h"
46 
47 #include "galileo.h"
48 
49 #define MINIMUM(a, b)	((a) < (b) ? (a) : (b))
50 
51 #if HAVE_LIBEVENT2
52 # define G_TOUT(t)	((t).tv_sec)
53 #else
54 # define G_TOUT(t)	(t)
55 #endif
56 
57 /* provided by OpenBSD' base libevent but not in any header? */
58 extern void	 bufferevent_read_pressure_cb(struct evbuffer *, size_t,
59 		    size_t, void *);
60 
61 void	proxy_init(struct privsep *, struct privsep_proc *, void *);
62 int	proxy_launch(struct galileo *);
63 void	proxy_inflight_dec(const char *);
64 int	proxy_dispatch_parent(int, struct privsep_proc *, struct imsg *);
65 int	proxy_resurl(struct client *, const char *, char *, size_t);
66 void	proxy_translate_gemtext(struct client *);
67 void	proxy_resolved(struct asr_result *, void *);
68 void	proxy_connect(int, short, void *);
69 int	proxy_start_reply(struct client *, int, const char *);
70 void	proxy_read(struct bufferevent *, void *);
71 void	proxy_write(struct bufferevent *, void *);
72 void	proxy_error(struct bufferevent *, short, void *);
73 int	proxy_bufferevent_add(struct event *, int);
74 void	proxy_tls_writecb(int, short, void *);
75 void	proxy_tls_readcb(int, short, void *);
76 
77 static struct privsep_proc procs[] = {
78 	{ "parent",	PROC_PARENT, proxy_dispatch_parent },
79 };
80 
81 volatile int proxy_clients;
82 volatile int proxy_inflight;
83 uint32_t proxy_fcg_id;
84 
85 void
86 proxy(struct privsep *ps, struct privsep_proc *p)
87 {
88 	proc_run(ps, p, procs, nitems(procs), proxy_init, NULL);
89 }
90 
91 void
92 proxy_init(struct privsep *ps, struct privsep_proc *p, void *arg)
93 {
94 	if (config_init(ps->ps_env) == -1)
95 		fatal("failed to initialize configuration");
96 
97 	/* We use a custom shutdown callback */
98 	/* p->p_shutdown = proxy_shutdown */
99 
100 	if (pledge("stdio recvfd unix inet dns", NULL) == -1)
101 		fatal("pledge");
102 }
103 
104 int
105 proxy_launch(struct galileo *env)
106 {
107 	event_add(&env->sc_evsock, NULL);
108 	return (0);
109 }
110 
111 void
112 proxy_purge(struct proxy *pr)
113 {
114 	free(pr);
115 }
116 
117 void
118 proxy_inflight_dec(const char *why)
119 {
120 	proxy_inflight--;
121 	log_debug("%s: inflight decremented, now %d, %s",
122 	    __func__, proxy_inflight, why);
123 }
124 
125 int
126 proxy_dispatch_parent(int fd, struct privsep_proc *p, struct imsg *imsg)
127 {
128 	struct privsep	*ps = p->p_ps;
129 	struct galileo	*env = ps->ps_env;
130 
131 	switch (imsg->hdr.type) {
132 	case IMSG_CFG_SRV:
133 		if (config_getproxy(env, imsg) == -1)
134 			fatal("config_getproxy");
135 		break;
136 	case IMSG_CFG_SOCK:
137 		/* XXX: improve */
138 
139 		env->sc_sock_fd = config_getsock(env, imsg);
140 		if (env->sc_sock_fd == -1)
141 			fatal("config_getsock");
142 
143 		event_set(&env->sc_evsock, env->sc_sock_fd,
144 		    EV_READ | EV_PERSIST, fcgi_accept, env);
145 		evtimer_set(&env->sc_evpause, fcgi_accept, env);
146 		break;
147 	case IMSG_CFG_DONE:
148 		config_getcfg(env, imsg);
149 		proxy_launch(env);
150 		break;
151 	case IMSG_CTL_START:
152 		break;
153 	case IMSG_CTL_RESET:
154 		config_getreset(env, imsg);
155 		break;
156 	default:
157 		return (-1);
158 	}
159 
160 	return (0);
161 }
162 
163 static int
164 portok(const char **url, struct client *clt)
165 {
166 	const char		*u = *url;
167 	const char		*port = clt->clt_pc->proxy_port;
168 	size_t			 len;
169 
170 	len = strlen(port);
171 
172 	if (*u == '\0' || *u == '/' || *u == '?' || *u == '#')
173 		return (1);
174 	if (*u != ':')
175 		return (0);
176 	u++;
177 	if (strncmp(u, port, len) != 0)
178 		return (0);
179 	u += len;
180 	if (*u != '\0' && *u != '/' && *u != '?' && *u != '#')
181 		return (0);
182 	*url = u;
183 	return (1);
184 }
185 
186 int
187 proxy_resurl(struct client *clt, const char *url, char *buf, size_t len)
188 {
189 	const char		*tmp;
190 	size_t			 l;
191 
192 	l = strlen(clt->clt_server_name);
193 
194 	if (len == 0) {
195 		log_warn("%s: zero-sized buffer!", __func__);
196 		return (-1);
197 	}
198 
199 	/* look if it's an absolute URI */
200 	if (strncmp(url, "//", 2) == 0) {
201 		tmp = url + 2;
202 		if (strncmp(tmp, clt->clt_server_name, l) != 0)
203 			goto done;
204 
205 		tmp += l;
206 		if (!portok(&tmp, clt))
207 			goto done;
208 		url = tmp;
209 	} else if (strncmp(url, "gemini://", 9) == 0) {
210 		tmp = url + 9;
211 		if (strncmp(tmp, clt->clt_server_name, l) != 0)
212 			goto done;
213 
214 		tmp += l;
215 		if (!portok(&tmp, clt))
216 			goto done;
217 		url = tmp;
218 	} else {
219 		tmp = url;
220 		while (isalpha((unsigned char)*tmp) || *tmp == '+')
221 			tmp++;
222 		if (strncmp(tmp, "://", 3) == 0)
223 			goto done;
224 	}
225 
226 	/* maybe it's an absolute path? */
227 	if (*url == '\0' || *url == '/') {
228 		if (strlcpy(buf, clt->clt_script_name, len) >= len)
229 			return (-1);
230 		if (strlcat(buf, url + 1, len) >= len)
231 			return (-1);
232 		return (0);
233 	}
234 
235 	/* otherwise, leave it as it is */
236  done:
237 	if (strlcpy(buf, url, len) >= len)
238 		return (-1);
239 	return (0);
240 }
241 
242 static int
243 gemtext_translate_line(struct client *clt, char *line)
244 {
245 	char		 buf[1025];
246 	char		*url;
247 
248 	/* preformatted line / closing */
249 	if (clt->clt_translate & TR_PRE) {
250 		if (!strncmp(line, "```", 3)) {
251 			clt->clt_translate &= ~TR_PRE;
252 			return (tp_pre_close(clt->clt_tp));
253 		}
254 
255 		if (tp_htmlescape(clt->clt_tp, line) == -1)
256 			return (-1);
257 		return (clt_putc(clt, '\n'));
258 	}
259 
260 	/* bullet */
261 	if (!strncmp(line, "* ", 2)) {
262 		if (clt->clt_translate & TR_NAV) {
263 			if (clt_puts(clt, "</ul></nav>") == -1)
264 				return (-1);
265 			clt->clt_translate &= ~TR_NAV;
266 		}
267 
268 		if (!(clt->clt_translate & TR_LIST)) {
269 			if (clt_puts(clt, "<ul>") == -1)
270 				return (-1);
271 			clt->clt_translate |= TR_LIST;
272 		}
273 
274 		if (clt_puts(clt, "<li>") == -1 ||
275 		    tp_htmlescape(clt->clt_tp, line + 2) == -1 ||
276 		    clt_puts(clt, "</li>") == -1)
277 			return (-1);
278 		return (0);
279 	}
280 
281 	if (clt->clt_translate & TR_LIST) {
282 		if (clt_puts(clt, "</ul>") == -1)
283 			return (-1);
284 		clt->clt_translate &= ~TR_LIST;
285 	}
286 
287 	/* link */
288 	if (!strncmp(line, "=>", 2)) {
289 		char *label;
290 
291 		line += 2;
292 		line += strspn(line, " \t");
293 
294 		label = line + strcspn(line, " \t");
295 		if (*label == '\0')
296 			label = line;
297 		else {
298 			*label++ = '\0';
299 			label += strspn(label, " \t");
300 			if (*label == '\0')
301 				label = line;
302 		}
303 
304 		if (proxy_resurl(clt, line, buf, sizeof(buf)) == 0)
305 			url = buf;
306 		else
307 			url = line; /* leave the URL as it is */
308 
309 		if (fnmatch("*.jpg", url, 0) == 0 ||
310 		    fnmatch("*.jpeg", url, 0) == 0 ||
311 		    fnmatch("*.gif", url, 0) == 0 ||
312 		    fnmatch("*.png", url, 0) == 0 ||
313 		    fnmatch("*.svg", url, 0) == 0 ||
314 		    fnmatch("*.webp", url, 0) == 0) {
315 			if (clt->clt_translate & TR_NAV) {
316 				if (clt_puts(clt, "</ul></nav>") == -1)
317 					return (-1);
318 				clt->clt_translate &= ~TR_NAV;
319 			}
320 
321 			if (tp_figure(clt->clt_tp, url, label) == -1)
322 				return (-1);
323 
324 			return (0);
325 		}
326 
327 		if (!(clt->clt_translate & TR_NAV)) {
328 			if (clt_puts(clt, "<nav><ul>") == -1)
329 				return (-1);
330 			clt->clt_translate |= TR_NAV;
331 		}
332 
333 		if (clt_puts(clt, "<li><a href='") == -1)
334 			return (-1);
335 
336 		if (tp_urlescape(clt->clt_tp, url) == -1 ||
337 		    clt_puts(clt, "'>") == -1 ||
338 		    tp_htmlescape(clt->clt_tp, label) == -1 ||
339 		    clt_puts(clt, "</a></li>") == -1)
340 			return (-1);
341 
342 		return (0);
343 	}
344 
345 	if (clt->clt_translate & TR_NAV) {
346 		if (clt_puts(clt, "</ul></nav>") == -1)
347 			return (-1);
348 		clt->clt_translate &= ~TR_NAV;
349 	}
350 
351 	/* pre opening */
352 	if (!strncmp(line, "```", 3)) {
353 		line += 3;
354 		line += strspn(line, " \t");
355 
356 		clt->clt_translate |= TR_PRE;
357 		return (tp_pre_open(clt->clt_tp, line));
358 	}
359 
360 	/* citation block */
361 	if (*line == '>') {
362 		if (clt_puts(clt, "<blockquote>") == -1 ||
363 		    tp_htmlescape(clt->clt_tp, line + 1) == -1 ||
364 		    clt_puts(clt, "</blockquote>") == -1)
365 			return (-1);
366 		return (0);
367 	}
368 
369 	/* headings */
370 	if (!strncmp(line, "###", 3)) {
371 		if (clt_puts(clt, "<h3>") == -1 ||
372 		    tp_htmlescape(clt->clt_tp, line + 3) == -1 ||
373 		    clt_puts(clt, "</h3>") == -1)
374 			return (-1);
375 		return (0);
376 	}
377 	if (!strncmp(line, "##", 2)) {
378 		if (clt_puts(clt, "<h2>") == -1 ||
379 		    tp_htmlescape(clt->clt_tp, line + 2) == -1 ||
380 		    clt_puts(clt, "</h2>") == -1)
381 			return (-1);
382 		return (0);
383 	}
384 	if (!strncmp(line, "#", 1)) {
385 		if (clt_puts(clt, "<h1>") == -1 ||
386 		    tp_htmlescape(clt->clt_tp, line + 1) == -1 ||
387 		    clt_puts(clt, "</h1>") == -1)
388 			return (-1);
389 		return (0);
390 	}
391 
392 	/* Not following strictly the gemini specification... */
393 	if (*line == '\0')
394 		return (0);
395 
396 	/* paragraph */
397 	if (clt_puts(clt, "<p>") == -1 ||
398 	    tp_htmlescape(clt->clt_tp, line) == -1 ||
399 	    clt_puts(clt, "</p>") == -1)
400 		return (-1);
401 
402 	return (0);
403 }
404 
405 void
406 proxy_translate_gemtext(struct client *clt)
407 {
408 	struct bufferevent	*bev = clt->clt_bev;
409 	struct evbuffer		*src = EVBUFFER_INPUT(bev);
410 	char			*line;
411 	size_t			 len;
412 	int			 r;
413 
414 	for (;;) {
415 		line = evbuffer_readln(src, &len, EVBUFFER_EOL_CRLF);
416 		if (line == NULL)
417 			return;
418 
419 		r = gemtext_translate_line(clt, line);
420 		free(line);
421 		if (r == -1)
422 			return;
423 	}
424 }
425 
426 struct proxy_config *
427 proxy_match(struct galileo *env, const char *name)
428 {
429 	struct proxy		*pr;
430 
431 	if (name == NULL)
432 		return (NULL);
433 
434 	TAILQ_FOREACH(pr, &env->sc_proxies, pr_entry) {
435 		if (!strcmp(name, pr->pr_conf.host))
436 			return (&pr->pr_conf);
437 	}
438 
439 	return (NULL);
440 }
441 
442 int
443 proxy_start_request(struct galileo *env, struct client *clt)
444 {
445 	struct addrinfo		 hints;
446 	struct asr_query	*query;
447 	int			 r;
448 	char			*url;
449 
450 	if (clt->clt_path_info == NULL) {
451 		log_warnx("PATH_INFO not defined!");
452 		if (proxy_start_reply(clt, 501, "text/html") == -1)
453 			return (-1);
454 		if (tp_error(clt->clt_tp, -1, "internal server error") == -1)
455 			return (-1);
456 		return (fcgi_end_request(clt, 1));
457 	}
458 
459 	if ((clt->clt_pc = proxy_match(env, clt->clt_server_name)) == NULL) {
460 		if (proxy_start_reply(clt, 501, "text/html") == -1)
461 			return (-1);
462 		if (tp_error(clt->clt_tp, -1, "unknown server") == -1)
463 			return (-1);
464 		return (fcgi_end_request(clt, 1));
465 	}
466 
467 	if (clt->clt_bodylen != 0 && clt->clt_body == NULL) {
468 		if (proxy_start_reply(clt, 400, "text/html") == -1)
469 			return (-1);
470 		if (tp_error(clt->clt_tp, -1, "bad request") == -1)
471 			return (-1);
472 		return (fcgi_end_request(clt, 1));
473 	}
474 
475 	if (clt->clt_body) {
476 		r = asprintf(&url, "%s%s?%s", clt->clt_script_name,
477 		    clt->clt_path_info + 1, clt->clt_body);
478 		if (r == -1)
479 			return (fcgi_end_request(clt, 1));
480 
481 		if (proxy_start_reply(clt, 302, url) == -1 ||
482 		    fcgi_end_request(clt, 1) == -1) {
483 			free(url);
484 			return (-1);
485 		}
486 		free(url);
487 		return (0);
488 	}
489 
490 	memset(&hints, 0, sizeof(hints));
491 	hints.ai_family = AF_UNSPEC;
492 	hints.ai_socktype = SOCK_STREAM;
493 
494 	query = getaddrinfo_async(clt->clt_pc->proxy_addr,
495 	    clt->clt_pc->proxy_port, &hints, NULL);
496 	if (query == NULL) {
497 		log_warn("getaddrinfo_async");
498 		return (fcgi_abort_request(clt));
499 	}
500 
501 	clt->clt_evasr = event_asr_run(query, proxy_resolved, clt);
502 	if (clt->clt_evasr == NULL) {
503 		log_warn("event_asr_run");
504 		asr_abort(query);
505 		return (fcgi_abort_request(clt));
506 	}
507 
508 	return (0);
509 }
510 
511 void
512 proxy_resolved(struct asr_result *res, void *d)
513 {
514 	struct client		*clt = d;
515 	struct proxy_config	*pc = clt->clt_pc;
516 
517 	clt->clt_evasr = NULL;
518 
519 	if (res->ar_gai_errno != 0) {
520 		log_warnx("failed to resolve %s:%s: %s",
521 		    pc->proxy_addr, pc->proxy_port,
522 		    gai_strerror(res->ar_gai_errno));
523 		if (proxy_start_reply(clt, 501, "text/html") == -1)
524 			return;
525 		if (tp_error(clt->clt_tp, -1, "Can't resolve host") == -1)
526 			return;
527 		fcgi_end_request(clt, 1);
528 		return;
529 	}
530 
531 	clt->clt_addrinfo = res->ar_addrinfo;
532 	clt->clt_p = clt->clt_addrinfo;
533 	proxy_connect(-1, 0, clt);
534 }
535 
536 void
537 proxy_connect(int fd, short ev, void *d)
538 {
539 	struct client		*clt = d;
540 	struct evbuffer		*out;
541 	struct addrinfo		*p;
542 	struct tls_config	*conf;
543 	struct timeval		 conntv = {5, 0};
544 	int			 err = 0;
545 	socklen_t		 len = sizeof(err);
546 
547 again:
548 	if (clt->clt_p == NULL)
549 		goto err;
550 
551 	if (clt->clt_fd != -1) {
552 		if (getsockopt(clt->clt_fd, SOL_SOCKET, SO_ERROR, &err, &len)
553 		    == -1)
554 			goto err;
555 		if (err != 0) {
556 			errno = err;
557 			goto err;
558 		}
559 		goto done;
560 	}
561 
562 	p = clt->clt_p;
563 	clt->clt_fd = socket(p->ai_family, p->ai_socktype | SOCK_NONBLOCK,
564 	    p->ai_protocol);
565 	if (clt->clt_fd == -1) {
566 		clt->clt_p = clt->clt_p->ai_next;
567 		goto again;
568 	}
569 
570 	if (connect(clt->clt_fd, p->ai_addr, p->ai_addrlen) == 0)
571 		goto done;
572 
573 	clt->clt_evconn_live = 1;
574 	event_set(&clt->clt_evconn, clt->clt_fd, EV_WRITE, proxy_connect, clt);
575 	event_add(&clt->clt_evconn, &conntv);
576 	return;
577 
578 done:
579 	clt->clt_evconn_live = 0;
580 	freeaddrinfo(clt->clt_addrinfo);
581 	clt->clt_addrinfo = clt->clt_p = NULL;
582 
583 	clt->clt_bev = bufferevent_new(clt->clt_fd, proxy_read, proxy_write,
584 	    proxy_error, clt);
585 	if (clt->clt_bev == NULL) {
586 		log_warn("bufferevent_new");
587 		goto err;
588 	}
589 
590 	if (!clt->clt_pc->no_tls) {
591 		/* initialize TLS for Gemini */
592 		if ((conf = tls_config_new()) == NULL) {
593 			log_warn("tls_config_new failed");
594 			goto err;
595 		}
596 
597 		tls_config_insecure_noverifycert(conf);
598 
599 		if ((clt->clt_ctx = tls_client()) == NULL) {
600 			log_warnx("tls_client failed");
601 			tls_config_free(conf);
602 			goto err;
603 		}
604 
605 		if (tls_configure(clt->clt_ctx, conf) == -1) {
606 			log_warnx("tls_configure failed");
607 			tls_config_free(conf);
608 			goto err;
609 		}
610 
611 		tls_config_free(conf);
612 
613 		if (tls_connect_socket(clt->clt_ctx, clt->clt_fd,
614 			clt->clt_pc->proxy_name) == -1) {
615 			log_warnx("tls_connect_socket failed");
616 			goto err;
617 		}
618 
619 		event_set(&clt->clt_bev->ev_read, clt->clt_fd, EV_READ,
620 		    proxy_tls_readcb, clt->clt_bev);
621 		event_set(&clt->clt_bev->ev_write, clt->clt_fd, EV_WRITE,
622 		    proxy_tls_writecb, clt->clt_bev);
623 
624 #if HAVE_LIBEVENT2
625 		evbuffer_unfreeze(clt->clt_bev->input, 0);
626 		evbuffer_unfreeze(clt->clt_bev->output, 1);
627 #endif
628 	}
629 
630 	/* bufferevent_settimeout(); */
631 	bufferevent_enable(clt->clt_bev, EV_READ|EV_WRITE);
632 
633 	/* TODO: compute the URL */
634 	out = EVBUFFER_OUTPUT(clt->clt_bev);
635 	if (evbuffer_add_printf(out, "gemini://%s/%s",
636 	    clt->clt_pc->proxy_name, clt->clt_path_info) == -1) {
637 		log_warn("bufferevent_printf failed");
638 		goto err;
639 	}
640 
641 	if (clt->clt_query &&
642 	    evbuffer_add_printf(out, "?%s", clt->clt_query) == -1) {
643 		log_warn("bufferevent_printf failed");
644 		goto err;
645 	}
646 
647 	if (evbuffer_add(out, "\r\n", 2) == -1) {
648 		log_warn("bufferevent_add failed");
649 		goto err;
650 	}
651 
652 	return;
653 
654 err:
655 	log_warn("failed to connect to %s:%s",
656 	    clt->clt_pc->proxy_addr, clt->clt_pc->proxy_port);
657 	if (proxy_start_reply(clt, 501, "text/html") == -1)
658 		return;
659 	if (tp_error(clt->clt_tp, -1, "Can't connect") == -1)
660 		return;
661 	fcgi_end_request(clt, 1);
662 }
663 
664 static inline int
665 parse_mime(struct client *clt, char *mime, char *lang, size_t len)
666 {
667 	char			*t, *semi;
668 
669 	if (strncmp(mime, "text/gemini", 11) != 0)
670 		return (0);
671 
672 	clt->clt_translate = TR_ENABLED;
673 
674 	if ((mime = strchr(mime, ';')) == NULL)
675 		return (0);
676 
677 	*mime++ = '\0';
678 	while ((t = strsep(&mime, ";")) != NULL) {
679 		if (!strncmp(t, "charset=", 8)) {
680 			t += 8;
681 			if (!strncasecmp(t, "utf8", 4) ||
682 			    !strncasecmp(t, "utf-8", 5) ||
683 			    !strncasecmp(t, "ascii", 5)) {
684 				log_debug("unknown charset %s", t);
685 				return (-1);
686 			}
687 			continue;
688 		}
689 
690 		if (!strncmp(t, "lang=", 5)) {
691 			t += 5;
692 			if ((semi = strchr(t, ';')) != NULL)
693 				*semi = '\0';
694 
695 			if (strlcpy(lang, t, len) >= len) {
696 				log_debug("lang too long: %s", t);
697 				*lang = '\0';
698 			}
699 
700 			if (semi)
701 				*semi = ';';
702 			continue;
703 		}
704 	}
705 
706 	return (0);
707 }
708 
709 int
710 proxy_start_reply(struct client *clt, int status, const char *ctype)
711 {
712 	const char	*csp;
713 
714 	csp = "Content-Security-Policy: default-src 'self'; "
715 	    "script-src 'none'; object-src 'none';\r\n";
716 
717 	if (status != 200 &&
718 	    clt_printf(clt, "Status: %d\r\n", status) == -1)
719 		return (-1);
720 
721 	if (clt_puts(clt, csp) == -1)
722 		return (-1);
723 
724 	if (status == 302) {
725 		/* use "ctype" as redirect target */
726 		if (clt_printf(clt, "Location: %s\r\n", ctype) == -1)
727 			return (-1);
728 		if (clt_puts(clt, "\r\n") == -1)
729 			return (-1);
730 		return (0);
731 	}
732 
733 	if (ctype != NULL) {
734 		if (!strcmp(ctype, "text/html"))
735 			ctype = "text/html;charset=utf-8";
736 		if (clt_printf(clt, "Content-Type: %s\r\n", ctype)
737 		    == -1)
738 			return (-1);
739 	}
740 
741 	if (clt_puts(clt, "\r\n") == -1)
742 		return (-1);
743 
744 	return (0);
745 }
746 
747 void
748 proxy_read(struct bufferevent *bev, void *d)
749 {
750 	struct client		*clt = d;
751 	struct evbuffer		*src = EVBUFFER_INPUT(bev);
752 	const char		*ctype;
753 	char			 buf[1025];
754 	char			 lang[16];
755 	char			*hdr, *mime;
756 	size_t			 len;
757 	int			 code;
758 
759 	if (clt->clt_headersdone) {
760 		if (clt->clt_translate)
761 			proxy_translate_gemtext(clt);
762 		else
763 			clt_write_bufferevent(clt, bev);
764 		return;
765 	}
766 
767 	hdr = evbuffer_readln(src, &len, EVBUFFER_EOL_CRLF_STRICT);
768 	if (hdr == NULL) {
769 		if (EVBUFFER_LENGTH(src) >= 1026)
770 			proxy_error(bev, EV_READ, clt);
771 		return;
772 	}
773 
774 	if (len < 4 ||
775 	    !isdigit((unsigned char)hdr[0]) ||
776 	    !isdigit((unsigned char)hdr[1]) ||
777 	    hdr[2] != ' ') {
778 		log_warnx("invalid ");
779 		proxy_error(bev, EV_READ, clt);
780 		goto err;
781 	}
782 
783 	code = (hdr[0] - '0') * 10 + (hdr[1] - '0');
784 
785 	switch (hdr[0]) {
786 	case '1':
787 		if (proxy_start_reply(clt, 200, "text/html") == -1)
788 			goto err;
789 		if (tp_inputpage(clt->clt_tp, &hdr[3]) == -1)
790 			goto err;
791 		fcgi_end_request(clt, 0);
792 		goto err;
793 	case '2':
794 		/* handled below */
795 		break;
796 	case '3':
797 		if (proxy_resurl(clt, &hdr[3], buf, sizeof(buf)) == 0) {
798 			if (proxy_start_reply(clt, 302, buf) == -1)
799 				goto err;
800 			fcgi_end_request(clt, 0);
801 			goto err;
802 		}
803 		/* fallthrough */
804 	default:
805 		if (proxy_start_reply(clt, 501, "text/html") == -1)
806 			goto err;
807 		if (tp_error(clt->clt_tp, code, &hdr[3]) == -1)
808 			goto err;
809 		fcgi_end_request(clt, 1);
810 		goto err;
811 	}
812 
813 	mime = hdr + 2 + strspn(hdr + 2, " \t");
814 	if (parse_mime(clt, mime, lang, sizeof(lang)) == -1) {
815 		if (proxy_start_reply(clt, 501, "text/html") == -1)
816 			goto err;
817 		if (tp_error(clt->clt_tp, -1, "Bad response") == -1)
818 			goto err;
819 		fcgi_end_request(clt, 1);
820 		goto err;
821 	}
822 
823 	if (clt->clt_translate)
824 		ctype = "text/html;charset=utf-8";
825 	else
826 		ctype = mime;
827 
828 	if (clt_printf(clt, "Content-Type: %s\r\n\r\n", ctype) == -1)
829 		goto err;
830 
831 	clt->clt_headersdone = 1;
832 
833 	if (clt->clt_translate &&
834 	    tp_head(clt->clt_tp, lang, NULL) == -1)
835 		goto err;
836 
837 	/*
838 	 * Trigger the read again so we proceed with the response
839 	 * body, if any.
840 	 */
841 	free(hdr);
842 	proxy_read(bev, d);
843 	return;
844 
845 err:
846 	free(hdr);
847 }
848 
849 void
850 proxy_write(struct bufferevent *bev, void *d)
851 {
852 	return;
853 }
854 
855 void
856 proxy_error(struct bufferevent *bev, short err, void *d)
857 {
858 	struct client		*clt = d;
859 	int			 status = !(err & EVBUFFER_EOF);
860 
861 	log_debug("proxy error, shutting down the connection (err: %x)",
862 	    err);
863 
864 	if (!clt->clt_headersdone) {
865 		if (proxy_start_reply(clt, 501, "text/html") == -1)
866 			return;
867 		if (tp_error(clt->clt_tp, -1, "Proxy error") == -1)
868 			return;
869 	} else if (status == 0) {
870 		if (clt->clt_translate & TR_PRE) {
871 			if (tp_pre_close(clt->clt_tp))
872 				return;
873 			clt->clt_translate &= ~TR_PRE;
874 		}
875 
876 		if (clt->clt_translate & TR_LIST) {
877 			if (clt_puts(clt, "</ul>") == -1)
878 				return;
879 			clt->clt_translate &= ~TR_LIST;
880 		}
881 
882 		if (clt->clt_translate & TR_NAV) {
883 			if (clt_puts(clt, "</ul></nav>") == -1)
884 				return;
885 			clt->clt_translate &= ~TR_NAV;
886 		}
887 
888 		if (clt->clt_translate &&
889 		    tp_foot(clt->clt_tp) == -1)
890 			return;
891 	}
892 
893 	fcgi_end_request(clt, status);
894 }
895 
896 void
897 proxy_tls_readcb(int fd, short event, void *arg)
898 {
899 	struct bufferevent	*bufev = arg;
900 	struct client		*clt = bufev->cbarg;
901 	char			 rbuf[IBUF_READ_SIZE];
902 	int			 what = EVBUFFER_READ;
903 	int			 howmuch = IBUF_READ_SIZE;
904 	ssize_t			 ret;
905 	size_t			 len;
906 
907 	if (event == EV_TIMEOUT) {
908 		what |= EVBUFFER_TIMEOUT;
909 		goto err;
910 	}
911 
912 	if (bufev->wm_read.high != 0)
913 		howmuch = MINIMUM(sizeof(rbuf), bufev->wm_read.high);
914 
915 	ret = tls_read(clt->clt_ctx, rbuf, howmuch);
916 	if (ret == TLS_WANT_POLLIN || ret == TLS_WANT_POLLOUT) {
917 		goto retry;
918 	} else if (ret == -1) {
919 		what |= EVBUFFER_ERROR;
920 		goto err;
921 	}
922 	len = ret;
923 
924 	if (len == 0) {
925 		what |= EVBUFFER_EOF;
926 		goto err;
927 	}
928 
929 	if (evbuffer_add(bufev->input, rbuf, len) == -1) {
930 		what |= EVBUFFER_ERROR;
931 		goto err;
932 	}
933 
934 	proxy_bufferevent_add(&bufev->ev_read, G_TOUT(bufev->timeout_read));
935 
936 	len = EVBUFFER_LENGTH(bufev->input);
937 	if (bufev->wm_read.low != 0 && len < bufev->wm_read.low)
938 		return;
939 	if (bufev->wm_read.high != 0 && len > bufev->wm_read.high) {
940 		struct evbuffer *buf = bufev->input;
941 		event_del(&bufev->ev_read);
942 		evbuffer_setcb(buf, bufferevent_read_pressure_cb, bufev);
943 		return;
944 	}
945 
946 	if (bufev->readcb != NULL)
947 		(*bufev->readcb)(bufev, bufev->cbarg);
948 	return;
949 
950 retry:
951 	proxy_bufferevent_add(&bufev->ev_read, G_TOUT(bufev->timeout_read));
952 	return;
953 
954 err:
955 	(*bufev->errorcb)(bufev, what, bufev->cbarg);
956 }
957 
958 int
959 proxy_bufferevent_add(struct event *ev, int timeout)
960 {
961 	struct timeval tv, *ptv = NULL;
962 
963 	if (timeout) {
964 		timerclear(&tv);
965 		tv.tv_sec = timeout;
966 		ptv = &tv;
967 	}
968 
969 	return (event_add(ev, ptv));
970 }
971 
972 void
973 proxy_tls_writecb(int fd, short event, void *arg)
974 {
975 	struct bufferevent	*bufev = arg;
976 	struct client		*clt = bufev->cbarg;
977 	ssize_t			 ret;
978 	short			 what = EVBUFFER_WRITE;
979 	size_t			 len;
980 
981 	if (event == EV_TIMEOUT) {
982 		what |= EVBUFFER_TIMEOUT;
983 		goto err;
984 	}
985 
986 	if (EVBUFFER_LENGTH(bufev->output)) {
987 		ret = tls_write(clt->clt_ctx,
988 		    EVBUFFER_DATA(bufev->output),
989 		    EVBUFFER_LENGTH(bufev->output));
990 		if (ret == TLS_WANT_POLLIN || ret == TLS_WANT_POLLOUT) {
991 			goto retry;
992 		} else if (ret == -1) {
993 			what |= EVBUFFER_ERROR;
994 			goto err;
995 		}
996 		len = ret;
997 		evbuffer_drain(bufev->output, len);
998 	}
999 
1000 	if (EVBUFFER_LENGTH(bufev->output) != 0)
1001 		proxy_bufferevent_add(&bufev->ev_write,
1002 		    G_TOUT(bufev->timeout_write));
1003 
1004 	if (bufev->writecb != NULL &&
1005 	    EVBUFFER_LENGTH(bufev->output) <= bufev->wm_write.low)
1006 		(*bufev->writecb)(bufev, bufev->cbarg);
1007 	return;
1008 
1009 retry:
1010 	proxy_bufferevent_add(&bufev->ev_write, G_TOUT(bufev->timeout_write));
1011 	return;
1012 
1013 err:
1014 	(*bufev->errorcb)(bufev, what, bufev->cbarg);
1015 }
1016 
1017 void
1018 proxy_client_free(struct client *clt)
1019 {
1020 	if (clt->clt_evasr)
1021 		event_asr_abort(clt->clt_evasr);
1022 
1023 	if (clt->clt_addrinfo)
1024 		freeaddrinfo(clt->clt_addrinfo);
1025 
1026 	if (clt->clt_evconn_live)
1027 		event_del(&clt->clt_evconn);
1028 
1029 	if (clt->clt_fd != -1)
1030 		close(clt->clt_fd);
1031 
1032 	if (clt->clt_ctx)
1033 		tls_free(clt->clt_ctx);
1034 
1035 	if (clt->clt_bev)
1036 		bufferevent_free(clt->clt_bev);
1037 
1038 	template_free(clt->clt_tp);
1039 
1040 	free(clt->clt_body);
1041 	free(clt->clt_server_name);
1042 	free(clt->clt_script_name);
1043 	free(clt->clt_path_info);
1044 	free(clt->clt_query);
1045 	free(clt);
1046 }