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/socket.h>
18 
19 #include <errno.h>
20 #include <getopt.h>
21 #include <limits.h>
22 #include <signal.h>
23 #include <stdio.h>
24 #include <stdlib.h>
25 #include <string.h>
26 #include <unistd.h>
27 
28 #include "defaults.h"
29 #include "parser.h"
30 #include "telescope.h"
31 #include "ui.h"
32 
33 static struct option longopts[] = {
34 	{"colors",	no_argument,	NULL,	'c'},
35 	{"help",	no_argument,	NULL,	'h'},
36 	{"version",	no_argument,	NULL,	'v'},
37 	{NULL,		0,		NULL,	0},
38 };
39 
40 static const char *opts = "Cc:hnT:v";
41 
42 static struct imsgev	*iev_fs, *iev_net;
43 
44 struct tabshead		 tabshead = TAILQ_HEAD_INITIALIZER(tabshead);
45 struct proxylist	 proxies = TAILQ_HEAD_INITIALIZER(proxies);
46 
47 enum telescope_process {
48 	PROC_UI,
49 	PROC_FS,
50 	PROC_NET,
51 };
52 
53 /* the first is also the fallback one */
54 static struct proto protos[] = {
55 	{ "gemini",	load_gemini_url },
56 	{ "about",	load_about_url },
57 	{ NULL, NULL },
58 };
59 
60 
61 #define CANNOT_FETCH		0
62 #define TOO_MUCH_REDIRECTS	1
63 #define MALFORMED_RESPONSE	2
64 #define UNKNOWN_TYPE_OR_CSET	3
65 #define UNKNOWN_PROTOCOL	4
66 
67 /* XXX: keep in sync with telescope.c:/^normalize_code/ */
68 const char *err_pages[70] = {
69 	[CANNOT_FETCH]		= "# Couldn't load the page\n",
70 	[TOO_MUCH_REDIRECTS]	= "# Too much redirects\n",
71 	[MALFORMED_RESPONSE]	= "# Got a malformed response\n",
72 	[UNKNOWN_TYPE_OR_CSET]	= "# Unsupported type or charset\n",
73 	[UNKNOWN_PROTOCOL]	= "# Unknown protocol\n",
74 
75 	[10] = "# Input required\n",
76 	[11] = "# Input required\n",
77 	[40] = "# Temporary failure\n",
78 	[41] = "# Server unavailable\n",
79 	[42] = "# CGI error\n",
80 	[43] = "# Proxy error\n",
81 	[44] = "# Slow down\n",
82 	[50] = "# Permanent failure\n",
83 	[51] = "# Not found\n",
84 	[52] = "# Gone\n",
85 	[53] = "# Proxy request refused\n",
86 	[59] = "# Bad request\n",
87 	[60] = "# Client certificate required\n",
88 	[61] = "# Certificate not authorised\n",
89 	[62] = "# Certificate not valid\n"
90 };
91 
92 static void		 die(void) __attribute__((__noreturn__));
93 static struct tab	*tab_by_id(uint32_t);
94 static void		 handle_imsg_err(struct imsg*, size_t);
95 static void		 handle_imsg_check_cert(struct imsg*, size_t);
96 static void		 handle_check_cert_user_choice(int, struct tab *);
97 static void		 handle_maybe_save_new_cert(int, struct tab *);
98 static void		 handle_imsg_got_code(struct imsg*, size_t);
99 static void		 handle_imsg_got_meta(struct imsg*, size_t);
100 static void		 handle_maybe_save_page(int, struct tab *);
101 static void		 handle_save_page_path(const char *, struct tab *);
102 static void		 handle_imsg_file_opened(struct imsg*, size_t);
103 static void		 handle_imsg_buf(struct imsg*, size_t);
104 static void		 handle_imsg_eof(struct imsg*, size_t);
105 static void		 handle_imsg_bookmark_ok(struct imsg*, size_t);
106 static void		 handle_imsg_save_cert_ok(struct imsg*, size_t);
107 static void		 handle_imsg_update_cert_ok(struct imsg *, size_t);
108 static void		 handle_dispatch_imsg(int, short, void*);
109 static void		 load_page_from_str(struct tab*, const char*);
110 static int		 do_load_url(struct tab*, const char*);
111 static void		 parse_session_line(char *, const char **, uint32_t *);
112 static void		 load_last_session(void);
113 static pid_t		 start_child(enum telescope_process, const char *, int);
114 static int		 ui_send_net(int, uint32_t, const void *, uint16_t);
115 static int		 ui_send_fs(int, uint32_t, const void *, uint16_t);
116 
117 static imsg_handlerfn *handlers[] = {
118 	[IMSG_ERR] = handle_imsg_err,
119 	[IMSG_CHECK_CERT] = handle_imsg_check_cert,
120 	[IMSG_GOT_CODE] = handle_imsg_got_code,
121 	[IMSG_GOT_META] = handle_imsg_got_meta,
122 	[IMSG_BUF] = handle_imsg_buf,
123 	[IMSG_EOF] = handle_imsg_eof,
124 	[IMSG_BOOKMARK_OK] = handle_imsg_bookmark_ok,
125 	[IMSG_SAVE_CERT_OK] = handle_imsg_save_cert_ok,
126 	[IMSG_UPDATE_CERT_OK] = handle_imsg_update_cert_ok,
127 	[IMSG_FILE_OPENED] = handle_imsg_file_opened,
128 };
129 
130 static struct ohash	certs;
131 
132 static void __attribute__((__noreturn__))
133 die(void)
134 {
135 	abort(); 		/* TODO */
136 }
137 
138 static struct tab *
139 tab_by_id(uint32_t id)
140 {
141 	struct tab *t;
142 
143 	TAILQ_FOREACH(t, &tabshead, tabs) {
144 		if (t->id == id)
145 			return t;
146 	}
147 
148 	return NULL;
149 }
150 
151 static void
152 handle_imsg_err(struct imsg *imsg, size_t datalen)
153 {
154 	struct tab	*tab;
155 	char		*page;
156 
157 	if ((tab = tab_by_id(imsg->hdr.peerid)) == NULL)
158 		return;
159 
160 	page = imsg->data;
161 	page[datalen-1] = '\0';
162 
163 	if (asprintf(&page, "# Error loading %s\n\n> %s\n",
164 	    tab->hist_cur->h, page) == -1)
165 		die();
166 	load_page_from_str(tab, page);
167 	free(page);
168 }
169 
170 static void
171 handle_imsg_check_cert(struct imsg *imsg, size_t datalen)
172 {
173 	const char		*hash, *host, *port;
174 	int			 tofu_res;
175 	struct tofu_entry	*e;
176 	struct tab		*tab;
177 
178 	hash = imsg->data;
179 	if (hash[datalen-1] != '\0')
180 		abort();
181 
182 	if ((tab = tab_by_id(imsg->hdr.peerid)) == NULL)
183 		return;
184 
185 	if (tab->proxy != NULL) {
186 		host = tab->proxy->host;
187 		port = tab->proxy->port;
188 	} else {
189 		host = tab->uri.host;
190 		port = tab->uri.port;
191 	}
192 
193 	if ((e = tofu_lookup(&certs, host, port)) == NULL) {
194 		/* TODO: an update in libressl/libretls changed
195 		 * significantly.  Find a better approach at storing
196 		 * the certs! */
197 		if (datalen > sizeof(e->hash))
198 			abort();
199 
200 		tofu_res = 1;	/* trust on first use */
201 		if ((e = calloc(1, sizeof(*e))) == NULL)
202 			abort();
203 		strlcpy(e->domain, host, sizeof(e->domain));
204 		if (*port != '\0' && strcmp(port, "1965")) {
205 			strlcat(e->domain, ":", sizeof(e->domain));
206 			strlcat(e->domain, port, sizeof(e->domain));
207 		}
208 		strlcpy(e->hash, hash, sizeof(e->hash));
209 		tofu_add(&certs, e);
210 		ui_send_fs(IMSG_SAVE_CERT, tab->id, e, sizeof(*e));
211 	} else
212 		tofu_res = !strcmp(hash, e->hash);
213 
214 	if (tofu_res) {
215 		if (e->verified == -1)
216 			tab->trust = TS_TEMP_TRUSTED;
217 		else if (e->verified == 1)
218 			tab->trust = TS_VERIFIED;
219 		else
220 			tab->trust = TS_TRUSTED;
221 
222 		ui_send_net(IMSG_CERT_STATUS, imsg->hdr.peerid,
223 		    &tofu_res, sizeof(tofu_res));
224 	} else {
225 		tab->trust = TS_UNTRUSTED;
226 		load_page_from_str(tab, "# Certificate mismatch\n");
227 		if ((tab->cert = strdup(hash)) == NULL)
228 			die();
229 		ui_yornp("Certificate mismatch.  Proceed?",
230 		    handle_check_cert_user_choice, tab);
231 	}
232 }
233 
234 static void
235 handle_check_cert_user_choice(int accept, struct tab *tab)
236 {
237 	ui_send_net(IMSG_CERT_STATUS, tab->id, &accept,
238 	    sizeof(accept));
239 
240 	if (accept) {
241 		/*
242 		 * trust the certificate for this session only.  If
243 		 * the page results in a redirect while we're asking
244 		 * the user to save, we'll end up with an invalid
245 		 * tabid (one request == one tab id) and crash.  It
246 		 * also makes sense to save it for the current session
247 		 * if the user accepted it.
248 		 */
249 		tofu_temp_trust(&certs, tab->uri.host, tab->uri.port, tab->cert);
250 
251 		ui_yornp("Save the new certificate?",
252 		    handle_maybe_save_new_cert, tab);
253 	} else {
254 		free(tab->cert);
255 		tab->cert = NULL;
256 	}
257 }
258 
259 static void
260 handle_maybe_save_new_cert(int accept, struct tab *tab)
261 {
262 	struct tofu_entry *e;
263 	const char *host, *port;
264 
265 	if (tab->proxy != NULL) {
266 		host = tab->proxy->host;
267 		port = tab->proxy->port;
268 	} else {
269 		host = tab->uri.host;
270 		port = tab->uri.port;
271 	}
272 
273 	if (!accept)
274 		goto end;
275 
276 	if ((e = calloc(1, sizeof(*e))) == NULL)
277 		die();
278 
279 	strlcpy(e->domain, host, sizeof(e->domain));
280 	if (*port != '\0' && strcmp(port, "1965")) {
281 		strlcat(e->domain, ":", sizeof(e->domain));
282 		strlcat(e->domain, port, sizeof(e->domain));
283 	}
284 	strlcpy(e->hash, tab->cert, sizeof(e->hash));
285 	ui_send_fs(IMSG_UPDATE_CERT, 0, e, sizeof(*e));
286 
287 	tofu_update(&certs, e);
288 
289 	tab->trust = TS_TRUSTED;
290 
291 end:
292 	free(tab->cert);
293 	tab->cert = NULL;
294 }
295 
296 static inline int
297 normalize_code(int n)
298 {
299 	if (n < 20) {
300 		if (n == 10 || n == 11)
301 			return n;
302 		return 10;
303 	} else if (n < 30) {
304 		return 20;
305 	} else if (n < 40) {
306 		if (n == 30 || n == 31)
307 			return n;
308 		return 30;
309 	} else if (n < 50) {
310 		if (n <= 44)
311 			return n;
312 		return 40;
313 	} else if (n < 60) {
314 		if (n <= 53 || n == 59)
315 			return n;
316 		return 50;
317 	} else if (n < 70) {
318 		if (n <= 62)
319 			return n;
320 		return 60;
321 	} else
322 		return MALFORMED_RESPONSE;
323 }
324 
325 static void
326 handle_imsg_got_code(struct imsg *imsg, size_t datalen)
327 {
328 	struct tab	*tab;
329 
330 	if ((tab = tab_by_id(imsg->hdr.peerid)) == NULL)
331 		return;
332 
333 	if (sizeof(tab->code) != datalen)
334 		die();
335 
336 	memcpy(&tab->code, imsg->data, sizeof(tab->code));
337 	tab->code = normalize_code(tab->code);
338 	if (tab->code != 30 && tab->code != 31)
339 		tab->redirect_count = 0;
340 }
341 
342 static void
343 handle_imsg_got_meta(struct imsg *imsg, size_t datalen)
344 {
345 	struct tab	*tab;
346 
347 	if ((tab = tab_by_id(imsg->hdr.peerid)) == NULL)
348 		return;
349 
350 	if (sizeof(tab->meta) <= datalen)
351 		die();
352 
353 	memcpy(tab->meta, imsg->data, datalen);
354 
355 	if (tab->code < 10) {	/* internal errors */
356 		load_page_from_str(tab, err_pages[tab->code]);
357 	} else if (tab->code < 20) {	/* 1x */
358 		load_page_from_str(tab, err_pages[tab->code]);
359 		ui_require_input(tab, tab->code == 11);
360 	} else if (tab->code == 20) {
361 		if (setup_parser_for(tab)) {
362 			ui_send_net(IMSG_PROCEED, tab->id, NULL, 0);
363 		} else {
364 			load_page_from_str(tab, err_pages[UNKNOWN_TYPE_OR_CSET]);
365 			ui_yornp("Can't display page, wanna save?",
366 			    handle_maybe_save_page, tab);
367 		}
368 	} else if (tab->code < 40) { /* 3x */
369 		tab->redirect_count++;
370 
371 		/* TODO: make customizable? */
372 		if (tab->redirect_count > 5) {
373 			load_page_from_str(tab,
374 			    err_pages[TOO_MUCH_REDIRECTS]);
375 		} else
376 			do_load_url(tab, tab->meta);
377 	} else { /* 4x, 5x & 6x */
378 		load_page_from_str(tab, err_pages[tab->code]);
379 	}
380 }
381 
382 static void
383 handle_maybe_save_page(int dosave, struct tab *tab)
384 {
385 	if (dosave)
386 		ui_read("Save to path", handle_save_page_path, tab);
387 	else
388 		stop_tab(tab);
389 }
390 
391 static void
392 handle_save_page_path(const char *path, struct tab *tab)
393 {
394 	if (path == NULL) {
395 		stop_tab(tab);
396 		return;
397 	}
398 
399 	tab->path = strdup(path);
400 
401 	ui_send_fs(IMSG_FILE_OPEN, tab->id, path, strlen(path)+1);
402 }
403 
404 static void
405 handle_imsg_file_opened(struct imsg *imsg, size_t datalen)
406 {
407 	struct tab	*tab;
408 	char		*page;
409 	const char	*e;
410 	int		 l;
411 
412 	if ((tab = tab_by_id(imsg->hdr.peerid)) == NULL) {
413 		if (imsg->fd != -1)
414 			close(imsg->fd);
415 		return;
416 	}
417 
418 	if (imsg->fd == -1) {
419 		stop_tab(tab);
420 
421 		e = imsg->data;
422 		if (e[datalen-1] != '\0')
423 			die();
424 		l = asprintf(&page, "# Can't open file\n\n> %s: %s\n",
425 		    tab->path, e);
426 		if (l == -1)
427 			die();
428 		load_page_from_str(tab, page);
429 		free(page);
430 	} else {
431 		tab->fd = imsg->fd;
432 		ui_send_net(IMSG_PROCEED, tab->id, NULL, 0);
433 	}
434 }
435 
436 static void
437 handle_imsg_buf(struct imsg *imsg, size_t datalen)
438 {
439 	struct tab	*tab;
440 	int		 l;
441 	char		*page, buf[FMT_SCALED_STRSIZE] = {0};
442 
443 	if ((tab = tab_by_id(imsg->hdr.peerid)) == NULL)
444 		return;
445 
446 	tab->bytes += datalen;
447 	if (tab->fd == -1) {
448 		if (!tab->buffer.page.parse(&tab->buffer.page,
449 		    imsg->data, datalen))
450 			die();
451 	} else {
452 		write(tab->fd, imsg->data, datalen);
453 		fmt_scaled(tab->bytes, buf);
454 		l = asprintf(&page, "Saving to \"%s\"... (%s)\n",
455 		    tab->path,
456 		    buf);
457 		if (l == -1)
458 			die();
459 		load_page_from_str(tab, page);
460 		free(page);
461 	}
462 
463 	ui_on_tab_refresh(tab);
464 }
465 
466 static void
467 handle_imsg_eof(struct imsg *imsg, size_t datalen)
468 {
469 	struct tab	*tab;
470 	int		 l;
471 	char		*page, buf[FMT_SCALED_STRSIZE] = {0};
472 
473 	if ((tab = tab_by_id(imsg->hdr.peerid)) == NULL)
474 		return;
475 
476 	if (tab->fd == -1) {
477 		if (!tab->buffer.page.free(&tab->buffer.page))
478 			die();
479 	} else {
480 		fmt_scaled(tab->bytes, buf);
481 		l = asprintf(&page, "Saved to \"%s\" (%s)\n",
482 		    tab->path,
483 		    buf);
484 		if (l == -1)
485 			die();
486 		load_page_from_str(tab, page);
487 		free(page);
488 
489 		close(tab->fd);
490 		tab->fd = -1;
491 		free(tab->path);
492 		tab->path = NULL;
493 	}
494 
495 	ui_on_tab_refresh(tab);
496 	ui_on_tab_loaded(tab);
497 }
498 
499 static void
500 handle_imsg_bookmark_ok(struct imsg *imsg, size_t datalen)
501 {
502 	int res;
503 
504 	if (datalen != sizeof(res))
505 		die();
506 
507 	memcpy(&res, imsg->data, sizeof(res));
508 	if (res == 0)
509 		message("Added to bookmarks!");
510 	else
511 		message("Failed to add to bookmarks: %s",
512 		    strerror(res));
513 }
514 
515 static void
516 handle_imsg_save_cert_ok(struct imsg *imsg, size_t datalen)
517 {
518 	int res;
519 
520 	if (datalen != sizeof(res))
521 		die();
522 	memcpy(&res, imsg->data, datalen);
523 	if (res != 0)
524 		message("Failed to save the cert for: %s",
525 		    strerror(res));
526 }
527 
528 static void
529 handle_imsg_update_cert_ok(struct imsg *imsg, size_t datalen)
530 {
531 	int res;
532 
533 	if (datalen != sizeof(res))
534 		die();
535 	memcpy(&res, imsg->data, datalen);
536 	if (!res)
537 		message("Failed to update the certificate");
538 }
539 
540 static void
541 handle_dispatch_imsg(int fd, short ev, void *d)
542 {
543 	struct imsgev	*iev = d;
544 	dispatch_imsg(iev, ev, handlers, sizeof(handlers));
545 }
546 
547 static void
548 load_page_from_str(struct tab *tab, const char *page)
549 {
550 	erase_buffer(&tab->buffer);
551 	gemtext_initparser(&tab->buffer.page);
552 	if (!tab->buffer.page.parse(&tab->buffer.page, page, strlen(page)))
553 		die();
554 	if (!tab->buffer.page.free(&tab->buffer.page))
555 		die();
556 	ui_on_tab_refresh(tab);
557 	ui_on_tab_loaded(tab);
558 }
559 
560 void
561 load_about_url(struct tab *tab, const char *url)
562 {
563 	tab->trust = TS_VERIFIED;
564 
565 	gemtext_initparser(&tab->buffer.page);
566 
567 	ui_send_fs(IMSG_GET, tab->id,
568 	    tab->hist_cur->h, strlen(tab->hist_cur->h)+1);
569 }
570 
571 void
572 load_gemini_url(struct tab *tab, const char *url)
573 {
574 	struct get_req	 req;
575 
576 	stop_tab(tab);
577 	tab->id = tab_new_id();
578 
579 	memset(&req, 0, sizeof(req));
580 	strlcpy(req.host, tab->uri.host, sizeof(req.host));
581 	strlcpy(req.port, tab->uri.port, sizeof(req.host));
582 
583 	strlcpy(req.req, tab->hist_cur->h, sizeof(req.req));
584 	strlcat(req.req, "\r\n", sizeof(req.req));
585 
586 	req.proto = PROTO_GEMINI;
587 
588 	ui_send_net(IMSG_GET_RAW, tab->id,
589 	    &req, sizeof(req));
590 }
591 
592 void
593 load_via_proxy(struct tab *tab, const char *url, struct proxy *p)
594 {
595 	struct get_req req;
596 
597 	stop_tab(tab);
598 	tab->id = tab_new_id();
599 	tab->proxy = p;
600 
601 	memset(&req, 0, sizeof(req));
602 	strlcpy(req.host, p->host, sizeof(req.host));
603 	strlcpy(req.port, p->port, sizeof(req.host));
604 
605 	strlcpy(req.req, tab->hist_cur->h, sizeof(req.req));
606 	strlcat(req.req, "\r\n", sizeof(req.req));
607 
608 	req.proto = p->proto;
609 
610 	ui_send_net(IMSG_GET_RAW, tab->id,
611 	    &req, sizeof(req));
612 }
613 
614 /*
615  * Effectively load the given url in the given tab.  Return 1 when
616  * loading the page asynchronously, and thus when an erase_buffer can
617  * be done right after this function return, or 0 when loading the
618  * page synchronously.  In this last case, erase_buffer *MUST* be
619  * called by the handling function (such as load_page_from_str).
620  */
621 static int
622 do_load_url(struct tab *tab, const char *url)
623 {
624 	struct phos_uri	 uri;
625 	struct proto	*p;
626 	struct proxy	*proxy;
627 	char		*t;
628 
629 	tab->proxy = NULL;
630 
631 	if (tab->fd != -1) {
632 		close(tab->fd);
633 		tab->fd = -1;
634 		free(tab->path);
635 		tab->path = NULL;
636 	}
637 
638 	tab->trust = TS_UNKNOWN;
639 
640 	memcpy(&uri, &tab->uri, sizeof(tab->uri));
641 	if (!phos_resolve_uri_from_str(&uri, url, &tab->uri)) {
642                 if (asprintf(&t, "#error loading %s\n>%s\n",
643 		    url, "Can't parse the URI") == -1)
644 			die();
645 		strlcpy(tab->hist_cur->h, url, sizeof(tab->hist_cur->h));
646 		load_page_from_str(tab, t);
647 		free(t);
648 		return 0;
649 	}
650 
651 	phos_serialize_uri(&tab->uri, tab->hist_cur->h,
652 	    sizeof(tab->hist_cur->h));
653 
654 	for (p = protos; p->schema != NULL; ++p) {
655 		if (!strcmp(tab->uri.scheme, p->schema)) {
656 			p->loadfn(tab, url);
657                         return 1;
658 		}
659 	}
660 
661 	TAILQ_FOREACH(proxy, &proxies, proxies) {
662 		if (!strcmp(tab->uri.scheme, proxy->match_proto)) {
663 			load_via_proxy(tab, url, proxy);
664 			return 1;
665 		}
666 	}
667 
668 	load_page_from_str(tab, err_pages[UNKNOWN_PROTOCOL]);
669 	return 0;
670 }
671 
672 /*
673  * Load url in tab.  If tab is marked as lazy, only prepare the url
674  * but don't load it.  If tab is lazy and a url was already prepared,
675  * do load it!
676  */
677 void
678 load_url(struct tab *tab, const char *url)
679 {
680 	int lazy;
681 
682 	lazy = tab->flags & TAB_LAZY;
683 
684 	if (lazy && tab->hist_cur != NULL) {
685 		lazy = 0;
686 		tab->flags &= ~TAB_LAZY;
687 	}
688 
689 	if (!lazy || tab->hist_cur == NULL) {
690 		if (tab->hist_cur != NULL)
691 			hist_clear_forward(&tab->hist,
692 			    TAILQ_NEXT(tab->hist_cur, entries));
693 
694 		if ((tab->hist_cur = calloc(1, sizeof(*tab->hist_cur))) == NULL) {
695 			event_loopbreak();
696 			return;
697 		}
698 
699 		strlcpy(tab->buffer.page.title, url,
700 		    sizeof(tab->buffer.page.title));
701 		hist_push(&tab->hist, tab->hist_cur);
702 
703 		if (lazy)
704 			strlcpy(tab->hist_cur->h, url,
705 			    sizeof(tab->hist_cur->h));
706 	}
707 
708 	if (!lazy && do_load_url(tab, url))
709 		erase_buffer(&tab->buffer);
710 }
711 
712 int
713 load_previous_page(struct tab *tab)
714 {
715 	struct hist	*h;
716 
717 	if ((h = TAILQ_PREV(tab->hist_cur, mhisthead, entries)) == NULL)
718 		return 0;
719 	tab->hist_cur = h;
720 	do_load_url(tab, h->h);
721 	return 1;
722 }
723 
724 int
725 load_next_page(struct tab *tab)
726 {
727 	struct hist	*h;
728 
729 	if ((h = TAILQ_NEXT(tab->hist_cur, entries)) == NULL)
730 		return 0;
731 	tab->hist_cur = h;
732 	do_load_url(tab, h->h);
733 	return 1;
734 }
735 
736 void
737 stop_tab(struct tab *tab)
738 {
739 	ui_send_net(IMSG_STOP, tab->id, NULL, 0);
740 
741 	if (tab->fd != -1) {
742 		close(tab->fd);
743 		tab->fd = -1;
744 		free(tab->path);
745 		tab->path = NULL;
746 		load_page_from_str(tab, "Stopped.\n");
747 	}
748 }
749 
750 void
751 add_to_bookmarks(const char *str)
752 {
753 	ui_send_fs(IMSG_BOOKMARK_PAGE, 0,
754 	    str, strlen(str)+1);
755 }
756 
757 void
758 save_session(void)
759 {
760 	struct tab	*tab;
761 	char		*t;
762 	int		 flags;
763 
764 	ui_send_fs(IMSG_SESSION_START, 0, NULL, 0);
765 
766 	TAILQ_FOREACH(tab, &tabshead, tabs) {
767 		flags = tab->flags;
768 		if (tab == current_tab)
769 			flags |= TAB_CURRENT;
770 
771 		t = tab->hist_cur->h;
772 		ui_send_fs(IMSG_SESSION_TAB, flags, t, strlen(t)+1);
773 
774 		t = tab->buffer.page.title;
775 		ui_send_fs(IMSG_SESSION_TAB_TITLE, 0, t, strlen(t)+1);
776 	}
777 
778 	ui_send_fs(IMSG_SESSION_END, 0, NULL, 0);
779 }
780 
781 /*
782  * Parse a line of the session file.  The format is:
783  *
784  *	URL [flags,...] [title]\n
785  */
786 static void
787 parse_session_line(char *line, const char **title, uint32_t *flags)
788 {
789 	char *s, *t, *ap;
790 
791 	*title = "";
792 	*flags = 0;
793 	if ((s = strchr(line, ' ')) == NULL)
794 		return;
795 
796 	*s++ = '\0';
797 
798         if ((t = strchr(s, ' ')) != NULL) {
799 		*t++ = '\0';
800 		*title = t;
801 	}
802 
803 	while ((ap = strsep(&s, ",")) != NULL) {
804 		if (*ap == '\0')
805 			;
806 		else if (!strcmp(ap, "current"))
807 			*flags |= TAB_CURRENT;
808 		else
809 			message("unknown tab flag: %s", ap);
810 	}
811 }
812 
813 static void
814 load_last_session(void)
815 {
816 	const char	*title;
817 	char		*nl, *line = NULL;
818 	uint32_t	 flags;
819 	size_t		 linesize = 0;
820 	ssize_t		 linelen;
821 	FILE		*session;
822 	struct tab	*tab, *curr = NULL;
823 
824 	if ((session = fopen(session_file, "r")) == NULL) {
825 		/* first time? */
826 		new_tab("about:new");
827 		switch_to_tab(new_tab("about:help"));
828 		return;
829 	}
830 
831 	while ((linelen = getline(&line, &linesize, session)) != -1) {
832                 if ((nl = strchr(line, '\n')) != NULL)
833 			*nl = '\0';
834 		parse_session_line(line, &title, &flags);
835 		if ((tab = new_tab(line)) == NULL)
836 			err(1, "new_tab");
837                 strlcpy(tab->buffer.page.title, title,
838 		    sizeof(tab->buffer.page.title));
839 		if (flags & TAB_CURRENT)
840 			curr = tab;
841 	}
842 
843 	if (ferror(session))
844 		message("error reading %s: %s",
845 		    session_file, strerror(errno));
846 	fclose(session);
847 	free(line);
848 
849 	if (curr != NULL)
850 		switch_to_tab(curr);
851 
852 	return;
853 }
854 
855 static pid_t
856 start_child(enum telescope_process p, const char *argv0, int fd)
857 {
858 	const char	*argv[4];
859 	int		 argc = 0;
860 	pid_t		 pid;
861 
862 	switch (pid = fork()) {
863 	case -1:
864 		die();
865 	case 0:
866 		break;
867 	default:
868 		close(fd);
869 		return pid;
870 	}
871 
872 	if (dup2(fd, 3) == -1)
873 		err(1, "cannot setup imsg fd");
874 
875 	argv[argc++] = argv0;
876 	switch (p) {
877 	case PROC_UI:
878 		errx(1, "Can't start ui process");
879 	case PROC_FS:
880 		argv[argc++] = "-Tf";
881 		break;
882 	case PROC_NET:
883 		argv[argc++] = "-Tn";
884 		break;
885 	}
886 
887 	argv[argc++] = NULL;
888 	execvp(argv0, (char *const *)argv);
889 	err(1, "execvp(%s)", argv0);
890 }
891 
892 static int
893 ui_send_net(int type, uint32_t peerid, const void *data,
894     uint16_t datalen)
895 {
896 	return imsg_compose_event(iev_net, type, peerid, 0, -1, data,
897 	    datalen);
898 }
899 
900 static int
901 ui_send_fs(int type, uint32_t peerid, const void *data, uint16_t datalen)
902 {
903 	return imsg_compose_event(iev_fs, type, peerid, 0, -1, data,
904 	    datalen);
905 }
906 
907 static void __attribute__((noreturn))
908 usage(int r)
909 {
910 	fprintf(stderr, "USAGE: %s [-hnv] [-c config] [url]\n",
911 	    getprogname());
912 	fprintf(stderr, "version: " PACKAGE " " VERSION "\n");
913 	exit(r);
914 }
915 
916 int
917 main(int argc, char * const *argv)
918 {
919 	struct imsgev	 net_ibuf, fs_ibuf;
920 	int		 pipe2net[2], pipe2fs[2];
921 	int		 ch, configtest = 0, fail = 0;
922 	int		 has_url = 0;
923 	int		 proc = -1;
924 	int		 sessionfd;
925 	char		 path[PATH_MAX];
926 	const char	*url = NEW_TAB_URL;
927 	const char	*argv0;
928 
929 	argv0 = argv[0];
930 
931 	signal(SIGCHLD, SIG_IGN);
932 	signal(SIGPIPE, SIG_IGN);
933 
934 	if (getenv("NO_COLOR") != NULL)
935 		enable_colors = 0;
936 
937 	strlcpy(path, getenv("HOME"), sizeof(path));
938 	strlcat(path, "/.telescope/config", sizeof(path));
939 
940 	while ((ch = getopt_long(argc, argv, opts, longopts, NULL)) != -1) {
941 		switch (ch) {
942 		case 'C':
943 			exit(ui_print_colors());
944 		case 'c':
945 			fail = 1;
946 			strlcpy(path, optarg, sizeof(path));
947 			break;
948 		case 'n':
949 			configtest = 1;
950 			break;
951 		case 'h':
952 			usage(0);
953 		case 'T':
954 			switch (*optarg) {
955 			case 'f':
956 				proc = PROC_FS;
957 				break;
958 			case 'n':
959 				proc = PROC_NET;
960 				break;
961 			default:
962 				errx(1, "invalid process spec %c",
963 				    *optarg);
964 			}
965 			break;
966 		case 'v':
967 			printf("%s %s\n", PACKAGE_NAME, PACKAGE_VERSION);
968 			exit(0);
969 			break;
970 		default:
971 			usage(1);
972 		}
973 	}
974 
975 	argc -= optind;
976 	argv += optind;
977 
978 	if (proc != -1) {
979 		if (argc > 0)
980 			usage(1);
981 		else if (proc == PROC_FS)
982 			return fs_main();
983 		else if (proc == PROC_NET)
984 			return client_main();
985 		else
986 			usage(1);
987 	}
988 
989 	if (argc != 0) {
990 		has_url = 1;
991 		url = argv[0];
992 	}
993 
994 	/* setup keys before reading the config */
995 	TAILQ_INIT(&global_map.m);
996 	global_map.unhandled_input = global_key_unbound;
997 	TAILQ_INIT(&minibuffer_map.m);
998 
999 	config_init();
1000 	parseconfig(path, fail);
1001 	if (configtest){
1002 		puts("config OK");
1003 		exit(0);
1004 	}
1005 
1006 	fs_init();
1007 	if ((sessionfd = lock_session()) == -1)
1008 		errx(1, "can't lock session, is another instance of "
1009 		    "telescope already running?");
1010 
1011 	/* Start children. */
1012 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pipe2fs) == -1)
1013 		err(1, "socketpair");
1014 	start_child(PROC_FS, argv0, pipe2fs[1]);
1015 	imsg_init(&fs_ibuf.ibuf, pipe2fs[0]);
1016 	iev_fs = &fs_ibuf;
1017 	iev_fs->handler = handle_dispatch_imsg;
1018 
1019 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pipe2net) == -1)
1020 		err(1, "socketpair");
1021 	start_child(PROC_NET, argv0, pipe2net[1]);
1022 	imsg_init(&net_ibuf.ibuf, pipe2net[0]);
1023 	iev_net = &net_ibuf;
1024 	iev_net->handler = handle_dispatch_imsg;
1025 
1026 	setproctitle("ui");
1027 
1028 	/* initialize tofu & load certificates */
1029 	tofu_init(&certs, 5, offsetof(struct tofu_entry, domain));
1030 	load_certs(&certs);
1031 
1032 	event_init();
1033 
1034 	/* Setup event handlers for pipes to fs/net */
1035 	iev_fs->events = EV_READ;
1036 	event_set(&iev_fs->ev, iev_fs->ibuf.fd, iev_fs->events,
1037 	    iev_fs->handler, iev_fs);
1038 	event_add(&iev_fs->ev, NULL);
1039 
1040 	iev_net->events = EV_READ;
1041 	event_set(&iev_net->ev, iev_net->ibuf.fd, iev_net->events,
1042 	    iev_net->handler, iev_net);
1043 	event_add(&iev_net->ev, NULL);
1044 
1045 	if (ui_init()) {
1046 		load_last_session();
1047 		if (has_url || TAILQ_EMPTY(&tabshead))
1048 			new_tab(url);
1049 
1050 		sandbox_ui_process();
1051 		ui_main_loop();
1052 		ui_end();
1053 	}
1054 
1055 	ui_send_fs(IMSG_QUIT, 0, NULL, 0);
1056 	ui_send_net(IMSG_QUIT, 0, NULL, 0);
1057 	imsg_flush(&iev_fs->ibuf);
1058 	imsg_flush(&iev_net->ibuf);
1059 
1060 	close(sessionfd);
1061 
1062 	return 0;
1063 }