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 /*
18  * Handles config and runtime files
19  */
20 
21 #include "compat.h"
22 
23 #include <sys/stat.h>
24 #include <sys/types.h>
25 
26 #include <dirent.h>
27 #include <errno.h>
28 #include <fcntl.h>
29 #include <limits.h>
30 #include <libgen.h>
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <string.h>
34 #include <unistd.h>
35 
36 #include "fs.h"
37 #include "pages.h"
38 #include "telescope.h"
39 #include "session.h"
40 
41 static void		 die(void) __attribute__((__noreturn__));
42 static void		 send_file(uint32_t, FILE *);
43 static void		 handle_get(struct imsg*, size_t);
44 static int		 select_non_dot(const struct dirent *);
45 static int		 select_non_dotdot(const struct dirent *);
46 static void		 handle_get_file(struct imsg*, size_t);
47 static void		 handle_misc(struct imsg *, size_t);
48 static void		 handle_bookmark_page(struct imsg*, size_t);
49 static void		 handle_save_cert(struct imsg*, size_t);
50 static void		 handle_update_cert(struct imsg*, size_t);
51 static void		 handle_file_open(struct imsg*, size_t);
52 static void		 handle_session_start(struct imsg*, size_t);
53 static void		 handle_session_tab(struct imsg*, size_t);
54 static void		 handle_session_tab_hist(struct imsg*, size_t);
55 static void		 handle_session_end(struct imsg*, size_t);
56 static void		 handle_dispatch_imsg(int, short, void*);
57 static int		 fs_send_ui(int, uint32_t, int, const void *, uint16_t);
58 static size_t		 join_path(char*, const char*, const char*, size_t);
59 static void		 getenv_default(char*, const char*, const char*, size_t);
60 static void		 mkdirs(const char*, mode_t);
61 static void		 init_paths(void);
62 static void		 load_last_session(void);
63 static int		 last_time_crashed(void);
64 static void		 load_certs(void);
65 
66 static struct imsgev		*iev_ui;
67 static FILE			*session;
68 
69 /*
70  * Where to store user data.  These are all equal to ~/.telescope if
71  * it exists.
72  */
73 char		config_path_base[PATH_MAX];
74 char		data_path_base[PATH_MAX];
75 char		cache_path_base[PATH_MAX];
76 
77 char		config_path[PATH_MAX];
78 char		lockfile_path[PATH_MAX];
79 char		bookmark_file[PATH_MAX];
80 char		known_hosts_file[PATH_MAX], known_hosts_tmp[PATH_MAX];
81 char		crashed_file[PATH_MAX];
82 char		session_file[PATH_MAX];
83 
84 static imsg_handlerfn *handlers[] = {
85 	[IMSG_GET] = handle_get,
86 	[IMSG_GET_FILE] = handle_get_file,
87 	[IMSG_QUIT] = handle_misc,
88 	[IMSG_INIT] = handle_misc,
89 	[IMSG_BOOKMARK_PAGE] = handle_bookmark_page,
90 	[IMSG_SAVE_CERT] = handle_save_cert,
91 	[IMSG_UPDATE_CERT] = handle_update_cert,
92 	[IMSG_FILE_OPEN] = handle_file_open,
93 	[IMSG_SESSION_START] = handle_session_start,
94 	[IMSG_SESSION_TAB] = handle_session_tab,
95 	[IMSG_SESSION_TAB_HIST] = handle_session_tab_hist,
96 	[IMSG_SESSION_END] = handle_session_end,
97 };
98 
99 static void __attribute__((__noreturn__))
100 die(void)
101 {
102 	abort(); 		/* TODO */
103 }
104 
105 static void
106 send_file(uint32_t peerid, FILE *f)
107 {
108 	ssize_t	 r;
109 	char	 buf[BUFSIZ];
110 
111 	for (;;) {
112 		r = fread(buf, 1, sizeof(buf), f);
113 		if (r != 0)
114 			fs_send_ui(IMSG_BUF, peerid, -1, buf, r);
115 		if (r != sizeof(buf))
116 			break;
117 	}
118 	fs_send_ui(IMSG_EOF, peerid, -1, NULL, 0);
119 	fclose(f);
120 }
121 
122 static void
123 handle_get(struct imsg *imsg, size_t datalen)
124 {
125 	const char	*bpath = "bookmarks.gmi";
126 	char		 path[PATH_MAX];
127 	FILE		*f;
128 	const char	*data, *p;
129 	size_t		 i;
130 	struct page {
131 		const char	*name;
132 		const char	*path;
133 		const uint8_t	*data;
134 		size_t		 len;
135 	} pages[] = {
136 		{"about",	NULL,	about_about,	about_about_len},
137 		{"blank",	NULL,	about_blank,	about_blank_len},
138 		{"bookmarks",	bpath,	bookmarks,	bookmarks_len},
139 		{"crash",	NULL,	about_crash,	about_crash_len},
140 		{"help",	NULL,	about_help,	about_help_len},
141 		{"license",	NULL,	about_license,	about_license_len},
142 		{"new",		NULL,	about_new,	about_new_len},
143 	}, *page = NULL;
144 
145 	data = imsg->data;
146 	if (data[datalen-1] != '\0') /* make sure it's NUL-terminated */
147 		die();
148 	if ((data = strchr(data, ':')) == NULL)
149 		goto notfound;
150 	data++;
151 
152 	for (i = 0; i < sizeof(pages)/sizeof(pages[0]); ++i)
153 		if (!strcmp(data, pages[i].name)) {
154 			page = &pages[i];
155 			break;
156 		}
157 
158 	if (page == NULL)
159 		goto notfound;
160 
161 	strlcpy(path, data_path_base, sizeof(path));
162 	strlcat(path, "/", sizeof(path));
163 	if (page->path != NULL)
164 		strlcat(path, page->path, sizeof(path));
165 	else {
166 		strlcat(path, "pages/about_", sizeof(path));
167 		strlcat(path, page->name, sizeof(path));
168 		strlcat(path, ".gmi", sizeof(path));
169 	}
170 
171 	if ((f = fopen(path, "r")) == NULL) {
172 		fs_send_ui(IMSG_BUF, imsg->hdr.peerid, -1,
173 		    page->data, page->len);
174 		fs_send_ui(IMSG_EOF, imsg->hdr.peerid, -1,
175 		    NULL, 0);
176 		return;
177 	}
178 
179 	send_file(imsg->hdr.peerid, f);
180 	return;
181 
182 notfound:
183 	p = "# not found!\n";
184 	fs_send_ui(IMSG_BUF, imsg->hdr.peerid, -1, p, strlen(p));
185 	fs_send_ui(IMSG_EOF, imsg->hdr.peerid, -1, NULL, 0);
186 }
187 
188 static inline void
189 send_hdr(uint32_t peerid, int code, const char *meta)
190 {
191 	fs_send_ui(IMSG_GOT_CODE, peerid, -1, &code, sizeof(code));
192 	fs_send_ui(IMSG_GOT_META, peerid, -1, meta, strlen(meta)+1);
193 }
194 
195 static inline void
196 send_errno(uint32_t peerid, int code, const char *str, int no)
197 {
198 	char *s;
199 
200 	if (asprintf(&s, "%s: %s", str, strerror(no)) == -1)
201 		s = NULL;
202 
203 	send_hdr(peerid, code, s == NULL ? str : s);
204 	free(s);
205 }
206 
207 static inline const char *
208 file_type(const char *path)
209 {
210 	struct mapping {
211 		const char	*ext;
212 		const char	*mime;
213 	} ms[] = {
214 		{"diff",	"text/x-patch"},
215 		{"gemini",	"text/gemini"},
216 		{"gmi",		"text/gemini"},
217 		{"markdown",	"text/plain"},
218 		{"md",		"text/plain"},
219 		{"patch",	"text/x-patch"},
220 		{"txt",		"text/plain"},
221 		{NULL, NULL},
222 	}, *m;
223 	char *dot;
224 
225 	if ((dot = strrchr(path, '.')) == NULL)
226 		return NULL;
227 
228 	dot++;
229 
230 	for (m = ms; m->ext != NULL; ++m)
231 		if (!strcmp(m->ext, dot))
232 			return m->mime;
233 
234 	return NULL;
235 }
236 
237 static int
238 select_non_dot(const struct dirent *d)
239 {
240 	return strcmp(d->d_name, ".");
241 }
242 
243 static int
244 select_non_dotdot(const struct dirent *d)
245 {
246 	return strcmp(d->d_name, ".") && strcmp(d->d_name, "..");
247 }
248 
249 static inline void
250 send_dir(uint32_t peerid, const char *path)
251 {
252 	struct dirent	**names;
253 	struct evbuffer	 *ev;
254 	char		 *s;
255 	int		(*selector)(const struct dirent *) = select_non_dot;
256 	int		  i, len, no;
257 
258 	if (!has_suffix(path, "/")) {
259 		if (asprintf(&s, "%s/", path) == -1)
260 			die();
261 		send_hdr(peerid, 30, s);
262 		free(s);
263 		return;
264 	}
265 
266 	if (!strcmp(path, "/"))
267 		selector = select_non_dotdot;
268 
269 	if ((ev = evbuffer_new()) == NULL ||
270 	    (len = scandir(path, &names, selector, alphasort)) == -1) {
271 		no = errno;
272 		evbuffer_free(ev);
273 		send_errno(peerid, 40, "failure reading the directory", no);
274 		return;
275 	}
276 
277 	evbuffer_add_printf(ev, "# Index of %s\n\n", path);
278 	for (i = 0; i < len; ++i) {
279 		evbuffer_add_printf(ev, "=> %s", names[i]->d_name);
280 		if (names[i]->d_type == DT_DIR)
281 			evbuffer_add(ev, "/", 1);
282 		evbuffer_add(ev, "\n", 1);
283 	}
284 
285 	send_hdr(peerid, 20, "text/gemini");
286 	fs_send_ui(IMSG_BUF, peerid, -1,
287 	    EVBUFFER_DATA(ev), EVBUFFER_LENGTH(ev));
288 	fs_send_ui(IMSG_EOF, peerid, -1, NULL, 0);
289 
290 	evbuffer_free(ev);
291 	free(names);
292 }
293 
294 static void
295 handle_get_file(struct imsg *imsg, size_t datalen)
296 {
297 	struct stat	 sb;
298 	FILE		*f;
299 	char		*data;
300 	const char	*meta = NULL;
301 
302 	data = imsg->data;
303 	data[datalen-1] = '\0';
304 
305 	if ((f = fopen(data, "r")) == NULL) {
306 		send_errno(imsg->hdr.peerid, 51, "can't open", errno);
307 		return;
308 	}
309 
310 	if (fstat(fileno(f), &sb) == -1) {
311 		send_errno(imsg->hdr.peerid, 40, "fstat", errno);
312 		return;
313 	}
314 
315 	if (S_ISDIR(sb.st_mode)) {
316 		fclose(f);
317 		send_dir(imsg->hdr.peerid, data);
318 		return;
319 	}
320 
321 	if ((meta = file_type(data)) == NULL) {
322 		fclose(f);
323 		send_hdr(imsg->hdr.peerid, 51,
324 		    "don't know how to visualize this file");
325 		return;
326 	}
327 
328 	send_hdr(imsg->hdr.peerid, 20, meta);
329 	send_file(imsg->hdr.peerid, f);
330 }
331 
332 static void
333 handle_misc(struct imsg *imsg, size_t datalen)
334 {
335 	switch (imsg->hdr.type) {
336 	case IMSG_INIT:
337 		load_certs();
338 		load_last_session();
339 		break;
340 
341 	case IMSG_QUIT:
342 		if (!safe_mode)
343 			unlink(crashed_file);
344 		event_loopbreak();
345 		break;
346 
347 	default:
348 		die();
349 	}
350 }
351 
352 static void
353 handle_bookmark_page(struct imsg *imsg, size_t datalen)
354 {
355 	char	*data;
356 	int	 res;
357 	FILE	*f;
358 
359 	data = imsg->data;
360 	if (data[datalen-1] != '\0')
361 		die();
362 
363 	if ((f = fopen(bookmark_file, "a")) == NULL) {
364 		res = errno;
365 		goto end;
366 	}
367 	fprintf(f, "=> %s\n", data);
368 	fclose(f);
369 
370 	res = 0;
371 end:
372 	fs_send_ui(IMSG_BOOKMARK_OK, 0, -1, &res, sizeof(res));
373 }
374 
375 static void
376 handle_save_cert(struct imsg *imsg, size_t datalen)
377 {
378 	struct tofu_entry	 e;
379 	FILE			*f;
380 	int			 res;
381 
382 	/* TODO: traverse the file to avoid duplications? */
383 
384 	if (datalen != sizeof(e))
385 		die();
386 	memcpy(&e, imsg->data, datalen);
387 
388 	if ((f = fopen(known_hosts_file, "a")) == NULL) {
389 		res = errno;
390 		goto end;
391 	}
392 	fprintf(f, "%s %s %d\n", e.domain, e.hash, e.verified);
393 	fclose(f);
394 
395 	res = 0;
396 end:
397 	fs_send_ui(IMSG_SAVE_CERT_OK, imsg->hdr.peerid, -1,
398 	    &res, sizeof(res));
399 }
400 
401 static void
402 handle_update_cert(struct imsg *imsg, size_t datalen)
403 {
404 	FILE	*tmp, *f;
405 	struct	 tofu_entry entry;
406 	char	 sfn[PATH_MAX], *line = NULL, *t;
407 	size_t	 l, linesize = 0;
408 	ssize_t	 linelen;
409 	int	 fd, e, res = 0;
410 
411 	if (datalen != sizeof(entry))
412 		die();
413 	memcpy(&entry, imsg->data, datalen);
414 
415 	strlcpy(sfn, known_hosts_tmp, sizeof(sfn));
416 	if ((fd = mkstemp(sfn)) == -1 ||
417 	    (tmp = fdopen(fd, "w")) == NULL) {
418 		if (fd != -1) {
419 			unlink(sfn);
420 			close(fd);
421 		}
422 		res = 0;
423 		goto end;
424 	}
425 
426 	if ((f = fopen(known_hosts_file, "r")) == NULL) {
427 		unlink(sfn);
428 		fclose(tmp);
429                 res = 0;
430 		goto end;
431 	}
432 
433 	l = strlen(entry.domain);
434 	while ((linelen = getline(&line, &linesize, f)) != -1) {
435 		if ((t = strstr(line, entry.domain)) != NULL &&
436 		    (line[l] == ' ' || line[l] == '\t'))
437 			continue;
438 		/* line has a trailing \n */
439 		fprintf(tmp, "%s", line);
440 	}
441 	fprintf(tmp, "%s %s %d\n", entry.domain, entry.hash, entry.verified);
442 
443 	free(line);
444 	e = ferror(tmp);
445 
446 	fclose(tmp);
447 	fclose(f);
448 
449 	if (e) {
450 		unlink(sfn);
451 		res = 0;
452 		goto end;
453 	}
454 
455 	res = rename(sfn, known_hosts_file) != -1;
456 
457 end:
458 	fs_send_ui(IMSG_UPDATE_CERT_OK, imsg->hdr.peerid, -1,
459 	    &res, sizeof(res));
460 }
461 
462 static void
463 handle_file_open(struct imsg *imsg, size_t datalen)
464 {
465 	char	*path, *e;
466 	int	 fd;
467 
468 	path = imsg->data;
469 	if (path[datalen-1] != '\0')
470 		die();
471 
472 	if ((fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, 0644)) == -1) {
473 		e = strerror(errno);
474 		fs_send_ui(IMSG_FILE_OPENED, imsg->hdr.peerid, -1,
475 		    e, strlen(e)+1);
476 	} else
477 		fs_send_ui(IMSG_FILE_OPENED, imsg->hdr.peerid, fd,
478 		    NULL, 0);
479 }
480 
481 static void
482 handle_session_start(struct imsg *imsg, size_t datalen)
483 {
484 	if (datalen != 0)
485 		die();
486 
487 	if ((session = fopen(session_file, "w")) == NULL)
488 		die();
489 }
490 
491 static void
492 handle_session_tab(struct imsg *imsg, size_t datalen)
493 {
494 	struct session_tab	tab;
495 
496 	if (session == NULL)
497 		die();
498 
499 	if (datalen != sizeof(tab))
500 		die();
501 
502 	memcpy(&tab, imsg->data, sizeof(tab));
503 	if (tab.uri[sizeof(tab.uri)-1] != '\0' ||
504 	    tab.title[sizeof(tab.title)-1] != '\0')
505 		die();
506 
507 	fprintf(session, "%s", tab.uri);
508 
509 	if (tab.flags == 0)
510 		fprintf(session, " - ");
511 	else {
512 		fprintf(session, " ");
513 		if (tab.flags & TAB_CURRENT)
514 			fprintf(session, "current,");
515 		if (tab.flags & TAB_KILLED)
516 			fprintf(session, "killed,");
517 		fprintf(session, " ");
518 	}
519 
520 	fprintf(session, "%s\n", tab.title);
521 }
522 
523 static void
524 handle_session_tab_hist(struct imsg *imsg, size_t datalen)
525 {
526 	struct session_tab_hist th;
527 
528 	if (session == NULL)
529 		die();
530 
531 	if (datalen != sizeof(th))
532 		die();
533 
534 	memcpy(&th, imsg->data, sizeof(th));
535 	if (th.uri[sizeof(th.uri)-1] != '\0')
536 		die();
537 
538 	fprintf(session, "%s %s\n", th.future ? ">" : "<", th.uri);
539 }
540 
541 static void
542 handle_session_end(struct imsg *imsg, size_t datalen)
543 {
544 	if (session == NULL)
545 		die();
546 	fclose(session);
547 	session = NULL;
548 }
549 
550 static void
551 handle_dispatch_imsg(int fd, short ev, void *d)
552 {
553 	struct imsgev	*iev = d;
554 	int		 e;
555 
556 	if (dispatch_imsg(iev, ev, handlers, sizeof(handlers)) == -1) {
557 		/*
558 		 * This should leave a ~/.cache/telescope/crashed file to
559 		 * trigger about:crash on next run.  Unfortunately, if
560 		 * the main process dies the fs sticks around and
561 		 * doesn't notice that the fd was closed.  Why EV_READ
562 		 * is not triggered when a fd is closed on the other end?
563 		 */
564 		e = errno;
565 		if ((fd = open(crashed_file, O_CREAT|O_TRUNC|O_WRONLY, 0600))
566 		    == -1)
567 			err(1, "open");
568 		close(fd);
569 		errx(1, "connection closed: %s", strerror(e));
570 	}
571 }
572 
573 static int
574 fs_send_ui(int type, uint32_t peerid, int fd, const void *data,
575     uint16_t datalen)
576 {
577 	return imsg_compose_event(iev_ui, type, peerid, 0, fd,
578 	    data, datalen);
579 }
580 
581 static size_t
582 join_path(char *buf, const char *lhs, const char *rhs, size_t buflen)
583 {
584 	strlcpy(buf, lhs, buflen);
585 	return strlcat(buf, rhs, buflen);
586 }
587 
588 static void
589 getenv_default(char *buf, const char *name, const char *def, size_t buflen)
590 {
591 	size_t ret;
592 	char *home, *env;
593 
594 	if ((home = getenv("HOME")) == NULL)
595 		errx(1, "HOME is not defined");
596 
597 	if ((env = getenv(name)) != NULL)
598 		ret = strlcpy(buf, env, buflen);
599 	else
600 		ret = join_path(buf, home, def, buflen);
601 
602 	if (ret >= buflen)
603 		errx(1, "buffer too small for %s", name);
604 }
605 
606 static void
607 mkdirs(const char *path, mode_t mode)
608 {
609 	char copy[PATH_MAX+1], orig[PATH_MAX+1], *parent;
610 
611 	strlcpy(copy, path, sizeof(copy));
612 	strlcpy(orig, path, sizeof(orig));
613 	parent = dirname(copy);
614 	if (!strcmp(parent, "/"))
615 		return;
616 	mkdirs(parent, mode);
617 
618 	if (mkdir(orig, mode) != 0) {
619 		if (errno == EEXIST)
620 			return;
621 		err(1, "can't mkdir %s", orig);
622 	}
623 }
624 
625 static void
626 init_paths(void)
627 {
628 	char		 xdg_config_base[PATH_MAX];
629 	char		 xdg_data_base[PATH_MAX];
630 	char		 xdg_cache_base[PATH_MAX];
631 	char		 old_path[PATH_MAX];
632 	char		*home;
633 	struct stat	 info;
634 
635 	/* old path */
636 	if ((home = getenv("HOME")) == NULL)
637 		errx(1, "HOME is not defined");
638 	join_path(old_path, home, "/.telescope", sizeof(old_path));
639 
640 	/* if ~/.telescope exists, use that instead of xdg dirs */
641 	if (stat(old_path, &info) == 0 && S_ISDIR(info.st_mode)) {
642 		join_path(config_path_base, home, "/.telescope",
643 		    sizeof(config_path_base));
644 		join_path(data_path_base, home, "/.telescope",
645 		    sizeof(data_path_base));
646 		join_path(cache_path_base, home, "/.telescope",
647 		    sizeof(cache_path_base));
648 		return;
649 	}
650 
651 	/* xdg paths */
652 	getenv_default(xdg_config_base, "XDG_CONFIG_HOME", "/.config",
653 	    sizeof(xdg_config_base));
654 	getenv_default(xdg_data_base, "XDG_DATA_HOME", "/.local/share",
655 	    sizeof(xdg_data_base));
656 	getenv_default(xdg_cache_base, "XDG_CACHE_HOME", "/.cache",
657 	    sizeof(xdg_cache_base));
658 
659 	join_path(config_path_base, xdg_config_base, "/telescope",
660 	    sizeof(config_path_base));
661 	join_path(data_path_base, xdg_data_base, "/telescope",
662 	    sizeof(data_path_base));
663 	join_path(cache_path_base, xdg_cache_base, "/telescope",
664 	    sizeof(cache_path_base));
665 
666 	mkdirs(xdg_config_base, S_IRWXU);
667 	mkdirs(xdg_data_base, S_IRWXU);
668 	mkdirs(xdg_cache_base, S_IRWXU);
669 
670 	mkdirs(config_path_base, S_IRWXU);
671 	mkdirs(data_path_base, S_IRWXU);
672 	mkdirs(cache_path_base, S_IRWXU);
673 }
674 
675 int
676 fs_init(void)
677 {
678 	init_paths();
679 
680 	join_path(config_path, config_path_base, "/config",
681 	    sizeof(config_path));
682 	join_path(lockfile_path, cache_path_base, "/lock",
683 	    sizeof(lockfile_path));
684 	join_path(bookmark_file, data_path_base, "/bookmarks.gmi",
685 	    sizeof(bookmark_file));
686 	join_path(known_hosts_file, data_path_base, "/known_hosts",
687 	    sizeof(known_hosts_file));
688 	join_path(known_hosts_tmp, cache_path_base,
689 	    "/known_hosts.tmp.XXXXXXXXXX", sizeof(known_hosts_tmp));
690 	join_path(session_file, cache_path_base, "/session",
691 	    sizeof(session_file));
692 	join_path(crashed_file, cache_path_base, "/crashed",
693 	    sizeof(crashed_file));
694 
695 	return 1;
696 }
697 
698 /*
699  * Parse a line of the session file.  The format is:
700  *
701  *	URL [flags,...] [title]\n
702  */
703 static void
704 parse_session_line(char *line, const char **title, uint32_t *flags)
705 {
706 	char *s, *t, *ap;
707 
708 	*title = "";
709 	*flags = 0;
710 	if ((s = strchr(line, ' ')) == NULL)
711 		return;
712 
713 	*s++ = '\0';
714 
715 	if ((t = strchr(s, ' ')) != NULL) {
716 		*t++ = '\0';
717 		*title = t;
718 	}
719 
720 	while ((ap = strsep(&s, ",")) != NULL) {
721 		if (!strcmp(ap, "current"))
722 			*flags |= TAB_CURRENT;
723 		else if (!strcmp(ap, "killed"))
724 			*flags |= TAB_KILLED;
725 	}
726 }
727 
728 static inline void
729 sendtab(uint32_t flags, const char *uri, const char *title)
730 {
731 	struct session_tab tab;
732 
733 	memset(&tab, 0, sizeof(tab));
734 	tab.flags = flags;
735 
736 	if (strlcpy(tab.uri, uri, sizeof(tab.uri)) >= sizeof(tab.uri))
737 		return;
738 
739 	/* don't worry about cached title truncation */
740 	if (title != NULL)
741 		strlcpy(tab.title, title, sizeof(tab.title));
742 
743 	fs_send_ui(IMSG_SESSION_TAB, 0, -1, &tab, sizeof(tab));
744 }
745 
746 static inline void
747 sendhist(const char *uri, int future)
748 {
749 	struct session_tab_hist sth;
750 
751 	memset(&sth, 0, sizeof(sth));
752 	sth.future = future;
753 
754 	if (strlcpy(sth.uri, uri, sizeof(sth.uri)) >= sizeof(sth.uri))
755 		return;
756 
757 	fs_send_ui(IMSG_SESSION_TAB_HIST, 0, -1, &sth, sizeof(sth));
758 }
759 
760 static void
761 load_last_session(void)
762 {
763 	FILE		*session;
764 	uint32_t	 flags;
765 	size_t		 linesize = 0;
766 	ssize_t		 linelen;
767 	int		 first_time = 0;
768 	int		 future;
769 	const char	*title;
770 	char		*nl, *s, *line = NULL;
771 
772 	if ((session = fopen(session_file, "r")) == NULL) {
773 		/* first time? */
774 		first_time = 1;
775 		goto end;
776 	}
777 
778 	while ((linelen = getline(&line, &linesize, session)) != -1) {
779 		if ((nl = strchr(line, '\n')) != NULL)
780 			*nl = '\0';
781 
782 		if (*line == '<' || *line == '>') {
783 			future = *line == '>';
784 			s = line+1;
785 			if (*s != ' ')
786 				continue;
787 			sendhist(++s, future);
788 		} else {
789 			parse_session_line(line, &title, &flags);
790 			sendtab(flags, line, title);
791 		}
792 	}
793 
794 	fclose(session);
795 	free(line);
796 
797 	if (last_time_crashed())
798 		sendtab(TAB_CURRENT, "about:crash", NULL);
799 
800 end:
801 	fs_send_ui(IMSG_SESSION_END, 0, -1, &first_time, sizeof(first_time));
802 }
803 
804 int
805 fs_main(void)
806 {
807 	setproctitle("fs");
808 
809 	fs_init();
810 
811 	event_init();
812 
813 	/* Setup pipe and event handler to the main process */
814 	if ((iev_ui = malloc(sizeof(*iev_ui))) == NULL)
815 		die();
816 	imsg_init(&iev_ui->ibuf, 3);
817 	iev_ui->handler = handle_dispatch_imsg;
818 	iev_ui->events = EV_READ;
819 	event_set(&iev_ui->ev, iev_ui->ibuf.fd, iev_ui->events,
820 	    iev_ui->handler, iev_ui);
821 	event_add(&iev_ui->ev, NULL);
822 
823 	sandbox_fs_process();
824 
825 	event_dispatch();
826 	return 0;
827 }
828 
829 /*
830  * Check if the last time telescope crashed.  The check is done by
831  * looking at `crashed_file': if it exists then last time we crashed.
832  * Then, while here, touch the file too.  During IMSG_QUIT we'll
833  * remove it.
834  */
835 static int
836 last_time_crashed(void)
837 {
838 	int fd, crashed = 1;
839 
840 	if (safe_mode)
841 		return 0;
842 
843 	if (unlink(crashed_file) == -1 && errno == ENOENT)
844 		crashed = 0;
845 
846 	if ((fd = open(crashed_file, O_CREAT|O_WRONLY, 0600)) == -1)
847 		return crashed;
848 	close(fd);
849 
850 	return crashed;
851 }
852 
853 int
854 lock_session(void)
855 {
856 	struct flock	lock;
857 	int		fd;
858 
859 	if ((fd = open(lockfile_path, O_WRONLY|O_CREAT, 0600)) == -1)
860 		return -1;
861 
862 	lock.l_start = 0;
863 	lock.l_len = 0;
864 	lock.l_type = F_WRLCK;
865 	lock.l_whence = SEEK_SET;
866 
867 	if (fcntl(fd, F_SETLK, &lock) == -1) {
868 		close(fd);
869 		return -1;
870 	}
871 
872 	return fd;
873 }
874 
875 static inline int
876 parse_khost_line(char *line, char *tmp[3])
877 {
878 	char **ap;
879 
880 	for (ap = tmp; ap < &tmp[3] &&
881 	    (*ap = strsep(&line, " \t\n")) != NULL;) {
882 		if (**ap != '\0')
883 			ap++;
884 	}
885 
886 	return ap == &tmp[3] && *line == '\0';
887 }
888 
889 static void
890 load_certs(void)
891 {
892 	char		*tmp[3], *line = NULL;
893 	const char	*errstr;
894 	size_t		 lineno = 0, linesize = 0;
895 	ssize_t		 linelen;
896 	FILE		*f;
897 	struct tofu_entry e;
898 
899 	if ((f = fopen(known_hosts_file, "r")) == NULL)
900 		return;
901 
902 	while ((linelen = getline(&line, &linesize, f)) != -1) {
903 		lineno++;
904 
905 		memset(&e, 0, sizeof(e));
906 		if (parse_khost_line(line, tmp)) {
907 			strlcpy(e.domain, tmp[0], sizeof(e.domain));
908 			strlcpy(e.hash, tmp[1], sizeof(e.hash));
909 
910 			e.verified = strtonum(tmp[2], 0, 1, &errstr);
911 			if (errstr != NULL)
912 				errx(1, "%s:%zu verification for %s is %s: %s",
913 				    known_hosts_file, lineno,
914 				    e.domain, errstr, tmp[2]);
915 
916 			fs_send_ui(IMSG_TOFU, 0, -1, &e, sizeof(e));
917 		} else {
918 			warnx("%s:%zu invalid entry",
919 			    known_hosts_file, lineno);
920 		}
921 	}
922 
923 	free(line);
924 	fclose(f);
925 	return;
926 }
927