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