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Date:: Mon Jan 3 11:45:07 2022 UTC
Message:: avoid zero-timer hack by triggering session initialization with IMSG_INIT
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1 /*
2  * Copyright (c) 2021 Omar Polo <op@omarpolo.com>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 /*
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_misc(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 static void		 load_last_session(void);
62 
63 static struct imsgev		*iev_ui;
64 static FILE			*session;
65 
66 /*
67  * Note: these are empty if ~/.telescope exists, use *_path_base
68  * below.
69  */
70 static char	xdg_config_base[PATH_MAX];
71 static char	xdg_data_base[PATH_MAX];
72 static char	xdg_cache_base[PATH_MAX];
73 
74 /*
75  * Where to store user data.  These are all equal to ~/.telescope if
76  * it exists.
77  */
78 char		config_path_base[PATH_MAX];
79 char		data_path_base[PATH_MAX];
80 char		cache_path_base[PATH_MAX];
81 
82 char		config_path[PATH_MAX];
83 char		lockfile_path[PATH_MAX];
84 char		bookmark_file[PATH_MAX];
85 char		known_hosts_file[PATH_MAX], known_hosts_tmp[PATH_MAX];
86 char		crashed_file[PATH_MAX];
87 char		session_file[PATH_MAX];
88 
89 static imsg_handlerfn *handlers[] = {
90 	[IMSG_GET] = handle_get,
91 	[IMSG_GET_FILE] = handle_get_file,
92 	[IMSG_QUIT] = handle_misc,
93 	[IMSG_INIT] = handle_misc,
94 	[IMSG_BOOKMARK_PAGE] = handle_bookmark_page,
95 	[IMSG_SAVE_CERT] = handle_save_cert,
96 	[IMSG_UPDATE_CERT] = handle_update_cert,
97 	[IMSG_FILE_OPEN] = handle_file_open,
98 	[IMSG_SESSION_START] = handle_session_start,
99 	[IMSG_SESSION_TAB] = handle_session_tab,
100 	[IMSG_SESSION_TAB_HIST] = handle_session_tab_hist,
101 	[IMSG_SESSION_END] = handle_session_end,
102 };
103 
104 static void __attribute__((__noreturn__))
105 die(void)
106 {
107 	abort(); 		/* TODO */
108 }
109 
110 static void
111 send_file(uint32_t peerid, FILE *f)
112 {
113 	ssize_t	 r;
114 	char	 buf[BUFSIZ];
115 
116 	for (;;) {
117 		r = fread(buf, 1, sizeof(buf), f);
118 		if (r != 0)
119 			fs_send_ui(IMSG_BUF, peerid, -1, buf, r);
120 		if (r != sizeof(buf))
121 			break;
122 	}
123 	fs_send_ui(IMSG_EOF, peerid, -1, NULL, 0);
124 	fclose(f);
125 }
126 
127 static void
128 handle_get(struct imsg *imsg, size_t datalen)
129 {
130 	const char	*bpath = "bookmarks.gmi";
131 	char		 path[PATH_MAX];
132 	FILE		*f;
133 	const char	*data, *p;
134 	size_t		 i;
135 	struct page {
136 		const char	*name;
137 		const char	*path;
138 		const uint8_t	*data;
139 		size_t		 len;
140 	} pages[] = {
141 		{"about",	NULL,	about_about,	about_about_len},
142 		{"blank",	NULL,	about_blank,	about_blank_len},
143 		{"bookmarks",	bpath,	bookmarks,	bookmarks_len},
144 		{"crash",	NULL,	about_crash,	about_crash_len},
145 		{"help",	NULL,	about_help,	about_help_len},
146 		{"license",	NULL,	about_license,	about_license_len},
147 		{"new",		NULL,	about_new,	about_new_len},
148 	}, *page = NULL;
149 
150 	data = imsg->data;
151 	if (data[datalen-1] != '\0') /* make sure it's NUL-terminated */
152 		die();
153 	if ((data = strchr(data, ':')) == NULL)
154 		goto notfound;
155 	data++;
156 
157 	for (i = 0; i < sizeof(pages)/sizeof(pages[0]); ++i)
158 		if (!strcmp(data, pages[i].name)) {
159 			page = &pages[i];
160 			break;
161 		}
162 
163 	if (page == NULL)
164 		goto notfound;
165 
166 	strlcpy(path, data_path_base, sizeof(path));
167 	strlcat(path, "/", sizeof(path));
168 	if (page->path != NULL)
169 		strlcat(path, page->path, sizeof(path));
170 	else {
171 		strlcat(path, "pages/about_", sizeof(path));
172 		strlcat(path, page->name, sizeof(path));
173 		strlcat(path, ".gmi", sizeof(path));
174 	}
175 
176 	if ((f = fopen(path, "r")) == NULL) {
177 		fs_send_ui(IMSG_BUF, imsg->hdr.peerid, -1,
178 		    page->data, page->len);
179 		fs_send_ui(IMSG_EOF, imsg->hdr.peerid, -1,
180 		    NULL, 0);
181 		return;
182 	}
183 
184 	send_file(imsg->hdr.peerid, f);
185 	return;
186 
187 notfound:
188 	p = "# not found!\n";
189 	fs_send_ui(IMSG_BUF, imsg->hdr.peerid, -1, p, strlen(p));
190 	fs_send_ui(IMSG_EOF, imsg->hdr.peerid, -1, NULL, 0);
191 }
192 
193 static inline void
194 send_hdr(uint32_t peerid, int code, const char *meta)
195 {
196 	fs_send_ui(IMSG_GOT_CODE, peerid, -1, &code, sizeof(code));
197 	fs_send_ui(IMSG_GOT_META, peerid, -1, meta, strlen(meta)+1);
198 }
199 
200 static inline void
201 send_errno(uint32_t peerid, int code, const char *str, int no)
202 {
203 	char *s;
204 
205 	if (asprintf(&s, "%s: %s", str, strerror(no)) == -1)
206 		s = NULL;
207 
208 	send_hdr(peerid, code, s == NULL ? str : s);
209 	free(s);
210 }
211 
212 static inline const char *
213 file_type(const char *path)
214 {
215 	struct mapping {
216 		const char	*ext;
217 		const char	*mime;
218 	} ms[] = {
219 		{"diff",	"text/x-patch"},
220 		{"gemini",	"text/gemini"},
221 		{"gmi",		"text/gemini"},
222 		{"markdown",	"text/plain"},
223 		{"md",		"text/plain"},
224 		{"patch",	"text/x-patch"},
225 		{"txt",		"text/plain"},
226 		{NULL, NULL},
227 	}, *m;
228 	char *dot;
229 
230 	if ((dot = strrchr(path, '.')) == NULL)
231 		return NULL;
232 
233 	dot++;
234 
235 	for (m = ms; m->ext != NULL; ++m)
236 		if (!strcmp(m->ext, dot))
237 			return m->mime;
238 
239 	return NULL;
240 }
241 
242 static int
243 select_non_dot(const struct dirent *d)
244 {
245 	return strcmp(d->d_name, ".");
246 }
247 
248 static int
249 select_non_dotdot(const struct dirent *d)
250 {
251 	return strcmp(d->d_name, ".") && strcmp(d->d_name, "..");
252 }
253 
254 static inline void
255 send_dir(uint32_t peerid, const char *path)
256 {
257 	struct dirent	**names;
258 	struct evbuffer	 *ev;
259 	char		 *s;
260 	int		(*selector)(const struct dirent *) = select_non_dot;
261 	int		  i, len, no;
262 
263 	if (!has_suffix(path, "/")) {
264 		if (asprintf(&s, "%s/", path) == -1)
265 			die();
266 		send_hdr(peerid, 30, s);
267 		free(s);
268 		return;
269 	}
270 
271 	if (!strcmp(path, "/"))
272 		selector = select_non_dotdot;
273 
274 	if ((ev = evbuffer_new()) == NULL ||
275 	    (len = scandir(path, &names, selector, alphasort)) == -1) {
276 		no = errno;
277 		evbuffer_free(ev);
278 		send_errno(peerid, 40, "failure reading the directory", no);
279 		return;
280 	}
281 
282 	evbuffer_add_printf(ev, "# Index of %s\n\n", path);
283 	for (i = 0; i < len; ++i) {
284 		evbuffer_add_printf(ev, "=> %s", names[i]->d_name);
285 		if (names[i]->d_type == DT_DIR)
286 			evbuffer_add(ev, "/", 1);
287 		evbuffer_add(ev, "\n", 1);
288 	}
289 
290 	send_hdr(peerid, 20, "text/gemini");
291 	fs_send_ui(IMSG_BUF, peerid, -1,
292 	    EVBUFFER_DATA(ev), EVBUFFER_LENGTH(ev));
293 	fs_send_ui(IMSG_EOF, peerid, -1, NULL, 0);
294 
295 	evbuffer_free(ev);
296 	free(names);
297 }
298 
299 static void
300 handle_get_file(struct imsg *imsg, size_t datalen)
301 {
302 	struct stat	 sb;
303 	FILE		*f;
304 	char		*data;
305 	const char	*meta = NULL;
306 
307 	data = imsg->data;
308 	data[datalen-1] = '\0';
309 
310 	if ((f = fopen(data, "r")) == NULL) {
311 		send_errno(imsg->hdr.peerid, 51, "can't open", errno);
312 		return;
313 	}
314 
315 	if (fstat(fileno(f), &sb) == -1) {
316 		send_errno(imsg->hdr.peerid, 40, "fstat", errno);
317 		return;
318 	}
319 
320 	if (S_ISDIR(sb.st_mode)) {
321 		fclose(f);
322 		send_dir(imsg->hdr.peerid, data);
323 		return;
324 	}
325 
326 	if ((meta = file_type(data)) == NULL) {
327 		fclose(f);
328 		send_hdr(imsg->hdr.peerid, 51,
329 		    "don't know how to visualize this file");
330 		return;
331 	}
332 
333 	send_hdr(imsg->hdr.peerid, 20, meta);
334 	send_file(imsg->hdr.peerid, f);
335 }
336 
337 static void
338 handle_misc(struct imsg *imsg, size_t datalen)
339 {
340 	switch (imsg->hdr.type) {
341 	case IMSG_INIT:
342 		load_last_session();
343 		break;
344 
345 	case IMSG_QUIT:
346 		if (!safe_mode)
347 			unlink(crashed_file);
348 		event_loopbreak();
349 		break;
350 
351 	default:
352 		die();
353 	}
354 }
355 
356 static void
357 handle_bookmark_page(struct imsg *imsg, size_t datalen)
358 {
359 	char	*data;
360 	int	 res;
361 	FILE	*f;
362 
363 	data = imsg->data;
364 	if (data[datalen-1] != '\0')
365 		die();
366 
367 	if ((f = fopen(bookmark_file, "a")) == NULL) {
368 		res = errno;
369 		goto end;
370 	}
371 	fprintf(f, "=> %s\n", data);
372 	fclose(f);
373 
374 	res = 0;
375 end:
376 	fs_send_ui(IMSG_BOOKMARK_OK, 0, -1, &res, sizeof(res));
377 }
378 
379 static void
380 handle_save_cert(struct imsg *imsg, size_t datalen)
381 {
382 	struct tofu_entry	 e;
383 	FILE			*f;
384 	int			 res;
385 
386 	/* TODO: traverse the file to avoid duplications? */
387 
388 	if (datalen != sizeof(e))
389 		die();
390 	memcpy(&e, imsg->data, datalen);
391 
392 	if ((f = fopen(known_hosts_file, "a")) == NULL) {
393 		res = errno;
394 		goto end;
395 	}
396 	fprintf(f, "%s %s %d\n", e.domain, e.hash, e.verified);
397 	fclose(f);
398 
399 	res = 0;
400 end:
401 	fs_send_ui(IMSG_SAVE_CERT_OK, imsg->hdr.peerid, -1,
402 	    &res, sizeof(res));
403 }
404 
405 static void
406 handle_update_cert(struct imsg *imsg, size_t datalen)
407 {
408 	FILE	*tmp, *f;
409 	struct	 tofu_entry entry;
410 	char	 sfn[PATH_MAX], *line = NULL, *t;
411 	size_t	 l, linesize = 0;
412 	ssize_t	 linelen;
413 	int	 fd, e, res = 0;
414 
415 	if (datalen != sizeof(entry))
416 		die();
417 	memcpy(&entry, imsg->data, datalen);
418 
419 	strlcpy(sfn, known_hosts_tmp, sizeof(sfn));
420 	if ((fd = mkstemp(sfn)) == -1 ||
421 	    (tmp = fdopen(fd, "w")) == NULL) {
422 		if (fd != -1) {
423 			unlink(sfn);
424 			close(fd);
425 		}
426 		res = 0;
427 		goto end;
428 	}
429 
430 	if ((f = fopen(known_hosts_file, "r")) == NULL) {
431 		unlink(sfn);
432 		fclose(tmp);
433                 res = 0;
434 		goto end;
435 	}
436 
437 	l = strlen(entry.domain);
438 	while ((linelen = getline(&line, &linesize, f)) != -1) {
439 		if ((t = strstr(line, entry.domain)) != NULL &&
440 		    (line[l] == ' ' || line[l] == '\t'))
441 			continue;
442 		/* line has a trailing \n */
443 		fprintf(tmp, "%s", line);
444 	}
445 	fprintf(tmp, "%s %s %d\n", entry.domain, entry.hash, entry.verified);
446 
447 	free(line);
448 	e = ferror(tmp);
449 
450 	fclose(tmp);
451 	fclose(f);
452 
453 	if (e) {
454 		unlink(sfn);
455 		res = 0;
456 		goto end;
457 	}
458 
459 	res = rename(sfn, known_hosts_file) != -1;
460 
461 end:
462 	fs_send_ui(IMSG_UPDATE_CERT_OK, imsg->hdr.peerid, -1,
463 	    &res, sizeof(res));
464 }
465 
466 static void
467 handle_file_open(struct imsg *imsg, size_t datalen)
468 {
469 	char	*path, *e;
470 	int	 fd;
471 
472 	path = imsg->data;
473 	if (path[datalen-1] != '\0')
474 		die();
475 
476 	if ((fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, 0644)) == -1) {
477 		e = strerror(errno);
478 		fs_send_ui(IMSG_FILE_OPENED, imsg->hdr.peerid, -1,
479 		    e, strlen(e)+1);
480 	} else
481 		fs_send_ui(IMSG_FILE_OPENED, imsg->hdr.peerid, fd,
482 		    NULL, 0);
483 }
484 
485 static void
486 handle_session_start(struct imsg *imsg, size_t datalen)
487 {
488 	if (datalen != 0)
489 		die();
490 
491 	if ((session = fopen(session_file, "w")) == NULL)
492 		die();
493 }
494 
495 static void
496 handle_session_tab(struct imsg *imsg, size_t datalen)
497 {
498 	struct session_tab	tab;
499 
500 	if (session == NULL)
501 		die();
502 
503 	if (datalen != sizeof(tab))
504 		die();
505 
506 	memcpy(&tab, imsg->data, sizeof(tab));
507 	if (tab.uri[sizeof(tab.uri)-1] != '\0' ||
508 	    tab.title[sizeof(tab.title)-1] != '\0')
509 		die();
510 
511 	fprintf(session, "%s", tab.uri);
512 
513 	if (tab.flags & TAB_CURRENT)
514 		fprintf(session, " current ");
515 	else
516 		fprintf(session, " - ");
517 
518 	fprintf(session, "%s\n", tab.title);
519 }
520 
521 static void
522 handle_session_tab_hist(struct imsg *imsg, size_t datalen)
523 {
524 	struct session_tab_hist th;
525 
526 	if (session == NULL)
527 		die();
528 
529 	if (datalen != sizeof(th))
530 		die();
531 
532 	memcpy(&th, imsg->data, sizeof(th));
533 	if (th.uri[sizeof(th.uri)-1] != '\0')
534 		die();
535 
536 	fprintf(session, "%s %s\n", th.future ? ">" : "<", th.uri);
537 }
538 
539 static void
540 handle_session_end(struct imsg *imsg, size_t datalen)
541 {
542 	if (session == NULL)
543 		die();
544 	fclose(session);
545 	session = NULL;
546 }
547 
548 static void
549 handle_dispatch_imsg(int fd, short ev, void *d)
550 {
551 	struct imsgev	*iev = d;
552 	int		 e;
553 
554 	if (dispatch_imsg(iev, ev, handlers, sizeof(handlers)) == -1) {
555 		/*
556 		 * This should leave a ~/.cache/telescope/crashed file to
557 		 * trigger about:crash on next run.  Unfortunately, if
558 		 * the main process dies the fs sticks around and
559 		 * doesn't notice that the fd was closed.  Why EV_READ
560 		 * is not triggered when a fd is closed on the other end?
561 		 */
562 		e = errno;
563 		if ((fd = open(crashed_file, O_CREAT|O_TRUNC|O_WRONLY, 0600))
564 		    == -1)
565 			err(1, "open");
566 		close(fd);
567 		errx(1, "connection closed: %s", strerror(e));
568 	}
569 }
570 
571 static int
572 fs_send_ui(int type, uint32_t peerid, int fd, const void *data,
573     uint16_t datalen)
574 {
575 	return imsg_compose_event(iev_ui, type, peerid, 0, fd,
576 	    data, datalen);
577 }
578 
579 static size_t
580 join_path(char *buf, const char *lhs, const char *rhs, size_t buflen)
581 {
582 	strlcpy(buf, lhs, buflen);
583 	return strlcat(buf, rhs, buflen);
584 }
585 
586 static void
587 getenv_default(char *buf, const char *name, const char *def, size_t buflen)
588 {
589 	size_t ret;
590 	char *home, *env;
591 
592 	if ((home = getenv("HOME")) == NULL)
593 		errx(1, "HOME is not defined");
594 
595 	if ((env = getenv(name)) != NULL)
596 		ret = strlcpy(buf, env, buflen);
597 	else
598 		ret = join_path(buf, home, def, buflen);
599 
600 	if (ret >= buflen)
601 		errx(1, "buffer too small for %s", name);
602 }
603 
604 static void
605 mkdirs(const char *path, mode_t mode)
606 {
607 	char copy[PATH_MAX+1], orig[PATH_MAX+1], *parent;
608 
609 	strlcpy(copy, path, sizeof(copy));
610 	strlcpy(orig, path, sizeof(orig));
611 	parent = dirname(copy);
612 	if (!strcmp(parent, "/"))
613 		return;
614 	mkdirs(parent, mode);
615 
616 	if (mkdir(orig, mode) != 0) {
617 		if (errno == EEXIST)
618 			return;
619 		err(1, "can't mkdir %s", orig);
620 	}
621 }
622 
623 static void
624 xdg_init(void)
625 {
626 	char *home, old_path[PATH_MAX];
627 	struct stat info;
628 
629 	/* old path */
630 	if ((home = getenv("HOME")) == NULL)
631 		errx(1, "HOME is not defined");
632 	join_path(old_path, home, "/.telescope", sizeof(old_path));
633 
634 	/* if ~/.telescope exists, use that instead of xdg dirs */
635 	if (stat(old_path, &info) == 0 && S_ISDIR(info.st_mode)) {
636 		join_path(config_path_base, home, "/.telescope",
637 		    sizeof(config_path_base));
638 		join_path(data_path_base, home, "/.telescope",
639 		    sizeof(data_path_base));
640 		join_path(cache_path_base, home, "/.telescope",
641 		    sizeof(cache_path_base));
642 		return;
643 	}
644 
645 	/* xdg paths */
646 	getenv_default(xdg_config_base, "XDG_CONFIG_HOME", "/.config",
647 	    sizeof(xdg_config_base));
648 	getenv_default(xdg_data_base, "XDG_DATA_HOME", "/.local/share",
649 	    sizeof(xdg_data_base));
650 	getenv_default(xdg_cache_base, "XDG_CACHE_HOME", "/.cache",
651 	    sizeof(xdg_cache_base));
652 
653 	join_path(config_path_base, xdg_config_base, "/telescope",
654 	    sizeof(config_path_base));
655 	join_path(data_path_base, xdg_data_base, "/telescope",
656 	    sizeof(data_path_base));
657 	join_path(cache_path_base, xdg_cache_base, "/telescope",
658 	    sizeof(cache_path_base));
659 
660 	mkdirs(xdg_config_base, S_IRWXU);
661 	mkdirs(xdg_data_base, S_IRWXU);
662 	mkdirs(xdg_cache_base, S_IRWXU);
663 
664 	mkdirs(config_path_base, S_IRWXU);
665 	mkdirs(data_path_base, S_IRWXU);
666 	mkdirs(cache_path_base, S_IRWXU);
667 }
668 
669 int
670 fs_init(void)
671 {
672 	xdg_init();
673 
674 	join_path(config_path, config_path_base, "/config",
675 	    sizeof(config_path));
676 	join_path(lockfile_path, cache_path_base, "/lock",
677 	    sizeof(lockfile_path));
678 	join_path(bookmark_file, data_path_base, "/bookmarks.gmi",
679 	    sizeof(bookmark_file));
680 	join_path(known_hosts_file, data_path_base, "/known_hosts",
681 	    sizeof(known_hosts_file));
682 	join_path(known_hosts_tmp, cache_path_base,
683 	    "/known_hosts.tmp.XXXXXXXXXX", sizeof(known_hosts_tmp));
684 	join_path(session_file, cache_path_base, "/session",
685 	    sizeof(session_file));
686 	join_path(crashed_file, cache_path_base, "/crashed",
687 	    sizeof(crashed_file));
688 
689 	return 1;
690 }
691 
692 /*
693  * Parse a line of the session file.  The format is:
694  *
695  *	URL [flags,...] [title]\n
696  */
697 static void
698 parse_session_line(char *line, const char **title, uint32_t *flags)
699 {
700 	char *s, *t, *ap;
701 
702 	*title = "";
703 	*flags = 0;
704 	if ((s = strchr(line, ' ')) == NULL)
705 		return;
706 
707 	*s++ = '\0';
708 
709 	if ((t = strchr(s, ' ')) != NULL) {
710 		*t++ = '\0';
711 		*title = t;
712 	}
713 
714 	while ((ap = strsep(&s, ",")) != NULL) {
715 		if (!strcmp(ap, "current"))
716 			*flags |= TAB_CURRENT;
717 	}
718 }
719 
720 static inline void
721 sendtab(uint32_t flags, const char *uri, const char *title)
722 {
723 	struct session_tab tab;
724 
725 	memset(&tab, 0, sizeof(tab));
726 	tab.flags = flags;
727 
728 	if (strlcpy(tab.uri, uri, sizeof(tab.uri)) >= sizeof(tab.uri))
729 		return;
730 
731 	/* don't worry about cached title truncation */
732 	if (title != NULL)
733 		strlcpy(tab.title, title, sizeof(tab.title));
734 
735 	fs_send_ui(IMSG_SESSION_TAB, 0, -1, &tab, sizeof(tab));
736 }
737 
738 static inline void
739 sendhist(const char *uri, int future)
740 {
741 	struct session_tab_hist sth;
742 
743 	memset(&sth, 0, sizeof(sth));
744 	sth.future = future;
745 
746 	if (strlcpy(sth.uri, uri, sizeof(sth.uri)) >= sizeof(sth.uri))
747 		return;
748 
749 	fs_send_ui(IMSG_SESSION_TAB_HIST, 0, -1, &sth, sizeof(sth));
750 }
751 
752 static void
753 load_last_session(void)
754 {
755 	FILE		*session;
756 	uint32_t	 flags;
757 	size_t		 linesize = 0;
758 	ssize_t		 linelen;
759 	int		 first_time = 0;
760 	int		 future;
761 	const char	*title;
762 	char		*nl, *s, *line = NULL;
763 
764 	if ((session = fopen(session_file, "r")) == NULL) {
765 		/* first time? */
766 		first_time = 1;
767 		goto end;
768 	}
769 
770 	while ((linelen = getline(&line, &linesize, session)) != -1) {
771 		if ((nl = strchr(line, '\n')) != NULL)
772 			*nl = '\0';
773 
774 		if (*line == '<' || *line == '>') {
775 			future = *line == '>';
776 			s = line+1;
777 			if (*s != ' ')
778 				continue;
779 			sendhist(++s, future);
780 		} else {
781 			parse_session_line(line, &title, &flags);
782 			sendtab(flags, line, title);
783 		}
784 	}
785 
786 	fclose(session);
787 	free(line);
788 
789 	if (last_time_crashed())
790 		sendtab(TAB_CURRENT, "about:crash", NULL);
791 
792 end:
793 	fs_send_ui(IMSG_SESSION_END, 0, -1, &first_time, sizeof(first_time));
794 }
795 
796 int
797 fs_main(void)
798 {
799 	setproctitle("fs");
800 
801 	fs_init();
802 
803 	event_init();
804 
805 	/* Setup pipe and event handler to the main process */
806 	if ((iev_ui = malloc(sizeof(*iev_ui))) == NULL)
807 		die();
808 	imsg_init(&iev_ui->ibuf, 3);
809 	iev_ui->handler = handle_dispatch_imsg;
810 	iev_ui->events = EV_READ;
811 	event_set(&iev_ui->ev, iev_ui->ibuf.fd, iev_ui->events,
812 	    iev_ui->handler, iev_ui);
813 	event_add(&iev_ui->ev, NULL);
814 
815 	sandbox_fs_process();
816 
817 	event_dispatch();
818 	return 0;
819 }
820 
821 
822 
823 /*
824  * Check if the last time telescope crashed.  The check is done by
825  * looking at `crashed_file': if it exists then last time we crashed.
826  * Then, while here, touch the file too.  During IMSG_QUIT we'll
827  * remove it.
828  */
829 int
830 last_time_crashed(void)
831 {
832 	int fd, crashed = 1;
833 
834 	if (safe_mode)
835 		return 0;
836 
837 	if (unlink(crashed_file) == -1 && errno == ENOENT)
838 		crashed = 0;
839 
840 	if ((fd = open(crashed_file, O_CREAT|O_WRONLY, 0600)) == -1)
841 		return crashed;
842 	close(fd);
843 
844 	return crashed;
845 }
846 
847 int
848 lock_session(void)
849 {
850 	struct flock	lock;
851 	int		fd;
852 
853 	if ((fd = open(lockfile_path, O_WRONLY|O_CREAT, 0600)) == -1)
854 		return -1;
855 
856 	lock.l_start = 0;
857 	lock.l_len = 0;
858 	lock.l_type = F_WRLCK;
859 	lock.l_whence = SEEK_SET;
860 
861 	if (fcntl(fd, F_SETLK, &lock) == -1) {
862 		close(fd);
863 		return -1;
864 	}
865 
866 	return fd;
867 }
868 
869 static int
870 parse_khost_line(char *line, char *tmp[3])
871 {
872 	char **ap;
873 
874 	for (ap = tmp; ap < &tmp[3] &&
875 	    (*ap = strsep(&line, " \t\n")) != NULL;) {
876 		if (**ap != '\0')
877 			ap++;
878 	}
879 
880 	return ap == &tmp[3] && *line == '\0';
881 }
882 
883 int
884 load_certs(struct ohash *h)
885 {
886 	char		*tmp[3], *line = NULL;
887 	const char	*errstr;
888 	size_t		 lineno = 0, linesize = 0;
889 	ssize_t		 linelen;
890 	FILE		*f;
891 	struct tofu_entry *e;
892 
893 	if ((f = fopen(known_hosts_file, "r")) == NULL)
894 		return 0;
895 
896 	while ((linelen = getline(&line, &linesize, f)) != -1) {
897 		if ((e = calloc(1, sizeof(*e))) == NULL)
898 			abort();
899 
900 		lineno++;
901 
902 		if (parse_khost_line(line, tmp)) {
903 			strlcpy(e->domain, tmp[0], sizeof(e->domain));
904 			strlcpy(e->hash, tmp[1], sizeof(e->hash));
905 
906 			e->verified = strtonum(tmp[2], 0, 1, &errstr);
907 			if (errstr != NULL)
908 				errx(1, "%s:%zu verification for %s is %s: %s",
909 				    known_hosts_file, lineno,
910 				    e->domain, errstr, tmp[2]);
911 			tofu_add(h, e);
912 		} else {
913 			warnx("%s:%zu invalid entry",
914 			    known_hosts_file, lineno);
915 			free(e);
916 		}
917 	}
918 
919 	free(line);
920 	return ferror(f);
921 }
922