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