1 /*
2  * Copyright (c) 2021 Omar Polo <op@omarpolo.com>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include "compat.h"
18 
19 #include <errno.h>
20 #include <fcntl.h>
21 #include <limits.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <time.h>
26 #include <unistd.h>
27 
28 #include "defaults.h"
29 #include "fs.h"
30 #include "minibuffer.h"
31 #include "session.h"
32 #include "ui.h"
33 
34 struct history	history;
35 
36 static struct event	 autosaveev;
37 
38 void
39 switch_to_tab(struct tab *tab)
40 {
41 	current_tab = tab;
42 	tab->flags &= ~TAB_URGENT;
43 
44 	if (operating && tab->flags & TAB_LAZY)
45 		load_url_in_tab(tab, tab->hist_cur->h, NULL, LU_MODE_NOHIST);
46 }
47 
48 unsigned int
49 tab_new_id(void)
50 {
51 	static uint32_t tab_counter;
52 
53 	return tab_counter++;
54 }
55 
56 struct tab *
57 new_tab(const char *url, const char *base, struct tab *after)
58 {
59 	struct tab	*tab;
60 
61 	ui_schedule_redraw();
62 	autosave_hook();
63 
64 	if ((tab = calloc(1, sizeof(*tab))) == NULL) {
65 		event_loopbreak();
66 		return NULL;
67 	}
68 
69 	TAILQ_INIT(&tab->hist.head);
70 	TAILQ_INIT(&tab->buffer.head);
71 	TAILQ_INIT(&tab->buffer.page.head);
72 	evtimer_set(&tab->loadingev, NULL, NULL);
73 
74 	tab->id = tab_new_id();
75 
76 	if (after != NULL)
77 		TAILQ_INSERT_AFTER(&tabshead, after, tab, tabs);
78 	else
79 		TAILQ_INSERT_TAIL(&tabshead, tab, tabs);
80 
81 	if (!operating)
82 		tab->flags |= TAB_LAZY;
83 	load_url_in_tab(tab, url, base, 0);
84 	switch_to_tab(tab);
85 	return tab;
86 }
87 
88 /*
89  * Move a tab from the tablist to the killed tab list and erase its
90  * contents.  Append should always be 0 to prepend tabs so unkill_tab
91  * can work correctly; appending is only useful during startup when
92  * receiving the list of killed tabs to keep the correct order.
93  * NB: doesn't update the current_tab.
94  */
95 void
96 kill_tab(struct tab *tab, int append)
97 {
98 	int count;
99 
100 	stop_tab(tab);
101 	erase_buffer(&tab->buffer);
102 	TAILQ_REMOVE(&tabshead, tab, tabs);
103 	ui_schedule_redraw();
104 	autosave_hook();
105 
106 	if (evtimer_pending(&tab->loadingev, NULL))
107 		evtimer_del(&tab->loadingev);
108 
109 	if (append)
110 		TAILQ_INSERT_TAIL(&ktabshead, tab, tabs);
111 	else
112 		TAILQ_INSERT_HEAD(&ktabshead, tab, tabs);
113 
114 	/* gc closed tabs */
115 	count = 0;
116 	TAILQ_FOREACH(tab, &ktabshead, tabs)
117 		count++;
118 	while (count > max_killed_tabs) {
119 		count--;
120 		free_tab(TAILQ_LAST(&ktabshead, tabshead));
121 	}
122 }
123 
124 /*
125  * Resurrects the lastest killed tab and returns it.  The tab is already
126  * added to the tab list with the TAB_LAZY flag set.  NB: this doesn't
127  * update current_tab.
128  */
129 struct tab *
130 unkill_tab(void)
131 {
132 	struct tab *t;
133 
134 	if (TAILQ_EMPTY(&ktabshead))
135 		return NULL;
136 
137 	ui_schedule_redraw();
138 	autosave_hook();
139 
140 	t = TAILQ_FIRST(&ktabshead);
141 	TAILQ_REMOVE(&ktabshead, t, tabs);
142 	TAILQ_INSERT_TAIL(&tabshead, t, tabs);
143 	t->flags |= TAB_LAZY;
144 	return t;
145 }
146 
147 /*
148  * Free every resource linked to the tab, including the tab itself, and
149  * removes it from the *killed* tablist.
150  */
151 void
152 free_tab(struct tab *tab)
153 {
154 	TAILQ_REMOVE(&ktabshead, tab, tabs);
155 	hist_clear(&tab->hist);
156 	free(tab);
157 }
158 
159 void
160 stop_tab(struct tab *tab)
161 {
162 	ui_send_net(IMSG_STOP, tab->id, NULL, 0);
163 }
164 
165 static inline void
166 savetab(FILE *fp, struct tab *tab, int killed)
167 {
168 	struct hist	*h;
169 	size_t		 top_line, current_line;
170 	int		 future;
171 
172 	get_scroll_position(tab, &top_line, &current_line);
173 
174 	fprintf(fp, "%s ", tab->hist_cur->h);
175 	if (tab == current_tab)
176 		fprintf(fp, "current,");
177 	if (killed)
178 		fprintf(fp, "killed,");
179 
180 	fprintf(fp, "top=%zu,cur=%zu %s\n", top_line, current_line,
181 	    tab->buffer.page.title);
182 
183 	future = 0;
184 	TAILQ_FOREACH(h, &tab->hist.head, entries) {
185 		if (h == tab->hist_cur) {
186 			future = 1;
187 			continue;
188 		}
189 
190 		fprintf(fp, "%s %s\n", future ? ">" : "<", h->h);
191 	}
192 }
193 
194 static void
195 save_tabs(void)
196 {
197 	FILE		*fp;
198 	struct tab	*tab;
199 	int		 fd, err;
200 	char		 sfn[PATH_MAX];
201 
202 	strlcpy(sfn, session_file_tmp, sizeof(sfn));
203 	if ((fd = mkstemp(sfn)) == -1 ||
204 	    (fp = fdopen(fd, "w")) == NULL) {
205 		if (fd != -1) {
206 			unlink(sfn);
207 			close(fd);
208 		}
209 		return;
210 	}
211 
212 	TAILQ_FOREACH(tab, &tabshead, tabs)
213 		savetab(fp, tab, 0);
214 	TAILQ_FOREACH(tab, &ktabshead, tabs)
215 		savetab(fp, tab, 1);
216 
217 	err = fflush(fp) == EOF;
218 	fclose(fp);
219 
220 	if (err || rename(sfn, session_file) == -1)
221 		unlink(sfn);
222 }
223 
224 static void
225 save_all_history(void)
226 {
227 	FILE	*fp;
228 	size_t	 i;
229 	int	 fd, err;
230 	char	 sfn[PATH_MAX];
231 
232 	strlcpy(sfn, history_file_tmp, sizeof(sfn));
233 	if ((fd = mkstemp(sfn)) == -1 ||
234 	    (fp = fdopen(fd, "w")) == NULL) {
235 		if (fd != -1) {
236 			unlink(sfn);
237 			close(fd);
238 		}
239 		return;
240 	}
241 
242 	for (i = 0; i < history.len; ++i) {
243 		history.items[i].dirty = 0;
244 		fprintf(fp, "%lld %s\n", (long long)history.items[i].ts,
245 		    history.items[i].uri);
246 	}
247 
248 	err = fflush(fp) == EOF;
249 	fclose(fp);
250 
251 	if (err || rename(sfn, history_file) == -1) {
252 		unlink(sfn);
253 		return;
254 	}
255 
256 	history.dirty = 0;
257 	history.extra = 0;
258 }
259 
260 static void
261 save_dirty_history(void)
262 {
263 	FILE	*fp;
264 	size_t	 i;
265 
266 	if ((fp = fopen(history_file, "a")) == NULL)
267 		return;
268 
269 	for (i = 0; i < history.len && history.dirty > 0; ++i) {
270 		if (!history.items[i].dirty)
271 			continue;
272 		history.dirty--;
273 		history.items[i].dirty = 0;
274 		fprintf(fp, "%lld %s\n", (long long)history.items[i].ts,
275 		    history.items[i].uri);
276 	}
277 	history.dirty = 0;
278 
279 	fclose(fp);
280 }
281 
282 void
283 save_session(void)
284 {
285 	if (safe_mode)
286 		return;
287 
288 	save_tabs();
289 
290 	if (history.extra > HISTORY_CAP/2)
291 		save_all_history();
292 	else if (history.dirty)
293 		save_dirty_history();
294 }
295 
296 void
297 history_push(struct histitem *hi)
298 {
299 	size_t		 i, oldest = 0;
300 	char		*uri;
301 
302 	for (i = 0; i < history.len; ++i) {
303 		if (history.items[i].ts < history.items[oldest].ts)
304 			oldest = i;
305 
306 		/* remove duplicates */
307 		if (!strcmp(history.items[i].uri, hi->uri))
308 			return;
309 	}
310 
311 	if ((uri = strdup(hi->uri)) == NULL)
312 		abort();
313 
314 	/* don't grow too much; replace the oldest */
315 	if (history.len == HISTORY_CAP) {
316 		history.items[oldest].ts = hi->ts;
317 		free(history.items[oldest].uri);
318 		history.items[oldest].uri = uri;
319 
320 		/* Growed past the max value, signal to regen the file. */
321 		history.extra++;
322 		return;
323 	}
324 
325 	history.items[history.len].ts = hi->ts;
326 	history.items[history.len].uri = uri;
327 	history.len++;
328 }
329 
330 static int
331 history_cmp(const void *a, const void *b)
332 {
333 	const struct history_item *i = a, *j = b;
334 	return strcmp(i->uri, j->uri);
335 }
336 
337 void
338 history_sort(void)
339 {
340 	qsort(history.items, history.len, sizeof(history.items[0]),
341 	    history_cmp);
342 }
343 
344 void
345 history_add(const char *uri)
346 {
347 	size_t	 i, j, insert = 0, oldest = 0;
348 	char	*u;
349 	int	 c;
350 
351 	for (i = 0; i < history.len; ++i) {
352 		if (history.items[i].ts < history.items[oldest].ts)
353 			oldest = i;
354 
355 		if (insert != 0 && insert < i)
356 			continue;
357 
358 		c = strcmp(uri, history.items[i].uri);
359 		if (c == 0) {
360 			history.items[i].ts = time(NULL);
361 			history.items[i].dirty = 1;
362 			history.dirty++;
363 			autosave_hook();
364 			return;
365 		}
366 
367 		if (c > 0)
368 			insert = i;
369 	}
370 
371 	if ((u = strdup(uri)) == NULL)
372 		return;
373 
374 	/* if history is full, replace the oldest one */
375 	if (history.len == HISTORY_CAP) {
376 		free(history.items[oldest].uri);
377 		history.items[oldest].uri = u;
378 		history.items[oldest].ts = time(NULL);
379 		history.items[oldest].dirty = 1;
380 		history.dirty++;
381 		history_sort();
382 		autosave_hook();
383 		return;
384 	}
385 
386 	/* otherwise just insert in the right spot */
387 
388 	for (j = history.len; j > insert; --j)
389 		memcpy(&history.items[j], &history.items[j-1],
390 		    sizeof(history.items[j]));
391 
392 	history.items[insert].ts = time(NULL);
393 	history.items[insert].uri = u;
394 	history.items[insert].dirty = 1;
395 	history.dirty++;
396 	history.len++;
397 	autosave_hook();
398 }
399 
400 void
401 autosave_init(void)
402 {
403 	evtimer_set(&autosaveev, autosave_timer, NULL);
404 }
405 
406 void
407 autosave_timer(int fd, short event, void *data)
408 {
409 	save_session();
410 }
411 
412 /*
413  * Function to be called in "interesting" places where we may want to
414  * schedule an autosave (like on new tab or before loading an url.)
415  */
416 void
417 autosave_hook(void)
418 {
419 	struct timeval tv;
420 
421 	if (autosave <= 0)
422 		return;
423 
424 	if (!evtimer_pending(&autosaveev, NULL)) {
425 		tv.tv_sec = autosave;
426 		tv.tv_usec = 0;
427 
428 		evtimer_add(&autosaveev, &tv);
429 	}
430 }
431 
432 static inline int
433 parse_khost_line(char *line, char *tmp[3])
434 {
435 	char **ap;
436 
437 	for (ap = tmp; ap < &tmp[3] &&
438 	    (*ap = strsep(&line, " \t\n")) != NULL;) {
439 		if (**ap != '\0')
440 			ap++;
441 	}
442 
443 	return ap == &tmp[3] && *line == '\0';
444 }
445 
446 static void
447 load_certs(struct ohash *certs)
448 {
449 	char		*tmp[3], *line = NULL;
450 	const char	*errstr;
451 	size_t		 lineno = 0, linesize = 0;
452 	ssize_t		 linelen;
453 	FILE		*f;
454 	struct tofu_entry *e;
455 
456 	if ((f = fopen(known_hosts_file, "r")) == NULL)
457 		return;
458 
459 	if ((e = calloc(1, sizeof(*e))) == NULL) {
460 		fclose(f);
461 		return;
462 	}
463 
464 	while ((linelen = getline(&line, &linesize, f)) != -1) {
465 		lineno++;
466 
467 		if (parse_khost_line(line, tmp)) {
468 			strlcpy(e->domain, tmp[0], sizeof(e->domain));
469 			strlcpy(e->hash, tmp[1], sizeof(e->hash));
470 
471 			e->verified = strtonum(tmp[2], 0, 1, &errstr);
472 			if (errstr != NULL)
473 				errx(1, "%s:%zu verification for %s is %s: %s",
474 				    known_hosts_file, lineno,
475 				    e->domain, errstr, tmp[2]);
476 
477 			tofu_add(certs, e);
478 		} else
479 			warnx("%s:%zu invalid entry",
480 			    known_hosts_file, lineno);
481 	}
482 
483 	free(line);
484 	fclose(f);
485 	return;
486 }
487 
488 
489 static void
490 load_hist(void)
491 {
492 	FILE		*hist;
493 	size_t		 linesize = 0;
494 	ssize_t		 linelen;
495 	char		*nl, *spc, *line = NULL;
496 	const char	*errstr;
497 	struct histitem	 hi;
498 
499 	if ((hist = fopen(history_file, "r")) == NULL)
500 		return;
501 
502 	while ((linelen = getline(&line, &linesize, hist)) != -1) {
503 		if ((nl = strchr(line, '\n')) != NULL)
504 			*nl = '\0';
505 		if ((spc = strchr(line, ' ')) == NULL)
506 			continue;
507 		*spc = '\0';
508 		spc++;
509 
510 		memset(&hi, 0, sizeof(hi));
511 		hi.ts = strtonum(line, INT64_MIN, INT64_MAX, &errstr);
512 		if (errstr != NULL)
513 			continue;
514 		if (strlcpy(hi.uri, spc, sizeof(hi.uri)) >= sizeof(hi.uri))
515 			continue;
516 
517 		history_push(&hi);
518 	}
519 
520 	fclose(hist);
521 	free(line);
522 
523 	history_sort();
524 }
525 
526 /*
527  * Check if the last time telescope crashed.  The check is done by
528  * looking at `crashed_file': if it exists then last time we crashed.
529  * Then, while here, touch the file too, it's removed during the
530  * teardown.
531  */
532 static int
533 last_time_crashed(void)
534 {
535 	int fd, crashed = 1;
536 
537 	if (safe_mode)
538 		return 0;
539 
540 	if (unlink(crashed_file) == -1 && errno == ENOENT)
541 		crashed = 0;
542 
543 	if ((fd = open(crashed_file, O_CREAT|O_WRONLY, 0600)) == -1)
544 		return crashed;
545 	close(fd);
546 
547 	return crashed;
548 }
549 
550 /*
551  * Parse and restore a tab from the session file.  The format is:
552  *
553  *	URL [flags,...] [title]\n
554  */
555 static inline struct tab *
556 parse_tab_line(char *line, struct tab **ct)
557 {
558 	struct tab *tab;
559 	char *s, *t, *ap;
560 	const char *uri, *title = "";
561 	int current = 0, killed = 0;
562 	size_t tline = 0, cline = 0;
563 
564 	uri = line;
565 	if ((s = strchr(line, ' ')) == NULL)
566 		return NULL;
567 	*s++ = '\0';
568 
569 	if ((t = strchr(s, ' ')) != NULL) {
570 		*t++ = '\0';
571 		title = t;
572 	}
573 
574 	while ((ap = strsep(&s, ",")) != NULL) {
575 		if (!strcmp(ap, "current"))
576 			current = 1;
577 		else if (!strcmp(ap, "killed"))
578 			killed = 1;
579 		else if (!strncmp(ap, "top=", 4))
580 			tline = strtonum(ap+4, 0, UINT32_MAX, NULL);
581 		else if (!strncmp(ap, "cur=", 4))
582 			cline = strtonum(ap + 4, 0, UINT32_MAX, NULL);
583 	}
584 
585 	if (tline > cline) {
586 		tline = 0;
587 		cline = 0;
588 	}
589 
590 	if ((tab = new_tab(uri, NULL, NULL)) == NULL)
591 		err(1, "new_tab");
592 	tab->hist_cur->line_off = tline;
593 	tab->hist_cur->current_off = cline;
594 	strlcpy(tab->buffer.page.title, title, sizeof(tab->buffer.page.title));
595 
596 	if (current)
597 		*ct = tab;
598 	else if (killed)
599 		kill_tab(tab, 1);
600 
601 	return tab;
602 }
603 
604 static void
605 load_tabs(void)
606 {
607 	struct tab	*tab = NULL, *ct = NULL;
608 	struct hist	*h;
609 	FILE		*session;
610 	size_t		 lineno = 0, linesize = 0;
611 	ssize_t		 linelen;
612 	char		*uri, *line = NULL;
613 
614 	if ((session = fopen(session_file, "r")) == NULL) {
615 		new_tab("about:new", NULL, NULL);
616 		new_tab("about:help", NULL, NULL);
617 		return;
618 	}
619 
620 	while ((linelen = getline(&line, &linesize, session)) != -1) {
621 		lineno++;
622 
623 		if (linelen > 0 && line[linelen-1] == '\n')
624 			line[linelen-1] = '\0';
625 
626 		if (*line == '<' || *line == '>') {
627 			uri = line + 1;
628 			if (*uri != ' ' || tab == NULL) {
629 				fprintf(stderr, "%s:%zu invalid line\n",
630 				    session_file, lineno);
631 				continue;
632 			}
633 			uri++;
634 
635 			if ((h = calloc(1, sizeof(*h))) == NULL)
636 				err(1, "calloc");
637 			strlcpy(h->h, uri, sizeof(h->h));
638 
639 			if (*line == '>') /* future hist */
640 				hist_push(&tab->hist, h);
641 			else
642 				hist_add_before(&tab->hist, tab->hist_cur, h);
643 		} else
644 			tab = parse_tab_line(line, &ct);
645 	}
646 
647 	fclose(session);
648 	free(line);
649 
650 	if (ct == NULL || TAILQ_EMPTY(&tabshead))
651 		ct = new_tab("about:new", NULL, NULL);
652 
653 	switch_to_tab(ct);
654 
655 	if (last_time_crashed())
656 		new_tab("about:crash", NULL, NULL);
657 }
658 
659 int
660 load_session(struct ohash *certs)
661 {
662 	load_certs(certs);
663 	load_hist();
664 	load_tabs();
665 	return 0;
666 }
667 
668 int
669 lock_session(void)
670 {
671 	struct flock	lock;
672 	int		fd;
673 
674 	if ((fd = open(lockfile_path, O_WRONLY|O_CREAT, 0600)) == -1)
675 		return -1;
676 
677 	lock.l_start = 0;
678 	lock.l_len = 0;
679 	lock.l_type = F_WRLCK;
680 	lock.l_whence = SEEK_SET;
681 
682 	if (fcntl(fd, F_SETLK, &lock) == -1) {
683 		close(fd);
684 		return -1;
685 	}
686 
687 	return fd;
688 }