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 "pages.h"
37 #include "parser.h"
38 #include "session.h"
39 #include "telescope.h"
40 #include "utils.h"
41 
42 #include "fs.h"
43 
44 #ifndef nitems
45 #define nitems(x)  (sizeof(x) / sizeof(x[0]))
46 #endif
47 
48 static void		 die(void) __attribute__((__noreturn__));
49 static int		 select_non_dot(const struct dirent *);
50 static int		 select_non_dotdot(const struct dirent *);
51 static size_t		 join_path(char*, const char*, const char*, size_t);
52 static void		 getenv_default(char*, const char*, const char*, size_t);
53 static void		 mkdirs(const char*, mode_t);
54 static void		 init_paths(void);
55 static void		 load_last_session(void);
56 static void		 load_hist(void);
57 static int		 last_time_crashed(void);
58 static void		 load_certs(struct ohash *);
59 
60 /*
61  * Where to store user data.  These are all equal to ~/.telescope if
62  * it exists.
63  */
64 char		config_path_base[PATH_MAX];
65 char		data_path_base[PATH_MAX];
66 char		cache_path_base[PATH_MAX];
67 
68 char		ctlsock_path[PATH_MAX];
69 char		config_path[PATH_MAX];
70 char		lockfile_path[PATH_MAX];
71 char		bookmark_file[PATH_MAX];
72 char		known_hosts_file[PATH_MAX], known_hosts_tmp[PATH_MAX];
73 char		crashed_file[PATH_MAX];
74 char		session_file[PATH_MAX];
75 char		history_file[PATH_MAX];
76 
77 static void __attribute__((__noreturn__))
78 die(void)
79 {
80 	abort(); 		/* TODO */
81 }
82 
83 static int
84 select_non_dot(const struct dirent *d)
85 {
86 	return strcmp(d->d_name, ".");
87 }
88 
89 static int
90 select_non_dotdot(const struct dirent *d)
91 {
92 	return strcmp(d->d_name, ".") && strcmp(d->d_name, "..");
93 }
94 
95 static void
96 send_dir(struct tab *tab, const char *path)
97 {
98 	struct dirent	**names;
99 	int		(*selector)(const struct dirent *) = select_non_dot;
100 	int		  i, len;
101 
102 #if notyet
103 	/*
104 	 * need something to fake a redirect
105 	 */
106 
107 	if (!has_suffix(path, "/")) {
108 		if (asprintf(&s, "%s/", path) == -1)
109 			die();
110 		send_hdr(peerid, 30, s);
111 		free(s);
112 		return;
113 	}
114 #endif
115 
116 	if (!strcmp(path, "/"))
117 		selector = select_non_dotdot;
118 
119 	if ((len = scandir(path, &names, selector, alphasort)) == -1) {
120 		load_page_from_str(tab, "# failure reading the directory\n");
121 		return;
122 	}
123 
124 	parser_init(tab, gemtext_initparser);
125 	parser_parsef(tab, "# Index of %s\n\n", path);
126 
127 	for (i = 0; i < len; ++i) {
128 		const char *sufx = "";
129 
130 		if (names[i]->d_type == DT_DIR)
131 			sufx = "/";
132 
133 		parser_parsef(tab, "=> %s%s\n", names[i]->d_name, sufx);
134 	}
135 
136 	parser_free(tab);
137 	free(names);
138 }
139 
140 static int
141 is_dir(FILE *fp)
142 {
143 	struct stat sb;
144 
145 	if (fstat(fileno(fp), &sb) == -1)
146 		return 0;
147 
148 	return S_ISDIR(sb.st_mode);
149 }
150 
151 static parserinit
152 file_type(const char *path)
153 {
154 	struct mapping {
155 		const char	*ext;
156 		parserinit	 fn;
157 	} ms[] = {
158 		{"diff",	textpatch_initparser},
159 		{"gemini",	gemtext_initparser},
160 		{"gmi",		gemtext_initparser},
161 		{"markdown",	textplain_initparser},
162 		{"md",		textplain_initparser},
163 		{"patch",	gemtext_initparser},
164 		{NULL, NULL},
165 	}, *m;
166 	char *dot;
167 
168 	if ((dot = strrchr(path, '.')) == NULL)
169 		return textplain_initparser;
170 
171 	dot++;
172 
173 	for (m = ms; m->ext != NULL; ++m)
174 		if (!strcmp(m->ext, dot))
175 			return m->fn;
176 
177 	return textplain_initparser;
178 }
179 
180 void
181 fs_load_url(struct tab *tab, const char *url)
182 {
183 	const char	*bpath = "bookmarks.gmi", *fallback = "# Not found\n";
184 	parserinit	 initfn = gemtext_initparser;
185 	char		 path[PATH_MAX];
186 	FILE		*fp = NULL;
187 	size_t		 i;
188 	char		 buf[BUFSIZ];
189 	struct page {
190 		const char	*name;
191 		const char	*path;
192 		const uint8_t	*data;
193 		size_t		 len;
194 	} pages[] = {
195 		{"about",	NULL,	about_about,	about_about_len},
196 		{"blank",	NULL,	about_blank,	about_blank_len},
197 		{"bookmarks",	bpath,	bookmarks,	bookmarks_len},
198 		{"crash",	NULL,	about_crash,	about_crash_len},
199 		{"help",	NULL,	about_help,	about_help_len},
200 		{"license",	NULL,	about_license,	about_license_len},
201 		{"new",		NULL,	about_new,	about_new_len},
202 	}, *page = NULL;
203 
204 	if (!strncmp(url, "about:", 6)) {
205 		url += 6;
206 
207 		for (i = 0; page == NULL && i < nitems(pages); ++i) {
208 			if (!strcmp(url, pages[i].name))
209 				page = &pages[i];
210 		}
211 
212 		if (page == NULL)
213 			goto done;
214 
215 		strlcpy(path, data_path_base, sizeof(path));
216 		strlcat(path, "/", sizeof(path));
217 		if (page->path != NULL)
218 			strlcat(path, page->path, sizeof(path));
219 		else {
220 			strlcat(path, "page/about_", sizeof(path));
221 			strlcat(path, page->name, sizeof(path));
222 			strlcat(path, ".gmi", sizeof(path));
223 		}
224 
225 		fallback = page->data;
226 	} else if (!strncmp(url, "file://", 7)) {
227 		url += 7;
228 		strlcpy(path, url, sizeof(path));
229 		initfn = file_type(url);
230 	} else
231 		goto done;
232 
233 	if ((fp = fopen(path, "r")) == NULL)
234 		goto done;
235 
236 	if (is_dir(fp)) {
237 		fclose(fp);
238 		send_dir(tab, path);
239 		goto done;
240 	}
241 
242 	parser_init(tab, initfn);
243 	for (;;) {
244 		size_t r;
245 
246 		r = fread(buf, 1, sizeof(buf), fp);
247 		if (!parser_parse(tab, buf, r))
248 			break;
249 		if (r != sizeof(buf))
250 			break;
251 	}
252 	parser_free(tab);
253 
254 done:
255 	if (fp != NULL)
256 		fclose(fp);
257 	else
258 		load_page_from_str(tab, fallback);
259 }
260 
261 int
262 bookmark_page(const char *url)
263 {
264 	FILE *f;
265 
266 	if ((f = fopen(bookmark_file, "a")) == NULL)
267 		return -1;
268 	fprintf(f, "=> %s\n", url);
269 	fclose(f);
270 	return 0;
271 }
272 
273 int
274 save_cert(const struct tofu_entry *e)
275 {
276 	FILE *f;
277 
278 	if ((f = fopen(known_hosts_file, "a")) == NULL)
279 		return -1;
280 	fprintf(f, "%s %s %d\n", e->domain, e->hash, e->verified);
281 	fclose(f);
282 	return 0;
283 }
284 
285 int
286 update_cert(const struct tofu_entry *e)
287 {
288 	FILE	*tmp, *f;
289 	char	 sfn[PATH_MAX], *line = NULL, *t;
290 	size_t	 l, linesize = 0;
291 	ssize_t	 linelen;
292 	int	 fd, err;
293 
294 	strlcpy(sfn, known_hosts_tmp, sizeof(sfn));
295 	if ((fd = mkstemp(sfn)) == -1 ||
296 	    (tmp = fdopen(fd, "w")) == NULL) {
297 		if (fd != -1) {
298 			unlink(sfn);
299 			close(fd);
300 		}
301 		return -1;
302 	}
303 
304 	if ((f = fopen(known_hosts_file, "r")) == NULL) {
305 		unlink(sfn);
306 		fclose(tmp);
307 		return -1;
308 	}
309 
310 	l = strlen(e->domain);
311 	while ((linelen = getline(&line, &linesize, f)) != -1) {
312 		if ((t = strstr(line, e->domain)) != NULL &&
313 		    (line[l] == ' ' || line[l] == '\t'))
314 			continue;
315 		/* line has a trailing \n */
316 		fprintf(tmp, "%s", line);
317 	}
318 	fprintf(tmp, "%s %s %d\n", e->domain, e->hash, e->verified);
319 
320 	free(line);
321 	err = ferror(tmp);
322 
323 	fclose(tmp);
324 	fclose(f);
325 
326 	if (err) {
327 		unlink(sfn);
328 		return -1;
329 	}
330 
331 	if (rename(sfn, known_hosts_file))
332 		return -1;
333 	return 0;
334 }
335 
336 static size_t
337 join_path(char *buf, const char *lhs, const char *rhs, size_t buflen)
338 {
339 	strlcpy(buf, lhs, buflen);
340 	return strlcat(buf, rhs, buflen);
341 }
342 
343 static void
344 getenv_default(char *buf, const char *name, const char *def, size_t buflen)
345 {
346 	size_t ret;
347 	char *home, *env;
348 
349 	if ((home = getenv("HOME")) == NULL)
350 		errx(1, "HOME is not defined");
351 
352 	if ((env = getenv(name)) != NULL)
353 		ret = strlcpy(buf, env, buflen);
354 	else
355 		ret = join_path(buf, home, def, buflen);
356 
357 	if (ret >= buflen)
358 		errx(1, "buffer too small for %s", name);
359 }
360 
361 static void
362 mkdirs(const char *path, mode_t mode)
363 {
364 	char copy[PATH_MAX+1], orig[PATH_MAX+1], *parent;
365 
366 	strlcpy(copy, path, sizeof(copy));
367 	strlcpy(orig, path, sizeof(orig));
368 	parent = dirname(copy);
369 	if (!strcmp(parent, "/"))
370 		return;
371 	mkdirs(parent, mode);
372 
373 	if (mkdir(orig, mode) != 0) {
374 		if (errno == EEXIST)
375 			return;
376 		err(1, "can't mkdir %s", orig);
377 	}
378 }
379 
380 static void
381 init_paths(void)
382 {
383 	char		 xdg_config_base[PATH_MAX];
384 	char		 xdg_data_base[PATH_MAX];
385 	char		 xdg_cache_base[PATH_MAX];
386 	char		 old_path[PATH_MAX];
387 	char		*home;
388 	struct stat	 info;
389 
390 	/* old path */
391 	if ((home = getenv("HOME")) == NULL)
392 		errx(1, "HOME is not defined");
393 	join_path(old_path, home, "/.telescope", sizeof(old_path));
394 
395 	/* if ~/.telescope exists, use that instead of xdg dirs */
396 	if (stat(old_path, &info) == 0 && S_ISDIR(info.st_mode)) {
397 		join_path(config_path_base, home, "/.telescope",
398 		    sizeof(config_path_base));
399 		join_path(data_path_base, home, "/.telescope",
400 		    sizeof(data_path_base));
401 		join_path(cache_path_base, home, "/.telescope",
402 		    sizeof(cache_path_base));
403 		return;
404 	}
405 
406 	/* xdg paths */
407 	getenv_default(xdg_config_base, "XDG_CONFIG_HOME", "/.config",
408 	    sizeof(xdg_config_base));
409 	getenv_default(xdg_data_base, "XDG_DATA_HOME", "/.local/share",
410 	    sizeof(xdg_data_base));
411 	getenv_default(xdg_cache_base, "XDG_CACHE_HOME", "/.cache",
412 	    sizeof(xdg_cache_base));
413 
414 	join_path(config_path_base, xdg_config_base, "/telescope",
415 	    sizeof(config_path_base));
416 	join_path(data_path_base, xdg_data_base, "/telescope",
417 	    sizeof(data_path_base));
418 	join_path(cache_path_base, xdg_cache_base, "/telescope",
419 	    sizeof(cache_path_base));
420 
421 	mkdirs(xdg_config_base, S_IRWXU);
422 	mkdirs(xdg_data_base, S_IRWXU);
423 	mkdirs(xdg_cache_base, S_IRWXU);
424 
425 	mkdirs(config_path_base, S_IRWXU);
426 	mkdirs(data_path_base, S_IRWXU);
427 	mkdirs(cache_path_base, S_IRWXU);
428 }
429 
430 int
431 fs_init(void)
432 {
433 	init_paths();
434 
435 	join_path(ctlsock_path, cache_path_base, "/ctl",
436 	    sizeof(ctlsock_path));
437 	join_path(config_path, config_path_base, "/config",
438 	    sizeof(config_path));
439 	join_path(lockfile_path, cache_path_base, "/lock",
440 	    sizeof(lockfile_path));
441 	join_path(bookmark_file, data_path_base, "/bookmarks.gmi",
442 	    sizeof(bookmark_file));
443 	join_path(known_hosts_file, data_path_base, "/known_hosts",
444 	    sizeof(known_hosts_file));
445 	join_path(known_hosts_tmp, cache_path_base,
446 	    "/known_hosts.tmp.XXXXXXXXXX", sizeof(known_hosts_tmp));
447 	join_path(session_file, cache_path_base, "/session",
448 	    sizeof(session_file));
449 	join_path(history_file, cache_path_base, "/history",
450 	    sizeof(history_file));
451 	join_path(crashed_file, cache_path_base, "/crashed",
452 	    sizeof(crashed_file));
453 
454 	return 1;
455 }
456 
457 /*
458  * Parse a line of the session file and restores it.  The format is:
459  *
460  *	URL [flags,...] [title]\n
461  */
462 static inline struct tab *
463 parse_session_line(char *line, struct tab **ct)
464 {
465 	struct tab *tab;
466 	char *s, *t, *ap;
467 	const char *uri, *title = "";
468 	int current = 0, killed = 0;
469 	size_t top_line = 0, current_line = 0;
470 
471 	uri = line;
472 	if ((s = strchr(line, ' ')) == NULL)
473 		return NULL;
474 
475 	*s++ = '\0';
476 
477 	if ((t = strchr(s, ' ')) != NULL) {
478 		*t++ = '\0';
479 		title = t;
480 	}
481 
482 	while ((ap = strsep(&s, ",")) != NULL) {
483 		if (!strcmp(ap, "current"))
484 			current = 1;
485 		else if (!strcmp(ap, "killed"))
486 			killed = 1;
487 		else if (has_prefix(ap, "top="))
488 			top_line = strtonum(ap+4, 0, UINT32_MAX, NULL);
489 		else if (has_prefix(ap, "cur="))
490 			current_line = strtonum(ap+4, 0, UINT32_MAX, NULL);
491 	}
492 
493 	if (top_line > current_line) {
494 		top_line = 0;
495 		current_line = 0;
496 	}
497 
498 	if ((tab = new_tab(uri, NULL, NULL)) == NULL)
499 		die();
500 	tab->hist_cur->line_off = top_line;
501 	tab->hist_cur->current_off = current_line;
502 	strlcpy(tab->buffer.page.title, title, sizeof(tab->buffer.page.title));
503 
504 	if (current)
505 		*ct = tab;
506 	else if (killed)
507 		kill_tab(tab, 1);
508 
509 	return tab;
510 }
511 
512 static inline void
513 sendhist(struct tab *tab, const char *uri, int future)
514 {
515 	struct hist *h;
516 
517 	if ((h = calloc(1, sizeof(*h))) == NULL)
518 		die();
519 	strlcpy(h->h, uri, sizeof(h->h));
520 
521 	if (future)
522 		hist_push(&tab->hist, h);
523 	else
524 		hist_add_before(&tab->hist, tab->hist_cur, h);
525 }
526 
527 static void
528 load_last_session(void)
529 {
530 	struct tab	*tab = NULL, *ct = NULL;
531 	FILE		*session;
532 	size_t		 linesize = 0;
533 	ssize_t		 linelen;
534 	int		 future;
535 	char		*nl, *s, *line = NULL;
536 
537 	if ((session = fopen(session_file, "r")) == NULL) {
538 		new_tab("about:new", NULL, NULL);
539 		switch_to_tab(new_tab("about:help", NULL, NULL));
540 		return;
541 	}
542 
543 	while ((linelen = getline(&line, &linesize, session)) != -1) {
544 		if ((nl = strchr(line, '\n')) != NULL)
545 			*nl = '\0';
546 
547 		if (*line == '<' || *line == '>') {
548 			future = *line == '>';
549 			s = line+1;
550 			if (*s != ' ' || tab == NULL)
551 				continue;
552 			sendhist(tab, ++s, future);
553 		} else {
554 			tab = parse_session_line(line, &ct);
555 		}
556 	}
557 
558 	fclose(session);
559 	free(line);
560 
561 	if (ct != NULL)
562 		switch_to_tab(ct);
563 
564 	if (last_time_crashed())
565 		switch_to_tab(new_tab("about:crash", NULL, NULL));
566 }
567 
568 static void
569 load_hist(void)
570 {
571 	FILE		*hist;
572 	size_t		 linesize = 0;
573 	ssize_t		 linelen;
574 	char		*nl, *spc, *line = NULL;
575 	const char	*errstr;
576 	struct histitem	 hi;
577 
578 	if ((hist = fopen(history_file, "r")) == NULL)
579 		return;
580 
581 	while ((linelen = getline(&line, &linesize, hist)) != -1) {
582 		if ((nl = strchr(line, '\n')) != NULL)
583 			*nl = '\0';
584 		if ((spc = strchr(line, ' ')) == NULL)
585 			continue;
586 		*spc = '\0';
587 		spc++;
588 
589 		memset(&hi, 0, sizeof(hi));
590 		hi.ts = strtonum(line, INT64_MIN, INT64_MAX, &errstr);
591 		if (errstr != NULL)
592 			continue;
593 		if (strlcpy(hi.uri, spc, sizeof(hi.uri)) >= sizeof(hi.uri))
594 			continue;
595 
596 		history_push(&hi);
597 	}
598 
599 	fclose(hist);
600 	free(line);
601 
602 	history_sort();
603 }
604 
605 int
606 fs_load_state(struct ohash *certs)
607 {
608 	load_certs(certs);
609 	load_hist();
610 	load_last_session();
611 	return 0;
612 }
613 
614 /*
615  * Check if the last time telescope crashed.  The check is done by
616  * looking at `crashed_file': if it exists then last time we crashed.
617  * Then, while here, touch the file too.  During IMSG_QUIT we'll
618  * remove it.
619  */
620 static int
621 last_time_crashed(void)
622 {
623 	int fd, crashed = 1;
624 
625 	if (safe_mode)
626 		return 0;
627 
628 	if (unlink(crashed_file) == -1 && errno == ENOENT)
629 		crashed = 0;
630 
631 	if ((fd = open(crashed_file, O_CREAT|O_WRONLY, 0600)) == -1)
632 		return crashed;
633 	close(fd);
634 
635 	return crashed;
636 }
637 
638 int
639 lock_session(void)
640 {
641 	struct flock	lock;
642 	int		fd;
643 
644 	if ((fd = open(lockfile_path, O_WRONLY|O_CREAT, 0600)) == -1)
645 		return -1;
646 
647 	lock.l_start = 0;
648 	lock.l_len = 0;
649 	lock.l_type = F_WRLCK;
650 	lock.l_whence = SEEK_SET;
651 
652 	if (fcntl(fd, F_SETLK, &lock) == -1) {
653 		close(fd);
654 		return -1;
655 	}
656 
657 	return fd;
658 }
659 
660 static inline int
661 parse_khost_line(char *line, char *tmp[3])
662 {
663 	char **ap;
664 
665 	for (ap = tmp; ap < &tmp[3] &&
666 	    (*ap = strsep(&line, " \t\n")) != NULL;) {
667 		if (**ap != '\0')
668 			ap++;
669 	}
670 
671 	return ap == &tmp[3] && *line == '\0';
672 }
673 
674 static void
675 load_certs(struct ohash *certs)
676 {
677 	char		*tmp[3], *line = NULL;
678 	const char	*errstr;
679 	size_t		 lineno = 0, linesize = 0;
680 	ssize_t		 linelen;
681 	FILE		*f;
682 	struct tofu_entry *e;
683 
684 	if ((f = fopen(known_hosts_file, "r")) == NULL)
685 		return;
686 
687 	if ((e = calloc(1, sizeof(*e))) == NULL) {
688 		fclose(f);
689 		return;
690 	}
691 
692 	while ((linelen = getline(&line, &linesize, f)) != -1) {
693 		lineno++;
694 
695 		if (parse_khost_line(line, tmp)) {
696 			strlcpy(e->domain, tmp[0], sizeof(e->domain));
697 			strlcpy(e->hash, tmp[1], sizeof(e->hash));
698 
699 			e->verified = strtonum(tmp[2], 0, 1, &errstr);
700 			if (errstr != NULL)
701 				errx(1, "%s:%zu verification for %s is %s: %s",
702 				    known_hosts_file, lineno,
703 				    e->domain, errstr, tmp[2]);
704 
705 			tofu_add(certs, e);
706 		} else {
707 			warnx("%s:%zu invalid entry",
708 			    known_hosts_file, lineno);
709 		}
710 	}
711 
712 	free(line);
713 	fclose(f);
714 	return;
715 }