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 the data in ~/.telescope
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 <stdio.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include <unistd.h>
34 
35 #include "pages.h"
36 #include "telescope.h"
37 
38 static void		 die(void) __attribute__((__noreturn__));
39 static void		 send_file(uint32_t, FILE *);
40 static void		 handle_get(struct imsg*, size_t);
41 static int		 select_non_dot(const struct dirent *);
42 static int		 select_non_dotdot(const struct dirent *);
43 static void		 handle_get_file(struct imsg*, size_t);
44 static void		 handle_quit(struct imsg*, size_t);
45 static void		 handle_bookmark_page(struct imsg*, size_t);
46 static void		 handle_save_cert(struct imsg*, size_t);
47 static void		 handle_update_cert(struct imsg*, size_t);
48 static void		 handle_file_open(struct imsg*, size_t);
49 static void		 handle_session_start(struct imsg*, size_t);
50 static void		 handle_session_tab(struct imsg*, size_t);
51 static void		 handle_session_tab_title(struct imsg*, size_t);
52 static void		 handle_session_end(struct imsg*, size_t);
53 static void		 handle_dispatch_imsg(int, short, void*);
54 static int		 fs_send_ui(int, uint32_t, int, const void *, uint16_t);
55 
56 static struct imsgev		*iev_ui;
57 static FILE			*session;
58 
59 static char	base_path[PATH_MAX];
60 static char	lockfile_path[PATH_MAX];
61 static char	bookmark_file[PATH_MAX];
62 static char	known_hosts_file[PATH_MAX], known_hosts_tmp[PATH_MAX];
63 static char	crashed_file[PATH_MAX];
64 
65 char	session_file[PATH_MAX];
66 
67 static imsg_handlerfn *handlers[] = {
68 	[IMSG_GET] = handle_get,
69 	[IMSG_GET_FILE] = handle_get_file,
70 	[IMSG_QUIT] = handle_quit,
71 	[IMSG_BOOKMARK_PAGE] = handle_bookmark_page,
72 	[IMSG_SAVE_CERT] = handle_save_cert,
73 	[IMSG_UPDATE_CERT] = handle_update_cert,
74 	[IMSG_FILE_OPEN] = handle_file_open,
75 	[IMSG_SESSION_START] = handle_session_start,
76 	[IMSG_SESSION_TAB] = handle_session_tab,
77 	[IMSG_SESSION_TAB_TITLE] = handle_session_tab_title,
78 	[IMSG_SESSION_END] = handle_session_end,
79 };
80 
81 static void __attribute__((__noreturn__))
82 die(void)
83 {
84 	abort(); 		/* TODO */
85 }
86 
87 static void
88 send_file(uint32_t peerid, FILE *f)
89 {
90 	ssize_t	 r;
91 	char	 buf[BUFSIZ];
92 
93 	for (;;) {
94 		r = fread(buf, 1, sizeof(buf), f);
95 		if (r != 0)
96 			fs_send_ui(IMSG_BUF, peerid, -1, buf, r);
97 		if (r != sizeof(buf))
98 			break;
99 	}
100 	fs_send_ui(IMSG_EOF, peerid, -1, NULL, 0);
101 	fclose(f);
102 }
103 
104 static void
105 handle_get(struct imsg *imsg, size_t datalen)
106 {
107 	const char	*bpath = "bookmarks.gmi";
108 	char		 path[PATH_MAX];
109 	FILE		*f;
110 	const char	*data, *p;
111 	size_t		 i;
112 	struct page {
113 		const char	*name;
114 		const char	*path;
115 		const uint8_t	*data;
116 		size_t		 len;
117 	} pages[] = {
118 		{"about",	NULL,	about_about,	about_about_len},
119 		{"blank",	NULL,	about_blank,	about_blank_len},
120 		{"bookmarks",	bpath,	bookmarks,	bookmarks_len},
121 		{"crash",	NULL,	about_crash,	about_crash_len},
122 		{"help",	NULL,	about_help,	about_help_len},
123 		{"license",	NULL,	about_license,	about_license_len},
124 		{"new",		NULL,	about_new,	about_new_len},
125 	}, *page = NULL;
126 
127 	data = imsg->data;
128 	if (data[datalen-1] != '\0') /* make sure it's NUL-terminated */
129 		die();
130 	if ((data = strchr(data, ':')) == NULL)
131 		goto notfound;
132 	data++;
133 
134 	for (i = 0; i < sizeof(pages)/sizeof(pages[0]); ++i)
135 		if (!strcmp(data, pages[i].name)) {
136 			page = &pages[i];
137 			break;
138 		}
139 
140 	if (page == NULL)
141 		goto notfound;
142 
143 	strlcpy(path, base_path, sizeof(path));
144 	strlcat(path, "/", sizeof(path));
145 	if (page->path != NULL)
146 		strlcat(path, page->path, sizeof(path));
147 	else {
148 		strlcat(path, "pages/about_", sizeof(path));
149 		strlcat(path, page->name, sizeof(path));
150 		strlcat(path, ".gmi", sizeof(path));
151 	}
152 
153 	if ((f = fopen(path, "r")) == NULL) {
154 		fs_send_ui(IMSG_BUF, imsg->hdr.peerid, -1,
155 		    page->data, page->len);
156 		fs_send_ui(IMSG_EOF, imsg->hdr.peerid, -1,
157 		    NULL, 0);
158 		return;
159 	}
160 
161 	send_file(imsg->hdr.peerid, f);
162 	return;
163 
164 notfound:
165 	p = "# not found!\n";
166 	fs_send_ui(IMSG_BUF, imsg->hdr.peerid, -1, p, strlen(p));
167 	fs_send_ui(IMSG_EOF, imsg->hdr.peerid, -1, NULL, 0);
168 }
169 
170 static inline void
171 send_hdr(uint32_t peerid, int code, const char *meta)
172 {
173 	fs_send_ui(IMSG_GOT_CODE, peerid, -1, &code, sizeof(code));
174 	fs_send_ui(IMSG_GOT_META, peerid, -1, meta, strlen(meta)+1);
175 }
176 
177 static inline void
178 send_errno(uint32_t peerid, int code, const char *str, int no)
179 {
180 	char *s;
181 
182 	if (asprintf(&s, "%s: %s", str, strerror(no)) == -1)
183 		s = NULL;
184 
185 	send_hdr(peerid, code, s == NULL ? str : s);
186 	free(s);
187 }
188 
189 static inline const char *
190 file_type(const char *path)
191 {
192 	struct mapping {
193 		const char	*ext;
194 		const char	*mime;
195 	} ms[] = {
196 		{"diff",	"text/x-patch"},
197 		{"gemini",	"text/gemini"},
198 		{"gmi",		"text/gemini"},
199 		{"markdown",	"text/plain"},
200 		{"md",		"text/plain"},
201 		{"patch",	"text/x-patch"},
202 		{"txt",		"text/plain"},
203 		{NULL, NULL},
204 	}, *m;
205 	char *dot;
206 
207 	if ((dot = strrchr(path, '.')) == NULL)
208 		return NULL;
209 
210 	dot++;
211 
212 	for (m = ms; m->ext != NULL; ++m)
213 		if (!strcmp(m->ext, dot))
214 			return m->mime;
215 
216 	return NULL;
217 }
218 
219 static int
220 select_non_dot(const struct dirent *d)
221 {
222 	return strcmp(d->d_name, ".");
223 }
224 
225 static int
226 select_non_dotdot(const struct dirent *d)
227 {
228 	return strcmp(d->d_name, ".") && strcmp(d->d_name, "..");
229 }
230 
231 static inline void
232 send_dir(uint32_t peerid, const char *path)
233 {
234 	struct dirent	**names;
235 	struct evbuffer	 *ev;
236 	char		 *s;
237 	int		(*selector)(const struct dirent *) = select_non_dot;
238 	int		  i, len, no;
239 
240 	if (!has_suffix(path, "/")) {
241 		if (asprintf(&s, "%s/", path) == -1)
242 			die();
243 		send_hdr(peerid, 30, s);
244 		free(s);
245 		return;
246 	}
247 
248 	if (!strcmp(path, "/"))
249 		selector = select_non_dotdot;
250 
251 	if ((ev = evbuffer_new()) == NULL ||
252 	    (len = scandir(path, &names, selector, alphasort)) == -1) {
253 		no = errno;
254 		evbuffer_free(ev);
255 		send_errno(peerid, 40, "failure reading the directory", no);
256 		return;
257 	}
258 
259 	evbuffer_add_printf(ev, "# Index of %s\n\n", path);
260 	for (i = 0; i < len; ++i) {
261 		evbuffer_add_printf(ev, "=> %s", names[i]->d_name);
262 		if (names[i]->d_type == DT_DIR)
263 			evbuffer_add(ev, "/", 1);
264 		evbuffer_add(ev, "\n", 1);
265 	}
266 
267 	send_hdr(peerid, 20, "text/gemini");
268 	fs_send_ui(IMSG_BUF, peerid, -1,
269 	    EVBUFFER_DATA(ev), EVBUFFER_LENGTH(ev));
270 	fs_send_ui(IMSG_EOF, peerid, -1, NULL, 0);
271 
272 	evbuffer_free(ev);
273 	free(names);
274 }
275 
276 static void
277 handle_get_file(struct imsg *imsg, size_t datalen)
278 {
279 	struct stat	 sb;
280 	FILE		*f;
281 	char		*data;
282 	const char	*meta = NULL;
283 
284 	data = imsg->data;
285 	data[datalen-1] = '\0';
286 
287 	if ((f = fopen(data, "r")) == NULL) {
288 		send_errno(imsg->hdr.peerid, 51, "can't open", errno);
289 		return;
290 	}
291 
292 	if (fstat(fileno(f), &sb) == -1) {
293 		send_errno(imsg->hdr.peerid, 40, "fstat", errno);
294 		return;
295 	}
296 
297 	if (S_ISDIR(sb.st_mode)) {
298 		fclose(f);
299 		send_dir(imsg->hdr.peerid, data);
300 		return;
301 	}
302 
303 	if ((meta = file_type(data)) == NULL) {
304 		fclose(f);
305 		send_hdr(imsg->hdr.peerid, 51,
306 		    "don't know how to visualize this file");
307 		return;
308 	}
309 
310 	send_hdr(imsg->hdr.peerid, 20, meta);
311 	send_file(imsg->hdr.peerid, f);
312 }
313 
314 static void
315 handle_quit(struct imsg *imsg, size_t datalen)
316 {
317 	if (!safe_mode)
318 		unlink(crashed_file);
319 
320 	event_loopbreak();
321 }
322 
323 static void
324 handle_bookmark_page(struct imsg *imsg, size_t datalen)
325 {
326 	char	*data;
327 	int	 res;
328 	FILE	*f;
329 
330 	data = imsg->data;
331 	if (data[datalen-1] != '\0')
332 		die();
333 
334 	if ((f = fopen(bookmark_file, "a")) == NULL) {
335 		res = errno;
336 		goto end;
337 	}
338 	fprintf(f, "=> %s\n", data);
339 	fclose(f);
340 
341 	res = 0;
342 end:
343 	fs_send_ui(IMSG_BOOKMARK_OK, 0, -1, &res, sizeof(res));
344 }
345 
346 static void
347 handle_save_cert(struct imsg *imsg, size_t datalen)
348 {
349 	struct tofu_entry	 e;
350 	FILE			*f;
351 	int			 res;
352 
353 	/* TODO: traverse the file to avoid duplications? */
354 
355 	if (datalen != sizeof(e))
356 		die();
357 	memcpy(&e, imsg->data, datalen);
358 
359 	if ((f = fopen(known_hosts_file, "a")) == NULL) {
360 		res = errno;
361 		goto end;
362 	}
363 	fprintf(f, "%s %s %d\n", e.domain, e.hash, e.verified);
364 	fclose(f);
365 
366 	res = 0;
367 end:
368 	fs_send_ui(IMSG_SAVE_CERT_OK, imsg->hdr.peerid, -1,
369 	    &res, sizeof(res));
370 }
371 
372 static void
373 handle_update_cert(struct imsg *imsg, size_t datalen)
374 {
375 	FILE	*tmp, *f;
376 	struct	 tofu_entry entry;
377 	char	 sfn[PATH_MAX], *line = NULL, *t;
378 	size_t	 l, linesize = 0;
379 	ssize_t	 linelen;
380 	int	 fd, e, res = 0;
381 
382 	if (datalen != sizeof(entry))
383 		die();
384 	memcpy(&entry, imsg->data, datalen);
385 
386 	strlcpy(sfn, known_hosts_tmp, sizeof(sfn));
387 	if ((fd = mkstemp(sfn)) == -1 ||
388 	    (tmp = fdopen(fd, "w")) == NULL) {
389 		if (fd != -1) {
390 			unlink(sfn);
391 			close(fd);
392 		}
393 		res = 0;
394 		goto end;
395 	}
396 
397 	if ((f = fopen(known_hosts_file, "r")) == NULL) {
398 		unlink(sfn);
399 		fclose(tmp);
400                 res = 0;
401 		goto end;
402 	}
403 
404 	l = strlen(entry.domain);
405 	while ((linelen = getline(&line, &linesize, f)) != -1) {
406 		if ((t = strstr(line, entry.domain)) != NULL &&
407 		    (line[l] == ' ' || line[l] == '\t'))
408 			continue;
409 		/* line has a trailing \n */
410 		fprintf(tmp, "%s", line);
411 	}
412 	fprintf(tmp, "%s %s %d\n", entry.domain, entry.hash, entry.verified);
413 
414 	free(line);
415 	e = ferror(tmp);
416 
417 	fclose(tmp);
418 	fclose(f);
419 
420 	if (e) {
421 		unlink(sfn);
422 		res = 0;
423 		goto end;
424 	}
425 
426 	res = rename(sfn, known_hosts_file) != -1;
427 
428 end:
429 	fs_send_ui(IMSG_UPDATE_CERT_OK, imsg->hdr.peerid, -1,
430 	    &res, sizeof(res));
431 }
432 
433 static void
434 handle_file_open(struct imsg *imsg, size_t datalen)
435 {
436 	char	*path, *e;
437 	int	 fd;
438 
439 	path = imsg->data;
440 	if (path[datalen-1] != '\0')
441 		die();
442 
443 	if ((fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, 0644)) == -1) {
444 		e = strerror(errno);
445 		fs_send_ui(IMSG_FILE_OPENED, imsg->hdr.peerid, -1,
446 		    e, strlen(e)+1);
447 	} else
448 		fs_send_ui(IMSG_FILE_OPENED, imsg->hdr.peerid, fd,
449 		    NULL, 0);
450 }
451 
452 static void
453 handle_session_start(struct imsg *imsg, size_t datalen)
454 {
455 	if (datalen != 0)
456 		die();
457 
458 	if ((session = fopen(session_file, "w")) == NULL)
459 		die();
460 }
461 
462 static void
463 handle_session_tab(struct imsg *imsg, size_t datalen)
464 {
465 	char		*url;
466 	uint32_t	 flags;
467 
468 	if (session == NULL)
469 		die();
470 
471 	flags = imsg->hdr.peerid;
472 	url = imsg->data;
473 	if (datalen == 0 || url[datalen-1] != '\0')
474 		die();
475 	fprintf(session, "%s", url);
476 
477 	if (flags & TAB_CURRENT)
478 		fprintf(session, " current ");
479 	else
480 		fprintf(session, " - ");
481 }
482 
483 static void
484 handle_session_tab_title(struct imsg *imsg, size_t datalen)
485 {
486 	const char	*title;
487 
488 	title = imsg->data;
489 	if (title == NULL) {
490 		datalen = 1;
491 		title = "";
492 	}
493 
494 	if (title[datalen-1] != '\0')
495 		die();
496 
497 	fprintf(session, "%s\n", title);
498 }
499 
500 static void
501 handle_session_end(struct imsg *imsg, size_t datalen)
502 {
503 	if (session == NULL)
504 		die();
505 	fclose(session);
506 	session = NULL;
507 }
508 
509 static void
510 handle_dispatch_imsg(int fd, short ev, void *d)
511 {
512 	struct imsgev	*iev = d;
513 	int		 e;
514 
515 	if (dispatch_imsg(iev, ev, handlers, sizeof(handlers)) == -1) {
516 		/*
517 		 * This should leave a ~/.telescope/crashed file to
518 		 * trigger about:crash on next run.  Unfortunately, if
519 		 * the main process dies the fs sticks around and
520 		 * doesn't notice that the fd was closed.  Why EV_READ
521 		 * is not triggered when a fd is closed on the other end?
522 		 */
523 		e = errno;
524 		if ((fd = open(crashed_file, O_CREAT|O_TRUNC|O_WRONLY, 0600))
525 		    == -1)
526 			err(1, "open");
527 		close(fd);
528 		errx(1, "connection closed: %s", strerror(e));
529 	}
530 }
531 
532 static int
533 fs_send_ui(int type, uint32_t peerid, int fd, const void *data,
534     uint16_t datalen)
535 {
536 	return imsg_compose_event(iev_ui, type, peerid, 0, fd,
537 	    data, datalen);
538 }
539 
540 int
541 fs_init(void)
542 {
543 	strlcpy(base_path, getenv("HOME"), sizeof(base_path));
544 	strlcat(base_path, "/.telescope", sizeof(base_path));
545 	mkdir(base_path, 0700);
546 
547 	strlcpy(lockfile_path, base_path, sizeof(lockfile_path));
548 	strlcat(lockfile_path, "/lock", sizeof(lockfile_path));
549 
550 	strlcpy(bookmark_file, base_path, sizeof(bookmark_file));
551 	strlcat(bookmark_file, "/bookmarks.gmi", sizeof(bookmark_file));
552 
553 	strlcpy(known_hosts_file, base_path, sizeof(known_hosts_file));
554 	strlcat(known_hosts_file, "/known_hosts", sizeof(known_hosts_file));
555 
556 	strlcpy(known_hosts_tmp, base_path, sizeof(known_hosts_tmp));
557 	strlcat(known_hosts_tmp, "/known_hosts.tmp.XXXXXXXXXX",
558 	    sizeof(known_hosts_file));
559 
560 	strlcpy(session_file, base_path, sizeof(session_file));
561 	strlcat(session_file, "/session", sizeof(session_file));
562 
563 	strlcpy(crashed_file, base_path, sizeof(crashed_file));
564 	strlcat(crashed_file, "/crashed", sizeof(crashed_file));
565 
566 	return 1;
567 }
568 
569 int
570 fs_main(void)
571 {
572 	setproctitle("fs");
573 
574 	fs_init();
575 
576 	event_init();
577 
578 	/* Setup pipe and event handler to the main process */
579 	if ((iev_ui = malloc(sizeof(*iev_ui))) == NULL)
580 		die();
581 	imsg_init(&iev_ui->ibuf, 3);
582 	iev_ui->handler = handle_dispatch_imsg;
583 	iev_ui->events = EV_READ;
584 	event_set(&iev_ui->ev, iev_ui->ibuf.fd, iev_ui->events,
585 	    iev_ui->handler, iev_ui);
586 	event_add(&iev_ui->ev, NULL);
587 
588 	sandbox_fs_process();
589 
590 	event_dispatch();
591 	return 0;
592 }
593 
594 
595 
596 /*
597  * Check if the last time telescope crashed.  The check is done by
598  * looking at `crashed_file': if it exists then last time we crashed.
599  * Then, while here, touch the file too.  During IMSG_QUIT we'll
600  * remove it.
601  */
602 int
603 last_time_crashed(void)
604 {
605 	int fd, crashed = 1;
606 
607 	if (safe_mode)
608 		return 0;
609 
610 	if (unlink(crashed_file) == -1 && errno == ENOENT)
611 		crashed = 0;
612 
613 	if ((fd = open(crashed_file, O_CREAT|O_WRONLY, 0600)) == -1)
614 		return crashed;
615 	close(fd);
616 
617 	return crashed;
618 }
619 
620 int
621 lock_session(void)
622 {
623 	struct flock	lock;
624 	int		fd;
625 
626 	if ((fd = open(lockfile_path, O_WRONLY|O_CREAT, 0600)) == -1)
627 		return -1;
628 
629 	lock.l_start = 0;
630 	lock.l_len = 0;
631 	lock.l_type = F_WRLCK;
632 	lock.l_whence = SEEK_SET;
633 
634 	if (fcntl(fd, F_SETLK, &lock) == -1) {
635 		close(fd);
636 		return -1;
637 	}
638 
639 	return fd;
640 }
641 
642 static int
643 parse_khost_line(char *line, char *tmp[3])
644 {
645 	char **ap;
646 
647 	for (ap = tmp; ap < &tmp[3] &&
648 	    (*ap = strsep(&line, " \t\n")) != NULL;) {
649 		if (**ap != '\0')
650 			ap++;
651 	}
652 
653 	return ap == &tmp[3] && *line == '\0';
654 }
655 
656 int
657 load_certs(struct ohash *h)
658 {
659 	char		*tmp[3], *line = NULL;
660 	const char	*errstr;
661 	size_t		 lineno = 0, linesize = 0;
662 	ssize_t		 linelen;
663 	FILE		*f;
664 	struct tofu_entry *e;
665 
666 	if ((f = fopen(known_hosts_file, "r")) == NULL)
667 		return 0;
668 
669 	while ((linelen = getline(&line, &linesize, f)) != -1) {
670 		if ((e = calloc(1, sizeof(*e))) == NULL)
671 			abort();
672 
673 		lineno++;
674 
675 		if (parse_khost_line(line, tmp)) {
676 			strlcpy(e->domain, tmp[0], sizeof(e->domain));
677 			strlcpy(e->hash, tmp[1], sizeof(e->hash));
678 
679 			e->verified = strtonum(tmp[2], 0, 1, &errstr);
680 			if (errstr != NULL)
681 				errx(1, "%s:%zu verification for %s is %s: %s",
682 				    known_hosts_file, lineno,
683 				    e->domain, errstr, tmp[2]);
684 			tofu_add(h, e);
685 		} else {
686 			warnx("%s:%zu invalid entry",
687 			    known_hosts_file, lineno);
688 			free(e);
689 		}
690 	}
691 
692 	free(line);
693 	return ferror(f);
694 }
695