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  * TODO: add some form of locking on the files
21  */
22 
23 #include "compat.h"
24 
25 #include <sys/stat.h>
26 #include <sys/types.h>
27 
28 #include <dirent.h>
29 #include <errno.h>
30 #include <fcntl.h>
31 #include <limits.h>
32 #include <stdio.h>
33 #include <stdlib.h>
34 #include <string.h>
35 #include <unistd.h>
36 
37 #include "telescope.h"
38 #include "pages.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 
58 static struct imsgev		*iev_ui;
59 static FILE			*session;
60 
61 static char	base_path[PATH_MAX];
62 static char	lockfile_path[PATH_MAX];
63 static char	bookmark_file[PATH_MAX];
64 static char	known_hosts_file[PATH_MAX], known_hosts_tmp[PATH_MAX];
65 static char	crashed_file[PATH_MAX];
66 
67 char	session_file[PATH_MAX];
68 
69 static imsg_handlerfn *handlers[] = {
70 	[IMSG_GET] = handle_get,
71 	[IMSG_GET_FILE] = handle_get_file,
72 	[IMSG_QUIT] = handle_quit,
73 	[IMSG_BOOKMARK_PAGE] = handle_bookmark_page,
74 	[IMSG_SAVE_CERT] = handle_save_cert,
75 	[IMSG_UPDATE_CERT] = handle_update_cert,
76 	[IMSG_FILE_OPEN] = handle_file_open,
77 	[IMSG_SESSION_START] = handle_session_start,
78 	[IMSG_SESSION_TAB] = handle_session_tab,
79 	[IMSG_SESSION_TAB_TITLE] = handle_session_tab_title,
80 	[IMSG_SESSION_END] = handle_session_end,
81 };
82 
83 static void __attribute__((__noreturn__))
84 die(void)
85 {
86 	abort(); 		/* TODO */
87 }
88 
89 static void
90 send_file(uint32_t peerid, FILE *f)
91 {
92 	ssize_t	 r;
93 	char	 buf[BUFSIZ];
94 
95 	for (;;) {
96 		r = fread(buf, 1, sizeof(buf), f);
97 		if (r != 0)
98 			fs_send_ui(IMSG_BUF, peerid, -1, buf, r);
99 		if (r != sizeof(buf))
100 			break;
101 	}
102 	fs_send_ui(IMSG_EOF, peerid, -1, NULL, 0);
103 	fclose(f);
104 }
105 
106 static void
107 handle_get(struct imsg *imsg, size_t datalen)
108 {
109 	const char	*bpath = "bookmarks.gmi";
110 	char		 path[PATH_MAX];
111 	FILE		*f;
112 	const char	*data, *p;
113 	size_t		 i;
114 	struct page {
115 		const char	*name;
116 		const char	*path;
117 		const uint8_t	*data;
118 		size_t		 len;
119 	} pages[] = {
120 		{"about",	NULL,	about_about,	about_about_len},
121 		{"blank",	NULL,	about_blank,	about_blank_len},
122 		{"bookmarks",	bpath,	bookmarks,	bookmarks_len},
123 		{"crash",	NULL,	about_crash,	about_crash_len},
124 		{"help",	NULL,	about_help,	about_help_len},
125 		{"license",	NULL,	about_license,	about_license_len},
126 		{"new",		NULL,	about_new,	about_new_len},
127 	}, *page = NULL;
128 
129 	data = imsg->data;
130 	if (data[datalen-1] != '\0') /* make sure it's NUL-terminated */
131 		die();
132 	if ((data = strchr(data, ':')) == NULL)
133 		goto notfound;
134 	data++;
135 
136 	for (i = 0; i < sizeof(pages)/sizeof(pages[0]); ++i)
137 		if (!strcmp(data, pages[i].name)) {
138 			page = &pages[i];
139 			break;
140 		}
141 
142 	if (page == NULL)
143 		goto notfound;
144 
145 	strlcpy(path, base_path, sizeof(path));
146 	strlcat(path, "/", sizeof(path));
147 	if (page->path != NULL)
148 		strlcat(path, page->path, sizeof(path));
149 	else {
150 		strlcat(path, "pages/about_", sizeof(path));
151 		strlcat(path, page->name, sizeof(path));
152 		strlcat(path, ".gmi", sizeof(path));
153 	}
154 
155 	if ((f = fopen(path, "r")) == NULL) {
156 		fs_send_ui(IMSG_BUF, imsg->hdr.peerid, -1,
157 		    page->data, page->len);
158 		fs_send_ui(IMSG_EOF, imsg->hdr.peerid, -1,
159 		    NULL, 0);
160 		return;
161 	}
162 
163 	send_file(imsg->hdr.peerid, f);
164 	return;
165 
166 notfound:
167 	p = "# not found!\n";
168 	fs_send_ui(IMSG_BUF, imsg->hdr.peerid, -1, p, strlen(p));
169 	fs_send_ui(IMSG_EOF, imsg->hdr.peerid, -1, NULL, 0);
170 }
171 
172 static inline void
173 send_hdr(uint32_t peerid, int code, const char *meta)
174 {
175 	fs_send_ui(IMSG_GOT_CODE, peerid, -1, &code, sizeof(code));
176 	fs_send_ui(IMSG_GOT_META, peerid, -1, meta, strlen(meta)+1);
177 }
178 
179 static inline const char *
180 file_type(const char *path)
181 {
182 	struct mapping {
183 		const char	*ext;
184 		const char	*mime;
185 	} ms[] = {
186 		{"diff",	"text/x-patch"},
187 		{"gemini",	"text/gemini"},
188 		{"gmi",		"text/gemini"},
189 		{"markdown",	"text/plain"},
190 		{"md",		"text/plain"},
191 		{"patch",	"text/x-patch"},
192 		{"txt",		"text/plain"},
193 		{NULL, NULL},
194 	}, *m;
195 	char *dot;
196 
197 	if ((dot = strrchr(path, '.')) == NULL)
198 		return NULL;
199 
200 	dot++;
201 
202 	for (m = ms; m->ext != NULL; ++m)
203 		if (!strcmp(m->ext, dot))
204 			return m->mime;
205 
206 	return NULL;
207 }
208 
209 static int
210 select_non_dot(const struct dirent *d)
211 {
212 	return strcmp(d->d_name, ".");
213 }
214 
215 static int
216 select_non_dotdot(const struct dirent *d)
217 {
218 	return strcmp(d->d_name, ".") && strcmp(d->d_name, "..");
219 }
220 
221 static inline void
222 send_dir(uint32_t peerid, const char *path)
223 {
224 	struct dirent	**names;
225 	struct evbuffer	 *ev;
226 	char		 *s;
227 	int		(*selector)(const struct dirent *) = select_non_dot;
228 	int		  i, len;
229 
230 	if (!has_suffix(path, "/")) {
231 		if (asprintf(&s, "%s/", path) == -1)
232 			die();
233 		send_hdr(peerid, 30, s);
234 		free(s);
235 		return;
236 	}
237 
238 	if (!strcmp(path, "/"))
239 		selector = select_non_dotdot;
240 
241 	if ((ev = evbuffer_new()) == NULL ||
242 	    (len = scandir(path, &names, selector, alphasort)) == -1) {
243 		evbuffer_free(ev);
244 		send_hdr(peerid, 40, "failure reading the directory");
245 		return;
246 	}
247 
248 	evbuffer_add_printf(ev, "# Index of %s\n\n", path);
249 	for (i = 0; i < len; ++i) {
250 		evbuffer_add_printf(ev, "=> %s", names[i]->d_name);
251 		if (names[i]->d_type == DT_DIR)
252 			evbuffer_add(ev, "/", 1);
253 		evbuffer_add(ev, "\n", 1);
254 	}
255 
256 	send_hdr(peerid, 20, "text/gemini");
257 	fs_send_ui(IMSG_BUF, peerid, -1,
258 	    EVBUFFER_DATA(ev), EVBUFFER_LENGTH(ev));
259 	fs_send_ui(IMSG_EOF, peerid, -1, NULL, 0);
260 
261 	evbuffer_free(ev);
262 	free(names);
263 }
264 
265 static void
266 handle_get_file(struct imsg *imsg, size_t datalen)
267 {
268 	struct stat	 sb;
269 	FILE		*f;
270 	char		*data;
271 	const char	*meta = NULL;
272 
273 	data = imsg->data;
274 	data[datalen-1] = '\0';
275 
276 	if ((f = fopen(data, "r")) == NULL) {
277 		send_hdr(imsg->hdr.peerid, 51, "can't open the file");
278 		return;
279 	}
280 
281 	if (fstat(fileno(f), &sb) == -1) {
282 		send_hdr(imsg->hdr.peerid, 40, "fstat failed");
283 		return;
284 	}
285 
286 	if (S_ISDIR(sb.st_mode)) {
287 		fclose(f);
288 		send_dir(imsg->hdr.peerid, data);
289 		return;
290 	}
291 
292 	if ((meta = file_type(data)) == NULL) {
293 		fclose(f);
294 		send_hdr(imsg->hdr.peerid, 51,
295 		    "don't know how to visualize this file");
296 		return;
297 	}
298 
299 	send_hdr(imsg->hdr.peerid, 20, meta);
300 	send_file(imsg->hdr.peerid, f);
301 }
302 
303 static void
304 handle_quit(struct imsg *imsg, size_t datalen)
305 {
306 	event_loopbreak();
307 }
308 
309 static void
310 handle_bookmark_page(struct imsg *imsg, size_t datalen)
311 {
312 	char	*data;
313 	int	 res;
314 	FILE	*f;
315 
316 	data = imsg->data;
317 	if (data[datalen-1] != '\0')
318 		die();
319 
320 	if ((f = fopen(bookmark_file, "a")) == NULL) {
321 		res = errno;
322 		goto end;
323 	}
324 	fprintf(f, "=> %s\n", data);
325 	fclose(f);
326 
327 	res = 0;
328 end:
329 	fs_send_ui(IMSG_BOOKMARK_OK, 0, -1, &res, sizeof(res));
330 }
331 
332 static void
333 handle_save_cert(struct imsg *imsg, size_t datalen)
334 {
335 	struct tofu_entry	 e;
336 	FILE			*f;
337 	int			 res;
338 
339 	/* TODO: traverse the file to avoid duplications? */
340 
341 	if (datalen != sizeof(e))
342 		die();
343 	memcpy(&e, imsg->data, datalen);
344 
345 	if ((f = fopen(known_hosts_file, "a")) == NULL) {
346 		res = errno;
347 		goto end;
348 	}
349 	fprintf(f, "%s %s %d\n", e.domain, e.hash, e.verified);
350 	fclose(f);
351 
352 	res = 0;
353 end:
354 	fs_send_ui(IMSG_SAVE_CERT_OK, imsg->hdr.peerid, -1,
355 	    &res, sizeof(res));
356 }
357 
358 static void
359 handle_update_cert(struct imsg *imsg, size_t datalen)
360 {
361 	FILE	*tmp, *f;
362 	struct	 tofu_entry entry;
363 	char	 sfn[PATH_MAX], *line = NULL, *t;
364 	size_t	 l, linesize = 0;
365 	ssize_t	 linelen;
366 	int	 fd, e, res = 0;
367 
368 	if (datalen != sizeof(entry))
369 		die();
370 	memcpy(&entry, imsg->data, datalen);
371 
372 	strlcpy(sfn, known_hosts_tmp, sizeof(sfn));
373 	if ((fd = mkstemp(sfn)) == -1 ||
374 	    (tmp = fdopen(fd, "w")) == NULL) {
375 		if (fd != -1) {
376 			unlink(sfn);
377 			close(fd);
378 		}
379 		res = 0;
380 		goto end;
381 	}
382 
383 	if ((f = fopen(known_hosts_file, "r")) == NULL) {
384 		unlink(sfn);
385 		fclose(tmp);
386                 res = 0;
387 		goto end;
388 	}
389 
390 	l = strlen(entry.domain);
391 	while ((linelen = getline(&line, &linesize, f)) != -1) {
392 		if ((t = strstr(line, entry.domain)) != NULL &&
393 		    (line[l] == ' ' || line[l] == '\t'))
394 			continue;
395 		/* line has a trailing \n */
396 		fprintf(tmp, "%s", line);
397 	}
398 	fprintf(tmp, "%s %s %d\n", entry.domain, entry.hash, entry.verified);
399 
400 	free(line);
401 	e = ferror(tmp);
402 
403 	fclose(tmp);
404 	fclose(f);
405 
406 	if (e) {
407 		unlink(sfn);
408 		res = 0;
409 		goto end;
410 	}
411 
412 	res = rename(sfn, known_hosts_file) != -1;
413 
414 end:
415 	fs_send_ui(IMSG_UPDATE_CERT_OK, imsg->hdr.peerid, -1,
416 	    &res, sizeof(res));
417 }
418 
419 static void
420 handle_file_open(struct imsg *imsg, size_t datalen)
421 {
422 	char	*path, *e;
423 	int	 fd;
424 
425 	path = imsg->data;
426 	if (path[datalen-1] != '\0')
427 		die();
428 
429 	if ((fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, 0644)) == -1) {
430 		e = strerror(errno);
431 		fs_send_ui(IMSG_FILE_OPENED, imsg->hdr.peerid, -1,
432 		    e, strlen(e)+1);
433 	} else
434 		fs_send_ui(IMSG_FILE_OPENED, imsg->hdr.peerid, fd,
435 		    NULL, 0);
436 }
437 
438 static void
439 handle_session_start(struct imsg *imsg, size_t datalen)
440 {
441 	if (datalen != 0)
442 		die();
443 
444 	if ((session = fopen(session_file, "w")) == NULL)
445 		die();
446 }
447 
448 static void
449 handle_session_tab(struct imsg *imsg, size_t datalen)
450 {
451 	char		*url;
452 	uint32_t	 flags;
453 
454 	if (session == NULL)
455 		die();
456 
457 	flags = imsg->hdr.peerid;
458 	url = imsg->data;
459 	if (datalen == 0 || url[datalen-1] != '\0')
460 		die();
461 	fprintf(session, "%s", url);
462 
463 	if (flags & TAB_CURRENT)
464 		fprintf(session, " current ");
465 	else
466 		fprintf(session, " - ");
467 }
468 
469 static void
470 handle_session_tab_title(struct imsg *imsg, size_t datalen)
471 {
472 	const char	*title;
473 
474 	title = imsg->data;
475 	if (title == NULL) {
476 		datalen = 1;
477 		title = "";
478 	}
479 
480 	if (title[datalen-1] != '\0')
481 		die();
482 
483 	fprintf(session, "%s\n", title);
484 }
485 
486 static void
487 handle_session_end(struct imsg *imsg, size_t datalen)
488 {
489 	if (session == NULL)
490 		die();
491 	fclose(session);
492 	session = NULL;
493 }
494 
495 static void
496 handle_dispatch_imsg(int fd, short ev, void *d)
497 {
498 	struct imsgev	*iev = d;
499 	int		 e;
500 
501 	if (dispatch_imsg(iev, ev, handlers, sizeof(handlers)) == -1) {
502 		/*
503 		 * This should leave a ~/.telescope/crashed file to
504 		 * trigger about:crash on next run.  Unfortunately, if
505 		 * the main process dies the fs sticks around and
506 		 * doesn't notice that the fd was closed.  Why EV_READ
507 		 * is not triggered when a fd is closed on the other end?
508 		 */
509 		e = errno;
510 		if ((fd = open(crashed_file, O_CREAT|O_TRUNC|O_WRONLY, 0600))
511 		    == -1)
512 			err(1, "open");
513 		close(fd);
514 		errx(1, "connection closed: %s", strerror(e));
515 	}
516 }
517 
518 static int
519 fs_send_ui(int type, uint32_t peerid, int fd, const void *data,
520     uint16_t datalen)
521 {
522 	return imsg_compose_event(iev_ui, type, peerid, 0, fd,
523 	    data, datalen);
524 }
525 
526 int
527 fs_init(void)
528 {
529 	strlcpy(base_path, getenv("HOME"), sizeof(base_path));
530 	strlcat(base_path, "/.telescope", sizeof(base_path));
531 	mkdir(base_path, 0700);
532 
533 	strlcpy(lockfile_path, base_path, sizeof(lockfile_path));
534 	strlcat(lockfile_path, "/lock", sizeof(lockfile_path));
535 
536 	strlcpy(bookmark_file, base_path, sizeof(bookmark_file));
537 	strlcat(bookmark_file, "/bookmarks.gmi", sizeof(bookmark_file));
538 
539 	strlcpy(known_hosts_file, base_path, sizeof(known_hosts_file));
540 	strlcat(known_hosts_file, "/known_hosts", sizeof(known_hosts_file));
541 
542 	strlcpy(known_hosts_tmp, base_path, sizeof(known_hosts_tmp));
543 	strlcat(known_hosts_tmp, "/known_hosts.tmp.XXXXXXXXXX",
544 	    sizeof(known_hosts_file));
545 
546 	strlcpy(session_file, base_path, sizeof(session_file));
547 	strlcat(session_file, "/session", sizeof(session_file));
548 
549 	strlcpy(crashed_file, base_path, sizeof(crashed_file));
550 	strlcat(crashed_file, "/crashed", sizeof(crashed_file));
551 
552 	return 1;
553 }
554 
555 int
556 fs_main(void)
557 {
558 	setproctitle("fs");
559 
560 	fs_init();
561 
562 	event_init();
563 
564 	/* Setup pipe and event handler to the main process */
565 	if ((iev_ui = malloc(sizeof(*iev_ui))) == NULL)
566 		die();
567 	imsg_init(&iev_ui->ibuf, 3);
568 	iev_ui->handler = handle_dispatch_imsg;
569 	iev_ui->events = EV_READ;
570 	event_set(&iev_ui->ev, iev_ui->ibuf.fd, iev_ui->events,
571 	    iev_ui->handler, iev_ui);
572 	event_add(&iev_ui->ev, NULL);
573 
574 	sandbox_fs_process();
575 
576 	event_dispatch();
577 	return 0;
578 }
579 
580 
581 
582 int
583 last_time_crashed(void)
584 {
585 	int fd;
586 
587 	if ((fd = open(crashed_file, O_RDONLY)) == -1)
588 		return 0;
589 
590 	close(fd);
591 	unlink(crashed_file);
592 	return 1;
593 }
594 
595 int
596 lock_session(void)
597 {
598 	struct flock	lock;
599 	int		fd;
600 
601 	if ((fd = open(lockfile_path, O_WRONLY|O_CREAT, 0600)) == -1)
602 		return -1;
603 
604 	lock.l_start = 0;
605 	lock.l_len = 0;
606 	lock.l_type = F_WRLCK;
607 	lock.l_whence = SEEK_SET;
608 
609 	if (fcntl(fd, F_SETLK, &lock) == -1) {
610 		close(fd);
611 		return -1;
612 	}
613 
614 	return fd;
615 }
616 
617 static int
618 parse_khost_line(char *line, char *tmp[3])
619 {
620 	char **ap;
621 
622 	for (ap = tmp; ap < &tmp[3] &&
623 	    (*ap = strsep(&line, " \t\n")) != NULL;) {
624 		if (**ap != '\0')
625 			ap++;
626 	}
627 
628 	return ap == &tmp[3] && *line == '\0';
629 }
630 
631 int
632 load_certs(struct ohash *h)
633 {
634 	char		*tmp[3], *line = NULL;
635 	const char	*errstr;
636 	size_t		 lineno = 0, linesize = 0;
637 	ssize_t		 linelen;
638 	FILE		*f;
639 	struct tofu_entry *e;
640 
641 	if ((f = fopen(known_hosts_file, "r")) == NULL)
642 		return 0;
643 
644 	while ((linelen = getline(&line, &linesize, f)) != -1) {
645 		if ((e = calloc(1, sizeof(*e))) == NULL)
646 			abort();
647 
648 		lineno++;
649 
650 		if (parse_khost_line(line, tmp)) {
651 			strlcpy(e->domain, tmp[0], sizeof(e->domain));
652 			strlcpy(e->hash, tmp[1], sizeof(e->hash));
653 
654 			e->verified = strtonum(tmp[2], 0, 1, &errstr);
655 			if (errstr != NULL)
656 				errx(1, "%s:%zu verification for %s is %s: %s",
657 				    known_hosts_file, lineno,
658 				    e->domain, errstr, tmp[2]);
659 			tofu_add(h, e);
660 		} else {
661 			warnx("%s:%zu invalid entry",
662 			    known_hosts_file, lineno);
663 			free(e);
664 		}
665 	}
666 
667 	free(line);
668 	return ferror(f);
669 }
670