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 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 const char *
178 file_type(const char *path)
179 {
180 	struct mapping {
181 		const char	*ext;
182 		const char	*mime;
183 	} ms[] = {
184 		{"diff",	"text/x-patch"},
185 		{"gemini",	"text/gemini"},
186 		{"gmi",		"text/gemini"},
187 		{"markdown",	"text/plain"},
188 		{"md",		"text/plain"},
189 		{"patch",	"text/x-patch"},
190 		{"txt",		"text/plain"},
191 		{NULL, NULL},
192 	}, *m;
193 	char *dot;
194 
195 	if ((dot = strrchr(path, '.')) == NULL)
196 		return NULL;
197 
198 	dot++;
199 
200 	for (m = ms; m->ext != NULL; ++m)
201 		if (!strcmp(m->ext, dot))
202 			return m->mime;
203 
204 	return NULL;
205 }
206 
207 static inline void
208 send_dir(uint32_t peerid, const char *path)
209 {
210 	struct dirent	**names;
211 	struct evbuffer	 *ev;
212 	int		  i, len;
213 
214 	if ((ev = evbuffer_new()) == NULL ||
215 	    (len = scandir(path, &names, NULL, alphasort)) == -1) {
216 		evbuffer_free(ev);
217 		send_hdr(peerid, 40, "failure reading the directory");
218 		return;
219 	}
220 
221 	evbuffer_add_printf(ev, "# Index of %s\n\n", path);
222 	for (i = 0; i < len; ++i) {
223 		evbuffer_add_printf(ev, "=> %s", names[i]->d_name);
224 		if (names[i]->d_type == DT_DIR)
225 			evbuffer_add(ev, "/", 1);
226 		evbuffer_add(ev, "\n", 1);
227 	}
228 
229 	send_hdr(peerid, 20, "text/gemini");
230 	fs_send_ui(IMSG_BUF, peerid, -1,
231 	    EVBUFFER_DATA(ev), EVBUFFER_LENGTH(ev));
232 	fs_send_ui(IMSG_EOF, peerid, -1, NULL, 0);
233 
234 	evbuffer_free(ev);
235 	free(names);
236 }
237 
238 static void
239 handle_get_file(struct imsg *imsg, size_t datalen)
240 {
241 	struct stat	 sb;
242 	FILE		*f;
243 	char		*data;
244 	const char	*meta = NULL;
245 
246 	data = imsg->data;
247 	data[datalen-1] = '\0';
248 
249 	if ((f = fopen(data, "r")) == NULL) {
250 		send_hdr(imsg->hdr.peerid, 51, "can't open the file");
251 		return;
252 	}
253 
254 	if (fstat(fileno(f), &sb) == -1) {
255 		send_hdr(imsg->hdr.peerid, 40, "fstat failed");
256 		return;
257 	}
258 
259 	if (S_ISDIR(sb.st_mode)) {
260 		fclose(f);
261 		send_dir(imsg->hdr.peerid, data);
262 		return;
263 	}
264 
265 	if ((meta = file_type(data)) == NULL) {
266 		fclose(f);
267 		send_hdr(imsg->hdr.peerid, 51,
268 		    "don't know how to visualize this file");
269 		return;
270 	}
271 
272 	send_hdr(imsg->hdr.peerid, 20, meta);
273 	send_file(imsg->hdr.peerid, f);
274 }
275 
276 static void
277 handle_quit(struct imsg *imsg, size_t datalen)
278 {
279 	event_loopbreak();
280 }
281 
282 static void
283 handle_bookmark_page(struct imsg *imsg, size_t datalen)
284 {
285 	char	*data;
286 	int	 res;
287 	FILE	*f;
288 
289 	data = imsg->data;
290 	if (data[datalen-1] != '\0')
291 		die();
292 
293 	if ((f = fopen(bookmark_file, "a")) == NULL) {
294 		res = errno;
295 		goto end;
296 	}
297 	fprintf(f, "=> %s\n", data);
298 	fclose(f);
299 
300 	res = 0;
301 end:
302 	fs_send_ui(IMSG_BOOKMARK_OK, 0, -1, &res, sizeof(res));
303 }
304 
305 static void
306 handle_save_cert(struct imsg *imsg, size_t datalen)
307 {
308 	struct tofu_entry	 e;
309 	FILE			*f;
310 	int			 res;
311 
312 	/* TODO: traverse the file to avoid duplications? */
313 
314 	if (datalen != sizeof(e))
315 		die();
316 	memcpy(&e, imsg->data, datalen);
317 
318 	if ((f = fopen(known_hosts_file, "a")) == NULL) {
319 		res = errno;
320 		goto end;
321 	}
322 	fprintf(f, "%s %s %d\n", e.domain, e.hash, e.verified);
323 	fclose(f);
324 
325 	res = 0;
326 end:
327 	fs_send_ui(IMSG_SAVE_CERT_OK, imsg->hdr.peerid, -1,
328 	    &res, sizeof(res));
329 }
330 
331 static void
332 handle_update_cert(struct imsg *imsg, size_t datalen)
333 {
334 	FILE	*tmp, *f;
335 	struct	 tofu_entry entry;
336 	char	 sfn[PATH_MAX], *line = NULL, *t;
337 	size_t	 l, linesize = 0;
338 	ssize_t	 linelen;
339 	int	 fd, e, res = 0;
340 
341 	if (datalen != sizeof(entry))
342 		die();
343 	memcpy(&entry, imsg->data, datalen);
344 
345 	strlcpy(sfn, known_hosts_tmp, sizeof(sfn));
346 	if ((fd = mkstemp(sfn)) == -1 ||
347 	    (tmp = fdopen(fd, "w")) == NULL) {
348 		if (fd != -1) {
349 			unlink(sfn);
350 			close(fd);
351 		}
352 		res = 0;
353 		goto end;
354 	}
355 
356 	if ((f = fopen(known_hosts_file, "r")) == NULL) {
357 		unlink(sfn);
358 		fclose(tmp);
359                 res = 0;
360 		goto end;
361 	}
362 
363 	l = strlen(entry.domain);
364 	while ((linelen = getline(&line, &linesize, f)) != -1) {
365 		if ((t = strstr(line, entry.domain)) != NULL &&
366 		    (line[l] == ' ' || line[l] == '\t'))
367 			continue;
368 		/* line has a trailing \n */
369 		fprintf(tmp, "%s", line);
370 	}
371 	fprintf(tmp, "%s %s %d\n", entry.domain, entry.hash, entry.verified);
372 
373 	free(line);
374 	e = ferror(tmp);
375 
376 	fclose(tmp);
377 	fclose(f);
378 
379 	if (e) {
380 		unlink(sfn);
381 		res = 0;
382 		goto end;
383 	}
384 
385 	res = rename(sfn, known_hosts_file) != -1;
386 
387 end:
388 	fs_send_ui(IMSG_UPDATE_CERT_OK, imsg->hdr.peerid, -1,
389 	    &res, sizeof(res));
390 }
391 
392 static void
393 handle_file_open(struct imsg *imsg, size_t datalen)
394 {
395 	char	*path, *e;
396 	int	 fd;
397 
398 	path = imsg->data;
399 	if (path[datalen-1] != '\0')
400 		die();
401 
402 	if ((fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, 0644)) == -1) {
403 		e = strerror(errno);
404 		fs_send_ui(IMSG_FILE_OPENED, imsg->hdr.peerid, -1,
405 		    e, strlen(e)+1);
406 	} else
407 		fs_send_ui(IMSG_FILE_OPENED, imsg->hdr.peerid, fd,
408 		    NULL, 0);
409 }
410 
411 static void
412 handle_session_start(struct imsg *imsg, size_t datalen)
413 {
414 	if (datalen != 0)
415 		die();
416 
417 	if ((session = fopen(session_file, "w")) == NULL)
418 		die();
419 }
420 
421 static void
422 handle_session_tab(struct imsg *imsg, size_t datalen)
423 {
424 	char		*url;
425 	uint32_t	 flags;
426 
427 	if (session == NULL)
428 		die();
429 
430 	flags = imsg->hdr.peerid;
431 	url = imsg->data;
432 	if (datalen == 0 || url[datalen-1] != '\0')
433 		die();
434 	fprintf(session, "%s", url);
435 
436 	if (flags & TAB_CURRENT)
437 		fprintf(session, " current ");
438 	else
439 		fprintf(session, " - ");
440 }
441 
442 static void
443 handle_session_tab_title(struct imsg *imsg, size_t datalen)
444 {
445 	const char	*title;
446 
447 	title = imsg->data;
448 	if (title == NULL) {
449 		datalen = 1;
450 		title = "";
451 	}
452 
453 	if (title[datalen-1] != '\0')
454 		die();
455 
456 	fprintf(session, "%s\n", title);
457 }
458 
459 static void
460 handle_session_end(struct imsg *imsg, size_t datalen)
461 {
462 	if (session == NULL)
463 		die();
464 	fclose(session);
465 	session = NULL;
466 }
467 
468 static void
469 handle_dispatch_imsg(int fd, short ev, void *d)
470 {
471 	struct imsgev	*iev = d;
472 	int		 e;
473 
474 	if (dispatch_imsg(iev, ev, handlers, sizeof(handlers)) == -1) {
475 		/*
476 		 * This should leave a ~/.telescope/crashed file to
477 		 * trigger about:crash on next run.  Unfortunately, if
478 		 * the main process dies the fs sticks around and
479 		 * doesn't notice that the fd was closed.  Why EV_READ
480 		 * is not triggered when a fd is closed on the other end?
481 		 */
482 		e = errno;
483 		if ((fd = open(crashed_file, O_CREAT|O_TRUNC|O_WRONLY, 0600))
484 		    == -1)
485 			err(1, "open");
486 		close(fd);
487 		errx(1, "connection closed: %s", strerror(e));
488 	}
489 }
490 
491 static int
492 fs_send_ui(int type, uint32_t peerid, int fd, const void *data,
493     uint16_t datalen)
494 {
495 	return imsg_compose_event(iev_ui, type, peerid, 0, fd,
496 	    data, datalen);
497 }
498 
499 int
500 fs_init(void)
501 {
502 	strlcpy(base_path, getenv("HOME"), sizeof(base_path));
503 	strlcat(base_path, "/.telescope", sizeof(base_path));
504 	mkdir(base_path, 0700);
505 
506 	strlcpy(lockfile_path, base_path, sizeof(lockfile_path));
507 	strlcat(lockfile_path, "/lock", sizeof(lockfile_path));
508 
509 	strlcpy(bookmark_file, base_path, sizeof(bookmark_file));
510 	strlcat(bookmark_file, "/bookmarks.gmi", sizeof(bookmark_file));
511 
512 	strlcpy(known_hosts_file, base_path, sizeof(known_hosts_file));
513 	strlcat(known_hosts_file, "/known_hosts", sizeof(known_hosts_file));
514 
515 	strlcpy(known_hosts_tmp, base_path, sizeof(known_hosts_tmp));
516 	strlcat(known_hosts_tmp, "/known_hosts.tmp.XXXXXXXXXX",
517 	    sizeof(known_hosts_file));
518 
519 	strlcpy(session_file, base_path, sizeof(session_file));
520 	strlcat(session_file, "/session", sizeof(session_file));
521 
522 	strlcpy(crashed_file, base_path, sizeof(crashed_file));
523 	strlcat(crashed_file, "/crashed", sizeof(crashed_file));
524 
525 	return 1;
526 }
527 
528 int
529 fs_main(void)
530 {
531 	setproctitle("fs");
532 
533 	fs_init();
534 
535 	event_init();
536 
537 	/* Setup pipe and event handler to the main process */
538 	if ((iev_ui = malloc(sizeof(*iev_ui))) == NULL)
539 		die();
540 	imsg_init(&iev_ui->ibuf, 3);
541 	iev_ui->handler = handle_dispatch_imsg;
542 	iev_ui->events = EV_READ;
543 	event_set(&iev_ui->ev, iev_ui->ibuf.fd, iev_ui->events,
544 	    iev_ui->handler, iev_ui);
545 	event_add(&iev_ui->ev, NULL);
546 
547 	sandbox_fs_process();
548 
549 	event_dispatch();
550 	return 0;
551 }
552 
553 
554 
555 int
556 last_time_crashed(void)
557 {
558 	int fd;
559 
560 	if ((fd = open(crashed_file, O_RDONLY)) == -1)
561 		return 0;
562 
563 	close(fd);
564 	unlink(crashed_file);
565 	return 1;
566 }
567 
568 int
569 lock_session(void)
570 {
571 	struct flock	lock;
572 	int		fd;
573 
574 	if ((fd = open(lockfile_path, O_WRONLY|O_CREAT, 0600)) == -1)
575 		return -1;
576 
577 	lock.l_start = 0;
578 	lock.l_len = 0;
579 	lock.l_type = F_WRLCK;
580 	lock.l_whence = SEEK_SET;
581 
582 	if (fcntl(fd, F_SETLK, &lock) == -1) {
583 		close(fd);
584 		return -1;
585 	}
586 
587 	return fd;
588 }
589 
590 static int
591 parse_khost_line(char *line, char *tmp[3])
592 {
593 	char **ap;
594 
595 	for (ap = tmp; ap < &tmp[3] &&
596 	    (*ap = strsep(&line, " \t\n")) != NULL;) {
597 		if (**ap != '\0')
598 			ap++;
599 	}
600 
601 	return ap == &tmp[3] && *line == '\0';
602 }
603 
604 int
605 load_certs(struct ohash *h)
606 {
607 	char		*tmp[3], *line = NULL;
608 	const char	*errstr;
609 	size_t		 lineno = 0, linesize = 0;
610 	ssize_t		 linelen;
611 	FILE		*f;
612 	struct tofu_entry *e;
613 
614 	if ((f = fopen(known_hosts_file, "r")) == NULL)
615 		return 0;
616 
617 	while ((linelen = getline(&line, &linesize, f)) != -1) {
618 		if ((e = calloc(1, sizeof(*e))) == NULL)
619 			abort();
620 
621 		lineno++;
622 
623 		if (parse_khost_line(line, tmp)) {
624 			strlcpy(e->domain, tmp[0], sizeof(e->domain));
625 			strlcpy(e->hash, tmp[1], sizeof(e->hash));
626 
627 			e->verified = strtonum(tmp[2], 0, 1, &errstr);
628 			if (errstr != NULL)
629 				errx(1, "%s:%zu verification for %s is %s: %s",
630 				    known_hosts_file, lineno,
631 				    e->domain, errstr, tmp[2]);
632 			tofu_add(h, e);
633 		} else {
634 			warnx("%s:%zu invalid entry",
635 			    known_hosts_file, lineno);
636 			free(e);
637 		}
638 	}
639 
640 	free(line);
641 	return ferror(f);
642 }
643