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