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 <sys/stat.h>
24 
25 #include <errno.h>
26 #include <fcntl.h>
27 #include <limits.h>
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <unistd.h>
32 
33 #include "telescope.h"
34 #include "pages.h"
35 
36 static void		 die(void) __attribute__((__noreturn__));
37 static void		 serve_bookmarks(uint32_t);
38 static void		 send_page(struct imsg *, const char *);
39 static void		 handle_get(struct imsg*, size_t);
40 static void		 handle_quit(struct imsg*, size_t);
41 static void		 handle_bookmark_page(struct imsg*, size_t);
42 static void		 handle_save_cert(struct imsg*, size_t);
43 static void		 handle_update_cert(struct imsg*, size_t);
44 static void		 handle_file_open(struct imsg*, size_t);
45 static void		 handle_session_start(struct imsg*, size_t);
46 static void		 handle_session_tab(struct imsg*, size_t);
47 static void		 handle_session_end(struct imsg*, size_t);
48 static void		 handle_dispatch_imsg(int, short, void*);
49 static int		 fs_send_ui(int, uint32_t, int, const void *, uint16_t);
50 
51 static struct imsgev		*iev_ui;
52 static FILE			*session;
53 
54 static char	lockfile_path[PATH_MAX];
55 static char	bookmark_file[PATH_MAX];
56 static char	known_hosts_file[PATH_MAX], known_hosts_tmp[PATH_MAX];
57 static char	session_file[PATH_MAX];
58 
59 static imsg_handlerfn *handlers[] = {
60 	[IMSG_GET] = handle_get,
61 	[IMSG_QUIT] = handle_quit,
62 	[IMSG_BOOKMARK_PAGE] = handle_bookmark_page,
63 	[IMSG_SAVE_CERT] = handle_save_cert,
64 	[IMSG_UPDATE_CERT] = handle_update_cert,
65 	[IMSG_FILE_OPEN] = handle_file_open,
66 	[IMSG_SESSION_START] = handle_session_start,
67 	[IMSG_SESSION_TAB] = handle_session_tab,
68 	[IMSG_SESSION_END] = handle_session_end,
69 };
70 
71 static void __attribute__((__noreturn__))
72 die(void)
73 {
74 	abort(); 		/* TODO */
75 }
76 
77 static void
78 serve_bookmarks(uint32_t peerid)
79 {
80 	const char	*t;
81 	char		 buf[BUFSIZ];
82 	size_t		 r;
83 	FILE		*f;
84 
85 	if ((f = fopen(bookmark_file, "r")) == NULL) {
86 		t = "# Bookmarks\n\n"
87 		    "No bookmarks yet!\n"
88 		    "Create ~/.telescope/bookmarks.gmi or use `bookmark-page'.\n";
89 		fs_send_ui(IMSG_BUF, peerid, -1, t, strlen(t));
90 		fs_send_ui(IMSG_EOF, peerid, -1, NULL, 0);
91 		return;
92 	}
93 
94 	for (;;) {
95 		r = fread(buf, 1, sizeof(buf), f);
96 		fs_send_ui(IMSG_BUF, peerid, -1, buf, r);
97 		if (r != sizeof(buf))
98 			break;
99 	}
100 
101 	fs_send_ui(IMSG_EOF, peerid, -1, NULL, 0);
102 
103 	fclose(f);
104 }
105 
106 static void
107 send_page(struct imsg *imsg, const char *page)
108 {
109 	fs_send_ui(IMSG_BUF, imsg->hdr.peerid, -1, page, strlen(page));
110 	fs_send_ui(IMSG_EOF, imsg->hdr.peerid, -1, NULL, 0);
111 }
112 
113 static void
114 handle_get(struct imsg *imsg, size_t datalen)
115 {
116 	char		*data;
117 	const char	*p;
118 
119 	data = imsg->data;
120 
121 	if (data[datalen-1] != '\0')
122 		die();
123 
124 	if (!strcmp(data, "about:about")) {
125 		send_page(imsg, about_about);
126 	} else if (!strcmp(data, "about:blank")) {
127 		send_page(imsg, about_blank);
128 	} else if (!strcmp(data, "about:bookmarks")) {
129 		serve_bookmarks(imsg->hdr.peerid);
130 	} else if (!strcmp(data, "about:help")) {
131 		send_page(imsg, about_help);
132 	} else if (!strcmp(data, "about:new")) {
133 		send_page(imsg, about_new);
134 	} else {
135 		p = "# not found!\n";
136 		fs_send_ui(IMSG_BUF, imsg->hdr.peerid, -1, p, strlen(p));
137 		fs_send_ui(IMSG_EOF, imsg->hdr.peerid, -1, NULL, 0);
138 	}
139 }
140 
141 static void
142 handle_quit(struct imsg *imsg, size_t datalen)
143 {
144 	event_loopbreak();
145 }
146 
147 static void
148 handle_bookmark_page(struct imsg *imsg, size_t datalen)
149 {
150 	char	*data;
151 	int	 res;
152 	FILE	*f;
153 
154 	data = imsg->data;
155 	if (data[datalen-1] != '\0')
156 		die();
157 
158 	if ((f = fopen(bookmark_file, "a")) == NULL) {
159 		res = errno;
160 		goto end;
161 	}
162 	fprintf(f, "=> %s\n", data);
163 	fclose(f);
164 
165 	res = 0;
166 end:
167 	fs_send_ui(IMSG_BOOKMARK_OK, 0, -1, &res, sizeof(res));
168 }
169 
170 static void
171 handle_save_cert(struct imsg *imsg, size_t datalen)
172 {
173 	struct tofu_entry	 e;
174 	FILE			*f;
175 	int			 res;
176 
177 	/* TODO: traverse the file to avoid duplications? */
178 
179 	if (datalen != sizeof(e))
180 		die();
181 	memcpy(&e, imsg->data, datalen);
182 
183 	if ((f = fopen(known_hosts_file, "a")) == NULL) {
184 		res = errno;
185 		goto end;
186 	}
187 	fprintf(f, "%s %s %d\n", e.domain, e.hash, e.verified);
188 	fclose(f);
189 
190 	res = 0;
191 end:
192 	fs_send_ui(IMSG_SAVE_CERT_OK, imsg->hdr.peerid, -1,
193 	    &res, sizeof(res));
194 }
195 
196 static void
197 handle_update_cert(struct imsg *imsg, size_t datalen)
198 {
199 	FILE	*tmp, *f;
200 	struct	 tofu_entry entry;
201 	char	 sfn[PATH_MAX], *line = NULL, *t;
202 	size_t	 l, linesize = 0;
203 	ssize_t	 linelen;
204 	int	 fd, e, res = 0;
205 
206 	if (datalen != sizeof(entry))
207 		die();
208 	memcpy(&entry, imsg->data, datalen);
209 
210 	strlcpy(sfn, known_hosts_tmp, sizeof(sfn));
211 	if ((fd = mkstemp(sfn)) == -1 ||
212 	    (tmp = fdopen(fd, "w")) == NULL) {
213 		if (fd != -1) {
214 			unlink(sfn);
215 			close(fd);
216 		}
217 		res = 0;
218 		goto end;
219 	}
220 
221 	if ((f = fopen(known_hosts_file, "r")) == NULL) {
222 		unlink(sfn);
223 		fclose(tmp);
224                 res = 0;
225 		goto end;
226 	}
227 
228 	l = strlen(entry.domain);
229 	while ((linelen = getline(&line, &linesize, f)) != -1) {
230 		if ((t = strstr(line, entry.domain)) != NULL &&
231 		    (line[l] == ' ' || line[l] == '\t'))
232 			continue;
233 		/* line has a trailing \n */
234 		fprintf(tmp, "%s", line);
235 	}
236 	fprintf(tmp, "%s %s %d\n", entry.domain, entry.hash, entry.verified);
237 
238 	free(line);
239 	e = ferror(tmp);
240 
241 	fclose(tmp);
242 	fclose(f);
243 
244 	if (e) {
245 		unlink(sfn);
246 		res = 0;
247 		goto end;
248 	}
249 
250 	res = rename(sfn, known_hosts_file) != -1;
251 
252 end:
253 	fs_send_ui(IMSG_UPDATE_CERT_OK, imsg->hdr.peerid, -1,
254 	    &res, sizeof(res));
255 }
256 
257 static void
258 handle_file_open(struct imsg *imsg, size_t datalen)
259 {
260 	char	*path, *e;
261 	int	 fd;
262 
263 	path = imsg->data;
264 	if (path[datalen-1] != '\0')
265 		die();
266 
267 	if ((fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, 0644)) == -1) {
268 		e = strerror(errno);
269 		fs_send_ui(IMSG_FILE_OPENED, imsg->hdr.peerid, -1,
270 		    e, strlen(e)+1);
271 	} else
272 		fs_send_ui(IMSG_FILE_OPENED, imsg->hdr.peerid, fd,
273 		    NULL, 0);
274 }
275 
276 static void
277 handle_session_start(struct imsg *imsg, size_t datalen)
278 {
279 	if (datalen != 0)
280 		die();
281 
282 	if ((session = fopen(session_file, "w")) == NULL)
283 		die();
284 }
285 
286 static void
287 handle_session_tab(struct imsg *imsg, size_t datalen)
288 {
289 	if (session == NULL)
290 		die();
291 
292 	if (datalen == 0)
293 		die();
294 
295 	/* skip the NUL-terminator */
296         fwrite(imsg->data, 1, datalen-1, session);
297 
298 	fprintf(session, "\n");
299 }
300 
301 static void
302 handle_session_end(struct imsg *imsg, size_t datalen)
303 {
304 	if (session == NULL)
305 		die();
306 	fclose(session);
307 	session = NULL;
308 }
309 
310 static void
311 handle_dispatch_imsg(int fd, short ev, void *d)
312 {
313 	struct imsgev	*iev = d;
314 	dispatch_imsg(iev, ev, handlers, sizeof(handlers));
315 }
316 
317 static int
318 fs_send_ui(int type, uint32_t peerid, int fd, const void *data,
319     uint16_t datalen)
320 {
321 	return imsg_compose_event(iev_ui, type, peerid, 0, fd,
322 	    data, datalen);
323 }
324 
325 int
326 fs_init(void)
327 {
328 	char	dir[PATH_MAX];
329 
330 	strlcpy(dir, getenv("HOME"), sizeof(dir));
331 	strlcat(dir, "/.telescope", sizeof(dir));
332 	mkdir(dir, 0700);
333 
334 	strlcpy(lockfile_path, getenv("HOME"), sizeof(lockfile_path));
335 	strlcat(lockfile_path, "/.telescope/lock", sizeof(lockfile_path));
336 
337 	strlcpy(bookmark_file, getenv("HOME"), sizeof(bookmark_file));
338 	strlcat(bookmark_file, "/.telescope/bookmarks.gmi", sizeof(bookmark_file));
339 
340 	strlcpy(known_hosts_file, getenv("HOME"), sizeof(known_hosts_file));
341 	strlcat(known_hosts_file, "/.telescope/known_hosts", sizeof(known_hosts_file));
342 
343 	strlcpy(known_hosts_tmp, getenv("HOME"), sizeof(known_hosts_tmp));
344 	strlcat(known_hosts_tmp, "/.telescope/known_hosts.tmp.XXXXXXXXXX",
345 	    sizeof(known_hosts_file));
346 
347 	strlcpy(session_file, getenv("HOME"), sizeof(session_file));
348 	strlcat(session_file, "/.telescope/session", sizeof(session_file));
349 
350 	return 1;
351 }
352 
353 int
354 fs_main(void)
355 {
356 	setproctitle("fs");
357 
358 	fs_init();
359 
360 	event_init();
361 
362 	/* Setup pipe and event handler to the main process */
363 	if ((iev_ui = malloc(sizeof(*iev_ui))) == NULL)
364 		die();
365 	imsg_init(&iev_ui->ibuf, 3);
366 	iev_ui->handler = handle_dispatch_imsg;
367 	iev_ui->events = EV_READ;
368 	event_set(&iev_ui->ev, iev_ui->ibuf.fd, iev_ui->events,
369 	    iev_ui->handler, iev_ui);
370 	event_add(&iev_ui->ev, NULL);
371 
372 	sandbox_fs_process();
373 
374 	event_dispatch();
375 	return 0;
376 }
377 
378 
379 
380 int
381 lock_session(void)
382 {
383 	struct flock	lock;
384 	int		fd;
385 
386 	if ((fd = open(lockfile_path, O_WRONLY|O_CREAT, 0600)) == -1)
387 		return -1;
388 
389 	lock.l_start = 0;
390 	lock.l_len = 0;
391 	lock.l_type = F_WRLCK;
392 	lock.l_whence = SEEK_SET;
393 
394 	if (fcntl(fd, F_SETLK, &lock) == -1) {
395 		close(fd);
396 		return -1;
397 	}
398 
399 	return fd;
400 }
401 
402 static int
403 parse_khost_line(char *line, char *tmp[3])
404 {
405 	char **ap;
406 
407 	for (ap = tmp; ap < &tmp[3] &&
408 	    (*ap = strsep(&line, " \t\n")) != NULL;) {
409 		if (**ap != '\0')
410 			ap++;
411 	}
412 
413 	return ap == &tmp[3] && *line == '\0';
414 }
415 
416 int
417 load_certs(struct ohash *h)
418 {
419 	char		*tmp[3], *line = NULL;
420 	const char	*errstr;
421 	size_t		 lineno = 0, linesize = 0;
422 	ssize_t		 linelen;
423 	FILE		*f;
424 	struct tofu_entry *e;
425 
426 	if ((f = fopen(known_hosts_file, "r")) == NULL)
427 		return 0;
428 
429 	while ((linelen = getline(&line, &linesize, f)) != -1) {
430 		if ((e = calloc(1, sizeof(*e))) == NULL)
431 			abort();
432 
433 		lineno++;
434 
435 		if (parse_khost_line(line, tmp)) {
436 			strlcpy(e->domain, tmp[0], sizeof(e->domain));
437 			strlcpy(e->hash, tmp[1], sizeof(e->hash));
438 
439 			e->verified = strtonum(tmp[2], 0, 1, &errstr);
440 			if (errstr != NULL)
441 				errx(1, "%s:%zu verification for %s is %s: %s",
442 				    known_hosts_file, lineno,
443 				    e->domain, errstr, tmp[2]);
444 			tofu_add(h, e);
445 		} else {
446 			warnx("%s:%zu invalid entry",
447 			    known_hosts_file, lineno);
448 			free(e);
449 		}
450 	}
451 
452 	free(line);
453 	return ferror(f);
454 }
455 
456 int
457 load_last_session(void (*cb)(const char*))
458 {
459 	char	*nl, *line = NULL;
460 	int	 e;
461 	size_t	 linesize = 0;
462 	ssize_t	 linelen;
463 	FILE	*session;
464 
465 	if ((session = fopen(session_file, "r")) == NULL) {
466 		/* first time? */
467 		cb("about:help");
468 		return 0;
469 	}
470 
471 	while ((linelen = getline(&line, &linesize, session)) != -1) {
472                 if ((nl = strchr(line, '\n')) != NULL)
473 			*nl = '\0';
474 		cb(line);
475 	}
476 
477 	free(line);
478 	e = ferror(session);
479 	fclose(session);
480 
481 	return !e;
482 }