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