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	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 		fs_send_ui(IMSG_BUF, peerid, -1, t, strlen(t));
89 		fs_send_ui(IMSG_EOF, peerid, -1, NULL, 0);
90 		return;
91 	}
92 
93 	for (;;) {
94 		r = fread(buf, 1, sizeof(buf), f);
95 		fs_send_ui(IMSG_BUF, peerid, -1, buf, r);
96 		if (r != sizeof(buf))
97 			break;
98 	}
99 
100 	fs_send_ui(IMSG_EOF, peerid, -1, NULL, 0);
101 
102 	fclose(f);
103 }
104 
105 static void
106 send_page(struct imsg *imsg, const char *page)
107 {
108 	fs_send_ui(IMSG_BUF, imsg->hdr.peerid, -1, page, strlen(page));
109 	fs_send_ui(IMSG_EOF, imsg->hdr.peerid, -1, NULL, 0);
110 }
111 
112 static void
113 handle_get(struct imsg *imsg, size_t datalen)
114 {
115 	char		*data;
116 	const char	*p;
117 
118 	data = imsg->data;
119 
120 	if (data[datalen-1] != '\0')
121 		die();
122 
123 	if (!strcmp(data, "about:about")) {
124 		send_page(imsg, about_about);
125 	} else if (!strcmp(data, "about:blank")) {
126 		send_page(imsg, about_blank);
127 	} else if (!strcmp(data, "about:bookmarks")) {
128 		serve_bookmarks(imsg->hdr.peerid);
129 	} else if (!strcmp(data, "about:help")) {
130 		send_page(imsg, about_help);
131 	} else if (!strcmp(data, "about:new")) {
132 		send_page(imsg, about_new);
133 	} else {
134 		p = "# not found!\n";
135 		fs_send_ui(IMSG_BUF, imsg->hdr.peerid, -1, p, strlen(p));
136 		fs_send_ui(IMSG_EOF, imsg->hdr.peerid, -1, NULL, 0);
137 	}
138 }
139 
140 static void
141 handle_quit(struct imsg *imsg, size_t datalen)
142 {
143 	event_loopbreak();
144 }
145 
146 static void
147 handle_bookmark_page(struct imsg *imsg, size_t datalen)
148 {
149 	char	*data;
150 	int	 res;
151 	FILE	*f;
152 
153 	data = imsg->data;
154 	if (data[datalen-1] != '\0')
155 		die();
156 
157 	if ((f = fopen(bookmark_file, "a")) == NULL) {
158 		res = errno;
159 		goto end;
160 	}
161 	fprintf(f, "=> %s\n", data);
162 	fclose(f);
163 
164 	res = 0;
165 end:
166 	fs_send_ui(IMSG_BOOKMARK_OK, 0, -1, &res, sizeof(res));
167 }
168 
169 static void
170 handle_save_cert(struct imsg *imsg, size_t datalen)
171 {
172 	struct tofu_entry	 e;
173 	FILE			*f;
174 	int			 res;
175 
176 	/* TODO: traverse the file to avoid duplications? */
177 
178 	if (datalen != sizeof(e))
179 		die();
180 	memcpy(&e, imsg->data, datalen);
181 
182 	if ((f = fopen(known_hosts_file, "a")) == NULL) {
183 		res = errno;
184 		goto end;
185 	}
186 	fprintf(f, "%s %s %d\n", e.domain, e.hash, e.verified);
187 	fclose(f);
188 
189 	res = 0;
190 end:
191 	fs_send_ui(IMSG_SAVE_CERT_OK, imsg->hdr.peerid, -1,
192 	    &res, sizeof(res));
193 }
194 
195 static void
196 handle_update_cert(struct imsg *imsg, size_t datalen)
197 {
198 	FILE	*tmp, *f;
199 	struct	 tofu_entry entry;
200 	char	 sfn[PATH_MAX], *line = NULL, *t;
201 	size_t	 l, linesize = 0;
202 	ssize_t	 linelen;
203 	int	 fd, e, res = 0;
204 
205 	if (datalen != sizeof(entry))
206 		die();
207 	memcpy(&entry, imsg->data, datalen);
208 
209 	strlcpy(sfn, known_hosts_tmp, sizeof(sfn));
210 	if ((fd = mkstemp(sfn)) == -1 ||
211 	    (tmp = fdopen(fd, "w")) == NULL) {
212 		if (fd != -1) {
213 			unlink(sfn);
214 			close(fd);
215 		}
216 		res = 0;
217 		goto end;
218 	}
219 
220 	if ((f = fopen(known_hosts_file, "r")) == NULL) {
221 		unlink(sfn);
222 		fclose(tmp);
223                 res = 0;
224 		goto end;
225 	}
226 
227 	l = strlen(entry.domain);
228 	while ((linelen = getline(&line, &linesize, f)) != -1) {
229 		if ((t = strstr(line, entry.domain)) != NULL &&
230 		    (line[l] == ' ' || line[l] == '\t'))
231 			continue;
232 		/* line has a trailing \n */
233 		fprintf(tmp, "%s", line);
234 	}
235 	fprintf(tmp, "%s %s %d\n", entry.domain, entry.hash, entry.verified);
236 
237 	free(line);
238 	e = ferror(tmp);
239 
240 	fclose(tmp);
241 	fclose(f);
242 
243 	if (e) {
244 		unlink(sfn);
245 		res = 0;
246 		goto end;
247 	}
248 
249 	res = rename(sfn, known_hosts_file) != -1;
250 
251 end:
252 	fs_send_ui(IMSG_UPDATE_CERT_OK, imsg->hdr.peerid, -1,
253 	    &res, sizeof(res));
254 }
255 
256 static void
257 handle_file_open(struct imsg *imsg, size_t datalen)
258 {
259 	char	*path, *e;
260 	int	 fd;
261 
262 	path = imsg->data;
263 	if (path[datalen-1] != '\0')
264 		die();
265 
266 	if ((fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, 0644)) == -1) {
267 		e = strerror(errno);
268 		fs_send_ui(IMSG_FILE_OPENED, imsg->hdr.peerid, -1,
269 		    e, strlen(e)+1);
270 	} else
271 		fs_send_ui(IMSG_FILE_OPENED, imsg->hdr.peerid, fd,
272 		    NULL, 0);
273 }
274 
275 static void
276 handle_session_start(struct imsg *imsg, size_t datalen)
277 {
278 	if (datalen != 0)
279 		die();
280 
281 	if ((session = fopen(session_file, "w")) == NULL)
282 		die();
283 }
284 
285 static void
286 handle_session_tab(struct imsg *imsg, size_t datalen)
287 {
288 	if (session == NULL)
289 		die();
290 
291 	if (datalen == 0)
292 		die();
293 
294 	/* skip the NUL-terminator */
295         fwrite(imsg->data, 1, datalen-1, session);
296 
297 	fprintf(session, "\n");
298 }
299 
300 static void
301 handle_session_end(struct imsg *imsg, size_t datalen)
302 {
303 	if (session == NULL)
304 		die();
305 	fclose(session);
306 	session = NULL;
307 }
308 
309 static void
310 handle_dispatch_imsg(int fd, short ev, void *d)
311 {
312 	struct imsgev	*iev = d;
313 	dispatch_imsg(iev, ev, handlers, sizeof(handlers));
314 }
315 
316 static int
317 fs_send_ui(int type, uint32_t peerid, int fd, const void *data,
318     uint16_t datalen)
319 {
320 	return imsg_compose_event(iev_ui, type, peerid, 0, fd,
321 	    data, datalen);
322 }
323 
324 int
325 fs_init(void)
326 {
327 	char	dir[PATH_MAX];
328 
329 	strlcpy(dir, getenv("HOME"), sizeof(dir));
330 	strlcat(dir, "/.telescope", sizeof(dir));
331 	mkdir(dir, 0700);
332 
333 	strlcpy(bookmark_file, getenv("HOME"), sizeof(bookmark_file));
334 	strlcat(bookmark_file, "/.telescope/bookmarks.gmi", sizeof(bookmark_file));
335 
336 	strlcpy(known_hosts_file, getenv("HOME"), sizeof(known_hosts_file));
337 	strlcat(known_hosts_file, "/.telescope/known_hosts", sizeof(known_hosts_file));
338 
339 	strlcpy(known_hosts_tmp, getenv("HOME"), sizeof(known_hosts_tmp));
340 	strlcat(known_hosts_tmp, "/.telescope/known_hosts.tmp.XXXXXXXXXX",
341 	    sizeof(known_hosts_file));
342 
343 	strlcpy(session_file, getenv("HOME"), sizeof(session_file));
344 	strlcat(session_file, "/.telescope/session", sizeof(session_file));
345 
346 	return 1;
347 }
348 
349 int
350 fs_main(void)
351 {
352 	setproctitle("fs");
353 
354 	fs_init();
355 
356 	event_init();
357 
358 	/* Setup pipe and event handler to the main process */
359 	if ((iev_ui = malloc(sizeof(*iev_ui))) == NULL)
360 		die();
361 	imsg_init(&iev_ui->ibuf, 3);
362 	iev_ui->handler = handle_dispatch_imsg;
363 	iev_ui->events = EV_READ;
364 	event_set(&iev_ui->ev, iev_ui->ibuf.fd, iev_ui->events,
365 	    iev_ui->handler, iev_ui);
366 	event_add(&iev_ui->ev, NULL);
367 
368 	sandbox_fs_process();
369 
370 	event_dispatch();
371 	return 0;
372 }
373 
374 
375 
376 static int
377 parse_khost_line(char *line, char *tmp[3])
378 {
379 	char **ap;
380 
381 	for (ap = tmp; ap < &tmp[3] &&
382 	    (*ap = strsep(&line, " \t\n")) != NULL;) {
383 		if (**ap != '\0')
384 			ap++;
385 	}
386 
387 	return ap == &tmp[3] && *line == '\0';
388 }
389 
390 int
391 load_certs(struct ohash *h)
392 {
393 	char		*tmp[3], *line = NULL;
394 	const char	*errstr;
395 	size_t		 lineno = 0, linesize = 0;
396 	ssize_t		 linelen;
397 	FILE		*f;
398 	struct tofu_entry *e;
399 
400 	if ((f = fopen(known_hosts_file, "r")) == NULL)
401 		return 0;
402 
403 	while ((linelen = getline(&line, &linesize, f)) != -1) {
404 		if ((e = calloc(1, sizeof(*e))) == NULL)
405 			abort();
406 
407 		lineno++;
408 
409 		if (parse_khost_line(line, tmp)) {
410 			strlcpy(e->domain, tmp[0], sizeof(e->domain));
411 			strlcpy(e->hash, tmp[1], sizeof(e->hash));
412 
413 			e->verified = strtonum(tmp[2], 0, 1, &errstr);
414 			if (errstr != NULL)
415 				errx(1, "%s:%zu verification for %s is %s: %s",
416 				    known_hosts_file, lineno,
417 				    e->domain, errstr, tmp[2]);
418 			tofu_add(h, e);
419 		} else {
420 			warnx("%s:%zu invalid entry",
421 			    known_hosts_file, lineno);
422 			free(e);
423 		}
424 	}
425 
426 	free(line);
427 	return ferror(f);
428 }
429 
430 int
431 load_last_session(void (*cb)(const char*))
432 {
433 	char	*nl, *line = NULL;
434 	int	 e;
435 	size_t	 linesize = 0;
436 	ssize_t	 linelen;
437 	FILE	*session;
438 
439 	if ((session = fopen(session_file, "r")) == NULL) {
440 		/* first time? */
441 		cb("about:help");
442 		return 0;
443 	}
444 
445 	while ((linelen = getline(&line, &linesize, session)) != -1) {
446                 if ((nl = strchr(line, '\n')) != NULL)
447 			*nl = '\0';
448 		cb(line);
449 	}
450 
451 	free(line);
452 	e = ferror(session);
453 	fclose(session);
454 
455 	return !e;
456 }