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