about summary refs log tree commit diff
path: root/imbox.c
blob: 9f469831da8b8078f4bacf5012ed9d492b90bb6f (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
/* Copyright (C) 2019  C. McEnroe <june@causal.agency>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#include <ctype.h>
#include <err.h>
#include <readpassphrase.h>
#include <regex.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <tls.h>
#include <unistd.h>

#define ARRAY_LEN(a) (sizeof(a) / sizeof((a)[0]))

static void compile(regex_t *regex, const char *pattern) {
	if (regex->re_nsub) return;
	int error = regcomp(regex, pattern, REG_EXTENDED | REG_NEWLINE);
	if (!error) return;
	char buf[256];
	regerror(error, regex, buf, sizeof(buf));
	errx(EX_SOFTWARE, "regcomp: %s: %s", buf, pattern);
}

static void mboxrd(const char *headers, const char *body) {
	static regex_t fromRegex;
	compile(&fromRegex, "^From: .*<([^>]+)>");

	regmatch_t from[2];
	int error = regexec(&fromRegex, headers, 2, from, 0);
	if (error) errx(EX_DATAERR, "missing From header");
	printf(
		"From %.*s ",
		(int)(from[1].rm_eo - from[1].rm_so), &headers[from[1].rm_so]
	);

	static regex_t dateRegex;
	compile(&dateRegex, "^Date: (...), (..) (...) (....) (.{8})");

	regmatch_t date[6];
	error = regexec(&dateRegex, headers, 6, date, 0);
	if (error) errx(EX_DATAERR, "missing Date header");
	printf(
		"%.*s %.*s %.*s %.*s %.*s\r\n",
		(int)(date[1].rm_eo - date[1].rm_so), &headers[date[1].rm_so],
		(int)(date[3].rm_eo - date[3].rm_so), &headers[date[3].rm_so],
		(int)(date[2].rm_eo - date[2].rm_so), &headers[date[2].rm_so],
		(int)(date[5].rm_eo - date[5].rm_so), &headers[date[5].rm_so],
		(int)(date[4].rm_eo - date[4].rm_so), &headers[date[4].rm_so]
	);

	printf("%s", headers);
	// FIXME: There seems to sometimes be some garbage data at the end of the
	// headers?

	static regex_t quoteRegex;
	compile(&quoteRegex, "^>*From ");
	regmatch_t match = {0};
	for (const char *ptr = body;; ptr += match.rm_eo) {
		regmatch_t match;
		error = regexec(
			&quoteRegex, body, 1, &match, (ptr > body ? REG_NOTBOL : 0)
		);
		if (error) {
			printf("%s", ptr);
			break;
		}
		printf(
			"%.*s>%.*s",
			(int)match.rm_so, ptr,
			(int)(match.rm_eo - match.rm_so), &ptr[match.rm_so]
		);
	}

	// FIXME: mbox technically shouldn't use \r\n but everything else does...
	printf("\r\n");
}

static bool verbose;

int tlsRead(void *_tls, char *ptr, int len) {
	struct tls *tls = _tls;
	ssize_t ret;
	do {
		ret = tls_read(tls, ptr, len);
	} while (ret == TLS_WANT_POLLIN || ret == TLS_WANT_POLLOUT);
	if (ret < 0) errx(EX_IOERR, "tls_read: %s", tls_error(tls));
	if (verbose) fprintf(stderr, "%.*s", (int)ret, ptr);
	return ret;
}

int tlsWrite(void *_tls, const char *ptr, int len) {
	struct tls *tls = _tls;
	ssize_t ret;
	do {
		ret = tls_write(tls, ptr, len);
	} while (ret == TLS_WANT_POLLIN || ret == TLS_WANT_POLLOUT);
	if (ret < 0) errx(EX_IOERR, "tls_write: %s", tls_error(tls));
	if (verbose) fprintf(stderr, "%.*s", (int)ret, ptr);
	return ret;
}

int tlsClose(void *_tls) {
	struct tls *tls = _tls;
	int error = tls_close(tls);
	if (error) errx(EX_IOERR, "tls_close: %s", tls_error(tls));
	return error;
}

#define ENUM_ATOM \
	X(Unknown, "") \
	X(Untagged, "*") \
	X(Ok, "OK") \
	X(No, "NO") \
	X(Bad, "BAD") \
	X(Bye, "BYE") \
	X(Login, "LOGIN") \
	X(Select, "SELECT") \
	X(Search, "SEARCH") \
	X(Fetch, "FETCH")

enum Atom {
#define X(id, _) id,
	ENUM_ATOM
#undef X
};

static const char *Atoms[] = {
#define X(id, str) [id] = str,
	ENUM_ATOM
#undef X
};

static enum Atom atom(const char *str) {
	if (!str) return Unknown;
	for (size_t i = 0; i < ARRAY_LEN(Atoms); ++i) {
		if (!strcmp(str, Atoms[i])) return i;
	}
	return Unknown;
}

static char *readLiteral(FILE *imap, const char *line) {
	char *prefix = strrchr(line, '{');
	if (!prefix) errx(EX_PROTOCOL, "no literal prefix");

	size_t size = strtoul(prefix + 1, NULL, 10);
	if (!size) errx(EX_PROTOCOL, "invalid literal size");

	char *literal = malloc(size);
	if (!literal) err(EX_OSERR, "malloc");

	size_t count = fread(literal, size, 1, imap);
	if (!count) errx(EX_PROTOCOL, "could not read literal");

	return literal;
}

int main(int argc, char *argv[]) {
	const char *host = "imap.fastmail.com";
	const char *port = "993";
	const char *mailbox = "INBOX";
	const char *search = "SUBJECT \"[PATCH\"";
	int rppFlags = 0;

	int opt;
	while (0 < (opt = getopt(argc, argv, "h:m:p:s:vw"))) {
		switch (opt) {
			break; case 'h': host = optarg;
			break; case 'm': mailbox = optarg;
			break; case 'p': port = optarg;
			break; case 's': search = optarg;
			break; case 'v': verbose = true;
			break; case 'w': rppFlags |= RPP_STDIN;
			break; default:  return EX_USAGE;
		}
	}

	const char *user = argv[optind];
	if (!user) errx(EX_USAGE, "username required");

	char buf[1024];
	char *pass = readpassphrase(
		(rppFlags & RPP_STDIN ? "" : "Password: "),
		buf, sizeof(buf), rppFlags
	);
	if (!pass) err(EX_UNAVAILABLE, "readpassphrase");

	struct tls *client = tls_client();
	if (!client) errx(EX_SOFTWARE, "tls_client");

	struct tls_config *config = tls_config_new();
	if (!config) errx(EX_SOFTWARE, "tls_config_new");

	int error = tls_configure(client, config);
	if (error) errx(EX_SOFTWARE, "tls_configure: %s", tls_error(client));
	tls_config_free(config);

	error = tls_connect(client, host, port);
	if (error) errx(EX_NOHOST, "tls_connect: %s", tls_error(client));

	FILE *imap = funopen(client, tlsRead, tlsWrite, NULL, tlsClose);
	if (!imap) err(EX_SOFTWARE, "funopen");

	bool login = false;
	char *uids = NULL;

	char *line = NULL;
	size_t cap = 0;
	while (0 < getline(&line, &cap, imap)) {
		if (strchr(line, '\r')) *strchr(line, '\r') = '\0';

		char *rest = line;
		enum Atom tag = atom(strsep(&rest, " "));
		if (rest && isdigit(rest[0])) strsep(&rest, " ");
		enum Atom resp = atom(strsep(&rest, " "));

		if (resp == No || resp == Bad) {
			errx(
				EX_CONFIG, "%s: %s %s",
				Atoms[tag], Atoms[resp], (rest ? rest : "")
			);
		} else if (resp == Bye) {
			errx(EX_UNAVAILABLE, "unexpected BYE: %s", (rest ? rest : ""));
		}

		switch (tag) {
			break; case Untagged: {
				if (login) break;
				fprintf(imap, "%s LOGIN %s %s\r\n", Atoms[Login], user, pass);
				login = true;
			}
			break; case Login: {
				fprintf(imap, "%s SELECT %s\r\n", Atoms[Select], mailbox);
			}
			break; case Select: {
				fprintf(
					imap, "%s UID SEARCH CHARSET UTF-8 %s\r\n",
					Atoms[Search], search
				);
			}
			break; case Search: {
				if (!uids) errx(EX_PROTOCOL, "no search response");
				for (char *ch = uids; *ch; ++ch) {
					if (*ch == ' ') *ch = ',';
				}
				// FIXME: Grab Content-Encoding as well?
				fprintf(
					imap,
					"%s UID FETCH %s ("
					"BODY[HEADER.FIELDS (Date From Subject Message-Id)] "
					"BODY[TEXT]"
					")\r\n",
					Atoms[Fetch], uids
				);
			}
			break; case Fetch: {
				fprintf(imap, "ayy LOGOUT\r\n");
				fclose(imap);
				return EX_OK;
			}
			break; default:;
		}

		switch (resp) {
			break; case Search: {
				if (!rest) errx(EX_TEMPFAIL, "no messages match");
				uids = strdup(rest);
				if (!uids) err(EX_OSERR, "strdup");
			}
			break; case Fetch: {
				char *headers = readLiteral(imap, rest);

				ssize_t len = getline(&line, &cap, imap);
				if (len <= 0) errx(EX_PROTOCOL, "unexpected eof");

				char *body = readLiteral(imap, line);

				len = getline(&line, &cap, imap);
				if (len <= 0) errx(EX_PROTOCOL, "unexpected eof");
				if (strcmp(line, ")\r\n")) {
					errx(EX_PROTOCOL, "trailing fetch data");
				}

				mboxrd(headers, body);
				free(headers);
				free(body);
			}
			break; default:;
		}
	}
}