1/* vi: set sw=4 ts=4: */
2/*
3 * makemime: create MIME-encoded message
4 * reformime: parse MIME-encoded message
5 *
6 * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
7 *
8 * Licensed under GPLv2, see file LICENSE in this tarball for details.
9 */
10#include "libbb.h"
11#include "mail.h"
12
13/*
14  makemime -c type [-o file] [-e encoding] [-C charset] [-N name] \
15                   [-a "Header: Contents"] file
16           -m [ type ] [-o file] [-e encoding] [-a "Header: Contents"] file
17           -j [-o file] file1 file2
18           @file
19
20   file:  filename    - read or write from filename
21          -           - read or write from stdin or stdout
22          &n          - read or write from file descriptor n
23          \( opts \)  - read from child process, that generates [ opts ]
24
25Options:
26
27  -c type         - create a new MIME section from "file" with this
28                    Content-Type: (default is application/octet-stream).
29  -C charset      - MIME charset of a new text/plain section.
30  -N name         - MIME content name of the new mime section.
31  -m [ type ]     - create a multipart mime section from "file" of this
32                    Content-Type: (default is multipart/mixed).
33  -e encoding     - use the given encoding (7bit, 8bit, quoted-printable,
34                    or base64), instead of guessing.  Omit "-e" and use
35                    -c auto to set Content-Type: to text/plain or
36                    application/octet-stream based on picked encoding.
37  -j file1 file2  - join mime section file2 to multipart section file1.
38  -o file         - write the result to file, instead of stdout (not
39                    allowed in child processes).
40  -a header       - prepend an additional header to the output.
41
42  @file - read all of the above options from file, one option or
43          value on each line.
44  {which version of makemime is this? What do we support?}
45*/
46
47
48/* In busybox 1.15.0.svn, makemime generates output like this
49 * (empty lines are shown exactly!):
50{headers added with -a HDR}
51Mime-Version: 1.0
52Content-Type: multipart/mixed; boundary="24269534-2145583448-1655890676"
53
54--24269534-2145583448-1655890676
55Content-Type: {set by -c, e.g. text/plain}; charset={set by -C, e.g. us-ascii}
56Content-Disposition: inline; filename="A"
57Content-Transfer-Encoding: base64
58
59...file A contents...
60--24269534-2145583448-1655890676
61Content-Type: {set by -c, e.g. text/plain}; charset={set by -C, e.g. us-ascii}
62Content-Disposition: inline; filename="B"
63Content-Transfer-Encoding: base64
64
65...file B contents...
66--24269534-2145583448-1655890676--
67
68*/
69
70
71/* For reference: here is an example email to LKML which has
72 * 1st unnamed part (so it serves as an email body)
73 * and one attached file:
74...other headers...
75Content-Type: multipart/mixed; boundary="=-tOfTf3byOS0vZgxEWcX+"
76...other headers...
77Mime-Version: 1.0
78...other headers...
79
80
81--=-tOfTf3byOS0vZgxEWcX+
82Content-Type: text/plain
83Content-Transfer-Encoding: 7bit
84
85...email text...
86...email text...
87
88
89--=-tOfTf3byOS0vZgxEWcX+
90Content-Disposition: attachment; filename="xyz"
91Content-Type: text/plain; name="xyz"; charset="UTF-8"
92Content-Transfer-Encoding: 7bit
93
94...file contents...
95...file contents...
96
97--=-tOfTf3byOS0vZgxEWcX+--
98
99...random junk added by mailing list robots and such...
100*/
101
102int makemime_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
103int makemime_main(int argc UNUSED_PARAM, char **argv)
104{
105	llist_t *opt_headers = NULL, *l;
106	const char *opt_output;
107#define boundary opt_output
108
109	enum {
110		OPT_c = 1 << 0,         // Content-Type:
111		OPT_e = 1 << 1,         // Content-Transfer-Encoding. Ignored. Assumed base64
112		OPT_o = 1 << 2,         // output to
113		OPT_C = 1 << 3,         // charset
114		OPT_N = 1 << 4,         // COMPAT
115		OPT_a = 1 << 5,         // additional headers
116		OPT_m = 1 << 6,         // COMPAT
117		OPT_j = 1 << 7,         // COMPAT
118	};
119
120	INIT_G();
121
122	// parse options
123	opt_complementary = "a::";
124	opts = getopt32(argv,
125		"c:e:o:C:N:a:m:j:",
126		&G.content_type, NULL, &opt_output, &G.opt_charset, NULL, &opt_headers, NULL, NULL
127	);
128	//argc -= optind;
129	argv += optind;
130
131	// respect -o output
132	if (opts & OPT_o)
133		freopen(opt_output, "w", stdout);
134
135	// no files given on command line? -> use stdin
136	if (!*argv)
137		*--argv = (char *)"-";
138
139	// put additional headers
140	for (l = opt_headers; l; l = l->link)
141		puts(l->data);
142
143	// make a random string -- it will delimit message parts
144	srand(monotonic_us());
145	boundary = xasprintf("%u-%u-%u",
146			(unsigned)rand(), (unsigned)rand(), (unsigned)rand());
147
148	// put multipart header
149	printf(
150		"Mime-Version: 1.0\n"
151		"Content-Type: multipart/mixed; boundary=\"%s\"\n"
152		, boundary
153	);
154
155	// put attachments
156	while (*argv) {
157		printf(
158			"\n--%s\n"
159			"Content-Type: %s; charset=%s\n"
160			"Content-Disposition: inline; filename=\"%s\"\n"
161			"Content-Transfer-Encoding: base64\n"
162			, boundary
163			, G.content_type
164			, G.opt_charset
165			, bb_get_last_path_component_strip(*argv)
166		);
167		encode_base64(*argv++, (const char *)stdin, "");
168	}
169
170	// put multipart footer
171	printf("\n--%s--\n" "\n", boundary);
172
173	return EXIT_SUCCESS;
174#undef boundary
175}
176
177static const char *find_token(const char *const string_array[], const char *key, const char *defvalue)
178{
179	const char *r = NULL;
180	int i;
181	for (i = 0; string_array[i] != NULL; i++) {
182		if (strcasecmp(string_array[i], key) == 0) {
183			r = (char *)string_array[i+1];
184			break;
185		}
186	}
187	return (r) ? r : defvalue;
188}
189
190static const char *xfind_token(const char *const string_array[], const char *key)
191{
192	const char *r = find_token(string_array, key, NULL);
193	if (r)
194		return r;
195	bb_error_msg_and_die("header: %s", key);
196}
197
198enum {
199	OPT_x = 1 << 0,
200	OPT_X = 1 << 1,
201#if ENABLE_FEATURE_REFORMIME_COMPAT
202	OPT_d = 1 << 2,
203	OPT_e = 1 << 3,
204	OPT_i = 1 << 4,
205	OPT_s = 1 << 5,
206	OPT_r = 1 << 6,
207	OPT_c = 1 << 7,
208	OPT_m = 1 << 8,
209	OPT_h = 1 << 9,
210	OPT_o = 1 << 10,
211	OPT_O = 1 << 11,
212#endif
213};
214
215static int parse(const char *boundary, char **argv)
216{
217	char *line, *s, *p;
218	const char *type;
219	int boundary_len = strlen(boundary);
220	const char *delims = " ;\"\t\r\n";
221	const char *uniq;
222	int ntokens;
223	const char *tokens[32]; // 32 is enough
224
225	// prepare unique string pattern
226	uniq = xasprintf("%%llu.%u.%s", (unsigned)getpid(), safe_gethostname());
227
228//bb_info_msg("PARSE[%s]", terminator);
229
230	while ((line = xmalloc_fgets_str(stdin, "\r\n\r\n")) != NULL) {
231
232		// seek to start of MIME section
233		// N.B. to avoid false positives let us seek to the _last_ occurance
234		p = NULL;
235		s = line;
236		while ((s = strcasestr(s, "Content-Type:")) != NULL)
237			p = s++;
238		if (!p)
239			goto next;
240//bb_info_msg("L[%s]", p);
241
242		// split to tokens
243		// TODO: strip of comments which are of form: (comment-text)
244		ntokens = 0;
245		tokens[ntokens] = NULL;
246		for (s = strtok(p, delims); s; s = strtok(NULL, delims)) {
247			tokens[ntokens] = s;
248			if (ntokens < ARRAY_SIZE(tokens) - 1)
249				ntokens++;
250//bb_info_msg("L[%d][%s]", ntokens, s);
251		}
252		tokens[ntokens] = NULL;
253//bb_info_msg("N[%d]", ntokens);
254
255		// analyse tokens
256		type = find_token(tokens, "Content-Type:", "text/plain");
257//bb_info_msg("T[%s]", type);
258		if (0 == strncasecmp(type, "multipart/", 10)) {
259			if (0 == strcasecmp(type+10, "mixed")) {
260				parse(xfind_token(tokens, "boundary="), argv);
261			} else
262				bb_error_msg_and_die("no support of content type '%s'", type);
263		} else {
264			pid_t pid = pid;
265			int rc;
266			FILE *fp;
267			// fetch charset
268			const char *charset = find_token(tokens, "charset=", CONFIG_FEATURE_MIME_CHARSET);
269			// fetch encoding
270			const char *encoding = find_token(tokens, "Content-Transfer-Encoding:", "7bit");
271			// compose target filename
272			char *filename = (char *)find_token(tokens, "filename=", NULL);
273			if (!filename)
274				filename = xasprintf(uniq, monotonic_us());
275			else
276				filename = bb_get_last_path_component_strip(xstrdup(filename));
277
278			// start external helper, if any
279			if (opts & OPT_X) {
280				int fd[2];
281				xpipe(fd);
282				pid = vfork();
283				if (0 == pid) {
284					// child reads from fd[0]
285					close(fd[1]);
286					xmove_fd(fd[0], STDIN_FILENO);
287					xsetenv("CONTENT_TYPE", type);
288					xsetenv("CHARSET", charset);
289					xsetenv("ENCODING", encoding);
290					xsetenv("FILENAME", filename);
291					BB_EXECVP_or_die(argv);
292				}
293				// parent dumps to fd[1]
294				close(fd[0]);
295				fp = xfdopen_for_write(fd[1]);
296				signal(SIGPIPE, SIG_IGN); // ignore EPIPE
297			// or create a file for dump
298			} else {
299				char *fname = xasprintf("%s%s", *argv, filename);
300				fp = xfopen_for_write(fname);
301				free(fname);
302			}
303
304			// housekeeping
305			free(filename);
306
307			// dump to fp
308			if (0 == strcasecmp(encoding, "base64")) {
309				decode_base64(stdin, fp);
310			} else if (0 != strcasecmp(encoding, "7bit")
311				&& 0 != strcasecmp(encoding, "8bit")
312			) {
313				// quoted-printable, binary, user-defined are unsupported so far
314				bb_error_msg_and_die("no support of encoding '%s'", encoding);
315			} else {
316				// N.B. we have written redundant \n. so truncate the file
317				// The following weird 2-tacts reading technique is due to
318				// we have to not write extra \n at the end of the file
319				// In case of -x option we could truncate the resulting file as
320				// fseek(fp, -1, SEEK_END);
321				// if (ftruncate(fileno(fp), ftell(fp)))
322				//	bb_perror_msg("ftruncate");
323				// But in case of -X we have to be much more careful. There is
324				// no means to truncate what we already have sent to the helper.
325				p = xmalloc_fgets_str(stdin, "\r\n");
326				while (p) {
327					s = xmalloc_fgets_str(stdin, "\r\n");
328					if (s == NULL)
329						break;
330					if ('-' == s[0]
331					 && '-' == s[1]
332					 && 0 == strncmp(s+2, boundary, boundary_len)
333					) {
334						break;
335					}
336					fputs(p, fp);
337					p = s;
338				}
339
340/*
341				while ((s = xmalloc_fgetline_str(stdin, "\r\n")) != NULL) {
342					if ('-' == s[0] && '-' == s[1]
343						&& 0 == strncmp(s+2, boundary, boundary_len))
344						break;
345					fprintf(fp, "%s\n", s);
346				}
347				// N.B. we have written redundant \n. so truncate the file
348				fseek(fp, -1, SEEK_END);
349				if (ftruncate(fileno(fp), ftell(fp)))
350					bb_perror_msg("ftruncate");
351*/
352			}
353			fclose(fp);
354
355			// finalize helper
356			if (opts & OPT_X) {
357				signal(SIGPIPE, SIG_DFL);
358				// exit if helper exited >0
359				rc = (wait4pid(pid) & 0xff);
360				if (rc)
361					return rc+20;
362			}
363
364			// check multipart finalized
365			if (s && '-' == s[2+boundary_len] && '-' == s[2+boundary_len+1]) {
366				free(line);
367				break;
368			}
369		}
370 next:
371		free(line);
372	}
373
374//bb_info_msg("ENDPARSE[%s]", boundary);
375
376	return EXIT_SUCCESS;
377}
378
379/*
380Usage: reformime [options]
381    -d - parse a delivery status notification.
382    -e - extract contents of MIME section.
383    -x - extract MIME section to a file.
384    -X - pipe MIME section to a program.
385    -i - show MIME info.
386    -s n.n.n.n - specify MIME section.
387    -r - rewrite message, filling in missing MIME headers.
388    -r7 - also convert 8bit/raw encoding to quoted-printable, if possible.
389    -r8 - also convert quoted-printable encoding to 8bit, if possible.
390    -c charset - default charset for rewriting, -o, and -O.
391    -m [file] [file]... - create a MIME message digest.
392    -h "header" - decode RFC 2047-encoded header.
393    -o "header" - encode unstructured header using RFC 2047.
394    -O "header" - encode address list header using RFC 2047.
395*/
396
397int reformime_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
398int reformime_main(int argc UNUSED_PARAM, char **argv)
399{
400	const char *opt_prefix = "";
401
402	INIT_G();
403
404	// parse options
405	// N.B. only -x and -X are supported so far
406	opt_complementary = "x--X:X--x" IF_FEATURE_REFORMIME_COMPAT(":m::");
407	opts = getopt32(argv,
408		"x:X" IF_FEATURE_REFORMIME_COMPAT("deis:r:c:m:h:o:O:"),
409		&opt_prefix
410		IF_FEATURE_REFORMIME_COMPAT(, NULL, NULL, &G.opt_charset, NULL, NULL, NULL, NULL)
411	);
412	//argc -= optind;
413	argv += optind;
414
415	return parse("", (opts & OPT_X) ? argv : (char **)&opt_prefix);
416}
417