1/*
2 * Another stupid program, this one parsing the headers of an
3 * email to figure out authorship and subject
4 */
5#define _GNU_SOURCE
6#include <stdio.h>
7#include <stdlib.h>
8#include <string.h>
9#include <ctype.h>
10#include <iconv.h>
11static FILE *cmitmsg, *patchfile;
13static int keep_subject = 0;
15static int metainfo_utf8 = 0;
16static char line[1000];
17static char date[1000];
18static char name[1000];
19static char email[1000];
20static char subject[1000];
21static enum {
23 TE_DONTCARE, TE_QP, TE_BASE64,
24} transfer_encoding;
25static char charset[256];
26static char multipart_boundary[1000];
28static int multipart_boundary_len;
29static int patch_lines = 0;
30static char *sanity_check(char *name, char *email)
32{
33 int len = strlen(name);
34 if (len < 3 || len > 60)
35 return email;
36 if (strchr(name, '@') || strchr(name, '<') || strchr(name, '>'))
37 return email;
38 return name;
39}
40static int handle_from(char *line)
42{
43 char *at = strchr(line, '@');
44 char *dst;
45 if (!at)
47 return 0;
48 /*
50 * If we already have one email, don't take any confusing lines
51 */
52 if (*email && strchr(at+1, '@'))
53 return 0;
54 /* Pick up the string around '@', possibly delimited with <>
56 * pair; that is the email part. White them out while copying.
57 */
58 while (at > line) {
59 char c = at[-1];
60 if (isspace(c))
61 break;
62 if (c == '<') {
63 at[-1] = ' ';
64 break;
65 }
66 at--;
67 }
68 dst = email;
69 for (;;) {
70 unsigned char c = *at;
71 if (!c || c == '>' || isspace(c)) {
72 if (c == '>')
73 *at = ' ';
74 break;
75 }
76 *at++ = ' ';
77 *dst++ = c;
78 }
79 *dst++ = 0;
80 /* The remainder is name. It could be "John Doe <john.doe@xz>"
82 * or "john.doe@xz (John Doe)", but we have whited out the
83 * email part, so trim from both ends, possibly removing
84 * the () pair at the end.
85 */
86 at = line + strlen(line);
87 while (at > line) {
88 unsigned char c = *--at;
89 if (!isspace(c)) {
90 at[(c == ')') ? 0 : 1] = 0;
91 break;
92 }
93 }
94 at = line;
96 for (;;) {
97 unsigned char c = *at;
98 if (!c || !isspace(c)) {
99 if (c == '(')
100 at++;
101 break;
102 }
103 at++;
104 }
105 at = sanity_check(at, email);
106 strcpy(name, at);
107 return 1;
108}
109static int handle_date(char *line)
111{
112 strcpy(date, line);
113 return 0;
114}
115static int handle_subject(char *line)
117{
118 strcpy(subject, line);
119 return 0;
120}
121/* NOTE NOTE NOTE. We do not claim we do full MIME. We just attempt
123 * to have enough heuristics to grok MIME encoded patches often found
124 * on our mailing lists. For example, we do not even treat header lines
125 * case insensitively.
126 */
127static int slurp_attr(const char *line, const char *name, char *attr)
129{
130 char *ends, *ap = strcasestr(line, name);
131 size_t sz;
132 if (!ap) {
134 *attr = 0;
135 return 0;
136 }
137 ap += strlen(name);
138 if (*ap == '"') {
139 ap++;
140 ends = "\"";
141 }
142 else
143 ends = "; \t";
144 sz = strcspn(ap, ends);
145 memcpy(attr, ap, sz);
146 attr[sz] = 0;
147 return 1;
148}
149static int handle_subcontent_type(char *line)
151{
152 /* We do not want to mess with boundary. Note that we do not
153 * handle nested multipart.
154 */
155 if (strcasestr(line, "boundary=")) {
156 fprintf(stderr, "Not handling nested multipart message.\n");
157 exit(1);
158 }
159 slurp_attr(line, "charset=", charset);
160 if (*charset) {
161 int i, c;
162 for (i = 0; (c = charset[i]) != 0; i++)
163 charset[i] = tolower(c);
164 }
165 return 0;
166}
167static int handle_content_type(char *line)
169{
170 *multipart_boundary = 0;
171 if (slurp_attr(line, "boundary=", multipart_boundary + 2)) {
172 memcpy(multipart_boundary, "--", 2);
173 multipart_boundary_len = strlen(multipart_boundary);
174 }
175 slurp_attr(line, "charset=", charset);
176 return 0;
177}
178static int handle_content_transfer_encoding(char *line)
180{
181 if (strcasestr(line, "base64"))
182 transfer_encoding = TE_BASE64;
183 else if (strcasestr(line, "quoted-printable"))
184 transfer_encoding = TE_QP;
185 else
186 transfer_encoding = TE_DONTCARE;
187 return 0;
188}
189static int is_multipart_boundary(const char *line)
191{
192 return (!memcmp(line, multipart_boundary, multipart_boundary_len));
193}
194static int eatspace(char *line)
196{
197 int len = strlen(line);
198 while (len > 0 && isspace(line[len-1]))
199 line[--len] = 0;
200 return len;
201}
202#define SEEN_FROM 01
204#define SEEN_DATE 02
205#define SEEN_SUBJECT 04
206/* First lines of body can have From:, Date:, and Subject: */
208static int handle_inbody_header(int *seen, char *line)
209{
210 if (!memcmp("From:", line, 5) && isspace(line[5])) {
211 if (!(*seen & SEEN_FROM) && handle_from(line+6)) {
212 *seen |= SEEN_FROM;
213 return 1;
214 }
215 }
216 if (!memcmp("Date:", line, 5) && isspace(line[5])) {
217 if (!(*seen & SEEN_DATE)) {
218 handle_date(line+6);
219 *seen |= SEEN_DATE;
220 return 1;
221 }
222 }
223 if (!memcmp("Subject:", line, 8) && isspace(line[8])) {
224 if (!(*seen & SEEN_SUBJECT)) {
225 handle_subject(line+9);
226 *seen |= SEEN_SUBJECT;
227 return 1;
228 }
229 }
230 if (!memcmp("[PATCH]", line, 7) && isspace(line[7])) {
231 if (!(*seen & SEEN_SUBJECT)) {
232 handle_subject(line);
233 *seen |= SEEN_SUBJECT;
234 return 1;
235 }
236 }
237 return 0;
238}
239static char *cleanup_subject(char *subject)
241{
242 if (keep_subject)
243 return subject;
244 for (;;) {
245 char *p;
246 int len, remove;
247 switch (*subject) {
248 case 'r': case 'R':
249 if (!memcmp("e:", subject+1, 2)) {
250 subject +=3;
251 continue;
252 }
253 break;
254 case ' ': case '\t': case ':':
255 subject++;
256 continue;
257 case '[':
259 p = strchr(subject, ']');
260 if (!p) {
261 subject++;
262 continue;
263 }
264 len = strlen(p);
265 remove = p - subject;
266 if (remove <= len *2) {
267 subject = p+1;
268 continue;
269 }
270 break;
271 }
272 return subject;
273 }
274}
275static void cleanup_space(char *buf)
277{
278 unsigned char c;
279 while ((c = *buf) != 0) {
280 buf++;
281 if (isspace(c)) {
282 buf[-1] = ' ';
283 c = *buf;
284 while (isspace(c)) {
285 int len = strlen(buf);
286 memmove(buf, buf+1, len);
287 c = *buf;
288 }
289 }
290 }
291}
292typedef int (*header_fn_t)(char *);
294struct header_def {
295 const char *name;
296 header_fn_t func;
297 int namelen;
298};
299static void check_header(char *line, int len, struct header_def *header)
301{
302 int i;
303 if (header[0].namelen <= 0) {
305 for (i = 0; header[i].name; i++)
306 header[i].namelen = strlen(header[i].name);
307 }
308 for (i = 0; header[i].name; i++) {
309 int len = header[i].namelen;
310 if (!strncasecmp(line, header[i].name, len) &&
311 line[len] == ':' && isspace(line[len + 1])) {
312 header[i].func(line + len + 2);
313 break;
314 }
315 }
316}
317static void check_subheader_line(char *line, int len)
319{
320 static struct header_def header[] = {
321 { "Content-Type", handle_subcontent_type },
322 { "Content-Transfer-Encoding",
323 handle_content_transfer_encoding },
324 { NULL },
325 };
326 check_header(line, len, header);
327}
328static void check_header_line(char *line, int len)
329{
330 static struct header_def header[] = {
331 { "From", handle_from },
332 { "Date", handle_date },
333 { "Subject", handle_subject },
334 { "Content-Type", handle_content_type },
335 { "Content-Transfer-Encoding",
336 handle_content_transfer_encoding },
337 { NULL },
338 };
339 check_header(line, len, header);
340}
341static int read_one_header_line(char *line, int sz, FILE *in)
343{
344 int ofs = 0;
345 while (ofs < sz) {
346 int peek, len;
347 if (fgets(line + ofs, sz - ofs, in) == NULL)
348 return ofs;
349 len = eatspace(line + ofs);
350 if (len == 0)
351 return ofs;
352 peek = fgetc(in); ungetc(peek, in);
353 if (peek == ' ' || peek == '\t') {
354 /* Yuck, 2822 header "folding" */
355 ofs += len;
356 continue;
357 }
358 return ofs + len;
359 }
360 return ofs;
361}
362static unsigned hexval(int c)
364{
365 if (c >= '0' && c <= '9')
366 return c - '0';
367 if (c >= 'a' && c <= 'f')
368 return c - 'a' + 10;
369 if (c >= 'A' && c <= 'F')
370 return c - 'A' + 10;
371 return ~0;
372}
373static int decode_q_segment(char *in, char *ot, char *ep)
375{
376 int c;
377 while ((c = *in++) != 0 && (in <= ep)) {
378 if (c == '=') {
379 int d = *in++;
380 if (d == '\n' || !d)
381 break; /* drop trailing newline */
382 *ot++ = ((hexval(d) << 4) | hexval(*in++));
383 }
384 else
385 *ot++ = c;
386 }
387 *ot = 0;
388 return 0;
389}
390static int decode_b_segment(char *in, char *ot, char *ep)
392{
393 /* Decode in..ep, possibly in-place to ot */
394 int c, pos = 0, acc = 0;
395 while ((c = *in++) != 0 && (in <= ep)) {
397 if (c == '+')
398 c = 62;
399 else if (c == '/')
400 c = 63;
401 else if ('A' <= c && c <= 'Z')
402 c -= 'A';
403 else if ('a' <= c && c <= 'z')
404 c -= 'a' - 26;
405 else if ('0' <= c && c <= '9')
406 c -= '0' - 52;
407 else if (c == '=') {
408 /* padding is almost like (c == 0), except we do
409 * not output NUL resulting only from it;
410 * for now we just trust the data.
411 */
412 c = 0;
413 }
414 else
415 continue; /* garbage */
416 switch (pos++) {
417 case 0:
418 acc = (c << 2);
419 break;
420 case 1:
421 *ot++ = (acc | (c >> 4));
422 acc = (c & 15) << 4;
423 break;
424 case 2:
425 *ot++ = (acc | (c >> 2));
426 acc = (c & 3) << 6;
427 break;
428 case 3:
429 *ot++ = (acc | c);
430 acc = pos = 0;
431 break;
432 }
433 }
434 *ot = 0;
435 return 0;
436}
437static void convert_to_utf8(char *line, char *charset)
439{
440 if (*charset) {
441 char *in, *out;
442 size_t insize, outsize, nrc;
443 char outbuf[4096]; /* cheat */
444 iconv_t conv = iconv_open("utf-8", charset);
445 if (conv == (iconv_t) -1) {
447 fprintf(stderr, "cannot convert from %s to utf-8\n",
448 charset);
449 *charset = 0;
450 return;
451 }
452 in = line;
453 insize = strlen(in);
454 out = outbuf;
455 outsize = sizeof(outbuf);
456 nrc = iconv(conv, &in, &insize, &out, &outsize);
457 iconv_close(conv);
458 if (nrc == (size_t) -1)
459 return;
460 *out = 0;
461 strcpy(line, outbuf);
462 }
463}
464static void decode_header_bq(char *it)
466{
467 char *in, *out, *ep, *cp, *sp;
468 char outbuf[1000];
469 in = it;
471 out = outbuf;
472 while ((ep = strstr(in, "=?")) != NULL) {
473 int sz, encoding;
474 char charset_q[256], piecebuf[256];
475 if (in != ep) {
476 sz = ep - in;
477 memcpy(out, in, sz);
478 out += sz;
479 in += sz;
480 }
481 /* E.g.
482 * ep : "=?iso-2022-jp?B?GyR...?= foo"
483 * ep : "=?ISO-8859-1?Q?Foo=FCbar?= baz"
484 */
485 ep += 2;
486 cp = strchr(ep, '?');
487 if (!cp)
488 return; /* no munging */
489 for (sp = ep; sp < cp; sp++)
490 charset_q[sp - ep] = tolower(*sp);
491 charset_q[cp - ep] = 0;
492 encoding = cp[1];
493 if (!encoding || cp[2] != '?')
494 return; /* no munging */
495 ep = strstr(cp + 3, "?=");
496 if (!ep)
497 return; /* no munging */
498 switch (tolower(encoding)) {
499 default:
500 return; /* no munging */
501 case 'b':
502 sz = decode_b_segment(cp + 3, piecebuf, ep);
503 break;
504 case 'q':
505 sz = decode_q_segment(cp + 3, piecebuf, ep);
506 break;
507 }
508 if (sz < 0)
509 return;
510 if (metainfo_utf8)
511 convert_to_utf8(piecebuf, charset_q);
512 strcpy(out, piecebuf);
513 out += strlen(out);
514 in = ep + 2;
515 }
516 strcpy(out, in);
517 strcpy(it, outbuf);
518}
519static void decode_transfer_encoding(char *line)
521{
522 char *ep;
523 switch (transfer_encoding) {
525 case TE_QP:
526 ep = line + strlen(line);
527 decode_q_segment(line, line, ep);
528 break;
529 case TE_BASE64:
530 ep = line + strlen(line);
531 decode_b_segment(line, line, ep);
532 break;
533 case TE_DONTCARE:
534 break;
535 }
536}
537static void handle_info(void)
539{
540 char *sub;
541 static int done_info = 0;
542 if (done_info)
544 return;
545 done_info = 1;
547 sub = cleanup_subject(subject);
548 cleanup_space(name);
549 cleanup_space(date);
550 cleanup_space(email);
551 cleanup_space(sub);
552 /* Unwrap inline B and Q encoding, and optionally
554 * normalize the meta information to utf8.
555 */
556 decode_header_bq(name);
557 decode_header_bq(date);
558 decode_header_bq(email);
559 decode_header_bq(sub);
560 printf("Author: %s\nEmail: %s\nSubject: %s\nDate: %s\n\n",
561 name, email, sub, date);
562}
563/* We are inside message body and have read line[] already.
565 * Spit out the commit log.
566 */
567static int handle_commit_msg(void)
568{
569 if (!cmitmsg)
570 return 0;
571 do {
572 if (!memcmp("diff -", line, 6) ||
573 !memcmp("---", line, 3) ||
574 !memcmp("Index: ", line, 7))
575 break;
576 if ((multipart_boundary[0] && is_multipart_boundary(line))) {
577 /* We come here when the first part had only
578 * the commit message without any patch. We
579 * pretend we have not seen this line yet, and
580 * go back to the loop.
581 */
582 return 1;
583 }
584 /* Unwrap transfer encoding and optionally
586 * normalize the log message to UTF-8.
587 */
588 decode_transfer_encoding(line);
589 if (metainfo_utf8)
590 convert_to_utf8(line, charset);
591 fputs(line, cmitmsg);
592 } while (fgets(line, sizeof(line), stdin) != NULL);
593 fclose(cmitmsg);
594 cmitmsg = NULL;
595 return 0;
596}
597/* We have done the commit message and have the first
599 * line of the patch in line[].
600 */
601static void handle_patch(void)
602{
603 do {
604 if (multipart_boundary[0] && is_multipart_boundary(line))
605 break;
606 /* Only unwrap transfer encoding but otherwise do not
607 * do anything. We do *NOT* want UTF-8 conversion
608 * here; we are dealing with the user payload.
609 */
610 decode_transfer_encoding(line);
611 fputs(line, patchfile);
612 patch_lines++;
613 } while (fgets(line, sizeof(line), stdin) != NULL);
614}
615/* multipart boundary and transfer encoding are set up for us, and we
617 * are at the end of the sub header. do equivalent of handle_body up
618 * to the next boundary without closing patchfile --- we will expect
619 * that the first part to contain commit message and a patch, and
620 * handle other parts as pure patches.
621 */
622static int handle_multipart_one_part(void)
623{
624 int seen = 0;
625 int n = 0;
626 int len;
627 while (fgets(line, sizeof(line), stdin) != NULL) {
629 again:
630 len = eatspace(line);
631 n++;
632 if (!len)
633 continue;
634 if (is_multipart_boundary(line))
635 break;
636 if (0 <= seen && handle_inbody_header(&seen, line))
637 continue;
638 seen = -1; /* no more inbody headers */
639 line[len] = '\n';
640 handle_info();
641 if (handle_commit_msg())
642 goto again;
643 handle_patch();
644 break;
645 }
646 if (n == 0)
647 return -1;
648 return 0;
649}
650static void handle_multipart_body(void)
652{
653 int part_num = 0;
654 /* Skip up to the first boundary */
656 while (fgets(line, sizeof(line), stdin) != NULL)
657 if (is_multipart_boundary(line)) {
658 part_num = 1;
659 break;
660 }
661 if (!part_num)
662 return;
663 /* We are on boundary line. Start slurping the subhead. */
664 while (1) {
665 int len = read_one_header_line(line, sizeof(line), stdin);
666 if (!len) {
667 if (handle_multipart_one_part() < 0)
668 return;
669 }
670 else
671 check_subheader_line(line, len);
672 }
673 fclose(patchfile);
674 if (!patch_lines) {
675 fprintf(stderr, "No patch found\n");
676 exit(1);
677 }
678}
679/* Non multipart message */
681static void handle_body(void)
682{
683 int seen = 0;
684 while (fgets(line, sizeof(line), stdin) != NULL) {
686 int len = eatspace(line);
687 if (!len)
688 continue;
689 if (0 <= seen && handle_inbody_header(&seen, line))
690 continue;
691 seen = -1; /* no more inbody headers */
692 line[len] = '\n';
693 handle_info();
694 handle_commit_msg();
695 handle_patch();
696 break;
697 }
698 fclose(patchfile);
699 if (!patch_lines) {
700 fprintf(stderr, "No patch found\n");
701 exit(1);
702 }
703}
704static const char mailinfo_usage[] =
706 "git-mailinfo [-k] [-u] msg patch <mail >info";
707static void usage(void) {
709 fprintf(stderr, "%s\n", mailinfo_usage);
710 exit(1);
711}
712int main(int argc, char **argv)
714{
715 while (1 < argc && argv[1][0] == '-') {
716 if (!strcmp(argv[1], "-k"))
717 keep_subject = 1;
718 else if (!strcmp(argv[1], "-u"))
719 metainfo_utf8 = 1;
720 else
721 usage();
722 argc--; argv++;
723 }
724 if (argc != 3)
726 usage();
727 cmitmsg = fopen(argv[1], "w");
728 if (!cmitmsg) {
729 perror(argv[1]);
730 exit(1);
731 }
732 patchfile = fopen(argv[2], "w");
733 if (!patchfile) {
734 perror(argv[2]);
735 exit(1);
736 }
737 while (1) {
738 int len = read_one_header_line(line, sizeof(line), stdin);
739 if (!len) {
740 if (multipart_boundary[0])
741 handle_multipart_body();
742 else
743 handle_body();
744 break;
745 }
746 check_header_line(line, len);
747 }
748 return 0;
749}