mailinfo.c

   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>
  11
  12 static FILE *cmitmsg, *patchfile;
  13
  14 static int keep_subject = 0;
  15 static int metainfo_utf8 = 0;
  16 static char line[1000];
  17 static char date[1000];
  18 static char name[1000];
  19 static char email[1000];
  20 static char subject[1000];
  21
  22 static enum  {
  23         TE_DONTCARE, TE_QP, TE_BASE64,
  24 } transfer_encoding;
  25 static char charset[256];
  26
  27 static char multipart_boundary[1000];
  28 static int multipart_boundary_len;
  29 static int patch_lines = 0;
  30
  31 static 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 }
  40
  41 static int handle_from(char *line)
  42 {
  43         char *at = strchr(line, '@');
  44         char *dst;
  45
  46         if (!at)
  47                 return 0;
  48
  49         /*
  50          * If we already have one email, don't take any confusing lines
  51          */
  52         if (*email && strchr(at+1, '@'))
  53                 return 0;
  54
  55         /* 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
  81         /* 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
  95         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 }
 109
 110 static int handle_date(char *line)
 111 {
 112         strcpy(date, line);
 113         return 0;
 114 }
 115
 116 static int handle_subject(char *line)
 117 {
 118         strcpy(subject, line);
 119         return 0;
 120 }
 121
 122 /* 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  */
 127
 128 static int slurp_attr(const char *line, const char *name, char *attr)
 129 {
 130         char *ends, *ap = strcasestr(line, name);
 131         size_t sz;
 132
 133         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 }
 149
 150 static 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 }
 167
 168 static 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 }
 178
 179 static 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 }
 189
 190 static int is_multipart_boundary(const char *line)
 191 {
 192         return (!memcmp(line, multipart_boundary, multipart_boundary_len));
 193 }
 194
 195 static 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
 203 #define SEEN_FROM 01
 204 #define SEEN_DATE 02
 205 #define SEEN_SUBJECT 04
 206
 207 /* First lines of body can have From:, Date:, and Subject: */
 208 static 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 }
 239
 240 static 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
 258                 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 }
 275
 276 static 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 }
 292
 293 typedef int (*header_fn_t)(char *);
 294 struct header_def {
 295         const char *name;
 296         header_fn_t func;
 297         int namelen;
 298 };
 299
 300 static void check_header(char *line, int len, struct header_def *header)
 301 {
 302         int i;
 303
 304         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 }
 317
 318 static 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 }
 328 static 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 }
 341
 342 static 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 }
 362
 363 static 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 }
 373
 374 static 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 }
 390
 391 static 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
 396         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 }
 437
 438 static 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
 446                 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 }
 464
 465 static void decode_header_bq(char *it)
 466 {
 467         char *in, *out, *ep, *cp, *sp;
 468         char outbuf[1000];
 469
 470         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 }
 519
 520 static void decode_transfer_encoding(char *line)
 521 {
 522         char *ep;
 523
 524         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 }
 537
 538 static void handle_info(void)
 539 {
 540         char *sub;
 541         static int done_info = 0;
 542
 543         if (done_info)
 544                 return;
 545
 546         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
 553         /* 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
 564 /* We are inside message body and have read line[] already.
 565  * Spit out the commit log.
 566  */
 567 static 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
 585                 /* 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
 598 /* We have done the commit message and have the first
 599  * line of the patch in line[].
 600  */
 601 static 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
 616 /* 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  */
 622 static int handle_multipart_one_part(void)
 623 {
 624         int seen = 0;
 625         int n = 0;
 626         int len;
 627
 628         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 }
 650
 651 static void handle_multipart_body(void)
 652 {
 653         int part_num = 0;
 654
 655         /* 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
 680 /* Non multipart message */
 681 static void handle_body(void)
 682 {
 683         int seen = 0;
 684
 685         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 }
 704
 705 static const char mailinfo_usage[] =
 706         "git-mailinfo [-k] [-u] msg patch <mail >info";
 707
 708 static void usage(void) {
 709         fprintf(stderr, "%s\n", mailinfo_usage);
 710         exit(1);
 711 }
 712
 713 int 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
 725         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 }