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 #include "cache.h"
  12
  13 #ifdef NO_STRCASESTR
  14 extern char *gitstrcasestr(const char *haystack, const char *needle);
  15 #endif
  16
  17 static FILE *cmitmsg, *patchfile;
  18
  19 static int keep_subject = 0;
  20 static char *metainfo_charset = NULL;
  21 static char line[1000];
  22 static char date[1000];
  23 static char name[1000];
  24 static char email[1000];
  25 static char subject[1000];
  26
  27 static enum  {
  28         TE_DONTCARE, TE_QP, TE_BASE64,
  29 } transfer_encoding;
  30 static char charset[256];
  31
  32 static char multipart_boundary[1000];
  33 static int multipart_boundary_len;
  34 static int patch_lines = 0;
  35
  36 static char *sanity_check(char *name, char *email)
  37 {
  38         int len = strlen(name);
  39         if (len < 3 || len > 60)
  40                 return email;
  41         if (strchr(name, '@') || strchr(name, '<') || strchr(name, '>'))
  42                 return email;
  43         return name;
  44 }
  45
  46 static int handle_from(char *line)
  47 {
  48         char *at = strchr(line, '@');
  49         char *dst;
  50
  51         if (!at)
  52                 return 0;
  53
  54         /*
  55          * If we already have one email, don't take any confusing lines
  56          */
  57         if (*email && strchr(at+1, '@'))
  58                 return 0;
  59
  60         /* Pick up the string around '@', possibly delimited with <>
  61          * pair; that is the email part.  White them out while copying.
  62          */
  63         while (at > line) {
  64                 char c = at[-1];
  65                 if (isspace(c))
  66                         break;
  67                 if (c == '<') {
  68                         at[-1] = ' ';
  69                         break;
  70                 }
  71                 at--;
  72         }
  73         dst = email;
  74         for (;;) {
  75                 unsigned char c = *at;
  76                 if (!c || c == '>' || isspace(c)) {
  77                         if (c == '>')
  78                                 *at = ' ';
  79                         break;
  80                 }
  81                 *at++ = ' ';
  82                 *dst++ = c;
  83         }
  84         *dst++ = 0;
  85
  86         /* The remainder is name.  It could be "John Doe <john.doe@xz>"
  87          * or "john.doe@xz (John Doe)", but we have whited out the
  88          * email part, so trim from both ends, possibly removing
  89          * the () pair at the end.
  90          */
  91         at = line + strlen(line);
  92         while (at > line) {
  93                 unsigned char c = *--at;
  94                 if (!isspace(c)) {
  95                         at[(c == ')') ? 0 : 1] = 0;
  96                         break;
  97                 }
  98         }
  99
 100         at = line;
 101         for (;;) {
 102                 unsigned char c = *at;
 103                 if (!c || !isspace(c)) {
 104                         if (c == '(')
 105                                 at++;
 106                         break;
 107                 }
 108                 at++;
 109         }
 110         at = sanity_check(at, email);
 111         strcpy(name, at);
 112         return 1;
 113 }
 114
 115 static int handle_date(char *line)
 116 {
 117         strcpy(date, line);
 118         return 0;
 119 }
 120
 121 static int handle_subject(char *line)
 122 {
 123         strcpy(subject, line);
 124         return 0;
 125 }
 126
 127 /* NOTE NOTE NOTE.  We do not claim we do full MIME.  We just attempt
 128  * to have enough heuristics to grok MIME encoded patches often found
 129  * on our mailing lists.  For example, we do not even treat header lines
 130  * case insensitively.
 131  */
 132
 133 static int slurp_attr(const char *line, const char *name, char *attr)
 134 {
 135         char *ends, *ap = strcasestr(line, name);
 136         size_t sz;
 137
 138         if (!ap) {
 139                 *attr = 0;
 140                 return 0;
 141         }
 142         ap += strlen(name);
 143         if (*ap == '"') {
 144                 ap++;
 145                 ends = "\"";
 146         }
 147         else
 148                 ends = "; \t";
 149         sz = strcspn(ap, ends);
 150         memcpy(attr, ap, sz);
 151         attr[sz] = 0;
 152         return 1;
 153 }
 154
 155 static int handle_subcontent_type(char *line)
 156 {
 157         /* We do not want to mess with boundary.  Note that we do not
 158          * handle nested multipart.
 159          */
 160         if (strcasestr(line, "boundary=")) {
 161                 fprintf(stderr, "Not handling nested multipart message.\n");
 162                 exit(1);
 163         }
 164         slurp_attr(line, "charset=", charset);
 165         if (*charset) {
 166                 int i, c;
 167                 for (i = 0; (c = charset[i]) != 0; i++)
 168                         charset[i] = tolower(c);
 169         }
 170         return 0;
 171 }
 172
 173 static int handle_content_type(char *line)
 174 {
 175         *multipart_boundary = 0;
 176         if (slurp_attr(line, "boundary=", multipart_boundary + 2)) {
 177                 memcpy(multipart_boundary, "--", 2);
 178                 multipart_boundary_len = strlen(multipart_boundary);
 179         }
 180         slurp_attr(line, "charset=", charset);
 181         return 0;
 182 }
 183
 184 static int handle_content_transfer_encoding(char *line)
 185 {
 186         if (strcasestr(line, "base64"))
 187                 transfer_encoding = TE_BASE64;
 188         else if (strcasestr(line, "quoted-printable"))
 189                 transfer_encoding = TE_QP;
 190         else
 191                 transfer_encoding = TE_DONTCARE;
 192         return 0;
 193 }
 194
 195 static int is_multipart_boundary(const char *line)
 196 {
 197         return (!memcmp(line, multipart_boundary, multipart_boundary_len));
 198 }
 199
 200 static int eatspace(char *line)
 201 {
 202         int len = strlen(line);
 203         while (len > 0 && isspace(line[len-1]))
 204                 line[--len] = 0;
 205         return len;
 206 }
 207
 208 #define SEEN_FROM 01
 209 #define SEEN_DATE 02
 210 #define SEEN_SUBJECT 04
 211
 212 /* First lines of body can have From:, Date:, and Subject: */
 213 static int handle_inbody_header(int *seen, char *line)
 214 {
 215         if (!memcmp("From:", line, 5) && isspace(line[5])) {
 216                 if (!(*seen & SEEN_FROM) && handle_from(line+6)) {
 217                         *seen |= SEEN_FROM;
 218                         return 1;
 219                 }
 220         }
 221         if (!memcmp("Date:", line, 5) && isspace(line[5])) {
 222                 if (!(*seen & SEEN_DATE)) {
 223                         handle_date(line+6);
 224                         *seen |= SEEN_DATE;
 225                         return 1;
 226                 }
 227         }
 228         if (!memcmp("Subject:", line, 8) && isspace(line[8])) {
 229                 if (!(*seen & SEEN_SUBJECT)) {
 230                         handle_subject(line+9);
 231                         *seen |= SEEN_SUBJECT;
 232                         return 1;
 233                 }
 234         }
 235         if (!memcmp("[PATCH]", line, 7) && isspace(line[7])) {
 236                 if (!(*seen & SEEN_SUBJECT)) {
 237                         handle_subject(line);
 238                         *seen |= SEEN_SUBJECT;
 239                         return 1;
 240                 }
 241         }
 242         return 0;
 243 }
 244
 245 static char *cleanup_subject(char *subject)
 246 {
 247         if (keep_subject)
 248                 return subject;
 249         for (;;) {
 250                 char *p;
 251                 int len, remove;
 252                 switch (*subject) {
 253                 case 'r': case 'R':
 254                         if (!memcmp("e:", subject+1, 2)) {
 255                                 subject +=3;
 256                                 continue;
 257                         }
 258                         break;
 259                 case ' ': case '\t': case ':':
 260                         subject++;
 261                         continue;
 262
 263                 case '[':
 264                         p = strchr(subject, ']');
 265                         if (!p) {
 266                                 subject++;
 267                                 continue;
 268                         }
 269                         len = strlen(p);
 270                         remove = p - subject;
 271                         if (remove <= len *2) {
 272                                 subject = p+1;
 273                                 continue;
 274                         }
 275                         break;
 276                 }
 277                 return subject;
 278         }
 279 }
 280
 281 static void cleanup_space(char *buf)
 282 {
 283         unsigned char c;
 284         while ((c = *buf) != 0) {
 285                 buf++;
 286                 if (isspace(c)) {
 287                         buf[-1] = ' ';
 288                         c = *buf;
 289                         while (isspace(c)) {
 290                                 int len = strlen(buf);
 291                                 memmove(buf, buf+1, len);
 292                                 c = *buf;
 293                         }
 294                 }
 295         }
 296 }
 297
 298 typedef int (*header_fn_t)(char *);
 299 struct header_def {
 300         const char *name;
 301         header_fn_t func;
 302         int namelen;
 303 };
 304
 305 static void check_header(char *line, int len, struct header_def *header)
 306 {
 307         int i;
 308
 309         if (header[0].namelen <= 0) {
 310                 for (i = 0; header[i].name; i++)
 311                         header[i].namelen = strlen(header[i].name);
 312         }
 313         for (i = 0; header[i].name; i++) {
 314                 int len = header[i].namelen;
 315                 if (!strncasecmp(line, header[i].name, len) &&
 316                     line[len] == ':' && isspace(line[len + 1])) {
 317                         header[i].func(line + len + 2);
 318                         break;
 319                 }
 320         }
 321 }
 322
 323 static void check_subheader_line(char *line, int len)
 324 {
 325         static struct header_def header[] = {
 326                 { "Content-Type", handle_subcontent_type },
 327                 { "Content-Transfer-Encoding",
 328                   handle_content_transfer_encoding },
 329                 { NULL },
 330         };
 331         check_header(line, len, header);
 332 }
 333 static void check_header_line(char *line, int len)
 334 {
 335         static struct header_def header[] = {
 336                 { "From", handle_from },
 337                 { "Date", handle_date },
 338                 { "Subject", handle_subject },
 339                 { "Content-Type", handle_content_type },
 340                 { "Content-Transfer-Encoding",
 341                   handle_content_transfer_encoding },
 342                 { NULL },
 343         };
 344         check_header(line, len, header);
 345 }
 346
 347 static int read_one_header_line(char *line, int sz, FILE *in)
 348 {
 349         int ofs = 0;
 350         while (ofs < sz) {
 351                 int peek, len;
 352                 if (fgets(line + ofs, sz - ofs, in) == NULL)
 353                         return ofs;
 354                 len = eatspace(line + ofs);
 355                 if (len == 0)
 356                         return ofs;
 357                 peek = fgetc(in); ungetc(peek, in);
 358                 if (peek == ' ' || peek == '\t') {
 359                         /* Yuck, 2822 header "folding" */
 360                         ofs += len;
 361                         continue;
 362                 }
 363                 return ofs + len;
 364         }
 365         return ofs;
 366 }
 367
 368 static unsigned hexval(int c)
 369 {
 370         if (c >= '0' && c <= '9')
 371                 return c - '0';
 372         if (c >= 'a' && c <= 'f')
 373                 return c - 'a' + 10;
 374         if (c >= 'A' && c <= 'F')
 375                 return c - 'A' + 10;
 376         return ~0;
 377 }
 378
 379 static int decode_q_segment(char *in, char *ot, char *ep)
 380 {
 381         int c;
 382         while ((c = *in++) != 0 && (in <= ep)) {
 383                 if (c == '=') {
 384                         int d = *in++;
 385                         if (d == '\n' || !d)
 386                                 break; /* drop trailing newline */
 387                         *ot++ = ((hexval(d) << 4) | hexval(*in++));
 388                 }
 389                 else
 390                         *ot++ = c;
 391         }
 392         *ot = 0;
 393         return 0;
 394 }
 395
 396 static int decode_b_segment(char *in, char *ot, char *ep)
 397 {
 398         /* Decode in..ep, possibly in-place to ot */
 399         int c, pos = 0, acc = 0;
 400
 401         while ((c = *in++) != 0 && (in <= ep)) {
 402                 if (c == '+')
 403                         c = 62;
 404                 else if (c == '/')
 405                         c = 63;
 406                 else if ('A' <= c && c <= 'Z')
 407                         c -= 'A';
 408                 else if ('a' <= c && c <= 'z')
 409                         c -= 'a' - 26;
 410                 else if ('0' <= c && c <= '9')
 411                         c -= '0' - 52;
 412                 else if (c == '=') {
 413                         /* padding is almost like (c == 0), except we do
 414                          * not output NUL resulting only from it;
 415                          * for now we just trust the data.
 416                          */
 417                         c = 0;
 418                 }
 419                 else
 420                         continue; /* garbage */
 421                 switch (pos++) {
 422                 case 0:
 423                         acc = (c << 2);
 424                         break;
 425                 case 1:
 426                         *ot++ = (acc | (c >> 4));
 427                         acc = (c & 15) << 4;
 428                         break;
 429                 case 2:
 430                         *ot++ = (acc | (c >> 2));
 431                         acc = (c & 3) << 6;
 432                         break;
 433                 case 3:
 434                         *ot++ = (acc | c);
 435                         acc = pos = 0;
 436                         break;
 437                 }
 438         }
 439         *ot = 0;
 440         return 0;
 441 }
 442
 443 static void convert_to_utf8(char *line, char *charset)
 444 {
 445         char *in, *out;
 446         size_t insize, outsize, nrc;
 447         char outbuf[4096]; /* cheat */
 448         static char latin_one[] = "latin-1";
 449         char *input_charset = *charset ? charset : latin_one;
 450         iconv_t conv = iconv_open(metainfo_charset, input_charset);
 451
 452         if (conv == (iconv_t) -1) {
 453                 static int warned_latin1_once = 0;
 454                 if (input_charset != latin_one) {
 455                         fprintf(stderr, "cannot convert from %s to %s\n",
 456                                 input_charset, metainfo_charset);
 457                         *charset = 0;
 458                 }
 459                 else if (!warned_latin1_once) {
 460                         warned_latin1_once = 1;
 461                         fprintf(stderr, "tried to convert from %s to %s, "
 462                                 "but your iconv does not work with it.\n",
 463                                 input_charset, metainfo_charset);
 464                 }
 465                 return;
 466         }
 467         in = line;
 468         insize = strlen(in);
 469         out = outbuf;
 470         outsize = sizeof(outbuf);
 471         nrc = iconv(conv, &in, &insize, &out, &outsize);
 472         iconv_close(conv);
 473         if (nrc == (size_t) -1)
 474                 return;
 475         *out = 0;
 476         strcpy(line, outbuf);
 477 }
 478
 479 static void decode_header_bq(char *it)
 480 {
 481         char *in, *out, *ep, *cp, *sp;
 482         char outbuf[1000];
 483
 484         in = it;
 485         out = outbuf;
 486         while ((ep = strstr(in, "=?")) != NULL) {
 487                 int sz, encoding;
 488                 char charset_q[256], piecebuf[256];
 489                 if (in != ep) {
 490                         sz = ep - in;
 491                         memcpy(out, in, sz);
 492                         out += sz;
 493                         in += sz;
 494                 }
 495                 /* E.g.
 496                  * ep : "=?iso-2022-jp?B?GyR...?= foo"
 497                  * ep : "=?ISO-8859-1?Q?Foo=FCbar?= baz"
 498                  */
 499                 ep += 2;
 500                 cp = strchr(ep, '?');
 501                 if (!cp)
 502                         return; /* no munging */
 503                 for (sp = ep; sp < cp; sp++)
 504                         charset_q[sp - ep] = tolower(*sp);
 505                 charset_q[cp - ep] = 0;
 506                 encoding = cp[1];
 507                 if (!encoding || cp[2] != '?')
 508                         return; /* no munging */
 509                 ep = strstr(cp + 3, "?=");
 510                 if (!ep)
 511                         return; /* no munging */
 512                 switch (tolower(encoding)) {
 513                 default:
 514                         return; /* no munging */
 515                 case 'b':
 516                         sz = decode_b_segment(cp + 3, piecebuf, ep);
 517                         break;
 518                 case 'q':
 519                         sz = decode_q_segment(cp + 3, piecebuf, ep);
 520                         break;
 521                 }
 522                 if (sz < 0)
 523                         return;
 524                 if (metainfo_charset)
 525                         convert_to_utf8(piecebuf, charset_q);
 526                 strcpy(out, piecebuf);
 527                 out += strlen(out);
 528                 in = ep + 2;
 529         }
 530         strcpy(out, in);
 531         strcpy(it, outbuf);
 532 }
 533
 534 static void decode_transfer_encoding(char *line)
 535 {
 536         char *ep;
 537
 538         switch (transfer_encoding) {
 539         case TE_QP:
 540                 ep = line + strlen(line);
 541                 decode_q_segment(line, line, ep);
 542                 break;
 543         case TE_BASE64:
 544                 ep = line + strlen(line);
 545                 decode_b_segment(line, line, ep);
 546                 break;
 547         case TE_DONTCARE:
 548                 break;
 549         }
 550 }
 551
 552 static void handle_info(void)
 553 {
 554         char *sub;
 555         static int done_info = 0;
 556
 557         if (done_info)
 558                 return;
 559
 560         done_info = 1;
 561         sub = cleanup_subject(subject);
 562         cleanup_space(name);
 563         cleanup_space(date);
 564         cleanup_space(email);
 565         cleanup_space(sub);
 566
 567         /* Unwrap inline B and Q encoding, and optionally
 568          * normalize the meta information to utf8.
 569          */
 570         decode_header_bq(name);
 571         decode_header_bq(date);
 572         decode_header_bq(email);
 573         decode_header_bq(sub);
 574         printf("Author: %s\nEmail: %s\nSubject: %s\nDate: %s\n\n",
 575                name, email, sub, date);
 576 }
 577
 578 /* We are inside message body and have read line[] already.
 579  * Spit out the commit log.
 580  */
 581 static int handle_commit_msg(void)
 582 {
 583         if (!cmitmsg)
 584                 return 0;
 585         do {
 586                 if (!memcmp("diff -", line, 6) ||
 587                     !memcmp("---", line, 3) ||
 588                     !memcmp("Index: ", line, 7))
 589                         break;
 590                 if ((multipart_boundary[0] && is_multipart_boundary(line))) {
 591                         /* We come here when the first part had only
 592                          * the commit message without any patch.  We
 593                          * pretend we have not seen this line yet, and
 594                          * go back to the loop.
 595                          */
 596                         return 1;
 597                 }
 598
 599                 /* Unwrap transfer encoding and optionally
 600                  * normalize the log message to UTF-8.
 601                  */
 602                 decode_transfer_encoding(line);
 603                 if (metainfo_charset)
 604                         convert_to_utf8(line, charset);
 605                 fputs(line, cmitmsg);
 606         } while (fgets(line, sizeof(line), stdin) != NULL);
 607         fclose(cmitmsg);
 608         cmitmsg = NULL;
 609         return 0;
 610 }
 611
 612 /* We have done the commit message and have the first
 613  * line of the patch in line[].
 614  */
 615 static void handle_patch(void)
 616 {
 617         do {
 618                 if (multipart_boundary[0] && is_multipart_boundary(line))
 619                         break;
 620                 /* Only unwrap transfer encoding but otherwise do not
 621                  * do anything.  We do *NOT* want UTF-8 conversion
 622                  * here; we are dealing with the user payload.
 623                  */
 624                 decode_transfer_encoding(line);
 625                 fputs(line, patchfile);
 626                 patch_lines++;
 627         } while (fgets(line, sizeof(line), stdin) != NULL);
 628 }
 629
 630 /* multipart boundary and transfer encoding are set up for us, and we
 631  * are at the end of the sub header.  do equivalent of handle_body up
 632  * to the next boundary without closing patchfile --- we will expect
 633  * that the first part to contain commit message and a patch, and
 634  * handle other parts as pure patches.
 635  */
 636 static int handle_multipart_one_part(void)
 637 {
 638         int seen = 0;
 639         int n = 0;
 640         int len;
 641
 642         while (fgets(line, sizeof(line), stdin) != NULL) {
 643         again:
 644                 len = eatspace(line);
 645                 n++;
 646                 if (!len)
 647                         continue;
 648                 if (is_multipart_boundary(line))
 649                         break;
 650                 if (0 <= seen && handle_inbody_header(&seen, line))
 651                         continue;
 652                 seen = -1; /* no more inbody headers */
 653                 line[len] = '\n';
 654                 handle_info();
 655                 if (handle_commit_msg())
 656                         goto again;
 657                 handle_patch();
 658                 break;
 659         }
 660         if (n == 0)
 661                 return -1;
 662         return 0;
 663 }
 664
 665 static void handle_multipart_body(void)
 666 {
 667         int part_num = 0;
 668
 669         /* Skip up to the first boundary */
 670         while (fgets(line, sizeof(line), stdin) != NULL)
 671                 if (is_multipart_boundary(line)) {
 672                         part_num = 1;
 673                         break;
 674                 }
 675         if (!part_num)
 676                 return;
 677         /* We are on boundary line.  Start slurping the subhead. */
 678         while (1) {
 679                 int len = read_one_header_line(line, sizeof(line), stdin);
 680                 if (!len) {
 681                         if (handle_multipart_one_part() < 0)
 682                                 return;
 683                 }
 684                 else
 685                         check_subheader_line(line, len);
 686         }
 687         fclose(patchfile);
 688         if (!patch_lines) {
 689                 fprintf(stderr, "No patch found\n");
 690                 exit(1);
 691         }
 692 }
 693
 694 /* Non multipart message */
 695 static void handle_body(void)
 696 {
 697         int seen = 0;
 698
 699         while (fgets(line, sizeof(line), stdin) != NULL) {
 700                 int len = eatspace(line);
 701                 if (!len)
 702                         continue;
 703                 if (0 <= seen && handle_inbody_header(&seen, line))
 704                         continue;
 705                 seen = -1; /* no more inbody headers */
 706                 line[len] = '\n';
 707                 handle_info();
 708                 handle_commit_msg();
 709                 handle_patch();
 710                 break;
 711         }
 712         fclose(patchfile);
 713         if (!patch_lines) {
 714                 fprintf(stderr, "No patch found\n");
 715                 exit(1);
 716         }
 717 }
 718
 719 static const char mailinfo_usage[] =
 720         "git-mailinfo [-k] [-u | --encoding=<encoding>] msg patch <mail >info";
 721
 722 int main(int argc, char **argv)
 723 {
 724         /* NEEDSWORK: might want to do the optional .git/ directory
 725          * discovery
 726          */
 727         git_config(git_default_config);
 728
 729         while (1 < argc && argv[1][0] == '-') {
 730                 if (!strcmp(argv[1], "-k"))
 731                         keep_subject = 1;
 732                 else if (!strcmp(argv[1], "-u"))
 733                         metainfo_charset = git_commit_encoding;
 734                 else if (!strncmp(argv[1], "--encoding=", 11))
 735                         metainfo_charset = argv[1] + 11;
 736                 else
 737                         usage(mailinfo_usage);
 738                 argc--; argv++;
 739         }
 740
 741         if (argc != 3)
 742                 usage(mailinfo_usage);
 743         cmitmsg = fopen(argv[1], "w");
 744         if (!cmitmsg) {
 745                 perror(argv[1]);
 746                 exit(1);
 747         }
 748         patchfile = fopen(argv[2], "w");
 749         if (!patchfile) {
 750                 perror(argv[2]);
 751                 exit(1);
 752         }
 753         while (1) {
 754                 int len = read_one_header_line(line, sizeof(line), stdin);
 755                 if (!len) {
 756                         if (multipart_boundary[0])
 757                                 handle_multipart_body();
 758                         else
 759                                 handle_body();
 760                         break;
 761                 }
 762                 check_header_line(line, len);
 763         }
 764         return 0;
 765 }