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 "git-compat-util.h"
  12 #include "cache.h"
  13
  14 static FILE *cmitmsg, *patchfile;
  15
  16 static int keep_subject = 0;
  17 static char *metainfo_charset = NULL;
  18 static char line[1000];
  19 static char date[1000];
  20 static char name[1000];
  21 static char email[1000];
  22 static char subject[1000];
  23
  24 static enum  {
  25         TE_DONTCARE, TE_QP, TE_BASE64,
  26 } transfer_encoding;
  27 static char charset[256];
  28
  29 static char multipart_boundary[1000];
  30 static int multipart_boundary_len;
  31 static int patch_lines = 0;
  32
  33 static char *sanity_check(char *name, char *email)
  34 {
  35         int len = strlen(name);
  36         if (len < 3 || len > 60)
  37                 return email;
  38         if (strchr(name, '@') || strchr(name, '<') || strchr(name, '>'))
  39                 return email;
  40         return name;
  41 }
  42
  43 static int bogus_from(char *line)
  44 {
  45         /* John Doe <johndoe> */
  46         char *bra, *ket, *dst, *cp;
  47
  48         /* This is fallback, so do not bother if we already have an
  49          * e-mail address.
  50          */
  51         if (*email)
  52                 return 0;
  53
  54         bra = strchr(line, '<');
  55         if (!bra)
  56                 return 0;
  57         ket = strchr(bra, '>');
  58         if (!ket)
  59                 return 0;
  60
  61         for (dst = email, cp = bra+1; cp < ket; )
  62                 *dst++ = *cp++;
  63         *dst = 0;
  64         for (cp = line; isspace(*cp); cp++)
  65                 ;
  66         for (bra--; isspace(*bra); bra--)
  67                 *bra = 0;
  68         cp = sanity_check(cp, email);
  69         strcpy(name, cp);
  70         return 1;
  71 }
  72
  73 static int handle_from(char *line)
  74 {
  75         char *at = strchr(line, '@');
  76         char *dst;
  77
  78         if (!at)
  79                 return bogus_from(line);
  80
  81         /*
  82          * If we already have one email, don't take any confusing lines
  83          */
  84         if (*email && strchr(at+1, '@'))
  85                 return 0;
  86
  87         /* Pick up the string around '@', possibly delimited with <>
  88          * pair; that is the email part.  White them out while copying.
  89          */
  90         while (at > line) {
  91                 char c = at[-1];
  92                 if (isspace(c))
  93                         break;
  94                 if (c == '<') {
  95                         at[-1] = ' ';
  96                         break;
  97                 }
  98                 at--;
  99         }
 100         dst = email;
 101         for (;;) {
 102                 unsigned char c = *at;
 103                 if (!c || c == '>' || isspace(c)) {
 104                         if (c == '>')
 105                                 *at = ' ';
 106                         break;
 107                 }
 108                 *at++ = ' ';
 109                 *dst++ = c;
 110         }
 111         *dst++ = 0;
 112
 113         /* The remainder is name.  It could be "John Doe <john.doe@xz>"
 114          * or "john.doe@xz (John Doe)", but we have whited out the
 115          * email part, so trim from both ends, possibly removing
 116          * the () pair at the end.
 117          */
 118         at = line + strlen(line);
 119         while (at > line) {
 120                 unsigned char c = *--at;
 121                 if (!isspace(c)) {
 122                         at[(c == ')') ? 0 : 1] = 0;
 123                         break;
 124                 }
 125         }
 126
 127         at = line;
 128         for (;;) {
 129                 unsigned char c = *at;
 130                 if (!c || !isspace(c)) {
 131                         if (c == '(')
 132                                 at++;
 133                         break;
 134                 }
 135                 at++;
 136         }
 137         at = sanity_check(at, email);
 138         strcpy(name, at);
 139         return 1;
 140 }
 141
 142 static int handle_date(char *line)
 143 {
 144         strcpy(date, line);
 145         return 0;
 146 }
 147
 148 static int handle_subject(char *line)
 149 {
 150         strcpy(subject, line);
 151         return 0;
 152 }
 153
 154 /* NOTE NOTE NOTE.  We do not claim we do full MIME.  We just attempt
 155  * to have enough heuristics to grok MIME encoded patches often found
 156  * on our mailing lists.  For example, we do not even treat header lines
 157  * case insensitively.
 158  */
 159
 160 static int slurp_attr(const char *line, const char *name, char *attr)
 161 {
 162         char *ends, *ap = strcasestr(line, name);
 163         size_t sz;
 164
 165         if (!ap) {
 166                 *attr = 0;
 167                 return 0;
 168         }
 169         ap += strlen(name);
 170         if (*ap == '"') {
 171                 ap++;
 172                 ends = "\"";
 173         }
 174         else
 175                 ends = "; \t";
 176         sz = strcspn(ap, ends);
 177         memcpy(attr, ap, sz);
 178         attr[sz] = 0;
 179         return 1;
 180 }
 181
 182 static int handle_subcontent_type(char *line)
 183 {
 184         /* We do not want to mess with boundary.  Note that we do not
 185          * handle nested multipart.
 186          */
 187         if (strcasestr(line, "boundary=")) {
 188                 fprintf(stderr, "Not handling nested multipart message.\n");
 189                 exit(1);
 190         }
 191         slurp_attr(line, "charset=", charset);
 192         if (*charset) {
 193                 int i, c;
 194                 for (i = 0; (c = charset[i]) != 0; i++)
 195                         charset[i] = tolower(c);
 196         }
 197         return 0;
 198 }
 199
 200 static int handle_content_type(char *line)
 201 {
 202         *multipart_boundary = 0;
 203         if (slurp_attr(line, "boundary=", multipart_boundary + 2)) {
 204                 memcpy(multipart_boundary, "--", 2);
 205                 multipart_boundary_len = strlen(multipart_boundary);
 206         }
 207         slurp_attr(line, "charset=", charset);
 208         return 0;
 209 }
 210
 211 static int handle_content_transfer_encoding(char *line)
 212 {
 213         if (strcasestr(line, "base64"))
 214                 transfer_encoding = TE_BASE64;
 215         else if (strcasestr(line, "quoted-printable"))
 216                 transfer_encoding = TE_QP;
 217         else
 218                 transfer_encoding = TE_DONTCARE;
 219         return 0;
 220 }
 221
 222 static int is_multipart_boundary(const char *line)
 223 {
 224         return (!memcmp(line, multipart_boundary, multipart_boundary_len));
 225 }
 226
 227 static int eatspace(char *line)
 228 {
 229         int len = strlen(line);
 230         while (len > 0 && isspace(line[len-1]))
 231                 line[--len] = 0;
 232         return len;
 233 }
 234
 235 #define SEEN_FROM 01
 236 #define SEEN_DATE 02
 237 #define SEEN_SUBJECT 04
 238
 239 /* First lines of body can have From:, Date:, and Subject: */
 240 static int handle_inbody_header(int *seen, char *line)
 241 {
 242         if (!memcmp("From:", line, 5) && isspace(line[5])) {
 243                 if (!(*seen & SEEN_FROM) && handle_from(line+6)) {
 244                         *seen |= SEEN_FROM;
 245                         return 1;
 246                 }
 247         }
 248         if (!memcmp("Date:", line, 5) && isspace(line[5])) {
 249                 if (!(*seen & SEEN_DATE)) {
 250                         handle_date(line+6);
 251                         *seen |= SEEN_DATE;
 252                         return 1;
 253                 }
 254         }
 255         if (!memcmp("Subject:", line, 8) && isspace(line[8])) {
 256                 if (!(*seen & SEEN_SUBJECT)) {
 257                         handle_subject(line+9);
 258                         *seen |= SEEN_SUBJECT;
 259                         return 1;
 260                 }
 261         }
 262         if (!memcmp("[PATCH]", line, 7) && isspace(line[7])) {
 263                 if (!(*seen & SEEN_SUBJECT)) {
 264                         handle_subject(line);
 265                         *seen |= SEEN_SUBJECT;
 266                         return 1;
 267                 }
 268         }
 269         return 0;
 270 }
 271
 272 static char *cleanup_subject(char *subject)
 273 {
 274         if (keep_subject)
 275                 return subject;
 276         for (;;) {
 277                 char *p;
 278                 int len, remove;
 279                 switch (*subject) {
 280                 case 'r': case 'R':
 281                         if (!memcmp("e:", subject+1, 2)) {
 282                                 subject +=3;
 283                                 continue;
 284                         }
 285                         break;
 286                 case ' ': case '\t': case ':':
 287                         subject++;
 288                         continue;
 289
 290                 case '[':
 291                         p = strchr(subject, ']');
 292                         if (!p) {
 293                                 subject++;
 294                                 continue;
 295                         }
 296                         len = strlen(p);
 297                         remove = p - subject;
 298                         if (remove <= len *2) {
 299                                 subject = p+1;
 300                                 continue;
 301                         }
 302                         break;
 303                 }
 304                 return subject;
 305         }
 306 }
 307
 308 static void cleanup_space(char *buf)
 309 {
 310         unsigned char c;
 311         while ((c = *buf) != 0) {
 312                 buf++;
 313                 if (isspace(c)) {
 314                         buf[-1] = ' ';
 315                         c = *buf;
 316                         while (isspace(c)) {
 317                                 int len = strlen(buf);
 318                                 memmove(buf, buf+1, len);
 319                                 c = *buf;
 320                         }
 321                 }
 322         }
 323 }
 324
 325 typedef int (*header_fn_t)(char *);
 326 struct header_def {
 327         const char *name;
 328         header_fn_t func;
 329         int namelen;
 330 };
 331
 332 static void check_header(char *line, int len, struct header_def *header)
 333 {
 334         int i;
 335
 336         if (header[0].namelen <= 0) {
 337                 for (i = 0; header[i].name; i++)
 338                         header[i].namelen = strlen(header[i].name);
 339         }
 340         for (i = 0; header[i].name; i++) {
 341                 int len = header[i].namelen;
 342                 if (!strncasecmp(line, header[i].name, len) &&
 343                     line[len] == ':' && isspace(line[len + 1])) {
 344                         header[i].func(line + len + 2);
 345                         break;
 346                 }
 347         }
 348 }
 349
 350 static void check_subheader_line(char *line, int len)
 351 {
 352         static struct header_def header[] = {
 353                 { "Content-Type", handle_subcontent_type },
 354                 { "Content-Transfer-Encoding",
 355                   handle_content_transfer_encoding },
 356                 { NULL },
 357         };
 358         check_header(line, len, header);
 359 }
 360 static void check_header_line(char *line, int len)
 361 {
 362         static struct header_def header[] = {
 363                 { "From", handle_from },
 364                 { "Date", handle_date },
 365                 { "Subject", handle_subject },
 366                 { "Content-Type", handle_content_type },
 367                 { "Content-Transfer-Encoding",
 368                   handle_content_transfer_encoding },
 369                 { NULL },
 370         };
 371         check_header(line, len, header);
 372 }
 373
 374 static int read_one_header_line(char *line, int sz, FILE *in)
 375 {
 376         int ofs = 0;
 377         while (ofs < sz) {
 378                 int peek, len;
 379                 if (fgets(line + ofs, sz - ofs, in) == NULL)
 380                         return ofs;
 381                 len = eatspace(line + ofs);
 382                 if (len == 0)
 383                         return ofs;
 384                 peek = fgetc(in); ungetc(peek, in);
 385                 if (peek == ' ' || peek == '\t') {
 386                         /* Yuck, 2822 header "folding" */
 387                         ofs += len;
 388                         continue;
 389                 }
 390                 return ofs + len;
 391         }
 392         return ofs;
 393 }
 394
 395 static unsigned hexval(int c)
 396 {
 397         if (c >= '0' && c <= '9')
 398                 return c - '0';
 399         if (c >= 'a' && c <= 'f')
 400                 return c - 'a' + 10;
 401         if (c >= 'A' && c <= 'F')
 402                 return c - 'A' + 10;
 403         return ~0;
 404 }
 405
 406 static int decode_q_segment(char *in, char *ot, char *ep)
 407 {
 408         int c;
 409         while ((c = *in++) != 0 && (in <= ep)) {
 410                 if (c == '=') {
 411                         int d = *in++;
 412                         if (d == '\n' || !d)
 413                                 break; /* drop trailing newline */
 414                         *ot++ = ((hexval(d) << 4) | hexval(*in++));
 415                 }
 416                 else
 417                         *ot++ = c;
 418         }
 419         *ot = 0;
 420         return 0;
 421 }
 422
 423 static int decode_b_segment(char *in, char *ot, char *ep)
 424 {
 425         /* Decode in..ep, possibly in-place to ot */
 426         int c, pos = 0, acc = 0;
 427
 428         while ((c = *in++) != 0 && (in <= ep)) {
 429                 if (c == '+')
 430                         c = 62;
 431                 else if (c == '/')
 432                         c = 63;
 433                 else if ('A' <= c && c <= 'Z')
 434                         c -= 'A';
 435                 else if ('a' <= c && c <= 'z')
 436                         c -= 'a' - 26;
 437                 else if ('0' <= c && c <= '9')
 438                         c -= '0' - 52;
 439                 else if (c == '=') {
 440                         /* padding is almost like (c == 0), except we do
 441                          * not output NUL resulting only from it;
 442                          * for now we just trust the data.
 443                          */
 444                         c = 0;
 445                 }
 446                 else
 447                         continue; /* garbage */
 448                 switch (pos++) {
 449                 case 0:
 450                         acc = (c << 2);
 451                         break;
 452                 case 1:
 453                         *ot++ = (acc | (c >> 4));
 454                         acc = (c & 15) << 4;
 455                         break;
 456                 case 2:
 457                         *ot++ = (acc | (c >> 2));
 458                         acc = (c & 3) << 6;
 459                         break;
 460                 case 3:
 461                         *ot++ = (acc | c);
 462                         acc = pos = 0;
 463                         break;
 464                 }
 465         }
 466         *ot = 0;
 467         return 0;
 468 }
 469
 470 static void convert_to_utf8(char *line, char *charset)
 471 {
 472         char *in, *out;
 473         size_t insize, outsize, nrc;
 474         char outbuf[4096]; /* cheat */
 475         static char latin_one[] = "latin1";
 476         char *input_charset = *charset ? charset : latin_one;
 477         iconv_t conv = iconv_open(metainfo_charset, input_charset);
 478
 479         if (conv == (iconv_t) -1) {
 480                 static int warned_latin1_once = 0;
 481                 if (input_charset != latin_one) {
 482                         fprintf(stderr, "cannot convert from %s to %s\n",
 483                                 input_charset, metainfo_charset);
 484                         *charset = 0;
 485                 }
 486                 else if (!warned_latin1_once) {
 487                         warned_latin1_once = 1;
 488                         fprintf(stderr, "tried to convert from %s to %s, "
 489                                 "but your iconv does not work with it.\n",
 490                                 input_charset, metainfo_charset);
 491                 }
 492                 return;
 493         }
 494         in = line;
 495         insize = strlen(in);
 496         out = outbuf;
 497         outsize = sizeof(outbuf);
 498         nrc = iconv(conv, &in, &insize, &out, &outsize);
 499         iconv_close(conv);
 500         if (nrc == (size_t) -1)
 501                 return;
 502         *out = 0;
 503         strcpy(line, outbuf);
 504 }
 505
 506 static void decode_header_bq(char *it)
 507 {
 508         char *in, *out, *ep, *cp, *sp;
 509         char outbuf[1000];
 510
 511         in = it;
 512         out = outbuf;
 513         while ((ep = strstr(in, "=?")) != NULL) {
 514                 int sz, encoding;
 515                 char charset_q[256], piecebuf[256];
 516                 if (in != ep) {
 517                         sz = ep - in;
 518                         memcpy(out, in, sz);
 519                         out += sz;
 520                         in += sz;
 521                 }
 522                 /* E.g.
 523                  * ep : "=?iso-2022-jp?B?GyR...?= foo"
 524                  * ep : "=?ISO-8859-1?Q?Foo=FCbar?= baz"
 525                  */
 526                 ep += 2;
 527                 cp = strchr(ep, '?');
 528                 if (!cp)
 529                         return; /* no munging */
 530                 for (sp = ep; sp < cp; sp++)
 531                         charset_q[sp - ep] = tolower(*sp);
 532                 charset_q[cp - ep] = 0;
 533                 encoding = cp[1];
 534                 if (!encoding || cp[2] != '?')
 535                         return; /* no munging */
 536                 ep = strstr(cp + 3, "?=");
 537                 if (!ep)
 538                         return; /* no munging */
 539                 switch (tolower(encoding)) {
 540                 default:
 541                         return; /* no munging */
 542                 case 'b':
 543                         sz = decode_b_segment(cp + 3, piecebuf, ep);
 544                         break;
 545                 case 'q':
 546                         sz = decode_q_segment(cp + 3, piecebuf, ep);
 547                         break;
 548                 }
 549                 if (sz < 0)
 550                         return;
 551                 if (metainfo_charset)
 552                         convert_to_utf8(piecebuf, charset_q);
 553                 strcpy(out, piecebuf);
 554                 out += strlen(out);
 555                 in = ep + 2;
 556         }
 557         strcpy(out, in);
 558         strcpy(it, outbuf);
 559 }
 560
 561 static void decode_transfer_encoding(char *line)
 562 {
 563         char *ep;
 564
 565         switch (transfer_encoding) {
 566         case TE_QP:
 567                 ep = line + strlen(line);
 568                 decode_q_segment(line, line, ep);
 569                 break;
 570         case TE_BASE64:
 571                 ep = line + strlen(line);
 572                 decode_b_segment(line, line, ep);
 573                 break;
 574         case TE_DONTCARE:
 575                 break;
 576         }
 577 }
 578
 579 static void handle_info(void)
 580 {
 581         char *sub;
 582         static int done_info = 0;
 583
 584         if (done_info)
 585                 return;
 586
 587         done_info = 1;
 588         sub = cleanup_subject(subject);
 589         cleanup_space(name);
 590         cleanup_space(date);
 591         cleanup_space(email);
 592         cleanup_space(sub);
 593
 594         /* Unwrap inline B and Q encoding, and optionally
 595          * normalize the meta information to utf8.
 596          */
 597         decode_header_bq(name);
 598         decode_header_bq(date);
 599         decode_header_bq(email);
 600         decode_header_bq(sub);
 601         printf("Author: %s\nEmail: %s\nSubject: %s\nDate: %s\n\n",
 602                name, email, sub, date);
 603 }
 604
 605 /* We are inside message body and have read line[] already.
 606  * Spit out the commit log.
 607  */
 608 static int handle_commit_msg(void)
 609 {
 610         if (!cmitmsg)
 611                 return 0;
 612         do {
 613                 if (!memcmp("diff -", line, 6) ||
 614                     !memcmp("---", line, 3) ||
 615                     !memcmp("Index: ", line, 7))
 616                         break;
 617                 if ((multipart_boundary[0] && is_multipart_boundary(line))) {
 618                         /* We come here when the first part had only
 619                          * the commit message without any patch.  We
 620                          * pretend we have not seen this line yet, and
 621                          * go back to the loop.
 622                          */
 623                         return 1;
 624                 }
 625
 626                 /* Unwrap transfer encoding and optionally
 627                  * normalize the log message to UTF-8.
 628                  */
 629                 decode_transfer_encoding(line);
 630                 if (metainfo_charset)
 631                         convert_to_utf8(line, charset);
 632                 fputs(line, cmitmsg);
 633         } while (fgets(line, sizeof(line), stdin) != NULL);
 634         fclose(cmitmsg);
 635         cmitmsg = NULL;
 636         return 0;
 637 }
 638
 639 /* We have done the commit message and have the first
 640  * line of the patch in line[].
 641  */
 642 static void handle_patch(void)
 643 {
 644         do {
 645                 if (multipart_boundary[0] && is_multipart_boundary(line))
 646                         break;
 647                 /* Only unwrap transfer encoding but otherwise do not
 648                  * do anything.  We do *NOT* want UTF-8 conversion
 649                  * here; we are dealing with the user payload.
 650                  */
 651                 decode_transfer_encoding(line);
 652                 fputs(line, patchfile);
 653                 patch_lines++;
 654         } while (fgets(line, sizeof(line), stdin) != NULL);
 655 }
 656
 657 /* multipart boundary and transfer encoding are set up for us, and we
 658  * are at the end of the sub header.  do equivalent of handle_body up
 659  * to the next boundary without closing patchfile --- we will expect
 660  * that the first part to contain commit message and a patch, and
 661  * handle other parts as pure patches.
 662  */
 663 static int handle_multipart_one_part(void)
 664 {
 665         int seen = 0;
 666         int n = 0;
 667         int len;
 668
 669         while (fgets(line, sizeof(line), stdin) != NULL) {
 670         again:
 671                 len = eatspace(line);
 672                 n++;
 673                 if (!len)
 674                         continue;
 675                 if (is_multipart_boundary(line))
 676                         break;
 677                 if (0 <= seen && handle_inbody_header(&seen, line))
 678                         continue;
 679                 seen = -1; /* no more inbody headers */
 680                 line[len] = '\n';
 681                 handle_info();
 682                 if (handle_commit_msg())
 683                         goto again;
 684                 handle_patch();
 685                 break;
 686         }
 687         if (n == 0)
 688                 return -1;
 689         return 0;
 690 }
 691
 692 static void handle_multipart_body(void)
 693 {
 694         int part_num = 0;
 695
 696         /* Skip up to the first boundary */
 697         while (fgets(line, sizeof(line), stdin) != NULL)
 698                 if (is_multipart_boundary(line)) {
 699                         part_num = 1;
 700                         break;
 701                 }
 702         if (!part_num)
 703                 return;
 704         /* We are on boundary line.  Start slurping the subhead. */
 705         while (1) {
 706                 int len = read_one_header_line(line, sizeof(line), stdin);
 707                 if (!len) {
 708                         if (handle_multipart_one_part() < 0)
 709                                 return;
 710                 }
 711                 else
 712                         check_subheader_line(line, len);
 713         }
 714         fclose(patchfile);
 715         if (!patch_lines) {
 716                 fprintf(stderr, "No patch found\n");
 717                 exit(1);
 718         }
 719 }
 720
 721 /* Non multipart message */
 722 static void handle_body(void)
 723 {
 724         int seen = 0;
 725
 726         while (fgets(line, sizeof(line), stdin) != NULL) {
 727                 int len = eatspace(line);
 728                 if (!len)
 729                         continue;
 730                 if (0 <= seen && handle_inbody_header(&seen, line))
 731                         continue;
 732                 seen = -1; /* no more inbody headers */
 733                 line[len] = '\n';
 734                 handle_info();
 735                 handle_commit_msg();
 736                 handle_patch();
 737                 break;
 738         }
 739         fclose(patchfile);
 740         if (!patch_lines) {
 741                 fprintf(stderr, "No patch found\n");
 742                 exit(1);
 743         }
 744 }
 745
 746 static const char mailinfo_usage[] =
 747         "git-mailinfo [-k] [-u | --encoding=<encoding>] msg patch <mail >info";
 748
 749 int main(int argc, char **argv)
 750 {
 751         /* NEEDSWORK: might want to do the optional .git/ directory
 752          * discovery
 753          */
 754         git_config(git_default_config);
 755
 756         while (1 < argc && argv[1][0] == '-') {
 757                 if (!strcmp(argv[1], "-k"))
 758                         keep_subject = 1;
 759                 else if (!strcmp(argv[1], "-u"))
 760                         metainfo_charset = git_commit_encoding;
 761                 else if (!strncmp(argv[1], "--encoding=", 11))
 762                         metainfo_charset = argv[1] + 11;
 763                 else
 764                         usage(mailinfo_usage);
 765                 argc--; argv++;
 766         }
 767
 768         if (argc != 3)
 769                 usage(mailinfo_usage);
 770         cmitmsg = fopen(argv[1], "w");
 771         if (!cmitmsg) {
 772                 perror(argv[1]);
 773                 exit(1);
 774         }
 775         patchfile = fopen(argv[2], "w");
 776         if (!patchfile) {
 777                 perror(argv[2]);
 778                 exit(1);
 779         }
 780         while (1) {
 781                 int len = read_one_header_line(line, sizeof(line), stdin);
 782                 if (!len) {
 783                         if (multipart_boundary[0])
 784                                 handle_multipart_body();
 785                         else
 786                                 handle_body();
 787                         break;
 788                 }
 789                 check_header_line(line, len);
 790         }
 791         return 0;
 792 }