webcit/mime_parser.c

   1 /*
   2  * $Id$
   3  *
   4  * This is the MIME parser for Citadel.  Sometimes it actually works.
   5  *
   6  * Copyright (c) 1998-2003 by Art Cancro
   7  * This code is distributed under the terms of the GNU General Public License.
   8  *
   9  */
  10
  11
  12 #include <stdlib.h>
  13 #include <unistd.h>
  14 #include <stdio.h>
  15 #include <signal.h>
  16 #include <sys/types.h>
  17 #include <ctype.h>
  18 #include <string.h>
  19 #include <sys/stat.h>
  20 #include <errno.h>
  21
  22 #include "webcit.h"
  23
  24 #include "mime_parser.h"
  25
  26
  27 void extract_key(char *target, char *source, char *key)
  28 {
  29         int a, b;
  30
  31         strcpy(target, source);
  32         for (a = 0; a < strlen(target); ++a) {
  33                 if ((!strncasecmp(&target[a], key, strlen(key)))
  34                     && (target[a + strlen(key)] == '=')) {
  35                         strcpy(target, &target[a + strlen(key) + 1]);
  36                         if (target[0] == 34)
  37                                 strcpy(target, &target[1]);
  38                         for (b = 0; b < strlen(target); ++b)
  39                                 if (target[b] == 34)
  40                                         target[b] = 0;
  41                         return;
  42                 }
  43         }
  44         strcpy(target, "");
  45 }
  46
  47
  48 /*
  49  * For non-multipart messages, we need to generate a quickie partnum of "1"
  50  * to return to callback functions.  Some callbacks demand it.
  51  */
  52 char *fixed_partnum(char *supplied_partnum) {
  53         if (supplied_partnum == NULL) return "1";
  54         if (strlen(supplied_partnum)==0) return "1";
  55         return supplied_partnum;
  56 }
  57
  58
  59
  60 /*
  61  * Convert "quoted-printable" to binary.  Returns number of bytes decoded.
  62  */
  63 int CtdlDecodeQuotedPrintable(char *decoded, char *encoded, int sourcelen) {
  64         char buf[SIZ];
  65         int buf_length = 0;
  66         int soft_line_break = 0;
  67         int ch;
  68         int decoded_length = 0;
  69         int i;
  70
  71         decoded[0] = 0;
  72         decoded_length = 0;
  73         buf[0] = 0;
  74         buf_length = 0;
  75
  76         for (i = 0; i < sourcelen; ++i) {
  77
  78                 buf[buf_length++] = encoded[i];
  79
  80                 if ( (encoded[i] == '\n')
  81                    || (encoded[i] == 0)
  82                    || (i == (sourcelen-1)) ) {
  83                         buf[buf_length++] = 0;
  84
  85                         /*** begin -- process one line ***/
  86
  87                         if (buf[strlen(buf)-1] == '\n') {
  88                                 buf[strlen(buf)-1] = 0;
  89                         }
  90                         if (buf[strlen(buf)-1] == '\r') {
  91                                 buf[strlen(buf)-1] = 0;
  92                         }
  93                         while (isspace(buf[strlen(buf)-1])) {
  94                                 buf[strlen(buf)-1] = 0;
  95                         }
  96                         soft_line_break = 0;
  97
  98                         while (strlen(buf) > 0) {
  99                                 if (!strcmp(buf, "=")) {
 100                                         soft_line_break = 1;
 101                                         strcpy(buf, "");
 102                                 } else if ((strlen(buf)>=3) && (buf[0]=='=')) {
 103                                         sscanf(&buf[1], "%02x", &ch);
 104                                         decoded[decoded_length++] = ch;
 105                                         strcpy(buf, &buf[3]);
 106                                 } else {
 107                                         decoded[decoded_length++] = buf[0];
 108                                         strcpy(buf, &buf[1]);
 109                                 }
 110                         }
 111                         if (soft_line_break == 0) {
 112                                 decoded[decoded_length++] = '\r';
 113                                 decoded[decoded_length++] = '\n';
 114                         }
 115                         buf_length = 0;
 116                         /*** end -- process one line ***/
 117                 }
 118         }
 119
 120         decoded[decoded_length++] = 0;
 121         return(decoded_length);
 122 }
 123
 124 /*
 125  * Given a message or message-part body and a length, handle any necessary
 126  * decoding and pass the request up the stack.
 127  */
 128 void mime_decode(char *partnum,
 129                  char *part_start, size_t length,
 130                  char *content_type, char *encoding,
 131                  char *disposition,
 132                  char *name, char *filename,
 133                  void (*CallBack)
 134                   (char *cbname,
 135                    char *cbfilename,
 136                    char *cbpartnum,
 137                    char *cbdisp,
 138                    void *cbcontent,
 139                    char *cbtype,
 140                    size_t cblength,
 141                    char *cbencoding,
 142                    void *cbuserdata),
 143                  void (*PreMultiPartCallBack)
 144                   (char *cbname,
 145                    char *cbfilename,
 146                    char *cbpartnum,
 147                    char *cbdisp,
 148                    void *cbcontent,
 149                    char *cbtype,
 150                    size_t cblength,
 151                    char *cbencoding,
 152                    void *cbuserdata),
 153                  void (*PostMultiPartCallBack)
 154                   (char *cbname,
 155                    char *cbfilename,
 156                    char *cbpartnum,
 157                    char *cbdisp,
 158                    void *cbcontent,
 159                    char *cbtype,
 160                    size_t cblength,
 161                    char *cbencoding,
 162                    void *cbuserdata),
 163                   void *userdata,
 164                   int dont_decode
 165 )
 166 {
 167
 168         char *decoded;
 169         size_t bytes_decoded = 0;
 170
 171         /* Some encodings aren't really encodings */
 172         if (!strcasecmp(encoding, "7bit"))
 173                 strcpy(encoding, "");
 174         if (!strcasecmp(encoding, "8bit"))
 175                 strcpy(encoding, "");
 176         if (!strcasecmp(encoding, "binary"))
 177                 strcpy(encoding, "");
 178
 179         /* If this part is not encoded, send as-is */
 180         if ( (strlen(encoding) == 0) || (dont_decode)) {
 181                 if (CallBack != NULL) {
 182                         CallBack(name, filename, fixed_partnum(partnum),
 183                                 disposition, part_start,
 184                                 content_type, length, encoding, userdata);
 185                         }
 186                 return;
 187         }
 188
 189         if ((strcasecmp(encoding, "base64"))
 190             && (strcasecmp(encoding, "quoted-printable"))) {
 191                 return;
 192         }
 193         /*
 194          * Allocate a buffer for the decoded data.  The output buffer is the
 195          * same size as the input buffer; this assumes that the decoded data
 196          * will never be larger than the encoded data.  This is a safe
 197          * assumption with base64, uuencode, and quoted-printable.
 198          */
 199         decoded = mallok(length+2048);
 200         if (decoded == NULL) {
 201                 return;
 202         }
 203
 204         if (!strcasecmp(encoding, "base64")) {
 205                 bytes_decoded = CtdlDecodeBase64(decoded, part_start, length);
 206         }
 207         else if (!strcasecmp(encoding, "quoted-printable")) {
 208                 bytes_decoded = CtdlDecodeQuotedPrintable(decoded,
 209                                                         part_start, length);
 210         }
 211
 212         if (bytes_decoded > 0) if (CallBack != NULL) {
 213                 CallBack(name, filename, fixed_partnum(partnum),
 214                         disposition, decoded,
 215                         content_type, bytes_decoded, "binary", userdata);
 216         }
 217
 218         phree(decoded);
 219 }
 220
 221 /*
 222  * Break out the components of a multipart message
 223  * (This function expects to be fed HEADERS + CONTENT)
 224  * Note: NULL can be supplied as content_end; in this case, the message is
 225  * considered to have ended when the parser encounters a 0x00 byte.
 226  */
 227 void the_mime_parser(char *partnum,
 228                      char *content_start, char *content_end,
 229                      void (*CallBack)
 230                       (char *cbname,
 231                        char *cbfilename,
 232                        char *cbpartnum,
 233                        char *cbdisp,
 234                        void *cbcontent,
 235                        char *cbtype,
 236                        size_t cblength,
 237                        char *cbencoding,
 238                        void *cbuserdata),
 239                      void (*PreMultiPartCallBack)
 240                       (char *cbname,
 241                        char *cbfilename,
 242                        char *cbpartnum,
 243                        char *cbdisp,
 244                        void *cbcontent,
 245                        char *cbtype,
 246                        size_t cblength,
 247                        char *cbencoding,
 248                        void *cbuserdata),
 249                      void (*PostMultiPartCallBack)
 250                       (char *cbname,
 251                        char *cbfilename,
 252                        char *cbpartnum,
 253                        char *cbdisp,
 254                        void *cbcontent,
 255                        char *cbtype,
 256                        size_t cblength,
 257                        char *cbencoding,
 258                        void *cbuserdata),
 259                       void *userdata,
 260                       int dont_decode
 261 )
 262 {
 263
 264         char *ptr;
 265         char *part_start, *part_end = NULL;
 266         char buf[SIZ];
 267         char *header;
 268         char *boundary;
 269         char *startary;
 270         char *endary;
 271         char *content_type;
 272         size_t content_length;
 273         char *encoding;
 274         char *disposition;
 275         char *name = NULL;
 276         char *content_type_name;
 277         char *content_disposition_name;
 278         char *filename;
 279         int is_multipart;
 280         int part_seq = 0;
 281         int i;
 282         size_t length;
 283         char nested_partnum[SIZ];
 284
 285         ptr = content_start;
 286         content_length = 0;
 287
 288         boundary = mallok(SIZ);
 289         memset(boundary, 0, SIZ);
 290
 291         startary = mallok(SIZ);
 292         memset(startary, 0, SIZ);
 293
 294         endary = mallok(SIZ);
 295         memset(endary, 0, SIZ);
 296
 297         header = mallok(SIZ);
 298         memset(header, 0, SIZ);
 299
 300         content_type = mallok(SIZ);
 301         memset(content_type, 0, SIZ);
 302
 303         encoding = mallok(SIZ);
 304         memset(encoding, 0, SIZ);
 305
 306         content_type_name = mallok(SIZ);
 307         memset(content_type_name, 0, SIZ);
 308
 309         content_disposition_name = mallok(SIZ);
 310         memset(content_disposition_name, 0, SIZ);
 311
 312         filename = mallok(SIZ);
 313         memset(filename, 0, SIZ);
 314
 315         disposition = mallok(SIZ);
 316         memset(disposition, 0, SIZ);
 317
 318         /* If the caller didn't supply an endpointer, generate one by measure */
 319         if (content_end == NULL) {
 320                 content_end = &content_start[strlen(content_start)];
 321         }
 322
 323         /* Learn interesting things from the headers */
 324         strcpy(header, "");
 325         do {
 326                 ptr = memreadline(ptr, buf, SIZ);
 327                 if (ptr >= content_end) {
 328                         goto end_parser;
 329                 }
 330
 331                 for (i = 0; i < strlen(buf); ++i)
 332                         if (isspace(buf[i]))
 333                                 buf[i] = ' ';
 334                 if (!isspace(buf[0])) {
 335                         if (!strncasecmp(header, "Content-type: ", 14)) {
 336                                 strcpy(content_type, &header[14]);
 337                                 extract_key(content_type_name, content_type, "name");
 338                                 /* Deal with weird headers */
 339                                 if (strchr(content_type, ' '))
 340                                         *(strchr(content_type, ' ')) = '\0';
 341                                 if (strchr(content_type, ';'))
 342                                         *(strchr(content_type, ';')) = '\0';
 343                         }
 344                         if (!strncasecmp(header, "Content-Disposition: ", 21)) {
 345                                 strcpy(disposition, &header[21]);
 346                                 extract_key(content_disposition_name, disposition, "name");
 347                                 extract_key(filename, disposition, "filename");
 348                         }
 349                         if (!strncasecmp(header, "Content-length: ", 16)) {
 350                                 content_length = (size_t) atol(&header[16]);
 351                         }
 352                         if (!strncasecmp(header,
 353                                       "Content-transfer-encoding: ", 27))
 354                                 strcpy(encoding, &header[27]);
 355                         if (strlen(boundary) == 0)
 356                                 extract_key(boundary, header, "boundary");
 357                         strcpy(header, "");
 358                 }
 359                 if ((strlen(header) + strlen(buf) + 2) < SIZ)
 360                         strcat(header, buf);
 361         } while ((strlen(buf) > 0) && (*ptr != 0));
 362
 363         if (strchr(disposition, ';'))
 364                 *(strchr(disposition, ';')) = '\0';
 365         striplt(disposition);
 366         if (strchr(content_type, ';'))
 367                 *(strchr(content_type, ';')) = '\0';
 368         striplt(content_type);
 369
 370         if (strlen(boundary) > 0) {
 371                 is_multipart = 1;
 372         } else {
 373                 is_multipart = 0;
 374         }
 375
 376         /* If this is a multipart message, then recursively process it */
 377         part_start = NULL;
 378         if (is_multipart) {
 379
 380                 /* Tell the client about this message's multipartedness */
 381                 if (PreMultiPartCallBack != NULL) {
 382                         PreMultiPartCallBack("", "", partnum, "",
 383                                 NULL, content_type,
 384                                 0, encoding, userdata);
 385                 }
 386
 387                 /* Figure out where the boundaries are */
 388                 snprintf(startary, SIZ, "--%s", boundary);
 389                 snprintf(endary, SIZ, "--%s--", boundary);
 390                 do {
 391                         if ( (!strncasecmp(ptr, startary, strlen(startary)))
 392                            || (!strncasecmp(ptr, endary, strlen(endary))) ) {
 393                                 if (part_start != NULL) {
 394                                         if (strlen(partnum) > 0) {
 395                                                 snprintf(nested_partnum,
 396                                                          sizeof nested_partnum,
 397                                                          "%s.%d", partnum,
 398                                                          ++part_seq);
 399                                         }
 400                                         else {
 401                                                 snprintf(nested_partnum,
 402                                                          sizeof nested_partnum,
 403                                                          "%d", ++part_seq);
 404                                         }
 405                                         the_mime_parser(nested_partnum,
 406                                                     part_start, part_end,
 407                                                         CallBack,
 408                                                         PreMultiPartCallBack,
 409                                                         PostMultiPartCallBack,
 410                                                         userdata,
 411                                                         dont_decode);
 412                                 }
 413                                 ptr = memreadline(ptr, buf, SIZ);
 414                                 part_start = ptr;
 415                         }
 416                         else {
 417                                 part_end = ptr;
 418                                 ++ptr;
 419                         }
 420                         /* If we pass out of scope in the MIME multipart (by
 421                          * hitting the end boundary), force the pointer out
 422                          * of scope so this loop ends.
 423                          */
 424                         if (ptr < content_end) {
 425                                 if (!strcasecmp(ptr, endary)) {
 426                                         ptr = content_end++;
 427                                 }
 428                         }
 429                 } while (ptr <= content_end);
 430                 if (PostMultiPartCallBack != NULL) {
 431                         PostMultiPartCallBack("", "", partnum, "", NULL,
 432                                 content_type, 0, encoding, userdata);
 433                 }
 434                 goto end_parser;
 435         }
 436
 437         /* If it's not a multipart message, then do something with it */
 438         if (!is_multipart) {
 439                 part_start = ptr;
 440                 length = 0;
 441                 while (ptr < content_end) {
 442                         ++ptr;
 443                         ++length;
 444                 }
 445                 part_end = content_end;
 446                 /* fix an off-by-one error */
 447                 --part_end;
 448                 --length;
 449
 450                 /* Truncate if the header told us to */
 451                 if ( (content_length > 0) && (length > content_length) ) {
 452                         length = content_length;
 453                 }
 454
 455                 /* Sometimes the "name" field is tacked on to Content-type,
 456                  * and sometimes it's tacked on to Content-disposition.  Use
 457                  * whichever one we have.
 458                  */
 459                 if (strlen(content_disposition_name) > strlen(content_type_name)) {
 460                         name = content_disposition_name;
 461                 }
 462                 else {
 463                         name = content_type_name;
 464                 }
 465
 466                 mime_decode(partnum,
 467                             part_start, length,
 468                             content_type, encoding, disposition,
 469                             name, filename,
 470                             CallBack, NULL, NULL,
 471                             userdata, dont_decode);
 472         }
 473
 474 end_parser:     /* free the buffers!  end the oppression!! */
 475         phree(boundary);
 476         phree(startary);
 477         phree(endary);
 478         phree(header);
 479         phree(content_type);
 480         phree(encoding);
 481         phree(content_type_name);
 482         phree(content_disposition_name);
 483         phree(filename);
 484         phree(disposition);
 485 }
 486
 487
 488
 489 /*
 490  * Entry point for the MIME parser.
 491  * (This function expects to be fed HEADERS + CONTENT)
 492  * Note: NULL can be supplied as content_end; in this case, the message is
 493  * considered to have ended when the parser encounters a 0x00 byte.
 494  */
 495 void mime_parser(char *content_start,
 496                 char *content_end,
 497
 498                  void (*CallBack)
 499                   (char *cbname,
 500                    char *cbfilename,
 501                    char *cbpartnum,
 502                    char *cbdisp,
 503                    void *cbcontent,
 504                    char *cbtype,
 505                    size_t cblength,
 506                    char *cbencoding,
 507                    void *cbuserdata),
 508
 509                  void (*PreMultiPartCallBack)
 510                   (char *cbname,
 511                    char *cbfilename,
 512                    char *cbpartnum,
 513                    char *cbdisp,
 514                    void *cbcontent,
 515                    char *cbtype,
 516                    size_t cblength,
 517                    char *cbencoding,
 518                    void *cbuserdata),
 519
 520                  void (*PostMultiPartCallBack)
 521                   (char *cbname,
 522                    char *cbfilename,
 523                    char *cbpartnum,
 524                    char *cbdisp,
 525                    void *cbcontent,
 526                    char *cbtype,
 527                    size_t cblength,
 528                    char *cbencoding,
 529                    void *cbuserdata),
 530
 531                   void *userdata,
 532                   int dont_decode
 533 )
 534 {
 535
 536         the_mime_parser("", content_start, content_end,
 537                         CallBack,
 538                         PreMultiPartCallBack,
 539                         PostMultiPartCallBack,
 540                         userdata, dont_decode);
 541 }
 542