webcit/html2html.c

   1 /*
   2  * Output an HTML message, modifying it slightly to make sure it plays nice
   3  * with the rest of our web framework.
   4  *
   5  * Copyright (c) 2005-2010 by the citadel.org team
   6  *
   7  * This program is open source software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 3 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  */
  20
  21 #include "webcit.h"
  22 #include "webserver.h"
  23
  24
  25 /*
  26  * Strip surrounding single or double quotes from a string.
  27  */
  28 void stripquotes(char *s)
  29 {
  30         int len;
  31
  32         if (!s) return;
  33
  34         len = strlen(s);
  35         if (len < 2) return;
  36
  37         if ( ( (s[0] == '\"') && (s[len-1] == '\"') ) || ( (s[0] == '\'') && (s[len-1] == '\'') ) ) {
  38                 s[len-1] = 0;
  39                 strcpy(s, &s[1]);
  40         }
  41 }
  42
  43
  44 /*
  45  * Check to see if a META tag has overridden the declared MIME character set.
  46  *
  47  * charset              Character set name (left unchanged if we don't do anything)
  48  * meta_http_equiv      Content of the "http-equiv" portion of the META tag
  49  * meta_content         Content of the "content" portion of the META tag
  50  */
  51 void extract_charset_from_meta(char *charset, char *meta_http_equiv, char *meta_content)
  52 {
  53         char *ptr;
  54         char buf[64];
  55
  56         if (!charset) return;
  57         if (!meta_http_equiv) return;
  58         if (!meta_content) return;
  59
  60
  61         if (strcasecmp(meta_http_equiv, "Content-type")) return;
  62
  63         ptr = strchr(meta_content, ';');
  64         if (!ptr) return;
  65
  66         safestrncpy(buf, ++ptr, sizeof buf);
  67         striplt(buf);
  68         if (!strncasecmp(buf, "charset=", 8)) {
  69                 strcpy(charset, &buf[8]);
  70
  71                 /*
  72                  * The brain-damaged webmail program in Microsoft Exchange declares
  73                  * a charset of "unicode" when they really mean "UTF-8".  GNU iconv
  74                  * treats "unicode" as an alias for "UTF-16" so we have to manually
  75                  * fix this here, otherwise messages generated in Exchange webmail
  76                  * show up as a big pile of weird characters.
  77                  */
  78                 if (!strcasecmp(charset, "unicode")) {
  79                         strcpy(charset, "UTF-8");
  80                 }
  81
  82                 /* Remove wandering punctuation */
  83                 if ((ptr=strchr(charset, '\"'))) *ptr = 0;
  84                 striplt(charset);
  85         }
  86 }
  87
  88
  89
  90 /*
  91  * Sanitize and enhance an HTML message for display.
  92  * Also convert weird character sets to UTF-8 if necessary.
  93  * Also fixup img src="cid:..." type inline images to fetch the image
  94  *
  95  */
  96 void output_html(const char *supplied_charset, int treat_as_wiki, int msgnum, StrBuf *Source, StrBuf *Target) {
  97         char buf[SIZ];
  98         char *msg;
  99         char *ptr;
 100         char *msgstart;
 101         char *msgend;
 102         StrBuf *converted_msg;
 103         int buffer_length = 1;
 104         int line_length = 0;
 105         int content_length = 0;
 106         char new_window[SIZ];
 107         int brak = 0;
 108         int alevel = 0;
 109         int scriptlevel = 0;
 110         int script_start_pos = (-1);
 111         int i;
 112         int linklen;
 113         char charset[128];
 114         StrBuf *BodyArea = NULL;
 115 #ifdef HAVE_ICONV
 116         iconv_t ic = (iconv_t)(-1) ;
 117         char *ibuf;                   /* Buffer of characters to be converted */
 118         char *obuf;                   /* Buffer for converted characters      */
 119         size_t ibuflen;               /* Length of input buffer               */
 120         size_t obuflen;               /* Length of output buffer              */
 121         char *osav;                   /* Saved pointer to output buffer       */
 122 #endif
 123         if (Target == NULL)
 124                 Target = WC->WBuf;
 125
 126         safestrncpy(charset, supplied_charset, sizeof charset);
 127         msg = strdup("");
 128         sprintf(new_window, "<a target=\"%s\" href=", TARGET);
 129
 130         if (Source == NULL) while (serv_getln(buf, sizeof buf), strcmp(buf, "000")) {
 131                 line_length = strlen(buf);
 132                 buffer_length = content_length + line_length + 2;
 133                 ptr = realloc(msg, buffer_length);
 134                 if (ptr == NULL) {
 135                         StrBufAppendPrintf(Target, "<b>");
 136                         StrBufAppendPrintf(Target, _("realloc() error! couldn't get %d bytes: %s"),
 137                                         buffer_length + 1,
 138                                         strerror(errno));
 139                         StrBufAppendPrintf(Target, "</b><br><br>\n");
 140                         while (serv_getln(buf, sizeof buf), strcmp(buf, "000")) {
 141                                 /** flush */
 142                         }
 143                         free(msg);
 144                         return;
 145                 }
 146                 msg = ptr;
 147                 strcpy(&msg[content_length], buf);
 148                 content_length += line_length;
 149                 strcpy(&msg[content_length], "\n");
 150                 content_length += 1;
 151         }
 152         else {
 153                 content_length = StrLength(Source);
 154                 free(msg);
 155                 msg = (char*) ChrPtr(Source);/* TODO: remove cast */
 156                 buffer_length = content_length;
 157         }
 158
 159         /** Do a first pass to isolate the message body */
 160         ptr = msg + 1;
 161         msgstart = msg;
 162         msgend = &msg[content_length];
 163
 164         while (ptr < msgend) {
 165
 166                 /** Advance to next tag */
 167                 ptr = strchr(ptr, '<');
 168                 if ((ptr == NULL) || (ptr >= msgend)) break;
 169                 ++ptr;
 170                 if ((ptr == NULL) || (ptr >= msgend)) break;
 171
 172                 /*
 173                  *  Look for META tags.  Some messages (particularly in
 174                  *  Asian locales) illegally declare a message's character
 175                  *  set in the HTML instead of in the MIME headers.  This
 176                  *  is wrong but we have to work around it anyway.
 177                  */
 178                 if (!strncasecmp(ptr, "META", 4)) {
 179
 180                         char *meta_start;
 181                         char *meta_end;
 182                         int meta_length;
 183                         char *meta;
 184                         char *meta_http_equiv;
 185                         char *meta_content;
 186                         char *spaceptr;
 187
 188                         meta_start = &ptr[4];
 189                         meta_end = strchr(ptr, '>');
 190                         if ((meta_end != NULL) && (meta_end <= msgend)) {
 191                                 meta_length = meta_end - meta_start + 1;
 192                                 meta = malloc(meta_length + 1);
 193                                 safestrncpy(meta, meta_start, meta_length);
 194                                 meta[meta_length] = 0;
 195                                 striplt(meta);
 196                                 if (!strncasecmp(meta, "HTTP-EQUIV=", 11)) {
 197                                         meta_http_equiv = strdup(&meta[11]);
 198                                         spaceptr = strchr(meta_http_equiv, ' ');
 199                                         if (spaceptr != NULL) {
 200                                                 *spaceptr = 0;
 201                                                 meta_content = strdup(++spaceptr);
 202                                                 if (!strncasecmp(meta_content, "content=", 8)) {
 203                                                         strcpy(meta_content, &meta_content[8]);
 204                                                         stripquotes(meta_http_equiv);
 205                                                         stripquotes(meta_content);
 206                                                         extract_charset_from_meta(charset,
 207                                                                         meta_http_equiv, meta_content);
 208                                                 }
 209                                                 free(meta_content);
 210                                         }
 211                                         free(meta_http_equiv);
 212                                 }
 213                                 free(meta);
 214                         }
 215                 }
 216
 217                 /*
 218                  * Any of these tags cause everything up to and including
 219                  * the tag to be removed.
 220                  */
 221                 if ( (!strncasecmp(ptr, "HTML", 4))
 222                                 ||(!strncasecmp(ptr, "HEAD", 4))
 223                                 ||(!strncasecmp(ptr, "/HEAD", 5))
 224                                 ||(!strncasecmp(ptr, "BODY", 4)) ) {
 225                         char *pBody = NULL;
 226
 227                         if (!strncasecmp(ptr, "BODY", 4)) {
 228                                 pBody = ptr;
 229                         }
 230                         ptr = strchr(ptr, '>');
 231                         if ((ptr == NULL) || (ptr >= msgend)) break;
 232                         if ((pBody != NULL) && (ptr - pBody > 4)) {
 233                                 char* src;
 234                                 char *cid_start, *cid_end;
 235
 236                                 *ptr = '\0';
 237                                 pBody += 4;
 238                                 while ((isspace(*pBody)) && (pBody < ptr))
 239                                         pBody ++;
 240                                 BodyArea = NewStrBufPlain(NULL,  ptr - pBody);
 241
 242                                 if (pBody < ptr) {
 243                                         src = strstr(pBody, "cid:");
 244                                         if (src) {
 245                                                 cid_start = src + 4;
 246                                                 cid_end = cid_start;
 247                                                 while ((*cid_end != '"') &&
 248                                                                 !isspace(*cid_end) &&
 249                                                                 (cid_end < ptr))
 250                                                         cid_end ++;
 251
 252                                                 /* copy tag and attributes up to src="cid: */
 253                                                 StrBufAppendBufPlain(BodyArea, pBody, src - pBody, 0);
 254
 255                                                 /* add in /webcit/mimepart/<msgno>/CID/
 256                                                    trailing / stops dumb URL filters getting excited */
 257                                                 StrBufAppendPrintf(BodyArea,
 258                                                                 "/webcit/mimepart/%d/",msgnum);
 259                                                 StrBufAppendBufPlain(BodyArea, cid_start, cid_end - cid_start, 0);
 260
 261                                                 if (ptr - cid_end > 0)
 262                                                         StrBufAppendBufPlain(BodyArea,
 263                                                                         cid_end + 1,
 264                                                                         ptr - cid_end, 0);
 265                                         }
 266                                         else
 267                                                 StrBufAppendBufPlain(BodyArea, pBody, ptr - pBody, 0);
 268                                 }
 269                                 *ptr = '>';
 270                         }
 271                         ++ptr;
 272                         if ((ptr == NULL) || (ptr >= msgend)) break;
 273                         msgstart = ptr;
 274                 }
 275
 276                 /*
 277                  * Any of these tags cause everything including and following
 278                  * the tag to be removed.
 279                  */
 280                 if ( (!strncasecmp(ptr, "/HTML", 5))
 281                                 ||(!strncasecmp(ptr, "/BODY", 5)) ) {
 282                         --ptr;
 283                         msgend = ptr;
 284                         strcpy(ptr, "");
 285
 286                 }
 287
 288                 ++ptr;
 289         }
 290         if (msgstart > msg) {
 291                 strcpy(msg, msgstart);
 292         }
 293
 294         /* Now go through the message, parsing tags as necessary. */
 295         converted_msg = NewStrBufPlain(NULL, content_length + 8192);
 296
 297
 298         /** Convert foreign character sets to UTF-8 if necessary. */
 299 #ifdef HAVE_ICONV
 300         if ( (strcasecmp(charset, "us-ascii"))
 301                         && (strcasecmp(charset, "UTF-8"))
 302                         && (strcasecmp(charset, ""))
 303            ) {
 304                 lprintf(9, "Converting %s to UTF-8\n", charset);
 305                 ctdl_iconv_open("UTF-8", charset, &ic);
 306                 if (ic == (iconv_t)(-1) ) {
 307                         lprintf(5, "%s:%d iconv_open() failed: %s\n",
 308                                         __FILE__, __LINE__, strerror(errno));
 309                 }
 310         }
 311         if  (Source == NULL) {
 312                 if (ic != (iconv_t)(-1) ) {
 313                         ibuf = msg;
 314                         ibuflen = content_length;
 315                         obuflen = content_length + (content_length / 2) ;
 316                         obuf = (char *) malloc(obuflen);
 317                         osav = obuf;
 318                         iconv(ic, &ibuf, &ibuflen, &obuf, &obuflen);
 319                         content_length = content_length + (content_length / 2) - obuflen;
 320                         osav[content_length] = 0;
 321                         free(msg);
 322                         msg = osav;
 323                         iconv_close(ic);
 324                 }
 325         }
 326         else {
 327                 if (ic != (iconv_t)(-1) ) {
 328                         StrBuf *Buf = NewStrBufPlain(NULL, StrLength(Source) + 8096);;
 329                         StrBufConvert(Source, Buf, &ic);
 330                         FreeStrBuf(&Buf);
 331                         iconv_close(ic);
 332                         msg = (char*)ChrPtr(Source); /* TODO: get rid of this. */
 333                 }
 334         }
 335
 336 #endif
 337
 338         /*
 339          *      At this point, the message has been stripped down to
 340          *      only the content inside the <BODY></BODY> tags, and has
 341          *      been converted to UTF-8 if it was originally in a foreign
 342          *      character set.  The text is also guaranteed to be null
 343          *      terminated now.
 344          */
 345
 346         if (converted_msg == NULL) {
 347                 StrBufAppendPrintf(Target, "Error %d: %s<br>%s:%d", errno, strerror(errno), __FILE__, __LINE__);
 348                 goto BAIL;
 349         }
 350
 351         if (BodyArea != NULL) {
 352                 StrBufAppendBufPlain(converted_msg, HKEY("<table "), 0);
 353                 StrBufAppendBuf(converted_msg, BodyArea, 0);
 354                 StrBufAppendBufPlain(converted_msg, HKEY(" width=\"100%\"><tr><td>"), 0);
 355         }
 356         ptr = msg;
 357         msgend = strchr(msg, 0);
 358         while (ptr < msgend) {
 359
 360                 /** Try to sanitize the html of any rogue scripts */
 361                 if (!strncasecmp(ptr, "<script", 7)) {
 362                         if (scriptlevel == 0) {
 363                                 script_start_pos = StrLength(converted_msg);
 364                         }
 365                         ++scriptlevel;
 366                 }
 367                 if (!strncasecmp(ptr, "</script", 8)) {
 368                         --scriptlevel;
 369                 }
 370
 371                 /**
 372                  * Change mailto: links to WebCit mail, by replacing the
 373                  * link with one that points back to our mail room.  Due to
 374                  * the way we parse URL's, it'll even handle mailto: links
 375                  * that have "?subject=" in them.
 376                  */
 377                 if (!strncasecmp(ptr, "<a href=\"mailto:", 16)) {
 378                         content_length += 64;
 379                         StrBufAppendPrintf(converted_msg,
 380                                         "<a href=\"display_enter?force_room=_MAIL_?recp=");
 381                         ptr = &ptr[16];
 382                         ++alevel;
 383                         ++brak;
 384                 }
 385                 /** Make external links open in a separate window */
 386                 else if (!strncasecmp(ptr, "<a href=\"", 9)) {
 387                         ++alevel;
 388                         ++brak;
 389                         if ( ((strchr(ptr, ':') < strchr(ptr, '/')))
 390                                         &&  ((strchr(ptr, '/') < strchr(ptr, '>')))
 391                            ) {
 392                                 /* open external links to new window */
 393                                 StrBufAppendPrintf(converted_msg, new_window);
 394                                 ptr = &ptr[8];
 395                         }
 396                         else if ( (treat_as_wiki) && (strncasecmp(ptr, "<a href=\"wiki?", 14)) ) {
 397                                 content_length += 64;
 398                                 StrBufAppendPrintf(converted_msg, "<a href=\"wiki?page=");
 399                                 ptr = &ptr[9];
 400                         }
 401                         else {
 402                                 StrBufAppendPrintf(converted_msg, "<a href=\"");
 403                                 ptr = &ptr[9];
 404                         }
 405                 }
 406                 /** Fixup <img src="cid:... ...> to fetch the mime part */
 407                 else if (!strncasecmp(ptr, "<img ", 5)) {
 408                         char *cid_start, *cid_end;
 409                         char* tag_end=strchr(ptr,'>');
 410                         char* src;
 411                         /* FIXME - handle this situation (maybe someone opened an <img cid...
 412                          * and then ended the message)
 413                          */
 414                         if (!tag_end) {
 415                                 lprintf(9, "tag_end is null and ptr is:\n");
 416                                 lprintf(9, "%s\n", ptr);
 417                                 lprintf(9, "Theoretical bytes remaining: %d\n", msgend - ptr);
 418                         }
 419
 420                         src=strstr(ptr, "src=\"cid:");
 421                         ++brak;
 422
 423                         if (src
 424                             && isspace(*(src-1))
 425                                 && tag_end
 426                                 && (cid_start=strchr(src,':'))
 427                                 && (cid_end=strchr(cid_start,'"'))
 428                                 && (cid_end < tag_end)
 429                         ) {
 430                                 /* copy tag and attributes up to src="cid: */
 431                                 StrBufAppendBufPlain(converted_msg, ptr, src - ptr, 0);
 432                                 cid_start++;
 433
 434                                 /* add in /webcit/mimepart/<msgno>/CID/
 435                                    trailing / stops dumb URL filters getting excited */
 436                                 StrBufAppendPrintf(converted_msg,
 437                                                 " src=\"/webcit/mimepart/%d/",msgnum);
 438                                 StrBufAppendBufPlain(converted_msg, cid_start, cid_end - cid_start, 0);
 439                                 StrBufAppendBufPlain(converted_msg, "/\"", -1, 0);
 440
 441                                 ptr = cid_end+1;
 442                         }
 443                         StrBufAppendBufPlain(converted_msg, ptr, tag_end - ptr, 0);
 444                         ptr = tag_end;
 445                 }
 446
 447                 /**
 448                  * Turn anything that looks like a URL into a real link, as long
 449                  * as it's not inside a tag already
 450                  */
 451                 else if ( (brak == 0) && (alevel == 0)
 452                      && (!strncasecmp(ptr, "http://", 7))) {
 453                                 /** Find the end of the link */
 454                                 int strlenptr;
 455                                 linklen = 0;
 456
 457                                 strlenptr = strlen(ptr);
 458                                 for (i=0; i<=strlenptr; ++i) {
 459                                         if ((ptr[i]==0)
 460                                            ||(isspace(ptr[i]))
 461                                            ||(ptr[i]==10)
 462                                            ||(ptr[i]==13)
 463                                            ||(ptr[i]=='(')
 464                                            ||(ptr[i]==')')
 465                                            ||(ptr[i]=='<')
 466                                            ||(ptr[i]=='>')
 467                                            ||(ptr[i]=='[')
 468                                            ||(ptr[i]==']')
 469                                            ||(ptr[i]=='"')
 470                                            ||(ptr[i]=='\'')
 471                                         ) linklen = i;
 472                                         /* did s.b. send us an entity? */
 473                                         if (ptr[i] == '&') {
 474                                                 if ((ptr[i+2] ==';') ||
 475                                                     (ptr[i+3] ==';') ||
 476                                                     (ptr[i+5] ==';') ||
 477                                                     (ptr[i+6] ==';') ||
 478                                                     (ptr[i+7] ==';'))
 479                                                         linklen = i;
 480                                         }
 481                                         if (linklen > 0) break;
 482                                 }
 483                                 if (linklen > 0) {
 484                                         char *ltreviewptr;
 485                                         char *nbspreviewptr;
 486                                         char linkedchar;
 487                                         int len;
 488
 489                                         len = linklen;
 490                                         linkedchar = ptr[len];
 491                                         ptr[len] = '\0';
 492                                         /* spot for some subject strings tinymce tends to give us. */
 493                                         ltreviewptr = strchr(ptr, '<');
 494                                         if (ltreviewptr != NULL) {
 495                                                 *ltreviewptr = '\0';
 496                                                 linklen = ltreviewptr - ptr;
 497                                         }
 498
 499                                         nbspreviewptr = strstr(ptr, "&nbsp;");
 500                                         if (nbspreviewptr != NULL) {
 501                                                 /* nbspreviewptr = '\0'; */
 502                                                 linklen = nbspreviewptr - ptr;
 503                                         }
 504                                         if (ltreviewptr != 0)
 505                                                 *ltreviewptr = '<';
 506
 507                                         ptr[len] = linkedchar;
 508
 509                                         content_length += (32 + linklen);
 510                                         StrBufAppendPrintf(converted_msg, "%s\"", new_window);
 511                                         StrBufAppendBufPlain(converted_msg, ptr, linklen, 0);
 512                                         StrBufAppendPrintf(converted_msg, "\">");
 513                                         StrBufAppendBufPlain(converted_msg, ptr, linklen, 0);
 514                                         ptr += linklen;
 515                                         StrBufAppendPrintf(converted_msg, "</A>");
 516                                 }
 517                 }
 518                 else {
 519                         StrBufAppendBufPlain(converted_msg, ptr, 1, 0);
 520                         ptr++;
 521                 }
 522
 523
 524                 if ((ptr >= msg) && (ptr <= msgend)) {
 525                         /*
 526                          * We need to know when we're inside a tag,
 527                          * so we don't turn things that look like URL's into
 528                          * links, when they're already links - or image sources.
 529                          */
 530                         if ((ptr > msg) && (*(ptr-1) == '<')) {
 531                                 ++brak;
 532                         }
 533                         if ((ptr > msg) && (*(ptr-1) == '>')) {
 534                                 --brak;
 535                                 if ((scriptlevel == 0) && (script_start_pos >= 0)) {
 536                                         StrBufCutRight(converted_msg, StrLength(converted_msg) - script_start_pos);
 537                                         script_start_pos = (-1);
 538                                 }
 539                         }
 540                         if (!strncasecmp(ptr, "</A>", 3)) --alevel;
 541                 }
 542         }
 543
 544         if (BodyArea != NULL) {
 545                 StrBufAppendBufPlain(converted_msg, HKEY("</td></tr></table>"), 0);
 546                 FreeStrBuf(&BodyArea);
 547         }
 548
 549         /**     uncomment these two lines to override conversion        */
 550         /**     memcpy(converted_msg, msg, content_length);             */
 551         /**     output_length = content_length;                         */
 552
 553         /** Output our big pile of markup */
 554         StrBufAppendBuf(Target, converted_msg, 0);
 555
 556 BAIL:   /** A little trailing vertical whitespace... */
 557         StrBufAppendPrintf(Target, "<br><br>\n");
 558
 559         /** Now give back the memory */
 560         FreeStrBuf(&converted_msg);
 561         if ((msg != NULL) && (Source == NULL)) free(msg);
 562 }
 563
 564
 565
 566
 567
 568
 569 /*
 570  * Look for URL's embedded in a buffer and make them linkable.  We use a
 571  * target window in order to keep the Citadel session in its own window.
 572  */
 573 void UrlizeText(StrBuf* Target, StrBuf *Source, StrBuf *WrkBuf)
 574 {
 575         int len, UrlLen, Offset, TrailerLen;
 576         const char *start, *end, *pos;
 577
 578         FlushStrBuf(Target);
 579
 580         start = NULL;
 581         len = StrLength(Source);
 582         end = ChrPtr(Source) + len;
 583         for (pos = ChrPtr(Source); (pos < end) && (start == NULL); ++pos) {
 584                 if (!strncasecmp(pos, "http://", 7))
 585                         start = pos;
 586                 else if (!strncasecmp(pos, "ftp://", 6))
 587                         start = pos;
 588         }
 589
 590         if (start == NULL) {
 591                 StrBufAppendBuf(Target, Source, 0);
 592                 return;
 593         }
 594         FlushStrBuf(WrkBuf);
 595
 596         for (pos = ChrPtr(Source) + len; pos > start; --pos) {
 597                 if (  (!isprint(*pos))
 598                    || (isspace(*pos))
 599                    || (*pos == '{')
 600                    || (*pos == '}')
 601                    || (*pos == '|')
 602                    || (*pos == '\\')
 603                    || (*pos == '^')
 604                    || (*pos == '[')
 605                    || (*pos == ']')
 606                    || (*pos == '`')
 607                    || (*pos == '<')
 608                    || (*pos == '>')
 609                    || (*pos == '(')
 610                    || (*pos == ')')
 611                 ) {
 612                         end = pos;
 613                 }
 614         }
 615
 616         UrlLen = end - start;
 617         StrBufAppendBufPlain(WrkBuf, start, UrlLen, 0);
 618
 619         Offset = start - ChrPtr(Source);
 620         if (Offset != 0)
 621                 StrBufAppendBufPlain(Target, ChrPtr(Source), Offset, 0);
 622         StrBufAppendPrintf(Target, "%ca href=%c%s%c TARGET=%c%s%c%c%s%c/A%c",
 623                            LB, QU, ChrPtr(WrkBuf), QU, QU, TARGET,
 624                            QU, RB, ChrPtr(WrkBuf), LB, RB);
 625
 626         TrailerLen = StrLength(Source) - (end - ChrPtr(Source));
 627         if (TrailerLen > 0)
 628                 StrBufAppendBufPlain(Target, end, TrailerLen, 0);
 629 }
 630
 631
 632 void url(char *buf, size_t bufsize)
 633 {
 634         int len, UrlLen, Offset, TrailerLen, outpos;
 635         char *start, *end, *pos;
 636         char urlbuf[SIZ];
 637         char outbuf[SIZ];
 638
 639         start = NULL;
 640         len = strlen(buf);
 641         if (len > bufsize) {
 642                 lprintf(1, "URL: content longer than buffer!");
 643                 return;
 644         }
 645         end = buf + len;
 646         for (pos = buf; (pos < end) && (start == NULL); ++pos) {
 647                 if (!strncasecmp(pos, "http://", 7))
 648                         start = pos;
 649                 if (!strncasecmp(pos, "ftp://", 6))
 650                         start = pos;
 651         }
 652
 653         if (start == NULL)
 654                 return;
 655
 656         for (pos = buf+len; pos > start; --pos) {
 657                 if (  (!isprint(*pos))
 658                    || (isspace(*pos))
 659                    || (*pos == '{')
 660                    || (*pos == '}')
 661                    || (*pos == '|')
 662                    || (*pos == '\\')
 663                    || (*pos == '^')
 664                    || (*pos == '[')
 665                    || (*pos == ']')
 666                    || (*pos == '`')
 667                    || (*pos == '<')
 668                    || (*pos == '>')
 669                    || (*pos == '(')
 670                    || (*pos == ')')
 671                 ) {
 672                         end = pos;
 673                 }
 674         }
 675
 676         UrlLen = end - start;
 677         if (UrlLen > sizeof(urlbuf)){
 678                 lprintf(1, "URL: content longer than buffer!");
 679                 return;
 680         }
 681         memcpy(urlbuf, start, UrlLen);
 682         urlbuf[UrlLen] = '\0';
 683
 684         Offset = start - buf;
 685         if ((Offset != 0) && (Offset < sizeof(outbuf)))
 686                 memcpy(outbuf, buf, Offset);
 687         outpos = snprintf(&outbuf[Offset], sizeof(outbuf) - Offset,
 688                           "%ca href=%c%s%c TARGET=%c%s%c%c%s%c/A%c",
 689                           LB, QU, urlbuf, QU, QU, TARGET, QU, RB, urlbuf, LB, RB);
 690         if (outpos >= sizeof(outbuf) - Offset) {
 691                 lprintf(1, "URL: content longer than buffer!");
 692                 return;
 693         }
 694
 695         TrailerLen = len - (end - start);
 696         if (TrailerLen > 0)
 697                 memcpy(outbuf + Offset + outpos, end, TrailerLen);
 698         if (Offset + outpos + TrailerLen > bufsize) {
 699                 lprintf(1, "URL: content longer than buffer!");
 700                 return;
 701         }
 702         memcpy (buf, outbuf, Offset + outpos + TrailerLen);
 703         *(buf + Offset + outpos + TrailerLen) = '\0';
 704 }
 705