tools/gpgsplit.c

   1 /* gpgsplit.c - An OpenPGP packet splitting tool
   2  * Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc.
   3  *
   4  * This file is part of GnuPG.
   5  *
   6  * GnuPG is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * GnuPG is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <config.h>
  21 #include <errno.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <ctype.h>
  26 #include <unistd.h>
  27 #include <assert.h>
  28 #include <sys/types.h>
  29 #ifdef HAVE_DOSISH_SYSTEM
  30 # include <fcntl.h> /* for setmode() */
  31 #endif
  32 #include <zlib.h>
  33 #ifdef HAVE_BZIP2
  34 #include <bzlib.h>
  35 #endif /* HAVE_BZIP2 */
  36 #if defined(__riscos__) && defined(USE_ZLIBRISCOS)
  37 # include "zlib-riscos.h"
  38 #endif
  39
  40 #define INCLUDED_BY_MAIN_MODULE 1
  41 #include "util.h"
  42 #include "openpgpdefs.h"
  43
  44 static int opt_verbose;
  45 static const char *opt_prefix = "";
  46 static int opt_uncompress;
  47 static int opt_secret_to_public;
  48 static int opt_no_split;
  49
  50 static void g10_exit( int rc );
  51 static void split_packets (const char *fname);
  52
  53
  54 enum cmd_and_opt_values {
  55   aNull = 0,
  56   oVerbose        = 'v',
  57   oPrefix       = 'p',
  58   oUncompress   = 500,
  59   oSecretToPublic,
  60   oNoSplit,
  61
  62   aTest
  63 };
  64
  65
  66 static ARGPARSE_OPTS opts[] = {
  67
  68     { 301, NULL, 0, "@Options:\n " },
  69
  70     { oVerbose, "verbose",   0, "verbose" },
  71     { oPrefix,  "prefix",    2, "|STRING|Prepend filenames with STRING" },
  72     { oUncompress, "uncompress", 0, "uncompress a packet"},
  73     { oSecretToPublic, "secret-to-public", 0, "convert secret keys to public keys"},
  74     { oNoSplit, "no-split", 0, "write to stdout and don't actually split"},
  75 {0} };
  76
  77
  78 static const char *
  79 my_strusage (int level)
  80 {
  81   const char *p;
  82   switch (level)
  83     {
  84     case 11: p = "gpgsplit (GnuPG)";
  85       break;
  86     case 13: p = VERSION; break;
  87     case 17: p = PRINTABLE_OS_NAME; break;
  88     case 19: p = "Please report bugs to <@EMAIL@>.\n"; break;
  89
  90     case 1:
  91     case 40:    p =
  92                   "Usage: gpgsplit [options] [files] (-h for help)";
  93     break;
  94     case 41:    p =
  95                   "Syntax: gpgsplit [options] [files]\n"
  96                   "Split an OpenPGP message into packets\n";
  97     break;
  98
  99     default:    p = NULL;
 100     }
 101   return p;
 102 }
 103
 104
 105
 106 int
 107 main (int argc, char **argv)
 108 {
 109   ARGPARSE_ARGS pargs;
 110
 111 #ifdef HAVE_DOSISH_SYSTEM
 112   setmode( fileno(stdin), O_BINARY );
 113   setmode( fileno(stdout), O_BINARY );
 114 #endif
 115   log_set_prefix ("gpgsplit", JNLIB_LOG_WITH_PREFIX);
 116   set_strusage (my_strusage);
 117
 118   pargs.argc = &argc;
 119   pargs.argv = &argv;
 120   pargs.flags=  1;  /* do not remove the args */
 121   while (optfile_parse( NULL, NULL, NULL, &pargs, opts))
 122     {
 123       switch (pargs.r_opt)
 124         {
 125         case oVerbose: opt_verbose = 1; break;
 126         case oPrefix: opt_prefix = pargs.r.ret_str; break;
 127         case oUncompress: opt_uncompress = 1; break;
 128         case oSecretToPublic: opt_secret_to_public = 1; break;
 129         case oNoSplit: opt_no_split = 1; break;
 130         default : pargs.err = 2; break;
 131         }
 132     }
 133
 134   if (log_get_errorcount(0))
 135     g10_exit (2);
 136
 137   if (!argc)
 138     split_packets (NULL);
 139   else
 140     {
 141       for ( ;argc; argc--, argv++)
 142         split_packets (*argv);
 143     }
 144
 145   g10_exit (0);
 146   return 0;
 147 }
 148
 149
 150 static void
 151 g10_exit (int rc)
 152 {
 153   rc = rc? rc : log_get_errorcount(0)? 2 : 0;
 154   exit(rc );
 155 }
 156
 157 static const char *
 158 pkttype_to_string (int pkttype)
 159 {
 160   const char *s;
 161
 162   switch (pkttype)
 163     {
 164     case PKT_PUBKEY_ENC    : s = "pk_enc"; break;
 165     case PKT_SIGNATURE     : s = "sig"; break;
 166     case PKT_SYMKEY_ENC    : s = "sym_enc"; break;
 167     case PKT_ONEPASS_SIG   : s = "onepass_sig"; break;
 168     case PKT_SECRET_KEY    : s = "secret_key"; break;
 169     case PKT_PUBLIC_KEY    : s = "public_key"; break;
 170     case PKT_SECRET_SUBKEY : s = "secret_subkey"; break;
 171     case PKT_COMPRESSED    :
 172       s = opt_uncompress? "uncompressed":"compressed";
 173       break;
 174     case PKT_ENCRYPTED     : s = "encrypted"; break;
 175     case PKT_MARKER            : s = "marker"; break;
 176     case PKT_PLAINTEXT     : s = "plaintext"; break;
 177     case PKT_RING_TRUST    : s = "ring_trust"; break;
 178     case PKT_USER_ID       : s = "user_id"; break;
 179     case PKT_PUBLIC_SUBKEY : s = "public_subkey"; break;
 180     case PKT_OLD_COMMENT   : s = "old_comment"; break;
 181     case PKT_ATTRIBUTE     : s = "attribute"; break;
 182     case PKT_ENCRYPTED_MDC : s = "encrypted_mdc"; break;
 183     case PKT_MDC               : s = "mdc"; break;
 184     case PKT_COMMENT       : s = "comment"; break;
 185     case PKT_GPG_CONTROL   : s = "gpg_control"; break;
 186     default: s = "unknown"; break;
 187     }
 188   return s;
 189 }
 190
 191
 192 /*
 193  * Create a new filename and a return a pointer to a statically
 194  * allocated buffer
 195  */
 196 static char *
 197 create_filename (int pkttype)
 198 {
 199   static unsigned int partno = 0;
 200   static char *name;
 201
 202   if (!name)
 203     name = xmalloc (strlen (opt_prefix) + 100 );
 204
 205   assert (pkttype < 1000 && pkttype >= 0 );
 206   partno++;
 207   sprintf (name, "%s%06u-%03d" EXTSEP_S "%.40s",
 208            opt_prefix, partno, pkttype, pkttype_to_string (pkttype));
 209   return name;
 210 }
 211
 212 static int
 213 read_u16 (FILE *fp, size_t *rn)
 214 {
 215   int c;
 216
 217   if ( (c = getc (fp)) == EOF )
 218     return -1;
 219   *rn = c << 8;
 220   if ( (c = getc (fp)) == EOF )
 221     return -1;
 222   *rn |= c;
 223   return 0;
 224 }
 225
 226 static int
 227 read_u32 (FILE *fp, unsigned long *rn)
 228 {
 229   size_t tmp;
 230
 231   if (read_u16 (fp, &tmp))
 232     return -1;
 233   *rn = tmp << 16;
 234   if (read_u16 (fp, &tmp))
 235     return -1;
 236   *rn |= tmp;
 237   return 0;
 238 }
 239
 240 static int
 241 write_old_header (FILE *fp, int pkttype, unsigned int len)
 242 {
 243   int ctb = (0x80 | ((pkttype & 15)<<2));
 244
 245   if (len < 256)
 246     ;
 247   else if (len < 65536)
 248     ctb |= 1;
 249   else
 250     ctb |= 2;
 251
 252   if ( putc ( ctb, fp) == EOF )
 253     return -1;
 254
 255   if ( (ctb & 2) )
 256     {
 257       if (putc ((len>>24), fp) == EOF)
 258         return -1;
 259       if (putc ((len>>16), fp) == EOF)
 260         return -1;
 261     }
 262   if ( (ctb & 3) )
 263     {
 264       if (putc ((len>>8), fp) == EOF)
 265         return -1;
 266     }
 267   if (putc ((len&0xff), fp) == EOF)
 268     return -1;
 269   return 0;
 270 }
 271
 272 static int
 273 write_new_header (FILE *fp, int pkttype, unsigned int len)
 274 {
 275   if ( putc ((0xc0 | (pkttype & 0x3f)), fp) == EOF )
 276     return -1;
 277
 278   if (len < 192)
 279     {
 280       if (putc (len, fp) == EOF)
 281         return -1;
 282     }
 283   else if (len < 8384)
 284     {
 285       len -= 192;
 286       if (putc ((len/256)+192, fp) == EOF)
 287         return -1;
 288       if (putc ((len%256), fp) == EOF)
 289         return -1;
 290     }
 291   else
 292     {
 293       if (putc ( 0xff, fp) == EOF)
 294         return -1;
 295       if (putc ( (len >> 24), fp) == EOF)
 296         return -1;
 297       if (putc ( (len >> 16), fp) == EOF)
 298         return -1;
 299       if (putc ( (len >> 8), fp) == EOF)
 300         return -1;
 301       if (putc ( (len & 0xff), fp) == EOF)
 302         return -1;
 303     }
 304   return 0;
 305 }
 306
 307 /* Return the length of the public key given BUF of BUFLEN with a
 308    secret key. */
 309 static int
 310 public_key_length (const unsigned char *buf, size_t buflen)
 311 {
 312   const unsigned char *s;
 313   int nmpis;
 314
 315   /*   byte version number (3 or 4)
 316        u32  creation time
 317        [u16  valid days (version 3 only)]
 318        byte algorithm
 319        n    MPIs (n and e) */
 320   if (!buflen)
 321     return 0;
 322   if (buf[0] < 2 || buf[0] > 4)
 323     return 0; /* wrong version number */
 324   if (buflen < (buf[0] == 4? 6:8))
 325     return 0;
 326   s = buf + (buf[0] == 4? 6:8);
 327   buflen -= (buf[0] == 4? 6:8);
 328   switch (s[-1])
 329     {
 330     case 1:
 331     case 2:
 332     case 3:
 333       nmpis = 2;
 334       break;
 335     case 16:
 336     case 20:
 337       nmpis = 3;
 338       break;
 339     case 17:
 340       nmpis = 4;
 341       break;
 342     default:
 343       return 0;
 344     }
 345
 346   for (; nmpis; nmpis--)
 347     {
 348       unsigned int nbits, nbytes;
 349
 350       if (buflen < 2)
 351         return 0;
 352       nbits = (s[0] << 8) | s[1];
 353       s += 2; buflen -= 2;
 354       nbytes = (nbits+7) / 8;
 355       if (buflen < nbytes)
 356         return 0;
 357       s += nbytes; buflen -= nbytes;
 358     }
 359
 360   return s - buf;
 361 }
 362
 363 static int
 364 handle_zlib(int algo,FILE *fpin,FILE *fpout)
 365 {
 366   z_stream zs;
 367   byte *inbuf, *outbuf;
 368   unsigned int inbufsize, outbufsize;
 369   int c,zinit_done, zrc, nread, count;
 370   size_t n;
 371
 372   memset (&zs, 0, sizeof zs);
 373   inbufsize = 2048;
 374   inbuf = xmalloc (inbufsize);
 375   outbufsize = 8192;
 376   outbuf = xmalloc (outbufsize);
 377   zs.avail_in = 0;
 378   zinit_done = 0;
 379
 380   do
 381     {
 382       if (zs.avail_in < inbufsize)
 383         {
 384           n = zs.avail_in;
 385           if (!n)
 386             zs.next_in = (Bytef *) inbuf;
 387           count = inbufsize - n;
 388           for (nread=0;
 389                nread < count && (c=getc (fpin)) != EOF;
 390                nread++)
 391             inbuf[n+nread] = c;
 392
 393           n += nread;
 394           if (nread < count && algo == 1)
 395             {
 396               inbuf[n] = 0xFF; /* chew dummy byte */
 397               n++;
 398             }
 399           zs.avail_in = n;
 400         }
 401       zs.next_out = (Bytef *) outbuf;
 402       zs.avail_out = outbufsize;
 403
 404       if (!zinit_done)
 405         {
 406           zrc = (algo == 1? inflateInit2 ( &zs, -13)
 407                  : inflateInit ( &zs ));
 408           if (zrc != Z_OK)
 409             {
 410               log_fatal ("zlib problem: %s\n", zs.msg? zs.msg :
 411                          zrc == Z_MEM_ERROR ? "out of core" :
 412                          zrc == Z_VERSION_ERROR ?
 413                          "invalid lib version" :
 414                          "unknown error" );
 415             }
 416           zinit_done = 1;
 417         }
 418       else
 419         {
 420 #ifdef Z_SYNC_FLUSH
 421           zrc = inflate (&zs, Z_SYNC_FLUSH);
 422 #else
 423           zrc = inflate (&zs, Z_PARTIAL_FLUSH);
 424 #endif
 425           if (zrc == Z_STREAM_END)
 426             ; /* eof */
 427           else if (zrc != Z_OK && zrc != Z_BUF_ERROR)
 428             {
 429               if (zs.msg)
 430                 log_fatal ("zlib inflate problem: %s\n", zs.msg );
 431               else
 432                 log_fatal ("zlib inflate problem: rc=%d\n", zrc );
 433             }
 434           for (n=0; n < outbufsize - zs.avail_out; n++)
 435             {
 436               if (putc (outbuf[n], fpout) == EOF )
 437                 return 1;
 438             }
 439         }
 440     }
 441   while (zrc != Z_STREAM_END && zrc != Z_BUF_ERROR);
 442   {
 443     int i;
 444
 445     fputs ("Left over bytes:", stderr);
 446     for (i=0; i < zs.avail_in; i++)
 447       fprintf (stderr, " %02X", zs.next_in[i]);
 448     putc ('\n', stderr);
 449
 450   }
 451   inflateEnd (&zs);
 452
 453   return 0;
 454 }
 455
 456 #ifdef HAVE_BZIP2
 457 static int
 458 handle_bzip2(int algo,FILE *fpin,FILE *fpout)
 459 {
 460   bz_stream bzs;
 461   byte *inbuf, *outbuf;
 462   unsigned int inbufsize, outbufsize;
 463   int c,zinit_done, zrc, nread, count;
 464   size_t n;
 465
 466   memset (&bzs, 0, sizeof bzs);
 467   inbufsize = 2048;
 468   inbuf = xmalloc (inbufsize);
 469   outbufsize = 8192;
 470   outbuf = xmalloc (outbufsize);
 471   bzs.avail_in = 0;
 472   zinit_done = 0;
 473
 474   do
 475     {
 476       if (bzs.avail_in < inbufsize)
 477         {
 478           n = bzs.avail_in;
 479           if (!n)
 480             bzs.next_in = inbuf;
 481           count = inbufsize - n;
 482           for (nread=0;
 483                nread < count && (c=getc (fpin)) != EOF;
 484                nread++)
 485             inbuf[n+nread] = c;
 486
 487           n += nread;
 488           if (nread < count && algo == 1)
 489             {
 490               inbuf[n] = 0xFF; /* chew dummy byte */
 491               n++;
 492             }
 493           bzs.avail_in = n;
 494         }
 495       bzs.next_out = outbuf;
 496       bzs.avail_out = outbufsize;
 497
 498       if (!zinit_done)
 499         {
 500           zrc = BZ2_bzDecompressInit(&bzs,0,0);
 501           if (zrc != BZ_OK)
 502             log_fatal ("bz2lib problem: %d\n",zrc);
 503           zinit_done = 1;
 504         }
 505       else
 506         {
 507           zrc = BZ2_bzDecompress(&bzs);
 508           if (zrc == BZ_STREAM_END)
 509             ; /* eof */
 510           else if (zrc != BZ_OK && zrc != BZ_PARAM_ERROR)
 511             log_fatal ("bz2lib inflate problem: %d\n", zrc );
 512           for (n=0; n < outbufsize - bzs.avail_out; n++)
 513             {
 514               if (putc (outbuf[n], fpout) == EOF )
 515                 return 1;
 516             }
 517         }
 518     }
 519   while (zrc != BZ_STREAM_END && zrc != BZ_PARAM_ERROR);
 520   BZ2_bzDecompressEnd(&bzs);
 521
 522   return 0;
 523 }
 524 #endif /* HAVE_BZIP2 */
 525
 526 /* hdr must point to a buffer large enough to hold all header bytes */
 527 static int
 528 write_part (FILE *fpin, unsigned long pktlen,
 529             int pkttype, int partial, unsigned char *hdr, size_t hdrlen)
 530 {
 531   FILE *fpout;
 532   int c, first;
 533   unsigned char *p;
 534   const char *outname = create_filename (pkttype);
 535
 536 #if defined(__riscos__) && defined(USE_ZLIBRISCOS)
 537   static int initialized = 0;
 538
 539   if (!initialized)
 540       initialized = riscos_load_module("ZLib", zlib_path, 1);
 541 #endif
 542   if (opt_no_split)
 543     fpout = stdout;
 544   else
 545     {
 546       if (opt_verbose)
 547         log_info ("writing `%s'\n", outname);
 548       fpout = fopen (outname, "wb");
 549       if (!fpout)
 550         {
 551           log_error ("error creating `%s': %s\n", outname, strerror(errno));
 552           /* stop right now, otherwise we would mess up the sequence
 553              of the part numbers */
 554           g10_exit (1);
 555         }
 556     }
 557
 558   if (opt_secret_to_public
 559       && (pkttype == PKT_SECRET_KEY || pkttype == PKT_SECRET_SUBKEY))
 560     {
 561       unsigned char *blob = xmalloc (pktlen);
 562       int i, len;
 563
 564       pkttype = pkttype == PKT_SECRET_KEY? PKT_PUBLIC_KEY:PKT_PUBLIC_SUBKEY;
 565
 566       for (i=0; i < pktlen; i++)
 567         {
 568           c = getc (fpin);
 569           if (c == EOF)
 570             goto read_error;
 571           blob[i] = c;
 572         }
 573       len = public_key_length (blob, pktlen);
 574       if (!len)
 575         {
 576           log_error ("error calcualting public key length\n");
 577           g10_exit (1);
 578         }
 579       if ( (hdr[0] & 0x40) )
 580         {
 581           if (write_new_header (fpout, pkttype, len))
 582             goto write_error;
 583         }
 584       else
 585         {
 586           if (write_old_header (fpout, pkttype, len))
 587             goto write_error;
 588         }
 589
 590       for (i=0; i < len; i++)
 591         {
 592           if ( putc (blob[i], fpout) == EOF )
 593             goto write_error;
 594         }
 595
 596       goto ready;
 597     }
 598
 599
 600   if (!opt_uncompress)
 601     {
 602       for (p=hdr; hdrlen; p++, hdrlen--)
 603         {
 604           if ( putc (*p, fpout) == EOF )
 605             goto write_error;
 606         }
 607     }
 608
 609   first = 1;
 610   while (partial)
 611     {
 612       size_t partlen;
 613
 614       if (partial == 1)
 615         { /* openpgp */
 616           if (first )
 617             {
 618               c = pktlen;
 619               assert( c >= 224 && c < 255 );
 620               first = 0;
 621             }
 622           else if ((c = getc (fpin)) == EOF )
 623             goto read_error;
 624           else
 625             hdr[hdrlen++] = c;
 626
 627           if (c < 192)
 628             {
 629               pktlen = c;
 630               partial = 0; /* (last segment may follow) */
 631             }
 632           else if (c < 224 )
 633             {
 634               pktlen = (c - 192) * 256;
 635               if ((c = getc (fpin)) == EOF)
 636                 goto read_error;
 637               hdr[hdrlen++] = c;
 638               pktlen += c + 192;
 639               partial = 0;
 640             }
 641           else if (c == 255)
 642             {
 643               if (read_u32 (fpin, &pktlen))
 644                 goto read_error;
 645               hdr[hdrlen++] = pktlen >> 24;
 646               hdr[hdrlen++] = pktlen >> 16;
 647               hdr[hdrlen++] = pktlen >> 8;
 648               hdr[hdrlen++] = pktlen;
 649               partial = 0;
 650             }
 651           else
 652             { /* next partial body length */
 653               for (p=hdr; hdrlen; p++, hdrlen--)
 654                 {
 655                   if ( putc (*p, fpout) == EOF )
 656                     goto write_error;
 657                 }
 658               partlen = 1 << (c & 0x1f);
 659               for (; partlen; partlen--)
 660                 {
 661                   if ((c = getc (fpin)) == EOF)
 662                     goto read_error;
 663                   if ( putc (c, fpout) == EOF )
 664                     goto write_error;
 665                 }
 666             }
 667         }
 668       else if (partial == 2)
 669         { /* old gnupg */
 670           assert (!pktlen);
 671           if ( read_u16 (fpin, &partlen) )
 672             goto read_error;
 673           hdr[hdrlen++] = partlen >> 8;
 674           hdr[hdrlen++] = partlen;
 675           for (p=hdr; hdrlen; p++, hdrlen--)
 676             {
 677               if ( putc (*p, fpout) == EOF )
 678                 goto write_error;
 679             }
 680           if (!partlen)
 681             partial = 0; /* end of packet */
 682           for (; partlen; partlen--)
 683             {
 684               c = getc (fpin);
 685               if (c == EOF)
 686                 goto read_error;
 687               if ( putc (c, fpout) == EOF )
 688                 goto write_error;
 689             }
 690         }
 691       else
 692         { /* compressed: read to end */
 693           pktlen = 0;
 694           partial = 0;
 695           hdrlen = 0;
 696           if (opt_uncompress)
 697             {
 698               if ((c = getc (fpin)) == EOF)
 699                 goto read_error;
 700
 701               if(c==1 || c==2)
 702                 {
 703                   if(handle_zlib(c,fpin,fpout))
 704                     goto write_error;
 705                 }
 706 #ifdef HAVE_BZIP2
 707               else if(c==3)
 708                 {
 709                   if(handle_bzip2(c,fpin,fpout))
 710                     goto write_error;
 711                 }
 712 #endif /* HAVE_BZIP2 */
 713               else
 714                 {
 715                   log_error("invalid compression algorithm (%d)\n",c);
 716                   goto read_error;
 717                 }
 718             }
 719           else
 720             {
 721               while ( (c=getc (fpin)) != EOF )
 722                 {
 723                   if ( putc (c, fpout) == EOF )
 724                     goto write_error;
 725                 }
 726             }
 727           if (!feof (fpin))
 728             goto read_error;
 729         }
 730     }
 731
 732   for (p=hdr; hdrlen; p++, hdrlen--)
 733     {
 734       if ( putc (*p, fpout) == EOF )
 735         goto write_error;
 736     }
 737
 738   /* standard packet or last segment of partial length encoded packet */
 739   for (; pktlen; pktlen--)
 740     {
 741       c = getc (fpin);
 742       if (c == EOF)
 743         goto read_error;
 744       if ( putc (c, fpout) == EOF )
 745         goto write_error;
 746     }
 747
 748  ready:
 749   if ( !opt_no_split && fclose (fpout) )
 750     log_error ("error closing `%s': %s\n", outname, strerror (errno));
 751   return 0;
 752
 753  write_error:
 754   log_error ("error writing `%s': %s\n", outname, strerror (errno));
 755   if (!opt_no_split)
 756     fclose (fpout);
 757   return 2;
 758
 759  read_error:
 760   if (!opt_no_split)
 761     {
 762       int save = errno;
 763       fclose (fpout);
 764       errno = save;
 765     }
 766   return -1;
 767 }
 768
 769
 770
 771 static int
 772 do_split (FILE *fp)
 773 {
 774   int c, ctb, pkttype;
 775   unsigned long pktlen = 0;
 776   int partial = 0;
 777   unsigned char header[20];
 778   int header_idx = 0;
 779
 780   ctb = getc (fp);
 781   if (ctb == EOF)
 782     return 3; /* ready */
 783   header[header_idx++] = ctb;
 784
 785   if (!(ctb & 0x80))
 786     {
 787       log_error("invalid CTB %02x\n", ctb );
 788       return 1;
 789     }
 790   if ( (ctb & 0x40) )
 791     { /* new CTB */
 792       pkttype =  (ctb & 0x3f);
 793       if( (c = getc (fp)) == EOF )
 794         return -1;
 795       header[header_idx++] = c;
 796
 797       if ( c < 192 )
 798         pktlen = c;
 799       else if ( c < 224 )
 800         {
 801           pktlen = (c - 192) * 256;
 802           if( (c = getc (fp)) == EOF )
 803             return -1;
 804           header[header_idx++] = c;
 805           pktlen += c + 192;
 806         }
 807       else if ( c == 255 )
 808         {
 809           if (read_u32 (fp, &pktlen))
 810             return -1;
 811           header[header_idx++] = pktlen >> 24;
 812           header[header_idx++] = pktlen >> 16;
 813           header[header_idx++] = pktlen >> 8;
 814           header[header_idx++] = pktlen;
 815         }
 816       else
 817         { /* partial body length */
 818           pktlen = c;
 819           partial = 1;
 820         }
 821     }
 822   else
 823     {
 824       int lenbytes;
 825
 826       pkttype = (ctb>>2)&0xf;
 827       lenbytes = ((ctb&3)==3)? 0 : (1<<(ctb & 3));
 828       if (!lenbytes )
 829         {
 830           pktlen = 0; /* don't know the value */
 831           if( pkttype == PKT_COMPRESSED )
 832             partial = 3;
 833           else
 834             partial = 2; /* the old GnuPG partial length encoding */
 835         }
 836       else
 837         {
 838           for ( ; lenbytes; lenbytes-- )
 839             {
 840               pktlen <<= 8;
 841               if( (c = getc (fp)) == EOF )
 842                 return -1;
 843               header[header_idx++] = c;
 844
 845               pktlen |= c;
 846             }
 847         }
 848     }
 849
 850   return write_part (fp, pktlen, pkttype, partial, header, header_idx);
 851 }
 852
 853
 854 static void
 855 split_packets (const char *fname)
 856 {
 857   FILE *fp;
 858   int rc;
 859
 860   if (!fname || !strcmp (fname, "-"))
 861     {
 862       fp = stdin;
 863       fname = "-";
 864     }
 865   else if ( !(fp = fopen (fname,"rb")) )
 866     {
 867       log_error ("can't open `%s': %s\n", fname, strerror (errno));
 868       return;
 869     }
 870
 871   while ( !(rc = do_split (fp)) )
 872     ;
 873   if ( rc > 0 )
 874     ; /* error already handled */
 875   else if ( ferror (fp) )
 876     log_error ("error reading `%s': %s\n", fname, strerror (errno));
 877   else
 878     log_error ("premature EOF while reading `%s'\n", fname );
 879
 880   if ( fp != stdin )
 881     fclose (fp);
 882 }