gnupg/tools/gpgsplit.c

/* gpgsplit.c - An OpenPGP packet splitting tool
 * Copyright (C) 2001 Free Software Foundation, Inc.
 *
 * This file is part of GnuPG.
 *
 * GnuPG is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * GnuPG is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 */

/* 
 * TODO: Add an option to uncompress packets.  This should come quite handy.
 */

#include <config.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <unistd.h>
#include <assert.h>
#ifdef HAVE_DOSISH_SYSTEM
  #include <fcntl.h> /* for setmode() */
#endif

#include "../g10/packet.h"
#include "util.h"

static int opt_verbose;
static const char *opt_prefix = "";

static void g10_exit( int rc );
static void split_packets (const char *fname);


enum cmd_and_opt_values { aNull = 0,
    oVerbose	  = 'v',
    oPrefix       = 'p',                          
aTest };


static ARGPARSE_OPTS opts[] = {

    { 301, NULL, 0, "@Options:\n " },

    { oVerbose, "verbose",   0, "verbose" },
    { oPrefix,  "prefix",    2, "|STRING|Prepend filenames with STRING" },
{0} };


const char *
strusage( int level )
{
    const char *p;
    switch( level ) {
      case 11: p = "gpgsplit (GnuPG)";
	break;
      case 13: p = VERSION; break;
      case 17: p = PRINTABLE_OS_NAME; break;
      case 19: p =
	    "Please report bugs to <bug-gnupg@gnu.org>.\n";
	break;
      case 1:
      case 40:	p =
	    "Usage: gpgsplit [options] [files] (-h for help)";
	break;
      case 41:	p =
	    "Syntax: gpgsplit [options] [files]\n"
	      "Split an OpenPGP message into packets\n";
	break;

      default:	p = default_strusage(level);
    }
    return p;
}



int
main( int argc, char **argv )
{
    ARGPARSE_ARGS pargs;

  #ifdef HAVE_DOSISH_SYSTEM
    setmode( fileno(stdin), O_BINARY );
    setmode( fileno(stdout), O_BINARY );
  #endif
    log_set_name("gpgsplit");

    pargs.argc = &argc;
    pargs.argv = &argv;
    pargs.flags=  1;  /* do not remove the args */
    while( optfile_parse( NULL, NULL, NULL, &pargs, opts) ) {
	switch( pargs.r_opt ) {
          case oVerbose: opt_verbose = 1; break;
          case oPrefix: opt_prefix = pargs.r.ret_str; break;
	  default : pargs.err = 2; break;
	}
    }

    if( log_get_errorcount(0) )
	g10_exit(2);

    if (!argc)
        split_packets (NULL);
    else {
        for ( ;argc; argc--, argv++) 
            split_packets (*argv);
    }

    g10_exit (0);
    return 0; 
}


static void
g10_exit( int rc )
{
    rc = rc? rc : log_get_errorcount(0)? 2 : 0;
    exit(rc );
}

static const char *
pkttype_to_string (int pkttype)
{
    const char *s;
    switch (pkttype) {
	case PKT_PUBKEY_ENC    : s = "pk_enc"; break;
	case PKT_SIGNATURE     : s = "sig"; break;
	case PKT_SYMKEY_ENC    : s = "sym_enc"; break;
	case PKT_ONEPASS_SIG   : s = "onepass_sig"; break;
	case PKT_SECRET_KEY    : s = "secret_key"; break;
	case PKT_PUBLIC_KEY    : s = "public_key"; break;
	case PKT_SECRET_SUBKEY : s = "secret_subkey"; break;
	case PKT_COMPRESSED    : s = "compressed"; break;
	case PKT_ENCRYPTED     : s = "encrypted"; break;
	case PKT_MARKER	       : s = "marker"; break;
	case PKT_PLAINTEXT     : s = "plaintext"; break;
	case PKT_RING_TRUST    : s = "ring_trust"; break;
	case PKT_USER_ID       : s = "user_id"; break;
	case PKT_PUBLIC_SUBKEY : s = "public_subkey"; break;
	case PKT_OLD_COMMENT   : s = "old_comment"; break;
	case PKT_PHOTO_ID      : s = "photo_id"; break;
	case PKT_ENCRYPTED_MDC : s = "encrypted_mdc"; break;
	case PKT_MDC 	       : s = "mdc"; break;
	case PKT_COMMENT       : s = "comment"; break;
        case PKT_GPG_CONTROL   : s = "gpg_control"; break;
      default: s = "unknown"; break;
    }
    return s;
}


/*
 * Create a new filename and a return a pointer to a statically
 * allocated buffer 
 */
static char *
create_filename (int pkttype)
{
    static unsigned int partno = 0;
    static char *name;

    if (!name) 
        name = m_alloc (strlen (opt_prefix) + 100 );

    assert (pkttype < 1000 && pkttype >= 0 );
    partno++;
    sprintf (name, "%s%06u-%03d.%.40s",
             opt_prefix, partno, pkttype, pkttype_to_string (pkttype));
    return name;
}

static int
read_u16 (FILE *fp, size_t *rn)
{
    int c;

    if ( (c = getc (fp)) == EOF )
        return -1;
    *rn = c << 8;
    if ( (c = getc (fp)) == EOF )
        return -1;
    *rn |= c;
    return 0;
}

static int
read_u32 (FILE *fp, unsigned long *rn)
{
    size_t tmp;

    if (read_u16 (fp, &tmp))
        return -1;
    *rn = tmp << 16;
    if (read_u16 (fp, &tmp))
        return -1;
    *rn |= tmp;
    return 0;
}


/* hdr must pint to a buffer large enough to hold all header bytes */
static int
write_part ( const char *fname, FILE *fpin, unsigned long pktlen,
             int pkttype, int partial, unsigned char *hdr, size_t hdrlen)
{
    FILE *fpout;
    int c, first;
    unsigned char *p;
    const char *outname = create_filename (pkttype);

    /* fixme: should we check that this file does not yet exist? */
    if (opt_verbose)
        log_info ("writing `%s'\n", outname);
    fpout = fopen (outname, "wb");
    if (!fpout) {
        log_error ("error creating `%s': %s\n", outname, strerror(errno));
        /* stop right now, otherwise we would mess up the sequence of
         * the part numbers */
        g10_exit (1);
    }

    for (p=hdr; hdrlen; p++, hdrlen--) {
        if ( putc (*p, fpout) == EOF )
            goto write_error;
    }
    
    first = 1;
    while (partial) {
        size_t partlen;

        if (partial == 1) { /* openpgp */
            if( first ) {
                c = pktlen;
                assert( c >= 224 && c < 255 );
		first = 0;
            }
            else if( (c = getc (fpin)) == EOF ) {
                goto read_error;
            }
            else
                hdr[hdrlen++] = c;
            
            if( c < 192 ) {
                pktlen = c;
                partial = 0; /* (last segment may follow) */
            }
            else if( c < 224 ) {
                pktlen = (c - 192) * 256;
                if( (c = getc (fpin)) == EOF ) 
                    goto read_error;
                hdr[hdrlen++] = c;
                pktlen += c + 192;
                partial = 0;
            }
            else if( c == 255 ) {
                if (read_u32 (fpin, &pktlen))
                    goto read_error;
                hdr[hdrlen++] = pktlen >> 24;
                hdr[hdrlen++] = pktlen >> 16;
                hdr[hdrlen++] = pktlen >> 8;
                hdr[hdrlen++] = pktlen;
                partial = 0;
            }
            else { /* next partial body length */
                for (p=hdr; hdrlen; p++, hdrlen--) {
                    if ( putc (*p, fpout) == EOF )
                        goto write_error;
                }
                partlen = 1 << (c & 0x1f);
                for (; partlen; partlen--) {
                    if ((c = getc (fpin)) == EOF) 
                        goto read_error;
                    if ( putc (c, fpout) == EOF )
                        goto write_error;
                }
            }
        }
        else if (partial == 2) { /* old gnupg */
            assert (!pktlen);
            if ( read_u16 (fpin, &partlen) )
                goto read_error;
            hdr[hdrlen++] = partlen >> 8;
            hdr[hdrlen++] = partlen;
            for (p=hdr; hdrlen; p++, hdrlen--) {
                if ( putc (*p, fpout) == EOF )
                    goto write_error;
            }
            if (!partlen)
                partial = 0; /* end of packet */
            for (; partlen; partlen--) {
                c = getc (fpin);
                if (c == EOF) 
                    goto read_error;
                if ( putc (c, fpout) == EOF )
                    goto write_error;
            }
        }
        else { /* compressed: read to end */
            pktlen = 0;
            partial = 0;
            while ( (c=getc (fpin)) != EOF ) {
                if ( putc (c, fpout) == EOF )
                    goto write_error;
            }
            if (!feof (fpin))
                goto read_error;
            
        }

    }

    for (p=hdr; hdrlen; p++, hdrlen--) {
        if ( putc (*p, fpout) == EOF )
            goto write_error;
    }
    /* standard packet or last segment of partial length encoded packet */
    for (; pktlen; pktlen--) {
        c = getc (fpin);
        if (c == EOF) 
            goto read_error;
        if ( putc (c, fpout) == EOF )
            goto write_error;
    }
    
        
    if ( fclose (fpout) )
        log_error ("error closing `%s': %s\n", outname, strerror (errno));
    return 0;

 write_error:    
    log_error ("error writing `%s': %s\n", outname, strerror (errno));
    fclose (fpout);
    return 2;
    
 read_error: {
        int save = errno;
        fclose (fpout);
        errno = save;
    }
    return -1;
}



static int
do_split (const char *fname, FILE *fp)
{
    int c, ctb, pkttype;
    unsigned long pktlen = 0;
    int partial = 0;
    unsigned char header[20];
    int header_idx = 0;

    ctb = getc (fp);
    if (ctb == EOF)
        return 3; /* ready */
    header[header_idx++] = ctb;

    if( !(ctb & 0x80) ) {
        log_error("invalid CTB %02x\n", ctb );
	return 1;
    }
    if ( (ctb & 0x40) ) { /* new CTB */
	pkttype =  (ctb & 0x3f);
	if( (c = getc (fp)) == EOF )
            return -1;
        header[header_idx++] = c;

	if( c < 192 )
	    pktlen = c;
	else if( c < 224 ) {
	    pktlen = (c - 192) * 256;
	    if( (c = getc (fp)) == EOF ) 
                return -1;
            header[header_idx++] = c;
	    pktlen += c + 192;
	}
	else if( c == 255 ) {
            if (read_u32 (fp, &pktlen))
                return -1;
            header[header_idx++] = pktlen >> 24;
            header[header_idx++] = pktlen >> 16;
            header[header_idx++] = pktlen >> 8;
            header[header_idx++] = pktlen; 
	}
	else { /* partial body length */
	    pktlen = c;
            partial = 1;
	}
    }
    else {
        int lenbytes;

	pkttype = (ctb>>2)&0xf;
	lenbytes = ((ctb&3)==3)? 0 : (1<<(ctb & 3));
	if( !lenbytes ) {
	    pktlen = 0; /* don't know the value */
	    if( pkttype == PKT_COMPRESSED )
                partial = 3;
            else
		partial = 2; /* the old GnuPG partial length encoding */
	}
	else {
	    for( ; lenbytes; lenbytes-- ) {
		pktlen <<= 8;
                if( (c = getc (fp)) == EOF ) 
                    return -1;
                header[header_idx++] = c;

		pktlen |= c;
	    }
	}
    }

    return write_part (fname, fp, pktlen, pkttype, partial,
                       header, header_idx);
}


static void
split_packets (const char *fname)
{
    FILE *fp;
    int rc;

    if (!fname || !strcmp (fname, "-")) {
        fp = stdin;
        fname = "-";
    }
    else if ( !(fp = fopen (fname,"rb")) ) {
        log_error ("can't open `%s': %s\n", fname, strerror (errno));
        return;
    }

    while ( !(rc = do_split (fname, fp)) )
        ;
    if ( rc > 0 )
        ; /* error already handled */
    else if ( ferror (fp) )
        log_error ("error reading `%s': %s\n", fname, strerror (errno));
    else
        log_error ("premature EOF while reading `%s'\n", fname );

    if ( fp != stdin )
        fclose (fp);
}