g10/textfilter.c

   1 /* textfilter.c
   2  * Copyright (C) 1998, 1999, 2000, 2001 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 2 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, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  19  */
  20
  21 #include <config.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <errno.h>
  26 #include <assert.h>
  27
  28 #include "gpg.h"
  29 #include "errors.h"
  30 #include "iobuf.h"
  31 #include "memory.h"
  32 #include "util.h"
  33 #include "filter.h"
  34 #include "i18n.h"
  35 #include "options.h"
  36
  37 #ifdef HAVE_DOSISH_SYSTEM
  38 #define LF "\r\n"
  39 #else
  40 #define LF "\n"
  41 #endif
  42
  43 #define MAX_LINELEN 19995 /* a little bit smaller than in armor.c */
  44                           /* to make sure that a warning is displayed while */
  45                           /* creating a message */
  46
  47 static unsigned
  48 len_without_trailing_chars( byte *line, unsigned len, const char *trimchars )
  49 {
  50     byte *p, *mark;
  51     unsigned n;
  52
  53     for(mark=NULL, p=line, n=0; n < len; n++, p++ ) {
  54         if( strchr( trimchars, *p ) ) {
  55             if( !mark )
  56                 mark = p;
  57         }
  58         else
  59             mark = NULL;
  60     }
  61
  62     return mark? (mark - line) : len;
  63 }
  64
  65 unsigned
  66 len_without_trailing_ws( byte *line, unsigned len )
  67 {
  68     return len_without_trailing_chars( line, len, " \t\r\n" );
  69 }
  70
  71
  72
  73
  74 static int
  75 standard( text_filter_context_t *tfx, iobuf_t a,
  76           byte *buf, size_t size, size_t *ret_len)
  77 {
  78     int rc=0;
  79     size_t len = 0;
  80     unsigned maxlen;
  81
  82     assert( size > 10 );
  83     size -= 2;  /* reserve 2 bytes to append CR,LF */
  84     while( !rc && len < size ) {
  85         int lf_seen;
  86
  87         while( len < size && tfx->buffer_pos < tfx->buffer_len )
  88             buf[len++] = tfx->buffer[tfx->buffer_pos++];
  89         if( len >= size )
  90             continue;
  91
  92         /* read the next line */
  93         maxlen = MAX_LINELEN;
  94         tfx->buffer_pos = 0;
  95         tfx->buffer_len = iobuf_read_line( a, &tfx->buffer,
  96                                            &tfx->buffer_size, &maxlen );
  97         if( !maxlen )
  98             tfx->truncated++;
  99         if( !tfx->buffer_len ) {
 100             if( !len )
 101                 rc = -1; /* eof */
 102             break;
 103         }
 104         lf_seen = tfx->buffer[tfx->buffer_len-1] == '\n';
 105         tfx->buffer_len = trim_trailing_ws( tfx->buffer, tfx->buffer_len );
 106         if( lf_seen ) {
 107             tfx->buffer[tfx->buffer_len++] = '\r';
 108             tfx->buffer[tfx->buffer_len++] = '\n';
 109         }
 110     }
 111     *ret_len = len;
 112     return rc;
 113 }
 114
 115
 116
 117
 118 /****************
 119  * The filter is used to make canonical text: Lines are terminated by
 120  * CR, LF, trailing white spaces are removed.
 121  */
 122 int
 123 text_filter( void *opaque, int control,
 124              iobuf_t a, byte *buf, size_t *ret_len)
 125 {
 126     size_t size = *ret_len;
 127     text_filter_context_t *tfx = opaque;
 128     int rc=0;
 129
 130     if( control == IOBUFCTRL_UNDERFLOW ) {
 131         rc = standard( tfx, a, buf, size, ret_len );
 132     }
 133     else if( control == IOBUFCTRL_FREE ) {
 134         if( tfx->truncated )
 135             log_error(_("can't handle text lines longer than %d characters\n"),
 136                         MAX_LINELEN );
 137         xfree ( tfx->buffer );
 138         tfx->buffer = NULL;
 139     }
 140     else if( control == IOBUFCTRL_DESC )
 141         *(char**)buf = "text_filter";
 142     return rc;
 143 }
 144
 145
 146 /****************
 147  * Copy data from INP to OUT and do some escaping if requested.
 148  * md is updated as required by rfc2440
 149  */
 150 int
 151 copy_clearsig_text( iobuf_t out, iobuf_t inp, MD_HANDLE md,
 152                     int escape_dash, int escape_from, int pgp2mode )
 153 {
 154     unsigned maxlen;
 155     byte *buffer = NULL;    /* malloced buffer */
 156     unsigned bufsize;       /* and size of this buffer */
 157     unsigned n;
 158     int truncated = 0;
 159     int pending_lf = 0;
 160
 161     if( !opt.pgp2_workarounds )
 162         pgp2mode = 0;
 163
 164     if( !escape_dash )
 165         escape_from = 0;
 166
 167     for(;;) {
 168         maxlen = MAX_LINELEN;
 169         n = iobuf_read_line( inp, &buffer, &bufsize, &maxlen );
 170         if( !maxlen )
 171             truncated++;
 172
 173         if( !n )
 174             break; /* read_line has returned eof */
 175
 176         /* update the message digest */
 177         if( escape_dash ) {
 178             if( pending_lf ) {
 179                 gcry_md_putc( md, '\r' );
 180                 gcry_md_putc( md, '\n' );
 181             }
 182             gcry_md_write( md, buffer,
 183                      len_without_trailing_chars( buffer, n,
 184                                                  pgp2mode? " \r\n":" \t\r\n"));
 185         }
 186         else
 187             gcry_md_write( md, buffer, n );
 188         pending_lf = buffer[n-1] == '\n';
 189
 190         /* write the output */
 191         if(    ( escape_dash && *buffer == '-')
 192             || ( escape_from && n > 4 && !memcmp(buffer, "From ", 5 ) ) ) {
 193             iobuf_put( out, '-' );
 194             iobuf_put( out, ' ' );
 195         }
 196
 197 #if  0 /*defined(HAVE_DOSISH_SYSTEM)*/
 198         /* We don't use this anymore because my interpretation of rfc2440 7.1
 199          * is that there is no conversion needed.  If one decides to
 200          * clearsign a unix file on a DOS box he will get a mixed line endings.
 201          * If at some point it turns out, that a conversion is a nice feature
 202          * we can make an option out of it.
 203          */
 204         /* make sure the lines do end in CR,LF */
 205         if( n > 1 && ( (buffer[n-2] == '\r' && buffer[n-1] == '\n' )
 206                             || (buffer[n-2] == '\n' && buffer[n-1] == '\r'))) {
 207             iobuf_write( out, buffer, n-2 );
 208             iobuf_put( out, '\r');
 209             iobuf_put( out, '\n');
 210         }
 211         else if( n && buffer[n-1] == '\n' ) {
 212             iobuf_write( out, buffer, n-1 );
 213             iobuf_put( out, '\r');
 214             iobuf_put( out, '\n');
 215         }
 216         else
 217             iobuf_write( out, buffer, n );
 218
 219 #else
 220         iobuf_write( out, buffer, n );
 221 #endif
 222     }
 223
 224     /* at eof */
 225     if( !pending_lf ) { /* make sure that the file ends with a LF */
 226         iobuf_writestr( out, LF );
 227         if( !escape_dash )
 228             gcry_md_putc( md, '\n' );
 229     }
 230
 231     if( truncated )
 232         log_info(_("input line longer than %d characters\n"), MAX_LINELEN );
 233
 234     return 0; /* okay */
 235 }