summaryrefslogtreecommitdiffstats
path: root/delete_lz.cc
blob: 11c3a149cd049512a5628d9ab51c94c045ff3550 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
/*  Tarlz - Archiver with multimember lzip compression
    Copyright (C) 2013-2019 Antonio Diaz Diaz.

    This program 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.

    This program 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, see <http://www.gnu.org/licenses/>.
*/

#define _FILE_OFFSET_BITS 64

#include <cctype>
#include <cerrno>
#include <climits>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#include <vector>
#include <pthread.h>
#include <stdint.h>
#include <unistd.h>
#include <lzlib.h>

#include "arg_parser.h"
#include "lzip_index.h"
#include "tarlz.h"


/* Deleting from a corrupt archive must not worsen the corruption. Stop and
   tail-copy as soon as corruption is found. */
int delete_members_lz( const char * const archive_namep,
                       const Arg_parser & parser,
                       std::vector< char > & name_pending,
                       const Lzip_index & lzip_index,
                       const int filenames, const int infd, const int outfd,
                       const bool missing_crc, const bool permissive )
  {
  Resizable_buffer rbuf;
  LZ_Decoder * const decoder = LZ_decompress_open();
  if( !rbuf.size() || !decoder || LZ_decompress_errno( decoder ) != LZ_ok )
    { show_error( mem_msg ); return 1; }

  long long istream_pos = 0;		// source of next data move
  const long long cdata_size = lzip_index.cdata_size();
  int retval = 0;
  for( long i = 0; i < lzip_index.members(); ++i )
    {
    const long long mdata_pos = lzip_index.dblock( i ).pos();
    long long data_pos = mdata_pos;
    const long long mdata_end = lzip_index.dblock( i ).end();
    if( data_pos >= mdata_end ) continue;		// empty lzip member
    const long long member_pos = lzip_index.mblock( i ).pos();
    long long file_pos = member_pos;
    const long long member_end = lzip_index.mblock( i ).end();

    long long member_begin = 0;		// first pos of current tar member
    Extended extended;			// metadata from extended records
    bool prev_extended = false;		// prev header was extended
    LZ_decompress_reset( decoder );	// prepare for new member
    if( !safe_seek( infd, member_pos ) ) { retval = 1; break; }
    while( true )			// process one tar header per iteration
      {
      if( data_pos >= mdata_end )
        {
        if( data_pos == mdata_end && !prev_extended ) break;
        // member end exceeded or ends in extended
        show_file_error( archive_namep, "Member misalignment found." );
        retval = 2; goto done;
        }
      if( !prev_extended ) member_begin = data_pos;
      Tar_header header;
      const char * msg = 0;
      retval = archive_read_lz( decoder, infd, file_pos, member_end,
                                cdata_size, header, header_size, &msg );
      if( retval != 0 ) { show_file_error( archive_namep, msg ); goto done; }
      data_pos += header_size;
      if( !verify_ustar_chksum( header ) )
        {
        if( block_is_zero( header, header_size ) )		// EOF
          {
          if( prev_extended && !permissive )
            { show_file_error( archive_namep, fv_msg1 ); retval = 2; }
          goto done;
          }
        show_file_error( archive_namep, ( data_pos > header_size ) ?
                         bad_hdr_msg : posix_lz_msg );
        retval = 2;
        goto done;
        }

      const Typeflag typeflag = (Typeflag)header[typeflag_o];
      if( typeflag == tf_global )
        {
        if( prev_extended && !permissive )
          { show_file_error( archive_namep, fv_msg2 ); retval = 2; goto done; }
        Extended dummy;		// global headers are parsed and ignored
        retval = parse_records_lz( decoder, infd, file_pos, member_end,
                                   cdata_size, data_pos, dummy, header,
                                   rbuf, &msg, true );
        if( retval == 0 ) continue;
        show_file_error( archive_namep, msg ? msg : gblrec_msg );
        goto done;
        }
      if( typeflag == tf_extended )
        {
        if( prev_extended && !permissive ) { msg = fv_msg3; retval = 2; }
        else retval = parse_records_lz( decoder, infd, file_pos, member_end,
                                        cdata_size, data_pos, extended, header,
                                        rbuf, &msg, permissive );
        if( retval == 0 && !extended.crc_present() && missing_crc )
          { msg = mcrc_msg; retval = 2; }
        if( retval == 0 ) { prev_extended = true; continue; }
        show_file_error( archive_namep, msg ? msg : extrec_msg );
        goto done;
        }
      prev_extended = false;

      extended.fill_from_ustar( header );	// copy metadata from header

      long long rest = extended.file_size();
      const int rem = rest % header_size;
      if( rem ) rest += header_size - rem;		// padding
      if( data_pos + rest >= mdata_end ) data_pos += rest;
      else						// skip tar member
        if( ( retval = skip_member_lz( decoder, infd, file_pos, member_end,
                         cdata_size, data_pos, rest, &msg ) ) != 0 )
          goto done;

      if( !check_skip_filename( parser, name_pending, extended.path().c_str(),
                                filenames ) )		// delete tar member
        {
        // verify that members match
        if( member_begin != mdata_pos || data_pos != mdata_end )
          { show_file_error( extended.path().c_str(),
                             "Can't delete: not individually compressed." );
            retval = 2; extended.reset(); continue; }
        if( !show_member_name( extended, header, 1, rbuf ) )
          { retval = 1; goto done; }
        const long long size = member_pos - istream_pos;
        if( size > 0 )	// move pending data each time a member is deleted
          {
          if( istream_pos == 0 )
            { if( !safe_seek( outfd, size ) ) { retval = 1; break; } }
          else if( !safe_seek( infd, istream_pos ) ||
                   !copy_file( infd, outfd, size ) ) { retval = 1; break; }
          }
        istream_pos = member_end;
        }
      extended.reset();
      }
    }
done:
  if( LZ_decompress_close( decoder ) < 0 && !retval )
    { show_error( "LZ_decompress_close failed." ); retval = 1; }
  // tail copy keeps trailing data
  return tail_copy( archive_namep, parser, name_pending, lzip_index,
                    istream_pos, infd, outfd, retval );
  }