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-rw-r--r--file_index.c268
1 files changed, 268 insertions, 0 deletions
diff --git a/file_index.c b/file_index.c
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+++ b/file_index.c
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+/* Lunzip - Decompressor for the lzip format
+ Copyright (C) 2010-2017 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 <errno.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "lzip.h"
+#include "file_index.h"
+
+
+static int seek_read( const int fd, uint8_t * const buf, const int size,
+ const long long pos )
+ {
+ if( lseek( fd, pos, SEEK_SET ) == pos )
+ return readblock( fd, buf, size );
+ return 0;
+ }
+
+
+static bool add_error( struct File_index * const fi, const char * const msg )
+ {
+ const int len = strlen( msg );
+ void * tmp = resize_buffer( fi->error, fi->error_size + len + 1 );
+ if( !tmp ) return false;
+ fi->error = (char *)tmp;
+ strncpy( fi->error + fi->error_size, msg, len + 1 );
+ fi->error_size += len;
+ return true;
+ }
+
+
+static bool push_back_member( struct File_index * const fi,
+ const long long dp, const long long ds,
+ const long long mp, const long long ms,
+ const unsigned dict_size )
+ {
+ struct Member * p;
+ void * tmp = resize_buffer( fi->member_vector,
+ ( fi->members + 1 ) * sizeof fi->member_vector[0] );
+ if( !tmp )
+ { add_error( fi, "Not enough memory." ); fi->retval = 1; return false; }
+ fi->member_vector = (struct Member *)tmp;
+ p = &(fi->member_vector[fi->members]);
+ init_member( p, dp, ds, mp, ms, dict_size );
+ ++fi->members;
+ return true;
+ }
+
+
+static void Fi_free_member_vector( struct File_index * const fi )
+ {
+ if( fi->member_vector )
+ { free( fi->member_vector ); fi->member_vector = 0; }
+ fi->members = 0;
+ }
+
+
+static void Fi_reverse_member_vector( struct File_index * const fi )
+ {
+ struct Member tmp;
+ long i;
+ for( i = 0; i < fi->members / 2; ++i )
+ {
+ tmp = fi->member_vector[i];
+ fi->member_vector[i] = fi->member_vector[fi->members-i-1];
+ fi->member_vector[fi->members-i-1] = tmp;
+ }
+ }
+
+
+static void Fi_set_errno_error( struct File_index * const fi,
+ const char * const msg )
+ {
+ add_error( fi, msg ); add_error( fi, strerror( errno ) );
+ fi->retval = 1;
+ }
+
+static void Fi_set_num_error( struct File_index * const fi,
+ const char * const msg, unsigned long long num )
+ {
+ char buf[80];
+ snprintf( buf, sizeof buf, "%s%llu", msg, num );
+ add_error( fi, buf );
+ fi->retval = 2;
+ }
+
+
+/* If successful, push last member and set pos to member header. */
+static bool Fi_skip_trailing_data( struct File_index * const fi,
+ const int fd, long long * const pos )
+ {
+ enum { block_size = 16384,
+ buffer_size = block_size + Ft_size - 1 + Fh_size };
+ uint8_t buffer[buffer_size];
+ int bsize = *pos % block_size; /* total bytes in buffer */
+ int search_size, rd_size;
+ unsigned long long ipos;
+ int i;
+ if( bsize <= buffer_size - block_size ) bsize += block_size;
+ search_size = bsize; /* bytes to search for trailer */
+ rd_size = bsize; /* bytes to read from file */
+ ipos = *pos - rd_size; /* aligned to block_size */
+ if( *pos < min_member_size ) return false;
+
+ while( true )
+ {
+ const uint8_t max_msb = ( ipos + search_size ) >> 56;
+ if( seek_read( fd, buffer, rd_size, ipos ) != rd_size )
+ { Fi_set_errno_error( fi, "Error seeking member trailer: " );
+ return false; }
+ for( i = search_size; i >= Ft_size; --i )
+ if( buffer[i-1] <= max_msb ) /* most significant byte of member_size */
+ {
+ File_header header;
+ File_trailer * trailer = (File_trailer *)( buffer + i - Ft_size );
+ const unsigned long long member_size = Ft_get_member_size( *trailer );
+ unsigned dictionary_size;
+ if( member_size == 0 )
+ { while( i > Ft_size && buffer[i-9] == 0 ) --i; continue; }
+ if( member_size < min_member_size || member_size > ipos + i )
+ continue;
+ if( seek_read( fd, header, Fh_size,
+ ipos + i - member_size ) != Fh_size )
+ { Fi_set_errno_error( fi, "Error reading member header: " );
+ return false; }
+ dictionary_size = Fh_get_dictionary_size( header );
+ if( !Fh_verify_magic( header ) || !Fh_verify_version( header ) ||
+ !isvalid_ds( dictionary_size ) ) continue;
+ if( Fh_verify_prefix( buffer + i, bsize - i ) )
+ {
+ add_error( fi, "Last member in input file is truncated or corrupt." );
+ fi->retval = 2; return false;
+ }
+ *pos = ipos + i - member_size;
+ return push_back_member( fi, 0, Ft_get_data_size( *trailer ), *pos,
+ member_size, dictionary_size );
+ }
+ if( ipos <= 0 )
+ { Fi_set_num_error( fi, "Member size in trailer is corrupt at pos ",
+ *pos - 8 );
+ return false; }
+ bsize = buffer_size;
+ search_size = bsize - Fh_size;
+ rd_size = block_size;
+ ipos -= rd_size;
+ memcpy( buffer + rd_size, buffer, buffer_size - rd_size );
+ }
+ }
+
+
+bool Fi_init( struct File_index * const fi, const int infd,
+ const bool ignore_trailing )
+ {
+ File_header header;
+ long long pos;
+ long i;
+ fi->member_vector = 0;
+ fi->error = 0;
+ fi->isize = lseek( infd, 0, SEEK_END );
+ fi->members = 0;
+ fi->error_size = 0;
+ fi->retval = 0;
+ if( fi->isize < 0 )
+ { Fi_set_errno_error( fi, "Input file is not seekable: " ); return false; }
+ if( fi->isize < min_member_size )
+ { add_error( fi, "Input file is too short." ); fi->retval = 2;
+ return false; }
+ if( fi->isize > INT64_MAX )
+ { add_error( fi, "Input file is too long (2^63 bytes or more)." );
+ fi->retval = 2; return false; }
+
+ if( seek_read( infd, header, Fh_size, 0 ) != Fh_size )
+ { Fi_set_errno_error( fi, "Error reading member header: " ); return false; }
+ if( !Fh_verify_magic( header ) )
+ { add_error( fi, bad_magic_msg ); fi->retval = 2; return false; }
+ if( !Fh_verify_version( header ) )
+ { add_error( fi, bad_version( Fh_version( header ) ) ); fi->retval = 2;
+ return false; }
+ if( !isvalid_ds( Fh_get_dictionary_size( header ) ) )
+ { add_error( fi, bad_dict_msg ); fi->retval = 2; return false; }
+
+ pos = fi->isize; /* always points to a header or to EOF */
+ while( pos >= min_member_size )
+ {
+ File_trailer trailer;
+ unsigned long long member_size;
+ unsigned dictionary_size;
+ if( seek_read( infd, trailer, Ft_size, pos - Ft_size ) != Ft_size )
+ { Fi_set_errno_error( fi, "Error reading member trailer: " ); break; }
+ member_size = Ft_get_member_size( trailer );
+ if( member_size < min_member_size || member_size > (unsigned long long)pos )
+ {
+ if( fi->members > 0 )
+ Fi_set_num_error( fi, "Member size in trailer is corrupt at pos ",
+ pos - 8 );
+ else if( Fi_skip_trailing_data( fi, infd, &pos ) )
+ { if( ignore_trailing ) continue;
+ add_error( fi, trailing_msg ); fi->retval = 2; return false; }
+ break;
+ }
+ if( seek_read( infd, header, Fh_size, pos - member_size ) != Fh_size )
+ { Fi_set_errno_error( fi, "Error reading member header: " ); break; }
+ dictionary_size = Fh_get_dictionary_size( header );
+ if( !Fh_verify_magic( header ) || !Fh_verify_version( header ) ||
+ !isvalid_ds( dictionary_size ) )
+ {
+ if( fi->members > 0 )
+ Fi_set_num_error( fi, "Bad header at pos ", pos - member_size );
+ else if( Fi_skip_trailing_data( fi, infd, &pos ) )
+ { if( ignore_trailing ) continue;
+ add_error( fi, trailing_msg ); fi->retval = 2; return false; }
+ break;
+ }
+ pos -= member_size;
+ if( !push_back_member( fi, 0, Ft_get_data_size( trailer ), pos,
+ member_size, dictionary_size ) )
+ return false;
+ }
+ if( pos != 0 || fi->members <= 0 )
+ {
+ Fi_free_member_vector( fi );
+ if( fi->retval == 0 )
+ { add_error( fi, "Can't create file index." ); fi->retval = 2; }
+ return false;
+ }
+ Fi_reverse_member_vector( fi );
+ for( i = 0; i < fi->members - 1; ++i )
+ {
+ const long long end = block_end( fi->member_vector[i].dblock );
+ if( end < 0 || end > INT64_MAX )
+ {
+ Fi_free_member_vector( fi );
+ add_error( fi, "Data in input file is too long (2^63 bytes or more)." );
+ fi->retval = 2; return false;
+ }
+ fi->member_vector[i+1].dblock.pos = end;
+ }
+ return true;
+ }
+
+
+void Fi_free( struct File_index * const fi )
+ {
+ Fi_free_member_vector( fi );
+ if( fi->error ) { free( fi->error ); fi->error = 0; }
+ fi->error_size = 0;
+ }