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Diffstat (limited to '')
| -rw-r--r-- | lzip_index.c | 283 |
1 files changed, 283 insertions, 0 deletions
diff --git a/lzip_index.c b/lzip_index.c new file mode 100644 index 0000000..559fd7a --- /dev/null +++ b/lzip_index.c @@ -0,0 +1,283 @@ +/* Lunzip - Decompressor for the lzip format + Copyright (C) 2010-2022 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 <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#include "lzip.h" +#include "lzip_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 Lzip_index * const li, const char * const msg ) + { + const int len = strlen( msg ); + void * tmp = resize_buffer( li->error, li->error_size + len + 1 ); + if( !tmp ) return false; + li->error = (char *)tmp; + strncpy( li->error + li->error_size, msg, len + 1 ); + li->error_size += len; + return true; + } + + +static bool push_back_member( struct Lzip_index * const li, + 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( li->member_vector, + ( li->members + 1 ) * sizeof li->member_vector[0] ); + if( !tmp ) { add_error( li, mem_msg ); li->retval = 1; return false; } + li->member_vector = (struct Member *)tmp; + p = &(li->member_vector[li->members]); + init_member( p, dp, ds, mp, ms, dict_size ); + ++li->members; + return true; + } + + +static void Li_free_member_vector( struct Lzip_index * const li ) + { + if( li->member_vector ) + { free( li->member_vector ); li->member_vector = 0; } + li->members = 0; + } + + +static void Li_reverse_member_vector( struct Lzip_index * const li ) + { + struct Member tmp; + long i; + for( i = 0; i < li->members / 2; ++i ) + { + tmp = li->member_vector[i]; + li->member_vector[i] = li->member_vector[li->members-i-1]; + li->member_vector[li->members-i-1] = tmp; + } + } + + +static bool Li_check_header_error( struct Lzip_index * const li, + const Lzip_header header ) + { + if( !Lh_verify_magic( header ) ) + { add_error( li, bad_magic_msg ); li->retval = 2; return true; } + if( !Lh_verify_version( header ) ) + { add_error( li, bad_version( Lh_version( header ) ) ); li->retval = 2; + return true; } + if( !isvalid_ds( Lh_get_dictionary_size( header ) ) ) + { add_error( li, bad_dict_msg ); li->retval = 2; return true; } + return false; + } + +static void Li_set_errno_error( struct Lzip_index * const li, + const char * const msg ) + { + add_error( li, msg ); add_error( li, strerror( errno ) ); + li->retval = 1; + } + +static void Li_set_num_error( struct Lzip_index * const li, + const char * const msg, unsigned long long num ) + { + char buf[80]; + snprintf( buf, sizeof buf, "%s%llu", msg, num ); + add_error( li, buf ); + li->retval = 2; + } + + +static bool Li_read_header( struct Lzip_index * const li, const int fd, + Lzip_header header, const long long pos ) + { + if( seek_read( fd, header, Lh_size, pos ) != Lh_size ) + { Li_set_errno_error( li, "Error reading member header: " ); return false; } + return true; + } + + +/* If successful, push last member and set pos to member header. */ +static bool Li_skip_trailing_data( struct Lzip_index * const li, const int fd, + unsigned long long * const pos, + const bool ignore_trailing, + const bool loose_trailing ) + { + if( *pos < min_member_size ) return false; + enum { block_size = 16384, + buffer_size = block_size + Lt_size - 1 + Lh_size }; + uint8_t buffer[buffer_size]; + int bsize = *pos % block_size; /* total bytes in buffer */ + if( bsize <= buffer_size - block_size ) bsize += block_size; + int search_size = bsize; /* bytes to search for trailer */ + int rd_size = bsize; /* bytes to read from file */ + unsigned long long ipos = *pos - rd_size; /* aligned to block_size */ + + while( true ) + { + if( seek_read( fd, buffer, rd_size, ipos ) != rd_size ) + { Li_set_errno_error( li, "Error seeking member trailer: " ); return false; } + const uint8_t max_msb = ( ipos + search_size ) >> 56; + int i; + for( i = search_size; i >= Lt_size; --i ) + if( buffer[i-1] <= max_msb ) /* most significant byte of member_size */ + { + const Lzip_trailer * const trailer = + (const Lzip_trailer *)( buffer + i - Lt_size ); + const unsigned long long member_size = Lt_get_member_size( *trailer ); + if( member_size == 0 ) /* skip trailing zeros */ + { while( i > Lt_size && buffer[i-9] == 0 ) --i; continue; } + if( member_size > ipos + i || !Lt_verify_consistency( *trailer ) ) + continue; + Lzip_header header; + if( !Li_read_header( li, fd, header, ipos + i - member_size ) ) + return false; + if( !Lh_verify( header ) ) continue; + const Lzip_header * header2 = (const Lzip_header *)( buffer + i ); + const bool full_h2 = bsize - i >= Lh_size; + if( Lh_verify_prefix( *header2, bsize - i ) ) /* last member */ + { + if( !full_h2 ) add_error( li, "Last member in input file is truncated." ); + else if( !Li_check_header_error( li, *header2 ) ) + add_error( li, "Last member in input file is truncated or corrupt." ); + li->retval = 2; return false; + } + if( !loose_trailing && full_h2 && Lh_verify_corrupt( *header2 ) ) + { add_error( li, corrupt_mm_msg ); li->retval = 2; return false; } + if( !ignore_trailing ) + { add_error( li, trailing_msg ); li->retval = 2; return false; } + *pos = ipos + i - member_size; + const unsigned dictionary_size = Lh_get_dictionary_size( header ); + if( li->dictionary_size < dictionary_size ) + li->dictionary_size = dictionary_size; + return push_back_member( li, 0, Lt_get_data_size( *trailer ), *pos, + member_size, dictionary_size ); + } + if( ipos == 0 ) + { Li_set_num_error( li, "Bad trailer at pos ", *pos - Lt_size ); + return false; } + bsize = buffer_size; + search_size = bsize - Lh_size; + rd_size = block_size; + ipos -= rd_size; + memcpy( buffer + rd_size, buffer, buffer_size - rd_size ); + } + } + + +bool Li_init( struct Lzip_index * const li, const int infd, + const bool ignore_trailing, const bool loose_trailing ) + { + li->member_vector = 0; + li->error = 0; + li->insize = lseek( infd, 0, SEEK_END ); + li->members = 0; + li->error_size = 0; + li->retval = 0; + li->dictionary_size = 0; + if( li->insize < 0 ) + { Li_set_errno_error( li, "Input file is not seekable: " ); return false; } + if( li->insize < min_member_size ) + { add_error( li, "Input file is too short." ); li->retval = 2; + return false; } + if( li->insize > INT64_MAX ) + { add_error( li, "Input file is too long (2^63 bytes or more)." ); + li->retval = 2; return false; } + + Lzip_header header; + if( !Li_read_header( li, infd, header, 0 ) ) return false; + if( Li_check_header_error( li, header ) ) return false; + + unsigned long long pos = li->insize; /* always points to a header or to EOF */ + while( pos >= min_member_size ) + { + Lzip_trailer trailer; + if( seek_read( infd, trailer, Lt_size, pos - Lt_size ) != Lt_size ) + { Li_set_errno_error( li, "Error reading member trailer: " ); break; } + const unsigned long long member_size = Lt_get_member_size( trailer ); + if( member_size > pos || !Lt_verify_consistency( trailer ) ) + { /* bad trailer */ + if( li->members <= 0 ) + { if( Li_skip_trailing_data( li, infd, &pos, ignore_trailing, + loose_trailing ) ) continue; else return false; } + Li_set_num_error( li, "Bad trailer at pos ", pos - Lt_size ); + break; + } + if( !Li_read_header( li, infd, header, pos - member_size ) ) break; + if( !Lh_verify( header ) ) /* bad header */ + { + if( li->members <= 0 ) + { if( Li_skip_trailing_data( li, infd, &pos, ignore_trailing, + loose_trailing ) ) continue; else return false; } + Li_set_num_error( li, "Bad header at pos ", pos - member_size ); + break; + } + pos -= member_size; + const unsigned dictionary_size = Lh_get_dictionary_size( header ); + if( li->dictionary_size < dictionary_size ) + li->dictionary_size = dictionary_size; + if( !push_back_member( li, 0, Lt_get_data_size( trailer ), pos, + member_size, dictionary_size ) ) + return false; + } + if( pos != 0 || li->members <= 0 ) + { + Li_free_member_vector( li ); + if( li->retval == 0 ) + { add_error( li, "Can't create file index." ); li->retval = 2; } + return false; + } + Li_reverse_member_vector( li ); + long i; + for( i = 0; ; ++i ) + { + const long long end = block_end( li->member_vector[i].dblock ); + if( end < 0 || end > INT64_MAX ) + { + Li_free_member_vector( li ); + add_error( li, "Data in input file is too long (2^63 bytes or more)." ); + li->retval = 2; return false; + } + if( i + 1 >= li->members ) break; + li->member_vector[i+1].dblock.pos = end; + } + return true; + } + + +void Li_free( struct Lzip_index * const li ) + { + Li_free_member_vector( li ); + if( li->error ) { free( li->error ); li->error = 0; } + li->error_size = 0; + } |