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+/* Lziprecover - Member recoverer program for lzip compressed files
+ Copyright (C) 2008, 2009 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 3 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/>.
+*/
+/*
+ Return values: 0 for a normal exit, 1 for environmental problems
+ (file not found, invalid flags, I/O errors, etc), 2 to indicate a
+ corrupt or invalid input file, 3 for an internal consistency error
+ (eg, bug) which caused lzip to panic.
+*/
+
+#define _FILE_OFFSET_BITS 64
+
+#include <cerrno>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <string>
+#include <vector>
+#include <fcntl.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <sys/stat.h>
+
+#include "arg_parser.h"
+#include "lzip.h"
+
+
+namespace {
+
+const char * invocation_name = 0;
+const char * const Program_name = "Lziprecover";
+const char * const program_name = "lziprecover";
+const char * const program_year = "2009";
+
+
+void show_help() throw()
+ {
+ std::printf( "%s - Member recoverer program for lzip compressed files.\n", Program_name );
+ std::printf( "\nUsage: %s [options] file\n", invocation_name );
+ std::printf( "Options:\n" );
+ std::printf( " -h, --help display this help and exit\n" );
+ std::printf( " -V, --version output version information and exit\n" );
+ std::printf( " -q, --quiet suppress all messages\n" );
+ std::printf( " -v, --verbose be verbose (a 2nd -v gives more)\n" );
+ std::printf( "\nReport bugs to lzip-bug@nongnu.org\n");
+ }
+
+
+void show_version() throw()
+ {
+ std::printf( "%s %s\n", Program_name, PROGVERSION );
+ std::printf( "Copyright (C) %s Antonio Diaz Diaz.\n", program_year );
+ std::printf( "License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>\n" );
+ std::printf( "This is free software: you are free to change and redistribute it.\n" );
+ std::printf( "There is NO WARRANTY, to the extent permitted by law.\n" );
+ }
+
+
+int open_instream( const std::string & input_filename ) throw()
+ {
+ int ides = open( input_filename.c_str(), O_RDONLY );
+ if( ides < 0 )
+ {
+ if( verbosity >= 0 )
+ std::fprintf( stderr, "%s: Can't open input file `%s': %s.\n",
+ program_name, input_filename.c_str(), std::strerror( errno ) );
+ }
+ else
+ {
+ struct stat in_stats;
+ const int i = fstat( ides, &in_stats );
+ if( i < 0 || !S_ISREG( in_stats.st_mode ) )
+ {
+ if( verbosity >= 0 )
+ std::fprintf( stderr, "%s: input file `%s' is not a regular file.\n",
+ program_name, input_filename.c_str() );
+ close( ides );
+ ides = -1;
+ }
+ }
+ return ides;
+ }
+
+
+int open_outstream( const std::string & output_filename ) throw()
+ {
+ int odes = open( output_filename.c_str(), O_CREAT | O_TRUNC | O_WRONLY, S_IRUSR | S_IWUSR );
+ if( odes < 0 )
+ {
+ if( verbosity >= 0 )
+ std::fprintf( stderr, "%s: Can't create output file `%s': %s.\n",
+ program_name, output_filename.c_str(), std::strerror( errno ) );
+ }
+ return odes;
+ }
+
+
+bool next_filename( std::string & output_filename )
+ {
+ for( int i = 7; i >= 3; --i ) // "rec00001"
+ {
+ if( output_filename[i] < '9' ) { ++output_filename[i]; return true; }
+ else output_filename[i] = '0';
+ }
+ return false;
+ }
+
+
+int search_header( const char * buffer, const int size, const int pos,
+ const long long last_header_pos,
+ const long long partial_file_pos )
+ {
+ for( int i = pos; i < size; ++i )
+ if( buffer[i] == magic_string[0] && buffer[i+1] == magic_string[1] &&
+ buffer[i+2] == magic_string[2] && buffer[i+3] == magic_string[3] )
+ {
+ File_trailer trailer;
+ for( unsigned int j = 0; j < sizeof trailer; ++j )
+ ((char *)&trailer)[j] = buffer[i-(sizeof trailer)+j];
+ if( partial_file_pos + i - trailer.member_size() == last_header_pos )
+ return i;
+ }
+ return -1;
+ }
+
+
+bool verify_header( const char * buffer, const int pos )
+ {
+ File_header header;
+ for( unsigned int i = 0; i < sizeof header; ++i )
+ ((char *)&header)[i] = buffer[pos+i];
+ if( !header.verify_magic() )
+ {
+ show_error( "bad magic number (file not created by lzip).\n" );
+ return false;
+ }
+ if( header.version == 0 )
+ {
+ show_error( "version 0 member format can't be recovered.\n" );
+ return false;
+ }
+ if( header.version != 1 )
+ {
+ if( verbosity >= 0 )
+ std::fprintf( stderr, "version %d member format not supported, newer %s needed.\n",
+ header.version, program_name );
+ return false;
+ }
+ return true;
+ }
+
+
+int process_file( const std::string & input_filename, char * & base_buffer )
+ {
+ const int hsize = sizeof( File_header );
+ const int tsize = sizeof( File_trailer );
+ const int buffer_size = 65536;
+ const int base_buffer_size = tsize + buffer_size + hsize;
+ base_buffer = new char[base_buffer_size];
+ char * const buffer = base_buffer + tsize;
+
+ const int inhandle = open_instream( input_filename );
+ if( inhandle < 0 ) return 1;
+ int size = readblock( inhandle, buffer, buffer_size + hsize ) - hsize;
+ bool at_stream_end = ( size < buffer_size );
+ if( size != buffer_size && errno )
+ { show_error( "read error", errno ); return 1; }
+ if( size <= tsize )
+ { show_error( "file too short" ); return 2; }
+ if( !verify_header( buffer, 0 ) ) return 2;
+
+ std::string output_filename( "rec00001" ); output_filename += input_filename;
+ int outhandle = open_outstream( output_filename );
+ if( outhandle < 0 ) { close( inhandle ); return 1; }
+
+ long long last_header_pos = 0;
+ long long partial_file_pos = 0;
+ int pos = 0;
+ while( size > 0 )
+ {
+ const int newpos = search_header( buffer, size - hsize, pos + hsize,
+ last_header_pos, partial_file_pos );
+ if( newpos > pos )
+ {
+ const int wr = writeblock( outhandle, buffer + pos, newpos - pos );
+ if( wr != newpos - pos )
+ { show_error( "write error", errno ); return 1; }
+ if( close( outhandle ) != 0 )
+ { show_error( "error closing output file", errno ); return 1; }
+ if( !next_filename( output_filename ) )
+ { show_error( "too many members in file" ); close( inhandle ); return 1; }
+ outhandle = open_outstream( output_filename );
+ if( outhandle < 0 ) { close( inhandle ); return 1; }
+ last_header_pos = partial_file_pos + newpos;
+ pos = newpos;
+ continue;
+ }
+ else
+ {
+ if( !at_stream_end )
+ {
+ partial_file_pos += buffer_size;
+ const int wr = writeblock( outhandle, buffer + pos, buffer_size - pos );
+ if( wr != buffer_size - pos )
+ { show_error( "write error", errno ); return 1; }
+ std::memcpy( base_buffer, base_buffer + buffer_size, tsize + hsize );
+ pos = 0;
+ }
+ else
+ {
+ const int wr = writeblock( outhandle, buffer + pos, size + hsize - pos );
+ if( wr != size + hsize - pos )
+ { show_error( "write error", errno ); return 1; }
+ break;
+ }
+ }
+ size = readblock( inhandle, buffer + hsize, buffer_size );
+ at_stream_end = ( size < buffer_size );
+ if( size != buffer_size && errno )
+ { show_error( "read error", errno ); return 1; }
+ }
+ close( inhandle );
+ if( close( outhandle ) != 0 )
+ { show_error( "error closing output file", errno ); return 1; }
+ return 0;
+ }
+
+} // end namespace
+
+
+int verbosity = 0;
+
+
+void show_error( const char * msg, const int errcode, const bool help ) throw()
+ {
+ if( verbosity >= 0 )
+ {
+ if( msg && msg[0] != 0 )
+ {
+ std::fprintf( stderr, "%s: %s", program_name, msg );
+ if( errcode > 0 ) std::fprintf( stderr, ": %s", std::strerror( errcode ) );
+ std::fprintf( stderr, "\n" );
+ }
+ if( help && invocation_name && invocation_name[0] != 0 )
+ std::fprintf( stderr, "Try `%s --help' for more information.\n", invocation_name );
+ }
+ }
+
+
+void internal_error( const char * msg )
+ {
+ std::string s( "internal error: " ); s += msg;
+ show_error( s.c_str() );
+ std::exit( 3 );
+ }
+
+
+// Returns the number of bytes really read.
+// If (returned value < size) and (errno == 0), means EOF was reached.
+//
+int readblock( const int fd, char * buf, const int size ) throw()
+ {
+ int rest = size;
+ errno = 0;
+ while( rest > 0 )
+ {
+ errno = 0;
+ const int n = read( fd, buf + size - rest, rest );
+ if( n > 0 ) rest -= n;
+ else if( n == 0 ) break;
+ else if( errno != EINTR && errno != EAGAIN ) break;
+ }
+ return ( rest > 0 ) ? size - rest : size;
+ }
+
+
+// Returns the number of bytes really written.
+// If (returned value < size), it is always an error.
+//
+int writeblock( const int fd, const char * buf, const int size ) throw()
+ {
+ int rest = size;
+ errno = 0;
+ while( rest > 0 )
+ {
+ errno = 0;
+ const int n = write( fd, buf + size - rest, rest );
+ if( n > 0 ) rest -= n;
+ else if( errno && errno != EINTR && errno != EAGAIN ) break;
+ }
+ return ( rest > 0 ) ? size - rest : size;
+ }
+
+
+int main( const int argc, const char * argv[] )
+ {
+ invocation_name = argv[0];
+
+ const Arg_parser::Option options[] =
+ {
+ { 'h', "help", Arg_parser::no },
+ { 'q', "quiet", Arg_parser::no },
+ { 'v', "verbose", Arg_parser::no },
+ { 'V', "version", Arg_parser::no },
+ { 0 , 0, Arg_parser::no } };
+
+ Arg_parser parser( argc, argv, options );
+ if( parser.error().size() ) // bad option
+ { show_error( parser.error().c_str(), 0, true ); return 1; }
+
+ int argind = 0;
+ for( ; argind < parser.arguments(); ++argind )
+ {
+ const int code = parser.code( argind );
+ if( !code ) break; // no more options
+ switch( code )
+ {
+ case 'h': show_help(); return 0;
+ case 'q': verbosity = -1; break;
+ case 'v': if( verbosity < 4 ) ++verbosity; break;
+ case 'V': show_version(); return 0;
+ default : internal_error( "uncaught option" );
+ }
+ }
+
+ if( argind + 1 != parser.arguments() )
+ { show_error( "you must specify exactly 1 file", 0, true ); return 1; }
+
+ char * base_buffer;
+ const int retval = process_file( parser.argument( argind ), base_buffer );
+
+ delete[] base_buffer;
+ return retval;
+ }