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Diffstat (limited to 'lziprecover.cc')
| -rw-r--r-- | lziprecover.cc | 347 |
1 files changed, 347 insertions, 0 deletions
diff --git a/lziprecover.cc b/lziprecover.cc new file mode 100644 index 0000000..bca2744 --- /dev/null +++ b/lziprecover.cc @@ -0,0 +1,347 @@ +/* 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; + } |