zlib minizip unpacked executables are corrupted - c++

Question

I'm trying to use miniunzip to extract some files. It works on Linux. On Windows, it throws no errors, but if the file is executable, the resulting binary doesn't work. I get a message window with a message about incompatibility with 64-bit Windows. If I use another utility, such as 7-zip, to unpack it, everything works fine, so the problem is here in my code. Here is the class method that does all the work.
bool FileHandler::unzip( string inputFile, string outputDirectory )
{
if (!fileExists(inputFile)) {
this->errorMessage = "Can't find file at " + inputFile;
return false;
}
unzFile zipFile = unzOpen(inputFile.c_str());
if( zipFile == nullptr ){
this->errorMessage = "FileHandler::unzip failed to open input file";
return false;
}
vector<string> files;
vector<string> folders;
unz_global_info globalInfo;
int err = unzGetGlobalInfo( zipFile, &globalInfo );
if (unzGoToFirstFile(zipFile) != UNZ_OK) {
this->errorMessage = "FileHandler::unzip failed calling unzGoToFirstFile";
return false;
}
for ( unsigned long i=0; i < globalInfo.number_entry && err == UNZ_OK; i++ ){
char filename[FILENAME_MAX];
unz_file_info subFileInfo;
err = unzGetCurrentFileInfo( zipFile, &subFileInfo, filename,
sizeof(filename), NULL, 0, NULL, 0);
if ( err == UNZ_OK )
{
char nLast = filename[subFileInfo.size_filename-1];
if ( nLast =='/' || nLast == '\\' )
{
folders.push_back(filename);
}
else
{
files.push_back(filename);
}
err = unzGoToNextFile(zipFile);
}
}
for ( string & folder : folders ){
string strippedFolder = folder.substr(0, folder.length()-1);
string dirPath = normalizePath(outputDirectory+"/"+strippedFolder);
if( ! makeDirectory( dirPath ) ){
this->errorMessage = "FileHandler::unzip Failed to create directory "+dirPath;
return false;
}
}
for ( auto it = files.begin(); it != files.end(); it++ ){
if( zipFile == 0 ){
this->errorMessage = "FileHandler::unzip invalid unzFile object at position 1";
return false;
}
string filename = *it;
//string filepath = outputDirectory + "/" + *it;
string filepath = normalizePath( outputDirectory + "/" + *it );
const char * cFile = filename.c_str();
const char * cPath = filepath.c_str();
int err = unzLocateFile( zipFile, cFile, 0 );
if ( err != UNZ_OK ){
this->errorMessage = "FileHandler::unzip error locating sub-file.";
return false;
}
err = unzOpenCurrentFile( zipFile );
if( err != UNZ_OK ){
this->errorMessage = "FileHandler::unzip error opening current file";
return false;
}
ofstream fileStream{ cPath };
// Need an ostream object here.
if( fileStream.fail() ){
this->errorMessage = "FileHandler::unzip error opening file stream at "+string(cPath);
return false;
}
unz_file_info curFileInfo;
err = unzGetCurrentFileInfo( zipFile, &curFileInfo, 0, 0, 0, 0, 0, 0);
if ( err != UNZ_OK )
{
this->errorMessage = "FileHandler::unzip failed to read size of file";
return false;
}
unsigned int size = (unsigned int)curFileInfo.uncompressed_size;
char * buf = new char[size];
size = unzReadCurrentFile( zipFile, buf, size );
if ( size < 0 ){
this->errorMessage = "FileHandler::unzip unzReadCurrentFile returned an error. ";
return false;
}
fileStream.write( buf, size );
fileStream.flush();
delete [] buf;
fileStream.close();
#ifndef _WIN32
vector<string> parts = splitString(filename, ".");
if( parts.size() == 1 ){ // In linux, assume file without extension is executable
mode_t old_mask = umask( 000 );
chmod( cPath, S_IRWXU|S_IRWXG|S_IROTH|S_IXOTH );
umask( old_mask );
}
#endif
unzCloseCurrentFile( zipFile );
}
unzClose(zipFile);
return true;
}

Answer 1

std::ostream opens files in text mode by default, you need to make it use binary mode instead.
On Linux there doesn't seem to be any difference between text and binary modes. But on Windows, attempting to write \n into a text file produces \r\n, currupting your data.
You need to change this line
ofstream fileStream{ cPath };
to
ofstream fileStream{ cPath, ostream::out | ostream::binary };