U-Boot Header Endianness

[GreaterGoodest]

I'm currently trying to write a loader to process a basic uboot image. The majority of the binary is little endian, but the image header itself is big endian. I'm able to handle this from the Ghidra UI, but I'm not sure of the best way to handle it in my loader.

Example:

public class uBootHeader extends StructureDataType {

    public uBootHeader(CategoryPath path, String name, int length) {
        super(path, name, 0);
        
        
        UnsignedIntegerDataType bigEndInteger = new UnsignedIntegerDataType();
        add(bigEndInteger, "ih_magic", "");
    }

}

In this struct, what would be the best way to flip the endianness of the integer I'm adding?

[ryanmkurtz]

ghidra/Ghidra/Features/Base/src/main/java/ghidra/app/util/bin/StructConverter.java

Lines 118 to 139 in 24f46bb

	/**
	* Recursively sets the given {@link Data} and its components to big/little endian
	*
	* @param data The {@link Data}
	* @param bigEndian True to set to big endian; false to set to little endian
	* @throws Exception if there was a problem setting the endianness
	*/
	public static void setEndian(Data data, boolean bigEndian) throws Exception {
	for (int i = 0; i < data.getNumComponents(); i++) {
	Data component = data.getComponent(i);
	SettingsDefinition[] settings = component.getDataType().getSettingsDefinitions();
	for (int j = 0; j < settings.length; j++) {
	if (settings[j] instanceof EndianSettingsDefinition endianSetting) {
	endianSetting.setBigEndian(component, bigEndian);
	}
	}
	for (int j = 0; j < component.getNumComponents(); j++) {
	setEndian(component.getComponent(j), bigEndian);
	}
	}
	}
	}

[GreaterGoodest]

Thanks. Implementation example below for anyone who stumbles on this later.

Listing listing = program.getListing();
Data headerData = null;
try {
    headerData = listing.createData(flatProgramApi.toAddr(0), uBootHeaderDT);
    StructConverter.setEndian(headerData, true);
} catch (CodeUnitInsertionException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
} catch (Exception e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}