OpenEuphoria

Re: Modifying the Original EXE File

• Posted by Daniel Berstein <daber at PAIR.COM> Nov 23, 1998
• 510 views

>If I wanted to store some variable information IN THE EXE file (for
>instance, at the end of the exe I would put encoded info like user's
>name, etc.), would this be possible? If so, how so?


Yes, it can be done.

The steps are:

1.- Create a constant in your source that hold the size (in bytes) of
the bounded (.exe) file.

2.- To read/write data make a seek() to the above offset

3.- The very last statement in your source must be abort(0)

4.- Iterate step 1 until you match the exact size of the exe (using
bind and then dir)

Example:

constant ExeLength = 150000
....
function GetUserName()
    integer fn
    sequence exename,    -- Name of the executable
                      username    -- Data to be read

    exename = command_line()     -- Get command line
    exename = exename[2]             -- Get executable name

    fn = open(exename,"rb")            -- Open file for binary read

    seek(exename, ExeLength)       -- Let's get to the end of the EXE

    -- In this example we'll read 20 bytes that hold the user name
    for loop = 1 to 20 do
        username = username & getc(fn)
    end for

    close(fn)                  -- Close file

    return username    -- Return info
end function
....
abort(0)    -- The interpreter won't read after this

Regards,
    Daniel   Berstein
    daber at pair.com