Finding the realpath of a file in unix

I have the following code, which is expected to do the following,

Directory name (dirName) and a prefix is provided as input to the function.
Lists out all the contents one level down from the provided input directory (dirName) and starts populating the file details within the sub directories using the os.walk function.
Once the files are found they are checked against a specific prefix and processed further.

The motive is that once a file is identified (which satisfies a prefix), I want the absolute realpath of that file. I tried using the Path(libfile).resolve() option but its giving only the present working directory from where the script is run as against the realpath of that file. Could you explain where I am going wrong?

import os
from pathlib import Path

def directory(dirName, prefix):

process_dir = [name for name in os.listdir(dirName) if os.path.isdir(os.path.join(dirName, name))]
for entry in process_dir:
    for dirname, directory, files in os.walk(os.path.join(dirName, entry)):
        for libfile in files:
            if libfile.startswith((prefix)):
                return(Path(libfile).resolve())

Python version 3.6.2.

Solution

Change this line:

return(Path(libfile).resolve())

To this:

return (Path(dirname) / libfile).resolve()

I agree with the comment from dawg that using a recursive glob pattern would be a better choice here.