Detecting a mime type fails in php

Question

I have the following PHP code that shows the mime type of an uploaded file.

Answer 1

I don't have a Unix box here to inspect a real "magic" file (the signatures database used to guess mime types) but a quick Google search revealed this:

# $File: fortran,v 1.6 2009/09/19 16:28:09 christos Exp $
# FORTRAN source
0       regex/100       \^[Cc][\ \t]    FORTRAN program
!:mime  text/x-fortran

Apparently, it scans the start of the file looking for lines that begin with a single C letter plus spaces, which seem to be a Fortran style comment. Thus the false positive:

somecolumn;
C F;