There was some discussion of this on security.stackexchange.com recently
functions that can be used for arbitrary code execution
Well that reduces the scope a little - but since 'print' can be used to inject javascript (and therefore steal sessions etc) its still somewhat arbitrary.
isn't to list functions that should be blacklisted or otherwise disallowed. Rather, I'd like to have a grep-able list
That's a sensible approach.
Do consider writing your own parser though - very soon you're going to find a grep based approach getting out of control (awk would be a bit better). Pretty soon you're also going to start wishing you'd implemented a whitelist too!
In addition to the obvious ones, I'd recommend flagging up anything which does an include with an argument of anything other than a string literal. Watch out for __autoload() too.
