Does Your site has a login , if yes associate a directory to every login , say ddickman is logging in
attach him to ur base directory path "~/public/html/files/"
which will result in "~/public-html/files/ddickman"
then u can change to that paricular directory using
dir("~/public-html/files/ddickman")
php allows running command line commands thru system() function , just run a ls , take each and every file , and href to that particular file
Hope this works