slackware-current/source/installer/sources/initrd/usr/lib/setup/INCISO

# Determine if there is an ISO image to loop-mount:
check_iso_image () {
 local IDIR=$1
 local MNTDIR=$2
 [ ! -d $IDIR ] && return 1
 [ -z "$MNTDIR" ] && MNTDIR=/var/log/mount

 IISO=$(ls --indicator-style=none "$IDIR"/slackwar*-install-dvd.iso 2>/dev/null |tail -1)

 if [ -n "$IISO" ]; then
  cat << EOF > $TMP/tempmsg

An ISO image of Slackware's install DVD was found.
Do you want me to mount the ISO image and use this as the package source?

EOF
  dialog --title "USE ISO IMAGE" --yesno "`cat $TMP/tempmsg`" 9 65
  RET=$?
  if [ ! $RET = 0 ]; then
   rm -f $TMP/tempmsg
   return 1
  fi

  rm -f $TMP/tempmsg
  umount -f $MNTDIR 2>/dev/null
  mkdir -p $MNTDIR
  mount -o loop,ro $IISO $MNTDIR
 else
  return 1
 fi
}