#!/usr/bin/env python3

"""
display the kernel module dependencies

author: Michael Hohn <mhhohn@lbl.gov>
 based on: modgraph.tcl by John Ellson <ellson@research.att.com>
"""

import gv

with open("/proc/modules", "rt", encoding="utf-8") as mod:
    modules = mod.readlines()

G = gv.digraph("G")
N = gv.protonode(G)
E = gv.protoedge(G)

gv.setv(G, "rankdir", "LR")
gv.setv(G, "nodesep", "0.05")
gv.setv(N, "shape", "box")
gv.setv(N, "width", "0")
gv.setv(N, "height", "0")
gv.setv(N, "margin", ".03")
gv.setv(N, "fontsize", "8")
gv.setv(N, "fontname", "helvetica")
gv.setv(E, "arrowsize", ".4")

for rec in modules:
    fields = rec.split(" ")
    n = gv.node(G, fields[0])
    for usedby in fields[3].split(","):
        if usedby not in ("-", ""):
            gv.edge(n, gv.node(G, usedby))

gv.layout(G, "dot")
gv.render(G, "xlib")