Vendor dependencies

Let's see how I like this workflow.

vendor/procfs/examples/lsmod.rs

@@ -0,0 +1,30 @@
+use std::collections::HashMap;
+
+fn print(name: &str, indent: usize, mods: &HashMap<&str, Vec<&str>>) {
+    println!("{}{} {}", if indent == 0 { "-" } else { " " }, " ".repeat(indent), name);
+
+    if let Some(uses_list) = mods.get(name) {
+        for name in uses_list {
+            print(name, indent + 2, mods);
+        }
+    }
+}
+
+fn main() {
+    let modules = procfs::modules().unwrap();
+
+    // each module has a list of what other modules use it.  Let's invert this and create a list of the modules used by each module.
+    // This maps a module name to a list of modules that it uses
+    let mut map: HashMap<&str, Vec<&str>> = HashMap::new();
+
+    for module in modules.values() {
+        for name in &module.used_by {
+            map.entry(name).or_default().push(&module.name);
+        }
+    }
+
+    // println!("{:?}", map["xt_policy"]);
+    for modname in map.keys() {
+        print(modname, 0, &map);
+    }
+}