feat(userspace): shell runs programs (ls, cat) via spawn w/ terminal+storage+args page; ext4 holes read as zeros; storage re-attach same buffer

crates/apps/ls/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "ls"
+version = "0.1.0"
+edition = "2024"
+
+[[bin]]
+name = "ls"
+test = false
+bench = false
+
+[dependencies]
+types = { workspace = true }
+libkos = { workspace = true }

crates/apps/ls/src/main.rs

@@ -0,0 +1,35 @@
+//! Lists a directory: `ls [dir]`, the root by default.
+
+#![no_std]
+#![no_main]
+
+extern crate libkos;
+
+use libkos::fs::Storage;
+use libkos::println;
+
+/// Where storage's buffer is mapped.
+const STORAGE_BUF_VA: usize = 0x0180_0000;
+
+#[unsafe(no_mangle)]
+extern "C" fn main() {
+    let Some(mut fs) = libkos::start::storage().and_then(|ep| Storage::attach(ep, STORAGE_BUF_VA).ok()) else {
+        println!("ls: no storage");
+        return;
+    };
+    let dir = libkos::start::args().nth(1).unwrap_or("/");
+    let listed = fs.list_dir(dir.as_bytes(), |e| {
+        let name = core::str::from_utf8(e.name()).unwrap_or("?");
+        if name == "." || name == ".." {
+            return;
+        }
+        if e.is_dir {
+            println!("{}/", name);
+        } else {
+            println!("{:<24} {:>8}", name, e.size);
+        }
+    });
+    if listed.is_err() {
+        println!("ls: {}: no such directory", dir);
+    }
+}