Initial commit

Tupfile

@@ -0,0 +1 @@
+.gitignore

initrd_maker/Cargo.lock

@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "initrd_maker"
+version = "0.1.0"

initrd_maker/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "initrd_maker"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

initrd_maker/src/main.rs

@@ -0,0 +1,46 @@
+use std::{
+    env::args,
+    fs::File,
+    io::{self, Write},
+    path::Path,
+};
+
+const BLOCK_SIZE: u16 = 256;
+
+fn main() {
+    let mut archive = File::create("initrd").expect("Could not open initrd");
+    for file_path in args().skip(1) {
+        let file_path = Path::new(&file_path);
+        let file_name = file_path.file_name().unwrap();
+        let file_name_len =
+            u8::try_from(file_name.len()).expect("File name length greater than 256 bytes");
+        if file_name_len > 252 {
+            panic!("File {:?} has name longer than 252 bytes", file_name);
+        }
+        let mut file = File::open(file_path).expect("File did not exist");
+        let length = u16::try_from(file.metadata().expect("Could not get file metadata").len())
+            .expect("File size greater than 64 KiB");
+        let file_num_blocks = (length / BLOCK_SIZE) + if length % BLOCK_SIZE != 0 { 1 } else { 0 };
+        let mut header_block = Vec::new();
+        header_block.push(file_name_len);
+        header_block.extend_from_slice(file_name.to_str().unwrap().as_bytes());
+        header_block.push(0);
+        header_block.extend_from_slice(&length.to_le_bytes());
+        header_block.extend_from_slice(&file_num_blocks.to_le_bytes());
+        header_block.resize(BLOCK_SIZE as usize, 0);
+        archive
+            .write_all(&header_block)
+            .expect("Could not write to initrd");
+        let bytes_written =
+            io::copy(&mut file, &mut archive).expect("Could not read from file/write to initrd");
+        if (bytes_written as u16 % BLOCK_SIZE) != 0 {
+            let bytes_padding = (BLOCK_SIZE) - (bytes_written as u16 % BLOCK_SIZE);
+            for _ in 0..bytes_padding {
+                archive.write_all(&[0]).expect("Could not write to initrd");
+            }
+        }
+    }
+    archive
+        .write_all(&[0; 256])
+        .expect("Could not write to initrd");
+}