From 09661ec9e007be9c8eae88e45af7b2124ea9cfe1 Mon Sep 17 00:00:00 2001
From: Valentin Haudiquet <valentin.haudiquet@canonical.com>
Date: Wed, 17 Jun 2026 16:35:28 +0200
Subject: [PATCH] feat: use uncompressed initramfs

---
 src/qemu_vm.rs | 46 ++++++++++------------------------------------
 1 file changed, 10 insertions(+), 36 deletions(-)

diff --git a/src/qemu_vm.rs b/src/qemu_vm.rs
index 07152de..8998926 100644
--- a/src/qemu_vm.rs
+++ b/src/qemu_vm.rs
@@ -160,56 +160,30 @@ fn get_arch_package_suffix(arch: &str) -> &str {
     }
 }
 
-/// Create a gzipped cpio initramfs from a directory
+/// Create an uncompressed cpio initramfs from a directory
 fn create_initramfs(rootfs: &PathBuf) -> Result<PathBuf> {
-    // Create a temporary file for the initramfs
-    let initramfs_path = rootfs.parent().unwrap().join("initramfs.cpio.gz");
+    // Create a temporary file for the initramfs (uncompressed cpio)
+    let initramfs_path = rootfs.parent().unwrap().join("initramfs.cpio");
 
     // Create progress bar
     let pb = ProgressBar::new_spinner();
     pb.set_style(ProgressStyle::default_spinner()
         .template("{spinner:.green} {msg} ({pos} files)")
         .unwrap());
-    pb.set_message("Scanning rootfs...");
+    pb.set_message("Creating initramfs...");
 
     // Create the cpio archive with progress
     let cpio_data = create_cpio_archive(rootfs, &pb)?;
     let total_bytes = cpio_data.len() as u64;
     let file_count = pb.position();
 
-    // Finish the scanning progress bar
+    // Write directly to file (no compression)
+    std::fs::write(&initramfs_path, &cpio_data)
+        .context("Failed to write initramfs file")?;
+
+    // Finish progress bar
     pb.finish_and_clear();
-
-    // Create progress bar for compression
-    let compress_pb = ProgressBar::new(total_bytes);
-    compress_pb.set_style(ProgressStyle::default_bar()
-        .template("{spinner:.green} Compressing initramfs... {bytes}/{total_bytes} ({eta})")
-        .unwrap()
-        .progress_chars("##-"));
-
-    // Compress with gzip, writing in chunks to update progress
-    let mut output_file = std::fs::File::create(&initramfs_path)
-        .context("Failed to create initramfs file")?;
-    
-    let mut encoder = flate2::write::GzEncoder::new(&mut output_file, flate2::Compression::fast());
-    
-    // Write in 64KB chunks to provide progress updates
-    const CHUNK_SIZE: usize = 64 * 1024;
-    let mut offset = 0;
-    while offset < cpio_data.len() {
-        let end = std::cmp::min(offset + CHUNK_SIZE, cpio_data.len());
-        encoder.write_all(&cpio_data[offset..end])
-            .context("Failed to write compressed initramfs")?;
-        offset = end;
-        compress_pb.set_position(offset as u64);
-    }
-    encoder.finish()
-        .context("Failed to finalize gzip compression")?;
-
-    // Clear progress bar and print message only in verbose mode
-    compress_pb.finish_and_clear();
-    veprintln!("Initramfs created: {} bytes -> {} bytes compressed, {} files",
-               total_bytes, output_file.metadata().ok().map(|m| m.len()).unwrap_or(0), file_count);
+    veprintln!("Initramfs created: {} bytes, {} files", total_bytes, file_count);
 
     Ok(initramfs_path)
 }