restructure build scripts

.cargo/config.toml

@@ -2,4 +2,4 @@
 target = "aarch64-unknown-none-softfloat"
 
 [target.aarch64-unknown-none-softfloat]
-runner = "./qemu-runner.sh"
+runner = "scripts/qemu-runner.sh"

.gitignore

@@ -1,3 +1,4 @@
 /target
+/build
 .gdb_history
 *.img

README.md

@@ -66,12 +66,10 @@ x86) before running on bare metal.
 ## Building and Running
 
 ### Prerequisites
-You will need QEMU for aarch64 emulation, dosfstools to create the virtual file system
-and gcc-aarch64-linux-gnu to compile bash for the image.
+You will need QEMU for aarch64 emulation and dosfstools to create the virtual file system.
 
 ```bash
-# Install QEMU (Ubuntu/Debian), dosfstools and gcc-aarch64-linux-gnu
-sudo apt install qemu-system-aarch64 dosfstools gcc-aarch64-linux-gnu
+sudo apt install qemu-system-aarch64 dosfstools
 ```
 
 Additionally you will need a version of the [aarch64-none-elf](https://developer.arm.com/Tools%20and%20Software/GNU%20Toolchain) toolchain installed.
@@ -87,6 +85,27 @@ Run the following command
 nix shell nixpkgs#pkgsCross.aarch64-embedded.stdenv.cc nixpkgs#pkgsCross.aarch64-embedded.stdenv.cc.bintools
 ```
 
+### Preparing the image
+
+First, run the following script to prepare the binaries for the image:
+```bash
+./scripts/build-deps.sh
+```
+
+This will download and build the necessary dependencies for the kernel and put them
+into the `build` directory.
+
+Once that is done, you can create the image using the following command:
+```bash
+sudo ./scripts/create-image.sh
+```
+
+This will create an image file named `moss.img` in the root directory of the project,
+format it as VFAT 32 and create the necessary files and directories for the kernel.
+
+This script needs to run with sudo to mount the image through a loop device,
+which is required to properly create the image for the kernel to work.
+
 ### Running via QEMU
 
 To build the kernel and launch it in QEMU:

mkrootfs-aarch64.sh

@@ -1,49 +0,0 @@
-#!/usr/bin/env bash
-set -euo pipefail
-
-IMG="test.img"
-MOUNT="/mnt/moss"
-
-if [ -f "$IMG" ]; then
-    echo "initrd file $IMG already exists.  Skipping."
-    exit 0
-fi
-
-dd if=/dev/zero of="$IMG" bs=1M count=128
-mkfs.vfat -F 32 "$IMG"
-
-if ! mountpoint -q "$MOUNT"; then
-    mount -o loop "$IMG" "$MOUNT"
-fi
-
-if [ ! -d /tmp/bash ]; then
-    git clone https://github.com/bminor/bash.git /tmp/bash
-fi
-
-
-pushd /tmp/bash
-if [ ! -f "/tmp/bash/bash" ]; then
-    ./configure --without-bash-malloc --enable-static-link --host=aarch64-linux-gnu CC=aarch64-linux-gnu-gcc
-    make
-fi
-
-if [ ! -f "$MOUNT/bin/bash" ]; then
-    sudo mkdir -p "$MOUNT/bin"
-    sudo cp bash "$MOUNT/bin"
-fi
-popd
-
-# busybox -- I couldn't get this to build.  I ended up restoring to a third-party static binary which isn't ideal but it get's things running.
-pushd "/tmp"
-if [ ! -f "$MOUNT/bin/busybox-aarch64-linux-gnu" ]; then
-    wget https://github.com/shutingrz/busybox-static-binaries-fat/raw/refs/heads/main/busybox-aarch64-linux-gnu
-    chmod +x busybox-aarch64-linux-gnu
-    sudo cp busybox-aarch64-linux-gnu "$MOUNT/bin"
-fi
-popd
-
-sudo mkdir -p "$MOUNT/dev"
-
-if mountpoint -q "$MOUNT"; then
-    umount "$MOUNT"
-fi

qemu-runner.sh

@@ -1,11 +0,0 @@
-#!/usr/bin/env bash
-set -e
-
-ELF="$1"
-BIN="${ELF%.elf}.bin"
-
-./mkrootfs-aarch64.sh
-
-# Convert to binary format
-aarch64-none-elf-objcopy -O binary "$ELF" "$BIN"
-qemu-system-aarch64 -M virt,gic-version=3 -initrd test.img -cpu cortex-a72 -m 2G -smp 4 -nographic -s -kernel "$BIN"

scripts/build-deps.sh

@@ -0,0 +1,49 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+base="$( cd "$( dirname "${BASH_SOURCE[0]}" )"/.. && pwd )"
+
+mkdir -p "$base/build/bin"
+rm -f "$base/build/bin"/*
+
+pushd "$base/build" &>/dev/null || exit 1
+
+if [ ! -f "aarch64-linux-musl-cross.tgz" ]
+then
+    wget https://musl.cc/aarch64-linux-musl-cross.tgz
+    tar -xzf aarch64-linux-musl-cross.tgz
+fi
+
+popd &>/dev/null || exit 1
+
+build=${build:-$(ls $base/scripts/deps)}
+
+export PATH="$base/build/aarch64-linux-musl-cross/bin:$PATH"
+
+for script in "$base/scripts/deps/"*
+do
+    [ -e "$script" ] || continue # skip if no file exists
+    [ -x "$script" ] || continue # skip if not executable
+
+    filename=$(basename "$script")
+
+    if [[ "$filename" == _* ]]
+    then
+        echo "Skipping: $filename"
+        continue
+    fi
+
+    # skip if not in build list
+    if ! grep -qw "$filename" <<< "$build";
+    then
+        echo "Skipping: $filename"
+        continue
+    fi
+
+    echo "Preparing: $filename"
+
+    # make sure each script is run in the base directory
+    pushd "$base" &>/dev/null || exit 1
+    bash "$script"
+    popd &>/dev/null || exit 1
+done

scripts/create-image.sh

@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+base="$( cd "$( dirname "${BASH_SOURCE[0]}" )"/.. && pwd )"
+pushd "$base" &>/dev/null || exit 1
+
+img="$base/moss.img"
+mount="$base/build/mount"
+
+mkdir -p "$mount"
+
+dd if=/dev/zero of="$img" bs=1M count=128
+mkfs.vfat -F 32 "$img"
+
+if ! mountpoint -q "$mount"; then
+    mount -o loop "$img" "$mount"
+fi
+
+mkdir -p "$mount/bin"
+mkdir -p "$mount/dev"
+
+cp "$base/build/bin"/* "$mount/bin"
+
+if mountpoint -q "$mount"; then
+    umount "$mount"
+fi
+popd &>/dev/null || exit 1

scripts/deps/README.md

@@ -0,0 +1,6 @@
+Every executable file in this directory is executed by `build-deps.sh`.
+
+When writing a new script you can assume you are in the root directory of the project.
+
+Downloads, git repos, etc. should be placed in the `build` directory.
+The built binaries should be placed in the `build/bin` directory.

scripts/deps/bash

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+bash_repo="${bash_repo:-https://git.savannah.gnu.org/git/bash.git}"
+bash_tag="${bash_tag:-bash-5.3}"
+stdlib="${stdlib:-musl}"
+
+pushd "build" &>/dev/null || exit 1
+
+if [ ! -d "bash" ]; then
+    git clone --depth 1 --branch "$bash_tag" "$bash_repo" "bash"
+else
+    pushd "bash" &>/dev/null || exit 1
+    git pull
+    popd &>/dev/null || exit 1
+fi
+
+pushd "bash" &>/dev/null || exit 1
+./configure --without-bash-malloc --enable-static-link --host="aarch64-linux-$stdlib" CC="aarch64-linux-$stdlib-gcc"
+make
+mv bash ../bin/bash
+popd &>/dev/null || exit 1
+
+popd &>/dev/null || exit 1

scripts/deps/busybox

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# busybox -- I couldn't get this to build.  I ended up restoring to a third-party static binary which isn't ideal but it get's things running.
+pushd "build" &>/dev/null || exit 1
+wget https://github.com/shutingrz/busybox-static-binaries-fat/raw/refs/heads/main/busybox-aarch64-linux-gnu
+chmod +x busybox-aarch64-linux-gnu
+mv busybox-aarch64-linux-gnu bin/busybox
+
+popd &>/dev/null || exit 1
+
+popd &>/dev/null || exit 1

scripts/qemu-runner.sh

@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+set -e
+
+base="$( cd "$( dirname "${BASH_SOURCE[0]}" )"/.. && pwd )"
+
+elf="$1"
+bin="${elf%.elf}.bin"
+
+# Convert to binary format
+aarch64-none-elf-objcopy -O binary "$elf" "$bin"
+qemu-system-aarch64 -M virt,gic-version=3 -initrd moss.img -cpu cortex-a72 -m 2G -smp 4 -nographic -s -kernel "$bin"

src/arch/arm64/boot/mod.rs

@@ -126,7 +126,7 @@ fn arch_init_stage2(frame: *mut ExceptionState) -> *mut ExceptionState {
     cpu_messenger_init(cpu_count());
 
     kmain(
-        "--init=/bin/sh --rootfs=fat32fs --automount=/dev,devfs".to_string(),
+        "--init=/bin/bash --rootfs=fat32fs --automount=/dev,devfs".to_string(),
         frame,
     );
 

src/main.rs

@@ -95,7 +95,7 @@ async fn launch_init(opts: KOptions) {
         let mount_point = VFS
             .resolve_path(path, VFS.root_inode())
             .await
-            .unwrap_or_else(|e| panic!("Could not find automount path: {e}"));
+            .unwrap_or_else(|e| panic!("Could not find automount path: {}. {e}", path.as_str()));
 
         VFS.mount(mount_point, fs, None)
             .await