name: Uring Kernel Version Test

on:
  workflow_call:
    inputs:
      kernel_version:
        description: 'Version of the Linux kernel to build'
        required: true
        type: string

jobs:
  build:
    runs-on: ubuntu-latest
    env:
      KERNEL_VERSION: ${{ inputs.kernel_version }}
    steps:
      - uses: actions/checkout@v5

      - name: Install system dependencies
        run: |
          sudo apt-get update
          sudo apt-get install -y \
            build-essential bison flex libssl-dev libelf-dev \
            qemu-system-x86 busybox-static cpio xz-utils wget

      - name: Cache Linux source
        id: cache-kernel
        uses: actions/cache@v4
        with:
          path: linux-${{ env.KERNEL_VERSION }}
          key: kernel-${{ env.KERNEL_VERSION }}

      - name: Download & build Linux kernel
        if: steps.cache-kernel.outputs.cache-hit != 'true'
        run: |
          MAJOR=${KERNEL_VERSION%%.*}
          wget https://cdn.kernel.org/pub/linux/kernel/v${MAJOR}.x/linux-${KERNEL_VERSION}.tar.xz
          tar xf linux-${KERNEL_VERSION}.tar.xz
          cd linux-${KERNEL_VERSION}
          make defconfig
          make -j$(nproc)

      - name: Generate test binaries with io_uring enabled
        run: |
          # Build both integration (tokio/tests/) and unit (e.g., tokio/src/fs/file/tests.rs) tests with io_uring enabled
          rustup target add x86_64-unknown-linux-musl
          RUSTFLAGS="--cfg tokio_unstable" \
            cargo test -p tokio --features full,io-uring \
            --target x86_64-unknown-linux-musl --test 'fs*' --lib --no-run

      - name: Prepare initramfs + tests binaries
        run: |
          set -e
          rm -rf initramfs
          mkdir -p initramfs/{bin,bin/tests,sbin,proc,sys,tmp}

          # Copy test binaries into initramfs
          for bin in target/x86_64-unknown-linux-musl/debug/deps/{fs_*,tokio-*}; do
            if [ -f "$bin" ] && [ -x "$bin" ]; then
              cp "$bin" initramfs/bin/tests
            fi
          done

          # Add BusyBox & symlinks
          cp /usr/bin/busybox initramfs/bin/
          for cmd in sh mount uname true sleep; do ln -sf busybox initramfs/bin/$cmd; done
          ln -sf ../bin/busybox initramfs/sbin/poweroff

          # Generate init script
          cat > initramfs/init << 'EOF'
          #!/bin/sh
          set -e
          mkdir -p /dev
          # create device nodes, as some tests require them
          mknod /dev/null c 1 3
          mknod /dev/zero c 1 5
          mknod /dev/tty c 5 0
          mount -t proc proc /proc
          mount -t sysfs sysfs /sys
          mkdir -p /tmp && mount -t tmpfs -o mode=1777 tmpfs /tmp
          for f in /bin/tests/*; do RUST_BACKTRACE=1 "$f" ; done
          EOF
          chmod +x initramfs/init

          # Pack into a CPIO archive
          (cd initramfs && find . -print0 \
            | cpio --null -ov --format=newc | gzip -9 > ../initramfs.cpio.gz)

      - name: Run tests in QEMU
        run: |
          qemu-system-x86_64 \
            -kernel linux-${{ env.KERNEL_VERSION }}/arch/x86/boot/bzImage \
            -initrd initramfs.cpio.gz \
            -append "console=ttyS0 rootfstype=ramfs panic=1" \
            -nographic -no-reboot -m 1024 -action panic=exit-failure 2>&1 | tee qemu-output.log

          # qemu always exits with 0, so we check if the tests passed by using grep.
          if grep -q "test result: FAILED" qemu-output.log; then
            echo "tests failed (QEMU exited abnormally)"
            exit 1
          else
            echo "all tests passed"
          fi