name: Build static rsync for Android

# Cross-compiles statically-linked rsync binaries with the Android NDK,
# suitable for dropping onto a phone (adb push / Termux) with no shared
# libraries. arm64-v8a covers all modern phones; armeabi-v7a covers older
# 32-bit devices. The binaries are uploaded as workflow artifacts.
#
# These are cross-compiled, so the test suite can't run here; we sanity
# check that each binary is the right architecture, is static, and that
# it executes (`--version`) under qemu-user.

on:
  push:
    branches: [ master ]
    paths-ignore:
      - '.github/workflows/*.yml'
      - '!.github/workflows/android-static-build.yml'
  pull_request:
    branches: [ master ]
    paths-ignore:
      - '.github/workflows/*.yml'
      - '!.github/workflows/android-static-build.yml'
  schedule:
    - cron: '42 8 * * *'
  workflow_dispatch:

env:
  # Minimum supported API level. 24 (Android 7.0) runs on every modern
  # phone while keeping broad reach; bump if you need newer Bionic APIs.
  ANDROID_API: 24

jobs:
  build:
    runs-on: ubuntu-latest
    name: ${{ matrix.abi }}
    strategy:
      fail-fast: false
      matrix:
        include:
          - abi: arm64-v8a       # modern phones
            triple: aarch64-linux-android
            qemu: qemu-aarch64-static
          - abi: armeabi-v7a     # older 32-bit phones
            triple: armv7a-linux-androideabi
            qemu: qemu-arm-static
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Install build prerequisites
        run: sudo apt-get update && sudo apt-get install -y autoconf automake gawk qemu-user-static

      - name: Configure and build (${{ matrix.abi }})
        shell: bash
        run: |
          set -euo pipefail
          NDK="${ANDROID_NDK_LATEST_HOME:-$ANDROID_NDK_ROOT}"
          TC="$NDK/toolchains/llvm/prebuilt/linux-x86_64/bin"
          export CC="$TC/${{ matrix.triple }}${ANDROID_API}-clang"
          export AR="$TC/llvm-ar" RANLIB="$TC/llvm-ranlib" STRIP="$TC/llvm-strip"
          export CFLAGS="-O2" LDFLAGS="-static"

          # Bionic doesn't declare lchmod()/lutimes() until API 36, but the
          # symbols link, so configure mis-detects them -- force them off so
          # rsync uses its fallbacks. The other cache vars restore values
          # that configure can't probe when cross-compiling (Android runs a
          # normal Linux kernel, so these match the native Linux result).
          export ac_cv_func_lchmod=no ac_cv_func_lutimes=no \
                 rsync_cv_HAVE_SOCKETPAIR=yes \
                 rsync_cv_MKNOD_CREATES_FIFOS=yes \
                 rsync_cv_MKNOD_CREATES_SOCKETS=yes

          # Self-contained build: drop optional external libraries so the
          # static binary needs nothing at runtime. rsync keeps md5/md4
          # checksums and its bundled zlib.
          ./configure --host=${{ matrix.triple }} --build=x86_64-pc-linux-gnu \
            --enable-ipv6 \
            --disable-zstd --disable-lz4 --disable-xxhash --disable-openssl \
            --disable-iconv --disable-iconv-open \
            --disable-acl-support --disable-xattr-support \
            --disable-md2man --disable-roll-simd \
            --with-included-popt --with-included-zlib

          # Generate the awk-built headers serially first so the parallel
          # build can't race on proto.h <- daemon-parm.h.
          make proto.h
          make -j"$(nproc)" rsync
          "$STRIP" rsync

      - name: Verify binary
        shell: bash
        run: |
          set -euo pipefail
          file rsync
          # Gate: must be a statically-linked executable (no interpreter).
          file rsync | grep -q "statically linked"
          if file rsync | grep -q "dynamically linked"; then
            echo "ERROR: binary is not static" >&2; exit 1
          fi
          # Best-effort: confirm it actually runs under qemu-user.
          ${{ matrix.qemu }} ./rsync --version | head -3 || \
            echo "WARNING: qemu smoke test did not run cleanly (check on a real device)"

      - name: Package
        shell: bash
        run: |
          set -euo pipefail
          VER=$(sed -n 's/.*RSYNC_VERSION "\([^"]*\)".*/\1/p' version.h)
          out="rsync-${VER}-android-${{ matrix.abi }}"
          mkdir -p dist
          cp rsync "dist/$out"
          ( cd dist && sha256sum "$out" > "$out.sha256" )
          echo "ARTIFACT_NAME=rsync-android-${{ matrix.abi }}" >>"$GITHUB_ENV"

      - name: Upload artifact
        uses: actions/upload-artifact@v4
        with:
          name: ${{ env.ARTIFACT_NAME }}
          path: dist/