Add cross compilation support (#85)

Add support for cross-compiling curl-impersonate.

Cross compiling can now be done using the '--host' flag to the configure
script. This will make sure that all sub-components are cross-compiled.
In addition, compiling for a different system requires explicitly
specifying multiple paths used by curl (e.g. for certificates). These
options were added to the configure script as well.

The build and test CI workflow will now attempt to cross-compile
curl-impersonate to ARM64 (aarch64), and upload this binary to the
GitHub release page.

Add the 'configure' script generated by autoconf and its dependencies to
the repository to save the users from having to run 'autoconf' manually.

.github/workflows/build-and-test-make.yml

@@ -21,15 +21,23 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-20.04, macos-11]
+        arch: [x86_64]
         include:
           - os: ubuntu-20.04
+            arch: x86_64
+            host: x86_64-linux-gnu
+            capture_interface: eth0
+            make: make
+          - os: ubuntu-20.04
+            arch: aarch64
+            host: aarch64-linux-gnu
             capture_interface: eth0
             make: make
-            release_name: x86_64-linux-gnu
           - os: macos-11
+            arch: x86_64
+            host: x86_64-macos
             capture_interface: en0
             make: gmake
-            release_name: x86_64-macos
     steps:
       - uses: actions/setup-python@v3
 
@@ -45,6 +53,11 @@ jobs:
           # More dependencies for the tests
           sudo apt-get install tcpdump nghttp2-server libnss3
 
+      - name: Install Ubuntu dependencies (aarch64)
+        if: matrix.arch == 'aarch64'
+        run: |
+          sudo apt-get install gcc-aarch64-linux-gnu g++-aarch64-linux-gnu
+
       - name: Install macOS dependencies
         if: matrix.os == 'macos-11'
         run: |
@@ -69,12 +82,38 @@ jobs:
         run: |
           pip3 install -r tests/requirements.txt
 
-      - name: Run configure script
+      # When cross compiling we need to build zlib first.
+      - name: Build zlib
+        run: |
+          curl -LO https://zlib.net/zlib-1.2.12.tar.gz
+          tar xf zlib-1.2.12.tar.gz
+          cd zlib-1.2.12
+          CHOST=${{ matrix.host }} ./configure --prefix=${{ runner.temp }}/zlib
+          make
+          make install
+          # Make sure curl will link with libz.so.1 and not libz.so
+          rm -f ${{ runner.temp }}/zlib/lib/libz.so
+
+      - name: Run configure script
+        if: matrix.arch == 'x86_64'
         run: |
-          autoconf
           mkdir ${{ runner.temp }}/install
           ./configure --prefix=${{ runner.temp }}/install
 
+      # When cross compiling a more complicated configuration is needed, since
+      # curl's configure script can't figure out where some files and libraries
+      # are located. The locations used here are the ones used by Ubuntu.
+      - name: Run configure script (cross compiling)
+        if: matrix.arch != 'x86_64'
+        run: |
+          mkdir ${{ runner.temp }}/install
+          ./configure --prefix=${{ runner.temp }}/install \
+                      --host=${{ matrix.host }} \
+                      --with-zlib=${{ runner.temp }}/zlib \
+                      --with-ca-path=/etc/ssl/certs \
+                      --with-ca-bundle=/etc/ssl/certs/ca-certificates.crt \
+                      --with-libnssckbi=/usr/lib/${{ matrix.host }}/nss
+
       # Cache the build of BoringSSL, which is the longest part of the build
       # We must cache the .zip as well, otherwise the Makefile will
       # rebuild BoringSSL. This whole thing is a bit hacky, but necessary to
@@ -83,14 +122,14 @@ jobs:
         uses: actions/cache@v3
         with:
           path: boringssl.zip
-          key: ${{ runner.os }}-boring-source-${{ env.BORING_SSL_COMMIT }}
+          key: ${{ runner.os }}-${{ matrix.arch }}-boring-source-${{ env.BORING_SSL_COMMIT }}
 
       - name: Cache BoringSSL build
         id: cache-boringssl
         uses: actions/cache@v3
         with:
           path: boringssl/build
-          key: ${{ runner.os }}-boring-build-${{ env.BORING_SSL_COMMIT }}-${{ hashFiles('chrome/patches/boringssl*.patch') }}
+          key: ${{ runner.os }}-${{ matrix.arch }}-boring-build-${{ env.BORING_SSL_COMMIT }}-${{ hashFiles('chrome/patches/boringssl*.patch') }}
 
       # Trick the Makefile into skipping the BoringSSL build step
       # if it was found in the cache. See Makefile.in
@@ -114,14 +153,14 @@ jobs:
         uses: actions/cache@v3
         with:
           path: ${{ env.NSS_VERSION }}.tar.gz
-          key: ${{ runner.os }}-nss-source-${{ env.NSS_VERSION }}
+          key: ${{ runner.os }}-${{ matrix.arch }}-nss-source-${{ env.NSS_VERSION }}
 
       - name: Cache NSS build
         id: cache-nss
         uses: actions/cache@v3
         with:
           path: ${{ env.NSS_VERSION }}/dist
-          key: ${{ runner.os }}-nss-build-${{ env.NSS_VERSION }}
+          key: ${{ runner.os }}-${{ matrix.arch }}-nss-build-${{ env.NSS_VERSION }}
 
       # Trick the Makefile into skipping the NSS build step
       # if it was found in the cache.
@@ -138,11 +177,15 @@ jobs:
           ${{ matrix.make }} firefox-install
     
       - name: Prepare the tests
+        if: matrix.arch == 'x86_64'
         run: |
           # Compile 'minicurl' which is used by the tests
           gcc -Wall -Werror -o ${{ runner.temp }}/install/bin/minicurl tests/minicurl.c `curl-config --libs`
 
+      # For now we can only run the tests when not cross compiling, since the
+      # tests run the curl-impersonate binary locally.
       - name: Run the tests
+        if: matrix.arch == 'x86_64'
         run: |
           cd tests
           # sudo is needed for capturing packets
@@ -154,18 +197,37 @@ jobs:
         if: startsWith(github.ref, 'refs/tags/')
         run: |
             cd ${{ runner.temp }}/install/lib
-            tar -c -z -f ${{ runner.temp }}/libcurl-impersonate-${{ github.ref_name }}.${{ matrix.release_name }}.tar.gz libcurl-impersonate*
-            echo "release_file_lib=${{ runner.temp }}/libcurl-impersonate-${{ github.ref_name }}.${{ matrix.release_name }}.tar.gz" >> $GITHUB_ENV
+            tar -c -z -f ${{ runner.temp }}/libcurl-impersonate-${{ github.ref_name }}.${{ matrix.host }}.tar.gz libcurl-impersonate*
+            echo "release_file_lib=${{ runner.temp }}/libcurl-impersonate-${{ github.ref_name }}.${{ matrix.host }}.tar.gz" >> $GITHUB_ENV
 
-       # Recompile curl-impersonate statically.
-      - name: Recompile statically
+      - name: Clean build
         if: startsWith(github.ref, 'refs/tags/')
         run: |
           ${{ matrix.make }} chrome-clean
           ${{ matrix.make }} firefox-clean
           rm -Rf ${{ runner.temp }}/install
           mkdir ${{ runner.temp }}/install
+
+       # Recompile curl-impersonate statically when doing a release.
+      - name: Reconfigure statically
+        if: startsWith(github.ref, 'refs/tags/') && matrix.arch == 'x86_64'
+        run: |
           ./configure --prefix=${{ runner.temp }}/install --enable-static
+
+      - name: Reconfigure statically (cross compiling)
+        if: startsWith(github.ref, 'refs/tags/') && matrix.arch != 'x86_64'
+        run: |
+          ./configure --prefix=${{ runner.temp }}/install \
+                      --enable-static \
+                      --host=${{ matrix.host }} \
+                      --with-zlib=${{ runner.temp }}/zlib \
+                      --with-ca-path=/etc/ssl/certs \
+                      --with-ca-bundle=/etc/ssl/certs/ca-certificates.crt \
+                      --with-libnssckbi=/usr/lib/${{ matrix.host }}/nss
+
+      - name: Rebuild statically
+        if: startsWith(github.ref, 'refs/tags/')
+        run: |
           ${{ matrix.make }} chrome-build
           ${{ matrix.make }} chrome-checkbuild
           ${{ matrix.make }} chrome-install-strip
@@ -177,8 +239,8 @@ jobs:
         if: startsWith(github.ref, 'refs/tags/')
         run: |
           cd ${{ runner.temp }}/install/bin
-          tar -c -z -f ${{ runner.temp }}/curl-impersonate-${{ github.ref_name }}.${{ matrix.release_name }}.tar.gz curl-impersonate-ff curl-impersonate-chrome curl_*
-          echo "release_file_bin=${{ runner.temp }}/curl-impersonate-${{ github.ref_name }}.${{ matrix.release_name }}.tar.gz" >> $GITHUB_ENV
+          tar -c -z -f ${{ runner.temp }}/curl-impersonate-${{ github.ref_name }}.${{ matrix.host }}.tar.gz curl-impersonate-ff curl-impersonate-chrome curl_*
+          echo "release_file_bin=${{ runner.temp }}/curl-impersonate-${{ github.ref_name }}.${{ matrix.host }}.tar.gz" >> $GITHUB_ENV
 
       - name: Upload release files
         uses: softprops/action-gh-release@v1