Integrate with Dapper, cross-compile in Alpine

Dockerfile.dapper

@@ -44,7 +44,7 @@ ARG SELINUX=true
 ENV SELINUX $SELINUX
 
 ENV DAPPER_RUN_ARGS --privileged -v k3s-cache:/go/src/github.com/k3s-io/k3s/.cache -v trivy-cache:/root/.cache/trivy
-ENV DAPPER_ENV REPO TAG DRONE_TAG IMAGE_NAME SKIP_VALIDATE SKIP_AIRGAP AWS_SECRET_ACCESS_KEY AWS_ACCESS_KEY_ID GITHUB_TOKEN GOLANG GOCOVER DEBUG
+ENV DAPPER_ENV REPO TAG DRONE_TAG IMAGE_NAME ARCH SKIP_VALIDATE SKIP_IMAGE SKIP_AIRGAP AWS_SECRET_ACCESS_KEY AWS_ACCESS_KEY_ID GITHUB_TOKEN GOLANG GOCOVER DEBUG
 ENV DAPPER_SOURCE /go/src/github.com/k3s-io/k3s/
 ENV DAPPER_OUTPUT ./bin ./dist ./build/out ./build/static ./pkg/static ./pkg/deploy
 

scripts/build

@@ -101,8 +101,8 @@ fi
 if [ ${ARCH} = riscv64 ]; then
     export GOARCH="riscv64"
     # These are needed as we are cross-compiling
-    export CC=riscv64-linux-gnu-gcc
-    export PKG_CONFIG_PATH=/usr/lib/riscv64-linux-gnu/pkgconfig/
+    export CC="riscv64-alpine-linux-musl-gcc"
+    export PKG_CONFIG_PATH=/home/builder/sysroot-riscv64/usr/lib/pkgconfig/
 fi
 
 rm -f \

scripts/ci

@@ -6,6 +6,9 @@ pushd $SCRIPT_DIR
 
 ./download
 ./validate
+if [ ${ARCH} = riscv64 ]; then
+    ./prepare-cross
+fi
 ./build
 ./package
 

scripts/package

@@ -8,7 +8,9 @@ if [ ! -e ../bin/containerd ]; then
 fi
 
 ./package-cli
-./package-image
+if [ -z "$SKIP_IMAGE" ]; then
+    ./package-image
+fi
 if [ -z "$SKIP_AIRGAP" ]; then
     ./package-airgap
 fi

scripts/prepare-cross

@@ -0,0 +1,39 @@
+#/bin/bash
+
+# This script prepare a cross-compilation environment for $ARCH
+
+if [ -z "$ARCH" ]; then
+    echo "Error: ARCH not defined"
+    exit 1;
+fi
+
+if [ "$ARCH" != "riscv64" ]; then
+    echo "Error: Cross-compilation only available for riscv64"
+    exit 1;
+fi
+
+if [ "$ARCH" = "riscv64" ]; then
+    ALPINE_APK_REPO=https://dl-cdn.alpinelinux.org/alpine/edge/main
+fi
+
+# Build packages for cross-compiling (bootstrap.sh requires a non-root user)
+adduser -D builder
+addgroup builder abuild
+
+su builder -c "abuild-keygen -an"
+cp ~builder/.abuild/builder-*.rsa.pub /etc/apk/keys/
+
+ALPINE_VERSION=$(. /etc/os-release; echo $VERSION_ID | cut -f1,2 -d.)
+su builder -c "cd; git clone --single-branch --branch=$ALPINE_VERSION-stable --depth 1 https://github.com/alpinelinux/aports"
+sed -i "/Cross building base system/i exit 0\n" /home/builder/aports/scripts/bootstrap.sh
+apk update
+su builder -c "CBUILDROOT=~/sysroot-$ARCH ~/aports/scripts/bootstrap.sh $ARCH"
+
+# Install the cross-compiler in the host
+apk -X /home/builder/packages/main add gcc-$ARCH
+
+# Install headers and libraries in the gcc sysroot (upstream packages)
+apk -X $ALPINE_APK_REPO -U --allow-untrusted \
+    -p /home/builder/sysroot-$ARCH --arch $ARCH add \
+    musl musl-dev linux-headers libseccomp-dev libseccomp-static sqlite-dev sqlite-static zlib-static libgcc
+sed -i "s/^prefix=.*/prefix=\/home\/builder\/sysroot-$ARCH\/usr/g" /home/builder/sysroot-riscv64/usr/lib/pkgconfig/libseccomp.pc