add more build examples

build/Dockerfile.ubuntu-env-override

@@ -0,0 +1,25 @@
+ARG  REGISTRY=docker.io
+ARG  BASE=library/ubuntu:20.04
+
+FROM ${REGISTRY}/${BASE} as base
+
+FROM base as builder
+RUN  ln -svf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime && apt update && apt install build-essential libseccomp-dev curl pkg-config -y
+RUN  curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | bash -s - -y
+COPY Cargo.toml Cargo.lock build.rs /src/
+COPY src /src/src
+COPY x2t-sandbox-rulegen /src/x2t-sandbox-rulegen
+WORKDIR /src
+ARG  X2T_SYSCALLS
+ENV  X2T_SYSCALLS=${X2T_SYSCALLS}
+RUN  test ! -z "${X2T_SYSCALLS}" || { echo please set X2T_SYSCALLS with --build-arg X2T_SYSCALLS="open:close:read:write:..."; exit 1; }
+RUN  /root/.cargo/bin/cargo build --release
+
+FROM base as runtime
+RUN  apt update && apt install libseccomp2 -y && rm -rf /var/apt
+COPY --from=builder /src/target/release/x2t-sandbox /usr/local/bin/x2t-sandbox
+
+FROM base as copy-to-data
+COPY --from=builder /src/target/release/x2t-sandbox /x2t-sandbox
+CMD  ["cp", "-v", "x2t-sandbox", "/data/x2t-sandbox"]
+