[dockerfile] Fix container after moving urllib3 to pip

This dockerfile was not updated after the move from getting urllib3 via
pip instead of through a system dependency with `apt`.

The toolchain download needs to be moved to *after* we download all the
Python dependencies with pip, so that this can continue to work. This
commit performs this move, and also modifies the ownership of `/tools`
so that the user can correctly install the toolchain later. We do not
just create this file as root and give access to the dev user because
the `get-toolchain.py` script depends on the presence of the directory
to determine install vs. upgrade semantics.

Signed-off-by: Alex Jones <[email protected]>

Author: AlexJones0

util/container/Dockerfile

@@ -63,11 +63,6 @@ RUN sed -i -e '/^$/d' -e '/^#/d' -e 's/#.*//' /tmp/apt-requirements.txt \
     && apt-get clean; \
     rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/* /usr/share/doc/*
 
-# RISC-V device toolchain
-COPY util/get-toolchain.py /tmp/get-toolchain.py
-RUN /tmp/get-toolchain.py -r ${RISCV_TOOLCHAIN_TAR_VERSION} \
-    && rm -f /tmp/get-toolchain.py
-
 # Install and configure clang and llvm tools for coverage measurements.
 # Note: Some commands listed below are missing in 13.0.1 and cause warnings during
 # build. These are kept intentionally since we plan to use them in the future, e.g.
@@ -143,6 +138,11 @@ RUN groupadd dev \
     && usermod -p '*' dev \
     && passwd -u dev
 
+# Give the dev user access to `/tools` so they can install the toolchain later.
+RUN mkdir -p /tools \
+    && chown dev:dev /tools \
+    && chmod 775 /tools
+
 # All subsequent steps are performed as user.
 USER dev:dev
 
@@ -160,6 +160,11 @@ RUN python3 -m pip install --user -U pip "setuptools<66.0.0" \
         --no-warn-script-location \
     && rm -f /tmp/python-requirements.txt
 
+# Get the RISC-V device toolchain
+COPY --chown=dev:dev util/get-toolchain.py /tmp/get-toolchain.py
+RUN /tmp/get-toolchain.py -r ${RISCV_TOOLCHAIN_TAR_VERSION} \
+    && rm -f /tmp/get-toolchain.py
+
 USER root:root
 
 # Install bazel using bazelisk.