fix docker bind mount permission issues

builders/Linux/Dockerfile

@@ -38,7 +38,7 @@ ENV DEBIAN_FRONTEND=noninteractive
 ENV LANG=en_US.UTF-8
 ENV LC_ALL=C.UTF-8
 RUN apt-get -y update \
-    && apt-get -y install sudo build-essential cmake ninja-build git clang clang-13 clang-format iwyu \
+    && apt-get -y install sudo gosu build-essential cmake ninja-build git clang clang-13 clang-format iwyu \
     libglx-mesa0 libglvnd-dev libxkbcommon-dev libxkbcommon-x11-0 libpulse-dev libxcb1 libx11-xcb1 libxcb-glx0 libxcb-cursor0 \
     libxcb-icccm4 libxcb-image0 libxcb-render-util0 libxcb-keysyms1 libicu70 \
     libvulkan-dev mesa-vulkan-drivers \
@@ -58,8 +58,7 @@ RUN echo "mediafx ALL=(ALL) NOPASSWD: ALL" > /etc/sudoers.d/mediafx && chmod 044
 VOLUME /mediafx
 WORKDIR /mediafx/build/Linux
 
-COPY entrypoint.sh /entrypoint.sh
+COPY entrypoint.sh xvfb.sh /entrypoint/
 
-USER mediafx
-ENTRYPOINT ["/usr/bin/xvfb-run", "--server-args", "-screen 0 640x480x24 -nolisten unix", "--error-file", "/dev/stderr", "/entrypoint.sh"]
+ENTRYPOINT ["/entrypoint/entrypoint.sh"]
 CMD ["/mediafx/builders/Linux/mediafx-build.sh"]

builders/Linux/entrypoint.sh

@@ -1,4 +1,10 @@
 #!/usr/bin/env bash
 
-sudo mkdir -p /mediafx/build/Linux && sudo chown mediafx /mediafx/build/ /mediafx/build/Linux
-exec "$@"
+OLD_UID=$(id -u mediafx)
+NEW_UID=$(stat -c "%u" /mediafx/CMakeLists.txt)
+if [ ! -z "$NEW_UID" -a "$NEW_UID" != "0" -a "$OLD_UID" != "$NEW_UID" ]; then
+    usermod -u "$NEW_UID" -o mediafx
+fi
+
+mkdir -p /mediafx/build/Linux && chown -R mediafx /mediafx/build/Linux
+exec gosu mediafx /entrypoint/xvfb.sh "$@"

builders/Linux/xvfb.sh

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+
+exec /usr/bin/xvfb-run --server-args="-screen 0 640x480x24 -nolisten unix" --error-file=/tmp/xvfb.err "$@"
+[ -f /tmp/xvfb.err ] && cat /tmp/xvfb.err