release-image: Remap UID within the image before handling $DOCKER_USER

If do not update the UID within the passwd database to match whatever
uid the container is being ran as, then sudo will not work when renaming
the user to match $DOCKER_USER as it will complain about the current
user being non-existent.

Author: nhooyr

ci/release-image/entrypoint.sh

@@ -1,7 +1,11 @@
 #!/bin/sh
 set -eu
 
-if [ "${DOCKER_USER-}" ] && [ "$DOCKER_USER" != "$USER" ]; then
+# We do this first to ensure sudo works below when renaming the user.
+# Otherwise the current container UID may not exist in the passwd database.
+eval "$(fixuid -q)"
+
+if [ "${DOCKER_USER-}" ]; then
   echo "$DOCKER_USER ALL=(ALL) NOPASSWD:ALL" | sudo tee -a /etc/sudoers.d/nopasswd > /dev/null
   # Unfortunately we cannot change $HOME as we cannot move any bind mounts
   # nor can we bind mount $HOME into a new home as that requires a privileged container.
@@ -11,7 +15,6 @@ if [ "${DOCKER_USER-}" ] && [ "$DOCKER_USER" != "$USER" ]; then
   USER="$DOCKER_USER"
 
   sudo sed -i "/coder/d" /etc/sudoers.d/nopasswd
-  sudo sed -i "s/coder/$DOCKER_USER/g" /etc/fixuid/config.yml
 fi
 
-dumb-init fixuid -q /usr/bin/code-server "$@"
+dumb-init /usr/bin/code-server "$@"