[mc] Add SKIP_OWNERSHIP_FIX option

For #104

minecraft-server/README.md

@@ -543,7 +543,7 @@ By default, server checks connecting players against Minecraft's account databas
 
     docker run -d -e ONLINE_MODE=FALSE ...
 
-## JVM Configuration
+## Miscellaneous Options
 
 ### Memory Limit
 
@@ -551,3 +551,7 @@ The Java memory limit can be adjusted using the `JVM_OPTS` environment variable,
 the setting shown in the example (max and min at 1024 MB):
 
     docker run -e 'JVM_OPTS=-Xmx1024M -Xms1024M' ...
+
+### /data ownership
+
+In order to adapt to differences in `UID` and `GID` settings the entry script will attempt to correct ownership and writability of the `/data` directory. This logic can be disabled by setting `-e SKIP_OWNERSHIP_FIX=TRUE`.

minecraft-server/start.sh

@@ -4,17 +4,19 @@ set -e
 usermod --uid $UID minecraft
 groupmod --gid $GID minecraft
 
-fix_ownership() {
-  dir=$1
-  if ! sudo -u minecraft test -w $dir; then
-    echo "Correcting writability of $dir ..."
-    chown -R minecraft:minecraft $dir
-    chmod -R u+w $dir
-  fi
-}
+if [ "$SKIP_OWNERSHIP_FIX" != "TRUE" ]; then
+  fix_ownership() {
+    dir=$1
+    if ! sudo -u minecraft test -w $dir; then
+      echo "Correcting writability of $dir ..."
+      chown -R minecraft:minecraft $dir
+      chmod -R u+w $dir
+    fi
+  }
 
-fix_ownership /data
-fix_ownership /home/minecraft
+  fix_ownership /data
+  fix_ownership /home/minecraft
+fi
 
 echo "Switching to user 'minecraft'"
 exec sudo -E -u minecraft /start-minecraft "$@"