From 463cc62b75f6dcc3e977150134fe5a01edecdb7e Mon Sep 17 00:00:00 2001
From: Geoff Bourne <itzgeoff@gmail.com>
Date: Sat, 2 Sep 2017 12:24:09 -0500
Subject: [PATCH] [mc] Check writability of /data

Document JVM_OPTS
For #176 and #177
---
 minecraft-server/README.md          | 8 +++++++-
 minecraft-server/start-minecraft.sh | 9 +++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/minecraft-server/README.md b/minecraft-server/README.md
index 681c61e1..647421cc 100644
--- a/minecraft-server/README.md
+++ b/minecraft-server/README.md
@@ -683,7 +683,7 @@ To use this option pass the environment variable `REMOVE_OLD_MODS="TRUE"`, such
 
 **NOTE:** This option will be taken into account only when option `MODPACK` is also used.
 
-**WARNING:** All content of the `mods` or `plugins` directory will be deleted 
+**WARNING:** All content of the `mods` or `plugins` directory will be deleted
 before unpacking new content from the zip file.
 
 ### Online mode
@@ -710,3 +710,9 @@ The values of all three are passed directly to the JVM and support format/units
 ### /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`.
+
+### JVM Options
+
+General JVM options can be passed to the Minecraft Server invocation by passing a `JVM_OPTS`
+environment variable. Options like `-X` that need to proceed general JVM options can be passed
+via a `JVM_XX_OPTS` environment variable.
diff --git a/minecraft-server/start-minecraft.sh b/minecraft-server/start-minecraft.sh
index a1f019e1..54afc7c8 100755
--- a/minecraft-server/start-minecraft.sh
+++ b/minecraft-server/start-minecraft.sh
@@ -9,6 +9,10 @@ if [ ! -e /data/eula.txt ]; then
   if [ "$EULA" != "" ]; then
     echo "# Generated via Docker on $(date)" > eula.txt
     echo "eula=$EULA" >> eula.txt
+    if [ $? != 0 ]; then
+      echo "ERROR: unable to write eula to /data. Please make sure attached directory is writable by uid=${UID}"
+      exit 2
+    fi
   else
     echo ""
     echo "Please accept the Minecraft EULA at"
@@ -20,6 +24,11 @@ if [ ! -e /data/eula.txt ]; then
   fi
 fi
 
+if ! touch /data/.verify_access; then
+  echo "ERROR: /data doesn't seem to be writable. Please make sure attached directory is writable by uid=${UID} "
+  exit 2
+fi
+
 SERVER_PROPERTIES=/data/server.properties
 FTB_DIR=/data/FeedTheBeast
 VERSIONS_JSON=https://launchermeta.mojang.com/mc/game/version_manifest.json