Fetch all EC2 metadata / user data in the initrd

Since we're already fetching one datum, we may as well fetch the
others needed by fetch-ec2-data. This also eliminates the dependency
on wget.

nixos/modules/virtualisation/amazon-image.nix

@@ -57,8 +57,7 @@ let cfg = config.ec2; in
     boot.initrd.postMountCommands =
       ''
         metaDir=$targetRoot/etc/ec2-metadata
-        mkdir -m 0755 -p $targetRoot/etc
-        mkdir -m 0700 -p "$metaDir"
+        mkdir -m 0755 -p "$metaDir"
 
         echo "getting EC2 instance metadata..."
 
@@ -66,6 +65,19 @@ let cfg = config.ec2; in
           wget -q -O "$metaDir/ami-manifest-path" http://169.254.169.254/1.0/meta-data/ami-manifest-path
         fi
 
+        if ! [ -e "$metaDir/user-data" ]; then
+          wget -q -O "$metaDir/user-data" http://169.254.169.254/1.0/user-data
+          chmod 600 "$metaDir/user-data"
+        fi
+
+        if ! [ -e "$metaDir/hostname" ]; then
+          wget -q -O "$metaDir/hostname" http://169.254.169.254/1.0/meta-data/hostname
+        fi
+
+        if ! [ -e "$metaDir/public-keys-0-openssh-key" ]; then
+          wget -q -O "$metaDir/public-keys-0-openssh-key" http://169.254.169.254/1.0/meta-data/public-keys/0/openssh-key
+        fi
+
         diskNr=0
         diskForUnionfs=
         for device in /dev/xvd[abcde]*; do