uboot: (firmwareOdroidC2/C4) don't invoke patch tool, use patches = [] instead

https://github.com/NixOS/nixpkgs/blob/master/pkgs/stdenv/generic/setup.sh#L948
this can do it nicely.

Signed-off-by: Anton Arapov <anton@deadbeef.mx>

nixos/modules/virtualisation/ec2-metadata-fetcher.nix

@@ -0,0 +1,77 @@
+{ curl, targetRoot, wgetExtraOptions }:
+# Note: be very cautious about dependencies, each dependency grows
+# the closure of the initrd. Ideally we would not even require curl,
+# but there is no reasonable way to send an HTTP PUT request without
+# it. Note: do not be fooled: the wget referenced in this script
+# is busybox's wget, not the fully featured one with --method support.
+#
+# Make sure that every package you depend on here is already listed as
+# a channel blocker for both the full-sized and small channels.
+# Otherwise, we risk breaking user deploys in released channels.
+#
+# Also note: OpenStack's metadata service for its instances aims to be
+# compatible with the EC2 IMDS. Where possible, try to keep the set of
+# fetched metadata in sync with ./openstack-metadata-fetcher.nix .
+''
+  metaDir=${targetRoot}etc/ec2-metadata
+  mkdir -m 0755 -p "$metaDir"
+  rm -f "$metaDir/*"
+
+  get_imds_token() {
+    # retry-delay of 1 selected to give the system a second to get going,
+    # but not add a lot to the bootup time
+    ${curl}/bin/curl \
+      -v \
+      --retry 3 \
+      --retry-delay 1 \
+      --fail \
+      -X PUT \
+      --connect-timeout 1 \
+      -H "X-aws-ec2-metadata-token-ttl-seconds: 600" \
+      http://169.254.169.254/latest/api/token
+  }
+
+  preflight_imds_token() {
+    # retry-delay of 1 selected to give the system a second to get going,
+    # but not add a lot to the bootup time
+    ${curl}/bin/curl \
+      -v \
+      --retry 3 \
+      --retry-delay 1 \
+      --fail \
+      --connect-timeout 1 \
+      -H "X-aws-ec2-metadata-token: $IMDS_TOKEN" \
+      http://169.254.169.254/1.0/meta-data/instance-id
+  }
+
+  try=1
+  while [ $try -le 3 ]; do
+    echo "(attempt $try/3) getting an EC2 instance metadata service v2 token..."
+    IMDS_TOKEN=$(get_imds_token) && break
+    try=$((try + 1))
+    sleep 1
+  done
+
+  if [ "x$IMDS_TOKEN" == "x" ]; then
+    echo "failed to fetch an IMDS2v token."
+  fi
+
+  try=1
+  while [ $try -le 10 ]; do
+    echo "(attempt $try/10) validating the EC2 instance metadata service v2 token..."
+    preflight_imds_token && break
+    try=$((try + 1))
+    sleep 1
+  done
+
+  echo "getting EC2 instance metadata..."
+
+  wget_imds() {
+    wget ${wgetExtraOptions} --header "X-aws-ec2-metadata-token: $IMDS_TOKEN" "$@";
+  }
+
+  wget_imds -O "$metaDir/ami-manifest-path" http://169.254.169.254/1.0/meta-data/ami-manifest-path
+  (umask 077 && wget_imds -O "$metaDir/user-data" http://169.254.169.254/1.0/user-data)
+  wget_imds -O "$metaDir/hostname" http://169.254.169.254/1.0/meta-data/hostname
+  wget_imds -O "$metaDir/public-keys-0-openssh-key" http://169.254.169.254/1.0/meta-data/public-keys/0/openssh-key
+''