From 5afc16f275a1fdd48386a26d0f7b7389c456690a Mon Sep 17 00:00:00 2001
From: Rolf Neugebauer <rolf.neugebauer@docker.com>
Date: Sun, 22 Oct 2017 15:59:13 +0100
Subject: [PATCH] kernel: Enable building kernels without patches

Copying the entire local directory into the container allows
us to check for the existence of the patch directory and
only apply the patches if the directory exists.

An alternative would have been to re-arrange the patch directory
into a sub-directory, but in terms of copying wouldn't have
made that much if a difference.

Signed-off-by: Rolf Neugebauer <rolf.neugebauer@docker.com>
---
 kernel/Dockerfile         | 29 +++++++++++++++--------------
 kernel/Dockerfile.kconfig | 13 +++++++------
 2 files changed, 22 insertions(+), 20 deletions(-)

diff --git a/kernel/Dockerfile b/kernel/Dockerfile
index c4bc1e8b8..e8afe09d4 100644
--- a/kernel/Dockerfile
+++ b/kernel/Dockerfile
@@ -41,11 +41,13 @@ ENV WIREGUARD_VERSION=0.0.20171017
 ENV WIREGUARD_SHA256=57b79a62874d9b99659a744513d4f6f9d88cb772deaa99e485b6fed3004a35cd
 ENV WIREGUARD_URL=https://git.zx2c4.com/WireGuard/snapshot/WireGuard-${WIREGUARD_VERSION}.tar.xz
 
-# PGP keys: 589DA6B1 (greg@kroah.com) & 6092693E (autosigner@kernel.org) & 00411886 (torvalds@linux-foundation.org)
-COPY keys.asc keys.asc
+# We copy the entire directory. This copies some unneeded files, but
+# allows us to check for the existence /patches-${KERNEL_SERIES} to
+# build kernels without patches.
+COPY / /
 
 # Download and verify kernel
-COPY sources/ /
+# PGP keys: 589DA6B1 (greg@kroah.com) & 6092693E (autosigner@kernel.org) & 00411886 (torvalds@linux-foundation.org)
 RUN curl -fsSLO ${KERNEL_SHA256_SUMS} && \
     gpg2 -q --import keys.asc && \
     gpg2 --verify sha256sums.asc && \
@@ -57,17 +59,17 @@ RUN curl -fsSLO ${KERNEL_SHA256_SUMS} && \
     gpg2 --verify linux-${KERNEL_VERSION}.tar.sign linux-${KERNEL_VERSION}.tar && \
     cat linux-${KERNEL_VERSION}.tar | tar --absolute-names -x && mv /linux-${KERNEL_VERSION} /linux
 
-# Apply local patches
-COPY patches-${KERNEL_SERIES} /patches
+# Apply local patches if present
 WORKDIR /linux
-RUN set -e && for patch in /patches/*.patch; do \
-        echo "Applying $patch"; \
-        patch -p1 < "$patch"; \
-    done
+RUN set -e && \
+    if [ -d /patches-${KERNEL_SERIES} ]; then \
+        for patch in /patches-${KERNEL_SERIES}/*.patch; do \
+            echo "Applying $patch"; \
+            patch -p1 < "$patch"; \
+        done; \
+    fi
 
 # Kernel config
-COPY kernel_config* /linux/
-
 RUN case $(uname -m) in \
     x86_64) \
         KERNEL_DEF_CONF=/linux/arch/x86/configs/x86_64_defconfig; \
@@ -76,15 +78,14 @@ RUN case $(uname -m) in \
         KERNEL_DEF_CONF=/linux/arch/arm64/configs/defconfig; \
         ;; \
     esac  && \
-    cp /linux/kernel_config-${KERNEL_SERIES}-$(uname -m) ${KERNEL_DEF_CONF}; \
+    cp /kernel_config-${KERNEL_SERIES}-$(uname -m) ${KERNEL_DEF_CONF}; \
     if [ -n "${EXTRA}" ]; then \
         sed -i "s/CONFIG_LOCALVERSION=\"-linuxkit\"/CONFIG_LOCALVERSION=\"-linuxkit${EXTRA}\"/" ${KERNEL_DEF_CONF}; \
         if [ "${EXTRA}" = "-dbg" ]; then \
             sed -i 's/CONFIG_PANIC_ON_OOPS=y/# CONFIG_PANIC_ON_OOPS is not set/' ${KERNEL_DEF_CONF}; \
         fi && \
-        cat /linux/kernel_config${EXTRA} >> ${KERNEL_DEF_CONF}; \
+        cat /kernel_config${EXTRA} >> ${KERNEL_DEF_CONF}; \
     fi && \
-    rm /linux/kernel_config* && \
     make defconfig && \
     make oldconfig && \
     if [ -z "${EXTRA}" ]; then diff .config ${KERNEL_DEF_CONF}; fi
diff --git a/kernel/Dockerfile.kconfig b/kernel/Dockerfile.kconfig
index 1aa108ead..a78bd19ff 100644
--- a/kernel/Dockerfile.kconfig
+++ b/kernel/Dockerfile.kconfig
@@ -10,8 +10,6 @@ RUN apk add \
 
 ARG KERNEL_VERSIONS
 
-# There is no simple way to copy directories with wild cards as needed
-# for patches-*. Copy the entire dir instead.
 COPY / /
 
 # Unpack kernels (download if not present)
@@ -27,10 +25,13 @@ RUN for VERSION in ${KERNEL_VERSIONS}; do \
         SERIES=${VERSION%.*}.x && \
         echo "Patching $VERSION" && \
         cd /linux-${VERSION} && \
-        set -e && for patch in /patches-${SERIES}/*.patch; do \
-            echo "Applying $patch" && \
-            patch -p1 < "$patch"; \
-        done && \
+        set -e && \
+            if [ -d /patches-${KERNEL_SERIES} ]; then \
+               for patch in /patches-${SERIES}/*.patch; do \
+                   echo "Applying $patch" && \
+                   patch -p1 < "$patch"; \
+               done; \
+            fi && \
         mv /kernel_config-${SERIES}-x86_64 arch/x86/configs/x86_64_defconfig && \
         mv /kernel_config-${SERIES}-aarch64 arch/arm64/configs/defconfig; \
     done