scripts/kernel-test: build initrd+kernel as user

Refactor code to build the initramfs and kernel as user, instead of
running related code as root. Put the smoke_test.log into /tmp instead
of the cache dir, so we don't write as root into the cache dir. We cat
it on error anyway, so we don't need to have it in the workspace.

Change-Id: I1670dd86f2670f42eb99e4527d483965d8222402

jenkins-common.sh

@@ -467,11 +467,12 @@ kernel_test_prepare() {
 	cp "$initrd_project_script" \
 		"$CACHE_DIR/kernel-test/initrd-project-script.sh"
 
+	fix_perms
+
+	# Build kernel and initramfs
 	docker run \
 		--rm \
-		--cap-add=NET_ADMIN \
-		$(docker_kvm_param) \
-		--device /dev/net/tun:/dev/net/tun \
+		--user "build" \
 		-v "$CACHE_DIR:/cache" \
 		-v "$KERNEL_TEST_DIR:/kernel-test:ro" \
 		-e "KERNEL_BRANCH=$KERNEL_BRANCH" \
@@ -480,11 +481,25 @@ kernel_test_prepare() {
 		-e "KERNEL_REMOTE_NAME=$KERNEL_REMOTE_NAME" \
 		-e "KERNEL_URL=$KERNEL_URL" \
 		-e "KERNEL_SKIP_REBUILD=$KERNEL_SKIP_REBUILD" \
-		-e "KERNEL_SKIP_SMOKE_TEST=$KERNEL_SKIP_SMOKE_TEST" \
 		$DOCKER_ARGS \
 		"$@" \
 		"$docker_image" \
 		"/kernel-test/prepare.sh"
+
+	# Smoke test
+	if [ "$KERNEL_SKIP_SMOKE_TEST" != 1 ]; then
+		docker run \
+			--rm \
+			--cap-add=NET_ADMIN \
+			$(docker_kvm_param) \
+			--device /dev/net/tun:/dev/net/tun \
+			-v "$CACHE_DIR:/cache" \
+			-v "$KERNEL_TEST_DIR:/kernel-test:ro" \
+			$DOCKER_ARGS \
+			"$@" \
+			"$docker_image" \
+			"/kernel-test/smoke-test.sh"
+	fi
 }
 
 # Wait until the linux kernel is booted inside QEMU inside docker, and the

scripts/kernel-test/prepare.sh

@@ -1,17 +1,6 @@
 #!/bin/sh -ex
 KERNEL_BUILD="${KERNEL_BUILD:-0}"
 
-# Test if the kernel boots up, and initd code runs through without error
-kernel_smoke_test() {
-	local log=/cache/kernel-test/smoke_test.log
-	/kernel-test/run-qemu.sh SMOKE_TEST > "$log" 2>&1 || true
-	if ! grep -q SMOKE_TEST_SUCCESS "$log"; then
-		cat "$log"
-		echo "ERROR: failed to boot the kernel and initrd in QEMU!"
-		exit 1
-	fi
-}
-
 /kernel-test/initrd-build.sh
 
 if [ "$KERNEL_BUILD" = 1 ]; then
@@ -19,7 +8,3 @@ if [ "$KERNEL_BUILD" = 1 ]; then
 else
 	cp /boot/vmlinuz-* /cache/kernel-test/linux
 fi
-
-if [ "$KERNEL_SKIP_SMOKE_TEST" != 1 ]; then
-	kernel_smoke_test
-fi

scripts/kernel-test/smoke-test.sh

@@ -0,0 +1,13 @@
+#!/bin/sh -ex
+# Test if the kernel boots up, and initd code runs through without error
+
+LOG=/tmp/smoke_test.log
+
+/kernel-test/run-qemu.sh SMOKE_TEST > "$LOG" 2>&1 || true
+
+if ! grep -q SMOKE_TEST_SUCCESS "$LOG"; then
+	cat "$LOG"
+	set +x
+	echo "ERROR: failed to boot the kernel and initrd in QEMU!"
+	exit 1
+fi