Add makefile_goal.

Only for boot images.

Test: add one makefile_goal
Bug: 158537840
Change-Id: I88a006a1c7bfbf79f10f5360aae27a9bc267e42d
diff --git a/android/Android.bp b/android/Android.bp
index 487372b..c196b7a 100644
--- a/android/Android.bp
+++ b/android/Android.bp
@@ -23,6 +23,7 @@
         "filegroup.go",
         "hooks.go",
         "image.go",
+        "makefile_goal.go",
         "makevars.go",
         "metrics.go",
         "module.go",
diff --git a/android/makefile_goal.go b/android/makefile_goal.go
new file mode 100644
index 0000000..eae3976
--- /dev/null
+++ b/android/makefile_goal.go
@@ -0,0 +1,99 @@
+// Copyright 2020 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package android
+
+import (
+	"fmt"
+	"io"
+	"path/filepath"
+
+	"github.com/google/blueprint/proptools"
+)
+
+func init() {
+	RegisterModuleType("makefile_goal", MakefileGoalFactory)
+}
+
+type makefileGoalProperties struct {
+	// Sources.
+
+	// Makefile goal output file path, relative to PRODUCT_OUT.
+	Product_out_path *string
+}
+
+type makefileGoal struct {
+	ModuleBase
+
+	properties makefileGoalProperties
+
+	// Destination. Output file path of this module.
+	outputFilePath OutputPath
+}
+
+var _ AndroidMkEntriesProvider = (*makefileGoal)(nil)
+var _ OutputFileProducer = (*makefileGoal)(nil)
+
+// Input file of this makefile_goal module. Nil if none specified. May use variable names in makefiles.
+func (p *makefileGoal) inputPath() *string {
+	if p.properties.Product_out_path != nil {
+		return proptools.StringPtr(filepath.Join("$(PRODUCT_OUT)", proptools.String(p.properties.Product_out_path)))
+	}
+	return nil
+}
+
+// OutputFileProducer
+func (p *makefileGoal) OutputFiles(tag string) (Paths, error) {
+	if tag != "" {
+		return nil, fmt.Errorf("unsupported tag %q", tag)
+	}
+	return Paths{p.outputFilePath}, nil
+}
+
+// AndroidMkEntriesProvider
+func (p *makefileGoal) DepsMutator(ctx BottomUpMutatorContext) {
+	if p.inputPath() == nil {
+		ctx.PropertyErrorf("product_out_path", "Path relative to PRODUCT_OUT required")
+	}
+}
+
+func (p *makefileGoal) GenerateAndroidBuildActions(ctx ModuleContext) {
+	filename := filepath.Base(proptools.String(p.inputPath()))
+	p.outputFilePath = PathForModuleOut(ctx, filename).OutputPath
+
+	ctx.InstallFile(PathForModuleInstall(ctx, "etc"), ctx.ModuleName(), p.outputFilePath)
+}
+
+func (p *makefileGoal) AndroidMkEntries() []AndroidMkEntries {
+	return []AndroidMkEntries{AndroidMkEntries{
+		Class:      "ETC",
+		OutputFile: OptionalPathForPath(p.outputFilePath),
+		ExtraFooters: []AndroidMkExtraFootersFunc{
+			func(w io.Writer, name, prefix, moduleDir string, entries *AndroidMkEntries) {
+				// Can't use Cp because inputPath() is not a valid Path.
+				fmt.Fprintf(w, "$(eval $(call copy-one-file,%s,%s))\n", proptools.String(p.inputPath()), p.outputFilePath)
+			},
+		},
+	}}
+}
+
+// Import a Makefile goal to Soong by copying the file built by
+// the goal to a path visible to Soong. This rule only works on boot images.
+func MakefileGoalFactory() Module {
+	module := &makefileGoal{}
+	module.AddProperties(&module.properties)
+	// This module is device-only
+	InitAndroidArchModule(module, DeviceSupported, MultilibFirst)
+	return module
+}
diff --git a/android/neverallow.go b/android/neverallow.go
index 526d399..73829f1 100644
--- a/android/neverallow.go
+++ b/android/neverallow.go
@@ -56,6 +56,7 @@
 	AddNeverAllowRules(createJavaDeviceForHostRules()...)
 	AddNeverAllowRules(createCcSdkVariantRules()...)
 	AddNeverAllowRules(createUncompressDexRules()...)
+	AddNeverAllowRules(createMakefileGoalRules()...)
 }
 
 // Add a NeverAllow rule to the set of rules to apply.
@@ -231,6 +232,15 @@
 	}
 }
 
+func createMakefileGoalRules() []Rule {
+	return []Rule{
+		NeverAllow().
+			ModuleType("makefile_goal").
+			WithoutMatcher("product_out_path", Regexp("^boot[0-9a-zA-Z.-]*[.]img$")).
+			Because("Only boot images may be imported as a makefile goal."),
+	}
+}
+
 func neverallowMutator(ctx BottomUpMutatorContext) {
 	m, ok := ctx.Module().(Module)
 	if !ok {
diff --git a/android/neverallow_test.go b/android/neverallow_test.go
index 45d36a6..56a07dc 100644
--- a/android/neverallow_test.go
+++ b/android/neverallow_test.go
@@ -326,6 +326,20 @@
 			"module \"outside_art_libraries\": violates neverallow",
 		},
 	},
+	{
+		name: "disallowed makefile_goal",
+		fs: map[string][]byte{
+			"Android.bp": []byte(`
+				makefile_goal {
+					name: "foo",
+					product_out_path: "boot/trap.img"
+				}
+			`),
+		},
+		expectedErrors: []string{
+			"Only boot images may be imported as a makefile goal.",
+		},
+	},
 }
 
 func TestNeverallow(t *testing.T) {
@@ -350,6 +364,7 @@
 	ctx.RegisterModuleType("java_library", newMockJavaLibraryModule)
 	ctx.RegisterModuleType("java_library_host", newMockJavaLibraryModule)
 	ctx.RegisterModuleType("java_device_for_host", newMockJavaLibraryModule)
+	ctx.RegisterModuleType("makefile_goal", newMockMakefileGoalModule)
 	ctx.PostDepsMutators(RegisterNeverallowMutator)
 	ctx.Register(config)
 
@@ -438,3 +453,22 @@
 
 func (p *mockJavaLibraryModule) GenerateAndroidBuildActions(ModuleContext) {
 }
+
+type mockMakefileGoalProperties struct {
+	Product_out_path *string
+}
+
+type mockMakefileGoalModule struct {
+	ModuleBase
+	properties mockMakefileGoalProperties
+}
+
+func newMockMakefileGoalModule() Module {
+	m := &mockMakefileGoalModule{}
+	m.AddProperties(&m.properties)
+	InitAndroidModule(m)
+	return m
+}
+
+func (p *mockMakefileGoalModule) GenerateAndroidBuildActions(ModuleContext) {
+}