filesystem/system_image.go

// Copyright (C) 2021 The Android Open Source Project
//
// 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 filesystem

import (
	"android/soong/android"
	"android/soong/linkerconfig"

	"path/filepath"
	"strings"

	"github.com/google/blueprint/proptools"
)

type systemImage struct {
	filesystem
}

var _ filesystemBuilder = (*systemImage)(nil)

// android_system_image is a specialization of android_filesystem for the 'system' partition.
// Currently, the only difference is the inclusion of linker.config.pb file which specifies
// the provided and the required libraries to and from APEXes.
func SystemImageFactory() android.Module {
	module := &systemImage{}
	module.filesystemBuilder = module
	initFilesystemModule(module, &module.filesystem)
	return module
}

func (s systemImage) FsProps() FilesystemProperties {
	return s.filesystem.properties
}

func (s *systemImage) BuildLinkerConfigFile(ctx android.ModuleContext, builder *android.RuleBuilder, rebasedDir android.OutputPath) {
	if !proptools.Bool(s.filesystem.properties.Linker_config.Gen_linker_config) {
		return
	}

	provideModules, requireModules := s.getLibsForLinkerConfig(ctx)
	output := rebasedDir.Join(ctx, "etc", "linker.config.pb")
	linkerconfig.BuildLinkerConfig(ctx, builder, android.PathsForModuleSrc(ctx, s.filesystem.properties.Linker_config.Linker_config_srcs), provideModules, requireModules, output)

	s.appendToEntry(ctx, output)
}

// Filter the result of GatherPackagingSpecs to discard items targeting outside "system" / "root"
// partition.  Note that "apex" module installs its contents to "apex"(fake partition) as well
// for symbol lookup by imitating "activated" paths.
func (s *systemImage) FilterPackagingSpec(ps android.PackagingSpec) bool {
	return !ps.SkipInstall() &&
		(ps.Partition() == "system" || ps.Partition() == "root" ||
			strings.HasPrefix(ps.Partition(), "system/"))
}

func (s *systemImage) ModifyPackagingSpec(ps *android.PackagingSpec) {
	if strings.HasPrefix(ps.Partition(), "system/") {
		subPartition := strings.TrimPrefix(ps.Partition(), "system/")
		ps.SetPartition("system")
		ps.SetRelPathInPackage(filepath.Join(subPartition, ps.RelPathInPackage()))
	}
}