Specify bootconfig property in vendor_boot.img

bootconfig is a path to the text file, created based on
`INTERNAL_BOOTCONFIG` and `INTERNAL_BOOTCONFIG_FILE`. This is done by
auto generating a newly introduced bootconfig module. The
output file of the genrule module is passed as a property to the
vendor_boot.img module.

Test: Inspect the content of the generated vendor-bootconfig.img file
Test: Inspect the ninja command of the autogen vendor_boot.img
Bug: 379945468
Change-Id: I9c693de681e6dad7399f80df05825cce9b0c1c22
diff --git a/filesystem/bootconfig.go b/filesystem/bootconfig.go
new file mode 100644
index 0000000..b125824
--- /dev/null
+++ b/filesystem/bootconfig.go
@@ -0,0 +1,80 @@
+// Copyright 2024 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 filesystem
+
+import (
+	"android/soong/android"
+	"strings"
+
+	"github.com/google/blueprint/proptools"
+)
+
+func init() {
+	android.RegisterModuleType("bootconfig", BootconfigModuleFactory)
+	pctx.Import("android/soong/android")
+}
+
+type bootconfigProperty struct {
+	// List of bootconfig parameters that will be written as a line separated list in the output
+	// file.
+	Boot_config []string
+	// Path to the file that contains the list of bootconfig parameters. This will be appended
+	// to the output file, after the entries in boot_config.
+	Boot_config_file *string `android:"path"`
+}
+
+type BootconfigModule struct {
+	android.ModuleBase
+
+	properties bootconfigProperty
+}
+
+// bootconfig module generates the `vendor-bootconfig.img` file, which lists the bootconfig
+// parameters and can be passed as a `--vendor_bootconfig` value in mkbootimg invocation.
+func BootconfigModuleFactory() android.Module {
+	module := &BootconfigModule{}
+	module.AddProperties(&module.properties)
+	android.InitAndroidArchModule(module, android.DeviceSupported, android.MultilibCommon)
+	return module
+}
+
+func (m *BootconfigModule) GenerateAndroidBuildActions(ctx android.ModuleContext) {
+	bootConfig := m.properties.Boot_config
+	bootConfigFileStr := proptools.String(m.properties.Boot_config_file)
+	if len(bootConfig) == 0 && len(bootConfigFileStr) == 0 {
+		return
+	}
+
+	var bootConfigFile android.Path
+	if len(bootConfigFileStr) > 0 {
+		bootConfigFile = android.PathForModuleSrc(ctx, bootConfigFileStr)
+	}
+
+	outputPath := android.PathForModuleOut(ctx, ctx.ModuleName(), "vendor-bootconfig.img")
+	bootConfigOutput := android.PathForModuleOut(ctx, ctx.ModuleName(), "bootconfig.txt")
+	android.WriteFileRule(ctx, bootConfigOutput, strings.Join(bootConfig, "\n"))
+
+	bcFiles := android.Paths{bootConfigOutput}
+	if bootConfigFile != nil {
+		bcFiles = append(bcFiles, bootConfigFile)
+	}
+	ctx.Build(pctx, android.BuildParams{
+		Rule:        android.Cat,
+		Description: "concatenate bootconfig parameters",
+		Inputs:      bcFiles,
+		Output:      outputPath,
+	})
+	ctx.SetOutputFiles(android.Paths{outputPath}, "")
+}