Build vbmeta partitions with soong

AVB is Android Verified Boot:
https://source.android.com/docs/security/features/verifiedboot
It works by signing all the partitions, but then also including an extra
metadata paritition called vbmeta that depends on all the other
signed partitions. This creates a requirement that you update all those
partitions and the vbmeta partition together, so in order to relax that
requirement products can set up "chained" vbmeta partitions, where a
chained partition like vbmeta_system might contain the avb metadata for
just a few products. In cuttlefish vbmeta_system contains metadata about
product, system, and system_ext. Using chained partitions, that group of
partitions can be updated independently from the other signed
partitions.

Bug: 377563298
Test: m nothing (the diff test currently fails, but this is a start)
Change-Id: I397af3a418bd23bcbf8f620c436afcacf69974fd

1 files changed, 12 insertions, 16 deletions

diff --git a/filesystem/vbmeta.go b/filesystem/vbmeta.go
index 0bae479cf..6a3fc1f18 100644
--- a/filesystem/vbmeta.go
+++ b/filesystem/vbmeta.go
@@ -25,19 +25,19 @@ import (
 )
 
 func init() {
-	android.RegisterModuleType("vbmeta", vbmetaFactory)
+	android.RegisterModuleType("vbmeta", VbmetaFactory)
 }
 
 type vbmeta struct {
 	android.ModuleBase
 
-	properties vbmetaProperties
+	properties VbmetaProperties
 
 	output     android.OutputPath
 	installDir android.InstallPath
 }
 
-type vbmetaProperties struct {
+type VbmetaProperties struct {
 	// Name of the partition stored in vbmeta desc. Defaults to the name of this module.
 	Partition_name *string
 
@@ -50,9 +50,8 @@ type vbmetaProperties struct {
 	// Algorithm that avbtool will use to sign this vbmeta image. Default is SHA256_RSA4096.
 	Algorithm *string
 
-	// File whose content will provide the rollback index. If unspecified, the rollback index
-	// is from PLATFORM_SECURITY_PATCH
-	Rollback_index_file *string `android:"path"`
+	// The rollback index. If unspecified, the rollback index is from PLATFORM_SECURITY_PATCH
+	Rollback_index *int64
 
 	// Rollback index location of this vbmeta image. Must be 0, 1, 2, etc. Default is 0.
 	Rollback_index_location *int64
@@ -62,7 +61,7 @@ type vbmetaProperties struct {
 	Partitions proptools.Configurable[[]string]
 
 	// List of chained partitions that this vbmeta deletages the verification.
-	Chained_partitions []chainedPartitionProperties
+	Chained_partitions []ChainedPartitionProperties
 
 	// List of key-value pair of avb properties
 	Avb_properties []avbProperty
@@ -76,7 +75,7 @@ type avbProperty struct {
 	Value *string
 }
 
-type chainedPartitionProperties struct {
+type ChainedPartitionProperties struct {
 	// Name of the chained partition
 	Name *string
 
@@ -95,7 +94,7 @@ type chainedPartitionProperties struct {
 }
 
 // vbmeta is the partition image that has the verification information for other partitions.
-func vbmetaFactory() android.Module {
+func VbmetaFactory() android.Module {
 	module := &vbmeta{}
 	module.AddProperties(&module.properties)
 	android.InitAndroidArchModule(module, android.DeviceSupported, android.MultilibCommon)
@@ -217,15 +216,12 @@ func (v *vbmeta) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 
 // Returns the embedded shell command that prints the rollback index
 func (v *vbmeta) rollbackIndexCommand(ctx android.ModuleContext) string {
-	var cmd string
-	if v.properties.Rollback_index_file != nil {
-		f := android.PathForModuleSrc(ctx, proptools.String(v.properties.Rollback_index_file))
-		cmd = "cat " + f.String()
+	if v.properties.Rollback_index != nil {
+		return fmt.Sprintf("%d", *v.properties.Rollback_index)
 	} else {
-		cmd = "date -d 'TZ=\"GMT\" " + ctx.Config().PlatformSecurityPatch() + "' +%s"
+		// Take the first line and remove the newline char
+		return "$(date -d 'TZ=\"GMT\" " + ctx.Config().PlatformSecurityPatch() + "' +%s | head -1 | tr -d '\n'" + ")"
 	}
-	// Take the first line and remove the newline char
-	return "$(" + cmd + " | head -1 | tr -d '\n'" + ")"
 }
 
 // Extract public keys from chained_partitions.private_key. The keys are indexed with the partition