bpf: support installing to vendor

Bug: 140330870
Test: use bpf{} to install bpf program to vendor and have it
  successfully loaded and installed by Android's bpfloader.

Change-Id: If0aac3098e39498f0238516ec839b6ac910cc61e
diff --git a/bpf/bpf.go b/bpf/bpf.go
index a4999e5..14b2d84 100644
--- a/bpf/bpf.go
+++ b/bpf/bpf.go
@@ -20,7 +20,6 @@
 	"strings"
 
 	"android/soong/android"
-	_ "android/soong/cc/config"
 
 	"github.com/google/blueprint"
 	"github.com/google/blueprint/proptools"
@@ -74,7 +73,10 @@
 	Include_dirs []string
 	Sub_dir      string
 	// If set to true, generate BTF debug info for maps & programs
-	Btf          *bool
+	Btf    *bool
+	Vendor *bool
+
+	VendorInternal bool `blueprint:"mutated"`
 }
 
 type bpf struct {
@@ -85,6 +87,41 @@
 	objs android.Paths
 }
 
+var _ android.ImageInterface = (*bpf)(nil)
+
+func (bpf *bpf) ImageMutatorBegin(ctx android.BaseModuleContext) {}
+
+func (bpf *bpf) CoreVariantNeeded(ctx android.BaseModuleContext) bool {
+	return !proptools.Bool(bpf.properties.Vendor)
+}
+
+func (bpf *bpf) RamdiskVariantNeeded(ctx android.BaseModuleContext) bool {
+	return false
+}
+
+func (bpf *bpf) VendorRamdiskVariantNeeded(ctx android.BaseModuleContext) bool {
+	return false
+}
+
+func (bpf *bpf) DebugRamdiskVariantNeeded(ctx android.BaseModuleContext) bool {
+	return false
+}
+
+func (bpf *bpf) RecoveryVariantNeeded(ctx android.BaseModuleContext) bool {
+	return false
+}
+
+func (bpf *bpf) ExtraImageVariations(ctx android.BaseModuleContext) []string {
+	if proptools.Bool(bpf.properties.Vendor) {
+		return []string{"vendor"}
+	}
+	return nil
+}
+
+func (bpf *bpf) SetImageVariation(ctx android.BaseModuleContext, variation string, module android.Module) {
+	bpf.properties.VendorInternal = variation == "vendor"
+}
+
 func (bpf *bpf) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	cflags := []string{
 		"-nostdlibinc",
@@ -132,8 +169,8 @@
 		if proptools.Bool(bpf.properties.Btf) {
 			objStripped := android.ObjPathWithExt(ctx, "", src, "o")
 			ctx.Build(pctx, android.BuildParams{
-				Rule: stripRule,
-				Input: obj,
+				Rule:   stripRule,
+				Input:  obj,
 				Output: objStripped,
 				Args: map[string]string{
 					"stripCmd": "${config.ClangBin}/llvm-strip",
@@ -154,7 +191,12 @@
 			fmt.Fprintln(w)
 			fmt.Fprintln(w, "LOCAL_PATH :=", moduleDir)
 			fmt.Fprintln(w)
-			localModulePath := "LOCAL_MODULE_PATH := $(TARGET_OUT_ETC)/bpf"
+			var localModulePath string
+			if bpf.properties.VendorInternal {
+				localModulePath = "LOCAL_MODULE_PATH := $(TARGET_OUT_VENDOR_ETC)/bpf"
+			} else {
+				localModulePath = "LOCAL_MODULE_PATH := $(TARGET_OUT_ETC)/bpf"
+			}
 			if len(bpf.properties.Sub_dir) > 0 {
 				localModulePath += "/" + bpf.properties.Sub_dir
 			}