Rename non-stubs variant of a lib if it is included in APEX

If a lib is directly included in an APEX (via native_shared_libs
property) and the lib has stubs (via stubs.versions property), then the
ordinary non-stubs variant of the library is renamed to
<libname>.bootstrap in the makefile. At the same time, the stubs variant
of the lib becomes visible and it's name is <libname>.

This ensures that modules in Android.mk build against the stubs
variant thus preventing them from using private APIs in the lib.

The non-stubs variant, however, is used if the module explicitly has
set the new 'bootstrap' property to true. This is useful for building
some early binaries (such as init and vold) which need to run before
APEXes are activated. Since they can't use the bionic libs from the
runtime APEX, they should use the bionic libs left in the system
partition which is called the boostrap bionic.

Bug: 120266448
Test: m
Test: m with https://android-review.googlesource.com/c/platform/bionic/+/849044

Change-Id: I882b8aeb5b29460f07b4424e4f8eb844d6c9a9b0

apex/apex.go

@@ -492,6 +492,19 @@ func getCopyManifestForNativeLibrary(cc *cc.Module) (fileToCopy android.Path, di
 	if !cc.Arch().Native {
 		dirInApex = filepath.Join(dirInApex, cc.Arch().ArchType.String())
 	}
+	switch cc.Name() {
+	case "libc", "libm", "libdl":
+		// Special case for bionic libs. This is to prevent the bionic libs
+		// from being included in the search path /apex/com.android.apex/lib.
+		// This exclusion is required because bionic libs in the runtime APEX
+		// are available via the legacy paths /system/lib/libc.so, etc. By the
+		// init process, the bionic libs in the APEX are bind-mounted to the
+		// legacy paths and thus will be loaded into the default linker namespace.
+		// If the bionic libs are directly in /apex/com.android.apex/lib then
+		// the same libs will be again loaded to the runtime linker namespace,
+		// which will result double loading of bionic libs that isn't supported.
+		dirInApex = filepath.Join(dirInApex, "bionic")
+	}
 
 	fileToCopy = cc.OutputFile().Path()
 	return

apex/apex_test.go

@@ -492,6 +492,13 @@ func TestApexWithSystemLibsStubs(t *testing.T) {
 				versions: ["27", "28", "29"],
 			},
 		}
+
+		cc_library {
+			name: "libBootstrap",
+			srcs: ["mylib.cpp"],
+			stl: "none",
+			bootstrap: true,
+		}
 	`)
 
 	apexRule := ctx.ModuleForTests("myapex", "android_common_myapex").Rule("apexRule")
@@ -499,11 +506,11 @@ func TestApexWithSystemLibsStubs(t *testing.T) {
 
 	// Ensure that mylib, libm, libdl are included.
 	ensureContains(t, copyCmds, "image.apex/lib64/mylib.so")
-	ensureContains(t, copyCmds, "image.apex/lib64/libm.so")
-	ensureContains(t, copyCmds, "image.apex/lib64/libdl.so")
+	ensureContains(t, copyCmds, "image.apex/lib64/bionic/libm.so")
+	ensureContains(t, copyCmds, "image.apex/lib64/bionic/libdl.so")
 
 	// Ensure that libc is not included (since it has stubs and not listed in native_shared_libs)
-	ensureNotContains(t, copyCmds, "image.apex/lib64/libc.so")
+	ensureNotContains(t, copyCmds, "image.apex/lib64/bionic/libc.so")
 
 	mylibLdFlags := ctx.ModuleForTests("mylib", "android_arm64_armv8-a_core_shared_myapex").Rule("ld").Args["libFlags"]
 	mylibCFlags := ctx.ModuleForTests("mylib", "android_arm64_armv8-a_core_static_myapex").Rule("cc").Args["cFlags"]
@@ -538,6 +545,12 @@ func TestApexWithSystemLibsStubs(t *testing.T) {
 	// ... Cflags from stub is correctly exported to mylib
 	ensureContains(t, mylibCFlags, "__LIBDL_API__=27")
 	ensureContains(t, mylibSharedCFlags, "__LIBDL_API__=27")
+
+	// Ensure that libBootstrap is depending on the platform variant of bionic libs
+	libFlags := ctx.ModuleForTests("libBootstrap", "android_arm64_armv8-a_core_shared").Rule("ld").Args["libFlags"]
+	ensureContains(t, libFlags, "libc/android_arm64_armv8-a_core_shared/libc.so")
+	ensureContains(t, libFlags, "libm/android_arm64_armv8-a_core_shared/libm.so")
+	ensureContains(t, libFlags, "libdl/android_arm64_armv8-a_core_shared/libdl.so")
 }
 
 func TestFilesInSubDir(t *testing.T) {

cc/androidmk.go

@@ -29,9 +29,12 @@ var (
 )
 
 type AndroidMkContext interface {
+	Name() string
 	Target() android.Target
 	subAndroidMk(*android.AndroidMkData, interface{})
 	useVndk() bool
+	static() bool
+	inRecovery() bool
 }
 
 type subAndroidMkProvider interface {
@@ -59,7 +62,11 @@ func (c *Module) AndroidMk() android.AndroidMkData {
 
 	ret := android.AndroidMkData{
 		OutputFile: c.outputFile,
-		Required:   append(c.Properties.AndroidMkRuntimeLibs, c.Properties.ApexesProvidingSharedLibs...),
+		// TODO(jiyong): add the APEXes providing shared libs to the required modules
+		// Currently, adding c.Properties.ApexesProvidingSharedLibs is causing multiple
+		// runtime APEXes (com.android.runtime.debug|release) to be installed. And this
+		// is breaking some older devices (like marlin) where system.img is small.
+		Required: c.Properties.AndroidMkRuntimeLibs,
 		Include:  "$(BUILD_SYSTEM)/soong_cc_prebuilt.mk",
 
 		Extra: []android.AndroidMkExtraFunc{
@@ -172,13 +179,23 @@ func (library *libraryDecorator) AndroidMk(ctx AndroidMkContext, ret *android.An
 		}
 	})
 
-	if library.shared() {
+	if library.shared() && !library.buildStubs() {
 		ctx.subAndroidMk(ret, library.baseInstaller)
 	} else {
 		ret.Extra = append(ret.Extra, func(w io.Writer, outputFile android.Path) {
 			fmt.Fprintln(w, "LOCAL_UNINSTALLABLE_MODULE := true")
+			if library.buildStubs() {
+				fmt.Fprintln(w, "LOCAL_NO_NOTICE_FILE := true")
+			}
 		})
 	}
+
+	if len(library.Properties.Stubs.Versions) > 0 && android.DirectlyInAnyApex(ctx.Name()) &&
+		!ctx.inRecovery() && !ctx.useVndk() && !ctx.static() {
+		if !library.buildStubs() {
+			ret.SubName = ".bootstrap"
+		}
+	}
 }
 
 func (object *objectLinker) AndroidMk(ctx AndroidMkContext, ret *android.AndroidMkData) {

cc/cc.go

@@ -201,6 +201,10 @@ type BaseProperties struct {
 	Recovery_available *bool
 
 	InRecovery bool `blueprint:"mutated"`
+
+	// Allows this module to use non-APEX version of libraries. Useful
+	// for building binaries that are started before APEXes are activated.
+	Bootstrap *bool
 }
 
 type VendorProperties struct {
@@ -250,6 +254,8 @@ type ModuleContextIntf interface {
 	isPgoCompile() bool
 	useClangLld(actx ModuleContext) bool
 	isApex() bool
+	hasStubsVariants() bool
+	isStubs() bool
 }
 
 type ModuleContext interface {
@@ -676,6 +682,14 @@ func (ctx *moduleContextImpl) isApex() bool {
 	return ctx.mod.ApexName() != ""
 }
 
+func (ctx *moduleContextImpl) hasStubsVariants() bool {
+	return ctx.mod.HasStubsVariants()
+}
+
+func (ctx *moduleContextImpl) isStubs() bool {
+	return ctx.mod.IsStubs()
+}
+
 func newBaseModule(hod android.HostOrDeviceSupported, multilib android.Multilib) *Module {
 	return &Module{
 		hod:      hod,
@@ -855,6 +869,18 @@ func (c *Module) GenerateAndroidBuildActions(actx android.ModuleContext) {
 			return
 		}
 		c.outputFile = android.OptionalPathForPath(outputFile)
+
+		// If a lib is directly included in any of the APEXes, unhide the stubs
+		// variant having the latest version gets visible to make. In addition,
+		// the non-stubs variant is renamed to <libname>.bootstrap. This is to
+		// force anything in the make world to link against the stubs library.
+		// (unless it is explicitly referenced via .bootstrap suffix or the
+		// module is marked with 'bootstrap: true').
+		if c.HasStubsVariants() && android.DirectlyInAnyApex(ctx.baseModuleName()) &&
+			!c.inRecovery() && !c.useVndk() && !c.static() && c.IsStubs() {
+			c.Properties.HideFromMake = false // unhide
+			// Note: this is still non-installable
+		}
 	}
 
 	if c.installer != nil && !c.Properties.PreventInstall && c.IsForPlatform() && c.outputFile.Valid() {
@@ -1446,8 +1472,8 @@ func (c *Module) depsToPaths(ctx android.ModuleContext) PathDeps {
 					// If not building for APEX, use stubs only when it is from
 					// an APEX (and not from platform)
 					useThisDep = (depInPlatform != depIsStubs)
-					if c.inRecovery() {
-						// However, for recovery modules, since there is no APEX there,
+					if c.inRecovery() || Bool(c.Properties.Bootstrap) {
+						// However, for recovery or bootstrap modules,
 						// always link to non-stub variant
 						useThisDep = !depIsStubs
 					}