Stop injecting symbols into host bionic binaries

The host bionic bootstrapping no longer needs an injected symbol.
Replace host_bionic_inject with host_bionic_verify that validates
the resulting binary, and add it as a validation dependency of the
binary.

Test: build and run host bionic binary
Change-Id: I3e303d2a164b6eef851bdc8075e6ee456c05b0a8

cc/binary.go

@@ -401,16 +401,18 @@ func (binary *binaryDecorator) link(ctx ModuleContext,
 		}
 	}
 
+	var validations android.WritablePaths
+
 	// Handle host bionic linker symbols.
 	if ctx.Os() == android.LinuxBionic && !binary.static() {
-		injectedOutputFile := outputFile
-		outputFile = android.PathForModuleOut(ctx, "prelinker", fileName)
+		verifyFile := android.PathForModuleOut(ctx, "host_bionic_verify.stamp")
 
 		if !deps.DynamicLinker.Valid() {
 			panic("Non-static host bionic modules must have a dynamic linker")
 		}
 
-		binary.injectHostBionicLinkerSymbols(ctx, outputFile, deps.DynamicLinker.Path(), injectedOutputFile)
+		binary.verifyHostBionicLinker(ctx, outputFile, deps.DynamicLinker.Path(), verifyFile)
+		validations = append(validations, verifyFile)
 	}
 
 	var sharedLibs android.Paths
@@ -430,7 +432,7 @@ func (binary *binaryDecorator) link(ctx ModuleContext,
 	// Register link action.
 	transformObjToDynamicBinary(ctx, objs.objFiles, sharedLibs, deps.StaticLibs,
 		deps.LateStaticLibs, deps.WholeStaticLibs, linkerDeps, deps.CrtBegin, deps.CrtEnd, true,
-		builderFlags, outputFile, nil)
+		builderFlags, outputFile, nil, validations)
 
 	objs.coverageFiles = append(objs.coverageFiles, deps.StaticLibObjs.coverageFiles...)
 	objs.coverageFiles = append(objs.coverageFiles, deps.WholeStaticLibObjs.coverageFiles...)
@@ -532,19 +534,19 @@ func (binary *binaryDecorator) hostToolPath() android.OptionalPath {
 }
 
 func init() {
-	pctx.HostBinToolVariable("hostBionicSymbolsInjectCmd", "host_bionic_inject")
+	pctx.HostBinToolVariable("verifyHostBionicCmd", "host_bionic_verify")
 }
 
-var injectHostBionicSymbols = pctx.AndroidStaticRule("injectHostBionicSymbols",
+var verifyHostBionic = pctx.AndroidStaticRule("verifyHostBionic",
 	blueprint.RuleParams{
-		Command:     "$hostBionicSymbolsInjectCmd -i $in -l $linker -o $out",
-		CommandDeps: []string{"$hostBionicSymbolsInjectCmd"},
+		Command:     "$verifyHostBionicCmd -i $in -l $linker && touch $out",
+		CommandDeps: []string{"$verifyHostBionicCmd"},
 	}, "linker")
 
-func (binary *binaryDecorator) injectHostBionicLinkerSymbols(ctx ModuleContext, in, linker android.Path, out android.WritablePath) {
+func (binary *binaryDecorator) verifyHostBionicLinker(ctx ModuleContext, in, linker android.Path, out android.WritablePath) {
 	ctx.Build(pctx, android.BuildParams{
-		Rule:        injectHostBionicSymbols,
-		Description: "inject host bionic symbols",
+		Rule:        verifyHostBionic,
+		Description: "verify host bionic",
 		Input:       in,
 		Implicit:    linker,
 		Output:      out,

cc/builder.go

@@ -731,7 +731,8 @@ func transformObjToStaticLib(ctx android.ModuleContext,
 // and shared libraries, to a shared library (.so) or dynamic executable
 func transformObjToDynamicBinary(ctx android.ModuleContext,
 	objFiles, sharedLibs, staticLibs, lateStaticLibs, wholeStaticLibs, deps android.Paths,
-	crtBegin, crtEnd android.OptionalPath, groupLate bool, flags builderFlags, outputFile android.WritablePath, implicitOutputs android.WritablePaths) {
+	crtBegin, crtEnd android.OptionalPath, groupLate bool, flags builderFlags,
+	outputFile android.WritablePath, implicitOutputs android.WritablePaths, validations android.WritablePaths) {
 
 	ldCmd := "${config.ClangBin}/clang++"
 
@@ -805,6 +806,7 @@ func transformObjToDynamicBinary(ctx android.ModuleContext,
 		Inputs:          objFiles,
 		Implicits:       deps,
 		OrderOnly:       sharedLibs,
+		Validations:     validations.Paths(),
 		Args:            args,
 	})
 }

cc/library.go

@@ -1343,7 +1343,7 @@ func (library *libraryDecorator) linkShared(ctx ModuleContext,
 	linkerDeps = append(linkerDeps, objs.tidyFiles...)
 	transformObjToDynamicBinary(ctx, objs.objFiles, sharedLibs,
 		deps.StaticLibs, deps.LateStaticLibs, deps.WholeStaticLibs,
-		linkerDeps, deps.CrtBegin, deps.CrtEnd, false, builderFlags, outputFile, implicitOutputs)
+		linkerDeps, deps.CrtBegin, deps.CrtEnd, false, builderFlags, outputFile, implicitOutputs, nil)
 
 	objs.coverageFiles = append(objs.coverageFiles, deps.StaticLibObjs.coverageFiles...)
 	objs.coverageFiles = append(objs.coverageFiles, deps.WholeStaticLibObjs.coverageFiles...)

cmd/host_bionic_verify/Android.bp

@@ -17,8 +17,7 @@ package {
 }
 
 blueprint_go_binary {
-    name: "host_bionic_inject",
-    deps: ["soong-symbol_inject"],
-    srcs: ["host_bionic_inject.go"],
-    testSrcs: ["host_bionic_inject_test.go"],
+    name: "host_bionic_verify",
+    srcs: ["host_bionic_verify.go"],
+    testSrcs: ["host_bionic_verify_test.go"],
 }

cmd/host_bionic_verify/host_bionic_verify.go

@@ -12,8 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// Verifies a host bionic executable with an embedded linker, then injects
-// the address of the _start function for the linker_wrapper to use.
+// Verifies a host bionic executable with an embedded linker.
 package main
 
 import (
@@ -22,19 +21,16 @@ import (
 	"fmt"
 	"io"
 	"os"
-
-	"android/soong/symbol_inject"
 )
 
 func main() {
-	var inputFile, linkerFile, outputFile string
+	var inputFile, linkerFile string
 
 	flag.StringVar(&inputFile, "i", "", "Input file")
 	flag.StringVar(&linkerFile, "l", "", "Linker file")
-	flag.StringVar(&outputFile, "o", "", "Output file")
 	flag.Parse()
 
-	if inputFile == "" || linkerFile == "" || outputFile == "" || flag.NArg() != 0 {
+	if inputFile == "" || linkerFile == "" || flag.NArg() != 0 {
 		flag.Usage()
 		os.Exit(1)
 	}
@@ -46,75 +42,52 @@ func main() {
 	}
 	defer r.Close()
 
-	file, err := symbol_inject.OpenFile(r)
-	if err != nil {
-		fmt.Fprintln(os.Stderr, err.Error())
-		os.Exit(3)
-	}
-
 	linker, err := elf.Open(linkerFile)
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err.Error())
 		os.Exit(4)
 	}
 
-	startAddr, err := parseElf(r, linker)
+	err = checkElf(r, linker)
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err.Error())
 		os.Exit(5)
 	}
-
-	w, err := os.OpenFile(outputFile, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0777)
-	if err != nil {
-		fmt.Fprintln(os.Stderr, err.Error())
-		os.Exit(6)
-	}
-	defer w.Close()
-
-	err = symbol_inject.InjectUint64Symbol(file, w, "__dlwrap_original_start", startAddr)
-	if err != nil {
-		fmt.Fprintln(os.Stderr, err.Error())
-		os.Exit(7)
-	}
 }
 
 // Check the ELF file, and return the address to the _start function
-func parseElf(r io.ReaderAt, linker *elf.File) (uint64, error) {
+func checkElf(r io.ReaderAt, linker *elf.File) error {
 	file, err := elf.NewFile(r)
 	if err != nil {
-		return 0, err
+		return err
 	}
 
 	symbols, err := file.Symbols()
 	if err != nil {
-		return 0, err
+		return err
 	}
 
 	for _, prog := range file.Progs {
 		if prog.Type == elf.PT_INTERP {
-			return 0, fmt.Errorf("File should not have a PT_INTERP header")
+			return fmt.Errorf("File should not have a PT_INTERP header")
 		}
 	}
 
 	if dlwrap_start, err := findSymbol(symbols, "__dlwrap__start"); err != nil {
-		return 0, err
+		return err
 	} else if dlwrap_start.Value != file.Entry {
-		return 0, fmt.Errorf("Expected file entry(0x%x) to point to __dlwrap_start(0x%x)",
+		return fmt.Errorf("Expected file entry(0x%x) to point to __dlwrap_start(0x%x)",
 			file.Entry, dlwrap_start.Value)
 	}
 
 	err = checkLinker(file, linker, symbols)
 	if err != nil {
-		return 0, fmt.Errorf("Linker executable failed verification against app embedded linker: %s\n"+
+		return fmt.Errorf("Linker executable failed verification against app embedded linker: %s\n"+
 			"linker might not be in sync with crtbegin_dynamic.o.",
 			err)
 	}
 
-	start, err := findSymbol(symbols, "_start")
-	if err != nil {
-		return 0, fmt.Errorf("Failed to find _start symbol")
-	}
-	return start.Value, nil
+	return nil
 }
 
 func findSymbol(symbols []elf.Symbol, name string) (elf.Symbol, error) {