pkg/host: disable for akaros

akaros can't have own host version
because fuzzer does not run on akaros,
so just disable it all.

pkg/host/host.go

@@ -13,6 +13,13 @@ func DetectSupportedSyscalls(target *prog.Target, sandbox string) (
 	map[*prog.Syscall]bool, map[*prog.Syscall]string, error) {
 	supported := make(map[*prog.Syscall]bool)
 	unsupported := make(map[*prog.Syscall]string)
+	// Akaros does not have own host and parasitizes on some other OS.
+	if target.OS == "akaros" {
+		for _, c := range target.Syscalls {
+			supported[c] = true
+		}
+		return supported, unsupported, nil
+	}
 	for _, c := range target.Syscalls {
 		ok, reason := isSupported(c, sandbox)
 		if ok {
@@ -57,7 +64,7 @@ func unconditionallyEnabled() string { return "" }
 // Check detects features supported on the host.
 // Empty string for a feature means the feature is supported,
 // otherwise the string contains the reason why the feature is not supported.
-func Check() (*Features, error) {
+func Check(target *prog.Target) (*Features, error) {
 	const unsupported = "support is not implemented in syzkaller"
 	res := &Features{
 		FeatureCoverage:         {Name: "code coverage", Reason: unsupported},
@@ -68,6 +75,9 @@ func Check() (*Features, error) {
 		FeatureLeakChecking:     {Name: "leak checking", Reason: unsupported},
 		FeatureNetworkInjection: {Name: "net packed injection", Reason: unsupported},
 	}
+	if target.OS == "akaros" {
+		return res, nil
+	}
 	for n, check := range checkFeature {
 		if check == nil {
 			continue
@@ -84,7 +94,10 @@ func Check() (*Features, error) {
 
 // Setup enables and does any one-time setup for the requested features on the host.
 // Note: this can be called multiple times and must be idempotent.
-func Setup(features *Features) (func(), error) {
+func Setup(target *prog.Target, features *Features) (func(), error) {
+	if target.OS == "akaros" {
+		return nil, nil
+	}
 	var callback func()
 	for n, setup := range setupFeature {
 		if setup == nil || !features[n].Enabled {

pkg/host/host_test.go

@@ -48,7 +48,11 @@ func TestDetectSupportedSyscalls(t *testing.T) {
 
 func TestCheck(t *testing.T) {
 	t.Parallel()
-	features, err := Check()
+	target, err := prog.GetTarget(runtime.GOOS, runtime.GOARCH)
+	if err != nil {
+		t.Fatal(err)
+	}
+	features, err := Check(target)
 	if err != nil {
 		t.Fatal(err)
 	}

syz-fuzzer/fuzzer.go

@@ -196,7 +196,7 @@ func main() {
 	for _, feat := range r.CheckResult.Features {
 		log.Logf(0, "%v: %v", feat.Name, feat.Reason)
 	}
-	periodicCallback, err := host.Setup(r.CheckResult.Features)
+	periodicCallback, err := host.Setup(target, r.CheckResult.Features)
 	if err != nil {
 		log.Fatalf("BUG: %v", err)
 	}

syz-fuzzer/testing.go

@@ -60,7 +60,7 @@ func checkMachine(args *checkArgs) (*rpctype.CheckArgs, error) {
 	if err := checkRevisions(args); err != nil {
 		return nil, err
 	}
-	features, err := host.Check()
+	features, err := host.Check(args.target)
 	if err != nil {
 		return nil, err
 	}

tools/syz-execprog/execprog.go

@@ -54,11 +54,11 @@ func main() {
 		return
 	}
 
-	features, err := host.Check()
+	features, err := host.Check(target)
 	if err != nil {
 		log.Fatalf("%v", err)
 	}
-	if _, err = host.Setup(features); err != nil {
+	if _, err = host.Setup(target, features); err != nil {
 		log.Fatalf("%v", err)
 	}
 	config, execOpts := createConfig(target, entries, features)

tools/syz-stress/stress.go

@@ -48,11 +48,11 @@ func main() {
 		log.Fatalf("nothing to mutate (-generate=false and no corpus)")
 	}
 
-	features, err := host.Check()
+	features, err := host.Check(target)
 	if err != nil {
 		log.Fatalf("%v", err)
 	}
-	if _, err = host.Setup(features); err != nil {
+	if _, err = host.Setup(target, features); err != nil {
 		log.Fatalf("%v", err)
 	}