pkg/vminfo: refactor few things

Use default nop implementation for most openbsd/netbsd methods.
Move linux-specific vm type checks to linux code.
Remove indirection for CheckFiles as we have for RequiredFiles.

4 files changed, 24 insertions, 55 deletions

diff --git a/pkg/vminfo/linux.go b/pkg/vminfo/linux.go
index 0f598515c..52f6982b2 100644
--- a/pkg/vminfo/linux.go
+++ b/pkg/vminfo/linux.go
@@ -13,9 +13,13 @@ import (
 	"sort"
 	"strconv"
 	"strings"
+
+	"github.com/google/syzkaller/sys/targets"
 )
 
-type linux int
+type linux struct {
+	vmType string
+}
 
 func (linux) RequiredFiles() []string {
 	return []string{
@@ -27,7 +31,7 @@ func (linux) RequiredFiles() []string {
 	}
 }
 
-func (linux) checkFiles() []string {
+func (linux) CheckFiles() []string {
 	return []string{
 		"/proc/version",
 		"/proc/filesystems",
@@ -42,7 +46,10 @@ func (linux) machineInfos() []machineInfoFunc {
 	}
 }
 
-func (linux) parseModules(files filesystem) ([]*KernelModule, error) {
+func (linux linux) parseModules(files filesystem) ([]*KernelModule, error) {
+	if linux.vmType == targets.GVisor || linux.vmType == targets.Starnix {
+		return nil, nil
+	}
 	var modules []*KernelModule
 	re := regexp.MustCompile(`(\w+) ([0-9]+) .*(0[x|X][a-fA-F0-9]+)[^\n]*`)
 	modulesText, _ := files.ReadFile("/proc/modules")
diff --git a/pkg/vminfo/netbsd.go b/pkg/vminfo/netbsd.go
index e79e5a05f..13b666f91 100644
--- a/pkg/vminfo/netbsd.go
+++ b/pkg/vminfo/netbsd.go
@@ -7,22 +7,8 @@ import (
 	"github.com/google/syzkaller/prog"
 )
 
-type netbsd int
-
-func (netbsd) RequiredFiles() []string {
-	return nil
-}
-
-func (netbsd) checkFiles() []string {
-	return nil
-}
-
-func (netbsd) parseModules(files filesystem) ([]*KernelModule, error) {
-	return nil, nil
-}
-
-func (netbsd) machineInfos() []machineInfoFunc {
-	return nil
+type netbsd struct {
+	nopChecker
 }
 
 func (netbsd) syscallCheck(ctx *checkContext, call *prog.Syscall) string {
diff --git a/pkg/vminfo/openbsd.go b/pkg/vminfo/openbsd.go
index e7c0d78e2..fe7c0191e 100644
--- a/pkg/vminfo/openbsd.go
+++ b/pkg/vminfo/openbsd.go
@@ -7,22 +7,8 @@ import (
 	"github.com/google/syzkaller/prog"
 )
 
-type openbsd int
-
-func (openbsd) RequiredFiles() []string {
-	return nil
-}
-
-func (openbsd) checkFiles() []string {
-	return nil
-}
-
-func (openbsd) parseModules(files filesystem) ([]*KernelModule, error) {
-	return nil, nil
-}
-
-func (openbsd) machineInfos() []machineInfoFunc {
-	return nil
+type openbsd struct {
+	nopChecker
 }
 
 func (openbsd) syscallCheck(ctx *checkContext, call *prog.Syscall) string {
diff --git a/pkg/vminfo/vminfo.go b/pkg/vminfo/vminfo.go
index 89a35e2b2..d2a728585 100644
--- a/pkg/vminfo/vminfo.go
+++ b/pkg/vminfo/vminfo.go
@@ -37,7 +37,6 @@ type KernelModule struct {
 
 type Checker struct {
 	checker
-	vmType       string
 	source       queue.Source
 	checkContext *checkContext
 }
@@ -59,18 +58,17 @@ func New(ctx context.Context, cfg *Config) *Checker {
 	var impl checker
 	switch cfg.Target.OS {
 	case targets.Linux:
-		impl = new(linux)
+		impl = &linux{vmType: cfg.VMType}
 	case targets.NetBSD:
 		impl = new(netbsd)
 	case targets.OpenBSD:
 		impl = new(openbsd)
 	default:
-		impl = new(stub)
+		impl = new(nopChecker)
 	}
 	executor := queue.Plain()
 	return &Checker{
 		checker:      impl,
-		vmType:       cfg.VMType,
 		source:       queue.Deduplicate(ctx, executor),
 		checkContext: newCheckContext(ctx, cfg, impl, executor),
 	}
@@ -78,11 +76,7 @@ func New(ctx context.Context, cfg *Config) *Checker {
 
 func (checker *Checker) MachineInfo(fileInfos []*flatrpc.FileInfo) ([]*KernelModule, []byte, error) {
 	files := createVirtualFilesystem(fileInfos)
-	var modules []*KernelModule
-	var err error
-	if checker.vmType != targets.GVisor && checker.vmType != targets.Starnix {
-		modules, err = checker.parseModules(files)
-	}
+	modules, err := checker.parseModules(files)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -105,10 +99,6 @@ func (checker *Checker) MachineInfo(fileInfos []*flatrpc.FileInfo) ([]*KernelMod
 	return modules, info.Bytes(), nil
 }
 
-func (checker *Checker) CheckFiles() []string {
-	return checker.checkFiles()
-}
-
 func (checker *Checker) Run(files []*flatrpc.FileInfo, featureInfos []*flatrpc.FeatureInfo) (
 	map[*prog.Syscall]bool, map[*prog.Syscall]string, Features, error) {
 	ctx := checker.checkContext
@@ -128,7 +118,7 @@ type machineInfoFunc func(files filesystem, w io.Writer) (string, error)
 
 type checker interface {
 	RequiredFiles() []string
-	checkFiles() []string
+	CheckFiles() []string
 	parseModules(files filesystem) ([]*KernelModule, error)
 	machineInfos() []machineInfoFunc
 	syscallCheck(*checkContext, *prog.Syscall) string
@@ -179,24 +169,24 @@ func (files filesystem) ReadDir(dir string) []string {
 	return res
 }
 
-type stub int
+type nopChecker int
 
-func (stub) RequiredFiles() []string {
+func (nopChecker) RequiredFiles() []string {
 	return nil
 }
 
-func (stub) checkFiles() []string {
+func (nopChecker) CheckFiles() []string {
 	return nil
 }
 
-func (stub) parseModules(files filesystem) ([]*KernelModule, error) {
+func (nopChecker) parseModules(files filesystem) ([]*KernelModule, error) {
 	return nil, nil
 }
 
-func (stub) machineInfos() []machineInfoFunc {
+func (nopChecker) machineInfos() []machineInfoFunc {
 	return nil
 }
 
-func (stub) syscallCheck(*checkContext, *prog.Syscall) string {
+func (nopChecker) syscallCheck(*checkContext, *prog.Syscall) string {
 	return ""
 }