tools/syz-kconf: add tool

syz-kconf generates all Linux kernel configs.

Update #2171

1 files changed, 283 insertions, 0 deletions

diff --git a/tools/syz-kconf/parser.go b/tools/syz-kconf/parser.go
new file mode 100644
index 000000000..dad090b8a
--- /dev/null
+++ b/tools/syz-kconf/parser.go
@@ -0,0 +1,283 @@
+// Copyright 2020 syzkaller project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"path/filepath"
+
+	"github.com/google/syzkaller/pkg/kconfig"
+	"github.com/google/syzkaller/pkg/vcs"
+	"gopkg.in/yaml.v3"
+)
+
+type Instance struct {
+	Name      string
+	Kernel    Kernel
+	Verbatim  []byte
+	Shell     []Shell
+	Features  Features
+	ConfigMap map[string]*Config
+	Configs   []*Config
+}
+
+type Config struct {
+	Name        string
+	Value       string
+	Override    bool
+	Optional    bool
+	Constraints []string
+	File        string
+	Line        int
+}
+
+type Kernel struct {
+	Repo string
+	Tag  string
+}
+
+type Shell struct {
+	Cmd         string
+	Constraints []string
+}
+
+type Features map[string]bool
+
+func (features Features) Match(constraints []string) bool {
+	for _, feat := range constraints {
+		switch feat {
+		case featOptional, featOverride, featWeak:
+			continue
+		}
+		if feat[0] == '-' {
+			if features[feat[1:]] {
+				return false
+			}
+		} else if !features[feat] {
+			return false
+		}
+	}
+	return true
+}
+
+type rawMain struct {
+	Instances []map[string][]string
+	Includes  []map[string][]string
+}
+
+type rawFile struct {
+	Kernel struct {
+		Repo string
+		Tag  string
+	}
+	Shell    []yaml.Node
+	Verbatim string
+	Config   []yaml.Node
+}
+
+func parseMainSpec(file string) ([]*Instance, error) {
+	data, err := ioutil.ReadFile(file)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read config file: %v", err)
+	}
+	dec := yaml.NewDecoder(bytes.NewReader(data))
+	dec.KnownFields(true)
+	raw := new(rawMain)
+	if err := dec.Decode(raw); err != nil {
+		return nil, fmt.Errorf("failed to parse %v: %v", file, err)
+	}
+	var instances []*Instance
+	for _, inst := range raw.Instances {
+		for name, features := range inst {
+			inst, err := parseInstance(name, filepath.Dir(file), features, raw.Includes)
+			if err != nil {
+				return nil, err
+			}
+			instances = append(instances, inst)
+			inst, err = parseInstance(name+"-base", filepath.Dir(file), append(features, featBaseline), raw.Includes)
+			if err != nil {
+				return nil, err
+			}
+			instances = append(instances, inst)
+		}
+	}
+	return instances, nil
+}
+
+func parseInstance(name, configDir string, features []string, includes []map[string][]string) (*Instance, error) {
+	inst := &Instance{
+		Name:      name,
+		Features:  make(Features),
+		ConfigMap: make(map[string]*Config),
+	}
+	for _, feat := range features {
+		inst.Features[feat] = true
+	}
+	errs := new(Errors)
+	for _, include := range includes {
+		for file, features := range include {
+			if !inst.Features.Match(features) {
+				continue
+			}
+			raw, err := parseFile(filepath.Join(configDir, "bits", file))
+			if err != nil {
+				return nil, err
+			}
+			mergeFile(inst, raw, file, errs)
+		}
+	}
+	inst.Verbatim = bytes.TrimSpace(inst.Verbatim)
+	return inst, errs.err()
+}
+
+func parseFile(file string) (*rawFile, error) {
+	data, err := ioutil.ReadFile(file)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read %v: %v", file, err)
+	}
+	dec := yaml.NewDecoder(bytes.NewReader(data))
+	dec.KnownFields(true)
+	raw := new(rawFile)
+	if err := dec.Decode(raw); err != nil {
+		return nil, fmt.Errorf("failed to parse %v: %v", file, err)
+	}
+	return raw, nil
+}
+
+func mergeFile(inst *Instance, raw *rawFile, file string, errs *Errors) {
+	if raw.Kernel.Repo != "" || raw.Kernel.Tag != "" {
+		if !vcs.CheckRepoAddress(raw.Kernel.Repo) {
+			errs.push("%v: bad kernel repo %q", file, raw.Kernel.Repo)
+		}
+		if !vcs.CheckBranch(raw.Kernel.Tag) {
+			errs.push("%v: bad kernel tag %q", file, raw.Kernel.Tag)
+		}
+		if inst.Kernel.Repo != "" {
+			errs.push("%v: kernel is set twice", file)
+		}
+		inst.Kernel = raw.Kernel
+	}
+	for _, node := range raw.Shell {
+		cmd, _, constraints, err := parseNode(node)
+		if err != nil {
+			errs.push("%v:%v: %v", file, node.Line, err)
+		}
+		inst.Shell = append(inst.Shell, Shell{
+			Cmd:         cmd,
+			Constraints: constraints,
+		})
+	}
+	inst.Verbatim = append(append(inst.Verbatim, raw.Verbatim...), '\n')
+	for _, node := range raw.Config {
+		mergeConfig(inst, file, node, errs)
+	}
+}
+
+func mergeConfig(inst *Instance, file string, node yaml.Node, errs *Errors) {
+	name, val, constraints, err := parseNode(node)
+	if err != nil {
+		errs.push("%v:%v: %v", file, node.Line, err)
+		return
+	}
+	cfg := &Config{
+		Name:  name,
+		Value: val,
+		File:  file,
+		Line:  node.Line,
+	}
+	for _, feat := range constraints {
+		switch feat {
+		case featOverride:
+			cfg.Override = true
+		case featOptional:
+			cfg.Optional = true
+		case featWeak:
+			cfg.Override, cfg.Optional = true, true
+		default:
+			cfg.Constraints = append(cfg.Constraints, feat)
+		}
+	}
+	if prev := inst.ConfigMap[name]; prev != nil {
+		if !cfg.Override {
+			errs.push("%v:%v: %v is already defined at %v:%v", file, node.Line, name, prev.File, prev.Line)
+		}
+		*prev = *cfg
+		return
+	}
+	if cfg.Override && !cfg.Optional {
+		errs.push("%v:%v: %v nothing to override", file, node.Line, name)
+	}
+	inst.ConfigMap[name] = cfg
+	inst.Configs = append(inst.Configs, cfg)
+}
+
+func parseNode(node yaml.Node) (name, val string, constraints []string, err error) {
+	// Simplest case: - FOO.
+	val = kconfig.Yes
+	if node.Decode(&name) == nil {
+		return
+	}
+	complexVal := make(map[string]yaml.Node)
+	if err = node.Decode(complexVal); err != nil {
+		return
+	}
+	var valNode yaml.Node
+	for k, v := range complexVal {
+		name, valNode = k, v
+		break
+	}
+	// Case: - FOO: 42.
+	if intVal := 0; valNode.Decode(&intVal) == nil {
+		val = fmt.Sprint(intVal)
+		return
+	}
+	if valNode.Decode(&val) == nil {
+		// Case: - FOO: "string".
+		if valNode.Style == yaml.DoubleQuotedStyle {
+			val = `"` + val + `"`
+			return
+		}
+		// Case: - FOO: n.
+		if valNode.Style == 0 && val == "n" {
+			val = kconfig.No
+			return
+		}
+		err = fmt.Errorf("bad config format")
+		return
+	}
+	// Case: - FOO: [...].
+	propsNode := []yaml.Node{}
+	if err = valNode.Decode(&propsNode); err != nil {
+		return
+	}
+	for _, propNode := range propsNode {
+		prop := ""
+		if err = propNode.Decode(&prop); err != nil {
+			return
+		}
+		if propNode.Style == yaml.DoubleQuotedStyle {
+			val = `"` + prop + `"`
+		} else if prop == "n" {
+			val = kconfig.No
+		} else {
+			constraints = append(constraints, prop)
+		}
+	}
+	return
+}
+
+type Errors []byte
+
+func (errs *Errors) push(msg string, args ...interface{}) {
+	*errs = append(*errs, fmt.Sprintf(msg+"\n", args...)...)
+}
+
+func (errs *Errors) err() error {
+	if len(*errs) == 0 {
+		return nil
+	}
+	return fmt.Errorf("%s", *errs)
+}