pkg/subsystem: export debug info

Make it possible to print more debugging information when (re)generating
a subsystem list.

Include parent inference details to the source code itself and add a
-debug flag to list the source files assigned to each subsystem.

2 files changed, 42 insertions, 8 deletions

diff --git a/tools/syz-query-subsystems/generator.go b/tools/syz-query-subsystems/generator.go
index a7db17d3f..3e2251747 100644
--- a/tools/syz-query-subsystems/generator.go
+++ b/tools/syz-query-subsystems/generator.go
@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"go/format"
 	"regexp"
+	"slices"
 	"sort"
 	"strings"
 	"text/template"
@@ -18,7 +19,8 @@ import (
 	"github.com/google/syzkaller/pkg/vcs"
 )
 
-func generateSubsystemsFile(name string, list []*subsystem.Subsystem, commit *vcs.Commit) ([]byte, error) {
+func generateSubsystemsFile(name string, list []*subsystem.Subsystem, commit *vcs.Commit,
+	debugInfo *subsystem.DebugInfo) ([]byte, error) {
 	// Set names first -- we'll need them for filling in the Parents array.
 	objToName := map[*subsystem.Subsystem]string{}
 	for _, entry := range list {
@@ -41,11 +43,16 @@ func generateSubsystemsFile(name string, list []*subsystem.Subsystem, commit *vc
 		// The serializer does not understand parent references and just prints all the
 		// nested structures.
 		// Therefore we call it separately for the fields it can understand.
-		parents := []string{}
+		parents := []parentInfo{}
 		for _, p := range entry.Parents {
-			parents = append(parents, objToName[p])
+			parents = append(parents, parentInfo{
+				Name:    objToName[p],
+				Comment: debugInfo.ParentChildComment[p][entry],
+			})
 		}
-		sort.Strings(parents)
+		slices.SortFunc(parents, func(a, b parentInfo) int {
+			return strings.Compare(a.Name, b.Name)
+		})
 		subsystem := &templateSubsystem{
 			VarName:      varName,
 			Name:         serializer.WriteString(entry.Name),
@@ -121,11 +128,16 @@ type templateSubsystem struct {
 	PathRules    string
 	Lists        string
 	Maintainers  string
-	Parents      []string
+	Parents      []parentInfo
 	NoReminders  bool
 	NoIndirectCc bool
 }
 
+type parentInfo struct {
+	Name    string
+	Comment string
+}
+
 type templateVars struct {
 	Name       string
 	Version    int
@@ -171,7 +183,14 @@ var {{range $i, $item := .List}}
  Maintainers: {{.Maintainers}},
 {{- end}}
 {{- if .Parents}}
- Parents: []*Subsystem{ {{range .Parents}} &{{.}}, {{end}} },
+ Parents: []*Subsystem{
+ {{- range .Parents}}
+  {{- if .Comment}}
+   // {{.Comment}}
+  {{- end}}
+   &{{.Name}},
+ {{end -}}
+},
 {{- end}}
  PathRules: {{.PathRules}},
 {{- if .NoReminders}}
diff --git a/tools/syz-query-subsystems/query_subsystems.go b/tools/syz-query-subsystems/query_subsystems.go
index 8f0fbae76..74da8ee8d 100644
--- a/tools/syz-query-subsystems/query_subsystems.go
+++ b/tools/syz-query-subsystems/query_subsystems.go
@@ -28,6 +28,7 @@ var (
 	flagName          = flag.String("name", "", "the name under which the list should be saved")
 	flagFilter        = flag.String("filter", "", "comma-separated list of subsystems to keep")
 	flagEmails        = flag.Bool("emails", true, "save lists and maintainer fields")
+	flagDebug         = flag.Bool("debug", false, "print the debugging information")
 )
 
 var nameRe = regexp.MustCompile(`^[a-z]\w*$`)
@@ -48,10 +49,11 @@ func main() {
 		tool.Failf("the name is not acceptable")
 	}
 	// Query the subsystems.
-	list, err := linux.ListFromRepo(*flagKernelRepo)
+	list, debugInfo, err := linux.ListFromRepo(*flagKernelRepo)
 	if err != nil {
 		tool.Failf("failed to query subsystems: %v", err)
 	}
+	printDebugInfo(debugInfo)
 	list = postProcessList(list)
 	// Save the list.
 	folder := filepath.Join(*flagSyzkallerRepo, "pkg", "subsystem", "lists")
@@ -62,7 +64,7 @@ func main() {
 	if err != nil {
 		tool.Failf("failed to fetch commit info: %v", err)
 	}
-	code, err := generateSubsystemsFile(*flagName, list, commitInfo)
+	code, err := generateSubsystemsFile(*flagName, list, commitInfo, debugInfo)
 	if err != nil {
 		tool.Failf("failed to generate code: %s", err)
 	}
@@ -72,6 +74,19 @@ func main() {
 	}
 }
 
+func printDebugInfo(info *subsystem.DebugInfo) {
+	if !*flagDebug {
+		return
+	}
+	for item, list := range info.FileLists {
+		fmt.Printf("****\n")
+		fmt.Printf("Subsystem %q (%d paths)\n", item.Name, len(list))
+		for _, path := range list {
+			fmt.Printf("%s\n", path)
+		}
+	}
+}
+
 func postProcessList(list []*subsystem.Subsystem) []*subsystem.Subsystem {
 	if *flagFilter != "" {
 		list = subsystem.FilterList(list, prepareFilter())