pkg/cover/backend: move module discovery into separate file

elf.go is already quite large and messy.
Module discovery is a well separatable chunk of logic,
move it to a dedicated file.
No code changes.

2 files changed, 119 insertions, 105 deletions

diff --git a/pkg/cover/backend/elf.go b/pkg/cover/backend/elf.go
index 00b8bb776..8d24542c2 100644
--- a/pkg/cover/backend/elf.go
+++ b/pkg/cover/backend/elf.go
@@ -11,7 +11,6 @@ import (
 	"encoding/binary"
 	"fmt"
 	"io/ioutil"
-	"os"
 	"path/filepath"
 	"runtime"
 	"sort"
@@ -135,110 +134,6 @@ func makeELF(target *targets.Target, srcDir, buildDir string,
 	return impl, nil
 }
 
-func getModules(dirs []string, modules []*Module) {
-	byName := make(map[string]*Module)
-	for _, mod := range modules {
-		byName[mod.Name] = mod
-	}
-	files := findModulePaths(dirs)
-	for _, path := range files {
-		name := strings.TrimSuffix(filepath.Base(path), ".ko")
-		if module := byName[name]; module != nil {
-			if module.Path != "" {
-				continue
-			}
-			module.Path = path
-			continue
-		}
-		name, err := getModuleName(path)
-		if err != nil {
-			log.Logf(0, "failed to get module name for %v: %v", path, err)
-			continue
-		}
-		if name == "" {
-			continue
-		}
-		if module := byName[name]; module != nil {
-			if module.Path != "" {
-				continue
-			}
-			module.Path = path
-		}
-	}
-	log.Logf(0, "kernel modules: %v", modules)
-}
-
-func findModulePaths(dirs []string) []string {
-	var files []string
-	for _, path := range dirs {
-		mfiles, err := walkModulePath(path)
-		if err != nil {
-			log.Logf(0, "failed to find modules in %v: %v", path, err)
-			continue
-		}
-		files = append(files, mfiles...)
-	}
-	return files
-}
-
-func walkModulePath(dir string) ([]string, error) {
-	files := []string{}
-	err := filepath.Walk(dir, func(path string, f os.FileInfo, err error) error {
-		if filepath.Ext(path) == ".ko" {
-			files = append(files, path)
-		}
-		return nil
-	})
-	return files, err
-}
-
-func getModuleName(path string) (string, error) {
-	file, err := elf.Open(path)
-	if err != nil {
-		return "", fmt.Errorf("failed to open %v: %v", path, err)
-	}
-	defer file.Close()
-	section := file.Section(".modinfo")
-	if section == nil {
-		return "", fmt.Errorf("no .modinfo section")
-	}
-	data, err := section.Data()
-	if err != nil {
-		return "", fmt.Errorf("failed to read .modinfo")
-	}
-	name := searchModuleName(data)
-	if name == "" {
-		section = file.Section(".gnu.linkonce.this_module")
-		if section == nil {
-			return "", fmt.Errorf("no .gnu.linkonce.this_module section")
-		}
-		data, err = section.Data()
-		if err != nil {
-			return "", fmt.Errorf("failed to read .gnu.linkonce.this_module: %v", err)
-		}
-		name = string(data)
-	}
-	return name, nil
-}
-
-func searchModuleName(data []byte) string {
-	data = append([]byte{0}, data...)
-	key := []byte("\x00name=")
-	pos := bytes.Index(data, key)
-	if pos == -1 {
-		return ""
-	}
-	end := bytes.IndexByte(data[pos+len(key):], 0)
-	if end == -1 {
-		return ""
-	}
-	end = pos + len(key) + end
-	if end > len(data) {
-		return ""
-	}
-	return string(data[pos+len(key) : end])
-}
-
 type pcRange struct {
 	start uint64
 	end   uint64
diff --git a/pkg/cover/backend/modules.go b/pkg/cover/backend/modules.go
new file mode 100644
index 000000000..c7a75ed22
--- /dev/null
+++ b/pkg/cover/backend/modules.go
@@ -0,0 +1,119 @@
+// Copyright 2021 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 backend
+
+import (
+	"bytes"
+	"debug/elf"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/google/syzkaller/pkg/log"
+)
+
+func getModules(dirs []string, modules []*Module) {
+	byName := make(map[string]*Module)
+	for _, mod := range modules {
+		byName[mod.Name] = mod
+	}
+	files := findModulePaths(dirs)
+	for _, path := range files {
+		name := strings.TrimSuffix(filepath.Base(path), ".ko")
+		if module := byName[name]; module != nil {
+			if module.Path != "" {
+				continue
+			}
+			module.Path = path
+			continue
+		}
+		name, err := getModuleName(path)
+		if err != nil {
+			log.Logf(0, "failed to get module name for %v: %v", path, err)
+			continue
+		}
+		if name == "" {
+			continue
+		}
+		if module := byName[name]; module != nil {
+			if module.Path != "" {
+				continue
+			}
+			module.Path = path
+		}
+	}
+	log.Logf(0, "kernel modules: %v", modules)
+}
+
+func findModulePaths(dirs []string) []string {
+	var files []string
+	for _, path := range dirs {
+		mfiles, err := walkModulePath(path)
+		if err != nil {
+			log.Logf(0, "failed to find modules in %v: %v", path, err)
+			continue
+		}
+		files = append(files, mfiles...)
+	}
+	return files
+}
+
+func walkModulePath(dir string) ([]string, error) {
+	files := []string{}
+	err := filepath.Walk(dir, func(path string, f os.FileInfo, err error) error {
+		if filepath.Ext(path) == ".ko" {
+			files = append(files, path)
+		}
+		return nil
+	})
+	return files, err
+}
+
+func getModuleName(path string) (string, error) {
+	file, err := elf.Open(path)
+	if err != nil {
+		return "", fmt.Errorf("failed to open %v: %v", path, err)
+	}
+	defer file.Close()
+	section := file.Section(".modinfo")
+	if section == nil {
+		return "", fmt.Errorf("no .modinfo section")
+	}
+	data, err := section.Data()
+	if err != nil {
+		return "", fmt.Errorf("failed to read .modinfo")
+	}
+	name := searchModuleName(data)
+	if name == "" {
+		section = file.Section(".gnu.linkonce.this_module")
+		if section == nil {
+			return "", fmt.Errorf("no .gnu.linkonce.this_module section")
+		}
+		data, err = section.Data()
+		if err != nil {
+			return "", fmt.Errorf("failed to read .gnu.linkonce.this_module: %v", err)
+		}
+		name = string(data)
+	}
+	return name, nil
+}
+
+func searchModuleName(data []byte) string {
+	data = append([]byte{0}, data...)
+	key := []byte("\x00name=")
+	pos := bytes.Index(data, key)
+	if pos == -1 {
+		return ""
+	}
+	end := bytes.IndexByte(data[pos+len(key):], 0)
+	if end == -1 {
+		return ""
+	}
+	end = pos + len(key) + end
+	if end > len(data) {
+		return ""
+	}
+	return string(data[pos+len(key) : end])
+}