add ParseCgroupFileUnified to get the unified path

AkihiroSuda · AkihiroSuda · commit dd81920d1b44 · 2022-05-26T12:17:01.000+09:00
Signed-off-by: Akihiro Suda &lt;akihiro.suda.cz@hco.ntt.co.jp&gt;
diff --git a/paths_test.go b/paths_test.go
@@ -102,7 +102,7 @@ func TestEmptySubsystem(t *testing.T) {
 	1:name=systemd:/user.slice/user-1000.slice/user@1000.service/gnome-terminal-server.service
 	0::/user.slice/user-1000.slice/user@1000.service/gnome-terminal-server.service`
 	r := strings.NewReader(data)
-	paths, err := parseCgroupFromReader(r)
+	paths, unified, err := parseCgroupFromReaderUnified(r)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -111,6 +111,10 @@ func TestEmptySubsystem(t *testing.T) {
 			t.Fatalf("empty subsystem for %q", path)
 		}
 	}
+	unifiedExpected := "/user.slice/user-1000.slice/user@1000.service/gnome-terminal-server.service"
+	if unified != unifiedExpected {
+		t.Fatalf("expected %q, got %q", unifiedExpected, unified)
+	}
 }
 
 func TestSystemd240(t *testing.T) {
@@ -127,7 +131,7 @@ func TestSystemd240(t *testing.T) {
 	1:name=systemd:/system.slice/docker.service
 	0::/system.slice/docker.service`
 	r := strings.NewReader(data)
-	paths, err := parseCgroupFromReader(r)
+	paths, unified, err := parseCgroupFromReaderUnified(r)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -140,4 +144,8 @@ func TestSystemd240(t *testing.T) {
 	if err != ErrControllerNotActive {
 		t.Fatalf("expected error %q but received %q", ErrControllerNotActive, err)
 	}
+	unifiedExpected := "/system.slice/docker.service"
+	if unified != unifiedExpected {
+		t.Fatalf("expected %q, got %q", unifiedExpected, unified)
+	}
 }
diff --git a/utils.go b/utils.go
@@ -262,18 +262,27 @@ func parseKV(raw string) (string, uint64, error) {
 // etc.
 //
 // The resulting map does not have an element for cgroup v2 unified hierarchy.
+// Use ParseCgroupFileUnified to get the unified path.
 func ParseCgroupFile(path string) (map[string]string, error) {
+	x, _, err := ParseCgroupFileUnified(path)
+	return x, err
+}
+
+// ParseCgroupFileUnified returns legacy subsystem paths as the first value,
+// and returns the unified path as the second value.
+func ParseCgroupFileUnified(path string) (map[string]string, string, error) {
 	f, err := os.Open(path)
 	if err != nil {
-		return nil, err
+		return nil, "", err
 	}
 	defer f.Close()
-	return parseCgroupFromReader(f)
+	return parseCgroupFromReaderUnified(f)
 }
 
-func parseCgroupFromReader(r io.Reader) (map[string]string, error) {
+func parseCgroupFromReaderUnified(r io.Reader) (map[string]string, string, error) {
 	var (
 		cgroups = make(map[string]string)
+		unified = ""
 		s       = bufio.NewScanner(r)
 	)
 	for s.Scan() {
@@ -282,18 +291,20 @@ func parseCgroupFromReader(r io.Reader) (map[string]string, error) {
 			parts = strings.SplitN(text, ":", 3)
 		)
 		if len(parts) < 3 {
-			return nil, fmt.Errorf("invalid cgroup entry: %q", text)
+			return nil, unified, fmt.Errorf("invalid cgroup entry: %q", text)
 		}
 		for _, subs := range strings.Split(parts[1], ",") {
-			if subs != "" {
+			if subs == "" {
+				unified = parts[2]
+			} else {
 				cgroups[subs] = parts[2]
 			}
 		}
 	}
 	if err := s.Err(); err != nil {
-		return nil, err
+		return nil, unified, err
 	}
-	return cgroups, nil
+	return cgroups, unified, nil
 }
 
 func getCgroupDestination(subsystem string) (string, error) {

Original file line number	Diff line number	Diff line change
`@@ -102,7 +102,7 @@ func TestEmptySubsystem(t *testing.T) {`
`102`	`102`	`1:name=systemd:/user.slice/user-1000.slice/[email protected]/gnome-terminal-server.service`
`103`	`103`	0::/user.slice/user-1000.slice/[email protected]/gnome-terminal-server.service`
`104`	`104`	`r := strings.NewReader(data)`
`105`		`- paths, err := parseCgroupFromReader(r)`
	`105`	`+ paths, unified, err := parseCgroupFromReaderUnified(r)`
`106`	`106`	`if err != nil {`
`107`	`107`	`t.Fatal(err)`
`108`	`108`	`}`
`@@ -111,6 +111,10 @@ func TestEmptySubsystem(t *testing.T) {`
`111`	`111`	`t.Fatalf("empty subsystem for %q", path)`
`112`	`112`	`}`
`113`	`113`	`}`
	`114`	`+ unifiedExpected := "/user.slice/user-1000.slice/[email protected]/gnome-terminal-server.service"`
	`115`	`+ if unified != unifiedExpected {`
	`116`	`+ t.Fatalf("expected %q, got %q", unifiedExpected, unified)`
	`117`	`+ }`
`114`	`118`	`}`
`115`	`119`
`116`	`120`	`func TestSystemd240(t *testing.T) {`
`@@ -127,7 +131,7 @@ func TestSystemd240(t *testing.T) {`
`127`	`131`	`1:name=systemd:/system.slice/docker.service`
`128`	`132`	0::/system.slice/docker.service`
`129`	`133`	`r := strings.NewReader(data)`
`130`		`- paths, err := parseCgroupFromReader(r)`
	`134`	`+ paths, unified, err := parseCgroupFromReaderUnified(r)`
`131`	`135`	`if err != nil {`
`132`	`136`	`t.Fatal(err)`
`133`	`137`	`}`
`@@ -140,4 +144,8 @@ func TestSystemd240(t *testing.T) {`
`140`	`144`	`if err != ErrControllerNotActive {`
`141`	`145`	`t.Fatalf("expected error %q but received %q", ErrControllerNotActive, err)`
`142`	`146`	`}`
	`147`	`+ unifiedExpected := "/system.slice/docker.service"`
	`148`	`+ if unified != unifiedExpected {`
	`149`	`+ t.Fatalf("expected %q, got %q", unifiedExpected, unified)`
	`150`	`+ }`
`143`	`151`	`}`
Original file line number	Diff line number	Diff line change
`@@ -262,18 +262,27 @@ func parseKV(raw string) (string, uint64, error) {`
`262`	`262`	`// etc.`
`263`	`263`	`//`
`264`	`264`	`// The resulting map does not have an element for cgroup v2 unified hierarchy.`
	`265`	`+// Use ParseCgroupFileUnified to get the unified path.`
`265`	`266`	`func ParseCgroupFile(path string) (map[string]string, error) {`
	`267`	`+ x, _, err := ParseCgroupFileUnified(path)`
	`268`	`+ return x, err`
	`269`	`+}`
	`270`	`+`
	`271`	`+// ParseCgroupFileUnified returns legacy subsystem paths as the first value,`
	`272`	`+// and returns the unified path as the second value.`
	`273`	`+func ParseCgroupFileUnified(path string) (map[string]string, string, error) {`
`266`	`274`	`f, err := os.Open(path)`
`267`	`275`	`if err != nil {`
`268`		`- return nil, err`
	`276`	`+ return nil, "", err`
`269`	`277`	`}`
`270`	`278`	`defer f.Close()`
`271`		`- return parseCgroupFromReader(f)`
	`279`	`+ return parseCgroupFromReaderUnified(f)`
`272`	`280`	`}`
`273`	`281`
`274`		`-func parseCgroupFromReader(r io.Reader) (map[string]string, error) {`
	`282`	`+func parseCgroupFromReaderUnified(r io.Reader) (map[string]string, string, error) {`
`275`	`283`	`var (`
`276`	`284`	`cgroups = make(map[string]string)`
	`285`	`+ unified = ""`
`277`	`286`	`s = bufio.NewScanner(r)`
`278`	`287`	`)`
`279`	`288`	`for s.Scan() {`
`@@ -282,18 +291,20 @@ func parseCgroupFromReader(r io.Reader) (map[string]string, error) {`
`282`	`291`	`parts = strings.SplitN(text, ":", 3)`
`283`	`292`	`)`
`284`	`293`	`if len(parts) < 3 {`
`285`		`- return nil, fmt.Errorf("invalid cgroup entry: %q", text)`
	`294`	`+ return nil, unified, fmt.Errorf("invalid cgroup entry: %q", text)`
`286`	`295`	`}`
`287`	`296`	`for _, subs := range strings.Split(parts[1], ",") {`
`288`		`- if subs != "" {`
	`297`	`+ if subs == "" {`
	`298`	`+ unified = parts[2]`
	`299`	`+ } else {`
`289`	`300`	`cgroups[subs] = parts[2]`
`290`	`301`	`}`
`291`	`302`	`}`
`292`	`303`	`}`
`293`	`304`	`if err := s.Err(); err != nil {`
`294`		`- return nil, err`
	`305`	`+ return nil, unified, err`
`295`	`306`	`}`
`296`		`- return cgroups, nil`
	`307`	`+ return cgroups, unified, nil`
`297`	`308`	`}`
`298`	`309`
`299`	`310`	`func getCgroupDestination(subsystem string) (string, error) {`