libct/cg: rm GetInitCgroup[Path]

kolyshkin · kolyshkin · commit fd5debf3aa79 · 2023-04-04T11:19:25.000-07:00
These functions were added in ancient times, facilitating the docker-in-docker case when cgroup namespace was not available. As pointed out in commit 2b28b3c, using init 1 cgroup is not correct because it won't work in case of host PID namespace. The last user of GetInitCgroup was removed by commit 54e2021. GetInitCgroupPath was never used as far as I can see, nor was I able to find any external users. Remove both functions. Modify the comment in libct/cg/fs.subsysPath to not refer to GetInitCgroupPath. Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
diff --git a/libcontainer/cgroups/fs/paths.go b/libcontainer/cgroups/fs/paths.go
@@ -164,9 +164,8 @@ func subsysPath(root, inner, subsystem string) (string, error) {
 		return filepath.Join(root, filepath.Base(mnt), inner), nil
 	}
 
-	// Use GetOwnCgroupPath instead of GetInitCgroupPath, because the creating
-	// process could in container and shared pid namespace with host, and
-	// /proc/1/cgroup could point to whole other world of cgroups.
+	// Use GetOwnCgroupPath for dind-like cases, when cgroupns is not
+	// available. This is ugly.
 	parentPath, err := cgroups.GetOwnCgroupPath(subsystem)
 	if err != nil {
 		return "", err
diff --git a/libcontainer/cgroups/v1_utils.go b/libcontainer/cgroups/v1_utils.go
@@ -236,27 +236,6 @@ func GetOwnCgroupPath(subsystem string) (string, error) {
 	return getCgroupPathHelper(subsystem, cgroup)
 }
 
-func GetInitCgroup(subsystem string) (string, error) {
-	if IsCgroup2UnifiedMode() {
-		return "", errUnified
-	}
-	cgroups, err := ParseCgroupFile("/proc/1/cgroup")
-	if err != nil {
-		return "", err
-	}
-
-	return getControllerPath(subsystem, cgroups)
-}
-
-func GetInitCgroupPath(subsystem string) (string, error) {
-	cgroup, err := GetInitCgroup(subsystem)
-	if err != nil {
-		return "", err
-	}
-
-	return getCgroupPathHelper(subsystem, cgroup)
-}
-
 func getCgroupPathHelper(subsystem, cgroup string) (string, error) {
 	mnt, root, err := FindCgroupMountpointAndRoot("", subsystem)
 	if err != nil {
