pkg/sysinfo: add detection for time-namespaces support

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

pkg/sysinfo/cgroup2_linux.go

@@ -26,6 +26,7 @@ func newV2(options ...Opt) *SysInfo {
 		applyAppArmorInfo,
 		applySeccompInfo,
 		applyCgroupNsInfo,
+		applyTimeNsInfo,
 	}
 
 	m, err := cgroupsV2.Load(sysInfo.cg2GroupPath)

pkg/sysinfo/sysinfo.go

@@ -21,6 +21,9 @@ type SysInfo struct {
 	// Whether the kernel supports cgroup namespaces or not
 	CgroupNamespaces bool
 
+	// TimeNamespaces indicates whether the kernel supports time namespaces.
+	TimeNamespaces bool
+
 	// Whether IPv4 forwarding is supported or not, if this was disabled, networking will not work
 	IPv4ForwardingDisabled bool
 

pkg/sysinfo/sysinfo_linux.go

@@ -105,6 +105,7 @@ func newV1() *SysInfo {
 		applyAppArmorInfo,
 		applySeccompInfo,
 		applyCgroupNsInfo,
+		applyTimeNsInfo,
 	}
 
 	sysInfo.cgMounts, err = findCgroupV1Mountpoints()
@@ -283,6 +284,11 @@ func applyCgroupNsInfo(info *SysInfo) {
 	info.CgroupNamespaces = cgroupnsSupported()
 }
 
+// applyTimeNsInfo adds whether time namespaces are supported to the info.
+func applyTimeNsInfo(info *SysInfo) {
+	info.TimeNamespaces = timeNsSupported()
+}
+
 // applySeccompInfo checks if Seccomp is supported, via CONFIG_SECCOMP.
 func applySeccompInfo(info *SysInfo) {
 	info.Seccomp = seccomp.IsEnabled()
@@ -306,6 +312,14 @@ func cgroupnsSupported() bool {
 	return false
 }
 
+// timeNsSupported checks whether time namespaces are supported.
+func timeNsSupported() bool {
+	if _, err := os.Stat("/proc/self/ns/time"); !os.IsNotExist(err) {
+		return true
+	}
+	return false
+}
+
 func cgroupEnabled(mountPoint, name string) bool {
 	_, err := os.Stat(path.Join(mountPoint, name))
 	return err == nil

pkg/sysinfo/sysinfo_linux_test.go

@@ -64,6 +64,9 @@ func TestNew(t *testing.T) {
 	if expected := cgroupnsSupported(); sysInfo.CgroupNamespaces != expected {
 		t.Errorf("got CgroupNamespaces %v, wanted %v", sysInfo.CgroupNamespaces, expected)
 	}
+	if expected := timeNsSupported(); sysInfo.TimeNamespaces != expected {
+		t.Errorf("got TimeNamespaces %v, wanted %v", sysInfo.TimeNamespaces, expected)
+	}
 }
 
 func TestIsCpusetListAvailable(t *testing.T) {