merge #3876 into opencontainers/runc:main

Chethan Suresh (1):
  Support time namespace

LGTMs: kolyskin cyphar
Closes #3876

libcontainer/container_linux.go

@@ -1191,6 +1191,18 @@ func (c *Container) bootstrapData(cloneFlags uintptr, nsMaps map[configs.Namespa
 		})
 	}
 
+	// write boottime and monotonic time ns offsets.
+	if c.config.Namespaces.Contains(configs.NEWTIME) && c.config.TimeOffsets != nil {
+		var offsetSpec bytes.Buffer
+		for clock, offset := range c.config.TimeOffsets {
+			fmt.Fprintf(&offsetSpec, "%s %d %d\n", clock, offset.Secs, offset.Nanosecs)
+		}
+		r.AddData(&Bytemsg{
+			Type:  TimeOffsetsAttr,
+			Value: offsetSpec.Bytes(),
+		})
+	}
+
 	return bytes.NewReader(r.Serialize()), nil
 }