On Linux, attempt to read from /sys/class/dmi/id/product_uuid first

before falling back to kernel.random.boot_id.

`/sys/class/dmi/id/product_uuid` is still managed by permissions, so
for root-run processes where `/sys/class/dmi/id/product_uuid` is
available, the host's UUID will be used instead, otherwise the UUID
from kernel.random.boot_id will be used instead.

host/host_linux.go

@@ -61,10 +61,21 @@ func Info() (*InfoStat, error) {
 		ret.Procs = numProcs
 	}
 
+	sysProductUUID := common.HostSys("class/dmi/id/product_uuid")
+	switch {
+	case common.PathExists(sysProductUUID):
+		lines, err := common.ReadLines(sysProductUUID)
+		if err == nil && len(lines) > 0 && lines[0] != "" {
+			ret.HostID = lines[0]
+			break
+		}
+		fallthrough
+	default:
 		values, err := common.DoSysctrl("kernel.random.boot_id")
 		if err == nil && len(values) == 1 && values[0] != "" {
 			ret.HostID = values[0]
 		}
+	}
 
 	return ret, nil
 }