Split processing into individual calls, add information and only rename if main option returns anything

main.go

@@ -13,11 +13,12 @@ func main() {
 		err         error
 		mainlog     = log.New(os.Stderr, "net-predictable: ", log.Lmsgprefix|log.Ltime)
 		ifnparam    string
-		force    bool
+		force, info bool
 		main        IfNameType
 	)
 	flag.StringVar(&ifnparam, "ifname", "", "Interface name to rename")
 	flag.BoolVar(&force, "force", false, "Force update name of interface")
+	flag.BoolVar(&info, "info", false, "Show interface details")
 	flag.IntVar((*int)(&main), "main", int(IfNameMAC), fmt.Sprintf("Main interface name to use: %v",
 		map[string]IfNameType{
 			"Kernel":   IfNameKern,
@@ -46,6 +47,7 @@ func main() {
 		return
 	}
 
+	mainlog.SetPrefix(fmt.Sprintf("net-predictable (%s): ", ifname))
 	var l netlink.Link
 	if l, err = netlink.LinkByName(ifname); err != nil {
 		mainlog.Fatalln("Interface", ifname, "doesn't exist or disappeared before it could be selected")
@@ -61,13 +63,24 @@ func main() {
 	if should, err = cif.shouldRun(); err != nil {
 		mainlog.Println(err)
 	}
-	if !force && !should {
+	if !info && (!force && !should) {
 		mainlog.Println("Interface is already renamed, exiting")
 		return
 	}
 
-	if err = cif.Process(); err != nil {
-		mainlog.Println("Failed to process interface:", err)
+	if err = cif.ProcMAC(); err != nil {
+		mainlog.Println("Failed to process interface MAC path:", err)
+	}
+
+	if err = cif.ProcLoc(); err != nil {
+		mainlog.Println("Failed to process interface PCI+USB path:", err)
+	}
+
+	// Just print information
+	if info {
+		mainlog.Println("Selected Interface:", ifname)
+		mainlog.Println("PCI+USB Name:", cif.names[IfNameLoc])
+		mainlog.Println("MAC Name:", cif.names[IfNameMAC])
 		return
 	}
 
@@ -75,11 +88,13 @@ func main() {
 	// This must be set before the next are following as altname cannot be added if a interface with the same name exists
 	if ifname == cif.names[main] {
 		mainlog.Println("Interface already named correctly, skipping")
-	} else {
+	} else if cif.names[main] != "" {
 		mainlog.Printf("Renaming %s to %s\n", ifname, cif.names[main])
 		if err = netlink.LinkSetName(l, cif.names[main]); err != nil {
 			mainlog.Fatalf("Could not rename interface %s: %s\n", ifname, err)
 		}
+	} else {
+		mainlog.Println("Main interface naming method is unavailable for this interface, skipping")
 	}
 
 	// Alt names

misc.go

@@ -89,19 +89,3 @@ func (i iface) shouldRun() (should bool, err error) {
 	}
 	return
 }
-
-func (i iface) Process() (err error) {
-	if lerr := i.ProcLoc(); lerr != nil {
-		err = lerr
-	}
-	if lerr := i.ProcMAC(); lerr != nil {
-		err = lerr
-	}
-
-	// It can error but as long as we get a identifier along the path it's okay
-	if i.names[IfNameLoc] == "" && i.names[IfNameMAC] == "" {
-		return
-	}
-	err = nil
-	return
-}