board/classic: generate interfaces.d, set hostname from qemu_fw_cfg

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

board/classic/rootfs/etc/network/interfaces.d/eth0

@@ -1,3 +0,0 @@
-auto eth0
-iface eth0 inet dhcp
-      pre-up ip link set eth0 group iface

board/classic/rootfs/lib/infix/swup

@@ -1,23 +1,27 @@
 #!/bin/sh
+# Factory default:
+#  1) all switch ports in VLAN 1 of br0
+#  2) no switch ports => DHCP on eth0
+#  3) no eth0
 
-# Factory default: all switch ports in VLAN 1 of br0
-# need to check for 'length > 0' because ip command
-# outputs empty json objects for non-port group ifs
-ports=$(ip -json link show group port | jq -r '.[].ifname | select(length > 0)' | tr "\n" " ")
-[ -f /etc/network/interfaces.d/br0 ] || [ -z "$ports" ] && exit 0
+create_bridge()
+{
+    nm=$1
+    shift
+    ports=$@
 
-touch /etc/network/interfaces.d/br0
-for port in $ports; do
-    cat <<-EOF >>/etc/network/interfaces.d/br0
+    touch "/etc/network/interfaces.d/$nm"
+    for port in $ports; do
+	cat <<-EOF >>"/etc/network/interfaces.d/$nm"
 		iface $port
 		    bridge-access 1
 		    post-up ip link set $port group port
-	EOF
-done
-cat <<-EOF >>/etc/network/interfaces.d/br0
+		EOF
+    done
+    cat <<-EOF >> "/etc/network/interfaces.d/$nm"
 
-	auto br0
-	iface br0
+	auto $nm
+	iface $nm
 	    bridge-ports $ports
 	    bridge-vlan-aware yes
 	    bridge-stp on
@@ -26,7 +30,33 @@ cat <<-EOF >>/etc/network/interfaces.d/br0
 	auto vlan1
 	iface vlan1 inet dhcp
 	    vlan-id 1
-	    vlan-raw-device br0
+	    vlan-raw-device $nm
 	    post-up ip link set vlan1 group iface
-EOF
-ip link set vlan1 group iface
+	EOF
+    ip link set vlan1 group iface
+}
+
+# Check if already set up
+[ -z "$(ls -A /etc/network/interfaces.d/)" ] || exit 0
+
+# Check for custom hostname from Qemu/Qeneth
+nm=$(cat /sys/firmware/qemu_fw_cfg/by_name/opt/hostname/raw)
+if [ -n "$nm" ]; then
+    hostnm "$nm"
+fi
+
+# need to check for 'length > 0' because ip command
+# outputs empty json objects for non-port group ifs
+ports=$(ip -json link show group port | jq -r '.[].ifname | select(length > 0)' | tr "\n" " ")
+if [ -n "$ports" ]; then
+    create_bridge br0 $ports
+else
+    ifaces=$(ip -json addr show  |jq -r '.[] | select(.link_type=="ether").ifname')
+    for iface in $ifaces; do
+	cat  <<-EOF > "/etc/network/interfaces.d/$iface"
+		auto $iface
+		iface $iface inet dhcp
+		    pre-up ip link set $iface group iface
+		EOF
+    done
+fi