network: error out on missing or unknown interface

This was caused by commit fc9ce46483fc4d -- if the user has no interface
defined but also has no legacy variables defined, our legacy check
fails, and we try to bring up the network using an empty declaration.
Add in an additional safeguard of checking sysfs to see that the
interface really does exist.

Fixes FS#25671

Signed-off-by: Dave Reisner <dreisner@archlinux.org>

1 files changed, 16 insertions, 0 deletions

diff --git a/network b/network
index 4fafb97..b94d170 100755
--- a/network
+++ b/network
@@ -23,7 +23,21 @@ deprecated() {
 	printf "  connection, or use a utility such as netcfg.\n"
 }
 
+have_interface() {
+	if [[ -z $1 ]]; then
+		printf "\n${C_FAIL}Error:${C_CLEAR} \`interface' is undefined in /etc/rc.conf\n"
+		return 1
+	fi
+
+	if [[ ! -d /sys/class/net/$1 ]]; then
+		printf "\n${C_FAIL}Error:${C_CLEAR} unknown interface in /etc/rc.conf: \`%s'\n" "$1"
+		return 1
+	fi
+}
+
 network_up() {
+	have_interface "$interface" || return 1
+
 	ip link set dev $interface up || return 1
 
 	if [[ $address ]]; then
@@ -35,6 +49,8 @@ network_up() {
 }
 
 network_down() {
+	have_interface "$interface" || return 1
+
 	if [[ -f /var/run/dhcpcd-$interface.pid ]]; then
 		dhcpcd -k $interface || return 1
 	else