fix(network-legacy): check if dhclient has --timeout option

dhclient's --timeout option is not upstream, so a pre-check is needed before
using it.

Author: aafeijoo-suse

modules.d/35network-legacy/dhcp-multi.sh

@@ -21,6 +21,13 @@ do_dhclient() {
     _timeout=$(getarg rd.net.timeout.dhcp=)
     _DHCPRETRY=$(getargnum 1 1 1000000000 rd.net.dhcp.retry=)
 
+    if [ -n "$_timeout" ]; then
+        if ! (dhclient --help 2>&1 | grep -q -F -- '--timeout' 2> /dev/null); then
+            warn "rd.net.timeout.dhcp has no effect because dhclient does not implement the --timeout option"
+            unset _timeout
+        fi
+    fi
+
     while [ $_COUNT -lt "$_DHCPRETRY" ]; do
         info "Starting dhcp for interface $netif"
         dhclient "$arg" \

modules.d/35network-legacy/ifup.sh

@@ -73,6 +73,13 @@ do_dhcp() {
         return 1
     fi
 
+    if [ -n "$_timeout" ]; then
+        if ! (dhclient --help 2>&1 | grep -q -F -- '--timeout' 2> /dev/null); then
+            warn "rd.net.timeout.dhcp has no effect because dhclient does not implement the --timeout option"
+            unset _timeout
+        fi
+    fi
+
     if [ ! -e /run/NetworkManager/conf.d/10-dracut-dhclient.conf ]; then
         mkdir -p /run/NetworkManager/conf.d
         echo '[main]' > /run/NetworkManager/conf.d/10-dracut-dhclient.conf