dhcp: more intelligent default DHCP client detection

src/dhcp-manager/nm-dhcp-manager.c

@@ -251,6 +251,20 @@ nm_dhcp_manager_new (const char *client, GError **error)
 	NMDHCPManagerPrivate *priv;
 	DBusGConnection *g_connection;
 
+	/* Set some defaults based on build-time options */
+	if (!client) {
+		if (strlen (DHCLIENT_PATH) && g_file_test (DHCLIENT_PATH, G_FILE_TEST_EXISTS))
+			client = "dhclient";
+		else if (strlen (DHCPCD_PATH) && g_file_test (DHCPCD_PATH, G_FILE_TEST_EXISTS))
+			client = "dhcpcd";
+		else {
+			g_set_error_literal (error, 0, 0,
+			                     "no suitable DHCP client; see 'man NetworkManager'"
+			                     " to specify one.");
+			return NULL;
+		}
+	}
+
 	g_warn_if_fail (singleton == NULL);
 	g_return_val_if_fail (client != NULL, NULL);
 

src/main.c

@@ -652,7 +652,8 @@ main (int argc, char *argv[])
 		goto done;
 	}
 
-	dhcp_mgr = nm_dhcp_manager_new (dhcp ? dhcp : "dhclient", &error);
+	/* Initialize DHCP manager */
+	dhcp_mgr = nm_dhcp_manager_new (dhcp, &error);
 	if (!dhcp_mgr) {
 		nm_warning ("Failed to start the DHCP manager: %s.", error->message);
 		goto done;