rpc: fix off-by-one in ipc endpoint length check (#26614)

This change fixes a minor flaw in the check for ipc endpoint length. The max_path_size is the max path that an ipc endpoint can have, which is 208. However, that size concerns the null-terminated pathname, so we need to account for an extra null-character too.

rpc/ipc_unix.go

@@ -31,8 +31,9 @@ import (
 
 // ipcListen will create a Unix socket on the given endpoint.
 func ipcListen(endpoint string) (net.Listener, error) {
-	if len(endpoint) > int(max_path_size) {
+	// account for null-terminator too
-		log.Warn(fmt.Sprintf("The ipc endpoint is longer than %d characters. ", max_path_size),
+	if len(endpoint)+1 > int(max_path_size) {
+		log.Warn(fmt.Sprintf("The ipc endpoint is longer than %d characters. ", max_path_size-1),
 			"endpoint", endpoint)
 	}