Revert "rpc: avoid use of cgo by hard-coding maxPathSize (ethereum#27447

)"

This reverts commit 63eb2e9.

rpc/constants_unix.go

@@ -0,0 +1,34 @@
+// Copyright 2019 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+//go:build darwin || dragonfly || freebsd || linux || nacl || netbsd || openbsd || solaris
+// +build darwin dragonfly freebsd linux nacl netbsd openbsd solaris
+
+package rpc
+
+/*
+#include <sys/un.h>
+
+int max_socket_path_size() {
+struct sockaddr_un s;
+return sizeof(s.sun_path);
+}
+*/
+import "C"
+
+var (
+	max_path_size = C.max_socket_path_size()
+)

rpc/constants_unix_nocgo.go

@@ -0,0 +1,26 @@
+// Copyright 2019 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+//go:build !cgo && !windows
+// +build !cgo,!windows
+
+package rpc
+
+var (
+	//  On Linux, sun_path is 108 bytes in size
+	// see http://man7.org/linux/man-pages/man7/unix.7.html
+	max_path_size = 108
+)

rpc/ipc_unix.go

@@ -29,17 +29,11 @@ import (
 	"github.com/ethereum/go-ethereum/log"
 )
 
-const (
-	// On Linux, sun_path is 108 bytes in size
-	// see http://man7.org/linux/man-pages/man7/unix.7.html
-	maxPathSize = int(108)
-)
-
 // ipcListen will create a Unix socket on the given endpoint.
 func ipcListen(endpoint string) (net.Listener, error) {
 	// account for null-terminator too
-	if len(endpoint)+1 > maxPathSize {
-		log.Warn(fmt.Sprintf("The ipc endpoint is longer than %d characters. ", maxPathSize-1),
+	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)
 	}