os, net, crypto/x509: add hurd support

Patch by Svante Signell.
    
    Reviewed-on: https://go-review.googlesource.com/c/161519

From-SVN: r268604

gcc/go/gofrontend/MERGE

@@ -1,4 +1,4 @@
-db618eeabdcf1ba56861d21d5639ca4514cd6934
+28b65174d9c9163f4ab2cfaf70dca646f1a7611f
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

libgo/go/crypto/x509/root_hurd.go

@@ -0,0 +1,11 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+// This file is derived from root_linux.go
+
+package x509
+
+// Possible certificate files; stop after finding one.
+var certFiles = []string{
+	"/etc/ssl/certs/ca-certificates.crt", // Debian/Ubuntu/Gentoo etc.
+}

libgo/go/internal/poll/sendfile_glibc.go

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build hurd linux
+
 package poll
 
 import "syscall"

libgo/go/net/cgo_hurd.go

@@ -0,0 +1,17 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+// This file is derived from cgo_bsd.go
+
+// +build cgo,!netgo
+// +build hurd
+
+package net
+
+/*
+#include <netdb.h>
+*/
+
+import "syscall"
+
+const cgoAddrInfoFlags = syscall.AI_CANONNAME | syscall.AI_V4MAPPED | syscall.AI_ALL

libgo/go/net/sendfile_glibc.go

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build hurd linux
+
 package net
 
 import (

libgo/go/net/sockopt_hurd.go

@@ -0,0 +1,41 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package net
+
+import (
+	"os"
+	"syscall"
+)
+
+func setDefaultSockopts(s, family, sotype int, ipv6only bool) error {
+	if family == syscall.AF_INET6 && sotype != syscall.SOCK_RAW {
+		// Allow both IP versions even if the OS default
+		// is otherwise. Note that some operating systems
+		// never admit this option.
+		syscall.SetsockoptInt(s, syscall.IPPROTO_IPV6, syscall.IPV6_V6ONLY, boolint(ipv6only))
+	}
+	// Allow broadcast.
+	if err := syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_BROADCAST, 1); err != nil {
+		return os.NewSyscallError("setsockopt", err)
+	}
+	return nil
+}
+
+func setDefaultListenerSockopts(s int) error {
+	// Allow reuse of recently-used addresses.
+	if err := syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1); err != nil {
+		return os.NewSyscallError("setsockopt", err)
+	}
+	return nil
+}
+
+func setDefaultMulticastSockopts(s int) error {
+	// Allow multicast UDP and raw IP datagram sockets to listen
+	// concurrently across multiple listeners.
+	if err := syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1); err != nil {
+		return os.NewSyscallError("setsockopt", err)
+	}
+	return nil
+}

libgo/go/os/executable_procfs.go

@@ -19,7 +19,7 @@ var executablePath, executablePathErr = func() (string, error) {
 	switch runtime.GOOS {
 	default:
 		return "", errors.New("Executable not implemented for " + runtime.GOOS)
-	case "linux", "android":
+	case "hurd", "linux", "android":
 		procfn = "/proc/self/exe"
 	case "netbsd":
 		procfn = "/proc/curproc/exe"

libgo/go/os/pipe_glibc.go

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build hurd linux
+
 package os
 
 import "syscall"