net: separate the Solaris fast/slow path of setting SOCK_* from others

Along with the removal of the slow path from Linux and *BSD.

For #59359

Change-Id: I6c79594252e5e5f1c1c57c11e09458fcae3793d2
Reviewed-on: https://go-review.googlesource.com/c/go/+/577175
Reviewed-by: Damien Neil <dneil@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Andy Pan <panjf2000@gmail.com>

2 files changed, 48 insertions, 24 deletions

diff --git a/src/net/sock_cloexec.go b/src/net/sock_cloexec.go
index 9eeb89746b..043522f0b6 100644
--- a/src/net/sock_cloexec.go
+++ b/src/net/sock_cloexec.go
@@ -5,12 +5,11 @@
 // This file implements sysSocket for platforms that provide a fast path for
 // setting SetNonblock and CloseOnExec.
 
-//go:build dragonfly || freebsd || linux || netbsd || openbsd || solaris
+//go:build dragonfly || freebsd || linux || netbsd || openbsd
 
 package net
 
 import (
-	"internal/poll"
 	"os"
 	"syscall"
 )
@@ -19,30 +18,8 @@ import (
 // descriptor as nonblocking and close-on-exec.
 func sysSocket(family, sotype, proto int) (int, error) {
 	s, err := socketFunc(family, sotype|syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC, proto)
-	// TODO: We can remove the fallback on Linux and *BSD,
-	// as currently supported versions all support accept4
-	// with SOCK_CLOEXEC, but Solaris does not. See issue #59359.
-	switch err {
-	case nil:
-		return s, nil
-	default:
-		return -1, os.NewSyscallError("socket", err)
-	case syscall.EPROTONOSUPPORT, syscall.EINVAL:
-	}
-
-	// See ../syscall/exec_unix.go for description of ForkLock.
-	syscall.ForkLock.RLock()
-	s, err = socketFunc(family, sotype, proto)
-	if err == nil {
-		syscall.CloseOnExec(s)
-	}
-	syscall.ForkLock.RUnlock()
 	if err != nil {
 		return -1, os.NewSyscallError("socket", err)
 	}
-	if err = syscall.SetNonblock(s, true); err != nil {
-		poll.CloseFunc(s)
-		return -1, os.NewSyscallError("setnonblock", err)
-	}
 	return s, nil
 }
diff --git a/src/net/sock_cloexec_solaris.go b/src/net/sock_cloexec_solaris.go
new file mode 100644
index 0000000000..04c3cdf254
--- /dev/null
+++ b/src/net/sock_cloexec_solaris.go
@@ -0,0 +1,47 @@
+// Copyright 2024 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 implements sysSocket for platforms that provide a fast path for
+// setting SetNonblock and CloseOnExec, but don't necessarily support it.
+// Support for SOCK_* flags as part of the type parameter was added to Oracle
+// Solaris in the 11.4 release. Thus, on releases prior to 11.4, we fall back
+// to the combination of socket(3c) and fcntl(2).
+
+package net
+
+import (
+	"internal/poll"
+	"internal/syscall/unix"
+	"os"
+	"syscall"
+)
+
+// Wrapper around the socket system call that marks the returned file
+// descriptor as nonblocking and close-on-exec.
+func sysSocket(family, sotype, proto int) (int, error) {
+	// Perform a cheap test and try the fast path first.
+	if unix.SupportSockNonblockCloexec() {
+		s, err := socketFunc(family, sotype|syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC, proto)
+		if err != nil {
+			return -1, os.NewSyscallError("socket", err)
+		}
+		return s, nil
+	}
+
+	// See ../syscall/exec_unix.go for description of ForkLock.
+	syscall.ForkLock.RLock()
+	s, err := socketFunc(family, sotype, proto)
+	if err == nil {
+		syscall.CloseOnExec(s)
+	}
+	syscall.ForkLock.RUnlock()
+	if err != nil {
+		return -1, os.NewSyscallError("socket", err)
+	}
+	if err = syscall.SetNonblock(s, true); err != nil {
+		poll.CloseFunc(s)
+		return -1, os.NewSyscallError("setnonblock", err)
+	}
+	return s, nil
+}