net: remove fallback path in sysSocket

Support for operating system versions requiring this fallback path was
dropped from recent Go versions. The minimum Linux kernel version is
2.6.32 as of Go 1.18. FreeBSD 10 is no longer supported as of Go 1.13.

Change-Id: I7e74768146dd43a36d0d26fcb08eed9ace82189f
Reviewed-on: https://go-review.googlesource.com/c/go/+/403634
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: David Chase <drchase@google.com>

diff --git a/src/net/sock_cloexec.go b/src/net/sock_cloexec.go
index f4c116502884b978aa59d5db59aa9d3a72c53e8e..3f1cc9827aa3636de3a1bb6e42e5e599a6c322a6 100644 (file)
--- a/src/net/sock_cloexec.go
+++ b/src/net/sock_cloexec.go
@@ -10,7 +10,6 @@
 package net
 
 import (
-       "internal/poll"
        "os"
        "syscall"
 )
@@ -19,32 +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)
-       // On Linux the SOCK_NONBLOCK and SOCK_CLOEXEC flags were
-       // introduced in 2.6.27 kernel and on FreeBSD both flags were
-       // introduced in 10 kernel. If we get an EINVAL error on Linux
-       // or EPROTONOSUPPORT error on FreeBSD, fall back to using
-       // socket without them.
-       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
 }