| // Copyright 2013 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 accept for platforms that provide a fast path for |
| // setting SetNonblock and CloseOnExec. |
| |
| //go:build dragonfly || freebsd || hurd || illumos || linux || netbsd || openbsd |
| |
| package poll |
| |
| import "syscall" |
| |
| // Wrapper around the accept system call that marks the returned file |
| // descriptor as nonblocking and close-on-exec. |
| func accept(s int) (int, syscall.Sockaddr, string, error) { |
| ns, sa, err := Accept4Func(s, syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC) |
| // On Linux the accept4 system call was introduced in 2.6.28 |
| // kernel and on FreeBSD it was introduced in 10 kernel. If we |
| // get an ENOSYS error on both Linux and FreeBSD, or EINVAL |
| // error on Linux, fall back to using accept. |
| switch err { |
| case nil: |
| return ns, sa, "", nil |
| default: // errors other than the ones listed |
| return -1, sa, "accept4", err |
| case syscall.ENOSYS: // syscall missing |
| case syscall.EINVAL: // some Linux use this instead of ENOSYS |
| case syscall.EACCES: // some Linux use this instead of ENOSYS |
| case syscall.EFAULT: // some Linux use this instead of ENOSYS |
| } |
| |
| // See ../syscall/exec_unix.go for description of ForkLock. |
| // It is probably okay to hold the lock across syscall.Accept |
| // because we have put fd.sysfd into non-blocking mode. |
| // However, a call to the File method will put it back into |
| // blocking mode. We can't take that risk, so no use of ForkLock here. |
| ns, sa, err = AcceptFunc(s) |
| if err == nil { |
| syscall.CloseOnExec(ns) |
| } |
| if err != nil { |
| return -1, nil, "accept", err |
| } |
| if err = syscall.SetNonblock(ns, true); err != nil { |
| CloseFunc(ns) |
| return -1, nil, "setnonblock", err |
| } |
| return ns, sa, "", nil |
| } |