internal/poll, net, syscall: use accept4 on solaris

Solaris supports accept4 since version 11.4, see
https://docs.oracle.com/cd/E88353_01/html/E37843/accept4-3c.html
Use it in internal/poll.accept like on other platforms.

Change-Id: I3d9830a85e93bbbed60486247c2f91abc646371f
Reviewed-on: https://go-review.googlesource.com/c/go/+/403394
Reviewed-by: Ian Lance Taylor <[email protected]>
Auto-Submit: Ian Lance Taylor <[email protected]>
Run-TryBot: Tobias Klauser <[email protected]>
Reviewed-by: Benny Siegert <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Run-TryBot: Ian Lance Taylor <[email protected]>

Author: tklauser

src/internal/poll/hook_cloexec.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build dragonfly || freebsd || illumos || linux || netbsd || openbsd
+//go:build dragonfly || freebsd || linux || netbsd || openbsd || solaris
 
 package poll
 

src/internal/poll/sock_cloexec.go

@@ -5,7 +5,7 @@
 // This file implements accept for platforms that provide a fast path for
 // setting SetNonblock and CloseOnExec.
 
-//go:build dragonfly || freebsd || illumos || linux || netbsd || openbsd
+//go:build dragonfly || freebsd || linux || netbsd || openbsd || solaris
 
 package poll
 

src/internal/poll/sys_cloexec.go

@@ -5,7 +5,7 @@
 // This file implements accept for platforms that do not provide a fast path for
 // setting SetNonblock and CloseOnExec.
 
-//go:build aix || darwin || (js && wasm) || (solaris && !illumos)
+//go:build aix || darwin || (js && wasm)
 
 package poll
 

src/net/internal/socktest/sys_cloexec.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build dragonfly || freebsd || illumos || linux || netbsd || openbsd
+//go:build dragonfly || freebsd || linux || netbsd || openbsd || solaris
 
 package socktest
 

src/net/main_cloexec_test.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build dragonfly || freebsd || illumos || linux || netbsd || openbsd
+//go:build dragonfly || freebsd || linux || netbsd || openbsd || solaris
 
 package net
 

src/net/sock_cloexec.go

@@ -5,7 +5,7 @@
 // This file implements sysSocket for platforms that provide a fast path for
 // setting SetNonblock and CloseOnExec.
 
-//go:build dragonfly || freebsd || illumos || linux || netbsd || openbsd
+//go:build dragonfly || freebsd || linux || netbsd || openbsd || solaris
 
 package net
 

src/net/sys_cloexec.go

@@ -5,7 +5,7 @@
 // This file implements sysSocket for platforms that do not provide a fast path
 // for setting SetNonblock and CloseOnExec.
 
-//go:build aix || darwin || (solaris && !illumos)
+//go:build aix || darwin
 
 package net
 

src/runtime/cgo/cgo.go

@@ -21,7 +21,7 @@ package cgo
 #cgo openbsd LDFLAGS: -lpthread
 #cgo aix LDFLAGS: -Wl,-berok
 #cgo solaris LDFLAGS: -lxnet
-#cgo illumos LDFLAGS: -lsocket
+#cgo solaris LDFLAGS: -lsocket
 
 #cgo CFLAGS: -Wall -Werror
 

src/syscall/syscall_illumos.go

@@ -10,34 +10,11 @@ package syscall
 
 import "unsafe"
 
-//go:cgo_import_dynamic libc_accept4 accept4 "libsocket.so"
 //go:cgo_import_dynamic libc_flock flock "libc.so"
 
-//go:linkname procAccept4 libc_accept4
 //go:linkname procFlock libc_flock
 
-var (
-	procAccept4,
-	procFlock libcFunc
-)
-
-func Accept4(fd int, flags int) (int, Sockaddr, error) {
-	var rsa RawSockaddrAny
-	var addrlen _Socklen = SizeofSockaddrAny
-	nfd, _, errno := sysvicall6(uintptr(unsafe.Pointer(&procAccept4)), 4, uintptr(fd), uintptr(unsafe.Pointer(&rsa)), uintptr(unsafe.Pointer(&addrlen)), uintptr(flags), 0, 0)
-	if errno != 0 {
-		return 0, nil, errno
-	}
-	if addrlen > SizeofSockaddrAny {
-		panic("RawSockaddrAny too small")
-	}
-	sa, err := anyToSockaddr(&rsa)
-	if err != nil {
-		Close(int(nfd))
-		return 0, nil, err
-	}
-	return int(nfd), sa, nil
-}
+var procFlock libcFunc
 
 func Flock(fd int, how int) error {
 	_, _, errno := sysvicall6(uintptr(unsafe.Pointer(&procFlock)), 2, uintptr(fd), uintptr(how), 0, 0, 0, 0)

src/syscall/syscall_solaris.go

@@ -71,6 +71,26 @@ func Pipe2(p []int, flags int) error {
 	return err
 }
 
+//sys   accept4(s int, rsa *RawSockaddrAny, addrlen *_Socklen, flags int) (fd int, err error) = libsocket.accept4
+
+func Accept4(fd int, flags int) (int, Sockaddr, error) {
+	var rsa RawSockaddrAny
+	var addrlen _Socklen = SizeofSockaddrAny
+	nfd, err := accept4(fd, &rsa, &addrlen, flags)
+	if err != nil {
+		return 0, nil, err
+	}
+	if addrlen > SizeofSockaddrAny {
+		panic("RawSockaddrAny too small")
+	}
+	sa, err := anyToSockaddr(&rsa)
+	if err != nil {
+		Close(nfd)
+		return 0, nil, err
+	}
+	return nfd, sa, nil
+}
+
 func (sa *SockaddrInet4) sockaddr() (unsafe.Pointer, _Socklen, error) {
 	if sa.Port < 0 || sa.Port > 0xFFFF {
 		return nil, 0, EINVAL