go-fuzz: set fd inheritance properly for Go 1.17+ on Windows

During Go 1.17 development, fd inheritance on Windows was changed in:
    CL 288297 - "syscall: restrict inherited handles on Windows"
    https://golang.org/cl/288297

Running go-fuzz with Go 1.17 on at least some Windows versions caused errors like:
    "write to testee failed: write |1: The pipe is being closed"

The fix is to properly set SysProcAttr.AdditionalInheritedHandles, which is modeled
after the suggestion from Jason Donenfeld in CL 320050:
    https://go-review.googlesource.com/c/go/+/320050/-1..3#message-ed1be75fda3d32c5ff2bd037b951a875cb07c3db

Fixes dvyukov#328

.travis.yml

@@ -13,27 +13,27 @@ language: go
 matrix:
   include:
     - os: linux
-      go: "1.16.x"
+      go: "1.17.x"
     - os: linux
-      go: "1.15.x"
+      go: "1.16.x"
     - os: linux
       go: tip
     - os: linux
       go: tip
       env: SET_GO111MODULE=auto
     - os: osx
-      go: "1.16.x"
+      go: "1.17.x"
     - os: osx
-      go: "1.15.x"
+      go: "1.16.x"
     - os: osx
       go: tip
     - os: osx
       go: tip
       env: SET_GO111MODULE=auto
     - os: windows
-      go: "1.16.x"
+      go: "1.17.x"
     - os: windows
-      go: "1.15.x"
+      go: "1.16.x"
 
 # Install coreutils for the 'timeout(1)' utility on windows and osx.
 before_install:

go-fuzz/sys_go116_windows.go

@@ -0,0 +1,23 @@
+// Copyright 2015 go-fuzz project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+//go:build !go1.17
+// +build !go1.17
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"syscall"
+)
+
+func setupCommMapping(cmd *exec.Cmd, comm *Mapping, rOut, wIn *os.File) {
+	syscall.SetHandleInformation(syscall.Handle(comm.mapping), syscall.HANDLE_FLAG_INHERIT, 1)
+	syscall.SetHandleInformation(syscall.Handle(rOut.Fd()), syscall.HANDLE_FLAG_INHERIT, 1)
+	syscall.SetHandleInformation(syscall.Handle(wIn.Fd()), syscall.HANDLE_FLAG_INHERIT, 1)
+	cmd.Env = append(cmd.Env, fmt.Sprintf("GO_FUZZ_COMM_FD=%v", comm.mapping))
+	cmd.Env = append(cmd.Env, fmt.Sprintf("GO_FUZZ_IN_FD=%v", rOut.Fd()))
+	cmd.Env = append(cmd.Env, fmt.Sprintf("GO_FUZZ_OUT_FD=%v", wIn.Fd()))
+}

go-fuzz/sys_go117_windows.go

@@ -0,0 +1,31 @@
+// Copyright 2015 go-fuzz project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+//go:build go1.17
+// +build go1.17
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"syscall"
+)
+
+func setupCommMapping(cmd *exec.Cmd, comm *Mapping, rOut, wIn *os.File) {
+	syscall.SetHandleInformation(syscall.Handle(comm.mapping), syscall.HANDLE_FLAG_INHERIT, 1)
+	syscall.SetHandleInformation(syscall.Handle(rOut.Fd()), syscall.HANDLE_FLAG_INHERIT, 1)
+	syscall.SetHandleInformation(syscall.Handle(wIn.Fd()), syscall.HANDLE_FLAG_INHERIT, 1)
+	// Setting AdditionalInheritedHandles is required in Go 1.17+.
+	cmd.SysProcAttr = &syscall.SysProcAttr{
+		AdditionalInheritedHandles: []syscall.Handle{
+			syscall.Handle(wIn.Fd()),
+			syscall.Handle(rOut.Fd()),
+			syscall.Handle(comm.mapping),
+		},
+	}
+	cmd.Env = append(cmd.Env, fmt.Sprintf("GO_FUZZ_COMM_FD=%v", comm.mapping))
+	cmd.Env = append(cmd.Env, fmt.Sprintf("GO_FUZZ_IN_FD=%v", rOut.Fd()))
+	cmd.Env = append(cmd.Env, fmt.Sprintf("GO_FUZZ_OUT_FD=%v", wIn.Fd()))
+}

go-fuzz/sys_windows.go

@@ -4,10 +4,8 @@
 package main
 
 import (
-	"fmt"
 	"log"
 	"os"
-	"os/exec"
 	"reflect"
 	"syscall"
 	"unsafe"
@@ -47,12 +45,3 @@ func (m *Mapping) destroy() {
 	syscall.UnmapViewOfFile(m.addr)
 	syscall.CloseHandle(m.mapping)
 }
-
-func setupCommMapping(cmd *exec.Cmd, comm *Mapping, rOut, wIn *os.File) {
-	syscall.SetHandleInformation(syscall.Handle(comm.mapping), syscall.HANDLE_FLAG_INHERIT, 1)
-	syscall.SetHandleInformation(syscall.Handle(rOut.Fd()), syscall.HANDLE_FLAG_INHERIT, 1)
-	syscall.SetHandleInformation(syscall.Handle(wIn.Fd()), syscall.HANDLE_FLAG_INHERIT, 1)
-	cmd.Env = append(cmd.Env, fmt.Sprintf("GO_FUZZ_COMM_FD=%v", comm.mapping))
-	cmd.Env = append(cmd.Env, fmt.Sprintf("GO_FUZZ_IN_FD=%v", rOut.Fd()))
-	cmd.Env = append(cmd.Env, fmt.Sprintf("GO_FUZZ_OUT_FD=%v", wIn.Fd()))
-}