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avoid SetFileCompletionNotificationModes crash #101

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avoid SetFileCompletionNotificationModes crash #101

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52 changes: 49 additions & 3 deletions file.go
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Original file line number Diff line number Diff line change
Expand Up @@ -10,13 +10,56 @@ import (
"sync/atomic"
"syscall"
"time"
"unsafe"
)

//sys cancelIoEx(file syscall.Handle, o *syscall.Overlapped) (err error) = CancelIoEx
//sys createIoCompletionPort(file syscall.Handle, port syscall.Handle, key uintptr, threadCount uint32) (newport syscall.Handle, err error) = CreateIoCompletionPort
//sys getQueuedCompletionStatus(port syscall.Handle, bytes *uint32, key *uintptr, o **ioOperation, timeout uint32) (err error) = GetQueuedCompletionStatus
//sys setFileCompletionNotificationModes(h syscall.Handle, flags uint8) (err error) = SetFileCompletionNotificationModes

// --- copied from https://golang.org/src/internal/poll/fd_windows.go ---
// This package uses the SetFileCompletionNotificationModes Windows
// API to skip calling GetQueuedCompletionStatus if an IO operation
// completes synchronously. There is a known bug where
// SetFileCompletionNotificationModes crashes on some systems (see
// https://support.microsoft.com/kb/2568167 for details).

var useSetFileCompletionNotificationModes bool // determines is SetFileCompletionNotificationModes is present and safe to use

// checkSetFileCompletionNotificationModes verifies that
// SetFileCompletionNotificationModes Windows API is present
// on the system and is safe to use.
// See https://support.microsoft.com/kb/2568167 for details.
func checkSetFileCompletionNotificationModes() {
err := syscall.LoadSetFileCompletionNotificationModes()
if err != nil {
return
}
protos := [2]int32{syscall.IPPROTO_TCP, 0}
var buf [32]syscall.WSAProtocolInfo
len := uint32(unsafe.Sizeof(buf))
n, err := syscall.WSAEnumProtocols(&protos[0], &buf[0], &len)
if err != nil {
return
}
for i := int32(0); i < n; i++ {
if buf[i].ServiceFlags1&syscall.XP1_IFS_HANDLES == 0 {
return
}
}
useSetFileCompletionNotificationModes = true
}

func initFileCompletionNotificationModes() {
var d syscall.WSAData
syscall.WSAStartup(uint32(0x202), &d)

checkSetFileCompletionNotificationModes()
}

// END --- copied from https://golang.org/src/internal/poll/fd_windows.go ---

type atomicBool int32

func (b *atomicBool) isSet() bool { return atomic.LoadInt32((*int32)(b)) != 0 }
Expand Down Expand Up @@ -64,6 +107,7 @@ type ioOperation struct {
}

func initIo() {
initFileCompletionNotificationModes()
h, err := createIoCompletionPort(syscall.InvalidHandle, 0, 0, 0xffffffff)
if err != nil {
panic(err)
Expand Down Expand Up @@ -99,9 +143,11 @@ func makeWin32File(h syscall.Handle) (*win32File, error) {
if err != nil {
return nil, err
}
err = setFileCompletionNotificationModes(h, cFILE_SKIP_COMPLETION_PORT_ON_SUCCESS|cFILE_SKIP_SET_EVENT_ON_HANDLE)
if err != nil {
return nil, err
if useSetFileCompletionNotificationModes {
err = setFileCompletionNotificationModes(h, cFILE_SKIP_COMPLETION_PORT_ON_SUCCESS|cFILE_SKIP_SET_EVENT_ON_HANDLE)
if err != nil {
return nil, err
}
}
f.readDeadline.channel = make(timeoutChan)
f.writeDeadline.channel = make(timeoutChan)
Expand Down