From a74a29bc937cf75c1af4166e746df49ef53b2fc2 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Thu, 23 May 2019 14:53:44 +0200 Subject: ipc: use simplified fork of winio --- ipc/winpipe/file.go | 322 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 322 insertions(+) create mode 100644 ipc/winpipe/file.go (limited to 'ipc/winpipe/file.go') diff --git a/ipc/winpipe/file.go b/ipc/winpipe/file.go new file mode 100644 index 0000000..d25621c --- /dev/null +++ b/ipc/winpipe/file.go @@ -0,0 +1,322 @@ +// +build windows + +/* SPDX-License-Identifier: MIT + * + * Copyright (C) 2005 Microsoft + * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved. + */ +package winpipe + +import ( + "errors" + "io" + "runtime" + "sync" + "sync/atomic" + "syscall" + "time" +) + +//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 +//sys wsaGetOverlappedResult(h syscall.Handle, o *syscall.Overlapped, bytes *uint32, wait bool, flags *uint32) (err error) = ws2_32.WSAGetOverlappedResult + +type atomicBool int32 + +func (b *atomicBool) isSet() bool { return atomic.LoadInt32((*int32)(b)) != 0 } +func (b *atomicBool) setFalse() { atomic.StoreInt32((*int32)(b), 0) } +func (b *atomicBool) setTrue() { atomic.StoreInt32((*int32)(b), 1) } +func (b *atomicBool) swap(new bool) bool { + var newInt int32 + if new { + newInt = 1 + } + return atomic.SwapInt32((*int32)(b), newInt) == 1 +} + +const ( + cFILE_SKIP_COMPLETION_PORT_ON_SUCCESS = 1 + cFILE_SKIP_SET_EVENT_ON_HANDLE = 2 +) + +var ( + ErrFileClosed = errors.New("file has already been closed") + ErrTimeout = &timeoutError{} +) + +type timeoutError struct{} + +func (e *timeoutError) Error() string { return "i/o timeout" } +func (e *timeoutError) Timeout() bool { return true } +func (e *timeoutError) Temporary() bool { return true } + +type timeoutChan chan struct{} + +var ioInitOnce sync.Once +var ioCompletionPort syscall.Handle + +// ioResult contains the result of an asynchronous IO operation +type ioResult struct { + bytes uint32 + err error +} + +// ioOperation represents an outstanding asynchronous Win32 IO +type ioOperation struct { + o syscall.Overlapped + ch chan ioResult +} + +func initIo() { + h, err := createIoCompletionPort(syscall.InvalidHandle, 0, 0, 0xffffffff) + if err != nil { + panic(err) + } + ioCompletionPort = h + go ioCompletionProcessor(h) +} + +// win32File implements Reader, Writer, and Closer on a Win32 handle without blocking in a syscall. +// It takes ownership of this handle and will close it if it is garbage collected. +type win32File struct { + handle syscall.Handle + wg sync.WaitGroup + wgLock sync.RWMutex + closing atomicBool + socket bool + readDeadline deadlineHandler + writeDeadline deadlineHandler +} + +type deadlineHandler struct { + setLock sync.Mutex + channel timeoutChan + channelLock sync.RWMutex + timer *time.Timer + timedout atomicBool +} + +// makeWin32File makes a new win32File from an existing file handle +func makeWin32File(h syscall.Handle) (*win32File, error) { + f := &win32File{handle: h} + ioInitOnce.Do(initIo) + _, err := createIoCompletionPort(h, ioCompletionPort, 0, 0xffffffff) + 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 + } + f.readDeadline.channel = make(timeoutChan) + f.writeDeadline.channel = make(timeoutChan) + return f, nil +} + +func MakeOpenFile(h syscall.Handle) (io.ReadWriteCloser, error) { + return makeWin32File(h) +} + +// closeHandle closes the resources associated with a Win32 handle +func (f *win32File) closeHandle() { + f.wgLock.Lock() + // Atomically set that we are closing, releasing the resources only once. + if !f.closing.swap(true) { + f.wgLock.Unlock() + // cancel all IO and wait for it to complete + cancelIoEx(f.handle, nil) + f.wg.Wait() + // at this point, no new IO can start + syscall.Close(f.handle) + f.handle = 0 + } else { + f.wgLock.Unlock() + } +} + +// Close closes a win32File. +func (f *win32File) Close() error { + f.closeHandle() + return nil +} + +// prepareIo prepares for a new IO operation. +// The caller must call f.wg.Done() when the IO is finished, prior to Close() returning. +func (f *win32File) prepareIo() (*ioOperation, error) { + f.wgLock.RLock() + if f.closing.isSet() { + f.wgLock.RUnlock() + return nil, ErrFileClosed + } + f.wg.Add(1) + f.wgLock.RUnlock() + c := &ioOperation{} + c.ch = make(chan ioResult) + return c, nil +} + +// ioCompletionProcessor processes completed async IOs forever +func ioCompletionProcessor(h syscall.Handle) { + for { + var bytes uint32 + var key uintptr + var op *ioOperation + err := getQueuedCompletionStatus(h, &bytes, &key, &op, syscall.INFINITE) + if op == nil { + panic(err) + } + op.ch <- ioResult{bytes, err} + } +} + +// asyncIo processes the return value from ReadFile or WriteFile, blocking until +// the operation has actually completed. +func (f *win32File) asyncIo(c *ioOperation, d *deadlineHandler, bytes uint32, err error) (int, error) { + if err != syscall.ERROR_IO_PENDING { + return int(bytes), err + } + + if f.closing.isSet() { + cancelIoEx(f.handle, &c.o) + } + + var timeout timeoutChan + if d != nil { + d.channelLock.Lock() + timeout = d.channel + d.channelLock.Unlock() + } + + var r ioResult + select { + case r = <-c.ch: + err = r.err + if err == syscall.ERROR_OPERATION_ABORTED { + if f.closing.isSet() { + err = ErrFileClosed + } + } else if err != nil && f.socket { + // err is from Win32. Query the overlapped structure to get the winsock error. + var bytes, flags uint32 + err = wsaGetOverlappedResult(f.handle, &c.o, &bytes, false, &flags) + } + case <-timeout: + cancelIoEx(f.handle, &c.o) + r = <-c.ch + err = r.err + if err == syscall.ERROR_OPERATION_ABORTED { + err = ErrTimeout + } + } + + // runtime.KeepAlive is needed, as c is passed via native + // code to ioCompletionProcessor, c must remain alive + // until the channel read is complete. + runtime.KeepAlive(c) + return int(r.bytes), err +} + +// Read reads from a file handle. +func (f *win32File) Read(b []byte) (int, error) { + c, err := f.prepareIo() + if err != nil { + return 0, err + } + defer f.wg.Done() + + if f.readDeadline.timedout.isSet() { + return 0, ErrTimeout + } + + var bytes uint32 + err = syscall.ReadFile(f.handle, b, &bytes, &c.o) + n, err := f.asyncIo(c, &f.readDeadline, bytes, err) + runtime.KeepAlive(b) + + // Handle EOF conditions. + if err == nil && n == 0 && len(b) != 0 { + return 0, io.EOF + } else if err == syscall.ERROR_BROKEN_PIPE { + return 0, io.EOF + } else { + return n, err + } +} + +// Write writes to a file handle. +func (f *win32File) Write(b []byte) (int, error) { + c, err := f.prepareIo() + if err != nil { + return 0, err + } + defer f.wg.Done() + + if f.writeDeadline.timedout.isSet() { + return 0, ErrTimeout + } + + var bytes uint32 + err = syscall.WriteFile(f.handle, b, &bytes, &c.o) + n, err := f.asyncIo(c, &f.writeDeadline, bytes, err) + runtime.KeepAlive(b) + return n, err +} + +func (f *win32File) SetReadDeadline(deadline time.Time) error { + return f.readDeadline.set(deadline) +} + +func (f *win32File) SetWriteDeadline(deadline time.Time) error { + return f.writeDeadline.set(deadline) +} + +func (f *win32File) Flush() error { + return syscall.FlushFileBuffers(f.handle) +} + +func (f *win32File) Fd() uintptr { + return uintptr(f.handle) +} + +func (d *deadlineHandler) set(deadline time.Time) error { + d.setLock.Lock() + defer d.setLock.Unlock() + + if d.timer != nil { + if !d.timer.Stop() { + <-d.channel + } + d.timer = nil + } + d.timedout.setFalse() + + select { + case <-d.channel: + d.channelLock.Lock() + d.channel = make(chan struct{}) + d.channelLock.Unlock() + default: + } + + if deadline.IsZero() { + return nil + } + + timeoutIO := func() { + d.timedout.setTrue() + close(d.channel) + } + + now := time.Now() + duration := deadline.Sub(now) + if deadline.After(now) { + // Deadline is in the future, set a timer to wait + d.timer = time.AfterFunc(duration, timeoutIO) + } else { + // Deadline is in the past. Cancel all pending IO now. + timeoutIO() + } + return nil +} -- cgit v1.2.3-59-g8ed1b