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authorJason A. Donenfeld <Jason@zx2c4.com>2019-05-23 14:53:44 +0200
committerJason A. Donenfeld <Jason@zx2c4.com>2019-05-23 15:16:02 +0200
commita74a29bc937cf75c1af4166e746df49ef53b2fc2 (patch)
tree1d9c3ad1ca48fa370fd25b3a86007ec70466be4e /ipc/winpipe/file.go
parentsetupapi: trim "Get" from getters (diff)
downloadwireguard-go-a74a29bc937cf75c1af4166e746df49ef53b2fc2.tar.xz
wireguard-go-a74a29bc937cf75c1af4166e746df49ef53b2fc2.zip
ipc: use simplified fork of winio
Diffstat (limited to 'ipc/winpipe/file.go')
-rw-r--r--ipc/winpipe/file.go322
1 files changed, 322 insertions, 0 deletions
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
+}