woodpecker/vendor/github.com/Microsoft/go-winio/pipe.go

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2017-03-05 07:57:06 +00:00
// +build windows
package winio
import (
"errors"
"io"
"net"
"os"
"syscall"
"time"
"unsafe"
)
//sys connectNamedPipe(pipe syscall.Handle, o *syscall.Overlapped) (err error) = ConnectNamedPipe
//sys createNamedPipe(name string, flags uint32, pipeMode uint32, maxInstances uint32, outSize uint32, inSize uint32, defaultTimeout uint32, sa *securityAttributes) (handle syscall.Handle, err error) [failretval==syscall.InvalidHandle] = CreateNamedPipeW
//sys createFile(name string, access uint32, mode uint32, sa *securityAttributes, createmode uint32, attrs uint32, templatefile syscall.Handle) (handle syscall.Handle, err error) [failretval==syscall.InvalidHandle] = CreateFileW
//sys waitNamedPipe(name string, timeout uint32) (err error) = WaitNamedPipeW
//sys getNamedPipeInfo(pipe syscall.Handle, flags *uint32, outSize *uint32, inSize *uint32, maxInstances *uint32) (err error) = GetNamedPipeInfo
//sys getNamedPipeHandleState(pipe syscall.Handle, state *uint32, curInstances *uint32, maxCollectionCount *uint32, collectDataTimeout *uint32, userName *uint16, maxUserNameSize uint32) (err error) = GetNamedPipeHandleStateW
type securityAttributes struct {
Length uint32
SecurityDescriptor *byte
InheritHandle uint32
}
const (
cERROR_PIPE_BUSY = syscall.Errno(231)
cERROR_PIPE_CONNECTED = syscall.Errno(535)
cERROR_SEM_TIMEOUT = syscall.Errno(121)
cPIPE_ACCESS_DUPLEX = 0x3
cFILE_FLAG_FIRST_PIPE_INSTANCE = 0x80000
cSECURITY_SQOS_PRESENT = 0x100000
cSECURITY_ANONYMOUS = 0
cPIPE_REJECT_REMOTE_CLIENTS = 0x8
cPIPE_UNLIMITED_INSTANCES = 255
cNMPWAIT_USE_DEFAULT_WAIT = 0
cNMPWAIT_NOWAIT = 1
cPIPE_TYPE_MESSAGE = 4
cPIPE_READMODE_MESSAGE = 2
)
var (
// ErrPipeListenerClosed is returned for pipe operations on listeners that have been closed.
// This error should match net.errClosing since docker takes a dependency on its text.
ErrPipeListenerClosed = errors.New("use of closed network connection")
errPipeWriteClosed = errors.New("pipe has been closed for write")
)
type win32Pipe struct {
*win32File
path string
}
type win32MessageBytePipe struct {
win32Pipe
writeClosed bool
readEOF bool
}
type pipeAddress string
func (f *win32Pipe) LocalAddr() net.Addr {
return pipeAddress(f.path)
}
func (f *win32Pipe) RemoteAddr() net.Addr {
return pipeAddress(f.path)
}
func (f *win32Pipe) SetDeadline(t time.Time) error {
f.SetReadDeadline(t)
f.SetWriteDeadline(t)
return nil
}
// CloseWrite closes the write side of a message pipe in byte mode.
func (f *win32MessageBytePipe) CloseWrite() error {
if f.writeClosed {
return errPipeWriteClosed
}
_, err := f.win32File.Write(nil)
if err != nil {
return err
}
f.writeClosed = true
return nil
}
// Write writes bytes to a message pipe in byte mode. Zero-byte writes are ignored, since
// they are used to implement CloseWrite().
func (f *win32MessageBytePipe) Write(b []byte) (int, error) {
if f.writeClosed {
return 0, errPipeWriteClosed
}
if len(b) == 0 {
return 0, nil
}
return f.win32File.Write(b)
}
// Read reads bytes from a message pipe in byte mode. A read of a zero-byte message on a message
// mode pipe will return io.EOF, as will all subsequent reads.
func (f *win32MessageBytePipe) Read(b []byte) (int, error) {
if f.readEOF {
return 0, io.EOF
}
n, err := f.win32File.Read(b)
if err == io.EOF {
// If this was the result of a zero-byte read, then
// it is possible that the read was due to a zero-size
// message. Since we are simulating CloseWrite with a
// zero-byte message, ensure that all future Read() calls
// also return EOF.
f.readEOF = true
}
return n, err
}
func (s pipeAddress) Network() string {
return "pipe"
}
func (s pipeAddress) String() string {
return string(s)
}
// DialPipe connects to a named pipe by path, timing out if the connection
// takes longer than the specified duration. If timeout is nil, then the timeout
// is the default timeout established by the pipe server.
func DialPipe(path string, timeout *time.Duration) (net.Conn, error) {
var absTimeout time.Time
if timeout != nil {
absTimeout = time.Now().Add(*timeout)
}
var err error
var h syscall.Handle
for {
h, err = createFile(path, syscall.GENERIC_READ|syscall.GENERIC_WRITE, 0, nil, syscall.OPEN_EXISTING, syscall.FILE_FLAG_OVERLAPPED|cSECURITY_SQOS_PRESENT|cSECURITY_ANONYMOUS, 0)
if err != cERROR_PIPE_BUSY {
break
}
now := time.Now()
var ms uint32
if absTimeout.IsZero() {
ms = cNMPWAIT_USE_DEFAULT_WAIT
} else if now.After(absTimeout) {
ms = cNMPWAIT_NOWAIT
} else {
ms = uint32(absTimeout.Sub(now).Nanoseconds() / 1000 / 1000)
}
err = waitNamedPipe(path, ms)
if err != nil {
if err == cERROR_SEM_TIMEOUT {
return nil, ErrTimeout
}
break
}
}
if err != nil {
return nil, &os.PathError{Op: "open", Path: path, Err: err}
}
var flags uint32
err = getNamedPipeInfo(h, &flags, nil, nil, nil)
if err != nil {
return nil, err
}
var state uint32
err = getNamedPipeHandleState(h, &state, nil, nil, nil, nil, 0)
if err != nil {
return nil, err
}
if state&cPIPE_READMODE_MESSAGE != 0 {
return nil, &os.PathError{Op: "open", Path: path, Err: errors.New("message readmode pipes not supported")}
}
f, err := makeWin32File(h)
if err != nil {
syscall.Close(h)
return nil, err
}
// If the pipe is in message mode, return a message byte pipe, which
// supports CloseWrite().
if flags&cPIPE_TYPE_MESSAGE != 0 {
return &win32MessageBytePipe{
win32Pipe: win32Pipe{win32File: f, path: path},
}, nil
}
return &win32Pipe{win32File: f, path: path}, nil
}
type acceptResponse struct {
f *win32File
err error
}
type win32PipeListener struct {
firstHandle syscall.Handle
path string
securityDescriptor []byte
config PipeConfig
acceptCh chan (chan acceptResponse)
closeCh chan int
doneCh chan int
}
func makeServerPipeHandle(path string, securityDescriptor []byte, c *PipeConfig, first bool) (syscall.Handle, error) {
var flags uint32 = cPIPE_ACCESS_DUPLEX | syscall.FILE_FLAG_OVERLAPPED
if first {
flags |= cFILE_FLAG_FIRST_PIPE_INSTANCE
}
var mode uint32 = cPIPE_REJECT_REMOTE_CLIENTS
if c.MessageMode {
mode |= cPIPE_TYPE_MESSAGE
}
var sa securityAttributes
sa.Length = uint32(unsafe.Sizeof(sa))
if securityDescriptor != nil {
sa.SecurityDescriptor = &securityDescriptor[0]
}
h, err := createNamedPipe(path, flags, mode, cPIPE_UNLIMITED_INSTANCES, uint32(c.OutputBufferSize), uint32(c.InputBufferSize), 0, &sa)
if err != nil {
return 0, &os.PathError{Op: "open", Path: path, Err: err}
}
return h, nil
}
func (l *win32PipeListener) makeServerPipe() (*win32File, error) {
h, err := makeServerPipeHandle(l.path, l.securityDescriptor, &l.config, false)
if err != nil {
return nil, err
}
f, err := makeWin32File(h)
if err != nil {
syscall.Close(h)
return nil, err
}
return f, nil
}
func (l *win32PipeListener) listenerRoutine() {
closed := false
for !closed {
select {
case <-l.closeCh:
closed = true
case responseCh := <-l.acceptCh:
p, err := l.makeServerPipe()
if err == nil {
// Wait for the client to connect.
ch := make(chan error)
go func() {
ch <- connectPipe(p)
}()
select {
case err = <-ch:
if err != nil {
p.Close()
p = nil
}
case <-l.closeCh:
// Abort the connect request by closing the handle.
p.Close()
p = nil
err = <-ch
if err == nil || err == ErrFileClosed {
err = ErrPipeListenerClosed
}
closed = true
}
}
responseCh <- acceptResponse{p, err}
}
}
syscall.Close(l.firstHandle)
l.firstHandle = 0
// Notify Close() and Accept() callers that the handle has been closed.
close(l.doneCh)
}
// PipeConfig contain configuration for the pipe listener.
type PipeConfig struct {
// SecurityDescriptor contains a Windows security descriptor in SDDL format.
SecurityDescriptor string
// MessageMode determines whether the pipe is in byte or message mode. In either
// case the pipe is read in byte mode by default. The only practical difference in
// this implementation is that CloseWrite() is only supported for message mode pipes;
// CloseWrite() is implemented as a zero-byte write, but zero-byte writes are only
// transferred to the reader (and returned as io.EOF in this implementation)
// when the pipe is in message mode.
MessageMode bool
// InputBufferSize specifies the size the input buffer, in bytes.
InputBufferSize int32
// OutputBufferSize specifies the size the input buffer, in bytes.
OutputBufferSize int32
}
// ListenPipe creates a listener on a Windows named pipe path, e.g. \\.\pipe\mypipe.
// The pipe must not already exist.
func ListenPipe(path string, c *PipeConfig) (net.Listener, error) {
var (
sd []byte
err error
)
if c == nil {
c = &PipeConfig{}
}
if c.SecurityDescriptor != "" {
sd, err = SddlToSecurityDescriptor(c.SecurityDescriptor)
if err != nil {
return nil, err
}
}
h, err := makeServerPipeHandle(path, sd, c, true)
if err != nil {
return nil, err
}
// Immediately open and then close a client handle so that the named pipe is
// created but not currently accepting connections.
h2, err := createFile(path, 0, 0, nil, syscall.OPEN_EXISTING, cSECURITY_SQOS_PRESENT|cSECURITY_ANONYMOUS, 0)
if err != nil {
syscall.Close(h)
return nil, err
}
syscall.Close(h2)
l := &win32PipeListener{
firstHandle: h,
path: path,
securityDescriptor: sd,
config: *c,
acceptCh: make(chan (chan acceptResponse)),
closeCh: make(chan int),
doneCh: make(chan int),
}
go l.listenerRoutine()
return l, nil
}
func connectPipe(p *win32File) error {
c, err := p.prepareIo()
if err != nil {
return err
}
err = connectNamedPipe(p.handle, &c.o)
_, err = p.asyncIo(c, time.Time{}, 0, err)
if err != nil && err != cERROR_PIPE_CONNECTED {
return err
}
return nil
}
func (l *win32PipeListener) Accept() (net.Conn, error) {
ch := make(chan acceptResponse)
select {
case l.acceptCh <- ch:
response := <-ch
err := response.err
if err != nil {
return nil, err
}
if l.config.MessageMode {
return &win32MessageBytePipe{
win32Pipe: win32Pipe{win32File: response.f, path: l.path},
}, nil
}
return &win32Pipe{win32File: response.f, path: l.path}, nil
case <-l.doneCh:
return nil, ErrPipeListenerClosed
}
}
func (l *win32PipeListener) Close() error {
select {
case l.closeCh <- 1:
<-l.doneCh
case <-l.doneCh:
}
return nil
}
func (l *win32PipeListener) Addr() net.Addr {
return pipeAddress(l.path)
}