//go:build windows
// +build windows
package winio
import (
"context"
"errors"
"fmt"
"io"
"net"
"os"
"runtime"
"time"
"unsafe"
"golang.org/x/sys/windows"
"github.com/Microsoft/go-winio/internal/fs"
)
//sys connectNamedPipe(pipe windows.Handle, o *windows.Overlapped) (err error) = ConnectNamedPipe
//sys createNamedPipe(name string, flags uint32, pipeMode uint32, maxInstances uint32, outSize uint32, inSize uint32, defaultTimeout uint32, sa *windows.SecurityAttributes) (handle windows.Handle, err error) [failretval==windows.InvalidHandle] = CreateNamedPipeW
//sys disconnectNamedPipe(pipe windows.Handle) (err error) = DisconnectNamedPipe
//sys getNamedPipeInfo(pipe windows.Handle, flags *uint32, outSize *uint32, inSize *uint32, maxInstances *uint32) (err error) = GetNamedPipeInfo
//sys getNamedPipeHandleState(pipe windows.Handle, state *uint32, curInstances *uint32, maxCollectionCount *uint32, collectDataTimeout *uint32, userName *uint16, maxUserNameSize uint32) (err error) = GetNamedPipeHandleStateW
//sys ntCreateNamedPipeFile(pipe *windows.Handle, access ntAccessMask, oa *objectAttributes, iosb *ioStatusBlock, share ntFileShareMode, disposition ntFileCreationDisposition, options ntFileOptions, typ uint32, readMode uint32, completionMode uint32, maxInstances uint32, inboundQuota uint32, outputQuota uint32, timeout *int64) (status ntStatus) = ntdll.NtCreateNamedPipeFile
//sys rtlNtStatusToDosError(status ntStatus) (winerr error) = ntdll.RtlNtStatusToDosErrorNoTeb
//sys rtlDosPathNameToNtPathName(name *uint16, ntName *unicodeString, filePart uintptr, reserved uintptr) (status ntStatus) = ntdll.RtlDosPathNameToNtPathName_U
//sys rtlDefaultNpAcl(dacl *uintptr) (status ntStatus) = ntdll.RtlDefaultNpAcl
type PipeConn interface {
net.Conn
Disconnect() error
Flush() error
}
// type aliases for mkwinsyscall code
type (
ntAccessMask = fs.AccessMask
ntFileShareMode = fs.FileShareMode
ntFileCreationDisposition = fs.NTFileCreationDisposition
ntFileOptions = fs.NTCreateOptions
)
type ioStatusBlock struct {
Status, Information uintptr
}
// typedef struct _OBJECT_ATTRIBUTES {
// ULONG Length;
// HANDLE RootDirectory;
// PUNICODE_STRING ObjectName;
// ULONG Attributes;
// PVOID SecurityDescriptor;
// PVOID SecurityQualityOfService;
// } OBJECT_ATTRIBUTES;
//
// https://learn.microsoft.com/en-us/windows/win32/api/ntdef/ns-ntdef-_object_attributes
type objectAttributes struct {
Length uintptr
RootDirectory uintptr
ObjectName *unicodeString
Attributes uintptr
SecurityDescriptor *securityDescriptor
SecurityQoS uintptr
}
type unicodeString struct {
Length uint16
MaximumLength uint16
Buffer uintptr
}
// typedef struct _SECURITY_DESCRIPTOR {
// BYTE Revision;
// BYTE Sbz1;
// SECURITY_DESCRIPTOR_CONTROL Control;
// PSID Owner;
// PSID Group;
// PACL Sacl;
// PACL Dacl;
// } SECURITY_DESCRIPTOR, *PISECURITY_DESCRIPTOR;
//
// https://learn.microsoft.com/en-us/windows/win32/api/winnt/ns-winnt-security_descriptor
type securityDescriptor struct {
Revision byte
Sbz1 byte
Control uint16
Owner uintptr
Group uintptr
Sacl uintptr //revive:disable-line:var-naming SACL, not Sacl
Dacl uintptr //revive:disable-line:var-naming DACL, not Dacl
}
type ntStatus int32
func (status ntStatus) Err() error {
if status >= 0 {
return nil
}
return rtlNtStatusToDosError(status)
}
var (
// ErrPipeListenerClosed is returned for pipe operations on listeners that have been closed.
ErrPipeListenerClosed = net.ErrClosed
errPipeWriteClosed = errors.New("pipe has been closed for write")
)
type win32Pipe struct {
*win32File
path string
}
var _ PipeConn = (*win32Pipe)(nil)
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 {
if err := f.SetReadDeadline(t); err != nil {
return err
}
return f.SetWriteDeadline(t)
}
func (f *win32Pipe) Disconnect() error {
return disconnectNamedPipe(f.win32File.handle)
}
// 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.Flush()
if err != nil {
return err
}
_, 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 { //nolint:errorlint
// 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
} else if err == windows.ERROR_MORE_DATA { //nolint:errorlint // err is Errno
// ERROR_MORE_DATA indicates that the pipe's read mode is message mode
// and the message still has more bytes. Treat this as a success, since
// this package presents all named pipes as byte streams.
err = nil
}
return n, err
}
func (pipeAddress) Network() string {
return "pipe"
}
func (s pipeAddress) String() string {
return string(s)
}
// tryDialPipe attempts to dial the pipe at `path` until `ctx` cancellation or timeout.
func tryDialPipe(ctx context.Context, path *string, access fs.AccessMask, impLevel PipeImpLevel) (windows.Handle, error) {
for {
select {
case <-ctx.Done():
return windows.Handle(0), ctx.Err()
default:
h, err := fs.CreateFile(*path,
access,
0, // mode
nil, // security attributes
fs.OPEN_EXISTING,
fs.FILE_FLAG_OVERLAPPED|fs.SECURITY_SQOS_PRESENT|fs.FileSQSFlag(impLevel),
0, // template file handle
)
if err == nil {
return h, nil
}
if err != windows.ERROR_PIPE_BUSY { //nolint:errorlint // err is Errno
return h, &os.PathError{Err: err, Op: "open", Path: *path}
}
// Wait 10 msec and try again. This is a rather simplistic
// view, as we always try each 10 milliseconds.
time.Sleep(10 * time.Millisecond)
}
}
}
// DialPipe connects to a named pipe by path, timing out if the connection
// takes longer than the specified duration. If timeout is nil, then we use
// a default timeout of 2 seconds. (We do not use WaitNamedPipe.)
func DialPipe(path string, timeout *time.Duration) (net.Conn, error) {
var absTimeout time.Time
if timeout != nil {
absTimeout = time.Now().Add(*timeout)
} else {
absTimeout = time.Now().Add(2 * time.Second)
}
ctx, cancel := context.WithDeadline(context.Background(), absTimeout)
defer cancel()
conn, err := DialPipeContext(ctx, path)
if errors.Is(err, context.DeadlineExceeded) {
return nil, ErrTimeout
}
return conn, err
}
// DialPipeContext attempts to connect to a named pipe by `path` until `ctx`
// cancellation or timeout.
func DialPipeContext(ctx context.Context, path string) (net.Conn, error) {
return DialPipeAccess(ctx, path, uint32(fs.GENERIC_READ|fs.GENERIC_WRITE))
}
// PipeImpLevel is an enumeration of impersonation levels that may be set
// when calling DialPipeAccessImpersonation.
type PipeImpLevel uint32
const (
PipeImpLevelAnonymous = PipeImpLevel(fs.SECURITY_ANONYMOUS)
PipeImpLevelIdentification = PipeImpLevel(fs.SECURITY_IDENTIFICATION)
PipeImpLevelImpersonation = PipeImpLevel(fs.SECURITY_IMPERSONATION)
PipeImpLevelDelegation = PipeImpLevel(fs.SECURITY_DELEGATION)
)
// DialPipeAccess attempts to connect to a named pipe by `path` with `access` until `ctx`
// cancellation or timeout.
func DialPipeAccess(ctx context.Context, path string, access uint32) (net.Conn, error) {
return DialPipeAccessImpLevel(ctx, path, access, PipeImpLevelAnonymous)
}
// DialPipeAccessImpLevel attempts to connect to a named pipe by `path` with
// `access` at `impLevel` until `ctx` cancellation or timeout. The other
// DialPipe* implementations use PipeImpLevelAnonymous.
func DialPipeAccessImpLevel(ctx context.Context, path string, access uint32, impLevel PipeImpLevel) (net.Conn, error) {
var err error
var h windows.Handle
h, err = tryDialPipe(ctx, &path, fs.AccessMask(access), impLevel)
if err != nil {
return nil, err
}
var flags uint32
err = getNamedPipeInfo(h, &flags, nil, nil, nil)
if err != nil {
return nil, err
}
f, err := makeWin32File(h)
if err != nil {
windows.Close(h)
return nil, err
}
// If the pipe is in message mode, return a message byte pipe, which
// supports CloseWrite().
if flags&windows.PIPE_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 windows.Handle
path string
config PipeConfig
acceptCh chan (chan acceptResponse)
closeCh chan int
doneCh chan int
}
func makeServerPipeHandle(path string, sd []byte, c *PipeConfig, first bool) (windows.Handle, error) {
path16, err := windows.UTF16FromString(path)
if err != nil {
return 0, &os.PathError{Op: "open", Path: path, Err: err}
}
var oa objectAttributes
oa.Length = unsafe.Sizeof(oa)
var ntPath unicodeString
if err := rtlDosPathNameToNtPathName(&path16[0],
&ntPath,
0,
0,
).Err(); err != nil {
return 0, &os.PathError{Op: "open", Path: path, Err: err}
}
defer windows.LocalFree(windows.Handle(ntPath.Buffer)) //nolint:errcheck
oa.ObjectName = &ntPath
oa.Attributes = windows.OBJ_CASE_INSENSITIVE
// The security descriptor is only needed for the first pipe.
if first {
if sd != nil {
//todo: does `sdb` need to be allocated on the heap, or can go allocate it?
l := uint32(len(sd))
sdb, err := windows.LocalAlloc(0, l)
if err != nil {
return 0, fmt.Errorf("LocalAlloc for security descriptor with of length %d: %w", l, err)
}
defer windows.LocalFree(windows.Handle(sdb)) //nolint:errcheck
copy((*[0xffff]byte)(unsafe.Pointer(sdb))[:], sd)
oa.SecurityDescriptor = (*securityDescriptor)(unsafe.Pointer(sdb))
} else {
// Construct the default named pipe security descriptor.
var dacl uintptr
if err := rtlDefaultNpAcl(&dacl).Err(); err != nil {
return 0, fmt.Errorf("getting default named pipe ACL: %w", err)
}
defer windows.LocalFree(windows.Handle(dacl)) //nolint:errcheck
sdb := &securityDescriptor{
Revision: 1,
Control: windows.SE_DACL_PRESENT,
Dacl: dacl,
}
oa.SecurityDescriptor = sdb
}
}
typ := uint32(windows.FILE_PIPE_REJECT_REMOTE_CLIENTS)
if c.MessageMode {
typ |= windows.FILE_PIPE_MESSAGE_TYPE
}
disposition := fs.FILE_OPEN
access := fs.GENERIC_READ | fs.GENERIC_WRITE | fs.SYNCHRONIZE
if first {
disposition = fs.FILE_CREATE
// By not asking for read or write access, the named pipe file system
// will put this pipe into an initially disconnected state, blocking
// client connections until the next call with first == false.
access = fs.SYNCHRONIZE
}
timeout := int64(-50 * 10000) // 50ms
var (
h windows.Handle
iosb ioStatusBlock
)
err = ntCreateNamedPipeFile(&h,
access,
&oa,
&iosb,
fs.FILE_SHARE_READ|fs.FILE_SHARE_WRITE,
disposition,
0,
typ,
0,
0,
0xffffffff,
uint32(c.InputBufferSize),
uint32(c.OutputBufferSize),
&timeout).Err()
if err != nil {
return 0, &os.PathError{Op: "open", Path: path, Err: err}
}
runtime.KeepAlive(ntPath)
return h, nil
}
func (l *win32PipeListener) makeServerPipe() (*win32File, error) {
h, err := makeServerPipeHandle(l.path, nil, &l.config, false)
if err != nil {
return nil, err
}
f, err := makeWin32File(h)
if err != nil {
windows.Close(h)
return nil, err
}
return f, nil
}
func (l *win32PipeListener) makeConnectedServerPipe() (*win32File, error) {
p, err := l.makeServerPipe()
if err != nil {
return nil, err
}
// Wait for the client to connect.
ch := make(chan error)
go func(p *win32File) {
ch <- connectPipe(p)
}(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 { //nolint:errorlint // err is Errno
err = ErrPipeListenerClosed
}
}
return p, err
}
func (l *win32PipeListener) listenerRoutine() {
closed := false
for !closed {
select {
case <-l.closeCh:
closed = true
case responseCh := <-l.acceptCh:
var (
p *win32File
err error
)
for {
p, err = l.makeConnectedServerPipe()
// If the connection was immediately closed by the client, try
// again.
if err != windows.ERROR_NO_DATA { //nolint:errorlint // err is Errno
break
}
}
responseCh <- acceptResponse{p, err}
closed = err == ErrPipeListenerClosed //nolint:errorlint // err is Errno
}
}
windows.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 of the input buffer, in bytes.
InputBufferSize int32
// OutputBufferSize specifies the size of the output 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
}
l := &win32PipeListener{
firstHandle: h,
path: path,
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
}
defer p.wg.Done()
err = connectNamedPipe(p.handle, &c.o)
_, err = p.asyncIO(c, nil, 0, err)
if err != nil && err != windows.ERROR_PIPE_CONNECTED { //nolint:errorlint // err is Errno
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)
}
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