)
// SendFile wraps the TransmitFile call.
-func SendFile(fd *FD, src syscall.Handle, n int64) (written int64, err error) {
+func SendFile(fd *FD, src syscall.Handle, size int64) (written int64, err error, handled bool) {
defer func() {
TestHookDidSendFile(fd, 0, written, err, written > 0)
}()
if fd.kind == kindPipe {
// TransmitFile does not work with pipes
- return 0, syscall.ESPIPE
+ return 0, syscall.ESPIPE, false
}
if ft, _ := syscall.GetFileType(src); ft == syscall.FILE_TYPE_PIPE {
- return 0, syscall.ESPIPE
+ return 0, syscall.ESPIPE, false
}
if err := fd.writeLock(); err != nil {
- return 0, err
+ return 0, err, false
}
defer fd.writeUnlock()
- o := &fd.wop
- o.handle = src
-
- // TODO(brainman): skip calling syscall.Seek if OS allows it
- curpos, err := syscall.Seek(o.handle, 0, io.SeekCurrent)
+ // Get the file size so we don't read past the end of the file.
+ var fi syscall.ByHandleFileInformation
+ if err := syscall.GetFileInformationByHandle(src, &fi); err != nil {
+ return 0, err, false
+ }
+ fileSize := int64(fi.FileSizeHigh)<<32 + int64(fi.FileSizeLow)
+ startpos, err := syscall.Seek(src, 0, io.SeekCurrent)
if err != nil {
- return 0, err
+ return 0, err, false
+ }
+ maxSize := fileSize - startpos
+ if size <= 0 {
+ size = maxSize
+ } else {
+ size = min(size, maxSize)
}
- if n <= 0 { // We don't know the size of the file so infer it.
- // Find the number of bytes offset from curpos until the end of the file.
- n, err = syscall.Seek(o.handle, -curpos, io.SeekEnd)
- if err != nil {
- return
- }
- // Now seek back to the original position.
- if _, err = syscall.Seek(o.handle, curpos, io.SeekStart); err != nil {
- return
+ defer func() {
+ if written > 0 {
+ // Some versions of Windows (Windows 10 1803) do not set
+ // file position after TransmitFile completes.
+ // So just use Seek to set file position.
+ _, serr := syscall.Seek(src, startpos+written, io.SeekStart)
+ if err != nil {
+ err = serr
+ }
}
- }
+ }()
// TransmitFile can be invoked in one call with at most
// 2,147,483,646 bytes: the maximum value for a 32-bit integer minus 1.
// See https://docs.microsoft.com/en-us/windows/win32/api/mswsock/nf-mswsock-transmitfile
const maxChunkSizePerCall = int64(0x7fffffff - 1)
- for n > 0 {
+ o := &fd.wop
+ o.handle = src
+ for size > 0 {
chunkSize := maxChunkSizePerCall
- if chunkSize > n {
- chunkSize = n
+ if chunkSize > size {
+ chunkSize = size
}
- o.o.Offset = uint32(curpos)
- o.o.OffsetHigh = uint32(curpos >> 32)
+ off := startpos + written
+ o.o.Offset = uint32(off)
+ o.o.OffsetHigh = uint32(off >> 32)
- nw, err := execIO(o, func(o *operation) error {
+ n, err := execIO(o, func(o *operation) error {
o.qty = uint32(chunkSize)
return syscall.TransmitFile(o.fd.Sysfd, o.handle, o.qty, 0, &o.o, nil, syscall.TF_WRITE_BEHIND)
})
if err != nil {
- return written, err
- }
-
- curpos += int64(nw)
-
- // Some versions of Windows (Windows 10 1803) do not set
- // file position after TransmitFile completes.
- // So just use Seek to set file position.
- if _, err = syscall.Seek(o.handle, curpos, io.SeekStart); err != nil {
- return written, err
+ return written, err, written > 0
}
- n -= int64(nw)
- written += int64(nw)
+ size -= int64(n)
+ written += int64(n)
}
- return
+ return written, nil, written > 0
}
// Return file data using io.Copy, which should use
// sendFile if available.
var sbytes int64
- switch runtime.GOOS {
- case "windows":
- // Windows is not using sendfile for some reason:
- // https://go.dev/issue/67042
- sbytes, err = io.Copy(conn, f)
- default:
- expectSendfile(t, conn, func() {
- if limit > 0 {
- sbytes, err = io.CopyN(conn, f, limit)
- if err == io.EOF && limit > size {
- err = nil
- }
- } else {
- sbytes, err = io.Copy(conn, f)
+ expectSendfile(t, conn, func() {
+ if limit > 0 {
+ sbytes, err = io.CopyN(conn, f, limit)
+ if err == io.EOF && limit > size {
+ err = nil
}
- })
- }
+ } else {
+ sbytes, err = io.Copy(conn, f)
+ }
+ })
if err != nil {
errc <- err
return
import (
"internal/poll"
"io"
- "os"
"syscall"
)
const supportsSendfile = true
-// sendFile copies the contents of r to c using the TransmitFile
+// TODO: deduplicate this file with sendfile_linux.go and sendfile_unix_alt.go.
+
+// sendFile copies the contents of r to c using the sendfile
// system call to minimize copies.
//
-// if handled == true, sendFile returns the number of bytes copied and any
-// non-EOF error.
+// if handled == true, sendFile returns the number (potentially zero) of bytes
+// copied and any non-EOF error.
//
// if handled == false, sendFile performed no work.
-func sendFile(fd *netFD, r io.Reader) (written int64, err error, handled bool) {
- var n int64 = 0 // by default, copy until EOF.
+func sendFile(c *netFD, r io.Reader) (written int64, err error, handled bool) {
+ var remain int64 = 0 // by default, copy until EOF.
lr, ok := r.(*io.LimitedReader)
if ok {
- n, r = lr.N, lr.R
- if n <= 0 {
+ remain, r = lr.N, lr.R
+ if remain <= 0 {
return 0, nil, true
}
}
- f, ok := r.(*os.File)
+ // r might be an *os.File or an os.fileWithoutWriteTo.
+ // Type assert to an interface rather than *os.File directly to handle the latter case.
+ f, ok := r.(syscall.Conn)
if !ok {
return 0, nil, false
}
- written, err = poll.SendFile(&fd.pfd, syscall.Handle(f.Fd()), n)
+ sc, err := f.SyscallConn()
if err != nil {
- err = wrapSyscallError("transmitfile", err)
+ return 0, nil, false
}
- // If any byte was copied, regardless of any error
- // encountered mid-way, handled must be set to true.
- handled = written > 0
+ var werr error
+ err = sc.Read(func(fd uintptr) bool {
+ written, werr, handled = poll.SendFile(&c.pfd, syscall.Handle(fd), remain)
+ return true
+ })
+ if err == nil {
+ err = werr
+ }
+
+ if lr != nil {
+ lr.N = remain - written
+ }
- return
+ return written, wrapSyscallError("sendfile", err), handled
}