1 // Copyright 2011 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
13 // maxSendfileSize is the largest chunk size we ask the kernel to copy
15 const maxSendfileSize int = 4 << 20
17 // sendFile copies the contents of r to c using the sendfile
18 // system call to minimize copies.
20 // if handled == true, sendFile returns the number of bytes copied and any
23 // if handled == false, sendFile performed no work.
24 func sendFile(c *netFD, r io.Reader) (written int64, err error, handled bool) {
25 var remain int64 = 1 << 62 // by default, copy until EOF
27 lr, ok := r.(*io.LimitedReader)
29 remain, r = lr.N, lr.R
41 if err := c.incref(false); err != nil {
50 if int64(n) > remain {
53 n, err1 := syscall.Sendfile(dst, src, nil, n)
58 if n == 0 && err1 == nil {
61 if err1 == syscall.EAGAIN && c.wdeadline >= 0 {
62 if err1 = pollserver.WaitWrite(c); err1 == nil {
67 // This includes syscall.ENOSYS (no kernel
68 // support) and syscall.EINVAL (fd types which
69 // don't implement sendfile together)
70 err = &OpError{"sendfile", c.net, c.raddr, err1}
77 return written, err, written > 0