-
Notifications
You must be signed in to change notification settings - Fork 17.4k
/
sendfile_bsd.go
62 lines (55 loc) · 1.68 KB
/
sendfile_bsd.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build darwin || dragonfly || freebsd
package poll
import "syscall"
// maxSendfileSize is the largest chunk size we ask the kernel to copy
// at a time.
// sendfile(2)s on *BSD and Darwin don't have a limit on the size of
// data to copy at a time, we pick the typical SSIZE_MAX on 32-bit systems,
// which ought to be sufficient for all practical purposes.
const maxSendfileSize int = 1<<31 - 1
// SendFile wraps the sendfile system call.
func SendFile(dstFD *FD, src int, pos, remain int64) (written int64, err error, handled bool) {
defer func() {
TestHookDidSendFile(dstFD, src, written, err, handled)
}()
if err := dstFD.writeLock(); err != nil {
return 0, err, false
}
defer dstFD.writeUnlock()
if err := dstFD.pd.prepareWrite(dstFD.isFile); err != nil {
return 0, err, false
}
dst := dstFD.Sysfd
for remain > 0 {
n := maxSendfileSize
if int64(n) > remain {
n = int(remain)
}
pos1 := pos
n, err = syscall.Sendfile(dst, src, &pos1, n)
if n > 0 {
pos += int64(n)
written += int64(n)
remain -= int64(n)
}
if err == syscall.EINTR {
continue
}
// This includes syscall.ENOSYS (no kernel
// support) and syscall.EINVAL (fd types which
// don't implement sendfile), and other errors.
// We should end the loop when there is no error
// returned from sendfile(2) or it is not a retryable error.
if err != syscall.EAGAIN {
break
}
if err = dstFD.pd.waitWrite(dstFD.isFile); err != nil {
break
}
}
handled = written != 0 || (err != syscall.ENOSYS && err != syscall.EINVAL)
return
}