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
|
// Copyright 2016 the Go-FUSE Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package splice
import (
"fmt"
"log"
"os"
"syscall"
)
func (p *Pair) LoadFromAt(fd uintptr, sz int, off int64) (int, error) {
n, err := syscall.Splice(int(fd), &off, p.w, nil, sz, 0)
return int(n), err
}
func (p *Pair) LoadFrom(fd uintptr, sz int) (int, error) {
if sz > p.size {
return 0, fmt.Errorf("LoadFrom: not enough space %d, %d",
sz, p.size)
}
n, err := syscall.Splice(int(fd), nil, p.w, nil, sz, 0)
if err != nil {
err = os.NewSyscallError("Splice load from", err)
}
return int(n), err
}
func (p *Pair) WriteTo(fd uintptr, n int) (int, error) {
m, err := syscall.Splice(p.r, nil, int(fd), nil, int(n), 0)
if err != nil {
err = os.NewSyscallError("Splice write", err)
}
return int(m), err
}
const _SPLICE_F_NONBLOCK = 0x2
func (p *Pair) discard() {
_, err := syscall.Splice(p.r, nil, int(devNullFD), nil, int(p.size), _SPLICE_F_NONBLOCK)
if err == syscall.EAGAIN {
// all good.
} else if err != nil {
errR := syscall.Close(p.r)
errW := syscall.Close(p.w)
// This can happen if something closed our fd
// inadvertently (eg. double close)
log.Panicf("splicing into /dev/null: %v (close R %d '%v', close W %d '%v')", err, p.r, errR, p.w, errW)
}
}
|
