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
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
|
package main
import (
"fmt"
"path/filepath"
"syscall"
)
// SYS_COPY_FILE_RANGE on x86_64 Linux.
const sysCopyFileRange = 326
// copyFileRangeBasic copies bytes from a source file to a destination file
// using copy_file_range(2) with flags=0 as required by the manpage.
func copyFileRangeBasic() error {
dir, cleanup, err := makeTempDir("copy-file-range-basic")
if err != nil {
return err
}
defer cleanup()
srcPath := filepath.Join(dir, "copyrangesrc.txt")
dstPath := filepath.Join(dir, "copyrangedst.txt")
srcFd, err := syscall.Open(srcPath, syscall.O_RDWR|syscall.O_CREAT|syscall.O_TRUNC, 0o644)
if err != nil {
return fmt.Errorf("open source: %w", err)
}
defer syscall.Close(srcFd)
dstFd, err := syscall.Open(dstPath, syscall.O_RDWR|syscall.O_CREAT|syscall.O_TRUNC, 0o644)
if err != nil {
return fmt.Errorf("open destination: %w", err)
}
defer syscall.Close(dstFd)
data := []byte("copy_file_range integration data")
if _, err := syscall.Write(srcFd, data); err != nil {
return fmt.Errorf("write source: %w", err)
}
if _, err := syscall.Seek(srcFd, 0, 0); err != nil {
return fmt.Errorf("seek source: %w", err)
}
n, _, errno := syscall.Syscall6(uintptr(sysCopyFileRange), uintptr(srcFd), 0, uintptr(dstFd), 0, uintptr(len(data)), 0)
if errno != 0 {
return fmt.Errorf("copy_file_range: %w", errno)
}
if n == 0 {
return fmt.Errorf("copy_file_range copied 0 bytes")
}
return nil
}
// copyFileRangeBadDstFd calls copy_file_range(2) with an invalid destination fd.
// The syscall should fail with EBADF, while still emitting the enter tracepoint.
func copyFileRangeBadDstFd() error {
dir, cleanup, err := makeTempDir("copy-file-range-bad-dst")
if err != nil {
return err
}
defer cleanup()
srcPath := filepath.Join(dir, "copyrangeebadfsrc.txt")
srcFd, err := syscall.Open(srcPath, syscall.O_RDWR|syscall.O_CREAT|syscall.O_TRUNC, 0o644)
if err != nil {
return fmt.Errorf("open source: %w", err)
}
defer syscall.Close(srcFd)
if _, err := syscall.Write(srcFd, []byte("copy_file_range ebadf data")); err != nil {
return fmt.Errorf("write source: %w", err)
}
_, _, errno := syscall.Syscall6(uintptr(sysCopyFileRange), uintptr(srcFd), 0, uintptr(99999), 0, uintptr(16), 0)
if errno != syscall.EBADF {
return fmt.Errorf("expected EBADF from copy_file_range with invalid dst fd, got %v", errno)
}
return nil
}
|
