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
|
package uevent
import (
"context"
"errors"
"io/fs"
"log"
"os"
"path/filepath"
)
// synthAdd is prepared bytes written to uevent to cause a synthetic add event
// to be emitted during coldboot.
var synthAdd = []byte(KOBJ_ADD.String())
// Coldboot writes "add" to every uevent file that it finds in /sys/devices.
// This causes the kernel to regenerate the uevents for these paths.
//
// The specified pathname must present the sysfs root.
//
// Note that while [AOSP documentation] claims to also scan /sys/class and
// /sys/block, this is no longer the case, and the documentation was not updated
// when this changed.
//
// [AOSP documentation]: https://android.googlesource.com/platform/system/core/+/master/init/README.ueventd.md
func Coldboot(
ctx context.Context,
pathname string,
visited chan<- string,
handleWalkErr func(error) error,
) error {
if handleWalkErr == nil {
handleWalkErr = func(err error) error {
if errors.Is(err, fs.ErrNotExist) {
log.Println("coldboot", err)
return nil
}
return err
}
}
return filepath.WalkDir(filepath.Join(pathname, "devices"), func(
path string,
d fs.DirEntry,
err error,
) error {
if err != nil {
return handleWalkErr(err)
}
if err = ctx.Err(); err != nil {
return err
}
if d.IsDir() || d.Name() != "uevent" {
return nil
}
if err = os.WriteFile(path, synthAdd, 0); err != nil {
return handleWalkErr(err)
}
select {
case visited <- path:
break
case <-ctx.Done():
return ctx.Err()
}
return nil
})
}
|
