talos/internal/app/udevd/main.go
2018-12-19 22:22:05 -08:00

118 lines
2.7 KiB
Go

// Package udevd is a library for working with uevent messages from the netlink
// socket.
package main
import (
"fmt"
"log"
"os"
"path"
"github.com/autonomy/talos/internal/app/udevd/internal/drivers/scsi"
"github.com/autonomy/talos/internal/app/udevd/internal/uevent"
"github.com/pkg/errors"
)
func init() {
log.SetFlags(log.Lshortfile | log.Ldate | log.Lmicroseconds | log.Ltime)
}
func watch() error {
k, err := uevent.Dial()
if err != nil {
return err
}
// nolint: errcheck
defer k.Close()
for u := range k.Watch() {
if u.Error != nil {
log.Printf("uevent error: %+v\n", err)
continue
}
if err := handle(u.Message); err != nil {
log.Printf("event handler error: %+v\n", err)
}
}
return nil
}
// nolint: gocyclo
func handle(message *uevent.Message) (err error) {
if message.Subsystem == uevent.SubsystemBlock {
var devname, devtype, partn string
var ok bool
if devname, ok = message.Values["DEVNAME"]; !ok {
return errors.Errorf("DEVNAME not found\n")
}
devpath := path.Join("/dev", devname)
devtype = message.Values["DEVTYPE"]
var device *scsi.Device
if device, err = scsi.NewDevice(devpath); err != nil {
return errors.Errorf("error opening %s: %+v\n", devpath, err)
}
// nolint: errcheck
defer device.Close()
if err = device.Identify(); err != nil {
return errors.Errorf("error identifying %s: %+v\n", devpath, err)
}
if device.WWN == "" {
log.Printf("no wwn found for %s\n", devpath)
return nil
}
oldname := fmt.Sprintf("../../%s", devname)
newname := fmt.Sprintf("/dev/disk/by-id/wwn-%s", device.WWN)
if partn, ok = message.Values["PARTN"]; ok && devtype == "partition" {
newname += "-part" + partn
}
switch message.Action {
case uevent.ActionAdd:
log.Printf("creating symlink %s -> %s\n", newname, oldname)
if _, err = os.Lstat(newname); err == nil {
if err = os.Remove(newname); err != nil {
log.Printf("failed to remove symlink: %v\n", err)
}
}
if err = os.Symlink(oldname, newname); err != nil {
return errors.Errorf("failed to create symlink %s: %+v", newname, err)
}
case uevent.ActionRemove:
log.Printf("removing symlink %s -> %s\n", newname, oldname)
if _, err = os.Lstat(newname); err == nil {
if err = os.Remove(newname); err != nil {
log.Printf("failed to remove symlink: %v\n", err)
}
}
default:
log.Printf("unhandled action %q on %s", message.Action, devname)
}
}
return nil
}
func main() {
if err := os.MkdirAll("/dev/disk/by-id", os.ModeDir); err != nil && !os.IsExist(err) {
log.Printf("failed to create directoy /dev/disk/by-id: %+v\n", err)
os.Exit(1)
}
if err := watch(); err != nil {
log.Printf("failed watch uevents: %+v\n", err)
os.Exit(1)
}
}