/
losetup.go
138 lines (122 loc) · 2.7 KB
/
losetup.go
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package golosetup
import (
"bytes"
"fmt"
"os/exec"
"strings"
)
const (
LOSETUP_COMMAND = "losetup"
)
type Command struct {
Path string
Args []string
stdout *bytes.Buffer
stderr *bytes.Buffer
}
func NewCommand(path string, args ...string) *Command {
return &Command{
Path: path,
Args: args,
stdout: &bytes.Buffer{},
stderr: &bytes.Buffer{},
}
}
func (cmd *Command) AddArgs(args ...string) *Command {
cmd.Args = append(cmd.Args, args...)
return cmd
}
func (cmd *Command) Run() (*Command, error) {
ecmd := exec.Command(cmd.Path, cmd.Args...)
ecmd.Stdout = cmd.stdout
ecmd.Stderr = cmd.stderr
err := ecmd.Run()
if err != nil {
err = fmt.Errorf("%v: %s", err, cmd.ErrOutput())
}
return cmd, err
}
func (cmd *Command) Output() string {
return cmd.stdout.String()
}
func (cmd *Command) ErrOutput() string {
return cmd.stderr.String()
}
type LosetupCommand struct {
*Command
}
func NewLosetupCommand() *LosetupCommand {
return &LosetupCommand{
Command: NewCommand(LOSETUP_COMMAND),
}
}
func ListDevices() (*Devices, error) {
cmd, err := NewLosetupCommand().AddArgs("-l", "-O", "NAME,BACK-FILE,SIZELIMIT,RO").Run()
if err != nil {
return nil, err
}
output := cmd.Output()
devs, err := parseDevices(output)
return devs, err
}
func GetUnusedDevice() (string, error) {
// find first unused device
cmd, err := NewLosetupCommand().AddArgs("-f").Run()
if err != nil {
return "", err
}
return strings.TrimSuffix(cmd.Output(), "\n"), nil
}
func AttachDevice(filePath string, partScan bool) (*Device, error) {
oldDevs, err := ListDevices()
if err != nil {
return nil, err
}
oldDev := oldDevs.GetDeviceByFile(filePath)
if oldDev != nil {
//return nil, fmt.Errorf("file %q already attached to %q, attached twice???", oldDev.BackFile, oldDev.Name)
return oldDev, nil
}
args := []string{}
if partScan {
args = append(args, "-P")
}
args = append(args, []string{"-f", filePath}...)
_, err = NewLosetupCommand().AddArgs(args...).Run()
if err != nil {
return nil, err
}
devs, err := ListDevices()
if err != nil {
return nil, err
}
dev := devs.GetDeviceByFile(filePath)
if dev == nil {
return nil, fmt.Errorf("Not found loop device by file: %s", filePath)
}
return dev, nil
}
func DetachDevice(devPath string) error {
devs, err := ListDevices()
if err != nil {
return err
}
dev := devs.GetDeviceByName(devPath)
if dev == nil {
return nil
}
_, err = NewLosetupCommand().AddArgs("-d", dev.Name).Run()
return err
}
func DetachDeviceByFile(filePath string) error {
devs, err := ListDevices()
if err != nil {
return err
}
dev := devs.GetDeviceByFile(filePath)
if dev == nil {
return nil
}
_, err = NewLosetupCommand().AddArgs("-d", dev.Name).Run()
return err
}