084c621c66
This also makes sure that devices are pointers to avoid copies Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
119 lines
3 KiB
Go
119 lines
3 KiB
Go
package devices
|
|
|
|
import (
|
|
"errors"
|
|
"fmt"
|
|
"io/ioutil"
|
|
"os"
|
|
"path/filepath"
|
|
"syscall"
|
|
)
|
|
|
|
const (
|
|
Wildcard = -1
|
|
)
|
|
|
|
var (
|
|
ErrNotADeviceNode = errors.New("not a device node")
|
|
)
|
|
|
|
type Device struct {
|
|
Type rune `json:"type,omitempty"`
|
|
Path string `json:"path,omitempty"` // It is fine if this is an empty string in the case that you are using Wildcards
|
|
MajorNumber int64 `json:"major_number,omitempty"` // Use the wildcard constant for wildcards.
|
|
MinorNumber int64 `json:"minor_number,omitempty"` // Use the wildcard constant for wildcards.
|
|
CgroupPermissions string `json:"cgroup_permissions,omitempty"` // Typically just "rwm"
|
|
FileMode os.FileMode `json:"file_mode,omitempty"` // The permission bits of the file's mode
|
|
}
|
|
|
|
func GetDeviceNumberString(deviceNumber int64) string {
|
|
if deviceNumber == Wildcard {
|
|
return "*"
|
|
} else {
|
|
return fmt.Sprintf("%d", deviceNumber)
|
|
}
|
|
}
|
|
|
|
func (device *Device) GetCgroupAllowString() string {
|
|
return fmt.Sprintf("%c %s:%s %s", device.Type, GetDeviceNumberString(device.MajorNumber), GetDeviceNumberString(device.MinorNumber), device.CgroupPermissions)
|
|
}
|
|
|
|
// Given the path to a device and it's cgroup_permissions(which cannot be easilly queried) look up the information about a linux device and return that information as a Device struct.
|
|
func GetDevice(path string, cgroupPermissions string) (*Device, error) {
|
|
fileInfo, err := os.Stat(path)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
var (
|
|
devType rune
|
|
mode = fileInfo.Mode()
|
|
fileModePermissionBits = os.FileMode.Perm(mode)
|
|
)
|
|
|
|
switch {
|
|
case mode&os.ModeDevice == 0:
|
|
return nil, ErrNotADeviceNode
|
|
case mode&os.ModeCharDevice != 0:
|
|
fileModePermissionBits |= syscall.S_IFCHR
|
|
devType = 'c'
|
|
default:
|
|
fileModePermissionBits |= syscall.S_IFBLK
|
|
devType = 'b'
|
|
}
|
|
|
|
stat_t, ok := fileInfo.Sys().(*syscall.Stat_t)
|
|
if !ok {
|
|
return nil, fmt.Errorf("cannot determine the device number for device %s", path)
|
|
}
|
|
devNumber := int(stat_t.Rdev)
|
|
|
|
return &Device{
|
|
Type: devType,
|
|
Path: path,
|
|
MajorNumber: Major(devNumber),
|
|
MinorNumber: Minor(devNumber),
|
|
CgroupPermissions: cgroupPermissions,
|
|
FileMode: fileModePermissionBits,
|
|
}, nil
|
|
}
|
|
|
|
func GetHostDeviceNodes() ([]*Device, error) {
|
|
return getDeviceNodes("/dev")
|
|
}
|
|
|
|
func getDeviceNodes(path string) ([]*Device, error) {
|
|
files, err := ioutil.ReadDir(path)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
out := []*Device{}
|
|
for _, f := range files {
|
|
if f.IsDir() {
|
|
switch f.Name() {
|
|
case "pts", "shm", "fd":
|
|
continue
|
|
default:
|
|
sub, err := getDeviceNodes(filepath.Join(path, f.Name()))
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
out = append(out, sub...)
|
|
continue
|
|
}
|
|
}
|
|
|
|
device, err := GetDevice(filepath.Join(path, f.Name()), "rwm")
|
|
if err != nil {
|
|
if err == ErrNotADeviceNode {
|
|
continue
|
|
}
|
|
return nil, err
|
|
}
|
|
out = append(out, device)
|
|
}
|
|
|
|
return out, nil
|
|
}
|