gtsocial-umbx

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devices.go (2109B)

      1 /*
      2    Copyright The containerd Authors.
      3 
      4    Licensed under the Apache License, Version 2.0 (the "License");
      5    you may not use this file except in compliance with the License.
      6    You may obtain a copy of the License at
      7 
      8        http://www.apache.org/licenses/LICENSE-2.0
      9 
     10    Unless required by applicable law or agreed to in writing, software
     11    distributed under the License is distributed on an "AS IS" BASIS,
     12    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13    See the License for the specific language governing permissions and
     14    limitations under the License.
     15 */
     16 
     17 package cgroup1
     18 
     19 import (
     20 	"fmt"
     21 	"os"
     22 	"path/filepath"
     23 
     24 	specs "github.com/opencontainers/runtime-spec/specs-go"
     25 )
     26 
     27 const (
     28 	allowDeviceFile = "devices.allow"
     29 	denyDeviceFile  = "devices.deny"
     30 	wildcard        = -1
     31 )
     32 
     33 func NewDevices(root string) *devicesController {
     34 	return &devicesController{
     35 		root: filepath.Join(root, string(Devices)),
     36 	}
     37 }
     38 
     39 type devicesController struct {
     40 	root string
     41 }
     42 
     43 func (d *devicesController) Name() Name {
     44 	return Devices
     45 }
     46 
     47 func (d *devicesController) Path(path string) string {
     48 	return filepath.Join(d.root, path)
     49 }
     50 
     51 func (d *devicesController) Create(path string, resources *specs.LinuxResources) error {
     52 	if err := os.MkdirAll(d.Path(path), defaultDirPerm); err != nil {
     53 		return err
     54 	}
     55 	for _, device := range resources.Devices {
     56 		file := denyDeviceFile
     57 		if device.Allow {
     58 			file = allowDeviceFile
     59 		}
     60 		if device.Type == "" {
     61 			device.Type = "a"
     62 		}
     63 		if err := os.WriteFile(
     64 			filepath.Join(d.Path(path), file),
     65 			[]byte(deviceString(device)),
     66 			defaultFilePerm,
     67 		); err != nil {
     68 			return err
     69 		}
     70 	}
     71 	return nil
     72 }
     73 
     74 func (d *devicesController) Update(path string, resources *specs.LinuxResources) error {
     75 	return d.Create(path, resources)
     76 }
     77 
     78 func deviceString(device specs.LinuxDeviceCgroup) string {
     79 	return fmt.Sprintf("%s %s:%s %s",
     80 		device.Type,
     81 		deviceNumber(device.Major),
     82 		deviceNumber(device.Minor),
     83 		device.Access,
     84 	)
     85 }
     86 
     87 func deviceNumber(number *int64) string {
     88 	if number == nil || *number == wildcard {
     89 		return "*"
     90 	}
     91 	return fmt.Sprint(*number)
     92 }