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// Copyright 2015 CNI authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package disk
import (
"fmt"
"io/ioutil"
"net"
"os"
"path/filepath"
"strings"
"github.com/containernetworking/cni/plugins/ipam/host-local/backend"
)
const lastIPFile = "last_reserved_ip"
var defaultDataDir = "/var/lib/cni/networks"
type Store struct {
FileLock
dataDir string
}
// Store implements the Store interface
var _ backend.Store = &Store{}
func New(network, dataDir string) (*Store, error) {
if dataDir == "" {
dataDir = defaultDataDir
}
dir := filepath.Join(dataDir, network)
if err := os.MkdirAll(dir, 0644); err != nil {
return nil, err
}
lk, err := NewFileLock(dir)
if err != nil {
return nil, err
}
return &Store{*lk, dir}, nil
}
func (s *Store) Reserve(id string, ip net.IP) (bool, error) {
fname := filepath.Join(s.dataDir, ip.String())
f, err := os.OpenFile(fname, os.O_RDWR|os.O_EXCL|os.O_CREATE, 0644)
if os.IsExist(err) {
return false, nil
}
if err != nil {
return false, err
}
if _, err := f.WriteString(strings.TrimSpace(id)); err != nil {
f.Close()
os.Remove(f.Name())
return false, err
}
if err := f.Close(); err != nil {
os.Remove(f.Name())
return false, err
}
// store the reserved ip in lastIPFile
ipfile := filepath.Join(s.dataDir, lastIPFile)
err = ioutil.WriteFile(ipfile, []byte(ip.String()), 0644)
if err != nil {
return false, err
}
return true, nil
}
// LastReservedIP returns the last reserved IP if exists
func (s *Store) LastReservedIP() (net.IP, error) {
ipfile := filepath.Join(s.dataDir, lastIPFile)
data, err := ioutil.ReadFile(ipfile)
if err != nil {
return nil, fmt.Errorf("Failed to retrieve last reserved ip: %v", err)
}
return net.ParseIP(string(data)), nil
}
func (s *Store) Release(ip net.IP) error {
return os.Remove(filepath.Join(s.dataDir, ip.String()))
}
// N.B. This function eats errors to be tolerant and
// release as much as possible
func (s *Store) ReleaseByID(id string) error {
err := filepath.Walk(s.dataDir, func(path string, info os.FileInfo, err error) error {
if err != nil || info.IsDir() {
return nil
}
data, err := ioutil.ReadFile(path)
if err != nil {
return nil
}
if strings.TrimSpace(string(data)) == strings.TrimSpace(id) {
if err := os.Remove(path); err != nil {
return nil
}
}
return nil
})
return err
}
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