moby/pkg/pidfile/pidfile.go
John Starks 9e5b93565c Windows: don't overwrite PID file if process exists
pidfile.New() was opening a file in /proc to determine if the owning
process still exists. Use syscall.OpenProcess() on Windows instead.

Other OSes may also need to be updated here.

Signed-off-by: John Starks <jostarks@microsoft.com>
2016-04-18 16:41:37 -07:00

49 lines
1.2 KiB
Go

// Package pidfile provides structure and helper functions to create and remove
// PID file. A PID file is usually a file used to store the process ID of a
// running process.
package pidfile
import (
"fmt"
"io/ioutil"
"os"
"strconv"
"strings"
)
// PIDFile is a file used to store the process ID of a running process.
type PIDFile struct {
path string
}
func checkPIDFileAlreadyExists(path string) error {
if pidByte, err := ioutil.ReadFile(path); err == nil {
pidString := strings.TrimSpace(string(pidByte))
if pid, err := strconv.Atoi(pidString); err == nil {
if processExists(pid) {
return fmt.Errorf("pid file found, ensure docker is not running or delete %s", path)
}
}
}
return nil
}
// New creates a PIDfile using the specified path.
func New(path string) (*PIDFile, error) {
if err := checkPIDFileAlreadyExists(path); err != nil {
return nil, err
}
if err := ioutil.WriteFile(path, []byte(fmt.Sprintf("%d", os.Getpid())), 0644); err != nil {
return nil, err
}
return &PIDFile{path: path}, nil
}
// Remove removes the PIDFile.
func (file PIDFile) Remove() error {
if err := os.Remove(file.path); err != nil {
return err
}
return nil
}