github.com/rkt/rkt@v1.30.1-0.20200224141603-171c416fac02/stage1/stop/stop.go (about)

     1  // Copyright 2016 The rkt Authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  //+build linux
    16  
    17  package main
    18  
    19  import (
    20  	"flag"
    21  	"fmt"
    22  	"io/ioutil"
    23  	"os"
    24  
    25  	"github.com/shirou/gopsutil/process"
    26  )
    27  
    28  var (
    29  	force bool
    30  )
    31  
    32  func init() {
    33  	flag.BoolVar(&force, "force", false, "Forced stopping")
    34  }
    35  
    36  func readIntFromFile(path string) (i int32, err error) {
    37  	b, err := ioutil.ReadFile(path)
    38  	if err != nil {
    39  		return
    40  	}
    41  	_, err = fmt.Sscanf(string(b), "%d", &i)
    42  	return
    43  }
    44  
    45  func main() {
    46  	flag.Parse()
    47  
    48  	pid, err := readIntFromFile("ppid")
    49  	if err != nil {
    50  		fmt.Fprintf(os.Stderr, "error reading pid: %v\n", err)
    51  		os.Exit(254)
    52  	}
    53  
    54  	process, err := process.NewProcess(pid)
    55  	if err != nil {
    56  		fmt.Fprintf(os.Stderr, "unable to create process %d instance: %v\n", pid, err)
    57  		os.Exit(254)
    58  	}
    59  
    60  	if force {
    61  		children, err := process.Children()
    62  		if err != nil {
    63  			fmt.Fprintf(os.Stderr, "cannot get child processes from %d: %v\n", pid, err)
    64  			os.Exit(254)
    65  		}
    66  
    67  		for _, child := range children {
    68  			if err := child.Kill(); err != nil {
    69  				fmt.Fprintf(os.Stderr, "unable to kill process %d: %v\n", child.Pid, err)
    70  				os.Exit(254)
    71  			}
    72  		}
    73  
    74  		if err := process.Kill(); err != nil {
    75  			fmt.Fprintf(os.Stderr, "unable to kill process %d: %v\n", pid, err)
    76  			os.Exit(254)
    77  		}
    78  	} else {
    79  		if process.Terminate() != nil {
    80  			fmt.Fprintf(os.Stderr, "unable to terminate process %d: %v\n", pid, err)
    81  			os.Exit(254)
    82  		}
    83  	}
    84  }