talm

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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this
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// file, You can obtain one at http://mozilla.org/MPL/2.0/.
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package mount
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import (
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	"bufio"
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	"fmt"
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	"log"
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	"os"
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	"strings"
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	"time"
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	"golang.org/x/sys/unix"
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)
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func unmountWithTimeout(target string, flags int, timeout time.Duration) error {
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	errCh := make(chan error, 1)
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	go func() {
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		errCh <- unix.Unmount(target, flags)
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	}()
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	timer := time.NewTimer(timeout)
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	defer timer.Stop()
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	select {
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	case <-timer.C:
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		return fmt.Errorf("unmounting %s timed out after %s", target, timeout)
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	case err := <-errCh:
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		return err
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	}
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}
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// UnmountAll attempts to unmount all the mounted filesystems via "self" mountinfo.
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func UnmountAll() error {
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	// timeout in seconds
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	const timeout = 10
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	ticker := time.NewTicker(time.Second)
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	defer ticker.Stop()
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	for range timeout {
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		mounts, err := readMountInfo()
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		if err != nil {
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			return err
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		}
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		failedUnmounts := 0
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		for _, mountInfo := range mounts {
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			if mountInfo.MountPoint == "" {
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				continue
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			}
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			if strings.HasPrefix(mountInfo.MountSource, "/dev/") {
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				err = unmountWithTimeout(mountInfo.MountPoint, 0, time.Second)
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				if err == nil {
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					log.Printf("unmounted %s (%s)", mountInfo.MountPoint, mountInfo.MountSource)
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				} else {
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					log.Printf("failed unmounting %s: %s", mountInfo.MountPoint, err)
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					failedUnmounts++
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				}
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			}
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		}
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		if failedUnmounts == 0 {
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			break
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		}
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		log.Printf("retrying %d unmount operations...", failedUnmounts)
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		<-ticker.C
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	}
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	return nil
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}
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type mountInfo struct {
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	MountPoint  string
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	MountSource string
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}
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func readMountInfo() ([]mountInfo, error) {
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	f, err := os.Open("/proc/self/mountinfo")
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	if err != nil {
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		return nil, err
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	}
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	defer f.Close() //nolint:errcheck
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	var mounts []mountInfo
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	scanner := bufio.NewScanner(f)
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	for scanner.Scan() {
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		line := scanner.Text()
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		parts := strings.SplitN(line, " - ", 2)
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		if len(parts) < 2 {
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			continue
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		}
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		var mntInfo mountInfo
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		pre := strings.Fields(parts[0])
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		post := strings.Fields(parts[1])
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		if len(pre) >= 5 {
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			mntInfo.MountPoint = pre[4]
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		}
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		if len(post) >= 1 {
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			mntInfo.MountSource = post[1]
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		}
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		mounts = append(mounts, mntInfo)
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	}
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	return mounts, scanner.Err()
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}
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