github.com/mforkel/docker-ce-i386@v17.12.1-ce-rc2+incompatible/components/engine/daemon/daemon_linux.go (about)

     1  package daemon
     2  
     3  import (
     4  	"bufio"
     5  	"fmt"
     6  	"io"
     7  	"os"
     8  	"regexp"
     9  	"strings"
    10  
    11  	"github.com/docker/docker/pkg/fileutils"
    12  	"github.com/docker/docker/pkg/mount"
    13  	"github.com/pkg/errors"
    14  	"github.com/sirupsen/logrus"
    15  )
    16  
    17  // On Linux, plugins use a static path for storing execution state,
    18  // instead of deriving path from daemon's exec-root. This is because
    19  // plugin socket files are created here and they cannot exceed max
    20  // path length of 108 bytes.
    21  func getPluginExecRoot(root string) string {
    22  	return "/run/docker/plugins"
    23  }
    24  
    25  func (daemon *Daemon) cleanupMountsByID(id string) error {
    26  	logrus.Debugf("Cleaning up old mountid %s: start.", id)
    27  	f, err := os.Open("/proc/self/mountinfo")
    28  	if err != nil {
    29  		return err
    30  	}
    31  	defer f.Close()
    32  
    33  	return daemon.cleanupMountsFromReaderByID(f, id, mount.Unmount)
    34  }
    35  
    36  func (daemon *Daemon) cleanupMountsFromReaderByID(reader io.Reader, id string, unmount func(target string) error) error {
    37  	if daemon.root == "" {
    38  		return nil
    39  	}
    40  	var errors []string
    41  
    42  	regexps := getCleanPatterns(id)
    43  	sc := bufio.NewScanner(reader)
    44  	for sc.Scan() {
    45  		if fields := strings.Fields(sc.Text()); len(fields) >= 4 {
    46  			if mnt := fields[4]; strings.HasPrefix(mnt, daemon.root) {
    47  				for _, p := range regexps {
    48  					if p.MatchString(mnt) {
    49  						if err := unmount(mnt); err != nil {
    50  							logrus.Error(err)
    51  							errors = append(errors, err.Error())
    52  						}
    53  					}
    54  				}
    55  			}
    56  		}
    57  	}
    58  
    59  	if err := sc.Err(); err != nil {
    60  		return err
    61  	}
    62  
    63  	if len(errors) > 0 {
    64  		return fmt.Errorf("Error cleaning up mounts:\n%v", strings.Join(errors, "\n"))
    65  	}
    66  
    67  	logrus.Debugf("Cleaning up old mountid %v: done.", id)
    68  	return nil
    69  }
    70  
    71  // cleanupMounts umounts used by container resources and the daemon root mount
    72  func (daemon *Daemon) cleanupMounts() error {
    73  	if err := daemon.cleanupMountsByID(""); err != nil {
    74  		return err
    75  	}
    76  
    77  	infos, err := mount.GetMounts()
    78  	if err != nil {
    79  		return errors.Wrap(err, "error reading mount table for cleanup")
    80  	}
    81  
    82  	info := getMountInfo(infos, daemon.root)
    83  	// `info.Root` here is the root mountpoint of the passed in path (`daemon.root`).
    84  	// The ony cases that need to be cleaned up is when the daemon has performed a
    85  	//   `mount --bind /daemon/root /daemon/root && mount --make-shared /daemon/root`
    86  	// This is only done when the daemon is started up and `/daemon/root` is not
    87  	// already on a shared mountpoint.
    88  	if !shouldUnmountRoot(daemon.root, info) {
    89  		return nil
    90  	}
    91  
    92  	logrus.WithField("mountpoint", daemon.root).Debug("unmounting daemon root")
    93  	return mount.Unmount(daemon.root)
    94  }
    95  
    96  func getCleanPatterns(id string) (regexps []*regexp.Regexp) {
    97  	var patterns []string
    98  	if id == "" {
    99  		id = "[0-9a-f]{64}"
   100  		patterns = append(patterns, "containers/"+id+"/shm")
   101  	}
   102  	patterns = append(patterns, "aufs/mnt/"+id+"$", "overlay/"+id+"/merged$", "zfs/graph/"+id+"$")
   103  	for _, p := range patterns {
   104  		r, err := regexp.Compile(p)
   105  		if err == nil {
   106  			regexps = append(regexps, r)
   107  		}
   108  	}
   109  	return
   110  }
   111  
   112  func getRealPath(path string) (string, error) {
   113  	return fileutils.ReadSymlinkedDirectory(path)
   114  }
   115  
   116  func shouldUnmountRoot(root string, info *mount.Info) bool {
   117  	if info == nil {
   118  		return false
   119  	}
   120  	if info.Mountpoint != root {
   121  		return false
   122  	}
   123  	if !strings.HasSuffix(root, info.Root) {
   124  		return false
   125  	}
   126  	return hasMountinfoOption(info.Optional, sharedPropagationOption)
   127  }