1package vfs // import "github.com/docker/docker/daemon/graphdriver/vfs" 2 3import ( 4 "fmt" 5 "os" 6 "path/filepath" 7 8 "github.com/docker/docker/daemon/graphdriver" 9 "github.com/docker/docker/errdefs" 10 "github.com/docker/docker/pkg/containerfs" 11 "github.com/docker/docker/pkg/idtools" 12 "github.com/docker/docker/pkg/parsers" 13 "github.com/docker/docker/pkg/system" 14 "github.com/docker/docker/quota" 15 units "github.com/docker/go-units" 16 "github.com/opencontainers/selinux/go-selinux/label" 17 "github.com/pkg/errors" 18) 19 20var ( 21 // CopyDir defines the copy method to use. 22 CopyDir = dirCopy 23) 24 25func init() { 26 graphdriver.Register("vfs", Init) 27} 28 29// Init returns a new VFS driver. 30// This sets the home directory for the driver and returns NaiveDiffDriver. 31func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (graphdriver.Driver, error) { 32 d := &Driver{ 33 home: home, 34 idMapping: idtools.NewIDMappingsFromMaps(uidMaps, gidMaps), 35 } 36 37 if err := d.parseOptions(options); err != nil { 38 return nil, err 39 } 40 41 rootIDs := d.idMapping.RootPair() 42 if err := idtools.MkdirAllAndChown(home, 0700, rootIDs); err != nil { 43 return nil, err 44 } 45 46 setupDriverQuota(d) 47 48 if size := d.getQuotaOpt(); !d.quotaSupported() && size > 0 { 49 return nil, quota.ErrQuotaNotSupported 50 } 51 52 return graphdriver.NewNaiveDiffDriver(d, uidMaps, gidMaps), nil 53} 54 55// Driver holds information about the driver, home directory of the driver. 56// Driver implements graphdriver.ProtoDriver. It uses only basic vfs operations. 57// In order to support layering, files are copied from the parent layer into the new layer. There is no copy-on-write support. 58// Driver must be wrapped in NaiveDiffDriver to be used as a graphdriver.Driver 59type Driver struct { 60 driverQuota 61 home string 62 idMapping *idtools.IdentityMapping 63} 64 65func (d *Driver) String() string { 66 return "vfs" 67} 68 69// Status is used for implementing the graphdriver.ProtoDriver interface. VFS does not currently have any status information. 70func (d *Driver) Status() [][2]string { 71 return nil 72} 73 74// GetMetadata is used for implementing the graphdriver.ProtoDriver interface. VFS does not currently have any meta data. 75func (d *Driver) GetMetadata(id string) (map[string]string, error) { 76 return nil, nil 77} 78 79// Cleanup is used to implement graphdriver.ProtoDriver. There is no cleanup required for this driver. 80func (d *Driver) Cleanup() error { 81 return nil 82} 83 84func (d *Driver) parseOptions(options []string) error { 85 for _, option := range options { 86 key, val, err := parsers.ParseKeyValueOpt(option) 87 if err != nil { 88 return errdefs.InvalidParameter(err) 89 } 90 switch key { 91 case "size": 92 size, err := units.RAMInBytes(val) 93 if err != nil { 94 return errdefs.InvalidParameter(err) 95 } 96 if err = d.setQuotaOpt(uint64(size)); err != nil { 97 return errdefs.InvalidParameter(errors.Wrap(err, "failed to set option size for vfs")) 98 } 99 default: 100 return errdefs.InvalidParameter(errors.Errorf("unknown option %s for vfs", key)) 101 } 102 } 103 return nil 104} 105 106// CreateReadWrite creates a layer that is writable for use as a container 107// file system. 108func (d *Driver) CreateReadWrite(id, parent string, opts *graphdriver.CreateOpts) error { 109 quotaSize := d.getQuotaOpt() 110 111 if opts != nil { 112 for key, val := range opts.StorageOpt { 113 switch key { 114 case "size": 115 if !d.quotaSupported() { 116 return quota.ErrQuotaNotSupported 117 } 118 size, err := units.RAMInBytes(val) 119 if err != nil { 120 return errdefs.InvalidParameter(err) 121 } 122 quotaSize = uint64(size) 123 default: 124 return errdefs.InvalidParameter(errors.Errorf("Storage opt %s not supported", key)) 125 } 126 } 127 } 128 129 return d.create(id, parent, quotaSize) 130} 131 132// Create prepares the filesystem for the VFS driver and copies the directory for the given id under the parent. 133func (d *Driver) Create(id, parent string, opts *graphdriver.CreateOpts) error { 134 if opts != nil && len(opts.StorageOpt) != 0 { 135 return fmt.Errorf("--storage-opt is not supported for vfs on read-only layers") 136 } 137 138 return d.create(id, parent, 0) 139} 140 141func (d *Driver) create(id, parent string, size uint64) error { 142 dir := d.dir(id) 143 rootIDs := d.idMapping.RootPair() 144 if err := idtools.MkdirAllAndChown(filepath.Dir(dir), 0700, rootIDs); err != nil { 145 return err 146 } 147 if err := idtools.MkdirAndChown(dir, 0755, rootIDs); err != nil { 148 return err 149 } 150 151 if size != 0 { 152 if err := d.setupQuota(dir, size); err != nil { 153 return err 154 } 155 } 156 157 labelOpts := []string{"level:s0"} 158 if _, mountLabel, err := label.InitLabels(labelOpts); err == nil { 159 label.SetFileLabel(dir, mountLabel) 160 } 161 if parent == "" { 162 return nil 163 } 164 parentDir, err := d.Get(parent, "") 165 if err != nil { 166 return fmt.Errorf("%s: %s", parent, err) 167 } 168 return CopyDir(parentDir.Path(), dir) 169} 170 171func (d *Driver) dir(id string) string { 172 return filepath.Join(d.home, "dir", filepath.Base(id)) 173} 174 175// Remove deletes the content from the directory for a given id. 176func (d *Driver) Remove(id string) error { 177 return system.EnsureRemoveAll(d.dir(id)) 178} 179 180// Get returns the directory for the given id. 181func (d *Driver) Get(id, mountLabel string) (containerfs.ContainerFS, error) { 182 dir := d.dir(id) 183 if st, err := os.Stat(dir); err != nil { 184 return nil, err 185 } else if !st.IsDir() { 186 return nil, fmt.Errorf("%s: not a directory", dir) 187 } 188 return containerfs.NewLocalContainerFS(dir), nil 189} 190 191// Put is a noop for vfs that return nil for the error, since this driver has no runtime resources to clean up. 192func (d *Driver) Put(id string) error { 193 // The vfs driver has no runtime resources (e.g. mounts) 194 // to clean up, so we don't need anything here 195 return nil 196} 197 198// Exists checks to see if the directory exists for the given id. 199func (d *Driver) Exists(id string) bool { 200 _, err := os.Stat(d.dir(id)) 201 return err == nil 202} 203