| 1 | // FUSE filesystem for the read-only /ipfs mount. go-fuse only builds on linux, darwin, and freebsd. |
| 2 | //go:build (linux || darwin || freebsd) && !nofuse |
| 3 | |
| 4 | package readonly |
| 5 | |
| 6 | import ( |
| 7 | "context" |
| 8 | "io" |
| 9 | "os" |
| 10 | "sync" |
| 11 | "syscall" |
| 12 | "time" |
| 13 | |
| 14 | "github.com/hanwen/go-fuse/v2/fs" |
| 15 | "github.com/hanwen/go-fuse/v2/fuse" |
| 16 | "github.com/ipfs/boxo/files" |
| 17 | mdag "github.com/ipfs/boxo/ipld/merkledag" |
| 18 | ft "github.com/ipfs/boxo/ipld/unixfs" |
| 19 | uio "github.com/ipfs/boxo/ipld/unixfs/io" |
| 20 | "github.com/ipfs/boxo/path" |
| 21 | "github.com/ipfs/go-cid" |
| 22 | ipld "github.com/ipfs/go-ipld-format" |
| 23 | logging "github.com/ipfs/go-log/v2" |
| 24 | core "github.com/ipfs/kubo/core" |
| 25 | fusemnt "github.com/ipfs/kubo/fuse/mount" |
| 26 | cidlink "github.com/ipld/go-ipld-prime/linking/cid" |
| 27 | ) |
| 28 | |
| 29 | var log = logging.Logger("fuse/ipfs") |
| 30 | |
| 31 | // /ipfs paths are immutable (content-addressed by CID), so the kernel |
| 32 | // can cache attributes and directory entries for as long as it wants. |
| 33 | // var (not const) because fs.Options needs a *time.Duration. |
| 34 | var immutableAttrCacheTime = 365 * 24 * time.Hour |
| 35 | |
| 36 | // Root is the root object of the /ipfs filesystem tree. |
| 37 | type Root struct { |
| 38 | fs.Inode |
| 39 | ipfs *core.IpfsNode |
| 40 | repoPath string |
| 41 | } |
| 42 | |
| 43 | // NewRoot constructs a new readonly root node. |
| 44 | func NewRoot(ipfs *core.IpfsNode) *Root { |
| 45 | return &Root{ipfs: ipfs, repoPath: ipfs.Repo.Path()} |
| 46 | } |
| 47 | |
| 48 | // Statfs reports disk-space statistics for the underlying filesystem. |
| 49 | // macOS Finder checks free space before copying; without this it |
| 50 | // reports "not enough free space" because go-fuse returns zeroed stats. |
| 51 | func (r *Root) Statfs(_ context.Context, out *fuse.StatfsOut) syscall.Errno { |
| 52 | if r.repoPath == "" { |
| 53 | return 0 |
| 54 | } |
| 55 | var s syscall.Statfs_t |
| 56 | if err := syscall.Statfs(r.repoPath, &s); err != nil { |
| 57 | return fs.ToErrno(err) |
| 58 | } |
| 59 | out.FromStatfsT(&s) |
| 60 | return 0 |
| 61 | } |
| 62 | |
| 63 | func (*Root) Getattr(_ context.Context, _ fs.FileHandle, out *fuse.AttrOut) syscall.Errno { |
| 64 | out.Attr.Mode = uint32(fusemnt.NamespaceRootMode.Perm()) |
| 65 | out.SetTimeout(immutableAttrCacheTime) |
| 66 | return 0 |
| 67 | } |
| 68 | |
| 69 | func (r *Root) Lookup(ctx context.Context, name string, out *fuse.EntryOut) (*fs.Inode, syscall.Errno) { |
| 70 | log.Debugf("Root Lookup: '%s'", name) |
| 71 | switch name { |
| 72 | case "mach_kernel", ".hidden", "._.": |
| 73 | return nil, syscall.ENOENT |
| 74 | } |
| 75 | |
| 76 | p, err := path.NewPath("/ipfs/" + name) |
| 77 | if err != nil { |
| 78 | log.Debugf("fuse failed to parse path: %q: %s", name, err) |
| 79 | return nil, syscall.ENOENT |
| 80 | } |
| 81 | |
| 82 | imPath, err := path.NewImmutablePath(p) |
| 83 | if err != nil { |
| 84 | log.Debugf("fuse failed to convert path: %q: %s", name, err) |
| 85 | return nil, syscall.ENOENT |
| 86 | } |
| 87 | |
| 88 | nd, ndLnk, err := r.ipfs.UnixFSPathResolver.ResolvePath(ctx, imPath) |
| 89 | if err != nil { |
| 90 | return nil, syscall.ENOENT |
| 91 | } |
| 92 | |
| 93 | cidLnk, ok := ndLnk.(cidlink.Link) |
| 94 | if !ok { |
| 95 | log.Debugf("non-cidlink returned from ResolvePath: %v", ndLnk) |
| 96 | return nil, syscall.ENOENT |
| 97 | } |
| 98 | |
| 99 | blk, err := r.ipfs.Blockstore.Get(ctx, cidLnk.Cid) |
| 100 | if err != nil { |
| 101 | log.Debugf("fuse failed to retrieve block: %v: %s", cidLnk, err) |
| 102 | return nil, syscall.ENOENT |
| 103 | } |
| 104 | |
| 105 | var fnd ipld.Node |
| 106 | switch cidLnk.Cid.Prefix().Codec { |
| 107 | case cid.DagProtobuf: |
| 108 | fnd, err = mdag.DecodeProtobuf(blk.RawData()) |
| 109 | case cid.Raw: |
| 110 | fnd, err = mdag.RawNodeConverter(blk, nd) |
| 111 | default: |
| 112 | log.Error("fuse node was not a supported type") |
| 113 | return nil, syscall.ENOTSUP |
| 114 | } |
| 115 | if err != nil { |
| 116 | log.Errorf("could not decode block as protobuf or raw node: %s", err) |
| 117 | return nil, syscall.ENOENT |
| 118 | } |
| 119 | |
| 120 | child := &Node{ipfs: r.ipfs, nd: fnd} |
| 121 | stable := stableAttrFor(child) |
| 122 | |
| 123 | // Fill attrs in the lookup response so the kernel doesn't cache zeros. |
| 124 | child.fillAttr(&out.Attr) |
| 125 | out.SetEntryTimeout(immutableAttrCacheTime) |
| 126 | out.SetAttrTimeout(immutableAttrCacheTime) |
| 127 | return r.NewInode(ctx, child, stable), 0 |
| 128 | } |
| 129 | |
| 130 | // Readdir on the namespace root is not allowed (execute-only). |
| 131 | func (*Root) Readdir(_ context.Context) (fs.DirStream, syscall.Errno) { |
| 132 | return nil, syscall.EPERM |
| 133 | } |
| 134 | |
| 135 | // Node is the core object representing a filesystem tree node. |
| 136 | type Node struct { |
| 137 | fs.Inode |
| 138 | ipfs *core.IpfsNode |
| 139 | nd ipld.Node |
| 140 | cached *ft.FSNode |
| 141 | } |
| 142 | |
| 143 | func (n *Node) loadData() error { |
| 144 | if pbnd, ok := n.nd.(*mdag.ProtoNode); ok { |
| 145 | fsn, err := ft.FSNodeFromBytes(pbnd.Data()) |
| 146 | if err != nil { |
| 147 | return err |
| 148 | } |
| 149 | n.cached = fsn |
| 150 | } |
| 151 | return nil |
| 152 | } |
| 153 | |
| 154 | func (n *Node) Getattr(_ context.Context, _ fs.FileHandle, out *fuse.AttrOut) syscall.Errno { |
| 155 | log.Debug("Node attr") |
| 156 | out.SetTimeout(immutableAttrCacheTime) |
| 157 | n.fillAttr(&out.Attr) |
| 158 | return 0 |
| 159 | } |
| 160 | |
| 161 | // Open creates a DagReader that is reused across sequential Read |
| 162 | // calls, avoiding re-traversal of the DAG from the root on each read. |
| 163 | func (n *Node) Open(ctx context.Context, _ uint32) (fs.FileHandle, uint32, syscall.Errno) { |
| 164 | r, err := uio.NewDagReader(ctx, n.nd, n.ipfs.DAG) |
| 165 | if err != nil { |
| 166 | return nil, 0, fusemnt.ReadErrno(err) |
| 167 | } |
| 168 | return &roFileHandle{r: r}, fuse.FOPEN_KEEP_CACHE, 0 |
| 169 | } |
| 170 | |
| 171 | // roFileHandle holds a DagReader for the lifetime of an open file. |
| 172 | // All methods are serialized by mu because the FUSE server dispatches |
| 173 | // each request in its own goroutine and the underlying DagReader is |
| 174 | // not safe for concurrent use. |
| 175 | type roFileHandle struct { |
| 176 | r uio.DagReader |
| 177 | mu sync.Mutex |
| 178 | } |
| 179 | |
| 180 | // fillAttr populates a fuse.Attr from this node's UnixFS metadata. |
| 181 | // Used by both Getattr and Lookup (to fill EntryOut.Attr so the kernel |
| 182 | // doesn't cache zero values for the entry timeout duration). |
| 183 | // |
| 184 | // Blocks and Blksize are set on every entry because go-fuse's setBlocks |
| 185 | // otherwise auto-fills them from Size with a 4 KiB page-based fallback, |
| 186 | // which clobbers the UnixFS-derived values set below. |
| 187 | func (n *Node) fillAttr(a *fuse.Attr) { |
| 188 | a.Blksize = fusemnt.DefaultBlksize |
| 189 | |
| 190 | if rawnd, ok := n.nd.(*mdag.RawNode); ok { |
| 191 | a.Mode = uint32(fusemnt.DefaultFileModeRO.Perm()) |
| 192 | a.Size = uint64(len(rawnd.RawData())) |
| 193 | a.Blocks = fusemnt.SizeToStatBlocks(a.Size) |
| 194 | return |
| 195 | } |
| 196 | |
| 197 | if n.cached == nil { |
| 198 | if err := n.loadData(); err != nil { |
| 199 | log.Errorf("readonly: loadData() failed: %s", err) |
| 200 | return |
| 201 | } |
| 202 | } |
| 203 | |
| 204 | switch n.cached.Type() { |
| 205 | case ft.TDirectory, ft.THAMTShard: |
| 206 | a.Mode = uint32(fusemnt.DefaultDirModeRO.Perm()) |
| 207 | // Nominal 1 block: du sums child leaves, so the directory's |
| 208 | // own st_blocks is not arithmetically meaningful, but some |
| 209 | // tools treat 0 as "unsupported" and skip the entry. |
| 210 | a.Blocks = 1 |
| 211 | case ft.TFile: |
| 212 | a.Mode = uint32(fusemnt.DefaultFileModeRO.Perm()) |
| 213 | a.Size = n.cached.FileSize() |
| 214 | a.Blocks = fusemnt.SizeToStatBlocks(a.Size) |
| 215 | case ft.TRaw: |
| 216 | a.Mode = uint32(fusemnt.DefaultFileModeRO.Perm()) |
| 217 | a.Size = uint64(len(n.cached.Data())) |
| 218 | a.Blocks = fusemnt.SizeToStatBlocks(a.Size) |
| 219 | case ft.TSymlink: |
| 220 | a.Mode = uint32(fusemnt.SymlinkMode.Perm()) |
| 221 | a.Size = uint64(len(n.cached.Data())) |
| 222 | a.Blocks = fusemnt.SizeToStatBlocks(a.Size) |
| 223 | default: |
| 224 | log.Errorf("invalid data type: %s", n.cached.Type()) |
| 225 | return |
| 226 | } |
| 227 | |
| 228 | // Use mode and mtime from UnixFS metadata when present. |
| 229 | if m := n.cached.Mode(); m != 0 { |
| 230 | a.Mode = files.ModePermsToUnixPerms(m) |
| 231 | } |
| 232 | if t := n.cached.ModTime(); !t.IsZero() { |
| 233 | a.SetTimes(nil, &t, nil) |
| 234 | } |
| 235 | } |
| 236 | |
| 237 | func (n *Node) Lookup(ctx context.Context, name string, out *fuse.EntryOut) (*fs.Inode, syscall.Errno) { |
| 238 | log.Debugf("Lookup '%s'", name) |
| 239 | link, _, err := uio.ResolveUnixfsOnce(ctx, n.ipfs.DAG, n.nd, []string{name}) |
| 240 | switch err { |
| 241 | case os.ErrNotExist, mdag.ErrLinkNotFound: |
| 242 | return nil, syscall.ENOENT |
| 243 | case nil: |
| 244 | default: |
| 245 | log.Errorf("fuse lookup %q: %s", name, err) |
| 246 | return nil, syscall.EIO |
| 247 | } |
| 248 | |
| 249 | nd, err := n.ipfs.DAG.Get(ctx, link.Cid) |
| 250 | if err != nil && !ipld.IsNotFound(err) { |
| 251 | log.Errorf("fuse lookup %q: %s", name, err) |
| 252 | return nil, syscall.EIO |
| 253 | } |
| 254 | |
| 255 | child := &Node{ipfs: n.ipfs, nd: nd} |
| 256 | stable := stableAttrFor(child) |
| 257 | |
| 258 | child.fillAttr(&out.Attr) |
| 259 | out.SetEntryTimeout(immutableAttrCacheTime) |
| 260 | out.SetAttrTimeout(immutableAttrCacheTime) |
| 261 | return n.NewInode(ctx, child, stable), 0 |
| 262 | } |
| 263 | |
| 264 | func (n *Node) Readdir(ctx context.Context) (fs.DirStream, syscall.Errno) { |
| 265 | log.Debug("Node ReadDir") |
| 266 | dir, err := uio.NewDirectoryFromNode(n.ipfs.DAG, n.nd) |
| 267 | if err != nil { |
| 268 | return nil, fusemnt.ReadErrno(err) |
| 269 | } |
| 270 | |
| 271 | var entries []fuse.DirEntry |
| 272 | err = dir.ForEachLink(ctx, func(lnk *ipld.Link) error { |
| 273 | name := lnk.Name |
| 274 | if len(name) == 0 { |
| 275 | name = lnk.Cid.String() |
| 276 | } |
| 277 | nd, err := n.ipfs.DAG.Get(ctx, lnk.Cid) |
| 278 | if err != nil { |
| 279 | log.Warn("error fetching directory child node: ", err) |
| 280 | return err |
| 281 | } |
| 282 | |
| 283 | var mode uint32 |
| 284 | switch nd := nd.(type) { |
| 285 | case *mdag.RawNode: |
| 286 | // regular file (mode 0 = S_IFREG) |
| 287 | case *mdag.ProtoNode: |
| 288 | if fsn, err := ft.FSNodeFromBytes(nd.Data()); err != nil { |
| 289 | log.Warn("failed to unmarshal protonode data field:", err) |
| 290 | } else { |
| 291 | switch fsn.Type() { |
| 292 | case ft.TDirectory, ft.THAMTShard: |
| 293 | mode = syscall.S_IFDIR |
| 294 | case ft.TFile, ft.TRaw: |
| 295 | // regular file |
| 296 | case ft.TSymlink: |
| 297 | mode = syscall.S_IFLNK |
| 298 | case ft.TMetadata: |
| 299 | log.Error("metadata object in fuse should contain its wrapped type") |
| 300 | default: |
| 301 | log.Error("unrecognized protonode data type: ", fsn.Type()) |
| 302 | } |
| 303 | } |
| 304 | } |
| 305 | entries = append(entries, fuse.DirEntry{Name: name, Mode: mode}) |
| 306 | return nil |
| 307 | }) |
| 308 | if err != nil { |
| 309 | return nil, fusemnt.ReadErrno(err) |
| 310 | } |
| 311 | |
| 312 | return fs.NewListDirStream(entries), 0 |
| 313 | } |
| 314 | |
| 315 | func (n *Node) Listxattr(_ context.Context, dest []byte) (uint32, syscall.Errno) { |
| 316 | // Null-terminated list of attribute names. |
| 317 | data := []byte(fusemnt.XattrCID + "\x00") |
| 318 | if len(dest) == 0 { |
| 319 | return uint32(len(data)), 0 |
| 320 | } |
| 321 | if len(dest) < len(data) { |
| 322 | return 0, syscall.ERANGE |
| 323 | } |
| 324 | return uint32(copy(dest, data)), 0 |
| 325 | } |
| 326 | |
| 327 | func (n *Node) Getxattr(_ context.Context, attr string, dest []byte) (uint32, syscall.Errno) { |
| 328 | if attr == fusemnt.XattrCIDDeprecated { |
| 329 | log.Errorf("xattr %q is deprecated, use %q instead", fusemnt.XattrCIDDeprecated, fusemnt.XattrCID) |
| 330 | attr = fusemnt.XattrCID |
| 331 | } |
| 332 | if attr != fusemnt.XattrCID { |
| 333 | return 0, fs.ENOATTR |
| 334 | } |
| 335 | data := []byte(n.nd.Cid().String()) |
| 336 | if len(dest) == 0 { |
| 337 | return uint32(len(data)), 0 |
| 338 | } |
| 339 | if len(dest) < len(data) { |
| 340 | return 0, syscall.ERANGE |
| 341 | } |
| 342 | return uint32(copy(dest, data)), 0 |
| 343 | } |
| 344 | |
| 345 | func (n *Node) Readlink(_ context.Context) ([]byte, syscall.Errno) { |
| 346 | if n.cached == nil || n.cached.Type() != ft.TSymlink { |
| 347 | return nil, syscall.EINVAL |
| 348 | } |
| 349 | return n.cached.Data(), 0 |
| 350 | } |
| 351 | |
| 352 | func (fh *roFileHandle) Read(ctx context.Context, dest []byte, off int64) (fuse.ReadResult, syscall.Errno) { |
| 353 | fh.mu.Lock() |
| 354 | defer fh.mu.Unlock() |
| 355 | |
| 356 | if _, err := fh.r.Seek(off, io.SeekStart); err != nil { |
| 357 | return nil, fusemnt.ReadErrno(err) |
| 358 | } |
| 359 | n, err := fh.r.CtxReadFull(ctx, dest) |
| 360 | switch err { |
| 361 | case nil, io.EOF, io.ErrUnexpectedEOF: |
| 362 | default: |
| 363 | return nil, fusemnt.ReadErrno(err) |
| 364 | } |
| 365 | return fuse.ReadResultData(dest[:n]), 0 |
| 366 | } |
| 367 | |
| 368 | func (fh *roFileHandle) Release(_ context.Context) syscall.Errno { |
| 369 | fh.mu.Lock() |
| 370 | defer fh.mu.Unlock() |
| 371 | |
| 372 | return fs.ToErrno(fh.r.Close()) |
| 373 | } |
| 374 | |
| 375 | // stableAttrFor returns the StableAttr (file type bits) for a Node. |
| 376 | func stableAttrFor(n *Node) fs.StableAttr { |
| 377 | if _, ok := n.nd.(*mdag.RawNode); ok { |
| 378 | return fs.StableAttr{} // S_IFREG |
| 379 | } |
| 380 | if n.cached == nil { |
| 381 | _ = n.loadData() |
| 382 | } |
| 383 | if n.cached != nil { |
| 384 | switch n.cached.Type() { |
| 385 | case ft.TDirectory, ft.THAMTShard: |
| 386 | return fs.StableAttr{Mode: syscall.S_IFDIR} |
| 387 | case ft.TSymlink: |
| 388 | return fs.StableAttr{Mode: syscall.S_IFLNK} |
| 389 | } |
| 390 | } |
| 391 | return fs.StableAttr{} // S_IFREG |
| 392 | } |
| 393 | |
| 394 | // Interface checks. |
| 395 | var ( |
| 396 | _ fs.NodeGetattrer = (*Root)(nil) |
| 397 | _ fs.NodeLookuper = (*Root)(nil) |
| 398 | _ fs.NodeReaddirer = (*Root)(nil) |
| 399 | _ fs.NodeStatfser = (*Root)(nil) |
| 400 | _ fs.NodeGetattrer = (*Node)(nil) |
| 401 | _ fs.NodeLookuper = (*Node)(nil) |
| 402 | _ fs.NodeOpener = (*Node)(nil) |
| 403 | _ fs.NodeReaddirer = (*Node)(nil) |
| 404 | _ fs.NodeReadlinker = (*Node)(nil) |
| 405 | _ fs.NodeGetxattrer = (*Node)(nil) |
| 406 | _ fs.NodeListxattrer = (*Node)(nil) |
| 407 | |
| 408 | _ fs.FileReader = (*roFileHandle)(nil) |
| 409 | _ fs.FileReleaser = (*roFileHandle)(nil) |
| 410 | ) |