| 1 | //go:build linux |
| 2 | |
| 3 | package park |
| 4 | |
| 5 | import ( |
| 6 | "bytes" |
| 7 | "context" |
| 8 | "crypto/rand" |
| 9 | "encoding/hex" |
| 10 | "encoding/json" |
| 11 | "errors" |
| 12 | "io" |
| 13 | "os" |
| 14 | "reflect" |
| 15 | "strings" |
| 16 | |
| 17 | "golang.org/x/sys/unix" |
| 18 | ) |
| 19 | |
| 20 | func localSupported() bool { return true } |
| 21 | |
| 22 | func localDirAt(parent int, name string, create bool) (int, error) { |
| 23 | if !localComponent(name) { |
| 24 | return -1, ErrLocalInventory |
| 25 | } |
| 26 | if create { |
| 27 | if err := unix.Mkdirat(parent, name, 0770); err != nil && !errors.Is(err, unix.EEXIST) { |
| 28 | return -1, err |
| 29 | } |
| 30 | } |
| 31 | fd, err := unix.Openat(parent, name, unix.O_RDONLY|unix.O_DIRECTORY|unix.O_NOFOLLOW|unix.O_CLOEXEC, 0) |
| 32 | if err != nil { |
| 33 | return -1, err |
| 34 | } |
| 35 | var st unix.Stat_t |
| 36 | if err := unix.Fstat(fd, &st); err != nil || st.Mode&unix.S_IFMT != unix.S_IFDIR { |
| 37 | unix.Close(fd) |
| 38 | if err != nil { |
| 39 | return -1, err |
| 40 | } |
| 41 | return -1, ErrLocalInventory |
| 42 | } |
| 43 | if create { |
| 44 | // A retry can encounter another worker's directory. Root also respects its owner. |
| 45 | if st.Uid == uint32(os.Geteuid()) { |
| 46 | if err := unix.Fchmod(fd, 02770); err != nil { |
| 47 | unix.Close(fd) |
| 48 | return -1, err |
| 49 | } |
| 50 | } else if st.Mode&02770 != 02770 { |
| 51 | unix.Close(fd) |
| 52 | return -1, ErrLocalInventory |
| 53 | } |
| 54 | if err := unix.Fsync(fd); err != nil { |
| 55 | unix.Close(fd) |
| 56 | return -1, err |
| 57 | } |
| 58 | if err := unix.Fsync(parent); err != nil { |
| 59 | unix.Close(fd) |
| 60 | return -1, err |
| 61 | } |
| 62 | } |
| 63 | return fd, nil |
| 64 | } |
| 65 | |
| 66 | func localWalk(root int, parts []string, create bool) (int, error) { |
| 67 | fd, err := unix.Dup(root) |
| 68 | if err != nil { |
| 69 | return -1, err |
| 70 | } |
| 71 | unix.CloseOnExec(fd) |
| 72 | for _, p := range parts { |
| 73 | next, err := localDirAt(fd, p, create) |
| 74 | unix.Close(fd) |
| 75 | if err != nil { |
| 76 | return -1, err |
| 77 | } |
| 78 | fd = next |
| 79 | } |
| 80 | return fd, nil |
| 81 | } |
| 82 | |
| 83 | func localParent(root int, p string, create bool) (int, string, error) { |
| 84 | if !localPath(p) { |
| 85 | return -1, "", ErrLocalInventory |
| 86 | } |
| 87 | parts := strings.Split(p, "/") |
| 88 | fd, err := localWalk(root, parts[:len(parts)-1], create) |
| 89 | return fd, parts[len(parts)-1], err |
| 90 | } |
| 91 | |
| 92 | func localStat(fd int, name string) (unix.Stat_t, error) { |
| 93 | var st unix.Stat_t |
| 94 | err := unix.Fstatat(fd, name, &st, unix.AT_SYMLINK_NOFOLLOW) |
| 95 | if err == nil && st.Mode&unix.S_IFMT != unix.S_IFDIR && st.Mode&unix.S_IFMT != unix.S_IFREG { |
| 96 | return st, ErrLocalInventory |
| 97 | } |
| 98 | return st, err |
| 99 | } |
| 100 | |
| 101 | func localSame(st unix.Stat_t, item localItem) bool { |
| 102 | return uint64(st.Dev) == item.Dev && st.Ino == item.Ino && st.Mode&unix.S_IFMT == item.Type |
| 103 | } |
| 104 | |
| 105 | func localReadJournal(dir int) (*localJournal, error) { |
| 106 | fd, err := unix.Openat(dir, ".journal.json", unix.O_RDONLY|unix.O_NOFOLLOW|unix.O_CLOEXEC|unix.O_NONBLOCK, 0) |
| 107 | if err != nil { |
| 108 | return nil, err |
| 109 | } |
| 110 | f := os.NewFile(uintptr(fd), "journal") |
| 111 | defer f.Close() |
| 112 | st, err := f.Stat() |
| 113 | if err != nil { |
| 114 | return nil, err |
| 115 | } |
| 116 | if !st.Mode().IsRegular() { |
| 117 | return nil, ErrLocalJournal |
| 118 | } |
| 119 | b, err := io.ReadAll(io.LimitReader(f, (4<<20)+1)) |
| 120 | if err != nil { |
| 121 | return nil, err |
| 122 | } |
| 123 | if len(b) > 4<<20 { |
| 124 | return nil, ErrLocalJournal |
| 125 | } |
| 126 | d := json.NewDecoder(bytes.NewReader(b)) |
| 127 | d.DisallowUnknownFields() |
| 128 | var j localJournal |
| 129 | if err := d.Decode(&j); err != nil { |
| 130 | return nil, err |
| 131 | } |
| 132 | if _, err := d.Token(); err != io.EOF { |
| 133 | return nil, ErrLocalJournal |
| 134 | } |
| 135 | return &j, nil |
| 136 | } |
| 137 | |
| 138 | func localWriteJournal(dir int, j *localJournal) error { |
| 139 | b, err := json.Marshal(j) |
| 140 | if err != nil { |
| 141 | return err |
| 142 | } |
| 143 | var nonce [16]byte |
| 144 | if _, err := rand.Read(nonce[:]); err != nil { |
| 145 | return err |
| 146 | } |
| 147 | name := ".journal-" + hex.EncodeToString(nonce[:]) |
| 148 | fd, err := unix.Openat(dir, name, unix.O_WRONLY|unix.O_CREAT|unix.O_EXCL|unix.O_NOFOLLOW|unix.O_CLOEXEC, 0660) |
| 149 | if err != nil { |
| 150 | return err |
| 151 | } |
| 152 | f := os.NewFile(uintptr(fd), "journal-temp") |
| 153 | defer f.Close() |
| 154 | defer unix.Unlinkat(dir, name, 0) |
| 155 | if err := unix.Fchmod(fd, 0660); err != nil { |
| 156 | return err |
| 157 | } |
| 158 | if _, err := f.Write(b); err != nil { |
| 159 | return err |
| 160 | } |
| 161 | if err := f.Sync(); err != nil { |
| 162 | return err |
| 163 | } |
| 164 | if err := unix.Renameat(dir, name, dir, ".journal.json"); err != nil { |
| 165 | return err |
| 166 | } |
| 167 | return unix.Fsync(dir) |
| 168 | } |
| 169 | |
| 170 | func localJournalMatches(a, b localJournal) bool { |
| 171 | if len(a.Items) != len(b.Items) { |
| 172 | return false |
| 173 | } |
| 174 | for i := range a.Items { |
| 175 | if a.Items[i].Path != b.Items[i].Path || a.Items[i].Stamp != b.Items[i].Stamp { |
| 176 | return false |
| 177 | } |
| 178 | if a.Items[i].Missing { |
| 179 | if a.Items[i].Dev != 0 || a.Items[i].Ino != 0 || a.Items[i].Type != 0 { |
| 180 | return false |
| 181 | } |
| 182 | } else if a.Items[i].Ino == 0 || (a.Items[i].Type != unix.S_IFDIR && a.Items[i].Type != unix.S_IFREG) { |
| 183 | return false |
| 184 | } |
| 185 | } |
| 186 | a.Items, b.Items = nil, nil |
| 187 | return reflect.DeepEqual(a, b) |
| 188 | } |
| 189 | |
| 190 | func (l Local) parkLocal(ctx context.Context, want *localJournal) error { |
| 191 | root, err := unix.Open(l.DataDir, unix.O_RDONLY|unix.O_DIRECTORY|unix.O_NOFOLLOW|unix.O_CLOEXEC, 0) |
| 192 | if err != nil { |
| 193 | return err |
| 194 | } |
| 195 | defer unix.Close(root) |
| 196 | parked, err := localDirAt(root, ".parked", false) |
| 197 | if err != nil { |
| 198 | return err |
| 199 | } |
| 200 | defer unix.Close(parked) |
| 201 | event, err := localWalk(parked, []string{want.Incarnation, want.Host, want.Retirement}, true) |
| 202 | if err != nil { |
| 203 | return err |
| 204 | } |
| 205 | defer unix.Close(event) |
| 206 | dest, err := localDirAt(event, "artifacts", true) |
| 207 | if err != nil { |
| 208 | return err |
| 209 | } |
| 210 | defer unix.Close(dest) |
| 211 | prior, err := localReadJournal(event) |
| 212 | if errors.Is(err, unix.ENOENT) { |
| 213 | for i := range want.Items { |
| 214 | it := &want.Items[i] |
| 215 | src, name, e := localParent(root, it.Path, false) |
| 216 | if errors.Is(e, unix.ENOENT) { |
| 217 | it.Missing = true |
| 218 | continue |
| 219 | } |
| 220 | if e != nil { |
| 221 | return e |
| 222 | } |
| 223 | st, e := localStat(src, name) |
| 224 | unix.Close(src) |
| 225 | if errors.Is(e, unix.ENOENT) { |
| 226 | it.Missing = true |
| 227 | continue |
| 228 | } |
| 229 | if e != nil { |
| 230 | return e |
| 231 | } |
| 232 | it.Dev, it.Ino, it.Type = uint64(st.Dev), st.Ino, st.Mode&unix.S_IFMT |
| 233 | dp, dn, e := localParent(dest, it.Path, true) |
| 234 | if e != nil { |
| 235 | return e |
| 236 | } |
| 237 | _, e = localStat(dp, dn) |
| 238 | unix.Close(dp) |
| 239 | if !errors.Is(e, unix.ENOENT) { |
| 240 | if e != nil { |
| 241 | return e |
| 242 | } |
| 243 | return ErrLocalJournal |
| 244 | } |
| 245 | } |
| 246 | if err := localWriteJournal(event, want); err != nil { |
| 247 | return err |
| 248 | } |
| 249 | } else if err != nil { |
| 250 | return err |
| 251 | } else { |
| 252 | if !localJournalMatches(*prior, *want) { |
| 253 | return ErrLocalJournal |
| 254 | } |
| 255 | *want = *prior |
| 256 | } |
| 257 | for i := range want.Items { |
| 258 | if err := ctx.Err(); err != nil { |
| 259 | return err |
| 260 | } |
| 261 | it := &want.Items[i] |
| 262 | if it.Missing { |
| 263 | // A still-active installation can recreate an absent path between attempts. |
| 264 | sp, sn, err := localParent(root, it.Path, false) |
| 265 | if err == nil { |
| 266 | _, err = localStat(sp, sn) |
| 267 | unix.Close(sp) |
| 268 | } |
| 269 | if !errors.Is(err, unix.ENOENT) { |
| 270 | if err != nil { |
| 271 | return err |
| 272 | } |
| 273 | return ErrLocalJournal |
| 274 | } |
| 275 | it.Done = true |
| 276 | continue |
| 277 | } |
| 278 | dp, dn, err := localParent(dest, it.Path, true) |
| 279 | if err != nil { |
| 280 | return err |
| 281 | } |
| 282 | sp, sn, err := localParent(root, it.Path, false) |
| 283 | if err != nil { |
| 284 | unix.Close(dp) |
| 285 | return err |
| 286 | } |
| 287 | err = l.moveLocalItem(sp, sn, dp, dn, it) |
| 288 | if err == nil { |
| 289 | err = unix.Fsync(sp) |
| 290 | } |
| 291 | if err == nil { |
| 292 | err = unix.Fsync(dp) |
| 293 | } |
| 294 | unix.Close(sp) |
| 295 | unix.Close(dp) |
| 296 | if err != nil { |
| 297 | return err |
| 298 | } |
| 299 | it.Done = true |
| 300 | if err := localWriteJournal(event, want); err != nil { |
| 301 | return err |
| 302 | } |
| 303 | } |
| 304 | if err := localWriteJournal(event, want); err != nil { |
| 305 | return err |
| 306 | } |
| 307 | if err := unix.Fsync(dest); err != nil { |
| 308 | return err |
| 309 | } |
| 310 | return unix.Fsync(event) |
| 311 | } |
| 312 | |
| 313 | func (l Local) moveLocalItem(sp int, sn string, dp int, dn string, it *localItem) error { |
| 314 | dst, de := localStat(dp, dn) |
| 315 | if de == nil { |
| 316 | if !localSame(dst, *it) { |
| 317 | return ErrLocalJournal |
| 318 | } |
| 319 | _, se := localStat(sp, sn) |
| 320 | if se == nil { |
| 321 | return ErrLocalJournal |
| 322 | } |
| 323 | if se != nil && !errors.Is(se, unix.ENOENT) { |
| 324 | return se |
| 325 | } |
| 326 | return nil |
| 327 | } |
| 328 | if !errors.Is(de, unix.ENOENT) { |
| 329 | return de |
| 330 | } |
| 331 | if it.Done { |
| 332 | return ErrLocalJournal |
| 333 | } |
| 334 | src, err := localStat(sp, sn) |
| 335 | if err != nil { |
| 336 | return err |
| 337 | } |
| 338 | if !localSame(src, *it) { |
| 339 | return ErrLocalJournal |
| 340 | } |
| 341 | if err := unix.Renameat2(sp, sn, dp, dn, unix.RENAME_NOREPLACE); err != nil { |
| 342 | return err |
| 343 | } |
| 344 | if l.afterRename != nil { |
| 345 | return l.afterRename(it.Path) |
| 346 | } |
| 347 | return nil |
| 348 | } |
| 349 | |
amadan