| 1 | package taskmonitor |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "crypto/rand" |
| 6 | "crypto/sha256" |
| 7 | "encoding/hex" |
| 8 | "encoding/json" |
| 9 | "errors" |
| 10 | "fmt" |
| 11 | "os" |
| 12 | "os/exec" |
| 13 | "path/filepath" |
| 14 | "strings" |
| 15 | "time" |
| 16 | ) |
| 17 | |
| 18 | // TmuxRunner is the narrow command surface used by Adapter. Implementations |
| 19 | // must pass arguments as an array; callers never construct a shell command. |
| 20 | type TmuxRunner interface { |
| 21 | Run(ctx context.Context, args ...string) ([]byte, error) |
| 22 | } |
| 23 | |
| 24 | type execTmuxRunner struct{ binary string } |
| 25 | |
| 26 | func (r execTmuxRunner) Run(ctx context.Context, args ...string) ([]byte, error) { |
| 27 | cmd := exec.CommandContext(ctx, r.binary, args...) |
| 28 | return cmd.Output() |
| 29 | } |
| 30 | |
| 31 | // Mapping records only resources created by this adapter. |
| 32 | type TmuxMapping struct { |
| 33 | SchemaVersion int `json:"schema_version"` |
| 34 | TaskID string `json:"task_id"` |
| 35 | ProjectDir string `json:"project_dir"` |
| 36 | Session string `json:"session"` |
| 37 | Window string `json:"window"` |
| 38 | Pane string `json:"pane"` |
| 39 | OwnerToken string `json:"owner_token,omitempty"` |
| 40 | CreatedAt time.Time `json:"created_at"` |
| 41 | Stale bool `json:"stale"` |
| 42 | } |
| 43 | |
| 44 | type TmuxResult struct { |
| 45 | SchemaVersion int `json:"schema_version"` |
| 46 | TaskID string `json:"task_id"` |
| 47 | Available bool `json:"available"` |
| 48 | Idempotent bool `json:"idempotent"` |
| 49 | Mapping *TmuxMapping `json:"mapping,omitempty"` |
| 50 | Error *CtrlError `json:"error,omitempty"` |
| 51 | } |
| 52 | |
| 53 | // TmuxAdapter maps tasks to user-visible tmux windows. It never changes task |
| 54 | // state; the Task Store remains the sole source of truth. |
| 55 | type TmuxAdapter struct { |
| 56 | store Store |
| 57 | runner TmuxRunner |
| 58 | base string |
| 59 | } |
| 60 | |
| 61 | func NewTmuxAdapter(store Store, baseDir string) *TmuxAdapter { |
| 62 | return &TmuxAdapter{store: store, runner: newDefaultTmuxRunner(), base: baseDir} |
| 63 | } |
| 64 | |
| 65 | func NewTmuxAdapterWithRunner(store Store, baseDir string, runner TmuxRunner) *TmuxAdapter { |
| 66 | return &TmuxAdapter{store: store, runner: runner, base: baseDir} |
| 67 | } |
| 68 | |
| 69 | func newDefaultTmuxRunner() TmuxRunner { |
| 70 | path, err := exec.LookPath("tmux") |
| 71 | if err != nil { |
| 72 | return nil |
| 73 | } |
| 74 | return execTmuxRunner{binary: path} |
| 75 | } |
| 76 | |
| 77 | func (a *TmuxAdapter) Attach(ctx context.Context, projectDir, taskID, requestedSession string) TmuxResult { |
| 78 | if err := validateTmuxName(requestedSession); err != nil { |
| 79 | return tmuxError(taskID, ErrTmuxInvalidName, err.Error()) |
| 80 | } |
| 81 | snap, err := a.store.GetTask(ctx, projectDir, taskID) |
| 82 | if err != nil { |
| 83 | return tmuxError(taskID, ErrTmuxTaskError, "task lookup failed") |
| 84 | } |
| 85 | if snap == nil { |
| 86 | return tmuxError(taskID, ErrTaskNotFound, "task not found") |
| 87 | } |
| 88 | if a.runner == nil { |
| 89 | return tmuxUnavailable(taskID) |
| 90 | } |
| 91 | old, err := a.load(projectDir, taskID) |
| 92 | if err != nil { |
| 93 | return tmuxError(taskID, ErrTmuxMappingFailed, "mapping read failed") |
| 94 | } |
| 95 | if old != nil { |
| 96 | if err := a.validateMapping(projectDir, taskID, old); err != nil { |
| 97 | if err := a.removeMapping(projectDir, taskID); err != nil { |
| 98 | return tmuxError(taskID, ErrTmuxMappingFailed, "invalid mapping removal failed") |
| 99 | } |
| 100 | } else if !old.Stale && a.ownsSession(ctx, old) { |
| 101 | return TmuxResult{SchemaVersion: 1, TaskID: taskID, Available: true, Idempotent: true, Mapping: old} |
| 102 | } else { |
| 103 | old.Stale = true |
| 104 | if err := a.save(projectDir, *old); err != nil { |
| 105 | return tmuxError(taskID, ErrTmuxMappingFailed, "mapping update failed") |
| 106 | } |
| 107 | } |
| 108 | } |
| 109 | session := requestedSession |
| 110 | if session == "" { |
| 111 | session = defaultTmuxSessionName(taskID) |
| 112 | } |
| 113 | if err := validateTmuxName(session); err != nil { |
| 114 | return tmuxError(taskID, ErrTmuxInvalidName, err.Error()) |
| 115 | } |
| 116 | ownerToken, err := newTmuxOwnerToken() |
| 117 | if err != nil { |
| 118 | return tmuxError(taskID, ErrTmuxMappingFailed, "mapping ownership creation failed") |
| 119 | } |
| 120 | window := "task" |
| 121 | if _, err := a.runner.Run(ctx, "new-session", "-d", "-s", session, "-n", window); err != nil { |
| 122 | return tmuxError(taskID, ErrTmuxCommandFailed, "tmux session creation failed") |
| 123 | } |
| 124 | m := &TmuxMapping{SchemaVersion: 1, TaskID: taskID, ProjectDir: projectDir, Session: session, Window: window, Pane: session + ":" + window + ".0", OwnerToken: ownerToken, CreatedAt: time.Now().UTC()} |
| 125 | if _, err := a.runner.Run(ctx, "set-option", "-t", tmuxSessionPaneTarget(session), tmuxOwnerOption, ownerToken); err != nil { |
| 126 | // set-option may have reached the tmux server even when the client |
| 127 | // reports an error. Clean up only through the ownership-checked command. |
| 128 | _ = a.killOwnedSession(ctx, m) |
| 129 | return tmuxError(taskID, ErrTmuxCommandFailed, "tmux ownership marker failed") |
| 130 | } |
| 131 | if err := a.save(projectDir, *m); err != nil { |
| 132 | _ = a.killOwnedSession(ctx, m) |
| 133 | return tmuxError(taskID, ErrTmuxMappingFailed, "mapping write failed") |
| 134 | } |
| 135 | return TmuxResult{SchemaVersion: 1, TaskID: taskID, Available: true, Mapping: m} |
| 136 | } |
| 137 | |
| 138 | func (a *TmuxAdapter) Status(ctx context.Context, projectDir, taskID string) TmuxResult { |
| 139 | m, err := a.load(projectDir, taskID) |
| 140 | if err != nil { |
| 141 | return tmuxError(taskID, ErrTmuxMappingFailed, "mapping read failed") |
| 142 | } |
| 143 | if m == nil { |
| 144 | return TmuxResult{SchemaVersion: 1, TaskID: taskID, Available: a.runner != nil} |
| 145 | } |
| 146 | if err := a.validateMapping(projectDir, taskID, m); err != nil { |
| 147 | return tmuxError(taskID, ErrTmuxMappingFailed, "mapping ownership validation failed") |
| 148 | } |
| 149 | if a.runner == nil { |
| 150 | m.Stale = true |
| 151 | return TmuxResult{SchemaVersion: 1, TaskID: taskID, Available: false, Mapping: m} |
| 152 | } |
| 153 | if !a.ownsSession(ctx, m) { |
| 154 | m.Stale = true |
| 155 | if err := a.save(projectDir, *m); err != nil { |
| 156 | return tmuxError(taskID, ErrTmuxMappingFailed, "mapping update failed") |
| 157 | } |
| 158 | } |
| 159 | return TmuxResult{SchemaVersion: 1, TaskID: taskID, Available: true, Mapping: m} |
| 160 | } |
| 161 | |
| 162 | func (a *TmuxAdapter) Open(ctx context.Context, projectDir, taskID string) TmuxResult { |
| 163 | r := a.Status(ctx, projectDir, taskID) |
| 164 | if r.Mapping == nil || r.Mapping.Stale { |
| 165 | return r |
| 166 | } |
| 167 | if a.runner == nil { |
| 168 | return tmuxUnavailable(taskID) |
| 169 | } |
| 170 | if _, err := a.runner.Run(ctx, "switch-client", "-t", r.Mapping.Pane); err != nil { |
| 171 | r.Error = &CtrlError{Code: ErrTmuxCommandFailed, Message: "tmux open failed"} |
| 172 | } |
| 173 | return r |
| 174 | } |
| 175 | |
| 176 | func (a *TmuxAdapter) Detach(ctx context.Context, projectDir, taskID string) TmuxResult { |
| 177 | m, err := a.load(projectDir, taskID) |
| 178 | if err != nil { |
| 179 | return tmuxError(taskID, ErrTmuxMappingFailed, "mapping read failed") |
| 180 | } |
| 181 | if m == nil { |
| 182 | return TmuxResult{SchemaVersion: 1, TaskID: taskID, Available: a.runner != nil, Idempotent: true} |
| 183 | } |
| 184 | if err := a.validateMapping(projectDir, taskID, m); err != nil { |
| 185 | if err := a.removeMapping(projectDir, taskID); err != nil { |
| 186 | return tmuxError(taskID, ErrTmuxMappingFailed, "invalid mapping removal failed") |
| 187 | } |
| 188 | return tmuxError(taskID, ErrTmuxMappingFailed, "mapping ownership validation failed") |
| 189 | } |
| 190 | if a.runner != nil && !m.Stale { |
| 191 | if a.ownsSession(ctx, m) { |
| 192 | if err := a.killOwnedSession(ctx, m); err != nil && a.ownsSession(ctx, m) { |
| 193 | return tmuxError(taskID, ErrTmuxCommandFailed, "tmux detach failed") |
| 194 | } |
| 195 | if a.ownsSession(ctx, m) { |
| 196 | return tmuxError(taskID, ErrTmuxCommandFailed, "tmux detach failed") |
| 197 | } |
| 198 | } else { |
| 199 | m.Stale = true |
| 200 | } |
| 201 | } |
| 202 | if err := a.removeMapping(projectDir, taskID); err != nil { |
| 203 | return tmuxError(taskID, ErrTmuxMappingFailed, "mapping removal failed") |
| 204 | } |
| 205 | return TmuxResult{SchemaVersion: 1, TaskID: taskID, Available: a.runner != nil, Idempotent: false, Mapping: m} |
| 206 | } |
| 207 | |
| 208 | const ( |
| 209 | tmuxOwnerOption = "@reasonix-owner" |
| 210 | tmuxOwnerTokenBytes = 16 |
| 211 | defaultTmuxNamePrefix = "reasonix-" |
| 212 | |
| 213 | ErrTmuxUnavailable = "tmux_unavailable" |
| 214 | ErrTmuxInvalidName = "tmux_invalid_name" |
| 215 | ErrTmuxCommandFailed = "tmux_command_failed" |
| 216 | ErrTmuxMappingFailed = "tmux_mapping_failed" |
| 217 | ErrTmuxTaskError = "tmux_task_error" |
| 218 | ) |
| 219 | |
| 220 | func defaultTmuxSessionName(taskID string) string { |
| 221 | candidate := defaultTmuxNamePrefix + taskID |
| 222 | if len(candidate) <= 64 { |
| 223 | return candidate |
| 224 | } |
| 225 | sum := sha256.Sum256([]byte(taskID)) |
| 226 | return defaultTmuxNamePrefix + hex.EncodeToString(sum[:16]) |
| 227 | } |
| 228 | |
| 229 | func newTmuxOwnerToken() (string, error) { |
| 230 | raw := make([]byte, tmuxOwnerTokenBytes) |
| 231 | if _, err := rand.Read(raw); err != nil { |
| 232 | return "", err |
| 233 | } |
| 234 | return hex.EncodeToString(raw), nil |
| 235 | } |
| 236 | |
| 237 | func tmuxUnavailable(taskID string) TmuxResult { |
| 238 | return tmuxError(taskID, ErrTmuxUnavailable, "tmux is not available") |
| 239 | } |
| 240 | |
| 241 | func tmuxError(taskID, code, message string) TmuxResult { |
| 242 | return TmuxResult{SchemaVersion: 1, TaskID: taskID, Error: &CtrlError{Code: code, Message: message}} |
| 243 | } |
| 244 | |
| 245 | func validateTmuxName(name string) error { |
| 246 | if name == "" { |
| 247 | return nil |
| 248 | } |
| 249 | if len(name) > 64 { |
| 250 | return errors.New("tmux name contains invalid characters") |
| 251 | } |
| 252 | for _, r := range name { |
| 253 | if !((r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z') || (r >= '0' && r <= '9') || r == '-' || r == '_' || r == '.') { |
| 254 | return errors.New("tmux name contains invalid characters") |
| 255 | } |
| 256 | } |
| 257 | return nil |
| 258 | } |
| 259 | |
| 260 | func (a *TmuxAdapter) validateMapping(projectDir, taskID string, m *TmuxMapping) error { |
| 261 | if m == nil || m.SchemaVersion != 1 || m.TaskID != taskID { |
| 262 | return errors.New("tmux mapping identity mismatch") |
| 263 | } |
| 264 | if err := validateTmuxName(m.Session); err != nil || m.Session == "" || m.Window != "task" || m.Pane != m.Session+":"+m.Window+".0" { |
| 265 | return errors.New("tmux mapping target is invalid") |
| 266 | } |
| 267 | if len(m.OwnerToken) != tmuxOwnerTokenBytes*2 { |
| 268 | return errors.New("tmux mapping owner token is missing") |
| 269 | } |
| 270 | if _, err := hex.DecodeString(m.OwnerToken); err != nil { |
| 271 | return errors.New("tmux mapping owner token is invalid") |
| 272 | } |
| 273 | wantRoot, err := NewFileStore(a.base).taskRoot(projectDir) |
| 274 | if err != nil { |
| 275 | return err |
| 276 | } |
| 277 | gotRoot, err := NewFileStore(a.base).taskRoot(m.ProjectDir) |
| 278 | if err != nil { |
| 279 | return err |
| 280 | } |
| 281 | wantRoot, err = filepath.Abs(wantRoot) |
| 282 | if err != nil { |
| 283 | return err |
| 284 | } |
| 285 | gotRoot, err = filepath.Abs(gotRoot) |
| 286 | if err != nil { |
| 287 | return err |
| 288 | } |
| 289 | if filepath.Clean(gotRoot) != filepath.Clean(wantRoot) { |
| 290 | return errors.New("tmux mapping project mismatch") |
| 291 | } |
| 292 | return nil |
| 293 | } |
| 294 | |
| 295 | func (a *TmuxAdapter) ownsSession(ctx context.Context, m *TmuxMapping) bool { |
| 296 | if a.runner == nil || m == nil { |
| 297 | return false |
| 298 | } |
| 299 | out, err := a.runner.Run(ctx, "show-options", "-v", "-t", tmuxSessionPaneTarget(m.Session), tmuxOwnerOption) |
| 300 | return err == nil && strings.TrimSpace(string(out)) == m.OwnerToken |
| 301 | } |
| 302 | |
| 303 | // killOwnedSession performs the ownership comparison and destructive action in |
| 304 | // one tmux server command queue. A separate show-options + kill-session pair |
| 305 | // would allow the named session to be replaced between the check and the kill. |
| 306 | func (a *TmuxAdapter) killOwnedSession(ctx context.Context, m *TmuxMapping) error { |
| 307 | if a.runner == nil || m == nil { |
| 308 | return nil |
| 309 | } |
| 310 | condition := fmt.Sprintf("#{==:#{%s},%s}", tmuxOwnerOption, m.OwnerToken) |
| 311 | killCommand := "kill-session -t =" + m.Session |
| 312 | _, err := a.runner.Run(ctx, "if-shell", "-t", tmuxSessionPaneTarget(m.Session), "-F", condition, killCommand, "") |
| 313 | return err |
| 314 | } |
| 315 | |
| 316 | func tmuxSessionPaneTarget(session string) string { |
| 317 | return "=" + session + ":" |
| 318 | } |
| 319 | |
| 320 | func (a *TmuxAdapter) removeMapping(projectDir, taskID string) error { |
| 321 | path, err := a.mappingPath(projectDir, taskID) |
| 322 | if err != nil { |
| 323 | return err |
| 324 | } |
| 325 | if err := os.Remove(path); err != nil && !os.IsNotExist(err) { |
| 326 | return fmt.Errorf("remove tmux mapping: %w", err) |
| 327 | } |
| 328 | return nil |
| 329 | } |
| 330 | |
| 331 | func (a *TmuxAdapter) mappingPath(projectDir, taskID string) (string, error) { |
| 332 | id, err := safeID(taskID) |
| 333 | if err != nil { |
| 334 | return "", err |
| 335 | } |
| 336 | root, err := NewFileStore(a.base).taskRoot(projectDir) |
| 337 | if err != nil { |
| 338 | return "", err |
| 339 | } |
| 340 | path := filepath.Join(root, ".tmux", id+".json") |
| 341 | if err := rejectSymlinkChain(root, path); err != nil { |
| 342 | return "", err |
| 343 | } |
| 344 | return path, nil |
| 345 | } |
| 346 | |
| 347 | func (a *TmuxAdapter) load(projectDir, taskID string) (*TmuxMapping, error) { |
| 348 | path, err := a.mappingPath(projectDir, taskID) |
| 349 | if err != nil { |
| 350 | return nil, err |
| 351 | } |
| 352 | b, err := os.ReadFile(path) |
| 353 | if os.IsNotExist(err) { |
| 354 | return nil, nil |
| 355 | } |
| 356 | if err != nil { |
| 357 | return nil, err |
| 358 | } |
| 359 | var m TmuxMapping |
| 360 | if err := json.Unmarshal(b, &m); err != nil { |
| 361 | return nil, err |
| 362 | } |
| 363 | return &m, nil |
| 364 | } |
| 365 | |
| 366 | func (a *TmuxAdapter) save(projectDir string, m TmuxMapping) error { |
| 367 | path, err := a.mappingPath(projectDir, m.TaskID) |
| 368 | if err != nil { |
| 369 | return err |
| 370 | } |
| 371 | root, err := NewFileStore(a.base).taskRoot(projectDir) |
| 372 | if err != nil { |
| 373 | return err |
| 374 | } |
| 375 | if _, err := prepareTaskDir(root, ".tmux"); err != nil { |
| 376 | return err |
| 377 | } |
| 378 | b, err := json.Marshal(m) |
| 379 | if err != nil { |
| 380 | return err |
| 381 | } |
| 382 | tmp, err := os.CreateTemp(filepath.Dir(path), ".tmux-*.tmp") |
| 383 | if err != nil { |
| 384 | return err |
| 385 | } |
| 386 | name := tmp.Name() |
| 387 | defer os.Remove(name) |
| 388 | if _, err = tmp.Write(b); err != nil { |
| 389 | _ = tmp.Close() |
| 390 | return err |
| 391 | } |
| 392 | if err = tmp.Sync(); err != nil { |
| 393 | _ = tmp.Close() |
| 394 | return err |
| 395 | } |
| 396 | if err = tmp.Close(); err != nil { |
| 397 | return err |
| 398 | } |
| 399 | if err = os.Rename(name, path); err != nil { |
| 400 | return err |
| 401 | } |
| 402 | return nil |
| 403 | } |
| 404 |