init claude-code

utils/Shell.ts

@@ -0,0 +1,474 @@
+import { execFileSync, spawn } from 'child_process'
+import { constants as fsConstants, readFileSync, unlinkSync } from 'fs'
+import { type FileHandle, mkdir, open, realpath } from 'fs/promises'
+import memoize from 'lodash-es/memoize.js'
+import { isAbsolute, resolve } from 'path'
+import { join as posixJoin } from 'path/posix'
+import { logEvent } from 'src/services/analytics/index.js'
+import {
+  getOriginalCwd,
+  getSessionId,
+  setCwdState,
+} from '../bootstrap/state.js'
+import { generateTaskId } from '../Task.js'
+import { pwd } from './cwd.js'
+import { logForDebugging } from './debug.js'
+import { errorMessage, isENOENT } from './errors.js'
+import { getFsImplementation } from './fsOperations.js'
+import { logError } from './log.js'
+import {
+  createAbortedCommand,
+  createFailedCommand,
+  type ShellCommand,
+  wrapSpawn,
+} from './ShellCommand.js'
+import { getTaskOutputDir } from './task/diskOutput.js'
+import { TaskOutput } from './task/TaskOutput.js'
+import { which } from './which.js'
+
+export type { ExecResult } from './ShellCommand.js'
+
+import { accessSync } from 'fs'
+import { onCwdChangedForHooks } from './hooks/fileChangedWatcher.js'
+import { getClaudeTempDirName } from './permissions/filesystem.js'
+import { getPlatform } from './platform.js'
+import { SandboxManager } from './sandbox/sandbox-adapter.js'
+import { invalidateSessionEnvCache } from './sessionEnvironment.js'
+import { createBashShellProvider } from './shell/bashProvider.js'
+import { getCachedPowerShellPath } from './shell/powershellDetection.js'
+import { createPowerShellProvider } from './shell/powershellProvider.js'
+import type { ShellProvider, ShellType } from './shell/shellProvider.js'
+import { subprocessEnv } from './subprocessEnv.js'
+import { posixPathToWindowsPath } from './windowsPaths.js'
+
+const DEFAULT_TIMEOUT = 30 * 60 * 1000 // 30 minutes
+
+export type ShellConfig = {
+  provider: ShellProvider
+}
+
+function isExecutable(shellPath: string): boolean {
+  try {
+    accessSync(shellPath, fsConstants.X_OK)
+    return true
+  } catch (_err) {
+    // Fallback for Nix and other environments where X_OK check might fail
+    try {
+      // Try to execute the shell with --version, which should exit quickly
+      // Use execFileSync to avoid shell injection vulnerabilities
+      execFileSync(shellPath, ['--version'], {
+        timeout: 1000,
+        stdio: 'ignore',
+      })
+      return true
+    } catch {
+      return false
+    }
+  }
+}
+
+/**
+ * Determines the best available shell to use.
+ */
+export async function findSuitableShell(): Promise<string> {
+  // Check for explicit shell override first
+  const shellOverride = process.env.CLAUDE_CODE_SHELL
+  if (shellOverride) {
+    // Validate it's a supported shell type
+    const isSupported =
+      shellOverride.includes('bash') || shellOverride.includes('zsh')
+    if (isSupported && isExecutable(shellOverride)) {
+      logForDebugging(`Using shell override: ${shellOverride}`)
+      return shellOverride
+    } else {
+      // Note, if we ever want to add support for new shells here we'll need to update or Bash tool parsing to account for this
+      logForDebugging(
+        `CLAUDE_CODE_SHELL="${shellOverride}" is not a valid bash/zsh path, falling back to detection`,
+      )
+    }
+  }
+
+  // Check user's preferred shell from environment
+  const env_shell = process.env.SHELL
+  // Only consider SHELL if it's bash or zsh
+  const isEnvShellSupported =
+    env_shell && (env_shell.includes('bash') || env_shell.includes('zsh'))
+  const preferBash = env_shell?.includes('bash')
+
+  // Try to locate shells using which (uses Bun.which when available)
+  const [zshPath, bashPath] = await Promise.all([which('zsh'), which('bash')])
+
+  // Populate shell paths from which results and fallback locations
+  const shellPaths = ['/bin', '/usr/bin', '/usr/local/bin', '/opt/homebrew/bin']
+
+  // Order shells based on user preference
+  const shellOrder = preferBash ? ['bash', 'zsh'] : ['zsh', 'bash']
+  const supportedShells = shellOrder.flatMap(shell =>
+    shellPaths.map(path => `${path}/${shell}`),
+  )
+
+  // Add discovered paths to the beginning of our search list
+  // Put the user's preferred shell type first
+  if (preferBash) {
+    if (bashPath) supportedShells.unshift(bashPath)
+    if (zshPath) supportedShells.push(zshPath)
+  } else {
+    if (zshPath) supportedShells.unshift(zshPath)
+    if (bashPath) supportedShells.push(bashPath)
+  }
+
+  // Always prioritize SHELL env variable if it's a supported shell type
+  if (isEnvShellSupported && isExecutable(env_shell)) {
+    supportedShells.unshift(env_shell)
+  }
+
+  const shellPath = supportedShells.find(shell => shell && isExecutable(shell))
+
+  // If no valid shell found, throw a helpful error
+  if (!shellPath) {
+    const errorMsg =
+      'No suitable shell found. Claude CLI requires a Posix shell environment. ' +
+      'Please ensure you have a valid shell installed and the SHELL environment variable set.'
+    logError(new Error(errorMsg))
+    throw new Error(errorMsg)
+  }
+
+  return shellPath
+}
+
+async function getShellConfigImpl(): Promise<ShellConfig> {
+  const binShell = await findSuitableShell()
+  const provider = await createBashShellProvider(binShell)
+  return { provider }
+}
+
+// Memoize the entire shell config so it only happens once per session
+export const getShellConfig = memoize(getShellConfigImpl)
+
+export const getPsProvider = memoize(async (): Promise<ShellProvider> => {
+  const psPath = await getCachedPowerShellPath()
+  if (!psPath) {
+    throw new Error('PowerShell is not available')
+  }
+  return createPowerShellProvider(psPath)
+})
+
+const resolveProvider: Record<ShellType, () => Promise<ShellProvider>> = {
+  bash: async () => (await getShellConfig()).provider,
+  powershell: getPsProvider,
+}
+
+export type ExecOptions = {
+  timeout?: number
+  onProgress?: (
+    lastLines: string,
+    allLines: string,
+    totalLines: number,
+    totalBytes: number,
+    isIncomplete: boolean,
+  ) => void
+  preventCwdChanges?: boolean
+  shouldUseSandbox?: boolean
+  shouldAutoBackground?: boolean
+  /** When provided, stdout is piped (not sent to file) and this callback fires on each data chunk. */
+  onStdout?: (data: string) => void
+}
+
+/**
+ * Execute a shell command using the environment snapshot
+ * Creates a new shell process for each command execution
+ */
+export async function exec(
+  command: string,
+  abortSignal: AbortSignal,
+  shellType: ShellType,
+  options?: ExecOptions,
+): Promise<ShellCommand> {
+  const {
+    timeout,
+    onProgress,
+    preventCwdChanges,
+    shouldUseSandbox,
+    shouldAutoBackground,
+    onStdout,
+  } = options ?? {}
+  const commandTimeout = timeout || DEFAULT_TIMEOUT
+
+  const provider = await resolveProvider[shellType]()
+
+  const id = Math.floor(Math.random() * 0x10000)
+    .toString(16)
+    .padStart(4, '0')
+
+  // Sandbox temp directory - use per-user directory name to prevent multi-user permission conflicts
+  const sandboxTmpDir = posixJoin(
+    process.env.CLAUDE_CODE_TMPDIR || '/tmp',
+    getClaudeTempDirName(),
+  )
+
+  const { commandString: builtCommand, cwdFilePath } =
+    await provider.buildExecCommand(command, {
+      id,
+      sandboxTmpDir: shouldUseSandbox ? sandboxTmpDir : undefined,
+      useSandbox: shouldUseSandbox ?? false,
+    })
+
+  let commandString = builtCommand
+
+  let cwd = pwd()
+
+  // Recover if the current working directory no longer exists on disk.
+  // This can happen when a command deletes its own CWD (e.g., temp dir cleanup).
+  try {
+    await realpath(cwd)
+  } catch {
+    const fallback = getOriginalCwd()
+    logForDebugging(
+      `Shell CWD "${cwd}" no longer exists, recovering to "${fallback}"`,
+    )
+    try {
+      await realpath(fallback)
+      setCwdState(fallback)
+      cwd = fallback
+    } catch {
+      return createFailedCommand(
+        `Working directory "${cwd}" no longer exists. Please restart Claude from an existing directory.`,
+      )
+    }
+  }
+
+  // If already aborted, don't spawn the process at all
+  if (abortSignal.aborted) {
+    return createAbortedCommand()
+  }
+
+  const binShell = provider.shellPath
+
+  // Sandboxed PowerShell: wrapWithSandbox hardcodes `<binShell> -c '<cmd>'` —
+  // using pwsh there would lose -NoProfile -NonInteractive (profile load
+  // inside sandbox → delays, stray output, may hang on prompts). Instead:
+  //   • powershellProvider.buildExecCommand (useSandbox) pre-wraps as
+  //     `pwsh -NoProfile -NonInteractive -EncodedCommand <base64>` — base64
+  //     survives the runtime's shellquote.quote() layer
+  //   • pass /bin/sh as the sandbox's inner shell to exec that invocation
+  //   • outer spawn is also /bin/sh -c to parse the runtime's POSIX output
+  // /bin/sh exists on every platform where sandbox is supported.
+  const isSandboxedPowerShell = shouldUseSandbox && shellType === 'powershell'
+  const sandboxBinShell = isSandboxedPowerShell ? '/bin/sh' : binShell
+
+  if (shouldUseSandbox) {
+    commandString = await SandboxManager.wrapWithSandbox(
+      commandString,
+      sandboxBinShell,
+      undefined,
+      abortSignal,
+    )
+    // Create sandbox temp directory for sandboxed processes with secure permissions
+    try {
+      const fs = getFsImplementation()
+      await fs.mkdir(sandboxTmpDir, { mode: 0o700 })
+    } catch (error) {
+      logForDebugging(`Failed to create ${sandboxTmpDir} directory: ${error}`)
+    }
+  }
+
+  const spawnBinary = isSandboxedPowerShell ? '/bin/sh' : binShell
+  const shellArgs = isSandboxedPowerShell
+    ? ['-c', commandString]
+    : provider.getSpawnArgs(commandString)
+  const envOverrides = await provider.getEnvironmentOverrides(command)
+
+  // When onStdout is provided, use pipe mode: stdout flows through
+  // StreamWrapper → TaskOutput in-memory buffer instead of a file fd.
+  // This lets callers receive real-time stdout callbacks.
+  const usePipeMode = !!onStdout
+  const taskId = generateTaskId('local_bash')
+  const taskOutput = new TaskOutput(taskId, onProgress ?? null, !usePipeMode)
+  await mkdir(getTaskOutputDir(), { recursive: true })
+
+  // In file mode, both stdout and stderr go to the same file fd.
+  // On POSIX, O_APPEND makes each write atomic (seek-to-end + write), so
+  // stdout and stderr are interleaved chronologically without tearing.
+  // On Windows, 'a' mode strips FILE_WRITE_DATA (only grants FILE_APPEND_DATA)
+  // via libuv's fs__open. MSYS2/Cygwin probes inherited handles with
+  // NtQueryInformationFile(FileAccessInformation) and treats handles without
+  // FILE_WRITE_DATA as read-only, silently discarding all output. Using 'w'
+  // grants FILE_GENERIC_WRITE. Atomicity is preserved because duplicated
+  // handles share the same FILE_OBJECT with FILE_SYNCHRONOUS_IO_NONALERT,
+  // which serializes all I/O through a single kernel lock.
+  // SECURITY: O_NOFOLLOW prevents symlink-following attacks from the sandbox.
+  // On Windows, use string flags — numeric flags can produce EINVAL through libuv.
+  let outputHandle: FileHandle | undefined
+  if (!usePipeMode) {
+    const O_NOFOLLOW = fsConstants.O_NOFOLLOW ?? 0
+    outputHandle = await open(
+      taskOutput.path,
+      process.platform === 'win32'
+        ? 'w'
+        : fsConstants.O_WRONLY |
+            fsConstants.O_CREAT |
+            fsConstants.O_APPEND |
+            O_NOFOLLOW,
+    )
+  }
+
+  try {
+    const childProcess = spawn(spawnBinary, shellArgs, {
+      env: {
+        ...subprocessEnv(),
+        SHELL: shellType === 'bash' ? binShell : undefined,
+        GIT_EDITOR: 'true',
+        CLAUDECODE: '1',
+        ...envOverrides,
+        ...(process.env.USER_TYPE === 'ant'
+          ? {
+              CLAUDE_CODE_SESSION_ID: getSessionId(),
+            }
+          : {}),
+      },
+      cwd,
+      stdio: usePipeMode
+        ? ['pipe', 'pipe', 'pipe']
+        : ['pipe', outputHandle?.fd, outputHandle?.fd],
+      // Don't pass the signal - we'll handle termination ourselves with tree-kill
+      detached: provider.detached,
+      // Prevent visible console window on Windows (no-op on other platforms)
+      windowsHide: true,
+    })
+
+    const shellCommand = wrapSpawn(
+      childProcess,
+      abortSignal,
+      commandTimeout,
+      taskOutput,
+      shouldAutoBackground,
+    )
+
+    // Close our copy of the fd — the child has its own dup.
+    // Must happen after wrapSpawn attaches 'error' listener, since the await
+    // yields and the child's ENOENT 'error' event can fire in that window.
+    // Wrapped in its own try/catch so a close failure (e.g. EIO) doesn't fall
+    // through to the spawn-failure catch block, which would orphan the child.
+    if (outputHandle !== undefined) {
+      try {
+        await outputHandle.close()
+      } catch {
+        // fd may already be closed by the child; safe to ignore
+      }
+    }
+
+    // In pipe mode, attach the caller's callbacks alongside StreamWrapper.
+    // Both listeners receive the same data chunks (Node.js ReadableStream supports
+    // multiple 'data' listeners). StreamWrapper feeds TaskOutput for persistence;
+    // these callbacks give the caller real-time access.
+    if (childProcess.stdout && onStdout) {
+      childProcess.stdout.on('data', (chunk: string | Buffer) => {
+        onStdout(typeof chunk === 'string' ? chunk : chunk.toString())
+      })
+    }
+
+    // Attach cleanup to the command result
+    // NOTE: readFileSync/unlinkSync are intentional here — these must complete
+    // synchronously within the .then() microtask so that callers who
+    // `await shellCommand.result` see the updated cwd immediately after.
+    // Using async readFile would introduce a microtask boundary, causing
+    // a race where cwd hasn't been updated yet when the caller continues.
+
+    // On Windows, cwdFilePath is a POSIX path (for bash's `pwd -P >| $path`),
+    // but Node.js needs a native Windows path for readFileSync/unlinkSync.
+    // Similarly, `pwd -P` outputs a POSIX path that must be converted before setCwd.
+    const nativeCwdFilePath =
+      getPlatform() === 'windows'
+        ? posixPathToWindowsPath(cwdFilePath)
+        : cwdFilePath
+
+    void shellCommand.result.then(async result => {
+      // On Linux, bwrap creates 0-byte mount-point files on the host to deny
+      // writes to non-existent paths (.bashrc, HEAD, etc.). These persist after
+      // bwrap exits as ghost dotfiles in cwd. Cleanup is synchronous and a no-op
+      // on macOS. Keep before any await so callers awaiting .result see a clean
+      // working tree in the same microtask.
+      if (shouldUseSandbox) {
+        SandboxManager.cleanupAfterCommand()
+      }
+      // Only foreground tasks update the cwd
+      if (result && !preventCwdChanges && !result.backgroundTaskId) {
+        try {
+          let newCwd = readFileSync(nativeCwdFilePath, {
+            encoding: 'utf8',
+          }).trim()
+          if (getPlatform() === 'windows') {
+            newCwd = posixPathToWindowsPath(newCwd)
+          }
+          // cwd is NFC-normalized (setCwdState); newCwd from `pwd -P` may be
+          // NFD on macOS APFS. Normalize before comparing so Unicode paths
+          // don't false-positive as "changed" on every command.
+          if (newCwd.normalize('NFC') !== cwd) {
+            setCwd(newCwd, cwd)
+            invalidateSessionEnvCache()
+            void onCwdChangedForHooks(cwd, newCwd)
+          }
+        } catch {
+          logEvent('tengu_shell_set_cwd', { success: false })
+        }
+      }
+      // Clean up the temp file used for cwd tracking
+      try {
+        unlinkSync(nativeCwdFilePath)
+      } catch {
+        // File may not exist if command failed before pwd -P ran
+      }
+    })
+
+    return shellCommand
+  } catch (error) {
+    // Close the fd if spawn failed (child never got its dup)
+    if (outputHandle !== undefined) {
+      try {
+        await outputHandle.close()
+      } catch {
+        // May already be closed
+      }
+    }
+    taskOutput.clear()
+
+    logForDebugging(`Shell exec error: ${errorMessage(error)}`)
+
+    return createAbortedCommand(undefined, {
+      code: 126, // Standard Unix code for execution errors
+      stderr: errorMessage(error),
+    })
+  }
+}
+
+/**
+ * Set the current working directory
+ */
+export function setCwd(path: string, relativeTo?: string): void {
+  const resolved = isAbsolute(path)
+    ? path
+    : resolve(relativeTo || getFsImplementation().cwd(), path)
+  // Resolve symlinks to match the behavior of pwd -P.
+  // realpathSync throws ENOENT if the path doesn't exist - convert to a
+  // friendlier error message instead of a separate existsSync pre-check (TOCTOU).
+  let physicalPath: string
+  try {
+    physicalPath = getFsImplementation().realpathSync(resolved)
+  } catch (e) {
+    if (isENOENT(e)) {
+      throw new Error(`Path "${resolved}" does not exist`)
+    }
+    throw e
+  }
+
+  setCwdState(physicalPath)
+  if (process.env.NODE_ENV !== 'test') {
+    try {
+      logEvent('tengu_shell_set_cwd', {
+        success: true,
+      })
+    } catch (_error) {
+      // Ignore logging errors to prevent test failures
+    }
+  }
+}