bare-operating-system/kernel/bin/getfacl

/* BARE_OS_BIN_API 1.0.0 — bump when staged /bin script semantics change (see developer guide). */
/** Shared helpers for drive-resident /bin scripts (prepended before each command). */
function bareStdin(ctx) {
  return typeof ctx.shellStdin === 'string' ? ctx.shellStdin : ''
}

/** @param {number} mode @param {'file' | 'directory' | 'symlink'} type */
function bareFormatModeString(mode, type) {
  const typeChar = type === 'directory' ? 'd' : type === 'symlink' ? 'l' : '-'
  const perm = mode & 0o777
  const r = (bit) => (perm & bit ? 'r' : '-')
  const w = (bit) => (perm & bit ? 'w' : '-')
  const x = (bit) => (perm & bit ? 'x' : '-')
  return (
    typeChar +
    r(0o400) +
    w(0o200) +
    x(0o100) +
    r(0o040) +
    w(0o020) +
    x(0o010) +
    r(0o004) +
    w(0o002) +
    x(0o001)
  )
}

/** @param {number} mtimeMs @param {number} [nowMs] */
function bareFormatLsMtime(mtimeMs, nowMs) {
  const now = nowMs != null ? nowMs : Date.now()
  const d = new Date(mtimeMs)
  const months = [
    'Jan',
    'Feb',
    'Mar',
    'Apr',
    'May',
    'Jun',
    'Jul',
    'Aug',
    'Sep',
    'Oct',
    'Nov',
    'Dec'
  ]
  const mon = months[d.getMonth()]
  const day = String(d.getDate()).padStart(2, ' ')
  const sixMo = 180 * 24 * 3600 * 1000
  if (Math.abs(now - mtimeMs) > sixMo) {
    const yr = String(d.getFullYear()).padStart(4, ' ')
    return mon + ' ' + day + '  ' + yr
  }
  const hh = String(d.getHours()).padStart(2, '0')
  const mm = String(d.getMinutes()).padStart(2, '0')
  return mon + ' ' + day + ' ' + hh + ':' + mm
}

/** @param {number} size */
function barePosixBlocks(size) {
  return Math.ceil(Number(size) / 512) || 0
}

/**
 * Raw stdout for NUL/binary when **`process.stdout.write`** is missing.
 * If **`ctx.bareOsBinWrite(Uint8Array|string)`** is set (tests / host), use it.
 * @param {Record<string, unknown>} ctx
 * @param {string | Uint8Array} chunk
 * @returns {boolean}
 */
function bareOsEmitRaw(ctx, chunk) {
  if (typeof ctx.bareOsBinWrite === 'function') {
    const b4 = ctx.b4a
    const u8 =
      typeof chunk === 'string'
        ? b4 && typeof b4.from === 'function'
          ? b4.from(chunk)
          : new TextEncoder().encode(chunk)
        : chunk
    ctx.bareOsBinWrite(u8 instanceof Uint8Array ? u8 : new Uint8Array(u8))
    return true
  }
  const w = globalThis.process?.stdout?.write
  if (typeof w === 'function') {
    w.call(globalThis.process.stdout, chunk)
    return true
  }
  return false
}

/**
 * getfacl — show POSIX-style ACL text for a VFS path.
 * When PATH.bare_acl exists, prints that file; otherwise synthesizes user/group/other
 * triples from the path mode bits (see setfacl / handbook).
 */

/**
 * @param {number} mode
 * @param {number} shift
 */
function tripleFromMode(mode, shift) {
  const b = (mode >> shift) & 7
  const r = b & 4 ? 'r' : '-'
  const w = b & 2 ? 'w' : '-'
  const x = b & 1 ? 'x' : '-'
  return r + w + x
}

async function run(ctx, argv) {
  let compact = false
  /** @type {string[]} */
  const files = []
  for (let i = 1; i < argv.length; i++) {
    const a = argv[i]
    if (a === '-c' || a === '--compact') {
      compact = true
      continue
    }
    if (a === '--help' || a === '-h') {
      ctx.console.log('usage: getfacl [-c] FILE')
      return
    }
    if (a.startsWith('-')) {
      ctx.console.error('getfacl: unsupported option ' + a)
      ctx.exitCode = 1
      return
    }
    files.push(a)
  }
  if (files.length !== 1) {
    ctx.console.error('usage: getfacl [-c] FILE')
    ctx.exitCode = 1
    return
  }
  const path = files[0]
  const side = path + '.bare_acl'
  try {
    const st = await ctx.vfs.stat(path)
    if (!st) {
      ctx.console.error('getfacl: ' + path + ': No such file')
      ctx.exitCode = 1
      return
    }
    const raw = await ctx.vfs.readFile(side)
    if (raw && raw.byteLength) {
      const text = ctx.b4a.toString(raw)
      ctx.console.log(text.replace(/\n$/, ''))
      return
    }
    const mode = (st.mode || 0) & 0o777
    const u = tripleFromMode(mode, 6)
    const g = tripleFromMode(mode, 3)
    const o = tripleFromMode(mode, 0)
    const lines = compact
      ? ['user::' + u, 'group::' + g, 'other::' + o]
      : [
          '# file: ' + path,
          '# owner: synthetic',
          '# group: synthetic',
          'user::' + u,
          'group::' + g,
          'other::' + o
        ]
    ctx.console.log(lines.join('\n'))
  } catch (e) {
    ctx.console.error(
      'getfacl: ' + path + ': ' + (e && e.message ? e.message : String(e))
    )
    ctx.exitCode = 1
  }
}