bare-operating-system/packages/bare-os-seeder/kernel/bin/chmod

/* 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
}

function bareChmodSymbolic(curPerm, spec) {
  let m = curPerm & 0o777
  const parts = spec.split(',')
  for (const raw of parts) {
    const part = raw.trim()
    if (!part) continue
    let who = 0
    let i = 0
    while (i < part.length && 'augo'.includes(part[i])) {
      const c = part[i++]
      if (c === 'a') who |= 0o777
      if (c === 'u') who |= 0o700
      if (c === 'g') who |= 0o070
      if (c === 'o') who |= 0o007
    }
    if (!who) who = 0o777
    const op = part[i++]
    if (!op || !'+-='.includes(op)) continue
    const rest = part.slice(i)
    let bits = 0
    let wantX = false
    for (const ch of rest) {
      if (ch === 'r') bits |= who & 0o444
      if (ch === 'w') bits |= who & 0o222
      if (ch === 'x' || ch === 's' || ch === 't') bits |= who & 0o111
      if (ch === 'X') wantX = true
    }
    if (wantX && m & 0o111) bits |= who & 0o111
    if (op === '=') m = (m & ~who) | bits
    else if (op === '+') m |= bits
    else if (op === '-') m &= ~bits
  }
  return m
}

async function run(ctx, argv) {
  const modeStr = argv[1]
  const files = argv.slice(2)
  if (!modeStr || !files.length) {
    ctx.console.error(
      'usage: chmod MODE FILE...\n       MODE is octal (e.g. 644) or symbolic (e.g. u+rw)'
    )
    ctx.exitCode = 1
    return
  }
  const sym = !/^[0-7]+$/.test(modeStr)
  for (const f of files) {
    try {
      let perm
      if (sym) {
        const st = await ctx.vfs.stat(f)
        if (!st) {
          ctx.console.error('chmod: ' + f + ': No such file')
          ctx.exitCode = 1
          continue
        }
        perm = bareChmodSymbolic(st.mode & 0o777, modeStr)
      } else {
        perm = Number.parseInt(String(modeStr), 8)
        if (!Number.isFinite(perm) || perm < 0) {
          ctx.console.error('chmod: invalid mode')
          ctx.exitCode = 1
          return
        }
        perm &= 0o777
      }
      await ctx.vfs.chmod(f, perm)
    } catch (e) {
      ctx.console.error('chmod: ' + f + ': ' + (e.message || e))
      ctx.exitCode = 1
    }
  }
}