| 1 | #!/usr/bin/env python2
|
| 2 | from __future__ import print_function
|
| 3 |
|
| 4 | from signal import SIG_DFL, SIG_IGN, SIGINT, SIGWINCH
|
| 5 |
|
| 6 | from _devbuild.gen import arg_types
|
| 7 | from _devbuild.gen.runtime_asdl import cmd_value
|
| 8 | from _devbuild.gen.syntax_asdl import loc, loc_t, source, command_e, command
|
| 9 | from core import alloc
|
| 10 | from core import dev
|
| 11 | from core import error
|
| 12 | from core import main_loop
|
| 13 | from core import vm
|
| 14 | from frontend import flag_util
|
| 15 | from frontend import reader
|
| 16 | from frontend import signal_def
|
| 17 | from frontend import typed_args
|
| 18 | from builtin import process_osh # for PrintSignals()
|
| 19 | from data_lang import j8_lite
|
| 20 | from mycpp import iolib
|
| 21 | from mycpp import mylib
|
| 22 | from mycpp.mylib import iteritems, print_stderr, log
|
| 23 |
|
| 24 | from typing import Dict, List, Optional, TYPE_CHECKING, cast
|
| 25 | if TYPE_CHECKING:
|
| 26 | from _devbuild.gen.syntax_asdl import command_t
|
| 27 | from core import optview
|
| 28 | from display import ui
|
| 29 | from frontend import args
|
| 30 | from frontend.parse_lib import ParseContext
|
| 31 |
|
| 32 | _ = log
|
| 33 |
|
| 34 |
|
| 35 | class TrapState(object):
|
| 36 | """Traps are shell callbacks that the user wants to run on certain events.
|
| 37 |
|
| 38 | There are 2 catogires:
|
| 39 | 1. Signals like SIGUSR1
|
| 40 | 2. Hooks like EXIT
|
| 41 |
|
| 42 | Signal handlers execute in the main loop, and within blocking syscalls.
|
| 43 |
|
| 44 | EXIT, DEBUG, ERR, RETURN execute in specific places in the interpreter.
|
| 45 | """
|
| 46 |
|
| 47 | def __init__(self, signal_safe):
|
| 48 | # type: (iolib.SignalSafe) -> None
|
| 49 | self.signal_safe = signal_safe
|
| 50 | self.hooks = {} # type: Dict[str, command_t]
|
| 51 | self.traps = {} # type: Dict[int, command_t]
|
| 52 |
|
| 53 | def ClearForSubProgram(self, inherit_errtrace):
|
| 54 | # type: (bool) -> None
|
| 55 | """SubProgramThunk uses this because traps aren't inherited."""
|
| 56 |
|
| 57 | # bash clears hooks like DEBUG in subshells.
|
| 58 | # The ERR can be preserved if set -o errtrace
|
| 59 | hook_err = self.hooks.get('ERR')
|
| 60 | self.hooks.clear()
|
| 61 | if hook_err is not None and inherit_errtrace:
|
| 62 | self.hooks['ERR'] = hook_err
|
| 63 |
|
| 64 | self.traps.clear()
|
| 65 |
|
| 66 | def GetHook(self, hook_name):
|
| 67 | # type: (str) -> command_t
|
| 68 | """ e.g. EXIT hook. """
|
| 69 | return self.hooks.get(hook_name, None)
|
| 70 |
|
| 71 | def GetTrap(self, sig_num):
|
| 72 | # type: (int) -> command_t
|
| 73 | return self.traps.get(sig_num, None)
|
| 74 |
|
| 75 | def _AddUserTrap(self, sig_num, handler):
|
| 76 | # type: (int, command_t) -> None
|
| 77 | """ e.g. SIGUSR1 """
|
| 78 | self.traps[sig_num] = handler
|
| 79 |
|
| 80 | if handler.tag() == command_e.NoOp:
|
| 81 | if sig_num == SIGINT:
|
| 82 | self.signal_safe.SetSigIntTrapped(False)
|
| 83 | elif sig_num == SIGWINCH:
|
| 84 | self.signal_safe.SetSigWinchCode(iolib.UNTRAPPED_SIGWINCH)
|
| 85 | else:
|
| 86 | iolib.sigaction(sig_num, SIG_IGN)
|
| 87 | else:
|
| 88 | if sig_num == SIGINT:
|
| 89 | # Don't disturb the underlying runtime's SIGINT handllers
|
| 90 | # 1. CPython has one for KeyboardInterrupt
|
| 91 | # 2. mycpp runtime simulates KeyboardInterrupt:
|
| 92 | # pyos::InitSignalSafe() calls RegisterSignalInterest(SIGINT),
|
| 93 | # then we PollSigInt() in the osh/cmd_eval.py main loop
|
| 94 | self.signal_safe.SetSigIntTrapped(True)
|
| 95 | elif sig_num == SIGWINCH:
|
| 96 | self.signal_safe.SetSigWinchCode(SIGWINCH)
|
| 97 | else:
|
| 98 | iolib.RegisterSignalInterest(sig_num)
|
| 99 |
|
| 100 | def _RemoveUserTrap(self, sig_num):
|
| 101 | # type: (int) -> None
|
| 102 |
|
| 103 | mylib.dict_erase(self.traps, sig_num)
|
| 104 |
|
| 105 | if sig_num == SIGINT:
|
| 106 | self.signal_safe.SetSigIntTrapped(False)
|
| 107 | elif sig_num == SIGWINCH:
|
| 108 | self.signal_safe.SetSigWinchCode(iolib.UNTRAPPED_SIGWINCH)
|
| 109 | else:
|
| 110 | # TODO: In process.InitInteractiveShell(), 4 signals are set to
|
| 111 | # SIG_IGN, not SIG_DFL:
|
| 112 | #
|
| 113 | # SIGQUIT SIGTSTP SIGTTOU SIGTTIN
|
| 114 | #
|
| 115 | # Should we restore them? It's rare that you type 'trap' in
|
| 116 | # interactive shells, but it might be more correct. See what other
|
| 117 | # shells do.
|
| 118 | iolib.sigaction(sig_num, SIG_DFL)
|
| 119 |
|
| 120 | def AddItem(self, parsed_id, handler):
|
| 121 | # type: (str, command_t) -> None
|
| 122 | """Add trap or hook, parsed to EXIT or INT (not 0 or SIGINT)"""
|
| 123 | if parsed_id in _HOOK_NAMES:
|
| 124 | self.hooks[parsed_id] = handler
|
| 125 | else:
|
| 126 | sig_num = signal_def.GetNumber(parsed_id)
|
| 127 | # Should have already been validated
|
| 128 | assert sig_num is not signal_def.NO_SIGNAL
|
| 129 |
|
| 130 | self._AddUserTrap(sig_num, handler)
|
| 131 |
|
| 132 | def RemoveItem(self, parsed_id):
|
| 133 | # type: (str) -> None
|
| 134 | """Remove trap or hook, parsed to EXIT or INT (not 0 or SIGINT)"""
|
| 135 | if parsed_id in _HOOK_NAMES:
|
| 136 | mylib.dict_erase(self.hooks, parsed_id)
|
| 137 | else:
|
| 138 | sig_num = signal_def.GetNumber(parsed_id)
|
| 139 | # Should have already been validated
|
| 140 | assert sig_num is not signal_def.NO_SIGNAL
|
| 141 |
|
| 142 | self._RemoveUserTrap(sig_num)
|
| 143 |
|
| 144 | def GetPendingTraps(self):
|
| 145 | # type: () -> Optional[List[command_t]]
|
| 146 | """Transfer ownership of queue of pending trap handlers to caller."""
|
| 147 | signals = self.signal_safe.TakePendingSignals()
|
| 148 | if 0:
|
| 149 | log('*** GetPendingTraps')
|
| 150 | for si in signals:
|
| 151 | log('SIGNAL %d', si)
|
| 152 | #import traceback
|
| 153 | #traceback.print_stack()
|
| 154 |
|
| 155 | # Optimization for the common case: do not allocate a list. This function
|
| 156 | # is called in the interpreter loop.
|
| 157 | if len(signals) == 0:
|
| 158 | self.signal_safe.ReuseEmptyList(signals)
|
| 159 | return None
|
| 160 |
|
| 161 | run_list = [] # type: List[command_t]
|
| 162 | for sig_num in signals:
|
| 163 | node = self.traps.get(sig_num, None)
|
| 164 | if node is not None:
|
| 165 | run_list.append(node)
|
| 166 |
|
| 167 | # Optimization to avoid allocation in the main loop.
|
| 168 | del signals[:]
|
| 169 | self.signal_safe.ReuseEmptyList(signals)
|
| 170 |
|
| 171 | return run_list
|
| 172 |
|
| 173 | def ThisProcessHasTraps(self):
|
| 174 | # type: () -> bool
|
| 175 | """
|
| 176 | noforklast optimizations are not enabled when the process has code to
|
| 177 | run after fork!
|
| 178 | """
|
| 179 | if 0:
|
| 180 | log('traps %d', len(self.traps))
|
| 181 | log('hooks %d', len(self.hooks))
|
| 182 | return len(self.traps) != 0 or len(self.hooks) != 0
|
| 183 |
|
| 184 |
|
| 185 | _HOOK_NAMES = ['EXIT', 'ERR', 'RETURN', 'DEBUG']
|
| 186 |
|
| 187 |
|
| 188 | def _ParseSignalOrHook(user_str, blame_loc, allow_legacy=True):
|
| 189 | # type: (str, loc_t, bool) -> str
|
| 190 | """Convert user string to a parsed/normalized string.
|
| 191 |
|
| 192 | These can be passed to AddItem() and RemoveItem()
|
| 193 |
|
| 194 | See unit tests in builtin/trap_osh_test.py
|
| 195 | '0' -> 'EXIT'
|
| 196 | 'EXIT' -> 'EXIT'
|
| 197 | 'eXIT' -> 'EXIT'
|
| 198 |
|
| 199 | '2' -> 'INT'
|
| 200 | 'iNT' -> 'INT'
|
| 201 | 'sIGINT' -> 'INT'
|
| 202 |
|
| 203 | 'zz' -> error
|
| 204 | '-150' -> error
|
| 205 | '10000' -> error
|
| 206 | """
|
| 207 | if allow_legacy and user_str.isdigit():
|
| 208 | try:
|
| 209 | sig_num = int(user_str)
|
| 210 | except ValueError:
|
| 211 | raise error.Usage("got overflowing integer: %s" % user_str,
|
| 212 | blame_loc)
|
| 213 |
|
| 214 | if sig_num == 0: # Special case
|
| 215 | return 'EXIT'
|
| 216 |
|
| 217 | name = signal_def.GetName(sig_num)
|
| 218 | if name is None:
|
| 219 | return None
|
| 220 | return name[3:] # Remove SIG
|
| 221 |
|
| 222 | user_str = user_str.upper() # Ignore case
|
| 223 |
|
| 224 | if user_str in _HOOK_NAMES:
|
| 225 | return user_str
|
| 226 |
|
| 227 | if user_str.startswith('SIG'):
|
| 228 | user_str = user_str[3:]
|
| 229 |
|
| 230 | n = signal_def.GetNumber(user_str)
|
| 231 | if n == signal_def.NO_SIGNAL:
|
| 232 | return None
|
| 233 |
|
| 234 | return user_str
|
| 235 |
|
| 236 |
|
| 237 | def ParseSignalOrHook(user_str, blame_loc, allow_legacy=True):
|
| 238 | # type: (str, loc_t, bool) -> str
|
| 239 | """Convenience wrapper"""
|
| 240 | parsed_id = _ParseSignalOrHook(user_str,
|
| 241 | blame_loc,
|
| 242 | allow_legacy=allow_legacy)
|
| 243 | if parsed_id is None:
|
| 244 | raise error.Usage('expected signal or hook, got %r' % user_str,
|
| 245 | blame_loc)
|
| 246 | return parsed_id
|
| 247 |
|
| 248 |
|
| 249 | class Trap(vm._Builtin):
|
| 250 |
|
| 251 | def __init__(self, trap_state, parse_ctx, exec_opts, tracer, errfmt):
|
| 252 | # type: (TrapState, ParseContext, optview.Exec, dev.Tracer, ui.ErrorFormatter) -> None
|
| 253 | self.trap_state = trap_state
|
| 254 | self.parse_ctx = parse_ctx
|
| 255 | self.arena = parse_ctx.arena
|
| 256 | self.exec_opts = exec_opts
|
| 257 | self.tracer = tracer
|
| 258 | self.errfmt = errfmt
|
| 259 |
|
| 260 | def _ParseTrapCode(self, code_str):
|
| 261 | # type: (str) -> command_t
|
| 262 | """
|
| 263 | Returns:
|
| 264 | A node, or None if the code is invalid.
|
| 265 | """
|
| 266 | line_reader = reader.StringLineReader(code_str, self.arena)
|
| 267 | c_parser = self.parse_ctx.MakeOshParser(line_reader)
|
| 268 |
|
| 269 | # TODO: the SPID should be passed through argv.
|
| 270 | src = source.Dynamic('trap arg', loc.Missing)
|
| 271 | with alloc.ctx_SourceCode(self.arena, src):
|
| 272 | try:
|
| 273 | node = main_loop.ParseWholeFile(c_parser)
|
| 274 | except error.Parse as e:
|
| 275 | self.errfmt.PrettyPrintError(e)
|
| 276 | return None
|
| 277 |
|
| 278 | return node
|
| 279 |
|
| 280 | def _GetCommandSourceCode(self, body):
|
| 281 | # type: (command_t) -> str
|
| 282 |
|
| 283 | # TODO: Print ANY command_t variant
|
| 284 | handler_string = '<unknown>' # type: str
|
| 285 |
|
| 286 | if body.tag() == command_e.Simple:
|
| 287 | simple_cmd = cast(command.Simple, body)
|
| 288 | if simple_cmd.blame_tok:
|
| 289 | handler_string = simple_cmd.blame_tok.line.content
|
| 290 | return handler_string
|
| 291 |
|
| 292 | def _PrintTrapEntry(self, handler, name):
|
| 293 | # type: (command_t, str) -> None
|
| 294 | if handler.tag() == command_e.NoOp:
|
| 295 | print("trap -- '' %s" % name)
|
| 296 | else:
|
| 297 | code = self._GetCommandSourceCode(handler)
|
| 298 | print("trap -- %s %s" % (j8_lite.ShellEncode(code), name))
|
| 299 |
|
| 300 | def _PrintState(self):
|
| 301 | # type: () -> None
|
| 302 | for name, handler in iteritems(self.trap_state.hooks):
|
| 303 | self._PrintTrapEntry(handler, name)
|
| 304 |
|
| 305 | # Print in order of signal number
|
| 306 | n = signal_def.MaxSigNumber() + 1
|
| 307 | for sig_num in xrange(n):
|
| 308 | handler = self.trap_state.GetTrap(sig_num)
|
| 309 | if handler is None:
|
| 310 | continue
|
| 311 |
|
| 312 | sig_name = signal_def.GetName(sig_num)
|
| 313 | assert sig_name is not None
|
| 314 |
|
| 315 | self._PrintTrapEntry(handler, sig_name)
|
| 316 |
|
| 317 | def _PrintNames(self):
|
| 318 | # type: () -> None
|
| 319 | for hook_name in _HOOK_NAMES:
|
| 320 | # EXIT is 0, but we hide that
|
| 321 | print(' %s' % hook_name)
|
| 322 |
|
| 323 | process_osh.PrintSignals()
|
| 324 |
|
| 325 | def _AddTheRest(self, arg_r, node, allow_legacy=True):
|
| 326 | # type: (args.Reader, command_t, bool) -> int
|
| 327 | """Add a handler for all args"""
|
| 328 | while not arg_r.AtEnd():
|
| 329 | arg_str, arg_loc = arg_r.Peek2()
|
| 330 | parsed_id = ParseSignalOrHook(arg_str,
|
| 331 | arg_loc,
|
| 332 | allow_legacy=allow_legacy)
|
| 333 |
|
| 334 | if parsed_id == 'RETURN':
|
| 335 | print_stderr("osh warning: The %r hook isn't implemented" %
|
| 336 | arg_str)
|
| 337 | if parsed_id == 'STOP' or parsed_id == 'KILL':
|
| 338 | self.errfmt.Print_("Signal %r can't be handled" % arg_str,
|
| 339 | blame_loc=arg_loc)
|
| 340 | # Other shells return 0, but this seems like an obvious error
|
| 341 | return 2
|
| 342 |
|
| 343 | self.trap_state.AddItem(parsed_id, node)
|
| 344 |
|
| 345 | arg_r.Next()
|
| 346 | return 0
|
| 347 |
|
| 348 | def _RemoveTheRest(self, arg_r, allow_legacy=True):
|
| 349 | # type: (args.Reader, bool) -> None
|
| 350 | """Remove handlers for all args"""
|
| 351 | while not arg_r.AtEnd():
|
| 352 | arg_str, arg_loc = arg_r.Peek2()
|
| 353 | parsed_id = ParseSignalOrHook(arg_str,
|
| 354 | arg_loc,
|
| 355 | allow_legacy=allow_legacy)
|
| 356 | self.trap_state.RemoveItem(parsed_id)
|
| 357 | arg_r.Next()
|
| 358 |
|
| 359 | def Run(self, cmd_val):
|
| 360 | # type: (cmd_value.Argv) -> int
|
| 361 | attrs, arg_r = flag_util.ParseCmdVal('trap',
|
| 362 | cmd_val,
|
| 363 | accept_typed_args=True)
|
| 364 | arg = arg_types.trap(attrs.attrs)
|
| 365 |
|
| 366 | if arg.add: # trap --add
|
| 367 | cmd_frag = typed_args.RequiredBlockAsFrag(cmd_val)
|
| 368 | return self._AddTheRest(arg_r, cmd_frag, allow_legacy=False)
|
| 369 |
|
| 370 | if arg.ignore: # trap --ignore
|
| 371 | return self._AddTheRest(arg_r, command.NoOp, allow_legacy=False)
|
| 372 |
|
| 373 | if arg.remove: # trap --remove
|
| 374 | self._RemoveTheRest(arg_r, allow_legacy=False)
|
| 375 | return 0
|
| 376 |
|
| 377 | if arg.p: # trap -p prints handlers
|
| 378 | self._PrintState()
|
| 379 | return 0
|
| 380 |
|
| 381 | if arg.l: # List valid signals and hooks
|
| 382 | self._PrintNames()
|
| 383 | return 0
|
| 384 |
|
| 385 | # Anything other than the above is not supported in YSH pass
|
| 386 | if self.exec_opts.simple_trap_builtin():
|
| 387 | raise error.Usage(
|
| 388 | 'expected --add, --remove, -l, or -p (simple_trap_builtin)',
|
| 389 | cmd_val.arg_locs[0])
|
| 390 |
|
| 391 | # 'trap' with no arguments is equivalent to 'trap -p'
|
| 392 | if arg_r.AtEnd():
|
| 393 | self._PrintState()
|
| 394 | return 0
|
| 395 |
|
| 396 | first_arg, first_loc = arg_r.Peek2()
|
| 397 |
|
| 398 | # If the first arg is '-' or an unsigned integer, then remove the
|
| 399 | # handlers. For example, 'trap 0 2' or 'trap 0 SIGINT'
|
| 400 | #
|
| 401 | # https://pubs.opengroup.org/onlinepubs/9699919799.2018edition/utilities/V3_chap02.html#tag_18_28
|
| 402 | first_is_dash = (first_arg == '-')
|
| 403 | if first_is_dash or first_arg.isdigit():
|
| 404 | if first_is_dash:
|
| 405 | arg_r.Next()
|
| 406 |
|
| 407 | self._RemoveTheRest(arg_r)
|
| 408 | return 0
|
| 409 |
|
| 410 | arg_r.Next()
|
| 411 |
|
| 412 | # If first arg is empty string '', ignore the specified signals
|
| 413 | if len(first_arg) == 0:
|
| 414 | return self._AddTheRest(arg_r, command.NoOp)
|
| 415 |
|
| 416 | # Legacy behavior for only one arg: 'trap SIGNAL' removes the handler
|
| 417 | if arg_r.AtEnd():
|
| 418 | parsed_id = ParseSignalOrHook(first_arg, first_loc)
|
| 419 | self.trap_state.RemoveItem(parsed_id)
|
| 420 | return 0
|
| 421 |
|
| 422 | # Unlike other shells, we parse the code upon registration
|
| 423 | node = self._ParseTrapCode(first_arg)
|
| 424 | if node is None:
|
| 425 | return 1 # _ParseTrapCode() prints an error for us.
|
| 426 |
|
| 427 | # trap COMMAND SIGNAL+
|
| 428 | return self._AddTheRest(arg_r, node)
|