| 1 | #!/usr/bin/env python2
|
| 2 | """Builtin_trap.py."""
|
| 3 | from __future__ import print_function
|
| 4 |
|
| 5 | from signal import SIG_DFL, SIGINT, SIGKILL, SIGSTOP, SIGWINCH
|
| 6 |
|
| 7 | from _devbuild.gen import arg_types
|
| 8 | from _devbuild.gen.runtime_asdl import cmd_value
|
| 9 | from _devbuild.gen.syntax_asdl import loc, source
|
| 10 | from core import alloc
|
| 11 | from core import dev
|
| 12 | from core import error
|
| 13 | from core import main_loop
|
| 14 | from mycpp.mylib import log
|
| 15 | from core import pyos
|
| 16 | from core import vm
|
| 17 | from frontend import flag_util
|
| 18 | from frontend import signal_def
|
| 19 | from frontend import reader
|
| 20 | from mycpp import mylib
|
| 21 | from mycpp.mylib import iteritems, print_stderr
|
| 22 |
|
| 23 | from typing import Dict, List, Optional, TYPE_CHECKING
|
| 24 | if TYPE_CHECKING:
|
| 25 | from _devbuild.gen.syntax_asdl import command_t
|
| 26 | from core.ui import ErrorFormatter
|
| 27 | from frontend.parse_lib import ParseContext
|
| 28 |
|
| 29 | _ = log
|
| 30 |
|
| 31 |
|
| 32 | class TrapState(object):
|
| 33 | """Traps are shell callbacks that the user wants to run on certain events.
|
| 34 |
|
| 35 | There are 2 catogires:
|
| 36 | 1. Signals like SIGUSR1
|
| 37 | 2. Hooks like EXIT
|
| 38 |
|
| 39 | Signal handlers execute in the main loop, and within blocking syscalls.
|
| 40 |
|
| 41 | EXIT, DEBUG, ERR, RETURN execute in specific places in the interpreter.
|
| 42 | """
|
| 43 |
|
| 44 | def __init__(self, signal_safe):
|
| 45 | # type: (pyos.SignalSafe) -> None
|
| 46 | self.signal_safe = signal_safe
|
| 47 | self.hooks = {} # type: Dict[str, command_t]
|
| 48 | self.traps = {} # type: Dict[int, command_t]
|
| 49 |
|
| 50 | def ClearForSubProgram(self):
|
| 51 | # type: () -> None
|
| 52 | """SubProgramThunk uses this because traps aren't inherited."""
|
| 53 |
|
| 54 | # bash clears DEBUG hook in subshell, command sub, etc. See
|
| 55 | # spec/builtin-trap-bash.
|
| 56 | self.hooks.clear()
|
| 57 | self.traps.clear()
|
| 58 |
|
| 59 | def GetHook(self, hook_name):
|
| 60 | # type: (str) -> command_t
|
| 61 | """ e.g. EXIT hook. """
|
| 62 | return self.hooks.get(hook_name, None)
|
| 63 |
|
| 64 | def AddUserHook(self, hook_name, handler):
|
| 65 | # type: (str, command_t) -> None
|
| 66 | self.hooks[hook_name] = handler
|
| 67 |
|
| 68 | def RemoveUserHook(self, hook_name):
|
| 69 | # type: (str) -> None
|
| 70 | mylib.dict_erase(self.hooks, hook_name)
|
| 71 |
|
| 72 | def AddUserTrap(self, sig_num, handler):
|
| 73 | # type: (int, command_t) -> None
|
| 74 | """E.g.
|
| 75 |
|
| 76 | SIGUSR1.
|
| 77 | """
|
| 78 | self.traps[sig_num] = handler
|
| 79 |
|
| 80 | if sig_num == SIGWINCH:
|
| 81 | self.signal_safe.SetSigWinchCode(SIGWINCH)
|
| 82 | else:
|
| 83 | pyos.RegisterSignalInterest(sig_num)
|
| 84 |
|
| 85 | def RemoveUserTrap(self, sig_num):
|
| 86 | # type: (int) -> None
|
| 87 |
|
| 88 | mylib.dict_erase(self.traps, sig_num)
|
| 89 |
|
| 90 | if sig_num == SIGINT:
|
| 91 | # Don't disturb the runtime signal handlers:
|
| 92 | # 1. from CPython
|
| 93 | # 2. pyos::InitSignalSafe() calls RegisterSignalInterest(SIGINT)
|
| 94 | pass
|
| 95 | elif sig_num == SIGWINCH:
|
| 96 | self.signal_safe.SetSigWinchCode(pyos.UNTRAPPED_SIGWINCH)
|
| 97 | else:
|
| 98 | pyos.Sigaction(sig_num, SIG_DFL)
|
| 99 |
|
| 100 | def GetPendingTraps(self):
|
| 101 | # type: () -> Optional[List[command_t]]
|
| 102 | """Transfer ownership of the current queue of pending trap handlers to
|
| 103 | the caller."""
|
| 104 | signals = self.signal_safe.TakePendingSignals()
|
| 105 |
|
| 106 | # Optimization for the common case: do not allocate a list. This function
|
| 107 | # is called in the interpreter loop.
|
| 108 | if len(signals) == 0:
|
| 109 | self.signal_safe.ReuseEmptyList(signals)
|
| 110 | return None
|
| 111 |
|
| 112 | run_list = [] # type: List[command_t]
|
| 113 | for sig_num in signals:
|
| 114 | node = self.traps.get(sig_num, None)
|
| 115 | if node is not None:
|
| 116 | run_list.append(node)
|
| 117 |
|
| 118 | # Optimization to avoid allocation in the main loop.
|
| 119 | del signals[:]
|
| 120 | self.signal_safe.ReuseEmptyList(signals)
|
| 121 |
|
| 122 | return run_list
|
| 123 |
|
| 124 |
|
| 125 | def _GetSignalNumber(sig_spec):
|
| 126 | # type: (str) -> int
|
| 127 |
|
| 128 | # POSIX lists the numbers that are required.
|
| 129 | # http://pubs.opengroup.org/onlinepubs/9699919799/
|
| 130 | #
|
| 131 | # Added 13 for SIGPIPE because autoconf's 'configure' uses it!
|
| 132 | if sig_spec.strip() in ('1', '2', '3', '6', '9', '13', '14', '15'):
|
| 133 | return int(sig_spec)
|
| 134 |
|
| 135 | # INT is an alias for SIGINT
|
| 136 | if sig_spec.startswith('SIG'):
|
| 137 | sig_spec = sig_spec[3:]
|
| 138 | return signal_def.GetNumber(sig_spec)
|
| 139 |
|
| 140 |
|
| 141 | _HOOK_NAMES = ['EXIT', 'ERR', 'RETURN', 'DEBUG']
|
| 142 |
|
| 143 | # bash's default -p looks like this:
|
| 144 | # trap -- '' SIGTSTP
|
| 145 | # trap -- '' SIGTTIN
|
| 146 | # trap -- '' SIGTTOU
|
| 147 | #
|
| 148 | # CPython registers different default handlers. The C++ rewrite should make
|
| 149 | # OVM match sh/bash more closely.
|
| 150 |
|
| 151 | # Example of trap:
|
| 152 | # trap -- 'echo "hi there" | wc ' SIGINT
|
| 153 | #
|
| 154 | # Then hit Ctrl-C.
|
| 155 |
|
| 156 |
|
| 157 | class Trap(vm._Builtin):
|
| 158 |
|
| 159 | def __init__(self, trap_state, parse_ctx, tracer, errfmt):
|
| 160 | # type: (TrapState, ParseContext, dev.Tracer, ErrorFormatter) -> None
|
| 161 | self.trap_state = trap_state
|
| 162 | self.parse_ctx = parse_ctx
|
| 163 | self.arena = parse_ctx.arena
|
| 164 | self.tracer = tracer
|
| 165 | self.errfmt = errfmt
|
| 166 |
|
| 167 | def _ParseTrapCode(self, code_str):
|
| 168 | # type: (str) -> command_t
|
| 169 | """
|
| 170 | Returns:
|
| 171 | A node, or None if the code is invalid.
|
| 172 | """
|
| 173 | line_reader = reader.StringLineReader(code_str, self.arena)
|
| 174 | c_parser = self.parse_ctx.MakeOshParser(line_reader)
|
| 175 |
|
| 176 | # TODO: the SPID should be passed through argv.
|
| 177 | src = source.ArgvWord('trap', loc.Missing)
|
| 178 | with alloc.ctx_SourceCode(self.arena, src):
|
| 179 | try:
|
| 180 | node = main_loop.ParseWholeFile(c_parser)
|
| 181 | except error.Parse as e:
|
| 182 | self.errfmt.PrettyPrintError(e)
|
| 183 | return None
|
| 184 |
|
| 185 | return node
|
| 186 |
|
| 187 | def Run(self, cmd_val):
|
| 188 | # type: (cmd_value.Argv) -> int
|
| 189 | attrs, arg_r = flag_util.ParseCmdVal('trap', cmd_val)
|
| 190 | arg = arg_types.trap(attrs.attrs)
|
| 191 |
|
| 192 | if arg.p: # Print registered handlers
|
| 193 | # The unit tests rely on this being one line.
|
| 194 | # bash prints a line that can be re-parsed.
|
| 195 | for name, _ in iteritems(self.trap_state.hooks):
|
| 196 | print('%s TrapState' % (name, ))
|
| 197 |
|
| 198 | for sig_num, _ in iteritems(self.trap_state.traps):
|
| 199 | print('%d TrapState' % (sig_num, ))
|
| 200 |
|
| 201 | return 0
|
| 202 |
|
| 203 | if arg.l: # List valid signals and hooks
|
| 204 | for hook_name in _HOOK_NAMES:
|
| 205 | print(' %s' % hook_name)
|
| 206 |
|
| 207 | signal_def.PrintSignals()
|
| 208 |
|
| 209 | return 0
|
| 210 |
|
| 211 | code_str = arg_r.ReadRequired('requires a code string')
|
| 212 | sig_spec, sig_loc = arg_r.ReadRequired2(
|
| 213 | 'requires a signal or hook name')
|
| 214 |
|
| 215 | # sig_key is NORMALIZED sig_spec: a signal number string or string hook
|
| 216 | # name.
|
| 217 | sig_key = None # type: Optional[str]
|
| 218 | sig_num = signal_def.NO_SIGNAL
|
| 219 |
|
| 220 | if sig_spec in _HOOK_NAMES:
|
| 221 | sig_key = sig_spec
|
| 222 | elif sig_spec == '0': # Special case
|
| 223 | sig_key = 'EXIT'
|
| 224 | else:
|
| 225 | sig_num = _GetSignalNumber(sig_spec)
|
| 226 | if sig_num != signal_def.NO_SIGNAL:
|
| 227 | sig_key = str(sig_num)
|
| 228 |
|
| 229 | if sig_key is None:
|
| 230 | self.errfmt.Print_("Invalid signal or hook %r" % sig_spec,
|
| 231 | blame_loc=cmd_val.arg_locs[2])
|
| 232 | return 1
|
| 233 |
|
| 234 | # NOTE: sig_spec isn't validated when removing handlers.
|
| 235 | if code_str == '-':
|
| 236 | if sig_key in _HOOK_NAMES:
|
| 237 | self.trap_state.RemoveUserHook(sig_key)
|
| 238 | return 0
|
| 239 |
|
| 240 | if sig_num != signal_def.NO_SIGNAL:
|
| 241 | self.trap_state.RemoveUserTrap(sig_num)
|
| 242 | return 0
|
| 243 |
|
| 244 | raise AssertionError('Signal or trap')
|
| 245 |
|
| 246 | # Try parsing the code first.
|
| 247 |
|
| 248 | # TODO: If simple_trap is on (for oil:upgrade), then it must be a function
|
| 249 | # name? And then you wrap it in 'try'?
|
| 250 |
|
| 251 | node = self._ParseTrapCode(code_str)
|
| 252 | if node is None:
|
| 253 | return 1 # ParseTrapCode() prints an error for us.
|
| 254 |
|
| 255 | # Register a hook.
|
| 256 | if sig_key in _HOOK_NAMES:
|
| 257 | if sig_key == 'RETURN':
|
| 258 | print_stderr("osh warning: The %r hook isn't implemented" %
|
| 259 | sig_spec)
|
| 260 | self.trap_state.AddUserHook(sig_key, node)
|
| 261 | return 0
|
| 262 |
|
| 263 | # Register a signal.
|
| 264 | if sig_num != signal_def.NO_SIGNAL:
|
| 265 | # For signal handlers, the traps dictionary is used only for debugging.
|
| 266 | if sig_num in (SIGKILL, SIGSTOP):
|
| 267 | self.errfmt.Print_("Signal %r can't be handled" % sig_spec,
|
| 268 | blame_loc=sig_loc)
|
| 269 | # Other shells return 0, but this seems like an obvious error
|
| 270 | return 1
|
| 271 | self.trap_state.AddUserTrap(sig_num, node)
|
| 272 | return 0
|
| 273 |
|
| 274 | raise AssertionError('Signal or trap')
|