| 1 | #!/usr/bin/env python2
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| 2 | from __future__ import print_function
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| 3 |
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| 4 | from signal import SIG_DFL, SIG_IGN, SIGINT, SIGWINCH
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| 5 |
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| 6 | from _devbuild.gen import arg_types
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| 7 | from _devbuild.gen.runtime_asdl import cmd_value
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| 8 | from _devbuild.gen.syntax_asdl import loc, loc_t, source, command_e, command
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| 9 | from core import alloc
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| 10 | from core import dev
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| 11 | from core import error
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| 12 | from core import main_loop
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| 13 | from core import vm
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| 14 | from frontend import flag_util
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| 15 | from frontend import reader
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| 16 | from frontend import signal_def
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| 17 | from frontend import typed_args
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| 18 | from builtin import process_osh # for PrintSignals()
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| 19 | from data_lang import j8_lite
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| 20 | from mycpp import iolib
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| 21 | from mycpp import mylib
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| 22 | from mycpp.mylib import iteritems, print_stderr, log
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| 23 |
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| 24 | from typing import Dict, List, Optional, TYPE_CHECKING, cast
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| 25 | if TYPE_CHECKING:
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| 26 | from _devbuild.gen.syntax_asdl import command_t
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| 27 | from core import optview
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| 28 | from display import ui
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| 29 | from frontend import args
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| 30 | from frontend.parse_lib import ParseContext
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| 31 |
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| 32 | _ = log
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| 33 |
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| 34 |
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| 35 | class TrapState(object):
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| 36 | """Traps are shell callbacks that the user wants to run on certain events.
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| 37 |
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| 38 | There are 2 catogires:
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| 39 | 1. Signals like SIGUSR1
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| 40 | 2. Hooks like EXIT
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| 41 |
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| 42 | Signal handlers execute in the main loop, and within blocking syscalls.
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| 43 |
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| 44 | EXIT, DEBUG, ERR, RETURN execute in specific places in the interpreter.
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| 45 | """
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| 46 |
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| 47 | def __init__(self, signal_safe):
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| 48 | # type: (iolib.SignalSafe) -> None
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| 49 | self.signal_safe = signal_safe
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| 50 | self.hooks = {} # type: Dict[str, command_t]
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| 51 | self.traps = {} # type: Dict[int, command_t]
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| 52 |
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| 53 | def ClearForSubProgram(self, inherit_errtrace):
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| 54 | # type: (bool) -> None
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| 55 | """SubProgramThunk uses this because traps aren't inherited."""
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| 56 |
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| 57 | # bash clears hooks like DEBUG in subshells.
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| 58 | # The ERR can be preserved if set -o errtrace
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| 59 | hook_err = self.hooks.get('ERR')
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| 60 | self.hooks.clear()
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| 61 | if hook_err is not None and inherit_errtrace:
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| 62 | self.hooks['ERR'] = hook_err
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| 63 |
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| 64 | self.traps.clear()
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| 65 |
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| 66 | def GetHook(self, hook_name):
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| 67 | # type: (str) -> command_t
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| 68 | """ e.g. EXIT hook. """
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| 69 | return self.hooks.get(hook_name, None)
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| 70 |
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| 71 | def GetTrap(self, sig_num):
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| 72 | # type: (int) -> command_t
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| 73 | return self.traps.get(sig_num, None)
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| 74 |
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| 75 | def _AddUserTrap(self, sig_num, handler):
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| 76 | # type: (int, command_t) -> None
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| 77 | """ e.g. SIGUSR1 """
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| 78 | self.traps[sig_num] = handler
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| 79 |
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| 80 | if handler.tag() == command_e.NoOp:
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| 81 | # This is the case:
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| 82 | # trap '' SIGINT SIGWINCH
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| 83 | # It's handled the same as removing a trap:
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| 84 | # trap - SIGINT SIGWINCH
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| 85 | #
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| 86 | # That is, the signal_safe calls are the same. This seems right
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| 87 | # because the shell interpreter itself cares about SIGINT and
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| 88 | # SIGWINCH too -- not just user traps.
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| 89 | if sig_num == SIGINT:
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| 90 | self.signal_safe.SetSigIntTrapped(False)
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| 91 | elif sig_num == SIGWINCH:
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| 92 | self.signal_safe.SetSigWinchCode(iolib.UNTRAPPED_SIGWINCH)
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| 93 | else:
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| 94 | iolib.sigaction(sig_num, SIG_IGN)
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| 95 | else:
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| 96 | if sig_num == SIGINT:
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| 97 | # Don't disturb the underlying runtime's SIGINT handllers
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| 98 | # 1. CPython has one for KeyboardInterrupt
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| 99 | # 2. mycpp runtime simulates KeyboardInterrupt:
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| 100 | # pyos::InitSignalSafe() calls RegisterSignalInterest(SIGINT),
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| 101 | # then we PollSigInt() in the osh/cmd_eval.py main loop
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| 102 | self.signal_safe.SetSigIntTrapped(True)
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| 103 | elif sig_num == SIGWINCH:
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| 104 | self.signal_safe.SetSigWinchCode(SIGWINCH)
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| 105 | else:
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| 106 | iolib.RegisterSignalInterest(sig_num)
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| 107 |
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| 108 | def _RemoveUserTrap(self, sig_num):
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| 109 | # type: (int) -> None
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| 110 |
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| 111 | mylib.dict_erase(self.traps, sig_num)
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| 112 |
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| 113 | if sig_num == SIGINT:
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| 114 | self.signal_safe.SetSigIntTrapped(False)
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| 115 | elif sig_num == SIGWINCH:
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| 116 | self.signal_safe.SetSigWinchCode(iolib.UNTRAPPED_SIGWINCH)
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| 117 | else:
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| 118 | # TODO: In process.InitInteractiveShell(), 4 signals are set to
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| 119 | # SIG_IGN, not SIG_DFL:
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| 120 | #
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| 121 | # SIGQUIT SIGTSTP SIGTTOU SIGTTIN
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| 122 | #
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| 123 | # Should we restore them? It's rare that you type 'trap' in
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| 124 | # interactive shells, but it might be more correct. See what other
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| 125 | # shells do.
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| 126 | iolib.sigaction(sig_num, SIG_DFL)
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| 127 |
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| 128 | def AddItem(self, parsed_id, handler):
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| 129 | # type: (str, command_t) -> None
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| 130 | """Add trap or hook, parsed to EXIT or INT (not 0 or SIGINT)"""
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| 131 | if parsed_id in _HOOK_NAMES:
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| 132 | self.hooks[parsed_id] = handler
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| 133 | else:
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| 134 | sig_num = signal_def.GetNumber(parsed_id)
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| 135 | # Should have already been validated
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| 136 | assert sig_num is not signal_def.NO_SIGNAL
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| 137 |
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| 138 | self._AddUserTrap(sig_num, handler)
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| 139 |
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| 140 | def RemoveItem(self, parsed_id):
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| 141 | # type: (str) -> None
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| 142 | """Remove trap or hook, parsed to EXIT or INT (not 0 or SIGINT)"""
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| 143 | if parsed_id in _HOOK_NAMES:
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| 144 | mylib.dict_erase(self.hooks, parsed_id)
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| 145 | else:
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| 146 | sig_num = signal_def.GetNumber(parsed_id)
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| 147 | # Should have already been validated
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| 148 | assert sig_num is not signal_def.NO_SIGNAL
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| 149 |
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| 150 | self._RemoveUserTrap(sig_num)
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| 151 |
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| 152 | def GetPendingTraps(self):
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| 153 | # type: () -> Optional[List[command_t]]
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| 154 | """Transfer ownership of queue of pending trap handlers to caller."""
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| 155 | signals = self.signal_safe.TakePendingSignals()
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| 156 | if 0:
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| 157 | log('*** GetPendingTraps')
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| 158 | for si in signals:
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| 159 | log('SIGNAL %d', si)
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| 160 | #import traceback
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| 161 | #traceback.print_stack()
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| 162 |
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| 163 | # Optimization for the common case: do not allocate a list. This function
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| 164 | # is called in the interpreter loop.
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| 165 | if len(signals) == 0:
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| 166 | self.signal_safe.ReuseEmptyList(signals)
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| 167 | return None
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| 168 |
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| 169 | run_list = [] # type: List[command_t]
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| 170 | for sig_num in signals:
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| 171 | node = self.traps.get(sig_num, None)
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| 172 | if node is not None:
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| 173 | run_list.append(node)
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| 174 |
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| 175 | # Optimization to avoid allocation in the main loop.
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| 176 | del signals[:]
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| 177 | self.signal_safe.ReuseEmptyList(signals)
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| 178 |
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| 179 | return run_list
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| 180 |
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| 181 | def ThisProcessHasTraps(self):
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| 182 | # type: () -> bool
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| 183 | """
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| 184 | noforklast optimizations are not enabled when the process has code to
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| 185 | run after fork!
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| 186 | """
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| 187 | if 0:
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| 188 | log('traps %d', len(self.traps))
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| 189 | log('hooks %d', len(self.hooks))
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| 190 | return len(self.traps) != 0 or len(self.hooks) != 0
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| 191 |
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| 192 |
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| 193 | _HOOK_NAMES = ['EXIT', 'ERR', 'RETURN', 'DEBUG']
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| 194 |
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| 195 |
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| 196 | def _ParseSignalOrHook(user_str, blame_loc, allow_legacy=True):
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| 197 | # type: (str, loc_t, bool) -> str
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| 198 | """Convert user string to a parsed/normalized string.
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| 199 |
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| 200 | These can be passed to AddItem() and RemoveItem()
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| 201 |
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| 202 | See unit tests in builtin/trap_osh_test.py
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| 203 | '0' -> 'EXIT'
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| 204 | 'EXIT' -> 'EXIT'
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| 205 | 'eXIT' -> 'EXIT'
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| 206 |
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| 207 | '2' -> 'INT'
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| 208 | 'iNT' -> 'INT'
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| 209 | 'sIGINT' -> 'INT'
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| 210 |
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| 211 | 'zz' -> error
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| 212 | '-150' -> error
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| 213 | '10000' -> error
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| 214 | """
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| 215 | if allow_legacy and user_str.isdigit():
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| 216 | try:
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| 217 | sig_num = int(user_str)
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| 218 | except ValueError:
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| 219 | raise error.Usage("got overflowing integer: %s" % user_str,
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| 220 | blame_loc)
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| 221 |
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| 222 | if sig_num == 0: # Special case
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| 223 | return 'EXIT'
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| 224 |
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| 225 | name = signal_def.GetName(sig_num)
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| 226 | if name is None:
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| 227 | return None
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| 228 | return name[3:] # Remove SIG
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| 229 |
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| 230 | user_str = user_str.upper() # Ignore case
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| 231 |
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| 232 | if user_str in _HOOK_NAMES:
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| 233 | return user_str
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| 234 |
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| 235 | if user_str.startswith('SIG'):
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| 236 | user_str = user_str[3:]
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| 237 |
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| 238 | n = signal_def.GetNumber(user_str)
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| 239 | if n == signal_def.NO_SIGNAL:
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| 240 | return None
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| 241 |
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| 242 | return user_str
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| 243 |
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| 244 |
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| 245 | def ParseSignalOrHook(user_str, blame_loc, allow_legacy=True):
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| 246 | # type: (str, loc_t, bool) -> str
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| 247 | """Convenience wrapper"""
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| 248 | parsed_id = _ParseSignalOrHook(user_str,
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| 249 | blame_loc,
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| 250 | allow_legacy=allow_legacy)
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| 251 | if parsed_id is None:
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| 252 | raise error.Usage('expected signal or hook, got %r' % user_str,
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| 253 | blame_loc)
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| 254 | return parsed_id
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| 255 |
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| 256 |
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| 257 | class Trap(vm._Builtin):
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| 258 |
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| 259 | def __init__(self, trap_state, parse_ctx, exec_opts, tracer, errfmt):
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| 260 | # type: (TrapState, ParseContext, optview.Exec, dev.Tracer, ui.ErrorFormatter) -> None
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| 261 | self.trap_state = trap_state
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| 262 | self.parse_ctx = parse_ctx
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| 263 | self.arena = parse_ctx.arena
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| 264 | self.exec_opts = exec_opts
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| 265 | self.tracer = tracer
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| 266 | self.errfmt = errfmt
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| 267 |
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| 268 | def _ParseTrapCode(self, code_str):
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| 269 | # type: (str) -> command_t
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| 270 | """
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| 271 | Returns:
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| 272 | A node, or None if the code is invalid.
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| 273 | """
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| 274 | line_reader = reader.StringLineReader(code_str, self.arena)
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| 275 | c_parser = self.parse_ctx.MakeOshParser(line_reader)
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| 276 |
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| 277 | # TODO: the SPID should be passed through argv.
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| 278 | src = source.Dynamic('trap arg', loc.Missing)
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| 279 | with alloc.ctx_SourceCode(self.arena, src):
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| 280 | try:
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| 281 | node = main_loop.ParseWholeFile(c_parser)
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| 282 | except error.Parse as e:
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| 283 | self.errfmt.PrettyPrintError(e)
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| 284 | return None
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| 285 |
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| 286 | return node
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| 287 |
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| 288 | def _GetCommandSourceCode(self, body):
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| 289 | # type: (command_t) -> str
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| 290 |
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| 291 | # TODO: Print ANY command_t variant
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| 292 | handler_string = '<unknown>' # type: str
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| 293 |
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| 294 | if body.tag() == command_e.Simple:
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| 295 | simple_cmd = cast(command.Simple, body)
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| 296 | if simple_cmd.blame_tok:
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| 297 | handler_string = simple_cmd.blame_tok.line.content
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| 298 | return handler_string
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| 299 |
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| 300 | def _PrintTrapEntry(self, handler, name):
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| 301 | # type: (command_t, str) -> None
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| 302 | if handler.tag() == command_e.NoOp:
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| 303 | print("trap -- '' %s" % name)
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| 304 | else:
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| 305 | code = self._GetCommandSourceCode(handler)
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| 306 | print("trap -- %s %s" % (j8_lite.ShellEncode(code), name))
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| 307 |
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| 308 | def _PrintState(self):
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| 309 | # type: () -> None
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| 310 | for name, handler in iteritems(self.trap_state.hooks):
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| 311 | self._PrintTrapEntry(handler, name)
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| 312 |
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| 313 | # Print in order of signal number
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| 314 | n = signal_def.MaxSigNumber() + 1
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| 315 | for sig_num in xrange(n):
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| 316 | handler = self.trap_state.GetTrap(sig_num)
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| 317 | if handler is None:
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| 318 | continue
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| 319 |
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| 320 | sig_name = signal_def.GetName(sig_num)
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| 321 | assert sig_name is not None
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| 322 |
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| 323 | self._PrintTrapEntry(handler, sig_name)
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| 324 |
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| 325 | def _PrintNames(self):
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| 326 | # type: () -> None
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| 327 | for hook_name in _HOOK_NAMES:
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| 328 | # EXIT is 0, but we hide that
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| 329 | print(' %s' % hook_name)
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| 330 |
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| 331 | process_osh.PrintSignals()
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| 332 |
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| 333 | def _AddTheRest(self, arg_r, node, allow_legacy=True):
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| 334 | # type: (args.Reader, command_t, bool) -> int
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| 335 | """Add a handler for all args"""
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| 336 | while not arg_r.AtEnd():
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| 337 | arg_str, arg_loc = arg_r.Peek2()
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| 338 | parsed_id = ParseSignalOrHook(arg_str,
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| 339 | arg_loc,
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| 340 | allow_legacy=allow_legacy)
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| 341 |
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| 342 | if parsed_id == 'RETURN':
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| 343 | print_stderr("osh warning: The %r hook isn't implemented" %
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| 344 | arg_str)
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| 345 | if parsed_id == 'STOP' or parsed_id == 'KILL':
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| 346 | self.errfmt.Print_("Signal %r can't be handled" % arg_str,
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| 347 | blame_loc=arg_loc)
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| 348 | # Other shells return 0, but this seems like an obvious error
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| 349 | return 2
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| 350 |
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| 351 | self.trap_state.AddItem(parsed_id, node)
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| 352 |
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| 353 | arg_r.Next()
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| 354 | return 0
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| 355 |
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| 356 | def _RemoveTheRest(self, arg_r, allow_legacy=True):
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| 357 | # type: (args.Reader, bool) -> None
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| 358 | """Remove handlers for all args"""
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| 359 | while not arg_r.AtEnd():
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| 360 | arg_str, arg_loc = arg_r.Peek2()
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| 361 | parsed_id = ParseSignalOrHook(arg_str,
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| 362 | arg_loc,
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| 363 | allow_legacy=allow_legacy)
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| 364 | self.trap_state.RemoveItem(parsed_id)
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| 365 | arg_r.Next()
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| 366 |
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| 367 | def Run(self, cmd_val):
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| 368 | # type: (cmd_value.Argv) -> int
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| 369 | attrs, arg_r = flag_util.ParseCmdVal('trap',
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| 370 | cmd_val,
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| 371 | accept_typed_args=True)
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| 372 | arg = arg_types.trap(attrs.attrs)
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| 373 |
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| 374 | if arg.add: # trap --add
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| 375 | cmd_frag = typed_args.RequiredBlockAsFrag(cmd_val)
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| 376 | return self._AddTheRest(arg_r, cmd_frag, allow_legacy=False)
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| 377 |
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| 378 | if arg.ignore: # trap --ignore
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| 379 | return self._AddTheRest(arg_r, command.NoOp, allow_legacy=False)
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| 380 |
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| 381 | if arg.remove: # trap --remove
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| 382 | self._RemoveTheRest(arg_r, allow_legacy=False)
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| 383 | return 0
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| 384 |
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| 385 | if arg.p: # trap -p prints handlers
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| 386 | self._PrintState()
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| 387 | return 0
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| 388 |
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| 389 | if arg.l: # List valid signals and hooks
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| 390 | self._PrintNames()
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| 391 | return 0
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| 392 |
|
| 393 | # Anything other than the above is not supported in YSH pass
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| 394 | if self.exec_opts.simple_trap_builtin():
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| 395 | raise error.Usage(
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| 396 | 'expected --add, --remove, -l, or -p (simple_trap_builtin)',
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| 397 | cmd_val.arg_locs[0])
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| 398 |
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| 399 | # 'trap' with no arguments is equivalent to 'trap -p'
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| 400 | if arg_r.AtEnd():
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| 401 | self._PrintState()
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| 402 | return 0
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| 403 |
|
| 404 | first_arg, first_loc = arg_r.Peek2()
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| 405 |
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| 406 | # If the first arg is '-' or an unsigned integer, then remove the
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| 407 | # handlers. For example, 'trap 0 2' or 'trap 0 SIGINT'
|
| 408 | #
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| 409 | # https://pubs.opengroup.org/onlinepubs/9699919799.2018edition/utilities/V3_chap02.html#tag_18_28
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| 410 | first_is_dash = (first_arg == '-')
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| 411 | if first_is_dash or first_arg.isdigit():
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| 412 | if first_is_dash:
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| 413 | arg_r.Next()
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| 414 |
|
| 415 | self._RemoveTheRest(arg_r)
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| 416 | return 0
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| 417 |
|
| 418 | arg_r.Next()
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| 419 |
|
| 420 | # If first arg is empty string '', ignore the specified signals
|
| 421 | if len(first_arg) == 0:
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| 422 | return self._AddTheRest(arg_r, command.NoOp)
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| 423 |
|
| 424 | # Legacy behavior for only one arg: 'trap SIGNAL' removes the handler
|
| 425 | if arg_r.AtEnd():
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| 426 | parsed_id = ParseSignalOrHook(first_arg, first_loc)
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| 427 | self.trap_state.RemoveItem(parsed_id)
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| 428 | return 0
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| 429 |
|
| 430 | # Unlike other shells, we parse the code upon registration
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| 431 | node = self._ParseTrapCode(first_arg)
|
| 432 | if node is None:
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| 433 | return 1 # _ParseTrapCode() prints an error for us.
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| 434 |
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| 435 | # trap COMMAND SIGNAL+
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| 436 | return self._AddTheRest(arg_r, node)
|