trap.c

android-w.song.android.widget

sighandler
trap_handler (sig)
     int sig;
{
  int oerrno;

  if ((sigmodes[sig] & SIG_TRAPPED) == 0)
    {
#if defined (DEBUG)
      internal_warning ("trap_handler: signal %d: signal not trapped", sig);
#endif
      SIGRETURN (0);
    }

  if ((sig >= NSIG) ||
      (trap_list[sig] == (char *)DEFAULT_SIG) ||
      (trap_list[sig] == (char *)IGNORE_SIG))
    programming_error (_("trap_handler: bad signal %d"), sig);
  else
    {
      oerrno = errno;
#if defined (MUST_REINSTALL_SIGHANDLERS)
#  if defined (JOB_CONTROL) && defined (SIGCHLD)
      if (sig != SIGCHLD)
#  endif /* JOB_CONTROL && SIGCHLD */
      set_signal_handler (sig, trap_handler);
#endif /* MUST_REINSTALL_SIGHANDLERS */

      catch_flag = 1;
      pending_traps[sig]++;

      if (interrupt_immediately && this_shell_builtin && (this_shell_builtin == wait_builtin))
	{
	  wait_signal_received = sig;
	  longjmp (wait_intr_buf, 1);
	}

      if (interrupt_immediately)
	run_pending_traps ();

      errno = oerrno;
    }

  SIGRETURN (0);
}

#if defined (JOB_CONTROL) && defined (SIGCHLD)

#ifdef INCLUDE_UNUSED
/* Make COMMAND_STRING be executed when SIGCHLD is caught. */
void
set_sigchld_trap (command_string)
     char *command_string;
{
  set_signal (SIGCHLD, command_string);
}
#endif

/* Make COMMAND_STRING be executed when SIGCHLD is caught iff SIGCHLD
   is not already trapped.  IMPOSSIBLE_TRAP_HANDLER is used as a sentinel
   to make sure that a SIGCHLD trap handler run via run_sigchld_trap can
   reset the disposition to the default and not have the original signal
   accidentally restored, undoing the user's command. */
void
maybe_set_sigchld_trap (command_string)
     char *command_string;
{
  if ((sigmodes[SIGCHLD] & SIG_TRAPPED) == 0 && trap_list[SIGCHLD] == (char *)IMPOSSIBLE_TRAP_HANDLER)
    set_signal (SIGCHLD, command_string);
}

/* Temporarily set the SIGCHLD trap string to IMPOSSIBLE_TRAP_HANDLER.  Used
   as a sentinel in run_sigchld_trap and maybe_set_sigchld_trap to see whether
   or not a SIGCHLD trap handler reset SIGCHLD disposition to the default. */
void
set_impossible_sigchld_trap ()
{
  restore_default_signal (SIGCHLD);
  change_signal (SIGCHLD, (char *)IMPOSSIBLE_TRAP_HANDLER);
  sigmodes[SIGCHLD] &= ~SIG_TRAPPED;	/* maybe_set_sigchld_trap checks this */
}
#endif /* JOB_CONTROL && SIGCHLD */

void
set_debug_trap (command)
     char *command;
{
  set_signal (DEBUG_TRAP, command);
}

void
set_error_trap (command)
     char *command;
{
  set_signal (ERROR_TRAP, command);
}

void
set_return_trap (command)
     char *command;
{
  set_signal (RETURN_TRAP, command);
}

#ifdef INCLUDE_UNUSED
void
set_sigint_trap (command)
     char *command;
{
  set_signal (SIGINT, command);
}
#endif

/* Reset the SIGINT handler so that subshells that are doing `shellsy'
   things, like waiting for command substitution or executing commands
   in explicit subshells ( ( cmd ) ), can catch interrupts properly. */
SigHandler *
set_sigint_handler ()
{
  if (sigmodes[SIGINT] & SIG_HARD_IGNORE)
    return ((SigHandler *)SIG_IGN);

  else if (sigmodes[SIGINT] & SIG_IGNORED)
    return ((SigHandler *)set_signal_handler (SIGINT, SIG_IGN)); /* XXX */

  else if (sigmodes[SIGINT] & SIG_TRAPPED)
    return ((SigHandler *)set_signal_handler (SIGINT, trap_handler));

  /* The signal is not trapped, so set the handler to the shell's special
     interrupt handler. */
  else if (interactive)	/* XXX - was interactive_shell */
    return (set_signal_handler (SIGINT, sigint_sighandler));
  else
    return (set_signal_handler (SIGINT, termsig_sighandler));
}

/* Return the correct handler for signal SIG according to the values in
   sigmodes[SIG]. */
SigHandler *
trap_to_sighandler (sig)
     int sig;
{
  if (sigmodes[sig] & (SIG_IGNORED|SIG_HARD_IGNORE))
    return (SIG_IGN);
  else if (sigmodes[sig] & SIG_TRAPPED)
    return (trap_handler);
  else
    return (SIG_DFL);
}

/* Set SIG to call STRING as a command. */
void
set_signal (sig, string)
     int sig;
     char *string;
{
  if (SPECIAL_TRAP (sig))
    {
      change_signal (sig, savestring (string));
      if (sig == EXIT_TRAP && interactive == 0)
	initialize_terminating_signals ();
      return;
    }

  /* A signal ignored on entry to the shell cannot be trapped or reset, but
     no error is reported when attempting to do so.  -- Posix.2 */
  if (sigmodes[sig] & SIG_HARD_IGNORE)
    return;

  /* Make sure we have original_signals[sig] if the signal has not yet
     been trapped. */
  if ((sigmodes[sig] & SIG_TRAPPED) == 0)
    {
      /* If we aren't sure of the original value, check it. */
      if (original_signals[sig] == IMPOSSIBLE_TRAP_HANDLER)
        GETORIGSIG (sig);
      if (original_signals[sig] == SIG_IGN)
	return;
    }

  /* Only change the system signal handler if SIG_NO_TRAP is not set.
     The trap command string is changed in either case.  The shell signal
     handlers for SIGINT and SIGCHLD run the user specified traps in an
     environment in which it is safe to do so. */
  if ((sigmodes[sig] & SIG_NO_TRAP) == 0)
    {
      set_signal_handler (sig, SIG_IGN);
      change_signal (sig, savestring (string));
      set_signal_handler (sig, trap_handler);
    }
  else
    change_signal (sig, savestring (string));
}

static void
free_trap_command (sig)
     int sig;
{
  if ((sigmodes[sig] & SIG_TRAPPED) && trap_list[sig] &&
      (trap_list[sig] != (char *)IGNORE_SIG) &&
      (trap_list[sig] != (char *)DEFAULT_SIG) &&
      (trap_list[sig] != (char *)IMPOSSIBLE_TRAP_HANDLER))
    free (trap_list[sig]);
}

/* If SIG has a string assigned to it, get rid of it.  Then give it
   VALUE. */
static void
change_signal (sig, value)
     int sig;
     char *value;
{
  if ((sigmodes[sig] & SIG_INPROGRESS) == 0)
    free_trap_command (sig);
  trap_list[sig] = value;

  sigmodes[sig] |= SIG_TRAPPED;
  if (value == (char *)IGNORE_SIG)
    sigmodes[sig] |= SIG_IGNORED;
  else
    sigmodes[sig] &= ~SIG_IGNORED;
  if (sigmodes[sig] & SIG_INPROGRESS)
    sigmodes[sig] |= SIG_CHANGED;
}

static void
get_original_signal (sig)
     int sig;
{
  /* If we aren't sure the of the original value, then get it. */
  if (sig > 0 && sig < NSIG && original_signals[sig] == (SigHandler *)IMPOSSIBLE_TRAP_HANDLER)
    GETORIGSIG (sig);
}

void
get_all_original_signals ()
{
  register int i;

  for (i = 1; i < NSIG; i++)
    GET_ORIGINAL_SIGNAL (i);
}

void
set_original_signal (sig, handler)
     int sig;
     SigHandler *handler;
{
  if (sig > 0 && sig < NSIG && original_signals[sig] == (SigHandler *)IMPOSSIBLE_TRAP_HANDLER)
    SETORIGSIG (sig, handler);
}

/* Restore the default action for SIG; i.e., the action the shell
   would have taken before you used the trap command.  This is called
   from trap_builtin (), which takes care to restore the handlers for
   the signals the shell treats specially. */
void
restore_default_signal (sig)
     int sig;
{
  if (SPECIAL_TRAP (sig))
    {
      if ((sig != DEBUG_TRAP && sig != ERROR_TRAP && sig != RETURN_TRAP) ||
	  (sigmodes[sig] & SIG_INPROGRESS) == 0)
	free_trap_command (sig);
      trap_list[sig] = (char *)NULL;
      sigmodes[sig] &= ~SIG_TRAPPED;
      if (sigmodes[sig] & SIG_INPROGRESS)
	sigmodes[sig] |= SIG_CHANGED;
      return;
    }

  GET_ORIGINAL_SIGNAL (sig);

  /* A signal ignored on entry to the shell cannot be trapped or reset, but
     no error is reported when attempting to do so.  Thanks Posix.2. */
  if (sigmodes[sig] & SIG_HARD_IGNORE)
    return;

  /* If we aren't trapping this signal, don't bother doing anything else. */
  if ((sigmodes[sig] & SIG_TRAPPED) == 0)
    return;

  /* Only change the signal handler for SIG if it allows it. */
  if ((sigmodes[sig] & SIG_NO_TRAP) == 0)
    set_signal_handler (sig, original_signals[sig]);

  /* Change the trap command in either case. */
  change_signal (sig, (char *)DEFAULT_SIG);

  /* Mark the signal as no longer trapped. */
  sigmodes[sig] &= ~SIG_TRAPPED;
}

/* Make this signal be ignored. */
void
ignore_signal (sig)
     int sig;
{
  if (SPECIAL_TRAP (sig) && ((sigmodes[sig] & SIG_IGNORED) == 0))
    {
      change_signal (sig, (char *)IGNORE_SIG);
      return;
    }

  GET_ORIGINAL_SIGNAL (sig);

  /* A signal ignored on entry to the shell cannot be trapped or reset.
     No error is reported when the user attempts to do so. */
  if (sigmodes[sig] & SIG_HARD_IGNORE)
    return;

  /* If already trapped and ignored, no change necessary. */
  if (sigmodes[sig] & SIG_IGNORED)
    return;

  /* Only change the signal handler for SIG if it allows it. */
  if ((sigmodes[sig] & SIG_NO_TRAP) == 0)
    set_signal_handler (sig, SIG_IGN);

  /* Change the trap command in either case. */
  change_signal (sig, (char *)IGNORE_SIG);
}

/* Handle the calling of "trap 0".  The only sticky situation is when
   the command to be executed includes an "exit".  This is why we have
   to provide our own place for top_level to jump to. */
int
run_exit_trap ()
{
  char *trap_command;
  int code, function_code, retval;
#if defined (ARRAY_VARS)
  ARRAY *ps;
#endif

  trap_saved_exit_value = last_command_exit_value;
#if defined (ARRAY_VARS)
  ps = save_pipestatus_array ();
#endif
  function_code = 0;

  /* Run the trap only if signal 0 is trapped and not ignored, and we are not
     currently running in the trap handler (call to exit in the list of
     commands given to trap 0). */
  if ((sigmodes[EXIT_TRAP] & SIG_TRAPPED) &&
      (sigmodes[EXIT_TRAP] & (SIG_IGNORED|SIG_INPROGRESS)) == 0)
    {
      trap_command = savestring (trap_list[EXIT_TRAP]);
      sigmodes[EXIT_TRAP] &= ~SIG_TRAPPED;
      sigmodes[EXIT_TRAP] |= SIG_INPROGRESS;

      retval = trap_saved_exit_value;
      running_trap = 1;

      code = setjmp (top_level);

      /* If we're in a function, make sure return longjmps come here, too. */
      if (return_catch_flag)
	function_code = setjmp (return_catch);

      if (code == 0 && function_code == 0)
	{
	  reset_parser ();
	  parse_and_execute (trap_command, "exit trap", SEVAL_NONINT|SEVAL_NOHIST|SEVAL_RESETLINE);
	}
      else if (code == ERREXIT)
	retval = last_command_exit_value;
      else if (code == EXITPROG)
	retval = last_command_exit_value;
      else if (function_code != 0)
        retval = return_catch_value;
      else