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    Length: 5167 (0x142f)
    Types: TextFile
    Names: »trap.c«

└─⟦a05ed705a⟧ Bits:30007078 DKUUG GNU 2/12/89
    └─⟦ca1f037a2⟧ »./bash-1.04.tar.Z« 
        └─⟦46465a4db⟧ 
            └─⟦this⟧ »bash-1.04/trap.c« 

TextFile

/* trap.c -- Not the trap command, but useful functions
   for manipulating those objects.  The trap command is
   in builtins.c */

/* Copyright (C) 1987,1989 Free Software Foundation, Inc.

This file is part of GNU Bash, the Bourne Again SHell.

Bash is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 1, or (at your option) any later
version.

Bash is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License along
with Bash; see the file COPYING.  If not, write to the Free Software
Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */

#include "trap.h"
#include "shell.h"

/* The list of things to do originally, before we started trapping. */
SigHandler *original_signals[NSIG];

/* For each signal, a slot for a string, which is a command to be
   executed when that signal is recieved.  The slot can also contain
   DEFAULT_SIG, which means do whatever you were going to do before
   you were so rudely interrupted, or IGNORE_SIG, which says ignore
   this signal. */
char *trap_list[NSIG];

/* A translation list so we can be polite to our users. */
char *signal_names[NSIG] = {
   "ON_EXIT",		/* `signal' 0 is what we do on exit. */
   "SIGHUP",		/* hangup */
   "SIGINT",		/* interrupt */
   "SIGQUIT",		/* quit */
   "SIGILL",		/* illegal instruction (not reset when caught) */
   "SIGTRAP",		/* trace trap (not reset when caught) */
#ifdef SIGABRT
   "SIGABRT",
#else
   "SIGIOT",		/* IOT instruction */
#endif
   "SIGEMT",		/* EMT instruction */
   "SIGFPE",		/* floating point exception */
   "SIGKILL",		/* kill (cannot be caught or ignored) */
   "SIGBUS",		/* bus error */
   "SIGSEGV",		/* segmentation violation */
   "SIGSYS",		/* bad argument to system call */
   "SIGPIPE",		/* write on a pipe with no one to read it */
   "SIGALRM",		/* alarm clock */
   "SIGTERM",		/* software termination signal from kill */
#ifdef SYSV
   "SIGUSR1",
   "SIGUSR2",
   "SIGCLD",
   "SIGPWR",
#if NSIG == 23
   "SIGJUNK1",
   "SIGJUNK2",
   "SIGPOLL"
#endif
#else
   "SIGURG",		/* urgent condition on IO channel */
   "SIGSTOP",		/* sendable stop signal not from tty */
   "SIGTSTP",		/* stop signal from tty */
   "SIGCONT",		/* continue a stopped process */
   "SIGCHLD",		/* to parent on child stop or exit */
   "SIGTTIN",		/* to readers pgrp upon background tty read */
   "SIGTTOU",		/* like TTIN for output if (tp->t_local&LTOSTOP) */
   "SIGIO",		/* input/output possible signal */
   "SIGXCPU",		/* exceeded CPU time limit */
   "SIGXFSZ",		/* exceeded file size limit */
   "SIGVTALRM",		/* virtual time alarm */
   "SIGPROF",		/* profiling time alarm */
   "SIGWINCH",		/* window changed */
   "SIGLOST",		/* resource lost (eg, record-lock lost) */
   "SIGUSR1",		/* user defined signal 1 */
   "SIGUSR2"		/* user defined signal 2 */
#endif
 };

initialize_traps ()
{
  register int i;

  for (i = 0; i < NSIG; i++) {
     trap_list[i] = (char *)DEFAULT_SIG;
     original_signals[i] = (SigHandler *)signal (i, SIG_DFL);
     signal (i, original_signals[i]);
   }
}

/* Return the print name of this signal. */
char *
signal_name (signal)
     int signal;
{
  if (signal > NSIG)
     return ("bad signal number");
  else return (signal_names[signal]);
}

/* Turn a string into a signal number, or a number into
   a signal number.  If STRING was "2", "SIGINT", or "INT",
   then (int)2 would be returned. */
int
decode_signal (string)
     char *string;
{
  int sig;

  if (sscanf (string, "%d", &sig) == 1) {
    if (sig < NSIG && sig >= 0)
      return (sig);
    else
      return (NO_SIG);
  }
      
  for (sig = 0; sig < NSIG; sig++)
     if ((strcmp (string, signal_names[sig]) == 0) ||
	 (strcmp (string, &(signal_names[sig])[3]) == 0))
       return (sig);
  return (NO_SIG);
}

sighandler
trap_handler (sig)
     int sig;
{
  if ((sig >= NSIG) || (((int)trap_list[sig]) == 0))
     programming_error ("trap_handler: Bad signal %d", sig);
  else
     parse_and_execute (savestring (trap_list[sig]), "trap");
}

/* Set SIG to call STRING as a command. */
void
set_signal (sig, string)
     int sig;
     char *string;
{
  void change_signal ();

  signal (sig, SIG_IGN);
  change_signal (sig, savestring (string));
  signal (sig, trap_handler);
}

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

/* Restore the default action for SIG; i.e., the action the shell
   would have taken before you used the trap command. */
void
restore_default_signal (sig)
     int sig;
{
  signal (sig, original_signals[sig]);
  change_signal (sig, (char *)DEFAULT_SIG);
}

/* Make this signal be ignored. */
void
ignore_signal (sig)
     int sig;
{
  signal (sig, SIG_IGN);
  change_signal (sig, (char *)IGNORE_SIG);
}