456 lines
8.8 KiB
C
456 lines
8.8 KiB
C
/* $NetBSD: trap.c,v 1.31 2005/01/11 19:38:57 christos Exp $ */
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/*-
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Kenneth Almquist.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#ifndef lint
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#if 0
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static char sccsid[] = "@(#)trap.c 8.5 (Berkeley) 6/5/95";
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#else
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__RCSID("$NetBSD: trap.c,v 1.31 2005/01/11 19:38:57 christos Exp $");
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#endif
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#endif /* not lint */
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#include <signal.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include "shell.h"
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#include "main.h"
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#include "nodes.h" /* for other headers */
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#include "eval.h"
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#include "jobs.h"
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#include "show.h"
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#include "options.h"
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#include "syntax.h"
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#include "output.h"
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#include "memalloc.h"
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#include "error.h"
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#include "trap.h"
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#include "mystring.h"
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#include "var.h"
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/*
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* Sigmode records the current value of the signal handlers for the various
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* modes. A value of zero means that the current handler is not known.
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* S_HARD_IGN indicates that the signal was ignored on entry to the shell,
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*/
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#define S_DFL 1 /* default signal handling (SIG_DFL) */
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#define S_CATCH 2 /* signal is caught */
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#define S_IGN 3 /* signal is ignored (SIG_IGN) */
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#define S_HARD_IGN 4 /* signal is ignored permenantly */
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#define S_RESET 5 /* temporary - to reset a hard ignored sig */
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char *trap[NSIG+1]; /* trap handler commands */
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MKINIT char sigmode[NSIG]; /* current value of signal */
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char gotsig[NSIG]; /* indicates specified signal received */
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int pendingsigs; /* indicates some signal received */
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static int getsigaction(int, sig_t *);
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/*
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* return the signal number described by `p' (as a number or a name)
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* or -1 if it isn't one
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*/
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static int
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signame_to_signum(const char *p)
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{
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int i;
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if (is_number(p))
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return number(p);
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if (strcasecmp(p, "exit") == 0 )
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return 0;
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if (strncasecmp(p, "sig", 3) == 0)
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p += 3;
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for (i = 0; i < NSIG; ++i)
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if (strcasecmp (p, sys_signame[i]) == 0)
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return i;
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return -1;
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}
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/*
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* Print a list of valid signal names
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*/
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static void
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printsignals(void)
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{
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int n;
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out1str("EXIT ");
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for (n = 1; n < NSIG; n++) {
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out1fmt("%s", sys_signame[n]);
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if ((n == NSIG/2) || n == (NSIG - 1))
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out1str("\n");
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else
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out1c(' ');
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}
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}
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/*
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* The trap builtin.
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*/
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int
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trapcmd(int argc, char **argv)
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{
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char *action;
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char **ap;
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int signo;
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if (argc <= 1) {
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for (signo = 0 ; signo <= NSIG ; signo++)
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if (trap[signo] != NULL) {
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out1fmt("trap -- ");
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print_quoted(trap[signo]);
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out1fmt(" %s\n",
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(signo) ? sys_signame[signo] : "EXIT");
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}
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return 0;
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}
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ap = argv + 1;
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action = NULL;
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if (strcmp(*ap, "--") == 0)
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if (*++ap == NULL)
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return 0;
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if (signame_to_signum(*ap) == -1) {
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if ((*ap)[0] == '-') {
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if ((*ap)[1] == '\0')
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ap++;
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else if ((*ap)[1] == 'l' && (*ap)[2] == '\0') {
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printsignals();
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return 0;
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}
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else
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error("bad option %s\n", *ap);
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}
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else
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action = *ap++;
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}
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while (*ap) {
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if (is_number(*ap))
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signo = number(*ap);
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else
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signo = signame_to_signum(*ap);
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if (signo < 0 || signo > NSIG)
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error("%s: bad trap", *ap);
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INTOFF;
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if (action)
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action = savestr(action);
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if (trap[signo])
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ckfree(trap[signo]);
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trap[signo] = action;
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if (signo != 0)
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setsignal(signo, 0);
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INTON;
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ap++;
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}
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return 0;
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}
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/*
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* Clear traps on a fork or vfork.
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* Takes one arg vfork, to tell it to not be destructive of
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* the parents variables.
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*/
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void
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clear_traps(int vforked)
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{
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char **tp;
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for (tp = trap ; tp <= &trap[NSIG] ; tp++) {
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if (*tp && **tp) { /* trap not NULL or SIG_IGN */
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INTOFF;
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if (!vforked) {
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ckfree(*tp);
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*tp = NULL;
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}
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if (tp != &trap[0])
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setsignal(tp - trap, vforked);
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INTON;
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}
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}
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}
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/*
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* Set the signal handler for the specified signal. The routine figures
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* out what it should be set to.
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*/
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long
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setsignal(int signo, int vforked)
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{
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int action;
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sig_t sigact = SIG_DFL;
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struct sigaction act, oact;
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char *t, tsig;
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if ((t = trap[signo]) == NULL)
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action = S_DFL;
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else if (*t != '\0')
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action = S_CATCH;
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else
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action = S_IGN;
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if (rootshell && !vforked && action == S_DFL) {
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switch (signo) {
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case SIGINT:
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if (iflag || minusc || sflag == 0)
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action = S_CATCH;
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break;
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case SIGQUIT:
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#ifdef DEBUG
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if (debug)
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break;
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#endif
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/* FALLTHROUGH */
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case SIGTERM:
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if (iflag)
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action = S_IGN;
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break;
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#if JOBS
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case SIGTSTP:
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case SIGTTOU:
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if (mflag)
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action = S_IGN;
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break;
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#endif
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}
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}
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t = &sigmode[signo - 1];
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tsig = *t;
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if (tsig == 0) {
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/*
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* current setting unknown
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*/
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if (!getsigaction(signo, &sigact)) {
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/*
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* Pretend it worked; maybe we should give a warning
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* here, but other shells don't. We don't alter
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* sigmode, so that we retry every time.
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*/
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return 0;
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}
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if (sigact == SIG_IGN) {
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if (mflag && (signo == SIGTSTP ||
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signo == SIGTTIN || signo == SIGTTOU)) {
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tsig = S_IGN; /* don't hard ignore these */
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} else
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tsig = S_HARD_IGN;
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} else {
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tsig = S_RESET; /* force to be set */
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}
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}
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if (tsig == S_HARD_IGN || tsig == action)
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return 0;
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switch (action) {
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case S_DFL: sigact = SIG_DFL; break;
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case S_CATCH: sigact = onsig; break;
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case S_IGN: sigact = SIG_IGN; break;
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}
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if (!vforked)
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*t = action;
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act.sa_handler = sigact;
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sigemptyset(&act.sa_mask);
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act.sa_flags = 0;
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#ifdef SA_INTERRUPT
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act.sa_flags |= SA_INTERRUPT;
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#endif
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if(sigaction(signo, &act, &oact) < 0)
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return (long) SIG_ERR;
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return (long) oact.sa_handler;
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}
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/*
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* Return the current setting for sig w/o changing it.
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*/
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static int
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getsigaction(int signo, sig_t *sigact)
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{
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struct sigaction sa;
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if (sigaction(signo, (struct sigaction *)0, &sa) == -1)
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return 0;
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*sigact = (sig_t) sa.sa_handler;
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return 1;
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}
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/*
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* Ignore a signal.
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*/
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void
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ignoresig(int signo, int vforked)
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{
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if (sigmode[signo - 1] != S_IGN && sigmode[signo - 1] != S_HARD_IGN)
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bsd_signal(signo, SIG_IGN);
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if (!vforked)
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sigmode[signo - 1] = S_HARD_IGN;
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}
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#ifdef mkinit
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INCLUDE <signal.h>
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INCLUDE "trap.h"
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SHELLPROC {
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char *sm;
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clear_traps(0);
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for (sm = sigmode ; sm < sigmode + NSIG ; sm++) {
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if (*sm == S_IGN)
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*sm = S_HARD_IGN;
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}
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}
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#endif
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/*
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* Signal handler.
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*/
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void
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onsig(int signo)
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{
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bsd_signal(signo, onsig);
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if (signo == SIGINT && trap[SIGINT] == NULL) {
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onint();
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return;
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}
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gotsig[signo - 1] = 1;
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pendingsigs++;
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}
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/*
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* Called to execute a trap. Perhaps we should avoid entering new trap
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* handlers while we are executing a trap handler.
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*/
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void
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dotrap(void)
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{
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int i;
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int savestatus;
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for (;;) {
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for (i = 1 ; ; i++) {
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if (gotsig[i - 1])
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break;
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if (i >= NSIG)
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goto done;
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}
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gotsig[i - 1] = 0;
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savestatus=exitstatus;
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evalstring(trap[i], 0);
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exitstatus=savestatus;
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}
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done:
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pendingsigs = 0;
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}
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/*
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* Controls whether the shell is interactive or not.
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*/
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void
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setinteractive(int on)
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{
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static int is_interactive;
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if (on == is_interactive)
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return;
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setsignal(SIGINT, 0);
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setsignal(SIGQUIT, 0);
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setsignal(SIGTERM, 0);
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is_interactive = on;
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}
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/*
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* Called to exit the shell.
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*/
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void
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exitshell(int status)
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{
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struct jmploc loc1, loc2;
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char *p;
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TRACE(("pid %d, exitshell(%d)\n", getpid(), status));
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if (setjmp(loc1.loc)) {
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goto l1;
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}
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if (setjmp(loc2.loc)) {
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goto l2;
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}
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handler = &loc1;
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if ((p = trap[0]) != NULL && *p != '\0') {
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trap[0] = NULL;
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evalstring(p, 0);
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}
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l1: handler = &loc2; /* probably unnecessary */
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flushall();
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#if JOBS
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setjobctl(0);
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#endif
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l2: _exit(status);
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/* NOTREACHED */
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}
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