3564ac65d4
when we try to set a trap on them it will not work. Also while I am here: 1. don't change the action status if the signal system call failed. 2. don't try to sigignore it if signal failed. 3. clear the signal mask in case our parent blocked it for us.
465 lines
8.9 KiB
C
465 lines
8.9 KiB
C
/* $NetBSD: trap.c,v 1.32 2005/07/11 02:37:05 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 1.32 2005/07/11 02:37:05 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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sig_t
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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, sig;
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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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/*
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* When we set a trap handler we want it to work,
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* even when our parent called us ignoring the
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* signal. This is what other shells do, so we
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* do not set S_HARD_IGN here.
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*/
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tsig = S_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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sig = signal(signo, sigact);
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if (sig != SIG_ERR) {
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sigset_t ss;
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if (!vforked)
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*t = action;
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if (action == S_CATCH)
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(void)siginterrupt(signo, 1);
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/*
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* If our parent accidentally blocked signals for
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* us make sure we unblock them
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*/
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(void)sigemptyset(&ss);
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(void)sigaddset(&ss, signo);
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(void)sigprocmask(SIG_UNBLOCK, &ss, NULL);
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}
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return sig;
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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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signal(signo, SIG_IGN);
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}
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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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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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