NetBSD/bin/sh/trap.c

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/* $NetBSD: trap.c,v 1.24 2000/05/22 10:18:47 elric Exp $ */
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/*-
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* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
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*
* This code is derived from software contributed to Berkeley by
* Kenneth Almquist.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
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#include <sys/cdefs.h>
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#ifndef lint
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#if 0
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 1.24 2000/05/22 10:18:47 elric Exp $");
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#endif
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#endif /* not lint */
#include <signal.h>
#include <unistd.h>
#include <stdlib.h>
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#include "shell.h"
#include "main.h"
#include "nodes.h" /* for other headers */
#include "eval.h"
#include "jobs.h"
#include "show.h"
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#include "options.h"
#include "syntax.h"
#include "output.h"
#include "memalloc.h"
#include "error.h"
#include "trap.h"
#include "mystring.h"
/*
* Sigmode records the current value of the signal handlers for the various
* modes. A value of zero means that the current handler is not known.
* S_HARD_IGN indicates that the signal was ignored on entry to the shell,
*/
#define S_DFL 1 /* default signal handling (SIG_DFL) */
#define S_CATCH 2 /* signal is caught */
#define S_IGN 3 /* signal is ignored (SIG_IGN) */
#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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extern char nullstr[1]; /* null string */
char *trap[NSIG+1]; /* trap handler commands */
MKINIT char sigmode[NSIG]; /* current value of signal */
char gotsig[NSIG]; /* indicates specified signal received */
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int pendingsigs; /* indicates some signal received */
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static int getsigaction __P((int, sig_t *));
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/*
* The trap builtin.
*/
int
trapcmd(argc, argv)
int argc;
char **argv;
{
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char *action;
char **ap;
int signo;
if (argc <= 1) {
for (signo = 0 ; signo <= NSIG ; signo++) {
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if (trap[signo] != NULL)
out1fmt("%d: %s\n", signo, trap[signo]);
}
return 0;
}
ap = argv + 1;
if (is_number(*ap))
action = NULL;
else
action = *ap++;
while (*ap) {
if ((signo = number(*ap)) < 0 || signo > NSIG)
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error("%s: bad trap", *ap);
INTOFF;
if (action)
action = savestr(action);
if (trap[signo])
ckfree(trap[signo]);
trap[signo] = action;
if (signo != 0)
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setsignal(signo);
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INTON;
ap++;
}
return 0;
}
/*
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* Clear traps on a fork.
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*/
void
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clear_traps() {
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char **tp;
for (tp = trap ; tp <= &trap[NSIG] ; tp++) {
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if (*tp && **tp) { /* trap not NULL or SIG_IGN */
INTOFF;
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ckfree(*tp);
*tp = NULL;
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if (tp != &trap[0])
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setsignal(tp - trap);
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INTON;
}
}
}
/*
* Set the signal handler for the specified signal. The routine figures
* out what it should be set to.
*/
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long
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setsignal(signo)
int signo;
{
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int action;
sig_t sigact = SIG_DFL;
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char *t;
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if ((t = trap[signo]) == NULL)
action = S_DFL;
else if (*t != '\0')
action = S_CATCH;
else
action = S_IGN;
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if (rootshell && action == S_DFL) {
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switch (signo) {
case SIGINT:
if (iflag || minusc || sflag == 0)
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action = S_CATCH;
break;
case SIGQUIT:
#ifdef DEBUG
{
extern int debug;
if (debug)
break;
}
#endif
/* FALLTHROUGH */
case SIGTERM:
if (iflag)
action = S_IGN;
break;
#if JOBS
case SIGTSTP:
case SIGTTOU:
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if (mflag)
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action = S_IGN;
break;
#endif
}
}
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t = &sigmode[signo - 1];
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if (*t == 0) {
/*
* current setting unknown
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*/
if (!getsigaction(signo, &sigact)) {
/*
* Pretend it worked; maybe we should give a warning
* here, but other shells don't. We don't alter
* sigmode, so that we retry every time.
*/
return 0;
}
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if (sigact == SIG_IGN) {
if (mflag && (signo == SIGTSTP ||
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signo == SIGTTIN || signo == SIGTTOU)) {
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*t = S_IGN; /* don't hard ignore these */
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} else
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*t = S_HARD_IGN;
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} else {
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*t = S_RESET; /* force to be set */
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}
}
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if (*t == S_HARD_IGN || *t == action)
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return 0;
switch (action) {
case S_DFL: sigact = SIG_DFL; break;
case S_CATCH: sigact = onsig; break;
case S_IGN: sigact = SIG_IGN; break;
}
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*t = action;
siginterrupt(signo, 1);
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return (long)signal(signo, sigact);
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}
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/*
* Return the current setting for sig w/o changing it.
*/
static int
getsigaction(signo, sigact)
int signo;
sig_t *sigact;
{
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struct sigaction sa;
if (sigaction(signo, (struct sigaction *)0, &sa) == -1)
return 0;
*sigact = (sig_t) sa.sa_handler;
return 1;
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}
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/*
* Ignore a signal.
*/
void
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ignoresig(signo)
int signo;
{
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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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sigmode[signo - 1] = S_HARD_IGN;
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}
#ifdef mkinit
INCLUDE <signal.h>
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INCLUDE "trap.h"
SHELLPROC {
char *sm;
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clear_traps();
for (sm = sigmode ; sm < sigmode + NSIG ; sm++) {
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if (*sm == S_IGN)
*sm = S_HARD_IGN;
}
}
#endif
/*
* Signal handler.
*/
void
onsig(signo)
int signo;
{
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signal(signo, onsig);
if (signo == SIGINT && trap[SIGINT] == NULL) {
onint();
return;
}
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gotsig[signo - 1] = 1;
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pendingsigs++;
}
/*
* Called to execute a trap. Perhaps we should avoid entering new trap
* handlers while we are executing a trap handler.
*/
void
dotrap() {
int i;
int savestatus;
for (;;) {
for (i = 1 ; ; i++) {
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if (gotsig[i - 1])
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break;
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;
evalstring(trap[i], 0);
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exitstatus=savestatus;
}
done:
pendingsigs = 0;
}
/*
* Controls whether the shell is interactive or not.
*/
void
setinteractive(on)
int on;
{
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static int is_interactive;
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if (on == is_interactive)
return;
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setsignal(SIGINT);
setsignal(SIGQUIT);
setsignal(SIGTERM);
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is_interactive = on;
}
/*
* Called to exit the shell.
*/
void
exitshell(status)
int status;
{
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struct jmploc loc1, loc2;
char *p;
TRACE(("exitshell(%d) pid=%d\n", status, getpid()));
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if (setjmp(loc1.loc)) {
goto l1;
}
if (setjmp(loc2.loc)) {
goto l2;
}
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handler = &loc1;
if ((p = trap[0]) != NULL && *p != '\0') {
trap[0] = NULL;
evalstring(p, 0);
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}
l1: handler = &loc2; /* probably unnecessary */
flushall();
#if JOBS
setjobctl(0);
#endif
l2: _exit(status);
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/* NOTREACHED */
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}