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trap.c revision 1.49 
      1 /*	$NetBSD: trap.c,v 1.49 2018/12/05 22:25:38 kre Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1991, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * Kenneth Almquist.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. Neither the name of the University nor the names of its contributors
     19  *    may be used to endorse or promote products derived from this software
     20  *    without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  */
     34 
     35 #include <sys/cdefs.h>
     36 #ifndef lint
     37 #if 0
     38 static char sccsid[] = "@(#)trap.c	8.5 (Berkeley) 6/5/95";
     39 #else
     40 __RCSID("$NetBSD: trap.c,v 1.49 2018/12/05 22:25:38 kre Exp $");
     41 #endif
     42 #endif /* not lint */
     43 
     44 #include <signal.h>
     45 #include <unistd.h>
     46 #include <stdlib.h>
     47 #include <stdio.h>
     48 #include <errno.h>
     49 
     50 #include <sys/resource.h>
     51 
     52 #include "shell.h"
     53 #include "main.h"
     54 #include "nodes.h"	/* for other headers */
     55 #include "eval.h"
     56 #include "jobs.h"
     57 #include "show.h"
     58 #include "options.h"
     59 #include "builtins.h"
     60 #include "syntax.h"
     61 #include "output.h"
     62 #include "memalloc.h"
     63 #include "error.h"
     64 #include "trap.h"
     65 #include "mystring.h"
     66 #include "var.h"
     67 
     68 
     69 /*
     70  * Sigmode records the current value of the signal handlers for the various
     71  * modes.  A value of zero means that the current handler is not known.
     72  * S_HARD_IGN indicates that the signal was ignored on entry to the shell,
     73  */
     74 
     75 #define S_DFL 1			/* default signal handling (SIG_DFL) */
     76 #define S_CATCH 2		/* signal is caught */
     77 #define S_IGN 3			/* signal is ignored (SIG_IGN) */
     78 #define S_HARD_IGN 4		/* signal is ignored permenantly */
     79 #define S_RESET 5		/* temporary - to reset a hard ignored sig */
     80 
     81 
     82 MKINIT char sigmode[NSIG];	/* current value of signal */
     83 static volatile sig_atomic_t gotsig[NSIG];/* indicates specified signal received */
     84 volatile sig_atomic_t pendingsigs;	/* indicates some signal received */
     85 
     86 int traps_invalid;		/* in a subshell, but trap[] not yet cleared */
     87 static char * volatile trap[NSIG];	/* trap handler commands */
     88 static int in_dotrap;
     89 static int last_trapsig;
     90 
     91 static int exiting;		/* exitshell() has been done */
     92 static int exiting_status;	/* the status to use for exit() */
     93 
     94 static int getsigaction(int, sig_t *);
     95 STATIC const char *trap_signame(int);
     96 void printsignals(struct output *, int);
     97 
     98 /*
     99  * return the signal number described by `p' (as a number or a name)
    100  * or -1 if it isn't one
    101  */
    102 
    103 static int
    104 signame_to_signum(const char *p)
    105 {
    106 	int i;
    107 
    108 	if (is_number(p))
    109 		return number(p);
    110 
    111 	if (strcasecmp(p, "exit") == 0 )
    112 		return 0;
    113 
    114 	i = signalnumber(p);
    115 	if (i == 0)
    116 		i = -1;
    117 	return i;
    118 }
    119 
    120 /*
    121  * return the name of a signal used by the "trap" command
    122  */
    123 STATIC const char *
    124 trap_signame(int signo)
    125 {
    126 	static char nbuf[12];
    127 	const char *p;
    128 
    129 	if (signo == 0)
    130 		return "EXIT";
    131 	p = signalname(signo);
    132 	if (p != NULL)
    133 		return p;
    134 	(void)snprintf(nbuf, sizeof nbuf, "%d", signo);
    135 	return nbuf;
    136 }
    137 
    138 #if 0		/* Share the version of this in src/bin/kill/kill.c */
    139 /*
    140  * Print a list of valid signal names
    141  */
    142 void
    143 printsignals(struct output *out, int len)
    144 {
    145 	int n;
    146 
    147 	if (len != 0)
    148 		outc(' ', out);
    149 	for (n = 1; n < NSIG; n++) {
    150 		outfmt(out, "%s", trap_signame(n));
    151 		if ((n == NSIG/2) ||  n == (NSIG - 1))
    152 			outstr("\n", out);
    153 		else
    154 			outc(' ', out);
    155 	}
    156 }
    157 #endif
    158 
    159 /*
    160  * The trap builtin.
    161  */
    162 
    163 int
    164 trapcmd(int argc, char **argv)
    165 {
    166 	char *action;
    167 	char **ap;
    168 	int signo;
    169 	int errs = 0;
    170 	int printonly = 0;
    171 
    172 	ap = argv + 1;
    173 
    174 	CTRACE(DBG_TRAP, ("trapcmd: "));
    175 	if (argc == 2 && strcmp(*ap, "-l") == 0) {
    176 		CTRACE(DBG_TRAP, ("-l\n"));
    177 		out1str("EXIT");
    178 		printsignals(out1, 4);
    179 		return 0;
    180 	}
    181 	if (argc == 2 && strcmp(*ap, "-") == 0) {
    182 		CTRACE(DBG_TRAP, ("-\n"));
    183 		for (signo = 0; signo < NSIG; signo++) {
    184 			if (trap[signo] == NULL)
    185 				continue;
    186 			INTOFF;
    187 			ckfree(trap[signo]);
    188 			trap[signo] = NULL;
    189 			if (signo != 0)
    190 				setsignal(signo, 0);
    191 			INTON;
    192 		}
    193 		traps_invalid = 0;
    194 		return 0;
    195 	}
    196 	if (argc >= 2 && strcmp(*ap, "-p") == 0) {
    197 		CTRACE(DBG_TRAP, ("-p "));
    198 		printonly = 1;
    199 		ap++;
    200 		argc--;
    201 	}
    202 
    203 	if (argc > 1 && strcmp(*ap, "--") == 0) {
    204 		argc--;
    205 		ap++;
    206 	}
    207 
    208 	if (argc <= 1) {
    209 		int count;
    210 
    211 		CTRACE(DBG_TRAP, ("*all*\n"));
    212 		if (printonly) {
    213 			for (count = 0, signo = 0 ; signo < NSIG ; signo++)
    214 				if (trap[signo] == NULL) {
    215 					if (count == 0)
    216 						out1str("trap -- -");
    217 					out1fmt(" %s", trap_signame(signo));
    218 					/* oh! unlucky 13 */
    219 					if (++count >= 13) {
    220 						out1str("\n");
    221 						count = 0;
    222 					}
    223 				}
    224 			if (count)
    225 				out1str("\n");
    226 		}
    227 
    228 		for (count = 0, signo = 0 ; signo < NSIG ; signo++)
    229 			if (trap[signo] != NULL && trap[signo][0] == '\0') {
    230 				if (count == 0)
    231 					out1str("trap -- ''");
    232 				out1fmt(" %s", trap_signame(signo));
    233 				/*
    234 				 * the prefix is 10 bytes, with 4 byte
    235 				 * signal names (common) we have room in
    236 				 * the 70 bytes left on a normal line for
    237 				 * 70/(4+1) signals, that's 14, but to
    238 				 * allow for the occasional longer sig name
    239 				 * we output one less...
    240 				 */
    241 				if (++count >= 13) {
    242 					out1str("\n");
    243 					count = 0;
    244 				}
    245 			}
    246 		if (count)
    247 			out1str("\n");
    248 
    249 		for (signo = 0 ; signo < NSIG ; signo++)
    250 			if (trap[signo] != NULL && trap[signo][0] != '\0') {
    251 				out1str("trap -- ");
    252 				print_quoted(trap[signo]);
    253 				out1fmt(" %s\n", trap_signame(signo));
    254 			}
    255 
    256 		return 0;
    257 	}
    258 	CTRACE(DBG_TRAP, ("\n"));
    259 
    260 	action = NULL;
    261 
    262 	if (!printonly && traps_invalid)
    263 		free_traps();
    264 
    265 	if (!printonly && !is_number(*ap)) {
    266 		if ((*ap)[0] == '-' && (*ap)[1] == '\0')
    267 			ap++;			/* reset to default */
    268 		else
    269 			action = *ap++;		/* can be '' for "ignore" */
    270 		argc--;
    271 	}
    272 
    273 	if (argc < 2) {		/* there must be at least 1 condition */
    274 		out2str("Usage: trap [-l]\n"
    275 			"       trap -p [condition ...]\n"
    276 			"       trap action condition ...\n"
    277 			"       trap N condition ...\n");
    278 		return 2;
    279 	}
    280 
    281 
    282 	while (*ap) {
    283 		signo = signame_to_signum(*ap);
    284 
    285 		if (signo < 0 || signo >= NSIG) {
    286 			/* This is not a fatal error, so sayeth posix */
    287 			outfmt(out2, "trap: '%s' bad condition\n", *ap);
    288 			errs = 1;
    289 			ap++;
    290 			continue;
    291 		}
    292 		ap++;
    293 
    294 		if (printonly) {
    295 			out1str("trap -- ");
    296 			if (trap[signo] == NULL)
    297 				out1str("-");
    298 			else
    299 				print_quoted(trap[signo]);
    300 			out1fmt(" %s\n", trap_signame(signo));
    301 			continue;
    302 		}
    303 
    304 		INTOFF;
    305 		if (action)
    306 			action = savestr(action);
    307 
    308 		VTRACE(DBG_TRAP, ("trap for %d from %s%s%s to %s%s%s\n", signo,
    309 			trap[signo] ? "'" : "", trap[signo] ? trap[signo] : "-",
    310 			trap[signo] ? "'" : "", action ?  "'" : "",
    311 			action ? action : "-", action ?  "'" : ""));
    312 
    313 		if (trap[signo])
    314 			ckfree(trap[signo]);
    315 
    316 		trap[signo] = action;
    317 
    318 		if (signo != 0)
    319 			setsignal(signo, 0);
    320 		INTON;
    321 	}
    322 	return errs;
    323 }
    324 
    325 
    326 
    327 /*
    328  * Clear traps on a fork or vfork.
    329  * Takes one arg vfork, to tell it to not be destructive of
    330  * the parents variables.
    331  */
    332 void
    333 clear_traps(int vforked)
    334 {
    335 	char * volatile *tp;
    336 
    337 	VTRACE(DBG_TRAP, ("clear_traps(%d)\n", vforked));
    338 	if (!vforked)
    339 		traps_invalid = 1;
    340 
    341 	for (tp = &trap[1] ; tp < &trap[NSIG] ; tp++) {
    342 		if (*tp && **tp) {	/* trap not NULL or SIG_IGN */
    343 			INTOFF;
    344 			setsignal(tp - trap, vforked == 1);
    345 			INTON;
    346 		}
    347 	}
    348 	if (vforked == 2)
    349 		free_traps();
    350 }
    351 
    352 void
    353 free_traps(void)
    354 {
    355 	char * volatile *tp;
    356 
    357 	VTRACE(DBG_TRAP, ("free_traps%s\n", traps_invalid ? "(invalid)" : ""));
    358 	INTOFF;
    359 	for (tp = trap ; tp < &trap[NSIG] ; tp++)
    360 		if (*tp && **tp) {
    361 			ckfree(*tp);
    362 			*tp = NULL;
    363 		}
    364 	traps_invalid = 0;
    365 	INTON;
    366 }
    367 
    368 /*
    369  * See if there are any defined traps
    370  */
    371 int
    372 have_traps(void)
    373 {
    374 	char * volatile *tp;
    375 
    376 	if (traps_invalid)
    377 		return 0;
    378 
    379 	for (tp = trap ; tp < &trap[NSIG] ; tp++)
    380 		if (*tp && **tp)	/* trap not NULL or SIG_IGN */
    381 			return 1;
    382 	return 0;
    383 }
    384 
    385 /*
    386  * Set the signal handler for the specified signal.  The routine figures
    387  * out what it should be set to.
    388  */
    389 void
    390 setsignal(int signo, int vforked)
    391 {
    392 	int action;
    393 	sig_t sigact = SIG_DFL, sig;
    394 	char *t, tsig;
    395 
    396 	if ((t = trap[signo]) == NULL)
    397 		action = S_DFL;
    398 	else if (*t != '\0')
    399 		action = S_CATCH;
    400 	else
    401 		action = S_IGN;
    402 
    403 	VTRACE(DBG_TRAP, ("setsignal(%d%s) -> %d", signo,
    404 	    vforked ? ", VF" : "", action));
    405 	if (rootshell && !vforked && action == S_DFL) {
    406 		switch (signo) {
    407 		case SIGINT:
    408 			if (iflag || minusc || sflag == 0)
    409 				action = S_CATCH;
    410 			break;
    411 		case SIGQUIT:
    412 #ifdef DEBUG
    413 			if (debug)
    414 				break;
    415 #endif
    416 			/* FALLTHROUGH */
    417 		case SIGTERM:
    418 			if (rootshell && iflag)
    419 				action = S_IGN;
    420 			break;
    421 #if JOBS
    422 		case SIGTSTP:
    423 		case SIGTTOU:
    424 			if (rootshell && mflag)
    425 				action = S_IGN;
    426 			break;
    427 #endif
    428 		}
    429 	}
    430 
    431 	/*
    432 	 * Never let users futz with SIGCHLD
    433 	 * instead we will give them pseudo SIGCHLD's
    434 	 * when background jobs complete.
    435 	 */
    436 	if (signo == SIGCHLD)
    437 		action = S_DFL;
    438 
    439 	VTRACE(DBG_TRAP, (" -> %d", action));
    440 
    441 	t = &sigmode[signo];
    442 	tsig = *t;
    443 	if (tsig == 0) {
    444 		/*
    445 		 * current setting unknown
    446 		 */
    447 		if (!getsigaction(signo, &sigact)) {
    448 			/*
    449 			 * Pretend it worked; maybe we should give a warning
    450 			 * here, but other shells don't. We don't alter
    451 			 * sigmode, so that we retry every time.
    452 			 */
    453 			VTRACE(DBG_TRAP, (" getsigaction (%d)\n", errno));
    454 			return;
    455 		}
    456 		VTRACE(DBG_TRAP, (" [%s]%s%s", sigact==SIG_IGN ? "IGN" :
    457 		    sigact==SIG_DFL ? "DFL" : "caught",
    458 		    iflag ? "i" : "", mflag ? "m" : ""));
    459 
    460 		if (sigact == SIG_IGN) {
    461 			/*
    462 			 * POSIX 3.14.13 states that non-interactive shells
    463 			 * should ignore trap commands for signals that were
    464 			 * ignored upon entry, and leaves the behavior
    465 			 * unspecified for interactive shells. On interactive
    466 			 * shells, or if job control is on, and we have a job
    467 			 * control related signal, we allow the trap to work.
    468 			 *
    469 			 * This change allows us to be POSIX compliant, and
    470 			 * at the same time override the default behavior if
    471 			 * we need to by setting the interactive flag.
    472 			 */
    473 			if ((mflag && (signo == SIGTSTP ||
    474 			     signo == SIGTTIN || signo == SIGTTOU)) || iflag) {
    475 				tsig = S_IGN;
    476 			} else
    477 				tsig = S_HARD_IGN;
    478 		} else {
    479 			tsig = S_RESET;	/* force to be set */
    480 		}
    481 	}
    482 	VTRACE(DBG_TRAP, (" tsig=%d\n", tsig));
    483 
    484 	if (tsig == S_HARD_IGN || tsig == action)
    485 		return;
    486 
    487 	switch (action) {
    488 		case S_DFL:	sigact = SIG_DFL;	break;
    489 		case S_CATCH:  	sigact = onsig;		break;
    490 		case S_IGN:	sigact = SIG_IGN;	break;
    491 	}
    492 
    493 	sig = signal(signo, sigact);
    494 
    495 	if (sig != SIG_ERR) {
    496 		sigset_t ss;
    497 
    498 		if (!vforked)
    499 			*t = action;
    500 
    501 		if (action == S_CATCH)
    502 			(void)siginterrupt(signo, 1);
    503 		/*
    504 		 * If our parent accidentally blocked signals for
    505 		 * us make sure we unblock them
    506 		 */
    507 		(void)sigemptyset(&ss);
    508 		(void)sigaddset(&ss, signo);
    509 		(void)sigprocmask(SIG_UNBLOCK, &ss, NULL);
    510 	}
    511 	return;
    512 }
    513 
    514 /*
    515  * Return the current setting for sig w/o changing it.
    516  */
    517 static int
    518 getsigaction(int signo, sig_t *sigact)
    519 {
    520 	struct sigaction sa;
    521 
    522 	if (sigaction(signo, (struct sigaction *)0, &sa) == -1)
    523 		return 0;
    524 	*sigact = (sig_t) sa.sa_handler;
    525 	return 1;
    526 }
    527 
    528 /*
    529  * Ignore a signal.
    530  */
    531 
    532 void
    533 ignoresig(int signo, int vforked)
    534 {
    535 	if (sigmode[signo] == 0)
    536 		setsignal(signo, vforked);
    537 
    538 	VTRACE(DBG_TRAP, ("ignoresig(%d%s)\n", signo, vforked ? ", VF" : ""));
    539 	if (sigmode[signo] != S_IGN && sigmode[signo] != S_HARD_IGN) {
    540 		signal(signo, SIG_IGN);
    541 		if (!vforked)
    542 			sigmode[signo] = S_IGN;
    543 	}
    544 }
    545 
    546 char *
    547 child_trap(void)
    548 {
    549 	char * p;
    550 
    551 	p = trap[SIGCHLD];
    552 
    553 	if (p != NULL && *p == '\0')
    554 		p = NULL;
    555 
    556 	return p;
    557 }
    558 
    559 
    560 #ifdef mkinit
    561 INCLUDE <signal.h>
    562 INCLUDE "trap.h"
    563 INCLUDE "shell.h"
    564 INCLUDE "show.h"
    565 
    566 SHELLPROC {
    567 	char *sm;
    568 
    569 	INTOFF;
    570 	clear_traps(2);
    571 	for (sm = sigmode ; sm < sigmode + NSIG ; sm++) {
    572 		if (*sm == S_IGN) {
    573 			*sm = S_HARD_IGN;
    574 			VTRACE(DBG_TRAP, ("SHELLPROC: %d -> hard_ign\n",
    575 			    (sm - sigmode)));
    576 		}
    577 	}
    578 	INTON;
    579 }
    580 #endif
    581 
    582 
    583 
    584 /*
    585  * Signal handler.
    586  */
    587 
    588 void
    589 onsig(int signo)
    590 {
    591 	CTRACE(DBG_SIG, ("Signal %d, had: pending %d, gotsig[%d]=%d\n",
    592 	    signo, pendingsigs, signo, gotsig[signo]));
    593 
    594 	/*			This should not be needed.
    595 	signal(signo, onsig);
    596 	*/
    597 
    598 	if (signo == SIGINT && trap[SIGINT] == NULL) {
    599 		onint();
    600 		return;
    601 	}
    602 
    603 	/*
    604 	 * if the signal will do nothing, no point reporting it
    605 	 */
    606 	if (trap[signo] != NULL && trap[signo][0] != '\0' &&
    607 	    signo != SIGCHLD) {
    608 		gotsig[signo] = 1;
    609 		pendingsigs++;
    610 	}
    611 }
    612 
    613 
    614 
    615 /*
    616  * Called to execute a trap.  Perhaps we should avoid entering new trap
    617  * handlers while we are executing a trap handler.
    618  */
    619 
    620 void
    621 dotrap(void)
    622 {
    623 	int i;
    624 	char *tr;
    625 	int savestatus;
    626 	struct skipsave saveskip;
    627 
    628 	in_dotrap++;
    629 
    630 	CTRACE(DBG_TRAP, ("dotrap[%d]: %d pending, traps %sinvalid\n",
    631 	    in_dotrap, pendingsigs, traps_invalid ? "" : "not "));
    632 	for (;;) {
    633 		pendingsigs = 0;
    634 		for (i = 1 ; ; i++) {
    635 			if (i >= NSIG)
    636 				return;
    637 			if (gotsig[i])
    638 				break;
    639 		}
    640 		gotsig[i] = 0;
    641 
    642 		if (traps_invalid)
    643 			continue;
    644 
    645 		tr = trap[i];
    646 
    647 		CTRACE(DBG_TRAP|DBG_SIG, ("dotrap %d: %s%s%s\n", i,
    648 		    tr ? "\"" : "", tr ? tr : "NULL", tr ? "\"" : ""));
    649 
    650 		if (tr != NULL) {
    651 			last_trapsig = i;
    652 			save_skipstate(&saveskip);
    653 			savestatus = exitstatus;
    654 
    655 			tr = savestr(tr);	/* trap code may free trap[i] */
    656 			evalstring(tr, 0);
    657 			ckfree(tr);
    658 
    659 			if (current_skipstate() == SKIPNONE ||
    660 			    saveskip.state != SKIPNONE) {
    661 				restore_skipstate(&saveskip);
    662 				exitstatus = savestatus;
    663 			}
    664 		}
    665 	}
    666 
    667 	in_dotrap--;
    668 }
    669 
    670 int
    671 lastsig(void)
    672 {
    673 	int i;
    674 
    675 	for (i = NSIG; --i > 0; )
    676 		if (gotsig[i])
    677 			return i;
    678 	return SIGINT;	/* XXX */
    679 }
    680 
    681 /*
    682  * Controls whether the shell is interactive or not.
    683  */
    684 
    685 
    686 void
    687 setinteractive(int on)
    688 {
    689 	static int is_interactive;
    690 
    691 	if (on == is_interactive)
    692 		return;
    693 	setsignal(SIGINT, 0);
    694 	setsignal(SIGQUIT, 0);
    695 	setsignal(SIGTERM, 0);
    696 	is_interactive = on;
    697 }
    698 
    699 
    700 
    701 /*
    702  * Called to exit the shell.
    703  */
    704 void
    705 exitshell(int status)
    706 {
    707 	CTRACE(DBG_ERRS|DBG_PROCS|DBG_CMDS|DBG_TRAP,
    708 	    ("pid %d: exitshell(%d)\n", getpid(), status));
    709 
    710 	exiting = 1;
    711 	exiting_status = status;
    712 	exitshell_savedstatus();
    713 }
    714 
    715 void
    716 exitshell_savedstatus(void)
    717 {
    718 	struct jmploc loc;
    719 	char *p;
    720 	volatile int sig = 0;
    721 	int s;
    722 	sigset_t sigs;
    723 
    724 	CTRACE(DBG_ERRS|DBG_PROCS|DBG_CMDS|DBG_TRAP,
    725          ("pid %d: exitshell_savedstatus()%s $?=%d xs=%d dt=%d ts=%d\n",
    726 	    getpid(), exiting ? " exiting" : "", exitstatus,
    727 	    exiting_status, in_dotrap, last_trapsig));
    728 
    729 	if (!exiting) {
    730 		if (in_dotrap && last_trapsig) {
    731 			sig = last_trapsig;
    732 			exiting_status = sig + 128;
    733 		} else
    734 			exiting_status = exitstatus;
    735 	}
    736 	exitstatus = exiting_status;
    737 
    738 	if (!setjmp(loc.loc)) {
    739 		handler = &loc;
    740 
    741 		if (!traps_invalid && (p = trap[0]) != NULL && *p != '\0') {
    742 			reset_eval();
    743 			trap[0] = NULL;
    744 			VTRACE(DBG_TRAP, ("exit trap: \"%s\"\n", p));
    745 			evalstring(p, 0);
    746 		}
    747 	}
    748 
    749 	INTOFF;			/*  we're done, no more interrupts. */
    750 
    751 	if (!setjmp(loc.loc)) {
    752 		handler = &loc;		/* probably unnecessary */
    753 		flushall();
    754 #if JOBS
    755 		setjobctl(0);
    756 #endif
    757 	}
    758 
    759 	if ((s = sig) != 0 && s != SIGSTOP && s != SIGTSTP && s != SIGTTIN &&
    760 	    s != SIGTTOU) {
    761 		struct rlimit nocore;
    762 
    763 		/*
    764 		 * if the signal is of the core dump variety, don't...
    765 		 */
    766 		nocore.rlim_cur = nocore.rlim_max = 0;
    767 		(void) setrlimit(RLIMIT_CORE, &nocore);
    768 
    769 		signal(s, SIG_DFL);
    770 		sigemptyset(&sigs);
    771 		sigaddset(&sigs, s);
    772 		sigprocmask(SIG_UNBLOCK, &sigs, NULL);
    773 
    774 		kill(getpid(), s);
    775 	}
    776 	_exit(exiting_status);
    777 	/* NOTREACHED */
    778 }
    779