summaryrefslogtreecommitdiff
path: root/bin/ksh/c_sh.c
blob: 32e692674cef13a4a9f8f575a57f8d451036ec0b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
/*	$OpenBSD: c_sh.c,v 1.65 2023/09/14 18:32:03 cheloha Exp $	*/

/*
 * built-in Bourne commands
 */

#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/time.h>

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "sh.h"

static void p_tv(struct shf *, int, struct timeval *, int, char *, char *);
static void p_ts(struct shf *, int, struct timespec *, int, char *, char *);

/* :, false and true */
int
c_label(char **wp)
{
	return wp[0][0] == 'f' ? 1 : 0;
}

int
c_shift(char **wp)
{
	struct block *l = genv->loc;
	int n;
	int64_t val;
	char *arg;

	if (ksh_getopt(wp, &builtin_opt, null) == '?')
		return 1;
	arg = wp[builtin_opt.optind];

	if (arg) {
		evaluate(arg, &val, KSH_UNWIND_ERROR, false);
		n = val;
	} else
		n = 1;
	if (n < 0) {
		bi_errorf("%s: bad number", arg);
		return (1);
	}
	if (l->argc < n) {
		bi_errorf("nothing to shift");
		return (1);
	}
	l->argv[n] = l->argv[0];
	l->argv += n;
	l->argc -= n;
	return 0;
}

int
c_umask(char **wp)
{
	int i;
	char *cp;
	int symbolic = 0;
	mode_t old_umask;
	int optc;

	while ((optc = ksh_getopt(wp, &builtin_opt, "S")) != -1)
		switch (optc) {
		case 'S':
			symbolic = 1;
			break;
		case '?':
			return 1;
		}
	cp = wp[builtin_opt.optind];
	if (cp == NULL) {
		old_umask = umask(0);
		umask(old_umask);
		if (symbolic) {
			char buf[18];
			int j;

			old_umask = ~old_umask;
			cp = buf;
			for (i = 0; i < 3; i++) {
				*cp++ = "ugo"[i];
				*cp++ = '=';
				for (j = 0; j < 3; j++)
					if (old_umask & (1 << (8 - (3*i + j))))
						*cp++ = "rwx"[j];
				*cp++ = ',';
			}
			cp[-1] = '\0';
			shprintf("%s\n", buf);
		} else
			shprintf("%#3.3o\n", old_umask);
	} else {
		mode_t new_umask;

		if (digit(*cp)) {
			for (new_umask = 0; *cp >= '0' && *cp <= '7'; cp++)
				new_umask = new_umask * 8 + (*cp - '0');
			if (*cp) {
				bi_errorf("bad number");
				return 1;
			}
		} else {
			/* symbolic format */
			int positions, new_val;
			char op;

			old_umask = umask(0);
			umask(old_umask); /* in case of error */
			old_umask = ~old_umask;
			new_umask = old_umask;
			positions = 0;
			while (*cp) {
				while (*cp && strchr("augo", *cp))
					switch (*cp++) {
					case 'a':
						positions |= 0111;
						break;
					case 'u':
						positions |= 0100;
						break;
					case 'g':
						positions |= 0010;
						break;
					case 'o':
						positions |= 0001;
						break;
					}
				if (!positions)
					positions = 0111; /* default is a */
				if (!strchr("=+-", op = *cp))
					break;
				cp++;
				new_val = 0;
				while (*cp && strchr("rwxugoXs", *cp))
					switch (*cp++) {
					case 'r': new_val |= 04; break;
					case 'w': new_val |= 02; break;
					case 'x': new_val |= 01; break;
					case 'u': new_val |= old_umask >> 6;
						  break;
					case 'g': new_val |= old_umask >> 3;
						  break;
					case 'o': new_val |= old_umask >> 0;
						  break;
					case 'X': if (old_umask & 0111)
							new_val |= 01;
						  break;
					case 's': /* ignored */
						  break;
					}
				new_val = (new_val & 07) * positions;
				switch (op) {
				case '-':
					new_umask &= ~new_val;
					break;
				case '=':
					new_umask = new_val |
					    (new_umask & ~(positions * 07));
					break;
				case '+':
					new_umask |= new_val;
				}
				if (*cp == ',') {
					positions = 0;
					cp++;
				} else if (!strchr("=+-", *cp))
					break;
			}
			if (*cp) {
				bi_errorf("bad mask");
				return 1;
			}
			new_umask = ~new_umask;
		}
		umask(new_umask);
	}
	return 0;
}

int
c_dot(char **wp)
{
	char *file, *cp;
	char **argv;
	int argc;
	int i;
	int err;

	if (ksh_getopt(wp, &builtin_opt, null) == '?')
		return 1;

	if ((cp = wp[builtin_opt.optind]) == NULL)
		return 0;
	file = search(cp, search_path, R_OK, &err);
	if (file == NULL) {
		bi_errorf("%s: %s", cp, err ? strerror(err) : "not found");
		return 1;
	}

	/* Set positional parameters? */
	if (wp[builtin_opt.optind + 1]) {
		argv = wp + builtin_opt.optind;
		argv[0] = genv->loc->argv[0]; /* preserve $0 */
		for (argc = 0; argv[argc + 1]; argc++)
			;
	} else {
		argc = 0;
		argv = NULL;
	}
	i = include(file, argc, argv, 0);
	if (i < 0) { /* should not happen */
		bi_errorf("%s: %s", cp, strerror(errno));
		return 1;
	}
	return i;
}

int
c_wait(char **wp)
{
	int rv = 0;
	int sig;

	if (ksh_getopt(wp, &builtin_opt, null) == '?')
		return 1;
	wp += builtin_opt.optind;
	if (*wp == NULL) {
		while (waitfor(NULL, &sig) >= 0)
			;
		rv = sig;
	} else {
		for (; *wp; wp++)
			rv = waitfor(*wp, &sig);
		if (rv < 0)
			rv = sig ? sig : 127; /* magic exit code: bad job-id */
	}
	return rv;
}

int
c_read(char **wp)
{
	int c = 0;
	int expand = 1, savehist = 0;
	int expanding;
	int ecode = 0;
	char *cp;
	int fd = 0;
	struct shf *shf;
	int optc;
	const char *emsg;
	XString cs, xs;
	struct tbl *vp;
	char *xp = NULL;

	while ((optc = ksh_getopt(wp, &builtin_opt, "prsu,")) != -1)
		switch (optc) {
		case 'p':
			if ((fd = coproc_getfd(R_OK, &emsg)) < 0) {
				bi_errorf("-p: %s", emsg);
				return 1;
			}
			break;
		case 'r':
			expand = 0;
			break;
		case 's':
			savehist = 1;
			break;
		case 'u':
			if (!*(cp = builtin_opt.optarg))
				fd = 0;
			else if ((fd = check_fd(cp, R_OK, &emsg)) < 0) {
				bi_errorf("-u: %s: %s", cp, emsg);
				return 1;
			}
			break;
		case '?':
			return 1;
		}
	wp += builtin_opt.optind;

	if (*wp == NULL)
		*--wp = "REPLY";

	/* Since we can't necessarily seek backwards on non-regular files,
	 * don't buffer them so we can't read too much.
	 */
	shf = shf_reopen(fd, SHF_RD | SHF_INTERRUPT | can_seek(fd), shl_spare);

	if ((cp = strchr(*wp, '?')) != NULL) {
		*cp = 0;
		if (isatty(fd)) {
			/* at&t ksh says it prints prompt on fd if it's open
			 * for writing and is a tty, but it doesn't do it
			 * (it also doesn't check the interactive flag,
			 * as is indicated in the Kornshell book).
			 */
			shellf("%s", cp+1);
		}
	}

	/* If we are reading from the co-process for the first time,
	 * make sure the other side of the pipe is closed first.  This allows
	 * the detection of eof.
	 *
	 * This is not compatible with at&t ksh... the fd is kept so another
	 * coproc can be started with same output, however, this means eof
	 * can't be detected...  This is why it is closed here.
	 * If this call is removed, remove the eof check below, too.
	 * coproc_readw_close(fd);
	 */

	if (savehist)
		Xinit(xs, xp, 128, ATEMP);
	expanding = 0;
	Xinit(cs, cp, 128, ATEMP);
	for (; *wp != NULL; wp++) {
		for (cp = Xstring(cs, cp); ; ) {
			if (c == '\n' || c == EOF)
				break;
			while (1) {
				c = shf_getc(shf);
				if (c == '\0')
					continue;
				if (c == EOF && shf_error(shf) &&
				    shf->errno_ == EINTR) {
					/* Was the offending signal one that
					 * would normally kill a process?
					 * If so, pretend the read was killed.
					 */
					ecode = fatal_trap_check();

					/* non fatal (eg, CHLD), carry on */
					if (!ecode) {
						shf_clearerr(shf);
						continue;
					}
				}
				break;
			}
			if (savehist) {
				Xcheck(xs, xp);
				Xput(xs, xp, c);
			}
			Xcheck(cs, cp);
			if (expanding) {
				expanding = 0;
				if (c == '\n') {
					c = 0;
					if (Flag(FTALKING_I) && isatty(fd)) {
						/* set prompt in case this is
						 * called from .profile or $ENV
						 */
						set_prompt(PS2);
						pprompt(prompt, 0);
					}
				} else if (c != EOF)
					Xput(cs, cp, c);
				continue;
			}
			if (expand && c == '\\') {
				expanding = 1;
				continue;
			}
			if (c == '\n' || c == EOF)
				break;
			if (ctype(c, C_IFS)) {
				if (Xlength(cs, cp) == 0 && ctype(c, C_IFSWS))
					continue;
				if (wp[1])
					break;
			}
			Xput(cs, cp, c);
		}
		/* strip trailing IFS white space from last variable */
		if (!wp[1])
			while (Xlength(cs, cp) && ctype(cp[-1], C_IFS) &&
			    ctype(cp[-1], C_IFSWS))
				cp--;
		Xput(cs, cp, '\0');
		vp = global(*wp);
		/* Must be done before setting export. */
		if (vp->flag & RDONLY) {
			shf_flush(shf);
			bi_errorf("%s is read only", *wp);
			return 1;
		}
		if (Flag(FEXPORT))
			typeset(*wp, EXPORT, 0, 0, 0);
		if (!setstr(vp, Xstring(cs, cp), KSH_RETURN_ERROR)) {
		    shf_flush(shf);
		    return 1;
		}
	}

	shf_flush(shf);
	if (savehist) {
		Xput(xs, xp, '\0');
		source->line++;
		histsave(source->line, Xstring(xs, xp), 1);
		Xfree(xs, xp);
	}
	/* if this is the co-process fd, close the file descriptor
	 * (can get eof if and only if all processes are have died, ie,
	 * coproc.njobs is 0 and the pipe is closed).
	 */
	if (c == EOF && !ecode)
		coproc_read_close(fd);

	return ecode ? ecode : c == EOF;
}

int
c_eval(char **wp)
{
	struct source *s;
	struct source *saves = source;
	int savef;
	int rv;

	if (ksh_getopt(wp, &builtin_opt, null) == '?')
		return 1;
	s = pushs(SWORDS, ATEMP);
	s->u.strv = wp + builtin_opt.optind;
	if (!Flag(FPOSIX)) {
		/*
		 * Handle case where the command is empty due to failed
		 * command substitution, eg, eval "$(false)".
		 * In this case, shell() will not set/change exstat (because
		 * compiled tree is empty), so will use this value.
		 * subst_exstat is cleared in execute(), so should be 0 if
		 * there were no substitutions.
		 *
		 * A strict reading of POSIX says we don't do this (though
		 * it is traditionally done). [from 1003.2-1992]
		 *    3.9.1: Simple Commands
		 *	... If there is a command name, execution shall
		 *	continue as described in 3.9.1.1.  If there
		 *	is no command name, but the command contained a command
		 *	substitution, the command shall complete with the exit
		 *	status of the last command substitution
		 *    3.9.1.1: Command Search and Execution
		 *	...(1)...(a) If the command name matches the name of
		 *	a special built-in utility, that special built-in
		 *	utility shall be invoked.
		 * 3.14.5: Eval
		 *	... If there are no arguments, or only null arguments,
		 *	eval shall return an exit status of zero.
		 */
		exstat = subst_exstat;
	}

	savef = Flag(FERREXIT);
	Flag(FERREXIT) = 0;
	rv = shell(s, false);
	Flag(FERREXIT) = savef;
	source = saves;
	afree(s, ATEMP);
	return (rv);
}

int
c_trap(char **wp)
{
	int i;
	char *s;
	Trap *p;

	if (ksh_getopt(wp, &builtin_opt, null) == '?')
		return 1;
	wp += builtin_opt.optind;

	if (*wp == NULL) {
		for (p = sigtraps, i = NSIG+1; --i >= 0; p++) {
			if (p->trap != NULL) {
				shprintf("trap -- ");
				print_value_quoted(p->trap);
				shprintf(" %s\n", p->name);
			}
		}
		return 0;
	}

	/*
	 * Use case sensitive lookup for first arg so the
	 * command 'exit' isn't confused with the pseudo-signal
	 * 'EXIT'.
	 */
	s = (gettrap(*wp, false) == NULL) ? *wp++ : NULL; /* get command */
	if (s != NULL && s[0] == '-' && s[1] == '\0')
		s = NULL;

	/* set/clear traps */
	while (*wp != NULL) {
		p = gettrap(*wp++, true);
		if (p == NULL) {
			bi_errorf("bad signal %s", wp[-1]);
			return 1;
		}
		settrap(p, s);
	}
	return 0;
}

int
c_exitreturn(char **wp)
{
	int how = LEXIT;
	int n;
	char *arg;

	if (ksh_getopt(wp, &builtin_opt, null) == '?')
		return 1;
	arg = wp[builtin_opt.optind];

	if (arg) {
		if (!getn(arg, &n)) {
			exstat = 1;
			warningf(true, "%s: bad number", arg);
		} else
			exstat = n;
	}
	if (wp[0][0] == 'r') { /* return */
		struct env *ep;

		/* need to tell if this is exit or return so trap exit will
		 * work right (POSIX)
		 */
		for (ep = genv; ep; ep = ep->oenv)
			if (STOP_RETURN(ep->type)) {
				how = LRETURN;
				break;
			}
	}

	if (how == LEXIT && !really_exit && j_stopped_running()) {
		really_exit = 1;
		how = LSHELL;
	}

	quitenv(NULL);	/* get rid of any i/o redirections */
	unwind(how);
	/* NOTREACHED */
	return 0;
}

int
c_brkcont(char **wp)
{
	int n, quit;
	struct env *ep, *last_ep = NULL;
	char *arg;

	if (ksh_getopt(wp, &builtin_opt, null) == '?')
		return 1;
	arg = wp[builtin_opt.optind];

	if (!arg)
		n = 1;
	else if (!bi_getn(arg, &n))
		return 1;
	quit = n;
	if (quit <= 0) {
		/* at&t ksh does this for non-interactive shells only - weird */
		bi_errorf("%s: bad value", arg);
		return 1;
	}

	/* Stop at E_NONE, E_PARSE, E_FUNC, or E_INCL */
	for (ep = genv; ep && !STOP_BRKCONT(ep->type); ep = ep->oenv)
		if (ep->type == E_LOOP) {
			if (--quit == 0)
				break;
			ep->flags |= EF_BRKCONT_PASS;
			last_ep = ep;
		}

	if (quit) {
		/* at&t ksh doesn't print a message - just does what it
		 * can.  We print a message 'cause it helps in debugging
		 * scripts, but don't generate an error (ie, keep going).
		 */
		if (n == quit) {
			warningf(true, "%s: cannot %s", wp[0], wp[0]);
			return 0;
		}
		/* POSIX says if n is too big, the last enclosing loop
		 * shall be used.  Doesn't say to print an error but we
		 * do anyway 'cause the user messed up.
		 */
		if (last_ep)
			last_ep->flags &= ~EF_BRKCONT_PASS;
		warningf(true, "%s: can only %s %d level(s)",
		    wp[0], wp[0], n - quit);
	}

	unwind(*wp[0] == 'b' ? LBREAK : LCONTIN);
	/* NOTREACHED */
}

int
c_set(char **wp)
{
	int argi, setargs;
	struct block *l = genv->loc;
	char **owp = wp;

	if (wp[1] == NULL) {
		static const char *const args [] = { "set", "-", NULL };
		return c_typeset((char **) args);
	}

	argi = parse_args(wp, OF_SET, &setargs);
	if (argi < 0)
		return 1;
	/* set $# and $* */
	if (setargs) {
		owp = wp += argi - 1;
		wp[0] = l->argv[0]; /* save $0 */
		while (*++wp != NULL)
			*wp = str_save(*wp, &l->area);
		l->argc = wp - owp - 1;
		l->argv = areallocarray(NULL, l->argc+2, sizeof(char *), &l->area);
		for (wp = l->argv; (*wp++ = *owp++) != NULL; )
			;
	}
	/* POSIX says set exit status is 0, but old scripts that use
	 * getopt(1), use the construct: set -- `getopt ab:c "$@"`
	 * which assumes the exit value set will be that of the ``
	 * (subst_exstat is cleared in execute() so that it will be 0
	 * if there are no command substitutions).
	 */
	return Flag(FPOSIX) ? 0 : subst_exstat;
}

int
c_unset(char **wp)
{
	char *id;
	int optc, unset_var = 1;

	while ((optc = ksh_getopt(wp, &builtin_opt, "fv")) != -1)
		switch (optc) {
		case 'f':
			unset_var = 0;
			break;
		case 'v':
			unset_var = 1;
			break;
		case '?':
			return 1;
		}
	wp += builtin_opt.optind;
	for (; (id = *wp) != NULL; wp++)
		if (unset_var) {	/* unset variable */
			struct tbl *vp = global(id);

			if ((vp->flag&RDONLY)) {
				bi_errorf("%s is read only", vp->name);
				return 1;
			}
			unset(vp, strchr(id, '[') ? 1 : 0);
		} else {		/* unset function */
			define(id, NULL);
		}
	return 0;
}

static void
p_tv(struct shf *shf, int posix, struct timeval *tv, int width, char *prefix,
    char *suffix)
{
	struct timespec ts;

	TIMEVAL_TO_TIMESPEC(tv, &ts);
	p_ts(shf, posix, &ts, width, prefix, suffix);
}

static void
p_ts(struct shf *shf, int posix, struct timespec *ts, int width, char *prefix,
    char *suffix)
{
	if (posix)
		shf_fprintf(shf, "%s%*lld.%02ld%s", prefix ? prefix : "",
		    width, (long long)ts->tv_sec, ts->tv_nsec / 10000000,
		    suffix);
	else
		shf_fprintf(shf, "%s%*lldm%02lld.%02lds%s", prefix ? prefix : "",
		    width, (long long)ts->tv_sec / 60,
		    (long long)ts->tv_sec % 60,
		    ts->tv_nsec / 10000000, suffix);
}


int
c_times(char **wp)
{
	struct rusage usage;

	(void) getrusage(RUSAGE_SELF, &usage);
	p_tv(shl_stdout, 0, &usage.ru_utime, 0, NULL, " ");
	p_tv(shl_stdout, 0, &usage.ru_stime, 0, NULL, "\n");

	(void) getrusage(RUSAGE_CHILDREN, &usage);
	p_tv(shl_stdout, 0, &usage.ru_utime, 0, NULL, " ");
	p_tv(shl_stdout, 0, &usage.ru_stime, 0, NULL, "\n");

	return 0;
}

/*
 * time pipeline (really a statement, not a built-in command)
 */
int
timex(struct op *t, int f, volatile int *xerrok)
{
#define TF_NOARGS	BIT(0)
#define TF_NOREAL	BIT(1)		/* don't report real time */
#define TF_POSIX	BIT(2)		/* report in posix format */
	int rv = 0;
	struct rusage ru0, ru1, cru0, cru1;
	struct timeval usrtime, systime;
	struct timespec ts0, ts1, ts2;
	int tf = 0;
	extern struct timeval j_usrtime, j_systime; /* computed by j_wait */

	clock_gettime(CLOCK_MONOTONIC, &ts0);
	getrusage(RUSAGE_SELF, &ru0);
	getrusage(RUSAGE_CHILDREN, &cru0);
	if (t->left) {
		/*
		 * Two ways of getting cpu usage of a command: just use t0
		 * and t1 (which will get cpu usage from other jobs that
		 * finish while we are executing t->left), or get the
		 * cpu usage of t->left. at&t ksh does the former, while
		 * pdksh tries to do the later (the j_usrtime hack doesn't
		 * really work as it only counts the last job).
		 */
		timerclear(&j_usrtime);
		timerclear(&j_systime);
		rv = execute(t->left, f | XTIME, xerrok);
		if (t->left->type == TCOM)
			tf |= t->left->str[0];
		clock_gettime(CLOCK_MONOTONIC, &ts1);
		getrusage(RUSAGE_SELF, &ru1);
		getrusage(RUSAGE_CHILDREN, &cru1);
	} else
		tf = TF_NOARGS;

	if (tf & TF_NOARGS) { /* ksh93 - report shell times (shell+kids) */
		tf |= TF_NOREAL;
		timeradd(&ru0.ru_utime, &cru0.ru_utime, &usrtime);
		timeradd(&ru0.ru_stime, &cru0.ru_stime, &systime);
	} else {
		timersub(&ru1.ru_utime, &ru0.ru_utime, &usrtime);
		timeradd(&usrtime, &j_usrtime, &usrtime);
		timersub(&ru1.ru_stime, &ru0.ru_stime, &systime);
		timeradd(&systime, &j_systime, &systime);
	}

	if (!(tf & TF_NOREAL)) {
		timespecsub(&ts1, &ts0, &ts2);
		if (tf & TF_POSIX)
			p_ts(shl_out, 1, &ts2, 5, "real ", "\n");
		else
			p_ts(shl_out, 0, &ts2, 5, NULL, " real ");
	}
	if (tf & TF_POSIX)
		p_tv(shl_out, 1, &usrtime, 5, "user ", "\n");
	else
		p_tv(shl_out, 0, &usrtime, 5, NULL, " user ");
	if (tf & TF_POSIX)
		p_tv(shl_out, 1, &systime, 5, "sys  ", "\n");
	else
		p_tv(shl_out, 0, &systime, 5, NULL, " system\n");
	shf_flush(shl_out);

	return rv;
}

void
timex_hook(struct op *t, char **volatile *app)
{
	char **wp = *app;
	int optc;
	int i, j;
	Getopt opt;

	ksh_getopt_reset(&opt, 0);
	opt.optind = 0;	/* start at the start */
	while ((optc = ksh_getopt(wp, &opt, ":p")) != -1)
		switch (optc) {
		case 'p':
			t->str[0] |= TF_POSIX;
			break;
		case '?':
			errorf("time: -%s unknown option", opt.optarg);
		case ':':
			errorf("time: -%s requires an argument",
			    opt.optarg);
		}
	/* Copy command words down over options. */
	if (opt.optind != 0) {
		for (i = 0; i < opt.optind; i++)
			afree(wp[i], ATEMP);
		for (i = 0, j = opt.optind; (wp[i] = wp[j]); i++, j++)
			;
	}
	if (!wp[0])
		t->str[0] |= TF_NOARGS;
	*app = wp;
}

/* exec with no args - args case is taken care of in comexec() */
int
c_exec(char **wp)
{
	int i;

	/* make sure redirects stay in place */
	if (genv->savefd != NULL) {
		for (i = 0; i < NUFILE; i++) {
			if (genv->savefd[i] > 0)
				close(genv->savefd[i]);
			/*
			 * For ksh keep anything > 2 private,
			 * for sh, let them be (POSIX says what
			 * happens is unspecified and the bourne shell
			 * keeps them open).
			 */
			if (!Flag(FSH) && i > 2 && genv->savefd[i])
				fcntl(i, F_SETFD, FD_CLOEXEC);
		}
		genv->savefd = NULL;
	}
	return 0;
}

static int
c_suspend(char **wp)
{
	if (wp[1] != NULL) {
		bi_errorf("too many arguments");
		return 1;
	}
	if (Flag(FLOGIN)) {
		/* Can't suspend an orphaned process group. */
		pid_t parent = getppid();
		if (getpgid(parent) == getpgid(0) ||
		    getsid(parent) != getsid(0)) {
			bi_errorf("can't suspend a login shell");
			return 1;
		}
	}
	j_suspend();
	return 0;
}

/* dummy function, special case in comexec() */
int
c_builtin(char **wp)
{
	return 0;
}

extern	int c_test(char **wp);			/* in c_test.c */
extern	int c_ulimit(char **wp);		/* in c_ulimit.c */

/* A leading = means assignments before command are kept;
 * a leading * means a POSIX special builtin;
 * a leading + means a POSIX regular builtin
 * (* and + should not be combined).
 */
const struct builtin shbuiltins [] = {
	{"*=.", c_dot},
	{"*=:", c_label},
	{"[", c_test},
	{"*=break", c_brkcont},
	{"=builtin", c_builtin},
	{"*=continue", c_brkcont},
	{"*=eval", c_eval},
	{"*=exec", c_exec},
	{"*=exit", c_exitreturn},
	{"+false", c_label},
	{"*=return", c_exitreturn},
	{"*=set", c_set},
	{"*=shift", c_shift},
	{"*=times", c_times},
	{"*=trap", c_trap},
	{"+=wait", c_wait},
	{"+read", c_read},
	{"test", c_test},
	{"+true", c_label},
	{"ulimit", c_ulimit},
	{"+umask", c_umask},
	{"*=unset", c_unset},
	{"suspend", c_suspend},
	{NULL, NULL}
};