xref: /netbsd-src/bin/ksh/exec.c (revision 4b896b232495b7a9b8b94a1cf1e21873296d53b8)
1 /*	$NetBSD: exec.c,v 1.8 2003/06/23 11:38:56 agc Exp $	*/
2 
3 /*
4  * execute command tree
5  */
6 #include <sys/cdefs.h>
7 
8 #ifndef lint
9 __RCSID("$NetBSD: exec.c,v 1.8 2003/06/23 11:38:56 agc Exp $");
10 #endif
11 
12 
13 #include "sh.h"
14 #include "c_test.h"
15 #include <ctype.h>
16 #include "ksh_stat.h"
17 
18 /* Does ps4 get parameter substitutions done? */
19 #ifdef KSH
20 # define PS4_SUBSTITUTE(s)	substitute((s), 0)
21 #else
22 # define PS4_SUBSTITUTE(s)	(s)
23 #endif /* KSH */
24 
25 static int	comexec	 ARGS((struct op *t, struct tbl *volatile tp, char **ap,
26 			      int volatile flags));
27 static void	scriptexec ARGS((struct op *tp, char **ap));
28 static int	call_builtin ARGS((struct tbl *tp, char **wp));
29 static int	iosetup ARGS((struct ioword *iop, struct tbl *tp));
30 static int	herein ARGS((const char *content, int sub));
31 #ifdef KSH
32 static char 	*do_selectargs ARGS((char **ap, bool_t print_menu));
33 #endif /* KSH */
34 #ifdef KSH
35 static int	dbteste_isa ARGS((Test_env *te, Test_meta meta));
36 static const char *dbteste_getopnd ARGS((Test_env *te, Test_op op,
37 					 int do_eval));
38 static int	dbteste_eval ARGS((Test_env *te, Test_op op, const char *opnd1,
39 				const char *opnd2, int do_eval));
40 static void	dbteste_error ARGS((Test_env *te, int offset, const char *msg));
41 #endif /* KSH */
42 #ifdef OS2
43 static int	search_access1 ARGS((const char *path, int mode, int *errnop));
44 #endif /* OS2 */
45 
46 
47 /*
48  * handle systems that don't have F_SETFD
49  */
50 #ifndef F_SETFD
51 # ifndef MAXFD
52 #   define  MAXFD 64
53 # endif
54 /* a bit field would be smaller, but this will work */
55 static char clexec_tab[MAXFD+1];
56 #endif
57 
58 /*
59  * we now use this function always.
60  */
61 int
62 fd_clexec(fd)
63     int fd;
64 {
65 #ifndef F_SETFD
66 	if (fd >= 0 && fd < sizeof(clexec_tab)) {
67 		clexec_tab[fd] = 1;
68 		return 0;
69 	}
70 	return -1;
71 #else
72 	return fcntl(fd, F_SETFD, 1);
73 #endif
74 }
75 
76 
77 /*
78  * execute command tree
79  */
80 int
81 execute(t, flags)
82 	struct op * volatile t;
83 	volatile int flags;	/* if XEXEC don't fork */
84 {
85 	int i;
86 	volatile int rv = 0;
87 	volatile int rv_prop = 0; /* rv being propogated or newly generated? */
88 	int pv[2];
89 	char ** volatile ap;
90 	char *s, *cp;
91 	struct ioword **iowp;
92 	struct tbl *tp = NULL;
93 
94 	if (t == NULL)
95 		return 0;
96 
97 	/* Is this the end of a pipeline?  If so, we want to evaluate the
98 	 * command arguments
99 	bool_t eval_done = FALSE;
100 	if ((flags&XFORK) && !(flags&XEXEC) && (flags&XPCLOSE)) {
101 		eval_done = TRUE;
102 		tp = eval_execute_args(t, &ap);
103 	}
104 	 */
105 	if ((flags&XFORK) && !(flags&XEXEC) && t->type != TPIPE)
106 		return exchild(t, flags & ~XTIME, -1); /* run in sub-process */
107 
108 	newenv(E_EXEC);
109 	if (trap)
110 		runtraps(0);
111 
112 	if (t->type == TCOM) {
113 		/* Clear subst_exstat before argument expansion.  Used by
114 		 * null commands (see comexec() and c_eval()) and by c_set().
115 		 */
116 		subst_exstat = 0;
117 
118 		current_lineno = t->lineno;	/* for $LINENO */
119 
120 		/* POSIX says expand command words first, then redirections,
121 		 * and assignments last..
122 		 */
123 		ap = eval(t->args, t->u.evalflags | DOBLANK | DOGLOB | DOTILDE);
124 		if (flags & XTIME)
125 			/* Allow option parsing (bizarre, but POSIX) */
126 			timex_hook(t, &ap);
127 		if (Flag(FXTRACE) && ap[0]) {
128 			shf_fprintf(shl_out, "%s",
129 				PS4_SUBSTITUTE(str_val(global("PS4"))));
130 			for (i = 0; ap[i]; i++)
131 				shf_fprintf(shl_out, "%s%s", ap[i],
132 					ap[i + 1] ? space : newline);
133 			shf_flush(shl_out);
134 		}
135 		if (ap[0])
136 			tp = findcom(ap[0], FC_BI|FC_FUNC);
137 	}
138 	flags &= ~XTIME;
139 
140 	if (t->ioact != NULL || t->type == TPIPE || t->type == TCOPROC) {
141 		e->savefd = (short *) alloc(sizeofN(short, NUFILE), ATEMP);
142 		/* initialize to not redirected */
143 		memset(e->savefd, 0, sizeofN(short, NUFILE));
144 	}
145 
146 	/* do redirection, to be restored in quitenv() */
147 	if (t->ioact != NULL)
148 		for (iowp = t->ioact; *iowp != NULL; iowp++) {
149 			if (iosetup(*iowp, tp) < 0) {
150 				exstat = rv = 1;
151 				/* Redirection failures for special commands
152 				 * cause (non-interactive) shell to exit.
153 				 */
154 				if (tp && tp->type == CSHELL
155 				    && (tp->flag & SPEC_BI))
156 					errorf(null);
157 				/* Deal with FERREXIT, quitenv(), etc. */
158 				goto Break;
159 			}
160 		}
161 
162 	switch(t->type) {
163 	  case TCOM:
164 		rv = comexec(t, tp, ap, flags);
165 		break;
166 
167 	  case TPAREN:
168 		rv = execute(t->left, flags|XFORK);
169 		rv_prop = 1;
170 		break;
171 
172 	  case TPIPE:
173 		flags |= XFORK;
174 		flags &= ~XEXEC;
175 		e->savefd[0] = savefd(0, 0);
176 		(void) ksh_dup2(e->savefd[0], 0, FALSE); /* stdin of first */
177 		e->savefd[1] = savefd(1, 0);
178 		while (t->type == TPIPE) {
179 			openpipe(pv);
180 			(void) ksh_dup2(pv[1], 1, FALSE); /* stdout of curr */
181 			/* Let exchild() close pv[0] in child
182 			 * (if this isn't done, commands like
183 			 *    (: ; cat /etc/termcap) | sleep 1
184 			 *  will hang forever).
185 			 */
186 			exchild(t->left, flags|XPIPEO|XCCLOSE, pv[0]);
187 			(void) ksh_dup2(pv[0], 0, FALSE); /* stdin of next */
188 			closepipe(pv);
189 			flags |= XPIPEI;
190 			t = t->right;
191 		}
192 		restfd(1, e->savefd[1]); /* stdout of last */
193 		e->savefd[1] = 0; /* no need to re-restore this */
194 		/* Let exchild() close 0 in parent, after fork, before wait */
195 		i = exchild(t, flags|XPCLOSE, 0);
196 		if (!(flags&XBGND) && !(flags&XXCOM))
197 			rv = i;
198 		break;
199 
200 	  case TLIST:
201 		while (t->type == TLIST) {
202 			execute(t->left, flags & XERROK);
203 			t = t->right;
204 		}
205 		rv = execute(t, flags & XERROK);
206 		break;
207 
208 #ifdef KSH
209 	  case TCOPROC:
210 	  {
211 # ifdef JOB_SIGS
212 		sigset_t	omask;
213 # endif /* JOB_SIGS */
214 
215 # ifdef JOB_SIGS
216 		/* Block sigchild as we are using things changed in the
217 		 * signal handler
218 		 */
219 		sigprocmask(SIG_BLOCK, &sm_sigchld, &omask);
220 		e->type = E_ERRH;
221 		i = ksh_sigsetjmp(e->jbuf, 0);
222 		if (i) {
223 			sigprocmask(SIG_SETMASK, &omask, (sigset_t *) 0);
224 			quitenv();
225 			unwind(i);
226 			/*NOTREACHED*/
227 		}
228 # endif /* JOB_SIGS */
229 		/* Already have a (live) co-process? */
230 		if (coproc.job && coproc.write >= 0)
231 			errorf("coprocess already exists");
232 
233 		/* Can we re-use the existing co-process pipe? */
234 		coproc_cleanup(TRUE);
235 
236 		/* do this before opening pipes, in case these fail */
237 		e->savefd[0] = savefd(0, 0);
238 		e->savefd[1] = savefd(1, 0);
239 
240 		openpipe(pv);
241 		ksh_dup2(pv[0], 0, FALSE);
242 		close(pv[0]);
243 		coproc.write = pv[1];
244 		coproc.job = (void *) 0;
245 
246 		if (coproc.readw >= 0)
247 			ksh_dup2(coproc.readw, 1, FALSE);
248 		else {
249 			openpipe(pv);
250 			coproc.read = pv[0];
251 			ksh_dup2(pv[1], 1, FALSE);
252 			coproc.readw = pv[1];	 /* closed before first read */
253 			coproc.njobs = 0;
254 			/* create new coprocess id */
255 			++coproc.id;
256 		}
257 # ifdef JOB_SIGS
258 		sigprocmask(SIG_SETMASK, &omask, (sigset_t *) 0);
259 		e->type = E_EXEC; /* no more need for error handler */
260 # endif /* JOB_SIGS */
261 
262 		/* exchild() closes coproc.* in child after fork,
263 		 * will also increment coproc.njobs when the
264 		 * job is actually created.
265 		 */
266 		flags &= ~XEXEC;
267 		exchild(t->left, flags|XBGND|XFORK|XCOPROC|XCCLOSE,
268 			coproc.readw);
269 		break;
270 	  }
271 #endif /* KSH */
272 
273 	  case TASYNC:
274 		/* XXX non-optimal, I think - "(foo &)", forks for (),
275 		 * forks again for async...  parent should optimize
276 		 * this to "foo &"...
277 		 */
278 		rv = execute(t->left, (flags&~XEXEC)|XBGND|XFORK);
279 		break;
280 
281 	  case TOR:
282 	  case TAND:
283 		rv = execute(t->left, XERROK);
284 		if (t->right != NULL && (rv == 0) == (t->type == TAND))
285 			rv = execute(t->right, flags & XERROK);
286 		else
287 			flags |= XERROK;
288 		rv_prop = 1;
289 		break;
290 
291 	  case TBANG:
292 		rv = !execute(t->right, XERROK);
293 		break;
294 
295 #ifdef KSH
296 	  case TDBRACKET:
297 	    {
298 		Test_env te;
299 
300 		te.flags = TEF_DBRACKET;
301 		te.pos.wp = t->args;
302 		te.isa = dbteste_isa;
303 		te.getopnd = dbteste_getopnd;
304 		te.eval = dbteste_eval;
305 		te.error = dbteste_error;
306 
307 		rv = test_parse(&te);
308 		break;
309 	    }
310 #endif /* KSH */
311 
312 	  case TFOR:
313 #ifdef KSH
314 	  case TSELECT:
315 	    {
316 		volatile bool_t is_first = TRUE;
317 #endif /* KSH */
318 		ap = (t->vars != NULL) ?
319 			  eval(t->vars, DOBLANK|DOGLOB|DOTILDE)
320 			: e->loc->argv + 1;
321 		e->type = E_LOOP;
322 		while (1) {
323 			i = ksh_sigsetjmp(e->jbuf, 0);
324 			if (!i)
325 				break;
326 			if ((e->flags&EF_BRKCONT_PASS)
327 			    || (i != LBREAK && i != LCONTIN))
328 			{
329 				quitenv();
330 				unwind(i);
331 			} else if (i == LBREAK) {
332 				rv = 0;
333 				goto Break;
334 			}
335 		}
336 		rv = 0; /* in case of a continue */
337 		rv_prop = 1;
338 		if (t->type == TFOR) {
339 			while (*ap != NULL) {
340 				setstr(global(t->str), *ap++, KSH_UNWIND_ERROR);
341 				rv = execute(t->left, flags & XERROK);
342 			}
343 		}
344 #ifdef KSH
345 		else { /* TSELECT */
346 			for (;;) {
347 				if (!(cp = do_selectargs(ap, is_first))) {
348 					rv = 1;
349 					rv_prop = 0;
350 					break;
351 				}
352 				is_first = FALSE;
353 				setstr(global(t->str), cp, KSH_UNWIND_ERROR);
354 				rv = execute(t->left, flags & XERROK);
355 			}
356 		}
357 	    }
358 #endif /* KSH */
359 		break;
360 
361 	  case TWHILE:
362 	  case TUNTIL:
363 		e->type = E_LOOP;
364 		while (1) {
365 			i = ksh_sigsetjmp(e->jbuf, 0);
366 			if (!i)
367 				break;
368 			if ((e->flags&EF_BRKCONT_PASS)
369 			    || (i != LBREAK && i != LCONTIN))
370 			{
371 				quitenv();
372 				unwind(i);
373 			} else if (i == LBREAK) {
374 				rv = 0;
375 				goto Break;
376 			}
377 		}
378 		rv = 0; /* in case of a continue */
379 		while ((execute(t->left, XERROK) == 0) == (t->type == TWHILE))
380 			rv = execute(t->right, flags & XERROK);
381 		rv_prop = 1;
382 		break;
383 
384 	  case TIF:
385 	  case TELIF:
386 		if (t->right == NULL)
387 			break;	/* should be error */
388 		rv = execute(t->left, XERROK) == 0 ?
389 			execute(t->right->left, flags & XERROK) :
390 			execute(t->right->right, flags & XERROK);
391 		rv_prop = 1;
392 		break;
393 
394 	  case TCASE:
395 		cp = evalstr(t->str, DOTILDE);
396 		for (t = t->left; t != NULL && t->type == TPAT; t = t->right)
397 		    for (ap = t->vars; *ap; ap++)
398 			if ((s = evalstr(*ap, DOTILDE|DOPAT))
399 			    && gmatch(cp, s, FALSE))
400 				goto Found;
401 		break;
402 	  Found:
403 		rv = execute(t->left, flags & XERROK);
404 		rv_prop = 1;
405 		break;
406 
407 	  case TBRACE:
408 		rv = execute(t->left, flags & XERROK);
409 		rv_prop = 1;
410 		break;
411 
412 	  case TFUNCT:
413 		rv = define(t->str, t);
414 		break;
415 
416 	  case TTIME:
417 		/* Clear XEXEC so nested execute() call doesn't exit
418 		 * (allows "ls -l | time grep foo").
419 		 */
420 		rv = timex(t, flags & ~XEXEC);
421 		rv_prop = 1;
422 		break;
423 
424 	  case TEXEC:		/* an eval'd TCOM */
425 		s = t->args[0];
426 		ap = makenv();
427 #ifndef F_SETFD
428 		for (i = 0; i < sizeof(clexec_tab); i++)
429 			if (clexec_tab[i]) {
430 				close(i);
431 				clexec_tab[i] = 0;
432 			}
433 #endif
434 		restoresigs();
435 		cleanup_proc_env();
436 		/* XINTACT bit is for OS2 */
437 		ksh_execve(t->str, t->args, ap, (flags & XINTACT) ? 1 : 0);
438 		if (errno == ENOEXEC)
439 			scriptexec(t, ap);
440 		else
441 			errorf("%s: %s", s, strerror(errno));
442 	}
443     Break:
444 	exstat = rv;
445 
446 	quitenv();		/* restores IO */
447 	if ((flags&XEXEC)) {
448 		unwind(LEXIT);	/* exit child */
449 		/* NOTREACHED */
450 	}
451 	if (rv != 0 && !rv_prop && !(flags & XERROK)) {
452 		if (Flag(FERREXIT))
453 			unwind(LERROR);
454 		trapsig(SIGERR_);
455 	}
456 	return rv;
457 }
458 
459 /*
460  * execute simple command
461  */
462 
463 static int
464 comexec(t, tp, ap, flags)
465 	struct op *t;
466 	struct tbl *volatile tp;
467 	register char **ap;
468 	int volatile flags;
469 {
470 	int i;
471 	int rv = 0;
472 	register char *cp;
473 	register char **lastp;
474 	static struct op texec; /* Must be static (XXX but why?) */
475 	int type_flags;
476 	int keepasn_ok;
477 	int fcflags = FC_BI|FC_FUNC|FC_PATH;
478 #ifdef __GNUC__
479 	(void) &rv;
480 #endif
481 
482 #ifdef KSH
483 	/* snag the last argument for $_ XXX not the same as at&t ksh,
484 	 * which only seems to set $_ after a newline (but not in
485 	 * functions/dot scripts, but in interactive and scipt) -
486 	 * perhaps save last arg here and set it in shell()?.
487 	 */
488 	if (Flag(FTALKING) && *(lastp = ap)) {
489 		while (*++lastp)
490 			;
491 		/* setstr() can't fail here */
492 		setstr(typeset("_", LOCAL, 0, INTEGER, 0), *--lastp,
493 		       KSH_RETURN_ERROR);
494 	}
495 #endif /* KSH */
496 
497 	/* Deal with the shell builtins builtin, exec and command since
498 	 * they can be followed by other commands.  This must be done before
499 	 * we know if we should create a local block, which must be done
500 	 * before we can do a path search (in case the assignments change
501 	 * PATH).
502 	 * Odd cases:
503 	 *   FOO=bar exec > /dev/null		FOO is kept but not exported
504 	 *   FOO=bar exec foobar		FOO is exported
505 	 *   FOO=bar command exec > /dev/null	FOO is neither kept nor exported
506 	 *   FOO=bar command			FOO is neither kept nor exported
507 	 *   PATH=... foobar			use new PATH in foobar search
508 	 */
509 	keepasn_ok = 1;
510 	while (tp && tp->type == CSHELL) {
511 		fcflags = FC_BI|FC_FUNC|FC_PATH;/* undo effects of command */
512 		if (tp->val.f == c_builtin) {
513 			if ((cp = *++ap) == NULL) {
514 				tp = NULL;
515 				break;
516 			}
517 			tp = findcom(cp, FC_BI);
518 			if (tp == NULL)
519 				errorf("builtin: %s: not a builtin", cp);
520 			continue;
521 		} else if (tp->val.f == c_exec) {
522 			if (ap[1] == NULL)
523 				break;
524 			ap++;
525 			flags |= XEXEC;
526 		} else if (tp->val.f == c_command) {
527 			int optc, saw_p = 0;
528 
529 			/* Ugly dealing with options in two places (here and
530 			 * in c_command(), but such is life)
531 			 */
532 			ksh_getopt_reset(&builtin_opt, 0);
533 			while ((optc = ksh_getopt(ap, &builtin_opt, ":p"))
534 									== 'p')
535 				saw_p = 1;
536 			if (optc != EOF)
537 				break;	/* command -vV or something */
538 			/* don't look for functions */
539 			fcflags = FC_BI|FC_PATH;
540 			if (saw_p) {
541 				if (Flag(FRESTRICTED)) {
542 					warningf(TRUE,
543 						"command -p: restricted");
544 					rv = 1;
545 					goto Leave;
546 				}
547 				fcflags |= FC_DEFPATH;
548 			}
549 			ap += builtin_opt.optind;
550 			/* POSIX says special builtins lose their status
551 			 * if accessed using command.
552 			 */
553 			keepasn_ok = 0;
554 			if (!ap[0]) {
555 				/* ensure command with no args exits with 0 */
556 				subst_exstat = 0;
557 				break;
558 			}
559 		} else
560 			break;
561 		tp = findcom(ap[0], fcflags & (FC_BI|FC_FUNC));
562 	}
563 	if (keepasn_ok && (!ap[0] || (tp && (tp->flag & KEEPASN))))
564 		type_flags = 0;
565 	else {
566 		/* create new variable/function block */
567 		newblock();
568 		/* ksh functions don't keep assignments, POSIX functions do. */
569 		if (keepasn_ok && tp && tp->type == CFUNC
570 		    && !(tp->flag & FKSH))
571 			type_flags = 0;
572 		else
573 			type_flags = LOCAL|LOCAL_COPY|EXPORT;
574 	}
575 	if (Flag(FEXPORT))
576 		type_flags |= EXPORT;
577 	for (i = 0; t->vars[i]; i++) {
578 		cp = evalstr(t->vars[i], DOASNTILDE);
579 		if (Flag(FXTRACE)) {
580 			if (i == 0)
581 				shf_fprintf(shl_out, "%s",
582 					PS4_SUBSTITUTE(str_val(global("PS4"))));
583 			shf_fprintf(shl_out, "%s%s", cp,
584 				t->vars[i + 1] ? space : newline);
585 			if (!t->vars[i + 1])
586 				shf_flush(shl_out);
587 		}
588 		typeset(cp, type_flags, 0, 0, 0);
589 	}
590 
591 	if ((cp = *ap) == NULL) {
592 		rv = subst_exstat;
593 		goto Leave;
594 	} else if (!tp) {
595 		if (Flag(FRESTRICTED) && ksh_strchr_dirsep(cp)) {
596 			warningf(TRUE, "%s: restricted", cp);
597 			rv = 1;
598 			goto Leave;
599 		}
600 		tp = findcom(cp, fcflags);
601 	}
602 
603 	switch (tp->type) {
604 	  case CSHELL:			/* shell built-in */
605 		rv = call_builtin(tp, ap);
606 		break;
607 
608 	  case CFUNC:			/* function call */
609 	  {
610 		volatile int old_xflag;
611 		volatile Tflag old_inuse;
612 		const char *volatile old_kshname;
613 
614 		if (!(tp->flag & ISSET)) {
615 			struct tbl *ftp;
616 
617 			if (!tp->u.fpath) {
618 				if (tp->u2.errno_) {
619 					warningf(TRUE,
620 				"%s: can't find function definition file - %s",
621 						cp, strerror(tp->u2.errno_));
622 					rv = 126;
623 				} else {
624 					warningf(TRUE,
625 				"%s: can't find function definition file", cp);
626 					rv = 127;
627 				}
628 				break;
629 			}
630 			if (include(tp->u.fpath, 0, (char **) 0, 0) < 0) {
631 				warningf(TRUE,
632 			    "%s: can't open function definition file %s - %s",
633 					cp, tp->u.fpath, strerror(errno));
634 				rv = 127;
635 				break;
636 			}
637 			if (!(ftp = findfunc(cp, hash(cp), FALSE))
638 			    || !(ftp->flag & ISSET))
639 			{
640 				warningf(TRUE,
641 					"%s: function not defined by %s",
642 					cp, tp->u.fpath);
643 				rv = 127;
644 				break;
645 			}
646 			tp = ftp;
647 		}
648 
649 		/* ksh functions set $0 to function name, POSIX functions leave
650 		 * $0 unchanged.
651 		 */
652 		old_kshname = kshname;
653 		if (tp->flag & FKSH)
654 			kshname = ap[0];
655 		else
656 			ap[0] = (char *) kshname;
657 		e->loc->argv = ap;
658 		for (i = 0; *ap++ != NULL; i++)
659 			;
660 		e->loc->argc = i - 1;
661 		/* ksh-style functions handle getopts sanely,
662 		 * bourne/posix functions are insane...
663 		 */
664 		if (tp->flag & FKSH) {
665 			e->loc->flags |= BF_DOGETOPTS;
666 			e->loc->getopts_state = user_opt;
667 			getopts_reset(1);
668 		}
669 
670 		old_xflag = Flag(FXTRACE);
671 		Flag(FXTRACE) = tp->flag & TRACE ? TRUE : FALSE;
672 
673 		old_inuse = tp->flag & FINUSE;
674 		tp->flag |= FINUSE;
675 
676 		e->type = E_FUNC;
677 		i = ksh_sigsetjmp(e->jbuf, 0);
678 		if (i == 0) {
679 			/* seems odd to pass XERROK here, but at&t ksh does */
680 			exstat = execute(tp->val.t, flags & XERROK);
681 			i = LRETURN;
682 		}
683 		kshname = old_kshname;
684 		Flag(FXTRACE) = old_xflag;
685 		tp->flag = (tp->flag & ~FINUSE) | old_inuse;
686 		/* Were we deleted while executing?  If so, free the execution
687 		 * tree.  todo: Unfortunately, the table entry is never re-used
688 		 * until the lookup table is expanded.
689 		 */
690 		if ((tp->flag & (FDELETE|FINUSE)) == FDELETE) {
691 			if (tp->flag & ALLOC) {
692 				tp->flag &= ~ALLOC;
693 				tfree(tp->val.t, tp->areap);
694 			}
695 			tp->flag = 0;
696 		}
697 		switch (i) {
698 		  case LRETURN:
699 		  case LERROR:
700 			rv = exstat;
701 			break;
702 		  case LINTR:
703 		  case LEXIT:
704 		  case LLEAVE:
705 		  case LSHELL:
706 			quitenv();
707 			unwind(i);
708 			/*NOTREACHED*/
709 		  default:
710 			quitenv();
711 			internal_errorf(1, "CFUNC %d", i);
712 		}
713 		break;
714 	  }
715 
716 	  case CEXEC:		/* executable command */
717 	  case CTALIAS:		/* tracked alias */
718 		if (!(tp->flag&ISSET)) {
719 			/* errno_ will be set if the named command was found
720 			 * but could not be executed (permissions, no execute
721 			 * bit, directory, etc).  Print out a (hopefully)
722 			 * useful error message and set the exit status to 126.
723 			 */
724 			if (tp->u2.errno_) {
725 				warningf(TRUE, "%s: cannot execute - %s", cp,
726 					strerror(tp->u2.errno_));
727 				rv = 126;	/* POSIX */
728 			} else {
729 				warningf(TRUE, "%s: not found", cp);
730 				rv = 127;
731 			}
732 			break;
733 		}
734 
735 #ifdef KSH
736 		/* set $_ to program's full path */
737 		/* setstr() can't fail here */
738 		setstr(typeset("_", LOCAL|EXPORT, 0, INTEGER, 0), tp->val.s,
739 		       KSH_RETURN_ERROR);
740 #endif /* KSH */
741 
742 		if (flags&XEXEC) {
743 			j_exit();
744 			if (!(flags&XBGND) || Flag(FMONITOR)) {
745 				setexecsig(&sigtraps[SIGINT], SS_RESTORE_ORIG);
746 				setexecsig(&sigtraps[SIGQUIT], SS_RESTORE_ORIG);
747 			}
748 		}
749 
750 		/* to fork we set up a TEXEC node and call execute */
751 		texec.type = TEXEC;
752 		texec.left = t;	/* for tprint */
753 		texec.str = tp->val.s;
754 		texec.args = ap;
755 		rv = exchild(&texec, flags, -1);
756 		break;
757 	}
758   Leave:
759 	if (flags & XEXEC) {
760 		exstat = rv;
761 		unwind(LLEAVE);
762 	}
763 	return rv;
764 }
765 
766 static void
767 scriptexec(tp, ap)
768 	register struct op *tp;
769 	register char **ap;
770 {
771 	char *shell;
772 
773 	shell = str_val(global(EXECSHELL_STR));
774 	if (shell && *shell)
775 		shell = search(shell, path, X_OK, (int *) 0);
776 	if (!shell || !*shell)
777 		shell = EXECSHELL;
778 
779 	*tp->args-- = tp->str;
780 #ifdef	SHARPBANG
781 	{
782 		char buf[LINE];
783 		register char *cp;
784 		register int fd, n;
785 
786 		buf[0] = '\0';
787 		if ((fd = open(tp->str, O_RDONLY)) >= 0) {
788 			if ((n = read(fd, buf, LINE - 1)) > 0)
789 				buf[n] = '\0';
790 			(void) close(fd);
791 		}
792 		if ((buf[0] == '#' && buf[1] == '!' && (cp = &buf[2]))
793 # ifdef OS2
794 		    || (strncmp(buf, "extproc", 7) == 0 && isspace(buf[7])
795 			&& (cp = &buf[7]))
796 # endif /* OS2 */
797 		    )
798 		{
799 			while (*cp && (*cp == ' ' || *cp == '\t'))
800 				cp++;
801 			if (*cp && *cp != '\n') {
802 				char *a0 = cp, *a1 = (char *) 0;
803 # ifdef OS2
804 				char *a2 = cp;
805 # endif /* OS2 */
806 
807 				while (*cp && *cp != '\n' && *cp != ' '
808 				       && *cp != '\t')
809 				{
810 # ifdef OS2
811 			/* Allow shell search without prepended path
812 			 * if shell with / in pathname cannot be found.
813 			 * Use / explicitly so \ can be used if explicit
814 			 * needs to be forced.
815 			 */
816 					if (*cp == '/')
817 						a2 = cp + 1;
818 # endif /* OS2 */
819 					cp++;
820 				}
821 				if (*cp && *cp != '\n') {
822 					*cp++ = '\0';
823 					while (*cp
824 					       && (*cp == ' ' || *cp == '\t'))
825 						cp++;
826 					if (*cp && *cp != '\n') {
827 						a1 = cp;
828 						/* all one argument */
829 						while (*cp && *cp != '\n')
830 							cp++;
831 					}
832 				}
833 				if (*cp == '\n') {
834 					*cp = '\0';
835 					if (a1)
836 						*tp->args-- = a1;
837 # ifdef OS2
838 					if (a0 != a2) {
839 						char *tmp_a0 = str_nsave(a0,
840 							strlen(a0) + 5, ATEMP);
841 						if (search_access(tmp_a0, X_OK,
842 								(int *) 0))
843 							a0 = a2;
844 						afree(tmp_a0, ATEMP);
845 					}
846 # endif /* OS2 */
847 					shell = a0;
848 				}
849 			}
850 # ifdef OS2
851 		} else {
852 		        /* Use ksh documented shell default if present
853 			 * else use OS2_SHELL which is assumed to need
854 			 * the /c option and '\' as dir separater.
855 			 */
856 		         char *p = shell;
857 
858 			 shell = str_val(global("EXECSHELL"));
859 			 if (shell && *shell)
860 				 shell = search(shell, path, X_OK, (int *) 0);
861 			 if (!shell || !*shell) {
862 				 shell = p;
863 				 *tp->args-- = "/c";
864 				 for (p = tp->str; *p; p++)
865 					 if (*p == '/')
866 						 *p = '\\';
867 			 }
868 # endif /* OS2 */
869 		}
870 	}
871 #endif	/* SHARPBANG */
872 	*tp->args = shell;
873 
874 	ksh_execve(tp->args[0], tp->args, ap, 0);
875 
876 	/* report both the program that was run and the bogus shell */
877 	errorf("%s: %s: %s", tp->str, shell, strerror(errno));
878 }
879 
880 int
881 shcomexec(wp)
882 	register char **wp;
883 {
884 	register struct tbl *tp;
885 
886 	tp = tsearch(&builtins, *wp, hash(*wp));
887 	if (tp == NULL)
888 		internal_errorf(1, "shcomexec: %s", *wp);
889 	return call_builtin(tp, wp);
890 }
891 
892 /*
893  * Search function tables for a function.  If create set, a table entry
894  * is created if none is found.
895  */
896 struct tbl *
897 findfunc(name, h, create)
898 	const char *name;
899 	unsigned int h;
900 	int create;
901 {
902 	struct block *l;
903 	struct tbl *tp = (struct tbl *) 0;
904 
905 	for (l = e->loc; l; l = l->next) {
906 		tp = tsearch(&l->funs, name, h);
907 		if (tp)
908 			break;
909 		if (!l->next && create) {
910 			tp = tenter(&l->funs, name, h);
911 			tp->flag = DEFINED;
912 			tp->type = CFUNC;
913 			tp->val.t = (struct op *) 0;
914 			break;
915 		}
916 	}
917 	return tp;
918 }
919 
920 /*
921  * define function.  Returns 1 if function is being undefined (t == 0) and
922  * function did not exist, returns 0 otherwise.
923  */
924 int
925 define(name, t)
926 	const char *name;
927 	struct op *t;
928 {
929 	struct tbl *tp;
930 	int was_set = 0;
931 
932 	while (1) {
933 		tp = findfunc(name, hash(name), TRUE);
934 
935 		if (tp->flag & ISSET)
936 			was_set = 1;
937 		/* If this function is currently being executed, we zap this
938 		 * table entry so findfunc() won't see it
939 		 */
940 		if (tp->flag & FINUSE) {
941 			tp->name[0] = '\0';
942 			tp->flag &= ~DEFINED; /* ensure it won't be found */
943 			tp->flag |= FDELETE;
944 		} else
945 			break;
946 	}
947 
948 	if (tp->flag & ALLOC) {
949 		tp->flag &= ~(ISSET|ALLOC);
950 		tfree(tp->val.t, tp->areap);
951 	}
952 
953 	if (t == NULL) {		/* undefine */
954 		tdelete(tp);
955 		return was_set ? 0 : 1;
956 	}
957 
958 	tp->val.t = tcopy(t->left, tp->areap);
959 	tp->flag |= (ISSET|ALLOC);
960 	if (t->u.ksh_func)
961 		tp->flag |= FKSH;
962 
963 	return 0;
964 }
965 
966 /*
967  * add builtin
968  */
969 void
970 builtin(name, func)
971 	const char *name;
972 	int (*func) ARGS((char **));
973 {
974 	register struct tbl *tp;
975 	Tflag flag;
976 
977 	/* see if any flags should be set for this builtin */
978 	for (flag = 0; ; name++) {
979 		if (*name == '=')	/* command does variable assignment */
980 			flag |= KEEPASN;
981 		else if (*name == '*')	/* POSIX special builtin */
982 			flag |= SPEC_BI;
983 		else if (*name == '+')	/* POSIX regular builtin */
984 			flag |= REG_BI;
985 		else
986 			break;
987 	}
988 
989 	tp = tenter(&builtins, name, hash(name));
990 	tp->flag = DEFINED | flag;
991 	tp->type = CSHELL;
992 	tp->val.f = func;
993 }
994 
995 /*
996  * find command
997  * either function, hashed command, or built-in (in that order)
998  */
999 struct tbl *
1000 findcom(name, flags)
1001 	const char *name;
1002 	int	flags;		/* FC_* */
1003 {
1004 	static struct tbl temp;
1005 	unsigned int h = hash(name);
1006 	struct tbl *tp = NULL, *tbi;
1007 	int insert = Flag(FTRACKALL);	/* insert if not found */
1008 	char *fpath;			/* for function autoloading */
1009 	char *npath;
1010 
1011 	if (ksh_strchr_dirsep(name) != NULL) {
1012 		insert = 0;
1013 		/* prevent FPATH search below */
1014 		flags &= ~FC_FUNC;
1015 		goto Search;
1016 	}
1017 	tbi = (flags & FC_BI) ? tsearch(&builtins, name, h) : NULL;
1018 	/* POSIX says special builtins first, then functions, then
1019 	 * POSIX regular builtins, then search path...
1020 	 */
1021 	if ((flags & FC_SPECBI) && tbi && (tbi->flag & SPEC_BI))
1022 		tp = tbi;
1023 	if (!tp && (flags & FC_FUNC)) {
1024 		tp = findfunc(name, h, FALSE);
1025 		if (tp && !(tp->flag & ISSET)) {
1026 			if ((fpath = str_val(global("FPATH"))) == null) {
1027 				tp->u.fpath = (char *) 0;
1028 				tp->u2.errno_ = 0;
1029 			} else
1030 				tp->u.fpath = search(name, fpath, R_OK,
1031 					&tp->u2.errno_);
1032 		}
1033 	}
1034 	if (!tp && (flags & FC_REGBI) && tbi && (tbi->flag & REG_BI))
1035 		tp = tbi;
1036 	/* todo: posix says non-special/non-regular builtins must
1037 	 * be triggered by some user-controllable means like a
1038 	 * special directory in PATH.  Requires modifications to
1039 	 * the search() function.  Tracked aliases should be
1040 	 * modified to allow tracking of builtin commands.
1041 	 * This should be under control of the FPOSIX flag.
1042 	 * If this is changed, also change c_whence...
1043 	 */
1044 	if (!tp && (flags & FC_UNREGBI) && tbi)
1045 		tp = tbi;
1046 	if (!tp && (flags & FC_PATH) && !(flags & FC_DEFPATH)) {
1047 		tp = tsearch(&taliases, name, h);
1048 		if (tp && (tp->flag & ISSET) && eaccess(tp->val.s, X_OK) != 0) {
1049 			if (tp->flag & ALLOC) {
1050 				tp->flag &= ~ALLOC;
1051 				afree(tp->val.s, APERM);
1052 			}
1053 			tp->flag &= ~ISSET;
1054 		}
1055 	}
1056 
1057   Search:
1058 	if ((!tp || (tp->type == CTALIAS && !(tp->flag&ISSET)))
1059 	    && (flags & FC_PATH))
1060 	{
1061 		if (!tp) {
1062 			if (insert && !(flags & FC_DEFPATH)) {
1063 				tp = tenter(&taliases, name, h);
1064 				tp->type = CTALIAS;
1065 			} else {
1066 				tp = &temp;
1067 				tp->type = CEXEC;
1068 			}
1069 			tp->flag = DEFINED;	/* make ~ISSET */
1070 		}
1071 		npath = search(name, flags & FC_DEFPATH ? def_path : path,
1072 				X_OK, &tp->u2.errno_);
1073 		if (npath) {
1074 			tp->val.s = tp == &temp ? npath : str_save(npath, APERM);
1075 			tp->flag |= ISSET|ALLOC;
1076 		} else if ((flags & FC_FUNC)
1077 			   && (fpath = str_val(global("FPATH"))) != null
1078 			   && (npath = search(name, fpath, R_OK,
1079 					      &tp->u2.errno_)) != (char *) 0)
1080 		{
1081 			/* An undocumented feature of at&t ksh is that it
1082 			 * searches FPATH if a command is not found, even
1083 			 * if the command hasn't been set up as an autoloaded
1084 			 * function (ie, no typeset -uf).
1085 			 */
1086 			tp = &temp;
1087 			tp->type = CFUNC;
1088 			tp->flag = DEFINED; /* make ~ISSET */
1089 			tp->u.fpath = npath;
1090 		}
1091 	}
1092 	return tp;
1093 }
1094 
1095 /*
1096  * flush executable commands with relative paths
1097  */
1098 void
1099 flushcom(all)
1100 	int all;		/* just relative or all */
1101 {
1102 	struct tbl *tp;
1103 	struct tstate ts;
1104 
1105 	for (twalk(&ts, &taliases); (tp = tnext(&ts)) != NULL; )
1106 		if ((tp->flag&ISSET) && (all || !ISDIRSEP(tp->val.s[0]))) {
1107 			if (tp->flag&ALLOC) {
1108 				tp->flag &= ~(ALLOC|ISSET);
1109 				afree(tp->val.s, APERM);
1110 			}
1111 			tp->flag &= ~ISSET;
1112 		}
1113 }
1114 
1115 /* Check if path is something we want to find.  Returns -1 for failure. */
1116 int
1117 search_access(path, mode, errnop)
1118 	const char *path;
1119 	int mode;
1120 	int *errnop;		/* set if candidate found, but not suitable */
1121 {
1122 #ifndef OS2
1123 	int ret, err = 0;
1124 	struct stat statb;
1125 
1126 	if (stat(path, &statb) < 0)
1127 		return -1;
1128 	ret = eaccess(path, mode);
1129 	if (ret < 0)
1130 		err = errno; /* File exists, but we can't access it */
1131 	else if (mode == X_OK
1132 		 && (!S_ISREG(statb.st_mode)
1133 		     /* This 'cause access() says root can execute everything */
1134 		     || !(statb.st_mode & (S_IXUSR|S_IXGRP|S_IXOTH))))
1135 	{
1136 		ret = -1;
1137 		err = S_ISDIR(statb.st_mode) ? EISDIR : EACCES;
1138 	}
1139 	if (err && errnop && !*errnop)
1140 		*errnop = err;
1141 	return ret;
1142 #else /* !OS2 */
1143 	/*
1144 	 * NOTE: ASSUMES path can be modified and has enough room at the
1145 	 *       end of the string for a suffix (ie, 4 extra characters).
1146 	 *	 Certain code knows this (eg, eval.c(globit()),
1147 	 *	 exec.c(search())).
1148 	 */
1149 	static char *xsuffixes[] = { ".ksh", ".exe", ".", ".sh", ".cmd",
1150 				     ".com", ".bat", (char *) 0
1151 				   };
1152 	static char *rsuffixes[] = { ".ksh", ".", ".sh", ".cmd", ".bat",
1153 				      (char *) 0
1154 				   };
1155 	int i;
1156 	char *mpath = (char *) path;
1157 	char *tp = mpath + strlen(mpath);
1158 	char *p;
1159 	char **sfx;
1160 
1161 	/* If a suffix has been specified, check if it is one of the
1162 	 * suffixes that indicate the file is executable - if so, change
1163 	 * the access test to R_OK...
1164 	 * This code assumes OS/2 files can have only one suffix...
1165 	 */
1166 	if ((p = strrchr((p = ksh_strrchr_dirsep(mpath)) ? p : mpath, '.'))) {
1167 		if (mode == X_OK)
1168 			mode = R_OK;
1169 		return search_access1(mpath, mode, errnop);
1170 	}
1171 	/* Try appending the various suffixes.  Different suffixes for
1172 	 * read and execute 'cause we don't want to read an executable...
1173 	 */
1174 	sfx = mode == R_OK ? rsuffixes : xsuffixes;
1175 	for (i = 0; sfx[i]; i++) {
1176 		strcpy(tp, p = sfx[i]);
1177 		if (search_access1(mpath, R_OK, errnop) == 0)
1178 			return 0;
1179 		*tp = '\0';
1180 	}
1181 	return -1;
1182 #endif /* !OS2 */
1183 }
1184 
1185 #ifdef OS2
1186 static int
1187 search_access1(path, mode, errnop)
1188 	const char *path;
1189 	int mode;
1190 	int *errnop;		/* set if candidate found, but not suitable */
1191 {
1192 	int ret, err = 0;
1193 	struct stat statb;
1194 
1195 	if (stat(path, &statb) < 0)
1196 		return -1;
1197 	ret = eaccess(path, mode);
1198 	if (ret < 0)
1199 		err = errno; /* File exists, but we can't access it */
1200 	else if (!S_ISREG(statb.st_mode)) {
1201 		ret = -1;
1202 		err = S_ISDIR(statb.st_mode) ? EISDIR : EACCES;
1203 	}
1204 	if (err && errnop && !*errnop)
1205 		*errnop = err;
1206 	return ret;
1207 }
1208 #endif /* OS2 */
1209 
1210 /*
1211  * search for command with PATH
1212  */
1213 char *
1214 search(name, path, mode, errnop)
1215 	const char *name;
1216 	const char *path;
1217 	int mode;		/* R_OK or X_OK */
1218 	int *errnop;		/* set if candidate found, but not suitable */
1219 {
1220 	const char *sp, *p;
1221 	char *xp;
1222 	XString xs;
1223 	int namelen;
1224 
1225 	if (errnop)
1226 		*errnop = 0;
1227 #ifdef OS2
1228 	/* Xinit() allocates 8 additional bytes, so appended suffixes won't
1229 	 * overflow the memory.
1230 	 */
1231 	namelen = strlen(name) + 1;
1232 	Xinit(xs, xp, namelen, ATEMP);
1233 	memcpy(Xstring(xs, xp), name, namelen);
1234 
1235  	if (ksh_strchr_dirsep(name)) {
1236 		if (search_access(Xstring(xs, xp), mode, errnop) >= 0)
1237 			return Xstring(xs, xp); /* not Xclose() - see above */
1238 		Xfree(xs, xp);
1239 		return NULL;
1240 	}
1241 
1242 	/* Look in current context always. (os2 style) */
1243 	if (search_access(Xstring(xs, xp), mode, errnop) == 0)
1244 		return Xstring(xs, xp); /* not Xclose() - xp may be wrong */
1245 #else /* OS2 */
1246 	if (ksh_strchr_dirsep(name)) {
1247 		if (search_access(name, mode, errnop) == 0)
1248 			return (char *) name;
1249 		return NULL;
1250 	}
1251 
1252 	namelen = strlen(name) + 1;
1253 	Xinit(xs, xp, 128, ATEMP);
1254 #endif /* OS2 */
1255 
1256 	sp = path;
1257 	while (sp != NULL) {
1258 		xp = Xstring(xs, xp);
1259 		if (!(p = strchr(sp, PATHSEP)))
1260 			p = sp + strlen(sp);
1261 		if (p != sp) {
1262 			XcheckN(xs, xp, p - sp);
1263 			memcpy(xp, sp, p - sp);
1264 			xp += p - sp;
1265 			*xp++ = DIRSEP;
1266 		}
1267 		sp = p;
1268 		XcheckN(xs, xp, namelen);
1269 		memcpy(xp, name, namelen);
1270  		if (search_access(Xstring(xs, xp), mode, errnop) == 0)
1271 #ifdef OS2
1272  			return Xstring(xs, xp); /* Not Xclose() - see above */
1273 #else /* OS2 */
1274 			return Xclose(xs, xp + namelen);
1275 #endif /* OS2 */
1276 		if (*sp++ == '\0')
1277 			sp = NULL;
1278 	}
1279 	Xfree(xs, xp);
1280 	return NULL;
1281 }
1282 
1283 static int
1284 call_builtin(tp, wp)
1285 	struct tbl *tp;
1286 	char **wp;
1287 {
1288 	int rv;
1289 
1290 	builtin_argv0 = wp[0];
1291 	builtin_flag = tp->flag;
1292 	shf_reopen(1, SHF_WR, shl_stdout);
1293 	shl_stdout_ok = 1;
1294 	ksh_getopt_reset(&builtin_opt, GF_ERROR);
1295 	rv = (*tp->val.f)(wp);
1296 	shf_flush(shl_stdout);
1297 	shl_stdout_ok = 0;
1298 	builtin_flag = 0;
1299 	builtin_argv0 = (char *) 0;
1300 	return rv;
1301 }
1302 
1303 /*
1304  * set up redirection, saving old fd's in e->savefd
1305  */
1306 static int
1307 iosetup(iop, tp)
1308 	register struct ioword *iop;
1309 	struct tbl *tp;
1310 {
1311 	register int u = -1;
1312 	char *cp = iop->name;
1313 	int iotype = iop->flag & IOTYPE;
1314 	int do_open = 1, do_close = 0, UNINITIALIZED(flags);
1315 	struct ioword iotmp;
1316 	struct stat statb;
1317 
1318 	if (iotype != IOHERE)
1319 		cp = evalonestr(cp, DOTILDE|(Flag(FTALKING_I) ? DOGLOB : 0));
1320 
1321 	/* Used for tracing and error messages to print expanded cp */
1322 	iotmp = *iop;
1323 	iotmp.name = (iotype == IOHERE) ? (char *) 0 : cp;
1324 	iotmp.flag |= IONAMEXP;
1325 
1326 	if (Flag(FXTRACE))
1327 		shellf("%s%s\n",
1328 			PS4_SUBSTITUTE(str_val(global("PS4"))),
1329 			snptreef((char *) 0, 32, "%R", &iotmp));
1330 
1331 	switch (iotype) {
1332 	  case IOREAD:
1333 		flags = O_RDONLY;
1334 		break;
1335 
1336 	  case IOCAT:
1337 		flags = O_WRONLY | O_APPEND | O_CREAT;
1338 		break;
1339 
1340 	  case IOWRITE:
1341 		flags = O_WRONLY | O_CREAT | O_TRUNC;
1342 		/* The stat() is here to allow redirections to
1343 		 * things like /dev/null without error.
1344 		 */
1345 		if (Flag(FNOCLOBBER) && !(iop->flag & IOCLOB)
1346 		    && (stat(cp, &statb) < 0 || S_ISREG(statb.st_mode)))
1347 			flags |= O_EXCL;
1348 		break;
1349 
1350 	  case IORDWR:
1351 		flags = O_RDWR | O_CREAT;
1352 		break;
1353 
1354 	  case IOHERE:
1355 		do_open = 0;
1356 		/* herein() returns -2 if error has been printed */
1357 		u = herein(iop->heredoc, iop->flag & IOEVAL);
1358 		/* cp may have wrong name */
1359 		break;
1360 
1361 	  case IODUP:
1362 	  {
1363 		const char *emsg;
1364 
1365 		do_open = 0;
1366 		if (*cp == '-' && !cp[1]) {
1367 			u = 1009;	 /* prevent error return below */
1368 			do_close = 1;
1369 		} else if ((u = check_fd(cp,
1370 				X_OK | ((iop->flag & IORDUP) ? R_OK : W_OK),
1371 				&emsg)) < 0)
1372 		{
1373 			warningf(TRUE, "%s: %s",
1374 				snptreef((char *) 0, 32, "%R", &iotmp), emsg);
1375 			return -1;
1376 		}
1377 		break;
1378 	  }
1379 	}
1380 	if (do_open) {
1381 		if (Flag(FRESTRICTED) && (flags & O_CREAT)) {
1382 			warningf(TRUE, "%s: restricted", cp);
1383 			return -1;
1384 		}
1385 		u = open(cp, flags, 0666);
1386 #ifdef OS2
1387 		if (u < 0 && strcmp(cp, "/dev/null") == 0)
1388 			u = open("nul", flags, 0666);
1389 #endif /* OS2 */
1390 	}
1391 	if (u < 0) {
1392 		/* herein() may already have printed message */
1393 		if (u == -1)
1394 			warningf(TRUE, "cannot %s %s: %s",
1395 			       iotype == IODUP ? "dup"
1396 				: (iotype == IOREAD || iotype == IOHERE) ?
1397 				    "open" : "create", cp, strerror(errno));
1398 		return -1;
1399 	}
1400 	/* Do not save if it has already been redirected (i.e. "cat >x >y"). */
1401 	if (e->savefd[iop->unit] == 0)
1402 		/* c_exec() assumes e->savefd[fd] set for any redirections.
1403 		 * Ask savefd() not to close iop->unit - allows error messages
1404 		 * to be seen if iop->unit is 2; also means we can't lose
1405 		 * the fd (eg, both dup2 below and dup2 in restfd() failing).
1406 		 */
1407 		e->savefd[iop->unit] = savefd(iop->unit, 1);
1408 
1409 	if (do_close)
1410 		close(iop->unit);
1411 	else if (u != iop->unit) {
1412 		if (ksh_dup2(u, iop->unit, TRUE) < 0) {
1413 			warningf(TRUE,
1414 				"could not finish (dup) redirection %s: %s",
1415 				snptreef((char *) 0, 32, "%R", &iotmp),
1416 				strerror(errno));
1417 			if (iotype != IODUP)
1418 				close(u);
1419 			return -1;
1420 		}
1421 		if (iotype != IODUP)
1422 			close(u);
1423 #ifdef KSH
1424 		/* Touching any co-process fd in an empty exec
1425 		 * causes the shell to close its copies
1426 		 */
1427 		else if (tp && tp->type == CSHELL && tp->val.f == c_exec) {
1428 			if (iop->flag & IORDUP)	/* possible exec <&p */
1429 				coproc_read_close(u);
1430 			else			/* possible exec >&p */
1431 				coproc_write_close(u);
1432 		}
1433 #endif /* KSH */
1434 	}
1435 	if (u == 2) /* Clear any write errors */
1436 		shf_reopen(2, SHF_WR, shl_out);
1437 	return 0;
1438 }
1439 
1440 /*
1441  * open here document temp file.
1442  * if unquoted here, expand here temp file into second temp file.
1443  */
1444 static int
1445 herein(content, sub)
1446 	const char *content;
1447 	int sub;
1448 {
1449 	volatile int fd = -1;
1450 	struct source *s, *volatile osource;
1451 	struct shf *volatile shf;
1452 	struct temp *h;
1453 	int i;
1454 
1455 	/* ksh -c 'cat << EOF' can cause this... */
1456 	if (content == (char *) 0) {
1457 		warningf(TRUE, "here document missing");
1458 		return -2; /* special to iosetup(): don't print error */
1459 	}
1460 
1461 	/* Create temp file to hold content (done before newenv so temp
1462 	 * doesn't get removed too soon).
1463 	 */
1464 	h = maketemp(ATEMP, TT_HEREDOC_EXP, &e->temps);
1465 	if (!(shf = h->shf) || (fd = open(h->name, O_RDONLY, 0)) < 0) {
1466 		warningf(TRUE, "can't %s temporary file %s: %s",
1467 			!shf ? "create" : "open",
1468 			h->name, strerror(errno));
1469 		if (shf)
1470 			shf_close(shf);
1471 		return -2 /* special to iosetup(): don't print error */;
1472 	}
1473 
1474 	osource = source;
1475 	newenv(E_ERRH);
1476 	i = ksh_sigsetjmp(e->jbuf, 0);
1477 	if (i) {
1478 		source = osource;
1479 		quitenv();
1480 		shf_close(shf);	/* after quitenv */
1481 		close(fd);
1482 		return -2; /* special to iosetup(): don't print error */
1483 	}
1484 	if (sub) {
1485 		/* Do substitutions on the content of heredoc */
1486 		s = pushs(SSTRING, ATEMP);
1487 		s->start = s->str = content;
1488 		source = s;
1489 		if (yylex(ONEWORD) != LWORD)
1490 			internal_errorf(1, "herein: yylex");
1491 		source = osource;
1492 		shf_puts(evalstr(yylval.cp, 0), shf);
1493 	} else
1494 		shf_puts(content, shf);
1495 
1496 	quitenv();
1497 
1498 	if (shf_close(shf) == EOF) {
1499 		close(fd);
1500 		warningf(TRUE, "error writing %s: %s", h->name,
1501 			strerror(errno));
1502 		return -2; /* special to iosetup(): don't print error */
1503 	}
1504 
1505 	return fd;
1506 }
1507 
1508 #ifdef KSH
1509 /*
1510  *	ksh special - the select command processing section
1511  *	print the args in column form - assuming that we can
1512  */
1513 static char *
1514 do_selectargs(ap, print_menu)
1515 	register char **ap;
1516 	bool_t print_menu;
1517 {
1518 	static const char *const read_args[] = {
1519 					"read", "-r", "REPLY", (char *) 0
1520 				    };
1521 	char *s;
1522 	int i, argct;
1523 
1524 	for (argct = 0; ap[argct]; argct++)
1525 		;
1526 	while (1) {
1527 		/* Menu is printed if
1528 		 *	- this is the first time around the select loop
1529 		 *	- the user enters a blank line
1530 		 *	- the REPLY parameter is empty
1531 		 */
1532 		if (print_menu || !*str_val(global("REPLY")))
1533 			pr_menu(ap);
1534 		shellf("%s", str_val(global("PS3")));
1535 		if (call_builtin(findcom("read", FC_BI), (char **) read_args))
1536 			return (char *) 0;
1537 		s = str_val(global("REPLY"));
1538 		if (*s) {
1539 			i = atoi(s);
1540 			return (i >= 1 && i <= argct) ? ap[i - 1] : null;
1541 		}
1542 		print_menu = 1;
1543 	}
1544 }
1545 
1546 struct select_menu_info {
1547 	char	*const *args;
1548 	int	arg_width;
1549 	int	num_width;
1550 } info;
1551 
1552 static char *select_fmt_entry ARGS((void *arg, int i, char *buf, int buflen));
1553 
1554 /* format a single select menu item */
1555 static char *
1556 select_fmt_entry(arg, i, buf, buflen)
1557 	void *arg;
1558 	int i;
1559 	char *buf;
1560 	int buflen;
1561 {
1562 	struct select_menu_info *smi = (struct select_menu_info *) arg;
1563 
1564 	shf_snprintf(buf, buflen, "%*d) %s",
1565 		smi->num_width, i + 1, smi->args[i]);
1566 	return buf;
1567 }
1568 
1569 /*
1570  *	print a select style menu
1571  */
1572 int
1573 pr_menu(ap)
1574 	char *const *ap;
1575 {
1576 	struct select_menu_info smi;
1577 	char *const *pp;
1578 	int nwidth, dwidth;
1579 	int i, n;
1580 
1581 	/* Width/column calculations were done once and saved, but this
1582 	 * means select can't be used recursively so we re-calculate each
1583 	 * time (could save in a structure that is returned, but its probably
1584 	 * not worth the bother).
1585 	 */
1586 
1587 	/*
1588 	 * get dimensions of the list
1589 	 */
1590 	for (n = 0, nwidth = 0, pp = ap; *pp; n++, pp++) {
1591 		i = strlen(*pp);
1592 		nwidth = (i > nwidth) ? i : nwidth;
1593 	}
1594 	/*
1595 	 * we will print an index of the form
1596 	 *	%d)
1597 	 * in front of each entry
1598 	 * get the max width of this
1599 	 */
1600 	for (i = n, dwidth = 1; i >= 10; i /= 10)
1601 		dwidth++;
1602 
1603 	smi.args = ap;
1604 	smi.arg_width = nwidth;
1605 	smi.num_width = dwidth;
1606 	print_columns(shl_out, n, select_fmt_entry, (void *) &smi,
1607 		dwidth + nwidth + 2, 1);
1608 
1609 	return n;
1610 }
1611 
1612 /* XXX: horrible kludge to fit within the framework */
1613 
1614 static char *plain_fmt_entry ARGS((void *arg, int i, char *buf, int buflen));
1615 
1616 static char *
1617 plain_fmt_entry(arg, i, buf, buflen)
1618 	void *arg;
1619 	int i;
1620 	char *buf;
1621 	int buflen;
1622 {
1623 	shf_snprintf(buf, buflen, "%s", ((char *const *)arg)[i]);
1624 	return buf;
1625 }
1626 
1627 int
1628 pr_list(ap)
1629 	char *const *ap;
1630 {
1631 	char *const *pp;
1632 	int nwidth;
1633 	int i, n;
1634 
1635 	for (n = 0, nwidth = 0, pp = ap; *pp; n++, pp++) {
1636 		i = strlen(*pp);
1637 		nwidth = (i > nwidth) ? i : nwidth;
1638 	}
1639 	print_columns(shl_out, n, plain_fmt_entry, (void *) ap, nwidth + 1, 0);
1640 
1641 	return n;
1642 }
1643 #endif /* KSH */
1644 #ifdef KSH
1645 
1646 /*
1647  *	[[ ... ]] evaluation routines
1648  */
1649 
1650 extern const char *const dbtest_tokens[];
1651 extern const char db_close[];
1652 
1653 /* Test if the current token is a whatever.  Accepts the current token if
1654  * it is.  Returns 0 if it is not, non-zero if it is (in the case of
1655  * TM_UNOP and TM_BINOP, the returned value is a Test_op).
1656  */
1657 static int
1658 dbteste_isa(te, meta)
1659 	Test_env *te;
1660 	Test_meta meta;
1661 {
1662 	int ret = 0;
1663 	int uqword;
1664 	char *p;
1665 
1666 	if (!*te->pos.wp)
1667 		return meta == TM_END;
1668 
1669 	/* unquoted word? */
1670 	for (p = *te->pos.wp; *p == CHAR; p += 2)
1671 		;
1672 	uqword = *p == EOS;
1673 
1674 	if (meta == TM_UNOP || meta == TM_BINOP) {
1675 		if (uqword) {
1676 			char buf[8];	/* longer than the longest operator */
1677 			char *q = buf;
1678 			for (p = *te->pos.wp; *p == CHAR
1679 					      && q < &buf[sizeof(buf) - 1];
1680 					      p += 2)
1681 				*q++ = p[1];
1682 			*q = '\0';
1683 			ret = (int) test_isop(te, meta, buf);
1684 		}
1685 	} else if (meta == TM_END)
1686 		ret = 0;
1687 	else
1688 		ret = uqword
1689 			&& strcmp(*te->pos.wp, dbtest_tokens[(int) meta]) == 0;
1690 
1691 	/* Accept the token? */
1692 	if (ret)
1693 		te->pos.wp++;
1694 
1695 	return ret;
1696 }
1697 
1698 static const char *
1699 dbteste_getopnd(te, op, do_eval)
1700 	Test_env *te;
1701 	Test_op op;
1702 	int do_eval;
1703 {
1704 	char *s = *te->pos.wp;
1705 
1706 	if (!s)
1707 		return (char *) 0;
1708 
1709 	te->pos.wp++;
1710 
1711 	if (!do_eval)
1712 		return null;
1713 
1714 	if (op == TO_STEQL || op == TO_STNEQ)
1715 		s = evalstr(s, DOTILDE | DOPAT);
1716 	else
1717 		s = evalstr(s, DOTILDE);
1718 
1719 	return s;
1720 }
1721 
1722 static int
1723 dbteste_eval(te, op, opnd1, opnd2, do_eval)
1724 	Test_env *te;
1725 	Test_op op;
1726 	const char *opnd1;
1727 	const char *opnd2;
1728 	int do_eval;
1729 {
1730 	return test_eval(te, op, opnd1, opnd2, do_eval);
1731 }
1732 
1733 static void
1734 dbteste_error(te, offset, msg)
1735 	Test_env *te;
1736 	int offset;
1737 	const char *msg;
1738 {
1739 	te->flags |= TEF_ERROR;
1740 	internal_errorf(0, "dbteste_error: %s (offset %d)", msg, offset);
1741 }
1742 #endif /* KSH */
1743