xref: /netbsd-src/bin/ksh/var.c (revision e5548b402ae4c44fb816de42c7bba9581ce23ef5) 
1 /*	$NetBSD: var.c,v 1.12 2005/06/26 19:09:00 christos Exp $	*/
2 
3 #include <sys/cdefs.h>
4 
5 #ifndef lint
6 __RCSID("$NetBSD: var.c,v 1.12 2005/06/26 19:09:00 christos Exp $");
7 #endif
8 
9 
10 #include "sh.h"
11 #include "ksh_time.h"
12 #include "ksh_limval.h"
13 #include "ksh_stat.h"
14 #include <ctype.h>
15 
16 /*
17  * Variables
18  *
19  * WARNING: unreadable code, needs a rewrite
20  *
21  * if (flag&INTEGER), val.i contains integer value, and type contains base.
22  * otherwise, (val.s + type) contains string value.
23  * if (flag&EXPORT), val.s contains "name=value" for E-Z exporting.
24  */
25 static	struct tbl vtemp;
26 static	struct table specials;
27 static char	*formatstr	ARGS((struct tbl *vp, const char *s));
28 static void	export		ARGS((struct tbl *vp, const char *val));
29 static int	special		ARGS((const char *name));
30 static void	unspecial	ARGS((const char *name));
31 static void	getspec		ARGS((struct tbl *vp));
32 static void	setspec		ARGS((struct tbl *vp));
33 static void	unsetspec	ARGS((struct tbl *vp));
34 static struct tbl *arraysearch  ARGS((struct tbl *, int));
35 
36 /*
37  * create a new block for function calls and simple commands
38  * assume caller has allocated and set up e->loc
39  */
40 void
41 newblock()
42 {
43 	register struct block *l;
44 	static char *const empty[] = {null};
45 
46 	l = (struct block *) alloc(sizeof(struct block), ATEMP);
47 	l->flags = 0;
48 	ainit(&l->area); /* todo: could use e->area (l->area => l->areap) */
49 	if (!e->loc) {
50 		l->argc = 0;
51 		l->argv = (char **) __UNCONST(empty);
52 	} else {
53 		l->argc = e->loc->argc;
54 		l->argv = e->loc->argv;
55 	}
56 	l->exit = l->error = NULL;
57 	tinit(&l->vars, &l->area, 0);
58 	tinit(&l->funs, &l->area, 0);
59 	l->next = e->loc;
60 	e->loc = l;
61 }
62 
63 /*
64  * pop a block handling special variables
65  */
66 void
67 popblock()
68 {
69 	register struct block *l = e->loc;
70 	register struct tbl *vp, **vpp = l->vars.tbls, *vq;
71 	register int i;
72 
73 	e->loc = l->next;	/* pop block */
74 	for (i = l->vars.size; --i >= 0; ) {
75 		if ((vp = *vpp++) != NULL && (vp->flag&SPECIAL)) {
76 			if ((vq = global(vp->name))->flag & ISSET)
77 				setspec(vq);
78 			else
79 				unsetspec(vq);
80 		}
81 	}
82 	if (l->flags & BF_DOGETOPTS)
83 		user_opt = l->getopts_state;
84 	afreeall(&l->area);
85 	afree(l, ATEMP);
86 }
87 
88 /* called by main() to initialize variable data structures */
89 void
90 initvar()
91 {
92 	static const struct {
93 		const char *name;
94 		int v;
95 	} names[] = {
96 			{ "COLUMNS",		V_COLUMNS },
97 			{ "IFS",		V_IFS },
98 			{ "OPTIND",		V_OPTIND },
99 			{ "PATH",		V_PATH },
100 			{ "POSIXLY_CORRECT",	V_POSIXLY_CORRECT },
101 			{ "TMPDIR",		V_TMPDIR },
102 #ifdef HISTORY
103 			{ "HISTFILE",		V_HISTFILE },
104 			{ "HISTSIZE",		V_HISTSIZE },
105 #endif /* HISTORY */
106 #ifdef EDIT
107 			{ "EDITOR",		V_EDITOR },
108 			{ "VISUAL",		V_VISUAL },
109 #endif /* EDIT */
110 #ifdef KSH
111 			{ "MAIL",		V_MAIL },
112 			{ "MAILCHECK",		V_MAILCHECK },
113 			{ "MAILPATH",		V_MAILPATH },
114 			{ "RANDOM",		V_RANDOM },
115 			{ "SECONDS",		V_SECONDS },
116 			{ "TMOUT",		V_TMOUT },
117 #endif /* KSH */
118 			{ "LINENO",		V_LINENO },
119 			{ (char *) 0,	0 }
120 		};
121 	int i;
122 	struct tbl *tp;
123 
124 	tinit(&specials, APERM, 32); /* must be 2^n (currently 17 specials) */
125 	for (i = 0; names[i].name; i++) {
126 		tp = tenter(&specials, names[i].name, hash(names[i].name));
127 		tp->flag = DEFINED|ISSET;
128 		tp->type = names[i].v;
129 	}
130 }
131 
132 /* Used to calculate an array index for global()/local().  Sets *arrayp to
133  * non-zero if this is an array, sets *valp to the array index, returns
134  * the basename of the array.
135  */
136 const char *array_index_calc(const char *n, bool_t *arrayp, int *valp);
137 
138 const char *
139 array_index_calc(n, arrayp, valp)
140 	const char *n;
141 	bool_t *arrayp;
142 	int *valp;
143 {
144 	const char *p;
145 	int len;
146 
147 	*arrayp = FALSE;
148 	p = skip_varname(n, FALSE);
149 	if (p != n && *p == '[' && (len = array_ref_len(p))) {
150 		char *sub, *tmp;
151 		long rval;
152 
153 		/* Calculate the value of the subscript */
154 		*arrayp = TRUE;
155 		tmp = str_nsave(p+1, len-2, ATEMP);
156 		sub = substitute(tmp, 0);
157 		afree(tmp, ATEMP);
158 		n = str_nsave(n, p - n, ATEMP);
159 		evaluate(sub, &rval, KSH_UNWIND_ERROR);
160 		if (rval < 0 || rval > ARRAYMAX)
161 			errorf("%s: subscript out of range", n);
162 		*valp = rval;
163 		afree(sub, ATEMP);
164 	}
165 	return n;
166 }
167 
168 /*
169  * Search for variable, if not found create globally.
170  */
171 struct tbl *
172 global(n)
173 	register const char *n;
174 {
175 	register struct block *l = e->loc;
176 	register struct tbl *vp;
177 	register int c;
178 	unsigned h;
179 	bool_t	 array;
180 	int	 val;
181 
182 	/* Check to see if this is an array */
183 	n = array_index_calc(n, &array, &val);
184 	h = hash(n);
185 	c = n[0];
186 	if (!letter(c)) {
187 		if (array)
188 			errorf("bad substitution");
189 		vp = &vtemp;
190 		vp->flag = DEFINED;
191 		vp->type = 0;
192 		vp->areap = ATEMP;
193 		*vp->name = c;
194 		if (digit(c)) {
195 			for (c = 0; digit(*n); n++)
196 				c = c*10 + *n-'0';
197 			if (c <= l->argc)
198 				/* setstr can't fail here */
199 				setstr(vp, l->argv[c], KSH_RETURN_ERROR);
200 			vp->flag |= RDONLY;
201 			return vp;
202 		}
203 		vp->flag |= RDONLY;
204 		if (n[1] != '\0')
205 			return vp;
206 		vp->flag |= ISSET|INTEGER;
207 		switch (c) {
208 		  case '$':
209 			vp->val.i = kshpid;
210 			break;
211 		  case '!':
212 			/* If no job, expand to nothing */
213 			if ((vp->val.i = j_async()) == 0)
214 				vp->flag &= ~(ISSET|INTEGER);
215 			break;
216 		  case '?':
217 			vp->val.i = exstat;
218 			break;
219 		  case '#':
220 			vp->val.i = l->argc;
221 			break;
222 		  case '-':
223 			vp->flag &= ~INTEGER;
224 			vp->val.s = getoptions();
225 			break;
226 		  default:
227 			vp->flag &= ~(ISSET|INTEGER);
228 		}
229 		return vp;
230 	}
231 	for (l = e->loc; ; l = l->next) {
232 		vp = tsearch(&l->vars, n, h);
233 		if (vp != NULL) {
234 			if (array)
235 				return arraysearch(vp, val);
236 			else
237 				return vp;
238 		}
239 		if (l->next == NULL)
240 			break;
241 	}
242 	vp = tenter(&l->vars, n, h);
243 	if (array)
244 		vp = arraysearch(vp, val);
245 	vp->flag |= DEFINED;
246 	if (special(n))
247 		vp->flag |= SPECIAL;
248 	return vp;
249 }
250 
251 /*
252  * Search for local variable, if not found create locally.
253  */
254 struct tbl *
255 local(n, copy)
256 	register const char *n;
257 	bool_t copy;
258 {
259 	register struct block *l = e->loc;
260 	register struct tbl *vp;
261 	unsigned h;
262 	bool_t	 array;
263 	int	 val;
264 
265 	/* Check to see if this is an array */
266 	n = array_index_calc(n, &array, &val);
267 	h = hash(n);
268 	if (!letter(*n)) {
269 		vp = &vtemp;
270 		vp->flag = DEFINED|RDONLY;
271 		vp->type = 0;
272 		vp->areap = ATEMP;
273 		return vp;
274 	}
275 	vp = tenter(&l->vars, n, h);
276 	if (copy && !(vp->flag & DEFINED)) {
277 		struct block *ll = l;
278 		struct tbl *vq = (struct tbl *) 0;
279 
280 		while ((ll = ll->next) && !(vq = tsearch(&ll->vars, n, h)))
281 			;
282 		if (vq) {
283 			vp->flag |= vq->flag & (EXPORT|INTEGER|RDONLY
284 						|LJUST|RJUST|ZEROFIL
285 						|LCASEV|UCASEV_AL|INT_U|INT_L);
286 			if (vq->flag & INTEGER)
287 				vp->type = vq->type;
288 			vp->u2.field = vq->u2.field;
289 		}
290 	}
291 	if (array)
292 		vp = arraysearch(vp, val);
293 	vp->flag |= DEFINED;
294 	if (special(n))
295 		vp->flag |= SPECIAL;
296 	return vp;
297 }
298 
299 /* get variable string value */
300 char *
301 str_val(vp)
302 	register struct tbl *vp;
303 {
304 	char *s;
305 
306 	if ((vp->flag&SPECIAL))
307 		getspec(vp);
308 	if (!(vp->flag&ISSET))
309 		s = null;		/* special to dollar() */
310 	else if (!(vp->flag&INTEGER))	/* string source */
311 		s = vp->val.s + vp->type;
312 	else {				/* integer source */
313 		/* worst case number length is when base=2, so use BITS(long) */
314 			     /* minus base #     number    null */
315 		static char strbuf[1 + 2 + 1 + BITS(long) + 1];
316 		const char *digits = (vp->flag & UCASEV_AL) ?
317 				  "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
318 				: "0123456789abcdefghijklmnopqrstuvwxyz";
319 		register unsigned long n;
320 		register int base;
321 
322 		s = strbuf + sizeof(strbuf);
323 		if (vp->flag & INT_U)
324 			n = (unsigned long) vp->val.i;
325 		else
326 			n = (vp->val.i < 0) ? -vp->val.i : vp->val.i;
327 		base = (vp->type == 0) ? 10 : vp->type;
328 
329 		*--s = '\0';
330 		do {
331 			*--s = digits[n % base];
332 			n /= base;
333 		} while (n != 0);
334 		if (base != 10) {
335 			*--s = '#';
336 			*--s = digits[base % 10];
337 			if (base >= 10)
338 				*--s = digits[base / 10];
339 		}
340 		if (!(vp->flag & INT_U) && vp->val.i < 0)
341 			*--s = '-';
342 		if (vp->flag & (RJUST|LJUST)) /* case already dealt with */
343 			s = formatstr(vp, s);
344 	}
345 	return s;
346 }
347 
348 /* get variable integer value, with error checking */
349 long
350 intval(vp)
351 	register struct tbl *vp;
352 {
353 	long num;
354 	int base;
355 
356 	base = getint(vp, &num);
357 	if (base == -1)
358 		/* XXX check calls - is error here ok by POSIX? */
359 		errorf("%s: bad number", str_val(vp));
360 	return num;
361 }
362 
363 /* set variable to string value */
364 int
365 setstr(vq, s, error_ok)
366 	register struct tbl *vq;
367 	const char *s;
368 	int error_ok;
369 {
370 	int no_ro_check = error_ok & 0x4;
371 	error_ok &= ~0x4;
372 	if ((vq->flag & RDONLY) && !no_ro_check) {
373 		warningf(TRUE, "%s: is read only", vq->name);
374 		if (!error_ok)
375 			errorf(null);
376 		return 0;
377 	}
378 	if (!(vq->flag&INTEGER)) { /* string dest */
379 		if ((vq->flag&ALLOC)) {
380 			/* debugging */
381 			if (s >= vq->val.s
382 			    && s <= vq->val.s + strlen(vq->val.s))
383 				internal_errorf(TRUE,
384 				    "setstr: %s=%s: assigning to self",
385 				    vq->name, s);
386 			afree((void*)vq->val.s, vq->areap);
387 		}
388 		vq->flag &= ~(ISSET|ALLOC);
389 		vq->type = 0;
390 		if (s && (vq->flag & (UCASEV_AL|LCASEV|LJUST|RJUST)))
391 			s = formatstr(vq, s);
392 		if ((vq->flag&EXPORT))
393 			export(vq, s);
394 		else {
395 			vq->val.s = str_save(s, vq->areap);
396 			vq->flag |= ALLOC;
397 		}
398 	} else			/* integer dest */
399 		if (!v_evaluate(vq, s, error_ok))
400 			return 0;
401 	vq->flag |= ISSET;
402 	if ((vq->flag&SPECIAL))
403 		setspec(vq);
404 	return 1;
405 }
406 
407 /* set variable to integer */
408 void
409 setint(vq, n)
410 	register struct tbl *vq;
411 	long n;
412 {
413 	if (!(vq->flag&INTEGER)) {
414 		register struct tbl *vp = &vtemp;
415 		vp->flag = (ISSET|INTEGER);
416 		vp->type = 0;
417 		vp->areap = ATEMP;
418 		vp->val.i = n;
419 		/* setstr can't fail here */
420 		setstr(vq, str_val(vp), KSH_RETURN_ERROR);
421 	} else
422 		vq->val.i = n;
423 	vq->flag |= ISSET;
424 	if ((vq->flag&SPECIAL))
425 		setspec(vq);
426 }
427 
428 int
429 getint(vp, nump)
430 	struct tbl *vp;
431 	long *nump;
432 {
433 	register char *s;
434 	register int c;
435 	int base, neg;
436 	int have_base = 0;
437 	long num;
438 
439 	if (vp->flag&SPECIAL)
440 		getspec(vp);
441 	/* XXX is it possible for ISSET to be set and val.s to be 0? */
442 	if (!(vp->flag&ISSET) || (!(vp->flag&INTEGER) && vp->val.s == NULL))
443 		return -1;
444 	if (vp->flag&INTEGER) {
445 		*nump = vp->val.i;
446 		return vp->type;
447 	}
448 	s = vp->val.s + vp->type;
449 	if (s == NULL)	/* redundant given initial test */
450 		s = null;
451 	base = 10;
452 	num = 0;
453 	neg = 0;
454 	for (c = (unsigned char)*s++; c ; c = (unsigned char)*s++) {
455 		if (c == '-') {
456 			neg++;
457 		} else if (c == '#') {
458 			base = (int) num;
459 			if (have_base || base < 2 || base > 36)
460 				return -1;
461 			num = 0;
462 			have_base = 1;
463 		} else if (letnum(c)) {
464 			if (isdigit(c))
465 				c -= '0';
466 			else if (islower(c))
467 				c -= 'a' - 10; /* todo: assumes ascii */
468 			else if (isupper(c))
469 				c -= 'A' - 10; /* todo: assumes ascii */
470 			else
471 				c = -1; /* _: force error */
472 			if (c < 0 || c >= base)
473 				return -1;
474 			num = num * base + c;
475 		} else
476 			return -1;
477 	}
478 	if (neg)
479 		num = -num;
480 	*nump = num;
481 	return base;
482 }
483 
484 /* convert variable vq to integer variable, setting its value from vp
485  * (vq and vp may be the same)
486  */
487 struct tbl *
488 setint_v(vq, vp)
489 	register struct tbl *vq, *vp;
490 {
491 	int base;
492 	long num;
493 
494 	if ((base = getint(vp, &num)) == -1)
495 		return NULL;
496 	if (!(vq->flag & INTEGER) && (vq->flag & ALLOC)) {
497 		vq->flag &= ~ALLOC;
498 		afree(vq->val.s, vq->areap);
499 	}
500 	vq->val.i = num;
501 	if (vq->type == 0) /* default base */
502 		vq->type = base;
503 	vq->flag |= ISSET|INTEGER;
504 	if (vq->flag&SPECIAL)
505 		setspec(vq);
506 	return vq;
507 }
508 
509 static char *
510 formatstr(vp, s)
511 	struct tbl *vp;
512 	const char *s;
513 {
514 	int olen, nlen;
515 	char *p, *q;
516 
517 	olen = strlen(s);
518 
519 	if (vp->flag & (RJUST|LJUST)) {
520 		if (!vp->u2.field)	/* default field width */
521 			vp->u2.field = olen;
522 		nlen = vp->u2.field;
523 	} else
524 		nlen = olen;
525 
526 	p = (char *) alloc(nlen + 1, ATEMP);
527 	if (vp->flag & (RJUST|LJUST)) {
528 		int slen;
529 
530 		if (vp->flag & RJUST) {
531 			const char *r = s + olen;
532 			/* strip trailing spaces (at&t ksh uses q[-1] == ' ') */
533 			while (r > s && isspace((unsigned char)r[-1]))
534 				--r;
535 			slen = r - s;
536 			if (slen > vp->u2.field) {
537 				s += slen - vp->u2.field;
538 				slen = vp->u2.field;
539 			}
540 			shf_snprintf(p, nlen + 1,
541 				((vp->flag & ZEROFIL) && digit(*s)) ?
542 					  "%0*s%.*s" : "%*s%.*s",
543 				vp->u2.field - slen, null, slen, s);
544 		} else {
545 			/* strip leading spaces/zeros */
546 			while (isspace((unsigned char)*s))
547 				s++;
548 			if (vp->flag & ZEROFIL)
549 				while (*s == '0')
550 					s++;
551 			shf_snprintf(p, nlen + 1, "%-*.*s",
552 				vp->u2.field, vp->u2.field, s);
553 		}
554 	} else
555 		memcpy(p, s, olen + 1);
556 
557 	if (vp->flag & UCASEV_AL) {
558 		for (q = p; *q; q++)
559 			if (islower((unsigned char)*q))
560 				*q = toupper((unsigned char)*q);
561 	} else if (vp->flag & LCASEV) {
562 		for (q = p; *q; q++)
563 			if (isupper((unsigned char)*q))
564 				*q = tolower((unsigned char)*q);
565 	}
566 
567 	return p;
568 }
569 
570 /*
571  * make vp->val.s be "name=value" for quick exporting.
572  */
573 static void
574 export(vp, val)
575 	register struct tbl *vp;
576 	const char *val;
577 {
578 	register char *xp;
579 	char *op = (vp->flag&ALLOC) ? vp->val.s : NULL;
580 	int namelen = strlen(vp->name);
581 	int vallen = strlen(val) + 1;
582 
583 	vp->flag |= ALLOC;
584 	xp = (char*)alloc(namelen + 1 + vallen, vp->areap);
585 	memcpy(vp->val.s = xp, vp->name, namelen);
586 	xp += namelen;
587 	*xp++ = '=';
588 	vp->type = xp - vp->val.s; /* offset to value */
589 	memcpy(xp, val, vallen);
590 	if (op != NULL)
591 		afree((void*)op, vp->areap);
592 }
593 
594 /*
595  * lookup variable (according to (set&LOCAL)),
596  * set its attributes (INTEGER, RDONLY, EXPORT, TRACE, LJUST, RJUST, ZEROFIL,
597  * LCASEV, UCASEV_AL), and optionally set its value if an assignment.
598  */
599 struct tbl *
600 typeset(var, set, clr, field, base)
601 	register const char *var;
602 	Tflag clr, set;
603 	int field, base;
604 {
605 	register struct tbl *vp;
606 	struct tbl *vpbase, *t;
607 	char *tvar;
608 	const char *val;
609 
610 	/* check for valid variable name, search for value */
611 	val = skip_varname(var, FALSE);
612 	if (val == var)
613 		return NULL;
614 	if (*val == '[') {
615 		int len;
616 
617 		len = array_ref_len(val);
618 		if (len == 0)
619 			return NULL;
620 		/* IMPORT is only used when the shell starts up and is
621 		 * setting up its environment.  Allow only simple array
622 		 * references at this time since parameter/command substitution
623 		 * is preformed on the [expression], which would be a major
624 		 * security hole.
625 		 */
626 		if (set & IMPORT) {
627 			int i;
628 			for (i = 1; i < len - 1; i++)
629 				if (!digit(val[i]))
630 					return NULL;
631 		}
632 		val += len;
633 	}
634 	if (*val == '=')
635 		tvar = str_nsave(var, val++ - var, ATEMP);
636 	else {
637 		/* Importing from original environment: must have an = */
638 		if (set & IMPORT)
639 			return NULL;
640 		tvar = (char *) __UNCONST(var);
641 		val = NULL;
642 	}
643 
644 	/* Prevent typeset from creating a local PATH/ENV/SHELL */
645 	if (Flag(FRESTRICTED) && (strcmp(tvar, "PATH") == 0
646 				  || strcmp(tvar, "ENV") == 0
647 				  || strcmp(tvar, "SHELL") == 0))
648 		errorf("%s: restricted", tvar);
649 
650 	vp = (set&LOCAL) ? local(tvar, (set & LOCAL_COPY) ? TRUE : FALSE)
651 		: global(tvar);
652 	set &= ~(LOCAL|LOCAL_COPY);
653 
654 	vpbase = (vp->flag & ARRAY) ? global(arrayname(var)) : vp;
655 
656 	/* only allow export flag to be set.  at&t ksh allows any attribute to
657 	 * be changed, which means it can be truncated or modified
658 	 * (-L/-R/-Z/-i).
659 	 */
660 	if ((vpbase->flag&RDONLY)
661 	    && (val || clr || (set & ~EXPORT)))
662 		/* XXX check calls - is error here ok by POSIX? */
663 		errorf("%s: is read only", tvar);
664 	if (val)
665 		afree(tvar, ATEMP);
666 
667 	/* most calls are with set/clr == 0 */
668 	if (set | clr) {
669 		int ok = 1;
670 		/* XXX if x[0] isn't set, there will be problems: need to have
671 		 * one copy of attributes for arrays...
672 		 */
673 		for (t = vpbase; t; t = t->u.array) {
674 			int fake_assign;
675 			char UNINITIALIZED(*s);
676 			char UNINITIALIZED(*free_me);
677 
678 			fake_assign = (t->flag & ISSET) && (!val || t != vp)
679 				      && ((set & (UCASEV_AL|LCASEV|LJUST|RJUST|ZEROFIL))
680 					  || ((t->flag & INTEGER) && (clr & INTEGER))
681 					  || (!(t->flag & INTEGER) && (set & INTEGER)));
682 			if (fake_assign) {
683 				if (t->flag & INTEGER) {
684 					s = str_val(t);
685 					free_me = (char *) 0;
686 				} else {
687 					s = t->val.s + t->type;
688 					free_me = (t->flag & ALLOC) ? t->val.s
689 								  : (char *) 0;
690 				}
691 				t->flag &= ~ALLOC;
692 			}
693 			if (!(t->flag & INTEGER) && (set & INTEGER)) {
694 				t->type = 0;
695 				t->flag &= ~ALLOC;
696 			}
697 			t->flag = (t->flag | set) & ~clr;
698 			/* Don't change base if assignment is to be done,
699 			 * in case assignment fails.
700 			 */
701 			if ((set & INTEGER) && base > 0 && (!val || t != vp))
702 				t->type = base;
703 			if (set & (LJUST|RJUST|ZEROFIL))
704 				t->u2.field = field;
705 			if (fake_assign) {
706 				if (!setstr(t, s, KSH_RETURN_ERROR)) {
707 					/* Somewhat arbitrary action here:
708 					 * zap contents of variable, but keep
709 					 * the flag settings.
710 					 */
711 					ok = 0;
712 					if (t->flag & INTEGER)
713 						t->flag &= ~ISSET;
714 					else {
715 						if (t->flag & ALLOC)
716 							afree((void*) t->val.s,
717 							      t->areap);
718 						t->flag &= ~(ISSET|ALLOC);
719 						t->type = 0;
720 					}
721 				}
722 				if (free_me)
723 					afree((void *) free_me, t->areap);
724 			}
725 		}
726 		if (!ok)
727 		    errorf(null);
728 	}
729 
730 	if (val != NULL) {
731 		if (vp->flag&INTEGER) {
732 			/* do not zero base before assignment */
733 			setstr(vp, val, KSH_UNWIND_ERROR | 0x4);
734 			/* Done after assignment to override default */
735 			if (base > 0)
736 				vp->type = base;
737 		} else
738 			/* setstr can't fail (readonly check already done) */
739 			setstr(vp, val, KSH_RETURN_ERROR | 0x4);
740 	}
741 
742 	/* only x[0] is ever exported, so use vpbase */
743 	if ((vpbase->flag&EXPORT) && !(vpbase->flag&INTEGER)
744 	    && vpbase->type == 0)
745 		export(vpbase, (vpbase->flag&ISSET) ? vpbase->val.s : null);
746 
747 	return vp;
748 }
749 
750 /* Unset a variable.  array_ref is set if there was an array reference in
751  * the name lookup (eg, x[2]).
752  */
753 void
754 unset(vp, array_ref)
755 	register struct tbl *vp;
756 	int array_ref;
757 {
758 	if (vp->flag & ALLOC)
759 		afree((void*)vp->val.s, vp->areap);
760 	if ((vp->flag & ARRAY) && !array_ref) {
761 		struct tbl *a, *tmp;
762 
763 		/* Free up entire array */
764 		for (a = vp->u.array; a; ) {
765 			tmp = a;
766 			a = a->u.array;
767 			if (tmp->flag & ALLOC)
768 				afree((void *) tmp->val.s, tmp->areap);
769 			afree(tmp, tmp->areap);
770 		}
771 		vp->u.array = (struct tbl *) 0;
772 	}
773 	/* If foo[0] is being unset, the remainder of the array is kept... */
774 	vp->flag &= SPECIAL | (array_ref ? ARRAY|DEFINED : 0);
775 	if (vp->flag & SPECIAL)
776 		unsetspec(vp);	/* responsible for `unspecial'ing var */
777 }
778 
779 /* return a pointer to the first char past a legal variable name (returns the
780  * argument if there is no legal name, returns * a pointer to the terminating
781  * null if whole string is legal).
782  */
783 char *
784 skip_varname(s, aok)
785 	const char *s;
786 	int aok;
787 {
788 	int alen;
789 
790 	if (s && letter(*s)) {
791 		while (*++s && letnum(*s))
792 			;
793 		if (aok && *s == '[' && (alen = array_ref_len(s)))
794 			s += alen;
795 	}
796 	return (char *) __UNCONST(s);
797 }
798 
799 /* Return a pointer to the first character past any legal variable name.  */
800 char *
801 skip_wdvarname(s, aok)
802 	const char *s;
803 	int aok;	/* skip array de-reference? */
804 {
805 	if (s[0] == CHAR && letter(s[1])) {
806 		do
807 			s += 2;
808 		while (s[0] == CHAR && letnum(s[1]));
809 		if (aok && s[0] == CHAR && s[1] == '[') {
810 			/* skip possible array de-reference */
811 			const char *p = s;
812 			char c;
813 			int depth = 0;
814 
815 			while (1) {
816 				if (p[0] != CHAR)
817 					break;
818 				c = p[1];
819 				p += 2;
820 				if (c == '[')
821 					depth++;
822 				else if (c == ']' && --depth == 0) {
823 					s = p;
824 					break;
825 				}
826 			}
827 		}
828 	}
829 	return (char *) __UNCONST(s);
830 }
831 
832 /* Check if coded string s is a variable name */
833 int
834 is_wdvarname(s, aok)
835 	const char *s;
836 	int aok;
837 {
838 	char *p = skip_wdvarname(s, aok);
839 
840 	return p != s && p[0] == EOS;
841 }
842 
843 /* Check if coded string s is a variable assignment */
844 int
845 is_wdvarassign(s)
846 	const char *s;
847 {
848 	char *p = skip_wdvarname(s, TRUE);
849 
850 	return p != s && p[0] == CHAR && p[1] == '=';
851 }
852 
853 /*
854  * Make the exported environment from the exported names in the dictionary.
855  */
856 char **
857 makenv()
858 {
859 	struct block *l = e->loc;
860 	XPtrV env;
861 	register struct tbl *vp, **vpp;
862 	register int i;
863 
864 	XPinit(env, 64);
865 	for (l = e->loc; l != NULL; l = l->next)
866 		for (vpp = l->vars.tbls, i = l->vars.size; --i >= 0; )
867 			if ((vp = *vpp++) != NULL
868 			    && (vp->flag&(ISSET|EXPORT)) == (ISSET|EXPORT)) {
869 				register struct block *l2;
870 				register struct tbl *vp2;
871 				unsigned h = hash(vp->name);
872 
873 				/* unexport any redefined instances */
874 				for (l2 = l->next; l2 != NULL; l2 = l2->next) {
875 					vp2 = tsearch(&l2->vars, vp->name, h);
876 					if (vp2 != NULL)
877 						vp2->flag &= ~EXPORT;
878 				}
879 				if ((vp->flag&INTEGER)) {
880 					/* integer to string */
881 					char *val;
882 					val = str_val(vp);
883 					vp->flag &= ~(INTEGER|RDONLY);
884 					/* setstr can't fail here */
885 					setstr(vp, val, KSH_RETURN_ERROR);
886 				}
887 				XPput(env, vp->val.s);
888 			}
889 	XPput(env, NULL);
890 	return (char **) XPclose(env);
891 }
892 
893 /*
894  * Called after a fork in parent to bump the random number generator.
895  * Done to ensure children will not get the same random number sequence
896  * if the parent doesn't use $RANDOM.
897  */
898 void
899 change_random()
900 {
901     rand();
902 }
903 
904 /*
905  * handle special variables with side effects - PATH, SECONDS.
906  */
907 
908 /* Test if name is a special parameter */
909 static int
910 special(name)
911 	register const char * name;
912 {
913 	register struct tbl *tp;
914 
915 	tp = tsearch(&specials, name, hash(name));
916 	return tp && (tp->flag & ISSET) ? tp->type : V_NONE;
917 }
918 
919 /* Make a variable non-special */
920 static void
921 unspecial(name)
922 	register const char * name;
923 {
924 	register struct tbl *tp;
925 
926 	tp = tsearch(&specials, name, hash(name));
927 	if (tp)
928 		tdelete(tp);
929 }
930 
931 #ifdef KSH
932 static	time_t	seconds;		/* time SECONDS last set */
933 #endif /* KSH */
934 static	int	user_lineno;		/* what user set $LINENO to */
935 
936 static void
937 getspec(vp)
938 	register struct tbl *vp;
939 {
940 	switch (special(vp->name)) {
941 #ifdef KSH
942 	  case V_SECONDS:
943 		vp->flag &= ~SPECIAL;
944 		/* On start up the value of SECONDS is used before seconds
945 		 * has been set - don't do anything in this case
946 		 * (see initcoms[] in main.c).
947 		 */
948 		if (vp->flag & ISSET)
949 			setint(vp, (long) (time((time_t *)0) - seconds));
950 		vp->flag |= SPECIAL;
951 		break;
952 	  case V_RANDOM:
953 		vp->flag &= ~SPECIAL;
954 		setint(vp, (long) (rand() & 0x7fff));
955 		vp->flag |= SPECIAL;
956 		break;
957 #endif /* KSH */
958 #ifdef HISTORY
959 	  case V_HISTSIZE:
960 		vp->flag &= ~SPECIAL;
961 		setint(vp, (long) histsize);
962 		vp->flag |= SPECIAL;
963 		break;
964 #endif /* HISTORY */
965 	  case V_OPTIND:
966 		vp->flag &= ~SPECIAL;
967 		setint(vp, (long) user_opt.uoptind);
968 		vp->flag |= SPECIAL;
969 		break;
970 	  case V_LINENO:
971 		vp->flag &= ~SPECIAL;
972 		setint(vp, (long) current_lineno + user_lineno);
973 		vp->flag |= SPECIAL;
974 		break;
975 	}
976 }
977 
978 static void
979 setspec(vp)
980 	register struct tbl *vp;
981 {
982 	char *s;
983 
984 	switch (special(vp->name)) {
985 	  case V_PATH:
986 		if (path)
987 			afree(path, APERM);
988 		path = str_save(str_val(vp), APERM);
989 		flushcom(1);	/* clear tracked aliases */
990 		break;
991 	  case V_IFS:
992 		setctypes(s = str_val(vp), C_IFS);
993 		ifs0 = *s;
994 		break;
995 	  case V_OPTIND:
996 		vp->flag &= ~SPECIAL;
997 		getopts_reset((int) intval(vp));
998 		vp->flag |= SPECIAL;
999 		break;
1000 	  case V_POSIXLY_CORRECT:
1001 		change_flag(FPOSIX, OF_SPECIAL, 1);
1002 		break;
1003 	  case V_TMPDIR:
1004 		if (tmpdir) {
1005 			afree(tmpdir, APERM);
1006 			tmpdir = (char *) 0;
1007 		}
1008 		/* Use tmpdir iff it is an absolute path, is writable and
1009 		 * searchable and is a directory...
1010 		 */
1011 		{
1012 			struct stat statb;
1013 			s = str_val(vp);
1014 			if (ISABSPATH(s) && eaccess(s, W_OK|X_OK) == 0
1015 			    && stat(s, &statb) == 0 && S_ISDIR(statb.st_mode))
1016 				tmpdir = str_save(s, APERM);
1017 		}
1018 		break;
1019 #ifdef HISTORY
1020 	  case V_HISTSIZE:
1021 		vp->flag &= ~SPECIAL;
1022 		sethistsize((int) intval(vp));
1023 		vp->flag |= SPECIAL;
1024 		break;
1025 	  case V_HISTFILE:
1026 		sethistfile(str_val(vp));
1027 		break;
1028 #endif /* HISTORY */
1029 #ifdef EDIT
1030 	  case V_VISUAL:
1031 		set_editmode(str_val(vp));
1032 		break;
1033 	  case V_EDITOR:
1034 		if (!(global("VISUAL")->flag & ISSET))
1035 			set_editmode(str_val(vp));
1036 		break;
1037 	  case V_COLUMNS:
1038 		if ((x_cols = intval(vp)) <= MIN_COLS)
1039 			x_cols = MIN_COLS;
1040 		break;
1041 #endif /* EDIT */
1042 #ifdef KSH
1043 	  case V_MAIL:
1044 		mbset(str_val(vp));
1045 		break;
1046 	  case V_MAILPATH:
1047 		mpset(str_val(vp));
1048 		break;
1049 	  case V_MAILCHECK:
1050 		vp->flag &= ~SPECIAL;
1051 		mcset(intval(vp));
1052 		vp->flag |= SPECIAL;
1053 		break;
1054 	  case V_RANDOM:
1055 		vp->flag &= ~SPECIAL;
1056 		srand((unsigned int)intval(vp));
1057 		vp->flag |= SPECIAL;
1058 		break;
1059 	  case V_SECONDS:
1060 		vp->flag &= ~SPECIAL;
1061 		seconds = time((time_t*) 0) - intval(vp);
1062 		vp->flag |= SPECIAL;
1063 		break;
1064 	  case V_TMOUT:
1065 		/* at&t ksh seems to do this (only listen if integer) */
1066 		if (vp->flag & INTEGER)
1067 			ksh_tmout = vp->val.i >= 0 ? vp->val.i : 0;
1068 		break;
1069 #endif /* KSH */
1070 	  case V_LINENO:
1071 		vp->flag &= ~SPECIAL;
1072 		/* The -1 is because line numbering starts at 1. */
1073 		user_lineno = (unsigned int) intval(vp) - current_lineno - 1;
1074 		vp->flag |= SPECIAL;
1075 		break;
1076 	}
1077 }
1078 
1079 static void
1080 unsetspec(vp)
1081 	register struct tbl *vp;
1082 {
1083 	switch (special(vp->name)) {
1084 	  case V_PATH:
1085 		if (path)
1086 			afree(path, APERM);
1087 		path = str_save(def_path, APERM);
1088 		flushcom(1);	/* clear tracked aliases */
1089 		break;
1090 	  case V_IFS:
1091 		setctypes(" \t\n", C_IFS);
1092 		ifs0 = ' ';
1093 		break;
1094 	  case V_TMPDIR:
1095 		/* should not become unspecial */
1096 		if (tmpdir) {
1097 			afree(tmpdir, APERM);
1098 			tmpdir = (char *) 0;
1099 		}
1100 		break;
1101 #ifdef KSH
1102 	  case V_MAIL:
1103 		mbset((char *) 0);
1104 		break;
1105 	  case V_MAILPATH:
1106 		mpset((char *) 0);
1107 		break;
1108 #endif /* KSH */
1109 
1110 	  case V_LINENO:
1111 #ifdef KSH
1112 	  case V_MAILCHECK:	/* at&t ksh leaves previous value in place */
1113 	  case V_RANDOM:
1114 	  case V_SECONDS:
1115 	  case V_TMOUT:		/* at&t ksh leaves previous value in place */
1116 #endif /* KSH */
1117 		unspecial(vp->name);
1118 		break;
1119 
1120 	  /* at&t ksh man page says OPTIND, OPTARG and _ lose special meaning,
1121 	   * but OPTARG does not (still set by getopts) and _ is also still
1122 	   * set in various places.
1123 	   * Don't know what at&t does for:
1124 	   *		MAIL, MAILPATH, HISTSIZE, HISTFILE,
1125 	   * Unsetting these in at&t ksh does not loose the `specialness':
1126 	   *    no effect: IFS, COLUMNS, PATH, TMPDIR,
1127 	   *		VISUAL, EDITOR,
1128 	   * pdkshisms: no effect:
1129 	   *		POSIXLY_CORRECT (use set +o posix instead)
1130 	   */
1131 	}
1132 }
1133 
1134 /*
1135  * Search for (and possibly create) a table entry starting with
1136  * vp, indexed by val.
1137  */
1138 static struct tbl *
1139 arraysearch(vp, val)
1140 	struct tbl *vp;
1141 	int val;
1142 {
1143 	struct tbl *prev, *curr, *new;
1144 	size_t namelen = strlen(vp->name) + 1;
1145 
1146 	vp->flag |= ARRAY|DEFINED;
1147 
1148 	/* The table entry is always [0] */
1149 	if (val == 0) {
1150 		vp->index = 0;
1151 		return vp;
1152 	}
1153 	prev = vp;
1154 	curr = vp->u.array;
1155 	while (curr && curr->index < val) {
1156 		prev = curr;
1157 		curr = curr->u.array;
1158 	}
1159 	if (curr && curr->index == val) {
1160 		if (curr->flag&ISSET)
1161 			return curr;
1162 		else
1163 			new = curr;
1164 	} else
1165 		new = (struct tbl *)alloc(sizeof(struct tbl) + namelen,
1166 		    vp->areap);
1167 	strlcpy(new->name, vp->name, namelen);
1168 	new->flag = vp->flag & ~(ALLOC|DEFINED|ISSET|SPECIAL);
1169 	new->type = vp->type;
1170 	new->areap = vp->areap;
1171 	new->u2.field = vp->u2.field;
1172 	new->index = val;
1173 	if (curr != new) {		/* not reusing old array entry */
1174 		prev->u.array = new;
1175 		new->u.array = curr;
1176 	}
1177 	return new;
1178 }
1179 
1180 /* Return the length of an array reference (eg, [1+2]) - cp is assumed
1181  * to point to the open bracket.  Returns 0 if there is no matching closing
1182  * bracket.
1183  */
1184 int
1185 array_ref_len(cp)
1186 	const char *cp;
1187 {
1188 	const char *s = cp;
1189 	int c;
1190 	int depth = 0;
1191 
1192 	while ((c = *s++) && (c != ']' || --depth))
1193 		if (c == '[')
1194 			depth++;
1195 	if (!c)
1196 		return 0;
1197 	return s - cp;
1198 }
1199 
1200 /*
1201  * Make a copy of the base of an array name
1202  */
1203 char *
1204 arrayname(str)
1205 	const char *str;
1206 {
1207 	const char *p;
1208 
1209 	if ((p = strchr(str, '[')) == 0)
1210 		/* Shouldn't happen, but why worry? */
1211 		return (char *) __UNCONST(str);
1212 
1213 	return str_nsave(str, p - str, ATEMP);
1214 }
1215 
1216 /* Set (or overwrite, if !reset) the array variable var to the values in vals.
1217  */
1218 void
1219 set_array(var, reset, vals)
1220 	const char *var;
1221 	int reset;
1222 	char **vals;
1223 {
1224 	struct tbl *vp, *vq;
1225 	int i;
1226 
1227 	/* to get local array, use "typeset foo; set -A foo" */
1228 	vp = global(var);
1229 
1230 	/* Note: at&t ksh allows set -A but not set +A of a read-only var */
1231 	if ((vp->flag&RDONLY))
1232 		errorf("%s: is read only", var);
1233 	/* This code is quite non-optimal */
1234 	if (reset > 0)
1235 		/* trash existing values and attributes */
1236 		unset(vp, 0);
1237 	/* todo: would be nice for assignment to completely succeed or
1238 	 * completely fail.  Only really effects integer arrays:
1239 	 * evaluation of some of vals[] may fail...
1240 	 */
1241 	for (i = 0; vals[i]; i++) {
1242 		vq = arraysearch(vp, i);
1243 		/* would be nice to deal with errors here... (see above) */
1244 		setstr(vq, vals[i], KSH_RETURN_ERROR);
1245 	}
1246 }
1247