xref: /netbsd/bin/ksh/var.c (revision bf9ec67e) 
1 /*	$NetBSD: var.c,v 1.7 2000/11/02 01:10:08 christos Exp $	*/
2 
3 #include "sh.h"
4 #include "ksh_time.h"
5 #include "ksh_limval.h"
6 #include "ksh_stat.h"
7 #include <ctype.h>
8 
9 /*
10  * Variables
11  *
12  * WARNING: unreadable code, needs a rewrite
13  *
14  * if (flag&INTEGER), val.i contains integer value, and type contains base.
15  * otherwise, (val.s + type) contains string value.
16  * if (flag&EXPORT), val.s contains "name=value" for E-Z exporting.
17  */
18 static	struct tbl vtemp;
19 static	struct table specials;
20 static char	*formatstr	ARGS((struct tbl *vp, const char *s));
21 static void	export		ARGS((struct tbl *vp, const char *val));
22 static int	special		ARGS((const char *name));
23 static void	unspecial	ARGS((const char *name));
24 static void	getspec		ARGS((struct tbl *vp));
25 static void	setspec		ARGS((struct tbl *vp));
26 static void	unsetspec	ARGS((struct tbl *vp));
27 static struct tbl *arraysearch  ARGS((struct tbl *, int));
28 static const char *array_index_calc ARGS((const char *, bool_t *, int *));
29 
30 /*
31  * create a new block for function calls and simple commands
32  * assume caller has allocated and set up e->loc
33  */
34 void
35 newblock()
36 {
37 	register struct block *l;
38 	static char *const empty[] = {null};
39 
40 	l = (struct block *) alloc(sizeof(struct block), ATEMP);
41 	l->flags = 0;
42 	ainit(&l->area); /* todo: could use e->area (l->area => l->areap) */
43 	if (!e->loc) {
44 		l->argc = 0;
45 		l->argv = (char **) empty;
46 	} else {
47 		l->argc = e->loc->argc;
48 		l->argv = e->loc->argv;
49 	}
50 	l->exit = l->error = NULL;
51 	tinit(&l->vars, &l->area, 0);
52 	tinit(&l->funs, &l->area, 0);
53 	l->next = e->loc;
54 	e->loc = l;
55 }
56 
57 /*
58  * pop a block handling special variables
59  */
60 void
61 popblock()
62 {
63 	register struct block *l = e->loc;
64 	register struct tbl *vp, **vpp = l->vars.tbls, *vq;
65 	register int i;
66 
67 	e->loc = l->next;	/* pop block */
68 	for (i = l->vars.size; --i >= 0; ) {
69 		if ((vp = *vpp++) != NULL && (vp->flag&SPECIAL)) {
70 			if ((vq = global(vp->name))->flag & ISSET)
71 				setspec(vq);
72 			else
73 				unsetspec(vq);
74 		}
75 	}
76 	if (l->flags & BF_DOGETOPTS)
77 		user_opt = l->getopts_state;
78 	afreeall(&l->area);
79 	afree(l, ATEMP);
80 }
81 
82 /* called by main() to initialize variable data structures */
83 void
84 initvar()
85 {
86 	static const struct {
87 		const char *name;
88 		int v;
89 	} names[] = {
90 			{ "COLUMNS",		V_COLUMNS },
91 			{ "IFS",		V_IFS },
92 			{ "OPTIND",		V_OPTIND },
93 			{ "PATH",		V_PATH },
94 			{ "POSIXLY_CORRECT",	V_POSIXLY_CORRECT },
95 			{ "TMPDIR",		V_TMPDIR },
96 #ifdef HISTORY
97 			{ "HISTFILE",		V_HISTFILE },
98 			{ "HISTSIZE",		V_HISTSIZE },
99 #endif /* HISTORY */
100 #ifdef EDIT
101 			{ "EDITOR",		V_EDITOR },
102 			{ "VISUAL",		V_VISUAL },
103 #endif /* EDIT */
104 #ifdef KSH
105 			{ "MAIL",		V_MAIL },
106 			{ "MAILCHECK",		V_MAILCHECK },
107 			{ "MAILPATH",		V_MAILPATH },
108 			{ "RANDOM",		V_RANDOM },
109 			{ "SECONDS",		V_SECONDS },
110 			{ "TMOUT",		V_TMOUT },
111 #endif /* KSH */
112 			{ "LINENO",		V_LINENO },
113 			{ (char *) 0,	0 }
114 		};
115 	int i;
116 	struct tbl *tp;
117 
118 	tinit(&specials, APERM, 32); /* must be 2^n (currently 17 specials) */
119 	for (i = 0; names[i].name; i++) {
120 		tp = tenter(&specials, names[i].name, hash(names[i].name));
121 		tp->flag = DEFINED|ISSET;
122 		tp->type = names[i].v;
123 	}
124 }
125 
126 /* Used to calculate an array index for global()/local().  Sets *arrayp to
127  * non-zero if this is an array, sets *valp to the array index, returns
128  * the basename of the array.
129  */
130 static const char *
131 array_index_calc(n, arrayp, valp)
132 	const char *n;
133 	bool_t *arrayp;
134 	int *valp;
135 {
136 	const char *p;
137 	int len;
138 
139 	*arrayp = FALSE;
140 	p = skip_varname(n, FALSE);
141 	if (p != n && *p == '[' && (len = array_ref_len(p))) {
142 		char *sub, *tmp;
143 		long rval;
144 
145 		/* Calculate the value of the subscript */
146 		*arrayp = TRUE;
147 		tmp = str_nsave(p+1, len-2, ATEMP);
148 		sub = substitute(tmp, 0);
149 		afree(tmp, ATEMP);
150 		n = str_nsave(n, p - n, ATEMP);
151 		evaluate(sub, &rval, KSH_UNWIND_ERROR);
152 		if (rval < 0 || rval > ARRAYMAX)
153 			errorf("%s: subscript out of range", n);
154 		*valp = rval;
155 		afree(sub, ATEMP);
156 	}
157 	return n;
158 }
159 
160 /*
161  * Search for variable, if not found create globally.
162  */
163 struct tbl *
164 global(n)
165 	register const char *n;
166 {
167 	register struct block *l = e->loc;
168 	register struct tbl *vp;
169 	register int c;
170 	unsigned h;
171 	bool_t	 array;
172 	int	 val;
173 
174 	/* Check to see if this is an array */
175 	n = array_index_calc(n, &array, &val);
176 	h = hash(n);
177 	c = n[0];
178 	if (!letter(c)) {
179 		if (array)
180 			errorf("bad substitution");
181 		vp = &vtemp;
182 		vp->flag = DEFINED;
183 		vp->type = 0;
184 		vp->areap = ATEMP;
185 		*vp->name = c;
186 		if (digit(c)) {
187 			for (c = 0; digit(*n); n++)
188 				c = c*10 + *n-'0';
189 			if (c <= l->argc)
190 				/* setstr can't fail here */
191 				setstr(vp, l->argv[c], KSH_RETURN_ERROR);
192 			vp->flag |= RDONLY;
193 			return vp;
194 		}
195 		vp->flag |= RDONLY;
196 		if (n[1] != '\0')
197 			return vp;
198 		vp->flag |= ISSET|INTEGER;
199 		switch (c) {
200 		  case '$':
201 			vp->val.i = kshpid;
202 			break;
203 		  case '!':
204 			/* If no job, expand to nothing */
205 			if ((vp->val.i = j_async()) == 0)
206 				vp->flag &= ~(ISSET|INTEGER);
207 			break;
208 		  case '?':
209 			vp->val.i = exstat;
210 			break;
211 		  case '#':
212 			vp->val.i = l->argc;
213 			break;
214 		  case '-':
215 			vp->flag &= ~INTEGER;
216 			vp->val.s = getoptions();
217 			break;
218 		  default:
219 			vp->flag &= ~(ISSET|INTEGER);
220 		}
221 		return vp;
222 	}
223 	for (l = e->loc; ; l = l->next) {
224 		vp = tsearch(&l->vars, n, h);
225 		if (vp != NULL) {
226 			if (array)
227 				return arraysearch(vp, val);
228 			else
229 				return vp;
230 		}
231 		if (l->next == NULL)
232 			break;
233 	}
234 	vp = tenter(&l->vars, n, h);
235 	if (array)
236 		vp = arraysearch(vp, val);
237 	vp->flag |= DEFINED;
238 	if (special(n))
239 		vp->flag |= SPECIAL;
240 	return vp;
241 }
242 
243 /*
244  * Search for local variable, if not found create locally.
245  */
246 struct tbl *
247 local(n, copy)
248 	register const char *n;
249 	bool_t copy;
250 {
251 	register struct block *l = e->loc;
252 	register struct tbl *vp;
253 	unsigned h;
254 	bool_t	 array;
255 	int	 val;
256 
257 	/* Check to see if this is an array */
258 	n = array_index_calc(n, &array, &val);
259 	h = hash(n);
260 	if (!letter(*n)) {
261 		vp = &vtemp;
262 		vp->flag = DEFINED|RDONLY;
263 		vp->type = 0;
264 		vp->areap = ATEMP;
265 		return vp;
266 	}
267 	vp = tenter(&l->vars, n, h);
268 	if (copy && !(vp->flag & DEFINED)) {
269 		struct block *ll = l;
270 		struct tbl *vq = (struct tbl *) 0;
271 
272 		while ((ll = ll->next) && !(vq = tsearch(&ll->vars, n, h)))
273 			;
274 		if (vq) {
275 			vp->flag |= vq->flag & (EXPORT|INTEGER|RDONLY
276 						|LJUST|RJUST|ZEROFIL
277 						|LCASEV|UCASEV_AL|INT_U|INT_L);
278 			if (vq->flag & INTEGER)
279 				vp->type = vq->type;
280 			vp->u2.field = vq->u2.field;
281 		}
282 	}
283 	if (array)
284 		vp = arraysearch(vp, val);
285 	vp->flag |= DEFINED;
286 	if (special(n))
287 		vp->flag |= SPECIAL;
288 	return vp;
289 }
290 
291 /* get variable string value */
292 char *
293 str_val(vp)
294 	register struct tbl *vp;
295 {
296 	char *s;
297 
298 	if ((vp->flag&SPECIAL))
299 		getspec(vp);
300 	if (!(vp->flag&ISSET))
301 		s = null;		/* special to dollar() */
302 	else if (!(vp->flag&INTEGER))	/* string source */
303 		s = vp->val.s + vp->type;
304 	else {				/* integer source */
305 		/* worst case number length is when base=2, so use BITS(long) */
306 			     /* minus base #     number    null */
307 		static char strbuf[1 + 2 + 1 + BITS(long) + 1];
308 		const char *digits = (vp->flag & UCASEV_AL) ?
309 				  "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
310 				: "0123456789abcdefghijklmnopqrstuvwxyz";
311 		register unsigned long n;
312 		register int base;
313 
314 		s = strbuf + sizeof(strbuf);
315 		if (vp->flag & INT_U)
316 			n = (unsigned long) vp->val.i;
317 		else
318 			n = (vp->val.i < 0) ? -vp->val.i : vp->val.i;
319 		base = (vp->type == 0) ? 10 : vp->type;
320 
321 		*--s = '\0';
322 		do {
323 			*--s = digits[n % base];
324 			n /= base;
325 		} while (n != 0);
326 		if (base != 10) {
327 			*--s = '#';
328 			*--s = digits[base % 10];
329 			if (base >= 10)
330 				*--s = digits[base / 10];
331 		}
332 		if (!(vp->flag & INT_U) && vp->val.i < 0)
333 			*--s = '-';
334 		if (vp->flag & (RJUST|LJUST)) /* case already dealt with */
335 			s = formatstr(vp, s);
336 	}
337 	return s;
338 }
339 
340 /* get variable integer value, with error checking */
341 long
342 intval(vp)
343 	register struct tbl *vp;
344 {
345 	long num;
346 	int base;
347 
348 	base = getint(vp, &num);
349 	if (base == -1)
350 		/* XXX check calls - is error here ok by POSIX? */
351 		errorf("%s: bad number", str_val(vp));
352 	return num;
353 }
354 
355 /* set variable to string value */
356 int
357 setstr(vq, s, error_ok)
358 	register struct tbl *vq;
359 	const char *s;
360 	int error_ok;
361 {
362 	int no_ro_check = error_ok & 0x4;
363 	error_ok &= ~0x4;
364 	if ((vq->flag & RDONLY) && !no_ro_check) {
365 		warningf(TRUE, "%s: is read only", vq->name);
366 		if (!error_ok)
367 			errorf(null);
368 		return 0;
369 	}
370 	if (!(vq->flag&INTEGER)) { /* string dest */
371 		if ((vq->flag&ALLOC)) {
372 			/* debugging */
373 			if (s >= vq->val.s
374 			    && s <= vq->val.s + strlen(vq->val.s))
375 				internal_errorf(TRUE,
376 				    "setstr: %s=%s: assigning to self",
377 				    vq->name, s);
378 			afree((void*)vq->val.s, vq->areap);
379 		}
380 		vq->flag &= ~(ISSET|ALLOC);
381 		vq->type = 0;
382 		if (s && (vq->flag & (UCASEV_AL|LCASEV|LJUST|RJUST)))
383 			s = formatstr(vq, s);
384 		if ((vq->flag&EXPORT))
385 			export(vq, s);
386 		else {
387 			vq->val.s = str_save(s, vq->areap);
388 			if (vq->val.s)		/* <sjg> don't lie */
389 				vq->flag |= ALLOC;
390 		}
391 	} else			/* integer dest */
392 		if (!v_evaluate(vq, s, error_ok))
393 			return 0;
394 	vq->flag |= ISSET;
395 	if ((vq->flag&SPECIAL))
396 		setspec(vq);
397 	return 1;
398 }
399 
400 /* set variable to integer */
401 void
402 setint(vq, n)
403 	register struct tbl *vq;
404 	long n;
405 {
406 	if (!(vq->flag&INTEGER)) {
407 		register struct tbl *vp = &vtemp;
408 		vp->flag = (ISSET|INTEGER);
409 		vp->type = 0;
410 		vp->areap = ATEMP;
411 		vp->val.i = n;
412 		/* setstr can't fail here */
413 		setstr(vq, str_val(vp), KSH_RETURN_ERROR);
414 	} else
415 		vq->val.i = n;
416 	vq->flag |= ISSET;
417 	if ((vq->flag&SPECIAL))
418 		setspec(vq);
419 }
420 
421 int
422 getint(vp, nump)
423 	struct tbl *vp;
424 	long *nump;
425 {
426 	register char *s;
427 	register int c;
428 	int base, neg;
429 	int have_base = 0;
430 	long num;
431 
432 	if (vp->flag&SPECIAL)
433 		getspec(vp);
434 	/* XXX is it possible for ISSET to be set and val.s to be 0? */
435 	if (!(vp->flag&ISSET) || (!(vp->flag&INTEGER) && vp->val.s == NULL))
436 		return -1;
437 	if (vp->flag&INTEGER) {
438 		*nump = vp->val.i;
439 		return vp->type;
440 	}
441 	s = vp->val.s + vp->type;
442 	if (s == NULL)	/* redundent given initial test */
443 		s = null;
444 	base = 10;
445 	num = 0;
446 	neg = 0;
447 	for (c = *s++; c ; c = *s++) {
448 		if (c == '-') {
449 			neg++;
450 		} else if (c == '#') {
451 			base = (int) num;
452 			if (have_base || base < 2 || base > 36)
453 				return -1;
454 			num = 0;
455 			have_base = 1;
456 		} else if (letnum(c)) {
457 			if (isdigit(c))
458 				c -= '0';
459 			else if (islower(c))
460 				c -= 'a' - 10; /* todo: assumes ascii */
461 			else if (isupper(c))
462 				c -= 'A' - 10; /* todo: assumes ascii */
463 			else
464 				c = -1; /* _: force error */
465 			if (c < 0 || c >= base)
466 				return -1;
467 			num = num * base + c;
468 		} else
469 			return -1;
470 	}
471 	if (neg)
472 		num = -num;
473 	*nump = num;
474 	return base;
475 }
476 
477 /* convert variable vq to integer variable, setting its value from vp
478  * (vq and vp may be the same)
479  */
480 struct tbl *
481 setint_v(vq, vp)
482 	register struct tbl *vq, *vp;
483 {
484 	int base;
485 	long num;
486 
487 	if ((base = getint(vp, &num)) == -1)
488 		return NULL;
489 	if (!(vq->flag & INTEGER) && (vq->flag & ALLOC)) {
490 		vq->flag &= ~ALLOC;
491 		afree(vq->val.s, vq->areap);
492 	}
493 	vq->val.i = num;
494 	if (vq->type == 0) /* default base */
495 		vq->type = base;
496 	vq->flag |= ISSET|INTEGER;
497 	if (vq->flag&SPECIAL)
498 		setspec(vq);
499 	return vq;
500 }
501 
502 static char *
503 formatstr(vp, s)
504 	struct tbl *vp;
505 	const char *s;
506 {
507 	int olen, nlen;
508 	char *p, *q;
509 
510 	olen = strlen(s);
511 
512 	if (vp->flag & (RJUST|LJUST)) {
513 		if (!vp->u2.field)	/* default field width */
514 			vp->u2.field = olen;
515 		nlen = vp->u2.field;
516 	} else
517 		nlen = olen;
518 
519 	p = (char *) alloc(nlen + 1, ATEMP);
520 	if (vp->flag & (RJUST|LJUST)) {
521 		int slen;
522 
523 		if (vp->flag & RJUST) {
524 			const char *q = s + olen;
525 			/* strip trailing spaces (at&t ksh uses q[-1] == ' ') */
526 			while (q > s && isspace((unsigned char)q[-1]))
527 				--q;
528 			slen = q - s;
529 			if (slen > vp->u2.field) {
530 				s += slen - vp->u2.field;
531 				slen = vp->u2.field;
532 			}
533 			shf_snprintf(p, nlen + 1,
534 				((vp->flag & ZEROFIL) && digit(*s)) ?
535 					  "%0*s%.*s" : "%*s%.*s",
536 				vp->u2.field - slen, null, slen, s);
537 		} else {
538 			/* strip leading spaces/zeros */
539 			while (isspace((unsigned char)*s))
540 				s++;
541 			if (vp->flag & ZEROFIL)
542 				while (*s == '0')
543 					s++;
544 			shf_snprintf(p, nlen + 1, "%-*.*s",
545 				vp->u2.field, vp->u2.field, s);
546 		}
547 	} else
548 		memcpy(p, s, olen + 1);
549 
550 	if (vp->flag & UCASEV_AL) {
551 		for (q = p; *q; q++)
552 			if (islower((unsigned char)*q))
553 				*q = toupper(*q);
554 	} else if (vp->flag & LCASEV) {
555 		for (q = p; *q; q++)
556 			if (isupper((unsigned char)*q))
557 				*q = tolower(*q);
558 	}
559 
560 	return p;
561 }
562 
563 /*
564  * make vp->val.s be "name=value" for quick exporting.
565  */
566 static void
567 export(vp, val)
568 	register struct tbl *vp;
569 	const char *val;
570 {
571 	register char *xp;
572 	char *op = (vp->flag&ALLOC) ? vp->val.s : NULL;
573 	int namelen = strlen(vp->name);
574 	int vallen = strlen(val) + 1;
575 
576 	vp->flag |= ALLOC;
577 	xp = (char*)alloc(namelen + 1 + vallen, vp->areap);
578 	memcpy(vp->val.s = xp, vp->name, namelen);
579 	xp += namelen;
580 	*xp++ = '=';
581 	vp->type = xp - vp->val.s; /* offset to value */
582 	memcpy(xp, val, vallen);
583 	if (op != NULL)
584 		afree((void*)op, vp->areap);
585 }
586 
587 /*
588  * lookup variable (according to (set&LOCAL)),
589  * set its attributes (INTEGER, RDONLY, EXPORT, TRACE, LJUST, RJUST, ZEROFIL,
590  * LCASEV, UCASEV_AL), and optionally set its value if an assignment.
591  */
592 struct tbl *
593 typeset(var, set, clr, field, base)
594 	register const char *var;
595 	Tflag clr, set;
596 	int field, base;
597 {
598 	register struct tbl *vp;
599 	struct tbl *vpbase, *t;
600 	char *tvar;
601 	const char *val;
602 
603 	/* check for valid variable name, search for value */
604 	val = skip_varname(var, FALSE);
605 	if (val == var)
606 		return NULL;
607 	if (*val == '[') {
608 		int len;
609 
610 		len = array_ref_len(val);
611 		if (len == 0)
612 			return NULL;
613 		/* IMPORT is only used when the shell starts up and is
614 		 * setting up its environment.  Allow only simple array
615 		 * references at this time since parameter/command substitution
616 		 * is preformed on the [expression], which would be a major
617 		 * security hole.
618 		 */
619 		if (set & IMPORT) {
620 			int i;
621 			for (i = 1; i < len - 1; i++)
622 				if (!digit(val[i]))
623 					return NULL;
624 		}
625 		val += len;
626 	}
627 	if (*val == '=')
628 		tvar = str_nsave(var, val++ - var, ATEMP);
629 	else {
630 		/* Importing from original envirnment: must have an = */
631 		if (set & IMPORT)
632 			return NULL;
633 		tvar = (char *) var;
634 		val = NULL;
635 	}
636 
637 	/* Prevent typeset from creating a local PATH/ENV/SHELL */
638 	if (Flag(FRESTRICTED) && (strcmp(tvar, "PATH") == 0
639 				  || strcmp(tvar, "ENV") == 0
640 				  || strcmp(tvar, "SHELL") == 0))
641 		errorf("%s: restricted", tvar);
642 
643 	vp = (set&LOCAL) ? local(tvar, (set & LOCAL_COPY) ? TRUE : FALSE)
644 		: global(tvar);
645 	set &= ~(LOCAL|LOCAL_COPY);
646 
647 	vpbase = (vp->flag & ARRAY) ? global(arrayname(var)) : vp;
648 
649 	/* only allow export flag to be set.  at&t ksh allows any attribute to
650 	 * be changed, which means it can be truncated or modified
651 	 * (-L/-R/-Z/-i).
652 	 */
653 	if ((vpbase->flag&RDONLY)
654 	    && (val || clr || (set & ~EXPORT)))
655 		/* XXX check calls - is error here ok by POSIX? */
656 		errorf("%s: is read only", tvar);
657 	if (val)
658 		afree(tvar, ATEMP);
659 
660 	/* most calls are with set/clr == 0 */
661 	if (set | clr) {
662 		int ok = 1;
663 		/* XXX if x[0] isn't set, there will be problems: need to have
664 		 * one copy of attributes for arrays...
665 		 */
666 		for (t = vpbase; t; t = t->u.array) {
667 			int fake_assign;
668 			char UNINITIALIZED(*s);
669 			char UNINITIALIZED(*free_me);
670 
671 			fake_assign = (t->flag & ISSET) && (!val || t != vp)
672 				      && ((set & (UCASEV_AL|LCASEV|LJUST|RJUST|ZEROFIL))
673 					  || ((t->flag & INTEGER) && (clr & INTEGER))
674 					  || (!(t->flag & INTEGER) && (set & INTEGER)));
675 			if (fake_assign) {
676 				if (t->flag & INTEGER) {
677 					s = str_val(t);
678 					free_me = (char *) 0;
679 				} else {
680 					s = t->val.s + t->type;
681 					free_me = (t->flag & ALLOC) ? t->val.s
682 								  : (char *) 0;
683 				}
684 				t->flag &= ~ALLOC;
685 			}
686 			if (!(t->flag & INTEGER) && (set & INTEGER)) {
687 				t->type = 0;
688 				t->flag &= ~ALLOC;
689 			}
690 			t->flag = (t->flag | set) & ~clr;
691 			/* Don't change base if assignment is to be done,
692 			 * in case assignment fails.
693 			 */
694 			if ((set & INTEGER) && base > 0 && (!val || t != vp))
695 				t->type = base;
696 			if (set & (LJUST|RJUST|ZEROFIL))
697 				t->u2.field = field;
698 			if (fake_assign) {
699 				if (!setstr(t, s, KSH_RETURN_ERROR)) {
700 					/* Somewhat arbitrary action here:
701 					 * zap contents of varibale, but keep
702 					 * the flag settings.
703 					 */
704 					ok = 0;
705 					if (t->flag & INTEGER)
706 						t->flag &= ~ISSET;
707 					else {
708 						if (t->flag & ALLOC)
709 							afree((void*) t->val.s,
710 							      t->areap);
711 						t->flag &= ~(ISSET|ALLOC);
712 						t->type = 0;
713 					}
714 				}
715 				if (free_me)
716 					afree((void *) free_me, t->areap);
717 			}
718 		}
719 		if (!ok)
720 		    errorf(null);
721 	}
722 
723 	if (val != NULL) {
724 		if (vp->flag&INTEGER) {
725 			/* do not zero base before assignment */
726 			setstr(vp, val, KSH_UNWIND_ERROR | 0x4);
727 			/* Done after assignment to override default */
728 			if (base > 0)
729 				vp->type = base;
730 		} else
731 			/* setstr can't fail (readonly check already done) */
732 			setstr(vp, val, KSH_RETURN_ERROR | 0x4);
733 	}
734 
735 	/* only x[0] is ever exported, so use vpbase */
736 	if ((vpbase->flag&EXPORT) && !(vpbase->flag&INTEGER)
737 	    && vpbase->type == 0)
738 		export(vpbase, (vpbase->flag&ISSET) ? vpbase->val.s : null);
739 
740 	return vp;
741 }
742 
743 /* Unset a variable.  array_ref is set if there was an array reference in
744  * the name lookup (eg, x[2]).
745  */
746 void
747 unset(vp, array_ref)
748 	register struct tbl *vp;
749 	int array_ref;
750 {
751 	if (vp->flag & ALLOC)
752 		afree((void*)vp->val.s, vp->areap);
753 	if ((vp->flag & ARRAY) && !array_ref) {
754 		struct tbl *a, *tmp;
755 
756 		/* Free up entire array */
757 		for (a = vp->u.array; a; ) {
758 			tmp = a;
759 			a = a->u.array;
760 			if (tmp->flag & ALLOC)
761 				afree((void *) tmp->val.s, tmp->areap);
762 			afree(tmp, tmp->areap);
763 		}
764 		vp->u.array = (struct tbl *) 0;
765 	}
766 	/* If foo[0] is being unset, the remainder of the array is kept... */
767 	vp->flag &= SPECIAL | (array_ref ? ARRAY|DEFINED : 0);
768 	if (vp->flag & SPECIAL)
769 		unsetspec(vp);	/* responsible for `unspecial'ing var */
770 }
771 
772 /* return a pointer to the first char past a legal variable name (returns the
773  * argument if there is no legal name, returns * a pointer to the terminating
774  * null if whole string is legal).
775  */
776 char *
777 skip_varname(s, aok)
778 	const char *s;
779 	int aok;
780 {
781 	int alen;
782 
783 	if (s && letter(*s)) {
784 		while (*++s && letnum(*s))
785 			;
786 		if (aok && *s == '[' && (alen = array_ref_len(s)))
787 			s += alen;
788 	}
789 	return (char *) s;
790 }
791 
792 /* Return a pointer to the first character past any legal variable name.  */
793 char *
794 skip_wdvarname(s, aok)
795 	const char *s;
796 	int aok;	/* skip array de-reference? */
797 {
798 	if (s[0] == CHAR && letter(s[1])) {
799 		do
800 			s += 2;
801 		while (s[0] == CHAR && letnum(s[1]));
802 		if (aok && s[0] == CHAR && s[1] == '[') {
803 			/* skip possible array de-reference */
804 			const char *p = s;
805 			char c;
806 			int depth = 0;
807 
808 			while (1) {
809 				if (p[0] != CHAR)
810 					break;
811 				c = p[1];
812 				p += 2;
813 				if (c == '[')
814 					depth++;
815 				else if (c == ']' && --depth == 0) {
816 					s = p;
817 					break;
818 				}
819 			}
820 		}
821 	}
822 	return (char *) s;
823 }
824 
825 /* Check if coded string s is a variable name */
826 int
827 is_wdvarname(s, aok)
828 	const char *s;
829 	int aok;
830 {
831 	char *p = skip_wdvarname(s, aok);
832 
833 	return p != s && p[0] == EOS;
834 }
835 
836 /* Check if coded string s is a variable assignment */
837 int
838 is_wdvarassign(s)
839 	const char *s;
840 {
841 	char *p = skip_wdvarname(s, TRUE);
842 
843 	return p != s && p[0] == CHAR && p[1] == '=';
844 }
845 
846 /*
847  * Make the exported environment from the exported names in the dictionary.
848  */
849 char **
850 makenv()
851 {
852 	struct block *l = e->loc;
853 	XPtrV env;
854 	register struct tbl *vp, **vpp;
855 	register int i;
856 
857 	XPinit(env, 64);
858 	for (l = e->loc; l != NULL; l = l->next)
859 		for (vpp = l->vars.tbls, i = l->vars.size; --i >= 0; )
860 			if ((vp = *vpp++) != NULL
861 			    && (vp->flag&(ISSET|EXPORT)) == (ISSET|EXPORT)) {
862 				register struct block *l2;
863 				register struct tbl *vp2;
864 				unsigned h = hash(vp->name);
865 
866 				/* unexport any redefined instances */
867 				for (l2 = l->next; l2 != NULL; l2 = l2->next) {
868 					vp2 = tsearch(&l2->vars, vp->name, h);
869 					if (vp2 != NULL)
870 						vp2->flag &= ~EXPORT;
871 				}
872 				if ((vp->flag&INTEGER)) {
873 					/* integer to string */
874 					char *val;
875 					val = str_val(vp);
876 					vp->flag &= ~(INTEGER|RDONLY);
877 					/* setstr can't fail here */
878 					setstr(vp, val, KSH_RETURN_ERROR);
879 				}
880 				XPput(env, vp->val.s);
881 			}
882 	XPput(env, NULL);
883 	return (char **) XPclose(env);
884 }
885 
886 /*
887  * Called after a fork in parent to bump the random number generator.
888  * Done to ensure children will not get the same random number sequence
889  * if the parent doesn't use $RANDOM.
890  */
891 void
892 change_random()
893 {
894     rand();
895 }
896 
897 /*
898  * handle special variables with side effects - PATH, SECONDS.
899  */
900 
901 /* Test if name is a special parameter */
902 static int
903 special(name)
904 	register const char * name;
905 {
906 	register struct tbl *tp;
907 
908 	tp = tsearch(&specials, name, hash(name));
909 	return tp && (tp->flag & ISSET) ? tp->type : V_NONE;
910 }
911 
912 /* Make a variable non-special */
913 static void
914 unspecial(name)
915 	register const char * name;
916 {
917 	register struct tbl *tp;
918 
919 	tp = tsearch(&specials, name, hash(name));
920 	if (tp)
921 		tdelete(tp);
922 }
923 
924 #ifdef KSH
925 static	time_t	seconds;		/* time SECONDS last set */
926 #endif /* KSH */
927 static	int	user_lineno;		/* what user set $LINENO to */
928 
929 static void
930 getspec(vp)
931 	register struct tbl *vp;
932 {
933 	switch (special(vp->name)) {
934 #ifdef KSH
935 	  case V_SECONDS:
936 		vp->flag &= ~SPECIAL;
937 		/* On start up the value of SECONDS is used before seconds
938 		 * has been set - don't do anything in this case
939 		 * (see initcoms[] in main.c).
940 		 */
941 		if (vp->flag & ISSET)
942 			setint(vp, (long) (time((time_t *)0) - seconds));
943 		vp->flag |= SPECIAL;
944 		break;
945 	  case V_RANDOM:
946 		vp->flag &= ~SPECIAL;
947 		setint(vp, (long) (rand() & 0x7fff));
948 		vp->flag |= SPECIAL;
949 		break;
950 #endif /* KSH */
951 #ifdef HISTORY
952 	  case V_HISTSIZE:
953 		vp->flag &= ~SPECIAL;
954 		setint(vp, (long) histsize);
955 		vp->flag |= SPECIAL;
956 		break;
957 #endif /* HISTORY */
958 	  case V_OPTIND:
959 		vp->flag &= ~SPECIAL;
960 		setint(vp, (long) user_opt.uoptind);
961 		vp->flag |= SPECIAL;
962 		break;
963 	  case V_LINENO:
964 		vp->flag &= ~SPECIAL;
965 		setint(vp, (long) current_lineno + user_lineno);
966 		vp->flag |= SPECIAL;
967 		break;
968 	}
969 }
970 
971 static void
972 setspec(vp)
973 	register struct tbl *vp;
974 {
975 	char *s;
976 
977 	switch (special(vp->name)) {
978 	  case V_PATH:
979 		if (path)
980 			afree(path, APERM);
981 		path = str_save(str_val(vp), APERM);
982 		flushcom(1);	/* clear tracked aliases */
983 		break;
984 	  case V_IFS:
985 		setctypes(s = str_val(vp), C_IFS);
986 		ifs0 = *s;
987 		break;
988 	  case V_OPTIND:
989 		vp->flag &= ~SPECIAL;
990 		getopts_reset((int) intval(vp));
991 		vp->flag |= SPECIAL;
992 		break;
993 	  case V_POSIXLY_CORRECT:
994 		change_flag(FPOSIX, OF_SPECIAL, 1);
995 		break;
996 	  case V_TMPDIR:
997 		if (tmpdir) {
998 			afree(tmpdir, APERM);
999 			tmpdir = (char *) 0;
1000 		}
1001 		/* Use tmpdir iff it is an absolute path, is writable and
1002 		 * searchable and is a directory...
1003 		 */
1004 		{
1005 			struct stat statb;
1006 			s = str_val(vp);
1007 			if (ISABSPATH(s) && eaccess(s, W_OK|X_OK) == 0
1008 			    && stat(s, &statb) == 0 && S_ISDIR(statb.st_mode))
1009 				tmpdir = str_save(s, APERM);
1010 		}
1011 		break;
1012 #ifdef HISTORY
1013 	  case V_HISTSIZE:
1014 		vp->flag &= ~SPECIAL;
1015 		sethistsize((int) intval(vp));
1016 		vp->flag |= SPECIAL;
1017 		break;
1018 	  case V_HISTFILE:
1019 		sethistfile(str_val(vp));
1020 		break;
1021 #endif /* HISTORY */
1022 #ifdef EDIT
1023 	  case V_VISUAL:
1024 		set_editmode(str_val(vp));
1025 		break;
1026 	  case V_EDITOR:
1027 		if (!(global("VISUAL")->flag & ISSET))
1028 			set_editmode(str_val(vp));
1029 		break;
1030 	  case V_COLUMNS:
1031 		if ((x_cols = intval(vp)) <= MIN_COLS)
1032 			x_cols = MIN_COLS;
1033 		break;
1034 #endif /* EDIT */
1035 #ifdef KSH
1036 	  case V_MAIL:
1037 		mbset(str_val(vp));
1038 		break;
1039 	  case V_MAILPATH:
1040 		mpset(str_val(vp));
1041 		break;
1042 	  case V_MAILCHECK:
1043 		vp->flag &= ~SPECIAL;
1044 		mcset(intval(vp));
1045 		vp->flag |= SPECIAL;
1046 		break;
1047 	  case V_RANDOM:
1048 		vp->flag &= ~SPECIAL;
1049 		srand((unsigned int)intval(vp));
1050 		vp->flag |= SPECIAL;
1051 		break;
1052 	  case V_SECONDS:
1053 		vp->flag &= ~SPECIAL;
1054 		seconds = time((time_t*) 0) - intval(vp);
1055 		vp->flag |= SPECIAL;
1056 		break;
1057 	  case V_TMOUT:
1058 		/* at&t ksh seems to do this (only listen if integer) */
1059 		if (vp->flag & INTEGER)
1060 			ksh_tmout = vp->val.i >= 0 ? vp->val.i : 0;
1061 		break;
1062 #endif /* KSH */
1063 	  case V_LINENO:
1064 		vp->flag &= ~SPECIAL;
1065 		/* The -1 is because line numbering starts at 1. */
1066 		user_lineno = (unsigned int) intval(vp) - current_lineno - 1;
1067 		vp->flag |= SPECIAL;
1068 		break;
1069 	}
1070 }
1071 
1072 static void
1073 unsetspec(vp)
1074 	register struct tbl *vp;
1075 {
1076 	switch (special(vp->name)) {
1077 	  case V_PATH:
1078 		if (path)
1079 			afree(path, APERM);
1080 		path = str_save(def_path, APERM);
1081 		flushcom(1);	/* clear tracked aliases */
1082 		break;
1083 	  case V_IFS:
1084 		setctypes(" \t\n", C_IFS);
1085 		ifs0 = ' ';
1086 		break;
1087 	  case V_TMPDIR:
1088 		/* should not become unspecial */
1089 		if (tmpdir) {
1090 			afree(tmpdir, APERM);
1091 			tmpdir = (char *) 0;
1092 		}
1093 		break;
1094 #ifdef KSH
1095 	  case V_MAIL:
1096 		mbset((char *) 0);
1097 		break;
1098 	  case V_MAILPATH:
1099 		mpset((char *) 0);
1100 		break;
1101 #endif /* KSH */
1102 
1103 	  case V_LINENO:
1104 #ifdef KSH
1105 	  case V_MAILCHECK:	/* at&t ksh leaves previous value in place */
1106 	  case V_RANDOM:
1107 	  case V_SECONDS:
1108 	  case V_TMOUT:		/* at&t ksh leaves previous value in place */
1109 #endif /* KSH */
1110 		unspecial(vp->name);
1111 		break;
1112 
1113 	  /* at&t ksh man page says OPTIND, OPTARG and _ lose special meaning,
1114 	   * but OPTARG does not (still set by getopts) and _ is also still
1115 	   * set in various places.
1116 	   * Don't know what at&t does for:
1117 	   *		MAIL, MAILPATH, HISTSIZE, HISTFILE,
1118 	   * Unsetting these in at&t ksh does not loose the `specialness':
1119 	   *    no effect: IFS, COLUMNS, PATH, TMPDIR,
1120 	   *		VISUAL, EDITOR,
1121 	   * pdkshisms: no effect:
1122 	   *		POSIXLY_CORRECT (use set +o posix instead)
1123 	   */
1124 	}
1125 }
1126 
1127 /*
1128  * Search for (and possibly create) a table entry starting with
1129  * vp, indexed by val.
1130  */
1131 static struct tbl *
1132 arraysearch(vp, val)
1133 	struct tbl *vp;
1134 	int val;
1135 {
1136 	struct tbl *prev, *curr, *new;
1137 
1138 	vp->flag |= ARRAY|DEFINED;
1139 
1140 	/* The table entry is always [0] */
1141 	if (val == 0) {
1142 		vp->index = 0;
1143 		return vp;
1144 	}
1145 	prev = vp;
1146 	curr = vp->u.array;
1147 	while (curr && curr->index < val) {
1148 		prev = curr;
1149 		curr = curr->u.array;
1150 	}
1151 	if (curr && curr->index == val) {
1152 		if (curr->flag&ISSET)
1153 			return curr;
1154 		else
1155 			new = curr;
1156 	} else
1157 		new = (struct tbl *)alloc(sizeof(struct tbl)+strlen(vp->name)+1, vp->areap);
1158 	strcpy(new->name, vp->name);
1159 	new->flag = vp->flag & ~(ALLOC|DEFINED|ISSET|SPECIAL);
1160 	new->type = vp->type;
1161 	new->areap = vp->areap;
1162 	new->u2.field = vp->u2.field;
1163 	new->index = val;
1164 	if (curr != new) {		/* not reusing old array entry */
1165 		prev->u.array = new;
1166 		new->u.array = curr;
1167 	}
1168 	return new;
1169 }
1170 
1171 /* Return the length of an array reference (eg, [1+2]) - cp is assumed
1172  * to point to the open bracket.  Returns 0 if there is no matching closing
1173  * bracket.
1174  */
1175 int
1176 array_ref_len(cp)
1177 	const char *cp;
1178 {
1179 	const char *s = cp;
1180 	int c;
1181 	int depth = 0;
1182 
1183 	while ((c = *s++) && (c != ']' || --depth))
1184 		if (c == '[')
1185 			depth++;
1186 	if (!c)
1187 		return 0;
1188 	return s - cp;
1189 }
1190 
1191 /*
1192  * Make a copy of the base of an array name
1193  */
1194 char *
1195 arrayname(str)
1196 	const char *str;
1197 {
1198 	const char *p;
1199 
1200 	if ((p = strchr(str, '[')) == 0)
1201 		/* Shouldn't happen, but why worry? */
1202 		return (char *) str;
1203 
1204 	return str_nsave(str, p - str, ATEMP);
1205 }
1206 
1207 /* Set (or overwrite, if !reset) the array variable var to the values in vals.
1208  */
1209 void
1210 set_array(var, reset, vals)
1211 	const char *var;
1212 	int reset;
1213 	char **vals;
1214 {
1215 	struct tbl *vp, *vq;
1216 	int i;
1217 
1218 	/* to get local array, use "typeset foo; set -A foo" */
1219 	vp = global(var);
1220 
1221 	/* Note: at&t ksh allows set -A but not set +A of a read-only var */
1222 	if ((vp->flag&RDONLY))
1223 		errorf("%s: is read only", var);
1224 	/* This code is quite non-optimal */
1225 	if (reset > 0)
1226 		/* trash existing values and attributes */
1227 		unset(vp, 0);
1228 	/* todo: would be nice for assignment to completely succeed or
1229 	 * completely fail.  Only really effects integer arrays:
1230 	 * evaluation of some of vals[] may fail...
1231 	 */
1232 	for (i = 0; vals[i]; i++) {
1233 		vq = arraysearch(vp, i);
1234 		/* would be nice to deal with errors here... (see above) */
1235 		setstr(vq, vals[i], KSH_RETURN_ERROR);
1236 	}
1237 }
1238