xref: /openbsd-src/bin/ksh/var.c (revision b2ea75c1b17e1a9a339660e7ed45cd24946b230e) 
1 /*	$OpenBSD: var.c,v 1.11 2000/11/21 23:12:04 millert 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 
29 /*
30  * create a new block for function calls and simple commands
31  * assume caller has allocated and set up e->loc
32  */
33 void
34 newblock()
35 {
36 	register struct block *l;
37 	static char *const empty[] = {null};
38 
39 	l = (struct block *) alloc(sizeof(struct block), ATEMP);
40 	l->flags = 0;
41 	ainit(&l->area); /* todo: could use e->area (l->area => l->areap) */
42 	if (!e->loc) {
43 		l->argc = 0;
44 		l->argv = (char **) empty;
45 	} else {
46 		l->argc = e->loc->argc;
47 		l->argv = e->loc->argv;
48 	}
49 	l->exit = l->error = NULL;
50 	tinit(&l->vars, &l->area, 0);
51 	tinit(&l->funs, &l->area, 0);
52 	l->next = e->loc;
53 	e->loc = l;
54 }
55 
56 /*
57  * pop a block handling special variables
58  */
59 void
60 popblock()
61 {
62 	register struct block *l = e->loc;
63 	register struct tbl *vp, **vpp = l->vars.tbls, *vq;
64 	register int i;
65 
66 	e->loc = l->next;	/* pop block */
67 	for (i = l->vars.size; --i >= 0; )
68 		if ((vp = *vpp++) != NULL && (vp->flag&SPECIAL)) {
69 			if ((vq = global(vp->name))->flag & ISSET)
70 				setspec(vq);
71 			else
72 				unsetspec(vq);
73 		}
74 	if (l->flags & BF_DOGETOPTS)
75 		user_opt = l->getopts_state;
76 	afreeall(&l->area);
77 	afree(l, ATEMP);
78 }
79 
80 /* called by main() to initialize variable data structures */
81 void
82 initvar()
83 {
84 	static const struct {
85 		const char *name;
86 		int v;
87 	} names[] = {
88 			{ "COLUMNS",		V_COLUMNS },
89 			{ "IFS",		V_IFS },
90 			{ "OPTIND",		V_OPTIND },
91 			{ "PATH",		V_PATH },
92 			{ "POSIXLY_CORRECT",	V_POSIXLY_CORRECT },
93 			{ "TMPDIR",		V_TMPDIR },
94 #ifdef HISTORY
95 			{ "HISTFILE",		V_HISTFILE },
96 			{ "HISTSIZE",		V_HISTSIZE },
97 #endif /* HISTORY */
98 #ifdef EDIT
99 			{ "EDITOR",		V_EDITOR },
100 			{ "VISUAL",		V_VISUAL },
101 #endif /* EDIT */
102 #ifdef KSH
103 			{ "MAIL",		V_MAIL },
104 			{ "MAILCHECK",		V_MAILCHECK },
105 			{ "MAILPATH",		V_MAILPATH },
106 			{ "RANDOM",		V_RANDOM },
107 			{ "SECONDS",		V_SECONDS },
108 			{ "TMOUT",		V_TMOUT },
109 #endif /* KSH */
110 			{ "LINENO",		V_LINENO },
111 			{ (char *) 0,	0 }
112 		};
113 	int i;
114 	struct tbl *tp;
115 
116 	tinit(&specials, APERM, 32); /* must be 2^n (currently 17 specials) */
117 	for (i = 0; names[i].name; i++) {
118 		tp = tenter(&specials, names[i].name, hash(names[i].name));
119 		tp->flag = DEFINED|ISSET;
120 		tp->type = names[i].v;
121 	}
122 }
123 
124 /* Used to calculate an array index for global()/local().  Sets *arrayp to
125  * non-zero if this is an array, sets *valp to the array index, returns
126  * the basename of the array.
127  */
128 const char *
129 array_index_calc(n, arrayp, valp)
130 	const char *n;
131 	bool_t *arrayp;
132 	int *valp;
133 {
134 	const char *p;
135 	int len;
136 
137 	*arrayp = FALSE;
138 	p = skip_varname(n, FALSE);
139 	if (p != n && *p == '[' && (len = array_ref_len(p))) {
140 		char *sub, *tmp;
141 		long rval;
142 
143 		/* Calculate the value of the subscript */
144 		*arrayp = TRUE;
145 		tmp = str_nsave(p+1, len-2, ATEMP);
146 		sub = substitute(tmp, 0);
147 		afree(tmp, ATEMP);
148 		n = str_nsave(n, p - n, ATEMP);
149 		evaluate(sub, &rval, KSH_UNWIND_ERROR);
150 		if (rval < 0 || rval > ARRAYMAX)
151 			errorf("%s: subscript out of range", n);
152 		*valp = rval;
153 		afree(sub, ATEMP);
154 	}
155 	return n;
156 }
157 
158 /*
159  * Search for variable, if not found create globally.
160  */
161 struct tbl *
162 global(n)
163 	register const char *n;
164 {
165 	register struct block *l = e->loc;
166 	register struct tbl *vp;
167 	register int c;
168 	unsigned h;
169 	bool_t	 array;
170 	int	 val;
171 
172 	/* Check to see if this is an array */
173 	n = array_index_calc(n, &array, &val);
174 	h = hash(n);
175 	c = n[0];
176 	if (!letter(c)) {
177 		if (array)
178 			errorf("bad substitution");
179 		vp = &vtemp;
180 		vp->flag = DEFINED;
181 		vp->type = 0;
182 		vp->areap = ATEMP;
183 		*vp->name = c;
184 		if (digit(c)) {
185 			for (c = 0; digit(*n); n++)
186 				c = c*10 + *n-'0';
187 			if (c <= l->argc)
188 				/* setstr can't fail here */
189 				setstr(vp, l->argv[c], KSH_RETURN_ERROR);
190 			vp->flag |= RDONLY;
191 			return vp;
192 		}
193 		vp->flag |= RDONLY;
194 		if (n[1] != '\0')
195 			return vp;
196 		vp->flag |= ISSET|INTEGER;
197 		switch (c) {
198 		  case '$':
199 			vp->val.i = kshpid;
200 			break;
201 		  case '!':
202 			/* If no job, expand to nothing */
203 			if ((vp->val.i = j_async()) == 0)
204 				vp->flag &= ~(ISSET|INTEGER);
205 			break;
206 		  case '?':
207 			vp->val.i = exstat;
208 			break;
209 		  case '#':
210 			vp->val.i = l->argc;
211 			break;
212 		  case '-':
213 			vp->flag &= ~INTEGER;
214 			vp->val.s = getoptions();
215 			break;
216 		  default:
217 			vp->flag &= ~(ISSET|INTEGER);
218 		}
219 		return vp;
220 	}
221 	for (l = e->loc; ; l = l->next) {
222 		vp = tsearch(&l->vars, n, h);
223 		if (vp != NULL) {
224 			if (array)
225 				return arraysearch(vp, val);
226 			else
227 				return vp;
228 		}
229 		if (l->next == NULL)
230 			break;
231 	}
232 	vp = tenter(&l->vars, n, h);
233 	if (array)
234 		vp = arraysearch(vp, val);
235 	vp->flag |= DEFINED;
236 	if (special(n))
237 		vp->flag |= SPECIAL;
238 	return vp;
239 }
240 
241 /*
242  * Search for local variable, if not found create locally.
243  */
244 struct tbl *
245 local(n, copy)
246 	register const char *n;
247 	bool_t copy;
248 {
249 	register struct block *l = e->loc;
250 	register struct tbl *vp;
251 	unsigned h;
252 	bool_t	 array;
253 	int	 val;
254 
255 	/* Check to see if this is an array */
256 	n = array_index_calc(n, &array, &val);
257 	h = hash(n);
258 	if (!letter(*n)) {
259 		vp = &vtemp;
260 		vp->flag = DEFINED|RDONLY;
261 		vp->type = 0;
262 		vp->areap = ATEMP;
263 		return vp;
264 	}
265 	vp = tenter(&l->vars, n, h);
266 	if (copy && !(vp->flag & DEFINED)) {
267 		struct block *ll = l;
268 		struct tbl *vq = (struct tbl *) 0;
269 
270 		while ((ll = ll->next) && !(vq = tsearch(&ll->vars, n, h)))
271 			;
272 		if (vq) {
273 			vp->flag |= vq->flag & (EXPORT|INTEGER|RDONLY
274 						|LJUST|RJUST|ZEROFIL
275 						|LCASEV|UCASEV_AL|INT_U|INT_L);
276 			if (vq->flag & INTEGER)
277 				vp->type = vq->type;
278 			vp->u2.field = vq->u2.field;
279 		}
280 	}
281 	if (array)
282 		vp = arraysearch(vp, val);
283 	vp->flag |= DEFINED;
284 	if (special(n))
285 		vp->flag |= SPECIAL;
286 	return vp;
287 }
288 
289 /* get variable string value */
290 char *
291 str_val(vp)
292 	register struct tbl *vp;
293 {
294 	char *s;
295 
296 	if ((vp->flag&SPECIAL))
297 		getspec(vp);
298 	if (!(vp->flag&ISSET))
299 		s = null;		/* special to dollar() */
300 	else if (!(vp->flag&INTEGER))	/* string source */
301 		s = vp->val.s + vp->type;
302 	else {				/* integer source */
303 		/* worst case number length is when base=2, so use BITS(long) */
304 			     /* minus base #     number    null */
305 		static char strbuf[1 + 2 + 1 + BITS(long) + 1];
306 		const char *digits = (vp->flag & UCASEV_AL) ?
307 				  "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
308 				: "0123456789abcdefghijklmnopqrstuvwxyz";
309 		register unsigned long n;
310 		register int base;
311 
312 		s = strbuf + sizeof(strbuf);
313 		if (vp->flag & INT_U)
314 			n = (unsigned long) vp->val.i;
315 		else
316 			n = (vp->val.i < 0) ? -vp->val.i : vp->val.i;
317 		base = (vp->type == 0) ? 10 : vp->type;
318 
319 		*--s = '\0';
320 		do {
321 			*--s = digits[n % base];
322 			n /= base;
323 		} while (n != 0);
324 		if (base != 10) {
325 			*--s = '#';
326 			*--s = digits[base % 10];
327 			if (base >= 10)
328 				*--s = digits[base / 10];
329 		}
330 		if (!(vp->flag & INT_U) && vp->val.i < 0)
331 			*--s = '-';
332 		if (vp->flag & (RJUST|LJUST)) /* case already dealt with */
333 			s = formatstr(vp, s);
334 	}
335 	return s;
336 }
337 
338 /* get variable integer value, with error checking */
339 long
340 intval(vp)
341 	register struct tbl *vp;
342 {
343 	long num;
344 	int base;
345 
346 	base = getint(vp, &num);
347 	if (base == -1)
348 		/* XXX check calls - is error here ok by POSIX? */
349 		errorf("%s: bad number", str_val(vp));
350 	return num;
351 }
352 
353 /* set variable to string value */
354 int
355 setstr(vq, s, error_ok)
356 	register struct tbl *vq;
357 	const char *s;
358 	int error_ok;
359 {
360 	int no_ro_check = error_ok & 0x4;
361 	error_ok &= ~0x4;
362 	if ((vq->flag & RDONLY) && !no_ro_check) {
363 		warningf(TRUE, "%s: is read only", vq->name);
364 		if (!error_ok)
365 			errorf(null);
366 		return 0;
367 	}
368 	if (!(vq->flag&INTEGER)) { /* string dest */
369 		if ((vq->flag&ALLOC)) {
370 			/* debugging */
371 			if (s >= vq->val.s
372 			    && s <= vq->val.s + strlen(vq->val.s))
373 				internal_errorf(TRUE,
374 				    "setstr: %s=%s: assigning to self",
375 				    vq->name, s);
376 			afree((void*)vq->val.s, vq->areap);
377 		}
378 		vq->flag &= ~(ISSET|ALLOC);
379 		vq->type = 0;
380 		if (s && (vq->flag & (UCASEV_AL|LCASEV|LJUST|RJUST)))
381 			s = formatstr(vq, s);
382 		if ((vq->flag&EXPORT))
383 			export(vq, s);
384 		else {
385 			vq->val.s = str_save(s, vq->areap);
386 			if (vq->val.s)		/* <sjg> don't lie */
387 				vq->flag |= ALLOC;
388 		}
389 	} else			/* integer dest */
390 		if (!v_evaluate(vq, s, error_ok))
391 			return 0;
392 	vq->flag |= ISSET;
393 	if ((vq->flag&SPECIAL))
394 		setspec(vq);
395 	return 1;
396 }
397 
398 /* set variable to integer */
399 void
400 setint(vq, n)
401 	register struct tbl *vq;
402 	long n;
403 {
404 	if (!(vq->flag&INTEGER)) {
405 		register struct tbl *vp = &vtemp;
406 		vp->flag = (ISSET|INTEGER);
407 		vp->type = 0;
408 		vp->areap = ATEMP;
409 		vp->val.i = n;
410 		/* setstr can't fail here */
411 		setstr(vq, str_val(vp), KSH_RETURN_ERROR);
412 	} else
413 		vq->val.i = n;
414 	vq->flag |= ISSET;
415 	if ((vq->flag&SPECIAL))
416 		setspec(vq);
417 }
418 
419 int
420 getint(vp, nump)
421 	struct tbl *vp;
422 	long *nump;
423 {
424 	register char *s;
425 	register int c;
426 	int base, neg;
427 	int have_base = 0;
428 	long num;
429 
430 	if (vp->flag&SPECIAL)
431 		getspec(vp);
432 	/* XXX is it possible for ISSET to be set and val.s to be 0? */
433 	if (!(vp->flag&ISSET) || (!(vp->flag&INTEGER) && vp->val.s == NULL))
434 		return -1;
435 	if (vp->flag&INTEGER) {
436 		*nump = vp->val.i;
437 		return vp->type;
438 	}
439 	s = vp->val.s + vp->type;
440 	if (s == NULL)	/* redundent given initial test */
441 		s = null;
442 	base = 10;
443 	num = 0;
444 	neg = 0;
445 	for (c = *s++; c ; c = *s++) {
446 		if (c == '-') {
447 			neg++;
448 		} else if (c == '#') {
449 			base = (int) num;
450 			if (have_base || base < 2 || base > 36)
451 				return -1;
452 			num = 0;
453 			have_base = 1;
454 		} else if (letnum(c)) {
455 			if (isdigit(c))
456 				c -= '0';
457 			else if (islower(c))
458 				c -= 'a' - 10; /* todo: assumes ascii */
459 			else if (isupper(c))
460 				c -= 'A' - 10; /* todo: assumes ascii */
461 			else
462 				c = -1; /* _: force error */
463 			if (c < 0 || c >= base)
464 				return -1;
465 			num = num * base + c;
466 		} else
467 			return -1;
468 	}
469 	if (neg)
470 		num = -num;
471 	*nump = num;
472 	return base;
473 }
474 
475 /* convert variable vq to integer variable, setting its value from vp
476  * (vq and vp may be the same)
477  */
478 struct tbl *
479 setint_v(vq, vp)
480 	register struct tbl *vq, *vp;
481 {
482 	int base;
483 	long num;
484 
485 	if ((base = getint(vp, &num)) == -1)
486 		return NULL;
487 	if (!(vq->flag & INTEGER) && (vq->flag & ALLOC)) {
488 		vq->flag &= ~ALLOC;
489 		afree(vq->val.s, vq->areap);
490 	}
491 	vq->val.i = num;
492 	if (vq->type == 0) /* default base */
493 		vq->type = base;
494 	vq->flag |= ISSET|INTEGER;
495 	if (vq->flag&SPECIAL)
496 		setspec(vq);
497 	return vq;
498 }
499 
500 static char *
501 formatstr(vp, s)
502 	struct tbl *vp;
503 	const char *s;
504 {
505 	int olen, nlen;
506 	char *p, *q;
507 
508 	olen = strlen(s);
509 
510 	if (vp->flag & (RJUST|LJUST)) {
511 		if (!vp->u2.field)	/* default field width */
512 			vp->u2.field = olen;
513 		nlen = vp->u2.field;
514 	} else
515 		nlen = olen;
516 
517 	p = (char *) alloc(nlen + 1, ATEMP);
518 	if (vp->flag & (RJUST|LJUST)) {
519 		int slen;
520 
521 		if (vp->flag & RJUST) {
522 			const char *q = s + olen;
523 			/* strip trailing spaces (at&t ksh uses q[-1] == ' ') */
524 			while (q > s && isspace(q[-1]))
525 				--q;
526 			slen = q - s;
527 			if (slen > vp->u2.field) {
528 				s += slen - vp->u2.field;
529 				slen = vp->u2.field;
530 			}
531 			shf_snprintf(p, nlen + 1,
532 				((vp->flag & ZEROFIL) && digit(*s)) ?
533 					  "%0*s%.*s" : "%*s%.*s",
534 				vp->u2.field - slen, null, slen, s);
535 		} else {
536 			/* strip leading spaces/zeros */
537 			while (isspace(*s))
538 				s++;
539 			if (vp->flag & ZEROFIL)
540 				while (*s == '0')
541 					s++;
542 			shf_snprintf(p, nlen + 1, "%-*.*s",
543 				vp->u2.field, vp->u2.field, s);
544 		}
545 	} else
546 		memcpy(p, s, olen + 1);
547 
548 	if (vp->flag & UCASEV_AL) {
549 		for (q = p; *q; q++)
550 			if (islower(*q))
551 				*q = toupper(*q);
552 	} else if (vp->flag & LCASEV) {
553 		for (q = p; *q; q++)
554 			if (isupper(*q))
555 				*q = tolower(*q);
556 	}
557 
558 	return p;
559 }
560 
561 /*
562  * make vp->val.s be "name=value" for quick exporting.
563  */
564 static void
565 export(vp, val)
566 	register struct tbl *vp;
567 	const char *val;
568 {
569 	register char *xp;
570 	char *op = (vp->flag&ALLOC) ? vp->val.s : NULL;
571 	int namelen = strlen(vp->name);
572 	int vallen = strlen(val) + 1;
573 
574 	vp->flag |= ALLOC;
575 	xp = (char*)alloc(namelen + 1 + vallen, vp->areap);
576 	memcpy(vp->val.s = xp, vp->name, namelen);
577 	xp += namelen;
578 	*xp++ = '=';
579 	vp->type = xp - vp->val.s; /* offset to value */
580 	memcpy(xp, val, vallen);
581 	if (op != NULL)
582 		afree((void*)op, vp->areap);
583 }
584 
585 /*
586  * lookup variable (according to (set&LOCAL)),
587  * set its attributes (INTEGER, RDONLY, EXPORT, TRACE, LJUST, RJUST, ZEROFIL,
588  * LCASEV, UCASEV_AL), and optionally set its value if an assignment.
589  */
590 struct tbl *
591 typeset(var, set, clr, field, base)
592 	register const char *var;
593 	Tflag clr, set;
594 	int field, base;
595 {
596 	register struct tbl *vp;
597 	struct tbl *vpbase, *t;
598 	char *tvar;
599 	const char *val;
600 
601 	/* check for valid variable name, search for value */
602 	val = skip_varname(var, FALSE);
603 	if (val == var)
604 		return NULL;
605 	if (*val == '[') {
606 		int len;
607 
608 		len = array_ref_len(val);
609 		if (len == 0)
610 			return NULL;
611 		/* IMPORT is only used when the shell starts up and is
612 		 * setting up its environment.  Allow only simple array
613 		 * references at this time since parameter/command substitution
614 		 * is preformed on the [expression], which would be a major
615 		 * security hole.
616 		 */
617 		if (set & IMPORT) {
618 			int i;
619 			for (i = 1; i < len - 1; i++)
620 				if (!digit(val[i]))
621 					return NULL;
622 		}
623 		val += len;
624 	}
625 	if (*val == '=')
626 		tvar = str_nsave(var, val++ - var, ATEMP);
627 	else {
628 		/* Importing from original envirnment: must have an = */
629 		if (set & IMPORT)
630 			return NULL;
631 		tvar = (char *) var;
632 		val = NULL;
633 	}
634 
635 	/* Prevent typeset from creating a local PATH/ENV/SHELL */
636 	if (Flag(FRESTRICTED) && (strcmp(tvar, "PATH") == 0
637 				  || strcmp(tvar, "ENV") == 0
638 				  || strcmp(tvar, "SHELL") == 0))
639 		errorf("%s: restricted", tvar);
640 
641 	vp = (set&LOCAL) ? local(tvar, (set & LOCAL_COPY) ? TRUE : FALSE)
642 		: global(tvar);
643 	set &= ~(LOCAL|LOCAL_COPY);
644 
645 	vpbase = (vp->flag & ARRAY) ? global(arrayname(var)) : vp;
646 
647 	/* only allow export flag to be set.  at&t ksh allows any attribute to
648 	 * be changed, which means it can be truncated or modified
649 	 * (-L/-R/-Z/-i).
650 	 */
651 	if ((vpbase->flag&RDONLY)
652 	    && (val || clr || (set & ~EXPORT)))
653 		/* XXX check calls - is error here ok by POSIX? */
654 		errorf("%s: is read only", tvar);
655 	if (val)
656 		afree(tvar, ATEMP);
657 
658 	/* most calls are with set/clr == 0 */
659 	if (set | clr) {
660 		int ok = 1;
661 		/* XXX if x[0] isn't set, there will be problems: need to have
662 		 * one copy of attributes for arrays...
663 		 */
664 		for (t = vpbase; t; t = t->u.array) {
665 			int fake_assign;
666 			char UNINITIALIZED(*s);
667 			char UNINITIALIZED(*free_me);
668 
669 			fake_assign = (t->flag & ISSET) && (!val || t != vp)
670 				      && ((set & (UCASEV_AL|LCASEV|LJUST|RJUST|ZEROFIL))
671 					  || ((t->flag & INTEGER) && (clr & INTEGER))
672 					  || (!(t->flag & INTEGER) && (set & INTEGER)));
673 			if (fake_assign) {
674 				if (t->flag & INTEGER) {
675 					s = str_val(t);
676 					free_me = (char *) 0;
677 				} else {
678 					s = t->val.s + t->type;
679 					free_me = (t->flag & ALLOC) ? t->val.s
680 								  : (char *) 0;
681 				}
682 				t->flag &= ~ALLOC;
683 			}
684 			if (!(t->flag & INTEGER) && (set & INTEGER)) {
685 				t->type = 0;
686 				t->flag &= ~ALLOC;
687 			}
688 			t->flag = (t->flag | set) & ~clr;
689 			/* Don't change base if assignment is to be done,
690 			 * in case assignment fails.
691 			 */
692 			if ((set & INTEGER) && base > 0 && (!val || t != vp))
693 				t->type = base;
694 			if (set & (LJUST|RJUST|ZEROFIL))
695 				t->u2.field = field;
696 			if (fake_assign) {
697 				if (!setstr(t, s, KSH_RETURN_ERROR)) {
698 					/* Somewhat arbitrary action here:
699 					 * zap contents of varibale, but keep
700 					 * the flag settings.
701 					 */
702 					ok = 0;
703 					if (t->flag & INTEGER)
704 						t->flag &= ~ISSET;
705 					else {
706 						if (t->flag & ALLOC)
707 							afree((void*) t->val.s,
708 							      t->areap);
709 						t->flag &= ~(ISSET|ALLOC);
710 						t->type = 0;
711 					}
712 				}
713 				if (free_me)
714 					afree((void *) free_me, t->areap);
715 			}
716 		}
717 		if (!ok)
718 		    errorf(null);
719 	}
720 
721 	if (val != NULL) {
722 		if (vp->flag&INTEGER) {
723 			/* do not zero base before assignment */
724 			setstr(vp, val, KSH_UNWIND_ERROR | 0x4);
725 			/* Done after assignment to override default */
726 			if (base > 0)
727 				vp->type = base;
728 		} else
729 			/* setstr can't fail (readonly check already done) */
730 			setstr(vp, val, KSH_RETURN_ERROR | 0x4);
731 	}
732 
733 	/* only x[0] is ever exported, so use vpbase */
734 	if ((vpbase->flag&EXPORT) && !(vpbase->flag&INTEGER)
735 	    && vpbase->type == 0)
736 		export(vpbase, (vpbase->flag&ISSET) ? vpbase->val.s : null);
737 
738 	return vp;
739 }
740 
741 /* Unset a variable.  array_ref is set if there was an array reference in
742  * the name lookup (eg, x[2]).
743  */
744 void
745 unset(vp, array_ref)
746 	register struct tbl *vp;
747 	int array_ref;
748 {
749 	if (vp->flag & ALLOC)
750 		afree((void*)vp->val.s, vp->areap);
751 	if ((vp->flag & ARRAY) && !array_ref) {
752 		struct tbl *a, *tmp;
753 
754 		/* Free up entire array */
755 		for (a = vp->u.array; a; ) {
756 			tmp = a;
757 			a = a->u.array;
758 			if (tmp->flag & ALLOC)
759 				afree((void *) tmp->val.s, tmp->areap);
760 			afree(tmp, tmp->areap);
761 		}
762 		vp->u.array = (struct tbl *) 0;
763 	}
764 	/* If foo[0] is being unset, the remainder of the array is kept... */
765 	vp->flag &= SPECIAL | (array_ref ? ARRAY|DEFINED : 0);
766 	if (vp->flag & SPECIAL)
767 		unsetspec(vp);	/* responsible for `unspecial'ing var */
768 }
769 
770 /* return a pointer to the first char past a legal variable name (returns the
771  * argument if there is no legal name, returns * a pointer to the terminating
772  * null if whole string is legal).
773  */
774 char *
775 skip_varname(s, aok)
776 	const char *s;
777 	int aok;
778 {
779 	int alen;
780 
781 	if (s && letter(*s)) {
782 		while (*++s && letnum(*s))
783 			;
784 		if (aok && *s == '[' && (alen = array_ref_len(s)))
785 			s += alen;
786 	}
787 	return (char *) s;
788 }
789 
790 /* Return a pointer to the first character past any legal variable name.  */
791 char *
792 skip_wdvarname(s, aok)
793 	const char *s;
794 	int aok;	/* skip array de-reference? */
795 {
796 	if (s[0] == CHAR && letter(s[1])) {
797 		do
798 			s += 2;
799 		while (s[0] == CHAR && letnum(s[1]));
800 		if (aok && s[0] == CHAR && s[1] == '[') {
801 			/* skip possible array de-reference */
802 			const char *p = s;
803 			char c;
804 			int depth = 0;
805 
806 			while (1) {
807 				if (p[0] != CHAR)
808 					break;
809 				c = p[1];
810 				p += 2;
811 				if (c == '[')
812 					depth++;
813 				else if (c == ']' && --depth == 0) {
814 					s = p;
815 					break;
816 				}
817 			}
818 		}
819 	}
820 	return (char *) s;
821 }
822 
823 /* Check if coded string s is a variable name */
824 int
825 is_wdvarname(s, aok)
826 	const char *s;
827 	int aok;
828 {
829 	char *p = skip_wdvarname(s, aok);
830 
831 	return p != s && p[0] == EOS;
832 }
833 
834 /* Check if coded string s is a variable assignment */
835 int
836 is_wdvarassign(s)
837 	const char *s;
838 {
839 	char *p = skip_wdvarname(s, TRUE);
840 
841 	return p != s && p[0] == CHAR && p[1] == '=';
842 }
843 
844 /*
845  * Make the exported environment from the exported names in the dictionary.
846  */
847 char **
848 makenv()
849 {
850 	struct block *l = e->loc;
851 	XPtrV env;
852 	register struct tbl *vp, **vpp;
853 	register int i;
854 
855 	XPinit(env, 64);
856 	for (l = e->loc; l != NULL; l = l->next)
857 		for (vpp = l->vars.tbls, i = l->vars.size; --i >= 0; )
858 			if ((vp = *vpp++) != NULL
859 			    && (vp->flag&(ISSET|EXPORT)) == (ISSET|EXPORT)) {
860 				register struct block *l2;
861 				register struct tbl *vp2;
862 				unsigned h = hash(vp->name);
863 
864 				/* unexport any redefined instances */
865 				for (l2 = l->next; l2 != NULL; l2 = l2->next) {
866 					vp2 = tsearch(&l2->vars, vp->name, h);
867 					if (vp2 != NULL)
868 						vp2->flag &= ~EXPORT;
869 				}
870 				if ((vp->flag&INTEGER)) {
871 					/* integer to string */
872 					char *val;
873 					val = str_val(vp);
874 					vp->flag &= ~(INTEGER|RDONLY);
875 					/* setstr can't fail here */
876 					setstr(vp, val, KSH_RETURN_ERROR);
877 				}
878 				XPput(env, vp->val.s);
879 			}
880 	XPput(env, NULL);
881 	return (char **) XPclose(env);
882 }
883 
884 /*
885  * Called after a fork in parent to bump the random number generator.
886  * Done to ensure children will not get the same random number sequence
887  * if the parent doesn't use $RANDOM.
888  */
889 void
890 change_random()
891 {
892     rand();
893 }
894 
895 /*
896  * handle special variables with side effects - PATH, SECONDS.
897  */
898 
899 /* Test if name is a special parameter */
900 static int
901 special(name)
902 	register const char * name;
903 {
904 	register struct tbl *tp;
905 
906 	tp = tsearch(&specials, name, hash(name));
907 	return tp && (tp->flag & ISSET) ? tp->type : V_NONE;
908 }
909 
910 /* Make a variable non-special */
911 static void
912 unspecial(name)
913 	register const char * name;
914 {
915 	register struct tbl *tp;
916 
917 	tp = tsearch(&specials, name, hash(name));
918 	if (tp)
919 		tdelete(tp);
920 }
921 
922 #ifdef KSH
923 static	time_t	seconds;		/* time SECONDS last set */
924 #endif /* KSH */
925 static	int	user_lineno;		/* what user set $LINENO to */
926 
927 static void
928 getspec(vp)
929 	register struct tbl *vp;
930 {
931 	switch (special(vp->name)) {
932 #ifdef KSH
933 	  case V_SECONDS:
934 		vp->flag &= ~SPECIAL;
935 		/* On start up the value of SECONDS is used before seconds
936 		 * has been set - don't do anything in this case
937 		 * (see initcoms[] in main.c).
938 		 */
939 		if (vp->flag & ISSET)
940 			setint(vp, (long) (time((time_t *)0) - seconds));
941 		vp->flag |= SPECIAL;
942 		break;
943 	  case V_RANDOM:
944 		vp->flag &= ~SPECIAL;
945 		setint(vp, (long) (rand() & 0x7fff));
946 		vp->flag |= SPECIAL;
947 		break;
948 #endif /* KSH */
949 #ifdef HISTORY
950 	  case V_HISTSIZE:
951 		vp->flag &= ~SPECIAL;
952 		setint(vp, (long) histsize);
953 		vp->flag |= SPECIAL;
954 		break;
955 #endif /* HISTORY */
956 	  case V_OPTIND:
957 		vp->flag &= ~SPECIAL;
958 		setint(vp, (long) user_opt.uoptind);
959 		vp->flag |= SPECIAL;
960 		break;
961 	  case V_LINENO:
962 		vp->flag &= ~SPECIAL;
963 		setint(vp, (long) current_lineno + user_lineno);
964 		vp->flag |= SPECIAL;
965 		break;
966 	}
967 }
968 
969 static void
970 setspec(vp)
971 	register struct tbl *vp;
972 {
973 	char *s;
974 
975 	switch (special(vp->name)) {
976 	  case V_PATH:
977 		if (path)
978 			afree(path, APERM);
979 		path = str_save(str_val(vp), APERM);
980 		flushcom(1);	/* clear tracked aliases */
981 		break;
982 	  case V_IFS:
983 		setctypes(s = str_val(vp), C_IFS);
984 		ifs0 = *s;
985 		break;
986 	  case V_OPTIND:
987 		vp->flag &= ~SPECIAL;
988 		getopts_reset((int) intval(vp));
989 		vp->flag |= SPECIAL;
990 		break;
991 	  case V_POSIXLY_CORRECT:
992 		change_flag(FPOSIX, OF_SPECIAL, 1);
993 		break;
994 	  case V_TMPDIR:
995 		if (tmpdir) {
996 			afree(tmpdir, APERM);
997 			tmpdir = (char *) 0;
998 		}
999 		/* Use tmpdir iff it is an absolute path, is writable and
1000 		 * searchable and is a directory...
1001 		 */
1002 		{
1003 			struct stat statb;
1004 			s = str_val(vp);
1005 			if (ISABSPATH(s) && eaccess(s, W_OK|X_OK) == 0
1006 			    && stat(s, &statb) == 0 && S_ISDIR(statb.st_mode))
1007 				tmpdir = str_save(s, APERM);
1008 		}
1009 		break;
1010 #ifdef HISTORY
1011 	  case V_HISTSIZE:
1012 		vp->flag &= ~SPECIAL;
1013 		sethistsize((int) intval(vp));
1014 		vp->flag |= SPECIAL;
1015 		break;
1016 	  case V_HISTFILE:
1017 		sethistfile(str_val(vp));
1018 		break;
1019 #endif /* HISTORY */
1020 #ifdef EDIT
1021 	  case V_VISUAL:
1022 		set_editmode(str_val(vp));
1023 		break;
1024 	  case V_EDITOR:
1025 		if (!(global("VISUAL")->flag & ISSET))
1026 			set_editmode(str_val(vp));
1027 		break;
1028 	  case V_COLUMNS:
1029 		if ((x_cols = intval(vp)) <= MIN_COLS)
1030 			x_cols = MIN_COLS;
1031 		break;
1032 #endif /* EDIT */
1033 #ifdef KSH
1034 	  case V_MAIL:
1035 		mbset(str_val(vp));
1036 		break;
1037 	  case V_MAILPATH:
1038 		mpset(str_val(vp));
1039 		break;
1040 	  case V_MAILCHECK:
1041 		vp->flag &= ~SPECIAL;
1042 		mcset(intval(vp));
1043 		vp->flag |= SPECIAL;
1044 		break;
1045 	  case V_RANDOM:
1046 		vp->flag &= ~SPECIAL;
1047 		srand((unsigned int)intval(vp));
1048 		vp->flag |= SPECIAL;
1049 		break;
1050 	  case V_SECONDS:
1051 		vp->flag &= ~SPECIAL;
1052 		seconds = time((time_t*) 0) - intval(vp);
1053 		vp->flag |= SPECIAL;
1054 		break;
1055 	  case V_TMOUT:
1056 		/* at&t ksh seems to do this (only listen if integer) */
1057 		if (vp->flag & INTEGER)
1058 			ksh_tmout = vp->val.i >= 0 ? vp->val.i : 0;
1059 		break;
1060 #endif /* KSH */
1061 	  case V_LINENO:
1062 		vp->flag &= ~SPECIAL;
1063 		/* The -1 is because line numbering starts at 1. */
1064 		user_lineno = (unsigned int) intval(vp) - current_lineno - 1;
1065 		vp->flag |= SPECIAL;
1066 		break;
1067 	}
1068 }
1069 
1070 static void
1071 unsetspec(vp)
1072 	register struct tbl *vp;
1073 {
1074 	switch (special(vp->name)) {
1075 	  case V_PATH:
1076 		if (path)
1077 			afree(path, APERM);
1078 		path = str_save(def_path, APERM);
1079 		flushcom(1);	/* clear tracked aliases */
1080 		break;
1081 	  case V_IFS:
1082 		setctypes(" \t\n", C_IFS);
1083 		ifs0 = ' ';
1084 		break;
1085 	  case V_TMPDIR:
1086 		/* should not become unspecial */
1087 		if (tmpdir) {
1088 			afree(tmpdir, APERM);
1089 			tmpdir = (char *) 0;
1090 		}
1091 		break;
1092 #ifdef KSH
1093 	  case V_MAIL:
1094 		mbset((char *) 0);
1095 		break;
1096 	  case V_MAILPATH:
1097 		mpset((char *) 0);
1098 		break;
1099 #endif /* KSH */
1100 
1101 	  case V_LINENO:
1102 #ifdef KSH
1103 	  case V_MAILCHECK:	/* at&t ksh leaves previous value in place */
1104 	  case V_RANDOM:
1105 	  case V_SECONDS:
1106 	  case V_TMOUT:		/* at&t ksh leaves previous value in place */
1107 #endif /* KSH */
1108 		unspecial(vp->name);
1109 		break;
1110 
1111 	  /* at&t ksh man page says OPTIND, OPTARG and _ lose special meaning,
1112 	   * but OPTARG does not (still set by getopts) and _ is also still
1113 	   * set in various places.
1114 	   * Don't know what at&t does for:
1115 	   *		MAIL, MAILPATH, HISTSIZE, HISTFILE,
1116 	   * Unsetting these in at&t ksh does not loose the `specialness':
1117 	   *    no effect: IFS, COLUMNS, PATH, TMPDIR,
1118 	   *		VISUAL, EDITOR,
1119 	   * pdkshisms: no effect:
1120 	   *		POSIXLY_CORRECT (use set +o posix instead)
1121 	   */
1122 	}
1123 }
1124 
1125 /*
1126  * Search for (and possibly create) a table entry starting with
1127  * vp, indexed by val.
1128  */
1129 static struct tbl *
1130 arraysearch(vp, val)
1131 	struct tbl *vp;
1132 	int val;
1133 {
1134 	struct tbl *prev, *curr, *new;
1135 
1136 	vp->flag |= ARRAY|DEFINED;
1137 
1138 	/* The table entry is always [0] */
1139 	if (val == 0) {
1140 		vp->index = 0;
1141 		return vp;
1142 	}
1143 	prev = vp;
1144 	curr = vp->u.array;
1145 	while (curr && curr->index < val) {
1146 		prev = curr;
1147 		curr = curr->u.array;
1148 	}
1149 	if (curr && curr->index == val) {
1150 		if (curr->flag&ISSET)
1151 			return curr;
1152 		else
1153 			new = curr;
1154 	} else
1155 		new = (struct tbl *)alloc(sizeof(struct tbl)+strlen(vp->name)+1, vp->areap);
1156 	strcpy(new->name, vp->name);
1157 	new->flag = vp->flag & ~(ALLOC|DEFINED|ISSET|SPECIAL);
1158 	new->type = vp->type;
1159 	new->areap = vp->areap;
1160 	new->u2.field = vp->u2.field;
1161 	new->index = val;
1162 	if (curr != new) {		/* not reusing old array entry */
1163 		prev->u.array = new;
1164 		new->u.array = curr;
1165 	}
1166 	return new;
1167 }
1168 
1169 /* Return the length of an array reference (eg, [1+2]) - cp is assumed
1170  * to point to the open bracket.  Returns 0 if there is no matching closing
1171  * bracket.
1172  */
1173 int
1174 array_ref_len(cp)
1175 	const char *cp;
1176 {
1177 	const char *s = cp;
1178 	int c;
1179 	int depth = 0;
1180 
1181 	while ((c = *s++) && (c != ']' || --depth))
1182 		if (c == '[')
1183 			depth++;
1184 	if (!c)
1185 		return 0;
1186 	return s - cp;
1187 }
1188 
1189 /*
1190  * Make a copy of the base of an array name
1191  */
1192 char *
1193 arrayname(str)
1194 	const char *str;
1195 {
1196 	const char *p;
1197 
1198 	if ((p = strchr(str, '[')) == 0)
1199 		/* Shouldn't happen, but why worry? */
1200 		return (char *) str;
1201 
1202 	return str_nsave(str, p - str, ATEMP);
1203 }
1204 
1205 /* Set (or overwrite, if !reset) the array variable var to the values in vals.
1206  */
1207 void
1208 set_array(var, reset, vals)
1209 	const char *var;
1210 	int reset;
1211 	char **vals;
1212 {
1213 	struct tbl *vp, *vq;
1214 	int i;
1215 
1216 	/* to get local array, use "typeset foo; set -A foo" */
1217 	vp = global(var);
1218 
1219 	/* Note: at&t ksh allows set -A but not set +A of a read-only var */
1220 	if ((vp->flag&RDONLY))
1221 		errorf("%s: is read only", var);
1222 	/* This code is quite non-optimal */
1223 	if (reset > 0)
1224 		/* trash existing values and attributes */
1225 		unset(vp, 0);
1226 	/* todo: would be nice for assignment to completely succeed or
1227 	 * completely fail.  Only really effects integer arrays:
1228 	 * evaluation of some of vals[] may fail...
1229 	 */
1230 	for (i = 0; vals[i]; i++) {
1231 		vq = arraysearch(vp, i);
1232 		/* would be nice to deal with errors here... (see above) */
1233 		setstr(vq, vals[i], KSH_RETURN_ERROR);
1234 	}
1235 }
1236