1/*	$NetBSD: var.c,v 1.17 2011/10/16 17:12:11 joerg Exp $	*/
2
3#include <sys/cdefs.h>
4
5#ifndef lint
6__RCSID("$NetBSD: var.c,v 1.17 2011/10/16 17:12:11 joerg 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 */
25static	struct tbl vtemp;
26static	struct table specials;
27static char	*formatstr	ARGS((struct tbl *vp, const char *s));
28static void	export		ARGS((struct tbl *vp, const char *val));
29static int	special		ARGS((const char *name));
30static void	unspecial	ARGS((const char *name));
31static void	getspec		ARGS((struct tbl *vp));
32static void	setspec		ARGS((struct tbl *vp));
33static void	unsetspec	ARGS((struct tbl *vp));
34static 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 */
40void
41newblock()
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 */
66void
67popblock()
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 */
89void
90initvar()
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 */
136const char *array_index_calc(const char *n, bool_t *arrayp, int *valp);
137
138const char *
139array_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 */
171struct tbl *
172global(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 */
254struct tbl *
255local(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 */
300char *
301str_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			(void)strlcpy(strbuf, s, sizeof(strbuf));
345			afree(s, ATEMP);
346			s = strbuf;
347		}
348	}
349	return s;
350}
351
352/* get variable integer value, with error checking */
353long
354intval(vp)
355	register struct tbl *vp;
356{
357	long num;
358	int base;
359
360	base = getint(vp, &num);
361	if (base == -1)
362		/* XXX check calls - is error here ok by POSIX? */
363		errorf("%s: bad number", str_val(vp));
364	return num;
365}
366
367/* set variable to string value */
368int
369setstr(vq, s, error_ok)
370	register struct tbl *vq;
371	const char *s;
372	int error_ok;
373{
374	char *fs = NULL;
375	int no_ro_check = error_ok & 0x4;
376	error_ok &= ~0x4;
377	if ((vq->flag & RDONLY) && !no_ro_check) {
378		warningf(TRUE, "%s: is read only", vq->name);
379		if (!error_ok)
380			errorf("%s", null);
381		return 0;
382	}
383	if (!(vq->flag&INTEGER)) { /* string dest */
384		if ((vq->flag&ALLOC)) {
385			/* debugging */
386			if (s >= vq->val.s
387			    && s <= vq->val.s + strlen(vq->val.s))
388				internal_errorf(TRUE,
389				    "setstr: %s=%s: assigning to self",
390				    vq->name, s);
391			afree((void*)vq->val.s, vq->areap);
392		}
393		vq->flag &= ~(ISSET|ALLOC);
394		vq->type = 0;
395		if (s && (vq->flag & (UCASEV_AL|LCASEV|LJUST|RJUST)))
396			s = fs = formatstr(vq, s);
397		if ((vq->flag&EXPORT))
398			export(vq, s);
399		else {
400			vq->val.s = str_save(s, vq->areap);
401			vq->flag |= ALLOC;
402		}
403	} else			/* integer dest */
404		if (!v_evaluate(vq, s, error_ok))
405			return 0;
406	vq->flag |= ISSET;
407	if ((vq->flag&SPECIAL))
408		setspec(vq);
409	if (fs)
410		afree(fs, ATEMP);
411	return 1;
412}
413
414/* set variable to integer */
415void
416setint(vq, n)
417	register struct tbl *vq;
418	long n;
419{
420	if (!(vq->flag&INTEGER)) {
421		register struct tbl *vp = &vtemp;
422		vp->flag = (ISSET|INTEGER);
423		vp->type = 0;
424		vp->areap = ATEMP;
425		vp->val.i = n;
426		/* setstr can't fail here */
427		setstr(vq, str_val(vp), KSH_RETURN_ERROR);
428	} else
429		vq->val.i = n;
430	vq->flag |= ISSET;
431	if ((vq->flag&SPECIAL))
432		setspec(vq);
433}
434
435int
436getint(vp, nump)
437	struct tbl *vp;
438	long *nump;
439{
440	register char *s;
441	register int c;
442	int base, neg;
443	int have_base = 0;
444	long num;
445
446	if (vp->flag&SPECIAL)
447		getspec(vp);
448	/* XXX is it possible for ISSET to be set and val.s to be 0? */
449	if (!(vp->flag&ISSET) || (!(vp->flag&INTEGER) && vp->val.s == NULL))
450		return -1;
451	if (vp->flag&INTEGER) {
452		*nump = vp->val.i;
453		return vp->type;
454	}
455	s = vp->val.s + vp->type;
456	if (s == NULL)	/* redundant given initial test */
457		s = null;
458	base = 10;
459	num = 0;
460	neg = 0;
461	if (*s == '-') {
462		neg = 1;
463		s++;
464	}
465	if (s[0] == '0' && s[1] == 'x') {
466		base = 16;
467		have_base = 1;
468		s += 2;
469	}
470	for (c = (unsigned char)*s++; c ; c = (unsigned char)*s++) {
471		if (c == '#') {
472			base = (int) num;
473			if (have_base || base < 2 || base > 36)
474				return -1;
475			num = 0;
476			have_base = 1;
477		} else if (letnum(c)) {
478			if (isdigit(c))
479				c -= '0';
480			else if (islower(c))
481				c -= 'a' - 10; /* todo: assumes ascii */
482			else if (isupper(c))
483				c -= 'A' - 10; /* todo: assumes ascii */
484			else
485				c = -1; /* _: force error */
486			if (c < 0 || c >= base)
487				return -1;
488			num = num * base + c;
489		} else
490			return -1;
491	}
492	if (neg)
493		num = -num;
494	*nump = num;
495	return base;
496}
497
498/* convert variable vq to integer variable, setting its value from vp
499 * (vq and vp may be the same)
500 */
501struct tbl *
502setint_v(vq, vp)
503	register struct tbl *vq, *vp;
504{
505	int base;
506	long num;
507
508	if ((base = getint(vp, &num)) == -1)
509		return NULL;
510	if (!(vq->flag & INTEGER) && (vq->flag & ALLOC)) {
511		vq->flag &= ~ALLOC;
512		afree(vq->val.s, vq->areap);
513	}
514	vq->val.i = num;
515	if (vq->type == 0) /* default base */
516		vq->type = base;
517	vq->flag |= ISSET|INTEGER;
518	if (vq->flag&SPECIAL)
519		setspec(vq);
520	return vq;
521}
522
523static char *
524formatstr(vp, s)
525	struct tbl *vp;
526	const char *s;
527{
528	int olen, nlen;
529	char *p, *q;
530
531	olen = strlen(s);
532
533	if (vp->flag & (RJUST|LJUST)) {
534		if (!vp->u2.field)	/* default field width */
535			vp->u2.field = olen;
536		nlen = vp->u2.field;
537	} else
538		nlen = olen;
539
540	p = (char *) alloc(nlen + 1, ATEMP);
541	if (vp->flag & (RJUST|LJUST)) {
542		int slen;
543
544		if (vp->flag & RJUST) {
545			const char *r = s + olen;
546			/* strip trailing spaces (at&t ksh uses q[-1] == ' ') */
547			while (r > s && isspace((unsigned char)r[-1]))
548				--r;
549			slen = r - s;
550			if (slen > vp->u2.field) {
551				s += slen - vp->u2.field;
552				slen = vp->u2.field;
553			}
554			shf_snprintf(p, nlen + 1,
555				((vp->flag & ZEROFIL) && digit(*s)) ?
556					  "%0*s%.*s" : "%*s%.*s",
557				vp->u2.field - slen, null, slen, s);
558		} else {
559			/* strip leading spaces/zeros */
560			while (isspace((unsigned char)*s))
561				s++;
562			if (vp->flag & ZEROFIL)
563				while (*s == '0')
564					s++;
565			shf_snprintf(p, nlen + 1, "%-*.*s",
566				vp->u2.field, vp->u2.field, s);
567		}
568	} else
569		memcpy(p, s, olen + 1);
570
571	if (vp->flag & UCASEV_AL) {
572		for (q = p; *q; q++)
573			if (islower((unsigned char)*q))
574				*q = toupper((unsigned char)*q);
575	} else if (vp->flag & LCASEV) {
576		for (q = p; *q; q++)
577			if (isupper((unsigned char)*q))
578				*q = tolower((unsigned char)*q);
579	}
580
581	return p;
582}
583
584/*
585 * make vp->val.s be "name=value" for quick exporting.
586 */
587static void
588export(vp, val)
589	register struct tbl *vp;
590	const char *val;
591{
592	register char *xp;
593	char *op = (vp->flag&ALLOC) ? vp->val.s : NULL;
594	int namelen = strlen(vp->name);
595	int vallen = strlen(val) + 1;
596
597	vp->flag |= ALLOC;
598	xp = (char*)alloc(namelen + 1 + vallen, vp->areap);
599	memcpy(vp->val.s = xp, vp->name, namelen);
600	xp += namelen;
601	*xp++ = '=';
602	vp->type = xp - vp->val.s; /* offset to value */
603	memcpy(xp, val, vallen);
604	if (op != NULL)
605		afree((void*)op, vp->areap);
606}
607
608/*
609 * lookup variable (according to (set&LOCAL)),
610 * set its attributes (INTEGER, RDONLY, EXPORT, TRACE, LJUST, RJUST, ZEROFIL,
611 * LCASEV, UCASEV_AL), and optionally set its value if an assignment.
612 */
613struct tbl *
614typeset(var, set, clr, field, base)
615	register const char *var;
616	Tflag clr, set;
617	int field, base;
618{
619	register struct tbl *vp;
620	struct tbl *vpbase, *t;
621	char *tvar;
622	const char *val;
623
624	/* check for valid variable name, search for value */
625	val = skip_varname(var, FALSE);
626	if (val == var)
627		return NULL;
628	if (*val == '[') {
629		int len;
630
631		len = array_ref_len(val);
632		if (len == 0)
633			return NULL;
634		/* IMPORT is only used when the shell starts up and is
635		 * setting up its environment.  Allow only simple array
636		 * references at this time since parameter/command substitution
637		 * is performed on the [expression], which would be a major
638		 * security hole.
639		 */
640		if (set & IMPORT) {
641			int i;
642			for (i = 1; i < len - 1; i++)
643				if (!digit(val[i]))
644					return NULL;
645		}
646		val += len;
647	}
648	if (*val == '=')
649		tvar = str_nsave(var, val++ - var, ATEMP);
650	else {
651		/* Importing from original environment: must have an = */
652		if (set & IMPORT)
653			return NULL;
654		tvar = (char *) __UNCONST(var);
655		val = NULL;
656	}
657
658	/* Prevent typeset from creating a local PATH/ENV/SHELL */
659	if (Flag(FRESTRICTED) && (strcmp(tvar, "PATH") == 0
660				  || strcmp(tvar, "ENV") == 0
661				  || strcmp(tvar, "SHELL") == 0))
662		errorf("%s: restricted", tvar);
663
664	vp = (set&LOCAL) ? local(tvar, (set & LOCAL_COPY) ? TRUE : FALSE)
665		: global(tvar);
666	set &= ~(LOCAL|LOCAL_COPY);
667
668	vpbase = (vp->flag & ARRAY) ? global(arrayname(var)) : vp;
669
670	/* only allow export flag to be set.  at&t ksh allows any attribute to
671	 * be changed, which means it can be truncated or modified
672	 * (-L/-R/-Z/-i).
673	 */
674	if ((vpbase->flag&RDONLY)
675	    && (val || clr || (set & ~EXPORT)))
676		/* XXX check calls - is error here ok by POSIX? */
677		errorf("%s: is read only", tvar);
678	if (val)
679		afree(tvar, ATEMP);
680
681	/* most calls are with set/clr == 0 */
682	if (set | clr) {
683		int ok = 1;
684		/* XXX if x[0] isn't set, there will be problems: need to have
685		 * one copy of attributes for arrays...
686		 */
687		for (t = vpbase; t; t = t->u.array) {
688			int fake_assign;
689			char UNINITIALIZED(*s);
690			char UNINITIALIZED(*free_me);
691
692			fake_assign = (t->flag & ISSET) && (!val || t != vp)
693				      && ((set & (UCASEV_AL|LCASEV|LJUST|RJUST|ZEROFIL))
694					  || ((t->flag & INTEGER) && (clr & INTEGER))
695					  || (!(t->flag & INTEGER) && (set & INTEGER)));
696			if (fake_assign) {
697				if (t->flag & INTEGER) {
698					s = str_val(t);
699					free_me = (char *) 0;
700				} else {
701					s = t->val.s + t->type;
702					free_me = (t->flag & ALLOC) ? t->val.s
703								  : (char *) 0;
704				}
705				t->flag &= ~ALLOC;
706			}
707			if (!(t->flag & INTEGER) && (set & INTEGER)) {
708				t->type = 0;
709				t->flag &= ~ALLOC;
710			}
711			t->flag = (t->flag | set) & ~clr;
712			/* Don't change base if assignment is to be done,
713			 * in case assignment fails.
714			 */
715			if ((set & INTEGER) && base > 0 && (!val || t != vp))
716				t->type = base;
717			if (set & (LJUST|RJUST|ZEROFIL))
718				t->u2.field = field;
719			if (fake_assign) {
720				if (!setstr(t, s, KSH_RETURN_ERROR)) {
721					/* Somewhat arbitrary action here:
722					 * zap contents of variable, but keep
723					 * the flag settings.
724					 */
725					ok = 0;
726					if (t->flag & INTEGER)
727						t->flag &= ~ISSET;
728					else {
729						if (t->flag & ALLOC)
730							afree((void*) t->val.s,
731							      t->areap);
732						t->flag &= ~(ISSET|ALLOC);
733						t->type = 0;
734					}
735				}
736				if (free_me)
737					afree((void *) free_me, t->areap);
738			}
739		}
740		if (!ok)
741		    errorf("%s", null);
742	}
743
744	if (val != NULL) {
745		if (vp->flag&INTEGER) {
746			/* do not zero base before assignment */
747			setstr(vp, val, KSH_UNWIND_ERROR | 0x4);
748			/* Done after assignment to override default */
749			if (base > 0)
750				vp->type = base;
751		} else
752			/* setstr can't fail (readonly check already done) */
753			setstr(vp, val, KSH_RETURN_ERROR | 0x4);
754	}
755
756	/* only x[0] is ever exported, so use vpbase */
757	if ((vpbase->flag&EXPORT) && !(vpbase->flag&INTEGER)
758	    && vpbase->type == 0)
759		export(vpbase, (vpbase->flag&ISSET) ? vpbase->val.s : null);
760
761	return vp;
762}
763
764/* Unset a variable.  array_ref is set if there was an array reference in
765 * the name lookup (eg, x[2]).
766 */
767void
768unset(vp, array_ref)
769	register struct tbl *vp;
770	int array_ref;
771{
772	if (vp->flag & ALLOC)
773		afree((void*)vp->val.s, vp->areap);
774	if ((vp->flag & ARRAY) && !array_ref) {
775		struct tbl *a, *tmp;
776
777		/* Free up entire array */
778		for (a = vp->u.array; a; ) {
779			tmp = a;
780			a = a->u.array;
781			if (tmp->flag & ALLOC)
782				afree((void *) tmp->val.s, tmp->areap);
783			afree(tmp, tmp->areap);
784		}
785		vp->u.array = (struct tbl *) 0;
786	}
787	/* If foo[0] is being unset, the remainder of the array is kept... */
788	vp->flag &= SPECIAL | (array_ref ? ARRAY|DEFINED : 0);
789	if (vp->flag & SPECIAL)
790		unsetspec(vp);	/* responsible for `unspecial'ing var */
791}
792
793/* return a pointer to the first char past a legal variable name (returns the
794 * argument if there is no legal name, returns * a pointer to the terminating
795 * null if whole string is legal).
796 */
797char *
798skip_varname(s, aok)
799	const char *s;
800	int aok;
801{
802	int alen;
803
804	if (s && letter(*s)) {
805		while (*++s && letnum(*s))
806			;
807		if (aok && *s == '[' && (alen = array_ref_len(s)))
808			s += alen;
809	}
810	return (char *) __UNCONST(s);
811}
812
813/* Return a pointer to the first character past any legal variable name.  */
814char *
815skip_wdvarname(s, aok)
816	const char *s;
817	int aok;	/* skip array de-reference? */
818{
819	if (s[0] == CHAR && letter(s[1])) {
820		do
821			s += 2;
822		while (s[0] == CHAR && letnum(s[1]));
823		if (aok && s[0] == CHAR && s[1] == '[') {
824			/* skip possible array de-reference */
825			const char *p = s;
826			char c;
827			int depth = 0;
828
829			while (1) {
830				if (p[0] != CHAR)
831					break;
832				c = p[1];
833				p += 2;
834				if (c == '[')
835					depth++;
836				else if (c == ']' && --depth == 0) {
837					s = p;
838					break;
839				}
840			}
841		}
842	}
843	return (char *) __UNCONST(s);
844}
845
846/* Check if coded string s is a variable name */
847int
848is_wdvarname(s, aok)
849	const char *s;
850	int aok;
851{
852	char *p = skip_wdvarname(s, aok);
853
854	return p != s && p[0] == EOS;
855}
856
857/* Check if coded string s is a variable assignment */
858int
859is_wdvarassign(s)
860	const char *s;
861{
862	char *p = skip_wdvarname(s, TRUE);
863
864	return p != s && p[0] == CHAR && p[1] == '=';
865}
866
867/*
868 * Make the exported environment from the exported names in the dictionary.
869 */
870char **
871makenv()
872{
873	struct block *l = e->loc;
874	XPtrV env;
875	register struct tbl *vp, **vpp;
876	register int i;
877
878	XPinit(env, 64);
879	for (l = e->loc; l != NULL; l = l->next)
880		for (vpp = l->vars.tbls, i = l->vars.size; --i >= 0; )
881			if ((vp = *vpp++) != NULL
882			    && (vp->flag&(ISSET|EXPORT)) == (ISSET|EXPORT)) {
883				register struct block *l2;
884				register struct tbl *vp2;
885				unsigned h = hash(vp->name);
886
887				/* unexport any redefined instances */
888				for (l2 = l->next; l2 != NULL; l2 = l2->next) {
889					vp2 = tsearch(&l2->vars, vp->name, h);
890					if (vp2 != NULL)
891						vp2->flag &= ~EXPORT;
892				}
893				if ((vp->flag&INTEGER)) {
894					/* integer to string */
895					char *val;
896					val = str_val(vp);
897					vp->flag &= ~(INTEGER|RDONLY);
898					/* setstr can't fail here */
899					setstr(vp, val, KSH_RETURN_ERROR);
900				}
901				XPput(env, vp->val.s);
902			}
903	XPput(env, NULL);
904	return (char **) XPclose(env);
905}
906
907/*
908 * Called after a fork in parent to bump the random number generator.
909 * Done to ensure children will not get the same random number sequence
910 * if the parent doesn't use $RANDOM.
911 */
912void
913change_random()
914{
915    rand();
916}
917
918/*
919 * handle special variables with side effects - PATH, SECONDS.
920 */
921
922/* Test if name is a special parameter */
923static int
924special(name)
925	register const char * name;
926{
927	register struct tbl *tp;
928
929	tp = tsearch(&specials, name, hash(name));
930	return tp && (tp->flag & ISSET) ? tp->type : V_NONE;
931}
932
933/* Make a variable non-special */
934static void
935unspecial(name)
936	register const char * name;
937{
938	register struct tbl *tp;
939
940	tp = tsearch(&specials, name, hash(name));
941	if (tp)
942		tdelete(tp);
943}
944
945#ifdef KSH
946static	time_t	seconds;		/* time SECONDS last set */
947#endif /* KSH */
948static	int	user_lineno;		/* what user set $LINENO to */
949
950static void
951getspec(vp)
952	register struct tbl *vp;
953{
954	switch (special(vp->name)) {
955#ifdef KSH
956	  case V_SECONDS:
957		vp->flag &= ~SPECIAL;
958		/* On start up the value of SECONDS is used before seconds
959		 * has been set - don't do anything in this case
960		 * (see initcoms[] in main.c).
961		 */
962		if (vp->flag & ISSET)
963			setint(vp, (long) (time((time_t *)0) - seconds));
964		vp->flag |= SPECIAL;
965		break;
966	  case V_RANDOM:
967		vp->flag &= ~SPECIAL;
968		setint(vp, (long) (rand() & 0x7fff));
969		vp->flag |= SPECIAL;
970		break;
971#endif /* KSH */
972#ifdef HISTORY
973	  case V_HISTSIZE:
974		vp->flag &= ~SPECIAL;
975		setint(vp, (long) histsize);
976		vp->flag |= SPECIAL;
977		break;
978#endif /* HISTORY */
979	  case V_OPTIND:
980		vp->flag &= ~SPECIAL;
981		setint(vp, (long) user_opt.uoptind);
982		vp->flag |= SPECIAL;
983		break;
984	  case V_LINENO:
985		vp->flag &= ~SPECIAL;
986		setint(vp, (long) current_lineno + user_lineno);
987		vp->flag |= SPECIAL;
988		break;
989	}
990}
991
992static void
993setspec(vp)
994	register struct tbl *vp;
995{
996	char *s;
997
998	switch (special(vp->name)) {
999	  case V_PATH:
1000		if (path)
1001			afree(path, APERM);
1002		path = str_save(str_val(vp), APERM);
1003		flushcom(1);	/* clear tracked aliases */
1004		break;
1005	  case V_IFS:
1006		setctypes(s = str_val(vp), C_IFS);
1007		ifs0 = *s;
1008		break;
1009	  case V_OPTIND:
1010		vp->flag &= ~SPECIAL;
1011		getopts_reset((int) intval(vp));
1012		vp->flag |= SPECIAL;
1013		break;
1014	  case V_POSIXLY_CORRECT:
1015		change_flag(FPOSIX, OF_SPECIAL, 1);
1016		break;
1017	  case V_TMPDIR:
1018		if (tmpdir) {
1019			afree(tmpdir, APERM);
1020			tmpdir = (char *) 0;
1021		}
1022		/* Use tmpdir iff it is an absolute path, is writable and
1023		 * searchable and is a directory...
1024		 */
1025		{
1026			struct stat statb;
1027			s = str_val(vp);
1028			if (ISABSPATH(s) && eaccess(s, W_OK|X_OK) == 0
1029			    && stat(s, &statb) == 0 && S_ISDIR(statb.st_mode))
1030				tmpdir = str_save(s, APERM);
1031		}
1032		break;
1033#ifdef HISTORY
1034	  case V_HISTSIZE:
1035		vp->flag &= ~SPECIAL;
1036		sethistsize((int) intval(vp));
1037		vp->flag |= SPECIAL;
1038		break;
1039	  case V_HISTFILE:
1040		sethistfile(str_val(vp));
1041		break;
1042#endif /* HISTORY */
1043#ifdef EDIT
1044	  case V_VISUAL:
1045		set_editmode(str_val(vp));
1046		break;
1047	  case V_EDITOR:
1048		if (!(global("VISUAL")->flag & ISSET))
1049			set_editmode(str_val(vp));
1050		break;
1051	  case V_COLUMNS:
1052		if ((x_cols = intval(vp)) <= MIN_COLS)
1053			x_cols = MIN_COLS;
1054		break;
1055#endif /* EDIT */
1056#ifdef KSH
1057	  case V_MAIL:
1058		mbset(str_val(vp));
1059		break;
1060	  case V_MAILPATH:
1061		mpset(str_val(vp));
1062		break;
1063	  case V_MAILCHECK:
1064		vp->flag &= ~SPECIAL;
1065		mcset(intval(vp));
1066		vp->flag |= SPECIAL;
1067		break;
1068	  case V_RANDOM:
1069		vp->flag &= ~SPECIAL;
1070		srand((unsigned int)intval(vp));
1071		vp->flag |= SPECIAL;
1072		break;
1073	  case V_SECONDS:
1074		vp->flag &= ~SPECIAL;
1075		seconds = time((time_t*) 0) - intval(vp);
1076		vp->flag |= SPECIAL;
1077		break;
1078	  case V_TMOUT:
1079		/* at&t ksh seems to do this (only listen if integer) */
1080		if (vp->flag & INTEGER)
1081			ksh_tmout = vp->val.i >= 0 ? vp->val.i : 0;
1082		break;
1083#endif /* KSH */
1084	  case V_LINENO:
1085		vp->flag &= ~SPECIAL;
1086		/* The -1 is because line numbering starts at 1. */
1087		user_lineno = (unsigned int) intval(vp) - current_lineno - 1;
1088		vp->flag |= SPECIAL;
1089		break;
1090	}
1091}
1092
1093static void
1094unsetspec(vp)
1095	register struct tbl *vp;
1096{
1097	switch (special(vp->name)) {
1098	  case V_PATH:
1099		if (path)
1100			afree(path, APERM);
1101		path = str_save(def_path, APERM);
1102		flushcom(1);	/* clear tracked aliases */
1103		break;
1104	  case V_IFS:
1105		setctypes(" \t\n", C_IFS);
1106		ifs0 = ' ';
1107		break;
1108	  case V_TMPDIR:
1109		/* should not become unspecial */
1110		if (tmpdir) {
1111			afree(tmpdir, APERM);
1112			tmpdir = (char *) 0;
1113		}
1114		break;
1115#ifdef KSH
1116	  case V_MAIL:
1117		mbset((char *) 0);
1118		break;
1119	  case V_MAILPATH:
1120		mpset((char *) 0);
1121		break;
1122#endif /* KSH */
1123
1124	  case V_LINENO:
1125#ifdef KSH
1126	  case V_MAILCHECK:	/* at&t ksh leaves previous value in place */
1127	  case V_RANDOM:
1128	  case V_SECONDS:
1129	  case V_TMOUT:		/* at&t ksh leaves previous value in place */
1130#endif /* KSH */
1131		unspecial(vp->name);
1132		break;
1133
1134	  /* at&t ksh man page says OPTIND, OPTARG and _ lose special meaning,
1135	   * but OPTARG does not (still set by getopts) and _ is also still
1136	   * set in various places.
1137	   * Don't know what at&t does for:
1138	   *		MAIL, MAILPATH, HISTSIZE, HISTFILE,
1139	   * Unsetting these in at&t ksh does not loose the `specialness':
1140	   *    no effect: IFS, COLUMNS, PATH, TMPDIR,
1141	   *		VISUAL, EDITOR,
1142	   * pdkshisms: no effect:
1143	   *		POSIXLY_CORRECT (use set +o posix instead)
1144	   */
1145	}
1146}
1147
1148/*
1149 * Search for (and possibly create) a table entry starting with
1150 * vp, indexed by val.
1151 */
1152static struct tbl *
1153arraysearch(vp, val)
1154	struct tbl *vp;
1155	int val;
1156{
1157	struct tbl *prev, *curr, *new;
1158	size_t namelen = strlen(vp->name) + 1;
1159
1160	vp->flag |= ARRAY|DEFINED;
1161
1162	/* The table entry is always [0] */
1163	if (val == 0) {
1164		vp->index = 0;
1165		return vp;
1166	}
1167	prev = vp;
1168	curr = vp->u.array;
1169	while (curr && curr->index < val) {
1170		prev = curr;
1171		curr = curr->u.array;
1172	}
1173	if (curr && curr->index == val) {
1174		if (curr->flag&ISSET)
1175			return curr;
1176		else
1177			new = curr;
1178	} else
1179		new = (struct tbl *)alloc(sizeof(struct tbl) + namelen,
1180		    vp->areap);
1181	strlcpy(new->name, vp->name, namelen);
1182	new->flag = vp->flag & ~(ALLOC|DEFINED|ISSET|SPECIAL);
1183	new->type = vp->type;
1184	new->areap = vp->areap;
1185	new->u2.field = vp->u2.field;
1186	new->index = val;
1187	if (curr != new) {		/* not reusing old array entry */
1188		prev->u.array = new;
1189		new->u.array = curr;
1190	}
1191	return new;
1192}
1193
1194/* Return the length of an array reference (eg, [1+2]) - cp is assumed
1195 * to point to the open bracket.  Returns 0 if there is no matching closing
1196 * bracket.
1197 */
1198int
1199array_ref_len(cp)
1200	const char *cp;
1201{
1202	const char *s = cp;
1203	int c;
1204	int depth = 0;
1205
1206	while ((c = *s++) && (c != ']' || --depth))
1207		if (c == '[')
1208			depth++;
1209	if (!c)
1210		return 0;
1211	return s - cp;
1212}
1213
1214/*
1215 * Make a copy of the base of an array name
1216 */
1217char *
1218arrayname(str)
1219	const char *str;
1220{
1221	const char *p;
1222
1223	if ((p = strchr(str, '[')) == 0)
1224		/* Shouldn't happen, but why worry? */
1225		return (char *) __UNCONST(str);
1226
1227	return str_nsave(str, p - str, ATEMP);
1228}
1229
1230/* Set (or overwrite, if !reset) the array variable var to the values in vals.
1231 */
1232void
1233set_array(var, reset, vals)
1234	const char *var;
1235	int reset;
1236	char **vals;
1237{
1238	struct tbl *vp, *vq;
1239	int i;
1240
1241	/* to get local array, use "typeset foo; set -A foo" */
1242	vp = global(var);
1243
1244	/* Note: at&t ksh allows set -A but not set +A of a read-only var */
1245	if ((vp->flag&RDONLY))
1246		errorf("%s: is read only", var);
1247	/* This code is quite non-optimal */
1248	if (reset > 0)
1249		/* trash existing values and attributes */
1250		unset(vp, 0);
1251	/* todo: would be nice for assignment to completely succeed or
1252	 * completely fail.  Only really effects integer arrays:
1253	 * evaluation of some of vals[] may fail...
1254	 */
1255	for (i = 0; vals[i]; i++) {
1256		vq = arraysearch(vp, i);
1257		/* would be nice to deal with errors here... (see above) */
1258		setstr(vq, vals[i], KSH_RETURN_ERROR);
1259	}
1260}
1261