xref: /openbsd-src/bin/ksh/var.c (revision f2da64fbbbf1b03f09f390ab01267c93dfd77c4c) 
1 /*	$OpenBSD: var.c,v 1.57 2016/09/08 15:50:50 millert Exp $	*/
2 
3 #include <sys/stat.h>
4 
5 #include <ctype.h>
6 #include <errno.h>
7 #include <limits.h>
8 #include <stdlib.h>
9 #include <string.h>
10 #include <time.h>
11 #include <unistd.h>
12 
13 #include "sh.h"
14 
15 /*
16  * Variables
17  *
18  * WARNING: unreadable code, needs a rewrite
19  *
20  * if (flag&INTEGER), val.i contains integer value, and type contains base.
21  * otherwise, (val.s + type) contains string value.
22  * if (flag&EXPORT), val.s contains "name=value" for E-Z exporting.
23  */
24 static	struct tbl vtemp;
25 static	struct table specials;
26 static char	*formatstr(struct tbl *, const char *);
27 static void	export(struct tbl *, const char *);
28 static int	special(const char *);
29 static void	unspecial(const char *);
30 static void	getspec(struct tbl *);
31 static void	setspec(struct tbl *);
32 static void	unsetspec(struct tbl *);
33 static struct tbl *arraysearch(struct tbl *, int);
34 
35 /*
36  * create a new block for function calls and simple commands
37  * assume caller has allocated and set up genv->loc
38  */
39 void
40 newblock(void)
41 {
42 	struct block *l;
43 	static char *const empty[] = {null};
44 
45 	l = alloc(sizeof(struct block), ATEMP);
46 	l->flags = 0;
47 	ainit(&l->area); /* todo: could use genv->area (l->area => l->areap) */
48 	if (!genv->loc) {
49 		l->argc = 0;
50 		l->argv = (char **) empty;
51 	} else {
52 		l->argc = genv->loc->argc;
53 		l->argv = genv->loc->argv;
54 	}
55 	l->exit = l->error = NULL;
56 	ktinit(&l->vars, &l->area, 0);
57 	ktinit(&l->funs, &l->area, 0);
58 	l->next = genv->loc;
59 	genv->loc = l;
60 }
61 
62 /*
63  * pop a block handling special variables
64  */
65 void
66 popblock(void)
67 {
68 	struct block *l = genv->loc;
69 	struct tbl *vp, **vpp = l->vars.tbls, *vq;
70 	int i;
71 
72 	genv->loc = l->next;	/* pop block */
73 	for (i = l->vars.size; --i >= 0; )
74 		if ((vp = *vpp++) != NULL && (vp->flag&SPECIAL)) {
75 			if ((vq = global(vp->name))->flag & ISSET)
76 				setspec(vq);
77 			else
78 				unsetspec(vq);
79 		}
80 	if (l->flags & BF_DOGETOPTS)
81 		user_opt = l->getopts_state;
82 	afreeall(&l->area);
83 	afree(l, ATEMP);
84 }
85 
86 /* called by main() to initialize variable data structures */
87 void
88 initvar(void)
89 {
90 	static const struct {
91 		const char *name;
92 		int v;
93 	} names[] = {
94 		{ "COLUMNS",		V_COLUMNS },
95 		{ "IFS",		V_IFS },
96 		{ "OPTIND",		V_OPTIND },
97 		{ "PATH",		V_PATH },
98 		{ "POSIXLY_CORRECT",	V_POSIXLY_CORRECT },
99 		{ "TMPDIR",		V_TMPDIR },
100 #ifdef HISTORY
101 		{ "HISTFILE",		V_HISTFILE },
102 		{ "HISTSIZE",		V_HISTSIZE },
103 #endif /* HISTORY */
104 #ifdef EDIT
105 		{ "EDITOR",		V_EDITOR },
106 		{ "VISUAL",		V_VISUAL },
107 #endif /* EDIT */
108 		{ "MAIL",		V_MAIL },
109 		{ "MAILCHECK",		V_MAILCHECK },
110 		{ "MAILPATH",		V_MAILPATH },
111 		{ "RANDOM",		V_RANDOM },
112 		{ "SECONDS",		V_SECONDS },
113 		{ "TMOUT",		V_TMOUT },
114 		{ "LINENO",		V_LINENO },
115 		{ NULL,	0 }
116 	};
117 	int i;
118 	struct tbl *tp;
119 
120 	ktinit(&specials, APERM, 32); /* must be 2^n (currently 17 specials) */
121 	for (i = 0; names[i].name; i++) {
122 		tp = ktenter(&specials, names[i].name, hash(names[i].name));
123 		tp->flag = DEFINED|ISSET;
124 		tp->type = names[i].v;
125 	}
126 }
127 
128 /* Used to calculate an array index for global()/local().  Sets *arrayp to
129  * non-zero if this is an array, sets *valp to the array index, returns
130  * the basename of the array.
131  */
132 static const char *
133 array_index_calc(const char *n, bool *arrayp, int *valp)
134 {
135 	const char *p;
136 	int len;
137 
138 	*arrayp = false;
139 	p = skip_varname(n, false);
140 	if (p != n && *p == '[' && (len = array_ref_len(p))) {
141 		char *sub, *tmp;
142 		long rval;
143 
144 		/* Calculate the value of the subscript */
145 		*arrayp = true;
146 		tmp = str_nsave(p+1, len-2, ATEMP);
147 		sub = substitute(tmp, 0);
148 		afree(tmp, ATEMP);
149 		n = str_nsave(n, p - n, ATEMP);
150 		evaluate(sub, &rval, KSH_UNWIND_ERROR, true);
151 		if (rval < 0 || rval > INT_MAX)
152 			errorf("%s: subscript %ld out of range", n, rval);
153 		*valp = rval;
154 		afree(sub, ATEMP);
155 	}
156 	return n;
157 }
158 
159 /*
160  * Search for variable, if not found create globally.
161  */
162 struct tbl *
163 global(const char *n)
164 {
165 	struct block *l = genv->loc;
166 	struct tbl *vp;
167 	long	 num;
168 	int c;
169 	unsigned int h;
170 	bool	 array;
171 	int	 val;
172 
173 	/* Check to see if this is an array */
174 	n = array_index_calc(n, &array, &val);
175 	h = hash(n);
176 	c = (unsigned char)n[0];
177 	if (!letter(c)) {
178 		if (array)
179 			errorf("bad substitution");
180 		vp = &vtemp;
181 		vp->flag = DEFINED;
182 		vp->type = 0;
183 		vp->areap = ATEMP;
184 		*vp->name = c;
185 		if (digit(c)) {
186 			errno = 0;
187 			num = strtol(n, NULL, 10);
188 			if (errno == 0 && num <= l->argc)
189 				/* setstr can't fail here */
190 				setstr(vp, l->argv[num], KSH_RETURN_ERROR);
191 			vp->flag |= RDONLY;
192 			return vp;
193 		}
194 		vp->flag |= RDONLY;
195 		if (n[1] != '\0')
196 			return vp;
197 		vp->flag |= ISSET|INTEGER;
198 		switch (c) {
199 		case '$':
200 			vp->val.i = kshpid;
201 			break;
202 		case '!':
203 			/* If no job, expand to nothing */
204 			if ((vp->val.i = j_async()) == 0)
205 				vp->flag &= ~(ISSET|INTEGER);
206 			break;
207 		case '?':
208 			vp->val.i = exstat;
209 			break;
210 		case '#':
211 			vp->val.i = l->argc;
212 			break;
213 		case '-':
214 			vp->flag &= ~INTEGER;
215 			vp->val.s = getoptions();
216 			break;
217 		default:
218 			vp->flag &= ~(ISSET|INTEGER);
219 		}
220 		return vp;
221 	}
222 	for (l = genv->loc; ; l = l->next) {
223 		vp = ktsearch(&l->vars, n, h);
224 		if (vp != NULL) {
225 			if (array)
226 				return arraysearch(vp, val);
227 			else
228 				return vp;
229 		}
230 		if (l->next == NULL)
231 			break;
232 	}
233 	vp = ktenter(&l->vars, n, h);
234 	if (array)
235 		vp = arraysearch(vp, val);
236 	vp->flag |= DEFINED;
237 	if (special(n))
238 		vp->flag |= SPECIAL;
239 	return vp;
240 }
241 
242 /*
243  * Search for local variable, if not found create locally.
244  */
245 struct tbl *
246 local(const char *n, bool copy)
247 {
248 	struct block *l = genv->loc;
249 	struct tbl *vp;
250 	unsigned int h;
251 	bool	 array;
252 	int	 val;
253 
254 	/* Check to see if this is an array */
255 	n = array_index_calc(n, &array, &val);
256 	h = hash(n);
257 	if (!letter(*n)) {
258 		vp = &vtemp;
259 		vp->flag = DEFINED|RDONLY;
260 		vp->type = 0;
261 		vp->areap = ATEMP;
262 		return vp;
263 	}
264 	vp = ktenter(&l->vars, n, h);
265 	if (copy && !(vp->flag & DEFINED)) {
266 		struct block *ll = l;
267 		struct tbl *vq = NULL;
268 
269 		while ((ll = ll->next) && !(vq = ktsearch(&ll->vars, n, h)))
270 			;
271 		if (vq) {
272 			vp->flag |= vq->flag &
273 			    (EXPORT | INTEGER | RDONLY | LJUST | RJUST |
274 			    ZEROFIL | LCASEV | UCASEV_AL | INT_U | INT_L);
275 			if (vq->flag & INTEGER)
276 				vp->type = vq->type;
277 			vp->u2.field = vq->u2.field;
278 		}
279 	}
280 	if (array)
281 		vp = arraysearch(vp, val);
282 	vp->flag |= DEFINED;
283 	if (special(n))
284 		vp->flag |= SPECIAL;
285 	return vp;
286 }
287 
288 /* get variable string value */
289 char *
290 str_val(struct tbl *vp)
291 {
292 	char *s;
293 
294 	if ((vp->flag&SPECIAL))
295 		getspec(vp);
296 	if (!(vp->flag&ISSET))
297 		s = null;		/* special to dollar() */
298 	else if (!(vp->flag&INTEGER))	/* string source */
299 		s = vp->val.s + vp->type;
300 	else {				/* integer source */
301 		/* worst case number length is when base=2, so use BITS(long) */
302 		/* minus base #     number    null */
303 		char strbuf[1 + 2 + 1 + BITS(long) + 1];
304 		const char *digits = (vp->flag & UCASEV_AL) ?
305 		    "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ" :
306 		    "0123456789abcdefghijklmnopqrstuvwxyz";
307 		unsigned long n;
308 		int base;
309 
310 		s = strbuf + sizeof(strbuf);
311 		if (vp->flag & INT_U)
312 			n = (unsigned long) vp->val.i;
313 		else
314 			n = (vp->val.i < 0) ? -vp->val.i : vp->val.i;
315 		base = (vp->type == 0) ? 10 : vp->type;
316 		if (base < 2 || base > strlen(digits))
317 			base = 10;
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 		else
335 			s = str_save(s, ATEMP);
336 	}
337 	return s;
338 }
339 
340 /* get variable integer value, with error checking */
341 long
342 intval(struct tbl *vp)
343 {
344 	long num;
345 	int base;
346 
347 	base = getint(vp, &num, false);
348 	if (base == -1)
349 		/* XXX check calls - is error here ok by POSIX? */
350 		errorf("%s: bad number", str_val(vp));
351 	return num;
352 }
353 
354 /* set variable to string value */
355 int
356 setstr(struct tbl *vq, const char *s, int error_ok)
357 {
358 	const char *fs = NULL;
359 	int no_ro_check = error_ok & KSH_IGNORE_RDONLY;
360 	error_ok &= ~KSH_IGNORE_RDONLY;
361 	if ((vq->flag & RDONLY) && !no_ro_check) {
362 		warningf(true, "%s: is read only", vq->name);
363 		if (!error_ok)
364 			errorf(NULL);
365 		return 0;
366 	}
367 	if (!(vq->flag&INTEGER)) { /* string dest */
368 		if ((vq->flag&ALLOC)) {
369 			/* debugging */
370 			if (s >= vq->val.s &&
371 			    s <= vq->val.s + strlen(vq->val.s))
372 				internal_errorf(true,
373 				    "setstr: %s=%s: assigning to self",
374 				    vq->name, s);
375 			afree(vq->val.s, vq->areap);
376 		}
377 		vq->flag &= ~(ISSET|ALLOC);
378 		vq->type = 0;
379 		if (s && (vq->flag & (UCASEV_AL|LCASEV|LJUST|RJUST)))
380 			fs = s = formatstr(vq, s);
381 		if ((vq->flag&EXPORT))
382 			export(vq, s);
383 		else {
384 			vq->val.s = str_save(s, vq->areap);
385 			vq->flag |= ALLOC;
386 		}
387 	} else {		/* integer dest */
388 		if (!v_evaluate(vq, s, error_ok, true))
389 			return 0;
390 	}
391 	vq->flag |= ISSET;
392 	if ((vq->flag&SPECIAL))
393 		setspec(vq);
394 	afree((void *)fs, ATEMP);
395 	return 1;
396 }
397 
398 /* set variable to integer */
399 void
400 setint(struct tbl *vq, long int n)
401 {
402 	if (!(vq->flag&INTEGER)) {
403 		struct tbl *vp = &vtemp;
404 		vp->flag = (ISSET|INTEGER);
405 		vp->type = 0;
406 		vp->areap = ATEMP;
407 		vp->val.i = n;
408 		/* setstr can't fail here */
409 		setstr(vq, str_val(vp), KSH_RETURN_ERROR);
410 	} else
411 		vq->val.i = n;
412 	vq->flag |= ISSET;
413 	if ((vq->flag&SPECIAL))
414 		setspec(vq);
415 }
416 
417 int
418 getint(struct tbl *vp, long int *nump, bool arith)
419 {
420 	char *s;
421 	int c;
422 	int base, neg;
423 	int have_base = 0;
424 	long num;
425 
426 	if (vp->flag&SPECIAL)
427 		getspec(vp);
428 	/* XXX is it possible for ISSET to be set and val.s to be 0? */
429 	if (!(vp->flag&ISSET) || (!(vp->flag&INTEGER) && vp->val.s == NULL))
430 		return -1;
431 	if (vp->flag&INTEGER) {
432 		*nump = vp->val.i;
433 		return vp->type;
434 	}
435 	s = vp->val.s + vp->type;
436 	if (s == NULL)	/* redundant given initial test */
437 		s = null;
438 	base = 10;
439 	num = 0;
440 	neg = 0;
441 	if (arith && *s == '0' && *(s+1)) {
442 		s++;
443 		if (*s == 'x' || *s == 'X') {
444 			s++;
445 			base = 16;
446 		} else if (vp->flag & ZEROFIL) {
447 			while (*s == '0')
448 				s++;
449 		} else
450 			base = 8;
451 		have_base++;
452 	}
453 	for (c = (unsigned char)*s++; c ; c = (unsigned char)*s++) {
454 		if (c == '-') {
455 			neg++;
456 		} else if (c == '#') {
457 			base = (int) num;
458 			if (have_base || base < 2 || base > 36)
459 				return -1;
460 			num = 0;
461 			have_base = 1;
462 		} else if (letnum(c)) {
463 			if (isdigit(c))
464 				c -= '0';
465 			else if (islower(c))
466 				c -= 'a' - 10; /* todo: assumes ascii */
467 			else if (isupper(c))
468 				c -= 'A' - 10; /* todo: assumes ascii */
469 			else
470 				c = -1; /* _: force error */
471 			if (c < 0 || c >= base)
472 				return -1;
473 			num = num * base + c;
474 		} else
475 			return -1;
476 	}
477 	if (neg)
478 		num = -num;
479 	*nump = num;
480 	return base;
481 }
482 
483 /* convert variable vq to integer variable, setting its value from vp
484  * (vq and vp may be the same)
485  */
486 struct tbl *
487 setint_v(struct tbl *vq, struct tbl *vp, bool arith)
488 {
489 	int base;
490 	long num;
491 
492 	if ((base = getint(vp, &num, arith)) == -1)
493 		return NULL;
494 	if (!(vq->flag & INTEGER) && (vq->flag & ALLOC)) {
495 		vq->flag &= ~ALLOC;
496 		afree(vq->val.s, vq->areap);
497 	}
498 	vq->val.i = num;
499 	if (vq->type == 0) /* default base */
500 		vq->type = base;
501 	vq->flag |= ISSET|INTEGER;
502 	if (vq->flag&SPECIAL)
503 		setspec(vq);
504 	return vq;
505 }
506 
507 static char *
508 formatstr(struct tbl *vp, const char *s)
509 {
510 	int olen, nlen;
511 	char *p, *q;
512 
513 	olen = strlen(s);
514 
515 	if (vp->flag & (RJUST|LJUST)) {
516 		if (!vp->u2.field)	/* default field width */
517 			vp->u2.field = olen;
518 		nlen = vp->u2.field;
519 	} else
520 		nlen = olen;
521 
522 	p = alloc(nlen + 1, ATEMP);
523 	if (vp->flag & (RJUST|LJUST)) {
524 		int slen;
525 
526 		if (vp->flag & RJUST) {
527 			const char *q = s + olen;
528 			/* strip trailing spaces (at&t ksh uses q[-1] == ' ') */
529 			while (q > s && isspace((unsigned char)q[-1]))
530 				--q;
531 			slen = q - s;
532 			if (slen > vp->u2.field) {
533 				s += slen - vp->u2.field;
534 				slen = vp->u2.field;
535 			}
536 			shf_snprintf(p, nlen + 1,
537 				((vp->flag & ZEROFIL) && digit(*s)) ?
538 					  "%0*s%.*s" : "%*s%.*s",
539 				vp->u2.field - slen, null, slen, s);
540 		} else {
541 			/* strip leading spaces/zeros */
542 			while (isspace((unsigned char)*s))
543 				s++;
544 			if (vp->flag & ZEROFIL)
545 				while (*s == '0')
546 					s++;
547 			shf_snprintf(p, nlen + 1, "%-*.*s",
548 				vp->u2.field, vp->u2.field, s);
549 		}
550 	} else
551 		memcpy(p, s, olen + 1);
552 
553 	if (vp->flag & UCASEV_AL) {
554 		for (q = p; *q; q++)
555 			if (islower((unsigned char)*q))
556 				*q = toupper((unsigned char)*q);
557 	} else if (vp->flag & LCASEV) {
558 		for (q = p; *q; q++)
559 			if (isupper((unsigned char)*q))
560 				*q = tolower((unsigned char)*q);
561 	}
562 
563 	return p;
564 }
565 
566 /*
567  * make vp->val.s be "name=value" for quick exporting.
568  */
569 static void
570 export(struct tbl *vp, const char *val)
571 {
572 	char *xp;
573 	char *op = (vp->flag&ALLOC) ? vp->val.s : NULL;
574 	int namelen = strlen(vp->name);
575 	int vallen = strlen(val) + 1;
576 
577 	vp->flag |= ALLOC;
578 	xp = alloc(namelen + 1 + vallen, vp->areap);
579 	memcpy(vp->val.s = xp, vp->name, namelen);
580 	xp += namelen;
581 	*xp++ = '=';
582 	vp->type = xp - vp->val.s; /* offset to value */
583 	memcpy(xp, val, vallen);
584 	afree(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(const char *var, int set, int clr, int field, int base)
594 {
595 	struct tbl *vp;
596 	struct tbl *vpbase, *t;
597 	char *tvar;
598 	const char *val;
599 
600 	/* check for valid variable name, search for value */
601 	val = skip_varname(var, false);
602 	if (val == var)
603 		return NULL;
604 	if (*val == '[') {
605 		int len;
606 
607 		len = array_ref_len(val);
608 		if (len == 0)
609 			return NULL;
610 		/* IMPORT is only used when the shell starts up and is
611 		 * setting up its environment.  Allow only simple array
612 		 * references at this time since parameter/command substitution
613 		 * is preformed on the [expression], which would be a major
614 		 * security hole.
615 		 */
616 		if (set & IMPORT) {
617 			int i;
618 			for (i = 1; i < len - 1; i++)
619 				if (!digit(val[i]))
620 					return NULL;
621 		}
622 		val += len;
623 	}
624 	if (*val == '=')
625 		tvar = str_nsave(var, val++ - var, ATEMP);
626 	else {
627 		/* Importing from original environment: must have an = */
628 		if (set & IMPORT)
629 			return NULL;
630 		tvar = (char *) var;
631 		val = NULL;
632 	}
633 
634 	/* Prevent typeset from creating a local PATH/ENV/SHELL */
635 	if (Flag(FRESTRICTED) && (strcmp(tvar, "PATH") == 0 ||
636 	    strcmp(tvar, "ENV") == 0 || strcmp(tvar, "SHELL") == 0))
637 		errorf("%s: restricted", tvar);
638 
639 	vp = (set&LOCAL) ? local(tvar, (set & LOCAL_COPY) ? true : false) :
640 	    global(tvar);
641 	set &= ~(LOCAL|LOCAL_COPY);
642 
643 	vpbase = (vp->flag & ARRAY) ? global(arrayname(var)) : vp;
644 
645 	/* only allow export flag to be set.  at&t ksh allows any attribute to
646 	 * be changed, which means it can be truncated or modified
647 	 * (-L/-R/-Z/-i).
648 	 */
649 	if ((vpbase->flag&RDONLY) &&
650 	    (val || clr || (set & ~EXPORT)))
651 		/* XXX check calls - is error here ok by POSIX? */
652 		errorf("%s: is read only", tvar);
653 	if (val)
654 		afree(tvar, ATEMP);
655 
656 	/* most calls are with set/clr == 0 */
657 	if (set | clr) {
658 		int ok = 1;
659 		/* XXX if x[0] isn't set, there will be problems: need to have
660 		 * one copy of attributes for arrays...
661 		 */
662 		for (t = vpbase; t; t = t->u.array) {
663 			int fake_assign;
664 			int error_ok = KSH_RETURN_ERROR;
665 			char *s = NULL;
666 			char *free_me = NULL;
667 
668 			fake_assign = (t->flag & ISSET) && (!val || t != vp) &&
669 			    ((set & (UCASEV_AL|LCASEV|LJUST|RJUST|ZEROFIL)) ||
670 			    ((t->flag & INTEGER) && (clr & INTEGER)) ||
671 			    (!(t->flag & INTEGER) && (set & INTEGER)));
672 			if (fake_assign) {
673 				if (t->flag & INTEGER) {
674 					s = str_val(t);
675 					free_me = NULL;
676 				} else {
677 					s = t->val.s + t->type;
678 					free_me = (t->flag & ALLOC) ? t->val.s :
679 					    NULL;
680 				}
681 				t->flag &= ~ALLOC;
682 			}
683 			if (!(t->flag & INTEGER) && (set & INTEGER)) {
684 				t->type = 0;
685 				t->flag &= ~ALLOC;
686 			}
687 			if (!(t->flag & RDONLY) && (set & RDONLY)) {
688 				/* allow var to be initialized read-only */
689 				error_ok |= KSH_IGNORE_RDONLY;
690 			}
691 			t->flag = (t->flag | set) & ~clr;
692 			/* Don't change base if assignment is to be done,
693 			 * in case assignment fails.
694 			 */
695 			if ((set & INTEGER) && base > 0 && (!val || t != vp))
696 				t->type = base;
697 			if (set & (LJUST|RJUST|ZEROFIL))
698 				t->u2.field = field;
699 			if (fake_assign) {
700 				if (!setstr(t, s, error_ok)) {
701 					/* Somewhat arbitrary action here:
702 					 * zap contents of variable, but keep
703 					 * the flag settings.
704 					 */
705 					ok = 0;
706 					if (t->flag & INTEGER)
707 						t->flag &= ~ISSET;
708 					else {
709 						if (t->flag & ALLOC)
710 							afree(t->val.s, t->areap);
711 						t->flag &= ~(ISSET|ALLOC);
712 						t->type = 0;
713 					}
714 				}
715 				afree(free_me, t->areap);
716 			}
717 		}
718 		if (!ok)
719 		    errorf(NULL);
720 	}
721 
722 	if (val != NULL) {
723 		if (vp->flag&INTEGER) {
724 			/* do not zero base before assignment */
725 			setstr(vp, val, KSH_UNWIND_ERROR | KSH_IGNORE_RDONLY);
726 			/* Done after assignment to override default */
727 			if (base > 0)
728 				vp->type = base;
729 		} else
730 			/* setstr can't fail (readonly check already done) */
731 			setstr(vp, val, KSH_RETURN_ERROR | KSH_IGNORE_RDONLY);
732 	}
733 
734 	/* only x[0] is ever exported, so use vpbase */
735 	if ((vpbase->flag&EXPORT) && !(vpbase->flag&INTEGER) &&
736 	    vpbase->type == 0)
737 		export(vpbase, (vpbase->flag&ISSET) ? vpbase->val.s : null);
738 
739 	return vp;
740 }
741 
742 /* Unset a variable.  array_ref is set if there was an array reference in
743  * the name lookup (eg, x[2]).
744  */
745 void
746 unset(struct tbl *vp, int array_ref)
747 {
748 	if (vp->flag & ALLOC)
749 		afree(vp->val.s, vp->areap);
750 	if ((vp->flag & ARRAY) && !array_ref) {
751 		struct tbl *a, *tmp;
752 
753 		/* Free up entire array */
754 		for (a = vp->u.array; a; ) {
755 			tmp = a;
756 			a = a->u.array;
757 			if (tmp->flag & ALLOC)
758 				afree(tmp->val.s, tmp->areap);
759 			afree(tmp, tmp->areap);
760 		}
761 		vp->u.array = NULL;
762 	}
763 	/* If foo[0] is being unset, the remainder of the array is kept... */
764 	vp->flag &= SPECIAL | (array_ref ? ARRAY|DEFINED : 0);
765 	if (vp->flag & SPECIAL)
766 		unsetspec(vp);	/* responsible for `unspecial'ing var */
767 }
768 
769 /* return a pointer to the first char past a legal variable name (returns the
770  * argument if there is no legal name, returns * a pointer to the terminating
771  * null if whole string is legal).
772  */
773 char *
774 skip_varname(const char *s, int aok)
775 {
776 	int alen;
777 
778 	if (s && letter(*s)) {
779 		while (*++s && letnum(*s))
780 			;
781 		if (aok && *s == '[' && (alen = array_ref_len(s)))
782 			s += alen;
783 	}
784 	return (char *) s;
785 }
786 
787 /* Return a pointer to the first character past any legal variable name.  */
788 char *
789 skip_wdvarname(const char *s,
790     int aok)				/* skip array de-reference? */
791 {
792 	if (s[0] == CHAR && letter(s[1])) {
793 		do {
794 			s += 2;
795 		} while (s[0] == CHAR && letnum(s[1]));
796 		if (aok && s[0] == CHAR && s[1] == '[') {
797 			/* skip possible array de-reference */
798 			const char *p = s;
799 			char c;
800 			int depth = 0;
801 
802 			while (1) {
803 				if (p[0] != CHAR)
804 					break;
805 				c = p[1];
806 				p += 2;
807 				if (c == '[')
808 					depth++;
809 				else if (c == ']' && --depth == 0) {
810 					s = p;
811 					break;
812 				}
813 			}
814 		}
815 	}
816 	return (char *) s;
817 }
818 
819 /* Check if coded string s is a variable name */
820 int
821 is_wdvarname(const char *s, int aok)
822 {
823 	char *p = skip_wdvarname(s, aok);
824 
825 	return p != s && p[0] == EOS;
826 }
827 
828 /* Check if coded string s is a variable assignment */
829 int
830 is_wdvarassign(const char *s)
831 {
832 	char *p = skip_wdvarname(s, true);
833 
834 	return p != s && p[0] == CHAR && p[1] == '=';
835 }
836 
837 /*
838  * Make the exported environment from the exported names in the dictionary.
839  */
840 char **
841 makenv(void)
842 {
843 	struct block *l;
844 	XPtrV env;
845 	struct tbl *vp, **vpp;
846 	int i;
847 
848 	XPinit(env, 64);
849 	for (l = genv->loc; l != NULL; l = l->next)
850 		for (vpp = l->vars.tbls, i = l->vars.size; --i >= 0; )
851 			if ((vp = *vpp++) != NULL &&
852 			    (vp->flag&(ISSET|EXPORT)) == (ISSET|EXPORT)) {
853 				struct block *l2;
854 				struct tbl *vp2;
855 				unsigned int h = hash(vp->name);
856 
857 				/* unexport any redefined instances */
858 				for (l2 = l->next; l2 != NULL; l2 = l2->next) {
859 					vp2 = ktsearch(&l2->vars, vp->name, h);
860 					if (vp2 != NULL)
861 						vp2->flag &= ~EXPORT;
862 				}
863 				if ((vp->flag&INTEGER)) {
864 					/* integer to string */
865 					char *val;
866 					val = str_val(vp);
867 					vp->flag &= ~(INTEGER|RDONLY);
868 					/* setstr can't fail here */
869 					setstr(vp, val, KSH_RETURN_ERROR);
870 				}
871 				XPput(env, vp->val.s);
872 			}
873 	XPput(env, NULL);
874 	return (char **) XPclose(env);
875 }
876 
877 /*
878  * Called after a fork in parent to bump the random number generator.
879  * Done to ensure children will not get the same random number sequence
880  * if the parent doesn't use $RANDOM.
881  */
882 void
883 change_random(void)
884 {
885 	rand();
886 }
887 
888 /*
889  * handle special variables with side effects - PATH, SECONDS.
890  */
891 
892 /* Test if name is a special parameter */
893 static int
894 special(const char *name)
895 {
896 	struct tbl *tp;
897 
898 	tp = ktsearch(&specials, name, hash(name));
899 	return tp && (tp->flag & ISSET) ? tp->type : V_NONE;
900 }
901 
902 /* Make a variable non-special */
903 static void
904 unspecial(const char *name)
905 {
906 	struct tbl *tp;
907 
908 	tp = ktsearch(&specials, name, hash(name));
909 	if (tp)
910 		ktdelete(tp);
911 }
912 
913 static	time_t	seconds;		/* time SECONDS last set */
914 static	int	user_lineno;		/* what user set $LINENO to */
915 
916 static void
917 getspec(struct tbl *vp)
918 {
919 	switch (special(vp->name)) {
920 	case V_SECONDS:
921 		vp->flag &= ~SPECIAL;
922 		/* On start up the value of SECONDS is used before seconds
923 		 * has been set - don't do anything in this case
924 		 * (see initcoms[] in main.c).
925 		 */
926 		if (vp->flag & ISSET)
927 			setint(vp, (long)(time(NULL) - seconds)); /* XXX 2038 */
928 		vp->flag |= SPECIAL;
929 		break;
930 	case V_RANDOM:
931 		vp->flag &= ~SPECIAL;
932 		setint(vp, (long) (rand() & 0x7fff));
933 		vp->flag |= SPECIAL;
934 		break;
935 #ifdef HISTORY
936 	case V_HISTSIZE:
937 		vp->flag &= ~SPECIAL;
938 		setint(vp, (long) histsize);
939 		vp->flag |= SPECIAL;
940 		break;
941 #endif /* HISTORY */
942 	case V_OPTIND:
943 		vp->flag &= ~SPECIAL;
944 		setint(vp, (long) user_opt.uoptind);
945 		vp->flag |= SPECIAL;
946 		break;
947 	case V_LINENO:
948 		vp->flag &= ~SPECIAL;
949 		setint(vp, (long) current_lineno + user_lineno);
950 		vp->flag |= SPECIAL;
951 		break;
952 	}
953 }
954 
955 static void
956 setspec(struct tbl *vp)
957 {
958 	char *s;
959 
960 	switch (special(vp->name)) {
961 	case V_PATH:
962 		afree(path, APERM);
963 		path = str_save(str_val(vp), APERM);
964 		flushcom(1);	/* clear tracked aliases */
965 		break;
966 	case V_IFS:
967 		setctypes(s = str_val(vp), C_IFS);
968 		ifs0 = *s;
969 		break;
970 	case V_OPTIND:
971 		vp->flag &= ~SPECIAL;
972 		getopts_reset((int) intval(vp));
973 		vp->flag |= SPECIAL;
974 		break;
975 	case V_POSIXLY_CORRECT:
976 		change_flag(FPOSIX, OF_SPECIAL, 1);
977 		break;
978 	case V_TMPDIR:
979 		if (tmpdir) {
980 			afree(tmpdir, APERM);
981 			tmpdir = NULL;
982 		}
983 		/* Use tmpdir iff it is an absolute path, is writable and
984 		 * searchable and is a directory...
985 		 */
986 		{
987 			struct stat statb;
988 
989 			s = str_val(vp);
990 			if (s[0] == '/' && access(s, W_OK|X_OK) == 0 &&
991 			    stat(s, &statb) == 0 && S_ISDIR(statb.st_mode))
992 				tmpdir = str_save(s, APERM);
993 		}
994 		break;
995 #ifdef HISTORY
996 	case V_HISTSIZE:
997 		vp->flag &= ~SPECIAL;
998 		sethistsize((int) intval(vp));
999 		vp->flag |= SPECIAL;
1000 		break;
1001 	case V_HISTFILE:
1002 		sethistfile(str_val(vp));
1003 		break;
1004 #endif /* HISTORY */
1005 #ifdef EDIT
1006 	case V_VISUAL:
1007 		set_editmode(str_val(vp));
1008 		break;
1009 	case V_EDITOR:
1010 		if (!(global("VISUAL")->flag & ISSET))
1011 			set_editmode(str_val(vp));
1012 		break;
1013 	case V_COLUMNS:
1014 		{
1015 			long l;
1016 
1017 			if (getint(vp, &l, false) == -1) {
1018 				x_cols = MIN_COLS;
1019 				break;
1020 			}
1021 			if (l <= MIN_COLS || l > INT_MAX)
1022 				x_cols = MIN_COLS;
1023 			else
1024 				x_cols = l;
1025 		}
1026 		break;
1027 #endif /* EDIT */
1028 	case V_MAIL:
1029 		mbset(str_val(vp));
1030 		break;
1031 	case V_MAILPATH:
1032 		mpset(str_val(vp));
1033 		break;
1034 	case V_MAILCHECK:
1035 		vp->flag &= ~SPECIAL;
1036 		mcset(intval(vp));
1037 		vp->flag |= SPECIAL;
1038 		break;
1039 	case V_RANDOM:
1040 		vp->flag &= ~SPECIAL;
1041 		srand_deterministic((unsigned int)intval(vp));
1042 		vp->flag |= SPECIAL;
1043 		break;
1044 	case V_SECONDS:
1045 		vp->flag &= ~SPECIAL;
1046 		seconds = time(NULL) - intval(vp); /* XXX 2038 */
1047 		vp->flag |= SPECIAL;
1048 		break;
1049 	case V_TMOUT:
1050 		/* at&t ksh seems to do this (only listen if integer) */
1051 		if (vp->flag & INTEGER)
1052 			ksh_tmout = vp->val.i >= 0 ? vp->val.i : 0;
1053 		break;
1054 	case V_LINENO:
1055 		vp->flag &= ~SPECIAL;
1056 		/* The -1 is because line numbering starts at 1. */
1057 		user_lineno = (unsigned int) intval(vp) - current_lineno - 1;
1058 		vp->flag |= SPECIAL;
1059 		break;
1060 	}
1061 }
1062 
1063 static void
1064 unsetspec(struct tbl *vp)
1065 {
1066 	switch (special(vp->name)) {
1067 	case V_PATH:
1068 		afree(path, APERM);
1069 		path = str_save(def_path, APERM);
1070 		flushcom(1);	/* clear tracked aliases */
1071 		break;
1072 	case V_IFS:
1073 		setctypes(" \t\n", C_IFS);
1074 		ifs0 = ' ';
1075 		break;
1076 	case V_TMPDIR:
1077 		/* should not become unspecial */
1078 		if (tmpdir) {
1079 			afree(tmpdir, APERM);
1080 			tmpdir = NULL;
1081 		}
1082 		break;
1083 	case V_MAIL:
1084 		mbset(NULL);
1085 		break;
1086 	case V_MAILPATH:
1087 		mpset(NULL);
1088 		break;
1089 	case V_LINENO:
1090 	case V_MAILCHECK:	/* at&t ksh leaves previous value in place */
1091 	case V_RANDOM:
1092 	case V_SECONDS:
1093 	case V_TMOUT:		/* at&t ksh leaves previous value in place */
1094 		unspecial(vp->name);
1095 		break;
1096 
1097 	  /* at&t ksh man page says OPTIND, OPTARG and _ lose special meaning,
1098 	   * but OPTARG does not (still set by getopts) and _ is also still
1099 	   * set in various places.
1100 	   * Don't know what at&t does for:
1101 	   *		MAIL, MAILPATH, HISTSIZE, HISTFILE,
1102 	   * Unsetting these in at&t ksh does not loose the `specialness':
1103 	   *    no effect: IFS, COLUMNS, PATH, TMPDIR,
1104 	   *		VISUAL, EDITOR,
1105 	   * pdkshisms: no effect:
1106 	   *		POSIXLY_CORRECT (use set +o posix instead)
1107 	   */
1108 	}
1109 }
1110 
1111 /*
1112  * Search for (and possibly create) a table entry starting with
1113  * vp, indexed by val.
1114  */
1115 static struct tbl *
1116 arraysearch(struct tbl *vp, int val)
1117 {
1118 	struct tbl *prev, *curr, *new;
1119 	size_t namelen = strlen(vp->name) + 1;
1120 
1121 	vp->flag |= ARRAY|DEFINED;
1122 	vp->index = 0;
1123 	/* The table entry is always [0] */
1124 	if (val == 0)
1125 		return vp;
1126 	prev = vp;
1127 	curr = vp->u.array;
1128 	while (curr && curr->index < val) {
1129 		prev = curr;
1130 		curr = curr->u.array;
1131 	}
1132 	if (curr && curr->index == val) {
1133 		if (curr->flag&ISSET)
1134 			return curr;
1135 		else
1136 			new = curr;
1137 	} else
1138 		new = alloc(sizeof(struct tbl) + namelen,
1139 		    vp->areap);
1140 	strlcpy(new->name, vp->name, namelen);
1141 	new->flag = vp->flag & ~(ALLOC|DEFINED|ISSET|SPECIAL);
1142 	new->type = vp->type;
1143 	new->areap = vp->areap;
1144 	new->u2.field = vp->u2.field;
1145 	new->index = val;
1146 	if (curr != new) {		/* not reusing old array entry */
1147 		prev->u.array = new;
1148 		new->u.array = curr;
1149 	}
1150 	return new;
1151 }
1152 
1153 /* Return the length of an array reference (eg, [1+2]) - cp is assumed
1154  * to point to the open bracket.  Returns 0 if there is no matching closing
1155  * bracket.
1156  */
1157 int
1158 array_ref_len(const char *cp)
1159 {
1160 	const char *s = cp;
1161 	int c;
1162 	int depth = 0;
1163 
1164 	while ((c = *s++) && (c != ']' || --depth))
1165 		if (c == '[')
1166 			depth++;
1167 	if (!c)
1168 		return 0;
1169 	return s - cp;
1170 }
1171 
1172 /*
1173  * Make a copy of the base of an array name
1174  */
1175 char *
1176 arrayname(const char *str)
1177 {
1178 	const char *p;
1179 
1180 	if ((p = strchr(str, '[')) == 0)
1181 		/* Shouldn't happen, but why worry? */
1182 		return (char *) str;
1183 
1184 	return str_nsave(str, p - str, ATEMP);
1185 }
1186 
1187 /* Set (or overwrite, if !reset) the array variable var to the values in vals.
1188  */
1189 void
1190 set_array(const char *var, int reset, char **vals)
1191 {
1192 	struct tbl *vp, *vq;
1193 	int i;
1194 
1195 	/* to get local array, use "typeset foo; set -A foo" */
1196 	vp = global(var);
1197 
1198 	/* Note: at&t ksh allows set -A but not set +A of a read-only var */
1199 	if ((vp->flag&RDONLY))
1200 		errorf("%s: is read only", var);
1201 	/* This code is quite non-optimal */
1202 	if (reset > 0)
1203 		/* trash existing values and attributes */
1204 		unset(vp, 0);
1205 	/* todo: would be nice for assignment to completely succeed or
1206 	 * completely fail.  Only really effects integer arrays:
1207 	 * evaluation of some of vals[] may fail...
1208 	 */
1209 	for (i = 0; vals[i]; i++) {
1210 		vq = arraysearch(vp, i);
1211 		/* would be nice to deal with errors here... (see above) */
1212 		setstr(vq, vals[i], KSH_RETURN_ERROR);
1213 	}
1214 }
1215