xref: /netbsd-src/bin/ksh/var.c (revision 84d0ab551791493d2630bbef27063a9d514b9108) 
1 /*	$NetBSD: var.c,v 1.3 1997/07/20 17:42:09 christos Exp $	*/
2 
3 #include "sh.h"
4 #include "ksh_time.h"
5 #include "ksh_limval.h"
6 #include "ksh_stat.h"
7 #include <ctype.h>
8 
9 /*
10  * Variables
11  *
12  * WARNING: unreadable code, needs a rewrite
13  *
14  * if (flag&INTEGER), val.i contains integer value, and type contains base.
15  * otherwise, (val.s + type) contains string value.
16  * if (flag&EXPORT), val.s contains "name=value" for E-Z exporting.
17  */
18 static	struct tbl vtemp;
19 static	struct table specials;
20 static char	*formatstr	ARGS((struct tbl *vp, const char *s));
21 static void	export		ARGS((struct tbl *vp, const char *val));
22 static int	special		ARGS((const char *name));
23 static void	getspec		ARGS((struct tbl *vp));
24 static void	setspec		ARGS((struct tbl *vp));
25 static void	unsetspec	ARGS((struct tbl *vp));
26 static struct tbl *arraysearch  ARGS((struct tbl *, int));
27 static const char *array_index_calc ARGS((const char *, bool_t *, 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 	ainit(&l->area);
41 	if (!e->loc) {
42 		l->argc = 0;
43 		l->argv = (char **) empty;
44 	} else {
45 		l->argc = e->loc->argc;
46 		l->argv = e->loc->argv;
47 	}
48 	l->exit = l->error = NULL;
49 	tinit(&l->vars, &l->area, 0);
50 	tinit(&l->funs, &l->area, 0);
51 	l->next = e->loc;
52 	e->loc = l;
53 }
54 
55 /*
56  * pop a block handling special variables
57  */
58 void
59 popblock()
60 {
61 	register struct block *l = e->loc;
62 	register struct tbl *vp, **vpp = l->vars.tbls, *vq;
63 	register int i;
64 
65 	e->loc = l->next;	/* pop block */
66 	for (i = l->vars.size; --i >= 0; )
67 		if ((vp = *vpp++) != NULL && (vp->flag&SPECIAL))
68 			if ((vq = global(vp->name))->flag & ISSET)
69 				setspec(vq);
70 			else
71 				unsetspec(vq);
72 	afreeall(&l->area);
73 	afree(l, ATEMP);
74 }
75 
76 /* called by main() to initialize variable data structures */
77 void
78 initvar()
79 {
80 	static const struct {
81 		const char *name;
82 		int v;
83 	} names[] = {
84 			{ "COLUMNS",		V_COLUMNS },
85 			{ "IFS",		V_IFS },
86 			{ "OPTIND",		V_OPTIND },
87 			{ "PATH",		V_PATH },
88 			{ "POSIXLY_CORRECT",	V_POSIXLY_CORRECT },
89 			{ "TMPDIR",		V_TMPDIR },
90 #ifdef HISTORY
91 			{ "HISTFILE",		V_HISTFILE },
92 			{ "HISTSIZE",		V_HISTSIZE },
93 #endif /* HISTORY */
94 #ifdef EDIT
95 			{ "EDITOR",		V_EDITOR },
96 			{ "VISUAL",		V_VISUAL },
97 #endif /* EDIT */
98 #ifdef KSH
99 			{ "MAIL",		V_MAIL },
100 			{ "MAILCHECK",		V_MAILCHECK },
101 			{ "MAILPATH",		V_MAILPATH },
102 			{ "RANDOM",		V_RANDOM },
103 			{ "SECONDS",		V_SECONDS },
104 			{ "TMOUT",		V_TMOUT },
105 #endif /* KSH */
106 			{ (char *) 0,	0 }
107 		};
108 	int i;
109 	struct tbl *tp;
110 
111 	tinit(&specials, APERM, 32); /* must be 2^n (currently 16 speciasl) */
112 	for (i = 0; names[i].name; i++) {
113 		tp = tenter(&specials, names[i].name, hash(names[i].name));
114 		tp->flag = DEFINED|ISSET;
115 		tp->type = names[i].v;
116 	}
117 }
118 
119 /* Used to calculate an array index for global()/local().  Sets *arrayp to
120  * non-zero if this is an array, sets *valp to the array index, returns
121  * the basename of the array.
122  */
123 static const char *
124 array_index_calc(n, arrayp, valp)
125 	const char *n;
126 	bool_t *arrayp;
127 	int *valp;
128 {
129 	const char *p;
130 	int len;
131 
132 	*arrayp = FALSE;
133 	p = skip_varname(n, FALSE);
134 	if (p != n && *p == '[' && (len = array_ref_len(p))) {
135 		char *sub, *tmp;
136 		long rval;
137 
138 		/* Calculate the value of the subscript */
139 		*arrayp = TRUE;
140 		tmp = str_nsave(p+1, len-2, ATEMP);
141 		sub = substitute(tmp, 0);
142 		afree(tmp, ATEMP);
143 		n = str_nsave(n, p - n, ATEMP);
144 		evaluate(sub, &rval, FALSE);
145 		if (rval < 0 || rval > ARRAYMAX)
146 			errorf("%s: subscript out of range", n);
147 		*valp = rval;
148 		afree(sub, ATEMP);
149 	}
150 	return n;
151 }
152 
153 /*
154  * Search for variable, if not found create globally.
155  */
156 struct tbl *
157 global(n)
158 	register const char *n;
159 {
160 	register struct block *l = e->loc;
161 	register struct tbl *vp;
162 	register int c;
163 	unsigned h;
164 	bool_t	 array;
165 	int	 val;
166 
167 	/* Check to see if this is an array */
168 	n = array_index_calc(n, &array, &val);
169 	h = hash(n);
170 	c = n[0];
171 	if (!letter(c)) {
172 		if (array)
173 			errorf("bad substitution");
174 		vp = &vtemp;
175 		vp->flag = (DEFINED|RDONLY);
176 		vp->type = 0;
177 		vp->areap = ATEMP;
178 		*vp->name = c;
179 		if (digit(c)) {
180 			for (c = 0; digit(*n); n++)
181 				c = c*10 + *n-'0';
182 			if (c <= l->argc)
183 				setstr(vp, l->argv[c]);
184 			return vp;
185 		}
186 		if (n[1] != '\0')
187 			return vp;
188 		vp->flag |= ISSET|INTEGER;
189 		switch (c) {
190 		  case '$':
191 			vp->val.i = kshpid;
192 			break;
193 		  case '!':
194 			/* If no job, expand to nothing */
195 			if ((vp->val.i = j_async()) == 0)
196 				vp->flag &= ~(ISSET|INTEGER);
197 			break;
198 		  case '?':
199 			vp->val.i = exstat;
200 			break;
201 		  case '#':
202 			vp->val.i = l->argc;
203 			break;
204 		  case '-':
205 			vp->flag &= ~INTEGER;
206 			vp->val.s = getoptions();
207 			break;
208 		  default:
209 			vp->flag &= ~(ISSET|INTEGER);
210 		}
211 		return vp;
212 	}
213 	for (l = e->loc; ; l = l->next) {
214 		vp = tsearch(&l->vars, n, h);
215 		if (vp != NULL)
216 			if (array)
217 				return arraysearch(vp, val);
218 			else
219 				return vp;
220 		if (l->next == NULL)
221 			break;
222 	}
223 	vp = tenter(&l->vars, n, h);
224 	if (array)
225 		vp = arraysearch(vp, val);
226 	vp->flag |= DEFINED;
227 	if (special(n))
228 		vp->flag |= SPECIAL;
229 	return vp;
230 }
231 
232 /*
233  * Search for local variable, if not found create locally.
234  */
235 struct tbl *
236 local(n, copy)
237 	register const char *n;
238 	bool_t copy;
239 {
240 	register struct block *l = e->loc;
241 	register struct tbl *vp;
242 	unsigned h;
243 	bool_t	 array;
244 	int	 val;
245 
246 	/* Check to see if this is an array */
247 	n = array_index_calc(n, &array, &val);
248 	h = hash(n);
249 	if (!letter(*n)) {
250 		vp = &vtemp;
251 		vp->flag = DEFINED|RDONLY;
252 		vp->type = 0;
253 		vp->areap = ATEMP;
254 		return vp;
255 	}
256 	vp = tenter(&l->vars, n, h);
257 	if (copy && !(vp->flag & DEFINED)) {
258 		struct block *ll = l;
259 		struct tbl *vq = (struct tbl *) 0;
260 
261 		while ((ll = ll->next) && !(vq = tsearch(&ll->vars, n, h)))
262 			;
263 		if (vq) {
264 			vp->flag |= vq->flag & (EXPORT|INTEGER|RDONLY
265 						|LJUST|RJUST|ZEROFIL
266 						|LCASEV|UCASEV_AL|INT_U|INT_L);
267 			if (vq->flag & INTEGER)
268 				vp->type = vq->type;
269 			vp->u2.field = vq->u2.field;
270 		}
271 	}
272 	if (array)
273 		vp = arraysearch(vp, val);
274 	vp->flag |= DEFINED;
275 	if (special(n))
276 		vp->flag |= SPECIAL;
277 	return vp;
278 }
279 
280 /* get variable string value */
281 char *
282 str_val(vp)
283 	register struct tbl *vp;
284 {
285 	char *s;
286 
287 	if ((vp->flag&SPECIAL))
288 		getspec(vp);
289 	if (!(vp->flag&ISSET))
290 		s = null;		/* special to dollar() */
291 	else if (!(vp->flag&INTEGER))	/* string source */
292 		s = vp->val.s + vp->type;
293 	else {				/* integer source */
294 		/* worst case number length is when base=2, so use BITS(long) */
295 			     /* minus base #     number    null */
296 		static char strbuf[1 + 2 + 1 + BITS(long) + 1];
297 		const char *digits = (vp->flag & UCASEV_AL) ?
298 				  "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
299 				: "0123456789abcdefghijklmnopqrstuvwxyz";
300 		register unsigned long n;
301 		register int base;
302 
303 		s = strbuf + sizeof(strbuf);
304 		if (vp->flag & INT_U)
305 			n = (unsigned long) vp->val.i;
306 		else
307 			n = (vp->val.i < 0) ? -vp->val.i : vp->val.i;
308 		base = (vp->type == 0) ? 10 : vp->type;
309 
310 		*--s = '\0';
311 		do {
312 			*--s = digits[n % base];
313 			n /= base;
314 		} while (n != 0);
315 		if (base != 10) {
316 			*--s = '#';
317 			*--s = digits[base % 10];
318 			if (base >= 10)
319 				*--s = digits[base / 10];
320 		}
321 		if (!(vp->flag & INT_U) && vp->val.i < 0)
322 			*--s = '-';
323 		if (vp->flag & (RJUST|LJUST)) /* case already dealt with */
324 			s = formatstr(vp, s);
325 	}
326 	return s;
327 }
328 
329 /* get variable integer value, with error checking */
330 long
331 intval(vp)
332 	register struct tbl *vp;
333 {
334 	long num;
335 	int base;
336 
337 	base = getint(vp, &num);
338 	if (base == -1)
339 		/* XXX check calls - is error here ok by POSIX? */
340 		errorf("%s: bad number", str_val(vp));
341 	return num;
342 }
343 
344 /* set variable to string value */
345 void
346 setstr(vq, s)
347 	register struct tbl *vq;
348 	const char *s;
349 {
350 	if (!(vq->flag&INTEGER)) { /* string dest */
351 		if ((vq->flag&ALLOC)) {
352 			/* debugging */
353 			if (s >= vq->val.s
354 			    && s <= vq->val.s + strlen(vq->val.s))
355 				internal_errorf(TRUE,
356 				    "setstr: %s=%s: assigning to self",
357 				    vq->name, s);
358 			afree((void*)vq->val.s, vq->areap);
359 		}
360 		vq->flag &= ~(ISSET|ALLOC);
361 		vq->type = 0;
362 		if (s && (vq->flag & (UCASEV_AL|LCASEV|LJUST|RJUST)))
363 			s = formatstr(vq, s);
364 		if ((vq->flag&EXPORT))
365 			export(vq, s);
366 		else {
367 			vq->val.s = str_save(s, vq->areap);
368 			if (vq->val.s)		/* <sjg> don't lie */
369 				vq->flag |= ALLOC;
370 		}
371 	} else			/* integer dest */
372 		/* XXX is this correct? */
373 		v_evaluate(vq, s, FALSE);
374 	vq->flag |= ISSET;
375 	if ((vq->flag&SPECIAL))
376 		setspec(vq);
377 }
378 
379 /* set variable to integer */
380 void
381 setint(vq, n)
382 	register struct tbl *vq;
383 	long n;
384 {
385 	if (!(vq->flag&INTEGER)) {
386 		register struct tbl *vp = &vtemp;
387 		vp->flag = (ISSET|INTEGER);
388 		vp->type = 0;
389 		vp->areap = ATEMP;
390 		vp->val.i = n;
391 		setstr(vq, str_val(vp));
392 	} else
393 		vq->val.i = n;
394 	vq->flag |= ISSET;
395 	if ((vq->flag&SPECIAL))
396 		setspec(vq);
397 }
398 
399 int
400 getint(vp, nump)
401 	struct tbl *vp;
402 	long *nump;
403 {
404 	register char *s;
405 	register int c;
406 	int base, neg;
407 	int have_base = 0;
408 	long num;
409 
410 	if (vp->flag&SPECIAL)
411 		getspec(vp);
412 	/* XXX is it possible for ISSET to be set and val.s to be 0? */
413 	if (!(vp->flag&ISSET) || (!(vp->flag&INTEGER) && vp->val.s == NULL))
414 		return -1;
415 	if (vp->flag&INTEGER) {
416 		*nump = vp->val.i;
417 		return vp->type;
418 	}
419 	s = vp->val.s + vp->type;
420 	if (s == NULL)	/* redundent given initial test */
421 		s = null;
422 	base = 10;
423 	num = 0;
424 	neg = 0;
425 	for (c = *s++; c ; c = *s++) {
426 		if (c == '-') {
427 			neg++;
428 		} else if (c == '#') {
429 			base = (int) num;
430 			if (have_base || base < 2 || base > 36)
431 				return -1;
432 			num = 0;
433 			have_base = 1;
434 		} else if (letnum(c)) {
435 			if (isdigit(c))
436 				c -= '0';
437 			else if (islower(c))
438 				c -= 'a' - 10; /* todo: assumes ascii */
439 			else if (isupper(c))
440 				c -= 'A' - 10; /* todo: assumes ascii */
441 			else
442 				c = -1; /* _: force error */
443 			if (c < 0 || c >= base)
444 				return -1;
445 			num = num * base + c;
446 		} else
447 			return -1;
448 	}
449 	if (neg)
450 		num = -num;
451 	*nump = num;
452 	return base;
453 }
454 
455 /* convert variable vq to integer variable, setting its value from vp
456  * (vq and vp may be the same)
457  */
458 struct tbl *
459 setint_v(vq, vp)
460 	register struct tbl *vq, *vp;
461 {
462 	int base;
463 	long num;
464 
465 	if ((base = getint(vp, &num)) == -1)
466 		return NULL;
467 	if (!(vq->flag & INTEGER) && (vq->flag & ALLOC)) {
468 		vq->flag &= ~ALLOC;
469 		afree(vq->val.s, vq->areap);
470 	}
471 	vq->val.i = num;
472 	if (vq->type == 0) /* default base */
473 		vq->type = base;
474 	vq->flag |= ISSET|INTEGER;
475 	if (vq->flag&SPECIAL)
476 		setspec(vq);
477 	return vq;
478 }
479 
480 static char *
481 formatstr(vp, s)
482 	struct tbl *vp;
483 	const char *s;
484 {
485 	int olen, nlen;
486 	char *p, *q;
487 
488 	olen = strlen(s);
489 
490 	if (vp->flag & (RJUST|LJUST)) {
491 		if (!vp->u2.field)	/* default field width */
492 			vp->u2.field = olen;
493 		nlen = vp->u2.field;
494 	} else
495 		nlen = olen;
496 
497 	p = (char *) alloc(nlen + 1, ATEMP);
498 	if (vp->flag & (RJUST|LJUST)) {
499 		int slen;
500 
501 		if (vp->flag & RJUST) {
502 			const char *q = s + olen;
503 			/* strip trailing spaces (at&t ksh uses q[-1] == ' ') */
504 			while (q > s && isspace(q[-1]))
505 				--q;
506 			slen = q - s;
507 			if (slen > vp->u2.field) {
508 				s += slen - vp->u2.field;
509 				slen = vp->u2.field;
510 			}
511 			shf_snprintf(p, nlen + 1,
512 				((vp->flag & ZEROFIL) && digit(*s)) ?
513 					  "%0*s%.*s" : "%*s%.*s",
514 				vp->u2.field - slen, null, slen, s);
515 		} else {
516 			/* strip leading spaces/zeros */
517 			while (isspace(*s))
518 				s++;
519 			if (vp->flag & ZEROFIL)
520 				while (*s == '0')
521 					s++;
522 			shf_snprintf(p, nlen + 1, "%-*.*s",
523 				vp->u2.field, vp->u2.field, s);
524 		}
525 	} else
526 		memcpy(p, s, olen + 1);
527 
528 	if (vp->flag & UCASEV_AL) {
529 		for (q = p; *q; q++)
530 			if (islower(*q))
531 				*q = toupper(*q);
532 	} else if (vp->flag & LCASEV) {
533 		for (q = p; *q; q++)
534 			if (isupper(*q))
535 				*q = tolower(*q);
536 	}
537 
538 	return p;
539 }
540 
541 /*
542  * make vp->val.s be "name=value" for quick exporting.
543  */
544 static void
545 export(vp, val)
546 	register struct tbl *vp;
547 	const char *val;
548 {
549 	register char *xp;
550 	char *op = (vp->flag&ALLOC) ? vp->val.s : NULL;
551 	int namelen = strlen(vp->name);
552 	int vallen = strlen(val) + 1;
553 
554 	vp->flag |= ALLOC;
555 	xp = (char*)alloc(namelen + 1 + vallen, vp->areap);
556 	memcpy(vp->val.s = xp, vp->name, namelen);
557 	xp += namelen;
558 	*xp++ = '=';
559 	vp->type = xp - vp->val.s; /* offset to value */
560 	memcpy(xp, val, vallen);
561 	if (op != NULL)
562 		afree((void*)op, vp->areap);
563 }
564 
565 /*
566  * lookup variable (according to (set&LOCAL)),
567  * set its attributes (INTEGER, RDONLY, EXPORT, TRACE, LJUST, RJUST, ZEROFIL,
568  * LCASEV, UCASEV_AL), and optionally set its value if an assignment.
569  */
570 struct tbl *
571 typeset(var, set, clr, field, base)
572 	register const char *var;
573 	Tflag clr, set;
574 	int field, base;
575 {
576 	register struct tbl *vp;
577 	struct tbl *vpbase, *t;
578 	char *tvar;
579 	const char *val;
580 
581 	/* check for valid variable name, search for value */
582 	val = skip_varname(var, FALSE);
583 	if (val == var)
584 		return NULL;
585 	if (*val == '[') {
586 		int len;
587 
588 		len = array_ref_len(val);
589 		if (len == 0)
590 			return NULL;
591 		/* IMPORT is only used when the shell starts up and is
592 		 * setting up its environment.  Allow only simple array
593 		 * references at this time since parameter/command substitution
594 		 * is preformed on the [expression], which would be a major
595 		 * security hole.
596 		 */
597 		if (set & IMPORT) {
598 			int i;
599 			for (i = 1; i < len - 1; i++)
600 				if (!digit(val[i]))
601 					return NULL;
602 		}
603 		val += len;
604 	}
605 	if (*val == '=')
606 		tvar = str_nsave(var, val++ - var, ATEMP);
607 	else {
608 		/* Importing from original envirnment: must have an = */
609 		if (set & IMPORT)
610 			return NULL;
611 		tvar = (char *) var;
612 		val = NULL;
613 	}
614 
615 	/* Prevent typeset from creating a local PATH/ENV/SHELL */
616 	if (Flag(FRESTRICTED) && (strcmp(tvar, "PATH") == 0
617 				  || strcmp(tvar, "ENV") == 0
618 				  || strcmp(tvar, "SHELL") == 0))
619 		errorf("%s: restricted", tvar);
620 
621 	vp = (set&LOCAL) ? local(tvar, (set & LOCAL_COPY) ? TRUE : FALSE)
622 		: global(tvar);
623 	set &= ~(LOCAL|LOCAL_COPY);
624 
625 	vpbase = (vp->flag & ARRAY) ? global(arrayname(var)) : vp;
626 
627 	/* only allow export flag to be set.  at&t ksh allows any attribute to
628 	 * be changed, which means it can be truncated or modified
629 	 * (-L/-R/-Z/-i).
630 	 */
631 	if ((vpbase->flag&RDONLY)
632 	    && (val || clr || (set & ~EXPORT)))
633 		/* XXX check calls - is error here ok by POSIX? */
634 		errorf("%s: is read only", tvar);
635 	if (val)
636 		afree(tvar, ATEMP);
637 
638 	/* most calls are with set/clr == 0 */
639 	if (set | clr) {
640 		/* XXX if x[0] isn't set, there will be problems: need to have
641 		 * one copy of attributes for arrays...
642 		 */
643 		for (t = vpbase; t; t = t->u.array) {
644 			int fake_assign;
645 			char UNINITIALIZED(*s);
646 			char UNINITIALIZED(*free_me);
647 
648 			fake_assign = (t->flag & ISSET) && (!val || t != vp)
649 				      && ((set & (UCASEV_AL|LCASEV|LJUST|RJUST|ZEROFIL))
650 					  || ((t->flag & INTEGER) && (clr & INTEGER))
651 					  || (!(t->flag & INTEGER) && (set & INTEGER)));
652 			if (fake_assign) {
653 				if (t->flag & INTEGER) {
654 					s = str_val(t);
655 					free_me = (char *) 0;
656 				} else {
657 					s = t->val.s + t->type;
658 					free_me = (t->flag & ALLOC) ? t->val.s
659 								  : (char *) 0;
660 				}
661 				t->flag &= ~ALLOC;
662 			}
663 			if (!(t->flag & INTEGER) && (set & INTEGER)) {
664 				t->type = 0;
665 				t->flag &= ~ALLOC;
666 			}
667 			t->flag = (t->flag | set) & ~clr;
668 			/* Don't change base if assignment is to be done,
669 			 * in case assignment fails.
670 			 */
671 			if ((set & INTEGER) && base > 0 && (!val || t != vp))
672 				t->type = base;
673 			if (set & (LJUST|RJUST|ZEROFIL))
674 				t->u2.field = field;
675 			if (fake_assign) {
676 				setstr(t, s);
677 				if (free_me)
678 					afree((void *) free_me, t->areap);
679 			}
680 		}
681 	}
682 
683 	if (val != NULL) {
684 		if (vp->flag&INTEGER) {
685 			/* do not zero base before assignment */
686 			setstr(vp, val);
687 			/* Done after assignment to override default */
688 			if (base > 0)
689 				vp->type = base;
690 		} else
691 			setstr(vp, val);
692 	}
693 
694 	/* only x[0] is ever exported, so use vpbase */
695 	if ((vpbase->flag&EXPORT) && !(vpbase->flag&INTEGER)
696 	    && vpbase->type == 0)
697 		export(vpbase, (vpbase->flag&ISSET) ? vpbase->val.s : null);
698 
699 	return vp;
700 }
701 
702 /* Unset a variable.  array_ref is set if there was an array reference in
703  * the name lookup (eg, x[2]).
704  */
705 void
706 unset(vp, array_ref)
707 	register struct tbl *vp;
708 	int array_ref;
709 {
710 	if (vp->flag & ALLOC)
711 		afree((void*)vp->val.s, vp->areap);
712 	if ((vp->flag & ARRAY) && !array_ref) {
713 		struct tbl *a, *tmp;
714 
715 		/* Free up entire array */
716 		for (a = vp->u.array; a; ) {
717 			tmp = a;
718 			a = a->u.array;
719 			if (tmp->flag & ALLOC)
720 				afree((void *) tmp->val.s, tmp->areap);
721 			afree(tmp, tmp->areap);
722 		}
723 		vp->u.array = (struct tbl *) 0;
724 	}
725 	/* If foo[0] is being unset, the remainder of the array is kept... */
726 	vp->flag &= SPECIAL | (array_ref ? ARRAY|DEFINED : 0);
727 	if (vp->flag & SPECIAL)
728 		unsetspec(vp);	/* responsible for `unspecial'ing var */
729 }
730 
731 /* return a pointer to the first char past a legal variable name (returns the
732  * argument if there is no legal name, returns * a pointer to the terminating
733  * null if whole string is legal).
734  */
735 char *
736 skip_varname(s, aok)
737 	const char *s;
738 	int aok;
739 {
740 	int alen;
741 
742 	if (s && letter(*s)) {
743 		while (*++s && letnum(*s))
744 			;
745 		if (aok && *s == '[' && (alen = array_ref_len(s)))
746 			s += alen;
747 	}
748 	return (char *) s;
749 }
750 
751 /* Return a pointer to the first character past any legal variable name.  */
752 char *
753 skip_wdvarname(s, aok)
754 	const char *s;
755 	int aok;	/* skip array de-reference? */
756 {
757 	if (s[0] == CHAR && letter(s[1])) {
758 		do
759 			s += 2;
760 		while (s[0] == CHAR && letnum(s[1]));
761 		if (aok && s[0] == CHAR && s[1] == '[') {
762 			/* skip possible array de-reference */
763 			const char *p = s;
764 			char c;
765 			int depth = 0;
766 
767 			while (1) {
768 				if (p[0] != CHAR)
769 					break;
770 				c = p[1];
771 				p += 2;
772 				if (c == '[')
773 					depth++;
774 				else if (c == ']' && --depth == 0) {
775 					s = p;
776 					break;
777 				}
778 			}
779 		}
780 	}
781 	return (char *) s;
782 }
783 
784 /* Check if coded string s is a variable name */
785 int
786 is_wdvarname(s, aok)
787 	const char *s;
788 	int aok;
789 {
790 	char *p = skip_wdvarname(s, aok);
791 
792 	return p != s && p[0] == EOS;
793 }
794 
795 /* Check if coded string s is a variable assignment */
796 int
797 is_wdvarassign(s)
798 	const char *s;
799 {
800 	char *p = skip_wdvarname(s, TRUE);
801 
802 	return p != s && p[0] == CHAR && p[1] == '=';
803 }
804 
805 /*
806  * Make the exported environment from the exported names in the dictionary.
807  */
808 char **
809 makenv()
810 {
811 	struct block *l = e->loc;
812 	XPtrV env;
813 	register struct tbl *vp, **vpp;
814 	register int i;
815 
816 	XPinit(env, 64);
817 	for (l = e->loc; l != NULL; l = l->next)
818 		for (vpp = l->vars.tbls, i = l->vars.size; --i >= 0; )
819 			if ((vp = *vpp++) != NULL
820 			    && (vp->flag&(ISSET|EXPORT)) == (ISSET|EXPORT)) {
821 				register struct block *l2;
822 				register struct tbl *vp2;
823 				unsigned h = hash(vp->name);
824 
825 				/* unexport any redefined instances */
826 				for (l2 = l->next; l2 != NULL; l2 = l2->next) {
827 					vp2 = tsearch(&l2->vars, vp->name, h);
828 					if (vp2 != NULL)
829 						vp2->flag &= ~EXPORT;
830 				}
831 				if ((vp->flag&INTEGER)) {
832 					/* integer to string */
833 					char *val;
834 					val = str_val(vp);
835 					vp->flag &= ~INTEGER;
836 					setstr(vp, val);
837 				}
838 				XPput(env, vp->val.s);
839 			}
840 	XPput(env, NULL);
841 	return (char **) XPclose(env);
842 }
843 
844 /*
845  * handle special variables with side effects - PATH, SECONDS.
846  */
847 
848 /* Test if name is a special parameter */
849 static int
850 special(name)
851 	register const char * name;
852 {
853 	register struct tbl *tp;
854 
855 	tp = tsearch(&specials, name, hash(name));
856 	return tp ? tp->type : V_NONE;
857 }
858 
859 #ifdef KSH
860 static	time_t	seconds;		/* time SECONDS last set */
861 #endif /* KSH */
862 
863 static void
864 getspec(vp)
865 	register struct tbl *vp;
866 {
867 	switch (special(vp->name)) {
868 #ifdef KSH
869 	  case V_SECONDS:
870 		vp->flag &= ~SPECIAL;
871 		setint(vp, (long) (time((time_t *)0) - seconds));
872 		vp->flag |= SPECIAL;
873 		break;
874 	  case V_RANDOM:
875 		vp->flag &= ~SPECIAL;
876 		setint(vp, (long) (rand() & 0x7fff));
877 		vp->flag |= SPECIAL;
878 		break;
879 #endif /* KSH */
880 #ifdef HISTORY
881 	  case V_HISTSIZE:
882 		vp->flag &= ~SPECIAL;
883 		setint(vp, (long) histsize);
884 		vp->flag |= SPECIAL;
885 		break;
886 #endif /* HISTORY */
887 	}
888 }
889 
890 static void
891 setspec(vp)
892 	register struct tbl *vp;
893 {
894 	char *s;
895 
896 	switch (special(vp->name)) {
897 	  case V_PATH:
898 		path = str_val(vp);
899 		flushcom(1);	/* clear tracked aliases */
900 		break;
901 	  case V_IFS:
902 		setctypes(s = str_val(vp), C_IFS);
903 		ifs0 = *s;
904 		break;
905 	  case V_OPTIND:
906 		getopts_reset((int) intval(vp));
907 		break;
908 	  case V_POSIXLY_CORRECT:
909 		change_flag(FPOSIX, OF_SPECIAL, 1);
910 		break;
911 	  case V_TMPDIR:
912 		if (tmpdir) {
913 			afree(tmpdir, APERM);
914 			tmpdir = (char *) 0;
915 		}
916 		/* Use tmpdir iff it is an absolute path, is writable and
917 		 * searchable and is a directory...
918 		 */
919 		{
920 			struct stat statb;
921 			s = str_val(vp);
922 			if (ISABSPATH(s) && eaccess(s, W_OK|X_OK) == 0
923 			    && stat(s, &statb) == 0 && S_ISDIR(statb.st_mode))
924 				tmpdir = str_save(s, APERM);
925 		}
926 		break;
927 #ifdef HISTORY
928 	  case V_HISTSIZE:
929 		vp->flag &= ~SPECIAL;
930 		sethistsize((int) intval(vp));
931 		vp->flag |= SPECIAL;
932 		break;
933 	  case V_HISTFILE:
934 		sethistfile(str_val(vp));
935 		break;
936 #endif /* HISTORY */
937 #ifdef EDIT
938 	  case V_VISUAL:
939 		set_editmode(str_val(vp));
940 		break;
941 	  case V_EDITOR:
942 		if (!(global("VISUAL")->flag & ISSET))
943 			set_editmode(str_val(vp));
944 		break;
945 	  case V_COLUMNS:
946 		if ((x_cols = intval(vp)) <= MIN_COLS)
947 			x_cols = MIN_COLS;
948 		break;
949 #endif /* EDIT */
950 #ifdef KSH
951 	  case V_MAIL:
952 		mbset(str_val(vp));
953 		break;
954 	  case V_MAILPATH:
955 		mpset(str_val(vp));
956 		break;
957 	  case V_MAILCHECK:
958 		/* mail_check_set(intval(vp)); */
959 		break;
960 	  case V_RANDOM:
961 		vp->flag &= ~SPECIAL;
962 		srand((unsigned int)intval(vp));
963 		vp->flag |= SPECIAL;
964 		break;
965 	  case V_SECONDS:
966 		vp->flag &= ~SPECIAL;
967 		seconds = time((time_t*) 0) - intval(vp);
968 		vp->flag |= SPECIAL;
969 		break;
970 	  case V_TMOUT:
971 		/* at&t ksh seems to do this (only listen if integer) */
972 		if (vp->flag & INTEGER)
973 			ksh_tmout = vp->val.i >= 0 ? vp->val.i : 0;
974 		break;
975 #endif /* KSH */
976 	}
977 }
978 
979 static void
980 unsetspec(vp)
981 	register struct tbl *vp;
982 {
983 	switch (special(vp->name)) {
984 	  case V_PATH:
985 		path = def_path;
986 		flushcom(1);	/* clear tracked aliases */
987 		break;
988 	  case V_IFS:
989 		setctypes(" \t\n", C_IFS);
990 		ifs0 = ' ';
991 		break;
992 	  case V_TMPDIR:
993 		/* should not become unspecial */
994 		if (tmpdir) {
995 			afree(tmpdir, APERM);
996 			tmpdir = (char *) 0;
997 		}
998 		break;
999 #ifdef KSH
1000 	  case V_MAIL:
1001 		mbset((char *) 0);
1002 		break;
1003 	  case V_MAILPATH:
1004 		mpset((char *) 0);
1005 		break;
1006 	  case V_TMOUT:
1007 		/* at&t ksh doesn't do this. TMOUT becomes unspecial so
1008 		 * future assignments don't have effect.  Could be
1009 		 * useful (eg, after "TMOUT=60; unset TMOUT", user
1010 		 * can't get rid of the timeout...).  Should be handled
1011 		 * by generic unset code...
1012 		 */
1013 		ksh_tmout = 0;
1014 		break;
1015 #endif /* KSH */
1016 	  /* todo: generic action for specials (at&t says variables
1017 	   * lose their special meaning when unset but global() checks
1018 	   * the name of new vars to see if they are special)
1019 	   * 	lose meaning: _, ERRNO, LINENO, MAILCHECK,
1020 	   *		OPTARG, OPTIND, RANDOM, SECONDS, TMOUT.
1021 	   *	unknown: MAIL, MAILPATH, HISTSIZE, HISTFILE,
1022 	   *    no effect: IFS, COLUMNS, PATH, TMPDIR,
1023 	   *		VISUAL, EDITOR,
1024 	   *		POSIXLY_CORRECT (use set +o posix instead)
1025 	   */
1026 	}
1027 }
1028 
1029 /*
1030  * Search for (and possibly create) a table entry starting with
1031  * vp, indexed by val.
1032  */
1033 static struct tbl *
1034 arraysearch(vp, val)
1035 	struct tbl *vp;
1036 	int val;
1037 {
1038 	struct tbl *prev, *curr, *new;
1039 
1040 	vp->flag |= ARRAY|DEFINED;
1041 
1042 	/* The table entry is always [0] */
1043 	if (val == 0) {
1044 		vp->index = 0;
1045 		return vp;
1046 	}
1047 	prev = vp;
1048 	curr = vp->u.array;
1049 	while (curr && curr->index < val) {
1050 		prev = curr;
1051 		curr = curr->u.array;
1052 	}
1053 	if (curr && curr->index == val) {
1054 		if (curr->flag&ISSET)
1055 			return curr;
1056 		else
1057 			new = curr;
1058 	} else
1059 		new = (struct tbl *)alloc(sizeof(struct tbl)+strlen(vp->name)+1, vp->areap);
1060 	strcpy(new->name, vp->name);
1061 	new->flag = vp->flag & ~(ALLOC|DEFINED|ISSET|SPECIAL);
1062 	new->type = vp->type;
1063 	new->areap = vp->areap;
1064 	new->u2.field = vp->u2.field;
1065 	new->index = val;
1066 	if (curr != new) {		/* not reusing old array entry */
1067 		prev->u.array = new;
1068 		new->u.array = curr;
1069 	}
1070 	return new;
1071 }
1072 
1073 /* Return the length of an array reference (eg, [1+2]) - cp is assumed
1074  * to point to the open bracket.  Returns 0 if there is no matching closing
1075  * bracket.
1076  */
1077 int
1078 array_ref_len(cp)
1079 	const char *cp;
1080 {
1081 	const char *s = cp;
1082 	int c;
1083 	int depth = 0;
1084 
1085 	while ((c = *s++) && (c != ']' || --depth))
1086 		if (c == '[')
1087 			depth++;
1088 	if (!c)
1089 		return 0;
1090 	return s - cp;
1091 }
1092 
1093 /*
1094  * Make a copy of the base of an array name
1095  */
1096 char *
1097 arrayname(str)
1098 	const char *str;
1099 {
1100 	const char *p;
1101 
1102 	if ((p = strchr(str, '[')) == 0)
1103 		/* Shouldn't happen, but why worry? */
1104 		return (char *) str;
1105 
1106 	return str_nsave(str, p - str, ATEMP);
1107 }
1108 
1109 /* Set (or overwrite, if !reset) the array variable var to the values in vals.
1110  */
1111 void
1112 set_array(var, reset, vals)
1113 	const char *var;
1114 	int reset;
1115 	char **vals;
1116 {
1117 	struct tbl *vp, *vq;
1118 	int i;
1119 
1120 	/* to get local array, use "typeset foo; set -A foo" */
1121 	vp = global(var);
1122 
1123 	/* Note: at&t ksh allows set -A but not set +A of a read-only var */
1124 	if ((vp->flag&RDONLY))
1125 		errorf("%s: is read only", var);
1126 	/* This code is quite non-optimal */
1127 	if (reset > 0)
1128 		/* trash existing values and attributes */
1129 		unset(vp, 0);
1130 	/* todo: would be nice for assignment to completely succeed or
1131 	 * completely fail.  Only really effects integer arrays:
1132 	 * evaluation of some of vals[] may fail...
1133 	 */
1134 	for (i = 0; vals[i]; i++) {
1135 		vq = arraysearch(vp, i);
1136 		setstr(vq, vals[i]);
1137 	}
1138 }
1139