xref: /freebsd/bin/sh/var.c (revision 195ebc7e9e4b129de810833791a19dfb4349d6a9) 
1 /*-
2  * Copyright (c) 1991, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Kenneth Almquist.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 4. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 #ifndef lint
34 #if 0
35 static char sccsid[] = "@(#)var.c	8.3 (Berkeley) 5/4/95";
36 #endif
37 #endif /* not lint */
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40 
41 #include <unistd.h>
42 #include <stdlib.h>
43 #include <paths.h>
44 
45 /*
46  * Shell variables.
47  */
48 
49 #include <locale.h>
50 
51 #include "shell.h"
52 #include "output.h"
53 #include "expand.h"
54 #include "nodes.h"	/* for other headers */
55 #include "eval.h"	/* defines cmdenviron */
56 #include "exec.h"
57 #include "syntax.h"
58 #include "options.h"
59 #include "mail.h"
60 #include "var.h"
61 #include "memalloc.h"
62 #include "error.h"
63 #include "mystring.h"
64 #include "parser.h"
65 #ifndef NO_HISTORY
66 #include "myhistedit.h"
67 #endif
68 
69 
70 #define VTABSIZE 39
71 
72 
73 struct varinit {
74 	struct var *var;
75 	int flags;
76 	char *text;
77 	void (*func)(const char *);
78 };
79 
80 
81 #ifndef NO_HISTORY
82 struct var vhistsize;
83 #endif
84 struct var vifs;
85 struct var vmail;
86 struct var vmpath;
87 struct var vpath;
88 struct var vppid;
89 struct var vps1;
90 struct var vps2;
91 struct var vps4;
92 struct var vvers;
93 STATIC struct var voptind;
94 
95 STATIC const struct varinit varinit[] = {
96 #ifndef NO_HISTORY
97 	{ &vhistsize,	VSTRFIXED|VTEXTFIXED|VUNSET,	"HISTSIZE=",
98 	  sethistsize },
99 #endif
100 	{ &vifs,	VSTRFIXED|VTEXTFIXED,		"IFS= \t\n",
101 	  NULL },
102 	{ &vmail,	VSTRFIXED|VTEXTFIXED|VUNSET,	"MAIL=",
103 	  NULL },
104 	{ &vmpath,	VSTRFIXED|VTEXTFIXED|VUNSET,	"MAILPATH=",
105 	  NULL },
106 	{ &vpath,	VSTRFIXED|VTEXTFIXED,		"PATH=" _PATH_DEFPATH,
107 	  changepath },
108 	{ &vppid,	VSTRFIXED|VTEXTFIXED|VUNSET,	"PPID=",
109 	  NULL },
110 	/*
111 	 * vps1 depends on uid
112 	 */
113 	{ &vps2,	VSTRFIXED|VTEXTFIXED,		"PS2=> ",
114 	  NULL },
115 	{ &vps4,	VSTRFIXED|VTEXTFIXED,		"PS4=+ ",
116 	  NULL },
117 	{ &voptind,	VSTRFIXED|VTEXTFIXED,		"OPTIND=1",
118 	  getoptsreset },
119 	{ NULL,	0,				NULL,
120 	  NULL }
121 };
122 
123 STATIC struct var *vartab[VTABSIZE];
124 
125 STATIC struct var **hashvar(char *);
126 STATIC int varequal(char *, char *);
127 STATIC int localevar(char *);
128 
129 /*
130  * Initialize the variable symbol tables and import the environment.
131  */
132 
133 #ifdef mkinit
134 INCLUDE "var.h"
135 INIT {
136 	char **envp;
137 	extern char **environ;
138 
139 	initvar();
140 	for (envp = environ ; *envp ; envp++) {
141 		if (strchr(*envp, '=')) {
142 			setvareq(*envp, VEXPORT|VTEXTFIXED);
143 		}
144 	}
145 }
146 #endif
147 
148 
149 /*
150  * This routine initializes the builtin variables.  It is called when the
151  * shell is initialized and again when a shell procedure is spawned.
152  */
153 
154 void
155 initvar(void)
156 {
157 	char ppid[20];
158 	const struct varinit *ip;
159 	struct var *vp;
160 	struct var **vpp;
161 
162 	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
163 		if ((vp->flags & VEXPORT) == 0) {
164 			vpp = hashvar(ip->text);
165 			vp->next = *vpp;
166 			*vpp = vp;
167 			vp->text = ip->text;
168 			vp->flags = ip->flags;
169 			vp->func = ip->func;
170 		}
171 	}
172 	/*
173 	 * PS1 depends on uid
174 	 */
175 	if ((vps1.flags & VEXPORT) == 0) {
176 		vpp = hashvar("PS1=");
177 		vps1.next = *vpp;
178 		*vpp = &vps1;
179 		vps1.text = geteuid() ? "PS1=$ " : "PS1=# ";
180 		vps1.flags = VSTRFIXED|VTEXTFIXED;
181 	}
182 	if ((vppid.flags & VEXPORT) == 0) {
183 		fmtstr(ppid, sizeof(ppid), "%d", (int)getppid());
184 		setvarsafe("PPID", ppid, 0);
185 	}
186 }
187 
188 /*
189  * Safe version of setvar, returns 1 on success 0 on failure.
190  */
191 
192 int
193 setvarsafe(char *name, char *val, int flags)
194 {
195 	struct jmploc jmploc;
196 	struct jmploc *volatile savehandler = handler;
197 	int err = 0;
198 #ifdef __GNUC__
199 	/* Avoid longjmp clobbering */
200 	(void) &err;
201 #endif
202 
203 	if (setjmp(jmploc.loc))
204 		err = 1;
205 	else {
206 		handler = &jmploc;
207 		setvar(name, val, flags);
208 	}
209 	handler = savehandler;
210 	return err;
211 }
212 
213 /*
214  * Set the value of a variable.  The flags argument is stored with the
215  * flags of the variable.  If val is NULL, the variable is unset.
216  */
217 
218 void
219 setvar(char *name, char *val, int flags)
220 {
221 	char *p, *q;
222 	int len;
223 	int namelen;
224 	char *nameeq;
225 	int isbad;
226 
227 	isbad = 0;
228 	p = name;
229 	if (! is_name(*p))
230 		isbad = 1;
231 	p++;
232 	for (;;) {
233 		if (! is_in_name(*p)) {
234 			if (*p == '\0' || *p == '=')
235 				break;
236 			isbad = 1;
237 		}
238 		p++;
239 	}
240 	namelen = p - name;
241 	if (isbad)
242 		error("%.*s: bad variable name", namelen, name);
243 	len = namelen + 2;		/* 2 is space for '=' and '\0' */
244 	if (val == NULL) {
245 		flags |= VUNSET;
246 	} else {
247 		len += strlen(val);
248 	}
249 	p = nameeq = ckmalloc(len);
250 	q = name;
251 	while (--namelen >= 0)
252 		*p++ = *q++;
253 	*p++ = '=';
254 	*p = '\0';
255 	if (val)
256 		scopy(val, p);
257 	setvareq(nameeq, flags);
258 }
259 
260 STATIC int
261 localevar(char *s)
262 {
263 	static char *lnames[7] = {
264 		"ALL", "COLLATE", "CTYPE", "MONETARY",
265 		"NUMERIC", "TIME", NULL
266 	};
267 	char **ss;
268 
269 	if (*s != 'L')
270 		return 0;
271 	if (varequal(s + 1, "ANG"))
272 		return 1;
273 	if (strncmp(s + 1, "C_", 2) != 0)
274 		return 0;
275 	for (ss = lnames; *ss ; ss++)
276 		if (varequal(s + 3, *ss))
277 			return 1;
278 	return 0;
279 }
280 
281 
282 /*
283  * Sets/unsets an environment variable from a pointer that may actually be a
284  * pointer into environ where the string should not be manipulated.
285  */
286 static void
287 change_env(char *s, int set)
288 {
289 	char *eqp;
290 	char *ss;
291 
292 	ss = savestr(s);
293 	if ((eqp = strchr(ss, '=')) != NULL)
294 		*eqp = '\0';
295 	if (set && eqp != NULL)
296 		(void) setenv(ss, eqp + 1, 1);
297 	else
298 		(void) unsetenv(ss);
299 	ckfree(ss);
300 
301 	return;
302 }
303 
304 
305 /*
306  * Same as setvar except that the variable and value are passed in
307  * the first argument as name=value.  Since the first argument will
308  * be actually stored in the table, it should not be a string that
309  * will go away.
310  */
311 
312 void
313 setvareq(char *s, int flags)
314 {
315 	struct var *vp, **vpp;
316 	int len;
317 
318 	if (aflag)
319 		flags |= VEXPORT;
320 	vpp = hashvar(s);
321 	for (vp = *vpp ; vp ; vp = vp->next) {
322 		if (varequal(s, vp->text)) {
323 			if (vp->flags & VREADONLY) {
324 				len = strchr(s, '=') - s;
325 				error("%.*s: is read only", len, s);
326 			}
327 			INTOFF;
328 
329 			if (vp->func && (flags & VNOFUNC) == 0)
330 				(*vp->func)(strchr(s, '=') + 1);
331 
332 			if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
333 				ckfree(vp->text);
334 
335 			vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
336 			vp->flags |= flags;
337 			vp->text = s;
338 
339 			/*
340 			 * We could roll this to a function, to handle it as
341 			 * a regular variable function callback, but why bother?
342 			 */
343 			if (vp == &vmpath || (vp == &vmail && ! mpathset()))
344 				chkmail(1);
345 			if ((vp->flags & VEXPORT) && localevar(s)) {
346 				change_env(s, 1);
347 				(void) setlocale(LC_ALL, "");
348 			}
349 			INTON;
350 			return;
351 		}
352 	}
353 	/* not found */
354 	vp = ckmalloc(sizeof (*vp));
355 	vp->flags = flags;
356 	vp->text = s;
357 	vp->next = *vpp;
358 	vp->func = NULL;
359 	INTOFF;
360 	*vpp = vp;
361 	if ((vp->flags & VEXPORT) && localevar(s)) {
362 		change_env(s, 1);
363 		(void) setlocale(LC_ALL, "");
364 	}
365 	INTON;
366 }
367 
368 
369 
370 /*
371  * Process a linked list of variable assignments.
372  */
373 
374 void
375 listsetvar(struct strlist *list)
376 {
377 	struct strlist *lp;
378 
379 	INTOFF;
380 	for (lp = list ; lp ; lp = lp->next) {
381 		setvareq(savestr(lp->text), 0);
382 	}
383 	INTON;
384 }
385 
386 
387 
388 /*
389  * Find the value of a variable.  Returns NULL if not set.
390  */
391 
392 char *
393 lookupvar(char *name)
394 {
395 	struct var *v;
396 
397 	for (v = *hashvar(name) ; v ; v = v->next) {
398 		if (varequal(v->text, name)) {
399 			if (v->flags & VUNSET)
400 				return NULL;
401 			return strchr(v->text, '=') + 1;
402 		}
403 	}
404 	return NULL;
405 }
406 
407 
408 
409 /*
410  * Search the environment of a builtin command.  If the second argument
411  * is nonzero, return the value of a variable even if it hasn't been
412  * exported.
413  */
414 
415 char *
416 bltinlookup(char *name, int doall)
417 {
418 	struct strlist *sp;
419 	struct var *v;
420 
421 	for (sp = cmdenviron ; sp ; sp = sp->next) {
422 		if (varequal(sp->text, name))
423 			return strchr(sp->text, '=') + 1;
424 	}
425 	for (v = *hashvar(name) ; v ; v = v->next) {
426 		if (varequal(v->text, name)) {
427 			if ((v->flags & VUNSET)
428 			 || (!doall && (v->flags & VEXPORT) == 0))
429 				return NULL;
430 			return strchr(v->text, '=') + 1;
431 		}
432 	}
433 	return NULL;
434 }
435 
436 
437 
438 /*
439  * Generate a list of exported variables.  This routine is used to construct
440  * the third argument to execve when executing a program.
441  */
442 
443 char **
444 environment(void)
445 {
446 	int nenv;
447 	struct var **vpp;
448 	struct var *vp;
449 	char **env, **ep;
450 
451 	nenv = 0;
452 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
453 		for (vp = *vpp ; vp ; vp = vp->next)
454 			if (vp->flags & VEXPORT)
455 				nenv++;
456 	}
457 	ep = env = stalloc((nenv + 1) * sizeof *env);
458 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
459 		for (vp = *vpp ; vp ; vp = vp->next)
460 			if (vp->flags & VEXPORT)
461 				*ep++ = vp->text;
462 	}
463 	*ep = NULL;
464 	return env;
465 }
466 
467 
468 /*
469  * Called when a shell procedure is invoked to clear out nonexported
470  * variables.  It is also necessary to reallocate variables of with
471  * VSTACK set since these are currently allocated on the stack.
472  */
473 
474 #ifdef mkinit
475 MKINIT void shprocvar(void);
476 
477 SHELLPROC {
478 	shprocvar();
479 }
480 #endif
481 
482 void
483 shprocvar(void)
484 {
485 	struct var **vpp;
486 	struct var *vp, **prev;
487 
488 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
489 		for (prev = vpp ; (vp = *prev) != NULL ; ) {
490 			if ((vp->flags & VEXPORT) == 0) {
491 				*prev = vp->next;
492 				if ((vp->flags & VTEXTFIXED) == 0)
493 					ckfree(vp->text);
494 				if ((vp->flags & VSTRFIXED) == 0)
495 					ckfree(vp);
496 			} else {
497 				if (vp->flags & VSTACK) {
498 					vp->text = savestr(vp->text);
499 					vp->flags &=~ VSTACK;
500 				}
501 				prev = &vp->next;
502 			}
503 		}
504 	}
505 	initvar();
506 }
507 
508 
509 static int
510 var_compare(const void *a, const void *b)
511 {
512 	const char *const *sa, *const *sb;
513 
514 	sa = a;
515 	sb = b;
516 	/*
517 	 * This compares two var=value strings which creates a different
518 	 * order from what you would probably expect.  POSIX is somewhat
519 	 * ambiguous on what should be sorted exactly.
520 	 */
521 	return strcoll(*sa, *sb);
522 }
523 
524 
525 /*
526  * Command to list all variables which are set.  Currently this command
527  * is invoked from the set command when the set command is called without
528  * any variables.
529  */
530 
531 int
532 showvarscmd(int argc __unused, char **argv __unused)
533 {
534 	struct var **vpp;
535 	struct var *vp;
536 	const char *s;
537 	const char **vars;
538 	int i, n;
539 
540 	/*
541 	 * POSIX requires us to sort the variables.
542 	 */
543 	n = 0;
544 	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
545 		for (vp = *vpp; vp; vp = vp->next) {
546 			if (!(vp->flags & VUNSET))
547 				n++;
548 		}
549 	}
550 
551 	INTON;
552 	vars = ckmalloc(n * sizeof(*vars));
553 	i = 0;
554 	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
555 		for (vp = *vpp; vp; vp = vp->next) {
556 			if (!(vp->flags & VUNSET))
557 				vars[i++] = vp->text;
558 		}
559 	}
560 
561 	qsort(vars, n, sizeof(*vars), var_compare);
562 	for (i = 0; i < n; i++) {
563 		for (s = vars[i]; *s != '='; s++)
564 			out1c(*s);
565 		out1c('=');
566 		out1qstr(s + 1);
567 		out1c('\n');
568 	}
569 	ckfree(vars);
570 	INTOFF;
571 
572 	return 0;
573 }
574 
575 
576 
577 /*
578  * The export and readonly commands.
579  */
580 
581 int
582 exportcmd(int argc, char **argv)
583 {
584 	struct var **vpp;
585 	struct var *vp;
586 	char *name;
587 	char *p;
588 	char *cmdname;
589 	int ch, values;
590 	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
591 
592 	cmdname = argv[0];
593 	optreset = optind = 1;
594 	opterr = 0;
595 	values = 0;
596 	while ((ch = getopt(argc, argv, "p")) != -1) {
597 		switch (ch) {
598 		case 'p':
599 			values = 1;
600 			break;
601 		case '?':
602 		default:
603 			error("unknown option: -%c", optopt);
604 		}
605 	}
606 	argc -= optind;
607 	argv += optind;
608 
609 	if (values && argc != 0)
610 		error("-p requires no arguments");
611 	listsetvar(cmdenviron);
612 	if (argc != 0) {
613 		while ((name = *argv++) != NULL) {
614 			if ((p = strchr(name, '=')) != NULL) {
615 				p++;
616 			} else {
617 				vpp = hashvar(name);
618 				for (vp = *vpp ; vp ; vp = vp->next) {
619 					if (varequal(vp->text, name)) {
620 
621 						vp->flags |= flag;
622 						if ((vp->flags & VEXPORT) && localevar(vp->text)) {
623 							change_env(vp->text, 1);
624 							(void) setlocale(LC_ALL, "");
625 						}
626 						goto found;
627 					}
628 				}
629 			}
630 			setvar(name, p, flag);
631 found:;
632 		}
633 	} else {
634 		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
635 			for (vp = *vpp ; vp ; vp = vp->next) {
636 				if (vp->flags & flag) {
637 					if (values) {
638 						out1str(cmdname);
639 						out1c(' ');
640 					}
641 					for (p = vp->text ; *p != '=' ; p++)
642 						out1c(*p);
643 					if (values && !(vp->flags & VUNSET)) {
644 						out1c('=');
645 						out1qstr(p + 1);
646 					}
647 					out1c('\n');
648 				}
649 			}
650 		}
651 	}
652 	return 0;
653 }
654 
655 
656 /*
657  * The "local" command.
658  */
659 
660 int
661 localcmd(int argc __unused, char **argv __unused)
662 {
663 	char *name;
664 
665 	if (! in_function())
666 		error("Not in a function");
667 	while ((name = *argptr++) != NULL) {
668 		mklocal(name);
669 	}
670 	return 0;
671 }
672 
673 
674 /*
675  * Make a variable a local variable.  When a variable is made local, it's
676  * value and flags are saved in a localvar structure.  The saved values
677  * will be restored when the shell function returns.  We handle the name
678  * "-" as a special case.
679  */
680 
681 void
682 mklocal(char *name)
683 {
684 	struct localvar *lvp;
685 	struct var **vpp;
686 	struct var *vp;
687 
688 	INTOFF;
689 	lvp = ckmalloc(sizeof (struct localvar));
690 	if (name[0] == '-' && name[1] == '\0') {
691 		lvp->text = ckmalloc(sizeof optlist);
692 		memcpy(lvp->text, optlist, sizeof optlist);
693 		vp = NULL;
694 	} else {
695 		vpp = hashvar(name);
696 		for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next);
697 		if (vp == NULL) {
698 			if (strchr(name, '='))
699 				setvareq(savestr(name), VSTRFIXED);
700 			else
701 				setvar(name, NULL, VSTRFIXED);
702 			vp = *vpp;	/* the new variable */
703 			lvp->text = NULL;
704 			lvp->flags = VUNSET;
705 		} else {
706 			lvp->text = vp->text;
707 			lvp->flags = vp->flags;
708 			vp->flags |= VSTRFIXED|VTEXTFIXED;
709 			if (strchr(name, '='))
710 				setvareq(savestr(name), 0);
711 		}
712 	}
713 	lvp->vp = vp;
714 	lvp->next = localvars;
715 	localvars = lvp;
716 	INTON;
717 }
718 
719 
720 /*
721  * Called after a function returns.
722  */
723 
724 void
725 poplocalvars(void)
726 {
727 	struct localvar *lvp;
728 	struct var *vp;
729 
730 	while ((lvp = localvars) != NULL) {
731 		localvars = lvp->next;
732 		vp = lvp->vp;
733 		if (vp == NULL) {	/* $- saved */
734 			memcpy(optlist, lvp->text, sizeof optlist);
735 			ckfree(lvp->text);
736 		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
737 			(void)unsetvar(vp->text);
738 		} else {
739 			if ((vp->flags & VTEXTFIXED) == 0)
740 				ckfree(vp->text);
741 			vp->flags = lvp->flags;
742 			vp->text = lvp->text;
743 		}
744 		ckfree(lvp);
745 	}
746 }
747 
748 
749 int
750 setvarcmd(int argc, char **argv)
751 {
752 	if (argc <= 2)
753 		return unsetcmd(argc, argv);
754 	else if (argc == 3)
755 		setvar(argv[1], argv[2], 0);
756 	else
757 		error("List assignment not implemented");
758 	return 0;
759 }
760 
761 
762 /*
763  * The unset builtin command.  We unset the function before we unset the
764  * variable to allow a function to be unset when there is a readonly variable
765  * with the same name.
766  */
767 
768 int
769 unsetcmd(int argc __unused, char **argv __unused)
770 {
771 	char **ap;
772 	int i;
773 	int flg_func = 0;
774 	int flg_var = 0;
775 	int ret = 0;
776 
777 	while ((i = nextopt("vf")) != '\0') {
778 		if (i == 'f')
779 			flg_func = 1;
780 		else
781 			flg_var = 1;
782 	}
783 	if (flg_func == 0 && flg_var == 0)
784 		flg_var = 1;
785 
786 	for (ap = argptr; *ap ; ap++) {
787 		if (flg_func)
788 			ret |= unsetfunc(*ap);
789 		if (flg_var)
790 			ret |= unsetvar(*ap);
791 	}
792 	return ret;
793 }
794 
795 
796 /*
797  * Unset the specified variable.
798  */
799 
800 int
801 unsetvar(char *s)
802 {
803 	struct var **vpp;
804 	struct var *vp;
805 
806 	vpp = hashvar(s);
807 	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
808 		if (varequal(vp->text, s)) {
809 			if (vp->flags & VREADONLY)
810 				return (1);
811 			INTOFF;
812 			if (*(strchr(vp->text, '=') + 1) != '\0')
813 				setvar(s, nullstr, 0);
814 			if ((vp->flags & VEXPORT) && localevar(vp->text)) {
815 				change_env(s, 0);
816 				setlocale(LC_ALL, "");
817 			}
818 			vp->flags &= ~VEXPORT;
819 			vp->flags |= VUNSET;
820 			if ((vp->flags & VSTRFIXED) == 0) {
821 				if ((vp->flags & VTEXTFIXED) == 0)
822 					ckfree(vp->text);
823 				*vpp = vp->next;
824 				ckfree(vp);
825 			}
826 			INTON;
827 			return (0);
828 		}
829 	}
830 
831 	return (0);
832 }
833 
834 
835 
836 /*
837  * Find the appropriate entry in the hash table from the name.
838  */
839 
840 STATIC struct var **
841 hashvar(char *p)
842 {
843 	unsigned int hashval;
844 
845 	hashval = ((unsigned char) *p) << 4;
846 	while (*p && *p != '=')
847 		hashval += (unsigned char) *p++;
848 	return &vartab[hashval % VTABSIZE];
849 }
850 
851 
852 
853 /*
854  * Returns true if the two strings specify the same varable.  The first
855  * variable name is terminated by '='; the second may be terminated by
856  * either '=' or '\0'.
857  */
858 
859 STATIC int
860 varequal(char *p, char *q)
861 {
862 	while (*p == *q++) {
863 		if (*p++ == '=')
864 			return 1;
865 	}
866 	if (*p == '=' && *(q - 1) == '\0')
867 		return 1;
868 	return 0;
869 }
870