xref: /freebsd/bin/sh/var.c (revision 9fd69f37d28cfd7438cac3eeb45fe9dd46b4d7dd) 
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 	const 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,	VUNSET,				"HISTSIZE=",
98 	  sethistsize },
99 #endif
100 	{ &vifs,	0,				"IFS= \t\n",
101 	  NULL },
102 	{ &vmail,	VUNSET,				"MAIL=",
103 	  NULL },
104 	{ &vmpath,	VUNSET,				"MAILPATH=",
105 	  NULL },
106 	{ &vpath,	0,				"PATH=" _PATH_DEFPATH,
107 	  changepath },
108 	{ &vppid,	VUNSET,				"PPID=",
109 	  NULL },
110 	/*
111 	 * vps1 depends on uid
112 	 */
113 	{ &vps2,	0,				"PS2=> ",
114 	  NULL },
115 	{ &vps4,	0,				"PS4=+ ",
116 	  NULL },
117 	{ &voptind,	0,				"OPTIND=1",
118 	  getoptsreset },
119 	{ NULL,	0,				NULL,
120 	  NULL }
121 };
122 
123 STATIC struct var *vartab[VTABSIZE];
124 
125 STATIC struct var **hashvar(const char *);
126 STATIC int varequal(const char *, const char *);
127 STATIC int localevar(const char *);
128 
129 /*
130  * Initialize the variable symbol tables and import the environment.
131  */
132 
133 #ifdef mkinit
134 INCLUDE "var.h"
135 MKINIT char **environ;
136 INIT {
137 	char **envp;
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 = __DECONST(char *, ip->text);
168 			vp->flags = ip->flags | VSTRFIXED | VTEXTFIXED;
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 = __DECONST(char *, 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(const char *name, const char *val, int flags)
194 {
195 	struct jmploc jmploc;
196 	struct jmploc *const savehandler = handler;
197 	int err = 0;
198 	int inton;
199 
200 	inton = is_int_on();
201 	if (setjmp(jmploc.loc))
202 		err = 1;
203 	else {
204 		handler = &jmploc;
205 		setvar(name, val, flags);
206 	}
207 	handler = savehandler;
208 	SETINTON(inton);
209 	return err;
210 }
211 
212 /*
213  * Set the value of a variable.  The flags argument is stored with the
214  * flags of the variable.  If val is NULL, the variable is unset.
215  */
216 
217 void
218 setvar(const char *name, const char *val, int flags)
219 {
220 	const char *p;
221 	int len;
222 	int namelen;
223 	char *nameeq;
224 	int isbad;
225 
226 	isbad = 0;
227 	p = name;
228 	if (! is_name(*p))
229 		isbad = 1;
230 	p++;
231 	for (;;) {
232 		if (! is_in_name(*p)) {
233 			if (*p == '\0' || *p == '=')
234 				break;
235 			isbad = 1;
236 		}
237 		p++;
238 	}
239 	namelen = p - name;
240 	if (isbad)
241 		error("%.*s: bad variable name", namelen, name);
242 	len = namelen + 2;		/* 2 is space for '=' and '\0' */
243 	if (val == NULL) {
244 		flags |= VUNSET;
245 	} else {
246 		len += strlen(val);
247 	}
248 	nameeq = ckmalloc(len);
249 	memcpy(nameeq, name, namelen);
250 	nameeq[namelen] = '=';
251 	if (val)
252 		scopy(val, nameeq + namelen + 1);
253 	else
254 		nameeq[namelen + 1] = '\0';
255 	setvareq(nameeq, flags);
256 }
257 
258 STATIC int
259 localevar(const char *s)
260 {
261 	static const char *lnames[7] = {
262 		"ALL", "COLLATE", "CTYPE", "MONETARY",
263 		"NUMERIC", "TIME", NULL
264 	};
265 	const char **ss;
266 
267 	if (*s != 'L')
268 		return 0;
269 	if (varequal(s + 1, "ANG"))
270 		return 1;
271 	if (strncmp(s + 1, "C_", 2) != 0)
272 		return 0;
273 	for (ss = lnames; *ss ; ss++)
274 		if (varequal(s + 3, *ss))
275 			return 1;
276 	return 0;
277 }
278 
279 
280 /*
281  * Sets/unsets an environment variable from a pointer that may actually be a
282  * pointer into environ where the string should not be manipulated.
283  */
284 static void
285 change_env(const char *s, int set)
286 {
287 	char *eqp;
288 	char *ss;
289 
290 	ss = savestr(s);
291 	if ((eqp = strchr(ss, '=')) != NULL)
292 		*eqp = '\0';
293 	if (set && eqp != NULL)
294 		(void) setenv(ss, eqp + 1, 1);
295 	else
296 		(void) unsetenv(ss);
297 	ckfree(ss);
298 
299 	return;
300 }
301 
302 
303 /*
304  * Same as setvar except that the variable and value are passed in
305  * the first argument as name=value.  Since the first argument will
306  * be actually stored in the table, it should not be a string that
307  * will go away.
308  */
309 
310 void
311 setvareq(char *s, int flags)
312 {
313 	struct var *vp, **vpp;
314 	int len;
315 
316 	if (aflag)
317 		flags |= VEXPORT;
318 	vpp = hashvar(s);
319 	for (vp = *vpp ; vp ; vp = vp->next) {
320 		if (varequal(s, vp->text)) {
321 			if (vp->flags & VREADONLY) {
322 				len = strchr(s, '=') - s;
323 				error("%.*s: is read only", len, s);
324 			}
325 			INTOFF;
326 
327 			if (vp->func && (flags & VNOFUNC) == 0)
328 				(*vp->func)(strchr(s, '=') + 1);
329 
330 			if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
331 				ckfree(vp->text);
332 
333 			vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
334 			vp->flags |= flags;
335 			vp->text = s;
336 
337 			/*
338 			 * We could roll this to a function, to handle it as
339 			 * a regular variable function callback, but why bother?
340 			 *
341 			 * Note: this assumes iflag is not set to 1 initially.
342 			 * As part of init(), this is called before arguments
343 			 * are looked at.
344 			 */
345 			if ((vp == &vmpath || (vp == &vmail && ! mpathset())) &&
346 			    iflag == 1)
347 				chkmail(1);
348 			if ((vp->flags & VEXPORT) && localevar(s)) {
349 				change_env(s, 1);
350 				(void) setlocale(LC_ALL, "");
351 			}
352 			INTON;
353 			return;
354 		}
355 	}
356 	/* not found */
357 	vp = ckmalloc(sizeof (*vp));
358 	vp->flags = flags;
359 	vp->text = s;
360 	vp->next = *vpp;
361 	vp->func = NULL;
362 	INTOFF;
363 	*vpp = vp;
364 	if ((vp->flags & VEXPORT) && localevar(s)) {
365 		change_env(s, 1);
366 		(void) setlocale(LC_ALL, "");
367 	}
368 	INTON;
369 }
370 
371 
372 
373 /*
374  * Process a linked list of variable assignments.
375  */
376 
377 void
378 listsetvar(struct strlist *list)
379 {
380 	struct strlist *lp;
381 
382 	INTOFF;
383 	for (lp = list ; lp ; lp = lp->next) {
384 		setvareq(savestr(lp->text), 0);
385 	}
386 	INTON;
387 }
388 
389 
390 
391 /*
392  * Find the value of a variable.  Returns NULL if not set.
393  */
394 
395 char *
396 lookupvar(const char *name)
397 {
398 	struct var *v;
399 
400 	for (v = *hashvar(name) ; v ; v = v->next) {
401 		if (varequal(v->text, name)) {
402 			if (v->flags & VUNSET)
403 				return NULL;
404 			return strchr(v->text, '=') + 1;
405 		}
406 	}
407 	return NULL;
408 }
409 
410 
411 
412 /*
413  * Search the environment of a builtin command.  If the second argument
414  * is nonzero, return the value of a variable even if it hasn't been
415  * exported.
416  */
417 
418 char *
419 bltinlookup(const char *name, int doall)
420 {
421 	struct strlist *sp;
422 	struct var *v;
423 
424 	for (sp = cmdenviron ; sp ; sp = sp->next) {
425 		if (varequal(sp->text, name))
426 			return strchr(sp->text, '=') + 1;
427 	}
428 	for (v = *hashvar(name) ; v ; v = v->next) {
429 		if (varequal(v->text, name)) {
430 			if ((v->flags & VUNSET)
431 			 || (!doall && (v->flags & VEXPORT) == 0))
432 				return NULL;
433 			return strchr(v->text, '=') + 1;
434 		}
435 	}
436 	return NULL;
437 }
438 
439 
440 
441 /*
442  * Generate a list of exported variables.  This routine is used to construct
443  * the third argument to execve when executing a program.
444  */
445 
446 char **
447 environment(void)
448 {
449 	int nenv;
450 	struct var **vpp;
451 	struct var *vp;
452 	char **env, **ep;
453 
454 	nenv = 0;
455 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
456 		for (vp = *vpp ; vp ; vp = vp->next)
457 			if (vp->flags & VEXPORT)
458 				nenv++;
459 	}
460 	ep = env = stalloc((nenv + 1) * sizeof *env);
461 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
462 		for (vp = *vpp ; vp ; vp = vp->next)
463 			if (vp->flags & VEXPORT)
464 				*ep++ = vp->text;
465 	}
466 	*ep = NULL;
467 	return env;
468 }
469 
470 
471 /*
472  * Called when a shell procedure is invoked to clear out nonexported
473  * variables.  It is also necessary to reallocate variables of with
474  * VSTACK set since these are currently allocated on the stack.
475  */
476 
477 MKINIT void shprocvar(void);
478 
479 #ifdef mkinit
480 SHELLPROC {
481 	shprocvar();
482 }
483 #endif
484 
485 void
486 shprocvar(void)
487 {
488 	struct var **vpp;
489 	struct var *vp, **prev;
490 
491 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
492 		for (prev = vpp ; (vp = *prev) != NULL ; ) {
493 			if ((vp->flags & VEXPORT) == 0) {
494 				*prev = vp->next;
495 				if ((vp->flags & VTEXTFIXED) == 0)
496 					ckfree(vp->text);
497 				if ((vp->flags & VSTRFIXED) == 0)
498 					ckfree(vp);
499 			} else {
500 				if (vp->flags & VSTACK) {
501 					vp->text = savestr(vp->text);
502 					vp->flags &=~ VSTACK;
503 				}
504 				prev = &vp->next;
505 			}
506 		}
507 	}
508 	initvar();
509 }
510 
511 
512 static int
513 var_compare(const void *a, const void *b)
514 {
515 	const char *const *sa, *const *sb;
516 
517 	sa = a;
518 	sb = b;
519 	/*
520 	 * This compares two var=value strings which creates a different
521 	 * order from what you would probably expect.  POSIX is somewhat
522 	 * ambiguous on what should be sorted exactly.
523 	 */
524 	return strcoll(*sa, *sb);
525 }
526 
527 
528 /*
529  * Command to list all variables which are set.  Currently this command
530  * is invoked from the set command when the set command is called without
531  * any variables.
532  */
533 
534 int
535 showvarscmd(int argc __unused, char **argv __unused)
536 {
537 	struct var **vpp;
538 	struct var *vp;
539 	const char *s;
540 	const char **vars;
541 	int i, n;
542 
543 	/*
544 	 * POSIX requires us to sort the variables.
545 	 */
546 	n = 0;
547 	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
548 		for (vp = *vpp; vp; vp = vp->next) {
549 			if (!(vp->flags & VUNSET))
550 				n++;
551 		}
552 	}
553 
554 	INTON;
555 	vars = ckmalloc(n * sizeof(*vars));
556 	i = 0;
557 	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
558 		for (vp = *vpp; vp; vp = vp->next) {
559 			if (!(vp->flags & VUNSET))
560 				vars[i++] = vp->text;
561 		}
562 	}
563 
564 	qsort(vars, n, sizeof(*vars), var_compare);
565 	for (i = 0; i < n; i++) {
566 		for (s = vars[i]; *s != '='; s++)
567 			out1c(*s);
568 		out1c('=');
569 		out1qstr(s + 1);
570 		out1c('\n');
571 	}
572 	ckfree(vars);
573 	INTOFF;
574 
575 	return 0;
576 }
577 
578 
579 
580 /*
581  * The export and readonly commands.
582  */
583 
584 int
585 exportcmd(int argc, char **argv)
586 {
587 	struct var **vpp;
588 	struct var *vp;
589 	char *name;
590 	char *p;
591 	char *cmdname;
592 	int ch, values;
593 	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
594 
595 	cmdname = argv[0];
596 	optreset = optind = 1;
597 	opterr = 0;
598 	values = 0;
599 	while ((ch = getopt(argc, argv, "p")) != -1) {
600 		switch (ch) {
601 		case 'p':
602 			values = 1;
603 			break;
604 		case '?':
605 		default:
606 			error("unknown option: -%c", optopt);
607 		}
608 	}
609 	argc -= optind;
610 	argv += optind;
611 
612 	if (values && argc != 0)
613 		error("-p requires no arguments");
614 	if (argc != 0) {
615 		while ((name = *argv++) != NULL) {
616 			if ((p = strchr(name, '=')) != NULL) {
617 				p++;
618 			} else {
619 				vpp = hashvar(name);
620 				for (vp = *vpp ; vp ; vp = vp->next) {
621 					if (varequal(vp->text, name)) {
622 
623 						vp->flags |= flag;
624 						if ((vp->flags & VEXPORT) && localevar(vp->text)) {
625 							change_env(vp->text, 1);
626 							(void) setlocale(LC_ALL, "");
627 						}
628 						goto found;
629 					}
630 				}
631 			}
632 			setvar(name, p, flag);
633 found:;
634 		}
635 	} else {
636 		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
637 			for (vp = *vpp ; vp ; vp = vp->next) {
638 				if (vp->flags & flag) {
639 					if (values) {
640 						out1str(cmdname);
641 						out1c(' ');
642 					}
643 					for (p = vp->text ; *p != '=' ; p++)
644 						out1c(*p);
645 					if (values && !(vp->flags & VUNSET)) {
646 						out1c('=');
647 						out1qstr(p + 1);
648 					}
649 					out1c('\n');
650 				}
651 			}
652 		}
653 	}
654 	return 0;
655 }
656 
657 
658 /*
659  * The "local" command.
660  */
661 
662 int
663 localcmd(int argc __unused, char **argv __unused)
664 {
665 	char *name;
666 
667 	if (! in_function())
668 		error("Not in a function");
669 	while ((name = *argptr++) != NULL) {
670 		mklocal(name);
671 	}
672 	return 0;
673 }
674 
675 
676 /*
677  * Make a variable a local variable.  When a variable is made local, it's
678  * value and flags are saved in a localvar structure.  The saved values
679  * will be restored when the shell function returns.  We handle the name
680  * "-" as a special case.
681  */
682 
683 void
684 mklocal(char *name)
685 {
686 	struct localvar *lvp;
687 	struct var **vpp;
688 	struct var *vp;
689 
690 	INTOFF;
691 	lvp = ckmalloc(sizeof (struct localvar));
692 	if (name[0] == '-' && name[1] == '\0') {
693 		lvp->text = ckmalloc(sizeof optlist);
694 		memcpy(lvp->text, optlist, sizeof optlist);
695 		vp = NULL;
696 	} else {
697 		vpp = hashvar(name);
698 		for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next);
699 		if (vp == NULL) {
700 			if (strchr(name, '='))
701 				setvareq(savestr(name), VSTRFIXED);
702 			else
703 				setvar(name, NULL, VSTRFIXED);
704 			vp = *vpp;	/* the new variable */
705 			lvp->text = NULL;
706 			lvp->flags = VUNSET;
707 		} else {
708 			lvp->text = vp->text;
709 			lvp->flags = vp->flags;
710 			vp->flags |= VSTRFIXED|VTEXTFIXED;
711 			if (strchr(name, '='))
712 				setvareq(savestr(name), 0);
713 		}
714 	}
715 	lvp->vp = vp;
716 	lvp->next = localvars;
717 	localvars = lvp;
718 	INTON;
719 }
720 
721 
722 /*
723  * Called after a function returns.
724  */
725 
726 void
727 poplocalvars(void)
728 {
729 	struct localvar *lvp;
730 	struct var *vp;
731 
732 	while ((lvp = localvars) != NULL) {
733 		localvars = lvp->next;
734 		vp = lvp->vp;
735 		if (vp == NULL) {	/* $- saved */
736 			memcpy(optlist, lvp->text, sizeof optlist);
737 			ckfree(lvp->text);
738 		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
739 			(void)unsetvar(vp->text);
740 		} else {
741 			if ((vp->flags & VTEXTFIXED) == 0)
742 				ckfree(vp->text);
743 			vp->flags = lvp->flags;
744 			vp->text = lvp->text;
745 		}
746 		ckfree(lvp);
747 	}
748 }
749 
750 
751 int
752 setvarcmd(int argc, char **argv)
753 {
754 	if (argc <= 2)
755 		return unsetcmd(argc, argv);
756 	else if (argc == 3)
757 		setvar(argv[1], argv[2], 0);
758 	else
759 		error("List assignment not implemented");
760 	return 0;
761 }
762 
763 
764 /*
765  * The unset builtin command.  We unset the function before we unset the
766  * variable to allow a function to be unset when there is a readonly variable
767  * with the same name.
768  */
769 
770 int
771 unsetcmd(int argc __unused, char **argv __unused)
772 {
773 	char **ap;
774 	int i;
775 	int flg_func = 0;
776 	int flg_var = 0;
777 	int ret = 0;
778 
779 	while ((i = nextopt("vf")) != '\0') {
780 		if (i == 'f')
781 			flg_func = 1;
782 		else
783 			flg_var = 1;
784 	}
785 	if (flg_func == 0 && flg_var == 0)
786 		flg_var = 1;
787 
788 	for (ap = argptr; *ap ; ap++) {
789 		if (flg_func)
790 			ret |= unsetfunc(*ap);
791 		if (flg_var)
792 			ret |= unsetvar(*ap);
793 	}
794 	return ret;
795 }
796 
797 
798 /*
799  * Unset the specified variable.
800  */
801 
802 int
803 unsetvar(const char *s)
804 {
805 	struct var **vpp;
806 	struct var *vp;
807 
808 	vpp = hashvar(s);
809 	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
810 		if (varequal(vp->text, s)) {
811 			if (vp->flags & VREADONLY)
812 				return (1);
813 			INTOFF;
814 			if (*(strchr(vp->text, '=') + 1) != '\0')
815 				setvar(s, nullstr, 0);
816 			if ((vp->flags & VEXPORT) && localevar(vp->text)) {
817 				change_env(s, 0);
818 				setlocale(LC_ALL, "");
819 			}
820 			vp->flags &= ~VEXPORT;
821 			vp->flags |= VUNSET;
822 			if ((vp->flags & VSTRFIXED) == 0) {
823 				if ((vp->flags & VTEXTFIXED) == 0)
824 					ckfree(vp->text);
825 				*vpp = vp->next;
826 				ckfree(vp);
827 			}
828 			INTON;
829 			return (0);
830 		}
831 	}
832 
833 	return (0);
834 }
835 
836 
837 
838 /*
839  * Find the appropriate entry in the hash table from the name.
840  */
841 
842 STATIC struct var **
843 hashvar(const char *p)
844 {
845 	unsigned int hashval;
846 
847 	hashval = ((unsigned char) *p) << 4;
848 	while (*p && *p != '=')
849 		hashval += (unsigned char) *p++;
850 	return &vartab[hashval % VTABSIZE];
851 }
852 
853 
854 
855 /*
856  * Returns true if the two strings specify the same varable.  The first
857  * variable name is terminated by '='; the second may be terminated by
858  * either '=' or '\0'.
859  */
860 
861 STATIC int
862 varequal(const char *p, const char *q)
863 {
864 	while (*p == *q++) {
865 		if (*p++ == '=')
866 			return 1;
867 	}
868 	if (*p == '=' && *(q - 1) == '\0')
869 		return 1;
870 	return 0;
871 }
872