var.c revision 217847 
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
35static char sccsid[] = "@(#)var.c	8.3 (Berkeley) 5/4/95";
36#endif
37#endif /* not lint */
38#include <sys/cdefs.h>
39__FBSDID("$FreeBSD: head/bin/sh/var.c 217847 2011-01-25 20:56:18Z jilles $");
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
73struct varinit {
74	struct var *var;
75	int flags;
76	const char *text;
77	void (*func)(const char *);
78};
79
80
81#ifndef NO_HISTORY
82struct var vhistsize;
83struct var vterm;
84#endif
85struct var vifs;
86struct var vmail;
87struct var vmpath;
88struct var vpath;
89struct var vppid;
90struct var vps1;
91struct var vps2;
92struct var vps4;
93struct var vvers;
94static struct var voptind;
95
96static const struct varinit varinit[] = {
97#ifndef NO_HISTORY
98	{ &vhistsize,	VUNSET,				"HISTSIZE=",
99	  sethistsize },
100#endif
101	{ &vifs,	0,				"IFS= \t\n",
102	  NULL },
103	{ &vmail,	VUNSET,				"MAIL=",
104	  NULL },
105	{ &vmpath,	VUNSET,				"MAILPATH=",
106	  NULL },
107	{ &vpath,	0,				"PATH=" _PATH_DEFPATH,
108	  changepath },
109	{ &vppid,	VUNSET,				"PPID=",
110	  NULL },
111	/*
112	 * vps1 depends on uid
113	 */
114	{ &vps2,	0,				"PS2=> ",
115	  NULL },
116	{ &vps4,	0,				"PS4=+ ",
117	  NULL },
118#ifndef NO_HISTORY
119	{ &vterm,	VUNSET,				"TERM=",
120	  setterm },
121#endif
122	{ &voptind,	0,				"OPTIND=1",
123	  getoptsreset },
124	{ NULL,	0,				NULL,
125	  NULL }
126};
127
128static struct var *vartab[VTABSIZE];
129
130static const char *const locale_names[7] = {
131	"LC_COLLATE", "LC_CTYPE", "LC_MONETARY",
132	"LC_NUMERIC", "LC_TIME", "LC_MESSAGES", NULL
133};
134static const int locale_categories[7] = {
135	LC_COLLATE, LC_CTYPE, LC_MONETARY, LC_NUMERIC, LC_TIME, LC_MESSAGES, 0
136};
137
138static struct var **hashvar(const char *);
139static int varequal(const char *, const char *);
140static int localevar(const char *);
141
142/*
143 * Initialize the variable symbol tables and import the environment.
144 */
145
146#ifdef mkinit
147INCLUDE "var.h"
148MKINIT char **environ;
149INIT {
150	char **envp;
151
152	initvar();
153	for (envp = environ ; *envp ; envp++) {
154		if (strchr(*envp, '=')) {
155			setvareq(*envp, VEXPORT|VTEXTFIXED);
156		}
157	}
158}
159#endif
160
161
162/*
163 * This routine initializes the builtin variables.  It is called when the
164 * shell is initialized and again when a shell procedure is spawned.
165 */
166
167void
168initvar(void)
169{
170	char ppid[20];
171	const struct varinit *ip;
172	struct var *vp;
173	struct var **vpp;
174
175	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
176		if ((vp->flags & VEXPORT) == 0) {
177			vpp = hashvar(ip->text);
178			vp->next = *vpp;
179			*vpp = vp;
180			vp->text = __DECONST(char *, ip->text);
181			vp->flags = ip->flags | VSTRFIXED | VTEXTFIXED;
182			vp->func = ip->func;
183		}
184	}
185	/*
186	 * PS1 depends on uid
187	 */
188	if ((vps1.flags & VEXPORT) == 0) {
189		vpp = hashvar("PS1=");
190		vps1.next = *vpp;
191		*vpp = &vps1;
192		vps1.text = __DECONST(char *, geteuid() ? "PS1=$ " : "PS1=# ");
193		vps1.flags = VSTRFIXED|VTEXTFIXED;
194	}
195	if ((vppid.flags & VEXPORT) == 0) {
196		fmtstr(ppid, sizeof(ppid), "%d", (int)getppid());
197		setvarsafe("PPID", ppid, 0);
198	}
199}
200
201/*
202 * Safe version of setvar, returns 1 on success 0 on failure.
203 */
204
205int
206setvarsafe(const char *name, const char *val, int flags)
207{
208	struct jmploc jmploc;
209	struct jmploc *const savehandler = handler;
210	int err = 0;
211	int inton;
212
213	inton = is_int_on();
214	if (setjmp(jmploc.loc))
215		err = 1;
216	else {
217		handler = &jmploc;
218		setvar(name, val, flags);
219	}
220	handler = savehandler;
221	SETINTON(inton);
222	return err;
223}
224
225/*
226 * Set the value of a variable.  The flags argument is stored with the
227 * flags of the variable.  If val is NULL, the variable is unset.
228 */
229
230void
231setvar(const char *name, const char *val, int flags)
232{
233	const char *p;
234	int len;
235	int namelen;
236	char *nameeq;
237	int isbad;
238
239	isbad = 0;
240	p = name;
241	if (! is_name(*p))
242		isbad = 1;
243	p++;
244	for (;;) {
245		if (! is_in_name(*p)) {
246			if (*p == '\0' || *p == '=')
247				break;
248			isbad = 1;
249		}
250		p++;
251	}
252	namelen = p - name;
253	if (isbad)
254		error("%.*s: bad variable name", namelen, name);
255	len = namelen + 2;		/* 2 is space for '=' and '\0' */
256	if (val == NULL) {
257		flags |= VUNSET;
258	} else {
259		len += strlen(val);
260	}
261	nameeq = ckmalloc(len);
262	memcpy(nameeq, name, namelen);
263	nameeq[namelen] = '=';
264	if (val)
265		scopy(val, nameeq + namelen + 1);
266	else
267		nameeq[namelen + 1] = '\0';
268	setvareq(nameeq, flags);
269}
270
271static int
272localevar(const char *s)
273{
274	const char *const *ss;
275
276	if (*s != 'L')
277		return 0;
278	if (varequal(s + 1, "ANG"))
279		return 1;
280	if (strncmp(s + 1, "C_", 2) != 0)
281		return 0;
282	if (varequal(s + 3, "ALL"))
283		return 1;
284	for (ss = locale_names; *ss ; ss++)
285		if (varequal(s + 3, *ss + 3))
286			return 1;
287	return 0;
288}
289
290
291/*
292 * Sets/unsets an environment variable from a pointer that may actually be a
293 * pointer into environ where the string should not be manipulated.
294 */
295static void
296change_env(const char *s, int set)
297{
298	char *eqp;
299	char *ss;
300
301	ss = savestr(s);
302	if ((eqp = strchr(ss, '=')) != NULL)
303		*eqp = '\0';
304	if (set && eqp != NULL)
305		(void) setenv(ss, eqp + 1, 1);
306	else
307		(void) unsetenv(ss);
308	ckfree(ss);
309
310	return;
311}
312
313
314/*
315 * Same as setvar except that the variable and value are passed in
316 * the first argument as name=value.  Since the first argument will
317 * be actually stored in the table, it should not be a string that
318 * will go away.
319 */
320
321void
322setvareq(char *s, int flags)
323{
324	struct var *vp, **vpp;
325	int len;
326
327	if (aflag)
328		flags |= VEXPORT;
329	vpp = hashvar(s);
330	for (vp = *vpp ; vp ; vp = vp->next) {
331		if (varequal(s, vp->text)) {
332			if (vp->flags & VREADONLY) {
333				len = strchr(s, '=') - s;
334				error("%.*s: is read only", len, s);
335			}
336			if (flags & VNOSET)
337				return;
338			INTOFF;
339
340			if (vp->func && (flags & VNOFUNC) == 0)
341				(*vp->func)(strchr(s, '=') + 1);
342
343			if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
344				ckfree(vp->text);
345
346			vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
347			vp->flags |= flags;
348			vp->text = s;
349
350			/*
351			 * We could roll this to a function, to handle it as
352			 * a regular variable function callback, but why bother?
353			 *
354			 * Note: this assumes iflag is not set to 1 initially.
355			 * As part of init(), this is called before arguments
356			 * are looked at.
357			 */
358			if ((vp == &vmpath || (vp == &vmail && ! mpathset())) &&
359			    iflag == 1)
360				chkmail(1);
361			if ((vp->flags & VEXPORT) && localevar(s)) {
362				change_env(s, 1);
363				(void) setlocale(LC_ALL, "");
364			}
365			INTON;
366			return;
367		}
368	}
369	/* not found */
370	if (flags & VNOSET)
371		return;
372	vp = ckmalloc(sizeof (*vp));
373	vp->flags = flags;
374	vp->text = s;
375	vp->next = *vpp;
376	vp->func = NULL;
377	INTOFF;
378	*vpp = vp;
379	if ((vp->flags & VEXPORT) && localevar(s)) {
380		change_env(s, 1);
381		(void) setlocale(LC_ALL, "");
382	}
383	INTON;
384}
385
386
387
388/*
389 * Process a linked list of variable assignments.
390 */
391
392void
393listsetvar(struct strlist *list, int flags)
394{
395	struct strlist *lp;
396
397	INTOFF;
398	for (lp = list ; lp ; lp = lp->next) {
399		setvareq(savestr(lp->text), flags);
400	}
401	INTON;
402}
403
404
405
406/*
407 * Find the value of a variable.  Returns NULL if not set.
408 */
409
410char *
411lookupvar(const char *name)
412{
413	struct var *v;
414
415	for (v = *hashvar(name) ; v ; v = v->next) {
416		if (varequal(v->text, name)) {
417			if (v->flags & VUNSET)
418				return NULL;
419			return strchr(v->text, '=') + 1;
420		}
421	}
422	return NULL;
423}
424
425
426
427/*
428 * Search the environment of a builtin command.  If the second argument
429 * is nonzero, return the value of a variable even if it hasn't been
430 * exported.
431 */
432
433char *
434bltinlookup(const char *name, int doall)
435{
436	struct strlist *sp;
437	struct var *v;
438	char *result;
439
440	result = NULL;
441	for (sp = cmdenviron ; sp ; sp = sp->next) {
442		if (varequal(sp->text, name))
443			result = strchr(sp->text, '=') + 1;
444	}
445	if (result != NULL)
446		return result;
447	for (v = *hashvar(name) ; v ; v = v->next) {
448		if (varequal(v->text, name)) {
449			if ((v->flags & VUNSET)
450			 || (!doall && (v->flags & VEXPORT) == 0))
451				return NULL;
452			return strchr(v->text, '=') + 1;
453		}
454	}
455	return NULL;
456}
457
458
459/*
460 * Set up locale for a builtin (LANG/LC_* assignments).
461 */
462void
463bltinsetlocale(void)
464{
465	struct strlist *lp;
466	int act = 0;
467	char *loc, *locdef;
468	int i;
469
470	for (lp = cmdenviron ; lp ; lp = lp->next) {
471		if (localevar(lp->text)) {
472			act = 1;
473			break;
474		}
475	}
476	if (!act)
477		return;
478	loc = bltinlookup("LC_ALL", 0);
479	INTOFF;
480	if (loc != NULL) {
481		setlocale(LC_ALL, loc);
482		INTON;
483		return;
484	}
485	locdef = bltinlookup("LANG", 0);
486	for (i = 0; locale_names[i] != NULL; i++) {
487		loc = bltinlookup(locale_names[i], 0);
488		if (loc == NULL)
489			loc = locdef;
490		if (loc != NULL)
491			setlocale(locale_categories[i], loc);
492	}
493	INTON;
494}
495
496/*
497 * Undo the effect of bltinlocaleset().
498 */
499void
500bltinunsetlocale(void)
501{
502	struct strlist *lp;
503
504	INTOFF;
505	for (lp = cmdenviron ; lp ; lp = lp->next) {
506		if (localevar(lp->text)) {
507			setlocale(LC_ALL, "");
508			return;
509		}
510	}
511	INTON;
512}
513
514
515/*
516 * Generate a list of exported variables.  This routine is used to construct
517 * the third argument to execve when executing a program.
518 */
519
520char **
521environment(void)
522{
523	int nenv;
524	struct var **vpp;
525	struct var *vp;
526	char **env, **ep;
527
528	nenv = 0;
529	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
530		for (vp = *vpp ; vp ; vp = vp->next)
531			if (vp->flags & VEXPORT)
532				nenv++;
533	}
534	ep = env = stalloc((nenv + 1) * sizeof *env);
535	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
536		for (vp = *vpp ; vp ; vp = vp->next)
537			if (vp->flags & VEXPORT)
538				*ep++ = vp->text;
539	}
540	*ep = NULL;
541	return env;
542}
543
544
545/*
546 * Called when a shell procedure is invoked to clear out nonexported
547 * variables.  It is also necessary to reallocate variables of with
548 * VSTACK set since these are currently allocated on the stack.
549 */
550
551MKINIT void shprocvar(void);
552
553#ifdef mkinit
554SHELLPROC {
555	shprocvar();
556}
557#endif
558
559void
560shprocvar(void)
561{
562	struct var **vpp;
563	struct var *vp, **prev;
564
565	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
566		for (prev = vpp ; (vp = *prev) != NULL ; ) {
567			if ((vp->flags & VEXPORT) == 0) {
568				*prev = vp->next;
569				if ((vp->flags & VTEXTFIXED) == 0)
570					ckfree(vp->text);
571				if ((vp->flags & VSTRFIXED) == 0)
572					ckfree(vp);
573			} else {
574				if (vp->flags & VSTACK) {
575					vp->text = savestr(vp->text);
576					vp->flags &=~ VSTACK;
577				}
578				prev = &vp->next;
579			}
580		}
581	}
582	initvar();
583}
584
585
586static int
587var_compare(const void *a, const void *b)
588{
589	const char *const *sa, *const *sb;
590
591	sa = a;
592	sb = b;
593	/*
594	 * This compares two var=value strings which creates a different
595	 * order from what you would probably expect.  POSIX is somewhat
596	 * ambiguous on what should be sorted exactly.
597	 */
598	return strcoll(*sa, *sb);
599}
600
601
602/*
603 * Command to list all variables which are set.  This is invoked from the
604 * set command when it is called without any options or operands.
605 */
606
607int
608showvarscmd(int argc __unused, char **argv __unused)
609{
610	struct var **vpp;
611	struct var *vp;
612	const char *s;
613	const char **vars;
614	int i, n;
615
616	/*
617	 * POSIX requires us to sort the variables.
618	 */
619	n = 0;
620	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
621		for (vp = *vpp; vp; vp = vp->next) {
622			if (!(vp->flags & VUNSET))
623				n++;
624		}
625	}
626
627	INTON;
628	vars = ckmalloc(n * sizeof(*vars));
629	i = 0;
630	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
631		for (vp = *vpp; vp; vp = vp->next) {
632			if (!(vp->flags & VUNSET))
633				vars[i++] = vp->text;
634		}
635	}
636
637	qsort(vars, n, sizeof(*vars), var_compare);
638	for (i = 0; i < n; i++) {
639		s = strchr(vars[i], '=');
640		s++;
641		outbin(vars[i], s - vars[i], out1);
642		out1qstr(s);
643		out1c('\n');
644	}
645	ckfree(vars);
646	INTOFF;
647
648	return 0;
649}
650
651
652
653/*
654 * The export and readonly commands.
655 */
656
657int
658exportcmd(int argc, char **argv)
659{
660	struct var **vpp;
661	struct var *vp;
662	char *name;
663	char *p;
664	char *cmdname;
665	int ch, values;
666	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
667
668	cmdname = argv[0];
669	optreset = optind = 1;
670	opterr = 0;
671	values = 0;
672	while ((ch = getopt(argc, argv, "p")) != -1) {
673		switch (ch) {
674		case 'p':
675			values = 1;
676			break;
677		case '?':
678		default:
679			error("unknown option: -%c", optopt);
680		}
681	}
682	argc -= optind;
683	argv += optind;
684
685	if (values && argc != 0)
686		error("-p requires no arguments");
687	if (argc != 0) {
688		while ((name = *argv++) != NULL) {
689			if ((p = strchr(name, '=')) != NULL) {
690				p++;
691			} else {
692				vpp = hashvar(name);
693				for (vp = *vpp ; vp ; vp = vp->next) {
694					if (varequal(vp->text, name)) {
695
696						vp->flags |= flag;
697						if ((vp->flags & VEXPORT) && localevar(vp->text)) {
698							change_env(vp->text, 1);
699							(void) setlocale(LC_ALL, "");
700						}
701						goto found;
702					}
703				}
704			}
705			setvar(name, p, flag);
706found:;
707		}
708	} else {
709		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
710			for (vp = *vpp ; vp ; vp = vp->next) {
711				if (vp->flags & flag) {
712					if (values) {
713						out1str(cmdname);
714						out1c(' ');
715					}
716					p = strchr(vp->text, '=');
717					if (values && !(vp->flags & VUNSET)) {
718						p++;
719						outbin(vp->text, p - vp->text,
720						    out1);
721						out1qstr(p);
722					} else
723						outbin(vp->text, p - vp->text,
724						    out1);
725					out1c('\n');
726				}
727			}
728		}
729	}
730	return 0;
731}
732
733
734/*
735 * The "local" command.
736 */
737
738int
739localcmd(int argc __unused, char **argv __unused)
740{
741	char *name;
742
743	if (! in_function())
744		error("Not in a function");
745	while ((name = *argptr++) != NULL) {
746		mklocal(name);
747	}
748	return 0;
749}
750
751
752/*
753 * Make a variable a local variable.  When a variable is made local, it's
754 * value and flags are saved in a localvar structure.  The saved values
755 * will be restored when the shell function returns.  We handle the name
756 * "-" as a special case.
757 */
758
759void
760mklocal(char *name)
761{
762	struct localvar *lvp;
763	struct var **vpp;
764	struct var *vp;
765
766	INTOFF;
767	lvp = ckmalloc(sizeof (struct localvar));
768	if (name[0] == '-' && name[1] == '\0') {
769		lvp->text = ckmalloc(sizeof optlist);
770		memcpy(lvp->text, optlist, sizeof optlist);
771		vp = NULL;
772	} else {
773		vpp = hashvar(name);
774		for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next);
775		if (vp == NULL) {
776			if (strchr(name, '='))
777				setvareq(savestr(name), VSTRFIXED);
778			else
779				setvar(name, NULL, VSTRFIXED);
780			vp = *vpp;	/* the new variable */
781			lvp->text = NULL;
782			lvp->flags = VUNSET;
783		} else {
784			lvp->text = vp->text;
785			lvp->flags = vp->flags;
786			vp->flags |= VSTRFIXED|VTEXTFIXED;
787			if (strchr(name, '='))
788				setvareq(savestr(name), 0);
789		}
790	}
791	lvp->vp = vp;
792	lvp->next = localvars;
793	localvars = lvp;
794	INTON;
795}
796
797
798/*
799 * Called after a function returns.
800 */
801
802void
803poplocalvars(void)
804{
805	struct localvar *lvp;
806	struct var *vp;
807
808	while ((lvp = localvars) != NULL) {
809		localvars = lvp->next;
810		vp = lvp->vp;
811		if (vp == NULL) {	/* $- saved */
812			memcpy(optlist, lvp->text, sizeof optlist);
813			ckfree(lvp->text);
814			optschanged();
815		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
816			(void)unsetvar(vp->text);
817		} else {
818			if ((vp->flags & VTEXTFIXED) == 0)
819				ckfree(vp->text);
820			vp->flags = lvp->flags;
821			vp->text = lvp->text;
822		}
823		ckfree(lvp);
824	}
825}
826
827
828int
829setvarcmd(int argc, char **argv)
830{
831	if (argc <= 2)
832		return unsetcmd(argc, argv);
833	else if (argc == 3)
834		setvar(argv[1], argv[2], 0);
835	else
836		error("too many arguments");
837	return 0;
838}
839
840
841/*
842 * The unset builtin command.
843 */
844
845int
846unsetcmd(int argc __unused, char **argv __unused)
847{
848	char **ap;
849	int i;
850	int flg_func = 0;
851	int flg_var = 0;
852	int ret = 0;
853
854	while ((i = nextopt("vf")) != '\0') {
855		if (i == 'f')
856			flg_func = 1;
857		else
858			flg_var = 1;
859	}
860	if (flg_func == 0 && flg_var == 0)
861		flg_var = 1;
862
863	for (ap = argptr; *ap ; ap++) {
864		if (flg_func)
865			ret |= unsetfunc(*ap);
866		if (flg_var)
867			ret |= unsetvar(*ap);
868	}
869	return ret;
870}
871
872
873/*
874 * Unset the specified variable.
875 */
876
877int
878unsetvar(const char *s)
879{
880	struct var **vpp;
881	struct var *vp;
882
883	vpp = hashvar(s);
884	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
885		if (varequal(vp->text, s)) {
886			if (vp->flags & VREADONLY)
887				return (1);
888			INTOFF;
889			if (*(strchr(vp->text, '=') + 1) != '\0')
890				setvar(s, nullstr, 0);
891			if ((vp->flags & VEXPORT) && localevar(vp->text)) {
892				change_env(s, 0);
893				setlocale(LC_ALL, "");
894			}
895			vp->flags &= ~VEXPORT;
896			vp->flags |= VUNSET;
897			if ((vp->flags & VSTRFIXED) == 0) {
898				if ((vp->flags & VTEXTFIXED) == 0)
899					ckfree(vp->text);
900				*vpp = vp->next;
901				ckfree(vp);
902			}
903			INTON;
904			return (0);
905		}
906	}
907
908	return (0);
909}
910
911
912
913/*
914 * Find the appropriate entry in the hash table from the name.
915 */
916
917static struct var **
918hashvar(const char *p)
919{
920	unsigned int hashval;
921
922	hashval = ((unsigned char) *p) << 4;
923	while (*p && *p != '=')
924		hashval += (unsigned char) *p++;
925	return &vartab[hashval % VTABSIZE];
926}
927
928
929
930/*
931 * Returns true if the two strings specify the same varable.  The first
932 * variable name is terminated by '='; the second may be terminated by
933 * either '=' or '\0'.
934 */
935
936static int
937varequal(const char *p, const char *q)
938{
939	while (*p == *q++) {
940		if (*p++ == '=')
941			return 1;
942	}
943	if (*p == '=' && *(q - 1) == '\0')
944		return 1;
945	return 0;
946}
947