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source: trunk/src/kash/var.c@ 1505

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1	/* $NetBSD: var.c,v 1.36 2004/10/06 10:23:43 enami Exp $ */
2
3	/*-
4	* Copyright (c) 1991, 1993
5	* The Regents of the University of California. All rights reserved.
6	*
7	* This code is derived from software contributed to Berkeley by
8	* Kenneth Almquist.
9	*
10	* Redistribution and use in source and binary forms, with or without
11	* modification, are permitted provided that the following conditions
12	* are met:
13	* 1. Redistributions of source code must retain the above copyright
14	* notice, this list of conditions and the following disclaimer.
15	* 2. Redistributions in binary form must reproduce the above copyright
16	* notice, this list of conditions and the following disclaimer in the
17	* documentation and/or other materials provided with the distribution.
18	* 3. Neither the name of the University nor the names of its contributors
19	* may be used to endorse or promote products derived from this software
20	* without specific prior written permission.
21	*
22	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32	* SUCH DAMAGE.
33	*/
34
35	#if 0
36	#ifndef lint
37	static char sccsid[] = "@(#)var.c 8.3 (Berkeley) 5/4/95";
38	#else
39	__RCSID("$NetBSD: var.c,v 1.36 2004/10/06 10:23:43 enami Exp $");
40	#endif /* not lint */
41	#endif
42
43	#include <stddef.h>
44	#include <stdlib.h>
45	#include <string.h>
46
47	#ifdef PC_OS2_LIBPATHS
48	#define INCL_BASE
49	#include <os2.h>
50
51	#ifndef LIBPATHSTRICT
52	#define LIBPATHSTRICT 3
53	#endif
54
55	extern APIRET
56	#ifdef APIENTRY
57	APIENTRY
58	#endif
59	DosQueryHeaderInfo(HMODULE hmod, ULONG ulIndex, PVOID pvBuffer, ULONG cbBuffer, ULONG ulSubFunction);
60	#define QHINF_EXEINFO 1 /* NE exeinfo. */
61	#define QHINF_READRSRCTBL 2 /* Reads from the resource table. */
62	#define QHINF_READFILE 3 /* Reads from the executable file. */
63	#define QHINF_LIBPATHLENGTH 4 /* Gets the libpath length. */
64	#define QHINF_LIBPATH 5 /* Gets the entire libpath. */
65	#define QHINF_FIXENTRY 6 /* NE only */
66	#define QHINF_STE 7 /* NE only */
67	#define QHINF_MAPSEL 8 /* NE only */
68
69	#endif
70
71
72	/*
73	* Shell variables.
74	*/
75
76	#include "shell.h"
77	#include "output.h"
78	#include "expand.h"
79	#include "nodes.h" /* for other headers */
80	#include "eval.h" /* defines cmdenviron */
81	#include "exec.h"
82	#include "syntax.h"
83	#include "options.h"
84	#include "mail.h"
85	#include "var.h"
86	#include "memalloc.h"
87	#include "error.h"
88	#include "mystring.h"
89	#include "parser.h"
90	#include "show.h"
91	#ifndef SMALL
92	# include "myhistedit.h"
93	#endif
94	#include "shinstance.h"
95
96	//#ifdef SMALL
97	//#define VTABSIZE 39
98	//#else
99	//#define VTABSIZE 517
100	//#endif
101
102
103	struct varinit {
104	unsigned var_off;
105	int flags;
106	const char *text;
107	void (func)(shinstance , const char *);
108	};
109
110
111	//#if ATTY
112	//struct var vatty;
113	//#endif
114	//#ifndef SMALL
115	//struct var vhistsize;
116	//struct var vterm;
117	//#endif
118	//struct var vifs;
119	//struct var vmail;
120	//struct var vmpath;
121	//struct var vpath;
122	//#ifdef _MSC_VER
123	//struct var vpath2;
124	//#endif
125	//struct var vps1;
126	//struct var vps2;
127	//struct var vps4;
128	//struct var vvers; - unused
129	//struct var voptind;
130
131	#ifdef PC_OS2_LIBPATHS
132	//static struct var libpath_vars[4];
133	static const char * const libpath_envs[4] = {"LIBPATH=", "BEGINLIBPATH=", "ENDLIBPATH=", "LIBPATHSTRICT="};
134	#endif
135
136	const struct varinit varinit[] = {
137	#if ATTY
138	{ offsetof(shinstance, vatty), VSTRFIXED\|VTEXTFIXED\|VUNSET, "ATTY=",
139	NULL },
140	#endif
141	#ifndef SMALL
142	{ offsetof(shinstance, vhistsize), VSTRFIXED\|VTEXTFIXED\|VUNSET, "HISTSIZE=",
143	sethistsize },
144	#endif
145	{ offsetof(shinstance, vifs), VSTRFIXED\|VTEXTFIXED, "IFS= \t\n",
146	NULL },
147	{ offsetof(shinstance, vmail), VSTRFIXED\|VTEXTFIXED\|VUNSET, "MAIL=",
148	NULL },
149	{ offsetof(shinstance, vmpath), VSTRFIXED\|VTEXTFIXED\|VUNSET, "MAILPATH=",
150	NULL },
151	{ offsetof(shinstance, vpath), VSTRFIXED\|VTEXTFIXED, "PATH=" _PATH_DEFPATH,
152	changepath },
153	#ifdef _MSC_VER
154	{ offsetof(shinstance, vpath2), VSTRFIXED\|VTEXTFIXED, "Path=",
155	changepath },
156	#endif
157	/*
158	* vps1 depends on uid
159	*/
160	{ offsetof(shinstance, vps2), VSTRFIXED\|VTEXTFIXED, "PS2=> ",
161	NULL },
162	{ offsetof(shinstance, vps4), VSTRFIXED\|VTEXTFIXED, "PS4=+ ",
163	NULL },
164	#ifndef SMALL
165	{ offsetof(shinstance, vterm), VSTRFIXED\|VTEXTFIXED\|VUNSET, "TERM=",
166	setterm },
167	#endif
168	{ offsetof(shinstance, voptind), VSTRFIXED\|VTEXTFIXED\|VNOFUNC, "OPTIND=1",
169	getoptsreset },
170	{ 0, 0, NULL,
171	NULL }
172	};
173
174	//struct var *vartab[VTABSIZE];
175
176	STATIC int strequal(const char , const char );
177	STATIC struct var find_var(shinstance , const char , struct var *, int );
178
179	/*
180	* Initialize the varable symbol tables and import the environment
181	*/
182
183	#ifdef mkinit
184	INCLUDE "var.h"
185
186	INIT {
187	char **envp;
188
189	initvar(psh);
190	for (envp = sh_environ(psh) ; *envp ; envp++) {
191	if (strchr(*envp, '=')) {
192	setvareq(psh, *envp, VEXPORT\|VTEXTFIXED);
193	}
194	}
195	}
196	#endif
197
198
199	/*
200	* This routine initializes the builtin variables. It is called when the
201	* shell is initialized and again when a shell procedure is spawned.
202	*/
203
204	void
205	initvar(shinstance *psh)
206	{
207	const struct varinit *ip;
208	struct var *vp;
209	struct var **vpp;
210	#ifdef PC_OS2_LIBPATHS
211	char *psz = ckmalloc(2048);
212	int rc;
213	int i;
214
215	for (i = 0; i < 4; i++)
216	{
217	psh->libpath_vars[i].flags = VSTRFIXED \| VOS2LIBPATH;
218	psh->libpath_vars[i].func = NULL;
219
220	if (i > 0)
221	{
222	psz[0] = psz[1] = psz[2] = psz[3] = '\0';
223	rc = DosQueryExtLIBPATH(psz, i);
224	}
225	else
226	{
227	rc = DosQueryHeaderInfo(NULLHANDLE, 0, psz, 2048, QHINF_LIBPATH);
228	psh->libpath_vars[i].flags \|= VREADONLY;
229	}
230	if (!rc && *psz)
231	{
232	int cch1 = strlen(libpath_envs[i]);
233	int cch2 = strlen(psz) + 1;
234	psh->libpath_vars[i].text = ckmalloc(cch1 + cch2);
235	memcpy(psh->libpath_vars[i].text, libpath_envs[i], cch1);
236	memcpy(psh->libpath_vars[i].text + cch1, psz, cch2);
237	}
238	else
239	{
240	psh->libpath_vars[i].flags \|= VUNSET \| VTEXTFIXED;
241	psh->libpath_vars[i].text = (char*)libpath_envs[i];
242	}
243	if (find_var(psh, psh->libpath_vars[i].text, &vpp, &psh->libpath_vars[i].name_len) != NULL)
244	continue;
245	psh->libpath_vars[i].next = *vpp;
246	*vpp = &psh->libpath_vars[i];
247	}
248	free(psz);
249	#endif
250
251	for (ip = varinit; ip->text; ip++) {
252	vp = (struct var )((char )psh + ip->var_off);
253	if (find_var(psh, ip->text, &vpp, &vp->name_len) != NULL)
254	continue;
255	vp->next = *vpp;
256	*vpp = vp;
257	vp->text = strdup(ip->text);
258	vp->flags = ip->flags;
259	vp->func = ip->func;
260	}
261	/*
262	* PS1 depends on uid
263	*/
264	if (find_var(psh, "PS1", &vpp, &psh->vps1.name_len) == NULL) {
265	psh->vps1.next = *vpp;
266	*vpp = &psh->vps1;
267	psh->vps1.text = strdup(sh_geteuid(psh) ? "PS1=$ " : "PS1=# ");
268	psh->vps1.flags = VSTRFIXED\|VTEXTFIXED;
269	}
270	}
271
272	/*
273	* Safe version of setvar, returns 1 on success 0 on failure.
274	*/
275
276	int
277	setvarsafe(shinstance psh, const char name, const char *val, int flags)
278	{
279	struct jmploc jmploc;
280	struct jmploc *volatile savehandler = psh->handler;
281	int err = 0;
282	#ifdef __GNUC__
283	(void) &err;
284	#endif
285
286	if (setjmp(jmploc.loc))
287	err = 1;
288	else {
289	psh->handler = &jmploc;
290	setvar(psh, name, val, flags);
291	}
292	psh->handler = savehandler;
293	return err;
294	}
295
296	/*
297	* Set the value of a variable. The flags argument is ored with the
298	* flags of the variable. If val is NULL, the variable is unset.
299	*/
300
301	void
302	setvar(shinstance psh, const char name, const char *val, int flags)
303	{
304	const char *p;
305	const char *q;
306	char *d;
307	size_t len;
308	int namelen;
309	char *nameeq;
310	int isbad;
311
312	isbad = 0;
313	p = name;
314	if (! is_name(*p))
315	isbad = 1;
316	p++;
317	for (;;) {
318	if (! is_in_name(*p)) {
319	if (p == '\0' \|\| p == '=')
320	break;
321	isbad = 1;
322	}
323	p++;
324	}
325	namelen = (int)(p - name);
326	if (isbad)
327	error(psh, "%.*s: bad variable name", namelen, name);
328	len = namelen + 2; /* 2 is space for '=' and '\0' */
329	if (val == NULL) {
330	flags \|= VUNSET;
331	} else {
332	len += strlen(val);
333	}
334	d = nameeq = ckmalloc(len);
335	q = name;
336	while (--namelen >= 0)
337	d++ = q++;
338	*d++ = '=';
339	*d = '\0';
340	if (val)
341	scopy(val, d);
342	setvareq(psh, nameeq, flags);
343	}
344
345
346
347	/*
348	* Same as setvar except that the variable and value are passed in
349	* the first argument as name=value. Since the first argument will
350	* be actually stored in the table, it should not be a string that
351	* will go away.
352	*/
353
354	void
355	setvareq(shinstance psh, char s, int flags)
356	{
357	struct var vp, *vpp;
358	int nlen;
359
360	if (aflag(psh))
361	flags \|= VEXPORT;
362	vp = find_var(psh, s, &vpp, &nlen);
363	if (vp != NULL) {
364	if (vp->flags & VREADONLY)
365	error(psh, "%.*s: is read only", vp->name_len, s);
366	if (flags & VNOSET)
367	return;
368	INTOFF;
369
370	if (vp->func && (flags & VNOFUNC) == 0)
371	(*vp->func)(psh, s + vp->name_len + 1);
372
373	if ((vp->flags & (VTEXTFIXED\|VSTACK)) == 0)
374	ckfree(vp->text);
375
376	vp->flags &= ~(VTEXTFIXED\|VSTACK\|VUNSET);
377	vp->flags \|= flags & ~VNOFUNC;
378	vp->text = s;
379	#ifdef PC_OS2_LIBPATHS
380	if ((vp->flags & VOS2LIBPATH) && (vp->flags & VEXPORT))
381	vp->flags &= ~VEXPORT;
382	#endif
383
384	/*
385	* We could roll this to a function, to handle it as
386	* a regular variable function callback, but why bother?
387	*/
388	if (vp == &psh->vmpath \|\| (vp == &psh->vmail && ! mpathset(psh)))
389	chkmail(psh, 1);
390	INTON;
391	return;
392	}
393	/* not found */
394	if (flags & VNOSET)
395	return;
396	vp = ckmalloc(sizeof (*vp));
397	vp->flags = flags & ~VNOFUNC;
398	vp->text = s;
399	vp->name_len = nlen;
400	vp->next = *vpp;
401	vp->func = NULL;
402	*vpp = vp;
403	}
404
405
406
407	/*
408	* Process a linked list of variable assignments.
409	*/
410
411	void
412	listsetvar(shinstance psh, struct strlist list, int flags)
413	{
414	struct strlist *lp;
415
416	INTOFF;
417	for (lp = list ; lp ; lp = lp->next) {
418	setvareq(psh, savestr(lp->text), flags);
419	}
420	INTON;
421	}
422
423	void
424	listmklocal(shinstance psh, struct strlist list, int flags)
425	{
426	struct strlist *lp;
427
428	for (lp = list ; lp ; lp = lp->next)
429	mklocal(psh, lp->text, flags);
430	}
431
432
433	/*
434	* Find the value of a variable. Returns NULL if not set.
435	*/
436
437	char *
438	lookupvar(shinstance psh, const char name)
439	{
440	struct var *v;
441
442	v = find_var(psh, name, NULL, NULL);
443	if (v == NULL \|\| v->flags & VUNSET)
444	return NULL;
445	return v->text + v->name_len + 1;
446	}
447
448
449
450	/*
451	* Search the environment of a builtin command. If the second argument
452	* is nonzero, return the value of a variable even if it hasn't been
453	* exported.
454	*/
455
456	char *
457	bltinlookup(shinstance psh, const char name, int doall)
458	{
459	struct strlist *sp;
460	struct var *v;
461
462	for (sp = psh->cmdenviron ; sp ; sp = sp->next) {
463	if (strequal(sp->text, name))
464	return strchr(sp->text, '=') + 1;
465	}
466
467	v = find_var(psh, name, NULL, NULL);
468
469	if (v == NULL \|\| v->flags & VUNSET \|\| (!doall && !(v->flags & VEXPORT)))
470	return NULL;
471	return v->text + v->name_len + 1;
472	}
473
474
475
476	/*
477	* Generate a list of exported variables. This routine is used to construct
478	* the third argument to execve when executing a program.
479	*/
480
481	char **
482	environment(shinstance *psh)
483	{
484	int nenv;
485	struct var **vpp;
486	struct var *vp;
487	char **env;
488	char **ep;
489
490	nenv = 0;
491	for (vpp = psh->vartab ; vpp < psh->vartab + VTABSIZE ; vpp++) {
492	for (vp = *vpp ; vp ; vp = vp->next)
493	if (vp->flags & VEXPORT)
494	nenv++;
495	}
496	ep = env = stalloc(psh, (nenv + 1) * sizeof *env);
497	for (vpp = psh->vartab ; vpp < psh->vartab + VTABSIZE ; vpp++) {
498	for (vp = *vpp ; vp ; vp = vp->next)
499	if (vp->flags & VEXPORT)
500	*ep++ = vp->text;
501	}
502	*ep = NULL;
503
504	#ifdef PC_OS2_LIBPATHS
505	/*
506	* Set the libpaths now as this is exec() time.
507	*/
508	for (nenv = 0; nenv < 3; nenv++)
509	DosSetExtLIBPATH(strchr(psh->libpath_vars[nenv].text, '=') + 1, nenv);
510	#endif
511
512	return env;
513	}
514
515
516	/*
517	* Called when a shell procedure is invoked to clear out nonexported
518	* variables. It is also necessary to reallocate variables of with
519	* VSTACK set since these are currently allocated on the stack.
520	*/
521
522	#ifdef mkinit
523	void shprocvar(shinstance *psh);
524
525	SHELLPROC {
526	shprocvar(psh);
527	}
528	#endif
529
530	void
531	shprocvar(shinstance *psh)
532	{
533	struct var **vpp;
534	struct var vp, *prev;
535
536	for (vpp = psh->vartab ; vpp < psh->vartab + VTABSIZE ; vpp++) {
537	for (prev = vpp ; (vp = *prev) != NULL ; ) {
538	if ((vp->flags & VEXPORT) == 0) {
539	*prev = vp->next;
540	if ((vp->flags & VTEXTFIXED) == 0)
541	ckfree(vp->text);
542	if ((vp->flags & VSTRFIXED) == 0)
543	ckfree(vp);
544	} else {
545	if (vp->flags & VSTACK) {
546	vp->text = savestr(vp->text);
547	vp->flags &=~ VSTACK;
548	}
549	prev = &vp->next;
550	}
551	}
552	}
553	initvar(psh);
554	}
555
556
557
558	/*
559	* Command to list all variables which are set. Currently this command
560	* is invoked from the set command when the set command is called without
561	* any variables.
562	*/
563
564	void
565	print_quoted(shinstance psh, const char p)
566	{
567	const char *q;
568
569	if (strcspn(p, "\|&;<>()$`\\\"' \t\n*?[]#~=%") == strlen(p)) {
570	out1fmt(psh, "%s", p);
571	return;
572	}
573	while (*p) {
574	if (*p == '\'') {
575	out1fmt(psh, "\\'");
576	p++;
577	continue;
578	}
579	q = strchr(p, '\'');
580	if (!q) {
581	out1fmt(psh, "'%s'", p );
582	return;
583	}
584	out1fmt(psh, "'%.*s'", (int)(q - p), p );
585	p = q;
586	}
587	}
588
589	static int
590	sort_var(const void v_v1, const void v_v2)
591	{
592	const struct var * const *v1 = v_v1;
593	const struct var * const *v2 = v_v2;
594
595	/* XXX Will anyone notice we include the '=' of the shorter name? */
596	return strcoll((v1)->text, (v2)->text);
597	}
598
599	/*
600	* POSIX requires that 'set' (but not export or readonly) output the
601	* variables in lexicographic order - by the locale's collating order (sigh).
602	* Maybe we could keep them in an ordered balanced binary tree
603	* instead of hashed lists.
604	* For now just roll 'em through qsort for printing...
605	*/
606
607	int
608	showvars(shinstance psh, const char name, int flag, int show_value)
609	{
610	struct var **vpp;
611	struct var *vp;
612	const char *p;
613
614	static struct var *list; / static in case we are interrupted */
615	static int list_len;
616	int count = 0;
617
618	if (!list) {
619	list_len = 32;
620	list = ckmalloc(list_len * sizeof(*list));
621	}
622
623	for (vpp = psh->vartab ; vpp < psh->vartab + VTABSIZE ; vpp++) {
624	for (vp = *vpp ; vp ; vp = vp->next) {
625	if (flag && !(vp->flags & flag))
626	continue;
627	if (vp->flags & VUNSET && !(show_value & 2))
628	continue;
629	if (count >= list_len) {
630	list = ckrealloc(list,
631	(list_len << 1) * sizeof(*list));
632	list_len <<= 1;
633	}
634	list[count++] = vp;
635	}
636	}
637
638	qsort(list, count, sizeof(*list), sort_var);
639
640	for (vpp = list; count--; vpp++) {
641	vp = *vpp;
642	if (name)
643	out1fmt(psh, "%s ", name);
644	for (p = vp->text ; *p != '=' ; p++)
645	out1c(psh, *p);
646	if (!(vp->flags & VUNSET) && show_value) {
647	out1fmt(psh, "=");
648	print_quoted(psh, ++p);
649	}
650	out1c(psh, '\n');
651	}
652	return 0;
653	}
654
655
656
657	/*
658	* The export and readonly commands.
659	*/
660
661	int
662	exportcmd(shinstance psh, int argc, char *argv)
663	{
664	struct var *vp;
665	char *name;
666	const char *p;
667	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
668	int pflag;
669
670	pflag = nextopt(psh, "p") == 'p' ? 3 : 0;
671	if (argc <= 1 \|\| pflag) {
672	showvars(psh, pflag ? argv[0] : 0, flag, pflag );
673	return 0;
674	}
675
676	while ((name = *psh->argptr++) != NULL) {
677	if ((p = strchr(name, '=')) != NULL) {
678	p++;
679	} else {
680	vp = find_var(psh, name, NULL, NULL);
681	if (vp != NULL) {
682	vp->flags \|= flag;
683	continue;
684	}
685	}
686	setvar(psh, name, p, flag);
687	}
688	return 0;
689	}
690
691
692	/*
693	* The "local" command.
694	*/
695
696	int
697	localcmd(shinstance psh, int argc, char *argv)
698	{
699	char *name;
700
701	if (! in_function(psh))
702	error(psh, "Not in a function");
703	while ((name = *psh->argptr++) != NULL) {
704	mklocal(psh, name, 0);
705	}
706	return 0;
707	}
708
709
710	/*
711	* Make a variable a local variable. When a variable is made local, it's
712	* value and flags are saved in a localvar structure. The saved values
713	* will be restored when the shell function returns. We handle the name
714	* "-" as a special case.
715	*/
716
717	void
718	mklocal(shinstance psh, const char name, int flags)
719	{
720	struct localvar *lvp;
721	struct var **vpp;
722	struct var *vp;
723
724	INTOFF;
725	lvp = ckmalloc(sizeof (struct localvar));
726	if (name[0] == '-' && name[1] == '\0') {
727	char *p;
728	p = ckmalloc(sizeof_optlist);
729	lvp->text = memcpy(p, psh->optlist, sizeof_optlist);
730	vp = NULL;
731	} else {
732	vp = find_var(psh, name, &vpp, NULL);
733	if (vp == NULL) {
734	if (strchr(name, '='))
735	setvareq(psh, savestr(name), VSTRFIXED\|flags);
736	else
737	setvar(psh, name, NULL, VSTRFIXED\|flags);
738	vp = vpp; / the new variable */
739	lvp->text = NULL;
740	lvp->flags = VUNSET;
741	} else {
742	lvp->text = vp->text;
743	lvp->flags = vp->flags;
744	vp->flags \|= VSTRFIXED\|VTEXTFIXED;
745	if (name[vp->name_len] == '=')
746	setvareq(psh, savestr(name), flags);
747	}
748	}
749	lvp->vp = vp;
750	lvp->next = psh->localvars;
751	psh->localvars = lvp;
752	INTON;
753	}
754
755
756	/*
757	* Called after a function returns.
758	*/
759
760	void
761	poplocalvars(shinstance *psh)
762	{
763	struct localvar *lvp;
764	struct var *vp;
765
766	while ((lvp = psh->localvars) != NULL) {
767	psh->localvars = lvp->next;
768	vp = lvp->vp;
769	TRACE((psh, "poplocalvar %s", vp ? vp->text : "-"));
770	if (vp == NULL) { /* $- saved */
771	memcpy(psh->optlist, lvp->text, sizeof_optlist);
772	ckfree(lvp->text);
773	} else if ((lvp->flags & (VUNSET\|VSTRFIXED)) == VUNSET) {
774	(void)unsetvar(psh, vp->text, 0);
775	} else {
776	if (vp->func && (vp->flags & VNOFUNC) == 0)
777	(*vp->func)(psh, lvp->text + vp->name_len + 1);
778	if ((vp->flags & VTEXTFIXED) == 0)
779	ckfree(vp->text);
780	vp->flags = lvp->flags;
781	vp->text = lvp->text;
782	}
783	ckfree(lvp);
784	}
785	}
786
787
788	int
789	setvarcmd(shinstance psh, int argc, char *argv)
790	{
791	if (argc <= 2)
792	return unsetcmd(psh, argc, argv);
793	else if (argc == 3)
794	setvar(psh, argv[1], argv[2], 0);
795	else
796	error(psh, "List assignment not implemented");
797	return 0;
798	}
799
800
801	/*
802	* The unset builtin command. We unset the function before we unset the
803	* variable to allow a function to be unset when there is a readonly variable
804	* with the same name.
805	*/
806
807	int
808	unsetcmd(shinstance psh, int argc, char *argv)
809	{
810	char **ap;
811	int i;
812	int flg_func = 0;
813	int flg_var = 0;
814	int ret = 0;
815
816	while ((i = nextopt(psh, "evf")) != '\0') {
817	if (i == 'f')
818	flg_func = 1;
819	else
820	flg_var = i;
821	}
822	if (flg_func == 0 && flg_var == 0)
823	flg_var = 1;
824
825	for (ap = psh->argptr; *ap ; ap++) {
826	if (flg_func)
827	ret \|= unsetfunc(psh, *ap);
828	if (flg_var)
829	ret \|= unsetvar(psh, *ap, flg_var == 'e');
830	}
831	return ret;
832	}
833
834
835	/*
836	* Unset the specified variable.
837	*/
838
839	int
840	unsetvar(shinstance psh, const char s, int unexport)
841	{
842	struct var **vpp;
843	struct var *vp;
844
845	vp = find_var(psh, s, &vpp, NULL);
846	if (vp == NULL)
847	return 1;
848
849	if (vp->flags & VREADONLY)
850	return (1);
851
852	INTOFF;
853	if (unexport) {
854	vp->flags &= ~VEXPORT;
855	} else {
856	if (vp->text[vp->name_len + 1] != '\0')
857	setvar(psh, s, nullstr, 0);
858	vp->flags &= ~VEXPORT;
859	vp->flags \|= VUNSET;
860	if ((vp->flags & VSTRFIXED) == 0) {
861	if ((vp->flags & VTEXTFIXED) == 0)
862	ckfree(vp->text);
863	*vpp = vp->next;
864	ckfree(vp);
865	}
866	}
867	INTON;
868	return 0;
869	}
870
871
872	/*
873	* Returns true if the two strings specify the same varable. The first
874	* variable name is terminated by '='; the second may be terminated by
875	* either '=' or '\0'.
876	*/
877
878	STATIC int
879	strequal(const char p, const char q)
880	{
881	while (p == q++) {
882	if (*p++ == '=')
883	return 1;
884	}
885	if (p == '=' && (q - 1) == '\0')
886	return 1;
887	return 0;
888	}
889
890	/*
891	* Search for a variable.
892	* 'name' may be terminated by '=' or a NUL.
893	* vppp is set to the pointer to vp, or the list head if vp isn't found
894	* lenp is set to the number of charactets in 'name'
895	*/
896
897	STATIC struct var *
898	find_var(shinstance psh, const char name, struct var **vppp, int lenp)
899	{
900	unsigned int hashval;
901	int len;
902	struct var vp, *vpp;
903	const char *p = name;
904
905	hashval = 0;
906	while (p && p != '=')
907	hashval = 2 * hashval + (unsigned char)*p++;
908	len = (int)(p - name);
909
910	if (lenp)
911	*lenp = len;
912	vpp = &psh->vartab[hashval % VTABSIZE];
913	if (vppp)
914	*vppp = vpp;
915
916	for (vp = vpp ; vp ; vpp = &vp->next, vp = vpp) {
917	if (vp->name_len != len)
918	continue;
919	if (memcmp(vp->text, name, len) != 0)
920	continue;
921	if (vppp)
922	*vppp = vpp;
923	return vp;
924	}
925	return NULL;
926	}

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