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source: trunk/src/ash/var.c@ 657

Last change on this file since 657 was 637, checked in by bird, 19 years ago
Path != PATH. stupid stupid windows idiots.
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File size: 19.0 KB

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

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