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source: trunk/src/ash/var.c@ 819

Last change on this file since 819 was 809, checked in by bird, 19 years ago
Solaris + cleanup.
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File size: 19.1 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	#ifdef HAVE_SYS_CDEFS_H
36	#include <sys/cdefs.h>
37	#endif
38	#ifndef lint
39	#if 0
40	static char sccsid[] = "@(#)var.c 8.3 (Berkeley) 5/4/95";
41	#else
42	__RCSID("$NetBSD: var.c,v 1.36 2004/10/06 10:23:43 enami Exp $");
43	#endif
44	#endif /* not lint */
45
46	#include <unistd.h>
47	#include <stdlib.h>
48	#include <strings.h>
49	#ifndef __sun__
50	#include <paths.h>
51	#else
52	#define _PATH_DEFPATH "/usr/bin:/usr/sbin"
53	#include <iso/limits_iso.h>
54	#endif
55
56	#ifdef PC_OS2_LIBPATHS
57	#define INCL_BASE
58	#include <os2.h>
59
60	#ifndef LIBPATHSTRICT
61	#define LIBPATHSTRICT 3
62	#endif
63
64	extern APIRET
65	#ifdef APIENTRY
66	APIENTRY
67	#endif
68	DosQueryHeaderInfo(HMODULE hmod, ULONG ulIndex, PVOID pvBuffer, ULONG cbBuffer, ULONG ulSubFunction);
69	#define QHINF_EXEINFO 1 /* NE exeinfo. */
70	#define QHINF_READRSRCTBL 2 /* Reads from the resource table. */
71	#define QHINF_READFILE 3 /* Reads from the executable file. */
72	#define QHINF_LIBPATHLENGTH 4 /* Gets the libpath length. */
73	#define QHINF_LIBPATH 5 /* Gets the entire libpath. */
74	#define QHINF_FIXENTRY 6 /* NE only */
75	#define QHINF_STE 7 /* NE only */
76	#define QHINF_MAPSEL 8 /* NE only */
77
78	#endif
79
80
81	/*
82	* Shell variables.
83	*/
84
85	#include "shell.h"
86	#include "output.h"
87	#include "expand.h"
88	#include "nodes.h" /* for other headers */
89	#include "eval.h" /* defines cmdenviron */
90	#include "exec.h"
91	#include "syntax.h"
92	#include "options.h"
93	#include "mail.h"
94	#include "var.h"
95	#include "memalloc.h"
96	#include "error.h"
97	#include "mystring.h"
98	#include "parser.h"
99	#include "show.h"
100	#ifndef SMALL
101	#include "myhistedit.h"
102	#endif
103
104	#ifdef SMALL
105	#define VTABSIZE 39
106	#else
107	#define VTABSIZE 517
108	#endif
109
110
111	struct varinit {
112	struct var *var;
113	int flags;
114	const char *text;
115	void (func)(const char );
116	};
117
118
119	#if ATTY
120	struct var vatty;
121	#endif
122	#ifndef SMALL
123	struct var vhistsize;
124	struct var vterm;
125	#endif
126	struct var vifs;
127	struct var vmail;
128	struct var vmpath;
129	struct var vpath;
130	#ifdef _MSC_VER
131	struct var vpath2;
132	#endif
133	struct var vps1;
134	struct var vps2;
135	struct var vps4;
136	struct var vvers;
137	struct var voptind;
138
139	#ifdef PC_OS2_LIBPATHS
140	static struct var libpath_vars[4];
141	static const char *libpath_envs[4] = {"LIBPATH=", "BEGINLIBPATH=", "ENDLIBPATH=", "LIBPATHSTRICT="};
142	#endif
143
144	const struct varinit varinit[] = {
145	#if ATTY
146	{ &vatty, VSTRFIXED\|VTEXTFIXED\|VUNSET, "ATTY=",
147	NULL },
148	#endif
149	#ifndef SMALL
150	{ &vhistsize, VSTRFIXED\|VTEXTFIXED\|VUNSET, "HISTSIZE=",
151	sethistsize },
152	#endif
153	{ &vifs, VSTRFIXED\|VTEXTFIXED, "IFS= \t\n",
154	NULL },
155	{ &vmail, VSTRFIXED\|VTEXTFIXED\|VUNSET, "MAIL=",
156	NULL },
157	{ &vmpath, VSTRFIXED\|VTEXTFIXED\|VUNSET, "MAILPATH=",
158	NULL },
159	{ &vpath, VSTRFIXED\|VTEXTFIXED, "PATH=" _PATH_DEFPATH,
160	changepath },
161	#ifdef _MSC_VER
162	{ &vpath2, VSTRFIXED\|VTEXTFIXED, "Path=",
163	changepath },
164	#endif
165	/*
166	* vps1 depends on uid
167	*/
168	{ &vps2, VSTRFIXED\|VTEXTFIXED, "PS2=> ",
169	NULL },
170	{ &vps4, VSTRFIXED\|VTEXTFIXED, "PS4=+ ",
171	NULL },
172	#ifndef SMALL
173	{ &vterm, VSTRFIXED\|VTEXTFIXED\|VUNSET, "TERM=",
174	setterm },
175	#endif
176	{ &voptind, VSTRFIXED\|VTEXTFIXED\|VNOFUNC, "OPTIND=1",
177	getoptsreset },
178	{ NULL, 0, NULL,
179	NULL }
180	};
181
182	struct var *vartab[VTABSIZE];
183
184	STATIC int strequal(const char , const char );
185	STATIC struct var find_var(const char , struct var **, int );
186
187	/*
188	* Initialize the varable symbol tables and import the environment
189	*/
190
191	#ifdef mkinit
192	INCLUDE "var.h"
193	MKINIT char **environ;
194	INIT {
195	char **envp;
196
197	initvar();
198	for (envp = environ ; *envp ; envp++) {
199	if (strchr(*envp, '=')) {
200	setvareq(*envp, VEXPORT\|VTEXTFIXED);
201	}
202	}
203	}
204	#endif
205
206
207	/*
208	* This routine initializes the builtin variables. It is called when the
209	* shell is initialized and again when a shell procedure is spawned.
210	*/
211
212	void
213	initvar(void)
214	{
215	const struct varinit *ip;
216	struct var *vp;
217	struct var **vpp;
218
219	#ifdef PC_OS2_LIBPATHS
220	char *psz = ckmalloc(2048);
221	int rc;
222	int i;
223	for (i = 0; i < 4; i++)
224	{
225	libpath_vars[i].flags = VSTRFIXED \| VOS2LIBPATH;
226	libpath_vars[i].func = NULL;
227
228	if (i > 0)
229	rc = DosQueryExtLIBPATH(psz, i);
230	else
231	{
232	rc = DosQueryHeaderInfo(NULLHANDLE, 0, psz, 2048, QHINF_LIBPATH);
233	libpath_vars[i].flags \|= VREADONLY;
234	}
235	if (!rc && *psz)
236	{
237	int cch1 = strlen(libpath_envs[i]);
238	int cch2 = strlen(psz) + 1;
239	libpath_vars[i].text = ckmalloc(cch1 + cch2);
240	memcpy(libpath_vars[i].text, libpath_envs[i], cch1);
241	memcpy(libpath_vars[i].text + cch1, psz, cch2);
242	}
243	else
244	{
245	libpath_vars[i].flags \|= VUNSET \| VTEXTFIXED;
246	libpath_vars[i].text = (char*)libpath_envs[i];
247	}
248	if (find_var(libpath_vars[i].text, &vpp, &libpath_vars[i].name_len) != NULL)
249	continue;
250	libpath_vars[i].next = *vpp;
251	*vpp = &libpath_vars[i];
252	}
253	free(psz);
254	#endif
255
256	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
257	if (find_var(ip->text, &vpp, &vp->name_len) != NULL)
258	continue;
259	vp->next = *vpp;
260	*vpp = vp;
261	vp->text = strdup(ip->text);
262	vp->flags = ip->flags;
263	vp->func = ip->func;
264	}
265	/*
266	* PS1 depends on uid
267	*/
268	if (find_var("PS1", &vpp, &vps1.name_len) == NULL) {
269	vps1.next = *vpp;
270	*vpp = &vps1;
271	vps1.text = strdup(geteuid() ? "PS1=$ " : "PS1=# ");
272	vps1.flags = VSTRFIXED\|VTEXTFIXED;
273	}
274	}
275
276	/*
277	* Safe version of setvar, returns 1 on success 0 on failure.
278	*/
279
280	int
281	setvarsafe(const char name, const char val, int flags)
282	{
283	struct jmploc jmploc;
284	struct jmploc *volatile savehandler = handler;
285	int err = 0;
286	#ifdef __GNUC__
287	(void) &err;
288	#endif
289
290	if (setjmp(jmploc.loc))
291	err = 1;
292	else {
293	handler = &jmploc;
294	setvar(name, val, flags);
295	}
296	handler = savehandler;
297	return err;
298	}
299
300	/*
301	* Set the value of a variable. The flags argument is ored with the
302	* flags of the variable. If val is NULL, the variable is unset.
303	*/
304
305	void
306	setvar(const char name, const char val, int flags)
307	{
308	const char *p;
309	const char *q;
310	char *d;
311	int len;
312	int namelen;
313	char *nameeq;
314	int isbad;
315
316	isbad = 0;
317	p = name;
318	if (! is_name(*p))
319	isbad = 1;
320	p++;
321	for (;;) {
322	if (! is_in_name(*p)) {
323	if (p == '\0' \|\| p == '=')
324	break;
325	isbad = 1;
326	}
327	p++;
328	}
329	namelen = p - name;
330	if (isbad)
331	error("%.*s: bad variable name", namelen, name);
332	len = namelen + 2; /* 2 is space for '=' and '\0' */
333	if (val == NULL) {
334	flags \|= VUNSET;
335	} else {
336	len += strlen(val);
337	}
338	d = nameeq = ckmalloc(len);
339	q = name;
340	while (--namelen >= 0)
341	d++ = q++;
342	*d++ = '=';
343	*d = '\0';
344	if (val)
345	scopy(val, d);
346	setvareq(nameeq, flags);
347	}
348
349
350
351	/*
352	* Same as setvar except that the variable and value are passed in
353	* the first argument as name=value. Since the first argument will
354	* be actually stored in the table, it should not be a string that
355	* will go away.
356	*/
357
358	void
359	setvareq(char *s, int flags)
360	{
361	struct var vp, *vpp;
362	int nlen;
363
364	if (aflag)
365	flags \|= VEXPORT;
366	vp = find_var(s, &vpp, &nlen);
367	if (vp != NULL) {
368	if (vp->flags & VREADONLY)
369	error("%.*s: is read only", vp->name_len, s);
370	if (flags & VNOSET)
371	return;
372	INTOFF;
373
374	if (vp->func && (flags & VNOFUNC) == 0)
375	(*vp->func)(s + vp->name_len + 1);
376
377	if ((vp->flags & (VTEXTFIXED\|VSTACK)) == 0)
378	ckfree(vp->text);
379
380	vp->flags &= ~(VTEXTFIXED\|VSTACK\|VUNSET);
381	vp->flags \|= flags & ~VNOFUNC;
382	vp->text = s;
383	#ifdef PC_OS2_LIBPATHS
384	if ((vp->flags & VOS2LIBPATH) && (vp->flags & VEXPORT))
385	vp->flags &= ~VEXPORT;
386	#endif
387
388	/*
389	* We could roll this to a function, to handle it as
390	* a regular variable function callback, but why bother?
391	*/
392	if (vp == &vmpath \|\| (vp == &vmail && ! mpathset()))
393	chkmail(1);
394	INTON;
395	return;
396	}
397	/* not found */
398	if (flags & VNOSET)
399	return;
400	vp = ckmalloc(sizeof (*vp));
401	vp->flags = flags & ~VNOFUNC;
402	vp->text = s;
403	vp->name_len = nlen;
404	vp->next = *vpp;
405	vp->func = NULL;
406	*vpp = vp;
407	}
408
409
410
411	/*
412	* Process a linked list of variable assignments.
413	*/
414
415	void
416	listsetvar(struct strlist *list, int flags)
417	{
418	struct strlist *lp;
419
420	INTOFF;
421	for (lp = list ; lp ; lp = lp->next) {
422	setvareq(savestr(lp->text), flags);
423	}
424	INTON;
425	}
426
427	void
428	listmklocal(struct strlist *list, int flags)
429	{
430	struct strlist *lp;
431
432	for (lp = list ; lp ; lp = lp->next)
433	mklocal(lp->text, flags);
434	}
435
436
437	/*
438	* Find the value of a variable. Returns NULL if not set.
439	*/
440
441	char *
442	lookupvar(const char *name)
443	{
444	struct var *v;
445
446	v = find_var(name, NULL, NULL);
447	if (v == NULL \|\| v->flags & VUNSET)
448	return NULL;
449	return v->text + v->name_len + 1;
450	}
451
452
453
454	/*
455	* Search the environment of a builtin command. If the second argument
456	* is nonzero, return the value of a variable even if it hasn't been
457	* exported.
458	*/
459
460	char *
461	bltinlookup(const char *name, int doall)
462	{
463	struct strlist *sp;
464	struct var *v;
465
466	for (sp = cmdenviron ; sp ; sp = sp->next) {
467	if (strequal(sp->text, name))
468	return strchr(sp->text, '=') + 1;
469	}
470
471	v = find_var(name, NULL, NULL);
472
473	if (v == NULL \|\| v->flags & VUNSET \|\| (!doall && !(v->flags & VEXPORT)))
474	return NULL;
475	return v->text + v->name_len + 1;
476	}
477
478
479
480	/*
481	* Generate a list of exported variables. This routine is used to construct
482	* the third argument to execve when executing a program.
483	*/
484
485	char **
486	environment(void)
487	{
488	int nenv;
489	struct var **vpp;
490	struct var *vp;
491	char **env;
492	char **ep;
493
494	nenv = 0;
495	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
496	for (vp = *vpp ; vp ; vp = vp->next)
497	if (vp->flags & VEXPORT)
498	nenv++;
499	}
500	ep = env = stalloc((nenv + 1) * sizeof *env);
501	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
502	for (vp = *vpp ; vp ; vp = vp->next)
503	if (vp->flags & VEXPORT)
504	*ep++ = vp->text;
505	}
506	*ep = NULL;
507
508	#ifdef PC_OS2_LIBPATHS
509	/*
510	* Set the libpaths now as this is exec() time.
511	*/
512	for (nenv = 0; nenv < 3; nenv++)
513	DosSetExtLIBPATH(strchr(libpath_vars[nenv].text, '=') + 1, nenv);
514	#endif
515
516	return env;
517	}
518
519
520	/*
521	* Called when a shell procedure is invoked to clear out nonexported
522	* variables. It is also necessary to reallocate variables of with
523	* VSTACK set since these are currently allocated on the stack.
524	*/
525
526	#ifdef mkinit
527	void shprocvar(void);
528
529	SHELLPROC {
530	shprocvar();
531	}
532	#endif
533
534	void
535	shprocvar(void)
536	{
537	struct var **vpp;
538	struct var vp, *prev;
539
540	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
541	for (prev = vpp ; (vp = *prev) != NULL ; ) {
542	if ((vp->flags & VEXPORT) == 0) {
543	*prev = vp->next;
544	if ((vp->flags & VTEXTFIXED) == 0)
545	ckfree(vp->text);
546	if ((vp->flags & VSTRFIXED) == 0)
547	ckfree(vp);
548	} else {
549	if (vp->flags & VSTACK) {
550	vp->text = savestr(vp->text);
551	vp->flags &=~ VSTACK;
552	}
553	prev = &vp->next;
554	}
555	}
556	}
557	initvar();
558	}
559
560
561
562	/*
563	* Command to list all variables which are set. Currently this command
564	* is invoked from the set command when the set command is called without
565	* any variables.
566	*/
567
568	void
569	print_quoted(const char *p)
570	{
571	const char *q;
572
573	if (strcspn(p, "\|&;<>()$`\\\"' \t\n*?[]#~=%") == strlen(p)) {
574	out1fmt("%s", p);
575	return;
576	}
577	while (*p) {
578	if (*p == '\'') {
579	out1fmt("\\'");
580	p++;
581	continue;
582	}
583	q = index(p, '\'');
584	if (!q) {
585	out1fmt("'%s'", p );
586	return;
587	}
588	out1fmt("'%.*s'", (int)(q - p), p );
589	p = q;
590	}
591	}
592
593	static int
594	sort_var(const void v_v1, const void v_v2)
595	{
596	const struct var * const *v1 = v_v1;
597	const struct var * const *v2 = v_v2;
598
599	/* XXX Will anyone notice we include the '=' of the shorter name? */
600	return strcoll((v1)->text, (v2)->text);
601	}
602
603	/*
604	* POSIX requires that 'set' (but not export or readonly) output the
605	* variables in lexicographic order - by the locale's collating order (sigh).
606	* Maybe we could keep them in an ordered balanced binary tree
607	* instead of hashed lists.
608	* For now just roll 'em through qsort for printing...
609	*/
610
611	int
612	showvars(const char *name, int flag, int show_value)
613	{
614	struct var **vpp;
615	struct var *vp;
616	const char *p;
617
618	static struct var *list; / static in case we are interrupted */
619	static int list_len;
620	int count = 0;
621
622	if (!list) {
623	list_len = 32;
624	list = ckmalloc(list_len * sizeof *list);
625	}
626
627	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
628	for (vp = *vpp ; vp ; vp = vp->next) {
629	if (flag && !(vp->flags & flag))
630	continue;
631	if (vp->flags & VUNSET && !(show_value & 2))
632	continue;
633	if (count >= list_len) {
634	list = ckrealloc(list,
635	(list_len << 1) * sizeof *list);
636	list_len <<= 1;
637	}
638	list[count++] = vp;
639	}
640	}
641
642	qsort(list, count, sizeof *list, sort_var);
643
644	for (vpp = list; count--; vpp++) {
645	vp = *vpp;
646	if (name)
647	out1fmt("%s ", name);
648	for (p = vp->text ; *p != '=' ; p++)
649	out1c(*p);
650	if (!(vp->flags & VUNSET) && show_value) {
651	out1fmt("=");
652	print_quoted(++p);
653	}
654	out1c('\n');
655	}
656	return 0;
657	}
658
659
660
661	/*
662	* The export and readonly commands.
663	*/
664
665	int
666	exportcmd(int argc, char **argv)
667	{
668	struct var *vp;
669	char *name;
670	const char *p;
671	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
672	int pflag;
673
674	pflag = nextopt("p") == 'p' ? 3 : 0;
675	if (argc <= 1 \|\| pflag) {
676	showvars( pflag ? argv[0] : 0, flag, pflag );
677	return 0;
678	}
679
680	while ((name = *argptr++) != NULL) {
681	if ((p = strchr(name, '=')) != NULL) {
682	p++;
683	} else {
684	vp = find_var(name, NULL, NULL);
685	if (vp != NULL) {
686	vp->flags \|= flag;
687	continue;
688	}
689	}
690	setvar(name, p, flag);
691	}
692	return 0;
693	}
694
695
696	/*
697	* The "local" command.
698	*/
699
700	int
701	localcmd(int argc, char **argv)
702	{
703	char *name;
704
705	if (! in_function())
706	error("Not in a function");
707	while ((name = *argptr++) != NULL) {
708	mklocal(name, 0);
709	}
710	return 0;
711	}
712
713
714	/*
715	* Make a variable a local variable. When a variable is made local, it's
716	* value and flags are saved in a localvar structure. The saved values
717	* will be restored when the shell function returns. We handle the name
718	* "-" as a special case.
719	*/
720
721	void
722	mklocal(const char *name, int flags)
723	{
724	struct localvar *lvp;
725	struct var **vpp;
726	struct var *vp;
727
728	INTOFF;
729	lvp = ckmalloc(sizeof (struct localvar));
730	if (name[0] == '-' && name[1] == '\0') {
731	char *p;
732	p = ckmalloc(sizeof_optlist);
733	lvp->text = memcpy(p, optlist, sizeof_optlist);
734	vp = NULL;
735	} else {
736	vp = find_var(name, &vpp, NULL);
737	if (vp == NULL) {
738	if (strchr(name, '='))
739	setvareq(savestr(name), VSTRFIXED\|flags);
740	else
741	setvar(name, NULL, VSTRFIXED\|flags);
742	vp = vpp; / the new variable */
743	lvp->text = NULL;
744	lvp->flags = VUNSET;
745	} else {
746	lvp->text = vp->text;
747	lvp->flags = vp->flags;
748	vp->flags \|= VSTRFIXED\|VTEXTFIXED;
749	if (name[vp->name_len] == '=')
750	setvareq(savestr(name), flags);
751	}
752	}
753	lvp->vp = vp;
754	lvp->next = localvars;
755	localvars = lvp;
756	INTON;
757	}
758
759
760	/*
761	* Called after a function returns.
762	*/
763
764	void
765	poplocalvars(void)
766	{
767	struct localvar *lvp;
768	struct var *vp;
769
770	while ((lvp = localvars) != NULL) {
771	localvars = lvp->next;
772	vp = lvp->vp;
773	TRACE(("poplocalvar %s", vp ? vp->text : "-"));
774	if (vp == NULL) { /* $- saved */
775	memcpy(optlist, lvp->text, sizeof_optlist);
776	ckfree(lvp->text);
777	} else if ((lvp->flags & (VUNSET\|VSTRFIXED)) == VUNSET) {
778	(void)unsetvar(vp->text, 0);
779	} else {
780	if (vp->func && (vp->flags & VNOFUNC) == 0)
781	(*vp->func)(lvp->text + vp->name_len + 1);
782	if ((vp->flags & VTEXTFIXED) == 0)
783	ckfree(vp->text);
784	vp->flags = lvp->flags;
785	vp->text = lvp->text;
786	}
787	ckfree(lvp);
788	}
789	}
790
791
792	int
793	setvarcmd(int argc, char **argv)
794	{
795	if (argc <= 2)
796	return unsetcmd(argc, argv);
797	else if (argc == 3)
798	setvar(argv[1], argv[2], 0);
799	else
800	error("List assignment not implemented");
801	return 0;
802	}
803
804
805	/*
806	* The unset builtin command. We unset the function before we unset the
807	* variable to allow a function to be unset when there is a readonly variable
808	* with the same name.
809	*/
810
811	int
812	unsetcmd(int argc, char **argv)
813	{
814	char **ap;
815	int i;
816	int flg_func = 0;
817	int flg_var = 0;
818	int ret = 0;
819
820	while ((i = nextopt("evf")) != '\0') {
821	if (i == 'f')
822	flg_func = 1;
823	else
824	flg_var = i;
825	}
826	if (flg_func == 0 && flg_var == 0)
827	flg_var = 1;
828
829	for (ap = argptr; *ap ; ap++) {
830	if (flg_func)
831	ret \|= unsetfunc(*ap);
832	if (flg_var)
833	ret \|= unsetvar(*ap, flg_var == 'e');
834	}
835	return ret;
836	}
837
838
839	/*
840	* Unset the specified variable.
841	*/
842
843	int
844	unsetvar(const char *s, int unexport)
845	{
846	struct var **vpp;
847	struct var *vp;
848
849	vp = find_var(s, &vpp, NULL);
850	if (vp == NULL)
851	return 1;
852
853	if (vp->flags & VREADONLY)
854	return (1);
855
856	INTOFF;
857	if (unexport) {
858	vp->flags &= ~VEXPORT;
859	} else {
860	if (vp->text[vp->name_len + 1] != '\0')
861	setvar(s, nullstr, 0);
862	vp->flags &= ~VEXPORT;
863	vp->flags \|= VUNSET;
864	if ((vp->flags & VSTRFIXED) == 0) {
865	if ((vp->flags & VTEXTFIXED) == 0)
866	ckfree(vp->text);
867	*vpp = vp->next;
868	ckfree(vp);
869	}
870	}
871	INTON;
872	return 0;
873	}
874
875
876	/*
877	* Returns true if the two strings specify the same varable. The first
878	* variable name is terminated by '='; the second may be terminated by
879	* either '=' or '\0'.
880	*/
881
882	STATIC int
883	strequal(const char p, const char q)
884	{
885	while (p == q++) {
886	if (*p++ == '=')
887	return 1;
888	}
889	if (p == '=' && (q - 1) == '\0')
890	return 1;
891	return 0;
892	}
893
894	/*
895	* Search for a variable.
896	* 'name' may be terminated by '=' or a NUL.
897	* vppp is set to the pointer to vp, or the list head if vp isn't found
898	* lenp is set to the number of charactets in 'name'
899	*/
900
901	STATIC struct var *
902	find_var(const char name, struct var *vppp, int lenp)
903	{
904	unsigned int hashval;
905	int len;
906	struct var vp, *vpp;
907	const char *p = name;
908
909	hashval = 0;
910	while (p && p != '=')
911	hashval = 2 * hashval + (unsigned char)*p++;
912	len = p - name;
913
914	if (lenp)
915	*lenp = len;
916	vpp = &vartab[hashval % VTABSIZE];
917	if (vppp)
918	*vppp = vpp;
919
920	for (vp = vpp ; vp ; vpp = &vp->next, vp = vpp) {
921	if (vp->name_len != len)
922	continue;
923	if (memcmp(vp->text, name, len) != 0)
924	continue;
925	if (vppp)
926	*vppp = vpp;
927	return vp;
928	}
929	return NULL;
930	}

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