xref: /dragonfly/bin/sh/var.c (revision 32931063) 
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  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by the University of
19  *	California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  *
36  * @(#)var.c	8.3 (Berkeley) 5/4/95
37  * $FreeBSD: src/bin/sh/var.c,v 1.61 2011/06/12 23:06:04 jilles Exp $
38  */
39 
40 #include <unistd.h>
41 #include <stdlib.h>
42 
43 /*
44  * Shell variables.
45  */
46 
47 #include <locale.h>
48 #include <langinfo.h>
49 #include <paths.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 struct var vterm;
84 #endif
85 struct var vifs;
86 struct var vmail;
87 struct var vmpath;
88 struct var vpath;
89 struct var vppid;
90 struct var vps1;
91 struct var vps2;
92 struct var vps4;
93 struct var vvers;
94 static struct var voptind;
95 
96 int forcelocal;
97 
98 static const struct varinit varinit[] = {
99 #ifndef NO_HISTORY
100 	{ &vhistsize,	VUNSET,				"HISTSIZE=",
101 	  sethistsize },
102 #endif
103 	{ &vifs,	0,				"IFS= \t\n",
104 	  NULL },
105 	{ &vmail,	VUNSET,				"MAIL=",
106 	  NULL },
107 	{ &vmpath,	VUNSET,				"MAILPATH=",
108 	  NULL },
109 	{ &vpath,	0,				"PATH=" _PATH_DEFPATH,
110 	  changepath },
111 	{ &vppid,	VUNSET,				"PPID=",
112 	  NULL },
113 	/*
114 	 * vps1 depends on uid
115 	 */
116 	{ &vps2,	0,				"PS2=> ",
117 	  NULL },
118 	{ &vps4,	0,				"PS4=+ ",
119 	  NULL },
120 #ifndef NO_HISTORY
121 	{ &vterm,	VUNSET,				"TERM=",
122 	  setterm },
123 #endif
124 	{ &voptind,	0,				"OPTIND=1",
125 	  getoptsreset },
126 	{ NULL,	0,				NULL,
127 	  NULL }
128 };
129 
130 static struct var *vartab[VTABSIZE];
131 
132 static const char *const locale_names[7] = {
133 	"LC_COLLATE", "LC_CTYPE", "LC_MONETARY",
134 	"LC_NUMERIC", "LC_TIME", "LC_MESSAGES", NULL
135 };
136 static const int locale_categories[7] = {
137 	LC_COLLATE, LC_CTYPE, LC_MONETARY, LC_NUMERIC, LC_TIME, LC_MESSAGES, 0
138 };
139 
140 static int varequal(const char *, const char *);
141 static struct var *find_var(const char *, struct var ***, int *);
142 static int localevar(const char *);
143 
144 /*
145  * Initialize the variable symbol tables and import the environment.
146  */
147 
148 #ifdef mkinit
149 INCLUDE "var.h"
150 MKINIT char **environ;
151 INIT {
152 	char **envp;
153 
154 	initvar();
155 	for (envp = environ ; *envp ; envp++) {
156 		if (strchr(*envp, '=')) {
157 			setvareq(*envp, VEXPORT|VTEXTFIXED);
158 		}
159 	}
160 }
161 #endif
162 
163 
164 /*
165  * This routine initializes the builtin variables.  It is called when the
166  * shell is initialized.
167  */
168 
169 void
170 initvar(void)
171 {
172 	char ppid[20];
173 	const struct varinit *ip;
174 	struct var *vp;
175 	struct var **vpp;
176 
177 	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
178 		if (find_var(ip->text, &vpp, &vp->name_len) != NULL)
179 			continue;
180 		vp->next = *vpp;
181 		*vpp = vp;
182 		vp->text = __DECONST(char *, ip->text);
183 		vp->flags = ip->flags | VSTRFIXED | VTEXTFIXED;
184 		vp->func = ip->func;
185 	}
186 	/*
187 	 * PS1 depends on uid
188 	 */
189 	if (find_var("PS1", &vpp, &vps1.name_len) == NULL) {
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 
205 int
206 setvarsafe(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 
230 void
231 setvar(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 
271 static int
272 localevar(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  * Sets/unsets an environment variable from a pointer that may actually be a
292  * pointer into environ where the string should not be manipulated.
293  */
294 static void
295 change_env(const char *s, int set)
296 {
297 	char *eqp;
298 	char *ss;
299 
300 	ss = savestr(s);
301 	if ((eqp = strchr(ss, '=')) != NULL)
302 		*eqp = '\0';
303 	if (set && eqp != NULL) {
304 		if (setenv(ss, eqp + 1, 1) != 0)
305 			error("setenv: cannot set %s=%s", ss, eqp + 1);
306 	} else
307 		unsetenv(ss);
308 	ckfree(ss);
309 }
310 
311 
312 /*
313  * Same as setvar except that the variable and value are passed in
314  * the first argument as name=value.  Since the first argument will
315  * be actually stored in the table, it should not be a string that
316  * will go away.
317  */
318 
319 void
320 setvareq(char *s, int flags)
321 {
322 	struct var *vp, **vpp;
323 	int nlen;
324 
325 	if (aflag)
326 		flags |= VEXPORT;
327 	if (forcelocal && !(flags & (VNOSET | VNOLOCAL)))
328 		mklocal(s);
329 	vp = find_var(s, &vpp, &nlen);
330 	if (vp != NULL) {
331 		if (vp->flags & VREADONLY)
332 			error("%.*s: is read only", vp->name_len, s);
333 		if (flags & VNOSET)
334 			return;
335 		INTOFF;
336 
337 		if (vp->func && (flags & VNOFUNC) == 0)
338 			(*vp->func)(s + vp->name_len + 1);
339 
340 		if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
341 			ckfree(vp->text);
342 
343 		vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
344 		vp->flags |= flags;
345 		vp->text = s;
346 
347 		/*
348 		 * We could roll this to a function, to handle it as
349 		 * a regular variable function callback, but why bother?
350 		 *
351 		 * Note: this assumes iflag is not set to 1 initially.
352 		 * As part of init(), this is called before arguments
353 		 * are looked at.
354 		 */
355 		if ((vp == &vmpath || (vp == &vmail && ! mpathset())) &&
356 		    iflag == 1)
357 			chkmail(1);
358 		if ((vp->flags & VEXPORT) && localevar(s)) {
359 			change_env(s, 1);
360 			setlocale(LC_ALL, "");
361 			updatecharset();
362 		}
363 		INTON;
364 		return;
365 	}
366 	/* not found */
367 	if (flags & VNOSET)
368 		return;
369 	vp = ckmalloc(sizeof (*vp));
370 	vp->flags = flags;
371 	vp->text = s;
372 	vp->name_len = nlen;
373 	vp->next = *vpp;
374 	vp->func = NULL;
375 	INTOFF;
376 	*vpp = vp;
377 	if ((vp->flags & VEXPORT) && localevar(s)) {
378 		change_env(s, 1);
379 		setlocale(LC_ALL, "");
380 		updatecharset();
381 	}
382 	INTON;
383 }
384 
385 
386 
387 /*
388  * Process a linked list of variable assignments.
389  */
390 
391 void
392 listsetvar(struct strlist *list, int flags)
393 {
394 	struct strlist *lp;
395 
396 	INTOFF;
397 	for (lp = list ; lp ; lp = lp->next) {
398 		setvareq(savestr(lp->text), flags);
399 	}
400 	INTON;
401 }
402 
403 
404 
405 /*
406  * Find the value of a variable.  Returns NULL if not set.
407  */
408 
409 char *
410 lookupvar(const char *name)
411 {
412 	struct var *v;
413 
414 	v = find_var(name, NULL, NULL);
415 	if (v == NULL || v->flags & VUNSET)
416 		return NULL;
417 	return v->text + v->name_len + 1;
418 }
419 
420 
421 
422 /*
423  * Search the environment of a builtin command.  If the second argument
424  * is nonzero, return the value of a variable even if it hasn't been
425  * exported.
426  */
427 
428 char *
429 bltinlookup(const char *name, int doall)
430 {
431 	struct strlist *sp;
432 	struct var *v;
433 	char *result;
434 
435 	result = NULL;
436 	for (sp = cmdenviron ; sp ; sp = sp->next) {
437 		if (varequal(sp->text, name))
438 			result = strchr(sp->text, '=') + 1;
439 	}
440 	if (result != NULL)
441 		return result;
442 
443 	v = find_var(name, NULL, NULL);
444 	if (v == NULL || v->flags & VUNSET ||
445 	    (!doall && (v->flags & VEXPORT) == 0))
446 		return NULL;
447 	return v->text + v->name_len + 1;
448 }
449 
450 
451 /*
452  * Set up locale for a builtin (LANG/LC_* assignments).
453  */
454 void
455 bltinsetlocale(void)
456 {
457 	struct strlist *lp;
458 	int act = 0;
459 	char *loc, *locdef;
460 	int i;
461 
462 	for (lp = cmdenviron ; lp ; lp = lp->next) {
463 		if (localevar(lp->text)) {
464 			act = 1;
465 			break;
466 		}
467 	}
468 	if (!act)
469 		return;
470 	loc = bltinlookup("LC_ALL", 0);
471 	INTOFF;
472 	if (loc != NULL) {
473 		setlocale(LC_ALL, loc);
474 		INTON;
475 		updatecharset();
476 		return;
477 	}
478 	locdef = bltinlookup("LANG", 0);
479 	for (i = 0; locale_names[i] != NULL; i++) {
480 		loc = bltinlookup(locale_names[i], 0);
481 		if (loc == NULL)
482 			loc = locdef;
483 		if (loc != NULL)
484 			setlocale(locale_categories[i], loc);
485 	}
486 	INTON;
487 	updatecharset();
488 }
489 
490 /*
491  * Undo the effect of bltinlocaleset().
492  */
493 void
494 bltinunsetlocale(void)
495 {
496 	struct strlist *lp;
497 
498 	INTOFF;
499 	for (lp = cmdenviron ; lp ; lp = lp->next) {
500 		if (localevar(lp->text)) {
501 			setlocale(LC_ALL, "");
502 			updatecharset();
503 			return;
504 		}
505 	}
506 	INTON;
507 }
508 
509 /*
510  * Update the localeisutf8 flag.
511  */
512 void
513 updatecharset(void)
514 {
515 	char *charset;
516 
517 	charset = nl_langinfo(CODESET);
518 	localeisutf8 = !strcmp(charset, "UTF-8");
519 }
520 
521 void
522 initcharset(void)
523 {
524 	updatecharset();
525 	initial_localeisutf8 = localeisutf8;
526 }
527 
528 /*
529  * Generate a list of exported variables.  This routine is used to construct
530  * the third argument to execve when executing a program.
531  */
532 
533 char **
534 environment(void)
535 {
536 	int nenv;
537 	struct var **vpp;
538 	struct var *vp;
539 	char **env, **ep;
540 
541 	nenv = 0;
542 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
543 		for (vp = *vpp ; vp ; vp = vp->next)
544 			if (vp->flags & VEXPORT)
545 				nenv++;
546 	}
547 	ep = env = stalloc((nenv + 1) * sizeof *env);
548 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
549 		for (vp = *vpp ; vp ; vp = vp->next)
550 			if (vp->flags & VEXPORT)
551 				*ep++ = vp->text;
552 	}
553 	*ep = NULL;
554 	return env;
555 }
556 
557 
558 static int
559 var_compare(const void *a, const void *b)
560 {
561 	const char *const *sa, *const *sb;
562 
563 	sa = a;
564 	sb = b;
565 	/*
566 	 * This compares two var=value strings which creates a different
567 	 * order from what you would probably expect.  POSIX is somewhat
568 	 * ambiguous on what should be sorted exactly.
569 	 */
570 	return strcoll(*sa, *sb);
571 }
572 
573 
574 /*
575  * Command to list all variables which are set.  This is invoked from the
576  * set command when it is called without any options or operands.
577  */
578 
579 int
580 showvarscmd(int argc __unused, char **argv __unused)
581 {
582 	struct var **vpp;
583 	struct var *vp;
584 	const char *s;
585 	const char **vars;
586 	int i, n;
587 
588 	/*
589 	 * POSIX requires us to sort the variables.
590 	 */
591 	n = 0;
592 	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
593 		for (vp = *vpp; vp; vp = vp->next) {
594 			if (!(vp->flags & VUNSET))
595 				n++;
596 		}
597 	}
598 
599 	INTON;
600 	vars = ckmalloc(n * sizeof(*vars));
601 	i = 0;
602 	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
603 		for (vp = *vpp; vp; vp = vp->next) {
604 			if (!(vp->flags & VUNSET))
605 				vars[i++] = vp->text;
606 		}
607 	}
608 
609 	qsort(vars, n, sizeof(*vars), var_compare);
610 	for (i = 0; i < n; i++) {
611 		s = strchr(vars[i], '=');
612 		s++;
613 		outbin(vars[i], s - vars[i], out1);
614 		out1qstr(s);
615 		out1c('\n');
616 	}
617 	ckfree(vars);
618 	INTOFF;
619 
620 	return 0;
621 }
622 
623 
624 
625 /*
626  * The export and readonly commands.
627  */
628 
629 int
630 exportcmd(int argc, char **argv)
631 {
632 	struct var **vpp;
633 	struct var *vp;
634 	char *name;
635 	char *p;
636 	char *cmdname;
637 	int ch, values;
638 	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
639 
640 	cmdname = argv[0];
641 	optreset = optind = 1;
642 	opterr = 0;
643 	values = 0;
644 	while ((ch = getopt(argc, argv, "p")) != -1) {
645 		switch (ch) {
646 		case 'p':
647 			values = 1;
648 			break;
649 		case '?':
650 		default:
651 			error("unknown option: -%c", optopt);
652 		}
653 	}
654 	argc -= optind;
655 	argv += optind;
656 
657 	if (values && argc != 0)
658 		error("-p requires no arguments");
659 	if (argc != 0) {
660 		while ((name = *argv++) != NULL) {
661 			if ((p = strchr(name, '=')) != NULL) {
662 				p++;
663 			} else {
664 				vp = find_var(name, NULL, NULL);
665 				if (vp != NULL) {
666 					vp->flags |= flag;
667 					if ((vp->flags & VEXPORT) && localevar(vp->text)) {
668 						change_env(vp->text, 1);
669 						setlocale(LC_ALL, "");
670 						updatecharset();
671 					}
672 					continue;
673 				}
674 			}
675 			setvar(name, p, flag);
676 		}
677 	} else {
678 		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
679 			for (vp = *vpp ; vp ; vp = vp->next) {
680 				if (vp->flags & flag) {
681 					if (values) {
682 						out1str(cmdname);
683 						out1c(' ');
684 					}
685 					if (values && !(vp->flags & VUNSET)) {
686 						outbin(vp->text,
687 						    vp->name_len + 1, out1);
688 						out1qstr(vp->text +
689 						    vp->name_len + 1);
690 					} else
691 						outbin(vp->text, vp->name_len,
692 						    out1);
693 					out1c('\n');
694 				}
695 			}
696 		}
697 	}
698 	return 0;
699 }
700 
701 
702 /*
703  * The "local" command.
704  */
705 
706 int
707 localcmd(int argc __unused, char **argv __unused)
708 {
709 	char *name;
710 
711 	if (! in_function())
712 		error("Not in a function");
713 	while ((name = *argptr++) != NULL) {
714 		mklocal(name);
715 	}
716 	return 0;
717 }
718 
719 
720 /*
721  * Make a variable a local variable.  When a variable is made local, it's
722  * value and flags are saved in a localvar structure.  The saved values
723  * will be restored when the shell function returns.  We handle the name
724  * "-" as a special case.
725  */
726 
727 void
728 mklocal(char *name)
729 {
730 	struct localvar *lvp;
731 	struct var **vpp;
732 	struct var *vp;
733 
734 	INTOFF;
735 	lvp = ckmalloc(sizeof (struct localvar));
736 	if (name[0] == '-' && name[1] == '\0') {
737 		lvp->text = ckmalloc(sizeof optlist);
738 		memcpy(lvp->text, optlist, sizeof optlist);
739 		vp = NULL;
740 	} else {
741 		vp = find_var(name, &vpp, NULL);
742 		if (vp == NULL) {
743 			if (strchr(name, '='))
744 				setvareq(savestr(name), VSTRFIXED | VNOLOCAL);
745 			else
746 				setvar(name, NULL, VSTRFIXED | VNOLOCAL);
747 			vp = *vpp;	/* the new variable */
748 			lvp->text = NULL;
749 			lvp->flags = VUNSET;
750 		} else {
751 			lvp->text = vp->text;
752 			lvp->flags = vp->flags;
753 			vp->flags |= VSTRFIXED|VTEXTFIXED;
754 			if (name[vp->name_len] == '=')
755 				setvareq(savestr(name), VNOLOCAL);
756 		}
757 	}
758 	lvp->vp = vp;
759 	lvp->next = localvars;
760 	localvars = lvp;
761 	INTON;
762 }
763 
764 
765 /*
766  * Called after a function returns.
767  */
768 
769 void
770 poplocalvars(void)
771 {
772 	struct localvar *lvp;
773 	struct var *vp;
774 
775 	while ((lvp = localvars) != NULL) {
776 		localvars = lvp->next;
777 		vp = lvp->vp;
778 		if (vp == NULL) {	/* $- saved */
779 			memcpy(optlist, lvp->text, sizeof optlist);
780 			ckfree(lvp->text);
781 			optschanged();
782 		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
783 			unsetvar(vp->text);
784 		} else {
785 			if ((vp->flags & VTEXTFIXED) == 0)
786 				ckfree(vp->text);
787 			vp->flags = lvp->flags;
788 			vp->text = lvp->text;
789 		}
790 		ckfree(lvp);
791 	}
792 }
793 
794 
795 int
796 setvarcmd(int argc, char **argv)
797 {
798 	if (argc <= 2)
799 		return unsetcmd(argc, argv);
800 	else if (argc == 3)
801 		setvar(argv[1], argv[2], 0);
802 	else
803 		error("too many arguments");
804 	return 0;
805 }
806 
807 
808 /*
809  * The unset builtin command.
810  */
811 
812 int
813 unsetcmd(int argc __unused, char **argv __unused)
814 {
815 	char **ap;
816 	int i;
817 	int flg_func = 0;
818 	int flg_var = 0;
819 	int ret = 0;
820 
821 	while ((i = nextopt("vf")) != '\0') {
822 		if (i == 'f')
823 			flg_func = 1;
824 		else
825 			flg_var = 1;
826 	}
827 	if (flg_func == 0 && flg_var == 0)
828 		flg_var = 1;
829 
830 	for (ap = argptr; *ap ; ap++) {
831 		if (flg_func)
832 			ret |= unsetfunc(*ap);
833 		if (flg_var)
834 			ret |= unsetvar(*ap);
835 	}
836 	return ret;
837 }
838 
839 
840 /*
841  * Unset the specified variable.
842  */
843 
844 int
845 unsetvar(const char *s)
846 {
847 	struct var **vpp;
848 	struct var *vp;
849 
850 	vp = find_var(s, &vpp, NULL);
851 	if (vp == NULL)
852 		return (0);
853 	if (vp->flags & VREADONLY)
854 		return (1);
855 	INTOFF;
856 	if (vp->text[vp->name_len + 1] != '\0')
857 		setvar(s, nullstr, 0);
858 	if ((vp->flags & VEXPORT) && localevar(vp->text)) {
859 		change_env(__DECONST(char *, s), 0);
860 		setlocale(LC_ALL, "");
861 		updatecharset();
862 	}
863 	vp->flags &= ~VEXPORT;
864 	vp->flags |= VUNSET;
865 	if ((vp->flags & VSTRFIXED) == 0) {
866 		if ((vp->flags & VTEXTFIXED) == 0)
867 			ckfree(vp->text);
868 		*vpp = vp->next;
869 		ckfree(vp);
870 	}
871 	INTON;
872 	return (0);
873 }
874 
875 
876 
877 /*
878  * Returns true if the two strings specify the same variable.  The first
879  * variable name is terminated by '='; the second may be terminated by
880  * either '=' or '\0'.
881  */
882 
883 static int
884 varequal(const char *p, const char *q)
885 {
886 	while (*p == *q++) {
887 		if (*p++ == '=')
888 			return 1;
889 	}
890 	if (*p == '=' && *(q - 1) == '\0')
891 		return 1;
892 	return 0;
893 }
894 
895 /*
896  * Search for a variable.
897  * 'name' may be terminated by '=' or a NUL.
898  * vppp is set to the pointer to vp, or the list head if vp isn't found
899  * lenp is set to the number of characters in 'name'
900  */
901 
902 static struct var *
903 find_var(const char *name, struct var ***vppp, int *lenp)
904 {
905 	unsigned int hashval;
906 	int len;
907 	struct var *vp, **vpp;
908 	const char *p = name;
909 
910 	hashval = 0;
911 	while (*p && *p != '=')
912 		hashval = 2 * hashval + (unsigned char)*p++;
913 	len = p - name;
914 
915 	if (lenp)
916 		*lenp = len;
917 	vpp = &vartab[hashval % VTABSIZE];
918 	if (vppp)
919 		*vppp = vpp;
920 
921 	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
922 		if (vp->name_len != len)
923 			continue;
924 		if (memcmp(vp->text, name, len) != 0)
925 			continue;
926 		if (vppp)
927 			*vppp = vpp;
928 		return vp;
929 	}
930 	return NULL;
931 }
932