xref: /dragonfly/bin/sh/var.c (revision d4ef6694) 
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. 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  * @(#)var.c	8.3 (Berkeley) 5/4/95
33  * $FreeBSD: head/bin/sh/var.c 245689 2013-01-20 12:44:50Z jilles $
34  */
35 
36 #include <unistd.h>
37 #include <stdlib.h>
38 
39 /*
40  * Shell variables.
41  */
42 
43 #include <locale.h>
44 #include <langinfo.h>
45 #include <paths.h>
46 
47 #include "shell.h"
48 #include "output.h"
49 #include "expand.h"
50 #include "nodes.h"	/* for other headers */
51 #include "eval.h"	/* defines cmdenviron */
52 #include "exec.h"
53 #include "syntax.h"
54 #include "options.h"
55 #include "mail.h"
56 #include "var.h"
57 #include "memalloc.h"
58 #include "error.h"
59 #include "mystring.h"
60 #include "parser.h"
61 #include "builtins.h"
62 #ifndef NO_HISTORY
63 #include "myhistedit.h"
64 #endif
65 
66 
67 #define VTABSIZE 39
68 
69 
70 struct varinit {
71 	struct var *var;
72 	int flags;
73 	const char *text;
74 	void (*func)(const char *);
75 };
76 
77 
78 #ifndef NO_HISTORY
79 struct var vhistsize;
80 struct var vterm;
81 #endif
82 struct var vifs;
83 struct var vmail;
84 struct var vmpath;
85 struct var vpath;
86 struct var vppid;
87 struct var vps1;
88 struct var vps2;
89 struct var vps4;
90 struct var vvers;
91 static struct var voptind;
92 struct var vdisvfork;
93 
94 int forcelocal;
95 
96 static 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 	{ &vdisvfork,	VUNSET,				"SH_DISABLE_VFORK=",
125 	  NULL },
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 extern char **environ;
145 
146 /*
147  * This routine initializes the builtin variables and imports the environment.
148  * It is called when the shell is initialized.
149  */
150 
151 void
152 initvar(void)
153 {
154 	char ppid[20];
155 	const struct varinit *ip;
156 	struct var *vp;
157 	struct var **vpp;
158 	char **envp;
159 
160 	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
161 		if (find_var(ip->text, &vpp, &vp->name_len) != NULL)
162 			continue;
163 		vp->next = *vpp;
164 		*vpp = vp;
165 		vp->text = __DECONST(char *, ip->text);
166 		vp->flags = ip->flags | VSTRFIXED | VTEXTFIXED;
167 		vp->func = ip->func;
168 	}
169 	/*
170 	 * PS1 depends on uid
171 	 */
172 	if (find_var("PS1", &vpp, &vps1.name_len) == NULL) {
173 		vps1.next = *vpp;
174 		*vpp = &vps1;
175 		vps1.text = __DECONST(char *, geteuid() ? "PS1=$ " : "PS1=# ");
176 		vps1.flags = VSTRFIXED|VTEXTFIXED;
177 	}
178 	if ((vppid.flags & VEXPORT) == 0) {
179 		fmtstr(ppid, sizeof(ppid), "%d", (int)getppid());
180 		setvarsafe("PPID", ppid, 0);
181 	}
182 	for (envp = environ ; *envp ; envp++) {
183 		if (strchr(*envp, '=')) {
184 			setvareq(*envp, VEXPORT|VTEXTFIXED);
185 		}
186 	}
187 }
188 
189 /*
190  * Safe version of setvar, returns 1 on success 0 on failure.
191  */
192 
193 int
194 setvarsafe(const char *name, const char *val, int flags)
195 {
196 	struct jmploc jmploc;
197 	struct jmploc *const savehandler = handler;
198 	int err = 0;
199 	int inton;
200 
201 	inton = is_int_on();
202 	if (setjmp(jmploc.loc))
203 		err = 1;
204 	else {
205 		handler = &jmploc;
206 		setvar(name, val, flags);
207 	}
208 	handler = savehandler;
209 	SETINTON(inton);
210 	return err;
211 }
212 
213 /*
214  * Set the value of a variable.  The flags argument is stored with the
215  * flags of the variable.  If val is NULL, the variable is unset.
216  */
217 
218 void
219 setvar(const char *name, const char *val, int flags)
220 {
221 	const char *p;
222 	int len;
223 	int namelen;
224 	char *nameeq;
225 	int isbad;
226 
227 	isbad = 0;
228 	p = name;
229 	if (!is_name(*p))
230 		isbad = 1;
231 	p++;
232 	for (;;) {
233 		if (!is_in_name(*p)) {
234 			if (*p == '\0' || *p == '=')
235 				break;
236 			isbad = 1;
237 		}
238 		p++;
239 	}
240 	namelen = p - name;
241 	if (isbad)
242 		error("%.*s: bad variable name", namelen, name);
243 	len = namelen + 2;		/* 2 is space for '=' and '\0' */
244 	if (val == NULL) {
245 		flags |= VUNSET;
246 	} else {
247 		len += strlen(val);
248 	}
249 	nameeq = ckmalloc(len);
250 	memcpy(nameeq, name, namelen);
251 	nameeq[namelen] = '=';
252 	if (val)
253 		scopy(val, nameeq + namelen + 1);
254 	else
255 		nameeq[namelen + 1] = '\0';
256 	setvareq(nameeq, flags);
257 }
258 
259 static int
260 localevar(const char *s)
261 {
262 	const char *const *ss;
263 
264 	if (*s != 'L')
265 		return 0;
266 	if (varequal(s + 1, "ANG"))
267 		return 1;
268 	if (strncmp(s + 1, "C_", 2) != 0)
269 		return 0;
270 	if (varequal(s + 3, "ALL"))
271 		return 1;
272 	for (ss = locale_names; *ss ; ss++)
273 		if (varequal(s + 3, *ss + 3))
274 			return 1;
275 	return 0;
276 }
277 
278 /*
279  * Sets/unsets an environment variable from a pointer that may actually be a
280  * pointer into environ where the string should not be manipulated.
281  */
282 static void
283 change_env(const char *s, int set)
284 {
285 	char *eqp;
286 	char *ss;
287 
288 	ss = savestr(s);
289 	if ((eqp = strchr(ss, '=')) != NULL)
290 		*eqp = '\0';
291 	if (set && eqp != NULL) {
292 		if (setenv(ss, eqp + 1, 1) != 0)
293 			error("setenv: cannot set %s=%s", ss, eqp + 1);
294 	} else
295 		unsetenv(ss);
296 	ckfree(ss);
297 }
298 
299 
300 /*
301  * Same as setvar except that the variable and value are passed in
302  * the first argument as name=value.  Since the first argument will
303  * be actually stored in the table, it should not be a string that
304  * will go away.
305  */
306 
307 void
308 setvareq(char *s, int flags)
309 {
310 	struct var *vp, **vpp;
311 	int nlen;
312 
313 	if (aflag)
314 		flags |= VEXPORT;
315 	if (forcelocal && !(flags & (VNOSET | VNOLOCAL)))
316 		mklocal(s);
317 	vp = find_var(s, &vpp, &nlen);
318 	if (vp != NULL) {
319 		if (vp->flags & VREADONLY)
320 			error("%.*s: is read only", vp->name_len, s);
321 		if (flags & VNOSET)
322 			return;
323 		INTOFF;
324 
325 		if (vp->func && (flags & VNOFUNC) == 0)
326 			(*vp->func)(s + vp->name_len + 1);
327 
328 		if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
329 			ckfree(vp->text);
330 
331 		vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
332 		vp->flags |= flags;
333 		vp->text = s;
334 
335 		/*
336 		 * We could roll this to a function, to handle it as
337 		 * a regular variable function callback, but why bother?
338 		 *
339 		 * Note: this assumes iflag is not set to 1 initially.
340 		 * As part of initvar(), this is called before arguments
341 		 * are looked at.
342 		 */
343 		if ((vp == &vmpath || (vp == &vmail && ! mpathset())) &&
344 		    iflag == 1)
345 			chkmail(1);
346 		if ((vp->flags & VEXPORT) && localevar(s)) {
347 			change_env(s, 1);
348 			setlocale(LC_ALL, "");
349 			updatecharset();
350 		}
351 		INTON;
352 		return;
353 	}
354 	/* not found */
355 	if (flags & VNOSET)
356 		return;
357 	vp = ckmalloc(sizeof (*vp));
358 	vp->flags = flags;
359 	vp->text = s;
360 	vp->name_len = nlen;
361 	vp->next = *vpp;
362 	vp->func = NULL;
363 	INTOFF;
364 	*vpp = vp;
365 	if ((vp->flags & VEXPORT) && localevar(s)) {
366 		change_env(s, 1);
367 		setlocale(LC_ALL, "");
368 		updatecharset();
369 	}
370 	INTON;
371 }
372 
373 
374 
375 /*
376  * Process a linked list of variable assignments.
377  */
378 
379 void
380 listsetvar(struct strlist *list, int flags)
381 {
382 	struct strlist *lp;
383 
384 	INTOFF;
385 	for (lp = list ; lp ; lp = lp->next) {
386 		setvareq(savestr(lp->text), flags);
387 	}
388 	INTON;
389 }
390 
391 
392 
393 /*
394  * Find the value of a variable.  Returns NULL if not set.
395  */
396 
397 char *
398 lookupvar(const char *name)
399 {
400 	struct var *v;
401 
402 	v = find_var(name, NULL, NULL);
403 	if (v == NULL || v->flags & VUNSET)
404 		return NULL;
405 	return v->text + v->name_len + 1;
406 }
407 
408 
409 
410 /*
411  * Search the environment of a builtin command.  If the second argument
412  * is nonzero, return the value of a variable even if it hasn't been
413  * exported.
414  */
415 
416 char *
417 bltinlookup(const char *name, int doall)
418 {
419 	struct strlist *sp;
420 	struct var *v;
421 	char *result;
422 
423 	result = NULL;
424 	for (sp = cmdenviron ; sp ; sp = sp->next) {
425 		if (varequal(sp->text, name))
426 			result = strchr(sp->text, '=') + 1;
427 	}
428 	if (result != NULL)
429 		return result;
430 
431 	v = find_var(name, NULL, NULL);
432 	if (v == NULL || v->flags & VUNSET ||
433 	    (!doall && (v->flags & VEXPORT) == 0))
434 		return NULL;
435 	return v->text + v->name_len + 1;
436 }
437 
438 
439 /*
440  * Set up locale for a builtin (LANG/LC_* assignments).
441  */
442 void
443 bltinsetlocale(void)
444 {
445 	struct strlist *lp;
446 	int act = 0;
447 	char *loc, *locdef;
448 	int i;
449 
450 	for (lp = cmdenviron ; lp ; lp = lp->next) {
451 		if (localevar(lp->text)) {
452 			act = 1;
453 			break;
454 		}
455 	}
456 	if (!act)
457 		return;
458 	loc = bltinlookup("LC_ALL", 0);
459 	INTOFF;
460 	if (loc != NULL) {
461 		setlocale(LC_ALL, loc);
462 		INTON;
463 		updatecharset();
464 		return;
465 	}
466 	locdef = bltinlookup("LANG", 0);
467 	for (i = 0; locale_names[i] != NULL; i++) {
468 		loc = bltinlookup(locale_names[i], 0);
469 		if (loc == NULL)
470 			loc = locdef;
471 		if (loc != NULL)
472 			setlocale(locale_categories[i], loc);
473 	}
474 	INTON;
475 	updatecharset();
476 }
477 
478 /*
479  * Undo the effect of bltinlocaleset().
480  */
481 void
482 bltinunsetlocale(void)
483 {
484 	struct strlist *lp;
485 
486 	INTOFF;
487 	for (lp = cmdenviron ; lp ; lp = lp->next) {
488 		if (localevar(lp->text)) {
489 			setlocale(LC_ALL, "");
490 			updatecharset();
491 			return;
492 		}
493 	}
494 	INTON;
495 }
496 
497 /*
498  * Update the localeisutf8 flag.
499  */
500 void
501 updatecharset(void)
502 {
503 	char *charset;
504 
505 	charset = nl_langinfo(CODESET);
506 	localeisutf8 = !strcmp(charset, "UTF-8");
507 }
508 
509 void
510 initcharset(void)
511 {
512 	updatecharset();
513 	initial_localeisutf8 = localeisutf8;
514 }
515 
516 /*
517  * Generate a list of exported variables.  This routine is used to construct
518  * the third argument to execve when executing a program.
519  */
520 
521 char **
522 environment(void)
523 {
524 	int nenv;
525 	struct var **vpp;
526 	struct var *vp;
527 	char **env, **ep;
528 
529 	nenv = 0;
530 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
531 		for (vp = *vpp ; vp ; vp = vp->next)
532 			if (vp->flags & VEXPORT)
533 				nenv++;
534 	}
535 	ep = env = stalloc((nenv + 1) * sizeof *env);
536 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
537 		for (vp = *vpp ; vp ; vp = vp->next)
538 			if (vp->flags & VEXPORT)
539 				*ep++ = vp->text;
540 	}
541 	*ep = NULL;
542 	return env;
543 }
544 
545 
546 static int
547 var_compare(const void *a, const void *b)
548 {
549 	const char *const *sa, *const *sb;
550 
551 	sa = a;
552 	sb = b;
553 	/*
554 	 * This compares two var=value strings which creates a different
555 	 * order from what you would probably expect.  POSIX is somewhat
556 	 * ambiguous on what should be sorted exactly.
557 	 */
558 	return strcoll(*sa, *sb);
559 }
560 
561 
562 /*
563  * Command to list all variables which are set.  This is invoked from the
564  * set command when it is called without any options or operands.
565  */
566 
567 int
568 showvarscmd(int argc __unused, char **argv __unused)
569 {
570 	struct var **vpp;
571 	struct var *vp;
572 	const char *s;
573 	const char **vars;
574 	int i, n;
575 
576 	/*
577 	 * POSIX requires us to sort the variables.
578 	 */
579 	n = 0;
580 	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
581 		for (vp = *vpp; vp; vp = vp->next) {
582 			if (!(vp->flags & VUNSET))
583 				n++;
584 		}
585 	}
586 
587 	INTOFF;
588 	vars = ckmalloc(n * sizeof(*vars));
589 	i = 0;
590 	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
591 		for (vp = *vpp; vp; vp = vp->next) {
592 			if (!(vp->flags & VUNSET))
593 				vars[i++] = vp->text;
594 		}
595 	}
596 
597 	qsort(vars, n, sizeof(*vars), var_compare);
598 	for (i = 0; i < n; i++) {
599 		/*
600 		 * Skip improper variable names so the output remains usable as
601 		 * shell input.
602 		 */
603 		if (!isassignment(vars[i]))
604 			continue;
605 		s = strchr(vars[i], '=');
606 		s++;
607 		outbin(vars[i], s - vars[i], out1);
608 		out1qstr(s);
609 		out1c('\n');
610 	}
611 	ckfree(vars);
612 	INTON;
613 
614 	return 0;
615 }
616 
617 
618 
619 /*
620  * The export and readonly commands.
621  */
622 
623 int
624 exportcmd(int argc __unused, char **argv)
625 {
626 	struct var **vpp;
627 	struct var *vp;
628 	char **ap;
629 	char *name;
630 	char *p;
631 	char *cmdname;
632 	int ch, values;
633 	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
634 
635 	cmdname = argv[0];
636 	values = 0;
637 	while ((ch = nextopt("p")) != '\0') {
638 		switch (ch) {
639 		case 'p':
640 			values = 1;
641 			break;
642 		}
643 	}
644 
645 	if (values && *argptr != NULL)
646 		error("-p requires no arguments");
647 	if (*argptr != NULL) {
648 		for (ap = argptr; (name = *ap) != NULL; ap++) {
649 			if ((p = strchr(name, '=')) != NULL) {
650 				p++;
651 			} else {
652 				vp = find_var(name, NULL, NULL);
653 				if (vp != NULL) {
654 					vp->flags |= flag;
655 					if ((vp->flags & VEXPORT) && localevar(vp->text)) {
656 						change_env(vp->text, 1);
657 						setlocale(LC_ALL, "");
658 						updatecharset();
659 					}
660 					continue;
661 				}
662 			}
663 			setvar(name, p, flag);
664 		}
665 	} else {
666 		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
667 			for (vp = *vpp ; vp ; vp = vp->next) {
668 				if (vp->flags & flag) {
669 					if (values) {
670 						/*
671 						 * Skip improper variable names
672 						 * so the output remains usable
673 						 * as shell input.
674 						 */
675 						if (!isassignment(vp->text))
676 							continue;
677 						out1str(cmdname);
678 						out1c(' ');
679 					}
680 					if (values && !(vp->flags & VUNSET)) {
681 						outbin(vp->text,
682 						    vp->name_len + 1, out1);
683 						out1qstr(vp->text +
684 						    vp->name_len + 1);
685 					} else
686 						outbin(vp->text, vp->name_len,
687 						    out1);
688 					out1c('\n');
689 				}
690 			}
691 		}
692 	}
693 	return 0;
694 }
695 
696 
697 /*
698  * The "local" command.
699  */
700 
701 int
702 localcmd(int argc __unused, char **argv __unused)
703 {
704 	char *name;
705 
706 	if (! in_function())
707 		error("Not in a function");
708 	while ((name = *argptr++) != NULL) {
709 		mklocal(name);
710 	}
711 	return 0;
712 }
713 
714 
715 /*
716  * Make a variable a local variable.  When a variable is made local, it's
717  * value and flags are saved in a localvar structure.  The saved values
718  * will be restored when the shell function returns.  We handle the name
719  * "-" as a special case.
720  */
721 
722 void
723 mklocal(char *name)
724 {
725 	struct localvar *lvp;
726 	struct var **vpp;
727 	struct var *vp;
728 
729 	INTOFF;
730 	lvp = ckmalloc(sizeof (struct localvar));
731 	if (name[0] == '-' && name[1] == '\0') {
732 		lvp->text = ckmalloc(sizeof optlist);
733 		memcpy(lvp->text, 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 | VNOLOCAL);
740 			else
741 				setvar(name, NULL, VSTRFIXED | VNOLOCAL);
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), VNOLOCAL);
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 		if (vp == NULL) {	/* $- saved */
774 			memcpy(optlist, lvp->text, sizeof optlist);
775 			ckfree(lvp->text);
776 			optschanged();
777 		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
778 			unsetvar(vp->text);
779 		} else {
780 			if ((vp->flags & VTEXTFIXED) == 0)
781 				ckfree(vp->text);
782 			vp->flags = lvp->flags;
783 			vp->text = lvp->text;
784 		}
785 		ckfree(lvp);
786 	}
787 }
788 
789 
790 int
791 setvarcmd(int argc, char **argv)
792 {
793 	if (argc <= 2)
794 		return unsetcmd(argc, argv);
795 	else if (argc == 3)
796 		setvar(argv[1], argv[2], 0);
797 	else
798 		error("too many arguments");
799 	return 0;
800 }
801 
802 
803 /*
804  * The unset builtin command.
805  */
806 
807 int
808 unsetcmd(int argc __unused, char **argv __unused)
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("vf")) != '\0') {
817 		if (i == 'f')
818 			flg_func = 1;
819 		else
820 			flg_var = 1;
821 	}
822 	if (flg_func == 0 && flg_var == 0)
823 		flg_var = 1;
824 
825 	for (ap = argptr; *ap ; ap++) {
826 		if (flg_func)
827 			ret |= unsetfunc(*ap);
828 		if (flg_var)
829 			ret |= unsetvar(*ap);
830 	}
831 	return ret;
832 }
833 
834 
835 /*
836  * Unset the specified variable.
837  */
838 
839 int
840 unsetvar(const char *s)
841 {
842 	struct var **vpp;
843 	struct var *vp;
844 
845 	vp = find_var(s, &vpp, NULL);
846 	if (vp == NULL)
847 		return (0);
848 	if (vp->flags & VREADONLY)
849 		return (1);
850 	INTOFF;
851 	if (vp->text[vp->name_len + 1] != '\0')
852 		setvar(s, nullstr, 0);
853 	if ((vp->flags & VEXPORT) && localevar(vp->text)) {
854 		change_env(__DECONST(char *, s), 0);
855 		setlocale(LC_ALL, "");
856 		updatecharset();
857 	}
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 	INTON;
867 	return (0);
868 }
869 
870 
871 
872 /*
873  * Returns true if the two strings specify the same variable.  The first
874  * variable name is terminated by '='; the second may be terminated by
875  * either '=' or '\0'.
876  */
877 
878 static int
879 varequal(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 characters in 'name'
895  */
896 
897 static struct var *
898 find_var(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 = p - name;
909 
910 	if (lenp)
911 		*lenp = len;
912 	vpp = &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 }
927