xref: /freebsd/bin/sh/var.c (revision 145992504973bd16cf3518af9ba5ce185fefa82a) 
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  * 4. 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 
33 #ifndef lint
34 #if 0
35 static char sccsid[] = "@(#)var.c	8.3 (Berkeley) 5/4/95";
36 #endif
37 #endif /* not lint */
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40 
41 #include <unistd.h>
42 #include <stdlib.h>
43 #include <paths.h>
44 
45 /*
46  * Shell variables.
47  */
48 
49 #include <locale.h>
50 #include <langinfo.h>
51 
52 #include "shell.h"
53 #include "output.h"
54 #include "expand.h"
55 #include "nodes.h"	/* for other headers */
56 #include "eval.h"	/* defines cmdenviron */
57 #include "exec.h"
58 #include "syntax.h"
59 #include "options.h"
60 #include "mail.h"
61 #include "var.h"
62 #include "memalloc.h"
63 #include "error.h"
64 #include "mystring.h"
65 #include "parser.h"
66 #include "builtins.h"
67 #ifndef NO_HISTORY
68 #include "myhistedit.h"
69 #endif
70 
71 
72 #define VTABSIZE 39
73 
74 
75 struct varinit {
76 	struct var *var;
77 	int flags;
78 	const char *text;
79 	void (*func)(const char *);
80 };
81 
82 
83 #ifndef NO_HISTORY
84 struct var vhistsize;
85 struct var vterm;
86 #endif
87 struct var vifs;
88 struct var vmail;
89 struct var vmpath;
90 struct var vpath;
91 struct var vppid;
92 struct var vps1;
93 struct var vps2;
94 struct var vps4;
95 struct var vvers;
96 static struct var voptind;
97 struct var vdisvfork;
98 
99 int forcelocal;
100 
101 static const struct varinit varinit[] = {
102 #ifndef NO_HISTORY
103 	{ &vhistsize,	VUNSET,				"HISTSIZE=",
104 	  sethistsize },
105 #endif
106 	{ &vifs,	0,				"IFS= \t\n",
107 	  NULL },
108 	{ &vmail,	VUNSET,				"MAIL=",
109 	  NULL },
110 	{ &vmpath,	VUNSET,				"MAILPATH=",
111 	  NULL },
112 	{ &vpath,	0,				"PATH=" _PATH_DEFPATH,
113 	  changepath },
114 	{ &vppid,	VUNSET,				"PPID=",
115 	  NULL },
116 	/*
117 	 * vps1 depends on uid
118 	 */
119 	{ &vps2,	0,				"PS2=> ",
120 	  NULL },
121 	{ &vps4,	0,				"PS4=+ ",
122 	  NULL },
123 #ifndef NO_HISTORY
124 	{ &vterm,	VUNSET,				"TERM=",
125 	  setterm },
126 #endif
127 	{ &voptind,	0,				"OPTIND=1",
128 	  getoptsreset },
129 	{ &vdisvfork,	VUNSET,				"SH_DISABLE_VFORK=",
130 	  NULL },
131 	{ NULL,	0,				NULL,
132 	  NULL }
133 };
134 
135 static struct var *vartab[VTABSIZE];
136 
137 static const char *const locale_names[7] = {
138 	"LC_COLLATE", "LC_CTYPE", "LC_MONETARY",
139 	"LC_NUMERIC", "LC_TIME", "LC_MESSAGES", NULL
140 };
141 static const int locale_categories[7] = {
142 	LC_COLLATE, LC_CTYPE, LC_MONETARY, LC_NUMERIC, LC_TIME, LC_MESSAGES, 0
143 };
144 
145 static int varequal(const char *, const char *);
146 static struct var *find_var(const char *, struct var ***, int *);
147 static int localevar(const char *);
148 
149 /*
150  * Initialize the variable symbol tables and import the environment.
151  */
152 
153 #ifdef mkinit
154 INCLUDE "var.h"
155 MKINIT char **environ;
156 INIT {
157 	char **envp;
158 
159 	initvar();
160 	for (envp = environ ; *envp ; envp++) {
161 		if (strchr(*envp, '=')) {
162 			setvareq(*envp, VEXPORT|VTEXTFIXED);
163 		}
164 	}
165 }
166 #endif
167 
168 
169 /*
170  * This routine initializes the builtin variables.  It is called when the
171  * shell is initialized.
172  */
173 
174 void
175 initvar(void)
176 {
177 	char ppid[20];
178 	const struct varinit *ip;
179 	struct var *vp;
180 	struct var **vpp;
181 
182 	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
183 		if (find_var(ip->text, &vpp, &vp->name_len) != NULL)
184 			continue;
185 		vp->next = *vpp;
186 		*vpp = vp;
187 		vp->text = __DECONST(char *, ip->text);
188 		vp->flags = ip->flags | VSTRFIXED | VTEXTFIXED;
189 		vp->func = ip->func;
190 	}
191 	/*
192 	 * PS1 depends on uid
193 	 */
194 	if (find_var("PS1", &vpp, &vps1.name_len) == NULL) {
195 		vps1.next = *vpp;
196 		*vpp = &vps1;
197 		vps1.text = __DECONST(char *, geteuid() ? "PS1=$ " : "PS1=# ");
198 		vps1.flags = VSTRFIXED|VTEXTFIXED;
199 	}
200 	if ((vppid.flags & VEXPORT) == 0) {
201 		fmtstr(ppid, sizeof(ppid), "%d", (int)getppid());
202 		setvarsafe("PPID", ppid, 0);
203 	}
204 }
205 
206 /*
207  * Safe version of setvar, returns 1 on success 0 on failure.
208  */
209 
210 int
211 setvarsafe(const char *name, const char *val, int flags)
212 {
213 	struct jmploc jmploc;
214 	struct jmploc *const savehandler = handler;
215 	int err = 0;
216 	int inton;
217 
218 	inton = is_int_on();
219 	if (setjmp(jmploc.loc))
220 		err = 1;
221 	else {
222 		handler = &jmploc;
223 		setvar(name, val, flags);
224 	}
225 	handler = savehandler;
226 	SETINTON(inton);
227 	return err;
228 }
229 
230 /*
231  * Set the value of a variable.  The flags argument is stored with the
232  * flags of the variable.  If val is NULL, the variable is unset.
233  */
234 
235 void
236 setvar(const char *name, const char *val, int flags)
237 {
238 	const char *p;
239 	int len;
240 	int namelen;
241 	char *nameeq;
242 	int isbad;
243 
244 	isbad = 0;
245 	p = name;
246 	if (! is_name(*p))
247 		isbad = 1;
248 	p++;
249 	for (;;) {
250 		if (! is_in_name(*p)) {
251 			if (*p == '\0' || *p == '=')
252 				break;
253 			isbad = 1;
254 		}
255 		p++;
256 	}
257 	namelen = p - name;
258 	if (isbad)
259 		error("%.*s: bad variable name", namelen, name);
260 	len = namelen + 2;		/* 2 is space for '=' and '\0' */
261 	if (val == NULL) {
262 		flags |= VUNSET;
263 	} else {
264 		len += strlen(val);
265 	}
266 	nameeq = ckmalloc(len);
267 	memcpy(nameeq, name, namelen);
268 	nameeq[namelen] = '=';
269 	if (val)
270 		scopy(val, nameeq + namelen + 1);
271 	else
272 		nameeq[namelen + 1] = '\0';
273 	setvareq(nameeq, flags);
274 }
275 
276 static int
277 localevar(const char *s)
278 {
279 	const char *const *ss;
280 
281 	if (*s != 'L')
282 		return 0;
283 	if (varequal(s + 1, "ANG"))
284 		return 1;
285 	if (strncmp(s + 1, "C_", 2) != 0)
286 		return 0;
287 	if (varequal(s + 3, "ALL"))
288 		return 1;
289 	for (ss = locale_names; *ss ; ss++)
290 		if (varequal(s + 3, *ss + 3))
291 			return 1;
292 	return 0;
293 }
294 
295 
296 /*
297  * Sets/unsets an environment variable from a pointer that may actually be a
298  * pointer into environ where the string should not be manipulated.
299  */
300 static void
301 change_env(const char *s, int set)
302 {
303 	char *eqp;
304 	char *ss;
305 
306 	ss = savestr(s);
307 	if ((eqp = strchr(ss, '=')) != NULL)
308 		*eqp = '\0';
309 	if (set && eqp != NULL)
310 		(void) setenv(ss, eqp + 1, 1);
311 	else
312 		(void) unsetenv(ss);
313 	ckfree(ss);
314 
315 	return;
316 }
317 
318 
319 /*
320  * Same as setvar except that the variable and value are passed in
321  * the first argument as name=value.  Since the first argument will
322  * be actually stored in the table, it should not be a string that
323  * will go away.
324  */
325 
326 void
327 setvareq(char *s, int flags)
328 {
329 	struct var *vp, **vpp;
330 	int nlen;
331 
332 	if (aflag)
333 		flags |= VEXPORT;
334 	if (forcelocal && !(flags & (VNOSET | VNOLOCAL)))
335 		mklocal(s);
336 	vp = find_var(s, &vpp, &nlen);
337 	if (vp != NULL) {
338 		if (vp->flags & VREADONLY)
339 			error("%.*s: is read only", vp->name_len, s);
340 		if (flags & VNOSET)
341 			return;
342 		INTOFF;
343 
344 		if (vp->func && (flags & VNOFUNC) == 0)
345 			(*vp->func)(s + vp->name_len + 1);
346 
347 		if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
348 			ckfree(vp->text);
349 
350 		vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
351 		vp->flags |= flags;
352 		vp->text = s;
353 
354 		/*
355 		 * We could roll this to a function, to handle it as
356 		 * a regular variable function callback, but why bother?
357 		 *
358 		 * Note: this assumes iflag is not set to 1 initially.
359 		 * As part of init(), this is called before arguments
360 		 * are looked at.
361 		 */
362 		if ((vp == &vmpath || (vp == &vmail && ! mpathset())) &&
363 		    iflag == 1)
364 			chkmail(1);
365 		if ((vp->flags & VEXPORT) && localevar(s)) {
366 			change_env(s, 1);
367 			(void) setlocale(LC_ALL, "");
368 			updatecharset();
369 		}
370 		INTON;
371 		return;
372 	}
373 	/* not found */
374 	if (flags & VNOSET)
375 		return;
376 	vp = ckmalloc(sizeof (*vp));
377 	vp->flags = flags;
378 	vp->text = s;
379 	vp->name_len = nlen;
380 	vp->next = *vpp;
381 	vp->func = NULL;
382 	INTOFF;
383 	*vpp = vp;
384 	if ((vp->flags & VEXPORT) && localevar(s)) {
385 		change_env(s, 1);
386 		(void) setlocale(LC_ALL, "");
387 		updatecharset();
388 	}
389 	INTON;
390 }
391 
392 
393 
394 /*
395  * Process a linked list of variable assignments.
396  */
397 
398 void
399 listsetvar(struct strlist *list, int flags)
400 {
401 	struct strlist *lp;
402 
403 	INTOFF;
404 	for (lp = list ; lp ; lp = lp->next) {
405 		setvareq(savestr(lp->text), flags);
406 	}
407 	INTON;
408 }
409 
410 
411 
412 /*
413  * Find the value of a variable.  Returns NULL if not set.
414  */
415 
416 char *
417 lookupvar(const char *name)
418 {
419 	struct var *v;
420 
421 	v = find_var(name, NULL, NULL);
422 	if (v == NULL || v->flags & VUNSET)
423 		return NULL;
424 	return v->text + v->name_len + 1;
425 }
426 
427 
428 
429 /*
430  * Search the environment of a builtin command.  If the second argument
431  * is nonzero, return the value of a variable even if it hasn't been
432  * exported.
433  */
434 
435 char *
436 bltinlookup(const char *name, int doall)
437 {
438 	struct strlist *sp;
439 	struct var *v;
440 	char *result;
441 
442 	result = NULL;
443 	for (sp = cmdenviron ; sp ; sp = sp->next) {
444 		if (varequal(sp->text, name))
445 			result = strchr(sp->text, '=') + 1;
446 	}
447 	if (result != NULL)
448 		return result;
449 
450 	v = find_var(name, NULL, NULL);
451 	if (v == NULL || v->flags & VUNSET ||
452 	    (!doall && (v->flags & VEXPORT) == 0))
453 		return NULL;
454 	return v->text + v->name_len + 1;
455 }
456 
457 
458 /*
459  * Set up locale for a builtin (LANG/LC_* assignments).
460  */
461 void
462 bltinsetlocale(void)
463 {
464 	struct strlist *lp;
465 	int act = 0;
466 	char *loc, *locdef;
467 	int i;
468 
469 	for (lp = cmdenviron ; lp ; lp = lp->next) {
470 		if (localevar(lp->text)) {
471 			act = 1;
472 			break;
473 		}
474 	}
475 	if (!act)
476 		return;
477 	loc = bltinlookup("LC_ALL", 0);
478 	INTOFF;
479 	if (loc != NULL) {
480 		setlocale(LC_ALL, loc);
481 		INTON;
482 		updatecharset();
483 		return;
484 	}
485 	locdef = bltinlookup("LANG", 0);
486 	for (i = 0; locale_names[i] != NULL; i++) {
487 		loc = bltinlookup(locale_names[i], 0);
488 		if (loc == NULL)
489 			loc = locdef;
490 		if (loc != NULL)
491 			setlocale(locale_categories[i], loc);
492 	}
493 	INTON;
494 	updatecharset();
495 }
496 
497 /*
498  * Undo the effect of bltinlocaleset().
499  */
500 void
501 bltinunsetlocale(void)
502 {
503 	struct strlist *lp;
504 
505 	INTOFF;
506 	for (lp = cmdenviron ; lp ; lp = lp->next) {
507 		if (localevar(lp->text)) {
508 			setlocale(LC_ALL, "");
509 			updatecharset();
510 			return;
511 		}
512 	}
513 	INTON;
514 }
515 
516 /*
517  * Update the localeisutf8 flag.
518  */
519 void
520 updatecharset(void)
521 {
522 	char *charset;
523 
524 	charset = nl_langinfo(CODESET);
525 	localeisutf8 = !strcmp(charset, "UTF-8");
526 }
527 
528 void
529 initcharset(void)
530 {
531 	updatecharset();
532 	initial_localeisutf8 = localeisutf8;
533 }
534 
535 /*
536  * Generate a list of exported variables.  This routine is used to construct
537  * the third argument to execve when executing a program.
538  */
539 
540 char **
541 environment(void)
542 {
543 	int nenv;
544 	struct var **vpp;
545 	struct var *vp;
546 	char **env, **ep;
547 
548 	nenv = 0;
549 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
550 		for (vp = *vpp ; vp ; vp = vp->next)
551 			if (vp->flags & VEXPORT)
552 				nenv++;
553 	}
554 	ep = env = stalloc((nenv + 1) * sizeof *env);
555 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
556 		for (vp = *vpp ; vp ; vp = vp->next)
557 			if (vp->flags & VEXPORT)
558 				*ep++ = vp->text;
559 	}
560 	*ep = NULL;
561 	return env;
562 }
563 
564 
565 static int
566 var_compare(const void *a, const void *b)
567 {
568 	const char *const *sa, *const *sb;
569 
570 	sa = a;
571 	sb = b;
572 	/*
573 	 * This compares two var=value strings which creates a different
574 	 * order from what you would probably expect.  POSIX is somewhat
575 	 * ambiguous on what should be sorted exactly.
576 	 */
577 	return strcoll(*sa, *sb);
578 }
579 
580 
581 /*
582  * Command to list all variables which are set.  This is invoked from the
583  * set command when it is called without any options or operands.
584  */
585 
586 int
587 showvarscmd(int argc __unused, char **argv __unused)
588 {
589 	struct var **vpp;
590 	struct var *vp;
591 	const char *s;
592 	const char **vars;
593 	int i, n;
594 
595 	/*
596 	 * POSIX requires us to sort the variables.
597 	 */
598 	n = 0;
599 	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
600 		for (vp = *vpp; vp; vp = vp->next) {
601 			if (!(vp->flags & VUNSET))
602 				n++;
603 		}
604 	}
605 
606 	INTOFF;
607 	vars = ckmalloc(n * sizeof(*vars));
608 	i = 0;
609 	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
610 		for (vp = *vpp; vp; vp = vp->next) {
611 			if (!(vp->flags & VUNSET))
612 				vars[i++] = vp->text;
613 		}
614 	}
615 
616 	qsort(vars, n, sizeof(*vars), var_compare);
617 	for (i = 0; i < n; i++) {
618 		/*
619 		 * Skip improper variable names so the output remains usable as
620 		 * shell input.
621 		 */
622 		if (!isassignment(vars[i]))
623 			continue;
624 		s = strchr(vars[i], '=');
625 		s++;
626 		outbin(vars[i], s - vars[i], out1);
627 		out1qstr(s);
628 		out1c('\n');
629 	}
630 	ckfree(vars);
631 	INTON;
632 
633 	return 0;
634 }
635 
636 
637 
638 /*
639  * The export and readonly commands.
640  */
641 
642 int
643 exportcmd(int argc __unused, char **argv)
644 {
645 	struct var **vpp;
646 	struct var *vp;
647 	char **ap;
648 	char *name;
649 	char *p;
650 	char *cmdname;
651 	int ch, values;
652 	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
653 
654 	cmdname = argv[0];
655 	values = 0;
656 	while ((ch = nextopt("p")) != '\0') {
657 		switch (ch) {
658 		case 'p':
659 			values = 1;
660 			break;
661 		}
662 	}
663 
664 	if (values && *argptr != NULL)
665 		error("-p requires no arguments");
666 	if (*argptr != NULL) {
667 		for (ap = argptr; (name = *ap) != NULL; ap++) {
668 			if ((p = strchr(name, '=')) != NULL) {
669 				p++;
670 			} else {
671 				vp = find_var(name, NULL, NULL);
672 				if (vp != NULL) {
673 					vp->flags |= flag;
674 					if ((vp->flags & VEXPORT) && localevar(vp->text)) {
675 						change_env(vp->text, 1);
676 						(void) setlocale(LC_ALL, "");
677 						updatecharset();
678 					}
679 					continue;
680 				}
681 			}
682 			setvar(name, p, flag);
683 		}
684 	} else {
685 		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
686 			for (vp = *vpp ; vp ; vp = vp->next) {
687 				if (vp->flags & flag) {
688 					if (values) {
689 						/*
690 						 * Skip improper variable names
691 						 * so the output remains usable
692 						 * as shell input.
693 						 */
694 						if (!isassignment(vp->text))
695 							continue;
696 						out1str(cmdname);
697 						out1c(' ');
698 					}
699 					if (values && !(vp->flags & VUNSET)) {
700 						outbin(vp->text,
701 						    vp->name_len + 1, out1);
702 						out1qstr(vp->text +
703 						    vp->name_len + 1);
704 					} else
705 						outbin(vp->text, vp->name_len,
706 						    out1);
707 					out1c('\n');
708 				}
709 			}
710 		}
711 	}
712 	return 0;
713 }
714 
715 
716 /*
717  * The "local" command.
718  */
719 
720 int
721 localcmd(int argc __unused, char **argv __unused)
722 {
723 	char *name;
724 
725 	if (! in_function())
726 		error("Not in a function");
727 	while ((name = *argptr++) != NULL) {
728 		mklocal(name);
729 	}
730 	return 0;
731 }
732 
733 
734 /*
735  * Make a variable a local variable.  When a variable is made local, it's
736  * value and flags are saved in a localvar structure.  The saved values
737  * will be restored when the shell function returns.  We handle the name
738  * "-" as a special case.
739  */
740 
741 void
742 mklocal(char *name)
743 {
744 	struct localvar *lvp;
745 	struct var **vpp;
746 	struct var *vp;
747 
748 	INTOFF;
749 	lvp = ckmalloc(sizeof (struct localvar));
750 	if (name[0] == '-' && name[1] == '\0') {
751 		lvp->text = ckmalloc(sizeof optlist);
752 		memcpy(lvp->text, optlist, sizeof optlist);
753 		vp = NULL;
754 	} else {
755 		vp = find_var(name, &vpp, NULL);
756 		if (vp == NULL) {
757 			if (strchr(name, '='))
758 				setvareq(savestr(name), VSTRFIXED | VNOLOCAL);
759 			else
760 				setvar(name, NULL, VSTRFIXED | VNOLOCAL);
761 			vp = *vpp;	/* the new variable */
762 			lvp->text = NULL;
763 			lvp->flags = VUNSET;
764 		} else {
765 			lvp->text = vp->text;
766 			lvp->flags = vp->flags;
767 			vp->flags |= VSTRFIXED|VTEXTFIXED;
768 			if (name[vp->name_len] == '=')
769 				setvareq(savestr(name), VNOLOCAL);
770 		}
771 	}
772 	lvp->vp = vp;
773 	lvp->next = localvars;
774 	localvars = lvp;
775 	INTON;
776 }
777 
778 
779 /*
780  * Called after a function returns.
781  */
782 
783 void
784 poplocalvars(void)
785 {
786 	struct localvar *lvp;
787 	struct var *vp;
788 
789 	while ((lvp = localvars) != NULL) {
790 		localvars = lvp->next;
791 		vp = lvp->vp;
792 		if (vp == NULL) {	/* $- saved */
793 			memcpy(optlist, lvp->text, sizeof optlist);
794 			ckfree(lvp->text);
795 			optschanged();
796 		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
797 			(void)unsetvar(vp->text);
798 		} else {
799 			if ((vp->flags & VTEXTFIXED) == 0)
800 				ckfree(vp->text);
801 			vp->flags = lvp->flags;
802 			vp->text = lvp->text;
803 		}
804 		ckfree(lvp);
805 	}
806 }
807 
808 
809 int
810 setvarcmd(int argc, char **argv)
811 {
812 	if (argc <= 2)
813 		return unsetcmd(argc, argv);
814 	else if (argc == 3)
815 		setvar(argv[1], argv[2], 0);
816 	else
817 		error("too many arguments");
818 	return 0;
819 }
820 
821 
822 /*
823  * The unset builtin command.
824  */
825 
826 int
827 unsetcmd(int argc __unused, char **argv __unused)
828 {
829 	char **ap;
830 	int i;
831 	int flg_func = 0;
832 	int flg_var = 0;
833 	int ret = 0;
834 
835 	while ((i = nextopt("vf")) != '\0') {
836 		if (i == 'f')
837 			flg_func = 1;
838 		else
839 			flg_var = 1;
840 	}
841 	if (flg_func == 0 && flg_var == 0)
842 		flg_var = 1;
843 
844 	for (ap = argptr; *ap ; ap++) {
845 		if (flg_func)
846 			ret |= unsetfunc(*ap);
847 		if (flg_var)
848 			ret |= unsetvar(*ap);
849 	}
850 	return ret;
851 }
852 
853 
854 /*
855  * Unset the specified variable.
856  */
857 
858 int
859 unsetvar(const char *s)
860 {
861 	struct var **vpp;
862 	struct var *vp;
863 
864 	vp = find_var(s, &vpp, NULL);
865 	if (vp == NULL)
866 		return (0);
867 	if (vp->flags & VREADONLY)
868 		return (1);
869 	INTOFF;
870 	if (vp->text[vp->name_len + 1] != '\0')
871 		setvar(s, nullstr, 0);
872 	if ((vp->flags & VEXPORT) && localevar(vp->text)) {
873 		change_env(s, 0);
874 		setlocale(LC_ALL, "");
875 		updatecharset();
876 	}
877 	vp->flags &= ~VEXPORT;
878 	vp->flags |= VUNSET;
879 	if ((vp->flags & VSTRFIXED) == 0) {
880 		if ((vp->flags & VTEXTFIXED) == 0)
881 			ckfree(vp->text);
882 		*vpp = vp->next;
883 		ckfree(vp);
884 	}
885 	INTON;
886 	return (0);
887 }
888 
889 
890 
891 /*
892  * Returns true if the two strings specify the same varable.  The first
893  * variable name is terminated by '='; the second may be terminated by
894  * either '=' or '\0'.
895  */
896 
897 static int
898 varequal(const char *p, const char *q)
899 {
900 	while (*p == *q++) {
901 		if (*p++ == '=')
902 			return 1;
903 	}
904 	if (*p == '=' && *(q - 1) == '\0')
905 		return 1;
906 	return 0;
907 }
908 
909 /*
910  * Search for a variable.
911  * 'name' may be terminated by '=' or a NUL.
912  * vppp is set to the pointer to vp, or the list head if vp isn't found
913  * lenp is set to the number of charactets in 'name'
914  */
915 
916 static struct var *
917 find_var(const char *name, struct var ***vppp, int *lenp)
918 {
919 	unsigned int hashval;
920 	int len;
921 	struct var *vp, **vpp;
922 	const char *p = name;
923 
924 	hashval = 0;
925 	while (*p && *p != '=')
926 		hashval = 2 * hashval + (unsigned char)*p++;
927 	len = p - name;
928 
929 	if (lenp)
930 		*lenp = len;
931 	vpp = &vartab[hashval % VTABSIZE];
932 	if (vppp)
933 		*vppp = vpp;
934 
935 	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
936 		if (vp->name_len != len)
937 			continue;
938 		if (memcmp(vp->text, name, len) != 0)
939 			continue;
940 		if (vppp)
941 			*vppp = vpp;
942 		return vp;
943 	}
944 	return NULL;
945 }
946