xref: /dragonfly/bin/sh/var.c (revision a563ca70) 
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 1.63 2011/06/17 10:21:24 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 #include "builtins.h"
66 #ifndef NO_HISTORY
67 #include "myhistedit.h"
68 #endif
69 
70 
71 #define VTABSIZE 39
72 
73 
74 struct varinit {
75 	struct var *var;
76 	int flags;
77 	const char *text;
78 	void (*func)(const char *);
79 };
80 
81 
82 #ifndef NO_HISTORY
83 struct var vhistsize;
84 struct var vterm;
85 #endif
86 struct var vifs;
87 struct var vmail;
88 struct var vmpath;
89 struct var vpath;
90 struct var vppid;
91 struct var vps1;
92 struct var vps2;
93 struct var vps4;
94 struct var vvers;
95 static struct var voptind;
96 
97 int forcelocal;
98 
99 static const struct varinit varinit[] = {
100 #ifndef NO_HISTORY
101 	{ &vhistsize,	VUNSET,				"HISTSIZE=",
102 	  sethistsize },
103 #endif
104 	{ &vifs,	0,				"IFS= \t\n",
105 	  NULL },
106 	{ &vmail,	VUNSET,				"MAIL=",
107 	  NULL },
108 	{ &vmpath,	VUNSET,				"MAILPATH=",
109 	  NULL },
110 	{ &vpath,	0,				"PATH=" _PATH_DEFPATH,
111 	  changepath },
112 	{ &vppid,	VUNSET,				"PPID=",
113 	  NULL },
114 	/*
115 	 * vps1 depends on uid
116 	 */
117 	{ &vps2,	0,				"PS2=> ",
118 	  NULL },
119 	{ &vps4,	0,				"PS4=+ ",
120 	  NULL },
121 #ifndef NO_HISTORY
122 	{ &vterm,	VUNSET,				"TERM=",
123 	  setterm },
124 #endif
125 	{ &voptind,	0,				"OPTIND=1",
126 	  getoptsreset },
127 	{ NULL,	0,				NULL,
128 	  NULL }
129 };
130 
131 static struct var *vartab[VTABSIZE];
132 
133 static const char *const locale_names[7] = {
134 	"LC_COLLATE", "LC_CTYPE", "LC_MONETARY",
135 	"LC_NUMERIC", "LC_TIME", "LC_MESSAGES", NULL
136 };
137 static const int locale_categories[7] = {
138 	LC_COLLATE, LC_CTYPE, LC_MONETARY, LC_NUMERIC, LC_TIME, LC_MESSAGES, 0
139 };
140 
141 static int varequal(const char *, const char *);
142 static struct var *find_var(const char *, struct var ***, int *);
143 static int localevar(const char *);
144 
145 /*
146  * Initialize the variable symbol tables and import the environment.
147  */
148 
149 #ifdef mkinit
150 INCLUDE "var.h"
151 MKINIT char **environ;
152 INIT {
153 	char **envp;
154 
155 	initvar();
156 	for (envp = environ ; *envp ; envp++) {
157 		if (strchr(*envp, '=')) {
158 			setvareq(*envp, VEXPORT|VTEXTFIXED);
159 		}
160 	}
161 }
162 #endif
163 
164 
165 /*
166  * This routine initializes the builtin variables.  It is called when the
167  * shell is initialized.
168  */
169 
170 void
171 initvar(void)
172 {
173 	char ppid[20];
174 	const struct varinit *ip;
175 	struct var *vp;
176 	struct var **vpp;
177 
178 	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
179 		if (find_var(ip->text, &vpp, &vp->name_len) != NULL)
180 			continue;
181 		vp->next = *vpp;
182 		*vpp = vp;
183 		vp->text = __DECONST(char *, ip->text);
184 		vp->flags = ip->flags | VSTRFIXED | VTEXTFIXED;
185 		vp->func = ip->func;
186 	}
187 	/*
188 	 * PS1 depends on uid
189 	 */
190 	if (find_var("PS1", &vpp, &vps1.name_len) == NULL) {
191 		vps1.next = *vpp;
192 		*vpp = &vps1;
193 		vps1.text = __DECONST(char *, geteuid() ? "PS1=$ " : "PS1=# ");
194 		vps1.flags = VSTRFIXED|VTEXTFIXED;
195 	}
196 	if ((vppid.flags & VEXPORT) == 0) {
197 		fmtstr(ppid, sizeof(ppid), "%d", (int)getppid());
198 		setvarsafe("PPID", ppid, 0);
199 	}
200 }
201 
202 /*
203  * Safe version of setvar, returns 1 on success 0 on failure.
204  */
205 
206 int
207 setvarsafe(const char *name, const char *val, int flags)
208 {
209 	struct jmploc jmploc;
210 	struct jmploc *const savehandler = handler;
211 	int err = 0;
212 	int inton;
213 
214 	inton = is_int_on();
215 	if (setjmp(jmploc.loc))
216 		err = 1;
217 	else {
218 		handler = &jmploc;
219 		setvar(name, val, flags);
220 	}
221 	handler = savehandler;
222 	SETINTON(inton);
223 	return err;
224 }
225 
226 /*
227  * Set the value of a variable.  The flags argument is stored with the
228  * flags of the variable.  If val is NULL, the variable is unset.
229  */
230 
231 void
232 setvar(const char *name, const char *val, int flags)
233 {
234 	const char *p;
235 	int len;
236 	int namelen;
237 	char *nameeq;
238 	int isbad;
239 
240 	isbad = 0;
241 	p = name;
242 	if (!is_name(*p))
243 		isbad = 1;
244 	p++;
245 	for (;;) {
246 		if (!is_in_name(*p)) {
247 			if (*p == '\0' || *p == '=')
248 				break;
249 			isbad = 1;
250 		}
251 		p++;
252 	}
253 	namelen = p - name;
254 	if (isbad)
255 		error("%.*s: bad variable name", namelen, name);
256 	len = namelen + 2;		/* 2 is space for '=' and '\0' */
257 	if (val == NULL) {
258 		flags |= VUNSET;
259 	} else {
260 		len += strlen(val);
261 	}
262 	nameeq = ckmalloc(len);
263 	memcpy(nameeq, name, namelen);
264 	nameeq[namelen] = '=';
265 	if (val)
266 		scopy(val, nameeq + namelen + 1);
267 	else
268 		nameeq[namelen + 1] = '\0';
269 	setvareq(nameeq, flags);
270 }
271 
272 static int
273 localevar(const char *s)
274 {
275 	const char *const *ss;
276 
277 	if (*s != 'L')
278 		return 0;
279 	if (varequal(s + 1, "ANG"))
280 		return 1;
281 	if (strncmp(s + 1, "C_", 2) != 0)
282 		return 0;
283 	if (varequal(s + 3, "ALL"))
284 		return 1;
285 	for (ss = locale_names; *ss ; ss++)
286 		if (varequal(s + 3, *ss + 3))
287 			return 1;
288 	return 0;
289 }
290 
291 /*
292  * Sets/unsets an environment variable from a pointer that may actually be a
293  * pointer into environ where the string should not be manipulated.
294  */
295 static void
296 change_env(const char *s, int set)
297 {
298 	char *eqp;
299 	char *ss;
300 
301 	ss = savestr(s);
302 	if ((eqp = strchr(ss, '=')) != NULL)
303 		*eqp = '\0';
304 	if (set && eqp != NULL) {
305 		if (setenv(ss, eqp + 1, 1) != 0)
306 			error("setenv: cannot set %s=%s", ss, eqp + 1);
307 	} else
308 		unsetenv(ss);
309 	ckfree(ss);
310 }
311 
312 
313 /*
314  * Same as setvar except that the variable and value are passed in
315  * the first argument as name=value.  Since the first argument will
316  * be actually stored in the table, it should not be a string that
317  * will go away.
318  */
319 
320 void
321 setvareq(char *s, int flags)
322 {
323 	struct var *vp, **vpp;
324 	int nlen;
325 
326 	if (aflag)
327 		flags |= VEXPORT;
328 	if (forcelocal && !(flags & (VNOSET | VNOLOCAL)))
329 		mklocal(s);
330 	vp = find_var(s, &vpp, &nlen);
331 	if (vp != NULL) {
332 		if (vp->flags & VREADONLY)
333 			error("%.*s: is read only", vp->name_len, s);
334 		if (flags & VNOSET)
335 			return;
336 		INTOFF;
337 
338 		if (vp->func && (flags & VNOFUNC) == 0)
339 			(*vp->func)(s + vp->name_len + 1);
340 
341 		if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
342 			ckfree(vp->text);
343 
344 		vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
345 		vp->flags |= flags;
346 		vp->text = s;
347 
348 		/*
349 		 * We could roll this to a function, to handle it as
350 		 * a regular variable function callback, but why bother?
351 		 *
352 		 * Note: this assumes iflag is not set to 1 initially.
353 		 * As part of init(), this is called before arguments
354 		 * are looked at.
355 		 */
356 		if ((vp == &vmpath || (vp == &vmail && ! mpathset())) &&
357 		    iflag == 1)
358 			chkmail(1);
359 		if ((vp->flags & VEXPORT) && localevar(s)) {
360 			change_env(s, 1);
361 			setlocale(LC_ALL, "");
362 			updatecharset();
363 		}
364 		INTON;
365 		return;
366 	}
367 	/* not found */
368 	if (flags & VNOSET)
369 		return;
370 	vp = ckmalloc(sizeof (*vp));
371 	vp->flags = flags;
372 	vp->text = s;
373 	vp->name_len = nlen;
374 	vp->next = *vpp;
375 	vp->func = NULL;
376 	INTOFF;
377 	*vpp = vp;
378 	if ((vp->flags & VEXPORT) && localevar(s)) {
379 		change_env(s, 1);
380 		setlocale(LC_ALL, "");
381 		updatecharset();
382 	}
383 	INTON;
384 }
385 
386 
387 
388 /*
389  * Process a linked list of variable assignments.
390  */
391 
392 void
393 listsetvar(struct strlist *list, int flags)
394 {
395 	struct strlist *lp;
396 
397 	INTOFF;
398 	for (lp = list ; lp ; lp = lp->next) {
399 		setvareq(savestr(lp->text), flags);
400 	}
401 	INTON;
402 }
403 
404 
405 
406 /*
407  * Find the value of a variable.  Returns NULL if not set.
408  */
409 
410 char *
411 lookupvar(const char *name)
412 {
413 	struct var *v;
414 
415 	v = find_var(name, NULL, NULL);
416 	if (v == NULL || v->flags & VUNSET)
417 		return NULL;
418 	return v->text + v->name_len + 1;
419 }
420 
421 
422 
423 /*
424  * Search the environment of a builtin command.  If the second argument
425  * is nonzero, return the value of a variable even if it hasn't been
426  * exported.
427  */
428 
429 char *
430 bltinlookup(const char *name, int doall)
431 {
432 	struct strlist *sp;
433 	struct var *v;
434 	char *result;
435 
436 	result = NULL;
437 	for (sp = cmdenviron ; sp ; sp = sp->next) {
438 		if (varequal(sp->text, name))
439 			result = strchr(sp->text, '=') + 1;
440 	}
441 	if (result != NULL)
442 		return result;
443 
444 	v = find_var(name, NULL, NULL);
445 	if (v == NULL || v->flags & VUNSET ||
446 	    (!doall && (v->flags & VEXPORT) == 0))
447 		return NULL;
448 	return v->text + v->name_len + 1;
449 }
450 
451 
452 /*
453  * Set up locale for a builtin (LANG/LC_* assignments).
454  */
455 void
456 bltinsetlocale(void)
457 {
458 	struct strlist *lp;
459 	int act = 0;
460 	char *loc, *locdef;
461 	int i;
462 
463 	for (lp = cmdenviron ; lp ; lp = lp->next) {
464 		if (localevar(lp->text)) {
465 			act = 1;
466 			break;
467 		}
468 	}
469 	if (!act)
470 		return;
471 	loc = bltinlookup("LC_ALL", 0);
472 	INTOFF;
473 	if (loc != NULL) {
474 		setlocale(LC_ALL, loc);
475 		INTON;
476 		updatecharset();
477 		return;
478 	}
479 	locdef = bltinlookup("LANG", 0);
480 	for (i = 0; locale_names[i] != NULL; i++) {
481 		loc = bltinlookup(locale_names[i], 0);
482 		if (loc == NULL)
483 			loc = locdef;
484 		if (loc != NULL)
485 			setlocale(locale_categories[i], loc);
486 	}
487 	INTON;
488 	updatecharset();
489 }
490 
491 /*
492  * Undo the effect of bltinlocaleset().
493  */
494 void
495 bltinunsetlocale(void)
496 {
497 	struct strlist *lp;
498 
499 	INTOFF;
500 	for (lp = cmdenviron ; lp ; lp = lp->next) {
501 		if (localevar(lp->text)) {
502 			setlocale(LC_ALL, "");
503 			updatecharset();
504 			return;
505 		}
506 	}
507 	INTON;
508 }
509 
510 /*
511  * Update the localeisutf8 flag.
512  */
513 void
514 updatecharset(void)
515 {
516 	char *charset;
517 
518 	charset = nl_langinfo(CODESET);
519 	localeisutf8 = !strcmp(charset, "UTF-8");
520 }
521 
522 void
523 initcharset(void)
524 {
525 	updatecharset();
526 	initial_localeisutf8 = localeisutf8;
527 }
528 
529 /*
530  * Generate a list of exported variables.  This routine is used to construct
531  * the third argument to execve when executing a program.
532  */
533 
534 char **
535 environment(void)
536 {
537 	int nenv;
538 	struct var **vpp;
539 	struct var *vp;
540 	char **env, **ep;
541 
542 	nenv = 0;
543 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
544 		for (vp = *vpp ; vp ; vp = vp->next)
545 			if (vp->flags & VEXPORT)
546 				nenv++;
547 	}
548 	ep = env = stalloc((nenv + 1) * sizeof *env);
549 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
550 		for (vp = *vpp ; vp ; vp = vp->next)
551 			if (vp->flags & VEXPORT)
552 				*ep++ = vp->text;
553 	}
554 	*ep = NULL;
555 	return env;
556 }
557 
558 
559 static int
560 var_compare(const void *a, const void *b)
561 {
562 	const char *const *sa, *const *sb;
563 
564 	sa = a;
565 	sb = b;
566 	/*
567 	 * This compares two var=value strings which creates a different
568 	 * order from what you would probably expect.  POSIX is somewhat
569 	 * ambiguous on what should be sorted exactly.
570 	 */
571 	return strcoll(*sa, *sb);
572 }
573 
574 
575 /*
576  * Command to list all variables which are set.  This is invoked from the
577  * set command when it is called without any options or operands.
578  */
579 
580 int
581 showvarscmd(int argc __unused, char **argv __unused)
582 {
583 	struct var **vpp;
584 	struct var *vp;
585 	const char *s;
586 	const char **vars;
587 	int i, n;
588 
589 	/*
590 	 * POSIX requires us to sort the variables.
591 	 */
592 	n = 0;
593 	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
594 		for (vp = *vpp; vp; vp = vp->next) {
595 			if (!(vp->flags & VUNSET))
596 				n++;
597 		}
598 	}
599 
600 	INTON;
601 	vars = ckmalloc(n * sizeof(*vars));
602 	i = 0;
603 	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
604 		for (vp = *vpp; vp; vp = vp->next) {
605 			if (!(vp->flags & VUNSET))
606 				vars[i++] = vp->text;
607 		}
608 	}
609 
610 	qsort(vars, n, sizeof(*vars), var_compare);
611 	for (i = 0; i < n; i++) {
612 		/*
613 		 * Skip improper variable names so the output remains usable as
614 		 * shell input.
615 		 */
616 		if (!isassignment(vars[i]))
617 			continue;
618 		s = strchr(vars[i], '=');
619 		s++;
620 		outbin(vars[i], s - vars[i], out1);
621 		out1qstr(s);
622 		out1c('\n');
623 	}
624 	ckfree(vars);
625 	INTOFF;
626 
627 	return 0;
628 }
629 
630 
631 
632 /*
633  * The export and readonly commands.
634  */
635 
636 int
637 exportcmd(int argc, char **argv)
638 {
639 	struct var **vpp;
640 	struct var *vp;
641 	char *name;
642 	char *p;
643 	char *cmdname;
644 	int ch, values;
645 	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
646 
647 	cmdname = argv[0];
648 	optreset = optind = 1;
649 	opterr = 0;
650 	values = 0;
651 	while ((ch = getopt(argc, argv, "p")) != -1) {
652 		switch (ch) {
653 		case 'p':
654 			values = 1;
655 			break;
656 		case '?':
657 		default:
658 			error("unknown option: -%c", optopt);
659 		}
660 	}
661 	argc -= optind;
662 	argv += optind;
663 
664 	if (values && argc != 0)
665 		error("-p requires no arguments");
666 	if (argc != 0) {
667 		while ((name = *argv++) != NULL) {
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 						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 			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(__DECONST(char *, 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 variable.  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 characters 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