xref: /dragonfly/bin/sh/var.c (revision 20c2db9a) 
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: head/bin/sh/var.c 245689 2013-01-20 12:44:50Z jilles $
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 struct var vdisvfork;
97 
98 int forcelocal;
99 
100 static const struct varinit varinit[] = {
101 #ifndef NO_HISTORY
102 	{ &vhistsize,	VUNSET,				"HISTSIZE=",
103 	  sethistsize },
104 #endif
105 	{ &vifs,	0,				"IFS= \t\n",
106 	  NULL },
107 	{ &vmail,	VUNSET,				"MAIL=",
108 	  NULL },
109 	{ &vmpath,	VUNSET,				"MAILPATH=",
110 	  NULL },
111 	{ &vpath,	0,				"PATH=" _PATH_DEFPATH,
112 	  changepath },
113 	{ &vppid,	VUNSET,				"PPID=",
114 	  NULL },
115 	/*
116 	 * vps1 depends on uid
117 	 */
118 	{ &vps2,	0,				"PS2=> ",
119 	  NULL },
120 	{ &vps4,	0,				"PS4=+ ",
121 	  NULL },
122 #ifndef NO_HISTORY
123 	{ &vterm,	VUNSET,				"TERM=",
124 	  setterm },
125 #endif
126 	{ &voptind,	0,				"OPTIND=1",
127 	  getoptsreset },
128 	{ &vdisvfork,	VUNSET,				"SH_DISABLE_VFORK=",
129 	  NULL },
130 	{ NULL,	0,				NULL,
131 	  NULL }
132 };
133 
134 static struct var *vartab[VTABSIZE];
135 
136 static const char *const locale_names[7] = {
137 	"LC_COLLATE", "LC_CTYPE", "LC_MONETARY",
138 	"LC_NUMERIC", "LC_TIME", "LC_MESSAGES", NULL
139 };
140 static const int locale_categories[7] = {
141 	LC_COLLATE, LC_CTYPE, LC_MONETARY, LC_NUMERIC, LC_TIME, LC_MESSAGES, 0
142 };
143 
144 static int varequal(const char *, const char *);
145 static struct var *find_var(const char *, struct var ***, int *);
146 static int localevar(const char *);
147 
148 extern char **environ;
149 
150 /*
151  * This routine initializes the builtin variables and imports the environment.
152  * It is called when the shell is initialized.
153  */
154 
155 void
156 initvar(void)
157 {
158 	char ppid[20];
159 	const struct varinit *ip;
160 	struct var *vp;
161 	struct var **vpp;
162 	char **envp;
163 
164 	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
165 		if (find_var(ip->text, &vpp, &vp->name_len) != NULL)
166 			continue;
167 		vp->next = *vpp;
168 		*vpp = vp;
169 		vp->text = __DECONST(char *, ip->text);
170 		vp->flags = ip->flags | VSTRFIXED | VTEXTFIXED;
171 		vp->func = ip->func;
172 	}
173 	/*
174 	 * PS1 depends on uid
175 	 */
176 	if (find_var("PS1", &vpp, &vps1.name_len) == NULL) {
177 		vps1.next = *vpp;
178 		*vpp = &vps1;
179 		vps1.text = __DECONST(char *, geteuid() ? "PS1=$ " : "PS1=# ");
180 		vps1.flags = VSTRFIXED|VTEXTFIXED;
181 	}
182 	if ((vppid.flags & VEXPORT) == 0) {
183 		fmtstr(ppid, sizeof(ppid), "%d", (int)getppid());
184 		setvarsafe("PPID", ppid, 0);
185 	}
186 	for (envp = environ ; *envp ; envp++) {
187 		if (strchr(*envp, '=')) {
188 			setvareq(*envp, VEXPORT|VTEXTFIXED);
189 		}
190 	}
191 }
192 
193 /*
194  * Safe version of setvar, returns 1 on success 0 on failure.
195  */
196 
197 int
198 setvarsafe(const char *name, const char *val, int flags)
199 {
200 	struct jmploc jmploc;
201 	struct jmploc *const savehandler = handler;
202 	int err = 0;
203 	int inton;
204 
205 	inton = is_int_on();
206 	if (setjmp(jmploc.loc))
207 		err = 1;
208 	else {
209 		handler = &jmploc;
210 		setvar(name, val, flags);
211 	}
212 	handler = savehandler;
213 	SETINTON(inton);
214 	return err;
215 }
216 
217 /*
218  * Set the value of a variable.  The flags argument is stored with the
219  * flags of the variable.  If val is NULL, the variable is unset.
220  */
221 
222 void
223 setvar(const char *name, const char *val, int flags)
224 {
225 	const char *p;
226 	int len;
227 	int namelen;
228 	char *nameeq;
229 	int isbad;
230 
231 	isbad = 0;
232 	p = name;
233 	if (!is_name(*p))
234 		isbad = 1;
235 	p++;
236 	for (;;) {
237 		if (!is_in_name(*p)) {
238 			if (*p == '\0' || *p == '=')
239 				break;
240 			isbad = 1;
241 		}
242 		p++;
243 	}
244 	namelen = p - name;
245 	if (isbad)
246 		error("%.*s: bad variable name", namelen, name);
247 	len = namelen + 2;		/* 2 is space for '=' and '\0' */
248 	if (val == NULL) {
249 		flags |= VUNSET;
250 	} else {
251 		len += strlen(val);
252 	}
253 	nameeq = ckmalloc(len);
254 	memcpy(nameeq, name, namelen);
255 	nameeq[namelen] = '=';
256 	if (val)
257 		scopy(val, nameeq + namelen + 1);
258 	else
259 		nameeq[namelen + 1] = '\0';
260 	setvareq(nameeq, flags);
261 }
262 
263 static int
264 localevar(const char *s)
265 {
266 	const char *const *ss;
267 
268 	if (*s != 'L')
269 		return 0;
270 	if (varequal(s + 1, "ANG"))
271 		return 1;
272 	if (strncmp(s + 1, "C_", 2) != 0)
273 		return 0;
274 	if (varequal(s + 3, "ALL"))
275 		return 1;
276 	for (ss = locale_names; *ss ; ss++)
277 		if (varequal(s + 3, *ss + 3))
278 			return 1;
279 	return 0;
280 }
281 
282 /*
283  * Sets/unsets an environment variable from a pointer that may actually be a
284  * pointer into environ where the string should not be manipulated.
285  */
286 static void
287 change_env(const char *s, int set)
288 {
289 	char *eqp;
290 	char *ss;
291 
292 	ss = savestr(s);
293 	if ((eqp = strchr(ss, '=')) != NULL)
294 		*eqp = '\0';
295 	if (set && eqp != NULL) {
296 		if (setenv(ss, eqp + 1, 1) != 0)
297 			error("setenv: cannot set %s=%s", ss, eqp + 1);
298 	} else
299 		unsetenv(ss);
300 	ckfree(ss);
301 }
302 
303 
304 /*
305  * Same as setvar except that the variable and value are passed in
306  * the first argument as name=value.  Since the first argument will
307  * be actually stored in the table, it should not be a string that
308  * will go away.
309  */
310 
311 void
312 setvareq(char *s, int flags)
313 {
314 	struct var *vp, **vpp;
315 	int nlen;
316 
317 	if (aflag)
318 		flags |= VEXPORT;
319 	if (forcelocal && !(flags & (VNOSET | VNOLOCAL)))
320 		mklocal(s);
321 	vp = find_var(s, &vpp, &nlen);
322 	if (vp != NULL) {
323 		if (vp->flags & VREADONLY)
324 			error("%.*s: is read only", vp->name_len, s);
325 		if (flags & VNOSET)
326 			return;
327 		INTOFF;
328 
329 		if (vp->func && (flags & VNOFUNC) == 0)
330 			(*vp->func)(s + vp->name_len + 1);
331 
332 		if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
333 			ckfree(vp->text);
334 
335 		vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
336 		vp->flags |= flags;
337 		vp->text = s;
338 
339 		/*
340 		 * We could roll this to a function, to handle it as
341 		 * a regular variable function callback, but why bother?
342 		 *
343 		 * Note: this assumes iflag is not set to 1 initially.
344 		 * As part of initvar(), this is called before arguments
345 		 * are looked at.
346 		 */
347 		if ((vp == &vmpath || (vp == &vmail && ! mpathset())) &&
348 		    iflag == 1)
349 			chkmail(1);
350 		if ((vp->flags & VEXPORT) && localevar(s)) {
351 			change_env(s, 1);
352 			setlocale(LC_ALL, "");
353 			updatecharset();
354 		}
355 		INTON;
356 		return;
357 	}
358 	/* not found */
359 	if (flags & VNOSET)
360 		return;
361 	vp = ckmalloc(sizeof (*vp));
362 	vp->flags = flags;
363 	vp->text = s;
364 	vp->name_len = nlen;
365 	vp->next = *vpp;
366 	vp->func = NULL;
367 	INTOFF;
368 	*vpp = vp;
369 	if ((vp->flags & VEXPORT) && localevar(s)) {
370 		change_env(s, 1);
371 		setlocale(LC_ALL, "");
372 		updatecharset();
373 	}
374 	INTON;
375 }
376 
377 
378 
379 /*
380  * Process a linked list of variable assignments.
381  */
382 
383 void
384 listsetvar(struct strlist *list, int flags)
385 {
386 	struct strlist *lp;
387 
388 	INTOFF;
389 	for (lp = list ; lp ; lp = lp->next) {
390 		setvareq(savestr(lp->text), flags);
391 	}
392 	INTON;
393 }
394 
395 
396 
397 /*
398  * Find the value of a variable.  Returns NULL if not set.
399  */
400 
401 char *
402 lookupvar(const char *name)
403 {
404 	struct var *v;
405 
406 	v = find_var(name, NULL, NULL);
407 	if (v == NULL || v->flags & VUNSET)
408 		return NULL;
409 	return v->text + v->name_len + 1;
410 }
411 
412 
413 
414 /*
415  * Search the environment of a builtin command.  If the second argument
416  * is nonzero, return the value of a variable even if it hasn't been
417  * exported.
418  */
419 
420 char *
421 bltinlookup(const char *name, int doall)
422 {
423 	struct strlist *sp;
424 	struct var *v;
425 	char *result;
426 
427 	result = NULL;
428 	for (sp = cmdenviron ; sp ; sp = sp->next) {
429 		if (varequal(sp->text, name))
430 			result = strchr(sp->text, '=') + 1;
431 	}
432 	if (result != NULL)
433 		return result;
434 
435 	v = find_var(name, NULL, NULL);
436 	if (v == NULL || v->flags & VUNSET ||
437 	    (!doall && (v->flags & VEXPORT) == 0))
438 		return NULL;
439 	return v->text + v->name_len + 1;
440 }
441 
442 
443 /*
444  * Set up locale for a builtin (LANG/LC_* assignments).
445  */
446 void
447 bltinsetlocale(void)
448 {
449 	struct strlist *lp;
450 	int act = 0;
451 	char *loc, *locdef;
452 	int i;
453 
454 	for (lp = cmdenviron ; lp ; lp = lp->next) {
455 		if (localevar(lp->text)) {
456 			act = 1;
457 			break;
458 		}
459 	}
460 	if (!act)
461 		return;
462 	loc = bltinlookup("LC_ALL", 0);
463 	INTOFF;
464 	if (loc != NULL) {
465 		setlocale(LC_ALL, loc);
466 		INTON;
467 		updatecharset();
468 		return;
469 	}
470 	locdef = bltinlookup("LANG", 0);
471 	for (i = 0; locale_names[i] != NULL; i++) {
472 		loc = bltinlookup(locale_names[i], 0);
473 		if (loc == NULL)
474 			loc = locdef;
475 		if (loc != NULL)
476 			setlocale(locale_categories[i], loc);
477 	}
478 	INTON;
479 	updatecharset();
480 }
481 
482 /*
483  * Undo the effect of bltinlocaleset().
484  */
485 void
486 bltinunsetlocale(void)
487 {
488 	struct strlist *lp;
489 
490 	INTOFF;
491 	for (lp = cmdenviron ; lp ; lp = lp->next) {
492 		if (localevar(lp->text)) {
493 			setlocale(LC_ALL, "");
494 			updatecharset();
495 			return;
496 		}
497 	}
498 	INTON;
499 }
500 
501 /*
502  * Update the localeisutf8 flag.
503  */
504 void
505 updatecharset(void)
506 {
507 	char *charset;
508 
509 	charset = nl_langinfo(CODESET);
510 	localeisutf8 = !strcmp(charset, "UTF-8");
511 }
512 
513 void
514 initcharset(void)
515 {
516 	updatecharset();
517 	initial_localeisutf8 = localeisutf8;
518 }
519 
520 /*
521  * Generate a list of exported variables.  This routine is used to construct
522  * the third argument to execve when executing a program.
523  */
524 
525 char **
526 environment(void)
527 {
528 	int nenv;
529 	struct var **vpp;
530 	struct var *vp;
531 	char **env, **ep;
532 
533 	nenv = 0;
534 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
535 		for (vp = *vpp ; vp ; vp = vp->next)
536 			if (vp->flags & VEXPORT)
537 				nenv++;
538 	}
539 	ep = env = stalloc((nenv + 1) * sizeof *env);
540 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
541 		for (vp = *vpp ; vp ; vp = vp->next)
542 			if (vp->flags & VEXPORT)
543 				*ep++ = vp->text;
544 	}
545 	*ep = NULL;
546 	return env;
547 }
548 
549 
550 static int
551 var_compare(const void *a, const void *b)
552 {
553 	const char *const *sa, *const *sb;
554 
555 	sa = a;
556 	sb = b;
557 	/*
558 	 * This compares two var=value strings which creates a different
559 	 * order from what you would probably expect.  POSIX is somewhat
560 	 * ambiguous on what should be sorted exactly.
561 	 */
562 	return strcoll(*sa, *sb);
563 }
564 
565 
566 /*
567  * Command to list all variables which are set.  This is invoked from the
568  * set command when it is called without any options or operands.
569  */
570 
571 int
572 showvarscmd(int argc __unused, char **argv __unused)
573 {
574 	struct var **vpp;
575 	struct var *vp;
576 	const char *s;
577 	const char **vars;
578 	int i, n;
579 
580 	/*
581 	 * POSIX requires us to sort the variables.
582 	 */
583 	n = 0;
584 	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
585 		for (vp = *vpp; vp; vp = vp->next) {
586 			if (!(vp->flags & VUNSET))
587 				n++;
588 		}
589 	}
590 
591 	INTOFF;
592 	vars = ckmalloc(n * sizeof(*vars));
593 	i = 0;
594 	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
595 		for (vp = *vpp; vp; vp = vp->next) {
596 			if (!(vp->flags & VUNSET))
597 				vars[i++] = vp->text;
598 		}
599 	}
600 
601 	qsort(vars, n, sizeof(*vars), var_compare);
602 	for (i = 0; i < n; i++) {
603 		/*
604 		 * Skip improper variable names so the output remains usable as
605 		 * shell input.
606 		 */
607 		if (!isassignment(vars[i]))
608 			continue;
609 		s = strchr(vars[i], '=');
610 		s++;
611 		outbin(vars[i], s - vars[i], out1);
612 		out1qstr(s);
613 		out1c('\n');
614 	}
615 	ckfree(vars);
616 	INTON;
617 
618 	return 0;
619 }
620 
621 
622 
623 /*
624  * The export and readonly commands.
625  */
626 
627 int
628 exportcmd(int argc __unused, char **argv)
629 {
630 	struct var **vpp;
631 	struct var *vp;
632 	char **ap;
633 	char *name;
634 	char *p;
635 	char *cmdname;
636 	int ch, values;
637 	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
638 
639 	cmdname = argv[0];
640 	values = 0;
641 	while ((ch = nextopt("p")) != '\0') {
642 		switch (ch) {
643 		case 'p':
644 			values = 1;
645 			break;
646 		}
647 	}
648 
649 	if (values && *argptr != NULL)
650 		error("-p requires no arguments");
651 	if (*argptr != NULL) {
652 		for (ap = argptr; (name = *ap) != NULL; ap++) {
653 			if ((p = strchr(name, '=')) != NULL) {
654 				p++;
655 			} else {
656 				vp = find_var(name, NULL, NULL);
657 				if (vp != NULL) {
658 					vp->flags |= flag;
659 					if ((vp->flags & VEXPORT) && localevar(vp->text)) {
660 						change_env(vp->text, 1);
661 						setlocale(LC_ALL, "");
662 						updatecharset();
663 					}
664 					continue;
665 				}
666 			}
667 			setvar(name, p, flag);
668 		}
669 	} else {
670 		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
671 			for (vp = *vpp ; vp ; vp = vp->next) {
672 				if (vp->flags & flag) {
673 					if (values) {
674 						/*
675 						 * Skip improper variable names
676 						 * so the output remains usable
677 						 * as shell input.
678 						 */
679 						if (!isassignment(vp->text))
680 							continue;
681 						out1str(cmdname);
682 						out1c(' ');
683 					}
684 					if (values && !(vp->flags & VUNSET)) {
685 						outbin(vp->text,
686 						    vp->name_len + 1, out1);
687 						out1qstr(vp->text +
688 						    vp->name_len + 1);
689 					} else
690 						outbin(vp->text, vp->name_len,
691 						    out1);
692 					out1c('\n');
693 				}
694 			}
695 		}
696 	}
697 	return 0;
698 }
699 
700 
701 /*
702  * The "local" command.
703  */
704 
705 int
706 localcmd(int argc __unused, char **argv __unused)
707 {
708 	char *name;
709 
710 	if (! in_function())
711 		error("Not in a function");
712 	while ((name = *argptr++) != NULL) {
713 		mklocal(name);
714 	}
715 	return 0;
716 }
717 
718 
719 /*
720  * Make a variable a local variable.  When a variable is made local, it's
721  * value and flags are saved in a localvar structure.  The saved values
722  * will be restored when the shell function returns.  We handle the name
723  * "-" as a special case.
724  */
725 
726 void
727 mklocal(char *name)
728 {
729 	struct localvar *lvp;
730 	struct var **vpp;
731 	struct var *vp;
732 
733 	INTOFF;
734 	lvp = ckmalloc(sizeof (struct localvar));
735 	if (name[0] == '-' && name[1] == '\0') {
736 		lvp->text = ckmalloc(sizeof optlist);
737 		memcpy(lvp->text, optlist, sizeof optlist);
738 		vp = NULL;
739 	} else {
740 		vp = find_var(name, &vpp, NULL);
741 		if (vp == NULL) {
742 			if (strchr(name, '='))
743 				setvareq(savestr(name), VSTRFIXED | VNOLOCAL);
744 			else
745 				setvar(name, NULL, VSTRFIXED | VNOLOCAL);
746 			vp = *vpp;	/* the new variable */
747 			lvp->text = NULL;
748 			lvp->flags = VUNSET;
749 		} else {
750 			lvp->text = vp->text;
751 			lvp->flags = vp->flags;
752 			vp->flags |= VSTRFIXED|VTEXTFIXED;
753 			if (name[vp->name_len] == '=')
754 				setvareq(savestr(name), VNOLOCAL);
755 		}
756 	}
757 	lvp->vp = vp;
758 	lvp->next = localvars;
759 	localvars = lvp;
760 	INTON;
761 }
762 
763 
764 /*
765  * Called after a function returns.
766  */
767 
768 void
769 poplocalvars(void)
770 {
771 	struct localvar *lvp;
772 	struct var *vp;
773 
774 	while ((lvp = localvars) != NULL) {
775 		localvars = lvp->next;
776 		vp = lvp->vp;
777 		if (vp == NULL) {	/* $- saved */
778 			memcpy(optlist, lvp->text, sizeof optlist);
779 			ckfree(lvp->text);
780 			optschanged();
781 		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
782 			unsetvar(vp->text);
783 		} else {
784 			if ((vp->flags & VTEXTFIXED) == 0)
785 				ckfree(vp->text);
786 			vp->flags = lvp->flags;
787 			vp->text = lvp->text;
788 		}
789 		ckfree(lvp);
790 	}
791 }
792 
793 
794 int
795 setvarcmd(int argc, char **argv)
796 {
797 	if (argc <= 2)
798 		return unsetcmd(argc, argv);
799 	else if (argc == 3)
800 		setvar(argv[1], argv[2], 0);
801 	else
802 		error("too many arguments");
803 	return 0;
804 }
805 
806 
807 /*
808  * The unset builtin command.
809  */
810 
811 int
812 unsetcmd(int argc __unused, char **argv __unused)
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("vf")) != '\0') {
821 		if (i == 'f')
822 			flg_func = 1;
823 		else
824 			flg_var = 1;
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);
834 	}
835 	return ret;
836 }
837 
838 
839 /*
840  * Unset the specified variable.
841  */
842 
843 int
844 unsetvar(const char *s)
845 {
846 	struct var **vpp;
847 	struct var *vp;
848 
849 	vp = find_var(s, &vpp, NULL);
850 	if (vp == NULL)
851 		return (0);
852 	if (vp->flags & VREADONLY)
853 		return (1);
854 	INTOFF;
855 	if (vp->text[vp->name_len + 1] != '\0')
856 		setvar(s, nullstr, 0);
857 	if ((vp->flags & VEXPORT) && localevar(vp->text)) {
858 		change_env(__DECONST(char *, s), 0);
859 		setlocale(LC_ALL, "");
860 		updatecharset();
861 	}
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 	INTON;
871 	return (0);
872 }
873 
874 
875 
876 /*
877  * Returns true if the two strings specify the same variable.  The first
878  * variable name is terminated by '='; the second may be terminated by
879  * either '=' or '\0'.
880  */
881 
882 static int
883 varequal(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 characters 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 }
931