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var.c revision 1.33 
      1 /*	$NetBSD: var.c,v 1.33 2003/08/07 09:05:39 agc Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1991, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * Kenneth Almquist.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. Neither the name of the University nor the names of its contributors
     19  *    may be used to endorse or promote products derived from this software
     20  *    without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  */
     34 
     35 #include <sys/cdefs.h>
     36 #ifndef lint
     37 #if 0
     38 static char sccsid[] = "@(#)var.c	8.3 (Berkeley) 5/4/95";
     39 #else
     40 __RCSID("$NetBSD: var.c,v 1.33 2003/08/07 09:05:39 agc Exp $");
     41 #endif
     42 #endif /* not lint */
     43 
     44 #include <unistd.h>
     45 #include <stdlib.h>
     46 #include <paths.h>
     47 
     48 /*
     49  * Shell variables.
     50  */
     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 "show.h"
     67 #ifndef SMALL
     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 #if ATTY
     84 struct var vatty;
     85 #endif
     86 #ifndef SMALL
     87 struct var vhistsize;
     88 struct var vterm;
     89 #endif
     90 struct var vifs;
     91 struct var vmail;
     92 struct var vmpath;
     93 struct var vpath;
     94 struct var vps1;
     95 struct var vps2;
     96 struct var vps4;
     97 struct var vvers;
     98 struct var voptind;
     99 
    100 const struct varinit varinit[] = {
    101 #if ATTY
    102 	{ &vatty,	VSTRFIXED|VTEXTFIXED|VUNSET,	"ATTY=",
    103 	  NULL },
    104 #endif
    105 #ifndef SMALL
    106 	{ &vhistsize,	VSTRFIXED|VTEXTFIXED|VUNSET,	"HISTSIZE=",
    107 	  sethistsize },
    108 #endif
    109 	{ &vifs,	VSTRFIXED|VTEXTFIXED,		"IFS= \t\n",
    110 	  NULL },
    111 	{ &vmail,	VSTRFIXED|VTEXTFIXED|VUNSET,	"MAIL=",
    112 	  NULL },
    113 	{ &vmpath,	VSTRFIXED|VTEXTFIXED|VUNSET,	"MAILPATH=",
    114 	  NULL },
    115 	{ &vpath,	VSTRFIXED|VTEXTFIXED,		"PATH=" _PATH_DEFPATH,
    116 	  changepath },
    117 	/*
    118 	 * vps1 depends on uid
    119 	 */
    120 	{ &vps2,	VSTRFIXED|VTEXTFIXED,		"PS2=> ",
    121 	  NULL },
    122 	{ &vps4,	VSTRFIXED|VTEXTFIXED,		"PS4=+ ",
    123 	  NULL },
    124 #ifndef SMALL
    125 	{ &vterm,	VSTRFIXED|VTEXTFIXED|VUNSET,	"TERM=",
    126 	  setterm },
    127 #endif
    128 	{ &voptind,	VSTRFIXED|VTEXTFIXED|VNOFUNC,	"OPTIND=1",
    129 	  getoptsreset },
    130 	{ NULL,	0,				NULL,
    131 	  NULL }
    132 };
    133 
    134 struct var *vartab[VTABSIZE];
    135 
    136 STATIC struct var **hashvar(const char *);
    137 STATIC int varequal(const char *, const char *);
    138 
    139 /*
    140  * Initialize the varable symbol tables and import the environment
    141  */
    142 
    143 #ifdef mkinit
    144 INCLUDE "var.h"
    145 MKINIT char **environ;
    146 INIT {
    147 	char **envp;
    148 
    149 	initvar();
    150 	for (envp = environ ; *envp ; envp++) {
    151 		if (strchr(*envp, '=')) {
    152 			setvareq(*envp, VEXPORT|VTEXTFIXED);
    153 		}
    154 	}
    155 }
    156 #endif
    157 
    158 
    159 /*
    160  * This routine initializes the builtin variables.  It is called when the
    161  * shell is initialized and again when a shell procedure is spawned.
    162  */
    163 
    164 void
    165 initvar(void)
    166 {
    167 	const struct varinit *ip;
    168 	struct var *vp;
    169 	struct var **vpp;
    170 
    171 	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
    172 		if ((vp->flags & VEXPORT) == 0) {
    173 			vpp = hashvar(ip->text);
    174 			vp->next = *vpp;
    175 			*vpp = vp;
    176 			vp->text = strdup(ip->text);
    177 			vp->flags = ip->flags;
    178 			vp->func = ip->func;
    179 		}
    180 	}
    181 	/*
    182 	 * PS1 depends on uid
    183 	 */
    184 	if ((vps1.flags & VEXPORT) == 0) {
    185 		vpp = hashvar("PS1=");
    186 		vps1.next = *vpp;
    187 		*vpp = &vps1;
    188 		vps1.text = strdup(geteuid() ? "PS1=$ " : "PS1=# ");
    189 		vps1.flags = VSTRFIXED|VTEXTFIXED;
    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 *volatile savehandler = handler;
    202 	int err = 0;
    203 #ifdef __GNUC__
    204 	(void) &err;
    205 #endif
    206 
    207 	if (setjmp(jmploc.loc))
    208 		err = 1;
    209 	else {
    210 		handler = &jmploc;
    211 		setvar(name, val, flags);
    212 	}
    213 	handler = savehandler;
    214 	return err;
    215 }
    216 
    217 /*
    218  * Set the value of a variable.  The flags argument is ored 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 	const char *q;
    227 	char *d;
    228 	int len;
    229 	int namelen;
    230 	char *nameeq;
    231 	int isbad;
    232 
    233 	isbad = 0;
    234 	p = name;
    235 	if (! is_name(*p))
    236 		isbad = 1;
    237 	p++;
    238 	for (;;) {
    239 		if (! is_in_name(*p)) {
    240 			if (*p == '\0' || *p == '=')
    241 				break;
    242 			isbad = 1;
    243 		}
    244 		p++;
    245 	}
    246 	namelen = p - name;
    247 	if (isbad)
    248 		error("%.*s: bad variable name", namelen, name);
    249 	len = namelen + 2;		/* 2 is space for '=' and '\0' */
    250 	if (val == NULL) {
    251 		flags |= VUNSET;
    252 	} else {
    253 		len += strlen(val);
    254 	}
    255 	d = nameeq = ckmalloc(len);
    256 	q = name;
    257 	while (--namelen >= 0)
    258 		*d++ = *q++;
    259 	*d++ = '=';
    260 	*d = '\0';
    261 	if (val)
    262 		scopy(val, d);
    263 	setvareq(nameeq, flags);
    264 }
    265 
    266 
    267 
    268 /*
    269  * Same as setvar except that the variable and value are passed in
    270  * the first argument as name=value.  Since the first argument will
    271  * be actually stored in the table, it should not be a string that
    272  * will go away.
    273  */
    274 
    275 void
    276 setvareq(char *s, int flags)
    277 {
    278 	struct var *vp, **vpp;
    279 
    280 	if (aflag)
    281 		flags |= VEXPORT;
    282 	vpp = hashvar(s);
    283 	for (vp = *vpp ; vp ; vp = vp->next) {
    284 		if (varequal(s, vp->text)) {
    285 			if (vp->flags & VREADONLY) {
    286 				size_t len = strchr(s, '=') - s;
    287 				error("%.*s: is read only", len, s);
    288 			}
    289 			if (flags & VNOSET)
    290 				return;
    291 			INTOFF;
    292 
    293 			if (vp->func && (flags & VNOFUNC) == 0)
    294 				(*vp->func)(strchr(s, '=') + 1);
    295 
    296 			if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
    297 				ckfree(vp->text);
    298 
    299 			vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
    300 			vp->flags |= flags & ~VNOFUNC;
    301 			vp->text = s;
    302 
    303 			/*
    304 			 * We could roll this to a function, to handle it as
    305 			 * a regular variable function callback, but why bother?
    306 			 */
    307 			if (vp == &vmpath || (vp == &vmail && ! mpathset()))
    308 				chkmail(1);
    309 			INTON;
    310 			return;
    311 		}
    312 	}
    313 	/* not found */
    314 	if (flags & VNOSET)
    315 		return;
    316 	vp = ckmalloc(sizeof (*vp));
    317 	vp->flags = flags & ~VNOFUNC;
    318 	vp->text = s;
    319 	vp->next = *vpp;
    320 	vp->func = NULL;
    321 	*vpp = vp;
    322 }
    323 
    324 
    325 
    326 /*
    327  * Process a linked list of variable assignments.
    328  */
    329 
    330 void
    331 listsetvar(struct strlist *list, int flags)
    332 {
    333 	struct strlist *lp;
    334 
    335 	INTOFF;
    336 	for (lp = list ; lp ; lp = lp->next) {
    337 		setvareq(savestr(lp->text), flags);
    338 	}
    339 	INTON;
    340 }
    341 
    342 void
    343 listmklocal(struct strlist *list, int flags)
    344 {
    345 	struct strlist *lp;
    346 
    347 	for (lp = list ; lp ; lp = lp->next)
    348 		mklocal(lp->text, flags);
    349 }
    350 
    351 
    352 /*
    353  * Find the value of a variable.  Returns NULL if not set.
    354  */
    355 
    356 char *
    357 lookupvar(const char *name)
    358 {
    359 	struct var *v;
    360 
    361 	for (v = *hashvar(name) ; v ; v = v->next) {
    362 		if (varequal(v->text, name)) {
    363 			if (v->flags & VUNSET)
    364 				return NULL;
    365 			return strchr(v->text, '=') + 1;
    366 		}
    367 	}
    368 	return NULL;
    369 }
    370 
    371 
    372 
    373 /*
    374  * Search the environment of a builtin command.  If the second argument
    375  * is nonzero, return the value of a variable even if it hasn't been
    376  * exported.
    377  */
    378 
    379 char *
    380 bltinlookup(const char *name, int doall)
    381 {
    382 	struct strlist *sp;
    383 	struct var *v;
    384 
    385 	for (sp = cmdenviron ; sp ; sp = sp->next) {
    386 		if (varequal(sp->text, name))
    387 			return strchr(sp->text, '=') + 1;
    388 	}
    389 	for (v = *hashvar(name) ; v ; v = v->next) {
    390 		if (varequal(v->text, name)) {
    391 			if ((v->flags & VUNSET)
    392 			 || (!doall && (v->flags & VEXPORT) == 0))
    393 				return NULL;
    394 			return strchr(v->text, '=') + 1;
    395 		}
    396 	}
    397 	return NULL;
    398 }
    399 
    400 
    401 
    402 /*
    403  * Generate a list of exported variables.  This routine is used to construct
    404  * the third argument to execve when executing a program.
    405  */
    406 
    407 char **
    408 environment(void)
    409 {
    410 	int nenv;
    411 	struct var **vpp;
    412 	struct var *vp;
    413 	char **env;
    414 	char **ep;
    415 
    416 	nenv = 0;
    417 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
    418 		for (vp = *vpp ; vp ; vp = vp->next)
    419 			if (vp->flags & VEXPORT)
    420 				nenv++;
    421 	}
    422 	ep = env = stalloc((nenv + 1) * sizeof *env);
    423 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
    424 		for (vp = *vpp ; vp ; vp = vp->next)
    425 			if (vp->flags & VEXPORT)
    426 				*ep++ = vp->text;
    427 	}
    428 	*ep = NULL;
    429 	return env;
    430 }
    431 
    432 
    433 /*
    434  * Called when a shell procedure is invoked to clear out nonexported
    435  * variables.  It is also necessary to reallocate variables of with
    436  * VSTACK set since these are currently allocated on the stack.
    437  */
    438 
    439 #ifdef mkinit
    440 void shprocvar(void);
    441 
    442 SHELLPROC {
    443 	shprocvar();
    444 }
    445 #endif
    446 
    447 void
    448 shprocvar(void)
    449 {
    450 	struct var **vpp;
    451 	struct var *vp, **prev;
    452 
    453 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
    454 		for (prev = vpp ; (vp = *prev) != NULL ; ) {
    455 			if ((vp->flags & VEXPORT) == 0) {
    456 				*prev = vp->next;
    457 				if ((vp->flags & VTEXTFIXED) == 0)
    458 					ckfree(vp->text);
    459 				if ((vp->flags & VSTRFIXED) == 0)
    460 					ckfree(vp);
    461 			} else {
    462 				if (vp->flags & VSTACK) {
    463 					vp->text = savestr(vp->text);
    464 					vp->flags &=~ VSTACK;
    465 				}
    466 				prev = &vp->next;
    467 			}
    468 		}
    469 	}
    470 	initvar();
    471 }
    472 
    473 
    474 
    475 /*
    476  * Command to list all variables which are set.  Currently this command
    477  * is invoked from the set command when the set command is called without
    478  * any variables.
    479  */
    480 
    481 void
    482 print_quoted(const char *p)
    483 {
    484 	const char *q;
    485 
    486 	if (strcspn(p, "|&;<>()$`\\\"' \t\n*?[]#~=%") == strlen(p)) {
    487 		out1fmt("%s", p);
    488 		return;
    489 	}
    490 	while (*p) {
    491 		if (*p == '\'') {
    492 			out1fmt("\\'");
    493 			p++;
    494 			continue;
    495 		}
    496 		q = index(p, '\'');
    497 		if (!q) {
    498 			out1fmt("'%s'", p );
    499 			return;
    500 		}
    501 		out1fmt("'%.*s'", (int)(q - p), p );
    502 		p = q;
    503 	}
    504 }
    505 
    506 static int
    507 sort_var(const void *v_v1, const void *v_v2)
    508 {
    509 	const struct var * const *v1 = v_v1;
    510 	const struct var * const *v2 = v_v2;
    511 
    512 	/* XXX Will anyone notice we include the '=' of the shorter name? */
    513 	return strcoll((*v1)->text, (*v2)->text);
    514 }
    515 
    516 /*
    517  * POSIX requires that 'set' (but not export or readonly) output the
    518  * variables in lexicographic order - by the locale's collating order (sigh).
    519  * Maybe we could keep them in an ordered balanced binary tree
    520  * instead of hashed lists.
    521  * For now just roll 'em through qsort for printing...
    522  */
    523 
    524 int
    525 showvars(const char *name, int flag, int show_value)
    526 {
    527 	struct var **vpp;
    528 	struct var *vp;
    529 	const char *p;
    530 
    531 	static struct var **list;	/* static in case we are interrupted */
    532 	static int list_len;
    533 	int count = 0;
    534 
    535 	if (!list) {
    536 		list_len = 32;
    537 		list = ckmalloc(list_len * sizeof *list);
    538 	}
    539 
    540 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
    541 		for (vp = *vpp ; vp ; vp = vp->next) {
    542 			if (flag && !(vp->flags & flag))
    543 				continue;
    544 			if (vp->flags & VUNSET && !(show_value & 2))
    545 				continue;
    546 			if (count >= list_len) {
    547 				list = ckrealloc(list,
    548 					(list_len << 1) * sizeof *list);
    549 				list_len <<= 1;
    550 			}
    551 			list[count++] = vp;
    552 		}
    553 	}
    554 
    555 	qsort(list, count, sizeof *list, sort_var);
    556 
    557 	for (vpp = list; count--; vpp++) {
    558 		vp = *vpp;
    559 		if (name)
    560 			out1fmt("%s ", name);
    561 		for (p = vp->text ; *p != '=' ; p++)
    562 			out1c(*p);
    563 		if (!(vp->flags & VUNSET) && show_value) {
    564 			out1fmt("=");
    565 			print_quoted(++p);
    566 		}
    567 		out1c('\n');
    568 	}
    569 	return 0;
    570 }
    571 
    572 
    573 
    574 /*
    575  * The export and readonly commands.
    576  */
    577 
    578 int
    579 exportcmd(int argc, char **argv)
    580 {
    581 	struct var **vpp;
    582 	struct var *vp;
    583 	char *name;
    584 	const char *p;
    585 	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
    586 	int pflag;
    587 
    588 	pflag = nextopt("p") == 'p' ? 3 : 0;
    589 	if (argc <= 1 || pflag) {
    590 		showvars( pflag ? argv[0] : 0, flag, pflag );
    591 		return 0;
    592 	}
    593 
    594 	while ((name = *argptr++) != NULL) {
    595 		if ((p = strchr(name, '=')) != NULL) {
    596 			p++;
    597 		} else {
    598 			vpp = hashvar(name);
    599 			for (vp = *vpp ; vp ; vp = vp->next) {
    600 				if (varequal(vp->text, name)) {
    601 					vp->flags |= flag;
    602 					goto found;
    603 				}
    604 			}
    605 		}
    606 		setvar(name, p, flag);
    607 found:;
    608 	}
    609 	return 0;
    610 }
    611 
    612 
    613 /*
    614  * The "local" command.
    615  */
    616 
    617 int
    618 localcmd(int argc, char **argv)
    619 {
    620 	char *name;
    621 
    622 	if (! in_function())
    623 		error("Not in a function");
    624 	while ((name = *argptr++) != NULL) {
    625 		mklocal(name, 0);
    626 	}
    627 	return 0;
    628 }
    629 
    630 
    631 /*
    632  * Make a variable a local variable.  When a variable is made local, it's
    633  * value and flags are saved in a localvar structure.  The saved values
    634  * will be restored when the shell function returns.  We handle the name
    635  * "-" as a special case.
    636  */
    637 
    638 void
    639 mklocal(const char *name, int flags)
    640 {
    641 	struct localvar *lvp;
    642 	struct var **vpp;
    643 	struct var *vp;
    644 
    645 	INTOFF;
    646 	lvp = ckmalloc(sizeof (struct localvar));
    647 	if (name[0] == '-' && name[1] == '\0') {
    648 		char *p;
    649 		p = ckmalloc(sizeof_optlist);
    650 		lvp->text = memcpy(p, optlist, sizeof_optlist);
    651 		vp = NULL;
    652 	} else {
    653 		vpp = hashvar(name);
    654 		for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next);
    655 		if (vp == NULL) {
    656 			if (strchr(name, '='))
    657 				setvareq(savestr(name), VSTRFIXED|flags);
    658 			else
    659 				setvar(name, NULL, VSTRFIXED|flags);
    660 			vp = *vpp;	/* the new variable */
    661 			lvp->text = NULL;
    662 			lvp->flags = VUNSET;
    663 		} else {
    664 			lvp->text = vp->text;
    665 			lvp->flags = vp->flags;
    666 			vp->flags |= VSTRFIXED|VTEXTFIXED;
    667 			if (strchr(name, '='))
    668 				setvareq(savestr(name), flags);
    669 		}
    670 	}
    671 	lvp->vp = vp;
    672 	lvp->next = localvars;
    673 	localvars = lvp;
    674 	INTON;
    675 }
    676 
    677 
    678 /*
    679  * Called after a function returns.
    680  */
    681 
    682 void
    683 poplocalvars(void)
    684 {
    685 	struct localvar *lvp;
    686 	struct var *vp;
    687 
    688 	while ((lvp = localvars) != NULL) {
    689 		localvars = lvp->next;
    690 		vp = lvp->vp;
    691 		TRACE(("poplocalvar %s", vp ? vp->text : "-"));
    692 		if (vp == NULL) {	/* $- saved */
    693 			memcpy(optlist, lvp->text, sizeof_optlist);
    694 			ckfree(lvp->text);
    695 		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
    696 			(void)unsetvar(vp->text, 0);
    697 		} else {
    698 			if (vp->func && (vp->flags & VNOFUNC) == 0)
    699 				(*vp->func)(strchr(lvp->text, '=') + 1);
    700 			if ((vp->flags & VTEXTFIXED) == 0)
    701 				ckfree(vp->text);
    702 			vp->flags = lvp->flags;
    703 			vp->text = lvp->text;
    704 		}
    705 		ckfree(lvp);
    706 	}
    707 }
    708 
    709 
    710 int
    711 setvarcmd(int argc, char **argv)
    712 {
    713 	if (argc <= 2)
    714 		return unsetcmd(argc, argv);
    715 	else if (argc == 3)
    716 		setvar(argv[1], argv[2], 0);
    717 	else
    718 		error("List assignment not implemented");
    719 	return 0;
    720 }
    721 
    722 
    723 /*
    724  * The unset builtin command.  We unset the function before we unset the
    725  * variable to allow a function to be unset when there is a readonly variable
    726  * with the same name.
    727  */
    728 
    729 int
    730 unsetcmd(int argc, char **argv)
    731 {
    732 	char **ap;
    733 	int i;
    734 	int flg_func = 0;
    735 	int flg_var = 0;
    736 	int ret = 0;
    737 
    738 	while ((i = nextopt("evf")) != '\0') {
    739 		if (i == 'f')
    740 			flg_func = 1;
    741 		else
    742 			flg_var = i;
    743 	}
    744 	if (flg_func == 0 && flg_var == 0)
    745 		flg_var = 1;
    746 
    747 	for (ap = argptr; *ap ; ap++) {
    748 		if (flg_func)
    749 			ret |= unsetfunc(*ap);
    750 		if (flg_var)
    751 			ret |= unsetvar(*ap, flg_var == 'e');
    752 	}
    753 	return ret;
    754 }
    755 
    756 
    757 /*
    758  * Unset the specified variable.
    759  */
    760 
    761 int
    762 unsetvar(const char *s, int unexport)
    763 {
    764 	struct var **vpp;
    765 	struct var *vp;
    766 
    767 	vpp = hashvar(s);
    768 	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
    769 		if (varequal(vp->text, s)) {
    770 			if (vp->flags & VREADONLY)
    771 				return (1);
    772 			INTOFF;
    773 			if (unexport) {
    774 				vp->flags &= ~VEXPORT;
    775 			} else {
    776 				if (*(strchr(vp->text, '=') + 1) != '\0')
    777 					setvar(s, nullstr, 0);
    778 				vp->flags &= ~VEXPORT;
    779 				vp->flags |= VUNSET;
    780 				if ((vp->flags & VSTRFIXED) == 0) {
    781 					if ((vp->flags & VTEXTFIXED) == 0)
    782 						ckfree(vp->text);
    783 					*vpp = vp->next;
    784 					ckfree(vp);
    785 				}
    786 			}
    787 			INTON;
    788 			return (0);
    789 		}
    790 	}
    791 
    792 	return (1);
    793 }
    794 
    795 
    796 
    797 /*
    798  * Find the appropriate entry in the hash table from the name.
    799  */
    800 
    801 STATIC struct var **
    802 hashvar(const char *p)
    803 {
    804 	unsigned int hashval;
    805 
    806 	hashval = ((unsigned char) *p) << 4;
    807 	while (*p && *p != '=')
    808 		hashval += (unsigned char) *p++;
    809 	return &vartab[hashval % VTABSIZE];
    810 }
    811 
    812 
    813 
    814 /*
    815  * Returns true if the two strings specify the same varable.  The first
    816  * variable name is terminated by '='; the second may be terminated by
    817  * either '=' or '\0'.
    818  */
    819 
    820 STATIC int
    821 varequal(const char *p, const char *q)
    822 {
    823 	while (*p == *q++) {
    824 		if (*p++ == '=')
    825 			return 1;
    826 	}
    827 	if (*p == '=' && *(q - 1) == '\0')
    828 		return 1;
    829 	return 0;
    830 }
    831