Home | History | Annotate | Line # | Download | only in sh
var.c revision 1.29 
      1 /*	$NetBSD: var.c,v 1.29 2002/09/27 18:56:58 christos 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. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *	This product includes software developed by the University of
     21  *	California, Berkeley and its contributors.
     22  * 4. Neither the name of the University nor the names of its contributors
     23  *    may be used to endorse or promote products derived from this software
     24  *    without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     36  * SUCH DAMAGE.
     37  */
     38 
     39 #include <sys/cdefs.h>
     40 #ifndef lint
     41 #if 0
     42 static char sccsid[] = "@(#)var.c	8.3 (Berkeley) 5/4/95";
     43 #else
     44 __RCSID("$NetBSD: var.c,v 1.29 2002/09/27 18:56:58 christos Exp $");
     45 #endif
     46 #endif /* not lint */
     47 
     48 #include <unistd.h>
     49 #include <stdlib.h>
     50 #include <paths.h>
     51 
     52 /*
     53  * Shell variables.
     54  */
     55 
     56 #include "shell.h"
     57 #include "output.h"
     58 #include "expand.h"
     59 #include "nodes.h"	/* for other headers */
     60 #include "eval.h"	/* defines cmdenviron */
     61 #include "exec.h"
     62 #include "syntax.h"
     63 #include "options.h"
     64 #include "mail.h"
     65 #include "var.h"
     66 #include "memalloc.h"
     67 #include "error.h"
     68 #include "mystring.h"
     69 #include "parser.h"
     70 #ifndef SMALL
     71 #include "myhistedit.h"
     72 #endif
     73 
     74 
     75 #define VTABSIZE 39
     76 
     77 
     78 struct varinit {
     79 	struct var *var;
     80 	int flags;
     81 	const char *text;
     82 	void (*func) __P((const char *));
     83 };
     84 
     85 
     86 #if ATTY
     87 struct var vatty;
     88 #endif
     89 #ifndef SMALL
     90 struct var vhistsize;
     91 struct var vterm;
     92 #endif
     93 struct var vifs;
     94 struct var vmail;
     95 struct var vmpath;
     96 struct var vpath;
     97 struct var vps1;
     98 struct var vps2;
     99 struct var vvers;
    100 struct var voptind;
    101 
    102 const struct varinit varinit[] = {
    103 #if ATTY
    104 	{ &vatty,	VSTRFIXED|VTEXTFIXED|VUNSET,	"ATTY=",
    105 	  NULL },
    106 #endif
    107 #ifndef SMALL
    108 	{ &vhistsize,	VSTRFIXED|VTEXTFIXED|VUNSET,	"HISTSIZE=",
    109 	  sethistsize },
    110 #endif
    111 	{ &vifs,	VSTRFIXED|VTEXTFIXED,		"IFS= \t\n",
    112 	  NULL },
    113 	{ &vmail,	VSTRFIXED|VTEXTFIXED|VUNSET,	"MAIL=",
    114 	  NULL },
    115 	{ &vmpath,	VSTRFIXED|VTEXTFIXED|VUNSET,	"MAILPATH=",
    116 	  NULL },
    117 	{ &vpath,	VSTRFIXED|VTEXTFIXED,		"PATH=" _PATH_DEFPATH,
    118 	  changepath },
    119 	/*
    120 	 * vps1 depends on uid
    121 	 */
    122 	{ &vps2,	VSTRFIXED|VTEXTFIXED,		"PS2=> ",
    123 	  NULL },
    124 #ifndef SMALL
    125 	{ &vterm,	VSTRFIXED|VTEXTFIXED|VUNSET,	"TERM=",
    126 	  setterm },
    127 #endif
    128 	{ &voptind,	VSTRFIXED|VTEXTFIXED,		"OPTIND=1",
    129 	  getoptsreset },
    130 	{ NULL,	0,				NULL,
    131 	  NULL }
    132 };
    133 
    134 struct var *vartab[VTABSIZE];
    135 
    136 STATIC struct var **hashvar __P((const char *));
    137 STATIC int varequal __P((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() {
    166 	const struct varinit *ip;
    167 	struct var *vp;
    168 	struct var **vpp;
    169 
    170 	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
    171 		if ((vp->flags & VEXPORT) == 0) {
    172 			vpp = hashvar(ip->text);
    173 			vp->next = *vpp;
    174 			*vpp = vp;
    175 			vp->text = strdup(ip->text);
    176 			vp->flags = ip->flags;
    177 			vp->func = ip->func;
    178 		}
    179 	}
    180 	/*
    181 	 * PS1 depends on uid
    182 	 */
    183 	if ((vps1.flags & VEXPORT) == 0) {
    184 		vpp = hashvar("PS1=");
    185 		vps1.next = *vpp;
    186 		*vpp = &vps1;
    187 		vps1.text = strdup(geteuid() ? "PS1=$ " : "PS1=# ");
    188 		vps1.flags = VSTRFIXED|VTEXTFIXED;
    189 	}
    190 }
    191 
    192 /*
    193  * Safe version of setvar, returns 1 on success 0 on failure.
    194  */
    195 
    196 int
    197 setvarsafe(name, val, flags)
    198 	const char *name, *val;
    199 	int flags;
    200 {
    201 	struct jmploc jmploc;
    202 	struct jmploc *volatile savehandler = handler;
    203 	int err = 0;
    204 #ifdef __GNUC__
    205 	(void) &err;
    206 #endif
    207 
    208 	if (setjmp(jmploc.loc))
    209 		err = 1;
    210 	else {
    211 		handler = &jmploc;
    212 		setvar(name, val, flags);
    213 	}
    214 	handler = savehandler;
    215 	return err;
    216 }
    217 
    218 /*
    219  * Set the value of a variable.  The flags argument is ored with the
    220  * flags of the variable.  If val is NULL, the variable is unset.
    221  */
    222 
    223 void
    224 setvar(name, val, flags)
    225 	const char *name, *val;
    226 	int flags;
    227 {
    228 	const char *p;
    229 	const char *q;
    230 	char *d;
    231 	int len;
    232 	int namelen;
    233 	char *nameeq;
    234 	int isbad;
    235 
    236 	isbad = 0;
    237 	p = name;
    238 	if (! is_name(*p))
    239 		isbad = 1;
    240 	p++;
    241 	for (;;) {
    242 		if (! is_in_name(*p)) {
    243 			if (*p == '\0' || *p == '=')
    244 				break;
    245 			isbad = 1;
    246 		}
    247 		p++;
    248 	}
    249 	namelen = p - name;
    250 	if (isbad)
    251 		error("%.*s: bad variable name", namelen, name);
    252 	len = namelen + 2;		/* 2 is space for '=' and '\0' */
    253 	if (val == NULL) {
    254 		flags |= VUNSET;
    255 	} else {
    256 		len += strlen(val);
    257 	}
    258 	d = nameeq = ckmalloc(len);
    259 	q = name;
    260 	while (--namelen >= 0)
    261 		*d++ = *q++;
    262 	*d++ = '=';
    263 	*d = '\0';
    264 	if (val)
    265 		scopy(val, d);
    266 	setvareq(nameeq, flags);
    267 }
    268 
    269 
    270 
    271 /*
    272  * Same as setvar except that the variable and value are passed in
    273  * the first argument as name=value.  Since the first argument will
    274  * be actually stored in the table, it should not be a string that
    275  * will go away.
    276  */
    277 
    278 void
    279 setvareq(s, flags)
    280 	char *s;
    281 	int flags;
    282 {
    283 	struct var *vp, **vpp;
    284 
    285 	if (aflag)
    286 		flags |= VEXPORT;
    287 	vpp = hashvar(s);
    288 	for (vp = *vpp ; vp ; vp = vp->next) {
    289 		if (varequal(s, vp->text)) {
    290 			if (vp->flags & VREADONLY) {
    291 				size_t len = strchr(s, '=') - s;
    292 				error("%.*s: is read only", len, s);
    293 			}
    294 			INTOFF;
    295 
    296 			if (vp->func && (flags & VNOFUNC) == 0)
    297 				(*vp->func)(strchr(s, '=') + 1);
    298 
    299 			if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
    300 				ckfree(vp->text);
    301 
    302 			vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
    303 			vp->flags |= flags;
    304 			vp->text = s;
    305 
    306 			/*
    307 			 * We could roll this to a function, to handle it as
    308 			 * a regular variable function callback, but why bother?
    309 			 */
    310 			if (vp == &vmpath || (vp == &vmail && ! mpathset()))
    311 				chkmail(1);
    312 			INTON;
    313 			return;
    314 		}
    315 	}
    316 	/* not found */
    317 	vp = ckmalloc(sizeof (*vp));
    318 	vp->flags = flags;
    319 	vp->text = s;
    320 	vp->next = *vpp;
    321 	vp->func = NULL;
    322 	*vpp = vp;
    323 }
    324 
    325 
    326 
    327 /*
    328  * Process a linked list of variable assignments.
    329  */
    330 
    331 void
    332 listsetvar(list)
    333 	struct strlist *list;
    334 	{
    335 	struct strlist *lp;
    336 
    337 	INTOFF;
    338 	for (lp = list ; lp ; lp = lp->next) {
    339 		setvareq(savestr(lp->text), 0);
    340 	}
    341 	INTON;
    342 }
    343 
    344 
    345 
    346 /*
    347  * Find the value of a variable.  Returns NULL if not set.
    348  */
    349 
    350 char *
    351 lookupvar(name)
    352 	const char *name;
    353 	{
    354 	struct var *v;
    355 
    356 	for (v = *hashvar(name) ; v ; v = v->next) {
    357 		if (varequal(v->text, name)) {
    358 			if (v->flags & VUNSET)
    359 				return NULL;
    360 			return strchr(v->text, '=') + 1;
    361 		}
    362 	}
    363 	return NULL;
    364 }
    365 
    366 
    367 
    368 /*
    369  * Search the environment of a builtin command.  If the second argument
    370  * is nonzero, return the value of a variable even if it hasn't been
    371  * exported.
    372  */
    373 
    374 char *
    375 bltinlookup(name, doall)
    376 	const char *name;
    377 	int doall;
    378 {
    379 	struct strlist *sp;
    380 	struct var *v;
    381 
    382 	for (sp = cmdenviron ; sp ; sp = sp->next) {
    383 		if (varequal(sp->text, name))
    384 			return strchr(sp->text, '=') + 1;
    385 	}
    386 	for (v = *hashvar(name) ; v ; v = v->next) {
    387 		if (varequal(v->text, name)) {
    388 			if ((v->flags & VUNSET)
    389 			 || (!doall && (v->flags & VEXPORT) == 0))
    390 				return NULL;
    391 			return strchr(v->text, '=') + 1;
    392 		}
    393 	}
    394 	return NULL;
    395 }
    396 
    397 
    398 
    399 /*
    400  * Generate a list of exported variables.  This routine is used to construct
    401  * the third argument to execve when executing a program.
    402  */
    403 
    404 char **
    405 environment() {
    406 	int nenv;
    407 	struct var **vpp;
    408 	struct var *vp;
    409 	char **env;
    410 	char **ep;
    411 
    412 	nenv = 0;
    413 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
    414 		for (vp = *vpp ; vp ; vp = vp->next)
    415 			if (vp->flags & VEXPORT)
    416 				nenv++;
    417 	}
    418 	ep = env = stalloc((nenv + 1) * sizeof *env);
    419 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
    420 		for (vp = *vpp ; vp ; vp = vp->next)
    421 			if (vp->flags & VEXPORT)
    422 				*ep++ = vp->text;
    423 	}
    424 	*ep = NULL;
    425 	return env;
    426 }
    427 
    428 
    429 /*
    430  * Called when a shell procedure is invoked to clear out nonexported
    431  * variables.  It is also necessary to reallocate variables of with
    432  * VSTACK set since these are currently allocated on the stack.
    433  */
    434 
    435 #ifdef mkinit
    436 void shprocvar __P((void));
    437 
    438 SHELLPROC {
    439 	shprocvar();
    440 }
    441 #endif
    442 
    443 void
    444 shprocvar() {
    445 	struct var **vpp;
    446 	struct var *vp, **prev;
    447 
    448 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
    449 		for (prev = vpp ; (vp = *prev) != NULL ; ) {
    450 			if ((vp->flags & VEXPORT) == 0) {
    451 				*prev = vp->next;
    452 				if ((vp->flags & VTEXTFIXED) == 0)
    453 					ckfree(vp->text);
    454 				if ((vp->flags & VSTRFIXED) == 0)
    455 					ckfree(vp);
    456 			} else {
    457 				if (vp->flags & VSTACK) {
    458 					vp->text = savestr(vp->text);
    459 					vp->flags &=~ VSTACK;
    460 				}
    461 				prev = &vp->next;
    462 			}
    463 		}
    464 	}
    465 	initvar();
    466 }
    467 
    468 
    469 
    470 /*
    471  * Command to list all variables which are set.  Currently this command
    472  * is invoked from the set command when the set command is called without
    473  * any variables.
    474  */
    475 
    476 int
    477 showvarscmd(argc, argv)
    478 	int argc;
    479 	char **argv;
    480 {
    481 	struct var **vpp;
    482 	struct var *vp;
    483 
    484 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
    485 		for (vp = *vpp ; vp ; vp = vp->next) {
    486 			if ((vp->flags & VUNSET) == 0)
    487 				out1fmt("%s\n", vp->text);
    488 		}
    489 	}
    490 	return 0;
    491 }
    492 
    493 
    494 
    495 /*
    496  * The export and readonly commands.
    497  */
    498 
    499 int
    500 exportcmd(argc, argv)
    501 	int argc;
    502 	char **argv;
    503 {
    504 	struct var **vpp;
    505 	struct var *vp;
    506 	char *name;
    507 	const char *p;
    508 	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
    509 	int pflag;
    510 
    511 	listsetvar(cmdenviron);
    512 	pflag = (nextopt("p") == 'p');
    513 	if (argc > 1 && !pflag) {
    514 		while ((name = *argptr++) != NULL) {
    515 			if ((p = strchr(name, '=')) != NULL) {
    516 				p++;
    517 			} else {
    518 				vpp = hashvar(name);
    519 				for (vp = *vpp ; vp ; vp = vp->next) {
    520 					if (varequal(vp->text, name)) {
    521 						vp->flags |= flag;
    522 						goto found;
    523 					}
    524 				}
    525 			}
    526 			setvar(name, p, flag);
    527 found:;
    528 		}
    529 	} else {
    530 		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
    531 			for (vp = *vpp ; vp ; vp = vp->next) {
    532 				if ((vp->flags & flag) == 0)
    533 					continue;
    534 				if (pflag) {
    535 					out1fmt("%s %s\n", argv[0], vp->text);
    536 				} else {
    537 					for (p = vp->text ; *p != '=' ; p++)
    538 						out1c(*p);
    539 					out1c('\n');
    540 				}
    541 			}
    542 		}
    543 	}
    544 	return 0;
    545 }
    546 
    547 
    548 /*
    549  * The "local" command.
    550  */
    551 
    552 int
    553 localcmd(argc, argv)
    554 	int argc;
    555 	char **argv;
    556 {
    557 	char *name;
    558 
    559 	if (! in_function())
    560 		error("Not in a function");
    561 	while ((name = *argptr++) != NULL) {
    562 		mklocal(name, 0);
    563 	}
    564 	return 0;
    565 }
    566 
    567 
    568 /*
    569  * Make a variable a local variable.  When a variable is made local, it's
    570  * value and flags are saved in a localvar structure.  The saved values
    571  * will be restored when the shell function returns.  We handle the name
    572  * "-" as a special case.
    573  */
    574 
    575 void
    576 mklocal(name, flags)
    577 	char *name;
    578 	{
    579 	struct localvar *lvp;
    580 	struct var **vpp;
    581 	struct var *vp;
    582 
    583 	INTOFF;
    584 	lvp = ckmalloc(sizeof (struct localvar));
    585 	if (name[0] == '-' && name[1] == '\0') {
    586 		char *p;
    587 		p = ckmalloc(sizeof optlist);
    588 		lvp->text = memcpy(p, optlist, sizeof optlist);
    589 		vp = NULL;
    590 	} else {
    591 		vpp = hashvar(name);
    592 		for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next);
    593 		if (vp == NULL) {
    594 			if (strchr(name, '='))
    595 				setvareq(savestr(name), VSTRFIXED|flags);
    596 			else
    597 				setvar(name, NULL, VSTRFIXED|flags);
    598 			vp = *vpp;	/* the new variable */
    599 			lvp->text = NULL;
    600 			lvp->flags = VUNSET;
    601 		} else {
    602 			lvp->text = vp->text;
    603 			lvp->flags = vp->flags;
    604 			vp->flags |= VSTRFIXED|VTEXTFIXED;
    605 			if (strchr(name, '='))
    606 				setvareq(savestr(name), flags);
    607 		}
    608 	}
    609 	lvp->vp = vp;
    610 	lvp->next = localvars;
    611 	localvars = lvp;
    612 	INTON;
    613 }
    614 
    615 
    616 /*
    617  * Called after a function returns.
    618  */
    619 
    620 void
    621 poplocalvars() {
    622 	struct localvar *lvp;
    623 	struct var *vp;
    624 
    625 	while ((lvp = localvars) != NULL) {
    626 		localvars = lvp->next;
    627 		vp = lvp->vp;
    628 		if (vp == NULL) {	/* $- saved */
    629 			memcpy(optlist, lvp->text, sizeof optlist);
    630 			ckfree(lvp->text);
    631 		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
    632 			(void)unsetvar(vp->text);
    633 		} else {
    634 			if ((vp->flags & VTEXTFIXED) == 0)
    635 				ckfree(vp->text);
    636 			vp->flags = lvp->flags;
    637 			vp->text = lvp->text;
    638 		}
    639 		ckfree(lvp);
    640 	}
    641 }
    642 
    643 
    644 int
    645 setvarcmd(argc, argv)
    646 	int argc;
    647 	char **argv;
    648 {
    649 	if (argc <= 2)
    650 		return unsetcmd(argc, argv);
    651 	else if (argc == 3)
    652 		setvar(argv[1], argv[2], 0);
    653 	else
    654 		error("List assignment not implemented");
    655 	return 0;
    656 }
    657 
    658 
    659 /*
    660  * The unset builtin command.  We unset the function before we unset the
    661  * variable to allow a function to be unset when there is a readonly variable
    662  * with the same name.
    663  */
    664 
    665 int
    666 unsetcmd(argc, argv)
    667 	int argc;
    668 	char **argv;
    669 {
    670 	char **ap;
    671 	int i;
    672 	int flg_func = 0;
    673 	int flg_var = 0;
    674 	int ret = 0;
    675 
    676 	while ((i = nextopt("vf")) != '\0') {
    677 		if (i == 'f')
    678 			flg_func = 1;
    679 		else
    680 			flg_var = 1;
    681 	}
    682 	if (flg_func == 0 && flg_var == 0)
    683 		flg_var = 1;
    684 
    685 	for (ap = argptr; *ap ; ap++) {
    686 		if (flg_func)
    687 			ret |= unsetfunc(*ap);
    688 		if (flg_var)
    689 			ret |= unsetvar(*ap);
    690 	}
    691 	return ret;
    692 }
    693 
    694 
    695 /*
    696  * Unset the specified variable.
    697  */
    698 
    699 int
    700 unsetvar(s)
    701 	const char *s;
    702 	{
    703 	struct var **vpp;
    704 	struct var *vp;
    705 
    706 	vpp = hashvar(s);
    707 	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
    708 		if (varequal(vp->text, s)) {
    709 			if (vp->flags & VREADONLY)
    710 				return (1);
    711 			INTOFF;
    712 			if (*(strchr(vp->text, '=') + 1) != '\0')
    713 				setvar(s, nullstr, 0);
    714 			vp->flags &= ~VEXPORT;
    715 			vp->flags |= VUNSET;
    716 			if ((vp->flags & VSTRFIXED) == 0) {
    717 				if ((vp->flags & VTEXTFIXED) == 0)
    718 					ckfree(vp->text);
    719 				*vpp = vp->next;
    720 				ckfree(vp);
    721 			}
    722 			INTON;
    723 			return (0);
    724 		}
    725 	}
    726 
    727 	return (1);
    728 }
    729 
    730 
    731 
    732 /*
    733  * Find the appropriate entry in the hash table from the name.
    734  */
    735 
    736 STATIC struct var **
    737 hashvar(p)
    738 	const char *p;
    739 	{
    740 	unsigned int hashval;
    741 
    742 	hashval = ((unsigned char) *p) << 4;
    743 	while (*p && *p != '=')
    744 		hashval += (unsigned char) *p++;
    745 	return &vartab[hashval % VTABSIZE];
    746 }
    747 
    748 
    749 
    750 /*
    751  * Returns true if the two strings specify the same varable.  The first
    752  * variable name is terminated by '='; the second may be terminated by
    753  * either '=' or '\0'.
    754  */
    755 
    756 STATIC int
    757 varequal(p, q)
    758 	const char *p, *q;
    759 	{
    760 	while (*p == *q++) {
    761 		if (*p++ == '=')
    762 			return 1;
    763 	}
    764 	if (*p == '=' && *(q - 1) == '\0')
    765 		return 1;
    766 	return 0;
    767 }
    768