xref: /freebsd/bin/sh/var.c (revision 941e286383714ef25f1ffe9ba6ae5040afdd7060) 
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 
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 #ifndef NO_HISTORY
66 #include "myhistedit.h"
67 #endif
68 
69 
70 #define VTABSIZE 39
71 
72 
73 struct varinit {
74 	struct var *var;
75 	int flags;
76 	const char *text;
77 	void (*func)(const char *);
78 };
79 
80 
81 #ifndef NO_HISTORY
82 struct var vhistsize;
83 #endif
84 struct var vifs;
85 struct var vmail;
86 struct var vmpath;
87 struct var vpath;
88 struct var vppid;
89 struct var vps1;
90 struct var vps2;
91 struct var vps4;
92 struct var vvers;
93 STATIC struct var voptind;
94 
95 STATIC const struct varinit varinit[] = {
96 #ifndef NO_HISTORY
97 	{ &vhistsize,	VUNSET,				"HISTSIZE=",
98 	  sethistsize },
99 #endif
100 	{ &vifs,	0,				"IFS= \t\n",
101 	  NULL },
102 	{ &vmail,	VUNSET,				"MAIL=",
103 	  NULL },
104 	{ &vmpath,	VUNSET,				"MAILPATH=",
105 	  NULL },
106 	{ &vpath,	0,				"PATH=" _PATH_DEFPATH,
107 	  changepath },
108 	{ &vppid,	VUNSET,				"PPID=",
109 	  NULL },
110 	/*
111 	 * vps1 depends on uid
112 	 */
113 	{ &vps2,	0,				"PS2=> ",
114 	  NULL },
115 	{ &vps4,	0,				"PS4=+ ",
116 	  NULL },
117 	{ &voptind,	0,				"OPTIND=1",
118 	  getoptsreset },
119 	{ NULL,	0,				NULL,
120 	  NULL }
121 };
122 
123 STATIC struct var *vartab[VTABSIZE];
124 
125 STATIC struct var **hashvar(const char *);
126 STATIC int varequal(const char *, const char *);
127 STATIC int localevar(const char *);
128 
129 /*
130  * Initialize the variable symbol tables and import the environment.
131  */
132 
133 #ifdef mkinit
134 INCLUDE "var.h"
135 MKINIT char **environ;
136 INIT {
137 	char **envp;
138 
139 	initvar();
140 	for (envp = environ ; *envp ; envp++) {
141 		if (strchr(*envp, '=')) {
142 			setvareq(*envp, VEXPORT|VTEXTFIXED);
143 		}
144 	}
145 }
146 #endif
147 
148 
149 /*
150  * This routine initializes the builtin variables.  It is called when the
151  * shell is initialized and again when a shell procedure is spawned.
152  */
153 
154 void
155 initvar(void)
156 {
157 	char ppid[20];
158 	const struct varinit *ip;
159 	struct var *vp;
160 	struct var **vpp;
161 
162 	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
163 		if ((vp->flags & VEXPORT) == 0) {
164 			vpp = hashvar(ip->text);
165 			vp->next = *vpp;
166 			*vpp = vp;
167 			vp->text = __DECONST(char *, ip->text);
168 			vp->flags = ip->flags | VSTRFIXED | VTEXTFIXED;
169 			vp->func = ip->func;
170 		}
171 	}
172 	/*
173 	 * PS1 depends on uid
174 	 */
175 	if ((vps1.flags & VEXPORT) == 0) {
176 		vpp = hashvar("PS1=");
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 }
187 
188 /*
189  * Safe version of setvar, returns 1 on success 0 on failure.
190  */
191 
192 int
193 setvarsafe(const char *name, const char *val, int flags)
194 {
195 	struct jmploc jmploc;
196 	struct jmploc *const savehandler = handler;
197 	int err = 0;
198 	int inton;
199 
200 	inton = is_int_on();
201 	if (setjmp(jmploc.loc))
202 		err = 1;
203 	else {
204 		handler = &jmploc;
205 		setvar(name, val, flags);
206 	}
207 	handler = savehandler;
208 	SETINTON(inton);
209 	return err;
210 }
211 
212 /*
213  * Set the value of a variable.  The flags argument is stored with the
214  * flags of the variable.  If val is NULL, the variable is unset.
215  */
216 
217 void
218 setvar(const char *name, const char *val, int flags)
219 {
220 	const char *p;
221 	int len;
222 	int namelen;
223 	char *nameeq;
224 	int isbad;
225 
226 	isbad = 0;
227 	p = name;
228 	if (! is_name(*p))
229 		isbad = 1;
230 	p++;
231 	for (;;) {
232 		if (! is_in_name(*p)) {
233 			if (*p == '\0' || *p == '=')
234 				break;
235 			isbad = 1;
236 		}
237 		p++;
238 	}
239 	namelen = p - name;
240 	if (isbad)
241 		error("%.*s: bad variable name", namelen, name);
242 	len = namelen + 2;		/* 2 is space for '=' and '\0' */
243 	if (val == NULL) {
244 		flags |= VUNSET;
245 	} else {
246 		len += strlen(val);
247 	}
248 	nameeq = ckmalloc(len);
249 	memcpy(nameeq, name, namelen);
250 	nameeq[namelen] = '=';
251 	if (val)
252 		scopy(val, nameeq + namelen + 1);
253 	else
254 		nameeq[namelen + 1] = '\0';
255 	setvareq(nameeq, flags);
256 }
257 
258 STATIC int
259 localevar(const char *s)
260 {
261 	static const char *lnames[7] = {
262 		"ALL", "COLLATE", "CTYPE", "MONETARY",
263 		"NUMERIC", "TIME", NULL
264 	};
265 	const char **ss;
266 
267 	if (*s != 'L')
268 		return 0;
269 	if (varequal(s + 1, "ANG"))
270 		return 1;
271 	if (strncmp(s + 1, "C_", 2) != 0)
272 		return 0;
273 	for (ss = lnames; *ss ; ss++)
274 		if (varequal(s + 3, *ss))
275 			return 1;
276 	return 0;
277 }
278 
279 
280 /*
281  * Sets/unsets an environment variable from a pointer that may actually be a
282  * pointer into environ where the string should not be manipulated.
283  */
284 static void
285 change_env(const char *s, int set)
286 {
287 	char *eqp;
288 	char *ss;
289 
290 	ss = savestr(s);
291 	if ((eqp = strchr(ss, '=')) != NULL)
292 		*eqp = '\0';
293 	if (set && eqp != NULL)
294 		(void) setenv(ss, eqp + 1, 1);
295 	else
296 		(void) unsetenv(ss);
297 	ckfree(ss);
298 
299 	return;
300 }
301 
302 
303 /*
304  * Same as setvar except that the variable and value are passed in
305  * the first argument as name=value.  Since the first argument will
306  * be actually stored in the table, it should not be a string that
307  * will go away.
308  */
309 
310 void
311 setvareq(char *s, int flags)
312 {
313 	struct var *vp, **vpp;
314 	int len;
315 
316 	if (aflag)
317 		flags |= VEXPORT;
318 	vpp = hashvar(s);
319 	for (vp = *vpp ; vp ; vp = vp->next) {
320 		if (varequal(s, vp->text)) {
321 			if (vp->flags & VREADONLY) {
322 				len = strchr(s, '=') - s;
323 				error("%.*s: is read only", len, s);
324 			}
325 			INTOFF;
326 
327 			if (vp->func && (flags & VNOFUNC) == 0)
328 				(*vp->func)(strchr(s, '=') + 1);
329 
330 			if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
331 				ckfree(vp->text);
332 
333 			vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
334 			vp->flags |= flags;
335 			vp->text = s;
336 
337 			/*
338 			 * We could roll this to a function, to handle it as
339 			 * a regular variable function callback, but why bother?
340 			 */
341 			if (vp == &vmpath || (vp == &vmail && ! mpathset()))
342 				chkmail(1);
343 			if ((vp->flags & VEXPORT) && localevar(s)) {
344 				change_env(s, 1);
345 				(void) setlocale(LC_ALL, "");
346 			}
347 			INTON;
348 			return;
349 		}
350 	}
351 	/* not found */
352 	vp = ckmalloc(sizeof (*vp));
353 	vp->flags = flags;
354 	vp->text = s;
355 	vp->next = *vpp;
356 	vp->func = NULL;
357 	INTOFF;
358 	*vpp = vp;
359 	if ((vp->flags & VEXPORT) && localevar(s)) {
360 		change_env(s, 1);
361 		(void) setlocale(LC_ALL, "");
362 	}
363 	INTON;
364 }
365 
366 
367 
368 /*
369  * Process a linked list of variable assignments.
370  */
371 
372 void
373 listsetvar(struct strlist *list)
374 {
375 	struct strlist *lp;
376 
377 	INTOFF;
378 	for (lp = list ; lp ; lp = lp->next) {
379 		setvareq(savestr(lp->text), 0);
380 	}
381 	INTON;
382 }
383 
384 
385 
386 /*
387  * Find the value of a variable.  Returns NULL if not set.
388  */
389 
390 char *
391 lookupvar(const char *name)
392 {
393 	struct var *v;
394 
395 	for (v = *hashvar(name) ; v ; v = v->next) {
396 		if (varequal(v->text, name)) {
397 			if (v->flags & VUNSET)
398 				return NULL;
399 			return strchr(v->text, '=') + 1;
400 		}
401 	}
402 	return NULL;
403 }
404 
405 
406 
407 /*
408  * Search the environment of a builtin command.  If the second argument
409  * is nonzero, return the value of a variable even if it hasn't been
410  * exported.
411  */
412 
413 char *
414 bltinlookup(const char *name, int doall)
415 {
416 	struct strlist *sp;
417 	struct var *v;
418 
419 	for (sp = cmdenviron ; sp ; sp = sp->next) {
420 		if (varequal(sp->text, name))
421 			return strchr(sp->text, '=') + 1;
422 	}
423 	for (v = *hashvar(name) ; v ; v = v->next) {
424 		if (varequal(v->text, name)) {
425 			if ((v->flags & VUNSET)
426 			 || (!doall && (v->flags & VEXPORT) == 0))
427 				return NULL;
428 			return strchr(v->text, '=') + 1;
429 		}
430 	}
431 	return NULL;
432 }
433 
434 
435 
436 /*
437  * Generate a list of exported variables.  This routine is used to construct
438  * the third argument to execve when executing a program.
439  */
440 
441 char **
442 environment(void)
443 {
444 	int nenv;
445 	struct var **vpp;
446 	struct var *vp;
447 	char **env, **ep;
448 
449 	nenv = 0;
450 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
451 		for (vp = *vpp ; vp ; vp = vp->next)
452 			if (vp->flags & VEXPORT)
453 				nenv++;
454 	}
455 	ep = env = stalloc((nenv + 1) * sizeof *env);
456 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
457 		for (vp = *vpp ; vp ; vp = vp->next)
458 			if (vp->flags & VEXPORT)
459 				*ep++ = vp->text;
460 	}
461 	*ep = NULL;
462 	return env;
463 }
464 
465 
466 /*
467  * Called when a shell procedure is invoked to clear out nonexported
468  * variables.  It is also necessary to reallocate variables of with
469  * VSTACK set since these are currently allocated on the stack.
470  */
471 
472 MKINIT void shprocvar(void);
473 
474 #ifdef mkinit
475 SHELLPROC {
476 	shprocvar();
477 }
478 #endif
479 
480 void
481 shprocvar(void)
482 {
483 	struct var **vpp;
484 	struct var *vp, **prev;
485 
486 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
487 		for (prev = vpp ; (vp = *prev) != NULL ; ) {
488 			if ((vp->flags & VEXPORT) == 0) {
489 				*prev = vp->next;
490 				if ((vp->flags & VTEXTFIXED) == 0)
491 					ckfree(vp->text);
492 				if ((vp->flags & VSTRFIXED) == 0)
493 					ckfree(vp);
494 			} else {
495 				if (vp->flags & VSTACK) {
496 					vp->text = savestr(vp->text);
497 					vp->flags &=~ VSTACK;
498 				}
499 				prev = &vp->next;
500 			}
501 		}
502 	}
503 	initvar();
504 }
505 
506 
507 static int
508 var_compare(const void *a, const void *b)
509 {
510 	const char *const *sa, *const *sb;
511 
512 	sa = a;
513 	sb = b;
514 	/*
515 	 * This compares two var=value strings which creates a different
516 	 * order from what you would probably expect.  POSIX is somewhat
517 	 * ambiguous on what should be sorted exactly.
518 	 */
519 	return strcoll(*sa, *sb);
520 }
521 
522 
523 /*
524  * Command to list all variables which are set.  Currently this command
525  * is invoked from the set command when the set command is called without
526  * any variables.
527  */
528 
529 int
530 showvarscmd(int argc __unused, char **argv __unused)
531 {
532 	struct var **vpp;
533 	struct var *vp;
534 	const char *s;
535 	const char **vars;
536 	int i, n;
537 
538 	/*
539 	 * POSIX requires us to sort the variables.
540 	 */
541 	n = 0;
542 	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
543 		for (vp = *vpp; vp; vp = vp->next) {
544 			if (!(vp->flags & VUNSET))
545 				n++;
546 		}
547 	}
548 
549 	INTON;
550 	vars = ckmalloc(n * sizeof(*vars));
551 	i = 0;
552 	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
553 		for (vp = *vpp; vp; vp = vp->next) {
554 			if (!(vp->flags & VUNSET))
555 				vars[i++] = vp->text;
556 		}
557 	}
558 
559 	qsort(vars, n, sizeof(*vars), var_compare);
560 	for (i = 0; i < n; i++) {
561 		for (s = vars[i]; *s != '='; s++)
562 			out1c(*s);
563 		out1c('=');
564 		out1qstr(s + 1);
565 		out1c('\n');
566 	}
567 	ckfree(vars);
568 	INTOFF;
569 
570 	return 0;
571 }
572 
573 
574 
575 /*
576  * The export and readonly commands.
577  */
578 
579 int
580 exportcmd(int argc, char **argv)
581 {
582 	struct var **vpp;
583 	struct var *vp;
584 	char *name;
585 	char *p;
586 	char *cmdname;
587 	int ch, values;
588 	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
589 
590 	cmdname = argv[0];
591 	optreset = optind = 1;
592 	opterr = 0;
593 	values = 0;
594 	while ((ch = getopt(argc, argv, "p")) != -1) {
595 		switch (ch) {
596 		case 'p':
597 			values = 1;
598 			break;
599 		case '?':
600 		default:
601 			error("unknown option: -%c", optopt);
602 		}
603 	}
604 	argc -= optind;
605 	argv += optind;
606 
607 	if (values && argc != 0)
608 		error("-p requires no arguments");
609 	if (argc != 0) {
610 		while ((name = *argv++) != NULL) {
611 			if ((p = strchr(name, '=')) != NULL) {
612 				p++;
613 			} else {
614 				vpp = hashvar(name);
615 				for (vp = *vpp ; vp ; vp = vp->next) {
616 					if (varequal(vp->text, name)) {
617 
618 						vp->flags |= flag;
619 						if ((vp->flags & VEXPORT) && localevar(vp->text)) {
620 							change_env(vp->text, 1);
621 							(void) setlocale(LC_ALL, "");
622 						}
623 						goto found;
624 					}
625 				}
626 			}
627 			setvar(name, p, flag);
628 found:;
629 		}
630 	} else {
631 		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
632 			for (vp = *vpp ; vp ; vp = vp->next) {
633 				if (vp->flags & flag) {
634 					if (values) {
635 						out1str(cmdname);
636 						out1c(' ');
637 					}
638 					for (p = vp->text ; *p != '=' ; p++)
639 						out1c(*p);
640 					if (values && !(vp->flags & VUNSET)) {
641 						out1c('=');
642 						out1qstr(p + 1);
643 					}
644 					out1c('\n');
645 				}
646 			}
647 		}
648 	}
649 	return 0;
650 }
651 
652 
653 /*
654  * The "local" command.
655  */
656 
657 int
658 localcmd(int argc __unused, char **argv __unused)
659 {
660 	char *name;
661 
662 	if (! in_function())
663 		error("Not in a function");
664 	while ((name = *argptr++) != NULL) {
665 		mklocal(name);
666 	}
667 	return 0;
668 }
669 
670 
671 /*
672  * Make a variable a local variable.  When a variable is made local, it's
673  * value and flags are saved in a localvar structure.  The saved values
674  * will be restored when the shell function returns.  We handle the name
675  * "-" as a special case.
676  */
677 
678 void
679 mklocal(char *name)
680 {
681 	struct localvar *lvp;
682 	struct var **vpp;
683 	struct var *vp;
684 
685 	INTOFF;
686 	lvp = ckmalloc(sizeof (struct localvar));
687 	if (name[0] == '-' && name[1] == '\0') {
688 		lvp->text = ckmalloc(sizeof optlist);
689 		memcpy(lvp->text, optlist, sizeof optlist);
690 		vp = NULL;
691 	} else {
692 		vpp = hashvar(name);
693 		for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next);
694 		if (vp == NULL) {
695 			if (strchr(name, '='))
696 				setvareq(savestr(name), VSTRFIXED);
697 			else
698 				setvar(name, NULL, VSTRFIXED);
699 			vp = *vpp;	/* the new variable */
700 			lvp->text = NULL;
701 			lvp->flags = VUNSET;
702 		} else {
703 			lvp->text = vp->text;
704 			lvp->flags = vp->flags;
705 			vp->flags |= VSTRFIXED|VTEXTFIXED;
706 			if (strchr(name, '='))
707 				setvareq(savestr(name), 0);
708 		}
709 	}
710 	lvp->vp = vp;
711 	lvp->next = localvars;
712 	localvars = lvp;
713 	INTON;
714 }
715 
716 
717 /*
718  * Called after a function returns.
719  */
720 
721 void
722 poplocalvars(void)
723 {
724 	struct localvar *lvp;
725 	struct var *vp;
726 
727 	while ((lvp = localvars) != NULL) {
728 		localvars = lvp->next;
729 		vp = lvp->vp;
730 		if (vp == NULL) {	/* $- saved */
731 			memcpy(optlist, lvp->text, sizeof optlist);
732 			ckfree(lvp->text);
733 		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
734 			(void)unsetvar(vp->text);
735 		} else {
736 			if ((vp->flags & VTEXTFIXED) == 0)
737 				ckfree(vp->text);
738 			vp->flags = lvp->flags;
739 			vp->text = lvp->text;
740 		}
741 		ckfree(lvp);
742 	}
743 }
744 
745 
746 int
747 setvarcmd(int argc, char **argv)
748 {
749 	if (argc <= 2)
750 		return unsetcmd(argc, argv);
751 	else if (argc == 3)
752 		setvar(argv[1], argv[2], 0);
753 	else
754 		error("List assignment not implemented");
755 	return 0;
756 }
757 
758 
759 /*
760  * The unset builtin command.  We unset the function before we unset the
761  * variable to allow a function to be unset when there is a readonly variable
762  * with the same name.
763  */
764 
765 int
766 unsetcmd(int argc __unused, char **argv __unused)
767 {
768 	char **ap;
769 	int i;
770 	int flg_func = 0;
771 	int flg_var = 0;
772 	int ret = 0;
773 
774 	while ((i = nextopt("vf")) != '\0') {
775 		if (i == 'f')
776 			flg_func = 1;
777 		else
778 			flg_var = 1;
779 	}
780 	if (flg_func == 0 && flg_var == 0)
781 		flg_var = 1;
782 
783 	for (ap = argptr; *ap ; ap++) {
784 		if (flg_func)
785 			ret |= unsetfunc(*ap);
786 		if (flg_var)
787 			ret |= unsetvar(*ap);
788 	}
789 	return ret;
790 }
791 
792 
793 /*
794  * Unset the specified variable.
795  */
796 
797 int
798 unsetvar(const char *s)
799 {
800 	struct var **vpp;
801 	struct var *vp;
802 
803 	vpp = hashvar(s);
804 	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
805 		if (varequal(vp->text, s)) {
806 			if (vp->flags & VREADONLY)
807 				return (1);
808 			INTOFF;
809 			if (*(strchr(vp->text, '=') + 1) != '\0')
810 				setvar(s, nullstr, 0);
811 			if ((vp->flags & VEXPORT) && localevar(vp->text)) {
812 				change_env(s, 0);
813 				setlocale(LC_ALL, "");
814 			}
815 			vp->flags &= ~VEXPORT;
816 			vp->flags |= VUNSET;
817 			if ((vp->flags & VSTRFIXED) == 0) {
818 				if ((vp->flags & VTEXTFIXED) == 0)
819 					ckfree(vp->text);
820 				*vpp = vp->next;
821 				ckfree(vp);
822 			}
823 			INTON;
824 			return (0);
825 		}
826 	}
827 
828 	return (0);
829 }
830 
831 
832 
833 /*
834  * Find the appropriate entry in the hash table from the name.
835  */
836 
837 STATIC struct var **
838 hashvar(const char *p)
839 {
840 	unsigned int hashval;
841 
842 	hashval = ((unsigned char) *p) << 4;
843 	while (*p && *p != '=')
844 		hashval += (unsigned char) *p++;
845 	return &vartab[hashval % VTABSIZE];
846 }
847 
848 
849 
850 /*
851  * Returns true if the two strings specify the same varable.  The first
852  * variable name is terminated by '='; the second may be terminated by
853  * either '=' or '\0'.
854  */
855 
856 STATIC int
857 varequal(const char *p, const char *q)
858 {
859 	while (*p == *q++) {
860 		if (*p++ == '=')
861 			return 1;
862 	}
863 	if (*p == '=' && *(q - 1) == '\0')
864 		return 1;
865 	return 0;
866 }
867