var.c revision 292664 
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
35static char sccsid[] = "@(#)var.c	8.3 (Berkeley) 5/4/95";
36#endif
37#endif /* not lint */
38#include <sys/cdefs.h>
39__FBSDID("$FreeBSD: stable/10/bin/sh/var.c 292664 2015-12-23 18:24:40Z jilles $");
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#include <langinfo.h>
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 "builtins.h"
67#ifndef NO_HISTORY
68#include "myhistedit.h"
69#endif
70
71
72#define VTABSIZE 39
73
74
75struct varinit {
76	struct var *var;
77	int flags;
78	const char *text;
79	void (*func)(const char *);
80};
81
82
83#ifndef NO_HISTORY
84struct var vhistsize;
85struct var vterm;
86#endif
87struct var vifs;
88struct var vmail;
89struct var vmpath;
90struct var vpath;
91struct var vps1;
92struct var vps2;
93struct var vps4;
94static struct var voptind;
95struct var vdisvfork;
96
97int forcelocal;
98
99static 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	/*
113	 * vps1 depends on uid
114	 */
115	{ &vps2,	0,				"PS2=> ",
116	  NULL },
117	{ &vps4,	0,				"PS4=+ ",
118	  NULL },
119#ifndef NO_HISTORY
120	{ &vterm,	VUNSET,				"TERM=",
121	  setterm },
122#endif
123	{ &voptind,	0,				"OPTIND=1",
124	  getoptsreset },
125	{ &vdisvfork,	VUNSET,				"SH_DISABLE_VFORK=",
126	  NULL },
127	{ NULL,	0,				NULL,
128	  NULL }
129};
130
131static struct var *vartab[VTABSIZE];
132
133static const char *const locale_names[7] = {
134	"LC_COLLATE", "LC_CTYPE", "LC_MONETARY",
135	"LC_NUMERIC", "LC_TIME", "LC_MESSAGES", NULL
136};
137static const int locale_categories[7] = {
138	LC_COLLATE, LC_CTYPE, LC_MONETARY, LC_NUMERIC, LC_TIME, LC_MESSAGES, 0
139};
140
141static int varequal(const char *, const char *);
142static struct var *find_var(const char *, struct var ***, int *);
143static int localevar(const char *);
144
145extern char **environ;
146
147/*
148 * This routine initializes the builtin variables and imports the environment.
149 * It is called when the shell is initialized.
150 */
151
152void
153initvar(void)
154{
155	char ppid[20];
156	const struct varinit *ip;
157	struct var *vp;
158	struct var **vpp;
159	char **envp;
160
161	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
162		if (find_var(ip->text, &vpp, &vp->name_len) != NULL)
163			continue;
164		vp->next = *vpp;
165		*vpp = vp;
166		vp->text = __DECONST(char *, ip->text);
167		vp->flags = ip->flags | VSTRFIXED | VTEXTFIXED;
168		vp->func = ip->func;
169	}
170	/*
171	 * PS1 depends on uid
172	 */
173	if (find_var("PS1", &vpp, &vps1.name_len) == NULL) {
174		vps1.next = *vpp;
175		*vpp = &vps1;
176		vps1.text = __DECONST(char *, geteuid() ? "PS1=$ " : "PS1=# ");
177		vps1.flags = VSTRFIXED|VTEXTFIXED;
178	}
179	fmtstr(ppid, sizeof(ppid), "%d", (int)getppid());
180	setvarsafe("PPID", ppid, 0);
181	for (envp = environ ; *envp ; envp++) {
182		if (strchr(*envp, '=')) {
183			setvareq(*envp, VEXPORT|VTEXTFIXED);
184		}
185	}
186	setvareq("OPTIND=1", VTEXTFIXED);
187}
188
189/*
190 * Safe version of setvar, returns 1 on success 0 on failure.
191 */
192
193int
194setvarsafe(const char *name, const char *val, int flags)
195{
196	struct jmploc jmploc;
197	struct jmploc *const savehandler = handler;
198	int err = 0;
199	int inton;
200
201	inton = is_int_on();
202	if (setjmp(jmploc.loc))
203		err = 1;
204	else {
205		handler = &jmploc;
206		setvar(name, val, flags);
207	}
208	handler = savehandler;
209	SETINTON(inton);
210	return err;
211}
212
213/*
214 * Set the value of a variable.  The flags argument is stored with the
215 * flags of the variable.  If val is NULL, the variable is unset.
216 */
217
218void
219setvar(const char *name, const char *val, int flags)
220{
221	const char *p;
222	size_t len;
223	size_t namelen;
224	size_t vallen;
225	char *nameeq;
226	int isbad;
227
228	isbad = 0;
229	p = name;
230	if (! is_name(*p))
231		isbad = 1;
232	p++;
233	for (;;) {
234		if (! is_in_name(*p)) {
235			if (*p == '\0' || *p == '=')
236				break;
237			isbad = 1;
238		}
239		p++;
240	}
241	namelen = p - name;
242	if (isbad)
243		error("%.*s: bad variable name", (int)namelen, name);
244	len = namelen + 2;		/* 2 is space for '=' and '\0' */
245	if (val == NULL) {
246		flags |= VUNSET;
247		vallen = 0;
248	} else {
249		vallen = strlen(val);
250		len += vallen;
251	}
252	INTOFF;
253	nameeq = ckmalloc(len);
254	memcpy(nameeq, name, namelen);
255	nameeq[namelen] = '=';
256	if (val)
257		memcpy(nameeq + namelen + 1, val, vallen + 1);
258	else
259		nameeq[namelen + 1] = '\0';
260	setvareq(nameeq, flags);
261	INTON;
262}
263
264static int
265localevar(const char *s)
266{
267	const char *const *ss;
268
269	if (*s != 'L')
270		return 0;
271	if (varequal(s + 1, "ANG"))
272		return 1;
273	if (strncmp(s + 1, "C_", 2) != 0)
274		return 0;
275	if (varequal(s + 3, "ALL"))
276		return 1;
277	for (ss = locale_names; *ss ; ss++)
278		if (varequal(s + 3, *ss + 3))
279			return 1;
280	return 0;
281}
282
283
284/*
285 * Sets/unsets an environment variable from a pointer that may actually be a
286 * pointer into environ where the string should not be manipulated.
287 */
288static void
289change_env(const char *s, int set)
290{
291	char *eqp;
292	char *ss;
293
294	INTOFF;
295	ss = savestr(s);
296	if ((eqp = strchr(ss, '=')) != NULL)
297		*eqp = '\0';
298	if (set && eqp != NULL)
299		(void) setenv(ss, eqp + 1, 1);
300	else
301		(void) unsetenv(ss);
302	ckfree(ss);
303	INTON;
304
305	return;
306}
307
308
309/*
310 * Same as setvar except that the variable and value are passed in
311 * the first argument as name=value.  Since the first argument will
312 * be actually stored in the table, it should not be a string that
313 * will go away.
314 */
315
316void
317setvareq(char *s, int flags)
318{
319	struct var *vp, **vpp;
320	int nlen;
321
322	if (aflag)
323		flags |= VEXPORT;
324	if (forcelocal && !(flags & (VNOSET | VNOLOCAL)))
325		mklocal(s);
326	vp = find_var(s, &vpp, &nlen);
327	if (vp != NULL) {
328		if (vp->flags & VREADONLY) {
329			if ((flags & (VTEXTFIXED|VSTACK)) == 0)
330				ckfree(s);
331			error("%.*s: is read only", vp->name_len, vp->text);
332		}
333		if (flags & VNOSET) {
334			if ((flags & (VTEXTFIXED|VSTACK)) == 0)
335				ckfree(s);
336			return;
337		}
338		INTOFF;
339
340		if (vp->func && (flags & VNOFUNC) == 0)
341			(*vp->func)(s + vp->name_len + 1);
342
343		if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
344			ckfree(vp->text);
345
346		vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
347		vp->flags |= flags;
348		vp->text = s;
349
350		/*
351		 * We could roll this to a function, to handle it as
352		 * a regular variable function callback, but why bother?
353		 *
354		 * Note: this assumes iflag is not set to 1 initially.
355		 * As part of initvar(), this is called before arguments
356		 * are looked at.
357		 */
358		if ((vp == &vmpath || (vp == &vmail && ! mpathset())) &&
359		    iflag == 1)
360			chkmail(1);
361		if ((vp->flags & VEXPORT) && localevar(s)) {
362			change_env(s, 1);
363			(void) setlocale(LC_ALL, "");
364			updatecharset();
365		}
366		INTON;
367		return;
368	}
369	/* not found */
370	if (flags & VNOSET) {
371		if ((flags & (VTEXTFIXED|VSTACK)) == 0)
372			ckfree(s);
373		return;
374	}
375	INTOFF;
376	vp = ckmalloc(sizeof (*vp));
377	vp->flags = flags;
378	vp->text = s;
379	vp->name_len = nlen;
380	vp->next = *vpp;
381	vp->func = NULL;
382	*vpp = vp;
383	if ((vp->flags & VEXPORT) && localevar(s)) {
384		change_env(s, 1);
385		(void) setlocale(LC_ALL, "");
386		updatecharset();
387	}
388	INTON;
389}
390
391
392
393/*
394 * Process a linked list of variable assignments.
395 */
396
397void
398listsetvar(struct strlist *list, int flags)
399{
400	struct strlist *lp;
401
402	INTOFF;
403	for (lp = list ; lp ; lp = lp->next) {
404		setvareq(savestr(lp->text), flags);
405	}
406	INTON;
407}
408
409
410
411/*
412 * Find the value of a variable.  Returns NULL if not set.
413 */
414
415char *
416lookupvar(const char *name)
417{
418	struct var *v;
419
420	v = find_var(name, NULL, NULL);
421	if (v == NULL || v->flags & VUNSET)
422		return NULL;
423	return v->text + v->name_len + 1;
424}
425
426
427
428/*
429 * Search the environment of a builtin command.  If the second argument
430 * is nonzero, return the value of a variable even if it hasn't been
431 * exported.
432 */
433
434char *
435bltinlookup(const char *name, int doall)
436{
437	struct strlist *sp;
438	struct var *v;
439	char *result;
440
441	result = NULL;
442	for (sp = cmdenviron ; sp ; sp = sp->next) {
443		if (varequal(sp->text, name))
444			result = strchr(sp->text, '=') + 1;
445	}
446	if (result != NULL)
447		return result;
448
449	v = find_var(name, NULL, NULL);
450	if (v == NULL || v->flags & VUNSET ||
451	    (!doall && (v->flags & VEXPORT) == 0))
452		return NULL;
453	return v->text + v->name_len + 1;
454}
455
456
457/*
458 * Set up locale for a builtin (LANG/LC_* assignments).
459 */
460void
461bltinsetlocale(void)
462{
463	struct strlist *lp;
464	int act = 0;
465	char *loc, *locdef;
466	int i;
467
468	for (lp = cmdenviron ; lp ; lp = lp->next) {
469		if (localevar(lp->text)) {
470			act = 1;
471			break;
472		}
473	}
474	if (!act)
475		return;
476	loc = bltinlookup("LC_ALL", 0);
477	INTOFF;
478	if (loc != NULL) {
479		setlocale(LC_ALL, loc);
480		INTON;
481		updatecharset();
482		return;
483	}
484	locdef = bltinlookup("LANG", 0);
485	for (i = 0; locale_names[i] != NULL; i++) {
486		loc = bltinlookup(locale_names[i], 0);
487		if (loc == NULL)
488			loc = locdef;
489		if (loc != NULL)
490			setlocale(locale_categories[i], loc);
491	}
492	INTON;
493	updatecharset();
494}
495
496/*
497 * Undo the effect of bltinlocaleset().
498 */
499void
500bltinunsetlocale(void)
501{
502	struct strlist *lp;
503
504	INTOFF;
505	for (lp = cmdenviron ; lp ; lp = lp->next) {
506		if (localevar(lp->text)) {
507			setlocale(LC_ALL, "");
508			updatecharset();
509			return;
510		}
511	}
512	INTON;
513}
514
515/*
516 * Update the localeisutf8 flag.
517 */
518void
519updatecharset(void)
520{
521	char *charset;
522
523	charset = nl_langinfo(CODESET);
524	localeisutf8 = !strcmp(charset, "UTF-8");
525}
526
527void
528initcharset(void)
529{
530	updatecharset();
531	initial_localeisutf8 = localeisutf8;
532}
533
534/*
535 * Generate a list of exported variables.  This routine is used to construct
536 * the third argument to execve when executing a program.
537 */
538
539char **
540environment(void)
541{
542	int nenv;
543	struct var **vpp;
544	struct var *vp;
545	char **env, **ep;
546
547	nenv = 0;
548	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
549		for (vp = *vpp ; vp ; vp = vp->next)
550			if (vp->flags & VEXPORT)
551				nenv++;
552	}
553	ep = env = stalloc((nenv + 1) * sizeof *env);
554	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
555		for (vp = *vpp ; vp ; vp = vp->next)
556			if (vp->flags & VEXPORT)
557				*ep++ = vp->text;
558	}
559	*ep = NULL;
560	return env;
561}
562
563
564static int
565var_compare(const void *a, const void *b)
566{
567	const char *const *sa, *const *sb;
568
569	sa = a;
570	sb = b;
571	/*
572	 * This compares two var=value strings which creates a different
573	 * order from what you would probably expect.  POSIX is somewhat
574	 * ambiguous on what should be sorted exactly.
575	 */
576	return strcoll(*sa, *sb);
577}
578
579
580/*
581 * Command to list all variables which are set.  This is invoked from the
582 * set command when it is called without any options or operands.
583 */
584
585int
586showvarscmd(int argc __unused, char **argv __unused)
587{
588	struct var **vpp;
589	struct var *vp;
590	const char *s;
591	const char **vars;
592	int i, n;
593
594	/*
595	 * POSIX requires us to sort the variables.
596	 */
597	n = 0;
598	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
599		for (vp = *vpp; vp; vp = vp->next) {
600			if (!(vp->flags & VUNSET))
601				n++;
602		}
603	}
604
605	INTOFF;
606	vars = ckmalloc(n * sizeof(*vars));
607	i = 0;
608	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
609		for (vp = *vpp; vp; vp = vp->next) {
610			if (!(vp->flags & VUNSET))
611				vars[i++] = vp->text;
612		}
613	}
614
615	qsort(vars, n, sizeof(*vars), var_compare);
616	for (i = 0; i < n; i++) {
617		/*
618		 * Skip improper variable names so the output remains usable as
619		 * shell input.
620		 */
621		if (!isassignment(vars[i]))
622			continue;
623		s = strchr(vars[i], '=');
624		s++;
625		outbin(vars[i], s - vars[i], out1);
626		out1qstr(s);
627		out1c('\n');
628	}
629	ckfree(vars);
630	INTON;
631
632	return 0;
633}
634
635
636
637/*
638 * The export and readonly commands.
639 */
640
641int
642exportcmd(int argc __unused, char **argv)
643{
644	struct var **vpp;
645	struct var *vp;
646	char **ap;
647	char *name;
648	char *p;
649	char *cmdname;
650	int ch, values;
651	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
652
653	cmdname = argv[0];
654	values = 0;
655	while ((ch = nextopt("p")) != '\0') {
656		switch (ch) {
657		case 'p':
658			values = 1;
659			break;
660		}
661	}
662
663	if (values && *argptr != NULL)
664		error("-p requires no arguments");
665	if (*argptr != NULL) {
666		for (ap = argptr; (name = *ap) != NULL; ap++) {
667			if ((p = strchr(name, '=')) != NULL) {
668				p++;
669			} else {
670				vp = find_var(name, NULL, NULL);
671				if (vp != NULL) {
672					vp->flags |= flag;
673					if ((vp->flags & VEXPORT) && localevar(vp->text)) {
674						change_env(vp->text, 1);
675						(void) setlocale(LC_ALL, "");
676						updatecharset();
677					}
678					continue;
679				}
680			}
681			setvar(name, p, flag);
682		}
683	} else {
684		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
685			for (vp = *vpp ; vp ; vp = vp->next) {
686				if (vp->flags & flag) {
687					if (values) {
688						/*
689						 * Skip improper variable names
690						 * so the output remains usable
691						 * as shell input.
692						 */
693						if (!isassignment(vp->text))
694							continue;
695						out1str(cmdname);
696						out1c(' ');
697					}
698					if (values && !(vp->flags & VUNSET)) {
699						outbin(vp->text,
700						    vp->name_len + 1, out1);
701						out1qstr(vp->text +
702						    vp->name_len + 1);
703					} else
704						outbin(vp->text, vp->name_len,
705						    out1);
706					out1c('\n');
707				}
708			}
709		}
710	}
711	return 0;
712}
713
714
715/*
716 * The "local" command.
717 */
718
719int
720localcmd(int argc __unused, char **argv __unused)
721{
722	char *name;
723
724	nextopt("");
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
741void
742mklocal(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
783void
784poplocalvars(void)
785{
786	struct localvar *lvp;
787	struct var *vp;
788
789	INTOFF;
790	while ((lvp = localvars) != NULL) {
791		localvars = lvp->next;
792		vp = lvp->vp;
793		if (vp == NULL) {	/* $- saved */
794			memcpy(optlist, lvp->text, sizeof optlist);
795			ckfree(lvp->text);
796			optschanged();
797		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
798			(void)unsetvar(vp->text);
799		} else {
800			if ((vp->flags & VTEXTFIXED) == 0)
801				ckfree(vp->text);
802			vp->flags = lvp->flags;
803			vp->text = lvp->text;
804		}
805		ckfree(lvp);
806	}
807	INTON;
808}
809
810
811int
812setvarcmd(int argc, char **argv)
813{
814	if (argc <= 2)
815		return unsetcmd(argc, argv);
816	else if (argc == 3)
817		setvar(argv[1], argv[2], 0);
818	else
819		error("too many arguments");
820	return 0;
821}
822
823
824/*
825 * The unset builtin command.
826 */
827
828int
829unsetcmd(int argc __unused, char **argv __unused)
830{
831	char **ap;
832	int i;
833	int flg_func = 0;
834	int flg_var = 0;
835	int ret = 0;
836
837	while ((i = nextopt("vf")) != '\0') {
838		if (i == 'f')
839			flg_func = 1;
840		else
841			flg_var = 1;
842	}
843	if (flg_func == 0 && flg_var == 0)
844		flg_var = 1;
845
846	INTOFF;
847	for (ap = argptr; *ap ; ap++) {
848		if (flg_func)
849			ret |= unsetfunc(*ap);
850		if (flg_var)
851			ret |= unsetvar(*ap);
852	}
853	INTON;
854	return ret;
855}
856
857
858/*
859 * Unset the specified variable.
860 * Called with interrupts off.
861 */
862
863int
864unsetvar(const char *s)
865{
866	struct var **vpp;
867	struct var *vp;
868
869	vp = find_var(s, &vpp, NULL);
870	if (vp == NULL)
871		return (0);
872	if (vp->flags & VREADONLY)
873		return (1);
874	if (vp->text[vp->name_len + 1] != '\0')
875		setvar(s, nullstr, 0);
876	if ((vp->flags & VEXPORT) && localevar(vp->text)) {
877		change_env(s, 0);
878		setlocale(LC_ALL, "");
879		updatecharset();
880	}
881	vp->flags &= ~VEXPORT;
882	vp->flags |= VUNSET;
883	if ((vp->flags & VSTRFIXED) == 0) {
884		if ((vp->flags & VTEXTFIXED) == 0)
885			ckfree(vp->text);
886		*vpp = vp->next;
887		ckfree(vp);
888	}
889	return (0);
890}
891
892
893
894/*
895 * Returns true if the two strings specify the same variable.  The first
896 * variable name is terminated by '='; the second may be terminated by
897 * either '=' or '\0'.
898 */
899
900static int
901varequal(const char *p, const char *q)
902{
903	while (*p == *q++) {
904		if (*p++ == '=')
905			return 1;
906	}
907	if (*p == '=' && *(q - 1) == '\0')
908		return 1;
909	return 0;
910}
911
912/*
913 * Search for a variable.
914 * 'name' may be terminated by '=' or a NUL.
915 * vppp is set to the pointer to vp, or the list head if vp isn't found
916 * lenp is set to the number of characters in 'name'
917 */
918
919static struct var *
920find_var(const char *name, struct var ***vppp, int *lenp)
921{
922	unsigned int hashval;
923	int len;
924	struct var *vp, **vpp;
925	const char *p = name;
926
927	hashval = 0;
928	while (*p && *p != '=')
929		hashval = 2 * hashval + (unsigned char)*p++;
930	len = p - name;
931
932	if (lenp)
933		*lenp = len;
934	vpp = &vartab[hashval % VTABSIZE];
935	if (vppp)
936		*vppp = vpp;
937
938	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
939		if (vp->name_len != len)
940			continue;
941		if (memcmp(vp->text, name, len) != 0)
942			continue;
943		if (vppp)
944			*vppp = vpp;
945		return vp;
946	}
947	return NULL;
948}
949