var.c revision 231001 
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: head/bin/sh/var.c 231001 2012-02-04 23:29:07Z 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 vppid;
92struct var vps1;
93struct var vps2;
94struct var vps4;
95struct var vvers;
96static struct var voptind;
97struct var vdisvfork;
98
99int forcelocal;
100
101static const struct varinit varinit[] = {
102#ifndef NO_HISTORY
103	{ &vhistsize,	VUNSET,				"HISTSIZE=",
104	  sethistsize },
105#endif
106	{ &vifs,	0,				"IFS= \t\n",
107	  NULL },
108	{ &vmail,	VUNSET,				"MAIL=",
109	  NULL },
110	{ &vmpath,	VUNSET,				"MAILPATH=",
111	  NULL },
112	{ &vpath,	0,				"PATH=" _PATH_DEFPATH,
113	  changepath },
114	{ &vppid,	VUNSET,				"PPID=",
115	  NULL },
116	/*
117	 * vps1 depends on uid
118	 */
119	{ &vps2,	0,				"PS2=> ",
120	  NULL },
121	{ &vps4,	0,				"PS4=+ ",
122	  NULL },
123#ifndef NO_HISTORY
124	{ &vterm,	VUNSET,				"TERM=",
125	  setterm },
126#endif
127	{ &voptind,	0,				"OPTIND=1",
128	  getoptsreset },
129	{ &vdisvfork,	VUNSET,				"SH_DISABLE_VFORK=",
130	  NULL },
131	{ NULL,	0,				NULL,
132	  NULL }
133};
134
135static struct var *vartab[VTABSIZE];
136
137static const char *const locale_names[7] = {
138	"LC_COLLATE", "LC_CTYPE", "LC_MONETARY",
139	"LC_NUMERIC", "LC_TIME", "LC_MESSAGES", NULL
140};
141static const int locale_categories[7] = {
142	LC_COLLATE, LC_CTYPE, LC_MONETARY, LC_NUMERIC, LC_TIME, LC_MESSAGES, 0
143};
144
145static int varequal(const char *, const char *);
146static struct var *find_var(const char *, struct var ***, int *);
147static int localevar(const char *);
148
149/*
150 * Initialize the variable symbol tables and import the environment.
151 */
152
153#ifdef mkinit
154INCLUDE "var.h"
155MKINIT char **environ;
156INIT {
157	char **envp;
158
159	initvar();
160	for (envp = environ ; *envp ; envp++) {
161		if (strchr(*envp, '=')) {
162			setvareq(*envp, VEXPORT|VTEXTFIXED);
163		}
164	}
165}
166#endif
167
168
169/*
170 * This routine initializes the builtin variables.  It is called when the
171 * shell is initialized.
172 */
173
174void
175initvar(void)
176{
177	char ppid[20];
178	const struct varinit *ip;
179	struct var *vp;
180	struct var **vpp;
181
182	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
183		if (find_var(ip->text, &vpp, &vp->name_len) != NULL)
184			continue;
185		vp->next = *vpp;
186		*vpp = vp;
187		vp->text = __DECONST(char *, ip->text);
188		vp->flags = ip->flags | VSTRFIXED | VTEXTFIXED;
189		vp->func = ip->func;
190	}
191	/*
192	 * PS1 depends on uid
193	 */
194	if (find_var("PS1", &vpp, &vps1.name_len) == NULL) {
195		vps1.next = *vpp;
196		*vpp = &vps1;
197		vps1.text = __DECONST(char *, geteuid() ? "PS1=$ " : "PS1=# ");
198		vps1.flags = VSTRFIXED|VTEXTFIXED;
199	}
200	if ((vppid.flags & VEXPORT) == 0) {
201		fmtstr(ppid, sizeof(ppid), "%d", (int)getppid());
202		setvarsafe("PPID", ppid, 0);
203	}
204}
205
206/*
207 * Safe version of setvar, returns 1 on success 0 on failure.
208 */
209
210int
211setvarsafe(const char *name, const char *val, int flags)
212{
213	struct jmploc jmploc;
214	struct jmploc *const savehandler = handler;
215	int err = 0;
216	int inton;
217
218	inton = is_int_on();
219	if (setjmp(jmploc.loc))
220		err = 1;
221	else {
222		handler = &jmploc;
223		setvar(name, val, flags);
224	}
225	handler = savehandler;
226	SETINTON(inton);
227	return err;
228}
229
230/*
231 * Set the value of a variable.  The flags argument is stored with the
232 * flags of the variable.  If val is NULL, the variable is unset.
233 */
234
235void
236setvar(const char *name, const char *val, int flags)
237{
238	const char *p;
239	int len;
240	int namelen;
241	char *nameeq;
242	int isbad;
243
244	isbad = 0;
245	p = name;
246	if (! is_name(*p))
247		isbad = 1;
248	p++;
249	for (;;) {
250		if (! is_in_name(*p)) {
251			if (*p == '\0' || *p == '=')
252				break;
253			isbad = 1;
254		}
255		p++;
256	}
257	namelen = p - name;
258	if (isbad)
259		error("%.*s: bad variable name", namelen, name);
260	len = namelen + 2;		/* 2 is space for '=' and '\0' */
261	if (val == NULL) {
262		flags |= VUNSET;
263	} else {
264		len += strlen(val);
265	}
266	nameeq = ckmalloc(len);
267	memcpy(nameeq, name, namelen);
268	nameeq[namelen] = '=';
269	if (val)
270		scopy(val, nameeq + namelen + 1);
271	else
272		nameeq[namelen + 1] = '\0';
273	setvareq(nameeq, flags);
274}
275
276static int
277localevar(const char *s)
278{
279	const char *const *ss;
280
281	if (*s != 'L')
282		return 0;
283	if (varequal(s + 1, "ANG"))
284		return 1;
285	if (strncmp(s + 1, "C_", 2) != 0)
286		return 0;
287	if (varequal(s + 3, "ALL"))
288		return 1;
289	for (ss = locale_names; *ss ; ss++)
290		if (varequal(s + 3, *ss + 3))
291			return 1;
292	return 0;
293}
294
295
296/*
297 * Sets/unsets an environment variable from a pointer that may actually be a
298 * pointer into environ where the string should not be manipulated.
299 */
300static void
301change_env(const char *s, int set)
302{
303	char *eqp;
304	char *ss;
305
306	ss = savestr(s);
307	if ((eqp = strchr(ss, '=')) != NULL)
308		*eqp = '\0';
309	if (set && eqp != NULL)
310		(void) setenv(ss, eqp + 1, 1);
311	else
312		(void) unsetenv(ss);
313	ckfree(ss);
314
315	return;
316}
317
318
319/*
320 * Same as setvar except that the variable and value are passed in
321 * the first argument as name=value.  Since the first argument will
322 * be actually stored in the table, it should not be a string that
323 * will go away.
324 */
325
326void
327setvareq(char *s, int flags)
328{
329	struct var *vp, **vpp;
330	int nlen;
331
332	if (aflag)
333		flags |= VEXPORT;
334	if (forcelocal && !(flags & (VNOSET | VNOLOCAL)))
335		mklocal(s);
336	vp = find_var(s, &vpp, &nlen);
337	if (vp != NULL) {
338		if (vp->flags & VREADONLY)
339			error("%.*s: is read only", vp->name_len, s);
340		if (flags & VNOSET)
341			return;
342		INTOFF;
343
344		if (vp->func && (flags & VNOFUNC) == 0)
345			(*vp->func)(s + vp->name_len + 1);
346
347		if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
348			ckfree(vp->text);
349
350		vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
351		vp->flags |= flags;
352		vp->text = s;
353
354		/*
355		 * We could roll this to a function, to handle it as
356		 * a regular variable function callback, but why bother?
357		 *
358		 * Note: this assumes iflag is not set to 1 initially.
359		 * As part of init(), this is called before arguments
360		 * are looked at.
361		 */
362		if ((vp == &vmpath || (vp == &vmail && ! mpathset())) &&
363		    iflag == 1)
364			chkmail(1);
365		if ((vp->flags & VEXPORT) && localevar(s)) {
366			change_env(s, 1);
367			(void) setlocale(LC_ALL, "");
368			updatecharset();
369		}
370		INTON;
371		return;
372	}
373	/* not found */
374	if (flags & VNOSET)
375		return;
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	INTOFF;
383	*vpp = vp;
384	if ((vp->flags & VEXPORT) && localevar(s)) {
385		change_env(s, 1);
386		(void) setlocale(LC_ALL, "");
387		updatecharset();
388	}
389	INTON;
390}
391
392
393
394/*
395 * Process a linked list of variable assignments.
396 */
397
398void
399listsetvar(struct strlist *list, int flags)
400{
401	struct strlist *lp;
402
403	INTOFF;
404	for (lp = list ; lp ; lp = lp->next) {
405		setvareq(savestr(lp->text), flags);
406	}
407	INTON;
408}
409
410
411
412/*
413 * Find the value of a variable.  Returns NULL if not set.
414 */
415
416char *
417lookupvar(const char *name)
418{
419	struct var *v;
420
421	v = find_var(name, NULL, NULL);
422	if (v == NULL || v->flags & VUNSET)
423		return NULL;
424	return v->text + v->name_len + 1;
425}
426
427
428
429/*
430 * Search the environment of a builtin command.  If the second argument
431 * is nonzero, return the value of a variable even if it hasn't been
432 * exported.
433 */
434
435char *
436bltinlookup(const char *name, int doall)
437{
438	struct strlist *sp;
439	struct var *v;
440	char *result;
441
442	result = NULL;
443	for (sp = cmdenviron ; sp ; sp = sp->next) {
444		if (varequal(sp->text, name))
445			result = strchr(sp->text, '=') + 1;
446	}
447	if (result != NULL)
448		return result;
449
450	v = find_var(name, NULL, NULL);
451	if (v == NULL || v->flags & VUNSET ||
452	    (!doall && (v->flags & VEXPORT) == 0))
453		return NULL;
454	return v->text + v->name_len + 1;
455}
456
457
458/*
459 * Set up locale for a builtin (LANG/LC_* assignments).
460 */
461void
462bltinsetlocale(void)
463{
464	struct strlist *lp;
465	int act = 0;
466	char *loc, *locdef;
467	int i;
468
469	for (lp = cmdenviron ; lp ; lp = lp->next) {
470		if (localevar(lp->text)) {
471			act = 1;
472			break;
473		}
474	}
475	if (!act)
476		return;
477	loc = bltinlookup("LC_ALL", 0);
478	INTOFF;
479	if (loc != NULL) {
480		setlocale(LC_ALL, loc);
481		INTON;
482		updatecharset();
483		return;
484	}
485	locdef = bltinlookup("LANG", 0);
486	for (i = 0; locale_names[i] != NULL; i++) {
487		loc = bltinlookup(locale_names[i], 0);
488		if (loc == NULL)
489			loc = locdef;
490		if (loc != NULL)
491			setlocale(locale_categories[i], loc);
492	}
493	INTON;
494	updatecharset();
495}
496
497/*
498 * Undo the effect of bltinlocaleset().
499 */
500void
501bltinunsetlocale(void)
502{
503	struct strlist *lp;
504
505	INTOFF;
506	for (lp = cmdenviron ; lp ; lp = lp->next) {
507		if (localevar(lp->text)) {
508			setlocale(LC_ALL, "");
509			updatecharset();
510			return;
511		}
512	}
513	INTON;
514}
515
516/*
517 * Update the localeisutf8 flag.
518 */
519void
520updatecharset(void)
521{
522	char *charset;
523
524	charset = nl_langinfo(CODESET);
525	localeisutf8 = !strcmp(charset, "UTF-8");
526}
527
528void
529initcharset(void)
530{
531	updatecharset();
532	initial_localeisutf8 = localeisutf8;
533}
534
535/*
536 * Generate a list of exported variables.  This routine is used to construct
537 * the third argument to execve when executing a program.
538 */
539
540char **
541environment(void)
542{
543	int nenv;
544	struct var **vpp;
545	struct var *vp;
546	char **env, **ep;
547
548	nenv = 0;
549	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
550		for (vp = *vpp ; vp ; vp = vp->next)
551			if (vp->flags & VEXPORT)
552				nenv++;
553	}
554	ep = env = stalloc((nenv + 1) * sizeof *env);
555	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
556		for (vp = *vpp ; vp ; vp = vp->next)
557			if (vp->flags & VEXPORT)
558				*ep++ = vp->text;
559	}
560	*ep = NULL;
561	return env;
562}
563
564
565static int
566var_compare(const void *a, const void *b)
567{
568	const char *const *sa, *const *sb;
569
570	sa = a;
571	sb = b;
572	/*
573	 * This compares two var=value strings which creates a different
574	 * order from what you would probably expect.  POSIX is somewhat
575	 * ambiguous on what should be sorted exactly.
576	 */
577	return strcoll(*sa, *sb);
578}
579
580
581/*
582 * Command to list all variables which are set.  This is invoked from the
583 * set command when it is called without any options or operands.
584 */
585
586int
587showvarscmd(int argc __unused, char **argv __unused)
588{
589	struct var **vpp;
590	struct var *vp;
591	const char *s;
592	const char **vars;
593	int i, n;
594
595	/*
596	 * POSIX requires us to sort the variables.
597	 */
598	n = 0;
599	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
600		for (vp = *vpp; vp; vp = vp->next) {
601			if (!(vp->flags & VUNSET))
602				n++;
603		}
604	}
605
606	INTOFF;
607	vars = ckmalloc(n * sizeof(*vars));
608	i = 0;
609	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
610		for (vp = *vpp; vp; vp = vp->next) {
611			if (!(vp->flags & VUNSET))
612				vars[i++] = vp->text;
613		}
614	}
615
616	qsort(vars, n, sizeof(*vars), var_compare);
617	for (i = 0; i < n; i++) {
618		/*
619		 * Skip improper variable names so the output remains usable as
620		 * shell input.
621		 */
622		if (!isassignment(vars[i]))
623			continue;
624		s = strchr(vars[i], '=');
625		s++;
626		outbin(vars[i], s - vars[i], out1);
627		out1qstr(s);
628		out1c('\n');
629	}
630	ckfree(vars);
631	INTON;
632
633	return 0;
634}
635
636
637
638/*
639 * The export and readonly commands.
640 */
641
642int
643exportcmd(int argc, char **argv)
644{
645	struct var **vpp;
646	struct var *vp;
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	optreset = optind = 1;
655	opterr = 0;
656	values = 0;
657	while ((ch = getopt(argc, argv, "p")) != -1) {
658		switch (ch) {
659		case 'p':
660			values = 1;
661			break;
662		case '?':
663		default:
664			error("unknown option: -%c", optopt);
665		}
666	}
667	argc -= optind;
668	argv += optind;
669
670	if (values && argc != 0)
671		error("-p requires no arguments");
672	if (argc != 0) {
673		while ((name = *argv++) != NULL) {
674			if ((p = strchr(name, '=')) != NULL) {
675				p++;
676			} else {
677				vp = find_var(name, NULL, NULL);
678				if (vp != NULL) {
679					vp->flags |= flag;
680					if ((vp->flags & VEXPORT) && localevar(vp->text)) {
681						change_env(vp->text, 1);
682						(void) setlocale(LC_ALL, "");
683						updatecharset();
684					}
685					continue;
686				}
687			}
688			setvar(name, p, flag);
689		}
690	} else {
691		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
692			for (vp = *vpp ; vp ; vp = vp->next) {
693				if (vp->flags & flag) {
694					if (values) {
695						/*
696						 * Skip improper variable names
697						 * so the output remains usable
698						 * as shell input.
699						 */
700						if (!isassignment(vp->text))
701							continue;
702						out1str(cmdname);
703						out1c(' ');
704					}
705					if (values && !(vp->flags & VUNSET)) {
706						outbin(vp->text,
707						    vp->name_len + 1, out1);
708						out1qstr(vp->text +
709						    vp->name_len + 1);
710					} else
711						outbin(vp->text, vp->name_len,
712						    out1);
713					out1c('\n');
714				}
715			}
716		}
717	}
718	return 0;
719}
720
721
722/*
723 * The "local" command.
724 */
725
726int
727localcmd(int argc __unused, char **argv __unused)
728{
729	char *name;
730
731	if (! in_function())
732		error("Not in a function");
733	while ((name = *argptr++) != NULL) {
734		mklocal(name);
735	}
736	return 0;
737}
738
739
740/*
741 * Make a variable a local variable.  When a variable is made local, it's
742 * value and flags are saved in a localvar structure.  The saved values
743 * will be restored when the shell function returns.  We handle the name
744 * "-" as a special case.
745 */
746
747void
748mklocal(char *name)
749{
750	struct localvar *lvp;
751	struct var **vpp;
752	struct var *vp;
753
754	INTOFF;
755	lvp = ckmalloc(sizeof (struct localvar));
756	if (name[0] == '-' && name[1] == '\0') {
757		lvp->text = ckmalloc(sizeof optlist);
758		memcpy(lvp->text, optlist, sizeof optlist);
759		vp = NULL;
760	} else {
761		vp = find_var(name, &vpp, NULL);
762		if (vp == NULL) {
763			if (strchr(name, '='))
764				setvareq(savestr(name), VSTRFIXED | VNOLOCAL);
765			else
766				setvar(name, NULL, VSTRFIXED | VNOLOCAL);
767			vp = *vpp;	/* the new variable */
768			lvp->text = NULL;
769			lvp->flags = VUNSET;
770		} else {
771			lvp->text = vp->text;
772			lvp->flags = vp->flags;
773			vp->flags |= VSTRFIXED|VTEXTFIXED;
774			if (name[vp->name_len] == '=')
775				setvareq(savestr(name), VNOLOCAL);
776		}
777	}
778	lvp->vp = vp;
779	lvp->next = localvars;
780	localvars = lvp;
781	INTON;
782}
783
784
785/*
786 * Called after a function returns.
787 */
788
789void
790poplocalvars(void)
791{
792	struct localvar *lvp;
793	struct var *vp;
794
795	while ((lvp = localvars) != NULL) {
796		localvars = lvp->next;
797		vp = lvp->vp;
798		if (vp == NULL) {	/* $- saved */
799			memcpy(optlist, lvp->text, sizeof optlist);
800			ckfree(lvp->text);
801			optschanged();
802		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
803			(void)unsetvar(vp->text);
804		} else {
805			if ((vp->flags & VTEXTFIXED) == 0)
806				ckfree(vp->text);
807			vp->flags = lvp->flags;
808			vp->text = lvp->text;
809		}
810		ckfree(lvp);
811	}
812}
813
814
815int
816setvarcmd(int argc, char **argv)
817{
818	if (argc <= 2)
819		return unsetcmd(argc, argv);
820	else if (argc == 3)
821		setvar(argv[1], argv[2], 0);
822	else
823		error("too many arguments");
824	return 0;
825}
826
827
828/*
829 * The unset builtin command.
830 */
831
832int
833unsetcmd(int argc __unused, char **argv __unused)
834{
835	char **ap;
836	int i;
837	int flg_func = 0;
838	int flg_var = 0;
839	int ret = 0;
840
841	while ((i = nextopt("vf")) != '\0') {
842		if (i == 'f')
843			flg_func = 1;
844		else
845			flg_var = 1;
846	}
847	if (flg_func == 0 && flg_var == 0)
848		flg_var = 1;
849
850	for (ap = argptr; *ap ; ap++) {
851		if (flg_func)
852			ret |= unsetfunc(*ap);
853		if (flg_var)
854			ret |= unsetvar(*ap);
855	}
856	return ret;
857}
858
859
860/*
861 * Unset the specified variable.
862 */
863
864int
865unsetvar(const char *s)
866{
867	struct var **vpp;
868	struct var *vp;
869
870	vp = find_var(s, &vpp, NULL);
871	if (vp == NULL)
872		return (0);
873	if (vp->flags & VREADONLY)
874		return (1);
875	INTOFF;
876	if (vp->text[vp->name_len + 1] != '\0')
877		setvar(s, nullstr, 0);
878	if ((vp->flags & VEXPORT) && localevar(vp->text)) {
879		change_env(s, 0);
880		setlocale(LC_ALL, "");
881		updatecharset();
882	}
883	vp->flags &= ~VEXPORT;
884	vp->flags |= VUNSET;
885	if ((vp->flags & VSTRFIXED) == 0) {
886		if ((vp->flags & VTEXTFIXED) == 0)
887			ckfree(vp->text);
888		*vpp = vp->next;
889		ckfree(vp);
890	}
891	INTON;
892	return (0);
893}
894
895
896
897/*
898 * Returns true if the two strings specify the same varable.  The first
899 * variable name is terminated by '='; the second may be terminated by
900 * either '=' or '\0'.
901 */
902
903static int
904varequal(const char *p, const char *q)
905{
906	while (*p == *q++) {
907		if (*p++ == '=')
908			return 1;
909	}
910	if (*p == '=' && *(q - 1) == '\0')
911		return 1;
912	return 0;
913}
914
915/*
916 * Search for a variable.
917 * 'name' may be terminated by '=' or a NUL.
918 * vppp is set to the pointer to vp, or the list head if vp isn't found
919 * lenp is set to the number of charactets in 'name'
920 */
921
922static struct var *
923find_var(const char *name, struct var ***vppp, int *lenp)
924{
925	unsigned int hashval;
926	int len;
927	struct var *vp, **vpp;
928	const char *p = name;
929
930	hashval = 0;
931	while (*p && *p != '=')
932		hashval = 2 * hashval + (unsigned char)*p++;
933	len = p - name;
934
935	if (lenp)
936		*lenp = len;
937	vpp = &vartab[hashval % VTABSIZE];
938	if (vppp)
939		*vppp = vpp;
940
941	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
942		if (vp->name_len != len)
943			continue;
944		if (memcmp(vp->text, name, len) != 0)
945			continue;
946		if (vppp)
947			*vppp = vpp;
948		return vp;
949	}
950	return NULL;
951}
952