var.c revision 223024 
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 223024 2011-06-12 23:06:04Z 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#ifndef NO_HISTORY
67#include "myhistedit.h"
68#endif
69
70
71#define VTABSIZE 39
72
73
74struct varinit {
75	struct var *var;
76	int flags;
77	const char *text;
78	void (*func)(const char *);
79};
80
81
82#ifndef NO_HISTORY
83struct var vhistsize;
84struct var vterm;
85#endif
86struct var vifs;
87struct var vmail;
88struct var vmpath;
89struct var vpath;
90struct var vppid;
91struct var vps1;
92struct var vps2;
93struct var vps4;
94struct var vvers;
95static struct var voptind;
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	{ &vppid,	VUNSET,				"PPID=",
113	  NULL },
114	/*
115	 * vps1 depends on uid
116	 */
117	{ &vps2,	0,				"PS2=> ",
118	  NULL },
119	{ &vps4,	0,				"PS4=+ ",
120	  NULL },
121#ifndef NO_HISTORY
122	{ &vterm,	VUNSET,				"TERM=",
123	  setterm },
124#endif
125	{ &voptind,	0,				"OPTIND=1",
126	  getoptsreset },
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
145/*
146 * Initialize the variable symbol tables and import the environment.
147 */
148
149#ifdef mkinit
150INCLUDE "var.h"
151MKINIT char **environ;
152INIT {
153	char **envp;
154
155	initvar();
156	for (envp = environ ; *envp ; envp++) {
157		if (strchr(*envp, '=')) {
158			setvareq(*envp, VEXPORT|VTEXTFIXED);
159		}
160	}
161}
162#endif
163
164
165/*
166 * This routine initializes the builtin variables.  It is called when the
167 * shell is initialized.
168 */
169
170void
171initvar(void)
172{
173	char ppid[20];
174	const struct varinit *ip;
175	struct var *vp;
176	struct var **vpp;
177
178	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
179		if (find_var(ip->text, &vpp, &vp->name_len) != NULL)
180			continue;
181		vp->next = *vpp;
182		*vpp = vp;
183		vp->text = __DECONST(char *, ip->text);
184		vp->flags = ip->flags | VSTRFIXED | VTEXTFIXED;
185		vp->func = ip->func;
186	}
187	/*
188	 * PS1 depends on uid
189	 */
190	if (find_var("PS1", &vpp, &vps1.name_len) == NULL) {
191		vps1.next = *vpp;
192		*vpp = &vps1;
193		vps1.text = __DECONST(char *, geteuid() ? "PS1=$ " : "PS1=# ");
194		vps1.flags = VSTRFIXED|VTEXTFIXED;
195	}
196	if ((vppid.flags & VEXPORT) == 0) {
197		fmtstr(ppid, sizeof(ppid), "%d", (int)getppid());
198		setvarsafe("PPID", ppid, 0);
199	}
200}
201
202/*
203 * Safe version of setvar, returns 1 on success 0 on failure.
204 */
205
206int
207setvarsafe(const char *name, const char *val, int flags)
208{
209	struct jmploc jmploc;
210	struct jmploc *const savehandler = handler;
211	int err = 0;
212	int inton;
213
214	inton = is_int_on();
215	if (setjmp(jmploc.loc))
216		err = 1;
217	else {
218		handler = &jmploc;
219		setvar(name, val, flags);
220	}
221	handler = savehandler;
222	SETINTON(inton);
223	return err;
224}
225
226/*
227 * Set the value of a variable.  The flags argument is stored with the
228 * flags of the variable.  If val is NULL, the variable is unset.
229 */
230
231void
232setvar(const char *name, const char *val, int flags)
233{
234	const char *p;
235	int len;
236	int namelen;
237	char *nameeq;
238	int isbad;
239
240	isbad = 0;
241	p = name;
242	if (! is_name(*p))
243		isbad = 1;
244	p++;
245	for (;;) {
246		if (! is_in_name(*p)) {
247			if (*p == '\0' || *p == '=')
248				break;
249			isbad = 1;
250		}
251		p++;
252	}
253	namelen = p - name;
254	if (isbad)
255		error("%.*s: bad variable name", namelen, name);
256	len = namelen + 2;		/* 2 is space for '=' and '\0' */
257	if (val == NULL) {
258		flags |= VUNSET;
259	} else {
260		len += strlen(val);
261	}
262	nameeq = ckmalloc(len);
263	memcpy(nameeq, name, namelen);
264	nameeq[namelen] = '=';
265	if (val)
266		scopy(val, nameeq + namelen + 1);
267	else
268		nameeq[namelen + 1] = '\0';
269	setvareq(nameeq, flags);
270}
271
272static int
273localevar(const char *s)
274{
275	const char *const *ss;
276
277	if (*s != 'L')
278		return 0;
279	if (varequal(s + 1, "ANG"))
280		return 1;
281	if (strncmp(s + 1, "C_", 2) != 0)
282		return 0;
283	if (varequal(s + 3, "ALL"))
284		return 1;
285	for (ss = locale_names; *ss ; ss++)
286		if (varequal(s + 3, *ss + 3))
287			return 1;
288	return 0;
289}
290
291
292/*
293 * Sets/unsets an environment variable from a pointer that may actually be a
294 * pointer into environ where the string should not be manipulated.
295 */
296static void
297change_env(const char *s, int set)
298{
299	char *eqp;
300	char *ss;
301
302	ss = savestr(s);
303	if ((eqp = strchr(ss, '=')) != NULL)
304		*eqp = '\0';
305	if (set && eqp != NULL)
306		(void) setenv(ss, eqp + 1, 1);
307	else
308		(void) unsetenv(ss);
309	ckfree(ss);
310
311	return;
312}
313
314
315/*
316 * Same as setvar except that the variable and value are passed in
317 * the first argument as name=value.  Since the first argument will
318 * be actually stored in the table, it should not be a string that
319 * will go away.
320 */
321
322void
323setvareq(char *s, int flags)
324{
325	struct var *vp, **vpp;
326	int nlen;
327
328	if (aflag)
329		flags |= VEXPORT;
330	if (forcelocal && !(flags & (VNOSET | VNOLOCAL)))
331		mklocal(s);
332	vp = find_var(s, &vpp, &nlen);
333	if (vp != NULL) {
334		if (vp->flags & VREADONLY)
335			error("%.*s: is read only", vp->name_len, s);
336		if (flags & VNOSET)
337			return;
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 init(), 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		return;
372	vp = ckmalloc(sizeof (*vp));
373	vp->flags = flags;
374	vp->text = s;
375	vp->name_len = nlen;
376	vp->next = *vpp;
377	vp->func = NULL;
378	INTOFF;
379	*vpp = vp;
380	if ((vp->flags & VEXPORT) && localevar(s)) {
381		change_env(s, 1);
382		(void) setlocale(LC_ALL, "");
383		updatecharset();
384	}
385	INTON;
386}
387
388
389
390/*
391 * Process a linked list of variable assignments.
392 */
393
394void
395listsetvar(struct strlist *list, int flags)
396{
397	struct strlist *lp;
398
399	INTOFF;
400	for (lp = list ; lp ; lp = lp->next) {
401		setvareq(savestr(lp->text), flags);
402	}
403	INTON;
404}
405
406
407
408/*
409 * Find the value of a variable.  Returns NULL if not set.
410 */
411
412char *
413lookupvar(const char *name)
414{
415	struct var *v;
416
417	v = find_var(name, NULL, NULL);
418	if (v == NULL || v->flags & VUNSET)
419		return NULL;
420	return v->text + v->name_len + 1;
421}
422
423
424
425/*
426 * Search the environment of a builtin command.  If the second argument
427 * is nonzero, return the value of a variable even if it hasn't been
428 * exported.
429 */
430
431char *
432bltinlookup(const char *name, int doall)
433{
434	struct strlist *sp;
435	struct var *v;
436	char *result;
437
438	result = NULL;
439	for (sp = cmdenviron ; sp ; sp = sp->next) {
440		if (varequal(sp->text, name))
441			result = strchr(sp->text, '=') + 1;
442	}
443	if (result != NULL)
444		return result;
445
446	v = find_var(name, NULL, NULL);
447	if (v == NULL || v->flags & VUNSET ||
448	    (!doall && (v->flags & VEXPORT) == 0))
449		return NULL;
450	return v->text + v->name_len + 1;
451}
452
453
454/*
455 * Set up locale for a builtin (LANG/LC_* assignments).
456 */
457void
458bltinsetlocale(void)
459{
460	struct strlist *lp;
461	int act = 0;
462	char *loc, *locdef;
463	int i;
464
465	for (lp = cmdenviron ; lp ; lp = lp->next) {
466		if (localevar(lp->text)) {
467			act = 1;
468			break;
469		}
470	}
471	if (!act)
472		return;
473	loc = bltinlookup("LC_ALL", 0);
474	INTOFF;
475	if (loc != NULL) {
476		setlocale(LC_ALL, loc);
477		INTON;
478		updatecharset();
479		return;
480	}
481	locdef = bltinlookup("LANG", 0);
482	for (i = 0; locale_names[i] != NULL; i++) {
483		loc = bltinlookup(locale_names[i], 0);
484		if (loc == NULL)
485			loc = locdef;
486		if (loc != NULL)
487			setlocale(locale_categories[i], loc);
488	}
489	INTON;
490	updatecharset();
491}
492
493/*
494 * Undo the effect of bltinlocaleset().
495 */
496void
497bltinunsetlocale(void)
498{
499	struct strlist *lp;
500
501	INTOFF;
502	for (lp = cmdenviron ; lp ; lp = lp->next) {
503		if (localevar(lp->text)) {
504			setlocale(LC_ALL, "");
505			updatecharset();
506			return;
507		}
508	}
509	INTON;
510}
511
512/*
513 * Update the localeisutf8 flag.
514 */
515void
516updatecharset(void)
517{
518	char *charset;
519
520	charset = nl_langinfo(CODESET);
521	localeisutf8 = !strcmp(charset, "UTF-8");
522}
523
524void
525initcharset(void)
526{
527	updatecharset();
528	initial_localeisutf8 = localeisutf8;
529}
530
531/*
532 * Generate a list of exported variables.  This routine is used to construct
533 * the third argument to execve when executing a program.
534 */
535
536char **
537environment(void)
538{
539	int nenv;
540	struct var **vpp;
541	struct var *vp;
542	char **env, **ep;
543
544	nenv = 0;
545	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
546		for (vp = *vpp ; vp ; vp = vp->next)
547			if (vp->flags & VEXPORT)
548				nenv++;
549	}
550	ep = env = stalloc((nenv + 1) * sizeof *env);
551	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
552		for (vp = *vpp ; vp ; vp = vp->next)
553			if (vp->flags & VEXPORT)
554				*ep++ = vp->text;
555	}
556	*ep = NULL;
557	return env;
558}
559
560
561static int
562var_compare(const void *a, const void *b)
563{
564	const char *const *sa, *const *sb;
565
566	sa = a;
567	sb = b;
568	/*
569	 * This compares two var=value strings which creates a different
570	 * order from what you would probably expect.  POSIX is somewhat
571	 * ambiguous on what should be sorted exactly.
572	 */
573	return strcoll(*sa, *sb);
574}
575
576
577/*
578 * Command to list all variables which are set.  This is invoked from the
579 * set command when it is called without any options or operands.
580 */
581
582int
583showvarscmd(int argc __unused, char **argv __unused)
584{
585	struct var **vpp;
586	struct var *vp;
587	const char *s;
588	const char **vars;
589	int i, n;
590
591	/*
592	 * POSIX requires us to sort the variables.
593	 */
594	n = 0;
595	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
596		for (vp = *vpp; vp; vp = vp->next) {
597			if (!(vp->flags & VUNSET))
598				n++;
599		}
600	}
601
602	INTON;
603	vars = ckmalloc(n * sizeof(*vars));
604	i = 0;
605	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
606		for (vp = *vpp; vp; vp = vp->next) {
607			if (!(vp->flags & VUNSET))
608				vars[i++] = vp->text;
609		}
610	}
611
612	qsort(vars, n, sizeof(*vars), var_compare);
613	for (i = 0; i < n; i++) {
614		s = strchr(vars[i], '=');
615		s++;
616		outbin(vars[i], s - vars[i], out1);
617		out1qstr(s);
618		out1c('\n');
619	}
620	ckfree(vars);
621	INTOFF;
622
623	return 0;
624}
625
626
627
628/*
629 * The export and readonly commands.
630 */
631
632int
633exportcmd(int argc, char **argv)
634{
635	struct var **vpp;
636	struct var *vp;
637	char *name;
638	char *p;
639	char *cmdname;
640	int ch, values;
641	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
642
643	cmdname = argv[0];
644	optreset = optind = 1;
645	opterr = 0;
646	values = 0;
647	while ((ch = getopt(argc, argv, "p")) != -1) {
648		switch (ch) {
649		case 'p':
650			values = 1;
651			break;
652		case '?':
653		default:
654			error("unknown option: -%c", optopt);
655		}
656	}
657	argc -= optind;
658	argv += optind;
659
660	if (values && argc != 0)
661		error("-p requires no arguments");
662	if (argc != 0) {
663		while ((name = *argv++) != NULL) {
664			if ((p = strchr(name, '=')) != NULL) {
665				p++;
666			} else {
667				vp = find_var(name, NULL, NULL);
668				if (vp != NULL) {
669					vp->flags |= flag;
670					if ((vp->flags & VEXPORT) && localevar(vp->text)) {
671						change_env(vp->text, 1);
672						(void) setlocale(LC_ALL, "");
673						updatecharset();
674					}
675					continue;
676				}
677			}
678			setvar(name, p, flag);
679		}
680	} else {
681		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
682			for (vp = *vpp ; vp ; vp = vp->next) {
683				if (vp->flags & flag) {
684					if (values) {
685						out1str(cmdname);
686						out1c(' ');
687					}
688					if (values && !(vp->flags & VUNSET)) {
689						outbin(vp->text,
690						    vp->name_len + 1, out1);
691						out1qstr(vp->text +
692						    vp->name_len + 1);
693					} else
694						outbin(vp->text, vp->name_len,
695						    out1);
696					out1c('\n');
697				}
698			}
699		}
700	}
701	return 0;
702}
703
704
705/*
706 * The "local" command.
707 */
708
709int
710localcmd(int argc __unused, char **argv __unused)
711{
712	char *name;
713
714	if (! in_function())
715		error("Not in a function");
716	while ((name = *argptr++) != NULL) {
717		mklocal(name);
718	}
719	return 0;
720}
721
722
723/*
724 * Make a variable a local variable.  When a variable is made local, it's
725 * value and flags are saved in a localvar structure.  The saved values
726 * will be restored when the shell function returns.  We handle the name
727 * "-" as a special case.
728 */
729
730void
731mklocal(char *name)
732{
733	struct localvar *lvp;
734	struct var **vpp;
735	struct var *vp;
736
737	INTOFF;
738	lvp = ckmalloc(sizeof (struct localvar));
739	if (name[0] == '-' && name[1] == '\0') {
740		lvp->text = ckmalloc(sizeof optlist);
741		memcpy(lvp->text, optlist, sizeof optlist);
742		vp = NULL;
743	} else {
744		vp = find_var(name, &vpp, NULL);
745		if (vp == NULL) {
746			if (strchr(name, '='))
747				setvareq(savestr(name), VSTRFIXED | VNOLOCAL);
748			else
749				setvar(name, NULL, VSTRFIXED | VNOLOCAL);
750			vp = *vpp;	/* the new variable */
751			lvp->text = NULL;
752			lvp->flags = VUNSET;
753		} else {
754			lvp->text = vp->text;
755			lvp->flags = vp->flags;
756			vp->flags |= VSTRFIXED|VTEXTFIXED;
757			if (name[vp->name_len] == '=')
758				setvareq(savestr(name), VNOLOCAL);
759		}
760	}
761	lvp->vp = vp;
762	lvp->next = localvars;
763	localvars = lvp;
764	INTON;
765}
766
767
768/*
769 * Called after a function returns.
770 */
771
772void
773poplocalvars(void)
774{
775	struct localvar *lvp;
776	struct var *vp;
777
778	while ((lvp = localvars) != NULL) {
779		localvars = lvp->next;
780		vp = lvp->vp;
781		if (vp == NULL) {	/* $- saved */
782			memcpy(optlist, lvp->text, sizeof optlist);
783			ckfree(lvp->text);
784			optschanged();
785		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
786			(void)unsetvar(vp->text);
787		} else {
788			if ((vp->flags & VTEXTFIXED) == 0)
789				ckfree(vp->text);
790			vp->flags = lvp->flags;
791			vp->text = lvp->text;
792		}
793		ckfree(lvp);
794	}
795}
796
797
798int
799setvarcmd(int argc, char **argv)
800{
801	if (argc <= 2)
802		return unsetcmd(argc, argv);
803	else if (argc == 3)
804		setvar(argv[1], argv[2], 0);
805	else
806		error("too many arguments");
807	return 0;
808}
809
810
811/*
812 * The unset builtin command.
813 */
814
815int
816unsetcmd(int argc __unused, char **argv __unused)
817{
818	char **ap;
819	int i;
820	int flg_func = 0;
821	int flg_var = 0;
822	int ret = 0;
823
824	while ((i = nextopt("vf")) != '\0') {
825		if (i == 'f')
826			flg_func = 1;
827		else
828			flg_var = 1;
829	}
830	if (flg_func == 0 && flg_var == 0)
831		flg_var = 1;
832
833	for (ap = argptr; *ap ; ap++) {
834		if (flg_func)
835			ret |= unsetfunc(*ap);
836		if (flg_var)
837			ret |= unsetvar(*ap);
838	}
839	return ret;
840}
841
842
843/*
844 * Unset the specified variable.
845 */
846
847int
848unsetvar(const char *s)
849{
850	struct var **vpp;
851	struct var *vp;
852
853	vp = find_var(s, &vpp, NULL);
854	if (vp == NULL)
855		return (0);
856	if (vp->flags & VREADONLY)
857		return (1);
858	INTOFF;
859	if (vp->text[vp->name_len + 1] != '\0')
860		setvar(s, nullstr, 0);
861	if ((vp->flags & VEXPORT) && localevar(vp->text)) {
862		change_env(s, 0);
863		setlocale(LC_ALL, "");
864		updatecharset();
865	}
866	vp->flags &= ~VEXPORT;
867	vp->flags |= VUNSET;
868	if ((vp->flags & VSTRFIXED) == 0) {
869		if ((vp->flags & VTEXTFIXED) == 0)
870			ckfree(vp->text);
871		*vpp = vp->next;
872		ckfree(vp);
873	}
874	INTON;
875	return (0);
876}
877
878
879
880/*
881 * Returns true if the two strings specify the same varable.  The first
882 * variable name is terminated by '='; the second may be terminated by
883 * either '=' or '\0'.
884 */
885
886static int
887varequal(const char *p, const char *q)
888{
889	while (*p == *q++) {
890		if (*p++ == '=')
891			return 1;
892	}
893	if (*p == '=' && *(q - 1) == '\0')
894		return 1;
895	return 0;
896}
897
898/*
899 * Search for a variable.
900 * 'name' may be terminated by '=' or a NUL.
901 * vppp is set to the pointer to vp, or the list head if vp isn't found
902 * lenp is set to the number of charactets in 'name'
903 */
904
905static struct var *
906find_var(const char *name, struct var ***vppp, int *lenp)
907{
908	unsigned int hashval;
909	int len;
910	struct var *vp, **vpp;
911	const char *p = name;
912
913	hashval = 0;
914	while (*p && *p != '=')
915		hashval = 2 * hashval + (unsigned char)*p++;
916	len = p - name;
917
918	if (lenp)
919		*lenp = len;
920	vpp = &vartab[hashval % VTABSIZE];
921	if (vppp)
922		*vppp = vpp;
923
924	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
925		if (vp->name_len != len)
926			continue;
927		if (memcmp(vp->text, name, len) != 0)
928			continue;
929		if (vppp)
930			*vppp = vpp;
931		return vp;
932	}
933	return NULL;
934}
935