var.c revision 36150 
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 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#ifndef lint
38#if 0
39static char sccsid[] = "@(#)var.c	8.3 (Berkeley) 5/4/95";
40#endif
41static const char rcsid[] =
42	"$Id$";
43#endif /* not lint */
44
45#include <unistd.h>
46#include <stdlib.h>
47
48/*
49 * Shell variables.
50 */
51
52#include <locale.h>
53
54#include "shell.h"
55#include "output.h"
56#include "expand.h"
57#include "nodes.h"	/* for other headers */
58#include "eval.h"	/* defines cmdenviron */
59#include "exec.h"
60#include "syntax.h"
61#include "options.h"
62#include "mail.h"
63#include "var.h"
64#include "memalloc.h"
65#include "error.h"
66#include "mystring.h"
67#include "parser.h"
68#ifndef NO_HISTORY
69#include "myhistedit.h"
70#endif
71
72
73#define VTABSIZE 39
74
75
76struct varinit {
77	struct var *var;
78	int flags;
79	char *text;
80	void (*func) __P((const char *));
81};
82
83
84#if ATTY
85struct var vatty;
86#endif
87#ifndef NO_HISTORY
88struct var vhistsize;
89#endif
90struct var vifs;
91struct var vmail;
92struct var vmpath;
93struct var vpath;
94struct var vps1;
95struct var vps2;
96struct var vvers;
97#if ATTY
98struct var vterm;
99#endif
100struct var voptind;
101
102const struct varinit varinit[] = {
103#if ATTY
104	{ &vatty,	VSTRFIXED|VTEXTFIXED|VUNSET,	"ATTY=",
105	  NULL },
106#endif
107#ifndef NO_HISTORY
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=/bin:/usr/bin",
118	  changepath },
119	/*
120	 * vps1 depends on uid
121	 */
122	{ &vps2,	VSTRFIXED|VTEXTFIXED,		"PS2=> ",
123	  NULL },
124#if ATTY
125	{ &vterm,	VSTRFIXED|VTEXTFIXED|VUNSET,	"TERM=",
126	  NULL },
127#endif
128	{ &voptind,	VSTRFIXED|VTEXTFIXED,		"OPTIND=1",
129	  getoptsreset },
130	{ NULL,	0,				NULL,
131	  NULL }
132};
133
134struct var *vartab[VTABSIZE];
135
136STATIC struct var **hashvar __P((char *));
137STATIC int varequal __P((char *, char *));
138STATIC int localevar __P((char *));
139
140/*
141 * Initialize the varable symbol tables and import the environment
142 */
143
144#ifdef mkinit
145INCLUDE "var.h"
146INIT {
147	char **envp;
148	extern char **environ;
149
150	initvar();
151	for (envp = environ ; *envp ; envp++) {
152		if (strchr(*envp, '=')) {
153			setvareq(*envp, VEXPORT|VTEXTFIXED);
154		}
155	}
156}
157#endif
158
159
160/*
161 * This routine initializes the builtin variables.  It is called when the
162 * shell is initialized and again when a shell procedure is spawned.
163 */
164
165void
166initvar() {
167	const struct varinit *ip;
168	struct var *vp;
169	struct var **vpp;
170
171	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
172		if ((vp->flags & VEXPORT) == 0) {
173			vpp = hashvar(ip->text);
174			vp->next = *vpp;
175			*vpp = vp;
176			vp->text = ip->text;
177			vp->flags = ip->flags;
178			vp->func = ip->func;
179		}
180	}
181	/*
182	 * PS1 depends on uid
183	 */
184	if ((vps1.flags & VEXPORT) == 0) {
185		vpp = hashvar("PS1=");
186		vps1.next = *vpp;
187		*vpp = &vps1;
188		vps1.text = geteuid() ? "PS1=$ " : "PS1=# ";
189		vps1.flags = VSTRFIXED|VTEXTFIXED;
190	}
191}
192
193/*
194 * Safe version of setvar, returns 1 on success 0 on failure.
195 */
196
197int
198setvarsafe(name, val, flags)
199	char *name, *val;
200	int flags;
201{
202	struct jmploc jmploc;
203	struct jmploc *volatile savehandler = handler;
204	int err = 0;
205#if __GNUC__
206	/* Avoid longjmp clobbering */
207	(void) &err;
208#endif
209
210	if (setjmp(jmploc.loc))
211		err = 1;
212	else {
213		handler = &jmploc;
214		setvar(name, val, flags);
215	}
216	handler = savehandler;
217	return err;
218}
219
220/*
221 * Set the value of a variable.  The flags argument is ored with the
222 * flags of the variable.  If val is NULL, the variable is unset.
223 */
224
225void
226setvar(name, val, flags)
227	char *name, *val;
228	int flags;
229{
230	char *p, *q;
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	p = nameeq = ckmalloc(len);
259	q = name;
260	while (--namelen >= 0)
261		*p++ = *q++;
262	*p++ = '=';
263	*p = '\0';
264	if (val)
265		scopy(val, p);
266	setvareq(nameeq, flags);
267}
268
269STATIC int
270localevar(s)
271	char *s;
272	{
273	static char *lnames[7] = {
274		"ALL", "COLLATE", "CTYPE", "MONETARY",
275		"NUMERIC", "TIME", NULL
276	};
277	char **ss;
278
279	if (*s != 'L')
280		return 0;
281	if (varequal(s + 1, "ANG"))
282		return 1;
283	if (strncmp(s + 1, "C_", 2) != 0)
284		return 0;
285	for (ss = lnames; *ss ; ss++)
286		if (varequal(s + 3, *ss))
287			return 1;
288	return 0;
289}
290
291/*
292 * Same as setvar except that the variable and value are passed in
293 * the first argument as name=value.  Since the first argument will
294 * be actually stored in the table, it should not be a string that
295 * will go away.
296 */
297
298void
299setvareq(s, flags)
300	char *s;
301	int flags;
302{
303	struct var *vp, **vpp;
304
305	vpp = hashvar(s);
306	for (vp = *vpp ; vp ; vp = vp->next) {
307		if (varequal(s, vp->text)) {
308			if (vp->flags & VREADONLY) {
309				size_t len = strchr(s, '=') - s;
310				error("%.*s: is read only", len, s);
311			}
312			INTOFF;
313
314			if (vp->func && (flags & VNOFUNC) == 0)
315				(*vp->func)(strchr(s, '=') + 1);
316
317			if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
318				ckfree(vp->text);
319
320			vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
321			vp->flags |= flags;
322			vp->text = s;
323
324			/*
325			 * We could roll this to a function, to handle it as
326			 * a regular variable function callback, but why bother?
327			 */
328			if (vp == &vmpath || (vp == &vmail && ! mpathset()))
329				chkmail(1);
330			if ((vp->flags & VEXPORT) && localevar(s)) {
331				putenv(s);
332				(void) setlocale(LC_ALL, "");
333			}
334			INTON;
335			return;
336		}
337	}
338	/* not found */
339	vp = ckmalloc(sizeof (*vp));
340	vp->flags = flags;
341	vp->text = s;
342	vp->next = *vpp;
343	vp->func = NULL;
344	INTOFF;
345	*vpp = vp;
346	if ((vp->flags & VEXPORT) && localevar(s)) {
347		putenv(s);
348		(void) setlocale(LC_ALL, "");
349	}
350	INTON;
351}
352
353
354
355/*
356 * Process a linked list of variable assignments.
357 */
358
359void
360listsetvar(list)
361	struct strlist *list;
362	{
363	struct strlist *lp;
364
365	INTOFF;
366	for (lp = list ; lp ; lp = lp->next) {
367		setvareq(savestr(lp->text), 0);
368	}
369	INTON;
370}
371
372
373
374/*
375 * Find the value of a variable.  Returns NULL if not set.
376 */
377
378char *
379lookupvar(name)
380	char *name;
381	{
382	struct var *v;
383
384	for (v = *hashvar(name) ; v ; v = v->next) {
385		if (varequal(v->text, name)) {
386			if (v->flags & VUNSET)
387				return NULL;
388			return strchr(v->text, '=') + 1;
389		}
390	}
391	return NULL;
392}
393
394
395
396/*
397 * Search the environment of a builtin command.  If the second argument
398 * is nonzero, return the value of a variable even if it hasn't been
399 * exported.
400 */
401
402char *
403bltinlookup(name, doall)
404	char *name;
405	int doall;
406{
407	struct strlist *sp;
408	struct var *v;
409
410	for (sp = cmdenviron ; sp ; sp = sp->next) {
411		if (varequal(sp->text, name))
412			return strchr(sp->text, '=') + 1;
413	}
414	for (v = *hashvar(name) ; v ; v = v->next) {
415		if (varequal(v->text, name)) {
416			if ((v->flags & VUNSET)
417			 || (!doall && (v->flags & VEXPORT) == 0))
418				return NULL;
419			return strchr(v->text, '=') + 1;
420		}
421	}
422	return NULL;
423}
424
425
426
427/*
428 * Generate a list of exported variables.  This routine is used to construct
429 * the third argument to execve when executing a program.
430 */
431
432char **
433environment() {
434	int nenv;
435	struct var **vpp;
436	struct var *vp;
437	char **env, **ep;
438
439	nenv = 0;
440	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
441		for (vp = *vpp ; vp ; vp = vp->next)
442			if (vp->flags & VEXPORT)
443				nenv++;
444	}
445	ep = env = stalloc((nenv + 1) * sizeof *env);
446	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
447		for (vp = *vpp ; vp ; vp = vp->next)
448			if (vp->flags & VEXPORT)
449				*ep++ = vp->text;
450	}
451	*ep = NULL;
452	return env;
453}
454
455
456/*
457 * Called when a shell procedure is invoked to clear out nonexported
458 * variables.  It is also necessary to reallocate variables of with
459 * VSTACK set since these are currently allocated on the stack.
460 */
461
462#ifdef mkinit
463MKINIT void shprocvar();
464
465SHELLPROC {
466	shprocvar();
467}
468#endif
469
470void
471shprocvar() {
472	struct var **vpp;
473	struct var *vp, **prev;
474
475	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
476		for (prev = vpp ; (vp = *prev) != NULL ; ) {
477			if ((vp->flags & VEXPORT) == 0) {
478				*prev = vp->next;
479				if ((vp->flags & VTEXTFIXED) == 0)
480					ckfree(vp->text);
481				if ((vp->flags & VSTRFIXED) == 0)
482					ckfree(vp);
483			} else {
484				if (vp->flags & VSTACK) {
485					vp->text = savestr(vp->text);
486					vp->flags &=~ VSTACK;
487				}
488				prev = &vp->next;
489			}
490		}
491	}
492	initvar();
493}
494
495
496
497/*
498 * Command to list all variables which are set.  Currently this command
499 * is invoked from the set command when the set command is called without
500 * any variables.
501 */
502
503int
504showvarscmd(argc, argv)
505	int argc __unused;
506	char **argv __unused;
507{
508	struct var **vpp;
509	struct var *vp;
510
511	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
512		for (vp = *vpp ; vp ; vp = vp->next) {
513			if ((vp->flags & VUNSET) == 0)
514				out1fmt("%s\n", vp->text);
515		}
516	}
517	return 0;
518}
519
520
521
522/*
523 * The export and readonly commands.
524 */
525
526int
527exportcmd(argc, argv)
528	int argc;
529	char **argv;
530{
531	struct var **vpp;
532	struct var *vp;
533	char *name;
534	char *p;
535	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
536
537	listsetvar(cmdenviron);
538	if (argc > 1) {
539		while ((name = *argptr++) != NULL) {
540			if ((p = strchr(name, '=')) != NULL) {
541				p++;
542			} else {
543				vpp = hashvar(name);
544				for (vp = *vpp ; vp ; vp = vp->next) {
545					if (varequal(vp->text, name)) {
546						vp->flags |= flag;
547						if ((vp->flags & VEXPORT) && localevar(vp->text)) {
548							putenv(vp->text);
549							(void) setlocale(LC_ALL, "");
550						}
551						goto found;
552					}
553				}
554			}
555			setvar(name, p, flag);
556found:;
557		}
558	} else {
559		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
560			for (vp = *vpp ; vp ; vp = vp->next) {
561				if (vp->flags & flag) {
562					for (p = vp->text ; *p != '=' ; p++)
563						out1c(*p);
564					out1c('\n');
565				}
566			}
567		}
568	}
569	return 0;
570}
571
572
573/*
574 * The "local" command.
575 */
576
577int
578localcmd(argc, argv)
579	int argc __unused;
580	char **argv __unused;
581{
582	char *name;
583
584	if (! in_function())
585		error("Not in a function");
586	while ((name = *argptr++) != NULL) {
587		mklocal(name);
588	}
589	return 0;
590}
591
592
593/*
594 * Make a variable a local variable.  When a variable is made local, it's
595 * value and flags are saved in a localvar structure.  The saved values
596 * will be restored when the shell function returns.  We handle the name
597 * "-" as a special case.
598 */
599
600void
601mklocal(name)
602	char *name;
603	{
604	struct localvar *lvp;
605	struct var **vpp;
606	struct var *vp;
607
608	INTOFF;
609	lvp = ckmalloc(sizeof (struct localvar));
610	if (name[0] == '-' && name[1] == '\0') {
611		lvp->text = ckmalloc(sizeof optlist);
612		memcpy(lvp->text, optlist, sizeof optlist);
613		vp = NULL;
614	} else {
615		vpp = hashvar(name);
616		for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next);
617		if (vp == NULL) {
618			if (strchr(name, '='))
619				setvareq(savestr(name), VSTRFIXED);
620			else
621				setvar(name, NULL, VSTRFIXED);
622			vp = *vpp;	/* the new variable */
623			lvp->text = NULL;
624			lvp->flags = VUNSET;
625		} else {
626			lvp->text = vp->text;
627			lvp->flags = vp->flags;
628			vp->flags |= VSTRFIXED|VTEXTFIXED;
629			if (strchr(name, '='))
630				setvareq(savestr(name), 0);
631		}
632	}
633	lvp->vp = vp;
634	lvp->next = localvars;
635	localvars = lvp;
636	INTON;
637}
638
639
640/*
641 * Called after a function returns.
642 */
643
644void
645poplocalvars() {
646	struct localvar *lvp;
647	struct var *vp;
648
649	while ((lvp = localvars) != NULL) {
650		localvars = lvp->next;
651		vp = lvp->vp;
652		if (vp == NULL) {	/* $- saved */
653			memcpy(optlist, lvp->text, sizeof optlist);
654			ckfree(lvp->text);
655		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
656			(void)unsetvar(vp->text);
657		} else {
658			if ((vp->flags & VTEXTFIXED) == 0)
659				ckfree(vp->text);
660			vp->flags = lvp->flags;
661			vp->text = lvp->text;
662		}
663		ckfree(lvp);
664	}
665}
666
667
668int
669setvarcmd(argc, argv)
670	int argc;
671	char **argv;
672{
673	if (argc <= 2)
674		return unsetcmd(argc, argv);
675	else if (argc == 3)
676		setvar(argv[1], argv[2], 0);
677	else
678		error("List assignment not implemented");
679	return 0;
680}
681
682
683/*
684 * The unset builtin command.  We unset the function before we unset the
685 * variable to allow a function to be unset when there is a readonly variable
686 * with the same name.
687 */
688
689int
690unsetcmd(argc, argv)
691	int argc __unused;
692	char **argv __unused;
693{
694	char **ap;
695	int i;
696	int flg_func = 0;
697	int flg_var = 0;
698	int ret = 0;
699
700	while ((i = nextopt("vf")) != '\0') {
701		if (i == 'f')
702			flg_func = 1;
703		else
704			flg_var = 1;
705	}
706	if (flg_func == 0 && flg_var == 0)
707		flg_var = 1;
708
709	for (ap = argptr; *ap ; ap++) {
710		if (flg_func)
711			ret |= unsetfunc(*ap);
712		if (flg_var)
713			ret |= unsetvar(*ap);
714	}
715	return ret;
716}
717
718
719/*
720 * Unset the specified variable.
721 */
722
723int
724unsetvar(s)
725	char *s;
726	{
727	struct var **vpp;
728	struct var *vp;
729
730	vpp = hashvar(s);
731	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
732		if (varequal(vp->text, s)) {
733			if (vp->flags & VREADONLY)
734				return (1);
735			INTOFF;
736			if (*(strchr(vp->text, '=') + 1) != '\0')
737				setvar(s, nullstr, 0);
738			if ((vp->flags & VEXPORT) && localevar(vp->text)) {
739				unsetenv(s);
740				setlocale(LC_ALL, "");
741			}
742			vp->flags &= ~VEXPORT;
743			vp->flags |= VUNSET;
744			if ((vp->flags & VSTRFIXED) == 0) {
745				if ((vp->flags & VTEXTFIXED) == 0)
746					ckfree(vp->text);
747				*vpp = vp->next;
748				ckfree(vp);
749			}
750			INTON;
751			return (0);
752		}
753	}
754
755	return (1);
756}
757
758
759
760/*
761 * Find the appropriate entry in the hash table from the name.
762 */
763
764STATIC struct var **
765hashvar(p)
766	char *p;
767	{
768	unsigned int hashval;
769
770	hashval = ((unsigned char) *p) << 4;
771	while (*p && *p != '=')
772		hashval += (unsigned char) *p++;
773	return &vartab[hashval % VTABSIZE];
774}
775
776
777
778/*
779 * Returns true if the two strings specify the same varable.  The first
780 * variable name is terminated by '='; the second may be terminated by
781 * either '=' or '\0'.
782 */
783
784STATIC int
785varequal(p, q)
786	char *p, *q;
787	{
788	while (*p == *q++) {
789		if (*p++ == '=')
790			return 1;
791	}
792	if (*p == '=' && *(q - 1) == '\0')
793		return 1;
794	return 0;
795}
796