var.c revision 45621 
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: var.c,v 1.13 1999/04/03 11:41:46 cracauer Exp $";
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 tored 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	if (aflag)
306		flags |= VEXPORT;
307	vpp = hashvar(s);
308	for (vp = *vpp ; vp ; vp = vp->next) {
309		if (varequal(s, vp->text)) {
310			if (vp->flags & VREADONLY) {
311				size_t len = strchr(s, '=') - s;
312				error("%.*s: is read only", len, s);
313			}
314			INTOFF;
315
316			if (vp->func && (flags & VNOFUNC) == 0)
317				(*vp->func)(strchr(s, '=') + 1);
318
319			if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
320				ckfree(vp->text);
321
322			vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
323			vp->flags |= flags;
324			vp->text = s;
325
326			/*
327			 * We could roll this to a function, to handle it as
328			 * a regular variable function callback, but why bother?
329			 */
330			if (vp == &vmpath || (vp == &vmail && ! mpathset()))
331				chkmail(1);
332			if ((vp->flags & VEXPORT) && localevar(s)) {
333				putenv(s);
334				(void) setlocale(LC_ALL, "");
335			}
336			INTON;
337			return;
338		}
339	}
340	/* not found */
341	vp = ckmalloc(sizeof (*vp));
342	vp->flags = flags;
343	vp->text = s;
344	vp->next = *vpp;
345	vp->func = NULL;
346	INTOFF;
347	*vpp = vp;
348	if ((vp->flags & VEXPORT) && localevar(s)) {
349		putenv(s);
350		(void) setlocale(LC_ALL, "");
351	}
352	INTON;
353}
354
355
356
357/*
358 * Process a linked list of variable assignments.
359 */
360
361void
362listsetvar(list)
363	struct strlist *list;
364	{
365	struct strlist *lp;
366
367	INTOFF;
368	for (lp = list ; lp ; lp = lp->next) {
369		setvareq(savestr(lp->text), 0);
370	}
371	INTON;
372}
373
374
375
376/*
377 * Find the value of a variable.  Returns NULL if not set.
378 */
379
380char *
381lookupvar(name)
382	char *name;
383	{
384	struct var *v;
385
386	for (v = *hashvar(name) ; v ; v = v->next) {
387		if (varequal(v->text, name)) {
388			if (v->flags & VUNSET)
389				return NULL;
390			return strchr(v->text, '=') + 1;
391		}
392	}
393	return NULL;
394}
395
396
397
398/*
399 * Search the environment of a builtin command.  If the second argument
400 * is nonzero, return the value of a variable even if it hasn't been
401 * exported.
402 */
403
404char *
405bltinlookup(name, doall)
406	char *name;
407	int doall;
408{
409	struct strlist *sp;
410	struct var *v;
411
412	for (sp = cmdenviron ; sp ; sp = sp->next) {
413		if (varequal(sp->text, name))
414			return strchr(sp->text, '=') + 1;
415	}
416	for (v = *hashvar(name) ; v ; v = v->next) {
417		if (varequal(v->text, name)) {
418			if ((v->flags & VUNSET)
419			 || (!doall && (v->flags & VEXPORT) == 0))
420				return NULL;
421			return strchr(v->text, '=') + 1;
422		}
423	}
424	return NULL;
425}
426
427
428
429/*
430 * Generate a list of exported variables.  This routine is used to construct
431 * the third argument to execve when executing a program.
432 */
433
434char **
435environment() {
436	int nenv;
437	struct var **vpp;
438	struct var *vp;
439	char **env, **ep;
440
441	nenv = 0;
442	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
443		for (vp = *vpp ; vp ; vp = vp->next)
444			if (vp->flags & VEXPORT)
445				nenv++;
446	}
447	ep = env = stalloc((nenv + 1) * sizeof *env);
448	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
449		for (vp = *vpp ; vp ; vp = vp->next)
450			if (vp->flags & VEXPORT)
451				*ep++ = vp->text;
452	}
453	*ep = NULL;
454	return env;
455}
456
457
458/*
459 * Called when a shell procedure is invoked to clear out nonexported
460 * variables.  It is also necessary to reallocate variables of with
461 * VSTACK set since these are currently allocated on the stack.
462 */
463
464#ifdef mkinit
465MKINIT void shprocvar();
466
467SHELLPROC {
468	shprocvar();
469}
470#endif
471
472void
473shprocvar() {
474	struct var **vpp;
475	struct var *vp, **prev;
476
477	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
478		for (prev = vpp ; (vp = *prev) != NULL ; ) {
479			if ((vp->flags & VEXPORT) == 0) {
480				*prev = vp->next;
481				if ((vp->flags & VTEXTFIXED) == 0)
482					ckfree(vp->text);
483				if ((vp->flags & VSTRFIXED) == 0)
484					ckfree(vp);
485			} else {
486				if (vp->flags & VSTACK) {
487					vp->text = savestr(vp->text);
488					vp->flags &=~ VSTACK;
489				}
490				prev = &vp->next;
491			}
492		}
493	}
494	initvar();
495}
496
497
498
499/*
500 * Command to list all variables which are set.  Currently this command
501 * is invoked from the set command when the set command is called without
502 * any variables.
503 */
504
505int
506showvarscmd(argc, argv)
507	int argc __unused;
508	char **argv __unused;
509{
510	struct var **vpp;
511	struct var *vp;
512
513	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
514		for (vp = *vpp ; vp ; vp = vp->next) {
515			if ((vp->flags & VUNSET) == 0)
516				out1fmt("%s\n", vp->text);
517		}
518	}
519	return 0;
520}
521
522
523
524/*
525 * The export and readonly commands.
526 */
527
528int
529exportcmd(argc, argv)
530	int argc;
531	char **argv;
532{
533	struct var **vpp;
534	struct var *vp;
535	char *name;
536	char *p;
537	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
538
539	listsetvar(cmdenviron);
540	if (argc > 1) {
541		while ((name = *argptr++) != NULL) {
542			if ((p = strchr(name, '=')) != NULL) {
543				p++;
544			} else {
545				vpp = hashvar(name);
546				for (vp = *vpp ; vp ; vp = vp->next) {
547					if (varequal(vp->text, name)) {
548						vp->flags |= flag;
549						if ((vp->flags & VEXPORT) && localevar(vp->text)) {
550							putenv(vp->text);
551							(void) setlocale(LC_ALL, "");
552						}
553						goto found;
554					}
555				}
556			}
557			setvar(name, p, flag);
558found:;
559		}
560	} else {
561		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
562			for (vp = *vpp ; vp ; vp = vp->next) {
563				if (vp->flags & flag) {
564					for (p = vp->text ; *p != '=' ; p++)
565						out1c(*p);
566					out1c('\n');
567				}
568			}
569		}
570	}
571	return 0;
572}
573
574
575/*
576 * The "local" command.
577 */
578
579int
580localcmd(argc, argv)
581	int argc __unused;
582	char **argv __unused;
583{
584	char *name;
585
586	if (! in_function())
587		error("Not in a function");
588	while ((name = *argptr++) != NULL) {
589		mklocal(name);
590	}
591	return 0;
592}
593
594
595/*
596 * Make a variable a local variable.  When a variable is made local, it's
597 * value and flags are saved in a localvar structure.  The saved values
598 * will be restored when the shell function returns.  We handle the name
599 * "-" as a special case.
600 */
601
602void
603mklocal(name)
604	char *name;
605	{
606	struct localvar *lvp;
607	struct var **vpp;
608	struct var *vp;
609
610	INTOFF;
611	lvp = ckmalloc(sizeof (struct localvar));
612	if (name[0] == '-' && name[1] == '\0') {
613		lvp->text = ckmalloc(sizeof optlist);
614		memcpy(lvp->text, optlist, sizeof optlist);
615		vp = NULL;
616	} else {
617		vpp = hashvar(name);
618		for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next);
619		if (vp == NULL) {
620			if (strchr(name, '='))
621				setvareq(savestr(name), VSTRFIXED);
622			else
623				setvar(name, NULL, VSTRFIXED);
624			vp = *vpp;	/* the new variable */
625			lvp->text = NULL;
626			lvp->flags = VUNSET;
627		} else {
628			lvp->text = vp->text;
629			lvp->flags = vp->flags;
630			vp->flags |= VSTRFIXED|VTEXTFIXED;
631			if (strchr(name, '='))
632				setvareq(savestr(name), 0);
633		}
634	}
635	lvp->vp = vp;
636	lvp->next = localvars;
637	localvars = lvp;
638	INTON;
639}
640
641
642/*
643 * Called after a function returns.
644 */
645
646void
647poplocalvars() {
648	struct localvar *lvp;
649	struct var *vp;
650
651	while ((lvp = localvars) != NULL) {
652		localvars = lvp->next;
653		vp = lvp->vp;
654		if (vp == NULL) {	/* $- saved */
655			memcpy(optlist, lvp->text, sizeof optlist);
656			ckfree(lvp->text);
657		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
658			(void)unsetvar(vp->text);
659		} else {
660			if ((vp->flags & VTEXTFIXED) == 0)
661				ckfree(vp->text);
662			vp->flags = lvp->flags;
663			vp->text = lvp->text;
664		}
665		ckfree(lvp);
666	}
667}
668
669
670int
671setvarcmd(argc, argv)
672	int argc;
673	char **argv;
674{
675	if (argc <= 2)
676		return unsetcmd(argc, argv);
677	else if (argc == 3)
678		setvar(argv[1], argv[2], 0);
679	else
680		error("List assignment not implemented");
681	return 0;
682}
683
684
685/*
686 * The unset builtin command.  We unset the function before we unset the
687 * variable to allow a function to be unset when there is a readonly variable
688 * with the same name.
689 */
690
691int
692unsetcmd(argc, argv)
693	int argc __unused;
694	char **argv __unused;
695{
696	char **ap;
697	int i;
698	int flg_func = 0;
699	int flg_var = 0;
700	int ret = 0;
701
702	while ((i = nextopt("vf")) != '\0') {
703		if (i == 'f')
704			flg_func = 1;
705		else
706			flg_var = 1;
707	}
708	if (flg_func == 0 && flg_var == 0)
709		flg_var = 1;
710
711	for (ap = argptr; *ap ; ap++) {
712		if (flg_func)
713			ret |= unsetfunc(*ap);
714		if (flg_var)
715			ret |= unsetvar(*ap);
716	}
717	return ret;
718}
719
720
721/*
722 * Unset the specified variable.
723 */
724
725int
726unsetvar(s)
727	char *s;
728	{
729	struct var **vpp;
730	struct var *vp;
731
732	vpp = hashvar(s);
733	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
734		if (varequal(vp->text, s)) {
735			if (vp->flags & VREADONLY)
736				return (1);
737			INTOFF;
738			if (*(strchr(vp->text, '=') + 1) != '\0')
739				setvar(s, nullstr, 0);
740			if ((vp->flags & VEXPORT) && localevar(vp->text)) {
741				unsetenv(s);
742				setlocale(LC_ALL, "");
743			}
744			vp->flags &= ~VEXPORT;
745			vp->flags |= VUNSET;
746			if ((vp->flags & VSTRFIXED) == 0) {
747				if ((vp->flags & VTEXTFIXED) == 0)
748					ckfree(vp->text);
749				*vpp = vp->next;
750				ckfree(vp);
751			}
752			INTON;
753			return (0);
754		}
755	}
756
757	return (1);
758}
759
760
761
762/*
763 * Find the appropriate entry in the hash table from the name.
764 */
765
766STATIC struct var **
767hashvar(p)
768	char *p;
769	{
770	unsigned int hashval;
771
772	hashval = ((unsigned char) *p) << 4;
773	while (*p && *p != '=')
774		hashval += (unsigned char) *p++;
775	return &vartab[hashval % VTABSIZE];
776}
777
778
779
780/*
781 * Returns true if the two strings specify the same varable.  The first
782 * variable name is terminated by '='; the second may be terminated by
783 * either '=' or '\0'.
784 */
785
786STATIC int
787varequal(p, q)
788	char *p, *q;
789	{
790	while (*p == *q++) {
791		if (*p++ == '=')
792			return 1;
793	}
794	if (*p == '=' && *(q - 1) == '\0')
795		return 1;
796	return 0;
797}
798