var.c revision 100663 
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
41#endif /* not lint */
42#include <sys/cdefs.h>
43__FBSDID("$FreeBSD: head/bin/sh/var.c 100663 2002-07-25 10:47:38Z tjr $");
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)(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 vppid;
95struct var vps1;
96struct var vps2;
97struct var vvers;
98#if ATTY
99struct var vterm;
100#endif
101struct var voptind;
102
103const struct varinit varinit[] = {
104#if ATTY
105	{ &vatty,	VSTRFIXED|VTEXTFIXED|VUNSET,	"ATTY=",
106	  NULL },
107#endif
108#ifndef NO_HISTORY
109	{ &vhistsize,	VSTRFIXED|VTEXTFIXED|VUNSET,	"HISTSIZE=",
110	  sethistsize },
111#endif
112	{ &vifs,	VSTRFIXED|VTEXTFIXED,		"IFS= \t\n",
113	  NULL },
114	{ &vmail,	VSTRFIXED|VTEXTFIXED|VUNSET,	"MAIL=",
115	  NULL },
116	{ &vmpath,	VSTRFIXED|VTEXTFIXED|VUNSET,	"MAILPATH=",
117	  NULL },
118	{ &vpath,	VSTRFIXED|VTEXTFIXED,		"PATH=/bin:/usr/bin",
119	  changepath },
120	{ &vppid,	VSTRFIXED|VTEXTFIXED|VUNSET,	"PPID=",
121	  NULL },
122	/*
123	 * vps1 depends on uid
124	 */
125	{ &vps2,	VSTRFIXED|VTEXTFIXED,		"PS2=> ",
126	  NULL },
127#if ATTY
128	{ &vterm,	VSTRFIXED|VTEXTFIXED|VUNSET,	"TERM=",
129	  NULL },
130#endif
131	{ &voptind,	VSTRFIXED|VTEXTFIXED,		"OPTIND=1",
132	  getoptsreset },
133	{ NULL,	0,				NULL,
134	  NULL }
135};
136
137struct var *vartab[VTABSIZE];
138
139STATIC struct var **hashvar(char *);
140STATIC int varequal(char *, char *);
141STATIC int localevar(char *);
142
143/*
144 * Initialize the varable symbol tables and import the environment
145 */
146
147#ifdef mkinit
148INCLUDE "var.h"
149INIT {
150	char **envp;
151	extern char **environ;
152
153	initvar();
154	for (envp = environ ; *envp ; envp++) {
155		if (strchr(*envp, '=')) {
156			setvareq(*envp, VEXPORT|VTEXTFIXED);
157		}
158	}
159}
160#endif
161
162
163/*
164 * This routine initializes the builtin variables.  It is called when the
165 * shell is initialized and again when a shell procedure is spawned.
166 */
167
168void
169initvar(void)
170{
171	char ppid[20];
172	const struct varinit *ip;
173	struct var *vp;
174	struct var **vpp;
175
176	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
177		if ((vp->flags & VEXPORT) == 0) {
178			vpp = hashvar(ip->text);
179			vp->next = *vpp;
180			*vpp = vp;
181			vp->text = ip->text;
182			vp->flags = ip->flags;
183			vp->func = ip->func;
184		}
185	}
186	/*
187	 * PS1 depends on uid
188	 */
189	if ((vps1.flags & VEXPORT) == 0) {
190		vpp = hashvar("PS1=");
191		vps1.next = *vpp;
192		*vpp = &vps1;
193		vps1.text = 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(char *name, char *val, int flags)
208{
209	struct jmploc jmploc;
210	struct jmploc *volatile savehandler = handler;
211	int err = 0;
212#if __GNUC__
213	/* Avoid longjmp clobbering */
214	(void) &err;
215#endif
216
217	if (setjmp(jmploc.loc))
218		err = 1;
219	else {
220		handler = &jmploc;
221		setvar(name, val, flags);
222	}
223	handler = savehandler;
224	return err;
225}
226
227/*
228 * Set the value of a variable.  The flags argument is tored with the
229 * flags of the variable.  If val is NULL, the variable is unset.
230 */
231
232void
233setvar(char *name, char *val, int flags)
234{
235	char *p, *q;
236	int len;
237	int namelen;
238	char *nameeq;
239	int isbad;
240
241	isbad = 0;
242	p = name;
243	if (! is_name(*p))
244		isbad = 1;
245	p++;
246	for (;;) {
247		if (! is_in_name(*p)) {
248			if (*p == '\0' || *p == '=')
249				break;
250			isbad = 1;
251		}
252		p++;
253	}
254	namelen = p - name;
255	if (isbad)
256		error("%.*s: bad variable name", namelen, name);
257	len = namelen + 2;		/* 2 is space for '=' and '\0' */
258	if (val == NULL) {
259		flags |= VUNSET;
260	} else {
261		len += strlen(val);
262	}
263	p = nameeq = ckmalloc(len);
264	q = name;
265	while (--namelen >= 0)
266		*p++ = *q++;
267	*p++ = '=';
268	*p = '\0';
269	if (val)
270		scopy(val, p);
271	setvareq(nameeq, flags);
272}
273
274STATIC int
275localevar(char *s)
276{
277	static char *lnames[7] = {
278		"ALL", "COLLATE", "CTYPE", "MONETARY",
279		"NUMERIC", "TIME", NULL
280	};
281	char **ss;
282
283	if (*s != 'L')
284		return 0;
285	if (varequal(s + 1, "ANG"))
286		return 1;
287	if (strncmp(s + 1, "C_", 2) != 0)
288		return 0;
289	for (ss = lnames; *ss ; ss++)
290		if (varequal(s + 3, *ss))
291			return 1;
292	return 0;
293}
294
295/*
296 * Same as setvar except that the variable and value are passed in
297 * the first argument as name=value.  Since the first argument will
298 * be actually stored in the table, it should not be a string that
299 * will go away.
300 */
301
302void
303setvareq(char *s, int flags)
304{
305	struct var *vp, **vpp;
306	int len;
307
308	if (aflag)
309		flags |= VEXPORT;
310	vpp = hashvar(s);
311	for (vp = *vpp ; vp ; vp = vp->next) {
312		if (varequal(s, vp->text)) {
313			if (vp->flags & VREADONLY) {
314				len = strchr(s, '=') - s;
315				error("%.*s: is read only", len, s);
316			}
317			INTOFF;
318
319			if (vp->func && (flags & VNOFUNC) == 0)
320				(*vp->func)(strchr(s, '=') + 1);
321
322			if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
323				ckfree(vp->text);
324
325			vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
326			vp->flags |= flags;
327			vp->text = s;
328
329			/*
330			 * We could roll this to a function, to handle it as
331			 * a regular variable function callback, but why bother?
332			 */
333			if (vp == &vmpath || (vp == &vmail && ! mpathset()))
334				chkmail(1);
335			if ((vp->flags & VEXPORT) && localevar(s)) {
336				putenv(s);
337				(void) setlocale(LC_ALL, "");
338			}
339			INTON;
340			return;
341		}
342	}
343	/* not found */
344	vp = ckmalloc(sizeof (*vp));
345	vp->flags = flags;
346	vp->text = s;
347	vp->next = *vpp;
348	vp->func = NULL;
349	INTOFF;
350	*vpp = vp;
351	if ((vp->flags & VEXPORT) && localevar(s)) {
352		putenv(s);
353		(void) setlocale(LC_ALL, "");
354	}
355	INTON;
356}
357
358
359
360/*
361 * Process a linked list of variable assignments.
362 */
363
364void
365listsetvar(struct strlist *list)
366{
367	struct strlist *lp;
368
369	INTOFF;
370	for (lp = list ; lp ; lp = lp->next) {
371		setvareq(savestr(lp->text), 0);
372	}
373	INTON;
374}
375
376
377
378/*
379 * Find the value of a variable.  Returns NULL if not set.
380 */
381
382char *
383lookupvar(char *name)
384{
385	struct var *v;
386
387	for (v = *hashvar(name) ; v ; v = v->next) {
388		if (varequal(v->text, name)) {
389			if (v->flags & VUNSET)
390				return NULL;
391			return strchr(v->text, '=') + 1;
392		}
393	}
394	return NULL;
395}
396
397
398
399/*
400 * Search the environment of a builtin command.  If the second argument
401 * is nonzero, return the value of a variable even if it hasn't been
402 * exported.
403 */
404
405char *
406bltinlookup(char *name, int doall)
407{
408	struct strlist *sp;
409	struct var *v;
410
411	for (sp = cmdenviron ; sp ; sp = sp->next) {
412		if (varequal(sp->text, name))
413			return strchr(sp->text, '=') + 1;
414	}
415	for (v = *hashvar(name) ; v ; v = v->next) {
416		if (varequal(v->text, name)) {
417			if ((v->flags & VUNSET)
418			 || (!doall && (v->flags & VEXPORT) == 0))
419				return NULL;
420			return strchr(v->text, '=') + 1;
421		}
422	}
423	return NULL;
424}
425
426
427
428/*
429 * Generate a list of exported variables.  This routine is used to construct
430 * the third argument to execve when executing a program.
431 */
432
433char **
434environment(void)
435{
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(void)
474{
475	struct var **vpp;
476	struct var *vp, **prev;
477
478	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
479		for (prev = vpp ; (vp = *prev) != NULL ; ) {
480			if ((vp->flags & VEXPORT) == 0) {
481				*prev = vp->next;
482				if ((vp->flags & VTEXTFIXED) == 0)
483					ckfree(vp->text);
484				if ((vp->flags & VSTRFIXED) == 0)
485					ckfree(vp);
486			} else {
487				if (vp->flags & VSTACK) {
488					vp->text = savestr(vp->text);
489					vp->flags &=~ VSTACK;
490				}
491				prev = &vp->next;
492			}
493		}
494	}
495	initvar();
496}
497
498
499
500/*
501 * Command to list all variables which are set.  Currently this command
502 * is invoked from the set command when the set command is called without
503 * any variables.
504 */
505
506int
507showvarscmd(int argc __unused, char **argv __unused)
508{
509	struct var **vpp;
510	struct var *vp;
511	const char *s;
512
513	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
514		for (vp = *vpp ; vp ; vp = vp->next) {
515			if (vp->flags & VUNSET)
516				continue;
517			for (s = vp->text; *s != '='; s++)
518				out1c(*s);
519			out1c('=');
520			out1qstr(s + 1);
521			out1c('\n');
522		}
523	}
524	return 0;
525}
526
527
528
529/*
530 * The export and readonly commands.
531 */
532
533int
534exportcmd(int argc, char **argv)
535{
536	struct var **vpp;
537	struct var *vp;
538	char *name;
539	char *p;
540	char *cmdname;
541	int ch, values;
542	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
543
544	cmdname = argv[0];
545	optreset = optind = 1;
546	opterr = 0;
547	values = 0;
548	while ((ch = getopt(argc, argv, "p")) != -1) {
549		switch (ch) {
550		case 'p':
551			values = 1;
552			break;
553		case '?':
554		default:
555			error("unknown option: -%c", optopt);
556		}
557	}
558	argc -= optind;
559	argv += optind;
560
561	listsetvar(cmdenviron);
562	if (argc != 0) {
563		while ((name = *argptr++) != NULL) {
564			if ((p = strchr(name, '=')) != NULL) {
565				p++;
566			} else {
567				vpp = hashvar(name);
568				for (vp = *vpp ; vp ; vp = vp->next) {
569					if (varequal(vp->text, name)) {
570
571						vp->flags |= flag;
572						if ((vp->flags & VEXPORT) && localevar(vp->text)) {
573							putenv(vp->text);
574							(void) setlocale(LC_ALL, "");
575						}
576						goto found;
577					}
578				}
579			}
580			setvar(name, p, flag);
581found:;
582		}
583	} else {
584		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
585			for (vp = *vpp ; vp ; vp = vp->next) {
586				if (vp->flags & flag) {
587					if (values) {
588						out1str(cmdname);
589						out1c(' ');
590					}
591					for (p = vp->text ; *p != '=' ; p++)
592						out1c(*p);
593					if (values && !(vp->flags & VUNSET)) {
594						out1c('=');
595						out1qstr(p + 1);
596					}
597					out1c('\n');
598				}
599			}
600		}
601	}
602	return 0;
603}
604
605
606/*
607 * The "local" command.
608 */
609
610int
611localcmd(int argc __unused, char **argv __unused)
612{
613	char *name;
614
615	if (! in_function())
616		error("Not in a function");
617	while ((name = *argptr++) != NULL) {
618		mklocal(name);
619	}
620	return 0;
621}
622
623
624/*
625 * Make a variable a local variable.  When a variable is made local, it's
626 * value and flags are saved in a localvar structure.  The saved values
627 * will be restored when the shell function returns.  We handle the name
628 * "-" as a special case.
629 */
630
631void
632mklocal(char *name)
633{
634	struct localvar *lvp;
635	struct var **vpp;
636	struct var *vp;
637
638	INTOFF;
639	lvp = ckmalloc(sizeof (struct localvar));
640	if (name[0] == '-' && name[1] == '\0') {
641		lvp->text = ckmalloc(sizeof optlist);
642		memcpy(lvp->text, optlist, sizeof optlist);
643		vp = NULL;
644	} else {
645		vpp = hashvar(name);
646		for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next);
647		if (vp == NULL) {
648			if (strchr(name, '='))
649				setvareq(savestr(name), VSTRFIXED);
650			else
651				setvar(name, NULL, VSTRFIXED);
652			vp = *vpp;	/* the new variable */
653			lvp->text = NULL;
654			lvp->flags = VUNSET;
655		} else {
656			lvp->text = vp->text;
657			lvp->flags = vp->flags;
658			vp->flags |= VSTRFIXED|VTEXTFIXED;
659			if (strchr(name, '='))
660				setvareq(savestr(name), 0);
661		}
662	}
663	lvp->vp = vp;
664	lvp->next = localvars;
665	localvars = lvp;
666	INTON;
667}
668
669
670/*
671 * Called after a function returns.
672 */
673
674void
675poplocalvars(void)
676{
677	struct localvar *lvp;
678	struct var *vp;
679
680	while ((lvp = localvars) != NULL) {
681		localvars = lvp->next;
682		vp = lvp->vp;
683		if (vp == NULL) {	/* $- saved */
684			memcpy(optlist, lvp->text, sizeof optlist);
685			ckfree(lvp->text);
686		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
687			(void)unsetvar(vp->text);
688		} else {
689			if ((vp->flags & VTEXTFIXED) == 0)
690				ckfree(vp->text);
691			vp->flags = lvp->flags;
692			vp->text = lvp->text;
693		}
694		ckfree(lvp);
695	}
696}
697
698
699int
700setvarcmd(int argc, char **argv)
701{
702	if (argc <= 2)
703		return unsetcmd(argc, argv);
704	else if (argc == 3)
705		setvar(argv[1], argv[2], 0);
706	else
707		error("List assignment not implemented");
708	return 0;
709}
710
711
712/*
713 * The unset builtin command.  We unset the function before we unset the
714 * variable to allow a function to be unset when there is a readonly variable
715 * with the same name.
716 */
717
718int
719unsetcmd(int argc __unused, char **argv __unused)
720{
721	char **ap;
722	int i;
723	int flg_func = 0;
724	int flg_var = 0;
725	int ret = 0;
726
727	while ((i = nextopt("vf")) != '\0') {
728		if (i == 'f')
729			flg_func = 1;
730		else
731			flg_var = 1;
732	}
733	if (flg_func == 0 && flg_var == 0)
734		flg_var = 1;
735
736	for (ap = argptr; *ap ; ap++) {
737		if (flg_func)
738			ret |= unsetfunc(*ap);
739		if (flg_var)
740			ret |= unsetvar(*ap);
741	}
742	return ret;
743}
744
745
746/*
747 * Unset the specified variable.
748 */
749
750int
751unsetvar(char *s)
752{
753	struct var **vpp;
754	struct var *vp;
755
756	vpp = hashvar(s);
757	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
758		if (varequal(vp->text, s)) {
759			if (vp->flags & VREADONLY)
760				return (1);
761			INTOFF;
762			if (*(strchr(vp->text, '=') + 1) != '\0')
763				setvar(s, nullstr, 0);
764			if ((vp->flags & VEXPORT) && localevar(vp->text)) {
765				unsetenv(s);
766				setlocale(LC_ALL, "");
767			}
768			vp->flags &= ~VEXPORT;
769			vp->flags |= VUNSET;
770			if ((vp->flags & VSTRFIXED) == 0) {
771				if ((vp->flags & VTEXTFIXED) == 0)
772					ckfree(vp->text);
773				*vpp = vp->next;
774				ckfree(vp);
775			}
776			INTON;
777			return (0);
778		}
779	}
780
781	return (1);
782}
783
784
785
786/*
787 * Find the appropriate entry in the hash table from the name.
788 */
789
790STATIC struct var **
791hashvar(char *p)
792{
793	unsigned int hashval;
794
795	hashval = ((unsigned char) *p) << 4;
796	while (*p && *p != '=')
797		hashval += (unsigned char) *p++;
798	return &vartab[hashval % VTABSIZE];
799}
800
801
802
803/*
804 * Returns true if the two strings specify the same varable.  The first
805 * variable name is terminated by '='; the second may be terminated by
806 * either '=' or '\0'.
807 */
808
809STATIC int
810varequal(char *p, char *q)
811{
812	while (*p == *q++) {
813		if (*p++ == '=')
814			return 1;
815	}
816	if (*p == '=' && *(q - 1) == '\0')
817		return 1;
818	return 0;
819}
820