var.c revision 104255 
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 104255 2002-10-01 00:54:14Z 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#ifndef NO_HISTORY
85struct var vhistsize;
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 vvers;
95struct var voptind;
96
97const struct varinit varinit[] = {
98#ifndef NO_HISTORY
99	{ &vhistsize,	VSTRFIXED|VTEXTFIXED|VUNSET,	"HISTSIZE=",
100	  sethistsize },
101#endif
102	{ &vifs,	VSTRFIXED|VTEXTFIXED,		"IFS= \t\n",
103	  NULL },
104	{ &vmail,	VSTRFIXED|VTEXTFIXED|VUNSET,	"MAIL=",
105	  NULL },
106	{ &vmpath,	VSTRFIXED|VTEXTFIXED|VUNSET,	"MAILPATH=",
107	  NULL },
108	{ &vpath,	VSTRFIXED|VTEXTFIXED,		"PATH=/bin:/usr/bin",
109	  changepath },
110	{ &vppid,	VSTRFIXED|VTEXTFIXED|VUNSET,	"PPID=",
111	  NULL },
112	/*
113	 * vps1 depends on uid
114	 */
115	{ &vps2,	VSTRFIXED|VTEXTFIXED,		"PS2=> ",
116	  NULL },
117	{ &voptind,	VSTRFIXED|VTEXTFIXED,		"OPTIND=1",
118	  getoptsreset },
119	{ NULL,	0,				NULL,
120	  NULL }
121};
122
123struct var *vartab[VTABSIZE];
124
125STATIC struct var **hashvar(char *);
126STATIC int varequal(char *, char *);
127STATIC int localevar(char *);
128
129/*
130 * Initialize the varable symbol tables and import the environment
131 */
132
133#ifdef mkinit
134INCLUDE "var.h"
135INIT {
136	char **envp;
137	extern char **environ;
138
139	initvar();
140	for (envp = environ ; *envp ; envp++) {
141		if (strchr(*envp, '=')) {
142			setvareq(*envp, VEXPORT|VTEXTFIXED);
143		}
144	}
145}
146#endif
147
148
149/*
150 * This routine initializes the builtin variables.  It is called when the
151 * shell is initialized and again when a shell procedure is spawned.
152 */
153
154void
155initvar(void)
156{
157	char ppid[20];
158	const struct varinit *ip;
159	struct var *vp;
160	struct var **vpp;
161
162	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
163		if ((vp->flags & VEXPORT) == 0) {
164			vpp = hashvar(ip->text);
165			vp->next = *vpp;
166			*vpp = vp;
167			vp->text = ip->text;
168			vp->flags = ip->flags;
169			vp->func = ip->func;
170		}
171	}
172	/*
173	 * PS1 depends on uid
174	 */
175	if ((vps1.flags & VEXPORT) == 0) {
176		vpp = hashvar("PS1=");
177		vps1.next = *vpp;
178		*vpp = &vps1;
179		vps1.text = geteuid() ? "PS1=$ " : "PS1=# ";
180		vps1.flags = VSTRFIXED|VTEXTFIXED;
181	}
182	if ((vppid.flags & VEXPORT) == 0) {
183		fmtstr(ppid, sizeof(ppid), "%d", (int)getppid());
184		setvarsafe("PPID", ppid, 0);
185	}
186}
187
188/*
189 * Safe version of setvar, returns 1 on success 0 on failure.
190 */
191
192int
193setvarsafe(char *name, char *val, int flags)
194{
195	struct jmploc jmploc;
196	struct jmploc *volatile savehandler = handler;
197	int err = 0;
198#if __GNUC__
199	/* Avoid longjmp clobbering */
200	(void) &err;
201#endif
202
203	if (setjmp(jmploc.loc))
204		err = 1;
205	else {
206		handler = &jmploc;
207		setvar(name, val, flags);
208	}
209	handler = savehandler;
210	return err;
211}
212
213/*
214 * Set the value of a variable.  The flags argument is tored with the
215 * flags of the variable.  If val is NULL, the variable is unset.
216 */
217
218void
219setvar(char *name, char *val, int flags)
220{
221	char *p, *q;
222	int len;
223	int namelen;
224	char *nameeq;
225	int isbad;
226
227	isbad = 0;
228	p = name;
229	if (! is_name(*p))
230		isbad = 1;
231	p++;
232	for (;;) {
233		if (! is_in_name(*p)) {
234			if (*p == '\0' || *p == '=')
235				break;
236			isbad = 1;
237		}
238		p++;
239	}
240	namelen = p - name;
241	if (isbad)
242		error("%.*s: bad variable name", namelen, name);
243	len = namelen + 2;		/* 2 is space for '=' and '\0' */
244	if (val == NULL) {
245		flags |= VUNSET;
246	} else {
247		len += strlen(val);
248	}
249	p = nameeq = ckmalloc(len);
250	q = name;
251	while (--namelen >= 0)
252		*p++ = *q++;
253	*p++ = '=';
254	*p = '\0';
255	if (val)
256		scopy(val, p);
257	setvareq(nameeq, flags);
258}
259
260STATIC int
261localevar(char *s)
262{
263	static char *lnames[7] = {
264		"ALL", "COLLATE", "CTYPE", "MONETARY",
265		"NUMERIC", "TIME", NULL
266	};
267	char **ss;
268
269	if (*s != 'L')
270		return 0;
271	if (varequal(s + 1, "ANG"))
272		return 1;
273	if (strncmp(s + 1, "C_", 2) != 0)
274		return 0;
275	for (ss = lnames; *ss ; ss++)
276		if (varequal(s + 3, *ss))
277			return 1;
278	return 0;
279}
280
281/*
282 * Same as setvar except that the variable and value are passed in
283 * the first argument as name=value.  Since the first argument will
284 * be actually stored in the table, it should not be a string that
285 * will go away.
286 */
287
288void
289setvareq(char *s, int flags)
290{
291	struct var *vp, **vpp;
292	int len;
293
294	if (aflag)
295		flags |= VEXPORT;
296	vpp = hashvar(s);
297	for (vp = *vpp ; vp ; vp = vp->next) {
298		if (varequal(s, vp->text)) {
299			if (vp->flags & VREADONLY) {
300				len = strchr(s, '=') - s;
301				error("%.*s: is read only", len, s);
302			}
303			INTOFF;
304
305			if (vp->func && (flags & VNOFUNC) == 0)
306				(*vp->func)(strchr(s, '=') + 1);
307
308			if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
309				ckfree(vp->text);
310
311			vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
312			vp->flags |= flags;
313			vp->text = s;
314
315			/*
316			 * We could roll this to a function, to handle it as
317			 * a regular variable function callback, but why bother?
318			 */
319			if (vp == &vmpath || (vp == &vmail && ! mpathset()))
320				chkmail(1);
321			if ((vp->flags & VEXPORT) && localevar(s)) {
322				putenv(s);
323				(void) setlocale(LC_ALL, "");
324			}
325			INTON;
326			return;
327		}
328	}
329	/* not found */
330	vp = ckmalloc(sizeof (*vp));
331	vp->flags = flags;
332	vp->text = s;
333	vp->next = *vpp;
334	vp->func = NULL;
335	INTOFF;
336	*vpp = vp;
337	if ((vp->flags & VEXPORT) && localevar(s)) {
338		putenv(s);
339		(void) setlocale(LC_ALL, "");
340	}
341	INTON;
342}
343
344
345
346/*
347 * Process a linked list of variable assignments.
348 */
349
350void
351listsetvar(struct strlist *list)
352{
353	struct strlist *lp;
354
355	INTOFF;
356	for (lp = list ; lp ; lp = lp->next) {
357		setvareq(savestr(lp->text), 0);
358	}
359	INTON;
360}
361
362
363
364/*
365 * Find the value of a variable.  Returns NULL if not set.
366 */
367
368char *
369lookupvar(char *name)
370{
371	struct var *v;
372
373	for (v = *hashvar(name) ; v ; v = v->next) {
374		if (varequal(v->text, name)) {
375			if (v->flags & VUNSET)
376				return NULL;
377			return strchr(v->text, '=') + 1;
378		}
379	}
380	return NULL;
381}
382
383
384
385/*
386 * Search the environment of a builtin command.  If the second argument
387 * is nonzero, return the value of a variable even if it hasn't been
388 * exported.
389 */
390
391char *
392bltinlookup(char *name, int doall)
393{
394	struct strlist *sp;
395	struct var *v;
396
397	for (sp = cmdenviron ; sp ; sp = sp->next) {
398		if (varequal(sp->text, name))
399			return strchr(sp->text, '=') + 1;
400	}
401	for (v = *hashvar(name) ; v ; v = v->next) {
402		if (varequal(v->text, name)) {
403			if ((v->flags & VUNSET)
404			 || (!doall && (v->flags & VEXPORT) == 0))
405				return NULL;
406			return strchr(v->text, '=') + 1;
407		}
408	}
409	return NULL;
410}
411
412
413
414/*
415 * Generate a list of exported variables.  This routine is used to construct
416 * the third argument to execve when executing a program.
417 */
418
419char **
420environment(void)
421{
422	int nenv;
423	struct var **vpp;
424	struct var *vp;
425	char **env, **ep;
426
427	nenv = 0;
428	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
429		for (vp = *vpp ; vp ; vp = vp->next)
430			if (vp->flags & VEXPORT)
431				nenv++;
432	}
433	ep = env = stalloc((nenv + 1) * sizeof *env);
434	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
435		for (vp = *vpp ; vp ; vp = vp->next)
436			if (vp->flags & VEXPORT)
437				*ep++ = vp->text;
438	}
439	*ep = NULL;
440	return env;
441}
442
443
444/*
445 * Called when a shell procedure is invoked to clear out nonexported
446 * variables.  It is also necessary to reallocate variables of with
447 * VSTACK set since these are currently allocated on the stack.
448 */
449
450#ifdef mkinit
451MKINIT void shprocvar();
452
453SHELLPROC {
454	shprocvar();
455}
456#endif
457
458void
459shprocvar(void)
460{
461	struct var **vpp;
462	struct var *vp, **prev;
463
464	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
465		for (prev = vpp ; (vp = *prev) != NULL ; ) {
466			if ((vp->flags & VEXPORT) == 0) {
467				*prev = vp->next;
468				if ((vp->flags & VTEXTFIXED) == 0)
469					ckfree(vp->text);
470				if ((vp->flags & VSTRFIXED) == 0)
471					ckfree(vp);
472			} else {
473				if (vp->flags & VSTACK) {
474					vp->text = savestr(vp->text);
475					vp->flags &=~ VSTACK;
476				}
477				prev = &vp->next;
478			}
479		}
480	}
481	initvar();
482}
483
484
485
486/*
487 * Command to list all variables which are set.  Currently this command
488 * is invoked from the set command when the set command is called without
489 * any variables.
490 */
491
492int
493showvarscmd(int argc __unused, char **argv __unused)
494{
495	struct var **vpp;
496	struct var *vp;
497	const char *s;
498
499	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
500		for (vp = *vpp ; vp ; vp = vp->next) {
501			if (vp->flags & VUNSET)
502				continue;
503			for (s = vp->text; *s != '='; s++)
504				out1c(*s);
505			out1c('=');
506			out1qstr(s + 1);
507			out1c('\n');
508		}
509	}
510	return 0;
511}
512
513
514
515/*
516 * The export and readonly commands.
517 */
518
519int
520exportcmd(int argc, char **argv)
521{
522	struct var **vpp;
523	struct var *vp;
524	char *name;
525	char *p;
526	char *cmdname;
527	int ch, values;
528	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
529
530	cmdname = argv[0];
531	optreset = optind = 1;
532	opterr = 0;
533	values = 0;
534	while ((ch = getopt(argc, argv, "p")) != -1) {
535		switch (ch) {
536		case 'p':
537			values = 1;
538			break;
539		case '?':
540		default:
541			error("unknown option: -%c", optopt);
542		}
543	}
544	argc -= optind;
545	argv += optind;
546
547	listsetvar(cmdenviron);
548	if (argc != 0) {
549		while ((name = *argptr++) != NULL) {
550			if ((p = strchr(name, '=')) != NULL) {
551				p++;
552			} else {
553				vpp = hashvar(name);
554				for (vp = *vpp ; vp ; vp = vp->next) {
555					if (varequal(vp->text, name)) {
556
557						vp->flags |= flag;
558						if ((vp->flags & VEXPORT) && localevar(vp->text)) {
559							putenv(vp->text);
560							(void) setlocale(LC_ALL, "");
561						}
562						goto found;
563					}
564				}
565			}
566			setvar(name, p, flag);
567found:;
568		}
569	} else {
570		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
571			for (vp = *vpp ; vp ; vp = vp->next) {
572				if (vp->flags & flag) {
573					if (values) {
574						out1str(cmdname);
575						out1c(' ');
576					}
577					for (p = vp->text ; *p != '=' ; p++)
578						out1c(*p);
579					if (values && !(vp->flags & VUNSET)) {
580						out1c('=');
581						out1qstr(p + 1);
582					}
583					out1c('\n');
584				}
585			}
586		}
587	}
588	return 0;
589}
590
591
592/*
593 * The "local" command.
594 */
595
596int
597localcmd(int argc __unused, char **argv __unused)
598{
599	char *name;
600
601	if (! in_function())
602		error("Not in a function");
603	while ((name = *argptr++) != NULL) {
604		mklocal(name);
605	}
606	return 0;
607}
608
609
610/*
611 * Make a variable a local variable.  When a variable is made local, it's
612 * value and flags are saved in a localvar structure.  The saved values
613 * will be restored when the shell function returns.  We handle the name
614 * "-" as a special case.
615 */
616
617void
618mklocal(char *name)
619{
620	struct localvar *lvp;
621	struct var **vpp;
622	struct var *vp;
623
624	INTOFF;
625	lvp = ckmalloc(sizeof (struct localvar));
626	if (name[0] == '-' && name[1] == '\0') {
627		lvp->text = ckmalloc(sizeof optlist);
628		memcpy(lvp->text, optlist, sizeof optlist);
629		vp = NULL;
630	} else {
631		vpp = hashvar(name);
632		for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next);
633		if (vp == NULL) {
634			if (strchr(name, '='))
635				setvareq(savestr(name), VSTRFIXED);
636			else
637				setvar(name, NULL, VSTRFIXED);
638			vp = *vpp;	/* the new variable */
639			lvp->text = NULL;
640			lvp->flags = VUNSET;
641		} else {
642			lvp->text = vp->text;
643			lvp->flags = vp->flags;
644			vp->flags |= VSTRFIXED|VTEXTFIXED;
645			if (strchr(name, '='))
646				setvareq(savestr(name), 0);
647		}
648	}
649	lvp->vp = vp;
650	lvp->next = localvars;
651	localvars = lvp;
652	INTON;
653}
654
655
656/*
657 * Called after a function returns.
658 */
659
660void
661poplocalvars(void)
662{
663	struct localvar *lvp;
664	struct var *vp;
665
666	while ((lvp = localvars) != NULL) {
667		localvars = lvp->next;
668		vp = lvp->vp;
669		if (vp == NULL) {	/* $- saved */
670			memcpy(optlist, lvp->text, sizeof optlist);
671			ckfree(lvp->text);
672		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
673			(void)unsetvar(vp->text);
674		} else {
675			if ((vp->flags & VTEXTFIXED) == 0)
676				ckfree(vp->text);
677			vp->flags = lvp->flags;
678			vp->text = lvp->text;
679		}
680		ckfree(lvp);
681	}
682}
683
684
685int
686setvarcmd(int argc, char **argv)
687{
688	if (argc <= 2)
689		return unsetcmd(argc, argv);
690	else if (argc == 3)
691		setvar(argv[1], argv[2], 0);
692	else
693		error("List assignment not implemented");
694	return 0;
695}
696
697
698/*
699 * The unset builtin command.  We unset the function before we unset the
700 * variable to allow a function to be unset when there is a readonly variable
701 * with the same name.
702 */
703
704int
705unsetcmd(int argc __unused, char **argv __unused)
706{
707	char **ap;
708	int i;
709	int flg_func = 0;
710	int flg_var = 0;
711	int ret = 0;
712
713	while ((i = nextopt("vf")) != '\0') {
714		if (i == 'f')
715			flg_func = 1;
716		else
717			flg_var = 1;
718	}
719	if (flg_func == 0 && flg_var == 0)
720		flg_var = 1;
721
722	for (ap = argptr; *ap ; ap++) {
723		if (flg_func)
724			ret |= unsetfunc(*ap);
725		if (flg_var)
726			ret |= unsetvar(*ap);
727	}
728	return ret;
729}
730
731
732/*
733 * Unset the specified variable.
734 */
735
736int
737unsetvar(char *s)
738{
739	struct var **vpp;
740	struct var *vp;
741
742	vpp = hashvar(s);
743	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
744		if (varequal(vp->text, s)) {
745			if (vp->flags & VREADONLY)
746				return (1);
747			INTOFF;
748			if (*(strchr(vp->text, '=') + 1) != '\0')
749				setvar(s, nullstr, 0);
750			if ((vp->flags & VEXPORT) && localevar(vp->text)) {
751				unsetenv(s);
752				setlocale(LC_ALL, "");
753			}
754			vp->flags &= ~VEXPORT;
755			vp->flags |= VUNSET;
756			if ((vp->flags & VSTRFIXED) == 0) {
757				if ((vp->flags & VTEXTFIXED) == 0)
758					ckfree(vp->text);
759				*vpp = vp->next;
760				ckfree(vp);
761			}
762			INTON;
763			return (0);
764		}
765	}
766
767	return (1);
768}
769
770
771
772/*
773 * Find the appropriate entry in the hash table from the name.
774 */
775
776STATIC struct var **
777hashvar(char *p)
778{
779	unsigned int hashval;
780
781	hashval = ((unsigned char) *p) << 4;
782	while (*p && *p != '=')
783		hashval += (unsigned char) *p++;
784	return &vartab[hashval % VTABSIZE];
785}
786
787
788
789/*
790 * Returns true if the two strings specify the same varable.  The first
791 * variable name is terminated by '='; the second may be terminated by
792 * either '=' or '\0'.
793 */
794
795STATIC int
796varequal(char *p, char *q)
797{
798	while (*p == *q++) {
799		if (*p++ == '=')
800			return 1;
801	}
802	if (*p == '=' && *(q - 1) == '\0')
803		return 1;
804	return 0;
805}
806