var.c revision 201056 
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 201056 2009-12-27 18:32:44Z 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
51#include "shell.h"
52#include "output.h"
53#include "expand.h"
54#include "nodes.h"	/* for other headers */
55#include "eval.h"	/* defines cmdenviron */
56#include "exec.h"
57#include "syntax.h"
58#include "options.h"
59#include "mail.h"
60#include "var.h"
61#include "memalloc.h"
62#include "error.h"
63#include "mystring.h"
64#include "parser.h"
65#ifndef NO_HISTORY
66#include "myhistedit.h"
67#endif
68
69
70#define VTABSIZE 39
71
72
73struct varinit {
74	struct var *var;
75	int flags;
76	const char *text;
77	void (*func)(const char *);
78};
79
80
81#ifndef NO_HISTORY
82struct var vhistsize;
83#endif
84struct var vifs;
85struct var vmail;
86struct var vmpath;
87struct var vpath;
88struct var vppid;
89struct var vps1;
90struct var vps2;
91struct var vps4;
92struct var vvers;
93STATIC struct var voptind;
94
95STATIC const struct varinit varinit[] = {
96#ifndef NO_HISTORY
97	{ &vhistsize,	VUNSET,				"HISTSIZE=",
98	  sethistsize },
99#endif
100	{ &vifs,	0,				"IFS= \t\n",
101	  NULL },
102	{ &vmail,	VUNSET,				"MAIL=",
103	  NULL },
104	{ &vmpath,	VUNSET,				"MAILPATH=",
105	  NULL },
106	{ &vpath,	0,				"PATH=" _PATH_DEFPATH,
107	  changepath },
108	{ &vppid,	VUNSET,				"PPID=",
109	  NULL },
110	/*
111	 * vps1 depends on uid
112	 */
113	{ &vps2,	0,				"PS2=> ",
114	  NULL },
115	{ &vps4,	0,				"PS4=+ ",
116	  NULL },
117	{ &voptind,	0,				"OPTIND=1",
118	  getoptsreset },
119	{ NULL,	0,				NULL,
120	  NULL }
121};
122
123STATIC struct var *vartab[VTABSIZE];
124
125STATIC struct var **hashvar(const char *);
126STATIC int varequal(const char *, const char *);
127STATIC int localevar(const char *);
128
129/*
130 * Initialize the variable symbol tables and import the environment.
131 */
132
133#ifdef mkinit
134INCLUDE "var.h"
135MKINIT char **environ;
136INIT {
137	char **envp;
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 = __DECONST(char *, ip->text);
168			vp->flags = ip->flags | VSTRFIXED | VTEXTFIXED;
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 = __DECONST(char *, 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(const char *name, const char *val, int flags)
194{
195	struct jmploc jmploc;
196	struct jmploc *const savehandler = handler;
197	int err = 0;
198	int inton;
199
200	inton = is_int_on();
201	if (setjmp(jmploc.loc))
202		err = 1;
203	else {
204		handler = &jmploc;
205		setvar(name, val, flags);
206	}
207	handler = savehandler;
208	SETINTON(inton);
209	return err;
210}
211
212/*
213 * Set the value of a variable.  The flags argument is stored with the
214 * flags of the variable.  If val is NULL, the variable is unset.
215 */
216
217void
218setvar(const char *name, const char *val, int flags)
219{
220	const char *p;
221	int len;
222	int namelen;
223	char *nameeq;
224	int isbad;
225
226	isbad = 0;
227	p = name;
228	if (! is_name(*p))
229		isbad = 1;
230	p++;
231	for (;;) {
232		if (! is_in_name(*p)) {
233			if (*p == '\0' || *p == '=')
234				break;
235			isbad = 1;
236		}
237		p++;
238	}
239	namelen = p - name;
240	if (isbad)
241		error("%.*s: bad variable name", namelen, name);
242	len = namelen + 2;		/* 2 is space for '=' and '\0' */
243	if (val == NULL) {
244		flags |= VUNSET;
245	} else {
246		len += strlen(val);
247	}
248	nameeq = ckmalloc(len);
249	memcpy(nameeq, name, namelen);
250	nameeq[namelen] = '=';
251	if (val)
252		scopy(val, nameeq + namelen + 1);
253	else
254		nameeq[namelen + 1] = '\0';
255	setvareq(nameeq, flags);
256}
257
258STATIC int
259localevar(const char *s)
260{
261	static const char *lnames[7] = {
262		"ALL", "COLLATE", "CTYPE", "MONETARY",
263		"NUMERIC", "TIME", NULL
264	};
265	const char **ss;
266
267	if (*s != 'L')
268		return 0;
269	if (varequal(s + 1, "ANG"))
270		return 1;
271	if (strncmp(s + 1, "C_", 2) != 0)
272		return 0;
273	for (ss = lnames; *ss ; ss++)
274		if (varequal(s + 3, *ss))
275			return 1;
276	return 0;
277}
278
279
280/*
281 * Sets/unsets an environment variable from a pointer that may actually be a
282 * pointer into environ where the string should not be manipulated.
283 */
284static void
285change_env(const char *s, int set)
286{
287	char *eqp;
288	char *ss;
289
290	ss = savestr(s);
291	if ((eqp = strchr(ss, '=')) != NULL)
292		*eqp = '\0';
293	if (set && eqp != NULL)
294		(void) setenv(ss, eqp + 1, 1);
295	else
296		(void) unsetenv(ss);
297	ckfree(ss);
298
299	return;
300}
301
302
303/*
304 * Same as setvar except that the variable and value are passed in
305 * the first argument as name=value.  Since the first argument will
306 * be actually stored in the table, it should not be a string that
307 * will go away.
308 */
309
310void
311setvareq(char *s, int flags)
312{
313	struct var *vp, **vpp;
314	int len;
315
316	if (aflag)
317		flags |= VEXPORT;
318	vpp = hashvar(s);
319	for (vp = *vpp ; vp ; vp = vp->next) {
320		if (varequal(s, vp->text)) {
321			if (vp->flags & VREADONLY) {
322				len = strchr(s, '=') - s;
323				error("%.*s: is read only", len, s);
324			}
325			INTOFF;
326
327			if (vp->func && (flags & VNOFUNC) == 0)
328				(*vp->func)(strchr(s, '=') + 1);
329
330			if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
331				ckfree(vp->text);
332
333			vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
334			vp->flags |= flags;
335			vp->text = s;
336
337			/*
338			 * We could roll this to a function, to handle it as
339			 * a regular variable function callback, but why bother?
340			 */
341			if (vp == &vmpath || (vp == &vmail && ! mpathset()))
342				chkmail(1);
343			if ((vp->flags & VEXPORT) && localevar(s)) {
344				change_env(s, 1);
345				(void) setlocale(LC_ALL, "");
346			}
347			INTON;
348			return;
349		}
350	}
351	/* not found */
352	vp = ckmalloc(sizeof (*vp));
353	vp->flags = flags;
354	vp->text = s;
355	vp->next = *vpp;
356	vp->func = NULL;
357	INTOFF;
358	*vpp = vp;
359	if ((vp->flags & VEXPORT) && localevar(s)) {
360		change_env(s, 1);
361		(void) setlocale(LC_ALL, "");
362	}
363	INTON;
364}
365
366
367
368/*
369 * Process a linked list of variable assignments.
370 */
371
372void
373listsetvar(struct strlist *list)
374{
375	struct strlist *lp;
376
377	INTOFF;
378	for (lp = list ; lp ; lp = lp->next) {
379		setvareq(savestr(lp->text), 0);
380	}
381	INTON;
382}
383
384
385
386/*
387 * Find the value of a variable.  Returns NULL if not set.
388 */
389
390char *
391lookupvar(const char *name)
392{
393	struct var *v;
394
395	for (v = *hashvar(name) ; v ; v = v->next) {
396		if (varequal(v->text, name)) {
397			if (v->flags & VUNSET)
398				return NULL;
399			return strchr(v->text, '=') + 1;
400		}
401	}
402	return NULL;
403}
404
405
406
407/*
408 * Search the environment of a builtin command.  If the second argument
409 * is nonzero, return the value of a variable even if it hasn't been
410 * exported.
411 */
412
413char *
414bltinlookup(const char *name, int doall)
415{
416	struct strlist *sp;
417	struct var *v;
418
419	for (sp = cmdenviron ; sp ; sp = sp->next) {
420		if (varequal(sp->text, name))
421			return strchr(sp->text, '=') + 1;
422	}
423	for (v = *hashvar(name) ; v ; v = v->next) {
424		if (varequal(v->text, name)) {
425			if ((v->flags & VUNSET)
426			 || (!doall && (v->flags & VEXPORT) == 0))
427				return NULL;
428			return strchr(v->text, '=') + 1;
429		}
430	}
431	return NULL;
432}
433
434
435
436/*
437 * Generate a list of exported variables.  This routine is used to construct
438 * the third argument to execve when executing a program.
439 */
440
441char **
442environment(void)
443{
444	int nenv;
445	struct var **vpp;
446	struct var *vp;
447	char **env, **ep;
448
449	nenv = 0;
450	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
451		for (vp = *vpp ; vp ; vp = vp->next)
452			if (vp->flags & VEXPORT)
453				nenv++;
454	}
455	ep = env = stalloc((nenv + 1) * sizeof *env);
456	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
457		for (vp = *vpp ; vp ; vp = vp->next)
458			if (vp->flags & VEXPORT)
459				*ep++ = vp->text;
460	}
461	*ep = NULL;
462	return env;
463}
464
465
466/*
467 * Called when a shell procedure is invoked to clear out nonexported
468 * variables.  It is also necessary to reallocate variables of with
469 * VSTACK set since these are currently allocated on the stack.
470 */
471
472MKINIT void shprocvar(void);
473
474#ifdef mkinit
475SHELLPROC {
476	shprocvar();
477}
478#endif
479
480void
481shprocvar(void)
482{
483	struct var **vpp;
484	struct var *vp, **prev;
485
486	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
487		for (prev = vpp ; (vp = *prev) != NULL ; ) {
488			if ((vp->flags & VEXPORT) == 0) {
489				*prev = vp->next;
490				if ((vp->flags & VTEXTFIXED) == 0)
491					ckfree(vp->text);
492				if ((vp->flags & VSTRFIXED) == 0)
493					ckfree(vp);
494			} else {
495				if (vp->flags & VSTACK) {
496					vp->text = savestr(vp->text);
497					vp->flags &=~ VSTACK;
498				}
499				prev = &vp->next;
500			}
501		}
502	}
503	initvar();
504}
505
506
507static int
508var_compare(const void *a, const void *b)
509{
510	const char *const *sa, *const *sb;
511
512	sa = a;
513	sb = b;
514	/*
515	 * This compares two var=value strings which creates a different
516	 * order from what you would probably expect.  POSIX is somewhat
517	 * ambiguous on what should be sorted exactly.
518	 */
519	return strcoll(*sa, *sb);
520}
521
522
523/*
524 * Command to list all variables which are set.  Currently this command
525 * is invoked from the set command when the set command is called without
526 * any variables.
527 */
528
529int
530showvarscmd(int argc __unused, char **argv __unused)
531{
532	struct var **vpp;
533	struct var *vp;
534	const char *s;
535	const char **vars;
536	int i, n;
537
538	/*
539	 * POSIX requires us to sort the variables.
540	 */
541	n = 0;
542	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
543		for (vp = *vpp; vp; vp = vp->next) {
544			if (!(vp->flags & VUNSET))
545				n++;
546		}
547	}
548
549	INTON;
550	vars = ckmalloc(n * sizeof(*vars));
551	i = 0;
552	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
553		for (vp = *vpp; vp; vp = vp->next) {
554			if (!(vp->flags & VUNSET))
555				vars[i++] = vp->text;
556		}
557	}
558
559	qsort(vars, n, sizeof(*vars), var_compare);
560	for (i = 0; i < n; i++) {
561		for (s = vars[i]; *s != '='; s++)
562			out1c(*s);
563		out1c('=');
564		out1qstr(s + 1);
565		out1c('\n');
566	}
567	ckfree(vars);
568	INTOFF;
569
570	return 0;
571}
572
573
574
575/*
576 * The export and readonly commands.
577 */
578
579int
580exportcmd(int argc, char **argv)
581{
582	struct var **vpp;
583	struct var *vp;
584	char *name;
585	char *p;
586	char *cmdname;
587	int ch, values;
588	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
589
590	cmdname = argv[0];
591	optreset = optind = 1;
592	opterr = 0;
593	values = 0;
594	while ((ch = getopt(argc, argv, "p")) != -1) {
595		switch (ch) {
596		case 'p':
597			values = 1;
598			break;
599		case '?':
600		default:
601			error("unknown option: -%c", optopt);
602		}
603	}
604	argc -= optind;
605	argv += optind;
606
607	if (values && argc != 0)
608		error("-p requires no arguments");
609	if (argc != 0) {
610		while ((name = *argv++) != NULL) {
611			if ((p = strchr(name, '=')) != NULL) {
612				p++;
613			} else {
614				vpp = hashvar(name);
615				for (vp = *vpp ; vp ; vp = vp->next) {
616					if (varequal(vp->text, name)) {
617
618						vp->flags |= flag;
619						if ((vp->flags & VEXPORT) && localevar(vp->text)) {
620							change_env(vp->text, 1);
621							(void) setlocale(LC_ALL, "");
622						}
623						goto found;
624					}
625				}
626			}
627			setvar(name, p, flag);
628found:;
629		}
630	} else {
631		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
632			for (vp = *vpp ; vp ; vp = vp->next) {
633				if (vp->flags & flag) {
634					if (values) {
635						out1str(cmdname);
636						out1c(' ');
637					}
638					for (p = vp->text ; *p != '=' ; p++)
639						out1c(*p);
640					if (values && !(vp->flags & VUNSET)) {
641						out1c('=');
642						out1qstr(p + 1);
643					}
644					out1c('\n');
645				}
646			}
647		}
648	}
649	return 0;
650}
651
652
653/*
654 * The "local" command.
655 */
656
657int
658localcmd(int argc __unused, char **argv __unused)
659{
660	char *name;
661
662	if (! in_function())
663		error("Not in a function");
664	while ((name = *argptr++) != NULL) {
665		mklocal(name);
666	}
667	return 0;
668}
669
670
671/*
672 * Make a variable a local variable.  When a variable is made local, it's
673 * value and flags are saved in a localvar structure.  The saved values
674 * will be restored when the shell function returns.  We handle the name
675 * "-" as a special case.
676 */
677
678void
679mklocal(char *name)
680{
681	struct localvar *lvp;
682	struct var **vpp;
683	struct var *vp;
684
685	INTOFF;
686	lvp = ckmalloc(sizeof (struct localvar));
687	if (name[0] == '-' && name[1] == '\0') {
688		lvp->text = ckmalloc(sizeof optlist);
689		memcpy(lvp->text, optlist, sizeof optlist);
690		vp = NULL;
691	} else {
692		vpp = hashvar(name);
693		for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next);
694		if (vp == NULL) {
695			if (strchr(name, '='))
696				setvareq(savestr(name), VSTRFIXED);
697			else
698				setvar(name, NULL, VSTRFIXED);
699			vp = *vpp;	/* the new variable */
700			lvp->text = NULL;
701			lvp->flags = VUNSET;
702		} else {
703			lvp->text = vp->text;
704			lvp->flags = vp->flags;
705			vp->flags |= VSTRFIXED|VTEXTFIXED;
706			if (strchr(name, '='))
707				setvareq(savestr(name), 0);
708		}
709	}
710	lvp->vp = vp;
711	lvp->next = localvars;
712	localvars = lvp;
713	INTON;
714}
715
716
717/*
718 * Called after a function returns.
719 */
720
721void
722poplocalvars(void)
723{
724	struct localvar *lvp;
725	struct var *vp;
726
727	while ((lvp = localvars) != NULL) {
728		localvars = lvp->next;
729		vp = lvp->vp;
730		if (vp == NULL) {	/* $- saved */
731			memcpy(optlist, lvp->text, sizeof optlist);
732			ckfree(lvp->text);
733		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
734			(void)unsetvar(vp->text);
735		} else {
736			if ((vp->flags & VTEXTFIXED) == 0)
737				ckfree(vp->text);
738			vp->flags = lvp->flags;
739			vp->text = lvp->text;
740		}
741		ckfree(lvp);
742	}
743}
744
745
746int
747setvarcmd(int argc, char **argv)
748{
749	if (argc <= 2)
750		return unsetcmd(argc, argv);
751	else if (argc == 3)
752		setvar(argv[1], argv[2], 0);
753	else
754		error("List assignment not implemented");
755	return 0;
756}
757
758
759/*
760 * The unset builtin command.  We unset the function before we unset the
761 * variable to allow a function to be unset when there is a readonly variable
762 * with the same name.
763 */
764
765int
766unsetcmd(int argc __unused, char **argv __unused)
767{
768	char **ap;
769	int i;
770	int flg_func = 0;
771	int flg_var = 0;
772	int ret = 0;
773
774	while ((i = nextopt("vf")) != '\0') {
775		if (i == 'f')
776			flg_func = 1;
777		else
778			flg_var = 1;
779	}
780	if (flg_func == 0 && flg_var == 0)
781		flg_var = 1;
782
783	for (ap = argptr; *ap ; ap++) {
784		if (flg_func)
785			ret |= unsetfunc(*ap);
786		if (flg_var)
787			ret |= unsetvar(*ap);
788	}
789	return ret;
790}
791
792
793/*
794 * Unset the specified variable.
795 */
796
797int
798unsetvar(const char *s)
799{
800	struct var **vpp;
801	struct var *vp;
802
803	vpp = hashvar(s);
804	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
805		if (varequal(vp->text, s)) {
806			if (vp->flags & VREADONLY)
807				return (1);
808			INTOFF;
809			if (*(strchr(vp->text, '=') + 1) != '\0')
810				setvar(s, nullstr, 0);
811			if ((vp->flags & VEXPORT) && localevar(vp->text)) {
812				change_env(s, 0);
813				setlocale(LC_ALL, "");
814			}
815			vp->flags &= ~VEXPORT;
816			vp->flags |= VUNSET;
817			if ((vp->flags & VSTRFIXED) == 0) {
818				if ((vp->flags & VTEXTFIXED) == 0)
819					ckfree(vp->text);
820				*vpp = vp->next;
821				ckfree(vp);
822			}
823			INTON;
824			return (0);
825		}
826	}
827
828	return (0);
829}
830
831
832
833/*
834 * Find the appropriate entry in the hash table from the name.
835 */
836
837STATIC struct var **
838hashvar(const char *p)
839{
840	unsigned int hashval;
841
842	hashval = ((unsigned char) *p) << 4;
843	while (*p && *p != '=')
844		hashval += (unsigned char) *p++;
845	return &vartab[hashval % VTABSIZE];
846}
847
848
849
850/*
851 * Returns true if the two strings specify the same varable.  The first
852 * variable name is terminated by '='; the second may be terminated by
853 * either '=' or '\0'.
854 */
855
856STATIC int
857varequal(const char *p, const char *q)
858{
859	while (*p == *q++) {
860		if (*p++ == '=')
861			return 1;
862	}
863	if (*p == '=' && *(q - 1) == '\0')
864		return 1;
865	return 0;
866}
867