var.c revision 200943 
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 200943 2009-12-24 15:14:22Z 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	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,	VSTRFIXED|VTEXTFIXED|VUNSET,	"HISTSIZE=",
98	  sethistsize },
99#endif
100	{ &vifs,	VSTRFIXED|VTEXTFIXED,		"IFS= \t\n",
101	  NULL },
102	{ &vmail,	VSTRFIXED|VTEXTFIXED|VUNSET,	"MAIL=",
103	  NULL },
104	{ &vmpath,	VSTRFIXED|VTEXTFIXED|VUNSET,	"MAILPATH=",
105	  NULL },
106	{ &vpath,	VSTRFIXED|VTEXTFIXED,		"PATH=" _PATH_DEFPATH,
107	  changepath },
108	{ &vppid,	VSTRFIXED|VTEXTFIXED|VUNSET,	"PPID=",
109	  NULL },
110	/*
111	 * vps1 depends on uid
112	 */
113	{ &vps2,	VSTRFIXED|VTEXTFIXED,		"PS2=> ",
114	  NULL },
115	{ &vps4,	VSTRFIXED|VTEXTFIXED,		"PS4=+ ",
116	  NULL },
117	{ &voptind,	VSTRFIXED|VTEXTFIXED,		"OPTIND=1",
118	  getoptsreset },
119	{ NULL,	0,				NULL,
120	  NULL }
121};
122
123STATIC struct var *vartab[VTABSIZE];
124
125STATIC struct var **hashvar(char *);
126STATIC int varequal(char *, char *);
127STATIC int localevar(char *);
128
129/*
130 * Initialize the variable 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 *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(char *name, char *val, int flags)
219{
220	char *p, *q;
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	p = nameeq = ckmalloc(len);
249	q = name;
250	while (--namelen >= 0)
251		*p++ = *q++;
252	*p++ = '=';
253	*p = '\0';
254	if (val)
255		scopy(val, p);
256	setvareq(nameeq, flags);
257}
258
259STATIC int
260localevar(char *s)
261{
262	static char *lnames[7] = {
263		"ALL", "COLLATE", "CTYPE", "MONETARY",
264		"NUMERIC", "TIME", NULL
265	};
266	char **ss;
267
268	if (*s != 'L')
269		return 0;
270	if (varequal(s + 1, "ANG"))
271		return 1;
272	if (strncmp(s + 1, "C_", 2) != 0)
273		return 0;
274	for (ss = lnames; *ss ; ss++)
275		if (varequal(s + 3, *ss))
276			return 1;
277	return 0;
278}
279
280
281/*
282 * Sets/unsets an environment variable from a pointer that may actually be a
283 * pointer into environ where the string should not be manipulated.
284 */
285static void
286change_env(char *s, int set)
287{
288	char *eqp;
289	char *ss;
290
291	ss = savestr(s);
292	if ((eqp = strchr(ss, '=')) != NULL)
293		*eqp = '\0';
294	if (set && eqp != NULL)
295		(void) setenv(ss, eqp + 1, 1);
296	else
297		(void) unsetenv(ss);
298	ckfree(ss);
299
300	return;
301}
302
303
304/*
305 * Same as setvar except that the variable and value are passed in
306 * the first argument as name=value.  Since the first argument will
307 * be actually stored in the table, it should not be a string that
308 * will go away.
309 */
310
311void
312setvareq(char *s, int flags)
313{
314	struct var *vp, **vpp;
315	int len;
316
317	if (aflag)
318		flags |= VEXPORT;
319	vpp = hashvar(s);
320	for (vp = *vpp ; vp ; vp = vp->next) {
321		if (varequal(s, vp->text)) {
322			if (vp->flags & VREADONLY) {
323				len = strchr(s, '=') - s;
324				error("%.*s: is read only", len, s);
325			}
326			INTOFF;
327
328			if (vp->func && (flags & VNOFUNC) == 0)
329				(*vp->func)(strchr(s, '=') + 1);
330
331			if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
332				ckfree(vp->text);
333
334			vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
335			vp->flags |= flags;
336			vp->text = s;
337
338			/*
339			 * We could roll this to a function, to handle it as
340			 * a regular variable function callback, but why bother?
341			 */
342			if (vp == &vmpath || (vp == &vmail && ! mpathset()))
343				chkmail(1);
344			if ((vp->flags & VEXPORT) && localevar(s)) {
345				change_env(s, 1);
346				(void) setlocale(LC_ALL, "");
347			}
348			INTON;
349			return;
350		}
351	}
352	/* not found */
353	vp = ckmalloc(sizeof (*vp));
354	vp->flags = flags;
355	vp->text = s;
356	vp->next = *vpp;
357	vp->func = NULL;
358	INTOFF;
359	*vpp = vp;
360	if ((vp->flags & VEXPORT) && localevar(s)) {
361		change_env(s, 1);
362		(void) setlocale(LC_ALL, "");
363	}
364	INTON;
365}
366
367
368
369/*
370 * Process a linked list of variable assignments.
371 */
372
373void
374listsetvar(struct strlist *list)
375{
376	struct strlist *lp;
377
378	INTOFF;
379	for (lp = list ; lp ; lp = lp->next) {
380		setvareq(savestr(lp->text), 0);
381	}
382	INTON;
383}
384
385
386
387/*
388 * Find the value of a variable.  Returns NULL if not set.
389 */
390
391char *
392lookupvar(char *name)
393{
394	struct var *v;
395
396	for (v = *hashvar(name) ; v ; v = v->next) {
397		if (varequal(v->text, name)) {
398			if (v->flags & VUNSET)
399				return NULL;
400			return strchr(v->text, '=') + 1;
401		}
402	}
403	return NULL;
404}
405
406
407
408/*
409 * Search the environment of a builtin command.  If the second argument
410 * is nonzero, return the value of a variable even if it hasn't been
411 * exported.
412 */
413
414char *
415bltinlookup(char *name, int doall)
416{
417	struct strlist *sp;
418	struct var *v;
419
420	for (sp = cmdenviron ; sp ; sp = sp->next) {
421		if (varequal(sp->text, name))
422			return strchr(sp->text, '=') + 1;
423	}
424	for (v = *hashvar(name) ; v ; v = v->next) {
425		if (varequal(v->text, name)) {
426			if ((v->flags & VUNSET)
427			 || (!doall && (v->flags & VEXPORT) == 0))
428				return NULL;
429			return strchr(v->text, '=') + 1;
430		}
431	}
432	return NULL;
433}
434
435
436
437/*
438 * Generate a list of exported variables.  This routine is used to construct
439 * the third argument to execve when executing a program.
440 */
441
442char **
443environment(void)
444{
445	int nenv;
446	struct var **vpp;
447	struct var *vp;
448	char **env, **ep;
449
450	nenv = 0;
451	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
452		for (vp = *vpp ; vp ; vp = vp->next)
453			if (vp->flags & VEXPORT)
454				nenv++;
455	}
456	ep = env = stalloc((nenv + 1) * sizeof *env);
457	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
458		for (vp = *vpp ; vp ; vp = vp->next)
459			if (vp->flags & VEXPORT)
460				*ep++ = vp->text;
461	}
462	*ep = NULL;
463	return env;
464}
465
466
467/*
468 * Called when a shell procedure is invoked to clear out nonexported
469 * variables.  It is also necessary to reallocate variables of with
470 * VSTACK set since these are currently allocated on the stack.
471 */
472
473#ifdef mkinit
474MKINIT void shprocvar(void);
475
476SHELLPROC {
477	shprocvar();
478}
479#endif
480
481void
482shprocvar(void)
483{
484	struct var **vpp;
485	struct var *vp, **prev;
486
487	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
488		for (prev = vpp ; (vp = *prev) != NULL ; ) {
489			if ((vp->flags & VEXPORT) == 0) {
490				*prev = vp->next;
491				if ((vp->flags & VTEXTFIXED) == 0)
492					ckfree(vp->text);
493				if ((vp->flags & VSTRFIXED) == 0)
494					ckfree(vp);
495			} else {
496				if (vp->flags & VSTACK) {
497					vp->text = savestr(vp->text);
498					vp->flags &=~ VSTACK;
499				}
500				prev = &vp->next;
501			}
502		}
503	}
504	initvar();
505}
506
507
508static int
509var_compare(const void *a, const void *b)
510{
511	const char *const *sa, *const *sb;
512
513	sa = a;
514	sb = b;
515	/*
516	 * This compares two var=value strings which creates a different
517	 * order from what you would probably expect.  POSIX is somewhat
518	 * ambiguous on what should be sorted exactly.
519	 */
520	return strcoll(*sa, *sb);
521}
522
523
524/*
525 * Command to list all variables which are set.  Currently this command
526 * is invoked from the set command when the set command is called without
527 * any variables.
528 */
529
530int
531showvarscmd(int argc __unused, char **argv __unused)
532{
533	struct var **vpp;
534	struct var *vp;
535	const char *s;
536	const char **vars;
537	int i, n;
538
539	/*
540	 * POSIX requires us to sort the variables.
541	 */
542	n = 0;
543	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
544		for (vp = *vpp; vp; vp = vp->next) {
545			if (!(vp->flags & VUNSET))
546				n++;
547		}
548	}
549
550	INTON;
551	vars = ckmalloc(n * sizeof(*vars));
552	i = 0;
553	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
554		for (vp = *vpp; vp; vp = vp->next) {
555			if (!(vp->flags & VUNSET))
556				vars[i++] = vp->text;
557		}
558	}
559
560	qsort(vars, n, sizeof(*vars), var_compare);
561	for (i = 0; i < n; i++) {
562		for (s = vars[i]; *s != '='; s++)
563			out1c(*s);
564		out1c('=');
565		out1qstr(s + 1);
566		out1c('\n');
567	}
568	ckfree(vars);
569	INTOFF;
570
571	return 0;
572}
573
574
575
576/*
577 * The export and readonly commands.
578 */
579
580int
581exportcmd(int argc, char **argv)
582{
583	struct var **vpp;
584	struct var *vp;
585	char *name;
586	char *p;
587	char *cmdname;
588	int ch, values;
589	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
590
591	cmdname = argv[0];
592	optreset = optind = 1;
593	opterr = 0;
594	values = 0;
595	while ((ch = getopt(argc, argv, "p")) != -1) {
596		switch (ch) {
597		case 'p':
598			values = 1;
599			break;
600		case '?':
601		default:
602			error("unknown option: -%c", optopt);
603		}
604	}
605	argc -= optind;
606	argv += optind;
607
608	if (values && argc != 0)
609		error("-p requires no arguments");
610	if (argc != 0) {
611		while ((name = *argv++) != NULL) {
612			if ((p = strchr(name, '=')) != NULL) {
613				p++;
614			} else {
615				vpp = hashvar(name);
616				for (vp = *vpp ; vp ; vp = vp->next) {
617					if (varequal(vp->text, name)) {
618
619						vp->flags |= flag;
620						if ((vp->flags & VEXPORT) && localevar(vp->text)) {
621							change_env(vp->text, 1);
622							(void) setlocale(LC_ALL, "");
623						}
624						goto found;
625					}
626				}
627			}
628			setvar(name, p, flag);
629found:;
630		}
631	} else {
632		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
633			for (vp = *vpp ; vp ; vp = vp->next) {
634				if (vp->flags & flag) {
635					if (values) {
636						out1str(cmdname);
637						out1c(' ');
638					}
639					for (p = vp->text ; *p != '=' ; p++)
640						out1c(*p);
641					if (values && !(vp->flags & VUNSET)) {
642						out1c('=');
643						out1qstr(p + 1);
644					}
645					out1c('\n');
646				}
647			}
648		}
649	}
650	return 0;
651}
652
653
654/*
655 * The "local" command.
656 */
657
658int
659localcmd(int argc __unused, char **argv __unused)
660{
661	char *name;
662
663	if (! in_function())
664		error("Not in a function");
665	while ((name = *argptr++) != NULL) {
666		mklocal(name);
667	}
668	return 0;
669}
670
671
672/*
673 * Make a variable a local variable.  When a variable is made local, it's
674 * value and flags are saved in a localvar structure.  The saved values
675 * will be restored when the shell function returns.  We handle the name
676 * "-" as a special case.
677 */
678
679void
680mklocal(char *name)
681{
682	struct localvar *lvp;
683	struct var **vpp;
684	struct var *vp;
685
686	INTOFF;
687	lvp = ckmalloc(sizeof (struct localvar));
688	if (name[0] == '-' && name[1] == '\0') {
689		lvp->text = ckmalloc(sizeof optlist);
690		memcpy(lvp->text, optlist, sizeof optlist);
691		vp = NULL;
692	} else {
693		vpp = hashvar(name);
694		for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next);
695		if (vp == NULL) {
696			if (strchr(name, '='))
697				setvareq(savestr(name), VSTRFIXED);
698			else
699				setvar(name, NULL, VSTRFIXED);
700			vp = *vpp;	/* the new variable */
701			lvp->text = NULL;
702			lvp->flags = VUNSET;
703		} else {
704			lvp->text = vp->text;
705			lvp->flags = vp->flags;
706			vp->flags |= VSTRFIXED|VTEXTFIXED;
707			if (strchr(name, '='))
708				setvareq(savestr(name), 0);
709		}
710	}
711	lvp->vp = vp;
712	lvp->next = localvars;
713	localvars = lvp;
714	INTON;
715}
716
717
718/*
719 * Called after a function returns.
720 */
721
722void
723poplocalvars(void)
724{
725	struct localvar *lvp;
726	struct var *vp;
727
728	while ((lvp = localvars) != NULL) {
729		localvars = lvp->next;
730		vp = lvp->vp;
731		if (vp == NULL) {	/* $- saved */
732			memcpy(optlist, lvp->text, sizeof optlist);
733			ckfree(lvp->text);
734		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
735			(void)unsetvar(vp->text);
736		} else {
737			if ((vp->flags & VTEXTFIXED) == 0)
738				ckfree(vp->text);
739			vp->flags = lvp->flags;
740			vp->text = lvp->text;
741		}
742		ckfree(lvp);
743	}
744}
745
746
747int
748setvarcmd(int argc, char **argv)
749{
750	if (argc <= 2)
751		return unsetcmd(argc, argv);
752	else if (argc == 3)
753		setvar(argv[1], argv[2], 0);
754	else
755		error("List assignment not implemented");
756	return 0;
757}
758
759
760/*
761 * The unset builtin command.  We unset the function before we unset the
762 * variable to allow a function to be unset when there is a readonly variable
763 * with the same name.
764 */
765
766int
767unsetcmd(int argc __unused, char **argv __unused)
768{
769	char **ap;
770	int i;
771	int flg_func = 0;
772	int flg_var = 0;
773	int ret = 0;
774
775	while ((i = nextopt("vf")) != '\0') {
776		if (i == 'f')
777			flg_func = 1;
778		else
779			flg_var = 1;
780	}
781	if (flg_func == 0 && flg_var == 0)
782		flg_var = 1;
783
784	for (ap = argptr; *ap ; ap++) {
785		if (flg_func)
786			ret |= unsetfunc(*ap);
787		if (flg_var)
788			ret |= unsetvar(*ap);
789	}
790	return ret;
791}
792
793
794/*
795 * Unset the specified variable.
796 */
797
798int
799unsetvar(char *s)
800{
801	struct var **vpp;
802	struct var *vp;
803
804	vpp = hashvar(s);
805	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
806		if (varequal(vp->text, s)) {
807			if (vp->flags & VREADONLY)
808				return (1);
809			INTOFF;
810			if (*(strchr(vp->text, '=') + 1) != '\0')
811				setvar(s, nullstr, 0);
812			if ((vp->flags & VEXPORT) && localevar(vp->text)) {
813				change_env(s, 0);
814				setlocale(LC_ALL, "");
815			}
816			vp->flags &= ~VEXPORT;
817			vp->flags |= VUNSET;
818			if ((vp->flags & VSTRFIXED) == 0) {
819				if ((vp->flags & VTEXTFIXED) == 0)
820					ckfree(vp->text);
821				*vpp = vp->next;
822				ckfree(vp);
823			}
824			INTON;
825			return (0);
826		}
827	}
828
829	return (0);
830}
831
832
833
834/*
835 * Find the appropriate entry in the hash table from the name.
836 */
837
838STATIC struct var **
839hashvar(char *p)
840{
841	unsigned int hashval;
842
843	hashval = ((unsigned char) *p) << 4;
844	while (*p && *p != '=')
845		hashval += (unsigned char) *p++;
846	return &vartab[hashval % VTABSIZE];
847}
848
849
850
851/*
852 * Returns true if the two strings specify the same varable.  The first
853 * variable name is terminated by '='; the second may be terminated by
854 * either '=' or '\0'.
855 */
856
857STATIC int
858varequal(char *p, char *q)
859{
860	while (*p == *q++) {
861		if (*p++ == '=')
862			return 1;
863	}
864	if (*p == '=' && *(q - 1) == '\0')
865		return 1;
866	return 0;
867}
868