var.c revision 194765 
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 194765 2009-06-23 20:45:12Z 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
199	if (setjmp(jmploc.loc))
200		err = 1;
201	else {
202		handler = &jmploc;
203		setvar(name, val, flags);
204	}
205	handler = savehandler;
206	return err;
207}
208
209/*
210 * Set the value of a variable.  The flags argument is stored with the
211 * flags of the variable.  If val is NULL, the variable is unset.
212 */
213
214void
215setvar(char *name, char *val, int flags)
216{
217	char *p, *q;
218	int len;
219	int namelen;
220	char *nameeq;
221	int isbad;
222
223	isbad = 0;
224	p = name;
225	if (! is_name(*p))
226		isbad = 1;
227	p++;
228	for (;;) {
229		if (! is_in_name(*p)) {
230			if (*p == '\0' || *p == '=')
231				break;
232			isbad = 1;
233		}
234		p++;
235	}
236	namelen = p - name;
237	if (isbad)
238		error("%.*s: bad variable name", namelen, name);
239	len = namelen + 2;		/* 2 is space for '=' and '\0' */
240	if (val == NULL) {
241		flags |= VUNSET;
242	} else {
243		len += strlen(val);
244	}
245	p = nameeq = ckmalloc(len);
246	q = name;
247	while (--namelen >= 0)
248		*p++ = *q++;
249	*p++ = '=';
250	*p = '\0';
251	if (val)
252		scopy(val, p);
253	setvareq(nameeq, flags);
254}
255
256STATIC int
257localevar(char *s)
258{
259	static char *lnames[7] = {
260		"ALL", "COLLATE", "CTYPE", "MONETARY",
261		"NUMERIC", "TIME", NULL
262	};
263	char **ss;
264
265	if (*s != 'L')
266		return 0;
267	if (varequal(s + 1, "ANG"))
268		return 1;
269	if (strncmp(s + 1, "C_", 2) != 0)
270		return 0;
271	for (ss = lnames; *ss ; ss++)
272		if (varequal(s + 3, *ss))
273			return 1;
274	return 0;
275}
276
277
278/*
279 * Sets/unsets an environment variable from a pointer that may actually be a
280 * pointer into environ where the string should not be manipulated.
281 */
282static void
283change_env(char *s, int set)
284{
285	char *eqp;
286	char *ss;
287
288	ss = savestr(s);
289	if ((eqp = strchr(ss, '=')) != NULL)
290		*eqp = '\0';
291	if (set && eqp != NULL)
292		(void) setenv(ss, eqp + 1, 1);
293	else
294		(void) unsetenv(ss);
295	ckfree(ss);
296
297	return;
298}
299
300
301/*
302 * Same as setvar except that the variable and value are passed in
303 * the first argument as name=value.  Since the first argument will
304 * be actually stored in the table, it should not be a string that
305 * will go away.
306 */
307
308void
309setvareq(char *s, int flags)
310{
311	struct var *vp, **vpp;
312	int len;
313
314	if (aflag)
315		flags |= VEXPORT;
316	vpp = hashvar(s);
317	for (vp = *vpp ; vp ; vp = vp->next) {
318		if (varequal(s, vp->text)) {
319			if (vp->flags & VREADONLY) {
320				len = strchr(s, '=') - s;
321				error("%.*s: is read only", len, s);
322			}
323			INTOFF;
324
325			if (vp->func && (flags & VNOFUNC) == 0)
326				(*vp->func)(strchr(s, '=') + 1);
327
328			if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
329				ckfree(vp->text);
330
331			vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
332			vp->flags |= flags;
333			vp->text = s;
334
335			/*
336			 * We could roll this to a function, to handle it as
337			 * a regular variable function callback, but why bother?
338			 */
339			if (vp == &vmpath || (vp == &vmail && ! mpathset()))
340				chkmail(1);
341			if ((vp->flags & VEXPORT) && localevar(s)) {
342				change_env(s, 1);
343				(void) setlocale(LC_ALL, "");
344			}
345			INTON;
346			return;
347		}
348	}
349	/* not found */
350	vp = ckmalloc(sizeof (*vp));
351	vp->flags = flags;
352	vp->text = s;
353	vp->next = *vpp;
354	vp->func = NULL;
355	INTOFF;
356	*vpp = vp;
357	if ((vp->flags & VEXPORT) && localevar(s)) {
358		change_env(s, 1);
359		(void) setlocale(LC_ALL, "");
360	}
361	INTON;
362}
363
364
365
366/*
367 * Process a linked list of variable assignments.
368 */
369
370void
371listsetvar(struct strlist *list)
372{
373	struct strlist *lp;
374
375	INTOFF;
376	for (lp = list ; lp ; lp = lp->next) {
377		setvareq(savestr(lp->text), 0);
378	}
379	INTON;
380}
381
382
383
384/*
385 * Find the value of a variable.  Returns NULL if not set.
386 */
387
388char *
389lookupvar(char *name)
390{
391	struct var *v;
392
393	for (v = *hashvar(name) ; v ; v = v->next) {
394		if (varequal(v->text, name)) {
395			if (v->flags & VUNSET)
396				return NULL;
397			return strchr(v->text, '=') + 1;
398		}
399	}
400	return NULL;
401}
402
403
404
405/*
406 * Search the environment of a builtin command.  If the second argument
407 * is nonzero, return the value of a variable even if it hasn't been
408 * exported.
409 */
410
411char *
412bltinlookup(char *name, int doall)
413{
414	struct strlist *sp;
415	struct var *v;
416
417	for (sp = cmdenviron ; sp ; sp = sp->next) {
418		if (varequal(sp->text, name))
419			return strchr(sp->text, '=') + 1;
420	}
421	for (v = *hashvar(name) ; v ; v = v->next) {
422		if (varequal(v->text, name)) {
423			if ((v->flags & VUNSET)
424			 || (!doall && (v->flags & VEXPORT) == 0))
425				return NULL;
426			return strchr(v->text, '=') + 1;
427		}
428	}
429	return NULL;
430}
431
432
433
434/*
435 * Generate a list of exported variables.  This routine is used to construct
436 * the third argument to execve when executing a program.
437 */
438
439char **
440environment(void)
441{
442	int nenv;
443	struct var **vpp;
444	struct var *vp;
445	char **env, **ep;
446
447	nenv = 0;
448	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
449		for (vp = *vpp ; vp ; vp = vp->next)
450			if (vp->flags & VEXPORT)
451				nenv++;
452	}
453	ep = env = stalloc((nenv + 1) * sizeof *env);
454	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
455		for (vp = *vpp ; vp ; vp = vp->next)
456			if (vp->flags & VEXPORT)
457				*ep++ = vp->text;
458	}
459	*ep = NULL;
460	return env;
461}
462
463
464/*
465 * Called when a shell procedure is invoked to clear out nonexported
466 * variables.  It is also necessary to reallocate variables of with
467 * VSTACK set since these are currently allocated on the stack.
468 */
469
470#ifdef mkinit
471MKINIT void shprocvar(void);
472
473SHELLPROC {
474	shprocvar();
475}
476#endif
477
478void
479shprocvar(void)
480{
481	struct var **vpp;
482	struct var *vp, **prev;
483
484	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
485		for (prev = vpp ; (vp = *prev) != NULL ; ) {
486			if ((vp->flags & VEXPORT) == 0) {
487				*prev = vp->next;
488				if ((vp->flags & VTEXTFIXED) == 0)
489					ckfree(vp->text);
490				if ((vp->flags & VSTRFIXED) == 0)
491					ckfree(vp);
492			} else {
493				if (vp->flags & VSTACK) {
494					vp->text = savestr(vp->text);
495					vp->flags &=~ VSTACK;
496				}
497				prev = &vp->next;
498			}
499		}
500	}
501	initvar();
502}
503
504
505static int
506var_compare(const void *a, const void *b)
507{
508	const char *const *sa, *const *sb;
509
510	sa = a;
511	sb = b;
512	/*
513	 * This compares two var=value strings which creates a different
514	 * order from what you would probably expect.  POSIX is somewhat
515	 * ambiguous on what should be sorted exactly.
516	 */
517	return strcoll(*sa, *sb);
518}
519
520
521/*
522 * Command to list all variables which are set.  Currently this command
523 * is invoked from the set command when the set command is called without
524 * any variables.
525 */
526
527int
528showvarscmd(int argc __unused, char **argv __unused)
529{
530	struct var **vpp;
531	struct var *vp;
532	const char *s;
533	const char **vars;
534	int i, n;
535
536	/*
537	 * POSIX requires us to sort the variables.
538	 */
539	n = 0;
540	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
541		for (vp = *vpp; vp; vp = vp->next) {
542			if (!(vp->flags & VUNSET))
543				n++;
544		}
545	}
546
547	INTON;
548	vars = ckmalloc(n * sizeof(*vars));
549	i = 0;
550	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
551		for (vp = *vpp; vp; vp = vp->next) {
552			if (!(vp->flags & VUNSET))
553				vars[i++] = vp->text;
554		}
555	}
556
557	qsort(vars, n, sizeof(*vars), var_compare);
558	for (i = 0; i < n; i++) {
559		for (s = vars[i]; *s != '='; s++)
560			out1c(*s);
561		out1c('=');
562		out1qstr(s + 1);
563		out1c('\n');
564	}
565	ckfree(vars);
566	INTOFF;
567
568	return 0;
569}
570
571
572
573/*
574 * The export and readonly commands.
575 */
576
577int
578exportcmd(int argc, char **argv)
579{
580	struct var **vpp;
581	struct var *vp;
582	char *name;
583	char *p;
584	char *cmdname;
585	int ch, values;
586	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
587
588	cmdname = argv[0];
589	optreset = optind = 1;
590	opterr = 0;
591	values = 0;
592	while ((ch = getopt(argc, argv, "p")) != -1) {
593		switch (ch) {
594		case 'p':
595			values = 1;
596			break;
597		case '?':
598		default:
599			error("unknown option: -%c", optopt);
600		}
601	}
602	argc -= optind;
603	argv += optind;
604
605	if (values && argc != 0)
606		error("-p requires no arguments");
607	listsetvar(cmdenviron);
608	if (argc != 0) {
609		while ((name = *argv++) != NULL) {
610			if ((p = strchr(name, '=')) != NULL) {
611				p++;
612			} else {
613				vpp = hashvar(name);
614				for (vp = *vpp ; vp ; vp = vp->next) {
615					if (varequal(vp->text, name)) {
616
617						vp->flags |= flag;
618						if ((vp->flags & VEXPORT) && localevar(vp->text)) {
619							change_env(vp->text, 1);
620							(void) setlocale(LC_ALL, "");
621						}
622						goto found;
623					}
624				}
625			}
626			setvar(name, p, flag);
627found:;
628		}
629	} else {
630		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
631			for (vp = *vpp ; vp ; vp = vp->next) {
632				if (vp->flags & flag) {
633					if (values) {
634						out1str(cmdname);
635						out1c(' ');
636					}
637					for (p = vp->text ; *p != '=' ; p++)
638						out1c(*p);
639					if (values && !(vp->flags & VUNSET)) {
640						out1c('=');
641						out1qstr(p + 1);
642					}
643					out1c('\n');
644				}
645			}
646		}
647	}
648	return 0;
649}
650
651
652/*
653 * The "local" command.
654 */
655
656int
657localcmd(int argc __unused, char **argv __unused)
658{
659	char *name;
660
661	if (! in_function())
662		error("Not in a function");
663	while ((name = *argptr++) != NULL) {
664		mklocal(name);
665	}
666	return 0;
667}
668
669
670/*
671 * Make a variable a local variable.  When a variable is made local, it's
672 * value and flags are saved in a localvar structure.  The saved values
673 * will be restored when the shell function returns.  We handle the name
674 * "-" as a special case.
675 */
676
677void
678mklocal(char *name)
679{
680	struct localvar *lvp;
681	struct var **vpp;
682	struct var *vp;
683
684	INTOFF;
685	lvp = ckmalloc(sizeof (struct localvar));
686	if (name[0] == '-' && name[1] == '\0') {
687		lvp->text = ckmalloc(sizeof optlist);
688		memcpy(lvp->text, optlist, sizeof optlist);
689		vp = NULL;
690	} else {
691		vpp = hashvar(name);
692		for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next);
693		if (vp == NULL) {
694			if (strchr(name, '='))
695				setvareq(savestr(name), VSTRFIXED);
696			else
697				setvar(name, NULL, VSTRFIXED);
698			vp = *vpp;	/* the new variable */
699			lvp->text = NULL;
700			lvp->flags = VUNSET;
701		} else {
702			lvp->text = vp->text;
703			lvp->flags = vp->flags;
704			vp->flags |= VSTRFIXED|VTEXTFIXED;
705			if (strchr(name, '='))
706				setvareq(savestr(name), 0);
707		}
708	}
709	lvp->vp = vp;
710	lvp->next = localvars;
711	localvars = lvp;
712	INTON;
713}
714
715
716/*
717 * Called after a function returns.
718 */
719
720void
721poplocalvars(void)
722{
723	struct localvar *lvp;
724	struct var *vp;
725
726	while ((lvp = localvars) != NULL) {
727		localvars = lvp->next;
728		vp = lvp->vp;
729		if (vp == NULL) {	/* $- saved */
730			memcpy(optlist, lvp->text, sizeof optlist);
731			ckfree(lvp->text);
732		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
733			(void)unsetvar(vp->text);
734		} else {
735			if ((vp->flags & VTEXTFIXED) == 0)
736				ckfree(vp->text);
737			vp->flags = lvp->flags;
738			vp->text = lvp->text;
739		}
740		ckfree(lvp);
741	}
742}
743
744
745int
746setvarcmd(int argc, char **argv)
747{
748	if (argc <= 2)
749		return unsetcmd(argc, argv);
750	else if (argc == 3)
751		setvar(argv[1], argv[2], 0);
752	else
753		error("List assignment not implemented");
754	return 0;
755}
756
757
758/*
759 * The unset builtin command.  We unset the function before we unset the
760 * variable to allow a function to be unset when there is a readonly variable
761 * with the same name.
762 */
763
764int
765unsetcmd(int argc __unused, char **argv __unused)
766{
767	char **ap;
768	int i;
769	int flg_func = 0;
770	int flg_var = 0;
771	int ret = 0;
772
773	while ((i = nextopt("vf")) != '\0') {
774		if (i == 'f')
775			flg_func = 1;
776		else
777			flg_var = 1;
778	}
779	if (flg_func == 0 && flg_var == 0)
780		flg_var = 1;
781
782	for (ap = argptr; *ap ; ap++) {
783		if (flg_func)
784			ret |= unsetfunc(*ap);
785		if (flg_var)
786			ret |= unsetvar(*ap);
787	}
788	return ret;
789}
790
791
792/*
793 * Unset the specified variable.
794 */
795
796int
797unsetvar(char *s)
798{
799	struct var **vpp;
800	struct var *vp;
801
802	vpp = hashvar(s);
803	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
804		if (varequal(vp->text, s)) {
805			if (vp->flags & VREADONLY)
806				return (1);
807			INTOFF;
808			if (*(strchr(vp->text, '=') + 1) != '\0')
809				setvar(s, nullstr, 0);
810			if ((vp->flags & VEXPORT) && localevar(vp->text)) {
811				change_env(s, 0);
812				setlocale(LC_ALL, "");
813			}
814			vp->flags &= ~VEXPORT;
815			vp->flags |= VUNSET;
816			if ((vp->flags & VSTRFIXED) == 0) {
817				if ((vp->flags & VTEXTFIXED) == 0)
818					ckfree(vp->text);
819				*vpp = vp->next;
820				ckfree(vp);
821			}
822			INTON;
823			return (0);
824		}
825	}
826
827	return (0);
828}
829
830
831
832/*
833 * Find the appropriate entry in the hash table from the name.
834 */
835
836STATIC struct var **
837hashvar(char *p)
838{
839	unsigned int hashval;
840
841	hashval = ((unsigned char) *p) << 4;
842	while (*p && *p != '=')
843		hashval += (unsigned char) *p++;
844	return &vartab[hashval % VTABSIZE];
845}
846
847
848
849/*
850 * Returns true if the two strings specify the same varable.  The first
851 * variable name is terminated by '='; the second may be terminated by
852 * either '=' or '\0'.
853 */
854
855STATIC int
856varequal(char *p, char *q)
857{
858	while (*p == *q++) {
859		if (*p++ == '=')
860			return 1;
861	}
862	if (*p == '=' && *(q - 1) == '\0')
863		return 1;
864	return 0;
865}
866