xref: /freebsd/bin/sh/var.c (revision 380a989b3223d455375b4fae70fd0b9bdd43bafb) 
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
39 static char sccsid[] = "@(#)var.c	8.3 (Berkeley) 5/4/95";
40 #endif
41 static const char rcsid[] =
42 	"$Id$";
43 #endif /* not lint */
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 
76 struct varinit {
77 	struct var *var;
78 	int flags;
79 	char *text;
80 	void (*func) __P((const char *));
81 };
82 
83 
84 #if ATTY
85 struct var vatty;
86 #endif
87 #ifndef NO_HISTORY
88 struct var vhistsize;
89 #endif
90 struct var vifs;
91 struct var vmail;
92 struct var vmpath;
93 struct var vpath;
94 struct var vps1;
95 struct var vps2;
96 struct var vvers;
97 #if ATTY
98 struct var vterm;
99 #endif
100 struct var voptind;
101 
102 const struct varinit varinit[] = {
103 #if ATTY
104 	{ &vatty,	VSTRFIXED|VTEXTFIXED|VUNSET,	"ATTY=",
105 	  NULL },
106 #endif
107 #ifndef NO_HISTORY
108 	{ &vhistsize,	VSTRFIXED|VTEXTFIXED|VUNSET,	"HISTSIZE=",
109 	  sethistsize },
110 #endif
111 	{ &vifs,	VSTRFIXED|VTEXTFIXED,		"IFS= \t\n",
112 	  NULL },
113 	{ &vmail,	VSTRFIXED|VTEXTFIXED|VUNSET,	"MAIL=",
114 	  NULL },
115 	{ &vmpath,	VSTRFIXED|VTEXTFIXED|VUNSET,	"MAILPATH=",
116 	  NULL },
117 	{ &vpath,	VSTRFIXED|VTEXTFIXED,		"PATH=/bin:/usr/bin",
118 	  changepath },
119 	/*
120 	 * vps1 depends on uid
121 	 */
122 	{ &vps2,	VSTRFIXED|VTEXTFIXED,		"PS2=> ",
123 	  NULL },
124 #if ATTY
125 	{ &vterm,	VSTRFIXED|VTEXTFIXED|VUNSET,	"TERM=",
126 	  NULL },
127 #endif
128 	{ &voptind,	VSTRFIXED|VTEXTFIXED,		"OPTIND=1",
129 	  getoptsreset },
130 	{ NULL,	0,				NULL,
131 	  NULL }
132 };
133 
134 struct var *vartab[VTABSIZE];
135 
136 STATIC struct var **hashvar __P((char *));
137 STATIC int varequal __P((char *, char *));
138 STATIC int localevar __P((char *));
139 
140 /*
141  * Initialize the varable symbol tables and import the environment
142  */
143 
144 #ifdef mkinit
145 INCLUDE "var.h"
146 INIT {
147 	char **envp;
148 	extern char **environ;
149 
150 	initvar();
151 	for (envp = environ ; *envp ; envp++) {
152 		if (strchr(*envp, '=')) {
153 			setvareq(*envp, VEXPORT|VTEXTFIXED);
154 		}
155 	}
156 }
157 #endif
158 
159 
160 /*
161  * This routine initializes the builtin variables.  It is called when the
162  * shell is initialized and again when a shell procedure is spawned.
163  */
164 
165 void
166 initvar() {
167 	const struct varinit *ip;
168 	struct var *vp;
169 	struct var **vpp;
170 
171 	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
172 		if ((vp->flags & VEXPORT) == 0) {
173 			vpp = hashvar(ip->text);
174 			vp->next = *vpp;
175 			*vpp = vp;
176 			vp->text = ip->text;
177 			vp->flags = ip->flags;
178 			vp->func = ip->func;
179 		}
180 	}
181 	/*
182 	 * PS1 depends on uid
183 	 */
184 	if ((vps1.flags & VEXPORT) == 0) {
185 		vpp = hashvar("PS1=");
186 		vps1.next = *vpp;
187 		*vpp = &vps1;
188 		vps1.text = geteuid() ? "PS1=$ " : "PS1=# ";
189 		vps1.flags = VSTRFIXED|VTEXTFIXED;
190 	}
191 }
192 
193 /*
194  * Safe version of setvar, returns 1 on success 0 on failure.
195  */
196 
197 int
198 setvarsafe(name, val, flags)
199 	char *name, *val;
200 	int flags;
201 {
202 	struct jmploc jmploc;
203 	struct jmploc *volatile savehandler = handler;
204 	int err = 0;
205 #if __GNUC__
206 	/* Avoid longjmp clobbering */
207 	(void) &err;
208 #endif
209 
210 	if (setjmp(jmploc.loc))
211 		err = 1;
212 	else {
213 		handler = &jmploc;
214 		setvar(name, val, flags);
215 	}
216 	handler = savehandler;
217 	return err;
218 }
219 
220 /*
221  * Set the value of a variable.  The flags argument is ored with the
222  * flags of the variable.  If val is NULL, the variable is unset.
223  */
224 
225 void
226 setvar(name, val, flags)
227 	char *name, *val;
228 	int flags;
229 {
230 	char *p, *q;
231 	int len;
232 	int namelen;
233 	char *nameeq;
234 	int isbad;
235 
236 	isbad = 0;
237 	p = name;
238 	if (! is_name(*p))
239 		isbad = 1;
240 	p++;
241 	for (;;) {
242 		if (! is_in_name(*p)) {
243 			if (*p == '\0' || *p == '=')
244 				break;
245 			isbad = 1;
246 		}
247 		p++;
248 	}
249 	namelen = p - name;
250 	if (isbad)
251 		error("%.*s: bad variable name", namelen, name);
252 	len = namelen + 2;		/* 2 is space for '=' and '\0' */
253 	if (val == NULL) {
254 		flags |= VUNSET;
255 	} else {
256 		len += strlen(val);
257 	}
258 	p = nameeq = ckmalloc(len);
259 	q = name;
260 	while (--namelen >= 0)
261 		*p++ = *q++;
262 	*p++ = '=';
263 	*p = '\0';
264 	if (val)
265 		scopy(val, p);
266 	setvareq(nameeq, flags);
267 }
268 
269 STATIC int
270 localevar(s)
271 	char *s;
272 	{
273 	static char *lnames[7] = {
274 		"ALL", "COLLATE", "CTYPE", "MONETARY",
275 		"NUMERIC", "TIME", NULL
276 	};
277 	char **ss;
278 
279 	if (*s != 'L')
280 		return 0;
281 	if (varequal(s + 1, "ANG"))
282 		return 1;
283 	if (strncmp(s + 1, "C_", 2) != 0)
284 		return 0;
285 	for (ss = lnames; *ss ; ss++)
286 		if (varequal(s + 3, *ss))
287 			return 1;
288 	return 0;
289 }
290 
291 /*
292  * Same as setvar except that the variable and value are passed in
293  * the first argument as name=value.  Since the first argument will
294  * be actually stored in the table, it should not be a string that
295  * will go away.
296  */
297 
298 void
299 setvareq(s, flags)
300 	char *s;
301 	int flags;
302 {
303 	struct var *vp, **vpp;
304 
305 	vpp = hashvar(s);
306 	for (vp = *vpp ; vp ; vp = vp->next) {
307 		if (varequal(s, vp->text)) {
308 			if (vp->flags & VREADONLY) {
309 				size_t len = strchr(s, '=') - s;
310 				error("%.*s: is read only", len, s);
311 			}
312 			INTOFF;
313 
314 			if (vp->func && (flags & VNOFUNC) == 0)
315 				(*vp->func)(strchr(s, '=') + 1);
316 
317 			if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
318 				ckfree(vp->text);
319 
320 			vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
321 			vp->flags |= flags;
322 			vp->text = s;
323 
324 			/*
325 			 * We could roll this to a function, to handle it as
326 			 * a regular variable function callback, but why bother?
327 			 */
328 			if (vp == &vmpath || (vp == &vmail && ! mpathset()))
329 				chkmail(1);
330 			if ((vp->flags & VEXPORT) && localevar(s)) {
331 				putenv(s);
332 				(void) setlocale(LC_ALL, "");
333 			}
334 			INTON;
335 			return;
336 		}
337 	}
338 	/* not found */
339 	vp = ckmalloc(sizeof (*vp));
340 	vp->flags = flags;
341 	vp->text = s;
342 	vp->next = *vpp;
343 	vp->func = NULL;
344 	INTOFF;
345 	*vpp = vp;
346 	if ((vp->flags & VEXPORT) && localevar(s)) {
347 		putenv(s);
348 		(void) setlocale(LC_ALL, "");
349 	}
350 	INTON;
351 }
352 
353 
354 
355 /*
356  * Process a linked list of variable assignments.
357  */
358 
359 void
360 listsetvar(list)
361 	struct strlist *list;
362 	{
363 	struct strlist *lp;
364 
365 	INTOFF;
366 	for (lp = list ; lp ; lp = lp->next) {
367 		setvareq(savestr(lp->text), 0);
368 	}
369 	INTON;
370 }
371 
372 
373 
374 /*
375  * Find the value of a variable.  Returns NULL if not set.
376  */
377 
378 char *
379 lookupvar(name)
380 	char *name;
381 	{
382 	struct var *v;
383 
384 	for (v = *hashvar(name) ; v ; v = v->next) {
385 		if (varequal(v->text, name)) {
386 			if (v->flags & VUNSET)
387 				return NULL;
388 			return strchr(v->text, '=') + 1;
389 		}
390 	}
391 	return NULL;
392 }
393 
394 
395 
396 /*
397  * Search the environment of a builtin command.  If the second argument
398  * is nonzero, return the value of a variable even if it hasn't been
399  * exported.
400  */
401 
402 char *
403 bltinlookup(name, doall)
404 	char *name;
405 	int doall;
406 {
407 	struct strlist *sp;
408 	struct var *v;
409 
410 	for (sp = cmdenviron ; sp ; sp = sp->next) {
411 		if (varequal(sp->text, name))
412 			return strchr(sp->text, '=') + 1;
413 	}
414 	for (v = *hashvar(name) ; v ; v = v->next) {
415 		if (varequal(v->text, name)) {
416 			if ((v->flags & VUNSET)
417 			 || (!doall && (v->flags & VEXPORT) == 0))
418 				return NULL;
419 			return strchr(v->text, '=') + 1;
420 		}
421 	}
422 	return NULL;
423 }
424 
425 
426 
427 /*
428  * Generate a list of exported variables.  This routine is used to construct
429  * the third argument to execve when executing a program.
430  */
431 
432 char **
433 environment() {
434 	int nenv;
435 	struct var **vpp;
436 	struct var *vp;
437 	char **env, **ep;
438 
439 	nenv = 0;
440 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
441 		for (vp = *vpp ; vp ; vp = vp->next)
442 			if (vp->flags & VEXPORT)
443 				nenv++;
444 	}
445 	ep = env = stalloc((nenv + 1) * sizeof *env);
446 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
447 		for (vp = *vpp ; vp ; vp = vp->next)
448 			if (vp->flags & VEXPORT)
449 				*ep++ = vp->text;
450 	}
451 	*ep = NULL;
452 	return env;
453 }
454 
455 
456 /*
457  * Called when a shell procedure is invoked to clear out nonexported
458  * variables.  It is also necessary to reallocate variables of with
459  * VSTACK set since these are currently allocated on the stack.
460  */
461 
462 #ifdef mkinit
463 MKINIT void shprocvar();
464 
465 SHELLPROC {
466 	shprocvar();
467 }
468 #endif
469 
470 void
471 shprocvar() {
472 	struct var **vpp;
473 	struct var *vp, **prev;
474 
475 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
476 		for (prev = vpp ; (vp = *prev) != NULL ; ) {
477 			if ((vp->flags & VEXPORT) == 0) {
478 				*prev = vp->next;
479 				if ((vp->flags & VTEXTFIXED) == 0)
480 					ckfree(vp->text);
481 				if ((vp->flags & VSTRFIXED) == 0)
482 					ckfree(vp);
483 			} else {
484 				if (vp->flags & VSTACK) {
485 					vp->text = savestr(vp->text);
486 					vp->flags &=~ VSTACK;
487 				}
488 				prev = &vp->next;
489 			}
490 		}
491 	}
492 	initvar();
493 }
494 
495 
496 
497 /*
498  * Command to list all variables which are set.  Currently this command
499  * is invoked from the set command when the set command is called without
500  * any variables.
501  */
502 
503 int
504 showvarscmd(argc, argv)
505 	int argc __unused;
506 	char **argv __unused;
507 {
508 	struct var **vpp;
509 	struct var *vp;
510 
511 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
512 		for (vp = *vpp ; vp ; vp = vp->next) {
513 			if ((vp->flags & VUNSET) == 0)
514 				out1fmt("%s\n", vp->text);
515 		}
516 	}
517 	return 0;
518 }
519 
520 
521 
522 /*
523  * The export and readonly commands.
524  */
525 
526 int
527 exportcmd(argc, argv)
528 	int argc;
529 	char **argv;
530 {
531 	struct var **vpp;
532 	struct var *vp;
533 	char *name;
534 	char *p;
535 	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
536 
537 	listsetvar(cmdenviron);
538 	if (argc > 1) {
539 		while ((name = *argptr++) != NULL) {
540 			if ((p = strchr(name, '=')) != NULL) {
541 				p++;
542 			} else {
543 				vpp = hashvar(name);
544 				for (vp = *vpp ; vp ; vp = vp->next) {
545 					if (varequal(vp->text, name)) {
546 						vp->flags |= flag;
547 						if ((vp->flags & VEXPORT) && localevar(vp->text)) {
548 							putenv(vp->text);
549 							(void) setlocale(LC_ALL, "");
550 						}
551 						goto found;
552 					}
553 				}
554 			}
555 			setvar(name, p, flag);
556 found:;
557 		}
558 	} else {
559 		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
560 			for (vp = *vpp ; vp ; vp = vp->next) {
561 				if (vp->flags & flag) {
562 					for (p = vp->text ; *p != '=' ; p++)
563 						out1c(*p);
564 					out1c('\n');
565 				}
566 			}
567 		}
568 	}
569 	return 0;
570 }
571 
572 
573 /*
574  * The "local" command.
575  */
576 
577 int
578 localcmd(argc, argv)
579 	int argc __unused;
580 	char **argv __unused;
581 {
582 	char *name;
583 
584 	if (! in_function())
585 		error("Not in a function");
586 	while ((name = *argptr++) != NULL) {
587 		mklocal(name);
588 	}
589 	return 0;
590 }
591 
592 
593 /*
594  * Make a variable a local variable.  When a variable is made local, it's
595  * value and flags are saved in a localvar structure.  The saved values
596  * will be restored when the shell function returns.  We handle the name
597  * "-" as a special case.
598  */
599 
600 void
601 mklocal(name)
602 	char *name;
603 	{
604 	struct localvar *lvp;
605 	struct var **vpp;
606 	struct var *vp;
607 
608 	INTOFF;
609 	lvp = ckmalloc(sizeof (struct localvar));
610 	if (name[0] == '-' && name[1] == '\0') {
611 		lvp->text = ckmalloc(sizeof optlist);
612 		memcpy(lvp->text, optlist, sizeof optlist);
613 		vp = NULL;
614 	} else {
615 		vpp = hashvar(name);
616 		for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next);
617 		if (vp == NULL) {
618 			if (strchr(name, '='))
619 				setvareq(savestr(name), VSTRFIXED);
620 			else
621 				setvar(name, NULL, VSTRFIXED);
622 			vp = *vpp;	/* the new variable */
623 			lvp->text = NULL;
624 			lvp->flags = VUNSET;
625 		} else {
626 			lvp->text = vp->text;
627 			lvp->flags = vp->flags;
628 			vp->flags |= VSTRFIXED|VTEXTFIXED;
629 			if (strchr(name, '='))
630 				setvareq(savestr(name), 0);
631 		}
632 	}
633 	lvp->vp = vp;
634 	lvp->next = localvars;
635 	localvars = lvp;
636 	INTON;
637 }
638 
639 
640 /*
641  * Called after a function returns.
642  */
643 
644 void
645 poplocalvars() {
646 	struct localvar *lvp;
647 	struct var *vp;
648 
649 	while ((lvp = localvars) != NULL) {
650 		localvars = lvp->next;
651 		vp = lvp->vp;
652 		if (vp == NULL) {	/* $- saved */
653 			memcpy(optlist, lvp->text, sizeof optlist);
654 			ckfree(lvp->text);
655 		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
656 			(void)unsetvar(vp->text);
657 		} else {
658 			if ((vp->flags & VTEXTFIXED) == 0)
659 				ckfree(vp->text);
660 			vp->flags = lvp->flags;
661 			vp->text = lvp->text;
662 		}
663 		ckfree(lvp);
664 	}
665 }
666 
667 
668 int
669 setvarcmd(argc, argv)
670 	int argc;
671 	char **argv;
672 {
673 	if (argc <= 2)
674 		return unsetcmd(argc, argv);
675 	else if (argc == 3)
676 		setvar(argv[1], argv[2], 0);
677 	else
678 		error("List assignment not implemented");
679 	return 0;
680 }
681 
682 
683 /*
684  * The unset builtin command.  We unset the function before we unset the
685  * variable to allow a function to be unset when there is a readonly variable
686  * with the same name.
687  */
688 
689 int
690 unsetcmd(argc, argv)
691 	int argc __unused;
692 	char **argv __unused;
693 {
694 	char **ap;
695 	int i;
696 	int flg_func = 0;
697 	int flg_var = 0;
698 	int ret = 0;
699 
700 	while ((i = nextopt("vf")) != '\0') {
701 		if (i == 'f')
702 			flg_func = 1;
703 		else
704 			flg_var = 1;
705 	}
706 	if (flg_func == 0 && flg_var == 0)
707 		flg_var = 1;
708 
709 	for (ap = argptr; *ap ; ap++) {
710 		if (flg_func)
711 			ret |= unsetfunc(*ap);
712 		if (flg_var)
713 			ret |= unsetvar(*ap);
714 	}
715 	return ret;
716 }
717 
718 
719 /*
720  * Unset the specified variable.
721  */
722 
723 int
724 unsetvar(s)
725 	char *s;
726 	{
727 	struct var **vpp;
728 	struct var *vp;
729 
730 	vpp = hashvar(s);
731 	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
732 		if (varequal(vp->text, s)) {
733 			if (vp->flags & VREADONLY)
734 				return (1);
735 			INTOFF;
736 			if (*(strchr(vp->text, '=') + 1) != '\0')
737 				setvar(s, nullstr, 0);
738 			if ((vp->flags & VEXPORT) && localevar(vp->text)) {
739 				unsetenv(s);
740 				setlocale(LC_ALL, "");
741 			}
742 			vp->flags &= ~VEXPORT;
743 			vp->flags |= VUNSET;
744 			if ((vp->flags & VSTRFIXED) == 0) {
745 				if ((vp->flags & VTEXTFIXED) == 0)
746 					ckfree(vp->text);
747 				*vpp = vp->next;
748 				ckfree(vp);
749 			}
750 			INTON;
751 			return (0);
752 		}
753 	}
754 
755 	return (1);
756 }
757 
758 
759 
760 /*
761  * Find the appropriate entry in the hash table from the name.
762  */
763 
764 STATIC struct var **
765 hashvar(p)
766 	char *p;
767 	{
768 	unsigned int hashval;
769 
770 	hashval = ((unsigned char) *p) << 4;
771 	while (*p && *p != '=')
772 		hashval += (unsigned char) *p++;
773 	return &vartab[hashval % VTABSIZE];
774 }
775 
776 
777 
778 /*
779  * Returns true if the two strings specify the same varable.  The first
780  * variable name is terminated by '='; the second may be terminated by
781  * either '=' or '\0'.
782  */
783 
784 STATIC int
785 varequal(p, q)
786 	char *p, *q;
787 	{
788 	while (*p == *q++) {
789 		if (*p++ == '=')
790 			return 1;
791 	}
792 	if (*p == '=' && *(q - 1) == '\0')
793 		return 1;
794 	return 0;
795 }
796