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}