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 199660 2009-11-22 18:23:30Z 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 listsetvar(cmdenviron);
611 if (argc != 0) {
612 while ((name = *argv++) != NULL) {
613 if ((p = strchr(name, '=')) != NULL) {
614 p++;
615 } else {
616 vpp = hashvar(name);
617 for (vp = *vpp ; vp ; vp = vp->next) {
618 if (varequal(vp->text, name)) {
619
620 vp->flags |= flag;
621 if ((vp->flags & VEXPORT) && localevar(vp->text)) {
622 change_env(vp->text, 1);
623 (void) setlocale(LC_ALL, "");
624 }
625 goto found;
626 }
627 }
628 }
629 setvar(name, p, flag);
630found:;
631 }
632 } else {
633 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
634 for (vp = *vpp ; vp ; vp = vp->next) {
635 if (vp->flags & flag) {
636 if (values) {
637 out1str(cmdname);
638 out1c(' ');
639 }
640 for (p = vp->text ; *p != '=' ; p++)
641 out1c(*p);
642 if (values && !(vp->flags & VUNSET)) {
643 out1c('=');
644 out1qstr(p + 1);
645 }
646 out1c('\n');
647 }
648 }
649 }
650 }
651 return 0;
652}
653
654
655/*
656 * The "local" command.
657 */
658
659int
660localcmd(int argc __unused, char **argv __unused)
661{
662 char *name;
663
664 if (! in_function())
665 error("Not in a function");
666 while ((name = *argptr++) != NULL) {
667 mklocal(name);
668 }
669 return 0;
670}
671
672
673/*
674 * Make a variable a local variable. When a variable is made local, it's
675 * value and flags are saved in a localvar structure. The saved values
676 * will be restored when the shell function returns. We handle the name
677 * "-" as a special case.
678 */
679
680void
681mklocal(char *name)
682{
683 struct localvar *lvp;
684 struct var **vpp;
685 struct var *vp;
686
687 INTOFF;
688 lvp = ckmalloc(sizeof (struct localvar));
689 if (name[0] == '-' && name[1] == '\0') {
690 lvp->text = ckmalloc(sizeof optlist);
691 memcpy(lvp->text, optlist, sizeof optlist);
692 vp = NULL;
693 } else {
694 vpp = hashvar(name);
695 for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next);
696 if (vp == NULL) {
697 if (strchr(name, '='))
698 setvareq(savestr(name), VSTRFIXED);
699 else
700 setvar(name, NULL, VSTRFIXED);
701 vp = *vpp; /* the new variable */
702 lvp->text = NULL;
703 lvp->flags = VUNSET;
704 } else {
705 lvp->text = vp->text;
706 lvp->flags = vp->flags;
707 vp->flags |= VSTRFIXED|VTEXTFIXED;
708 if (strchr(name, '='))
709 setvareq(savestr(name), 0);
710 }
711 }
712 lvp->vp = vp;
713 lvp->next = localvars;
714 localvars = lvp;
715 INTON;
716}
717
718
719/*
720 * Called after a function returns.
721 */
722
723void
724poplocalvars(void)
725{
726 struct localvar *lvp;
727 struct var *vp;
728
729 while ((lvp = localvars) != NULL) {
730 localvars = lvp->next;
731 vp = lvp->vp;
732 if (vp == NULL) { /* $- saved */
733 memcpy(optlist, lvp->text, sizeof optlist);
734 ckfree(lvp->text);
735 } else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
736 (void)unsetvar(vp->text);
737 } else {
738 if ((vp->flags & VTEXTFIXED) == 0)
739 ckfree(vp->text);
740 vp->flags = lvp->flags;
741 vp->text = lvp->text;
742 }
743 ckfree(lvp);
744 }
745}
746
747
748int
749setvarcmd(int argc, char **argv)
750{
751 if (argc <= 2)
752 return unsetcmd(argc, argv);
753 else if (argc == 3)
754 setvar(argv[1], argv[2], 0);
755 else
756 error("List assignment not implemented");
757 return 0;
758}
759
760
761/*
762 * The unset builtin command. We unset the function before we unset the
763 * variable to allow a function to be unset when there is a readonly variable
764 * with the same name.
765 */
766
767int
768unsetcmd(int argc __unused, char **argv __unused)
769{
770 char **ap;
771 int i;
772 int flg_func = 0;
773 int flg_var = 0;
774 int ret = 0;
775
776 while ((i = nextopt("vf")) != '\0') {
777 if (i == 'f')
778 flg_func = 1;
779 else
780 flg_var = 1;
781 }
782 if (flg_func == 0 && flg_var == 0)
783 flg_var = 1;
784
785 for (ap = argptr; *ap ; ap++) {
786 if (flg_func)
787 ret |= unsetfunc(*ap);
788 if (flg_var)
789 ret |= unsetvar(*ap);
790 }
791 return ret;
792}
793
794
795/*
796 * Unset the specified variable.
797 */
798
799int
800unsetvar(char *s)
801{
802 struct var **vpp;
803 struct var *vp;
804
805 vpp = hashvar(s);
806 for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
807 if (varequal(vp->text, s)) {
808 if (vp->flags & VREADONLY)
809 return (1);
810 INTOFF;
811 if (*(strchr(vp->text, '=') + 1) != '\0')
812 setvar(s, nullstr, 0);
813 if ((vp->flags & VEXPORT) && localevar(vp->text)) {
814 change_env(s, 0);
815 setlocale(LC_ALL, "");
816 }
817 vp->flags &= ~VEXPORT;
818 vp->flags |= VUNSET;
819 if ((vp->flags & VSTRFIXED) == 0) {
820 if ((vp->flags & VTEXTFIXED) == 0)
821 ckfree(vp->text);
822 *vpp = vp->next;
823 ckfree(vp);
824 }
825 INTON;
826 return (0);
827 }
828 }
829
830 return (0);
831}
832
833
834
835/*
836 * Find the appropriate entry in the hash table from the name.
837 */
838
839STATIC struct var **
840hashvar(char *p)
841{
842 unsigned int hashval;
843
844 hashval = ((unsigned char) *p) << 4;
845 while (*p && *p != '=')
846 hashval += (unsigned char) *p++;
847 return &vartab[hashval % VTABSIZE];
848}
849
850
851
852/*
853 * Returns true if the two strings specify the same varable. The first
854 * variable name is terminated by '='; the second may be terminated by
855 * either '=' or '\0'.
856 */
857
858STATIC int
859varequal(char *p, char *q)
860{
861 while (*p == *q++) {
862 if (*p++ == '=')
863 return 1;
864 }
865 if (*p == '=' && *(q - 1) == '\0')
866 return 1;
867 return 0;
868}