Home | History | Annotate | Line # | Download | only in sh
var.c revision 1.17 
      1 /*	$NetBSD: var.c,v 1.17 1997/03/14 01:42:24 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1991, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * Kenneth Almquist.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *	This product includes software developed by the University of
     21  *	California, Berkeley and its contributors.
     22  * 4. Neither the name of the University nor the names of its contributors
     23  *    may be used to endorse or promote products derived from this software
     24  *    without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     36  * SUCH DAMAGE.
     37  */
     38 
     39 #ifndef lint
     40 #if 0
     41 static char sccsid[] = "@(#)var.c	8.3 (Berkeley) 5/4/95";
     42 #else
     43 static char rcsid[] = "$NetBSD: var.c,v 1.17 1997/03/14 01:42:24 christos Exp $";
     44 #endif
     45 #endif /* not lint */
     46 
     47 #include <unistd.h>
     48 #include <stdlib.h>
     49 
     50 /*
     51  * Shell variables.
     52  */
     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 SMALL
     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 SMALL
     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 SMALL
    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 
    139 /*
    140  * Initialize the varable symbol tables and import the environment
    141  */
    142 
    143 #ifdef mkinit
    144 INCLUDE "var.h"
    145 INIT {
    146 	char **envp;
    147 	extern char **environ;
    148 
    149 	initvar();
    150 	for (envp = environ ; *envp ; envp++) {
    151 		if (strchr(*envp, '=')) {
    152 			setvareq(*envp, VEXPORT|VTEXTFIXED);
    153 		}
    154 	}
    155 }
    156 #endif
    157 
    158 
    159 /*
    160  * This routine initializes the builtin variables.  It is called when the
    161  * shell is initialized and again when a shell procedure is spawned.
    162  */
    163 
    164 void
    165 initvar() {
    166 	const struct varinit *ip;
    167 	struct var *vp;
    168 	struct var **vpp;
    169 
    170 	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
    171 		if ((vp->flags & VEXPORT) == 0) {
    172 			vpp = hashvar(ip->text);
    173 			vp->next = *vpp;
    174 			*vpp = vp;
    175 			vp->text = ip->text;
    176 			vp->flags = ip->flags;
    177 			vp->func = ip->func;
    178 		}
    179 	}
    180 	/*
    181 	 * PS1 depends on uid
    182 	 */
    183 	if ((vps1.flags & VEXPORT) == 0) {
    184 		vpp = hashvar("PS1=");
    185 		vps1.next = *vpp;
    186 		*vpp = &vps1;
    187 		vps1.text = geteuid() ? "PS1=$ " : "PS1=# ";
    188 		vps1.flags = VSTRFIXED|VTEXTFIXED;
    189 	}
    190 }
    191 
    192 /*
    193  * Safe version of setvar, returns 1 on success 0 on failure.
    194  */
    195 
    196 int
    197 setvarsafe(name, val, flags)
    198 	char *name, *val;
    199 	int flags;
    200 {
    201 	struct jmploc jmploc;
    202 	struct jmploc *volatile savehandler = handler;
    203 	int err = 0;
    204 
    205 	if (setjmp(jmploc.loc))
    206 		err = 1;
    207 	else {
    208 		handler = &jmploc;
    209 		setvar(name, val, flags);
    210 	}
    211 	handler = savehandler;
    212 	return err;
    213 }
    214 
    215 /*
    216  * Set the value of a variable.  The flags argument is ored with the
    217  * flags of the variable.  If val is NULL, the variable is unset.
    218  */
    219 
    220 void
    221 setvar(name, val, flags)
    222 	char *name, *val;
    223 	int flags;
    224 {
    225 	char *p, *q;
    226 	int len;
    227 	int namelen;
    228 	char *nameeq;
    229 	int isbad;
    230 
    231 	isbad = 0;
    232 	p = name;
    233 	if (! is_name(*p))
    234 		isbad = 1;
    235 	p++;
    236 	for (;;) {
    237 		if (! is_in_name(*p)) {
    238 			if (*p == '\0' || *p == '=')
    239 				break;
    240 			isbad = 1;
    241 		}
    242 		p++;
    243 	}
    244 	namelen = p - name;
    245 	if (isbad)
    246 		error("%.*s: bad variable name", namelen, name);
    247 	len = namelen + 2;		/* 2 is space for '=' and '\0' */
    248 	if (val == NULL) {
    249 		flags |= VUNSET;
    250 	} else {
    251 		len += strlen(val);
    252 	}
    253 	p = nameeq = ckmalloc(len);
    254 	q = name;
    255 	while (--namelen >= 0)
    256 		*p++ = *q++;
    257 	*p++ = '=';
    258 	*p = '\0';
    259 	if (val)
    260 		scopy(val, p);
    261 	setvareq(nameeq, flags);
    262 }
    263 
    264 
    265 
    266 /*
    267  * Same as setvar except that the variable and value are passed in
    268  * the first argument as name=value.  Since the first argument will
    269  * be actually stored in the table, it should not be a string that
    270  * will go away.
    271  */
    272 
    273 void
    274 setvareq(s, flags)
    275 	char *s;
    276 	int flags;
    277 {
    278 	struct var *vp, **vpp;
    279 
    280 	vpp = hashvar(s);
    281 	for (vp = *vpp ; vp ; vp = vp->next) {
    282 		if (varequal(s, vp->text)) {
    283 			if (vp->flags & VREADONLY) {
    284 				size_t len = strchr(s, '=') - s;
    285 				error("%.*s: is read only", len, s);
    286 			}
    287 			INTOFF;
    288 
    289 			if (vp->func && (flags & VNOFUNC) == 0)
    290 				(*vp->func)(strchr(s, '=') + 1);
    291 
    292 			if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
    293 				ckfree(vp->text);
    294 
    295 			vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
    296 			vp->flags |= flags;
    297 			vp->text = s;
    298 
    299 			/*
    300 			 * We could roll this to a function, to handle it as
    301 			 * a regular variable function callback, but why bother?
    302 			 */
    303 			if (vp == &vmpath || (vp == &vmail && ! mpathset()))
    304 				chkmail(1);
    305 			INTON;
    306 			return;
    307 		}
    308 	}
    309 	/* not found */
    310 	vp = ckmalloc(sizeof (*vp));
    311 	vp->flags = flags;
    312 	vp->text = s;
    313 	vp->next = *vpp;
    314 	vp->func = NULL;
    315 	*vpp = vp;
    316 }
    317 
    318 
    319 
    320 /*
    321  * Process a linked list of variable assignments.
    322  */
    323 
    324 void
    325 listsetvar(list)
    326 	struct strlist *list;
    327 	{
    328 	struct strlist *lp;
    329 
    330 	INTOFF;
    331 	for (lp = list ; lp ; lp = lp->next) {
    332 		setvareq(savestr(lp->text), 0);
    333 	}
    334 	INTON;
    335 }
    336 
    337 
    338 
    339 /*
    340  * Find the value of a variable.  Returns NULL if not set.
    341  */
    342 
    343 char *
    344 lookupvar(name)
    345 	char *name;
    346 	{
    347 	struct var *v;
    348 
    349 	for (v = *hashvar(name) ; v ; v = v->next) {
    350 		if (varequal(v->text, name)) {
    351 			if (v->flags & VUNSET)
    352 				return NULL;
    353 			return strchr(v->text, '=') + 1;
    354 		}
    355 	}
    356 	return NULL;
    357 }
    358 
    359 
    360 
    361 /*
    362  * Search the environment of a builtin command.  If the second argument
    363  * is nonzero, return the value of a variable even if it hasn't been
    364  * exported.
    365  */
    366 
    367 char *
    368 bltinlookup(name, doall)
    369 	char *name;
    370 	int doall;
    371 {
    372 	struct strlist *sp;
    373 	struct var *v;
    374 
    375 	for (sp = cmdenviron ; sp ; sp = sp->next) {
    376 		if (varequal(sp->text, name))
    377 			return strchr(sp->text, '=') + 1;
    378 	}
    379 	for (v = *hashvar(name) ; v ; v = v->next) {
    380 		if (varequal(v->text, name)) {
    381 			if ((v->flags & VUNSET)
    382 			 || (!doall && (v->flags & VEXPORT) == 0))
    383 				return NULL;
    384 			return strchr(v->text, '=') + 1;
    385 		}
    386 	}
    387 	return NULL;
    388 }
    389 
    390 
    391 
    392 /*
    393  * Generate a list of exported variables.  This routine is used to construct
    394  * the third argument to execve when executing a program.
    395  */
    396 
    397 char **
    398 environment() {
    399 	int nenv;
    400 	struct var **vpp;
    401 	struct var *vp;
    402 	char **env, **ep;
    403 
    404 	nenv = 0;
    405 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
    406 		for (vp = *vpp ; vp ; vp = vp->next)
    407 			if (vp->flags & VEXPORT)
    408 				nenv++;
    409 	}
    410 	ep = env = stalloc((nenv + 1) * sizeof *env);
    411 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
    412 		for (vp = *vpp ; vp ; vp = vp->next)
    413 			if (vp->flags & VEXPORT)
    414 				*ep++ = vp->text;
    415 	}
    416 	*ep = NULL;
    417 	return env;
    418 }
    419 
    420 
    421 /*
    422  * Called when a shell procedure is invoked to clear out nonexported
    423  * variables.  It is also necessary to reallocate variables of with
    424  * VSTACK set since these are currently allocated on the stack.
    425  */
    426 
    427 #ifdef mkinit
    428 MKINIT void shprocvar();
    429 
    430 SHELLPROC {
    431 	shprocvar();
    432 }
    433 #endif
    434 
    435 void
    436 shprocvar() {
    437 	struct var **vpp;
    438 	struct var *vp, **prev;
    439 
    440 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
    441 		for (prev = vpp ; (vp = *prev) != NULL ; ) {
    442 			if ((vp->flags & VEXPORT) == 0) {
    443 				*prev = vp->next;
    444 				if ((vp->flags & VTEXTFIXED) == 0)
    445 					ckfree(vp->text);
    446 				if ((vp->flags & VSTRFIXED) == 0)
    447 					ckfree(vp);
    448 			} else {
    449 				if (vp->flags & VSTACK) {
    450 					vp->text = savestr(vp->text);
    451 					vp->flags &=~ VSTACK;
    452 				}
    453 				prev = &vp->next;
    454 			}
    455 		}
    456 	}
    457 	initvar();
    458 }
    459 
    460 
    461 
    462 /*
    463  * Command to list all variables which are set.  Currently this command
    464  * is invoked from the set command when the set command is called without
    465  * any variables.
    466  */
    467 
    468 int
    469 showvarscmd(argc, argv)
    470 	int argc;
    471 	char **argv;
    472 {
    473 	struct var **vpp;
    474 	struct var *vp;
    475 
    476 	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
    477 		for (vp = *vpp ; vp ; vp = vp->next) {
    478 			if ((vp->flags & VUNSET) == 0)
    479 				out1fmt("%s\n", vp->text);
    480 		}
    481 	}
    482 	return 0;
    483 }
    484 
    485 
    486 
    487 /*
    488  * The export and readonly commands.
    489  */
    490 
    491 int
    492 exportcmd(argc, argv)
    493 	int argc;
    494 	char **argv;
    495 {
    496 	struct var **vpp;
    497 	struct var *vp;
    498 	char *name;
    499 	char *p;
    500 	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
    501 
    502 	listsetvar(cmdenviron);
    503 	if (argc > 1) {
    504 		while ((name = *argptr++) != NULL) {
    505 			if ((p = strchr(name, '=')) != NULL) {
    506 				p++;
    507 			} else {
    508 				vpp = hashvar(name);
    509 				for (vp = *vpp ; vp ; vp = vp->next) {
    510 					if (varequal(vp->text, name)) {
    511 						vp->flags |= flag;
    512 						goto found;
    513 					}
    514 				}
    515 			}
    516 			setvar(name, p, flag);
    517 found:;
    518 		}
    519 	} else {
    520 		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
    521 			for (vp = *vpp ; vp ; vp = vp->next) {
    522 				if (vp->flags & flag) {
    523 					for (p = vp->text ; *p != '=' ; p++)
    524 						out1c(*p);
    525 					out1c('\n');
    526 				}
    527 			}
    528 		}
    529 	}
    530 	return 0;
    531 }
    532 
    533 
    534 /*
    535  * The "local" command.
    536  */
    537 
    538 int
    539 localcmd(argc, argv)
    540 	int argc;
    541 	char **argv;
    542 {
    543 	char *name;
    544 
    545 	if (! in_function())
    546 		error("Not in a function");
    547 	while ((name = *argptr++) != NULL) {
    548 		mklocal(name);
    549 	}
    550 	return 0;
    551 }
    552 
    553 
    554 /*
    555  * Make a variable a local variable.  When a variable is made local, it's
    556  * value and flags are saved in a localvar structure.  The saved values
    557  * will be restored when the shell function returns.  We handle the name
    558  * "-" as a special case.
    559  */
    560 
    561 void
    562 mklocal(name)
    563 	char *name;
    564 	{
    565 	struct localvar *lvp;
    566 	struct var **vpp;
    567 	struct var *vp;
    568 
    569 	INTOFF;
    570 	lvp = ckmalloc(sizeof (struct localvar));
    571 	if (name[0] == '-' && name[1] == '\0') {
    572 		lvp->text = ckmalloc(sizeof optlist);
    573 		memcpy(lvp->text, optlist, sizeof optlist);
    574 		vp = NULL;
    575 	} else {
    576 		vpp = hashvar(name);
    577 		for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next);
    578 		if (vp == NULL) {
    579 			if (strchr(name, '='))
    580 				setvareq(savestr(name), VSTRFIXED);
    581 			else
    582 				setvar(name, NULL, VSTRFIXED);
    583 			vp = *vpp;	/* the new variable */
    584 			lvp->text = NULL;
    585 			lvp->flags = VUNSET;
    586 		} else {
    587 			lvp->text = vp->text;
    588 			lvp->flags = vp->flags;
    589 			vp->flags |= VSTRFIXED|VTEXTFIXED;
    590 			if (strchr(name, '='))
    591 				setvareq(savestr(name), 0);
    592 		}
    593 	}
    594 	lvp->vp = vp;
    595 	lvp->next = localvars;
    596 	localvars = lvp;
    597 	INTON;
    598 }
    599 
    600 
    601 /*
    602  * Called after a function returns.
    603  */
    604 
    605 void
    606 poplocalvars() {
    607 	struct localvar *lvp;
    608 	struct var *vp;
    609 
    610 	while ((lvp = localvars) != NULL) {
    611 		localvars = lvp->next;
    612 		vp = lvp->vp;
    613 		if (vp == NULL) {	/* $- saved */
    614 			memcpy(optlist, lvp->text, sizeof optlist);
    615 			ckfree(lvp->text);
    616 		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
    617 			(void)unsetvar(vp->text);
    618 		} else {
    619 			if ((vp->flags & VTEXTFIXED) == 0)
    620 				ckfree(vp->text);
    621 			vp->flags = lvp->flags;
    622 			vp->text = lvp->text;
    623 		}
    624 		ckfree(lvp);
    625 	}
    626 }
    627 
    628 
    629 int
    630 setvarcmd(argc, argv)
    631 	int argc;
    632 	char **argv;
    633 {
    634 	if (argc <= 2)
    635 		return unsetcmd(argc, argv);
    636 	else if (argc == 3)
    637 		setvar(argv[1], argv[2], 0);
    638 	else
    639 		error("List assignment not implemented");
    640 	return 0;
    641 }
    642 
    643 
    644 /*
    645  * The unset builtin command.  We unset the function before we unset the
    646  * variable to allow a function to be unset when there is a readonly variable
    647  * with the same name.
    648  */
    649 
    650 int
    651 unsetcmd(argc, argv)
    652 	int argc;
    653 	char **argv;
    654 {
    655 	char **ap;
    656 	int i;
    657 	int flg_func = 0;
    658 	int flg_var = 0;
    659 	int ret = 0;
    660 
    661 	while ((i = nextopt("vf")) != '\0') {
    662 		if (i == 'f')
    663 			flg_func = 1;
    664 		else
    665 			flg_var = 1;
    666 	}
    667 	if (flg_func == 0 && flg_var == 0)
    668 		flg_var = 1;
    669 
    670 	for (ap = argptr; *ap ; ap++) {
    671 		if (flg_func)
    672 			ret |= unsetfunc(*ap);
    673 		if (flg_var)
    674 			ret |= unsetvar(*ap);
    675 	}
    676 	return ret;
    677 }
    678 
    679 
    680 /*
    681  * Unset the specified variable.
    682  */
    683 
    684 int
    685 unsetvar(s)
    686 	char *s;
    687 	{
    688 	struct var **vpp;
    689 	struct var *vp;
    690 
    691 	vpp = hashvar(s);
    692 	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
    693 		if (varequal(vp->text, s)) {
    694 			if (vp->flags & VREADONLY)
    695 				return (1);
    696 			INTOFF;
    697 			if (*(strchr(vp->text, '=') + 1) != '\0')
    698 				setvar(s, nullstr, 0);
    699 			vp->flags &= ~VEXPORT;
    700 			vp->flags |= VUNSET;
    701 			if ((vp->flags & VSTRFIXED) == 0) {
    702 				if ((vp->flags & VTEXTFIXED) == 0)
    703 					ckfree(vp->text);
    704 				*vpp = vp->next;
    705 				ckfree(vp);
    706 			}
    707 			INTON;
    708 			return (0);
    709 		}
    710 	}
    711 
    712 	return (1);
    713 }
    714 
    715 
    716 
    717 /*
    718  * Find the appropriate entry in the hash table from the name.
    719  */
    720 
    721 STATIC struct var **
    722 hashvar(p)
    723 	char *p;
    724 	{
    725 	unsigned int hashval;
    726 
    727 	hashval = ((unsigned char) *p) << 4;
    728 	while (*p && *p != '=')
    729 		hashval += (unsigned char) *p++;
    730 	return &vartab[hashval % VTABSIZE];
    731 }
    732 
    733 
    734 
    735 /*
    736  * Returns true if the two strings specify the same varable.  The first
    737  * variable name is terminated by '='; the second may be terminated by
    738  * either '=' or '\0'.
    739  */
    740 
    741 STATIC int
    742 varequal(p, q)
    743 	char *p, *q;
    744 	{
    745 	while (*p == *q++) {
    746 		if (*p++ == '=')
    747 			return 1;
    748 	}
    749 	if (*p == '=' && *(q - 1) == '\0')
    750 		return 1;
    751 	return 0;
    752 }
    753