1 /* $NetBSD: var.c,v 1.19 1997/07/04 21:02:25 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 #include <sys/cdefs.h> 40 #ifndef lint 41 #if 0 42 static char sccsid[] = "@(#)var.c 8.3 (Berkeley) 5/4/95"; 43 #else 44 __RCSID("$NetBSD: var.c,v 1.19 1997/07/04 21:02:25 christos Exp $"); 45 #endif 46 #endif /* not lint */ 47 48 #include <unistd.h> 49 #include <stdlib.h> 50 51 /* 52 * Shell variables. 53 */ 54 55 #include "shell.h" 56 #include "output.h" 57 #include "expand.h" 58 #include "nodes.h" /* for other headers */ 59 #include "eval.h" /* defines cmdenviron */ 60 #include "exec.h" 61 #include "syntax.h" 62 #include "options.h" 63 #include "mail.h" 64 #include "var.h" 65 #include "memalloc.h" 66 #include "error.h" 67 #include "mystring.h" 68 #include "parser.h" 69 #ifndef SMALL 70 #include "myhistedit.h" 71 #endif 72 73 74 #define VTABSIZE 39 75 76 77 struct varinit { 78 struct var *var; 79 int flags; 80 char *text; 81 void (*func) __P((const char *)); 82 }; 83 84 85 #if ATTY 86 struct var vatty; 87 #endif 88 #ifndef SMALL 89 struct var vhistsize; 90 struct var vterm; 91 #endif 92 struct var vifs; 93 struct var vmail; 94 struct var vmpath; 95 struct var vpath; 96 struct var vps1; 97 struct var vps2; 98 struct var vvers; 99 struct var voptind; 100 101 const struct varinit varinit[] = { 102 #if ATTY 103 { &vatty, VSTRFIXED|VTEXTFIXED|VUNSET, "ATTY=", 104 NULL }, 105 #endif 106 #ifndef SMALL 107 { &vhistsize, VSTRFIXED|VTEXTFIXED|VUNSET, "HISTSIZE=", 108 sethistsize }, 109 #endif 110 { &vifs, VSTRFIXED|VTEXTFIXED, "IFS= \t\n", 111 NULL }, 112 { &vmail, VSTRFIXED|VTEXTFIXED|VUNSET, "MAIL=", 113 NULL }, 114 { &vmpath, VSTRFIXED|VTEXTFIXED|VUNSET, "MAILPATH=", 115 NULL }, 116 { &vpath, VSTRFIXED|VTEXTFIXED, "PATH=/bin:/usr/bin", 117 changepath }, 118 /* 119 * vps1 depends on uid 120 */ 121 { &vps2, VSTRFIXED|VTEXTFIXED, "PS2=> ", 122 NULL }, 123 #ifndef SMALL 124 { &vterm, VSTRFIXED|VTEXTFIXED|VUNSET, "TERM=", 125 setterm }, 126 #endif 127 { &voptind, VSTRFIXED|VTEXTFIXED, "OPTIND=1", 128 getoptsreset }, 129 { NULL, 0, NULL, 130 NULL } 131 }; 132 133 struct var *vartab[VTABSIZE]; 134 135 STATIC struct var **hashvar __P((char *)); 136 STATIC int varequal __P((char *, char *)); 137 138 /* 139 * Initialize the varable symbol tables and import the environment 140 */ 141 142 #ifdef mkinit 143 INCLUDE "var.h" 144 INIT { 145 char **envp; 146 extern char **environ; 147 148 initvar(); 149 for (envp = environ ; *envp ; envp++) { 150 if (strchr(*envp, '=')) { 151 setvareq(*envp, VEXPORT|VTEXTFIXED); 152 } 153 } 154 } 155 #endif 156 157 158 /* 159 * This routine initializes the builtin variables. It is called when the 160 * shell is initialized and again when a shell procedure is spawned. 161 */ 162 163 void 164 initvar() { 165 const struct varinit *ip; 166 struct var *vp; 167 struct var **vpp; 168 169 for (ip = varinit ; (vp = ip->var) != NULL ; ip++) { 170 if ((vp->flags & VEXPORT) == 0) { 171 vpp = hashvar(ip->text); 172 vp->next = *vpp; 173 *vpp = vp; 174 vp->text = ip->text; 175 vp->flags = ip->flags; 176 vp->func = ip->func; 177 } 178 } 179 /* 180 * PS1 depends on uid 181 */ 182 if ((vps1.flags & VEXPORT) == 0) { 183 vpp = hashvar("PS1="); 184 vps1.next = *vpp; 185 *vpp = &vps1; 186 vps1.text = geteuid() ? "PS1=$ " : "PS1=# "; 187 vps1.flags = VSTRFIXED|VTEXTFIXED; 188 } 189 } 190 191 /* 192 * Safe version of setvar, returns 1 on success 0 on failure. 193 */ 194 195 int 196 setvarsafe(name, val, flags) 197 char *name, *val; 198 int flags; 199 { 200 struct jmploc jmploc; 201 struct jmploc *volatile savehandler = handler; 202 int err = 0; 203 #ifdef __GNUC__ 204 (void) &err; 205 #endif 206 207 if (setjmp(jmploc.loc)) 208 err = 1; 209 else { 210 handler = &jmploc; 211 setvar(name, val, flags); 212 } 213 handler = savehandler; 214 return err; 215 } 216 217 /* 218 * Set the value of a variable. The flags argument is ored with the 219 * flags of the variable. If val is NULL, the variable is unset. 220 */ 221 222 void 223 setvar(name, val, flags) 224 char *name, *val; 225 int flags; 226 { 227 char *p, *q; 228 int len; 229 int namelen; 230 char *nameeq; 231 int isbad; 232 233 isbad = 0; 234 p = name; 235 if (! is_name(*p)) 236 isbad = 1; 237 p++; 238 for (;;) { 239 if (! is_in_name(*p)) { 240 if (*p == '\0' || *p == '=') 241 break; 242 isbad = 1; 243 } 244 p++; 245 } 246 namelen = p - name; 247 if (isbad) 248 error("%.*s: bad variable name", namelen, name); 249 len = namelen + 2; /* 2 is space for '=' and '\0' */ 250 if (val == NULL) { 251 flags |= VUNSET; 252 } else { 253 len += strlen(val); 254 } 255 p = nameeq = ckmalloc(len); 256 q = name; 257 while (--namelen >= 0) 258 *p++ = *q++; 259 *p++ = '='; 260 *p = '\0'; 261 if (val) 262 scopy(val, p); 263 setvareq(nameeq, flags); 264 } 265 266 267 268 /* 269 * Same as setvar except that the variable and value are passed in 270 * the first argument as name=value. Since the first argument will 271 * be actually stored in the table, it should not be a string that 272 * will go away. 273 */ 274 275 void 276 setvareq(s, flags) 277 char *s; 278 int flags; 279 { 280 struct var *vp, **vpp; 281 282 vpp = hashvar(s); 283 for (vp = *vpp ; vp ; vp = vp->next) { 284 if (varequal(s, vp->text)) { 285 if (vp->flags & VREADONLY) { 286 size_t len = strchr(s, '=') - s; 287 error("%.*s: is read only", len, s); 288 } 289 INTOFF; 290 291 if (vp->func && (flags & VNOFUNC) == 0) 292 (*vp->func)(strchr(s, '=') + 1); 293 294 if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0) 295 ckfree(vp->text); 296 297 vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET); 298 vp->flags |= flags; 299 vp->text = s; 300 301 /* 302 * We could roll this to a function, to handle it as 303 * a regular variable function callback, but why bother? 304 */ 305 if (vp == &vmpath || (vp == &vmail && ! mpathset())) 306 chkmail(1); 307 INTON; 308 return; 309 } 310 } 311 /* not found */ 312 vp = ckmalloc(sizeof (*vp)); 313 vp->flags = flags; 314 vp->text = s; 315 vp->next = *vpp; 316 vp->func = NULL; 317 *vpp = vp; 318 } 319 320 321 322 /* 323 * Process a linked list of variable assignments. 324 */ 325 326 void 327 listsetvar(list) 328 struct strlist *list; 329 { 330 struct strlist *lp; 331 332 INTOFF; 333 for (lp = list ; lp ; lp = lp->next) { 334 setvareq(savestr(lp->text), 0); 335 } 336 INTON; 337 } 338 339 340 341 /* 342 * Find the value of a variable. Returns NULL if not set. 343 */ 344 345 char * 346 lookupvar(name) 347 char *name; 348 { 349 struct var *v; 350 351 for (v = *hashvar(name) ; v ; v = v->next) { 352 if (varequal(v->text, name)) { 353 if (v->flags & VUNSET) 354 return NULL; 355 return strchr(v->text, '=') + 1; 356 } 357 } 358 return NULL; 359 } 360 361 362 363 /* 364 * Search the environment of a builtin command. If the second argument 365 * is nonzero, return the value of a variable even if it hasn't been 366 * exported. 367 */ 368 369 char * 370 bltinlookup(name, doall) 371 char *name; 372 int doall; 373 { 374 struct strlist *sp; 375 struct var *v; 376 377 for (sp = cmdenviron ; sp ; sp = sp->next) { 378 if (varequal(sp->text, name)) 379 return strchr(sp->text, '=') + 1; 380 } 381 for (v = *hashvar(name) ; v ; v = v->next) { 382 if (varequal(v->text, name)) { 383 if ((v->flags & VUNSET) 384 || (!doall && (v->flags & VEXPORT) == 0)) 385 return NULL; 386 return strchr(v->text, '=') + 1; 387 } 388 } 389 return NULL; 390 } 391 392 393 394 /* 395 * Generate a list of exported variables. This routine is used to construct 396 * the third argument to execve when executing a program. 397 */ 398 399 char ** 400 environment() { 401 int nenv; 402 struct var **vpp; 403 struct var *vp; 404 char **env, **ep; 405 406 nenv = 0; 407 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 408 for (vp = *vpp ; vp ; vp = vp->next) 409 if (vp->flags & VEXPORT) 410 nenv++; 411 } 412 ep = env = stalloc((nenv + 1) * sizeof *env); 413 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 414 for (vp = *vpp ; vp ; vp = vp->next) 415 if (vp->flags & VEXPORT) 416 *ep++ = vp->text; 417 } 418 *ep = NULL; 419 return env; 420 } 421 422 423 /* 424 * Called when a shell procedure is invoked to clear out nonexported 425 * variables. It is also necessary to reallocate variables of with 426 * VSTACK set since these are currently allocated on the stack. 427 */ 428 429 #ifdef mkinit 430 MKINIT void shprocvar __P((void)); 431 432 SHELLPROC { 433 shprocvar(); 434 } 435 #endif 436 437 void 438 shprocvar() { 439 struct var **vpp; 440 struct var *vp, **prev; 441 442 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 443 for (prev = vpp ; (vp = *prev) != NULL ; ) { 444 if ((vp->flags & VEXPORT) == 0) { 445 *prev = vp->next; 446 if ((vp->flags & VTEXTFIXED) == 0) 447 ckfree(vp->text); 448 if ((vp->flags & VSTRFIXED) == 0) 449 ckfree(vp); 450 } else { 451 if (vp->flags & VSTACK) { 452 vp->text = savestr(vp->text); 453 vp->flags &=~ VSTACK; 454 } 455 prev = &vp->next; 456 } 457 } 458 } 459 initvar(); 460 } 461 462 463 464 /* 465 * Command to list all variables which are set. Currently this command 466 * is invoked from the set command when the set command is called without 467 * any variables. 468 */ 469 470 int 471 showvarscmd(argc, argv) 472 int argc; 473 char **argv; 474 { 475 struct var **vpp; 476 struct var *vp; 477 478 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 479 for (vp = *vpp ; vp ; vp = vp->next) { 480 if ((vp->flags & VUNSET) == 0) 481 out1fmt("%s\n", vp->text); 482 } 483 } 484 return 0; 485 } 486 487 488 489 /* 490 * The export and readonly commands. 491 */ 492 493 int 494 exportcmd(argc, argv) 495 int argc; 496 char **argv; 497 { 498 struct var **vpp; 499 struct var *vp; 500 char *name; 501 char *p; 502 int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT; 503 504 listsetvar(cmdenviron); 505 if (argc > 1) { 506 while ((name = *argptr++) != NULL) { 507 if ((p = strchr(name, '=')) != NULL) { 508 p++; 509 } else { 510 vpp = hashvar(name); 511 for (vp = *vpp ; vp ; vp = vp->next) { 512 if (varequal(vp->text, name)) { 513 vp->flags |= flag; 514 goto found; 515 } 516 } 517 } 518 setvar(name, p, flag); 519 found:; 520 } 521 } else { 522 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 523 for (vp = *vpp ; vp ; vp = vp->next) { 524 if (vp->flags & flag) { 525 for (p = vp->text ; *p != '=' ; p++) 526 out1c(*p); 527 out1c('\n'); 528 } 529 } 530 } 531 } 532 return 0; 533 } 534 535 536 /* 537 * The "local" command. 538 */ 539 540 int 541 localcmd(argc, argv) 542 int argc; 543 char **argv; 544 { 545 char *name; 546 547 if (! in_function()) 548 error("Not in a function"); 549 while ((name = *argptr++) != NULL) { 550 mklocal(name); 551 } 552 return 0; 553 } 554 555 556 /* 557 * Make a variable a local variable. When a variable is made local, it's 558 * value and flags are saved in a localvar structure. The saved values 559 * will be restored when the shell function returns. We handle the name 560 * "-" as a special case. 561 */ 562 563 void 564 mklocal(name) 565 char *name; 566 { 567 struct localvar *lvp; 568 struct var **vpp; 569 struct var *vp; 570 571 INTOFF; 572 lvp = ckmalloc(sizeof (struct localvar)); 573 if (name[0] == '-' && name[1] == '\0') { 574 lvp->text = ckmalloc(sizeof optlist); 575 memcpy(lvp->text, optlist, sizeof optlist); 576 vp = NULL; 577 } else { 578 vpp = hashvar(name); 579 for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next); 580 if (vp == NULL) { 581 if (strchr(name, '=')) 582 setvareq(savestr(name), VSTRFIXED); 583 else 584 setvar(name, NULL, VSTRFIXED); 585 vp = *vpp; /* the new variable */ 586 lvp->text = NULL; 587 lvp->flags = VUNSET; 588 } else { 589 lvp->text = vp->text; 590 lvp->flags = vp->flags; 591 vp->flags |= VSTRFIXED|VTEXTFIXED; 592 if (strchr(name, '=')) 593 setvareq(savestr(name), 0); 594 } 595 } 596 lvp->vp = vp; 597 lvp->next = localvars; 598 localvars = lvp; 599 INTON; 600 } 601 602 603 /* 604 * Called after a function returns. 605 */ 606 607 void 608 poplocalvars() { 609 struct localvar *lvp; 610 struct var *vp; 611 612 while ((lvp = localvars) != NULL) { 613 localvars = lvp->next; 614 vp = lvp->vp; 615 if (vp == NULL) { /* $- saved */ 616 memcpy(optlist, lvp->text, sizeof optlist); 617 ckfree(lvp->text); 618 } else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) { 619 (void)unsetvar(vp->text); 620 } else { 621 if ((vp->flags & VTEXTFIXED) == 0) 622 ckfree(vp->text); 623 vp->flags = lvp->flags; 624 vp->text = lvp->text; 625 } 626 ckfree(lvp); 627 } 628 } 629 630 631 int 632 setvarcmd(argc, argv) 633 int argc; 634 char **argv; 635 { 636 if (argc <= 2) 637 return unsetcmd(argc, argv); 638 else if (argc == 3) 639 setvar(argv[1], argv[2], 0); 640 else 641 error("List assignment not implemented"); 642 return 0; 643 } 644 645 646 /* 647 * The unset builtin command. We unset the function before we unset the 648 * variable to allow a function to be unset when there is a readonly variable 649 * with the same name. 650 */ 651 652 int 653 unsetcmd(argc, argv) 654 int argc; 655 char **argv; 656 { 657 char **ap; 658 int i; 659 int flg_func = 0; 660 int flg_var = 0; 661 int ret = 0; 662 663 while ((i = nextopt("vf")) != '\0') { 664 if (i == 'f') 665 flg_func = 1; 666 else 667 flg_var = 1; 668 } 669 if (flg_func == 0 && flg_var == 0) 670 flg_var = 1; 671 672 for (ap = argptr; *ap ; ap++) { 673 if (flg_func) 674 ret |= unsetfunc(*ap); 675 if (flg_var) 676 ret |= unsetvar(*ap); 677 } 678 return ret; 679 } 680 681 682 /* 683 * Unset the specified variable. 684 */ 685 686 int 687 unsetvar(s) 688 char *s; 689 { 690 struct var **vpp; 691 struct var *vp; 692 693 vpp = hashvar(s); 694 for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) { 695 if (varequal(vp->text, s)) { 696 if (vp->flags & VREADONLY) 697 return (1); 698 INTOFF; 699 if (*(strchr(vp->text, '=') + 1) != '\0') 700 setvar(s, nullstr, 0); 701 vp->flags &= ~VEXPORT; 702 vp->flags |= VUNSET; 703 if ((vp->flags & VSTRFIXED) == 0) { 704 if ((vp->flags & VTEXTFIXED) == 0) 705 ckfree(vp->text); 706 *vpp = vp->next; 707 ckfree(vp); 708 } 709 INTON; 710 return (0); 711 } 712 } 713 714 return (1); 715 } 716 717 718 719 /* 720 * Find the appropriate entry in the hash table from the name. 721 */ 722 723 STATIC struct var ** 724 hashvar(p) 725 char *p; 726 { 727 unsigned int hashval; 728 729 hashval = ((unsigned char) *p) << 4; 730 while (*p && *p != '=') 731 hashval += (unsigned char) *p++; 732 return &vartab[hashval % VTABSIZE]; 733 } 734 735 736 737 /* 738 * Returns true if the two strings specify the same varable. The first 739 * variable name is terminated by '='; the second may be terminated by 740 * either '=' or '\0'. 741 */ 742 743 STATIC int 744 varequal(p, q) 745 char *p, *q; 746 { 747 while (*p == *q++) { 748 if (*p++ == '=') 749 return 1; 750 } 751 if (*p == '=' && *(q - 1) == '\0') 752 return 1; 753 return 0; 754 } 755