1 /* $NetBSD: var.c,v 1.13 1995/05/11 21:30:39 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 1.13 1995/05/11 21:30:39 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 #ifndef NO_HISTORY 68 #include "myhistedit.h" 69 #endif 70 71 72 #define VTABSIZE 39 73 74 75 struct varinit { 76 struct var *var; 77 int flags; 78 char *text; 79 }; 80 81 82 #if ATTY 83 struct var vatty; 84 #endif 85 #ifndef NO_HISTORY 86 struct var vhistsize; 87 #endif 88 struct var vifs; 89 struct var vmail; 90 struct var vmpath; 91 struct var vpath; 92 struct var vps1; 93 struct var vps2; 94 struct var vvers; 95 #if ATTY 96 struct var vterm; 97 #endif 98 99 const struct varinit varinit[] = { 100 #if ATTY 101 {&vatty, VSTRFIXED|VTEXTFIXED|VUNSET, "ATTY="}, 102 #endif 103 #ifndef NO_HISTORY 104 {&vhistsize, VSTRFIXED|VTEXTFIXED|VUNSET, "HISTSIZE="}, 105 #endif 106 {&vifs, VSTRFIXED|VTEXTFIXED, "IFS= \t\n"}, 107 {&vmail, VSTRFIXED|VTEXTFIXED|VUNSET, "MAIL="}, 108 {&vmpath, VSTRFIXED|VTEXTFIXED|VUNSET, "MAILPATH="}, 109 {&vpath, VSTRFIXED|VTEXTFIXED, "PATH=/bin:/usr/bin"}, 110 /* 111 * vps1 depends on uid 112 */ 113 {&vps2, VSTRFIXED|VTEXTFIXED, "PS2=> "}, 114 #if ATTY 115 {&vterm, VSTRFIXED|VTEXTFIXED|VUNSET, "TERM="}, 116 #endif 117 {NULL, 0, NULL} 118 }; 119 120 struct var *vartab[VTABSIZE]; 121 122 STATIC int unsetvar __P((char *)); 123 STATIC struct var **hashvar __P((char *)); 124 STATIC int varequal __P((char *, char *)); 125 126 /* 127 * Initialize the varable symbol tables and import the environment 128 */ 129 130 #ifdef mkinit 131 INCLUDE "var.h" 132 INIT { 133 char **envp; 134 extern char **environ; 135 136 initvar(); 137 for (envp = environ ; *envp ; envp++) { 138 if (strchr(*envp, '=')) { 139 setvareq(*envp, VEXPORT|VTEXTFIXED); 140 } 141 } 142 } 143 #endif 144 145 146 /* 147 * This routine initializes the builtin variables. It is called when the 148 * shell is initialized and again when a shell procedure is spawned. 149 */ 150 151 void 152 initvar() { 153 const struct varinit *ip; 154 struct var *vp; 155 struct var **vpp; 156 157 for (ip = varinit ; (vp = ip->var) != NULL ; ip++) { 158 if ((vp->flags & VEXPORT) == 0) { 159 vpp = hashvar(ip->text); 160 vp->next = *vpp; 161 *vpp = vp; 162 vp->text = ip->text; 163 vp->flags = ip->flags; 164 } 165 } 166 /* 167 * PS1 depends on uid 168 */ 169 if ((vps1.flags & VEXPORT) == 0) { 170 vpp = hashvar("PS1="); 171 vps1.next = *vpp; 172 *vpp = &vps1; 173 vps1.text = geteuid() ? "PS1=$ " : "PS1=# "; 174 vps1.flags = VSTRFIXED|VTEXTFIXED; 175 } 176 } 177 178 /* 179 * Set the value of a variable. The flags argument is ored with the 180 * flags of the variable. If val is NULL, the variable is unset. 181 */ 182 183 void 184 setvar(name, val, flags) 185 char *name, *val; 186 int flags; 187 { 188 char *p, *q; 189 int len; 190 int namelen; 191 char *nameeq; 192 int isbad; 193 194 isbad = 0; 195 p = name; 196 if (! is_name(*p++)) 197 isbad = 1; 198 for (;;) { 199 if (! is_in_name(*p)) { 200 if (*p == '\0' || *p == '=') 201 break; 202 isbad = 1; 203 } 204 p++; 205 } 206 namelen = p - name; 207 if (isbad) 208 error("%.*s: bad variable name", namelen, name); 209 len = namelen + 2; /* 2 is space for '=' and '\0' */ 210 if (val == NULL) { 211 flags |= VUNSET; 212 } else { 213 len += strlen(val); 214 } 215 p = nameeq = ckmalloc(len); 216 q = name; 217 while (--namelen >= 0) 218 *p++ = *q++; 219 *p++ = '='; 220 *p = '\0'; 221 if (val) 222 scopy(val, p); 223 setvareq(nameeq, flags); 224 } 225 226 227 228 /* 229 * Same as setvar except that the variable and value are passed in 230 * the first argument as name=value. Since the first argument will 231 * be actually stored in the table, it should not be a string that 232 * will go away. 233 */ 234 235 void 236 setvareq(s, flags) 237 char *s; 238 int flags; 239 { 240 struct var *vp, **vpp; 241 242 vpp = hashvar(s); 243 for (vp = *vpp ; vp ; vp = vp->next) { 244 if (varequal(s, vp->text)) { 245 if (vp->flags & VREADONLY) { 246 int len = strchr(s, '=') - s; 247 error("%.*s: is read only", len, s); 248 } 249 INTOFF; 250 if (vp == &vpath) 251 changepath(s + 5); /* 5 = strlen("PATH=") */ 252 if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0) 253 ckfree(vp->text); 254 vp->flags &=~ (VTEXTFIXED|VSTACK|VUNSET); 255 vp->flags |= flags; 256 vp->text = s; 257 if (vp == &vmpath || (vp == &vmail && ! mpathset())) 258 chkmail(1); 259 #ifndef NO_HISTORY 260 if (vp == &vhistsize) 261 sethistsize(); 262 #endif 263 INTON; 264 return; 265 } 266 } 267 /* not found */ 268 vp = ckmalloc(sizeof (*vp)); 269 vp->flags = flags; 270 vp->text = s; 271 vp->next = *vpp; 272 *vpp = vp; 273 } 274 275 276 277 /* 278 * Process a linked list of variable assignments. 279 */ 280 281 void 282 listsetvar(list) 283 struct strlist *list; 284 { 285 struct strlist *lp; 286 287 INTOFF; 288 for (lp = list ; lp ; lp = lp->next) { 289 setvareq(savestr(lp->text), 0); 290 } 291 INTON; 292 } 293 294 295 296 /* 297 * Find the value of a variable. Returns NULL if not set. 298 */ 299 300 char * 301 lookupvar(name) 302 char *name; 303 { 304 struct var *v; 305 306 for (v = *hashvar(name) ; v ; v = v->next) { 307 if (varequal(v->text, name)) { 308 if (v->flags & VUNSET) 309 return NULL; 310 return strchr(v->text, '=') + 1; 311 } 312 } 313 return NULL; 314 } 315 316 317 318 /* 319 * Search the environment of a builtin command. If the second argument 320 * is nonzero, return the value of a variable even if it hasn't been 321 * exported. 322 */ 323 324 char * 325 bltinlookup(name, doall) 326 char *name; 327 int doall; 328 { 329 struct strlist *sp; 330 struct var *v; 331 332 for (sp = cmdenviron ; sp ; sp = sp->next) { 333 if (varequal(sp->text, name)) 334 return strchr(sp->text, '=') + 1; 335 } 336 for (v = *hashvar(name) ; v ; v = v->next) { 337 if (varequal(v->text, name)) { 338 if ((v->flags & VUNSET) 339 || (!doall && (v->flags & VEXPORT) == 0)) 340 return NULL; 341 return strchr(v->text, '=') + 1; 342 } 343 } 344 return NULL; 345 } 346 347 348 349 /* 350 * Generate a list of exported variables. This routine is used to construct 351 * the third argument to execve when executing a program. 352 */ 353 354 char ** 355 environment() { 356 int nenv; 357 struct var **vpp; 358 struct var *vp; 359 char **env, **ep; 360 361 nenv = 0; 362 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 363 for (vp = *vpp ; vp ; vp = vp->next) 364 if (vp->flags & VEXPORT) 365 nenv++; 366 } 367 ep = env = stalloc((nenv + 1) * sizeof *env); 368 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 369 for (vp = *vpp ; vp ; vp = vp->next) 370 if (vp->flags & VEXPORT) 371 *ep++ = vp->text; 372 } 373 *ep = NULL; 374 return env; 375 } 376 377 378 /* 379 * Called when a shell procedure is invoked to clear out nonexported 380 * variables. It is also necessary to reallocate variables of with 381 * VSTACK set since these are currently allocated on the stack. 382 */ 383 384 #ifdef mkinit 385 MKINIT void shprocvar(); 386 387 SHELLPROC { 388 shprocvar(); 389 } 390 #endif 391 392 void 393 shprocvar() { 394 struct var **vpp; 395 struct var *vp, **prev; 396 397 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 398 for (prev = vpp ; (vp = *prev) != NULL ; ) { 399 if ((vp->flags & VEXPORT) == 0) { 400 *prev = vp->next; 401 if ((vp->flags & VTEXTFIXED) == 0) 402 ckfree(vp->text); 403 if ((vp->flags & VSTRFIXED) == 0) 404 ckfree(vp); 405 } else { 406 if (vp->flags & VSTACK) { 407 vp->text = savestr(vp->text); 408 vp->flags &=~ VSTACK; 409 } 410 prev = &vp->next; 411 } 412 } 413 } 414 initvar(); 415 } 416 417 418 419 /* 420 * Command to list all variables which are set. Currently this command 421 * is invoked from the set command when the set command is called without 422 * any variables. 423 */ 424 425 int 426 showvarscmd(argc, argv) 427 int argc; 428 char **argv; 429 { 430 struct var **vpp; 431 struct var *vp; 432 433 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 434 for (vp = *vpp ; vp ; vp = vp->next) { 435 if ((vp->flags & VUNSET) == 0) 436 out1fmt("%s\n", vp->text); 437 } 438 } 439 return 0; 440 } 441 442 443 444 /* 445 * The export and readonly commands. 446 */ 447 448 int 449 exportcmd(argc, argv) 450 int argc; 451 char **argv; 452 { 453 struct var **vpp; 454 struct var *vp; 455 char *name; 456 char *p; 457 int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT; 458 459 listsetvar(cmdenviron); 460 if (argc > 1) { 461 while ((name = *argptr++) != NULL) { 462 if ((p = strchr(name, '=')) != NULL) { 463 p++; 464 } else { 465 vpp = hashvar(name); 466 for (vp = *vpp ; vp ; vp = vp->next) { 467 if (varequal(vp->text, name)) { 468 vp->flags |= flag; 469 goto found; 470 } 471 } 472 } 473 setvar(name, p, flag); 474 found:; 475 } 476 } else { 477 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 478 for (vp = *vpp ; vp ; vp = vp->next) { 479 if (vp->flags & flag) { 480 for (p = vp->text ; *p != '=' ; p++) 481 out1c(*p); 482 out1c('\n'); 483 } 484 } 485 } 486 } 487 return 0; 488 } 489 490 491 /* 492 * The "local" command. 493 */ 494 495 int 496 localcmd(argc, argv) 497 int argc; 498 char **argv; 499 { 500 char *name; 501 502 if (! in_function()) 503 error("Not in a function"); 504 while ((name = *argptr++) != NULL) { 505 mklocal(name); 506 } 507 return 0; 508 } 509 510 511 /* 512 * Make a variable a local variable. When a variable is made local, it's 513 * value and flags are saved in a localvar structure. The saved values 514 * will be restored when the shell function returns. We handle the name 515 * "-" as a special case. 516 */ 517 518 void 519 mklocal(name) 520 char *name; 521 { 522 struct localvar *lvp; 523 struct var **vpp; 524 struct var *vp; 525 526 INTOFF; 527 lvp = ckmalloc(sizeof (struct localvar)); 528 if (name[0] == '-' && name[1] == '\0') { 529 lvp->text = ckmalloc(sizeof optlist); 530 memcpy(lvp->text, optlist, sizeof optlist); 531 vp = NULL; 532 } else { 533 vpp = hashvar(name); 534 for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next); 535 if (vp == NULL) { 536 if (strchr(name, '=')) 537 setvareq(savestr(name), VSTRFIXED); 538 else 539 setvar(name, NULL, VSTRFIXED); 540 vp = *vpp; /* the new variable */ 541 lvp->text = NULL; 542 lvp->flags = VUNSET; 543 } else { 544 lvp->text = vp->text; 545 lvp->flags = vp->flags; 546 vp->flags |= VSTRFIXED|VTEXTFIXED; 547 if (strchr(name, '=')) 548 setvareq(savestr(name), 0); 549 } 550 } 551 lvp->vp = vp; 552 lvp->next = localvars; 553 localvars = lvp; 554 INTON; 555 } 556 557 558 /* 559 * Called after a function returns. 560 */ 561 562 void 563 poplocalvars() { 564 struct localvar *lvp; 565 struct var *vp; 566 567 while ((lvp = localvars) != NULL) { 568 localvars = lvp->next; 569 vp = lvp->vp; 570 if (vp == NULL) { /* $- saved */ 571 memcpy(optlist, lvp->text, sizeof optlist); 572 ckfree(lvp->text); 573 } else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) { 574 (void)unsetvar(vp->text); 575 } else { 576 if ((vp->flags & VTEXTFIXED) == 0) 577 ckfree(vp->text); 578 vp->flags = lvp->flags; 579 vp->text = lvp->text; 580 } 581 ckfree(lvp); 582 } 583 } 584 585 586 int 587 setvarcmd(argc, argv) 588 int argc; 589 char **argv; 590 { 591 if (argc <= 2) 592 return unsetcmd(argc, argv); 593 else if (argc == 3) 594 setvar(argv[1], argv[2], 0); 595 else 596 error("List assignment not implemented"); 597 return 0; 598 } 599 600 601 /* 602 * The unset builtin command. We unset the function before we unset the 603 * variable to allow a function to be unset when there is a readonly variable 604 * with the same name. 605 */ 606 607 int 608 unsetcmd(argc, argv) 609 int argc; 610 char **argv; 611 { 612 char **ap; 613 int i; 614 int flg_func = 0; 615 int flg_var = 0; 616 int ret = 0; 617 618 while ((i = nextopt("vf")) != '\0') { 619 if (i == 'f') 620 flg_func = 1; 621 else 622 flg_var = 1; 623 } 624 if (flg_func == 0 && flg_var == 0) 625 flg_var = 1; 626 627 for (ap = argptr; *ap ; ap++) { 628 if (flg_func) 629 ret |= unsetfunc(*ap); 630 if (flg_var) 631 ret |= unsetvar(*ap); 632 } 633 return ret; 634 } 635 636 637 /* 638 * Unset the specified variable. 639 */ 640 641 STATIC int 642 unsetvar(s) 643 char *s; 644 { 645 struct var **vpp; 646 struct var *vp; 647 648 vpp = hashvar(s); 649 for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) { 650 if (varequal(vp->text, s)) { 651 if (vp->flags & VREADONLY) 652 return (1); 653 INTOFF; 654 if (*(strchr(vp->text, '=') + 1) != '\0') 655 setvar(s, nullstr, 0); 656 vp->flags &=~ VEXPORT; 657 vp->flags |= VUNSET; 658 if ((vp->flags & VSTRFIXED) == 0) { 659 if ((vp->flags & VTEXTFIXED) == 0) 660 ckfree(vp->text); 661 *vpp = vp->next; 662 ckfree(vp); 663 } 664 INTON; 665 return (0); 666 } 667 } 668 669 return (1); 670 } 671 672 673 674 /* 675 * Find the appropriate entry in the hash table from the name. 676 */ 677 678 STATIC struct var ** 679 hashvar(p) 680 register char *p; 681 { 682 unsigned int hashval; 683 684 hashval = *p << 4; 685 while (*p && *p != '=') 686 hashval += *p++; 687 return &vartab[hashval % VTABSIZE]; 688 } 689 690 691 692 /* 693 * Returns true if the two strings specify the same varable. The first 694 * variable name is terminated by '='; the second may be terminated by 695 * either '=' or '\0'. 696 */ 697 698 STATIC int 699 varequal(p, q) 700 register char *p, *q; 701 { 702 while (*p == *q++) { 703 if (*p++ == '=') 704 return 1; 705 } 706 if (*p == '=' && *(q - 1) == '\0') 707 return 1; 708 return 0; 709 } 710