1 /* $NetBSD: var.c,v 1.32 2003/01/22 20:36:04 dsl 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 1.32 2003/01/22 20:36:04 dsl Exp $"); 45 #endif 46 #endif /* not lint */ 47 48 #include <unistd.h> 49 #include <stdlib.h> 50 #include <paths.h> 51 52 /* 53 * Shell variables. 54 */ 55 56 #include "shell.h" 57 #include "output.h" 58 #include "expand.h" 59 #include "nodes.h" /* for other headers */ 60 #include "eval.h" /* defines cmdenviron */ 61 #include "exec.h" 62 #include "syntax.h" 63 #include "options.h" 64 #include "mail.h" 65 #include "var.h" 66 #include "memalloc.h" 67 #include "error.h" 68 #include "mystring.h" 69 #include "parser.h" 70 #include "show.h" 71 #ifndef SMALL 72 #include "myhistedit.h" 73 #endif 74 75 76 #define VTABSIZE 39 77 78 79 struct varinit { 80 struct var *var; 81 int flags; 82 const char *text; 83 void (*func)(const char *); 84 }; 85 86 87 #if ATTY 88 struct var vatty; 89 #endif 90 #ifndef SMALL 91 struct var vhistsize; 92 struct var vterm; 93 #endif 94 struct var vifs; 95 struct var vmail; 96 struct var vmpath; 97 struct var vpath; 98 struct var vps1; 99 struct var vps2; 100 struct var vps4; 101 struct var vvers; 102 struct var voptind; 103 104 const struct varinit varinit[] = { 105 #if ATTY 106 { &vatty, VSTRFIXED|VTEXTFIXED|VUNSET, "ATTY=", 107 NULL }, 108 #endif 109 #ifndef SMALL 110 { &vhistsize, VSTRFIXED|VTEXTFIXED|VUNSET, "HISTSIZE=", 111 sethistsize }, 112 #endif 113 { &vifs, VSTRFIXED|VTEXTFIXED, "IFS= \t\n", 114 NULL }, 115 { &vmail, VSTRFIXED|VTEXTFIXED|VUNSET, "MAIL=", 116 NULL }, 117 { &vmpath, VSTRFIXED|VTEXTFIXED|VUNSET, "MAILPATH=", 118 NULL }, 119 { &vpath, VSTRFIXED|VTEXTFIXED, "PATH=" _PATH_DEFPATH, 120 changepath }, 121 /* 122 * vps1 depends on uid 123 */ 124 { &vps2, VSTRFIXED|VTEXTFIXED, "PS2=> ", 125 NULL }, 126 { &vps4, VSTRFIXED|VTEXTFIXED, "PS4=+ ", 127 NULL }, 128 #ifndef SMALL 129 { &vterm, VSTRFIXED|VTEXTFIXED|VUNSET, "TERM=", 130 setterm }, 131 #endif 132 { &voptind, VSTRFIXED|VTEXTFIXED|VNOFUNC, "OPTIND=1", 133 getoptsreset }, 134 { NULL, 0, NULL, 135 NULL } 136 }; 137 138 struct var *vartab[VTABSIZE]; 139 140 STATIC struct var **hashvar(const char *); 141 STATIC int varequal(const char *, const char *); 142 143 /* 144 * Initialize the varable symbol tables and import the environment 145 */ 146 147 #ifdef mkinit 148 INCLUDE "var.h" 149 MKINIT char **environ; 150 INIT { 151 char **envp; 152 153 initvar(); 154 for (envp = environ ; *envp ; envp++) { 155 if (strchr(*envp, '=')) { 156 setvareq(*envp, VEXPORT|VTEXTFIXED); 157 } 158 } 159 } 160 #endif 161 162 163 /* 164 * This routine initializes the builtin variables. It is called when the 165 * shell is initialized and again when a shell procedure is spawned. 166 */ 167 168 void 169 initvar(void) 170 { 171 const struct varinit *ip; 172 struct var *vp; 173 struct var **vpp; 174 175 for (ip = varinit ; (vp = ip->var) != NULL ; ip++) { 176 if ((vp->flags & VEXPORT) == 0) { 177 vpp = hashvar(ip->text); 178 vp->next = *vpp; 179 *vpp = vp; 180 vp->text = strdup(ip->text); 181 vp->flags = ip->flags; 182 vp->func = ip->func; 183 } 184 } 185 /* 186 * PS1 depends on uid 187 */ 188 if ((vps1.flags & VEXPORT) == 0) { 189 vpp = hashvar("PS1="); 190 vps1.next = *vpp; 191 *vpp = &vps1; 192 vps1.text = strdup(geteuid() ? "PS1=$ " : "PS1=# "); 193 vps1.flags = VSTRFIXED|VTEXTFIXED; 194 } 195 } 196 197 /* 198 * Safe version of setvar, returns 1 on success 0 on failure. 199 */ 200 201 int 202 setvarsafe(const char *name, const char *val, int flags) 203 { 204 struct jmploc jmploc; 205 struct jmploc *volatile savehandler = handler; 206 int err = 0; 207 #ifdef __GNUC__ 208 (void) &err; 209 #endif 210 211 if (setjmp(jmploc.loc)) 212 err = 1; 213 else { 214 handler = &jmploc; 215 setvar(name, val, flags); 216 } 217 handler = savehandler; 218 return err; 219 } 220 221 /* 222 * Set the value of a variable. The flags argument is ored with the 223 * flags of the variable. If val is NULL, the variable is unset. 224 */ 225 226 void 227 setvar(const char *name, const char *val, int flags) 228 { 229 const char *p; 230 const char *q; 231 char *d; 232 int len; 233 int namelen; 234 char *nameeq; 235 int isbad; 236 237 isbad = 0; 238 p = name; 239 if (! is_name(*p)) 240 isbad = 1; 241 p++; 242 for (;;) { 243 if (! is_in_name(*p)) { 244 if (*p == '\0' || *p == '=') 245 break; 246 isbad = 1; 247 } 248 p++; 249 } 250 namelen = p - name; 251 if (isbad) 252 error("%.*s: bad variable name", namelen, name); 253 len = namelen + 2; /* 2 is space for '=' and '\0' */ 254 if (val == NULL) { 255 flags |= VUNSET; 256 } else { 257 len += strlen(val); 258 } 259 d = nameeq = ckmalloc(len); 260 q = name; 261 while (--namelen >= 0) 262 *d++ = *q++; 263 *d++ = '='; 264 *d = '\0'; 265 if (val) 266 scopy(val, d); 267 setvareq(nameeq, flags); 268 } 269 270 271 272 /* 273 * Same as setvar except that the variable and value are passed in 274 * the first argument as name=value. Since the first argument will 275 * be actually stored in the table, it should not be a string that 276 * will go away. 277 */ 278 279 void 280 setvareq(char *s, int flags) 281 { 282 struct var *vp, **vpp; 283 284 if (aflag) 285 flags |= VEXPORT; 286 vpp = hashvar(s); 287 for (vp = *vpp ; vp ; vp = vp->next) { 288 if (varequal(s, vp->text)) { 289 if (vp->flags & VREADONLY) { 290 size_t len = strchr(s, '=') - s; 291 error("%.*s: is read only", len, s); 292 } 293 if (flags & VNOSET) 294 return; 295 INTOFF; 296 297 if (vp->func && (flags & VNOFUNC) == 0) 298 (*vp->func)(strchr(s, '=') + 1); 299 300 if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0) 301 ckfree(vp->text); 302 303 vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET); 304 vp->flags |= flags & ~VNOFUNC; 305 vp->text = s; 306 307 /* 308 * We could roll this to a function, to handle it as 309 * a regular variable function callback, but why bother? 310 */ 311 if (vp == &vmpath || (vp == &vmail && ! mpathset())) 312 chkmail(1); 313 INTON; 314 return; 315 } 316 } 317 /* not found */ 318 if (flags & VNOSET) 319 return; 320 vp = ckmalloc(sizeof (*vp)); 321 vp->flags = flags & ~VNOFUNC; 322 vp->text = s; 323 vp->next = *vpp; 324 vp->func = NULL; 325 *vpp = vp; 326 } 327 328 329 330 /* 331 * Process a linked list of variable assignments. 332 */ 333 334 void 335 listsetvar(struct strlist *list, int flags) 336 { 337 struct strlist *lp; 338 339 INTOFF; 340 for (lp = list ; lp ; lp = lp->next) { 341 setvareq(savestr(lp->text), flags); 342 } 343 INTON; 344 } 345 346 void 347 listmklocal(struct strlist *list, int flags) 348 { 349 struct strlist *lp; 350 351 for (lp = list ; lp ; lp = lp->next) 352 mklocal(lp->text, flags); 353 } 354 355 356 /* 357 * Find the value of a variable. Returns NULL if not set. 358 */ 359 360 char * 361 lookupvar(const char *name) 362 { 363 struct var *v; 364 365 for (v = *hashvar(name) ; v ; v = v->next) { 366 if (varequal(v->text, name)) { 367 if (v->flags & VUNSET) 368 return NULL; 369 return strchr(v->text, '=') + 1; 370 } 371 } 372 return NULL; 373 } 374 375 376 377 /* 378 * Search the environment of a builtin command. If the second argument 379 * is nonzero, return the value of a variable even if it hasn't been 380 * exported. 381 */ 382 383 char * 384 bltinlookup(const char *name, int doall) 385 { 386 struct strlist *sp; 387 struct var *v; 388 389 for (sp = cmdenviron ; sp ; sp = sp->next) { 390 if (varequal(sp->text, name)) 391 return strchr(sp->text, '=') + 1; 392 } 393 for (v = *hashvar(name) ; v ; v = v->next) { 394 if (varequal(v->text, name)) { 395 if ((v->flags & VUNSET) 396 || (!doall && (v->flags & VEXPORT) == 0)) 397 return NULL; 398 return strchr(v->text, '=') + 1; 399 } 400 } 401 return NULL; 402 } 403 404 405 406 /* 407 * Generate a list of exported variables. This routine is used to construct 408 * the third argument to execve when executing a program. 409 */ 410 411 char ** 412 environment(void) 413 { 414 int nenv; 415 struct var **vpp; 416 struct var *vp; 417 char **env; 418 char **ep; 419 420 nenv = 0; 421 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 422 for (vp = *vpp ; vp ; vp = vp->next) 423 if (vp->flags & VEXPORT) 424 nenv++; 425 } 426 ep = env = stalloc((nenv + 1) * sizeof *env); 427 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 428 for (vp = *vpp ; vp ; vp = vp->next) 429 if (vp->flags & VEXPORT) 430 *ep++ = vp->text; 431 } 432 *ep = NULL; 433 return env; 434 } 435 436 437 /* 438 * Called when a shell procedure is invoked to clear out nonexported 439 * variables. It is also necessary to reallocate variables of with 440 * VSTACK set since these are currently allocated on the stack. 441 */ 442 443 #ifdef mkinit 444 void shprocvar(void); 445 446 SHELLPROC { 447 shprocvar(); 448 } 449 #endif 450 451 void 452 shprocvar(void) 453 { 454 struct var **vpp; 455 struct var *vp, **prev; 456 457 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 458 for (prev = vpp ; (vp = *prev) != NULL ; ) { 459 if ((vp->flags & VEXPORT) == 0) { 460 *prev = vp->next; 461 if ((vp->flags & VTEXTFIXED) == 0) 462 ckfree(vp->text); 463 if ((vp->flags & VSTRFIXED) == 0) 464 ckfree(vp); 465 } else { 466 if (vp->flags & VSTACK) { 467 vp->text = savestr(vp->text); 468 vp->flags &=~ VSTACK; 469 } 470 prev = &vp->next; 471 } 472 } 473 } 474 initvar(); 475 } 476 477 478 479 /* 480 * Command to list all variables which are set. Currently this command 481 * is invoked from the set command when the set command is called without 482 * any variables. 483 */ 484 485 void 486 print_quoted(const char *p) 487 { 488 const char *q; 489 490 if (strcspn(p, "|&;<>()$`\\\"' \t\n*?[]#~=%") == strlen(p)) { 491 out1fmt("%s", p); 492 return; 493 } 494 while (*p) { 495 if (*p == '\'') { 496 out1fmt("\\'"); 497 p++; 498 continue; 499 } 500 q = index(p, '\''); 501 if (!q) { 502 out1fmt("'%s'", p ); 503 return; 504 } 505 out1fmt("'%.*s'", (int)(q - p), p ); 506 p = q; 507 } 508 } 509 510 static int 511 sort_var(const void *v_v1, const void *v_v2) 512 { 513 const struct var * const *v1 = v_v1; 514 const struct var * const *v2 = v_v2; 515 516 /* XXX Will anyone notice we include the '=' of the shorter name? */ 517 return strcoll((*v1)->text, (*v2)->text); 518 } 519 520 /* 521 * POSIX requires that 'set' (but not export or readonly) output the 522 * variables in lexicographic order - by the locale's collating order (sigh). 523 * Maybe we could keep them in an ordered balanced binary tree 524 * instead of hashed lists. 525 * For now just roll 'em through qsort for printing... 526 */ 527 528 int 529 showvars(const char *name, int flag, int show_value) 530 { 531 struct var **vpp; 532 struct var *vp; 533 const char *p; 534 535 static struct var **list; /* static in case we are interrupted */ 536 static int list_len; 537 int count = 0; 538 539 if (!list) { 540 list_len = 32; 541 list = ckmalloc(list_len * sizeof *list); 542 } 543 544 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 545 for (vp = *vpp ; vp ; vp = vp->next) { 546 if (flag && !(vp->flags & flag)) 547 continue; 548 if (vp->flags & VUNSET && !(show_value & 2)) 549 continue; 550 if (count >= list_len) { 551 list = ckrealloc(list, 552 (list_len << 1) * sizeof *list); 553 list_len <<= 1; 554 } 555 list[count++] = vp; 556 } 557 } 558 559 qsort(list, count, sizeof *list, sort_var); 560 561 for (vpp = list; count--; vpp++) { 562 vp = *vpp; 563 if (name) 564 out1fmt("%s ", name); 565 for (p = vp->text ; *p != '=' ; p++) 566 out1c(*p); 567 if (!(vp->flags & VUNSET) && show_value) { 568 out1fmt("="); 569 print_quoted(++p); 570 } 571 out1c('\n'); 572 } 573 return 0; 574 } 575 576 577 578 /* 579 * The export and readonly commands. 580 */ 581 582 int 583 exportcmd(int argc, char **argv) 584 { 585 struct var **vpp; 586 struct var *vp; 587 char *name; 588 const char *p; 589 int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT; 590 int pflag; 591 592 pflag = nextopt("p") == 'p' ? 3 : 0; 593 if (argc <= 1 || pflag) { 594 showvars( pflag ? argv[0] : 0, flag, pflag ); 595 return 0; 596 } 597 598 while ((name = *argptr++) != NULL) { 599 if ((p = strchr(name, '=')) != NULL) { 600 p++; 601 } else { 602 vpp = hashvar(name); 603 for (vp = *vpp ; vp ; vp = vp->next) { 604 if (varequal(vp->text, name)) { 605 vp->flags |= flag; 606 goto found; 607 } 608 } 609 } 610 setvar(name, p, flag); 611 found:; 612 } 613 return 0; 614 } 615 616 617 /* 618 * The "local" command. 619 */ 620 621 int 622 localcmd(int argc, char **argv) 623 { 624 char *name; 625 626 if (! in_function()) 627 error("Not in a function"); 628 while ((name = *argptr++) != NULL) { 629 mklocal(name, 0); 630 } 631 return 0; 632 } 633 634 635 /* 636 * Make a variable a local variable. When a variable is made local, it's 637 * value and flags are saved in a localvar structure. The saved values 638 * will be restored when the shell function returns. We handle the name 639 * "-" as a special case. 640 */ 641 642 void 643 mklocal(const char *name, int flags) 644 { 645 struct localvar *lvp; 646 struct var **vpp; 647 struct var *vp; 648 649 INTOFF; 650 lvp = ckmalloc(sizeof (struct localvar)); 651 if (name[0] == '-' && name[1] == '\0') { 652 char *p; 653 p = ckmalloc(sizeof_optlist); 654 lvp->text = memcpy(p, optlist, sizeof_optlist); 655 vp = NULL; 656 } else { 657 vpp = hashvar(name); 658 for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next); 659 if (vp == NULL) { 660 if (strchr(name, '=')) 661 setvareq(savestr(name), VSTRFIXED|flags); 662 else 663 setvar(name, NULL, VSTRFIXED|flags); 664 vp = *vpp; /* the new variable */ 665 lvp->text = NULL; 666 lvp->flags = VUNSET; 667 } else { 668 lvp->text = vp->text; 669 lvp->flags = vp->flags; 670 vp->flags |= VSTRFIXED|VTEXTFIXED; 671 if (strchr(name, '=')) 672 setvareq(savestr(name), flags); 673 } 674 } 675 lvp->vp = vp; 676 lvp->next = localvars; 677 localvars = lvp; 678 INTON; 679 } 680 681 682 /* 683 * Called after a function returns. 684 */ 685 686 void 687 poplocalvars(void) 688 { 689 struct localvar *lvp; 690 struct var *vp; 691 692 while ((lvp = localvars) != NULL) { 693 localvars = lvp->next; 694 vp = lvp->vp; 695 TRACE(("poplocalvar %s", vp ? vp->text : "-")); 696 if (vp == NULL) { /* $- saved */ 697 memcpy(optlist, lvp->text, sizeof_optlist); 698 ckfree(lvp->text); 699 } else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) { 700 (void)unsetvar(vp->text, 0); 701 } else { 702 if (vp->func && (vp->flags & VNOFUNC) == 0) 703 (*vp->func)(strchr(lvp->text, '=') + 1); 704 if ((vp->flags & VTEXTFIXED) == 0) 705 ckfree(vp->text); 706 vp->flags = lvp->flags; 707 vp->text = lvp->text; 708 } 709 ckfree(lvp); 710 } 711 } 712 713 714 int 715 setvarcmd(int argc, char **argv) 716 { 717 if (argc <= 2) 718 return unsetcmd(argc, argv); 719 else if (argc == 3) 720 setvar(argv[1], argv[2], 0); 721 else 722 error("List assignment not implemented"); 723 return 0; 724 } 725 726 727 /* 728 * The unset builtin command. We unset the function before we unset the 729 * variable to allow a function to be unset when there is a readonly variable 730 * with the same name. 731 */ 732 733 int 734 unsetcmd(int argc, char **argv) 735 { 736 char **ap; 737 int i; 738 int flg_func = 0; 739 int flg_var = 0; 740 int ret = 0; 741 742 while ((i = nextopt("evf")) != '\0') { 743 if (i == 'f') 744 flg_func = 1; 745 else 746 flg_var = i; 747 } 748 if (flg_func == 0 && flg_var == 0) 749 flg_var = 1; 750 751 for (ap = argptr; *ap ; ap++) { 752 if (flg_func) 753 ret |= unsetfunc(*ap); 754 if (flg_var) 755 ret |= unsetvar(*ap, flg_var == 'e'); 756 } 757 return ret; 758 } 759 760 761 /* 762 * Unset the specified variable. 763 */ 764 765 int 766 unsetvar(const char *s, int unexport) 767 { 768 struct var **vpp; 769 struct var *vp; 770 771 vpp = hashvar(s); 772 for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) { 773 if (varequal(vp->text, s)) { 774 if (vp->flags & VREADONLY) 775 return (1); 776 INTOFF; 777 if (unexport) { 778 vp->flags &= ~VEXPORT; 779 } else { 780 if (*(strchr(vp->text, '=') + 1) != '\0') 781 setvar(s, nullstr, 0); 782 vp->flags &= ~VEXPORT; 783 vp->flags |= VUNSET; 784 if ((vp->flags & VSTRFIXED) == 0) { 785 if ((vp->flags & VTEXTFIXED) == 0) 786 ckfree(vp->text); 787 *vpp = vp->next; 788 ckfree(vp); 789 } 790 } 791 INTON; 792 return (0); 793 } 794 } 795 796 return (1); 797 } 798 799 800 801 /* 802 * Find the appropriate entry in the hash table from the name. 803 */ 804 805 STATIC struct var ** 806 hashvar(const char *p) 807 { 808 unsigned int hashval; 809 810 hashval = ((unsigned char) *p) << 4; 811 while (*p && *p != '=') 812 hashval += (unsigned char) *p++; 813 return &vartab[hashval % VTABSIZE]; 814 } 815 816 817 818 /* 819 * Returns true if the two strings specify the same varable. The first 820 * variable name is terminated by '='; the second may be terminated by 821 * either '=' or '\0'. 822 */ 823 824 STATIC int 825 varequal(const char *p, const char *q) 826 { 827 while (*p == *q++) { 828 if (*p++ == '=') 829 return 1; 830 } 831 if (*p == '=' && *(q - 1) == '\0') 832 return 1; 833 return 0; 834 } 835