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 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)var.c 8.3 (Berkeley) 5/4/95 37 * $FreeBSD: src/bin/sh/var.c,v 1.62 2011/06/13 21:03:27 jilles Exp $ 38 */ 39 40 #include <unistd.h> 41 #include <stdlib.h> 42 43 /* 44 * Shell variables. 45 */ 46 47 #include <locale.h> 48 #include <langinfo.h> 49 #include <paths.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 #include "builtins.h" 66 #ifndef NO_HISTORY 67 #include "myhistedit.h" 68 #endif 69 70 71 #define VTABSIZE 39 72 73 74 struct varinit { 75 struct var *var; 76 int flags; 77 const char *text; 78 void (*func)(const char *); 79 }; 80 81 82 #ifndef NO_HISTORY 83 struct var vhistsize; 84 struct var vterm; 85 #endif 86 struct var vifs; 87 struct var vmail; 88 struct var vmpath; 89 struct var vpath; 90 struct var vppid; 91 struct var vps1; 92 struct var vps2; 93 struct var vps4; 94 struct var vvers; 95 static struct var voptind; 96 97 int forcelocal; 98 99 static const struct varinit varinit[] = { 100 #ifndef NO_HISTORY 101 { &vhistsize, VUNSET, "HISTSIZE=", 102 sethistsize }, 103 #endif 104 { &vifs, 0, "IFS= \t\n", 105 NULL }, 106 { &vmail, VUNSET, "MAIL=", 107 NULL }, 108 { &vmpath, VUNSET, "MAILPATH=", 109 NULL }, 110 { &vpath, 0, "PATH=" _PATH_DEFPATH, 111 changepath }, 112 { &vppid, VUNSET, "PPID=", 113 NULL }, 114 /* 115 * vps1 depends on uid 116 */ 117 { &vps2, 0, "PS2=> ", 118 NULL }, 119 { &vps4, 0, "PS4=+ ", 120 NULL }, 121 #ifndef NO_HISTORY 122 { &vterm, VUNSET, "TERM=", 123 setterm }, 124 #endif 125 { &voptind, 0, "OPTIND=1", 126 getoptsreset }, 127 { NULL, 0, NULL, 128 NULL } 129 }; 130 131 static struct var *vartab[VTABSIZE]; 132 133 static const char *const locale_names[7] = { 134 "LC_COLLATE", "LC_CTYPE", "LC_MONETARY", 135 "LC_NUMERIC", "LC_TIME", "LC_MESSAGES", NULL 136 }; 137 static const int locale_categories[7] = { 138 LC_COLLATE, LC_CTYPE, LC_MONETARY, LC_NUMERIC, LC_TIME, LC_MESSAGES, 0 139 }; 140 141 static int varequal(const char *, const char *); 142 static struct var *find_var(const char *, struct var ***, int *); 143 static int localevar(const char *); 144 145 /* 146 * Initialize the variable symbol tables and import the environment. 147 */ 148 149 #ifdef mkinit 150 INCLUDE "var.h" 151 MKINIT char **environ; 152 INIT { 153 char **envp; 154 155 initvar(); 156 for (envp = environ ; *envp ; envp++) { 157 if (strchr(*envp, '=')) { 158 setvareq(*envp, VEXPORT|VTEXTFIXED); 159 } 160 } 161 } 162 #endif 163 164 165 /* 166 * This routine initializes the builtin variables. It is called when the 167 * shell is initialized. 168 */ 169 170 void 171 initvar(void) 172 { 173 char ppid[20]; 174 const struct varinit *ip; 175 struct var *vp; 176 struct var **vpp; 177 178 for (ip = varinit ; (vp = ip->var) != NULL ; ip++) { 179 if (find_var(ip->text, &vpp, &vp->name_len) != NULL) 180 continue; 181 vp->next = *vpp; 182 *vpp = vp; 183 vp->text = __DECONST(char *, ip->text); 184 vp->flags = ip->flags | VSTRFIXED | VTEXTFIXED; 185 vp->func = ip->func; 186 } 187 /* 188 * PS1 depends on uid 189 */ 190 if (find_var("PS1", &vpp, &vps1.name_len) == NULL) { 191 vps1.next = *vpp; 192 *vpp = &vps1; 193 vps1.text = __DECONST(char *, geteuid() ? "PS1=$ " : "PS1=# "); 194 vps1.flags = VSTRFIXED|VTEXTFIXED; 195 } 196 if ((vppid.flags & VEXPORT) == 0) { 197 fmtstr(ppid, sizeof(ppid), "%d", (int)getppid()); 198 setvarsafe("PPID", ppid, 0); 199 } 200 } 201 202 /* 203 * Safe version of setvar, returns 1 on success 0 on failure. 204 */ 205 206 int 207 setvarsafe(const char *name, const char *val, int flags) 208 { 209 struct jmploc jmploc; 210 struct jmploc *const savehandler = handler; 211 int err = 0; 212 int inton; 213 214 inton = is_int_on(); 215 if (setjmp(jmploc.loc)) 216 err = 1; 217 else { 218 handler = &jmploc; 219 setvar(name, val, flags); 220 } 221 handler = savehandler; 222 SETINTON(inton); 223 return err; 224 } 225 226 /* 227 * Set the value of a variable. The flags argument is stored with the 228 * flags of the variable. If val is NULL, the variable is unset. 229 */ 230 231 void 232 setvar(const char *name, const char *val, int flags) 233 { 234 const char *p; 235 int len; 236 int namelen; 237 char *nameeq; 238 int isbad; 239 240 isbad = 0; 241 p = name; 242 if (!is_name(*p)) 243 isbad = 1; 244 p++; 245 for (;;) { 246 if (!is_in_name(*p)) { 247 if (*p == '\0' || *p == '=') 248 break; 249 isbad = 1; 250 } 251 p++; 252 } 253 namelen = p - name; 254 if (isbad) 255 error("%.*s: bad variable name", namelen, name); 256 len = namelen + 2; /* 2 is space for '=' and '\0' */ 257 if (val == NULL) { 258 flags |= VUNSET; 259 } else { 260 len += strlen(val); 261 } 262 nameeq = ckmalloc(len); 263 memcpy(nameeq, name, namelen); 264 nameeq[namelen] = '='; 265 if (val) 266 scopy(val, nameeq + namelen + 1); 267 else 268 nameeq[namelen + 1] = '\0'; 269 setvareq(nameeq, flags); 270 } 271 272 static int 273 localevar(const char *s) 274 { 275 const char *const *ss; 276 277 if (*s != 'L') 278 return 0; 279 if (varequal(s + 1, "ANG")) 280 return 1; 281 if (strncmp(s + 1, "C_", 2) != 0) 282 return 0; 283 if (varequal(s + 3, "ALL")) 284 return 1; 285 for (ss = locale_names; *ss ; ss++) 286 if (varequal(s + 3, *ss + 3)) 287 return 1; 288 return 0; 289 } 290 291 /* 292 * Sets/unsets an environment variable from a pointer that may actually be a 293 * pointer into environ where the string should not be manipulated. 294 */ 295 static void 296 change_env(const char *s, int set) 297 { 298 char *eqp; 299 char *ss; 300 301 ss = savestr(s); 302 if ((eqp = strchr(ss, '=')) != NULL) 303 *eqp = '\0'; 304 if (set && eqp != NULL) { 305 if (setenv(ss, eqp + 1, 1) != 0) 306 error("setenv: cannot set %s=%s", ss, eqp + 1); 307 } else 308 unsetenv(ss); 309 ckfree(ss); 310 } 311 312 313 /* 314 * Same as setvar except that the variable and value are passed in 315 * the first argument as name=value. Since the first argument will 316 * be actually stored in the table, it should not be a string that 317 * will go away. 318 */ 319 320 void 321 setvareq(char *s, int flags) 322 { 323 struct var *vp, **vpp; 324 int nlen; 325 326 if (aflag) 327 flags |= VEXPORT; 328 if (forcelocal && !(flags & (VNOSET | VNOLOCAL))) 329 mklocal(s); 330 vp = find_var(s, &vpp, &nlen); 331 if (vp != NULL) { 332 if (vp->flags & VREADONLY) 333 error("%.*s: is read only", vp->name_len, s); 334 if (flags & VNOSET) 335 return; 336 INTOFF; 337 338 if (vp->func && (flags & VNOFUNC) == 0) 339 (*vp->func)(s + vp->name_len + 1); 340 341 if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0) 342 ckfree(vp->text); 343 344 vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET); 345 vp->flags |= flags; 346 vp->text = s; 347 348 /* 349 * We could roll this to a function, to handle it as 350 * a regular variable function callback, but why bother? 351 * 352 * Note: this assumes iflag is not set to 1 initially. 353 * As part of init(), this is called before arguments 354 * are looked at. 355 */ 356 if ((vp == &vmpath || (vp == &vmail && ! mpathset())) && 357 iflag == 1) 358 chkmail(1); 359 if ((vp->flags & VEXPORT) && localevar(s)) { 360 change_env(s, 1); 361 setlocale(LC_ALL, ""); 362 updatecharset(); 363 } 364 INTON; 365 return; 366 } 367 /* not found */ 368 if (flags & VNOSET) 369 return; 370 vp = ckmalloc(sizeof (*vp)); 371 vp->flags = flags; 372 vp->text = s; 373 vp->name_len = nlen; 374 vp->next = *vpp; 375 vp->func = NULL; 376 INTOFF; 377 *vpp = vp; 378 if ((vp->flags & VEXPORT) && localevar(s)) { 379 change_env(s, 1); 380 setlocale(LC_ALL, ""); 381 updatecharset(); 382 } 383 INTON; 384 } 385 386 387 388 /* 389 * Process a linked list of variable assignments. 390 */ 391 392 void 393 listsetvar(struct strlist *list, int flags) 394 { 395 struct strlist *lp; 396 397 INTOFF; 398 for (lp = list ; lp ; lp = lp->next) { 399 setvareq(savestr(lp->text), flags); 400 } 401 INTON; 402 } 403 404 405 406 /* 407 * Find the value of a variable. Returns NULL if not set. 408 */ 409 410 char * 411 lookupvar(const char *name) 412 { 413 struct var *v; 414 415 v = find_var(name, NULL, NULL); 416 if (v == NULL || v->flags & VUNSET) 417 return NULL; 418 return v->text + v->name_len + 1; 419 } 420 421 422 423 /* 424 * Search the environment of a builtin command. If the second argument 425 * is nonzero, return the value of a variable even if it hasn't been 426 * exported. 427 */ 428 429 char * 430 bltinlookup(const char *name, int doall) 431 { 432 struct strlist *sp; 433 struct var *v; 434 char *result; 435 436 result = NULL; 437 for (sp = cmdenviron ; sp ; sp = sp->next) { 438 if (varequal(sp->text, name)) 439 result = strchr(sp->text, '=') + 1; 440 } 441 if (result != NULL) 442 return result; 443 444 v = find_var(name, NULL, NULL); 445 if (v == NULL || v->flags & VUNSET || 446 (!doall && (v->flags & VEXPORT) == 0)) 447 return NULL; 448 return v->text + v->name_len + 1; 449 } 450 451 452 /* 453 * Set up locale for a builtin (LANG/LC_* assignments). 454 */ 455 void 456 bltinsetlocale(void) 457 { 458 struct strlist *lp; 459 int act = 0; 460 char *loc, *locdef; 461 int i; 462 463 for (lp = cmdenviron ; lp ; lp = lp->next) { 464 if (localevar(lp->text)) { 465 act = 1; 466 break; 467 } 468 } 469 if (!act) 470 return; 471 loc = bltinlookup("LC_ALL", 0); 472 INTOFF; 473 if (loc != NULL) { 474 setlocale(LC_ALL, loc); 475 INTON; 476 updatecharset(); 477 return; 478 } 479 locdef = bltinlookup("LANG", 0); 480 for (i = 0; locale_names[i] != NULL; i++) { 481 loc = bltinlookup(locale_names[i], 0); 482 if (loc == NULL) 483 loc = locdef; 484 if (loc != NULL) 485 setlocale(locale_categories[i], loc); 486 } 487 INTON; 488 updatecharset(); 489 } 490 491 /* 492 * Undo the effect of bltinlocaleset(). 493 */ 494 void 495 bltinunsetlocale(void) 496 { 497 struct strlist *lp; 498 499 INTOFF; 500 for (lp = cmdenviron ; lp ; lp = lp->next) { 501 if (localevar(lp->text)) { 502 setlocale(LC_ALL, ""); 503 updatecharset(); 504 return; 505 } 506 } 507 INTON; 508 } 509 510 /* 511 * Update the localeisutf8 flag. 512 */ 513 void 514 updatecharset(void) 515 { 516 char *charset; 517 518 charset = nl_langinfo(CODESET); 519 localeisutf8 = !strcmp(charset, "UTF-8"); 520 } 521 522 void 523 initcharset(void) 524 { 525 updatecharset(); 526 initial_localeisutf8 = localeisutf8; 527 } 528 529 /* 530 * Generate a list of exported variables. This routine is used to construct 531 * the third argument to execve when executing a program. 532 */ 533 534 char ** 535 environment(void) 536 { 537 int nenv; 538 struct var **vpp; 539 struct var *vp; 540 char **env, **ep; 541 542 nenv = 0; 543 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 544 for (vp = *vpp ; vp ; vp = vp->next) 545 if (vp->flags & VEXPORT) 546 nenv++; 547 } 548 ep = env = stalloc((nenv + 1) * sizeof *env); 549 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 550 for (vp = *vpp ; vp ; vp = vp->next) 551 if (vp->flags & VEXPORT) 552 *ep++ = vp->text; 553 } 554 *ep = NULL; 555 return env; 556 } 557 558 559 static int 560 var_compare(const void *a, const void *b) 561 { 562 const char *const *sa, *const *sb; 563 564 sa = a; 565 sb = b; 566 /* 567 * This compares two var=value strings which creates a different 568 * order from what you would probably expect. POSIX is somewhat 569 * ambiguous on what should be sorted exactly. 570 */ 571 return strcoll(*sa, *sb); 572 } 573 574 575 /* 576 * Command to list all variables which are set. This is invoked from the 577 * set command when it is called without any options or operands. 578 */ 579 580 int 581 showvarscmd(int argc __unused, char **argv __unused) 582 { 583 struct var **vpp; 584 struct var *vp; 585 const char *s; 586 const char **vars; 587 int i, n; 588 589 /* 590 * POSIX requires us to sort the variables. 591 */ 592 n = 0; 593 for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) { 594 for (vp = *vpp; vp; vp = vp->next) { 595 if (!(vp->flags & VUNSET)) 596 n++; 597 } 598 } 599 600 INTON; 601 vars = ckmalloc(n * sizeof(*vars)); 602 i = 0; 603 for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) { 604 for (vp = *vpp; vp; vp = vp->next) { 605 if (!(vp->flags & VUNSET)) 606 vars[i++] = vp->text; 607 } 608 } 609 610 qsort(vars, n, sizeof(*vars), var_compare); 611 for (i = 0; i < n; i++) { 612 s = strchr(vars[i], '='); 613 s++; 614 outbin(vars[i], s - vars[i], out1); 615 out1qstr(s); 616 out1c('\n'); 617 } 618 ckfree(vars); 619 INTOFF; 620 621 return 0; 622 } 623 624 625 626 /* 627 * The export and readonly commands. 628 */ 629 630 int 631 exportcmd(int argc, char **argv) 632 { 633 struct var **vpp; 634 struct var *vp; 635 char *name; 636 char *p; 637 char *cmdname; 638 int ch, values; 639 int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT; 640 641 cmdname = argv[0]; 642 optreset = optind = 1; 643 opterr = 0; 644 values = 0; 645 while ((ch = getopt(argc, argv, "p")) != -1) { 646 switch (ch) { 647 case 'p': 648 values = 1; 649 break; 650 case '?': 651 default: 652 error("unknown option: -%c", optopt); 653 } 654 } 655 argc -= optind; 656 argv += optind; 657 658 if (values && argc != 0) 659 error("-p requires no arguments"); 660 if (argc != 0) { 661 while ((name = *argv++) != NULL) { 662 if ((p = strchr(name, '=')) != NULL) { 663 p++; 664 } else { 665 vp = find_var(name, NULL, NULL); 666 if (vp != NULL) { 667 vp->flags |= flag; 668 if ((vp->flags & VEXPORT) && localevar(vp->text)) { 669 change_env(vp->text, 1); 670 setlocale(LC_ALL, ""); 671 updatecharset(); 672 } 673 continue; 674 } 675 } 676 setvar(name, p, flag); 677 } 678 } else { 679 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 680 for (vp = *vpp ; vp ; vp = vp->next) { 681 if (vp->flags & flag) { 682 if (values) { 683 out1str(cmdname); 684 out1c(' '); 685 } 686 if (values && !(vp->flags & VUNSET)) { 687 outbin(vp->text, 688 vp->name_len + 1, out1); 689 out1qstr(vp->text + 690 vp->name_len + 1); 691 } else 692 outbin(vp->text, vp->name_len, 693 out1); 694 out1c('\n'); 695 } 696 } 697 } 698 } 699 return 0; 700 } 701 702 703 /* 704 * The "local" command. 705 */ 706 707 int 708 localcmd(int argc __unused, char **argv __unused) 709 { 710 char *name; 711 712 if (! in_function()) 713 error("Not in a function"); 714 while ((name = *argptr++) != NULL) { 715 mklocal(name); 716 } 717 return 0; 718 } 719 720 721 /* 722 * Make a variable a local variable. When a variable is made local, it's 723 * value and flags are saved in a localvar structure. The saved values 724 * will be restored when the shell function returns. We handle the name 725 * "-" as a special case. 726 */ 727 728 void 729 mklocal(char *name) 730 { 731 struct localvar *lvp; 732 struct var **vpp; 733 struct var *vp; 734 735 INTOFF; 736 lvp = ckmalloc(sizeof (struct localvar)); 737 if (name[0] == '-' && name[1] == '\0') { 738 lvp->text = ckmalloc(sizeof optlist); 739 memcpy(lvp->text, optlist, sizeof optlist); 740 vp = NULL; 741 } else { 742 vp = find_var(name, &vpp, NULL); 743 if (vp == NULL) { 744 if (strchr(name, '=')) 745 setvareq(savestr(name), VSTRFIXED | VNOLOCAL); 746 else 747 setvar(name, NULL, VSTRFIXED | VNOLOCAL); 748 vp = *vpp; /* the new variable */ 749 lvp->text = NULL; 750 lvp->flags = VUNSET; 751 } else { 752 lvp->text = vp->text; 753 lvp->flags = vp->flags; 754 vp->flags |= VSTRFIXED|VTEXTFIXED; 755 if (name[vp->name_len] == '=') 756 setvareq(savestr(name), VNOLOCAL); 757 } 758 } 759 lvp->vp = vp; 760 lvp->next = localvars; 761 localvars = lvp; 762 INTON; 763 } 764 765 766 /* 767 * Called after a function returns. 768 */ 769 770 void 771 poplocalvars(void) 772 { 773 struct localvar *lvp; 774 struct var *vp; 775 776 while ((lvp = localvars) != NULL) { 777 localvars = lvp->next; 778 vp = lvp->vp; 779 if (vp == NULL) { /* $- saved */ 780 memcpy(optlist, lvp->text, sizeof optlist); 781 ckfree(lvp->text); 782 optschanged(); 783 } else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) { 784 unsetvar(vp->text); 785 } else { 786 if ((vp->flags & VTEXTFIXED) == 0) 787 ckfree(vp->text); 788 vp->flags = lvp->flags; 789 vp->text = lvp->text; 790 } 791 ckfree(lvp); 792 } 793 } 794 795 796 int 797 setvarcmd(int argc, char **argv) 798 { 799 if (argc <= 2) 800 return unsetcmd(argc, argv); 801 else if (argc == 3) 802 setvar(argv[1], argv[2], 0); 803 else 804 error("too many arguments"); 805 return 0; 806 } 807 808 809 /* 810 * The unset builtin command. 811 */ 812 813 int 814 unsetcmd(int argc __unused, char **argv __unused) 815 { 816 char **ap; 817 int i; 818 int flg_func = 0; 819 int flg_var = 0; 820 int ret = 0; 821 822 while ((i = nextopt("vf")) != '\0') { 823 if (i == 'f') 824 flg_func = 1; 825 else 826 flg_var = 1; 827 } 828 if (flg_func == 0 && flg_var == 0) 829 flg_var = 1; 830 831 for (ap = argptr; *ap ; ap++) { 832 if (flg_func) 833 ret |= unsetfunc(*ap); 834 if (flg_var) 835 ret |= unsetvar(*ap); 836 } 837 return ret; 838 } 839 840 841 /* 842 * Unset the specified variable. 843 */ 844 845 int 846 unsetvar(const char *s) 847 { 848 struct var **vpp; 849 struct var *vp; 850 851 vp = find_var(s, &vpp, NULL); 852 if (vp == NULL) 853 return (0); 854 if (vp->flags & VREADONLY) 855 return (1); 856 INTOFF; 857 if (vp->text[vp->name_len + 1] != '\0') 858 setvar(s, nullstr, 0); 859 if ((vp->flags & VEXPORT) && localevar(vp->text)) { 860 change_env(__DECONST(char *, s), 0); 861 setlocale(LC_ALL, ""); 862 updatecharset(); 863 } 864 vp->flags &= ~VEXPORT; 865 vp->flags |= VUNSET; 866 if ((vp->flags & VSTRFIXED) == 0) { 867 if ((vp->flags & VTEXTFIXED) == 0) 868 ckfree(vp->text); 869 *vpp = vp->next; 870 ckfree(vp); 871 } 872 INTON; 873 return (0); 874 } 875 876 877 878 /* 879 * Returns true if the two strings specify the same variable. The first 880 * variable name is terminated by '='; the second may be terminated by 881 * either '=' or '\0'. 882 */ 883 884 static int 885 varequal(const char *p, const char *q) 886 { 887 while (*p == *q++) { 888 if (*p++ == '=') 889 return 1; 890 } 891 if (*p == '=' && *(q - 1) == '\0') 892 return 1; 893 return 0; 894 } 895 896 /* 897 * Search for a variable. 898 * 'name' may be terminated by '=' or a NUL. 899 * vppp is set to the pointer to vp, or the list head if vp isn't found 900 * lenp is set to the number of characters in 'name' 901 */ 902 903 static struct var * 904 find_var(const char *name, struct var ***vppp, int *lenp) 905 { 906 unsigned int hashval; 907 int len; 908 struct var *vp, **vpp; 909 const char *p = name; 910 911 hashval = 0; 912 while (*p && *p != '=') 913 hashval = 2 * hashval + (unsigned char)*p++; 914 len = p - name; 915 916 if (lenp) 917 *lenp = len; 918 vpp = &vartab[hashval % VTABSIZE]; 919 if (vppp) 920 *vppp = vpp; 921 922 for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) { 923 if (vp->name_len != len) 924 continue; 925 if (memcmp(vp->text, name, len) != 0) 926 continue; 927 if (vppp) 928 *vppp = vpp; 929 return vp; 930 } 931 return NULL; 932 } 933