var.c revision 171195
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 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33#ifndef lint 34#if 0 35static char sccsid[] = "@(#)var.c 8.3 (Berkeley) 5/4/95"; 36#endif 37#endif /* not lint */ 38#include <sys/cdefs.h> 39__FBSDID("$FreeBSD: head/bin/sh/var.c 171195 2007-07-04 00:00:41Z scf $"); 40 41#include <unistd.h> 42#include <stdlib.h> 43#include <paths.h> 44 45/* 46 * Shell variables. 47 */ 48 49#include <locale.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#ifndef NO_HISTORY 66#include "myhistedit.h" 67#endif 68 69 70#define VTABSIZE 39 71 72 73struct varinit { 74 struct var *var; 75 int flags; 76 char *text; 77 void (*func)(const char *); 78}; 79 80 81#ifndef NO_HISTORY 82struct var vhistsize; 83#endif 84struct var vifs; 85struct var vmail; 86struct var vmpath; 87struct var vpath; 88struct var vppid; 89struct var vps1; 90struct var vps2; 91struct var vps4; 92struct var vvers; 93STATIC struct var voptind; 94 95STATIC const struct varinit varinit[] = { 96#ifndef NO_HISTORY 97 { &vhistsize, VSTRFIXED|VTEXTFIXED|VUNSET, "HISTSIZE=", 98 sethistsize }, 99#endif 100 { &vifs, VSTRFIXED|VTEXTFIXED, "IFS= \t\n", 101 NULL }, 102 { &vmail, VSTRFIXED|VTEXTFIXED|VUNSET, "MAIL=", 103 NULL }, 104 { &vmpath, VSTRFIXED|VTEXTFIXED|VUNSET, "MAILPATH=", 105 NULL }, 106 { &vpath, VSTRFIXED|VTEXTFIXED, "PATH=" _PATH_DEFPATH, 107 changepath }, 108 { &vppid, VSTRFIXED|VTEXTFIXED|VUNSET, "PPID=", 109 NULL }, 110 /* 111 * vps1 depends on uid 112 */ 113 { &vps2, VSTRFIXED|VTEXTFIXED, "PS2=> ", 114 NULL }, 115 { &vps4, VSTRFIXED|VTEXTFIXED, "PS4=+ ", 116 NULL }, 117 { &voptind, VSTRFIXED|VTEXTFIXED, "OPTIND=1", 118 getoptsreset }, 119 { NULL, 0, NULL, 120 NULL } 121}; 122 123STATIC struct var *vartab[VTABSIZE]; 124 125STATIC struct var **hashvar(char *); 126STATIC int varequal(char *, char *); 127STATIC int localevar(char *); 128 129/* 130 * Initialize the variable symbol tables and import the environment. 131 */ 132 133#ifdef mkinit 134INCLUDE "var.h" 135INIT { 136 char **envp; 137 extern char **environ; 138 139 initvar(); 140 for (envp = environ ; *envp ; envp++) { 141 if (strchr(*envp, '=')) { 142 setvareq(*envp, VEXPORT|VTEXTFIXED); 143 } 144 } 145} 146#endif 147 148 149/* 150 * This routine initializes the builtin variables. It is called when the 151 * shell is initialized and again when a shell procedure is spawned. 152 */ 153 154void 155initvar(void) 156{ 157 char ppid[20]; 158 const struct varinit *ip; 159 struct var *vp; 160 struct var **vpp; 161 162 for (ip = varinit ; (vp = ip->var) != NULL ; ip++) { 163 if ((vp->flags & VEXPORT) == 0) { 164 vpp = hashvar(ip->text); 165 vp->next = *vpp; 166 *vpp = vp; 167 vp->text = ip->text; 168 vp->flags = ip->flags; 169 vp->func = ip->func; 170 } 171 } 172 /* 173 * PS1 depends on uid 174 */ 175 if ((vps1.flags & VEXPORT) == 0) { 176 vpp = hashvar("PS1="); 177 vps1.next = *vpp; 178 *vpp = &vps1; 179 vps1.text = geteuid() ? "PS1=$ " : "PS1=# "; 180 vps1.flags = VSTRFIXED|VTEXTFIXED; 181 } 182 if ((vppid.flags & VEXPORT) == 0) { 183 fmtstr(ppid, sizeof(ppid), "%d", (int)getppid()); 184 setvarsafe("PPID", ppid, 0); 185 } 186} 187 188/* 189 * Safe version of setvar, returns 1 on success 0 on failure. 190 */ 191 192int 193setvarsafe(char *name, char *val, int flags) 194{ 195 struct jmploc jmploc; 196 struct jmploc *volatile savehandler = handler; 197 int err = 0; 198#if __GNUC__ 199 /* Avoid longjmp clobbering */ 200 (void) &err; 201#endif 202 203 if (setjmp(jmploc.loc)) 204 err = 1; 205 else { 206 handler = &jmploc; 207 setvar(name, val, flags); 208 } 209 handler = savehandler; 210 return err; 211} 212 213/* 214 * Set the value of a variable. The flags argument is stored with the 215 * flags of the variable. If val is NULL, the variable is unset. 216 */ 217 218void 219setvar(char *name, char *val, int flags) 220{ 221 char *p, *q; 222 int len; 223 int namelen; 224 char *nameeq; 225 int isbad; 226 227 isbad = 0; 228 p = name; 229 if (! is_name(*p)) 230 isbad = 1; 231 p++; 232 for (;;) { 233 if (! is_in_name(*p)) { 234 if (*p == '\0' || *p == '=') 235 break; 236 isbad = 1; 237 } 238 p++; 239 } 240 namelen = p - name; 241 if (isbad) 242 error("%.*s: bad variable name", namelen, name); 243 len = namelen + 2; /* 2 is space for '=' and '\0' */ 244 if (val == NULL) { 245 flags |= VUNSET; 246 } else { 247 len += strlen(val); 248 } 249 p = nameeq = ckmalloc(len); 250 q = name; 251 while (--namelen >= 0) 252 *p++ = *q++; 253 *p++ = '='; 254 *p = '\0'; 255 if (val) 256 scopy(val, p); 257 setvareq(nameeq, flags); 258} 259 260STATIC int 261localevar(char *s) 262{ 263 static char *lnames[7] = { 264 "ALL", "COLLATE", "CTYPE", "MONETARY", 265 "NUMERIC", "TIME", NULL 266 }; 267 char **ss; 268 269 if (*s != 'L') 270 return 0; 271 if (varequal(s + 1, "ANG")) 272 return 1; 273 if (strncmp(s + 1, "C_", 2) != 0) 274 return 0; 275 for (ss = lnames; *ss ; ss++) 276 if (varequal(s + 3, *ss)) 277 return 1; 278 return 0; 279} 280 281/* 282 * Same as setvar except that the variable and value are passed in 283 * the first argument as name=value. Since the first argument will 284 * be actually stored in the table, it should not be a string that 285 * will go away. 286 */ 287 288void 289setvareq(char *s, int flags) 290{ 291 struct var *vp, **vpp; 292 char *p; 293 int len; 294 295 if (aflag) 296 flags |= VEXPORT; 297 vpp = hashvar(s); 298 for (vp = *vpp ; vp ; vp = vp->next) { 299 if (varequal(s, vp->text)) { 300 if (vp->flags & VREADONLY) { 301 len = strchr(s, '=') - s; 302 error("%.*s: is read only", len, s); 303 } 304 INTOFF; 305 306 if (vp->func && (flags & VNOFUNC) == 0) 307 (*vp->func)(strchr(s, '=') + 1); 308 309 if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0) 310 ckfree(vp->text); 311 312 vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET); 313 vp->flags |= flags; 314 vp->text = s; 315 316 /* 317 * We could roll this to a function, to handle it as 318 * a regular variable function callback, but why bother? 319 */ 320 if (vp == &vmpath || (vp == &vmail && ! mpathset())) 321 chkmail(1); 322 if ((vp->flags & VEXPORT) && localevar(s)) { 323 p = strchr(s, '='); 324 *p = '\0'; 325 (void) setenv(s, p + 1, 1); 326 *p = '='; 327 (void) setlocale(LC_ALL, ""); 328 } 329 INTON; 330 return; 331 } 332 } 333 /* not found */ 334 vp = ckmalloc(sizeof (*vp)); 335 vp->flags = flags; 336 vp->text = s; 337 vp->next = *vpp; 338 vp->func = NULL; 339 INTOFF; 340 *vpp = vp; 341 if ((vp->flags & VEXPORT) && localevar(s)) { 342 p = strchr(s, '='); 343 *p = '\0'; 344 (void) setenv(s, p + 1, 1); 345 *p = '='; 346 (void) setlocale(LC_ALL, ""); 347 } 348 INTON; 349} 350 351 352 353/* 354 * Process a linked list of variable assignments. 355 */ 356 357void 358listsetvar(struct strlist *list) 359{ 360 struct strlist *lp; 361 362 INTOFF; 363 for (lp = list ; lp ; lp = lp->next) { 364 setvareq(savestr(lp->text), 0); 365 } 366 INTON; 367} 368 369 370 371/* 372 * Find the value of a variable. Returns NULL if not set. 373 */ 374 375char * 376lookupvar(char *name) 377{ 378 struct var *v; 379 380 for (v = *hashvar(name) ; v ; v = v->next) { 381 if (varequal(v->text, name)) { 382 if (v->flags & VUNSET) 383 return NULL; 384 return strchr(v->text, '=') + 1; 385 } 386 } 387 return NULL; 388} 389 390 391 392/* 393 * Search the environment of a builtin command. If the second argument 394 * is nonzero, return the value of a variable even if it hasn't been 395 * exported. 396 */ 397 398char * 399bltinlookup(char *name, int doall) 400{ 401 struct strlist *sp; 402 struct var *v; 403 404 for (sp = cmdenviron ; sp ; sp = sp->next) { 405 if (varequal(sp->text, name)) 406 return strchr(sp->text, '=') + 1; 407 } 408 for (v = *hashvar(name) ; v ; v = v->next) { 409 if (varequal(v->text, name)) { 410 if ((v->flags & VUNSET) 411 || (!doall && (v->flags & VEXPORT) == 0)) 412 return NULL; 413 return strchr(v->text, '=') + 1; 414 } 415 } 416 return NULL; 417} 418 419 420 421/* 422 * Generate a list of exported variables. This routine is used to construct 423 * the third argument to execve when executing a program. 424 */ 425 426char ** 427environment(void) 428{ 429 int nenv; 430 struct var **vpp; 431 struct var *vp; 432 char **env, **ep; 433 434 nenv = 0; 435 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 436 for (vp = *vpp ; vp ; vp = vp->next) 437 if (vp->flags & VEXPORT) 438 nenv++; 439 } 440 ep = env = stalloc((nenv + 1) * sizeof *env); 441 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 442 for (vp = *vpp ; vp ; vp = vp->next) 443 if (vp->flags & VEXPORT) 444 *ep++ = vp->text; 445 } 446 *ep = NULL; 447 return env; 448} 449 450 451/* 452 * Called when a shell procedure is invoked to clear out nonexported 453 * variables. It is also necessary to reallocate variables of with 454 * VSTACK set since these are currently allocated on the stack. 455 */ 456 457#ifdef mkinit 458MKINIT void shprocvar(void); 459 460SHELLPROC { 461 shprocvar(); 462} 463#endif 464 465void 466shprocvar(void) 467{ 468 struct var **vpp; 469 struct var *vp, **prev; 470 471 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 472 for (prev = vpp ; (vp = *prev) != NULL ; ) { 473 if ((vp->flags & VEXPORT) == 0) { 474 *prev = vp->next; 475 if ((vp->flags & VTEXTFIXED) == 0) 476 ckfree(vp->text); 477 if ((vp->flags & VSTRFIXED) == 0) 478 ckfree(vp); 479 } else { 480 if (vp->flags & VSTACK) { 481 vp->text = savestr(vp->text); 482 vp->flags &=~ VSTACK; 483 } 484 prev = &vp->next; 485 } 486 } 487 } 488 initvar(); 489} 490 491 492static int 493var_compare(const void *a, const void *b) 494{ 495 const char *const *sa, *const *sb; 496 497 sa = a; 498 sb = b; 499 /* 500 * This compares two var=value strings which creates a different 501 * order from what you would probably expect. POSIX is somewhat 502 * ambiguous on what should be sorted exactly. 503 */ 504 return strcoll(*sa, *sb); 505} 506 507 508/* 509 * Command to list all variables which are set. Currently this command 510 * is invoked from the set command when the set command is called without 511 * any variables. 512 */ 513 514int 515showvarscmd(int argc __unused, char **argv __unused) 516{ 517 struct var **vpp; 518 struct var *vp; 519 const char *s; 520 const char **vars; 521 int i, n; 522 523 /* 524 * POSIX requires us to sort the variables. 525 */ 526 n = 0; 527 for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) { 528 for (vp = *vpp; vp; vp = vp->next) { 529 if (!(vp->flags & VUNSET)) 530 n++; 531 } 532 } 533 534 INTON; 535 vars = ckmalloc(n * sizeof(*vars)); 536 i = 0; 537 for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) { 538 for (vp = *vpp; vp; vp = vp->next) { 539 if (!(vp->flags & VUNSET)) 540 vars[i++] = vp->text; 541 } 542 } 543 544 qsort(vars, n, sizeof(*vars), var_compare); 545 for (i = 0; i < n; i++) { 546 for (s = vars[i]; *s != '='; s++) 547 out1c(*s); 548 out1c('='); 549 out1qstr(s + 1); 550 out1c('\n'); 551 } 552 ckfree(vars); 553 INTOFF; 554 555 return 0; 556} 557 558 559 560/* 561 * The export and readonly commands. 562 */ 563 564int 565exportcmd(int argc, char **argv) 566{ 567 struct var **vpp; 568 struct var *vp; 569 char *name; 570 char *p; 571 char *cmdname; 572 int ch, values; 573 int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT; 574 575 cmdname = argv[0]; 576 optreset = optind = 1; 577 opterr = 0; 578 values = 0; 579 while ((ch = getopt(argc, argv, "p")) != -1) { 580 switch (ch) { 581 case 'p': 582 values = 1; 583 break; 584 case '?': 585 default: 586 error("unknown option: -%c", optopt); 587 } 588 } 589 argc -= optind; 590 argv += optind; 591 592 if (values && argc != 0) 593 error("-p requires no arguments"); 594 listsetvar(cmdenviron); 595 if (argc != 0) { 596 while ((name = *argv++) != NULL) { 597 if ((p = strchr(name, '=')) != NULL) { 598 p++; 599 } else { 600 vpp = hashvar(name); 601 for (vp = *vpp ; vp ; vp = vp->next) { 602 if (varequal(vp->text, name)) { 603 604 vp->flags |= flag; 605 if ((vp->flags & VEXPORT) && localevar(vp->text)) { 606 p = strchr(vp->text, '='); 607 *p = '\0'; 608 (void) setenv(vp->text, p + 1, 1); 609 *p = '='; 610 (void) setlocale(LC_ALL, ""); 611 } 612 goto found; 613 } 614 } 615 } 616 setvar(name, p, flag); 617found:; 618 } 619 } else { 620 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 621 for (vp = *vpp ; vp ; vp = vp->next) { 622 if (vp->flags & flag) { 623 if (values) { 624 out1str(cmdname); 625 out1c(' '); 626 } 627 for (p = vp->text ; *p != '=' ; p++) 628 out1c(*p); 629 if (values && !(vp->flags & VUNSET)) { 630 out1c('='); 631 out1qstr(p + 1); 632 } 633 out1c('\n'); 634 } 635 } 636 } 637 } 638 return 0; 639} 640 641 642/* 643 * The "local" command. 644 */ 645 646int 647localcmd(int argc __unused, char **argv __unused) 648{ 649 char *name; 650 651 if (! in_function()) 652 error("Not in a function"); 653 while ((name = *argptr++) != NULL) { 654 mklocal(name); 655 } 656 return 0; 657} 658 659 660/* 661 * Make a variable a local variable. When a variable is made local, it's 662 * value and flags are saved in a localvar structure. The saved values 663 * will be restored when the shell function returns. We handle the name 664 * "-" as a special case. 665 */ 666 667void 668mklocal(char *name) 669{ 670 struct localvar *lvp; 671 struct var **vpp; 672 struct var *vp; 673 674 INTOFF; 675 lvp = ckmalloc(sizeof (struct localvar)); 676 if (name[0] == '-' && name[1] == '\0') { 677 lvp->text = ckmalloc(sizeof optlist); 678 memcpy(lvp->text, optlist, sizeof optlist); 679 vp = NULL; 680 } else { 681 vpp = hashvar(name); 682 for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next); 683 if (vp == NULL) { 684 if (strchr(name, '=')) 685 setvareq(savestr(name), VSTRFIXED); 686 else 687 setvar(name, NULL, VSTRFIXED); 688 vp = *vpp; /* the new variable */ 689 lvp->text = NULL; 690 lvp->flags = VUNSET; 691 } else { 692 lvp->text = vp->text; 693 lvp->flags = vp->flags; 694 vp->flags |= VSTRFIXED|VTEXTFIXED; 695 if (strchr(name, '=')) 696 setvareq(savestr(name), 0); 697 } 698 } 699 lvp->vp = vp; 700 lvp->next = localvars; 701 localvars = lvp; 702 INTON; 703} 704 705 706/* 707 * Called after a function returns. 708 */ 709 710void 711poplocalvars(void) 712{ 713 struct localvar *lvp; 714 struct var *vp; 715 716 while ((lvp = localvars) != NULL) { 717 localvars = lvp->next; 718 vp = lvp->vp; 719 if (vp == NULL) { /* $- saved */ 720 memcpy(optlist, lvp->text, sizeof optlist); 721 ckfree(lvp->text); 722 } else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) { 723 (void)unsetvar(vp->text); 724 } else { 725 if ((vp->flags & VTEXTFIXED) == 0) 726 ckfree(vp->text); 727 vp->flags = lvp->flags; 728 vp->text = lvp->text; 729 } 730 ckfree(lvp); 731 } 732} 733 734 735int 736setvarcmd(int argc, char **argv) 737{ 738 if (argc <= 2) 739 return unsetcmd(argc, argv); 740 else if (argc == 3) 741 setvar(argv[1], argv[2], 0); 742 else 743 error("List assignment not implemented"); 744 return 0; 745} 746 747 748/* 749 * The unset builtin command. We unset the function before we unset the 750 * variable to allow a function to be unset when there is a readonly variable 751 * with the same name. 752 */ 753 754int 755unsetcmd(int argc __unused, char **argv __unused) 756{ 757 char **ap; 758 int i; 759 int flg_func = 0; 760 int flg_var = 0; 761 int ret = 0; 762 763 while ((i = nextopt("vf")) != '\0') { 764 if (i == 'f') 765 flg_func = 1; 766 else 767 flg_var = 1; 768 } 769 if (flg_func == 0 && flg_var == 0) 770 flg_var = 1; 771 772 for (ap = argptr; *ap ; ap++) { 773 if (flg_func) 774 ret |= unsetfunc(*ap); 775 if (flg_var) 776 ret |= unsetvar(*ap); 777 } 778 return ret; 779} 780 781 782/* 783 * Unset the specified variable. 784 */ 785 786int 787unsetvar(char *s) 788{ 789 struct var **vpp; 790 struct var *vp; 791 792 vpp = hashvar(s); 793 for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) { 794 if (varequal(vp->text, s)) { 795 if (vp->flags & VREADONLY) 796 return (1); 797 INTOFF; 798 if (*(strchr(vp->text, '=') + 1) != '\0') 799 setvar(s, nullstr, 0); 800 if ((vp->flags & VEXPORT) && localevar(vp->text)) { 801 unsetenv(s); 802 setlocale(LC_ALL, ""); 803 } 804 vp->flags &= ~VEXPORT; 805 vp->flags |= VUNSET; 806 if ((vp->flags & VSTRFIXED) == 0) { 807 if ((vp->flags & VTEXTFIXED) == 0) 808 ckfree(vp->text); 809 *vpp = vp->next; 810 ckfree(vp); 811 } 812 INTON; 813 return (0); 814 } 815 } 816 817 return (0); 818} 819 820 821 822/* 823 * Find the appropriate entry in the hash table from the name. 824 */ 825 826STATIC struct var ** 827hashvar(char *p) 828{ 829 unsigned int hashval; 830 831 hashval = ((unsigned char) *p) << 4; 832 while (*p && *p != '=') 833 hashval += (unsigned char) *p++; 834 return &vartab[hashval % VTABSIZE]; 835} 836 837 838 839/* 840 * Returns true if the two strings specify the same varable. The first 841 * variable name is terminated by '='; the second may be terminated by 842 * either '=' or '\0'. 843 */ 844 845STATIC int 846varequal(char *p, char *q) 847{ 848 while (*p == *q++) { 849 if (*p++ == '=') 850 return 1; 851 } 852 if (*p == '=' && *(q - 1) == '\0') 853 return 1; 854 return 0; 855} 856