var.c revision 199660
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 199660 2009-11-22 18:23:30Z jilles $"); 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 *const savehandler = handler; 197 int err = 0; 198 int inton; 199 200 inton = is_int_on(); 201 if (setjmp(jmploc.loc)) 202 err = 1; 203 else { 204 handler = &jmploc; 205 setvar(name, val, flags); 206 } 207 handler = savehandler; 208 SETINTON(inton); 209 return err; 210} 211 212/* 213 * Set the value of a variable. The flags argument is stored with the 214 * flags of the variable. If val is NULL, the variable is unset. 215 */ 216 217void 218setvar(char *name, char *val, int flags) 219{ 220 char *p, *q; 221 int len; 222 int namelen; 223 char *nameeq; 224 int isbad; 225 226 isbad = 0; 227 p = name; 228 if (! is_name(*p)) 229 isbad = 1; 230 p++; 231 for (;;) { 232 if (! is_in_name(*p)) { 233 if (*p == '\0' || *p == '=') 234 break; 235 isbad = 1; 236 } 237 p++; 238 } 239 namelen = p - name; 240 if (isbad) 241 error("%.*s: bad variable name", namelen, name); 242 len = namelen + 2; /* 2 is space for '=' and '\0' */ 243 if (val == NULL) { 244 flags |= VUNSET; 245 } else { 246 len += strlen(val); 247 } 248 p = nameeq = ckmalloc(len); 249 q = name; 250 while (--namelen >= 0) 251 *p++ = *q++; 252 *p++ = '='; 253 *p = '\0'; 254 if (val) 255 scopy(val, p); 256 setvareq(nameeq, flags); 257} 258 259STATIC int 260localevar(char *s) 261{ 262 static char *lnames[7] = { 263 "ALL", "COLLATE", "CTYPE", "MONETARY", 264 "NUMERIC", "TIME", NULL 265 }; 266 char **ss; 267 268 if (*s != 'L') 269 return 0; 270 if (varequal(s + 1, "ANG")) 271 return 1; 272 if (strncmp(s + 1, "C_", 2) != 0) 273 return 0; 274 for (ss = lnames; *ss ; ss++) 275 if (varequal(s + 3, *ss)) 276 return 1; 277 return 0; 278} 279 280 281/* 282 * Sets/unsets an environment variable from a pointer that may actually be a 283 * pointer into environ where the string should not be manipulated. 284 */ 285static void 286change_env(char *s, int set) 287{ 288 char *eqp; 289 char *ss; 290 291 ss = savestr(s); 292 if ((eqp = strchr(ss, '=')) != NULL) 293 *eqp = '\0'; 294 if (set && eqp != NULL) 295 (void) setenv(ss, eqp + 1, 1); 296 else 297 (void) unsetenv(ss); 298 ckfree(ss); 299 300 return; 301} 302 303 304/* 305 * Same as setvar except that the variable and value are passed in 306 * the first argument as name=value. Since the first argument will 307 * be actually stored in the table, it should not be a string that 308 * will go away. 309 */ 310 311void 312setvareq(char *s, int flags) 313{ 314 struct var *vp, **vpp; 315 int len; 316 317 if (aflag) 318 flags |= VEXPORT; 319 vpp = hashvar(s); 320 for (vp = *vpp ; vp ; vp = vp->next) { 321 if (varequal(s, vp->text)) { 322 if (vp->flags & VREADONLY) { 323 len = strchr(s, '=') - s; 324 error("%.*s: is read only", len, s); 325 } 326 INTOFF; 327 328 if (vp->func && (flags & VNOFUNC) == 0) 329 (*vp->func)(strchr(s, '=') + 1); 330 331 if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0) 332 ckfree(vp->text); 333 334 vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET); 335 vp->flags |= flags; 336 vp->text = s; 337 338 /* 339 * We could roll this to a function, to handle it as 340 * a regular variable function callback, but why bother? 341 */ 342 if (vp == &vmpath || (vp == &vmail && ! mpathset())) 343 chkmail(1); 344 if ((vp->flags & VEXPORT) && localevar(s)) { 345 change_env(s, 1); 346 (void) setlocale(LC_ALL, ""); 347 } 348 INTON; 349 return; 350 } 351 } 352 /* not found */ 353 vp = ckmalloc(sizeof (*vp)); 354 vp->flags = flags; 355 vp->text = s; 356 vp->next = *vpp; 357 vp->func = NULL; 358 INTOFF; 359 *vpp = vp; 360 if ((vp->flags & VEXPORT) && localevar(s)) { 361 change_env(s, 1); 362 (void) setlocale(LC_ALL, ""); 363 } 364 INTON; 365} 366 367 368 369/* 370 * Process a linked list of variable assignments. 371 */ 372 373void 374listsetvar(struct strlist *list) 375{ 376 struct strlist *lp; 377 378 INTOFF; 379 for (lp = list ; lp ; lp = lp->next) { 380 setvareq(savestr(lp->text), 0); 381 } 382 INTON; 383} 384 385 386 387/* 388 * Find the value of a variable. Returns NULL if not set. 389 */ 390 391char * 392lookupvar(char *name) 393{ 394 struct var *v; 395 396 for (v = *hashvar(name) ; v ; v = v->next) { 397 if (varequal(v->text, name)) { 398 if (v->flags & VUNSET) 399 return NULL; 400 return strchr(v->text, '=') + 1; 401 } 402 } 403 return NULL; 404} 405 406 407 408/* 409 * Search the environment of a builtin command. If the second argument 410 * is nonzero, return the value of a variable even if it hasn't been 411 * exported. 412 */ 413 414char * 415bltinlookup(char *name, int doall) 416{ 417 struct strlist *sp; 418 struct var *v; 419 420 for (sp = cmdenviron ; sp ; sp = sp->next) { 421 if (varequal(sp->text, name)) 422 return strchr(sp->text, '=') + 1; 423 } 424 for (v = *hashvar(name) ; v ; v = v->next) { 425 if (varequal(v->text, name)) { 426 if ((v->flags & VUNSET) 427 || (!doall && (v->flags & VEXPORT) == 0)) 428 return NULL; 429 return strchr(v->text, '=') + 1; 430 } 431 } 432 return NULL; 433} 434 435 436 437/* 438 * Generate a list of exported variables. This routine is used to construct 439 * the third argument to execve when executing a program. 440 */ 441 442char ** 443environment(void) 444{ 445 int nenv; 446 struct var **vpp; 447 struct var *vp; 448 char **env, **ep; 449 450 nenv = 0; 451 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 452 for (vp = *vpp ; vp ; vp = vp->next) 453 if (vp->flags & VEXPORT) 454 nenv++; 455 } 456 ep = env = stalloc((nenv + 1) * sizeof *env); 457 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 458 for (vp = *vpp ; vp ; vp = vp->next) 459 if (vp->flags & VEXPORT) 460 *ep++ = vp->text; 461 } 462 *ep = NULL; 463 return env; 464} 465 466 467/* 468 * Called when a shell procedure is invoked to clear out nonexported 469 * variables. It is also necessary to reallocate variables of with 470 * VSTACK set since these are currently allocated on the stack. 471 */ 472 473#ifdef mkinit 474MKINIT void shprocvar(void); 475 476SHELLPROC { 477 shprocvar(); 478} 479#endif 480 481void 482shprocvar(void) 483{ 484 struct var **vpp; 485 struct var *vp, **prev; 486 487 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 488 for (prev = vpp ; (vp = *prev) != NULL ; ) { 489 if ((vp->flags & VEXPORT) == 0) { 490 *prev = vp->next; 491 if ((vp->flags & VTEXTFIXED) == 0) 492 ckfree(vp->text); 493 if ((vp->flags & VSTRFIXED) == 0) 494 ckfree(vp); 495 } else { 496 if (vp->flags & VSTACK) { 497 vp->text = savestr(vp->text); 498 vp->flags &=~ VSTACK; 499 } 500 prev = &vp->next; 501 } 502 } 503 } 504 initvar(); 505} 506 507 508static int 509var_compare(const void *a, const void *b) 510{ 511 const char *const *sa, *const *sb; 512 513 sa = a; 514 sb = b; 515 /* 516 * This compares two var=value strings which creates a different 517 * order from what you would probably expect. POSIX is somewhat 518 * ambiguous on what should be sorted exactly. 519 */ 520 return strcoll(*sa, *sb); 521} 522 523 524/* 525 * Command to list all variables which are set. Currently this command 526 * is invoked from the set command when the set command is called without 527 * any variables. 528 */ 529 530int 531showvarscmd(int argc __unused, char **argv __unused) 532{ 533 struct var **vpp; 534 struct var *vp; 535 const char *s; 536 const char **vars; 537 int i, n; 538 539 /* 540 * POSIX requires us to sort the variables. 541 */ 542 n = 0; 543 for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) { 544 for (vp = *vpp; vp; vp = vp->next) { 545 if (!(vp->flags & VUNSET)) 546 n++; 547 } 548 } 549 550 INTON; 551 vars = ckmalloc(n * sizeof(*vars)); 552 i = 0; 553 for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) { 554 for (vp = *vpp; vp; vp = vp->next) { 555 if (!(vp->flags & VUNSET)) 556 vars[i++] = vp->text; 557 } 558 } 559 560 qsort(vars, n, sizeof(*vars), var_compare); 561 for (i = 0; i < n; i++) { 562 for (s = vars[i]; *s != '='; s++) 563 out1c(*s); 564 out1c('='); 565 out1qstr(s + 1); 566 out1c('\n'); 567 } 568 ckfree(vars); 569 INTOFF; 570 571 return 0; 572} 573 574 575 576/* 577 * The export and readonly commands. 578 */ 579 580int 581exportcmd(int argc, char **argv) 582{ 583 struct var **vpp; 584 struct var *vp; 585 char *name; 586 char *p; 587 char *cmdname; 588 int ch, values; 589 int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT; 590 591 cmdname = argv[0]; 592 optreset = optind = 1; 593 opterr = 0; 594 values = 0; 595 while ((ch = getopt(argc, argv, "p")) != -1) { 596 switch (ch) { 597 case 'p': 598 values = 1; 599 break; 600 case '?': 601 default: 602 error("unknown option: -%c", optopt); 603 } 604 } 605 argc -= optind; 606 argv += optind; 607 608 if (values && argc != 0) 609 error("-p requires no arguments"); 610 listsetvar(cmdenviron); 611 if (argc != 0) { 612 while ((name = *argv++) != NULL) { 613 if ((p = strchr(name, '=')) != NULL) { 614 p++; 615 } else { 616 vpp = hashvar(name); 617 for (vp = *vpp ; vp ; vp = vp->next) { 618 if (varequal(vp->text, name)) { 619 620 vp->flags |= flag; 621 if ((vp->flags & VEXPORT) && localevar(vp->text)) { 622 change_env(vp->text, 1); 623 (void) setlocale(LC_ALL, ""); 624 } 625 goto found; 626 } 627 } 628 } 629 setvar(name, p, flag); 630found:; 631 } 632 } else { 633 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 634 for (vp = *vpp ; vp ; vp = vp->next) { 635 if (vp->flags & flag) { 636 if (values) { 637 out1str(cmdname); 638 out1c(' '); 639 } 640 for (p = vp->text ; *p != '=' ; p++) 641 out1c(*p); 642 if (values && !(vp->flags & VUNSET)) { 643 out1c('='); 644 out1qstr(p + 1); 645 } 646 out1c('\n'); 647 } 648 } 649 } 650 } 651 return 0; 652} 653 654 655/* 656 * The "local" command. 657 */ 658 659int 660localcmd(int argc __unused, char **argv __unused) 661{ 662 char *name; 663 664 if (! in_function()) 665 error("Not in a function"); 666 while ((name = *argptr++) != NULL) { 667 mklocal(name); 668 } 669 return 0; 670} 671 672 673/* 674 * Make a variable a local variable. When a variable is made local, it's 675 * value and flags are saved in a localvar structure. The saved values 676 * will be restored when the shell function returns. We handle the name 677 * "-" as a special case. 678 */ 679 680void 681mklocal(char *name) 682{ 683 struct localvar *lvp; 684 struct var **vpp; 685 struct var *vp; 686 687 INTOFF; 688 lvp = ckmalloc(sizeof (struct localvar)); 689 if (name[0] == '-' && name[1] == '\0') { 690 lvp->text = ckmalloc(sizeof optlist); 691 memcpy(lvp->text, optlist, sizeof optlist); 692 vp = NULL; 693 } else { 694 vpp = hashvar(name); 695 for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next); 696 if (vp == NULL) { 697 if (strchr(name, '=')) 698 setvareq(savestr(name), VSTRFIXED); 699 else 700 setvar(name, NULL, VSTRFIXED); 701 vp = *vpp; /* the new variable */ 702 lvp->text = NULL; 703 lvp->flags = VUNSET; 704 } else { 705 lvp->text = vp->text; 706 lvp->flags = vp->flags; 707 vp->flags |= VSTRFIXED|VTEXTFIXED; 708 if (strchr(name, '=')) 709 setvareq(savestr(name), 0); 710 } 711 } 712 lvp->vp = vp; 713 lvp->next = localvars; 714 localvars = lvp; 715 INTON; 716} 717 718 719/* 720 * Called after a function returns. 721 */ 722 723void 724poplocalvars(void) 725{ 726 struct localvar *lvp; 727 struct var *vp; 728 729 while ((lvp = localvars) != NULL) { 730 localvars = lvp->next; 731 vp = lvp->vp; 732 if (vp == NULL) { /* $- saved */ 733 memcpy(optlist, lvp->text, sizeof optlist); 734 ckfree(lvp->text); 735 } else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) { 736 (void)unsetvar(vp->text); 737 } else { 738 if ((vp->flags & VTEXTFIXED) == 0) 739 ckfree(vp->text); 740 vp->flags = lvp->flags; 741 vp->text = lvp->text; 742 } 743 ckfree(lvp); 744 } 745} 746 747 748int 749setvarcmd(int argc, char **argv) 750{ 751 if (argc <= 2) 752 return unsetcmd(argc, argv); 753 else if (argc == 3) 754 setvar(argv[1], argv[2], 0); 755 else 756 error("List assignment not implemented"); 757 return 0; 758} 759 760 761/* 762 * The unset builtin command. We unset the function before we unset the 763 * variable to allow a function to be unset when there is a readonly variable 764 * with the same name. 765 */ 766 767int 768unsetcmd(int argc __unused, char **argv __unused) 769{ 770 char **ap; 771 int i; 772 int flg_func = 0; 773 int flg_var = 0; 774 int ret = 0; 775 776 while ((i = nextopt("vf")) != '\0') { 777 if (i == 'f') 778 flg_func = 1; 779 else 780 flg_var = 1; 781 } 782 if (flg_func == 0 && flg_var == 0) 783 flg_var = 1; 784 785 for (ap = argptr; *ap ; ap++) { 786 if (flg_func) 787 ret |= unsetfunc(*ap); 788 if (flg_var) 789 ret |= unsetvar(*ap); 790 } 791 return ret; 792} 793 794 795/* 796 * Unset the specified variable. 797 */ 798 799int 800unsetvar(char *s) 801{ 802 struct var **vpp; 803 struct var *vp; 804 805 vpp = hashvar(s); 806 for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) { 807 if (varequal(vp->text, s)) { 808 if (vp->flags & VREADONLY) 809 return (1); 810 INTOFF; 811 if (*(strchr(vp->text, '=') + 1) != '\0') 812 setvar(s, nullstr, 0); 813 if ((vp->flags & VEXPORT) && localevar(vp->text)) { 814 change_env(s, 0); 815 setlocale(LC_ALL, ""); 816 } 817 vp->flags &= ~VEXPORT; 818 vp->flags |= VUNSET; 819 if ((vp->flags & VSTRFIXED) == 0) { 820 if ((vp->flags & VTEXTFIXED) == 0) 821 ckfree(vp->text); 822 *vpp = vp->next; 823 ckfree(vp); 824 } 825 INTON; 826 return (0); 827 } 828 } 829 830 return (0); 831} 832 833 834 835/* 836 * Find the appropriate entry in the hash table from the name. 837 */ 838 839STATIC struct var ** 840hashvar(char *p) 841{ 842 unsigned int hashval; 843 844 hashval = ((unsigned char) *p) << 4; 845 while (*p && *p != '=') 846 hashval += (unsigned char) *p++; 847 return &vartab[hashval % VTABSIZE]; 848} 849 850 851 852/* 853 * Returns true if the two strings specify the same varable. The first 854 * variable name is terminated by '='; the second may be terminated by 855 * either '=' or '\0'. 856 */ 857 858STATIC int 859varequal(char *p, char *q) 860{ 861 while (*p == *q++) { 862 if (*p++ == '=') 863 return 1; 864 } 865 if (*p == '=' && *(q - 1) == '\0') 866 return 1; 867 return 0; 868} 869