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 * $Id$ 37 */ 38 39 #ifndef lint 40 static char sccsid[] = "@(#)var.c 8.1 (Berkeley) 5/31/93"; 41 #endif /* not lint */ 42 43 /* 44 * Shell variables. 45 */ 46 47 #include "shell.h" 48 #include "output.h" 49 #include "expand.h" 50 #include "nodes.h" /* for other headers */ 51 #include "eval.h" /* defines cmdenviron */ 52 #include "exec.h" 53 #include "syntax.h" 54 #include "options.h" 55 #include "mail.h" 56 #include "var.h" 57 #include "memalloc.h" 58 #include "error.h" 59 #include "mystring.h" 60 61 62 #define VTABSIZE 39 63 64 65 struct varinit { 66 struct var *var; 67 int flags; 68 char *text; 69 }; 70 71 72 #if ATTY 73 struct var vatty; 74 #endif 75 struct var vhistsize; 76 struct var vifs; 77 struct var vmail; 78 struct var vmpath; 79 struct var vpath; 80 struct var vps1; 81 struct var vps2; 82 struct var vvers; 83 #if ATTY 84 struct var vterm; 85 #endif 86 87 const struct varinit varinit[] = { 88 #if ATTY 89 {&vatty, VSTRFIXED|VTEXTFIXED|VUNSET, "ATTY="}, 90 #endif 91 {&vhistsize, VSTRFIXED|VTEXTFIXED|VUNSET, "HISTSIZE="}, 92 {&vifs, VSTRFIXED|VTEXTFIXED, "IFS= \t\n"}, 93 {&vmail, VSTRFIXED|VTEXTFIXED|VUNSET, "MAIL="}, 94 {&vmpath, VSTRFIXED|VTEXTFIXED|VUNSET, "MAILPATH="}, 95 {&vpath, VSTRFIXED|VTEXTFIXED, "PATH=:/bin:/usr/bin"}, 96 /* 97 * vps1 depends on uid 98 */ 99 {&vps2, VSTRFIXED|VTEXTFIXED, "PS2=> "}, 100 #if ATTY 101 {&vterm, VSTRFIXED|VTEXTFIXED|VUNSET, "TERM="}, 102 #endif 103 {NULL, 0, NULL} 104 }; 105 106 struct var *vartab[VTABSIZE]; 107 108 STATIC int unsetvar __P((char *)); 109 STATIC struct var **hashvar __P((char *)); 110 STATIC int varequal __P((char *, char *)); 111 112 /* 113 * Initialize the varable symbol tables and import the environment 114 */ 115 116 #ifdef mkinit 117 INCLUDE "var.h" 118 INIT { 119 char **envp; 120 extern char **environ; 121 122 initvar(); 123 for (envp = environ ; *envp ; envp++) { 124 if (strchr(*envp, '=')) { 125 setvareq(*envp, VEXPORT|VTEXTFIXED); 126 } 127 } 128 } 129 #endif 130 131 132 /* 133 * This routine initializes the builtin variables. It is called when the 134 * shell is initialized and again when a shell procedure is spawned. 135 */ 136 137 void 138 initvar() { 139 const struct varinit *ip; 140 struct var *vp; 141 struct var **vpp; 142 143 for (ip = varinit ; (vp = ip->var) != NULL ; ip++) { 144 if ((vp->flags & VEXPORT) == 0) { 145 vpp = hashvar(ip->text); 146 vp->next = *vpp; 147 *vpp = vp; 148 vp->text = ip->text; 149 vp->flags = ip->flags; 150 } 151 } 152 /* 153 * PS1 depends on uid 154 */ 155 if ((vps1.flags & VEXPORT) == 0) { 156 vpp = hashvar("PS1="); 157 vps1.next = *vpp; 158 *vpp = &vps1; 159 vps1.text = geteuid() ? "PS1=$ " : "PS1=# "; 160 vps1.flags = VSTRFIXED|VTEXTFIXED; 161 } 162 } 163 164 /* 165 * Set the value of a variable. The flags argument is ored with the 166 * flags of the variable. If val is NULL, the variable is unset. 167 */ 168 169 void 170 setvar(name, val, flags) 171 char *name, *val; 172 { 173 char *p, *q; 174 int len; 175 int namelen; 176 char *nameeq; 177 int isbad; 178 179 isbad = 0; 180 p = name; 181 if (! is_name(*p++)) 182 isbad = 1; 183 for (;;) { 184 if (! is_in_name(*p)) { 185 if (*p == '\0' || *p == '=') 186 break; 187 isbad = 1; 188 } 189 p++; 190 } 191 namelen = p - name; 192 if (isbad) 193 error("%.*s: bad variable name", namelen, name); 194 len = namelen + 2; /* 2 is space for '=' and '\0' */ 195 if (val == NULL) { 196 flags |= VUNSET; 197 } else { 198 len += strlen(val); 199 } 200 p = nameeq = ckmalloc(len); 201 q = name; 202 while (--namelen >= 0) 203 *p++ = *q++; 204 *p++ = '='; 205 *p = '\0'; 206 if (val) 207 scopy(val, p); 208 setvareq(nameeq, flags); 209 } 210 211 212 213 /* 214 * Same as setvar except that the variable and value are passed in 215 * the first argument as name=value. Since the first argument will 216 * be actually stored in the table, it should not be a string that 217 * will go away. 218 */ 219 220 void 221 setvareq(s, flags) 222 char *s; 223 { 224 struct var *vp, **vpp; 225 226 vpp = hashvar(s); 227 for (vp = *vpp ; vp ; vp = vp->next) { 228 if (varequal(s, vp->text)) { 229 if (vp->flags & VREADONLY) { 230 int len = strchr(s, '=') - s; 231 error("%.*s: is read only", len, s); 232 } 233 INTOFF; 234 if (vp == &vpath) 235 changepath(s + 5); /* 5 = strlen("PATH=") */ 236 if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0) 237 ckfree(vp->text); 238 vp->flags &=~ (VTEXTFIXED|VSTACK|VUNSET); 239 vp->flags |= flags; 240 vp->text = s; 241 if (vp == &vmpath || (vp == &vmail && ! mpathset())) 242 chkmail(1); 243 if (vp == &vhistsize) 244 sethistsize(); 245 INTON; 246 return; 247 } 248 } 249 /* not found */ 250 vp = ckmalloc(sizeof (*vp)); 251 vp->flags = flags; 252 vp->text = s; 253 vp->next = *vpp; 254 *vpp = vp; 255 } 256 257 258 259 /* 260 * Process a linked list of variable assignments. 261 */ 262 263 void 264 listsetvar(list) 265 struct strlist *list; 266 { 267 struct strlist *lp; 268 269 INTOFF; 270 for (lp = list ; lp ; lp = lp->next) { 271 setvareq(savestr(lp->text), 0); 272 } 273 INTON; 274 } 275 276 277 278 /* 279 * Find the value of a variable. Returns NULL if not set. 280 */ 281 282 char * 283 lookupvar(name) 284 char *name; 285 { 286 struct var *v; 287 288 for (v = *hashvar(name) ; v ; v = v->next) { 289 if (varequal(v->text, name)) { 290 if (v->flags & VUNSET) 291 return NULL; 292 return strchr(v->text, '=') + 1; 293 } 294 } 295 return NULL; 296 } 297 298 299 300 /* 301 * Search the environment of a builtin command. If the second argument 302 * is nonzero, return the value of a variable even if it hasn't been 303 * exported. 304 */ 305 306 char * 307 bltinlookup(name, doall) 308 char *name; 309 { 310 struct strlist *sp; 311 struct var *v; 312 313 for (sp = cmdenviron ; sp ; sp = sp->next) { 314 if (varequal(sp->text, name)) 315 return strchr(sp->text, '=') + 1; 316 } 317 for (v = *hashvar(name) ; v ; v = v->next) { 318 if (varequal(v->text, name)) { 319 if (v->flags & VUNSET 320 || ! doall && (v->flags & VEXPORT) == 0) 321 return NULL; 322 return strchr(v->text, '=') + 1; 323 } 324 } 325 return NULL; 326 } 327 328 329 330 /* 331 * Generate a list of exported variables. This routine is used to construct 332 * the third argument to execve when executing a program. 333 */ 334 335 char ** 336 environment() { 337 int nenv; 338 struct var **vpp; 339 struct var *vp; 340 char **env, **ep; 341 342 nenv = 0; 343 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 344 for (vp = *vpp ; vp ; vp = vp->next) 345 if (vp->flags & VEXPORT) 346 nenv++; 347 } 348 ep = env = stalloc((nenv + 1) * sizeof *env); 349 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 350 for (vp = *vpp ; vp ; vp = vp->next) 351 if (vp->flags & VEXPORT) 352 *ep++ = vp->text; 353 } 354 *ep = NULL; 355 return env; 356 } 357 358 359 /* 360 * Called when a shell procedure is invoked to clear out nonexported 361 * variables. It is also necessary to reallocate variables of with 362 * VSTACK set since these are currently allocated on the stack. 363 */ 364 365 #ifdef mkinit 366 MKINIT void shprocvar(); 367 368 SHELLPROC { 369 shprocvar(); 370 } 371 #endif 372 373 void 374 shprocvar() { 375 struct var **vpp; 376 struct var *vp, **prev; 377 378 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 379 for (prev = vpp ; (vp = *prev) != NULL ; ) { 380 if ((vp->flags & VEXPORT) == 0) { 381 *prev = vp->next; 382 if ((vp->flags & VTEXTFIXED) == 0) 383 ckfree(vp->text); 384 if ((vp->flags & VSTRFIXED) == 0) 385 ckfree(vp); 386 } else { 387 if (vp->flags & VSTACK) { 388 vp->text = savestr(vp->text); 389 vp->flags &=~ VSTACK; 390 } 391 prev = &vp->next; 392 } 393 } 394 } 395 initvar(); 396 } 397 398 399 400 /* 401 * Command to list all variables which are set. Currently this command 402 * is invoked from the set command when the set command is called without 403 * any variables. 404 */ 405 406 int 407 showvarscmd(argc, argv) char **argv; { 408 struct var **vpp; 409 struct var *vp; 410 411 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 412 for (vp = *vpp ; vp ; vp = vp->next) { 413 if ((vp->flags & VUNSET) == 0) 414 out1fmt("%s\n", vp->text); 415 } 416 } 417 return 0; 418 } 419 420 421 422 /* 423 * The export and readonly commands. 424 */ 425 426 int 427 exportcmd(argc, argv) char **argv; { 428 struct var **vpp; 429 struct var *vp; 430 char *name; 431 char *p; 432 int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT; 433 434 listsetvar(cmdenviron); 435 if (argc > 1) { 436 while ((name = *argptr++) != NULL) { 437 if ((p = strchr(name, '=')) != NULL) { 438 p++; 439 } else { 440 vpp = hashvar(name); 441 for (vp = *vpp ; vp ; vp = vp->next) { 442 if (varequal(vp->text, name)) { 443 vp->flags |= flag; 444 goto found; 445 } 446 } 447 } 448 setvar(name, p, flag); 449 found:; 450 } 451 } else { 452 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { 453 for (vp = *vpp ; vp ; vp = vp->next) { 454 if (vp->flags & flag) { 455 for (p = vp->text ; *p != '=' ; p++) 456 out1c(*p); 457 out1c('\n'); 458 } 459 } 460 } 461 } 462 return 0; 463 } 464 465 466 /* 467 * The "local" command. 468 */ 469 470 localcmd(argc, argv) char **argv; { 471 char *name; 472 473 if (! in_function()) 474 error("Not in a function"); 475 while ((name = *argptr++) != NULL) { 476 mklocal(name); 477 } 478 return 0; 479 } 480 481 482 /* 483 * Make a variable a local variable. When a variable is made local, it's 484 * value and flags are saved in a localvar structure. The saved values 485 * will be restored when the shell function returns. We handle the name 486 * "-" as a special case. 487 */ 488 489 void 490 mklocal(name) 491 char *name; 492 { 493 struct localvar *lvp; 494 struct var **vpp; 495 struct var *vp; 496 497 INTOFF; 498 lvp = ckmalloc(sizeof (struct localvar)); 499 if (name[0] == '-' && name[1] == '\0') { 500 lvp->text = ckmalloc(sizeof optlist); 501 bcopy(optlist, lvp->text, sizeof optlist); 502 vp = NULL; 503 } else { 504 vpp = hashvar(name); 505 for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next); 506 if (vp == NULL) { 507 if (strchr(name, '=')) 508 setvareq(savestr(name), VSTRFIXED); 509 else 510 setvar(name, NULL, VSTRFIXED); 511 vp = *vpp; /* the new variable */ 512 lvp->text = NULL; 513 lvp->flags = VUNSET; 514 } else { 515 lvp->text = vp->text; 516 lvp->flags = vp->flags; 517 vp->flags |= VSTRFIXED|VTEXTFIXED; 518 if (strchr(name, '=')) 519 setvareq(savestr(name), 0); 520 } 521 } 522 lvp->vp = vp; 523 lvp->next = localvars; 524 localvars = lvp; 525 INTON; 526 } 527 528 529 /* 530 * Called after a function returns. 531 */ 532 533 void 534 poplocalvars() { 535 struct localvar *lvp; 536 struct var *vp; 537 538 while ((lvp = localvars) != NULL) { 539 localvars = lvp->next; 540 vp = lvp->vp; 541 if (vp == NULL) { /* $- saved */ 542 bcopy(lvp->text, optlist, sizeof optlist); 543 ckfree(lvp->text); 544 } else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) { 545 (void)unsetvar(vp->text); 546 } else { 547 if ((vp->flags & VTEXTFIXED) == 0) 548 ckfree(vp->text); 549 vp->flags = lvp->flags; 550 vp->text = lvp->text; 551 } 552 ckfree(lvp); 553 } 554 } 555 556 557 setvarcmd(argc, argv) char **argv; { 558 if (argc <= 2) 559 return unsetcmd(argc, argv); 560 else if (argc == 3) 561 setvar(argv[1], argv[2], 0); 562 else 563 error("List assignment not implemented"); 564 return 0; 565 } 566 567 568 /* 569 * The unset builtin command. We unset the function before we unset the 570 * variable to allow a function to be unset when there is a readonly variable 571 * with the same name. 572 */ 573 574 unsetcmd(argc, argv) char **argv; { 575 char **ap; 576 int i; 577 int flg_func = 0; 578 int flg_var = 0; 579 int ret = 0; 580 581 while ((i = nextopt("vf")) != '\0') { 582 if (i == 'f') 583 flg_func = 1; 584 else 585 flg_var = 1; 586 } 587 if (flg_func == 0 && flg_var == 0) 588 flg_var = 1; 589 590 for (ap = argptr; *ap ; ap++) { 591 if (flg_func) 592 ret |= unsetfunc(*ap); 593 if (flg_var) 594 ret |= unsetvar(*ap); 595 } 596 return ret; 597 } 598 599 600 /* 601 * Unset the specified variable. 602 */ 603 604 STATIC int 605 unsetvar(s) 606 char *s; 607 { 608 struct var **vpp; 609 struct var *vp; 610 611 vpp = hashvar(s); 612 for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) { 613 if (varequal(vp->text, s)) { 614 if (vp->flags & VREADONLY) 615 return (1); 616 INTOFF; 617 if (*(strchr(vp->text, '=') + 1) != '\0') 618 setvar(s, nullstr, 0); 619 vp->flags &=~ VEXPORT; 620 vp->flags |= VUNSET; 621 if ((vp->flags & VSTRFIXED) == 0) { 622 if ((vp->flags & VTEXTFIXED) == 0) 623 ckfree(vp->text); 624 *vpp = vp->next; 625 ckfree(vp); 626 } 627 INTON; 628 return (0); 629 } 630 } 631 632 return (1); 633 } 634 635 636 637 /* 638 * Find the appropriate entry in the hash table from the name. 639 */ 640 641 STATIC struct var ** 642 hashvar(p) 643 register char *p; 644 { 645 unsigned int hashval; 646 647 hashval = *p << 4; 648 while (*p && *p != '=') 649 hashval += *p++; 650 return &vartab[hashval % VTABSIZE]; 651 } 652 653 654 655 /* 656 * Returns true if the two strings specify the same varable. The first 657 * variable name is terminated by '='; the second may be terminated by 658 * either '=' or '\0'. 659 */ 660 661 STATIC int 662 varequal(p, q) 663 register char *p, *q; 664 { 665 while (*p == *q++) { 666 if (*p++ == '=') 667 return 1; 668 } 669 if (*p == '=' && *(q - 1) == '\0') 670 return 1; 671 return 0; 672 } 673