| 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 | * %sccs.include.redist.c% |
| 9 | */ |
| 10 | |
| 11 | #ifndef lint |
| 12 | static char sccsid[] = "@(#)var.c 8.1 (Berkeley) %G%"; |
| 13 | #endif /* not lint */ |
| 14 | |
| 15 | /* |
| 16 | * Shell variables. |
| 17 | */ |
| 18 | |
| 19 | #include "shell.h" |
| 20 | #include "output.h" |
| 21 | #include "expand.h" |
| 22 | #include "nodes.h" /* for other headers */ |
| 23 | #include "eval.h" /* defines cmdenviron */ |
| 24 | #include "exec.h" |
| 25 | #include "syntax.h" |
| 26 | #include "options.h" |
| 27 | #include "mail.h" |
| 28 | #include "var.h" |
| 29 | #include "memalloc.h" |
| 30 | #include "error.h" |
| 31 | #include "mystring.h" |
| 32 | |
| 33 | |
| 34 | #define VTABSIZE 39 |
| 35 | |
| 36 | |
| 37 | struct varinit { |
| 38 | struct var *var; |
| 39 | int flags; |
| 40 | char *text; |
| 41 | }; |
| 42 | |
| 43 | |
| 44 | #if ATTY |
| 45 | struct var vatty; |
| 46 | #endif |
| 47 | struct var vhistsize; |
| 48 | struct var vifs; |
| 49 | struct var vmail; |
| 50 | struct var vmpath; |
| 51 | struct var vpath; |
| 52 | struct var vps1; |
| 53 | struct var vps2; |
| 54 | struct var vvers; |
| 55 | #if ATTY |
| 56 | struct var vterm; |
| 57 | #endif |
| 58 | |
| 59 | const struct varinit varinit[] = { |
| 60 | #if ATTY |
| 61 | {&vatty, VSTRFIXED|VTEXTFIXED|VUNSET, "ATTY="}, |
| 62 | #endif |
| 63 | {&vhistsize, VSTRFIXED|VTEXTFIXED|VUNSET, "HISTSIZE="}, |
| 64 | {&vifs, VSTRFIXED|VTEXTFIXED, "IFS= \t\n"}, |
| 65 | {&vmail, VSTRFIXED|VTEXTFIXED|VUNSET, "MAIL="}, |
| 66 | {&vmpath, VSTRFIXED|VTEXTFIXED|VUNSET, "MAILPATH="}, |
| 67 | {&vpath, VSTRFIXED|VTEXTFIXED, "PATH=:/bin:/usr/bin"}, |
| 68 | /* |
| 69 | * vps1 depends on uid |
| 70 | */ |
| 71 | {&vps2, VSTRFIXED|VTEXTFIXED, "PS2=> "}, |
| 72 | #if ATTY |
| 73 | {&vterm, VSTRFIXED|VTEXTFIXED|VUNSET, "TERM="}, |
| 74 | #endif |
| 75 | {NULL, 0, NULL} |
| 76 | }; |
| 77 | |
| 78 | struct var *vartab[VTABSIZE]; |
| 79 | |
| 80 | STATIC int unsetvar __P((char *)); |
| 81 | STATIC struct var **hashvar __P((char *)); |
| 82 | STATIC int varequal __P((char *, char *)); |
| 83 | |
| 84 | /* |
| 85 | * Initialize the varable symbol tables and import the environment |
| 86 | */ |
| 87 | |
| 88 | #ifdef mkinit |
| 89 | INCLUDE "var.h" |
| 90 | INIT { |
| 91 | char **envp; |
| 92 | extern char **environ; |
| 93 | |
| 94 | initvar(); |
| 95 | for (envp = environ ; *envp ; envp++) { |
| 96 | if (strchr(*envp, '=')) { |
| 97 | setvareq(*envp, VEXPORT|VTEXTFIXED); |
| 98 | } |
| 99 | } |
| 100 | } |
| 101 | #endif |
| 102 | |
| 103 | |
| 104 | /* |
| 105 | * This routine initializes the builtin variables. It is called when the |
| 106 | * shell is initialized and again when a shell procedure is spawned. |
| 107 | */ |
| 108 | |
| 109 | void |
| 110 | initvar() { |
| 111 | const struct varinit *ip; |
| 112 | struct var *vp; |
| 113 | struct var **vpp; |
| 114 | |
| 115 | for (ip = varinit ; (vp = ip->var) != NULL ; ip++) { |
| 116 | if ((vp->flags & VEXPORT) == 0) { |
| 117 | vpp = hashvar(ip->text); |
| 118 | vp->next = *vpp; |
| 119 | *vpp = vp; |
| 120 | vp->text = ip->text; |
| 121 | vp->flags = ip->flags; |
| 122 | } |
| 123 | } |
| 124 | /* |
| 125 | * PS1 depends on uid |
| 126 | */ |
| 127 | if ((vps1.flags & VEXPORT) == 0) { |
| 128 | vpp = hashvar("PS1="); |
| 129 | vps1.next = *vpp; |
| 130 | *vpp = &vps1; |
| 131 | vps1.text = geteuid() ? "PS1=$ " : "PS1=# "; |
| 132 | vps1.flags = VSTRFIXED|VTEXTFIXED; |
| 133 | } |
| 134 | } |
| 135 | |
| 136 | /* |
| 137 | * Set the value of a variable. The flags argument is ored with the |
| 138 | * flags of the variable. If val is NULL, the variable is unset. |
| 139 | */ |
| 140 | |
| 141 | void |
| 142 | setvar(name, val, flags) |
| 143 | char *name, *val; |
| 144 | { |
| 145 | char *p, *q; |
| 146 | int len; |
| 147 | int namelen; |
| 148 | char *nameeq; |
| 149 | int isbad; |
| 150 | |
| 151 | isbad = 0; |
| 152 | p = name; |
| 153 | if (! is_name(*p++)) |
| 154 | isbad = 1; |
| 155 | for (;;) { |
| 156 | if (! is_in_name(*p)) { |
| 157 | if (*p == '\0' || *p == '=') |
| 158 | break; |
| 159 | isbad = 1; |
| 160 | } |
| 161 | p++; |
| 162 | } |
| 163 | namelen = p - name; |
| 164 | if (isbad) |
| 165 | error("%.*s: bad variable name", namelen, name); |
| 166 | len = namelen + 2; /* 2 is space for '=' and '\0' */ |
| 167 | if (val == NULL) { |
| 168 | flags |= VUNSET; |
| 169 | } else { |
| 170 | len += strlen(val); |
| 171 | } |
| 172 | p = nameeq = ckmalloc(len); |
| 173 | q = name; |
| 174 | while (--namelen >= 0) |
| 175 | *p++ = *q++; |
| 176 | *p++ = '='; |
| 177 | *p = '\0'; |
| 178 | if (val) |
| 179 | scopy(val, p); |
| 180 | setvareq(nameeq, flags); |
| 181 | } |
| 182 | |
| 183 | |
| 184 | |
| 185 | /* |
| 186 | * Same as setvar except that the variable and value are passed in |
| 187 | * the first argument as name=value. Since the first argument will |
| 188 | * be actually stored in the table, it should not be a string that |
| 189 | * will go away. |
| 190 | */ |
| 191 | |
| 192 | void |
| 193 | setvareq(s, flags) |
| 194 | char *s; |
| 195 | { |
| 196 | struct var *vp, **vpp; |
| 197 | |
| 198 | vpp = hashvar(s); |
| 199 | for (vp = *vpp ; vp ; vp = vp->next) { |
| 200 | if (varequal(s, vp->text)) { |
| 201 | if (vp->flags & VREADONLY) { |
| 202 | int len = strchr(s, '=') - s; |
| 203 | error("%.*s: is read only", len, s); |
| 204 | } |
| 205 | INTOFF; |
| 206 | if (vp == &vpath) |
| 207 | changepath(s + 5); /* 5 = strlen("PATH=") */ |
| 208 | if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0) |
| 209 | ckfree(vp->text); |
| 210 | vp->flags &=~ (VTEXTFIXED|VSTACK|VUNSET); |
| 211 | vp->flags |= flags; |
| 212 | vp->text = s; |
| 213 | if (vp == &vmpath || (vp == &vmail && ! mpathset())) |
| 214 | chkmail(1); |
| 215 | if (vp == &vhistsize) |
| 216 | sethistsize(); |
| 217 | INTON; |
| 218 | return; |
| 219 | } |
| 220 | } |
| 221 | /* not found */ |
| 222 | vp = ckmalloc(sizeof (*vp)); |
| 223 | vp->flags = flags; |
| 224 | vp->text = s; |
| 225 | vp->next = *vpp; |
| 226 | *vpp = vp; |
| 227 | } |
| 228 | |
| 229 | |
| 230 | |
| 231 | /* |
| 232 | * Process a linked list of variable assignments. |
| 233 | */ |
| 234 | |
| 235 | void |
| 236 | listsetvar(list) |
| 237 | struct strlist *list; |
| 238 | { |
| 239 | struct strlist *lp; |
| 240 | |
| 241 | INTOFF; |
| 242 | for (lp = list ; lp ; lp = lp->next) { |
| 243 | setvareq(savestr(lp->text), 0); |
| 244 | } |
| 245 | INTON; |
| 246 | } |
| 247 | |
| 248 | |
| 249 | |
| 250 | /* |
| 251 | * Find the value of a variable. Returns NULL if not set. |
| 252 | */ |
| 253 | |
| 254 | char * |
| 255 | lookupvar(name) |
| 256 | char *name; |
| 257 | { |
| 258 | struct var *v; |
| 259 | |
| 260 | for (v = *hashvar(name) ; v ; v = v->next) { |
| 261 | if (varequal(v->text, name)) { |
| 262 | if (v->flags & VUNSET) |
| 263 | return NULL; |
| 264 | return strchr(v->text, '=') + 1; |
| 265 | } |
| 266 | } |
| 267 | return NULL; |
| 268 | } |
| 269 | |
| 270 | |
| 271 | |
| 272 | /* |
| 273 | * Search the environment of a builtin command. If the second argument |
| 274 | * is nonzero, return the value of a variable even if it hasn't been |
| 275 | * exported. |
| 276 | */ |
| 277 | |
| 278 | char * |
| 279 | bltinlookup(name, doall) |
| 280 | char *name; |
| 281 | { |
| 282 | struct strlist *sp; |
| 283 | struct var *v; |
| 284 | |
| 285 | for (sp = cmdenviron ; sp ; sp = sp->next) { |
| 286 | if (varequal(sp->text, name)) |
| 287 | return strchr(sp->text, '=') + 1; |
| 288 | } |
| 289 | for (v = *hashvar(name) ; v ; v = v->next) { |
| 290 | if (varequal(v->text, name)) { |
| 291 | if (v->flags & VUNSET |
| 292 | || ! doall && (v->flags & VEXPORT) == 0) |
| 293 | return NULL; |
| 294 | return strchr(v->text, '=') + 1; |
| 295 | } |
| 296 | } |
| 297 | return NULL; |
| 298 | } |
| 299 | |
| 300 | |
| 301 | |
| 302 | /* |
| 303 | * Generate a list of exported variables. This routine is used to construct |
| 304 | * the third argument to execve when executing a program. |
| 305 | */ |
| 306 | |
| 307 | char ** |
| 308 | environment() { |
| 309 | int nenv; |
| 310 | struct var **vpp; |
| 311 | struct var *vp; |
| 312 | char **env, **ep; |
| 313 | |
| 314 | nenv = 0; |
| 315 | for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { |
| 316 | for (vp = *vpp ; vp ; vp = vp->next) |
| 317 | if (vp->flags & VEXPORT) |
| 318 | nenv++; |
| 319 | } |
| 320 | ep = env = stalloc((nenv + 1) * sizeof *env); |
| 321 | for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { |
| 322 | for (vp = *vpp ; vp ; vp = vp->next) |
| 323 | if (vp->flags & VEXPORT) |
| 324 | *ep++ = vp->text; |
| 325 | } |
| 326 | *ep = NULL; |
| 327 | return env; |
| 328 | } |
| 329 | |
| 330 | |
| 331 | /* |
| 332 | * Called when a shell procedure is invoked to clear out nonexported |
| 333 | * variables. It is also necessary to reallocate variables of with |
| 334 | * VSTACK set since these are currently allocated on the stack. |
| 335 | */ |
| 336 | |
| 337 | #ifdef mkinit |
| 338 | MKINIT void shprocvar(); |
| 339 | |
| 340 | SHELLPROC { |
| 341 | shprocvar(); |
| 342 | } |
| 343 | #endif |
| 344 | |
| 345 | void |
| 346 | shprocvar() { |
| 347 | struct var **vpp; |
| 348 | struct var *vp, **prev; |
| 349 | |
| 350 | for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { |
| 351 | for (prev = vpp ; (vp = *prev) != NULL ; ) { |
| 352 | if ((vp->flags & VEXPORT) == 0) { |
| 353 | *prev = vp->next; |
| 354 | if ((vp->flags & VTEXTFIXED) == 0) |
| 355 | ckfree(vp->text); |
| 356 | if ((vp->flags & VSTRFIXED) == 0) |
| 357 | ckfree(vp); |
| 358 | } else { |
| 359 | if (vp->flags & VSTACK) { |
| 360 | vp->text = savestr(vp->text); |
| 361 | vp->flags &=~ VSTACK; |
| 362 | } |
| 363 | prev = &vp->next; |
| 364 | } |
| 365 | } |
| 366 | } |
| 367 | initvar(); |
| 368 | } |
| 369 | |
| 370 | |
| 371 | |
| 372 | /* |
| 373 | * Command to list all variables which are set. Currently this command |
| 374 | * is invoked from the set command when the set command is called without |
| 375 | * any variables. |
| 376 | */ |
| 377 | |
| 378 | int |
| 379 | showvarscmd(argc, argv) char **argv; { |
| 380 | struct var **vpp; |
| 381 | struct var *vp; |
| 382 | |
| 383 | for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { |
| 384 | for (vp = *vpp ; vp ; vp = vp->next) { |
| 385 | if ((vp->flags & VUNSET) == 0) |
| 386 | out1fmt("%s\n", vp->text); |
| 387 | } |
| 388 | } |
| 389 | return 0; |
| 390 | } |
| 391 | |
| 392 | |
| 393 | |
| 394 | /* |
| 395 | * The export and readonly commands. |
| 396 | */ |
| 397 | |
| 398 | int |
| 399 | exportcmd(argc, argv) char **argv; { |
| 400 | struct var **vpp; |
| 401 | struct var *vp; |
| 402 | char *name; |
| 403 | char *p; |
| 404 | int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT; |
| 405 | |
| 406 | listsetvar(cmdenviron); |
| 407 | if (argc > 1) { |
| 408 | while ((name = *argptr++) != NULL) { |
| 409 | if ((p = strchr(name, '=')) != NULL) { |
| 410 | p++; |
| 411 | } else { |
| 412 | vpp = hashvar(name); |
| 413 | for (vp = *vpp ; vp ; vp = vp->next) { |
| 414 | if (varequal(vp->text, name)) { |
| 415 | vp->flags |= flag; |
| 416 | goto found; |
| 417 | } |
| 418 | } |
| 419 | } |
| 420 | setvar(name, p, flag); |
| 421 | found:; |
| 422 | } |
| 423 | } else { |
| 424 | for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) { |
| 425 | for (vp = *vpp ; vp ; vp = vp->next) { |
| 426 | if (vp->flags & flag) { |
| 427 | for (p = vp->text ; *p != '=' ; p++) |
| 428 | out1c(*p); |
| 429 | out1c('\n'); |
| 430 | } |
| 431 | } |
| 432 | } |
| 433 | } |
| 434 | return 0; |
| 435 | } |
| 436 | |
| 437 | |
| 438 | /* |
| 439 | * The "local" command. |
| 440 | */ |
| 441 | |
| 442 | localcmd(argc, argv) char **argv; { |
| 443 | char *name; |
| 444 | |
| 445 | if (! in_function()) |
| 446 | error("Not in a function"); |
| 447 | while ((name = *argptr++) != NULL) { |
| 448 | mklocal(name); |
| 449 | } |
| 450 | return 0; |
| 451 | } |
| 452 | |
| 453 | |
| 454 | /* |
| 455 | * Make a variable a local variable. When a variable is made local, it's |
| 456 | * value and flags are saved in a localvar structure. The saved values |
| 457 | * will be restored when the shell function returns. We handle the name |
| 458 | * "-" as a special case. |
| 459 | */ |
| 460 | |
| 461 | void |
| 462 | mklocal(name) |
| 463 | char *name; |
| 464 | { |
| 465 | struct localvar *lvp; |
| 466 | struct var **vpp; |
| 467 | struct var *vp; |
| 468 | |
| 469 | INTOFF; |
| 470 | lvp = ckmalloc(sizeof (struct localvar)); |
| 471 | if (name[0] == '-' && name[1] == '\0') { |
| 472 | lvp->text = ckmalloc(sizeof optlist); |
| 473 | bcopy(optlist, lvp->text, sizeof optlist); |
| 474 | vp = NULL; |
| 475 | } else { |
| 476 | vpp = hashvar(name); |
| 477 | for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next); |
| 478 | if (vp == NULL) { |
| 479 | if (strchr(name, '=')) |
| 480 | setvareq(savestr(name), VSTRFIXED); |
| 481 | else |
| 482 | setvar(name, NULL, VSTRFIXED); |
| 483 | vp = *vpp; /* the new variable */ |
| 484 | lvp->text = NULL; |
| 485 | lvp->flags = VUNSET; |
| 486 | } else { |
| 487 | lvp->text = vp->text; |
| 488 | lvp->flags = vp->flags; |
| 489 | vp->flags |= VSTRFIXED|VTEXTFIXED; |
| 490 | if (strchr(name, '=')) |
| 491 | setvareq(savestr(name), 0); |
| 492 | } |
| 493 | } |
| 494 | lvp->vp = vp; |
| 495 | lvp->next = localvars; |
| 496 | localvars = lvp; |
| 497 | INTON; |
| 498 | } |
| 499 | |
| 500 | |
| 501 | /* |
| 502 | * Called after a function returns. |
| 503 | */ |
| 504 | |
| 505 | void |
| 506 | poplocalvars() { |
| 507 | struct localvar *lvp; |
| 508 | struct var *vp; |
| 509 | |
| 510 | while ((lvp = localvars) != NULL) { |
| 511 | localvars = lvp->next; |
| 512 | vp = lvp->vp; |
| 513 | if (vp == NULL) { /* $- saved */ |
| 514 | bcopy(lvp->text, optlist, sizeof optlist); |
| 515 | ckfree(lvp->text); |
| 516 | } else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) { |
| 517 | (void)unsetvar(vp->text); |
| 518 | } else { |
| 519 | if ((vp->flags & VTEXTFIXED) == 0) |
| 520 | ckfree(vp->text); |
| 521 | vp->flags = lvp->flags; |
| 522 | vp->text = lvp->text; |
| 523 | } |
| 524 | ckfree(lvp); |
| 525 | } |
| 526 | } |
| 527 | |
| 528 | |
| 529 | setvarcmd(argc, argv) char **argv; { |
| 530 | if (argc <= 2) |
| 531 | return unsetcmd(argc, argv); |
| 532 | else if (argc == 3) |
| 533 | setvar(argv[1], argv[2], 0); |
| 534 | else |
| 535 | error("List assignment not implemented"); |
| 536 | return 0; |
| 537 | } |
| 538 | |
| 539 | |
| 540 | /* |
| 541 | * The unset builtin command. We unset the function before we unset the |
| 542 | * variable to allow a function to be unset when there is a readonly variable |
| 543 | * with the same name. |
| 544 | */ |
| 545 | |
| 546 | unsetcmd(argc, argv) char **argv; { |
| 547 | char **ap; |
| 548 | int i; |
| 549 | int flg_func = 0; |
| 550 | int flg_var = 0; |
| 551 | int ret = 0; |
| 552 | |
| 553 | while ((i = nextopt("vf")) != '\0') { |
| 554 | if (i == 'f') |
| 555 | flg_func = 1; |
| 556 | else |
| 557 | flg_var = 1; |
| 558 | } |
| 559 | if (flg_func == 0 && flg_var == 0) |
| 560 | flg_var = 1; |
| 561 | |
| 562 | for (ap = argptr; *ap ; ap++) { |
| 563 | if (flg_func) |
| 564 | ret |= unsetfunc(*ap); |
| 565 | if (flg_var) |
| 566 | ret |= unsetvar(*ap); |
| 567 | } |
| 568 | return ret; |
| 569 | } |
| 570 | |
| 571 | |
| 572 | /* |
| 573 | * Unset the specified variable. |
| 574 | */ |
| 575 | |
| 576 | STATIC int |
| 577 | unsetvar(s) |
| 578 | char *s; |
| 579 | { |
| 580 | struct var **vpp; |
| 581 | struct var *vp; |
| 582 | |
| 583 | vpp = hashvar(s); |
| 584 | for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) { |
| 585 | if (varequal(vp->text, s)) { |
| 586 | if (vp->flags & VREADONLY) |
| 587 | return (1); |
| 588 | INTOFF; |
| 589 | if (*(strchr(vp->text, '=') + 1) != '\0') |
| 590 | setvar(s, nullstr, 0); |
| 591 | vp->flags &=~ VEXPORT; |
| 592 | vp->flags |= VUNSET; |
| 593 | if ((vp->flags & VSTRFIXED) == 0) { |
| 594 | if ((vp->flags & VTEXTFIXED) == 0) |
| 595 | ckfree(vp->text); |
| 596 | *vpp = vp->next; |
| 597 | ckfree(vp); |
| 598 | } |
| 599 | INTON; |
| 600 | return (0); |
| 601 | } |
| 602 | } |
| 603 | |
| 604 | return (1); |
| 605 | } |
| 606 | |
| 607 | |
| 608 | |
| 609 | /* |
| 610 | * Find the appropriate entry in the hash table from the name. |
| 611 | */ |
| 612 | |
| 613 | STATIC struct var ** |
| 614 | hashvar(p) |
| 615 | register char *p; |
| 616 | { |
| 617 | unsigned int hashval; |
| 618 | |
| 619 | hashval = *p << 4; |
| 620 | while (*p && *p != '=') |
| 621 | hashval += *p++; |
| 622 | return &vartab[hashval % VTABSIZE]; |
| 623 | } |
| 624 | |
| 625 | |
| 626 | |
| 627 | /* |
| 628 | * Returns true if the two strings specify the same varable. The first |
| 629 | * variable name is terminated by '='; the second may be terminated by |
| 630 | * either '=' or '\0'. |
| 631 | */ |
| 632 | |
| 633 | STATIC int |
| 634 | varequal(p, q) |
| 635 | register char *p, *q; |
| 636 | { |
| 637 | while (*p == *q++) { |
| 638 | if (*p++ == '=') |
| 639 | return 1; |
| 640 | } |
| 641 | if (*p == '=' && *(q - 1) == '\0') |
| 642 | return 1; |
| 643 | return 0; |
| 644 | } |