bin/sh/var.c

   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 1.15.2.2 2002/08/27 01:36:28 tjr Exp $
  38  * $DragonFly: src/bin/sh/var.c,v 1.15 2007/01/14 17:29:58 pavalos Exp $
  39  */
  40
  41 #include <unistd.h>
  42 #include <stdlib.h>
  43
  44 /*
  45  * Shell variables.
  46  */
  47
  48 #include <locale.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 #ifndef NO_HISTORY
  66 #include "myhistedit.h"
  67 #endif
  68
  69
  70 #define VTABSIZE 39
  71
  72
  73 struct varinit {
  74         struct var *var;
  75         int flags;
  76         const char *text;
  77         void (*func)(const char *);
  78 };
  79
  80
  81 #ifndef NO_HISTORY
  82 struct var vhistsize;
  83 #endif
  84 struct var vifs;
  85 struct var vmail;
  86 struct var vmpath;
  87 struct var vpath;
  88 struct var vppid;
  89 struct var vps1;
  90 struct var vps2;
  91 struct var vps4;
  92 struct var vvers;
  93 STATIC struct var voptind;
  94
  95 STATIC 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|VEXPORT,
 107 #ifdef _PATH_DEFPATH
 108                 "PATH=" _PATH_DEFPATH,
 109 #else
 110                 "PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/pkg/bin:/usr/pkg/sbin",
 111 #endif
 112           changepath },
 113         { &vppid,       VSTRFIXED|VTEXTFIXED|VUNSET,    "PPID=",
 114           NULL },
 115         /*
 116          * vps1 depends on uid
 117          */
 118         { &vps2,        VSTRFIXED|VTEXTFIXED,           "PS2=> ",
 119           NULL },
 120         { &vps4,        VSTRFIXED|VTEXTFIXED,           "PS4=+ ",
 121           NULL },
 122         { &voptind,     VSTRFIXED|VTEXTFIXED,           "OPTIND=1",
 123           getoptsreset },
 124         { NULL, 0,                              NULL,
 125           NULL }
 126 };
 127
 128 STATIC struct var *vartab[VTABSIZE];
 129
 130 STATIC struct var **hashvar(const char *);
 131 STATIC int varequal(const char *, const char *);
 132 STATIC int localevar(const char *);
 133
 134 /*
 135  * Initialize the variable symbol tables and import the environment.
 136  */
 137
 138 #ifdef mkinit
 139 INCLUDE "var.h"
 140 MKINIT char **environ;
 141 INIT {
 142         char **envp;
 143
 144         initvar();
 145         for (envp = environ ; *envp ; envp++) {
 146                 if (strchr(*envp, '=')) {
 147                         setvareq(*envp, VEXPORT|VTEXTFIXED);
 148                 }
 149         }
 150 }
 151 #endif
 152
 153
 154 /*
 155  * This routine initializes the builtin variables.  It is called when the
 156  * shell is initialized and again when a shell procedure is spawned.
 157  */
 158
 159 void
 160 initvar(void)
 161 {
 162         char ppid[20];
 163         const struct varinit *ip;
 164         struct var *vp;
 165         struct var **vpp;
 166
 167         for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
 168                 if ((vp->flags & VEXPORT) == 0) {
 169                         vpp = hashvar(ip->text);
 170                         vp->next = *vpp;
 171                         *vpp = vp;
 172                         vp->text = strdup(ip->text);
 173                         vp->flags = ip->flags;
 174                         vp->func = ip->func;
 175                 }
 176         }
 177         /*
 178          * PS1 depends on uid
 179          */
 180         if ((vps1.flags & VEXPORT) == 0) {
 181                 vpp = hashvar("PS1=");
 182                 vps1.next = *vpp;
 183                 *vpp = &vps1;
 184                 vps1.text = strdup(geteuid() ? "PS1=$ " : "PS1=# ");
 185                 vps1.flags = VSTRFIXED|VTEXTFIXED;
 186         }
 187         if ((vppid.flags & VEXPORT) == 0) {
 188                 fmtstr(ppid, sizeof(ppid), "%d", (int)getppid());
 189                 setvarsafe("PPID", ppid, 0);
 190         }
 191 }
 192
 193 /*
 194  * Safe version of setvar, returns 1 on success 0 on failure.
 195  */
 196
 197 int
 198 setvarsafe(const char *name, const char *val, int flags)
 199 {
 200         struct jmploc jmploc;
 201         struct jmploc *volatile savehandler = handler;
 202         int err = 0;
 203
 204         if (setjmp(jmploc.loc))
 205                 err = 1;
 206         else {
 207                 handler = &jmploc;
 208                 setvar(name, val, flags);
 209         }
 210         handler = savehandler;
 211         return err;
 212 }
 213
 214 /*
 215  * Set the value of a variable.  The flags argument is stored with the
 216  * flags of the variable.  If val is NULL, the variable is unset.
 217  */
 218
 219 void
 220 setvar(const char *name, const char *val, int flags)
 221 {
 222         const char *cp;
 223         char *p;
 224         int len;
 225         int namelen;
 226         char *nameeq;
 227         int isbad;
 228
 229         isbad = 0;
 230         cp = name;
 231         if (!is_name(*cp))
 232                 isbad = 1;
 233         cp++;
 234         for (;;) {
 235                 if (!is_in_name(*cp)) {
 236                         if (*cp == '\0' || *cp == '=')
 237                                 break;
 238                         isbad = 1;
 239                 }
 240                 cp++;
 241         }
 242         namelen = cp - name;
 243         if (isbad)
 244                 error("%.*s: bad variable name", namelen, name);
 245         len = namelen + 2;              /* 2 is space for '=' and '\0' */
 246         if (val == NULL) {
 247                 flags |= VUNSET;
 248         } else {
 249                 len += strlen(val);
 250         }
 251         p = nameeq = ckmalloc(len);
 252         cp = name;
 253         while (--namelen >= 0)
 254                 *p++ = *cp++;
 255         *p++ = '=';
 256         *p = '\0';
 257         if (val)
 258                 scopy(val, p);
 259         setvareq(nameeq, flags);
 260 }
 261
 262 STATIC int
 263 localevar(const char *s)
 264 {
 265         static const char * const lnames[7] = {
 266                 "ALL", "COLLATE", "CTYPE", "MONETARY",
 267                 "NUMERIC", "TIME", NULL
 268         };
 269         const char * const *ss;
 270
 271         if (*s != 'L')
 272                 return 0;
 273         if (varequal(s + 1, "ANG"))
 274                 return 1;
 275         if (strncmp(s + 1, "C_", 2) != 0)
 276                 return 0;
 277         for (ss = lnames; *ss ; ss++)
 278                 if (varequal(s + 3, *ss))
 279                         return 1;
 280         return 0;
 281 }
 282
 283 /*
 284  * Sets/unsets an environment variable from a pointer that may actually be a
 285  * pointer into environ where the string should not be manipulated.
 286  */
 287 static void
 288 change_env(char *s, int set)
 289 {
 290         char *eqp;
 291         char *ss;
 292
 293         ss = savestr(s);
 294         if ((eqp = strchr(ss, '=')) != NULL)
 295                 *eqp = '\0';
 296         if (set && eqp != NULL) {
 297                 if (setenv(ss, eqp + 1, 1) != 0)
 298                         error("setenv: cannot set %s=%s", ss, eqp + 1);
 299         } else
 300                 unsetenv(ss);
 301         ckfree(ss);
 302 }
 303
 304
 305 /*
 306  * Same as setvar except that the variable and value are passed in
 307  * the first argument as name=value.  Since the first argument will
 308  * be actually stored in the table, it should not be a string that
 309  * will go away.
 310  */
 311
 312 void
 313 setvareq(char *s, int flags)
 314 {
 315         struct var *vp, **vpp;
 316         int len;
 317
 318         if (aflag)
 319                 flags |= VEXPORT;
 320         vpp = hashvar(s);
 321         for (vp = *vpp ; vp ; vp = vp->next) {
 322                 if (varequal(s, vp->text)) {
 323                         if (vp->flags & VREADONLY) {
 324                                 len = strchr(s, '=') - s;
 325                                 error("%.*s: is read only", len, s);
 326                         }
 327                         INTOFF;
 328
 329                         if (vp->func && (flags & VNOFUNC) == 0)
 330                                 (*vp->func)(strchr(s, '=') + 1);
 331
 332                         if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
 333                                 ckfree(vp->text);
 334
 335                         vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
 336                         vp->flags |= flags;
 337                         vp->text = s;
 338
 339                         /*
 340                          * We could roll this to a function, to handle it as
 341                          * a regular variable function callback, but why bother?
 342                          */
 343                         if (vp == &vmpath || (vp == &vmail && ! mpathset()))
 344                                 chkmail(1);
 345                         if ((vp->flags & VEXPORT) && localevar(s)) {
 346                                 change_env(s, 1);
 347                                 setlocale(LC_ALL, "");
 348                         }
 349                         INTON;
 350                         return;
 351                 }
 352         }
 353         /* not found */
 354         vp = ckmalloc(sizeof (*vp));
 355         vp->flags = flags;
 356         vp->text = s;
 357         vp->next = *vpp;
 358         vp->func = NULL;
 359         INTOFF;
 360         *vpp = vp;
 361         if ((vp->flags & VEXPORT) && localevar(s)) {
 362                 change_env(s, 1);
 363                 setlocale(LC_ALL, "");
 364         }
 365         INTON;
 366 }
 367
 368
 369
 370 /*
 371  * Process a linked list of variable assignments.
 372  */
 373
 374 void
 375 listsetvar(struct strlist *list)
 376 {
 377         struct strlist *lp;
 378
 379         INTOFF;
 380         for (lp = list ; lp ; lp = lp->next) {
 381                 setvareq(savestr(lp->text), 0);
 382         }
 383         INTON;
 384 }
 385
 386
 387
 388 /*
 389  * Find the value of a variable.  Returns NULL if not set.
 390  */
 391
 392 char *
 393 lookupvar(const char *name)
 394 {
 395         struct var *v;
 396
 397         for (v = *hashvar(name) ; v ; v = v->next) {
 398                 if (varequal(v->text, name)) {
 399                         if (v->flags & VUNSET)
 400                                 return NULL;
 401                         return strchr(v->text, '=') + 1;
 402                 }
 403         }
 404         return NULL;
 405 }
 406
 407
 408
 409 /*
 410  * Search the environment of a builtin command.  If the second argument
 411  * is nonzero, return the value of a variable even if it hasn't been
 412  * exported.
 413  */
 414
 415 char *
 416 bltinlookup(const char *name, int doall)
 417 {
 418         struct strlist *sp;
 419         struct var *v;
 420
 421         for (sp = cmdenviron ; sp ; sp = sp->next) {
 422                 if (varequal(sp->text, name))
 423                         return strchr(sp->text, '=') + 1;
 424         }
 425         for (v = *hashvar(name) ; v ; v = v->next) {
 426                 if (varequal(v->text, name)) {
 427                         if ((v->flags & VUNSET)
 428                          || (!doall && (v->flags & VEXPORT) == 0))
 429                                 return NULL;
 430                         return strchr(v->text, '=') + 1;
 431                 }
 432         }
 433         return NULL;
 434 }
 435
 436
 437
 438 /*
 439  * Generate a list of exported variables.  This routine is used to construct
 440  * the third argument to execve when executing a program.
 441  */
 442
 443 char **
 444 environment(void)
 445 {
 446         int nenv;
 447         struct var **vpp;
 448         struct var *vp;
 449         char **env, **ep;
 450
 451         nenv = 0;
 452         for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
 453                 for (vp = *vpp ; vp ; vp = vp->next)
 454                         if (vp->flags & VEXPORT)
 455                                 nenv++;
 456         }
 457         ep = env = stalloc((nenv + 1) * sizeof *env);
 458         for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
 459                 for (vp = *vpp ; vp ; vp = vp->next)
 460                         if (vp->flags & VEXPORT)
 461                                 *ep++ = vp->text;
 462         }
 463         *ep = NULL;
 464         return env;
 465 }
 466
 467
 468 /*
 469  * Called when a shell procedure is invoked to clear out nonexported
 470  * variables.  It is also necessary to reallocate variables of with
 471  * VSTACK set since these are currently allocated on the stack.
 472  */
 473
 474 #ifdef mkinit
 475 void shprocvar(void);
 476
 477 SHELLPROC {
 478         shprocvar();
 479 }
 480 #endif
 481
 482 void
 483 shprocvar(void)
 484 {
 485         struct var **vpp;
 486         struct var *vp, **prev;
 487
 488         for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
 489                 for (prev = vpp ; (vp = *prev) != NULL ; ) {
 490                         if ((vp->flags & VEXPORT) == 0) {
 491                                 *prev = vp->next;
 492                                 if ((vp->flags & VTEXTFIXED) == 0)
 493                                         ckfree(vp->text);
 494                                 if ((vp->flags & VSTRFIXED) == 0)
 495                                         ckfree(vp);
 496                         } else {
 497                                 if (vp->flags & VSTACK) {
 498                                         vp->text = savestr(vp->text);
 499                                         vp->flags &=~ VSTACK;
 500                                 }
 501                                 prev = &vp->next;
 502                         }
 503                 }
 504         }
 505         initvar();
 506 }
 507
 508
 509 static int
 510 var_compare(const void *a, const void *b)
 511 {
 512         const char *const *sa, *const *sb;
 513
 514         sa = a;
 515         sb = b;
 516         /*
 517          * This compares two var=value strings which creates a different
 518          * order from what you would probably expect.  POSIX is somewhat
 519          * ambiguous on what should be sorted exactly.
 520          */
 521         return strcoll(*sa, *sb);
 522 }
 523
 524
 525 /*
 526  * Command to list all variables which are set.  Currently this command
 527  * is invoked from the set command when the set command is called without
 528  * any variables.
 529  */
 530
 531 int
 532 showvarscmd(int argc __unused, char **argv __unused)
 533 {
 534         struct var **vpp;
 535         struct var *vp;
 536         const char *s;
 537         const char **vars;
 538         int i, n;
 539
 540         /*
 541          * POSIX requires us to sort the variables.
 542          */
 543         n = 0;
 544         for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
 545                 for (vp = *vpp; vp; vp = vp->next) {
 546                         if (!(vp->flags & VUNSET))
 547                                 n++;
 548                 }
 549         }
 550
 551         INTON;
 552         vars = ckmalloc(n * sizeof(*vars));
 553         i = 0;
 554         for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
 555                 for (vp = *vpp; vp; vp = vp->next) {
 556                         if (!(vp->flags & VUNSET))
 557                                 vars[i++] = vp->text;
 558                 }
 559         }
 560
 561         qsort(vars, n, sizeof(*vars), var_compare);
 562         for (i = 0; i < n; i++) {
 563                 for (s = vars[i]; *s != '='; s++)
 564                         out1c(*s);
 565                 out1c('=');
 566                 out1qstr(s + 1);
 567                 out1c('\n');
 568         }
 569         ckfree(vars);
 570         INTOFF;
 571
 572         return 0;
 573 }
 574
 575
 576
 577 /*
 578  * The export and readonly commands.
 579  */
 580
 581 int
 582 exportcmd(int argc, char **argv)
 583 {
 584         struct var **vpp;
 585         struct var *vp;
 586         char *name;
 587         char *p;
 588         char *cmdname;
 589         int ch, values;
 590         int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
 591
 592         cmdname = argv[0];
 593         optreset = optind = 1;
 594         opterr = 0;
 595         values = 0;
 596         while ((ch = getopt(argc, argv, "p")) != -1) {
 597                 switch (ch) {
 598                 case 'p':
 599                         values = 1;
 600                         break;
 601                 case '?':
 602                 default:
 603                         error("unknown option: -%c", optopt);
 604                 }
 605         }
 606         argc -= optind;
 607         argv += optind;
 608
 609         if (values && argc != 0)
 610                 error("-p requires no arguments");
 611         listsetvar(cmdenviron);
 612         if (argc != 0) {
 613                 while ((name = *argv++) != NULL) {
 614                         if ((p = strchr(name, '=')) != NULL) {
 615                                 p++;
 616                         } else {
 617                                 vpp = hashvar(name);
 618                                 for (vp = *vpp ; vp ; vp = vp->next) {
 619                                         if (varequal(vp->text, name)) {
 620
 621                                                 vp->flags |= flag;
 622                                                 if ((vp->flags & VEXPORT) && localevar(vp->text)) {
 623                                                         change_env(vp->text, 1);
 624                                                         setlocale(LC_ALL, "");
 625                                                 }
 626                                                 goto found;
 627                                         }
 628                                 }
 629                         }
 630                         setvar(name, p, flag);
 631 found:;
 632                 }
 633         } else {
 634                 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
 635                         for (vp = *vpp ; vp ; vp = vp->next) {
 636                                 if (vp->flags & flag) {
 637                                         if (values) {
 638                                                 out1str(cmdname);
 639                                                 out1c(' ');
 640                                         }
 641                                         for (p = vp->text ; *p != '=' ; p++)
 642                                                 out1c(*p);
 643                                         if (values && !(vp->flags & VUNSET)) {
 644                                                 out1c('=');
 645                                                 out1qstr(p + 1);
 646                                         }
 647                                         out1c('\n');
 648                                 }
 649                         }
 650                 }
 651         }
 652         return 0;
 653 }
 654
 655
 656 /*
 657  * The "local" command.
 658  */
 659
 660 int
 661 localcmd(int argc __unused, char **argv __unused)
 662 {
 663         char *name;
 664
 665         if (! in_function())
 666                 error("Not in a function");
 667         while ((name = *argptr++) != NULL) {
 668                 mklocal(name);
 669         }
 670         return 0;
 671 }
 672
 673
 674 /*
 675  * Make a variable a local variable.  When a variable is made local, it's
 676  * value and flags are saved in a localvar structure.  The saved values
 677  * will be restored when the shell function returns.  We handle the name
 678  * "-" as a special case.
 679  */
 680
 681 void
 682 mklocal(char *name)
 683 {
 684         struct localvar *lvp;
 685         struct var **vpp;
 686         struct var *vp;
 687
 688         INTOFF;
 689         lvp = ckmalloc(sizeof (struct localvar));
 690         if (name[0] == '-' && name[1] == '\0') {
 691                 lvp->text = ckmalloc(sizeof optlist);
 692                 memcpy(lvp->text, optlist, sizeof optlist);
 693                 vp = NULL;
 694         } else {
 695                 vpp = hashvar(name);
 696                 for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next);
 697                 if (vp == NULL) {
 698                         if (strchr(name, '='))
 699                                 setvareq(savestr(name), VSTRFIXED);
 700                         else
 701                                 setvar(name, NULL, VSTRFIXED);
 702                         vp = *vpp;      /* the new variable */
 703                         lvp->text = NULL;
 704                         lvp->flags = VUNSET;
 705                 } else {
 706                         lvp->text = vp->text;
 707                         lvp->flags = vp->flags;
 708                         vp->flags |= VSTRFIXED|VTEXTFIXED;
 709                         if (strchr(name, '='))
 710                                 setvareq(savestr(name), 0);
 711                 }
 712         }
 713         lvp->vp = vp;
 714         lvp->next = localvars;
 715         localvars = lvp;
 716         INTON;
 717 }
 718
 719
 720 /*
 721  * Called after a function returns.
 722  */
 723
 724 void
 725 poplocalvars(void)
 726 {
 727         struct localvar *lvp;
 728         struct var *vp;
 729
 730         while ((lvp = localvars) != NULL) {
 731                 localvars = lvp->next;
 732                 vp = lvp->vp;
 733                 if (vp == NULL) {       /* $- saved */
 734                         memcpy(optlist, lvp->text, sizeof optlist);
 735                         ckfree(lvp->text);
 736                 } else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
 737                         unsetvar(vp->text);
 738                 } else {
 739                         if ((vp->flags & VTEXTFIXED) == 0)
 740                                 ckfree(vp->text);
 741                         vp->flags = lvp->flags;
 742                         vp->text = lvp->text;
 743                 }
 744                 ckfree(lvp);
 745         }
 746 }
 747
 748
 749 int
 750 setvarcmd(int argc, char **argv)
 751 {
 752         if (argc <= 2)
 753                 return unsetcmd(argc, argv);
 754         else if (argc == 3)
 755                 setvar(argv[1], argv[2], 0);
 756         else
 757                 error("List assignment not implemented");
 758         return 0;
 759 }
 760
 761
 762 /*
 763  * The unset builtin command.  We unset the function before we unset the
 764  * variable to allow a function to be unset when there is a readonly variable
 765  * with the same name.
 766  */
 767
 768 int
 769 unsetcmd(int argc __unused, char **argv __unused)
 770 {
 771         char **ap;
 772         int i;
 773         int flg_func = 0;
 774         int flg_var = 0;
 775         int ret = 0;
 776
 777         while ((i = nextopt("vf")) != '\0') {
 778                 if (i == 'f')
 779                         flg_func = 1;
 780                 else
 781                         flg_var = 1;
 782         }
 783         if (flg_func == 0 && flg_var == 0)
 784                 flg_var = 1;
 785
 786         for (ap = argptr; *ap ; ap++) {
 787                 if (flg_func)
 788                         ret |= unsetfunc(*ap);
 789                 if (flg_var)
 790                         ret |= unsetvar(*ap);
 791         }
 792         return ret;
 793 }
 794
 795
 796 /*
 797  * Unset the specified variable.
 798  */
 799
 800 int
 801 unsetvar(const char *s)
 802 {
 803         struct var **vpp;
 804         struct var *vp;
 805
 806         vpp = hashvar(s);
 807         for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
 808                 if (varequal(vp->text, s)) {
 809                         if (vp->flags & VREADONLY)
 810                                 return (1);
 811                         INTOFF;
 812                         if (*(strchr(vp->text, '=') + 1) != '\0')
 813                                 setvar(s, nullstr, 0);
 814                         if ((vp->flags & VEXPORT) && localevar(vp->text)) {
 815                                 change_env(__DECONST(char *, s), 0);
 816                                 setlocale(LC_ALL, "");
 817                         }
 818                         vp->flags &= ~VEXPORT;
 819                         vp->flags |= VUNSET;
 820                         if ((vp->flags & VSTRFIXED) == 0) {
 821                                 if ((vp->flags & VTEXTFIXED) == 0)
 822                                         ckfree(vp->text);
 823                                 *vpp = vp->next;
 824                                 ckfree(vp);
 825                         }
 826                         INTON;
 827                         return (0);
 828                 }
 829         }
 830         return (0);
 831 }
 832
 833
 834
 835 /*
 836  * Find the appropriate entry in the hash table from the name.
 837  */
 838
 839 STATIC struct var **
 840 hashvar(const 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
 858 STATIC int
 859 varequal(const char *p, const 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 }