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 1.13 2007/01/07 01:14:53 pavalos Exp $
  39  */
  40
  41 #include <unistd.h>
  42 #include <stdlib.h>
  43
  44 /*
  45  * Shell variables.
  46  */
  47
  48 #include <locale.h>
  49
  50 #include "shell.h"
  51 #include "output.h"
  52 #include "expand.h"
  53 #include "nodes.h"      /* for other headers */
  54 #include "eval.h"       /* defines cmdenviron */
  55 #include "exec.h"
  56 #include "syntax.h"
  57 #include "options.h"
  58 #include "mail.h"
  59 #include "var.h"
  60 #include "memalloc.h"
  61 #include "error.h"
  62 #include "mystring.h"
  63 #include "parser.h"
  64 #ifndef NO_HISTORY
  65 #include "myhistedit.h"
  66 #endif
  67
  68
  69 #define VTABSIZE 39
  70
  71
  72 struct varinit {
  73         struct var *var;
  74         int flags;
  75         const char *text;
  76         void (*func)(const char *);
  77 };
  78
  79
  80 #ifndef NO_HISTORY
  81 struct var vhistsize;
  82 #endif
  83 struct var vifs;
  84 struct var vmail;
  85 struct var vmpath;
  86 struct var vpath;
  87 struct var vppid;
  88 struct var vps1;
  89 struct var vps2;
  90 struct var vps4;
  91 struct var vvers;
  92 STATIC struct var voptind;
  93
  94 STATIC const struct varinit varinit[] = {
  95 #ifndef NO_HISTORY
  96         { &vhistsize,   VSTRFIXED|VTEXTFIXED|VUNSET,    "HISTSIZE=",
  97           sethistsize },
  98 #endif
  99         { &vifs,        VSTRFIXED|VTEXTFIXED,           "IFS= \t\n",
 100           NULL },
 101         { &vmail,       VSTRFIXED|VTEXTFIXED|VUNSET,    "MAIL=",
 102           NULL },
 103         { &vmpath,      VSTRFIXED|VTEXTFIXED|VUNSET,    "MAILPATH=",
 104           NULL },
 105         { &vpath,       VSTRFIXED|VTEXTFIXED,           "PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/pkg/bin:/usr/pkg/sbin",
 106           changepath },
 107         { &vppid,       VSTRFIXED|VTEXTFIXED|VUNSET,    "PPID=",
 108           NULL },
 109         /*
 110          * vps1 depends on uid
 111          */
 112         { &vps2,        VSTRFIXED|VTEXTFIXED,           "PS2=> ",
 113           NULL },
 114         { &vps4,        VSTRFIXED|VTEXTFIXED,           "PS4=+ ",
 115           NULL },
 116         { &voptind,     VSTRFIXED|VTEXTFIXED,           "OPTIND=1",
 117           getoptsreset },
 118         { NULL, 0,                              NULL,
 119           NULL }
 120 };
 121
 122 STATIC struct var *vartab[VTABSIZE];
 123
 124 STATIC struct var **hashvar(const char *);
 125 STATIC int varequal(const char *, const char *);
 126 STATIC int localevar(const char *);
 127
 128 /*
 129  * Initialize the variable symbol tables and import the environment.
 130  */
 131
 132 #ifdef mkinit
 133 INCLUDE "var.h"
 134 MKINIT char **environ;
 135 INIT {
 136         char **envp;
 137
 138         initvar();
 139         for (envp = environ ; *envp ; envp++) {
 140                 if (strchr(*envp, '=')) {
 141                         setvareq(*envp, VEXPORT|VTEXTFIXED);
 142                 }
 143         }
 144 }
 145 #endif
 146
 147
 148 /*
 149  * This routine initializes the builtin variables.  It is called when the
 150  * shell is initialized and again when a shell procedure is spawned.
 151  */
 152
 153 void
 154 initvar(void)
 155 {
 156         char ppid[20];
 157         const struct varinit *ip;
 158         struct var *vp;
 159         struct var **vpp;
 160
 161         for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
 162                 if ((vp->flags & VEXPORT) == 0) {
 163                         vpp = hashvar(ip->text);
 164                         vp->next = *vpp;
 165                         *vpp = vp;
 166                         vp->text = strdup(ip->text);
 167                         vp->flags = ip->flags;
 168                         vp->func = ip->func;
 169                 }
 170         }
 171         /*
 172          * PS1 depends on uid
 173          */
 174         if ((vps1.flags & VEXPORT) == 0) {
 175                 vpp = hashvar("PS1=");
 176                 vps1.next = *vpp;
 177                 *vpp = &vps1;
 178                 vps1.text = strdup(geteuid() ? "PS1=$ " : "PS1=# ");
 179                 vps1.flags = VSTRFIXED|VTEXTFIXED;
 180         }
 181         if ((vppid.flags & VEXPORT) == 0) {
 182                 fmtstr(ppid, sizeof(ppid), "%d", (int)getppid());
 183                 setvarsafe("PPID", ppid, 0);
 184         }
 185 }
 186
 187 /*
 188  * Safe version of setvar, returns 1 on success 0 on failure.
 189  */
 190
 191 int
 192 setvarsafe(const char *name, const char *val, int flags)
 193 {
 194         struct jmploc jmploc;
 195         struct jmploc *volatile savehandler = handler;
 196         int err = 0;
 197 #if __GNUC__
 198         /* Avoid longjmp clobbering */
 199         (void) &err;
 200 #endif
 201
 202         if (setjmp(jmploc.loc))
 203                 err = 1;
 204         else {
 205                 handler = &jmploc;
 206                 setvar(name, val, flags);
 207         }
 208         handler = savehandler;
 209         return err;
 210 }
 211
 212 /*
 213  * Set the value of a variable.  The flags argument is tored with the
 214  * flags of the variable.  If val is NULL, the variable is unset.
 215  */
 216
 217 void
 218 setvar(const char *name, const char *val, int flags)
 219 {
 220         const char *cp;
 221         char *p;
 222         int len;
 223         int namelen;
 224         char *nameeq;
 225         int isbad;
 226
 227         isbad = 0;
 228         cp = name;
 229         if (!is_name(*cp))
 230                 isbad = 1;
 231         cp++;
 232         for (;;) {
 233                 if (!is_in_name(*cp)) {
 234                         if (*cp == '\0' || *cp == '=')
 235                                 break;
 236                         isbad = 1;
 237                 }
 238                 cp++;
 239         }
 240         namelen = cp - 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         cp = name;
 251         while (--namelen >= 0)
 252                 *p++ = *cp++;
 253         *p++ = '=';
 254         *p = '\0';
 255         if (val)
 256                 scopy(val, p);
 257         setvareq(nameeq, flags);
 258 }
 259
 260 STATIC int
 261 localevar(const char *s)
 262 {
 263         static const char * const lnames[7] = {
 264                 "ALL", "COLLATE", "CTYPE", "MONETARY",
 265                 "NUMERIC", "TIME", NULL
 266         };
 267         const char * const *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
 288 void
 289 setvareq(char *s, int flags)
 290 {
 291         struct var *vp, **vpp;
 292         int len;
 293
 294         if (aflag)
 295                 flags |= VEXPORT;
 296         vpp = hashvar(s);
 297         for (vp = *vpp ; vp ; vp = vp->next) {
 298                 if (varequal(s, vp->text)) {
 299                         if (vp->flags & VREADONLY) {
 300                                 len = strchr(s, '=') - s;
 301                                 error("%.*s: is read only", len, s);
 302                         }
 303                         INTOFF;
 304
 305                         if (vp->func && (flags & VNOFUNC) == 0)
 306                                 (*vp->func)(strchr(s, '=') + 1);
 307
 308                         if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
 309                                 ckfree(vp->text);
 310
 311                         vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
 312                         vp->flags |= flags;
 313                         vp->text = s;
 314
 315                         /*
 316                          * We could roll this to a function, to handle it as
 317                          * a regular variable function callback, but why bother?
 318                          */
 319                         if (vp == &vmpath || (vp == &vmail && ! mpathset()))
 320                                 chkmail(1);
 321                         if ((vp->flags & VEXPORT) && localevar(s)) {
 322                                 if (putenv(s) != 0)
 323                                         error("putenv: cannot set %s", s);
 324                                 setlocale(LC_ALL, "");
 325                         }
 326                         INTON;
 327                         return;
 328                 }
 329         }
 330         /* not found */
 331         vp = ckmalloc(sizeof (*vp));
 332         vp->flags = flags;
 333         vp->text = s;
 334         vp->next = *vpp;
 335         vp->func = NULL;
 336         INTOFF;
 337         *vpp = vp;
 338         if ((vp->flags & VEXPORT) && localevar(s)) {
 339                 if (putenv(s) != 0)
 340                         error("putenv: cannot set %s", s);
 341                 setlocale(LC_ALL, "");
 342         }
 343         INTON;
 344 }
 345
 346
 347
 348 /*
 349  * Process a linked list of variable assignments.
 350  */
 351
 352 void
 353 listsetvar(struct strlist *list)
 354 {
 355         struct strlist *lp;
 356
 357         INTOFF;
 358         for (lp = list ; lp ; lp = lp->next) {
 359                 setvareq(savestr(lp->text), 0);
 360         }
 361         INTON;
 362 }
 363
 364
 365
 366 /*
 367  * Find the value of a variable.  Returns NULL if not set.
 368  */
 369
 370 char *
 371 lookupvar(const char *name)
 372 {
 373         struct var *v;
 374
 375         for (v = *hashvar(name) ; v ; v = v->next) {
 376                 if (varequal(v->text, name)) {
 377                         if (v->flags & VUNSET)
 378                                 return NULL;
 379                         return strchr(v->text, '=') + 1;
 380                 }
 381         }
 382         return NULL;
 383 }
 384
 385
 386
 387 /*
 388  * Search the environment of a builtin command.  If the second argument
 389  * is nonzero, return the value of a variable even if it hasn't been
 390  * exported.
 391  */
 392
 393 char *
 394 bltinlookup(const char *name, int doall)
 395 {
 396         struct strlist *sp;
 397         struct var *v;
 398
 399         for (sp = cmdenviron ; sp ; sp = sp->next) {
 400                 if (varequal(sp->text, name))
 401                         return strchr(sp->text, '=') + 1;
 402         }
 403         for (v = *hashvar(name) ; v ; v = v->next) {
 404                 if (varequal(v->text, name)) {
 405                         if ((v->flags & VUNSET)
 406                          || (!doall && (v->flags & VEXPORT) == 0))
 407                                 return NULL;
 408                         return strchr(v->text, '=') + 1;
 409                 }
 410         }
 411         return NULL;
 412 }
 413
 414
 415
 416 /*
 417  * Generate a list of exported variables.  This routine is used to construct
 418  * the third argument to execve when executing a program.
 419  */
 420
 421 char **
 422 environment(void)
 423 {
 424         int nenv;
 425         struct var **vpp;
 426         struct var *vp;
 427         char **env, **ep;
 428
 429         nenv = 0;
 430         for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
 431                 for (vp = *vpp ; vp ; vp = vp->next)
 432                         if (vp->flags & VEXPORT)
 433                                 nenv++;
 434         }
 435         ep = env = stalloc((nenv + 1) * sizeof *env);
 436         for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
 437                 for (vp = *vpp ; vp ; vp = vp->next)
 438                         if (vp->flags & VEXPORT)
 439                                 *ep++ = vp->text;
 440         }
 441         *ep = NULL;
 442         return env;
 443 }
 444
 445
 446 /*
 447  * Called when a shell procedure is invoked to clear out nonexported
 448  * variables.  It is also necessary to reallocate variables of with
 449  * VSTACK set since these are currently allocated on the stack.
 450  */
 451
 452 #ifdef mkinit
 453 void shprocvar(void);
 454
 455 SHELLPROC {
 456         shprocvar();
 457 }
 458 #endif
 459
 460 void
 461 shprocvar(void)
 462 {
 463         struct var **vpp;
 464         struct var *vp, **prev;
 465
 466         for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
 467                 for (prev = vpp ; (vp = *prev) != NULL ; ) {
 468                         if ((vp->flags & VEXPORT) == 0) {
 469                                 *prev = vp->next;
 470                                 if ((vp->flags & VTEXTFIXED) == 0)
 471                                         ckfree(vp->text);
 472                                 if ((vp->flags & VSTRFIXED) == 0)
 473                                         ckfree(vp);
 474                         } else {
 475                                 if (vp->flags & VSTACK) {
 476                                         vp->text = savestr(vp->text);
 477                                         vp->flags &=~ VSTACK;
 478                                 }
 479                                 prev = &vp->next;
 480                         }
 481                 }
 482         }
 483         initvar();
 484 }
 485
 486
 487
 488 /*
 489  * Command to list all variables which are set.  Currently this command
 490  * is invoked from the set command when the set command is called without
 491  * any variables.
 492  */
 493
 494 int
 495 showvarscmd(int argc __unused, char **argv __unused)
 496 {
 497         struct var **vpp;
 498         struct var *vp;
 499         const char *s;
 500
 501         for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
 502                 for (vp = *vpp ; vp ; vp = vp->next) {
 503                         if (vp->flags & VUNSET)
 504                                 continue;
 505                         for (s = vp->text; *s != '='; s++)
 506                                 out1c(*s);
 507                         out1c('=');
 508                         out1qstr(s + 1);
 509                         out1c('\n');
 510                 }
 511         }
 512         return 0;
 513 }
 514
 515
 516
 517 /*
 518  * The export and readonly commands.
 519  */
 520
 521 int
 522 exportcmd(int argc, char **argv)
 523 {
 524         struct var **vpp;
 525         struct var *vp;
 526         char *name;
 527         char *p;
 528         char *cmdname;
 529         int ch, values;
 530         int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
 531
 532         cmdname = argv[0];
 533         optreset = optind = 1;
 534         opterr = 0;
 535         values = 0;
 536         while ((ch = getopt(argc, argv, "p")) != -1) {
 537                 switch (ch) {
 538                 case 'p':
 539                         values = 1;
 540                         break;
 541                 case '?':
 542                 default:
 543                         error("unknown option: -%c", optopt);
 544                 }
 545         }
 546         argc -= optind;
 547         argv += optind;
 548
 549         listsetvar(cmdenviron);
 550         if (argc != 0) {
 551                 while ((name = *argptr++) != NULL) {
 552                         if ((p = strchr(name, '=')) != NULL) {
 553                                 p++;
 554                         } else {
 555                                 vpp = hashvar(name);
 556                                 for (vp = *vpp ; vp ; vp = vp->next) {
 557                                         if (varequal(vp->text, name)) {
 558
 559                                                 vp->flags |= flag;
 560                                                 if ((vp->flags & VEXPORT) && localevar(vp->text)) {
 561                                                         if (putenv(vp->text) != 0)
 562                                                                 error("putenv: cannot set %s", vp->text);
 563                                                         setlocale(LC_ALL, "");
 564                                                 }
 565                                                 goto found;
 566                                         }
 567                                 }
 568                         }
 569                         setvar(name, p, flag);
 570 found:;
 571                 }
 572         } else {
 573                 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
 574                         for (vp = *vpp ; vp ; vp = vp->next) {
 575                                 if (vp->flags & flag) {
 576                                         if (values) {
 577                                                 out1str(cmdname);
 578                                                 out1c(' ');
 579                                         }
 580                                         for (p = vp->text ; *p != '=' ; p++)
 581                                                 out1c(*p);
 582                                         if (values && !(vp->flags & VUNSET)) {
 583                                                 out1c('=');
 584                                                 out1qstr(p + 1);
 585                                         }
 586                                         out1c('\n');
 587                                 }
 588                         }
 589                 }
 590         }
 591         return 0;
 592 }
 593
 594
 595 /*
 596  * The "local" command.
 597  */
 598
 599 int
 600 localcmd(int argc __unused, char **argv __unused)
 601 {
 602         char *name;
 603
 604         if (! in_function())
 605                 error("Not in a function");
 606         while ((name = *argptr++) != NULL) {
 607                 mklocal(name);
 608         }
 609         return 0;
 610 }
 611
 612
 613 /*
 614  * Make a variable a local variable.  When a variable is made local, it's
 615  * value and flags are saved in a localvar structure.  The saved values
 616  * will be restored when the shell function returns.  We handle the name
 617  * "-" as a special case.
 618  */
 619
 620 void
 621 mklocal(char *name)
 622 {
 623         struct localvar *lvp;
 624         struct var **vpp;
 625         struct var *vp;
 626
 627         INTOFF;
 628         lvp = ckmalloc(sizeof (struct localvar));
 629         if (name[0] == '-' && name[1] == '\0') {
 630                 lvp->text = ckmalloc(sizeof optlist);
 631                 memcpy(lvp->text, optlist, sizeof optlist);
 632                 vp = NULL;
 633         } else {
 634                 vpp = hashvar(name);
 635                 for (vp = *vpp ; vp && ! varequal(vp->text, name) ; vp = vp->next);
 636                 if (vp == NULL) {
 637                         if (strchr(name, '='))
 638                                 setvareq(savestr(name), VSTRFIXED);
 639                         else
 640                                 setvar(name, NULL, VSTRFIXED);
 641                         vp = *vpp;      /* the new variable */
 642                         lvp->text = NULL;
 643                         lvp->flags = VUNSET;
 644                 } else {
 645                         lvp->text = vp->text;
 646                         lvp->flags = vp->flags;
 647                         vp->flags |= VSTRFIXED|VTEXTFIXED;
 648                         if (strchr(name, '='))
 649                                 setvareq(savestr(name), 0);
 650                 }
 651         }
 652         lvp->vp = vp;
 653         lvp->next = localvars;
 654         localvars = lvp;
 655         INTON;
 656 }
 657
 658
 659 /*
 660  * Called after a function returns.
 661  */
 662
 663 void
 664 poplocalvars(void)
 665 {
 666         struct localvar *lvp;
 667         struct var *vp;
 668
 669         while ((lvp = localvars) != NULL) {
 670                 localvars = lvp->next;
 671                 vp = lvp->vp;
 672                 if (vp == NULL) {       /* $- saved */
 673                         memcpy(optlist, lvp->text, sizeof optlist);
 674                         ckfree(lvp->text);
 675                 } else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
 676                         unsetvar(vp->text);
 677                 } else {
 678                         if ((vp->flags & VTEXTFIXED) == 0)
 679                                 ckfree(vp->text);
 680                         vp->flags = lvp->flags;
 681                         vp->text = lvp->text;
 682                 }
 683                 ckfree(lvp);
 684         }
 685 }
 686
 687
 688 int
 689 setvarcmd(int argc, char **argv)
 690 {
 691         if (argc <= 2)
 692                 return unsetcmd(argc, argv);
 693         else if (argc == 3)
 694                 setvar(argv[1], argv[2], 0);
 695         else
 696                 error("List assignment not implemented");
 697         return 0;
 698 }
 699
 700
 701 /*
 702  * The unset builtin command.  We unset the function before we unset the
 703  * variable to allow a function to be unset when there is a readonly variable
 704  * with the same name.
 705  */
 706
 707 int
 708 unsetcmd(int argc __unused, char **argv __unused)
 709 {
 710         char **ap;
 711         int i;
 712         int flg_func = 0;
 713         int flg_var = 0;
 714         int ret = 0;
 715
 716         while ((i = nextopt("vf")) != '\0') {
 717                 if (i == 'f')
 718                         flg_func = 1;
 719                 else
 720                         flg_var = 1;
 721         }
 722         if (flg_func == 0 && flg_var == 0)
 723                 flg_var = 1;
 724
 725         for (ap = argptr; *ap ; ap++) {
 726                 if (flg_func)
 727                         ret |= unsetfunc(*ap);
 728                 if (flg_var)
 729                         ret |= unsetvar(*ap);
 730         }
 731         return ret;
 732 }
 733
 734
 735 /*
 736  * Unset the specified variable.
 737  */
 738
 739 int
 740 unsetvar(const char *s)
 741 {
 742         struct var **vpp;
 743         struct var *vp;
 744
 745         vpp = hashvar(s);
 746         for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
 747                 if (varequal(vp->text, s)) {
 748                         if (vp->flags & VREADONLY)
 749                                 return (1);
 750                         INTOFF;
 751                         if (*(strchr(vp->text, '=') + 1) != '\0')
 752                                 setvar(s, nullstr, 0);
 753                         if ((vp->flags & VEXPORT) && localevar(vp->text)) {
 754                                 unsetenv(s);
 755                                 setlocale(LC_ALL, "");
 756                         }
 757                         vp->flags &= ~VEXPORT;
 758                         vp->flags |= VUNSET;
 759                         if ((vp->flags & VSTRFIXED) == 0) {
 760                                 if ((vp->flags & VTEXTFIXED) == 0)
 761                                         ckfree(vp->text);
 762                                 *vpp = vp->next;
 763                                 ckfree(vp);
 764                         }
 765                         INTON;
 766                         return (0);
 767                 }
 768         }
 769         return (0);
 770 }
 771
 772
 773
 774 /*
 775  * Find the appropriate entry in the hash table from the name.
 776  */
 777
 778 STATIC struct var **
 779 hashvar(const char *p)
 780 {
 781         unsigned int hashval;
 782
 783         hashval = ((unsigned char) *p) << 4;
 784         while (*p && *p != '=')
 785                 hashval += (unsigned char) *p++;
 786         return &vartab[hashval % VTABSIZE];
 787 }
 788
 789
 790
 791 /*
 792  * Returns true if the two strings specify the same varable.  The first
 793  * variable name is terminated by '='; the second may be terminated by
 794  * either '=' or '\0'.
 795  */
 796
 797 STATIC int
 798 varequal(const char *p, const char *q)
 799 {
 800         while (*p == *q++) {
 801                 if (*p++ == '=')
 802                         return 1;
 803         }
 804         if (*p == '=' && *(q - 1) == '\0')
 805                 return 1;
 806         return 0;
 807 }