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. 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
  35 static char sccsid[] = "@(#)var.c       8.3 (Berkeley) 5/4/95";
  36 #endif
  37 #endif /* not lint */
  38 #include <sys/cdefs.h>
  39 __FBSDID("$FreeBSD$");
  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 #include <langinfo.h>
  51
  52 #include "shell.h"
  53 #include "output.h"
  54 #include "expand.h"
  55 #include "nodes.h"      /* for other headers */
  56 #include "eval.h"       /* defines cmdenviron */
  57 #include "exec.h"
  58 #include "syntax.h"
  59 #include "options.h"
  60 #include "mail.h"
  61 #include "var.h"
  62 #include "memalloc.h"
  63 #include "error.h"
  64 #include "mystring.h"
  65 #include "parser.h"
  66 #include "builtins.h"
  67 #ifndef NO_HISTORY
  68 #include "myhistedit.h"
  69 #endif
  70
  71
  72 #define VTABSIZE 39
  73
  74
  75 struct varinit {
  76         struct var *var;
  77         int flags;
  78         const char *text;
  79         void (*func)(const char *);
  80 };
  81
  82
  83 #ifndef NO_HISTORY
  84 struct var vhistsize;
  85 struct var vterm;
  86 #endif
  87 struct var vifs;
  88 struct var vmail;
  89 struct var vmpath;
  90 struct var vpath;
  91 struct var vps1;
  92 struct var vps2;
  93 struct var vps4;
  94 static struct var voptind;
  95 struct var vdisvfork;
  96
  97 struct localvar *localvars;
  98 int forcelocal;
  99
 100 static const struct varinit varinit[] = {
 101 #ifndef NO_HISTORY
 102         { &vhistsize,   VUNSET,                         "HISTSIZE=",
 103           sethistsize },
 104 #endif
 105         { &vifs,        0,                              "IFS= \t\n",
 106           NULL },
 107         { &vmail,       VUNSET,                         "MAIL=",
 108           NULL },
 109         { &vmpath,      VUNSET,                         "MAILPATH=",
 110           NULL },
 111         { &vpath,       0,                              "PATH=" _PATH_DEFPATH,
 112           changepath },
 113         /*
 114          * vps1 depends on uid
 115          */
 116         { &vps2,        0,                              "PS2=> ",
 117           NULL },
 118         { &vps4,        0,                              "PS4=+ ",
 119           NULL },
 120 #ifndef NO_HISTORY
 121         { &vterm,       VUNSET,                         "TERM=",
 122           setterm },
 123 #endif
 124         { &voptind,     0,                              "OPTIND=1",
 125           getoptsreset },
 126         { &vdisvfork,   VUNSET,                         "SH_DISABLE_VFORK=",
 127           NULL },
 128         { NULL, 0,                              NULL,
 129           NULL }
 130 };
 131
 132 static struct var *vartab[VTABSIZE];
 133
 134 static const char *const locale_names[7] = {
 135         "LC_COLLATE", "LC_CTYPE", "LC_MONETARY",
 136         "LC_NUMERIC", "LC_TIME", "LC_MESSAGES", NULL
 137 };
 138 static const int locale_categories[7] = {
 139         LC_COLLATE, LC_CTYPE, LC_MONETARY, LC_NUMERIC, LC_TIME, LC_MESSAGES, 0
 140 };
 141
 142 static int varequal(const char *, const char *);
 143 static struct var *find_var(const char *, struct var ***, int *);
 144 static int localevar(const char *);
 145 static void setvareq_const(const char *s, int flags);
 146
 147 extern char **environ;
 148
 149 /*
 150  * This routine initializes the builtin variables and imports the environment.
 151  * It is called when the shell is initialized.
 152  */
 153
 154 void
 155 initvar(void)
 156 {
 157         char ppid[20];
 158         const struct varinit *ip;
 159         struct var *vp;
 160         struct var **vpp;
 161         char **envp;
 162
 163         for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
 164                 if (find_var(ip->text, &vpp, &vp->name_len) != NULL)
 165                         continue;
 166                 vp->next = *vpp;
 167                 *vpp = vp;
 168                 vp->text = __DECONST(char *, ip->text);
 169                 vp->flags = ip->flags | VSTRFIXED | VTEXTFIXED;
 170                 vp->func = ip->func;
 171         }
 172         /*
 173          * PS1 depends on uid
 174          */
 175         if (find_var("PS1", &vpp, &vps1.name_len) == NULL) {
 176                 vps1.next = *vpp;
 177                 *vpp = &vps1;
 178                 vps1.text = __DECONST(char *, geteuid() ? "PS1=$ " : "PS1=# ");
 179                 vps1.flags = VSTRFIXED|VTEXTFIXED;
 180         }
 181                 fmtstr(ppid, sizeof(ppid), "%d", (int)getppid());
 182                 setvarsafe("PPID", ppid, 0);
 183         for (envp = environ ; *envp ; envp++) {
 184                 if (strchr(*envp, '=')) {
 185                         setvareq(*envp, VEXPORT|VTEXTFIXED);
 186                 }
 187         }
 188         setvareq_const("OPTIND=1", 0);
 189 }
 190
 191 /*
 192  * Safe version of setvar, returns 1 on success 0 on failure.
 193  */
 194
 195 int
 196 setvarsafe(const char *name, const char *val, int flags)
 197 {
 198         struct jmploc jmploc;
 199         struct jmploc *const savehandler = handler;
 200         int err = 0;
 201         int inton;
 202
 203         inton = is_int_on();
 204         if (setjmp(jmploc.loc))
 205                 err = 1;
 206         else {
 207                 handler = &jmploc;
 208                 setvar(name, val, flags);
 209         }
 210         handler = savehandler;
 211         SETINTON(inton);
 212         return err;
 213 }
 214
 215 /*
 216  * Set the value of a variable.  The flags argument is stored with the
 217  * flags of the variable.  If val is NULL, the variable is unset.
 218  */
 219
 220 void
 221 setvar(const char *name, const char *val, int flags)
 222 {
 223         const char *p;
 224         size_t len;
 225         size_t namelen;
 226         size_t vallen;
 227         char *nameeq;
 228         int isbad;
 229
 230         isbad = 0;
 231         p = name;
 232         if (!is_name(*p))
 233                 isbad = 1;
 234         p++;
 235         for (;;) {
 236                 if (!is_in_name(*p)) {
 237                         if (*p == '\0' || *p == '=')
 238                                 break;
 239                         isbad = 1;
 240                 }
 241                 p++;
 242         }
 243         namelen = p - name;
 244         if (isbad)
 245                 error("%.*s: bad variable name", (int)namelen, name);
 246         len = namelen + 2;              /* 2 is space for '=' and '\0' */
 247         if (val == NULL) {
 248                 flags |= VUNSET;
 249                 vallen = 0;
 250         } else {
 251                 vallen = strlen(val);
 252                 len += vallen;
 253         }
 254         INTOFF;
 255         nameeq = ckmalloc(len);
 256         memcpy(nameeq, name, namelen);
 257         nameeq[namelen] = '=';
 258         if (val)
 259                 memcpy(nameeq + namelen + 1, val, vallen + 1);
 260         else
 261                 nameeq[namelen + 1] = '\0';
 262         setvareq(nameeq, flags);
 263         INTON;
 264 }
 265
 266 static int
 267 localevar(const char *s)
 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         if (varequal(s + 3, "ALL"))
 278                 return 1;
 279         for (ss = locale_names; *ss ; ss++)
 280                 if (varequal(s + 3, *ss + 3))
 281                         return 1;
 282         return 0;
 283 }
 284
 285
 286 /*
 287  * Sets/unsets an environment variable from a pointer that may actually be a
 288  * pointer into environ where the string should not be manipulated.
 289  */
 290 static void
 291 change_env(const char *s, int set)
 292 {
 293         char *eqp;
 294         char *ss;
 295
 296         INTOFF;
 297         ss = savestr(s);
 298         if ((eqp = strchr(ss, '=')) != NULL)
 299                 *eqp = '\0';
 300         if (set && eqp != NULL)
 301                 (void) setenv(ss, eqp + 1, 1);
 302         else
 303                 (void) unsetenv(ss);
 304         ckfree(ss);
 305         INTON;
 306
 307         return;
 308 }
 309
 310
 311 /*
 312  * Same as setvar except that the variable and value are passed in
 313  * the first argument as name=value.  Since the first argument will
 314  * be actually stored in the table, it should not be a string that
 315  * will go away.
 316  */
 317
 318 void
 319 setvareq(char *s, int flags)
 320 {
 321         struct var *vp, **vpp;
 322         int nlen;
 323
 324         if (aflag)
 325                 flags |= VEXPORT;
 326         if (forcelocal && !(flags & (VNOSET | VNOLOCAL)))
 327                 mklocal(s);
 328         vp = find_var(s, &vpp, &nlen);
 329         if (vp != NULL) {
 330                 if (vp->flags & VREADONLY) {
 331                         if ((flags & (VTEXTFIXED|VSTACK)) == 0)
 332                                 ckfree(s);
 333                         error("%.*s: is read only", vp->name_len, s);
 334                 }
 335                 if (flags & VNOSET) {
 336                         if ((flags & (VTEXTFIXED|VSTACK)) == 0)
 337                                 ckfree(s);
 338                         return;
 339                 }
 340                 INTOFF;
 341
 342                 if (vp->func && (flags & VNOFUNC) == 0)
 343                         (*vp->func)(s + vp->name_len + 1);
 344
 345                 if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
 346                         ckfree(vp->text);
 347
 348                 vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
 349                 vp->flags |= flags;
 350                 vp->text = s;
 351
 352                 /*
 353                  * We could roll this to a function, to handle it as
 354                  * a regular variable function callback, but why bother?
 355                  *
 356                  * Note: this assumes iflag is not set to 1 initially.
 357                  * As part of initvar(), this is called before arguments
 358                  * are looked at.
 359                  */
 360                 if ((vp == &vmpath || (vp == &vmail && ! mpathset())) &&
 361                     iflag == 1)
 362                         chkmail(1);
 363                 if ((vp->flags & VEXPORT) && localevar(s)) {
 364                         change_env(s, 1);
 365                         (void) setlocale(LC_ALL, "");
 366                         updatecharset();
 367                 }
 368                 INTON;
 369                 return;
 370         }
 371         /* not found */
 372         if (flags & VNOSET) {
 373                 if ((flags & (VTEXTFIXED|VSTACK)) == 0)
 374                         ckfree(s);
 375                 return;
 376         }
 377         INTOFF;
 378         vp = ckmalloc(sizeof (*vp));
 379         vp->flags = flags;
 380         vp->text = s;
 381         vp->name_len = nlen;
 382         vp->next = *vpp;
 383         vp->func = NULL;
 384         *vpp = vp;
 385         if ((vp->flags & VEXPORT) && localevar(s)) {
 386                 change_env(s, 1);
 387                 (void) setlocale(LC_ALL, "");
 388                 updatecharset();
 389         }
 390         INTON;
 391 }
 392
 393
 394 static void
 395 setvareq_const(const char *s, int flags)
 396 {
 397         setvareq(__DECONST(char *, s), flags | VTEXTFIXED);
 398 }
 399
 400
 401 /*
 402  * Process a linked list of variable assignments.
 403  */
 404
 405 void
 406 listsetvar(struct strlist *list, int flags)
 407 {
 408         struct strlist *lp;
 409
 410         INTOFF;
 411         for (lp = list ; lp ; lp = lp->next) {
 412                 setvareq(savestr(lp->text), flags);
 413         }
 414         INTON;
 415 }
 416
 417
 418
 419 /*
 420  * Find the value of a variable.  Returns NULL if not set.
 421  */
 422
 423 char *
 424 lookupvar(const char *name)
 425 {
 426         struct var *v;
 427
 428         v = find_var(name, NULL, NULL);
 429         if (v == NULL || v->flags & VUNSET)
 430                 return NULL;
 431         return v->text + v->name_len + 1;
 432 }
 433
 434
 435
 436 /*
 437  * Search the environment of a builtin command.  If the second argument
 438  * is nonzero, return the value of a variable even if it hasn't been
 439  * exported.
 440  */
 441
 442 char *
 443 bltinlookup(const char *name, int doall)
 444 {
 445         struct strlist *sp;
 446         struct var *v;
 447         char *result;
 448
 449         result = NULL;
 450         for (sp = cmdenviron ; sp ; sp = sp->next) {
 451                 if (varequal(sp->text, name))
 452                         result = strchr(sp->text, '=') + 1;
 453         }
 454         if (result != NULL)
 455                 return result;
 456
 457         v = find_var(name, NULL, NULL);
 458         if (v == NULL || v->flags & VUNSET ||
 459             (!doall && (v->flags & VEXPORT) == 0))
 460                 return NULL;
 461         return v->text + v->name_len + 1;
 462 }
 463
 464
 465 /*
 466  * Set up locale for a builtin (LANG/LC_* assignments).
 467  */
 468 void
 469 bltinsetlocale(void)
 470 {
 471         struct strlist *lp;
 472         int act = 0;
 473         char *loc, *locdef;
 474         int i;
 475
 476         for (lp = cmdenviron ; lp ; lp = lp->next) {
 477                 if (localevar(lp->text)) {
 478                         act = 1;
 479                         break;
 480                 }
 481         }
 482         if (!act)
 483                 return;
 484         loc = bltinlookup("LC_ALL", 0);
 485         INTOFF;
 486         if (loc != NULL) {
 487                 setlocale(LC_ALL, loc);
 488                 INTON;
 489                 updatecharset();
 490                 return;
 491         }
 492         locdef = bltinlookup("LANG", 0);
 493         for (i = 0; locale_names[i] != NULL; i++) {
 494                 loc = bltinlookup(locale_names[i], 0);
 495                 if (loc == NULL)
 496                         loc = locdef;
 497                 if (loc != NULL)
 498                         setlocale(locale_categories[i], loc);
 499         }
 500         INTON;
 501         updatecharset();
 502 }
 503
 504 /*
 505  * Undo the effect of bltinlocaleset().
 506  */
 507 void
 508 bltinunsetlocale(void)
 509 {
 510         struct strlist *lp;
 511
 512         INTOFF;
 513         for (lp = cmdenviron ; lp ; lp = lp->next) {
 514                 if (localevar(lp->text)) {
 515                         setlocale(LC_ALL, "");
 516                         updatecharset();
 517                         return;
 518                 }
 519         }
 520         INTON;
 521 }
 522
 523 /*
 524  * Update the localeisutf8 flag.
 525  */
 526 void
 527 updatecharset(void)
 528 {
 529         char *charset;
 530
 531         charset = nl_langinfo(CODESET);
 532         localeisutf8 = !strcmp(charset, "UTF-8");
 533 }
 534
 535 void
 536 initcharset(void)
 537 {
 538         updatecharset();
 539         initial_localeisutf8 = localeisutf8;
 540 }
 541
 542 /*
 543  * Generate a list of exported variables.  This routine is used to construct
 544  * the third argument to execve when executing a program.
 545  */
 546
 547 char **
 548 environment(void)
 549 {
 550         int nenv;
 551         struct var **vpp;
 552         struct var *vp;
 553         char **env, **ep;
 554
 555         nenv = 0;
 556         for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
 557                 for (vp = *vpp ; vp ; vp = vp->next)
 558                         if (vp->flags & VEXPORT)
 559                                 nenv++;
 560         }
 561         ep = env = stalloc((nenv + 1) * sizeof *env);
 562         for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
 563                 for (vp = *vpp ; vp ; vp = vp->next)
 564                         if (vp->flags & VEXPORT)
 565                                 *ep++ = vp->text;
 566         }
 567         *ep = NULL;
 568         return env;
 569 }
 570
 571
 572 static int
 573 var_compare(const void *a, const void *b)
 574 {
 575         const char *const *sa, *const *sb;
 576
 577         sa = a;
 578         sb = b;
 579         /*
 580          * This compares two var=value strings which creates a different
 581          * order from what you would probably expect.  POSIX is somewhat
 582          * ambiguous on what should be sorted exactly.
 583          */
 584         return strcoll(*sa, *sb);
 585 }
 586
 587
 588 /*
 589  * Command to list all variables which are set.  This is invoked from the
 590  * set command when it is called without any options or operands.
 591  */
 592
 593 int
 594 showvarscmd(int argc __unused, char **argv __unused)
 595 {
 596         struct var **vpp;
 597         struct var *vp;
 598         const char *s;
 599         const char **vars;
 600         int i, n;
 601
 602         /*
 603          * POSIX requires us to sort the variables.
 604          */
 605         n = 0;
 606         for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
 607                 for (vp = *vpp; vp; vp = vp->next) {
 608                         if (!(vp->flags & VUNSET))
 609                                 n++;
 610                 }
 611         }
 612
 613         INTOFF;
 614         vars = ckmalloc(n * sizeof(*vars));
 615         i = 0;
 616         for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
 617                 for (vp = *vpp; vp; vp = vp->next) {
 618                         if (!(vp->flags & VUNSET))
 619                                 vars[i++] = vp->text;
 620                 }
 621         }
 622
 623         qsort(vars, n, sizeof(*vars), var_compare);
 624         for (i = 0; i < n; i++) {
 625                 /*
 626                  * Skip improper variable names so the output remains usable as
 627                  * shell input.
 628                  */
 629                 if (!isassignment(vars[i]))
 630                         continue;
 631                 s = strchr(vars[i], '=');
 632                 s++;
 633                 outbin(vars[i], s - vars[i], out1);
 634                 out1qstr(s);
 635                 out1c('\n');
 636         }
 637         ckfree(vars);
 638         INTON;
 639
 640         return 0;
 641 }
 642
 643
 644
 645 /*
 646  * The export and readonly commands.
 647  */
 648
 649 int
 650 exportcmd(int argc __unused, char **argv)
 651 {
 652         struct var **vpp;
 653         struct var *vp;
 654         char **ap;
 655         char *name;
 656         char *p;
 657         char *cmdname;
 658         int ch, values;
 659         int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
 660
 661         cmdname = argv[0];
 662         values = 0;
 663         while ((ch = nextopt("p")) != '\0') {
 664                 switch (ch) {
 665                 case 'p':
 666                         values = 1;
 667                         break;
 668                 }
 669         }
 670
 671         if (values && *argptr != NULL)
 672                 error("-p requires no arguments");
 673         if (*argptr != NULL) {
 674                 for (ap = argptr; (name = *ap) != NULL; ap++) {
 675                         if ((p = strchr(name, '=')) != NULL) {
 676                                 p++;
 677                         } else {
 678                                 vp = find_var(name, NULL, NULL);
 679                                 if (vp != NULL) {
 680                                         vp->flags |= flag;
 681                                         if ((vp->flags & VEXPORT) && localevar(vp->text)) {
 682                                                 change_env(vp->text, 1);
 683                                                 (void) setlocale(LC_ALL, "");
 684                                                 updatecharset();
 685                                         }
 686                                         continue;
 687                                 }
 688                         }
 689                         setvar(name, p, flag);
 690                 }
 691         } else {
 692                 for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
 693                         for (vp = *vpp ; vp ; vp = vp->next) {
 694                                 if (vp->flags & flag) {
 695                                         if (values) {
 696                                                 /*
 697                                                  * Skip improper variable names
 698                                                  * so the output remains usable
 699                                                  * as shell input.
 700                                                  */
 701                                                 if (!isassignment(vp->text))
 702                                                         continue;
 703                                                 out1str(cmdname);
 704                                                 out1c(' ');
 705                                         }
 706                                         if (values && !(vp->flags & VUNSET)) {
 707                                                 outbin(vp->text,
 708                                                     vp->name_len + 1, out1);
 709                                                 out1qstr(vp->text +
 710                                                     vp->name_len + 1);
 711                                         } else
 712                                                 outbin(vp->text, vp->name_len,
 713                                                     out1);
 714                                         out1c('\n');
 715                                 }
 716                         }
 717                 }
 718         }
 719         return 0;
 720 }
 721
 722
 723 /*
 724  * The "local" command.
 725  */
 726
 727 int
 728 localcmd(int argc __unused, char **argv __unused)
 729 {
 730         char *name;
 731
 732         nextopt("");
 733         if (! in_function())
 734                 error("Not in a function");
 735         while ((name = *argptr++) != NULL) {
 736                 mklocal(name);
 737         }
 738         return 0;
 739 }
 740
 741
 742 /*
 743  * Make a variable a local variable.  When a variable is made local, it's
 744  * value and flags are saved in a localvar structure.  The saved values
 745  * will be restored when the shell function returns.  We handle the name
 746  * "-" as a special case.
 747  */
 748
 749 void
 750 mklocal(char *name)
 751 {
 752         struct localvar *lvp;
 753         struct var **vpp;
 754         struct var *vp;
 755
 756         INTOFF;
 757         lvp = ckmalloc(sizeof (struct localvar));
 758         if (name[0] == '-' && name[1] == '\0') {
 759                 lvp->text = ckmalloc(sizeof optlist);
 760                 memcpy(lvp->text, optlist, sizeof optlist);
 761                 vp = NULL;
 762         } else {
 763                 vp = find_var(name, &vpp, NULL);
 764                 if (vp == NULL) {
 765                         if (strchr(name, '='))
 766                                 setvareq(savestr(name), VSTRFIXED | VNOLOCAL);
 767                         else
 768                                 setvar(name, NULL, VSTRFIXED | VNOLOCAL);
 769                         vp = *vpp;      /* the new variable */
 770                         lvp->text = NULL;
 771                         lvp->flags = VUNSET;
 772                 } else {
 773                         lvp->text = vp->text;
 774                         lvp->flags = vp->flags;
 775                         vp->flags |= VSTRFIXED|VTEXTFIXED;
 776                         if (name[vp->name_len] == '=')
 777                                 setvareq(savestr(name), VNOLOCAL);
 778                 }
 779         }
 780         lvp->vp = vp;
 781         lvp->next = localvars;
 782         localvars = lvp;
 783         INTON;
 784 }
 785
 786
 787 /*
 788  * Called after a function returns.
 789  */
 790
 791 void
 792 poplocalvars(void)
 793 {
 794         struct localvar *lvp;
 795         struct var *vp;
 796
 797         INTOFF;
 798         while ((lvp = localvars) != NULL) {
 799                 localvars = lvp->next;
 800                 vp = lvp->vp;
 801                 if (vp == NULL) {       /* $- saved */
 802                         memcpy(optlist, lvp->text, sizeof optlist);
 803                         ckfree(lvp->text);
 804                         optschanged();
 805                 } else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
 806                         (void)unsetvar(vp->text);
 807                 } else {
 808                         if ((vp->flags & VTEXTFIXED) == 0)
 809                                 ckfree(vp->text);
 810                         vp->flags = lvp->flags;
 811                         vp->text = lvp->text;
 812                 }
 813                 ckfree(lvp);
 814         }
 815         INTON;
 816 }
 817
 818
 819 int
 820 setvarcmd(int argc, char **argv)
 821 {
 822         if (argc <= 2)
 823                 return unsetcmd(argc, argv);
 824         else if (argc == 3)
 825                 setvar(argv[1], argv[2], 0);
 826         else
 827                 error("too many arguments");
 828         return 0;
 829 }
 830
 831
 832 /*
 833  * The unset builtin command.
 834  */
 835
 836 int
 837 unsetcmd(int argc __unused, char **argv __unused)
 838 {
 839         char **ap;
 840         int i;
 841         int flg_func = 0;
 842         int flg_var = 0;
 843         int ret = 0;
 844
 845         while ((i = nextopt("vf")) != '\0') {
 846                 if (i == 'f')
 847                         flg_func = 1;
 848                 else
 849                         flg_var = 1;
 850         }
 851         if (flg_func == 0 && flg_var == 0)
 852                 flg_var = 1;
 853
 854         INTOFF;
 855         for (ap = argptr; *ap ; ap++) {
 856                 if (flg_func)
 857                         ret |= unsetfunc(*ap);
 858                 if (flg_var)
 859                         ret |= unsetvar(*ap);
 860         }
 861         INTON;
 862         return ret;
 863 }
 864
 865
 866 /*
 867  * Unset the specified variable.
 868  * Called with interrupts off.
 869  */
 870
 871 int
 872 unsetvar(const char *s)
 873 {
 874         struct var **vpp;
 875         struct var *vp;
 876
 877         vp = find_var(s, &vpp, NULL);
 878         if (vp == NULL)
 879                 return (0);
 880         if (vp->flags & VREADONLY)
 881                 return (1);
 882         if (vp->text[vp->name_len + 1] != '\0')
 883                 setvar(s, "", 0);
 884         if ((vp->flags & VEXPORT) && localevar(vp->text)) {
 885                 change_env(s, 0);
 886                 setlocale(LC_ALL, "");
 887                 updatecharset();
 888         }
 889         vp->flags &= ~VEXPORT;
 890         vp->flags |= VUNSET;
 891         if ((vp->flags & VSTRFIXED) == 0) {
 892                 if ((vp->flags & VTEXTFIXED) == 0)
 893                         ckfree(vp->text);
 894                 *vpp = vp->next;
 895                 ckfree(vp);
 896         }
 897         return (0);
 898 }
 899
 900
 901
 902 /*
 903  * Returns true if the two strings specify the same variable.  The first
 904  * variable name is terminated by '='; the second may be terminated by
 905  * either '=' or '\0'.
 906  */
 907
 908 static int
 909 varequal(const char *p, const char *q)
 910 {
 911         while (*p == *q++) {
 912                 if (*p++ == '=')
 913                         return 1;
 914         }
 915         if (*p == '=' && *(q - 1) == '\0')
 916                 return 1;
 917         return 0;
 918 }
 919
 920 /*
 921  * Search for a variable.
 922  * 'name' may be terminated by '=' or a NUL.
 923  * vppp is set to the pointer to vp, or the list head if vp isn't found
 924  * lenp is set to the number of characters in 'name'
 925  */
 926
 927 static struct var *
 928 find_var(const char *name, struct var ***vppp, int *lenp)
 929 {
 930         unsigned int hashval;
 931         int len;
 932         struct var *vp, **vpp;
 933         const char *p = name;
 934
 935         hashval = 0;
 936         while (*p && *p != '=')
 937                 hashval = 2 * hashval + (unsigned char)*p++;
 938         len = p - name;
 939
 940         if (lenp)
 941                 *lenp = len;
 942         vpp = &vartab[hashval % VTABSIZE];
 943         if (vppp)
 944                 *vppp = vpp;
 945
 946         for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
 947                 if (vp->name_len != len)
 948                         continue;
 949                 if (memcmp(vp->text, name, len) != 0)
 950                         continue;
 951                 if (vppp)
 952                         *vppp = vpp;
 953                 return vp;
 954         }
 955         return NULL;
 956 }