bin/sh/expand.c

   1 /*-
   2  * Copyright (c) 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  * Copyright (c) 1997-2005
   5  *      Herbert Xu <herbert@gondor.apana.org.au>.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Kenneth Almquist.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 4. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #ifndef lint
  36 #if 0
  37 static char sccsid[] = "@(#)expand.c    8.5 (Berkeley) 5/15/95";
  38 #endif
  39 #endif /* not lint */
  40 #include <sys/cdefs.h>
  41 __FBSDID("$FreeBSD$");
  42
  43 #include <sys/types.h>
  44 #include <sys/time.h>
  45 #include <sys/stat.h>
  46 #include <errno.h>
  47 #include <dirent.h>
  48 #include <unistd.h>
  49 #include <pwd.h>
  50 #include <stdlib.h>
  51 #include <limits.h>
  52 #include <stdio.h>
  53 #include <string.h>
  54
  55 /*
  56  * Routines to expand arguments to commands.  We have to deal with
  57  * backquotes, shell variables, and file metacharacters.
  58  */
  59
  60 #include "shell.h"
  61 #include "main.h"
  62 #include "nodes.h"
  63 #include "eval.h"
  64 #include "expand.h"
  65 #include "syntax.h"
  66 #include "parser.h"
  67 #include "jobs.h"
  68 #include "options.h"
  69 #include "var.h"
  70 #include "input.h"
  71 #include "output.h"
  72 #include "memalloc.h"
  73 #include "error.h"
  74 #include "mystring.h"
  75 #include "arith.h"
  76 #include "show.h"
  77
  78 /*
  79  * Structure specifying which parts of the string should be searched
  80  * for IFS characters.
  81  */
  82
  83 struct ifsregion {
  84         struct ifsregion *next; /* next region in list */
  85         int begoff;             /* offset of start of region */
  86         int endoff;             /* offset of end of region */
  87         int inquotes;           /* search for nul bytes only */
  88 };
  89
  90
  91 STATIC char *expdest;                   /* output of current string */
  92 STATIC struct nodelist *argbackq;       /* list of back quote expressions */
  93 STATIC struct ifsregion ifsfirst;       /* first struct in list of ifs regions */
  94 STATIC struct ifsregion *ifslastp;      /* last struct in list */
  95 STATIC struct arglist exparg;           /* holds expanded arg list */
  96
  97 STATIC void argstr(char *, int);
  98 STATIC char *exptilde(char *, int);
  99 STATIC void expbackq(union node *, int, int);
 100 STATIC int subevalvar(char *, char *, int, int, int, int);
 101 STATIC char *evalvar(char *, int);
 102 STATIC int varisset(char *, int);
 103 STATIC void varvalue(char *, int, int, int);
 104 STATIC void recordregion(int, int, int);
 105 STATIC void removerecordregions(int);
 106 STATIC void ifsbreakup(char *, struct arglist *);
 107 STATIC void expandmeta(struct strlist *, int);
 108 STATIC void expmeta(char *, char *);
 109 STATIC void addfname(char *);
 110 STATIC struct strlist *expsort(struct strlist *);
 111 STATIC struct strlist *msort(struct strlist *, int);
 112 STATIC int pmatch(char *, char *, int);
 113 STATIC char *cvtnum(int, char *);
 114 STATIC int collate_range_cmp(int, int);
 115
 116 STATIC int
 117 collate_range_cmp(int c1, int c2)
 118 {
 119         static char s1[2], s2[2];
 120
 121         s1[0] = c1;
 122         s2[0] = c2;
 123         return (strcoll(s1, s2));
 124 }
 125
 126 /*
 127  * Expand shell variables and backquotes inside a here document.
 128  *      union node *arg         the document
 129  *      int fd;                 where to write the expanded version
 130  */
 131
 132 void
 133 expandhere(union node *arg, int fd)
 134 {
 135         herefd = fd;
 136         expandarg(arg, (struct arglist *)NULL, 0);
 137         xwrite(fd, stackblock(), expdest - stackblock());
 138 }
 139
 140
 141 /*
 142  * Perform variable substitution and command substitution on an argument,
 143  * placing the resulting list of arguments in arglist.  If EXP_FULL is true,
 144  * perform splitting and file name expansion.  When arglist is NULL, perform
 145  * here document expansion.
 146  */
 147
 148 void
 149 expandarg(union node *arg, struct arglist *arglist, int flag)
 150 {
 151         struct strlist *sp;
 152         char *p;
 153
 154         argbackq = arg->narg.backquote;
 155         STARTSTACKSTR(expdest);
 156         ifsfirst.next = NULL;
 157         ifslastp = NULL;
 158         argstr(arg->narg.text, flag);
 159         if (arglist == NULL) {
 160                 return;                 /* here document expanded */
 161         }
 162         STPUTC('\0', expdest);
 163         p = grabstackstr(expdest);
 164         exparg.lastp = &exparg.list;
 165         /*
 166          * TODO - EXP_REDIR
 167          */
 168         if (flag & EXP_FULL) {
 169                 ifsbreakup(p, &exparg);
 170                 *exparg.lastp = NULL;
 171                 exparg.lastp = &exparg.list;
 172                 expandmeta(exparg.list, flag);
 173         } else {
 174                 if (flag & EXP_REDIR) /*XXX - for now, just remove escapes */
 175                         rmescapes(p);
 176                 sp = (struct strlist *)stalloc(sizeof (struct strlist));
 177                 sp->text = p;
 178                 *exparg.lastp = sp;
 179                 exparg.lastp = &sp->next;
 180         }
 181         while (ifsfirst.next != NULL) {
 182                 struct ifsregion *ifsp;
 183                 INTOFF;
 184                 ifsp = ifsfirst.next->next;
 185                 ckfree(ifsfirst.next);
 186                 ifsfirst.next = ifsp;
 187                 INTON;
 188         }
 189         *exparg.lastp = NULL;
 190         if (exparg.list) {
 191                 *arglist->lastp = exparg.list;
 192                 arglist->lastp = exparg.lastp;
 193         }
 194 }
 195
 196
 197
 198 /*
 199  * Perform variable and command substitution.  If EXP_FULL is set, output CTLESC
 200  * characters to allow for further processing.  Otherwise treat
 201  * $@ like $* since no splitting will be performed.
 202  */
 203
 204 STATIC void
 205 argstr(char *p, int flag)
 206 {
 207         char c;
 208         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);  /* do CTLESC */
 209         int firsteq = 1;
 210
 211         if (*p == '~' && (flag & (EXP_TILDE | EXP_VARTILDE)))
 212                 p = exptilde(p, flag);
 213         for (;;) {
 214                 switch (c = *p++) {
 215                 case '\0':
 216                 case CTLENDVAR: /* ??? */
 217                         goto breakloop;
 218                 case CTLQUOTEMARK:
 219                         /* "$@" syntax adherence hack */
 220                         if (p[0] == CTLVAR && p[2] == '@' && p[3] == '=')
 221                                 break;
 222                         if ((flag & EXP_FULL) != 0)
 223                                 STPUTC(c, expdest);
 224                         break;
 225                 case CTLESC:
 226                         if (quotes)
 227                                 STPUTC(c, expdest);
 228                         c = *p++;
 229                         STPUTC(c, expdest);
 230                         break;
 231                 case CTLVAR:
 232                         p = evalvar(p, flag);
 233                         break;
 234                 case CTLBACKQ:
 235                 case CTLBACKQ|CTLQUOTE:
 236                         expbackq(argbackq->n, c & CTLQUOTE, flag);
 237                         argbackq = argbackq->next;
 238                         break;
 239                 case CTLENDARI:
 240                         expari(flag);
 241                         break;
 242                 case ':':
 243                 case '=':
 244                         /*
 245                          * sort of a hack - expand tildes in variable
 246                          * assignments (after the first '=' and after ':'s).
 247                          */
 248                         STPUTC(c, expdest);
 249                         if (flag & EXP_VARTILDE && *p == '~') {
 250                                 if (c == '=') {
 251                                         if (firsteq)
 252                                                 firsteq = 0;
 253                                         else
 254                                                 break;
 255                                 }
 256                                 p = exptilde(p, flag);
 257                         }
 258                         break;
 259                 default:
 260                         STPUTC(c, expdest);
 261                 }
 262         }
 263 breakloop:;
 264 }
 265
 266 STATIC char *
 267 exptilde(char *p, int flag)
 268 {
 269         char c, *startp = p;
 270         struct passwd *pw;
 271         char *home;
 272         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 273
 274         while ((c = *p) != '\0') {
 275                 switch(c) {
 276                 case CTLESC:
 277                         return (startp);
 278                 case CTLQUOTEMARK:
 279                         return (startp);
 280                 case ':':
 281                         if (flag & EXP_VARTILDE)
 282                                 goto done;
 283                         break;
 284                 case '/':
 285                         goto done;
 286                 }
 287                 p++;
 288         }
 289 done:
 290         *p = '\0';
 291         if (*(startp+1) == '\0') {
 292                 if ((home = lookupvar("HOME")) == NULL)
 293                         goto lose;
 294         } else {
 295                 if ((pw = getpwnam(startp+1)) == NULL)
 296                         goto lose;
 297                 home = pw->pw_dir;
 298         }
 299         if (*home == '\0')
 300                 goto lose;
 301         *p = c;
 302         while ((c = *home++) != '\0') {
 303                 if (quotes && SQSYNTAX[(int)c] == CCTL)
 304                         STPUTC(CTLESC, expdest);
 305                 STPUTC(c, expdest);
 306         }
 307         return (p);
 308 lose:
 309         *p = c;
 310         return (startp);
 311 }
 312
 313
 314 STATIC void
 315 removerecordregions(int endoff)
 316 {
 317         if (ifslastp == NULL)
 318                 return;
 319
 320         if (ifsfirst.endoff > endoff) {
 321                 while (ifsfirst.next != NULL) {
 322                         struct ifsregion *ifsp;
 323                         INTOFF;
 324                         ifsp = ifsfirst.next->next;
 325                         ckfree(ifsfirst.next);
 326                         ifsfirst.next = ifsp;
 327                         INTON;
 328                 }
 329                 if (ifsfirst.begoff > endoff)
 330                         ifslastp = NULL;
 331                 else {
 332                         ifslastp = &ifsfirst;
 333                         ifsfirst.endoff = endoff;
 334                 }
 335                 return;
 336         }
 337
 338         ifslastp = &ifsfirst;
 339         while (ifslastp->next && ifslastp->next->begoff < endoff)
 340                 ifslastp=ifslastp->next;
 341         while (ifslastp->next != NULL) {
 342                 struct ifsregion *ifsp;
 343                 INTOFF;
 344                 ifsp = ifslastp->next->next;
 345                 ckfree(ifslastp->next);
 346                 ifslastp->next = ifsp;
 347                 INTON;
 348         }
 349         if (ifslastp->endoff > endoff)
 350                 ifslastp->endoff = endoff;
 351 }
 352
 353 /*
 354  * Expand arithmetic expression.  Backup to start of expression,
 355  * evaluate, place result in (backed up) result, adjust string position.
 356  */
 357 void
 358 expari(int flag)
 359 {
 360         char *p, *start;
 361         arith_t result;
 362         int begoff;
 363         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 364         int quoted;
 365
 366
 367         /*
 368          * This routine is slightly over-complicated for
 369          * efficiency.  First we make sure there is
 370          * enough space for the result, which may be bigger
 371          * than the expression if we add exponentiation.  Next we
 372          * scan backwards looking for the start of arithmetic.  If the
 373          * next previous character is a CTLESC character, then we
 374          * have to rescan starting from the beginning since CTLESC
 375          * characters have to be processed left to right.
 376          */
 377         CHECKSTRSPACE(DIGITS(result) - 2, expdest);
 378         USTPUTC('\0', expdest);
 379         start = stackblock();
 380         p = expdest - 2;
 381         while (p >= start && *p != CTLARI)
 382                 --p;
 383         if (p < start || *p != CTLARI)
 384                 error("missing CTLARI (shouldn't happen)");
 385         if (p > start && *(p - 1) == CTLESC)
 386                 for (p = start; *p != CTLARI; p++)
 387                         if (*p == CTLESC)
 388                                 p++;
 389
 390         if (p[1] == '"')
 391                 quoted=1;
 392         else
 393                 quoted=0;
 394         begoff = p - start;
 395         removerecordregions(begoff);
 396         if (quotes)
 397                 rmescapes(p+2);
 398         result = arith(p+2);
 399         fmtstr(p, DIGITS(result), ARITH_FORMAT_STR, result);
 400         while (*p++)
 401                 ;
 402         if (quoted == 0)
 403                 recordregion(begoff, p - 1 - start, 0);
 404         result = expdest - p + 1;
 405         STADJUST(-result, expdest);
 406 }
 407
 408
 409 /*
 410  * Expand stuff in backwards quotes.
 411  */
 412
 413 STATIC void
 414 expbackq(union node *cmd, int quoted, int flag)
 415 {
 416         struct backcmd in;
 417         int i;
 418         char buf[128];
 419         char *p;
 420         char *dest = expdest;
 421         struct ifsregion saveifs, *savelastp;
 422         struct nodelist *saveargbackq;
 423         char lastc;
 424         int startloc = dest - stackblock();
 425         char const *syntax = quoted? DQSYNTAX : BASESYNTAX;
 426         int saveherefd;
 427         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 428         int nnl;
 429
 430         INTOFF;
 431         saveifs = ifsfirst;
 432         savelastp = ifslastp;
 433         saveargbackq = argbackq;
 434         saveherefd = herefd;
 435         herefd = -1;
 436         p = grabstackstr(dest);
 437         evalbackcmd(cmd, &in);
 438         ungrabstackstr(p, dest);
 439         ifsfirst = saveifs;
 440         ifslastp = savelastp;
 441         argbackq = saveargbackq;
 442         herefd = saveherefd;
 443
 444         p = in.buf;
 445         lastc = '\0';
 446         nnl = 0;
 447         /* Don't copy trailing newlines */
 448         for (;;) {
 449                 if (--in.nleft < 0) {
 450                         if (in.fd < 0)
 451                                 break;
 452                         while ((i = read(in.fd, buf, sizeof buf)) < 0 && errno == EINTR);
 453                         TRACE(("expbackq: read returns %d\n", i));
 454                         if (i <= 0)
 455                                 break;
 456                         p = buf;
 457                         in.nleft = i - 1;
 458                 }
 459                 lastc = *p++;
 460                 if (lastc != '\0') {
 461                         if (quotes && syntax[(int)lastc] == CCTL)
 462                                 STPUTC(CTLESC, dest);
 463                         if (lastc == '\n') {
 464                                 nnl++;
 465                         } else {
 466                                 while (nnl > 0) {
 467                                         nnl--;
 468                                         STPUTC('\n', dest);
 469                                 }
 470                                 STPUTC(lastc, dest);
 471                         }
 472                 }
 473         }
 474
 475         if (in.fd >= 0)
 476                 close(in.fd);
 477         if (in.buf)
 478                 ckfree(in.buf);
 479         if (in.jp)
 480                 exitstatus = waitforjob(in.jp, (int *)NULL);
 481         if (quoted == 0)
 482                 recordregion(startloc, dest - stackblock(), 0);
 483         TRACE(("evalbackq: size=%d: \"%.*s\"\n",
 484                 (dest - stackblock()) - startloc,
 485                 (dest - stackblock()) - startloc,
 486                 stackblock() + startloc));
 487         expdest = dest;
 488         INTON;
 489 }
 490
 491
 492
 493 STATIC int
 494 subevalvar(char *p, char *str, int strloc, int subtype, int startloc,
 495   int varflags)
 496 {
 497         char *startp;
 498         char *loc = NULL;
 499         char *q;
 500         int c = 0;
 501         int saveherefd = herefd;
 502         struct nodelist *saveargbackq = argbackq;
 503         int amount;
 504
 505         herefd = -1;
 506         argstr(p, 0);
 507         STACKSTRNUL(expdest);
 508         herefd = saveherefd;
 509         argbackq = saveargbackq;
 510         startp = stackblock() + startloc;
 511         if (str == NULL)
 512             str = stackblock() + strloc;
 513
 514         switch (subtype) {
 515         case VSASSIGN:
 516                 setvar(str, startp, 0);
 517                 amount = startp - expdest;
 518                 STADJUST(amount, expdest);
 519                 varflags &= ~VSNUL;
 520                 if (c != 0)
 521                         *loc = c;
 522                 return 1;
 523
 524         case VSQUESTION:
 525                 if (*p != CTLENDVAR) {
 526                         outfmt(&errout, "%s\n", startp);
 527                         error((char *)NULL);
 528                 }
 529                 error("%.*s: parameter %snot set", (int)(p - str - 1),
 530                       str, (varflags & VSNUL) ? "null or "
 531                                               : nullstr);
 532                 return 0;
 533
 534         case VSTRIMLEFT:
 535                 for (loc = startp; loc < str; loc++) {
 536                         c = *loc;
 537                         *loc = '\0';
 538                         if (patmatch(str, startp, varflags & VSQUOTE)) {
 539                                 *loc = c;
 540                                 goto recordleft;
 541                         }
 542                         *loc = c;
 543                         if ((varflags & VSQUOTE) && *loc == CTLESC)
 544                                 loc++;
 545                 }
 546                 return 0;
 547
 548         case VSTRIMLEFTMAX:
 549                 for (loc = str - 1; loc >= startp;) {
 550                         c = *loc;
 551                         *loc = '\0';
 552                         if (patmatch(str, startp, varflags & VSQUOTE)) {
 553                                 *loc = c;
 554                                 goto recordleft;
 555                         }
 556                         *loc = c;
 557                         loc--;
 558                         if ((varflags & VSQUOTE) && loc > startp &&
 559                             *(loc - 1) == CTLESC) {
 560                                 for (q = startp; q < loc; q++)
 561                                         if (*q == CTLESC)
 562                                                 q++;
 563                                 if (q > loc)
 564                                         loc--;
 565                         }
 566                 }
 567                 return 0;
 568
 569         case VSTRIMRIGHT:
 570                 for (loc = str - 1; loc >= startp;) {
 571                         if (patmatch(str, loc, varflags & VSQUOTE)) {
 572                                 amount = loc - expdest;
 573                                 STADJUST(amount, expdest);
 574                                 return 1;
 575                         }
 576                         loc--;
 577                         if ((varflags & VSQUOTE) && loc > startp &&
 578                             *(loc - 1) == CTLESC) {
 579                                 for (q = startp; q < loc; q++)
 580                                         if (*q == CTLESC)
 581                                                 q++;
 582                                 if (q > loc)
 583                                         loc--;
 584                         }
 585                 }
 586                 return 0;
 587
 588         case VSTRIMRIGHTMAX:
 589                 for (loc = startp; loc < str - 1; loc++) {
 590                         if (patmatch(str, loc, varflags & VSQUOTE)) {
 591                                 amount = loc - expdest;
 592                                 STADJUST(amount, expdest);
 593                                 return 1;
 594                         }
 595                         if ((varflags & VSQUOTE) && *loc == CTLESC)
 596                                 loc++;
 597                 }
 598                 return 0;
 599
 600
 601         default:
 602                 abort();
 603         }
 604
 605 recordleft:
 606         amount = ((str - 1) - (loc - startp)) - expdest;
 607         STADJUST(amount, expdest);
 608         while (loc != str - 1)
 609                 *startp++ = *loc++;
 610         return 1;
 611 }
 612
 613
 614 /*
 615  * Expand a variable, and return a pointer to the next character in the
 616  * input string.
 617  */
 618
 619 STATIC char *
 620 evalvar(char *p, int flag)
 621 {
 622         int subtype;
 623         int varflags;
 624         char *var;
 625         char *val;
 626         int patloc;
 627         int c;
 628         int set;
 629         int special;
 630         int startloc;
 631         int varlen;
 632         int easy;
 633         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 634
 635         varflags = (unsigned char)*p++;
 636         subtype = varflags & VSTYPE;
 637         var = p;
 638         special = 0;
 639         if (! is_name(*p))
 640                 special = 1;
 641         p = strchr(p, '=') + 1;
 642 again: /* jump here after setting a variable with ${var=text} */
 643         if (varflags & VSLINENO) {
 644                 set = 1;
 645                 special = 0;
 646                 val = var;
 647                 p[-1] = '\0';   /* temporarily overwrite '=' to have \0
 648                                    terminated string */
 649         } else if (special) {
 650                 set = varisset(var, varflags & VSNUL);
 651                 val = NULL;
 652         } else {
 653                 val = bltinlookup(var, 1);
 654                 if (val == NULL || ((varflags & VSNUL) && val[0] == '\0')) {
 655                         val = NULL;
 656                         set = 0;
 657                 } else
 658                         set = 1;
 659         }
 660         varlen = 0;
 661         startloc = expdest - stackblock();
 662         if (!set && uflag) {
 663                 switch (subtype) {
 664                 case VSNORMAL:
 665                 case VSTRIMLEFT:
 666                 case VSTRIMLEFTMAX:
 667                 case VSTRIMRIGHT:
 668                 case VSTRIMRIGHTMAX:
 669                 case VSLENGTH:
 670                         error("%.*s: parameter not set", (int)(p - var - 1),
 671                             var);
 672                 }
 673         }
 674         if (set && subtype != VSPLUS) {
 675                 /* insert the value of the variable */
 676                 if (special) {
 677                         varvalue(var, varflags & VSQUOTE, subtype, flag);
 678                         if (subtype == VSLENGTH) {
 679                                 varlen = expdest - stackblock() - startloc;
 680                                 STADJUST(-varlen, expdest);
 681                         }
 682                 } else {
 683                         char const *syntax = (varflags & VSQUOTE) ? DQSYNTAX
 684                                                                   : BASESYNTAX;
 685
 686                         if (subtype == VSLENGTH) {
 687                                 for (;*val; val++)
 688                                         varlen++;
 689                         }
 690                         else {
 691                                 while (*val) {
 692                                         if (quotes &&
 693                                             syntax[(int)*val] == CCTL)
 694                                                 STPUTC(CTLESC, expdest);
 695                                         STPUTC(*val++, expdest);
 696                                 }
 697
 698                         }
 699                 }
 700         }
 701
 702         if (subtype == VSPLUS)
 703                 set = ! set;
 704
 705         easy = ((varflags & VSQUOTE) == 0 ||
 706                 (*var == '@' && shellparam.nparam != 1));
 707
 708
 709         switch (subtype) {
 710         case VSLENGTH:
 711                 expdest = cvtnum(varlen, expdest);
 712                 goto record;
 713
 714         case VSNORMAL:
 715                 if (!easy)
 716                         break;
 717 record:
 718                 recordregion(startloc, expdest - stackblock(),
 719                              varflags & VSQUOTE);
 720                 break;
 721
 722         case VSPLUS:
 723         case VSMINUS:
 724                 if (!set) {
 725                         argstr(p, flag);
 726                         break;
 727                 }
 728                 if (easy)
 729                         goto record;
 730                 break;
 731
 732         case VSTRIMLEFT:
 733         case VSTRIMLEFTMAX:
 734         case VSTRIMRIGHT:
 735         case VSTRIMRIGHTMAX:
 736                 if (!set)
 737                         break;
 738                 /*
 739                  * Terminate the string and start recording the pattern
 740                  * right after it
 741                  */
 742                 STPUTC('\0', expdest);
 743                 patloc = expdest - stackblock();
 744                 if (subevalvar(p, NULL, patloc, subtype,
 745                                startloc, varflags) == 0) {
 746                         int amount = (expdest - stackblock() - patloc) + 1;
 747                         STADJUST(-amount, expdest);
 748                 }
 749                 /* Remove any recorded regions beyond start of variable */
 750                 removerecordregions(startloc);
 751                 goto record;
 752
 753         case VSASSIGN:
 754         case VSQUESTION:
 755                 if (!set) {
 756                         if (subevalvar(p, var, 0, subtype, startloc, varflags)) {
 757                                 varflags &= ~VSNUL;
 758                                 /*
 759                                  * Remove any recorded regions beyond
 760                                  * start of variable
 761                                  */
 762                                 removerecordregions(startloc);
 763                                 goto again;
 764                         }
 765                         break;
 766                 }
 767                 if (easy)
 768                         goto record;
 769                 break;
 770
 771         case VSERROR:
 772                 c = p - var - 1;
 773                 error("${%.*s%s}: Bad substitution", c, var,
 774                     (c > 0 && *p != CTLENDVAR) ? "..." : "");
 775
 776         default:
 777                 abort();
 778         }
 779         p[-1] = '=';    /* recover overwritten '=' */
 780
 781         if (subtype != VSNORMAL) {      /* skip to end of alternative */
 782                 int nesting = 1;
 783                 for (;;) {
 784                         if ((c = *p++) == CTLESC)
 785                                 p++;
 786                         else if (c == CTLBACKQ || c == (CTLBACKQ|CTLQUOTE)) {
 787                                 if (set)
 788                                         argbackq = argbackq->next;
 789                         } else if (c == CTLVAR) {
 790                                 if ((*p++ & VSTYPE) != VSNORMAL)
 791                                         nesting++;
 792                         } else if (c == CTLENDVAR) {
 793                                 if (--nesting == 0)
 794                                         break;
 795                         }
 796                 }
 797         }
 798         return p;
 799 }
 800
 801
 802
 803 /*
 804  * Test whether a specialized variable is set.
 805  */
 806
 807 STATIC int
 808 varisset(char *name, int nulok)
 809 {
 810
 811         if (*name == '!')
 812                 return backgndpid != -1;
 813         else if (*name == '@' || *name == '*') {
 814                 if (*shellparam.p == NULL)
 815                         return 0;
 816
 817                 if (nulok) {
 818                         char **av;
 819
 820                         for (av = shellparam.p; *av; av++)
 821                                 if (**av != '\0')
 822                                         return 1;
 823                         return 0;
 824                 }
 825         } else if (is_digit(*name)) {
 826                 char *ap;
 827                 int num = atoi(name);
 828
 829                 if (num > shellparam.nparam)
 830                         return 0;
 831
 832                 if (num == 0)
 833                         ap = arg0;
 834                 else
 835                         ap = shellparam.p[num - 1];
 836
 837                 if (nulok && (ap == NULL || *ap == '\0'))
 838                         return 0;
 839         }
 840         return 1;
 841 }
 842
 843
 844
 845 /*
 846  * Add the value of a specialized variable to the stack string.
 847  */
 848
 849 STATIC void
 850 varvalue(char *name, int quoted, int subtype, int flag)
 851 {
 852         int num;
 853         char *p;
 854         int i;
 855         extern int oexitstatus;
 856         char sep;
 857         char **ap;
 858         char const *syntax;
 859
 860 #define STRTODEST(p) \
 861         do {\
 862         if (flag & (EXP_FULL | EXP_CASE) && subtype != VSLENGTH) { \
 863                 syntax = quoted? DQSYNTAX : BASESYNTAX; \
 864                 while (*p) { \
 865                         if (syntax[(int)*p] == CCTL) \
 866                                 STPUTC(CTLESC, expdest); \
 867                         STPUTC(*p++, expdest); \
 868                 } \
 869         } else \
 870                 while (*p) \
 871                         STPUTC(*p++, expdest); \
 872         } while (0)
 873
 874
 875         switch (*name) {
 876         case '$':
 877                 num = rootpid;
 878                 goto numvar;
 879         case '?':
 880                 num = oexitstatus;
 881                 goto numvar;
 882         case '#':
 883                 num = shellparam.nparam;
 884                 goto numvar;
 885         case '!':
 886                 num = backgndpid;
 887 numvar:
 888                 expdest = cvtnum(num, expdest);
 889                 break;
 890         case '-':
 891                 for (i = 0 ; i < NOPTS ; i++) {
 892                         if (optlist[i].val)
 893                                 STPUTC(optlist[i].letter, expdest);
 894                 }
 895                 break;
 896         case '@':
 897                 if (flag & EXP_FULL && quoted) {
 898                         for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
 899                                 STRTODEST(p);
 900                                 if (*ap)
 901                                         STPUTC('\0', expdest);
 902                         }
 903                         break;
 904                 }
 905                 /* FALLTHROUGH */
 906         case '*':
 907                 if (ifsset())
 908                         sep = ifsval()[0];
 909                 else
 910                         sep = ' ';
 911                 for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
 912                         STRTODEST(p);
 913                         if (*ap && sep)
 914                                 STPUTC(sep, expdest);
 915                 }
 916                 break;
 917         case '0':
 918                 p = arg0;
 919                 STRTODEST(p);
 920                 break;
 921         default:
 922                 if (is_digit(*name)) {
 923                         num = atoi(name);
 924                         if (num > 0 && num <= shellparam.nparam) {
 925                                 p = shellparam.p[num - 1];
 926                                 STRTODEST(p);
 927                         }
 928                 }
 929                 break;
 930         }
 931 }
 932
 933
 934
 935 /*
 936  * Record the the fact that we have to scan this region of the
 937  * string for IFS characters.
 938  */
 939
 940 STATIC void
 941 recordregion(int start, int end, int inquotes)
 942 {
 943         struct ifsregion *ifsp;
 944
 945         if (ifslastp == NULL) {
 946                 ifsp = &ifsfirst;
 947         } else {
 948                 if (ifslastp->endoff == start
 949                     && ifslastp->inquotes == inquotes) {
 950                         /* extend previous area */
 951                         ifslastp->endoff = end;
 952                         return;
 953                 }
 954                 ifsp = (struct ifsregion *)ckmalloc(sizeof (struct ifsregion));
 955                 ifslastp->next = ifsp;
 956         }
 957         ifslastp = ifsp;
 958         ifslastp->next = NULL;
 959         ifslastp->begoff = start;
 960         ifslastp->endoff = end;
 961         ifslastp->inquotes = inquotes;
 962 }
 963
 964
 965
 966 /*
 967  * Break the argument string into pieces based upon IFS and add the
 968  * strings to the argument list.  The regions of the string to be
 969  * searched for IFS characters have been stored by recordregion.
 970  */
 971 STATIC void
 972 ifsbreakup(char *string, struct arglist *arglist)
 973 {
 974         struct ifsregion *ifsp;
 975         struct strlist *sp;
 976         char *start;
 977         char *p;
 978         char *q;
 979         char *ifs;
 980         const char *ifsspc;
 981         int had_param_ch = 0;
 982
 983         start = string;
 984
 985         if (ifslastp == NULL) {
 986                 /* Return entire argument, IFS doesn't apply to any of it */
 987                 sp = (struct strlist *)stalloc(sizeof *sp);
 988                 sp->text = start;
 989                 *arglist->lastp = sp;
 990                 arglist->lastp = &sp->next;
 991                 return;
 992         }
 993
 994         ifs = ifsset() ? ifsval() : " \t\n";
 995
 996         for (ifsp = &ifsfirst; ifsp != NULL; ifsp = ifsp->next) {
 997                 p = string + ifsp->begoff;
 998                 while (p < string + ifsp->endoff) {
 999                         q = p;
1000                         if (*p == CTLESC)
1001                                 p++;
1002                         if (ifsp->inquotes) {
1003                                 /* Only NULs (should be from "$@") end args */
1004                                 had_param_ch = 1;
1005                                 if (*p != 0) {
1006                                         p++;
1007                                         continue;
1008                                 }
1009                                 ifsspc = NULL;
1010                         } else {
1011                                 if (!strchr(ifs, *p)) {
1012                                         had_param_ch = 1;
1013                                         p++;
1014                                         continue;
1015                                 }
1016                                 ifsspc = strchr(" \t\n", *p);
1017
1018                                 /* Ignore IFS whitespace at start */
1019                                 if (q == start && ifsspc != NULL) {
1020                                         p++;
1021                                         start = p;
1022                                         continue;
1023                                 }
1024                                 had_param_ch = 0;
1025                         }
1026
1027                         /* Save this argument... */
1028                         *q = '\0';
1029                         sp = (struct strlist *)stalloc(sizeof *sp);
1030                         sp->text = start;
1031                         *arglist->lastp = sp;
1032                         arglist->lastp = &sp->next;
1033                         p++;
1034
1035                         if (ifsspc != NULL) {
1036                                 /* Ignore further trailing IFS whitespace */
1037                                 for (; p < string + ifsp->endoff; p++) {
1038                                         q = p;
1039                                         if (*p == CTLESC)
1040                                                 p++;
1041                                         if (strchr(ifs, *p) == NULL) {
1042                                                 p = q;
1043                                                 break;
1044                                         }
1045                                         if (strchr(" \t\n", *p) == NULL) {
1046                                                 p++;
1047                                                 break;
1048                                         }
1049                                 }
1050                         }
1051                         start = p;
1052                 }
1053         }
1054
1055         /*
1056          * Save anything left as an argument.
1057          * Traditionally we have treated 'IFS=':'; set -- x$IFS' as
1058          * generating 2 arguments, the second of which is empty.
1059          * Some recent clarification of the Posix spec say that it
1060          * should only generate one....
1061          */
1062         if (had_param_ch || *start != 0) {
1063                 sp = (struct strlist *)stalloc(sizeof *sp);
1064                 sp->text = start;
1065                 *arglist->lastp = sp;
1066                 arglist->lastp = &sp->next;
1067         }
1068 }
1069
1070
1071
1072 /*
1073  * Expand shell metacharacters.  At this point, the only control characters
1074  * should be escapes.  The results are stored in the list exparg.
1075  */
1076
1077 STATIC char *expdir;
1078
1079
1080 STATIC void
1081 expandmeta(struct strlist *str, int flag __unused)
1082 {
1083         char *p;
1084         struct strlist **savelastp;
1085         struct strlist *sp;
1086         char c;
1087         /* TODO - EXP_REDIR */
1088
1089         while (str) {
1090                 if (fflag)
1091                         goto nometa;
1092                 p = str->text;
1093                 for (;;) {                      /* fast check for meta chars */
1094                         if ((c = *p++) == '\0')
1095                                 goto nometa;
1096                         if (c == '*' || c == '?' || c == '[' || c == '!')
1097                                 break;
1098                 }
1099                 savelastp = exparg.lastp;
1100                 INTOFF;
1101                 if (expdir == NULL) {
1102                         int i = strlen(str->text);
1103                         expdir = ckmalloc(i < 2048 ? 2048 : i); /* XXX */
1104                 }
1105
1106                 expmeta(expdir, str->text);
1107                 ckfree(expdir);
1108                 expdir = NULL;
1109                 INTON;
1110                 if (exparg.lastp == savelastp) {
1111                         /*
1112                          * no matches
1113                          */
1114 nometa:
1115                         *exparg.lastp = str;
1116                         rmescapes(str->text);
1117                         exparg.lastp = &str->next;
1118                 } else {
1119                         *exparg.lastp = NULL;
1120                         *savelastp = sp = expsort(*savelastp);
1121                         while (sp->next != NULL)
1122                                 sp = sp->next;
1123                         exparg.lastp = &sp->next;
1124                 }
1125                 str = str->next;
1126         }
1127 }
1128
1129
1130 /*
1131  * Do metacharacter (i.e. *, ?, [...]) expansion.
1132  */
1133
1134 STATIC void
1135 expmeta(char *enddir, char *name)
1136 {
1137         char *p;
1138         char *q;
1139         char *start;
1140         char *endname;
1141         int metaflag;
1142         struct stat statb;
1143         DIR *dirp;
1144         struct dirent *dp;
1145         int atend;
1146         int matchdot;
1147         int esc;
1148
1149         metaflag = 0;
1150         start = name;
1151         for (p = name; esc = 0, *p; p += esc + 1) {
1152                 if (*p == '*' || *p == '?')
1153                         metaflag = 1;
1154                 else if (*p == '[') {
1155                         q = p + 1;
1156                         if (*q == '!' || *q == '^')
1157                                 q++;
1158                         for (;;) {
1159                                 while (*q == CTLQUOTEMARK)
1160                                         q++;
1161                                 if (*q == CTLESC)
1162                                         q++;
1163                                 if (*q == '/' || *q == '\0')
1164                                         break;
1165                                 if (*++q == ']') {
1166                                         metaflag = 1;
1167                                         break;
1168                                 }
1169                         }
1170                 } else if (*p == '!' && p[1] == '!'     && (p == name || p[-1] == '/')) {
1171                         metaflag = 1;
1172                 } else if (*p == '\0')
1173                         break;
1174                 else if (*p == CTLQUOTEMARK)
1175                         continue;
1176                 else {
1177                         if (*p == CTLESC)
1178                                 esc++;
1179                         if (p[esc] == '/') {
1180                                 if (metaflag)
1181                                         break;
1182                                 start = p + esc + 1;
1183                         }
1184                 }
1185         }
1186         if (metaflag == 0) {    /* we've reached the end of the file name */
1187                 if (enddir != expdir)
1188                         metaflag++;
1189                 for (p = name ; ; p++) {
1190                         if (*p == CTLQUOTEMARK)
1191                                 continue;
1192                         if (*p == CTLESC)
1193                                 p++;
1194                         *enddir++ = *p;
1195                         if (*p == '\0')
1196                                 break;
1197                 }
1198                 if (metaflag == 0 || lstat(expdir, &statb) >= 0)
1199                         addfname(expdir);
1200                 return;
1201         }
1202         endname = p;
1203         if (start != name) {
1204                 p = name;
1205                 while (p < start) {
1206                         while (*p == CTLQUOTEMARK)
1207                                 p++;
1208                         if (*p == CTLESC)
1209                                 p++;
1210                         *enddir++ = *p++;
1211                 }
1212         }
1213         if (enddir == expdir) {
1214                 p = ".";
1215         } else if (enddir == expdir + 1 && *expdir == '/') {
1216                 p = "/";
1217         } else {
1218                 p = expdir;
1219                 enddir[-1] = '\0';
1220         }
1221         if ((dirp = opendir(p)) == NULL)
1222                 return;
1223         if (enddir != expdir)
1224                 enddir[-1] = '/';
1225         if (*endname == 0) {
1226                 atend = 1;
1227         } else {
1228                 atend = 0;
1229                 *endname = '\0';
1230                 endname += esc + 1;
1231         }
1232         matchdot = 0;
1233         p = start;
1234         while (*p == CTLQUOTEMARK)
1235                 p++;
1236         if (*p == CTLESC)
1237                 p++;
1238         if (*p == '.')
1239                 matchdot++;
1240         while (! int_pending() && (dp = readdir(dirp)) != NULL) {
1241                 if (dp->d_name[0] == '.' && ! matchdot)
1242                         continue;
1243                 if (patmatch(start, dp->d_name, 0)) {
1244                         if (atend) {
1245                                 scopy(dp->d_name, enddir);
1246                                 addfname(expdir);
1247                         } else {
1248                                 for (p = enddir, q = dp->d_name;
1249                                      (*p++ = *q++) != '\0';)
1250                                         continue;
1251                                 p[-1] = '/';
1252                                 expmeta(p, endname);
1253                         }
1254                 }
1255         }
1256         closedir(dirp);
1257         if (! atend)
1258                 endname[-esc - 1] = esc ? CTLESC : '/';
1259 }
1260
1261
1262 /*
1263  * Add a file name to the list.
1264  */
1265
1266 STATIC void
1267 addfname(char *name)
1268 {
1269         char *p;
1270         struct strlist *sp;
1271
1272         p = stalloc(strlen(name) + 1);
1273         scopy(name, p);
1274         sp = (struct strlist *)stalloc(sizeof *sp);
1275         sp->text = p;
1276         *exparg.lastp = sp;
1277         exparg.lastp = &sp->next;
1278 }
1279
1280
1281 /*
1282  * Sort the results of file name expansion.  It calculates the number of
1283  * strings to sort and then calls msort (short for merge sort) to do the
1284  * work.
1285  */
1286
1287 STATIC struct strlist *
1288 expsort(struct strlist *str)
1289 {
1290         int len;
1291         struct strlist *sp;
1292
1293         len = 0;
1294         for (sp = str ; sp ; sp = sp->next)
1295                 len++;
1296         return msort(str, len);
1297 }
1298
1299
1300 STATIC struct strlist *
1301 msort(struct strlist *list, int len)
1302 {
1303         struct strlist *p, *q = NULL;
1304         struct strlist **lpp;
1305         int half;
1306         int n;
1307
1308         if (len <= 1)
1309                 return list;
1310         half = len >> 1;
1311         p = list;
1312         for (n = half ; --n >= 0 ; ) {
1313                 q = p;
1314                 p = p->next;
1315         }
1316         q->next = NULL;                 /* terminate first half of list */
1317         q = msort(list, half);          /* sort first half of list */
1318         p = msort(p, len - half);               /* sort second half */
1319         lpp = &list;
1320         for (;;) {
1321                 if (strcmp(p->text, q->text) < 0) {
1322                         *lpp = p;
1323                         lpp = &p->next;
1324                         if ((p = *lpp) == NULL) {
1325                                 *lpp = q;
1326                                 break;
1327                         }
1328                 } else {
1329                         *lpp = q;
1330                         lpp = &q->next;
1331                         if ((q = *lpp) == NULL) {
1332                                 *lpp = p;
1333                                 break;
1334                         }
1335                 }
1336         }
1337         return list;
1338 }
1339
1340
1341
1342 /*
1343  * Returns true if the pattern matches the string.
1344  */
1345
1346 int
1347 patmatch(char *pattern, char *string, int squoted)
1348 {
1349 #ifdef notdef
1350         if (pattern[0] == '!' && pattern[1] == '!')
1351                 return 1 - pmatch(pattern + 2, string);
1352         else
1353 #endif
1354                 return pmatch(pattern, string, squoted);
1355 }
1356
1357
1358 STATIC int
1359 pmatch(char *pattern, char *string, int squoted)
1360 {
1361         char *p, *q;
1362         char c;
1363
1364         p = pattern;
1365         q = string;
1366         for (;;) {
1367                 switch (c = *p++) {
1368                 case '\0':
1369                         goto breakloop;
1370                 case CTLESC:
1371                         if (squoted && *q == CTLESC)
1372                                 q++;
1373                         if (*q++ != *p++)
1374                                 return 0;
1375                         break;
1376                 case CTLQUOTEMARK:
1377                         continue;
1378                 case '?':
1379                         if (squoted && *q == CTLESC)
1380                                 q++;
1381                         if (*q++ == '\0')
1382                                 return 0;
1383                         break;
1384                 case '*':
1385                         c = *p;
1386                         while (c == CTLQUOTEMARK || c == '*')
1387                                 c = *++p;
1388                         if (c != CTLESC &&  c != CTLQUOTEMARK &&
1389                             c != '?' && c != '*' && c != '[') {
1390                                 while (*q != c) {
1391                                         if (squoted && *q == CTLESC &&
1392                                             q[1] == c)
1393                                                 break;
1394                                         if (*q == '\0')
1395                                                 return 0;
1396                                         if (squoted && *q == CTLESC)
1397                                                 q++;
1398                                         q++;
1399                                 }
1400                         }
1401                         do {
1402                                 if (pmatch(p, q, squoted))
1403                                         return 1;
1404                                 if (squoted && *q == CTLESC)
1405                                         q++;
1406                         } while (*q++ != '\0');
1407                         return 0;
1408                 case '[': {
1409                         char *endp;
1410                         int invert, found;
1411                         char chr;
1412
1413                         endp = p;
1414                         if (*endp == '!' || *endp == '^')
1415                                 endp++;
1416                         for (;;) {
1417                                 while (*endp == CTLQUOTEMARK)
1418                                         endp++;
1419                                 if (*endp == '\0')
1420                                         goto dft;               /* no matching ] */
1421                                 if (*endp == CTLESC)
1422                                         endp++;
1423                                 if (*++endp == ']')
1424                                         break;
1425                         }
1426                         invert = 0;
1427                         if (*p == '!' || *p == '^') {
1428                                 invert++;
1429                                 p++;
1430                         }
1431                         found = 0;
1432                         chr = *q++;
1433                         if (squoted && chr == CTLESC)
1434                                 chr = *q++;
1435                         if (chr == '\0')
1436                                 return 0;
1437                         c = *p++;
1438                         do {
1439                                 if (c == CTLQUOTEMARK)
1440                                         continue;
1441                                 if (c == CTLESC)
1442                                         c = *p++;
1443                                 if (*p == '-' && p[1] != ']') {
1444                                         p++;
1445                                         while (*p == CTLQUOTEMARK)
1446                                                 p++;
1447                                         if (*p == CTLESC)
1448                                                 p++;
1449                                         if (   collate_range_cmp(chr, c) >= 0
1450                                             && collate_range_cmp(chr, *p) <= 0
1451                                            )
1452                                                 found = 1;
1453                                         p++;
1454                                 } else {
1455                                         if (chr == c)
1456                                                 found = 1;
1457                                 }
1458                         } while ((c = *p++) != ']');
1459                         if (found == invert)
1460                                 return 0;
1461                         break;
1462                 }
1463 dft:            default:
1464                         if (squoted && *q == CTLESC)
1465                                 q++;
1466                         if (*q++ != c)
1467                                 return 0;
1468                         break;
1469                 }
1470         }
1471 breakloop:
1472         if (*q != '\0')
1473                 return 0;
1474         return 1;
1475 }
1476
1477
1478
1479 /*
1480  * Remove any CTLESC characters from a string.
1481  */
1482
1483 void
1484 rmescapes(char *str)
1485 {
1486         char *p, *q;
1487
1488         p = str;
1489         while (*p != CTLESC && *p != CTLQUOTEMARK) {
1490                 if (*p++ == '\0')
1491                         return;
1492         }
1493         q = p;
1494         while (*p) {
1495                 if (*p == CTLQUOTEMARK) {
1496                         p++;
1497                         continue;
1498                 }
1499                 if (*p == CTLESC)
1500                         p++;
1501                 *q++ = *p++;
1502         }
1503         *q = '\0';
1504 }
1505
1506
1507
1508 /*
1509  * See if a pattern matches in a case statement.
1510  */
1511
1512 int
1513 casematch(union node *pattern, char *val)
1514 {
1515         struct stackmark smark;
1516         int result;
1517         char *p;
1518
1519         setstackmark(&smark);
1520         argbackq = pattern->narg.backquote;
1521         STARTSTACKSTR(expdest);
1522         ifslastp = NULL;
1523         argstr(pattern->narg.text, EXP_TILDE | EXP_CASE);
1524         STPUTC('\0', expdest);
1525         p = grabstackstr(expdest);
1526         result = patmatch(p, val, 0);
1527         popstackmark(&smark);
1528         return result;
1529 }
1530
1531 /*
1532  * Our own itoa().
1533  */
1534
1535 STATIC char *
1536 cvtnum(int num, char *buf)
1537 {
1538         char temp[32];
1539         int neg = num < 0;
1540         char *p = temp + 31;
1541
1542         temp[31] = '\0';
1543
1544         do {
1545                 *--p = num % 10 + '0';
1546         } while ((num /= 10) != 0);
1547
1548         if (neg)
1549                 *--p = '-';
1550
1551         while (*p)
1552                 STPUTC(*p++, buf);
1553         return buf;
1554 }
1555
1556 /*
1557  * Do most of the work for wordexp(3).
1558  */
1559
1560 int
1561 wordexpcmd(int argc, char **argv)
1562 {
1563         size_t len;
1564         int i;
1565
1566         out1fmt("%08x", argc - 1);
1567         for (i = 1, len = 0; i < argc; i++)
1568                 len += strlen(argv[i]);
1569         out1fmt("%08x", (int)len);
1570         for (i = 1; i < argc; i++) {
1571                 out1str(argv[i]);
1572                 out1c('\0');
1573         }
1574         return (0);
1575 }