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(const char *, const 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 expansions on an argument, placing the resulting list of arguments
 143  * in arglist.  Parameter expansion, command substitution and arithmetic
 144  * expansion are always performed; additional expansions can be requested
 145  * via flag (EXP_*).
 146  * The result is left in the stack string.
 147  * When arglist is NULL, perform here document expansion.  A partial result
 148  * may be written to herefd, which is then not included in the stack string.
 149  *
 150  * Caution: this function uses global state and is not reentrant.
 151  * However, a new invocation after an interrupted invocation is safe
 152  * and will reset the global state for the new call.
 153  */
 154 void
 155 expandarg(union node *arg, struct arglist *arglist, int flag)
 156 {
 157         struct strlist *sp;
 158         char *p;
 159
 160         argbackq = arg->narg.backquote;
 161         STARTSTACKSTR(expdest);
 162         ifsfirst.next = NULL;
 163         ifslastp = NULL;
 164         argstr(arg->narg.text, flag);
 165         if (arglist == NULL) {
 166                 return;                 /* here document expanded */
 167         }
 168         STPUTC('\0', expdest);
 169         p = grabstackstr(expdest);
 170         exparg.lastp = &exparg.list;
 171         /*
 172          * TODO - EXP_REDIR
 173          */
 174         if (flag & EXP_FULL) {
 175                 ifsbreakup(p, &exparg);
 176                 *exparg.lastp = NULL;
 177                 exparg.lastp = &exparg.list;
 178                 expandmeta(exparg.list, flag);
 179         } else {
 180                 if (flag & EXP_REDIR) /*XXX - for now, just remove escapes */
 181                         rmescapes(p);
 182                 sp = (struct strlist *)stalloc(sizeof (struct strlist));
 183                 sp->text = p;
 184                 *exparg.lastp = sp;
 185                 exparg.lastp = &sp->next;
 186         }
 187         while (ifsfirst.next != NULL) {
 188                 struct ifsregion *ifsp;
 189                 INTOFF;
 190                 ifsp = ifsfirst.next->next;
 191                 ckfree(ifsfirst.next);
 192                 ifsfirst.next = ifsp;
 193                 INTON;
 194         }
 195         *exparg.lastp = NULL;
 196         if (exparg.list) {
 197                 *arglist->lastp = exparg.list;
 198                 arglist->lastp = exparg.lastp;
 199         }
 200 }
 201
 202
 203
 204 /*
 205  * Perform parameter expansion, command substitution and arithmetic
 206  * expansion, and tilde expansion if requested via EXP_TILDE/EXP_VARTILDE.
 207  * Processing ends at a CTLENDVAR character as well as '\0'.
 208  * This is used to expand word in ${var+word} etc.
 209  * If EXP_FULL, EXP_CASE or EXP_REDIR are set, keep and/or generate CTLESC
 210  * characters to allow for further processing.
 211  * If EXP_FULL is set, also preserve CTLQUOTEMARK characters.
 212  */
 213 static void
 214 argstr(char *p, int flag)
 215 {
 216         char c;
 217         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);  /* do CTLESC */
 218         int firsteq = 1;
 219
 220         if (*p == '~' && (flag & (EXP_TILDE | EXP_VARTILDE)))
 221                 p = exptilde(p, flag);
 222         for (;;) {
 223                 switch (c = *p++) {
 224                 case '\0':
 225                 case CTLENDVAR:
 226                         goto breakloop;
 227                 case CTLQUOTEMARK:
 228                         /* "$@" syntax adherence hack */
 229                         if (p[0] == CTLVAR && p[2] == '@' && p[3] == '=')
 230                                 break;
 231                         if ((flag & EXP_FULL) != 0)
 232                                 STPUTC(c, expdest);
 233                         break;
 234                 case CTLESC:
 235                         if (quotes)
 236                                 STPUTC(c, expdest);
 237                         c = *p++;
 238                         STPUTC(c, expdest);
 239                         break;
 240                 case CTLVAR:
 241                         p = evalvar(p, flag);
 242                         break;
 243                 case CTLBACKQ:
 244                 case CTLBACKQ|CTLQUOTE:
 245                         expbackq(argbackq->n, c & CTLQUOTE, flag);
 246                         argbackq = argbackq->next;
 247                         break;
 248                 case CTLENDARI:
 249                         expari(flag);
 250                         break;
 251                 case ':':
 252                 case '=':
 253                         /*
 254                          * sort of a hack - expand tildes in variable
 255                          * assignments (after the first '=' and after ':'s).
 256                          */
 257                         STPUTC(c, expdest);
 258                         if (flag & EXP_VARTILDE && *p == '~') {
 259                                 if (c == '=') {
 260                                         if (firsteq)
 261                                                 firsteq = 0;
 262                                         else
 263                                                 break;
 264                                 }
 265                                 p = exptilde(p, flag);
 266                         }
 267                         break;
 268                 default:
 269                         STPUTC(c, expdest);
 270                 }
 271         }
 272 breakloop:;
 273 }
 274
 275 /*
 276  * Perform tilde expansion, placing the result in the stack string and
 277  * returning the next position in the input string to process.
 278  */
 279 static char *
 280 exptilde(char *p, int flag)
 281 {
 282         char c, *startp = p;
 283         struct passwd *pw;
 284         char *home;
 285         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 286
 287         while ((c = *p) != '\0') {
 288                 switch(c) {
 289                 case CTLESC:
 290                         return (startp);
 291                 case CTLQUOTEMARK:
 292                         return (startp);
 293                 case ':':
 294                         if (flag & EXP_VARTILDE)
 295                                 goto done;
 296                         break;
 297                 case '/':
 298                         goto done;
 299                 }
 300                 p++;
 301         }
 302 done:
 303         *p = '\0';
 304         if (*(startp+1) == '\0') {
 305                 if ((home = lookupvar("HOME")) == NULL)
 306                         goto lose;
 307         } else {
 308                 if ((pw = getpwnam(startp+1)) == NULL)
 309                         goto lose;
 310                 home = pw->pw_dir;
 311         }
 312         if (*home == '\0')
 313                 goto lose;
 314         *p = c;
 315         while ((c = *home++) != '\0') {
 316                 if (quotes && SQSYNTAX[(int)c] == CCTL)
 317                         STPUTC(CTLESC, expdest);
 318                 STPUTC(c, expdest);
 319         }
 320         return (p);
 321 lose:
 322         *p = c;
 323         return (startp);
 324 }
 325
 326
 327 static void
 328 removerecordregions(int endoff)
 329 {
 330         if (ifslastp == NULL)
 331                 return;
 332
 333         if (ifsfirst.endoff > endoff) {
 334                 while (ifsfirst.next != NULL) {
 335                         struct ifsregion *ifsp;
 336                         INTOFF;
 337                         ifsp = ifsfirst.next->next;
 338                         ckfree(ifsfirst.next);
 339                         ifsfirst.next = ifsp;
 340                         INTON;
 341                 }
 342                 if (ifsfirst.begoff > endoff)
 343                         ifslastp = NULL;
 344                 else {
 345                         ifslastp = &ifsfirst;
 346                         ifsfirst.endoff = endoff;
 347                 }
 348                 return;
 349         }
 350
 351         ifslastp = &ifsfirst;
 352         while (ifslastp->next && ifslastp->next->begoff < endoff)
 353                 ifslastp=ifslastp->next;
 354         while (ifslastp->next != NULL) {
 355                 struct ifsregion *ifsp;
 356                 INTOFF;
 357                 ifsp = ifslastp->next->next;
 358                 ckfree(ifslastp->next);
 359                 ifslastp->next = ifsp;
 360                 INTON;
 361         }
 362         if (ifslastp->endoff > endoff)
 363                 ifslastp->endoff = endoff;
 364 }
 365
 366 /*
 367  * Expand arithmetic expression.  Backup to start of expression,
 368  * evaluate, place result in (backed up) result, adjust string position.
 369  */
 370 void
 371 expari(int flag)
 372 {
 373         char *p, *start;
 374         arith_t result;
 375         int begoff;
 376         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 377         int quoted;
 378
 379         /*
 380          * This routine is slightly over-complicated for
 381          * efficiency.  First we make sure there is
 382          * enough space for the result, which may be bigger
 383          * than the expression.  Next we
 384          * scan backwards looking for the start of arithmetic.  If the
 385          * next previous character is a CTLESC character, then we
 386          * have to rescan starting from the beginning since CTLESC
 387          * characters have to be processed left to right.
 388          */
 389         CHECKSTRSPACE(DIGITS(result) - 2, expdest);
 390         USTPUTC('\0', expdest);
 391         start = stackblock();
 392         p = expdest - 2;
 393         while (p >= start && *p != CTLARI)
 394                 --p;
 395         if (p < start || *p != CTLARI)
 396                 error("missing CTLARI (shouldn't happen)");
 397         if (p > start && *(p - 1) == CTLESC)
 398                 for (p = start; *p != CTLARI; p++)
 399                         if (*p == CTLESC)
 400                                 p++;
 401
 402         if (p[1] == '"')
 403                 quoted=1;
 404         else
 405                 quoted=0;
 406         begoff = p - start;
 407         removerecordregions(begoff);
 408         if (quotes)
 409                 rmescapes(p+2);
 410         result = arith(p+2);
 411         fmtstr(p, DIGITS(result), ARITH_FORMAT_STR, result);
 412         while (*p++)
 413                 ;
 414         if (quoted == 0)
 415                 recordregion(begoff, p - 1 - start, 0);
 416         result = expdest - p + 1;
 417         STADJUST(-result, expdest);
 418 }
 419
 420
 421 /*
 422  * Perform command substitution.
 423  */
 424 static void
 425 expbackq(union node *cmd, int quoted, int flag)
 426 {
 427         struct backcmd in;
 428         int i;
 429         char buf[128];
 430         char *p;
 431         char *dest = expdest;
 432         struct ifsregion saveifs, *savelastp;
 433         struct nodelist *saveargbackq;
 434         char lastc;
 435         int startloc = dest - stackblock();
 436         char const *syntax = quoted? DQSYNTAX : BASESYNTAX;
 437         int saveherefd;
 438         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 439         int nnl;
 440
 441         INTOFF;
 442         saveifs = ifsfirst;
 443         savelastp = ifslastp;
 444         saveargbackq = argbackq;
 445         saveherefd = herefd;
 446         herefd = -1;
 447         p = grabstackstr(dest);
 448         evalbackcmd(cmd, &in);
 449         ungrabstackstr(p, dest);
 450         ifsfirst = saveifs;
 451         ifslastp = savelastp;
 452         argbackq = saveargbackq;
 453         herefd = saveherefd;
 454
 455         p = in.buf;
 456         lastc = '\0';
 457         nnl = 0;
 458         /* Don't copy trailing newlines */
 459         for (;;) {
 460                 if (--in.nleft < 0) {
 461                         if (in.fd < 0)
 462                                 break;
 463                         while ((i = read(in.fd, buf, sizeof buf)) < 0 && errno == EINTR);
 464                         TRACE(("expbackq: read returns %d\n", i));
 465                         if (i <= 0)
 466                                 break;
 467                         p = buf;
 468                         in.nleft = i - 1;
 469                 }
 470                 lastc = *p++;
 471                 if (lastc != '\0') {
 472                         if (quotes && syntax[(int)lastc] == CCTL)
 473                                 STPUTC(CTLESC, dest);
 474                         if (lastc == '\n') {
 475                                 nnl++;
 476                         } else {
 477                                 while (nnl > 0) {
 478                                         nnl--;
 479                                         STPUTC('\n', dest);
 480                                 }
 481                                 STPUTC(lastc, dest);
 482                         }
 483                 }
 484         }
 485
 486         if (in.fd >= 0)
 487                 close(in.fd);
 488         if (in.buf)
 489                 ckfree(in.buf);
 490         if (in.jp)
 491                 exitstatus = waitforjob(in.jp, (int *)NULL);
 492         if (quoted == 0)
 493                 recordregion(startloc, dest - stackblock(), 0);
 494         TRACE(("evalbackq: size=%d: \"%.*s\"\n",
 495                 (dest - stackblock()) - startloc,
 496                 (dest - stackblock()) - startloc,
 497                 stackblock() + startloc));
 498         expdest = dest;
 499         INTON;
 500 }
 501
 502
 503
 504 static int
 505 subevalvar(char *p, char *str, int strloc, int subtype, int startloc,
 506   int varflags)
 507 {
 508         char *startp;
 509         char *loc = NULL;
 510         char *q;
 511         int c = 0;
 512         int saveherefd = herefd;
 513         struct nodelist *saveargbackq = argbackq;
 514         int amount;
 515
 516         herefd = -1;
 517         argstr(p, 0);
 518         STACKSTRNUL(expdest);
 519         herefd = saveherefd;
 520         argbackq = saveargbackq;
 521         startp = stackblock() + startloc;
 522         if (str == NULL)
 523             str = stackblock() + strloc;
 524
 525         switch (subtype) {
 526         case VSASSIGN:
 527                 setvar(str, startp, 0);
 528                 amount = startp - expdest;
 529                 STADJUST(amount, expdest);
 530                 varflags &= ~VSNUL;
 531                 if (c != 0)
 532                         *loc = c;
 533                 return 1;
 534
 535         case VSQUESTION:
 536                 if (*p != CTLENDVAR) {
 537                         outfmt(&errout, "%s\n", startp);
 538                         error((char *)NULL);
 539                 }
 540                 error("%.*s: parameter %snot set", (int)(p - str - 1),
 541                       str, (varflags & VSNUL) ? "null or "
 542                                               : nullstr);
 543                 return 0;
 544
 545         case VSTRIMLEFT:
 546                 for (loc = startp; loc < str; loc++) {
 547                         c = *loc;
 548                         *loc = '\0';
 549                         if (patmatch(str, startp, varflags & VSQUOTE)) {
 550                                 *loc = c;
 551                                 goto recordleft;
 552                         }
 553                         *loc = c;
 554                         if ((varflags & VSQUOTE) && *loc == CTLESC)
 555                                 loc++;
 556                 }
 557                 return 0;
 558
 559         case VSTRIMLEFTMAX:
 560                 for (loc = str - 1; loc >= startp;) {
 561                         c = *loc;
 562                         *loc = '\0';
 563                         if (patmatch(str, startp, varflags & VSQUOTE)) {
 564                                 *loc = c;
 565                                 goto recordleft;
 566                         }
 567                         *loc = c;
 568                         loc--;
 569                         if ((varflags & VSQUOTE) && loc > startp &&
 570                             *(loc - 1) == CTLESC) {
 571                                 for (q = startp; q < loc; q++)
 572                                         if (*q == CTLESC)
 573                                                 q++;
 574                                 if (q > loc)
 575                                         loc--;
 576                         }
 577                 }
 578                 return 0;
 579
 580         case VSTRIMRIGHT:
 581                 for (loc = str - 1; loc >= startp;) {
 582                         if (patmatch(str, loc, varflags & VSQUOTE)) {
 583                                 amount = loc - expdest;
 584                                 STADJUST(amount, expdest);
 585                                 return 1;
 586                         }
 587                         loc--;
 588                         if ((varflags & VSQUOTE) && loc > startp &&
 589                             *(loc - 1) == CTLESC) {
 590                                 for (q = startp; q < loc; q++)
 591                                         if (*q == CTLESC)
 592                                                 q++;
 593                                 if (q > loc)
 594                                         loc--;
 595                         }
 596                 }
 597                 return 0;
 598
 599         case VSTRIMRIGHTMAX:
 600                 for (loc = startp; loc < str - 1; loc++) {
 601                         if (patmatch(str, loc, varflags & VSQUOTE)) {
 602                                 amount = loc - expdest;
 603                                 STADJUST(amount, expdest);
 604                                 return 1;
 605                         }
 606                         if ((varflags & VSQUOTE) && *loc == CTLESC)
 607                                 loc++;
 608                 }
 609                 return 0;
 610
 611
 612         default:
 613                 abort();
 614         }
 615
 616 recordleft:
 617         amount = ((str - 1) - (loc - startp)) - expdest;
 618         STADJUST(amount, expdest);
 619         while (loc != str - 1)
 620                 *startp++ = *loc++;
 621         return 1;
 622 }
 623
 624
 625 /*
 626  * Expand a variable, and return a pointer to the next character in the
 627  * input string.
 628  */
 629
 630 static char *
 631 evalvar(char *p, int flag)
 632 {
 633         int subtype;
 634         int varflags;
 635         char *var;
 636         char *val;
 637         int patloc;
 638         int c;
 639         int set;
 640         int special;
 641         int startloc;
 642         int varlen;
 643         int easy;
 644         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 645
 646         varflags = (unsigned char)*p++;
 647         subtype = varflags & VSTYPE;
 648         var = p;
 649         special = 0;
 650         if (! is_name(*p))
 651                 special = 1;
 652         p = strchr(p, '=') + 1;
 653 again: /* jump here after setting a variable with ${var=text} */
 654         if (varflags & VSLINENO) {
 655                 set = 1;
 656                 special = 0;
 657                 val = var;
 658                 p[-1] = '\0';   /* temporarily overwrite '=' to have \0
 659                                    terminated string */
 660         } else if (special) {
 661                 set = varisset(var, varflags & VSNUL);
 662                 val = NULL;
 663         } else {
 664                 val = bltinlookup(var, 1);
 665                 if (val == NULL || ((varflags & VSNUL) && val[0] == '\0')) {
 666                         val = NULL;
 667                         set = 0;
 668                 } else
 669                         set = 1;
 670         }
 671         varlen = 0;
 672         startloc = expdest - stackblock();
 673         if (!set && uflag) {
 674                 switch (subtype) {
 675                 case VSNORMAL:
 676                 case VSTRIMLEFT:
 677                 case VSTRIMLEFTMAX:
 678                 case VSTRIMRIGHT:
 679                 case VSTRIMRIGHTMAX:
 680                 case VSLENGTH:
 681                         error("%.*s: parameter not set", (int)(p - var - 1),
 682                             var);
 683                 }
 684         }
 685         if (set && subtype != VSPLUS) {
 686                 /* insert the value of the variable */
 687                 if (special) {
 688                         varvalue(var, varflags & VSQUOTE, subtype, flag);
 689                         if (subtype == VSLENGTH) {
 690                                 varlen = expdest - stackblock() - startloc;
 691                                 STADJUST(-varlen, expdest);
 692                         }
 693                 } else {
 694                         char const *syntax = (varflags & VSQUOTE) ? DQSYNTAX
 695                                                                   : BASESYNTAX;
 696
 697                         if (subtype == VSLENGTH) {
 698                                 for (;*val; val++)
 699                                         varlen++;
 700                         }
 701                         else {
 702                                 while (*val) {
 703                                         if (quotes &&
 704                                             syntax[(int)*val] == CCTL)
 705                                                 STPUTC(CTLESC, expdest);
 706                                         STPUTC(*val++, expdest);
 707                                 }
 708
 709                         }
 710                 }
 711         }
 712
 713         if (subtype == VSPLUS)
 714                 set = ! set;
 715
 716         easy = ((varflags & VSQUOTE) == 0 ||
 717                 (*var == '@' && shellparam.nparam != 1));
 718
 719
 720         switch (subtype) {
 721         case VSLENGTH:
 722                 expdest = cvtnum(varlen, expdest);
 723                 goto record;
 724
 725         case VSNORMAL:
 726                 if (!easy)
 727                         break;
 728 record:
 729                 recordregion(startloc, expdest - stackblock(),
 730                              varflags & VSQUOTE);
 731                 break;
 732
 733         case VSPLUS:
 734         case VSMINUS:
 735                 if (!set) {
 736                         argstr(p, flag);
 737                         break;
 738                 }
 739                 if (easy)
 740                         goto record;
 741                 break;
 742
 743         case VSTRIMLEFT:
 744         case VSTRIMLEFTMAX:
 745         case VSTRIMRIGHT:
 746         case VSTRIMRIGHTMAX:
 747                 if (!set)
 748                         break;
 749                 /*
 750                  * Terminate the string and start recording the pattern
 751                  * right after it
 752                  */
 753                 STPUTC('\0', expdest);
 754                 patloc = expdest - stackblock();
 755                 if (subevalvar(p, NULL, patloc, subtype,
 756                                startloc, varflags) == 0) {
 757                         int amount = (expdest - stackblock() - patloc) + 1;
 758                         STADJUST(-amount, expdest);
 759                 }
 760                 /* Remove any recorded regions beyond start of variable */
 761                 removerecordregions(startloc);
 762                 goto record;
 763
 764         case VSASSIGN:
 765         case VSQUESTION:
 766                 if (!set) {
 767                         if (subevalvar(p, var, 0, subtype, startloc, varflags)) {
 768                                 varflags &= ~VSNUL;
 769                                 /*
 770                                  * Remove any recorded regions beyond
 771                                  * start of variable
 772                                  */
 773                                 removerecordregions(startloc);
 774                                 goto again;
 775                         }
 776                         break;
 777                 }
 778                 if (easy)
 779                         goto record;
 780                 break;
 781
 782         case VSERROR:
 783                 c = p - var - 1;
 784                 error("${%.*s%s}: Bad substitution", c, var,
 785                     (c > 0 && *p != CTLENDVAR) ? "..." : "");
 786
 787         default:
 788                 abort();
 789         }
 790         p[-1] = '=';    /* recover overwritten '=' */
 791
 792         if (subtype != VSNORMAL) {      /* skip to end of alternative */
 793                 int nesting = 1;
 794                 for (;;) {
 795                         if ((c = *p++) == CTLESC)
 796                                 p++;
 797                         else if (c == CTLBACKQ || c == (CTLBACKQ|CTLQUOTE)) {
 798                                 if (set)
 799                                         argbackq = argbackq->next;
 800                         } else if (c == CTLVAR) {
 801                                 if ((*p++ & VSTYPE) != VSNORMAL)
 802                                         nesting++;
 803                         } else if (c == CTLENDVAR) {
 804                                 if (--nesting == 0)
 805                                         break;
 806                         }
 807                 }
 808         }
 809         return p;
 810 }
 811
 812
 813
 814 /*
 815  * Test whether a specialized variable is set.
 816  */
 817
 818 static int
 819 varisset(char *name, int nulok)
 820 {
 821
 822         if (*name == '!')
 823                 return backgndpid != -1;
 824         else if (*name == '@' || *name == '*') {
 825                 if (*shellparam.p == NULL)
 826                         return 0;
 827
 828                 if (nulok) {
 829                         char **av;
 830
 831                         for (av = shellparam.p; *av; av++)
 832                                 if (**av != '\0')
 833                                         return 1;
 834                         return 0;
 835                 }
 836         } else if (is_digit(*name)) {
 837                 char *ap;
 838                 int num = atoi(name);
 839
 840                 if (num > shellparam.nparam)
 841                         return 0;
 842
 843                 if (num == 0)
 844                         ap = arg0;
 845                 else
 846                         ap = shellparam.p[num - 1];
 847
 848                 if (nulok && (ap == NULL || *ap == '\0'))
 849                         return 0;
 850         }
 851         return 1;
 852 }
 853
 854
 855
 856 /*
 857  * Add the value of a specialized variable to the stack string.
 858  */
 859
 860 static void
 861 varvalue(char *name, int quoted, int subtype, int flag)
 862 {
 863         int num;
 864         char *p;
 865         int i;
 866         char sep;
 867         char **ap;
 868         char const *syntax;
 869
 870 #define STRTODEST(p) \
 871         do {\
 872         if (flag & (EXP_FULL | EXP_CASE) && subtype != VSLENGTH) { \
 873                 syntax = quoted? DQSYNTAX : BASESYNTAX; \
 874                 while (*p) { \
 875                         if (syntax[(int)*p] == CCTL) \
 876                                 STPUTC(CTLESC, expdest); \
 877                         STPUTC(*p++, expdest); \
 878                 } \
 879         } else \
 880                 while (*p) \
 881                         STPUTC(*p++, expdest); \
 882         } while (0)
 883
 884
 885         switch (*name) {
 886         case '$':
 887                 num = rootpid;
 888                 goto numvar;
 889         case '?':
 890                 num = oexitstatus;
 891                 goto numvar;
 892         case '#':
 893                 num = shellparam.nparam;
 894                 goto numvar;
 895         case '!':
 896                 num = backgndpid;
 897 numvar:
 898                 expdest = cvtnum(num, expdest);
 899                 break;
 900         case '-':
 901                 for (i = 0 ; i < NOPTS ; i++) {
 902                         if (optlist[i].val)
 903                                 STPUTC(optlist[i].letter, expdest);
 904                 }
 905                 break;
 906         case '@':
 907                 if (flag & EXP_FULL && quoted) {
 908                         for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
 909                                 STRTODEST(p);
 910                                 if (*ap)
 911                                         STPUTC('\0', expdest);
 912                         }
 913                         break;
 914                 }
 915                 /* FALLTHROUGH */
 916         case '*':
 917                 if (ifsset())
 918                         sep = ifsval()[0];
 919                 else
 920                         sep = ' ';
 921                 for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
 922                         STRTODEST(p);
 923                         if (*ap && sep)
 924                                 STPUTC(sep, expdest);
 925                 }
 926                 break;
 927         case '0':
 928                 p = arg0;
 929                 STRTODEST(p);
 930                 break;
 931         default:
 932                 if (is_digit(*name)) {
 933                         num = atoi(name);
 934                         if (num > 0 && num <= shellparam.nparam) {
 935                                 p = shellparam.p[num - 1];
 936                                 STRTODEST(p);
 937                         }
 938                 }
 939                 break;
 940         }
 941 }
 942
 943
 944
 945 /*
 946  * Record the the fact that we have to scan this region of the
 947  * string for IFS characters.
 948  */
 949
 950 static void
 951 recordregion(int start, int end, int inquotes)
 952 {
 953         struct ifsregion *ifsp;
 954
 955         if (ifslastp == NULL) {
 956                 ifsp = &ifsfirst;
 957         } else {
 958                 if (ifslastp->endoff == start
 959                     && ifslastp->inquotes == inquotes) {
 960                         /* extend previous area */
 961                         ifslastp->endoff = end;
 962                         return;
 963                 }
 964                 ifsp = (struct ifsregion *)ckmalloc(sizeof (struct ifsregion));
 965                 ifslastp->next = ifsp;
 966         }
 967         ifslastp = ifsp;
 968         ifslastp->next = NULL;
 969         ifslastp->begoff = start;
 970         ifslastp->endoff = end;
 971         ifslastp->inquotes = inquotes;
 972 }
 973
 974
 975
 976 /*
 977  * Break the argument string into pieces based upon IFS and add the
 978  * strings to the argument list.  The regions of the string to be
 979  * searched for IFS characters have been stored by recordregion.
 980  * CTLESC characters are preserved but have little effect in this pass
 981  * other than escaping CTL* characters.  In particular, they do not escape
 982  * IFS characters: that should be done with the ifsregion mechanism.
 983  * CTLQUOTEMARK characters are used to preserve empty quoted strings.
 984  * This pass treats them as a regular character, making the string non-empty.
 985  * Later, they are removed along with the other CTL* characters.
 986  */
 987 static void
 988 ifsbreakup(char *string, struct arglist *arglist)
 989 {
 990         struct ifsregion *ifsp;
 991         struct strlist *sp;
 992         char *start;
 993         char *p;
 994         char *q;
 995         const char *ifs;
 996         const char *ifsspc;
 997         int had_param_ch = 0;
 998
 999         start = string;
1000
1001         if (ifslastp == NULL) {
1002                 /* Return entire argument, IFS doesn't apply to any of it */
1003                 sp = (struct strlist *)stalloc(sizeof *sp);
1004                 sp->text = start;
1005                 *arglist->lastp = sp;
1006                 arglist->lastp = &sp->next;
1007                 return;
1008         }
1009
1010         ifs = ifsset() ? ifsval() : " \t\n";
1011
1012         for (ifsp = &ifsfirst; ifsp != NULL; ifsp = ifsp->next) {
1013                 p = string + ifsp->begoff;
1014                 while (p < string + ifsp->endoff) {
1015                         q = p;
1016                         if (*p == CTLESC)
1017                                 p++;
1018                         if (ifsp->inquotes) {
1019                                 /* Only NULs (should be from "$@") end args */
1020                                 had_param_ch = 1;
1021                                 if (*p != 0) {
1022                                         p++;
1023                                         continue;
1024                                 }
1025                                 ifsspc = NULL;
1026                         } else {
1027                                 if (!strchr(ifs, *p)) {
1028                                         had_param_ch = 1;
1029                                         p++;
1030                                         continue;
1031                                 }
1032                                 ifsspc = strchr(" \t\n", *p);
1033
1034                                 /* Ignore IFS whitespace at start */
1035                                 if (q == start && ifsspc != NULL) {
1036                                         p++;
1037                                         start = p;
1038                                         continue;
1039                                 }
1040                                 had_param_ch = 0;
1041                         }
1042
1043                         /* Save this argument... */
1044                         *q = '\0';
1045                         sp = (struct strlist *)stalloc(sizeof *sp);
1046                         sp->text = start;
1047                         *arglist->lastp = sp;
1048                         arglist->lastp = &sp->next;
1049                         p++;
1050
1051                         if (ifsspc != NULL) {
1052                                 /* Ignore further trailing IFS whitespace */
1053                                 for (; p < string + ifsp->endoff; p++) {
1054                                         q = p;
1055                                         if (*p == CTLESC)
1056                                                 p++;
1057                                         if (strchr(ifs, *p) == NULL) {
1058                                                 p = q;
1059                                                 break;
1060                                         }
1061                                         if (strchr(" \t\n", *p) == NULL) {
1062                                                 p++;
1063                                                 break;
1064                                         }
1065                                 }
1066                         }
1067                         start = p;
1068                 }
1069         }
1070
1071         /*
1072          * Save anything left as an argument.
1073          * Traditionally we have treated 'IFS=':'; set -- x$IFS' as
1074          * generating 2 arguments, the second of which is empty.
1075          * Some recent clarification of the Posix spec say that it
1076          * should only generate one....
1077          */
1078         if (had_param_ch || *start != 0) {
1079                 sp = (struct strlist *)stalloc(sizeof *sp);
1080                 sp->text = start;
1081                 *arglist->lastp = sp;
1082                 arglist->lastp = &sp->next;
1083         }
1084 }
1085
1086
1087 static char expdir[PATH_MAX];
1088 #define expdir_end (expdir + sizeof(expdir))
1089
1090 /*
1091  * Perform pathname generation and remove control characters.
1092  * At this point, the only control characters should be CTLESC and CTLQUOTEMARK.
1093  * The results are stored in the list exparg.
1094  */
1095 static void
1096 expandmeta(struct strlist *str, int flag __unused)
1097 {
1098         char *p;
1099         struct strlist **savelastp;
1100         struct strlist *sp;
1101         char c;
1102         /* TODO - EXP_REDIR */
1103
1104         while (str) {
1105                 if (fflag)
1106                         goto nometa;
1107                 p = str->text;
1108                 for (;;) {                      /* fast check for meta chars */
1109                         if ((c = *p++) == '\0')
1110                                 goto nometa;
1111                         if (c == '*' || c == '?' || c == '[' || c == '!')
1112                                 break;
1113                 }
1114                 savelastp = exparg.lastp;
1115                 INTOFF;
1116                 expmeta(expdir, str->text);
1117                 INTON;
1118                 if (exparg.lastp == savelastp) {
1119                         /*
1120                          * no matches
1121                          */
1122 nometa:
1123                         *exparg.lastp = str;
1124                         rmescapes(str->text);
1125                         exparg.lastp = &str->next;
1126                 } else {
1127                         *exparg.lastp = NULL;
1128                         *savelastp = sp = expsort(*savelastp);
1129                         while (sp->next != NULL)
1130                                 sp = sp->next;
1131                         exparg.lastp = &sp->next;
1132                 }
1133                 str = str->next;
1134         }
1135 }
1136
1137
1138 /*
1139  * Do metacharacter (i.e. *, ?, [...]) expansion.
1140  */
1141
1142 static void
1143 expmeta(char *enddir, char *name)
1144 {
1145         char *p;
1146         char *q;
1147         char *start;
1148         char *endname;
1149         int metaflag;
1150         struct stat statb;
1151         DIR *dirp;
1152         struct dirent *dp;
1153         int atend;
1154         int matchdot;
1155         int esc;
1156
1157         metaflag = 0;
1158         start = name;
1159         for (p = name; esc = 0, *p; p += esc + 1) {
1160                 if (*p == '*' || *p == '?')
1161                         metaflag = 1;
1162                 else if (*p == '[') {
1163                         q = p + 1;
1164                         if (*q == '!' || *q == '^')
1165                                 q++;
1166                         for (;;) {
1167                                 while (*q == CTLQUOTEMARK)
1168                                         q++;
1169                                 if (*q == CTLESC)
1170                                         q++;
1171                                 if (*q == '/' || *q == '\0')
1172                                         break;
1173                                 if (*++q == ']') {
1174                                         metaflag = 1;
1175                                         break;
1176                                 }
1177                         }
1178                 } else if (*p == '!' && p[1] == '!'     && (p == name || p[-1] == '/')) {
1179                         metaflag = 1;
1180                 } else if (*p == '\0')
1181                         break;
1182                 else if (*p == CTLQUOTEMARK)
1183                         continue;
1184                 else {
1185                         if (*p == CTLESC)
1186                                 esc++;
1187                         if (p[esc] == '/') {
1188                                 if (metaflag)
1189                                         break;
1190                                 start = p + esc + 1;
1191                         }
1192                 }
1193         }
1194         if (metaflag == 0) {    /* we've reached the end of the file name */
1195                 if (enddir != expdir)
1196                         metaflag++;
1197                 for (p = name ; ; p++) {
1198                         if (*p == CTLQUOTEMARK)
1199                                 continue;
1200                         if (*p == CTLESC)
1201                                 p++;
1202                         *enddir++ = *p;
1203                         if (*p == '\0')
1204                                 break;
1205                         if (enddir == expdir_end)
1206                                 return;
1207                 }
1208                 if (metaflag == 0 || lstat(expdir, &statb) >= 0)
1209                         addfname(expdir);
1210                 return;
1211         }
1212         endname = p;
1213         if (start != name) {
1214                 p = name;
1215                 while (p < start) {
1216                         while (*p == CTLQUOTEMARK)
1217                                 p++;
1218                         if (*p == CTLESC)
1219                                 p++;
1220                         *enddir++ = *p++;
1221                         if (enddir == expdir_end)
1222                                 return;
1223                 }
1224         }
1225         if (enddir == expdir) {
1226                 p = ".";
1227         } else if (enddir == expdir + 1 && *expdir == '/') {
1228                 p = "/";
1229         } else {
1230                 p = expdir;
1231                 enddir[-1] = '\0';
1232         }
1233         if ((dirp = opendir(p)) == NULL)
1234                 return;
1235         if (enddir != expdir)
1236                 enddir[-1] = '/';
1237         if (*endname == 0) {
1238                 atend = 1;
1239         } else {
1240                 atend = 0;
1241                 *endname = '\0';
1242                 endname += esc + 1;
1243         }
1244         matchdot = 0;
1245         p = start;
1246         while (*p == CTLQUOTEMARK)
1247                 p++;
1248         if (*p == CTLESC)
1249                 p++;
1250         if (*p == '.')
1251                 matchdot++;
1252         while (! int_pending() && (dp = readdir(dirp)) != NULL) {
1253                 if (dp->d_name[0] == '.' && ! matchdot)
1254                         continue;
1255                 if (patmatch(start, dp->d_name, 0)) {
1256                         if (enddir + dp->d_namlen + 1 > expdir_end)
1257                                 continue;
1258                         memcpy(enddir, dp->d_name, dp->d_namlen + 1);
1259                         if (atend)
1260                                 addfname(expdir);
1261                         else {
1262                                 if (enddir + dp->d_namlen + 2 > expdir_end)
1263                                         continue;
1264                                 enddir[dp->d_namlen] = '/';
1265                                 enddir[dp->d_namlen + 1] = '\0';
1266                                 expmeta(enddir + dp->d_namlen + 1, endname);
1267                         }
1268                 }
1269         }
1270         closedir(dirp);
1271         if (! atend)
1272                 endname[-esc - 1] = esc ? CTLESC : '/';
1273 }
1274
1275
1276 /*
1277  * Add a file name to the list.
1278  */
1279
1280 static void
1281 addfname(char *name)
1282 {
1283         char *p;
1284         struct strlist *sp;
1285
1286         p = stalloc(strlen(name) + 1);
1287         scopy(name, p);
1288         sp = (struct strlist *)stalloc(sizeof *sp);
1289         sp->text = p;
1290         *exparg.lastp = sp;
1291         exparg.lastp = &sp->next;
1292 }
1293
1294
1295 /*
1296  * Sort the results of file name expansion.  It calculates the number of
1297  * strings to sort and then calls msort (short for merge sort) to do the
1298  * work.
1299  */
1300
1301 static struct strlist *
1302 expsort(struct strlist *str)
1303 {
1304         int len;
1305         struct strlist *sp;
1306
1307         len = 0;
1308         for (sp = str ; sp ; sp = sp->next)
1309                 len++;
1310         return msort(str, len);
1311 }
1312
1313
1314 static struct strlist *
1315 msort(struct strlist *list, int len)
1316 {
1317         struct strlist *p, *q = NULL;
1318         struct strlist **lpp;
1319         int half;
1320         int n;
1321
1322         if (len <= 1)
1323                 return list;
1324         half = len >> 1;
1325         p = list;
1326         for (n = half ; --n >= 0 ; ) {
1327                 q = p;
1328                 p = p->next;
1329         }
1330         q->next = NULL;                 /* terminate first half of list */
1331         q = msort(list, half);          /* sort first half of list */
1332         p = msort(p, len - half);               /* sort second half */
1333         lpp = &list;
1334         for (;;) {
1335                 if (strcmp(p->text, q->text) < 0) {
1336                         *lpp = p;
1337                         lpp = &p->next;
1338                         if ((p = *lpp) == NULL) {
1339                                 *lpp = q;
1340                                 break;
1341                         }
1342                 } else {
1343                         *lpp = q;
1344                         lpp = &q->next;
1345                         if ((q = *lpp) == NULL) {
1346                                 *lpp = p;
1347                                 break;
1348                         }
1349                 }
1350         }
1351         return list;
1352 }
1353
1354
1355
1356 /*
1357  * Returns true if the pattern matches the string.
1358  */
1359
1360 int
1361 patmatch(const char *pattern, const char *string, int squoted)
1362 {
1363 #ifdef notdef
1364         if (pattern[0] == '!' && pattern[1] == '!')
1365                 return 1 - pmatch(pattern + 2, string);
1366         else
1367 #endif
1368                 return pmatch(pattern, string, squoted);
1369 }
1370
1371
1372 static int
1373 pmatch(const char *pattern, const char *string, int squoted)
1374 {
1375         const char *p, *q;
1376         char c;
1377
1378         p = pattern;
1379         q = string;
1380         for (;;) {
1381                 switch (c = *p++) {
1382                 case '\0':
1383                         goto breakloop;
1384                 case CTLESC:
1385                         if (squoted && *q == CTLESC)
1386                                 q++;
1387                         if (*q++ != *p++)
1388                                 return 0;
1389                         break;
1390                 case CTLQUOTEMARK:
1391                         continue;
1392                 case '?':
1393                         if (squoted && *q == CTLESC)
1394                                 q++;
1395                         if (*q++ == '\0')
1396                                 return 0;
1397                         break;
1398                 case '*':
1399                         c = *p;
1400                         while (c == CTLQUOTEMARK || c == '*')
1401                                 c = *++p;
1402                         if (c != CTLESC &&  c != CTLQUOTEMARK &&
1403                             c != '?' && c != '*' && c != '[') {
1404                                 while (*q != c) {
1405                                         if (squoted && *q == CTLESC &&
1406                                             q[1] == c)
1407                                                 break;
1408                                         if (*q == '\0')
1409                                                 return 0;
1410                                         if (squoted && *q == CTLESC)
1411                                                 q++;
1412                                         q++;
1413                                 }
1414                         }
1415                         do {
1416                                 if (pmatch(p, q, squoted))
1417                                         return 1;
1418                                 if (squoted && *q == CTLESC)
1419                                         q++;
1420                         } while (*q++ != '\0');
1421                         return 0;
1422                 case '[': {
1423                         const char *endp;
1424                         int invert, found;
1425                         char chr;
1426
1427                         endp = p;
1428                         if (*endp == '!' || *endp == '^')
1429                                 endp++;
1430                         for (;;) {
1431                                 while (*endp == CTLQUOTEMARK)
1432                                         endp++;
1433                                 if (*endp == '\0')
1434                                         goto dft;               /* no matching ] */
1435                                 if (*endp == CTLESC)
1436                                         endp++;
1437                                 if (*++endp == ']')
1438                                         break;
1439                         }
1440                         invert = 0;
1441                         if (*p == '!' || *p == '^') {
1442                                 invert++;
1443                                 p++;
1444                         }
1445                         found = 0;
1446                         chr = *q++;
1447                         if (squoted && chr == CTLESC)
1448                                 chr = *q++;
1449                         if (chr == '\0')
1450                                 return 0;
1451                         c = *p++;
1452                         do {
1453                                 if (c == CTLQUOTEMARK)
1454                                         continue;
1455                                 if (c == CTLESC)
1456                                         c = *p++;
1457                                 if (*p == '-' && p[1] != ']') {
1458                                         p++;
1459                                         while (*p == CTLQUOTEMARK)
1460                                                 p++;
1461                                         if (*p == CTLESC)
1462                                                 p++;
1463                                         if (   collate_range_cmp(chr, c) >= 0
1464                                             && collate_range_cmp(chr, *p) <= 0
1465                                            )
1466                                                 found = 1;
1467                                         p++;
1468                                 } else {
1469                                         if (chr == c)
1470                                                 found = 1;
1471                                 }
1472                         } while ((c = *p++) != ']');
1473                         if (found == invert)
1474                                 return 0;
1475                         break;
1476                 }
1477 dft:            default:
1478                         if (squoted && *q == CTLESC)
1479                                 q++;
1480                         if (*q++ != c)
1481                                 return 0;
1482                         break;
1483                 }
1484         }
1485 breakloop:
1486         if (*q != '\0')
1487                 return 0;
1488         return 1;
1489 }
1490
1491
1492
1493 /*
1494  * Remove any CTLESC and CTLQUOTEMARK characters from a string.
1495  */
1496
1497 void
1498 rmescapes(char *str)
1499 {
1500         char *p, *q;
1501
1502         p = str;
1503         while (*p != CTLESC && *p != CTLQUOTEMARK) {
1504                 if (*p++ == '\0')
1505                         return;
1506         }
1507         q = p;
1508         while (*p) {
1509                 if (*p == CTLQUOTEMARK) {
1510                         p++;
1511                         continue;
1512                 }
1513                 if (*p == CTLESC)
1514                         p++;
1515                 *q++ = *p++;
1516         }
1517         *q = '\0';
1518 }
1519
1520
1521
1522 /*
1523  * See if a pattern matches in a case statement.
1524  */
1525
1526 int
1527 casematch(union node *pattern, const char *val)
1528 {
1529         struct stackmark smark;
1530         int result;
1531         char *p;
1532
1533         setstackmark(&smark);
1534         argbackq = pattern->narg.backquote;
1535         STARTSTACKSTR(expdest);
1536         ifslastp = NULL;
1537         argstr(pattern->narg.text, EXP_TILDE | EXP_CASE);
1538         STPUTC('\0', expdest);
1539         p = grabstackstr(expdest);
1540         result = patmatch(p, val, 0);
1541         popstackmark(&smark);
1542         return result;
1543 }
1544
1545 /*
1546  * Our own itoa().
1547  */
1548
1549 static char *
1550 cvtnum(int num, char *buf)
1551 {
1552         char temp[32];
1553         int neg = num < 0;
1554         char *p = temp + 31;
1555
1556         temp[31] = '\0';
1557
1558         do {
1559                 *--p = num % 10 + '0';
1560         } while ((num /= 10) != 0);
1561
1562         if (neg)
1563                 *--p = '-';
1564
1565         while (*p)
1566                 STPUTC(*p++, buf);
1567         return buf;
1568 }
1569
1570 /*
1571  * Do most of the work for wordexp(3).
1572  */
1573
1574 int
1575 wordexpcmd(int argc, char **argv)
1576 {
1577         size_t len;
1578         int i;
1579
1580         out1fmt("%08x", argc - 1);
1581         for (i = 1, len = 0; i < argc; i++)
1582                 len += strlen(argv[i]);
1583         out1fmt("%08x", (int)len);
1584         for (i = 1; i < argc; i++) {
1585                 out1str(argv[i]);
1586                 out1c('\0');
1587         }
1588         return (0);
1589 }