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  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *      This product includes software developed by the University of
  21  *      California, Berkeley and its contributors.
  22  * 4. Neither the name of the University nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  *
  38  * @(#)expand.c 8.5 (Berkeley) 5/15/95
  39  * $FreeBSD: src/bin/sh/expand.c,v 1.84 2011/05/07 14:32:16 jilles Exp $
  40  */
  41
  42 #include <sys/types.h>
  43 #include <sys/time.h>
  44 #include <sys/stat.h>
  45 #include <dirent.h>
  46 #include <errno.h>
  47 #include <inttypes.h>
  48 #include <limits.h>
  49 #include <pwd.h>
  50 #include <stdio.h>
  51 #include <stdlib.h>
  52 #include <string.h>
  53 #include <unistd.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, 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 char *cvtnum(int, char *);
 113 static int collate_range_cmp(int, int);
 114
 115 static int
 116 collate_range_cmp(int c1, int c2)
 117 {
 118         static char s1[2], s2[2];
 119
 120         s1[0] = c1;
 121         s2[0] = c2;
 122         return (strcoll(s1, s2));
 123 }
 124
 125 /*
 126  * Expand shell variables and backquotes inside a here document.
 127  *      union node *arg         the document
 128  *      int fd;                 where to write the expanded version
 129  */
 130
 131 void
 132 expandhere(union node *arg, int fd)
 133 {
 134         expandarg(arg, NULL, 0);
 135         xwrite(fd, stackblock(), expdest - stackblock());
 136 }
 137
 138 static char *
 139 stputs_quotes(const char *data, const char *syntax, char *p)
 140 {
 141         while (*data) {
 142                 CHECKSTRSPACE(2, p);
 143                 if (syntax[(int)*data] == CCTL)
 144                         USTPUTC(CTLESC, p);
 145                 USTPUTC(*data++, p);
 146         }
 147         return (p);
 148 }
 149 #define STPUTS_QUOTES(data, syntax, p) p = stputs_quotes((data), syntax, p)
 150
 151 /*
 152  * Perform expansions on an argument, placing the resulting list of arguments
 153  * in arglist.  Parameter expansion, command substitution and arithmetic
 154  * expansion are always performed; additional expansions can be requested
 155  * via flag (EXP_*).
 156  * The result is left in the stack string.
 157  * When arglist is NULL, perform here document expansion.
 158  *
 159  * Caution: this function uses global state and is not reentrant.
 160  * However, a new invocation after an interrupted invocation is safe
 161  * and will reset the global state for the new call.
 162  */
 163 void
 164 expandarg(union node *arg, struct arglist *arglist, int flag)
 165 {
 166         struct strlist *sp;
 167         char *p;
 168
 169         argbackq = arg->narg.backquote;
 170         STARTSTACKSTR(expdest);
 171         ifsfirst.next = NULL;
 172         ifslastp = NULL;
 173         argstr(arg->narg.text, flag);
 174         if (arglist == NULL) {
 175                 return;                 /* here document expanded */
 176         }
 177         STPUTC('\0', expdest);
 178         p = grabstackstr(expdest);
 179         exparg.lastp = &exparg.list;
 180         /*
 181          * TODO - EXP_REDIR
 182          */
 183         if (flag & EXP_FULL) {
 184                 ifsbreakup(p, &exparg);
 185                 *exparg.lastp = NULL;
 186                 exparg.lastp = &exparg.list;
 187                 expandmeta(exparg.list, flag);
 188         } else {
 189                 if (flag & EXP_REDIR) /*XXX - for now, just remove escapes */
 190                         rmescapes(p);
 191                 sp = (struct strlist *)stalloc(sizeof (struct strlist));
 192                 sp->text = p;
 193                 *exparg.lastp = sp;
 194                 exparg.lastp = &sp->next;
 195         }
 196         while (ifsfirst.next != NULL) {
 197                 struct ifsregion *ifsp;
 198                 INTOFF;
 199                 ifsp = ifsfirst.next->next;
 200                 ckfree(ifsfirst.next);
 201                 ifsfirst.next = ifsp;
 202                 INTON;
 203         }
 204         *exparg.lastp = NULL;
 205         if (exparg.list) {
 206                 *arglist->lastp = exparg.list;
 207                 arglist->lastp = exparg.lastp;
 208         }
 209 }
 210
 211
 212
 213 /*
 214  * Perform parameter expansion, command substitution and arithmetic
 215  * expansion, and tilde expansion if requested via EXP_TILDE/EXP_VARTILDE.
 216  * Processing ends at a CTLENDVAR character as well as '\0'.
 217  * This is used to expand word in ${var+word} etc.
 218  * If EXP_FULL, EXP_CASE or EXP_REDIR are set, keep and/or generate CTLESC
 219  * characters to allow for further processing.
 220  * If EXP_FULL is set, also preserve CTLQUOTEMARK characters.
 221  */
 222 static void
 223 argstr(char *p, int flag)
 224 {
 225         char c;
 226         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);  /* do CTLESC */
 227         int firsteq = 1;
 228         int split_lit;
 229         int lit_quoted;
 230
 231         split_lit = flag & EXP_SPLIT_LIT;
 232         lit_quoted = flag & EXP_LIT_QUOTED;
 233         flag &= ~(EXP_SPLIT_LIT | EXP_LIT_QUOTED);
 234         if (*p == '~' && (flag & (EXP_TILDE | EXP_VARTILDE)))
 235                 p = exptilde(p, flag);
 236         for (;;) {
 237                 CHECKSTRSPACE(2, expdest);
 238                 switch (c = *p++) {
 239                 case '\0':
 240                 case CTLENDVAR:
 241                         goto breakloop;
 242                 case CTLQUOTEMARK:
 243                         lit_quoted = 1;
 244                         /* "$@" syntax adherence hack */
 245                         if (p[0] == CTLVAR && p[2] == '@' && p[3] == '=')
 246                                 break;
 247                         if ((flag & EXP_FULL) != 0)
 248                                 USTPUTC(c, expdest);
 249                         break;
 250                 case CTLQUOTEEND:
 251                         lit_quoted = 0;
 252                         break;
 253                 case CTLESC:
 254                         if (quotes)
 255                                 USTPUTC(c, expdest);
 256                         c = *p++;
 257                         USTPUTC(c, expdest);
 258                         if (split_lit && !lit_quoted)
 259                                 recordregion(expdest - stackblock() -
 260                                     (quotes ? 2 : 1),
 261                                     expdest - stackblock(), 0);
 262                         break;
 263                 case CTLVAR:
 264                         p = evalvar(p, flag);
 265                         break;
 266                 case CTLBACKQ:
 267                 case CTLBACKQ|CTLQUOTE:
 268                         expbackq(argbackq->n, c & CTLQUOTE, flag);
 269                         argbackq = argbackq->next;
 270                         break;
 271                 case CTLENDARI:
 272                         expari(flag);
 273                         break;
 274                 case ':':
 275                 case '=':
 276                         /*
 277                          * sort of a hack - expand tildes in variable
 278                          * assignments (after the first '=' and after ':'s).
 279                          */
 280                         USTPUTC(c, expdest);
 281                         if (split_lit && !lit_quoted)
 282                                 recordregion(expdest - stackblock() - 1,
 283                                     expdest - stackblock(), 0);
 284                         if (flag & EXP_VARTILDE && *p == '~' &&
 285                             (c != '=' || firsteq)) {
 286                                 if (c == '=')
 287                                         firsteq = 0;
 288                                 p = exptilde(p, flag);
 289                         }
 290                         break;
 291                 default:
 292                         USTPUTC(c, expdest);
 293                         if (split_lit && !lit_quoted)
 294                                 recordregion(expdest - stackblock() - 1,
 295                                     expdest - stackblock(), 0);
 296                 }
 297         }
 298 breakloop:;
 299 }
 300
 301 /*
 302  * Perform tilde expansion, placing the result in the stack string and
 303  * returning the next position in the input string to process.
 304  */
 305 static char *
 306 exptilde(char *p, int flag)
 307 {
 308         char c, *startp = p;
 309         struct passwd *pw;
 310         char *home;
 311         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 312
 313         while ((c = *p) != '\0') {
 314                 switch(c) {
 315                 case CTLESC: /* This means CTL* are always considered quoted. */
 316                 case CTLVAR:
 317                 case CTLBACKQ:
 318                 case CTLBACKQ | CTLQUOTE:
 319                 case CTLARI:
 320                 case CTLENDARI:
 321                 case CTLQUOTEMARK:
 322                         return (startp);
 323                 case ':':
 324                         if (flag & EXP_VARTILDE)
 325                                 goto done;
 326                         break;
 327                 case '/':
 328                 case CTLENDVAR:
 329                         goto done;
 330                 }
 331                 p++;
 332         }
 333 done:
 334         *p = '\0';
 335         if (*(startp+1) == '\0') {
 336                 if ((home = lookupvar("HOME")) == NULL)
 337                         goto lose;
 338         } else {
 339                 if ((pw = getpwnam(startp+1)) == NULL)
 340                         goto lose;
 341                 home = pw->pw_dir;
 342         }
 343         if (*home == '\0')
 344                 goto lose;
 345         *p = c;
 346         if (quotes)
 347                 STPUTS_QUOTES(home, SQSYNTAX, expdest);
 348         else
 349                 STPUTS(home, expdest);
 350         return (p);
 351 lose:
 352         *p = c;
 353         return (startp);
 354 }
 355
 356
 357 static void
 358 removerecordregions(int endoff)
 359 {
 360         if (ifslastp == NULL)
 361                 return;
 362
 363         if (ifsfirst.endoff > endoff) {
 364                 while (ifsfirst.next != NULL) {
 365                         struct ifsregion *ifsp;
 366                         INTOFF;
 367                         ifsp = ifsfirst.next->next;
 368                         ckfree(ifsfirst.next);
 369                         ifsfirst.next = ifsp;
 370                         INTON;
 371                 }
 372                 if (ifsfirst.begoff > endoff)
 373                         ifslastp = NULL;
 374                 else {
 375                         ifslastp = &ifsfirst;
 376                         ifsfirst.endoff = endoff;
 377                 }
 378                 return;
 379         }
 380
 381         ifslastp = &ifsfirst;
 382         while (ifslastp->next && ifslastp->next->begoff < endoff)
 383                 ifslastp=ifslastp->next;
 384         while (ifslastp->next != NULL) {
 385                 struct ifsregion *ifsp;
 386                 INTOFF;
 387                 ifsp = ifslastp->next->next;
 388                 ckfree(ifslastp->next);
 389                 ifslastp->next = ifsp;
 390                 INTON;
 391         }
 392         if (ifslastp->endoff > endoff)
 393                 ifslastp->endoff = endoff;
 394 }
 395
 396 /*
 397  * Expand arithmetic expression.  Backup to start of expression,
 398  * evaluate, place result in (backed up) result, adjust string position.
 399  */
 400 void
 401 expari(int flag)
 402 {
 403         char *p, *q, *start;
 404         arith_t result;
 405         int begoff;
 406         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 407         int quoted;
 408
 409         /*
 410          * This routine is slightly over-complicated for
 411          * efficiency.  First we make sure there is
 412          * enough space for the result, which may be bigger
 413          * than the expression.  Next we
 414          * scan backwards looking for the start of arithmetic.  If the
 415          * next previous character is a CTLESC character, then we
 416          * have to rescan starting from the beginning since CTLESC
 417          * characters have to be processed left to right.
 418          */
 419         CHECKSTRSPACE(DIGITS(result) - 2, expdest);
 420         USTPUTC('\0', expdest);
 421         start = stackblock();
 422         p = expdest - 2;
 423         while (p >= start && *p != CTLARI)
 424                 --p;
 425         if (p < start || *p != CTLARI)
 426                 error("missing CTLARI (shouldn't happen)");
 427         if (p > start && *(p - 1) == CTLESC)
 428                 for (p = start; *p != CTLARI; p++)
 429                         if (*p == CTLESC)
 430                                 p++;
 431
 432         if (p[1] == '"')
 433                 quoted=1;
 434         else
 435                 quoted=0;
 436         begoff = p - start;
 437         removerecordregions(begoff);
 438         if (quotes)
 439                 rmescapes(p+2);
 440         q = grabstackstr(expdest);
 441         result = arith(p+2);
 442         ungrabstackstr(q, expdest);
 443         fmtstr(p, DIGITS(result), ARITH_FORMAT_STR, result);
 444         while (*p++)
 445                 ;
 446         if (quoted == 0)
 447                 recordregion(begoff, p - 1 - start, 0);
 448         result = expdest - p + 1;
 449         STADJUST(-result, expdest);
 450 }
 451
 452
 453 /*
 454  * Perform command substitution.
 455  */
 456 static void
 457 expbackq(union node *cmd, int quoted, int flag)
 458 {
 459         struct backcmd in;
 460         int i;
 461         char buf[128];
 462         char *p;
 463         char *dest = expdest;
 464         struct ifsregion saveifs, *savelastp;
 465         struct nodelist *saveargbackq;
 466         char lastc;
 467         int startloc = dest - stackblock();
 468         char const *syntax = quoted? DQSYNTAX : BASESYNTAX;
 469         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 470         int nnl;
 471
 472         INTOFF;
 473         saveifs = ifsfirst;
 474         savelastp = ifslastp;
 475         saveargbackq = argbackq;
 476         p = grabstackstr(dest);
 477         evalbackcmd(cmd, &in);
 478         ungrabstackstr(p, dest);
 479         ifsfirst = saveifs;
 480         ifslastp = savelastp;
 481         argbackq = saveargbackq;
 482
 483         p = in.buf;
 484         lastc = '\0';
 485         nnl = 0;
 486         /* Don't copy trailing newlines */
 487         for (;;) {
 488                 if (--in.nleft < 0) {
 489                         if (in.fd < 0)
 490                                 break;
 491                         while ((i = read(in.fd, buf, sizeof buf)) < 0 && errno == EINTR);
 492                         TRACE(("expbackq: read returns %d\n", i));
 493                         if (i <= 0)
 494                                 break;
 495                         p = buf;
 496                         in.nleft = i - 1;
 497                 }
 498                 lastc = *p++;
 499                 if (lastc != '\0') {
 500                         if (lastc == '\n') {
 501                                 nnl++;
 502                         } else {
 503                                 CHECKSTRSPACE(nnl + 2, dest);
 504                                 while (nnl > 0) {
 505                                         nnl--;
 506                                         USTPUTC('\n', dest);
 507                                 }
 508                                 if (quotes && syntax[(int)lastc] == CCTL)
 509                                         USTPUTC(CTLESC, dest);
 510                                 USTPUTC(lastc, dest);
 511                         }
 512                 }
 513         }
 514
 515         if (in.fd >= 0)
 516                 close(in.fd);
 517         if (in.buf)
 518                 ckfree(in.buf);
 519         if (in.jp)
 520                 exitstatus = waitforjob(in.jp, NULL);
 521         if (quoted == 0)
 522                 recordregion(startloc, dest - stackblock(), 0);
 523         TRACE(("expbackq: size=%td: \"%.*s\"\n",
 524                 ((dest - stackblock()) - startloc),
 525                 (int)((dest - stackblock()) - startloc),
 526                 stackblock() + startloc));
 527         expdest = dest;
 528         INTON;
 529 }
 530
 531
 532
 533 static int
 534 subevalvar(char *p, char *str, int strloc, int subtype, int startloc,
 535   int varflags, int quotes)
 536 {
 537         char *startp;
 538         char *loc = NULL;
 539         char *q;
 540         int c = 0;
 541         struct nodelist *saveargbackq = argbackq;
 542         int amount;
 543
 544         argstr(p, (subtype == VSTRIMLEFT || subtype == VSTRIMLEFTMAX ||
 545             subtype == VSTRIMRIGHT || subtype == VSTRIMRIGHTMAX ?
 546             EXP_CASE : 0) | EXP_TILDE);
 547         STACKSTRNUL(expdest);
 548         argbackq = saveargbackq;
 549         startp = stackblock() + startloc;
 550         if (str == NULL)
 551             str = stackblock() + strloc;
 552
 553         switch (subtype) {
 554         case VSASSIGN:
 555                 setvar(str, startp, 0);
 556                 amount = startp - expdest;
 557                 STADJUST(amount, expdest);
 558                 varflags &= ~VSNUL;
 559                 return 1;
 560
 561         case VSQUESTION:
 562                 if (*p != CTLENDVAR) {
 563                         outfmt(out2, "%s\n", startp);
 564                         error(NULL);
 565                 }
 566                 error("%.*s: parameter %snot set", (int)(p - str - 1),
 567                       str, (varflags & VSNUL) ? "null or "
 568                                               : nullstr);
 569                 return 0;
 570
 571         case VSTRIMLEFT:
 572                 for (loc = startp; loc < str; loc++) {
 573                         c = *loc;
 574                         *loc = '\0';
 575                         if (patmatch(str, startp, quotes)) {
 576                                 *loc = c;
 577                                 goto recordleft;
 578                         }
 579                         *loc = c;
 580                         if (quotes && *loc == CTLESC)
 581                                 loc++;
 582                 }
 583                 return 0;
 584
 585         case VSTRIMLEFTMAX:
 586                 for (loc = str - 1; loc >= startp;) {
 587                         c = *loc;
 588                         *loc = '\0';
 589                         if (patmatch(str, startp, quotes)) {
 590                                 *loc = c;
 591                                 goto recordleft;
 592                         }
 593                         *loc = c;
 594                         loc--;
 595                         if (quotes && loc > startp && *(loc - 1) == CTLESC) {
 596                                 for (q = startp; q < loc; q++)
 597                                         if (*q == CTLESC)
 598                                                 q++;
 599                                 if (q > loc)
 600                                         loc--;
 601                         }
 602                 }
 603                 return 0;
 604
 605         case VSTRIMRIGHT:
 606                 for (loc = str - 1; loc >= startp;) {
 607                         if (patmatch(str, loc, quotes)) {
 608                                 amount = loc - expdest;
 609                                 STADJUST(amount, expdest);
 610                                 return 1;
 611                         }
 612                         loc--;
 613                         if (quotes && loc > startp && *(loc - 1) == CTLESC) {
 614                                 for (q = startp; q < loc; q++)
 615                                         if (*q == CTLESC)
 616                                                 q++;
 617                                 if (q > loc)
 618                                         loc--;
 619                         }
 620                 }
 621                 return 0;
 622
 623         case VSTRIMRIGHTMAX:
 624                 for (loc = startp; loc < str - 1; loc++) {
 625                         if (patmatch(str, loc, quotes)) {
 626                                 amount = loc - expdest;
 627                                 STADJUST(amount, expdest);
 628                                 return 1;
 629                         }
 630                         if (quotes && *loc == CTLESC)
 631                                 loc++;
 632                 }
 633                 return 0;
 634
 635
 636         default:
 637                 abort();
 638         }
 639
 640 recordleft:
 641         amount = ((str - 1) - (loc - startp)) - expdest;
 642         STADJUST(amount, expdest);
 643         while (loc != str - 1)
 644                 *startp++ = *loc++;
 645         return 1;
 646 }
 647
 648
 649 /*
 650  * Expand a variable, and return a pointer to the next character in the
 651  * input string.
 652  */
 653
 654 static char *
 655 evalvar(char *p, int flag)
 656 {
 657         int subtype;
 658         int varflags;
 659         char *var;
 660         char *val;
 661         int patloc;
 662         int c;
 663         int set;
 664         int special;
 665         int startloc;
 666         int varlen;
 667         int varlenb;
 668         int easy;
 669         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 670
 671         varflags = (unsigned char)*p++;
 672         subtype = varflags & VSTYPE;
 673         var = p;
 674         special = 0;
 675         if (! is_name(*p))
 676                 special = 1;
 677         p = strchr(p, '=') + 1;
 678 again: /* jump here after setting a variable with ${var=text} */
 679         if (varflags & VSLINENO) {
 680                 set = 1;
 681                 special = 0;
 682                 val = var;
 683                 p[-1] = '\0';   /* temporarily overwrite '=' to have \0
 684                                    terminated string */
 685         } else if (special) {
 686                 set = varisset(var, varflags & VSNUL);
 687                 val = NULL;
 688         } else {
 689                 val = bltinlookup(var, 1);
 690                 if (val == NULL || ((varflags & VSNUL) && val[0] == '\0')) {
 691                         val = NULL;
 692                         set = 0;
 693                 } else
 694                         set = 1;
 695         }
 696         varlen = 0;
 697         startloc = expdest - stackblock();
 698         if (!set && uflag && *var != '@' && *var != '*') {
 699                 switch (subtype) {
 700                 case VSNORMAL:
 701                 case VSTRIMLEFT:
 702                 case VSTRIMLEFTMAX:
 703                 case VSTRIMRIGHT:
 704                 case VSTRIMRIGHTMAX:
 705                 case VSLENGTH:
 706                         error("%.*s: parameter not set", (int)(p - var - 1),
 707                             var);
 708                 }
 709         }
 710         if (set && subtype != VSPLUS) {
 711                 /* insert the value of the variable */
 712                 if (special) {
 713                         varvalue(var, varflags & VSQUOTE, subtype, flag);
 714                         if (subtype == VSLENGTH) {
 715                                 varlenb = expdest - stackblock() - startloc;
 716                                 varlen = varlenb;
 717                                 if (localeisutf8) {
 718                                         val = stackblock() + startloc;
 719                                         for (;val != expdest; val++)
 720                                                 if ((*val & 0xC0) == 0x80)
 721                                                         varlen--;
 722                                 }
 723                                 STADJUST(-varlenb, expdest);
 724                         }
 725                 } else {
 726                         char const *syntax = (varflags & VSQUOTE) ? DQSYNTAX
 727                                                                   : BASESYNTAX;
 728
 729                         if (subtype == VSLENGTH) {
 730                                 for (;*val; val++)
 731                                         if (!localeisutf8 ||
 732                                             (*val & 0xC0) != 0x80)
 733                                                 varlen++;
 734                         }
 735                         else {
 736                                 if (quotes)
 737                                         STPUTS_QUOTES(val, syntax, expdest);
 738                                 else
 739                                         STPUTS(val, expdest);
 740
 741                         }
 742                 }
 743         }
 744
 745         if (subtype == VSPLUS)
 746                 set = ! set;
 747
 748         easy = ((varflags & VSQUOTE) == 0 ||
 749                 (*var == '@' && shellparam.nparam != 1));
 750
 751
 752         switch (subtype) {
 753         case VSLENGTH:
 754                 expdest = cvtnum(varlen, expdest);
 755                 goto record;
 756
 757         case VSNORMAL:
 758                 if (!easy)
 759                         break;
 760 record:
 761                 recordregion(startloc, expdest - stackblock(),
 762                              varflags & VSQUOTE);
 763                 break;
 764
 765         case VSPLUS:
 766         case VSMINUS:
 767                 if (!set) {
 768                         argstr(p, flag | (flag & EXP_FULL ? EXP_SPLIT_LIT : 0) |
 769                             (varflags & VSQUOTE ? EXP_LIT_QUOTED : 0));
 770                         break;
 771                 }
 772                 if (easy)
 773                         goto record;
 774                 break;
 775
 776         case VSTRIMLEFT:
 777         case VSTRIMLEFTMAX:
 778         case VSTRIMRIGHT:
 779         case VSTRIMRIGHTMAX:
 780                 if (!set)
 781                         break;
 782                 /*
 783                  * Terminate the string and start recording the pattern
 784                  * right after it
 785                  */
 786                 STPUTC('\0', expdest);
 787                 patloc = expdest - stackblock();
 788                 if (subevalvar(p, NULL, patloc, subtype,
 789                     startloc, varflags, quotes) == 0) {
 790                         int amount = (expdest - stackblock() - patloc) + 1;
 791                         STADJUST(-amount, expdest);
 792                 }
 793                 /* Remove any recorded regions beyond start of variable */
 794                 removerecordregions(startloc);
 795                 goto record;
 796
 797         case VSASSIGN:
 798         case VSQUESTION:
 799                 if (!set) {
 800                         if (subevalvar(p, var, 0, subtype, startloc, varflags,
 801                             quotes)) {
 802                                 varflags &= ~VSNUL;
 803                                 /*
 804                                  * Remove any recorded regions beyond
 805                                  * start of variable
 806                                  */
 807                                 removerecordregions(startloc);
 808                                 goto again;
 809                         }
 810                         break;
 811                 }
 812                 if (easy)
 813                         goto record;
 814                 break;
 815
 816         case VSERROR:
 817                 c = p - var - 1;
 818                 error("${%.*s%s}: Bad substitution", c, var,
 819                     (c > 0 && *p != CTLENDVAR) ? "..." : "");
 820
 821         default:
 822                 abort();
 823         }
 824         p[-1] = '=';    /* recover overwritten '=' */
 825
 826         if (subtype != VSNORMAL) {      /* skip to end of alternative */
 827                 int nesting = 1;
 828                 for (;;) {
 829                         if ((c = *p++) == CTLESC)
 830                                 p++;
 831                         else if (c == CTLBACKQ || c == (CTLBACKQ|CTLQUOTE)) {
 832                                 if (set)
 833                                         argbackq = argbackq->next;
 834                         } else if (c == CTLVAR) {
 835                                 if ((*p++ & VSTYPE) != VSNORMAL)
 836                                         nesting++;
 837                         } else if (c == CTLENDVAR) {
 838                                 if (--nesting == 0)
 839                                         break;
 840                         }
 841                 }
 842         }
 843         return p;
 844 }
 845
 846
 847
 848 /*
 849  * Test whether a specialized variable is set.
 850  */
 851
 852 static int
 853 varisset(char *name, int nulok)
 854 {
 855
 856         if (*name == '!')
 857                 return backgndpidset();
 858         else if (*name == '@' || *name == '*') {
 859                 if (*shellparam.p == NULL)
 860                         return 0;
 861
 862                 if (nulok) {
 863                         char **av;
 864
 865                         for (av = shellparam.p; *av; av++)
 866                                 if (**av != '\0')
 867                                         return 1;
 868                         return 0;
 869                 }
 870         } else if (is_digit(*name)) {
 871                 char *ap;
 872                 int num = atoi(name);
 873
 874                 if (num > shellparam.nparam)
 875                         return 0;
 876
 877                 if (num == 0)
 878                         ap = arg0;
 879                 else
 880                         ap = shellparam.p[num - 1];
 881
 882                 if (nulok && (ap == NULL || *ap == '\0'))
 883                         return 0;
 884         }
 885         return 1;
 886 }
 887
 888 static void
 889 strtodest(const char *p, int flag, int subtype, int quoted)
 890 {
 891         if (flag & (EXP_FULL | EXP_CASE) && subtype != VSLENGTH)
 892                 STPUTS_QUOTES(p, quoted ? DQSYNTAX : BASESYNTAX, expdest);
 893         else
 894                 STPUTS(p, expdest);
 895 }
 896
 897 /*
 898  * Add the value of a specialized variable to the stack string.
 899  */
 900
 901 static void
 902 varvalue(char *name, int quoted, int subtype, int flag)
 903 {
 904         int num;
 905         char *p;
 906         int i;
 907         char sep;
 908         char **ap;
 909
 910         switch (*name) {
 911         case '$':
 912                 num = rootpid;
 913                 goto numvar;
 914         case '?':
 915                 num = oexitstatus;
 916                 goto numvar;
 917         case '#':
 918                 num = shellparam.nparam;
 919                 goto numvar;
 920         case '!':
 921                 num = backgndpidval();
 922 numvar:
 923                 expdest = cvtnum(num, expdest);
 924                 break;
 925         case '-':
 926                 for (i = 0 ; i < NOPTS ; i++) {
 927                         if (optlist[i].val)
 928                                 STPUTC(optlist[i].letter, expdest);
 929                 }
 930                 break;
 931         case '@':
 932                 if (flag & EXP_FULL && quoted) {
 933                         for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
 934                                 strtodest(p, flag, subtype, quoted);
 935                                 if (*ap)
 936                                         STPUTC('\0', expdest);
 937                         }
 938                         break;
 939                 }
 940                 /* FALLTHROUGH */
 941         case '*':
 942                 if (ifsset())
 943                         sep = ifsval()[0];
 944                 else
 945                         sep = ' ';
 946                 for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
 947                         strtodest(p, flag, subtype, quoted);
 948                         if (*ap && sep)
 949                                 STPUTC(sep, expdest);
 950                 }
 951                 break;
 952         case '0':
 953                 p = arg0;
 954                 strtodest(p, flag, subtype, quoted);
 955                 break;
 956         default:
 957                 if (is_digit(*name)) {
 958                         num = atoi(name);
 959                         if (num > 0 && num <= shellparam.nparam) {
 960                                 p = shellparam.p[num - 1];
 961                                 strtodest(p, flag, subtype, quoted);
 962                         }
 963                 }
 964                 break;
 965         }
 966 }
 967
 968
 969
 970 /*
 971  * Record the fact that we have to scan this region of the
 972  * string for IFS characters.
 973  */
 974
 975 static void
 976 recordregion(int start, int end, int inquotes)
 977 {
 978         struct ifsregion *ifsp;
 979
 980         if (ifslastp == NULL) {
 981                 ifsp = &ifsfirst;
 982         } else {
 983                 if (ifslastp->endoff == start
 984                     && ifslastp->inquotes == inquotes) {
 985                         /* extend previous area */
 986                         ifslastp->endoff = end;
 987                         return;
 988                 }
 989                 ifsp = (struct ifsregion *)ckmalloc(sizeof (struct ifsregion));
 990                 ifslastp->next = ifsp;
 991         }
 992         ifslastp = ifsp;
 993         ifslastp->next = NULL;
 994         ifslastp->begoff = start;
 995         ifslastp->endoff = end;
 996         ifslastp->inquotes = inquotes;
 997 }
 998
 999
1000
1001 /*
1002  * Break the argument string into pieces based upon IFS and add the
1003  * strings to the argument list.  The regions of the string to be
1004  * searched for IFS characters have been stored by recordregion.
1005  * CTLESC characters are preserved but have little effect in this pass
1006  * other than escaping CTL* characters.  In particular, they do not escape
1007  * IFS characters: that should be done with the ifsregion mechanism.
1008  * CTLQUOTEMARK characters are used to preserve empty quoted strings.
1009  * This pass treats them as a regular character, making the string non-empty.
1010  * Later, they are removed along with the other CTL* characters.
1011  */
1012 static void
1013 ifsbreakup(char *string, struct arglist *arglist)
1014 {
1015         struct ifsregion *ifsp;
1016         struct strlist *sp;
1017         char *start;
1018         char *p;
1019         char *q;
1020         const char *ifs;
1021         const char *ifsspc;
1022         int had_param_ch = 0;
1023
1024         start = string;
1025
1026         if (ifslastp == NULL) {
1027                 /* Return entire argument, IFS doesn't apply to any of it */
1028                 sp = (struct strlist *)stalloc(sizeof *sp);
1029                 sp->text = start;
1030                 *arglist->lastp = sp;
1031                 arglist->lastp = &sp->next;
1032                 return;
1033         }
1034
1035         ifs = ifsset() ? ifsval() : " \t\n";
1036
1037         for (ifsp = &ifsfirst; ifsp != NULL; ifsp = ifsp->next) {
1038                 p = string + ifsp->begoff;
1039                 while (p < string + ifsp->endoff) {
1040                         q = p;
1041                         if (*p == CTLESC)
1042                                 p++;
1043                         if (ifsp->inquotes) {
1044                                 /* Only NULs (should be from "$@") end args */
1045                                 had_param_ch = 1;
1046                                 if (*p != 0) {
1047                                         p++;
1048                                         continue;
1049                                 }
1050                                 ifsspc = NULL;
1051                         } else {
1052                                 if (!strchr(ifs, *p)) {
1053                                         had_param_ch = 1;
1054                                         p++;
1055                                         continue;
1056                                 }
1057                                 ifsspc = strchr(" \t\n", *p);
1058
1059                                 /* Ignore IFS whitespace at start */
1060                                 if (q == start && ifsspc != NULL) {
1061                                         p++;
1062                                         start = p;
1063                                         continue;
1064                                 }
1065                                 had_param_ch = 0;
1066                         }
1067
1068                         /* Save this argument... */
1069                         *q = '\0';
1070                         sp = (struct strlist *)stalloc(sizeof *sp);
1071                         sp->text = start;
1072                         *arglist->lastp = sp;
1073                         arglist->lastp = &sp->next;
1074                         p++;
1075
1076                         if (ifsspc != NULL) {
1077                                 /* Ignore further trailing IFS whitespace */
1078                                 for (; p < string + ifsp->endoff; p++) {
1079                                         q = p;
1080                                         if (*p == CTLESC)
1081                                                 p++;
1082                                         if (strchr(ifs, *p) == NULL) {
1083                                                 p = q;
1084                                                 break;
1085                                         }
1086                                         if (strchr(" \t\n", *p) == NULL) {
1087                                                 p++;
1088                                                 break;
1089                                         }
1090                                 }
1091                         }
1092                         start = p;
1093                 }
1094         }
1095
1096         /*
1097          * Save anything left as an argument.
1098          * Traditionally we have treated 'IFS=':'; set -- x$IFS' as
1099          * generating 2 arguments, the second of which is empty.
1100          * Some recent clarification of the Posix spec say that it
1101          * should only generate one....
1102          */
1103         if (had_param_ch || *start != 0) {
1104                 sp = (struct strlist *)stalloc(sizeof *sp);
1105                 sp->text = start;
1106                 *arglist->lastp = sp;
1107                 arglist->lastp = &sp->next;
1108         }
1109 }
1110
1111
1112 static char expdir[PATH_MAX];
1113 #define expdir_end (expdir + sizeof(expdir))
1114
1115 /*
1116  * Perform pathname generation and remove control characters.
1117  * At this point, the only control characters should be CTLESC and CTLQUOTEMARK.
1118  * The results are stored in the list exparg.
1119  */
1120 static void
1121 expandmeta(struct strlist *str, int flag __unused)
1122 {
1123         char *p;
1124         struct strlist **savelastp;
1125         struct strlist *sp;
1126         char c;
1127         /* TODO - EXP_REDIR */
1128
1129         while (str) {
1130                 if (fflag)
1131                         goto nometa;
1132                 p = str->text;
1133                 for (;;) {                      /* fast check for meta chars */
1134                         if ((c = *p++) == '\0')
1135                                 goto nometa;
1136                         if (c == '*' || c == '?' || c == '[')
1137                                 break;
1138                 }
1139                 savelastp = exparg.lastp;
1140                 INTOFF;
1141                 expmeta(expdir, str->text);
1142                 INTON;
1143                 if (exparg.lastp == savelastp) {
1144                         /*
1145                          * no matches
1146                          */
1147 nometa:
1148                         *exparg.lastp = str;
1149                         rmescapes(str->text);
1150                         exparg.lastp = &str->next;
1151                 } else {
1152                         *exparg.lastp = NULL;
1153                         *savelastp = sp = expsort(*savelastp);
1154                         while (sp->next != NULL)
1155                                 sp = sp->next;
1156                         exparg.lastp = &sp->next;
1157                 }
1158                 str = str->next;
1159         }
1160 }
1161
1162
1163 /*
1164  * Do metacharacter (i.e. *, ?, [...]) expansion.
1165  */
1166
1167 static void
1168 expmeta(char *enddir, char *name)
1169 {
1170         char *p;
1171         char *q;
1172         char *start;
1173         char *endname;
1174         int metaflag;
1175         struct stat statb;
1176         DIR *dirp;
1177         struct dirent *dp;
1178         int atend;
1179         int matchdot;
1180         int esc;
1181
1182         metaflag = 0;
1183         start = name;
1184         for (p = name; esc = 0, *p; p += esc + 1) {
1185                 if (*p == '*' || *p == '?')
1186                         metaflag = 1;
1187                 else if (*p == '[') {
1188                         q = p + 1;
1189                         if (*q == '!' || *q == '^')
1190                                 q++;
1191                         for (;;) {
1192                                 while (*q == CTLQUOTEMARK)
1193                                         q++;
1194                                 if (*q == CTLESC)
1195                                         q++;
1196                                 if (*q == '/' || *q == '\0')
1197                                         break;
1198                                 if (*++q == ']') {
1199                                         metaflag = 1;
1200                                         break;
1201                                 }
1202                         }
1203                 } else if (*p == '\0')
1204                         break;
1205                 else if (*p == CTLQUOTEMARK)
1206                         continue;
1207                 else {
1208                         if (*p == CTLESC)
1209                                 esc++;
1210                         if (p[esc] == '/') {
1211                                 if (metaflag)
1212                                         break;
1213                                 start = p + esc + 1;
1214                         }
1215                 }
1216         }
1217         if (metaflag == 0) {    /* we've reached the end of the file name */
1218                 if (enddir != expdir)
1219                         metaflag++;
1220                 for (p = name ; ; p++) {
1221                         if (*p == CTLQUOTEMARK)
1222                                 continue;
1223                         if (*p == CTLESC)
1224                                 p++;
1225                         *enddir++ = *p;
1226                         if (*p == '\0')
1227                                 break;
1228                         if (enddir == expdir_end)
1229                                 return;
1230                 }
1231                 if (metaflag == 0 || lstat(expdir, &statb) >= 0)
1232                         addfname(expdir);
1233                 return;
1234         }
1235         endname = p;
1236         if (start != name) {
1237                 p = name;
1238                 while (p < start) {
1239                         while (*p == CTLQUOTEMARK)
1240                                 p++;
1241                         if (*p == CTLESC)
1242                                 p++;
1243                         *enddir++ = *p++;
1244                         if (enddir == expdir_end)
1245                                 return;
1246                 }
1247         }
1248         if (enddir == expdir) {
1249                 p = __DECONST(char *, ".");
1250         } else if (enddir == expdir + 1 && *expdir == '/') {
1251                 p = __DECONST(char *, "/");
1252         } else {
1253                 p = expdir;
1254                 enddir[-1] = '\0';
1255         }
1256         if ((dirp = opendir(p)) == NULL)
1257                 return;
1258         if (enddir != expdir)
1259                 enddir[-1] = '/';
1260         if (*endname == 0) {
1261                 atend = 1;
1262         } else {
1263                 atend = 0;
1264                 *endname = '\0';
1265                 endname += esc + 1;
1266         }
1267         matchdot = 0;
1268         p = start;
1269         while (*p == CTLQUOTEMARK)
1270                 p++;
1271         if (*p == CTLESC)
1272                 p++;
1273         if (*p == '.')
1274                 matchdot++;
1275         while (! int_pending() && (dp = readdir(dirp)) != NULL) {
1276                 if (dp->d_name[0] == '.' && ! matchdot)
1277                         continue;
1278                 if (patmatch(start, dp->d_name, 0)) {
1279                         if (enddir + dp->d_namlen + 1 > expdir_end)
1280                                 continue;
1281                         memcpy(enddir, dp->d_name, dp->d_namlen + 1);
1282                         if (atend)
1283                                 addfname(expdir);
1284                         else {
1285                                 if (enddir + dp->d_namlen + 2 > expdir_end)
1286                                         continue;
1287                                 enddir[dp->d_namlen] = '/';
1288                                 enddir[dp->d_namlen + 1] = '\0';
1289                                 expmeta(enddir + dp->d_namlen + 1, endname);
1290                         }
1291                 }
1292         }
1293         closedir(dirp);
1294         if (! atend)
1295                 endname[-esc - 1] = esc ? CTLESC : '/';
1296 }
1297
1298
1299 /*
1300  * Add a file name to the list.
1301  */
1302
1303 static void
1304 addfname(char *name)
1305 {
1306         char *p;
1307         struct strlist *sp;
1308
1309         p = stalloc(strlen(name) + 1);
1310         scopy(name, p);
1311         sp = (struct strlist *)stalloc(sizeof *sp);
1312         sp->text = p;
1313         *exparg.lastp = sp;
1314         exparg.lastp = &sp->next;
1315 }
1316
1317
1318 /*
1319  * Sort the results of file name expansion.  It calculates the number of
1320  * strings to sort and then calls msort (short for merge sort) to do the
1321  * work.
1322  */
1323
1324 static struct strlist *
1325 expsort(struct strlist *str)
1326 {
1327         int len;
1328         struct strlist *sp;
1329
1330         len = 0;
1331         for (sp = str ; sp ; sp = sp->next)
1332                 len++;
1333         return msort(str, len);
1334 }
1335
1336
1337 static struct strlist *
1338 msort(struct strlist *list, int len)
1339 {
1340         struct strlist *p, *q = NULL;
1341         struct strlist **lpp;
1342         int half;
1343         int n;
1344
1345         if (len <= 1)
1346                 return list;
1347         half = len >> 1;
1348         p = list;
1349         for (n = half ; --n >= 0 ; ) {
1350                 q = p;
1351                 p = p->next;
1352         }
1353         q->next = NULL;                 /* terminate first half of list */
1354         q = msort(list, half);          /* sort first half of list */
1355         p = msort(p, len - half);               /* sort second half */
1356         lpp = &list;
1357         for (;;) {
1358                 if (strcmp(p->text, q->text) < 0) {
1359                         *lpp = p;
1360                         lpp = &p->next;
1361                         if ((p = *lpp) == NULL) {
1362                                 *lpp = q;
1363                                 break;
1364                         }
1365                 } else {
1366                         *lpp = q;
1367                         lpp = &q->next;
1368                         if ((q = *lpp) == NULL) {
1369                                 *lpp = p;
1370                                 break;
1371                         }
1372                 }
1373         }
1374         return list;
1375 }
1376
1377
1378
1379 /*
1380  * Returns true if the pattern matches the string.
1381  */
1382
1383 int
1384 patmatch(const char *pattern, const char *string, int squoted)
1385 {
1386         const char *p, *q;
1387         char c;
1388
1389         p = pattern;
1390         q = string;
1391         for (;;) {
1392                 switch (c = *p++) {
1393                 case '\0':
1394                         goto breakloop;
1395                 case CTLESC:
1396                         if (squoted && *q == CTLESC)
1397                                 q++;
1398                         if (*q++ != *p++)
1399                                 return 0;
1400                         break;
1401                 case CTLQUOTEMARK:
1402                         continue;
1403                 case '?':
1404                         if (squoted && *q == CTLESC)
1405                                 q++;
1406                         if (*q++ == '\0')
1407                                 return 0;
1408                         break;
1409                 case '*':
1410                         c = *p;
1411                         while (c == CTLQUOTEMARK || c == '*')
1412                                 c = *++p;
1413                         if (c != CTLESC &&  c != CTLQUOTEMARK &&
1414                             c != '?' && c != '*' && c != '[') {
1415                                 while (*q != c) {
1416                                         if (squoted && *q == CTLESC &&
1417                                             q[1] == c)
1418                                                 break;
1419                                         if (*q == '\0')
1420                                                 return 0;
1421                                         if (squoted && *q == CTLESC)
1422                                                 q++;
1423                                         q++;
1424                                 }
1425                         }
1426                         do {
1427                                 if (patmatch(p, q, squoted))
1428                                         return 1;
1429                                 if (squoted && *q == CTLESC)
1430                                         q++;
1431                         } while (*q++ != '\0');
1432                         return 0;
1433                 case '[': {
1434                         const char *endp;
1435                         int invert, found;
1436                         char chr;
1437
1438                         endp = p;
1439                         if (*endp == '!' || *endp == '^')
1440                                 endp++;
1441                         for (;;) {
1442                                 while (*endp == CTLQUOTEMARK)
1443                                         endp++;
1444                                 if (*endp == '\0')
1445                                         goto dft;               /* no matching ] */
1446                                 if (*endp == CTLESC)
1447                                         endp++;
1448                                 if (*++endp == ']')
1449                                         break;
1450                         }
1451                         invert = 0;
1452                         if (*p == '!' || *p == '^') {
1453                                 invert++;
1454                                 p++;
1455                         }
1456                         found = 0;
1457                         chr = *q++;
1458                         if (squoted && chr == CTLESC)
1459                                 chr = *q++;
1460                         if (chr == '\0')
1461                                 return 0;
1462                         c = *p++;
1463                         do {
1464                                 if (c == CTLQUOTEMARK)
1465                                         continue;
1466                                 if (c == CTLESC)
1467                                         c = *p++;
1468                                 if (*p == '-' && p[1] != ']') {
1469                                         p++;
1470                                         while (*p == CTLQUOTEMARK)
1471                                                 p++;
1472                                         if (*p == CTLESC)
1473                                                 p++;
1474                                         if (   collate_range_cmp(chr, c) >= 0
1475                                             && collate_range_cmp(chr, *p) <= 0
1476                                            )
1477                                                 found = 1;
1478                                         p++;
1479                                 } else {
1480                                         if (chr == c)
1481                                                 found = 1;
1482                                 }
1483                         } while ((c = *p++) != ']');
1484                         if (found == invert)
1485                                 return 0;
1486                         break;
1487                 }
1488 dft:            default:
1489                         if (squoted && *q == CTLESC)
1490                                 q++;
1491                         if (*q++ != c)
1492                                 return 0;
1493                         break;
1494                 }
1495         }
1496 breakloop:
1497         if (*q != '\0')
1498                 return 0;
1499         return 1;
1500 }
1501
1502
1503
1504 /*
1505  * Remove any CTLESC and CTLQUOTEMARK characters from a string.
1506  */
1507
1508 void
1509 rmescapes(char *str)
1510 {
1511         char *p, *q;
1512
1513         p = str;
1514         while (*p != CTLESC && *p != CTLQUOTEMARK && *p != CTLQUOTEEND) {
1515                 if (*p++ == '\0')
1516                         return;
1517         }
1518         q = p;
1519         while (*p) {
1520                 if (*p == CTLQUOTEMARK || *p == CTLQUOTEEND) {
1521                         p++;
1522                         continue;
1523                 }
1524                 if (*p == CTLESC)
1525                         p++;
1526                 *q++ = *p++;
1527         }
1528         *q = '\0';
1529 }
1530
1531
1532
1533 /*
1534  * See if a pattern matches in a case statement.
1535  */
1536
1537 int
1538 casematch(union node *pattern, const char *val)
1539 {
1540         struct stackmark smark;
1541         int result;
1542         char *p;
1543
1544         setstackmark(&smark);
1545         argbackq = pattern->narg.backquote;
1546         STARTSTACKSTR(expdest);
1547         ifslastp = NULL;
1548         argstr(pattern->narg.text, EXP_TILDE | EXP_CASE);
1549         STPUTC('\0', expdest);
1550         p = grabstackstr(expdest);
1551         result = patmatch(p, val, 0);
1552         popstackmark(&smark);
1553         return result;
1554 }
1555
1556 /*
1557  * Our own itoa().
1558  */
1559
1560 static char *
1561 cvtnum(int num, char *buf)
1562 {
1563         char temp[32];
1564         int neg = num < 0;
1565         char *p = temp + 31;
1566
1567         temp[31] = '\0';
1568
1569         do {
1570                 *--p = num % 10 + '0';
1571         } while ((num /= 10) != 0);
1572
1573         if (neg)
1574                 *--p = '-';
1575
1576         STPUTS(p, buf);
1577         return buf;
1578 }
1579
1580 /*
1581  * Check statically if expanding a string may have side effects.
1582  */
1583 int
1584 expandhassideeffects(const char *p)
1585 {
1586         int c;
1587         int arinest;
1588
1589         arinest = 0;
1590         while ((c = *p++) != '\0') {
1591                 switch (c) {
1592                 case CTLESC:
1593                         p++;
1594                         break;
1595                 case CTLVAR:
1596                         c = *p++;
1597                         /* Expanding $! sets the job to remembered. */
1598                         if (*p == '!')
1599                                 return 1;
1600                         if ((c & VSTYPE) == VSASSIGN)
1601                                 return 1;
1602                         /*
1603                          * If we are in arithmetic, the parameter may contain
1604                          * '=' which may cause side effects. Exceptions are
1605                          * the length of a parameter and $$, $# and $? which
1606                          * are always numeric.
1607                          */
1608                         if ((c & VSTYPE) == VSLENGTH) {
1609                                 while (*p != '=')
1610                                         p++;
1611                                 p++;
1612                                 break;
1613                         }
1614                         if ((*p == '$' || *p == '#' || *p == '?') &&
1615                             p[1] == '=') {
1616                                 p += 2;
1617                                 break;
1618                         }
1619                         if (arinest > 0)
1620                                 return 1;
1621                         break;
1622                 case CTLBACKQ:
1623                 case CTLBACKQ | CTLQUOTE:
1624                         if (arinest > 0)
1625                                 return 1;
1626                         break;
1627                 case CTLARI:
1628                         arinest++;
1629                         break;
1630                 case CTLENDARI:
1631                         arinest--;
1632                         break;
1633                 case '=':
1634                         if (*p == '=') {
1635                                 /* Allow '==' operator. */
1636                                 p++;
1637                                 continue;
1638                         }
1639                         if (arinest > 0)
1640                                 return 1;
1641                         break;
1642                 case '!': case '<': case '>':
1643                         /* Allow '!=', '<=', '>=' operators. */
1644                         if (*p == '=')
1645                                 p++;
1646                         break;
1647                 }
1648         }
1649         return 0;
1650 }
1651
1652 /*
1653  * Do most of the work for wordexp(3).
1654  */
1655
1656 int
1657 wordexpcmd(int argc, char **argv)
1658 {
1659         size_t len;
1660         int i;
1661
1662         out1fmt("%08x", argc - 1);
1663         for (i = 1, len = 0; i < argc; i++)
1664                 len += strlen(argv[i]);
1665         out1fmt("%08x", (int)len);
1666         for (i = 1; i < argc; i++)
1667                 outbin(argv[i], strlen(argv[i]) + 1, out1);
1668         return (0);
1669 }