bin/sh/expand.c

   1 /*-
   2  * Copyright (c) 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Kenneth Almquist.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * @(#)expand.c 8.5 (Berkeley) 5/15/95
  37  * $FreeBSD: src/bin/sh/expand.c,v 1.51 2006/11/07 22:46:13 stefanf Exp $
  38  * $DragonFly: src/bin/sh/expand.c,v 1.9 2007/01/07 16:58:30 pavalos Exp $
  39  */
  40
  41 #include <sys/types.h>
  42 #include <sys/time.h>
  43 #include <sys/stat.h>
  44 #include <errno.h>
  45 #include <dirent.h>
  46 #include <unistd.h>
  47 #include <pwd.h>
  48 #include <stdlib.h>
  49 #include <limits.h>
  50 #include <stdio.h>
  51 #include <string.h>
  52
  53 /*
  54  * Routines to expand arguments to commands.  We have to deal with
  55  * backquotes, shell variables, and file metacharacters.
  56  */
  57
  58 #include "shell.h"
  59 #include "main.h"
  60 #include "nodes.h"
  61 #include "eval.h"
  62 #include "expand.h"
  63 #include "syntax.h"
  64 #include "parser.h"
  65 #include "jobs.h"
  66 #include "options.h"
  67 #include "var.h"
  68 #include "input.h"
  69 #include "output.h"
  70 #include "memalloc.h"
  71 #include "error.h"
  72 #include "mystring.h"
  73 #include "arith.h"
  74 #include "show.h"
  75
  76 /*
  77  * Structure specifying which parts of the string should be searched
  78  * for IFS characters.
  79  */
  80
  81 struct ifsregion {
  82         struct ifsregion *next; /* next region in list */
  83         int begoff;             /* offset of start of region */
  84         int endoff;             /* offset of end of region */
  85         int nulonly;            /* search for nul bytes only */
  86 };
  87
  88
  89 STATIC char *expdest;                   /* output of current string */
  90 STATIC struct nodelist *argbackq;       /* list of back quote expressions */
  91 STATIC struct ifsregion ifsfirst;       /* first struct in list of ifs regions */
  92 STATIC struct ifsregion *ifslastp;      /* last struct in list */
  93 STATIC struct arglist exparg;           /* holds expanded arg list */
  94
  95 STATIC void argstr(char *, int);
  96 STATIC char *exptilde(char *, int);
  97 STATIC void expbackq(union node *, int, int);
  98 STATIC int subevalvar(char *, char *, int, int, int, int);
  99 STATIC char *evalvar(char *, int);
 100 STATIC int varisset(char *, int);
 101 STATIC void varvalue(char *, int, int, int);
 102 STATIC void recordregion(int, int, int);
 103 STATIC void removerecordregions(int);
 104 STATIC void ifsbreakup(char *, struct arglist *);
 105 STATIC void expandmeta(struct strlist *, int);
 106 STATIC void expmeta(char *, char *);
 107 STATIC void addfname(char *);
 108 STATIC struct strlist *expsort(struct strlist *);
 109 STATIC struct strlist *msort(struct strlist *, int);
 110 STATIC int pmatch(char *, char *, int);
 111 STATIC char *cvtnum(int, char *);
 112 STATIC int collate_range_cmp(int, int);
 113
 114 STATIC int
 115 collate_range_cmp(int c1, int c2)
 116 {
 117         static char s1[2], s2[2];
 118
 119         s1[0] = c1;
 120         s2[0] = c2;
 121         return (strcoll(s1, s2));
 122 }
 123
 124 extern int oexitstatus;
 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, NULL, 0);
 137         xwrite(fd, stackblock(), expdest - stackblock());
 138 }
 139
 140
 141 /*
 142  * Perform variable substitution and command substitution on an argument,
 143  * placing the resulting list of arguments in arglist.  If EXP_FULL is true,
 144  * perform splitting and file name expansion.  When arglist is NULL, perform
 145  * here document expansion.
 146  */
 147
 148 void
 149 expandarg(union node *arg, struct arglist *arglist, int flag)
 150 {
 151         struct strlist *sp;
 152         char *p;
 153
 154         argbackq = arg->narg.backquote;
 155         STARTSTACKSTR(expdest);
 156         ifsfirst.next = NULL;
 157         ifslastp = NULL;
 158         argstr(arg->narg.text, flag);
 159         if (arglist == NULL) {
 160                 return;                 /* here document expanded */
 161         }
 162         STPUTC('\0', expdest);
 163         p = grabstackstr(expdest);
 164         exparg.lastp = &exparg.list;
 165         /*
 166          * TODO - EXP_REDIR
 167          */
 168         if (flag & EXP_FULL) {
 169                 ifsbreakup(p, &exparg);
 170                 *exparg.lastp = NULL;
 171                 exparg.lastp = &exparg.list;
 172                 expandmeta(exparg.list, flag);
 173         } else {
 174                 if (flag & EXP_REDIR) /*XXX - for now, just remove escapes */
 175                         rmescapes(p);
 176                 sp = (struct strlist *)stalloc(sizeof (struct strlist));
 177                 sp->text = p;
 178                 *exparg.lastp = sp;
 179                 exparg.lastp = &sp->next;
 180         }
 181         while (ifsfirst.next != NULL) {
 182                 struct ifsregion *ifsp;
 183                 INTOFF;
 184                 ifsp = ifsfirst.next->next;
 185                 ckfree(ifsfirst.next);
 186                 ifsfirst.next = ifsp;
 187                 INTON;
 188         }
 189         *exparg.lastp = NULL;
 190         if (exparg.list) {
 191                 *arglist->lastp = exparg.list;
 192                 arglist->lastp = exparg.lastp;
 193         }
 194 }
 195
 196
 197
 198 /*
 199  * Perform variable and command substitution.  If EXP_FULL is set, output CTLESC
 200  * characters to allow for further processing.  Otherwise treat
 201  * $@ like $* since no splitting will be performed.
 202  */
 203
 204 STATIC void
 205 argstr(char *p, int flag)
 206 {
 207         char c;
 208         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);  /* do CTLESC */
 209         int firsteq = 1;
 210
 211         if (*p == '~' && (flag & (EXP_TILDE | EXP_VARTILDE)))
 212                 p = exptilde(p, flag);
 213         for (;;) {
 214                 switch (c = *p++) {
 215                 case '\0':
 216                 case CTLENDVAR: /* ??? */
 217                         goto breakloop;
 218                 case CTLQUOTEMARK:
 219                         /* "$@" syntax adherence hack */
 220                         if (p[0] == CTLVAR && p[2] == '@' && p[3] == '=')
 221                                 break;
 222                         if ((flag & EXP_FULL) != 0)
 223                                 STPUTC(c, expdest);
 224                         break;
 225                 case CTLESC:
 226                         if (quotes)
 227                                 STPUTC(c, expdest);
 228                         c = *p++;
 229                         STPUTC(c, expdest);
 230                         break;
 231                 case CTLVAR:
 232                         p = evalvar(p, flag);
 233                         break;
 234                 case CTLBACKQ:
 235                 case CTLBACKQ|CTLQUOTE:
 236                         expbackq(argbackq->n, c & CTLQUOTE, flag);
 237                         argbackq = argbackq->next;
 238                         break;
 239                 case CTLENDARI:
 240                         expari(flag);
 241                         break;
 242                 case ':':
 243                 case '=':
 244                         /*
 245                          * sort of a hack - expand tildes in variable
 246                          * assignments (after the first '=' and after ':'s).
 247                          */
 248                         STPUTC(c, expdest);
 249                         if (flag & EXP_VARTILDE && *p == '~') {
 250                                 if (c == '=') {
 251                                         if (firsteq)
 252                                                 firsteq = 0;
 253                                         else
 254                                                 break;
 255                                 }
 256                                 p = exptilde(p, flag);
 257                         }
 258                         break;
 259                 default:
 260                         STPUTC(c, expdest);
 261                 }
 262         }
 263 breakloop:;
 264 }
 265
 266 STATIC char *
 267 exptilde(char *p, int flag)
 268 {
 269         char c, *startp = p;
 270         struct passwd *pw;
 271         char *home;
 272         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 273
 274         while ((c = *p) != '\0') {
 275                 switch(c) {
 276                 case CTLESC:
 277                         return (startp);
 278                 case CTLQUOTEMARK:
 279                         return (startp);
 280                 case ':':
 281                         if (flag & EXP_VARTILDE)
 282                                 goto done;
 283                         break;
 284                 case '/':
 285                         goto done;
 286                 }
 287                 p++;
 288         }
 289 done:
 290         *p = '\0';
 291         if (*(startp+1) == '\0') {
 292                 if ((home = lookupvar("HOME")) == NULL)
 293                         goto lose;
 294         } else {
 295                 if ((pw = getpwnam(startp+1)) == NULL)
 296                         goto lose;
 297                 home = pw->pw_dir;
 298         }
 299         if (*home == '\0')
 300                 goto lose;
 301         *p = c;
 302         while ((c = *home++) != '\0') {
 303                 if (quotes && SQSYNTAX[(int)c] == CCTL)
 304                         STPUTC(CTLESC, expdest);
 305                 STPUTC(c, expdest);
 306         }
 307         return (p);
 308 lose:
 309         *p = c;
 310         return (startp);
 311 }
 312
 313
 314 STATIC void
 315 removerecordregions(int endoff)
 316 {
 317         if (ifslastp == NULL)
 318                 return;
 319
 320         if (ifsfirst.endoff > endoff) {
 321                 while (ifsfirst.next != NULL) {
 322                         struct ifsregion *ifsp;
 323                         INTOFF;
 324                         ifsp = ifsfirst.next->next;
 325                         ckfree(ifsfirst.next);
 326                         ifsfirst.next = ifsp;
 327                         INTON;
 328                 }
 329                 if (ifsfirst.begoff > endoff)
 330                         ifslastp = NULL;
 331                 else {
 332                         ifslastp = &ifsfirst;
 333                         ifsfirst.endoff = endoff;
 334                 }
 335                 return;
 336         }
 337
 338         ifslastp = &ifsfirst;
 339         while (ifslastp->next && ifslastp->next->begoff < endoff)
 340                 ifslastp=ifslastp->next;
 341         while (ifslastp->next != NULL) {
 342                 struct ifsregion *ifsp;
 343                 INTOFF;
 344                 ifsp = ifslastp->next->next;
 345                 ckfree(ifslastp->next);
 346                 ifslastp->next = ifsp;
 347                 INTON;
 348         }
 349         if (ifslastp->endoff > endoff)
 350                 ifslastp->endoff = endoff;
 351 }
 352
 353 /*
 354  * Expand arithmetic expression.  Backup to start of expression,
 355  * evaluate, place result in (backed up) result, adjust string position.
 356  */
 357 void
 358 expari(int flag)
 359 {
 360         char *p, *start;
 361         int result;
 362         int begoff;
 363         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 364         int quoted;
 365
 366
 367         /*
 368          * This routine is slightly over-complicated for
 369          * efficiency.  First we make sure there is
 370          * enough space for the result, which may be bigger
 371          * than the expression if we add exponentiation.  Next we
 372          * scan backwards looking for the start of arithmetic.  If the
 373          * next previous character is a CTLESC character, then we
 374          * have to rescan starting from the beginning since CTLESC
 375          * characters have to be processed left to right.
 376          */
 377 #if INT_MAX / 1000000000 >= 10 || INT_MIN / 1000000000 <= -10
 378 #error "integers with more than 10 digits are not supported"
 379 #endif
 380         CHECKSTRSPACE(12 - 2, expdest);
 381         USTPUTC('\0', expdest);
 382         start = stackblock();
 383         p = expdest - 2;
 384         while (p >= start && *p != CTLARI)
 385                 --p;
 386         if (p < start || *p != CTLARI)
 387                 error("missing CTLARI (shouldn't happen)");
 388         if (p > start && *(p - 1) == CTLESC)
 389                 for (p = start; *p != CTLARI; p++)
 390                         if (*p == CTLESC)
 391                                 p++;
 392
 393         if (p[1] == '"')
 394                 quoted=1;
 395         else
 396                 quoted=0;
 397         begoff = p - start;
 398         removerecordregions(begoff);
 399         if (quotes)
 400                 rmescapes(p+2);
 401         result = arith(p+2);
 402         fmtstr(p, 12, "%d", result);
 403         while (*p++)
 404                 ;
 405         if (quoted == 0)
 406                 recordregion(begoff, p - 1 - start, 0);
 407         result = expdest - p + 1;
 408         STADJUST(-result, expdest);
 409 }
 410
 411
 412 /*
 413  * Expand stuff in backwards quotes.
 414  */
 415
 416 STATIC void
 417 expbackq(union node *cmd, int quoted, int flag)
 418 {
 419         struct backcmd in;
 420         int i;
 421         char buf[128];
 422         char *p;
 423         char *dest = expdest;
 424         struct ifsregion saveifs, *savelastp;
 425         struct nodelist *saveargbackq;
 426         char lastc;
 427         int startloc = dest - stackblock();
 428         char const *syntax = quoted? DQSYNTAX : BASESYNTAX;
 429         int saveherefd;
 430         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 431
 432         INTOFF;
 433         saveifs = ifsfirst;
 434         savelastp = ifslastp;
 435         saveargbackq = argbackq;
 436         saveherefd = herefd;
 437         herefd = -1;
 438         p = grabstackstr(dest);
 439         evalbackcmd(cmd, &in);
 440         ungrabstackstr(p, dest);
 441         ifsfirst = saveifs;
 442         ifslastp = savelastp;
 443         argbackq = saveargbackq;
 444         herefd = saveherefd;
 445
 446         p = in.buf;
 447         lastc = '\0';
 448         for (;;) {
 449                 if (--in.nleft < 0) {
 450                         if (in.fd < 0)
 451                                 break;
 452                         while ((i = read(in.fd, buf, sizeof buf)) < 0 && errno == EINTR);
 453                         TRACE(("expbackq: read returns %d\n", i));
 454                         if (i <= 0)
 455                                 break;
 456                         p = buf;
 457                         in.nleft = i - 1;
 458                 }
 459                 lastc = *p++;
 460                 if (lastc != '\0') {
 461                         if (quotes && syntax[(int)lastc] == CCTL)
 462                                 STPUTC(CTLESC, dest);
 463                         STPUTC(lastc, dest);
 464                 }
 465         }
 466
 467         /* Eat all trailing newlines */
 468         for ( ; (dest - stackblock()) > startloc && *(dest-1) == '\n'; )
 469                 STUNPUTC(dest);
 470
 471         if (in.fd >= 0)
 472                 close(in.fd);
 473         if (in.buf)
 474                 ckfree(in.buf);
 475         if (in.jp)
 476                 exitstatus = waitforjob(in.jp, NULL);
 477         if (quoted == 0)
 478                 recordregion(startloc, dest - stackblock(), 0);
 479         TRACE(("evalbackq: size=%d: \"%.*s\"\n",
 480                 (dest - stackblock()) - startloc,
 481                 (dest - stackblock()) - startloc,
 482                 stackblock() + startloc));
 483         expdest = dest;
 484         INTON;
 485 }
 486
 487
 488
 489 STATIC int
 490 subevalvar(char *p, char *str, int strloc, int subtype, int startloc,
 491   int varflags)
 492 {
 493         char *startp;
 494         char *loc = NULL;
 495         char *q;
 496         int c = 0;
 497         int saveherefd = herefd;
 498         struct nodelist *saveargbackq = argbackq;
 499         int amount;
 500
 501         herefd = -1;
 502         argstr(p, 0);
 503         STACKSTRNUL(expdest);
 504         herefd = saveherefd;
 505         argbackq = saveargbackq;
 506         startp = stackblock() + startloc;
 507         if (str == NULL)
 508             str = stackblock() + strloc;
 509
 510         switch (subtype) {
 511         case VSASSIGN:
 512                 setvar(str, startp, 0);
 513                 amount = startp - expdest;
 514                 STADJUST(amount, expdest);
 515                 varflags &= ~VSNUL;
 516                 if (c != 0)
 517                         *loc = c;
 518                 return 1;
 519
 520         case VSQUESTION:
 521                 if (*p != CTLENDVAR) {
 522                         outfmt(&errout, "%s\n", startp);
 523                         error(NULL);
 524                 }
 525                 error("%.*s: parameter %snot set", (int)(p - str - 1),
 526                       str, (varflags & VSNUL) ? "null or "
 527                                               : nullstr);
 528                 return 0;
 529
 530         case VSTRIMLEFT:
 531                 for (loc = startp; loc < str; loc++) {
 532                         c = *loc;
 533                         *loc = '\0';
 534                         if (patmatch(str, startp, varflags & VSQUOTE)) {
 535                                 *loc = c;
 536                                 goto recordleft;
 537                         }
 538                         *loc = c;
 539                         if ((varflags & VSQUOTE) && *loc == CTLESC)
 540                                 loc++;
 541                 }
 542                 return 0;
 543
 544         case VSTRIMLEFTMAX:
 545                 for (loc = str - 1; loc >= startp;) {
 546                         c = *loc;
 547                         *loc = '\0';
 548                         if (patmatch(str, startp, varflags & VSQUOTE)) {
 549                                 *loc = c;
 550                                 goto recordleft;
 551                         }
 552                         *loc = c;
 553                         loc--;
 554                         if ((varflags & VSQUOTE) && loc > startp &&
 555                             *(loc - 1) == CTLESC) {
 556                                 for (q = startp; q < loc; q++)
 557                                         if (*q == CTLESC)
 558                                                 q++;
 559                                 if (q > loc)
 560                                         loc--;
 561                         }
 562                 }
 563                 return 0;
 564
 565         case VSTRIMRIGHT:
 566                 for (loc = str - 1; loc >= startp;) {
 567                         if (patmatch(str, loc, varflags & VSQUOTE)) {
 568                                 amount = loc - expdest;
 569                                 STADJUST(amount, expdest);
 570                                 return 1;
 571                         }
 572                         loc--;
 573                         if ((varflags & VSQUOTE) && loc > startp &&
 574                             *(loc - 1) == CTLESC) {
 575                                 for (q = startp; q < loc; q++)
 576                                         if (*q == CTLESC)
 577                                                 q++;
 578                                 if (q > loc)
 579                                         loc--;
 580                         }
 581                 }
 582                 return 0;
 583
 584         case VSTRIMRIGHTMAX:
 585                 for (loc = startp; loc < str - 1; loc++) {
 586                         if (patmatch(str, loc, varflags & VSQUOTE)) {
 587                                 amount = loc - expdest;
 588                                 STADJUST(amount, expdest);
 589                                 return 1;
 590                         }
 591                         if ((varflags & VSQUOTE) && *loc == CTLESC)
 592                                 loc++;
 593                 }
 594                 return 0;
 595
 596
 597         default:
 598                 abort();
 599         }
 600
 601 recordleft:
 602         amount = ((str - 1) - (loc - startp)) - expdest;
 603         STADJUST(amount, expdest);
 604         while (loc != str - 1)
 605                 *startp++ = *loc++;
 606         return 1;
 607 }
 608
 609
 610 /*
 611  * Expand a variable, and return a pointer to the next character in the
 612  * input string.
 613  */
 614
 615 STATIC char *
 616 evalvar(char *p, int flag)
 617 {
 618         int subtype;
 619         int varflags;
 620         char *var;
 621         char *val;
 622         int patloc;
 623         int c;
 624         int set;
 625         int special;
 626         int startloc;
 627         int varlen;
 628         int easy;
 629         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 630
 631         varflags = (unsigned char)*p++;
 632         subtype = varflags & VSTYPE;
 633         var = p;
 634         special = 0;
 635         if (! is_name(*p))
 636                 special = 1;
 637         p = strchr(p, '=') + 1;
 638 again: /* jump here after setting a variable with ${var=text} */
 639         if (varflags & VSLINENO) {
 640                 set = 1;
 641                 special = 0;
 642                 val = var;
 643                 p[-1] = '\0';   /* temporarily overwrite '=' to have \0
 644                                    terminated string */
 645         } else if (special) {
 646                 set = varisset(var, varflags & VSNUL);
 647                 val = NULL;
 648         } else {
 649                 val = bltinlookup(var, 1);
 650                 if (val == NULL || ((varflags & VSNUL) && val[0] == '\0')) {
 651                         val = NULL;
 652                         set = 0;
 653                 } else
 654                         set = 1;
 655         }
 656         varlen = 0;
 657         startloc = expdest - stackblock();
 658         if (!set && uflag) {
 659                 switch (subtype) {
 660                 case VSNORMAL:
 661                 case VSTRIMLEFT:
 662                 case VSTRIMLEFTMAX:
 663                 case VSTRIMRIGHT:
 664                 case VSTRIMRIGHTMAX:
 665                 case VSLENGTH:
 666                         error("%.*s: parameter not set", (int)(p - var - 1),
 667                             var);
 668                 }
 669         }
 670         if (set && subtype != VSPLUS) {
 671                 /* insert the value of the variable */
 672                 if (special) {
 673                         varvalue(var, varflags & VSQUOTE, subtype, flag);
 674                         if (subtype == VSLENGTH) {
 675                                 varlen = expdest - stackblock() - startloc;
 676                                 STADJUST(-varlen, expdest);
 677                         }
 678                 } else {
 679                         char const *syntax = (varflags & VSQUOTE) ? DQSYNTAX
 680                                                                   : BASESYNTAX;
 681
 682                         if (subtype == VSLENGTH) {
 683                                 for (;*val; val++)
 684                                         varlen++;
 685                         }
 686                         else {
 687                                 while (*val) {
 688                                         if (quotes &&
 689                                             syntax[(int)*val] == CCTL)
 690                                                 STPUTC(CTLESC, expdest);
 691                                         STPUTC(*val++, expdest);
 692                                 }
 693
 694                         }
 695                 }
 696         }
 697
 698         if (subtype == VSPLUS)
 699                 set = ! set;
 700
 701         easy = ((varflags & VSQUOTE) == 0 ||
 702                 (*var == '@' && shellparam.nparam != 1));
 703
 704
 705         switch (subtype) {
 706         case VSLENGTH:
 707                 expdest = cvtnum(varlen, expdest);
 708                 goto record;
 709
 710         case VSNORMAL:
 711                 if (!easy)
 712                         break;
 713 record:
 714                 recordregion(startloc, expdest - stackblock(),
 715                              varflags & VSQUOTE);
 716                 break;
 717
 718         case VSPLUS:
 719         case VSMINUS:
 720                 if (!set) {
 721                         argstr(p, flag);
 722                         break;
 723                 }
 724                 if (easy)
 725                         goto record;
 726                 break;
 727
 728         case VSTRIMLEFT:
 729         case VSTRIMLEFTMAX:
 730         case VSTRIMRIGHT:
 731         case VSTRIMRIGHTMAX:
 732                 if (!set)
 733                         break;
 734                 /*
 735                  * Terminate the string and start recording the pattern
 736                  * right after it
 737                  */
 738                 STPUTC('\0', expdest);
 739                 patloc = expdest - stackblock();
 740                 if (subevalvar(p, NULL, patloc, subtype,
 741                                startloc, varflags) == 0) {
 742                         int amount = (expdest - stackblock() - patloc) + 1;
 743                         STADJUST(-amount, expdest);
 744                 }
 745                 /* Remove any recorded regions beyond start of variable */
 746                 removerecordregions(startloc);
 747                 goto record;
 748
 749         case VSASSIGN:
 750         case VSQUESTION:
 751                 if (!set) {
 752                         if (subevalvar(p, var, 0, subtype, startloc, varflags)) {
 753                                 varflags &= ~VSNUL;
 754                                 /*
 755                                  * Remove any recorded regions beyond
 756                                  * start of variable
 757                                  */
 758                                 removerecordregions(startloc);
 759                                 goto again;
 760                         }
 761                         break;
 762                 }
 763                 if (easy)
 764                         goto record;
 765                 break;
 766
 767         case VSERROR:
 768                 c = p - var - 1;
 769                 error("${%.*s%s}: Bad substitution", c, var,
 770                     (c > 0 && *p != CTLENDVAR) ? "..." : "");
 771
 772         default:
 773                 abort();
 774         }
 775         p[-1] = '=';    /* recover overwritten '=' */
 776
 777         if (subtype != VSNORMAL) {      /* skip to end of alternative */
 778                 int nesting = 1;
 779                 for (;;) {
 780                         if ((c = *p++) == CTLESC)
 781                                 p++;
 782                         else if (c == CTLBACKQ || c == (CTLBACKQ|CTLQUOTE)) {
 783                                 if (set)
 784                                         argbackq = argbackq->next;
 785                         } else if (c == CTLVAR) {
 786                                 if ((*p++ & VSTYPE) != VSNORMAL)
 787                                         nesting++;
 788                         } else if (c == CTLENDVAR) {
 789                                 if (--nesting == 0)
 790                                         break;
 791                         }
 792                 }
 793         }
 794         return p;
 795 }
 796
 797
 798
 799 /*
 800  * Test whether a specialized variable is set.
 801  */
 802
 803 STATIC int
 804 varisset(char *name, int nulok)
 805 {
 806
 807         if (*name == '!')
 808                 return backgndpid != -1;
 809         else if (*name == '@' || *name == '*') {
 810                 if (*shellparam.p == NULL)
 811                         return 0;
 812
 813                 if (nulok) {
 814                         char **av;
 815
 816                         for (av = shellparam.p; *av; av++)
 817                                 if (**av != '\0')
 818                                         return 1;
 819                         return 0;
 820                 }
 821         } else if (is_digit(*name)) {
 822                 char *ap;
 823                 int num = atoi(name);
 824
 825                 if (num > shellparam.nparam)
 826                         return 0;
 827
 828                 if (num == 0)
 829                         ap = arg0;
 830                 else
 831                         ap = shellparam.p[num - 1];
 832
 833                 if (nulok && (ap == NULL || *ap == '\0'))
 834                         return 0;
 835         }
 836         return 1;
 837 }
 838
 839
 840
 841 /*
 842  * Add the value of a specialized variable to the stack string.
 843  */
 844
 845 STATIC void
 846 varvalue(char *name, int quoted, int subtype, int flag)
 847 {
 848         int num;
 849         char *p;
 850         int i;
 851         char sep;
 852         char **ap;
 853         char const *syntax;
 854
 855 #define STRTODEST(p) \
 856         do {\
 857         if (flag & (EXP_FULL | EXP_CASE) && subtype != VSLENGTH) { \
 858                 syntax = quoted? DQSYNTAX : BASESYNTAX; \
 859                 while (*p) { \
 860                         if (syntax[(int)*p] == CCTL) \
 861                                 STPUTC(CTLESC, expdest); \
 862                         STPUTC(*p++, expdest); \
 863                 } \
 864         } else \
 865                 while (*p) \
 866                         STPUTC(*p++, expdest); \
 867         } while (0)
 868
 869
 870         switch (*name) {
 871         case '$':
 872                 num = rootpid;
 873                 goto numvar;
 874         case '?':
 875                 num = oexitstatus;
 876                 goto numvar;
 877         case '#':
 878                 num = shellparam.nparam;
 879                 goto numvar;
 880         case '!':
 881                 num = backgndpid;
 882 numvar:
 883                 expdest = cvtnum(num, expdest);
 884                 break;
 885         case '-':
 886                 for (i = 0 ; i < NOPTS ; i++) {
 887                         if (optlist[i].val)
 888                                 STPUTC(optlist[i].letter, expdest);
 889                 }
 890                 break;
 891         case '@':
 892                 if (flag & EXP_FULL && quoted) {
 893                         for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
 894                                 STRTODEST(p);
 895                                 if (*ap)
 896                                         STPUTC('\0', expdest);
 897                         }
 898                         break;
 899                 }
 900                 /* FALLTHROUGH */
 901         case '*':
 902                 if (ifsset())
 903                         sep = ifsval()[0];
 904                 else
 905                         sep = ' ';
 906                 for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
 907                         STRTODEST(p);
 908                         if (*ap && sep)
 909                                 STPUTC(sep, expdest);
 910                 }
 911                 break;
 912         case '0':
 913                 p = arg0;
 914                 STRTODEST(p);
 915                 break;
 916         default:
 917                 if (is_digit(*name)) {
 918                         num = atoi(name);
 919                         if (num > 0 && num <= shellparam.nparam) {
 920                                 p = shellparam.p[num - 1];
 921                                 STRTODEST(p);
 922                         }
 923                 }
 924                 break;
 925         }
 926 }
 927
 928
 929
 930 /*
 931  * Record the the fact that we have to scan this region of the
 932  * string for IFS characters.
 933  */
 934
 935 STATIC void
 936 recordregion(int start, int end, int nulonly)
 937 {
 938         struct ifsregion *ifsp;
 939
 940         if (ifslastp == NULL) {
 941                 ifsp = &ifsfirst;
 942         } else {
 943                 ifsp = (struct ifsregion *)ckmalloc(sizeof (struct ifsregion));
 944                 ifslastp->next = ifsp;
 945         }
 946         ifslastp = ifsp;
 947         ifslastp->next = NULL;
 948         ifslastp->begoff = start;
 949         ifslastp->endoff = end;
 950         ifslastp->nulonly = nulonly;
 951 }
 952
 953
 954
 955 /*
 956  * Break the argument string into pieces based upon IFS and add the
 957  * strings to the argument list.  The regions of the string to be
 958  * searched for IFS characters have been stored by recordregion.
 959  */
 960 STATIC void
 961 ifsbreakup(char *string, struct arglist *arglist)
 962 {
 963         struct ifsregion *ifsp;
 964         struct strlist *sp;
 965         char *start;
 966         char *p;
 967         char *q;
 968         const char *ifs;
 969         int ifsspc;
 970         int nulonly;
 971
 972
 973         start = string;
 974         ifsspc = 0;
 975         nulonly = 0;
 976         if (ifslastp != NULL) {
 977                 ifsp = &ifsfirst;
 978                 do {
 979                         p = string + ifsp->begoff;
 980                         nulonly = ifsp->nulonly;
 981                         ifs = nulonly ? nullstr :
 982                                 ( ifsset() ? ifsval() : " \t\n" );
 983                         ifsspc = 0;
 984                         while (p < string + ifsp->endoff) {
 985                                 q = p;
 986                                 if (*p == CTLESC)
 987                                         p++;
 988                                 if (strchr(ifs, *p)) {
 989                                         if (!nulonly)
 990                                                 ifsspc = (strchr(" \t\n", *p) != NULL);
 991                                         /* Ignore IFS whitespace at start */
 992                                         if (q == start && ifsspc) {
 993                                                 p++;
 994                                                 start = p;
 995                                                 continue;
 996                                         }
 997                                         *q = '\0';
 998                                         sp = (struct strlist *)stalloc(sizeof *sp);
 999                                         sp->text = start;
1000                                         *arglist->lastp = sp;
1001                                         arglist->lastp = &sp->next;
1002                                         p++;
1003                                         if (!nulonly) {
1004                                                 for (;;) {
1005                                                         if (p >= string + ifsp->endoff) {
1006                                                                 break;
1007                                                         }
1008                                                         q = p;
1009                                                         if (*p == CTLESC)
1010                                                                 p++;
1011                                                         if (strchr(ifs, *p) == NULL ) {
1012                                                                 p = q;
1013                                                                 break;
1014                                                         } else if (strchr(" \t\n",*p) == NULL) {
1015                                                                 if (ifsspc) {
1016                                                                         p++;
1017                                                                         ifsspc = 0;
1018                                                                 } else {
1019                                                                         p = q;
1020                                                                         break;
1021                                                                 }
1022                                                         } else
1023                                                                 p++;
1024                                                 }
1025                                         }
1026                                         start = p;
1027                                 } else
1028                                         p++;
1029                         }
1030                 } while ((ifsp = ifsp->next) != NULL);
1031                 if (*start || (!ifsspc && start > string)) {
1032                         sp = (struct strlist *)stalloc(sizeof *sp);
1033                         sp->text = start;
1034                         *arglist->lastp = sp;
1035                         arglist->lastp = &sp->next;
1036                 }
1037         } else {
1038                 sp = (struct strlist *)stalloc(sizeof *sp);
1039                 sp->text = start;
1040                 *arglist->lastp = sp;
1041                 arglist->lastp = &sp->next;
1042         }
1043 }
1044
1045
1046
1047 /*
1048  * Expand shell metacharacters.  At this point, the only control characters
1049  * should be escapes.  The results are stored in the list exparg.
1050  */
1051
1052 STATIC char *expdir;
1053
1054
1055 STATIC void
1056 expandmeta(struct strlist *str, int flag __unused)
1057 {
1058         char *p;
1059         struct strlist **savelastp;
1060         struct strlist *sp;
1061         char c;
1062         /* TODO - EXP_REDIR */
1063
1064         while (str) {
1065                 if (fflag)
1066                         goto nometa;
1067                 p = str->text;
1068                 for (;;) {                      /* fast check for meta chars */
1069                         if ((c = *p++) == '\0')
1070                                 goto nometa;
1071                         if (c == '*' || c == '?' || c == '[' || c == '!')
1072                                 break;
1073                 }
1074                 savelastp = exparg.lastp;
1075                 INTOFF;
1076                 if (expdir == NULL) {
1077                         int i = strlen(str->text);
1078                         expdir = ckmalloc(i < 2048 ? 2048 : i); /* XXX */
1079                 }
1080
1081                 expmeta(expdir, str->text);
1082                 ckfree(expdir);
1083                 expdir = NULL;
1084                 INTON;
1085                 if (exparg.lastp == savelastp) {
1086                         /*
1087                          * no matches
1088                          */
1089 nometa:
1090                         *exparg.lastp = str;
1091                         rmescapes(str->text);
1092                         exparg.lastp = &str->next;
1093                 } else {
1094                         *exparg.lastp = NULL;
1095                         *savelastp = sp = expsort(*savelastp);
1096                         while (sp->next != NULL)
1097                                 sp = sp->next;
1098                         exparg.lastp = &sp->next;
1099                 }
1100                 str = str->next;
1101         }
1102 }
1103
1104
1105 /*
1106  * Do metacharacter (i.e. *, ?, [...]) expansion.
1107  */
1108
1109 STATIC void
1110 expmeta(char *enddir, char *name)
1111 {
1112         char *p;
1113         const char *q;
1114         char *start;
1115         char *endname;
1116         int metaflag;
1117         struct stat statb;
1118         DIR *dirp;
1119         struct dirent *dp;
1120         int atend;
1121         int matchdot;
1122
1123         metaflag = 0;
1124         start = name;
1125         for (p = name ; ; p++) {
1126                 if (*p == '*' || *p == '?')
1127                         metaflag = 1;
1128                 else if (*p == '[') {
1129                         q = p + 1;
1130                         if (*q == '!' || *q == '^')
1131                                 q++;
1132                         for (;;) {
1133                                 while (*q == CTLQUOTEMARK)
1134                                         q++;
1135                                 if (*q == CTLESC)
1136                                         q++;
1137                                 if (*q == '/' || *q == '\0')
1138                                         break;
1139                                 if (*++q == ']') {
1140                                         metaflag = 1;
1141                                         break;
1142                                 }
1143                         }
1144                 } else if (*p == '!' && p[1] == '!'     && (p == name || p[-1] == '/')) {
1145                         metaflag = 1;
1146                 } else if (*p == '\0')
1147                         break;
1148                 else if (*p == CTLQUOTEMARK)
1149                         continue;
1150                 else if (*p == CTLESC)
1151                         p++;
1152                 if (*p == '/') {
1153                         if (metaflag)
1154                                 break;
1155                         start = p + 1;
1156                 }
1157         }
1158         if (metaflag == 0) {    /* we've reached the end of the file name */
1159                 if (enddir != expdir)
1160                         metaflag++;
1161                 for (p = name ; ; p++) {
1162                         if (*p == CTLQUOTEMARK)
1163                                 continue;
1164                         if (*p == CTLESC)
1165                                 p++;
1166                         *enddir++ = *p;
1167                         if (*p == '\0')
1168                                 break;
1169                 }
1170                 if (metaflag == 0 || lstat(expdir, &statb) >= 0)
1171                         addfname(expdir);
1172                 return;
1173         }
1174         endname = p;
1175         if (start != name) {
1176                 p = name;
1177                 while (p < start) {
1178                         while (*p == CTLQUOTEMARK)
1179                                 p++;
1180                         if (*p == CTLESC)
1181                                 p++;
1182                         *enddir++ = *p++;
1183                 }
1184         }
1185         if (enddir == expdir) {
1186                 q = ".";
1187         } else if (enddir == expdir + 1 && *expdir == '/') {
1188                 q = "/";
1189         } else {
1190                 q = expdir;
1191                 enddir[-1] = '\0';
1192         }
1193         if ((dirp = opendir(q)) == NULL)
1194                 return;
1195         if (enddir != expdir)
1196                 enddir[-1] = '/';
1197         if (*endname == 0) {
1198                 atend = 1;
1199         } else {
1200                 atend = 0;
1201                 *endname++ = '\0';
1202         }
1203         matchdot = 0;
1204         p = start;
1205         while (*p == CTLQUOTEMARK)
1206                 p++;
1207         if (*p == CTLESC)
1208                 p++;
1209         if (*p == '.')
1210                 matchdot++;
1211         while (! int_pending() && (dp = readdir(dirp)) != NULL) {
1212                 if (dp->d_name[0] == '.' && ! matchdot)
1213                         continue;
1214                 if (patmatch(start, dp->d_name, 0)) {
1215                         if (atend) {
1216                                 scopy(dp->d_name, enddir);
1217                                 addfname(expdir);
1218                         } else {
1219                                 char *t;
1220                                 for (t = enddir, q = dp->d_name;
1221                                      (*t++ = *q++) != '\0';)
1222                                         continue;
1223                                 t[-1] = '/';
1224                                 expmeta(t, endname);
1225                         }
1226                 }
1227         }
1228         closedir(dirp);
1229         if (! atend)
1230                 endname[-1] = '/';
1231 }
1232
1233
1234 /*
1235  * Add a file name to the list.
1236  */
1237
1238 STATIC void
1239 addfname(char *name)
1240 {
1241         char *p;
1242         struct strlist *sp;
1243
1244         p = stalloc(strlen(name) + 1);
1245         scopy(name, p);
1246         sp = (struct strlist *)stalloc(sizeof *sp);
1247         sp->text = p;
1248         *exparg.lastp = sp;
1249         exparg.lastp = &sp->next;
1250 }
1251
1252
1253 /*
1254  * Sort the results of file name expansion.  It calculates the number of
1255  * strings to sort and then calls msort (short for merge sort) to do the
1256  * work.
1257  */
1258
1259 STATIC struct strlist *
1260 expsort(struct strlist *str)
1261 {
1262         int len;
1263         struct strlist *sp;
1264
1265         len = 0;
1266         for (sp = str ; sp ; sp = sp->next)
1267                 len++;
1268         return msort(str, len);
1269 }
1270
1271
1272 STATIC struct strlist *
1273 msort(struct strlist *list, int len)
1274 {
1275         struct strlist *p, *q = NULL;
1276         struct strlist **lpp;
1277         int half;
1278         int n;
1279
1280         if (len <= 1)
1281                 return list;
1282         half = len >> 1;
1283         p = list;
1284         for (n = half ; --n >= 0 ; ) {
1285                 q = p;
1286                 p = p->next;
1287         }
1288         q->next = NULL;                 /* terminate first half of list */
1289         q = msort(list, half);          /* sort first half of list */
1290         p = msort(p, len - half);               /* sort second half */
1291         lpp = &list;
1292         for (;;) {
1293                 if (strcmp(p->text, q->text) < 0) {
1294                         *lpp = p;
1295                         lpp = &p->next;
1296                         if ((p = *lpp) == NULL) {
1297                                 *lpp = q;
1298                                 break;
1299                         }
1300                 } else {
1301                         *lpp = q;
1302                         lpp = &q->next;
1303                         if ((q = *lpp) == NULL) {
1304                                 *lpp = p;
1305                                 break;
1306                         }
1307                 }
1308         }
1309         return list;
1310 }
1311
1312
1313
1314 /*
1315  * Returns true if the pattern matches the string.
1316  */
1317
1318 int
1319 patmatch(char *pattern, char *string, int squoted)
1320 {
1321 #ifdef notdef
1322         if (pattern[0] == '!' && pattern[1] == '!')
1323                 return 1 - pmatch(pattern + 2, string);
1324         else
1325 #endif
1326                 return pmatch(pattern, string, squoted);
1327 }
1328
1329
1330 STATIC int
1331 pmatch(char *pattern, char *string, int squoted)
1332 {
1333         char *p, *q;
1334         char c;
1335
1336         p = pattern;
1337         q = string;
1338         for (;;) {
1339                 switch (c = *p++) {
1340                 case '\0':
1341                         goto breakloop;
1342                 case CTLESC:
1343                         if (squoted && *q == CTLESC)
1344                                 q++;
1345                         if (*q++ != *p++)
1346                                 return 0;
1347                         break;
1348                 case CTLQUOTEMARK:
1349                         continue;
1350                 case '?':
1351                         if (squoted && *q == CTLESC)
1352                                 q++;
1353                         if (*q++ == '\0')
1354                                 return 0;
1355                         break;
1356                 case '*':
1357                         c = *p;
1358                         while (c == CTLQUOTEMARK || c == '*')
1359                                 c = *++p;
1360                         if (c != CTLESC &&  c != CTLQUOTEMARK &&
1361                             c != '?' && c != '*' && c != '[') {
1362                                 while (*q != c) {
1363                                         if (squoted && *q == CTLESC &&
1364                                             q[1] == c)
1365                                                 break;
1366                                         if (*q == '\0')
1367                                                 return 0;
1368                                         if (squoted && *q == CTLESC)
1369                                                 q++;
1370                                         q++;
1371                                 }
1372                         }
1373                         do {
1374                                 if (pmatch(p, q, squoted))
1375                                         return 1;
1376                                 if (squoted && *q == CTLESC)
1377                                         q++;
1378                         } while (*q++ != '\0');
1379                         return 0;
1380                 case '[': {
1381                         char *endp;
1382                         int invert, found;
1383                         char chr;
1384
1385                         endp = p;
1386                         if (*endp == '!' || *endp == '^')
1387                                 endp++;
1388                         for (;;) {
1389                                 while (*endp == CTLQUOTEMARK)
1390                                         endp++;
1391                                 if (*endp == '\0')
1392                                         goto dft;               /* no matching ] */
1393                                 if (*endp == CTLESC)
1394                                         endp++;
1395                                 if (*++endp == ']')
1396                                         break;
1397                         }
1398                         invert = 0;
1399                         if (*p == '!' || *p == '^') {
1400                                 invert++;
1401                                 p++;
1402                         }
1403                         found = 0;
1404                         chr = *q++;
1405                         if (squoted && chr == CTLESC)
1406                                 chr = *q++;
1407                         if (chr == '\0')
1408                                 return 0;
1409                         c = *p++;
1410                         do {
1411                                 if (c == CTLQUOTEMARK)
1412                                         continue;
1413                                 if (c == CTLESC)
1414                                         c = *p++;
1415                                 if (*p == '-' && p[1] != ']') {
1416                                         p++;
1417                                         while (*p == CTLQUOTEMARK)
1418                                                 p++;
1419                                         if (*p == CTLESC)
1420                                                 p++;
1421                                         if (   collate_range_cmp(chr, c) >= 0
1422                                             && collate_range_cmp(chr, *p) <= 0
1423                                            )
1424                                                 found = 1;
1425                                         p++;
1426                                 } else {
1427                                         if (chr == c)
1428                                                 found = 1;
1429                                 }
1430                         } while ((c = *p++) != ']');
1431                         if (found == invert)
1432                                 return 0;
1433                         break;
1434                 }
1435 dft:            default:
1436                         if (squoted && *q == CTLESC)
1437                                 q++;
1438                         if (*q++ != c)
1439                                 return 0;
1440                         break;
1441                 }
1442         }
1443 breakloop:
1444         if (*q != '\0')
1445                 return 0;
1446         return 1;
1447 }
1448
1449
1450
1451 /*
1452  * Remove any CTLESC characters from a string.
1453  */
1454
1455 void
1456 rmescapes(char *str)
1457 {
1458         char *p, *q;
1459
1460         p = str;
1461         while (*p != CTLESC && *p != CTLQUOTEMARK) {
1462                 if (*p++ == '\0')
1463                         return;
1464         }
1465         q = p;
1466         while (*p) {
1467                 if (*p == CTLQUOTEMARK) {
1468                         p++;
1469                         continue;
1470                 }
1471                 if (*p == CTLESC)
1472                         p++;
1473                 *q++ = *p++;
1474         }
1475         *q = '\0';
1476 }
1477
1478
1479
1480 /*
1481  * See if a pattern matches in a case statement.
1482  */
1483
1484 int
1485 casematch(union node *pattern, char *val)
1486 {
1487         struct stackmark smark;
1488         int result;
1489         char *p;
1490
1491         setstackmark(&smark);
1492         argbackq = pattern->narg.backquote;
1493         STARTSTACKSTR(expdest);
1494         ifslastp = NULL;
1495         argstr(pattern->narg.text, EXP_TILDE | EXP_CASE);
1496         STPUTC('\0', expdest);
1497         p = grabstackstr(expdest);
1498         result = patmatch(p, val, 0);
1499         popstackmark(&smark);
1500         return result;
1501 }
1502
1503 /*
1504  * Our own itoa().
1505  */
1506
1507 STATIC char *
1508 cvtnum(int num, char *buf)
1509 {
1510         char temp[32];
1511         int neg = num < 0;
1512         char *p = temp + 31;
1513
1514         temp[31] = '\0';
1515
1516         do {
1517                 *--p = num % 10 + '0';
1518         } while ((num /= 10) != 0);
1519
1520         if (neg)
1521                 *--p = '-';
1522
1523         while (*p)
1524                 STPUTC(*p++, buf);
1525         return buf;
1526 }
1527
1528 /*
1529  * Do most of the work for wordexp(3).
1530  */
1531
1532 int
1533 wordexpcmd(int argc, char **argv)
1534 {
1535         size_t len;
1536         int i;
1537
1538         out1fmt("%08x", argc - 1);
1539         for (i = 1, len = 0; i < argc; i++)
1540                 len += strlen(argv[i]);
1541         out1fmt("%08x", (int)len);
1542         for (i = 1; i < argc; i++) {
1543                 out1str(argv[i]);
1544                 out1c('\0');
1545         }
1546         return (0);
1547 }