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, (struct arglist *)NULL, 0);
 137         xwrite(fd, stackblock(), expdest - stackblock());
 138 }
 139
 140
 141 /*
 142  * Perform variable substitution and command substitution on an argument,
 143  * placing the resulting list of arguments in arglist.  If EXP_FULL is true,
 144  * perform splitting and file name expansion.  When arglist is NULL, perform
 145  * here document expansion.
 146  */
 147
 148 void
 149 expandarg(union node *arg, struct arglist *arglist, int flag)
 150 {
 151         struct strlist *sp;
 152         char *p;
 153
 154         argbackq = arg->narg.backquote;
 155         STARTSTACKSTR(expdest);
 156         ifsfirst.next = NULL;
 157         ifslastp = NULL;
 158         argstr(arg->narg.text, flag);
 159         if (arglist == NULL) {
 160                 return;                 /* here document expanded */
 161         }
 162         STPUTC('\0', expdest);
 163         p = grabstackstr(expdest);
 164         exparg.lastp = &exparg.list;
 165         /*
 166          * TODO - EXP_REDIR
 167          */
 168         if (flag & EXP_FULL) {
 169                 ifsbreakup(p, &exparg);
 170                 *exparg.lastp = NULL;
 171                 exparg.lastp = &exparg.list;
 172                 expandmeta(exparg.list, flag);
 173         } else {
 174                 if (flag & EXP_REDIR) /*XXX - for now, just remove escapes */
 175                         rmescapes(p);
 176                 sp = (struct strlist *)stalloc(sizeof (struct strlist));
 177                 sp->text = p;
 178                 *exparg.lastp = sp;
 179                 exparg.lastp = &sp->next;
 180         }
 181         while (ifsfirst.next != NULL) {
 182                 struct ifsregion *ifsp;
 183                 INTOFF;
 184                 ifsp = ifsfirst.next->next;
 185                 ckfree(ifsfirst.next);
 186                 ifsfirst.next = ifsp;
 187                 INTON;
 188         }
 189         *exparg.lastp = NULL;
 190         if (exparg.list) {
 191                 *arglist->lastp = exparg.list;
 192                 arglist->lastp = exparg.lastp;
 193         }
 194 }
 195
 196
 197
 198 /*
 199  * Perform variable and command substitution.  If EXP_FULL is set, output CTLESC
 200  * characters to allow for further processing.  Otherwise treat
 201  * $@ like $* since no splitting will be performed.
 202  */
 203
 204 STATIC void
 205 argstr(char *p, int flag)
 206 {
 207         char c;
 208         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);  /* do CTLESC */
 209         int firsteq = 1;
 210
 211         if (*p == '~' && (flag & (EXP_TILDE | EXP_VARTILDE)))
 212                 p = exptilde(p, flag);
 213         for (;;) {
 214                 switch (c = *p++) {
 215                 case '\0':
 216                 case CTLENDVAR: /* ??? */
 217                         goto breakloop;
 218                 case CTLQUOTEMARK:
 219                         /* "$@" syntax adherence hack */
 220                         if (p[0] == CTLVAR && p[2] == '@' && p[3] == '=')
 221                                 break;
 222                         if ((flag & EXP_FULL) != 0)
 223                                 STPUTC(c, expdest);
 224                         break;
 225                 case CTLESC:
 226                         if (quotes)
 227                                 STPUTC(c, expdest);
 228                         c = *p++;
 229                         STPUTC(c, expdest);
 230                         break;
 231                 case CTLVAR:
 232                         p = evalvar(p, flag);
 233                         break;
 234                 case CTLBACKQ:
 235                 case CTLBACKQ|CTLQUOTE:
 236                         expbackq(argbackq->n, c & CTLQUOTE, flag);
 237                         argbackq = argbackq->next;
 238                         break;
 239                 case CTLENDARI:
 240                         expari(flag);
 241                         break;
 242                 case ':':
 243                 case '=':
 244                         /*
 245                          * sort of a hack - expand tildes in variable
 246                          * assignments (after the first '=' and after ':'s).
 247                          */
 248                         STPUTC(c, expdest);
 249                         if (flag & EXP_VARTILDE && *p == '~') {
 250                                 if (c == '=') {
 251                                         if (firsteq)
 252                                                 firsteq = 0;
 253                                         else
 254                                                 break;
 255                                 }
 256                                 p = exptilde(p, flag);
 257                         }
 258                         break;
 259                 default:
 260                         STPUTC(c, expdest);
 261                 }
 262         }
 263 breakloop:;
 264 }
 265
 266 STATIC char *
 267 exptilde(char *p, int flag)
 268 {
 269         char c, *startp = p;
 270         struct passwd *pw;
 271         char *home;
 272         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 273
 274         while ((c = *p) != '\0') {
 275                 switch(c) {
 276                 case CTLESC:
 277                         return (startp);
 278                 case CTLQUOTEMARK:
 279                         return (startp);
 280                 case ':':
 281                         if (flag & EXP_VARTILDE)
 282                                 goto done;
 283                         break;
 284                 case '/':
 285                         goto done;
 286                 }
 287                 p++;
 288         }
 289 done:
 290         *p = '\0';
 291         if (*(startp+1) == '\0') {
 292                 if ((home = lookupvar("HOME")) == NULL)
 293                         goto lose;
 294         } else {
 295                 if ((pw = getpwnam(startp+1)) == NULL)
 296                         goto lose;
 297                 home = pw->pw_dir;
 298         }
 299         if (*home == '\0')
 300                 goto lose;
 301         *p = c;
 302         while ((c = *home++) != '\0') {
 303                 if (quotes && SQSYNTAX[(int)c] == CCTL)
 304                         STPUTC(CTLESC, expdest);
 305                 STPUTC(c, expdest);
 306         }
 307         return (p);
 308 lose:
 309         *p = c;
 310         return (startp);
 311 }
 312
 313
 314 STATIC void
 315 removerecordregions(int endoff)
 316 {
 317         if (ifslastp == NULL)
 318                 return;
 319
 320         if (ifsfirst.endoff > endoff) {
 321                 while (ifsfirst.next != NULL) {
 322                         struct ifsregion *ifsp;
 323                         INTOFF;
 324                         ifsp = ifsfirst.next->next;
 325                         ckfree(ifsfirst.next);
 326                         ifsfirst.next = ifsp;
 327                         INTON;
 328                 }
 329                 if (ifsfirst.begoff > endoff)
 330                         ifslastp = NULL;
 331                 else {
 332                         ifslastp = &ifsfirst;
 333                         ifsfirst.endoff = endoff;
 334                 }
 335                 return;
 336         }
 337
 338         ifslastp = &ifsfirst;
 339         while (ifslastp->next && ifslastp->next->begoff < endoff)
 340                 ifslastp=ifslastp->next;
 341         while (ifslastp->next != NULL) {
 342                 struct ifsregion *ifsp;
 343                 INTOFF;
 344                 ifsp = ifslastp->next->next;
 345                 ckfree(ifslastp->next);
 346                 ifslastp->next = ifsp;
 347                 INTON;
 348         }
 349         if (ifslastp->endoff > endoff)
 350                 ifslastp->endoff = endoff;
 351 }
 352
 353 /*
 354  * Expand arithmetic expression.  Backup to start of expression,
 355  * evaluate, place result in (backed up) result, adjust string position.
 356  */
 357 void
 358 expari(int flag)
 359 {
 360         char *p, *start;
 361         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, (int *)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((char *)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 (special) {
 640                 set = varisset(var, varflags & VSNUL);
 641                 val = NULL;
 642         } else {
 643                 val = bltinlookup(var, 1);
 644                 if (val == NULL || ((varflags & VSNUL) && val[0] == '\0')) {
 645                         val = NULL;
 646                         set = 0;
 647                 } else
 648                         set = 1;
 649         }
 650         varlen = 0;
 651         startloc = expdest - stackblock();
 652         if (!set && uflag) {
 653                 switch (subtype) {
 654                 case VSNORMAL:
 655                 case VSTRIMLEFT:
 656                 case VSTRIMLEFTMAX:
 657                 case VSTRIMRIGHT:
 658                 case VSTRIMRIGHTMAX:
 659                 case VSLENGTH:
 660                         error("%.*s: parameter not set", (int)(p - var - 1),
 661                             var);
 662                 }
 663         }
 664         if (set && subtype != VSPLUS) {
 665                 /* insert the value of the variable */
 666                 if (special) {
 667                         varvalue(var, varflags & VSQUOTE, subtype, flag);
 668                         if (subtype == VSLENGTH) {
 669                                 varlen = expdest - stackblock() - startloc;
 670                                 STADJUST(-varlen, expdest);
 671                         }
 672                 } else {
 673                         char const *syntax = (varflags & VSQUOTE) ? DQSYNTAX
 674                                                                   : BASESYNTAX;
 675
 676                         if (subtype == VSLENGTH) {
 677                                 for (;*val; val++)
 678                                         varlen++;
 679                         }
 680                         else {
 681                                 while (*val) {
 682                                         if (quotes &&
 683                                             syntax[(int)*val] == CCTL)
 684                                                 STPUTC(CTLESC, expdest);
 685                                         STPUTC(*val++, expdest);
 686                                 }
 687
 688                         }
 689                 }
 690         }
 691
 692         if (subtype == VSPLUS)
 693                 set = ! set;
 694
 695         easy = ((varflags & VSQUOTE) == 0 ||
 696                 (*var == '@' && shellparam.nparam != 1));
 697
 698
 699         switch (subtype) {
 700         case VSLENGTH:
 701                 expdest = cvtnum(varlen, expdest);
 702                 goto record;
 703
 704         case VSNORMAL:
 705                 if (!easy)
 706                         break;
 707 record:
 708                 recordregion(startloc, expdest - stackblock(),
 709                              varflags & VSQUOTE);
 710                 break;
 711
 712         case VSPLUS:
 713         case VSMINUS:
 714                 if (!set) {
 715                         argstr(p, flag);
 716                         break;
 717                 }
 718                 if (easy)
 719                         goto record;
 720                 break;
 721
 722         case VSTRIMLEFT:
 723         case VSTRIMLEFTMAX:
 724         case VSTRIMRIGHT:
 725         case VSTRIMRIGHTMAX:
 726                 if (!set)
 727                         break;
 728                 /*
 729                  * Terminate the string and start recording the pattern
 730                  * right after it
 731                  */
 732                 STPUTC('\0', expdest);
 733                 patloc = expdest - stackblock();
 734                 if (subevalvar(p, NULL, patloc, subtype,
 735                                startloc, varflags) == 0) {
 736                         int amount = (expdest - stackblock() - patloc) + 1;
 737                         STADJUST(-amount, expdest);
 738                 }
 739                 /* Remove any recorded regions beyond start of variable */
 740                 removerecordregions(startloc);
 741                 goto record;
 742
 743         case VSASSIGN:
 744         case VSQUESTION:
 745                 if (!set) {
 746                         if (subevalvar(p, var, 0, subtype, startloc, varflags)) {
 747                                 varflags &= ~VSNUL;
 748                                 /*
 749                                  * Remove any recorded regions beyond
 750                                  * start of variable
 751                                  */
 752                                 removerecordregions(startloc);
 753                                 goto again;
 754                         }
 755                         break;
 756                 }
 757                 if (easy)
 758                         goto record;
 759                 break;
 760
 761         case VSERROR:
 762                 c = p - var - 1;
 763                 error("${%.*s%s}: Bad substitution", c, var,
 764                     (c > 0 && *p != CTLENDVAR) ? "..." : "");
 765
 766         default:
 767                 abort();
 768         }
 769
 770         if (subtype != VSNORMAL) {      /* skip to end of alternative */
 771                 int nesting = 1;
 772                 for (;;) {
 773                         if ((c = *p++) == CTLESC)
 774                                 p++;
 775                         else if (c == CTLBACKQ || c == (CTLBACKQ|CTLQUOTE)) {
 776                                 if (set)
 777                                         argbackq = argbackq->next;
 778                         } else if (c == CTLVAR) {
 779                                 if ((*p++ & VSTYPE) != VSNORMAL)
 780                                         nesting++;
 781                         } else if (c == CTLENDVAR) {
 782                                 if (--nesting == 0)
 783                                         break;
 784                         }
 785                 }
 786         }
 787         return p;
 788 }
 789
 790
 791
 792 /*
 793  * Test whether a specialized variable is set.
 794  */
 795
 796 STATIC int
 797 varisset(char *name, int nulok)
 798 {
 799
 800         if (*name == '!')
 801                 return backgndpid != -1;
 802         else if (*name == '@' || *name == '*') {
 803                 if (*shellparam.p == NULL)
 804                         return 0;
 805
 806                 if (nulok) {
 807                         char **av;
 808
 809                         for (av = shellparam.p; *av; av++)
 810                                 if (**av != '\0')
 811                                         return 1;
 812                         return 0;
 813                 }
 814         } else if (is_digit(*name)) {
 815                 char *ap;
 816                 int num = atoi(name);
 817
 818                 if (num > shellparam.nparam)
 819                         return 0;
 820
 821                 if (num == 0)
 822                         ap = arg0;
 823                 else
 824                         ap = shellparam.p[num - 1];
 825
 826                 if (nulok && (ap == NULL || *ap == '\0'))
 827                         return 0;
 828         }
 829         return 1;
 830 }
 831
 832
 833
 834 /*
 835  * Add the value of a specialized variable to the stack string.
 836  */
 837
 838 STATIC void
 839 varvalue(char *name, int quoted, int subtype, int flag)
 840 {
 841         int num;
 842         char *p;
 843         int i;
 844         char sep;
 845         char **ap;
 846         char const *syntax;
 847
 848 #define STRTODEST(p) \
 849         do {\
 850         if (flag & (EXP_FULL | EXP_CASE) && subtype != VSLENGTH) { \
 851                 syntax = quoted? DQSYNTAX : BASESYNTAX; \
 852                 while (*p) { \
 853                         if (syntax[(int)*p] == CCTL) \
 854                                 STPUTC(CTLESC, expdest); \
 855                         STPUTC(*p++, expdest); \
 856                 } \
 857         } else \
 858                 while (*p) \
 859                         STPUTC(*p++, expdest); \
 860         } while (0)
 861
 862
 863         switch (*name) {
 864         case '$':
 865                 num = rootpid;
 866                 goto numvar;
 867         case '?':
 868                 num = oexitstatus;
 869                 goto numvar;
 870         case '#':
 871                 num = shellparam.nparam;
 872                 goto numvar;
 873         case '!':
 874                 num = backgndpid;
 875 numvar:
 876                 expdest = cvtnum(num, expdest);
 877                 break;
 878         case '-':
 879                 for (i = 0 ; i < NOPTS ; i++) {
 880                         if (optlist[i].val)
 881                                 STPUTC(optlist[i].letter, expdest);
 882                 }
 883                 break;
 884         case '@':
 885                 if (flag & EXP_FULL && quoted) {
 886                         for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
 887                                 STRTODEST(p);
 888                                 if (*ap)
 889                                         STPUTC('\0', expdest);
 890                         }
 891                         break;
 892                 }
 893                 /* FALLTHROUGH */
 894         case '*':
 895                 if (ifsset())
 896                         sep = ifsval()[0];
 897                 else
 898                         sep = ' ';
 899                 for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
 900                         STRTODEST(p);
 901                         if (*ap && sep)
 902                                 STPUTC(sep, expdest);
 903                 }
 904                 break;
 905         case '0':
 906                 p = arg0;
 907                 STRTODEST(p);
 908                 break;
 909         default:
 910                 if (is_digit(*name)) {
 911                         num = atoi(name);
 912                         if (num > 0 && num <= shellparam.nparam) {
 913                                 p = shellparam.p[num - 1];
 914                                 STRTODEST(p);
 915                         }
 916                 }
 917                 break;
 918         }
 919 }
 920
 921
 922
 923 /*
 924  * Record the the fact that we have to scan this region of the
 925  * string for IFS characters.
 926  */
 927
 928 STATIC void
 929 recordregion(int start, int end, int nulonly)
 930 {
 931         struct ifsregion *ifsp;
 932
 933         if (ifslastp == NULL) {
 934                 ifsp = &ifsfirst;
 935         } else {
 936                 ifsp = (struct ifsregion *)ckmalloc(sizeof (struct ifsregion));
 937                 ifslastp->next = ifsp;
 938         }
 939         ifslastp = ifsp;
 940         ifslastp->next = NULL;
 941         ifslastp->begoff = start;
 942         ifslastp->endoff = end;
 943         ifslastp->nulonly = nulonly;
 944 }
 945
 946
 947
 948 /*
 949  * Break the argument string into pieces based upon IFS and add the
 950  * strings to the argument list.  The regions of the string to be
 951  * searched for IFS characters have been stored by recordregion.
 952  */
 953 STATIC void
 954 ifsbreakup(char *string, struct arglist *arglist)
 955 {
 956         struct ifsregion *ifsp;
 957         struct strlist *sp;
 958         char *start;
 959         char *p;
 960         char *q;
 961         const char *ifs;
 962         int ifsspc;
 963         int nulonly;
 964
 965
 966         start = string;
 967         ifsspc = 0;
 968         nulonly = 0;
 969         if (ifslastp != NULL) {
 970                 ifsp = &ifsfirst;
 971                 do {
 972                         p = string + ifsp->begoff;
 973                         nulonly = ifsp->nulonly;
 974                         ifs = nulonly ? nullstr :
 975                                 ( ifsset() ? ifsval() : " \t\n" );
 976                         ifsspc = 0;
 977                         while (p < string + ifsp->endoff) {
 978                                 q = p;
 979                                 if (*p == CTLESC)
 980                                         p++;
 981                                 if (strchr(ifs, *p)) {
 982                                         if (!nulonly)
 983                                                 ifsspc = (strchr(" \t\n", *p) != NULL);
 984                                         /* Ignore IFS whitespace at start */
 985                                         if (q == start && ifsspc) {
 986                                                 p++;
 987                                                 start = p;
 988                                                 continue;
 989                                         }
 990                                         *q = '\0';
 991                                         sp = (struct strlist *)stalloc(sizeof *sp);
 992                                         sp->text = start;
 993                                         *arglist->lastp = sp;
 994                                         arglist->lastp = &sp->next;
 995                                         p++;
 996                                         if (!nulonly) {
 997                                                 for (;;) {
 998                                                         if (p >= string + ifsp->endoff) {
 999                                                                 break;
1000                                                         }
1001                                                         q = p;
1002                                                         if (*p == CTLESC)
1003                                                                 p++;
1004                                                         if (strchr(ifs, *p) == NULL ) {
1005                                                                 p = q;
1006                                                                 break;
1007                                                         } else if (strchr(" \t\n",*p) == NULL) {
1008                                                                 if (ifsspc) {
1009                                                                         p++;
1010                                                                         ifsspc = 0;
1011                                                                 } else {
1012                                                                         p = q;
1013                                                                         break;
1014                                                                 }
1015                                                         } else
1016                                                                 p++;
1017                                                 }
1018                                         }
1019                                         start = p;
1020                                 } else
1021                                         p++;
1022                         }
1023                 } while ((ifsp = ifsp->next) != NULL);
1024                 if (*start || (!ifsspc && start > string)) {
1025                         sp = (struct strlist *)stalloc(sizeof *sp);
1026                         sp->text = start;
1027                         *arglist->lastp = sp;
1028                         arglist->lastp = &sp->next;
1029                 }
1030         } else {
1031                 sp = (struct strlist *)stalloc(sizeof *sp);
1032                 sp->text = start;
1033                 *arglist->lastp = sp;
1034                 arglist->lastp = &sp->next;
1035         }
1036 }
1037
1038
1039
1040 /*
1041  * Expand shell metacharacters.  At this point, the only control characters
1042  * should be escapes.  The results are stored in the list exparg.
1043  */
1044
1045 STATIC char *expdir;
1046
1047
1048 STATIC void
1049 expandmeta(struct strlist *str, int flag __unused)
1050 {
1051         char *p;
1052         struct strlist **savelastp;
1053         struct strlist *sp;
1054         char c;
1055         /* TODO - EXP_REDIR */
1056
1057         while (str) {
1058                 if (fflag)
1059                         goto nometa;
1060                 p = str->text;
1061                 for (;;) {                      /* fast check for meta chars */
1062                         if ((c = *p++) == '\0')
1063                                 goto nometa;
1064                         if (c == '*' || c == '?' || c == '[' || c == '!')
1065                                 break;
1066                 }
1067                 savelastp = exparg.lastp;
1068                 INTOFF;
1069                 if (expdir == NULL) {
1070                         int i = strlen(str->text);
1071                         expdir = ckmalloc(i < 2048 ? 2048 : i); /* XXX */
1072                 }
1073
1074                 expmeta(expdir, str->text);
1075                 ckfree(expdir);
1076                 expdir = NULL;
1077                 INTON;
1078                 if (exparg.lastp == savelastp) {
1079                         /*
1080                          * no matches
1081                          */
1082 nometa:
1083                         *exparg.lastp = str;
1084                         rmescapes(str->text);
1085                         exparg.lastp = &str->next;
1086                 } else {
1087                         *exparg.lastp = NULL;
1088                         *savelastp = sp = expsort(*savelastp);
1089                         while (sp->next != NULL)
1090                                 sp = sp->next;
1091                         exparg.lastp = &sp->next;
1092                 }
1093                 str = str->next;
1094         }
1095 }
1096
1097
1098 /*
1099  * Do metacharacter (i.e. *, ?, [...]) expansion.
1100  */
1101
1102 STATIC void
1103 expmeta(char *enddir, char *name)
1104 {
1105         char *p;
1106         const char *q;
1107         char *start;
1108         char *endname;
1109         int metaflag;
1110         struct stat statb;
1111         DIR *dirp;
1112         struct dirent *dp;
1113         int atend;
1114         int matchdot;
1115
1116         metaflag = 0;
1117         start = name;
1118         for (p = name ; ; p++) {
1119                 if (*p == '*' || *p == '?')
1120                         metaflag = 1;
1121                 else if (*p == '[') {
1122                         q = p + 1;
1123                         if (*q == '!' || *q == '^')
1124                                 q++;
1125                         for (;;) {
1126                                 while (*q == CTLQUOTEMARK)
1127                                         q++;
1128                                 if (*q == CTLESC)
1129                                         q++;
1130                                 if (*q == '/' || *q == '\0')
1131                                         break;
1132                                 if (*++q == ']') {
1133                                         metaflag = 1;
1134                                         break;
1135                                 }
1136                         }
1137                 } else if (*p == '!' && p[1] == '!'     && (p == name || p[-1] == '/')) {
1138                         metaflag = 1;
1139                 } else if (*p == '\0')
1140                         break;
1141                 else if (*p == CTLQUOTEMARK)
1142                         continue;
1143                 else if (*p == CTLESC)
1144                         p++;
1145                 if (*p == '/') {
1146                         if (metaflag)
1147                                 break;
1148                         start = p + 1;
1149                 }
1150         }
1151         if (metaflag == 0) {    /* we've reached the end of the file name */
1152                 if (enddir != expdir)
1153                         metaflag++;
1154                 for (p = name ; ; p++) {
1155                         if (*p == CTLQUOTEMARK)
1156                                 continue;
1157                         if (*p == CTLESC)
1158                                 p++;
1159                         *enddir++ = *p;
1160                         if (*p == '\0')
1161                                 break;
1162                 }
1163                 if (metaflag == 0 || lstat(expdir, &statb) >= 0)
1164                         addfname(expdir);
1165                 return;
1166         }
1167         endname = p;
1168         if (start != name) {
1169                 p = name;
1170                 while (p < start) {
1171                         while (*p == CTLQUOTEMARK)
1172                                 p++;
1173                         if (*p == CTLESC)
1174                                 p++;
1175                         *enddir++ = *p++;
1176                 }
1177         }
1178         if (enddir == expdir) {
1179                 q = ".";
1180         } else if (enddir == expdir + 1 && *expdir == '/') {
1181                 q = "/";
1182         } else {
1183                 q = expdir;
1184                 enddir[-1] = '\0';
1185         }
1186         if ((dirp = opendir(q)) == NULL)
1187                 return;
1188         if (enddir != expdir)
1189                 enddir[-1] = '/';
1190         if (*endname == 0) {
1191                 atend = 1;
1192         } else {
1193                 atend = 0;
1194                 *endname++ = '\0';
1195         }
1196         matchdot = 0;
1197         p = start;
1198         while (*p == CTLQUOTEMARK)
1199                 p++;
1200         if (*p == CTLESC)
1201                 p++;
1202         if (*p == '.')
1203                 matchdot++;
1204         while (! int_pending() && (dp = readdir(dirp)) != NULL) {
1205                 if (dp->d_name[0] == '.' && ! matchdot)
1206                         continue;
1207                 if (patmatch(start, dp->d_name, 0)) {
1208                         if (atend) {
1209                                 scopy(dp->d_name, enddir);
1210                                 addfname(expdir);
1211                         } else {
1212                                 char *t;
1213                                 for (t = enddir, q = dp->d_name;
1214                                      (*t++ = *q++) != '\0';)
1215                                         continue;
1216                                 t[-1] = '/';
1217                                 expmeta(t, endname);
1218                         }
1219                 }
1220         }
1221         closedir(dirp);
1222         if (! atend)
1223                 endname[-1] = '/';
1224 }
1225
1226
1227 /*
1228  * Add a file name to the list.
1229  */
1230
1231 STATIC void
1232 addfname(char *name)
1233 {
1234         char *p;
1235         struct strlist *sp;
1236
1237         p = stalloc(strlen(name) + 1);
1238         scopy(name, p);
1239         sp = (struct strlist *)stalloc(sizeof *sp);
1240         sp->text = p;
1241         *exparg.lastp = sp;
1242         exparg.lastp = &sp->next;
1243 }
1244
1245
1246 /*
1247  * Sort the results of file name expansion.  It calculates the number of
1248  * strings to sort and then calls msort (short for merge sort) to do the
1249  * work.
1250  */
1251
1252 STATIC struct strlist *
1253 expsort(struct strlist *str)
1254 {
1255         int len;
1256         struct strlist *sp;
1257
1258         len = 0;
1259         for (sp = str ; sp ; sp = sp->next)
1260                 len++;
1261         return msort(str, len);
1262 }
1263
1264
1265 STATIC struct strlist *
1266 msort(struct strlist *list, int len)
1267 {
1268         struct strlist *p, *q = NULL;
1269         struct strlist **lpp;
1270         int half;
1271         int n;
1272
1273         if (len <= 1)
1274                 return list;
1275         half = len >> 1;
1276         p = list;
1277         for (n = half ; --n >= 0 ; ) {
1278                 q = p;
1279                 p = p->next;
1280         }
1281         q->next = NULL;                 /* terminate first half of list */
1282         q = msort(list, half);          /* sort first half of list */
1283         p = msort(p, len - half);               /* sort second half */
1284         lpp = &list;
1285         for (;;) {
1286                 if (strcmp(p->text, q->text) < 0) {
1287                         *lpp = p;
1288                         lpp = &p->next;
1289                         if ((p = *lpp) == NULL) {
1290                                 *lpp = q;
1291                                 break;
1292                         }
1293                 } else {
1294                         *lpp = q;
1295                         lpp = &q->next;
1296                         if ((q = *lpp) == NULL) {
1297                                 *lpp = p;
1298                                 break;
1299                         }
1300                 }
1301         }
1302         return list;
1303 }
1304
1305
1306
1307 /*
1308  * Returns true if the pattern matches the string.
1309  */
1310
1311 int
1312 patmatch(char *pattern, char *string, int squoted)
1313 {
1314 #ifdef notdef
1315         if (pattern[0] == '!' && pattern[1] == '!')
1316                 return 1 - pmatch(pattern + 2, string);
1317         else
1318 #endif
1319                 return pmatch(pattern, string, squoted);
1320 }
1321
1322
1323 STATIC int
1324 pmatch(char *pattern, char *string, int squoted)
1325 {
1326         char *p, *q;
1327         char c;
1328
1329         p = pattern;
1330         q = string;
1331         for (;;) {
1332                 switch (c = *p++) {
1333                 case '\0':
1334                         goto breakloop;
1335                 case CTLESC:
1336                         if (squoted && *q == CTLESC)
1337                                 q++;
1338                         if (*q++ != *p++)
1339                                 return 0;
1340                         break;
1341                 case CTLQUOTEMARK:
1342                         continue;
1343                 case '?':
1344                         if (squoted && *q == CTLESC)
1345                                 q++;
1346                         if (*q++ == '\0')
1347                                 return 0;
1348                         break;
1349                 case '*':
1350                         c = *p;
1351                         while (c == CTLQUOTEMARK || c == '*')
1352                                 c = *++p;
1353                         if (c != CTLESC &&  c != CTLQUOTEMARK &&
1354                             c != '?' && c != '*' && c != '[') {
1355                                 while (*q != c) {
1356                                         if (squoted && *q == CTLESC &&
1357                                             q[1] == c)
1358                                                 break;
1359                                         if (*q == '\0')
1360                                                 return 0;
1361                                         if (squoted && *q == CTLESC)
1362                                                 q++;
1363                                         q++;
1364                                 }
1365                         }
1366                         do {
1367                                 if (pmatch(p, q, squoted))
1368                                         return 1;
1369                                 if (squoted && *q == CTLESC)
1370                                         q++;
1371                         } while (*q++ != '\0');
1372                         return 0;
1373                 case '[': {
1374                         char *endp;
1375                         int invert, found;
1376                         char chr;
1377
1378                         endp = p;
1379                         if (*endp == '!' || *endp == '^')
1380                                 endp++;
1381                         for (;;) {
1382                                 while (*endp == CTLQUOTEMARK)
1383                                         endp++;
1384                                 if (*endp == '\0')
1385                                         goto dft;               /* no matching ] */
1386                                 if (*endp == CTLESC)
1387                                         endp++;
1388                                 if (*++endp == ']')
1389                                         break;
1390                         }
1391                         invert = 0;
1392                         if (*p == '!' || *p == '^') {
1393                                 invert++;
1394                                 p++;
1395                         }
1396                         found = 0;
1397                         chr = *q++;
1398                         if (squoted && chr == CTLESC)
1399                                 chr = *q++;
1400                         if (chr == '\0')
1401                                 return 0;
1402                         c = *p++;
1403                         do {
1404                                 if (c == CTLQUOTEMARK)
1405                                         continue;
1406                                 if (c == CTLESC)
1407                                         c = *p++;
1408                                 if (*p == '-' && p[1] != ']') {
1409                                         p++;
1410                                         while (*p == CTLQUOTEMARK)
1411                                                 p++;
1412                                         if (*p == CTLESC)
1413                                                 p++;
1414                                         if (   collate_range_cmp(chr, c) >= 0
1415                                             && collate_range_cmp(chr, *p) <= 0
1416                                            )
1417                                                 found = 1;
1418                                         p++;
1419                                 } else {
1420                                         if (chr == c)
1421                                                 found = 1;
1422                                 }
1423                         } while ((c = *p++) != ']');
1424                         if (found == invert)
1425                                 return 0;
1426                         break;
1427                 }
1428 dft:            default:
1429                         if (squoted && *q == CTLESC)
1430                                 q++;
1431                         if (*q++ != c)
1432                                 return 0;
1433                         break;
1434                 }
1435         }
1436 breakloop:
1437         if (*q != '\0')
1438                 return 0;
1439         return 1;
1440 }
1441
1442
1443
1444 /*
1445  * Remove any CTLESC characters from a string.
1446  */
1447
1448 void
1449 rmescapes(char *str)
1450 {
1451         char *p, *q;
1452
1453         p = str;
1454         while (*p != CTLESC && *p != CTLQUOTEMARK) {
1455                 if (*p++ == '\0')
1456                         return;
1457         }
1458         q = p;
1459         while (*p) {
1460                 if (*p == CTLQUOTEMARK) {
1461                         p++;
1462                         continue;
1463                 }
1464                 if (*p == CTLESC)
1465                         p++;
1466                 *q++ = *p++;
1467         }
1468         *q = '\0';
1469 }
1470
1471
1472
1473 /*
1474  * See if a pattern matches in a case statement.
1475  */
1476
1477 int
1478 casematch(union node *pattern, char *val)
1479 {
1480         struct stackmark smark;
1481         int result;
1482         char *p;
1483
1484         setstackmark(&smark);
1485         argbackq = pattern->narg.backquote;
1486         STARTSTACKSTR(expdest);
1487         ifslastp = NULL;
1488         argstr(pattern->narg.text, EXP_TILDE | EXP_CASE);
1489         STPUTC('\0', expdest);
1490         p = grabstackstr(expdest);
1491         result = patmatch(p, val, 0);
1492         popstackmark(&smark);
1493         return result;
1494 }
1495
1496 /*
1497  * Our own itoa().
1498  */
1499
1500 STATIC char *
1501 cvtnum(int num, char *buf)
1502 {
1503         char temp[32];
1504         int neg = num < 0;
1505         char *p = temp + 31;
1506
1507         temp[31] = '\0';
1508
1509         do {
1510                 *--p = num % 10 + '0';
1511         } while ((num /= 10) != 0);
1512
1513         if (neg)
1514                 *--p = '-';
1515
1516         while (*p)
1517                 STPUTC(*p++, buf);
1518         return buf;
1519 }
1520
1521 /*
1522  * Do most of the work for wordexp(3).
1523  */
1524
1525 int
1526 wordexpcmd(int argc, char **argv)
1527 {
1528         size_t len;
1529         int i;
1530
1531         out1fmt("%08x", argc - 1);
1532         for (i = 1, len = 0; i < argc; i++)
1533                 len += strlen(argv[i]);
1534         out1fmt("%08x", (int)len);
1535         for (i = 1; i < argc; i++) {
1536                 out1str(argv[i]);
1537                 out1c('\0');
1538         }
1539         return (0);
1540 }