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