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);
 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         int 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 #if INT_MAX / 1000000000 >= 10 || INT_MIN / 1000000000 <= -10
 376 #error "integers with more than 10 digits are not supported"
 377 #endif
 378         CHECKSTRSPACE(12 - 2, expdest);
 379         USTPUTC('\0', expdest);
 380         start = stackblock();
 381         p = expdest - 2;
 382         while (p >= start && *p != CTLARI)
 383                 --p;
 384         if (p < start || *p != CTLARI)
 385                 error("missing CTLARI (shouldn't happen)");
 386         if (p > start && *(p - 1) == CTLESC)
 387                 for (p = start; *p != CTLARI; p++)
 388                         if (*p == CTLESC)
 389                                 p++;
 390
 391         if (p[1] == '"')
 392                 quoted=1;
 393         else
 394                 quoted=0;
 395         begoff = p - start;
 396         removerecordregions(begoff);
 397         if (quotes)
 398                 rmescapes(p+2);
 399         result = arith(p+2);
 400         fmtstr(p, 12, "%d", result);
 401         while (*p++)
 402                 ;
 403         if (quoted == 0)
 404                 recordregion(begoff, p - 1 - start, 0);
 405         result = expdest - p + 1;
 406         STADJUST(-result, expdest);
 407 }
 408
 409
 410 /*
 411  * Expand stuff in backwards quotes.
 412  */
 413
 414 STATIC void
 415 expbackq(union node *cmd, int quoted, int flag)
 416 {
 417         struct backcmd in;
 418         int i;
 419         char buf[128];
 420         char *p;
 421         char *dest = expdest;
 422         struct ifsregion saveifs, *savelastp;
 423         struct nodelist *saveargbackq;
 424         char lastc;
 425         int startloc = dest - stackblock();
 426         char const *syntax = quoted? DQSYNTAX : BASESYNTAX;
 427         int saveherefd;
 428         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 429         int nnl;
 430
 431         INTOFF;
 432         saveifs = ifsfirst;
 433         savelastp = ifslastp;
 434         saveargbackq = argbackq;
 435         saveherefd = herefd;
 436         herefd = -1;
 437         p = grabstackstr(dest);
 438         evalbackcmd(cmd, &in);
 439         ungrabstackstr(p, dest);
 440         ifsfirst = saveifs;
 441         ifslastp = savelastp;
 442         argbackq = saveargbackq;
 443         herefd = saveherefd;
 444
 445         p = in.buf;
 446         lastc = '\0';
 447         nnl = 0;
 448         /* Don't copy trailing newlines */
 449         for (;;) {
 450                 if (--in.nleft < 0) {
 451                         if (in.fd < 0)
 452                                 break;
 453                         while ((i = read(in.fd, buf, sizeof buf)) < 0 && errno == EINTR);
 454                         TRACE(("expbackq: read returns %d\n", i));
 455                         if (i <= 0)
 456                                 break;
 457                         p = buf;
 458                         in.nleft = i - 1;
 459                 }
 460                 lastc = *p++;
 461                 if (lastc != '\0') {
 462                         if (quotes && syntax[(int)lastc] == CCTL)
 463                                 STPUTC(CTLESC, dest);
 464                         if (lastc == '\n') {
 465                                 nnl++;
 466                         } else {
 467                                 while (nnl > 0) {
 468                                         nnl--;
 469                                         STPUTC('\n', dest);
 470                                 }
 471                                 STPUTC(lastc, dest);
 472                         }
 473                 }
 474         }
 475
 476         if (in.fd >= 0)
 477                 close(in.fd);
 478         if (in.buf)
 479                 ckfree(in.buf);
 480         if (in.jp)
 481                 exitstatus = waitforjob(in.jp, (int *)NULL);
 482         if (quoted == 0)
 483                 recordregion(startloc, dest - stackblock(), 0);
 484         TRACE(("evalbackq: size=%d: \"%.*s\"\n",
 485                 (dest - stackblock()) - startloc,
 486                 (dest - stackblock()) - startloc,
 487                 stackblock() + startloc));
 488         expdest = dest;
 489         INTON;
 490 }
 491
 492
 493
 494 STATIC int
 495 subevalvar(char *p, char *str, int strloc, int subtype, int startloc,
 496   int varflags)
 497 {
 498         char *startp;
 499         char *loc = NULL;
 500         char *q;
 501         int c = 0;
 502         int saveherefd = herefd;
 503         struct nodelist *saveargbackq = argbackq;
 504         int amount;
 505
 506         herefd = -1;
 507         argstr(p, 0);
 508         STACKSTRNUL(expdest);
 509         herefd = saveherefd;
 510         argbackq = saveargbackq;
 511         startp = stackblock() + startloc;
 512         if (str == NULL)
 513             str = stackblock() + strloc;
 514
 515         switch (subtype) {
 516         case VSASSIGN:
 517                 setvar(str, startp, 0);
 518                 amount = startp - expdest;
 519                 STADJUST(amount, expdest);
 520                 varflags &= ~VSNUL;
 521                 if (c != 0)
 522                         *loc = c;
 523                 return 1;
 524
 525         case VSQUESTION:
 526                 if (*p != CTLENDVAR) {
 527                         outfmt(&errout, "%s\n", startp);
 528                         error((char *)NULL);
 529                 }
 530                 error("%.*s: parameter %snot set", (int)(p - str - 1),
 531                       str, (varflags & VSNUL) ? "null or "
 532                                               : nullstr);
 533                 return 0;
 534
 535         case VSTRIMLEFT:
 536                 for (loc = startp; loc < str; loc++) {
 537                         c = *loc;
 538                         *loc = '\0';
 539                         if (patmatch(str, startp, varflags & VSQUOTE)) {
 540                                 *loc = c;
 541                                 goto recordleft;
 542                         }
 543                         *loc = c;
 544                         if ((varflags & VSQUOTE) && *loc == CTLESC)
 545                                 loc++;
 546                 }
 547                 return 0;
 548
 549         case VSTRIMLEFTMAX:
 550                 for (loc = str - 1; loc >= startp;) {
 551                         c = *loc;
 552                         *loc = '\0';
 553                         if (patmatch(str, startp, varflags & VSQUOTE)) {
 554                                 *loc = c;
 555                                 goto recordleft;
 556                         }
 557                         *loc = c;
 558                         loc--;
 559                         if ((varflags & VSQUOTE) && loc > startp &&
 560                             *(loc - 1) == CTLESC) {
 561                                 for (q = startp; q < loc; q++)
 562                                         if (*q == CTLESC)
 563                                                 q++;
 564                                 if (q > loc)
 565                                         loc--;
 566                         }
 567                 }
 568                 return 0;
 569
 570         case VSTRIMRIGHT:
 571                 for (loc = str - 1; loc >= startp;) {
 572                         if (patmatch(str, loc, varflags & VSQUOTE)) {
 573                                 amount = loc - expdest;
 574                                 STADJUST(amount, expdest);
 575                                 return 1;
 576                         }
 577                         loc--;
 578                         if ((varflags & VSQUOTE) && loc > startp &&
 579                             *(loc - 1) == CTLESC) {
 580                                 for (q = startp; q < loc; q++)
 581                                         if (*q == CTLESC)
 582                                                 q++;
 583                                 if (q > loc)
 584                                         loc--;
 585                         }
 586                 }
 587                 return 0;
 588
 589         case VSTRIMRIGHTMAX:
 590                 for (loc = startp; loc < str - 1; loc++) {
 591                         if (patmatch(str, loc, varflags & VSQUOTE)) {
 592                                 amount = loc - expdest;
 593                                 STADJUST(amount, expdest);
 594                                 return 1;
 595                         }
 596                         if ((varflags & VSQUOTE) && *loc == CTLESC)
 597                                 loc++;
 598                 }
 599                 return 0;
 600
 601
 602         default:
 603                 abort();
 604         }
 605
 606 recordleft:
 607         amount = ((str - 1) - (loc - startp)) - expdest;
 608         STADJUST(amount, expdest);
 609         while (loc != str - 1)
 610                 *startp++ = *loc++;
 611         return 1;
 612 }
 613
 614
 615 /*
 616  * Expand a variable, and return a pointer to the next character in the
 617  * input string.
 618  */
 619
 620 STATIC char *
 621 evalvar(char *p, int flag)
 622 {
 623         int subtype;
 624         int varflags;
 625         char *var;
 626         char *val;
 627         int patloc;
 628         int c;
 629         int set;
 630         int special;
 631         int startloc;
 632         int varlen;
 633         int easy;
 634         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 635
 636         varflags = *p++;
 637         subtype = varflags & VSTYPE;
 638         var = p;
 639         special = 0;
 640         if (! is_name(*p))
 641                 special = 1;
 642         p = strchr(p, '=') + 1;
 643 again: /* jump here after setting a variable with ${var=text} */
 644         if (special) {
 645                 set = varisset(var, varflags & VSNUL);
 646                 val = NULL;
 647         } else {
 648                 val = bltinlookup(var, 1);
 649                 if (val == NULL || ((varflags & VSNUL) && val[0] == '\0')) {
 650                         val = NULL;
 651                         set = 0;
 652                 } else
 653                         set = 1;
 654         }
 655         varlen = 0;
 656         startloc = expdest - stackblock();
 657         if (!set && uflag) {
 658                 switch (subtype) {
 659                 case VSNORMAL:
 660                 case VSTRIMLEFT:
 661                 case VSTRIMLEFTMAX:
 662                 case VSTRIMRIGHT:
 663                 case VSTRIMRIGHTMAX:
 664                 case VSLENGTH:
 665                         error("%.*s: parameter not set", (int)(p - var - 1),
 666                             var);
 667                 }
 668         }
 669         if (set && subtype != VSPLUS) {
 670                 /* insert the value of the variable */
 671                 if (special) {
 672                         varvalue(var, varflags & VSQUOTE, flag & EXP_FULL);
 673                         if (subtype == VSLENGTH) {
 674                                 varlen = expdest - stackblock() - startloc;
 675                                 STADJUST(-varlen, expdest);
 676                         }
 677                 } else {
 678                         char const *syntax = (varflags & VSQUOTE) ? DQSYNTAX
 679                                                                   : BASESYNTAX;
 680
 681                         if (subtype == VSLENGTH) {
 682                                 for (;*val; val++)
 683                                         varlen++;
 684                         }
 685                         else {
 686                                 while (*val) {
 687                                         if (quotes &&
 688                                             syntax[(int)*val] == CCTL)
 689                                                 STPUTC(CTLESC, expdest);
 690                                         STPUTC(*val++, expdest);
 691                                 }
 692
 693                         }
 694                 }
 695         }
 696
 697         if (subtype == VSPLUS)
 698                 set = ! set;
 699
 700         easy = ((varflags & VSQUOTE) == 0 ||
 701                 (*var == '@' && shellparam.nparam != 1));
 702
 703
 704         switch (subtype) {
 705         case VSLENGTH:
 706                 expdest = cvtnum(varlen, expdest);
 707                 goto record;
 708
 709         case VSNORMAL:
 710                 if (!easy)
 711                         break;
 712 record:
 713                 recordregion(startloc, expdest - stackblock(),
 714                              varflags & VSQUOTE);
 715                 break;
 716
 717         case VSPLUS:
 718         case VSMINUS:
 719                 if (!set) {
 720                         argstr(p, flag);
 721                         break;
 722                 }
 723                 if (easy)
 724                         goto record;
 725                 break;
 726
 727         case VSTRIMLEFT:
 728         case VSTRIMLEFTMAX:
 729         case VSTRIMRIGHT:
 730         case VSTRIMRIGHTMAX:
 731                 if (!set)
 732                         break;
 733                 /*
 734                  * Terminate the string and start recording the pattern
 735                  * right after it
 736                  */
 737                 STPUTC('\0', expdest);
 738                 patloc = expdest - stackblock();
 739                 if (subevalvar(p, NULL, patloc, subtype,
 740                                startloc, varflags) == 0) {
 741                         int amount = (expdest - stackblock() - patloc) + 1;
 742                         STADJUST(-amount, expdest);
 743                 }
 744                 /* Remove any recorded regions beyond start of variable */
 745                 removerecordregions(startloc);
 746                 goto record;
 747
 748         case VSASSIGN:
 749         case VSQUESTION:
 750                 if (!set) {
 751                         if (subevalvar(p, var, 0, subtype, startloc, varflags)) {
 752                                 varflags &= ~VSNUL;
 753                                 /*
 754                                  * Remove any recorded regions beyond
 755                                  * start of variable
 756                                  */
 757                                 removerecordregions(startloc);
 758                                 goto again;
 759                         }
 760                         break;
 761                 }
 762                 if (easy)
 763                         goto record;
 764                 break;
 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 allow_split)
 840 {
 841         int num;
 842         char *p;
 843         int i;
 844         extern int oexitstatus;
 845         char sep;
 846         char **ap;
 847         char const *syntax;
 848
 849 #define STRTODEST(p) \
 850         do {\
 851         if (allow_split) { \
 852                 syntax = quoted? DQSYNTAX : BASESYNTAX; \
 853                 while (*p) { \
 854                         if (syntax[(int)*p] == CCTL) \
 855                                 STPUTC(CTLESC, expdest); \
 856                         STPUTC(*p++, expdest); \
 857                 } \
 858         } else \
 859                 while (*p) \
 860                         STPUTC(*p++, expdest); \
 861         } while (0)
 862
 863
 864         switch (*name) {
 865         case '$':
 866                 num = rootpid;
 867                 goto numvar;
 868         case '?':
 869                 num = oexitstatus;
 870                 goto numvar;
 871         case '#':
 872                 num = shellparam.nparam;
 873                 goto numvar;
 874         case '!':
 875                 num = backgndpid;
 876 numvar:
 877                 expdest = cvtnum(num, expdest);
 878                 break;
 879         case '-':
 880                 for (i = 0 ; i < NOPTS ; i++) {
 881                         if (optlist[i].val)
 882                                 STPUTC(optlist[i].letter, expdest);
 883                 }
 884                 break;
 885         case '@':
 886                 if (allow_split && quoted) {
 887                         for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
 888                                 STRTODEST(p);
 889                                 if (*ap)
 890                                         STPUTC('\0', expdest);
 891                         }
 892                         break;
 893                 }
 894                 /* FALLTHROUGH */
 895         case '*':
 896                 if (ifsset())
 897                         sep = ifsval()[0];
 898                 else
 899                         sep = ' ';
 900                 for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
 901                         STRTODEST(p);
 902                         if (*ap && sep)
 903                                 STPUTC(sep, expdest);
 904                 }
 905                 break;
 906         case '0':
 907                 p = arg0;
 908                 STRTODEST(p);
 909                 break;
 910         default:
 911                 if (is_digit(*name)) {
 912                         num = atoi(name);
 913                         if (num > 0 && num <= shellparam.nparam) {
 914                                 p = shellparam.p[num - 1];
 915                                 STRTODEST(p);
 916                         }
 917                 }
 918                 break;
 919         }
 920 }
 921
 922
 923
 924 /*
 925  * Record the the fact that we have to scan this region of the
 926  * string for IFS characters.
 927  */
 928
 929 STATIC void
 930 recordregion(int start, int end, int nulonly)
 931 {
 932         struct ifsregion *ifsp;
 933
 934         if (ifslastp == NULL) {
 935                 ifsp = &ifsfirst;
 936         } else {
 937                 ifsp = (struct ifsregion *)ckmalloc(sizeof (struct ifsregion));
 938                 ifslastp->next = ifsp;
 939         }
 940         ifslastp = ifsp;
 941         ifslastp->next = NULL;
 942         ifslastp->begoff = start;
 943         ifslastp->endoff = end;
 944         ifslastp->nulonly = nulonly;
 945 }
 946
 947
 948
 949 /*
 950  * Break the argument string into pieces based upon IFS and add the
 951  * strings to the argument list.  The regions of the string to be
 952  * searched for IFS characters have been stored by recordregion.
 953  */
 954 STATIC void
 955 ifsbreakup(char *string, struct arglist *arglist)
 956 {
 957         struct ifsregion *ifsp;
 958         struct strlist *sp;
 959         char *start;
 960         char *p;
 961         char *q;
 962         char *ifs;
 963         int ifsspc;
 964         int nulonly;
 965
 966
 967         start = string;
 968         ifsspc = 0;
 969         nulonly = 0;
 970         if (ifslastp != NULL) {
 971                 ifsp = &ifsfirst;
 972                 do {
 973                         p = string + ifsp->begoff;
 974                         nulonly = ifsp->nulonly;
 975                         ifs = nulonly ? nullstr :
 976                                 ( ifsset() ? ifsval() : " \t\n" );
 977                         ifsspc = 0;
 978                         while (p < string + ifsp->endoff) {
 979                                 q = p;
 980                                 if (*p == CTLESC)
 981                                         p++;
 982                                 if (strchr(ifs, *p)) {
 983                                         if (!nulonly)
 984                                                 ifsspc = (strchr(" \t\n", *p) != NULL);
 985                                         /* Ignore IFS whitespace at start */
 986                                         if (q == start && ifsspc) {
 987                                                 p++;
 988                                                 start = p;
 989                                                 continue;
 990                                         }
 991                                         *q = '\0';
 992                                         sp = (struct strlist *)stalloc(sizeof *sp);
 993                                         sp->text = start;
 994                                         *arglist->lastp = sp;
 995                                         arglist->lastp = &sp->next;
 996                                         p++;
 997                                         if (!nulonly) {
 998                                                 for (;;) {
 999                                                         if (p >= string + ifsp->endoff) {
1000                                                                 break;
1001                                                         }
1002                                                         q = p;
1003                                                         if (*p == CTLESC)
1004                                                                 p++;
1005                                                         if (strchr(ifs, *p) == NULL ) {
1006                                                                 p = q;
1007                                                                 break;
1008                                                         } else if (strchr(" \t\n",*p) == NULL) {
1009                                                                 if (ifsspc) {
1010                                                                         p++;
1011                                                                         ifsspc = 0;
1012                                                                 } else {
1013                                                                         p = q;
1014                                                                         break;
1015                                                                 }
1016                                                         } else
1017                                                                 p++;
1018                                                 }
1019                                         }
1020                                         start = p;
1021                                 } else
1022                                         p++;
1023                         }
1024                 } while ((ifsp = ifsp->next) != NULL);
1025                 if (*start || (!ifsspc && start > string)) {
1026                         sp = (struct strlist *)stalloc(sizeof *sp);
1027                         sp->text = start;
1028                         *arglist->lastp = sp;
1029                         arglist->lastp = &sp->next;
1030                 }
1031         } else {
1032                 sp = (struct strlist *)stalloc(sizeof *sp);
1033                 sp->text = start;
1034                 *arglist->lastp = sp;
1035                 arglist->lastp = &sp->next;
1036         }
1037 }
1038
1039
1040
1041 /*
1042  * Expand shell metacharacters.  At this point, the only control characters
1043  * should be escapes.  The results are stored in the list exparg.
1044  */
1045
1046 STATIC char *expdir;
1047
1048
1049 STATIC void
1050 expandmeta(struct strlist *str, int flag __unused)
1051 {
1052         char *p;
1053         struct strlist **savelastp;
1054         struct strlist *sp;
1055         char c;
1056         /* TODO - EXP_REDIR */
1057
1058         while (str) {
1059                 if (fflag)
1060                         goto nometa;
1061                 p = str->text;
1062                 for (;;) {                      /* fast check for meta chars */
1063                         if ((c = *p++) == '\0')
1064                                 goto nometa;
1065                         if (c == '*' || c == '?' || c == '[' || c == '!')
1066                                 break;
1067                 }
1068                 savelastp = exparg.lastp;
1069                 INTOFF;
1070                 if (expdir == NULL) {
1071                         int i = strlen(str->text);
1072                         expdir = ckmalloc(i < 2048 ? 2048 : i); /* XXX */
1073                 }
1074
1075                 expmeta(expdir, str->text);
1076                 ckfree(expdir);
1077                 expdir = NULL;
1078                 INTON;
1079                 if (exparg.lastp == savelastp) {
1080                         /*
1081                          * no matches
1082                          */
1083 nometa:
1084                         *exparg.lastp = str;
1085                         rmescapes(str->text);
1086                         exparg.lastp = &str->next;
1087                 } else {
1088                         *exparg.lastp = NULL;
1089                         *savelastp = sp = expsort(*savelastp);
1090                         while (sp->next != NULL)
1091                                 sp = sp->next;
1092                         exparg.lastp = &sp->next;
1093                 }
1094                 str = str->next;
1095         }
1096 }
1097
1098
1099 /*
1100  * Do metacharacter (i.e. *, ?, [...]) expansion.
1101  */
1102
1103 STATIC void
1104 expmeta(char *enddir, char *name)
1105 {
1106         char *p;
1107         char *q;
1108         char *start;
1109         char *endname;
1110         int metaflag;
1111         struct stat statb;
1112         DIR *dirp;
1113         struct dirent *dp;
1114         int atend;
1115         int matchdot;
1116
1117         metaflag = 0;
1118         start = name;
1119         for (p = name ; ; p++) {
1120                 if (*p == '*' || *p == '?')
1121                         metaflag = 1;
1122                 else if (*p == '[') {
1123                         q = p + 1;
1124                         if (*q == '!' || *q == '^')
1125                                 q++;
1126                         for (;;) {
1127                                 while (*q == CTLQUOTEMARK)
1128                                         q++;
1129                                 if (*q == CTLESC)
1130                                         q++;
1131                                 if (*q == '/' || *q == '\0')
1132                                         break;
1133                                 if (*++q == ']') {
1134                                         metaflag = 1;
1135                                         break;
1136                                 }
1137                         }
1138                 } else if (*p == '!' && p[1] == '!'     && (p == name || p[-1] == '/')) {
1139                         metaflag = 1;
1140                 } else if (*p == '\0')
1141                         break;
1142                 else if (*p == CTLQUOTEMARK)
1143                         continue;
1144                 else if (*p == CTLESC)
1145                         p++;
1146                 if (*p == '/') {
1147                         if (metaflag)
1148                                 break;
1149                         start = p + 1;
1150                 }
1151         }
1152         if (metaflag == 0) {    /* we've reached the end of the file name */
1153                 if (enddir != expdir)
1154                         metaflag++;
1155                 for (p = name ; ; p++) {
1156                         if (*p == CTLQUOTEMARK)
1157                                 continue;
1158                         if (*p == CTLESC)
1159                                 p++;
1160                         *enddir++ = *p;
1161                         if (*p == '\0')
1162                                 break;
1163                 }
1164                 if (metaflag == 0 || lstat(expdir, &statb) >= 0)
1165                         addfname(expdir);
1166                 return;
1167         }
1168         endname = p;
1169         if (start != name) {
1170                 p = name;
1171                 while (p < start) {
1172                         while (*p == CTLQUOTEMARK)
1173                                 p++;
1174                         if (*p == CTLESC)
1175                                 p++;
1176                         *enddir++ = *p++;
1177                 }
1178         }
1179         if (enddir == expdir) {
1180                 p = ".";
1181         } else if (enddir == expdir + 1 && *expdir == '/') {
1182                 p = "/";
1183         } else {
1184                 p = expdir;
1185                 enddir[-1] = '\0';
1186         }
1187         if ((dirp = opendir(p)) == NULL)
1188                 return;
1189         if (enddir != expdir)
1190                 enddir[-1] = '/';
1191         if (*endname == 0) {
1192                 atend = 1;
1193         } else {
1194                 atend = 0;
1195                 *endname++ = '\0';
1196         }
1197         matchdot = 0;
1198         p = start;
1199         while (*p == CTLQUOTEMARK)
1200                 p++;
1201         if (*p == CTLESC)
1202                 p++;
1203         if (*p == '.')
1204                 matchdot++;
1205         while (! int_pending() && (dp = readdir(dirp)) != NULL) {
1206                 if (dp->d_name[0] == '.' && ! matchdot)
1207                         continue;
1208                 if (patmatch(start, dp->d_name, 0)) {
1209                         if (atend) {
1210                                 scopy(dp->d_name, enddir);
1211                                 addfname(expdir);
1212                         } else {
1213                                 for (p = enddir, q = dp->d_name;
1214                                      (*p++ = *q++) != '\0';)
1215                                         continue;
1216                                 p[-1] = '/';
1217                                 expmeta(p, 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 }