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         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 = (unsigned char)*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, subtype, flag);
 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         case VSERROR:
 767                 c = p - var - 1;
 768                 error("${%.*s%s}: Bad substitution", c, var,
 769                     (c > 0 && *p != CTLENDVAR) ? "..." : "");
 770
 771         default:
 772                 abort();
 773         }
 774
 775         if (subtype != VSNORMAL) {      /* skip to end of alternative */
 776                 int nesting = 1;
 777                 for (;;) {
 778                         if ((c = *p++) == CTLESC)
 779                                 p++;
 780                         else if (c == CTLBACKQ || c == (CTLBACKQ|CTLQUOTE)) {
 781                                 if (set)
 782                                         argbackq = argbackq->next;
 783                         } else if (c == CTLVAR) {
 784                                 if ((*p++ & VSTYPE) != VSNORMAL)
 785                                         nesting++;
 786                         } else if (c == CTLENDVAR) {
 787                                 if (--nesting == 0)
 788                                         break;
 789                         }
 790                 }
 791         }
 792         return p;
 793 }
 794
 795
 796
 797 /*
 798  * Test whether a specialized variable is set.
 799  */
 800
 801 STATIC int
 802 varisset(char *name, int nulok)
 803 {
 804
 805         if (*name == '!')
 806                 return backgndpid != -1;
 807         else if (*name == '@' || *name == '*') {
 808                 if (*shellparam.p == NULL)
 809                         return 0;
 810
 811                 if (nulok) {
 812                         char **av;
 813
 814                         for (av = shellparam.p; *av; av++)
 815                                 if (**av != '\0')
 816                                         return 1;
 817                         return 0;
 818                 }
 819         } else if (is_digit(*name)) {
 820                 char *ap;
 821                 int num = atoi(name);
 822
 823                 if (num > shellparam.nparam)
 824                         return 0;
 825
 826                 if (num == 0)
 827                         ap = arg0;
 828                 else
 829                         ap = shellparam.p[num - 1];
 830
 831                 if (nulok && (ap == NULL || *ap == '\0'))
 832                         return 0;
 833         }
 834         return 1;
 835 }
 836
 837
 838
 839 /*
 840  * Add the value of a specialized variable to the stack string.
 841  */
 842
 843 STATIC void
 844 varvalue(char *name, int quoted, int subtype, int flag)
 845 {
 846         int num;
 847         char *p;
 848         int i;
 849         extern int oexitstatus;
 850         char sep;
 851         char **ap;
 852         char const *syntax;
 853
 854 #define STRTODEST(p) \
 855         do {\
 856         if (flag & (EXP_FULL | EXP_CASE) && subtype != VSLENGTH) { \
 857                 syntax = quoted? DQSYNTAX : BASESYNTAX; \
 858                 while (*p) { \
 859                         if (syntax[(int)*p] == CCTL) \
 860                                 STPUTC(CTLESC, expdest); \
 861                         STPUTC(*p++, expdest); \
 862                 } \
 863         } else \
 864                 while (*p) \
 865                         STPUTC(*p++, expdest); \
 866         } while (0)
 867
 868
 869         switch (*name) {
 870         case '$':
 871                 num = rootpid;
 872                 goto numvar;
 873         case '?':
 874                 num = oexitstatus;
 875                 goto numvar;
 876         case '#':
 877                 num = shellparam.nparam;
 878                 goto numvar;
 879         case '!':
 880                 num = backgndpid;
 881 numvar:
 882                 expdest = cvtnum(num, expdest);
 883                 break;
 884         case '-':
 885                 for (i = 0 ; i < NOPTS ; i++) {
 886                         if (optlist[i].val)
 887                                 STPUTC(optlist[i].letter, expdest);
 888                 }
 889                 break;
 890         case '@':
 891                 if (flag & EXP_FULL && quoted) {
 892                         for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
 893                                 STRTODEST(p);
 894                                 if (*ap)
 895                                         STPUTC('\0', expdest);
 896                         }
 897                         break;
 898                 }
 899                 /* FALLTHROUGH */
 900         case '*':
 901                 if (ifsset())
 902                         sep = ifsval()[0];
 903                 else
 904                         sep = ' ';
 905                 for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
 906                         STRTODEST(p);
 907                         if (*ap && sep)
 908                                 STPUTC(sep, expdest);
 909                 }
 910                 break;
 911         case '0':
 912                 p = arg0;
 913                 STRTODEST(p);
 914                 break;
 915         default:
 916                 if (is_digit(*name)) {
 917                         num = atoi(name);
 918                         if (num > 0 && num <= shellparam.nparam) {
 919                                 p = shellparam.p[num - 1];
 920                                 STRTODEST(p);
 921                         }
 922                 }
 923                 break;
 924         }
 925 }
 926
 927
 928
 929 /*
 930  * Record the the fact that we have to scan this region of the
 931  * string for IFS characters.
 932  */
 933
 934 STATIC void
 935 recordregion(int start, int end, int nulonly)
 936 {
 937         struct ifsregion *ifsp;
 938
 939         if (ifslastp == NULL) {
 940                 ifsp = &ifsfirst;
 941         } else {
 942                 ifsp = (struct ifsregion *)ckmalloc(sizeof (struct ifsregion));
 943                 ifslastp->next = ifsp;
 944         }
 945         ifslastp = ifsp;
 946         ifslastp->next = NULL;
 947         ifslastp->begoff = start;
 948         ifslastp->endoff = end;
 949         ifslastp->nulonly = nulonly;
 950 }
 951
 952
 953
 954 /*
 955  * Break the argument string into pieces based upon IFS and add the
 956  * strings to the argument list.  The regions of the string to be
 957  * searched for IFS characters have been stored by recordregion.
 958  */
 959 STATIC void
 960 ifsbreakup(char *string, struct arglist *arglist)
 961 {
 962         struct ifsregion *ifsp;
 963         struct strlist *sp;
 964         char *start;
 965         char *p;
 966         char *q;
 967         char *ifs;
 968         int ifsspc;
 969         int nulonly;
 970
 971
 972         start = string;
 973         ifsspc = 0;
 974         nulonly = 0;
 975         if (ifslastp != NULL) {
 976                 ifsp = &ifsfirst;
 977                 do {
 978                         p = string + ifsp->begoff;
 979                         nulonly = ifsp->nulonly;
 980                         ifs = nulonly ? nullstr :
 981                                 ( ifsset() ? ifsval() : " \t\n" );
 982                         ifsspc = 0;
 983                         while (p < string + ifsp->endoff) {
 984                                 q = p;
 985                                 if (*p == CTLESC)
 986                                         p++;
 987                                 if (strchr(ifs, *p)) {
 988                                         if (!nulonly)
 989                                                 ifsspc = (strchr(" \t\n", *p) != NULL);
 990                                         /* Ignore IFS whitespace at start */
 991                                         if (q == start && ifsspc) {
 992                                                 p++;
 993                                                 start = p;
 994                                                 continue;
 995                                         }
 996                                         *q = '\0';
 997                                         sp = (struct strlist *)stalloc(sizeof *sp);
 998                                         sp->text = start;
 999                                         *arglist->lastp = sp;
1000                                         arglist->lastp = &sp->next;
1001                                         p++;
1002                                         if (!nulonly) {
1003                                                 for (;;) {
1004                                                         if (p >= string + ifsp->endoff) {
1005                                                                 break;
1006                                                         }
1007                                                         q = p;
1008                                                         if (*p == CTLESC)
1009                                                                 p++;
1010                                                         if (strchr(ifs, *p) == NULL ) {
1011                                                                 p = q;
1012                                                                 break;
1013                                                         } else if (strchr(" \t\n",*p) == NULL) {
1014                                                                 if (ifsspc) {
1015                                                                         p++;
1016                                                                         ifsspc = 0;
1017                                                                 } else {
1018                                                                         p = q;
1019                                                                         break;
1020                                                                 }
1021                                                         } else
1022                                                                 p++;
1023                                                 }
1024                                         }
1025                                         start = p;
1026                                 } else
1027                                         p++;
1028                         }
1029                 } while ((ifsp = ifsp->next) != NULL);
1030                 if (*start || (!ifsspc && start > string)) {
1031                         sp = (struct strlist *)stalloc(sizeof *sp);
1032                         sp->text = start;
1033                         *arglist->lastp = sp;
1034                         arglist->lastp = &sp->next;
1035                 }
1036         } else {
1037                 sp = (struct strlist *)stalloc(sizeof *sp);
1038                 sp->text = start;
1039                 *arglist->lastp = sp;
1040                 arglist->lastp = &sp->next;
1041         }
1042 }
1043
1044
1045
1046 /*
1047  * Expand shell metacharacters.  At this point, the only control characters
1048  * should be escapes.  The results are stored in the list exparg.
1049  */
1050
1051 STATIC char *expdir;
1052
1053
1054 STATIC void
1055 expandmeta(struct strlist *str, int flag __unused)
1056 {
1057         char *p;
1058         struct strlist **savelastp;
1059         struct strlist *sp;
1060         char c;
1061         /* TODO - EXP_REDIR */
1062
1063         while (str) {
1064                 if (fflag)
1065                         goto nometa;
1066                 p = str->text;
1067                 for (;;) {                      /* fast check for meta chars */
1068                         if ((c = *p++) == '\0')
1069                                 goto nometa;
1070                         if (c == '*' || c == '?' || c == '[' || c == '!')
1071                                 break;
1072                 }
1073                 savelastp = exparg.lastp;
1074                 INTOFF;
1075                 if (expdir == NULL) {
1076                         int i = strlen(str->text);
1077                         expdir = ckmalloc(i < 2048 ? 2048 : i); /* XXX */
1078                 }
1079
1080                 expmeta(expdir, str->text);
1081                 ckfree(expdir);
1082                 expdir = NULL;
1083                 INTON;
1084                 if (exparg.lastp == savelastp) {
1085                         /*
1086                          * no matches
1087                          */
1088 nometa:
1089                         *exparg.lastp = str;
1090                         rmescapes(str->text);
1091                         exparg.lastp = &str->next;
1092                 } else {
1093                         *exparg.lastp = NULL;
1094                         *savelastp = sp = expsort(*savelastp);
1095                         while (sp->next != NULL)
1096                                 sp = sp->next;
1097                         exparg.lastp = &sp->next;
1098                 }
1099                 str = str->next;
1100         }
1101 }
1102
1103
1104 /*
1105  * Do metacharacter (i.e. *, ?, [...]) expansion.
1106  */
1107
1108 STATIC void
1109 expmeta(char *enddir, char *name)
1110 {
1111         char *p;
1112         char *q;
1113         char *start;
1114         char *endname;
1115         int metaflag;
1116         struct stat statb;
1117         DIR *dirp;
1118         struct dirent *dp;
1119         int atend;
1120         int matchdot;
1121
1122         metaflag = 0;
1123         start = name;
1124         for (p = name ; ; p++) {
1125                 if (*p == '*' || *p == '?')
1126                         metaflag = 1;
1127                 else if (*p == '[') {
1128                         q = p + 1;
1129                         if (*q == '!' || *q == '^')
1130                                 q++;
1131                         for (;;) {
1132                                 while (*q == CTLQUOTEMARK)
1133                                         q++;
1134                                 if (*q == CTLESC)
1135                                         q++;
1136                                 if (*q == '/' || *q == '\0')
1137                                         break;
1138                                 if (*++q == ']') {
1139                                         metaflag = 1;
1140                                         break;
1141                                 }
1142                         }
1143                 } else if (*p == '!' && p[1] == '!'     && (p == name || p[-1] == '/')) {
1144                         metaflag = 1;
1145                 } else if (*p == '\0')
1146                         break;
1147                 else if (*p == CTLQUOTEMARK)
1148                         continue;
1149                 else if (*p == CTLESC)
1150                         p++;
1151                 if (*p == '/') {
1152                         if (metaflag)
1153                                 break;
1154                         start = p + 1;
1155                 }
1156         }
1157         if (metaflag == 0) {    /* we've reached the end of the file name */
1158                 if (enddir != expdir)
1159                         metaflag++;
1160                 for (p = name ; ; p++) {
1161                         if (*p == CTLQUOTEMARK)
1162                                 continue;
1163                         if (*p == CTLESC)
1164                                 p++;
1165                         *enddir++ = *p;
1166                         if (*p == '\0')
1167                                 break;
1168                 }
1169                 if (metaflag == 0 || lstat(expdir, &statb) >= 0)
1170                         addfname(expdir);
1171                 return;
1172         }
1173         endname = p;
1174         if (start != name) {
1175                 p = name;
1176                 while (p < start) {
1177                         while (*p == CTLQUOTEMARK)
1178                                 p++;
1179                         if (*p == CTLESC)
1180                                 p++;
1181                         *enddir++ = *p++;
1182                 }
1183         }
1184         if (enddir == expdir) {
1185                 p = ".";
1186         } else if (enddir == expdir + 1 && *expdir == '/') {
1187                 p = "/";
1188         } else {
1189                 p = expdir;
1190                 enddir[-1] = '\0';
1191         }
1192         if ((dirp = opendir(p)) == NULL)
1193                 return;
1194         if (enddir != expdir)
1195                 enddir[-1] = '/';
1196         if (*endname == 0) {
1197                 atend = 1;
1198         } else {
1199                 atend = 0;
1200                 *endname++ = '\0';
1201         }
1202         matchdot = 0;
1203         p = start;
1204         while (*p == CTLQUOTEMARK)
1205                 p++;
1206         if (*p == CTLESC)
1207                 p++;
1208         if (*p == '.')
1209                 matchdot++;
1210         while (! int_pending() && (dp = readdir(dirp)) != NULL) {
1211                 if (dp->d_name[0] == '.' && ! matchdot)
1212                         continue;
1213                 if (patmatch(start, dp->d_name, 0)) {
1214                         if (atend) {
1215                                 scopy(dp->d_name, enddir);
1216                                 addfname(expdir);
1217                         } else {
1218                                 for (p = enddir, q = dp->d_name;
1219                                      (*p++ = *q++) != '\0';)
1220                                         continue;
1221                                 p[-1] = '/';
1222                                 expmeta(p, endname);
1223                         }
1224                 }
1225         }
1226         closedir(dirp);
1227         if (! atend)
1228                 endname[-1] = '/';
1229 }
1230
1231
1232 /*
1233  * Add a file name to the list.
1234  */
1235
1236 STATIC void
1237 addfname(char *name)
1238 {
1239         char *p;
1240         struct strlist *sp;
1241
1242         p = stalloc(strlen(name) + 1);
1243         scopy(name, p);
1244         sp = (struct strlist *)stalloc(sizeof *sp);
1245         sp->text = p;
1246         *exparg.lastp = sp;
1247         exparg.lastp = &sp->next;
1248 }
1249
1250
1251 /*
1252  * Sort the results of file name expansion.  It calculates the number of
1253  * strings to sort and then calls msort (short for merge sort) to do the
1254  * work.
1255  */
1256
1257 STATIC struct strlist *
1258 expsort(struct strlist *str)
1259 {
1260         int len;
1261         struct strlist *sp;
1262
1263         len = 0;
1264         for (sp = str ; sp ; sp = sp->next)
1265                 len++;
1266         return msort(str, len);
1267 }
1268
1269
1270 STATIC struct strlist *
1271 msort(struct strlist *list, int len)
1272 {
1273         struct strlist *p, *q = NULL;
1274         struct strlist **lpp;
1275         int half;
1276         int n;
1277
1278         if (len <= 1)
1279                 return list;
1280         half = len >> 1;
1281         p = list;
1282         for (n = half ; --n >= 0 ; ) {
1283                 q = p;
1284                 p = p->next;
1285         }
1286         q->next = NULL;                 /* terminate first half of list */
1287         q = msort(list, half);          /* sort first half of list */
1288         p = msort(p, len - half);               /* sort second half */
1289         lpp = &list;
1290         for (;;) {
1291                 if (strcmp(p->text, q->text) < 0) {
1292                         *lpp = p;
1293                         lpp = &p->next;
1294                         if ((p = *lpp) == NULL) {
1295                                 *lpp = q;
1296                                 break;
1297                         }
1298                 } else {
1299                         *lpp = q;
1300                         lpp = &q->next;
1301                         if ((q = *lpp) == NULL) {
1302                                 *lpp = p;
1303                                 break;
1304                         }
1305                 }
1306         }
1307         return list;
1308 }
1309
1310
1311
1312 /*
1313  * Returns true if the pattern matches the string.
1314  */
1315
1316 int
1317 patmatch(char *pattern, char *string, int squoted)
1318 {
1319 #ifdef notdef
1320         if (pattern[0] == '!' && pattern[1] == '!')
1321                 return 1 - pmatch(pattern + 2, string);
1322         else
1323 #endif
1324                 return pmatch(pattern, string, squoted);
1325 }
1326
1327
1328 STATIC int
1329 pmatch(char *pattern, char *string, int squoted)
1330 {
1331         char *p, *q;
1332         char c;
1333
1334         p = pattern;
1335         q = string;
1336         for (;;) {
1337                 switch (c = *p++) {
1338                 case '\0':
1339                         goto breakloop;
1340                 case CTLESC:
1341                         if (squoted && *q == CTLESC)
1342                                 q++;
1343                         if (*q++ != *p++)
1344                                 return 0;
1345                         break;
1346                 case CTLQUOTEMARK:
1347                         continue;
1348                 case '?':
1349                         if (squoted && *q == CTLESC)
1350                                 q++;
1351                         if (*q++ == '\0')
1352                                 return 0;
1353                         break;
1354                 case '*':
1355                         c = *p;
1356                         while (c == CTLQUOTEMARK || c == '*')
1357                                 c = *++p;
1358                         if (c != CTLESC &&  c != CTLQUOTEMARK &&
1359                             c != '?' && c != '*' && c != '[') {
1360                                 while (*q != c) {
1361                                         if (squoted && *q == CTLESC &&
1362                                             q[1] == c)
1363                                                 break;
1364                                         if (*q == '\0')
1365                                                 return 0;
1366                                         if (squoted && *q == CTLESC)
1367                                                 q++;
1368                                         q++;
1369                                 }
1370                         }
1371                         do {
1372                                 if (pmatch(p, q, squoted))
1373                                         return 1;
1374                                 if (squoted && *q == CTLESC)
1375                                         q++;
1376                         } while (*q++ != '\0');
1377                         return 0;
1378                 case '[': {
1379                         char *endp;
1380                         int invert, found;
1381                         char chr;
1382
1383                         endp = p;
1384                         if (*endp == '!' || *endp == '^')
1385                                 endp++;
1386                         for (;;) {
1387                                 while (*endp == CTLQUOTEMARK)
1388                                         endp++;
1389                                 if (*endp == '\0')
1390                                         goto dft;               /* no matching ] */
1391                                 if (*endp == CTLESC)
1392                                         endp++;
1393                                 if (*++endp == ']')
1394                                         break;
1395                         }
1396                         invert = 0;
1397                         if (*p == '!' || *p == '^') {
1398                                 invert++;
1399                                 p++;
1400                         }
1401                         found = 0;
1402                         chr = *q++;
1403                         if (squoted && chr == CTLESC)
1404                                 chr = *q++;
1405                         if (chr == '\0')
1406                                 return 0;
1407                         c = *p++;
1408                         do {
1409                                 if (c == CTLQUOTEMARK)
1410                                         continue;
1411                                 if (c == CTLESC)
1412                                         c = *p++;
1413                                 if (*p == '-' && p[1] != ']') {
1414                                         p++;
1415                                         while (*p == CTLQUOTEMARK)
1416                                                 p++;
1417                                         if (*p == CTLESC)
1418                                                 p++;
1419                                         if (   collate_range_cmp(chr, c) >= 0
1420                                             && collate_range_cmp(chr, *p) <= 0
1421                                            )
1422                                                 found = 1;
1423                                         p++;
1424                                 } else {
1425                                         if (chr == c)
1426                                                 found = 1;
1427                                 }
1428                         } while ((c = *p++) != ']');
1429                         if (found == invert)
1430                                 return 0;
1431                         break;
1432                 }
1433 dft:            default:
1434                         if (squoted && *q == CTLESC)
1435                                 q++;
1436                         if (*q++ != c)
1437                                 return 0;
1438                         break;
1439                 }
1440         }
1441 breakloop:
1442         if (*q != '\0')
1443                 return 0;
1444         return 1;
1445 }
1446
1447
1448
1449 /*
1450  * Remove any CTLESC characters from a string.
1451  */
1452
1453 void
1454 rmescapes(char *str)
1455 {
1456         char *p, *q;
1457
1458         p = str;
1459         while (*p != CTLESC && *p != CTLQUOTEMARK) {
1460                 if (*p++ == '\0')
1461                         return;
1462         }
1463         q = p;
1464         while (*p) {
1465                 if (*p == CTLQUOTEMARK) {
1466                         p++;
1467                         continue;
1468                 }
1469                 if (*p == CTLESC)
1470                         p++;
1471                 *q++ = *p++;
1472         }
1473         *q = '\0';
1474 }
1475
1476
1477
1478 /*
1479  * See if a pattern matches in a case statement.
1480  */
1481
1482 int
1483 casematch(union node *pattern, char *val)
1484 {
1485         struct stackmark smark;
1486         int result;
1487         char *p;
1488
1489         setstackmark(&smark);
1490         argbackq = pattern->narg.backquote;
1491         STARTSTACKSTR(expdest);
1492         ifslastp = NULL;
1493         argstr(pattern->narg.text, EXP_TILDE | EXP_CASE);
1494         STPUTC('\0', expdest);
1495         p = grabstackstr(expdest);
1496         result = patmatch(p, val, 0);
1497         popstackmark(&smark);
1498         return result;
1499 }
1500
1501 /*
1502  * Our own itoa().
1503  */
1504
1505 STATIC char *
1506 cvtnum(int num, char *buf)
1507 {
1508         char temp[32];
1509         int neg = num < 0;
1510         char *p = temp + 31;
1511
1512         temp[31] = '\0';
1513
1514         do {
1515                 *--p = num % 10 + '0';
1516         } while ((num /= 10) != 0);
1517
1518         if (neg)
1519                 *--p = '-';
1520
1521         while (*p)
1522                 STPUTC(*p++, buf);
1523         return buf;
1524 }
1525
1526 /*
1527  * Do most of the work for wordexp(3).
1528  */
1529
1530 int
1531 wordexpcmd(int argc, char **argv)
1532 {
1533         size_t len;
1534         int i;
1535
1536         out1fmt("%08x", argc - 1);
1537         for (i = 1, len = 0; i < argc; i++)
1538                 len += strlen(argv[i]);
1539         out1fmt("%08x", (int)len);
1540         for (i = 1; i < argc; i++) {
1541                 out1str(argv[i]);
1542                 out1c('\0');
1543         }
1544         return (0);
1545 }