bin/sh/expand.c

   1 /*-
   2  * Copyright (c) 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Kenneth Almquist.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  */
  36
  37 #ifndef lint
  38 #if 0
  39 static char sccsid[] = "@(#)expand.c    8.5 (Berkeley) 5/15/95";
  40 #endif
  41 static const char rcsid[] =
  42         "$Id: expand.c,v 1.23 1998/09/06 21:13:09 tegge Exp $";
  43 #endif /* not lint */
  44
  45 #include <sys/types.h>
  46 #include <sys/time.h>
  47 #include <sys/stat.h>
  48 #include <errno.h>
  49 #include <dirent.h>
  50 #include <unistd.h>
  51 #include <pwd.h>
  52 #include <stdlib.h>
  53 #include <limits.h>
  54 #include <stdio.h>
  55
  56 /*
  57  * Routines to expand arguments to commands.  We have to deal with
  58  * backquotes, shell variables, and file metacharacters.
  59  */
  60
  61 #include "shell.h"
  62 #include "main.h"
  63 #include "nodes.h"
  64 #include "eval.h"
  65 #include "expand.h"
  66 #include "syntax.h"
  67 #include "parser.h"
  68 #include "jobs.h"
  69 #include "options.h"
  70 #include "var.h"
  71 #include "input.h"
  72 #include "output.h"
  73 #include "memalloc.h"
  74 #include "error.h"
  75 #include "mystring.h"
  76 #include "arith.h"
  77 #include "show.h"
  78
  79 /*
  80  * Structure specifying which parts of the string should be searched
  81  * for IFS characters.
  82  */
  83
  84 struct ifsregion {
  85         struct ifsregion *next; /* next region in list */
  86         int begoff;             /* offset of start of region */
  87         int endoff;             /* offset of end of region */
  88         int nulonly;            /* search for nul bytes only */
  89 };
  90
  91
  92 char *expdest;                  /* output of current string */
  93 struct nodelist *argbackq;      /* list of back quote expressions */
  94 struct ifsregion ifsfirst;      /* first struct in list of ifs regions */
  95 struct ifsregion *ifslastp;     /* last struct in list */
  96 struct arglist exparg;          /* holds expanded arg list */
  97
  98 STATIC void argstr __P((char *, int));
  99 STATIC char *exptilde __P((char *, int));
 100 STATIC void expbackq __P((union node *, int, int));
 101 STATIC int subevalvar __P((char *, char *, int, int, int, int));
 102 STATIC char *evalvar __P((char *, int));
 103 STATIC int varisset __P((char *, int));
 104 STATIC void varvalue __P((char *, int, int));
 105 STATIC void recordregion __P((int, int, int));
 106 STATIC void removerecordregions __P((int));
 107 STATIC void ifsbreakup __P((char *, struct arglist *));
 108 STATIC void expandmeta __P((struct strlist *, int));
 109 STATIC void expmeta __P((char *, char *));
 110 STATIC void addfname __P((char *));
 111 STATIC struct strlist *expsort __P((struct strlist *));
 112 STATIC struct strlist *msort __P((struct strlist *, int));
 113 STATIC int pmatch __P((char *, char *));
 114 STATIC char *cvtnum __P((int, char *));
 115 STATIC int collate_range_cmp __P((int, int));
 116
 117 STATIC int collate_range_cmp (c1, c2)
 118         int c1, c2;
 119 {
 120         static char s1[2], s2[2];
 121         int ret;
 122
 123         c1 &= UCHAR_MAX;
 124         c2 &= UCHAR_MAX;
 125         if (c1 == c2)
 126                 return (0);
 127         s1[0] = c1;
 128         s2[0] = c2;
 129         if ((ret = strcoll(s1, s2)) != 0)
 130                 return (ret);
 131         return (c1 - c2);
 132 }
 133
 134 /*
 135  * Expand shell variables and backquotes inside a here document.
 136  */
 137
 138 void
 139 expandhere(arg, fd)
 140         union node *arg;        /* the document */
 141         int fd;                 /* where to write the expanded version */
 142         {
 143         herefd = fd;
 144         expandarg(arg, (struct arglist *)NULL, 0);
 145         xwrite(fd, stackblock(), expdest - stackblock());
 146 }
 147
 148
 149 /*
 150  * Perform variable substitution and command substitution on an argument,
 151  * placing the resulting list of arguments in arglist.  If EXP_FULL is true,
 152  * perform splitting and file name expansion.  When arglist is NULL, perform
 153  * here document expansion.
 154  */
 155
 156 void
 157 expandarg(arg, arglist, flag)
 158         union node *arg;
 159         struct arglist *arglist;
 160         int flag;
 161 {
 162         struct strlist *sp;
 163         char *p;
 164
 165         argbackq = arg->narg.backquote;
 166         STARTSTACKSTR(expdest);
 167         ifsfirst.next = NULL;
 168         ifslastp = NULL;
 169         argstr(arg->narg.text, flag);
 170         if (arglist == NULL) {
 171                 return;                 /* here document expanded */
 172         }
 173         STPUTC('\0', expdest);
 174         p = grabstackstr(expdest);
 175         exparg.lastp = &exparg.list;
 176         /*
 177          * TODO - EXP_REDIR
 178          */
 179         if (flag & EXP_FULL) {
 180                 ifsbreakup(p, &exparg);
 181                 *exparg.lastp = NULL;
 182                 exparg.lastp = &exparg.list;
 183                 expandmeta(exparg.list, flag);
 184         } else {
 185                 if (flag & EXP_REDIR) /*XXX - for now, just remove escapes */
 186                         rmescapes(p);
 187                 sp = (struct strlist *)stalloc(sizeof (struct strlist));
 188                 sp->text = p;
 189                 *exparg.lastp = sp;
 190                 exparg.lastp = &sp->next;
 191         }
 192         while (ifsfirst.next != NULL) {
 193                 struct ifsregion *ifsp;
 194                 INTOFF;
 195                 ifsp = ifsfirst.next->next;
 196                 ckfree(ifsfirst.next);
 197                 ifsfirst.next = ifsp;
 198                 INTON;
 199         }
 200         *exparg.lastp = NULL;
 201         if (exparg.list) {
 202                 *arglist->lastp = exparg.list;
 203                 arglist->lastp = exparg.lastp;
 204         }
 205 }
 206
 207
 208
 209 /*
 210  * Perform variable and command substitution.  If EXP_FULL is set, output CTLESC
 211  * characters to allow for further processing.  Otherwise treat
 212  * $@ like $* since no splitting will be performed.
 213  */
 214
 215 STATIC void
 216 argstr(p, flag)
 217         char *p;
 218         int flag;
 219 {
 220         char c;
 221         int quotes = flag & (EXP_FULL | EXP_CASE);      /* do CTLESC */
 222         int firsteq = 1;
 223
 224         if (*p == '~' && (flag & (EXP_TILDE | EXP_VARTILDE)))
 225                 p = exptilde(p, flag);
 226         for (;;) {
 227                 switch (c = *p++) {
 228                 case '\0':
 229                 case CTLENDVAR: /* ??? */
 230                         goto breakloop;
 231                 case CTLQUOTEMARK:
 232                         /* "$@" syntax adherence hack */
 233                         if (p[0] == CTLVAR && p[2] == '@' && p[3] == '=')
 234                                 break;
 235                         if ((flag & EXP_FULL) != 0)
 236                                 STPUTC(c, expdest);
 237                         break;
 238                 case CTLESC:
 239                         if (quotes)
 240                                 STPUTC(c, expdest);
 241                         c = *p++;
 242                         STPUTC(c, expdest);
 243                         break;
 244                 case CTLVAR:
 245                         p = evalvar(p, flag);
 246                         break;
 247                 case CTLBACKQ:
 248                 case CTLBACKQ|CTLQUOTE:
 249                         expbackq(argbackq->n, c & CTLQUOTE, flag);
 250                         argbackq = argbackq->next;
 251                         break;
 252                 case CTLENDARI:
 253                         expari(flag);
 254                         break;
 255                 case ':':
 256                 case '=':
 257                         /*
 258                          * sort of a hack - expand tildes in variable
 259                          * assignments (after the first '=' and after ':'s).
 260                          */
 261                         STPUTC(c, expdest);
 262                         if (flag & EXP_VARTILDE && *p == '~') {
 263                                 if (c == '=') {
 264                                         if (firsteq)
 265                                                 firsteq = 0;
 266                                         else
 267                                                 break;
 268                                 }
 269                                 p = exptilde(p, flag);
 270                         }
 271                         break;
 272                 default:
 273                         STPUTC(c, expdest);
 274                 }
 275         }
 276 breakloop:;
 277 }
 278
 279 STATIC char *
 280 exptilde(p, flag)
 281         char *p;
 282         int flag;
 283 {
 284         char c, *startp = p;
 285         struct passwd *pw;
 286         char *home;
 287         int quotes = flag & (EXP_FULL | EXP_CASE);
 288
 289         while ((c = *p) != '\0') {
 290                 switch(c) {
 291                 case CTLESC:
 292                         return (startp);
 293                 case CTLQUOTEMARK:
 294                         return (startp);
 295                 case ':':
 296                         if (flag & EXP_VARTILDE)
 297                                 goto done;
 298                         break;
 299                 case '/':
 300                         goto done;
 301                 }
 302                 p++;
 303         }
 304 done:
 305         *p = '\0';
 306         if (*(startp+1) == '\0') {
 307                 if ((home = lookupvar("HOME")) == NULL)
 308                         goto lose;
 309         } else {
 310                 if ((pw = getpwnam(startp+1)) == NULL)
 311                         goto lose;
 312                 home = pw->pw_dir;
 313         }
 314         if (*home == '\0')
 315                 goto lose;
 316         *p = c;
 317         while ((c = *home++) != '\0') {
 318                 if (quotes && SQSYNTAX[c] == CCTL)
 319                         STPUTC(CTLESC, expdest);
 320                 STPUTC(c, expdest);
 321         }
 322         return (p);
 323 lose:
 324         *p = c;
 325         return (startp);
 326 }
 327
 328
 329 STATIC void
 330 removerecordregions(endoff)
 331         int endoff;
 332 {
 333         if (ifslastp == NULL)
 334                 return;
 335
 336         if (ifsfirst.endoff > endoff) {
 337                 while (ifsfirst.next != NULL) {
 338                         struct ifsregion *ifsp;
 339                         INTOFF;
 340                         ifsp = ifsfirst.next->next;
 341                         ckfree(ifsfirst.next);
 342                         ifsfirst.next = ifsp;
 343                         INTON;
 344                 }
 345                 if (ifsfirst.begoff > endoff)
 346                         ifslastp = NULL;
 347                 else {
 348                         ifslastp = &ifsfirst;
 349                         ifsfirst.endoff = endoff;
 350                 }
 351                 return;
 352         }
 353
 354         ifslastp = &ifsfirst;
 355         while (ifslastp->next && ifslastp->next->begoff < endoff)
 356                 ifslastp=ifslastp->next;
 357         while (ifslastp->next != NULL) {
 358                 struct ifsregion *ifsp;
 359                 INTOFF;
 360                 ifsp = ifslastp->next->next;
 361                 ckfree(ifslastp->next);
 362                 ifslastp->next = ifsp;
 363                 INTON;
 364         }
 365         if (ifslastp->endoff > endoff)
 366                 ifslastp->endoff = endoff;
 367 }
 368
 369 /*
 370  * Expand arithmetic expression.  Backup to start of expression,
 371  * evaluate, place result in (backed up) result, adjust string position.
 372  */
 373 void
 374 expari(flag)
 375         int flag;
 376 {
 377         char *p, *start;
 378         int result;
 379         int begoff;
 380         int quotes = flag & (EXP_FULL | EXP_CASE);
 381         int quoted;
 382
 383
 384         /*
 385          * This routine is slightly over-compilcated for
 386          * efficiency.  First we make sure there is
 387          * enough space for the result, which may be bigger
 388          * than the expression if we add exponentation.  Next we
 389          * scan backwards looking for the start of arithmetic.  If the
 390          * next previous character is a CTLESC character, then we
 391          * have to rescan starting from the beginning since CTLESC
 392          * characters have to be processed left to right.
 393          */
 394 #if INT_MAX / 1000000000 >= 10 || INT_MIN / 1000000000 <= -10
 395 #error "integers with more than 10 digits are not supported"
 396 #endif
 397         CHECKSTRSPACE(12 - 2, expdest);
 398         USTPUTC('\0', expdest);
 399         start = stackblock();
 400         p = expdest;
 401         while (*p != CTLARI && p >= start)
 402                 --p;
 403         if (*p != CTLARI)
 404                 error("missing CTLARI (shouldn't happen)");
 405         if (p > start && *(p-1) == CTLESC)
 406                 for (p = start; *p != CTLARI; p++)
 407                         if (*p == CTLESC)
 408                                 p++;
 409
 410         if (p[1] == '"')
 411                 quoted=1;
 412         else
 413                 quoted=0;
 414         begoff = p - start;
 415         removerecordregions(begoff);
 416         if (quotes)
 417                 rmescapes(p+2);
 418         result = arith(p+2);
 419         fmtstr(p, 12, "%d", result);
 420         while (*p++)
 421                 ;
 422         if (quoted == 0)
 423                 recordregion(begoff, p - 1 - start, 0);
 424         result = expdest - p + 1;
 425         STADJUST(-result, expdest);
 426 }
 427
 428
 429 /*
 430  * Expand stuff in backwards quotes.
 431  */
 432
 433 STATIC void
 434 expbackq(cmd, quoted, flag)
 435         union node *cmd;
 436         int quoted;
 437         int flag;
 438 {
 439         struct backcmd in;
 440         int i;
 441         char buf[128];
 442         char *p;
 443         char *dest = expdest;
 444         struct ifsregion saveifs, *savelastp;
 445         struct nodelist *saveargbackq;
 446         char lastc;
 447         int startloc = dest - stackblock();
 448         char const *syntax = quoted? DQSYNTAX : BASESYNTAX;
 449         int saveherefd;
 450         int quotes = flag & (EXP_FULL | EXP_CASE);
 451
 452         INTOFF;
 453         saveifs = ifsfirst;
 454         savelastp = ifslastp;
 455         saveargbackq = argbackq;
 456         saveherefd = herefd;
 457         herefd = -1;
 458         p = grabstackstr(dest);
 459         evalbackcmd(cmd, &in);
 460         ungrabstackstr(p, dest);
 461         ifsfirst = saveifs;
 462         ifslastp = savelastp;
 463         argbackq = saveargbackq;
 464         herefd = saveherefd;
 465
 466         p = in.buf;
 467         lastc = '\0';
 468         for (;;) {
 469                 if (--in.nleft < 0) {
 470                         if (in.fd < 0)
 471                                 break;
 472                         while ((i = read(in.fd, buf, sizeof buf)) < 0 && errno == EINTR);
 473                         TRACE(("expbackq: read returns %d\n", i));
 474                         if (i <= 0)
 475                                 break;
 476                         p = buf;
 477                         in.nleft = i - 1;
 478                 }
 479                 lastc = *p++;
 480                 if (lastc != '\0') {
 481                         if (quotes && syntax[lastc] == CCTL)
 482                                 STPUTC(CTLESC, dest);
 483                         STPUTC(lastc, dest);
 484                 }
 485         }
 486
 487         /* Eat all trailing newlines */
 488         for (p--; lastc == '\n'; lastc = *--p)
 489                 STUNPUTC(dest);
 490
 491         if (in.fd >= 0)
 492                 close(in.fd);
 493         if (in.buf)
 494                 ckfree(in.buf);
 495         if (in.jp)
 496                 exitstatus = waitforjob(in.jp);
 497         if (quoted == 0)
 498                 recordregion(startloc, dest - stackblock(), 0);
 499         TRACE(("evalbackq: size=%d: \"%.*s\"\n",
 500                 (dest - stackblock()) - startloc,
 501                 (dest - stackblock()) - startloc,
 502                 stackblock() + startloc));
 503         expdest = dest;
 504         INTON;
 505 }
 506
 507
 508
 509 STATIC int
 510 subevalvar(p, str, strloc, subtype, startloc, varflags)
 511         char *p;
 512         char *str;
 513         int strloc;
 514         int subtype;
 515         int startloc;
 516         int varflags;
 517 {
 518         char *startp;
 519         char *loc = NULL;
 520         int c = 0;
 521         int saveherefd = herefd;
 522         struct nodelist *saveargbackq = argbackq;
 523         int amount;
 524
 525         herefd = -1;
 526         argstr(p, 0);
 527         STACKSTRNUL(expdest);
 528         herefd = saveherefd;
 529         argbackq = saveargbackq;
 530         startp = stackblock() + startloc;
 531         if (str == NULL)
 532             str = stackblock() + strloc;
 533
 534         switch (subtype) {
 535         case VSASSIGN:
 536                 setvar(str, startp, 0);
 537                 amount = startp - expdest;
 538                 STADJUST(amount, expdest);
 539                 varflags &= ~VSNUL;
 540                 if (c != 0)
 541                         *loc = c;
 542                 return 1;
 543
 544         case VSQUESTION:
 545                 if (*p != CTLENDVAR) {
 546                         outfmt(&errout, "%s\n", startp);
 547                         error((char *)NULL);
 548                 }
 549                 error("%.*s: parameter %snot set", p - str - 1,
 550                       str, (varflags & VSNUL) ? "null or "
 551                                               : nullstr);
 552                 return 0;
 553
 554         case VSTRIMLEFT:
 555                 for (loc = startp; loc < str; loc++) {
 556                         c = *loc;
 557                         *loc = '\0';
 558                         if (patmatch(str, startp)) {
 559                                 *loc = c;
 560                                 goto recordleft;
 561                         }
 562                         *loc = c;
 563                 }
 564                 return 0;
 565
 566         case VSTRIMLEFTMAX:
 567                 for (loc = str - 1; loc >= startp; loc--) {
 568                         c = *loc;
 569                         *loc = '\0';
 570                         if (patmatch(str, startp)) {
 571                                 *loc = c;
 572                                 goto recordleft;
 573                         }
 574                         *loc = c;
 575                 }
 576                 return 0;
 577
 578         case VSTRIMRIGHT:
 579                 for (loc = str - 1; loc >= startp; loc--) {
 580                         if (patmatch(str, loc)) {
 581                                 amount = loc - expdest;
 582                                 STADJUST(amount, expdest);
 583                                 return 1;
 584                         }
 585                 }
 586                 return 0;
 587
 588         case VSTRIMRIGHTMAX:
 589                 for (loc = startp; loc < str - 1; loc++) {
 590                         if (patmatch(str, loc)) {
 591                                 amount = loc - expdest;
 592                                 STADJUST(amount, expdest);
 593                                 return 1;
 594                         }
 595                 }
 596                 return 0;
 597
 598
 599         default:
 600                 abort();
 601         }
 602
 603 recordleft:
 604         amount = ((str - 1) - (loc - startp)) - expdest;
 605         STADJUST(amount, expdest);
 606         while (loc != str - 1)
 607                 *startp++ = *loc++;
 608         return 1;
 609 }
 610
 611
 612 /*
 613  * Expand a variable, and return a pointer to the next character in the
 614  * input string.
 615  */
 616
 617 STATIC char *
 618 evalvar(p, flag)
 619         char *p;
 620         int flag;
 621 {
 622         int subtype;
 623         int varflags;
 624         char *var;
 625         char *val;
 626         char *pat;
 627         int c;
 628         int set;
 629         int special;
 630         int startloc;
 631         int varlen;
 632         int easy;
 633         int quotes = flag & (EXP_FULL | EXP_CASE);
 634
 635         varflags = *p++;
 636         subtype = varflags & VSTYPE;
 637         var = p;
 638         special = 0;
 639         if (! is_name(*p))
 640                 special = 1;
 641         p = strchr(p, '=') + 1;
 642 again: /* jump here after setting a variable with ${var=text} */
 643         if (special) {
 644                 set = varisset(var, varflags & VSNUL);
 645                 val = NULL;
 646         } else {
 647                 val = lookupvar(var);
 648                 if (val == NULL || ((varflags & VSNUL) && val[0] == '\0')) {
 649                         val = NULL;
 650                         set = 0;
 651                 } else
 652                         set = 1;
 653         }
 654         varlen = 0;
 655         startloc = expdest - stackblock();
 656         if (set && subtype != VSPLUS) {
 657                 /* insert the value of the variable */
 658                 if (special) {
 659                         varvalue(var, varflags & VSQUOTE, flag & EXP_FULL);
 660                         if (subtype == VSLENGTH) {
 661                                 varlen = expdest - stackblock() - startloc;
 662                                 STADJUST(-varlen, expdest);
 663                         }
 664                 } else {
 665                         char const *syntax = (varflags & VSQUOTE) ? DQSYNTAX
 666                                                                   : BASESYNTAX;
 667
 668                         if (subtype == VSLENGTH) {
 669                                 for (;*val; val++)
 670                                         varlen++;
 671                         }
 672                         else {
 673                                 while (*val) {
 674                                         if (quotes && syntax[*val] == CCTL)
 675                                                 STPUTC(CTLESC, expdest);
 676                                         STPUTC(*val++, expdest);
 677                                 }
 678
 679                         }
 680                 }
 681         }
 682
 683         if (subtype == VSPLUS)
 684                 set = ! set;
 685
 686         easy = ((varflags & VSQUOTE) == 0 ||
 687                 (*var == '@' && shellparam.nparam != 1));
 688
 689
 690         switch (subtype) {
 691         case VSLENGTH:
 692                 expdest = cvtnum(varlen, expdest);
 693                 goto record;
 694
 695         case VSNORMAL:
 696                 if (!easy)
 697                         break;
 698 record:
 699                 recordregion(startloc, expdest - stackblock(),
 700                              varflags & VSQUOTE);
 701                 break;
 702
 703         case VSPLUS:
 704         case VSMINUS:
 705                 if (!set) {
 706                         argstr(p, flag);
 707                         break;
 708                 }
 709                 if (easy)
 710                         goto record;
 711                 break;
 712
 713         case VSTRIMLEFT:
 714         case VSTRIMLEFTMAX:
 715         case VSTRIMRIGHT:
 716         case VSTRIMRIGHTMAX:
 717                 if (!set)
 718                         break;
 719                 /*
 720                  * Terminate the string and start recording the pattern
 721                  * right after it
 722                  */
 723                 STPUTC('\0', expdest);
 724                 pat = expdest;
 725                 if (subevalvar(p, NULL, expdest - stackblock(), subtype,
 726                                startloc, varflags) == 0) {
 727                         int amount = (expdest - pat) + 1;
 728                         STADJUST(-amount, expdest);
 729                 }
 730                 /* Remove any recorded regions beyond start of variable */
 731                 removerecordregions(startloc);
 732                 goto record;
 733
 734         case VSASSIGN:
 735         case VSQUESTION:
 736                 if (!set) {
 737                         if (subevalvar(p, var, 0, subtype, startloc, varflags)) {
 738                                 varflags &= ~VSNUL;
 739                                 /*
 740                                  * Remove any recorded regions beyond
 741                                  * start of variable
 742                                  */
 743                                 removerecordregions(startloc);
 744                                 goto again;
 745                         }
 746                         break;
 747                 }
 748                 if (easy)
 749                         goto record;
 750                 break;
 751
 752         default:
 753                 abort();
 754         }
 755
 756         if (subtype != VSNORMAL) {      /* skip to end of alternative */
 757                 int nesting = 1;
 758                 for (;;) {
 759                         if ((c = *p++) == CTLESC)
 760                                 p++;
 761                         else if (c == CTLBACKQ || c == (CTLBACKQ|CTLQUOTE)) {
 762                                 if (set)
 763                                         argbackq = argbackq->next;
 764                         } else if (c == CTLVAR) {
 765                                 if ((*p++ & VSTYPE) != VSNORMAL)
 766                                         nesting++;
 767                         } else if (c == CTLENDVAR) {
 768                                 if (--nesting == 0)
 769                                         break;
 770                         }
 771                 }
 772         }
 773         return p;
 774 }
 775
 776
 777
 778 /*
 779  * Test whether a specialized variable is set.
 780  */
 781
 782 STATIC int
 783 varisset(name, nulok)
 784         char *name;
 785         int nulok;
 786 {
 787
 788         if (*name == '!')
 789                 return backgndpid != -1;
 790         else if (*name == '@' || *name == '*') {
 791                 if (*shellparam.p == NULL)
 792                         return 0;
 793
 794                 if (nulok) {
 795                         char **av;
 796
 797                         for (av = shellparam.p; *av; av++)
 798                                 if (**av != '\0')
 799                                         return 1;
 800                         return 0;
 801                 }
 802         } else if (is_digit(*name)) {
 803                 char *ap;
 804                 int num = atoi(name);
 805
 806                 if (num > shellparam.nparam)
 807                         return 0;
 808
 809                 if (num == 0)
 810                         ap = arg0;
 811                 else
 812                         ap = shellparam.p[num - 1];
 813
 814                 if (nulok && (ap == NULL || *ap == '\0'))
 815                         return 0;
 816         }
 817         return 1;
 818 }
 819
 820
 821
 822 /*
 823  * Add the value of a specialized variable to the stack string.
 824  */
 825
 826 STATIC void
 827 varvalue(name, quoted, allow_split)
 828         char *name;
 829         int quoted;
 830         int allow_split;
 831 {
 832         int num;
 833         char *p;
 834         int i;
 835         extern int oexitstatus;
 836         char sep;
 837         char **ap;
 838         char const *syntax;
 839
 840 #define STRTODEST(p) \
 841         do {\
 842         if (allow_split) { \
 843                 syntax = quoted? DQSYNTAX : BASESYNTAX; \
 844                 while (*p) { \
 845                         if (syntax[*p] == CCTL) \
 846                                 STPUTC(CTLESC, expdest); \
 847                         STPUTC(*p++, expdest); \
 848                 } \
 849         } else \
 850                 while (*p) \
 851                         STPUTC(*p++, expdest); \
 852         } while (0)
 853
 854
 855         switch (*name) {
 856         case '$':
 857                 num = rootpid;
 858                 goto numvar;
 859         case '?':
 860                 num = oexitstatus;
 861                 goto numvar;
 862         case '#':
 863                 num = shellparam.nparam;
 864                 goto numvar;
 865         case '!':
 866                 num = backgndpid;
 867 numvar:
 868                 expdest = cvtnum(num, expdest);
 869                 break;
 870         case '-':
 871                 for (i = 0 ; i < NOPTS ; i++) {
 872                         if (optlist[i].val)
 873                                 STPUTC(optlist[i].letter, expdest);
 874                 }
 875                 break;
 876         case '@':
 877                 if (allow_split && quoted) {
 878                         for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
 879                                 STRTODEST(p);
 880                                 if (*ap)
 881                                         STPUTC('\0', expdest);
 882                         }
 883                         break;
 884                 }
 885                 /* fall through */
 886         case '*':
 887                 if (ifsset() != 0)
 888                         sep = ifsval()[0];
 889                 else
 890                         sep = ' ';
 891                 for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
 892                         STRTODEST(p);
 893                         if (*ap && sep)
 894                                 STPUTC(sep, expdest);
 895                 }
 896                 break;
 897         case '0':
 898                 p = arg0;
 899                 STRTODEST(p);
 900                 break;
 901         default:
 902                 if (is_digit(*name)) {
 903                         num = atoi(name);
 904                         if (num > 0 && num <= shellparam.nparam) {
 905                                 p = shellparam.p[num - 1];
 906                                 STRTODEST(p);
 907                         }
 908                 }
 909                 break;
 910         }
 911 }
 912
 913
 914
 915 /*
 916  * Record the the fact that we have to scan this region of the
 917  * string for IFS characters.
 918  */
 919
 920 STATIC void
 921 recordregion(start, end, nulonly)
 922         int start;
 923         int end;
 924         int nulonly;
 925 {
 926         struct ifsregion *ifsp;
 927
 928         if (ifslastp == NULL) {
 929                 ifsp = &ifsfirst;
 930         } else {
 931                 ifsp = (struct ifsregion *)ckmalloc(sizeof (struct ifsregion));
 932                 ifslastp->next = ifsp;
 933         }
 934         ifslastp = ifsp;
 935         ifslastp->next = NULL;
 936         ifslastp->begoff = start;
 937         ifslastp->endoff = end;
 938         ifslastp->nulonly = nulonly;
 939 }
 940
 941
 942
 943 /*
 944  * Break the argument string into pieces based upon IFS and add the
 945  * strings to the argument list.  The regions of the string to be
 946  * searched for IFS characters have been stored by recordregion.
 947  */
 948 STATIC void
 949 ifsbreakup(string, arglist)
 950         char *string;
 951         struct arglist *arglist;
 952         {
 953         struct ifsregion *ifsp;
 954         struct strlist *sp;
 955         char *start;
 956         char *p;
 957         char *q;
 958         char *ifs;
 959         int ifsspc;
 960         int nulonly;
 961
 962
 963         start = string;
 964         ifsspc = 0;
 965         nulonly = 0;
 966         if (ifslastp != NULL) {
 967                 ifsp = &ifsfirst;
 968                 do {
 969                         p = string + ifsp->begoff;
 970                         nulonly = ifsp->nulonly;
 971                         ifs = nulonly ? nullstr :
 972                                 ( ifsset() ? ifsval() : " \t\n" );
 973                         ifsspc = 0;
 974                         while (p < string + ifsp->endoff) {
 975                                 q = p;
 976                                 if (*p == CTLESC)
 977                                         p++;
 978                                 if (strchr(ifs, *p)) {
 979                                         if (!nulonly)
 980                                                 ifsspc = (strchr(" \t\n", *p) != NULL);
 981                                         /* Ignore IFS whitespace at start */
 982                                         if (q == start && ifsspc) {
 983                                                 p++;
 984                                                 start = p;
 985                                                 continue;
 986                                         }
 987                                         *q = '\0';
 988                                         sp = (struct strlist *)stalloc(sizeof *sp);
 989                                         sp->text = start;
 990                                         *arglist->lastp = sp;
 991                                         arglist->lastp = &sp->next;
 992                                         p++;
 993                                         if (!nulonly) {
 994                                                 for (;;) {
 995                                                         if (p >= string + ifsp->endoff) {
 996                                                                 break;
 997                                                         }
 998                                                         q = p;
 999                                                         if (*p == CTLESC)
1000                                                                 p++;
1001                                                         if (strchr(ifs, *p) == NULL ) {
1002                                                                 p = q;
1003                                                                 break;
1004                                                         } else if (strchr(" \t\n",*p) == NULL) {
1005                                                                 if (ifsspc) {
1006                                                                         p++;
1007                                                                         ifsspc = 0;
1008                                                                 } else {
1009                                                                         p = q;
1010                                                                         break;
1011                                                                 }
1012                                                         } else
1013                                                                 p++;
1014                                                 }
1015                                         }
1016                                         start = p;
1017                                 } else
1018                                         p++;
1019                         }
1020                 } while ((ifsp = ifsp->next) != NULL);
1021                 if (*start || (!ifsspc && start > string &&
1022                         (nulonly || 1))) {
1023                         sp = (struct strlist *)stalloc(sizeof *sp);
1024                         sp->text = start;
1025                         *arglist->lastp = sp;
1026                         arglist->lastp = &sp->next;
1027                 }
1028         } else {
1029                 sp = (struct strlist *)stalloc(sizeof *sp);
1030                 sp->text = start;
1031                 *arglist->lastp = sp;
1032                 arglist->lastp = &sp->next;
1033         }
1034 }
1035
1036
1037
1038 /*
1039  * Expand shell metacharacters.  At this point, the only control characters
1040  * should be escapes.  The results are stored in the list exparg.
1041  */
1042
1043 char *expdir;
1044
1045
1046 STATIC void
1047 expandmeta(str, flag)
1048         struct strlist *str;
1049         int flag __unused;
1050 {
1051         char *p;
1052         struct strlist **savelastp;
1053         struct strlist *sp;
1054         char c;
1055         /* TODO - EXP_REDIR */
1056
1057         while (str) {
1058                 if (fflag)
1059                         goto nometa;
1060                 p = str->text;
1061                 for (;;) {                      /* fast check for meta chars */
1062                         if ((c = *p++) == '\0')
1063                                 goto nometa;
1064                         if (c == '*' || c == '?' || c == '[' || c == '!')
1065                                 break;
1066                 }
1067                 savelastp = exparg.lastp;
1068                 INTOFF;
1069                 if (expdir == NULL) {
1070                         int i = strlen(str->text);
1071                         expdir = ckmalloc(i < 2048 ? 2048 : i); /* XXX */
1072                 }
1073
1074                 expmeta(expdir, str->text);
1075                 ckfree(expdir);
1076                 expdir = NULL;
1077                 INTON;
1078                 if (exparg.lastp == savelastp) {
1079                         /*
1080                          * no matches
1081                          */
1082 nometa:
1083                         *exparg.lastp = str;
1084                         rmescapes(str->text);
1085                         exparg.lastp = &str->next;
1086                 } else {
1087                         *exparg.lastp = NULL;
1088                         *savelastp = sp = expsort(*savelastp);
1089                         while (sp->next != NULL)
1090                                 sp = sp->next;
1091                         exparg.lastp = &sp->next;
1092                 }
1093                 str = str->next;
1094         }
1095 }
1096
1097
1098 /*
1099  * Do metacharacter (i.e. *, ?, [...]) expansion.
1100  */
1101
1102 STATIC void
1103 expmeta(enddir, name)
1104         char *enddir;
1105         char *name;
1106         {
1107         char *p;
1108         char *q;
1109         char *start;
1110         char *endname;
1111         int metaflag;
1112         struct stat statb;
1113         DIR *dirp;
1114         struct dirent *dp;
1115         int atend;
1116         int matchdot;
1117
1118         metaflag = 0;
1119         start = name;
1120         for (p = name ; ; p++) {
1121                 if (*p == '*' || *p == '?')
1122                         metaflag = 1;
1123                 else if (*p == '[') {
1124                         q = p + 1;
1125                         if (*q == '!' || *q == '^')
1126                                 q++;
1127                         for (;;) {
1128                                 while (*q == CTLQUOTEMARK)
1129                                         q++;
1130                                 if (*q == CTLESC)
1131                                         q++;
1132                                 if (*q == '/' || *q == '\0')
1133                                         break;
1134                                 if (*++q == ']') {
1135                                         metaflag = 1;
1136                                         break;
1137                                 }
1138                         }
1139                 } else if (*p == '!' && p[1] == '!'     && (p == name || p[-1] == '/')) {
1140                         metaflag = 1;
1141                 } else if (*p == '\0')
1142                         break;
1143                 else if (*p == CTLQUOTEMARK)
1144                         continue;
1145                 else if (*p == CTLESC)
1146                         p++;
1147                 if (*p == '/') {
1148                         if (metaflag)
1149                                 break;
1150                         start = p + 1;
1151                 }
1152         }
1153         if (metaflag == 0) {    /* we've reached the end of the file name */
1154                 if (enddir != expdir)
1155                         metaflag++;
1156                 for (p = name ; ; p++) {
1157                         if (*p == CTLQUOTEMARK)
1158                                 continue;
1159                         if (*p == CTLESC)
1160                                 p++;
1161                         *enddir++ = *p;
1162                         if (*p == '\0')
1163                                 break;
1164                 }
1165                 if (metaflag == 0 || stat(expdir, &statb) >= 0)
1166                         addfname(expdir);
1167                 return;
1168         }
1169         endname = p;
1170         if (start != name) {
1171                 p = name;
1172                 while (p < start) {
1173                         while (*p == CTLQUOTEMARK)
1174                                 p++;
1175                         if (*p == CTLESC)
1176                                 p++;
1177                         *enddir++ = *p++;
1178                 }
1179         }
1180         if (enddir == expdir) {
1181                 p = ".";
1182         } else if (enddir == expdir + 1 && *expdir == '/') {
1183                 p = "/";
1184         } else {
1185                 p = expdir;
1186                 enddir[-1] = '\0';
1187         }
1188         if ((dirp = opendir(p)) == NULL)
1189                 return;
1190         if (enddir != expdir)
1191                 enddir[-1] = '/';
1192         if (*endname == 0) {
1193                 atend = 1;
1194         } else {
1195                 atend = 0;
1196                 *endname++ = '\0';
1197         }
1198         matchdot = 0;
1199         p = start;
1200         while (*p == CTLQUOTEMARK)
1201                 p++;
1202         if (*p == CTLESC)
1203                 p++;
1204         if (*p == '.')
1205                 matchdot++;
1206         while (! int_pending() && (dp = readdir(dirp)) != NULL) {
1207                 if (dp->d_name[0] == '.' && ! matchdot)
1208                         continue;
1209                 if (patmatch(start, dp->d_name)) {
1210                         if (atend) {
1211                                 scopy(dp->d_name, enddir);
1212                                 addfname(expdir);
1213                         } else {
1214                                 char *q;
1215                                 for (p = enddir, q = dp->d_name;
1216                                      (*p++ = *q++) != '\0';)
1217                                         continue;
1218                                 p[-1] = '/';
1219                                 expmeta(p, endname);
1220                         }
1221                 }
1222         }
1223         closedir(dirp);
1224         if (! atend)
1225                 endname[-1] = '/';
1226 }
1227
1228
1229 /*
1230  * Add a file name to the list.
1231  */
1232
1233 STATIC void
1234 addfname(name)
1235         char *name;
1236         {
1237         char *p;
1238         struct strlist *sp;
1239
1240         p = stalloc(strlen(name) + 1);
1241         scopy(name, p);
1242         sp = (struct strlist *)stalloc(sizeof *sp);
1243         sp->text = p;
1244         *exparg.lastp = sp;
1245         exparg.lastp = &sp->next;
1246 }
1247
1248
1249 /*
1250  * Sort the results of file name expansion.  It calculates the number of
1251  * strings to sort and then calls msort (short for merge sort) to do the
1252  * work.
1253  */
1254
1255 STATIC struct strlist *
1256 expsort(str)
1257         struct strlist *str;
1258         {
1259         int len;
1260         struct strlist *sp;
1261
1262         len = 0;
1263         for (sp = str ; sp ; sp = sp->next)
1264                 len++;
1265         return msort(str, len);
1266 }
1267
1268
1269 STATIC struct strlist *
1270 msort(list, len)
1271         struct strlist *list;
1272         int len;
1273 {
1274         struct strlist *p, *q = NULL;
1275         struct strlist **lpp;
1276         int half;
1277         int n;
1278
1279         if (len <= 1)
1280                 return list;
1281         half = len >> 1;
1282         p = list;
1283         for (n = half ; --n >= 0 ; ) {
1284                 q = p;
1285                 p = p->next;
1286         }
1287         q->next = NULL;                 /* terminate first half of list */
1288         q = msort(list, half);          /* sort first half of list */
1289         p = msort(p, len - half);               /* sort second half */
1290         lpp = &list;
1291         for (;;) {
1292                 if (strcmp(p->text, q->text) < 0) {
1293                         *lpp = p;
1294                         lpp = &p->next;
1295                         if ((p = *lpp) == NULL) {
1296                                 *lpp = q;
1297                                 break;
1298                         }
1299                 } else {
1300                         *lpp = q;
1301                         lpp = &q->next;
1302                         if ((q = *lpp) == NULL) {
1303                                 *lpp = p;
1304                                 break;
1305                         }
1306                 }
1307         }
1308         return list;
1309 }
1310
1311
1312
1313 /*
1314  * Returns true if the pattern matches the string.
1315  */
1316
1317 int
1318 patmatch(pattern, string)
1319         char *pattern;
1320         char *string;
1321         {
1322 #ifdef notdef
1323         if (pattern[0] == '!' && pattern[1] == '!')
1324                 return 1 - pmatch(pattern + 2, string);
1325         else
1326 #endif
1327                 return pmatch(pattern, string);
1328 }
1329
1330
1331 STATIC int
1332 pmatch(pattern, string)
1333         char *pattern;
1334         char *string;
1335         {
1336         char *p, *q;
1337         char c;
1338
1339         p = pattern;
1340         q = string;
1341         for (;;) {
1342                 switch (c = *p++) {
1343                 case '\0':
1344                         goto breakloop;
1345                 case CTLESC:
1346                         if (*q++ != *p++)
1347                                 return 0;
1348                         break;
1349                 case CTLQUOTEMARK:
1350                         continue;
1351                 case '?':
1352                         if (*q++ == '\0')
1353                                 return 0;
1354                         break;
1355                 case '*':
1356                         c = *p;
1357                         while (c == CTLQUOTEMARK || c == '*')
1358                                 c = *++p;
1359                         if (c != CTLESC &&  c != CTLQUOTEMARK &&
1360                             c != '?' && c != '*' && c != '[') {
1361                                 while (*q != c) {
1362                                         if (*q == '\0')
1363                                                 return 0;
1364                                         q++;
1365                                 }
1366                         }
1367                         do {
1368                                 if (pmatch(p, q))
1369                                         return 1;
1370                         } while (*q++ != '\0');
1371                         return 0;
1372                 case '[': {
1373                         char *endp;
1374                         int invert, found;
1375                         char chr;
1376
1377                         endp = p;
1378                         if (*endp == '!' || *endp == '^')
1379                                 endp++;
1380                         for (;;) {
1381                                 while (*endp == CTLQUOTEMARK)
1382                                         endp++;
1383                                 if (*endp == '\0')
1384                                         goto dft;               /* no matching ] */
1385                                 if (*endp == CTLESC)
1386                                         endp++;
1387                                 if (*++endp == ']')
1388                                         break;
1389                         }
1390                         invert = 0;
1391                         if (*p == '!' || *p == '^') {
1392                                 invert++;
1393                                 p++;
1394                         }
1395                         found = 0;
1396                         chr = *q++;
1397                         if (chr == '\0')
1398                                 return 0;
1399                         c = *p++;
1400                         do {
1401                                 if (c == CTLQUOTEMARK)
1402                                         continue;
1403                                 if (c == CTLESC)
1404                                         c = *p++;
1405                                 if (*p == '-' && p[1] != ']') {
1406                                         p++;
1407                                         while (*p == CTLQUOTEMARK)
1408                                                 p++;
1409                                         if (*p == CTLESC)
1410                                                 p++;
1411                                         if (   collate_range_cmp(chr, c) >= 0
1412                                             && collate_range_cmp(chr, *p) <= 0
1413                                            )
1414                                                 found = 1;
1415                                         p++;
1416                                 } else {
1417                                         if (chr == c)
1418                                                 found = 1;
1419                                 }
1420                         } while ((c = *p++) != ']');
1421                         if (found == invert)
1422                                 return 0;
1423                         break;
1424                 }
1425 dft:            default:
1426                         if (*q++ != c)
1427                                 return 0;
1428                         break;
1429                 }
1430         }
1431 breakloop:
1432         if (*q != '\0')
1433                 return 0;
1434         return 1;
1435 }
1436
1437
1438
1439 /*
1440  * Remove any CTLESC characters from a string.
1441  */
1442
1443 void
1444 rmescapes(str)
1445         char *str;
1446 {
1447         char *p, *q;
1448
1449         p = str;
1450         while (*p != CTLESC && *p != CTLQUOTEMARK) {
1451                 if (*p++ == '\0')
1452                         return;
1453         }
1454         q = p;
1455         while (*p) {
1456                 if (*p == CTLQUOTEMARK) {
1457                         p++;
1458                         continue;
1459                 }
1460                 if (*p == CTLESC)
1461                         p++;
1462                 *q++ = *p++;
1463         }
1464         *q = '\0';
1465 }
1466
1467
1468
1469 /*
1470  * See if a pattern matches in a case statement.
1471  */
1472
1473 int
1474 casematch(pattern, val)
1475         union node *pattern;
1476         char *val;
1477         {
1478         struct stackmark smark;
1479         int result;
1480         char *p;
1481
1482         setstackmark(&smark);
1483         argbackq = pattern->narg.backquote;
1484         STARTSTACKSTR(expdest);
1485         ifslastp = NULL;
1486         argstr(pattern->narg.text, EXP_TILDE | EXP_CASE);
1487         STPUTC('\0', expdest);
1488         p = grabstackstr(expdest);
1489         result = patmatch(p, val);
1490         popstackmark(&smark);
1491         return result;
1492 }
1493
1494 /*
1495  * Our own itoa().
1496  */
1497
1498 STATIC char *
1499 cvtnum(num, buf)
1500         int num;
1501         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 }