bin/sh/expand.c

   1 /*-
   2  * Copyright (c) 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Kenneth Almquist.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * @(#)expand.c 8.5 (Berkeley) 5/15/95
  37  * $FreeBSD: src/bin/sh/expand.c,v 1.31.2.5 2003/01/17 07:44:01 tjr Exp $
  38  * $DragonFly: src/bin/sh/expand.c,v 1.7 2006/09/28 22:29:44 pavalos Exp $
  39  */
  40
  41 #include <sys/types.h>
  42 #include <sys/time.h>
  43 #include <sys/stat.h>
  44 #include <errno.h>
  45 #include <dirent.h>
  46 #include <unistd.h>
  47 #include <pwd.h>
  48 #include <stdlib.h>
  49 #include <limits.h>
  50 #include <stdio.h>
  51
  52 /*
  53  * Routines to expand arguments to commands.  We have to deal with
  54  * backquotes, shell variables, and file metacharacters.
  55  */
  56
  57 #include "shell.h"
  58 #include "main.h"
  59 #include "nodes.h"
  60 #include "eval.h"
  61 #include "expand.h"
  62 #include "syntax.h"
  63 #include "parser.h"
  64 #include "jobs.h"
  65 #include "options.h"
  66 #include "var.h"
  67 #include "input.h"
  68 #include "output.h"
  69 #include "memalloc.h"
  70 #include "error.h"
  71 #include "mystring.h"
  72 #include "arith.h"
  73 #include "show.h"
  74
  75 /*
  76  * Structure specifying which parts of the string should be searched
  77  * for IFS characters.
  78  */
  79
  80 struct ifsregion {
  81         struct ifsregion *next; /* next region in list */
  82         int begoff;             /* offset of start of region */
  83         int endoff;             /* offset of end of region */
  84         int nulonly;            /* search for nul bytes only */
  85 };
  86
  87
  88 STATIC char *expdest;                   /* output of current string */
  89 STATIC struct nodelist *argbackq;       /* list of back quote expressions */
  90 STATIC struct ifsregion ifsfirst;       /* first struct in list of ifs regions */
  91 STATIC struct ifsregion *ifslastp;      /* last struct in list */
  92 STATIC struct arglist exparg;           /* holds expanded arg list */
  93
  94 STATIC void argstr(char *, int);
  95 STATIC char *exptilde(char *, int);
  96 STATIC void expbackq(union node *, int, int);
  97 STATIC int subevalvar(char *, char *, int, int, int, int);
  98 STATIC char *evalvar(char *, int);
  99 STATIC int varisset(char *, int);
 100 STATIC void varvalue(char *, int, int);
 101 STATIC void recordregion(int, int, int);
 102 STATIC void removerecordregions(int);
 103 STATIC void ifsbreakup(char *, struct arglist *);
 104 STATIC void expandmeta(struct strlist *, int);
 105 STATIC void expmeta(char *, char *);
 106 STATIC void addfname(char *);
 107 STATIC struct strlist *expsort(struct strlist *);
 108 STATIC struct strlist *msort(struct strlist *, int);
 109 STATIC int pmatch(char *, char *, int);
 110 STATIC char *cvtnum(int, char *);
 111 STATIC int collate_range_cmp(int, int);
 112
 113 STATIC int
 114 collate_range_cmp (int c1, int c2)
 115 {
 116         static char s1[2], s2[2];
 117         int ret;
 118
 119         c1 &= UCHAR_MAX;
 120         c2 &= UCHAR_MAX;
 121         if (c1 == c2)
 122                 return (0);
 123         s1[0] = c1;
 124         s2[0] = c2;
 125         if ((ret = strcoll(s1, s2)) != 0)
 126                 return (ret);
 127         return (c1 - c2);
 128 }
 129
 130 extern int oexitstatus;
 131
 132 /*
 133  * Expand shell variables and backquotes inside a here document.
 134  *      union node *arg         the document
 135  *      int fd;                 where to write the expanded version
 136  */
 137
 138 void
 139 expandhere(union node *arg, int fd)
 140 {
 141         herefd = fd;
 142         expandarg(arg, (struct arglist *)NULL, 0);
 143         xwrite(fd, stackblock(), expdest - stackblock());
 144 }
 145
 146
 147 /*
 148  * Perform variable substitution and command substitution on an argument,
 149  * placing the resulting list of arguments in arglist.  If EXP_FULL is true,
 150  * perform splitting and file name expansion.  When arglist is NULL, perform
 151  * here document expansion.
 152  */
 153
 154 void
 155 expandarg(union node *arg, struct arglist *arglist, int flag)
 156 {
 157         struct strlist *sp;
 158         char *p;
 159
 160         argbackq = arg->narg.backquote;
 161         STARTSTACKSTR(expdest);
 162         ifsfirst.next = NULL;
 163         ifslastp = NULL;
 164         argstr(arg->narg.text, flag);
 165         if (arglist == NULL) {
 166                 return;                 /* here document expanded */
 167         }
 168         STPUTC('\0', expdest);
 169         p = grabstackstr(expdest);
 170         exparg.lastp = &exparg.list;
 171         /*
 172          * TODO - EXP_REDIR
 173          */
 174         if (flag & EXP_FULL) {
 175                 ifsbreakup(p, &exparg);
 176                 *exparg.lastp = NULL;
 177                 exparg.lastp = &exparg.list;
 178                 expandmeta(exparg.list, flag);
 179         } else {
 180                 if (flag & EXP_REDIR) /*XXX - for now, just remove escapes */
 181                         rmescapes(p);
 182                 sp = (struct strlist *)stalloc(sizeof (struct strlist));
 183                 sp->text = p;
 184                 *exparg.lastp = sp;
 185                 exparg.lastp = &sp->next;
 186         }
 187         while (ifsfirst.next != NULL) {
 188                 struct ifsregion *ifsp;
 189                 INTOFF;
 190                 ifsp = ifsfirst.next->next;
 191                 ckfree(ifsfirst.next);
 192                 ifsfirst.next = ifsp;
 193                 INTON;
 194         }
 195         *exparg.lastp = NULL;
 196         if (exparg.list) {
 197                 *arglist->lastp = exparg.list;
 198                 arglist->lastp = exparg.lastp;
 199         }
 200 }
 201
 202
 203
 204 /*
 205  * Perform variable and command substitution.  If EXP_FULL is set, output CTLESC
 206  * characters to allow for further processing.  Otherwise treat
 207  * $@ like $* since no splitting will be performed.
 208  */
 209
 210 STATIC void
 211 argstr(char *p, int flag)
 212 {
 213         char c;
 214         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);  /* do CTLESC */
 215         int firsteq = 1;
 216
 217         if (*p == '~' && (flag & (EXP_TILDE | EXP_VARTILDE)))
 218                 p = exptilde(p, flag);
 219         for (;;) {
 220                 switch (c = *p++) {
 221                 case '\0':
 222                 case CTLENDVAR: /* ??? */
 223                         goto breakloop;
 224                 case CTLQUOTEMARK:
 225                         /* "$@" syntax adherence hack */
 226                         if (p[0] == CTLVAR && p[2] == '@' && p[3] == '=')
 227                                 break;
 228                         if ((flag & EXP_FULL) != 0)
 229                                 STPUTC(c, expdest);
 230                         break;
 231                 case CTLESC:
 232                         if (quotes)
 233                                 STPUTC(c, expdest);
 234                         c = *p++;
 235                         STPUTC(c, expdest);
 236                         break;
 237                 case CTLVAR:
 238                         p = evalvar(p, flag);
 239                         break;
 240                 case CTLBACKQ:
 241                 case CTLBACKQ|CTLQUOTE:
 242                         expbackq(argbackq->n, c & CTLQUOTE, flag);
 243                         argbackq = argbackq->next;
 244                         break;
 245                 case CTLENDARI:
 246                         expari(flag);
 247                         break;
 248                 case ':':
 249                 case '=':
 250                         /*
 251                          * sort of a hack - expand tildes in variable
 252                          * assignments (after the first '=' and after ':'s).
 253                          */
 254                         STPUTC(c, expdest);
 255                         if (flag & EXP_VARTILDE && *p == '~') {
 256                                 if (c == '=') {
 257                                         if (firsteq)
 258                                                 firsteq = 0;
 259                                         else
 260                                                 break;
 261                                 }
 262                                 p = exptilde(p, flag);
 263                         }
 264                         break;
 265                 default:
 266                         STPUTC(c, expdest);
 267                 }
 268         }
 269 breakloop:;
 270 }
 271
 272 STATIC char *
 273 exptilde(char *p, int flag)
 274 {
 275         char c, *startp = p;
 276         struct passwd *pw;
 277         char *home;
 278         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 279
 280         while ((c = *p) != '\0') {
 281                 switch(c) {
 282                 case CTLESC:
 283                         return (startp);
 284                 case CTLQUOTEMARK:
 285                         return (startp);
 286                 case ':':
 287                         if (flag & EXP_VARTILDE)
 288                                 goto done;
 289                         break;
 290                 case '/':
 291                         goto done;
 292                 }
 293                 p++;
 294         }
 295 done:
 296         *p = '\0';
 297         if (*(startp+1) == '\0') {
 298                 if ((home = lookupvar("HOME")) == NULL)
 299                         goto lose;
 300         } else {
 301                 if ((pw = getpwnam(startp+1)) == NULL)
 302                         goto lose;
 303                 home = pw->pw_dir;
 304         }
 305         if (*home == '\0')
 306                 goto lose;
 307         *p = c;
 308         while ((c = *home++) != '\0') {
 309                 if (quotes && SQSYNTAX[(int)c] == CCTL)
 310                         STPUTC(CTLESC, expdest);
 311                 STPUTC(c, expdest);
 312         }
 313         return (p);
 314 lose:
 315         *p = c;
 316         return (startp);
 317 }
 318
 319
 320 STATIC void
 321 removerecordregions(int endoff)
 322 {
 323         if (ifslastp == NULL)
 324                 return;
 325
 326         if (ifsfirst.endoff > endoff) {
 327                 while (ifsfirst.next != NULL) {
 328                         struct ifsregion *ifsp;
 329                         INTOFF;
 330                         ifsp = ifsfirst.next->next;
 331                         ckfree(ifsfirst.next);
 332                         ifsfirst.next = ifsp;
 333                         INTON;
 334                 }
 335                 if (ifsfirst.begoff > endoff)
 336                         ifslastp = NULL;
 337                 else {
 338                         ifslastp = &ifsfirst;
 339                         ifsfirst.endoff = endoff;
 340                 }
 341                 return;
 342         }
 343
 344         ifslastp = &ifsfirst;
 345         while (ifslastp->next && ifslastp->next->begoff < endoff)
 346                 ifslastp=ifslastp->next;
 347         while (ifslastp->next != NULL) {
 348                 struct ifsregion *ifsp;
 349                 INTOFF;
 350                 ifsp = ifslastp->next->next;
 351                 ckfree(ifslastp->next);
 352                 ifslastp->next = ifsp;
 353                 INTON;
 354         }
 355         if (ifslastp->endoff > endoff)
 356                 ifslastp->endoff = endoff;
 357 }
 358
 359 /*
 360  * Expand arithmetic expression.  Backup to start of expression,
 361  * evaluate, place result in (backed up) result, adjust string position.
 362  */
 363 void
 364 expari(int flag)
 365 {
 366         char *p, *start;
 367         int result;
 368         int begoff;
 369         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 370         int quoted;
 371
 372
 373         /*
 374          * This routine is slightly over-complicated for
 375          * efficiency.  First we make sure there is
 376          * enough space for the result, which may be bigger
 377          * than the expression if we add exponentiation.  Next we
 378          * scan backwards looking for the start of arithmetic.  If the
 379          * next previous character is a CTLESC character, then we
 380          * have to rescan starting from the beginning since CTLESC
 381          * characters have to be processed left to right.
 382          */
 383 #if INT_MAX / 1000000000 >= 10 || INT_MIN / 1000000000 <= -10
 384 #error "integers with more than 10 digits are not supported"
 385 #endif
 386         CHECKSTRSPACE(12 - 2, expdest);
 387         USTPUTC('\0', expdest);
 388         start = stackblock();
 389         p = expdest - 2;
 390         while (p >= start && *p != CTLARI)
 391                 --p;
 392         if (p < start || *p != CTLARI)
 393                 error("missing CTLARI (shouldn't happen)");
 394         if (p > start && *(p - 1) == CTLESC)
 395                 for (p = start; *p != CTLARI; p++)
 396                         if (*p == CTLESC)
 397                                 p++;
 398
 399         if (p[1] == '"')
 400                 quoted=1;
 401         else
 402                 quoted=0;
 403         begoff = p - start;
 404         removerecordregions(begoff);
 405         if (quotes)
 406                 rmescapes(p+2);
 407         result = arith(p+2);
 408         fmtstr(p, 12, "%d", result);
 409         while (*p++)
 410                 ;
 411         if (quoted == 0)
 412                 recordregion(begoff, p - 1 - start, 0);
 413         result = expdest - p + 1;
 414         STADJUST(-result, expdest);
 415 }
 416
 417
 418 /*
 419  * Expand stuff in backwards quotes.
 420  */
 421
 422 STATIC void
 423 expbackq(union node *cmd, int quoted, int flag)
 424 {
 425         struct backcmd in;
 426         int i;
 427         char buf[128];
 428         char *p;
 429         char *dest = expdest;
 430         struct ifsregion saveifs, *savelastp;
 431         struct nodelist *saveargbackq;
 432         char lastc;
 433         int startloc = dest - stackblock();
 434         char const *syntax = quoted? DQSYNTAX : BASESYNTAX;
 435         int saveherefd;
 436         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 437
 438         INTOFF;
 439         saveifs = ifsfirst;
 440         savelastp = ifslastp;
 441         saveargbackq = argbackq;
 442         saveherefd = herefd;
 443         herefd = -1;
 444         p = grabstackstr(dest);
 445         evalbackcmd(cmd, &in);
 446         ungrabstackstr(p, dest);
 447         ifsfirst = saveifs;
 448         ifslastp = savelastp;
 449         argbackq = saveargbackq;
 450         herefd = saveherefd;
 451
 452         p = in.buf;
 453         lastc = '\0';
 454         for (;;) {
 455                 if (--in.nleft < 0) {
 456                         if (in.fd < 0)
 457                                 break;
 458                         while ((i = read(in.fd, buf, sizeof buf)) < 0 && errno == EINTR);
 459                         TRACE(("expbackq: read returns %d\n", i));
 460                         if (i <= 0)
 461                                 break;
 462                         p = buf;
 463                         in.nleft = i - 1;
 464                 }
 465                 lastc = *p++;
 466                 if (lastc != '\0') {
 467                         if (quotes && syntax[(int)lastc] == CCTL)
 468                                 STPUTC(CTLESC, dest);
 469                         STPUTC(lastc, dest);
 470                 }
 471         }
 472
 473         /* Eat all trailing newlines */
 474         for ( ; (dest - stackblock()) > startloc && *(dest-1) == '\n'; )
 475                 STUNPUTC(dest);
 476
 477         if (in.fd >= 0)
 478                 close(in.fd);
 479         if (in.buf)
 480                 ckfree(in.buf);
 481         if (in.jp)
 482                 exitstatus = waitforjob(in.jp, (int *)NULL);
 483         if (quoted == 0)
 484                 recordregion(startloc, dest - stackblock(), 0);
 485         TRACE(("evalbackq: size=%d: \"%.*s\"\n",
 486                 (dest - stackblock()) - startloc,
 487                 (dest - stackblock()) - startloc,
 488                 stackblock() + startloc));
 489         expdest = dest;
 490         INTON;
 491 }
 492
 493
 494
 495 STATIC int
 496 subevalvar(char *p, char *str, int strloc, int subtype, int startloc,
 497   int varflags)
 498 {
 499         char *startp;
 500         char *loc = NULL;
 501         char *q;
 502         int c = 0;
 503         int saveherefd = herefd;
 504         struct nodelist *saveargbackq = argbackq;
 505         int amount;
 506
 507         herefd = -1;
 508         argstr(p, 0);
 509         STACKSTRNUL(expdest);
 510         herefd = saveherefd;
 511         argbackq = saveargbackq;
 512         startp = stackblock() + startloc;
 513         if (str == NULL)
 514             str = stackblock() + strloc;
 515
 516         switch (subtype) {
 517         case VSASSIGN:
 518                 setvar(str, startp, 0);
 519                 amount = startp - expdest;
 520                 STADJUST(amount, expdest);
 521                 varflags &= ~VSNUL;
 522                 if (c != 0)
 523                         *loc = c;
 524                 return 1;
 525
 526         case VSQUESTION:
 527                 if (*p != CTLENDVAR) {
 528                         outfmt(&errout, "%s\n", startp);
 529                         error((char *)NULL);
 530                 }
 531                 error("%.*s: parameter %snot set", p - str - 1,
 532                       str, (varflags & VSNUL) ? "null or "
 533                                               : nullstr);
 534                 return 0;
 535
 536         case VSTRIMLEFT:
 537                 for (loc = startp; loc < str; loc++) {
 538                         c = *loc;
 539                         *loc = '\0';
 540                         if (patmatch(str, startp, varflags & VSQUOTE)) {
 541                                 *loc = c;
 542                                 goto recordleft;
 543                         }
 544                         *loc = c;
 545                         if ((varflags & VSQUOTE) && *loc == CTLESC)
 546                                 loc++;
 547                 }
 548                 return 0;
 549
 550         case VSTRIMLEFTMAX:
 551                 for (loc = str - 1; loc >= startp;) {
 552                         c = *loc;
 553                         *loc = '\0';
 554                         if (patmatch(str, startp, varflags & VSQUOTE)) {
 555                                 *loc = c;
 556                                 goto recordleft;
 557                         }
 558                         *loc = c;
 559                         loc--;
 560                         if ((varflags & VSQUOTE) && loc > startp &&
 561                             *(loc - 1) == CTLESC) {
 562                                 for (q = startp; q < loc; q++)
 563                                         if (*q == CTLESC)
 564                                                 q++;
 565                                 if (q > loc)
 566                                         loc--;
 567                         }
 568                 }
 569                 return 0;
 570
 571         case VSTRIMRIGHT:
 572                 for (loc = str - 1; loc >= startp;) {
 573                         if (patmatch(str, loc, varflags & VSQUOTE)) {
 574                                 amount = loc - expdest;
 575                                 STADJUST(amount, expdest);
 576                                 return 1;
 577                         }
 578                         loc--;
 579                         if ((varflags & VSQUOTE) && loc > startp &&
 580                             *(loc - 1) == CTLESC) {
 581                                 for (q = startp; q < loc; q++)
 582                                         if (*q == CTLESC)
 583                                                 q++;
 584                                 if (q > loc)
 585                                         loc--;
 586                         }
 587                 }
 588                 return 0;
 589
 590         case VSTRIMRIGHTMAX:
 591                 for (loc = startp; loc < str - 1; loc++) {
 592                         if (patmatch(str, loc, varflags & VSQUOTE)) {
 593                                 amount = loc - expdest;
 594                                 STADJUST(amount, expdest);
 595                                 return 1;
 596                         }
 597                         if ((varflags & VSQUOTE) && *loc == CTLESC)
 598                                 loc++;
 599                 }
 600                 return 0;
 601
 602
 603         default:
 604                 abort();
 605         }
 606
 607 recordleft:
 608         amount = ((str - 1) - (loc - startp)) - expdest;
 609         STADJUST(amount, expdest);
 610         while (loc != str - 1)
 611                 *startp++ = *loc++;
 612         return 1;
 613 }
 614
 615
 616 /*
 617  * Expand a variable, and return a pointer to the next character in the
 618  * input string.
 619  */
 620
 621 STATIC char *
 622 evalvar(char *p, int flag)
 623 {
 624         int subtype;
 625         int varflags;
 626         char *var;
 627         char *val;
 628         int patloc;
 629         int c;
 630         int set;
 631         int special;
 632         int startloc;
 633         int varlen;
 634         int easy;
 635         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 636
 637         varflags = *p++;
 638         subtype = varflags & VSTYPE;
 639         var = p;
 640         special = 0;
 641         if (! is_name(*p))
 642                 special = 1;
 643         p = strchr(p, '=') + 1;
 644 again: /* jump here after setting a variable with ${var=text} */
 645         if (special) {
 646                 set = varisset(var, varflags & VSNUL);
 647                 val = NULL;
 648         } else {
 649                 val = bltinlookup(var, 1);
 650                 if (val == NULL || ((varflags & VSNUL) && val[0] == '\0')) {
 651                         val = NULL;
 652                         set = 0;
 653                 } else
 654                         set = 1;
 655         }
 656         varlen = 0;
 657         startloc = expdest - stackblock();
 658         if (!set && uflag) {
 659                 switch (subtype) {
 660                 case VSNORMAL:
 661                 case VSTRIMLEFT:
 662                 case VSTRIMLEFTMAX:
 663                 case VSTRIMRIGHT:
 664                 case VSTRIMRIGHTMAX:
 665                 case VSLENGTH:
 666                         error("%.*s: parameter not set", p - var - 1, var);
 667                 }
 668         }
 669         if (set && subtype != VSPLUS) {
 670                 /* insert the value of the variable */
 671                 if (special) {
 672                         varvalue(var, varflags & VSQUOTE, flag & EXP_FULL);
 673                         if (subtype == VSLENGTH) {
 674                                 varlen = expdest - stackblock() - startloc;
 675                                 STADJUST(-varlen, expdest);
 676                         }
 677                 } else {
 678                         char const *syntax = (varflags & VSQUOTE) ? DQSYNTAX
 679                                                                   : BASESYNTAX;
 680
 681                         if (subtype == VSLENGTH) {
 682                                 for (;*val; val++)
 683                                         varlen++;
 684                         }
 685                         else {
 686                                 while (*val) {
 687                                         if (quotes &&
 688                                             syntax[(int)*val] == CCTL)
 689                                                 STPUTC(CTLESC, expdest);
 690                                         STPUTC(*val++, expdest);
 691                                 }
 692
 693                         }
 694                 }
 695         }
 696
 697         if (subtype == VSPLUS)
 698                 set = ! set;
 699
 700         easy = ((varflags & VSQUOTE) == 0 ||
 701                 (*var == '@' && shellparam.nparam != 1));
 702
 703
 704         switch (subtype) {
 705         case VSLENGTH:
 706                 expdest = cvtnum(varlen, expdest);
 707                 goto record;
 708
 709         case VSNORMAL:
 710                 if (!easy)
 711                         break;
 712 record:
 713                 recordregion(startloc, expdest - stackblock(),
 714                              varflags & VSQUOTE);
 715                 break;
 716
 717         case VSPLUS:
 718         case VSMINUS:
 719                 if (!set) {
 720                         argstr(p, flag);
 721                         break;
 722                 }
 723                 if (easy)
 724                         goto record;
 725                 break;
 726
 727         case VSTRIMLEFT:
 728         case VSTRIMLEFTMAX:
 729         case VSTRIMRIGHT:
 730         case VSTRIMRIGHTMAX:
 731                 if (!set)
 732                         break;
 733                 /*
 734                  * Terminate the string and start recording the pattern
 735                  * right after it
 736                  */
 737                 STPUTC('\0', expdest);
 738                 patloc = expdest - stackblock();
 739                 if (subevalvar(p, NULL, patloc, subtype,
 740                                startloc, varflags) == 0) {
 741                         int amount = (expdest - stackblock() - patloc) + 1;
 742                         STADJUST(-amount, expdest);
 743                 }
 744                 /* Remove any recorded regions beyond start of variable */
 745                 removerecordregions(startloc);
 746                 goto record;
 747
 748         case VSASSIGN:
 749         case VSQUESTION:
 750                 if (!set) {
 751                         if (subevalvar(p, var, 0, subtype, startloc, varflags)) {
 752                                 varflags &= ~VSNUL;
 753                                 /*
 754                                  * Remove any recorded regions beyond
 755                                  * start of variable
 756                                  */
 757                                 removerecordregions(startloc);
 758                                 goto again;
 759                         }
 760                         break;
 761                 }
 762                 if (easy)
 763                         goto record;
 764                 break;
 765
 766         default:
 767                 abort();
 768         }
 769
 770         if (subtype != VSNORMAL) {      /* skip to end of alternative */
 771                 int nesting = 1;
 772                 for (;;) {
 773                         if ((c = *p++) == CTLESC)
 774                                 p++;
 775                         else if (c == CTLBACKQ || c == (CTLBACKQ|CTLQUOTE)) {
 776                                 if (set)
 777                                         argbackq = argbackq->next;
 778                         } else if (c == CTLVAR) {
 779                                 if ((*p++ & VSTYPE) != VSNORMAL)
 780                                         nesting++;
 781                         } else if (c == CTLENDVAR) {
 782                                 if (--nesting == 0)
 783                                         break;
 784                         }
 785                 }
 786         }
 787         return p;
 788 }
 789
 790
 791
 792 /*
 793  * Test whether a specialized variable is set.
 794  */
 795
 796 STATIC int
 797 varisset(char *name, int nulok)
 798 {
 799
 800         if (*name == '!')
 801                 return backgndpid != -1;
 802         else if (*name == '@' || *name == '*') {
 803                 if (*shellparam.p == NULL)
 804                         return 0;
 805
 806                 if (nulok) {
 807                         char **av;
 808
 809                         for (av = shellparam.p; *av; av++)
 810                                 if (**av != '\0')
 811                                         return 1;
 812                         return 0;
 813                 }
 814         } else if (is_digit(*name)) {
 815                 char *ap;
 816                 int num = atoi(name);
 817
 818                 if (num > shellparam.nparam)
 819                         return 0;
 820
 821                 if (num == 0)
 822                         ap = arg0;
 823                 else
 824                         ap = shellparam.p[num - 1];
 825
 826                 if (nulok && (ap == NULL || *ap == '\0'))
 827                         return 0;
 828         }
 829         return 1;
 830 }
 831
 832
 833
 834 /*
 835  * Add the value of a specialized variable to the stack string.
 836  */
 837
 838 STATIC void
 839 varvalue(char *name, int quoted, int allow_split)
 840 {
 841         int num;
 842         char *p;
 843         int i;
 844         char sep;
 845         char **ap;
 846         char const *syntax;
 847
 848 #define STRTODEST(p) \
 849         do {\
 850         if (allow_split) { \
 851                 syntax = quoted? DQSYNTAX : BASESYNTAX; \
 852                 while (*p) { \
 853                         if (syntax[(int)*p] == CCTL) \
 854                                 STPUTC(CTLESC, expdest); \
 855                         STPUTC(*p++, expdest); \
 856                 } \
 857         } else \
 858                 while (*p) \
 859                         STPUTC(*p++, expdest); \
 860         } while (0)
 861
 862
 863         switch (*name) {
 864         case '$':
 865                 num = rootpid;
 866                 goto numvar;
 867         case '?':
 868                 num = oexitstatus;
 869                 goto numvar;
 870         case '#':
 871                 num = shellparam.nparam;
 872                 goto numvar;
 873         case '!':
 874                 num = backgndpid;
 875 numvar:
 876                 expdest = cvtnum(num, expdest);
 877                 break;
 878         case '-':
 879                 for (i = 0 ; i < NOPTS ; i++) {
 880                         if (optlist[i].val)
 881                                 STPUTC(optlist[i].letter, expdest);
 882                 }
 883                 break;
 884         case '@':
 885                 if (allow_split && quoted) {
 886                         for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
 887                                 STRTODEST(p);
 888                                 if (*ap)
 889                                         STPUTC('\0', expdest);
 890                         }
 891                         break;
 892                 }
 893                 /* fall through */
 894         case '*':
 895                 if (ifsset() != 0)
 896                         sep = ifsval()[0];
 897                 else
 898                         sep = ' ';
 899                 for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
 900                         STRTODEST(p);
 901                         if (*ap && sep)
 902                                 STPUTC(sep, expdest);
 903                 }
 904                 break;
 905         case '0':
 906                 p = arg0;
 907                 STRTODEST(p);
 908                 break;
 909         default:
 910                 if (is_digit(*name)) {
 911                         num = atoi(name);
 912                         if (num > 0 && num <= shellparam.nparam) {
 913                                 p = shellparam.p[num - 1];
 914                                 STRTODEST(p);
 915                         }
 916                 }
 917                 break;
 918         }
 919 }
 920
 921
 922
 923 /*
 924  * Record the the fact that we have to scan this region of the
 925  * string for IFS characters.
 926  */
 927
 928 STATIC void
 929 recordregion(int start, int end, int nulonly)
 930 {
 931         struct ifsregion *ifsp;
 932
 933         if (ifslastp == NULL) {
 934                 ifsp = &ifsfirst;
 935         } else {
 936                 ifsp = (struct ifsregion *)ckmalloc(sizeof (struct ifsregion));
 937                 ifslastp->next = ifsp;
 938         }
 939         ifslastp = ifsp;
 940         ifslastp->next = NULL;
 941         ifslastp->begoff = start;
 942         ifslastp->endoff = end;
 943         ifslastp->nulonly = nulonly;
 944 }
 945
 946
 947
 948 /*
 949  * Break the argument string into pieces based upon IFS and add the
 950  * strings to the argument list.  The regions of the string to be
 951  * searched for IFS characters have been stored by recordregion.
 952  */
 953 STATIC void
 954 ifsbreakup(char *string, struct arglist *arglist)
 955 {
 956         struct ifsregion *ifsp;
 957         struct strlist *sp;
 958         char *start;
 959         char *p;
 960         char *q;
 961         const char *ifs;
 962         int ifsspc;
 963         int nulonly;
 964
 965
 966         start = string;
 967         ifsspc = 0;
 968         nulonly = 0;
 969         if (ifslastp != NULL) {
 970                 ifsp = &ifsfirst;
 971                 do {
 972                         p = string + ifsp->begoff;
 973                         nulonly = ifsp->nulonly;
 974                         ifs = nulonly ? nullstr :
 975                                 ( ifsset() ? ifsval() : " \t\n" );
 976                         ifsspc = 0;
 977                         while (p < string + ifsp->endoff) {
 978                                 q = p;
 979                                 if (*p == CTLESC)
 980                                         p++;
 981                                 if (strchr(ifs, *p)) {
 982                                         if (!nulonly)
 983                                                 ifsspc = (strchr(" \t\n", *p) != NULL);
 984                                         /* Ignore IFS whitespace at start */
 985                                         if (q == start && ifsspc) {
 986                                                 p++;
 987                                                 start = p;
 988                                                 continue;
 989                                         }
 990                                         *q = '\0';
 991                                         sp = (struct strlist *)stalloc(sizeof *sp);
 992                                         sp->text = start;
 993                                         *arglist->lastp = sp;
 994                                         arglist->lastp = &sp->next;
 995                                         p++;
 996                                         if (!nulonly) {
 997                                                 for (;;) {
 998                                                         if (p >= string + ifsp->endoff) {
 999                                                                 break;
1000                                                         }
1001                                                         q = p;
1002                                                         if (*p == CTLESC)
1003                                                                 p++;
1004                                                         if (strchr(ifs, *p) == NULL ) {
1005                                                                 p = q;
1006                                                                 break;
1007                                                         } else if (strchr(" \t\n",*p) == NULL) {
1008                                                                 if (ifsspc) {
1009                                                                         p++;
1010                                                                         ifsspc = 0;
1011                                                                 } else {
1012                                                                         p = q;
1013                                                                         break;
1014                                                                 }
1015                                                         } else
1016                                                                 p++;
1017                                                 }
1018                                         }
1019                                         start = p;
1020                                 } else
1021                                         p++;
1022                         }
1023                 } while ((ifsp = ifsp->next) != NULL);
1024                 if (*start || (!ifsspc && start > string &&
1025                         (nulonly || 1))) {
1026                         sp = (struct strlist *)stalloc(sizeof *sp);
1027                         sp->text = start;
1028                         *arglist->lastp = sp;
1029                         arglist->lastp = &sp->next;
1030                 }
1031         } else {
1032                 sp = (struct strlist *)stalloc(sizeof *sp);
1033                 sp->text = start;
1034                 *arglist->lastp = sp;
1035                 arglist->lastp = &sp->next;
1036         }
1037 }
1038
1039
1040
1041 /*
1042  * Expand shell metacharacters.  At this point, the only control characters
1043  * should be escapes.  The results are stored in the list exparg.
1044  */
1045
1046 STATIC char *expdir;
1047
1048
1049 STATIC void
1050 expandmeta(struct strlist *str, int flag __unused)
1051 {
1052         char *p;
1053         struct strlist **savelastp;
1054         struct strlist *sp;
1055         char c;
1056         /* TODO - EXP_REDIR */
1057
1058         while (str) {
1059                 if (fflag)
1060                         goto nometa;
1061                 p = str->text;
1062                 for (;;) {                      /* fast check for meta chars */
1063                         if ((c = *p++) == '\0')
1064                                 goto nometa;
1065                         if (c == '*' || c == '?' || c == '[' || c == '!')
1066                                 break;
1067                 }
1068                 savelastp = exparg.lastp;
1069                 INTOFF;
1070                 if (expdir == NULL) {
1071                         int i = strlen(str->text);
1072                         expdir = ckmalloc(i < 2048 ? 2048 : i); /* XXX */
1073                 }
1074
1075                 expmeta(expdir, str->text);
1076                 ckfree(expdir);
1077                 expdir = NULL;
1078                 INTON;
1079                 if (exparg.lastp == savelastp) {
1080                         /*
1081                          * no matches
1082                          */
1083 nometa:
1084                         *exparg.lastp = str;
1085                         rmescapes(str->text);
1086                         exparg.lastp = &str->next;
1087                 } else {
1088                         *exparg.lastp = NULL;
1089                         *savelastp = sp = expsort(*savelastp);
1090                         while (sp->next != NULL)
1091                                 sp = sp->next;
1092                         exparg.lastp = &sp->next;
1093                 }
1094                 str = str->next;
1095         }
1096 }
1097
1098
1099 /*
1100  * Do metacharacter (i.e. *, ?, [...]) expansion.
1101  */
1102
1103 STATIC void
1104 expmeta(char *enddir, char *name)
1105 {
1106         char *p;
1107         const char *q;
1108         char *start;
1109         char *endname;
1110         int metaflag;
1111         struct stat statb;
1112         DIR *dirp;
1113         struct dirent *dp;
1114         int atend;
1115         int matchdot;
1116
1117         metaflag = 0;
1118         start = name;
1119         for (p = name ; ; p++) {
1120                 if (*p == '*' || *p == '?')
1121                         metaflag = 1;
1122                 else if (*p == '[') {
1123                         q = p + 1;
1124                         if (*q == '!' || *q == '^')
1125                                 q++;
1126                         for (;;) {
1127                                 while (*q == CTLQUOTEMARK)
1128                                         q++;
1129                                 if (*q == CTLESC)
1130                                         q++;
1131                                 if (*q == '/' || *q == '\0')
1132                                         break;
1133                                 if (*++q == ']') {
1134                                         metaflag = 1;
1135                                         break;
1136                                 }
1137                         }
1138                 } else if (*p == '!' && p[1] == '!'     && (p == name || p[-1] == '/')) {
1139                         metaflag = 1;
1140                 } else if (*p == '\0')
1141                         break;
1142                 else if (*p == CTLQUOTEMARK)
1143                         continue;
1144                 else if (*p == CTLESC)
1145                         p++;
1146                 if (*p == '/') {
1147                         if (metaflag)
1148                                 break;
1149                         start = p + 1;
1150                 }
1151         }
1152         if (metaflag == 0) {    /* we've reached the end of the file name */
1153                 if (enddir != expdir)
1154                         metaflag++;
1155                 for (p = name ; ; p++) {
1156                         if (*p == CTLQUOTEMARK)
1157                                 continue;
1158                         if (*p == CTLESC)
1159                                 p++;
1160                         *enddir++ = *p;
1161                         if (*p == '\0')
1162                                 break;
1163                 }
1164                 if (metaflag == 0 || lstat(expdir, &statb) >= 0)
1165                         addfname(expdir);
1166                 return;
1167         }
1168         endname = p;
1169         if (start != name) {
1170                 p = name;
1171                 while (p < start) {
1172                         while (*p == CTLQUOTEMARK)
1173                                 p++;
1174                         if (*p == CTLESC)
1175                                 p++;
1176                         *enddir++ = *p++;
1177                 }
1178         }
1179         if (enddir == expdir) {
1180                 q = ".";
1181         } else if (enddir == expdir + 1 && *expdir == '/') {
1182                 q = "/";
1183         } else {
1184                 q = expdir;
1185                 enddir[-1] = '\0';
1186         }
1187         if ((dirp = opendir(q)) == NULL)
1188                 return;
1189         if (enddir != expdir)
1190                 enddir[-1] = '/';
1191         if (*endname == 0) {
1192                 atend = 1;
1193         } else {
1194                 atend = 0;
1195                 *endname++ = '\0';
1196         }
1197         matchdot = 0;
1198         p = start;
1199         while (*p == CTLQUOTEMARK)
1200                 p++;
1201         if (*p == CTLESC)
1202                 p++;
1203         if (*p == '.')
1204                 matchdot++;
1205         while (! int_pending() && (dp = readdir(dirp)) != NULL) {
1206                 if (dp->d_name[0] == '.' && ! matchdot)
1207                         continue;
1208                 if (patmatch(start, dp->d_name, 0)) {
1209                         if (atend) {
1210                                 scopy(dp->d_name, enddir);
1211                                 addfname(expdir);
1212                         } else {
1213                                 char *t;
1214                                 for (t = enddir, q = dp->d_name;
1215                                      (*t++ = *q++) != '\0';)
1216                                         continue;
1217                                 t[-1] = '/';
1218                                 expmeta(t, endname);
1219                         }
1220                 }
1221         }
1222         closedir(dirp);
1223         if (! atend)
1224                 endname[-1] = '/';
1225 }
1226
1227
1228 /*
1229  * Add a file name to the list.
1230  */
1231
1232 STATIC void
1233 addfname(char *name)
1234 {
1235         char *p;
1236         struct strlist *sp;
1237
1238         p = stalloc(strlen(name) + 1);
1239         scopy(name, p);
1240         sp = (struct strlist *)stalloc(sizeof *sp);
1241         sp->text = p;
1242         *exparg.lastp = sp;
1243         exparg.lastp = &sp->next;
1244 }
1245
1246
1247 /*
1248  * Sort the results of file name expansion.  It calculates the number of
1249  * strings to sort and then calls msort (short for merge sort) to do the
1250  * work.
1251  */
1252
1253 STATIC struct strlist *
1254 expsort(struct strlist *str)
1255 {
1256         int len;
1257         struct strlist *sp;
1258
1259         len = 0;
1260         for (sp = str ; sp ; sp = sp->next)
1261                 len++;
1262         return msort(str, len);
1263 }
1264
1265
1266 STATIC struct strlist *
1267 msort(struct strlist *list, int len)
1268 {
1269         struct strlist *p, *q = NULL;
1270         struct strlist **lpp;
1271         int half;
1272         int n;
1273
1274         if (len <= 1)
1275                 return list;
1276         half = len >> 1;
1277         p = list;
1278         for (n = half ; --n >= 0 ; ) {
1279                 q = p;
1280                 p = p->next;
1281         }
1282         q->next = NULL;                 /* terminate first half of list */
1283         q = msort(list, half);          /* sort first half of list */
1284         p = msort(p, len - half);               /* sort second half */
1285         lpp = &list;
1286         for (;;) {
1287                 if (strcmp(p->text, q->text) < 0) {
1288                         *lpp = p;
1289                         lpp = &p->next;
1290                         if ((p = *lpp) == NULL) {
1291                                 *lpp = q;
1292                                 break;
1293                         }
1294                 } else {
1295                         *lpp = q;
1296                         lpp = &q->next;
1297                         if ((q = *lpp) == NULL) {
1298                                 *lpp = p;
1299                                 break;
1300                         }
1301                 }
1302         }
1303         return list;
1304 }
1305
1306
1307
1308 /*
1309  * Returns true if the pattern matches the string.
1310  */
1311
1312 int
1313 patmatch(char *pattern, char *string, int squoted)
1314 {
1315 #ifdef notdef
1316         if (pattern[0] == '!' && pattern[1] == '!')
1317                 return 1 - pmatch(pattern + 2, string);
1318         else
1319 #endif
1320                 return pmatch(pattern, string, squoted);
1321 }
1322
1323
1324 STATIC int
1325 pmatch(char *pattern, char *string, int squoted)
1326 {
1327         char *p, *q;
1328         char c;
1329
1330         p = pattern;
1331         q = string;
1332         for (;;) {
1333                 switch (c = *p++) {
1334                 case '\0':
1335                         goto breakloop;
1336                 case CTLESC:
1337                         if (squoted && *q == CTLESC)
1338                                 q++;
1339                         if (*q++ != *p++)
1340                                 return 0;
1341                         break;
1342                 case CTLQUOTEMARK:
1343                         continue;
1344                 case '?':
1345                         if (squoted && *q == CTLESC)
1346                                 q++;
1347                         if (*q++ == '\0')
1348                                 return 0;
1349                         break;
1350                 case '*':
1351                         c = *p;
1352                         while (c == CTLQUOTEMARK || c == '*')
1353                                 c = *++p;
1354                         if (c != CTLESC &&  c != CTLQUOTEMARK &&
1355                             c != '?' && c != '*' && c != '[') {
1356                                 while (*q != c) {
1357                                         if (squoted && *q == CTLESC &&
1358                                             q[1] == c)
1359                                                 break;
1360                                         if (*q == '\0')
1361                                                 return 0;
1362                                         if (squoted && *q == CTLESC)
1363                                                 q++;
1364                                         q++;
1365                                 }
1366                         }
1367                         do {
1368                                 if (pmatch(p, q, squoted))
1369                                         return 1;
1370                                 if (squoted && *q == CTLESC)
1371                                         q++;
1372                         } while (*q++ != '\0');
1373                         return 0;
1374                 case '[': {
1375                         char *endp;
1376                         int invert, found;
1377                         char chr;
1378
1379                         endp = p;
1380                         if (*endp == '!' || *endp == '^')
1381                                 endp++;
1382                         for (;;) {
1383                                 while (*endp == CTLQUOTEMARK)
1384                                         endp++;
1385                                 if (*endp == '\0')
1386                                         goto dft;               /* no matching ] */
1387                                 if (*endp == CTLESC)
1388                                         endp++;
1389                                 if (*++endp == ']')
1390                                         break;
1391                         }
1392                         invert = 0;
1393                         if (*p == '!' || *p == '^') {
1394                                 invert++;
1395                                 p++;
1396                         }
1397                         found = 0;
1398                         chr = *q++;
1399                         if (squoted && chr == CTLESC)
1400                                 chr = *q++;
1401                         if (chr == '\0')
1402                                 return 0;
1403                         c = *p++;
1404                         do {
1405                                 if (c == CTLQUOTEMARK)
1406                                         continue;
1407                                 if (c == CTLESC)
1408                                         c = *p++;
1409                                 if (*p == '-' && p[1] != ']') {
1410                                         p++;
1411                                         while (*p == CTLQUOTEMARK)
1412                                                 p++;
1413                                         if (*p == CTLESC)
1414                                                 p++;
1415                                         if (   collate_range_cmp(chr, c) >= 0
1416                                             && collate_range_cmp(chr, *p) <= 0
1417                                            )
1418                                                 found = 1;
1419                                         p++;
1420                                 } else {
1421                                         if (chr == c)
1422                                                 found = 1;
1423                                 }
1424                         } while ((c = *p++) != ']');
1425                         if (found == invert)
1426                                 return 0;
1427                         break;
1428                 }
1429 dft:            default:
1430                         if (squoted && *q == CTLESC)
1431                                 q++;
1432                         if (*q++ != c)
1433                                 return 0;
1434                         break;
1435                 }
1436         }
1437 breakloop:
1438         if (*q != '\0')
1439                 return 0;
1440         return 1;
1441 }
1442
1443
1444
1445 /*
1446  * Remove any CTLESC characters from a string.
1447  */
1448
1449 void
1450 rmescapes(char *str)
1451 {
1452         char *p, *q;
1453
1454         p = str;
1455         while (*p != CTLESC && *p != CTLQUOTEMARK) {
1456                 if (*p++ == '\0')
1457                         return;
1458         }
1459         q = p;
1460         while (*p) {
1461                 if (*p == CTLQUOTEMARK) {
1462                         p++;
1463                         continue;
1464                 }
1465                 if (*p == CTLESC)
1466                         p++;
1467                 *q++ = *p++;
1468         }
1469         *q = '\0';
1470 }
1471
1472
1473
1474 /*
1475  * See if a pattern matches in a case statement.
1476  */
1477
1478 int
1479 casematch(union node *pattern, char *val)
1480 {
1481         struct stackmark smark;
1482         int result;
1483         char *p;
1484
1485         setstackmark(&smark);
1486         argbackq = pattern->narg.backquote;
1487         STARTSTACKSTR(expdest);
1488         ifslastp = NULL;
1489         argstr(pattern->narg.text, EXP_TILDE | EXP_CASE);
1490         STPUTC('\0', expdest);
1491         p = grabstackstr(expdest);
1492         result = patmatch(p, val, 0);
1493         popstackmark(&smark);
1494         return result;
1495 }
1496
1497 /*
1498  * Our own itoa().
1499  */
1500
1501 STATIC char *
1502 cvtnum(int num, char *buf)
1503 {
1504         char temp[32];
1505         int neg = num < 0;
1506         char *p = temp + 31;
1507
1508         temp[31] = '\0';
1509
1510         do {
1511                 *--p = num % 10 + '0';
1512         } while ((num /= 10) != 0);
1513
1514         if (neg)
1515                 *--p = '-';
1516
1517         while (*p)
1518                 STPUTC(*p++, buf);
1519         return buf;
1520 }