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 1.8 2007/01/07 08:26:55 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 #include <string.h>
  52
  53 /*
  54  * Routines to expand arguments to commands.  We have to deal with
  55  * backquotes, shell variables, and file metacharacters.
  56  */
  57
  58 #include "shell.h"
  59 #include "main.h"
  60 #include "nodes.h"
  61 #include "eval.h"
  62 #include "expand.h"
  63 #include "syntax.h"
  64 #include "parser.h"
  65 #include "jobs.h"
  66 #include "options.h"
  67 #include "var.h"
  68 #include "input.h"
  69 #include "output.h"
  70 #include "memalloc.h"
  71 #include "error.h"
  72 #include "mystring.h"
  73 #include "arith.h"
  74 #include "show.h"
  75
  76 /*
  77  * Structure specifying which parts of the string should be searched
  78  * for IFS characters.
  79  */
  80
  81 struct ifsregion {
  82         struct ifsregion *next; /* next region in list */
  83         int begoff;             /* offset of start of region */
  84         int endoff;             /* offset of end of region */
  85         int nulonly;            /* search for nul bytes only */
  86 };
  87
  88
  89 STATIC char *expdest;                   /* output of current string */
  90 STATIC struct nodelist *argbackq;       /* list of back quote expressions */
  91 STATIC struct ifsregion ifsfirst;       /* first struct in list of ifs regions */
  92 STATIC struct ifsregion *ifslastp;      /* last struct in list */
  93 STATIC struct arglist exparg;           /* holds expanded arg list */
  94
  95 STATIC void argstr(char *, int);
  96 STATIC char *exptilde(char *, int);
  97 STATIC void expbackq(union node *, int, int);
  98 STATIC int subevalvar(char *, char *, int, int, int, int);
  99 STATIC char *evalvar(char *, int);
 100 STATIC int varisset(char *, int);
 101 STATIC void varvalue(char *, int, int);
 102 STATIC void recordregion(int, int, int);
 103 STATIC void removerecordregions(int);
 104 STATIC void ifsbreakup(char *, struct arglist *);
 105 STATIC void expandmeta(struct strlist *, int);
 106 STATIC void expmeta(char *, char *);
 107 STATIC void addfname(char *);
 108 STATIC struct strlist *expsort(struct strlist *);
 109 STATIC struct strlist *msort(struct strlist *, int);
 110 STATIC int pmatch(char *, char *, int);
 111 STATIC char *cvtnum(int, char *);
 112 STATIC int collate_range_cmp(int, int);
 113
 114 STATIC int
 115 collate_range_cmp (int c1, int c2)
 116 {
 117         static char s1[2], s2[2];
 118         int ret;
 119
 120         c1 &= UCHAR_MAX;
 121         c2 &= UCHAR_MAX;
 122         if (c1 == c2)
 123                 return (0);
 124         s1[0] = c1;
 125         s2[0] = c2;
 126         if ((ret = strcoll(s1, s2)) != 0)
 127                 return (ret);
 128         return (c1 - c2);
 129 }
 130
 131 extern int oexitstatus;
 132
 133 /*
 134  * Expand shell variables and backquotes inside a here document.
 135  *      union node *arg         the document
 136  *      int fd;                 where to write the expanded version
 137  */
 138
 139 void
 140 expandhere(union node *arg, int fd)
 141 {
 142         herefd = fd;
 143         expandarg(arg, (struct arglist *)NULL, 0);
 144         xwrite(fd, stackblock(), expdest - stackblock());
 145 }
 146
 147
 148 /*
 149  * Perform variable substitution and command substitution on an argument,
 150  * placing the resulting list of arguments in arglist.  If EXP_FULL is true,
 151  * perform splitting and file name expansion.  When arglist is NULL, perform
 152  * here document expansion.
 153  */
 154
 155 void
 156 expandarg(union node *arg, struct arglist *arglist, int flag)
 157 {
 158         struct strlist *sp;
 159         char *p;
 160
 161         argbackq = arg->narg.backquote;
 162         STARTSTACKSTR(expdest);
 163         ifsfirst.next = NULL;
 164         ifslastp = NULL;
 165         argstr(arg->narg.text, flag);
 166         if (arglist == NULL) {
 167                 return;                 /* here document expanded */
 168         }
 169         STPUTC('\0', expdest);
 170         p = grabstackstr(expdest);
 171         exparg.lastp = &exparg.list;
 172         /*
 173          * TODO - EXP_REDIR
 174          */
 175         if (flag & EXP_FULL) {
 176                 ifsbreakup(p, &exparg);
 177                 *exparg.lastp = NULL;
 178                 exparg.lastp = &exparg.list;
 179                 expandmeta(exparg.list, flag);
 180         } else {
 181                 if (flag & EXP_REDIR) /*XXX - for now, just remove escapes */
 182                         rmescapes(p);
 183                 sp = (struct strlist *)stalloc(sizeof (struct strlist));
 184                 sp->text = p;
 185                 *exparg.lastp = sp;
 186                 exparg.lastp = &sp->next;
 187         }
 188         while (ifsfirst.next != NULL) {
 189                 struct ifsregion *ifsp;
 190                 INTOFF;
 191                 ifsp = ifsfirst.next->next;
 192                 ckfree(ifsfirst.next);
 193                 ifsfirst.next = ifsp;
 194                 INTON;
 195         }
 196         *exparg.lastp = NULL;
 197         if (exparg.list) {
 198                 *arglist->lastp = exparg.list;
 199                 arglist->lastp = exparg.lastp;
 200         }
 201 }
 202
 203
 204
 205 /*
 206  * Perform variable and command substitution.  If EXP_FULL is set, output CTLESC
 207  * characters to allow for further processing.  Otherwise treat
 208  * $@ like $* since no splitting will be performed.
 209  */
 210
 211 STATIC void
 212 argstr(char *p, int flag)
 213 {
 214         char c;
 215         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);  /* do CTLESC */
 216         int firsteq = 1;
 217
 218         if (*p == '~' && (flag & (EXP_TILDE | EXP_VARTILDE)))
 219                 p = exptilde(p, flag);
 220         for (;;) {
 221                 switch (c = *p++) {
 222                 case '\0':
 223                 case CTLENDVAR: /* ??? */
 224                         goto breakloop;
 225                 case CTLQUOTEMARK:
 226                         /* "$@" syntax adherence hack */
 227                         if (p[0] == CTLVAR && p[2] == '@' && p[3] == '=')
 228                                 break;
 229                         if ((flag & EXP_FULL) != 0)
 230                                 STPUTC(c, expdest);
 231                         break;
 232                 case CTLESC:
 233                         if (quotes)
 234                                 STPUTC(c, expdest);
 235                         c = *p++;
 236                         STPUTC(c, expdest);
 237                         break;
 238                 case CTLVAR:
 239                         p = evalvar(p, flag);
 240                         break;
 241                 case CTLBACKQ:
 242                 case CTLBACKQ|CTLQUOTE:
 243                         expbackq(argbackq->n, c & CTLQUOTE, flag);
 244                         argbackq = argbackq->next;
 245                         break;
 246                 case CTLENDARI:
 247                         expari(flag);
 248                         break;
 249                 case ':':
 250                 case '=':
 251                         /*
 252                          * sort of a hack - expand tildes in variable
 253                          * assignments (after the first '=' and after ':'s).
 254                          */
 255                         STPUTC(c, expdest);
 256                         if (flag & EXP_VARTILDE && *p == '~') {
 257                                 if (c == '=') {
 258                                         if (firsteq)
 259                                                 firsteq = 0;
 260                                         else
 261                                                 break;
 262                                 }
 263                                 p = exptilde(p, flag);
 264                         }
 265                         break;
 266                 default:
 267                         STPUTC(c, expdest);
 268                 }
 269         }
 270 breakloop:;
 271 }
 272
 273 STATIC char *
 274 exptilde(char *p, int flag)
 275 {
 276         char c, *startp = p;
 277         struct passwd *pw;
 278         char *home;
 279         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 280
 281         while ((c = *p) != '\0') {
 282                 switch(c) {
 283                 case CTLESC:
 284                         return (startp);
 285                 case CTLQUOTEMARK:
 286                         return (startp);
 287                 case ':':
 288                         if (flag & EXP_VARTILDE)
 289                                 goto done;
 290                         break;
 291                 case '/':
 292                         goto done;
 293                 }
 294                 p++;
 295         }
 296 done:
 297         *p = '\0';
 298         if (*(startp+1) == '\0') {
 299                 if ((home = lookupvar("HOME")) == NULL)
 300                         goto lose;
 301         } else {
 302                 if ((pw = getpwnam(startp+1)) == NULL)
 303                         goto lose;
 304                 home = pw->pw_dir;
 305         }
 306         if (*home == '\0')
 307                 goto lose;
 308         *p = c;
 309         while ((c = *home++) != '\0') {
 310                 if (quotes && SQSYNTAX[(int)c] == CCTL)
 311                         STPUTC(CTLESC, expdest);
 312                 STPUTC(c, expdest);
 313         }
 314         return (p);
 315 lose:
 316         *p = c;
 317         return (startp);
 318 }
 319
 320
 321 STATIC void
 322 removerecordregions(int endoff)
 323 {
 324         if (ifslastp == NULL)
 325                 return;
 326
 327         if (ifsfirst.endoff > endoff) {
 328                 while (ifsfirst.next != NULL) {
 329                         struct ifsregion *ifsp;
 330                         INTOFF;
 331                         ifsp = ifsfirst.next->next;
 332                         ckfree(ifsfirst.next);
 333                         ifsfirst.next = ifsp;
 334                         INTON;
 335                 }
 336                 if (ifsfirst.begoff > endoff)
 337                         ifslastp = NULL;
 338                 else {
 339                         ifslastp = &ifsfirst;
 340                         ifsfirst.endoff = endoff;
 341                 }
 342                 return;
 343         }
 344
 345         ifslastp = &ifsfirst;
 346         while (ifslastp->next && ifslastp->next->begoff < endoff)
 347                 ifslastp=ifslastp->next;
 348         while (ifslastp->next != NULL) {
 349                 struct ifsregion *ifsp;
 350                 INTOFF;
 351                 ifsp = ifslastp->next->next;
 352                 ckfree(ifslastp->next);
 353                 ifslastp->next = ifsp;
 354                 INTON;
 355         }
 356         if (ifslastp->endoff > endoff)
 357                 ifslastp->endoff = endoff;
 358 }
 359
 360 /*
 361  * Expand arithmetic expression.  Backup to start of expression,
 362  * evaluate, place result in (backed up) result, adjust string position.
 363  */
 364 void
 365 expari(int flag)
 366 {
 367         char *p, *start;
 368         int result;
 369         int begoff;
 370         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 371         int quoted;
 372
 373
 374         /*
 375          * This routine is slightly over-complicated for
 376          * efficiency.  First we make sure there is
 377          * enough space for the result, which may be bigger
 378          * than the expression if we add exponentiation.  Next we
 379          * scan backwards looking for the start of arithmetic.  If the
 380          * next previous character is a CTLESC character, then we
 381          * have to rescan starting from the beginning since CTLESC
 382          * characters have to be processed left to right.
 383          */
 384 #if INT_MAX / 1000000000 >= 10 || INT_MIN / 1000000000 <= -10
 385 #error "integers with more than 10 digits are not supported"
 386 #endif
 387         CHECKSTRSPACE(12 - 2, expdest);
 388         USTPUTC('\0', expdest);
 389         start = stackblock();
 390         p = expdest - 2;
 391         while (p >= start && *p != CTLARI)
 392                 --p;
 393         if (p < start || *p != CTLARI)
 394                 error("missing CTLARI (shouldn't happen)");
 395         if (p > start && *(p - 1) == CTLESC)
 396                 for (p = start; *p != CTLARI; p++)
 397                         if (*p == CTLESC)
 398                                 p++;
 399
 400         if (p[1] == '"')
 401                 quoted=1;
 402         else
 403                 quoted=0;
 404         begoff = p - start;
 405         removerecordregions(begoff);
 406         if (quotes)
 407                 rmescapes(p+2);
 408         result = arith(p+2);
 409         fmtstr(p, 12, "%d", result);
 410         while (*p++)
 411                 ;
 412         if (quoted == 0)
 413                 recordregion(begoff, p - 1 - start, 0);
 414         result = expdest - p + 1;
 415         STADJUST(-result, expdest);
 416 }
 417
 418
 419 /*
 420  * Expand stuff in backwards quotes.
 421  */
 422
 423 STATIC void
 424 expbackq(union node *cmd, int quoted, int flag)
 425 {
 426         struct backcmd in;
 427         int i;
 428         char buf[128];
 429         char *p;
 430         char *dest = expdest;
 431         struct ifsregion saveifs, *savelastp;
 432         struct nodelist *saveargbackq;
 433         char lastc;
 434         int startloc = dest - stackblock();
 435         char const *syntax = quoted? DQSYNTAX : BASESYNTAX;
 436         int saveherefd;
 437         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 438
 439         INTOFF;
 440         saveifs = ifsfirst;
 441         savelastp = ifslastp;
 442         saveargbackq = argbackq;
 443         saveherefd = herefd;
 444         herefd = -1;
 445         p = grabstackstr(dest);
 446         evalbackcmd(cmd, &in);
 447         ungrabstackstr(p, dest);
 448         ifsfirst = saveifs;
 449         ifslastp = savelastp;
 450         argbackq = saveargbackq;
 451         herefd = saveherefd;
 452
 453         p = in.buf;
 454         lastc = '\0';
 455         for (;;) {
 456                 if (--in.nleft < 0) {
 457                         if (in.fd < 0)
 458                                 break;
 459                         while ((i = read(in.fd, buf, sizeof buf)) < 0 && errno == EINTR);
 460                         TRACE(("expbackq: read returns %d\n", i));
 461                         if (i <= 0)
 462                                 break;
 463                         p = buf;
 464                         in.nleft = i - 1;
 465                 }
 466                 lastc = *p++;
 467                 if (lastc != '\0') {
 468                         if (quotes && syntax[(int)lastc] == CCTL)
 469                                 STPUTC(CTLESC, dest);
 470                         STPUTC(lastc, dest);
 471                 }
 472         }
 473
 474         /* Eat all trailing newlines */
 475         for ( ; (dest - stackblock()) > startloc && *(dest-1) == '\n'; )
 476                 STUNPUTC(dest);
 477
 478         if (in.fd >= 0)
 479                 close(in.fd);
 480         if (in.buf)
 481                 ckfree(in.buf);
 482         if (in.jp)
 483                 exitstatus = waitforjob(in.jp, (int *)NULL);
 484         if (quoted == 0)
 485                 recordregion(startloc, dest - stackblock(), 0);
 486         TRACE(("evalbackq: size=%d: \"%.*s\"\n",
 487                 (dest - stackblock()) - startloc,
 488                 (dest - stackblock()) - startloc,
 489                 stackblock() + startloc));
 490         expdest = dest;
 491         INTON;
 492 }
 493
 494
 495
 496 STATIC int
 497 subevalvar(char *p, char *str, int strloc, int subtype, int startloc,
 498   int varflags)
 499 {
 500         char *startp;
 501         char *loc = NULL;
 502         char *q;
 503         int c = 0;
 504         int saveherefd = herefd;
 505         struct nodelist *saveargbackq = argbackq;
 506         int amount;
 507
 508         herefd = -1;
 509         argstr(p, 0);
 510         STACKSTRNUL(expdest);
 511         herefd = saveherefd;
 512         argbackq = saveargbackq;
 513         startp = stackblock() + startloc;
 514         if (str == NULL)
 515             str = stackblock() + strloc;
 516
 517         switch (subtype) {
 518         case VSASSIGN:
 519                 setvar(str, startp, 0);
 520                 amount = startp - expdest;
 521                 STADJUST(amount, expdest);
 522                 varflags &= ~VSNUL;
 523                 if (c != 0)
 524                         *loc = c;
 525                 return 1;
 526
 527         case VSQUESTION:
 528                 if (*p != CTLENDVAR) {
 529                         outfmt(&errout, "%s\n", startp);
 530                         error((char *)NULL);
 531                 }
 532                 error("%.*s: parameter %snot set", p - str - 1,
 533                       str, (varflags & VSNUL) ? "null or "
 534                                               : nullstr);
 535                 return 0;
 536
 537         case VSTRIMLEFT:
 538                 for (loc = startp; loc < str; loc++) {
 539                         c = *loc;
 540                         *loc = '\0';
 541                         if (patmatch(str, startp, varflags & VSQUOTE)) {
 542                                 *loc = c;
 543                                 goto recordleft;
 544                         }
 545                         *loc = c;
 546                         if ((varflags & VSQUOTE) && *loc == CTLESC)
 547                                 loc++;
 548                 }
 549                 return 0;
 550
 551         case VSTRIMLEFTMAX:
 552                 for (loc = str - 1; loc >= startp;) {
 553                         c = *loc;
 554                         *loc = '\0';
 555                         if (patmatch(str, startp, varflags & VSQUOTE)) {
 556                                 *loc = c;
 557                                 goto recordleft;
 558                         }
 559                         *loc = c;
 560                         loc--;
 561                         if ((varflags & VSQUOTE) && loc > startp &&
 562                             *(loc - 1) == CTLESC) {
 563                                 for (q = startp; q < loc; q++)
 564                                         if (*q == CTLESC)
 565                                                 q++;
 566                                 if (q > loc)
 567                                         loc--;
 568                         }
 569                 }
 570                 return 0;
 571
 572         case VSTRIMRIGHT:
 573                 for (loc = str - 1; loc >= startp;) {
 574                         if (patmatch(str, loc, varflags & VSQUOTE)) {
 575                                 amount = loc - expdest;
 576                                 STADJUST(amount, expdest);
 577                                 return 1;
 578                         }
 579                         loc--;
 580                         if ((varflags & VSQUOTE) && loc > startp &&
 581                             *(loc - 1) == CTLESC) {
 582                                 for (q = startp; q < loc; q++)
 583                                         if (*q == CTLESC)
 584                                                 q++;
 585                                 if (q > loc)
 586                                         loc--;
 587                         }
 588                 }
 589                 return 0;
 590
 591         case VSTRIMRIGHTMAX:
 592                 for (loc = startp; loc < str - 1; loc++) {
 593                         if (patmatch(str, loc, varflags & VSQUOTE)) {
 594                                 amount = loc - expdest;
 595                                 STADJUST(amount, expdest);
 596                                 return 1;
 597                         }
 598                         if ((varflags & VSQUOTE) && *loc == CTLESC)
 599                                 loc++;
 600                 }
 601                 return 0;
 602
 603
 604         default:
 605                 abort();
 606         }
 607
 608 recordleft:
 609         amount = ((str - 1) - (loc - startp)) - expdest;
 610         STADJUST(amount, expdest);
 611         while (loc != str - 1)
 612                 *startp++ = *loc++;
 613         return 1;
 614 }
 615
 616
 617 /*
 618  * Expand a variable, and return a pointer to the next character in the
 619  * input string.
 620  */
 621
 622 STATIC char *
 623 evalvar(char *p, int flag)
 624 {
 625         int subtype;
 626         int varflags;
 627         char *var;
 628         char *val;
 629         int patloc;
 630         int c;
 631         int set;
 632         int special;
 633         int startloc;
 634         int varlen;
 635         int easy;
 636         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 637
 638         varflags = *p++;
 639         subtype = varflags & VSTYPE;
 640         var = p;
 641         special = 0;
 642         if (! is_name(*p))
 643                 special = 1;
 644         p = strchr(p, '=') + 1;
 645 again: /* jump here after setting a variable with ${var=text} */
 646         if (special) {
 647                 set = varisset(var, varflags & VSNUL);
 648                 val = NULL;
 649         } else {
 650                 val = bltinlookup(var, 1);
 651                 if (val == NULL || ((varflags & VSNUL) && val[0] == '\0')) {
 652                         val = NULL;
 653                         set = 0;
 654                 } else
 655                         set = 1;
 656         }
 657         varlen = 0;
 658         startloc = expdest - stackblock();
 659         if (!set && uflag) {
 660                 switch (subtype) {
 661                 case VSNORMAL:
 662                 case VSTRIMLEFT:
 663                 case VSTRIMLEFTMAX:
 664                 case VSTRIMRIGHT:
 665                 case VSTRIMRIGHTMAX:
 666                 case VSLENGTH:
 667                         error("%.*s: parameter not set", p - var - 1, var);
 668                 }
 669         }
 670         if (set && subtype != VSPLUS) {
 671                 /* insert the value of the variable */
 672                 if (special) {
 673                         varvalue(var, varflags & VSQUOTE, flag & EXP_FULL);
 674                         if (subtype == VSLENGTH) {
 675                                 varlen = expdest - stackblock() - startloc;
 676                                 STADJUST(-varlen, expdest);
 677                         }
 678                 } else {
 679                         char const *syntax = (varflags & VSQUOTE) ? DQSYNTAX
 680                                                                   : BASESYNTAX;
 681
 682                         if (subtype == VSLENGTH) {
 683                                 for (;*val; val++)
 684                                         varlen++;
 685                         }
 686                         else {
 687                                 while (*val) {
 688                                         if (quotes &&
 689                                             syntax[(int)*val] == CCTL)
 690                                                 STPUTC(CTLESC, expdest);
 691                                         STPUTC(*val++, expdest);
 692                                 }
 693
 694                         }
 695                 }
 696         }
 697
 698         if (subtype == VSPLUS)
 699                 set = ! set;
 700
 701         easy = ((varflags & VSQUOTE) == 0 ||
 702                 (*var == '@' && shellparam.nparam != 1));
 703
 704
 705         switch (subtype) {
 706         case VSLENGTH:
 707                 expdest = cvtnum(varlen, expdest);
 708                 goto record;
 709
 710         case VSNORMAL:
 711                 if (!easy)
 712                         break;
 713 record:
 714                 recordregion(startloc, expdest - stackblock(),
 715                              varflags & VSQUOTE);
 716                 break;
 717
 718         case VSPLUS:
 719         case VSMINUS:
 720                 if (!set) {
 721                         argstr(p, flag);
 722                         break;
 723                 }
 724                 if (easy)
 725                         goto record;
 726                 break;
 727
 728         case VSTRIMLEFT:
 729         case VSTRIMLEFTMAX:
 730         case VSTRIMRIGHT:
 731         case VSTRIMRIGHTMAX:
 732                 if (!set)
 733                         break;
 734                 /*
 735                  * Terminate the string and start recording the pattern
 736                  * right after it
 737                  */
 738                 STPUTC('\0', expdest);
 739                 patloc = expdest - stackblock();
 740                 if (subevalvar(p, NULL, patloc, subtype,
 741                                startloc, varflags) == 0) {
 742                         int amount = (expdest - stackblock() - patloc) + 1;
 743                         STADJUST(-amount, expdest);
 744                 }
 745                 /* Remove any recorded regions beyond start of variable */
 746                 removerecordregions(startloc);
 747                 goto record;
 748
 749         case VSASSIGN:
 750         case VSQUESTION:
 751                 if (!set) {
 752                         if (subevalvar(p, var, 0, subtype, startloc, varflags)) {
 753                                 varflags &= ~VSNUL;
 754                                 /*
 755                                  * Remove any recorded regions beyond
 756                                  * start of variable
 757                                  */
 758                                 removerecordregions(startloc);
 759                                 goto again;
 760                         }
 761                         break;
 762                 }
 763                 if (easy)
 764                         goto record;
 765                 break;
 766
 767         default:
 768                 abort();
 769         }
 770
 771         if (subtype != VSNORMAL) {      /* skip to end of alternative */
 772                 int nesting = 1;
 773                 for (;;) {
 774                         if ((c = *p++) == CTLESC)
 775                                 p++;
 776                         else if (c == CTLBACKQ || c == (CTLBACKQ|CTLQUOTE)) {
 777                                 if (set)
 778                                         argbackq = argbackq->next;
 779                         } else if (c == CTLVAR) {
 780                                 if ((*p++ & VSTYPE) != VSNORMAL)
 781                                         nesting++;
 782                         } else if (c == CTLENDVAR) {
 783                                 if (--nesting == 0)
 784                                         break;
 785                         }
 786                 }
 787         }
 788         return p;
 789 }
 790
 791
 792
 793 /*
 794  * Test whether a specialized variable is set.
 795  */
 796
 797 STATIC int
 798 varisset(char *name, int nulok)
 799 {
 800
 801         if (*name == '!')
 802                 return backgndpid != -1;
 803         else if (*name == '@' || *name == '*') {
 804                 if (*shellparam.p == NULL)
 805                         return 0;
 806
 807                 if (nulok) {
 808                         char **av;
 809
 810                         for (av = shellparam.p; *av; av++)
 811                                 if (**av != '\0')
 812                                         return 1;
 813                         return 0;
 814                 }
 815         } else if (is_digit(*name)) {
 816                 char *ap;
 817                 int num = atoi(name);
 818
 819                 if (num > shellparam.nparam)
 820                         return 0;
 821
 822                 if (num == 0)
 823                         ap = arg0;
 824                 else
 825                         ap = shellparam.p[num - 1];
 826
 827                 if (nulok && (ap == NULL || *ap == '\0'))
 828                         return 0;
 829         }
 830         return 1;
 831 }
 832
 833
 834
 835 /*
 836  * Add the value of a specialized variable to the stack string.
 837  */
 838
 839 STATIC void
 840 varvalue(char *name, int quoted, int allow_split)
 841 {
 842         int num;
 843         char *p;
 844         int i;
 845         char sep;
 846         char **ap;
 847         char const *syntax;
 848
 849 #define STRTODEST(p) \
 850         do {\
 851         if (allow_split) { \
 852                 syntax = quoted? DQSYNTAX : BASESYNTAX; \
 853                 while (*p) { \
 854                         if (syntax[(int)*p] == CCTL) \
 855                                 STPUTC(CTLESC, expdest); \
 856                         STPUTC(*p++, expdest); \
 857                 } \
 858         } else \
 859                 while (*p) \
 860                         STPUTC(*p++, expdest); \
 861         } while (0)
 862
 863
 864         switch (*name) {
 865         case '$':
 866                 num = rootpid;
 867                 goto numvar;
 868         case '?':
 869                 num = oexitstatus;
 870                 goto numvar;
 871         case '#':
 872                 num = shellparam.nparam;
 873                 goto numvar;
 874         case '!':
 875                 num = backgndpid;
 876 numvar:
 877                 expdest = cvtnum(num, expdest);
 878                 break;
 879         case '-':
 880                 for (i = 0 ; i < NOPTS ; i++) {
 881                         if (optlist[i].val)
 882                                 STPUTC(optlist[i].letter, expdest);
 883                 }
 884                 break;
 885         case '@':
 886                 if (allow_split && quoted) {
 887                         for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
 888                                 STRTODEST(p);
 889                                 if (*ap)
 890                                         STPUTC('\0', expdest);
 891                         }
 892                         break;
 893                 }
 894                 /* fall through */
 895         case '*':
 896                 if (ifsset() != 0)
 897                         sep = ifsval()[0];
 898                 else
 899                         sep = ' ';
 900                 for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
 901                         STRTODEST(p);
 902                         if (*ap && sep)
 903                                 STPUTC(sep, expdest);
 904                 }
 905                 break;
 906         case '0':
 907                 p = arg0;
 908                 STRTODEST(p);
 909                 break;
 910         default:
 911                 if (is_digit(*name)) {
 912                         num = atoi(name);
 913                         if (num > 0 && num <= shellparam.nparam) {
 914                                 p = shellparam.p[num - 1];
 915                                 STRTODEST(p);
 916                         }
 917                 }
 918                 break;
 919         }
 920 }
 921
 922
 923
 924 /*
 925  * Record the the fact that we have to scan this region of the
 926  * string for IFS characters.
 927  */
 928
 929 STATIC void
 930 recordregion(int start, int end, int nulonly)
 931 {
 932         struct ifsregion *ifsp;
 933
 934         if (ifslastp == NULL) {
 935                 ifsp = &ifsfirst;
 936         } else {
 937                 ifsp = (struct ifsregion *)ckmalloc(sizeof (struct ifsregion));
 938                 ifslastp->next = ifsp;
 939         }
 940         ifslastp = ifsp;
 941         ifslastp->next = NULL;
 942         ifslastp->begoff = start;
 943         ifslastp->endoff = end;
 944         ifslastp->nulonly = nulonly;
 945 }
 946
 947
 948
 949 /*
 950  * Break the argument string into pieces based upon IFS and add the
 951  * strings to the argument list.  The regions of the string to be
 952  * searched for IFS characters have been stored by recordregion.
 953  */
 954 STATIC void
 955 ifsbreakup(char *string, struct arglist *arglist)
 956 {
 957         struct ifsregion *ifsp;
 958         struct strlist *sp;
 959         char *start;
 960         char *p;
 961         char *q;
 962         const char *ifs;
 963         int ifsspc;
 964         int nulonly;
 965
 966
 967         start = string;
 968         ifsspc = 0;
 969         nulonly = 0;
 970         if (ifslastp != NULL) {
 971                 ifsp = &ifsfirst;
 972                 do {
 973                         p = string + ifsp->begoff;
 974                         nulonly = ifsp->nulonly;
 975                         ifs = nulonly ? nullstr :
 976                                 ( ifsset() ? ifsval() : " \t\n" );
 977                         ifsspc = 0;
 978                         while (p < string + ifsp->endoff) {
 979                                 q = p;
 980                                 if (*p == CTLESC)
 981                                         p++;
 982                                 if (strchr(ifs, *p)) {
 983                                         if (!nulonly)
 984                                                 ifsspc = (strchr(" \t\n", *p) != NULL);
 985                                         /* Ignore IFS whitespace at start */
 986                                         if (q == start && ifsspc) {
 987                                                 p++;
 988                                                 start = p;
 989                                                 continue;
 990                                         }
 991                                         *q = '\0';
 992                                         sp = (struct strlist *)stalloc(sizeof *sp);
 993                                         sp->text = start;
 994                                         *arglist->lastp = sp;
 995                                         arglist->lastp = &sp->next;
 996                                         p++;
 997                                         if (!nulonly) {
 998                                                 for (;;) {
 999                                                         if (p >= string + ifsp->endoff) {
1000                                                                 break;
1001                                                         }
1002                                                         q = p;
1003                                                         if (*p == CTLESC)
1004                                                                 p++;
1005                                                         if (strchr(ifs, *p) == NULL ) {
1006                                                                 p = q;
1007                                                                 break;
1008                                                         } else if (strchr(" \t\n",*p) == NULL) {
1009                                                                 if (ifsspc) {
1010                                                                         p++;
1011                                                                         ifsspc = 0;
1012                                                                 } else {
1013                                                                         p = q;
1014                                                                         break;
1015                                                                 }
1016                                                         } else
1017                                                                 p++;
1018                                                 }
1019                                         }
1020                                         start = p;
1021                                 } else
1022                                         p++;
1023                         }
1024                 } while ((ifsp = ifsp->next) != NULL);
1025                 if (*start || (!ifsspc && start > string &&
1026                         (nulonly || 1))) {
1027                         sp = (struct strlist *)stalloc(sizeof *sp);
1028                         sp->text = start;
1029                         *arglist->lastp = sp;
1030                         arglist->lastp = &sp->next;
1031                 }
1032         } else {
1033                 sp = (struct strlist *)stalloc(sizeof *sp);
1034                 sp->text = start;
1035                 *arglist->lastp = sp;
1036                 arglist->lastp = &sp->next;
1037         }
1038 }
1039
1040
1041
1042 /*
1043  * Expand shell metacharacters.  At this point, the only control characters
1044  * should be escapes.  The results are stored in the list exparg.
1045  */
1046
1047 STATIC char *expdir;
1048
1049
1050 STATIC void
1051 expandmeta(struct strlist *str, int flag __unused)
1052 {
1053         char *p;
1054         struct strlist **savelastp;
1055         struct strlist *sp;
1056         char c;
1057         /* TODO - EXP_REDIR */
1058
1059         while (str) {
1060                 if (fflag)
1061                         goto nometa;
1062                 p = str->text;
1063                 for (;;) {                      /* fast check for meta chars */
1064                         if ((c = *p++) == '\0')
1065                                 goto nometa;
1066                         if (c == '*' || c == '?' || c == '[' || c == '!')
1067                                 break;
1068                 }
1069                 savelastp = exparg.lastp;
1070                 INTOFF;
1071                 if (expdir == NULL) {
1072                         int i = strlen(str->text);
1073                         expdir = ckmalloc(i < 2048 ? 2048 : i); /* XXX */
1074                 }
1075
1076                 expmeta(expdir, str->text);
1077                 ckfree(expdir);
1078                 expdir = NULL;
1079                 INTON;
1080                 if (exparg.lastp == savelastp) {
1081                         /*
1082                          * no matches
1083                          */
1084 nometa:
1085                         *exparg.lastp = str;
1086                         rmescapes(str->text);
1087                         exparg.lastp = &str->next;
1088                 } else {
1089                         *exparg.lastp = NULL;
1090                         *savelastp = sp = expsort(*savelastp);
1091                         while (sp->next != NULL)
1092                                 sp = sp->next;
1093                         exparg.lastp = &sp->next;
1094                 }
1095                 str = str->next;
1096         }
1097 }
1098
1099
1100 /*
1101  * Do metacharacter (i.e. *, ?, [...]) expansion.
1102  */
1103
1104 STATIC void
1105 expmeta(char *enddir, char *name)
1106 {
1107         char *p;
1108         const 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 || lstat(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                 q = ".";
1182         } else if (enddir == expdir + 1 && *expdir == '/') {
1183                 q = "/";
1184         } else {
1185                 q = expdir;
1186                 enddir[-1] = '\0';
1187         }
1188         if ((dirp = opendir(q)) == 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, 0)) {
1210                         if (atend) {
1211                                 scopy(dp->d_name, enddir);
1212                                 addfname(expdir);
1213                         } else {
1214                                 char *t;
1215                                 for (t = enddir, q = dp->d_name;
1216                                      (*t++ = *q++) != '\0';)
1217                                         continue;
1218                                 t[-1] = '/';
1219                                 expmeta(t, 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(char *name)
1235 {
1236         char *p;
1237         struct strlist *sp;
1238
1239         p = stalloc(strlen(name) + 1);
1240         scopy(name, p);
1241         sp = (struct strlist *)stalloc(sizeof *sp);
1242         sp->text = p;
1243         *exparg.lastp = sp;
1244         exparg.lastp = &sp->next;
1245 }
1246
1247
1248 /*
1249  * Sort the results of file name expansion.  It calculates the number of
1250  * strings to sort and then calls msort (short for merge sort) to do the
1251  * work.
1252  */
1253
1254 STATIC struct strlist *
1255 expsort(struct strlist *str)
1256 {
1257         int len;
1258         struct strlist *sp;
1259
1260         len = 0;
1261         for (sp = str ; sp ; sp = sp->next)
1262                 len++;
1263         return msort(str, len);
1264 }
1265
1266
1267 STATIC struct strlist *
1268 msort(struct strlist *list, int len)
1269 {
1270         struct strlist *p, *q = NULL;
1271         struct strlist **lpp;
1272         int half;
1273         int n;
1274
1275         if (len <= 1)
1276                 return list;
1277         half = len >> 1;
1278         p = list;
1279         for (n = half ; --n >= 0 ; ) {
1280                 q = p;
1281                 p = p->next;
1282         }
1283         q->next = NULL;                 /* terminate first half of list */
1284         q = msort(list, half);          /* sort first half of list */
1285         p = msort(p, len - half);               /* sort second half */
1286         lpp = &list;
1287         for (;;) {
1288                 if (strcmp(p->text, q->text) < 0) {
1289                         *lpp = p;
1290                         lpp = &p->next;
1291                         if ((p = *lpp) == NULL) {
1292                                 *lpp = q;
1293                                 break;
1294                         }
1295                 } else {
1296                         *lpp = q;
1297                         lpp = &q->next;
1298                         if ((q = *lpp) == NULL) {
1299                                 *lpp = p;
1300                                 break;
1301                         }
1302                 }
1303         }
1304         return list;
1305 }
1306
1307
1308
1309 /*
1310  * Returns true if the pattern matches the string.
1311  */
1312
1313 int
1314 patmatch(char *pattern, char *string, int squoted)
1315 {
1316 #ifdef notdef
1317         if (pattern[0] == '!' && pattern[1] == '!')
1318                 return 1 - pmatch(pattern + 2, string);
1319         else
1320 #endif
1321                 return pmatch(pattern, string, squoted);
1322 }
1323
1324
1325 STATIC int
1326 pmatch(char *pattern, char *string, int squoted)
1327 {
1328         char *p, *q;
1329         char c;
1330
1331         p = pattern;
1332         q = string;
1333         for (;;) {
1334                 switch (c = *p++) {
1335                 case '\0':
1336                         goto breakloop;
1337                 case CTLESC:
1338                         if (squoted && *q == CTLESC)
1339                                 q++;
1340                         if (*q++ != *p++)
1341                                 return 0;
1342                         break;
1343                 case CTLQUOTEMARK:
1344                         continue;
1345                 case '?':
1346                         if (squoted && *q == CTLESC)
1347                                 q++;
1348                         if (*q++ == '\0')
1349                                 return 0;
1350                         break;
1351                 case '*':
1352                         c = *p;
1353                         while (c == CTLQUOTEMARK || c == '*')
1354                                 c = *++p;
1355                         if (c != CTLESC &&  c != CTLQUOTEMARK &&
1356                             c != '?' && c != '*' && c != '[') {
1357                                 while (*q != c) {
1358                                         if (squoted && *q == CTLESC &&
1359                                             q[1] == c)
1360                                                 break;
1361                                         if (*q == '\0')
1362                                                 return 0;
1363                                         if (squoted && *q == CTLESC)
1364                                                 q++;
1365                                         q++;
1366                                 }
1367                         }
1368                         do {
1369                                 if (pmatch(p, q, squoted))
1370                                         return 1;
1371                                 if (squoted && *q == CTLESC)
1372                                         q++;
1373                         } while (*q++ != '\0');
1374                         return 0;
1375                 case '[': {
1376                         char *endp;
1377                         int invert, found;
1378                         char chr;
1379
1380                         endp = p;
1381                         if (*endp == '!' || *endp == '^')
1382                                 endp++;
1383                         for (;;) {
1384                                 while (*endp == CTLQUOTEMARK)
1385                                         endp++;
1386                                 if (*endp == '\0')
1387                                         goto dft;               /* no matching ] */
1388                                 if (*endp == CTLESC)
1389                                         endp++;
1390                                 if (*++endp == ']')
1391                                         break;
1392                         }
1393                         invert = 0;
1394                         if (*p == '!' || *p == '^') {
1395                                 invert++;
1396                                 p++;
1397                         }
1398                         found = 0;
1399                         chr = *q++;
1400                         if (squoted && chr == CTLESC)
1401                                 chr = *q++;
1402                         if (chr == '\0')
1403                                 return 0;
1404                         c = *p++;
1405                         do {
1406                                 if (c == CTLQUOTEMARK)
1407                                         continue;
1408                                 if (c == CTLESC)
1409                                         c = *p++;
1410                                 if (*p == '-' && p[1] != ']') {
1411                                         p++;
1412                                         while (*p == CTLQUOTEMARK)
1413                                                 p++;
1414                                         if (*p == CTLESC)
1415                                                 p++;
1416                                         if (   collate_range_cmp(chr, c) >= 0
1417                                             && collate_range_cmp(chr, *p) <= 0
1418                                            )
1419                                                 found = 1;
1420                                         p++;
1421                                 } else {
1422                                         if (chr == c)
1423                                                 found = 1;
1424                                 }
1425                         } while ((c = *p++) != ']');
1426                         if (found == invert)
1427                                 return 0;
1428                         break;
1429                 }
1430 dft:            default:
1431                         if (squoted && *q == CTLESC)
1432                                 q++;
1433                         if (*q++ != c)
1434                                 return 0;
1435                         break;
1436                 }
1437         }
1438 breakloop:
1439         if (*q != '\0')
1440                 return 0;
1441         return 1;
1442 }
1443
1444
1445
1446 /*
1447  * Remove any CTLESC characters from a string.
1448  */
1449
1450 void
1451 rmescapes(char *str)
1452 {
1453         char *p, *q;
1454
1455         p = str;
1456         while (*p != CTLESC && *p != CTLQUOTEMARK) {
1457                 if (*p++ == '\0')
1458                         return;
1459         }
1460         q = p;
1461         while (*p) {
1462                 if (*p == CTLQUOTEMARK) {
1463                         p++;
1464                         continue;
1465                 }
1466                 if (*p == CTLESC)
1467                         p++;
1468                 *q++ = *p++;
1469         }
1470         *q = '\0';
1471 }
1472
1473
1474
1475 /*
1476  * See if a pattern matches in a case statement.
1477  */
1478
1479 int
1480 casematch(union node *pattern, char *val)
1481 {
1482         struct stackmark smark;
1483         int result;
1484         char *p;
1485
1486         setstackmark(&smark);
1487         argbackq = pattern->narg.backquote;
1488         STARTSTACKSTR(expdest);
1489         ifslastp = NULL;
1490         argstr(pattern->narg.text, EXP_TILDE | EXP_CASE);
1491         STPUTC('\0', expdest);
1492         p = grabstackstr(expdest);
1493         result = patmatch(p, val, 0);
1494         popstackmark(&smark);
1495         return result;
1496 }
1497
1498 /*
1499  * Our own itoa().
1500  */
1501
1502 STATIC char *
1503 cvtnum(int num, char *buf)
1504 {
1505         char temp[32];
1506         int neg = num < 0;
1507         char *p = temp + 31;
1508
1509         temp[31] = '\0';
1510
1511         do {
1512                 *--p = num % 10 + '0';
1513         } while ((num /= 10) != 0);
1514
1515         if (neg)
1516                 *--p = '-';
1517
1518         while (*p)
1519                 STPUTC(*p++, buf);
1520         return buf;
1521 }
1522
1523 /*
1524  * Do most of the work for wordexp(3).
1525  */
1526
1527 int
1528 wordexpcmd(int argc, char **argv)
1529 {
1530         size_t len;
1531         int i;
1532
1533         out1fmt("%08x", argc - 1);
1534         for (i = 1, len = 0; i < argc; i++)
1535                 len += strlen(argv[i]);
1536         out1fmt("%08x", (int)len);
1537         for (i = 1; i < argc; i++) {
1538                 out1str(argv[i]);
1539                 out1c('\0');
1540         }
1541         return (0);
1542 }