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 1.5 2004/03/19 18:39:41 cpressey 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 /*
 131  * Expand shell variables and backquotes inside a here document.
 132  *      union node *arg         the document
 133  *      int fd;                 where to write the expanded version
 134  */
 135
 136 void
 137 expandhere(union node *arg, int fd)
 138 {
 139         herefd = fd;
 140         expandarg(arg, (struct arglist *)NULL, 0);
 141         xwrite(fd, stackblock(), expdest - stackblock());
 142 }
 143
 144
 145 /*
 146  * Perform variable substitution and command substitution on an argument,
 147  * placing the resulting list of arguments in arglist.  If EXP_FULL is true,
 148  * perform splitting and file name expansion.  When arglist is NULL, perform
 149  * here document expansion.
 150  */
 151
 152 void
 153 expandarg(union node *arg, struct arglist *arglist, int flag)
 154 {
 155         struct strlist *sp;
 156         char *p;
 157
 158         argbackq = arg->narg.backquote;
 159         STARTSTACKSTR(expdest);
 160         ifsfirst.next = NULL;
 161         ifslastp = NULL;
 162         argstr(arg->narg.text, flag);
 163         if (arglist == NULL) {
 164                 return;                 /* here document expanded */
 165         }
 166         STPUTC('\0', expdest);
 167         p = grabstackstr(expdest);
 168         exparg.lastp = &exparg.list;
 169         /*
 170          * TODO - EXP_REDIR
 171          */
 172         if (flag & EXP_FULL) {
 173                 ifsbreakup(p, &exparg);
 174                 *exparg.lastp = NULL;
 175                 exparg.lastp = &exparg.list;
 176                 expandmeta(exparg.list, flag);
 177         } else {
 178                 if (flag & EXP_REDIR) /*XXX - for now, just remove escapes */
 179                         rmescapes(p);
 180                 sp = (struct strlist *)stalloc(sizeof (struct strlist));
 181                 sp->text = p;
 182                 *exparg.lastp = sp;
 183                 exparg.lastp = &sp->next;
 184         }
 185         while (ifsfirst.next != NULL) {
 186                 struct ifsregion *ifsp;
 187                 INTOFF;
 188                 ifsp = ifsfirst.next->next;
 189                 ckfree(ifsfirst.next);
 190                 ifsfirst.next = ifsp;
 191                 INTON;
 192         }
 193         *exparg.lastp = NULL;
 194         if (exparg.list) {
 195                 *arglist->lastp = exparg.list;
 196                 arglist->lastp = exparg.lastp;
 197         }
 198 }
 199
 200
 201
 202 /*
 203  * Perform variable and command substitution.  If EXP_FULL is set, output CTLESC
 204  * characters to allow for further processing.  Otherwise treat
 205  * $@ like $* since no splitting will be performed.
 206  */
 207
 208 STATIC void
 209 argstr(char *p, int flag)
 210 {
 211         char c;
 212         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);  /* do CTLESC */
 213         int firsteq = 1;
 214
 215         if (*p == '~' && (flag & (EXP_TILDE | EXP_VARTILDE)))
 216                 p = exptilde(p, flag);
 217         for (;;) {
 218                 switch (c = *p++) {
 219                 case '\0':
 220                 case CTLENDVAR: /* ??? */
 221                         goto breakloop;
 222                 case CTLQUOTEMARK:
 223                         /* "$@" syntax adherence hack */
 224                         if (p[0] == CTLVAR && p[2] == '@' && p[3] == '=')
 225                                 break;
 226                         if ((flag & EXP_FULL) != 0)
 227                                 STPUTC(c, expdest);
 228                         break;
 229                 case CTLESC:
 230                         if (quotes)
 231                                 STPUTC(c, expdest);
 232                         c = *p++;
 233                         STPUTC(c, expdest);
 234                         break;
 235                 case CTLVAR:
 236                         p = evalvar(p, flag);
 237                         break;
 238                 case CTLBACKQ:
 239                 case CTLBACKQ|CTLQUOTE:
 240                         expbackq(argbackq->n, c & CTLQUOTE, flag);
 241                         argbackq = argbackq->next;
 242                         break;
 243                 case CTLENDARI:
 244                         expari(flag);
 245                         break;
 246                 case ':':
 247                 case '=':
 248                         /*
 249                          * sort of a hack - expand tildes in variable
 250                          * assignments (after the first '=' and after ':'s).
 251                          */
 252                         STPUTC(c, expdest);
 253                         if (flag & EXP_VARTILDE && *p == '~') {
 254                                 if (c == '=') {
 255                                         if (firsteq)
 256                                                 firsteq = 0;
 257                                         else
 258                                                 break;
 259                                 }
 260                                 p = exptilde(p, flag);
 261                         }
 262                         break;
 263                 default:
 264                         STPUTC(c, expdest);
 265                 }
 266         }
 267 breakloop:;
 268 }
 269
 270 STATIC char *
 271 exptilde(char *p, int flag)
 272 {
 273         char c, *startp = p;
 274         struct passwd *pw;
 275         char *home;
 276         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 277
 278         while ((c = *p) != '\0') {
 279                 switch(c) {
 280                 case CTLESC:
 281                         return (startp);
 282                 case CTLQUOTEMARK:
 283                         return (startp);
 284                 case ':':
 285                         if (flag & EXP_VARTILDE)
 286                                 goto done;
 287                         break;
 288                 case '/':
 289                         goto done;
 290                 }
 291                 p++;
 292         }
 293 done:
 294         *p = '\0';
 295         if (*(startp+1) == '\0') {
 296                 if ((home = lookupvar("HOME")) == NULL)
 297                         goto lose;
 298         } else {
 299                 if ((pw = getpwnam(startp+1)) == NULL)
 300                         goto lose;
 301                 home = pw->pw_dir;
 302         }
 303         if (*home == '\0')
 304                 goto lose;
 305         *p = c;
 306         while ((c = *home++) != '\0') {
 307                 if (quotes && SQSYNTAX[(int)c] == CCTL)
 308                         STPUTC(CTLESC, expdest);
 309                 STPUTC(c, expdest);
 310         }
 311         return (p);
 312 lose:
 313         *p = c;
 314         return (startp);
 315 }
 316
 317
 318 STATIC void
 319 removerecordregions(int endoff)
 320 {
 321         if (ifslastp == NULL)
 322                 return;
 323
 324         if (ifsfirst.endoff > endoff) {
 325                 while (ifsfirst.next != NULL) {
 326                         struct ifsregion *ifsp;
 327                         INTOFF;
 328                         ifsp = ifsfirst.next->next;
 329                         ckfree(ifsfirst.next);
 330                         ifsfirst.next = ifsp;
 331                         INTON;
 332                 }
 333                 if (ifsfirst.begoff > endoff)
 334                         ifslastp = NULL;
 335                 else {
 336                         ifslastp = &ifsfirst;
 337                         ifsfirst.endoff = endoff;
 338                 }
 339                 return;
 340         }
 341
 342         ifslastp = &ifsfirst;
 343         while (ifslastp->next && ifslastp->next->begoff < endoff)
 344                 ifslastp=ifslastp->next;
 345         while (ifslastp->next != NULL) {
 346                 struct ifsregion *ifsp;
 347                 INTOFF;
 348                 ifsp = ifslastp->next->next;
 349                 ckfree(ifslastp->next);
 350                 ifslastp->next = ifsp;
 351                 INTON;
 352         }
 353         if (ifslastp->endoff > endoff)
 354                 ifslastp->endoff = endoff;
 355 }
 356
 357 /*
 358  * Expand arithmetic expression.  Backup to start of expression,
 359  * evaluate, place result in (backed up) result, adjust string position.
 360  */
 361 void
 362 expari(int flag)
 363 {
 364         char *p, *start;
 365         int result;
 366         int begoff;
 367         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 368         int quoted;
 369
 370
 371         /*
 372          * This routine is slightly over-complicated for
 373          * efficiency.  First we make sure there is
 374          * enough space for the result, which may be bigger
 375          * than the expression if we add exponentiation.  Next we
 376          * scan backwards looking for the start of arithmetic.  If the
 377          * next previous character is a CTLESC character, then we
 378          * have to rescan starting from the beginning since CTLESC
 379          * characters have to be processed left to right.
 380          */
 381 #if INT_MAX / 1000000000 >= 10 || INT_MIN / 1000000000 <= -10
 382 #error "integers with more than 10 digits are not supported"
 383 #endif
 384         CHECKSTRSPACE(12 - 2, expdest);
 385         USTPUTC('\0', expdest);
 386         start = stackblock();
 387         p = expdest - 2;
 388         while (p >= start && *p != CTLARI)
 389                 --p;
 390         if (p < start || *p != CTLARI)
 391                 error("missing CTLARI (shouldn't happen)");
 392         if (p > start && *(p - 1) == CTLESC)
 393                 for (p = start; *p != CTLARI; p++)
 394                         if (*p == CTLESC)
 395                                 p++;
 396
 397         if (p[1] == '"')
 398                 quoted=1;
 399         else
 400                 quoted=0;
 401         begoff = p - start;
 402         removerecordregions(begoff);
 403         if (quotes)
 404                 rmescapes(p+2);
 405         result = arith(p+2);
 406         fmtstr(p, 12, "%d", result);
 407         while (*p++)
 408                 ;
 409         if (quoted == 0)
 410                 recordregion(begoff, p - 1 - start, 0);
 411         result = expdest - p + 1;
 412         STADJUST(-result, expdest);
 413 }
 414
 415
 416 /*
 417  * Expand stuff in backwards quotes.
 418  */
 419
 420 STATIC void
 421 expbackq(union node *cmd, int quoted, int flag)
 422 {
 423         struct backcmd in;
 424         int i;
 425         char buf[128];
 426         char *p;
 427         char *dest = expdest;
 428         struct ifsregion saveifs, *savelastp;
 429         struct nodelist *saveargbackq;
 430         char lastc;
 431         int startloc = dest - stackblock();
 432         char const *syntax = quoted? DQSYNTAX : BASESYNTAX;
 433         int saveherefd;
 434         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 435
 436         INTOFF;
 437         saveifs = ifsfirst;
 438         savelastp = ifslastp;
 439         saveargbackq = argbackq;
 440         saveherefd = herefd;
 441         herefd = -1;
 442         p = grabstackstr(dest);
 443         evalbackcmd(cmd, &in);
 444         ungrabstackstr(p, dest);
 445         ifsfirst = saveifs;
 446         ifslastp = savelastp;
 447         argbackq = saveargbackq;
 448         herefd = saveherefd;
 449
 450         p = in.buf;
 451         lastc = '\0';
 452         for (;;) {
 453                 if (--in.nleft < 0) {
 454                         if (in.fd < 0)
 455                                 break;
 456                         while ((i = read(in.fd, buf, sizeof buf)) < 0 && errno == EINTR);
 457                         TRACE(("expbackq: read returns %d\n", i));
 458                         if (i <= 0)
 459                                 break;
 460                         p = buf;
 461                         in.nleft = i - 1;
 462                 }
 463                 lastc = *p++;
 464                 if (lastc != '\0') {
 465                         if (quotes && syntax[(int)lastc] == CCTL)
 466                                 STPUTC(CTLESC, dest);
 467                         STPUTC(lastc, dest);
 468                 }
 469         }
 470
 471         /* Eat all trailing newlines */
 472         for ( ; (dest - stackblock()) > startloc && *(dest-1) == '\n'; )
 473                 STUNPUTC(dest);
 474
 475         if (in.fd >= 0)
 476                 close(in.fd);
 477         if (in.buf)
 478                 ckfree(in.buf);
 479         if (in.jp)
 480                 exitstatus = waitforjob(in.jp, (int *)NULL);
 481         if (quoted == 0)
 482                 recordregion(startloc, dest - stackblock(), 0);
 483         TRACE(("evalbackq: size=%d: \"%.*s\"\n",
 484                 (dest - stackblock()) - startloc,
 485                 (dest - stackblock()) - startloc,
 486                 stackblock() + startloc));
 487         expdest = dest;
 488         INTON;
 489 }
 490
 491
 492
 493 STATIC int
 494 subevalvar(char *p, char *str, int strloc, int subtype, int startloc,
 495   int varflags)
 496 {
 497         char *startp;
 498         char *loc = NULL;
 499         char *q;
 500         int c = 0;
 501         int saveherefd = herefd;
 502         struct nodelist *saveargbackq = argbackq;
 503         int amount;
 504
 505         herefd = -1;
 506         argstr(p, 0);
 507         STACKSTRNUL(expdest);
 508         herefd = saveherefd;
 509         argbackq = saveargbackq;
 510         startp = stackblock() + startloc;
 511         if (str == NULL)
 512             str = stackblock() + strloc;
 513
 514         switch (subtype) {
 515         case VSASSIGN:
 516                 setvar(str, startp, 0);
 517                 amount = startp - expdest;
 518                 STADJUST(amount, expdest);
 519                 varflags &= ~VSNUL;
 520                 if (c != 0)
 521                         *loc = c;
 522                 return 1;
 523
 524         case VSQUESTION:
 525                 if (*p != CTLENDVAR) {
 526                         outfmt(&errout, "%s\n", startp);
 527                         error((char *)NULL);
 528                 }
 529                 error("%.*s: parameter %snot set", p - str - 1,
 530                       str, (varflags & VSNUL) ? "null or "
 531                                               : nullstr);
 532                 return 0;
 533
 534         case VSTRIMLEFT:
 535                 for (loc = startp; loc < str; loc++) {
 536                         c = *loc;
 537                         *loc = '\0';
 538                         if (patmatch(str, startp, varflags & VSQUOTE)) {
 539                                 *loc = c;
 540                                 goto recordleft;
 541                         }
 542                         *loc = c;
 543                         if ((varflags & VSQUOTE) && *loc == CTLESC)
 544                                 loc++;
 545                 }
 546                 return 0;
 547
 548         case VSTRIMLEFTMAX:
 549                 for (loc = str - 1; loc >= startp;) {
 550                         c = *loc;
 551                         *loc = '\0';
 552                         if (patmatch(str, startp, varflags & VSQUOTE)) {
 553                                 *loc = c;
 554                                 goto recordleft;
 555                         }
 556                         *loc = c;
 557                         loc--;
 558                         if ((varflags & VSQUOTE) && loc > startp &&
 559                             *(loc - 1) == CTLESC) {
 560                                 for (q = startp; q < loc; q++)
 561                                         if (*q == CTLESC)
 562                                                 q++;
 563                                 if (q > loc)
 564                                         loc--;
 565                         }
 566                 }
 567                 return 0;
 568
 569         case VSTRIMRIGHT:
 570                 for (loc = str - 1; loc >= startp;) {
 571                         if (patmatch(str, loc, varflags & VSQUOTE)) {
 572                                 amount = loc - expdest;
 573                                 STADJUST(amount, expdest);
 574                                 return 1;
 575                         }
 576                         loc--;
 577                         if ((varflags & VSQUOTE) && loc > startp &&
 578                             *(loc - 1) == CTLESC) {
 579                                 for (q = startp; q < loc; q++)
 580                                         if (*q == CTLESC)
 581                                                 q++;
 582                                 if (q > loc)
 583                                         loc--;
 584                         }
 585                 }
 586                 return 0;
 587
 588         case VSTRIMRIGHTMAX:
 589                 for (loc = startp; loc < str - 1; loc++) {
 590                         if (patmatch(str, loc, varflags & VSQUOTE)) {
 591                                 amount = loc - expdest;
 592                                 STADJUST(amount, expdest);
 593                                 return 1;
 594                         }
 595                         if ((varflags & VSQUOTE) && *loc == CTLESC)
 596                                 loc++;
 597                 }
 598                 return 0;
 599
 600
 601         default:
 602                 abort();
 603         }
 604
 605 recordleft:
 606         amount = ((str - 1) - (loc - startp)) - expdest;
 607         STADJUST(amount, expdest);
 608         while (loc != str - 1)
 609                 *startp++ = *loc++;
 610         return 1;
 611 }
 612
 613
 614 /*
 615  * Expand a variable, and return a pointer to the next character in the
 616  * input string.
 617  */
 618
 619 STATIC char *
 620 evalvar(char *p, int flag)
 621 {
 622         int subtype;
 623         int varflags;
 624         char *var;
 625         char *val;
 626         int patloc;
 627         int c;
 628         int set;
 629         int special;
 630         int startloc;
 631         int varlen;
 632         int easy;
 633         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
 634
 635         varflags = *p++;
 636         subtype = varflags & VSTYPE;
 637         var = p;
 638         special = 0;
 639         if (! is_name(*p))
 640                 special = 1;
 641         p = strchr(p, '=') + 1;
 642 again: /* jump here after setting a variable with ${var=text} */
 643         if (special) {
 644                 set = varisset(var, varflags & VSNUL);
 645                 val = NULL;
 646         } else {
 647                 val = bltinlookup(var, 1);
 648                 if (val == NULL || ((varflags & VSNUL) && val[0] == '\0')) {
 649                         val = NULL;
 650                         set = 0;
 651                 } else
 652                         set = 1;
 653         }
 654         varlen = 0;
 655         startloc = expdest - stackblock();
 656         if (!set && uflag) {
 657                 switch (subtype) {
 658                 case VSNORMAL:
 659                 case VSTRIMLEFT:
 660                 case VSTRIMLEFTMAX:
 661                 case VSTRIMRIGHT:
 662                 case VSTRIMRIGHTMAX:
 663                 case VSLENGTH:
 664                         error("%.*s: parameter not set", p - var - 1, var);
 665                 }
 666         }
 667         if (set && subtype != VSPLUS) {
 668                 /* insert the value of the variable */
 669                 if (special) {
 670                         varvalue(var, varflags & VSQUOTE, flag & EXP_FULL);
 671                         if (subtype == VSLENGTH) {
 672                                 varlen = expdest - stackblock() - startloc;
 673                                 STADJUST(-varlen, expdest);
 674                         }
 675                 } else {
 676                         char const *syntax = (varflags & VSQUOTE) ? DQSYNTAX
 677                                                                   : BASESYNTAX;
 678
 679                         if (subtype == VSLENGTH) {
 680                                 for (;*val; val++)
 681                                         varlen++;
 682                         }
 683                         else {
 684                                 while (*val) {
 685                                         if (quotes &&
 686                                             syntax[(int)*val] == CCTL)
 687                                                 STPUTC(CTLESC, expdest);
 688                                         STPUTC(*val++, expdest);
 689                                 }
 690
 691                         }
 692                 }
 693         }
 694
 695         if (subtype == VSPLUS)
 696                 set = ! set;
 697
 698         easy = ((varflags & VSQUOTE) == 0 ||
 699                 (*var == '@' && shellparam.nparam != 1));
 700
 701
 702         switch (subtype) {
 703         case VSLENGTH:
 704                 expdest = cvtnum(varlen, expdest);
 705                 goto record;
 706
 707         case VSNORMAL:
 708                 if (!easy)
 709                         break;
 710 record:
 711                 recordregion(startloc, expdest - stackblock(),
 712                              varflags & VSQUOTE);
 713                 break;
 714
 715         case VSPLUS:
 716         case VSMINUS:
 717                 if (!set) {
 718                         argstr(p, flag);
 719                         break;
 720                 }
 721                 if (easy)
 722                         goto record;
 723                 break;
 724
 725         case VSTRIMLEFT:
 726         case VSTRIMLEFTMAX:
 727         case VSTRIMRIGHT:
 728         case VSTRIMRIGHTMAX:
 729                 if (!set)
 730                         break;
 731                 /*
 732                  * Terminate the string and start recording the pattern
 733                  * right after it
 734                  */
 735                 STPUTC('\0', expdest);
 736                 patloc = expdest - stackblock();
 737                 if (subevalvar(p, NULL, patloc, subtype,
 738                                startloc, varflags) == 0) {
 739                         int amount = (expdest - stackblock() - patloc) + 1;
 740                         STADJUST(-amount, expdest);
 741                 }
 742                 /* Remove any recorded regions beyond start of variable */
 743                 removerecordregions(startloc);
 744                 goto record;
 745
 746         case VSASSIGN:
 747         case VSQUESTION:
 748                 if (!set) {
 749                         if (subevalvar(p, var, 0, subtype, startloc, varflags)) {
 750                                 varflags &= ~VSNUL;
 751                                 /*
 752                                  * Remove any recorded regions beyond
 753                                  * start of variable
 754                                  */
 755                                 removerecordregions(startloc);
 756                                 goto again;
 757                         }
 758                         break;
 759                 }
 760                 if (easy)
 761                         goto record;
 762                 break;
 763
 764         default:
 765                 abort();
 766         }
 767
 768         if (subtype != VSNORMAL) {      /* skip to end of alternative */
 769                 int nesting = 1;
 770                 for (;;) {
 771                         if ((c = *p++) == CTLESC)
 772                                 p++;
 773                         else if (c == CTLBACKQ || c == (CTLBACKQ|CTLQUOTE)) {
 774                                 if (set)
 775                                         argbackq = argbackq->next;
 776                         } else if (c == CTLVAR) {
 777                                 if ((*p++ & VSTYPE) != VSNORMAL)
 778                                         nesting++;
 779                         } else if (c == CTLENDVAR) {
 780                                 if (--nesting == 0)
 781                                         break;
 782                         }
 783                 }
 784         }
 785         return p;
 786 }
 787
 788
 789
 790 /*
 791  * Test whether a specialized variable is set.
 792  */
 793
 794 STATIC int
 795 varisset(char *name, int nulok)
 796 {
 797
 798         if (*name == '!')
 799                 return backgndpid != -1;
 800         else if (*name == '@' || *name == '*') {
 801                 if (*shellparam.p == NULL)
 802                         return 0;
 803
 804                 if (nulok) {
 805                         char **av;
 806
 807                         for (av = shellparam.p; *av; av++)
 808                                 if (**av != '\0')
 809                                         return 1;
 810                         return 0;
 811                 }
 812         } else if (is_digit(*name)) {
 813                 char *ap;
 814                 int num = atoi(name);
 815
 816                 if (num > shellparam.nparam)
 817                         return 0;
 818
 819                 if (num == 0)
 820                         ap = arg0;
 821                 else
 822                         ap = shellparam.p[num - 1];
 823
 824                 if (nulok && (ap == NULL || *ap == '\0'))
 825                         return 0;
 826         }
 827         return 1;
 828 }
 829
 830
 831
 832 /*
 833  * Add the value of a specialized variable to the stack string.
 834  */
 835
 836 STATIC void
 837 varvalue(char *name, int quoted, int allow_split)
 838 {
 839         int num;
 840         char *p;
 841         int i;
 842         extern int oexitstatus;
 843         char sep;
 844         char **ap;
 845         char const *syntax;
 846
 847 #define STRTODEST(p) \
 848         do {\
 849         if (allow_split) { \
 850                 syntax = quoted? DQSYNTAX : BASESYNTAX; \
 851                 while (*p) { \
 852                         if (syntax[(int)*p] == CCTL) \
 853                                 STPUTC(CTLESC, expdest); \
 854                         STPUTC(*p++, expdest); \
 855                 } \
 856         } else \
 857                 while (*p) \
 858                         STPUTC(*p++, expdest); \
 859         } while (0)
 860
 861
 862         switch (*name) {
 863         case '$':
 864                 num = rootpid;
 865                 goto numvar;
 866         case '?':
 867                 num = oexitstatus;
 868                 goto numvar;
 869         case '#':
 870                 num = shellparam.nparam;
 871                 goto numvar;
 872         case '!':
 873                 num = backgndpid;
 874 numvar:
 875                 expdest = cvtnum(num, expdest);
 876                 break;
 877         case '-':
 878                 for (i = 0 ; i < NOPTS ; i++) {
 879                         if (optlist[i].val)
 880                                 STPUTC(optlist[i].letter, expdest);
 881                 }
 882                 break;
 883         case '@':
 884                 if (allow_split && quoted) {
 885                         for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
 886                                 STRTODEST(p);
 887                                 if (*ap)
 888                                         STPUTC('\0', expdest);
 889                         }
 890                         break;
 891                 }
 892                 /* fall through */
 893         case '*':
 894                 if (ifsset() != 0)
 895                         sep = ifsval()[0];
 896                 else
 897                         sep = ' ';
 898                 for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
 899                         STRTODEST(p);
 900                         if (*ap && sep)
 901                                 STPUTC(sep, expdest);
 902                 }
 903                 break;
 904         case '0':
 905                 p = arg0;
 906                 STRTODEST(p);
 907                 break;
 908         default:
 909                 if (is_digit(*name)) {
 910                         num = atoi(name);
 911                         if (num > 0 && num <= shellparam.nparam) {
 912                                 p = shellparam.p[num - 1];
 913                                 STRTODEST(p);
 914                         }
 915                 }
 916                 break;
 917         }
 918 }
 919
 920
 921
 922 /*
 923  * Record the the fact that we have to scan this region of the
 924  * string for IFS characters.
 925  */
 926
 927 STATIC void
 928 recordregion(int start, int end, int nulonly)
 929 {
 930         struct ifsregion *ifsp;
 931
 932         if (ifslastp == NULL) {
 933                 ifsp = &ifsfirst;
 934         } else {
 935                 ifsp = (struct ifsregion *)ckmalloc(sizeof (struct ifsregion));
 936                 ifslastp->next = ifsp;
 937         }
 938         ifslastp = ifsp;
 939         ifslastp->next = NULL;
 940         ifslastp->begoff = start;
 941         ifslastp->endoff = end;
 942         ifslastp->nulonly = nulonly;
 943 }
 944
 945
 946
 947 /*
 948  * Break the argument string into pieces based upon IFS and add the
 949  * strings to the argument list.  The regions of the string to be
 950  * searched for IFS characters have been stored by recordregion.
 951  */
 952 STATIC void
 953 ifsbreakup(char *string, struct arglist *arglist)
 954 {
 955         struct ifsregion *ifsp;
 956         struct strlist *sp;
 957         char *start;
 958         char *p;
 959         char *q;
 960         const char *ifs;
 961         int ifsspc;
 962         int nulonly;
 963
 964
 965         start = string;
 966         ifsspc = 0;
 967         nulonly = 0;
 968         if (ifslastp != NULL) {
 969                 ifsp = &ifsfirst;
 970                 do {
 971                         p = string + ifsp->begoff;
 972                         nulonly = ifsp->nulonly;
 973                         ifs = nulonly ? nullstr :
 974                                 ( ifsset() ? ifsval() : " \t\n" );
 975                         ifsspc = 0;
 976                         while (p < string + ifsp->endoff) {
 977                                 q = p;
 978                                 if (*p == CTLESC)
 979                                         p++;
 980                                 if (strchr(ifs, *p)) {
 981                                         if (!nulonly)
 982                                                 ifsspc = (strchr(" \t\n", *p) != NULL);
 983                                         /* Ignore IFS whitespace at start */
 984                                         if (q == start && ifsspc) {
 985                                                 p++;
 986                                                 start = p;
 987                                                 continue;
 988                                         }
 989                                         *q = '\0';
 990                                         sp = (struct strlist *)stalloc(sizeof *sp);
 991                                         sp->text = start;
 992                                         *arglist->lastp = sp;
 993                                         arglist->lastp = &sp->next;
 994                                         p++;
 995                                         if (!nulonly) {
 996                                                 for (;;) {
 997                                                         if (p >= string + ifsp->endoff) {
 998                                                                 break;
 999                                                         }
1000                                                         q = p;
1001                                                         if (*p == CTLESC)
1002                                                                 p++;
1003                                                         if (strchr(ifs, *p) == NULL ) {
1004                                                                 p = q;
1005                                                                 break;
1006                                                         } else if (strchr(" \t\n",*p) == NULL) {
1007                                                                 if (ifsspc) {
1008                                                                         p++;
1009                                                                         ifsspc = 0;
1010                                                                 } else {
1011                                                                         p = q;
1012                                                                         break;
1013                                                                 }
1014                                                         } else
1015                                                                 p++;
1016                                                 }
1017                                         }
1018                                         start = p;
1019                                 } else
1020                                         p++;
1021                         }
1022                 } while ((ifsp = ifsp->next) != NULL);
1023                 if (*start || (!ifsspc && start > string &&
1024                         (nulonly || 1))) {
1025                         sp = (struct strlist *)stalloc(sizeof *sp);
1026                         sp->text = start;
1027                         *arglist->lastp = sp;
1028                         arglist->lastp = &sp->next;
1029                 }
1030         } else {
1031                 sp = (struct strlist *)stalloc(sizeof *sp);
1032                 sp->text = start;
1033                 *arglist->lastp = sp;
1034                 arglist->lastp = &sp->next;
1035         }
1036 }
1037
1038
1039
1040 /*
1041  * Expand shell metacharacters.  At this point, the only control characters
1042  * should be escapes.  The results are stored in the list exparg.
1043  */
1044
1045 STATIC char *expdir;
1046
1047
1048 STATIC void
1049 expandmeta(struct strlist *str, int flag __unused)
1050 {
1051         char *p;
1052         struct strlist **savelastp;
1053         struct strlist *sp;
1054         char c;
1055         /* TODO - EXP_REDIR */
1056
1057         while (str) {
1058                 if (fflag)
1059                         goto nometa;
1060                 p = str->text;
1061                 for (;;) {                      /* fast check for meta chars */
1062                         if ((c = *p++) == '\0')
1063                                 goto nometa;
1064                         if (c == '*' || c == '?' || c == '[' || c == '!')
1065                                 break;
1066                 }
1067                 savelastp = exparg.lastp;
1068                 INTOFF;
1069                 if (expdir == NULL) {
1070                         int i = strlen(str->text);
1071                         expdir = ckmalloc(i < 2048 ? 2048 : i); /* XXX */
1072                 }
1073
1074                 expmeta(expdir, str->text);
1075                 ckfree(expdir);
1076                 expdir = NULL;
1077                 INTON;
1078                 if (exparg.lastp == savelastp) {
1079                         /*
1080                          * no matches
1081                          */
1082 nometa:
1083                         *exparg.lastp = str;
1084                         rmescapes(str->text);
1085                         exparg.lastp = &str->next;
1086                 } else {
1087                         *exparg.lastp = NULL;
1088                         *savelastp = sp = expsort(*savelastp);
1089                         while (sp->next != NULL)
1090                                 sp = sp->next;
1091                         exparg.lastp = &sp->next;
1092                 }
1093                 str = str->next;
1094         }
1095 }
1096
1097
1098 /*
1099  * Do metacharacter (i.e. *, ?, [...]) expansion.
1100  */
1101
1102 STATIC void
1103 expmeta(char *enddir, char *name)
1104 {
1105         char *p;
1106         const char *q;
1107         char *start;
1108         char *endname;
1109         int metaflag;
1110         struct stat statb;
1111         DIR *dirp;
1112         struct dirent *dp;
1113         int atend;
1114         int matchdot;
1115
1116         metaflag = 0;
1117         start = name;
1118         for (p = name ; ; p++) {
1119                 if (*p == '*' || *p == '?')
1120                         metaflag = 1;
1121                 else if (*p == '[') {
1122                         q = p + 1;
1123                         if (*q == '!' || *q == '^')
1124                                 q++;
1125                         for (;;) {
1126                                 while (*q == CTLQUOTEMARK)
1127                                         q++;
1128                                 if (*q == CTLESC)
1129                                         q++;
1130                                 if (*q == '/' || *q == '\0')
1131                                         break;
1132                                 if (*++q == ']') {
1133                                         metaflag = 1;
1134                                         break;
1135                                 }
1136                         }
1137                 } else if (*p == '!' && p[1] == '!'     && (p == name || p[-1] == '/')) {
1138                         metaflag = 1;
1139                 } else if (*p == '\0')
1140                         break;
1141                 else if (*p == CTLQUOTEMARK)
1142                         continue;
1143                 else if (*p == CTLESC)
1144                         p++;
1145                 if (*p == '/') {
1146                         if (metaflag)
1147                                 break;
1148                         start = p + 1;
1149                 }
1150         }
1151         if (metaflag == 0) {    /* we've reached the end of the file name */
1152                 if (enddir != expdir)
1153                         metaflag++;
1154                 for (p = name ; ; p++) {
1155                         if (*p == CTLQUOTEMARK)
1156                                 continue;
1157                         if (*p == CTLESC)
1158                                 p++;
1159                         *enddir++ = *p;
1160                         if (*p == '\0')
1161                                 break;
1162                 }
1163                 if (metaflag == 0 || stat(expdir, &statb) >= 0)
1164                         addfname(expdir);
1165                 return;
1166         }
1167         endname = p;
1168         if (start != name) {
1169                 p = name;
1170                 while (p < start) {
1171                         while (*p == CTLQUOTEMARK)
1172                                 p++;
1173                         if (*p == CTLESC)
1174                                 p++;
1175                         *enddir++ = *p++;
1176                 }
1177         }
1178         if (enddir == expdir) {
1179                 q = ".";
1180         } else if (enddir == expdir + 1 && *expdir == '/') {
1181                 q = "/";
1182         } else {
1183                 q = expdir;
1184                 enddir[-1] = '\0';
1185         }
1186         if ((dirp = opendir(q)) == NULL)
1187                 return;
1188         if (enddir != expdir)
1189                 enddir[-1] = '/';
1190         if (*endname == 0) {
1191                 atend = 1;
1192         } else {
1193                 atend = 0;
1194                 *endname++ = '\0';
1195         }
1196         matchdot = 0;
1197         p = start;
1198         while (*p == CTLQUOTEMARK)
1199                 p++;
1200         if (*p == CTLESC)
1201                 p++;
1202         if (*p == '.')
1203                 matchdot++;
1204         while (! int_pending() && (dp = readdir(dirp)) != NULL) {
1205                 if (dp->d_name[0] == '.' && ! matchdot)
1206                         continue;
1207                 if (patmatch(start, dp->d_name, 0)) {
1208                         if (atend) {
1209                                 scopy(dp->d_name, enddir);
1210                                 addfname(expdir);
1211                         } else {
1212                                 char *t;
1213                                 for (t = enddir, q = dp->d_name;
1214                                      (*t++ = *q++) != '\0';)
1215                                         continue;
1216                                 t[-1] = '/';
1217                                 expmeta(t, endname);
1218                         }
1219                 }
1220         }
1221         closedir(dirp);
1222         if (! atend)
1223                 endname[-1] = '/';
1224 }
1225
1226
1227 /*
1228  * Add a file name to the list.
1229  */
1230
1231 STATIC void
1232 addfname(char *name)
1233 {
1234         char *p;
1235         struct strlist *sp;
1236
1237         p = stalloc(strlen(name) + 1);
1238         scopy(name, p);
1239         sp = (struct strlist *)stalloc(sizeof *sp);
1240         sp->text = p;
1241         *exparg.lastp = sp;
1242         exparg.lastp = &sp->next;
1243 }
1244
1245
1246 /*
1247  * Sort the results of file name expansion.  It calculates the number of
1248  * strings to sort and then calls msort (short for merge sort) to do the
1249  * work.
1250  */
1251
1252 STATIC struct strlist *
1253 expsort(struct strlist *str)
1254 {
1255         int len;
1256         struct strlist *sp;
1257
1258         len = 0;
1259         for (sp = str ; sp ; sp = sp->next)
1260                 len++;
1261         return msort(str, len);
1262 }
1263
1264
1265 STATIC struct strlist *
1266 msort(struct strlist *list, int len)
1267 {
1268         struct strlist *p, *q = NULL;
1269         struct strlist **lpp;
1270         int half;
1271         int n;
1272
1273         if (len <= 1)
1274                 return list;
1275         half = len >> 1;
1276         p = list;
1277         for (n = half ; --n >= 0 ; ) {
1278                 q = p;
1279                 p = p->next;
1280         }
1281         q->next = NULL;                 /* terminate first half of list */
1282         q = msort(list, half);          /* sort first half of list */
1283         p = msort(p, len - half);               /* sort second half */
1284         lpp = &list;
1285         for (;;) {
1286                 if (strcmp(p->text, q->text) < 0) {
1287                         *lpp = p;
1288                         lpp = &p->next;
1289                         if ((p = *lpp) == NULL) {
1290                                 *lpp = q;
1291                                 break;
1292                         }
1293                 } else {
1294                         *lpp = q;
1295                         lpp = &q->next;
1296                         if ((q = *lpp) == NULL) {
1297                                 *lpp = p;
1298                                 break;
1299                         }
1300                 }
1301         }
1302         return list;
1303 }
1304
1305
1306
1307 /*
1308  * Returns true if the pattern matches the string.
1309  */
1310
1311 int
1312 patmatch(char *pattern, char *string, int squoted)
1313 {
1314 #ifdef notdef
1315         if (pattern[0] == '!' && pattern[1] == '!')
1316                 return 1 - pmatch(pattern + 2, string);
1317         else
1318 #endif
1319                 return pmatch(pattern, string, squoted);
1320 }
1321
1322
1323 STATIC int
1324 pmatch(char *pattern, char *string, int squoted)
1325 {
1326         char *p, *q;
1327         char c;
1328
1329         p = pattern;
1330         q = string;
1331         for (;;) {
1332                 switch (c = *p++) {
1333                 case '\0':
1334                         goto breakloop;
1335                 case CTLESC:
1336                         if (squoted && *q == CTLESC)
1337                                 q++;
1338                         if (*q++ != *p++)
1339                                 return 0;
1340                         break;
1341                 case CTLQUOTEMARK:
1342                         continue;
1343                 case '?':
1344                         if (squoted && *q == CTLESC)
1345                                 q++;
1346                         if (*q++ == '\0')
1347                                 return 0;
1348                         break;
1349                 case '*':
1350                         c = *p;
1351                         while (c == CTLQUOTEMARK || c == '*')
1352                                 c = *++p;
1353                         if (c != CTLESC &&  c != CTLQUOTEMARK &&
1354                             c != '?' && c != '*' && c != '[') {
1355                                 while (*q != c) {
1356                                         if (squoted && *q == CTLESC &&
1357                                             q[1] == c)
1358                                                 break;
1359                                         if (*q == '\0')
1360                                                 return 0;
1361                                         if (squoted && *q == CTLESC)
1362                                                 q++;
1363                                         q++;
1364                                 }
1365                         }
1366                         do {
1367                                 if (pmatch(p, q, squoted))
1368                                         return 1;
1369                                 if (squoted && *q == CTLESC)
1370                                         q++;
1371                         } while (*q++ != '\0');
1372                         return 0;
1373                 case '[': {
1374                         char *endp;
1375                         int invert, found;
1376                         char chr;
1377
1378                         endp = p;
1379                         if (*endp == '!' || *endp == '^')
1380                                 endp++;
1381                         for (;;) {
1382                                 while (*endp == CTLQUOTEMARK)
1383                                         endp++;
1384                                 if (*endp == '\0')
1385                                         goto dft;               /* no matching ] */
1386                                 if (*endp == CTLESC)
1387                                         endp++;
1388                                 if (*++endp == ']')
1389                                         break;
1390                         }
1391                         invert = 0;
1392                         if (*p == '!' || *p == '^') {
1393                                 invert++;
1394                                 p++;
1395                         }
1396                         found = 0;
1397                         chr = *q++;
1398                         if (squoted && chr == CTLESC)
1399                                 chr = *q++;
1400                         if (chr == '\0')
1401                                 return 0;
1402                         c = *p++;
1403                         do {
1404                                 if (c == CTLQUOTEMARK)
1405                                         continue;
1406                                 if (c == CTLESC)
1407                                         c = *p++;
1408                                 if (*p == '-' && p[1] != ']') {
1409                                         p++;
1410                                         while (*p == CTLQUOTEMARK)
1411                                                 p++;
1412                                         if (*p == CTLESC)
1413                                                 p++;
1414                                         if (   collate_range_cmp(chr, c) >= 0
1415                                             && collate_range_cmp(chr, *p) <= 0
1416                                            )
1417                                                 found = 1;
1418                                         p++;
1419                                 } else {
1420                                         if (chr == c)
1421                                                 found = 1;
1422                                 }
1423                         } while ((c = *p++) != ']');
1424                         if (found == invert)
1425                                 return 0;
1426                         break;
1427                 }
1428 dft:            default:
1429                         if (squoted && *q == CTLESC)
1430                                 q++;
1431                         if (*q++ != c)
1432                                 return 0;
1433                         break;
1434                 }
1435         }
1436 breakloop:
1437         if (*q != '\0')
1438                 return 0;
1439         return 1;
1440 }
1441
1442
1443
1444 /*
1445  * Remove any CTLESC characters from a string.
1446  */
1447
1448 void
1449 rmescapes(char *str)
1450 {
1451         char *p, *q;
1452
1453         p = str;
1454         while (*p != CTLESC && *p != CTLQUOTEMARK) {
1455                 if (*p++ == '\0')
1456                         return;
1457         }
1458         q = p;
1459         while (*p) {
1460                 if (*p == CTLQUOTEMARK) {
1461                         p++;
1462                         continue;
1463                 }
1464                 if (*p == CTLESC)
1465                         p++;
1466                 *q++ = *p++;
1467         }
1468         *q = '\0';
1469 }
1470
1471
1472
1473 /*
1474  * See if a pattern matches in a case statement.
1475  */
1476
1477 int
1478 casematch(union node *pattern, char *val)
1479 {
1480         struct stackmark smark;
1481         int result;
1482         char *p;
1483
1484         setstackmark(&smark);
1485         argbackq = pattern->narg.backquote;
1486         STARTSTACKSTR(expdest);
1487         ifslastp = NULL;
1488         argstr(pattern->narg.text, EXP_TILDE | EXP_CASE);
1489         STPUTC('\0', expdest);
1490         p = grabstackstr(expdest);
1491         result = patmatch(p, val, 0);
1492         popstackmark(&smark);
1493         return result;
1494 }
1495
1496 /*
1497  * Our own itoa().
1498  */
1499
1500 STATIC char *
1501 cvtnum(int num, char *buf)
1502 {
1503         char temp[32];
1504         int neg = num < 0;
1505         char *p = temp + 31;
1506
1507         temp[31] = '\0';
1508
1509         do {
1510                 *--p = num % 10 + '0';
1511         } while ((num /= 10) != 0);
1512
1513         if (neg)
1514                 *--p = '-';
1515
1516         while (*p)
1517                 STPUTC(*p++, buf);
1518         return buf;
1519 }