bin/sh/parser.c

   1 /*-
   2  * Copyright (c) 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Kenneth Almquist.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 4. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #ifndef lint
  34 #if 0
  35 static char sccsid[] = "@(#)parser.c    8.7 (Berkeley) 5/16/95";
  36 #endif
  37 #endif /* not lint */
  38 #include <sys/cdefs.h>
  39 __FBSDID("$FreeBSD$");
  40
  41 #include <stdlib.h>
  42 #include <unistd.h>
  43 #include <stdio.h>
  44
  45 #include "shell.h"
  46 #include "parser.h"
  47 #include "nodes.h"
  48 #include "expand.h"     /* defines rmescapes() */
  49 #include "syntax.h"
  50 #include "options.h"
  51 #include "input.h"
  52 #include "output.h"
  53 #include "var.h"
  54 #include "error.h"
  55 #include "memalloc.h"
  56 #include "mystring.h"
  57 #include "alias.h"
  58 #include "show.h"
  59 #include "eval.h"
  60 #include "exec.h"       /* to check for special builtins */
  61 #ifndef NO_HISTORY
  62 #include "myhistedit.h"
  63 #endif
  64
  65 /*
  66  * Shell command parser.
  67  */
  68
  69 #define EOFMARKLEN      79
  70 #define PROMPTLEN       128
  71
  72 /* values of checkkwd variable */
  73 #define CHKALIAS        0x1
  74 #define CHKKWD          0x2
  75 #define CHKNL           0x4
  76
  77 /* values returned by readtoken */
  78 #include "token.h"
  79
  80
  81
  82 struct heredoc {
  83         struct heredoc *next;   /* next here document in list */
  84         union node *here;               /* redirection node */
  85         char *eofmark;          /* string indicating end of input */
  86         int striptabs;          /* if set, strip leading tabs */
  87 };
  88
  89 struct parser_temp {
  90         struct parser_temp *next;
  91         void *data;
  92 };
  93
  94
  95 static struct heredoc *heredoclist;     /* list of here documents to read */
  96 static int doprompt;            /* if set, prompt the user */
  97 static int needprompt;          /* true if interactive and at start of line */
  98 static int lasttoken;           /* last token read */
  99 static int tokpushback;         /* last token pushed back */
 100 static char *wordtext;          /* text of last word returned by readtoken */
 101 static int checkkwd;
 102 static struct nodelist *backquotelist;
 103 static union node *redirnode;
 104 static struct heredoc *heredoc;
 105 static int quoteflag;           /* set if (part of) last token was quoted */
 106 static int startlinno;          /* line # where last token started */
 107 static int funclinno;           /* line # where the current function started */
 108 static struct parser_temp *parser_temp;
 109
 110
 111 static union node *list(int);
 112 static union node *andor(void);
 113 static union node *pipeline(void);
 114 static union node *command(void);
 115 static union node *simplecmd(union node **, union node *);
 116 static union node *makename(void);
 117 static union node *makebinary(int type, union node *n1, union node *n2);
 118 static void parsefname(void);
 119 static void parseheredoc(void);
 120 static int peektoken(void);
 121 static int readtoken(void);
 122 static int xxreadtoken(void);
 123 static int readtoken1(int, const char *, const char *, int);
 124 static int noexpand(char *);
 125 static void consumetoken(int);
 126 static void synexpect(int) __dead2;
 127 static void synerror(const char *) __dead2;
 128 static void setprompt(int);
 129
 130
 131 static void *
 132 parser_temp_alloc(size_t len)
 133 {
 134         struct parser_temp *t;
 135
 136         INTOFF;
 137         t = ckmalloc(sizeof(*t));
 138         t->data = NULL;
 139         t->next = parser_temp;
 140         parser_temp = t;
 141         t->data = ckmalloc(len);
 142         INTON;
 143         return t->data;
 144 }
 145
 146
 147 static void *
 148 parser_temp_realloc(void *ptr, size_t len)
 149 {
 150         struct parser_temp *t;
 151
 152         INTOFF;
 153         t = parser_temp;
 154         if (ptr != t->data)
 155                 error("bug: parser_temp_realloc misused");
 156         t->data = ckrealloc(t->data, len);
 157         INTON;
 158         return t->data;
 159 }
 160
 161
 162 static void
 163 parser_temp_free_upto(void *ptr)
 164 {
 165         struct parser_temp *t;
 166         int done = 0;
 167
 168         INTOFF;
 169         while (parser_temp != NULL && !done) {
 170                 t = parser_temp;
 171                 parser_temp = t->next;
 172                 done = t->data == ptr;
 173                 ckfree(t->data);
 174                 ckfree(t);
 175         }
 176         INTON;
 177         if (!done)
 178                 error("bug: parser_temp_free_upto misused");
 179 }
 180
 181
 182 static void
 183 parser_temp_free_all(void)
 184 {
 185         struct parser_temp *t;
 186
 187         INTOFF;
 188         while (parser_temp != NULL) {
 189                 t = parser_temp;
 190                 parser_temp = t->next;
 191                 ckfree(t->data);
 192                 ckfree(t);
 193         }
 194         INTON;
 195 }
 196
 197
 198 /*
 199  * Read and parse a command.  Returns NEOF on end of file.  (NULL is a
 200  * valid parse tree indicating a blank line.)
 201  */
 202
 203 union node *
 204 parsecmd(int interact)
 205 {
 206         int t;
 207
 208         /* This assumes the parser is not re-entered,
 209          * which could happen if we add command substitution on PS1/PS2.
 210          */
 211         parser_temp_free_all();
 212         heredoclist = NULL;
 213
 214         tokpushback = 0;
 215         checkkwd = 0;
 216         doprompt = interact;
 217         if (doprompt)
 218                 setprompt(1);
 219         else
 220                 setprompt(0);
 221         needprompt = 0;
 222         t = readtoken();
 223         if (t == TEOF)
 224                 return NEOF;
 225         if (t == TNL)
 226                 return NULL;
 227         tokpushback++;
 228         return list(1);
 229 }
 230
 231
 232 static union node *
 233 list(int nlflag)
 234 {
 235         union node *ntop, *n1, *n2, *n3;
 236         int tok;
 237
 238         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 239         if (!nlflag && tokendlist[peektoken()])
 240                 return NULL;
 241         ntop = n1 = NULL;
 242         for (;;) {
 243                 n2 = andor();
 244                 tok = readtoken();
 245                 if (tok == TBACKGND) {
 246                         if (n2 != NULL && n2->type == NPIPE) {
 247                                 n2->npipe.backgnd = 1;
 248                         } else if (n2 != NULL && n2->type == NREDIR) {
 249                                 n2->type = NBACKGND;
 250                         } else {
 251                                 n3 = (union node *)stalloc(sizeof (struct nredir));
 252                                 n3->type = NBACKGND;
 253                                 n3->nredir.n = n2;
 254                                 n3->nredir.redirect = NULL;
 255                                 n2 = n3;
 256                         }
 257                 }
 258                 if (ntop == NULL)
 259                         ntop = n2;
 260                 else if (n1 == NULL) {
 261                         n1 = makebinary(NSEMI, ntop, n2);
 262                         ntop = n1;
 263                 }
 264                 else {
 265                         n3 = makebinary(NSEMI, n1->nbinary.ch2, n2);
 266                         n1->nbinary.ch2 = n3;
 267                         n1 = n3;
 268                 }
 269                 switch (tok) {
 270                 case TBACKGND:
 271                 case TSEMI:
 272                         tok = readtoken();
 273                         /* FALLTHROUGH */
 274                 case TNL:
 275                         if (tok == TNL) {
 276                                 parseheredoc();
 277                                 if (nlflag)
 278                                         return ntop;
 279                         } else if (tok == TEOF && nlflag) {
 280                                 parseheredoc();
 281                                 return ntop;
 282                         } else {
 283                                 tokpushback++;
 284                         }
 285                         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 286                         if (!nlflag && tokendlist[peektoken()])
 287                                 return ntop;
 288                         break;
 289                 case TEOF:
 290                         if (heredoclist)
 291                                 parseheredoc();
 292                         else
 293                                 pungetc();              /* push back EOF on input */
 294                         return ntop;
 295                 default:
 296                         if (nlflag)
 297                                 synexpect(-1);
 298                         tokpushback++;
 299                         return ntop;
 300                 }
 301         }
 302 }
 303
 304
 305
 306 static union node *
 307 andor(void)
 308 {
 309         union node *n;
 310         int t;
 311
 312         n = pipeline();
 313         for (;;) {
 314                 if ((t = readtoken()) == TAND) {
 315                         t = NAND;
 316                 } else if (t == TOR) {
 317                         t = NOR;
 318                 } else {
 319                         tokpushback++;
 320                         return n;
 321                 }
 322                 n = makebinary(t, n, pipeline());
 323         }
 324 }
 325
 326
 327
 328 static union node *
 329 pipeline(void)
 330 {
 331         union node *n1, *n2, *pipenode;
 332         struct nodelist *lp, *prev;
 333         int negate, t;
 334
 335         negate = 0;
 336         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 337         TRACE(("pipeline: entered\n"));
 338         while (readtoken() == TNOT)
 339                 negate = !negate;
 340         tokpushback++;
 341         n1 = command();
 342         if (readtoken() == TPIPE) {
 343                 pipenode = (union node *)stalloc(sizeof (struct npipe));
 344                 pipenode->type = NPIPE;
 345                 pipenode->npipe.backgnd = 0;
 346                 lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 347                 pipenode->npipe.cmdlist = lp;
 348                 lp->n = n1;
 349                 do {
 350                         prev = lp;
 351                         lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 352                         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 353                         t = readtoken();
 354                         tokpushback++;
 355                         if (t == TNOT)
 356                                 lp->n = pipeline();
 357                         else
 358                                 lp->n = command();
 359                         prev->next = lp;
 360                 } while (readtoken() == TPIPE);
 361                 lp->next = NULL;
 362                 n1 = pipenode;
 363         }
 364         tokpushback++;
 365         if (negate) {
 366                 n2 = (union node *)stalloc(sizeof (struct nnot));
 367                 n2->type = NNOT;
 368                 n2->nnot.com = n1;
 369                 return n2;
 370         } else
 371                 return n1;
 372 }
 373
 374
 375
 376 static union node *
 377 command(void)
 378 {
 379         union node *n1, *n2;
 380         union node *ap, **app;
 381         union node *cp, **cpp;
 382         union node *redir, **rpp;
 383         int t;
 384         int is_subshell;
 385
 386         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 387         is_subshell = 0;
 388         redir = NULL;
 389         n1 = NULL;
 390         rpp = &redir;
 391
 392         /* Check for redirection which may precede command */
 393         while (readtoken() == TREDIR) {
 394                 *rpp = n2 = redirnode;
 395                 rpp = &n2->nfile.next;
 396                 parsefname();
 397         }
 398         tokpushback++;
 399
 400         switch (readtoken()) {
 401         case TIF:
 402                 n1 = (union node *)stalloc(sizeof (struct nif));
 403                 n1->type = NIF;
 404                 if ((n1->nif.test = list(0)) == NULL)
 405                         synexpect(-1);
 406                 consumetoken(TTHEN);
 407                 n1->nif.ifpart = list(0);
 408                 n2 = n1;
 409                 while (readtoken() == TELIF) {
 410                         n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
 411                         n2 = n2->nif.elsepart;
 412                         n2->type = NIF;
 413                         if ((n2->nif.test = list(0)) == NULL)
 414                                 synexpect(-1);
 415                         consumetoken(TTHEN);
 416                         n2->nif.ifpart = list(0);
 417                 }
 418                 if (lasttoken == TELSE)
 419                         n2->nif.elsepart = list(0);
 420                 else {
 421                         n2->nif.elsepart = NULL;
 422                         tokpushback++;
 423                 }
 424                 consumetoken(TFI);
 425                 checkkwd = CHKKWD | CHKALIAS;
 426                 break;
 427         case TWHILE:
 428         case TUNTIL:
 429                 t = lasttoken;
 430                 if ((n1 = list(0)) == NULL)
 431                         synexpect(-1);
 432                 consumetoken(TDO);
 433                 n1 = makebinary((t == TWHILE)? NWHILE : NUNTIL, n1, list(0));
 434                 consumetoken(TDONE);
 435                 checkkwd = CHKKWD | CHKALIAS;
 436                 break;
 437         case TFOR:
 438                 if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
 439                         synerror("Bad for loop variable");
 440                 n1 = (union node *)stalloc(sizeof (struct nfor));
 441                 n1->type = NFOR;
 442                 n1->nfor.var = wordtext;
 443                 while (readtoken() == TNL)
 444                         ;
 445                 if (lasttoken == TWORD && ! quoteflag && equal(wordtext, "in")) {
 446                         app = &ap;
 447                         while (readtoken() == TWORD) {
 448                                 n2 = makename();
 449                                 *app = n2;
 450                                 app = &n2->narg.next;
 451                         }
 452                         *app = NULL;
 453                         n1->nfor.args = ap;
 454                         if (lasttoken != TNL && lasttoken != TSEMI)
 455                                 synexpect(-1);
 456                 } else {
 457                         static char argvars[5] = {
 458                                 CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'
 459                         };
 460                         n2 = (union node *)stalloc(sizeof (struct narg));
 461                         n2->type = NARG;
 462                         n2->narg.text = argvars;
 463                         n2->narg.backquote = NULL;
 464                         n2->narg.next = NULL;
 465                         n1->nfor.args = n2;
 466                         /*
 467                          * Newline or semicolon here is optional (but note
 468                          * that the original Bourne shell only allowed NL).
 469                          */
 470                         if (lasttoken != TNL && lasttoken != TSEMI)
 471                                 tokpushback++;
 472                 }
 473                 checkkwd = CHKNL | CHKKWD | CHKALIAS;
 474                 if ((t = readtoken()) == TDO)
 475                         t = TDONE;
 476                 else if (t == TBEGIN)
 477                         t = TEND;
 478                 else
 479                         synexpect(-1);
 480                 n1->nfor.body = list(0);
 481                 consumetoken(t);
 482                 checkkwd = CHKKWD | CHKALIAS;
 483                 break;
 484         case TCASE:
 485                 n1 = (union node *)stalloc(sizeof (struct ncase));
 486                 n1->type = NCASE;
 487                 consumetoken(TWORD);
 488                 n1->ncase.expr = makename();
 489                 while (readtoken() == TNL);
 490                 if (lasttoken != TWORD || ! equal(wordtext, "in"))
 491                         synerror("expecting \"in\"");
 492                 cpp = &n1->ncase.cases;
 493                 checkkwd = CHKNL | CHKKWD, readtoken();
 494                 while (lasttoken != TESAC) {
 495                         *cpp = cp = (union node *)stalloc(sizeof (struct nclist));
 496                         cp->type = NCLIST;
 497                         app = &cp->nclist.pattern;
 498                         if (lasttoken == TLP)
 499                                 readtoken();
 500                         for (;;) {
 501                                 *app = ap = makename();
 502                                 checkkwd = CHKNL | CHKKWD;
 503                                 if (readtoken() != TPIPE)
 504                                         break;
 505                                 app = &ap->narg.next;
 506                                 readtoken();
 507                         }
 508                         ap->narg.next = NULL;
 509                         if (lasttoken != TRP)
 510                                 synexpect(TRP);
 511                         cp->nclist.body = list(0);
 512
 513                         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 514                         if ((t = readtoken()) != TESAC) {
 515                                 if (t == TENDCASE)
 516                                         ;
 517                                 else if (t == TFALLTHRU)
 518                                         cp->type = NCLISTFALLTHRU;
 519                                 else
 520                                         synexpect(TENDCASE);
 521                                 checkkwd = CHKNL | CHKKWD, readtoken();
 522                         }
 523                         cpp = &cp->nclist.next;
 524                 }
 525                 *cpp = NULL;
 526                 checkkwd = CHKKWD | CHKALIAS;
 527                 break;
 528         case TLP:
 529                 n1 = (union node *)stalloc(sizeof (struct nredir));
 530                 n1->type = NSUBSHELL;
 531                 n1->nredir.n = list(0);
 532                 n1->nredir.redirect = NULL;
 533                 consumetoken(TRP);
 534                 checkkwd = CHKKWD | CHKALIAS;
 535                 is_subshell = 1;
 536                 break;
 537         case TBEGIN:
 538                 n1 = list(0);
 539                 consumetoken(TEND);
 540                 checkkwd = CHKKWD | CHKALIAS;
 541                 break;
 542         /* A simple command must have at least one redirection or word. */
 543         case TBACKGND:
 544         case TSEMI:
 545         case TAND:
 546         case TOR:
 547         case TPIPE:
 548         case TENDCASE:
 549         case TFALLTHRU:
 550         case TEOF:
 551         case TNL:
 552         case TRP:
 553                 if (!redir)
 554                         synexpect(-1);
 555         case TWORD:
 556                 tokpushback++;
 557                 n1 = simplecmd(rpp, redir);
 558                 return n1;
 559         default:
 560                 synexpect(-1);
 561         }
 562
 563         /* Now check for redirection which may follow command */
 564         while (readtoken() == TREDIR) {
 565                 *rpp = n2 = redirnode;
 566                 rpp = &n2->nfile.next;
 567                 parsefname();
 568         }
 569         tokpushback++;
 570         *rpp = NULL;
 571         if (redir) {
 572                 if (!is_subshell) {
 573                         n2 = (union node *)stalloc(sizeof (struct nredir));
 574                         n2->type = NREDIR;
 575                         n2->nredir.n = n1;
 576                         n1 = n2;
 577                 }
 578                 n1->nredir.redirect = redir;
 579         }
 580
 581         return n1;
 582 }
 583
 584
 585 static union node *
 586 simplecmd(union node **rpp, union node *redir)
 587 {
 588         union node *args, **app;
 589         union node **orig_rpp = rpp;
 590         union node *n = NULL;
 591         int special;
 592         int savecheckkwd;
 593
 594         /* If we don't have any redirections already, then we must reset */
 595         /* rpp to be the address of the local redir variable.  */
 596         if (redir == 0)
 597                 rpp = &redir;
 598
 599         args = NULL;
 600         app = &args;
 601         /*
 602          * We save the incoming value, because we need this for shell
 603          * functions.  There can not be a redirect or an argument between
 604          * the function name and the open parenthesis.
 605          */
 606         orig_rpp = rpp;
 607
 608         savecheckkwd = CHKALIAS;
 609
 610         for (;;) {
 611                 checkkwd = savecheckkwd;
 612                 if (readtoken() == TWORD) {
 613                         n = makename();
 614                         *app = n;
 615                         app = &n->narg.next;
 616                         if (savecheckkwd != 0 && !isassignment(wordtext))
 617                                 savecheckkwd = 0;
 618                 } else if (lasttoken == TREDIR) {
 619                         *rpp = n = redirnode;
 620                         rpp = &n->nfile.next;
 621                         parsefname();   /* read name of redirection file */
 622                 } else if (lasttoken == TLP && app == &args->narg.next
 623                                             && rpp == orig_rpp) {
 624                         /* We have a function */
 625                         consumetoken(TRP);
 626                         funclinno = plinno;
 627                         /*
 628                          * - Require plain text.
 629                          * - Functions with '/' cannot be called.
 630                          * - Reject name=().
 631                          * - Reject ksh extended glob patterns.
 632                          */
 633                         if (!noexpand(n->narg.text) || quoteflag ||
 634                             strchr(n->narg.text, '/') ||
 635                             strchr("!%*+-=?@}~",
 636                                 n->narg.text[strlen(n->narg.text) - 1]))
 637                                 synerror("Bad function name");
 638                         rmescapes(n->narg.text);
 639                         if (find_builtin(n->narg.text, &special) >= 0 &&
 640                             special)
 641                                 synerror("Cannot override a special builtin with a function");
 642                         n->type = NDEFUN;
 643                         n->narg.next = command();
 644                         funclinno = 0;
 645                         return n;
 646                 } else {
 647                         tokpushback++;
 648                         break;
 649                 }
 650         }
 651         *app = NULL;
 652         *rpp = NULL;
 653         n = (union node *)stalloc(sizeof (struct ncmd));
 654         n->type = NCMD;
 655         n->ncmd.args = args;
 656         n->ncmd.redirect = redir;
 657         return n;
 658 }
 659
 660 static union node *
 661 makename(void)
 662 {
 663         union node *n;
 664
 665         n = (union node *)stalloc(sizeof (struct narg));
 666         n->type = NARG;
 667         n->narg.next = NULL;
 668         n->narg.text = wordtext;
 669         n->narg.backquote = backquotelist;
 670         return n;
 671 }
 672
 673 static union node *
 674 makebinary(int type, union node *n1, union node *n2)
 675 {
 676         union node *n;
 677
 678         n = (union node *)stalloc(sizeof (struct nbinary));
 679         n->type = type;
 680         n->nbinary.ch1 = n1;
 681         n->nbinary.ch2 = n2;
 682         return (n);
 683 }
 684
 685 void
 686 forcealias(void)
 687 {
 688         checkkwd |= CHKALIAS;
 689 }
 690
 691 void
 692 fixredir(union node *n, const char *text, int err)
 693 {
 694         TRACE(("Fix redir %s %d\n", text, err));
 695         if (!err)
 696                 n->ndup.vname = NULL;
 697
 698         if (is_digit(text[0]) && text[1] == '\0')
 699                 n->ndup.dupfd = digit_val(text[0]);
 700         else if (text[0] == '-' && text[1] == '\0')
 701                 n->ndup.dupfd = -1;
 702         else {
 703
 704                 if (err)
 705                         synerror("Bad fd number");
 706                 else
 707                         n->ndup.vname = makename();
 708         }
 709 }
 710
 711
 712 static void
 713 parsefname(void)
 714 {
 715         union node *n = redirnode;
 716
 717         consumetoken(TWORD);
 718         if (n->type == NHERE) {
 719                 struct heredoc *here = heredoc;
 720                 struct heredoc *p;
 721                 int i;
 722
 723                 if (quoteflag == 0)
 724                         n->type = NXHERE;
 725                 TRACE(("Here document %d\n", n->type));
 726                 if (here->striptabs) {
 727                         while (*wordtext == '\t')
 728                                 wordtext++;
 729                 }
 730                 if (! noexpand(wordtext) || (i = strlen(wordtext)) == 0 || i > EOFMARKLEN)
 731                         synerror("Illegal eof marker for << redirection");
 732                 rmescapes(wordtext);
 733                 here->eofmark = wordtext;
 734                 here->next = NULL;
 735                 if (heredoclist == NULL)
 736                         heredoclist = here;
 737                 else {
 738                         for (p = heredoclist ; p->next ; p = p->next);
 739                         p->next = here;
 740                 }
 741         } else if (n->type == NTOFD || n->type == NFROMFD) {
 742                 fixredir(n, wordtext, 0);
 743         } else {
 744                 n->nfile.fname = makename();
 745         }
 746 }
 747
 748
 749 /*
 750  * Input any here documents.
 751  */
 752
 753 static void
 754 parseheredoc(void)
 755 {
 756         struct heredoc *here;
 757         union node *n;
 758
 759         while (heredoclist) {
 760                 here = heredoclist;
 761                 heredoclist = here->next;
 762                 if (needprompt) {
 763                         setprompt(2);
 764                         needprompt = 0;
 765                 }
 766                 readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
 767                                 here->eofmark, here->striptabs);
 768                 n = makename();
 769                 here->here->nhere.doc = n;
 770         }
 771 }
 772
 773 static int
 774 peektoken(void)
 775 {
 776         int t;
 777
 778         t = readtoken();
 779         tokpushback++;
 780         return (t);
 781 }
 782
 783 static int
 784 readtoken(void)
 785 {
 786         int t;
 787         struct alias *ap;
 788 #ifdef DEBUG
 789         int alreadyseen = tokpushback;
 790 #endif
 791
 792         top:
 793         t = xxreadtoken();
 794
 795         /*
 796          * eat newlines
 797          */
 798         if (checkkwd & CHKNL) {
 799                 while (t == TNL) {
 800                         parseheredoc();
 801                         t = xxreadtoken();
 802                 }
 803         }
 804
 805         /*
 806          * check for keywords and aliases
 807          */
 808         if (t == TWORD && !quoteflag)
 809         {
 810                 const char * const *pp;
 811
 812                 if (checkkwd & CHKKWD)
 813                         for (pp = parsekwd; *pp; pp++) {
 814                                 if (**pp == *wordtext && equal(*pp, wordtext))
 815                                 {
 816                                         lasttoken = t = pp - parsekwd + KWDOFFSET;
 817                                         TRACE(("keyword %s recognized\n", tokname[t]));
 818                                         goto out;
 819                                 }
 820                         }
 821                 if (checkkwd & CHKALIAS &&
 822                     (ap = lookupalias(wordtext, 1)) != NULL) {
 823                         pushstring(ap->val, strlen(ap->val), ap);
 824                         goto top;
 825                 }
 826         }
 827 out:
 828         if (t != TNOT)
 829                 checkkwd = 0;
 830
 831 #ifdef DEBUG
 832         if (!alreadyseen)
 833             TRACE(("token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 834         else
 835             TRACE(("reread token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 836 #endif
 837         return (t);
 838 }
 839
 840
 841 /*
 842  * Read the next input token.
 843  * If the token is a word, we set backquotelist to the list of cmds in
 844  *      backquotes.  We set quoteflag to true if any part of the word was
 845  *      quoted.
 846  * If the token is TREDIR, then we set redirnode to a structure containing
 847  *      the redirection.
 848  * In all cases, the variable startlinno is set to the number of the line
 849  *      on which the token starts.
 850  *
 851  * [Change comment:  here documents and internal procedures]
 852  * [Readtoken shouldn't have any arguments.  Perhaps we should make the
 853  *  word parsing code into a separate routine.  In this case, readtoken
 854  *  doesn't need to have any internal procedures, but parseword does.
 855  *  We could also make parseoperator in essence the main routine, and
 856  *  have parseword (readtoken1?) handle both words and redirection.]
 857  */
 858
 859 #define RETURN(token)   return lasttoken = token
 860
 861 static int
 862 xxreadtoken(void)
 863 {
 864         int c;
 865
 866         if (tokpushback) {
 867                 tokpushback = 0;
 868                 return lasttoken;
 869         }
 870         if (needprompt) {
 871                 setprompt(2);
 872                 needprompt = 0;
 873         }
 874         startlinno = plinno;
 875         for (;;) {      /* until token or start of word found */
 876                 c = pgetc_macro();
 877                 switch (c) {
 878                 case ' ': case '\t':
 879                         continue;
 880                 case '#':
 881                         while ((c = pgetc()) != '\n' && c != PEOF);
 882                         pungetc();
 883                         continue;
 884                 case '\\':
 885                         if (pgetc() == '\n') {
 886                                 startlinno = ++plinno;
 887                                 if (doprompt)
 888                                         setprompt(2);
 889                                 else
 890                                         setprompt(0);
 891                                 continue;
 892                         }
 893                         pungetc();
 894                         goto breakloop;
 895                 case '\n':
 896                         plinno++;
 897                         needprompt = doprompt;
 898                         RETURN(TNL);
 899                 case PEOF:
 900                         RETURN(TEOF);
 901                 case '&':
 902                         if (pgetc() == '&')
 903                                 RETURN(TAND);
 904                         pungetc();
 905                         RETURN(TBACKGND);
 906                 case '|':
 907                         if (pgetc() == '|')
 908                                 RETURN(TOR);
 909                         pungetc();
 910                         RETURN(TPIPE);
 911                 case ';':
 912                         c = pgetc();
 913                         if (c == ';')
 914                                 RETURN(TENDCASE);
 915                         else if (c == '&')
 916                                 RETURN(TFALLTHRU);
 917                         pungetc();
 918                         RETURN(TSEMI);
 919                 case '(':
 920                         RETURN(TLP);
 921                 case ')':
 922                         RETURN(TRP);
 923                 default:
 924                         goto breakloop;
 925                 }
 926         }
 927 breakloop:
 928         return readtoken1(c, BASESYNTAX, (char *)NULL, 0);
 929 #undef RETURN
 930 }
 931
 932
 933 #define MAXNEST_static 8
 934 struct tokenstate
 935 {
 936         const char *syntax; /* *SYNTAX */
 937         int parenlevel; /* levels of parentheses in arithmetic */
 938         enum tokenstate_category
 939         {
 940                 TSTATE_TOP,
 941                 TSTATE_VAR_OLD, /* ${var+-=?}, inherits dquotes */
 942                 TSTATE_VAR_NEW, /* other ${var...}, own dquote state */
 943                 TSTATE_ARITH
 944         } category;
 945 };
 946
 947
 948 /*
 949  * Called to parse command substitutions.
 950  */
 951
 952 static char *
 953 parsebackq(char *out, struct nodelist **pbqlist,
 954                 int oldstyle, int dblquote, int quoted)
 955 {
 956         struct nodelist **nlpp;
 957         union node *n;
 958         char *volatile str;
 959         struct jmploc jmploc;
 960         struct jmploc *const savehandler = handler;
 961         size_t savelen;
 962         int saveprompt;
 963         const int bq_startlinno = plinno;
 964         char *volatile ostr = NULL;
 965         struct parsefile *const savetopfile = getcurrentfile();
 966         struct heredoc *const saveheredoclist = heredoclist;
 967         struct heredoc *here;
 968
 969         str = NULL;
 970         if (setjmp(jmploc.loc)) {
 971                 popfilesupto(savetopfile);
 972                 if (str)
 973                         ckfree(str);
 974                 if (ostr)
 975                         ckfree(ostr);
 976                 heredoclist = saveheredoclist;
 977                 handler = savehandler;
 978                 if (exception == EXERROR) {
 979                         startlinno = bq_startlinno;
 980                         synerror("Error in command substitution");
 981                 }
 982                 longjmp(handler->loc, 1);
 983         }
 984         INTOFF;
 985         savelen = out - stackblock();
 986         if (savelen > 0) {
 987                 str = ckmalloc(savelen);
 988                 memcpy(str, stackblock(), savelen);
 989         }
 990         handler = &jmploc;
 991         heredoclist = NULL;
 992         INTON;
 993         if (oldstyle) {
 994                 /* We must read until the closing backquote, giving special
 995                    treatment to some slashes, and then push the string and
 996                    reread it as input, interpreting it normally.  */
 997                 char *oout;
 998                 int c;
 999                 int olen;
1000
1001
1002                 STARTSTACKSTR(oout);
1003                 for (;;) {
1004                         if (needprompt) {
1005                                 setprompt(2);
1006                                 needprompt = 0;
1007                         }
1008                         CHECKSTRSPACE(2, oout);
1009                         switch (c = pgetc()) {
1010                         case '`':
1011                                 goto done;
1012
1013                         case '\\':
1014                                 if ((c = pgetc()) == '\n') {
1015                                         plinno++;
1016                                         if (doprompt)
1017                                                 setprompt(2);
1018                                         else
1019                                                 setprompt(0);
1020                                         /*
1021                                          * If eating a newline, avoid putting
1022                                          * the newline into the new character
1023                                          * stream (via the USTPUTC after the
1024                                          * switch).
1025                                          */
1026                                         continue;
1027                                 }
1028                                 if (c != '\\' && c != '`' && c != '$'
1029                                     && (!dblquote || c != '"'))
1030                                         USTPUTC('\\', oout);
1031                                 break;
1032
1033                         case '\n':
1034                                 plinno++;
1035                                 needprompt = doprompt;
1036                                 break;
1037
1038                         case PEOF:
1039                                 startlinno = plinno;
1040                                 synerror("EOF in backquote substitution");
1041                                 break;
1042
1043                         default:
1044                                 break;
1045                         }
1046                         USTPUTC(c, oout);
1047                 }
1048 done:
1049                 USTPUTC('\0', oout);
1050                 olen = oout - stackblock();
1051                 INTOFF;
1052                 ostr = ckmalloc(olen);
1053                 memcpy(ostr, stackblock(), olen);
1054                 setinputstring(ostr, 1);
1055                 INTON;
1056         }
1057         nlpp = pbqlist;
1058         while (*nlpp)
1059                 nlpp = &(*nlpp)->next;
1060         *nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
1061         (*nlpp)->next = NULL;
1062
1063         if (oldstyle) {
1064                 saveprompt = doprompt;
1065                 doprompt = 0;
1066         }
1067
1068         n = list(0);
1069
1070         if (oldstyle) {
1071                 if (peektoken() != TEOF)
1072                         synexpect(-1);
1073                 doprompt = saveprompt;
1074         } else
1075                 consumetoken(TRP);
1076
1077         (*nlpp)->n = n;
1078         if (oldstyle) {
1079                 /*
1080                  * Start reading from old file again, ignoring any pushed back
1081                  * tokens left from the backquote parsing
1082                  */
1083                 popfile();
1084                 tokpushback = 0;
1085         }
1086         STARTSTACKSTR(out);
1087         CHECKSTRSPACE(savelen + 1, out);
1088         INTOFF;
1089         if (str) {
1090                 memcpy(out, str, savelen);
1091                 STADJUST(savelen, out);
1092                 ckfree(str);
1093                 str = NULL;
1094         }
1095         if (ostr) {
1096                 ckfree(ostr);
1097                 ostr = NULL;
1098         }
1099         here = saveheredoclist;
1100         if (here != NULL) {
1101                 while (here->next != NULL)
1102                         here = here->next;
1103                 here->next = heredoclist;
1104                 heredoclist = saveheredoclist;
1105         }
1106         handler = savehandler;
1107         INTON;
1108         if (quoted)
1109                 USTPUTC(CTLBACKQ | CTLQUOTE, out);
1110         else
1111                 USTPUTC(CTLBACKQ, out);
1112         return out;
1113 }
1114
1115
1116 /*
1117  * Called to parse a backslash escape sequence inside $'...'.
1118  * The backslash has already been read.
1119  */
1120 static char *
1121 readcstyleesc(char *out)
1122 {
1123         int c, v, i, n;
1124
1125         c = pgetc();
1126         switch (c) {
1127         case '\0':
1128                 synerror("Unterminated quoted string");
1129         case '\n':
1130                 plinno++;
1131                 if (doprompt)
1132                         setprompt(2);
1133                 else
1134                         setprompt(0);
1135                 return out;
1136         case '\\':
1137         case '\'':
1138         case '"':
1139                 v = c;
1140                 break;
1141         case 'a': v = '\a'; break;
1142         case 'b': v = '\b'; break;
1143         case 'e': v = '\033'; break;
1144         case 'f': v = '\f'; break;
1145         case 'n': v = '\n'; break;
1146         case 'r': v = '\r'; break;
1147         case 't': v = '\t'; break;
1148         case 'v': v = '\v'; break;
1149         case 'x':
1150                   v = 0;
1151                   for (;;) {
1152                           c = pgetc();
1153                           if (c >= '0' && c <= '9')
1154                                   v = (v << 4) + c - '0';
1155                           else if (c >= 'A' && c <= 'F')
1156                                   v = (v << 4) + c - 'A' + 10;
1157                           else if (c >= 'a' && c <= 'f')
1158                                   v = (v << 4) + c - 'a' + 10;
1159                           else
1160                                   break;
1161                   }
1162                   pungetc();
1163                   break;
1164         case '0': case '1': case '2': case '3':
1165         case '4': case '5': case '6': case '7':
1166                   v = c - '0';
1167                   c = pgetc();
1168                   if (c >= '0' && c <= '7') {
1169                           v <<= 3;
1170                           v += c - '0';
1171                           c = pgetc();
1172                           if (c >= '0' && c <= '7') {
1173                                   v <<= 3;
1174                                   v += c - '0';
1175                           } else
1176                                   pungetc();
1177                   } else
1178                           pungetc();
1179                   break;
1180         case 'c':
1181                   c = pgetc();
1182                   if (c < 0x3f || c > 0x7a || c == 0x60)
1183                           synerror("Bad escape sequence");
1184                   if (c == '\\' && pgetc() != '\\')
1185                           synerror("Bad escape sequence");
1186                   if (c == '?')
1187                           v = 127;
1188                   else
1189                           v = c & 0x1f;
1190                   break;
1191         case 'u':
1192         case 'U':
1193                   n = c == 'U' ? 8 : 4;
1194                   v = 0;
1195                   for (i = 0; i < n; i++) {
1196                           c = pgetc();
1197                           if (c >= '0' && c <= '9')
1198                                   v = (v << 4) + c - '0';
1199                           else if (c >= 'A' && c <= 'F')
1200                                   v = (v << 4) + c - 'A' + 10;
1201                           else if (c >= 'a' && c <= 'f')
1202                                   v = (v << 4) + c - 'a' + 10;
1203                           else
1204                                   synerror("Bad escape sequence");
1205                   }
1206                   if (v == 0 || (v >= 0xd800 && v <= 0xdfff))
1207                           synerror("Bad escape sequence");
1208                   /* We really need iconv here. */
1209                   if (initial_localeisutf8 && v > 127) {
1210                           CHECKSTRSPACE(4, out);
1211                           /*
1212                            * We cannot use wctomb() as the locale may have
1213                            * changed.
1214                            */
1215                           if (v <= 0x7ff) {
1216                                   USTPUTC(0xc0 | v >> 6, out);
1217                                   USTPUTC(0x80 | (v & 0x3f), out);
1218                                   return out;
1219                           } else if (v <= 0xffff) {
1220                                   USTPUTC(0xe0 | v >> 12, out);
1221                                   USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
1222                                   USTPUTC(0x80 | (v & 0x3f), out);
1223                                   return out;
1224                           } else if (v <= 0x10ffff) {
1225                                   USTPUTC(0xf0 | v >> 18, out);
1226                                   USTPUTC(0x80 | ((v >> 12) & 0x3f), out);
1227                                   USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
1228                                   USTPUTC(0x80 | (v & 0x3f), out);
1229                                   return out;
1230                           }
1231                   }
1232                   if (v > 127)
1233                           v = '?';
1234                   break;
1235         default:
1236                   synerror("Bad escape sequence");
1237         }
1238         v = (char)v;
1239         /*
1240          * We can't handle NUL bytes.
1241          * POSIX says we should skip till the closing quote.
1242          */
1243         if (v == '\0') {
1244                 while ((c = pgetc()) != '\'') {
1245                         if (c == '\\')
1246                                 c = pgetc();
1247                         if (c == PEOF)
1248                                 synerror("Unterminated quoted string");
1249                 }
1250                 pungetc();
1251                 return out;
1252         }
1253         if (SQSYNTAX[v] == CCTL)
1254                 USTPUTC(CTLESC, out);
1255         USTPUTC(v, out);
1256         return out;
1257 }
1258
1259
1260 /*
1261  * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
1262  * is not NULL, read a here document.  In the latter case, eofmark is the
1263  * word which marks the end of the document and striptabs is true if
1264  * leading tabs should be stripped from the document.  The argument firstc
1265  * is the first character of the input token or document.
1266  *
1267  * Because C does not have internal subroutines, I have simulated them
1268  * using goto's to implement the subroutine linkage.  The following macros
1269  * will run code that appears at the end of readtoken1.
1270  */
1271
1272 #define CHECKEND()      {goto checkend; checkend_return:;}
1273 #define PARSEREDIR()    {goto parseredir; parseredir_return:;}
1274 #define PARSESUB()      {goto parsesub; parsesub_return:;}
1275 #define PARSEARITH()    {goto parsearith; parsearith_return:;}
1276
1277 static int
1278 readtoken1(int firstc, char const *initialsyntax, const char *eofmark,
1279     int striptabs)
1280 {
1281         int c = firstc;
1282         char *out;
1283         int len;
1284         char line[EOFMARKLEN + 1];
1285         struct nodelist *bqlist;
1286         int quotef;
1287         int newvarnest;
1288         int level;
1289         int synentry;
1290         struct tokenstate state_static[MAXNEST_static];
1291         int maxnest = MAXNEST_static;
1292         struct tokenstate *state = state_static;
1293         int sqiscstyle = 0;
1294
1295         startlinno = plinno;
1296         quotef = 0;
1297         bqlist = NULL;
1298         newvarnest = 0;
1299         level = 0;
1300         state[level].syntax = initialsyntax;
1301         state[level].parenlevel = 0;
1302         state[level].category = TSTATE_TOP;
1303
1304         STARTSTACKSTR(out);
1305         loop: { /* for each line, until end of word */
1306                 CHECKEND();     /* set c to PEOF if at end of here document */
1307                 for (;;) {      /* until end of line or end of word */
1308                         CHECKSTRSPACE(4, out);  /* permit 4 calls to USTPUTC */
1309
1310                         synentry = state[level].syntax[c];
1311
1312                         switch(synentry) {
1313                         case CNL:       /* '\n' */
1314                                 if (state[level].syntax == BASESYNTAX)
1315                                         goto endword;   /* exit outer loop */
1316                                 USTPUTC(c, out);
1317                                 plinno++;
1318                                 if (doprompt)
1319                                         setprompt(2);
1320                                 else
1321                                         setprompt(0);
1322                                 c = pgetc();
1323                                 goto loop;              /* continue outer loop */
1324                         case CSBACK:
1325                                 if (sqiscstyle) {
1326                                         out = readcstyleesc(out);
1327                                         break;
1328                                 }
1329                                 /* FALLTHROUGH */
1330                         case CWORD:
1331                                 USTPUTC(c, out);
1332                                 break;
1333                         case CCTL:
1334                                 if (eofmark == NULL || initialsyntax != SQSYNTAX)
1335                                         USTPUTC(CTLESC, out);
1336                                 USTPUTC(c, out);
1337                                 break;
1338                         case CBACK:     /* backslash */
1339                                 c = pgetc();
1340                                 if (c == PEOF) {
1341                                         USTPUTC('\\', out);
1342                                         pungetc();
1343                                 } else if (c == '\n') {
1344                                         plinno++;
1345                                         if (doprompt)
1346                                                 setprompt(2);
1347                                         else
1348                                                 setprompt(0);
1349                                 } else {
1350                                         if (state[level].syntax == DQSYNTAX &&
1351                                             c != '\\' && c != '`' && c != '$' &&
1352                                             (c != '"' || (eofmark != NULL &&
1353                                                 newvarnest == 0)) &&
1354                                             (c != '}' || state[level].category != TSTATE_VAR_OLD))
1355                                                 USTPUTC('\\', out);
1356                                         if ((eofmark == NULL ||
1357                                             newvarnest > 0) &&
1358                                             state[level].syntax == BASESYNTAX)
1359                                                 USTPUTC(CTLQUOTEMARK, out);
1360                                         if (SQSYNTAX[c] == CCTL)
1361                                                 USTPUTC(CTLESC, out);
1362                                         USTPUTC(c, out);
1363                                         if ((eofmark == NULL ||
1364                                             newvarnest > 0) &&
1365                                             state[level].syntax == BASESYNTAX &&
1366                                             state[level].category == TSTATE_VAR_OLD)
1367                                                 USTPUTC(CTLQUOTEEND, out);
1368                                         quotef++;
1369                                 }
1370                                 break;
1371                         case CSQUOTE:
1372                                 USTPUTC(CTLQUOTEMARK, out);
1373                                 state[level].syntax = SQSYNTAX;
1374                                 sqiscstyle = 0;
1375                                 break;
1376                         case CDQUOTE:
1377                                 USTPUTC(CTLQUOTEMARK, out);
1378                                 state[level].syntax = DQSYNTAX;
1379                                 break;
1380                         case CENDQUOTE:
1381                                 if (eofmark != NULL && newvarnest == 0)
1382                                         USTPUTC(c, out);
1383                                 else {
1384                                         if (state[level].category == TSTATE_VAR_OLD)
1385                                                 USTPUTC(CTLQUOTEEND, out);
1386                                         state[level].syntax = BASESYNTAX;
1387                                         quotef++;
1388                                 }
1389                                 break;
1390                         case CVAR:      /* '$' */
1391                                 PARSESUB();             /* parse substitution */
1392                                 break;
1393                         case CENDVAR:   /* '}' */
1394                                 if (level > 0 &&
1395                                     ((state[level].category == TSTATE_VAR_OLD &&
1396                                       state[level].syntax ==
1397                                       state[level - 1].syntax) ||
1398                                     (state[level].category == TSTATE_VAR_NEW &&
1399                                      state[level].syntax == BASESYNTAX))) {
1400                                         if (state[level].category == TSTATE_VAR_NEW)
1401                                                 newvarnest--;
1402                                         level--;
1403                                         USTPUTC(CTLENDVAR, out);
1404                                 } else {
1405                                         USTPUTC(c, out);
1406                                 }
1407                                 break;
1408                         case CLP:       /* '(' in arithmetic */
1409                                 state[level].parenlevel++;
1410                                 USTPUTC(c, out);
1411                                 break;
1412                         case CRP:       /* ')' in arithmetic */
1413                                 if (state[level].parenlevel > 0) {
1414                                         USTPUTC(c, out);
1415                                         --state[level].parenlevel;
1416                                 } else {
1417                                         if (pgetc() == ')') {
1418                                                 if (level > 0 &&
1419                                                     state[level].category == TSTATE_ARITH) {
1420                                                         level--;
1421                                                         USTPUTC(CTLENDARI, out);
1422                                                 } else
1423                                                         USTPUTC(')', out);
1424                                         } else {
1425                                                 /*
1426                                                  * unbalanced parens
1427                                                  *  (don't 2nd guess - no error)
1428                                                  */
1429                                                 pungetc();
1430                                                 USTPUTC(')', out);
1431                                         }
1432                                 }
1433                                 break;
1434                         case CBQUOTE:   /* '`' */
1435                                 out = parsebackq(out, &bqlist, 1,
1436                                     state[level].syntax == DQSYNTAX &&
1437                                     (eofmark == NULL || newvarnest > 0),
1438                                     state[level].syntax == DQSYNTAX || state[level].syntax == ARISYNTAX);
1439                                 break;
1440                         case CEOF:
1441                                 goto endword;           /* exit outer loop */
1442                         case CIGN:
1443                                 break;
1444                         default:
1445                                 if (level == 0)
1446                                         goto endword;   /* exit outer loop */
1447                                 USTPUTC(c, out);
1448                         }
1449                         c = pgetc_macro();
1450                 }
1451         }
1452 endword:
1453         if (state[level].syntax == ARISYNTAX)
1454                 synerror("Missing '))'");
1455         if (state[level].syntax != BASESYNTAX && eofmark == NULL)
1456                 synerror("Unterminated quoted string");
1457         if (state[level].category == TSTATE_VAR_OLD ||
1458             state[level].category == TSTATE_VAR_NEW) {
1459                 startlinno = plinno;
1460                 synerror("Missing '}'");
1461         }
1462         if (state != state_static)
1463                 parser_temp_free_upto(state);
1464         USTPUTC('\0', out);
1465         len = out - stackblock();
1466         out = stackblock();
1467         if (eofmark == NULL) {
1468                 if ((c == '>' || c == '<')
1469                  && quotef == 0
1470                  && len <= 2
1471                  && (*out == '\0' || is_digit(*out))) {
1472                         PARSEREDIR();
1473                         return lasttoken = TREDIR;
1474                 } else {
1475                         pungetc();
1476                 }
1477         }
1478         quoteflag = quotef;
1479         backquotelist = bqlist;
1480         grabstackblock(len);
1481         wordtext = out;
1482         return lasttoken = TWORD;
1483 /* end of readtoken routine */
1484
1485
1486 /*
1487  * Check to see whether we are at the end of the here document.  When this
1488  * is called, c is set to the first character of the next input line.  If
1489  * we are at the end of the here document, this routine sets the c to PEOF.
1490  */
1491
1492 checkend: {
1493         if (eofmark) {
1494                 if (striptabs) {
1495                         while (c == '\t')
1496                                 c = pgetc();
1497                 }
1498                 if (c == *eofmark) {
1499                         if (pfgets(line, sizeof line) != NULL) {
1500                                 const char *p, *q;
1501
1502                                 p = line;
1503                                 for (q = eofmark + 1 ; *q && *p == *q ; p++, q++);
1504                                 if ((*p == '\0' || *p == '\n') && *q == '\0') {
1505                                         c = PEOF;
1506                                         if (*p == '\n') {
1507                                                 plinno++;
1508                                                 needprompt = doprompt;
1509                                         }
1510                                 } else {
1511                                         pushstring(line, strlen(line), NULL);
1512                                 }
1513                         }
1514                 }
1515         }
1516         goto checkend_return;
1517 }
1518
1519
1520 /*
1521  * Parse a redirection operator.  The variable "out" points to a string
1522  * specifying the fd to be redirected.  The variable "c" contains the
1523  * first character of the redirection operator.
1524  */
1525
1526 parseredir: {
1527         char fd = *out;
1528         union node *np;
1529
1530         np = (union node *)stalloc(sizeof (struct nfile));
1531         if (c == '>') {
1532                 np->nfile.fd = 1;
1533                 c = pgetc();
1534                 if (c == '>')
1535                         np->type = NAPPEND;
1536                 else if (c == '&')
1537                         np->type = NTOFD;
1538                 else if (c == '|')
1539                         np->type = NCLOBBER;
1540                 else {
1541                         np->type = NTO;
1542                         pungetc();
1543                 }
1544         } else {        /* c == '<' */
1545                 np->nfile.fd = 0;
1546                 c = pgetc();
1547                 if (c == '<') {
1548                         if (sizeof (struct nfile) != sizeof (struct nhere)) {
1549                                 np = (union node *)stalloc(sizeof (struct nhere));
1550                                 np->nfile.fd = 0;
1551                         }
1552                         np->type = NHERE;
1553                         heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
1554                         heredoc->here = np;
1555                         if ((c = pgetc()) == '-') {
1556                                 heredoc->striptabs = 1;
1557                         } else {
1558                                 heredoc->striptabs = 0;
1559                                 pungetc();
1560                         }
1561                 } else if (c == '&')
1562                         np->type = NFROMFD;
1563                 else if (c == '>')
1564                         np->type = NFROMTO;
1565                 else {
1566                         np->type = NFROM;
1567                         pungetc();
1568                 }
1569         }
1570         if (fd != '\0')
1571                 np->nfile.fd = digit_val(fd);
1572         redirnode = np;
1573         goto parseredir_return;
1574 }
1575
1576
1577 /*
1578  * Parse a substitution.  At this point, we have read the dollar sign
1579  * and nothing else.
1580  */
1581
1582 parsesub: {
1583         char buf[10];
1584         int subtype;
1585         int typeloc;
1586         int flags;
1587         char *p;
1588         static const char types[] = "}-+?=";
1589         int bracketed_name = 0; /* used to handle ${[0-9]*} variables */
1590         int linno;
1591         int length;
1592         int c1;
1593
1594         c = pgetc();
1595         if (c == '(') { /* $(command) or $((arith)) */
1596                 if (pgetc() == '(') {
1597                         PARSEARITH();
1598                 } else {
1599                         pungetc();
1600                         out = parsebackq(out, &bqlist, 0,
1601                             state[level].syntax == DQSYNTAX &&
1602                             (eofmark == NULL || newvarnest > 0),
1603                             state[level].syntax == DQSYNTAX ||
1604                             state[level].syntax == ARISYNTAX);
1605                 }
1606         } else if (c == '{' || is_name(c) || is_special(c)) {
1607                 USTPUTC(CTLVAR, out);
1608                 typeloc = out - stackblock();
1609                 USTPUTC(VSNORMAL, out);
1610                 subtype = VSNORMAL;
1611                 flags = 0;
1612                 if (c == '{') {
1613                         bracketed_name = 1;
1614                         c = pgetc();
1615                         subtype = 0;
1616                 }
1617 varname:
1618                 if (!is_eof(c) && is_name(c)) {
1619                         length = 0;
1620                         do {
1621                                 STPUTC(c, out);
1622                                 c = pgetc();
1623                                 length++;
1624                         } while (!is_eof(c) && is_in_name(c));
1625                         if (length == 6 &&
1626                             strncmp(out - length, "LINENO", length) == 0) {
1627                                 /* Replace the variable name with the
1628                                  * current line number. */
1629                                 linno = plinno;
1630                                 if (funclinno != 0)
1631                                         linno -= funclinno - 1;
1632                                 snprintf(buf, sizeof(buf), "%d", linno);
1633                                 STADJUST(-6, out);
1634                                 STPUTS(buf, out);
1635                                 flags |= VSLINENO;
1636                         }
1637                 } else if (is_digit(c)) {
1638                         if (bracketed_name) {
1639                                 do {
1640                                         STPUTC(c, out);
1641                                         c = pgetc();
1642                                 } while (is_digit(c));
1643                         } else {
1644                                 STPUTC(c, out);
1645                                 c = pgetc();
1646                         }
1647                 } else if (is_special(c)) {
1648                         c1 = c;
1649                         c = pgetc();
1650                         if (subtype == 0 && c1 == '#') {
1651                                 subtype = VSLENGTH;
1652                                 if (strchr(types, c) == NULL && c != ':' &&
1653                                     c != '#' && c != '%')
1654                                         goto varname;
1655                                 c1 = c;
1656                                 c = pgetc();
1657                                 if (c1 != '}' && c == '}') {
1658                                         pungetc();
1659                                         c = c1;
1660                                         goto varname;
1661                                 }
1662                                 pungetc();
1663                                 c = c1;
1664                                 c1 = '#';
1665                                 subtype = 0;
1666                         }
1667                         USTPUTC(c1, out);
1668                 } else {
1669                         subtype = VSERROR;
1670                         if (c == '}')
1671                                 pungetc();
1672                         else if (c == '\n' || c == PEOF)
1673                                 synerror("Unexpected end of line in substitution");
1674                         else if (BASESYNTAX[c] != CCTL)
1675                                 USTPUTC(c, out);
1676                 }
1677                 if (subtype == 0) {
1678                         switch (c) {
1679                         case ':':
1680                                 flags |= VSNUL;
1681                                 c = pgetc();
1682                                 /*FALLTHROUGH*/
1683                         default:
1684                                 p = strchr(types, c);
1685                                 if (p == NULL) {
1686                                         if (c == '\n' || c == PEOF)
1687                                                 synerror("Unexpected end of line in substitution");
1688                                         if (flags == VSNUL)
1689                                                 STPUTC(':', out);
1690                                         if (BASESYNTAX[c] != CCTL)
1691                                                 STPUTC(c, out);
1692                                         subtype = VSERROR;
1693                                 } else
1694                                         subtype = p - types + VSNORMAL;
1695                                 break;
1696                         case '%':
1697                         case '#':
1698                                 {
1699                                         int cc = c;
1700                                         subtype = c == '#' ? VSTRIMLEFT :
1701                                                              VSTRIMRIGHT;
1702                                         c = pgetc();
1703                                         if (c == cc)
1704                                                 subtype++;
1705                                         else
1706                                                 pungetc();
1707                                         break;
1708                                 }
1709                         }
1710                 } else if (subtype != VSERROR) {
1711                         if (subtype == VSLENGTH && c != '}')
1712                                 subtype = VSERROR;
1713                         pungetc();
1714                 }
1715                 STPUTC('=', out);
1716                 if (state[level].syntax == DQSYNTAX ||
1717                     state[level].syntax == ARISYNTAX)
1718                         flags |= VSQUOTE;
1719                 *(stackblock() + typeloc) = subtype | flags;
1720                 if (subtype != VSNORMAL) {
1721                         if (level + 1 >= maxnest) {
1722                                 maxnest *= 2;
1723                                 if (state == state_static) {
1724                                         state = parser_temp_alloc(
1725                                             maxnest * sizeof(*state));
1726                                         memcpy(state, state_static,
1727                                             MAXNEST_static * sizeof(*state));
1728                                 } else
1729                                         state = parser_temp_realloc(state,
1730                                             maxnest * sizeof(*state));
1731                         }
1732                         level++;
1733                         state[level].parenlevel = 0;
1734                         if (subtype == VSMINUS || subtype == VSPLUS ||
1735                             subtype == VSQUESTION || subtype == VSASSIGN) {
1736                                 /*
1737                                  * For operators that were in the Bourne shell,
1738                                  * inherit the double-quote state.
1739                                  */
1740                                 state[level].syntax = state[level - 1].syntax;
1741                                 state[level].category = TSTATE_VAR_OLD;
1742                         } else {
1743                                 /*
1744                                  * The other operators take a pattern,
1745                                  * so go to BASESYNTAX.
1746                                  * Also, ' and " are now special, even
1747                                  * in here documents.
1748                                  */
1749                                 state[level].syntax = BASESYNTAX;
1750                                 state[level].category = TSTATE_VAR_NEW;
1751                                 newvarnest++;
1752                         }
1753                 }
1754         } else if (c == '\'' && state[level].syntax == BASESYNTAX) {
1755                 /* $'cstylequotes' */
1756                 USTPUTC(CTLQUOTEMARK, out);
1757                 state[level].syntax = SQSYNTAX;
1758                 sqiscstyle = 1;
1759         } else {
1760                 USTPUTC('$', out);
1761                 pungetc();
1762         }
1763         goto parsesub_return;
1764 }
1765
1766
1767 /*
1768  * Parse an arithmetic expansion (indicate start of one and set state)
1769  */
1770 parsearith: {
1771
1772         if (level + 1 >= maxnest) {
1773                 maxnest *= 2;
1774                 if (state == state_static) {
1775                         state = parser_temp_alloc(
1776                             maxnest * sizeof(*state));
1777                         memcpy(state, state_static,
1778                             MAXNEST_static * sizeof(*state));
1779                 } else
1780                         state = parser_temp_realloc(state,
1781                             maxnest * sizeof(*state));
1782         }
1783         level++;
1784         state[level].syntax = ARISYNTAX;
1785         state[level].parenlevel = 0;
1786         state[level].category = TSTATE_ARITH;
1787         USTPUTC(CTLARI, out);
1788         if (state[level - 1].syntax == DQSYNTAX)
1789                 USTPUTC('"',out);
1790         else
1791                 USTPUTC(' ',out);
1792         goto parsearith_return;
1793 }
1794
1795 } /* end of readtoken */
1796
1797
1798 /*
1799  * Returns true if the text contains nothing to expand (no dollar signs
1800  * or backquotes).
1801  */
1802
1803 static int
1804 noexpand(char *text)
1805 {
1806         char *p;
1807         char c;
1808
1809         p = text;
1810         while ((c = *p++) != '\0') {
1811                 if ( c == CTLQUOTEMARK)
1812                         continue;
1813                 if (c == CTLESC)
1814                         p++;
1815                 else if (BASESYNTAX[(int)c] == CCTL)
1816                         return 0;
1817         }
1818         return 1;
1819 }
1820
1821
1822 /*
1823  * Return true if the argument is a legal variable name (a letter or
1824  * underscore followed by zero or more letters, underscores, and digits).
1825  */
1826
1827 int
1828 goodname(const char *name)
1829 {
1830         const char *p;
1831
1832         p = name;
1833         if (! is_name(*p))
1834                 return 0;
1835         while (*++p) {
1836                 if (! is_in_name(*p))
1837                         return 0;
1838         }
1839         return 1;
1840 }
1841
1842
1843 int
1844 isassignment(const char *p)
1845 {
1846         if (!is_name(*p))
1847                 return 0;
1848         p++;
1849         for (;;) {
1850                 if (*p == '=')
1851                         return 1;
1852                 else if (!is_in_name(*p))
1853                         return 0;
1854                 p++;
1855         }
1856 }
1857
1858
1859 static void
1860 consumetoken(int token)
1861 {
1862         if (readtoken() != token)
1863                 synexpect(token);
1864 }
1865
1866
1867 /*
1868  * Called when an unexpected token is read during the parse.  The argument
1869  * is the token that is expected, or -1 if more than one type of token can
1870  * occur at this point.
1871  */
1872
1873 static void
1874 synexpect(int token)
1875 {
1876         char msg[64];
1877
1878         if (token >= 0) {
1879                 fmtstr(msg, 64, "%s unexpected (expecting %s)",
1880                         tokname[lasttoken], tokname[token]);
1881         } else {
1882                 fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
1883         }
1884         synerror(msg);
1885 }
1886
1887
1888 static void
1889 synerror(const char *msg)
1890 {
1891         if (commandname)
1892                 outfmt(out2, "%s: %d: ", commandname, startlinno);
1893         outfmt(out2, "Syntax error: %s\n", msg);
1894         error((char *)NULL);
1895 }
1896
1897 static void
1898 setprompt(int which)
1899 {
1900         whichprompt = which;
1901
1902 #ifndef NO_HISTORY
1903         if (!el)
1904 #endif
1905         {
1906                 out2str(getprompt(NULL));
1907                 flushout(out2);
1908         }
1909 }
1910
1911 /*
1912  * called by editline -- any expansions to the prompt
1913  *    should be added here.
1914  */
1915 char *
1916 getprompt(void *unused __unused)
1917 {
1918         static char ps[PROMPTLEN];
1919         char *fmt;
1920         const char *pwd;
1921         int i, trim;
1922         static char internal_error[] = "??";
1923
1924         /*
1925          * Select prompt format.
1926          */
1927         switch (whichprompt) {
1928         case 0:
1929                 fmt = nullstr;
1930                 break;
1931         case 1:
1932                 fmt = ps1val();
1933                 break;
1934         case 2:
1935                 fmt = ps2val();
1936                 break;
1937         default:
1938                 return internal_error;
1939         }
1940
1941         /*
1942          * Format prompt string.
1943          */
1944         for (i = 0; (i < 127) && (*fmt != '\0'); i++, fmt++)
1945                 if (*fmt == '\\')
1946                         switch (*++fmt) {
1947
1948                                 /*
1949                                  * Hostname.
1950                                  *
1951                                  * \h specifies just the local hostname,
1952                                  * \H specifies fully-qualified hostname.
1953                                  */
1954                         case 'h':
1955                         case 'H':
1956                                 ps[i] = '\0';
1957                                 gethostname(&ps[i], PROMPTLEN - i);
1958                                 /* Skip to end of hostname. */
1959                                 trim = (*fmt == 'h') ? '.' : '\0';
1960                                 while ((ps[i+1] != '\0') && (ps[i+1] != trim))
1961                                         i++;
1962                                 break;
1963
1964                                 /*
1965                                  * Working directory.
1966                                  *
1967                                  * \W specifies just the final component,
1968                                  * \w specifies the entire path.
1969                                  */
1970                         case 'W':
1971                         case 'w':
1972                                 pwd = lookupvar("PWD");
1973                                 if (pwd == NULL)
1974                                         pwd = "?";
1975                                 if (*fmt == 'W' &&
1976                                     *pwd == '/' && pwd[1] != '\0')
1977                                         strlcpy(&ps[i], strrchr(pwd, '/') + 1,
1978                                             PROMPTLEN - i);
1979                                 else
1980                                         strlcpy(&ps[i], pwd, PROMPTLEN - i);
1981                                 /* Skip to end of path. */
1982                                 while (ps[i + 1] != '\0')
1983                                         i++;
1984                                 break;
1985
1986                                 /*
1987                                  * Superuser status.
1988                                  *
1989                                  * '$' for normal users, '#' for root.
1990                                  */
1991                         case '$':
1992                                 ps[i] = (geteuid() != 0) ? '$' : '#';
1993                                 break;
1994
1995                                 /*
1996                                  * A literal \.
1997                                  */
1998                         case '\\':
1999                                 ps[i] = '\\';
2000                                 break;
2001
2002                                 /*
2003                                  * Emit unrecognized formats verbatim.
2004                                  */
2005                         default:
2006                                 ps[i++] = '\\';
2007                                 ps[i] = *fmt;
2008                                 break;
2009                         }
2010                 else
2011                         ps[i] = *fmt;
2012         ps[i] = '\0';
2013         return (ps);
2014 }
2015
2016
2017 const char *
2018 expandstr(const char *ps)
2019 {
2020         union node n;
2021         struct jmploc jmploc;
2022         struct jmploc *const savehandler = handler;
2023         const int saveprompt = doprompt;
2024         struct parsefile *const savetopfile = getcurrentfile();
2025         struct parser_temp *const saveparser_temp = parser_temp;
2026         const char *result = NULL;
2027
2028         if (!setjmp(jmploc.loc)) {
2029                 handler = &jmploc;
2030                 parser_temp = NULL;
2031                 setinputstring(ps, 1);
2032                 doprompt = 0;
2033                 readtoken1(pgetc(), DQSYNTAX, "\n\n", 0);
2034                 if (backquotelist != NULL)
2035                         error("Command substitution not allowed here");
2036
2037                 n.narg.type = NARG;
2038                 n.narg.next = NULL;
2039                 n.narg.text = wordtext;
2040                 n.narg.backquote = backquotelist;
2041
2042                 expandarg(&n, NULL, 0);
2043                 result = stackblock();
2044                 INTOFF;
2045         }
2046         handler = savehandler;
2047         doprompt = saveprompt;
2048         popfilesupto(savetopfile);
2049         if (parser_temp != saveparser_temp) {
2050                 parser_temp_free_all();
2051                 parser_temp = saveparser_temp;
2052         }
2053         if (result != NULL) {
2054                 INTON;
2055         } else if (exception == EXINT)
2056                 raise(SIGINT);
2057         return result;
2058 }