bin/sh/parser.c

   1 /*      $NetBSD: parser.c,v 1.93 2014/08/29 09:35:19 christos Exp $     */
   2
   3 /*-
   4  * Copyright (c) 1991, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Kenneth Almquist.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include <sys/cdefs.h>
  36 #ifndef lint
  37 #if 0
  38 static char sccsid[] = "@(#)parser.c    8.7 (Berkeley) 5/16/95";
  39 #else
  40 __RCSID("$NetBSD: parser.c,v 1.93 2014/08/29 09:35:19 christos Exp $");
  41 #endif
  42 #endif /* not lint */
  43
  44 #include <stdio.h>
  45 #include <stdlib.h>
  46 #include <limits.h>
  47
  48 #include "shell.h"
  49 #include "parser.h"
  50 #include "nodes.h"
  51 #include "expand.h"     /* defines rmescapes() */
  52 #include "eval.h"       /* defines commandname */
  53 #include "redir.h"      /* defines copyfd() */
  54 #include "syntax.h"
  55 #include "options.h"
  56 #include "input.h"
  57 #include "output.h"
  58 #include "var.h"
  59 #include "error.h"
  60 #include "memalloc.h"
  61 #include "mystring.h"
  62 #include "alias.h"
  63 #include "show.h"
  64 #ifndef SMALL
  65 #include "myhistedit.h"
  66 #endif
  67
  68 /*
  69  * Shell command parser.
  70  */
  71
  72 #define EOFMARKLEN 79
  73
  74 /* values returned by readtoken */
  75 #include "token.h"
  76
  77 #define OPENBRACE '{'
  78 #define CLOSEBRACE '}'
  79
  80
  81 struct heredoc {
  82         struct heredoc *next;   /* next here document in list */
  83         union node *here;               /* redirection node */
  84         char *eofmark;          /* string indicating end of input */
  85         int striptabs;          /* if set, strip leading tabs */
  86 };
  87
  88
  89
  90 static int noalias = 0;         /* when set, don't handle aliases */
  91 struct heredoc *heredoclist;    /* list of here documents to read */
  92 int parsebackquote;             /* nonzero if we are inside backquotes */
  93 int doprompt;                   /* if set, prompt the user */
  94 int needprompt;                 /* true if interactive and at start of line */
  95 int lasttoken;                  /* last token read */
  96 MKINIT int tokpushback;         /* last token pushed back */
  97 char *wordtext;                 /* text of last word returned by readtoken */
  98 MKINIT int checkkwd;            /* 1 == check for kwds, 2 == also eat newlines */
  99 struct nodelist *backquotelist;
 100 union node *redirnode;
 101 struct heredoc *heredoc;
 102 int quoteflag;                  /* set if (part of) last token was quoted */
 103 int startlinno;                 /* line # where last token started */
 104 int funclinno;                  /* line # where the current function started */
 105
 106
 107 STATIC union node *list(int, int);
 108 STATIC union node *andor(void);
 109 STATIC union node *pipeline(void);
 110 STATIC union node *command(void);
 111 STATIC union node *simplecmd(union node **, union node *);
 112 STATIC union node *makename(void);
 113 STATIC void parsefname(void);
 114 STATIC void parseheredoc(void);
 115 STATIC int peektoken(void);
 116 STATIC int readtoken(void);
 117 STATIC int xxreadtoken(void);
 118 STATIC int readtoken1(int, char const *, char *, int);
 119 STATIC int noexpand(char *);
 120 STATIC void synexpect(int) __dead;
 121 STATIC void synerror(const char *) __dead;
 122 STATIC void setprompt(int);
 123
 124
 125 /*
 126  * Read and parse a command.  Returns NEOF on end of file.  (NULL is a
 127  * valid parse tree indicating a blank line.)
 128  */
 129
 130 union node *
 131 parsecmd(int interact)
 132 {
 133         int t;
 134
 135         tokpushback = 0;
 136         doprompt = interact;
 137         if (doprompt)
 138                 setprompt(1);
 139         else
 140                 setprompt(0);
 141         needprompt = 0;
 142         t = readtoken();
 143         if (t == TEOF)
 144                 return NEOF;
 145         if (t == TNL)
 146                 return NULL;
 147         tokpushback++;
 148         return list(1, 0);
 149 }
 150
 151
 152 STATIC union node *
 153 list(int nlflag, int erflag)
 154 {
 155         union node *n1, *n2, *n3;
 156         int tok;
 157         TRACE(("list: entered\n"));
 158
 159         checkkwd = 2;
 160         if (nlflag == 0 && tokendlist[peektoken()])
 161                 return NULL;
 162         n1 = NULL;
 163         for (;;) {
 164                 n2 = andor();
 165                 tok = readtoken();
 166                 if (tok == TBACKGND) {
 167                         if (n2->type == NCMD || n2->type == NPIPE) {
 168                                 n2->ncmd.backgnd = 1;
 169                         } else if (n2->type == NREDIR) {
 170                                 n2->type = NBACKGND;
 171                         } else {
 172                                 n3 = (union node *)stalloc(sizeof (struct nredir));
 173                                 n3->type = NBACKGND;
 174                                 n3->nredir.n = n2;
 175                                 n3->nredir.redirect = NULL;
 176                                 n2 = n3;
 177                         }
 178                 }
 179                 if (n1 == NULL) {
 180                         n1 = n2;
 181                 }
 182                 else {
 183                         n3 = (union node *)stalloc(sizeof (struct nbinary));
 184                         n3->type = NSEMI;
 185                         n3->nbinary.ch1 = n1;
 186                         n3->nbinary.ch2 = n2;
 187                         n1 = n3;
 188                 }
 189                 switch (tok) {
 190                 case TBACKGND:
 191                 case TSEMI:
 192                         tok = readtoken();
 193                         /* fall through */
 194                 case TNL:
 195                         if (tok == TNL) {
 196                                 parseheredoc();
 197                                 if (nlflag)
 198                                         return n1;
 199                         } else {
 200                                 tokpushback++;
 201                         }
 202                         checkkwd = 2;
 203                         if (tokendlist[peektoken()])
 204                                 return n1;
 205                         break;
 206                 case TEOF:
 207                         if (heredoclist)
 208                                 parseheredoc();
 209                         else
 210                                 pungetc();              /* push back EOF on input */
 211                         return n1;
 212                 default:
 213                         if (nlflag || erflag)
 214                                 synexpect(-1);
 215                         tokpushback++;
 216                         return n1;
 217                 }
 218         }
 219 }
 220
 221
 222
 223 STATIC union node *
 224 andor(void)
 225 {
 226         union node *n1, *n2, *n3;
 227         int t;
 228
 229         TRACE(("andor: entered\n"));
 230         n1 = pipeline();
 231         for (;;) {
 232                 if ((t = readtoken()) == TAND) {
 233                         t = NAND;
 234                 } else if (t == TOR) {
 235                         t = NOR;
 236                 } else {
 237                         tokpushback++;
 238                         return n1;
 239                 }
 240                 n2 = pipeline();
 241                 n3 = (union node *)stalloc(sizeof (struct nbinary));
 242                 n3->type = t;
 243                 n3->nbinary.ch1 = n1;
 244                 n3->nbinary.ch2 = n2;
 245                 n1 = n3;
 246         }
 247 }
 248
 249
 250
 251 STATIC union node *
 252 pipeline(void)
 253 {
 254         union node *n1, *n2, *pipenode;
 255         struct nodelist *lp, *prev;
 256         int negate;
 257
 258         TRACE(("pipeline: entered\n"));
 259
 260         negate = 0;
 261         checkkwd = 2;
 262         while (readtoken() == TNOT) {
 263                 TRACE(("pipeline: TNOT recognized\n"));
 264                 negate = !negate;
 265         }
 266         tokpushback++;
 267         n1 = command();
 268         if (readtoken() == TPIPE) {
 269                 pipenode = (union node *)stalloc(sizeof (struct npipe));
 270                 pipenode->type = NPIPE;
 271                 pipenode->npipe.backgnd = 0;
 272                 lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 273                 pipenode->npipe.cmdlist = lp;
 274                 lp->n = n1;
 275                 do {
 276                         prev = lp;
 277                         lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 278                         lp->n = command();
 279                         prev->next = lp;
 280                 } while (readtoken() == TPIPE);
 281                 lp->next = NULL;
 282                 n1 = pipenode;
 283         }
 284         tokpushback++;
 285         if (negate) {
 286                 TRACE(("negate pipeline\n"));
 287                 n2 = (union node *)stalloc(sizeof (struct nnot));
 288                 n2->type = NNOT;
 289                 n2->nnot.com = n1;
 290                 return n2;
 291         } else
 292                 return n1;
 293 }
 294
 295
 296
 297 STATIC union node *
 298 command(void)
 299 {
 300         union node *n1, *n2;
 301         union node *ap, **app;
 302         union node *cp, **cpp;
 303         union node *redir, **rpp;
 304         int t, negate = 0;
 305
 306         TRACE(("command: entered\n"));
 307
 308         checkkwd = 2;
 309         redir = NULL;
 310         n1 = NULL;
 311         rpp = &redir;
 312
 313         /* Check for redirection which may precede command */
 314         while (readtoken() == TREDIR) {
 315                 *rpp = n2 = redirnode;
 316                 rpp = &n2->nfile.next;
 317                 parsefname();
 318         }
 319         tokpushback++;
 320
 321         while (readtoken() == TNOT) {
 322                 TRACE(("command: TNOT recognized\n"));
 323                 negate = !negate;
 324         }
 325         tokpushback++;
 326
 327         switch (readtoken()) {
 328         case TIF:
 329                 n1 = (union node *)stalloc(sizeof (struct nif));
 330                 n1->type = NIF;
 331                 n1->nif.test = list(0, 0);
 332                 if (readtoken() != TTHEN)
 333                         synexpect(TTHEN);
 334                 n1->nif.ifpart = list(0, 0);
 335                 n2 = n1;
 336                 while (readtoken() == TELIF) {
 337                         n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
 338                         n2 = n2->nif.elsepart;
 339                         n2->type = NIF;
 340                         n2->nif.test = list(0, 0);
 341                         if (readtoken() != TTHEN)
 342                                 synexpect(TTHEN);
 343                         n2->nif.ifpart = list(0, 0);
 344                 }
 345                 if (lasttoken == TELSE)
 346                         n2->nif.elsepart = list(0, 0);
 347                 else {
 348                         n2->nif.elsepart = NULL;
 349                         tokpushback++;
 350                 }
 351                 if (readtoken() != TFI)
 352                         synexpect(TFI);
 353                 checkkwd = 1;
 354                 break;
 355         case TWHILE:
 356         case TUNTIL: {
 357                 int got;
 358                 n1 = (union node *)stalloc(sizeof (struct nbinary));
 359                 n1->type = (lasttoken == TWHILE)? NWHILE : NUNTIL;
 360                 n1->nbinary.ch1 = list(0, 0);
 361                 if ((got=readtoken()) != TDO) {
 362 TRACE(("expecting DO got %s %s\n", tokname[got], got == TWORD ? wordtext : ""));
 363                         synexpect(TDO);
 364                 }
 365                 n1->nbinary.ch2 = list(0, 0);
 366                 if (readtoken() != TDONE)
 367                         synexpect(TDONE);
 368                 checkkwd = 1;
 369                 break;
 370         }
 371         case TFOR:
 372                 if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
 373                         synerror("Bad for loop variable");
 374                 n1 = (union node *)stalloc(sizeof (struct nfor));
 375                 n1->type = NFOR;
 376                 n1->nfor.var = wordtext;
 377                 if (readtoken() == TWORD && ! quoteflag && equal(wordtext, "in")) {
 378                         app = &ap;
 379                         while (readtoken() == TWORD) {
 380                                 n2 = (union node *)stalloc(sizeof (struct narg));
 381                                 n2->type = NARG;
 382                                 n2->narg.text = wordtext;
 383                                 n2->narg.backquote = backquotelist;
 384                                 *app = n2;
 385                                 app = &n2->narg.next;
 386                         }
 387                         *app = NULL;
 388                         n1->nfor.args = ap;
 389                         if (lasttoken != TNL && lasttoken != TSEMI)
 390                                 synexpect(-1);
 391                 } else {
 392                         static char argvars[5] = {CTLVAR, VSNORMAL|VSQUOTE,
 393                                                                    '@', '=', '\0'};
 394                         n2 = (union node *)stalloc(sizeof (struct narg));
 395                         n2->type = NARG;
 396                         n2->narg.text = argvars;
 397                         n2->narg.backquote = NULL;
 398                         n2->narg.next = NULL;
 399                         n1->nfor.args = n2;
 400                         /*
 401                          * Newline or semicolon here is optional (but note
 402                          * that the original Bourne shell only allowed NL).
 403                          */
 404                         if (lasttoken != TNL && lasttoken != TSEMI)
 405                                 tokpushback++;
 406                 }
 407                 checkkwd = 2;
 408                 if ((t = readtoken()) == TDO)
 409                         t = TDONE;
 410                 else if (t == TBEGIN)
 411                         t = TEND;
 412                 else
 413                         synexpect(-1);
 414                 n1->nfor.body = list(0, 0);
 415                 if (readtoken() != t)
 416                         synexpect(t);
 417                 checkkwd = 1;
 418                 break;
 419         case TCASE:
 420                 n1 = (union node *)stalloc(sizeof (struct ncase));
 421                 n1->type = NCASE;
 422                 if (readtoken() != TWORD)
 423                         synexpect(TWORD);
 424                 n1->ncase.expr = n2 = (union node *)stalloc(sizeof (struct narg));
 425                 n2->type = NARG;
 426                 n2->narg.text = wordtext;
 427                 n2->narg.backquote = backquotelist;
 428                 n2->narg.next = NULL;
 429                 while (readtoken() == TNL);
 430                 if (lasttoken != TWORD || ! equal(wordtext, "in"))
 431                         synerror("expecting \"in\"");
 432                 cpp = &n1->ncase.cases;
 433                 noalias = 1;
 434                 checkkwd = 2, readtoken();
 435                 /*
 436                  * Both ksh and bash accept 'case x in esac'
 437                  * so configure scripts started taking advantage of this.
 438                  * The page: http://pubs.opengroup.org/onlinepubs/\
 439                  * 009695399/utilities/xcu_chap02.html contradicts itself,
 440                  * as to if this is legal; the "Case Conditional Format"
 441                  * paragraph shows one case is required, but the "Grammar"
 442                  * section shows a grammar that explicitly allows the no
 443                  * case option.
 444                  */
 445                 while (lasttoken != TESAC) {
 446                         *cpp = cp = (union node *)stalloc(sizeof (struct nclist));
 447                         if (lasttoken == TLP)
 448                                 readtoken();
 449                         cp->type = NCLIST;
 450                         app = &cp->nclist.pattern;
 451                         for (;;) {
 452                                 *app = ap = (union node *)stalloc(sizeof (struct narg));
 453                                 ap->type = NARG;
 454                                 ap->narg.text = wordtext;
 455                                 ap->narg.backquote = backquotelist;
 456                                 if (checkkwd = 2, readtoken() != TPIPE)
 457                                         break;
 458                                 app = &ap->narg.next;
 459                                 readtoken();
 460                         }
 461                         ap->narg.next = NULL;
 462                         noalias = 0;
 463                         if (lasttoken != TRP) {
 464                                 synexpect(TRP);
 465                         }
 466                         cp->nclist.body = list(0, 0);
 467
 468                         checkkwd = 2;
 469                         if ((t = readtoken()) != TESAC) {
 470                                 if (t != TENDCASE) {
 471                                         noalias = 0;
 472                                         synexpect(TENDCASE);
 473                                 } else {
 474                                         noalias = 1;
 475                                         checkkwd = 2;
 476                                         readtoken();
 477                                 }
 478                         }
 479                         cpp = &cp->nclist.next;
 480                 }
 481                 noalias = 0;
 482                 *cpp = NULL;
 483                 checkkwd = 1;
 484                 break;
 485         case TLP:
 486                 n1 = (union node *)stalloc(sizeof (struct nredir));
 487                 n1->type = NSUBSHELL;
 488                 n1->nredir.n = list(0, 0);
 489                 n1->nredir.redirect = NULL;
 490                 if (readtoken() != TRP)
 491                         synexpect(TRP);
 492                 checkkwd = 1;
 493                 break;
 494         case TBEGIN:
 495                 n1 = list(0, 0);
 496                 if (readtoken() != TEND)
 497                         synexpect(TEND);
 498                 checkkwd = 1;
 499                 break;
 500         /* Handle an empty command like other simple commands.  */
 501         case TSEMI:
 502                 /*
 503                  * An empty command before a ; doesn't make much sense, and
 504                  * should certainly be disallowed in the case of `if ;'.
 505                  */
 506                 if (!redir)
 507                         synexpect(-1);
 508         case TAND:
 509         case TOR:
 510         case TNL:
 511         case TEOF:
 512         case TWORD:
 513         case TRP:
 514                 tokpushback++;
 515                 n1 = simplecmd(rpp, redir);
 516                 goto checkneg;
 517         default:
 518                 synexpect(-1);
 519                 /* NOTREACHED */
 520         }
 521
 522         /* Now check for redirection which may follow command */
 523         while (readtoken() == TREDIR) {
 524                 *rpp = n2 = redirnode;
 525                 rpp = &n2->nfile.next;
 526                 parsefname();
 527         }
 528         tokpushback++;
 529         *rpp = NULL;
 530         if (redir) {
 531                 if (n1->type != NSUBSHELL) {
 532                         n2 = (union node *)stalloc(sizeof (struct nredir));
 533                         n2->type = NREDIR;
 534                         n2->nredir.n = n1;
 535                         n1 = n2;
 536                 }
 537                 n1->nredir.redirect = redir;
 538         }
 539
 540 checkneg:
 541         if (negate) {
 542                 TRACE(("negate command\n"));
 543                 n2 = (union node *)stalloc(sizeof (struct nnot));
 544                 n2->type = NNOT;
 545                 n2->nnot.com = n1;
 546                 return n2;
 547         }
 548         else
 549                 return n1;
 550 }
 551
 552
 553 STATIC union node *
 554 simplecmd(union node **rpp, union node *redir)
 555 {
 556         union node *args, **app;
 557         union node **orig_rpp = rpp;
 558         union node *n = NULL, *n2;
 559         int negate = 0;
 560
 561         /* If we don't have any redirections already, then we must reset */
 562         /* rpp to be the address of the local redir variable.  */
 563         if (redir == 0)
 564                 rpp = &redir;
 565
 566         args = NULL;
 567         app = &args;
 568         /*
 569          * We save the incoming value, because we need this for shell
 570          * functions.  There can not be a redirect or an argument between
 571          * the function name and the open parenthesis.
 572          */
 573         orig_rpp = rpp;
 574
 575         while (readtoken() == TNOT) {
 576                 TRACE(("simplcmd: TNOT recognized\n"));
 577                 negate = !negate;
 578         }
 579         tokpushback++;
 580
 581         for (;;) {
 582                 if (readtoken() == TWORD) {
 583                         n = (union node *)stalloc(sizeof (struct narg));
 584                         n->type = NARG;
 585                         n->narg.text = wordtext;
 586                         n->narg.backquote = backquotelist;
 587                         *app = n;
 588                         app = &n->narg.next;
 589                 } else if (lasttoken == TREDIR) {
 590                         *rpp = n = redirnode;
 591                         rpp = &n->nfile.next;
 592                         parsefname();   /* read name of redirection file */
 593                 } else if (lasttoken == TLP && app == &args->narg.next
 594                                             && rpp == orig_rpp) {
 595                         /* We have a function */
 596                         if (readtoken() != TRP)
 597                                 synexpect(TRP);
 598                         funclinno = plinno;
 599                         rmescapes(n->narg.text);
 600                         if (!goodname(n->narg.text))
 601                                 synerror("Bad function name");
 602                         n->type = NDEFUN;
 603                         n->narg.next = command();
 604                         funclinno = 0;
 605                         goto checkneg;
 606                 } else {
 607                         tokpushback++;
 608                         break;
 609                 }
 610         }
 611         *app = NULL;
 612         *rpp = NULL;
 613         n = (union node *)stalloc(sizeof (struct ncmd));
 614         n->type = NCMD;
 615         n->ncmd.backgnd = 0;
 616         n->ncmd.args = args;
 617         n->ncmd.redirect = redir;
 618
 619 checkneg:
 620         if (negate) {
 621                 TRACE(("negate simplecmd\n"));
 622                 n2 = (union node *)stalloc(sizeof (struct nnot));
 623                 n2->type = NNOT;
 624                 n2->nnot.com = n;
 625                 return n2;
 626         }
 627         else
 628                 return n;
 629 }
 630
 631 STATIC union node *
 632 makename(void)
 633 {
 634         union node *n;
 635
 636         n = (union node *)stalloc(sizeof (struct narg));
 637         n->type = NARG;
 638         n->narg.next = NULL;
 639         n->narg.text = wordtext;
 640         n->narg.backquote = backquotelist;
 641         return n;
 642 }
 643
 644 void fixredir(union node *n, const char *text, int err)
 645         {
 646         TRACE(("Fix redir %s %d\n", text, err));
 647         if (!err)
 648                 n->ndup.vname = NULL;
 649
 650         if (is_number(text))
 651                 n->ndup.dupfd = number(text);
 652         else if (text[0] == '-' && text[1] == '\0')
 653                 n->ndup.dupfd = -1;
 654         else {
 655
 656                 if (err)
 657                         synerror("Bad fd number");
 658                 else
 659                         n->ndup.vname = makename();
 660         }
 661 }
 662
 663
 664 STATIC void
 665 parsefname(void)
 666 {
 667         union node *n = redirnode;
 668
 669         if (readtoken() != TWORD)
 670                 synexpect(-1);
 671         if (n->type == NHERE) {
 672                 struct heredoc *here = heredoc;
 673                 struct heredoc *p;
 674                 int i;
 675
 676                 if (quoteflag == 0)
 677                         n->type = NXHERE;
 678                 TRACE(("Here document %d\n", n->type));
 679                 if (here->striptabs) {
 680                         while (*wordtext == '\t')
 681                                 wordtext++;
 682                 }
 683                 if (! noexpand(wordtext) || (i = strlen(wordtext)) == 0 || i > EOFMARKLEN)
 684                         synerror("Illegal eof marker for << redirection");
 685                 rmescapes(wordtext);
 686                 here->eofmark = wordtext;
 687                 here->next = NULL;
 688                 if (heredoclist == NULL)
 689                         heredoclist = here;
 690                 else {
 691                         for (p = heredoclist ; p->next ; p = p->next)
 692                                 continue;
 693                         p->next = here;
 694                 }
 695         } else if (n->type == NTOFD || n->type == NFROMFD) {
 696                 fixredir(n, wordtext, 0);
 697         } else {
 698                 n->nfile.fname = makename();
 699         }
 700 }
 701
 702
 703 /*
 704  * Input any here documents.
 705  */
 706
 707 STATIC void
 708 parseheredoc(void)
 709 {
 710         struct heredoc *here;
 711         union node *n;
 712
 713         while (heredoclist) {
 714                 here = heredoclist;
 715                 heredoclist = here->next;
 716                 if (needprompt) {
 717                         setprompt(2);
 718                         needprompt = 0;
 719                 }
 720                 readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
 721                                 here->eofmark, here->striptabs);
 722                 n = (union node *)stalloc(sizeof (struct narg));
 723                 n->narg.type = NARG;
 724                 n->narg.next = NULL;
 725                 n->narg.text = wordtext;
 726                 n->narg.backquote = backquotelist;
 727                 here->here->nhere.doc = n;
 728         }
 729 }
 730
 731 STATIC int
 732 peektoken(void)
 733 {
 734         int t;
 735
 736         t = readtoken();
 737         tokpushback++;
 738         return (t);
 739 }
 740
 741 STATIC int
 742 readtoken(void)
 743 {
 744         int t;
 745         int savecheckkwd = checkkwd;
 746 #ifdef DEBUG
 747         int alreadyseen = tokpushback;
 748 #endif
 749         struct alias *ap;
 750
 751         top:
 752         t = xxreadtoken();
 753
 754         if (checkkwd) {
 755                 /*
 756                  * eat newlines
 757                  */
 758                 if (checkkwd == 2) {
 759                         checkkwd = 0;
 760                         while (t == TNL) {
 761                                 parseheredoc();
 762                                 t = xxreadtoken();
 763                         }
 764                 } else
 765                         checkkwd = 0;
 766                 /*
 767                  * check for keywords and aliases
 768                  */
 769                 if (t == TWORD && !quoteflag)
 770                 {
 771                         const char *const *pp;
 772
 773                         for (pp = parsekwd; *pp; pp++) {
 774                                 if (**pp == *wordtext && equal(*pp, wordtext))
 775                                 {
 776                                         lasttoken = t = pp -
 777                                             parsekwd + KWDOFFSET;
 778                                         TRACE(("keyword %s recognized\n", tokname[t]));
 779                                         goto out;
 780                                 }
 781                         }
 782                         if (!noalias &&
 783                             (ap = lookupalias(wordtext, 1)) != NULL) {
 784                                 pushstring(ap->val, strlen(ap->val), ap);
 785                                 checkkwd = savecheckkwd;
 786                                 goto top;
 787                         }
 788                 }
 789 out:
 790                 checkkwd = (t == TNOT) ? savecheckkwd : 0;
 791         }
 792         TRACE(("%stoken %s %s\n", alreadyseen ? "reread " : "", tokname[t], t == TWORD ? wordtext : ""));
 793         return (t);
 794 }
 795
 796
 797 /*
 798  * Read the next input token.
 799  * If the token is a word, we set backquotelist to the list of cmds in
 800  *      backquotes.  We set quoteflag to true if any part of the word was
 801  *      quoted.
 802  * If the token is TREDIR, then we set redirnode to a structure containing
 803  *      the redirection.
 804  * In all cases, the variable startlinno is set to the number of the line
 805  *      on which the token starts.
 806  *
 807  * [Change comment:  here documents and internal procedures]
 808  * [Readtoken shouldn't have any arguments.  Perhaps we should make the
 809  *  word parsing code into a separate routine.  In this case, readtoken
 810  *  doesn't need to have any internal procedures, but parseword does.
 811  *  We could also make parseoperator in essence the main routine, and
 812  *  have parseword (readtoken1?) handle both words and redirection.]
 813  */
 814
 815 #define RETURN(token)   return lasttoken = token
 816
 817 STATIC int
 818 xxreadtoken(void)
 819 {
 820         int c;
 821
 822         if (tokpushback) {
 823                 tokpushback = 0;
 824                 return lasttoken;
 825         }
 826         if (needprompt) {
 827                 setprompt(2);
 828                 needprompt = 0;
 829         }
 830         startlinno = plinno;
 831         for (;;) {      /* until token or start of word found */
 832                 c = pgetc_macro();
 833                 switch (c) {
 834                 case ' ': case '\t':
 835                         continue;
 836                 case '#':
 837                         while ((c = pgetc()) != '\n' && c != PEOF)
 838                                 continue;
 839                         pungetc();
 840                         continue;
 841                 case '\\':
 842                         switch (pgetc()) {
 843                         case '\n':
 844                                 startlinno = ++plinno;
 845                                 if (doprompt)
 846                                         setprompt(2);
 847                                 else
 848                                         setprompt(0);
 849                                 continue;
 850                         case PEOF:
 851                                 RETURN(TEOF);
 852                         default:
 853                                 pungetc();
 854                                 break;
 855                         }
 856                         goto breakloop;
 857                 case '\n':
 858                         plinno++;
 859                         needprompt = doprompt;
 860                         RETURN(TNL);
 861                 case PEOF:
 862                         RETURN(TEOF);
 863                 case '&':
 864                         if (pgetc() == '&')
 865                                 RETURN(TAND);
 866                         pungetc();
 867                         RETURN(TBACKGND);
 868                 case '|':
 869                         if (pgetc() == '|')
 870                                 RETURN(TOR);
 871                         pungetc();
 872                         RETURN(TPIPE);
 873                 case ';':
 874                         if (pgetc() == ';')
 875                                 RETURN(TENDCASE);
 876                         pungetc();
 877                         RETURN(TSEMI);
 878                 case '(':
 879                         RETURN(TLP);
 880                 case ')':
 881                         RETURN(TRP);
 882                 default:
 883                         goto breakloop;
 884                 }
 885         }
 886 breakloop:
 887         return readtoken1(c, BASESYNTAX, NULL, 0);
 888 #undef RETURN
 889 }
 890
 891
 892
 893 /*
 894  * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
 895  * is not NULL, read a here document.  In the latter case, eofmark is the
 896  * word which marks the end of the document and striptabs is true if
 897  * leading tabs should be stripped from the document.  The argument firstc
 898  * is the first character of the input token or document.
 899  *
 900  * Because C does not have internal subroutines, I have simulated them
 901  * using goto's to implement the subroutine linkage.  The following macros
 902  * will run code that appears at the end of readtoken1.
 903  */
 904
 905 #define CHECKEND()      {goto checkend; checkend_return:;}
 906 #define PARSEREDIR()    {goto parseredir; parseredir_return:;}
 907 #define PARSESUB()      {goto parsesub; parsesub_return:;}
 908 #define PARSEBACKQOLD() {oldstyle = 1; goto parsebackq; parsebackq_oldreturn:;}
 909 #define PARSEBACKQNEW() {oldstyle = 0; goto parsebackq; parsebackq_newreturn:;}
 910 #define PARSEARITH()    {goto parsearith; parsearith_return:;}
 911
 912 /*
 913  * Keep track of nested doublequotes in dblquote and doublequotep.
 914  * We use dblquote for the first 32 levels, and we expand to a malloc'ed
 915  * region for levels above that. Usually we never need to malloc.
 916  * This code assumes that an int is 32 bits. We don't use uint32_t,
 917  * because the rest of the code does not.
 918  */
 919 #define ISDBLQUOTE() ((varnest < 32) ? (dblquote & (1 << varnest)) : \
 920     (dblquotep[(varnest / 32) - 1] & (1 << (varnest % 32))))
 921
 922 #define SETDBLQUOTE() \
 923     if (varnest < 32) \
 924         dblquote |= (1 << varnest); \
 925     else \
 926         dblquotep[(varnest / 32) - 1] |= (1 << (varnest % 32))
 927
 928 #define CLRDBLQUOTE() \
 929     if (varnest < 32) \
 930         dblquote &= ~(1 << varnest); \
 931     else \
 932         dblquotep[(varnest / 32) - 1] &= ~(1 << (varnest % 32))
 933
 934 STATIC int
 935 readtoken1(int firstc, char const *syn, char *eofmark, int striptabs)
 936 {
 937         char const * volatile syntax = syn;
 938         int c = firstc;
 939         char * volatile out;
 940         int len;
 941         char line[EOFMARKLEN + 1];
 942         struct nodelist *bqlist;
 943         volatile int quotef;
 944         int * volatile dblquotep = NULL;
 945         volatile size_t maxnest = 32;
 946         volatile int dblquote;
 947         volatile size_t varnest;        /* levels of variables expansion */
 948         volatile int arinest;   /* levels of arithmetic expansion */
 949         volatile int parenlevel;        /* levels of parens in arithmetic */
 950         volatile int oldstyle;
 951         char const * volatile prevsyntax;       /* syntax before arithmetic */
 952 #ifdef __GNUC__
 953         prevsyntax = NULL;      /* XXX gcc4 */
 954 #endif
 955
 956         startlinno = plinno;
 957         dblquote = 0;
 958         varnest = 0;
 959         if (syntax == DQSYNTAX) {
 960                 SETDBLQUOTE();
 961         }
 962         quotef = 0;
 963         bqlist = NULL;
 964         arinest = 0;
 965         parenlevel = 0;
 966
 967         STARTSTACKSTR(out);
 968         loop: { /* for each line, until end of word */
 969 #if ATTY
 970                 if (c == '\034' && doprompt
 971                  && attyset() && ! equal(termval(), "emacs")) {
 972                         attyline();
 973                         if (syntax == BASESYNTAX)
 974                                 return readtoken();
 975                         c = pgetc();
 976                         goto loop;
 977                 }
 978 #endif
 979                 CHECKEND();     /* set c to PEOF if at end of here document */
 980                 for (;;) {      /* until end of line or end of word */
 981                         CHECKSTRSPACE(4, out);  /* permit 4 calls to USTPUTC */
 982                         switch(syntax[c]) {
 983                         case CNL:       /* '\n' */
 984                                 if (syntax == BASESYNTAX)
 985                                         goto endword;   /* exit outer loop */
 986                                 USTPUTC(c, out);
 987                                 plinno++;
 988                                 if (doprompt)
 989                                         setprompt(2);
 990                                 else
 991                                         setprompt(0);
 992                                 c = pgetc();
 993                                 goto loop;              /* continue outer loop */
 994                         case CWORD:
 995                                 USTPUTC(c, out);
 996                                 break;
 997                         case CCTL:
 998                                 if (eofmark == NULL || ISDBLQUOTE())
 999                                         USTPUTC(CTLESC, out);
1000                                 USTPUTC(c, out);
1001                                 break;
1002                         case CBACK:     /* backslash */
1003                                 c = pgetc();
1004                                 if (c == PEOF) {
1005                                         USTPUTC('\\', out);
1006                                         pungetc();
1007                                         break;
1008                                 }
1009                                 if (c == '\n') {
1010                                         plinno++;
1011                                         if (doprompt)
1012                                                 setprompt(2);
1013                                         else
1014                                                 setprompt(0);
1015                                         break;
1016                                 }
1017                                 quotef = 1;
1018                                 if (ISDBLQUOTE() && c != '\\' &&
1019                                     c != '`' && c != '$' &&
1020                                     (c != '"' || eofmark != NULL))
1021                                         USTPUTC('\\', out);
1022                                 if (SQSYNTAX[c] == CCTL)
1023                                         USTPUTC(CTLESC, out);
1024                                 else if (eofmark == NULL) {
1025                                         USTPUTC(CTLQUOTEMARK, out);
1026                                         USTPUTC(c, out);
1027                                         if (varnest != 0)
1028                                                 USTPUTC(CTLQUOTEEND, out);
1029                                         break;
1030                                 }
1031                                 USTPUTC(c, out);
1032                                 break;
1033                         case CSQUOTE:
1034                                 if (syntax != SQSYNTAX) {
1035                                         if (eofmark == NULL)
1036                                                 USTPUTC(CTLQUOTEMARK, out);
1037                                         quotef = 1;
1038                                         syntax = SQSYNTAX;
1039                                         break;
1040                                 }
1041                                 if (eofmark != NULL && arinest == 0 &&
1042                                     varnest == 0) {
1043                                         /* Ignore inside quoted here document */
1044                                         USTPUTC(c, out);
1045                                         break;
1046                                 }
1047                                 /* End of single quotes... */
1048                                 if (arinest)
1049                                         syntax = ARISYNTAX;
1050                                 else {
1051                                         syntax = BASESYNTAX;
1052                                         if (varnest != 0)
1053                                                 USTPUTC(CTLQUOTEEND, out);
1054                                 }
1055                                 break;
1056                         case CDQUOTE:
1057                                 if (eofmark != NULL && arinest == 0 &&
1058                                     varnest == 0) {
1059                                         /* Ignore inside here document */
1060                                         USTPUTC(c, out);
1061                                         break;
1062                                 }
1063                                 quotef = 1;
1064                                 if (arinest) {
1065                                         if (ISDBLQUOTE()) {
1066                                                 syntax = ARISYNTAX;
1067                                                 CLRDBLQUOTE();
1068                                         } else {
1069                                                 syntax = DQSYNTAX;
1070                                                 SETDBLQUOTE();
1071                                                 USTPUTC(CTLQUOTEMARK, out);
1072                                         }
1073                                         break;
1074                                 }
1075                                 if (eofmark != NULL)
1076                                         break;
1077                                 if (ISDBLQUOTE()) {
1078                                         if (varnest != 0)
1079                                                 USTPUTC(CTLQUOTEEND, out);
1080                                         syntax = BASESYNTAX;
1081                                         CLRDBLQUOTE();
1082                                 } else {
1083                                         syntax = DQSYNTAX;
1084                                         SETDBLQUOTE();
1085                                         USTPUTC(CTLQUOTEMARK, out);
1086                                 }
1087                                 break;
1088                         case CVAR:      /* '$' */
1089                                 PARSESUB();             /* parse substitution */
1090                                 break;
1091                         case CENDVAR:   /* CLOSEBRACE */
1092                                 if (varnest > 0 && !ISDBLQUOTE()) {
1093                                         varnest--;
1094                                         USTPUTC(CTLENDVAR, out);
1095                                 } else {
1096                                         USTPUTC(c, out);
1097                                 }
1098                                 break;
1099                         case CLP:       /* '(' in arithmetic */
1100                                 parenlevel++;
1101                                 USTPUTC(c, out);
1102                                 break;
1103                         case CRP:       /* ')' in arithmetic */
1104                                 if (parenlevel > 0) {
1105                                         USTPUTC(c, out);
1106                                         --parenlevel;
1107                                 } else {
1108                                         if (pgetc() == ')') {
1109                                                 if (--arinest == 0) {
1110                                                         USTPUTC(CTLENDARI, out);
1111                                                         syntax = prevsyntax;
1112                                                         if (syntax == DQSYNTAX)
1113                                                                 SETDBLQUOTE();
1114                                                         else
1115                                                                 CLRDBLQUOTE();
1116                                                 } else
1117                                                         USTPUTC(')', out);
1118                                         } else {
1119                                                 /*
1120                                                  * unbalanced parens
1121                                                  *  (don't 2nd guess - no error)
1122                                                  */
1123                                                 pungetc();
1124                                                 USTPUTC(')', out);
1125                                         }
1126                                 }
1127                                 break;
1128                         case CBQUOTE:   /* '`' */
1129                                 PARSEBACKQOLD();
1130                                 break;
1131                         case CEOF:
1132                                 goto endword;           /* exit outer loop */
1133                         default:
1134                                 if (varnest == 0 && !ISDBLQUOTE())
1135                                         goto endword;   /* exit outer loop */
1136                                 USTPUTC(c, out);
1137                         }
1138                         c = pgetc_macro();
1139                 }
1140         }
1141 endword:
1142         if (syntax == ARISYNTAX)
1143                 synerror("Missing '))'");
1144         if (syntax != BASESYNTAX && /* ! parsebackquote && */ eofmark == NULL)
1145                 synerror("Unterminated quoted string");
1146         if (varnest != 0) {
1147                 startlinno = plinno;
1148                 /* { */
1149                 synerror("Missing '}'");
1150         }
1151         USTPUTC('\0', out);
1152         len = out - stackblock();
1153         out = stackblock();
1154         if (eofmark == NULL) {
1155                 if ((c == '>' || c == '<')
1156                  && quotef == 0
1157                  && (*out == '\0' || is_number(out))) {
1158                         PARSEREDIR();
1159                         return lasttoken = TREDIR;
1160                 } else {
1161                         pungetc();
1162                 }
1163         }
1164         quoteflag = quotef;
1165         backquotelist = bqlist;
1166         grabstackblock(len);
1167         wordtext = out;
1168         if (dblquotep != NULL)
1169             ckfree(dblquotep);
1170         return lasttoken = TWORD;
1171 /* end of readtoken routine */
1172
1173
1174
1175 /*
1176  * Check to see whether we are at the end of the here document.  When this
1177  * is called, c is set to the first character of the next input line.  If
1178  * we are at the end of the here document, this routine sets the c to PEOF.
1179  */
1180
1181 checkend: {
1182         if (eofmark) {
1183                 if (striptabs) {
1184                         while (c == '\t')
1185                                 c = pgetc();
1186                 }
1187                 if (c == *eofmark) {
1188                         if (pfgets(line, sizeof line) != NULL) {
1189                                 char *p, *q;
1190
1191                                 p = line;
1192                                 for (q = eofmark + 1 ; *q && *p == *q ; p++, q++)
1193                                         continue;
1194                                 if ((*p == '\0' || *p == '\n') && *q == '\0') {
1195                                         c = PEOF;
1196                                         plinno++;
1197                                         needprompt = doprompt;
1198                                 } else {
1199                                         pushstring(line, strlen(line), NULL);
1200                                 }
1201                         }
1202                 }
1203         }
1204         goto checkend_return;
1205 }
1206
1207
1208 /*
1209  * Parse a redirection operator.  The variable "out" points to a string
1210  * specifying the fd to be redirected.  The variable "c" contains the
1211  * first character of the redirection operator.
1212  */
1213
1214 parseredir: {
1215         char fd[64];
1216         union node *np;
1217         strlcpy(fd, out, sizeof(fd));
1218
1219         np = (union node *)stalloc(sizeof (struct nfile));
1220         if (c == '>') {
1221                 np->nfile.fd = 1;
1222                 c = pgetc();
1223                 if (c == '>')
1224                         np->type = NAPPEND;
1225                 else if (c == '|')
1226                         np->type = NCLOBBER;
1227                 else if (c == '&')
1228                         np->type = NTOFD;
1229                 else {
1230                         np->type = NTO;
1231                         pungetc();
1232                 }
1233         } else {        /* c == '<' */
1234                 np->nfile.fd = 0;
1235                 switch (c = pgetc()) {
1236                 case '<':
1237                         if (sizeof (struct nfile) != sizeof (struct nhere)) {
1238                                 np = (union node *)stalloc(sizeof (struct nhere));
1239                                 np->nfile.fd = 0;
1240                         }
1241                         np->type = NHERE;
1242                         heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
1243                         heredoc->here = np;
1244                         if ((c = pgetc()) == '-') {
1245                                 heredoc->striptabs = 1;
1246                         } else {
1247                                 heredoc->striptabs = 0;
1248                                 pungetc();
1249                         }
1250                         break;
1251
1252                 case '&':
1253                         np->type = NFROMFD;
1254                         break;
1255
1256                 case '>':
1257                         np->type = NFROMTO;
1258                         break;
1259
1260                 default:
1261                         np->type = NFROM;
1262                         pungetc();
1263                         break;
1264                 }
1265         }
1266         if (*fd != '\0')
1267                 np->nfile.fd = number(fd);
1268         redirnode = np;
1269         goto parseredir_return;
1270 }
1271
1272
1273 /*
1274  * Parse a substitution.  At this point, we have read the dollar sign
1275  * and nothing else.
1276  */
1277
1278 parsesub: {
1279         char buf[10];
1280         int subtype;
1281         int typeloc;
1282         int flags;
1283         char *p;
1284         static const char types[] = "}-+?=";
1285         int i;
1286         int linno;
1287
1288         c = pgetc();
1289         if (c != '(' && c != OPENBRACE && !is_name(c) && !is_special(c)) {
1290                 USTPUTC('$', out);
1291                 pungetc();
1292         } else if (c == '(') {  /* $(command) or $((arith)) */
1293                 if (pgetc() == '(') {
1294                         PARSEARITH();
1295                 } else {
1296                         pungetc();
1297                         PARSEBACKQNEW();
1298                 }
1299         } else {
1300                 USTPUTC(CTLVAR, out);
1301                 typeloc = out - stackblock();
1302                 USTPUTC(VSNORMAL, out);
1303                 subtype = VSNORMAL;
1304                 flags = 0;
1305                 if (c == OPENBRACE) {
1306                         c = pgetc();
1307                         if (c == '#') {
1308                                 if ((c = pgetc()) == CLOSEBRACE)
1309                                         c = '#';
1310                                 else
1311                                         subtype = VSLENGTH;
1312                         }
1313                         else
1314                                 subtype = 0;
1315                 }
1316                 if (is_name(c)) {
1317                         p = out;
1318                         do {
1319                                 STPUTC(c, out);
1320                                 c = pgetc();
1321                         } while (is_in_name(c));
1322                         if (out - p == 6 && strncmp(p, "LINENO", 6) == 0) {
1323                                 /* Replace the variable name with the
1324                                  * current line number. */
1325                                 linno = plinno;
1326                                 if (funclinno != 0)
1327                                         linno -= funclinno - 1;
1328                                 snprintf(buf, sizeof(buf), "%d", linno);
1329                                 STADJUST(-6, out);
1330                                 for (i = 0; buf[i] != '\0'; i++)
1331                                         STPUTC(buf[i], out);
1332                                 flags |= VSLINENO;
1333                         }
1334                 } else if (is_digit(c)) {
1335                         do {
1336                                 USTPUTC(c, out);
1337                                 c = pgetc();
1338                         } while (is_digit(c));
1339                 }
1340                 else if (is_special(c)) {
1341                         USTPUTC(c, out);
1342                         c = pgetc();
1343                 }
1344                 else
1345 badsub:                 synerror("Bad substitution");
1346
1347                 STPUTC('=', out);
1348                 if (subtype == 0) {
1349                         switch (c) {
1350                         case ':':
1351                                 flags |= VSNUL;
1352                                 c = pgetc();
1353                                 /*FALLTHROUGH*/
1354                         default:
1355                                 p = strchr(types, c);
1356                                 if (p == NULL)
1357                                         goto badsub;
1358                                 subtype = p - types + VSNORMAL;
1359                                 break;
1360                         case '%':
1361                         case '#':
1362                                 {
1363                                         int cc = c;
1364                                         subtype = c == '#' ? VSTRIMLEFT :
1365                                                              VSTRIMRIGHT;
1366                                         c = pgetc();
1367                                         if (c == cc)
1368                                                 subtype++;
1369                                         else
1370                                                 pungetc();
1371                                         break;
1372                                 }
1373                         }
1374                 } else {
1375                         pungetc();
1376                 }
1377                 if (ISDBLQUOTE() || arinest)
1378                         flags |= VSQUOTE;
1379                 *(stackblock() + typeloc) = subtype | flags;
1380                 if (subtype != VSNORMAL) {
1381                         varnest++;
1382                         if (varnest >= maxnest) {
1383                                 dblquotep = ckrealloc(dblquotep, maxnest / 8);
1384                                 dblquotep[(maxnest / 32) - 1] = 0;
1385                                 maxnest += 32;
1386                         }
1387                 }
1388         }
1389         goto parsesub_return;
1390 }
1391
1392
1393 /*
1394  * Called to parse command substitutions.  Newstyle is set if the command
1395  * is enclosed inside $(...); nlpp is a pointer to the head of the linked
1396  * list of commands (passed by reference), and savelen is the number of
1397  * characters on the top of the stack which must be preserved.
1398  */
1399
1400 parsebackq: {
1401         struct nodelist **nlpp;
1402         int savepbq;
1403         union node *n;
1404         char *volatile str = NULL;
1405         struct jmploc jmploc;
1406         struct jmploc *volatile savehandler = NULL;
1407         int savelen;
1408         int saveprompt;
1409
1410         savepbq = parsebackquote;
1411         if (setjmp(jmploc.loc)) {
1412                 if (str)
1413                         ckfree(str);
1414                 parsebackquote = 0;
1415                 handler = savehandler;
1416                 longjmp(handler->loc, 1);
1417         }
1418         INTOFF;
1419         str = NULL;
1420         savelen = out - stackblock();
1421         if (savelen > 0) {
1422                 str = ckmalloc(savelen);
1423                 memcpy(str, stackblock(), savelen);
1424         }
1425         savehandler = handler;
1426         handler = &jmploc;
1427         INTON;
1428         if (oldstyle) {
1429                 /* We must read until the closing backquote, giving special
1430                    treatment to some slashes, and then push the string and
1431                    reread it as input, interpreting it normally.  */
1432                 char *pout;
1433                 int pc;
1434                 int psavelen;
1435                 char *pstr;
1436
1437
1438                 STARTSTACKSTR(pout);
1439                 for (;;) {
1440                         if (needprompt) {
1441                                 setprompt(2);
1442                                 needprompt = 0;
1443                         }
1444                         switch (pc = pgetc()) {
1445                         case '`':
1446                                 goto done;
1447
1448                         case '\\':
1449                                 if ((pc = pgetc()) == '\n') {
1450                                         plinno++;
1451                                         if (doprompt)
1452                                                 setprompt(2);
1453                                         else
1454                                                 setprompt(0);
1455                                         /*
1456                                          * If eating a newline, avoid putting
1457                                          * the newline into the new character
1458                                          * stream (via the STPUTC after the
1459                                          * switch).
1460                                          */
1461                                         continue;
1462                                 }
1463                                 if (pc != '\\' && pc != '`' && pc != '$'
1464                                     && (!ISDBLQUOTE() || pc != '"'))
1465                                         STPUTC('\\', pout);
1466                                 break;
1467
1468                         case '\n':
1469                                 plinno++;
1470                                 needprompt = doprompt;
1471                                 break;
1472
1473                         case PEOF:
1474                                 startlinno = plinno;
1475                                 synerror("EOF in backquote substitution");
1476                                 break;
1477
1478                         default:
1479                                 break;
1480                         }
1481                         STPUTC(pc, pout);
1482                 }
1483 done:
1484                 STPUTC('\0', pout);
1485                 psavelen = pout - stackblock();
1486                 if (psavelen > 0) {
1487                         pstr = grabstackstr(pout);
1488                         setinputstring(pstr, 1);
1489                 }
1490         }
1491         nlpp = &bqlist;
1492         while (*nlpp)
1493                 nlpp = &(*nlpp)->next;
1494         *nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
1495         (*nlpp)->next = NULL;
1496         parsebackquote = oldstyle;
1497
1498         if (oldstyle) {
1499                 saveprompt = doprompt;
1500                 doprompt = 0;
1501         } else
1502                 saveprompt = 0;
1503
1504         n = list(0, oldstyle);
1505
1506         if (oldstyle)
1507                 doprompt = saveprompt;
1508         else {
1509                 if (readtoken() != TRP)
1510                         synexpect(TRP);
1511         }
1512
1513         (*nlpp)->n = n;
1514         if (oldstyle) {
1515                 /*
1516                  * Start reading from old file again, ignoring any pushed back
1517                  * tokens left from the backquote parsing
1518                  */
1519                 popfile();
1520                 tokpushback = 0;
1521         }
1522         while (stackblocksize() <= savelen)
1523                 growstackblock();
1524         STARTSTACKSTR(out);
1525         if (str) {
1526                 memcpy(out, str, savelen);
1527                 STADJUST(savelen, out);
1528                 INTOFF;
1529                 ckfree(str);
1530                 str = NULL;
1531                 INTON;
1532         }
1533         parsebackquote = savepbq;
1534         handler = savehandler;
1535         if (arinest || ISDBLQUOTE())
1536                 USTPUTC(CTLBACKQ | CTLQUOTE, out);
1537         else
1538                 USTPUTC(CTLBACKQ, out);
1539         if (oldstyle)
1540                 goto parsebackq_oldreturn;
1541         else
1542                 goto parsebackq_newreturn;
1543 }
1544
1545 /*
1546  * Parse an arithmetic expansion (indicate start of one and set state)
1547  */
1548 parsearith: {
1549
1550         if (++arinest == 1) {
1551                 prevsyntax = syntax;
1552                 syntax = ARISYNTAX;
1553                 USTPUTC(CTLARI, out);
1554                 if (ISDBLQUOTE())
1555                         USTPUTC('"',out);
1556                 else
1557                         USTPUTC(' ',out);
1558         } else {
1559                 /*
1560                  * we collapse embedded arithmetic expansion to
1561                  * parenthesis, which should be equivalent
1562                  */
1563                 USTPUTC('(', out);
1564         }
1565         goto parsearith_return;
1566 }
1567
1568 } /* end of readtoken */
1569
1570
1571
1572 #ifdef mkinit
1573 RESET {
1574         tokpushback = 0;
1575         checkkwd = 0;
1576 }
1577 #endif
1578
1579 /*
1580  * Returns true if the text contains nothing to expand (no dollar signs
1581  * or backquotes).
1582  */
1583
1584 STATIC int
1585 noexpand(char *text)
1586 {
1587         char *p;
1588         char c;
1589
1590         p = text;
1591         while ((c = *p++) != '\0') {
1592                 if (c == CTLQUOTEMARK)
1593                         continue;
1594                 if (c == CTLESC)
1595                         p++;
1596                 else if (BASESYNTAX[(int)c] == CCTL)
1597                         return 0;
1598         }
1599         return 1;
1600 }
1601
1602
1603 /*
1604  * Return true if the argument is a legal variable name (a letter or
1605  * underscore followed by zero or more letters, underscores, and digits).
1606  */
1607
1608 int
1609 goodname(char *name)
1610         {
1611         char *p;
1612
1613         p = name;
1614         if (! is_name(*p))
1615                 return 0;
1616         while (*++p) {
1617                 if (! is_in_name(*p))
1618                         return 0;
1619         }
1620         return 1;
1621 }
1622
1623
1624 /*
1625  * Called when an unexpected token is read during the parse.  The argument
1626  * is the token that is expected, or -1 if more than one type of token can
1627  * occur at this point.
1628  */
1629
1630 STATIC void
1631 synexpect(int token)
1632 {
1633         char msg[64];
1634
1635         if (token >= 0) {
1636                 fmtstr(msg, 64, "%s unexpected (expecting %s)",
1637                         tokname[lasttoken], tokname[token]);
1638         } else {
1639                 fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
1640         }
1641         synerror(msg);
1642         /* NOTREACHED */
1643 }
1644
1645
1646 STATIC void
1647 synerror(const char *msg)
1648 {
1649         if (commandname)
1650                 outfmt(&errout, "%s: %d: ", commandname, startlinno);
1651         else
1652                 outfmt(&errout, "%s: ", getprogname());
1653         outfmt(&errout, "Syntax error: %s\n", msg);
1654         error(NULL);
1655         /* NOTREACHED */
1656 }
1657
1658 STATIC void
1659 setprompt(int which)
1660 {
1661         whichprompt = which;
1662
1663 #ifndef SMALL
1664         if (!el)
1665 #endif
1666                 out2str(getprompt(NULL));
1667 }
1668
1669 /*
1670  * called by editline -- any expansions to the prompt
1671  *    should be added here.
1672  */
1673 const char *
1674 getprompt(void *unused)
1675         {
1676         switch (whichprompt) {
1677         case 0:
1678                 return "";
1679         case 1:
1680                 return ps1val();
1681         case 2:
1682                 return ps2val();
1683         default:
1684                 return "<internal prompt error>";
1685         }
1686 }