bin/sh/parser.c

   1 /*      $NetBSD: parser.c,v 1.73 2008/11/08 00:14:05 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 1.73 2008/11/08 00:14:05 christos Exp $");
  41 #endif
  42 #endif /* not lint */
  43
  44 #include <stdlib.h>
  45
  46 #include "shell.h"
  47 #include "parser.h"
  48 #include "nodes.h"
  49 #include "expand.h"     /* defines rmescapes() */
  50 #include "eval.h"       /* defines commandname */
  51 #include "redir.h"      /* defines copyfd() */
  52 #include "syntax.h"
  53 #include "options.h"
  54 #include "input.h"
  55 #include "output.h"
  56 #include "var.h"
  57 #include "error.h"
  58 #include "memalloc.h"
  59 #include "mystring.h"
  60 #include "alias.h"
  61 #include "show.h"
  62 #ifndef SMALL
  63 #include "myhistedit.h"
  64 #endif
  65
  66 /*
  67  * Shell command parser.
  68  */
  69
  70 #define EOFMARKLEN 79
  71
  72 /* values returned by readtoken */
  73 #include "token.h"
  74
  75 #define OPENBRACE '{'
  76 #define CLOSEBRACE '}'
  77
  78
  79 struct heredoc {
  80         struct heredoc *next;   /* next here document in list */
  81         union node *here;               /* redirection node */
  82         char *eofmark;          /* string indicating end of input */
  83         int striptabs;          /* if set, strip leading tabs */
  84 };
  85
  86
  87
  88 static int noalias = 0;         /* when set, don't handle aliases */
  89 struct heredoc *heredoclist;    /* list of here documents to read */
  90 int parsebackquote;             /* nonzero if we are inside backquotes */
  91 int doprompt;                   /* if set, prompt the user */
  92 int needprompt;                 /* true if interactive and at start of line */
  93 int lasttoken;                  /* last token read */
  94 MKINIT int tokpushback;         /* last token pushed back */
  95 char *wordtext;                 /* text of last word returned by readtoken */
  96 MKINIT int checkkwd;            /* 1 == check for kwds, 2 == also eat newlines */
  97 struct nodelist *backquotelist;
  98 union node *redirnode;
  99 struct heredoc *heredoc;
 100 int quoteflag;                  /* set if (part of) last token was quoted */
 101 int startlinno;                 /* line # where last token started */
 102
 103
 104 STATIC union node *list(int, int);
 105 STATIC union node *andor(void);
 106 STATIC union node *pipeline(void);
 107 STATIC union node *command(void);
 108 STATIC union node *simplecmd(union node **, union node *);
 109 STATIC union node *makename(void);
 110 STATIC void parsefname(void);
 111 STATIC void parseheredoc(void);
 112 STATIC int peektoken(void);
 113 STATIC int readtoken(void);
 114 STATIC int xxreadtoken(void);
 115 STATIC int readtoken1(int, char const *, char *, int);
 116 STATIC int noexpand(char *);
 117 STATIC void synexpect(int) __dead;
 118 STATIC void synerror(const char *) __dead;
 119 STATIC void setprompt(int);
 120
 121
 122 /*
 123  * Read and parse a command.  Returns NEOF on end of file.  (NULL is a
 124  * valid parse tree indicating a blank line.)
 125  */
 126
 127 union node *
 128 parsecmd(int interact)
 129 {
 130         int t;
 131
 132         tokpushback = 0;
 133         doprompt = interact;
 134         if (doprompt)
 135                 setprompt(1);
 136         else
 137                 setprompt(0);
 138         needprompt = 0;
 139         t = readtoken();
 140         if (t == TEOF)
 141                 return NEOF;
 142         if (t == TNL)
 143                 return NULL;
 144         tokpushback++;
 145         return list(1, 0);
 146 }
 147
 148
 149 STATIC union node *
 150 list(int nlflag, int erflag)
 151 {
 152         union node *n1, *n2, *n3;
 153         int tok;
 154         TRACE(("list: entered\n"));
 155
 156         checkkwd = 2;
 157         if (nlflag == 0 && tokendlist[peektoken()])
 158                 return NULL;
 159         n1 = NULL;
 160         for (;;) {
 161                 n2 = andor();
 162                 tok = readtoken();
 163                 if (tok == TBACKGND) {
 164                         if (n2->type == NCMD || n2->type == NPIPE) {
 165                                 n2->ncmd.backgnd = 1;
 166                         } else if (n2->type == NREDIR) {
 167                                 n2->type = NBACKGND;
 168                         } else {
 169                                 n3 = (union node *)stalloc(sizeof (struct nredir));
 170                                 n3->type = NBACKGND;
 171                                 n3->nredir.n = n2;
 172                                 n3->nredir.redirect = NULL;
 173                                 n2 = n3;
 174                         }
 175                 }
 176                 if (n1 == NULL) {
 177                         n1 = n2;
 178                 }
 179                 else {
 180                         n3 = (union node *)stalloc(sizeof (struct nbinary));
 181                         n3->type = NSEMI;
 182                         n3->nbinary.ch1 = n1;
 183                         n3->nbinary.ch2 = n2;
 184                         n1 = n3;
 185                 }
 186                 switch (tok) {
 187                 case TBACKGND:
 188                 case TSEMI:
 189                         tok = readtoken();
 190                         /* fall through */
 191                 case TNL:
 192                         if (tok == TNL) {
 193                                 parseheredoc();
 194                                 if (nlflag)
 195                                         return n1;
 196                         } else {
 197                                 tokpushback++;
 198                         }
 199                         checkkwd = 2;
 200                         if (tokendlist[peektoken()])
 201                                 return n1;
 202                         break;
 203                 case TEOF:
 204                         if (heredoclist)
 205                                 parseheredoc();
 206                         else
 207                                 pungetc();              /* push back EOF on input */
 208                         return n1;
 209                 default:
 210                         if (nlflag || erflag)
 211                                 synexpect(-1);
 212                         tokpushback++;
 213                         return n1;
 214                 }
 215         }
 216 }
 217
 218
 219
 220 STATIC union node *
 221 andor(void)
 222 {
 223         union node *n1, *n2, *n3;
 224         int t;
 225
 226         TRACE(("andor: entered\n"));
 227         n1 = pipeline();
 228         for (;;) {
 229                 if ((t = readtoken()) == TAND) {
 230                         t = NAND;
 231                 } else if (t == TOR) {
 232                         t = NOR;
 233                 } else {
 234                         tokpushback++;
 235                         return n1;
 236                 }
 237                 n2 = pipeline();
 238                 n3 = (union node *)stalloc(sizeof (struct nbinary));
 239                 n3->type = t;
 240                 n3->nbinary.ch1 = n1;
 241                 n3->nbinary.ch2 = n2;
 242                 n1 = n3;
 243         }
 244 }
 245
 246
 247
 248 STATIC union node *
 249 pipeline(void)
 250 {
 251         union node *n1, *n2, *pipenode;
 252         struct nodelist *lp, *prev;
 253         int negate;
 254
 255         TRACE(("pipeline: entered\n"));
 256
 257         negate = 0;
 258         checkkwd = 2;
 259         while (readtoken() == TNOT) {
 260                 TRACE(("pipeline: TNOT recognized\n"));
 261                 negate = !negate;
 262         }
 263         tokpushback++;
 264         n1 = command();
 265         if (readtoken() == TPIPE) {
 266                 pipenode = (union node *)stalloc(sizeof (struct npipe));
 267                 pipenode->type = NPIPE;
 268                 pipenode->npipe.backgnd = 0;
 269                 lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 270                 pipenode->npipe.cmdlist = lp;
 271                 lp->n = n1;
 272                 do {
 273                         prev = lp;
 274                         lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 275                         lp->n = command();
 276                         prev->next = lp;
 277                 } while (readtoken() == TPIPE);
 278                 lp->next = NULL;
 279                 n1 = pipenode;
 280         }
 281         tokpushback++;
 282         if (negate) {
 283                 TRACE(("negate pipeline\n"));
 284                 n2 = (union node *)stalloc(sizeof (struct nnot));
 285                 n2->type = NNOT;
 286                 n2->nnot.com = n1;
 287                 return n2;
 288         } else
 289                 return n1;
 290 }
 291
 292
 293
 294 STATIC union node *
 295 command(void)
 296 {
 297         union node *n1, *n2;
 298         union node *ap, **app;
 299         union node *cp, **cpp;
 300         union node *redir, **rpp;
 301         int t, negate = 0;
 302
 303         TRACE(("command: entered\n"));
 304
 305         checkkwd = 2;
 306         redir = NULL;
 307         n1 = NULL;
 308         rpp = &redir;
 309
 310         /* Check for redirection which may precede command */
 311         while (readtoken() == TREDIR) {
 312                 *rpp = n2 = redirnode;
 313                 rpp = &n2->nfile.next;
 314                 parsefname();
 315         }
 316         tokpushback++;
 317
 318         while (readtoken() == TNOT) {
 319                 TRACE(("command: TNOT recognized\n"));
 320                 negate = !negate;
 321         }
 322         tokpushback++;
 323
 324         switch (readtoken()) {
 325         case TIF:
 326                 n1 = (union node *)stalloc(sizeof (struct nif));
 327                 n1->type = NIF;
 328                 n1->nif.test = list(0, 0);
 329                 if (readtoken() != TTHEN)
 330                         synexpect(TTHEN);
 331                 n1->nif.ifpart = list(0, 0);
 332                 n2 = n1;
 333                 while (readtoken() == TELIF) {
 334                         n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
 335                         n2 = n2->nif.elsepart;
 336                         n2->type = NIF;
 337                         n2->nif.test = list(0, 0);
 338                         if (readtoken() != TTHEN)
 339                                 synexpect(TTHEN);
 340                         n2->nif.ifpart = list(0, 0);
 341                 }
 342                 if (lasttoken == TELSE)
 343                         n2->nif.elsepart = list(0, 0);
 344                 else {
 345                         n2->nif.elsepart = NULL;
 346                         tokpushback++;
 347                 }
 348                 if (readtoken() != TFI)
 349                         synexpect(TFI);
 350                 checkkwd = 1;
 351                 break;
 352         case TWHILE:
 353         case TUNTIL: {
 354                 int got;
 355                 n1 = (union node *)stalloc(sizeof (struct nbinary));
 356                 n1->type = (lasttoken == TWHILE)? NWHILE : NUNTIL;
 357                 n1->nbinary.ch1 = list(0, 0);
 358                 if ((got=readtoken()) != TDO) {
 359 TRACE(("expecting DO got %s %s\n", tokname[got], got == TWORD ? wordtext : ""));
 360                         synexpect(TDO);
 361                 }
 362                 n1->nbinary.ch2 = list(0, 0);
 363                 if (readtoken() != TDONE)
 364                         synexpect(TDONE);
 365                 checkkwd = 1;
 366                 break;
 367         }
 368         case TFOR:
 369                 if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
 370                         synerror("Bad for loop variable");
 371                 n1 = (union node *)stalloc(sizeof (struct nfor));
 372                 n1->type = NFOR;
 373                 n1->nfor.var = wordtext;
 374                 if (readtoken() == TWORD && ! quoteflag && equal(wordtext, "in")) {
 375                         app = &ap;
 376                         while (readtoken() == TWORD) {
 377                                 n2 = (union node *)stalloc(sizeof (struct narg));
 378                                 n2->type = NARG;
 379                                 n2->narg.text = wordtext;
 380                                 n2->narg.backquote = backquotelist;
 381                                 *app = n2;
 382                                 app = &n2->narg.next;
 383                         }
 384                         *app = NULL;
 385                         n1->nfor.args = ap;
 386                         if (lasttoken != TNL && lasttoken != TSEMI)
 387                                 synexpect(-1);
 388                 } else {
 389                         static char argvars[5] = {CTLVAR, VSNORMAL|VSQUOTE,
 390                                                                    '@', '=', '\0'};
 391                         n2 = (union node *)stalloc(sizeof (struct narg));
 392                         n2->type = NARG;
 393                         n2->narg.text = argvars;
 394                         n2->narg.backquote = NULL;
 395                         n2->narg.next = NULL;
 396                         n1->nfor.args = n2;
 397                         /*
 398                          * Newline or semicolon here is optional (but note
 399                          * that the original Bourne shell only allowed NL).
 400                          */
 401                         if (lasttoken != TNL && lasttoken != TSEMI)
 402                                 tokpushback++;
 403                 }
 404                 checkkwd = 2;
 405                 if ((t = readtoken()) == TDO)
 406                         t = TDONE;
 407                 else if (t == TBEGIN)
 408                         t = TEND;
 409                 else
 410                         synexpect(-1);
 411                 n1->nfor.body = list(0, 0);
 412                 if (readtoken() != t)
 413                         synexpect(t);
 414                 checkkwd = 1;
 415                 break;
 416         case TCASE:
 417                 n1 = (union node *)stalloc(sizeof (struct ncase));
 418                 n1->type = NCASE;
 419                 if (readtoken() != TWORD)
 420                         synexpect(TWORD);
 421                 n1->ncase.expr = n2 = (union node *)stalloc(sizeof (struct narg));
 422                 n2->type = NARG;
 423                 n2->narg.text = wordtext;
 424                 n2->narg.backquote = backquotelist;
 425                 n2->narg.next = NULL;
 426                 while (readtoken() == TNL);
 427                 if (lasttoken != TWORD || ! equal(wordtext, "in"))
 428                         synerror("expecting \"in\"");
 429                 cpp = &n1->ncase.cases;
 430                 noalias = 1;
 431                 checkkwd = 2, readtoken();
 432                 do {
 433                         *cpp = cp = (union node *)stalloc(sizeof (struct nclist));
 434                         if (lasttoken == TLP)
 435                                 readtoken();
 436                         cp->type = NCLIST;
 437                         app = &cp->nclist.pattern;
 438                         for (;;) {
 439                                 *app = ap = (union node *)stalloc(sizeof (struct narg));
 440                                 ap->type = NARG;
 441                                 ap->narg.text = wordtext;
 442                                 ap->narg.backquote = backquotelist;
 443                                 if (checkkwd = 2, readtoken() != TPIPE)
 444                                         break;
 445                                 app = &ap->narg.next;
 446                                 readtoken();
 447                         }
 448                         ap->narg.next = NULL;
 449                         noalias = 0;
 450                         if (lasttoken != TRP) {
 451                                 synexpect(TRP);
 452                         }
 453                         cp->nclist.body = list(0, 0);
 454
 455                         checkkwd = 2;
 456                         if ((t = readtoken()) != TESAC) {
 457                                 if (t != TENDCASE) {
 458                                         noalias = 0;
 459                                         synexpect(TENDCASE);
 460                                 } else {
 461                                         noalias = 1;
 462                                         checkkwd = 2;
 463                                         readtoken();
 464                                 }
 465                         }
 466                         cpp = &cp->nclist.next;
 467                 } while(lasttoken != TESAC);
 468                 noalias = 0;
 469                 *cpp = NULL;
 470                 checkkwd = 1;
 471                 break;
 472         case TLP:
 473                 n1 = (union node *)stalloc(sizeof (struct nredir));
 474                 n1->type = NSUBSHELL;
 475                 n1->nredir.n = list(0, 0);
 476                 n1->nredir.redirect = NULL;
 477                 if (readtoken() != TRP)
 478                         synexpect(TRP);
 479                 checkkwd = 1;
 480                 break;
 481         case TBEGIN:
 482                 n1 = list(0, 0);
 483                 if (readtoken() != TEND)
 484                         synexpect(TEND);
 485                 checkkwd = 1;
 486                 break;
 487         /* Handle an empty command like other simple commands.  */
 488         case TSEMI:
 489                 /*
 490                  * An empty command before a ; doesn't make much sense, and
 491                  * should certainly be disallowed in the case of `if ;'.
 492                  */
 493                 if (!redir)
 494                         synexpect(-1);
 495         case TAND:
 496         case TOR:
 497         case TNL:
 498         case TEOF:
 499         case TWORD:
 500         case TRP:
 501                 tokpushback++;
 502                 n1 = simplecmd(rpp, redir);
 503                 goto checkneg;
 504         default:
 505                 synexpect(-1);
 506                 /* NOTREACHED */
 507         }
 508
 509         /* Now check for redirection which may follow command */
 510         while (readtoken() == TREDIR) {
 511                 *rpp = n2 = redirnode;
 512                 rpp = &n2->nfile.next;
 513                 parsefname();
 514         }
 515         tokpushback++;
 516         *rpp = NULL;
 517         if (redir) {
 518                 if (n1->type != NSUBSHELL) {
 519                         n2 = (union node *)stalloc(sizeof (struct nredir));
 520                         n2->type = NREDIR;
 521                         n2->nredir.n = n1;
 522                         n1 = n2;
 523                 }
 524                 n1->nredir.redirect = redir;
 525         }
 526
 527 checkneg:
 528         if (negate) {
 529                 TRACE(("negate command\n"));
 530                 n2 = (union node *)stalloc(sizeof (struct nnot));
 531                 n2->type = NNOT;
 532                 n2->nnot.com = n1;
 533                 return n2;
 534         }
 535         else
 536                 return n1;
 537 }
 538
 539
 540 STATIC union node *
 541 simplecmd(union node **rpp, union node *redir)
 542 {
 543         union node *args, **app;
 544         union node **orig_rpp = rpp;
 545         union node *n = NULL, *n2;
 546         int negate = 0;
 547
 548         /* If we don't have any redirections already, then we must reset */
 549         /* rpp to be the address of the local redir variable.  */
 550         if (redir == 0)
 551                 rpp = &redir;
 552
 553         args = NULL;
 554         app = &args;
 555         /*
 556          * We save the incoming value, because we need this for shell
 557          * functions.  There can not be a redirect or an argument between
 558          * the function name and the open parenthesis.
 559          */
 560         orig_rpp = rpp;
 561
 562         while (readtoken() == TNOT) {
 563                 TRACE(("simplcmd: TNOT recognized\n"));
 564                 negate = !negate;
 565         }
 566         tokpushback++;
 567
 568         for (;;) {
 569                 if (readtoken() == TWORD) {
 570                         n = (union node *)stalloc(sizeof (struct narg));
 571                         n->type = NARG;
 572                         n->narg.text = wordtext;
 573                         n->narg.backquote = backquotelist;
 574                         *app = n;
 575                         app = &n->narg.next;
 576                 } else if (lasttoken == TREDIR) {
 577                         *rpp = n = redirnode;
 578                         rpp = &n->nfile.next;
 579                         parsefname();   /* read name of redirection file */
 580                 } else if (lasttoken == TLP && app == &args->narg.next
 581                                             && rpp == orig_rpp) {
 582                         /* We have a function */
 583                         if (readtoken() != TRP)
 584                                 synexpect(TRP);
 585                         rmescapes(n->narg.text);
 586                         if (!goodname(n->narg.text))
 587                                 synerror("Bad function name");
 588                         n->type = NDEFUN;
 589                         n->narg.next = command();
 590                         goto checkneg;
 591                 } else {
 592                         tokpushback++;
 593                         break;
 594                 }
 595         }
 596         *app = NULL;
 597         *rpp = NULL;
 598         n = (union node *)stalloc(sizeof (struct ncmd));
 599         n->type = NCMD;
 600         n->ncmd.backgnd = 0;
 601         n->ncmd.args = args;
 602         n->ncmd.redirect = redir;
 603
 604 checkneg:
 605         if (negate) {
 606                 TRACE(("negate simplecmd\n"));
 607                 n2 = (union node *)stalloc(sizeof (struct nnot));
 608                 n2->type = NNOT;
 609                 n2->nnot.com = n;
 610                 return n2;
 611         }
 612         else
 613                 return n;
 614 }
 615
 616 STATIC union node *
 617 makename(void)
 618 {
 619         union node *n;
 620
 621         n = (union node *)stalloc(sizeof (struct narg));
 622         n->type = NARG;
 623         n->narg.next = NULL;
 624         n->narg.text = wordtext;
 625         n->narg.backquote = backquotelist;
 626         return n;
 627 }
 628
 629 void fixredir(union node *n, const char *text, int err)
 630         {
 631         TRACE(("Fix redir %s %d\n", text, err));
 632         if (!err)
 633                 n->ndup.vname = NULL;
 634
 635         if (is_digit(text[0]) && text[1] == '\0')
 636                 n->ndup.dupfd = digit_val(text[0]);
 637         else if (text[0] == '-' && text[1] == '\0')
 638                 n->ndup.dupfd = -1;
 639         else {
 640
 641                 if (err)
 642                         synerror("Bad fd number");
 643                 else
 644                         n->ndup.vname = makename();
 645         }
 646 }
 647
 648
 649 STATIC void
 650 parsefname(void)
 651 {
 652         union node *n = redirnode;
 653
 654         if (readtoken() != TWORD)
 655                 synexpect(-1);
 656         if (n->type == NHERE) {
 657                 struct heredoc *here = heredoc;
 658                 struct heredoc *p;
 659                 int i;
 660
 661                 if (quoteflag == 0)
 662                         n->type = NXHERE;
 663                 TRACE(("Here document %d\n", n->type));
 664                 if (here->striptabs) {
 665                         while (*wordtext == '\t')
 666                                 wordtext++;
 667                 }
 668                 if (! noexpand(wordtext) || (i = strlen(wordtext)) == 0 || i > EOFMARKLEN)
 669                         synerror("Illegal eof marker for << redirection");
 670                 rmescapes(wordtext);
 671                 here->eofmark = wordtext;
 672                 here->next = NULL;
 673                 if (heredoclist == NULL)
 674                         heredoclist = here;
 675                 else {
 676                         for (p = heredoclist ; p->next ; p = p->next);
 677                         p->next = here;
 678                 }
 679         } else if (n->type == NTOFD || n->type == NFROMFD) {
 680                 fixredir(n, wordtext, 0);
 681         } else {
 682                 n->nfile.fname = makename();
 683         }
 684 }
 685
 686
 687 /*
 688  * Input any here documents.
 689  */
 690
 691 STATIC void
 692 parseheredoc(void)
 693 {
 694         struct heredoc *here;
 695         union node *n;
 696
 697         while (heredoclist) {
 698                 here = heredoclist;
 699                 heredoclist = here->next;
 700                 if (needprompt) {
 701                         setprompt(2);
 702                         needprompt = 0;
 703                 }
 704                 readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
 705                                 here->eofmark, here->striptabs);
 706                 n = (union node *)stalloc(sizeof (struct narg));
 707                 n->narg.type = NARG;
 708                 n->narg.next = NULL;
 709                 n->narg.text = wordtext;
 710                 n->narg.backquote = backquotelist;
 711                 here->here->nhere.doc = n;
 712         }
 713 }
 714
 715 STATIC int
 716 peektoken(void)
 717 {
 718         int t;
 719
 720         t = readtoken();
 721         tokpushback++;
 722         return (t);
 723 }
 724
 725 STATIC int
 726 readtoken(void)
 727 {
 728         int t;
 729         int savecheckkwd = checkkwd;
 730 #ifdef DEBUG
 731         int alreadyseen = tokpushback;
 732 #endif
 733         struct alias *ap;
 734
 735         top:
 736         t = xxreadtoken();
 737
 738         if (checkkwd) {
 739                 /*
 740                  * eat newlines
 741                  */
 742                 if (checkkwd == 2) {
 743                         checkkwd = 0;
 744                         while (t == TNL) {
 745                                 parseheredoc();
 746                                 t = xxreadtoken();
 747                         }
 748                 } else
 749                         checkkwd = 0;
 750                 /*
 751                  * check for keywords and aliases
 752                  */
 753                 if (t == TWORD && !quoteflag)
 754                 {
 755                         const char *const *pp;
 756
 757                         for (pp = parsekwd; *pp; pp++) {
 758                                 if (**pp == *wordtext && equal(*pp, wordtext))
 759                                 {
 760                                         lasttoken = t = pp -
 761                                             parsekwd + KWDOFFSET;
 762                                         TRACE(("keyword %s recognized\n", tokname[t]));
 763                                         goto out;
 764                                 }
 765                         }
 766                         if(!noalias &&
 767                             (ap = lookupalias(wordtext, 1)) != NULL) {
 768                                 pushstring(ap->val, strlen(ap->val), ap);
 769                                 checkkwd = savecheckkwd;
 770                                 goto top;
 771                         }
 772                 }
 773 out:
 774                 checkkwd = (t == TNOT) ? savecheckkwd : 0;
 775         }
 776         TRACE(("%stoken %s %s\n", alreadyseen ? "reread " : "", tokname[t], t == TWORD ? wordtext : ""));
 777         return (t);
 778 }
 779
 780
 781 /*
 782  * Read the next input token.
 783  * If the token is a word, we set backquotelist to the list of cmds in
 784  *      backquotes.  We set quoteflag to true if any part of the word was
 785  *      quoted.
 786  * If the token is TREDIR, then we set redirnode to a structure containing
 787  *      the redirection.
 788  * In all cases, the variable startlinno is set to the number of the line
 789  *      on which the token starts.
 790  *
 791  * [Change comment:  here documents and internal procedures]
 792  * [Readtoken shouldn't have any arguments.  Perhaps we should make the
 793  *  word parsing code into a separate routine.  In this case, readtoken
 794  *  doesn't need to have any internal procedures, but parseword does.
 795  *  We could also make parseoperator in essence the main routine, and
 796  *  have parseword (readtoken1?) handle both words and redirection.]
 797  */
 798
 799 #define RETURN(token)   return lasttoken = token
 800
 801 STATIC int
 802 xxreadtoken(void)
 803 {
 804         int c;
 805
 806         if (tokpushback) {
 807                 tokpushback = 0;
 808                 return lasttoken;
 809         }
 810         if (needprompt) {
 811                 setprompt(2);
 812                 needprompt = 0;
 813         }
 814         startlinno = plinno;
 815         for (;;) {      /* until token or start of word found */
 816                 c = pgetc_macro();
 817                 if (c == ' ' || c == '\t')
 818                         continue;               /* quick check for white space first */
 819                 switch (c) {
 820                 case ' ': case '\t':
 821                         continue;
 822                 case '#':
 823                         while ((c = pgetc()) != '\n' && c != PEOF);
 824                         pungetc();
 825                         continue;
 826                 case '\\':
 827                         if (pgetc() == '\n') {
 828                                 startlinno = ++plinno;
 829                                 if (doprompt)
 830                                         setprompt(2);
 831                                 else
 832                                         setprompt(0);
 833                                 continue;
 834                         }
 835                         pungetc();
 836                         goto breakloop;
 837                 case '\n':
 838                         plinno++;
 839                         needprompt = doprompt;
 840                         RETURN(TNL);
 841                 case PEOF:
 842                         RETURN(TEOF);
 843                 case '&':
 844                         if (pgetc() == '&')
 845                                 RETURN(TAND);
 846                         pungetc();
 847                         RETURN(TBACKGND);
 848                 case '|':
 849                         if (pgetc() == '|')
 850                                 RETURN(TOR);
 851                         pungetc();
 852                         RETURN(TPIPE);
 853                 case ';':
 854                         if (pgetc() == ';')
 855                                 RETURN(TENDCASE);
 856                         pungetc();
 857                         RETURN(TSEMI);
 858                 case '(':
 859                         RETURN(TLP);
 860                 case ')':
 861                         RETURN(TRP);
 862                 default:
 863                         goto breakloop;
 864                 }
 865         }
 866 breakloop:
 867         return readtoken1(c, BASESYNTAX, (char *)NULL, 0);
 868 #undef RETURN
 869 }
 870
 871
 872
 873 /*
 874  * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
 875  * is not NULL, read a here document.  In the latter case, eofmark is the
 876  * word which marks the end of the document and striptabs is true if
 877  * leading tabs should be stripped from the document.  The argument firstc
 878  * is the first character of the input token or document.
 879  *
 880  * Because C does not have internal subroutines, I have simulated them
 881  * using goto's to implement the subroutine linkage.  The following macros
 882  * will run code that appears at the end of readtoken1.
 883  */
 884
 885 #define CHECKEND()      {goto checkend; checkend_return:;}
 886 #define PARSEREDIR()    {goto parseredir; parseredir_return:;}
 887 #define PARSESUB()      {goto parsesub; parsesub_return:;}
 888 #define PARSEBACKQOLD() {oldstyle = 1; goto parsebackq; parsebackq_oldreturn:;}
 889 #define PARSEBACKQNEW() {oldstyle = 0; goto parsebackq; parsebackq_newreturn:;}
 890 #define PARSEARITH()    {goto parsearith; parsearith_return:;}
 891
 892 /*
 893  * Keep track of nested doublequotes in dblquote and doublequotep.
 894  * We use dblquote for the first 32 levels, and we expand to a malloc'ed
 895  * region for levels above that. Usually we never need to malloc.
 896  * This code assumes that an int is 32 bits. We don't use uint32_t,
 897  * because the rest of the code does not.
 898  */
 899 #define ISDBLQUOTE() ((varnest < 32) ? (dblquote & (1 << varnest)) : \
 900     (dblquotep[(varnest / 32) - 1] & (1 << (varnest % 32))))
 901
 902 #define SETDBLQUOTE() \
 903     if (varnest < 32) \
 904         dblquote |= (1 << varnest); \
 905     else \
 906         dblquotep[(varnest / 32) - 1] |= (1 << (varnest % 32))
 907
 908 #define CLRDBLQUOTE() \
 909     if (varnest < 32) \
 910         dblquote &= ~(1 << varnest); \
 911     else \
 912         dblquotep[(varnest / 32) - 1] &= ~(1 << (varnest % 32))
 913
 914 STATIC int
 915 readtoken1(int firstc, char const *syn, char *eofmark, int striptabs)
 916 {
 917         char const * volatile syntax = syn;
 918         int c = firstc;
 919         char * volatile out;
 920         int len;
 921         char line[EOFMARKLEN + 1];
 922         struct nodelist *bqlist;
 923         volatile int quotef;
 924         int * volatile dblquotep = NULL;
 925         volatile size_t maxnest = 32;
 926         volatile int dblquote;
 927         volatile size_t varnest;        /* levels of variables expansion */
 928         volatile int arinest;   /* levels of arithmetic expansion */
 929         volatile int parenlevel;        /* levels of parens in arithmetic */
 930         volatile int oldstyle;
 931         char const * volatile prevsyntax;       /* syntax before arithmetic */
 932 #ifdef __GNUC__
 933         prevsyntax = NULL;      /* XXX gcc4 */
 934 #endif
 935
 936         startlinno = plinno;
 937         dblquote = 0;
 938         varnest = 0;
 939         if (syntax == DQSYNTAX) {
 940                 SETDBLQUOTE();
 941         }
 942         quotef = 0;
 943         bqlist = NULL;
 944         arinest = 0;
 945         parenlevel = 0;
 946
 947         STARTSTACKSTR(out);
 948         loop: { /* for each line, until end of word */
 949 #if ATTY
 950                 if (c == '\034' && doprompt
 951                  && attyset() && ! equal(termval(), "emacs")) {
 952                         attyline();
 953                         if (syntax == BASESYNTAX)
 954                                 return readtoken();
 955                         c = pgetc();
 956                         goto loop;
 957                 }
 958 #endif
 959                 CHECKEND();     /* set c to PEOF if at end of here document */
 960                 for (;;) {      /* until end of line or end of word */
 961                         CHECKSTRSPACE(4, out);  /* permit 4 calls to USTPUTC */
 962                         switch(syntax[c]) {
 963                         case CNL:       /* '\n' */
 964                                 if (syntax == BASESYNTAX)
 965                                         goto endword;   /* exit outer loop */
 966                                 USTPUTC(c, out);
 967                                 plinno++;
 968                                 if (doprompt)
 969                                         setprompt(2);
 970                                 else
 971                                         setprompt(0);
 972                                 c = pgetc();
 973                                 goto loop;              /* continue outer loop */
 974                         case CWORD:
 975                                 USTPUTC(c, out);
 976                                 break;
 977                         case CCTL:
 978                                 if (eofmark == NULL || ISDBLQUOTE())
 979                                         USTPUTC(CTLESC, out);
 980                                 USTPUTC(c, out);
 981                                 break;
 982                         case CBACK:     /* backslash */
 983                                 c = pgetc();
 984                                 if (c == PEOF) {
 985                                         USTPUTC('\\', out);
 986                                         pungetc();
 987                                         break;
 988                                 }
 989                                 if (c == '\n') {
 990                                         if (doprompt)
 991                                                 setprompt(2);
 992                                         else
 993                                                 setprompt(0);
 994                                         break;
 995                                 }
 996                                 quotef = 1;
 997                                 if (ISDBLQUOTE() && c != '\\' &&
 998                                     c != '`' && c != '$' &&
 999                                     (c != '"' || eofmark != NULL))
1000                                         USTPUTC('\\', out);
1001                                 if (SQSYNTAX[c] == CCTL)
1002                                         USTPUTC(CTLESC, out);
1003                                 else if (eofmark == NULL) {
1004                                         USTPUTC(CTLQUOTEMARK, out);
1005                                         USTPUTC(c, out);
1006                                         if (varnest != 0)
1007                                                 USTPUTC(CTLQUOTEEND, out);
1008                                         break;
1009                                 }
1010                                 USTPUTC(c, out);
1011                                 break;
1012                         case CSQUOTE:
1013                                 if (syntax != SQSYNTAX) {
1014                                         if (eofmark == NULL)
1015                                                 USTPUTC(CTLQUOTEMARK, out);
1016                                         quotef = 1;
1017                                         syntax = SQSYNTAX;
1018                                         break;
1019                                 }
1020                                 if (eofmark != NULL && arinest == 0 &&
1021                                     varnest == 0) {
1022                                         /* Ignore inside quoted here document */
1023                                         USTPUTC(c, out);
1024                                         break;
1025                                 }
1026                                 /* End of single quotes... */
1027                                 if (arinest)
1028                                         syntax = ARISYNTAX;
1029                                 else {
1030                                         syntax = BASESYNTAX;
1031                                         if (varnest != 0)
1032                                                 USTPUTC(CTLQUOTEEND, out);
1033                                 }
1034                                 break;
1035                         case CDQUOTE:
1036                                 if (eofmark != NULL && arinest == 0 &&
1037                                     varnest == 0) {
1038                                         /* Ignore inside here document */
1039                                         USTPUTC(c, out);
1040                                         break;
1041                                 }
1042                                 quotef = 1;
1043                                 if (arinest) {
1044                                         if (ISDBLQUOTE()) {
1045                                                 syntax = ARISYNTAX;
1046                                                 CLRDBLQUOTE();
1047                                         } else {
1048                                                 syntax = DQSYNTAX;
1049                                                 SETDBLQUOTE();
1050                                                 USTPUTC(CTLQUOTEMARK, out);
1051                                         }
1052                                         break;
1053                                 }
1054                                 if (eofmark != NULL)
1055                                         break;
1056                                 if (ISDBLQUOTE()) {
1057                                         if (varnest != 0)
1058                                                 USTPUTC(CTLQUOTEEND, out);
1059                                         syntax = BASESYNTAX;
1060                                         CLRDBLQUOTE();
1061                                 } else {
1062                                         syntax = DQSYNTAX;
1063                                         SETDBLQUOTE();
1064                                         USTPUTC(CTLQUOTEMARK, out);
1065                                 }
1066                                 break;
1067                         case CVAR:      /* '$' */
1068                                 PARSESUB();             /* parse substitution */
1069                                 break;
1070                         case CENDVAR:   /* CLOSEBRACE */
1071                                 if (varnest > 0 && !ISDBLQUOTE()) {
1072                                         varnest--;
1073                                         USTPUTC(CTLENDVAR, out);
1074                                 } else {
1075                                         USTPUTC(c, out);
1076                                 }
1077                                 break;
1078                         case CLP:       /* '(' in arithmetic */
1079                                 parenlevel++;
1080                                 USTPUTC(c, out);
1081                                 break;
1082                         case CRP:       /* ')' in arithmetic */
1083                                 if (parenlevel > 0) {
1084                                         USTPUTC(c, out);
1085                                         --parenlevel;
1086                                 } else {
1087                                         if (pgetc() == ')') {
1088                                                 if (--arinest == 0) {
1089                                                         USTPUTC(CTLENDARI, out);
1090                                                         syntax = prevsyntax;
1091                                                         if (syntax == DQSYNTAX)
1092                                                                 SETDBLQUOTE();
1093                                                         else
1094                                                                 CLRDBLQUOTE();
1095                                                 } else
1096                                                         USTPUTC(')', out);
1097                                         } else {
1098                                                 /*
1099                                                  * unbalanced parens
1100                                                  *  (don't 2nd guess - no error)
1101                                                  */
1102                                                 pungetc();
1103                                                 USTPUTC(')', out);
1104                                         }
1105                                 }
1106                                 break;
1107                         case CBQUOTE:   /* '`' */
1108                                 PARSEBACKQOLD();
1109                                 break;
1110                         case CEOF:
1111                                 goto endword;           /* exit outer loop */
1112                         default:
1113                                 if (varnest == 0)
1114                                         goto endword;   /* exit outer loop */
1115                                 USTPUTC(c, out);
1116                         }
1117                         c = pgetc_macro();
1118                 }
1119         }
1120 endword:
1121         if (syntax == ARISYNTAX)
1122                 synerror("Missing '))'");
1123         if (syntax != BASESYNTAX && /* ! parsebackquote && */ eofmark == NULL)
1124                 synerror("Unterminated quoted string");
1125         if (varnest != 0) {
1126                 startlinno = plinno;
1127                 /* { */
1128                 synerror("Missing '}'");
1129         }
1130         USTPUTC('\0', out);
1131         len = out - stackblock();
1132         out = stackblock();
1133         if (eofmark == NULL) {
1134                 if ((c == '>' || c == '<')
1135                  && quotef == 0
1136                  && len <= 2
1137                  && (*out == '\0' || is_digit(*out))) {
1138                         PARSEREDIR();
1139                         return lasttoken = TREDIR;
1140                 } else {
1141                         pungetc();
1142                 }
1143         }
1144         quoteflag = quotef;
1145         backquotelist = bqlist;
1146         grabstackblock(len);
1147         wordtext = out;
1148         if (dblquotep != NULL)
1149             ckfree(dblquotep);
1150         return lasttoken = TWORD;
1151 /* end of readtoken routine */
1152
1153
1154
1155 /*
1156  * Check to see whether we are at the end of the here document.  When this
1157  * is called, c is set to the first character of the next input line.  If
1158  * we are at the end of the here document, this routine sets the c to PEOF.
1159  */
1160
1161 checkend: {
1162         if (eofmark) {
1163                 if (striptabs) {
1164                         while (c == '\t')
1165                                 c = pgetc();
1166                 }
1167                 if (c == *eofmark) {
1168                         if (pfgets(line, sizeof line) != NULL) {
1169                                 char *p, *q;
1170
1171                                 p = line;
1172                                 for (q = eofmark + 1 ; *q && *p == *q ; p++, q++);
1173                                 if ((*p == '\0' || *p == '\n') && *q == '\0') {
1174                                         c = PEOF;
1175                                         plinno++;
1176                                         needprompt = doprompt;
1177                                 } else {
1178                                         pushstring(line, strlen(line), NULL);
1179                                 }
1180                         }
1181                 }
1182         }
1183         goto checkend_return;
1184 }
1185
1186
1187 /*
1188  * Parse a redirection operator.  The variable "out" points to a string
1189  * specifying the fd to be redirected.  The variable "c" contains the
1190  * first character of the redirection operator.
1191  */
1192
1193 parseredir: {
1194         char fd = *out;
1195         union node *np;
1196
1197         np = (union node *)stalloc(sizeof (struct nfile));
1198         if (c == '>') {
1199                 np->nfile.fd = 1;
1200                 c = pgetc();
1201                 if (c == '>')
1202                         np->type = NAPPEND;
1203                 else if (c == '|')
1204                         np->type = NCLOBBER;
1205                 else if (c == '&')
1206                         np->type = NTOFD;
1207                 else {
1208                         np->type = NTO;
1209                         pungetc();
1210                 }
1211         } else {        /* c == '<' */
1212                 np->nfile.fd = 0;
1213                 switch (c = pgetc()) {
1214                 case '<':
1215                         if (sizeof (struct nfile) != sizeof (struct nhere)) {
1216                                 np = (union node *)stalloc(sizeof (struct nhere));
1217                                 np->nfile.fd = 0;
1218                         }
1219                         np->type = NHERE;
1220                         heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
1221                         heredoc->here = np;
1222                         if ((c = pgetc()) == '-') {
1223                                 heredoc->striptabs = 1;
1224                         } else {
1225                                 heredoc->striptabs = 0;
1226                                 pungetc();
1227                         }
1228                         break;
1229
1230                 case '&':
1231                         np->type = NFROMFD;
1232                         break;
1233
1234                 case '>':
1235                         np->type = NFROMTO;
1236                         break;
1237
1238                 default:
1239                         np->type = NFROM;
1240                         pungetc();
1241                         break;
1242                 }
1243         }
1244         if (fd != '\0')
1245                 np->nfile.fd = digit_val(fd);
1246         redirnode = np;
1247         goto parseredir_return;
1248 }
1249
1250
1251 /*
1252  * Parse a substitution.  At this point, we have read the dollar sign
1253  * and nothing else.
1254  */
1255
1256 parsesub: {
1257         int subtype;
1258         int typeloc;
1259         int flags;
1260         char *p;
1261         static const char types[] = "}-+?=";
1262
1263         c = pgetc();
1264         if (c != '(' && c != OPENBRACE && !is_name(c) && !is_special(c)) {
1265                 USTPUTC('$', out);
1266                 pungetc();
1267         } else if (c == '(') {  /* $(command) or $((arith)) */
1268                 if (pgetc() == '(') {
1269                         PARSEARITH();
1270                 } else {
1271                         pungetc();
1272                         PARSEBACKQNEW();
1273                 }
1274         } else {
1275                 USTPUTC(CTLVAR, out);
1276                 typeloc = out - stackblock();
1277                 USTPUTC(VSNORMAL, out);
1278                 subtype = VSNORMAL;
1279                 if (c == OPENBRACE) {
1280                         c = pgetc();
1281                         if (c == '#') {
1282                                 if ((c = pgetc()) == CLOSEBRACE)
1283                                         c = '#';
1284                                 else
1285                                         subtype = VSLENGTH;
1286                         }
1287                         else
1288                                 subtype = 0;
1289                 }
1290                 if (is_name(c)) {
1291                         do {
1292                                 STPUTC(c, out);
1293                                 c = pgetc();
1294                         } while (is_in_name(c));
1295                 } else if (is_digit(c)) {
1296                         do {
1297                                 USTPUTC(c, out);
1298                                 c = pgetc();
1299                         } while (is_digit(c));
1300                 }
1301                 else if (is_special(c)) {
1302                         USTPUTC(c, out);
1303                         c = pgetc();
1304                 }
1305                 else
1306 badsub:                 synerror("Bad substitution");
1307
1308                 STPUTC('=', out);
1309                 flags = 0;
1310                 if (subtype == 0) {
1311                         switch (c) {
1312                         case ':':
1313                                 flags = VSNUL;
1314                                 c = pgetc();
1315                                 /*FALLTHROUGH*/
1316                         default:
1317                                 p = strchr(types, c);
1318                                 if (p == NULL)
1319                                         goto badsub;
1320                                 subtype = p - types + VSNORMAL;
1321                                 break;
1322                         case '%':
1323                         case '#':
1324                                 {
1325                                         int cc = c;
1326                                         subtype = c == '#' ? VSTRIMLEFT :
1327                                                              VSTRIMRIGHT;
1328                                         c = pgetc();
1329                                         if (c == cc)
1330                                                 subtype++;
1331                                         else
1332                                                 pungetc();
1333                                         break;
1334                                 }
1335                         }
1336                 } else {
1337                         pungetc();
1338                 }
1339                 if (ISDBLQUOTE() || arinest)
1340                         flags |= VSQUOTE;
1341                 *(stackblock() + typeloc) = subtype | flags;
1342                 if (subtype != VSNORMAL) {
1343                         varnest++;
1344                         if (varnest >= maxnest) {
1345                                 dblquotep = ckrealloc(dblquotep, maxnest / 8);
1346                                 dblquotep[(maxnest / 32) - 1] = 0;
1347                                 maxnest += 32;
1348                         }
1349                 }
1350         }
1351         goto parsesub_return;
1352 }
1353
1354
1355 /*
1356  * Called to parse command substitutions.  Newstyle is set if the command
1357  * is enclosed inside $(...); nlpp is a pointer to the head of the linked
1358  * list of commands (passed by reference), and savelen is the number of
1359  * characters on the top of the stack which must be preserved.
1360  */
1361
1362 parsebackq: {
1363         struct nodelist **nlpp;
1364         int savepbq;
1365         union node *n;
1366         char *volatile str;
1367         struct jmploc jmploc;
1368         struct jmploc *volatile savehandler;
1369         int savelen;
1370         int saveprompt;
1371
1372         savepbq = parsebackquote;
1373         if (setjmp(jmploc.loc)) {
1374                 if (str)
1375                         ckfree(str);
1376                 parsebackquote = 0;
1377                 handler = savehandler;
1378                 longjmp(handler->loc, 1);
1379         }
1380         INTOFF;
1381         str = NULL;
1382         savelen = out - stackblock();
1383         if (savelen > 0) {
1384                 str = ckmalloc(savelen);
1385                 memcpy(str, stackblock(), savelen);
1386         }
1387         savehandler = handler;
1388         handler = &jmploc;
1389         INTON;
1390         if (oldstyle) {
1391                 /* We must read until the closing backquote, giving special
1392                    treatment to some slashes, and then push the string and
1393                    reread it as input, interpreting it normally.  */
1394                 char *pout;
1395                 int pc;
1396                 int psavelen;
1397                 char *pstr;
1398
1399
1400                 STARTSTACKSTR(pout);
1401                 for (;;) {
1402                         if (needprompt) {
1403                                 setprompt(2);
1404                                 needprompt = 0;
1405                         }
1406                         switch (pc = pgetc()) {
1407                         case '`':
1408                                 goto done;
1409
1410                         case '\\':
1411                                 if ((pc = pgetc()) == '\n') {
1412                                         plinno++;
1413                                         if (doprompt)
1414                                                 setprompt(2);
1415                                         else
1416                                                 setprompt(0);
1417                                         /*
1418                                          * If eating a newline, avoid putting
1419                                          * the newline into the new character
1420                                          * stream (via the STPUTC after the
1421                                          * switch).
1422                                          */
1423                                         continue;
1424                                 }
1425                                 if (pc != '\\' && pc != '`' && pc != '$'
1426                                     && (!ISDBLQUOTE() || pc != '"'))
1427                                         STPUTC('\\', pout);
1428                                 break;
1429
1430                         case '\n':
1431                                 plinno++;
1432                                 needprompt = doprompt;
1433                                 break;
1434
1435                         case PEOF:
1436                                 startlinno = plinno;
1437                                 synerror("EOF in backquote substitution");
1438                                 break;
1439
1440                         default:
1441                                 break;
1442                         }
1443                         STPUTC(pc, pout);
1444                 }
1445 done:
1446                 STPUTC('\0', pout);
1447                 psavelen = pout - stackblock();
1448                 if (psavelen > 0) {
1449                         pstr = grabstackstr(pout);
1450                         setinputstring(pstr, 1);
1451                 }
1452         }
1453         nlpp = &bqlist;
1454         while (*nlpp)
1455                 nlpp = &(*nlpp)->next;
1456         *nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
1457         (*nlpp)->next = NULL;
1458         parsebackquote = oldstyle;
1459
1460         if (oldstyle) {
1461                 saveprompt = doprompt;
1462                 doprompt = 0;
1463         } else
1464                 saveprompt = 0;
1465
1466         n = list(0, oldstyle);
1467
1468         if (oldstyle)
1469                 doprompt = saveprompt;
1470         else {
1471                 if (readtoken() != TRP)
1472                         synexpect(TRP);
1473         }
1474
1475         (*nlpp)->n = n;
1476         if (oldstyle) {
1477                 /*
1478                  * Start reading from old file again, ignoring any pushed back
1479                  * tokens left from the backquote parsing
1480                  */
1481                 popfile();
1482                 tokpushback = 0;
1483         }
1484         while (stackblocksize() <= savelen)
1485                 growstackblock();
1486         STARTSTACKSTR(out);
1487         if (str) {
1488                 memcpy(out, str, savelen);
1489                 STADJUST(savelen, out);
1490                 INTOFF;
1491                 ckfree(str);
1492                 str = NULL;
1493                 INTON;
1494         }
1495         parsebackquote = savepbq;
1496         handler = savehandler;
1497         if (arinest || ISDBLQUOTE())
1498                 USTPUTC(CTLBACKQ | CTLQUOTE, out);
1499         else
1500                 USTPUTC(CTLBACKQ, out);
1501         if (oldstyle)
1502                 goto parsebackq_oldreturn;
1503         else
1504                 goto parsebackq_newreturn;
1505 }
1506
1507 /*
1508  * Parse an arithmetic expansion (indicate start of one and set state)
1509  */
1510 parsearith: {
1511
1512         if (++arinest == 1) {
1513                 prevsyntax = syntax;
1514                 syntax = ARISYNTAX;
1515                 USTPUTC(CTLARI, out);
1516                 if (ISDBLQUOTE())
1517                         USTPUTC('"',out);
1518                 else
1519                         USTPUTC(' ',out);
1520         } else {
1521                 /*
1522                  * we collapse embedded arithmetic expansion to
1523                  * parenthesis, which should be equivalent
1524                  */
1525                 USTPUTC('(', out);
1526         }
1527         goto parsearith_return;
1528 }
1529
1530 } /* end of readtoken */
1531
1532
1533
1534 #ifdef mkinit
1535 RESET {
1536         tokpushback = 0;
1537         checkkwd = 0;
1538 }
1539 #endif
1540
1541 /*
1542  * Returns true if the text contains nothing to expand (no dollar signs
1543  * or backquotes).
1544  */
1545
1546 STATIC int
1547 noexpand(char *text)
1548 {
1549         char *p;
1550         char c;
1551
1552         p = text;
1553         while ((c = *p++) != '\0') {
1554                 if (c == CTLQUOTEMARK)
1555                         continue;
1556                 if (c == CTLESC)
1557                         p++;
1558                 else if (BASESYNTAX[(int)c] == CCTL)
1559                         return 0;
1560         }
1561         return 1;
1562 }
1563
1564
1565 /*
1566  * Return true if the argument is a legal variable name (a letter or
1567  * underscore followed by zero or more letters, underscores, and digits).
1568  */
1569
1570 int
1571 goodname(char *name)
1572         {
1573         char *p;
1574
1575         p = name;
1576         if (! is_name(*p))
1577                 return 0;
1578         while (*++p) {
1579                 if (! is_in_name(*p))
1580                         return 0;
1581         }
1582         return 1;
1583 }
1584
1585
1586 /*
1587  * Called when an unexpected token is read during the parse.  The argument
1588  * is the token that is expected, or -1 if more than one type of token can
1589  * occur at this point.
1590  */
1591
1592 STATIC void
1593 synexpect(int token)
1594 {
1595         char msg[64];
1596
1597         if (token >= 0) {
1598                 fmtstr(msg, 64, "%s unexpected (expecting %s)",
1599                         tokname[lasttoken], tokname[token]);
1600         } else {
1601                 fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
1602         }
1603         synerror(msg);
1604         /* NOTREACHED */
1605 }
1606
1607
1608 STATIC void
1609 synerror(const char *msg)
1610 {
1611         if (commandname)
1612                 outfmt(&errout, "%s: %d: ", commandname, startlinno);
1613         else
1614                 outfmt(&errout, "%s: ", getprogname());
1615         outfmt(&errout, "Syntax error: %s\n", msg);
1616         error((char *)NULL);
1617         /* NOTREACHED */
1618 }
1619
1620 STATIC void
1621 setprompt(int which)
1622 {
1623         whichprompt = which;
1624
1625 #ifndef SMALL
1626         if (!el)
1627 #endif
1628                 out2str(getprompt(NULL));
1629 }
1630
1631 /*
1632  * called by editline -- any expansions to the prompt
1633  *    should be added here.
1634  */
1635 const char *
1636 getprompt(void *unused)
1637         {
1638         switch (whichprompt) {
1639         case 0:
1640                 return "";
1641         case 1:
1642                 return ps1val();
1643         case 2:
1644                 return ps2val();
1645         default:
1646                 return "<internal prompt error>";
1647         }
1648 }