bin/sh/parser.c

   1 /*-
   2  * Copyright (c) 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Kenneth Almquist.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * @(#)parser.c 8.7 (Berkeley) 5/16/95
  37  * $FreeBSD: src/bin/sh/parser.c,v 1.58 2006/11/05 18:36:05 stefanf Exp $
  38  * $DragonFly: src/bin/sh/parser.c,v 1.10 2007/01/14 05:39:22 pavalos Exp $
  39  */
  40
  41 #include <stdlib.h>
  42 #include <unistd.h>
  43
  44 #include "shell.h"
  45 #include "parser.h"
  46 #include "nodes.h"
  47 #include "expand.h"     /* defines rmescapes() */
  48 #include "syntax.h"
  49 #include "options.h"
  50 #include "input.h"
  51 #include "output.h"
  52 #include "var.h"
  53 #include "error.h"
  54 #include "memalloc.h"
  55 #include "mystring.h"
  56 #include "alias.h"
  57 #include "show.h"
  58 #include "eval.h"
  59 #ifndef NO_HISTORY
  60 #include "myhistedit.h"
  61 #endif
  62
  63 /*
  64  * Shell command parser.
  65  */
  66
  67 #define EOFMARKLEN      79
  68 #define PROMPTLEN       128
  69
  70 /* values returned by readtoken */
  71 #include "token.h"
  72
  73
  74
  75 struct heredoc {
  76         struct heredoc *next;   /* next here document in list */
  77         union node *here;               /* redirection node */
  78         char *eofmark;          /* string indicating end of input */
  79         int striptabs;          /* if set, strip leading tabs */
  80 };
  81
  82
  83
  84 STATIC struct heredoc *heredoclist;     /* list of here documents to read */
  85 STATIC int parsebackquote;      /* nonzero if we are inside backquotes */
  86 STATIC int doprompt;            /* if set, prompt the user */
  87 STATIC int needprompt;          /* true if interactive and at start of line */
  88 STATIC int lasttoken;           /* last token read */
  89 MKINIT int tokpushback;         /* last token pushed back */
  90 STATIC char *wordtext;          /* text of last word returned by readtoken */
  91 MKINIT int checkkwd;            /* 1 == check for kwds, 2 == also eat newlines */
  92 STATIC struct nodelist *backquotelist;
  93 STATIC union node *redirnode;
  94 STATIC struct heredoc *heredoc;
  95 STATIC int quoteflag;           /* set if (part of) last token was quoted */
  96 STATIC int startlinno;          /* line # where last token started */
  97
  98 /* XXX When 'noaliases' is set to one, no alias expansion takes place. */
  99 static int noaliases = 0;
 100
 101
 102 STATIC union node *list(int);
 103 STATIC union node *andor(void);
 104 STATIC union node *pipeline(void);
 105 STATIC union node *command(void);
 106 STATIC union node *simplecmd(union node **, union node *);
 107 STATIC union node *makename(void);
 108 STATIC void parsefname(void);
 109 STATIC void parseheredoc(void);
 110 STATIC int peektoken(void);
 111 STATIC int readtoken(void);
 112 STATIC int xxreadtoken(void);
 113 STATIC int readtoken1(int, char const *, char *, int);
 114 STATIC int noexpand(char *);
 115 STATIC void synexpect(int);
 116 STATIC void synerror(const char *);
 117 STATIC void setprompt(int);
 118
 119
 120 /*
 121  * Read and parse a command.  Returns NEOF on end of file.  (NULL is a
 122  * valid parse tree indicating a blank line.)
 123  */
 124
 125 union node *
 126 parsecmd(int interact)
 127 {
 128         int t;
 129
 130         tokpushback = 0;
 131         doprompt = interact;
 132         if (doprompt)
 133                 setprompt(1);
 134         else
 135                 setprompt(0);
 136         needprompt = 0;
 137         t = readtoken();
 138         if (t == TEOF)
 139                 return NEOF;
 140         if (t == TNL)
 141                 return NULL;
 142         tokpushback++;
 143         return list(1);
 144 }
 145
 146
 147 STATIC union node *
 148 list(int nlflag)
 149 {
 150         union node *n1, *n2, *n3;
 151         int tok;
 152
 153         checkkwd = 2;
 154         if (nlflag == 0 && tokendlist[peektoken()])
 155                 return NULL;
 156         n1 = NULL;
 157         for (;;) {
 158                 n2 = andor();
 159                 tok = readtoken();
 160                 if (tok == TBACKGND) {
 161                         if (n2->type == NCMD || n2->type == NPIPE) {
 162                                 n2->ncmd.backgnd = 1;
 163                         } else if (n2->type == NREDIR) {
 164                                 n2->type = NBACKGND;
 165                         } else {
 166                                 n3 = (union node *)stalloc(sizeof (struct nredir));
 167                                 n3->type = NBACKGND;
 168                                 n3->nredir.n = n2;
 169                                 n3->nredir.redirect = NULL;
 170                                 n2 = n3;
 171                         }
 172                 }
 173                 if (n1 == NULL) {
 174                         n1 = n2;
 175                 }
 176                 else {
 177                         n3 = (union node *)stalloc(sizeof (struct nbinary));
 178                         n3->type = NSEMI;
 179                         n3->nbinary.ch1 = n1;
 180                         n3->nbinary.ch2 = n2;
 181                         n1 = n3;
 182                 }
 183                 switch (tok) {
 184                 case TBACKGND:
 185                 case TSEMI:
 186                         tok = readtoken();
 187                         /* FALLTHROUGH */
 188                 case TNL:
 189                         if (tok == TNL) {
 190                                 parseheredoc();
 191                                 if (nlflag)
 192                                         return n1;
 193                         } else {
 194                                 tokpushback++;
 195                         }
 196                         checkkwd = 2;
 197                         if (tokendlist[peektoken()])
 198                                 return n1;
 199                         break;
 200                 case TEOF:
 201                         if (heredoclist)
 202                                 parseheredoc();
 203                         else
 204                                 pungetc();              /* push back EOF on input */
 205                         return n1;
 206                 default:
 207                         if (nlflag)
 208                                 synexpect(-1);
 209                         tokpushback++;
 210                         return n1;
 211                 }
 212         }
 213 }
 214
 215
 216
 217 STATIC union node *
 218 andor(void)
 219 {
 220         union node *n1, *n2, *n3;
 221         int t;
 222
 223         n1 = pipeline();
 224         for (;;) {
 225                 if ((t = readtoken()) == TAND) {
 226                         t = NAND;
 227                 } else if (t == TOR) {
 228                         t = NOR;
 229                 } else {
 230                         tokpushback++;
 231                         return n1;
 232                 }
 233                 n2 = pipeline();
 234                 n3 = (union node *)stalloc(sizeof (struct nbinary));
 235                 n3->type = t;
 236                 n3->nbinary.ch1 = n1;
 237                 n3->nbinary.ch2 = n2;
 238                 n1 = n3;
 239         }
 240 }
 241
 242
 243
 244 STATIC union node *
 245 pipeline(void)
 246 {
 247         union node *n1, *n2, *pipenode;
 248         struct nodelist *lp, *prev;
 249         int negate;
 250
 251         negate = 0;
 252         TRACE(("pipeline: entered\n"));
 253         while (readtoken() == TNOT)
 254                 negate = !negate;
 255         tokpushback++;
 256         n1 = command();
 257         if (readtoken() == TPIPE) {
 258                 pipenode = (union node *)stalloc(sizeof (struct npipe));
 259                 pipenode->type = NPIPE;
 260                 pipenode->npipe.backgnd = 0;
 261                 lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 262                 pipenode->npipe.cmdlist = lp;
 263                 lp->n = n1;
 264                 do {
 265                         prev = lp;
 266                         lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 267                         lp->n = command();
 268                         prev->next = lp;
 269                 } while (readtoken() == TPIPE);
 270                 lp->next = NULL;
 271                 n1 = pipenode;
 272         }
 273         tokpushback++;
 274         if (negate) {
 275                 n2 = (union node *)stalloc(sizeof (struct nnot));
 276                 n2->type = NNOT;
 277                 n2->nnot.com = n1;
 278                 return n2;
 279         } else
 280                 return n1;
 281 }
 282
 283
 284
 285 STATIC union node *
 286 command(void)
 287 {
 288         union node *n1, *n2;
 289         union node *ap, **app;
 290         union node *cp, **cpp;
 291         union node *redir, **rpp;
 292         int t, negate = 0;
 293
 294         checkkwd = 2;
 295         redir = NULL;
 296         n1 = NULL;
 297         rpp = &redir;
 298
 299         /* Check for redirection which may precede command */
 300         while (readtoken() == TREDIR) {
 301                 *rpp = n2 = redirnode;
 302                 rpp = &n2->nfile.next;
 303                 parsefname();
 304         }
 305         tokpushback++;
 306
 307         while (readtoken() == TNOT) {
 308                 TRACE(("command: TNOT recognized\n"));
 309                 negate = !negate;
 310         }
 311         tokpushback++;
 312
 313         switch (readtoken()) {
 314         case TIF:
 315                 n1 = (union node *)stalloc(sizeof (struct nif));
 316                 n1->type = NIF;
 317                 if ((n1->nif.test = list(0)) == NULL)
 318                         synexpect(-1);
 319                 if (readtoken() != TTHEN)
 320                         synexpect(TTHEN);
 321                 n1->nif.ifpart = list(0);
 322                 n2 = n1;
 323                 while (readtoken() == TELIF) {
 324                         n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
 325                         n2 = n2->nif.elsepart;
 326                         n2->type = NIF;
 327                         if ((n2->nif.test = list(0)) == NULL)
 328                                 synexpect(-1);
 329                         if (readtoken() != TTHEN)
 330                                 synexpect(TTHEN);
 331                         n2->nif.ifpart = list(0);
 332                 }
 333                 if (lasttoken == TELSE)
 334                         n2->nif.elsepart = list(0);
 335                 else {
 336                         n2->nif.elsepart = NULL;
 337                         tokpushback++;
 338                 }
 339                 if (readtoken() != TFI)
 340                         synexpect(TFI);
 341                 checkkwd = 1;
 342                 break;
 343         case TWHILE:
 344         case TUNTIL: {
 345                 int got;
 346                 n1 = (union node *)stalloc(sizeof (struct nbinary));
 347                 n1->type = (lasttoken == TWHILE)? NWHILE : NUNTIL;
 348                 if ((n1->nbinary.ch1 = list(0)) == NULL)
 349                         synexpect(-1);
 350                 if ((got=readtoken()) != TDO) {
 351 TRACE(("expecting DO got %s %s\n", tokname[got], got == TWORD ? wordtext : ""));
 352                         synexpect(TDO);
 353                 }
 354                 n1->nbinary.ch2 = list(0);
 355                 if (readtoken() != TDONE)
 356                         synexpect(TDONE);
 357                 checkkwd = 1;
 358                 break;
 359         }
 360         case TFOR:
 361                 if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
 362                         synerror("Bad for loop variable");
 363                 n1 = (union node *)stalloc(sizeof (struct nfor));
 364                 n1->type = NFOR;
 365                 n1->nfor.var = wordtext;
 366                 if (readtoken() == TWORD && ! quoteflag && equal(wordtext, "in")) {
 367                         app = &ap;
 368                         while (readtoken() == TWORD) {
 369                                 n2 = (union node *)stalloc(sizeof (struct narg));
 370                                 n2->type = NARG;
 371                                 n2->narg.text = wordtext;
 372                                 n2->narg.backquote = backquotelist;
 373                                 *app = n2;
 374                                 app = &n2->narg.next;
 375                         }
 376                         *app = NULL;
 377                         n1->nfor.args = ap;
 378                         if (lasttoken != TNL && lasttoken != TSEMI)
 379                                 synexpect(-1);
 380                 } else {
 381                         static char argvars[5] = {
 382                                 CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'
 383                         };
 384                         n2 = (union node *)stalloc(sizeof (struct narg));
 385                         n2->type = NARG;
 386                         n2->narg.text = argvars;
 387                         n2->narg.backquote = NULL;
 388                         n2->narg.next = NULL;
 389                         n1->nfor.args = n2;
 390                         /*
 391                          * Newline or semicolon here is optional (but note
 392                          * that the original Bourne shell only allowed NL).
 393                          */
 394                         if (lasttoken != TNL && lasttoken != TSEMI)
 395                                 tokpushback++;
 396                 }
 397                 checkkwd = 2;
 398                 if ((t = readtoken()) == TDO)
 399                         t = TDONE;
 400                 else if (t == TBEGIN)
 401                         t = TEND;
 402                 else
 403                         synexpect(-1);
 404                 n1->nfor.body = list(0);
 405                 if (readtoken() != t)
 406                         synexpect(t);
 407                 checkkwd = 1;
 408                 break;
 409         case TCASE:
 410                 n1 = (union node *)stalloc(sizeof (struct ncase));
 411                 n1->type = NCASE;
 412                 if (readtoken() != TWORD)
 413                         synexpect(TWORD);
 414                 n1->ncase.expr = n2 = (union node *)stalloc(sizeof (struct narg));
 415                 n2->type = NARG;
 416                 n2->narg.text = wordtext;
 417                 n2->narg.backquote = backquotelist;
 418                 n2->narg.next = NULL;
 419                 while (readtoken() == TNL);
 420                 if (lasttoken != TWORD || ! equal(wordtext, "in"))
 421                         synerror("expecting \"in\"");
 422                 cpp = &n1->ncase.cases;
 423                 noaliases = 1;  /* turn off alias expansion */
 424                 checkkwd = 2, readtoken();
 425                 while (lasttoken != TESAC) {
 426                         *cpp = cp = (union node *)stalloc(sizeof (struct nclist));
 427                         cp->type = NCLIST;
 428                         app = &cp->nclist.pattern;
 429                         if (lasttoken == TLP)
 430                                 readtoken();
 431                         for (;;) {
 432                                 *app = ap = (union node *)stalloc(sizeof (struct narg));
 433                                 ap->type = NARG;
 434                                 ap->narg.text = wordtext;
 435                                 ap->narg.backquote = backquotelist;
 436                                 if (checkkwd = 2, readtoken() != TPIPE)
 437                                         break;
 438                                 app = &ap->narg.next;
 439                                 readtoken();
 440                         }
 441                         ap->narg.next = NULL;
 442                         if (lasttoken != TRP)
 443                                 noaliases = 0, synexpect(TRP);
 444                         cp->nclist.body = list(0);
 445
 446                         checkkwd = 2;
 447                         if ((t = readtoken()) != TESAC) {
 448                                 if (t != TENDCASE)
 449                                         noaliases = 0, synexpect(TENDCASE);
 450                                 else
 451                                         checkkwd = 2, readtoken();
 452                         }
 453                         cpp = &cp->nclist.next;
 454                 }
 455                 noaliases = 0;  /* reset alias expansion */
 456                 *cpp = NULL;
 457                 checkkwd = 1;
 458                 break;
 459         case TLP:
 460                 n1 = (union node *)stalloc(sizeof (struct nredir));
 461                 n1->type = NSUBSHELL;
 462                 n1->nredir.n = list(0);
 463                 n1->nredir.redirect = NULL;
 464                 if (readtoken() != TRP)
 465                         synexpect(TRP);
 466                 checkkwd = 1;
 467                 break;
 468         case TBEGIN:
 469                 n1 = list(0);
 470                 if (readtoken() != TEND)
 471                         synexpect(TEND);
 472                 checkkwd = 1;
 473                 break;
 474         /* Handle an empty command like other simple commands.  */
 475         case TSEMI:
 476         case TAND:
 477         case TOR:
 478                 /*
 479                  * An empty command before a ; doesn't make much sense, and
 480                  * should certainly be disallowed in the case of `if ;'.
 481                  */
 482                 if (!redir)
 483                         synexpect(-1);
 484         case TNL:
 485         case TEOF:
 486         case TWORD:
 487         case TRP:
 488                 tokpushback++;
 489                 n1 = simplecmd(rpp, redir);
 490                 goto checkneg;
 491         default:
 492                 synexpect(-1);
 493         }
 494
 495         /* Now check for redirection which may follow command */
 496         while (readtoken() == TREDIR) {
 497                 *rpp = n2 = redirnode;
 498                 rpp = &n2->nfile.next;
 499                 parsefname();
 500         }
 501         tokpushback++;
 502         *rpp = NULL;
 503         if (redir) {
 504                 if (n1->type != NSUBSHELL) {
 505                         n2 = (union node *)stalloc(sizeof (struct nredir));
 506                         n2->type = NREDIR;
 507                         n2->nredir.n = n1;
 508                         n1 = n2;
 509                 }
 510                 n1->nredir.redirect = redir;
 511         }
 512
 513 checkneg:
 514         if (negate) {
 515                 n2 = (union node *)stalloc(sizeof (struct nnot));
 516                 n2->type = NNOT;
 517                 n2->nnot.com = n1;
 518                 return n2;
 519         }
 520         else
 521                 return n1;
 522 }
 523
 524
 525 STATIC union node *
 526 simplecmd(union node **rpp, union node *redir)
 527 {
 528         union node *args, **app;
 529         union node **orig_rpp = rpp;
 530         union node *n = NULL, *n2;
 531         int negate = 0;
 532
 533         /* If we don't have any redirections already, then we must reset */
 534         /* rpp to be the address of the local redir variable.  */
 535         if (redir == 0)
 536                 rpp = &redir;
 537
 538         args = NULL;
 539         app = &args;
 540         /*
 541          * We save the incoming value, because we need this for shell
 542          * functions.  There can not be a redirect or an argument between
 543          * the function name and the open parenthesis.
 544          */
 545         orig_rpp = rpp;
 546
 547         while (readtoken() == TNOT) {
 548                 TRACE(("command: TNOT recognized\n"));
 549                 negate = !negate;
 550         }
 551         tokpushback++;
 552
 553         for (;;) {
 554                 if (readtoken() == TWORD) {
 555                         n = (union node *)stalloc(sizeof (struct narg));
 556                         n->type = NARG;
 557                         n->narg.text = wordtext;
 558                         n->narg.backquote = backquotelist;
 559                         *app = n;
 560                         app = &n->narg.next;
 561                 } else if (lasttoken == TREDIR) {
 562                         *rpp = n = redirnode;
 563                         rpp = &n->nfile.next;
 564                         parsefname();   /* read name of redirection file */
 565                 } else if (lasttoken == TLP && app == &args->narg.next
 566                                             && rpp == orig_rpp) {
 567                         /* We have a function */
 568                         if (readtoken() != TRP)
 569                                 synexpect(TRP);
 570 #ifdef notdef
 571                         if (! goodname(n->narg.text))
 572                                 synerror("Bad function name");
 573 #endif
 574                         n->type = NDEFUN;
 575                         n->narg.next = command();
 576                         goto checkneg;
 577                 } else {
 578                         tokpushback++;
 579                         break;
 580                 }
 581         }
 582         *app = NULL;
 583         *rpp = NULL;
 584         n = (union node *)stalloc(sizeof (struct ncmd));
 585         n->type = NCMD;
 586         n->ncmd.backgnd = 0;
 587         n->ncmd.args = args;
 588         n->ncmd.redirect = redir;
 589
 590 checkneg:
 591         if (negate) {
 592                 n2 = (union node *)stalloc(sizeof (struct nnot));
 593                 n2->type = NNOT;
 594                 n2->nnot.com = n;
 595                 return n2;
 596         }
 597         else
 598                 return n;
 599 }
 600
 601 STATIC union node *
 602 makename(void)
 603 {
 604         union node *n;
 605
 606         n = (union node *)stalloc(sizeof (struct narg));
 607         n->type = NARG;
 608         n->narg.next = NULL;
 609         n->narg.text = wordtext;
 610         n->narg.backquote = backquotelist;
 611         return n;
 612 }
 613
 614 void
 615 fixredir(union node *n, const char *text, int err)
 616 {
 617         TRACE(("Fix redir %s %d\n", text, err));
 618         if (!err)
 619                 n->ndup.vname = NULL;
 620
 621         if (is_digit(text[0]) && text[1] == '\0')
 622                 n->ndup.dupfd = digit_val(text[0]);
 623         else if (text[0] == '-' && text[1] == '\0')
 624                 n->ndup.dupfd = -1;
 625         else {
 626
 627                 if (err)
 628                         synerror("Bad fd number");
 629                 else
 630                         n->ndup.vname = makename();
 631         }
 632 }
 633
 634
 635 STATIC void
 636 parsefname(void)
 637 {
 638         union node *n = redirnode;
 639
 640         if (readtoken() != TWORD)
 641                 synexpect(-1);
 642         if (n->type == NHERE) {
 643                 struct heredoc *here = heredoc;
 644                 struct heredoc *p;
 645                 int i;
 646
 647                 if (quoteflag == 0)
 648                         n->type = NXHERE;
 649                 TRACE(("Here document %d\n", n->type));
 650                 if (here->striptabs) {
 651                         while (*wordtext == '\t')
 652                                 wordtext++;
 653                 }
 654                 if (! noexpand(wordtext) || (i = strlen(wordtext)) == 0 || i > EOFMARKLEN)
 655                         synerror("Illegal eof marker for << redirection");
 656                 rmescapes(wordtext);
 657                 here->eofmark = wordtext;
 658                 here->next = NULL;
 659                 if (heredoclist == NULL)
 660                         heredoclist = here;
 661                 else {
 662                         for (p = heredoclist ; p->next ; p = p->next);
 663                         p->next = here;
 664                 }
 665         } else if (n->type == NTOFD || n->type == NFROMFD) {
 666                 fixredir(n, wordtext, 0);
 667         } else {
 668                 n->nfile.fname = makename();
 669         }
 670 }
 671
 672
 673 /*
 674  * Input any here documents.
 675  */
 676
 677 STATIC void
 678 parseheredoc(void)
 679 {
 680         struct heredoc *here;
 681         union node *n;
 682
 683         while (heredoclist) {
 684                 here = heredoclist;
 685                 heredoclist = here->next;
 686                 if (needprompt) {
 687                         setprompt(2);
 688                         needprompt = 0;
 689                 }
 690                 readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
 691                                 here->eofmark, here->striptabs);
 692                 n = (union node *)stalloc(sizeof (struct narg));
 693                 n->narg.type = NARG;
 694                 n->narg.next = NULL;
 695                 n->narg.text = wordtext;
 696                 n->narg.backquote = backquotelist;
 697                 here->here->nhere.doc = n;
 698         }
 699 }
 700
 701 STATIC int
 702 peektoken(void)
 703 {
 704         int t;
 705
 706         t = readtoken();
 707         tokpushback++;
 708         return (t);
 709 }
 710
 711 STATIC int
 712 readtoken(void)
 713 {
 714         int t;
 715         int savecheckkwd = checkkwd;
 716         struct alias *ap;
 717 #ifdef DEBUG
 718         int alreadyseen = tokpushback;
 719 #endif
 720
 721         top:
 722         t = xxreadtoken();
 723
 724         if (checkkwd) {
 725                 /*
 726                  * eat newlines
 727                  */
 728                 if (checkkwd == 2) {
 729                         checkkwd = 0;
 730                         while (t == TNL) {
 731                                 parseheredoc();
 732                                 t = xxreadtoken();
 733                         }
 734                 } else
 735                         checkkwd = 0;
 736                 /*
 737                  * check for keywords and aliases
 738                  */
 739                 if (t == TWORD && !quoteflag)
 740                 {
 741                         const char * const *pp;
 742
 743                         for (pp = parsekwd; *pp; pp++) {
 744                                 if (**pp == *wordtext && equal(*pp, wordtext))
 745                                 {
 746                                         lasttoken = t = pp - parsekwd + KWDOFFSET;
 747                                         TRACE(("keyword %s recognized\n", tokname[t]));
 748                                         goto out;
 749                                 }
 750                         }
 751                         if (noaliases == 0 &&
 752                             (ap = lookupalias(wordtext, 1)) != NULL) {
 753                                 pushstring(ap->val, strlen(ap->val), ap);
 754                                 checkkwd = savecheckkwd;
 755                                 goto top;
 756                         }
 757                 }
 758 out:
 759                 checkkwd = (t == TNOT) ? savecheckkwd : 0;
 760         }
 761 #ifdef DEBUG
 762         if (!alreadyseen)
 763             TRACE(("token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 764         else
 765             TRACE(("reread token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 766 #endif
 767         return (t);
 768 }
 769
 770
 771 /*
 772  * Read the next input token.
 773  * If the token is a word, we set backquotelist to the list of cmds in
 774  *      backquotes.  We set quoteflag to true if any part of the word was
 775  *      quoted.
 776  * If the token is TREDIR, then we set redirnode to a structure containing
 777  *      the redirection.
 778  * In all cases, the variable startlinno is set to the number of the line
 779  *      on which the token starts.
 780  *
 781  * [Change comment:  here documents and internal procedures]
 782  * [Readtoken shouldn't have any arguments.  Perhaps we should make the
 783  *  word parsing code into a separate routine.  In this case, readtoken
 784  *  doesn't need to have any internal procedures, but parseword does.
 785  *  We could also make parseoperator in essence the main routine, and
 786  *  have parseword (readtoken1?) handle both words and redirection.]
 787  */
 788
 789 #define RETURN(token)   return lasttoken = token
 790
 791 STATIC int
 792 xxreadtoken(void)
 793 {
 794         int c;
 795
 796         if (tokpushback) {
 797                 tokpushback = 0;
 798                 return lasttoken;
 799         }
 800         if (needprompt) {
 801                 setprompt(2);
 802                 needprompt = 0;
 803         }
 804         startlinno = plinno;
 805         for (;;) {      /* until token or start of word found */
 806                 c = pgetc_macro();
 807                 if (c == ' ' || c == '\t')
 808                         continue;               /* quick check for white space first */
 809                 switch (c) {
 810                 case ' ': case '\t':
 811                         continue;
 812                 case '#':
 813                         while ((c = pgetc()) != '\n' && c != PEOF);
 814                         pungetc();
 815                         continue;
 816                 case '\\':
 817                         if (pgetc() == '\n') {
 818                                 startlinno = ++plinno;
 819                                 if (doprompt)
 820                                         setprompt(2);
 821                                 else
 822                                         setprompt(0);
 823                                 continue;
 824                         }
 825                         pungetc();
 826                         goto breakloop;
 827                 case '\n':
 828                         plinno++;
 829                         needprompt = doprompt;
 830                         RETURN(TNL);
 831                 case PEOF:
 832                         RETURN(TEOF);
 833                 case '&':
 834                         if (pgetc() == '&')
 835                                 RETURN(TAND);
 836                         pungetc();
 837                         RETURN(TBACKGND);
 838                 case '|':
 839                         if (pgetc() == '|')
 840                                 RETURN(TOR);
 841                         pungetc();
 842                         RETURN(TPIPE);
 843                 case ';':
 844                         if (pgetc() == ';')
 845                                 RETURN(TENDCASE);
 846                         pungetc();
 847                         RETURN(TSEMI);
 848                 case '(':
 849                         RETURN(TLP);
 850                 case ')':
 851                         RETURN(TRP);
 852                 default:
 853                         goto breakloop;
 854                 }
 855         }
 856 breakloop:
 857         return readtoken1(c, BASESYNTAX, (char *)NULL, 0);
 858 #undef RETURN
 859 }
 860
 861
 862
 863 /*
 864  * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
 865  * is not NULL, read a here document.  In the latter case, eofmark is the
 866  * word which marks the end of the document and striptabs is true if
 867  * leading tabs should be stripped from the document.  The argument firstc
 868  * is the first character of the input token or document.
 869  *
 870  * Because C does not have internal subroutines, I have simulated them
 871  * using goto's to implement the subroutine linkage.  The following macros
 872  * will run code that appears at the end of readtoken1.
 873  */
 874
 875 #define CHECKEND()      {goto checkend; checkend_return:;}
 876 #define PARSEREDIR()    {goto parseredir; parseredir_return:;}
 877 #define PARSESUB()      {goto parsesub; parsesub_return:;}
 878 #define PARSEBACKQOLD() {oldstyle = 1; goto parsebackq; parsebackq_oldreturn:;}
 879 #define PARSEBACKQNEW() {oldstyle = 0; goto parsebackq; parsebackq_newreturn:;}
 880 #define PARSEARITH()    {goto parsearith; parsearith_return:;}
 881
 882 STATIC int
 883 readtoken1(int firstc, char const *syntax, char *eofmark, int striptabs)
 884 {
 885         int c = firstc;
 886         char *out;
 887         int len;
 888         char line[EOFMARKLEN + 1];
 889         struct nodelist *bqlist;
 890         int quotef;
 891         int dblquote;
 892         int varnest;    /* levels of variables expansion */
 893         int arinest;    /* levels of arithmetic expansion */
 894         int parenlevel; /* levels of parens in arithmetic */
 895         int oldstyle;
 896         char const *prevsyntax; /* syntax before arithmetic */
 897         int synentry;
 898 #if __GNUC__
 899         /* Avoid longjmp clobbering */
 900         (void) &out;
 901         (void) &quotef;
 902         (void) &dblquote;
 903         (void) &varnest;
 904         (void) &arinest;
 905         (void) &parenlevel;
 906         (void) &oldstyle;
 907         (void) &prevsyntax;
 908         (void) &syntax;
 909         (void) &synentry;
 910 #endif
 911
 912         startlinno = plinno;
 913         dblquote = 0;
 914         if (syntax == DQSYNTAX)
 915                 dblquote = 1;
 916         quotef = 0;
 917         bqlist = NULL;
 918         varnest = 0;
 919         arinest = 0;
 920         parenlevel = 0;
 921
 922         STARTSTACKSTR(out);
 923         loop: { /* for each line, until end of word */
 924                 CHECKEND();     /* set c to PEOF if at end of here document */
 925                 for (;;) {      /* until end of line or end of word */
 926                         CHECKSTRSPACE(3, out);  /* permit 3 calls to USTPUTC */
 927
 928                         synentry = syntax[c];
 929
 930                         switch(synentry) {
 931                         case CNL:       /* '\n' */
 932                                 if (syntax == BASESYNTAX)
 933                                         goto endword;   /* exit outer loop */
 934                                 USTPUTC(c, out);
 935                                 plinno++;
 936                                 if (doprompt)
 937                                         setprompt(2);
 938                                 else
 939                                         setprompt(0);
 940                                 c = pgetc();
 941                                 goto loop;              /* continue outer loop */
 942                         case CWORD:
 943                                 USTPUTC(c, out);
 944                                 break;
 945                         case CCTL:
 946                                 if (eofmark == NULL || dblquote)
 947                                         USTPUTC(CTLESC, out);
 948                                 USTPUTC(c, out);
 949                                 break;
 950                         case CBACK:     /* backslash */
 951                                 c = pgetc();
 952                                 if (c == PEOF) {
 953                                         USTPUTC('\\', out);
 954                                         pungetc();
 955                                 } else if (c == '\n') {
 956                                         plinno++;
 957                                         if (doprompt)
 958                                                 setprompt(2);
 959                                         else
 960                                                 setprompt(0);
 961                                 } else {
 962                                         if (dblquote && c != '\\' &&
 963                                             c != '`' && c != '$' &&
 964                                             (c != '"' || eofmark != NULL))
 965                                                 USTPUTC('\\', out);
 966                                         if (SQSYNTAX[c] == CCTL)
 967                                                 USTPUTC(CTLESC, out);
 968                                         else if (eofmark == NULL)
 969                                                 USTPUTC(CTLQUOTEMARK, out);
 970                                         USTPUTC(c, out);
 971                                         quotef++;
 972                                 }
 973                                 break;
 974                         case CSQUOTE:
 975                                 if (eofmark == NULL)
 976                                         USTPUTC(CTLQUOTEMARK, out);
 977                                 syntax = SQSYNTAX;
 978                                 break;
 979                         case CDQUOTE:
 980                                 if (eofmark == NULL)
 981                                         USTPUTC(CTLQUOTEMARK, out);
 982                                 syntax = DQSYNTAX;
 983                                 dblquote = 1;
 984                                 break;
 985                         case CENDQUOTE:
 986                                 if (eofmark != NULL && arinest == 0 &&
 987                                     varnest == 0) {
 988                                         USTPUTC(c, out);
 989                                 } else {
 990                                         if (arinest) {
 991                                                 syntax = ARISYNTAX;
 992                                                 dblquote = 0;
 993                                         } else if (eofmark == NULL) {
 994                                                 syntax = BASESYNTAX;
 995                                                 dblquote = 0;
 996                                         }
 997                                         quotef++;
 998                                 }
 999                                 break;
1000                         case CVAR:      /* '$' */
1001                                 PARSESUB();             /* parse substitution */
1002                                 break;
1003                         case CENDVAR:   /* '}' */
1004                                 if (varnest > 0) {
1005                                         varnest--;
1006                                         USTPUTC(CTLENDVAR, out);
1007                                 } else {
1008                                         USTPUTC(c, out);
1009                                 }
1010                                 break;
1011                         case CLP:       /* '(' in arithmetic */
1012                                 parenlevel++;
1013                                 USTPUTC(c, out);
1014                                 break;
1015                         case CRP:       /* ')' in arithmetic */
1016                                 if (parenlevel > 0) {
1017                                         USTPUTC(c, out);
1018                                         --parenlevel;
1019                                 } else {
1020                                         if (pgetc() == ')') {
1021                                                 if (--arinest == 0) {
1022                                                         USTPUTC(CTLENDARI, out);
1023                                                         syntax = prevsyntax;
1024                                                         if (syntax == DQSYNTAX)
1025                                                                 dblquote = 1;
1026                                                         else
1027                                                                 dblquote = 0;
1028                                                 } else
1029                                                         USTPUTC(')', out);
1030                                         } else {
1031                                                 /*
1032                                                  * unbalanced parens
1033                                                  *  (don't 2nd guess - no error)
1034                                                  */
1035                                                 pungetc();
1036                                                 USTPUTC(')', out);
1037                                         }
1038                                 }
1039                                 break;
1040                         case CBQUOTE:   /* '`' */
1041                                 PARSEBACKQOLD();
1042                                 break;
1043                         case CEOF:
1044                                 goto endword;           /* exit outer loop */
1045                         default:
1046                                 if (varnest == 0)
1047                                         goto endword;   /* exit outer loop */
1048                                 USTPUTC(c, out);
1049                         }
1050                         c = pgetc_macro();
1051                 }
1052         }
1053 endword:
1054         if (syntax == ARISYNTAX)
1055                 synerror("Missing '))'");
1056         if (syntax != BASESYNTAX && ! parsebackquote && eofmark == NULL)
1057                 synerror("Unterminated quoted string");
1058         if (varnest != 0) {
1059                 startlinno = plinno;
1060                 synerror("Missing '}'");
1061         }
1062         USTPUTC('\0', out);
1063         len = out - stackblock();
1064         out = stackblock();
1065         if (eofmark == NULL) {
1066                 if ((c == '>' || c == '<')
1067                  && quotef == 0
1068                  && len <= 2
1069                  && (*out == '\0' || is_digit(*out))) {
1070                         PARSEREDIR();
1071                         return lasttoken = TREDIR;
1072                 } else {
1073                         pungetc();
1074                 }
1075         }
1076         quoteflag = quotef;
1077         backquotelist = bqlist;
1078         grabstackblock(len);
1079         wordtext = out;
1080         return lasttoken = TWORD;
1081 /* end of readtoken routine */
1082
1083
1084
1085 /*
1086  * Check to see whether we are at the end of the here document.  When this
1087  * is called, c is set to the first character of the next input line.  If
1088  * we are at the end of the here document, this routine sets the c to PEOF.
1089  */
1090
1091 checkend: {
1092         if (eofmark) {
1093                 if (striptabs) {
1094                         while (c == '\t')
1095                                 c = pgetc();
1096                 }
1097                 if (c == *eofmark) {
1098                         if (pfgets(line, sizeof line) != NULL) {
1099                                 char *p, *q;
1100
1101                                 p = line;
1102                                 for (q = eofmark + 1 ; *q && *p == *q ; p++, q++);
1103                                 if (*p == '\n' && *q == '\0') {
1104                                         c = PEOF;
1105                                         plinno++;
1106                                         needprompt = doprompt;
1107                                 } else {
1108                                         pushstring(line, strlen(line), NULL);
1109                                 }
1110                         }
1111                 }
1112         }
1113         goto checkend_return;
1114 }
1115
1116
1117 /*
1118  * Parse a redirection operator.  The variable "out" points to a string
1119  * specifying the fd to be redirected.  The variable "c" contains the
1120  * first character of the redirection operator.
1121  */
1122
1123 parseredir: {
1124         char fd = *out;
1125         union node *np;
1126
1127         np = (union node *)stalloc(sizeof (struct nfile));
1128         if (c == '>') {
1129                 np->nfile.fd = 1;
1130                 c = pgetc();
1131                 if (c == '>')
1132                         np->type = NAPPEND;
1133                 else if (c == '&')
1134                         np->type = NTOFD;
1135                 else if (c == '|')
1136                         np->type = NCLOBBER;
1137                 else {
1138                         np->type = NTO;
1139                         pungetc();
1140                 }
1141         } else {        /* c == '<' */
1142                 np->nfile.fd = 0;
1143                 c = pgetc();
1144                 if (c == '<') {
1145                         if (sizeof (struct nfile) != sizeof (struct nhere)) {
1146                                 np = (union node *)stalloc(sizeof (struct nhere));
1147                                 np->nfile.fd = 0;
1148                         }
1149                         np->type = NHERE;
1150                         heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
1151                         heredoc->here = np;
1152                         if ((c = pgetc()) == '-') {
1153                                 heredoc->striptabs = 1;
1154                         } else {
1155                                 heredoc->striptabs = 0;
1156                                 pungetc();
1157                         }
1158                 } else if (c == '&')
1159                         np->type = NFROMFD;
1160                 else if (c == '>')
1161                         np->type = NFROMTO;
1162                 else {
1163                         np->type = NFROM;
1164                         pungetc();
1165                 }
1166         }
1167         if (fd != '\0')
1168                 np->nfile.fd = digit_val(fd);
1169         redirnode = np;
1170         goto parseredir_return;
1171 }
1172
1173
1174 /*
1175  * Parse a substitution.  At this point, we have read the dollar sign
1176  * and nothing else.
1177  */
1178
1179 parsesub: {
1180         int subtype;
1181         int typeloc;
1182         int flags;
1183         char *p;
1184         static const char types[] = "}-+?=";
1185        int bracketed_name = 0; /* used to handle ${[0-9]*} variables */
1186
1187         c = pgetc();
1188         if (c != '(' && c != '{' && (is_eof(c) || !is_name(c)) &&
1189             !is_special(c)) {
1190                 USTPUTC('$', out);
1191                 pungetc();
1192         } else if (c == '(') {  /* $(command) or $((arith)) */
1193                 if (pgetc() == '(') {
1194                         PARSEARITH();
1195                 } else {
1196                         pungetc();
1197                         PARSEBACKQNEW();
1198                 }
1199         } else {
1200                 USTPUTC(CTLVAR, out);
1201                 typeloc = out - stackblock();
1202                 USTPUTC(VSNORMAL, out);
1203                 subtype = VSNORMAL;
1204                 if (c == '{') {
1205                         bracketed_name = 1;
1206                         c = pgetc();
1207                         if (c == '#') {
1208                                 if ((c = pgetc()) == '}')
1209                                         c = '#';
1210                                 else
1211                                         subtype = VSLENGTH;
1212                         }
1213                         else
1214                                 subtype = 0;
1215                 }
1216                 if (!is_eof(c) && is_name(c)) {
1217                         do {
1218                                 STPUTC(c, out);
1219                                 c = pgetc();
1220                         } while (!is_eof(c) && is_in_name(c));
1221                 } else if (is_digit(c)) {
1222                         if (bracketed_name) {
1223                                 do {
1224                                         STPUTC(c, out);
1225                                         c = pgetc();
1226                                 } while (is_digit(c));
1227                         } else {
1228                                 STPUTC(c, out);
1229                                 c = pgetc();
1230                         }
1231                 } else {
1232                         if (! is_special(c)) {
1233                                 subtype = VSERROR;
1234                                 if (c == '}')
1235                                         pungetc();
1236                                 else
1237                                         USTPUTC(c, out);
1238                         } else {
1239                                 USTPUTC(c, out);
1240                                 c = pgetc();
1241                         }
1242                 }
1243                 flags = 0;
1244                 if (subtype == 0) {
1245                         switch (c) {
1246                         case ':':
1247                                 flags = VSNUL;
1248                                 c = pgetc();
1249                                 /*FALLTHROUGH*/
1250                         default:
1251                                 p = strchr(types, c);
1252                                 if (p == NULL) {
1253                                         if (flags == VSNUL)
1254                                                 STPUTC(':', out);
1255                                         STPUTC(c, out);
1256                                         subtype = VSERROR;
1257                                 } else
1258                                         subtype = p - types + VSNORMAL;
1259                                 break;
1260                         case '%':
1261                         case '#':
1262                                 {
1263                                         int cc = c;
1264                                         subtype = c == '#' ? VSTRIMLEFT :
1265                                                              VSTRIMRIGHT;
1266                                         c = pgetc();
1267                                         if (c == cc)
1268                                                 subtype++;
1269                                         else
1270                                                 pungetc();
1271                                         break;
1272                                 }
1273                         }
1274                 } else if (subtype != VSERROR) {
1275                         pungetc();
1276                 }
1277                 STPUTC('=', out);
1278                 if (subtype != VSLENGTH && (dblquote || arinest))
1279                         flags |= VSQUOTE;
1280                 *(stackblock() + typeloc) = subtype | flags;
1281                 if (subtype != VSNORMAL)
1282                         varnest++;
1283         }
1284         goto parsesub_return;
1285 }
1286
1287
1288 /*
1289  * Called to parse command substitutions.  Newstyle is set if the command
1290  * is enclosed inside $(...); nlpp is a pointer to the head of the linked
1291  * list of commands (passed by reference), and savelen is the number of
1292  * characters on the top of the stack which must be preserved.
1293  */
1294
1295 parsebackq: {
1296         struct nodelist **nlpp;
1297         int savepbq;
1298         union node *n;
1299         char *volatile str;
1300         struct jmploc jmploc;
1301         struct jmploc *volatile savehandler;
1302         int savelen;
1303         int saveprompt;
1304 #if __GNUC__
1305         /* Avoid longjmp clobbering */
1306         (void) &saveprompt;
1307 #endif
1308
1309         savepbq = parsebackquote;
1310         if (setjmp(jmploc.loc)) {
1311                 if (str)
1312                         ckfree(str);
1313                 parsebackquote = 0;
1314                 handler = savehandler;
1315                 longjmp(handler->loc, 1);
1316         }
1317         INTOFF;
1318         str = NULL;
1319         savelen = out - stackblock();
1320         if (savelen > 0) {
1321                 str = ckmalloc(savelen);
1322                 memcpy(str, stackblock(), savelen);
1323         }
1324         savehandler = handler;
1325         handler = &jmploc;
1326         INTON;
1327         if (oldstyle) {
1328                 /* We must read until the closing backquote, giving special
1329                    treatment to some slashes, and then push the string and
1330                    reread it as input, interpreting it normally.  */
1331                 char *pout;
1332                 int pc;
1333                 int psavelen;
1334                 char *pstr;
1335
1336
1337                 STARTSTACKSTR(pout);
1338                 for (;;) {
1339                         if (needprompt) {
1340                                 setprompt(2);
1341                                 needprompt = 0;
1342                         }
1343                         switch (pc = pgetc()) {
1344                         case '`':
1345                                 goto done;
1346
1347                         case '\\':
1348                                 if ((pc = pgetc()) == '\n') {
1349                                         plinno++;
1350                                         if (doprompt)
1351                                                 setprompt(2);
1352                                         else
1353                                                 setprompt(0);
1354                                         /*
1355                                          * If eating a newline, avoid putting
1356                                          * the newline into the new character
1357                                          * stream (via the STPUTC after the
1358                                          * switch).
1359                                          */
1360                                         continue;
1361                                 }
1362                                 if (pc != '\\' && pc != '`' && pc != '$'
1363                                     && (!dblquote || pc != '"'))
1364                                         STPUTC('\\', pout);
1365                                 break;
1366
1367                         case '\n':
1368                                 plinno++;
1369                                 needprompt = doprompt;
1370                                 break;
1371
1372                         case PEOF:
1373                                 startlinno = plinno;
1374                                 synerror("EOF in backquote substitution");
1375                                 break;
1376
1377                         default:
1378                                 break;
1379                         }
1380                         STPUTC(pc, pout);
1381                 }
1382 done:
1383                 STPUTC('\0', pout);
1384                 psavelen = pout - stackblock();
1385                 if (psavelen > 0) {
1386                         pstr = ckmalloc(psavelen);
1387                         memcpy(pstr, stackblock(), psavelen);
1388                         setinputstring(pstr, 1);
1389                 }
1390         }
1391         nlpp = &bqlist;
1392         while (*nlpp)
1393                 nlpp = &(*nlpp)->next;
1394         *nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
1395         (*nlpp)->next = NULL;
1396         parsebackquote = oldstyle;
1397
1398         if (oldstyle) {
1399                 saveprompt = doprompt;
1400                 doprompt = 0;
1401         }
1402
1403         n = list(0);
1404
1405         if (oldstyle)
1406                 doprompt = saveprompt;
1407         else {
1408                 if (readtoken() != TRP)
1409                         synexpect(TRP);
1410         }
1411
1412         (*nlpp)->n = n;
1413         if (oldstyle) {
1414                 /*
1415                  * Start reading from old file again, ignoring any pushed back
1416                  * tokens left from the backquote parsing
1417                  */
1418                 popfile();
1419                 tokpushback = 0;
1420         }
1421         while (stackblocksize() <= savelen)
1422                 growstackblock();
1423         STARTSTACKSTR(out);
1424         if (str) {
1425                 memcpy(out, str, savelen);
1426                 STADJUST(savelen, out);
1427                 INTOFF;
1428                 ckfree(str);
1429                 str = NULL;
1430                 INTON;
1431         }
1432         parsebackquote = savepbq;
1433         handler = savehandler;
1434         if (arinest || dblquote)
1435                 USTPUTC(CTLBACKQ | CTLQUOTE, out);
1436         else
1437                 USTPUTC(CTLBACKQ, out);
1438         if (oldstyle)
1439                 goto parsebackq_oldreturn;
1440         else
1441                 goto parsebackq_newreturn;
1442 }
1443
1444 /*
1445  * Parse an arithmetic expansion (indicate start of one and set state)
1446  */
1447 parsearith: {
1448
1449         if (++arinest == 1) {
1450                 prevsyntax = syntax;
1451                 syntax = ARISYNTAX;
1452                 USTPUTC(CTLARI, out);
1453                 if (dblquote)
1454                         USTPUTC('"',out);
1455                 else
1456                         USTPUTC(' ',out);
1457         } else {
1458                 /*
1459                  * we collapse embedded arithmetic expansion to
1460                  * parenthesis, which should be equivalent
1461                  */
1462                 USTPUTC('(', out);
1463         }
1464         goto parsearith_return;
1465 }
1466
1467 } /* end of readtoken */
1468
1469
1470
1471 #ifdef mkinit
1472 RESET {
1473         tokpushback = 0;
1474         checkkwd = 0;
1475 }
1476 #endif
1477
1478 /*
1479  * Returns true if the text contains nothing to expand (no dollar signs
1480  * or backquotes).
1481  */
1482
1483 STATIC int
1484 noexpand(char *text)
1485 {
1486         char *p;
1487         char c;
1488
1489         p = text;
1490         while ((c = *p++) != '\0') {
1491                 if ( c == CTLQUOTEMARK)
1492                         continue;
1493                 if (c == CTLESC)
1494                         p++;
1495                 else if (BASESYNTAX[(int)c] == CCTL)
1496                         return 0;
1497         }
1498         return 1;
1499 }
1500
1501
1502 /*
1503  * Return true if the argument is a legal variable name (a letter or
1504  * underscore followed by zero or more letters, underscores, and digits).
1505  */
1506
1507 int
1508 goodname(char *name)
1509 {
1510         char *p;
1511
1512         p = name;
1513         if (! is_name(*p))
1514                 return 0;
1515         while (*++p) {
1516                 if (! is_in_name(*p))
1517                         return 0;
1518         }
1519         return 1;
1520 }
1521
1522
1523 /*
1524  * Called when an unexpected token is read during the parse.  The argument
1525  * is the token that is expected, or -1 if more than one type of token can
1526  * occur at this point.
1527  */
1528
1529 STATIC void
1530 synexpect(int token)
1531 {
1532         char msg[64];
1533
1534         if (token >= 0) {
1535                 fmtstr(msg, 64, "%s unexpected (expecting %s)",
1536                         tokname[lasttoken], tokname[token]);
1537         } else {
1538                 fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
1539         }
1540         synerror(msg);
1541 }
1542
1543
1544 STATIC void
1545 synerror(const char *msg)
1546 {
1547         if (commandname)
1548                 outfmt(&errout, "%s: %d: ", commandname, startlinno);
1549         outfmt(&errout, "Syntax error: %s\n", msg);
1550         error((char *)NULL);
1551 }
1552
1553 STATIC void
1554 setprompt(int which)
1555 {
1556         whichprompt = which;
1557
1558 #ifndef NO_HISTORY
1559         if (!el)
1560 #endif
1561                 out2str(getprompt(NULL));
1562 }
1563
1564 /*
1565  * called by editline -- any expansions to the prompt
1566  *    should be added here.
1567  */
1568 const char *
1569 getprompt(void *unused __unused)
1570 {
1571         static char ps[PROMPTLEN];
1572         const char *fmt;
1573         int i, j, trim;
1574
1575         /*
1576          * Select prompt format.
1577          */
1578         switch (whichprompt) {
1579         case 0:
1580                 fmt = "";
1581                 break;
1582         case 1:
1583                 fmt = ps1val();
1584                 break;
1585         case 2:
1586                 fmt = ps2val();
1587                 break;
1588         default:
1589                 return "<internal prompt error>";
1590         }
1591
1592         /*
1593          * Format prompt string.
1594          */
1595         for (i = 0; (i < 127) && (*fmt != '\0'); i++, fmt++)
1596                 if (*fmt == '\\')
1597                         switch (*++fmt) {
1598
1599                                 /*
1600                                  * Hostname.
1601                                  *
1602                                  * \h specifies just the local hostname,
1603                                  * \H specifies fully-qualified hostname.
1604                                  */
1605                         case 'h':
1606                         case 'H':
1607                                 ps[i] = '\0';
1608                                 gethostname(&ps[i], PROMPTLEN - i);
1609                                 /* Skip to end of hostname. */
1610                                 trim = (*fmt == 'h') ? '.' : '\0';
1611                                 while ((ps[i+1] != '\0') && (ps[i+1] != trim))
1612                                         i++;
1613                                 break;
1614
1615                                 /*
1616                                  * Working directory.
1617                                  *
1618                                  * \W specifies just the final component,
1619                                  * \w specifies the entire path.
1620                                  */
1621                         case 'W':
1622                         case 'w':
1623                                 ps[i] = '\0';
1624                                 getcwd(&ps[i], PROMPTLEN - i);
1625                                 if (*fmt == 'W') {
1626                                         /* Final path component only. */
1627                                         trim = 1;
1628                                         for (j = i; ps[j] != '\0'; j++)
1629                                           if (ps[j] == '/')
1630                                                 trim = j + 1;
1631                                         memmove(&ps[i], &ps[trim],
1632                                             j - trim + 1);
1633                                 }
1634                                 /* Skip to end of path. */
1635                                 while (ps[i + 1] != '\0')
1636                                         i++;
1637                                 break;
1638
1639                                 /*
1640                                  * Superuser status.
1641                                  *
1642                                  * '$' for normal users, '#' for root.
1643                                  */
1644                         case '$':
1645                                 ps[i] = (geteuid() != 0) ? '$' : '#';
1646                                 break;
1647
1648                                 /*
1649                                  * A literal \.
1650                                  */
1651                         case '\\':
1652                                 ps[i] = '\\';
1653                                 break;
1654
1655                                 /*
1656                                  * Emit unrecognized formats verbatim.
1657                                  */
1658                         default:
1659                                 ps[i++] = '\\';
1660                                 ps[i] = *fmt;
1661                                 break;
1662                         }
1663                 else
1664                         ps[i] = *fmt;
1665         ps[i] = '\0';
1666         return (ps);
1667 }