bin/sh/parser.c

   1 /*-
   2  * Copyright (c) 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Kenneth Almquist.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 4. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #ifndef lint
  34 #if 0
  35 static char sccsid[] = "@(#)parser.c    8.7 (Berkeley) 5/16/95";
  36 #endif
  37 #endif /* not lint */
  38 #include <sys/cdefs.h>
  39 __FBSDID("$FreeBSD$");
  40
  41 #include <stdlib.h>
  42 #include <unistd.h>
  43
  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 STATIC int funclinno;           /* line # where the current function started */
  98
  99 /* XXX When 'noaliases' is set to one, no alias expansion takes place. */
 100 static int noaliases = 0;
 101
 102
 103 STATIC union node *list(int);
 104 STATIC union node *andor(void);
 105 STATIC union node *pipeline(void);
 106 STATIC union node *command(void);
 107 STATIC union node *simplecmd(union node **, union node *);
 108 STATIC union node *makename(void);
 109 STATIC void parsefname(void);
 110 STATIC void parseheredoc(void);
 111 STATIC int peektoken(void);
 112 STATIC int readtoken(void);
 113 STATIC int xxreadtoken(void);
 114 STATIC int readtoken1(int, char const *, char *, int);
 115 STATIC int noexpand(char *);
 116 STATIC void synexpect(int);
 117 STATIC void synerror(char *);
 118 STATIC void setprompt(int);
 119
 120
 121 /*
 122  * Read and parse a command.  Returns NEOF on end of file.  (NULL is a
 123  * valid parse tree indicating a blank line.)
 124  */
 125
 126 union node *
 127 parsecmd(int interact)
 128 {
 129         int t;
 130
 131         tokpushback = 0;
 132         doprompt = interact;
 133         if (doprompt)
 134                 setprompt(1);
 135         else
 136                 setprompt(0);
 137         needprompt = 0;
 138         t = readtoken();
 139         if (t == TEOF)
 140                 return NEOF;
 141         if (t == TNL)
 142                 return NULL;
 143         tokpushback++;
 144         return list(1);
 145 }
 146
 147
 148 STATIC union node *
 149 list(int nlflag)
 150 {
 151         union node *n1, *n2, *n3;
 152         int tok;
 153
 154         checkkwd = 2;
 155         if (nlflag == 0 && tokendlist[peektoken()])
 156                 return NULL;
 157         n1 = NULL;
 158         for (;;) {
 159                 n2 = andor();
 160                 tok = readtoken();
 161                 if (tok == TBACKGND) {
 162                         if (n2->type == NCMD || n2->type == NPIPE) {
 163                                 n2->ncmd.backgnd = 1;
 164                         } else if (n2->type == NREDIR) {
 165                                 n2->type = NBACKGND;
 166                         } else {
 167                                 n3 = (union node *)stalloc(sizeof (struct nredir));
 168                                 n3->type = NBACKGND;
 169                                 n3->nredir.n = n2;
 170                                 n3->nredir.redirect = NULL;
 171                                 n2 = n3;
 172                         }
 173                 }
 174                 if (n1 == NULL) {
 175                         n1 = n2;
 176                 }
 177                 else {
 178                         n3 = (union node *)stalloc(sizeof (struct nbinary));
 179                         n3->type = NSEMI;
 180                         n3->nbinary.ch1 = n1;
 181                         n3->nbinary.ch2 = n2;
 182                         n1 = n3;
 183                 }
 184                 switch (tok) {
 185                 case TBACKGND:
 186                 case TSEMI:
 187                         tok = readtoken();
 188                         /* FALLTHROUGH */
 189                 case TNL:
 190                         if (tok == TNL) {
 191                                 parseheredoc();
 192                                 if (nlflag)
 193                                         return n1;
 194                         } else {
 195                                 tokpushback++;
 196                         }
 197                         checkkwd = 2;
 198                         if (tokendlist[peektoken()])
 199                                 return n1;
 200                         break;
 201                 case TEOF:
 202                         if (heredoclist)
 203                                 parseheredoc();
 204                         else
 205                                 pungetc();              /* push back EOF on input */
 206                         return n1;
 207                 default:
 208                         if (nlflag)
 209                                 synexpect(-1);
 210                         tokpushback++;
 211                         return n1;
 212                 }
 213         }
 214 }
 215
 216
 217
 218 STATIC union node *
 219 andor(void)
 220 {
 221         union node *n1, *n2, *n3;
 222         int t;
 223
 224         n1 = pipeline();
 225         for (;;) {
 226                 if ((t = readtoken()) == TAND) {
 227                         t = NAND;
 228                 } else if (t == TOR) {
 229                         t = NOR;
 230                 } else {
 231                         tokpushback++;
 232                         return n1;
 233                 }
 234                 n2 = pipeline();
 235                 n3 = (union node *)stalloc(sizeof (struct nbinary));
 236                 n3->type = t;
 237                 n3->nbinary.ch1 = n1;
 238                 n3->nbinary.ch2 = n2;
 239                 n1 = n3;
 240         }
 241 }
 242
 243
 244
 245 STATIC union node *
 246 pipeline(void)
 247 {
 248         union node *n1, *n2, *pipenode;
 249         struct nodelist *lp, *prev;
 250         int negate;
 251
 252         negate = 0;
 253         TRACE(("pipeline: entered\n"));
 254         while (readtoken() == TNOT)
 255                 negate = !negate;
 256         tokpushback++;
 257         n1 = command();
 258         if (readtoken() == TPIPE) {
 259                 pipenode = (union node *)stalloc(sizeof (struct npipe));
 260                 pipenode->type = NPIPE;
 261                 pipenode->npipe.backgnd = 0;
 262                 lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 263                 pipenode->npipe.cmdlist = lp;
 264                 lp->n = n1;
 265                 do {
 266                         prev = lp;
 267                         lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 268                         lp->n = command();
 269                         prev->next = lp;
 270                 } while (readtoken() == TPIPE);
 271                 lp->next = NULL;
 272                 n1 = pipenode;
 273         }
 274         tokpushback++;
 275         if (negate) {
 276                 n2 = (union node *)stalloc(sizeof (struct nnot));
 277                 n2->type = NNOT;
 278                 n2->nnot.com = n1;
 279                 return n2;
 280         } else
 281                 return n1;
 282 }
 283
 284
 285
 286 STATIC union node *
 287 command(void)
 288 {
 289         union node *n1, *n2;
 290         union node *ap, **app;
 291         union node *cp, **cpp;
 292         union node *redir, **rpp;
 293         int t, negate = 0;
 294
 295         checkkwd = 2;
 296         redir = NULL;
 297         n1 = NULL;
 298         rpp = &redir;
 299
 300         /* Check for redirection which may precede command */
 301         while (readtoken() == TREDIR) {
 302                 *rpp = n2 = redirnode;
 303                 rpp = &n2->nfile.next;
 304                 parsefname();
 305         }
 306         tokpushback++;
 307
 308         while (readtoken() == TNOT) {
 309                 TRACE(("command: TNOT recognized\n"));
 310                 negate = !negate;
 311         }
 312         tokpushback++;
 313
 314         switch (readtoken()) {
 315         case TIF:
 316                 n1 = (union node *)stalloc(sizeof (struct nif));
 317                 n1->type = NIF;
 318                 if ((n1->nif.test = list(0)) == NULL)
 319                         synexpect(-1);
 320                 if (readtoken() != TTHEN)
 321                         synexpect(TTHEN);
 322                 n1->nif.ifpart = list(0);
 323                 n2 = n1;
 324                 while (readtoken() == TELIF) {
 325                         n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
 326                         n2 = n2->nif.elsepart;
 327                         n2->type = NIF;
 328                         if ((n2->nif.test = list(0)) == NULL)
 329                                 synexpect(-1);
 330                         if (readtoken() != TTHEN)
 331                                 synexpect(TTHEN);
 332                         n2->nif.ifpart = list(0);
 333                 }
 334                 if (lasttoken == TELSE)
 335                         n2->nif.elsepart = list(0);
 336                 else {
 337                         n2->nif.elsepart = NULL;
 338                         tokpushback++;
 339                 }
 340                 if (readtoken() != TFI)
 341                         synexpect(TFI);
 342                 checkkwd = 1;
 343                 break;
 344         case TWHILE:
 345         case TUNTIL: {
 346                 int got;
 347                 n1 = (union node *)stalloc(sizeof (struct nbinary));
 348                 n1->type = (lasttoken == TWHILE)? NWHILE : NUNTIL;
 349                 if ((n1->nbinary.ch1 = list(0)) == NULL)
 350                         synexpect(-1);
 351                 if ((got=readtoken()) != TDO) {
 352 TRACE(("expecting DO got %s %s\n", tokname[got], got == TWORD ? wordtext : ""));
 353                         synexpect(TDO);
 354                 }
 355                 n1->nbinary.ch2 = list(0);
 356                 if (readtoken() != TDONE)
 357                         synexpect(TDONE);
 358                 checkkwd = 1;
 359                 break;
 360         }
 361         case TFOR:
 362                 if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
 363                         synerror("Bad for loop variable");
 364                 n1 = (union node *)stalloc(sizeof (struct nfor));
 365                 n1->type = NFOR;
 366                 n1->nfor.var = wordtext;
 367                 if (readtoken() == TWORD && ! quoteflag && equal(wordtext, "in")) {
 368                         app = &ap;
 369                         while (readtoken() == TWORD) {
 370                                 n2 = (union node *)stalloc(sizeof (struct narg));
 371                                 n2->type = NARG;
 372                                 n2->narg.text = wordtext;
 373                                 n2->narg.backquote = backquotelist;
 374                                 *app = n2;
 375                                 app = &n2->narg.next;
 376                         }
 377                         *app = NULL;
 378                         n1->nfor.args = ap;
 379                         if (lasttoken != TNL && lasttoken != TSEMI)
 380                                 synexpect(-1);
 381                 } else {
 382                         static char argvars[5] = {
 383                                 CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'
 384                         };
 385                         n2 = (union node *)stalloc(sizeof (struct narg));
 386                         n2->type = NARG;
 387                         n2->narg.text = argvars;
 388                         n2->narg.backquote = NULL;
 389                         n2->narg.next = NULL;
 390                         n1->nfor.args = n2;
 391                         /*
 392                          * Newline or semicolon here is optional (but note
 393                          * that the original Bourne shell only allowed NL).
 394                          */
 395                         if (lasttoken != TNL && lasttoken != TSEMI)
 396                                 tokpushback++;
 397                 }
 398                 checkkwd = 2;
 399                 if ((t = readtoken()) == TDO)
 400                         t = TDONE;
 401                 else if (t == TBEGIN)
 402                         t = TEND;
 403                 else
 404                         synexpect(-1);
 405                 n1->nfor.body = list(0);
 406                 if (readtoken() != t)
 407                         synexpect(t);
 408                 checkkwd = 1;
 409                 break;
 410         case TCASE:
 411                 n1 = (union node *)stalloc(sizeof (struct ncase));
 412                 n1->type = NCASE;
 413                 if (readtoken() != TWORD)
 414                         synexpect(TWORD);
 415                 n1->ncase.expr = n2 = (union node *)stalloc(sizeof (struct narg));
 416                 n2->type = NARG;
 417                 n2->narg.text = wordtext;
 418                 n2->narg.backquote = backquotelist;
 419                 n2->narg.next = NULL;
 420                 while (readtoken() == TNL);
 421                 if (lasttoken != TWORD || ! equal(wordtext, "in"))
 422                         synerror("expecting \"in\"");
 423                 cpp = &n1->ncase.cases;
 424                 noaliases = 1;  /* turn off alias expansion */
 425                 checkkwd = 2, readtoken();
 426                 while (lasttoken != TESAC) {
 427                         *cpp = cp = (union node *)stalloc(sizeof (struct nclist));
 428                         cp->type = NCLIST;
 429                         app = &cp->nclist.pattern;
 430                         if (lasttoken == TLP)
 431                                 readtoken();
 432                         for (;;) {
 433                                 *app = ap = (union node *)stalloc(sizeof (struct narg));
 434                                 ap->type = NARG;
 435                                 ap->narg.text = wordtext;
 436                                 ap->narg.backquote = backquotelist;
 437                                 if (checkkwd = 2, readtoken() != TPIPE)
 438                                         break;
 439                                 app = &ap->narg.next;
 440                                 readtoken();
 441                         }
 442                         ap->narg.next = NULL;
 443                         if (lasttoken != TRP)
 444                                 noaliases = 0, synexpect(TRP);
 445                         cp->nclist.body = list(0);
 446
 447                         checkkwd = 2;
 448                         if ((t = readtoken()) != TESAC) {
 449                                 if (t != TENDCASE)
 450                                         noaliases = 0, synexpect(TENDCASE);
 451                                 else
 452                                         checkkwd = 2, readtoken();
 453                         }
 454                         cpp = &cp->nclist.next;
 455                 }
 456                 noaliases = 0;  /* reset alias expansion */
 457                 *cpp = NULL;
 458                 checkkwd = 1;
 459                 break;
 460         case TLP:
 461                 n1 = (union node *)stalloc(sizeof (struct nredir));
 462                 n1->type = NSUBSHELL;
 463                 n1->nredir.n = list(0);
 464                 n1->nredir.redirect = NULL;
 465                 if (readtoken() != TRP)
 466                         synexpect(TRP);
 467                 checkkwd = 1;
 468                 break;
 469         case TBEGIN:
 470                 n1 = list(0);
 471                 if (readtoken() != TEND)
 472                         synexpect(TEND);
 473                 checkkwd = 1;
 474                 break;
 475         /* Handle an empty command like other simple commands.  */
 476         case TSEMI:
 477         case TAND:
 478         case TOR:
 479                 /*
 480                  * An empty command before a ; doesn't make much sense, and
 481                  * should certainly be disallowed in the case of `if ;'.
 482                  */
 483                 if (!redir)
 484                         synexpect(-1);
 485         case TNL:
 486         case TEOF:
 487         case TWORD:
 488         case TRP:
 489                 tokpushback++;
 490                 n1 = simplecmd(rpp, redir);
 491                 goto checkneg;
 492         default:
 493                 synexpect(-1);
 494         }
 495
 496         /* Now check for redirection which may follow command */
 497         while (readtoken() == TREDIR) {
 498                 *rpp = n2 = redirnode;
 499                 rpp = &n2->nfile.next;
 500                 parsefname();
 501         }
 502         tokpushback++;
 503         *rpp = NULL;
 504         if (redir) {
 505                 if (n1->type != NSUBSHELL) {
 506                         n2 = (union node *)stalloc(sizeof (struct nredir));
 507                         n2->type = NREDIR;
 508                         n2->nredir.n = n1;
 509                         n1 = n2;
 510                 }
 511                 n1->nredir.redirect = redir;
 512         }
 513
 514 checkneg:
 515         if (negate) {
 516                 n2 = (union node *)stalloc(sizeof (struct nnot));
 517                 n2->type = NNOT;
 518                 n2->nnot.com = n1;
 519                 return n2;
 520         }
 521         else
 522                 return n1;
 523 }
 524
 525
 526 STATIC union node *
 527 simplecmd(union node **rpp, union node *redir)
 528 {
 529         union node *args, **app;
 530         union node **orig_rpp = rpp;
 531         union node *n = NULL, *n2;
 532         int negate = 0;
 533
 534         /* If we don't have any redirections already, then we must reset */
 535         /* rpp to be the address of the local redir variable.  */
 536         if (redir == 0)
 537                 rpp = &redir;
 538
 539         args = NULL;
 540         app = &args;
 541         /*
 542          * We save the incoming value, because we need this for shell
 543          * functions.  There can not be a redirect or an argument between
 544          * the function name and the open parenthesis.
 545          */
 546         orig_rpp = rpp;
 547
 548         while (readtoken() == TNOT) {
 549                 TRACE(("command: TNOT recognized\n"));
 550                 negate = !negate;
 551         }
 552         tokpushback++;
 553
 554         for (;;) {
 555                 if (readtoken() == TWORD) {
 556                         n = (union node *)stalloc(sizeof (struct narg));
 557                         n->type = NARG;
 558                         n->narg.text = wordtext;
 559                         n->narg.backquote = backquotelist;
 560                         *app = n;
 561                         app = &n->narg.next;
 562                 } else if (lasttoken == TREDIR) {
 563                         *rpp = n = redirnode;
 564                         rpp = &n->nfile.next;
 565                         parsefname();   /* read name of redirection file */
 566                 } else if (lasttoken == TLP && app == &args->narg.next
 567                                             && rpp == orig_rpp) {
 568                         /* We have a function */
 569                         if (readtoken() != TRP)
 570                                 synexpect(TRP);
 571                         funclinno = plinno;
 572 #ifdef notdef
 573                         if (! goodname(n->narg.text))
 574                                 synerror("Bad function name");
 575 #endif
 576                         n->type = NDEFUN;
 577                         n->narg.next = command();
 578                         funclinno = 0;
 579                         goto checkneg;
 580                 } else {
 581                         tokpushback++;
 582                         break;
 583                 }
 584         }
 585         *app = NULL;
 586         *rpp = NULL;
 587         n = (union node *)stalloc(sizeof (struct ncmd));
 588         n->type = NCMD;
 589         n->ncmd.backgnd = 0;
 590         n->ncmd.args = args;
 591         n->ncmd.redirect = redir;
 592
 593 checkneg:
 594         if (negate) {
 595                 n2 = (union node *)stalloc(sizeof (struct nnot));
 596                 n2->type = NNOT;
 597                 n2->nnot.com = n;
 598                 return n2;
 599         }
 600         else
 601                 return n;
 602 }
 603
 604 STATIC union node *
 605 makename(void)
 606 {
 607         union node *n;
 608
 609         n = (union node *)stalloc(sizeof (struct narg));
 610         n->type = NARG;
 611         n->narg.next = NULL;
 612         n->narg.text = wordtext;
 613         n->narg.backquote = backquotelist;
 614         return n;
 615 }
 616
 617 void fixredir(union node *n, const char *text, int err)
 618 {
 619         TRACE(("Fix redir %s %d\n", text, err));
 620         if (!err)
 621                 n->ndup.vname = NULL;
 622
 623         if (is_digit(text[0]) && text[1] == '\0')
 624                 n->ndup.dupfd = digit_val(text[0]);
 625         else if (text[0] == '-' && text[1] == '\0')
 626                 n->ndup.dupfd = -1;
 627         else {
 628
 629                 if (err)
 630                         synerror("Bad fd number");
 631                 else
 632                         n->ndup.vname = makename();
 633         }
 634 }
 635
 636
 637 STATIC void
 638 parsefname(void)
 639 {
 640         union node *n = redirnode;
 641
 642         if (readtoken() != TWORD)
 643                 synexpect(-1);
 644         if (n->type == NHERE) {
 645                 struct heredoc *here = heredoc;
 646                 struct heredoc *p;
 647                 int i;
 648
 649                 if (quoteflag == 0)
 650                         n->type = NXHERE;
 651                 TRACE(("Here document %d\n", n->type));
 652                 if (here->striptabs) {
 653                         while (*wordtext == '\t')
 654                                 wordtext++;
 655                 }
 656                 if (! noexpand(wordtext) || (i = strlen(wordtext)) == 0 || i > EOFMARKLEN)
 657                         synerror("Illegal eof marker for << redirection");
 658                 rmescapes(wordtext);
 659                 here->eofmark = wordtext;
 660                 here->next = NULL;
 661                 if (heredoclist == NULL)
 662                         heredoclist = here;
 663                 else {
 664                         for (p = heredoclist ; p->next ; p = p->next);
 665                         p->next = here;
 666                 }
 667         } else if (n->type == NTOFD || n->type == NFROMFD) {
 668                 fixredir(n, wordtext, 0);
 669         } else {
 670                 n->nfile.fname = makename();
 671         }
 672 }
 673
 674
 675 /*
 676  * Input any here documents.
 677  */
 678
 679 STATIC void
 680 parseheredoc(void)
 681 {
 682         struct heredoc *here;
 683         union node *n;
 684
 685         while (heredoclist) {
 686                 here = heredoclist;
 687                 heredoclist = here->next;
 688                 if (needprompt) {
 689                         setprompt(2);
 690                         needprompt = 0;
 691                 }
 692                 readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
 693                                 here->eofmark, here->striptabs);
 694                 n = (union node *)stalloc(sizeof (struct narg));
 695                 n->narg.type = NARG;
 696                 n->narg.next = NULL;
 697                 n->narg.text = wordtext;
 698                 n->narg.backquote = backquotelist;
 699                 here->here->nhere.doc = n;
 700         }
 701 }
 702
 703 STATIC int
 704 peektoken(void)
 705 {
 706         int t;
 707
 708         t = readtoken();
 709         tokpushback++;
 710         return (t);
 711 }
 712
 713 STATIC int
 714 readtoken(void)
 715 {
 716         int t;
 717         int savecheckkwd = checkkwd;
 718         struct alias *ap;
 719 #ifdef DEBUG
 720         int alreadyseen = tokpushback;
 721 #endif
 722
 723         top:
 724         t = xxreadtoken();
 725
 726         if (checkkwd) {
 727                 /*
 728                  * eat newlines
 729                  */
 730                 if (checkkwd == 2) {
 731                         checkkwd = 0;
 732                         while (t == TNL) {
 733                                 parseheredoc();
 734                                 t = xxreadtoken();
 735                         }
 736                 } else
 737                         checkkwd = 0;
 738                 /*
 739                  * check for keywords and aliases
 740                  */
 741                 if (t == TWORD && !quoteflag)
 742                 {
 743                         const char * const *pp;
 744
 745                         for (pp = parsekwd; *pp; pp++) {
 746                                 if (**pp == *wordtext && equal(*pp, wordtext))
 747                                 {
 748                                         lasttoken = t = pp - parsekwd + KWDOFFSET;
 749                                         TRACE(("keyword %s recognized\n", tokname[t]));
 750                                         goto out;
 751                                 }
 752                         }
 753                         if (noaliases == 0 &&
 754                             (ap = lookupalias(wordtext, 1)) != NULL) {
 755                                 pushstring(ap->val, strlen(ap->val), ap);
 756                                 checkkwd = savecheckkwd;
 757                                 goto top;
 758                         }
 759                 }
 760 out:
 761                 checkkwd = (t == TNOT) ? savecheckkwd : 0;
 762         }
 763 #ifdef DEBUG
 764         if (!alreadyseen)
 765             TRACE(("token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 766         else
 767             TRACE(("reread token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 768 #endif
 769         return (t);
 770 }
 771
 772
 773 /*
 774  * Read the next input token.
 775  * If the token is a word, we set backquotelist to the list of cmds in
 776  *      backquotes.  We set quoteflag to true if any part of the word was
 777  *      quoted.
 778  * If the token is TREDIR, then we set redirnode to a structure containing
 779  *      the redirection.
 780  * In all cases, the variable startlinno is set to the number of the line
 781  *      on which the token starts.
 782  *
 783  * [Change comment:  here documents and internal procedures]
 784  * [Readtoken shouldn't have any arguments.  Perhaps we should make the
 785  *  word parsing code into a separate routine.  In this case, readtoken
 786  *  doesn't need to have any internal procedures, but parseword does.
 787  *  We could also make parseoperator in essence the main routine, and
 788  *  have parseword (readtoken1?) handle both words and redirection.]
 789  */
 790
 791 #define RETURN(token)   return lasttoken = token
 792
 793 STATIC int
 794 xxreadtoken(void)
 795 {
 796         int c;
 797
 798         if (tokpushback) {
 799                 tokpushback = 0;
 800                 return lasttoken;
 801         }
 802         if (needprompt) {
 803                 setprompt(2);
 804                 needprompt = 0;
 805         }
 806         startlinno = plinno;
 807         for (;;) {      /* until token or start of word found */
 808                 c = pgetc_macro();
 809                 if (c == ' ' || c == '\t')
 810                         continue;               /* quick check for white space first */
 811                 switch (c) {
 812                 case ' ': case '\t':
 813                         continue;
 814                 case '#':
 815                         while ((c = pgetc()) != '\n' && c != PEOF);
 816                         pungetc();
 817                         continue;
 818                 case '\\':
 819                         if (pgetc() == '\n') {
 820                                 startlinno = ++plinno;
 821                                 if (doprompt)
 822                                         setprompt(2);
 823                                 else
 824                                         setprompt(0);
 825                                 continue;
 826                         }
 827                         pungetc();
 828                         goto breakloop;
 829                 case '\n':
 830                         plinno++;
 831                         needprompt = doprompt;
 832                         RETURN(TNL);
 833                 case PEOF:
 834                         RETURN(TEOF);
 835                 case '&':
 836                         if (pgetc() == '&')
 837                                 RETURN(TAND);
 838                         pungetc();
 839                         RETURN(TBACKGND);
 840                 case '|':
 841                         if (pgetc() == '|')
 842                                 RETURN(TOR);
 843                         pungetc();
 844                         RETURN(TPIPE);
 845                 case ';':
 846                         if (pgetc() == ';')
 847                                 RETURN(TENDCASE);
 848                         pungetc();
 849                         RETURN(TSEMI);
 850                 case '(':
 851                         RETURN(TLP);
 852                 case ')':
 853                         RETURN(TRP);
 854                 default:
 855                         goto breakloop;
 856                 }
 857         }
 858 breakloop:
 859         return readtoken1(c, BASESYNTAX, (char *)NULL, 0);
 860 #undef RETURN
 861 }
 862
 863
 864
 865 /*
 866  * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
 867  * is not NULL, read a here document.  In the latter case, eofmark is the
 868  * word which marks the end of the document and striptabs is true if
 869  * leading tabs should be stripped from the document.  The argument firstc
 870  * is the first character of the input token or document.
 871  *
 872  * Because C does not have internal subroutines, I have simulated them
 873  * using goto's to implement the subroutine linkage.  The following macros
 874  * will run code that appears at the end of readtoken1.
 875  */
 876
 877 #define CHECKEND()      {goto checkend; checkend_return:;}
 878 #define PARSEREDIR()    {goto parseredir; parseredir_return:;}
 879 #define PARSESUB()      {goto parsesub; parsesub_return:;}
 880 #define PARSEBACKQOLD() {oldstyle = 1; goto parsebackq; parsebackq_oldreturn:;}
 881 #define PARSEBACKQNEW() {oldstyle = 0; goto parsebackq; parsebackq_newreturn:;}
 882 #define PARSEARITH()    {goto parsearith; parsearith_return:;}
 883
 884 STATIC int
 885 readtoken1(int firstc, char const *syntax, char *eofmark, int striptabs)
 886 {
 887         int c = firstc;
 888         char *out;
 889         int len;
 890         char line[EOFMARKLEN + 1];
 891         struct nodelist *bqlist;
 892         int quotef;
 893         int dblquote;
 894         int varnest;    /* levels of variables expansion */
 895         int arinest;    /* levels of arithmetic expansion */
 896         int parenlevel; /* levels of parens in arithmetic */
 897         int oldstyle;
 898         char const *prevsyntax; /* syntax before arithmetic */
 899         int synentry;
 900 #if __GNUC__
 901         /* Avoid longjmp clobbering */
 902         (void) &out;
 903         (void) &quotef;
 904         (void) &dblquote;
 905         (void) &varnest;
 906         (void) &arinest;
 907         (void) &parenlevel;
 908         (void) &oldstyle;
 909         (void) &prevsyntax;
 910         (void) &syntax;
 911         (void) &synentry;
 912 #endif
 913
 914         startlinno = plinno;
 915         dblquote = 0;
 916         if (syntax == DQSYNTAX)
 917                 dblquote = 1;
 918         quotef = 0;
 919         bqlist = NULL;
 920         varnest = 0;
 921         arinest = 0;
 922         parenlevel = 0;
 923
 924         STARTSTACKSTR(out);
 925         loop: { /* for each line, until end of word */
 926                 CHECKEND();     /* set c to PEOF if at end of here document */
 927                 for (;;) {      /* until end of line or end of word */
 928                         CHECKSTRSPACE(3, out);  /* permit 3 calls to USTPUTC */
 929
 930                         synentry = syntax[c];
 931
 932                         switch(synentry) {
 933                         case CNL:       /* '\n' */
 934                                 if (syntax == BASESYNTAX)
 935                                         goto endword;   /* exit outer loop */
 936                                 USTPUTC(c, out);
 937                                 plinno++;
 938                                 if (doprompt)
 939                                         setprompt(2);
 940                                 else
 941                                         setprompt(0);
 942                                 c = pgetc();
 943                                 goto loop;              /* continue outer loop */
 944                         case CWORD:
 945                                 USTPUTC(c, out);
 946                                 break;
 947                         case CCTL:
 948                                 if (eofmark == NULL || dblquote)
 949                                         USTPUTC(CTLESC, out);
 950                                 USTPUTC(c, out);
 951                                 break;
 952                         case CBACK:     /* backslash */
 953                                 c = pgetc();
 954                                 if (c == PEOF) {
 955                                         USTPUTC('\\', out);
 956                                         pungetc();
 957                                 } else if (c == '\n') {
 958                                         plinno++;
 959                                         if (doprompt)
 960                                                 setprompt(2);
 961                                         else
 962                                                 setprompt(0);
 963                                 } else {
 964                                         if (dblquote && c != '\\' &&
 965                                             c != '`' && c != '$' &&
 966                                             (c != '"' || eofmark != NULL))
 967                                                 USTPUTC('\\', out);
 968                                         if (SQSYNTAX[c] == CCTL)
 969                                                 USTPUTC(CTLESC, out);
 970                                         else if (eofmark == NULL)
 971                                                 USTPUTC(CTLQUOTEMARK, out);
 972                                         USTPUTC(c, out);
 973                                         quotef++;
 974                                 }
 975                                 break;
 976                         case CSQUOTE:
 977                                 if (eofmark == NULL)
 978                                         USTPUTC(CTLQUOTEMARK, out);
 979                                 syntax = SQSYNTAX;
 980                                 break;
 981                         case CDQUOTE:
 982                                 if (eofmark == NULL)
 983                                         USTPUTC(CTLQUOTEMARK, out);
 984                                 syntax = DQSYNTAX;
 985                                 dblquote = 1;
 986                                 break;
 987                         case CENDQUOTE:
 988                                 if (eofmark != NULL && arinest == 0 &&
 989                                     varnest == 0) {
 990                                         USTPUTC(c, out);
 991                                 } else {
 992                                         if (arinest) {
 993                                                 syntax = ARISYNTAX;
 994                                                 dblquote = 0;
 995                                         } else if (eofmark == NULL) {
 996                                                 syntax = BASESYNTAX;
 997                                                 dblquote = 0;
 998                                         }
 999                                         quotef++;
1000                                 }
1001                                 break;
1002                         case CVAR:      /* '$' */
1003                                 PARSESUB();             /* parse substitution */
1004                                 break;
1005                         case CENDVAR:   /* '}' */
1006                                 if (varnest > 0) {
1007                                         varnest--;
1008                                         USTPUTC(CTLENDVAR, out);
1009                                 } else {
1010                                         USTPUTC(c, out);
1011                                 }
1012                                 break;
1013                         case CLP:       /* '(' in arithmetic */
1014                                 parenlevel++;
1015                                 USTPUTC(c, out);
1016                                 break;
1017                         case CRP:       /* ')' in arithmetic */
1018                                 if (parenlevel > 0) {
1019                                         USTPUTC(c, out);
1020                                         --parenlevel;
1021                                 } else {
1022                                         if (pgetc() == ')') {
1023                                                 if (--arinest == 0) {
1024                                                         USTPUTC(CTLENDARI, out);
1025                                                         syntax = prevsyntax;
1026                                                         if (syntax == DQSYNTAX)
1027                                                                 dblquote = 1;
1028                                                         else
1029                                                                 dblquote = 0;
1030                                                 } else
1031                                                         USTPUTC(')', out);
1032                                         } else {
1033                                                 /*
1034                                                  * unbalanced parens
1035                                                  *  (don't 2nd guess - no error)
1036                                                  */
1037                                                 pungetc();
1038                                                 USTPUTC(')', out);
1039                                         }
1040                                 }
1041                                 break;
1042                         case CBQUOTE:   /* '`' */
1043                                 PARSEBACKQOLD();
1044                                 break;
1045                         case CEOF:
1046                                 goto endword;           /* exit outer loop */
1047                         default:
1048                                 if (varnest == 0)
1049                                         goto endword;   /* exit outer loop */
1050                                 USTPUTC(c, out);
1051                         }
1052                         c = pgetc_macro();
1053                 }
1054         }
1055 endword:
1056         if (syntax == ARISYNTAX)
1057                 synerror("Missing '))'");
1058         if (syntax != BASESYNTAX && ! parsebackquote && eofmark == NULL)
1059                 synerror("Unterminated quoted string");
1060         if (varnest != 0) {
1061                 startlinno = plinno;
1062                 synerror("Missing '}'");
1063         }
1064         USTPUTC('\0', out);
1065         len = out - stackblock();
1066         out = stackblock();
1067         if (eofmark == NULL) {
1068                 if ((c == '>' || c == '<')
1069                  && quotef == 0
1070                  && len <= 2
1071                  && (*out == '\0' || is_digit(*out))) {
1072                         PARSEREDIR();
1073                         return lasttoken = TREDIR;
1074                 } else {
1075                         pungetc();
1076                 }
1077         }
1078         quoteflag = quotef;
1079         backquotelist = bqlist;
1080         grabstackblock(len);
1081         wordtext = out;
1082         return lasttoken = TWORD;
1083 /* end of readtoken routine */
1084
1085
1086
1087 /*
1088  * Check to see whether we are at the end of the here document.  When this
1089  * is called, c is set to the first character of the next input line.  If
1090  * we are at the end of the here document, this routine sets the c to PEOF.
1091  */
1092
1093 checkend: {
1094         if (eofmark) {
1095                 if (striptabs) {
1096                         while (c == '\t')
1097                                 c = pgetc();
1098                 }
1099                 if (c == *eofmark) {
1100                         if (pfgets(line, sizeof line) != NULL) {
1101                                 char *p, *q;
1102
1103                                 p = line;
1104                                 for (q = eofmark + 1 ; *q && *p == *q ; p++, q++);
1105                                 if (*p == '\n' && *q == '\0') {
1106                                         c = PEOF;
1107                                         plinno++;
1108                                         needprompt = doprompt;
1109                                 } else {
1110                                         pushstring(line, strlen(line), NULL);
1111                                 }
1112                         }
1113                 }
1114         }
1115         goto checkend_return;
1116 }
1117
1118
1119 /*
1120  * Parse a redirection operator.  The variable "out" points to a string
1121  * specifying the fd to be redirected.  The variable "c" contains the
1122  * first character of the redirection operator.
1123  */
1124
1125 parseredir: {
1126         char fd = *out;
1127         union node *np;
1128
1129         np = (union node *)stalloc(sizeof (struct nfile));
1130         if (c == '>') {
1131                 np->nfile.fd = 1;
1132                 c = pgetc();
1133                 if (c == '>')
1134                         np->type = NAPPEND;
1135                 else if (c == '&')
1136                         np->type = NTOFD;
1137                 else if (c == '|')
1138                         np->type = NCLOBBER;
1139                 else {
1140                         np->type = NTO;
1141                         pungetc();
1142                 }
1143         } else {        /* c == '<' */
1144                 np->nfile.fd = 0;
1145                 c = pgetc();
1146                 if (c == '<') {
1147                         if (sizeof (struct nfile) != sizeof (struct nhere)) {
1148                                 np = (union node *)stalloc(sizeof (struct nhere));
1149                                 np->nfile.fd = 0;
1150                         }
1151                         np->type = NHERE;
1152                         heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
1153                         heredoc->here = np;
1154                         if ((c = pgetc()) == '-') {
1155                                 heredoc->striptabs = 1;
1156                         } else {
1157                                 heredoc->striptabs = 0;
1158                                 pungetc();
1159                         }
1160                 } else if (c == '&')
1161                         np->type = NFROMFD;
1162                 else if (c == '>')
1163                         np->type = NFROMTO;
1164                 else {
1165                         np->type = NFROM;
1166                         pungetc();
1167                 }
1168         }
1169         if (fd != '\0')
1170                 np->nfile.fd = digit_val(fd);
1171         redirnode = np;
1172         goto parseredir_return;
1173 }
1174
1175
1176 /*
1177  * Parse a substitution.  At this point, we have read the dollar sign
1178  * and nothing else.
1179  */
1180
1181 parsesub: {
1182         char buf[10];
1183         int subtype;
1184         int typeloc;
1185         int flags;
1186         char *p;
1187         static const char types[] = "}-+?=";
1188         int bracketed_name = 0; /* used to handle ${[0-9]*} variables */
1189         int i;
1190         int linno;
1191         int length;
1192
1193         c = pgetc();
1194         if (c != '(' && c != '{' && (is_eof(c) || !is_name(c)) &&
1195             !is_special(c)) {
1196                 USTPUTC('$', out);
1197                 pungetc();
1198         } else if (c == '(') {  /* $(command) or $((arith)) */
1199                 if (pgetc() == '(') {
1200                         PARSEARITH();
1201                 } else {
1202                         pungetc();
1203                         PARSEBACKQNEW();
1204                 }
1205         } else {
1206                 USTPUTC(CTLVAR, out);
1207                 typeloc = out - stackblock();
1208                 USTPUTC(VSNORMAL, out);
1209                 subtype = VSNORMAL;
1210                 flags = 0;
1211                 if (c == '{') {
1212                         bracketed_name = 1;
1213                         c = pgetc();
1214                         if (c == '#') {
1215                                 if ((c = pgetc()) == '}')
1216                                         c = '#';
1217                                 else
1218                                         subtype = VSLENGTH;
1219                         }
1220                         else
1221                                 subtype = 0;
1222                 }
1223                 if (!is_eof(c) && is_name(c)) {
1224                         length = 0;
1225                         do {
1226                                 STPUTC(c, out);
1227                                 c = pgetc();
1228                                 length++;
1229                         } while (!is_eof(c) && is_in_name(c));
1230                         if (length == 6 &&
1231                             strncmp(out - length, "LINENO", length) == 0) {
1232                                 /* Replace the variable name with the
1233                                  * current line number. */
1234                                 linno = plinno;
1235                                 if (funclinno != 0)
1236                                         linno -= funclinno - 1;
1237                                 snprintf(buf, sizeof(buf), "%d", linno);
1238                                 STADJUST(-6, out);
1239                                 for (i = 0; buf[i] != '\0'; i++)
1240                                         STPUTC(buf[i], out);
1241                                 flags |= VSLINENO;
1242                         }
1243                 } else if (is_digit(c)) {
1244                         if (bracketed_name) {
1245                                 do {
1246                                         STPUTC(c, out);
1247                                         c = pgetc();
1248                                 } while (is_digit(c));
1249                         } else {
1250                                 STPUTC(c, out);
1251                                 c = pgetc();
1252                         }
1253                 } else {
1254                         if (! is_special(c)) {
1255                                 subtype = VSERROR;
1256                                 if (c == '}')
1257                                         pungetc();
1258                                 else
1259                                         USTPUTC(c, out);
1260                         } else {
1261                                 USTPUTC(c, out);
1262                                 c = pgetc();
1263                         }
1264                 }
1265                 if (subtype == 0) {
1266                         switch (c) {
1267                         case ':':
1268                                 flags |= VSNUL;
1269                                 c = pgetc();
1270                                 /*FALLTHROUGH*/
1271                         default:
1272                                 p = strchr(types, c);
1273                                 if (p == NULL) {
1274                                         if (flags == VSNUL)
1275                                                 STPUTC(':', out);
1276                                         STPUTC(c, out);
1277                                         subtype = VSERROR;
1278                                 } else
1279                                         subtype = p - types + VSNORMAL;
1280                                 break;
1281                         case '%':
1282                         case '#':
1283                                 {
1284                                         int cc = c;
1285                                         subtype = c == '#' ? VSTRIMLEFT :
1286                                                              VSTRIMRIGHT;
1287                                         c = pgetc();
1288                                         if (c == cc)
1289                                                 subtype++;
1290                                         else
1291                                                 pungetc();
1292                                         break;
1293                                 }
1294                         }
1295                 } else if (subtype != VSERROR) {
1296                         pungetc();
1297                 }
1298                 STPUTC('=', out);
1299                 if (subtype != VSLENGTH && (dblquote || arinest))
1300                         flags |= VSQUOTE;
1301                 *(stackblock() + typeloc) = subtype | flags;
1302                 if (subtype != VSNORMAL)
1303                         varnest++;
1304         }
1305         goto parsesub_return;
1306 }
1307
1308
1309 /*
1310  * Called to parse command substitutions.  Newstyle is set if the command
1311  * is enclosed inside $(...); nlpp is a pointer to the head of the linked
1312  * list of commands (passed by reference), and savelen is the number of
1313  * characters on the top of the stack which must be preserved.
1314  */
1315
1316 parsebackq: {
1317         struct nodelist **nlpp;
1318         int savepbq;
1319         union node *n;
1320         char *volatile str;
1321         struct jmploc jmploc;
1322         struct jmploc *volatile savehandler;
1323         int savelen;
1324         int saveprompt;
1325 #if __GNUC__
1326         /* Avoid longjmp clobbering */
1327         (void) &saveprompt;
1328 #endif
1329
1330         savepbq = parsebackquote;
1331         if (setjmp(jmploc.loc)) {
1332                 if (str)
1333                         ckfree(str);
1334                 parsebackquote = 0;
1335                 handler = savehandler;
1336                 longjmp(handler->loc, 1);
1337         }
1338         INTOFF;
1339         str = NULL;
1340         savelen = out - stackblock();
1341         if (savelen > 0) {
1342                 str = ckmalloc(savelen);
1343                 memcpy(str, stackblock(), savelen);
1344         }
1345         savehandler = handler;
1346         handler = &jmploc;
1347         INTON;
1348         if (oldstyle) {
1349                 /* We must read until the closing backquote, giving special
1350                    treatment to some slashes, and then push the string and
1351                    reread it as input, interpreting it normally.  */
1352                 char *out;
1353                 int c;
1354                 int savelen;
1355                 char *str;
1356
1357
1358                 STARTSTACKSTR(out);
1359                 for (;;) {
1360                         if (needprompt) {
1361                                 setprompt(2);
1362                                 needprompt = 0;
1363                         }
1364                         switch (c = pgetc()) {
1365                         case '`':
1366                                 goto done;
1367
1368                         case '\\':
1369                                 if ((c = pgetc()) == '\n') {
1370                                         plinno++;
1371                                         if (doprompt)
1372                                                 setprompt(2);
1373                                         else
1374                                                 setprompt(0);
1375                                         /*
1376                                          * If eating a newline, avoid putting
1377                                          * the newline into the new character
1378                                          * stream (via the STPUTC after the
1379                                          * switch).
1380                                          */
1381                                         continue;
1382                                 }
1383                                 if (c != '\\' && c != '`' && c != '$'
1384                                     && (!dblquote || c != '"'))
1385                                         STPUTC('\\', out);
1386                                 break;
1387
1388                         case '\n':
1389                                 plinno++;
1390                                 needprompt = doprompt;
1391                                 break;
1392
1393                         case PEOF:
1394                                 startlinno = plinno;
1395                                 synerror("EOF in backquote substitution");
1396                                 break;
1397
1398                         default:
1399                                 break;
1400                         }
1401                         STPUTC(c, out);
1402                 }
1403 done:
1404                 STPUTC('\0', out);
1405                 savelen = out - stackblock();
1406                 if (savelen > 0) {
1407                         str = ckmalloc(savelen);
1408                         memcpy(str, stackblock(), savelen);
1409                         setinputstring(str, 1);
1410                 }
1411         }
1412         nlpp = &bqlist;
1413         while (*nlpp)
1414                 nlpp = &(*nlpp)->next;
1415         *nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
1416         (*nlpp)->next = NULL;
1417         parsebackquote = oldstyle;
1418
1419         if (oldstyle) {
1420                 saveprompt = doprompt;
1421                 doprompt = 0;
1422         }
1423
1424         n = list(0);
1425
1426         if (oldstyle)
1427                 doprompt = saveprompt;
1428         else {
1429                 if (readtoken() != TRP)
1430                         synexpect(TRP);
1431         }
1432
1433         (*nlpp)->n = n;
1434         if (oldstyle) {
1435                 /*
1436                  * Start reading from old file again, ignoring any pushed back
1437                  * tokens left from the backquote parsing
1438                  */
1439                 popfile();
1440                 tokpushback = 0;
1441         }
1442         while (stackblocksize() <= savelen)
1443                 growstackblock();
1444         STARTSTACKSTR(out);
1445         if (str) {
1446                 memcpy(out, str, savelen);
1447                 STADJUST(savelen, out);
1448                 INTOFF;
1449                 ckfree(str);
1450                 str = NULL;
1451                 INTON;
1452         }
1453         parsebackquote = savepbq;
1454         handler = savehandler;
1455         if (arinest || dblquote)
1456                 USTPUTC(CTLBACKQ | CTLQUOTE, out);
1457         else
1458                 USTPUTC(CTLBACKQ, out);
1459         if (oldstyle)
1460                 goto parsebackq_oldreturn;
1461         else
1462                 goto parsebackq_newreturn;
1463 }
1464
1465 /*
1466  * Parse an arithmetic expansion (indicate start of one and set state)
1467  */
1468 parsearith: {
1469
1470         if (++arinest == 1) {
1471                 prevsyntax = syntax;
1472                 syntax = ARISYNTAX;
1473                 USTPUTC(CTLARI, out);
1474                 if (dblquote)
1475                         USTPUTC('"',out);
1476                 else
1477                         USTPUTC(' ',out);
1478         } else {
1479                 /*
1480                  * we collapse embedded arithmetic expansion to
1481                  * parenthesis, which should be equivalent
1482                  */
1483                 USTPUTC('(', out);
1484         }
1485         goto parsearith_return;
1486 }
1487
1488 } /* end of readtoken */
1489
1490
1491
1492 #ifdef mkinit
1493 RESET {
1494         tokpushback = 0;
1495         checkkwd = 0;
1496 }
1497 #endif
1498
1499 /*
1500  * Returns true if the text contains nothing to expand (no dollar signs
1501  * or backquotes).
1502  */
1503
1504 STATIC int
1505 noexpand(char *text)
1506 {
1507         char *p;
1508         char c;
1509
1510         p = text;
1511         while ((c = *p++) != '\0') {
1512                 if ( c == CTLQUOTEMARK)
1513                         continue;
1514                 if (c == CTLESC)
1515                         p++;
1516                 else if (BASESYNTAX[(int)c] == CCTL)
1517                         return 0;
1518         }
1519         return 1;
1520 }
1521
1522
1523 /*
1524  * Return true if the argument is a legal variable name (a letter or
1525  * underscore followed by zero or more letters, underscores, and digits).
1526  */
1527
1528 int
1529 goodname(char *name)
1530 {
1531         char *p;
1532
1533         p = name;
1534         if (! is_name(*p))
1535                 return 0;
1536         while (*++p) {
1537                 if (! is_in_name(*p))
1538                         return 0;
1539         }
1540         return 1;
1541 }
1542
1543
1544 /*
1545  * Called when an unexpected token is read during the parse.  The argument
1546  * is the token that is expected, or -1 if more than one type of token can
1547  * occur at this point.
1548  */
1549
1550 STATIC void
1551 synexpect(int token)
1552 {
1553         char msg[64];
1554
1555         if (token >= 0) {
1556                 fmtstr(msg, 64, "%s unexpected (expecting %s)",
1557                         tokname[lasttoken], tokname[token]);
1558         } else {
1559                 fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
1560         }
1561         synerror(msg);
1562 }
1563
1564
1565 STATIC void
1566 synerror(char *msg)
1567 {
1568         if (commandname)
1569                 outfmt(&errout, "%s: %d: ", commandname, startlinno);
1570         outfmt(&errout, "Syntax error: %s\n", msg);
1571         error((char *)NULL);
1572 }
1573
1574 STATIC void
1575 setprompt(int which)
1576 {
1577         whichprompt = which;
1578
1579 #ifndef NO_HISTORY
1580         if (!el)
1581 #endif
1582                 out2str(getprompt(NULL));
1583 }
1584
1585 /*
1586  * called by editline -- any expansions to the prompt
1587  *    should be added here.
1588  */
1589 char *
1590 getprompt(void *unused __unused)
1591 {
1592         static char ps[PROMPTLEN];
1593         char *fmt;
1594         int i, j, trim;
1595
1596         /*
1597          * Select prompt format.
1598          */
1599         switch (whichprompt) {
1600         case 0:
1601                 fmt = "";
1602                 break;
1603         case 1:
1604                 fmt = ps1val();
1605                 break;
1606         case 2:
1607                 fmt = ps2val();
1608                 break;
1609         default:
1610                 return "<internal prompt error>";
1611         }
1612
1613         /*
1614          * Format prompt string.
1615          */
1616         for (i = 0; (i < 127) && (*fmt != '\0'); i++, fmt++)
1617                 if (*fmt == '\\')
1618                         switch (*++fmt) {
1619
1620                                 /*
1621                                  * Hostname.
1622                                  *
1623                                  * \h specifies just the local hostname,
1624                                  * \H specifies fully-qualified hostname.
1625                                  */
1626                         case 'h':
1627                         case 'H':
1628                                 ps[i] = '\0';
1629                                 gethostname(&ps[i], PROMPTLEN - i);
1630                                 /* Skip to end of hostname. */
1631                                 trim = (*fmt == 'h') ? '.' : '\0';
1632                                 while ((ps[i+1] != '\0') && (ps[i+1] != trim))
1633                                         i++;
1634                                 break;
1635
1636                                 /*
1637                                  * Working directory.
1638                                  *
1639                                  * \W specifies just the final component,
1640                                  * \w specifies the entire path.
1641                                  */
1642                         case 'W':
1643                         case 'w':
1644                                 ps[i] = '\0';
1645                                 getcwd(&ps[i], PROMPTLEN - i);
1646                                 if (*fmt == 'W') {
1647                                         /* Final path component only. */
1648                                         trim = 1;
1649                                         for (j = i; ps[j] != '\0'; j++)
1650                                           if (ps[j] == '/')
1651                                                 trim = j + 1;
1652                                         memmove(&ps[i], &ps[trim],
1653                                             j - trim + 1);
1654                                 }
1655                                 /* Skip to end of path. */
1656                                 while (ps[i + 1] != '\0')
1657                                         i++;
1658                                 break;
1659
1660                                 /*
1661                                  * Superuser status.
1662                                  *
1663                                  * '$' for normal users, '#' for root.
1664                                  */
1665                         case '$':
1666                                 ps[i] = (geteuid() != 0) ? '$' : '#';
1667                                 break;
1668
1669                                 /*
1670                                  * A literal \.
1671                                  */
1672                         case '\\':
1673                                 ps[i] = '\\';
1674                                 break;
1675
1676                                 /*
1677                                  * Emit unrecognized formats verbatim.
1678                                  */
1679                         default:
1680                                 ps[i++] = '\\';
1681                                 ps[i] = *fmt;
1682                                 break;
1683                         }
1684                 else
1685                         ps[i] = *fmt;
1686         ps[i] = '\0';
1687         return (ps);
1688 }