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