bin/sh/parser.c

   1 /*-
   2  * Copyright (c) 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Kenneth Almquist.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * @(#)parser.c 8.7 (Berkeley) 5/16/95
  37  * $FreeBSD: src/bin/sh/parser.c,v 1.58 2006/11/05 18:36:05 stefanf Exp $
  38  * $DragonFly: src/bin/sh/parser.c,v 1.12 2007/01/18 17:03:18 corecode Exp $
  39  */
  40
  41 #include <stdlib.h>
  42 #include <unistd.h>
  43
  44 #include "shell.h"
  45 #include "parser.h"
  46 #include "nodes.h"
  47 #include "expand.h"     /* defines rmescapes() */
  48 #include "syntax.h"
  49 #include "options.h"
  50 #include "input.h"
  51 #include "output.h"
  52 #include "var.h"
  53 #include "error.h"
  54 #include "memalloc.h"
  55 #include "mystring.h"
  56 #include "alias.h"
  57 #include "show.h"
  58 #include "eval.h"
  59 #ifndef NO_HISTORY
  60 #include "myhistedit.h"
  61 #endif
  62
  63 /*
  64  * Shell command parser.
  65  */
  66
  67 #define EOFMARKLEN      79
  68 #define PROMPTLEN       128
  69
  70 /* values returned by readtoken */
  71 #include "token.h"
  72
  73
  74
  75 struct heredoc {
  76         struct heredoc *next;   /* next here document in list */
  77         union node *here;               /* redirection node */
  78         char *eofmark;          /* string indicating end of input */
  79         int striptabs;          /* if set, strip leading tabs */
  80 };
  81
  82
  83
  84 STATIC struct heredoc *heredoclist;     /* list of here documents to read */
  85 STATIC int parsebackquote;      /* nonzero if we are inside backquotes */
  86 STATIC int doprompt;            /* if set, prompt the user */
  87 STATIC int needprompt;          /* true if interactive and at start of line */
  88 STATIC int lasttoken;           /* last token read */
  89 MKINIT int tokpushback;         /* last token pushed back */
  90 STATIC char *wordtext;          /* text of last word returned by readtoken */
  91 /*
  92  * 1 == check for kwds
  93  * 2 == also eat newlines
  94  * 3 == check for TNOT
  95  */
  96 MKINIT int checkkwd;
  97 STATIC struct nodelist *backquotelist;
  98 STATIC union node *redirnode;
  99 STATIC struct heredoc *heredoc;
 100 STATIC int quoteflag;           /* set if (part of) last token was quoted */
 101 STATIC int startlinno;          /* line # where last token started */
 102 STATIC int funclinno;           /* line # where the current function started */
 103
 104 /* XXX When 'noaliases' is set to one, no alias expansion takes place. */
 105 static int noaliases = 0;
 106
 107
 108 STATIC union node *list(int);
 109 STATIC union node *andor(void);
 110 STATIC union node *pipeline(void);
 111 STATIC union node *command(void);
 112 STATIC union node *simplecmd(union node **, union node *);
 113 STATIC union node *makename(void);
 114 STATIC void parsefname(void);
 115 STATIC void parseheredoc(void);
 116 STATIC int peektoken(void);
 117 STATIC int readtoken(void);
 118 STATIC int xxreadtoken(void);
 119 STATIC int readtoken1(int, char const *, char *, int);
 120 STATIC int noexpand(char *);
 121 STATIC void synexpect(int);
 122 STATIC void synerror(const char *);
 123 STATIC void setprompt(int);
 124
 125
 126 /*
 127  * Read and parse a command.  Returns NEOF on end of file.  (NULL is a
 128  * valid parse tree indicating a blank line.)
 129  */
 130
 131 union node *
 132 parsecmd(int interact)
 133 {
 134         int t;
 135
 136         tokpushback = 0;
 137         doprompt = interact;
 138         if (doprompt)
 139                 setprompt(1);
 140         else
 141                 setprompt(0);
 142         needprompt = 0;
 143         t = readtoken();
 144         if (t == TEOF)
 145                 return NEOF;
 146         if (t == TNL)
 147                 return NULL;
 148         tokpushback++;
 149         return list(1);
 150 }
 151
 152
 153 STATIC union node *
 154 list(int nlflag)
 155 {
 156         union node *n1, *n2, *n3;
 157         int tok;
 158
 159         checkkwd = 2;
 160         if (nlflag == 0 && tokendlist[peektoken()])
 161                 return NULL;
 162         n1 = NULL;
 163         for (;;) {
 164                 n2 = andor();
 165                 tok = readtoken();
 166                 if (tok == TBACKGND) {
 167                         if (n2->type == NCMD || n2->type == NPIPE) {
 168                                 n2->ncmd.backgnd = 1;
 169                         } else if (n2->type == NREDIR) {
 170                                 n2->type = NBACKGND;
 171                         } else {
 172                                 n3 = (union node *)stalloc(sizeof (struct nredir));
 173                                 n3->type = NBACKGND;
 174                                 n3->nredir.n = n2;
 175                                 n3->nredir.redirect = NULL;
 176                                 n2 = n3;
 177                         }
 178                 }
 179                 if (n1 == NULL) {
 180                         n1 = n2;
 181                 }
 182                 else {
 183                         n3 = (union node *)stalloc(sizeof (struct nbinary));
 184                         n3->type = NSEMI;
 185                         n3->nbinary.ch1 = n1;
 186                         n3->nbinary.ch2 = n2;
 187                         n1 = n3;
 188                 }
 189                 switch (tok) {
 190                 case TBACKGND:
 191                 case TSEMI:
 192                         tok = readtoken();
 193                         /* FALLTHROUGH */
 194                 case TNL:
 195                         if (tok == TNL) {
 196                                 parseheredoc();
 197                                 if (nlflag)
 198                                         return n1;
 199                         } else {
 200                                 tokpushback++;
 201                         }
 202                         checkkwd = 2;
 203                         if (tokendlist[peektoken()])
 204                                 return n1;
 205                         break;
 206                 case TEOF:
 207                         if (heredoclist)
 208                                 parseheredoc();
 209                         else
 210                                 pungetc();              /* push back EOF on input */
 211                         return n1;
 212                 default:
 213                         if (nlflag)
 214                                 synexpect(-1);
 215                         tokpushback++;
 216                         return n1;
 217                 }
 218         }
 219 }
 220
 221
 222
 223 STATIC union node *
 224 andor(void)
 225 {
 226         union node *n1, *n2, *n3;
 227         int t;
 228
 229         n1 = pipeline();
 230         for (;;) {
 231                 if ((t = readtoken()) == TAND) {
 232                         t = NAND;
 233                 } else if (t == TOR) {
 234                         t = NOR;
 235                 } else {
 236                         tokpushback++;
 237                         return n1;
 238                 }
 239                 n2 = pipeline();
 240                 n3 = (union node *)stalloc(sizeof (struct nbinary));
 241                 n3->type = t;
 242                 n3->nbinary.ch1 = n1;
 243                 n3->nbinary.ch2 = n2;
 244                 n1 = n3;
 245         }
 246 }
 247
 248
 249
 250 STATIC union node *
 251 pipeline(void)
 252 {
 253         union node *n1, *n2, *pipenode;
 254         struct nodelist *lp, *prev;
 255         int negate;
 256
 257         negate = 0;
 258         TRACE(("pipeline: entered\n"));
 259
 260         checkkwd = 3;
 261         while (readtoken() == TNOT)
 262                 negate = !negate;
 263         tokpushback++;
 264
 265         n1 = command();
 266         if (readtoken() == TPIPE) {
 267                 pipenode = (union node *)stalloc(sizeof (struct npipe));
 268                 pipenode->type = NPIPE;
 269                 pipenode->npipe.backgnd = 0;
 270                 lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 271                 pipenode->npipe.cmdlist = lp;
 272                 lp->n = n1;
 273                 do {
 274                         int innernegate = 0;
 275
 276                         checkkwd = 3;
 277                         while (readtoken() == TNOT)
 278                                 innernegate = !innernegate;
 279                         tokpushback++;
 280
 281                         prev = lp;
 282                         lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 283                         lp->n = command();
 284                         prev->next = lp;
 285
 286                         if (innernegate) {
 287                                 n2 = (union node *)stalloc(sizeof (struct nnot));
 288                                 n2->type = NNOT;
 289                                 n2->nnot.com = lp->n;
 290                                 lp->n = n2;
 291                         }
 292                 } while (readtoken() == TPIPE);
 293                 lp->next = NULL;
 294                 n1 = pipenode;
 295         }
 296         tokpushback++;
 297         if (negate) {
 298                 n2 = (union node *)stalloc(sizeof (struct nnot));
 299                 n2->type = NNOT;
 300                 n2->nnot.com = n1;
 301                 return n2;
 302         } else
 303                 return n1;
 304 }
 305
 306
 307
 308 STATIC union node *
 309 command(void)
 310 {
 311         union node *n1, *n2;
 312         union node *ap, **app;
 313         union node *cp, **cpp;
 314         union node *redir, **rpp;
 315         int t;
 316
 317         checkkwd = 2;
 318         redir = NULL;
 319         n1 = NULL;
 320         rpp = &redir;
 321
 322         /* Check for redirection which may precede command */
 323         while (readtoken() == TREDIR) {
 324                 *rpp = n2 = redirnode;
 325                 rpp = &n2->nfile.next;
 326                 parsefname();
 327         }
 328         tokpushback++;
 329
 330         switch (readtoken()) {
 331         case TIF:
 332                 n1 = (union node *)stalloc(sizeof (struct nif));
 333                 n1->type = NIF;
 334                 if ((n1->nif.test = list(0)) == NULL)
 335                         synexpect(-1);
 336                 if (readtoken() != TTHEN)
 337                         synexpect(TTHEN);
 338                 n1->nif.ifpart = list(0);
 339                 n2 = n1;
 340                 while (readtoken() == TELIF) {
 341                         n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
 342                         n2 = n2->nif.elsepart;
 343                         n2->type = NIF;
 344                         if ((n2->nif.test = list(0)) == NULL)
 345                                 synexpect(-1);
 346                         if (readtoken() != TTHEN)
 347                                 synexpect(TTHEN);
 348                         n2->nif.ifpart = list(0);
 349                 }
 350                 if (lasttoken == TELSE)
 351                         n2->nif.elsepart = list(0);
 352                 else {
 353                         n2->nif.elsepart = NULL;
 354                         tokpushback++;
 355                 }
 356                 if (readtoken() != TFI)
 357                         synexpect(TFI);
 358                 checkkwd = 1;
 359                 break;
 360         case TWHILE:
 361         case TUNTIL: {
 362                 int got;
 363                 n1 = (union node *)stalloc(sizeof (struct nbinary));
 364                 n1->type = (lasttoken == TWHILE)? NWHILE : NUNTIL;
 365                 if ((n1->nbinary.ch1 = list(0)) == NULL)
 366                         synexpect(-1);
 367                 if ((got=readtoken()) != TDO) {
 368 TRACE(("expecting DO got %s %s\n", tokname[got], got == TWORD ? wordtext : ""));
 369                         synexpect(TDO);
 370                 }
 371                 n1->nbinary.ch2 = list(0);
 372                 if (readtoken() != TDONE)
 373                         synexpect(TDONE);
 374                 checkkwd = 1;
 375                 break;
 376         }
 377         case TFOR:
 378                 if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
 379                         synerror("Bad for loop variable");
 380                 n1 = (union node *)stalloc(sizeof (struct nfor));
 381                 n1->type = NFOR;
 382                 n1->nfor.var = wordtext;
 383                 if (readtoken() == TWORD && ! quoteflag && equal(wordtext, "in")) {
 384                         app = &ap;
 385                         while (readtoken() == TWORD) {
 386                                 n2 = (union node *)stalloc(sizeof (struct narg));
 387                                 n2->type = NARG;
 388                                 n2->narg.text = wordtext;
 389                                 n2->narg.backquote = backquotelist;
 390                                 *app = n2;
 391                                 app = &n2->narg.next;
 392                         }
 393                         *app = NULL;
 394                         n1->nfor.args = ap;
 395                         if (lasttoken != TNL && lasttoken != TSEMI)
 396                                 synexpect(-1);
 397                 } else {
 398                         static char argvars[5] = {
 399                                 CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'
 400                         };
 401                         n2 = (union node *)stalloc(sizeof (struct narg));
 402                         n2->type = NARG;
 403                         n2->narg.text = argvars;
 404                         n2->narg.backquote = NULL;
 405                         n2->narg.next = NULL;
 406                         n1->nfor.args = n2;
 407                         /*
 408                          * Newline or semicolon here is optional (but note
 409                          * that the original Bourne shell only allowed NL).
 410                          */
 411                         if (lasttoken != TNL && lasttoken != TSEMI)
 412                                 tokpushback++;
 413                 }
 414                 checkkwd = 2;
 415                 if ((t = readtoken()) == TDO)
 416                         t = TDONE;
 417                 else if (t == TBEGIN)
 418                         t = TEND;
 419                 else
 420                         synexpect(-1);
 421                 n1->nfor.body = list(0);
 422                 if (readtoken() != t)
 423                         synexpect(t);
 424                 checkkwd = 1;
 425                 break;
 426         case TCASE:
 427                 n1 = (union node *)stalloc(sizeof (struct ncase));
 428                 n1->type = NCASE;
 429                 if (readtoken() != TWORD)
 430                         synexpect(TWORD);
 431                 n1->ncase.expr = n2 = (union node *)stalloc(sizeof (struct narg));
 432                 n2->type = NARG;
 433                 n2->narg.text = wordtext;
 434                 n2->narg.backquote = backquotelist;
 435                 n2->narg.next = NULL;
 436                 while (readtoken() == TNL);
 437                 if (lasttoken != TWORD || ! equal(wordtext, "in"))
 438                         synerror("expecting \"in\"");
 439                 cpp = &n1->ncase.cases;
 440                 noaliases = 1;  /* turn off alias expansion */
 441                 checkkwd = 2, readtoken();
 442                 while (lasttoken != TESAC) {
 443                         *cpp = cp = (union node *)stalloc(sizeof (struct nclist));
 444                         cp->type = NCLIST;
 445                         app = &cp->nclist.pattern;
 446                         if (lasttoken == TLP)
 447                                 readtoken();
 448                         for (;;) {
 449                                 *app = ap = (union node *)stalloc(sizeof (struct narg));
 450                                 ap->type = NARG;
 451                                 ap->narg.text = wordtext;
 452                                 ap->narg.backquote = backquotelist;
 453                                 if (checkkwd = 2, readtoken() != TPIPE)
 454                                         break;
 455                                 app = &ap->narg.next;
 456                                 readtoken();
 457                         }
 458                         ap->narg.next = NULL;
 459                         if (lasttoken != TRP)
 460                                 noaliases = 0, synexpect(TRP);
 461                         cp->nclist.body = list(0);
 462
 463                         checkkwd = 2;
 464                         if ((t = readtoken()) != TESAC) {
 465                                 if (t != TENDCASE)
 466                                         noaliases = 0, synexpect(TENDCASE);
 467                                 else
 468                                         checkkwd = 2, readtoken();
 469                         }
 470                         cpp = &cp->nclist.next;
 471                 }
 472                 noaliases = 0;  /* reset alias expansion */
 473                 *cpp = NULL;
 474                 checkkwd = 1;
 475                 break;
 476         case TLP:
 477                 n1 = (union node *)stalloc(sizeof (struct nredir));
 478                 n1->type = NSUBSHELL;
 479                 n1->nredir.n = list(0);
 480                 n1->nredir.redirect = NULL;
 481                 if (readtoken() != TRP)
 482                         synexpect(TRP);
 483                 checkkwd = 1;
 484                 break;
 485         case TBEGIN:
 486                 n1 = list(0);
 487                 if (readtoken() != TEND)
 488                         synexpect(TEND);
 489                 checkkwd = 1;
 490                 break;
 491         /* Handle an empty command like other simple commands.  */
 492         case TSEMI:
 493         case TAND:
 494         case TOR:
 495                 /*
 496                  * An empty command before a ; doesn't make much sense, and
 497                  * should certainly be disallowed in the case of `if ;'.
 498                  */
 499                 if (!redir)
 500                         synexpect(-1);
 501         case TNL:
 502         case TEOF:
 503         case TWORD:
 504         case TRP:
 505                 tokpushback++;
 506                 return simplecmd(rpp, redir);
 507         default:
 508                 synexpect(-1);
 509         }
 510
 511         /* Now check for redirection which may follow command */
 512         while (readtoken() == TREDIR) {
 513                 *rpp = n2 = redirnode;
 514                 rpp = &n2->nfile.next;
 515                 parsefname();
 516         }
 517         tokpushback++;
 518         *rpp = NULL;
 519         if (redir) {
 520                 if (n1->type != NSUBSHELL) {
 521                         n2 = (union node *)stalloc(sizeof (struct nredir));
 522                         n2->type = NREDIR;
 523                         n2->nredir.n = n1;
 524                         n1 = n2;
 525                 }
 526                 n1->nredir.redirect = redir;
 527         }
 528         return n1;
 529 }
 530
 531
 532 STATIC union node *
 533 simplecmd(union node **rpp, union node *redir)
 534 {
 535         union node *args, **app;
 536         union node **orig_rpp = rpp;
 537         union node *n = NULL;
 538
 539         /* If we don't have any redirections already, then we must reset */
 540         /* rpp to be the address of the local redir variable.  */
 541         if (redir == 0)
 542                 rpp = &redir;
 543
 544         args = NULL;
 545         app = &args;
 546         /*
 547          * We save the incoming value, because we need this for shell
 548          * functions.  There can not be a redirect or an argument between
 549          * the function name and the open parenthesis.
 550          */
 551         orig_rpp = rpp;
 552
 553         for (;;) {
 554                 if (readtoken() == TWORD) {
 555                         n = (union node *)stalloc(sizeof (struct narg));
 556                         n->type = NARG;
 557                         n->narg.text = wordtext;
 558                         n->narg.backquote = backquotelist;
 559                         *app = n;
 560                         app = &n->narg.next;
 561                 } else if (lasttoken == TREDIR) {
 562                         *rpp = n = redirnode;
 563                         rpp = &n->nfile.next;
 564                         parsefname();   /* read name of redirection file */
 565                 } else if (lasttoken == TLP && app == &args->narg.next
 566                                             && rpp == orig_rpp) {
 567                         /* We have a function */
 568                         if (readtoken() != TRP)
 569                                 synexpect(TRP);
 570                         funclinno = plinno;
 571 #ifdef notdef
 572                         if (! goodname(n->narg.text))
 573                                 synerror("Bad function name");
 574 #endif
 575                         n->type = NDEFUN;
 576                         n->narg.next = command();
 577                         funclinno = 0;
 578                         return n;
 579                 } else {
 580                         tokpushback++;
 581                         break;
 582                 }
 583         }
 584         *app = NULL;
 585         *rpp = NULL;
 586         n = (union node *)stalloc(sizeof (struct ncmd));
 587         n->type = NCMD;
 588         n->ncmd.backgnd = 0;
 589         n->ncmd.args = args;
 590         n->ncmd.redirect = redir;
 591         return n;
 592 }
 593
 594 STATIC union node *
 595 makename(void)
 596 {
 597         union node *n;
 598
 599         n = (union node *)stalloc(sizeof (struct narg));
 600         n->type = NARG;
 601         n->narg.next = NULL;
 602         n->narg.text = wordtext;
 603         n->narg.backquote = backquotelist;
 604         return n;
 605 }
 606
 607 void
 608 fixredir(union node *n, const char *text, int err)
 609 {
 610         TRACE(("Fix redir %s %d\n", text, err));
 611         if (!err)
 612                 n->ndup.vname = NULL;
 613
 614         if (is_digit(text[0]) && text[1] == '\0')
 615                 n->ndup.dupfd = digit_val(text[0]);
 616         else if (text[0] == '-' && text[1] == '\0')
 617                 n->ndup.dupfd = -1;
 618         else {
 619
 620                 if (err)
 621                         synerror("Bad fd number");
 622                 else
 623                         n->ndup.vname = makename();
 624         }
 625 }
 626
 627
 628 STATIC void
 629 parsefname(void)
 630 {
 631         union node *n = redirnode;
 632
 633         if (readtoken() != TWORD)
 634                 synexpect(-1);
 635         if (n->type == NHERE) {
 636                 struct heredoc *here = heredoc;
 637                 struct heredoc *p;
 638                 int i;
 639
 640                 if (quoteflag == 0)
 641                         n->type = NXHERE;
 642                 TRACE(("Here document %d\n", n->type));
 643                 if (here->striptabs) {
 644                         while (*wordtext == '\t')
 645                                 wordtext++;
 646                 }
 647                 if (! noexpand(wordtext) || (i = strlen(wordtext)) == 0 || i > EOFMARKLEN)
 648                         synerror("Illegal eof marker for << redirection");
 649                 rmescapes(wordtext);
 650                 here->eofmark = wordtext;
 651                 here->next = NULL;
 652                 if (heredoclist == NULL)
 653                         heredoclist = here;
 654                 else {
 655                         for (p = heredoclist ; p->next ; p = p->next);
 656                         p->next = here;
 657                 }
 658         } else if (n->type == NTOFD || n->type == NFROMFD) {
 659                 fixredir(n, wordtext, 0);
 660         } else {
 661                 n->nfile.fname = makename();
 662         }
 663 }
 664
 665
 666 /*
 667  * Input any here documents.
 668  */
 669
 670 STATIC void
 671 parseheredoc(void)
 672 {
 673         struct heredoc *here;
 674         union node *n;
 675
 676         while (heredoclist) {
 677                 here = heredoclist;
 678                 heredoclist = here->next;
 679                 if (needprompt) {
 680                         setprompt(2);
 681                         needprompt = 0;
 682                 }
 683                 readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
 684                                 here->eofmark, here->striptabs);
 685                 n = (union node *)stalloc(sizeof (struct narg));
 686                 n->narg.type = NARG;
 687                 n->narg.next = NULL;
 688                 n->narg.text = wordtext;
 689                 n->narg.backquote = backquotelist;
 690                 here->here->nhere.doc = n;
 691         }
 692 }
 693
 694 STATIC int
 695 peektoken(void)
 696 {
 697         int t;
 698
 699         t = readtoken();
 700         tokpushback++;
 701         return (t);
 702 }
 703
 704 STATIC int
 705 readtoken(void)
 706 {
 707         int t;
 708         int savecheckkwd = checkkwd;
 709         struct alias *ap;
 710 #ifdef DEBUG
 711         int alreadyseen = tokpushback;
 712 #endif
 713
 714         top:
 715         t = xxreadtoken();
 716
 717         if (checkkwd) {
 718                 /*
 719                  * eat newlines
 720                  */
 721                 if (checkkwd > 1) {
 722                         checkkwd = 0;
 723                         while (t == TNL) {
 724                                 parseheredoc();
 725                                 t = xxreadtoken();
 726                         }
 727                 } else
 728                         checkkwd = 0;
 729                 /*
 730                  * check for keywords and aliases
 731                  */
 732                 if (t == TWORD && !quoteflag)
 733                 {
 734                         const char * const *pp;
 735
 736                         for (pp = parsekwd; *pp; pp++) {
 737                                 if (**pp == *wordtext && equal(*pp, wordtext))
 738                                 {
 739                                         lasttoken = t = pp - parsekwd + KWDOFFSET;
 740                                         TRACE(("keyword %s recognized\n", tokname[t]));
 741                                         goto out;
 742                                 }
 743                         }
 744                         if (noaliases == 0 &&
 745                             (ap = lookupalias(wordtext, 1)) != NULL) {
 746                                 pushstring(ap->val, strlen(ap->val), ap);
 747                                 checkkwd = savecheckkwd;
 748                                 goto top;
 749                         }
 750                 }
 751 out:
 752                 checkkwd = 0;
 753         }
 754 #ifdef DEBUG
 755         if (!alreadyseen)
 756             TRACE(("token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 757         else
 758             TRACE(("reread token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 759 #endif
 760         return (t);
 761 }
 762
 763
 764 /*
 765  * Read the next input token.
 766  * If the token is a word, we set backquotelist to the list of cmds in
 767  *      backquotes.  We set quoteflag to true if any part of the word was
 768  *      quoted.
 769  * If the token is TREDIR, then we set redirnode to a structure containing
 770  *      the redirection.
 771  * In all cases, the variable startlinno is set to the number of the line
 772  *      on which the token starts.
 773  *
 774  * [Change comment:  here documents and internal procedures]
 775  * [Readtoken shouldn't have any arguments.  Perhaps we should make the
 776  *  word parsing code into a separate routine.  In this case, readtoken
 777  *  doesn't need to have any internal procedures, but parseword does.
 778  *  We could also make parseoperator in essence the main routine, and
 779  *  have parseword (readtoken1?) handle both words and redirection.]
 780  */
 781
 782 #define RETURN(token)   return lasttoken = token
 783
 784 STATIC int
 785 xxreadtoken(void)
 786 {
 787         int c;
 788
 789         if (tokpushback) {
 790                 tokpushback = 0;
 791                 return lasttoken;
 792         }
 793         if (needprompt) {
 794                 setprompt(2);
 795                 needprompt = 0;
 796         }
 797         startlinno = plinno;
 798         for (;;) {      /* until token or start of word found */
 799                 c = pgetc_macro();
 800                 if (c == ' ' || c == '\t')
 801                         continue;               /* quick check for white space first */
 802                 switch (c) {
 803                 case ' ': case '\t':
 804                         continue;
 805                 case '#':
 806                         while ((c = pgetc()) != '\n' && c != PEOF);
 807                         pungetc();
 808                         continue;
 809                 case '\\':
 810                         if (pgetc() == '\n') {
 811                                 startlinno = ++plinno;
 812                                 if (doprompt)
 813                                         setprompt(2);
 814                                 else
 815                                         setprompt(0);
 816                                 continue;
 817                         }
 818                         pungetc();
 819                         goto breakloop;
 820                 case '\n':
 821                         plinno++;
 822                         needprompt = doprompt;
 823                         RETURN(TNL);
 824                 case PEOF:
 825                         RETURN(TEOF);
 826                 case '&':
 827                         if (pgetc() == '&')
 828                                 RETURN(TAND);
 829                         pungetc();
 830                         RETURN(TBACKGND);
 831                 case '|':
 832                         if (pgetc() == '|')
 833                                 RETURN(TOR);
 834                         pungetc();
 835                         RETURN(TPIPE);
 836                 case ';':
 837                         if (pgetc() == ';')
 838                                 RETURN(TENDCASE);
 839                         pungetc();
 840                         RETURN(TSEMI);
 841                 case '(':
 842                         RETURN(TLP);
 843                 case ')':
 844                         RETURN(TRP);
 845                 case '!':
 846                         if (checkkwd == 3)
 847                                 RETURN(TNOT);
 848                         /* else FALLTHROUGH */
 849                 default:
 850                         goto breakloop;
 851                 }
 852         }
 853 breakloop:
 854         return readtoken1(c, BASESYNTAX, NULL, 0);
 855 #undef RETURN
 856 }
 857
 858
 859
 860 /*
 861  * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
 862  * is not NULL, read a here document.  In the latter case, eofmark is the
 863  * word which marks the end of the document and striptabs is true if
 864  * leading tabs should be stripped from the document.  The argument firstc
 865  * is the first character of the input token or document.
 866  *
 867  * Because C does not have internal subroutines, I have simulated them
 868  * using goto's to implement the subroutine linkage.  The following macros
 869  * will run code that appears at the end of readtoken1.
 870  */
 871
 872 #define CHECKEND()      {goto checkend; checkend_return:;}
 873 #define PARSEREDIR()    {goto parseredir; parseredir_return:;}
 874 #define PARSESUB()      {goto parsesub; parsesub_return:;}
 875 #define PARSEBACKQOLD() {oldstyle = 1; goto parsebackq; parsebackq_oldreturn:;}
 876 #define PARSEBACKQNEW() {oldstyle = 0; goto parsebackq; parsebackq_newreturn:;}
 877 #define PARSEARITH()    {goto parsearith; parsearith_return:;}
 878
 879 STATIC int
 880 readtoken1(int firstc, char const *syn, char *eofmark, int striptabs)
 881 {
 882         int c = firstc;
 883         char const * volatile syntax = syn;
 884         char * volatile out;
 885         int len;
 886         char line[EOFMARKLEN + 1];
 887         struct nodelist *bqlist;
 888         volatile int quotef;
 889         volatile int dblquote;
 890         volatile int varnest;   /* levels of variables expansion */
 891         volatile int arinest;   /* levels of arithmetic expansion */
 892         volatile int parenlevel;        /* levels of parens in arithmetic */
 893         volatile int oldstyle;
 894         char const * volatile prevsyntax = NULL;        /* syntax before arithmetic */
 895         int synentry;
 896
 897         startlinno = plinno;
 898         dblquote = 0;
 899         if (syntax == DQSYNTAX)
 900                 dblquote = 1;
 901         quotef = 0;
 902         bqlist = NULL;
 903         varnest = 0;
 904         arinest = 0;
 905         parenlevel = 0;
 906
 907         STARTSTACKSTR(out);
 908         loop: { /* for each line, until end of word */
 909                 CHECKEND();     /* set c to PEOF if at end of here document */
 910                 for (;;) {      /* until end of line or end of word */
 911                         CHECKSTRSPACE(3, out);  /* permit 3 calls to USTPUTC */
 912
 913                         synentry = syntax[c];
 914
 915                         switch(synentry) {
 916                         case CNL:       /* '\n' */
 917                                 if (syntax == BASESYNTAX)
 918                                         goto endword;   /* exit outer loop */
 919                                 USTPUTC(c, out);
 920                                 plinno++;
 921                                 if (doprompt)
 922                                         setprompt(2);
 923                                 else
 924                                         setprompt(0);
 925                                 c = pgetc();
 926                                 goto loop;              /* continue outer loop */
 927                         case CWORD:
 928                                 USTPUTC(c, out);
 929                                 break;
 930                         case CCTL:
 931                                 if (eofmark == NULL || dblquote)
 932                                         USTPUTC(CTLESC, out);
 933                                 USTPUTC(c, out);
 934                                 break;
 935                         case CBACK:     /* backslash */
 936                                 c = pgetc();
 937                                 if (c == PEOF) {
 938                                         USTPUTC('\\', out);
 939                                         pungetc();
 940                                 } else if (c == '\n') {
 941                                         plinno++;
 942                                         if (doprompt)
 943                                                 setprompt(2);
 944                                         else
 945                                                 setprompt(0);
 946                                 } else {
 947                                         if (dblquote && c != '\\' &&
 948                                             c != '`' && c != '$' &&
 949                                             (c != '"' || eofmark != NULL))
 950                                                 USTPUTC('\\', out);
 951                                         if (SQSYNTAX[c] == CCTL)
 952                                                 USTPUTC(CTLESC, out);
 953                                         else if (eofmark == NULL)
 954                                                 USTPUTC(CTLQUOTEMARK, out);
 955                                         USTPUTC(c, out);
 956                                         quotef++;
 957                                 }
 958                                 break;
 959                         case CSQUOTE:
 960                                 if (eofmark == NULL)
 961                                         USTPUTC(CTLQUOTEMARK, out);
 962                                 syntax = SQSYNTAX;
 963                                 break;
 964                         case CDQUOTE:
 965                                 if (eofmark == NULL)
 966                                         USTPUTC(CTLQUOTEMARK, out);
 967                                 syntax = DQSYNTAX;
 968                                 dblquote = 1;
 969                                 break;
 970                         case CENDQUOTE:
 971                                 if (eofmark != NULL && arinest == 0 &&
 972                                     varnest == 0) {
 973                                         USTPUTC(c, out);
 974                                 } else {
 975                                         if (arinest) {
 976                                                 syntax = ARISYNTAX;
 977                                                 dblquote = 0;
 978                                         } else if (eofmark == NULL) {
 979                                                 syntax = BASESYNTAX;
 980                                                 dblquote = 0;
 981                                         }
 982                                         quotef++;
 983                                 }
 984                                 break;
 985                         case CVAR:      /* '$' */
 986                                 PARSESUB();             /* parse substitution */
 987                                 break;
 988                         case CENDVAR:   /* '}' */
 989                                 if (varnest > 0) {
 990                                         varnest--;
 991                                         USTPUTC(CTLENDVAR, out);
 992                                 } else {
 993                                         USTPUTC(c, out);
 994                                 }
 995                                 break;
 996                         case CLP:       /* '(' in arithmetic */
 997                                 parenlevel++;
 998                                 USTPUTC(c, out);
 999                                 break;
1000                         case CRP:       /* ')' in arithmetic */
1001                                 if (parenlevel > 0) {
1002                                         USTPUTC(c, out);
1003                                         --parenlevel;
1004                                 } else {
1005                                         if (pgetc() == ')') {
1006                                                 if (--arinest == 0) {
1007                                                         USTPUTC(CTLENDARI, out);
1008                                                         syntax = prevsyntax;
1009                                                         if (syntax == DQSYNTAX)
1010                                                                 dblquote = 1;
1011                                                         else
1012                                                                 dblquote = 0;
1013                                                 } else
1014                                                         USTPUTC(')', out);
1015                                         } else {
1016                                                 /*
1017                                                  * unbalanced parens
1018                                                  *  (don't 2nd guess - no error)
1019                                                  */
1020                                                 pungetc();
1021                                                 USTPUTC(')', out);
1022                                         }
1023                                 }
1024                                 break;
1025                         case CBQUOTE:   /* '`' */
1026                                 PARSEBACKQOLD();
1027                                 break;
1028                         case CEOF:
1029                                 goto endword;           /* exit outer loop */
1030                         default:
1031                                 if (varnest == 0)
1032                                         goto endword;   /* exit outer loop */
1033                                 USTPUTC(c, out);
1034                         }
1035                         c = pgetc_macro();
1036                 }
1037         }
1038 endword:
1039         if (syntax == ARISYNTAX)
1040                 synerror("Missing '))'");
1041         if (syntax != BASESYNTAX && ! parsebackquote && eofmark == NULL)
1042                 synerror("Unterminated quoted string");
1043         if (varnest != 0) {
1044                 startlinno = plinno;
1045                 synerror("Missing '}'");
1046         }
1047         USTPUTC('\0', out);
1048         len = out - stackblock();
1049         out = stackblock();
1050         if (eofmark == NULL) {
1051                 if ((c == '>' || c == '<')
1052                  && quotef == 0
1053                  && len <= 2
1054                  && (*out == '\0' || is_digit(*out))) {
1055                         PARSEREDIR();
1056                         return lasttoken = TREDIR;
1057                 } else {
1058                         pungetc();
1059                 }
1060         }
1061         quoteflag = quotef;
1062         backquotelist = bqlist;
1063         grabstackblock(len);
1064         wordtext = out;
1065         return lasttoken = TWORD;
1066 /* end of readtoken routine */
1067
1068
1069
1070 /*
1071  * Check to see whether we are at the end of the here document.  When this
1072  * is called, c is set to the first character of the next input line.  If
1073  * we are at the end of the here document, this routine sets the c to PEOF.
1074  */
1075
1076 checkend: {
1077         if (eofmark) {
1078                 if (striptabs) {
1079                         while (c == '\t')
1080                                 c = pgetc();
1081                 }
1082                 if (c == *eofmark) {
1083                         if (pfgets(line, sizeof line) != NULL) {
1084                                 char *p, *q;
1085
1086                                 p = line;
1087                                 for (q = eofmark + 1 ; *q && *p == *q ; p++, q++);
1088                                 if (*p == '\n' && *q == '\0') {
1089                                         c = PEOF;
1090                                         plinno++;
1091                                         needprompt = doprompt;
1092                                 } else {
1093                                         pushstring(line, strlen(line), NULL);
1094                                 }
1095                         }
1096                 }
1097         }
1098         goto checkend_return;
1099 }
1100
1101
1102 /*
1103  * Parse a redirection operator.  The variable "out" points to a string
1104  * specifying the fd to be redirected.  The variable "c" contains the
1105  * first character of the redirection operator.
1106  */
1107
1108 parseredir: {
1109         char fd = *out;
1110         union node *np;
1111
1112         np = (union node *)stalloc(sizeof (struct nfile));
1113         if (c == '>') {
1114                 np->nfile.fd = 1;
1115                 c = pgetc();
1116                 if (c == '>')
1117                         np->type = NAPPEND;
1118                 else if (c == '&')
1119                         np->type = NTOFD;
1120                 else if (c == '|')
1121                         np->type = NCLOBBER;
1122                 else {
1123                         np->type = NTO;
1124                         pungetc();
1125                 }
1126         } else {        /* c == '<' */
1127                 np->nfile.fd = 0;
1128                 c = pgetc();
1129                 if (c == '<') {
1130                         if (sizeof (struct nfile) != sizeof (struct nhere)) {
1131                                 np = (union node *)stalloc(sizeof (struct nhere));
1132                                 np->nfile.fd = 0;
1133                         }
1134                         np->type = NHERE;
1135                         heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
1136                         heredoc->here = np;
1137                         if ((c = pgetc()) == '-') {
1138                                 heredoc->striptabs = 1;
1139                         } else {
1140                                 heredoc->striptabs = 0;
1141                                 pungetc();
1142                         }
1143                 } else if (c == '&')
1144                         np->type = NFROMFD;
1145                 else if (c == '>')
1146                         np->type = NFROMTO;
1147                 else {
1148                         np->type = NFROM;
1149                         pungetc();
1150                 }
1151         }
1152         if (fd != '\0')
1153                 np->nfile.fd = digit_val(fd);
1154         redirnode = np;
1155         goto parseredir_return;
1156 }
1157
1158
1159 /*
1160  * Parse a substitution.  At this point, we have read the dollar sign
1161  * and nothing else.
1162  */
1163
1164 parsesub: {
1165         char buf[10];
1166         int subtype;
1167         int typeloc;
1168         int flags;
1169         char *p;
1170         static const char types[] = "}-+?=";
1171         int bracketed_name = 0; /* used to handle ${[0-9]*} variables */
1172         int i;
1173         int linno;
1174         int length;
1175
1176         c = pgetc();
1177         if (c != '(' && c != '{' && (is_eof(c) || !is_name(c)) &&
1178             !is_special(c)) {
1179                 USTPUTC('$', out);
1180                 pungetc();
1181         } else if (c == '(') {  /* $(command) or $((arith)) */
1182                 if (pgetc() == '(') {
1183                         PARSEARITH();
1184                 } else {
1185                         pungetc();
1186                         PARSEBACKQNEW();
1187                 }
1188         } else {
1189                 USTPUTC(CTLVAR, out);
1190                 typeloc = out - stackblock();
1191                 USTPUTC(VSNORMAL, out);
1192                 subtype = VSNORMAL;
1193                 flags = 0;
1194                 if (c == '{') {
1195                         bracketed_name = 1;
1196                         c = pgetc();
1197                         if (c == '#') {
1198                                 if ((c = pgetc()) == '}')
1199                                         c = '#';
1200                                 else
1201                                         subtype = VSLENGTH;
1202                         }
1203                         else
1204                                 subtype = 0;
1205                 }
1206                 if (!is_eof(c) && is_name(c)) {
1207                         length = 0;
1208                         do {
1209                                 STPUTC(c, out);
1210                                 c = pgetc();
1211                                 length++;
1212                         } while (!is_eof(c) && is_in_name(c));
1213                         if (length == 6 &&
1214                             strncmp(out - length, "LINENO", length) == 0) {
1215                                 /* Replace the variable name with the
1216                                  * current line number. */
1217                                 linno = plinno;
1218                                 if (funclinno != 0)
1219                                         linno -= funclinno - 1;
1220                                 snprintf(buf, sizeof(buf), "%d", linno);
1221                                 STADJUST(-6, out);
1222                                 for (i = 0; buf[i] != '\0'; i++)
1223                                         STPUTC(buf[i], out);
1224                                 flags |= VSLINENO;
1225                         }
1226                 } else if (is_digit(c)) {
1227                         if (bracketed_name) {
1228                                 do {
1229                                         STPUTC(c, out);
1230                                         c = pgetc();
1231                                 } while (is_digit(c));
1232                         } else {
1233                                 STPUTC(c, out);
1234                                 c = pgetc();
1235                         }
1236                 } else {
1237                         if (! is_special(c)) {
1238                                 subtype = VSERROR;
1239                                 if (c == '}')
1240                                         pungetc();
1241                                 else
1242                                         USTPUTC(c, out);
1243                         } else {
1244                                 USTPUTC(c, out);
1245                                 c = pgetc();
1246                         }
1247                 }
1248                 if (subtype == 0) {
1249                         switch (c) {
1250                         case ':':
1251                                 flags |= VSNUL;
1252                                 c = pgetc();
1253                                 /*FALLTHROUGH*/
1254                         default:
1255                                 p = strchr(types, c);
1256                                 if (p == NULL) {
1257                                         if (flags == VSNUL)
1258                                                 STPUTC(':', out);
1259                                         STPUTC(c, out);
1260                                         subtype = VSERROR;
1261                                 } else
1262                                         subtype = p - types + VSNORMAL;
1263                                 break;
1264                         case '%':
1265                         case '#':
1266                                 {
1267                                         int cc = c;
1268                                         subtype = c == '#' ? VSTRIMLEFT :
1269                                                              VSTRIMRIGHT;
1270                                         c = pgetc();
1271                                         if (c == cc)
1272                                                 subtype++;
1273                                         else
1274                                                 pungetc();
1275                                         break;
1276                                 }
1277                         }
1278                 } else if (subtype != VSERROR) {
1279                         pungetc();
1280                 }
1281                 STPUTC('=', out);
1282                 if (subtype != VSLENGTH && (dblquote || arinest))
1283                         flags |= VSQUOTE;
1284                 *(stackblock() + typeloc) = subtype | flags;
1285                 if (subtype != VSNORMAL)
1286                         varnest++;
1287         }
1288         goto parsesub_return;
1289 }
1290
1291
1292 /*
1293  * Called to parse command substitutions.  Newstyle is set if the command
1294  * is enclosed inside $(...); nlpp is a pointer to the head of the linked
1295  * list of commands (passed by reference), and savelen is the number of
1296  * characters on the top of the stack which must be preserved.
1297  */
1298
1299 parsebackq: {
1300         struct nodelist **nlpp;
1301         int savepbq;
1302         union node *n;
1303         char *volatile str;
1304         struct jmploc jmploc;
1305         struct jmploc *volatile savehandler;
1306         int savelen;
1307         volatile int saveprompt;
1308
1309         savepbq = parsebackquote;
1310         if (setjmp(jmploc.loc)) {
1311                 if (str)
1312                         ckfree(str);
1313                 parsebackquote = 0;
1314                 handler = savehandler;
1315                 longjmp(handler->loc, 1);
1316         }
1317         INTOFF;
1318         str = NULL;
1319         savelen = out - stackblock();
1320         if (savelen > 0) {
1321                 str = ckmalloc(savelen);
1322                 memcpy(str, stackblock(), savelen);
1323         }
1324         savehandler = handler;
1325         handler = &jmploc;
1326         INTON;
1327         if (oldstyle) {
1328                 /* We must read until the closing backquote, giving special
1329                    treatment to some slashes, and then push the string and
1330                    reread it as input, interpreting it normally.  */
1331                 char *pout;
1332                 int pc;
1333                 int psavelen;
1334                 char *pstr;
1335
1336
1337                 STARTSTACKSTR(pout);
1338                 for (;;) {
1339                         if (needprompt) {
1340                                 setprompt(2);
1341                                 needprompt = 0;
1342                         }
1343                         switch (pc = pgetc()) {
1344                         case '`':
1345                                 goto done;
1346
1347                         case '\\':
1348                                 if ((pc = pgetc()) == '\n') {
1349                                         plinno++;
1350                                         if (doprompt)
1351                                                 setprompt(2);
1352                                         else
1353                                                 setprompt(0);
1354                                         /*
1355                                          * If eating a newline, avoid putting
1356                                          * the newline into the new character
1357                                          * stream (via the STPUTC after the
1358                                          * switch).
1359                                          */
1360                                         continue;
1361                                 }
1362                                 if (pc != '\\' && pc != '`' && pc != '$'
1363                                     && (!dblquote || pc != '"'))
1364                                         STPUTC('\\', pout);
1365                                 break;
1366
1367                         case '\n':
1368                                 plinno++;
1369                                 needprompt = doprompt;
1370                                 break;
1371
1372                         case PEOF:
1373                                 startlinno = plinno;
1374                                 synerror("EOF in backquote substitution");
1375                                 break;
1376
1377                         default:
1378                                 break;
1379                         }
1380                         STPUTC(pc, pout);
1381                 }
1382 done:
1383                 STPUTC('\0', pout);
1384                 psavelen = pout - stackblock();
1385                 if (psavelen > 0) {
1386                         pstr = ckmalloc(psavelen);
1387                         memcpy(pstr, stackblock(), psavelen);
1388                         setinputstring(pstr, 1);
1389                 }
1390         }
1391         nlpp = &bqlist;
1392         while (*nlpp)
1393                 nlpp = &(*nlpp)->next;
1394         *nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
1395         (*nlpp)->next = NULL;
1396         parsebackquote = oldstyle;
1397
1398         if (oldstyle) {
1399                 saveprompt = doprompt;
1400                 doprompt = 0;
1401         }
1402
1403         n = list(0);
1404
1405         if (oldstyle)
1406                 doprompt = saveprompt;
1407         else {
1408                 if (readtoken() != TRP)
1409                         synexpect(TRP);
1410         }
1411
1412         (*nlpp)->n = n;
1413         if (oldstyle) {
1414                 /*
1415                  * Start reading from old file again, ignoring any pushed back
1416                  * tokens left from the backquote parsing
1417                  */
1418                 popfile();
1419                 tokpushback = 0;
1420         }
1421         while (stackblocksize() <= savelen)
1422                 growstackblock();
1423         STARTSTACKSTR(out);
1424         if (str) {
1425                 memcpy(out, str, savelen);
1426                 STADJUST(savelen, out);
1427                 INTOFF;
1428                 ckfree(str);
1429                 str = NULL;
1430                 INTON;
1431         }
1432         parsebackquote = savepbq;
1433         handler = savehandler;
1434         if (arinest || dblquote)
1435                 USTPUTC(CTLBACKQ | CTLQUOTE, out);
1436         else
1437                 USTPUTC(CTLBACKQ, out);
1438         if (oldstyle)
1439                 goto parsebackq_oldreturn;
1440         else
1441                 goto parsebackq_newreturn;
1442 }
1443
1444 /*
1445  * Parse an arithmetic expansion (indicate start of one and set state)
1446  */
1447 parsearith: {
1448
1449         if (++arinest == 1) {
1450                 prevsyntax = syntax;
1451                 syntax = ARISYNTAX;
1452                 USTPUTC(CTLARI, out);
1453                 if (dblquote)
1454                         USTPUTC('"',out);
1455                 else
1456                         USTPUTC(' ',out);
1457         } else {
1458                 /*
1459                  * we collapse embedded arithmetic expansion to
1460                  * parenthesis, which should be equivalent
1461                  */
1462                 USTPUTC('(', out);
1463         }
1464         goto parsearith_return;
1465 }
1466
1467 } /* end of readtoken */
1468
1469
1470
1471 #ifdef mkinit
1472 RESET {
1473         tokpushback = 0;
1474         checkkwd = 0;
1475 }
1476 #endif
1477
1478 /*
1479  * Returns true if the text contains nothing to expand (no dollar signs
1480  * or backquotes).
1481  */
1482
1483 STATIC int
1484 noexpand(char *text)
1485 {
1486         char *p;
1487         char c;
1488
1489         p = text;
1490         while ((c = *p++) != '\0') {
1491                 if ( c == CTLQUOTEMARK)
1492                         continue;
1493                 if (c == CTLESC)
1494                         p++;
1495                 else if (BASESYNTAX[(int)c] == CCTL)
1496                         return 0;
1497         }
1498         return 1;
1499 }
1500
1501
1502 /*
1503  * Return true if the argument is a legal variable name (a letter or
1504  * underscore followed by zero or more letters, underscores, and digits).
1505  */
1506
1507 int
1508 goodname(char *name)
1509 {
1510         char *p;
1511
1512         p = name;
1513         if (! is_name(*p))
1514                 return 0;
1515         while (*++p) {
1516                 if (! is_in_name(*p))
1517                         return 0;
1518         }
1519         return 1;
1520 }
1521
1522
1523 /*
1524  * Called when an unexpected token is read during the parse.  The argument
1525  * is the token that is expected, or -1 if more than one type of token can
1526  * occur at this point.
1527  */
1528
1529 STATIC void
1530 synexpect(int token)
1531 {
1532         char msg[64];
1533
1534         if (token >= 0) {
1535                 fmtstr(msg, 64, "%s unexpected (expecting %s)",
1536                         tokname[lasttoken], tokname[token]);
1537         } else {
1538                 fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
1539         }
1540         synerror(msg);
1541 }
1542
1543
1544 STATIC void
1545 synerror(const char *msg)
1546 {
1547         if (commandname)
1548                 outfmt(&errout, "%s: %d: ", commandname, startlinno);
1549         outfmt(&errout, "Syntax error: %s\n", msg);
1550         error(NULL);
1551 }
1552
1553 STATIC void
1554 setprompt(int which)
1555 {
1556         whichprompt = which;
1557
1558 #ifndef NO_HISTORY
1559         if (!el)
1560 #endif
1561                 out2str(getprompt(NULL));
1562 }
1563
1564 /*
1565  * called by editline -- any expansions to the prompt
1566  *    should be added here.
1567  */
1568 const char *
1569 getprompt(void *unused __unused)
1570 {
1571         static char ps[PROMPTLEN];
1572         const char *fmt;
1573         int i, j, trim;
1574
1575         /*
1576          * Select prompt format.
1577          */
1578         switch (whichprompt) {
1579         case 0:
1580                 fmt = "";
1581                 break;
1582         case 1:
1583                 fmt = ps1val();
1584                 break;
1585         case 2:
1586                 fmt = ps2val();
1587                 break;
1588         default:
1589                 return "<internal prompt error>";
1590         }
1591
1592         /*
1593          * Format prompt string.
1594          */
1595         for (i = 0; (i < 127) && (*fmt != '\0'); i++, fmt++)
1596                 if (*fmt == '\\')
1597                         switch (*++fmt) {
1598
1599                                 /*
1600                                  * Hostname.
1601                                  *
1602                                  * \h specifies just the local hostname,
1603                                  * \H specifies fully-qualified hostname.
1604                                  */
1605                         case 'h':
1606                         case 'H':
1607                                 ps[i] = '\0';
1608                                 gethostname(&ps[i], PROMPTLEN - i);
1609                                 /* Skip to end of hostname. */
1610                                 trim = (*fmt == 'h') ? '.' : '\0';
1611                                 while ((ps[i+1] != '\0') && (ps[i+1] != trim))
1612                                         i++;
1613                                 break;
1614
1615                                 /*
1616                                  * Working directory.
1617                                  *
1618                                  * \W specifies just the final component,
1619                                  * \w specifies the entire path.
1620                                  */
1621                         case 'W':
1622                         case 'w':
1623                                 ps[i] = '\0';
1624                                 getcwd(&ps[i], PROMPTLEN - i);
1625                                 if (*fmt == 'W') {
1626                                         /* Final path component only. */
1627                                         trim = 1;
1628                                         for (j = i; ps[j] != '\0'; j++)
1629                                           if (ps[j] == '/')
1630                                                 trim = j + 1;
1631                                         memmove(&ps[i], &ps[trim],
1632                                             j - trim + 1);
1633                                 }
1634                                 /* Skip to end of path. */
1635                                 while (ps[i + 1] != '\0')
1636                                         i++;
1637                                 break;
1638
1639                                 /*
1640                                  * Superuser status.
1641                                  *
1642                                  * '$' for normal users, '#' for root.
1643                                  */
1644                         case '$':
1645                                 ps[i] = (geteuid() != 0) ? '$' : '#';
1646                                 break;
1647
1648                                 /*
1649                                  * A literal \.
1650                                  */
1651                         case '\\':
1652                                 ps[i] = '\\';
1653                                 break;
1654
1655                                 /*
1656                                  * Emit unrecognized formats verbatim.
1657                                  */
1658                         default:
1659                                 ps[i++] = '\\';
1660                                 ps[i] = *fmt;
1661                                 break;
1662                         }
1663                 else
1664                         ps[i] = *fmt;
1665         ps[i] = '\0';
1666         return (ps);
1667 }