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