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 <stdio.h>
  42 #include <stdlib.h>
  43 #include <unistd.h>
  44
  45 #include "shell.h"
  46 #include "parser.h"
  47 #include "nodes.h"
  48 #include "expand.h"     /* defines rmescapes() */
  49 #include "syntax.h"
  50 #include "options.h"
  51 #include "input.h"
  52 #include "output.h"
  53 #include "var.h"
  54 #include "error.h"
  55 #include "memalloc.h"
  56 #include "mystring.h"
  57 #include "alias.h"
  58 #include "show.h"
  59 #include "eval.h"
  60 #ifndef NO_HISTORY
  61 #include "myhistedit.h"
  62 #endif
  63
  64 /*
  65  * Shell command parser.
  66  */
  67
  68 #define EOFMARKLEN      79
  69 #define PROMPTLEN       128
  70
  71 /* values returned by readtoken */
  72 #include "token.h"
  73
  74
  75
  76 struct heredoc {
  77         struct heredoc *next;   /* next here document in list */
  78         union node *here;               /* redirection node */
  79         char *eofmark;          /* string indicating end of input */
  80         int striptabs;          /* if set, strip leading tabs */
  81 };
  82
  83
  84
  85 STATIC struct heredoc *heredoclist;     /* list of here documents to read */
  86 STATIC int parsebackquote;      /* nonzero if we are inside backquotes */
  87 STATIC int doprompt;            /* if set, prompt the user */
  88 STATIC int needprompt;          /* true if interactive and at start of line */
  89 STATIC int lasttoken;           /* last token read */
  90 MKINIT int tokpushback;         /* last token pushed back */
  91 STATIC char *wordtext;          /* text of last word returned by readtoken */
  92 /*
  93  * 1 == check for kwds
  94  * 2 == also eat newlines
  95  * 3 == check for TNOT
  96  */
  97 MKINIT int checkkwd;
  98 STATIC struct nodelist *backquotelist;
  99 STATIC union node *redirnode;
 100 STATIC struct heredoc *heredoc;
 101 STATIC int quoteflag;           /* set if (part of) last token was quoted */
 102 STATIC int startlinno;          /* line # where last token started */
 103 STATIC int funclinno;           /* line # where the current function started */
 104
 105 /* XXX When 'noaliases' is set to one, no alias expansion takes place. */
 106 static int noaliases = 0;
 107
 108
 109 STATIC union node *list(int);
 110 STATIC union node *andor(void);
 111 STATIC union node *pipeline(void);
 112 STATIC union node *command(void);
 113 STATIC union node *simplecmd(union node **, union node *);
 114 STATIC union node *makename(void);
 115 STATIC void parsefname(void);
 116 STATIC void parseheredoc(void);
 117 STATIC int peektoken(void);
 118 STATIC int readtoken(void);
 119 STATIC int xxreadtoken(void);
 120 STATIC int readtoken1(int, char const *, char *, int);
 121 STATIC int noexpand(char *);
 122 STATIC void synexpect(int);
 123 STATIC void synerror(const char *);
 124 STATIC void setprompt(int);
 125
 126
 127 /*
 128  * Read and parse a command.  Returns NEOF on end of file.  (NULL is a
 129  * valid parse tree indicating a blank line.)
 130  */
 131
 132 union node *
 133 parsecmd(int interact)
 134 {
 135         int t;
 136
 137         tokpushback = 0;
 138         doprompt = interact;
 139         if (doprompt)
 140                 setprompt(1);
 141         else
 142                 setprompt(0);
 143         needprompt = 0;
 144         t = readtoken();
 145         if (t == TEOF)
 146                 return NEOF;
 147         if (t == TNL)
 148                 return NULL;
 149         tokpushback++;
 150         return list(1);
 151 }
 152
 153
 154 STATIC union node *
 155 list(int nlflag)
 156 {
 157         union node *n1, *n2, *n3;
 158         int tok;
 159
 160         checkkwd = 2;
 161         if (nlflag == 0 && tokendlist[peektoken()])
 162                 return NULL;
 163         n1 = NULL;
 164         for (;;) {
 165                 n2 = andor();
 166                 tok = readtoken();
 167                 if (tok == TBACKGND) {
 168                         if (n2->type == NCMD || n2->type == NPIPE) {
 169                                 n2->ncmd.backgnd = 1;
 170                         } else if (n2->type == NREDIR) {
 171                                 n2->type = NBACKGND;
 172                         } else {
 173                                 n3 = (union node *)stalloc(sizeof (struct nredir));
 174                                 n3->type = NBACKGND;
 175                                 n3->nredir.n = n2;
 176                                 n3->nredir.redirect = NULL;
 177                                 n2 = n3;
 178                         }
 179                 }
 180                 if (n1 == NULL) {
 181                         n1 = n2;
 182                 }
 183                 else {
 184                         n3 = (union node *)stalloc(sizeof (struct nbinary));
 185                         n3->type = NSEMI;
 186                         n3->nbinary.ch1 = n1;
 187                         n3->nbinary.ch2 = n2;
 188                         n1 = n3;
 189                 }
 190                 switch (tok) {
 191                 case TBACKGND:
 192                 case TSEMI:
 193                         tok = readtoken();
 194                         /* FALLTHROUGH */
 195                 case TNL:
 196                         if (tok == TNL) {
 197                                 parseheredoc();
 198                                 if (nlflag)
 199                                         return n1;
 200                         } else {
 201                                 tokpushback++;
 202                         }
 203                         checkkwd = 2;
 204                         if (tokendlist[peektoken()])
 205                                 return n1;
 206                         break;
 207                 case TEOF:
 208                         if (heredoclist)
 209                                 parseheredoc();
 210                         else
 211                                 pungetc();              /* push back EOF on input */
 212                         return n1;
 213                 default:
 214                         if (nlflag)
 215                                 synexpect(-1);
 216                         tokpushback++;
 217                         return n1;
 218                 }
 219         }
 220 }
 221
 222
 223
 224 STATIC union node *
 225 andor(void)
 226 {
 227         union node *n1, *n2, *n3;
 228         int t;
 229
 230         n1 = pipeline();
 231         for (;;) {
 232                 if ((t = readtoken()) == TAND) {
 233                         t = NAND;
 234                 } else if (t == TOR) {
 235                         t = NOR;
 236                 } else {
 237                         tokpushback++;
 238                         return n1;
 239                 }
 240                 n2 = pipeline();
 241                 n3 = (union node *)stalloc(sizeof (struct nbinary));
 242                 n3->type = t;
 243                 n3->nbinary.ch1 = n1;
 244                 n3->nbinary.ch2 = n2;
 245                 n1 = n3;
 246         }
 247 }
 248
 249
 250
 251 STATIC union node *
 252 pipeline(void)
 253 {
 254         union node *n1, *n2, *pipenode;
 255         struct nodelist *lp, *prev;
 256         int negate;
 257
 258         negate = 0;
 259         TRACE(("pipeline: entered\n"));
 260
 261         checkkwd = 3;
 262         while (readtoken() == TNOT)
 263                 negate = !negate;
 264         tokpushback++;
 265
 266         n1 = command();
 267         if (readtoken() == TPIPE) {
 268                 pipenode = (union node *)stalloc(sizeof (struct npipe));
 269                 pipenode->type = NPIPE;
 270                 pipenode->npipe.backgnd = 0;
 271                 lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 272                 pipenode->npipe.cmdlist = lp;
 273                 lp->n = n1;
 274                 do {
 275                         int innernegate = 0;
 276
 277                         checkkwd = 3;
 278                         while (readtoken() == TNOT)
 279                                 innernegate = !innernegate;
 280                         tokpushback++;
 281
 282                         prev = lp;
 283                         lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 284                         lp->n = command();
 285                         prev->next = lp;
 286
 287                         if (innernegate) {
 288                                 n2 = (union node *)stalloc(sizeof (struct nnot));
 289                                 n2->type = NNOT;
 290                                 n2->nnot.com = lp->n;
 291                                 lp->n = n2;
 292                         }
 293                 } while (readtoken() == TPIPE);
 294                 lp->next = NULL;
 295                 n1 = pipenode;
 296         }
 297         tokpushback++;
 298         if (negate) {
 299                 n2 = (union node *)stalloc(sizeof (struct nnot));
 300                 n2->type = NNOT;
 301                 n2->nnot.com = n1;
 302                 return n2;
 303         } else
 304                 return n1;
 305 }
 306
 307
 308
 309 STATIC union node *
 310 command(void)
 311 {
 312         union node *n1, *n2;
 313         union node *ap, **app;
 314         union node *cp, **cpp;
 315         union node *redir, **rpp;
 316         int t;
 317
 318         checkkwd = 2;
 319         redir = NULL;
 320         n1 = NULL;
 321         rpp = &redir;
 322
 323         /* Check for redirection which may precede command */
 324         while (readtoken() == TREDIR) {
 325                 *rpp = n2 = redirnode;
 326                 rpp = &n2->nfile.next;
 327                 parsefname();
 328         }
 329         tokpushback++;
 330
 331         switch (readtoken()) {
 332         case TIF:
 333                 n1 = (union node *)stalloc(sizeof (struct nif));
 334                 n1->type = NIF;
 335                 if ((n1->nif.test = list(0)) == NULL)
 336                         synexpect(-1);
 337                 if (readtoken() != TTHEN)
 338                         synexpect(TTHEN);
 339                 n1->nif.ifpart = list(0);
 340                 n2 = n1;
 341                 while (readtoken() == TELIF) {
 342                         n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
 343                         n2 = n2->nif.elsepart;
 344                         n2->type = NIF;
 345                         if ((n2->nif.test = list(0)) == NULL)
 346                                 synexpect(-1);
 347                         if (readtoken() != TTHEN)
 348                                 synexpect(TTHEN);
 349                         n2->nif.ifpart = list(0);
 350                 }
 351                 if (lasttoken == TELSE)
 352                         n2->nif.elsepart = list(0);
 353                 else {
 354                         n2->nif.elsepart = NULL;
 355                         tokpushback++;
 356                 }
 357                 if (readtoken() != TFI)
 358                         synexpect(TFI);
 359                 checkkwd = 1;
 360                 break;
 361         case TWHILE:
 362         case TUNTIL: {
 363                 int got;
 364                 n1 = (union node *)stalloc(sizeof (struct nbinary));
 365                 n1->type = (lasttoken == TWHILE)? NWHILE : NUNTIL;
 366                 if ((n1->nbinary.ch1 = list(0)) == NULL)
 367                         synexpect(-1);
 368                 if ((got=readtoken()) != TDO) {
 369 TRACE(("expecting DO got %s %s\n", tokname[got], got == TWORD ? wordtext : ""));
 370                         synexpect(TDO);
 371                 }
 372                 n1->nbinary.ch2 = list(0);
 373                 if (readtoken() != TDONE)
 374                         synexpect(TDONE);
 375                 checkkwd = 1;
 376                 break;
 377         }
 378         case TFOR:
 379                 if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
 380                         synerror("Bad for loop variable");
 381                 n1 = (union node *)stalloc(sizeof (struct nfor));
 382                 n1->type = NFOR;
 383                 n1->nfor.var = wordtext;
 384                 if (readtoken() == TWORD && ! quoteflag && equal(wordtext, "in")) {
 385                         app = &ap;
 386                         while (readtoken() == TWORD) {
 387                                 n2 = (union node *)stalloc(sizeof (struct narg));
 388                                 n2->type = NARG;
 389                                 n2->narg.text = wordtext;
 390                                 n2->narg.backquote = backquotelist;
 391                                 *app = n2;
 392                                 app = &n2->narg.next;
 393                         }
 394                         *app = NULL;
 395                         n1->nfor.args = ap;
 396                         if (lasttoken != TNL && lasttoken != TSEMI)
 397                                 synexpect(-1);
 398                 } else {
 399                         static char argvars[5] = {
 400                                 CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'
 401                         };
 402                         n2 = (union node *)stalloc(sizeof (struct narg));
 403                         n2->type = NARG;
 404                         n2->narg.text = argvars;
 405                         n2->narg.backquote = NULL;
 406                         n2->narg.next = NULL;
 407                         n1->nfor.args = n2;
 408                         /*
 409                          * Newline or semicolon here is optional (but note
 410                          * that the original Bourne shell only allowed NL).
 411                          */
 412                         if (lasttoken != TNL && lasttoken != TSEMI)
 413                                 tokpushback++;
 414                 }
 415                 checkkwd = 2;
 416                 if ((t = readtoken()) == TDO)
 417                         t = TDONE;
 418                 else if (t == TBEGIN)
 419                         t = TEND;
 420                 else
 421                         synexpect(-1);
 422                 n1->nfor.body = list(0);
 423                 if (readtoken() != t)
 424                         synexpect(t);
 425                 checkkwd = 1;
 426                 break;
 427         case TCASE:
 428                 n1 = (union node *)stalloc(sizeof (struct ncase));
 429                 n1->type = NCASE;
 430                 if (readtoken() != TWORD)
 431                         synexpect(TWORD);
 432                 n1->ncase.expr = n2 = (union node *)stalloc(sizeof (struct narg));
 433                 n2->type = NARG;
 434                 n2->narg.text = wordtext;
 435                 n2->narg.backquote = backquotelist;
 436                 n2->narg.next = NULL;
 437                 while (readtoken() == TNL);
 438                 if (lasttoken != TWORD || ! equal(wordtext, "in"))
 439                         synerror("expecting \"in\"");
 440                 cpp = &n1->ncase.cases;
 441                 noaliases = 1;  /* turn off alias expansion */
 442                 checkkwd = 2, readtoken();
 443                 while (lasttoken != TESAC) {
 444                         *cpp = cp = (union node *)stalloc(sizeof (struct nclist));
 445                         cp->type = NCLIST;
 446                         app = &cp->nclist.pattern;
 447                         if (lasttoken == TLP)
 448                                 readtoken();
 449                         for (;;) {
 450                                 *app = ap = (union node *)stalloc(sizeof (struct narg));
 451                                 ap->type = NARG;
 452                                 ap->narg.text = wordtext;
 453                                 ap->narg.backquote = backquotelist;
 454                                 if (checkkwd = 2, readtoken() != TPIPE)
 455                                         break;
 456                                 app = &ap->narg.next;
 457                                 readtoken();
 458                         }
 459                         ap->narg.next = NULL;
 460                         if (lasttoken != TRP)
 461                                 noaliases = 0, synexpect(TRP);
 462                         cp->nclist.body = list(0);
 463
 464                         checkkwd = 2;
 465                         if ((t = readtoken()) != TESAC) {
 466                                 if (t != TENDCASE)
 467                                         noaliases = 0, synexpect(TENDCASE);
 468                                 else
 469                                         checkkwd = 2, readtoken();
 470                         }
 471                         cpp = &cp->nclist.next;
 472                 }
 473                 noaliases = 0;  /* reset alias expansion */
 474                 *cpp = NULL;
 475                 checkkwd = 1;
 476                 break;
 477         case TLP:
 478                 n1 = (union node *)stalloc(sizeof (struct nredir));
 479                 n1->type = NSUBSHELL;
 480                 n1->nredir.n = list(0);
 481                 n1->nredir.redirect = NULL;
 482                 if (readtoken() != TRP)
 483                         synexpect(TRP);
 484                 checkkwd = 1;
 485                 break;
 486         case TBEGIN:
 487                 n1 = list(0);
 488                 if (readtoken() != TEND)
 489                         synexpect(TEND);
 490                 checkkwd = 1;
 491                 break;
 492         /* Handle an empty command like other simple commands.  */
 493         case TSEMI:
 494         case TAND:
 495         case TOR:
 496                 /*
 497                  * An empty command before a ; doesn't make much sense, and
 498                  * should certainly be disallowed in the case of `if ;'.
 499                  */
 500                 if (!redir)
 501                         synexpect(-1);
 502         case TNL:
 503         case TEOF:
 504         case TWORD:
 505         case TRP:
 506                 tokpushback++;
 507                 return simplecmd(rpp, redir);
 508         default:
 509                 synexpect(-1);
 510         }
 511
 512         /* Now check for redirection which may follow command */
 513         while (readtoken() == TREDIR) {
 514                 *rpp = n2 = redirnode;
 515                 rpp = &n2->nfile.next;
 516                 parsefname();
 517         }
 518         tokpushback++;
 519         *rpp = NULL;
 520         if (redir) {
 521                 if (n1->type != NSUBSHELL) {
 522                         n2 = (union node *)stalloc(sizeof (struct nredir));
 523                         n2->type = NREDIR;
 524                         n2->nredir.n = n1;
 525                         n1 = n2;
 526                 }
 527                 n1->nredir.redirect = redir;
 528         }
 529         return n1;
 530 }
 531
 532
 533 STATIC union node *
 534 simplecmd(union node **rpp, union node *redir)
 535 {
 536         union node *args, **app;
 537         union node **orig_rpp = rpp;
 538         union node *n = NULL;
 539
 540         /* If we don't have any redirections already, then we must reset */
 541         /* rpp to be the address of the local redir variable.  */
 542         if (redir == 0)
 543                 rpp = &redir;
 544
 545         args = NULL;
 546         app = &args;
 547         /*
 548          * We save the incoming value, because we need this for shell
 549          * functions.  There can not be a redirect or an argument between
 550          * the function name and the open parenthesis.
 551          */
 552         orig_rpp = rpp;
 553
 554         for (;;) {
 555                 if (readtoken() == TWORD) {
 556                         n = (union node *)stalloc(sizeof (struct narg));
 557                         n->type = NARG;
 558                         n->narg.text = wordtext;
 559                         n->narg.backquote = backquotelist;
 560                         *app = n;
 561                         app = &n->narg.next;
 562                 } else if (lasttoken == TREDIR) {
 563                         *rpp = n = redirnode;
 564                         rpp = &n->nfile.next;
 565                         parsefname();   /* read name of redirection file */
 566                 } else if (lasttoken == TLP && app == &args->narg.next
 567                                             && rpp == orig_rpp) {
 568                         /* We have a function */
 569                         if (readtoken() != TRP)
 570                                 synexpect(TRP);
 571                         funclinno = plinno;
 572 #ifdef notdef
 573                         if (! goodname(n->narg.text))
 574                                 synerror("Bad function name");
 575 #endif
 576                         n->type = NDEFUN;
 577                         n->narg.next = command();
 578                         funclinno = 0;
 579                         return n;
 580                 } else {
 581                         tokpushback++;
 582                         break;
 583                 }
 584         }
 585         *app = NULL;
 586         *rpp = NULL;
 587         n = (union node *)stalloc(sizeof (struct ncmd));
 588         n->type = NCMD;
 589         n->ncmd.backgnd = 0;
 590         n->ncmd.args = args;
 591         n->ncmd.redirect = redir;
 592         return n;
 593 }
 594
 595 STATIC union node *
 596 makename(void)
 597 {
 598         union node *n;
 599
 600         n = (union node *)stalloc(sizeof (struct narg));
 601         n->type = NARG;
 602         n->narg.next = NULL;
 603         n->narg.text = wordtext;
 604         n->narg.backquote = backquotelist;
 605         return n;
 606 }
 607
 608 void
 609 fixredir(union node *n, const char *text, int err)
 610 {
 611         TRACE(("Fix redir %s %d\n", text, err));
 612         if (!err)
 613                 n->ndup.vname = NULL;
 614
 615         if (is_digit(text[0]) && text[1] == '\0')
 616                 n->ndup.dupfd = digit_val(text[0]);
 617         else if (text[0] == '-' && text[1] == '\0')
 618                 n->ndup.dupfd = -1;
 619         else {
 620
 621                 if (err)
 622                         synerror("Bad fd number");
 623                 else
 624                         n->ndup.vname = makename();
 625         }
 626 }
 627
 628
 629 STATIC void
 630 parsefname(void)
 631 {
 632         union node *n = redirnode;
 633
 634         if (readtoken() != TWORD)
 635                 synexpect(-1);
 636         if (n->type == NHERE) {
 637                 struct heredoc *here = heredoc;
 638                 struct heredoc *p;
 639                 int i;
 640
 641                 if (quoteflag == 0)
 642                         n->type = NXHERE;
 643                 TRACE(("Here document %d\n", n->type));
 644                 if (here->striptabs) {
 645                         while (*wordtext == '\t')
 646                                 wordtext++;
 647                 }
 648                 if (! noexpand(wordtext) || (i = strlen(wordtext)) == 0 || i > EOFMARKLEN)
 649                         synerror("Illegal eof marker for << redirection");
 650                 rmescapes(wordtext);
 651                 here->eofmark = wordtext;
 652                 here->next = NULL;
 653                 if (heredoclist == NULL)
 654                         heredoclist = here;
 655                 else {
 656                         for (p = heredoclist ; p->next ; p = p->next);
 657                         p->next = here;
 658                 }
 659         } else if (n->type == NTOFD || n->type == NFROMFD) {
 660                 fixredir(n, wordtext, 0);
 661         } else {
 662                 n->nfile.fname = makename();
 663         }
 664 }
 665
 666
 667 /*
 668  * Input any here documents.
 669  */
 670
 671 STATIC void
 672 parseheredoc(void)
 673 {
 674         struct heredoc *here;
 675         union node *n;
 676
 677         while (heredoclist) {
 678                 here = heredoclist;
 679                 heredoclist = here->next;
 680                 if (needprompt) {
 681                         setprompt(2);
 682                         needprompt = 0;
 683                 }
 684                 readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
 685                                 here->eofmark, here->striptabs);
 686                 n = (union node *)stalloc(sizeof (struct narg));
 687                 n->narg.type = NARG;
 688                 n->narg.next = NULL;
 689                 n->narg.text = wordtext;
 690                 n->narg.backquote = backquotelist;
 691                 here->here->nhere.doc = n;
 692         }
 693 }
 694
 695 STATIC int
 696 peektoken(void)
 697 {
 698         int t;
 699
 700         t = readtoken();
 701         tokpushback++;
 702         return (t);
 703 }
 704
 705 STATIC int
 706 readtoken(void)
 707 {
 708         int t;
 709         int savecheckkwd = checkkwd;
 710         struct alias *ap;
 711 #ifdef DEBUG
 712         int alreadyseen = tokpushback;
 713 #endif
 714
 715         top:
 716         t = xxreadtoken();
 717
 718         if (checkkwd) {
 719                 /*
 720                  * eat newlines
 721                  */
 722                 if (checkkwd > 1) {
 723                         checkkwd = 0;
 724                         while (t == TNL) {
 725                                 parseheredoc();
 726                                 t = xxreadtoken();
 727                         }
 728                 } else
 729                         checkkwd = 0;
 730                 /*
 731                  * check for keywords and aliases
 732                  */
 733                 if (t == TWORD && !quoteflag)
 734                 {
 735                         const char * const *pp;
 736
 737                         for (pp = parsekwd; *pp; pp++) {
 738                                 if (**pp == *wordtext && equal(*pp, wordtext))
 739                                 {
 740                                         lasttoken = t = pp - parsekwd + KWDOFFSET;
 741                                         TRACE(("keyword %s recognized\n", tokname[t]));
 742                                         goto out;
 743                                 }
 744                         }
 745                         if (noaliases == 0 &&
 746                             (ap = lookupalias(wordtext, 1)) != NULL) {
 747                                 pushstring(ap->val, strlen(ap->val), ap);
 748                                 checkkwd = savecheckkwd;
 749                                 goto top;
 750                         }
 751                 }
 752 out:
 753                 checkkwd = 0;
 754         }
 755 #ifdef DEBUG
 756         if (!alreadyseen)
 757             TRACE(("token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 758         else
 759             TRACE(("reread token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 760 #endif
 761         return (t);
 762 }
 763
 764
 765 /*
 766  * Read the next input token.
 767  * If the token is a word, we set backquotelist to the list of cmds in
 768  *      backquotes.  We set quoteflag to true if any part of the word was
 769  *      quoted.
 770  * If the token is TREDIR, then we set redirnode to a structure containing
 771  *      the redirection.
 772  * In all cases, the variable startlinno is set to the number of the line
 773  *      on which the token starts.
 774  *
 775  * [Change comment:  here documents and internal procedures]
 776  * [Readtoken shouldn't have any arguments.  Perhaps we should make the
 777  *  word parsing code into a separate routine.  In this case, readtoken
 778  *  doesn't need to have any internal procedures, but parseword does.
 779  *  We could also make parseoperator in essence the main routine, and
 780  *  have parseword (readtoken1?) handle both words and redirection.]
 781  */
 782
 783 #define RETURN(token)   return lasttoken = token
 784
 785 STATIC int
 786 xxreadtoken(void)
 787 {
 788         int c;
 789
 790         if (tokpushback) {
 791                 tokpushback = 0;
 792                 return lasttoken;
 793         }
 794         if (needprompt) {
 795                 setprompt(2);
 796                 needprompt = 0;
 797         }
 798         startlinno = plinno;
 799         for (;;) {      /* until token or start of word found */
 800                 c = pgetc_macro();
 801                 if (c == ' ' || c == '\t')
 802                         continue;               /* quick check for white space first */
 803                 switch (c) {
 804                 case ' ': case '\t':
 805                         continue;
 806                 case '#':
 807                         while ((c = pgetc()) != '\n' && c != PEOF);
 808                         pungetc();
 809                         continue;
 810                 case '\\':
 811                         if (pgetc() == '\n') {
 812                                 startlinno = ++plinno;
 813                                 if (doprompt)
 814                                         setprompt(2);
 815                                 else
 816                                         setprompt(0);
 817                                 continue;
 818                         }
 819                         pungetc();
 820                         goto breakloop;
 821                 case '\n':
 822                         plinno++;
 823                         needprompt = doprompt;
 824                         RETURN(TNL);
 825                 case PEOF:
 826                         RETURN(TEOF);
 827                 case '&':
 828                         if (pgetc() == '&')
 829                                 RETURN(TAND);
 830                         pungetc();
 831                         RETURN(TBACKGND);
 832                 case '|':
 833                         if (pgetc() == '|')
 834                                 RETURN(TOR);
 835                         pungetc();
 836                         RETURN(TPIPE);
 837                 case ';':
 838                         if (pgetc() == ';')
 839                                 RETURN(TENDCASE);
 840                         pungetc();
 841                         RETURN(TSEMI);
 842                 case '(':
 843                         RETURN(TLP);
 844                 case ')':
 845                         RETURN(TRP);
 846                 case '!':
 847                         if (checkkwd == 3)
 848                                 RETURN(TNOT);
 849                         /* else FALLTHROUGH */
 850                 default:
 851                         goto breakloop;
 852                 }
 853         }
 854 breakloop:
 855         return readtoken1(c, BASESYNTAX, NULL, 0);
 856 #undef RETURN
 857 }
 858
 859
 860
 861 /*
 862  * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
 863  * is not NULL, read a here document.  In the latter case, eofmark is the
 864  * word which marks the end of the document and striptabs is true if
 865  * leading tabs should be stripped from the document.  The argument firstc
 866  * is the first character of the input token or document.
 867  *
 868  * Because C does not have internal subroutines, I have simulated them
 869  * using goto's to implement the subroutine linkage.  The following macros
 870  * will run code that appears at the end of readtoken1.
 871  */
 872
 873 #define CHECKEND()      {goto checkend; checkend_return:;}
 874 #define PARSEREDIR()    {goto parseredir; parseredir_return:;}
 875 #define PARSESUB()      {goto parsesub; parsesub_return:;}
 876 #define PARSEBACKQOLD() {oldstyle = 1; goto parsebackq; parsebackq_oldreturn:;}
 877 #define PARSEBACKQNEW() {oldstyle = 0; goto parsebackq; parsebackq_newreturn:;}
 878 #define PARSEARITH()    {goto parsearith; parsearith_return:;}
 879
 880 STATIC int
 881 readtoken1(int firstc, char const *syn, char *eofmark, int striptabs)
 882 {
 883         int c = firstc;
 884         char const * volatile syntax = syn;
 885         char * volatile out;
 886         int len;
 887         char line[EOFMARKLEN + 1];
 888         struct nodelist *bqlist;
 889         volatile int quotef;
 890         volatile int dblquote;
 891         volatile int varnest;   /* levels of variables expansion */
 892         volatile int arinest;   /* levels of arithmetic expansion */
 893         volatile int parenlevel;        /* levels of parens in arithmetic */
 894         volatile int oldstyle;
 895         char const * volatile prevsyntax = NULL;        /* syntax before arithmetic */
 896         int synentry;
 897
 898         startlinno = plinno;
 899         dblquote = 0;
 900         if (syntax == DQSYNTAX)
 901                 dblquote = 1;
 902         quotef = 0;
 903         bqlist = NULL;
 904         varnest = 0;
 905         arinest = 0;
 906         parenlevel = 0;
 907
 908         STARTSTACKSTR(out);
 909         loop: { /* for each line, until end of word */
 910                 CHECKEND();     /* set c to PEOF if at end of here document */
 911                 for (;;) {      /* until end of line or end of word */
 912                         CHECKSTRSPACE(3, out);  /* permit 3 calls to USTPUTC */
 913
 914                         synentry = syntax[c];
 915
 916                         switch(synentry) {
 917                         case CNL:       /* '\n' */
 918                                 if (syntax == BASESYNTAX)
 919                                         goto endword;   /* exit outer loop */
 920                                 USTPUTC(c, out);
 921                                 plinno++;
 922                                 if (doprompt)
 923                                         setprompt(2);
 924                                 else
 925                                         setprompt(0);
 926                                 c = pgetc();
 927                                 goto loop;              /* continue outer loop */
 928                         case CWORD:
 929                                 USTPUTC(c, out);
 930                                 break;
 931                         case CCTL:
 932                                 if (eofmark == NULL || dblquote)
 933                                         USTPUTC(CTLESC, out);
 934                                 USTPUTC(c, out);
 935                                 break;
 936                         case CBACK:     /* backslash */
 937                                 c = pgetc();
 938                                 if (c == PEOF) {
 939                                         USTPUTC('\\', out);
 940                                         pungetc();
 941                                 } else if (c == '\n') {
 942                                         plinno++;
 943                                         if (doprompt)
 944                                                 setprompt(2);
 945                                         else
 946                                                 setprompt(0);
 947                                 } else {
 948                                         if (dblquote && c != '\\' &&
 949                                             c != '`' && c != '$' &&
 950                                             (c != '"' || eofmark != NULL))
 951                                                 USTPUTC('\\', out);
 952                                         if (SQSYNTAX[c] == CCTL)
 953                                                 USTPUTC(CTLESC, out);
 954                                         else if (eofmark == NULL)
 955                                                 USTPUTC(CTLQUOTEMARK, out);
 956                                         USTPUTC(c, out);
 957                                         quotef++;
 958                                 }
 959                                 break;
 960                         case CSQUOTE:
 961                                 if (eofmark == NULL)
 962                                         USTPUTC(CTLQUOTEMARK, out);
 963                                 syntax = SQSYNTAX;
 964                                 break;
 965                         case CDQUOTE:
 966                                 if (eofmark == NULL)
 967                                         USTPUTC(CTLQUOTEMARK, out);
 968                                 syntax = DQSYNTAX;
 969                                 dblquote = 1;
 970                                 break;
 971                         case CENDQUOTE:
 972                                 if (eofmark != NULL && arinest == 0 &&
 973                                     varnest == 0) {
 974                                         USTPUTC(c, out);
 975                                 } else {
 976                                         if (arinest) {
 977                                                 syntax = ARISYNTAX;
 978                                                 dblquote = 0;
 979                                         } else if (eofmark == NULL) {
 980                                                 syntax = BASESYNTAX;
 981                                                 dblquote = 0;
 982                                         }
 983                                         quotef++;
 984                                 }
 985                                 break;
 986                         case CVAR:      /* '$' */
 987                                 PARSESUB();             /* parse substitution */
 988                                 break;
 989                         case CENDVAR:   /* '}' */
 990                                 if (varnest > 0) {
 991                                         varnest--;
 992                                         USTPUTC(CTLENDVAR, out);
 993                                 } else {
 994                                         USTPUTC(c, out);
 995                                 }
 996                                 break;
 997                         case CLP:       /* '(' in arithmetic */
 998                                 parenlevel++;
 999                                 USTPUTC(c, out);
1000                                 break;
1001                         case CRP:       /* ')' in arithmetic */
1002                                 if (parenlevel > 0) {
1003                                         USTPUTC(c, out);
1004                                         --parenlevel;
1005                                 } else {
1006                                         if (pgetc() == ')') {
1007                                                 if (--arinest == 0) {
1008                                                         USTPUTC(CTLENDARI, out);
1009                                                         syntax = prevsyntax;
1010                                                         if (syntax == DQSYNTAX)
1011                                                                 dblquote = 1;
1012                                                         else
1013                                                                 dblquote = 0;
1014                                                 } else
1015                                                         USTPUTC(')', out);
1016                                         } else {
1017                                                 /*
1018                                                  * unbalanced parens
1019                                                  *  (don't 2nd guess - no error)
1020                                                  */
1021                                                 pungetc();
1022                                                 USTPUTC(')', out);
1023                                         }
1024                                 }
1025                                 break;
1026                         case CBQUOTE:   /* '`' */
1027                                 PARSEBACKQOLD();
1028                                 break;
1029                         case CEOF:
1030                                 goto endword;           /* exit outer loop */
1031                         default:
1032                                 if (varnest == 0)
1033                                         goto endword;   /* exit outer loop */
1034                                 USTPUTC(c, out);
1035                         }
1036                         c = pgetc_macro();
1037                 }
1038         }
1039 endword:
1040         if (syntax == ARISYNTAX)
1041                 synerror("Missing '))'");
1042         if (syntax != BASESYNTAX && ! parsebackquote && eofmark == NULL)
1043                 synerror("Unterminated quoted string");
1044         if (varnest != 0) {
1045                 startlinno = plinno;
1046                 synerror("Missing '}'");
1047         }
1048         USTPUTC('\0', out);
1049         len = out - stackblock();
1050         out = stackblock();
1051         if (eofmark == NULL) {
1052                 if ((c == '>' || c == '<')
1053                  && quotef == 0
1054                  && len <= 2
1055                  && (*out == '\0' || is_digit(*out))) {
1056                         PARSEREDIR();
1057                         return lasttoken = TREDIR;
1058                 } else {
1059                         pungetc();
1060                 }
1061         }
1062         quoteflag = quotef;
1063         backquotelist = bqlist;
1064         grabstackblock(len);
1065         wordtext = out;
1066         return lasttoken = TWORD;
1067 /* end of readtoken routine */
1068
1069
1070
1071 /*
1072  * Check to see whether we are at the end of the here document.  When this
1073  * is called, c is set to the first character of the next input line.  If
1074  * we are at the end of the here document, this routine sets the c to PEOF.
1075  */
1076
1077 checkend: {
1078         if (eofmark) {
1079                 if (striptabs) {
1080                         while (c == '\t')
1081                                 c = pgetc();
1082                 }
1083                 if (c == *eofmark) {
1084                         if (pfgets(line, sizeof line) != NULL) {
1085                                 char *p, *q;
1086
1087                                 p = line;
1088                                 for (q = eofmark + 1 ; *q && *p == *q ; p++, q++);
1089                                 if (*p == '\n' && *q == '\0') {
1090                                         c = PEOF;
1091                                         plinno++;
1092                                         needprompt = doprompt;
1093                                 } else {
1094                                         pushstring(line, strlen(line), NULL);
1095                                 }
1096                         }
1097                 }
1098         }
1099         goto checkend_return;
1100 }
1101
1102
1103 /*
1104  * Parse a redirection operator.  The variable "out" points to a string
1105  * specifying the fd to be redirected.  The variable "c" contains the
1106  * first character of the redirection operator.
1107  */
1108
1109 parseredir: {
1110         char fd = *out;
1111         union node *np;
1112
1113         np = (union node *)stalloc(sizeof (struct nfile));
1114         if (c == '>') {
1115                 np->nfile.fd = 1;
1116                 c = pgetc();
1117                 if (c == '>')
1118                         np->type = NAPPEND;
1119                 else if (c == '&')
1120                         np->type = NTOFD;
1121                 else if (c == '|')
1122                         np->type = NCLOBBER;
1123                 else {
1124                         np->type = NTO;
1125                         pungetc();
1126                 }
1127         } else {        /* c == '<' */
1128                 np->nfile.fd = 0;
1129                 c = pgetc();
1130                 if (c == '<') {
1131                         if (sizeof (struct nfile) != sizeof (struct nhere)) {
1132                                 np = (union node *)stalloc(sizeof (struct nhere));
1133                                 np->nfile.fd = 0;
1134                         }
1135                         np->type = NHERE;
1136                         heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
1137                         heredoc->here = np;
1138                         if ((c = pgetc()) == '-') {
1139                                 heredoc->striptabs = 1;
1140                         } else {
1141                                 heredoc->striptabs = 0;
1142                                 pungetc();
1143                         }
1144                 } else if (c == '&')
1145                         np->type = NFROMFD;
1146                 else if (c == '>')
1147                         np->type = NFROMTO;
1148                 else {
1149                         np->type = NFROM;
1150                         pungetc();
1151                 }
1152         }
1153         if (fd != '\0')
1154                 np->nfile.fd = digit_val(fd);
1155         redirnode = np;
1156         goto parseredir_return;
1157 }
1158
1159
1160 /*
1161  * Parse a substitution.  At this point, we have read the dollar sign
1162  * and nothing else.
1163  */
1164
1165 parsesub: {
1166         char buf[10];
1167         int subtype;
1168         int typeloc;
1169         int flags;
1170         char *p;
1171         static const char types[] = "}-+?=";
1172         int bracketed_name = 0; /* used to handle ${[0-9]*} variables */
1173         int i;
1174         int linno;
1175         int length;
1176
1177         c = pgetc();
1178         if (c != '(' && c != '{' && (is_eof(c) || !is_name(c)) &&
1179             !is_special(c)) {
1180                 USTPUTC('$', out);
1181                 pungetc();
1182         } else if (c == '(') {  /* $(command) or $((arith)) */
1183                 if (pgetc() == '(') {
1184                         PARSEARITH();
1185                 } else {
1186                         pungetc();
1187                         PARSEBACKQNEW();
1188                 }
1189         } else {
1190                 USTPUTC(CTLVAR, out);
1191                 typeloc = out - stackblock();
1192                 USTPUTC(VSNORMAL, out);
1193                 subtype = VSNORMAL;
1194                 flags = 0;
1195                 if (c == '{') {
1196                         bracketed_name = 1;
1197                         c = pgetc();
1198                         if (c == '#') {
1199                                 if ((c = pgetc()) == '}')
1200                                         c = '#';
1201                                 else
1202                                         subtype = VSLENGTH;
1203                         }
1204                         else
1205                                 subtype = 0;
1206                 }
1207                 if (!is_eof(c) && is_name(c)) {
1208                         length = 0;
1209                         do {
1210                                 STPUTC(c, out);
1211                                 c = pgetc();
1212                                 length++;
1213                         } while (!is_eof(c) && is_in_name(c));
1214                         if (length == 6 &&
1215                             strncmp(out - length, "LINENO", length) == 0) {
1216                                 /* Replace the variable name with the
1217                                  * current line number. */
1218                                 linno = plinno;
1219                                 if (funclinno != 0)
1220                                         linno -= funclinno - 1;
1221                                 snprintf(buf, sizeof(buf), "%d", linno);
1222                                 STADJUST(-6, out);
1223                                 for (i = 0; buf[i] != '\0'; i++)
1224                                         STPUTC(buf[i], out);
1225                                 flags |= VSLINENO;
1226                         }
1227                 } else if (is_digit(c)) {
1228                         if (bracketed_name) {
1229                                 do {
1230                                         STPUTC(c, out);
1231                                         c = pgetc();
1232                                 } while (is_digit(c));
1233                         } else {
1234                                 STPUTC(c, out);
1235                                 c = pgetc();
1236                         }
1237                 } else {
1238                         if (! is_special(c)) {
1239                                 subtype = VSERROR;
1240                                 if (c == '}')
1241                                         pungetc();
1242                                 else
1243                                         USTPUTC(c, out);
1244                         } else {
1245                                 USTPUTC(c, out);
1246                                 c = pgetc();
1247                         }
1248                 }
1249                 if (subtype == 0) {
1250                         switch (c) {
1251                         case ':':
1252                                 flags |= VSNUL;
1253                                 c = pgetc();
1254                                 /*FALLTHROUGH*/
1255                         default:
1256                                 p = strchr(types, c);
1257                                 if (p == NULL) {
1258                                         if (flags == VSNUL)
1259                                                 STPUTC(':', out);
1260                                         STPUTC(c, out);
1261                                         subtype = VSERROR;
1262                                 } else
1263                                         subtype = p - types + VSNORMAL;
1264                                 break;
1265                         case '%':
1266                         case '#':
1267                                 {
1268                                         int cc = c;
1269                                         subtype = c == '#' ? VSTRIMLEFT :
1270                                                              VSTRIMRIGHT;
1271                                         c = pgetc();
1272                                         if (c == cc)
1273                                                 subtype++;
1274                                         else
1275                                                 pungetc();
1276                                         break;
1277                                 }
1278                         }
1279                 } else if (subtype != VSERROR) {
1280                         pungetc();
1281                 }
1282                 STPUTC('=', out);
1283                 if (subtype != VSLENGTH && (dblquote || arinest))
1284                         flags |= VSQUOTE;
1285                 *(stackblock() + typeloc) = subtype | flags;
1286                 if (subtype != VSNORMAL)
1287                         varnest++;
1288         }
1289         goto parsesub_return;
1290 }
1291
1292
1293 /*
1294  * Called to parse command substitutions.  Newstyle is set if the command
1295  * is enclosed inside $(...); nlpp is a pointer to the head of the linked
1296  * list of commands (passed by reference), and savelen is the number of
1297  * characters on the top of the stack which must be preserved.
1298  */
1299
1300 parsebackq: {
1301         struct nodelist **nlpp;
1302         int savepbq;
1303         union node *n;
1304         char *volatile str;
1305         struct jmploc jmploc;
1306         struct jmploc *volatile savehandler;
1307         int savelen;
1308         volatile int saveprompt;
1309
1310         savepbq = parsebackquote;
1311         if (setjmp(jmploc.loc)) {
1312                 if (str)
1313                         ckfree(str);
1314                 parsebackquote = 0;
1315                 handler = savehandler;
1316                 longjmp(handler->loc, 1);
1317         }
1318         INTOFF;
1319         str = NULL;
1320         savelen = out - stackblock();
1321         if (savelen > 0) {
1322                 str = ckmalloc(savelen);
1323                 memcpy(str, stackblock(), savelen);
1324         }
1325         savehandler = handler;
1326         handler = &jmploc;
1327         INTON;
1328         if (oldstyle) {
1329                 /* We must read until the closing backquote, giving special
1330                    treatment to some slashes, and then push the string and
1331                    reread it as input, interpreting it normally.  */
1332                 char *pout;
1333                 int pc;
1334                 int psavelen;
1335                 char *pstr;
1336
1337
1338                 STARTSTACKSTR(pout);
1339                 for (;;) {
1340                         if (needprompt) {
1341                                 setprompt(2);
1342                                 needprompt = 0;
1343                         }
1344                         switch (pc = pgetc()) {
1345                         case '`':
1346                                 goto done;
1347
1348                         case '\\':
1349                                 if ((pc = pgetc()) == '\n') {
1350                                         plinno++;
1351                                         if (doprompt)
1352                                                 setprompt(2);
1353                                         else
1354                                                 setprompt(0);
1355                                         /*
1356                                          * If eating a newline, avoid putting
1357                                          * the newline into the new character
1358                                          * stream (via the STPUTC after the
1359                                          * switch).
1360                                          */
1361                                         continue;
1362                                 }
1363                                 if (pc != '\\' && pc != '`' && pc != '$'
1364                                     && (!dblquote || pc != '"'))
1365                                         STPUTC('\\', pout);
1366                                 break;
1367
1368                         case '\n':
1369                                 plinno++;
1370                                 needprompt = doprompt;
1371                                 break;
1372
1373                         case PEOF:
1374                                 startlinno = plinno;
1375                                 synerror("EOF in backquote substitution");
1376                                 break;
1377
1378                         default:
1379                                 break;
1380                         }
1381                         STPUTC(pc, pout);
1382                 }
1383 done:
1384                 STPUTC('\0', pout);
1385                 psavelen = pout - stackblock();
1386                 if (psavelen > 0) {
1387                         pstr = ckmalloc(psavelen);
1388                         memcpy(pstr, stackblock(), psavelen);
1389                         setinputstring(pstr, 1);
1390                 }
1391         }
1392         nlpp = &bqlist;
1393         while (*nlpp)
1394                 nlpp = &(*nlpp)->next;
1395         *nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
1396         (*nlpp)->next = NULL;
1397         parsebackquote = oldstyle;
1398
1399         if (oldstyle) {
1400                 saveprompt = doprompt;
1401                 doprompt = 0;
1402         }
1403
1404         n = list(0);
1405
1406         if (oldstyle)
1407                 doprompt = saveprompt;
1408         else {
1409                 if (readtoken() != TRP)
1410                         synexpect(TRP);
1411         }
1412
1413         (*nlpp)->n = n;
1414         if (oldstyle) {
1415                 /*
1416                  * Start reading from old file again, ignoring any pushed back
1417                  * tokens left from the backquote parsing
1418                  */
1419                 popfile();
1420                 tokpushback = 0;
1421         }
1422         while (stackblocksize() <= savelen)
1423                 growstackblock();
1424         STARTSTACKSTR(out);
1425         if (str) {
1426                 memcpy(out, str, savelen);
1427                 STADJUST(savelen, out);
1428                 INTOFF;
1429                 ckfree(str);
1430                 str = NULL;
1431                 INTON;
1432         }
1433         parsebackquote = savepbq;
1434         handler = savehandler;
1435         if (arinest || dblquote)
1436                 USTPUTC(CTLBACKQ | CTLQUOTE, out);
1437         else
1438                 USTPUTC(CTLBACKQ, out);
1439         if (oldstyle)
1440                 goto parsebackq_oldreturn;
1441         else
1442                 goto parsebackq_newreturn;
1443 }
1444
1445 /*
1446  * Parse an arithmetic expansion (indicate start of one and set state)
1447  */
1448 parsearith: {
1449
1450         if (++arinest == 1) {
1451                 prevsyntax = syntax;
1452                 syntax = ARISYNTAX;
1453                 USTPUTC(CTLARI, out);
1454                 if (dblquote)
1455                         USTPUTC('"',out);
1456                 else
1457                         USTPUTC(' ',out);
1458         } else {
1459                 /*
1460                  * we collapse embedded arithmetic expansion to
1461                  * parenthesis, which should be equivalent
1462                  */
1463                 USTPUTC('(', out);
1464         }
1465         goto parsearith_return;
1466 }
1467
1468 } /* end of readtoken */
1469
1470
1471
1472 #ifdef mkinit
1473 RESET {
1474         tokpushback = 0;
1475         checkkwd = 0;
1476 }
1477 #endif
1478
1479 /*
1480  * Returns true if the text contains nothing to expand (no dollar signs
1481  * or backquotes).
1482  */
1483
1484 STATIC int
1485 noexpand(char *text)
1486 {
1487         char *p;
1488         char c;
1489
1490         p = text;
1491         while ((c = *p++) != '\0') {
1492                 if ( c == CTLQUOTEMARK)
1493                         continue;
1494                 if (c == CTLESC)
1495                         p++;
1496                 else if (BASESYNTAX[(int)c] == CCTL)
1497                         return 0;
1498         }
1499         return 1;
1500 }
1501
1502
1503 /*
1504  * Return true if the argument is a legal variable name (a letter or
1505  * underscore followed by zero or more letters, underscores, and digits).
1506  */
1507
1508 int
1509 goodname(char *name)
1510 {
1511         char *p;
1512
1513         p = name;
1514         if (! is_name(*p))
1515                 return 0;
1516         while (*++p) {
1517                 if (! is_in_name(*p))
1518                         return 0;
1519         }
1520         return 1;
1521 }
1522
1523
1524 /*
1525  * Called when an unexpected token is read during the parse.  The argument
1526  * is the token that is expected, or -1 if more than one type of token can
1527  * occur at this point.
1528  */
1529
1530 STATIC void
1531 synexpect(int token)
1532 {
1533         char msg[64];
1534
1535         if (token >= 0) {
1536                 fmtstr(msg, 64, "%s unexpected (expecting %s)",
1537                         tokname[lasttoken], tokname[token]);
1538         } else {
1539                 fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
1540         }
1541         synerror(msg);
1542 }
1543
1544
1545 STATIC void
1546 synerror(const char *msg)
1547 {
1548         if (commandname)
1549                 outfmt(&errout, "%s: %d: ", commandname, startlinno);
1550         outfmt(&errout, "Syntax error: %s\n", msg);
1551         error(NULL);
1552 }
1553
1554 STATIC void
1555 setprompt(int which)
1556 {
1557         whichprompt = which;
1558
1559 #ifndef NO_HISTORY
1560         if (!el)
1561 #endif
1562                 out2str(getprompt(NULL));
1563 }
1564
1565 /*
1566  * called by editline -- any expansions to the prompt
1567  *    should be added here.
1568  */
1569 const char *
1570 getprompt(void *unused __unused)
1571 {
1572         static char ps[PROMPTLEN];
1573         const char *fmt;
1574         int i, j, trim;
1575
1576         /*
1577          * Select prompt format.
1578          */
1579         switch (whichprompt) {
1580         case 0:
1581                 fmt = "";
1582                 break;
1583         case 1:
1584                 fmt = ps1val();
1585                 break;
1586         case 2:
1587                 fmt = ps2val();
1588                 break;
1589         default:
1590                 return "<internal prompt error>";
1591         }
1592
1593         /*
1594          * Format prompt string.
1595          */
1596         for (i = 0; (i < 127) && (*fmt != '\0'); i++, fmt++)
1597                 if (*fmt == '\\')
1598                         switch (*++fmt) {
1599
1600                                 /*
1601                                  * Hostname.
1602                                  *
1603                                  * \h specifies just the local hostname,
1604                                  * \H specifies fully-qualified hostname.
1605                                  */
1606                         case 'h':
1607                         case 'H':
1608                                 ps[i] = '\0';
1609                                 gethostname(&ps[i], PROMPTLEN - i);
1610                                 /* Skip to end of hostname. */
1611                                 trim = (*fmt == 'h') ? '.' : '\0';
1612                                 while ((ps[i+1] != '\0') && (ps[i+1] != trim))
1613                                         i++;
1614                                 break;
1615
1616                                 /*
1617                                  * Working directory.
1618                                  *
1619                                  * \W specifies just the final component,
1620                                  * \w specifies the entire path.
1621                                  */
1622                         case 'W':
1623                         case 'w':
1624                                 ps[i] = '\0';
1625                                 getcwd(&ps[i], PROMPTLEN - i);
1626                                 if (*fmt == 'W') {
1627                                         /* Final path component only. */
1628                                         trim = 1;
1629                                         for (j = i; ps[j] != '\0'; j++)
1630                                           if (ps[j] == '/')
1631                                                 trim = j + 1;
1632                                         memmove(&ps[i], &ps[trim],
1633                                             j - trim + 1);
1634                                 }
1635                                 /* Skip to end of path. */
1636                                 while (ps[i + 1] != '\0')
1637                                         i++;
1638                                 break;
1639
1640                                 /*
1641                                  * Superuser status.
1642                                  *
1643                                  * '$' for normal users, '#' for root.
1644                                  */
1645                         case '$':
1646                                 ps[i] = (geteuid() != 0) ? '$' : '#';
1647                                 break;
1648
1649                                 /*
1650                                  * A literal \.
1651                                  */
1652                         case '\\':
1653                                 ps[i] = '\\';
1654                                 break;
1655
1656                                 /*
1657                                  * Emit unrecognized formats verbatim.
1658                                  */
1659                         default:
1660                                 ps[i++] = '\\';
1661                                 ps[i] = *fmt;
1662                                 break;
1663                         }
1664                 else
1665                         ps[i] = *fmt;
1666         ps[i] = '\0';
1667         return (ps);
1668 }