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 1.110 2011/05/08 17:40:10 jilles Exp $
  38  */
  39
  40 #include <stdio.h>
  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 #include "exec.h"       /* to check for special builtins */
  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 of checkkwd variable */
  72 #define CHKALIAS        0x1
  73 #define CHKKWD          0x2
  74 #define CHKNL           0x4
  75
  76 /* values returned by readtoken */
  77 #include "token.h"
  78
  79
  80
  81 struct heredoc {
  82         struct heredoc *next;   /* next here document in list */
  83         union node *here;               /* redirection node */
  84         char *eofmark;          /* string indicating end of input */
  85         int striptabs;          /* if set, strip leading tabs */
  86 };
  87
  88 struct parser_temp {
  89         struct parser_temp *next;
  90         void *data;
  91 };
  92
  93
  94 static struct heredoc *heredoclist;     /* list of here documents to read */
  95 static int doprompt;            /* if set, prompt the user */
  96 static int needprompt;          /* true if interactive and at start of line */
  97 static int lasttoken;           /* last token read */
  98 MKINIT int tokpushback;         /* last token pushed back */
  99 static char *wordtext;          /* text of last word returned by readtoken */
 100 MKINIT int checkkwd;            /* 1 == check for kwds, 2 == also eat newlines */
 101 static struct nodelist *backquotelist;
 102 static union node *redirnode;
 103 static struct heredoc *heredoc;
 104 static int quoteflag;           /* set if (part of) last token was quoted */
 105 static int startlinno;          /* line # where last token started */
 106 static int funclinno;           /* line # where the current function started */
 107 static struct parser_temp *parser_temp;
 108
 109
 110 static union node *list(int, int);
 111 static union node *andor(void);
 112 static union node *pipeline(void);
 113 static union node *command(void);
 114 static union node *simplecmd(union node **, union node *);
 115 static union node *makename(void);
 116 static void parsefname(void);
 117 static void parseheredoc(void);
 118 static int peektoken(void);
 119 static int readtoken(void);
 120 static int xxreadtoken(void);
 121 static int readtoken1(int, char const *, char *, int);
 122 static int noexpand(char *);
 123 static void synexpect(int) __dead2;
 124 static void synerror(const char *) __dead2;
 125 static void setprompt(int);
 126
 127
 128 static void *
 129 parser_temp_alloc(size_t len)
 130 {
 131         struct parser_temp *t;
 132
 133         INTOFF;
 134         t = ckmalloc(sizeof(*t));
 135         t->data = NULL;
 136         t->next = parser_temp;
 137         parser_temp = t;
 138         t->data = ckmalloc(len);
 139         INTON;
 140         return t->data;
 141 }
 142
 143
 144 static void *
 145 parser_temp_realloc(void *ptr, size_t len)
 146 {
 147         struct parser_temp *t;
 148
 149         INTOFF;
 150         t = parser_temp;
 151         if (ptr != t->data)
 152                 error("bug: parser_temp_realloc misused");
 153         t->data = ckrealloc(t->data, len);
 154         INTON;
 155         return t->data;
 156 }
 157
 158
 159 static void
 160 parser_temp_free_upto(void *ptr)
 161 {
 162         struct parser_temp *t;
 163         int done = 0;
 164
 165         INTOFF;
 166         while (parser_temp != NULL && !done) {
 167                 t = parser_temp;
 168                 parser_temp = t->next;
 169                 done = t->data == ptr;
 170                 ckfree(t->data);
 171                 ckfree(t);
 172         }
 173         INTON;
 174         if (!done)
 175                 error("bug: parser_temp_free_upto misused");
 176 }
 177
 178
 179 static void
 180 parser_temp_free_all(void)
 181 {
 182         struct parser_temp *t;
 183
 184         INTOFF;
 185         while (parser_temp != NULL) {
 186                 t = parser_temp;
 187                 parser_temp = t->next;
 188                 ckfree(t->data);
 189                 ckfree(t);
 190         }
 191         INTON;
 192 }
 193
 194
 195 /*
 196  * Read and parse a command.  Returns NEOF on end of file.  (NULL is a
 197  * valid parse tree indicating a blank line.)
 198  */
 199
 200 union node *
 201 parsecmd(int interact)
 202 {
 203         int t;
 204
 205         /* This assumes the parser is not re-entered,
 206          * which could happen if we add command substitution on PS1/PS2.
 207          */
 208         parser_temp_free_all();
 209         heredoclist = NULL;
 210
 211         tokpushback = 0;
 212         doprompt = interact;
 213         if (doprompt)
 214                 setprompt(1);
 215         else
 216                 setprompt(0);
 217         needprompt = 0;
 218         t = readtoken();
 219         if (t == TEOF)
 220                 return NEOF;
 221         if (t == TNL)
 222                 return NULL;
 223         tokpushback++;
 224         return list(1, 1);
 225 }
 226
 227
 228 static union node *
 229 list(int nlflag, int erflag)
 230 {
 231         union node *ntop, *n1, *n2, *n3;
 232         int tok;
 233
 234         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 235         if (!nlflag && !erflag && tokendlist[peektoken()])
 236                 return NULL;
 237         ntop = n1 = NULL;
 238         for (;;) {
 239                 n2 = andor();
 240                 tok = readtoken();
 241                 if (tok == TBACKGND) {
 242                         if (n2->type == NCMD || n2->type == NPIPE) {
 243                                 n2->ncmd.backgnd = 1;
 244                         } else if (n2->type == NREDIR) {
 245                                 n2->type = NBACKGND;
 246                         } else {
 247                                 n3 = (union node *)stalloc(sizeof (struct nredir));
 248                                 n3->type = NBACKGND;
 249                                 n3->nredir.n = n2;
 250                                 n3->nredir.redirect = NULL;
 251                                 n2 = n3;
 252                         }
 253                 }
 254                 if (ntop == NULL)
 255                         ntop = n2;
 256                 else if (n1 == NULL) {
 257                         n1 = (union node *)stalloc(sizeof (struct nbinary));
 258                         n1->type = NSEMI;
 259                         n1->nbinary.ch1 = ntop;
 260                         n1->nbinary.ch2 = n2;
 261                         ntop = n1;
 262                 }
 263                 else {
 264                         n3 = (union node *)stalloc(sizeof (struct nbinary));
 265                         n3->type = NSEMI;
 266                         n3->nbinary.ch1 = n1->nbinary.ch2;
 267                         n3->nbinary.ch2 = n2;
 268                         n1->nbinary.ch2 = n3;
 269                         n1 = n3;
 270                 }
 271                 switch (tok) {
 272                 case TBACKGND:
 273                 case TSEMI:
 274                         tok = readtoken();
 275                         /* FALLTHROUGH */
 276                 case TNL:
 277                         if (tok == TNL) {
 278                                 parseheredoc();
 279                                 if (nlflag)
 280                                         return ntop;
 281                         } else if (tok == TEOF && nlflag) {
 282                                 parseheredoc();
 283                                 return ntop;
 284                         } else {
 285                                 tokpushback++;
 286                         }
 287                         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 288                         if (!nlflag && !erflag && tokendlist[peektoken()])
 289                                 return ntop;
 290                         break;
 291                 case TEOF:
 292                         if (heredoclist)
 293                                 parseheredoc();
 294                         else
 295                                 pungetc();              /* push back EOF on input */
 296                         return ntop;
 297                 default:
 298                         if (nlflag || erflag)
 299                                 synexpect(-1);
 300                         tokpushback++;
 301                         return ntop;
 302                 }
 303         }
 304 }
 305
 306
 307
 308 static union node *
 309 andor(void)
 310 {
 311         union node *n1, *n2, *n3;
 312         int t;
 313
 314         n1 = pipeline();
 315         for (;;) {
 316                 if ((t = readtoken()) == TAND) {
 317                         t = NAND;
 318                 } else if (t == TOR) {
 319                         t = NOR;
 320                 } else {
 321                         tokpushback++;
 322                         return n1;
 323                 }
 324                 n2 = pipeline();
 325                 n3 = (union node *)stalloc(sizeof (struct nbinary));
 326                 n3->type = t;
 327                 n3->nbinary.ch1 = n1;
 328                 n3->nbinary.ch2 = n2;
 329                 n1 = n3;
 330         }
 331 }
 332
 333
 334
 335 static union node *
 336 pipeline(void)
 337 {
 338         union node *n1, *n2, *pipenode;
 339         struct nodelist *lp, *prev;
 340         int negate, t;
 341
 342         negate = 0;
 343         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 344         TRACE(("pipeline: entered\n"));
 345         while (readtoken() == TNOT)
 346                 negate = !negate;
 347         tokpushback++;
 348         n1 = command();
 349         if (readtoken() == TPIPE) {
 350                 pipenode = (union node *)stalloc(sizeof (struct npipe));
 351                 pipenode->type = NPIPE;
 352                 pipenode->npipe.backgnd = 0;
 353                 lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 354                 pipenode->npipe.cmdlist = lp;
 355                 lp->n = n1;
 356                 do {
 357                         prev = lp;
 358                         lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 359                         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 360                         t = readtoken();
 361                         tokpushback++;
 362                         if (t == TNOT)
 363                                 lp->n = pipeline();
 364                         else
 365                                 lp->n = command();
 366                         prev->next = lp;
 367                 } while (readtoken() == TPIPE);
 368                 lp->next = NULL;
 369                 n1 = pipenode;
 370         }
 371         tokpushback++;
 372         if (negate) {
 373                 n2 = (union node *)stalloc(sizeof (struct nnot));
 374                 n2->type = NNOT;
 375                 n2->nnot.com = n1;
 376                 return n2;
 377         } else
 378                 return n1;
 379 }
 380
 381
 382
 383 static union node *
 384 command(void)
 385 {
 386         union node *n1, *n2;
 387         union node *ap, **app;
 388         union node *cp, **cpp;
 389         union node *redir, **rpp;
 390         int t;
 391         int is_subshell;
 392
 393         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 394         is_subshell = 0;
 395         redir = NULL;
 396         n1 = NULL;
 397         rpp = &redir;
 398
 399         /* Check for redirection which may precede command */
 400         while (readtoken() == TREDIR) {
 401                 *rpp = n2 = redirnode;
 402                 rpp = &n2->nfile.next;
 403                 parsefname();
 404         }
 405         tokpushback++;
 406
 407         switch (readtoken()) {
 408         case TIF:
 409                 n1 = (union node *)stalloc(sizeof (struct nif));
 410                 n1->type = NIF;
 411                 if ((n1->nif.test = list(0, 0)) == NULL)
 412                         synexpect(-1);
 413                 if (readtoken() != TTHEN)
 414                         synexpect(TTHEN);
 415                 n1->nif.ifpart = list(0, 0);
 416                 n2 = n1;
 417                 while (readtoken() == TELIF) {
 418                         n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
 419                         n2 = n2->nif.elsepart;
 420                         n2->type = NIF;
 421                         if ((n2->nif.test = list(0, 0)) == NULL)
 422                                 synexpect(-1);
 423                         if (readtoken() != TTHEN)
 424                                 synexpect(TTHEN);
 425                         n2->nif.ifpart = list(0, 0);
 426                 }
 427                 if (lasttoken == TELSE)
 428                         n2->nif.elsepart = list(0, 0);
 429                 else {
 430                         n2->nif.elsepart = NULL;
 431                         tokpushback++;
 432                 }
 433                 if (readtoken() != TFI)
 434                         synexpect(TFI);
 435                 checkkwd = CHKKWD | CHKALIAS;
 436                 break;
 437         case TWHILE:
 438         case TUNTIL: {
 439                 int got;
 440                 n1 = (union node *)stalloc(sizeof (struct nbinary));
 441                 n1->type = (lasttoken == TWHILE)? NWHILE : NUNTIL;
 442                 if ((n1->nbinary.ch1 = list(0, 0)) == NULL)
 443                         synexpect(-1);
 444                 if ((got=readtoken()) != TDO) {
 445 TRACE(("expecting DO got %s %s\n", tokname[got], got == TWORD ? wordtext : ""));
 446                         synexpect(TDO);
 447                 }
 448                 n1->nbinary.ch2 = list(0, 0);
 449                 if (readtoken() != TDONE)
 450                         synexpect(TDONE);
 451                 checkkwd = CHKKWD | CHKALIAS;
 452                 break;
 453         }
 454         case TFOR:
 455                 if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
 456                         synerror("Bad for loop variable");
 457                 n1 = (union node *)stalloc(sizeof (struct nfor));
 458                 n1->type = NFOR;
 459                 n1->nfor.var = wordtext;
 460                 while (readtoken() == TNL)
 461                         ;
 462                 if (lasttoken == TWORD && ! quoteflag && equal(wordtext, "in")) {
 463                         app = &ap;
 464                         while (readtoken() == TWORD) {
 465                                 n2 = (union node *)stalloc(sizeof (struct narg));
 466                                 n2->type = NARG;
 467                                 n2->narg.text = wordtext;
 468                                 n2->narg.backquote = backquotelist;
 469                                 *app = n2;
 470                                 app = &n2->narg.next;
 471                         }
 472                         *app = NULL;
 473                         n1->nfor.args = ap;
 474                         if (lasttoken != TNL && lasttoken != TSEMI)
 475                                 synexpect(-1);
 476                 } else {
 477                         static char argvars[5] = {
 478                                 CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'
 479                         };
 480                         n2 = (union node *)stalloc(sizeof (struct narg));
 481                         n2->type = NARG;
 482                         n2->narg.text = argvars;
 483                         n2->narg.backquote = NULL;
 484                         n2->narg.next = NULL;
 485                         n1->nfor.args = n2;
 486                         /*
 487                          * Newline or semicolon here is optional (but note
 488                          * that the original Bourne shell only allowed NL).
 489                          */
 490                         if (lasttoken != TNL && lasttoken != TSEMI)
 491                                 tokpushback++;
 492                 }
 493                 checkkwd = CHKNL | CHKKWD | CHKALIAS;
 494                 if ((t = readtoken()) == TDO)
 495                         t = TDONE;
 496                 else if (t == TBEGIN)
 497                         t = TEND;
 498                 else
 499                         synexpect(-1);
 500                 n1->nfor.body = list(0, 0);
 501                 if (readtoken() != t)
 502                         synexpect(t);
 503                 checkkwd = CHKKWD | CHKALIAS;
 504                 break;
 505         case TCASE:
 506                 n1 = (union node *)stalloc(sizeof (struct ncase));
 507                 n1->type = NCASE;
 508                 if (readtoken() != TWORD)
 509                         synexpect(TWORD);
 510                 n1->ncase.expr = n2 = (union node *)stalloc(sizeof (struct narg));
 511                 n2->type = NARG;
 512                 n2->narg.text = wordtext;
 513                 n2->narg.backquote = backquotelist;
 514                 n2->narg.next = NULL;
 515                 while (readtoken() == TNL);
 516                 if (lasttoken != TWORD || ! equal(wordtext, "in"))
 517                         synerror("expecting \"in\"");
 518                 cpp = &n1->ncase.cases;
 519                 checkkwd = CHKNL | CHKKWD, readtoken();
 520                 while (lasttoken != TESAC) {
 521                         *cpp = cp = (union node *)stalloc(sizeof (struct nclist));
 522                         cp->type = NCLIST;
 523                         app = &cp->nclist.pattern;
 524                         if (lasttoken == TLP)
 525                                 readtoken();
 526                         for (;;) {
 527                                 *app = ap = (union node *)stalloc(sizeof (struct narg));
 528                                 ap->type = NARG;
 529                                 ap->narg.text = wordtext;
 530                                 ap->narg.backquote = backquotelist;
 531                                 checkkwd = CHKNL | CHKKWD;
 532                                 if (readtoken() != TPIPE)
 533                                         break;
 534                                 app = &ap->narg.next;
 535                                 readtoken();
 536                         }
 537                         ap->narg.next = NULL;
 538                         if (lasttoken != TRP)
 539                                 synexpect(TRP);
 540                         cp->nclist.body = list(0, 0);
 541
 542                         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 543                         if ((t = readtoken()) != TESAC) {
 544                                 if (t != TENDCASE)
 545                                         synexpect(TENDCASE);
 546                                 else
 547                                         checkkwd = CHKNL | CHKKWD, readtoken();
 548                         }
 549                         cpp = &cp->nclist.next;
 550                 }
 551                 *cpp = NULL;
 552                 checkkwd = CHKKWD | CHKALIAS;
 553                 break;
 554         case TLP:
 555                 n1 = (union node *)stalloc(sizeof (struct nredir));
 556                 n1->type = NSUBSHELL;
 557                 n1->nredir.n = list(0, 0);
 558                 n1->nredir.redirect = NULL;
 559                 if (readtoken() != TRP)
 560                         synexpect(TRP);
 561                 checkkwd = CHKKWD | CHKALIAS;
 562                 is_subshell = 1;
 563                 break;
 564         case TBEGIN:
 565                 n1 = list(0, 0);
 566                 if (readtoken() != TEND)
 567                         synexpect(TEND);
 568                 checkkwd = CHKKWD | CHKALIAS;
 569                 break;
 570         /* Handle an empty command like other simple commands.  */
 571         case TBACKGND:
 572         case TSEMI:
 573         case TAND:
 574         case TOR:
 575                 /*
 576                  * An empty command before a ; doesn't make much sense, and
 577                  * should certainly be disallowed in the case of `if ;'.
 578                  */
 579                 if (!redir)
 580                         synexpect(-1);
 581         case TNL:
 582         case TEOF:
 583         case TWORD:
 584         case TRP:
 585                 tokpushback++;
 586                 n1 = simplecmd(rpp, redir);
 587                 return n1;
 588         default:
 589                 synexpect(-1);
 590         }
 591
 592         /* Now check for redirection which may follow command */
 593         while (readtoken() == TREDIR) {
 594                 *rpp = n2 = redirnode;
 595                 rpp = &n2->nfile.next;
 596                 parsefname();
 597         }
 598         tokpushback++;
 599         *rpp = NULL;
 600         if (redir) {
 601                 if (!is_subshell) {
 602                         n2 = (union node *)stalloc(sizeof (struct nredir));
 603                         n2->type = NREDIR;
 604                         n2->nredir.n = n1;
 605                         n1 = n2;
 606                 }
 607                 n1->nredir.redirect = redir;
 608         }
 609
 610         return n1;
 611 }
 612
 613
 614 static union node *
 615 simplecmd(union node **rpp, union node *redir)
 616 {
 617         union node *args, **app;
 618         union node **orig_rpp = rpp;
 619         union node *n = NULL;
 620         int special;
 621
 622         /* If we don't have any redirections already, then we must reset */
 623         /* rpp to be the address of the local redir variable.  */
 624         if (redir == 0)
 625                 rpp = &redir;
 626
 627         args = NULL;
 628         app = &args;
 629         /*
 630          * We save the incoming value, because we need this for shell
 631          * functions.  There can not be a redirect or an argument between
 632          * the function name and the open parenthesis.
 633          */
 634         orig_rpp = rpp;
 635
 636         for (;;) {
 637                 if (readtoken() == TWORD) {
 638                         n = (union node *)stalloc(sizeof (struct narg));
 639                         n->type = NARG;
 640                         n->narg.text = wordtext;
 641                         n->narg.backquote = backquotelist;
 642                         *app = n;
 643                         app = &n->narg.next;
 644                 } else if (lasttoken == TREDIR) {
 645                         *rpp = n = redirnode;
 646                         rpp = &n->nfile.next;
 647                         parsefname();   /* read name of redirection file */
 648                 } else if (lasttoken == TLP && app == &args->narg.next
 649                                             && rpp == orig_rpp) {
 650                         /* We have a function */
 651                         if (readtoken() != TRP)
 652                                 synexpect(TRP);
 653                         funclinno = plinno;
 654                         /*
 655                          * - Require plain text.
 656                          * - Functions with '/' cannot be called.
 657                          * - Reject name=().
 658                          * - Reject ksh extended glob patterns.
 659                          */
 660                         if (!noexpand(n->narg.text) || quoteflag ||
 661                             strchr(n->narg.text, '/') ||
 662                             strchr("!%*+-=?@}~",
 663                                 n->narg.text[strlen(n->narg.text) - 1]))
 664                                 synerror("Bad function name");
 665                         rmescapes(n->narg.text);
 666                         if (find_builtin(n->narg.text, &special) >= 0 &&
 667                             special)
 668                                 synerror("Cannot override a special builtin with a function");
 669                         n->type = NDEFUN;
 670                         n->narg.next = command();
 671                         funclinno = 0;
 672                         return n;
 673                 } else {
 674                         tokpushback++;
 675                         break;
 676                 }
 677         }
 678         *app = NULL;
 679         *rpp = NULL;
 680         n = (union node *)stalloc(sizeof (struct ncmd));
 681         n->type = NCMD;
 682         n->ncmd.backgnd = 0;
 683         n->ncmd.args = args;
 684         n->ncmd.redirect = redir;
 685         return n;
 686 }
 687
 688 static union node *
 689 makename(void)
 690 {
 691         union node *n;
 692
 693         n = (union node *)stalloc(sizeof (struct narg));
 694         n->type = NARG;
 695         n->narg.next = NULL;
 696         n->narg.text = wordtext;
 697         n->narg.backquote = backquotelist;
 698         return n;
 699 }
 700
 701 void
 702 fixredir(union node *n, const char *text, int err)
 703 {
 704         TRACE(("Fix redir %s %d\n", text, err));
 705         if (!err)
 706                 n->ndup.vname = NULL;
 707
 708         if (is_digit(text[0]) && text[1] == '\0')
 709                 n->ndup.dupfd = digit_val(text[0]);
 710         else if (text[0] == '-' && text[1] == '\0')
 711                 n->ndup.dupfd = -1;
 712         else {
 713
 714                 if (err)
 715                         synerror("Bad fd number");
 716                 else
 717                         n->ndup.vname = makename();
 718         }
 719 }
 720
 721
 722 static void
 723 parsefname(void)
 724 {
 725         union node *n = redirnode;
 726
 727         if (readtoken() != TWORD)
 728                 synexpect(-1);
 729         if (n->type == NHERE) {
 730                 struct heredoc *here = heredoc;
 731                 struct heredoc *p;
 732                 int i;
 733
 734                 if (quoteflag == 0)
 735                         n->type = NXHERE;
 736                 TRACE(("Here document %d\n", n->type));
 737                 if (here->striptabs) {
 738                         while (*wordtext == '\t')
 739                                 wordtext++;
 740                 }
 741                 if (! noexpand(wordtext) || (i = strlen(wordtext)) == 0 || i > EOFMARKLEN)
 742                         synerror("Illegal eof marker for << redirection");
 743                 rmescapes(wordtext);
 744                 here->eofmark = wordtext;
 745                 here->next = NULL;
 746                 if (heredoclist == NULL)
 747                         heredoclist = here;
 748                 else {
 749                         for (p = heredoclist ; p->next ; p = p->next);
 750                         p->next = here;
 751                 }
 752         } else if (n->type == NTOFD || n->type == NFROMFD) {
 753                 fixredir(n, wordtext, 0);
 754         } else {
 755                 n->nfile.fname = makename();
 756         }
 757 }
 758
 759
 760 /*
 761  * Input any here documents.
 762  */
 763
 764 static void
 765 parseheredoc(void)
 766 {
 767         struct heredoc *here;
 768         union node *n;
 769
 770         while (heredoclist) {
 771                 here = heredoclist;
 772                 heredoclist = here->next;
 773                 if (needprompt) {
 774                         setprompt(2);
 775                         needprompt = 0;
 776                 }
 777                 readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
 778                                 here->eofmark, here->striptabs);
 779                 n = (union node *)stalloc(sizeof (struct narg));
 780                 n->narg.type = NARG;
 781                 n->narg.next = NULL;
 782                 n->narg.text = wordtext;
 783                 n->narg.backquote = backquotelist;
 784                 here->here->nhere.doc = n;
 785         }
 786 }
 787
 788 static int
 789 peektoken(void)
 790 {
 791         int t;
 792
 793         t = readtoken();
 794         tokpushback++;
 795         return (t);
 796 }
 797
 798 static int
 799 readtoken(void)
 800 {
 801         int t;
 802         struct alias *ap;
 803 #ifdef DEBUG
 804         int alreadyseen = tokpushback;
 805 #endif
 806
 807         top:
 808         t = xxreadtoken();
 809
 810         /*
 811          * eat newlines
 812          */
 813         if (checkkwd & CHKNL) {
 814                 while (t == TNL) {
 815                         parseheredoc();
 816                         t = xxreadtoken();
 817                 }
 818         }
 819
 820         /*
 821          * check for keywords and aliases
 822          */
 823         if (t == TWORD && !quoteflag)
 824         {
 825                 const char * const *pp;
 826
 827                 if (checkkwd & CHKKWD)
 828                         for (pp = parsekwd; *pp; pp++) {
 829                                 if (**pp == *wordtext && equal(*pp, wordtext))
 830                                 {
 831                                         lasttoken = t = pp - parsekwd + KWDOFFSET;
 832                                         TRACE(("keyword %s recognized\n", tokname[t]));
 833                                         goto out;
 834                                 }
 835                         }
 836                 if (checkkwd & CHKALIAS &&
 837                     (ap = lookupalias(wordtext, 1)) != NULL) {
 838                         pushstring(ap->val, strlen(ap->val), ap);
 839                         goto top;
 840                 }
 841         }
 842 out:
 843         if (t != TNOT)
 844                 checkkwd = 0;
 845
 846 #ifdef DEBUG
 847         if (!alreadyseen)
 848             TRACE(("token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 849         else
 850             TRACE(("reread token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 851 #endif
 852         return (t);
 853 }
 854
 855
 856 /*
 857  * Read the next input token.
 858  * If the token is a word, we set backquotelist to the list of cmds in
 859  *      backquotes.  We set quoteflag to true if any part of the word was
 860  *      quoted.
 861  * If the token is TREDIR, then we set redirnode to a structure containing
 862  *      the redirection.
 863  * In all cases, the variable startlinno is set to the number of the line
 864  *      on which the token starts.
 865  *
 866  * [Change comment:  here documents and internal procedures]
 867  * [Readtoken shouldn't have any arguments.  Perhaps we should make the
 868  *  word parsing code into a separate routine.  In this case, readtoken
 869  *  doesn't need to have any internal procedures, but parseword does.
 870  *  We could also make parseoperator in essence the main routine, and
 871  *  have parseword (readtoken1?) handle both words and redirection.]
 872  */
 873
 874 #define RETURN(token)   return lasttoken = token
 875
 876 static int
 877 xxreadtoken(void)
 878 {
 879         int c;
 880
 881         if (tokpushback) {
 882                 tokpushback = 0;
 883                 return lasttoken;
 884         }
 885         if (needprompt) {
 886                 setprompt(2);
 887                 needprompt = 0;
 888         }
 889         startlinno = plinno;
 890         for (;;) {      /* until token or start of word found */
 891                 c = pgetc_macro();
 892                 switch (c) {
 893                 case ' ': case '\t':
 894                         continue;
 895                 case '#':
 896                         while ((c = pgetc()) != '\n' && c != PEOF);
 897                         pungetc();
 898                         continue;
 899                 case '\\':
 900                         if (pgetc() == '\n') {
 901                                 startlinno = ++plinno;
 902                                 if (doprompt)
 903                                         setprompt(2);
 904                                 else
 905                                         setprompt(0);
 906                                 continue;
 907                         }
 908                         pungetc();
 909                         goto breakloop;
 910                 case '\n':
 911                         plinno++;
 912                         needprompt = doprompt;
 913                         RETURN(TNL);
 914                 case PEOF:
 915                         RETURN(TEOF);
 916                 case '&':
 917                         if (pgetc() == '&')
 918                                 RETURN(TAND);
 919                         pungetc();
 920                         RETURN(TBACKGND);
 921                 case '|':
 922                         if (pgetc() == '|')
 923                                 RETURN(TOR);
 924                         pungetc();
 925                         RETURN(TPIPE);
 926                 case ';':
 927                         if (pgetc() == ';')
 928                                 RETURN(TENDCASE);
 929                         pungetc();
 930                         RETURN(TSEMI);
 931                 case '(':
 932                         RETURN(TLP);
 933                 case ')':
 934                         RETURN(TRP);
 935                 default:
 936                         goto breakloop;
 937                 }
 938         }
 939 breakloop:
 940         return readtoken1(c, BASESYNTAX, NULL, 0);
 941 #undef RETURN
 942 }
 943
 944
 945 #define MAXNEST_STATIC 8
 946 struct tokenstate
 947 {
 948         const char *syntax; /* *SYNTAX */
 949         int parenlevel; /* levels of parentheses in arithmetic */
 950         enum tokenstate_category
 951         {
 952                 TSTATE_TOP,
 953                 TSTATE_VAR_OLD, /* ${var+-=?}, inherits dquotes */
 954                 TSTATE_VAR_NEW, /* other ${var...}, own dquote state */
 955                 TSTATE_ARITH
 956         } category;
 957 };
 958
 959
 960 /*
 961  * Called to parse command substitutions.
 962  */
 963
 964 static char *
 965 parsebackq(char *out, struct nodelist **pbqlist,
 966     int oldstyle, int dblquote, int quoted)
 967 {
 968         struct nodelist **nlpp;
 969         union node *n;
 970         char *volatile str;
 971         struct jmploc jmploc;
 972         struct jmploc *const savehandler = handler;
 973         int savelen;
 974         int saveprompt;
 975         const int bq_startlinno = plinno;
 976         char *volatile ostr = NULL;
 977         struct parsefile *const savetopfile = getcurrentfile();
 978         struct heredoc *const saveheredoclist = heredoclist;
 979         struct heredoc *here;
 980
 981         str = NULL;
 982         if (setjmp(jmploc.loc)) {
 983                 popfilesupto(savetopfile);
 984                 if (str)
 985                         ckfree(str);
 986                 if (ostr)
 987                         ckfree(ostr);
 988                 heredoclist = saveheredoclist;
 989                 handler = savehandler;
 990                 if (exception == EXERROR) {
 991                         startlinno = bq_startlinno;
 992                         synerror("Error in command substitution");
 993                 }
 994                 longjmp(handler->loc, 1);
 995         }
 996         INTOFF;
 997         savelen = out - stackblock();
 998         if (savelen > 0) {
 999                 str = ckmalloc(savelen);
1000                 memcpy(str, stackblock(), savelen);
1001         }
1002         handler = &jmploc;
1003         heredoclist = NULL;
1004         INTON;
1005         if (oldstyle) {
1006                 /*
1007                  * We must read until the closing backquote, giving special
1008                  * treatment to some slashes, and then push the string and
1009                  * reread it as input, interpreting it normally.
1010                  */
1011                 char *oout;
1012                 int c, olen;
1013
1014                 STARTSTACKSTR(oout);
1015                 for (;;) {
1016                         if (needprompt) {
1017                                 setprompt(2);
1018                                 needprompt = 0;
1019                         }
1020                         CHECKSTRSPACE(2, oout);
1021                         switch (c = pgetc()) {
1022                         case '`':
1023                                 goto done;
1024
1025                         case '\\':
1026                                 if ((c = pgetc()) == '\n') {
1027                                         plinno++;
1028                                         if (doprompt)
1029                                                 setprompt(2);
1030                                         else
1031                                                 setprompt(0);
1032                                         /*
1033                                          * If eating a newline, avoid putting
1034                                          * the newline into the new character
1035                                          * stream (via the USTPUTC after the
1036                                          * switch).
1037                                          */
1038                                         continue;
1039                                 }
1040                                 if (c != '\\' && c != '`' && c != '$'
1041                                     && (!dblquote || c != '"'))
1042                                         USTPUTC('\\', oout);
1043                                 break;
1044
1045                         case '\n':
1046                                 plinno++;
1047                                 needprompt = doprompt;
1048                                 break;
1049
1050                         case PEOF:
1051                                 startlinno = plinno;
1052                                 synerror("EOF in backquote substitution");
1053                                 break;
1054
1055                         default:
1056                                 break;
1057                         }
1058                         USTPUTC(c, oout);
1059                 }
1060 done:
1061                 USTPUTC('\0', oout);
1062                 olen = oout - stackblock();
1063                 INTOFF;
1064                 ostr = ckmalloc(olen);
1065                 memcpy(ostr, stackblock(), olen);
1066                 setinputstring(ostr, 1);
1067                 INTON;
1068         }
1069         nlpp = pbqlist;
1070         while (*nlpp)
1071                 nlpp = &(*nlpp)->next;
1072         *nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
1073         (*nlpp)->next = NULL;
1074
1075         if (oldstyle) {
1076                 saveprompt = doprompt;
1077                 doprompt = 0;
1078         }
1079
1080         n = list(0, oldstyle);
1081
1082         if (oldstyle)
1083                 doprompt = saveprompt;
1084         else {
1085                 if (readtoken() != TRP)
1086                         synexpect(TRP);
1087         }
1088
1089         (*nlpp)->n = n;
1090         if (oldstyle) {
1091                 /*
1092                  * Start reading from old file again, ignoring any pushed back
1093                  * tokens left from the backquote parsing
1094                  */
1095                 popfile();
1096                 tokpushback = 0;
1097         }
1098         STARTSTACKSTR(out);
1099         CHECKSTRSPACE(savelen + 1, out);
1100         INTOFF;
1101         if (str) {
1102                 memcpy(out, str, savelen);
1103                 STADJUST(savelen, out);
1104                 ckfree(str);
1105                 str = NULL;
1106         }
1107         if (ostr) {
1108                 ckfree(ostr);
1109                 ostr = NULL;
1110         }
1111         here = saveheredoclist;
1112         if (here != NULL) {
1113                 while (here->next != NULL)
1114                         here = here->next;
1115                 here->next = heredoclist;
1116                 heredoclist = saveheredoclist;
1117         }
1118         handler = savehandler;
1119         INTON;
1120         if (quoted)
1121                 USTPUTC(CTLBACKQ | CTLQUOTE, out);
1122         else
1123                 USTPUTC(CTLBACKQ, out);
1124         return out;
1125 }
1126
1127
1128 /*
1129  * Called to parse a backslash escape sequence inside $'...'.
1130  * The backslash has already been read.
1131  */
1132 static char *
1133 readcstyleesc(char *out)
1134 {
1135         int c, v, i, n;
1136
1137         c = pgetc();
1138         switch (c) {
1139         case '\0':
1140                 synerror("Unterminated quoted string");
1141         case '\n':
1142                 plinno++;
1143                 if (doprompt)
1144                         setprompt(2);
1145                 else
1146                         setprompt(0);
1147                 return out;
1148         case '\\':
1149         case '\'':
1150         case '"':
1151                 v = c;
1152                 break;
1153         case 'a': v = '\a'; break;
1154         case 'b': v = '\b'; break;
1155         case 'e': v = '\033'; break;
1156         case 'f': v = '\f'; break;
1157         case 'n': v = '\n'; break;
1158         case 'r': v = '\r'; break;
1159         case 't': v = '\t'; break;
1160         case 'v': v = '\v'; break;
1161         case 'x':
1162                   v = 0;
1163                   for (;;) {
1164                           c = pgetc();
1165                           if (c >= '0' && c <= '9')
1166                                   v = (v << 4) + c - '0';
1167                           else if (c >= 'A' && c <= 'F')
1168                                   v = (v << 4) + c - 'A' + 10;
1169                           else if (c >= 'a' && c <= 'f')
1170                                   v = (v << 4) + c - 'a' + 10;
1171                           else
1172                                   break;
1173                   }
1174                   pungetc();
1175                   break;
1176         case '0': case '1': case '2': case '3':
1177         case '4': case '5': case '6': case '7':
1178                   v = c - '0';
1179                   c = pgetc();
1180                   if (c >= '0' && c <= '7') {
1181                           v <<= 3;
1182                           v += c - '0';
1183                           c = pgetc();
1184                           if (c >= '0' && c <= '7') {
1185                                   v <<= 3;
1186                                   v += c - '0';
1187                           } else
1188                                   pungetc();
1189                   } else
1190                           pungetc();
1191                   break;
1192         case 'c':
1193                   c = pgetc();
1194                   if (c < 0x3f || c > 0x7a || c == 0x60)
1195                           synerror("Bad escape sequence");
1196                   if (c == '\\' && pgetc() != '\\')
1197                           synerror("Bad escape sequence");
1198                   if (c == '?')
1199                           v = 127;
1200                   else
1201                           v = c & 0x1f;
1202                   break;
1203         case 'u':
1204         case 'U':
1205                   n = c == 'U' ? 8 : 4;
1206                   v = 0;
1207                   for (i = 0; i < n; i++) {
1208                           c = pgetc();
1209                           if (c >= '0' && c <= '9')
1210                                   v = (v << 4) + c - '0';
1211                           else if (c >= 'A' && c <= 'F')
1212                                   v = (v << 4) + c - 'A' + 10;
1213                           else if (c >= 'a' && c <= 'f')
1214                                   v = (v << 4) + c - 'a' + 10;
1215                           else
1216                                   synerror("Bad escape sequence");
1217                   }
1218                   if (v == 0 || (v >= 0xd800 && v <= 0xdfff))
1219                           synerror("Bad escape sequence");
1220                   /* We really need iconv here. */
1221                   if (initial_localeisutf8 && v > 127) {
1222                           CHECKSTRSPACE(4, out);
1223                           /*
1224                            * We cannot use wctomb() as the locale may have
1225                            * changed.
1226                            */
1227                           if (v <= 0x7ff) {
1228                                   USTPUTC(0xc0 | v >> 6, out);
1229                                   USTPUTC(0x80 | (v & 0x3f), out);
1230                                   return out;
1231                           } else if (v <= 0xffff) {
1232                                   USTPUTC(0xe0 | v >> 12, out);
1233                                   USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
1234                                   USTPUTC(0x80 | (v & 0x3f), out);
1235                                   return out;
1236                           } else if (v <= 0x10ffff) {
1237                                   USTPUTC(0xf0 | v >> 18, out);
1238                                   USTPUTC(0x80 | ((v >> 12) & 0x3f), out);
1239                                   USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
1240                                   USTPUTC(0x80 | (v & 0x3f), out);
1241                                   return out;
1242                           }
1243                   }
1244                   if (v > 127)
1245                           v = '?';
1246                   break;
1247         default:
1248                   synerror("Bad escape sequence");
1249         }
1250         v = (char)v;
1251         /*
1252          * We can't handle NUL bytes.
1253          * POSIX says we should skip till the closing quote.
1254          */
1255         if (v == '\0') {
1256                 while ((c = pgetc()) != '\'') {
1257                         if (c == '\\')
1258                                 c = pgetc();
1259                         if (c == PEOF)
1260                                 synerror("Unterminated quoted string");
1261                 }
1262                 pungetc();
1263                 return out;
1264         }
1265         if (SQSYNTAX[v] == CCTL)
1266                 USTPUTC(CTLESC, out);
1267         USTPUTC(v, out);
1268         return out;
1269 }
1270
1271
1272 /*
1273  * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
1274  * is not NULL, read a here document.  In the latter case, eofmark is the
1275  * word which marks the end of the document and striptabs is true if
1276  * leading tabs should be stripped from the document.  The argument firstc
1277  * is the first character of the input token or document.
1278  *
1279  * Because C does not have internal subroutines, I have simulated them
1280  * using goto's to implement the subroutine linkage.  The following macros
1281  * will run code that appears at the end of readtoken1.
1282  */
1283
1284 #define CHECKEND()      {goto checkend; checkend_return:;}
1285 #define PARSEREDIR()    {goto parseredir; parseredir_return:;}
1286 #define PARSESUB()      {goto parsesub; parsesub_return:;}
1287 #define PARSEARITH()    {goto parsearith; parsearith_return:;}
1288
1289 static int
1290 readtoken1(int firstc, char const *initialsyntax, char *eofmark, int striptabs)
1291 {
1292         int c = firstc;
1293         char * volatile out;
1294         int len;
1295         char line[EOFMARKLEN + 1];
1296         struct nodelist *bqlist;
1297         volatile int quotef;
1298         int newvarnest;
1299         int level;
1300         int synentry;
1301         struct tokenstate state_static[MAXNEST_STATIC];
1302         int maxnest = MAXNEST_STATIC;
1303         struct tokenstate *state = state_static;
1304         int sqiscstyle = 0;
1305
1306         startlinno = plinno;
1307         quotef = 0;
1308         bqlist = NULL;
1309         newvarnest = 0;
1310         level = 0;
1311         state[level].syntax = initialsyntax;
1312         state[level].parenlevel = 0;
1313         state[level].category = TSTATE_TOP;
1314
1315         STARTSTACKSTR(out);
1316         loop: { /* for each line, until end of word */
1317                 CHECKEND();     /* set c to PEOF if at end of here document */
1318                 for (;;) {      /* until end of line or end of word */
1319                         CHECKSTRSPACE(4, out);  /* permit 4 calls to USTPUTC */
1320
1321                         synentry = state[level].syntax[c];
1322
1323                         switch(synentry) {
1324                         case CNL:       /* '\n' */
1325                                 if (state[level].syntax == BASESYNTAX)
1326                                         goto endword;   /* exit outer loop */
1327                                 USTPUTC(c, out);
1328                                 plinno++;
1329                                 if (doprompt)
1330                                         setprompt(2);
1331                                 else
1332                                         setprompt(0);
1333                                 c = pgetc();
1334                                 goto loop;              /* continue outer loop */
1335                         case CSBACK:
1336                                 if (sqiscstyle) {
1337                                         out = readcstyleesc(out);
1338                                         break;
1339                                 }
1340                                 /* FALLTHROUGH */
1341                         case CWORD:
1342                                 USTPUTC(c, out);
1343                                 break;
1344                         case CCTL:
1345                                 if (eofmark == NULL || initialsyntax != SQSYNTAX)
1346                                         USTPUTC(CTLESC, out);
1347                                 USTPUTC(c, out);
1348                                 break;
1349                         case CBACK:     /* backslash */
1350                                 c = pgetc();
1351                                 if (c == PEOF) {
1352                                         USTPUTC('\\', out);
1353                                         pungetc();
1354                                 } else if (c == '\n') {
1355                                         plinno++;
1356                                         if (doprompt)
1357                                                 setprompt(2);
1358                                         else
1359                                                 setprompt(0);
1360                                 } else {
1361                                         if (state[level].syntax == DQSYNTAX &&
1362                                             c != '\\' && c != '`' && c != '$' &&
1363                                             (c != '"' || (eofmark != NULL &&
1364                                                 newvarnest == 0)) &&
1365                                             (c != '}' || state[level].category != TSTATE_VAR_OLD))
1366                                                 USTPUTC('\\', out);
1367                                         if ((eofmark == NULL ||
1368                                             newvarnest > 0) &&
1369                                             state[level].syntax == BASESYNTAX)
1370                                                 USTPUTC(CTLQUOTEMARK, out);
1371                                         if (SQSYNTAX[c] == CCTL)
1372                                                 USTPUTC(CTLESC, out);
1373                                         USTPUTC(c, out);
1374                                         if ((eofmark == NULL ||
1375                                             newvarnest > 0) &&
1376                                             state[level].syntax == BASESYNTAX &&
1377                                             state[level].category == TSTATE_VAR_OLD)
1378                                                 USTPUTC(CTLQUOTEEND, out);
1379                                         quotef++;
1380                                 }
1381                                 break;
1382                         case CSQUOTE:
1383                                 USTPUTC(CTLQUOTEMARK, out);
1384                                 state[level].syntax = SQSYNTAX;
1385                                 sqiscstyle = 0;
1386                                 break;
1387                         case CDQUOTE:
1388                                 USTPUTC(CTLQUOTEMARK, out);
1389                                 state[level].syntax = DQSYNTAX;
1390                                 break;
1391                         case CENDQUOTE:
1392                                 if (eofmark != NULL && newvarnest == 0)
1393                                         USTPUTC(c, out);
1394                                 else {
1395                                         if (state[level].category == TSTATE_VAR_OLD)
1396                                                 USTPUTC(CTLQUOTEEND, out);
1397                                         state[level].syntax = BASESYNTAX;
1398                                         quotef++;
1399                                 }
1400                                 break;
1401                         case CVAR:      /* '$' */
1402                                 PARSESUB();             /* parse substitution */
1403                                 break;
1404                         case CENDVAR:   /* '}' */
1405                                 if (level > 0 &&
1406                                     ((state[level].category == TSTATE_VAR_OLD &&
1407                                       state[level].syntax ==
1408                                       state[level - 1].syntax) ||
1409                                     (state[level].category == TSTATE_VAR_NEW &&
1410                                      state[level].syntax == BASESYNTAX))) {
1411                                         if (state[level].category == TSTATE_VAR_NEW)
1412                                                 newvarnest--;
1413                                         level--;
1414                                         USTPUTC(CTLENDVAR, out);
1415                                 } else {
1416                                         USTPUTC(c, out);
1417                                 }
1418                                 break;
1419                         case CLP:       /* '(' in arithmetic */
1420                                 state[level].parenlevel++;
1421                                 USTPUTC(c, out);
1422                                 break;
1423                         case CRP:       /* ')' in arithmetic */
1424                                 if (state[level].parenlevel > 0) {
1425                                         USTPUTC(c, out);
1426                                         --state[level].parenlevel;
1427                                 } else {
1428                                         if (pgetc() == ')') {
1429                                                 if (level > 0 &&
1430                                                     state[level].category == TSTATE_ARITH) {
1431                                                         level--;
1432                                                         USTPUTC(CTLENDARI, out);
1433                                                 } else
1434                                                         USTPUTC(')', out);
1435                                         } else {
1436                                                 /*
1437                                                  * unbalanced parens
1438                                                  *  (don't 2nd guess - no error)
1439                                                  */
1440                                                 pungetc();
1441                                                 USTPUTC(')', out);
1442                                         }
1443                                 }
1444                                 break;
1445                         case CBQUOTE:   /* '`' */
1446                                 out = parsebackq(out, &bqlist, 1,
1447                                     state[level].syntax == DQSYNTAX &&
1448                                     (eofmark == NULL || newvarnest > 0),
1449                                     state[level].syntax == DQSYNTAX || state[level].syntax == ARISYNTAX);
1450                                 break;
1451                         case CEOF:
1452                                 goto endword;           /* exit outer loop */
1453                         case CIGN:
1454                                 break;
1455                         default:
1456                                 if (level == 0)
1457                                         goto endword;   /* exit outer loop */
1458                                 USTPUTC(c, out);
1459                         }
1460                         c = pgetc_macro();
1461                 }
1462         }
1463 endword:
1464         if (state[level].syntax == ARISYNTAX)
1465                 synerror("Missing '))'");
1466         if (state[level].syntax != BASESYNTAX && eofmark == NULL)
1467                 synerror("Unterminated quoted string");
1468         if (state[level].category == TSTATE_VAR_OLD ||
1469             state[level].category == TSTATE_VAR_NEW) {
1470                 startlinno = plinno;
1471                 synerror("Missing '}'");
1472         }
1473         if (state != state_static)
1474                 parser_temp_free_upto(state);
1475         USTPUTC('\0', out);
1476         len = out - stackblock();
1477         out = stackblock();
1478         if (eofmark == NULL) {
1479                 if ((c == '>' || c == '<')
1480                  && quotef == 0
1481                  && len <= 2
1482                  && (*out == '\0' || is_digit(*out))) {
1483                         PARSEREDIR();
1484                         return lasttoken = TREDIR;
1485                 } else {
1486                         pungetc();
1487                 }
1488         }
1489         quoteflag = quotef;
1490         backquotelist = bqlist;
1491         grabstackblock(len);
1492         wordtext = out;
1493         return lasttoken = TWORD;
1494 /* end of readtoken routine */
1495
1496
1497 /*
1498  * Check to see whether we are at the end of the here document.  When this
1499  * is called, c is set to the first character of the next input line.  If
1500  * we are at the end of the here document, this routine sets the c to PEOF.
1501  */
1502
1503 checkend: {
1504         if (eofmark) {
1505                 if (striptabs) {
1506                         while (c == '\t')
1507                                 c = pgetc();
1508                 }
1509                 if (c == *eofmark) {
1510                         if (pfgets(line, sizeof line) != NULL) {
1511                                 char *p, *q;
1512
1513                                 p = line;
1514                                 for (q = eofmark + 1 ; *q && *p == *q ; p++, q++);
1515                                 if (*p == '\n' && *q == '\0') {
1516                                         c = PEOF;
1517                                         plinno++;
1518                                         needprompt = doprompt;
1519                                 } else {
1520                                         pushstring(line, strlen(line), NULL);
1521                                 }
1522                         }
1523                 }
1524         }
1525         goto checkend_return;
1526 }
1527
1528
1529 /*
1530  * Parse a redirection operator.  The variable "out" points to a string
1531  * specifying the fd to be redirected.  The variable "c" contains the
1532  * first character of the redirection operator.
1533  */
1534
1535 parseredir: {
1536         char fd = *out;
1537         union node *np;
1538
1539         np = (union node *)stalloc(sizeof (struct nfile));
1540         if (c == '>') {
1541                 np->nfile.fd = 1;
1542                 c = pgetc();
1543                 if (c == '>')
1544                         np->type = NAPPEND;
1545                 else if (c == '&')
1546                         np->type = NTOFD;
1547                 else if (c == '|')
1548                         np->type = NCLOBBER;
1549                 else {
1550                         np->type = NTO;
1551                         pungetc();
1552                 }
1553         } else {        /* c == '<' */
1554                 np->nfile.fd = 0;
1555                 c = pgetc();
1556                 if (c == '<') {
1557                         if (sizeof (struct nfile) != sizeof (struct nhere)) {
1558                                 np = (union node *)stalloc(sizeof (struct nhere));
1559                                 np->nfile.fd = 0;
1560                         }
1561                         np->type = NHERE;
1562                         heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
1563                         heredoc->here = np;
1564                         if ((c = pgetc()) == '-') {
1565                                 heredoc->striptabs = 1;
1566                         } else {
1567                                 heredoc->striptabs = 0;
1568                                 pungetc();
1569                         }
1570                 } else if (c == '&')
1571                         np->type = NFROMFD;
1572                 else if (c == '>')
1573                         np->type = NFROMTO;
1574                 else {
1575                         np->type = NFROM;
1576                         pungetc();
1577                 }
1578         }
1579         if (fd != '\0')
1580                 np->nfile.fd = digit_val(fd);
1581         redirnode = np;
1582         goto parseredir_return;
1583 }
1584
1585
1586 /*
1587  * Parse a substitution.  At this point, we have read the dollar sign
1588  * and nothing else.
1589  */
1590
1591 parsesub: {
1592         char buf[10];
1593         int subtype;
1594         int typeloc;
1595         int flags;
1596         char *p;
1597         static const char types[] = "}-+?=";
1598         int bracketed_name = 0; /* used to handle ${[0-9]*} variables */
1599         int linno;
1600         int length;
1601         int c1;
1602
1603         c = pgetc();
1604         if (c == '(') { /* $(command) or $((arith)) */
1605                 if (pgetc() == '(') {
1606                         PARSEARITH();
1607                 } else {
1608                         pungetc();
1609                         out = parsebackq(out, &bqlist, 0,
1610                             state[level].syntax == DQSYNTAX &&
1611                             (eofmark == NULL || newvarnest > 0),
1612                             state[level].syntax == DQSYNTAX ||
1613                             state[level].syntax == ARISYNTAX);
1614                 }
1615         } else if (c == '{' || is_name(c) || is_special(c)) {
1616                 USTPUTC(CTLVAR, out);
1617                 typeloc = out - stackblock();
1618                 USTPUTC(VSNORMAL, out);
1619                 subtype = VSNORMAL;
1620                 flags = 0;
1621                 if (c == '{') {
1622                         bracketed_name = 1;
1623                         c = pgetc();
1624                         subtype = 0;
1625                 }
1626 varname:
1627                 if (!is_eof(c) && is_name(c)) {
1628                         length = 0;
1629                         do {
1630                                 STPUTC(c, out);
1631                                 c = pgetc();
1632                                 length++;
1633                         } while (!is_eof(c) && is_in_name(c));
1634                         if (length == 6 &&
1635                             strncmp(out - length, "LINENO", length) == 0) {
1636                                 /* Replace the variable name with the
1637                                  * current line number. */
1638                                 linno = plinno;
1639                                 if (funclinno != 0)
1640                                         linno -= funclinno - 1;
1641                                 snprintf(buf, sizeof(buf), "%d", linno);
1642                                 STADJUST(-6, out);
1643                                 STPUTS(buf, out);
1644                                 flags |= VSLINENO;
1645                         }
1646                 } else if (is_digit(c)) {
1647                         if (bracketed_name) {
1648                                 do {
1649                                         STPUTC(c, out);
1650                                         c = pgetc();
1651                                 } while (is_digit(c));
1652                         } else {
1653                                 STPUTC(c, out);
1654                                 c = pgetc();
1655                         }
1656                 } else if (is_special(c)) {
1657                         c1 = c;
1658                         c = pgetc();
1659                         if (subtype == 0 && c1 == '#') {
1660                                 subtype = VSLENGTH;
1661                                 if (strchr(types, c) == NULL && c != ':' &&
1662                                     c != '#' && c != '%')
1663                                         goto varname;
1664                                 c1 = c;
1665                                 c = pgetc();
1666                                 if (c1 != '}' && c == '}') {
1667                                         pungetc();
1668                                         c = c1;
1669                                         goto varname;
1670                                 }
1671                                 pungetc();
1672                                 c = c1;
1673                                 c1 = '#';
1674                                 subtype = 0;
1675                         }
1676                         USTPUTC(c1, out);
1677                 } else {
1678                         subtype = VSERROR;
1679                         if (c == '}')
1680                                 pungetc();
1681                         else if (c == '\n' || c == PEOF)
1682                                 synerror("Unexpected end of line in substitution");
1683                         else
1684                                 USTPUTC(c, out);
1685                 }
1686                 if (subtype == 0) {
1687                         switch (c) {
1688                         case ':':
1689                                 flags |= VSNUL;
1690                                 c = pgetc();
1691                                 /*FALLTHROUGH*/
1692                         default:
1693                                 p = strchr(types, c);
1694                                 if (p == NULL) {
1695                                         if (c == '\n' || c == PEOF)
1696                                                 synerror("Unexpected end of line in substitution");
1697                                         if (flags == VSNUL)
1698                                                 STPUTC(':', out);
1699                                         STPUTC(c, out);
1700                                         subtype = VSERROR;
1701                                 } else
1702                                         subtype = p - types + VSNORMAL;
1703                                 break;
1704                         case '%':
1705                         case '#':
1706                                 {
1707                                         int cc = c;
1708                                         subtype = c == '#' ? VSTRIMLEFT :
1709                                                              VSTRIMRIGHT;
1710                                         c = pgetc();
1711                                         if (c == cc)
1712                                                 subtype++;
1713                                         else
1714                                                 pungetc();
1715                                         break;
1716                                 }
1717                         }
1718                 } else if (subtype != VSERROR) {
1719                         if (subtype == VSLENGTH && c != '}')
1720                                 subtype = VSERROR;
1721                         pungetc();
1722                 }
1723                 STPUTC('=', out);
1724                 if (state[level].syntax == DQSYNTAX ||
1725                     state[level].syntax == ARISYNTAX)
1726                         flags |= VSQUOTE;
1727                 *(stackblock() + typeloc) = subtype | flags;
1728                 if (subtype != VSNORMAL) {
1729                         if (level + 1 >= maxnest) {
1730                                 maxnest *= 2;
1731                                 if (state == state_static) {
1732                                         state = parser_temp_alloc(
1733                                             maxnest * sizeof(*state));
1734                                         memcpy(state, state_static,
1735                                             MAXNEST_STATIC * sizeof(*state));
1736                                 } else
1737                                         state = parser_temp_realloc(state,
1738                                             maxnest * sizeof(*state));
1739                         }
1740                         level++;
1741                         state[level].parenlevel = 0;
1742                         if (subtype == VSMINUS || subtype == VSPLUS ||
1743                             subtype == VSQUESTION || subtype == VSASSIGN) {
1744                                 /*
1745                                  * For operators that were in the Bourne shell,
1746                                  * inherit the double-quote state.
1747                                  */
1748                                 state[level].syntax = state[level - 1].syntax;
1749                                 state[level].category = TSTATE_VAR_OLD;
1750                         } else {
1751                                 /*
1752                                  * The other operators take a pattern,
1753                                  * so go to BASESYNTAX.
1754                                  * Also, ' and " are now special, even
1755                                  * in here documents.
1756                                  */
1757                                 state[level].syntax = BASESYNTAX;
1758                                 state[level].category = TSTATE_VAR_NEW;
1759                                 newvarnest++;
1760                         }
1761                 }
1762         } else if (c == '\'' && state[level].syntax == BASESYNTAX) {
1763                 /* $'cstylequotes' */
1764                 USTPUTC(CTLQUOTEMARK, out);
1765                 state[level].syntax = SQSYNTAX;
1766                 sqiscstyle = 1;
1767         } else {
1768                 USTPUTC('$', out);
1769                 pungetc();
1770         }
1771         goto parsesub_return;
1772 }
1773
1774
1775 /*
1776  * Parse an arithmetic expansion (indicate start of one and set state)
1777  */
1778 parsearith: {
1779
1780         if (level + 1 >= maxnest) {
1781                 maxnest *= 2;
1782                 if (state == state_static) {
1783                         state = parser_temp_alloc(
1784                             maxnest * sizeof(*state));
1785                         memcpy(state, state_static,
1786                             MAXNEST_STATIC * sizeof(*state));
1787                 } else
1788                         state = parser_temp_realloc(state,
1789                             maxnest * sizeof(*state));
1790         }
1791         level++;
1792         state[level].syntax = ARISYNTAX;
1793         state[level].parenlevel = 0;
1794         state[level].category = TSTATE_ARITH;
1795         USTPUTC(CTLARI, out);
1796         if (state[level - 1].syntax == DQSYNTAX)
1797                 USTPUTC('"',out);
1798         else
1799                 USTPUTC(' ',out);
1800         goto parsearith_return;
1801 }
1802
1803 } /* end of readtoken */
1804
1805
1806
1807 #ifdef mkinit
1808 RESET {
1809         tokpushback = 0;
1810         checkkwd = 0;
1811 }
1812 #endif
1813
1814 /*
1815  * Returns true if the text contains nothing to expand (no dollar signs
1816  * or backquotes).
1817  */
1818
1819 static int
1820 noexpand(char *text)
1821 {
1822         char *p;
1823         char c;
1824
1825         p = text;
1826         while ((c = *p++) != '\0') {
1827                 if ( c == CTLQUOTEMARK)
1828                         continue;
1829                 if (c == CTLESC)
1830                         p++;
1831                 else if (BASESYNTAX[(int)c] == CCTL)
1832                         return 0;
1833         }
1834         return 1;
1835 }
1836
1837
1838 /*
1839  * Return true if the argument is a legal variable name (a letter or
1840  * underscore followed by zero or more letters, underscores, and digits).
1841  */
1842
1843 int
1844 goodname(const char *name)
1845 {
1846         const char *p;
1847
1848         p = name;
1849         if (! is_name(*p))
1850                 return 0;
1851         while (*++p) {
1852                 if (! is_in_name(*p))
1853                         return 0;
1854         }
1855         return 1;
1856 }
1857
1858
1859 /*
1860  * Called when an unexpected token is read during the parse.  The argument
1861  * is the token that is expected, or -1 if more than one type of token can
1862  * occur at this point.
1863  */
1864
1865 static void
1866 synexpect(int token)
1867 {
1868         char msg[64];
1869
1870         if (token >= 0) {
1871                 fmtstr(msg, 64, "%s unexpected (expecting %s)",
1872                         tokname[lasttoken], tokname[token]);
1873         } else {
1874                 fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
1875         }
1876         synerror(msg);
1877 }
1878
1879
1880 static void
1881 synerror(const char *msg)
1882 {
1883         if (commandname)
1884                 outfmt(out2, "%s: %d: ", commandname, startlinno);
1885         outfmt(out2, "Syntax error: %s\n", msg);
1886         error(NULL);
1887 }
1888
1889 static void
1890 setprompt(int which)
1891 {
1892         whichprompt = which;
1893
1894 #ifndef NO_HISTORY
1895         if (!el)
1896 #endif
1897         {
1898                 out2str(getprompt(NULL));
1899                 flushout(out2);
1900         }
1901 }
1902
1903 /*
1904  * called by editline -- any expansions to the prompt
1905  *    should be added here.
1906  */
1907 const char *
1908 getprompt(void *unused __unused)
1909 {
1910         static char ps[PROMPTLEN];
1911         const char *fmt;
1912         const char *pwd;
1913         int i, trim;
1914
1915         /*
1916          * Select prompt format.
1917          */
1918         switch (whichprompt) {
1919         case 0:
1920                 fmt = "";
1921                 break;
1922         case 1:
1923                 fmt = ps1val();
1924                 break;
1925         case 2:
1926                 fmt = ps2val();
1927                 break;
1928         default:
1929                 return "??";
1930         }
1931
1932         /*
1933          * Format prompt string.
1934          */
1935         for (i = 0; (i < 127) && (*fmt != '\0'); i++, fmt++)
1936                 if (*fmt == '\\')
1937                         switch (*++fmt) {
1938
1939                                 /*
1940                                  * Hostname.
1941                                  *
1942                                  * \h specifies just the local hostname,
1943                                  * \H specifies fully-qualified hostname.
1944                                  */
1945                         case 'h':
1946                         case 'H':
1947                                 ps[i] = '\0';
1948                                 gethostname(&ps[i], PROMPTLEN - i);
1949                                 /* Skip to end of hostname. */
1950                                 trim = (*fmt == 'h') ? '.' : '\0';
1951                                 while ((ps[i+1] != '\0') && (ps[i+1] != trim))
1952                                         i++;
1953                                 break;
1954
1955                                 /*
1956                                  * Working directory.
1957                                  *
1958                                  * \W specifies just the final component,
1959                                  * \w specifies the entire path.
1960                                  */
1961                         case 'W':
1962                         case 'w':
1963                                 pwd = lookupvar("PWD");
1964                                 if (pwd == NULL)
1965                                         pwd = "?";
1966                                 if (*fmt == 'W' &&
1967                                     *pwd == '/' && pwd[1] != '\0')
1968                                         strlcpy(&ps[i], strrchr(pwd, '/') + 1,
1969                                             PROMPTLEN - i);
1970                                 else
1971                                         strlcpy(&ps[i], pwd, PROMPTLEN - i);
1972                                 /* Skip to end of path. */
1973                                 while (ps[i + 1] != '\0')
1974                                         i++;
1975                                 break;
1976
1977                                 /*
1978                                  * Superuser status.
1979                                  *
1980                                  * '$' for normal users, '#' for root.
1981                                  */
1982                         case '$':
1983                                 ps[i] = (geteuid() != 0) ? '$' : '#';
1984                                 break;
1985
1986                                 /*
1987                                  * A literal \.
1988                                  */
1989                         case '\\':
1990                                 ps[i] = '\\';
1991                                 break;
1992
1993                                 /*
1994                                  * Emit unrecognized formats verbatim.
1995                                  */
1996                         default:
1997                                 ps[i++] = '\\';
1998                                 ps[i] = *fmt;
1999                                 break;
2000                         }
2001                 else
2002                         ps[i] = *fmt;
2003         ps[i] = '\0';
2004         return (ps);
2005 }