bin/sh/parser.c

   1 /*-
   2  * Copyright (c) 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Kenneth Almquist.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 4. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #ifndef lint
  34 #if 0
  35 static char sccsid[] = "@(#)parser.c    8.7 (Berkeley) 5/16/95";
  36 #endif
  37 #endif /* not lint */
  38 #include <sys/cdefs.h>
  39 __FBSDID("$FreeBSD$");
  40
  41 #include <stdlib.h>
  42 #include <unistd.h>
  43 #include <stdio.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 #include "exec.h"       /* to check for special builtins */
  61 #ifndef NO_HISTORY
  62 #include "myhistedit.h"
  63 #endif
  64
  65 /*
  66  * Shell command parser.
  67  */
  68
  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 static int tokpushback;         /* last token pushed back */
  99 static char *wordtext;          /* text of last word returned by readtoken */
 100 static int checkkwd;
 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 #define NOEOFMARK ((const char *)&heredoclist)
 110
 111
 112 static union node *list(int);
 113 static union node *andor(void);
 114 static union node *pipeline(void);
 115 static union node *command(void);
 116 static union node *simplecmd(union node **, union node *);
 117 static union node *makename(void);
 118 static union node *makebinary(int type, union node *n1, union node *n2);
 119 static void parsefname(void);
 120 static void parseheredoc(void);
 121 static int peektoken(void);
 122 static int readtoken(void);
 123 static int xxreadtoken(void);
 124 static int readtoken1(int, const char *, const char *, int);
 125 static int noexpand(char *);
 126 static void consumetoken(int);
 127 static void synexpect(int) __dead2;
 128 static void synerror(const char *) __dead2;
 129 static void setprompt(int);
 130 static int pgetc_linecont(void);
 131
 132
 133 static void *
 134 parser_temp_alloc(size_t len)
 135 {
 136         struct parser_temp *t;
 137
 138         INTOFF;
 139         t = ckmalloc(sizeof(*t));
 140         t->data = NULL;
 141         t->next = parser_temp;
 142         parser_temp = t;
 143         t->data = ckmalloc(len);
 144         INTON;
 145         return t->data;
 146 }
 147
 148
 149 static void *
 150 parser_temp_realloc(void *ptr, size_t len)
 151 {
 152         struct parser_temp *t;
 153
 154         INTOFF;
 155         t = parser_temp;
 156         if (ptr != t->data)
 157                 error("bug: parser_temp_realloc misused");
 158         t->data = ckrealloc(t->data, len);
 159         INTON;
 160         return t->data;
 161 }
 162
 163
 164 static void
 165 parser_temp_free_upto(void *ptr)
 166 {
 167         struct parser_temp *t;
 168         int done = 0;
 169
 170         INTOFF;
 171         while (parser_temp != NULL && !done) {
 172                 t = parser_temp;
 173                 parser_temp = t->next;
 174                 done = t->data == ptr;
 175                 ckfree(t->data);
 176                 ckfree(t);
 177         }
 178         INTON;
 179         if (!done)
 180                 error("bug: parser_temp_free_upto misused");
 181 }
 182
 183
 184 static void
 185 parser_temp_free_all(void)
 186 {
 187         struct parser_temp *t;
 188
 189         INTOFF;
 190         while (parser_temp != NULL) {
 191                 t = parser_temp;
 192                 parser_temp = t->next;
 193                 ckfree(t->data);
 194                 ckfree(t);
 195         }
 196         INTON;
 197 }
 198
 199
 200 /*
 201  * Read and parse a command.  Returns NEOF on end of file.  (NULL is a
 202  * valid parse tree indicating a blank line.)
 203  */
 204
 205 union node *
 206 parsecmd(int interact)
 207 {
 208         int t;
 209
 210         /* This assumes the parser is not re-entered,
 211          * which could happen if we add command substitution on PS1/PS2.
 212          */
 213         parser_temp_free_all();
 214         heredoclist = NULL;
 215
 216         tokpushback = 0;
 217         checkkwd = 0;
 218         doprompt = interact;
 219         if (doprompt)
 220                 setprompt(1);
 221         else
 222                 setprompt(0);
 223         needprompt = 0;
 224         t = readtoken();
 225         if (t == TEOF)
 226                 return NEOF;
 227         if (t == TNL)
 228                 return NULL;
 229         tokpushback++;
 230         return list(1);
 231 }
 232
 233
 234 /*
 235  * Read and parse words for wordexp.
 236  * Returns a list of NARG nodes; NULL if there are no words.
 237  */
 238 union node *
 239 parsewordexp(void)
 240 {
 241         union node *n, *first = NULL, **pnext;
 242         int t;
 243
 244         /* This assumes the parser is not re-entered,
 245          * which could happen if we add command substitution on PS1/PS2.
 246          */
 247         parser_temp_free_all();
 248         heredoclist = NULL;
 249
 250         tokpushback = 0;
 251         checkkwd = 0;
 252         doprompt = 0;
 253         setprompt(0);
 254         needprompt = 0;
 255         pnext = &first;
 256         while ((t = readtoken()) != TEOF) {
 257                 if (t != TWORD)
 258                         synexpect(TWORD);
 259                 n = makename();
 260                 *pnext = n;
 261                 pnext = &n->narg.next;
 262         }
 263         return first;
 264 }
 265
 266
 267 static union node *
 268 list(int nlflag)
 269 {
 270         union node *ntop, *n1, *n2, *n3;
 271         int tok;
 272
 273         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 274         if (!nlflag && tokendlist[peektoken()])
 275                 return NULL;
 276         ntop = n1 = NULL;
 277         for (;;) {
 278                 n2 = andor();
 279                 tok = readtoken();
 280                 if (tok == TBACKGND) {
 281                         if (n2 != NULL && n2->type == NPIPE) {
 282                                 n2->npipe.backgnd = 1;
 283                         } else if (n2 != NULL && n2->type == NREDIR) {
 284                                 n2->type = NBACKGND;
 285                         } else {
 286                                 n3 = (union node *)stalloc(sizeof (struct nredir));
 287                                 n3->type = NBACKGND;
 288                                 n3->nredir.n = n2;
 289                                 n3->nredir.redirect = NULL;
 290                                 n2 = n3;
 291                         }
 292                 }
 293                 if (ntop == NULL)
 294                         ntop = n2;
 295                 else if (n1 == NULL) {
 296                         n1 = makebinary(NSEMI, ntop, n2);
 297                         ntop = n1;
 298                 }
 299                 else {
 300                         n3 = makebinary(NSEMI, n1->nbinary.ch2, n2);
 301                         n1->nbinary.ch2 = n3;
 302                         n1 = n3;
 303                 }
 304                 switch (tok) {
 305                 case TBACKGND:
 306                 case TSEMI:
 307                         tok = readtoken();
 308                         /* FALLTHROUGH */
 309                 case TNL:
 310                         if (tok == TNL) {
 311                                 parseheredoc();
 312                                 if (nlflag)
 313                                         return ntop;
 314                         } else if (tok == TEOF && nlflag) {
 315                                 parseheredoc();
 316                                 return ntop;
 317                         } else {
 318                                 tokpushback++;
 319                         }
 320                         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 321                         if (!nlflag && tokendlist[peektoken()])
 322                                 return ntop;
 323                         break;
 324                 case TEOF:
 325                         if (heredoclist)
 326                                 parseheredoc();
 327                         else
 328                                 pungetc();              /* push back EOF on input */
 329                         return ntop;
 330                 default:
 331                         if (nlflag)
 332                                 synexpect(-1);
 333                         tokpushback++;
 334                         return ntop;
 335                 }
 336         }
 337 }
 338
 339
 340
 341 static union node *
 342 andor(void)
 343 {
 344         union node *n;
 345         int t;
 346
 347         n = pipeline();
 348         for (;;) {
 349                 if ((t = readtoken()) == TAND) {
 350                         t = NAND;
 351                 } else if (t == TOR) {
 352                         t = NOR;
 353                 } else {
 354                         tokpushback++;
 355                         return n;
 356                 }
 357                 n = makebinary(t, n, pipeline());
 358         }
 359 }
 360
 361
 362
 363 static union node *
 364 pipeline(void)
 365 {
 366         union node *n1, *n2, *pipenode;
 367         struct nodelist *lp, *prev;
 368         int negate, t;
 369
 370         negate = 0;
 371         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 372         TRACE(("pipeline: entered\n"));
 373         while (readtoken() == TNOT)
 374                 negate = !negate;
 375         tokpushback++;
 376         n1 = command();
 377         if (readtoken() == TPIPE) {
 378                 pipenode = (union node *)stalloc(sizeof (struct npipe));
 379                 pipenode->type = NPIPE;
 380                 pipenode->npipe.backgnd = 0;
 381                 lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 382                 pipenode->npipe.cmdlist = lp;
 383                 lp->n = n1;
 384                 do {
 385                         prev = lp;
 386                         lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 387                         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 388                         t = readtoken();
 389                         tokpushback++;
 390                         if (t == TNOT)
 391                                 lp->n = pipeline();
 392                         else
 393                                 lp->n = command();
 394                         prev->next = lp;
 395                 } while (readtoken() == TPIPE);
 396                 lp->next = NULL;
 397                 n1 = pipenode;
 398         }
 399         tokpushback++;
 400         if (negate) {
 401                 n2 = (union node *)stalloc(sizeof (struct nnot));
 402                 n2->type = NNOT;
 403                 n2->nnot.com = n1;
 404                 return n2;
 405         } else
 406                 return n1;
 407 }
 408
 409
 410
 411 static union node *
 412 command(void)
 413 {
 414         union node *n1, *n2;
 415         union node *ap, **app;
 416         union node *cp, **cpp;
 417         union node *redir, **rpp;
 418         int t;
 419         int is_subshell;
 420
 421         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 422         is_subshell = 0;
 423         redir = NULL;
 424         n1 = NULL;
 425         rpp = &redir;
 426
 427         /* Check for redirection which may precede command */
 428         while (readtoken() == TREDIR) {
 429                 *rpp = n2 = redirnode;
 430                 rpp = &n2->nfile.next;
 431                 parsefname();
 432         }
 433         tokpushback++;
 434
 435         switch (readtoken()) {
 436         case TIF:
 437                 n1 = (union node *)stalloc(sizeof (struct nif));
 438                 n1->type = NIF;
 439                 if ((n1->nif.test = list(0)) == NULL)
 440                         synexpect(-1);
 441                 consumetoken(TTHEN);
 442                 n1->nif.ifpart = list(0);
 443                 n2 = n1;
 444                 while (readtoken() == TELIF) {
 445                         n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
 446                         n2 = n2->nif.elsepart;
 447                         n2->type = NIF;
 448                         if ((n2->nif.test = list(0)) == NULL)
 449                                 synexpect(-1);
 450                         consumetoken(TTHEN);
 451                         n2->nif.ifpart = list(0);
 452                 }
 453                 if (lasttoken == TELSE)
 454                         n2->nif.elsepart = list(0);
 455                 else {
 456                         n2->nif.elsepart = NULL;
 457                         tokpushback++;
 458                 }
 459                 consumetoken(TFI);
 460                 checkkwd = CHKKWD | CHKALIAS;
 461                 break;
 462         case TWHILE:
 463         case TUNTIL:
 464                 t = lasttoken;
 465                 if ((n1 = list(0)) == NULL)
 466                         synexpect(-1);
 467                 consumetoken(TDO);
 468                 n1 = makebinary((t == TWHILE)? NWHILE : NUNTIL, n1, list(0));
 469                 consumetoken(TDONE);
 470                 checkkwd = CHKKWD | CHKALIAS;
 471                 break;
 472         case TFOR:
 473                 if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
 474                         synerror("Bad for loop variable");
 475                 n1 = (union node *)stalloc(sizeof (struct nfor));
 476                 n1->type = NFOR;
 477                 n1->nfor.var = wordtext;
 478                 while (readtoken() == TNL)
 479                         ;
 480                 if (lasttoken == TWORD && ! quoteflag && equal(wordtext, "in")) {
 481                         app = &ap;
 482                         while (readtoken() == TWORD) {
 483                                 n2 = makename();
 484                                 *app = n2;
 485                                 app = &n2->narg.next;
 486                         }
 487                         *app = NULL;
 488                         n1->nfor.args = ap;
 489                         if (lasttoken != TNL && lasttoken != TSEMI)
 490                                 synexpect(-1);
 491                 } else {
 492                         static char argvars[5] = {
 493                                 CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'
 494                         };
 495                         n2 = (union node *)stalloc(sizeof (struct narg));
 496                         n2->type = NARG;
 497                         n2->narg.text = argvars;
 498                         n2->narg.backquote = NULL;
 499                         n2->narg.next = NULL;
 500                         n1->nfor.args = n2;
 501                         /*
 502                          * Newline or semicolon here is optional (but note
 503                          * that the original Bourne shell only allowed NL).
 504                          */
 505                         if (lasttoken != TNL && lasttoken != TSEMI)
 506                                 tokpushback++;
 507                 }
 508                 checkkwd = CHKNL | CHKKWD | CHKALIAS;
 509                 if ((t = readtoken()) == TDO)
 510                         t = TDONE;
 511                 else if (t == TBEGIN)
 512                         t = TEND;
 513                 else
 514                         synexpect(-1);
 515                 n1->nfor.body = list(0);
 516                 consumetoken(t);
 517                 checkkwd = CHKKWD | CHKALIAS;
 518                 break;
 519         case TCASE:
 520                 n1 = (union node *)stalloc(sizeof (struct ncase));
 521                 n1->type = NCASE;
 522                 consumetoken(TWORD);
 523                 n1->ncase.expr = makename();
 524                 while (readtoken() == TNL);
 525                 if (lasttoken != TWORD || ! equal(wordtext, "in"))
 526                         synerror("expecting \"in\"");
 527                 cpp = &n1->ncase.cases;
 528                 checkkwd = CHKNL | CHKKWD, readtoken();
 529                 while (lasttoken != TESAC) {
 530                         *cpp = cp = (union node *)stalloc(sizeof (struct nclist));
 531                         cp->type = NCLIST;
 532                         app = &cp->nclist.pattern;
 533                         if (lasttoken == TLP)
 534                                 readtoken();
 535                         for (;;) {
 536                                 *app = ap = makename();
 537                                 checkkwd = CHKNL | CHKKWD;
 538                                 if (readtoken() != TPIPE)
 539                                         break;
 540                                 app = &ap->narg.next;
 541                                 readtoken();
 542                         }
 543                         ap->narg.next = NULL;
 544                         if (lasttoken != TRP)
 545                                 synexpect(TRP);
 546                         cp->nclist.body = list(0);
 547
 548                         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 549                         if ((t = readtoken()) != TESAC) {
 550                                 if (t == TENDCASE)
 551                                         ;
 552                                 else if (t == TFALLTHRU)
 553                                         cp->type = NCLISTFALLTHRU;
 554                                 else
 555                                         synexpect(TENDCASE);
 556                                 checkkwd = CHKNL | CHKKWD, readtoken();
 557                         }
 558                         cpp = &cp->nclist.next;
 559                 }
 560                 *cpp = NULL;
 561                 checkkwd = CHKKWD | CHKALIAS;
 562                 break;
 563         case TLP:
 564                 n1 = (union node *)stalloc(sizeof (struct nredir));
 565                 n1->type = NSUBSHELL;
 566                 n1->nredir.n = list(0);
 567                 n1->nredir.redirect = NULL;
 568                 consumetoken(TRP);
 569                 checkkwd = CHKKWD | CHKALIAS;
 570                 is_subshell = 1;
 571                 break;
 572         case TBEGIN:
 573                 n1 = list(0);
 574                 consumetoken(TEND);
 575                 checkkwd = CHKKWD | CHKALIAS;
 576                 break;
 577         /* A simple command must have at least one redirection or word. */
 578         case TBACKGND:
 579         case TSEMI:
 580         case TAND:
 581         case TOR:
 582         case TPIPE:
 583         case TENDCASE:
 584         case TFALLTHRU:
 585         case TEOF:
 586         case TNL:
 587         case TRP:
 588                 if (!redir)
 589                         synexpect(-1);
 590         case TWORD:
 591                 tokpushback++;
 592                 n1 = simplecmd(rpp, redir);
 593                 return n1;
 594         default:
 595                 synexpect(-1);
 596         }
 597
 598         /* Now check for redirection which may follow command */
 599         while (readtoken() == TREDIR) {
 600                 *rpp = n2 = redirnode;
 601                 rpp = &n2->nfile.next;
 602                 parsefname();
 603         }
 604         tokpushback++;
 605         *rpp = NULL;
 606         if (redir) {
 607                 if (!is_subshell) {
 608                         n2 = (union node *)stalloc(sizeof (struct nredir));
 609                         n2->type = NREDIR;
 610                         n2->nredir.n = n1;
 611                         n1 = n2;
 612                 }
 613                 n1->nredir.redirect = redir;
 614         }
 615
 616         return n1;
 617 }
 618
 619
 620 static union node *
 621 simplecmd(union node **rpp, union node *redir)
 622 {
 623         union node *args, **app;
 624         union node **orig_rpp = rpp;
 625         union node *n = NULL;
 626         int special;
 627         int savecheckkwd;
 628
 629         /* If we don't have any redirections already, then we must reset */
 630         /* rpp to be the address of the local redir variable.  */
 631         if (redir == NULL)
 632                 rpp = &redir;
 633
 634         args = NULL;
 635         app = &args;
 636         /*
 637          * We save the incoming value, because we need this for shell
 638          * functions.  There can not be a redirect or an argument between
 639          * the function name and the open parenthesis.
 640          */
 641         orig_rpp = rpp;
 642
 643         savecheckkwd = CHKALIAS;
 644
 645         for (;;) {
 646                 checkkwd = savecheckkwd;
 647                 if (readtoken() == TWORD) {
 648                         n = makename();
 649                         *app = n;
 650                         app = &n->narg.next;
 651                         if (savecheckkwd != 0 && !isassignment(wordtext))
 652                                 savecheckkwd = 0;
 653                 } else if (lasttoken == TREDIR) {
 654                         *rpp = n = redirnode;
 655                         rpp = &n->nfile.next;
 656                         parsefname();   /* read name of redirection file */
 657                 } else if (lasttoken == TLP && app == &args->narg.next
 658                                             && rpp == orig_rpp) {
 659                         /* We have a function */
 660                         consumetoken(TRP);
 661                         funclinno = plinno;
 662                         /*
 663                          * - Require plain text.
 664                          * - Functions with '/' cannot be called.
 665                          * - Reject name=().
 666                          * - Reject ksh extended glob patterns.
 667                          */
 668                         if (!noexpand(n->narg.text) || quoteflag ||
 669                             strchr(n->narg.text, '/') ||
 670                             strchr("!%*+-=?@}~",
 671                                 n->narg.text[strlen(n->narg.text) - 1]))
 672                                 synerror("Bad function name");
 673                         rmescapes(n->narg.text);
 674                         if (find_builtin(n->narg.text, &special) >= 0 &&
 675                             special)
 676                                 synerror("Cannot override a special builtin with a function");
 677                         n->type = NDEFUN;
 678                         n->narg.next = command();
 679                         funclinno = 0;
 680                         return n;
 681                 } else {
 682                         tokpushback++;
 683                         break;
 684                 }
 685         }
 686         *app = NULL;
 687         *rpp = NULL;
 688         n = (union node *)stalloc(sizeof (struct ncmd));
 689         n->type = NCMD;
 690         n->ncmd.args = args;
 691         n->ncmd.redirect = redir;
 692         return n;
 693 }
 694
 695 static union node *
 696 makename(void)
 697 {
 698         union node *n;
 699
 700         n = (union node *)stalloc(sizeof (struct narg));
 701         n->type = NARG;
 702         n->narg.next = NULL;
 703         n->narg.text = wordtext;
 704         n->narg.backquote = backquotelist;
 705         return n;
 706 }
 707
 708 static union node *
 709 makebinary(int type, union node *n1, union node *n2)
 710 {
 711         union node *n;
 712
 713         n = (union node *)stalloc(sizeof (struct nbinary));
 714         n->type = type;
 715         n->nbinary.ch1 = n1;
 716         n->nbinary.ch2 = n2;
 717         return (n);
 718 }
 719
 720 void
 721 forcealias(void)
 722 {
 723         checkkwd |= CHKALIAS;
 724 }
 725
 726 void
 727 fixredir(union node *n, const char *text, int err)
 728 {
 729         TRACE(("Fix redir %s %d\n", text, err));
 730         if (!err)
 731                 n->ndup.vname = NULL;
 732
 733         if (is_digit(text[0]) && text[1] == '\0')
 734                 n->ndup.dupfd = digit_val(text[0]);
 735         else if (text[0] == '-' && text[1] == '\0')
 736                 n->ndup.dupfd = -1;
 737         else {
 738
 739                 if (err)
 740                         synerror("Bad fd number");
 741                 else
 742                         n->ndup.vname = makename();
 743         }
 744 }
 745
 746
 747 static void
 748 parsefname(void)
 749 {
 750         union node *n = redirnode;
 751
 752         consumetoken(TWORD);
 753         if (n->type == NHERE) {
 754                 struct heredoc *here = heredoc;
 755                 struct heredoc *p;
 756
 757                 if (quoteflag == 0)
 758                         n->type = NXHERE;
 759                 TRACE(("Here document %d\n", n->type));
 760                 if (here->striptabs) {
 761                         while (*wordtext == '\t')
 762                                 wordtext++;
 763                 }
 764                 if (! noexpand(wordtext))
 765                         synerror("Illegal eof marker for << redirection");
 766                 rmescapes(wordtext);
 767                 here->eofmark = wordtext;
 768                 here->next = NULL;
 769                 if (heredoclist == NULL)
 770                         heredoclist = here;
 771                 else {
 772                         for (p = heredoclist ; p->next ; p = p->next);
 773                         p->next = here;
 774                 }
 775         } else if (n->type == NTOFD || n->type == NFROMFD) {
 776                 fixredir(n, wordtext, 0);
 777         } else {
 778                 n->nfile.fname = makename();
 779         }
 780 }
 781
 782
 783 /*
 784  * Input any here documents.
 785  */
 786
 787 static void
 788 parseheredoc(void)
 789 {
 790         struct heredoc *here;
 791         union node *n;
 792
 793         while (heredoclist) {
 794                 here = heredoclist;
 795                 heredoclist = here->next;
 796                 if (needprompt) {
 797                         setprompt(2);
 798                         needprompt = 0;
 799                 }
 800                 readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
 801                                 here->eofmark, here->striptabs);
 802                 n = makename();
 803                 here->here->nhere.doc = n;
 804         }
 805 }
 806
 807 static int
 808 peektoken(void)
 809 {
 810         int t;
 811
 812         t = readtoken();
 813         tokpushback++;
 814         return (t);
 815 }
 816
 817 static int
 818 readtoken(void)
 819 {
 820         int t;
 821         struct alias *ap;
 822 #ifdef DEBUG
 823         int alreadyseen = tokpushback;
 824 #endif
 825
 826         top:
 827         t = xxreadtoken();
 828
 829         /*
 830          * eat newlines
 831          */
 832         if (checkkwd & CHKNL) {
 833                 while (t == TNL) {
 834                         parseheredoc();
 835                         t = xxreadtoken();
 836                 }
 837         }
 838
 839         /*
 840          * check for keywords and aliases
 841          */
 842         if (t == TWORD && !quoteflag)
 843         {
 844                 const char * const *pp;
 845
 846                 if (checkkwd & CHKKWD)
 847                         for (pp = parsekwd; *pp; pp++) {
 848                                 if (**pp == *wordtext && equal(*pp, wordtext))
 849                                 {
 850                                         lasttoken = t = pp - parsekwd + KWDOFFSET;
 851                                         TRACE(("keyword %s recognized\n", tokname[t]));
 852                                         goto out;
 853                                 }
 854                         }
 855                 if (checkkwd & CHKALIAS &&
 856                     (ap = lookupalias(wordtext, 1)) != NULL) {
 857                         pushstring(ap->val, strlen(ap->val), ap);
 858                         goto top;
 859                 }
 860         }
 861 out:
 862         if (t != TNOT)
 863                 checkkwd = 0;
 864
 865 #ifdef DEBUG
 866         if (!alreadyseen)
 867             TRACE(("token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 868         else
 869             TRACE(("reread token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 870 #endif
 871         return (t);
 872 }
 873
 874
 875 /*
 876  * Read the next input token.
 877  * If the token is a word, we set backquotelist to the list of cmds in
 878  *      backquotes.  We set quoteflag to true if any part of the word was
 879  *      quoted.
 880  * If the token is TREDIR, then we set redirnode to a structure containing
 881  *      the redirection.
 882  * In all cases, the variable startlinno is set to the number of the line
 883  *      on which the token starts.
 884  *
 885  * [Change comment:  here documents and internal procedures]
 886  * [Readtoken shouldn't have any arguments.  Perhaps we should make the
 887  *  word parsing code into a separate routine.  In this case, readtoken
 888  *  doesn't need to have any internal procedures, but parseword does.
 889  *  We could also make parseoperator in essence the main routine, and
 890  *  have parseword (readtoken1?) handle both words and redirection.]
 891  */
 892
 893 #define RETURN(token)   return lasttoken = token
 894
 895 static int
 896 xxreadtoken(void)
 897 {
 898         int c;
 899
 900         if (tokpushback) {
 901                 tokpushback = 0;
 902                 return lasttoken;
 903         }
 904         if (needprompt) {
 905                 setprompt(2);
 906                 needprompt = 0;
 907         }
 908         startlinno = plinno;
 909         for (;;) {      /* until token or start of word found */
 910                 c = pgetc_macro();
 911                 switch (c) {
 912                 case ' ': case '\t':
 913                         continue;
 914                 case '#':
 915                         while ((c = pgetc()) != '\n' && c != PEOF);
 916                         pungetc();
 917                         continue;
 918                 case '\\':
 919                         if (pgetc() == '\n') {
 920                                 startlinno = ++plinno;
 921                                 if (doprompt)
 922                                         setprompt(2);
 923                                 else
 924                                         setprompt(0);
 925                                 continue;
 926                         }
 927                         pungetc();
 928                         /* FALLTHROUGH */
 929                 default:
 930                         return readtoken1(c, BASESYNTAX, (char *)NULL, 0);
 931                 case '\n':
 932                         plinno++;
 933                         needprompt = doprompt;
 934                         RETURN(TNL);
 935                 case PEOF:
 936                         RETURN(TEOF);
 937                 case '&':
 938                         if (pgetc_linecont() == '&')
 939                                 RETURN(TAND);
 940                         pungetc();
 941                         RETURN(TBACKGND);
 942                 case '|':
 943                         if (pgetc_linecont() == '|')
 944                                 RETURN(TOR);
 945                         pungetc();
 946                         RETURN(TPIPE);
 947                 case ';':
 948                         c = pgetc_linecont();
 949                         if (c == ';')
 950                                 RETURN(TENDCASE);
 951                         else if (c == '&')
 952                                 RETURN(TFALLTHRU);
 953                         pungetc();
 954                         RETURN(TSEMI);
 955                 case '(':
 956                         RETURN(TLP);
 957                 case ')':
 958                         RETURN(TRP);
 959                 }
 960         }
 961 #undef RETURN
 962 }
 963
 964
 965 #define MAXNEST_static 8
 966 struct tokenstate
 967 {
 968         const char *syntax; /* *SYNTAX */
 969         int parenlevel; /* levels of parentheses in arithmetic */
 970         enum tokenstate_category
 971         {
 972                 TSTATE_TOP,
 973                 TSTATE_VAR_OLD, /* ${var+-=?}, inherits dquotes */
 974                 TSTATE_VAR_NEW, /* other ${var...}, own dquote state */
 975                 TSTATE_ARITH
 976         } category;
 977 };
 978
 979
 980 /*
 981  * Check to see whether we are at the end of the here document.  When this
 982  * is called, c is set to the first character of the next input line.  If
 983  * we are at the end of the here document, this routine sets the c to PEOF.
 984  * The new value of c is returned.
 985  */
 986
 987 static int
 988 checkend(int c, const char *eofmark, int striptabs)
 989 {
 990         if (striptabs) {
 991                 while (c == '\t')
 992                         c = pgetc();
 993         }
 994         if (c == *eofmark) {
 995                 int c2;
 996                 const char *q;
 997
 998                 for (q = eofmark + 1; c2 = pgetc(), *q != '\0' && c2 == *q; q++)
 999                         ;
1000                 if ((c2 == PEOF || c2 == '\n') && *q == '\0') {
1001                         c = PEOF;
1002                         if (c2 == '\n') {
1003                                 plinno++;
1004                                 needprompt = doprompt;
1005                         }
1006                 } else {
1007                         pungetc();
1008                         pushstring(eofmark + 1, q - (eofmark + 1), NULL);
1009                 }
1010         } else if (c == '\n' && *eofmark == '\0') {
1011                 c = PEOF;
1012                 plinno++;
1013                 needprompt = doprompt;
1014         }
1015         return (c);
1016 }
1017
1018
1019 /*
1020  * Parse a redirection operator.  The variable "out" points to a string
1021  * specifying the fd to be redirected.  The variable "c" contains the
1022  * first character of the redirection operator.
1023  */
1024
1025 static void
1026 parseredir(char *out, int c)
1027 {
1028         char fd = *out;
1029         union node *np;
1030
1031         np = (union node *)stalloc(sizeof (struct nfile));
1032         if (c == '>') {
1033                 np->nfile.fd = 1;
1034                 c = pgetc_linecont();
1035                 if (c == '>')
1036                         np->type = NAPPEND;
1037                 else if (c == '&')
1038                         np->type = NTOFD;
1039                 else if (c == '|')
1040                         np->type = NCLOBBER;
1041                 else {
1042                         np->type = NTO;
1043                         pungetc();
1044                 }
1045         } else {        /* c == '<' */
1046                 np->nfile.fd = 0;
1047                 c = pgetc_linecont();
1048                 if (c == '<') {
1049                         if (sizeof (struct nfile) != sizeof (struct nhere)) {
1050                                 np = (union node *)stalloc(sizeof (struct nhere));
1051                                 np->nfile.fd = 0;
1052                         }
1053                         np->type = NHERE;
1054                         heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
1055                         heredoc->here = np;
1056                         if ((c = pgetc_linecont()) == '-') {
1057                                 heredoc->striptabs = 1;
1058                         } else {
1059                                 heredoc->striptabs = 0;
1060                                 pungetc();
1061                         }
1062                 } else if (c == '&')
1063                         np->type = NFROMFD;
1064                 else if (c == '>')
1065                         np->type = NFROMTO;
1066                 else {
1067                         np->type = NFROM;
1068                         pungetc();
1069                 }
1070         }
1071         if (fd != '\0')
1072                 np->nfile.fd = digit_val(fd);
1073         redirnode = np;
1074 }
1075
1076 /*
1077  * Called to parse command substitutions.
1078  */
1079
1080 static char *
1081 parsebackq(char *out, struct nodelist **pbqlist,
1082                 int oldstyle, int dblquote, int quoted)
1083 {
1084         struct nodelist **nlpp;
1085         union node *n;
1086         char *volatile str;
1087         struct jmploc jmploc;
1088         struct jmploc *const savehandler = handler;
1089         size_t savelen;
1090         int saveprompt;
1091         const int bq_startlinno = plinno;
1092         char *volatile ostr = NULL;
1093         struct parsefile *const savetopfile = getcurrentfile();
1094         struct heredoc *const saveheredoclist = heredoclist;
1095         struct heredoc *here;
1096
1097         str = NULL;
1098         if (setjmp(jmploc.loc)) {
1099                 popfilesupto(savetopfile);
1100                 if (str)
1101                         ckfree(str);
1102                 if (ostr)
1103                         ckfree(ostr);
1104                 heredoclist = saveheredoclist;
1105                 handler = savehandler;
1106                 if (exception == EXERROR) {
1107                         startlinno = bq_startlinno;
1108                         synerror("Error in command substitution");
1109                 }
1110                 longjmp(handler->loc, 1);
1111         }
1112         INTOFF;
1113         savelen = out - stackblock();
1114         if (savelen > 0) {
1115                 str = ckmalloc(savelen);
1116                 memcpy(str, stackblock(), savelen);
1117         }
1118         handler = &jmploc;
1119         heredoclist = NULL;
1120         INTON;
1121         if (oldstyle) {
1122                 /* We must read until the closing backquote, giving special
1123                    treatment to some slashes, and then push the string and
1124                    reread it as input, interpreting it normally.  */
1125                 char *oout;
1126                 int c;
1127                 int olen;
1128
1129
1130                 STARTSTACKSTR(oout);
1131                 for (;;) {
1132                         if (needprompt) {
1133                                 setprompt(2);
1134                                 needprompt = 0;
1135                         }
1136                         CHECKSTRSPACE(2, oout);
1137                         c = pgetc_linecont();
1138                         if (c == '`')
1139                                 break;
1140                         switch (c) {
1141                         case '\\':
1142                                 c = pgetc();
1143                                 if (c != '\\' && c != '`' && c != '$'
1144                                     && (!dblquote || c != '"'))
1145                                         USTPUTC('\\', oout);
1146                                 break;
1147
1148                         case '\n':
1149                                 plinno++;
1150                                 needprompt = doprompt;
1151                                 break;
1152
1153                         case PEOF:
1154                                 startlinno = plinno;
1155                                 synerror("EOF in backquote substitution");
1156                                 break;
1157
1158                         default:
1159                                 break;
1160                         }
1161                         USTPUTC(c, oout);
1162                 }
1163                 USTPUTC('\0', oout);
1164                 olen = oout - stackblock();
1165                 INTOFF;
1166                 ostr = ckmalloc(olen);
1167                 memcpy(ostr, stackblock(), olen);
1168                 setinputstring(ostr, 1);
1169                 INTON;
1170         }
1171         nlpp = pbqlist;
1172         while (*nlpp)
1173                 nlpp = &(*nlpp)->next;
1174         *nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
1175         (*nlpp)->next = NULL;
1176
1177         if (oldstyle) {
1178                 saveprompt = doprompt;
1179                 doprompt = 0;
1180         }
1181
1182         n = list(0);
1183
1184         if (oldstyle) {
1185                 if (peektoken() != TEOF)
1186                         synexpect(-1);
1187                 doprompt = saveprompt;
1188         } else
1189                 consumetoken(TRP);
1190
1191         (*nlpp)->n = n;
1192         if (oldstyle) {
1193                 /*
1194                  * Start reading from old file again, ignoring any pushed back
1195                  * tokens left from the backquote parsing
1196                  */
1197                 popfile();
1198                 tokpushback = 0;
1199         }
1200         STARTSTACKSTR(out);
1201         CHECKSTRSPACE(savelen + 1, out);
1202         INTOFF;
1203         if (str) {
1204                 memcpy(out, str, savelen);
1205                 STADJUST(savelen, out);
1206                 ckfree(str);
1207                 str = NULL;
1208         }
1209         if (ostr) {
1210                 ckfree(ostr);
1211                 ostr = NULL;
1212         }
1213         here = saveheredoclist;
1214         if (here != NULL) {
1215                 while (here->next != NULL)
1216                         here = here->next;
1217                 here->next = heredoclist;
1218                 heredoclist = saveheredoclist;
1219         }
1220         handler = savehandler;
1221         INTON;
1222         if (quoted)
1223                 USTPUTC(CTLBACKQ | CTLQUOTE, out);
1224         else
1225                 USTPUTC(CTLBACKQ, out);
1226         return out;
1227 }
1228
1229
1230 /*
1231  * Called to parse a backslash escape sequence inside $'...'.
1232  * The backslash has already been read.
1233  */
1234 static char *
1235 readcstyleesc(char *out)
1236 {
1237         int c, vc, i, n;
1238         unsigned int v;
1239
1240         c = pgetc();
1241         switch (c) {
1242         case '\0':
1243                 synerror("Unterminated quoted string");
1244         case '\n':
1245                 plinno++;
1246                 if (doprompt)
1247                         setprompt(2);
1248                 else
1249                         setprompt(0);
1250                 return out;
1251         case '\\':
1252         case '\'':
1253         case '"':
1254                 v = c;
1255                 break;
1256         case 'a': v = '\a'; break;
1257         case 'b': v = '\b'; break;
1258         case 'e': v = '\033'; break;
1259         case 'f': v = '\f'; break;
1260         case 'n': v = '\n'; break;
1261         case 'r': v = '\r'; break;
1262         case 't': v = '\t'; break;
1263         case 'v': v = '\v'; break;
1264         case 'x':
1265                   v = 0;
1266                   for (;;) {
1267                           c = pgetc();
1268                           if (c >= '0' && c <= '9')
1269                                   v = (v << 4) + c - '0';
1270                           else if (c >= 'A' && c <= 'F')
1271                                   v = (v << 4) + c - 'A' + 10;
1272                           else if (c >= 'a' && c <= 'f')
1273                                   v = (v << 4) + c - 'a' + 10;
1274                           else
1275                                   break;
1276                   }
1277                   pungetc();
1278                   break;
1279         case '0': case '1': case '2': case '3':
1280         case '4': case '5': case '6': case '7':
1281                   v = c - '0';
1282                   c = pgetc();
1283                   if (c >= '0' && c <= '7') {
1284                           v <<= 3;
1285                           v += c - '0';
1286                           c = pgetc();
1287                           if (c >= '0' && c <= '7') {
1288                                   v <<= 3;
1289                                   v += c - '0';
1290                           } else
1291                                   pungetc();
1292                   } else
1293                           pungetc();
1294                   break;
1295         case 'c':
1296                   c = pgetc();
1297                   if (c < 0x3f || c > 0x7a || c == 0x60)
1298                           synerror("Bad escape sequence");
1299                   if (c == '\\' && pgetc() != '\\')
1300                           synerror("Bad escape sequence");
1301                   if (c == '?')
1302                           v = 127;
1303                   else
1304                           v = c & 0x1f;
1305                   break;
1306         case 'u':
1307         case 'U':
1308                   n = c == 'U' ? 8 : 4;
1309                   v = 0;
1310                   for (i = 0; i < n; i++) {
1311                           c = pgetc();
1312                           if (c >= '0' && c <= '9')
1313                                   v = (v << 4) + c - '0';
1314                           else if (c >= 'A' && c <= 'F')
1315                                   v = (v << 4) + c - 'A' + 10;
1316                           else if (c >= 'a' && c <= 'f')
1317                                   v = (v << 4) + c - 'a' + 10;
1318                           else
1319                                   synerror("Bad escape sequence");
1320                   }
1321                   if (v == 0 || (v >= 0xd800 && v <= 0xdfff))
1322                           synerror("Bad escape sequence");
1323                   /* We really need iconv here. */
1324                   if (initial_localeisutf8 && v > 127) {
1325                           CHECKSTRSPACE(4, out);
1326                           /*
1327                            * We cannot use wctomb() as the locale may have
1328                            * changed.
1329                            */
1330                           if (v <= 0x7ff) {
1331                                   USTPUTC(0xc0 | v >> 6, out);
1332                                   USTPUTC(0x80 | (v & 0x3f), out);
1333                                   return out;
1334                           } else if (v <= 0xffff) {
1335                                   USTPUTC(0xe0 | v >> 12, out);
1336                                   USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
1337                                   USTPUTC(0x80 | (v & 0x3f), out);
1338                                   return out;
1339                           } else if (v <= 0x10ffff) {
1340                                   USTPUTC(0xf0 | v >> 18, out);
1341                                   USTPUTC(0x80 | ((v >> 12) & 0x3f), out);
1342                                   USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
1343                                   USTPUTC(0x80 | (v & 0x3f), out);
1344                                   return out;
1345                           }
1346                   }
1347                   if (v > 127)
1348                           v = '?';
1349                   break;
1350         default:
1351                   synerror("Bad escape sequence");
1352         }
1353         vc = (char)v;
1354         /*
1355          * We can't handle NUL bytes.
1356          * POSIX says we should skip till the closing quote.
1357          */
1358         if (vc == '\0') {
1359                 while ((c = pgetc()) != '\'') {
1360                         if (c == '\\')
1361                                 c = pgetc();
1362                         if (c == PEOF)
1363                                 synerror("Unterminated quoted string");
1364                         if (c == '\n') {
1365                                 plinno++;
1366                                 if (doprompt)
1367                                         setprompt(2);
1368                                 else
1369                                         setprompt(0);
1370                         }
1371                 }
1372                 pungetc();
1373                 return out;
1374         }
1375         if (SQSYNTAX[vc] == CCTL)
1376                 USTPUTC(CTLESC, out);
1377         USTPUTC(vc, out);
1378         return out;
1379 }
1380
1381
1382 /*
1383  * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
1384  * is not NULL, read a here document.  In the latter case, eofmark is the
1385  * word which marks the end of the document and striptabs is true if
1386  * leading tabs should be stripped from the document.  The argument firstc
1387  * is the first character of the input token or document.
1388  *
1389  * Because C does not have internal subroutines, I have simulated them
1390  * using goto's to implement the subroutine linkage.  The following macros
1391  * will run code that appears at the end of readtoken1.
1392  */
1393
1394 #define PARSESUB()      {goto parsesub; parsesub_return:;}
1395 #define PARSEARITH()    {goto parsearith; parsearith_return:;}
1396
1397 static int
1398 readtoken1(int firstc, char const *initialsyntax, const char *eofmark,
1399     int striptabs)
1400 {
1401         int c = firstc;
1402         char *out;
1403         int len;
1404         struct nodelist *bqlist;
1405         int quotef;
1406         int newvarnest;
1407         int level;
1408         int synentry;
1409         struct tokenstate state_static[MAXNEST_static];
1410         int maxnest = MAXNEST_static;
1411         struct tokenstate *state = state_static;
1412         int sqiscstyle = 0;
1413
1414         startlinno = plinno;
1415         quotef = 0;
1416         bqlist = NULL;
1417         newvarnest = 0;
1418         level = 0;
1419         state[level].syntax = initialsyntax;
1420         state[level].parenlevel = 0;
1421         state[level].category = TSTATE_TOP;
1422
1423         STARTSTACKSTR(out);
1424         loop: { /* for each line, until end of word */
1425                 if (eofmark && eofmark != NOEOFMARK)
1426                         /* set c to PEOF if at end of here document */
1427                         c = checkend(c, eofmark, striptabs);
1428                 for (;;) {      /* until end of line or end of word */
1429                         CHECKSTRSPACE(4, out);  /* permit 4 calls to USTPUTC */
1430
1431                         synentry = state[level].syntax[c];
1432
1433                         switch(synentry) {
1434                         case CNL:       /* '\n' */
1435                                 if (state[level].syntax == BASESYNTAX)
1436                                         goto endword;   /* exit outer loop */
1437                                 USTPUTC(c, out);
1438                                 plinno++;
1439                                 if (doprompt)
1440                                         setprompt(2);
1441                                 else
1442                                         setprompt(0);
1443                                 c = pgetc();
1444                                 goto loop;              /* continue outer loop */
1445                         case CSBACK:
1446                                 if (sqiscstyle) {
1447                                         out = readcstyleesc(out);
1448                                         break;
1449                                 }
1450                                 /* FALLTHROUGH */
1451                         case CWORD:
1452                                 USTPUTC(c, out);
1453                                 break;
1454                         case CCTL:
1455                                 if (eofmark == NULL || initialsyntax != SQSYNTAX)
1456                                         USTPUTC(CTLESC, out);
1457                                 USTPUTC(c, out);
1458                                 break;
1459                         case CBACK:     /* backslash */
1460                                 c = pgetc();
1461                                 if (c == PEOF) {
1462                                         USTPUTC('\\', out);
1463                                         pungetc();
1464                                 } else if (c == '\n') {
1465                                         plinno++;
1466                                         if (doprompt)
1467                                                 setprompt(2);
1468                                         else
1469                                                 setprompt(0);
1470                                 } else {
1471                                         if (state[level].syntax == DQSYNTAX &&
1472                                             c != '\\' && c != '`' && c != '$' &&
1473                                             (c != '"' || (eofmark != NULL &&
1474                                                 newvarnest == 0)) &&
1475                                             (c != '}' || state[level].category != TSTATE_VAR_OLD))
1476                                                 USTPUTC('\\', out);
1477                                         if ((eofmark == NULL ||
1478                                             newvarnest > 0) &&
1479                                             state[level].syntax == BASESYNTAX)
1480                                                 USTPUTC(CTLQUOTEMARK, out);
1481                                         if (SQSYNTAX[c] == CCTL)
1482                                                 USTPUTC(CTLESC, out);
1483                                         USTPUTC(c, out);
1484                                         if ((eofmark == NULL ||
1485                                             newvarnest > 0) &&
1486                                             state[level].syntax == BASESYNTAX &&
1487                                             state[level].category == TSTATE_VAR_OLD)
1488                                                 USTPUTC(CTLQUOTEEND, out);
1489                                         quotef++;
1490                                 }
1491                                 break;
1492                         case CSQUOTE:
1493                                 USTPUTC(CTLQUOTEMARK, out);
1494                                 state[level].syntax = SQSYNTAX;
1495                                 sqiscstyle = 0;
1496                                 break;
1497                         case CDQUOTE:
1498                                 USTPUTC(CTLQUOTEMARK, out);
1499                                 state[level].syntax = DQSYNTAX;
1500                                 break;
1501                         case CENDQUOTE:
1502                                 if (eofmark != NULL && newvarnest == 0)
1503                                         USTPUTC(c, out);
1504                                 else {
1505                                         if (state[level].category == TSTATE_VAR_OLD)
1506                                                 USTPUTC(CTLQUOTEEND, out);
1507                                         state[level].syntax = BASESYNTAX;
1508                                         quotef++;
1509                                 }
1510                                 break;
1511                         case CVAR:      /* '$' */
1512                                 PARSESUB();             /* parse substitution */
1513                                 break;
1514                         case CENDVAR:   /* '}' */
1515                                 if (level > 0 &&
1516                                     ((state[level].category == TSTATE_VAR_OLD &&
1517                                       state[level].syntax ==
1518                                       state[level - 1].syntax) ||
1519                                     (state[level].category == TSTATE_VAR_NEW &&
1520                                      state[level].syntax == BASESYNTAX))) {
1521                                         if (state[level].category == TSTATE_VAR_NEW)
1522                                                 newvarnest--;
1523                                         level--;
1524                                         USTPUTC(CTLENDVAR, out);
1525                                 } else {
1526                                         USTPUTC(c, out);
1527                                 }
1528                                 break;
1529                         case CLP:       /* '(' in arithmetic */
1530                                 state[level].parenlevel++;
1531                                 USTPUTC(c, out);
1532                                 break;
1533                         case CRP:       /* ')' in arithmetic */
1534                                 if (state[level].parenlevel > 0) {
1535                                         USTPUTC(c, out);
1536                                         --state[level].parenlevel;
1537                                 } else {
1538                                         if (pgetc_linecont() == ')') {
1539                                                 if (level > 0 &&
1540                                                     state[level].category == TSTATE_ARITH) {
1541                                                         level--;
1542                                                         USTPUTC(CTLENDARI, out);
1543                                                 } else
1544                                                         USTPUTC(')', out);
1545                                         } else {
1546                                                 /*
1547                                                  * unbalanced parens
1548                                                  *  (don't 2nd guess - no error)
1549                                                  */
1550                                                 pungetc();
1551                                                 USTPUTC(')', out);
1552                                         }
1553                                 }
1554                                 break;
1555                         case CBQUOTE:   /* '`' */
1556                                 out = parsebackq(out, &bqlist, 1,
1557                                     state[level].syntax == DQSYNTAX &&
1558                                     (eofmark == NULL || newvarnest > 0),
1559                                     state[level].syntax == DQSYNTAX || state[level].syntax == ARISYNTAX);
1560                                 break;
1561                         case CEOF:
1562                                 goto endword;           /* exit outer loop */
1563                         case CIGN:
1564                                 break;
1565                         default:
1566                                 if (level == 0)
1567                                         goto endword;   /* exit outer loop */
1568                                 USTPUTC(c, out);
1569                         }
1570                         c = pgetc_macro();
1571                 }
1572         }
1573 endword:
1574         if (state[level].syntax == ARISYNTAX)
1575                 synerror("Missing '))'");
1576         if (state[level].syntax != BASESYNTAX && eofmark == NULL)
1577                 synerror("Unterminated quoted string");
1578         if (state[level].category == TSTATE_VAR_OLD ||
1579             state[level].category == TSTATE_VAR_NEW) {
1580                 startlinno = plinno;
1581                 synerror("Missing '}'");
1582         }
1583         if (state != state_static)
1584                 parser_temp_free_upto(state);
1585         USTPUTC('\0', out);
1586         len = out - stackblock();
1587         out = stackblock();
1588         if (eofmark == NULL) {
1589                 if ((c == '>' || c == '<')
1590                  && quotef == 0
1591                  && len <= 2
1592                  && (*out == '\0' || is_digit(*out))) {
1593                         parseredir(out, c);
1594                         return lasttoken = TREDIR;
1595                 } else {
1596                         pungetc();
1597                 }
1598         }
1599         quoteflag = quotef;
1600         backquotelist = bqlist;
1601         grabstackblock(len);
1602         wordtext = out;
1603         return lasttoken = TWORD;
1604 /* end of readtoken routine */
1605
1606
1607 /*
1608  * Parse a substitution.  At this point, we have read the dollar sign
1609  * and nothing else.
1610  */
1611
1612 parsesub: {
1613         int subtype;
1614         int typeloc;
1615         int flags;
1616         char *p;
1617         static const char types[] = "}-+?=";
1618         int linno;
1619         int length;
1620         int c1;
1621
1622         c = pgetc_linecont();
1623         if (c == '(') { /* $(command) or $((arith)) */
1624                 if (pgetc_linecont() == '(') {
1625                         PARSEARITH();
1626                 } else {
1627                         pungetc();
1628                         out = parsebackq(out, &bqlist, 0,
1629                             state[level].syntax == DQSYNTAX &&
1630                             (eofmark == NULL || newvarnest > 0),
1631                             state[level].syntax == DQSYNTAX ||
1632                             state[level].syntax == ARISYNTAX);
1633                 }
1634         } else if (c == '{' || is_name(c) || is_special(c)) {
1635                 USTPUTC(CTLVAR, out);
1636                 typeloc = out - stackblock();
1637                 USTPUTC(VSNORMAL, out);
1638                 subtype = VSNORMAL;
1639                 flags = 0;
1640                 if (c == '{') {
1641                         c = pgetc_linecont();
1642                         subtype = 0;
1643                 }
1644 varname:
1645                 if (!is_eof(c) && is_name(c)) {
1646                         length = 0;
1647                         do {
1648                                 STPUTC(c, out);
1649                                 c = pgetc_linecont();
1650                                 length++;
1651                         } while (!is_eof(c) && is_in_name(c));
1652                         if (length == 6 &&
1653                             strncmp(out - length, "LINENO", length) == 0) {
1654                                 /* Replace the variable name with the
1655                                  * current line number. */
1656                                 STADJUST(-6, out);
1657                                 CHECKSTRSPACE(11, out);
1658                                 linno = plinno;
1659                                 if (funclinno != 0)
1660                                         linno -= funclinno - 1;
1661                                 length = snprintf(out, 11, "%d", linno);
1662                                 if (length > 10)
1663                                         length = 10;
1664                                 out += length;
1665                                 flags |= VSLINENO;
1666                         }
1667                 } else if (is_digit(c)) {
1668                         if (subtype != VSNORMAL) {
1669                                 do {
1670                                         STPUTC(c, out);
1671                                         c = pgetc_linecont();
1672                                 } while (is_digit(c));
1673                         } else {
1674                                 USTPUTC(c, out);
1675                                 c = pgetc_linecont();
1676                         }
1677                 } else if (is_special(c)) {
1678                         c1 = c;
1679                         c = pgetc_linecont();
1680                         if (subtype == 0 && c1 == '#') {
1681                                 subtype = VSLENGTH;
1682                                 if (strchr(types, c) == NULL && c != ':' &&
1683                                     c != '#' && c != '%')
1684                                         goto varname;
1685                                 c1 = c;
1686                                 c = pgetc_linecont();
1687                                 if (c1 != '}' && c == '}') {
1688                                         pungetc();
1689                                         c = c1;
1690                                         goto varname;
1691                                 }
1692                                 pungetc();
1693                                 c = c1;
1694                                 c1 = '#';
1695                                 subtype = 0;
1696                         }
1697                         USTPUTC(c1, out);
1698                 } else {
1699                         subtype = VSERROR;
1700                         if (c == '}')
1701                                 pungetc();
1702                         else if (c == '\n' || c == PEOF)
1703                                 synerror("Unexpected end of line in substitution");
1704                         else if (BASESYNTAX[c] != CCTL)
1705                                 USTPUTC(c, out);
1706                 }
1707                 if (subtype == 0) {
1708                         switch (c) {
1709                         case ':':
1710                                 flags |= VSNUL;
1711                                 c = pgetc_linecont();
1712                                 /*FALLTHROUGH*/
1713                         default:
1714                                 p = strchr(types, c);
1715                                 if (p == NULL) {
1716                                         if (c == '\n' || c == PEOF)
1717                                                 synerror("Unexpected end of line in substitution");
1718                                         if (flags == VSNUL)
1719                                                 STPUTC(':', out);
1720                                         if (BASESYNTAX[c] != CCTL)
1721                                                 STPUTC(c, out);
1722                                         subtype = VSERROR;
1723                                 } else
1724                                         subtype = p - types + VSNORMAL;
1725                                 break;
1726                         case '%':
1727                         case '#':
1728                                 {
1729                                         int cc = c;
1730                                         subtype = c == '#' ? VSTRIMLEFT :
1731                                                              VSTRIMRIGHT;
1732                                         c = pgetc_linecont();
1733                                         if (c == cc)
1734                                                 subtype++;
1735                                         else
1736                                                 pungetc();
1737                                         break;
1738                                 }
1739                         }
1740                 } else if (subtype != VSERROR) {
1741                         if (subtype == VSLENGTH && c != '}')
1742                                 subtype = VSERROR;
1743                         pungetc();
1744                 }
1745                 STPUTC('=', out);
1746                 if (state[level].syntax == DQSYNTAX ||
1747                     state[level].syntax == ARISYNTAX)
1748                         flags |= VSQUOTE;
1749                 *(stackblock() + typeloc) = subtype | flags;
1750                 if (subtype != VSNORMAL) {
1751                         if (level + 1 >= maxnest) {
1752                                 maxnest *= 2;
1753                                 if (state == state_static) {
1754                                         state = parser_temp_alloc(
1755                                             maxnest * sizeof(*state));
1756                                         memcpy(state, state_static,
1757                                             MAXNEST_static * sizeof(*state));
1758                                 } else
1759                                         state = parser_temp_realloc(state,
1760                                             maxnest * sizeof(*state));
1761                         }
1762                         level++;
1763                         state[level].parenlevel = 0;
1764                         if (subtype == VSMINUS || subtype == VSPLUS ||
1765                             subtype == VSQUESTION || subtype == VSASSIGN) {
1766                                 /*
1767                                  * For operators that were in the Bourne shell,
1768                                  * inherit the double-quote state.
1769                                  */
1770                                 state[level].syntax = state[level - 1].syntax;
1771                                 state[level].category = TSTATE_VAR_OLD;
1772                         } else {
1773                                 /*
1774                                  * The other operators take a pattern,
1775                                  * so go to BASESYNTAX.
1776                                  * Also, ' and " are now special, even
1777                                  * in here documents.
1778                                  */
1779                                 state[level].syntax = BASESYNTAX;
1780                                 state[level].category = TSTATE_VAR_NEW;
1781                                 newvarnest++;
1782                         }
1783                 }
1784         } else if (c == '\'' && state[level].syntax == BASESYNTAX) {
1785                 /* $'cstylequotes' */
1786                 USTPUTC(CTLQUOTEMARK, out);
1787                 state[level].syntax = SQSYNTAX;
1788                 sqiscstyle = 1;
1789         } else {
1790                 USTPUTC('$', out);
1791                 pungetc();
1792         }
1793         goto parsesub_return;
1794 }
1795
1796
1797 /*
1798  * Parse an arithmetic expansion (indicate start of one and set state)
1799  */
1800 parsearith: {
1801
1802         if (level + 1 >= maxnest) {
1803                 maxnest *= 2;
1804                 if (state == state_static) {
1805                         state = parser_temp_alloc(
1806                             maxnest * sizeof(*state));
1807                         memcpy(state, state_static,
1808                             MAXNEST_static * sizeof(*state));
1809                 } else
1810                         state = parser_temp_realloc(state,
1811                             maxnest * sizeof(*state));
1812         }
1813         level++;
1814         state[level].syntax = ARISYNTAX;
1815         state[level].parenlevel = 0;
1816         state[level].category = TSTATE_ARITH;
1817         USTPUTC(CTLARI, out);
1818         if (state[level - 1].syntax == DQSYNTAX)
1819                 USTPUTC('"',out);
1820         else
1821                 USTPUTC(' ',out);
1822         goto parsearith_return;
1823 }
1824
1825 } /* end of readtoken */
1826
1827
1828 /*
1829  * Returns true if the text contains nothing to expand (no dollar signs
1830  * or backquotes).
1831  */
1832
1833 static int
1834 noexpand(char *text)
1835 {
1836         char *p;
1837         char c;
1838
1839         p = text;
1840         while ((c = *p++) != '\0') {
1841                 if ( c == CTLQUOTEMARK)
1842                         continue;
1843                 if (c == CTLESC)
1844                         p++;
1845                 else if (BASESYNTAX[(int)c] == CCTL)
1846                         return 0;
1847         }
1848         return 1;
1849 }
1850
1851
1852 /*
1853  * Return true if the argument is a legal variable name (a letter or
1854  * underscore followed by zero or more letters, underscores, and digits).
1855  */
1856
1857 int
1858 goodname(const char *name)
1859 {
1860         const char *p;
1861
1862         p = name;
1863         if (! is_name(*p))
1864                 return 0;
1865         while (*++p) {
1866                 if (! is_in_name(*p))
1867                         return 0;
1868         }
1869         return 1;
1870 }
1871
1872
1873 int
1874 isassignment(const char *p)
1875 {
1876         if (!is_name(*p))
1877                 return 0;
1878         p++;
1879         for (;;) {
1880                 if (*p == '=')
1881                         return 1;
1882                 else if (!is_in_name(*p))
1883                         return 0;
1884                 p++;
1885         }
1886 }
1887
1888
1889 static void
1890 consumetoken(int token)
1891 {
1892         if (readtoken() != token)
1893                 synexpect(token);
1894 }
1895
1896
1897 /*
1898  * Called when an unexpected token is read during the parse.  The argument
1899  * is the token that is expected, or -1 if more than one type of token can
1900  * occur at this point.
1901  */
1902
1903 static void
1904 synexpect(int token)
1905 {
1906         char msg[64];
1907
1908         if (token >= 0) {
1909                 fmtstr(msg, 64, "%s unexpected (expecting %s)",
1910                         tokname[lasttoken], tokname[token]);
1911         } else {
1912                 fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
1913         }
1914         synerror(msg);
1915 }
1916
1917
1918 static void
1919 synerror(const char *msg)
1920 {
1921         if (commandname)
1922                 outfmt(out2, "%s: %d: ", commandname, startlinno);
1923         else if (arg0)
1924                 outfmt(out2, "%s: ", arg0);
1925         outfmt(out2, "Syntax error: %s\n", msg);
1926         error((char *)NULL);
1927 }
1928
1929 static void
1930 setprompt(int which)
1931 {
1932         whichprompt = which;
1933         if (which == 0)
1934                 return;
1935
1936 #ifndef NO_HISTORY
1937         if (!el)
1938 #endif
1939         {
1940                 out2str(getprompt(NULL));
1941                 flushout(out2);
1942         }
1943 }
1944
1945 static int
1946 pgetc_linecont(void)
1947 {
1948         int c;
1949
1950         while ((c = pgetc_macro()) == '\\') {
1951                 c = pgetc();
1952                 if (c == '\n') {
1953                         plinno++;
1954                         if (doprompt)
1955                                 setprompt(2);
1956                         else
1957                                 setprompt(0);
1958                 } else {
1959                         pungetc();
1960                         /* Allow the backslash to be pushed back. */
1961                         pushstring("\\", 1, NULL);
1962                         return (pgetc());
1963                 }
1964         }
1965         return (c);
1966 }
1967
1968 /*
1969  * called by editline -- any expansions to the prompt
1970  *    should be added here.
1971  */
1972 char *
1973 getprompt(void *unused __unused)
1974 {
1975         static char ps[PROMPTLEN];
1976         const char *fmt;
1977         const char *pwd;
1978         int i, trim;
1979         static char internal_error[] = "??";
1980
1981         /*
1982          * Select prompt format.
1983          */
1984         switch (whichprompt) {
1985         case 0:
1986                 fmt = "";
1987                 break;
1988         case 1:
1989                 fmt = ps1val();
1990                 break;
1991         case 2:
1992                 fmt = ps2val();
1993                 break;
1994         default:
1995                 return internal_error;
1996         }
1997
1998         /*
1999          * Format prompt string.
2000          */
2001         for (i = 0; (i < PROMPTLEN - 1) && (*fmt != '\0'); i++, fmt++)
2002                 if (*fmt == '\\')
2003                         switch (*++fmt) {
2004
2005                                 /*
2006                                  * Hostname.
2007                                  *
2008                                  * \h specifies just the local hostname,
2009                                  * \H specifies fully-qualified hostname.
2010                                  */
2011                         case 'h':
2012                         case 'H':
2013                                 ps[i] = '\0';
2014                                 gethostname(&ps[i], PROMPTLEN - i - 1);
2015                                 ps[PROMPTLEN - 1] = '\0';
2016                                 /* Skip to end of hostname. */
2017                                 trim = (*fmt == 'h') ? '.' : '\0';
2018                                 while ((ps[i] != '\0') && (ps[i] != trim))
2019                                         i++;
2020                                 --i;
2021                                 break;
2022
2023                                 /*
2024                                  * Working directory.
2025                                  *
2026                                  * \W specifies just the final component,
2027                                  * \w specifies the entire path.
2028                                  */
2029                         case 'W':
2030                         case 'w':
2031                                 pwd = lookupvar("PWD");
2032                                 if (pwd == NULL || *pwd == '\0')
2033                                         pwd = "?";
2034                                 if (*fmt == 'W' &&
2035                                     *pwd == '/' && pwd[1] != '\0')
2036                                         strlcpy(&ps[i], strrchr(pwd, '/') + 1,
2037                                             PROMPTLEN - i);
2038                                 else
2039                                         strlcpy(&ps[i], pwd, PROMPTLEN - i);
2040                                 /* Skip to end of path. */
2041                                 while (ps[i + 1] != '\0')
2042                                         i++;
2043                                 break;
2044
2045                                 /*
2046                                  * Superuser status.
2047                                  *
2048                                  * '$' for normal users, '#' for root.
2049                                  */
2050                         case '$':
2051                                 ps[i] = (geteuid() != 0) ? '$' : '#';
2052                                 break;
2053
2054                                 /*
2055                                  * A literal \.
2056                                  */
2057                         case '\\':
2058                                 ps[i] = '\\';
2059                                 break;
2060
2061                                 /*
2062                                  * Emit unrecognized formats verbatim.
2063                                  */
2064                         default:
2065                                 ps[i] = '\\';
2066                                 if (i < PROMPTLEN - 2)
2067                                         ps[++i] = *fmt;
2068                                 break;
2069                         }
2070                 else
2071                         ps[i] = *fmt;
2072         ps[i] = '\0';
2073         return (ps);
2074 }
2075
2076
2077 const char *
2078 expandstr(const char *ps)
2079 {
2080         union node n;
2081         struct jmploc jmploc;
2082         struct jmploc *const savehandler = handler;
2083         const int saveprompt = doprompt;
2084         struct parsefile *const savetopfile = getcurrentfile();
2085         struct parser_temp *const saveparser_temp = parser_temp;
2086         const char *result = NULL;
2087
2088         if (!setjmp(jmploc.loc)) {
2089                 handler = &jmploc;
2090                 parser_temp = NULL;
2091                 setinputstring(ps, 1);
2092                 doprompt = 0;
2093                 readtoken1(pgetc(), DQSYNTAX, NOEOFMARK, 0);
2094                 if (backquotelist != NULL)
2095                         error("Command substitution not allowed here");
2096
2097                 n.narg.type = NARG;
2098                 n.narg.next = NULL;
2099                 n.narg.text = wordtext;
2100                 n.narg.backquote = backquotelist;
2101
2102                 expandarg(&n, NULL, 0);
2103                 result = stackblock();
2104                 INTOFF;
2105         }
2106         handler = savehandler;
2107         doprompt = saveprompt;
2108         popfilesupto(savetopfile);
2109         if (parser_temp != saveparser_temp) {
2110                 parser_temp_free_all();
2111                 parser_temp = saveparser_temp;
2112         }
2113         if (result != NULL) {
2114                 INTON;
2115         } else if (exception == EXINT)
2116                 raise(SIGINT);
2117         return result;
2118 }