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 1.115 2011/06/18 23:58:59 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 == NPIPE) {
 243                                 n2->npipe.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                                         ;
 546                                 else if (t == TFALLTHRU)
 547                                         cp->type = NCLISTFALLTHRU;
 548                                 else
 549                                         synexpect(TENDCASE);
 550                                 checkkwd = CHKNL | CHKKWD, readtoken();
 551                         }
 552                         cpp = &cp->nclist.next;
 553                 }
 554                 *cpp = NULL;
 555                 checkkwd = CHKKWD | CHKALIAS;
 556                 break;
 557         case TLP:
 558                 n1 = (union node *)stalloc(sizeof (struct nredir));
 559                 n1->type = NSUBSHELL;
 560                 n1->nredir.n = list(0, 0);
 561                 n1->nredir.redirect = NULL;
 562                 if (readtoken() != TRP)
 563                         synexpect(TRP);
 564                 checkkwd = CHKKWD | CHKALIAS;
 565                 is_subshell = 1;
 566                 break;
 567         case TBEGIN:
 568                 n1 = list(0, 0);
 569                 if (readtoken() != TEND)
 570                         synexpect(TEND);
 571                 checkkwd = CHKKWD | CHKALIAS;
 572                 break;
 573         /* Handle an empty command like other simple commands.  */
 574         case TBACKGND:
 575         case TSEMI:
 576         case TAND:
 577         case TOR:
 578                 /*
 579                  * An empty command before a ; doesn't make much sense, and
 580                  * should certainly be disallowed in the case of `if ;'.
 581                  */
 582                 if (!redir)
 583                         synexpect(-1);
 584         case TNL:
 585         case TEOF:
 586         case TWORD:
 587         case TRP:
 588                 tokpushback++;
 589                 n1 = simplecmd(rpp, redir);
 590                 return n1;
 591         default:
 592                 synexpect(-1);
 593         }
 594
 595         /* Now check for redirection which may follow command */
 596         while (readtoken() == TREDIR) {
 597                 *rpp = n2 = redirnode;
 598                 rpp = &n2->nfile.next;
 599                 parsefname();
 600         }
 601         tokpushback++;
 602         *rpp = NULL;
 603         if (redir) {
 604                 if (!is_subshell) {
 605                         n2 = (union node *)stalloc(sizeof (struct nredir));
 606                         n2->type = NREDIR;
 607                         n2->nredir.n = n1;
 608                         n1 = n2;
 609                 }
 610                 n1->nredir.redirect = redir;
 611         }
 612
 613         return n1;
 614 }
 615
 616
 617 static union node *
 618 simplecmd(union node **rpp, union node *redir)
 619 {
 620         union node *args, **app;
 621         union node **orig_rpp = rpp;
 622         union node *n = NULL;
 623         int special;
 624         int savecheckkwd;
 625
 626         /* If we don't have any redirections already, then we must reset */
 627         /* rpp to be the address of the local redir variable.  */
 628         if (redir == NULL)
 629                 rpp = &redir;
 630
 631         args = NULL;
 632         app = &args;
 633         /*
 634          * We save the incoming value, because we need this for shell
 635          * functions.  There can not be a redirect or an argument between
 636          * the function name and the open parenthesis.
 637          */
 638         orig_rpp = rpp;
 639
 640         savecheckkwd = CHKALIAS;
 641
 642         for (;;) {
 643                 checkkwd = savecheckkwd;
 644                 if (readtoken() == TWORD) {
 645                         n = (union node *)stalloc(sizeof (struct narg));
 646                         n->type = NARG;
 647                         n->narg.text = wordtext;
 648                         n->narg.backquote = backquotelist;
 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                         if (readtoken() != TRP)
 661                                 synexpect(TRP);
 662                         funclinno = plinno;
 663                         /*
 664                          * - Require plain text.
 665                          * - Functions with '/' cannot be called.
 666                          * - Reject name=().
 667                          * - Reject ksh extended glob patterns.
 668                          */
 669                         if (!noexpand(n->narg.text) || quoteflag ||
 670                             strchr(n->narg.text, '/') ||
 671                             strchr("!%*+-=?@}~",
 672                                 n->narg.text[strlen(n->narg.text) - 1]))
 673                                 synerror("Bad function name");
 674                         rmescapes(n->narg.text);
 675                         if (find_builtin(n->narg.text, &special) >= 0 &&
 676                             special)
 677                                 synerror("Cannot override a special builtin with a function");
 678                         n->type = NDEFUN;
 679                         n->narg.next = command();
 680                         funclinno = 0;
 681                         return n;
 682                 } else {
 683                         tokpushback++;
 684                         break;
 685                 }
 686         }
 687         *app = NULL;
 688         *rpp = NULL;
 689         n = (union node *)stalloc(sizeof (struct ncmd));
 690         n->type = NCMD;
 691         n->ncmd.args = args;
 692         n->ncmd.redirect = redir;
 693         return n;
 694 }
 695
 696 static union node *
 697 makename(void)
 698 {
 699         union node *n;
 700
 701         n = (union node *)stalloc(sizeof (struct narg));
 702         n->type = NARG;
 703         n->narg.next = NULL;
 704         n->narg.text = wordtext;
 705         n->narg.backquote = backquotelist;
 706         return n;
 707 }
 708
 709 void
 710 fixredir(union node *n, const char *text, int err)
 711 {
 712         TRACE(("Fix redir %s %d\n", text, err));
 713         if (!err)
 714                 n->ndup.vname = NULL;
 715
 716         if (is_digit(text[0]) && text[1] == '\0')
 717                 n->ndup.dupfd = digit_val(text[0]);
 718         else if (text[0] == '-' && text[1] == '\0')
 719                 n->ndup.dupfd = -1;
 720         else {
 721
 722                 if (err)
 723                         synerror("Bad fd number");
 724                 else
 725                         n->ndup.vname = makename();
 726         }
 727 }
 728
 729
 730 static void
 731 parsefname(void)
 732 {
 733         union node *n = redirnode;
 734
 735         if (readtoken() != TWORD)
 736                 synexpect(-1);
 737         if (n->type == NHERE) {
 738                 struct heredoc *here = heredoc;
 739                 struct heredoc *p;
 740                 int i;
 741
 742                 if (quoteflag == 0)
 743                         n->type = NXHERE;
 744                 TRACE(("Here document %d\n", n->type));
 745                 if (here->striptabs) {
 746                         while (*wordtext == '\t')
 747                                 wordtext++;
 748                 }
 749                 if (! noexpand(wordtext) || (i = strlen(wordtext)) == 0 || i > EOFMARKLEN)
 750                         synerror("Illegal eof marker for << redirection");
 751                 rmescapes(wordtext);
 752                 here->eofmark = wordtext;
 753                 here->next = NULL;
 754                 if (heredoclist == NULL)
 755                         heredoclist = here;
 756                 else {
 757                         for (p = heredoclist ; p->next ; p = p->next);
 758                         p->next = here;
 759                 }
 760         } else if (n->type == NTOFD || n->type == NFROMFD) {
 761                 fixredir(n, wordtext, 0);
 762         } else {
 763                 n->nfile.fname = makename();
 764         }
 765 }
 766
 767
 768 /*
 769  * Input any here documents.
 770  */
 771
 772 static void
 773 parseheredoc(void)
 774 {
 775         struct heredoc *here;
 776         union node *n;
 777
 778         while (heredoclist) {
 779                 here = heredoclist;
 780                 heredoclist = here->next;
 781                 if (needprompt) {
 782                         setprompt(2);
 783                         needprompt = 0;
 784                 }
 785                 readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
 786                                 here->eofmark, here->striptabs);
 787                 n = (union node *)stalloc(sizeof (struct narg));
 788                 n->narg.type = NARG;
 789                 n->narg.next = NULL;
 790                 n->narg.text = wordtext;
 791                 n->narg.backquote = backquotelist;
 792                 here->here->nhere.doc = n;
 793         }
 794 }
 795
 796 static int
 797 peektoken(void)
 798 {
 799         int t;
 800
 801         t = readtoken();
 802         tokpushback++;
 803         return (t);
 804 }
 805
 806 static int
 807 readtoken(void)
 808 {
 809         int t;
 810         struct alias *ap;
 811 #ifdef DEBUG
 812         int alreadyseen = tokpushback;
 813 #endif
 814
 815         top:
 816         t = xxreadtoken();
 817
 818         /*
 819          * eat newlines
 820          */
 821         if (checkkwd & CHKNL) {
 822                 while (t == TNL) {
 823                         parseheredoc();
 824                         t = xxreadtoken();
 825                 }
 826         }
 827
 828         /*
 829          * check for keywords and aliases
 830          */
 831         if (t == TWORD && !quoteflag)
 832         {
 833                 const char * const *pp;
 834
 835                 if (checkkwd & CHKKWD)
 836                         for (pp = parsekwd; *pp; pp++) {
 837                                 if (**pp == *wordtext && equal(*pp, wordtext))
 838                                 {
 839                                         lasttoken = t = pp - parsekwd + KWDOFFSET;
 840                                         TRACE(("keyword %s recognized\n", tokname[t]));
 841                                         goto out;
 842                                 }
 843                         }
 844                 if (checkkwd & CHKALIAS &&
 845                     (ap = lookupalias(wordtext, 1)) != NULL) {
 846                         pushstring(ap->val, strlen(ap->val), ap);
 847                         goto top;
 848                 }
 849         }
 850 out:
 851         if (t != TNOT)
 852                 checkkwd = 0;
 853
 854 #ifdef DEBUG
 855         if (!alreadyseen)
 856             TRACE(("token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 857         else
 858             TRACE(("reread token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 859 #endif
 860         return (t);
 861 }
 862
 863
 864 /*
 865  * Read the next input token.
 866  * If the token is a word, we set backquotelist to the list of cmds in
 867  *      backquotes.  We set quoteflag to true if any part of the word was
 868  *      quoted.
 869  * If the token is TREDIR, then we set redirnode to a structure containing
 870  *      the redirection.
 871  * In all cases, the variable startlinno is set to the number of the line
 872  *      on which the token starts.
 873  *
 874  * [Change comment:  here documents and internal procedures]
 875  * [Readtoken shouldn't have any arguments.  Perhaps we should make the
 876  *  word parsing code into a separate routine.  In this case, readtoken
 877  *  doesn't need to have any internal procedures, but parseword does.
 878  *  We could also make parseoperator in essence the main routine, and
 879  *  have parseword (readtoken1?) handle both words and redirection.]
 880  */
 881
 882 #define RETURN(token)   return lasttoken = token
 883
 884 static int
 885 xxreadtoken(void)
 886 {
 887         int c;
 888
 889         if (tokpushback) {
 890                 tokpushback = 0;
 891                 return lasttoken;
 892         }
 893         if (needprompt) {
 894                 setprompt(2);
 895                 needprompt = 0;
 896         }
 897         startlinno = plinno;
 898         for (;;) {      /* until token or start of word found */
 899                 c = pgetc_macro();
 900                 switch (c) {
 901                 case ' ': case '\t':
 902                         continue;
 903                 case '#':
 904                         while ((c = pgetc()) != '\n' && c != PEOF);
 905                         pungetc();
 906                         continue;
 907                 case '\\':
 908                         if (pgetc() == '\n') {
 909                                 startlinno = ++plinno;
 910                                 if (doprompt)
 911                                         setprompt(2);
 912                                 else
 913                                         setprompt(0);
 914                                 continue;
 915                         }
 916                         pungetc();
 917                         goto breakloop;
 918                 case '\n':
 919                         plinno++;
 920                         needprompt = doprompt;
 921                         RETURN(TNL);
 922                 case PEOF:
 923                         RETURN(TEOF);
 924                 case '&':
 925                         if (pgetc() == '&')
 926                                 RETURN(TAND);
 927                         pungetc();
 928                         RETURN(TBACKGND);
 929                 case '|':
 930                         if (pgetc() == '|')
 931                                 RETURN(TOR);
 932                         pungetc();
 933                         RETURN(TPIPE);
 934                 case ';':
 935                         c = pgetc();
 936                         if (c == ';')
 937                                 RETURN(TENDCASE);
 938                         else if (c == '&')
 939                                 RETURN(TFALLTHRU);
 940                         pungetc();
 941                         RETURN(TSEMI);
 942                 case '(':
 943                         RETURN(TLP);
 944                 case ')':
 945                         RETURN(TRP);
 946                 default:
 947                         goto breakloop;
 948                 }
 949         }
 950 breakloop:
 951         return readtoken1(c, BASESYNTAX, NULL, 0);
 952 #undef RETURN
 953 }
 954
 955
 956 #define MAXNEST_STATIC 8
 957 struct tokenstate
 958 {
 959         const char *syntax; /* *SYNTAX */
 960         int parenlevel; /* levels of parentheses in arithmetic */
 961         enum tokenstate_category
 962         {
 963                 TSTATE_TOP,
 964                 TSTATE_VAR_OLD, /* ${var+-=?}, inherits dquotes */
 965                 TSTATE_VAR_NEW, /* other ${var...}, own dquote state */
 966                 TSTATE_ARITH
 967         } category;
 968 };
 969
 970
 971 /*
 972  * Called to parse command substitutions.
 973  */
 974
 975 static char *
 976 parsebackq(char *out, struct nodelist **pbqlist,
 977     int oldstyle, int dblquote, int quoted)
 978 {
 979         struct nodelist **nlpp;
 980         union node *n;
 981         char *volatile str;
 982         struct jmploc jmploc;
 983         struct jmploc *const savehandler = handler;
 984         int savelen;
 985         int saveprompt;
 986         const int bq_startlinno = plinno;
 987         char *volatile ostr = NULL;
 988         struct parsefile *const savetopfile = getcurrentfile();
 989         struct heredoc *const saveheredoclist = heredoclist;
 990         struct heredoc *here;
 991
 992         str = NULL;
 993         if (setjmp(jmploc.loc)) {
 994                 popfilesupto(savetopfile);
 995                 if (str)
 996                         ckfree(str);
 997                 if (ostr)
 998                         ckfree(ostr);
 999                 heredoclist = saveheredoclist;
1000                 handler = savehandler;
1001                 if (exception == EXERROR) {
1002                         startlinno = bq_startlinno;
1003                         synerror("Error in command substitution");
1004                 }
1005                 longjmp(handler->loc, 1);
1006         }
1007         INTOFF;
1008         savelen = out - stackblock();
1009         if (savelen > 0) {
1010                 str = ckmalloc(savelen);
1011                 memcpy(str, stackblock(), savelen);
1012         }
1013         handler = &jmploc;
1014         heredoclist = NULL;
1015         INTON;
1016         if (oldstyle) {
1017                 /*
1018                  * We must read until the closing backquote, giving special
1019                  * treatment to some slashes, and then push the string and
1020                  * reread it as input, interpreting it normally.
1021                  */
1022                 char *oout;
1023                 int c, olen;
1024
1025                 STARTSTACKSTR(oout);
1026                 for (;;) {
1027                         if (needprompt) {
1028                                 setprompt(2);
1029                                 needprompt = 0;
1030                         }
1031                         CHECKSTRSPACE(2, oout);
1032                         switch (c = pgetc()) {
1033                         case '`':
1034                                 goto done;
1035
1036                         case '\\':
1037                                 if ((c = pgetc()) == '\n') {
1038                                         plinno++;
1039                                         if (doprompt)
1040                                                 setprompt(2);
1041                                         else
1042                                                 setprompt(0);
1043                                         /*
1044                                          * If eating a newline, avoid putting
1045                                          * the newline into the new character
1046                                          * stream (via the USTPUTC after the
1047                                          * switch).
1048                                          */
1049                                         continue;
1050                                 }
1051                                 if (c != '\\' && c != '`' && c != '$'
1052                                     && (!dblquote || c != '"'))
1053                                         USTPUTC('\\', oout);
1054                                 break;
1055
1056                         case '\n':
1057                                 plinno++;
1058                                 needprompt = doprompt;
1059                                 break;
1060
1061                         case PEOF:
1062                                 startlinno = plinno;
1063                                 synerror("EOF in backquote substitution");
1064                                 break;
1065
1066                         default:
1067                                 break;
1068                         }
1069                         USTPUTC(c, oout);
1070                 }
1071 done:
1072                 USTPUTC('\0', oout);
1073                 olen = oout - stackblock();
1074                 INTOFF;
1075                 ostr = ckmalloc(olen);
1076                 memcpy(ostr, stackblock(), olen);
1077                 setinputstring(ostr, 1);
1078                 INTON;
1079         }
1080         nlpp = pbqlist;
1081         while (*nlpp)
1082                 nlpp = &(*nlpp)->next;
1083         *nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
1084         (*nlpp)->next = NULL;
1085
1086         if (oldstyle) {
1087                 saveprompt = doprompt;
1088                 doprompt = 0;
1089         }
1090
1091         n = list(0, oldstyle);
1092
1093         if (oldstyle)
1094                 doprompt = saveprompt;
1095         else {
1096                 if (readtoken() != TRP)
1097                         synexpect(TRP);
1098         }
1099
1100         (*nlpp)->n = n;
1101         if (oldstyle) {
1102                 /*
1103                  * Start reading from old file again, ignoring any pushed back
1104                  * tokens left from the backquote parsing
1105                  */
1106                 popfile();
1107                 tokpushback = 0;
1108         }
1109         STARTSTACKSTR(out);
1110         CHECKSTRSPACE(savelen + 1, out);
1111         INTOFF;
1112         if (str) {
1113                 memcpy(out, str, savelen);
1114                 STADJUST(savelen, out);
1115                 ckfree(str);
1116                 str = NULL;
1117         }
1118         if (ostr) {
1119                 ckfree(ostr);
1120                 ostr = NULL;
1121         }
1122         here = saveheredoclist;
1123         if (here != NULL) {
1124                 while (here->next != NULL)
1125                         here = here->next;
1126                 here->next = heredoclist;
1127                 heredoclist = saveheredoclist;
1128         }
1129         handler = savehandler;
1130         INTON;
1131         if (quoted)
1132                 USTPUTC(CTLBACKQ | CTLQUOTE, out);
1133         else
1134                 USTPUTC(CTLBACKQ, out);
1135         return out;
1136 }
1137
1138
1139 /*
1140  * Called to parse a backslash escape sequence inside $'...'.
1141  * The backslash has already been read.
1142  */
1143 static char *
1144 readcstyleesc(char *out)
1145 {
1146         int c, v, i, n;
1147
1148         c = pgetc();
1149         switch (c) {
1150         case '\0':
1151                 synerror("Unterminated quoted string");
1152         case '\n':
1153                 plinno++;
1154                 if (doprompt)
1155                         setprompt(2);
1156                 else
1157                         setprompt(0);
1158                 return out;
1159         case '\\':
1160         case '\'':
1161         case '"':
1162                 v = c;
1163                 break;
1164         case 'a': v = '\a'; break;
1165         case 'b': v = '\b'; break;
1166         case 'e': v = '\033'; break;
1167         case 'f': v = '\f'; break;
1168         case 'n': v = '\n'; break;
1169         case 'r': v = '\r'; break;
1170         case 't': v = '\t'; break;
1171         case 'v': v = '\v'; break;
1172         case 'x':
1173                   v = 0;
1174                   for (;;) {
1175                           c = pgetc();
1176                           if (c >= '0' && c <= '9')
1177                                   v = (v << 4) + c - '0';
1178                           else if (c >= 'A' && c <= 'F')
1179                                   v = (v << 4) + c - 'A' + 10;
1180                           else if (c >= 'a' && c <= 'f')
1181                                   v = (v << 4) + c - 'a' + 10;
1182                           else
1183                                   break;
1184                   }
1185                   pungetc();
1186                   break;
1187         case '0': case '1': case '2': case '3':
1188         case '4': case '5': case '6': case '7':
1189                   v = c - '0';
1190                   c = pgetc();
1191                   if (c >= '0' && c <= '7') {
1192                           v <<= 3;
1193                           v += c - '0';
1194                           c = pgetc();
1195                           if (c >= '0' && c <= '7') {
1196                                   v <<= 3;
1197                                   v += c - '0';
1198                           } else
1199                                   pungetc();
1200                   } else
1201                           pungetc();
1202                   break;
1203         case 'c':
1204                   c = pgetc();
1205                   if (c < 0x3f || c > 0x7a || c == 0x60)
1206                           synerror("Bad escape sequence");
1207                   if (c == '\\' && pgetc() != '\\')
1208                           synerror("Bad escape sequence");
1209                   if (c == '?')
1210                           v = 127;
1211                   else
1212                           v = c & 0x1f;
1213                   break;
1214         case 'u':
1215         case 'U':
1216                   n = c == 'U' ? 8 : 4;
1217                   v = 0;
1218                   for (i = 0; i < n; i++) {
1219                           c = pgetc();
1220                           if (c >= '0' && c <= '9')
1221                                   v = (v << 4) + c - '0';
1222                           else if (c >= 'A' && c <= 'F')
1223                                   v = (v << 4) + c - 'A' + 10;
1224                           else if (c >= 'a' && c <= 'f')
1225                                   v = (v << 4) + c - 'a' + 10;
1226                           else
1227                                   synerror("Bad escape sequence");
1228                   }
1229                   if (v == 0 || (v >= 0xd800 && v <= 0xdfff))
1230                           synerror("Bad escape sequence");
1231                   /* We really need iconv here. */
1232                   if (initial_localeisutf8 && v > 127) {
1233                           CHECKSTRSPACE(4, out);
1234                           /*
1235                            * We cannot use wctomb() as the locale may have
1236                            * changed.
1237                            */
1238                           if (v <= 0x7ff) {
1239                                   USTPUTC(0xc0 | v >> 6, out);
1240                                   USTPUTC(0x80 | (v & 0x3f), out);
1241                                   return out;
1242                           } else if (v <= 0xffff) {
1243                                   USTPUTC(0xe0 | v >> 12, out);
1244                                   USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
1245                                   USTPUTC(0x80 | (v & 0x3f), out);
1246                                   return out;
1247                           } else if (v <= 0x10ffff) {
1248                                   USTPUTC(0xf0 | v >> 18, out);
1249                                   USTPUTC(0x80 | ((v >> 12) & 0x3f), out);
1250                                   USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
1251                                   USTPUTC(0x80 | (v & 0x3f), out);
1252                                   return out;
1253                           }
1254                   }
1255                   if (v > 127)
1256                           v = '?';
1257                   break;
1258         default:
1259                   synerror("Bad escape sequence");
1260         }
1261         v = (char)v;
1262         /*
1263          * We can't handle NUL bytes.
1264          * POSIX says we should skip till the closing quote.
1265          */
1266         if (v == '\0') {
1267                 while ((c = pgetc()) != '\'') {
1268                         if (c == '\\')
1269                                 c = pgetc();
1270                         if (c == PEOF)
1271                                 synerror("Unterminated quoted string");
1272                 }
1273                 pungetc();
1274                 return out;
1275         }
1276         if (SQSYNTAX[v] == CCTL)
1277                 USTPUTC(CTLESC, out);
1278         USTPUTC(v, out);
1279         return out;
1280 }
1281
1282
1283 /*
1284  * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
1285  * is not NULL, read a here document.  In the latter case, eofmark is the
1286  * word which marks the end of the document and striptabs is true if
1287  * leading tabs should be stripped from the document.  The argument firstc
1288  * is the first character of the input token or document.
1289  *
1290  * Because C does not have internal subroutines, I have simulated them
1291  * using goto's to implement the subroutine linkage.  The following macros
1292  * will run code that appears at the end of readtoken1.
1293  */
1294
1295 #define CHECKEND()      {goto checkend; checkend_return:;}
1296 #define PARSEREDIR()    {goto parseredir; parseredir_return:;}
1297 #define PARSESUB()      {goto parsesub; parsesub_return:;}
1298 #define PARSEARITH()    {goto parsearith; parsearith_return:;}
1299
1300 static int
1301 readtoken1(int firstc, char const *initialsyntax, char *eofmark, int striptabs)
1302 {
1303         int c = firstc;
1304         char * volatile out;
1305         int len;
1306         char line[EOFMARKLEN + 1];
1307         struct nodelist *bqlist;
1308         volatile int quotef;
1309         int newvarnest;
1310         int level;
1311         int synentry;
1312         struct tokenstate state_static[MAXNEST_STATIC];
1313         int maxnest = MAXNEST_STATIC;
1314         struct tokenstate *state = state_static;
1315         int sqiscstyle = 0;
1316
1317         startlinno = plinno;
1318         quotef = 0;
1319         bqlist = NULL;
1320         newvarnest = 0;
1321         level = 0;
1322         state[level].syntax = initialsyntax;
1323         state[level].parenlevel = 0;
1324         state[level].category = TSTATE_TOP;
1325
1326         STARTSTACKSTR(out);
1327         loop: { /* for each line, until end of word */
1328                 CHECKEND();     /* set c to PEOF if at end of here document */
1329                 for (;;) {      /* until end of line or end of word */
1330                         CHECKSTRSPACE(4, out);  /* permit 4 calls to USTPUTC */
1331
1332                         synentry = state[level].syntax[c];
1333
1334                         switch(synentry) {
1335                         case CNL:       /* '\n' */
1336                                 if (state[level].syntax == BASESYNTAX)
1337                                         goto endword;   /* exit outer loop */
1338                                 USTPUTC(c, out);
1339                                 plinno++;
1340                                 if (doprompt)
1341                                         setprompt(2);
1342                                 else
1343                                         setprompt(0);
1344                                 c = pgetc();
1345                                 goto loop;              /* continue outer loop */
1346                         case CSBACK:
1347                                 if (sqiscstyle) {
1348                                         out = readcstyleesc(out);
1349                                         break;
1350                                 }
1351                                 /* FALLTHROUGH */
1352                         case CWORD:
1353                                 USTPUTC(c, out);
1354                                 break;
1355                         case CCTL:
1356                                 if (eofmark == NULL || initialsyntax != SQSYNTAX)
1357                                         USTPUTC(CTLESC, out);
1358                                 USTPUTC(c, out);
1359                                 break;
1360                         case CBACK:     /* backslash */
1361                                 c = pgetc();
1362                                 if (c == PEOF) {
1363                                         USTPUTC('\\', out);
1364                                         pungetc();
1365                                 } else if (c == '\n') {
1366                                         plinno++;
1367                                         if (doprompt)
1368                                                 setprompt(2);
1369                                         else
1370                                                 setprompt(0);
1371                                 } else {
1372                                         if (state[level].syntax == DQSYNTAX &&
1373                                             c != '\\' && c != '`' && c != '$' &&
1374                                             (c != '"' || (eofmark != NULL &&
1375                                                 newvarnest == 0)) &&
1376                                             (c != '}' || state[level].category != TSTATE_VAR_OLD))
1377                                                 USTPUTC('\\', out);
1378                                         if ((eofmark == NULL ||
1379                                             newvarnest > 0) &&
1380                                             state[level].syntax == BASESYNTAX)
1381                                                 USTPUTC(CTLQUOTEMARK, out);
1382                                         if (SQSYNTAX[c] == CCTL)
1383                                                 USTPUTC(CTLESC, out);
1384                                         USTPUTC(c, out);
1385                                         if ((eofmark == NULL ||
1386                                             newvarnest > 0) &&
1387                                             state[level].syntax == BASESYNTAX &&
1388                                             state[level].category == TSTATE_VAR_OLD)
1389                                                 USTPUTC(CTLQUOTEEND, out);
1390                                         quotef++;
1391                                 }
1392                                 break;
1393                         case CSQUOTE:
1394                                 USTPUTC(CTLQUOTEMARK, out);
1395                                 state[level].syntax = SQSYNTAX;
1396                                 sqiscstyle = 0;
1397                                 break;
1398                         case CDQUOTE:
1399                                 USTPUTC(CTLQUOTEMARK, out);
1400                                 state[level].syntax = DQSYNTAX;
1401                                 break;
1402                         case CENDQUOTE:
1403                                 if (eofmark != NULL && newvarnest == 0)
1404                                         USTPUTC(c, out);
1405                                 else {
1406                                         if (state[level].category == TSTATE_VAR_OLD)
1407                                                 USTPUTC(CTLQUOTEEND, out);
1408                                         state[level].syntax = BASESYNTAX;
1409                                         quotef++;
1410                                 }
1411                                 break;
1412                         case CVAR:      /* '$' */
1413                                 PARSESUB();             /* parse substitution */
1414                                 break;
1415                         case CENDVAR:   /* '}' */
1416                                 if (level > 0 &&
1417                                     ((state[level].category == TSTATE_VAR_OLD &&
1418                                       state[level].syntax ==
1419                                       state[level - 1].syntax) ||
1420                                     (state[level].category == TSTATE_VAR_NEW &&
1421                                      state[level].syntax == BASESYNTAX))) {
1422                                         if (state[level].category == TSTATE_VAR_NEW)
1423                                                 newvarnest--;
1424                                         level--;
1425                                         USTPUTC(CTLENDVAR, out);
1426                                 } else {
1427                                         USTPUTC(c, out);
1428                                 }
1429                                 break;
1430                         case CLP:       /* '(' in arithmetic */
1431                                 state[level].parenlevel++;
1432                                 USTPUTC(c, out);
1433                                 break;
1434                         case CRP:       /* ')' in arithmetic */
1435                                 if (state[level].parenlevel > 0) {
1436                                         USTPUTC(c, out);
1437                                         --state[level].parenlevel;
1438                                 } else {
1439                                         if (pgetc() == ')') {
1440                                                 if (level > 0 &&
1441                                                     state[level].category == TSTATE_ARITH) {
1442                                                         level--;
1443                                                         USTPUTC(CTLENDARI, out);
1444                                                 } else
1445                                                         USTPUTC(')', out);
1446                                         } else {
1447                                                 /*
1448                                                  * unbalanced parens
1449                                                  *  (don't 2nd guess - no error)
1450                                                  */
1451                                                 pungetc();
1452                                                 USTPUTC(')', out);
1453                                         }
1454                                 }
1455                                 break;
1456                         case CBQUOTE:   /* '`' */
1457                                 out = parsebackq(out, &bqlist, 1,
1458                                     state[level].syntax == DQSYNTAX &&
1459                                     (eofmark == NULL || newvarnest > 0),
1460                                     state[level].syntax == DQSYNTAX || state[level].syntax == ARISYNTAX);
1461                                 break;
1462                         case CEOF:
1463                                 goto endword;           /* exit outer loop */
1464                         case CIGN:
1465                                 break;
1466                         default:
1467                                 if (level == 0)
1468                                         goto endword;   /* exit outer loop */
1469                                 USTPUTC(c, out);
1470                         }
1471                         c = pgetc_macro();
1472                 }
1473         }
1474 endword:
1475         if (state[level].syntax == ARISYNTAX)
1476                 synerror("Missing '))'");
1477         if (state[level].syntax != BASESYNTAX && eofmark == NULL)
1478                 synerror("Unterminated quoted string");
1479         if (state[level].category == TSTATE_VAR_OLD ||
1480             state[level].category == TSTATE_VAR_NEW) {
1481                 startlinno = plinno;
1482                 synerror("Missing '}'");
1483         }
1484         if (state != state_static)
1485                 parser_temp_free_upto(state);
1486         USTPUTC('\0', out);
1487         len = out - stackblock();
1488         out = stackblock();
1489         if (eofmark == NULL) {
1490                 if ((c == '>' || c == '<')
1491                  && quotef == 0
1492                  && len <= 2
1493                  && (*out == '\0' || is_digit(*out))) {
1494                         PARSEREDIR();
1495                         return lasttoken = TREDIR;
1496                 } else {
1497                         pungetc();
1498                 }
1499         }
1500         quoteflag = quotef;
1501         backquotelist = bqlist;
1502         grabstackblock(len);
1503         wordtext = out;
1504         return lasttoken = TWORD;
1505 /* end of readtoken routine */
1506
1507
1508 /*
1509  * Check to see whether we are at the end of the here document.  When this
1510  * is called, c is set to the first character of the next input line.  If
1511  * we are at the end of the here document, this routine sets the c to PEOF.
1512  */
1513
1514 checkend: {
1515         if (eofmark) {
1516                 if (striptabs) {
1517                         while (c == '\t')
1518                                 c = pgetc();
1519                 }
1520                 if (c == *eofmark) {
1521                         if (pfgets(line, sizeof line) != NULL) {
1522                                 char *p, *q;
1523
1524                                 p = line;
1525                                 for (q = eofmark + 1 ; *q && *p == *q ; p++, q++);
1526                                 if ((*p == '\0' || *p == '\n') && *q == '\0') {
1527                                         c = PEOF;
1528                                         if (*p == '\n') {
1529                                                 plinno++;
1530                                                 needprompt = doprompt;
1531                                         }
1532                                 } else {
1533                                         pushstring(line, strlen(line), NULL);
1534                                 }
1535                         }
1536                 }
1537         }
1538         goto checkend_return;
1539 }
1540
1541
1542 /*
1543  * Parse a redirection operator.  The variable "out" points to a string
1544  * specifying the fd to be redirected.  The variable "c" contains the
1545  * first character of the redirection operator.
1546  */
1547
1548 parseredir: {
1549         char fd = *out;
1550         union node *np;
1551
1552         np = (union node *)stalloc(sizeof (struct nfile));
1553         if (c == '>') {
1554                 np->nfile.fd = 1;
1555                 c = pgetc();
1556                 if (c == '>')
1557                         np->type = NAPPEND;
1558                 else if (c == '&')
1559                         np->type = NTOFD;
1560                 else if (c == '|')
1561                         np->type = NCLOBBER;
1562                 else {
1563                         np->type = NTO;
1564                         pungetc();
1565                 }
1566         } else {        /* c == '<' */
1567                 np->nfile.fd = 0;
1568                 c = pgetc();
1569                 if (c == '<') {
1570                         if (sizeof (struct nfile) != sizeof (struct nhere)) {
1571                                 np = (union node *)stalloc(sizeof (struct nhere));
1572                                 np->nfile.fd = 0;
1573                         }
1574                         np->type = NHERE;
1575                         heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
1576                         heredoc->here = np;
1577                         if ((c = pgetc()) == '-') {
1578                                 heredoc->striptabs = 1;
1579                         } else {
1580                                 heredoc->striptabs = 0;
1581                                 pungetc();
1582                         }
1583                 } else if (c == '&')
1584                         np->type = NFROMFD;
1585                 else if (c == '>')
1586                         np->type = NFROMTO;
1587                 else {
1588                         np->type = NFROM;
1589                         pungetc();
1590                 }
1591         }
1592         if (fd != '\0')
1593                 np->nfile.fd = digit_val(fd);
1594         redirnode = np;
1595         goto parseredir_return;
1596 }
1597
1598
1599 /*
1600  * Parse a substitution.  At this point, we have read the dollar sign
1601  * and nothing else.
1602  */
1603
1604 parsesub: {
1605         char buf[10];
1606         int subtype;
1607         int typeloc;
1608         int flags;
1609         char *p;
1610         static const char types[] = "}-+?=";
1611         int bracketed_name = 0; /* used to handle ${[0-9]*} variables */
1612         int linno;
1613         int length;
1614         int c1;
1615
1616         c = pgetc();
1617         if (c == '(') { /* $(command) or $((arith)) */
1618                 if (pgetc() == '(') {
1619                         PARSEARITH();
1620                 } else {
1621                         pungetc();
1622                         out = parsebackq(out, &bqlist, 0,
1623                             state[level].syntax == DQSYNTAX &&
1624                             (eofmark == NULL || newvarnest > 0),
1625                             state[level].syntax == DQSYNTAX ||
1626                             state[level].syntax == ARISYNTAX);
1627                 }
1628         } else if (c == '{' || is_name(c) || is_special(c)) {
1629                 USTPUTC(CTLVAR, out);
1630                 typeloc = out - stackblock();
1631                 USTPUTC(VSNORMAL, out);
1632                 subtype = VSNORMAL;
1633                 flags = 0;
1634                 if (c == '{') {
1635                         bracketed_name = 1;
1636                         c = pgetc();
1637                         subtype = 0;
1638                 }
1639 varname:
1640                 if (!is_eof(c) && is_name(c)) {
1641                         length = 0;
1642                         do {
1643                                 STPUTC(c, out);
1644                                 c = pgetc();
1645                                 length++;
1646                         } while (!is_eof(c) && is_in_name(c));
1647                         if (length == 6 &&
1648                             strncmp(out - length, "LINENO", length) == 0) {
1649                                 /* Replace the variable name with the
1650                                  * current line number. */
1651                                 linno = plinno;
1652                                 if (funclinno != 0)
1653                                         linno -= funclinno - 1;
1654                                 snprintf(buf, sizeof(buf), "%d", linno);
1655                                 STADJUST(-6, out);
1656                                 STPUTS(buf, out);
1657                                 flags |= VSLINENO;
1658                         }
1659                 } else if (is_digit(c)) {
1660                         if (bracketed_name) {
1661                                 do {
1662                                         STPUTC(c, out);
1663                                         c = pgetc();
1664                                 } while (is_digit(c));
1665                         } else {
1666                                 STPUTC(c, out);
1667                                 c = pgetc();
1668                         }
1669                 } else if (is_special(c)) {
1670                         c1 = c;
1671                         c = pgetc();
1672                         if (subtype == 0 && c1 == '#') {
1673                                 subtype = VSLENGTH;
1674                                 if (strchr(types, c) == NULL && c != ':' &&
1675                                     c != '#' && c != '%')
1676                                         goto varname;
1677                                 c1 = c;
1678                                 c = pgetc();
1679                                 if (c1 != '}' && c == '}') {
1680                                         pungetc();
1681                                         c = c1;
1682                                         goto varname;
1683                                 }
1684                                 pungetc();
1685                                 c = c1;
1686                                 c1 = '#';
1687                                 subtype = 0;
1688                         }
1689                         USTPUTC(c1, out);
1690                 } else {
1691                         subtype = VSERROR;
1692                         if (c == '}')
1693                                 pungetc();
1694                         else if (c == '\n' || c == PEOF)
1695                                 synerror("Unexpected end of line in substitution");
1696                         else
1697                                 USTPUTC(c, out);
1698                 }
1699                 if (subtype == 0) {
1700                         switch (c) {
1701                         case ':':
1702                                 flags |= VSNUL;
1703                                 c = pgetc();
1704                                 /*FALLTHROUGH*/
1705                         default:
1706                                 p = strchr(types, c);
1707                                 if (p == NULL) {
1708                                         if (c == '\n' || c == PEOF)
1709                                                 synerror("Unexpected end of line in substitution");
1710                                         if (flags == VSNUL)
1711                                                 STPUTC(':', out);
1712                                         STPUTC(c, out);
1713                                         subtype = VSERROR;
1714                                 } else
1715                                         subtype = p - types + VSNORMAL;
1716                                 break;
1717                         case '%':
1718                         case '#':
1719                                 {
1720                                         int cc = c;
1721                                         subtype = c == '#' ? VSTRIMLEFT :
1722                                                              VSTRIMRIGHT;
1723                                         c = pgetc();
1724                                         if (c == cc)
1725                                                 subtype++;
1726                                         else
1727                                                 pungetc();
1728                                         break;
1729                                 }
1730                         }
1731                 } else if (subtype != VSERROR) {
1732                         if (subtype == VSLENGTH && c != '}')
1733                                 subtype = VSERROR;
1734                         pungetc();
1735                 }
1736                 STPUTC('=', out);
1737                 if (state[level].syntax == DQSYNTAX ||
1738                     state[level].syntax == ARISYNTAX)
1739                         flags |= VSQUOTE;
1740                 *(stackblock() + typeloc) = subtype | flags;
1741                 if (subtype != VSNORMAL) {
1742                         if (level + 1 >= maxnest) {
1743                                 maxnest *= 2;
1744                                 if (state == state_static) {
1745                                         state = parser_temp_alloc(
1746                                             maxnest * sizeof(*state));
1747                                         memcpy(state, state_static,
1748                                             MAXNEST_STATIC * sizeof(*state));
1749                                 } else
1750                                         state = parser_temp_realloc(state,
1751                                             maxnest * sizeof(*state));
1752                         }
1753                         level++;
1754                         state[level].parenlevel = 0;
1755                         if (subtype == VSMINUS || subtype == VSPLUS ||
1756                             subtype == VSQUESTION || subtype == VSASSIGN) {
1757                                 /*
1758                                  * For operators that were in the Bourne shell,
1759                                  * inherit the double-quote state.
1760                                  */
1761                                 state[level].syntax = state[level - 1].syntax;
1762                                 state[level].category = TSTATE_VAR_OLD;
1763                         } else {
1764                                 /*
1765                                  * The other operators take a pattern,
1766                                  * so go to BASESYNTAX.
1767                                  * Also, ' and " are now special, even
1768                                  * in here documents.
1769                                  */
1770                                 state[level].syntax = BASESYNTAX;
1771                                 state[level].category = TSTATE_VAR_NEW;
1772                                 newvarnest++;
1773                         }
1774                 }
1775         } else if (c == '\'' && state[level].syntax == BASESYNTAX) {
1776                 /* $'cstylequotes' */
1777                 USTPUTC(CTLQUOTEMARK, out);
1778                 state[level].syntax = SQSYNTAX;
1779                 sqiscstyle = 1;
1780         } else {
1781                 USTPUTC('$', out);
1782                 pungetc();
1783         }
1784         goto parsesub_return;
1785 }
1786
1787
1788 /*
1789  * Parse an arithmetic expansion (indicate start of one and set state)
1790  */
1791 parsearith: {
1792
1793         if (level + 1 >= maxnest) {
1794                 maxnest *= 2;
1795                 if (state == state_static) {
1796                         state = parser_temp_alloc(
1797                             maxnest * sizeof(*state));
1798                         memcpy(state, state_static,
1799                             MAXNEST_STATIC * sizeof(*state));
1800                 } else
1801                         state = parser_temp_realloc(state,
1802                             maxnest * sizeof(*state));
1803         }
1804         level++;
1805         state[level].syntax = ARISYNTAX;
1806         state[level].parenlevel = 0;
1807         state[level].category = TSTATE_ARITH;
1808         USTPUTC(CTLARI, out);
1809         if (state[level - 1].syntax == DQSYNTAX)
1810                 USTPUTC('"',out);
1811         else
1812                 USTPUTC(' ',out);
1813         goto parsearith_return;
1814 }
1815
1816 } /* end of readtoken */
1817
1818
1819
1820 #ifdef mkinit
1821 RESET {
1822         tokpushback = 0;
1823         checkkwd = 0;
1824 }
1825 #endif
1826
1827 /*
1828  * Returns true if the text contains nothing to expand (no dollar signs
1829  * or backquotes).
1830  */
1831
1832 static int
1833 noexpand(char *text)
1834 {
1835         char *p;
1836         char c;
1837
1838         p = text;
1839         while ((c = *p++) != '\0') {
1840                 if ( c == CTLQUOTEMARK)
1841                         continue;
1842                 if (c == CTLESC)
1843                         p++;
1844                 else if (BASESYNTAX[(int)c] == CCTL)
1845                         return 0;
1846         }
1847         return 1;
1848 }
1849
1850
1851 /*
1852  * Return true if the argument is a legal variable name (a letter or
1853  * underscore followed by zero or more letters, underscores, and digits).
1854  */
1855
1856 int
1857 goodname(const char *name)
1858 {
1859         const char *p;
1860
1861         p = name;
1862         if (! is_name(*p))
1863                 return 0;
1864         while (*++p) {
1865                 if (! is_in_name(*p))
1866                         return 0;
1867         }
1868         return 1;
1869 }
1870
1871
1872 int
1873 isassignment(const char *p)
1874 {
1875         if (!is_name(*p))
1876                 return 0;
1877         p++;
1878         for (;;) {
1879                 if (*p == '=')
1880                         return 1;
1881                 else if (!is_in_name(*p))
1882                         return 0;
1883                 p++;
1884         }
1885 }
1886
1887
1888 /*
1889  * Called when an unexpected token is read during the parse.  The argument
1890  * is the token that is expected, or -1 if more than one type of token can
1891  * occur at this point.
1892  */
1893
1894 static void
1895 synexpect(int token)
1896 {
1897         char msg[64];
1898
1899         if (token >= 0) {
1900                 fmtstr(msg, 64, "%s unexpected (expecting %s)",
1901                         tokname[lasttoken], tokname[token]);
1902         } else {
1903                 fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
1904         }
1905         synerror(msg);
1906 }
1907
1908
1909 static void
1910 synerror(const char *msg)
1911 {
1912         if (commandname)
1913                 outfmt(out2, "%s: %d: ", commandname, startlinno);
1914         outfmt(out2, "Syntax error: %s\n", msg);
1915         error(NULL);
1916 }
1917
1918 static void
1919 setprompt(int which)
1920 {
1921         whichprompt = which;
1922
1923 #ifndef NO_HISTORY
1924         if (!el)
1925 #endif
1926         {
1927                 out2str(getprompt(NULL));
1928                 flushout(out2);
1929         }
1930 }
1931
1932 /*
1933  * called by editline -- any expansions to the prompt
1934  *    should be added here.
1935  */
1936 const char *
1937 getprompt(void *unused __unused)
1938 {
1939         static char ps[PROMPTLEN];
1940         const char *fmt;
1941         const char *pwd;
1942         int i, trim;
1943
1944         /*
1945          * Select prompt format.
1946          */
1947         switch (whichprompt) {
1948         case 0:
1949                 fmt = "";
1950                 break;
1951         case 1:
1952                 fmt = ps1val();
1953                 break;
1954         case 2:
1955                 fmt = ps2val();
1956                 break;
1957         default:
1958                 return "??";
1959         }
1960
1961         /*
1962          * Format prompt string.
1963          */
1964         for (i = 0; (i < 127) && (*fmt != '\0'); i++, fmt++)
1965                 if (*fmt == '\\')
1966                         switch (*++fmt) {
1967
1968                                 /*
1969                                  * Hostname.
1970                                  *
1971                                  * \h specifies just the local hostname,
1972                                  * \H specifies fully-qualified hostname.
1973                                  */
1974                         case 'h':
1975                         case 'H':
1976                                 ps[i] = '\0';
1977                                 gethostname(&ps[i], PROMPTLEN - i);
1978                                 /* Skip to end of hostname. */
1979                                 trim = (*fmt == 'h') ? '.' : '\0';
1980                                 while ((ps[i+1] != '\0') && (ps[i+1] != trim))
1981                                         i++;
1982                                 break;
1983
1984                                 /*
1985                                  * Working directory.
1986                                  *
1987                                  * \W specifies just the final component,
1988                                  * \w specifies the entire path.
1989                                  */
1990                         case 'W':
1991                         case 'w':
1992                                 pwd = lookupvar("PWD");
1993                                 if (pwd == NULL)
1994                                         pwd = "?";
1995                                 if (*fmt == 'W' &&
1996                                     *pwd == '/' && pwd[1] != '\0')
1997                                         strlcpy(&ps[i], strrchr(pwd, '/') + 1,
1998                                             PROMPTLEN - i);
1999                                 else
2000                                         strlcpy(&ps[i], pwd, PROMPTLEN - i);
2001                                 /* Skip to end of path. */
2002                                 while (ps[i + 1] != '\0')
2003                                         i++;
2004                                 break;
2005
2006                                 /*
2007                                  * Superuser status.
2008                                  *
2009                                  * '$' for normal users, '#' for root.
2010                                  */
2011                         case '$':
2012                                 ps[i] = (geteuid() != 0) ? '$' : '#';
2013                                 break;
2014
2015                                 /*
2016                                  * A literal \.
2017                                  */
2018                         case '\\':
2019                                 ps[i] = '\\';
2020                                 break;
2021
2022                                 /*
2023                                  * Emit unrecognized formats verbatim.
2024                                  */
2025                         default:
2026                                 ps[i++] = '\\';
2027                                 ps[i] = *fmt;
2028                                 break;
2029                         }
2030                 else
2031                         ps[i] = *fmt;
2032         ps[i] = '\0';
2033         return (ps);
2034 }
2035
2036
2037 const char *
2038 expandstr(char *ps)
2039 {
2040         union node n;
2041         struct jmploc jmploc;
2042         struct jmploc *const savehandler = handler;
2043         const int saveprompt = doprompt;
2044         struct parsefile *const savetopfile = getcurrentfile();
2045         struct parser_temp *const saveparser_temp = parser_temp;
2046         const char *result = NULL;
2047
2048         if (!setjmp(jmploc.loc)) {
2049                 handler = &jmploc;
2050                 parser_temp = NULL;
2051                 setinputstring(ps, 1);
2052                 doprompt = 0;
2053                 readtoken1(pgetc(), DQSYNTAX, __DECONST(char *, "\n\n"), 0);
2054                 if (backquotelist != NULL)
2055                         error("Command substitution not allowed here");
2056
2057                 n.narg.type = NARG;
2058                 n.narg.next = NULL;
2059                 n.narg.text = wordtext;
2060                 n.narg.backquote = backquotelist;
2061
2062                 expandarg(&n, NULL, 0);
2063                 result = stackblock();
2064                 INTOFF;
2065         }
2066         handler = savehandler;
2067         doprompt = saveprompt;
2068         popfilesupto(savetopfile);
2069         if (parser_temp != saveparser_temp) {
2070                 parser_temp_free_all();
2071                 parser_temp = saveparser_temp;
2072         }
2073         if (result != NULL) {
2074                 INTON;
2075         } else if (exception == EXINT)
2076                 raise(SIGINT);
2077         return result;
2078 }