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  * @(#)parser.c 8.7 (Berkeley) 5/16/95
  33  * $FreeBSD: head/bin/sh/parser.c 245382 2013-01-13 19:26:33Z jilles $
  34  */
  35
  36 #include <stdio.h>
  37 #include <stdlib.h>
  38 #include <unistd.h>
  39
  40 #include "shell.h"
  41 #include "parser.h"
  42 #include "nodes.h"
  43 #include "expand.h"     /* defines rmescapes() */
  44 #include "syntax.h"
  45 #include "options.h"
  46 #include "input.h"
  47 #include "output.h"
  48 #include "var.h"
  49 #include "error.h"
  50 #include "memalloc.h"
  51 #include "mystring.h"
  52 #include "alias.h"
  53 #include "show.h"
  54 #include "eval.h"
  55 #include "exec.h"       /* to check for special builtins */
  56 #ifndef NO_HISTORY
  57 #include "myhistedit.h"
  58 #endif
  59
  60 /*
  61  * Shell command parser.
  62  */
  63
  64 #define EOFMARKLEN      79
  65 #define PROMPTLEN       128
  66
  67 /* values of checkkwd variable */
  68 #define CHKALIAS        0x1
  69 #define CHKKWD          0x2
  70 #define CHKNL           0x4
  71
  72 /* values returned by readtoken */
  73 #include "token.h"
  74
  75
  76
  77 struct heredoc {
  78         struct heredoc *next;   /* next here document in list */
  79         union node *here;               /* redirection node */
  80         char *eofmark;          /* string indicating end of input */
  81         int striptabs;          /* if set, strip leading tabs */
  82 };
  83
  84 struct parser_temp {
  85         struct parser_temp *next;
  86         void *data;
  87 };
  88
  89
  90 static struct heredoc *heredoclist;     /* list of here documents to read */
  91 static int doprompt;            /* if set, prompt the user */
  92 static int needprompt;          /* true if interactive and at start of line */
  93 static int lasttoken;           /* last token read */
  94 MKINIT int tokpushback;         /* last token pushed back */
  95 static char *wordtext;          /* text of last word returned by readtoken */
  96 MKINIT int checkkwd;            /* 1 == check for kwds, 2 == also eat newlines */
  97 static struct nodelist *backquotelist;
  98 static union node *redirnode;
  99 static struct heredoc *heredoc;
 100 static int quoteflag;           /* set if (part of) last token was quoted */
 101 static int startlinno;          /* line # where last token started */
 102 static int funclinno;           /* line # where the current function started */
 103 static struct parser_temp *parser_temp;
 104
 105
 106 static union node *list(int, int);
 107 static union node *andor(void);
 108 static union node *pipeline(void);
 109 static union node *command(void);
 110 static union node *simplecmd(union node **, union node *);
 111 static union node *makename(void);
 112 static void parsefname(void);
 113 static void parseheredoc(void);
 114 static int peektoken(void);
 115 static int readtoken(void);
 116 static int xxreadtoken(void);
 117 static int readtoken1(int, char const *, char *, int);
 118 static int noexpand(char *);
 119 static void synexpect(int) __dead2;
 120 static void synerror(const char *) __dead2;
 121 static void setprompt(int);
 122
 123
 124 static void *
 125 parser_temp_alloc(size_t len)
 126 {
 127         struct parser_temp *t;
 128
 129         INTOFF;
 130         t = ckmalloc(sizeof(*t));
 131         t->data = NULL;
 132         t->next = parser_temp;
 133         parser_temp = t;
 134         t->data = ckmalloc(len);
 135         INTON;
 136         return t->data;
 137 }
 138
 139
 140 static void *
 141 parser_temp_realloc(void *ptr, size_t len)
 142 {
 143         struct parser_temp *t;
 144
 145         INTOFF;
 146         t = parser_temp;
 147         if (ptr != t->data)
 148                 error("bug: parser_temp_realloc misused");
 149         t->data = ckrealloc(t->data, len);
 150         INTON;
 151         return t->data;
 152 }
 153
 154
 155 static void
 156 parser_temp_free_upto(void *ptr)
 157 {
 158         struct parser_temp *t;
 159         int done = 0;
 160
 161         INTOFF;
 162         while (parser_temp != NULL && !done) {
 163                 t = parser_temp;
 164                 parser_temp = t->next;
 165                 done = t->data == ptr;
 166                 ckfree(t->data);
 167                 ckfree(t);
 168         }
 169         INTON;
 170         if (!done)
 171                 error("bug: parser_temp_free_upto misused");
 172 }
 173
 174
 175 static void
 176 parser_temp_free_all(void)
 177 {
 178         struct parser_temp *t;
 179
 180         INTOFF;
 181         while (parser_temp != NULL) {
 182                 t = parser_temp;
 183                 parser_temp = t->next;
 184                 ckfree(t->data);
 185                 ckfree(t);
 186         }
 187         INTON;
 188 }
 189
 190
 191 /*
 192  * Read and parse a command.  Returns NEOF on end of file.  (NULL is a
 193  * valid parse tree indicating a blank line.)
 194  */
 195
 196 union node *
 197 parsecmd(int interact)
 198 {
 199         int t;
 200
 201         /* This assumes the parser is not re-entered,
 202          * which could happen if we add command substitution on PS1/PS2.
 203          */
 204         parser_temp_free_all();
 205         heredoclist = NULL;
 206
 207         tokpushback = 0;
 208         doprompt = interact;
 209         if (doprompt)
 210                 setprompt(1);
 211         else
 212                 setprompt(0);
 213         needprompt = 0;
 214         t = readtoken();
 215         if (t == TEOF)
 216                 return NEOF;
 217         if (t == TNL)
 218                 return NULL;
 219         tokpushback++;
 220         return list(1, 1);
 221 }
 222
 223
 224 static union node *
 225 list(int nlflag, int erflag)
 226 {
 227         union node *ntop, *n1, *n2, *n3;
 228         int tok;
 229
 230         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 231         if (!nlflag && !erflag && tokendlist[peektoken()])
 232                 return NULL;
 233         ntop = n1 = NULL;
 234         for (;;) {
 235                 n2 = andor();
 236                 tok = readtoken();
 237                 if (tok == TBACKGND) {
 238                         if (n2 != NULL && n2->type == NPIPE) {
 239                                 n2->npipe.backgnd = 1;
 240                         } else if (n2 != NULL && n2->type == NREDIR) {
 241                                 n2->type = NBACKGND;
 242                         } else {
 243                                 n3 = (union node *)stalloc(sizeof (struct nredir));
 244                                 n3->type = NBACKGND;
 245                                 n3->nredir.n = n2;
 246                                 n3->nredir.redirect = NULL;
 247                                 n2 = n3;
 248                         }
 249                 }
 250                 if (ntop == NULL)
 251                         ntop = n2;
 252                 else if (n1 == NULL) {
 253                         n1 = (union node *)stalloc(sizeof (struct nbinary));
 254                         n1->type = NSEMI;
 255                         n1->nbinary.ch1 = ntop;
 256                         n1->nbinary.ch2 = n2;
 257                         ntop = n1;
 258                 }
 259                 else {
 260                         n3 = (union node *)stalloc(sizeof (struct nbinary));
 261                         n3->type = NSEMI;
 262                         n3->nbinary.ch1 = n1->nbinary.ch2;
 263                         n3->nbinary.ch2 = n2;
 264                         n1->nbinary.ch2 = n3;
 265                         n1 = n3;
 266                 }
 267                 switch (tok) {
 268                 case TBACKGND:
 269                 case TSEMI:
 270                         tok = readtoken();
 271                         /* FALLTHROUGH */
 272                 case TNL:
 273                         if (tok == TNL) {
 274                                 parseheredoc();
 275                                 if (nlflag)
 276                                         return ntop;
 277                         } else if (tok == TEOF && nlflag) {
 278                                 parseheredoc();
 279                                 return ntop;
 280                         } else {
 281                                 tokpushback++;
 282                         }
 283                         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 284                         if (!nlflag && (erflag ? peektoken() == TEOF :
 285                             tokendlist[peektoken()]))
 286                                 return ntop;
 287                         break;
 288                 case TEOF:
 289                         if (heredoclist)
 290                                 parseheredoc();
 291                         else
 292                                 pungetc();              /* push back EOF on input */
 293                         return ntop;
 294                 default:
 295                         if (nlflag || erflag)
 296                                 synexpect(-1);
 297                         tokpushback++;
 298                         return ntop;
 299                 }
 300         }
 301 }
 302
 303
 304
 305 static union node *
 306 andor(void)
 307 {
 308         union node *n1, *n2, *n3;
 309         int t;
 310
 311         n1 = pipeline();
 312         for (;;) {
 313                 if ((t = readtoken()) == TAND) {
 314                         t = NAND;
 315                 } else if (t == TOR) {
 316                         t = NOR;
 317                 } else {
 318                         tokpushback++;
 319                         return n1;
 320                 }
 321                 n2 = pipeline();
 322                 n3 = (union node *)stalloc(sizeof (struct nbinary));
 323                 n3->type = t;
 324                 n3->nbinary.ch1 = n1;
 325                 n3->nbinary.ch2 = n2;
 326                 n1 = n3;
 327         }
 328 }
 329
 330
 331
 332 static union node *
 333 pipeline(void)
 334 {
 335         union node *n1, *n2, *pipenode;
 336         struct nodelist *lp, *prev;
 337         int negate, t;
 338
 339         negate = 0;
 340         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 341         TRACE(("pipeline: entered\n"));
 342         while (readtoken() == TNOT)
 343                 negate = !negate;
 344         tokpushback++;
 345         n1 = command();
 346         if (readtoken() == TPIPE) {
 347                 pipenode = (union node *)stalloc(sizeof (struct npipe));
 348                 pipenode->type = NPIPE;
 349                 pipenode->npipe.backgnd = 0;
 350                 lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 351                 pipenode->npipe.cmdlist = lp;
 352                 lp->n = n1;
 353                 do {
 354                         prev = lp;
 355                         lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 356                         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 357                         t = readtoken();
 358                         tokpushback++;
 359                         if (t == TNOT)
 360                                 lp->n = pipeline();
 361                         else
 362                                 lp->n = command();
 363                         prev->next = lp;
 364                 } while (readtoken() == TPIPE);
 365                 lp->next = NULL;
 366                 n1 = pipenode;
 367         }
 368         tokpushback++;
 369         if (negate) {
 370                 n2 = (union node *)stalloc(sizeof (struct nnot));
 371                 n2->type = NNOT;
 372                 n2->nnot.com = n1;
 373                 return n2;
 374         } else
 375                 return n1;
 376 }
 377
 378
 379
 380 static union node *
 381 command(void)
 382 {
 383         union node *n1, *n2;
 384         union node *ap, **app;
 385         union node *cp, **cpp;
 386         union node *redir, **rpp;
 387         int t;
 388         int is_subshell;
 389
 390         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 391         is_subshell = 0;
 392         redir = NULL;
 393         n1 = NULL;
 394         rpp = &redir;
 395
 396         /* Check for redirection which may precede command */
 397         while (readtoken() == TREDIR) {
 398                 *rpp = n2 = redirnode;
 399                 rpp = &n2->nfile.next;
 400                 parsefname();
 401         }
 402         tokpushback++;
 403
 404         switch (readtoken()) {
 405         case TIF:
 406                 n1 = (union node *)stalloc(sizeof (struct nif));
 407                 n1->type = NIF;
 408                 if ((n1->nif.test = list(0, 0)) == NULL)
 409                         synexpect(-1);
 410                 if (readtoken() != TTHEN)
 411                         synexpect(TTHEN);
 412                 n1->nif.ifpart = list(0, 0);
 413                 n2 = n1;
 414                 while (readtoken() == TELIF) {
 415                         n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
 416                         n2 = n2->nif.elsepart;
 417                         n2->type = NIF;
 418                         if ((n2->nif.test = list(0, 0)) == NULL)
 419                                 synexpect(-1);
 420                         if (readtoken() != TTHEN)
 421                                 synexpect(TTHEN);
 422                         n2->nif.ifpart = list(0, 0);
 423                 }
 424                 if (lasttoken == TELSE)
 425                         n2->nif.elsepart = list(0, 0);
 426                 else {
 427                         n2->nif.elsepart = NULL;
 428                         tokpushback++;
 429                 }
 430                 if (readtoken() != TFI)
 431                         synexpect(TFI);
 432                 checkkwd = CHKKWD | CHKALIAS;
 433                 break;
 434         case TWHILE:
 435         case TUNTIL: {
 436                 int got;
 437                 n1 = (union node *)stalloc(sizeof (struct nbinary));
 438                 n1->type = (lasttoken == TWHILE)? NWHILE : NUNTIL;
 439                 if ((n1->nbinary.ch1 = list(0, 0)) == NULL)
 440                         synexpect(-1);
 441                 if ((got=readtoken()) != TDO) {
 442 TRACE(("expecting DO got %s %s\n", tokname[got], got == TWORD ? wordtext : ""));
 443                         synexpect(TDO);
 444                 }
 445                 n1->nbinary.ch2 = list(0, 0);
 446                 if (readtoken() != TDONE)
 447                         synexpect(TDONE);
 448                 checkkwd = CHKKWD | CHKALIAS;
 449                 break;
 450         }
 451         case TFOR:
 452                 if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
 453                         synerror("Bad for loop variable");
 454                 n1 = (union node *)stalloc(sizeof (struct nfor));
 455                 n1->type = NFOR;
 456                 n1->nfor.var = wordtext;
 457                 while (readtoken() == TNL)
 458                         ;
 459                 if (lasttoken == TWORD && ! quoteflag && equal(wordtext, "in")) {
 460                         app = &ap;
 461                         while (readtoken() == TWORD) {
 462                                 n2 = (union node *)stalloc(sizeof (struct narg));
 463                                 n2->type = NARG;
 464                                 n2->narg.text = wordtext;
 465                                 n2->narg.backquote = backquotelist;
 466                                 *app = n2;
 467                                 app = &n2->narg.next;
 468                         }
 469                         *app = NULL;
 470                         n1->nfor.args = ap;
 471                         if (lasttoken != TNL && lasttoken != TSEMI)
 472                                 synexpect(-1);
 473                 } else {
 474                         static char argvars[5] = {
 475                                 CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'
 476                         };
 477                         n2 = (union node *)stalloc(sizeof (struct narg));
 478                         n2->type = NARG;
 479                         n2->narg.text = argvars;
 480                         n2->narg.backquote = NULL;
 481                         n2->narg.next = NULL;
 482                         n1->nfor.args = n2;
 483                         /*
 484                          * Newline or semicolon here is optional (but note
 485                          * that the original Bourne shell only allowed NL).
 486                          */
 487                         if (lasttoken != TNL && lasttoken != TSEMI)
 488                                 tokpushback++;
 489                 }
 490                 checkkwd = CHKNL | CHKKWD | CHKALIAS;
 491                 if ((t = readtoken()) == TDO)
 492                         t = TDONE;
 493                 else if (t == TBEGIN)
 494                         t = TEND;
 495                 else
 496                         synexpect(-1);
 497                 n1->nfor.body = list(0, 0);
 498                 if (readtoken() != t)
 499                         synexpect(t);
 500                 checkkwd = CHKKWD | CHKALIAS;
 501                 break;
 502         case TCASE:
 503                 n1 = (union node *)stalloc(sizeof (struct ncase));
 504                 n1->type = NCASE;
 505                 if (readtoken() != TWORD)
 506                         synexpect(TWORD);
 507                 n1->ncase.expr = n2 = (union node *)stalloc(sizeof (struct narg));
 508                 n2->type = NARG;
 509                 n2->narg.text = wordtext;
 510                 n2->narg.backquote = backquotelist;
 511                 n2->narg.next = NULL;
 512                 while (readtoken() == TNL);
 513                 if (lasttoken != TWORD || ! equal(wordtext, "in"))
 514                         synerror("expecting \"in\"");
 515                 cpp = &n1->ncase.cases;
 516                 checkkwd = CHKNL | CHKKWD, readtoken();
 517                 while (lasttoken != TESAC) {
 518                         *cpp = cp = (union node *)stalloc(sizeof (struct nclist));
 519                         cp->type = NCLIST;
 520                         app = &cp->nclist.pattern;
 521                         if (lasttoken == TLP)
 522                                 readtoken();
 523                         for (;;) {
 524                                 *app = ap = (union node *)stalloc(sizeof (struct narg));
 525                                 ap->type = NARG;
 526                                 ap->narg.text = wordtext;
 527                                 ap->narg.backquote = backquotelist;
 528                                 checkkwd = CHKNL | CHKKWD;
 529                                 if (readtoken() != TPIPE)
 530                                         break;
 531                                 app = &ap->narg.next;
 532                                 readtoken();
 533                         }
 534                         ap->narg.next = NULL;
 535                         if (lasttoken != TRP)
 536                                 synexpect(TRP);
 537                         cp->nclist.body = list(0, 0);
 538
 539                         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 540                         if ((t = readtoken()) != TESAC) {
 541                                 if (t == TENDCASE)
 542                                         ;
 543                                 else if (t == TFALLTHRU)
 544                                         cp->type = NCLISTFALLTHRU;
 545                                 else
 546                                         synexpect(TENDCASE);
 547                                 checkkwd = CHKNL | CHKKWD, readtoken();
 548                         }
 549                         cpp = &cp->nclist.next;
 550                 }
 551                 *cpp = NULL;
 552                 checkkwd = CHKKWD | CHKALIAS;
 553                 break;
 554         case TLP:
 555                 n1 = (union node *)stalloc(sizeof (struct nredir));
 556                 n1->type = NSUBSHELL;
 557                 n1->nredir.n = list(0, 0);
 558                 n1->nredir.redirect = NULL;
 559                 if (readtoken() != TRP)
 560                         synexpect(TRP);
 561                 checkkwd = CHKKWD | CHKALIAS;
 562                 is_subshell = 1;
 563                 break;
 564         case TBEGIN:
 565                 n1 = list(0, 0);
 566                 if (readtoken() != TEND)
 567                         synexpect(TEND);
 568                 checkkwd = CHKKWD | CHKALIAS;
 569                 break;
 570         /* Handle an empty command like other simple commands.  */
 571         case TBACKGND:
 572         case TSEMI:
 573         case TAND:
 574         case TOR:
 575                 /*
 576                  * An empty command before a ; doesn't make much sense, and
 577                  * should certainly be disallowed in the case of `if ;'.
 578                  */
 579                 if (!redir)
 580                         synexpect(-1);
 581         case TNL:
 582         case TEOF:
 583         case TWORD:
 584         case TRP:
 585                 tokpushback++;
 586                 n1 = simplecmd(rpp, redir);
 587                 return n1;
 588         default:
 589                 synexpect(-1);
 590         }
 591
 592         /* Now check for redirection which may follow command */
 593         while (readtoken() == TREDIR) {
 594                 *rpp = n2 = redirnode;
 595                 rpp = &n2->nfile.next;
 596                 parsefname();
 597         }
 598         tokpushback++;
 599         *rpp = NULL;
 600         if (redir) {
 601                 if (!is_subshell) {
 602                         n2 = (union node *)stalloc(sizeof (struct nredir));
 603                         n2->type = NREDIR;
 604                         n2->nredir.n = n1;
 605                         n1 = n2;
 606                 }
 607                 n1->nredir.redirect = redir;
 608         }
 609
 610         return n1;
 611 }
 612
 613
 614 static union node *
 615 simplecmd(union node **rpp, union node *redir)
 616 {
 617         union node *args, **app;
 618         union node **orig_rpp = rpp;
 619         union node *n = NULL;
 620         int special;
 621         int savecheckkwd;
 622
 623         /* If we don't have any redirections already, then we must reset */
 624         /* rpp to be the address of the local redir variable.  */
 625         if (redir == NULL)
 626                 rpp = &redir;
 627
 628         args = NULL;
 629         app = &args;
 630         /*
 631          * We save the incoming value, because we need this for shell
 632          * functions.  There can not be a redirect or an argument between
 633          * the function name and the open parenthesis.
 634          */
 635         orig_rpp = rpp;
 636
 637         savecheckkwd = CHKALIAS;
 638
 639         for (;;) {
 640                 checkkwd = savecheckkwd;
 641                 if (readtoken() == TWORD) {
 642                         n = (union node *)stalloc(sizeof (struct narg));
 643                         n->type = NARG;
 644                         n->narg.text = wordtext;
 645                         n->narg.backquote = backquotelist;
 646                         *app = n;
 647                         app = &n->narg.next;
 648                         if (savecheckkwd != 0 && !isassignment(wordtext))
 649                                 savecheckkwd = 0;
 650                 } else if (lasttoken == TREDIR) {
 651                         *rpp = n = redirnode;
 652                         rpp = &n->nfile.next;
 653                         parsefname();   /* read name of redirection file */
 654                 } else if (lasttoken == TLP && app == &args->narg.next
 655                                             && rpp == orig_rpp) {
 656                         /* We have a function */
 657                         if (readtoken() != TRP)
 658                                 synexpect(TRP);
 659                         funclinno = plinno;
 660                         /*
 661                          * - Require plain text.
 662                          * - Functions with '/' cannot be called.
 663                          * - Reject name=().
 664                          * - Reject ksh extended glob patterns.
 665                          */
 666                         if (!noexpand(n->narg.text) || quoteflag ||
 667                             strchr(n->narg.text, '/') ||
 668                             strchr("!%*+-=?@}~",
 669                                 n->narg.text[strlen(n->narg.text) - 1]))
 670                                 synerror("Bad function name");
 671                         rmescapes(n->narg.text);
 672                         if (find_builtin(n->narg.text, &special) >= 0 &&
 673                             special)
 674                                 synerror("Cannot override a special builtin with a function");
 675                         n->type = NDEFUN;
 676                         n->narg.next = command();
 677                         funclinno = 0;
 678                         return n;
 679                 } else {
 680                         tokpushback++;
 681                         break;
 682                 }
 683         }
 684         *app = NULL;
 685         *rpp = NULL;
 686         n = (union node *)stalloc(sizeof (struct ncmd));
 687         n->type = NCMD;
 688         n->ncmd.args = args;
 689         n->ncmd.redirect = redir;
 690         return n;
 691 }
 692
 693 static union node *
 694 makename(void)
 695 {
 696         union node *n;
 697
 698         n = (union node *)stalloc(sizeof (struct narg));
 699         n->type = NARG;
 700         n->narg.next = NULL;
 701         n->narg.text = wordtext;
 702         n->narg.backquote = backquotelist;
 703         return n;
 704 }
 705
 706 void
 707 fixredir(union node *n, const char *text, int err)
 708 {
 709         TRACE(("Fix redir %s %d\n", text, err));
 710         if (!err)
 711                 n->ndup.vname = NULL;
 712
 713         if (is_digit(text[0]) && text[1] == '\0')
 714                 n->ndup.dupfd = digit_val(text[0]);
 715         else if (text[0] == '-' && text[1] == '\0')
 716                 n->ndup.dupfd = -1;
 717         else {
 718
 719                 if (err)
 720                         synerror("Bad fd number");
 721                 else
 722                         n->ndup.vname = makename();
 723         }
 724 }
 725
 726
 727 static void
 728 parsefname(void)
 729 {
 730         union node *n = redirnode;
 731
 732         if (readtoken() != TWORD)
 733                 synexpect(-1);
 734         if (n->type == NHERE) {
 735                 struct heredoc *here = heredoc;
 736                 struct heredoc *p;
 737                 int i;
 738
 739                 if (quoteflag == 0)
 740                         n->type = NXHERE;
 741                 TRACE(("Here document %d\n", n->type));
 742                 if (here->striptabs) {
 743                         while (*wordtext == '\t')
 744                                 wordtext++;
 745                 }
 746                 if (! noexpand(wordtext) || (i = strlen(wordtext)) == 0 || i > EOFMARKLEN)
 747                         synerror("Illegal eof marker for << redirection");
 748                 rmescapes(wordtext);
 749                 here->eofmark = wordtext;
 750                 here->next = NULL;
 751                 if (heredoclist == NULL)
 752                         heredoclist = here;
 753                 else {
 754                         for (p = heredoclist ; p->next ; p = p->next);
 755                         p->next = here;
 756                 }
 757         } else if (n->type == NTOFD || n->type == NFROMFD) {
 758                 fixredir(n, wordtext, 0);
 759         } else {
 760                 n->nfile.fname = makename();
 761         }
 762 }
 763
 764
 765 /*
 766  * Input any here documents.
 767  */
 768
 769 static void
 770 parseheredoc(void)
 771 {
 772         struct heredoc *here;
 773         union node *n;
 774
 775         while (heredoclist) {
 776                 here = heredoclist;
 777                 heredoclist = here->next;
 778                 if (needprompt) {
 779                         setprompt(2);
 780                         needprompt = 0;
 781                 }
 782                 readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
 783                                 here->eofmark, here->striptabs);
 784                 n = (union node *)stalloc(sizeof (struct narg));
 785                 n->narg.type = NARG;
 786                 n->narg.next = NULL;
 787                 n->narg.text = wordtext;
 788                 n->narg.backquote = backquotelist;
 789                 here->here->nhere.doc = n;
 790         }
 791 }
 792
 793 static int
 794 peektoken(void)
 795 {
 796         int t;
 797
 798         t = readtoken();
 799         tokpushback++;
 800         return (t);
 801 }
 802
 803 static int
 804 readtoken(void)
 805 {
 806         int t;
 807         struct alias *ap;
 808 #ifdef DEBUG
 809         int alreadyseen = tokpushback;
 810 #endif
 811
 812         top:
 813         t = xxreadtoken();
 814
 815         /*
 816          * eat newlines
 817          */
 818         if (checkkwd & CHKNL) {
 819                 while (t == TNL) {
 820                         parseheredoc();
 821                         t = xxreadtoken();
 822                 }
 823         }
 824
 825         /*
 826          * check for keywords and aliases
 827          */
 828         if (t == TWORD && !quoteflag)
 829         {
 830                 const char * const *pp;
 831
 832                 if (checkkwd & CHKKWD)
 833                         for (pp = parsekwd; *pp; pp++) {
 834                                 if (**pp == *wordtext && equal(*pp, wordtext))
 835                                 {
 836                                         lasttoken = t = pp - parsekwd + KWDOFFSET;
 837                                         TRACE(("keyword %s recognized\n", tokname[t]));
 838                                         goto out;
 839                                 }
 840                         }
 841                 if (checkkwd & CHKALIAS &&
 842                     (ap = lookupalias(wordtext, 1)) != NULL) {
 843                         pushstring(ap->val, strlen(ap->val), ap);
 844                         goto top;
 845                 }
 846         }
 847 out:
 848         if (t != TNOT)
 849                 checkkwd = 0;
 850
 851 #ifdef DEBUG
 852         if (!alreadyseen)
 853             TRACE(("token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 854         else
 855             TRACE(("reread token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 856 #endif
 857         return (t);
 858 }
 859
 860
 861 /*
 862  * Read the next input token.
 863  * If the token is a word, we set backquotelist to the list of cmds in
 864  *      backquotes.  We set quoteflag to true if any part of the word was
 865  *      quoted.
 866  * If the token is TREDIR, then we set redirnode to a structure containing
 867  *      the redirection.
 868  * In all cases, the variable startlinno is set to the number of the line
 869  *      on which the token starts.
 870  *
 871  * [Change comment:  here documents and internal procedures]
 872  * [Readtoken shouldn't have any arguments.  Perhaps we should make the
 873  *  word parsing code into a separate routine.  In this case, readtoken
 874  *  doesn't need to have any internal procedures, but parseword does.
 875  *  We could also make parseoperator in essence the main routine, and
 876  *  have parseword (readtoken1?) handle both words and redirection.]
 877  */
 878
 879 #define RETURN(token)   return lasttoken = token
 880
 881 static int
 882 xxreadtoken(void)
 883 {
 884         int c;
 885
 886         if (tokpushback) {
 887                 tokpushback = 0;
 888                 return lasttoken;
 889         }
 890         if (needprompt) {
 891                 setprompt(2);
 892                 needprompt = 0;
 893         }
 894         startlinno = plinno;
 895         for (;;) {      /* until token or start of word found */
 896                 c = pgetc_macro();
 897                 switch (c) {
 898                 case ' ': case '\t':
 899                         continue;
 900                 case '#':
 901                         while ((c = pgetc()) != '\n' && c != PEOF);
 902                         pungetc();
 903                         continue;
 904                 case '\\':
 905                         if (pgetc() == '\n') {
 906                                 startlinno = ++plinno;
 907                                 if (doprompt)
 908                                         setprompt(2);
 909                                 else
 910                                         setprompt(0);
 911                                 continue;
 912                         }
 913                         pungetc();
 914                         goto breakloop;
 915                 case '\n':
 916                         plinno++;
 917                         needprompt = doprompt;
 918                         RETURN(TNL);
 919                 case PEOF:
 920                         RETURN(TEOF);
 921                 case '&':
 922                         if (pgetc() == '&')
 923                                 RETURN(TAND);
 924                         pungetc();
 925                         RETURN(TBACKGND);
 926                 case '|':
 927                         if (pgetc() == '|')
 928                                 RETURN(TOR);
 929                         pungetc();
 930                         RETURN(TPIPE);
 931                 case ';':
 932                         c = pgetc();
 933                         if (c == ';')
 934                                 RETURN(TENDCASE);
 935                         else if (c == '&')
 936                                 RETURN(TFALLTHRU);
 937                         pungetc();
 938                         RETURN(TSEMI);
 939                 case '(':
 940                         RETURN(TLP);
 941                 case ')':
 942                         RETURN(TRP);
 943                 default:
 944                         goto breakloop;
 945                 }
 946         }
 947 breakloop:
 948         return readtoken1(c, BASESYNTAX, NULL, 0);
 949 #undef RETURN
 950 }
 951
 952
 953 #define MAXNEST_STATIC 8
 954 struct tokenstate
 955 {
 956         const char *syntax; /* *SYNTAX */
 957         int parenlevel; /* levels of parentheses in arithmetic */
 958         enum tokenstate_category
 959         {
 960                 TSTATE_TOP,
 961                 TSTATE_VAR_OLD, /* ${var+-=?}, inherits dquotes */
 962                 TSTATE_VAR_NEW, /* other ${var...}, own dquote state */
 963                 TSTATE_ARITH
 964         } category;
 965 };
 966
 967
 968 /*
 969  * Called to parse command substitutions.
 970  */
 971
 972 static char *
 973 parsebackq(char *out, struct nodelist **pbqlist,
 974     int oldstyle, int dblquote, int quoted)
 975 {
 976         struct nodelist **nlpp;
 977         union node *n;
 978         char *volatile str;
 979         struct jmploc jmploc;
 980         struct jmploc *const savehandler = handler;
 981         int savelen;
 982         int saveprompt;
 983         const int bq_startlinno = plinno;
 984         char *volatile ostr = NULL;
 985         struct parsefile *const savetopfile = getcurrentfile();
 986         struct heredoc *const saveheredoclist = heredoclist;
 987         struct heredoc *here;
 988
 989         str = NULL;
 990         if (setjmp(jmploc.loc)) {
 991                 popfilesupto(savetopfile);
 992                 if (str)
 993                         ckfree(str);
 994                 if (ostr)
 995                         ckfree(ostr);
 996                 heredoclist = saveheredoclist;
 997                 handler = savehandler;
 998                 if (exception == EXERROR) {
 999                         startlinno = bq_startlinno;
1000                         synerror("Error in command substitution");
1001                 }
1002                 longjmp(handler->loc, 1);
1003         }
1004         INTOFF;
1005         savelen = out - stackblock();
1006         if (savelen > 0) {
1007                 str = ckmalloc(savelen);
1008                 memcpy(str, stackblock(), savelen);
1009         }
1010         handler = &jmploc;
1011         heredoclist = NULL;
1012         INTON;
1013         if (oldstyle) {
1014                 /*
1015                  * We must read until the closing backquote, giving special
1016                  * treatment to some slashes, and then push the string and
1017                  * reread it as input, interpreting it normally.
1018                  */
1019                 char *oout;
1020                 int c, olen;
1021
1022                 STARTSTACKSTR(oout);
1023                 for (;;) {
1024                         if (needprompt) {
1025                                 setprompt(2);
1026                                 needprompt = 0;
1027                         }
1028                         CHECKSTRSPACE(2, oout);
1029                         switch (c = pgetc()) {
1030                         case '`':
1031                                 goto done;
1032
1033                         case '\\':
1034                                 if ((c = pgetc()) == '\n') {
1035                                         plinno++;
1036                                         if (doprompt)
1037                                                 setprompt(2);
1038                                         else
1039                                                 setprompt(0);
1040                                         /*
1041                                          * If eating a newline, avoid putting
1042                                          * the newline into the new character
1043                                          * stream (via the USTPUTC after the
1044                                          * switch).
1045                                          */
1046                                         continue;
1047                                 }
1048                                 if (c != '\\' && c != '`' && c != '$'
1049                                     && (!dblquote || c != '"'))
1050                                         USTPUTC('\\', oout);
1051                                 break;
1052
1053                         case '\n':
1054                                 plinno++;
1055                                 needprompt = doprompt;
1056                                 break;
1057
1058                         case PEOF:
1059                                 startlinno = plinno;
1060                                 synerror("EOF in backquote substitution");
1061                                 break;
1062
1063                         default:
1064                                 break;
1065                         }
1066                         USTPUTC(c, oout);
1067                 }
1068 done:
1069                 USTPUTC('\0', oout);
1070                 olen = oout - stackblock();
1071                 INTOFF;
1072                 ostr = ckmalloc(olen);
1073                 memcpy(ostr, stackblock(), olen);
1074                 setinputstring(ostr, 1);
1075                 INTON;
1076         }
1077         nlpp = pbqlist;
1078         while (*nlpp)
1079                 nlpp = &(*nlpp)->next;
1080         *nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
1081         (*nlpp)->next = NULL;
1082
1083         if (oldstyle) {
1084                 saveprompt = doprompt;
1085                 doprompt = 0;
1086         }
1087
1088         n = list(0, oldstyle);
1089
1090         if (oldstyle)
1091                 doprompt = saveprompt;
1092         else {
1093                 if (readtoken() != TRP)
1094                         synexpect(TRP);
1095         }
1096
1097         (*nlpp)->n = n;
1098         if (oldstyle) {
1099                 /*
1100                  * Start reading from old file again, ignoring any pushed back
1101                  * tokens left from the backquote parsing
1102                  */
1103                 popfile();
1104                 tokpushback = 0;
1105         }
1106         STARTSTACKSTR(out);
1107         CHECKSTRSPACE(savelen + 1, out);
1108         INTOFF;
1109         if (str) {
1110                 memcpy(out, str, savelen);
1111                 STADJUST(savelen, out);
1112                 ckfree(str);
1113                 str = NULL;
1114         }
1115         if (ostr) {
1116                 ckfree(ostr);
1117                 ostr = NULL;
1118         }
1119         here = saveheredoclist;
1120         if (here != NULL) {
1121                 while (here->next != NULL)
1122                         here = here->next;
1123                 here->next = heredoclist;
1124                 heredoclist = saveheredoclist;
1125         }
1126         handler = savehandler;
1127         INTON;
1128         if (quoted)
1129                 USTPUTC(CTLBACKQ | CTLQUOTE, out);
1130         else
1131                 USTPUTC(CTLBACKQ, out);
1132         return out;
1133 }
1134
1135
1136 /*
1137  * Called to parse a backslash escape sequence inside $'...'.
1138  * The backslash has already been read.
1139  */
1140 static char *
1141 readcstyleesc(char *out)
1142 {
1143         int c, v, i, n;
1144
1145         c = pgetc();
1146         switch (c) {
1147         case '\0':
1148                 synerror("Unterminated quoted string");
1149         case '\n':
1150                 plinno++;
1151                 if (doprompt)
1152                         setprompt(2);
1153                 else
1154                         setprompt(0);
1155                 return out;
1156         case '\\':
1157         case '\'':
1158         case '"':
1159                 v = c;
1160                 break;
1161         case 'a': v = '\a'; break;
1162         case 'b': v = '\b'; break;
1163         case 'e': v = '\033'; break;
1164         case 'f': v = '\f'; break;
1165         case 'n': v = '\n'; break;
1166         case 'r': v = '\r'; break;
1167         case 't': v = '\t'; break;
1168         case 'v': v = '\v'; break;
1169         case 'x':
1170                   v = 0;
1171                   for (;;) {
1172                           c = pgetc();
1173                           if (c >= '0' && c <= '9')
1174                                   v = (v << 4) + c - '0';
1175                           else if (c >= 'A' && c <= 'F')
1176                                   v = (v << 4) + c - 'A' + 10;
1177                           else if (c >= 'a' && c <= 'f')
1178                                   v = (v << 4) + c - 'a' + 10;
1179                           else
1180                                   break;
1181                   }
1182                   pungetc();
1183                   break;
1184         case '0': case '1': case '2': case '3':
1185         case '4': case '5': case '6': case '7':
1186                   v = c - '0';
1187                   c = pgetc();
1188                   if (c >= '0' && c <= '7') {
1189                           v <<= 3;
1190                           v += c - '0';
1191                           c = pgetc();
1192                           if (c >= '0' && c <= '7') {
1193                                   v <<= 3;
1194                                   v += c - '0';
1195                           } else
1196                                   pungetc();
1197                   } else
1198                           pungetc();
1199                   break;
1200         case 'c':
1201                   c = pgetc();
1202                   if (c < 0x3f || c > 0x7a || c == 0x60)
1203                           synerror("Bad escape sequence");
1204                   if (c == '\\' && pgetc() != '\\')
1205                           synerror("Bad escape sequence");
1206                   if (c == '?')
1207                           v = 127;
1208                   else
1209                           v = c & 0x1f;
1210                   break;
1211         case 'u':
1212         case 'U':
1213                   n = c == 'U' ? 8 : 4;
1214                   v = 0;
1215                   for (i = 0; i < n; i++) {
1216                           c = pgetc();
1217                           if (c >= '0' && c <= '9')
1218                                   v = (v << 4) + c - '0';
1219                           else if (c >= 'A' && c <= 'F')
1220                                   v = (v << 4) + c - 'A' + 10;
1221                           else if (c >= 'a' && c <= 'f')
1222                                   v = (v << 4) + c - 'a' + 10;
1223                           else
1224                                   synerror("Bad escape sequence");
1225                   }
1226                   if (v == 0 || (v >= 0xd800 && v <= 0xdfff))
1227                           synerror("Bad escape sequence");
1228                   /* We really need iconv here. */
1229                   if (initial_localeisutf8 && v > 127) {
1230                           CHECKSTRSPACE(4, out);
1231                           /*
1232                            * We cannot use wctomb() as the locale may have
1233                            * changed.
1234                            */
1235                           if (v <= 0x7ff) {
1236                                   USTPUTC(0xc0 | v >> 6, out);
1237                                   USTPUTC(0x80 | (v & 0x3f), out);
1238                                   return out;
1239                           } else if (v <= 0xffff) {
1240                                   USTPUTC(0xe0 | v >> 12, out);
1241                                   USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
1242                                   USTPUTC(0x80 | (v & 0x3f), out);
1243                                   return out;
1244                           } else if (v <= 0x10ffff) {
1245                                   USTPUTC(0xf0 | v >> 18, out);
1246                                   USTPUTC(0x80 | ((v >> 12) & 0x3f), out);
1247                                   USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
1248                                   USTPUTC(0x80 | (v & 0x3f), out);
1249                                   return out;
1250                           }
1251                   }
1252                   if (v > 127)
1253                           v = '?';
1254                   break;
1255         default:
1256                   synerror("Bad escape sequence");
1257         }
1258         v = (char)v;
1259         /*
1260          * We can't handle NUL bytes.
1261          * POSIX says we should skip till the closing quote.
1262          */
1263         if (v == '\0') {
1264                 while ((c = pgetc()) != '\'') {
1265                         if (c == '\\')
1266                                 c = pgetc();
1267                         if (c == PEOF)
1268                                 synerror("Unterminated quoted string");
1269                 }
1270                 pungetc();
1271                 return out;
1272         }
1273         if (SQSYNTAX[v] == CCTL)
1274                 USTPUTC(CTLESC, out);
1275         USTPUTC(v, out);
1276         return out;
1277 }
1278
1279
1280 /*
1281  * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
1282  * is not NULL, read a here document.  In the latter case, eofmark is the
1283  * word which marks the end of the document and striptabs is true if
1284  * leading tabs should be stripped from the document.  The argument firstc
1285  * is the first character of the input token or document.
1286  *
1287  * Because C does not have internal subroutines, I have simulated them
1288  * using goto's to implement the subroutine linkage.  The following macros
1289  * will run code that appears at the end of readtoken1.
1290  */
1291
1292 #define CHECKEND()      {goto checkend; checkend_return:;}
1293 #define PARSEREDIR()    {goto parseredir; parseredir_return:;}
1294 #define PARSESUB()      {goto parsesub; parsesub_return:;}
1295 #define PARSEARITH()    {goto parsearith; parsearith_return:;}
1296
1297 static int
1298 readtoken1(int firstc, char const *initialsyntax, char *eofmark, int striptabs)
1299 {
1300         int c = firstc;
1301         char * volatile out;
1302         int len;
1303         char line[EOFMARKLEN + 1];
1304         struct nodelist *bqlist;
1305         volatile int quotef;
1306         int newvarnest;
1307         int level;
1308         int synentry;
1309         struct tokenstate state_static[MAXNEST_STATIC];
1310         int maxnest = MAXNEST_STATIC;
1311         struct tokenstate *state = state_static;
1312         int sqiscstyle = 0;
1313
1314         startlinno = plinno;
1315         quotef = 0;
1316         bqlist = NULL;
1317         newvarnest = 0;
1318         level = 0;
1319         state[level].syntax = initialsyntax;
1320         state[level].parenlevel = 0;
1321         state[level].category = TSTATE_TOP;
1322
1323         STARTSTACKSTR(out);
1324         loop: { /* for each line, until end of word */
1325                 CHECKEND();     /* set c to PEOF if at end of here document */
1326                 for (;;) {      /* until end of line or end of word */
1327                         CHECKSTRSPACE(4, out);  /* permit 4 calls to USTPUTC */
1328
1329                         synentry = state[level].syntax[c];
1330
1331                         switch(synentry) {
1332                         case CNL:       /* '\n' */
1333                                 if (state[level].syntax == BASESYNTAX)
1334                                         goto endword;   /* exit outer loop */
1335                                 USTPUTC(c, out);
1336                                 plinno++;
1337                                 if (doprompt)
1338                                         setprompt(2);
1339                                 else
1340                                         setprompt(0);
1341                                 c = pgetc();
1342                                 goto loop;              /* continue outer loop */
1343                         case CSBACK:
1344                                 if (sqiscstyle) {
1345                                         out = readcstyleesc(out);
1346                                         break;
1347                                 }
1348                                 /* FALLTHROUGH */
1349                         case CWORD:
1350                                 USTPUTC(c, out);
1351                                 break;
1352                         case CCTL:
1353                                 if (eofmark == NULL || initialsyntax != SQSYNTAX)
1354                                         USTPUTC(CTLESC, out);
1355                                 USTPUTC(c, out);
1356                                 break;
1357                         case CBACK:     /* backslash */
1358                                 c = pgetc();
1359                                 if (c == PEOF) {
1360                                         USTPUTC('\\', out);
1361                                         pungetc();
1362                                 } else if (c == '\n') {
1363                                         plinno++;
1364                                         if (doprompt)
1365                                                 setprompt(2);
1366                                         else
1367                                                 setprompt(0);
1368                                 } else {
1369                                         if (state[level].syntax == DQSYNTAX &&
1370                                             c != '\\' && c != '`' && c != '$' &&
1371                                             (c != '"' || (eofmark != NULL &&
1372                                                 newvarnest == 0)) &&
1373                                             (c != '}' || state[level].category != TSTATE_VAR_OLD))
1374                                                 USTPUTC('\\', out);
1375                                         if ((eofmark == NULL ||
1376                                             newvarnest > 0) &&
1377                                             state[level].syntax == BASESYNTAX)
1378                                                 USTPUTC(CTLQUOTEMARK, out);
1379                                         if (SQSYNTAX[c] == CCTL)
1380                                                 USTPUTC(CTLESC, out);
1381                                         USTPUTC(c, out);
1382                                         if ((eofmark == NULL ||
1383                                             newvarnest > 0) &&
1384                                             state[level].syntax == BASESYNTAX &&
1385                                             state[level].category == TSTATE_VAR_OLD)
1386                                                 USTPUTC(CTLQUOTEEND, out);
1387                                         quotef++;
1388                                 }
1389                                 break;
1390                         case CSQUOTE:
1391                                 USTPUTC(CTLQUOTEMARK, out);
1392                                 state[level].syntax = SQSYNTAX;
1393                                 sqiscstyle = 0;
1394                                 break;
1395                         case CDQUOTE:
1396                                 USTPUTC(CTLQUOTEMARK, out);
1397                                 state[level].syntax = DQSYNTAX;
1398                                 break;
1399                         case CENDQUOTE:
1400                                 if (eofmark != NULL && newvarnest == 0)
1401                                         USTPUTC(c, out);
1402                                 else {
1403                                         if (state[level].category == TSTATE_VAR_OLD)
1404                                                 USTPUTC(CTLQUOTEEND, out);
1405                                         state[level].syntax = BASESYNTAX;
1406                                         quotef++;
1407                                 }
1408                                 break;
1409                         case CVAR:      /* '$' */
1410                                 PARSESUB();             /* parse substitution */
1411                                 break;
1412                         case CENDVAR:   /* '}' */
1413                                 if (level > 0 &&
1414                                     ((state[level].category == TSTATE_VAR_OLD &&
1415                                       state[level].syntax ==
1416                                       state[level - 1].syntax) ||
1417                                     (state[level].category == TSTATE_VAR_NEW &&
1418                                      state[level].syntax == BASESYNTAX))) {
1419                                         if (state[level].category == TSTATE_VAR_NEW)
1420                                                 newvarnest--;
1421                                         level--;
1422                                         USTPUTC(CTLENDVAR, out);
1423                                 } else {
1424                                         USTPUTC(c, out);
1425                                 }
1426                                 break;
1427                         case CLP:       /* '(' in arithmetic */
1428                                 state[level].parenlevel++;
1429                                 USTPUTC(c, out);
1430                                 break;
1431                         case CRP:       /* ')' in arithmetic */
1432                                 if (state[level].parenlevel > 0) {
1433                                         USTPUTC(c, out);
1434                                         --state[level].parenlevel;
1435                                 } else {
1436                                         if (pgetc() == ')') {
1437                                                 if (level > 0 &&
1438                                                     state[level].category == TSTATE_ARITH) {
1439                                                         level--;
1440                                                         USTPUTC(CTLENDARI, out);
1441                                                 } else
1442                                                         USTPUTC(')', out);
1443                                         } else {
1444                                                 /*
1445                                                  * unbalanced parens
1446                                                  *  (don't 2nd guess - no error)
1447                                                  */
1448                                                 pungetc();
1449                                                 USTPUTC(')', out);
1450                                         }
1451                                 }
1452                                 break;
1453                         case CBQUOTE:   /* '`' */
1454                                 out = parsebackq(out, &bqlist, 1,
1455                                     state[level].syntax == DQSYNTAX &&
1456                                     (eofmark == NULL || newvarnest > 0),
1457                                     state[level].syntax == DQSYNTAX || state[level].syntax == ARISYNTAX);
1458                                 break;
1459                         case CEOF:
1460                                 goto endword;           /* exit outer loop */
1461                         case CIGN:
1462                                 break;
1463                         default:
1464                                 if (level == 0)
1465                                         goto endword;   /* exit outer loop */
1466                                 USTPUTC(c, out);
1467                         }
1468                         c = pgetc_macro();
1469                 }
1470         }
1471 endword:
1472         if (state[level].syntax == ARISYNTAX)
1473                 synerror("Missing '))'");
1474         if (state[level].syntax != BASESYNTAX && eofmark == NULL)
1475                 synerror("Unterminated quoted string");
1476         if (state[level].category == TSTATE_VAR_OLD ||
1477             state[level].category == TSTATE_VAR_NEW) {
1478                 startlinno = plinno;
1479                 synerror("Missing '}'");
1480         }
1481         if (state != state_static)
1482                 parser_temp_free_upto(state);
1483         USTPUTC('\0', out);
1484         len = out - stackblock();
1485         out = stackblock();
1486         if (eofmark == NULL) {
1487                 if ((c == '>' || c == '<')
1488                  && quotef == 0
1489                  && len <= 2
1490                  && (*out == '\0' || is_digit(*out))) {
1491                         PARSEREDIR();
1492                         return lasttoken = TREDIR;
1493                 } else {
1494                         pungetc();
1495                 }
1496         }
1497         quoteflag = quotef;
1498         backquotelist = bqlist;
1499         grabstackblock(len);
1500         wordtext = out;
1501         return lasttoken = TWORD;
1502 /* end of readtoken routine */
1503
1504
1505 /*
1506  * Check to see whether we are at the end of the here document.  When this
1507  * is called, c is set to the first character of the next input line.  If
1508  * we are at the end of the here document, this routine sets the c to PEOF.
1509  */
1510
1511 checkend: {
1512         if (eofmark) {
1513                 if (striptabs) {
1514                         while (c == '\t')
1515                                 c = pgetc();
1516                 }
1517                 if (c == *eofmark) {
1518                         if (pfgets(line, sizeof line) != NULL) {
1519                                 char *p, *q;
1520
1521                                 p = line;
1522                                 for (q = eofmark + 1 ; *q && *p == *q ; p++, q++);
1523                                 if ((*p == '\0' || *p == '\n') && *q == '\0') {
1524                                         c = PEOF;
1525                                         if (*p == '\n') {
1526                                                 plinno++;
1527                                                 needprompt = doprompt;
1528                                         }
1529                                 } else {
1530                                         pushstring(line, strlen(line), NULL);
1531                                 }
1532                         }
1533                 }
1534         }
1535         goto checkend_return;
1536 }
1537
1538
1539 /*
1540  * Parse a redirection operator.  The variable "out" points to a string
1541  * specifying the fd to be redirected.  The variable "c" contains the
1542  * first character of the redirection operator.
1543  */
1544
1545 parseredir: {
1546         char fd = *out;
1547         union node *np;
1548
1549         np = (union node *)stalloc(sizeof (struct nfile));
1550         if (c == '>') {
1551                 np->nfile.fd = 1;
1552                 c = pgetc();
1553                 if (c == '>')
1554                         np->type = NAPPEND;
1555                 else if (c == '&')
1556                         np->type = NTOFD;
1557                 else if (c == '|')
1558                         np->type = NCLOBBER;
1559                 else {
1560                         np->type = NTO;
1561                         pungetc();
1562                 }
1563         } else {        /* c == '<' */
1564                 np->nfile.fd = 0;
1565                 c = pgetc();
1566                 if (c == '<') {
1567                         if (sizeof (struct nfile) != sizeof (struct nhere)) {
1568                                 np = (union node *)stalloc(sizeof (struct nhere));
1569                                 np->nfile.fd = 0;
1570                         }
1571                         np->type = NHERE;
1572                         heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
1573                         heredoc->here = np;
1574                         if ((c = pgetc()) == '-') {
1575                                 heredoc->striptabs = 1;
1576                         } else {
1577                                 heredoc->striptabs = 0;
1578                                 pungetc();
1579                         }
1580                 } else if (c == '&')
1581                         np->type = NFROMFD;
1582                 else if (c == '>')
1583                         np->type = NFROMTO;
1584                 else {
1585                         np->type = NFROM;
1586                         pungetc();
1587                 }
1588         }
1589         if (fd != '\0')
1590                 np->nfile.fd = digit_val(fd);
1591         redirnode = np;
1592         goto parseredir_return;
1593 }
1594
1595
1596 /*
1597  * Parse a substitution.  At this point, we have read the dollar sign
1598  * and nothing else.
1599  */
1600
1601 parsesub: {
1602         char buf[10];
1603         int subtype;
1604         int typeloc;
1605         int flags;
1606         char *p;
1607         static const char types[] = "}-+?=";
1608         int bracketed_name = 0; /* used to handle ${[0-9]*} variables */
1609         int linno;
1610         int length;
1611         int c1;
1612
1613         c = pgetc();
1614         if (c == '(') { /* $(command) or $((arith)) */
1615                 if (pgetc() == '(') {
1616                         PARSEARITH();
1617                 } else {
1618                         pungetc();
1619                         out = parsebackq(out, &bqlist, 0,
1620                             state[level].syntax == DQSYNTAX &&
1621                             (eofmark == NULL || newvarnest > 0),
1622                             state[level].syntax == DQSYNTAX ||
1623                             state[level].syntax == ARISYNTAX);
1624                 }
1625         } else if (c == '{' || is_name(c) || is_special(c)) {
1626                 USTPUTC(CTLVAR, out);
1627                 typeloc = out - stackblock();
1628                 USTPUTC(VSNORMAL, out);
1629                 subtype = VSNORMAL;
1630                 flags = 0;
1631                 if (c == '{') {
1632                         bracketed_name = 1;
1633                         c = pgetc();
1634                         subtype = 0;
1635                 }
1636 varname:
1637                 if (!is_eof(c) && is_name(c)) {
1638                         length = 0;
1639                         do {
1640                                 STPUTC(c, out);
1641                                 c = pgetc();
1642                                 length++;
1643                         } while (!is_eof(c) && is_in_name(c));
1644                         if (length == 6 &&
1645                             strncmp(out - length, "LINENO", length) == 0) {
1646                                 /* Replace the variable name with the
1647                                  * current line number. */
1648                                 linno = plinno;
1649                                 if (funclinno != 0)
1650                                         linno -= funclinno - 1;
1651                                 snprintf(buf, sizeof(buf), "%d", linno);
1652                                 STADJUST(-6, out);
1653                                 STPUTS(buf, out);
1654                                 flags |= VSLINENO;
1655                         }
1656                 } else if (is_digit(c)) {
1657                         if (bracketed_name) {
1658                                 do {
1659                                         STPUTC(c, out);
1660                                         c = pgetc();
1661                                 } while (is_digit(c));
1662                         } else {
1663                                 STPUTC(c, out);
1664                                 c = pgetc();
1665                         }
1666                 } else if (is_special(c)) {
1667                         c1 = c;
1668                         c = pgetc();
1669                         if (subtype == 0 && c1 == '#') {
1670                                 subtype = VSLENGTH;
1671                                 if (strchr(types, c) == NULL && c != ':' &&
1672                                     c != '#' && c != '%')
1673                                         goto varname;
1674                                 c1 = c;
1675                                 c = pgetc();
1676                                 if (c1 != '}' && c == '}') {
1677                                         pungetc();
1678                                         c = c1;
1679                                         goto varname;
1680                                 }
1681                                 pungetc();
1682                                 c = c1;
1683                                 c1 = '#';
1684                                 subtype = 0;
1685                         }
1686                         USTPUTC(c1, out);
1687                 } else {
1688                         subtype = VSERROR;
1689                         if (c == '}')
1690                                 pungetc();
1691                         else if (c == '\n' || c == PEOF)
1692                                 synerror("Unexpected end of line in substitution");
1693                         else
1694                                 USTPUTC(c, out);
1695                 }
1696                 if (subtype == 0) {
1697                         switch (c) {
1698                         case ':':
1699                                 flags |= VSNUL;
1700                                 c = pgetc();
1701                                 /*FALLTHROUGH*/
1702                         default:
1703                                 p = strchr(types, c);
1704                                 if (p == NULL) {
1705                                         if (c == '\n' || c == PEOF)
1706                                                 synerror("Unexpected end of line in substitution");
1707                                         if (flags == VSNUL)
1708                                                 STPUTC(':', out);
1709                                         STPUTC(c, out);
1710                                         subtype = VSERROR;
1711                                 } else
1712                                         subtype = p - types + VSNORMAL;
1713                                 break;
1714                         case '%':
1715                         case '#':
1716                                 {
1717                                         int cc = c;
1718                                         subtype = c == '#' ? VSTRIMLEFT :
1719                                                              VSTRIMRIGHT;
1720                                         c = pgetc();
1721                                         if (c == cc)
1722                                                 subtype++;
1723                                         else
1724                                                 pungetc();
1725                                         break;
1726                                 }
1727                         }
1728                 } else if (subtype != VSERROR) {
1729                         if (subtype == VSLENGTH && c != '}')
1730                                 subtype = VSERROR;
1731                         pungetc();
1732                 }
1733                 STPUTC('=', out);
1734                 if (state[level].syntax == DQSYNTAX ||
1735                     state[level].syntax == ARISYNTAX)
1736                         flags |= VSQUOTE;
1737                 *(stackblock() + typeloc) = subtype | flags;
1738                 if (subtype != VSNORMAL) {
1739                         if (level + 1 >= maxnest) {
1740                                 maxnest *= 2;
1741                                 if (state == state_static) {
1742                                         state = parser_temp_alloc(
1743                                             maxnest * sizeof(*state));
1744                                         memcpy(state, state_static,
1745                                             MAXNEST_STATIC * sizeof(*state));
1746                                 } else
1747                                         state = parser_temp_realloc(state,
1748                                             maxnest * sizeof(*state));
1749                         }
1750                         level++;
1751                         state[level].parenlevel = 0;
1752                         if (subtype == VSMINUS || subtype == VSPLUS ||
1753                             subtype == VSQUESTION || subtype == VSASSIGN) {
1754                                 /*
1755                                  * For operators that were in the Bourne shell,
1756                                  * inherit the double-quote state.
1757                                  */
1758                                 state[level].syntax = state[level - 1].syntax;
1759                                 state[level].category = TSTATE_VAR_OLD;
1760                         } else {
1761                                 /*
1762                                  * The other operators take a pattern,
1763                                  * so go to BASESYNTAX.
1764                                  * Also, ' and " are now special, even
1765                                  * in here documents.
1766                                  */
1767                                 state[level].syntax = BASESYNTAX;
1768                                 state[level].category = TSTATE_VAR_NEW;
1769                                 newvarnest++;
1770                         }
1771                 }
1772         } else if (c == '\'' && state[level].syntax == BASESYNTAX) {
1773                 /* $'cstylequotes' */
1774                 USTPUTC(CTLQUOTEMARK, out);
1775                 state[level].syntax = SQSYNTAX;
1776                 sqiscstyle = 1;
1777         } else {
1778                 USTPUTC('$', out);
1779                 pungetc();
1780         }
1781         goto parsesub_return;
1782 }
1783
1784
1785 /*
1786  * Parse an arithmetic expansion (indicate start of one and set state)
1787  */
1788 parsearith: {
1789
1790         if (level + 1 >= maxnest) {
1791                 maxnest *= 2;
1792                 if (state == state_static) {
1793                         state = parser_temp_alloc(
1794                             maxnest * sizeof(*state));
1795                         memcpy(state, state_static,
1796                             MAXNEST_STATIC * sizeof(*state));
1797                 } else
1798                         state = parser_temp_realloc(state,
1799                             maxnest * sizeof(*state));
1800         }
1801         level++;
1802         state[level].syntax = ARISYNTAX;
1803         state[level].parenlevel = 0;
1804         state[level].category = TSTATE_ARITH;
1805         USTPUTC(CTLARI, out);
1806         if (state[level - 1].syntax == DQSYNTAX)
1807                 USTPUTC('"',out);
1808         else
1809                 USTPUTC(' ',out);
1810         goto parsearith_return;
1811 }
1812
1813 } /* end of readtoken */
1814
1815
1816
1817 #ifdef mkinit
1818 RESET {
1819         tokpushback = 0;
1820         checkkwd = 0;
1821 }
1822 #endif
1823
1824 /*
1825  * Returns true if the text contains nothing to expand (no dollar signs
1826  * or backquotes).
1827  */
1828
1829 static int
1830 noexpand(char *text)
1831 {
1832         char *p;
1833         char c;
1834
1835         p = text;
1836         while ((c = *p++) != '\0') {
1837                 if ( c == CTLQUOTEMARK)
1838                         continue;
1839                 if (c == CTLESC)
1840                         p++;
1841                 else if (BASESYNTAX[(int)c] == CCTL)
1842                         return 0;
1843         }
1844         return 1;
1845 }
1846
1847
1848 /*
1849  * Return true if the argument is a legal variable name (a letter or
1850  * underscore followed by zero or more letters, underscores, and digits).
1851  */
1852
1853 int
1854 goodname(const char *name)
1855 {
1856         const char *p;
1857
1858         p = name;
1859         if (! is_name(*p))
1860                 return 0;
1861         while (*++p) {
1862                 if (! is_in_name(*p))
1863                         return 0;
1864         }
1865         return 1;
1866 }
1867
1868
1869 int
1870 isassignment(const char *p)
1871 {
1872         if (!is_name(*p))
1873                 return 0;
1874         p++;
1875         for (;;) {
1876                 if (*p == '=')
1877                         return 1;
1878                 else if (!is_in_name(*p))
1879                         return 0;
1880                 p++;
1881         }
1882 }
1883
1884
1885 /*
1886  * Called when an unexpected token is read during the parse.  The argument
1887  * is the token that is expected, or -1 if more than one type of token can
1888  * occur at this point.
1889  */
1890
1891 static void
1892 synexpect(int token)
1893 {
1894         char msg[64];
1895
1896         if (token >= 0) {
1897                 fmtstr(msg, 64, "%s unexpected (expecting %s)",
1898                         tokname[lasttoken], tokname[token]);
1899         } else {
1900                 fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
1901         }
1902         synerror(msg);
1903 }
1904
1905
1906 static void
1907 synerror(const char *msg)
1908 {
1909         if (commandname)
1910                 outfmt(out2, "%s: %d: ", commandname, startlinno);
1911         outfmt(out2, "Syntax error: %s\n", msg);
1912         error(NULL);
1913 }
1914
1915 static void
1916 setprompt(int which)
1917 {
1918         whichprompt = which;
1919
1920 #ifndef NO_HISTORY
1921         if (!el)
1922 #endif
1923         {
1924                 out2str(getprompt(NULL));
1925                 flushout(out2);
1926         }
1927 }
1928
1929 /*
1930  * called by editline -- any expansions to the prompt
1931  *    should be added here.
1932  */
1933 const char *
1934 getprompt(void *unused __unused)
1935 {
1936         static char ps[PROMPTLEN];
1937         const char *fmt;
1938         const char *pwd;
1939         int i, trim;
1940
1941         /*
1942          * Select prompt format.
1943          */
1944         switch (whichprompt) {
1945         case 0:
1946                 fmt = "";
1947                 break;
1948         case 1:
1949                 fmt = ps1val();
1950                 break;
1951         case 2:
1952                 fmt = ps2val();
1953                 break;
1954         default:
1955                 return "??";
1956         }
1957
1958         /*
1959          * Format prompt string.
1960          */
1961         for (i = 0; (i < 127) && (*fmt != '\0'); i++, fmt++)
1962                 if (*fmt == '\\')
1963                         switch (*++fmt) {
1964
1965                                 /*
1966                                  * Hostname.
1967                                  *
1968                                  * \h specifies just the local hostname,
1969                                  * \H specifies fully-qualified hostname.
1970                                  */
1971                         case 'h':
1972                         case 'H':
1973                                 ps[i] = '\0';
1974                                 gethostname(&ps[i], PROMPTLEN - i);
1975                                 /* Skip to end of hostname. */
1976                                 trim = (*fmt == 'h') ? '.' : '\0';
1977                                 while ((ps[i+1] != '\0') && (ps[i+1] != trim))
1978                                         i++;
1979                                 break;
1980
1981                                 /*
1982                                  * Working directory.
1983                                  *
1984                                  * \W specifies just the final component,
1985                                  * \w specifies the entire path.
1986                                  */
1987                         case 'W':
1988                         case 'w':
1989                                 pwd = lookupvar("PWD");
1990                                 if (pwd == NULL)
1991                                         pwd = "?";
1992                                 if (*fmt == 'W' &&
1993                                     *pwd == '/' && pwd[1] != '\0')
1994                                         strlcpy(&ps[i], strrchr(pwd, '/') + 1,
1995                                             PROMPTLEN - i);
1996                                 else
1997                                         strlcpy(&ps[i], pwd, PROMPTLEN - i);
1998                                 /* Skip to end of path. */
1999                                 while (ps[i + 1] != '\0')
2000                                         i++;
2001                                 break;
2002
2003                                 /*
2004                                  * Superuser status.
2005                                  *
2006                                  * '$' for normal users, '#' for root.
2007                                  */
2008                         case '$':
2009                                 ps[i] = (geteuid() != 0) ? '$' : '#';
2010                                 break;
2011
2012                                 /*
2013                                  * A literal \.
2014                                  */
2015                         case '\\':
2016                                 ps[i] = '\\';
2017                                 break;
2018
2019                                 /*
2020                                  * Emit unrecognized formats verbatim.
2021                                  */
2022                         default:
2023                                 ps[i++] = '\\';
2024                                 ps[i] = *fmt;
2025                                 break;
2026                         }
2027                 else
2028                         ps[i] = *fmt;
2029         ps[i] = '\0';
2030         return (ps);
2031 }
2032
2033
2034 const char *
2035 expandstr(char *ps)
2036 {
2037         union node n;
2038         struct jmploc jmploc;
2039         struct jmploc *const savehandler = handler;
2040         const int saveprompt = doprompt;
2041         struct parsefile *const savetopfile = getcurrentfile();
2042         struct parser_temp *const saveparser_temp = parser_temp;
2043         const char *result = NULL;
2044
2045         if (!setjmp(jmploc.loc)) {
2046                 handler = &jmploc;
2047                 parser_temp = NULL;
2048                 setinputstring(ps, 1);
2049                 doprompt = 0;
2050                 readtoken1(pgetc(), DQSYNTAX, __DECONST(char *, "\n\n"), 0);
2051                 if (backquotelist != NULL)
2052                         error("Command substitution not allowed here");
2053
2054                 n.narg.type = NARG;
2055                 n.narg.next = NULL;
2056                 n.narg.text = wordtext;
2057                 n.narg.backquote = backquotelist;
2058
2059                 expandarg(&n, NULL, 0);
2060                 result = stackblock();
2061                 INTOFF;
2062         }
2063         handler = savehandler;
2064         doprompt = saveprompt;
2065         popfilesupto(savetopfile);
2066         if (parser_temp != saveparser_temp) {
2067                 parser_temp_free_all();
2068                 parser_temp = saveparser_temp;
2069         }
2070         if (result != NULL) {
2071                 INTON;
2072         } else if (exception == EXINT)
2073                 raise(SIGINT);
2074         return result;
2075 }