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 1.105 2011/02/05 15:02:19 jilles Exp $
  38  */
  39
  40 #include <stdio.h>
  41 #include <stdlib.h>
  42 #include <unistd.h>
  43
  44 #include "shell.h"
  45 #include "parser.h"
  46 #include "nodes.h"
  47 #include "expand.h"     /* defines rmescapes() */
  48 #include "syntax.h"
  49 #include "options.h"
  50 #include "input.h"
  51 #include "output.h"
  52 #include "var.h"
  53 #include "error.h"
  54 #include "memalloc.h"
  55 #include "mystring.h"
  56 #include "alias.h"
  57 #include "show.h"
  58 #include "eval.h"
  59 #include "exec.h"       /* to check for special builtins */
  60 #ifndef NO_HISTORY
  61 #include "myhistedit.h"
  62 #endif
  63
  64 /*
  65  * Shell command parser.
  66  */
  67
  68 #define EOFMARKLEN      79
  69 #define PROMPTLEN       128
  70
  71 /* values of checkkwd variable */
  72 #define CHKALIAS        0x1
  73 #define CHKKWD          0x2
  74 #define CHKNL           0x4
  75
  76 /* values returned by readtoken */
  77 #include "token.h"
  78
  79
  80
  81 struct heredoc {
  82         struct heredoc *next;   /* next here document in list */
  83         union node *here;               /* redirection node */
  84         char *eofmark;          /* string indicating end of input */
  85         int striptabs;          /* if set, strip leading tabs */
  86 };
  87
  88 struct parser_temp {
  89         struct parser_temp *next;
  90         void *data;
  91 };
  92
  93
  94 static struct heredoc *heredoclist;     /* list of here documents to read */
  95 static int doprompt;            /* if set, prompt the user */
  96 static int needprompt;          /* true if interactive and at start of line */
  97 static int lasttoken;           /* last token read */
  98 MKINIT int tokpushback;         /* last token pushed back */
  99 static char *wordtext;          /* text of last word returned by readtoken */
 100 MKINIT int checkkwd;            /* 1 == check for kwds, 2 == also eat newlines */
 101 static struct nodelist *backquotelist;
 102 static union node *redirnode;
 103 static struct heredoc *heredoc;
 104 static int quoteflag;           /* set if (part of) last token was quoted */
 105 static int startlinno;          /* line # where last token started */
 106 static int funclinno;           /* line # where the current function started */
 107 static struct parser_temp *parser_temp;
 108
 109
 110 static union node *list(int, int);
 111 static union node *andor(void);
 112 static union node *pipeline(void);
 113 static union node *command(void);
 114 static union node *simplecmd(union node **, union node *);
 115 static union node *makename(void);
 116 static void parsefname(void);
 117 static void parseheredoc(void);
 118 static int peektoken(void);
 119 static int readtoken(void);
 120 static int xxreadtoken(void);
 121 static int readtoken1(int, char const *, char *, int);
 122 static int noexpand(char *);
 123 static void synexpect(int) __dead2;
 124 static void synerror(const char *) __dead2;
 125 static void setprompt(int);
 126
 127
 128 static void *
 129 parser_temp_alloc(size_t len)
 130 {
 131         struct parser_temp *t;
 132
 133         INTOFF;
 134         t = ckmalloc(sizeof(*t));
 135         t->data = NULL;
 136         t->next = parser_temp;
 137         parser_temp = t;
 138         t->data = ckmalloc(len);
 139         INTON;
 140         return t->data;
 141 }
 142
 143
 144 static void *
 145 parser_temp_realloc(void *ptr, size_t len)
 146 {
 147         struct parser_temp *t;
 148
 149         INTOFF;
 150         t = parser_temp;
 151         if (ptr != t->data)
 152                 error("bug: parser_temp_realloc misused");
 153         t->data = ckrealloc(t->data, len);
 154         INTON;
 155         return t->data;
 156 }
 157
 158
 159 static void
 160 parser_temp_free_upto(void *ptr)
 161 {
 162         struct parser_temp *t;
 163         int done = 0;
 164
 165         INTOFF;
 166         while (parser_temp != NULL && !done) {
 167                 t = parser_temp;
 168                 parser_temp = t->next;
 169                 done = t->data == ptr;
 170                 ckfree(t->data);
 171                 ckfree(t);
 172         }
 173         INTON;
 174         if (!done)
 175                 error("bug: parser_temp_free_upto misused");
 176 }
 177
 178
 179 static void
 180 parser_temp_free_all(void)
 181 {
 182         struct parser_temp *t;
 183
 184         INTOFF;
 185         while (parser_temp != NULL) {
 186                 t = parser_temp;
 187                 parser_temp = t->next;
 188                 ckfree(t->data);
 189                 ckfree(t);
 190         }
 191         INTON;
 192 }
 193
 194
 195 /*
 196  * Read and parse a command.  Returns NEOF on end of file.  (NULL is a
 197  * valid parse tree indicating a blank line.)
 198  */
 199
 200 union node *
 201 parsecmd(int interact)
 202 {
 203         int t;
 204
 205         /* This assumes the parser is not re-entered,
 206          * which could happen if we add command substitution on PS1/PS2.
 207          */
 208         parser_temp_free_all();
 209         heredoclist = NULL;
 210
 211         tokpushback = 0;
 212         doprompt = interact;
 213         if (doprompt)
 214                 setprompt(1);
 215         else
 216                 setprompt(0);
 217         needprompt = 0;
 218         t = readtoken();
 219         if (t == TEOF)
 220                 return NEOF;
 221         if (t == TNL)
 222                 return NULL;
 223         tokpushback++;
 224         return list(1, 1);
 225 }
 226
 227
 228 static union node *
 229 list(int nlflag, int erflag)
 230 {
 231         union node *ntop, *n1, *n2, *n3;
 232         int tok;
 233
 234         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 235         if (!nlflag && !erflag && tokendlist[peektoken()])
 236                 return NULL;
 237         ntop = n1 = NULL;
 238         for (;;) {
 239                 n2 = andor();
 240                 tok = readtoken();
 241                 if (tok == TBACKGND) {
 242                         if (n2->type == NCMD || n2->type == NPIPE) {
 243                                 n2->ncmd.backgnd = 1;
 244                         } else if (n2->type == NREDIR) {
 245                                 n2->type = NBACKGND;
 246                         } else {
 247                                 n3 = (union node *)stalloc(sizeof (struct nredir));
 248                                 n3->type = NBACKGND;
 249                                 n3->nredir.n = n2;
 250                                 n3->nredir.redirect = NULL;
 251                                 n2 = n3;
 252                         }
 253                 }
 254                 if (ntop == NULL)
 255                         ntop = n2;
 256                 else if (n1 == NULL) {
 257                         n1 = (union node *)stalloc(sizeof (struct nbinary));
 258                         n1->type = NSEMI;
 259                         n1->nbinary.ch1 = ntop;
 260                         n1->nbinary.ch2 = n2;
 261                         ntop = n1;
 262                 }
 263                 else {
 264                         n3 = (union node *)stalloc(sizeof (struct nbinary));
 265                         n3->type = NSEMI;
 266                         n3->nbinary.ch1 = n1->nbinary.ch2;
 267                         n3->nbinary.ch2 = n2;
 268                         n1->nbinary.ch2 = n3;
 269                         n1 = n3;
 270                 }
 271                 switch (tok) {
 272                 case TBACKGND:
 273                 case TSEMI:
 274                         tok = readtoken();
 275                         /* FALLTHROUGH */
 276                 case TNL:
 277                         if (tok == TNL) {
 278                                 parseheredoc();
 279                                 if (nlflag)
 280                                         return ntop;
 281                         } else if (tok == TEOF && nlflag) {
 282                                 parseheredoc();
 283                                 return ntop;
 284                         } else {
 285                                 tokpushback++;
 286                         }
 287                         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 288                         if (!nlflag && !erflag && tokendlist[peektoken()])
 289                                 return ntop;
 290                         break;
 291                 case TEOF:
 292                         if (heredoclist)
 293                                 parseheredoc();
 294                         else
 295                                 pungetc();              /* push back EOF on input */
 296                         return ntop;
 297                 default:
 298                         if (nlflag || erflag)
 299                                 synexpect(-1);
 300                         tokpushback++;
 301                         return ntop;
 302                 }
 303         }
 304 }
 305
 306
 307
 308 static union node *
 309 andor(void)
 310 {
 311         union node *n1, *n2, *n3;
 312         int t;
 313
 314         n1 = pipeline();
 315         for (;;) {
 316                 if ((t = readtoken()) == TAND) {
 317                         t = NAND;
 318                 } else if (t == TOR) {
 319                         t = NOR;
 320                 } else {
 321                         tokpushback++;
 322                         return n1;
 323                 }
 324                 n2 = pipeline();
 325                 n3 = (union node *)stalloc(sizeof (struct nbinary));
 326                 n3->type = t;
 327                 n3->nbinary.ch1 = n1;
 328                 n3->nbinary.ch2 = n2;
 329                 n1 = n3;
 330         }
 331 }
 332
 333
 334
 335 static union node *
 336 pipeline(void)
 337 {
 338         union node *n1, *n2, *pipenode;
 339         struct nodelist *lp, *prev;
 340         int negate, t;
 341
 342         negate = 0;
 343         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 344         TRACE(("pipeline: entered\n"));
 345         while (readtoken() == TNOT)
 346                 negate = !negate;
 347         tokpushback++;
 348         n1 = command();
 349         if (readtoken() == TPIPE) {
 350                 pipenode = (union node *)stalloc(sizeof (struct npipe));
 351                 pipenode->type = NPIPE;
 352                 pipenode->npipe.backgnd = 0;
 353                 lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 354                 pipenode->npipe.cmdlist = lp;
 355                 lp->n = n1;
 356                 do {
 357                         prev = lp;
 358                         lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 359                         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 360                         t = readtoken();
 361                         tokpushback++;
 362                         if (t == TNOT)
 363                                 lp->n = pipeline();
 364                         else
 365                                 lp->n = command();
 366                         prev->next = lp;
 367                 } while (readtoken() == TPIPE);
 368                 lp->next = NULL;
 369                 n1 = pipenode;
 370         }
 371         tokpushback++;
 372         if (negate) {
 373                 n2 = (union node *)stalloc(sizeof (struct nnot));
 374                 n2->type = NNOT;
 375                 n2->nnot.com = n1;
 376                 return n2;
 377         } else
 378                 return n1;
 379 }
 380
 381
 382
 383 static union node *
 384 command(void)
 385 {
 386         union node *n1, *n2;
 387         union node *ap, **app;
 388         union node *cp, **cpp;
 389         union node *redir, **rpp;
 390         int t;
 391         int is_subshell;
 392
 393         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 394         is_subshell = 0;
 395         redir = NULL;
 396         n1 = NULL;
 397         rpp = &redir;
 398
 399         /* Check for redirection which may precede command */
 400         while (readtoken() == TREDIR) {
 401                 *rpp = n2 = redirnode;
 402                 rpp = &n2->nfile.next;
 403                 parsefname();
 404         }
 405         tokpushback++;
 406
 407         switch (readtoken()) {
 408         case TIF:
 409                 n1 = (union node *)stalloc(sizeof (struct nif));
 410                 n1->type = NIF;
 411                 if ((n1->nif.test = list(0, 0)) == NULL)
 412                         synexpect(-1);
 413                 if (readtoken() != TTHEN)
 414                         synexpect(TTHEN);
 415                 n1->nif.ifpart = list(0, 0);
 416                 n2 = n1;
 417                 while (readtoken() == TELIF) {
 418                         n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
 419                         n2 = n2->nif.elsepart;
 420                         n2->type = NIF;
 421                         if ((n2->nif.test = list(0, 0)) == NULL)
 422                                 synexpect(-1);
 423                         if (readtoken() != TTHEN)
 424                                 synexpect(TTHEN);
 425                         n2->nif.ifpart = list(0, 0);
 426                 }
 427                 if (lasttoken == TELSE)
 428                         n2->nif.elsepart = list(0, 0);
 429                 else {
 430                         n2->nif.elsepart = NULL;
 431                         tokpushback++;
 432                 }
 433                 if (readtoken() != TFI)
 434                         synexpect(TFI);
 435                 checkkwd = CHKKWD | CHKALIAS;
 436                 break;
 437         case TWHILE:
 438         case TUNTIL: {
 439                 int got;
 440                 n1 = (union node *)stalloc(sizeof (struct nbinary));
 441                 n1->type = (lasttoken == TWHILE)? NWHILE : NUNTIL;
 442                 if ((n1->nbinary.ch1 = list(0, 0)) == NULL)
 443                         synexpect(-1);
 444                 if ((got=readtoken()) != TDO) {
 445 TRACE(("expecting DO got %s %s\n", tokname[got], got == TWORD ? wordtext : ""));
 446                         synexpect(TDO);
 447                 }
 448                 n1->nbinary.ch2 = list(0, 0);
 449                 if (readtoken() != TDONE)
 450                         synexpect(TDONE);
 451                 checkkwd = CHKKWD | CHKALIAS;
 452                 break;
 453         }
 454         case TFOR:
 455                 if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
 456                         synerror("Bad for loop variable");
 457                 n1 = (union node *)stalloc(sizeof (struct nfor));
 458                 n1->type = NFOR;
 459                 n1->nfor.var = wordtext;
 460                 while (readtoken() == TNL)
 461                         ;
 462                 if (lasttoken == TWORD && ! quoteflag && equal(wordtext, "in")) {
 463                         app = &ap;
 464                         while (readtoken() == TWORD) {
 465                                 n2 = (union node *)stalloc(sizeof (struct narg));
 466                                 n2->type = NARG;
 467                                 n2->narg.text = wordtext;
 468                                 n2->narg.backquote = backquotelist;
 469                                 *app = n2;
 470                                 app = &n2->narg.next;
 471                         }
 472                         *app = NULL;
 473                         n1->nfor.args = ap;
 474                         if (lasttoken != TNL && lasttoken != TSEMI)
 475                                 synexpect(-1);
 476                 } else {
 477                         static char argvars[5] = {
 478                                 CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'
 479                         };
 480                         n2 = (union node *)stalloc(sizeof (struct narg));
 481                         n2->type = NARG;
 482                         n2->narg.text = argvars;
 483                         n2->narg.backquote = NULL;
 484                         n2->narg.next = NULL;
 485                         n1->nfor.args = n2;
 486                         /*
 487                          * Newline or semicolon here is optional (but note
 488                          * that the original Bourne shell only allowed NL).
 489                          */
 490                         if (lasttoken != TNL && lasttoken != TSEMI)
 491                                 tokpushback++;
 492                 }
 493                 checkkwd = CHKNL | CHKKWD | CHKALIAS;
 494                 if ((t = readtoken()) == TDO)
 495                         t = TDONE;
 496                 else if (t == TBEGIN)
 497                         t = TEND;
 498                 else
 499                         synexpect(-1);
 500                 n1->nfor.body = list(0, 0);
 501                 if (readtoken() != t)
 502                         synexpect(t);
 503                 checkkwd = CHKKWD | CHKALIAS;
 504                 break;
 505         case TCASE:
 506                 n1 = (union node *)stalloc(sizeof (struct ncase));
 507                 n1->type = NCASE;
 508                 if (readtoken() != TWORD)
 509                         synexpect(TWORD);
 510                 n1->ncase.expr = n2 = (union node *)stalloc(sizeof (struct narg));
 511                 n2->type = NARG;
 512                 n2->narg.text = wordtext;
 513                 n2->narg.backquote = backquotelist;
 514                 n2->narg.next = NULL;
 515                 while (readtoken() == TNL);
 516                 if (lasttoken != TWORD || ! equal(wordtext, "in"))
 517                         synerror("expecting \"in\"");
 518                 cpp = &n1->ncase.cases;
 519                 checkkwd = CHKNL | CHKKWD, readtoken();
 520                 while (lasttoken != TESAC) {
 521                         *cpp = cp = (union node *)stalloc(sizeof (struct nclist));
 522                         cp->type = NCLIST;
 523                         app = &cp->nclist.pattern;
 524                         if (lasttoken == TLP)
 525                                 readtoken();
 526                         for (;;) {
 527                                 *app = ap = (union node *)stalloc(sizeof (struct narg));
 528                                 ap->type = NARG;
 529                                 ap->narg.text = wordtext;
 530                                 ap->narg.backquote = backquotelist;
 531                                 checkkwd = CHKNL | CHKKWD;
 532                                 if (readtoken() != TPIPE)
 533                                         break;
 534                                 app = &ap->narg.next;
 535                                 readtoken();
 536                         }
 537                         ap->narg.next = NULL;
 538                         if (lasttoken != TRP)
 539                                 synexpect(TRP);
 540                         cp->nclist.body = list(0, 0);
 541
 542                         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 543                         if ((t = readtoken()) != TESAC) {
 544                                 if (t != TENDCASE)
 545                                         synexpect(TENDCASE);
 546                                 else
 547                                         checkkwd = CHKNL | CHKKWD, readtoken();
 548                         }
 549                         cpp = &cp->nclist.next;
 550                 }
 551                 *cpp = NULL;
 552                 checkkwd = CHKKWD | CHKALIAS;
 553                 break;
 554         case TLP:
 555                 n1 = (union node *)stalloc(sizeof (struct nredir));
 556                 n1->type = NSUBSHELL;
 557                 n1->nredir.n = list(0, 0);
 558                 n1->nredir.redirect = NULL;
 559                 if (readtoken() != TRP)
 560                         synexpect(TRP);
 561                 checkkwd = CHKKWD | CHKALIAS;
 562                 is_subshell = 1;
 563                 break;
 564         case TBEGIN:
 565                 n1 = list(0, 0);
 566                 if (readtoken() != TEND)
 567                         synexpect(TEND);
 568                 checkkwd = CHKKWD | CHKALIAS;
 569                 break;
 570         /* Handle an empty command like other simple commands.  */
 571         case TBACKGND:
 572         case TSEMI:
 573         case TAND:
 574         case TOR:
 575                 /*
 576                  * An empty command before a ; doesn't make much sense, and
 577                  * should certainly be disallowed in the case of `if ;'.
 578                  */
 579                 if (!redir)
 580                         synexpect(-1);
 581         case TNL:
 582         case TEOF:
 583         case TWORD:
 584         case TRP:
 585                 tokpushback++;
 586                 n1 = simplecmd(rpp, redir);
 587                 return n1;
 588         default:
 589                 synexpect(-1);
 590         }
 591
 592         /* Now check for redirection which may follow command */
 593         while (readtoken() == TREDIR) {
 594                 *rpp = n2 = redirnode;
 595                 rpp = &n2->nfile.next;
 596                 parsefname();
 597         }
 598         tokpushback++;
 599         *rpp = NULL;
 600         if (redir) {
 601                 if (!is_subshell) {
 602                         n2 = (union node *)stalloc(sizeof (struct nredir));
 603                         n2->type = NREDIR;
 604                         n2->nredir.n = n1;
 605                         n1 = n2;
 606                 }
 607                 n1->nredir.redirect = redir;
 608         }
 609
 610         return n1;
 611 }
 612
 613
 614 static union node *
 615 simplecmd(union node **rpp, union node *redir)
 616 {
 617         union node *args, **app;
 618         union node **orig_rpp = rpp;
 619         union node *n = NULL;
 620         int special;
 621
 622         /* If we don't have any redirections already, then we must reset */
 623         /* rpp to be the address of the local redir variable.  */
 624         if (redir == 0)
 625                 rpp = &redir;
 626
 627         args = NULL;
 628         app = &args;
 629         /*
 630          * We save the incoming value, because we need this for shell
 631          * functions.  There can not be a redirect or an argument between
 632          * the function name and the open parenthesis.
 633          */
 634         orig_rpp = rpp;
 635
 636         for (;;) {
 637                 if (readtoken() == TWORD) {
 638                         n = (union node *)stalloc(sizeof (struct narg));
 639                         n->type = NARG;
 640                         n->narg.text = wordtext;
 641                         n->narg.backquote = backquotelist;
 642                         *app = n;
 643                         app = &n->narg.next;
 644                 } else if (lasttoken == TREDIR) {
 645                         *rpp = n = redirnode;
 646                         rpp = &n->nfile.next;
 647                         parsefname();   /* read name of redirection file */
 648                 } else if (lasttoken == TLP && app == &args->narg.next
 649                                             && rpp == orig_rpp) {
 650                         /* We have a function */
 651                         if (readtoken() != TRP)
 652                                 synexpect(TRP);
 653                         funclinno = plinno;
 654                         /*
 655                          * - Require plain text.
 656                          * - Functions with '/' cannot be called.
 657                          * - Reject name=().
 658                          * - Reject ksh extended glob patterns.
 659                          */
 660                         if (!noexpand(n->narg.text) || quoteflag ||
 661                             strchr(n->narg.text, '/') ||
 662                             strchr("!%*+-=?@}~",
 663                                 n->narg.text[strlen(n->narg.text) - 1]))
 664                                 synerror("Bad function name");
 665                         rmescapes(n->narg.text);
 666                         if (find_builtin(n->narg.text, &special) >= 0 &&
 667                             special)
 668                                 synerror("Cannot override a special builtin with a function");
 669                         n->type = NDEFUN;
 670                         n->narg.next = command();
 671                         funclinno = 0;
 672                         return n;
 673                 } else {
 674                         tokpushback++;
 675                         break;
 676                 }
 677         }
 678         *app = NULL;
 679         *rpp = NULL;
 680         n = (union node *)stalloc(sizeof (struct ncmd));
 681         n->type = NCMD;
 682         n->ncmd.backgnd = 0;
 683         n->ncmd.args = args;
 684         n->ncmd.redirect = redir;
 685         return n;
 686 }
 687
 688 static union node *
 689 makename(void)
 690 {
 691         union node *n;
 692
 693         n = (union node *)stalloc(sizeof (struct narg));
 694         n->type = NARG;
 695         n->narg.next = NULL;
 696         n->narg.text = wordtext;
 697         n->narg.backquote = backquotelist;
 698         return n;
 699 }
 700
 701 void
 702 fixredir(union node *n, const char *text, int err)
 703 {
 704         TRACE(("Fix redir %s %d\n", text, err));
 705         if (!err)
 706                 n->ndup.vname = NULL;
 707
 708         if (is_digit(text[0]) && text[1] == '\0')
 709                 n->ndup.dupfd = digit_val(text[0]);
 710         else if (text[0] == '-' && text[1] == '\0')
 711                 n->ndup.dupfd = -1;
 712         else {
 713
 714                 if (err)
 715                         synerror("Bad fd number");
 716                 else
 717                         n->ndup.vname = makename();
 718         }
 719 }
 720
 721
 722 static void
 723 parsefname(void)
 724 {
 725         union node *n = redirnode;
 726
 727         if (readtoken() != TWORD)
 728                 synexpect(-1);
 729         if (n->type == NHERE) {
 730                 struct heredoc *here = heredoc;
 731                 struct heredoc *p;
 732                 int i;
 733
 734                 if (quoteflag == 0)
 735                         n->type = NXHERE;
 736                 TRACE(("Here document %d\n", n->type));
 737                 if (here->striptabs) {
 738                         while (*wordtext == '\t')
 739                                 wordtext++;
 740                 }
 741                 if (! noexpand(wordtext) || (i = strlen(wordtext)) == 0 || i > EOFMARKLEN)
 742                         synerror("Illegal eof marker for << redirection");
 743                 rmescapes(wordtext);
 744                 here->eofmark = wordtext;
 745                 here->next = NULL;
 746                 if (heredoclist == NULL)
 747                         heredoclist = here;
 748                 else {
 749                         for (p = heredoclist ; p->next ; p = p->next);
 750                         p->next = here;
 751                 }
 752         } else if (n->type == NTOFD || n->type == NFROMFD) {
 753                 fixredir(n, wordtext, 0);
 754         } else {
 755                 n->nfile.fname = makename();
 756         }
 757 }
 758
 759
 760 /*
 761  * Input any here documents.
 762  */
 763
 764 static void
 765 parseheredoc(void)
 766 {
 767         struct heredoc *here;
 768         union node *n;
 769
 770         while (heredoclist) {
 771                 here = heredoclist;
 772                 heredoclist = here->next;
 773                 if (needprompt) {
 774                         setprompt(2);
 775                         needprompt = 0;
 776                 }
 777                 readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
 778                                 here->eofmark, here->striptabs);
 779                 n = (union node *)stalloc(sizeof (struct narg));
 780                 n->narg.type = NARG;
 781                 n->narg.next = NULL;
 782                 n->narg.text = wordtext;
 783                 n->narg.backquote = backquotelist;
 784                 here->here->nhere.doc = n;
 785         }
 786 }
 787
 788 static int
 789 peektoken(void)
 790 {
 791         int t;
 792
 793         t = readtoken();
 794         tokpushback++;
 795         return (t);
 796 }
 797
 798 static int
 799 readtoken(void)
 800 {
 801         int t;
 802         struct alias *ap;
 803 #ifdef DEBUG
 804         int alreadyseen = tokpushback;
 805 #endif
 806
 807         top:
 808         t = xxreadtoken();
 809
 810         /*
 811          * eat newlines
 812          */
 813         if (checkkwd & CHKNL) {
 814                 while (t == TNL) {
 815                         parseheredoc();
 816                         t = xxreadtoken();
 817                 }
 818         }
 819
 820         /*
 821          * check for keywords and aliases
 822          */
 823         if (t == TWORD && !quoteflag)
 824         {
 825                 const char * const *pp;
 826
 827                 if (checkkwd & CHKKWD)
 828                         for (pp = parsekwd; *pp; pp++) {
 829                                 if (**pp == *wordtext && equal(*pp, wordtext))
 830                                 {
 831                                         lasttoken = t = pp - parsekwd + KWDOFFSET;
 832                                         TRACE(("keyword %s recognized\n", tokname[t]));
 833                                         goto out;
 834                                 }
 835                         }
 836                 if (checkkwd & CHKALIAS &&
 837                     (ap = lookupalias(wordtext, 1)) != NULL) {
 838                         pushstring(ap->val, strlen(ap->val), ap);
 839                         goto top;
 840                 }
 841         }
 842 out:
 843         if (t != TNOT)
 844                 checkkwd = 0;
 845
 846 #ifdef DEBUG
 847         if (!alreadyseen)
 848             TRACE(("token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 849         else
 850             TRACE(("reread token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 851 #endif
 852         return (t);
 853 }
 854
 855
 856 /*
 857  * Read the next input token.
 858  * If the token is a word, we set backquotelist to the list of cmds in
 859  *      backquotes.  We set quoteflag to true if any part of the word was
 860  *      quoted.
 861  * If the token is TREDIR, then we set redirnode to a structure containing
 862  *      the redirection.
 863  * In all cases, the variable startlinno is set to the number of the line
 864  *      on which the token starts.
 865  *
 866  * [Change comment:  here documents and internal procedures]
 867  * [Readtoken shouldn't have any arguments.  Perhaps we should make the
 868  *  word parsing code into a separate routine.  In this case, readtoken
 869  *  doesn't need to have any internal procedures, but parseword does.
 870  *  We could also make parseoperator in essence the main routine, and
 871  *  have parseword (readtoken1?) handle both words and redirection.]
 872  */
 873
 874 #define RETURN(token)   return lasttoken = token
 875
 876 static int
 877 xxreadtoken(void)
 878 {
 879         int c;
 880
 881         if (tokpushback) {
 882                 tokpushback = 0;
 883                 return lasttoken;
 884         }
 885         if (needprompt) {
 886                 setprompt(2);
 887                 needprompt = 0;
 888         }
 889         startlinno = plinno;
 890         for (;;) {      /* until token or start of word found */
 891                 c = pgetc_macro();
 892                 switch (c) {
 893                 case ' ': case '\t':
 894                         continue;
 895                 case '#':
 896                         while ((c = pgetc()) != '\n' && c != PEOF);
 897                         pungetc();
 898                         continue;
 899                 case '\\':
 900                         if (pgetc() == '\n') {
 901                                 startlinno = ++plinno;
 902                                 if (doprompt)
 903                                         setprompt(2);
 904                                 else
 905                                         setprompt(0);
 906                                 continue;
 907                         }
 908                         pungetc();
 909                         goto breakloop;
 910                 case '\n':
 911                         plinno++;
 912                         needprompt = doprompt;
 913                         RETURN(TNL);
 914                 case PEOF:
 915                         RETURN(TEOF);
 916                 case '&':
 917                         if (pgetc() == '&')
 918                                 RETURN(TAND);
 919                         pungetc();
 920                         RETURN(TBACKGND);
 921                 case '|':
 922                         if (pgetc() == '|')
 923                                 RETURN(TOR);
 924                         pungetc();
 925                         RETURN(TPIPE);
 926                 case ';':
 927                         if (pgetc() == ';')
 928                                 RETURN(TENDCASE);
 929                         pungetc();
 930                         RETURN(TSEMI);
 931                 case '(':
 932                         RETURN(TLP);
 933                 case ')':
 934                         RETURN(TRP);
 935                 default:
 936                         goto breakloop;
 937                 }
 938         }
 939 breakloop:
 940         return readtoken1(c, BASESYNTAX, NULL, 0);
 941 #undef RETURN
 942 }
 943
 944
 945 #define MAXNEST_STATIC 8
 946 struct tokenstate
 947 {
 948         const char *syntax; /* *SYNTAX */
 949         int parenlevel; /* levels of parentheses in arithmetic */
 950         enum tokenstate_category
 951         {
 952                 TSTATE_TOP,
 953                 TSTATE_VAR_OLD, /* ${var+-=?}, inherits dquotes */
 954                 TSTATE_VAR_NEW, /* other ${var...}, own dquote state */
 955                 TSTATE_ARITH
 956         } category;
 957 };
 958
 959
 960 /*
 961  * Called to parse command substitutions.
 962  */
 963
 964 static char *
 965 parsebackq(char *out, struct nodelist **pbqlist,
 966     int oldstyle, int dblquote, int quoted)
 967 {
 968         struct nodelist **nlpp;
 969         union node *n;
 970         char *volatile str;
 971         struct jmploc jmploc;
 972         struct jmploc *const savehandler = handler;
 973         int savelen;
 974         int saveprompt;
 975         const int bq_startlinno = plinno;
 976         char *volatile ostr = NULL;
 977         struct parsefile *const savetopfile = getcurrentfile();
 978         struct heredoc *const saveheredoclist = heredoclist;
 979         struct heredoc *here;
 980
 981         str = NULL;
 982         if (setjmp(jmploc.loc)) {
 983                 popfilesupto(savetopfile);
 984                 if (str)
 985                         ckfree(str);
 986                 if (ostr)
 987                         ckfree(ostr);
 988                 heredoclist = saveheredoclist;
 989                 handler = savehandler;
 990                 if (exception == EXERROR) {
 991                         startlinno = bq_startlinno;
 992                         synerror("Error in command substitution");
 993                 }
 994                 longjmp(handler->loc, 1);
 995         }
 996         INTOFF;
 997         savelen = out - stackblock();
 998         if (savelen > 0) {
 999                 str = ckmalloc(savelen);
1000                 memcpy(str, stackblock(), savelen);
1001         }
1002         handler = &jmploc;
1003         heredoclist = NULL;
1004         INTON;
1005         if (oldstyle) {
1006                 /*
1007                  * We must read until the closing backquote, giving special
1008                  * treatment to some slashes, and then push the string and
1009                  * reread it as input, interpreting it normally.
1010                  */
1011                 char *oout;
1012                 int c, olen;
1013
1014                 STARTSTACKSTR(oout);
1015                 for (;;) {
1016                         if (needprompt) {
1017                                 setprompt(2);
1018                                 needprompt = 0;
1019                         }
1020                         CHECKSTRSPACE(2, oout);
1021                         switch (c = pgetc()) {
1022                         case '`':
1023                                 goto done;
1024
1025                         case '\\':
1026                                 if ((c = pgetc()) == '\n') {
1027                                         plinno++;
1028                                         if (doprompt)
1029                                                 setprompt(2);
1030                                         else
1031                                                 setprompt(0);
1032                                         /*
1033                                          * If eating a newline, avoid putting
1034                                          * the newline into the new character
1035                                          * stream (via the USTPUTC after the
1036                                          * switch).
1037                                          */
1038                                         continue;
1039                                 }
1040                                 if (c != '\\' && c != '`' && c != '$'
1041                                     && (!dblquote || c != '"'))
1042                                         USTPUTC('\\', oout);
1043                                 break;
1044
1045                         case '\n':
1046                                 plinno++;
1047                                 needprompt = doprompt;
1048                                 break;
1049
1050                         case PEOF:
1051                                 startlinno = plinno;
1052                                 synerror("EOF in backquote substitution");
1053                                 break;
1054
1055                         default:
1056                                 break;
1057                         }
1058                         USTPUTC(c, oout);
1059                 }
1060 done:
1061                 USTPUTC('\0', oout);
1062                 olen = oout - stackblock();
1063                 INTOFF;
1064                 ostr = ckmalloc(olen);
1065                 memcpy(ostr, stackblock(), olen);
1066                 setinputstring(ostr, 1);
1067                 INTON;
1068         }
1069         nlpp = pbqlist;
1070         while (*nlpp)
1071                 nlpp = &(*nlpp)->next;
1072         *nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
1073         (*nlpp)->next = NULL;
1074
1075         if (oldstyle) {
1076                 saveprompt = doprompt;
1077                 doprompt = 0;
1078         }
1079
1080         n = list(0, oldstyle);
1081
1082         if (oldstyle)
1083                 doprompt = saveprompt;
1084         else {
1085                 if (readtoken() != TRP)
1086                         synexpect(TRP);
1087         }
1088
1089         (*nlpp)->n = n;
1090         if (oldstyle) {
1091                 /*
1092                  * Start reading from old file again, ignoring any pushed back
1093                  * tokens left from the backquote parsing
1094                  */
1095                 popfile();
1096                 tokpushback = 0;
1097         }
1098         STARTSTACKSTR(out);
1099         CHECKSTRSPACE(savelen + 1, out);
1100         INTOFF;
1101         if (str) {
1102                 memcpy(out, str, savelen);
1103                 STADJUST(savelen, out);
1104                 ckfree(str);
1105                 str = NULL;
1106         }
1107         if (ostr) {
1108                 ckfree(ostr);
1109                 ostr = NULL;
1110         }
1111         here = saveheredoclist;
1112         if (here != NULL) {
1113                 while (here->next != NULL)
1114                         here = here->next;
1115                 here->next = heredoclist;
1116                 heredoclist = saveheredoclist;
1117         }
1118         handler = savehandler;
1119         INTON;
1120         if (quoted)
1121                 USTPUTC(CTLBACKQ | CTLQUOTE, out);
1122         else
1123                 USTPUTC(CTLBACKQ, out);
1124         return out;
1125 }
1126
1127
1128 /*
1129  * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
1130  * is not NULL, read a here document.  In the latter case, eofmark is the
1131  * word which marks the end of the document and striptabs is true if
1132  * leading tabs should be stripped from the document.  The argument firstc
1133  * is the first character of the input token or document.
1134  *
1135  * Because C does not have internal subroutines, I have simulated them
1136  * using goto's to implement the subroutine linkage.  The following macros
1137  * will run code that appears at the end of readtoken1.
1138  */
1139
1140 #define CHECKEND()      {goto checkend; checkend_return:;}
1141 #define PARSEREDIR()    {goto parseredir; parseredir_return:;}
1142 #define PARSESUB()      {goto parsesub; parsesub_return:;}
1143 #define PARSEARITH()    {goto parsearith; parsearith_return:;}
1144
1145 static int
1146 readtoken1(int firstc, char const *initialsyntax, char *eofmark, int striptabs)
1147 {
1148         int c = firstc;
1149         char * volatile out;
1150         int len;
1151         char line[EOFMARKLEN + 1];
1152         struct nodelist *bqlist;
1153         volatile int quotef;
1154         int newvarnest;
1155         int level;
1156         int synentry;
1157         struct tokenstate state_static[MAXNEST_STATIC];
1158         int maxnest = MAXNEST_STATIC;
1159         struct tokenstate *state = state_static;
1160
1161         startlinno = plinno;
1162         quotef = 0;
1163         bqlist = NULL;
1164         newvarnest = 0;
1165         level = 0;
1166         state[level].syntax = initialsyntax;
1167         state[level].parenlevel = 0;
1168         state[level].category = TSTATE_TOP;
1169
1170         STARTSTACKSTR(out);
1171         loop: { /* for each line, until end of word */
1172                 CHECKEND();     /* set c to PEOF if at end of here document */
1173                 for (;;) {      /* until end of line or end of word */
1174                         CHECKSTRSPACE(4, out);  /* permit 4 calls to USTPUTC */
1175
1176                         synentry = state[level].syntax[c];
1177
1178                         switch(synentry) {
1179                         case CNL:       /* '\n' */
1180                                 if (state[level].syntax == BASESYNTAX)
1181                                         goto endword;   /* exit outer loop */
1182                                 USTPUTC(c, out);
1183                                 plinno++;
1184                                 if (doprompt)
1185                                         setprompt(2);
1186                                 else
1187                                         setprompt(0);
1188                                 c = pgetc();
1189                                 goto loop;              /* continue outer loop */
1190                         case CWORD:
1191                                 USTPUTC(c, out);
1192                                 break;
1193                         case CCTL:
1194                                 if (eofmark == NULL || initialsyntax != SQSYNTAX)
1195                                         USTPUTC(CTLESC, out);
1196                                 USTPUTC(c, out);
1197                                 break;
1198                         case CBACK:     /* backslash */
1199                                 c = pgetc();
1200                                 if (c == PEOF) {
1201                                         USTPUTC('\\', out);
1202                                         pungetc();
1203                                 } else if (c == '\n') {
1204                                         plinno++;
1205                                         if (doprompt)
1206                                                 setprompt(2);
1207                                         else
1208                                                 setprompt(0);
1209                                 } else {
1210                                         if (state[level].syntax == DQSYNTAX &&
1211                                             c != '\\' && c != '`' && c != '$' &&
1212                                             (c != '"' || (eofmark != NULL &&
1213                                                 newvarnest == 0)) &&
1214                                             (c != '}' || state[level].category != TSTATE_VAR_OLD))
1215                                                 USTPUTC('\\', out);
1216                                         if ((eofmark == NULL ||
1217                                             newvarnest > 0) &&
1218                                             state[level].syntax == BASESYNTAX)
1219                                                 USTPUTC(CTLQUOTEMARK, out);
1220                                         if (SQSYNTAX[c] == CCTL)
1221                                                 USTPUTC(CTLESC, out);
1222                                         USTPUTC(c, out);
1223                                         if ((eofmark == NULL ||
1224                                             newvarnest > 0) &&
1225                                             state[level].syntax == BASESYNTAX &&
1226                                             state[level].category == TSTATE_VAR_OLD)
1227                                                 USTPUTC(CTLQUOTEEND, out);
1228                                         quotef++;
1229                                 }
1230                                 break;
1231                         case CSQUOTE:
1232                                 USTPUTC(CTLQUOTEMARK, out);
1233                                 state[level].syntax = SQSYNTAX;
1234                                 break;
1235                         case CDQUOTE:
1236                                 USTPUTC(CTLQUOTEMARK, out);
1237                                 state[level].syntax = DQSYNTAX;
1238                                 break;
1239                         case CENDQUOTE:
1240                                 if (eofmark != NULL && newvarnest == 0)
1241                                         USTPUTC(c, out);
1242                                 else {
1243                                         if (state[level].category == TSTATE_VAR_OLD)
1244                                                 USTPUTC(CTLQUOTEEND, out);
1245                                         state[level].syntax = BASESYNTAX;
1246                                         quotef++;
1247                                 }
1248                                 break;
1249                         case CVAR:      /* '$' */
1250                                 PARSESUB();             /* parse substitution */
1251                                 break;
1252                         case CENDVAR:   /* '}' */
1253                                 if (level > 0 &&
1254                                     ((state[level].category == TSTATE_VAR_OLD &&
1255                                       state[level].syntax ==
1256                                       state[level - 1].syntax) ||
1257                                     (state[level].category == TSTATE_VAR_NEW &&
1258                                      state[level].syntax == BASESYNTAX))) {
1259                                         if (state[level].category == TSTATE_VAR_NEW)
1260                                                 newvarnest--;
1261                                         level--;
1262                                         USTPUTC(CTLENDVAR, out);
1263                                 } else {
1264                                         USTPUTC(c, out);
1265                                 }
1266                                 break;
1267                         case CLP:       /* '(' in arithmetic */
1268                                 state[level].parenlevel++;
1269                                 USTPUTC(c, out);
1270                                 break;
1271                         case CRP:       /* ')' in arithmetic */
1272                                 if (state[level].parenlevel > 0) {
1273                                         USTPUTC(c, out);
1274                                         --state[level].parenlevel;
1275                                 } else {
1276                                         if (pgetc() == ')') {
1277                                                 if (level > 0 &&
1278                                                     state[level].category == TSTATE_ARITH) {
1279                                                         level--;
1280                                                         USTPUTC(CTLENDARI, out);
1281                                                 } else
1282                                                         USTPUTC(')', out);
1283                                         } else {
1284                                                 /*
1285                                                  * unbalanced parens
1286                                                  *  (don't 2nd guess - no error)
1287                                                  */
1288                                                 pungetc();
1289                                                 USTPUTC(')', out);
1290                                         }
1291                                 }
1292                                 break;
1293                         case CBQUOTE:   /* '`' */
1294                                 out = parsebackq(out, &bqlist, 1,
1295                                     state[level].syntax == DQSYNTAX &&
1296                                     (eofmark == NULL || newvarnest > 0),
1297                                     state[level].syntax == DQSYNTAX || state[level].syntax == ARISYNTAX);
1298                                 break;
1299                         case CEOF:
1300                                 goto endword;           /* exit outer loop */
1301                         case CIGN:
1302                                 break;
1303                         default:
1304                                 if (level == 0)
1305                                         goto endword;   /* exit outer loop */
1306                                 USTPUTC(c, out);
1307                         }
1308                         c = pgetc_macro();
1309                 }
1310         }
1311 endword:
1312         if (state[level].syntax == ARISYNTAX)
1313                 synerror("Missing '))'");
1314         if (state[level].syntax != BASESYNTAX && eofmark == NULL)
1315                 synerror("Unterminated quoted string");
1316         if (state[level].category == TSTATE_VAR_OLD ||
1317             state[level].category == TSTATE_VAR_NEW) {
1318                 startlinno = plinno;
1319                 synerror("Missing '}'");
1320         }
1321         if (state != state_static)
1322                 parser_temp_free_upto(state);
1323         USTPUTC('\0', out);
1324         len = out - stackblock();
1325         out = stackblock();
1326         if (eofmark == NULL) {
1327                 if ((c == '>' || c == '<')
1328                  && quotef == 0
1329                  && len <= 2
1330                  && (*out == '\0' || is_digit(*out))) {
1331                         PARSEREDIR();
1332                         return lasttoken = TREDIR;
1333                 } else {
1334                         pungetc();
1335                 }
1336         }
1337         quoteflag = quotef;
1338         backquotelist = bqlist;
1339         grabstackblock(len);
1340         wordtext = out;
1341         return lasttoken = TWORD;
1342 /* end of readtoken routine */
1343
1344
1345 /*
1346  * Check to see whether we are at the end of the here document.  When this
1347  * is called, c is set to the first character of the next input line.  If
1348  * we are at the end of the here document, this routine sets the c to PEOF.
1349  */
1350
1351 checkend: {
1352         if (eofmark) {
1353                 if (striptabs) {
1354                         while (c == '\t')
1355                                 c = pgetc();
1356                 }
1357                 if (c == *eofmark) {
1358                         if (pfgets(line, sizeof line) != NULL) {
1359                                 char *p, *q;
1360
1361                                 p = line;
1362                                 for (q = eofmark + 1 ; *q && *p == *q ; p++, q++);
1363                                 if (*p == '\n' && *q == '\0') {
1364                                         c = PEOF;
1365                                         plinno++;
1366                                         needprompt = doprompt;
1367                                 } else {
1368                                         pushstring(line, strlen(line), NULL);
1369                                 }
1370                         }
1371                 }
1372         }
1373         goto checkend_return;
1374 }
1375
1376
1377 /*
1378  * Parse a redirection operator.  The variable "out" points to a string
1379  * specifying the fd to be redirected.  The variable "c" contains the
1380  * first character of the redirection operator.
1381  */
1382
1383 parseredir: {
1384         char fd = *out;
1385         union node *np;
1386
1387         np = (union node *)stalloc(sizeof (struct nfile));
1388         if (c == '>') {
1389                 np->nfile.fd = 1;
1390                 c = pgetc();
1391                 if (c == '>')
1392                         np->type = NAPPEND;
1393                 else if (c == '&')
1394                         np->type = NTOFD;
1395                 else if (c == '|')
1396                         np->type = NCLOBBER;
1397                 else {
1398                         np->type = NTO;
1399                         pungetc();
1400                 }
1401         } else {        /* c == '<' */
1402                 np->nfile.fd = 0;
1403                 c = pgetc();
1404                 if (c == '<') {
1405                         if (sizeof (struct nfile) != sizeof (struct nhere)) {
1406                                 np = (union node *)stalloc(sizeof (struct nhere));
1407                                 np->nfile.fd = 0;
1408                         }
1409                         np->type = NHERE;
1410                         heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
1411                         heredoc->here = np;
1412                         if ((c = pgetc()) == '-') {
1413                                 heredoc->striptabs = 1;
1414                         } else {
1415                                 heredoc->striptabs = 0;
1416                                 pungetc();
1417                         }
1418                 } else if (c == '&')
1419                         np->type = NFROMFD;
1420                 else if (c == '>')
1421                         np->type = NFROMTO;
1422                 else {
1423                         np->type = NFROM;
1424                         pungetc();
1425                 }
1426         }
1427         if (fd != '\0')
1428                 np->nfile.fd = digit_val(fd);
1429         redirnode = np;
1430         goto parseredir_return;
1431 }
1432
1433
1434 /*
1435  * Parse a substitution.  At this point, we have read the dollar sign
1436  * and nothing else.
1437  */
1438
1439 parsesub: {
1440         char buf[10];
1441         int subtype;
1442         int typeloc;
1443         int flags;
1444         char *p;
1445         static const char types[] = "}-+?=";
1446         int bracketed_name = 0; /* used to handle ${[0-9]*} variables */
1447         int linno;
1448         int length;
1449
1450         c = pgetc();
1451         if (c != '(' && c != '{' && (is_eof(c) || !is_name(c)) &&
1452             !is_special(c)) {
1453                 USTPUTC('$', out);
1454                 pungetc();
1455         } else if (c == '(') {  /* $(command) or $((arith)) */
1456                 if (pgetc() == '(') {
1457                         PARSEARITH();
1458                 } else {
1459                         pungetc();
1460                         out = parsebackq(out, &bqlist, 0,
1461                             state[level].syntax == DQSYNTAX &&
1462                             (eofmark == NULL || newvarnest > 0),
1463                             state[level].syntax == DQSYNTAX ||
1464                             state[level].syntax == ARISYNTAX);
1465                 }
1466         } else {
1467                 USTPUTC(CTLVAR, out);
1468                 typeloc = out - stackblock();
1469                 USTPUTC(VSNORMAL, out);
1470                 subtype = VSNORMAL;
1471                 flags = 0;
1472                 if (c == '{') {
1473                         bracketed_name = 1;
1474                         c = pgetc();
1475                         if (c == '#') {
1476                                 if ((c = pgetc()) == '}')
1477                                         c = '#';
1478                                 else
1479                                         subtype = VSLENGTH;
1480                         }
1481                         else
1482                                 subtype = 0;
1483                 }
1484                 if (!is_eof(c) && is_name(c)) {
1485                         length = 0;
1486                         do {
1487                                 STPUTC(c, out);
1488                                 c = pgetc();
1489                                 length++;
1490                         } while (!is_eof(c) && is_in_name(c));
1491                         if (length == 6 &&
1492                             strncmp(out - length, "LINENO", length) == 0) {
1493                                 /* Replace the variable name with the
1494                                  * current line number. */
1495                                 linno = plinno;
1496                                 if (funclinno != 0)
1497                                         linno -= funclinno - 1;
1498                                 snprintf(buf, sizeof(buf), "%d", linno);
1499                                 STADJUST(-6, out);
1500                                 STPUTS(buf, out);
1501                                 flags |= VSLINENO;
1502                         }
1503                 } else if (is_digit(c)) {
1504                         if (bracketed_name) {
1505                                 do {
1506                                         STPUTC(c, out);
1507                                         c = pgetc();
1508                                 } while (is_digit(c));
1509                         } else {
1510                                 STPUTC(c, out);
1511                                 c = pgetc();
1512                         }
1513                 } else {
1514                         if (! is_special(c)) {
1515                                 subtype = VSERROR;
1516                                 if (c == '}')
1517                                         pungetc();
1518                                 else if (c == '\n' || c == PEOF)
1519                                         synerror("Unexpected end of line in substitution");
1520                                 else
1521                                         USTPUTC(c, out);
1522                         } else {
1523                                 USTPUTC(c, out);
1524                                 c = pgetc();
1525                         }
1526                 }
1527                 if (subtype == 0) {
1528                         switch (c) {
1529                         case ':':
1530                                 flags |= VSNUL;
1531                                 c = pgetc();
1532                                 /*FALLTHROUGH*/
1533                         default:
1534                                 p = strchr(types, c);
1535                                 if (p == NULL) {
1536                                         if (c == '\n' || c == PEOF)
1537                                                 synerror("Unexpected end of line in substitution");
1538                                         if (flags == VSNUL)
1539                                                 STPUTC(':', out);
1540                                         STPUTC(c, out);
1541                                         subtype = VSERROR;
1542                                 } else
1543                                         subtype = p - types + VSNORMAL;
1544                                 break;
1545                         case '%':
1546                         case '#':
1547                                 {
1548                                         int cc = c;
1549                                         subtype = c == '#' ? VSTRIMLEFT :
1550                                                              VSTRIMRIGHT;
1551                                         c = pgetc();
1552                                         if (c == cc)
1553                                                 subtype++;
1554                                         else
1555                                                 pungetc();
1556                                         break;
1557                                 }
1558                         }
1559                 } else if (subtype != VSERROR) {
1560                         pungetc();
1561                 }
1562                 STPUTC('=', out);
1563                 if (subtype != VSLENGTH && (state[level].syntax == DQSYNTAX ||
1564                     state[level].syntax == ARISYNTAX))
1565                         flags |= VSQUOTE;
1566                 *(stackblock() + typeloc) = subtype | flags;
1567                 if (subtype != VSNORMAL) {
1568                         if (level + 1 >= maxnest) {
1569                                 maxnest *= 2;
1570                                 if (state == state_static) {
1571                                         state = parser_temp_alloc(
1572                                             maxnest * sizeof(*state));
1573                                         memcpy(state, state_static,
1574                                             MAXNEST_STATIC * sizeof(*state));
1575                                 } else
1576                                         state = parser_temp_realloc(state,
1577                                             maxnest * sizeof(*state));
1578                         }
1579                         level++;
1580                         state[level].parenlevel = 0;
1581                         if (subtype == VSMINUS || subtype == VSPLUS ||
1582                             subtype == VSQUESTION || subtype == VSASSIGN) {
1583                                 /*
1584                                  * For operators that were in the Bourne shell,
1585                                  * inherit the double-quote state.
1586                                  */
1587                                 state[level].syntax = state[level - 1].syntax;
1588                                 state[level].category = TSTATE_VAR_OLD;
1589                         } else {
1590                                 /*
1591                                  * The other operators take a pattern,
1592                                  * so go to BASESYNTAX.
1593                                  * Also, ' and " are now special, even
1594                                  * in here documents.
1595                                  */
1596                                 state[level].syntax = BASESYNTAX;
1597                                 state[level].category = TSTATE_VAR_NEW;
1598                                 newvarnest++;
1599                         }
1600                 }
1601         }
1602         goto parsesub_return;
1603 }
1604
1605
1606 /*
1607  * Parse an arithmetic expansion (indicate start of one and set state)
1608  */
1609 parsearith: {
1610
1611         if (level + 1 >= maxnest) {
1612                 maxnest *= 2;
1613                 if (state == state_static) {
1614                         state = parser_temp_alloc(
1615                             maxnest * sizeof(*state));
1616                         memcpy(state, state_static,
1617                             MAXNEST_STATIC * sizeof(*state));
1618                 } else
1619                         state = parser_temp_realloc(state,
1620                             maxnest * sizeof(*state));
1621         }
1622         level++;
1623         state[level].syntax = ARISYNTAX;
1624         state[level].parenlevel = 0;
1625         state[level].category = TSTATE_ARITH;
1626         USTPUTC(CTLARI, out);
1627         if (state[level - 1].syntax == DQSYNTAX)
1628                 USTPUTC('"',out);
1629         else
1630                 USTPUTC(' ',out);
1631         goto parsearith_return;
1632 }
1633
1634 } /* end of readtoken */
1635
1636
1637
1638 #ifdef mkinit
1639 RESET {
1640         tokpushback = 0;
1641         checkkwd = 0;
1642 }
1643 #endif
1644
1645 /*
1646  * Returns true if the text contains nothing to expand (no dollar signs
1647  * or backquotes).
1648  */
1649
1650 static int
1651 noexpand(char *text)
1652 {
1653         char *p;
1654         char c;
1655
1656         p = text;
1657         while ((c = *p++) != '\0') {
1658                 if ( c == CTLQUOTEMARK)
1659                         continue;
1660                 if (c == CTLESC)
1661                         p++;
1662                 else if (BASESYNTAX[(int)c] == CCTL)
1663                         return 0;
1664         }
1665         return 1;
1666 }
1667
1668
1669 /*
1670  * Return true if the argument is a legal variable name (a letter or
1671  * underscore followed by zero or more letters, underscores, and digits).
1672  */
1673
1674 int
1675 goodname(const char *name)
1676 {
1677         const char *p;
1678
1679         p = name;
1680         if (! is_name(*p))
1681                 return 0;
1682         while (*++p) {
1683                 if (! is_in_name(*p))
1684                         return 0;
1685         }
1686         return 1;
1687 }
1688
1689
1690 /*
1691  * Called when an unexpected token is read during the parse.  The argument
1692  * is the token that is expected, or -1 if more than one type of token can
1693  * occur at this point.
1694  */
1695
1696 static void
1697 synexpect(int token)
1698 {
1699         char msg[64];
1700
1701         if (token >= 0) {
1702                 fmtstr(msg, 64, "%s unexpected (expecting %s)",
1703                         tokname[lasttoken], tokname[token]);
1704         } else {
1705                 fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
1706         }
1707         synerror(msg);
1708 }
1709
1710
1711 static void
1712 synerror(const char *msg)
1713 {
1714         if (commandname)
1715                 outfmt(out2, "%s: %d: ", commandname, startlinno);
1716         outfmt(out2, "Syntax error: %s\n", msg);
1717         error(NULL);
1718 }
1719
1720 static void
1721 setprompt(int which)
1722 {
1723         whichprompt = which;
1724
1725 #ifndef NO_HISTORY
1726         if (!el)
1727 #endif
1728         {
1729                 out2str(getprompt(NULL));
1730                 flushout(out2);
1731         }
1732 }
1733
1734 /*
1735  * called by editline -- any expansions to the prompt
1736  *    should be added here.
1737  */
1738 const char *
1739 getprompt(void *unused __unused)
1740 {
1741         static char ps[PROMPTLEN];
1742         const char *fmt;
1743         const char *pwd;
1744         int i, trim;
1745
1746         /*
1747          * Select prompt format.
1748          */
1749         switch (whichprompt) {
1750         case 0:
1751                 fmt = "";
1752                 break;
1753         case 1:
1754                 fmt = ps1val();
1755                 break;
1756         case 2:
1757                 fmt = ps2val();
1758                 break;
1759         default:
1760                 return "??";
1761         }
1762
1763         /*
1764          * Format prompt string.
1765          */
1766         for (i = 0; (i < 127) && (*fmt != '\0'); i++, fmt++)
1767                 if (*fmt == '\\')
1768                         switch (*++fmt) {
1769
1770                                 /*
1771                                  * Hostname.
1772                                  *
1773                                  * \h specifies just the local hostname,
1774                                  * \H specifies fully-qualified hostname.
1775                                  */
1776                         case 'h':
1777                         case 'H':
1778                                 ps[i] = '\0';
1779                                 gethostname(&ps[i], PROMPTLEN - i);
1780                                 /* Skip to end of hostname. */
1781                                 trim = (*fmt == 'h') ? '.' : '\0';
1782                                 while ((ps[i+1] != '\0') && (ps[i+1] != trim))
1783                                         i++;
1784                                 break;
1785
1786                                 /*
1787                                  * Working directory.
1788                                  *
1789                                  * \W specifies just the final component,
1790                                  * \w specifies the entire path.
1791                                  */
1792                         case 'W':
1793                         case 'w':
1794                                 pwd = lookupvar("PWD");
1795                                 if (pwd == NULL)
1796                                         pwd = "?";
1797                                 if (*fmt == 'W' &&
1798                                     *pwd == '/' && pwd[1] != '\0')
1799                                         strlcpy(&ps[i], strrchr(pwd, '/') + 1,
1800                                             PROMPTLEN - i);
1801                                 else
1802                                         strlcpy(&ps[i], pwd, PROMPTLEN - i);
1803                                 /* Skip to end of path. */
1804                                 while (ps[i + 1] != '\0')
1805                                         i++;
1806                                 break;
1807
1808                                 /*
1809                                  * Superuser status.
1810                                  *
1811                                  * '$' for normal users, '#' for root.
1812                                  */
1813                         case '$':
1814                                 ps[i] = (geteuid() != 0) ? '$' : '#';
1815                                 break;
1816
1817                                 /*
1818                                  * A literal \.
1819                                  */
1820                         case '\\':
1821                                 ps[i] = '\\';
1822                                 break;
1823
1824                                 /*
1825                                  * Emit unrecognized formats verbatim.
1826                                  */
1827                         default:
1828                                 ps[i++] = '\\';
1829                                 ps[i] = *fmt;
1830                                 break;
1831                         }
1832                 else
1833                         ps[i] = *fmt;
1834         ps[i] = '\0';
1835         return (ps);
1836 }