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: head/bin/sh/parser.c 245382 2013-01-13 19:26:33Z jilles $
  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 != NULL && n2->type == NPIPE) {
 243                                 n2->npipe.backgnd = 1;
 244                         } else if (n2 != NULL && 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 ? peektoken() == TEOF :
 289                             tokendlist[peektoken()]))
 290                                 return ntop;
 291                         break;
 292                 case TEOF:
 293                         if (heredoclist)
 294                                 parseheredoc();
 295                         else
 296                                 pungetc();              /* push back EOF on input */
 297                         return ntop;
 298                 default:
 299                         if (nlflag || erflag)
 300                                 synexpect(-1);
 301                         tokpushback++;
 302                         return ntop;
 303                 }
 304         }
 305 }
 306
 307
 308
 309 static union node *
 310 andor(void)
 311 {
 312         union node *n1, *n2, *n3;
 313         int t;
 314
 315         n1 = pipeline();
 316         for (;;) {
 317                 if ((t = readtoken()) == TAND) {
 318                         t = NAND;
 319                 } else if (t == TOR) {
 320                         t = NOR;
 321                 } else {
 322                         tokpushback++;
 323                         return n1;
 324                 }
 325                 n2 = pipeline();
 326                 n3 = (union node *)stalloc(sizeof (struct nbinary));
 327                 n3->type = t;
 328                 n3->nbinary.ch1 = n1;
 329                 n3->nbinary.ch2 = n2;
 330                 n1 = n3;
 331         }
 332 }
 333
 334
 335
 336 static union node *
 337 pipeline(void)
 338 {
 339         union node *n1, *n2, *pipenode;
 340         struct nodelist *lp, *prev;
 341         int negate, t;
 342
 343         negate = 0;
 344         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 345         TRACE(("pipeline: entered\n"));
 346         while (readtoken() == TNOT)
 347                 negate = !negate;
 348         tokpushback++;
 349         n1 = command();
 350         if (readtoken() == TPIPE) {
 351                 pipenode = (union node *)stalloc(sizeof (struct npipe));
 352                 pipenode->type = NPIPE;
 353                 pipenode->npipe.backgnd = 0;
 354                 lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 355                 pipenode->npipe.cmdlist = lp;
 356                 lp->n = n1;
 357                 do {
 358                         prev = lp;
 359                         lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 360                         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 361                         t = readtoken();
 362                         tokpushback++;
 363                         if (t == TNOT)
 364                                 lp->n = pipeline();
 365                         else
 366                                 lp->n = command();
 367                         prev->next = lp;
 368                 } while (readtoken() == TPIPE);
 369                 lp->next = NULL;
 370                 n1 = pipenode;
 371         }
 372         tokpushback++;
 373         if (negate) {
 374                 n2 = (union node *)stalloc(sizeof (struct nnot));
 375                 n2->type = NNOT;
 376                 n2->nnot.com = n1;
 377                 return n2;
 378         } else
 379                 return n1;
 380 }
 381
 382
 383
 384 static union node *
 385 command(void)
 386 {
 387         union node *n1, *n2;
 388         union node *ap, **app;
 389         union node *cp, **cpp;
 390         union node *redir, **rpp;
 391         int t;
 392         int is_subshell;
 393
 394         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 395         is_subshell = 0;
 396         redir = NULL;
 397         n1 = NULL;
 398         rpp = &redir;
 399
 400         /* Check for redirection which may precede command */
 401         while (readtoken() == TREDIR) {
 402                 *rpp = n2 = redirnode;
 403                 rpp = &n2->nfile.next;
 404                 parsefname();
 405         }
 406         tokpushback++;
 407
 408         switch (readtoken()) {
 409         case TIF:
 410                 n1 = (union node *)stalloc(sizeof (struct nif));
 411                 n1->type = NIF;
 412                 if ((n1->nif.test = list(0, 0)) == NULL)
 413                         synexpect(-1);
 414                 if (readtoken() != TTHEN)
 415                         synexpect(TTHEN);
 416                 n1->nif.ifpart = list(0, 0);
 417                 n2 = n1;
 418                 while (readtoken() == TELIF) {
 419                         n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
 420                         n2 = n2->nif.elsepart;
 421                         n2->type = NIF;
 422                         if ((n2->nif.test = list(0, 0)) == NULL)
 423                                 synexpect(-1);
 424                         if (readtoken() != TTHEN)
 425                                 synexpect(TTHEN);
 426                         n2->nif.ifpart = list(0, 0);
 427                 }
 428                 if (lasttoken == TELSE)
 429                         n2->nif.elsepart = list(0, 0);
 430                 else {
 431                         n2->nif.elsepart = NULL;
 432                         tokpushback++;
 433                 }
 434                 if (readtoken() != TFI)
 435                         synexpect(TFI);
 436                 checkkwd = CHKKWD | CHKALIAS;
 437                 break;
 438         case TWHILE:
 439         case TUNTIL: {
 440                 int got;
 441                 n1 = (union node *)stalloc(sizeof (struct nbinary));
 442                 n1->type = (lasttoken == TWHILE)? NWHILE : NUNTIL;
 443                 if ((n1->nbinary.ch1 = list(0, 0)) == NULL)
 444                         synexpect(-1);
 445                 if ((got=readtoken()) != TDO) {
 446 TRACE(("expecting DO got %s %s\n", tokname[got], got == TWORD ? wordtext : ""));
 447                         synexpect(TDO);
 448                 }
 449                 n1->nbinary.ch2 = list(0, 0);
 450                 if (readtoken() != TDONE)
 451                         synexpect(TDONE);
 452                 checkkwd = CHKKWD | CHKALIAS;
 453                 break;
 454         }
 455         case TFOR:
 456                 if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
 457                         synerror("Bad for loop variable");
 458                 n1 = (union node *)stalloc(sizeof (struct nfor));
 459                 n1->type = NFOR;
 460                 n1->nfor.var = wordtext;
 461                 while (readtoken() == TNL)
 462                         ;
 463                 if (lasttoken == TWORD && ! quoteflag && equal(wordtext, "in")) {
 464                         app = &ap;
 465                         while (readtoken() == TWORD) {
 466                                 n2 = (union node *)stalloc(sizeof (struct narg));
 467                                 n2->type = NARG;
 468                                 n2->narg.text = wordtext;
 469                                 n2->narg.backquote = backquotelist;
 470                                 *app = n2;
 471                                 app = &n2->narg.next;
 472                         }
 473                         *app = NULL;
 474                         n1->nfor.args = ap;
 475                         if (lasttoken != TNL && lasttoken != TSEMI)
 476                                 synexpect(-1);
 477                 } else {
 478                         static char argvars[5] = {
 479                                 CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'
 480                         };
 481                         n2 = (union node *)stalloc(sizeof (struct narg));
 482                         n2->type = NARG;
 483                         n2->narg.text = argvars;
 484                         n2->narg.backquote = NULL;
 485                         n2->narg.next = NULL;
 486                         n1->nfor.args = n2;
 487                         /*
 488                          * Newline or semicolon here is optional (but note
 489                          * that the original Bourne shell only allowed NL).
 490                          */
 491                         if (lasttoken != TNL && lasttoken != TSEMI)
 492                                 tokpushback++;
 493                 }
 494                 checkkwd = CHKNL | CHKKWD | CHKALIAS;
 495                 if ((t = readtoken()) == TDO)
 496                         t = TDONE;
 497                 else if (t == TBEGIN)
 498                         t = TEND;
 499                 else
 500                         synexpect(-1);
 501                 n1->nfor.body = list(0, 0);
 502                 if (readtoken() != t)
 503                         synexpect(t);
 504                 checkkwd = CHKKWD | CHKALIAS;
 505                 break;
 506         case TCASE:
 507                 n1 = (union node *)stalloc(sizeof (struct ncase));
 508                 n1->type = NCASE;
 509                 if (readtoken() != TWORD)
 510                         synexpect(TWORD);
 511                 n1->ncase.expr = n2 = (union node *)stalloc(sizeof (struct narg));
 512                 n2->type = NARG;
 513                 n2->narg.text = wordtext;
 514                 n2->narg.backquote = backquotelist;
 515                 n2->narg.next = NULL;
 516                 while (readtoken() == TNL);
 517                 if (lasttoken != TWORD || ! equal(wordtext, "in"))
 518                         synerror("expecting \"in\"");
 519                 cpp = &n1->ncase.cases;
 520                 checkkwd = CHKNL | CHKKWD, readtoken();
 521                 while (lasttoken != TESAC) {
 522                         *cpp = cp = (union node *)stalloc(sizeof (struct nclist));
 523                         cp->type = NCLIST;
 524                         app = &cp->nclist.pattern;
 525                         if (lasttoken == TLP)
 526                                 readtoken();
 527                         for (;;) {
 528                                 *app = ap = (union node *)stalloc(sizeof (struct narg));
 529                                 ap->type = NARG;
 530                                 ap->narg.text = wordtext;
 531                                 ap->narg.backquote = backquotelist;
 532                                 checkkwd = CHKNL | CHKKWD;
 533                                 if (readtoken() != TPIPE)
 534                                         break;
 535                                 app = &ap->narg.next;
 536                                 readtoken();
 537                         }
 538                         ap->narg.next = NULL;
 539                         if (lasttoken != TRP)
 540                                 synexpect(TRP);
 541                         cp->nclist.body = list(0, 0);
 542
 543                         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 544                         if ((t = readtoken()) != TESAC) {
 545                                 if (t == TENDCASE)
 546                                         ;
 547                                 else if (t == TFALLTHRU)
 548                                         cp->type = NCLISTFALLTHRU;
 549                                 else
 550                                         synexpect(TENDCASE);
 551                                 checkkwd = CHKNL | CHKKWD, readtoken();
 552                         }
 553                         cpp = &cp->nclist.next;
 554                 }
 555                 *cpp = NULL;
 556                 checkkwd = CHKKWD | CHKALIAS;
 557                 break;
 558         case TLP:
 559                 n1 = (union node *)stalloc(sizeof (struct nredir));
 560                 n1->type = NSUBSHELL;
 561                 n1->nredir.n = list(0, 0);
 562                 n1->nredir.redirect = NULL;
 563                 if (readtoken() != TRP)
 564                         synexpect(TRP);
 565                 checkkwd = CHKKWD | CHKALIAS;
 566                 is_subshell = 1;
 567                 break;
 568         case TBEGIN:
 569                 n1 = list(0, 0);
 570                 if (readtoken() != TEND)
 571                         synexpect(TEND);
 572                 checkkwd = CHKKWD | CHKALIAS;
 573                 break;
 574         /* Handle an empty command like other simple commands.  */
 575         case TBACKGND:
 576         case TSEMI:
 577         case TAND:
 578         case TOR:
 579                 /*
 580                  * An empty command before a ; doesn't make much sense, and
 581                  * should certainly be disallowed in the case of `if ;'.
 582                  */
 583                 if (!redir)
 584                         synexpect(-1);
 585         case TNL:
 586         case TEOF:
 587         case TWORD:
 588         case TRP:
 589                 tokpushback++;
 590                 n1 = simplecmd(rpp, redir);
 591                 return n1;
 592         default:
 593                 synexpect(-1);
 594         }
 595
 596         /* Now check for redirection which may follow command */
 597         while (readtoken() == TREDIR) {
 598                 *rpp = n2 = redirnode;
 599                 rpp = &n2->nfile.next;
 600                 parsefname();
 601         }
 602         tokpushback++;
 603         *rpp = NULL;
 604         if (redir) {
 605                 if (!is_subshell) {
 606                         n2 = (union node *)stalloc(sizeof (struct nredir));
 607                         n2->type = NREDIR;
 608                         n2->nredir.n = n1;
 609                         n1 = n2;
 610                 }
 611                 n1->nredir.redirect = redir;
 612         }
 613
 614         return n1;
 615 }
 616
 617
 618 static union node *
 619 simplecmd(union node **rpp, union node *redir)
 620 {
 621         union node *args, **app;
 622         union node **orig_rpp = rpp;
 623         union node *n = NULL;
 624         int special;
 625         int savecheckkwd;
 626
 627         /* If we don't have any redirections already, then we must reset */
 628         /* rpp to be the address of the local redir variable.  */
 629         if (redir == NULL)
 630                 rpp = &redir;
 631
 632         args = NULL;
 633         app = &args;
 634         /*
 635          * We save the incoming value, because we need this for shell
 636          * functions.  There can not be a redirect or an argument between
 637          * the function name and the open parenthesis.
 638          */
 639         orig_rpp = rpp;
 640
 641         savecheckkwd = CHKALIAS;
 642
 643         for (;;) {
 644                 checkkwd = savecheckkwd;
 645                 if (readtoken() == TWORD) {
 646                         n = (union node *)stalloc(sizeof (struct narg));
 647                         n->type = NARG;
 648                         n->narg.text = wordtext;
 649                         n->narg.backquote = backquotelist;
 650                         *app = n;
 651                         app = &n->narg.next;
 652                         if (savecheckkwd != 0 && !isassignment(wordtext))
 653                                 savecheckkwd = 0;
 654                 } else if (lasttoken == TREDIR) {
 655                         *rpp = n = redirnode;
 656                         rpp = &n->nfile.next;
 657                         parsefname();   /* read name of redirection file */
 658                 } else if (lasttoken == TLP && app == &args->narg.next
 659                                             && rpp == orig_rpp) {
 660                         /* We have a function */
 661                         if (readtoken() != TRP)
 662                                 synexpect(TRP);
 663                         funclinno = plinno;
 664                         /*
 665                          * - Require plain text.
 666                          * - Functions with '/' cannot be called.
 667                          * - Reject name=().
 668                          * - Reject ksh extended glob patterns.
 669                          */
 670                         if (!noexpand(n->narg.text) || quoteflag ||
 671                             strchr(n->narg.text, '/') ||
 672                             strchr("!%*+-=?@}~",
 673                                 n->narg.text[strlen(n->narg.text) - 1]))
 674                                 synerror("Bad function name");
 675                         rmescapes(n->narg.text);
 676                         if (find_builtin(n->narg.text, &special) >= 0 &&
 677                             special)
 678                                 synerror("Cannot override a special builtin with a function");
 679                         n->type = NDEFUN;
 680                         n->narg.next = command();
 681                         funclinno = 0;
 682                         return n;
 683                 } else {
 684                         tokpushback++;
 685                         break;
 686                 }
 687         }
 688         *app = NULL;
 689         *rpp = NULL;
 690         n = (union node *)stalloc(sizeof (struct ncmd));
 691         n->type = NCMD;
 692         n->ncmd.args = args;
 693         n->ncmd.redirect = redir;
 694         return n;
 695 }
 696
 697 static union node *
 698 makename(void)
 699 {
 700         union node *n;
 701
 702         n = (union node *)stalloc(sizeof (struct narg));
 703         n->type = NARG;
 704         n->narg.next = NULL;
 705         n->narg.text = wordtext;
 706         n->narg.backquote = backquotelist;
 707         return n;
 708 }
 709
 710 void
 711 fixredir(union node *n, const char *text, int err)
 712 {
 713         TRACE(("Fix redir %s %d\n", text, err));
 714         if (!err)
 715                 n->ndup.vname = NULL;
 716
 717         if (is_digit(text[0]) && text[1] == '\0')
 718                 n->ndup.dupfd = digit_val(text[0]);
 719         else if (text[0] == '-' && text[1] == '\0')
 720                 n->ndup.dupfd = -1;
 721         else {
 722
 723                 if (err)
 724                         synerror("Bad fd number");
 725                 else
 726                         n->ndup.vname = makename();
 727         }
 728 }
 729
 730
 731 static void
 732 parsefname(void)
 733 {
 734         union node *n = redirnode;
 735
 736         if (readtoken() != TWORD)
 737                 synexpect(-1);
 738         if (n->type == NHERE) {
 739                 struct heredoc *here = heredoc;
 740                 struct heredoc *p;
 741                 int i;
 742
 743                 if (quoteflag == 0)
 744                         n->type = NXHERE;
 745                 TRACE(("Here document %d\n", n->type));
 746                 if (here->striptabs) {
 747                         while (*wordtext == '\t')
 748                                 wordtext++;
 749                 }
 750                 if (! noexpand(wordtext) || (i = strlen(wordtext)) == 0 || i > EOFMARKLEN)
 751                         synerror("Illegal eof marker for << redirection");
 752                 rmescapes(wordtext);
 753                 here->eofmark = wordtext;
 754                 here->next = NULL;
 755                 if (heredoclist == NULL)
 756                         heredoclist = here;
 757                 else {
 758                         for (p = heredoclist ; p->next ; p = p->next);
 759                         p->next = here;
 760                 }
 761         } else if (n->type == NTOFD || n->type == NFROMFD) {
 762                 fixredir(n, wordtext, 0);
 763         } else {
 764                 n->nfile.fname = makename();
 765         }
 766 }
 767
 768
 769 /*
 770  * Input any here documents.
 771  */
 772
 773 static void
 774 parseheredoc(void)
 775 {
 776         struct heredoc *here;
 777         union node *n;
 778
 779         while (heredoclist) {
 780                 here = heredoclist;
 781                 heredoclist = here->next;
 782                 if (needprompt) {
 783                         setprompt(2);
 784                         needprompt = 0;
 785                 }
 786                 readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
 787                                 here->eofmark, here->striptabs);
 788                 n = (union node *)stalloc(sizeof (struct narg));
 789                 n->narg.type = NARG;
 790                 n->narg.next = NULL;
 791                 n->narg.text = wordtext;
 792                 n->narg.backquote = backquotelist;
 793                 here->here->nhere.doc = n;
 794         }
 795 }
 796
 797 static int
 798 peektoken(void)
 799 {
 800         int t;
 801
 802         t = readtoken();
 803         tokpushback++;
 804         return (t);
 805 }
 806
 807 static int
 808 readtoken(void)
 809 {
 810         int t;
 811         struct alias *ap;
 812 #ifdef DEBUG
 813         int alreadyseen = tokpushback;
 814 #endif
 815
 816         top:
 817         t = xxreadtoken();
 818
 819         /*
 820          * eat newlines
 821          */
 822         if (checkkwd & CHKNL) {
 823                 while (t == TNL) {
 824                         parseheredoc();
 825                         t = xxreadtoken();
 826                 }
 827         }
 828
 829         /*
 830          * check for keywords and aliases
 831          */
 832         if (t == TWORD && !quoteflag)
 833         {
 834                 const char * const *pp;
 835
 836                 if (checkkwd & CHKKWD)
 837                         for (pp = parsekwd; *pp; pp++) {
 838                                 if (**pp == *wordtext && equal(*pp, wordtext))
 839                                 {
 840                                         lasttoken = t = pp - parsekwd + KWDOFFSET;
 841                                         TRACE(("keyword %s recognized\n", tokname[t]));
 842                                         goto out;
 843                                 }
 844                         }
 845                 if (checkkwd & CHKALIAS &&
 846                     (ap = lookupalias(wordtext, 1)) != NULL) {
 847                         pushstring(ap->val, strlen(ap->val), ap);
 848                         goto top;
 849                 }
 850         }
 851 out:
 852         if (t != TNOT)
 853                 checkkwd = 0;
 854
 855 #ifdef DEBUG
 856         if (!alreadyseen)
 857             TRACE(("token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 858         else
 859             TRACE(("reread token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 860 #endif
 861         return (t);
 862 }
 863
 864
 865 /*
 866  * Read the next input token.
 867  * If the token is a word, we set backquotelist to the list of cmds in
 868  *      backquotes.  We set quoteflag to true if any part of the word was
 869  *      quoted.
 870  * If the token is TREDIR, then we set redirnode to a structure containing
 871  *      the redirection.
 872  * In all cases, the variable startlinno is set to the number of the line
 873  *      on which the token starts.
 874  *
 875  * [Change comment:  here documents and internal procedures]
 876  * [Readtoken shouldn't have any arguments.  Perhaps we should make the
 877  *  word parsing code into a separate routine.  In this case, readtoken
 878  *  doesn't need to have any internal procedures, but parseword does.
 879  *  We could also make parseoperator in essence the main routine, and
 880  *  have parseword (readtoken1?) handle both words and redirection.]
 881  */
 882
 883 #define RETURN(token)   return lasttoken = token
 884
 885 static int
 886 xxreadtoken(void)
 887 {
 888         int c;
 889
 890         if (tokpushback) {
 891                 tokpushback = 0;
 892                 return lasttoken;
 893         }
 894         if (needprompt) {
 895                 setprompt(2);
 896                 needprompt = 0;
 897         }
 898         startlinno = plinno;
 899         for (;;) {      /* until token or start of word found */
 900                 c = pgetc_macro();
 901                 switch (c) {
 902                 case ' ': case '\t':
 903                         continue;
 904                 case '#':
 905                         while ((c = pgetc()) != '\n' && c != PEOF);
 906                         pungetc();
 907                         continue;
 908                 case '\\':
 909                         if (pgetc() == '\n') {
 910                                 startlinno = ++plinno;
 911                                 if (doprompt)
 912                                         setprompt(2);
 913                                 else
 914                                         setprompt(0);
 915                                 continue;
 916                         }
 917                         pungetc();
 918                         goto breakloop;
 919                 case '\n':
 920                         plinno++;
 921                         needprompt = doprompt;
 922                         RETURN(TNL);
 923                 case PEOF:
 924                         RETURN(TEOF);
 925                 case '&':
 926                         if (pgetc() == '&')
 927                                 RETURN(TAND);
 928                         pungetc();
 929                         RETURN(TBACKGND);
 930                 case '|':
 931                         if (pgetc() == '|')
 932                                 RETURN(TOR);
 933                         pungetc();
 934                         RETURN(TPIPE);
 935                 case ';':
 936                         c = pgetc();
 937                         if (c == ';')
 938                                 RETURN(TENDCASE);
 939                         else if (c == '&')
 940                                 RETURN(TFALLTHRU);
 941                         pungetc();
 942                         RETURN(TSEMI);
 943                 case '(':
 944                         RETURN(TLP);
 945                 case ')':
 946                         RETURN(TRP);
 947                 default:
 948                         goto breakloop;
 949                 }
 950         }
 951 breakloop:
 952         return readtoken1(c, BASESYNTAX, NULL, 0);
 953 #undef RETURN
 954 }
 955
 956
 957 #define MAXNEST_STATIC 8
 958 struct tokenstate
 959 {
 960         const char *syntax; /* *SYNTAX */
 961         int parenlevel; /* levels of parentheses in arithmetic */
 962         enum tokenstate_category
 963         {
 964                 TSTATE_TOP,
 965                 TSTATE_VAR_OLD, /* ${var+-=?}, inherits dquotes */
 966                 TSTATE_VAR_NEW, /* other ${var...}, own dquote state */
 967                 TSTATE_ARITH
 968         } category;
 969 };
 970
 971
 972 /*
 973  * Called to parse command substitutions.
 974  */
 975
 976 static char *
 977 parsebackq(char *out, struct nodelist **pbqlist,
 978     int oldstyle, int dblquote, int quoted)
 979 {
 980         struct nodelist **nlpp;
 981         union node *n;
 982         char *volatile str;
 983         struct jmploc jmploc;
 984         struct jmploc *const savehandler = handler;
 985         int savelen;
 986         int saveprompt;
 987         const int bq_startlinno = plinno;
 988         char *volatile ostr = NULL;
 989         struct parsefile *const savetopfile = getcurrentfile();
 990         struct heredoc *const saveheredoclist = heredoclist;
 991         struct heredoc *here;
 992
 993         str = NULL;
 994         if (setjmp(jmploc.loc)) {
 995                 popfilesupto(savetopfile);
 996                 if (str)
 997                         ckfree(str);
 998                 if (ostr)
 999                         ckfree(ostr);
1000                 heredoclist = saveheredoclist;
1001                 handler = savehandler;
1002                 if (exception == EXERROR) {
1003                         startlinno = bq_startlinno;
1004                         synerror("Error in command substitution");
1005                 }
1006                 longjmp(handler->loc, 1);
1007         }
1008         INTOFF;
1009         savelen = out - stackblock();
1010         if (savelen > 0) {
1011                 str = ckmalloc(savelen);
1012                 memcpy(str, stackblock(), savelen);
1013         }
1014         handler = &jmploc;
1015         heredoclist = NULL;
1016         INTON;
1017         if (oldstyle) {
1018                 /*
1019                  * We must read until the closing backquote, giving special
1020                  * treatment to some slashes, and then push the string and
1021                  * reread it as input, interpreting it normally.
1022                  */
1023                 char *oout;
1024                 int c, olen;
1025
1026                 STARTSTACKSTR(oout);
1027                 for (;;) {
1028                         if (needprompt) {
1029                                 setprompt(2);
1030                                 needprompt = 0;
1031                         }
1032                         CHECKSTRSPACE(2, oout);
1033                         switch (c = pgetc()) {
1034                         case '`':
1035                                 goto done;
1036
1037                         case '\\':
1038                                 if ((c = pgetc()) == '\n') {
1039                                         plinno++;
1040                                         if (doprompt)
1041                                                 setprompt(2);
1042                                         else
1043                                                 setprompt(0);
1044                                         /*
1045                                          * If eating a newline, avoid putting
1046                                          * the newline into the new character
1047                                          * stream (via the USTPUTC after the
1048                                          * switch).
1049                                          */
1050                                         continue;
1051                                 }
1052                                 if (c != '\\' && c != '`' && c != '$'
1053                                     && (!dblquote || c != '"'))
1054                                         USTPUTC('\\', oout);
1055                                 break;
1056
1057                         case '\n':
1058                                 plinno++;
1059                                 needprompt = doprompt;
1060                                 break;
1061
1062                         case PEOF:
1063                                 startlinno = plinno;
1064                                 synerror("EOF in backquote substitution");
1065                                 break;
1066
1067                         default:
1068                                 break;
1069                         }
1070                         USTPUTC(c, oout);
1071                 }
1072 done:
1073                 USTPUTC('\0', oout);
1074                 olen = oout - stackblock();
1075                 INTOFF;
1076                 ostr = ckmalloc(olen);
1077                 memcpy(ostr, stackblock(), olen);
1078                 setinputstring(ostr, 1);
1079                 INTON;
1080         }
1081         nlpp = pbqlist;
1082         while (*nlpp)
1083                 nlpp = &(*nlpp)->next;
1084         *nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
1085         (*nlpp)->next = NULL;
1086
1087         if (oldstyle) {
1088                 saveprompt = doprompt;
1089                 doprompt = 0;
1090         }
1091
1092         n = list(0, oldstyle);
1093
1094         if (oldstyle)
1095                 doprompt = saveprompt;
1096         else {
1097                 if (readtoken() != TRP)
1098                         synexpect(TRP);
1099         }
1100
1101         (*nlpp)->n = n;
1102         if (oldstyle) {
1103                 /*
1104                  * Start reading from old file again, ignoring any pushed back
1105                  * tokens left from the backquote parsing
1106                  */
1107                 popfile();
1108                 tokpushback = 0;
1109         }
1110         STARTSTACKSTR(out);
1111         CHECKSTRSPACE(savelen + 1, out);
1112         INTOFF;
1113         if (str) {
1114                 memcpy(out, str, savelen);
1115                 STADJUST(savelen, out);
1116                 ckfree(str);
1117                 str = NULL;
1118         }
1119         if (ostr) {
1120                 ckfree(ostr);
1121                 ostr = NULL;
1122         }
1123         here = saveheredoclist;
1124         if (here != NULL) {
1125                 while (here->next != NULL)
1126                         here = here->next;
1127                 here->next = heredoclist;
1128                 heredoclist = saveheredoclist;
1129         }
1130         handler = savehandler;
1131         INTON;
1132         if (quoted)
1133                 USTPUTC(CTLBACKQ | CTLQUOTE, out);
1134         else
1135                 USTPUTC(CTLBACKQ, out);
1136         return out;
1137 }
1138
1139
1140 /*
1141  * Called to parse a backslash escape sequence inside $'...'.
1142  * The backslash has already been read.
1143  */
1144 static char *
1145 readcstyleesc(char *out)
1146 {
1147         int c, v, i, n;
1148
1149         c = pgetc();
1150         switch (c) {
1151         case '\0':
1152                 synerror("Unterminated quoted string");
1153         case '\n':
1154                 plinno++;
1155                 if (doprompt)
1156                         setprompt(2);
1157                 else
1158                         setprompt(0);
1159                 return out;
1160         case '\\':
1161         case '\'':
1162         case '"':
1163                 v = c;
1164                 break;
1165         case 'a': v = '\a'; break;
1166         case 'b': v = '\b'; break;
1167         case 'e': v = '\033'; break;
1168         case 'f': v = '\f'; break;
1169         case 'n': v = '\n'; break;
1170         case 'r': v = '\r'; break;
1171         case 't': v = '\t'; break;
1172         case 'v': v = '\v'; break;
1173         case 'x':
1174                   v = 0;
1175                   for (;;) {
1176                           c = pgetc();
1177                           if (c >= '0' && c <= '9')
1178                                   v = (v << 4) + c - '0';
1179                           else if (c >= 'A' && c <= 'F')
1180                                   v = (v << 4) + c - 'A' + 10;
1181                           else if (c >= 'a' && c <= 'f')
1182                                   v = (v << 4) + c - 'a' + 10;
1183                           else
1184                                   break;
1185                   }
1186                   pungetc();
1187                   break;
1188         case '0': case '1': case '2': case '3':
1189         case '4': case '5': case '6': case '7':
1190                   v = c - '0';
1191                   c = pgetc();
1192                   if (c >= '0' && c <= '7') {
1193                           v <<= 3;
1194                           v += c - '0';
1195                           c = pgetc();
1196                           if (c >= '0' && c <= '7') {
1197                                   v <<= 3;
1198                                   v += c - '0';
1199                           } else
1200                                   pungetc();
1201                   } else
1202                           pungetc();
1203                   break;
1204         case 'c':
1205                   c = pgetc();
1206                   if (c < 0x3f || c > 0x7a || c == 0x60)
1207                           synerror("Bad escape sequence");
1208                   if (c == '\\' && pgetc() != '\\')
1209                           synerror("Bad escape sequence");
1210                   if (c == '?')
1211                           v = 127;
1212                   else
1213                           v = c & 0x1f;
1214                   break;
1215         case 'u':
1216         case 'U':
1217                   n = c == 'U' ? 8 : 4;
1218                   v = 0;
1219                   for (i = 0; i < n; i++) {
1220                           c = pgetc();
1221                           if (c >= '0' && c <= '9')
1222                                   v = (v << 4) + c - '0';
1223                           else if (c >= 'A' && c <= 'F')
1224                                   v = (v << 4) + c - 'A' + 10;
1225                           else if (c >= 'a' && c <= 'f')
1226                                   v = (v << 4) + c - 'a' + 10;
1227                           else
1228                                   synerror("Bad escape sequence");
1229                   }
1230                   if (v == 0 || (v >= 0xd800 && v <= 0xdfff))
1231                           synerror("Bad escape sequence");
1232                   /* We really need iconv here. */
1233                   if (initial_localeisutf8 && v > 127) {
1234                           CHECKSTRSPACE(4, out);
1235                           /*
1236                            * We cannot use wctomb() as the locale may have
1237                            * changed.
1238                            */
1239                           if (v <= 0x7ff) {
1240                                   USTPUTC(0xc0 | v >> 6, out);
1241                                   USTPUTC(0x80 | (v & 0x3f), out);
1242                                   return out;
1243                           } else if (v <= 0xffff) {
1244                                   USTPUTC(0xe0 | v >> 12, out);
1245                                   USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
1246                                   USTPUTC(0x80 | (v & 0x3f), out);
1247                                   return out;
1248                           } else if (v <= 0x10ffff) {
1249                                   USTPUTC(0xf0 | v >> 18, out);
1250                                   USTPUTC(0x80 | ((v >> 12) & 0x3f), out);
1251                                   USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
1252                                   USTPUTC(0x80 | (v & 0x3f), out);
1253                                   return out;
1254                           }
1255                   }
1256                   if (v > 127)
1257                           v = '?';
1258                   break;
1259         default:
1260                   synerror("Bad escape sequence");
1261         }
1262         v = (char)v;
1263         /*
1264          * We can't handle NUL bytes.
1265          * POSIX says we should skip till the closing quote.
1266          */
1267         if (v == '\0') {
1268                 while ((c = pgetc()) != '\'') {
1269                         if (c == '\\')
1270                                 c = pgetc();
1271                         if (c == PEOF)
1272                                 synerror("Unterminated quoted string");
1273                 }
1274                 pungetc();
1275                 return out;
1276         }
1277         if (SQSYNTAX[v] == CCTL)
1278                 USTPUTC(CTLESC, out);
1279         USTPUTC(v, out);
1280         return out;
1281 }
1282
1283
1284 /*
1285  * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
1286  * is not NULL, read a here document.  In the latter case, eofmark is the
1287  * word which marks the end of the document and striptabs is true if
1288  * leading tabs should be stripped from the document.  The argument firstc
1289  * is the first character of the input token or document.
1290  *
1291  * Because C does not have internal subroutines, I have simulated them
1292  * using goto's to implement the subroutine linkage.  The following macros
1293  * will run code that appears at the end of readtoken1.
1294  */
1295
1296 #define CHECKEND()      {goto checkend; checkend_return:;}
1297 #define PARSEREDIR()    {goto parseredir; parseredir_return:;}
1298 #define PARSESUB()      {goto parsesub; parsesub_return:;}
1299 #define PARSEARITH()    {goto parsearith; parsearith_return:;}
1300
1301 static int
1302 readtoken1(int firstc, char const *initialsyntax, char *eofmark, int striptabs)
1303 {
1304         int c = firstc;
1305         char * volatile out;
1306         int len;
1307         char line[EOFMARKLEN + 1];
1308         struct nodelist *bqlist;
1309         volatile int quotef;
1310         int newvarnest;
1311         int level;
1312         int synentry;
1313         struct tokenstate state_static[MAXNEST_STATIC];
1314         int maxnest = MAXNEST_STATIC;
1315         struct tokenstate *state = state_static;
1316         int sqiscstyle = 0;
1317
1318         startlinno = plinno;
1319         quotef = 0;
1320         bqlist = NULL;
1321         newvarnest = 0;
1322         level = 0;
1323         state[level].syntax = initialsyntax;
1324         state[level].parenlevel = 0;
1325         state[level].category = TSTATE_TOP;
1326
1327         STARTSTACKSTR(out);
1328         loop: { /* for each line, until end of word */
1329                 CHECKEND();     /* set c to PEOF if at end of here document */
1330                 for (;;) {      /* until end of line or end of word */
1331                         CHECKSTRSPACE(4, out);  /* permit 4 calls to USTPUTC */
1332
1333                         synentry = state[level].syntax[c];
1334
1335                         switch(synentry) {
1336                         case CNL:       /* '\n' */
1337                                 if (state[level].syntax == BASESYNTAX)
1338                                         goto endword;   /* exit outer loop */
1339                                 USTPUTC(c, out);
1340                                 plinno++;
1341                                 if (doprompt)
1342                                         setprompt(2);
1343                                 else
1344                                         setprompt(0);
1345                                 c = pgetc();
1346                                 goto loop;              /* continue outer loop */
1347                         case CSBACK:
1348                                 if (sqiscstyle) {
1349                                         out = readcstyleesc(out);
1350                                         break;
1351                                 }
1352                                 /* FALLTHROUGH */
1353                         case CWORD:
1354                                 USTPUTC(c, out);
1355                                 break;
1356                         case CCTL:
1357                                 if (eofmark == NULL || initialsyntax != SQSYNTAX)
1358                                         USTPUTC(CTLESC, out);
1359                                 USTPUTC(c, out);
1360                                 break;
1361                         case CBACK:     /* backslash */
1362                                 c = pgetc();
1363                                 if (c == PEOF) {
1364                                         USTPUTC('\\', out);
1365                                         pungetc();
1366                                 } else if (c == '\n') {
1367                                         plinno++;
1368                                         if (doprompt)
1369                                                 setprompt(2);
1370                                         else
1371                                                 setprompt(0);
1372                                 } else {
1373                                         if (state[level].syntax == DQSYNTAX &&
1374                                             c != '\\' && c != '`' && c != '$' &&
1375                                             (c != '"' || (eofmark != NULL &&
1376                                                 newvarnest == 0)) &&
1377                                             (c != '}' || state[level].category != TSTATE_VAR_OLD))
1378                                                 USTPUTC('\\', out);
1379                                         if ((eofmark == NULL ||
1380                                             newvarnest > 0) &&
1381                                             state[level].syntax == BASESYNTAX)
1382                                                 USTPUTC(CTLQUOTEMARK, out);
1383                                         if (SQSYNTAX[c] == CCTL)
1384                                                 USTPUTC(CTLESC, out);
1385                                         USTPUTC(c, out);
1386                                         if ((eofmark == NULL ||
1387                                             newvarnest > 0) &&
1388                                             state[level].syntax == BASESYNTAX &&
1389                                             state[level].category == TSTATE_VAR_OLD)
1390                                                 USTPUTC(CTLQUOTEEND, out);
1391                                         quotef++;
1392                                 }
1393                                 break;
1394                         case CSQUOTE:
1395                                 USTPUTC(CTLQUOTEMARK, out);
1396                                 state[level].syntax = SQSYNTAX;
1397                                 sqiscstyle = 0;
1398                                 break;
1399                         case CDQUOTE:
1400                                 USTPUTC(CTLQUOTEMARK, out);
1401                                 state[level].syntax = DQSYNTAX;
1402                                 break;
1403                         case CENDQUOTE:
1404                                 if (eofmark != NULL && newvarnest == 0)
1405                                         USTPUTC(c, out);
1406                                 else {
1407                                         if (state[level].category == TSTATE_VAR_OLD)
1408                                                 USTPUTC(CTLQUOTEEND, out);
1409                                         state[level].syntax = BASESYNTAX;
1410                                         quotef++;
1411                                 }
1412                                 break;
1413                         case CVAR:      /* '$' */
1414                                 PARSESUB();             /* parse substitution */
1415                                 break;
1416                         case CENDVAR:   /* '}' */
1417                                 if (level > 0 &&
1418                                     ((state[level].category == TSTATE_VAR_OLD &&
1419                                       state[level].syntax ==
1420                                       state[level - 1].syntax) ||
1421                                     (state[level].category == TSTATE_VAR_NEW &&
1422                                      state[level].syntax == BASESYNTAX))) {
1423                                         if (state[level].category == TSTATE_VAR_NEW)
1424                                                 newvarnest--;
1425                                         level--;
1426                                         USTPUTC(CTLENDVAR, out);
1427                                 } else {
1428                                         USTPUTC(c, out);
1429                                 }
1430                                 break;
1431                         case CLP:       /* '(' in arithmetic */
1432                                 state[level].parenlevel++;
1433                                 USTPUTC(c, out);
1434                                 break;
1435                         case CRP:       /* ')' in arithmetic */
1436                                 if (state[level].parenlevel > 0) {
1437                                         USTPUTC(c, out);
1438                                         --state[level].parenlevel;
1439                                 } else {
1440                                         if (pgetc() == ')') {
1441                                                 if (level > 0 &&
1442                                                     state[level].category == TSTATE_ARITH) {
1443                                                         level--;
1444                                                         USTPUTC(CTLENDARI, out);
1445                                                 } else
1446                                                         USTPUTC(')', out);
1447                                         } else {
1448                                                 /*
1449                                                  * unbalanced parens
1450                                                  *  (don't 2nd guess - no error)
1451                                                  */
1452                                                 pungetc();
1453                                                 USTPUTC(')', out);
1454                                         }
1455                                 }
1456                                 break;
1457                         case CBQUOTE:   /* '`' */
1458                                 out = parsebackq(out, &bqlist, 1,
1459                                     state[level].syntax == DQSYNTAX &&
1460                                     (eofmark == NULL || newvarnest > 0),
1461                                     state[level].syntax == DQSYNTAX || state[level].syntax == ARISYNTAX);
1462                                 break;
1463                         case CEOF:
1464                                 goto endword;           /* exit outer loop */
1465                         case CIGN:
1466                                 break;
1467                         default:
1468                                 if (level == 0)
1469                                         goto endword;   /* exit outer loop */
1470                                 USTPUTC(c, out);
1471                         }
1472                         c = pgetc_macro();
1473                 }
1474         }
1475 endword:
1476         if (state[level].syntax == ARISYNTAX)
1477                 synerror("Missing '))'");
1478         if (state[level].syntax != BASESYNTAX && eofmark == NULL)
1479                 synerror("Unterminated quoted string");
1480         if (state[level].category == TSTATE_VAR_OLD ||
1481             state[level].category == TSTATE_VAR_NEW) {
1482                 startlinno = plinno;
1483                 synerror("Missing '}'");
1484         }
1485         if (state != state_static)
1486                 parser_temp_free_upto(state);
1487         USTPUTC('\0', out);
1488         len = out - stackblock();
1489         out = stackblock();
1490         if (eofmark == NULL) {
1491                 if ((c == '>' || c == '<')
1492                  && quotef == 0
1493                  && len <= 2
1494                  && (*out == '\0' || is_digit(*out))) {
1495                         PARSEREDIR();
1496                         return lasttoken = TREDIR;
1497                 } else {
1498                         pungetc();
1499                 }
1500         }
1501         quoteflag = quotef;
1502         backquotelist = bqlist;
1503         grabstackblock(len);
1504         wordtext = out;
1505         return lasttoken = TWORD;
1506 /* end of readtoken routine */
1507
1508
1509 /*
1510  * Check to see whether we are at the end of the here document.  When this
1511  * is called, c is set to the first character of the next input line.  If
1512  * we are at the end of the here document, this routine sets the c to PEOF.
1513  */
1514
1515 checkend: {
1516         if (eofmark) {
1517                 if (striptabs) {
1518                         while (c == '\t')
1519                                 c = pgetc();
1520                 }
1521                 if (c == *eofmark) {
1522                         if (pfgets(line, sizeof line) != NULL) {
1523                                 char *p, *q;
1524
1525                                 p = line;
1526                                 for (q = eofmark + 1 ; *q && *p == *q ; p++, q++);
1527                                 if ((*p == '\0' || *p == '\n') && *q == '\0') {
1528                                         c = PEOF;
1529                                         if (*p == '\n') {
1530                                                 plinno++;
1531                                                 needprompt = doprompt;
1532                                         }
1533                                 } else {
1534                                         pushstring(line, strlen(line), NULL);
1535                                 }
1536                         }
1537                 }
1538         }
1539         goto checkend_return;
1540 }
1541
1542
1543 /*
1544  * Parse a redirection operator.  The variable "out" points to a string
1545  * specifying the fd to be redirected.  The variable "c" contains the
1546  * first character of the redirection operator.
1547  */
1548
1549 parseredir: {
1550         char fd = *out;
1551         union node *np;
1552
1553         np = (union node *)stalloc(sizeof (struct nfile));
1554         if (c == '>') {
1555                 np->nfile.fd = 1;
1556                 c = pgetc();
1557                 if (c == '>')
1558                         np->type = NAPPEND;
1559                 else if (c == '&')
1560                         np->type = NTOFD;
1561                 else if (c == '|')
1562                         np->type = NCLOBBER;
1563                 else {
1564                         np->type = NTO;
1565                         pungetc();
1566                 }
1567         } else {        /* c == '<' */
1568                 np->nfile.fd = 0;
1569                 c = pgetc();
1570                 if (c == '<') {
1571                         if (sizeof (struct nfile) != sizeof (struct nhere)) {
1572                                 np = (union node *)stalloc(sizeof (struct nhere));
1573                                 np->nfile.fd = 0;
1574                         }
1575                         np->type = NHERE;
1576                         heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
1577                         heredoc->here = np;
1578                         if ((c = pgetc()) == '-') {
1579                                 heredoc->striptabs = 1;
1580                         } else {
1581                                 heredoc->striptabs = 0;
1582                                 pungetc();
1583                         }
1584                 } else if (c == '&')
1585                         np->type = NFROMFD;
1586                 else if (c == '>')
1587                         np->type = NFROMTO;
1588                 else {
1589                         np->type = NFROM;
1590                         pungetc();
1591                 }
1592         }
1593         if (fd != '\0')
1594                 np->nfile.fd = digit_val(fd);
1595         redirnode = np;
1596         goto parseredir_return;
1597 }
1598
1599
1600 /*
1601  * Parse a substitution.  At this point, we have read the dollar sign
1602  * and nothing else.
1603  */
1604
1605 parsesub: {
1606         char buf[10];
1607         int subtype;
1608         int typeloc;
1609         int flags;
1610         char *p;
1611         static const char types[] = "}-+?=";
1612         int bracketed_name = 0; /* used to handle ${[0-9]*} variables */
1613         int linno;
1614         int length;
1615         int c1;
1616
1617         c = pgetc();
1618         if (c == '(') { /* $(command) or $((arith)) */
1619                 if (pgetc() == '(') {
1620                         PARSEARITH();
1621                 } else {
1622                         pungetc();
1623                         out = parsebackq(out, &bqlist, 0,
1624                             state[level].syntax == DQSYNTAX &&
1625                             (eofmark == NULL || newvarnest > 0),
1626                             state[level].syntax == DQSYNTAX ||
1627                             state[level].syntax == ARISYNTAX);
1628                 }
1629         } else if (c == '{' || is_name(c) || is_special(c)) {
1630                 USTPUTC(CTLVAR, out);
1631                 typeloc = out - stackblock();
1632                 USTPUTC(VSNORMAL, out);
1633                 subtype = VSNORMAL;
1634                 flags = 0;
1635                 if (c == '{') {
1636                         bracketed_name = 1;
1637                         c = pgetc();
1638                         subtype = 0;
1639                 }
1640 varname:
1641                 if (!is_eof(c) && is_name(c)) {
1642                         length = 0;
1643                         do {
1644                                 STPUTC(c, out);
1645                                 c = pgetc();
1646                                 length++;
1647                         } while (!is_eof(c) && is_in_name(c));
1648                         if (length == 6 &&
1649                             strncmp(out - length, "LINENO", length) == 0) {
1650                                 /* Replace the variable name with the
1651                                  * current line number. */
1652                                 linno = plinno;
1653                                 if (funclinno != 0)
1654                                         linno -= funclinno - 1;
1655                                 snprintf(buf, sizeof(buf), "%d", linno);
1656                                 STADJUST(-6, out);
1657                                 STPUTS(buf, out);
1658                                 flags |= VSLINENO;
1659                         }
1660                 } else if (is_digit(c)) {
1661                         if (bracketed_name) {
1662                                 do {
1663                                         STPUTC(c, out);
1664                                         c = pgetc();
1665                                 } while (is_digit(c));
1666                         } else {
1667                                 STPUTC(c, out);
1668                                 c = pgetc();
1669                         }
1670                 } else if (is_special(c)) {
1671                         c1 = c;
1672                         c = pgetc();
1673                         if (subtype == 0 && c1 == '#') {
1674                                 subtype = VSLENGTH;
1675                                 if (strchr(types, c) == NULL && c != ':' &&
1676                                     c != '#' && c != '%')
1677                                         goto varname;
1678                                 c1 = c;
1679                                 c = pgetc();
1680                                 if (c1 != '}' && c == '}') {
1681                                         pungetc();
1682                                         c = c1;
1683                                         goto varname;
1684                                 }
1685                                 pungetc();
1686                                 c = c1;
1687                                 c1 = '#';
1688                                 subtype = 0;
1689                         }
1690                         USTPUTC(c1, out);
1691                 } else {
1692                         subtype = VSERROR;
1693                         if (c == '}')
1694                                 pungetc();
1695                         else if (c == '\n' || c == PEOF)
1696                                 synerror("Unexpected end of line in substitution");
1697                         else
1698                                 USTPUTC(c, out);
1699                 }
1700                 if (subtype == 0) {
1701                         switch (c) {
1702                         case ':':
1703                                 flags |= VSNUL;
1704                                 c = pgetc();
1705                                 /*FALLTHROUGH*/
1706                         default:
1707                                 p = strchr(types, c);
1708                                 if (p == NULL) {
1709                                         if (c == '\n' || c == PEOF)
1710                                                 synerror("Unexpected end of line in substitution");
1711                                         if (flags == VSNUL)
1712                                                 STPUTC(':', out);
1713                                         STPUTC(c, out);
1714                                         subtype = VSERROR;
1715                                 } else
1716                                         subtype = p - types + VSNORMAL;
1717                                 break;
1718                         case '%':
1719                         case '#':
1720                                 {
1721                                         int cc = c;
1722                                         subtype = c == '#' ? VSTRIMLEFT :
1723                                                              VSTRIMRIGHT;
1724                                         c = pgetc();
1725                                         if (c == cc)
1726                                                 subtype++;
1727                                         else
1728                                                 pungetc();
1729                                         break;
1730                                 }
1731                         }
1732                 } else if (subtype != VSERROR) {
1733                         if (subtype == VSLENGTH && c != '}')
1734                                 subtype = VSERROR;
1735                         pungetc();
1736                 }
1737                 STPUTC('=', out);
1738                 if (state[level].syntax == DQSYNTAX ||
1739                     state[level].syntax == ARISYNTAX)
1740                         flags |= VSQUOTE;
1741                 *(stackblock() + typeloc) = subtype | flags;
1742                 if (subtype != VSNORMAL) {
1743                         if (level + 1 >= maxnest) {
1744                                 maxnest *= 2;
1745                                 if (state == state_static) {
1746                                         state = parser_temp_alloc(
1747                                             maxnest * sizeof(*state));
1748                                         memcpy(state, state_static,
1749                                             MAXNEST_STATIC * sizeof(*state));
1750                                 } else
1751                                         state = parser_temp_realloc(state,
1752                                             maxnest * sizeof(*state));
1753                         }
1754                         level++;
1755                         state[level].parenlevel = 0;
1756                         if (subtype == VSMINUS || subtype == VSPLUS ||
1757                             subtype == VSQUESTION || subtype == VSASSIGN) {
1758                                 /*
1759                                  * For operators that were in the Bourne shell,
1760                                  * inherit the double-quote state.
1761                                  */
1762                                 state[level].syntax = state[level - 1].syntax;
1763                                 state[level].category = TSTATE_VAR_OLD;
1764                         } else {
1765                                 /*
1766                                  * The other operators take a pattern,
1767                                  * so go to BASESYNTAX.
1768                                  * Also, ' and " are now special, even
1769                                  * in here documents.
1770                                  */
1771                                 state[level].syntax = BASESYNTAX;
1772                                 state[level].category = TSTATE_VAR_NEW;
1773                                 newvarnest++;
1774                         }
1775                 }
1776         } else if (c == '\'' && state[level].syntax == BASESYNTAX) {
1777                 /* $'cstylequotes' */
1778                 USTPUTC(CTLQUOTEMARK, out);
1779                 state[level].syntax = SQSYNTAX;
1780                 sqiscstyle = 1;
1781         } else {
1782                 USTPUTC('$', out);
1783                 pungetc();
1784         }
1785         goto parsesub_return;
1786 }
1787
1788
1789 /*
1790  * Parse an arithmetic expansion (indicate start of one and set state)
1791  */
1792 parsearith: {
1793
1794         if (level + 1 >= maxnest) {
1795                 maxnest *= 2;
1796                 if (state == state_static) {
1797                         state = parser_temp_alloc(
1798                             maxnest * sizeof(*state));
1799                         memcpy(state, state_static,
1800                             MAXNEST_STATIC * sizeof(*state));
1801                 } else
1802                         state = parser_temp_realloc(state,
1803                             maxnest * sizeof(*state));
1804         }
1805         level++;
1806         state[level].syntax = ARISYNTAX;
1807         state[level].parenlevel = 0;
1808         state[level].category = TSTATE_ARITH;
1809         USTPUTC(CTLARI, out);
1810         if (state[level - 1].syntax == DQSYNTAX)
1811                 USTPUTC('"',out);
1812         else
1813                 USTPUTC(' ',out);
1814         goto parsearith_return;
1815 }
1816
1817 } /* end of readtoken */
1818
1819
1820
1821 #ifdef mkinit
1822 RESET {
1823         tokpushback = 0;
1824         checkkwd = 0;
1825 }
1826 #endif
1827
1828 /*
1829  * Returns true if the text contains nothing to expand (no dollar signs
1830  * or backquotes).
1831  */
1832
1833 static int
1834 noexpand(char *text)
1835 {
1836         char *p;
1837         char c;
1838
1839         p = text;
1840         while ((c = *p++) != '\0') {
1841                 if ( c == CTLQUOTEMARK)
1842                         continue;
1843                 if (c == CTLESC)
1844                         p++;
1845                 else if (BASESYNTAX[(int)c] == CCTL)
1846                         return 0;
1847         }
1848         return 1;
1849 }
1850
1851
1852 /*
1853  * Return true if the argument is a legal variable name (a letter or
1854  * underscore followed by zero or more letters, underscores, and digits).
1855  */
1856
1857 int
1858 goodname(const char *name)
1859 {
1860         const char *p;
1861
1862         p = name;
1863         if (! is_name(*p))
1864                 return 0;
1865         while (*++p) {
1866                 if (! is_in_name(*p))
1867                         return 0;
1868         }
1869         return 1;
1870 }
1871
1872
1873 int
1874 isassignment(const char *p)
1875 {
1876         if (!is_name(*p))
1877                 return 0;
1878         p++;
1879         for (;;) {
1880                 if (*p == '=')
1881                         return 1;
1882                 else if (!is_in_name(*p))
1883                         return 0;
1884                 p++;
1885         }
1886 }
1887
1888
1889 /*
1890  * Called when an unexpected token is read during the parse.  The argument
1891  * is the token that is expected, or -1 if more than one type of token can
1892  * occur at this point.
1893  */
1894
1895 static void
1896 synexpect(int token)
1897 {
1898         char msg[64];
1899
1900         if (token >= 0) {
1901                 fmtstr(msg, 64, "%s unexpected (expecting %s)",
1902                         tokname[lasttoken], tokname[token]);
1903         } else {
1904                 fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
1905         }
1906         synerror(msg);
1907 }
1908
1909
1910 static void
1911 synerror(const char *msg)
1912 {
1913         if (commandname)
1914                 outfmt(out2, "%s: %d: ", commandname, startlinno);
1915         outfmt(out2, "Syntax error: %s\n", msg);
1916         error(NULL);
1917 }
1918
1919 static void
1920 setprompt(int which)
1921 {
1922         whichprompt = which;
1923
1924 #ifndef NO_HISTORY
1925         if (!el)
1926 #endif
1927         {
1928                 out2str(getprompt(NULL));
1929                 flushout(out2);
1930         }
1931 }
1932
1933 /*
1934  * called by editline -- any expansions to the prompt
1935  *    should be added here.
1936  */
1937 const char *
1938 getprompt(void *unused __unused)
1939 {
1940         static char ps[PROMPTLEN];
1941         const char *fmt;
1942         const char *pwd;
1943         int i, trim;
1944
1945         /*
1946          * Select prompt format.
1947          */
1948         switch (whichprompt) {
1949         case 0:
1950                 fmt = "";
1951                 break;
1952         case 1:
1953                 fmt = ps1val();
1954                 break;
1955         case 2:
1956                 fmt = ps2val();
1957                 break;
1958         default:
1959                 return "??";
1960         }
1961
1962         /*
1963          * Format prompt string.
1964          */
1965         for (i = 0; (i < 127) && (*fmt != '\0'); i++, fmt++)
1966                 if (*fmt == '\\')
1967                         switch (*++fmt) {
1968
1969                                 /*
1970                                  * Hostname.
1971                                  *
1972                                  * \h specifies just the local hostname,
1973                                  * \H specifies fully-qualified hostname.
1974                                  */
1975                         case 'h':
1976                         case 'H':
1977                                 ps[i] = '\0';
1978                                 gethostname(&ps[i], PROMPTLEN - i);
1979                                 /* Skip to end of hostname. */
1980                                 trim = (*fmt == 'h') ? '.' : '\0';
1981                                 while ((ps[i+1] != '\0') && (ps[i+1] != trim))
1982                                         i++;
1983                                 break;
1984
1985                                 /*
1986                                  * Working directory.
1987                                  *
1988                                  * \W specifies just the final component,
1989                                  * \w specifies the entire path.
1990                                  */
1991                         case 'W':
1992                         case 'w':
1993                                 pwd = lookupvar("PWD");
1994                                 if (pwd == NULL)
1995                                         pwd = "?";
1996                                 if (*fmt == 'W' &&
1997                                     *pwd == '/' && pwd[1] != '\0')
1998                                         strlcpy(&ps[i], strrchr(pwd, '/') + 1,
1999                                             PROMPTLEN - i);
2000                                 else
2001                                         strlcpy(&ps[i], pwd, PROMPTLEN - i);
2002                                 /* Skip to end of path. */
2003                                 while (ps[i + 1] != '\0')
2004                                         i++;
2005                                 break;
2006
2007                                 /*
2008                                  * Superuser status.
2009                                  *
2010                                  * '$' for normal users, '#' for root.
2011                                  */
2012                         case '$':
2013                                 ps[i] = (geteuid() != 0) ? '$' : '#';
2014                                 break;
2015
2016                                 /*
2017                                  * A literal \.
2018                                  */
2019                         case '\\':
2020                                 ps[i] = '\\';
2021                                 break;
2022
2023                                 /*
2024                                  * Emit unrecognized formats verbatim.
2025                                  */
2026                         default:
2027                                 ps[i++] = '\\';
2028                                 ps[i] = *fmt;
2029                                 break;
2030                         }
2031                 else
2032                         ps[i] = *fmt;
2033         ps[i] = '\0';
2034         return (ps);
2035 }
2036
2037
2038 const char *
2039 expandstr(char *ps)
2040 {
2041         union node n;
2042         struct jmploc jmploc;
2043         struct jmploc *const savehandler = handler;
2044         const int saveprompt = doprompt;
2045         struct parsefile *const savetopfile = getcurrentfile();
2046         struct parser_temp *const saveparser_temp = parser_temp;
2047         const char *result = NULL;
2048
2049         if (!setjmp(jmploc.loc)) {
2050                 handler = &jmploc;
2051                 parser_temp = NULL;
2052                 setinputstring(ps, 1);
2053                 doprompt = 0;
2054                 readtoken1(pgetc(), DQSYNTAX, __DECONST(char *, "\n\n"), 0);
2055                 if (backquotelist != NULL)
2056                         error("Command substitution not allowed here");
2057
2058                 n.narg.type = NARG;
2059                 n.narg.next = NULL;
2060                 n.narg.text = wordtext;
2061                 n.narg.backquote = backquotelist;
2062
2063                 expandarg(&n, NULL, 0);
2064                 result = stackblock();
2065                 INTOFF;
2066         }
2067         handler = savehandler;
2068         doprompt = saveprompt;
2069         popfilesupto(savetopfile);
2070         if (parser_temp != saveparser_temp) {
2071                 parser_temp_free_all();
2072                 parser_temp = saveparser_temp;
2073         }
2074         if (result != NULL) {
2075                 INTON;
2076         } else if (exception == EXINT)
2077                 raise(SIGINT);
2078         return result;
2079 }