bin/sh/parser.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-3-Clause
   3  *
   4  * Copyright (c) 1991, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Kenneth Almquist.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #ifndef lint
  36 #if 0
  37 static char sccsid[] = "@(#)parser.c    8.7 (Berkeley) 5/16/95";
  38 #endif
  39 #endif /* not lint */
  40 #include <sys/cdefs.h>
  41 __FBSDID("$FreeBSD$");
  42
  43 #include <sys/param.h>
  44 #include <pwd.h>
  45 #include <stdlib.h>
  46 #include <unistd.h>
  47 #include <stdio.h>
  48
  49 #include "shell.h"
  50 #include "parser.h"
  51 #include "nodes.h"
  52 #include "expand.h"     /* defines rmescapes() */
  53 #include "syntax.h"
  54 #include "options.h"
  55 #include "input.h"
  56 #include "output.h"
  57 #include "var.h"
  58 #include "error.h"
  59 #include "memalloc.h"
  60 #include "mystring.h"
  61 #include "alias.h"
  62 #include "show.h"
  63 #include "eval.h"
  64 #include "exec.h"       /* to check for special builtins */
  65 #ifndef NO_HISTORY
  66 #include "myhistedit.h"
  67 #endif
  68
  69 /*
  70  * Shell command parser.
  71  */
  72
  73 #define PROMPTLEN       192
  74
  75 /* values of checkkwd variable */
  76 #define CHKALIAS        0x1
  77 #define CHKKWD          0x2
  78 #define CHKNL           0x4
  79
  80 /* values returned by readtoken */
  81 #include "token.h"
  82
  83
  84
  85 struct heredoc {
  86         struct heredoc *next;   /* next here document in list */
  87         union node *here;               /* redirection node */
  88         char *eofmark;          /* string indicating end of input */
  89         int striptabs;          /* if set, strip leading tabs */
  90 };
  91
  92 struct parser_temp {
  93         struct parser_temp *next;
  94         void *data;
  95 };
  96
  97
  98 static struct heredoc *heredoclist;     /* list of here documents to read */
  99 static int doprompt;            /* if set, prompt the user */
 100 static int needprompt;          /* true if interactive and at start of line */
 101 static int lasttoken;           /* last token read */
 102 static int tokpushback;         /* last token pushed back */
 103 static char *wordtext;          /* text of last word returned by readtoken */
 104 static int checkkwd;
 105 static struct nodelist *backquotelist;
 106 static union node *redirnode;
 107 static struct heredoc *heredoc;
 108 static int quoteflag;           /* set if (part of) last token was quoted */
 109 static int startlinno;          /* line # where last token started */
 110 static int funclinno;           /* line # where the current function started */
 111 static struct parser_temp *parser_temp;
 112
 113 #define NOEOFMARK ((const char *)&heredoclist)
 114
 115
 116 static union node *list(int);
 117 static union node *andor(void);
 118 static union node *pipeline(void);
 119 static union node *command(void);
 120 static union node *simplecmd(union node **, union node *);
 121 static union node *makename(void);
 122 static union node *makebinary(int type, union node *n1, union node *n2);
 123 static void parsefname(void);
 124 static void parseheredoc(void);
 125 static int peektoken(void);
 126 static int readtoken(void);
 127 static int xxreadtoken(void);
 128 static int readtoken1(int, const char *, const char *, int);
 129 static int noexpand(char *);
 130 static void consumetoken(int);
 131 static void synexpect(int) __dead2;
 132 static void synerror(const char *) __dead2;
 133 static void setprompt(int);
 134 static int pgetc_linecont(void);
 135 static void getusername(char *, size_t);
 136
 137
 138 static void *
 139 parser_temp_alloc(size_t len)
 140 {
 141         struct parser_temp *t;
 142
 143         INTOFF;
 144         t = ckmalloc(sizeof(*t));
 145         t->data = NULL;
 146         t->next = parser_temp;
 147         parser_temp = t;
 148         t->data = ckmalloc(len);
 149         INTON;
 150         return t->data;
 151 }
 152
 153
 154 static void *
 155 parser_temp_realloc(void *ptr, size_t len)
 156 {
 157         struct parser_temp *t;
 158
 159         INTOFF;
 160         t = parser_temp;
 161         if (ptr != t->data)
 162                 error("bug: parser_temp_realloc misused");
 163         t->data = ckrealloc(t->data, len);
 164         INTON;
 165         return t->data;
 166 }
 167
 168
 169 static void
 170 parser_temp_free_upto(void *ptr)
 171 {
 172         struct parser_temp *t;
 173         int done = 0;
 174
 175         INTOFF;
 176         while (parser_temp != NULL && !done) {
 177                 t = parser_temp;
 178                 parser_temp = t->next;
 179                 done = t->data == ptr;
 180                 ckfree(t->data);
 181                 ckfree(t);
 182         }
 183         INTON;
 184         if (!done)
 185                 error("bug: parser_temp_free_upto misused");
 186 }
 187
 188
 189 static void
 190 parser_temp_free_all(void)
 191 {
 192         struct parser_temp *t;
 193
 194         INTOFF;
 195         while (parser_temp != NULL) {
 196                 t = parser_temp;
 197                 parser_temp = t->next;
 198                 ckfree(t->data);
 199                 ckfree(t);
 200         }
 201         INTON;
 202 }
 203
 204
 205 /*
 206  * Read and parse a command.  Returns NEOF on end of file.  (NULL is a
 207  * valid parse tree indicating a blank line.)
 208  */
 209
 210 union node *
 211 parsecmd(int interact)
 212 {
 213         int t;
 214
 215         /* This assumes the parser is not re-entered,
 216          * which could happen if we add command substitution on PS1/PS2.
 217          */
 218         parser_temp_free_all();
 219         heredoclist = NULL;
 220
 221         tokpushback = 0;
 222         checkkwd = 0;
 223         doprompt = interact;
 224         if (doprompt)
 225                 setprompt(1);
 226         else
 227                 setprompt(0);
 228         needprompt = 0;
 229         t = readtoken();
 230         if (t == TEOF)
 231                 return NEOF;
 232         if (t == TNL)
 233                 return NULL;
 234         tokpushback++;
 235         return list(1);
 236 }
 237
 238
 239 /*
 240  * Read and parse words for wordexp.
 241  * Returns a list of NARG nodes; NULL if there are no words.
 242  */
 243 union node *
 244 parsewordexp(void)
 245 {
 246         union node *n, *first = NULL, **pnext;
 247         int t;
 248
 249         /* This assumes the parser is not re-entered,
 250          * which could happen if we add command substitution on PS1/PS2.
 251          */
 252         parser_temp_free_all();
 253         heredoclist = NULL;
 254
 255         tokpushback = 0;
 256         checkkwd = 0;
 257         doprompt = 0;
 258         setprompt(0);
 259         needprompt = 0;
 260         pnext = &first;
 261         while ((t = readtoken()) != TEOF) {
 262                 if (t != TWORD)
 263                         synexpect(TWORD);
 264                 n = makename();
 265                 *pnext = n;
 266                 pnext = &n->narg.next;
 267         }
 268         return first;
 269 }
 270
 271
 272 static union node *
 273 list(int nlflag)
 274 {
 275         union node *ntop, *n1, *n2, *n3;
 276         int tok;
 277
 278         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 279         if (!nlflag && tokendlist[peektoken()])
 280                 return NULL;
 281         ntop = n1 = NULL;
 282         for (;;) {
 283                 n2 = andor();
 284                 tok = readtoken();
 285                 if (tok == TBACKGND) {
 286                         if (n2 != NULL && n2->type == NPIPE) {
 287                                 n2->npipe.backgnd = 1;
 288                         } else if (n2 != NULL && n2->type == NREDIR) {
 289                                 n2->type = NBACKGND;
 290                         } else {
 291                                 n3 = (union node *)stalloc(sizeof (struct nredir));
 292                                 n3->type = NBACKGND;
 293                                 n3->nredir.n = n2;
 294                                 n3->nredir.redirect = NULL;
 295                                 n2 = n3;
 296                         }
 297                 }
 298                 if (ntop == NULL)
 299                         ntop = n2;
 300                 else if (n1 == NULL) {
 301                         n1 = makebinary(NSEMI, ntop, n2);
 302                         ntop = n1;
 303                 }
 304                 else {
 305                         n3 = makebinary(NSEMI, n1->nbinary.ch2, n2);
 306                         n1->nbinary.ch2 = n3;
 307                         n1 = n3;
 308                 }
 309                 switch (tok) {
 310                 case TBACKGND:
 311                 case TSEMI:
 312                         tok = readtoken();
 313                         /* FALLTHROUGH */
 314                 case TNL:
 315                         if (tok == TNL) {
 316                                 parseheredoc();
 317                                 if (nlflag)
 318                                         return ntop;
 319                         } else if (tok == TEOF && nlflag) {
 320                                 parseheredoc();
 321                                 return ntop;
 322                         } else {
 323                                 tokpushback++;
 324                         }
 325                         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 326                         if (!nlflag && tokendlist[peektoken()])
 327                                 return ntop;
 328                         break;
 329                 case TEOF:
 330                         if (heredoclist)
 331                                 parseheredoc();
 332                         else
 333                                 pungetc();              /* push back EOF on input */
 334                         return ntop;
 335                 default:
 336                         if (nlflag)
 337                                 synexpect(-1);
 338                         tokpushback++;
 339                         return ntop;
 340                 }
 341         }
 342 }
 343
 344
 345
 346 static union node *
 347 andor(void)
 348 {
 349         union node *n;
 350         int t;
 351
 352         n = pipeline();
 353         for (;;) {
 354                 if ((t = readtoken()) == TAND) {
 355                         t = NAND;
 356                 } else if (t == TOR) {
 357                         t = NOR;
 358                 } else {
 359                         tokpushback++;
 360                         return n;
 361                 }
 362                 n = makebinary(t, n, pipeline());
 363         }
 364 }
 365
 366
 367
 368 static union node *
 369 pipeline(void)
 370 {
 371         union node *n1, *n2, *pipenode;
 372         struct nodelist *lp, *prev;
 373         int negate, t;
 374
 375         negate = 0;
 376         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 377         TRACE(("pipeline: entered\n"));
 378         while (readtoken() == TNOT)
 379                 negate = !negate;
 380         tokpushback++;
 381         n1 = command();
 382         if (readtoken() == TPIPE) {
 383                 pipenode = (union node *)stalloc(sizeof (struct npipe));
 384                 pipenode->type = NPIPE;
 385                 pipenode->npipe.backgnd = 0;
 386                 lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 387                 pipenode->npipe.cmdlist = lp;
 388                 lp->n = n1;
 389                 do {
 390                         prev = lp;
 391                         lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 392                         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 393                         t = readtoken();
 394                         tokpushback++;
 395                         if (t == TNOT)
 396                                 lp->n = pipeline();
 397                         else
 398                                 lp->n = command();
 399                         prev->next = lp;
 400                 } while (readtoken() == TPIPE);
 401                 lp->next = NULL;
 402                 n1 = pipenode;
 403         }
 404         tokpushback++;
 405         if (negate) {
 406                 n2 = (union node *)stalloc(sizeof (struct nnot));
 407                 n2->type = NNOT;
 408                 n2->nnot.com = n1;
 409                 return n2;
 410         } else
 411                 return n1;
 412 }
 413
 414
 415
 416 static union node *
 417 command(void)
 418 {
 419         union node *n1, *n2;
 420         union node *ap, **app;
 421         union node *cp, **cpp;
 422         union node *redir, **rpp;
 423         int t;
 424         int is_subshell;
 425
 426         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 427         is_subshell = 0;
 428         redir = NULL;
 429         n1 = NULL;
 430         rpp = &redir;
 431
 432         /* Check for redirection which may precede command */
 433         while (readtoken() == TREDIR) {
 434                 *rpp = n2 = redirnode;
 435                 rpp = &n2->nfile.next;
 436                 parsefname();
 437         }
 438         tokpushback++;
 439
 440         switch (readtoken()) {
 441         case TIF:
 442                 n1 = (union node *)stalloc(sizeof (struct nif));
 443                 n1->type = NIF;
 444                 if ((n1->nif.test = list(0)) == NULL)
 445                         synexpect(-1);
 446                 consumetoken(TTHEN);
 447                 n1->nif.ifpart = list(0);
 448                 n2 = n1;
 449                 while (readtoken() == TELIF) {
 450                         n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
 451                         n2 = n2->nif.elsepart;
 452                         n2->type = NIF;
 453                         if ((n2->nif.test = list(0)) == NULL)
 454                                 synexpect(-1);
 455                         consumetoken(TTHEN);
 456                         n2->nif.ifpart = list(0);
 457                 }
 458                 if (lasttoken == TELSE)
 459                         n2->nif.elsepart = list(0);
 460                 else {
 461                         n2->nif.elsepart = NULL;
 462                         tokpushback++;
 463                 }
 464                 consumetoken(TFI);
 465                 checkkwd = CHKKWD | CHKALIAS;
 466                 break;
 467         case TWHILE:
 468         case TUNTIL:
 469                 t = lasttoken;
 470                 if ((n1 = list(0)) == NULL)
 471                         synexpect(-1);
 472                 consumetoken(TDO);
 473                 n1 = makebinary((t == TWHILE)? NWHILE : NUNTIL, n1, list(0));
 474                 consumetoken(TDONE);
 475                 checkkwd = CHKKWD | CHKALIAS;
 476                 break;
 477         case TFOR:
 478                 if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
 479                         synerror("Bad for loop variable");
 480                 n1 = (union node *)stalloc(sizeof (struct nfor));
 481                 n1->type = NFOR;
 482                 n1->nfor.var = wordtext;
 483                 checkkwd = CHKNL;
 484                 if (readtoken() == TWORD && !quoteflag &&
 485                     equal(wordtext, "in")) {
 486                         app = &ap;
 487                         while (readtoken() == TWORD) {
 488                                 n2 = makename();
 489                                 *app = n2;
 490                                 app = &n2->narg.next;
 491                         }
 492                         *app = NULL;
 493                         n1->nfor.args = ap;
 494                         if (lasttoken == TNL)
 495                                 tokpushback++;
 496                         else if (lasttoken != TSEMI)
 497                                 synexpect(-1);
 498                 } else {
 499                         static char argvars[5] = {
 500                                 CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'
 501                         };
 502                         n2 = (union node *)stalloc(sizeof (struct narg));
 503                         n2->type = NARG;
 504                         n2->narg.text = argvars;
 505                         n2->narg.backquote = NULL;
 506                         n2->narg.next = NULL;
 507                         n1->nfor.args = n2;
 508                         /*
 509                          * Newline or semicolon here is optional (but note
 510                          * that the original Bourne shell only allowed NL).
 511                          */
 512                         if (lasttoken != TSEMI)
 513                                 tokpushback++;
 514                 }
 515                 checkkwd = CHKNL | CHKKWD | CHKALIAS;
 516                 if ((t = readtoken()) == TDO)
 517                         t = TDONE;
 518                 else if (t == TBEGIN)
 519                         t = TEND;
 520                 else
 521                         synexpect(-1);
 522                 n1->nfor.body = list(0);
 523                 consumetoken(t);
 524                 checkkwd = CHKKWD | CHKALIAS;
 525                 break;
 526         case TCASE:
 527                 n1 = (union node *)stalloc(sizeof (struct ncase));
 528                 n1->type = NCASE;
 529                 consumetoken(TWORD);
 530                 n1->ncase.expr = makename();
 531                 checkkwd = CHKNL;
 532                 if (readtoken() != TWORD || ! equal(wordtext, "in"))
 533                         synerror("expecting \"in\"");
 534                 cpp = &n1->ncase.cases;
 535                 checkkwd = CHKNL | CHKKWD, readtoken();
 536                 while (lasttoken != TESAC) {
 537                         *cpp = cp = (union node *)stalloc(sizeof (struct nclist));
 538                         cp->type = NCLIST;
 539                         app = &cp->nclist.pattern;
 540                         if (lasttoken == TLP)
 541                                 readtoken();
 542                         for (;;) {
 543                                 *app = ap = makename();
 544                                 checkkwd = CHKNL | CHKKWD;
 545                                 if (readtoken() != TPIPE)
 546                                         break;
 547                                 app = &ap->narg.next;
 548                                 readtoken();
 549                         }
 550                         ap->narg.next = NULL;
 551                         if (lasttoken != TRP)
 552                                 synexpect(TRP);
 553                         cp->nclist.body = list(0);
 554
 555                         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 556                         if ((t = readtoken()) != TESAC) {
 557                                 if (t == TENDCASE)
 558                                         ;
 559                                 else if (t == TFALLTHRU)
 560                                         cp->type = NCLISTFALLTHRU;
 561                                 else
 562                                         synexpect(TENDCASE);
 563                                 checkkwd = CHKNL | CHKKWD, readtoken();
 564                         }
 565                         cpp = &cp->nclist.next;
 566                 }
 567                 *cpp = NULL;
 568                 checkkwd = CHKKWD | CHKALIAS;
 569                 break;
 570         case TLP:
 571                 n1 = (union node *)stalloc(sizeof (struct nredir));
 572                 n1->type = NSUBSHELL;
 573                 n1->nredir.n = list(0);
 574                 n1->nredir.redirect = NULL;
 575                 consumetoken(TRP);
 576                 checkkwd = CHKKWD | CHKALIAS;
 577                 is_subshell = 1;
 578                 break;
 579         case TBEGIN:
 580                 n1 = list(0);
 581                 consumetoken(TEND);
 582                 checkkwd = CHKKWD | CHKALIAS;
 583                 break;
 584         /* A simple command must have at least one redirection or word. */
 585         case TBACKGND:
 586         case TSEMI:
 587         case TAND:
 588         case TOR:
 589         case TPIPE:
 590         case TENDCASE:
 591         case TFALLTHRU:
 592         case TEOF:
 593         case TNL:
 594         case TRP:
 595                 if (!redir)
 596                         synexpect(-1);
 597         case TWORD:
 598                 tokpushback++;
 599                 n1 = simplecmd(rpp, redir);
 600                 return n1;
 601         default:
 602                 synexpect(-1);
 603         }
 604
 605         /* Now check for redirection which may follow command */
 606         while (readtoken() == TREDIR) {
 607                 *rpp = n2 = redirnode;
 608                 rpp = &n2->nfile.next;
 609                 parsefname();
 610         }
 611         tokpushback++;
 612         *rpp = NULL;
 613         if (redir) {
 614                 if (!is_subshell) {
 615                         n2 = (union node *)stalloc(sizeof (struct nredir));
 616                         n2->type = NREDIR;
 617                         n2->nredir.n = n1;
 618                         n1 = n2;
 619                 }
 620                 n1->nredir.redirect = redir;
 621         }
 622
 623         return n1;
 624 }
 625
 626
 627 static union node *
 628 simplecmd(union node **rpp, union node *redir)
 629 {
 630         union node *args, **app;
 631         union node **orig_rpp = rpp;
 632         union node *n = NULL;
 633         int special;
 634         int savecheckkwd;
 635
 636         /* If we don't have any redirections already, then we must reset */
 637         /* rpp to be the address of the local redir variable.  */
 638         if (redir == NULL)
 639                 rpp = &redir;
 640
 641         args = NULL;
 642         app = &args;
 643         /*
 644          * We save the incoming value, because we need this for shell
 645          * functions.  There can not be a redirect or an argument between
 646          * the function name and the open parenthesis.
 647          */
 648         orig_rpp = rpp;
 649
 650         savecheckkwd = CHKALIAS;
 651
 652         for (;;) {
 653                 checkkwd = savecheckkwd;
 654                 if (readtoken() == TWORD) {
 655                         n = makename();
 656                         *app = n;
 657                         app = &n->narg.next;
 658                         if (savecheckkwd != 0 && !isassignment(wordtext))
 659                                 savecheckkwd = 0;
 660                 } else if (lasttoken == TREDIR) {
 661                         *rpp = n = redirnode;
 662                         rpp = &n->nfile.next;
 663                         parsefname();   /* read name of redirection file */
 664                 } else if (lasttoken == TLP && app == &args->narg.next
 665                                             && rpp == orig_rpp) {
 666                         /* We have a function */
 667                         consumetoken(TRP);
 668                         funclinno = plinno;
 669                         /*
 670                          * - Require plain text.
 671                          * - Functions with '/' cannot be called.
 672                          * - Reject name=().
 673                          * - Reject ksh extended glob patterns.
 674                          */
 675                         if (!noexpand(n->narg.text) || quoteflag ||
 676                             strchr(n->narg.text, '/') ||
 677                             strchr("!%*+-=?@}~",
 678                                 n->narg.text[strlen(n->narg.text) - 1]))
 679                                 synerror("Bad function name");
 680                         rmescapes(n->narg.text);
 681                         if (find_builtin(n->narg.text, &special) >= 0 &&
 682                             special)
 683                                 synerror("Cannot override a special builtin with a function");
 684                         n->type = NDEFUN;
 685                         n->narg.next = command();
 686                         funclinno = 0;
 687                         return n;
 688                 } else {
 689                         tokpushback++;
 690                         break;
 691                 }
 692         }
 693         *app = NULL;
 694         *rpp = NULL;
 695         n = (union node *)stalloc(sizeof (struct ncmd));
 696         n->type = NCMD;
 697         n->ncmd.args = args;
 698         n->ncmd.redirect = redir;
 699         return n;
 700 }
 701
 702 static union node *
 703 makename(void)
 704 {
 705         union node *n;
 706
 707         n = (union node *)stalloc(sizeof (struct narg));
 708         n->type = NARG;
 709         n->narg.next = NULL;
 710         n->narg.text = wordtext;
 711         n->narg.backquote = backquotelist;
 712         return n;
 713 }
 714
 715 static union node *
 716 makebinary(int type, union node *n1, union node *n2)
 717 {
 718         union node *n;
 719
 720         n = (union node *)stalloc(sizeof (struct nbinary));
 721         n->type = type;
 722         n->nbinary.ch1 = n1;
 723         n->nbinary.ch2 = n2;
 724         return (n);
 725 }
 726
 727 void
 728 forcealias(void)
 729 {
 730         checkkwd |= CHKALIAS;
 731 }
 732
 733 void
 734 fixredir(union node *n, const char *text, int err)
 735 {
 736         TRACE(("Fix redir %s %d\n", text, err));
 737         if (!err)
 738                 n->ndup.vname = NULL;
 739
 740         if (is_digit(text[0]) && text[1] == '\0')
 741                 n->ndup.dupfd = digit_val(text[0]);
 742         else if (text[0] == '-' && text[1] == '\0')
 743                 n->ndup.dupfd = -1;
 744         else {
 745
 746                 if (err)
 747                         synerror("Bad fd number");
 748                 else
 749                         n->ndup.vname = makename();
 750         }
 751 }
 752
 753
 754 static void
 755 parsefname(void)
 756 {
 757         union node *n = redirnode;
 758
 759         consumetoken(TWORD);
 760         if (n->type == NHERE) {
 761                 struct heredoc *here = heredoc;
 762                 struct heredoc *p;
 763
 764                 if (quoteflag == 0)
 765                         n->type = NXHERE;
 766                 TRACE(("Here document %d\n", n->type));
 767                 if (here->striptabs) {
 768                         while (*wordtext == '\t')
 769                                 wordtext++;
 770                 }
 771                 if (! noexpand(wordtext))
 772                         synerror("Illegal eof marker for << redirection");
 773                 rmescapes(wordtext);
 774                 here->eofmark = wordtext;
 775                 here->next = NULL;
 776                 if (heredoclist == NULL)
 777                         heredoclist = here;
 778                 else {
 779                         for (p = heredoclist ; p->next ; p = p->next);
 780                         p->next = here;
 781                 }
 782         } else if (n->type == NTOFD || n->type == NFROMFD) {
 783                 fixredir(n, wordtext, 0);
 784         } else {
 785                 n->nfile.fname = makename();
 786         }
 787 }
 788
 789
 790 /*
 791  * Input any here documents.
 792  */
 793
 794 static void
 795 parseheredoc(void)
 796 {
 797         struct heredoc *here;
 798         union node *n;
 799
 800         while (heredoclist) {
 801                 here = heredoclist;
 802                 heredoclist = here->next;
 803                 if (needprompt) {
 804                         setprompt(2);
 805                         needprompt = 0;
 806                 }
 807                 readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
 808                                 here->eofmark, here->striptabs);
 809                 n = makename();
 810                 here->here->nhere.doc = n;
 811         }
 812 }
 813
 814 static int
 815 peektoken(void)
 816 {
 817         int t;
 818
 819         t = readtoken();
 820         tokpushback++;
 821         return (t);
 822 }
 823
 824 static int
 825 readtoken(void)
 826 {
 827         int t;
 828         struct alias *ap;
 829 #ifdef DEBUG
 830         int alreadyseen = tokpushback;
 831 #endif
 832
 833         top:
 834         t = xxreadtoken();
 835
 836         /*
 837          * eat newlines
 838          */
 839         if (checkkwd & CHKNL) {
 840                 while (t == TNL) {
 841                         parseheredoc();
 842                         t = xxreadtoken();
 843                 }
 844         }
 845
 846         /*
 847          * check for keywords and aliases
 848          */
 849         if (t == TWORD && !quoteflag)
 850         {
 851                 const char * const *pp;
 852
 853                 if (checkkwd & CHKKWD)
 854                         for (pp = parsekwd; *pp; pp++) {
 855                                 if (**pp == *wordtext && equal(*pp, wordtext))
 856                                 {
 857                                         lasttoken = t = pp - parsekwd + KWDOFFSET;
 858                                         TRACE(("keyword %s recognized\n", tokname[t]));
 859                                         goto out;
 860                                 }
 861                         }
 862                 if (checkkwd & CHKALIAS &&
 863                     (ap = lookupalias(wordtext, 1)) != NULL) {
 864                         pushstring(ap->val, strlen(ap->val), ap);
 865                         goto top;
 866                 }
 867         }
 868 out:
 869         if (t != TNOT)
 870                 checkkwd = 0;
 871
 872 #ifdef DEBUG
 873         if (!alreadyseen)
 874             TRACE(("token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 875         else
 876             TRACE(("reread token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 877 #endif
 878         return (t);
 879 }
 880
 881
 882 /*
 883  * Read the next input token.
 884  * If the token is a word, we set backquotelist to the list of cmds in
 885  *      backquotes.  We set quoteflag to true if any part of the word was
 886  *      quoted.
 887  * If the token is TREDIR, then we set redirnode to a structure containing
 888  *      the redirection.
 889  * In all cases, the variable startlinno is set to the number of the line
 890  *      on which the token starts.
 891  *
 892  * [Change comment:  here documents and internal procedures]
 893  * [Readtoken shouldn't have any arguments.  Perhaps we should make the
 894  *  word parsing code into a separate routine.  In this case, readtoken
 895  *  doesn't need to have any internal procedures, but parseword does.
 896  *  We could also make parseoperator in essence the main routine, and
 897  *  have parseword (readtoken1?) handle both words and redirection.]
 898  */
 899
 900 #define RETURN(token)   return lasttoken = token
 901
 902 static int
 903 xxreadtoken(void)
 904 {
 905         int c;
 906
 907         if (tokpushback) {
 908                 tokpushback = 0;
 909                 return lasttoken;
 910         }
 911         if (needprompt) {
 912                 setprompt(2);
 913                 needprompt = 0;
 914         }
 915         startlinno = plinno;
 916         for (;;) {      /* until token or start of word found */
 917                 c = pgetc_macro();
 918                 switch (c) {
 919                 case ' ': case '\t':
 920                         continue;
 921                 case '#':
 922                         while ((c = pgetc()) != '\n' && c != PEOF);
 923                         pungetc();
 924                         continue;
 925                 case '\\':
 926                         if (pgetc() == '\n') {
 927                                 startlinno = ++plinno;
 928                                 if (doprompt)
 929                                         setprompt(2);
 930                                 else
 931                                         setprompt(0);
 932                                 continue;
 933                         }
 934                         pungetc();
 935                         /* FALLTHROUGH */
 936                 default:
 937                         return readtoken1(c, BASESYNTAX, (char *)NULL, 0);
 938                 case '\n':
 939                         plinno++;
 940                         needprompt = doprompt;
 941                         RETURN(TNL);
 942                 case PEOF:
 943                         RETURN(TEOF);
 944                 case '&':
 945                         if (pgetc_linecont() == '&')
 946                                 RETURN(TAND);
 947                         pungetc();
 948                         RETURN(TBACKGND);
 949                 case '|':
 950                         if (pgetc_linecont() == '|')
 951                                 RETURN(TOR);
 952                         pungetc();
 953                         RETURN(TPIPE);
 954                 case ';':
 955                         c = pgetc_linecont();
 956                         if (c == ';')
 957                                 RETURN(TENDCASE);
 958                         else if (c == '&')
 959                                 RETURN(TFALLTHRU);
 960                         pungetc();
 961                         RETURN(TSEMI);
 962                 case '(':
 963                         RETURN(TLP);
 964                 case ')':
 965                         RETURN(TRP);
 966                 }
 967         }
 968 #undef RETURN
 969 }
 970
 971
 972 #define MAXNEST_static 8
 973 struct tokenstate
 974 {
 975         const char *syntax; /* *SYNTAX */
 976         int parenlevel; /* levels of parentheses in arithmetic */
 977         enum tokenstate_category
 978         {
 979                 TSTATE_TOP,
 980                 TSTATE_VAR_OLD, /* ${var+-=?}, inherits dquotes */
 981                 TSTATE_VAR_NEW, /* other ${var...}, own dquote state */
 982                 TSTATE_ARITH
 983         } category;
 984 };
 985
 986
 987 /*
 988  * Check to see whether we are at the end of the here document.  When this
 989  * is called, c is set to the first character of the next input line.  If
 990  * we are at the end of the here document, this routine sets the c to PEOF.
 991  * The new value of c is returned.
 992  */
 993
 994 static int
 995 checkend(int c, const char *eofmark, int striptabs)
 996 {
 997         if (striptabs) {
 998                 while (c == '\t')
 999                         c = pgetc();
1000         }
1001         if (c == *eofmark) {
1002                 int c2;
1003                 const char *q;
1004
1005                 for (q = eofmark + 1; c2 = pgetc(), *q != '\0' && c2 == *q; q++)
1006                         ;
1007                 if ((c2 == PEOF || c2 == '\n') && *q == '\0') {
1008                         c = PEOF;
1009                         if (c2 == '\n') {
1010                                 plinno++;
1011                                 needprompt = doprompt;
1012                         }
1013                 } else {
1014                         pungetc();
1015                         pushstring(eofmark + 1, q - (eofmark + 1), NULL);
1016                 }
1017         } else if (c == '\n' && *eofmark == '\0') {
1018                 c = PEOF;
1019                 plinno++;
1020                 needprompt = doprompt;
1021         }
1022         return (c);
1023 }
1024
1025
1026 /*
1027  * Parse a redirection operator.  The variable "out" points to a string
1028  * specifying the fd to be redirected.  The variable "c" contains the
1029  * first character of the redirection operator.
1030  */
1031
1032 static void
1033 parseredir(char *out, int c)
1034 {
1035         char fd = *out;
1036         union node *np;
1037
1038         np = (union node *)stalloc(sizeof (struct nfile));
1039         if (c == '>') {
1040                 np->nfile.fd = 1;
1041                 c = pgetc_linecont();
1042                 if (c == '>')
1043                         np->type = NAPPEND;
1044                 else if (c == '&')
1045                         np->type = NTOFD;
1046                 else if (c == '|')
1047                         np->type = NCLOBBER;
1048                 else {
1049                         np->type = NTO;
1050                         pungetc();
1051                 }
1052         } else {        /* c == '<' */
1053                 np->nfile.fd = 0;
1054                 c = pgetc_linecont();
1055                 if (c == '<') {
1056                         if (sizeof (struct nfile) != sizeof (struct nhere)) {
1057                                 np = (union node *)stalloc(sizeof (struct nhere));
1058                                 np->nfile.fd = 0;
1059                         }
1060                         np->type = NHERE;
1061                         heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
1062                         heredoc->here = np;
1063                         if ((c = pgetc_linecont()) == '-') {
1064                                 heredoc->striptabs = 1;
1065                         } else {
1066                                 heredoc->striptabs = 0;
1067                                 pungetc();
1068                         }
1069                 } else if (c == '&')
1070                         np->type = NFROMFD;
1071                 else if (c == '>')
1072                         np->type = NFROMTO;
1073                 else {
1074                         np->type = NFROM;
1075                         pungetc();
1076                 }
1077         }
1078         if (fd != '\0')
1079                 np->nfile.fd = digit_val(fd);
1080         redirnode = np;
1081 }
1082
1083 /*
1084  * Called to parse command substitutions.
1085  */
1086
1087 static char *
1088 parsebackq(char *out, struct nodelist **pbqlist,
1089                 int oldstyle, int dblquote, int quoted)
1090 {
1091         struct nodelist **nlpp;
1092         union node *n;
1093         char *volatile str;
1094         struct jmploc jmploc;
1095         struct jmploc *const savehandler = handler;
1096         size_t savelen;
1097         int saveprompt;
1098         const int bq_startlinno = plinno;
1099         char *volatile ostr = NULL;
1100         struct parsefile *const savetopfile = getcurrentfile();
1101         struct heredoc *const saveheredoclist = heredoclist;
1102         struct heredoc *here;
1103
1104         str = NULL;
1105         if (setjmp(jmploc.loc)) {
1106                 popfilesupto(savetopfile);
1107                 if (str)
1108                         ckfree(str);
1109                 if (ostr)
1110                         ckfree(ostr);
1111                 heredoclist = saveheredoclist;
1112                 handler = savehandler;
1113                 if (exception == EXERROR) {
1114                         startlinno = bq_startlinno;
1115                         synerror("Error in command substitution");
1116                 }
1117                 longjmp(handler->loc, 1);
1118         }
1119         INTOFF;
1120         savelen = out - stackblock();
1121         if (savelen > 0) {
1122                 str = ckmalloc(savelen);
1123                 memcpy(str, stackblock(), savelen);
1124         }
1125         handler = &jmploc;
1126         heredoclist = NULL;
1127         INTON;
1128         if (oldstyle) {
1129                 /* We must read until the closing backquote, giving special
1130                    treatment to some slashes, and then push the string and
1131                    reread it as input, interpreting it normally.  */
1132                 char *oout;
1133                 int c;
1134                 int olen;
1135
1136
1137                 STARTSTACKSTR(oout);
1138                 for (;;) {
1139                         if (needprompt) {
1140                                 setprompt(2);
1141                                 needprompt = 0;
1142                         }
1143                         CHECKSTRSPACE(2, oout);
1144                         c = pgetc_linecont();
1145                         if (c == '`')
1146                                 break;
1147                         switch (c) {
1148                         case '\\':
1149                                 c = pgetc();
1150                                 if (c != '\\' && c != '`' && c != '$'
1151                                     && (!dblquote || c != '"'))
1152                                         USTPUTC('\\', oout);
1153                                 break;
1154
1155                         case '\n':
1156                                 plinno++;
1157                                 needprompt = doprompt;
1158                                 break;
1159
1160                         case PEOF:
1161                                 startlinno = plinno;
1162                                 synerror("EOF in backquote substitution");
1163                                 break;
1164
1165                         default:
1166                                 break;
1167                         }
1168                         USTPUTC(c, oout);
1169                 }
1170                 USTPUTC('\0', oout);
1171                 olen = oout - stackblock();
1172                 INTOFF;
1173                 ostr = ckmalloc(olen);
1174                 memcpy(ostr, stackblock(), olen);
1175                 setinputstring(ostr, 1);
1176                 INTON;
1177         }
1178         nlpp = pbqlist;
1179         while (*nlpp)
1180                 nlpp = &(*nlpp)->next;
1181         *nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
1182         (*nlpp)->next = NULL;
1183
1184         if (oldstyle) {
1185                 saveprompt = doprompt;
1186                 doprompt = 0;
1187         }
1188
1189         n = list(0);
1190
1191         if (oldstyle) {
1192                 if (peektoken() != TEOF)
1193                         synexpect(-1);
1194                 doprompt = saveprompt;
1195         } else
1196                 consumetoken(TRP);
1197
1198         (*nlpp)->n = n;
1199         if (oldstyle) {
1200                 /*
1201                  * Start reading from old file again, ignoring any pushed back
1202                  * tokens left from the backquote parsing
1203                  */
1204                 popfile();
1205                 tokpushback = 0;
1206         }
1207         STARTSTACKSTR(out);
1208         CHECKSTRSPACE(savelen + 1, out);
1209         INTOFF;
1210         if (str) {
1211                 memcpy(out, str, savelen);
1212                 STADJUST(savelen, out);
1213                 ckfree(str);
1214                 str = NULL;
1215         }
1216         if (ostr) {
1217                 ckfree(ostr);
1218                 ostr = NULL;
1219         }
1220         here = saveheredoclist;
1221         if (here != NULL) {
1222                 while (here->next != NULL)
1223                         here = here->next;
1224                 here->next = heredoclist;
1225                 heredoclist = saveheredoclist;
1226         }
1227         handler = savehandler;
1228         INTON;
1229         if (quoted)
1230                 USTPUTC(CTLBACKQ | CTLQUOTE, out);
1231         else
1232                 USTPUTC(CTLBACKQ, out);
1233         return out;
1234 }
1235
1236
1237 /*
1238  * Called to parse a backslash escape sequence inside $'...'.
1239  * The backslash has already been read.
1240  */
1241 static char *
1242 readcstyleesc(char *out)
1243 {
1244         int c, vc, i, n;
1245         unsigned int v;
1246
1247         c = pgetc();
1248         switch (c) {
1249         case '\0':
1250                 synerror("Unterminated quoted string");
1251         case '\n':
1252                 plinno++;
1253                 if (doprompt)
1254                         setprompt(2);
1255                 else
1256                         setprompt(0);
1257                 return out;
1258         case '\\':
1259         case '\'':
1260         case '"':
1261                 v = c;
1262                 break;
1263         case 'a': v = '\a'; break;
1264         case 'b': v = '\b'; break;
1265         case 'e': v = '\033'; break;
1266         case 'f': v = '\f'; break;
1267         case 'n': v = '\n'; break;
1268         case 'r': v = '\r'; break;
1269         case 't': v = '\t'; break;
1270         case 'v': v = '\v'; break;
1271         case 'x':
1272                   v = 0;
1273                   for (;;) {
1274                           c = pgetc();
1275                           if (c >= '0' && c <= '9')
1276                                   v = (v << 4) + c - '0';
1277                           else if (c >= 'A' && c <= 'F')
1278                                   v = (v << 4) + c - 'A' + 10;
1279                           else if (c >= 'a' && c <= 'f')
1280                                   v = (v << 4) + c - 'a' + 10;
1281                           else
1282                                   break;
1283                   }
1284                   pungetc();
1285                   break;
1286         case '0': case '1': case '2': case '3':
1287         case '4': case '5': case '6': case '7':
1288                   v = c - '0';
1289                   c = pgetc();
1290                   if (c >= '0' && c <= '7') {
1291                           v <<= 3;
1292                           v += c - '0';
1293                           c = pgetc();
1294                           if (c >= '0' && c <= '7') {
1295                                   v <<= 3;
1296                                   v += c - '0';
1297                           } else
1298                                   pungetc();
1299                   } else
1300                           pungetc();
1301                   break;
1302         case 'c':
1303                   c = pgetc();
1304                   if (c < 0x3f || c > 0x7a || c == 0x60)
1305                           synerror("Bad escape sequence");
1306                   if (c == '\\' && pgetc() != '\\')
1307                           synerror("Bad escape sequence");
1308                   if (c == '?')
1309                           v = 127;
1310                   else
1311                           v = c & 0x1f;
1312                   break;
1313         case 'u':
1314         case 'U':
1315                   n = c == 'U' ? 8 : 4;
1316                   v = 0;
1317                   for (i = 0; i < n; i++) {
1318                           c = pgetc();
1319                           if (c >= '0' && c <= '9')
1320                                   v = (v << 4) + c - '0';
1321                           else if (c >= 'A' && c <= 'F')
1322                                   v = (v << 4) + c - 'A' + 10;
1323                           else if (c >= 'a' && c <= 'f')
1324                                   v = (v << 4) + c - 'a' + 10;
1325                           else
1326                                   synerror("Bad escape sequence");
1327                   }
1328                   if (v == 0 || (v >= 0xd800 && v <= 0xdfff))
1329                           synerror("Bad escape sequence");
1330                   /* We really need iconv here. */
1331                   if (initial_localeisutf8 && v > 127) {
1332                           CHECKSTRSPACE(4, out);
1333                           /*
1334                            * We cannot use wctomb() as the locale may have
1335                            * changed.
1336                            */
1337                           if (v <= 0x7ff) {
1338                                   USTPUTC(0xc0 | v >> 6, out);
1339                                   USTPUTC(0x80 | (v & 0x3f), out);
1340                                   return out;
1341                           } else if (v <= 0xffff) {
1342                                   USTPUTC(0xe0 | v >> 12, out);
1343                                   USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
1344                                   USTPUTC(0x80 | (v & 0x3f), out);
1345                                   return out;
1346                           } else if (v <= 0x10ffff) {
1347                                   USTPUTC(0xf0 | v >> 18, out);
1348                                   USTPUTC(0x80 | ((v >> 12) & 0x3f), out);
1349                                   USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
1350                                   USTPUTC(0x80 | (v & 0x3f), out);
1351                                   return out;
1352                           }
1353                   }
1354                   if (v > 127)
1355                           v = '?';
1356                   break;
1357         default:
1358                   synerror("Bad escape sequence");
1359         }
1360         vc = (char)v;
1361         /*
1362          * We can't handle NUL bytes.
1363          * POSIX says we should skip till the closing quote.
1364          */
1365         if (vc == '\0') {
1366                 while ((c = pgetc()) != '\'') {
1367                         if (c == '\\')
1368                                 c = pgetc();
1369                         if (c == PEOF)
1370                                 synerror("Unterminated quoted string");
1371                         if (c == '\n') {
1372                                 plinno++;
1373                                 if (doprompt)
1374                                         setprompt(2);
1375                                 else
1376                                         setprompt(0);
1377                         }
1378                 }
1379                 pungetc();
1380                 return out;
1381         }
1382         if (SQSYNTAX[vc] == CCTL)
1383                 USTPUTC(CTLESC, out);
1384         USTPUTC(vc, out);
1385         return out;
1386 }
1387
1388
1389 /*
1390  * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
1391  * is not NULL, read a here document.  In the latter case, eofmark is the
1392  * word which marks the end of the document and striptabs is true if
1393  * leading tabs should be stripped from the document.  The argument firstc
1394  * is the first character of the input token or document.
1395  *
1396  * Because C does not have internal subroutines, I have simulated them
1397  * using goto's to implement the subroutine linkage.  The following macros
1398  * will run code that appears at the end of readtoken1.
1399  */
1400
1401 #define PARSESUB()      {goto parsesub; parsesub_return:;}
1402 #define PARSEARITH()    {goto parsearith; parsearith_return:;}
1403
1404 static int
1405 readtoken1(int firstc, char const *initialsyntax, const char *eofmark,
1406     int striptabs)
1407 {
1408         int c = firstc;
1409         char *out;
1410         int len;
1411         struct nodelist *bqlist;
1412         int quotef;
1413         int newvarnest;
1414         int level;
1415         int synentry;
1416         struct tokenstate state_static[MAXNEST_static];
1417         int maxnest = MAXNEST_static;
1418         struct tokenstate *state = state_static;
1419         int sqiscstyle = 0;
1420
1421         startlinno = plinno;
1422         quotef = 0;
1423         bqlist = NULL;
1424         newvarnest = 0;
1425         level = 0;
1426         state[level].syntax = initialsyntax;
1427         state[level].parenlevel = 0;
1428         state[level].category = TSTATE_TOP;
1429
1430         STARTSTACKSTR(out);
1431         loop: { /* for each line, until end of word */
1432                 if (eofmark && eofmark != NOEOFMARK)
1433                         /* set c to PEOF if at end of here document */
1434                         c = checkend(c, eofmark, striptabs);
1435                 for (;;) {      /* until end of line or end of word */
1436                         CHECKSTRSPACE(4, out);  /* permit 4 calls to USTPUTC */
1437
1438                         synentry = state[level].syntax[c];
1439
1440                         switch(synentry) {
1441                         case CNL:       /* '\n' */
1442                                 if (level == 0)
1443                                         goto endword;   /* exit outer loop */
1444                                 /* FALLTHROUGH */
1445                         case CQNL:
1446                                 USTPUTC(c, out);
1447                                 plinno++;
1448                                 if (doprompt)
1449                                         setprompt(2);
1450                                 else
1451                                         setprompt(0);
1452                                 c = pgetc();
1453                                 goto loop;              /* continue outer loop */
1454                         case CSBACK:
1455                                 if (sqiscstyle) {
1456                                         out = readcstyleesc(out);
1457                                         break;
1458                                 }
1459                                 /* FALLTHROUGH */
1460                         case CWORD:
1461                                 USTPUTC(c, out);
1462                                 break;
1463                         case CCTL:
1464                                 if (eofmark == NULL || initialsyntax != SQSYNTAX)
1465                                         USTPUTC(CTLESC, out);
1466                                 USTPUTC(c, out);
1467                                 break;
1468                         case CBACK:     /* backslash */
1469                                 c = pgetc();
1470                                 if (c == PEOF) {
1471                                         USTPUTC('\\', out);
1472                                         pungetc();
1473                                 } else if (c == '\n') {
1474                                         plinno++;
1475                                         if (doprompt)
1476                                                 setprompt(2);
1477                                         else
1478                                                 setprompt(0);
1479                                 } else {
1480                                         if (state[level].syntax == DQSYNTAX &&
1481                                             c != '\\' && c != '`' && c != '$' &&
1482                                             (c != '"' || (eofmark != NULL &&
1483                                                 newvarnest == 0)) &&
1484                                             (c != '}' || state[level].category != TSTATE_VAR_OLD))
1485                                                 USTPUTC('\\', out);
1486                                         if ((eofmark == NULL ||
1487                                             newvarnest > 0) &&
1488                                             state[level].syntax == BASESYNTAX)
1489                                                 USTPUTC(CTLQUOTEMARK, out);
1490                                         if (SQSYNTAX[c] == CCTL)
1491                                                 USTPUTC(CTLESC, out);
1492                                         USTPUTC(c, out);
1493                                         if ((eofmark == NULL ||
1494                                             newvarnest > 0) &&
1495                                             state[level].syntax == BASESYNTAX &&
1496                                             state[level].category == TSTATE_VAR_OLD)
1497                                                 USTPUTC(CTLQUOTEEND, out);
1498                                         quotef++;
1499                                 }
1500                                 break;
1501                         case CSQUOTE:
1502                                 USTPUTC(CTLQUOTEMARK, out);
1503                                 state[level].syntax = SQSYNTAX;
1504                                 sqiscstyle = 0;
1505                                 break;
1506                         case CDQUOTE:
1507                                 USTPUTC(CTLQUOTEMARK, out);
1508                                 state[level].syntax = DQSYNTAX;
1509                                 break;
1510                         case CENDQUOTE:
1511                                 if (eofmark != NULL && newvarnest == 0)
1512                                         USTPUTC(c, out);
1513                                 else {
1514                                         if (state[level].category == TSTATE_VAR_OLD)
1515                                                 USTPUTC(CTLQUOTEEND, out);
1516                                         state[level].syntax = BASESYNTAX;
1517                                         quotef++;
1518                                 }
1519                                 break;
1520                         case CVAR:      /* '$' */
1521                                 PARSESUB();             /* parse substitution */
1522                                 break;
1523                         case CENDVAR:   /* '}' */
1524                                 if (level > 0 &&
1525                                     ((state[level].category == TSTATE_VAR_OLD &&
1526                                       state[level].syntax ==
1527                                       state[level - 1].syntax) ||
1528                                     (state[level].category == TSTATE_VAR_NEW &&
1529                                      state[level].syntax == BASESYNTAX))) {
1530                                         if (state[level].category == TSTATE_VAR_NEW)
1531                                                 newvarnest--;
1532                                         level--;
1533                                         USTPUTC(CTLENDVAR, out);
1534                                 } else {
1535                                         USTPUTC(c, out);
1536                                 }
1537                                 break;
1538                         case CLP:       /* '(' in arithmetic */
1539                                 state[level].parenlevel++;
1540                                 USTPUTC(c, out);
1541                                 break;
1542                         case CRP:       /* ')' in arithmetic */
1543                                 if (state[level].parenlevel > 0) {
1544                                         USTPUTC(c, out);
1545                                         --state[level].parenlevel;
1546                                 } else {
1547                                         if (pgetc_linecont() == ')') {
1548                                                 if (level > 0 &&
1549                                                     state[level].category == TSTATE_ARITH) {
1550                                                         level--;
1551                                                         USTPUTC(CTLENDARI, out);
1552                                                 } else
1553                                                         USTPUTC(')', out);
1554                                         } else {
1555                                                 /*
1556                                                  * unbalanced parens
1557                                                  *  (don't 2nd guess - no error)
1558                                                  */
1559                                                 pungetc();
1560                                                 USTPUTC(')', out);
1561                                         }
1562                                 }
1563                                 break;
1564                         case CBQUOTE:   /* '`' */
1565                                 out = parsebackq(out, &bqlist, 1,
1566                                     state[level].syntax == DQSYNTAX &&
1567                                     (eofmark == NULL || newvarnest > 0),
1568                                     state[level].syntax == DQSYNTAX || state[level].syntax == ARISYNTAX);
1569                                 break;
1570                         case CEOF:
1571                                 goto endword;           /* exit outer loop */
1572                         case CIGN:
1573                                 break;
1574                         default:
1575                                 if (level == 0)
1576                                         goto endword;   /* exit outer loop */
1577                                 USTPUTC(c, out);
1578                         }
1579                         c = pgetc_macro();
1580                 }
1581         }
1582 endword:
1583         if (state[level].syntax == ARISYNTAX)
1584                 synerror("Missing '))'");
1585         if (state[level].syntax != BASESYNTAX && eofmark == NULL)
1586                 synerror("Unterminated quoted string");
1587         if (state[level].category == TSTATE_VAR_OLD ||
1588             state[level].category == TSTATE_VAR_NEW) {
1589                 startlinno = plinno;
1590                 synerror("Missing '}'");
1591         }
1592         if (state != state_static)
1593                 parser_temp_free_upto(state);
1594         USTPUTC('\0', out);
1595         len = out - stackblock();
1596         out = stackblock();
1597         if (eofmark == NULL) {
1598                 if ((c == '>' || c == '<')
1599                  && quotef == 0
1600                  && len <= 2
1601                  && (*out == '\0' || is_digit(*out))) {
1602                         parseredir(out, c);
1603                         return lasttoken = TREDIR;
1604                 } else {
1605                         pungetc();
1606                 }
1607         }
1608         quoteflag = quotef;
1609         backquotelist = bqlist;
1610         grabstackblock(len);
1611         wordtext = out;
1612         return lasttoken = TWORD;
1613 /* end of readtoken routine */
1614
1615
1616 /*
1617  * Parse a substitution.  At this point, we have read the dollar sign
1618  * and nothing else.
1619  */
1620
1621 parsesub: {
1622         int subtype;
1623         int typeloc;
1624         int flags;
1625         char *p;
1626         static const char types[] = "}-+?=";
1627         int linno;
1628         int length;
1629         int c1;
1630
1631         c = pgetc_linecont();
1632         if (c == '(') { /* $(command) or $((arith)) */
1633                 if (pgetc_linecont() == '(') {
1634                         PARSEARITH();
1635                 } else {
1636                         pungetc();
1637                         out = parsebackq(out, &bqlist, 0,
1638                             state[level].syntax == DQSYNTAX &&
1639                             (eofmark == NULL || newvarnest > 0),
1640                             state[level].syntax == DQSYNTAX ||
1641                             state[level].syntax == ARISYNTAX);
1642                 }
1643         } else if (c == '{' || is_name(c) || is_special(c)) {
1644                 USTPUTC(CTLVAR, out);
1645                 typeloc = out - stackblock();
1646                 USTPUTC(VSNORMAL, out);
1647                 subtype = VSNORMAL;
1648                 flags = 0;
1649                 if (c == '{') {
1650                         c = pgetc_linecont();
1651                         subtype = 0;
1652                 }
1653 varname:
1654                 if (!is_eof(c) && is_name(c)) {
1655                         length = 0;
1656                         do {
1657                                 STPUTC(c, out);
1658                                 c = pgetc_linecont();
1659                                 length++;
1660                         } while (!is_eof(c) && is_in_name(c));
1661                         if (length == 6 &&
1662                             strncmp(out - length, "LINENO", length) == 0) {
1663                                 /* Replace the variable name with the
1664                                  * current line number. */
1665                                 STADJUST(-6, out);
1666                                 CHECKSTRSPACE(11, out);
1667                                 linno = plinno;
1668                                 if (funclinno != 0)
1669                                         linno -= funclinno - 1;
1670                                 length = snprintf(out, 11, "%d", linno);
1671                                 if (length > 10)
1672                                         length = 10;
1673                                 out += length;
1674                                 flags |= VSLINENO;
1675                         }
1676                 } else if (is_digit(c)) {
1677                         if (subtype != VSNORMAL) {
1678                                 do {
1679                                         STPUTC(c, out);
1680                                         c = pgetc_linecont();
1681                                 } while (is_digit(c));
1682                         } else {
1683                                 USTPUTC(c, out);
1684                                 c = pgetc_linecont();
1685                         }
1686                 } else if (is_special(c)) {
1687                         c1 = c;
1688                         c = pgetc_linecont();
1689                         if (subtype == 0 && c1 == '#') {
1690                                 subtype = VSLENGTH;
1691                                 if (strchr(types, c) == NULL && c != ':' &&
1692                                     c != '#' && c != '%')
1693                                         goto varname;
1694                                 c1 = c;
1695                                 c = pgetc_linecont();
1696                                 if (c1 != '}' && c == '}') {
1697                                         pungetc();
1698                                         c = c1;
1699                                         goto varname;
1700                                 }
1701                                 pungetc();
1702                                 c = c1;
1703                                 c1 = '#';
1704                                 subtype = 0;
1705                         }
1706                         USTPUTC(c1, out);
1707                 } else {
1708                         subtype = VSERROR;
1709                         if (c == '}')
1710                                 pungetc();
1711                         else if (c == '\n' || c == PEOF)
1712                                 synerror("Unexpected end of line in substitution");
1713                         else if (BASESYNTAX[c] != CCTL)
1714                                 USTPUTC(c, out);
1715                 }
1716                 if (subtype == 0) {
1717                         switch (c) {
1718                         case ':':
1719                                 flags |= VSNUL;
1720                                 c = pgetc_linecont();
1721                                 /*FALLTHROUGH*/
1722                         default:
1723                                 p = strchr(types, c);
1724                                 if (p == NULL) {
1725                                         if (c == '\n' || c == PEOF)
1726                                                 synerror("Unexpected end of line in substitution");
1727                                         if (flags == VSNUL)
1728                                                 STPUTC(':', out);
1729                                         if (BASESYNTAX[c] != CCTL)
1730                                                 STPUTC(c, out);
1731                                         subtype = VSERROR;
1732                                 } else
1733                                         subtype = p - types + VSNORMAL;
1734                                 break;
1735                         case '%':
1736                         case '#':
1737                                 {
1738                                         int cc = c;
1739                                         subtype = c == '#' ? VSTRIMLEFT :
1740                                                              VSTRIMRIGHT;
1741                                         c = pgetc_linecont();
1742                                         if (c == cc)
1743                                                 subtype++;
1744                                         else
1745                                                 pungetc();
1746                                         break;
1747                                 }
1748                         }
1749                 } else if (subtype != VSERROR) {
1750                         if (subtype == VSLENGTH && c != '}')
1751                                 subtype = VSERROR;
1752                         pungetc();
1753                 }
1754                 STPUTC('=', out);
1755                 if (state[level].syntax == DQSYNTAX ||
1756                     state[level].syntax == ARISYNTAX)
1757                         flags |= VSQUOTE;
1758                 *(stackblock() + typeloc) = subtype | flags;
1759                 if (subtype != VSNORMAL) {
1760                         if (level + 1 >= maxnest) {
1761                                 maxnest *= 2;
1762                                 if (state == state_static) {
1763                                         state = parser_temp_alloc(
1764                                             maxnest * sizeof(*state));
1765                                         memcpy(state, state_static,
1766                                             MAXNEST_static * sizeof(*state));
1767                                 } else
1768                                         state = parser_temp_realloc(state,
1769                                             maxnest * sizeof(*state));
1770                         }
1771                         level++;
1772                         state[level].parenlevel = 0;
1773                         if (subtype == VSMINUS || subtype == VSPLUS ||
1774                             subtype == VSQUESTION || subtype == VSASSIGN) {
1775                                 /*
1776                                  * For operators that were in the Bourne shell,
1777                                  * inherit the double-quote state.
1778                                  */
1779                                 state[level].syntax = state[level - 1].syntax;
1780                                 state[level].category = TSTATE_VAR_OLD;
1781                         } else {
1782                                 /*
1783                                  * The other operators take a pattern,
1784                                  * so go to BASESYNTAX.
1785                                  * Also, ' and " are now special, even
1786                                  * in here documents.
1787                                  */
1788                                 state[level].syntax = BASESYNTAX;
1789                                 state[level].category = TSTATE_VAR_NEW;
1790                                 newvarnest++;
1791                         }
1792                 }
1793         } else if (c == '\'' && state[level].syntax == BASESYNTAX) {
1794                 /* $'cstylequotes' */
1795                 USTPUTC(CTLQUOTEMARK, out);
1796                 state[level].syntax = SQSYNTAX;
1797                 sqiscstyle = 1;
1798         } else {
1799                 USTPUTC('$', out);
1800                 pungetc();
1801         }
1802         goto parsesub_return;
1803 }
1804
1805
1806 /*
1807  * Parse an arithmetic expansion (indicate start of one and set state)
1808  */
1809 parsearith: {
1810
1811         if (level + 1 >= maxnest) {
1812                 maxnest *= 2;
1813                 if (state == state_static) {
1814                         state = parser_temp_alloc(
1815                             maxnest * sizeof(*state));
1816                         memcpy(state, state_static,
1817                             MAXNEST_static * sizeof(*state));
1818                 } else
1819                         state = parser_temp_realloc(state,
1820                             maxnest * sizeof(*state));
1821         }
1822         level++;
1823         state[level].syntax = ARISYNTAX;
1824         state[level].parenlevel = 0;
1825         state[level].category = TSTATE_ARITH;
1826         USTPUTC(CTLARI, out);
1827         if (state[level - 1].syntax == DQSYNTAX)
1828                 USTPUTC('"',out);
1829         else
1830                 USTPUTC(' ',out);
1831         goto parsearith_return;
1832 }
1833
1834 } /* end of readtoken */
1835
1836
1837 /*
1838  * Returns true if the text contains nothing to expand (no dollar signs
1839  * or backquotes).
1840  */
1841
1842 static int
1843 noexpand(char *text)
1844 {
1845         char *p;
1846         char c;
1847
1848         p = text;
1849         while ((c = *p++) != '\0') {
1850                 if ( c == CTLQUOTEMARK)
1851                         continue;
1852                 if (c == CTLESC)
1853                         p++;
1854                 else if (BASESYNTAX[(int)c] == CCTL)
1855                         return 0;
1856         }
1857         return 1;
1858 }
1859
1860
1861 /*
1862  * Return true if the argument is a legal variable name (a letter or
1863  * underscore followed by zero or more letters, underscores, and digits).
1864  */
1865
1866 int
1867 goodname(const char *name)
1868 {
1869         const char *p;
1870
1871         p = name;
1872         if (! is_name(*p))
1873                 return 0;
1874         while (*++p) {
1875                 if (! is_in_name(*p))
1876                         return 0;
1877         }
1878         return 1;
1879 }
1880
1881
1882 int
1883 isassignment(const char *p)
1884 {
1885         if (!is_name(*p))
1886                 return 0;
1887         p++;
1888         for (;;) {
1889                 if (*p == '=')
1890                         return 1;
1891                 else if (!is_in_name(*p))
1892                         return 0;
1893                 p++;
1894         }
1895 }
1896
1897
1898 static void
1899 consumetoken(int token)
1900 {
1901         if (readtoken() != token)
1902                 synexpect(token);
1903 }
1904
1905
1906 /*
1907  * Called when an unexpected token is read during the parse.  The argument
1908  * is the token that is expected, or -1 if more than one type of token can
1909  * occur at this point.
1910  */
1911
1912 static void
1913 synexpect(int token)
1914 {
1915         char msg[64];
1916
1917         if (token >= 0) {
1918                 fmtstr(msg, 64, "%s unexpected (expecting %s)",
1919                         tokname[lasttoken], tokname[token]);
1920         } else {
1921                 fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
1922         }
1923         synerror(msg);
1924 }
1925
1926
1927 static void
1928 synerror(const char *msg)
1929 {
1930         if (commandname)
1931                 outfmt(out2, "%s: %d: ", commandname, startlinno);
1932         else if (arg0)
1933                 outfmt(out2, "%s: ", arg0);
1934         outfmt(out2, "Syntax error: %s\n", msg);
1935         error((char *)NULL);
1936 }
1937
1938 static void
1939 setprompt(int which)
1940 {
1941         whichprompt = which;
1942         if (which == 0)
1943                 return;
1944
1945 #ifndef NO_HISTORY
1946         if (!el)
1947 #endif
1948         {
1949                 out2str(getprompt(NULL));
1950                 flushout(out2);
1951         }
1952 }
1953
1954 static int
1955 pgetc_linecont(void)
1956 {
1957         int c;
1958
1959         while ((c = pgetc_macro()) == '\\') {
1960                 c = pgetc();
1961                 if (c == '\n') {
1962                         plinno++;
1963                         if (doprompt)
1964                                 setprompt(2);
1965                         else
1966                                 setprompt(0);
1967                 } else {
1968                         pungetc();
1969                         /* Allow the backslash to be pushed back. */
1970                         pushstring("\\", 1, NULL);
1971                         return (pgetc());
1972                 }
1973         }
1974         return (c);
1975 }
1976
1977
1978 static struct passwd *
1979 getpwlogin(void)
1980 {
1981         const char *login;
1982
1983         login = getlogin();
1984         if (login == NULL)
1985                 return (NULL);
1986
1987         return (getpwnam(login));
1988 }
1989
1990
1991 static void
1992 getusername(char *name, size_t namelen)
1993 {
1994         static char cached_name[MAXLOGNAME];
1995         struct passwd *pw;
1996         uid_t euid;
1997
1998         if (cached_name[0] == '\0') {
1999                 euid = geteuid();
2000
2001                 /*
2002                  * Handle the case when there is more than one
2003                  * login with the same UID, or when the login
2004                  * returned by getlogin(2) does no longer match
2005                  * the current UID.
2006                  */
2007                 pw = getpwlogin();
2008                 if (pw == NULL || pw->pw_uid != euid)
2009                         pw = getpwuid(euid);
2010
2011                 if (pw != NULL) {
2012                         strlcpy(cached_name, pw->pw_name,
2013                             sizeof(cached_name));
2014                 } else {
2015                         snprintf(cached_name, sizeof(cached_name),
2016                             "%u", euid);
2017                 }
2018         }
2019
2020         strlcpy(name, cached_name, namelen);
2021 }
2022
2023
2024 /*
2025  * called by editline -- any expansions to the prompt
2026  *    should be added here.
2027  */
2028 char *
2029 getprompt(void *unused __unused)
2030 {
2031         static char ps[PROMPTLEN];
2032         const char *fmt;
2033         const char *home;
2034         const char *pwd;
2035         size_t homelen;
2036         int i, trim;
2037         static char internal_error[] = "??";
2038
2039         /*
2040          * Select prompt format.
2041          */
2042         switch (whichprompt) {
2043         case 0:
2044                 fmt = "";
2045                 break;
2046         case 1:
2047                 fmt = ps1val();
2048                 break;
2049         case 2:
2050                 fmt = ps2val();
2051                 break;
2052         default:
2053                 return internal_error;
2054         }
2055
2056         /*
2057          * Format prompt string.
2058          */
2059         for (i = 0; (i < PROMPTLEN - 1) && (*fmt != '\0'); i++, fmt++)
2060                 if (*fmt == '\\')
2061                         switch (*++fmt) {
2062
2063                                 /*
2064                                  * Non-printing sequence begin and end.
2065                                  */
2066                         case '[':
2067                         case ']':
2068                                 ps[i] = '\001';
2069                                 break;
2070
2071                                 /*
2072                                  * Literal \ and some ASCII characters:
2073                                  * \a   BEL
2074                                  * \e   ESC
2075                                  * \r   CR
2076                                  */
2077                         case '\\':
2078                         case 'a':
2079                         case 'e':
2080                         case 'r':
2081                                 if (*fmt == 'a')
2082                                         ps[i] = '\007';
2083                                 else if (*fmt == 'e')
2084                                         ps[i] = '\033';
2085                                 else if (*fmt == 'r')
2086                                         ps[i] = '\r';
2087                                 else
2088                                         ps[i] = '\\';
2089                                 break;
2090
2091                                 /*
2092                                  * CRLF sequence
2093                                  */
2094                         case 'n':
2095                                 if (i < PROMPTLEN - 3) {
2096                                         ps[i++] = '\r';
2097                                         ps[i] = '\n';
2098                                 }
2099                                 break;
2100
2101                                 /*
2102                                  * Hostname.
2103                                  *
2104                                  * \h specifies just the local hostname,
2105                                  * \H specifies fully-qualified hostname.
2106                                  */
2107                         case 'h':
2108                         case 'H':
2109                                 ps[i] = '\0';
2110                                 gethostname(&ps[i], PROMPTLEN - i - 1);
2111                                 ps[PROMPTLEN - 1] = '\0';
2112                                 /* Skip to end of hostname. */
2113                                 trim = (*fmt == 'h') ? '.' : '\0';
2114                                 while ((ps[i] != '\0') && (ps[i] != trim))
2115                                         i++;
2116                                 --i;
2117                                 break;
2118
2119                                 /*
2120                                  * User name.
2121                                  */
2122                         case 'u':
2123                                 ps[i] = '\0';
2124                                 getusername(&ps[i], PROMPTLEN - i);
2125                                 /* Skip to end of username. */
2126                                 while (ps[i + 1] != '\0')
2127                                         i++;
2128                                 break;
2129
2130                                 /*
2131                                  * Working directory.
2132                                  *
2133                                  * \W specifies just the final component,
2134                                  * \w specifies the entire path.
2135                                  */
2136                         case 'W':
2137                         case 'w':
2138                                 pwd = lookupvar("PWD");
2139                                 if (pwd == NULL || *pwd == '\0')
2140                                         pwd = "?";
2141                                 if (*fmt == 'W' &&
2142                                     *pwd == '/' && pwd[1] != '\0')
2143                                         strlcpy(&ps[i], strrchr(pwd, '/') + 1,
2144                                             PROMPTLEN - i);
2145                                 else {
2146                                         home = lookupvar("HOME");
2147                                         if (home != NULL)
2148                                                 homelen = strlen(home);
2149                                         if (home != NULL &&
2150                                             strcmp(home, "/") != 0 &&
2151                                             strncmp(pwd, home, homelen) == 0 &&
2152                                             (pwd[homelen] == '/' ||
2153                                             pwd[homelen] == '\0')) {
2154                                                 strlcpy(&ps[i], "~",
2155                                                     PROMPTLEN - i);
2156                                                 strlcpy(&ps[i + 1],
2157                                                     pwd + homelen,
2158                                                     PROMPTLEN - i - 1);
2159                                         } else {
2160                                                 strlcpy(&ps[i], pwd, PROMPTLEN - i);
2161                                         }
2162                                 }
2163                                 /* Skip to end of path. */
2164                                 while (ps[i + 1] != '\0')
2165                                         i++;
2166                                 break;
2167
2168                                 /*
2169                                  * Superuser status.
2170                                  *
2171                                  * '$' for normal users, '#' for root.
2172                                  */
2173                         case '$':
2174                                 ps[i] = (geteuid() != 0) ? '$' : '#';
2175                                 break;
2176
2177                                 /*
2178                                  * Emit unrecognized formats verbatim.
2179                                  */
2180                         default:
2181                                 ps[i] = '\\';
2182                                 if (i < PROMPTLEN - 2)
2183                                         ps[++i] = *fmt;
2184                                 break;
2185                         }
2186                 else
2187                         ps[i] = *fmt;
2188         ps[i] = '\0';
2189         return (ps);
2190 }
2191
2192
2193 const char *
2194 expandstr(const char *ps)
2195 {
2196         union node n;
2197         struct jmploc jmploc;
2198         struct jmploc *const savehandler = handler;
2199         const int saveprompt = doprompt;
2200         struct parsefile *const savetopfile = getcurrentfile();
2201         struct parser_temp *const saveparser_temp = parser_temp;
2202         const char *result = NULL;
2203
2204         if (!setjmp(jmploc.loc)) {
2205                 handler = &jmploc;
2206                 parser_temp = NULL;
2207                 setinputstring(ps, 1);
2208                 doprompt = 0;
2209                 readtoken1(pgetc(), DQSYNTAX, NOEOFMARK, 0);
2210                 if (backquotelist != NULL)
2211                         error("Command substitution not allowed here");
2212
2213                 n.narg.type = NARG;
2214                 n.narg.next = NULL;
2215                 n.narg.text = wordtext;
2216                 n.narg.backquote = backquotelist;
2217
2218                 expandarg(&n, NULL, 0);
2219                 result = stackblock();
2220                 INTOFF;
2221         }
2222         handler = savehandler;
2223         doprompt = saveprompt;
2224         popfilesupto(savetopfile);
2225         if (parser_temp != saveparser_temp) {
2226                 parser_temp_free_all();
2227                 parser_temp = saveparser_temp;
2228         }
2229         if (result != NULL) {
2230                 INTON;
2231         } else if (exception == EXINT)
2232                 raise(SIGINT);
2233         return result;
2234 }