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: head/bin/sh/parser.c 343399 2019-01-24 11:59:46Z trasz $");
  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       128
  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                 while (readtoken() == TNL)
 484                         ;
 485                 if (lasttoken == TWORD && ! quoteflag && 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 && lasttoken != TSEMI)
 495                                 synexpect(-1);
 496                 } else {
 497                         static char argvars[5] = {
 498                                 CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'
 499                         };
 500                         n2 = (union node *)stalloc(sizeof (struct narg));
 501                         n2->type = NARG;
 502                         n2->narg.text = argvars;
 503                         n2->narg.backquote = NULL;
 504                         n2->narg.next = NULL;
 505                         n1->nfor.args = n2;
 506                         /*
 507                          * Newline or semicolon here is optional (but note
 508                          * that the original Bourne shell only allowed NL).
 509                          */
 510                         if (lasttoken != TNL && lasttoken != TSEMI)
 511                                 tokpushback++;
 512                 }
 513                 checkkwd = CHKNL | CHKKWD | CHKALIAS;
 514                 if ((t = readtoken()) == TDO)
 515                         t = TDONE;
 516                 else if (t == TBEGIN)
 517                         t = TEND;
 518                 else
 519                         synexpect(-1);
 520                 n1->nfor.body = list(0);
 521                 consumetoken(t);
 522                 checkkwd = CHKKWD | CHKALIAS;
 523                 break;
 524         case TCASE:
 525                 n1 = (union node *)stalloc(sizeof (struct ncase));
 526                 n1->type = NCASE;
 527                 consumetoken(TWORD);
 528                 n1->ncase.expr = makename();
 529                 while (readtoken() == TNL);
 530                 if (lasttoken != TWORD || ! equal(wordtext, "in"))
 531                         synerror("expecting \"in\"");
 532                 cpp = &n1->ncase.cases;
 533                 checkkwd = CHKNL | CHKKWD, readtoken();
 534                 while (lasttoken != TESAC) {
 535                         *cpp = cp = (union node *)stalloc(sizeof (struct nclist));
 536                         cp->type = NCLIST;
 537                         app = &cp->nclist.pattern;
 538                         if (lasttoken == TLP)
 539                                 readtoken();
 540                         for (;;) {
 541                                 *app = ap = makename();
 542                                 checkkwd = CHKNL | CHKKWD;
 543                                 if (readtoken() != TPIPE)
 544                                         break;
 545                                 app = &ap->narg.next;
 546                                 readtoken();
 547                         }
 548                         ap->narg.next = NULL;
 549                         if (lasttoken != TRP)
 550                                 synexpect(TRP);
 551                         cp->nclist.body = list(0);
 552
 553                         checkkwd = CHKNL | CHKKWD | CHKALIAS;
 554                         if ((t = readtoken()) != TESAC) {
 555                                 if (t == TENDCASE)
 556                                         ;
 557                                 else if (t == TFALLTHRU)
 558                                         cp->type = NCLISTFALLTHRU;
 559                                 else
 560                                         synexpect(TENDCASE);
 561                                 checkkwd = CHKNL | CHKKWD, readtoken();
 562                         }
 563                         cpp = &cp->nclist.next;
 564                 }
 565                 *cpp = NULL;
 566                 checkkwd = CHKKWD | CHKALIAS;
 567                 break;
 568         case TLP:
 569                 n1 = (union node *)stalloc(sizeof (struct nredir));
 570                 n1->type = NSUBSHELL;
 571                 n1->nredir.n = list(0);
 572                 n1->nredir.redirect = NULL;
 573                 consumetoken(TRP);
 574                 checkkwd = CHKKWD | CHKALIAS;
 575                 is_subshell = 1;
 576                 break;
 577         case TBEGIN:
 578                 n1 = list(0);
 579                 consumetoken(TEND);
 580                 checkkwd = CHKKWD | CHKALIAS;
 581                 break;
 582         /* A simple command must have at least one redirection or word. */
 583         case TBACKGND:
 584         case TSEMI:
 585         case TAND:
 586         case TOR:
 587         case TPIPE:
 588         case TENDCASE:
 589         case TFALLTHRU:
 590         case TEOF:
 591         case TNL:
 592         case TRP:
 593                 if (!redir)
 594                         synexpect(-1);
 595                 /* FALLTHROUGH */
 596         case TWORD:
 597                 tokpushback++;
 598                 n1 = simplecmd(rpp, redir);
 599                 return n1;
 600         default:
 601                 synexpect(-1);
 602         }
 603
 604         /* Now check for redirection which may follow command */
 605         while (readtoken() == TREDIR) {
 606                 *rpp = n2 = redirnode;
 607                 rpp = &n2->nfile.next;
 608                 parsefname();
 609         }
 610         tokpushback++;
 611         *rpp = NULL;
 612         if (redir) {
 613                 if (!is_subshell) {
 614                         n2 = (union node *)stalloc(sizeof (struct nredir));
 615                         n2->type = NREDIR;
 616                         n2->nredir.n = n1;
 617                         n1 = n2;
 618                 }
 619                 n1->nredir.redirect = redir;
 620         }
 621
 622         return n1;
 623 }
 624
 625
 626 static union node *
 627 simplecmd(union node **rpp, union node *redir)
 628 {
 629         union node *args, **app;
 630         union node **orig_rpp = rpp;
 631         union node *n = NULL;
 632         int special;
 633         int savecheckkwd;
 634
 635         /* If we don't have any redirections already, then we must reset */
 636         /* rpp to be the address of the local redir variable.  */
 637         if (redir == NULL)
 638                 rpp = &redir;
 639
 640         args = NULL;
 641         app = &args;
 642         /*
 643          * We save the incoming value, because we need this for shell
 644          * functions.  There can not be a redirect or an argument between
 645          * the function name and the open parenthesis.
 646          */
 647         orig_rpp = rpp;
 648
 649         savecheckkwd = CHKALIAS;
 650
 651         for (;;) {
 652                 checkkwd = savecheckkwd;
 653                 if (readtoken() == TWORD) {
 654                         n = makename();
 655                         *app = n;
 656                         app = &n->narg.next;
 657                         if (savecheckkwd != 0 && !isassignment(wordtext))
 658                                 savecheckkwd = 0;
 659                 } else if (lasttoken == TREDIR) {
 660                         *rpp = n = redirnode;
 661                         rpp = &n->nfile.next;
 662                         parsefname();   /* read name of redirection file */
 663                 } else if (lasttoken == TLP && app == &args->narg.next
 664                                             && rpp == orig_rpp) {
 665                         /* We have a function */
 666                         consumetoken(TRP);
 667                         funclinno = plinno;
 668                         /*
 669                          * - Require plain text.
 670                          * - Functions with '/' cannot be called.
 671                          * - Reject name=().
 672                          * - Reject ksh extended glob patterns.
 673                          */
 674                         if (!noexpand(n->narg.text) || quoteflag ||
 675                             strchr(n->narg.text, '/') ||
 676                             strchr("!%*+-=?@}~",
 677                                 n->narg.text[strlen(n->narg.text) - 1]))
 678                                 synerror("Bad function name");
 679                         rmescapes(n->narg.text);
 680                         if (find_builtin(n->narg.text, &special) >= 0 &&
 681                             special)
 682                                 synerror("Cannot override a special builtin with a function");
 683                         n->type = NDEFUN;
 684                         n->narg.next = command();
 685                         funclinno = 0;
 686                         return n;
 687                 } else {
 688                         tokpushback++;
 689                         break;
 690                 }
 691         }
 692         *app = NULL;
 693         *rpp = NULL;
 694         n = (union node *)stalloc(sizeof (struct ncmd));
 695         n->type = NCMD;
 696         n->ncmd.args = args;
 697         n->ncmd.redirect = redir;
 698         return n;
 699 }
 700
 701 static union node *
 702 makename(void)
 703 {
 704         union node *n;
 705
 706         n = (union node *)stalloc(sizeof (struct narg));
 707         n->type = NARG;
 708         n->narg.next = NULL;
 709         n->narg.text = wordtext;
 710         n->narg.backquote = backquotelist;
 711         return n;
 712 }
 713
 714 static union node *
 715 makebinary(int type, union node *n1, union node *n2)
 716 {
 717         union node *n;
 718
 719         n = (union node *)stalloc(sizeof (struct nbinary));
 720         n->type = type;
 721         n->nbinary.ch1 = n1;
 722         n->nbinary.ch2 = n2;
 723         return (n);
 724 }
 725
 726 void
 727 forcealias(void)
 728 {
 729         checkkwd |= CHKALIAS;
 730 }
 731
 732 void
 733 fixredir(union node *n, const char *text, int err)
 734 {
 735         TRACE(("Fix redir %s %d\n", text, err));
 736         if (!err)
 737                 n->ndup.vname = NULL;
 738
 739         if (is_digit(text[0]) && text[1] == '\0')
 740                 n->ndup.dupfd = digit_val(text[0]);
 741         else if (text[0] == '-' && text[1] == '\0')
 742                 n->ndup.dupfd = -1;
 743         else {
 744
 745                 if (err)
 746                         synerror("Bad fd number");
 747                 else
 748                         n->ndup.vname = makename();
 749         }
 750 }
 751
 752
 753 static void
 754 parsefname(void)
 755 {
 756         union node *n = redirnode;
 757
 758         consumetoken(TWORD);
 759         if (n->type == NHERE) {
 760                 struct heredoc *here = heredoc;
 761                 struct heredoc *p;
 762
 763                 if (quoteflag == 0)
 764                         n->type = NXHERE;
 765                 TRACE(("Here document %d\n", n->type));
 766                 if (here->striptabs) {
 767                         while (*wordtext == '\t')
 768                                 wordtext++;
 769                 }
 770                 if (! noexpand(wordtext))
 771                         synerror("Illegal eof marker for << redirection");
 772                 rmescapes(wordtext);
 773                 here->eofmark = wordtext;
 774                 here->next = NULL;
 775                 if (heredoclist == NULL)
 776                         heredoclist = here;
 777                 else {
 778                         for (p = heredoclist ; p->next ; p = p->next);
 779                         p->next = here;
 780                 }
 781         } else if (n->type == NTOFD || n->type == NFROMFD) {
 782                 fixredir(n, wordtext, 0);
 783         } else {
 784                 n->nfile.fname = makename();
 785         }
 786 }
 787
 788
 789 /*
 790  * Input any here documents.
 791  */
 792
 793 static void
 794 parseheredoc(void)
 795 {
 796         struct heredoc *here;
 797         union node *n;
 798
 799         while (heredoclist) {
 800                 here = heredoclist;
 801                 heredoclist = here->next;
 802                 if (needprompt) {
 803                         setprompt(2);
 804                         needprompt = 0;
 805                 }
 806                 readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
 807                                 here->eofmark, here->striptabs);
 808                 n = makename();
 809                 here->here->nhere.doc = n;
 810         }
 811 }
 812
 813 static int
 814 peektoken(void)
 815 {
 816         int t;
 817
 818         t = readtoken();
 819         tokpushback++;
 820         return (t);
 821 }
 822
 823 static int
 824 readtoken(void)
 825 {
 826         int t;
 827         struct alias *ap;
 828 #ifdef DEBUG
 829         int alreadyseen = tokpushback;
 830 #endif
 831
 832         top:
 833         t = xxreadtoken();
 834
 835         /*
 836          * eat newlines
 837          */
 838         if (checkkwd & CHKNL) {
 839                 while (t == TNL) {
 840                         parseheredoc();
 841                         t = xxreadtoken();
 842                 }
 843         }
 844
 845         /*
 846          * check for keywords and aliases
 847          */
 848         if (t == TWORD && !quoteflag)
 849         {
 850                 const char * const *pp;
 851
 852                 if (checkkwd & CHKKWD)
 853                         for (pp = parsekwd; *pp; pp++) {
 854                                 if (**pp == *wordtext && equal(*pp, wordtext))
 855                                 {
 856                                         lasttoken = t = pp - parsekwd + KWDOFFSET;
 857                                         TRACE(("keyword %s recognized\n", tokname[t]));
 858                                         goto out;
 859                                 }
 860                         }
 861                 if (checkkwd & CHKALIAS &&
 862                     (ap = lookupalias(wordtext, 1)) != NULL) {
 863                         pushstring(ap->val, strlen(ap->val), ap);
 864                         goto top;
 865                 }
 866         }
 867 out:
 868         if (t != TNOT)
 869                 checkkwd = 0;
 870
 871 #ifdef DEBUG
 872         if (!alreadyseen)
 873             TRACE(("token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 874         else
 875             TRACE(("reread token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 876 #endif
 877         return (t);
 878 }
 879
 880
 881 /*
 882  * Read the next input token.
 883  * If the token is a word, we set backquotelist to the list of cmds in
 884  *      backquotes.  We set quoteflag to true if any part of the word was
 885  *      quoted.
 886  * If the token is TREDIR, then we set redirnode to a structure containing
 887  *      the redirection.
 888  * In all cases, the variable startlinno is set to the number of the line
 889  *      on which the token starts.
 890  *
 891  * [Change comment:  here documents and internal procedures]
 892  * [Readtoken shouldn't have any arguments.  Perhaps we should make the
 893  *  word parsing code into a separate routine.  In this case, readtoken
 894  *  doesn't need to have any internal procedures, but parseword does.
 895  *  We could also make parseoperator in essence the main routine, and
 896  *  have parseword (readtoken1?) handle both words and redirection.]
 897  */
 898
 899 #define RETURN(token)   return lasttoken = token
 900
 901 static int
 902 xxreadtoken(void)
 903 {
 904         int c;
 905
 906         if (tokpushback) {
 907                 tokpushback = 0;
 908                 return lasttoken;
 909         }
 910         if (needprompt) {
 911                 setprompt(2);
 912                 needprompt = 0;
 913         }
 914         startlinno = plinno;
 915         for (;;) {      /* until token or start of word found */
 916                 c = pgetc_macro();
 917                 switch (c) {
 918                 case ' ': case '\t':
 919                         continue;
 920                 case '#':
 921                         while ((c = pgetc()) != '\n' && c != PEOF);
 922                         pungetc();
 923                         continue;
 924                 case '\\':
 925                         if (pgetc() == '\n') {
 926                                 startlinno = ++plinno;
 927                                 if (doprompt)
 928                                         setprompt(2);
 929                                 else
 930                                         setprompt(0);
 931                                 continue;
 932                         }
 933                         pungetc();
 934                         /* FALLTHROUGH */
 935                 default:
 936                         return readtoken1(c, BASESYNTAX, (char *)NULL, 0);
 937                 case '\n':
 938                         plinno++;
 939                         needprompt = doprompt;
 940                         RETURN(TNL);
 941                 case PEOF:
 942                         RETURN(TEOF);
 943                 case '&':
 944                         if (pgetc_linecont() == '&')
 945                                 RETURN(TAND);
 946                         pungetc();
 947                         RETURN(TBACKGND);
 948                 case '|':
 949                         if (pgetc_linecont() == '|')
 950                                 RETURN(TOR);
 951                         pungetc();
 952                         RETURN(TPIPE);
 953                 case ';':
 954                         c = pgetc_linecont();
 955                         if (c == ';')
 956                                 RETURN(TENDCASE);
 957                         else if (c == '&')
 958                                 RETURN(TFALLTHRU);
 959                         pungetc();
 960                         RETURN(TSEMI);
 961                 case '(':
 962                         RETURN(TLP);
 963                 case ')':
 964                         RETURN(TRP);
 965                 }
 966         }
 967 #undef RETURN
 968 }
 969
 970
 971 #define MAXNEST_static 8
 972 struct tokenstate
 973 {
 974         const char *syntax; /* *SYNTAX */
 975         int parenlevel; /* levels of parentheses in arithmetic */
 976         enum tokenstate_category
 977         {
 978                 TSTATE_TOP,
 979                 TSTATE_VAR_OLD, /* ${var+-=?}, inherits dquotes */
 980                 TSTATE_VAR_NEW, /* other ${var...}, own dquote state */
 981                 TSTATE_ARITH
 982         } category;
 983 };
 984
 985
 986 /*
 987  * Check to see whether we are at the end of the here document.  When this
 988  * is called, c is set to the first character of the next input line.  If
 989  * we are at the end of the here document, this routine sets the c to PEOF.
 990  * The new value of c is returned.
 991  */
 992
 993 static int
 994 checkend(int c, const char *eofmark, int striptabs)
 995 {
 996         if (striptabs) {
 997                 while (c == '\t')
 998                         c = pgetc();
 999         }
1000         if (c == *eofmark) {
1001                 int c2;
1002                 const char *q;
1003
1004                 for (q = eofmark + 1; c2 = pgetc(), *q != '\0' && c2 == *q; q++)
1005                         ;
1006                 if ((c2 == PEOF || c2 == '\n') && *q == '\0') {
1007                         c = PEOF;
1008                         if (c2 == '\n') {
1009                                 plinno++;
1010                                 needprompt = doprompt;
1011                         }
1012                 } else {
1013                         pungetc();
1014                         pushstring(eofmark + 1, q - (eofmark + 1), NULL);
1015                 }
1016         } else if (c == '\n' && *eofmark == '\0') {
1017                 c = PEOF;
1018                 plinno++;
1019                 needprompt = doprompt;
1020         }
1021         return (c);
1022 }
1023
1024
1025 /*
1026  * Parse a redirection operator.  The variable "out" points to a string
1027  * specifying the fd to be redirected.  The variable "c" contains the
1028  * first character of the redirection operator.
1029  */
1030
1031 static void
1032 parseredir(char *out, int c)
1033 {
1034         char fd = *out;
1035         union node *np;
1036
1037         np = (union node *)stalloc(sizeof (struct nfile));
1038         if (c == '>') {
1039                 np->nfile.fd = 1;
1040                 c = pgetc_linecont();
1041                 if (c == '>')
1042                         np->type = NAPPEND;
1043                 else if (c == '&')
1044                         np->type = NTOFD;
1045                 else if (c == '|')
1046                         np->type = NCLOBBER;
1047                 else {
1048                         np->type = NTO;
1049                         pungetc();
1050                 }
1051         } else {        /* c == '<' */
1052                 np->nfile.fd = 0;
1053                 c = pgetc_linecont();
1054                 if (c == '<') {
1055                         if (sizeof (struct nfile) != sizeof (struct nhere)) {
1056                                 np = (union node *)stalloc(sizeof (struct nhere));
1057                                 np->nfile.fd = 0;
1058                         }
1059                         np->type = NHERE;
1060                         heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
1061                         heredoc->here = np;
1062                         if ((c = pgetc_linecont()) == '-') {
1063                                 heredoc->striptabs = 1;
1064                         } else {
1065                                 heredoc->striptabs = 0;
1066                                 pungetc();
1067                         }
1068                 } else if (c == '&')
1069                         np->type = NFROMFD;
1070                 else if (c == '>')
1071                         np->type = NFROMTO;
1072                 else {
1073                         np->type = NFROM;
1074                         pungetc();
1075                 }
1076         }
1077         if (fd != '\0')
1078                 np->nfile.fd = digit_val(fd);
1079         redirnode = np;
1080 }
1081
1082 /*
1083  * Called to parse command substitutions.
1084  */
1085
1086 static char *
1087 parsebackq(char *out, struct nodelist **pbqlist,
1088                 int oldstyle, int dblquote, int quoted)
1089 {
1090         struct nodelist **nlpp;
1091         union node *n;
1092         char *volatile str;
1093         struct jmploc jmploc;
1094         struct jmploc *const savehandler = handler;
1095         size_t savelen;
1096         int saveprompt;
1097         const int bq_startlinno = plinno;
1098         char *volatile ostr = NULL;
1099         struct parsefile *const savetopfile = getcurrentfile();
1100         struct heredoc *const saveheredoclist = heredoclist;
1101         struct heredoc *here;
1102
1103         str = NULL;
1104         if (setjmp(jmploc.loc)) {
1105                 popfilesupto(savetopfile);
1106                 if (str)
1107                         ckfree(str);
1108                 if (ostr)
1109                         ckfree(ostr);
1110                 heredoclist = saveheredoclist;
1111                 handler = savehandler;
1112                 if (exception == EXERROR) {
1113                         startlinno = bq_startlinno;
1114                         synerror("Error in command substitution");
1115                 }
1116                 longjmp(handler->loc, 1);
1117         }
1118         INTOFF;
1119         savelen = out - stackblock();
1120         if (savelen > 0) {
1121                 str = ckmalloc(savelen);
1122                 memcpy(str, stackblock(), savelen);
1123         }
1124         handler = &jmploc;
1125         heredoclist = NULL;
1126         INTON;
1127         if (oldstyle) {
1128                 /* We must read until the closing backquote, giving special
1129                    treatment to some slashes, and then push the string and
1130                    reread it as input, interpreting it normally.  */
1131                 char *oout;
1132                 int c;
1133                 int olen;
1134
1135
1136                 STARTSTACKSTR(oout);
1137                 for (;;) {
1138                         if (needprompt) {
1139                                 setprompt(2);
1140                                 needprompt = 0;
1141                         }
1142                         CHECKSTRSPACE(2, oout);
1143                         c = pgetc_linecont();
1144                         if (c == '`')
1145                                 break;
1146                         switch (c) {
1147                         case '\\':
1148                                 c = pgetc();
1149                                 if (c != '\\' && c != '`' && c != '$'
1150                                     && (!dblquote || c != '"'))
1151                                         USTPUTC('\\', oout);
1152                                 break;
1153
1154                         case '\n':
1155                                 plinno++;
1156                                 needprompt = doprompt;
1157                                 break;
1158
1159                         case PEOF:
1160                                 startlinno = plinno;
1161                                 synerror("EOF in backquote substitution");
1162                                 break;
1163
1164                         default:
1165                                 break;
1166                         }
1167                         USTPUTC(c, oout);
1168                 }
1169                 USTPUTC('\0', oout);
1170                 olen = oout - stackblock();
1171                 INTOFF;
1172                 ostr = ckmalloc(olen);
1173                 memcpy(ostr, stackblock(), olen);
1174                 setinputstring(ostr, 1);
1175                 INTON;
1176         }
1177         nlpp = pbqlist;
1178         while (*nlpp)
1179                 nlpp = &(*nlpp)->next;
1180         *nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
1181         (*nlpp)->next = NULL;
1182
1183         if (oldstyle) {
1184                 saveprompt = doprompt;
1185                 doprompt = 0;
1186         }
1187
1188         n = list(0);
1189
1190         if (oldstyle) {
1191                 if (peektoken() != TEOF)
1192                         synexpect(-1);
1193                 doprompt = saveprompt;
1194         } else
1195                 consumetoken(TRP);
1196
1197         (*nlpp)->n = n;
1198         if (oldstyle) {
1199                 /*
1200                  * Start reading from old file again, ignoring any pushed back
1201                  * tokens left from the backquote parsing
1202                  */
1203                 popfile();
1204                 tokpushback = 0;
1205         }
1206         STARTSTACKSTR(out);
1207         CHECKSTRSPACE(savelen + 1, out);
1208         INTOFF;
1209         if (str) {
1210                 memcpy(out, str, savelen);
1211                 STADJUST(savelen, out);
1212                 ckfree(str);
1213                 str = NULL;
1214         }
1215         if (ostr) {
1216                 ckfree(ostr);
1217                 ostr = NULL;
1218         }
1219         here = saveheredoclist;
1220         if (here != NULL) {
1221                 while (here->next != NULL)
1222                         here = here->next;
1223                 here->next = heredoclist;
1224                 heredoclist = saveheredoclist;
1225         }
1226         handler = savehandler;
1227         INTON;
1228         if (quoted)
1229                 USTPUTC(CTLBACKQ | CTLQUOTE, out);
1230         else
1231                 USTPUTC(CTLBACKQ, out);
1232         return out;
1233 }
1234
1235
1236 /*
1237  * Called to parse a backslash escape sequence inside $'...'.
1238  * The backslash has already been read.
1239  */
1240 static char *
1241 readcstyleesc(char *out)
1242 {
1243         int c, vc, i, n;
1244         unsigned int v;
1245
1246         c = pgetc();
1247         switch (c) {
1248         case '\0':
1249                 synerror("Unterminated quoted string");
1250         case '\n':
1251                 plinno++;
1252                 if (doprompt)
1253                         setprompt(2);
1254                 else
1255                         setprompt(0);
1256                 return out;
1257         case '\\':
1258         case '\'':
1259         case '"':
1260                 v = c;
1261                 break;
1262         case 'a': v = '\a'; break;
1263         case 'b': v = '\b'; break;
1264         case 'e': v = '\033'; break;
1265         case 'f': v = '\f'; break;
1266         case 'n': v = '\n'; break;
1267         case 'r': v = '\r'; break;
1268         case 't': v = '\t'; break;
1269         case 'v': v = '\v'; break;
1270         case 'x':
1271                   v = 0;
1272                   for (;;) {
1273                           c = pgetc();
1274                           if (c >= '0' && c <= '9')
1275                                   v = (v << 4) + c - '0';
1276                           else if (c >= 'A' && c <= 'F')
1277                                   v = (v << 4) + c - 'A' + 10;
1278                           else if (c >= 'a' && c <= 'f')
1279                                   v = (v << 4) + c - 'a' + 10;
1280                           else
1281                                   break;
1282                   }
1283                   pungetc();
1284                   break;
1285         case '0': case '1': case '2': case '3':
1286         case '4': case '5': case '6': case '7':
1287                   v = c - '0';
1288                   c = pgetc();
1289                   if (c >= '0' && c <= '7') {
1290                           v <<= 3;
1291                           v += c - '0';
1292                           c = pgetc();
1293                           if (c >= '0' && c <= '7') {
1294                                   v <<= 3;
1295                                   v += c - '0';
1296                           } else
1297                                   pungetc();
1298                   } else
1299                           pungetc();
1300                   break;
1301         case 'c':
1302                   c = pgetc();
1303                   if (c < 0x3f || c > 0x7a || c == 0x60)
1304                           synerror("Bad escape sequence");
1305                   if (c == '\\' && pgetc() != '\\')
1306                           synerror("Bad escape sequence");
1307                   if (c == '?')
1308                           v = 127;
1309                   else
1310                           v = c & 0x1f;
1311                   break;
1312         case 'u':
1313         case 'U':
1314                   n = c == 'U' ? 8 : 4;
1315                   v = 0;
1316                   for (i = 0; i < n; i++) {
1317                           c = pgetc();
1318                           if (c >= '0' && c <= '9')
1319                                   v = (v << 4) + c - '0';
1320                           else if (c >= 'A' && c <= 'F')
1321                                   v = (v << 4) + c - 'A' + 10;
1322                           else if (c >= 'a' && c <= 'f')
1323                                   v = (v << 4) + c - 'a' + 10;
1324                           else
1325                                   synerror("Bad escape sequence");
1326                   }
1327                   if (v == 0 || (v >= 0xd800 && v <= 0xdfff))
1328                           synerror("Bad escape sequence");
1329                   /* We really need iconv here. */
1330                   if (initial_localeisutf8 && v > 127) {
1331                           CHECKSTRSPACE(4, out);
1332                           /*
1333                            * We cannot use wctomb() as the locale may have
1334                            * changed.
1335                            */
1336                           if (v <= 0x7ff) {
1337                                   USTPUTC(0xc0 | v >> 6, out);
1338                                   USTPUTC(0x80 | (v & 0x3f), out);
1339                                   return out;
1340                           } else if (v <= 0xffff) {
1341                                   USTPUTC(0xe0 | v >> 12, out);
1342                                   USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
1343                                   USTPUTC(0x80 | (v & 0x3f), out);
1344                                   return out;
1345                           } else if (v <= 0x10ffff) {
1346                                   USTPUTC(0xf0 | v >> 18, out);
1347                                   USTPUTC(0x80 | ((v >> 12) & 0x3f), out);
1348                                   USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
1349                                   USTPUTC(0x80 | (v & 0x3f), out);
1350                                   return out;
1351                           }
1352                   }
1353                   if (v > 127)
1354                           v = '?';
1355                   break;
1356         default:
1357                   synerror("Bad escape sequence");
1358         }
1359         vc = (char)v;
1360         /*
1361          * We can't handle NUL bytes.
1362          * POSIX says we should skip till the closing quote.
1363          */
1364         if (vc == '\0') {
1365                 while ((c = pgetc()) != '\'') {
1366                         if (c == '\\')
1367                                 c = pgetc();
1368                         if (c == PEOF)
1369                                 synerror("Unterminated quoted string");
1370                         if (c == '\n') {
1371                                 plinno++;
1372                                 if (doprompt)
1373                                         setprompt(2);
1374                                 else
1375                                         setprompt(0);
1376                         }
1377                 }
1378                 pungetc();
1379                 return out;
1380         }
1381         if (SQSYNTAX[vc] == CCTL)
1382                 USTPUTC(CTLESC, out);
1383         USTPUTC(vc, out);
1384         return out;
1385 }
1386
1387
1388 /*
1389  * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
1390  * is not NULL, read a here document.  In the latter case, eofmark is the
1391  * word which marks the end of the document and striptabs is true if
1392  * leading tabs should be stripped from the document.  The argument firstc
1393  * is the first character of the input token or document.
1394  *
1395  * Because C does not have internal subroutines, I have simulated them
1396  * using goto's to implement the subroutine linkage.  The following macros
1397  * will run code that appears at the end of readtoken1.
1398  */
1399
1400 #define PARSESUB()      {goto parsesub; parsesub_return:;}
1401 #define PARSEARITH()    {goto parsearith; parsearith_return:;}
1402
1403 static int
1404 readtoken1(int firstc, char const *initialsyntax, const char *eofmark,
1405     int striptabs)
1406 {
1407         int c = firstc;
1408         char *out;
1409         int len;
1410         struct nodelist *bqlist;
1411         int quotef;
1412         int newvarnest;
1413         int level;
1414         int synentry;
1415         struct tokenstate state_static[MAXNEST_static];
1416         int maxnest = MAXNEST_static;
1417         struct tokenstate *state = state_static;
1418         int sqiscstyle = 0;
1419
1420         startlinno = plinno;
1421         quotef = 0;
1422         bqlist = NULL;
1423         newvarnest = 0;
1424         level = 0;
1425         state[level].syntax = initialsyntax;
1426         state[level].parenlevel = 0;
1427         state[level].category = TSTATE_TOP;
1428
1429         STARTSTACKSTR(out);
1430         loop: { /* for each line, until end of word */
1431                 if (eofmark && eofmark != NOEOFMARK)
1432                         /* set c to PEOF if at end of here document */
1433                         c = checkend(c, eofmark, striptabs);
1434                 for (;;) {      /* until end of line or end of word */
1435                         CHECKSTRSPACE(4, out);  /* permit 4 calls to USTPUTC */
1436
1437                         synentry = state[level].syntax[c];
1438
1439                         switch(synentry) {
1440                         case CNL:       /* '\n' */
1441                                 if (level == 0)
1442                                         goto endword;   /* exit outer loop */
1443                                 /* FALLTHROUGH */
1444                         case CQNL:
1445                                 USTPUTC(c, out);
1446                                 plinno++;
1447                                 if (doprompt)
1448                                         setprompt(2);
1449                                 else
1450                                         setprompt(0);
1451                                 c = pgetc();
1452                                 goto loop;              /* continue outer loop */
1453                         case CSBACK:
1454                                 if (sqiscstyle) {
1455                                         out = readcstyleesc(out);
1456                                         break;
1457                                 }
1458                                 /* FALLTHROUGH */
1459                         case CWORD:
1460                                 USTPUTC(c, out);
1461                                 break;
1462                         case CCTL:
1463                                 if (eofmark == NULL || initialsyntax != SQSYNTAX)
1464                                         USTPUTC(CTLESC, out);
1465                                 USTPUTC(c, out);
1466                                 break;
1467                         case CBACK:     /* backslash */
1468                                 c = pgetc();
1469                                 if (c == PEOF) {
1470                                         USTPUTC('\\', out);
1471                                         pungetc();
1472                                 } else if (c == '\n') {
1473                                         plinno++;
1474                                         if (doprompt)
1475                                                 setprompt(2);
1476                                         else
1477                                                 setprompt(0);
1478                                 } else {
1479                                         if (state[level].syntax == DQSYNTAX &&
1480                                             c != '\\' && c != '`' && c != '$' &&
1481                                             (c != '"' || (eofmark != NULL &&
1482                                                 newvarnest == 0)) &&
1483                                             (c != '}' || state[level].category != TSTATE_VAR_OLD))
1484                                                 USTPUTC('\\', out);
1485                                         if ((eofmark == NULL ||
1486                                             newvarnest > 0) &&
1487                                             state[level].syntax == BASESYNTAX)
1488                                                 USTPUTC(CTLQUOTEMARK, out);
1489                                         if (SQSYNTAX[c] == CCTL)
1490                                                 USTPUTC(CTLESC, out);
1491                                         USTPUTC(c, out);
1492                                         if ((eofmark == NULL ||
1493                                             newvarnest > 0) &&
1494                                             state[level].syntax == BASESYNTAX &&
1495                                             state[level].category == TSTATE_VAR_OLD)
1496                                                 USTPUTC(CTLQUOTEEND, out);
1497                                         quotef++;
1498                                 }
1499                                 break;
1500                         case CSQUOTE:
1501                                 USTPUTC(CTLQUOTEMARK, out);
1502                                 state[level].syntax = SQSYNTAX;
1503                                 sqiscstyle = 0;
1504                                 break;
1505                         case CDQUOTE:
1506                                 USTPUTC(CTLQUOTEMARK, out);
1507                                 state[level].syntax = DQSYNTAX;
1508                                 break;
1509                         case CENDQUOTE:
1510                                 if (eofmark != NULL && newvarnest == 0)
1511                                         USTPUTC(c, out);
1512                                 else {
1513                                         if (state[level].category == TSTATE_VAR_OLD)
1514                                                 USTPUTC(CTLQUOTEEND, out);
1515                                         state[level].syntax = BASESYNTAX;
1516                                         quotef++;
1517                                 }
1518                                 break;
1519                         case CVAR:      /* '$' */
1520                                 PARSESUB();             /* parse substitution */
1521                                 break;
1522                         case CENDVAR:   /* '}' */
1523                                 if (level > 0 &&
1524                                     ((state[level].category == TSTATE_VAR_OLD &&
1525                                       state[level].syntax ==
1526                                       state[level - 1].syntax) ||
1527                                     (state[level].category == TSTATE_VAR_NEW &&
1528                                      state[level].syntax == BASESYNTAX))) {
1529                                         if (state[level].category == TSTATE_VAR_NEW)
1530                                                 newvarnest--;
1531                                         level--;
1532                                         USTPUTC(CTLENDVAR, out);
1533                                 } else {
1534                                         USTPUTC(c, out);
1535                                 }
1536                                 break;
1537                         case CLP:       /* '(' in arithmetic */
1538                                 state[level].parenlevel++;
1539                                 USTPUTC(c, out);
1540                                 break;
1541                         case CRP:       /* ')' in arithmetic */
1542                                 if (state[level].parenlevel > 0) {
1543                                         USTPUTC(c, out);
1544                                         --state[level].parenlevel;
1545                                 } else {
1546                                         if (pgetc_linecont() == ')') {
1547                                                 if (level > 0 &&
1548                                                     state[level].category == TSTATE_ARITH) {
1549                                                         level--;
1550                                                         USTPUTC(CTLENDARI, out);
1551                                                 } else
1552                                                         USTPUTC(')', out);
1553                                         } else {
1554                                                 /*
1555                                                  * unbalanced parens
1556                                                  *  (don't 2nd guess - no error)
1557                                                  */
1558                                                 pungetc();
1559                                                 USTPUTC(')', out);
1560                                         }
1561                                 }
1562                                 break;
1563                         case CBQUOTE:   /* '`' */
1564                                 out = parsebackq(out, &bqlist, 1,
1565                                     state[level].syntax == DQSYNTAX &&
1566                                     (eofmark == NULL || newvarnest > 0),
1567                                     state[level].syntax == DQSYNTAX || state[level].syntax == ARISYNTAX);
1568                                 break;
1569                         case CEOF:
1570                                 goto endword;           /* exit outer loop */
1571                         case CIGN:
1572                                 break;
1573                         default:
1574                                 if (level == 0)
1575                                         goto endword;   /* exit outer loop */
1576                                 USTPUTC(c, out);
1577                         }
1578                         c = pgetc_macro();
1579                 }
1580         }
1581 endword:
1582         if (state[level].syntax == ARISYNTAX)
1583                 synerror("Missing '))'");
1584         if (state[level].syntax != BASESYNTAX && eofmark == NULL)
1585                 synerror("Unterminated quoted string");
1586         if (state[level].category == TSTATE_VAR_OLD ||
1587             state[level].category == TSTATE_VAR_NEW) {
1588                 startlinno = plinno;
1589                 synerror("Missing '}'");
1590         }
1591         if (state != state_static)
1592                 parser_temp_free_upto(state);
1593         USTPUTC('\0', out);
1594         len = out - stackblock();
1595         out = stackblock();
1596         if (eofmark == NULL) {
1597                 if ((c == '>' || c == '<')
1598                  && quotef == 0
1599                  && len <= 2
1600                  && (*out == '\0' || is_digit(*out))) {
1601                         parseredir(out, c);
1602                         return lasttoken = TREDIR;
1603                 } else {
1604                         pungetc();
1605                 }
1606         }
1607         quoteflag = quotef;
1608         backquotelist = bqlist;
1609         grabstackblock(len);
1610         wordtext = out;
1611         return lasttoken = TWORD;
1612 /* end of readtoken routine */
1613
1614
1615 /*
1616  * Parse a substitution.  At this point, we have read the dollar sign
1617  * and nothing else.
1618  */
1619
1620 parsesub: {
1621         int subtype;
1622         int typeloc;
1623         int flags;
1624         char *p;
1625         static const char types[] = "}-+?=";
1626         int linno;
1627         int length;
1628         int c1;
1629
1630         c = pgetc_linecont();
1631         if (c == '(') { /* $(command) or $((arith)) */
1632                 if (pgetc_linecont() == '(') {
1633                         PARSEARITH();
1634                 } else {
1635                         pungetc();
1636                         out = parsebackq(out, &bqlist, 0,
1637                             state[level].syntax == DQSYNTAX &&
1638                             (eofmark == NULL || newvarnest > 0),
1639                             state[level].syntax == DQSYNTAX ||
1640                             state[level].syntax == ARISYNTAX);
1641                 }
1642         } else if (c == '{' || is_name(c) || is_special(c)) {
1643                 USTPUTC(CTLVAR, out);
1644                 typeloc = out - stackblock();
1645                 USTPUTC(VSNORMAL, out);
1646                 subtype = VSNORMAL;
1647                 flags = 0;
1648                 if (c == '{') {
1649                         c = pgetc_linecont();
1650                         subtype = 0;
1651                 }
1652 varname:
1653                 if (!is_eof(c) && is_name(c)) {
1654                         length = 0;
1655                         do {
1656                                 STPUTC(c, out);
1657                                 c = pgetc_linecont();
1658                                 length++;
1659                         } while (!is_eof(c) && is_in_name(c));
1660                         if (length == 6 &&
1661                             strncmp(out - length, "LINENO", length) == 0) {
1662                                 /* Replace the variable name with the
1663                                  * current line number. */
1664                                 STADJUST(-6, out);
1665                                 CHECKSTRSPACE(11, out);
1666                                 linno = plinno;
1667                                 if (funclinno != 0)
1668                                         linno -= funclinno - 1;
1669                                 length = snprintf(out, 11, "%d", linno);
1670                                 if (length > 10)
1671                                         length = 10;
1672                                 out += length;
1673                                 flags |= VSLINENO;
1674                         }
1675                 } else if (is_digit(c)) {
1676                         if (subtype != VSNORMAL) {
1677                                 do {
1678                                         STPUTC(c, out);
1679                                         c = pgetc_linecont();
1680                                 } while (is_digit(c));
1681                         } else {
1682                                 USTPUTC(c, out);
1683                                 c = pgetc_linecont();
1684                         }
1685                 } else if (is_special(c)) {
1686                         c1 = c;
1687                         c = pgetc_linecont();
1688                         if (subtype == 0 && c1 == '#') {
1689                                 subtype = VSLENGTH;
1690                                 if (strchr(types, c) == NULL && c != ':' &&
1691                                     c != '#' && c != '%')
1692                                         goto varname;
1693                                 c1 = c;
1694                                 c = pgetc_linecont();
1695                                 if (c1 != '}' && c == '}') {
1696                                         pungetc();
1697                                         c = c1;
1698                                         goto varname;
1699                                 }
1700                                 pungetc();
1701                                 c = c1;
1702                                 c1 = '#';
1703                                 subtype = 0;
1704                         }
1705                         USTPUTC(c1, out);
1706                 } else {
1707                         subtype = VSERROR;
1708                         if (c == '}')
1709                                 pungetc();
1710                         else if (c == '\n' || c == PEOF)
1711                                 synerror("Unexpected end of line in substitution");
1712                         else if (BASESYNTAX[c] != CCTL)
1713                                 USTPUTC(c, out);
1714                 }
1715                 if (subtype == 0) {
1716                         switch (c) {
1717                         case ':':
1718                                 flags |= VSNUL;
1719                                 c = pgetc_linecont();
1720                                 /*FALLTHROUGH*/
1721                         default:
1722                                 p = strchr(types, c);
1723                                 if (p == NULL) {
1724                                         if (c == '\n' || c == PEOF)
1725                                                 synerror("Unexpected end of line in substitution");
1726                                         if (flags == VSNUL)
1727                                                 STPUTC(':', out);
1728                                         if (BASESYNTAX[c] != CCTL)
1729                                                 STPUTC(c, out);
1730                                         subtype = VSERROR;
1731                                 } else
1732                                         subtype = p - types + VSNORMAL;
1733                                 break;
1734                         case '%':
1735                         case '#':
1736                                 {
1737                                         int cc = c;
1738                                         subtype = c == '#' ? VSTRIMLEFT :
1739                                                              VSTRIMRIGHT;
1740                                         c = pgetc_linecont();
1741                                         if (c == cc)
1742                                                 subtype++;
1743                                         else
1744                                                 pungetc();
1745                                         break;
1746                                 }
1747                         }
1748                 } else if (subtype != VSERROR) {
1749                         if (subtype == VSLENGTH && c != '}')
1750                                 subtype = VSERROR;
1751                         pungetc();
1752                 }
1753                 STPUTC('=', out);
1754                 if (state[level].syntax == DQSYNTAX ||
1755                     state[level].syntax == ARISYNTAX)
1756                         flags |= VSQUOTE;
1757                 *(stackblock() + typeloc) = subtype | flags;
1758                 if (subtype != VSNORMAL) {
1759                         if (level + 1 >= maxnest) {
1760                                 maxnest *= 2;
1761                                 if (state == state_static) {
1762                                         state = parser_temp_alloc(
1763                                             maxnest * sizeof(*state));
1764                                         memcpy(state, state_static,
1765                                             MAXNEST_static * sizeof(*state));
1766                                 } else
1767                                         state = parser_temp_realloc(state,
1768                                             maxnest * sizeof(*state));
1769                         }
1770                         level++;
1771                         state[level].parenlevel = 0;
1772                         if (subtype == VSMINUS || subtype == VSPLUS ||
1773                             subtype == VSQUESTION || subtype == VSASSIGN) {
1774                                 /*
1775                                  * For operators that were in the Bourne shell,
1776                                  * inherit the double-quote state.
1777                                  */
1778                                 state[level].syntax = state[level - 1].syntax;
1779                                 state[level].category = TSTATE_VAR_OLD;
1780                         } else {
1781                                 /*
1782                                  * The other operators take a pattern,
1783                                  * so go to BASESYNTAX.
1784                                  * Also, ' and " are now special, even
1785                                  * in here documents.
1786                                  */
1787                                 state[level].syntax = BASESYNTAX;
1788                                 state[level].category = TSTATE_VAR_NEW;
1789                                 newvarnest++;
1790                         }
1791                 }
1792         } else if (c == '\'' && state[level].syntax == BASESYNTAX) {
1793                 /* $'cstylequotes' */
1794                 USTPUTC(CTLQUOTEMARK, out);
1795                 state[level].syntax = SQSYNTAX;
1796                 sqiscstyle = 1;
1797         } else {
1798                 USTPUTC('$', out);
1799                 pungetc();
1800         }
1801         goto parsesub_return;
1802 }
1803
1804
1805 /*
1806  * Parse an arithmetic expansion (indicate start of one and set state)
1807  */
1808 parsearith: {
1809
1810         if (level + 1 >= maxnest) {
1811                 maxnest *= 2;
1812                 if (state == state_static) {
1813                         state = parser_temp_alloc(
1814                             maxnest * sizeof(*state));
1815                         memcpy(state, state_static,
1816                             MAXNEST_static * sizeof(*state));
1817                 } else
1818                         state = parser_temp_realloc(state,
1819                             maxnest * sizeof(*state));
1820         }
1821         level++;
1822         state[level].syntax = ARISYNTAX;
1823         state[level].parenlevel = 0;
1824         state[level].category = TSTATE_ARITH;
1825         USTPUTC(CTLARI, out);
1826         if (state[level - 1].syntax == DQSYNTAX)
1827                 USTPUTC('"',out);
1828         else
1829                 USTPUTC(' ',out);
1830         goto parsearith_return;
1831 }
1832
1833 } /* end of readtoken */
1834
1835
1836 /*
1837  * Returns true if the text contains nothing to expand (no dollar signs
1838  * or backquotes).
1839  */
1840
1841 static int
1842 noexpand(char *text)
1843 {
1844         char *p;
1845         char c;
1846
1847         p = text;
1848         while ((c = *p++) != '\0') {
1849                 if ( c == CTLQUOTEMARK)
1850                         continue;
1851                 if (c == CTLESC)
1852                         p++;
1853                 else if (BASESYNTAX[(int)c] == CCTL)
1854                         return 0;
1855         }
1856         return 1;
1857 }
1858
1859
1860 /*
1861  * Return true if the argument is a legal variable name (a letter or
1862  * underscore followed by zero or more letters, underscores, and digits).
1863  */
1864
1865 int
1866 goodname(const char *name)
1867 {
1868         const char *p;
1869
1870         p = name;
1871         if (! is_name(*p))
1872                 return 0;
1873         while (*++p) {
1874                 if (! is_in_name(*p))
1875                         return 0;
1876         }
1877         return 1;
1878 }
1879
1880
1881 int
1882 isassignment(const char *p)
1883 {
1884         if (!is_name(*p))
1885                 return 0;
1886         p++;
1887         for (;;) {
1888                 if (*p == '=')
1889                         return 1;
1890                 else if (!is_in_name(*p))
1891                         return 0;
1892                 p++;
1893         }
1894 }
1895
1896
1897 static void
1898 consumetoken(int token)
1899 {
1900         if (readtoken() != token)
1901                 synexpect(token);
1902 }
1903
1904
1905 /*
1906  * Called when an unexpected token is read during the parse.  The argument
1907  * is the token that is expected, or -1 if more than one type of token can
1908  * occur at this point.
1909  */
1910
1911 static void
1912 synexpect(int token)
1913 {
1914         char msg[64];
1915
1916         if (token >= 0) {
1917                 fmtstr(msg, 64, "%s unexpected (expecting %s)",
1918                         tokname[lasttoken], tokname[token]);
1919         } else {
1920                 fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
1921         }
1922         synerror(msg);
1923 }
1924
1925
1926 static void
1927 synerror(const char *msg)
1928 {
1929         if (commandname)
1930                 outfmt(out2, "%s: %d: ", commandname, startlinno);
1931         else if (arg0)
1932                 outfmt(out2, "%s: ", arg0);
1933         outfmt(out2, "Syntax error: %s\n", msg);
1934         error((char *)NULL);
1935 }
1936
1937 static void
1938 setprompt(int which)
1939 {
1940         whichprompt = which;
1941         if (which == 0)
1942                 return;
1943
1944 #ifndef NO_HISTORY
1945         if (!el)
1946 #endif
1947         {
1948                 out2str(getprompt(NULL));
1949                 flushout(out2);
1950         }
1951 }
1952
1953 static int
1954 pgetc_linecont(void)
1955 {
1956         int c;
1957
1958         while ((c = pgetc_macro()) == '\\') {
1959                 c = pgetc();
1960                 if (c == '\n') {
1961                         plinno++;
1962                         if (doprompt)
1963                                 setprompt(2);
1964                         else
1965                                 setprompt(0);
1966                 } else {
1967                         pungetc();
1968                         /* Allow the backslash to be pushed back. */
1969                         pushstring("\\", 1, NULL);
1970                         return (pgetc());
1971                 }
1972         }
1973         return (c);
1974 }
1975
1976
1977 static struct passwd *
1978 getpwlogin(void)
1979 {
1980         const char *login;
1981
1982         login = getlogin();
1983         if (login == NULL)
1984                 return (NULL);
1985
1986         return (getpwnam(login));
1987 }
1988
1989
1990 static void
1991 getusername(char *name, size_t namelen)
1992 {
1993         static char cached_name[MAXLOGNAME];
1994         struct passwd *pw;
1995         uid_t euid;
1996
1997         if (cached_name[0] == '\0') {
1998                 euid = geteuid();
1999
2000                 /*
2001                  * Handle the case when there is more than one
2002                  * login with the same UID, or when the login
2003                  * returned by getlogin(2) does no longer match
2004                  * the current UID.
2005                  */
2006                 pw = getpwlogin();
2007                 if (pw == NULL || pw->pw_uid != euid)
2008                         pw = getpwuid(euid);
2009
2010                 if (pw != NULL) {
2011                         strlcpy(cached_name, pw->pw_name,
2012                             sizeof(cached_name));
2013                 } else {
2014                         snprintf(cached_name, sizeof(cached_name),
2015                             "%u", euid);
2016                 }
2017         }
2018
2019         strlcpy(name, cached_name, namelen);
2020 }
2021
2022
2023 /*
2024  * called by editline -- any expansions to the prompt
2025  *    should be added here.
2026  */
2027 char *
2028 getprompt(void *unused __unused)
2029 {
2030         static char ps[PROMPTLEN];
2031         const char *fmt;
2032         const char *home;
2033         const char *pwd;
2034         size_t homelen;
2035         int i, trim;
2036         static char internal_error[] = "??";
2037
2038         /*
2039          * Select prompt format.
2040          */
2041         switch (whichprompt) {
2042         case 0:
2043                 fmt = "";
2044                 break;
2045         case 1:
2046                 fmt = ps1val();
2047                 break;
2048         case 2:
2049                 fmt = ps2val();
2050                 break;
2051         default:
2052                 return internal_error;
2053         }
2054
2055         /*
2056          * Format prompt string.
2057          */
2058         for (i = 0; (i < PROMPTLEN - 1) && (*fmt != '\0'); i++, fmt++)
2059                 if (*fmt == '\\')
2060                         switch (*++fmt) {
2061
2062                                 /*
2063                                  * Hostname.
2064                                  *
2065                                  * \h specifies just the local hostname,
2066                                  * \H specifies fully-qualified hostname.
2067                                  */
2068                         case 'h':
2069                         case 'H':
2070                                 ps[i] = '\0';
2071                                 gethostname(&ps[i], PROMPTLEN - i - 1);
2072                                 ps[PROMPTLEN - 1] = '\0';
2073                                 /* Skip to end of hostname. */
2074                                 trim = (*fmt == 'h') ? '.' : '\0';
2075                                 while ((ps[i] != '\0') && (ps[i] != trim))
2076                                         i++;
2077                                 --i;
2078                                 break;
2079
2080                                 /*
2081                                  * User name.
2082                                  */
2083                         case 'u':
2084                                 ps[i] = '\0';
2085                                 getusername(&ps[i], PROMPTLEN - i);
2086                                 /* Skip to end of username. */
2087                                 while (ps[i + 1] != '\0')
2088                                         i++;
2089                                 break;
2090
2091                                 /*
2092                                  * Working directory.
2093                                  *
2094                                  * \W specifies just the final component,
2095                                  * \w specifies the entire path.
2096                                  */
2097                         case 'W':
2098                         case 'w':
2099                                 pwd = lookupvar("PWD");
2100                                 if (pwd == NULL || *pwd == '\0')
2101                                         pwd = "?";
2102                                 if (*fmt == 'W' &&
2103                                     *pwd == '/' && pwd[1] != '\0')
2104                                         strlcpy(&ps[i], strrchr(pwd, '/') + 1,
2105                                             PROMPTLEN - i);
2106                                 else {
2107                                         home = lookupvar("HOME");
2108                                         if (home != NULL)
2109                                                 homelen = strlen(home);
2110                                         if (home != NULL &&
2111                                             strcmp(home, "/") != 0 &&
2112                                             strncmp(pwd, home, homelen) == 0 &&
2113                                             (pwd[homelen] == '/' ||
2114                                             pwd[homelen] == '\0')) {
2115                                                 strlcpy(&ps[i], "~",
2116                                                     PROMPTLEN - i);
2117                                                 strlcpy(&ps[i + 1],
2118                                                     pwd + homelen,
2119                                                     PROMPTLEN - i - 1);
2120                                         } else {
2121                                                 strlcpy(&ps[i], pwd, PROMPTLEN - i);
2122                                         }
2123                                 }
2124                                 /* Skip to end of path. */
2125                                 while (ps[i + 1] != '\0')
2126                                         i++;
2127                                 break;
2128
2129                                 /*
2130                                  * Superuser status.
2131                                  *
2132                                  * '$' for normal users, '#' for root.
2133                                  */
2134                         case '$':
2135                                 ps[i] = (geteuid() != 0) ? '$' : '#';
2136                                 break;
2137
2138                                 /*
2139                                  * A literal \.
2140                                  */
2141                         case '\\':
2142                                 ps[i] = '\\';
2143                                 break;
2144
2145                                 /*
2146                                  * Emit unrecognized formats verbatim.
2147                                  */
2148                         default:
2149                                 ps[i] = '\\';
2150                                 if (i < PROMPTLEN - 2)
2151                                         ps[++i] = *fmt;
2152                                 break;
2153                         }
2154                 else
2155                         ps[i] = *fmt;
2156         ps[i] = '\0';
2157         return (ps);
2158 }
2159
2160
2161 const char *
2162 expandstr(const char *ps)
2163 {
2164         union node n;
2165         struct jmploc jmploc;
2166         struct jmploc *const savehandler = handler;
2167         const int saveprompt = doprompt;
2168         struct parsefile *const savetopfile = getcurrentfile();
2169         struct parser_temp *const saveparser_temp = parser_temp;
2170         const char *result = NULL;
2171
2172         if (!setjmp(jmploc.loc)) {
2173                 handler = &jmploc;
2174                 parser_temp = NULL;
2175                 setinputstring(ps, 1);
2176                 doprompt = 0;
2177                 readtoken1(pgetc(), DQSYNTAX, NOEOFMARK, 0);
2178                 if (backquotelist != NULL)
2179                         error("Command substitution not allowed here");
2180
2181                 n.narg.type = NARG;
2182                 n.narg.next = NULL;
2183                 n.narg.text = wordtext;
2184                 n.narg.backquote = backquotelist;
2185
2186                 expandarg(&n, NULL, 0);
2187                 result = stackblock();
2188                 INTOFF;
2189         }
2190         handler = savehandler;
2191         doprompt = saveprompt;
2192         popfilesupto(savetopfile);
2193         if (parser_temp != saveparser_temp) {
2194                 parser_temp_free_all();
2195                 parser_temp = saveparser_temp;
2196         }
2197         if (result != NULL) {
2198                 INTON;
2199         } else if (exception == EXINT)
2200                 raise(SIGINT);
2201         return result;
2202 }