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