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/bin/sh/parser.c

https://bitbucket.org/freebsd/freebsd-head/
C | 2080 lines | 1844 code | 104 blank | 132 comment | 360 complexity | 5c3435391c19382f0f15de4322b344af MD5 | raw file
   1/*-
   2 * Copyright (c) 1991, 1993
   3 *	The Regents of the University of California.  All rights reserved.
   4 *
   5 * This code is derived from software contributed to Berkeley by
   6 * Kenneth Almquist.
   7 *
   8 * Redistribution and use in source and binary forms, with or without
   9 * modification, are permitted provided that the following conditions
  10 * are met:
  11 * 1. Redistributions of source code must retain the above copyright
  12 *    notice, this list of conditions and the following disclaimer.
  13 * 2. Redistributions in binary form must reproduce the above copyright
  14 *    notice, this list of conditions and the following disclaimer in the
  15 *    documentation and/or other materials provided with the distribution.
  16 * 4. Neither the name of the University nor the names of its contributors
  17 *    may be used to endorse or promote products derived from this software
  18 *    without specific prior written permission.
  19 *
  20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30 * SUCH DAMAGE.
  31 */
  32
  33#ifndef lint
  34#if 0
  35static char sccsid[] = "@(#)parser.c	8.7 (Berkeley) 5/16/95";
  36#endif
  37#endif /* not lint */
  38#include <sys/cdefs.h>
  39__FBSDID("$FreeBSD$");
  40
  41#include <stdlib.h>
  42#include <unistd.h>
  43#include <stdio.h>
  44
  45#include "shell.h"
  46#include "parser.h"
  47#include "nodes.h"
  48#include "expand.h"	/* defines rmescapes() */
  49#include "syntax.h"
  50#include "options.h"
  51#include "input.h"
  52#include "output.h"
  53#include "var.h"
  54#include "error.h"
  55#include "memalloc.h"
  56#include "mystring.h"
  57#include "alias.h"
  58#include "show.h"
  59#include "eval.h"
  60#include "exec.h"	/* to check for special builtins */
  61#ifndef NO_HISTORY
  62#include "myhistedit.h"
  63#endif
  64
  65/*
  66 * Shell command parser.
  67 */
  68
  69#define	EOFMARKLEN	79
  70#define	PROMPTLEN	128
  71
  72/* values of checkkwd variable */
  73#define CHKALIAS	0x1
  74#define CHKKWD		0x2
  75#define CHKNL		0x4
  76
  77/* values returned by readtoken */
  78#include "token.h"
  79
  80
  81
  82struct heredoc {
  83	struct heredoc *next;	/* next here document in list */
  84	union node *here;		/* redirection node */
  85	char *eofmark;		/* string indicating end of input */
  86	int striptabs;		/* if set, strip leading tabs */
  87};
  88
  89struct parser_temp {
  90	struct parser_temp *next;
  91	void *data;
  92};
  93
  94
  95static struct heredoc *heredoclist;	/* list of here documents to read */
  96static int doprompt;		/* if set, prompt the user */
  97static int needprompt;		/* true if interactive and at start of line */
  98static int lasttoken;		/* last token read */
  99MKINIT int tokpushback;		/* last token pushed back */
 100static char *wordtext;		/* text of last word returned by readtoken */
 101MKINIT int checkkwd;            /* 1 == check for kwds, 2 == also eat newlines */
 102static struct nodelist *backquotelist;
 103static union node *redirnode;
 104static struct heredoc *heredoc;
 105static int quoteflag;		/* set if (part of) last token was quoted */
 106static int startlinno;		/* line # where last token started */
 107static int funclinno;		/* line # where the current function started */
 108static struct parser_temp *parser_temp;
 109
 110
 111static union node *list(int, int);
 112static union node *andor(void);
 113static union node *pipeline(void);
 114static union node *command(void);
 115static union node *simplecmd(union node **, union node *);
 116static union node *makename(void);
 117static void parsefname(void);
 118static void parseheredoc(void);
 119static int peektoken(void);
 120static int readtoken(void);
 121static int xxreadtoken(void);
 122static int readtoken1(int, char const *, char *, int);
 123static int noexpand(char *);
 124static void synexpect(int) __dead2;
 125static void synerror(const char *) __dead2;
 126static void setprompt(int);
 127
 128
 129static void *
 130parser_temp_alloc(size_t len)
 131{
 132	struct parser_temp *t;
 133
 134	INTOFF;
 135	t = ckmalloc(sizeof(*t));
 136	t->data = NULL;
 137	t->next = parser_temp;
 138	parser_temp = t;
 139	t->data = ckmalloc(len);
 140	INTON;
 141	return t->data;
 142}
 143
 144
 145static void *
 146parser_temp_realloc(void *ptr, size_t len)
 147{
 148	struct parser_temp *t;
 149
 150	INTOFF;
 151	t = parser_temp;
 152	if (ptr != t->data)
 153		error("bug: parser_temp_realloc misused");
 154	t->data = ckrealloc(t->data, len);
 155	INTON;
 156	return t->data;
 157}
 158
 159
 160static void
 161parser_temp_free_upto(void *ptr)
 162{
 163	struct parser_temp *t;
 164	int done = 0;
 165
 166	INTOFF;
 167	while (parser_temp != NULL && !done) {
 168		t = parser_temp;
 169		parser_temp = t->next;
 170		done = t->data == ptr;
 171		ckfree(t->data);
 172		ckfree(t);
 173	}
 174	INTON;
 175	if (!done)
 176		error("bug: parser_temp_free_upto misused");
 177}
 178
 179
 180static void
 181parser_temp_free_all(void)
 182{
 183	struct parser_temp *t;
 184
 185	INTOFF;
 186	while (parser_temp != NULL) {
 187		t = parser_temp;
 188		parser_temp = t->next;
 189		ckfree(t->data);
 190		ckfree(t);
 191	}
 192	INTON;
 193}
 194
 195
 196/*
 197 * Read and parse a command.  Returns NEOF on end of file.  (NULL is a
 198 * valid parse tree indicating a blank line.)
 199 */
 200
 201union node *
 202parsecmd(int interact)
 203{
 204	int t;
 205
 206	/* This assumes the parser is not re-entered,
 207	 * which could happen if we add command substitution on PS1/PS2.
 208	 */
 209	parser_temp_free_all();
 210	heredoclist = NULL;
 211
 212	tokpushback = 0;
 213	doprompt = interact;
 214	if (doprompt)
 215		setprompt(1);
 216	else
 217		setprompt(0);
 218	needprompt = 0;
 219	t = readtoken();
 220	if (t == TEOF)
 221		return NEOF;
 222	if (t == TNL)
 223		return NULL;
 224	tokpushback++;
 225	return list(1, 1);
 226}
 227
 228
 229static union node *
 230list(int nlflag, int erflag)
 231{
 232	union node *ntop, *n1, *n2, *n3;
 233	int tok;
 234
 235	checkkwd = CHKNL | CHKKWD | CHKALIAS;
 236	if (!nlflag && !erflag && tokendlist[peektoken()])
 237		return NULL;
 238	ntop = n1 = NULL;
 239	for (;;) {
 240		n2 = andor();
 241		tok = readtoken();
 242		if (tok == TBACKGND) {
 243			if (n2->type == NPIPE) {
 244				n2->npipe.backgnd = 1;
 245			} else if (n2->type == NREDIR) {
 246				n2->type = NBACKGND;
 247			} else {
 248				n3 = (union node *)stalloc(sizeof (struct nredir));
 249				n3->type = NBACKGND;
 250				n3->nredir.n = n2;
 251				n3->nredir.redirect = NULL;
 252				n2 = n3;
 253			}
 254		}
 255		if (ntop == NULL)
 256			ntop = n2;
 257		else if (n1 == NULL) {
 258			n1 = (union node *)stalloc(sizeof (struct nbinary));
 259			n1->type = NSEMI;
 260			n1->nbinary.ch1 = ntop;
 261			n1->nbinary.ch2 = n2;
 262			ntop = n1;
 263		}
 264		else {
 265			n3 = (union node *)stalloc(sizeof (struct nbinary));
 266			n3->type = NSEMI;
 267			n3->nbinary.ch1 = n1->nbinary.ch2;
 268			n3->nbinary.ch2 = n2;
 269			n1->nbinary.ch2 = n3;
 270			n1 = n3;
 271		}
 272		switch (tok) {
 273		case TBACKGND:
 274		case TSEMI:
 275			tok = readtoken();
 276			/* FALLTHROUGH */
 277		case TNL:
 278			if (tok == TNL) {
 279				parseheredoc();
 280				if (nlflag)
 281					return ntop;
 282			} else if (tok == TEOF && nlflag) {
 283				parseheredoc();
 284				return ntop;
 285			} else {
 286				tokpushback++;
 287			}
 288			checkkwd = CHKNL | CHKKWD | CHKALIAS;
 289			if (!nlflag && !erflag && tokendlist[peektoken()])
 290				return ntop;
 291			break;
 292		case TEOF:
 293			if (heredoclist)
 294				parseheredoc();
 295			else
 296				pungetc();		/* push back EOF on input */
 297			return ntop;
 298		default:
 299			if (nlflag || erflag)
 300				synexpect(-1);
 301			tokpushback++;
 302			return ntop;
 303		}
 304	}
 305}
 306
 307
 308
 309static union node *
 310andor(void)
 311{
 312	union node *n1, *n2, *n3;
 313	int t;
 314
 315	n1 = pipeline();
 316	for (;;) {
 317		if ((t = readtoken()) == TAND) {
 318			t = NAND;
 319		} else if (t == TOR) {
 320			t = NOR;
 321		} else {
 322			tokpushback++;
 323			return n1;
 324		}
 325		n2 = pipeline();
 326		n3 = (union node *)stalloc(sizeof (struct nbinary));
 327		n3->type = t;
 328		n3->nbinary.ch1 = n1;
 329		n3->nbinary.ch2 = n2;
 330		n1 = n3;
 331	}
 332}
 333
 334
 335
 336static union node *
 337pipeline(void)
 338{
 339	union node *n1, *n2, *pipenode;
 340	struct nodelist *lp, *prev;
 341	int negate, t;
 342
 343	negate = 0;
 344	checkkwd = CHKNL | CHKKWD | CHKALIAS;
 345	TRACE(("pipeline: entered\n"));
 346	while (readtoken() == TNOT)
 347		negate = !negate;
 348	tokpushback++;
 349	n1 = command();
 350	if (readtoken() == TPIPE) {
 351		pipenode = (union node *)stalloc(sizeof (struct npipe));
 352		pipenode->type = NPIPE;
 353		pipenode->npipe.backgnd = 0;
 354		lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 355		pipenode->npipe.cmdlist = lp;
 356		lp->n = n1;
 357		do {
 358			prev = lp;
 359			lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
 360			checkkwd = CHKNL | CHKKWD | CHKALIAS;
 361			t = readtoken();
 362			tokpushback++;
 363			if (t == TNOT)
 364				lp->n = pipeline();
 365			else
 366				lp->n = command();
 367			prev->next = lp;
 368		} while (readtoken() == TPIPE);
 369		lp->next = NULL;
 370		n1 = pipenode;
 371	}
 372	tokpushback++;
 373	if (negate) {
 374		n2 = (union node *)stalloc(sizeof (struct nnot));
 375		n2->type = NNOT;
 376		n2->nnot.com = n1;
 377		return n2;
 378	} else
 379		return n1;
 380}
 381
 382
 383
 384static union node *
 385command(void)
 386{
 387	union node *n1, *n2;
 388	union node *ap, **app;
 389	union node *cp, **cpp;
 390	union node *redir, **rpp;
 391	int t;
 392	int is_subshell;
 393
 394	checkkwd = CHKNL | CHKKWD | CHKALIAS;
 395	is_subshell = 0;
 396	redir = NULL;
 397	n1 = NULL;
 398	rpp = &redir;
 399
 400	/* Check for redirection which may precede command */
 401	while (readtoken() == TREDIR) {
 402		*rpp = n2 = redirnode;
 403		rpp = &n2->nfile.next;
 404		parsefname();
 405	}
 406	tokpushback++;
 407
 408	switch (readtoken()) {
 409	case TIF:
 410		n1 = (union node *)stalloc(sizeof (struct nif));
 411		n1->type = NIF;
 412		if ((n1->nif.test = list(0, 0)) == NULL)
 413			synexpect(-1);
 414		if (readtoken() != TTHEN)
 415			synexpect(TTHEN);
 416		n1->nif.ifpart = list(0, 0);
 417		n2 = n1;
 418		while (readtoken() == TELIF) {
 419			n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
 420			n2 = n2->nif.elsepart;
 421			n2->type = NIF;
 422			if ((n2->nif.test = list(0, 0)) == NULL)
 423				synexpect(-1);
 424			if (readtoken() != TTHEN)
 425				synexpect(TTHEN);
 426			n2->nif.ifpart = list(0, 0);
 427		}
 428		if (lasttoken == TELSE)
 429			n2->nif.elsepart = list(0, 0);
 430		else {
 431			n2->nif.elsepart = NULL;
 432			tokpushback++;
 433		}
 434		if (readtoken() != TFI)
 435			synexpect(TFI);
 436		checkkwd = CHKKWD | CHKALIAS;
 437		break;
 438	case TWHILE:
 439	case TUNTIL: {
 440		int got;
 441		n1 = (union node *)stalloc(sizeof (struct nbinary));
 442		n1->type = (lasttoken == TWHILE)? NWHILE : NUNTIL;
 443		if ((n1->nbinary.ch1 = list(0, 0)) == NULL)
 444			synexpect(-1);
 445		if ((got=readtoken()) != TDO) {
 446TRACE(("expecting DO got %s %s\n", tokname[got], got == TWORD ? wordtext : ""));
 447			synexpect(TDO);
 448		}
 449		n1->nbinary.ch2 = list(0, 0);
 450		if (readtoken() != TDONE)
 451			synexpect(TDONE);
 452		checkkwd = CHKKWD | CHKALIAS;
 453		break;
 454	}
 455	case TFOR:
 456		if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
 457			synerror("Bad for loop variable");
 458		n1 = (union node *)stalloc(sizeof (struct nfor));
 459		n1->type = NFOR;
 460		n1->nfor.var = wordtext;
 461		while (readtoken() == TNL)
 462			;
 463		if (lasttoken == TWORD && ! quoteflag && equal(wordtext, "in")) {
 464			app = &ap;
 465			while (readtoken() == TWORD) {
 466				n2 = (union node *)stalloc(sizeof (struct narg));
 467				n2->type = NARG;
 468				n2->narg.text = wordtext;
 469				n2->narg.backquote = backquotelist;
 470				*app = n2;
 471				app = &n2->narg.next;
 472			}
 473			*app = NULL;
 474			n1->nfor.args = ap;
 475			if (lasttoken != TNL && lasttoken != TSEMI)
 476				synexpect(-1);
 477		} else {
 478			static char argvars[5] = {
 479				CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'
 480			};
 481			n2 = (union node *)stalloc(sizeof (struct narg));
 482			n2->type = NARG;
 483			n2->narg.text = argvars;
 484			n2->narg.backquote = NULL;
 485			n2->narg.next = NULL;
 486			n1->nfor.args = n2;
 487			/*
 488			 * Newline or semicolon here is optional (but note
 489			 * that the original Bourne shell only allowed NL).
 490			 */
 491			if (lasttoken != TNL && lasttoken != TSEMI)
 492				tokpushback++;
 493		}
 494		checkkwd = CHKNL | CHKKWD | CHKALIAS;
 495		if ((t = readtoken()) == TDO)
 496			t = TDONE;
 497		else if (t == TBEGIN)
 498			t = TEND;
 499		else
 500			synexpect(-1);
 501		n1->nfor.body = list(0, 0);
 502		if (readtoken() != t)
 503			synexpect(t);
 504		checkkwd = CHKKWD | CHKALIAS;
 505		break;
 506	case TCASE:
 507		n1 = (union node *)stalloc(sizeof (struct ncase));
 508		n1->type = NCASE;
 509		if (readtoken() != TWORD)
 510			synexpect(TWORD);
 511		n1->ncase.expr = n2 = (union node *)stalloc(sizeof (struct narg));
 512		n2->type = NARG;
 513		n2->narg.text = wordtext;
 514		n2->narg.backquote = backquotelist;
 515		n2->narg.next = NULL;
 516		while (readtoken() == TNL);
 517		if (lasttoken != TWORD || ! equal(wordtext, "in"))
 518			synerror("expecting \"in\"");
 519		cpp = &n1->ncase.cases;
 520		checkkwd = CHKNL | CHKKWD, readtoken();
 521		while (lasttoken != TESAC) {
 522			*cpp = cp = (union node *)stalloc(sizeof (struct nclist));
 523			cp->type = NCLIST;
 524			app = &cp->nclist.pattern;
 525			if (lasttoken == TLP)
 526				readtoken();
 527			for (;;) {
 528				*app = ap = (union node *)stalloc(sizeof (struct narg));
 529				ap->type = NARG;
 530				ap->narg.text = wordtext;
 531				ap->narg.backquote = backquotelist;
 532				checkkwd = CHKNL | CHKKWD;
 533				if (readtoken() != TPIPE)
 534					break;
 535				app = &ap->narg.next;
 536				readtoken();
 537			}
 538			ap->narg.next = NULL;
 539			if (lasttoken != TRP)
 540				synexpect(TRP);
 541			cp->nclist.body = list(0, 0);
 542
 543			checkkwd = CHKNL | CHKKWD | CHKALIAS;
 544			if ((t = readtoken()) != TESAC) {
 545				if (t == TENDCASE)
 546					;
 547				else if (t == TFALLTHRU)
 548					cp->type = NCLISTFALLTHRU;
 549				else
 550					synexpect(TENDCASE);
 551				checkkwd = CHKNL | CHKKWD, readtoken();
 552			}
 553			cpp = &cp->nclist.next;
 554		}
 555		*cpp = NULL;
 556		checkkwd = CHKKWD | CHKALIAS;
 557		break;
 558	case TLP:
 559		n1 = (union node *)stalloc(sizeof (struct nredir));
 560		n1->type = NSUBSHELL;
 561		n1->nredir.n = list(0, 0);
 562		n1->nredir.redirect = NULL;
 563		if (readtoken() != TRP)
 564			synexpect(TRP);
 565		checkkwd = CHKKWD | CHKALIAS;
 566		is_subshell = 1;
 567		break;
 568	case TBEGIN:
 569		n1 = list(0, 0);
 570		if (readtoken() != TEND)
 571			synexpect(TEND);
 572		checkkwd = CHKKWD | CHKALIAS;
 573		break;
 574	/* Handle an empty command like other simple commands.  */
 575	case TBACKGND:
 576	case TSEMI:
 577	case TAND:
 578	case TOR:
 579		/*
 580		 * An empty command before a ; doesn't make much sense, and
 581		 * should certainly be disallowed in the case of `if ;'.
 582		 */
 583		if (!redir)
 584			synexpect(-1);
 585	case TNL:
 586	case TEOF:
 587	case TWORD:
 588	case TRP:
 589		tokpushback++;
 590		n1 = simplecmd(rpp, redir);
 591		return n1;
 592	default:
 593		synexpect(-1);
 594	}
 595
 596	/* Now check for redirection which may follow command */
 597	while (readtoken() == TREDIR) {
 598		*rpp = n2 = redirnode;
 599		rpp = &n2->nfile.next;
 600		parsefname();
 601	}
 602	tokpushback++;
 603	*rpp = NULL;
 604	if (redir) {
 605		if (!is_subshell) {
 606			n2 = (union node *)stalloc(sizeof (struct nredir));
 607			n2->type = NREDIR;
 608			n2->nredir.n = n1;
 609			n1 = n2;
 610		}
 611		n1->nredir.redirect = redir;
 612	}
 613
 614	return n1;
 615}
 616
 617
 618static union node *
 619simplecmd(union node **rpp, union node *redir)
 620{
 621	union node *args, **app;
 622	union node **orig_rpp = rpp;
 623	union node *n = NULL;
 624	int special;
 625	int savecheckkwd;
 626
 627	/* If we don't have any redirections already, then we must reset */
 628	/* rpp to be the address of the local redir variable.  */
 629	if (redir == 0)
 630		rpp = &redir;
 631
 632	args = NULL;
 633	app = &args;
 634	/*
 635	 * We save the incoming value, because we need this for shell
 636	 * functions.  There can not be a redirect or an argument between
 637	 * the function name and the open parenthesis.
 638	 */
 639	orig_rpp = rpp;
 640
 641	savecheckkwd = CHKALIAS;
 642
 643	for (;;) {
 644		checkkwd = savecheckkwd;
 645		if (readtoken() == TWORD) {
 646			n = (union node *)stalloc(sizeof (struct narg));
 647			n->type = NARG;
 648			n->narg.text = wordtext;
 649			n->narg.backquote = backquotelist;
 650			*app = n;
 651			app = &n->narg.next;
 652			if (savecheckkwd != 0 && !isassignment(wordtext))
 653				savecheckkwd = 0;
 654		} else if (lasttoken == TREDIR) {
 655			*rpp = n = redirnode;
 656			rpp = &n->nfile.next;
 657			parsefname();	/* read name of redirection file */
 658		} else if (lasttoken == TLP && app == &args->narg.next
 659					    && rpp == orig_rpp) {
 660			/* We have a function */
 661			if (readtoken() != TRP)
 662				synexpect(TRP);
 663			funclinno = plinno;
 664			/*
 665			 * - Require plain text.
 666			 * - Functions with '/' cannot be called.
 667			 * - Reject name=().
 668			 * - Reject ksh extended glob patterns.
 669			 */
 670			if (!noexpand(n->narg.text) || quoteflag ||
 671			    strchr(n->narg.text, '/') ||
 672			    strchr("!%*+-=?@}~",
 673				n->narg.text[strlen(n->narg.text) - 1]))
 674				synerror("Bad function name");
 675			rmescapes(n->narg.text);
 676			if (find_builtin(n->narg.text, &special) >= 0 &&
 677			    special)
 678				synerror("Cannot override a special builtin with a function");
 679			n->type = NDEFUN;
 680			n->narg.next = command();
 681			funclinno = 0;
 682			return n;
 683		} else {
 684			tokpushback++;
 685			break;
 686		}
 687	}
 688	*app = NULL;
 689	*rpp = NULL;
 690	n = (union node *)stalloc(sizeof (struct ncmd));
 691	n->type = NCMD;
 692	n->ncmd.args = args;
 693	n->ncmd.redirect = redir;
 694	return n;
 695}
 696
 697static union node *
 698makename(void)
 699{
 700	union node *n;
 701
 702	n = (union node *)stalloc(sizeof (struct narg));
 703	n->type = NARG;
 704	n->narg.next = NULL;
 705	n->narg.text = wordtext;
 706	n->narg.backquote = backquotelist;
 707	return n;
 708}
 709
 710void
 711fixredir(union node *n, const char *text, int err)
 712{
 713	TRACE(("Fix redir %s %d\n", text, err));
 714	if (!err)
 715		n->ndup.vname = NULL;
 716
 717	if (is_digit(text[0]) && text[1] == '\0')
 718		n->ndup.dupfd = digit_val(text[0]);
 719	else if (text[0] == '-' && text[1] == '\0')
 720		n->ndup.dupfd = -1;
 721	else {
 722
 723		if (err)
 724			synerror("Bad fd number");
 725		else
 726			n->ndup.vname = makename();
 727	}
 728}
 729
 730
 731static void
 732parsefname(void)
 733{
 734	union node *n = redirnode;
 735
 736	if (readtoken() != TWORD)
 737		synexpect(-1);
 738	if (n->type == NHERE) {
 739		struct heredoc *here = heredoc;
 740		struct heredoc *p;
 741		int i;
 742
 743		if (quoteflag == 0)
 744			n->type = NXHERE;
 745		TRACE(("Here document %d\n", n->type));
 746		if (here->striptabs) {
 747			while (*wordtext == '\t')
 748				wordtext++;
 749		}
 750		if (! noexpand(wordtext) || (i = strlen(wordtext)) == 0 || i > EOFMARKLEN)
 751			synerror("Illegal eof marker for << redirection");
 752		rmescapes(wordtext);
 753		here->eofmark = wordtext;
 754		here->next = NULL;
 755		if (heredoclist == NULL)
 756			heredoclist = here;
 757		else {
 758			for (p = heredoclist ; p->next ; p = p->next);
 759			p->next = here;
 760		}
 761	} else if (n->type == NTOFD || n->type == NFROMFD) {
 762		fixredir(n, wordtext, 0);
 763	} else {
 764		n->nfile.fname = makename();
 765	}
 766}
 767
 768
 769/*
 770 * Input any here documents.
 771 */
 772
 773static void
 774parseheredoc(void)
 775{
 776	struct heredoc *here;
 777	union node *n;
 778
 779	while (heredoclist) {
 780		here = heredoclist;
 781		heredoclist = here->next;
 782		if (needprompt) {
 783			setprompt(2);
 784			needprompt = 0;
 785		}
 786		readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
 787				here->eofmark, here->striptabs);
 788		n = (union node *)stalloc(sizeof (struct narg));
 789		n->narg.type = NARG;
 790		n->narg.next = NULL;
 791		n->narg.text = wordtext;
 792		n->narg.backquote = backquotelist;
 793		here->here->nhere.doc = n;
 794	}
 795}
 796
 797static int
 798peektoken(void)
 799{
 800	int t;
 801
 802	t = readtoken();
 803	tokpushback++;
 804	return (t);
 805}
 806
 807static int
 808readtoken(void)
 809{
 810	int t;
 811	struct alias *ap;
 812#ifdef DEBUG
 813	int alreadyseen = tokpushback;
 814#endif
 815
 816	top:
 817	t = xxreadtoken();
 818
 819	/*
 820	 * eat newlines
 821	 */
 822	if (checkkwd & CHKNL) {
 823		while (t == TNL) {
 824			parseheredoc();
 825			t = xxreadtoken();
 826		}
 827	}
 828
 829	/*
 830	 * check for keywords and aliases
 831	 */
 832	if (t == TWORD && !quoteflag)
 833	{
 834		const char * const *pp;
 835
 836		if (checkkwd & CHKKWD)
 837			for (pp = parsekwd; *pp; pp++) {
 838				if (**pp == *wordtext && equal(*pp, wordtext))
 839				{
 840					lasttoken = t = pp - parsekwd + KWDOFFSET;
 841					TRACE(("keyword %s recognized\n", tokname[t]));
 842					goto out;
 843				}
 844			}
 845		if (checkkwd & CHKALIAS &&
 846		    (ap = lookupalias(wordtext, 1)) != NULL) {
 847			pushstring(ap->val, strlen(ap->val), ap);
 848			goto top;
 849		}
 850	}
 851out:
 852	if (t != TNOT)
 853		checkkwd = 0;
 854
 855#ifdef DEBUG
 856	if (!alreadyseen)
 857	    TRACE(("token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 858	else
 859	    TRACE(("reread token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
 860#endif
 861	return (t);
 862}
 863
 864
 865/*
 866 * Read the next input token.
 867 * If the token is a word, we set backquotelist to the list of cmds in
 868 *	backquotes.  We set quoteflag to true if any part of the word was
 869 *	quoted.
 870 * If the token is TREDIR, then we set redirnode to a structure containing
 871 *	the redirection.
 872 * In all cases, the variable startlinno is set to the number of the line
 873 *	on which the token starts.
 874 *
 875 * [Change comment:  here documents and internal procedures]
 876 * [Readtoken shouldn't have any arguments.  Perhaps we should make the
 877 *  word parsing code into a separate routine.  In this case, readtoken
 878 *  doesn't need to have any internal procedures, but parseword does.
 879 *  We could also make parseoperator in essence the main routine, and
 880 *  have parseword (readtoken1?) handle both words and redirection.]
 881 */
 882
 883#define RETURN(token)	return lasttoken = token
 884
 885static int
 886xxreadtoken(void)
 887{
 888	int c;
 889
 890	if (tokpushback) {
 891		tokpushback = 0;
 892		return lasttoken;
 893	}
 894	if (needprompt) {
 895		setprompt(2);
 896		needprompt = 0;
 897	}
 898	startlinno = plinno;
 899	for (;;) {	/* until token or start of word found */
 900		c = pgetc_macro();
 901		switch (c) {
 902		case ' ': case '\t':
 903			continue;
 904		case '#':
 905			while ((c = pgetc()) != '\n' && c != PEOF);
 906			pungetc();
 907			continue;
 908		case '\\':
 909			if (pgetc() == '\n') {
 910				startlinno = ++plinno;
 911				if (doprompt)
 912					setprompt(2);
 913				else
 914					setprompt(0);
 915				continue;
 916			}
 917			pungetc();
 918			goto breakloop;
 919		case '\n':
 920			plinno++;
 921			needprompt = doprompt;
 922			RETURN(TNL);
 923		case PEOF:
 924			RETURN(TEOF);
 925		case '&':
 926			if (pgetc() == '&')
 927				RETURN(TAND);
 928			pungetc();
 929			RETURN(TBACKGND);
 930		case '|':
 931			if (pgetc() == '|')
 932				RETURN(TOR);
 933			pungetc();
 934			RETURN(TPIPE);
 935		case ';':
 936			c = pgetc();
 937			if (c == ';')
 938				RETURN(TENDCASE);
 939			else if (c == '&')
 940				RETURN(TFALLTHRU);
 941			pungetc();
 942			RETURN(TSEMI);
 943		case '(':
 944			RETURN(TLP);
 945		case ')':
 946			RETURN(TRP);
 947		default:
 948			goto breakloop;
 949		}
 950	}
 951breakloop:
 952	return readtoken1(c, BASESYNTAX, (char *)NULL, 0);
 953#undef RETURN
 954}
 955
 956
 957#define MAXNEST_static 8
 958struct tokenstate
 959{
 960	const char *syntax; /* *SYNTAX */
 961	int parenlevel; /* levels of parentheses in arithmetic */
 962	enum tokenstate_category
 963	{
 964		TSTATE_TOP,
 965		TSTATE_VAR_OLD, /* ${var+-=?}, inherits dquotes */
 966		TSTATE_VAR_NEW, /* other ${var...}, own dquote state */
 967		TSTATE_ARITH
 968	} category;
 969};
 970
 971
 972/*
 973 * Called to parse command substitutions.
 974 */
 975
 976static char *
 977parsebackq(char *out, struct nodelist **pbqlist,
 978		int oldstyle, int dblquote, int quoted)
 979{
 980	struct nodelist **nlpp;
 981	union node *n;
 982	char *volatile str;
 983	struct jmploc jmploc;
 984	struct jmploc *const savehandler = handler;
 985	int savelen;
 986	int saveprompt;
 987	const int bq_startlinno = plinno;
 988	char *volatile ostr = NULL;
 989	struct parsefile *const savetopfile = getcurrentfile();
 990	struct heredoc *const saveheredoclist = heredoclist;
 991	struct heredoc *here;
 992
 993	str = NULL;
 994	if (setjmp(jmploc.loc)) {
 995		popfilesupto(savetopfile);
 996		if (str)
 997			ckfree(str);
 998		if (ostr)
 999			ckfree(ostr);
1000		heredoclist = saveheredoclist;
1001		handler = savehandler;
1002		if (exception == EXERROR) {
1003			startlinno = bq_startlinno;
1004			synerror("Error in command substitution");
1005		}
1006		longjmp(handler->loc, 1);
1007	}
1008	INTOFF;
1009	savelen = out - stackblock();
1010	if (savelen > 0) {
1011		str = ckmalloc(savelen);
1012		memcpy(str, stackblock(), savelen);
1013	}
1014	handler = &jmploc;
1015	heredoclist = NULL;
1016	INTON;
1017        if (oldstyle) {
1018                /* We must read until the closing backquote, giving special
1019                   treatment to some slashes, and then push the string and
1020                   reread it as input, interpreting it normally.  */
1021                char *oout;
1022                int c;
1023                int olen;
1024
1025
1026                STARTSTACKSTR(oout);
1027		for (;;) {
1028			if (needprompt) {
1029				setprompt(2);
1030				needprompt = 0;
1031			}
1032			CHECKSTRSPACE(2, oout);
1033			switch (c = pgetc()) {
1034			case '`':
1035				goto done;
1036
1037			case '\\':
1038                                if ((c = pgetc()) == '\n') {
1039					plinno++;
1040					if (doprompt)
1041						setprompt(2);
1042					else
1043						setprompt(0);
1044					/*
1045					 * If eating a newline, avoid putting
1046					 * the newline into the new character
1047					 * stream (via the USTPUTC after the
1048					 * switch).
1049					 */
1050					continue;
1051				}
1052                                if (c != '\\' && c != '`' && c != '$'
1053                                    && (!dblquote || c != '"'))
1054                                        USTPUTC('\\', oout);
1055				break;
1056
1057			case '\n':
1058				plinno++;
1059				needprompt = doprompt;
1060				break;
1061
1062			case PEOF:
1063			        startlinno = plinno;
1064				synerror("EOF in backquote substitution");
1065 				break;
1066
1067			default:
1068				break;
1069			}
1070			USTPUTC(c, oout);
1071                }
1072done:
1073                USTPUTC('\0', oout);
1074                olen = oout - stackblock();
1075		INTOFF;
1076		ostr = ckmalloc(olen);
1077		memcpy(ostr, stackblock(), olen);
1078		setinputstring(ostr, 1);
1079		INTON;
1080        }
1081	nlpp = pbqlist;
1082	while (*nlpp)
1083		nlpp = &(*nlpp)->next;
1084	*nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
1085	(*nlpp)->next = NULL;
1086
1087	if (oldstyle) {
1088		saveprompt = doprompt;
1089		doprompt = 0;
1090	}
1091
1092	n = list(0, oldstyle);
1093
1094	if (oldstyle)
1095		doprompt = saveprompt;
1096	else {
1097		if (readtoken() != TRP)
1098			synexpect(TRP);
1099	}
1100
1101	(*nlpp)->n = n;
1102        if (oldstyle) {
1103		/*
1104		 * Start reading from old file again, ignoring any pushed back
1105		 * tokens left from the backquote parsing
1106		 */
1107                popfile();
1108		tokpushback = 0;
1109	}
1110	STARTSTACKSTR(out);
1111	CHECKSTRSPACE(savelen + 1, out);
1112	INTOFF;
1113	if (str) {
1114		memcpy(out, str, savelen);
1115		STADJUST(savelen, out);
1116		ckfree(str);
1117		str = NULL;
1118	}
1119	if (ostr) {
1120		ckfree(ostr);
1121		ostr = NULL;
1122	}
1123	here = saveheredoclist;
1124	if (here != NULL) {
1125		while (here->next != NULL)
1126			here = here->next;
1127		here->next = heredoclist;
1128		heredoclist = saveheredoclist;
1129	}
1130	handler = savehandler;
1131	INTON;
1132	if (quoted)
1133		USTPUTC(CTLBACKQ | CTLQUOTE, out);
1134	else
1135		USTPUTC(CTLBACKQ, out);
1136	return out;
1137}
1138
1139
1140/*
1141 * Called to parse a backslash escape sequence inside $'...'.
1142 * The backslash has already been read.
1143 */
1144static char *
1145readcstyleesc(char *out)
1146{
1147	int c, v, i, n;
1148
1149	c = pgetc();
1150	switch (c) {
1151	case '\0':
1152		synerror("Unterminated quoted string");
1153	case '\n':
1154		plinno++;
1155		if (doprompt)
1156			setprompt(2);
1157		else
1158			setprompt(0);
1159		return out;
1160	case '\\':
1161	case '\'':
1162	case '"':
1163		v = c;
1164		break;
1165	case 'a': v = '\a'; break;
1166	case 'b': v = '\b'; break;
1167	case 'e': v = '\033'; break;
1168	case 'f': v = '\f'; break;
1169	case 'n': v = '\n'; break;
1170	case 'r': v = '\r'; break;
1171	case 't': v = '\t'; break;
1172	case 'v': v = '\v'; break;
1173	case 'x':
1174		  v = 0;
1175		  for (;;) {
1176			  c = pgetc();
1177			  if (c >= '0' && c <= '9')
1178				  v = (v << 4) + c - '0';
1179			  else if (c >= 'A' && c <= 'F')
1180				  v = (v << 4) + c - 'A' + 10;
1181			  else if (c >= 'a' && c <= 'f')
1182				  v = (v << 4) + c - 'a' + 10;
1183			  else
1184				  break;
1185		  }
1186		  pungetc();
1187		  break;
1188	case '0': case '1': case '2': case '3':
1189	case '4': case '5': case '6': case '7':
1190		  v = c - '0';
1191		  c = pgetc();
1192		  if (c >= '0' && c <= '7') {
1193			  v <<= 3;
1194			  v += c - '0';
1195			  c = pgetc();
1196			  if (c >= '0' && c <= '7') {
1197				  v <<= 3;
1198				  v += c - '0';
1199			  } else
1200				  pungetc();
1201		  } else
1202			  pungetc();
1203		  break;
1204	case 'c':
1205		  c = pgetc();
1206		  if (c < 0x3f || c > 0x7a || c == 0x60)
1207			  synerror("Bad escape sequence");
1208		  if (c == '\\' && pgetc() != '\\')
1209			  synerror("Bad escape sequence");
1210		  if (c == '?')
1211			  v = 127;
1212		  else
1213			  v = c & 0x1f;
1214		  break;
1215	case 'u':
1216	case 'U':
1217		  n = c == 'U' ? 8 : 4;
1218		  v = 0;
1219		  for (i = 0; i < n; i++) {
1220			  c = pgetc();
1221			  if (c >= '0' && c <= '9')
1222				  v = (v << 4) + c - '0';
1223			  else if (c >= 'A' && c <= 'F')
1224				  v = (v << 4) + c - 'A' + 10;
1225			  else if (c >= 'a' && c <= 'f')
1226				  v = (v << 4) + c - 'a' + 10;
1227			  else
1228				  synerror("Bad escape sequence");
1229		  }
1230		  if (v == 0 || (v >= 0xd800 && v <= 0xdfff))
1231			  synerror("Bad escape sequence");
1232		  /* We really need iconv here. */
1233		  if (initial_localeisutf8 && v > 127) {
1234			  CHECKSTRSPACE(4, out);
1235			  /*
1236			   * We cannot use wctomb() as the locale may have
1237			   * changed.
1238			   */
1239			  if (v <= 0x7ff) {
1240				  USTPUTC(0xc0 | v >> 6, out);
1241				  USTPUTC(0x80 | (v & 0x3f), out);
1242				  return out;
1243			  } else if (v <= 0xffff) {
1244				  USTPUTC(0xe0 | v >> 12, out);
1245				  USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
1246				  USTPUTC(0x80 | (v & 0x3f), out);
1247				  return out;
1248			  } else if (v <= 0x10ffff) {
1249				  USTPUTC(0xf0 | v >> 18, out);
1250				  USTPUTC(0x80 | ((v >> 12) & 0x3f), out);
1251				  USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
1252				  USTPUTC(0x80 | (v & 0x3f), out);
1253				  return out;
1254			  }
1255		  }
1256		  if (v > 127)
1257			  v = '?';
1258		  break;
1259	default:
1260		  synerror("Bad escape sequence");
1261	}
1262	v = (char)v;
1263	/*
1264	 * We can't handle NUL bytes.
1265	 * POSIX says we should skip till the closing quote.
1266	 */
1267	if (v == '\0') {
1268		while ((c = pgetc()) != '\'') {
1269			if (c == '\\')
1270				c = pgetc();
1271			if (c == PEOF)
1272				synerror("Unterminated quoted string");
1273		}
1274		pungetc();
1275		return out;
1276	}
1277	if (SQSYNTAX[v] == CCTL)
1278		USTPUTC(CTLESC, out);
1279	USTPUTC(v, out);
1280	return out;
1281}
1282
1283
1284/*
1285 * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
1286 * is not NULL, read a here document.  In the latter case, eofmark is the
1287 * word which marks the end of the document and striptabs is true if
1288 * leading tabs should be stripped from the document.  The argument firstc
1289 * is the first character of the input token or document.
1290 *
1291 * Because C does not have internal subroutines, I have simulated them
1292 * using goto's to implement the subroutine linkage.  The following macros
1293 * will run code that appears at the end of readtoken1.
1294 */
1295
1296#define CHECKEND()	{goto checkend; checkend_return:;}
1297#define PARSEREDIR()	{goto parseredir; parseredir_return:;}
1298#define PARSESUB()	{goto parsesub; parsesub_return:;}
1299#define	PARSEARITH()	{goto parsearith; parsearith_return:;}
1300
1301static int
1302readtoken1(int firstc, char const *initialsyntax, char *eofmark, int striptabs)
1303{
1304	int c = firstc;
1305	char *out;
1306	int len;
1307	char line[EOFMARKLEN + 1];
1308	struct nodelist *bqlist;
1309	int quotef;
1310	int newvarnest;
1311	int level;
1312	int synentry;
1313	struct tokenstate state_static[MAXNEST_static];
1314	int maxnest = MAXNEST_static;
1315	struct tokenstate *state = state_static;
1316	int sqiscstyle = 0;
1317
1318	startlinno = plinno;
1319	quotef = 0;
1320	bqlist = NULL;
1321	newvarnest = 0;
1322	level = 0;
1323	state[level].syntax = initialsyntax;
1324	state[level].parenlevel = 0;
1325	state[level].category = TSTATE_TOP;
1326
1327	STARTSTACKSTR(out);
1328	loop: {	/* for each line, until end of word */
1329		CHECKEND();	/* set c to PEOF if at end of here document */
1330		for (;;) {	/* until end of line or end of word */
1331			CHECKSTRSPACE(4, out);	/* permit 4 calls to USTPUTC */
1332
1333			synentry = state[level].syntax[c];
1334
1335			switch(synentry) {
1336			case CNL:	/* '\n' */
1337				if (state[level].syntax == BASESYNTAX)
1338					goto endword;	/* exit outer loop */
1339				USTPUTC(c, out);
1340				plinno++;
1341				if (doprompt)
1342					setprompt(2);
1343				else
1344					setprompt(0);
1345				c = pgetc();
1346				goto loop;		/* continue outer loop */
1347			case CSBACK:
1348				if (sqiscstyle) {
1349					out = readcstyleesc(out);
1350					break;
1351				}
1352				/* FALLTHROUGH */
1353			case CWORD:
1354				USTPUTC(c, out);
1355				break;
1356			case CCTL:
1357				if (eofmark == NULL || initialsyntax != SQSYNTAX)
1358					USTPUTC(CTLESC, out);
1359				USTPUTC(c, out);
1360				break;
1361			case CBACK:	/* backslash */
1362				c = pgetc();
1363				if (c == PEOF) {
1364					USTPUTC('\\', out);
1365					pungetc();
1366				} else if (c == '\n') {
1367					plinno++;
1368					if (doprompt)
1369						setprompt(2);
1370					else
1371						setprompt(0);
1372				} else {
1373					if (state[level].syntax == DQSYNTAX &&
1374					    c != '\\' && c != '`' && c != '$' &&
1375					    (c != '"' || (eofmark != NULL &&
1376						newvarnest == 0)) &&
1377					    (c != '}' || state[level].category != TSTATE_VAR_OLD))
1378						USTPUTC('\\', out);
1379					if ((eofmark == NULL ||
1380					    newvarnest > 0) &&
1381					    state[level].syntax == BASESYNTAX)
1382						USTPUTC(CTLQUOTEMARK, out);
1383					if (SQSYNTAX[c] == CCTL)
1384						USTPUTC(CTLESC, out);
1385					USTPUTC(c, out);
1386					if ((eofmark == NULL ||
1387					    newvarnest > 0) &&
1388					    state[level].syntax == BASESYNTAX &&
1389					    state[level].category == TSTATE_VAR_OLD)
1390						USTPUTC(CTLQUOTEEND, out);
1391					quotef++;
1392				}
1393				break;
1394			case CSQUOTE:
1395				USTPUTC(CTLQUOTEMARK, out);
1396				state[level].syntax = SQSYNTAX;
1397				sqiscstyle = 0;
1398				break;
1399			case CDQUOTE:
1400				USTPUTC(CTLQUOTEMARK, out);
1401				state[level].syntax = DQSYNTAX;
1402				break;
1403			case CENDQUOTE:
1404				if (eofmark != NULL && newvarnest == 0)
1405					USTPUTC(c, out);
1406				else {
1407					if (state[level].category == TSTATE_VAR_OLD)
1408						USTPUTC(CTLQUOTEEND, out);
1409					state[level].syntax = BASESYNTAX;
1410					quotef++;
1411				}
1412				break;
1413			case CVAR:	/* '$' */
1414				PARSESUB();		/* parse substitution */
1415				break;
1416			case CENDVAR:	/* '}' */
1417				if (level > 0 &&
1418				    ((state[level].category == TSTATE_VAR_OLD &&
1419				      state[level].syntax ==
1420				      state[level - 1].syntax) ||
1421				    (state[level].category == TSTATE_VAR_NEW &&
1422				     state[level].syntax == BASESYNTAX))) {
1423					if (state[level].category == TSTATE_VAR_NEW)
1424						newvarnest--;
1425					level--;
1426					USTPUTC(CTLENDVAR, out);
1427				} else {
1428					USTPUTC(c, out);
1429				}
1430				break;
1431			case CLP:	/* '(' in arithmetic */
1432				state[level].parenlevel++;
1433				USTPUTC(c, out);
1434				break;
1435			case CRP:	/* ')' in arithmetic */
1436				if (state[level].parenlevel > 0) {
1437					USTPUTC(c, out);
1438					--state[level].parenlevel;
1439				} else {
1440					if (pgetc() == ')') {
1441						if (level > 0 &&
1442						    state[level].category == TSTATE_ARITH) {
1443							level--;
1444							USTPUTC(CTLENDARI, out);
1445						} else
1446							USTPUTC(')', out);
1447					} else {
1448						/*
1449						 * unbalanced parens
1450						 *  (don't 2nd guess - no error)
1451						 */
1452						pungetc();
1453						USTPUTC(')', out);
1454					}
1455				}
1456				break;
1457			case CBQUOTE:	/* '`' */
1458				out = parsebackq(out, &bqlist, 1,
1459				    state[level].syntax == DQSYNTAX &&
1460				    (eofmark == NULL || newvarnest > 0),
1461				    state[level].syntax == DQSYNTAX || state[level].syntax == ARISYNTAX);
1462				break;
1463			case CEOF:
1464				goto endword;		/* exit outer loop */
1465			case CIGN:
1466				break;
1467			default:
1468				if (level == 0)
1469					goto endword;	/* exit outer loop */
1470				USTPUTC(c, out);
1471			}
1472			c = pgetc_macro();
1473		}
1474	}
1475endword:
1476	if (state[level].syntax == ARISYNTAX)
1477		synerror("Missing '))'");
1478	if (state[level].syntax != BASESYNTAX && eofmark == NULL)
1479		synerror("Unterminated quoted string");
1480	if (state[level].category == TSTATE_VAR_OLD ||
1481	    state[level].category == TSTATE_VAR_NEW) {
1482		startlinno = plinno;
1483		synerror("Missing '}'");
1484	}
1485	if (state != state_static)
1486		parser_temp_free_upto(state);
1487	USTPUTC('\0', out);
1488	len = out - stackblock();
1489	out = stackblock();
1490	if (eofmark == NULL) {
1491		if ((c == '>' || c == '<')
1492		 && quotef == 0
1493		 && len <= 2
1494		 && (*out == '\0' || is_digit(*out))) {
1495			PARSEREDIR();
1496			return lasttoken = TREDIR;
1497		} else {
1498			pungetc();
1499		}
1500	}
1501	quoteflag = quotef;
1502	backquotelist = bqlist;
1503	grabstackblock(len);
1504	wordtext = out;
1505	return lasttoken = TWORD;
1506/* end of readtoken routine */
1507
1508
1509/*
1510 * Check to see whether we are at the end of the here document.  When this
1511 * is called, c is set to the first character of the next input line.  If
1512 * we are at the end of the here document, this routine sets the c to PEOF.
1513 */
1514
1515checkend: {
1516	if (eofmark) {
1517		if (striptabs) {
1518			while (c == '\t')
1519				c = pgetc();
1520		}
1521		if (c == *eofmark) {
1522			if (pfgets(line, sizeof line) != NULL) {
1523				char *p, *q;
1524
1525				p = line;
1526				for (q = eofmark + 1 ; *q && *p == *q ; p++, q++);
1527				if ((*p == '\0' || *p == '\n') && *q == '\0') {
1528					c = PEOF;
1529					if (*p == '\n') {
1530						plinno++;
1531						needprompt = doprompt;
1532					}
1533				} else {
1534					pushstring(line, strlen(line), NULL);
1535				}
1536			}
1537		}
1538	}
1539	goto checkend_return;
1540}
1541
1542
1543/*
1544 * Parse a redirection operator.  The variable "out" points to a string
1545 * specifying the fd to be redirected.  The variable "c" contains the
1546 * first character of the redirection operator.
1547 */
1548
1549parseredir: {
1550	char fd = *out;
1551	union node *np;
1552
1553	np = (union node *)stalloc(sizeof (struct nfile));
1554	if (c == '>') {
1555		np->nfile.fd = 1;
1556		c = pgetc();
1557		if (c == '>')
1558			np->type = NAPPEND;
1559		else if (c == '&')
1560			np->type = NTOFD;
1561		else if (c == '|')
1562			np->type = NCLOBBER;
1563		else {
1564			np->type = NTO;
1565			pungetc();
1566		}
1567	} else {	/* c == '<' */
1568		np->nfile.fd = 0;
1569		c = pgetc();
1570		if (c == '<') {
1571			if (sizeof (struct nfile) != sizeof (struct nhere)) {
1572				np = (union node *)stalloc(sizeof (struct nhere));
1573				np->nfile.fd = 0;
1574			}
1575			np->type = NHERE;
1576			heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
1577			heredoc->here = np;
1578			if ((c = pgetc()) == '-') {
1579				heredoc->striptabs = 1;
1580			} else {
1581				heredoc->striptabs = 0;
1582				pungetc();
1583			}
1584		} else if (c == '&')
1585			np->type = NFROMFD;
1586		else if (c == '>')
1587			np->type = NFROMTO;
1588		else {
1589			np->type = NFROM;
1590			pungetc();
1591		}
1592	}
1593	if (fd != '\0')
1594		np->nfile.fd = digit_val(fd);
1595	redirnode = np;
1596	goto parseredir_return;
1597}
1598
1599
1600/*
1601 * Parse a substitution.  At this point, we have read the dollar sign
1602 * and nothing else.
1603 */
1604
1605parsesub: {
1606	char buf[10];
1607	int subtype;
1608	int typeloc;
1609	int flags;
1610	char *p;
1611	static const char types[] = "}-+?=";
1612	int bracketed_name = 0; /* used to handle ${[0-9]*} variables */
1613	int linno;
1614	int length;
1615	int c1;
1616
1617	c = pgetc();
1618	if (c == '(') {	/* $(command) or $((arith)) */
1619		if (pgetc() == '(') {
1620			PARSEARITH();
1621		} else {
1622			pungetc();
1623			out = parsebackq(out, &bqlist, 0,
1624			    state[level].syntax == DQSYNTAX &&
1625			    (eofmark == NULL || newvarnest > 0),
1626			    state[level].syntax == DQSYNTAX ||
1627			    state[level].syntax == ARISYNTAX);
1628		}
1629	} else if (c == '{' || is_name(c) || is_special(c)) {
1630		USTPUTC(CTLVAR, out);
1631		typeloc = out - stackblock();
1632		USTPUTC(VSNORMAL, out);
1633		subtype = VSNORMAL;
1634		flags = 0;
1635		if (c == '{') {
1636			bracketed_name = 1;
1637			c = pgetc();
1638			subtype = 0;
1639		}
1640varname:
1641		if (!is_eof(c) && is_name(c)) {
1642			length = 0;
1643			do {
1644				STPUTC(c, out);
1645				c = pgetc();
1646				length++;
1647			} while (!is_eof(c) && is_in_name(c));
1648			if (length == 6 &&
1649			    strncmp(out - length, "LINENO", length) == 0) {
1650				/* Replace the variable name with the
1651				 * current line number. */
1652				linno = plinno;
1653				if (funclinno != 0)
1654					linno -= funclinno - 1;
1655				snprintf(buf, sizeof(buf), "%d", linno);
1656				STADJUST(-6, out);
1657				STPUTS(buf, out);
1658				flags |= VSLINENO;
1659			}
1660		} else if (is_digit(c)) {
1661			if (bracketed_name) {
1662				do {
1663					STPUTC(c, out);
1664					c = pgetc();
1665				} while (is_digit(c));
1666			} else {
1667				STPUTC(c, out);
1668				c = pgetc();
1669			}
1670		} else if (is_special(c)) {
1671			c1 = c;
1672			c = pgetc();
1673			if (subtype == 0 && c1 == '#') {
1674				subtype = VSLENGTH;
1675				if (strchr(types, c) == NULL && c != ':' &&
1676				    c != '#' && c != '%')
1677					goto varname;
1678				c1 = c;
1679				c = pgetc();
1680				if (c1 != '}' && c == '}') {
1681					pungetc();
1682					c = c1;
1683					goto varname;
1684				}
1685				pungetc();
1686				c = c1;
1687				c1 = '#';
1688				subtype = 0;
1689			}
1690			USTPUTC(c1, out);
1691		} else {
1692			subtype = VSERROR;
1693			if (c == '}')
1694				pungetc();
1695			else if (c == '\n' || c == PEOF)
1696				synerror("Unexpected end of line in substitution");
1697			else
1698				USTPUTC(c, out);
1699		}
1700		if (subtype == 0) {
1701			switch (c) {
1702			case ':':
1703				flags |= VSNUL;
1704				c = pgetc();
1705				/*FALLTHROUGH*/
1706			default:
1707				p = strchr(types, c);
1708				if (p == NULL) {
1709					if (c == '\n' || c == PEOF)
1710						synerror("Unexpected end of line in substitution");
1711					if (flags == VSNUL)
1712						STPUTC(':', out);
1713					STPUTC(c, out);
1714					subtype = VSERROR;
1715				} else
1716					subtype = p - types + VSNORMAL;
1717				break;
1718			case '%':
1719			case '#':
1720				{
1721					int cc = c;
1722					subtype = c == '#' ? VSTRIMLEFT :
1723							     VSTRIMRIGHT;
1724					c = pgetc();
1725					if (c == cc)
1726						subtype++;
1727					else
1728						pungetc();
1729					break;
1730				}
1731			}
1732		} else if (subtype != VSERROR) {
1733			if (subtype == VSLENGTH && c != '}')
1734				subtype = VSERROR;
1735			pungetc();
1736		}
1737		STPUTC('=', out);
1738		if (state[level].syntax == DQSYNTAX ||
1739		    state[level].syntax == ARISYNTAX)
1740			flags |= VSQUOTE;
1741		*(stackblock() + typeloc) = subtype | flags;
1742		if (subtype != VSNORMAL) {
1743			if (level + 1 >= maxnest) {
1744				maxnest *= 2;
1745				if (state == state_static) {
1746					state = parser_temp_alloc(
1747					    maxnest * sizeof(*state));
1748					memcpy(state, state_static,
1749					    MAXNEST_static * sizeof(*state));
1750				} else
1751					state = parser_temp_realloc(state,
1752					    maxnest * sizeof(*state));
1753			}
1754			level++;
1755			state[level].parenlevel = 0;
1756			if (subtype == VSMINUS || subtype == VSPLUS ||
1757			    subtype == VSQUESTION || subtype == VSASSIGN) {
1758				/*
1759				 * For operators that were in the Bourne shell,
1760				 * inherit the double-quote state.
1761				 */
1762				state[level].syntax = state[level - 1].syntax;
1763				state[level].category = TSTATE_VAR_OLD;
1764			} else {
1765				/*
1766				 * The other operators take a pattern,
1767				 * so go to BASESYNTAX.
1768				 * Also, ' and " are now special, even
1769				 * in here documents.
1770				 */
1771				state[level].syntax = BASESYNTAX;
1772				state[level].category = TSTATE_VAR_NEW;
1773				newvarnest++;
1774			}
1775		}
1776	} else if (c == '\'' && state[level].syntax == BASESYNTAX) {
1777		/* $'cstylequotes' */
1778		USTPUTC(CTLQUOTEMARK, out);
1779		state[level].syntax = SQSYNTAX;
1780		sqiscstyle = 1;
1781	} else {
1782		USTPUTC('$', out);
1783		pungetc();
1784	}
1785	goto parsesub_return;
1786}
1787
1788
1789/*
1790 * Parse an arithmetic expansion (indicate start of one and set state)
1791 */
1792parsearith: {
1793
1794	if (level + 1 >= maxnest) {
1795		maxnest *= 2;
1796		if (state == state_static) {
1797			state = parser_temp_alloc(
1798			    maxnest * sizeof(*state));
1799			memcpy(state, state_static,
1800			    MAXNEST_static * sizeof(*state));
1801		} else
1802			state = parser_temp_realloc(state,
1803			    maxnest * sizeof(*state));
1804	}
1805	level++;
1806	state[level].syntax = ARISYNTAX;
1807	state[level].parenlevel = 0;
1808	state[level].category = TSTATE_ARITH;
1809	USTPUTC(CTLARI, out);
1810	if (state[level - 1].syntax == DQSYNTAX)
1811		USTPUTC('"',out);
1812	else
1813		USTPUTC(' ',out);
1814	goto parsearith_return;
1815}
1816
1817} /* end of readtoken */
1818
1819
1820
1821#ifdef mkinit
1822RESET {
1823	tokpushback = 0;
1824	checkkwd = 0;
1825}
1826#endif
1827
1828/*
1829 * Returns true if the text contains nothing to expand (no dollar signs
1830 * or backquotes).
1831 */
1832
1833static int
1834noexpand(char *text)
1835{
1836	char *p;
1837	char c;
1838
1839	p = text;
1840	while ((c = *p++) != '\0') {
1841		if ( c == CTLQUOTEMARK)
1842			continue;
1843		if (c == CTLESC)
1844			p++;
1845		else if (BASESYNTAX[(int)c] == CCTL)
1846			return 0;
1847	}
1848	return 1;
1849}
1850
1851
1852/*
1853 * Return true if the argument is a legal variable name (a letter or
1854 * underscore followed by zero or more letters, underscores, and digits).
1855 */
1856
1857int
1858goodname(const char *name)
1859{
1860	const char *p;
1861
1862	p = name;
1863	if (! is_name(*p))
1864		return 0;
1865	while (*++p) {
1866		if (! is_in_name(*p))
1867			return 0;
1868	}
1869	return 1;
1870}
1871
1872
1873int
1874isassignment(const char *p)
1875{
1876	if (!is_name(*p))
1877		return 0;
1878	p++;
1879	for (;;) {
1880		if (*p == '=')
1881			return 1;
1882		else if (!is_in_name(*p))
1883			return 0;
1884		p++;
1885	}
1886}
1887
1888
1889/*
1890 * Called when an unexpected token is read during the parse.  The argument
1891 * is the token that is expected, or -1 if more than one type of token can
1892 * occur at this point.
1893 */
1894
1895static void
1896synexpect(int token)
1897{
1898	char msg[64];
1899
1900	if (token >= 0) {
1901		fmtstr(msg, 64, "%s unexpected (expecting %s)",
1902			tokname[lasttoken], tokname[token]);
1903	} else {
1904		fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
1905	}
1906	synerror(msg);
1907}
1908
1909
1910static void
1911synerror(const char *msg)
1912{
1913	if (commandname)
1914		outfmt(out2, "%s: %d: ", commandname, startlinno);
1915	outfmt(out2, "Syntax error: %s\n", msg);
1916	error((char *)NULL);
1917}
1918
1919static void
1920setprompt(int which)
1921{
1922	whichprompt = which;
1923
1924#ifndef NO_HISTORY
1925	if (!el)
1926#endif
1927	{
1928		out2str(getprompt(NULL));
1929		flushout(out2);
1930	}
1931}
1932
1933/*
1934 * called by editline -- any expansions to the prompt
1935 *    should be added here.
1936 */
1937char *
1938getprompt(void *unused __unused)
1939{
1940	static char ps[PROMPTLEN];
1941	char *fmt;
1942	const char *pwd;
1943	int i, trim;
1944	static char internal_error[] = "??";
1945
1946	/*
1947	 * Select prompt format.
1948	 */
1949	switch (whichprompt) {
1950	case 0:
1951		fmt = nullstr;
1952		break;
1953	case 1:
1954		fmt = ps1val();
1955		break;
1956	case 2:
1957		fmt = ps2val();
1958		break;
1959	default:
1960		return internal_error;
1961	}
1962
1963	/*
1964	 * Format prompt string.
1965	 */
1966	for (i = 0; (i < 127) && (*fmt != '\0'); i++, fmt++)
1967		if (*fmt == '\\')
1968			switch (*++fmt) {
1969
1970				/*
1971				 * Hostname.
1972				 *
1973				 * \h specifies just the local hostname,
1974				 * \H specifies fully-qualified hostname.
1975				 */
1976			case 'h':
1977			case 'H':
1978				ps[i] = '\0';
1979				gethostname(&ps[i], PROMPTLEN - i);
1980				/* Skip to end of hostname. */
1981				trim = (*fmt == 'h') ? '.' : '\0';
1982				while ((ps[i+1] != '\0') && (ps[i+1] != trim))
1983					i++;
1984				break;
1985
1986				/*
1987				 * Working directory.
1988				 *
1989				 * \W specifies just the final component,
1990				 * \w specifies the entire path.
1991				 */
1992			case 'W':
1993			case 'w':
1994				pwd = lookupvar("PWD");
1995				if (pwd == NULL)
1996					pwd = "?";
1997				if (*fmt == 'W' &&
1998				    *pwd == '/' && pwd[1] != '\0')
1999					strlcpy(&ps[i], strrchr(pwd, '/') + 1,
2000					    PROMPTLEN - i);
2001				else
2002					strlcpy(&ps[i], pwd, PROMPTLEN - i);
2003				/* Skip to end of path. */
2004				while (ps[i + 1] != '\0')
2005					i++;
2006				break;
2007
2008				/*
2009				 * Superuser status.
2010				 *
2011				 * '$' for normal users, '#' for root.
2012				 */
2013			case '$':
2014				ps[i] = (geteuid() != 0) ? '$' : '#';
2015				break;
2016
2017				/*
2018				 * A literal \.
2019				 */
2020			case '\\':
2021				ps[i] = '\\';
2022				break;
2023
2024				/*
2025				 * Emit unrecognized formats verbatim.
2026				 */
2027			default:
2028				ps[i++] = '\\';
2029				ps[i] = *fmt;
2030				break;
2031			}
2032		else
2033			ps[i] = *fmt;
2034	ps[i] = '\0';
2035	return (ps);
2036}
2037
2038
2039const char *
2040expandstr(char *ps)
2041{
2042	union node n;
2043	struct jmploc jmploc;
2044	struct jmploc *const savehandler = handler;
2045	const int saveprompt = doprompt;
2046	struct parsefile *const savetopfile = getcurrentfile();
2047	struct parser_temp *const saveparser_temp = parser_temp;
2048	const char *result = NULL;
2049
2050	if (!setjmp(jmploc.loc)) {
2051		handler = &jmploc;
2052		parser_temp = NULL;
2053		setinputstring(ps, 1);
2054		doprompt = 0;
2055		readtoken1(pgetc(), DQSYNTAX, "\n\n", 0);
2056		if (backquotelist != NULL)
2057			error("Command substitution not allowed here");
2058
2059		n.narg.type = NARG;
2060		n.narg.next = NULL;
2061		n.narg.text = wordtext;
2062		n.narg.backquote = backquotelist;
2063
2064		expandarg(&n, NULL, 0);
2065		result = stackblock();
2066		INTOFF;
2067	}
2068	handler = savehandler;
2069	doprompt = saveprompt;
2070	popfilesupto(savetopfile);
2071	if (parser_temp != saveparser_temp) {
2072		parser_temp_free_all();
2073		parser_temp = saveparser_temp;
2074	}
2075	if (result != NULL) {
2076		INTON;
2077	} else if (exception == EXINT)
2078		raise(SIGINT);
2079	return result;
2080}