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-rw-r--r--bin/1sh/parser.c2122
1 files changed, 2122 insertions, 0 deletions
diff --git a/bin/1sh/parser.c b/bin/1sh/parser.c
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--- /dev/null
+++ b/bin/1sh/parser.c
@@ -0,0 +1,2122 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)parser.c	8.7 (Berkeley) 5/16/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: releng/12.1/bin/sh/parser.c 334008 2018-05-21 21:52:48Z jilles $");
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+
+#include "shell.h"
+#include "parser.h"
+#include "nodes.h"
+#include "expand.h"	/* defines rmescapes() */
+#include "syntax.h"
+#include "options.h"
+#include "input.h"
+#include "output.h"
+#include "var.h"
+#include "error.h"
+#include "memalloc.h"
+#include "mystring.h"
+#include "alias.h"
+#include "show.h"
+#include "eval.h"
+#include "exec.h"	/* to check for special builtins */
+#ifndef NO_HISTORY
+#include "myhistedit.h"
+#endif
+
+/*
+ * Shell command parser.
+ */
+
+#define	PROMPTLEN	128
+
+/* values of checkkwd variable */
+#define CHKALIAS	0x1
+#define CHKKWD		0x2
+#define CHKNL		0x4
+
+/* values returned by readtoken */
+#include "token.h"
+
+
+
+struct heredoc {
+	struct heredoc *next;	/* next here document in list */
+	union node *here;		/* redirection node */
+	char *eofmark;		/* string indicating end of input */
+	int striptabs;		/* if set, strip leading tabs */
+};
+
+struct parser_temp {
+	struct parser_temp *next;
+	void *data;
+};
+
+
+static struct heredoc *heredoclist;	/* list of here documents to read */
+static int doprompt;		/* if set, prompt the user */
+static int needprompt;		/* true if interactive and at start of line */
+static int lasttoken;		/* last token read */
+static int tokpushback;		/* last token pushed back */
+static char *wordtext;		/* text of last word returned by readtoken */
+static int checkkwd;
+static struct nodelist *backquotelist;
+static union node *redirnode;
+static struct heredoc *heredoc;
+static int quoteflag;		/* set if (part of) last token was quoted */
+static int startlinno;		/* line # where last token started */
+static int funclinno;		/* line # where the current function started */
+static struct parser_temp *parser_temp;
+
+#define NOEOFMARK ((const char *)&heredoclist)
+
+
+static union node *list(int);
+static union node *andor(void);
+static union node *pipeline(void);
+static union node *command(void);
+static union node *simplecmd(union node **, union node *);
+static union node *makename(void);
+static union node *makebinary(int type, union node *n1, union node *n2);
+static void parsefname(void);
+static void parseheredoc(void);
+static int peektoken(void);
+static int readtoken(void);
+static int xxreadtoken(void);
+static int readtoken1(int, const char *, const char *, int);
+static int noexpand(char *);
+static void consumetoken(int);
+static void synexpect(int) __dead2;
+static void synerror(const char *) __dead2;
+static void setprompt(int);
+static int pgetc_linecont(void);
+
+
+static void *
+parser_temp_alloc(size_t len)
+{
+	struct parser_temp *t;
+
+	INTOFF;
+	t = ckmalloc(sizeof(*t));
+	t->data = NULL;
+	t->next = parser_temp;
+	parser_temp = t;
+	t->data = ckmalloc(len);
+	INTON;
+	return t->data;
+}
+
+
+static void *
+parser_temp_realloc(void *ptr, size_t len)
+{
+	struct parser_temp *t;
+
+	INTOFF;
+	t = parser_temp;
+	if (ptr != t->data)
+		error("bug: parser_temp_realloc misused");
+	t->data = ckrealloc(t->data, len);
+	INTON;
+	return t->data;
+}
+
+
+static void
+parser_temp_free_upto(void *ptr)
+{
+	struct parser_temp *t;
+	int done = 0;
+
+	INTOFF;
+	while (parser_temp != NULL && !done) {
+		t = parser_temp;
+		parser_temp = t->next;
+		done = t->data == ptr;
+		ckfree(t->data);
+		ckfree(t);
+	}
+	INTON;
+	if (!done)
+		error("bug: parser_temp_free_upto misused");
+}
+
+
+static void
+parser_temp_free_all(void)
+{
+	struct parser_temp *t;
+
+	INTOFF;
+	while (parser_temp != NULL) {
+		t = parser_temp;
+		parser_temp = t->next;
+		ckfree(t->data);
+		ckfree(t);
+	}
+	INTON;
+}
+
+
+/*
+ * Read and parse a command.  Returns NEOF on end of file.  (NULL is a
+ * valid parse tree indicating a blank line.)
+ */
+
+union node *
+parsecmd(int interact)
+{
+	int t;
+
+	/* This assumes the parser is not re-entered,
+	 * which could happen if we add command substitution on PS1/PS2.
+	 */
+	parser_temp_free_all();
+	heredoclist = NULL;
+
+	tokpushback = 0;
+	checkkwd = 0;
+	doprompt = interact;
+	if (doprompt)
+		setprompt(1);
+	else
+		setprompt(0);
+	needprompt = 0;
+	t = readtoken();
+	if (t == TEOF)
+		return NEOF;
+	if (t == TNL)
+		return NULL;
+	tokpushback++;
+	return list(1);
+}
+
+
+/*
+ * Read and parse words for wordexp.
+ * Returns a list of NARG nodes; NULL if there are no words.
+ */
+union node *
+parsewordexp(void)
+{
+	union node *n, *first = NULL, **pnext;
+	int t;
+
+	/* This assumes the parser is not re-entered,
+	 * which could happen if we add command substitution on PS1/PS2.
+	 */
+	parser_temp_free_all();
+	heredoclist = NULL;
+
+	tokpushback = 0;
+	checkkwd = 0;
+	doprompt = 0;
+	setprompt(0);
+	needprompt = 0;
+	pnext = &first;
+	while ((t = readtoken()) != TEOF) {
+		if (t != TWORD)
+			synexpect(TWORD);
+		n = makename();
+		*pnext = n;
+		pnext = &n->narg.next;
+	}
+	return first;
+}
+
+
+static union node *
+list(int nlflag)
+{
+	union node *ntop, *n1, *n2, *n3;
+	int tok;
+
+	checkkwd = CHKNL | CHKKWD | CHKALIAS;
+	if (!nlflag && tokendlist[peektoken()])
+		return NULL;
+	ntop = n1 = NULL;
+	for (;;) {
+		n2 = andor();
+		tok = readtoken();
+		if (tok == TBACKGND) {
+			if (n2 != NULL && n2->type == NPIPE) {
+				n2->npipe.backgnd = 1;
+			} else if (n2 != NULL && n2->type == NREDIR) {
+				n2->type = NBACKGND;
+			} else {
+				n3 = (union node *)stalloc(sizeof (struct nredir));
+				n3->type = NBACKGND;
+				n3->nredir.n = n2;
+				n3->nredir.redirect = NULL;
+				n2 = n3;
+			}
+		}
+		if (ntop == NULL)
+			ntop = n2;
+		else if (n1 == NULL) {
+			n1 = makebinary(NSEMI, ntop, n2);
+			ntop = n1;
+		}
+		else {
+			n3 = makebinary(NSEMI, n1->nbinary.ch2, n2);
+			n1->nbinary.ch2 = n3;
+			n1 = n3;
+		}
+		switch (tok) {
+		case TBACKGND:
+		case TSEMI:
+			tok = readtoken();
+			/* FALLTHROUGH */
+		case TNL:
+			if (tok == TNL) {
+				parseheredoc();
+				if (nlflag)
+					return ntop;
+			} else if (tok == TEOF && nlflag) {
+				parseheredoc();
+				return ntop;
+			} else {
+				tokpushback++;
+			}
+			checkkwd = CHKNL | CHKKWD | CHKALIAS;
+			if (!nlflag && tokendlist[peektoken()])
+				return ntop;
+			break;
+		case TEOF:
+			if (heredoclist)
+				parseheredoc();
+			else
+				pungetc();		/* push back EOF on input */
+			return ntop;
+		default:
+			if (nlflag)
+				synexpect(-1);
+			tokpushback++;
+			return ntop;
+		}
+	}
+}
+
+
+
+static union node *
+andor(void)
+{
+	union node *n;
+	int t;
+
+	n = pipeline();
+	for (;;) {
+		if ((t = readtoken()) == TAND) {
+			t = NAND;
+		} else if (t == TOR) {
+			t = NOR;
+		} else {
+			tokpushback++;
+			return n;
+		}
+		n = makebinary(t, n, pipeline());
+	}
+}
+
+
+
+static union node *
+pipeline(void)
+{
+	union node *n1, *n2, *pipenode;
+	struct nodelist *lp, *prev;
+	int negate, t;
+
+	negate = 0;
+	checkkwd = CHKNL | CHKKWD | CHKALIAS;
+	TRACE(("pipeline: entered\n"));
+	while (readtoken() == TNOT)
+		negate = !negate;
+	tokpushback++;
+	n1 = command();
+	if (readtoken() == TPIPE) {
+		pipenode = (union node *)stalloc(sizeof (struct npipe));
+		pipenode->type = NPIPE;
+		pipenode->npipe.backgnd = 0;
+		lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
+		pipenode->npipe.cmdlist = lp;
+		lp->n = n1;
+		do {
+			prev = lp;
+			lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
+			checkkwd = CHKNL | CHKKWD | CHKALIAS;
+			t = readtoken();
+			tokpushback++;
+			if (t == TNOT)
+				lp->n = pipeline();
+			else
+				lp->n = command();
+			prev->next = lp;
+		} while (readtoken() == TPIPE);
+		lp->next = NULL;
+		n1 = pipenode;
+	}
+	tokpushback++;
+	if (negate) {
+		n2 = (union node *)stalloc(sizeof (struct nnot));
+		n2->type = NNOT;
+		n2->nnot.com = n1;
+		return n2;
+	} else
+		return n1;
+}
+
+
+
+static union node *
+command(void)
+{
+	union node *n1, *n2;
+	union node *ap, **app;
+	union node *cp, **cpp;
+	union node *redir, **rpp;
+	int t;
+	int is_subshell;
+
+	checkkwd = CHKNL | CHKKWD | CHKALIAS;
+	is_subshell = 0;
+	redir = NULL;
+	n1 = NULL;
+	rpp = &redir;
+
+	/* Check for redirection which may precede command */
+	while (readtoken() == TREDIR) {
+		*rpp = n2 = redirnode;
+		rpp = &n2->nfile.next;
+		parsefname();
+	}
+	tokpushback++;
+
+	switch (readtoken()) {
+	case TIF:
+		n1 = (union node *)stalloc(sizeof (struct nif));
+		n1->type = NIF;
+		if ((n1->nif.test = list(0)) == NULL)
+			synexpect(-1);
+		consumetoken(TTHEN);
+		n1->nif.ifpart = list(0);
+		n2 = n1;
+		while (readtoken() == TELIF) {
+			n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
+			n2 = n2->nif.elsepart;
+			n2->type = NIF;
+			if ((n2->nif.test = list(0)) == NULL)
+				synexpect(-1);
+			consumetoken(TTHEN);
+			n2->nif.ifpart = list(0);
+		}
+		if (lasttoken == TELSE)
+			n2->nif.elsepart = list(0);
+		else {
+			n2->nif.elsepart = NULL;
+			tokpushback++;
+		}
+		consumetoken(TFI);
+		checkkwd = CHKKWD | CHKALIAS;
+		break;
+	case TWHILE:
+	case TUNTIL:
+		t = lasttoken;
+		if ((n1 = list(0)) == NULL)
+			synexpect(-1);
+		consumetoken(TDO);
+		n1 = makebinary((t == TWHILE)? NWHILE : NUNTIL, n1, list(0));
+		consumetoken(TDONE);
+		checkkwd = CHKKWD | CHKALIAS;
+		break;
+	case TFOR:
+		if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
+			synerror("Bad for loop variable");
+		n1 = (union node *)stalloc(sizeof (struct nfor));
+		n1->type = NFOR;
+		n1->nfor.var = wordtext;
+		while (readtoken() == TNL)
+			;
+		if (lasttoken == TWORD && ! quoteflag && equal(wordtext, "in")) {
+			app = &ap;
+			while (readtoken() == TWORD) {
+				n2 = makename();
+				*app = n2;
+				app = &n2->narg.next;
+			}
+			*app = NULL;
+			n1->nfor.args = ap;
+			if (lasttoken != TNL && lasttoken != TSEMI)
+				synexpect(-1);
+		} else {
+			static char argvars[5] = {
+				CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'
+			};
+			n2 = (union node *)stalloc(sizeof (struct narg));
+			n2->type = NARG;
+			n2->narg.text = argvars;
+			n2->narg.backquote = NULL;
+			n2->narg.next = NULL;
+			n1->nfor.args = n2;
+			/*
+			 * Newline or semicolon here is optional (but note
+			 * that the original Bourne shell only allowed NL).
+			 */
+			if (lasttoken != TNL && lasttoken != TSEMI)
+				tokpushback++;
+		}
+		checkkwd = CHKNL | CHKKWD | CHKALIAS;
+		if ((t = readtoken()) == TDO)
+			t = TDONE;
+		else if (t == TBEGIN)
+			t = TEND;
+		else
+			synexpect(-1);
+		n1->nfor.body = list(0);
+		consumetoken(t);
+		checkkwd = CHKKWD | CHKALIAS;
+		break;
+	case TCASE:
+		n1 = (union node *)stalloc(sizeof (struct ncase));
+		n1->type = NCASE;
+		consumetoken(TWORD);
+		n1->ncase.expr = makename();
+		while (readtoken() == TNL);
+		if (lasttoken != TWORD || ! equal(wordtext, "in"))
+			synerror("expecting \"in\"");
+		cpp = &n1->ncase.cases;
+		checkkwd = CHKNL | CHKKWD, readtoken();
+		while (lasttoken != TESAC) {
+			*cpp = cp = (union node *)stalloc(sizeof (struct nclist));
+			cp->type = NCLIST;
+			app = &cp->nclist.pattern;
+			if (lasttoken == TLP)
+				readtoken();
+			for (;;) {
+				*app = ap = makename();
+				checkkwd = CHKNL | CHKKWD;
+				if (readtoken() != TPIPE)
+					break;
+				app = &ap->narg.next;
+				readtoken();
+			}
+			ap->narg.next = NULL;
+			if (lasttoken != TRP)
+				synexpect(TRP);
+			cp->nclist.body = list(0);
+
+			checkkwd = CHKNL | CHKKWD | CHKALIAS;
+			if ((t = readtoken()) != TESAC) {
+				if (t == TENDCASE)
+					;
+				else if (t == TFALLTHRU)
+					cp->type = NCLISTFALLTHRU;
+				else
+					synexpect(TENDCASE);
+				checkkwd = CHKNL | CHKKWD, readtoken();
+			}
+			cpp = &cp->nclist.next;
+		}
+		*cpp = NULL;
+		checkkwd = CHKKWD | CHKALIAS;
+		break;
+	case TLP:
+		n1 = (union node *)stalloc(sizeof (struct nredir));
+		n1->type = NSUBSHELL;
+		n1->nredir.n = list(0);
+		n1->nredir.redirect = NULL;
+		consumetoken(TRP);
+		checkkwd = CHKKWD | CHKALIAS;
+		is_subshell = 1;
+		break;
+	case TBEGIN:
+		n1 = list(0);
+		consumetoken(TEND);
+		checkkwd = CHKKWD | CHKALIAS;
+		break;
+	/* A simple command must have at least one redirection or word. */
+	case TBACKGND:
+	case TSEMI:
+	case TAND:
+	case TOR:
+	case TPIPE:
+	case TENDCASE:
+	case TFALLTHRU:
+	case TEOF:
+	case TNL:
+	case TRP:
+		if (!redir)
+			synexpect(-1);
+	case TWORD:
+		tokpushback++;
+		n1 = simplecmd(rpp, redir);
+		return n1;
+	default:
+		synexpect(-1);
+	}
+
+	/* Now check for redirection which may follow command */
+	while (readtoken() == TREDIR) {
+		*rpp = n2 = redirnode;
+		rpp = &n2->nfile.next;
+		parsefname();
+	}
+	tokpushback++;
+	*rpp = NULL;
+	if (redir) {
+		if (!is_subshell) {
+			n2 = (union node *)stalloc(sizeof (struct nredir));
+			n2->type = NREDIR;
+			n2->nredir.n = n1;
+			n1 = n2;
+		}
+		n1->nredir.redirect = redir;
+	}
+
+	return n1;
+}
+
+
+static union node *
+simplecmd(union node **rpp, union node *redir)
+{
+	union node *args, **app;
+	union node **orig_rpp = rpp;
+	union node *n = NULL;
+	int special;
+	int savecheckkwd;
+
+	/* If we don't have any redirections already, then we must reset */
+	/* rpp to be the address of the local redir variable.  */
+	if (redir == NULL)
+		rpp = &redir;
+
+	args = NULL;
+	app = &args;
+	/*
+	 * We save the incoming value, because we need this for shell
+	 * functions.  There can not be a redirect or an argument between
+	 * the function name and the open parenthesis.
+	 */
+	orig_rpp = rpp;
+
+	savecheckkwd = CHKALIAS;
+
+	for (;;) {
+		checkkwd = savecheckkwd;
+		if (readtoken() == TWORD) {
+			n = makename();
+			*app = n;
+			app = &n->narg.next;
+			if (savecheckkwd != 0 && !isassignment(wordtext))
+				savecheckkwd = 0;
+		} else if (lasttoken == TREDIR) {
+			*rpp = n = redirnode;
+			rpp = &n->nfile.next;
+			parsefname();	/* read name of redirection file */
+		} else if (lasttoken == TLP && app == &args->narg.next
+					    && rpp == orig_rpp) {
+			/* We have a function */
+			consumetoken(TRP);
+			funclinno = plinno;
+			/*
+			 * - Require plain text.
+			 * - Functions with '/' cannot be called.
+			 * - Reject name=().
+			 * - Reject ksh extended glob patterns.
+			 */
+			if (!noexpand(n->narg.text) || quoteflag ||
+			    strchr(n->narg.text, '/') ||
+			    strchr("!%*+-=?@}~",
+				n->narg.text[strlen(n->narg.text) - 1]))
+				synerror("Bad function name");
+			rmescapes(n->narg.text);
+			if (find_builtin(n->narg.text, &special) >= 0 &&
+			    special)
+				synerror("Cannot override a special builtin with a function");
+			n->type = NDEFUN;
+			n->narg.next = command();
+			funclinno = 0;
+			return n;
+		} else {
+			tokpushback++;
+			break;
+		}
+	}
+	*app = NULL;
+	*rpp = NULL;
+	n = (union node *)stalloc(sizeof (struct ncmd));
+	n->type = NCMD;
+	n->ncmd.args = args;
+	n->ncmd.redirect = redir;
+	return n;
+}
+
+static union node *
+makename(void)
+{
+	union node *n;
+
+	n = (union node *)stalloc(sizeof (struct narg));
+	n->type = NARG;
+	n->narg.next = NULL;
+	n->narg.text = wordtext;
+	n->narg.backquote = backquotelist;
+	return n;
+}
+
+static union node *
+makebinary(int type, union node *n1, union node *n2)
+{
+	union node *n;
+
+	n = (union node *)stalloc(sizeof (struct nbinary));
+	n->type = type;
+	n->nbinary.ch1 = n1;
+	n->nbinary.ch2 = n2;
+	return (n);
+}
+
+void
+forcealias(void)
+{
+	checkkwd |= CHKALIAS;
+}
+
+void
+fixredir(union node *n, const char *text, int err)
+{
+	TRACE(("Fix redir %s %d\n", text, err));
+	if (!err)
+		n->ndup.vname = NULL;
+
+	if (is_digit(text[0]) && text[1] == '\0')
+		n->ndup.dupfd = digit_val(text[0]);
+	else if (text[0] == '-' && text[1] == '\0')
+		n->ndup.dupfd = -1;
+	else {
+
+		if (err)
+			synerror("Bad fd number");
+		else
+			n->ndup.vname = makename();
+	}
+}
+
+
+static void
+parsefname(void)
+{
+	union node *n = redirnode;
+
+	consumetoken(TWORD);
+	if (n->type == NHERE) {
+		struct heredoc *here = heredoc;
+		struct heredoc *p;
+
+		if (quoteflag == 0)
+			n->type = NXHERE;
+		TRACE(("Here document %d\n", n->type));
+		if (here->striptabs) {
+			while (*wordtext == '\t')
+				wordtext++;
+		}
+		if (! noexpand(wordtext))
+			synerror("Illegal eof marker for << redirection");
+		rmescapes(wordtext);
+		here->eofmark = wordtext;
+		here->next = NULL;
+		if (heredoclist == NULL)
+			heredoclist = here;
+		else {
+			for (p = heredoclist ; p->next ; p = p->next);
+			p->next = here;
+		}
+	} else if (n->type == NTOFD || n->type == NFROMFD) {
+		fixredir(n, wordtext, 0);
+	} else {
+		n->nfile.fname = makename();
+	}
+}
+
+
+/*
+ * Input any here documents.
+ */
+
+static void
+parseheredoc(void)
+{
+	struct heredoc *here;
+	union node *n;
+
+	while (heredoclist) {
+		here = heredoclist;
+		heredoclist = here->next;
+		if (needprompt) {
+			setprompt(2);
+			needprompt = 0;
+		}
+		readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
+				here->eofmark, here->striptabs);
+		n = makename();
+		here->here->nhere.doc = n;
+	}
+}
+
+static int
+peektoken(void)
+{
+	int t;
+
+	t = readtoken();
+	tokpushback++;
+	return (t);
+}
+
+static int
+readtoken(void)
+{
+	int t;
+	struct alias *ap;
+#ifdef DEBUG
+	int alreadyseen = tokpushback;
+#endif
+
+	top:
+	t = xxreadtoken();
+
+	/*
+	 * eat newlines
+	 */
+	if (checkkwd & CHKNL) {
+		while (t == TNL) {
+			parseheredoc();
+			t = xxreadtoken();
+		}
+	}
+
+	/*
+	 * check for keywords and aliases
+	 */
+	if (t == TWORD && !quoteflag)
+	{
+		const char * const *pp;
+
+		if (checkkwd & CHKKWD)
+			for (pp = parsekwd; *pp; pp++) {
+				if (**pp == *wordtext && equal(*pp, wordtext))
+				{
+					lasttoken = t = pp - parsekwd + KWDOFFSET;
+					TRACE(("keyword %s recognized\n", tokname[t]));
+					goto out;
+				}
+			}
+		if (checkkwd & CHKALIAS &&
+		    (ap = lookupalias(wordtext, 1)) != NULL) {
+			pushstring(ap->val, strlen(ap->val), ap);
+			goto top;
+		}
+	}
+out:
+	if (t != TNOT)
+		checkkwd = 0;
+
+#ifdef DEBUG
+	if (!alreadyseen)
+	    TRACE(("token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
+	else
+	    TRACE(("reread token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
+#endif
+	return (t);
+}
+
+
+/*
+ * Read the next input token.
+ * If the token is a word, we set backquotelist to the list of cmds in
+ *	backquotes.  We set quoteflag to true if any part of the word was
+ *	quoted.
+ * If the token is TREDIR, then we set redirnode to a structure containing
+ *	the redirection.
+ * In all cases, the variable startlinno is set to the number of the line
+ *	on which the token starts.
+ *
+ * [Change comment:  here documents and internal procedures]
+ * [Readtoken shouldn't have any arguments.  Perhaps we should make the
+ *  word parsing code into a separate routine.  In this case, readtoken
+ *  doesn't need to have any internal procedures, but parseword does.
+ *  We could also make parseoperator in essence the main routine, and
+ *  have parseword (readtoken1?) handle both words and redirection.]
+ */
+
+#define RETURN(token)	return lasttoken = token
+
+static int
+xxreadtoken(void)
+{
+	int c;
+
+	if (tokpushback) {
+		tokpushback = 0;
+		return lasttoken;
+	}
+	if (needprompt) {
+		setprompt(2);
+		needprompt = 0;
+	}
+	startlinno = plinno;
+	for (;;) {	/* until token or start of word found */
+		c = pgetc_macro();
+		switch (c) {
+		case ' ': case '\t':
+			continue;
+		case '#':
+			while ((c = pgetc()) != '\n' && c != PEOF);
+			pungetc();
+			continue;
+		case '\\':
+			if (pgetc() == '\n') {
+				startlinno = ++plinno;
+				if (doprompt)
+					setprompt(2);
+				else
+					setprompt(0);
+				continue;
+			}
+			pungetc();
+			/* FALLTHROUGH */
+		default:
+			return readtoken1(c, BASESYNTAX, (char *)NULL, 0);
+		case '\n':
+			plinno++;
+			needprompt = doprompt;
+			RETURN(TNL);
+		case PEOF:
+			RETURN(TEOF);
+		case '&':
+			if (pgetc_linecont() == '&')
+				RETURN(TAND);
+			pungetc();
+			RETURN(TBACKGND);
+		case '|':
+			if (pgetc_linecont() == '|')
+				RETURN(TOR);
+			pungetc();
+			RETURN(TPIPE);
+		case ';':
+			c = pgetc_linecont();
+			if (c == ';')
+				RETURN(TENDCASE);
+			else if (c == '&')
+				RETURN(TFALLTHRU);
+			pungetc();
+			RETURN(TSEMI);
+		case '(':
+			RETURN(TLP);
+		case ')':
+			RETURN(TRP);
+		}
+	}
+#undef RETURN
+}
+
+
+#define MAXNEST_static 8
+struct tokenstate
+{
+	const char *syntax; /* *SYNTAX */
+	int parenlevel; /* levels of parentheses in arithmetic */
+	enum tokenstate_category
+	{
+		TSTATE_TOP,
+		TSTATE_VAR_OLD, /* ${var+-=?}, inherits dquotes */
+		TSTATE_VAR_NEW, /* other ${var...}, own dquote state */
+		TSTATE_ARITH
+	} category;
+};
+
+
+/*
+ * Check to see whether we are at the end of the here document.  When this
+ * is called, c is set to the first character of the next input line.  If
+ * we are at the end of the here document, this routine sets the c to PEOF.
+ * The new value of c is returned.
+ */
+
+static int
+checkend(int c, const char *eofmark, int striptabs)
+{
+	if (striptabs) {
+		while (c == '\t')
+			c = pgetc();
+	}
+	if (c == *eofmark) {
+		int c2;
+		const char *q;
+
+		for (q = eofmark + 1; c2 = pgetc(), *q != '\0' && c2 == *q; q++)
+			;
+		if ((c2 == PEOF || c2 == '\n') && *q == '\0') {
+			c = PEOF;
+			if (c2 == '\n') {
+				plinno++;
+				needprompt = doprompt;
+			}
+		} else {
+			pungetc();
+			pushstring(eofmark + 1, q - (eofmark + 1), NULL);
+		}
+	} else if (c == '\n' && *eofmark == '\0') {
+		c = PEOF;
+		plinno++;
+		needprompt = doprompt;
+	}
+	return (c);
+}
+
+
+/*
+ * Parse a redirection operator.  The variable "out" points to a string
+ * specifying the fd to be redirected.  The variable "c" contains the
+ * first character of the redirection operator.
+ */
+
+static void
+parseredir(char *out, int c)
+{
+	char fd = *out;
+	union node *np;
+
+	np = (union node *)stalloc(sizeof (struct nfile));
+	if (c == '>') {
+		np->nfile.fd = 1;
+		c = pgetc_linecont();
+		if (c == '>')
+			np->type = NAPPEND;
+		else if (c == '&')
+			np->type = NTOFD;
+		else if (c == '|')
+			np->type = NCLOBBER;
+		else {
+			np->type = NTO;
+			pungetc();
+		}
+	} else {	/* c == '<' */
+		np->nfile.fd = 0;
+		c = pgetc_linecont();
+		if (c == '<') {
+			if (sizeof (struct nfile) != sizeof (struct nhere)) {
+				np = (union node *)stalloc(sizeof (struct nhere));
+				np->nfile.fd = 0;
+			}
+			np->type = NHERE;
+			heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
+			heredoc->here = np;
+			if ((c = pgetc_linecont()) == '-') {
+				heredoc->striptabs = 1;
+			} else {
+				heredoc->striptabs = 0;
+				pungetc();
+			}
+		} else if (c == '&')
+			np->type = NFROMFD;
+		else if (c == '>')
+			np->type = NFROMTO;
+		else {
+			np->type = NFROM;
+			pungetc();
+		}
+	}
+	if (fd != '\0')
+		np->nfile.fd = digit_val(fd);
+	redirnode = np;
+}
+
+/*
+ * Called to parse command substitutions.
+ */
+
+static char *
+parsebackq(char *out, struct nodelist **pbqlist,
+		int oldstyle, int dblquote, int quoted)
+{
+	struct nodelist **nlpp;
+	union node *n;
+	char *volatile str;
+	struct jmploc jmploc;
+	struct jmploc *const savehandler = handler;
+	size_t savelen;
+	int saveprompt;
+	const int bq_startlinno = plinno;
+	char *volatile ostr = NULL;
+	struct parsefile *const savetopfile = getcurrentfile();
+	struct heredoc *const saveheredoclist = heredoclist;
+	struct heredoc *here;
+
+	str = NULL;
+	if (setjmp(jmploc.loc)) {
+		popfilesupto(savetopfile);
+		if (str)
+			ckfree(str);
+		if (ostr)
+			ckfree(ostr);
+		heredoclist = saveheredoclist;
+		handler = savehandler;
+		if (exception == EXERROR) {
+			startlinno = bq_startlinno;
+			synerror("Error in command substitution");
+		}
+		longjmp(handler->loc, 1);
+	}
+	INTOFF;
+	savelen = out - stackblock();
+	if (savelen > 0) {
+		str = ckmalloc(savelen);
+		memcpy(str, stackblock(), savelen);
+	}
+	handler = &jmploc;
+	heredoclist = NULL;
+	INTON;
+        if (oldstyle) {
+                /* We must read until the closing backquote, giving special
+                   treatment to some slashes, and then push the string and
+                   reread it as input, interpreting it normally.  */
+                char *oout;
+                int c;
+                int olen;
+
+
+                STARTSTACKSTR(oout);
+		for (;;) {
+			if (needprompt) {
+				setprompt(2);
+				needprompt = 0;
+			}
+			CHECKSTRSPACE(2, oout);
+			c = pgetc_linecont();
+			if (c == '`')
+				break;
+			switch (c) {
+			case '\\':
+				c = pgetc();
+                                if (c != '\\' && c != '`' && c != '$'
+                                    && (!dblquote || c != '"'))
+                                        USTPUTC('\\', oout);
+				break;
+
+			case '\n':
+				plinno++;
+				needprompt = doprompt;
+				break;
+
+			case PEOF:
+			        startlinno = plinno;
+				synerror("EOF in backquote substitution");
+ 				break;
+
+			default:
+				break;
+			}
+			USTPUTC(c, oout);
+                }
+                USTPUTC('\0', oout);
+                olen = oout - stackblock();
+		INTOFF;
+		ostr = ckmalloc(olen);
+		memcpy(ostr, stackblock(), olen);
+		setinputstring(ostr, 1);
+		INTON;
+        }
+	nlpp = pbqlist;
+	while (*nlpp)
+		nlpp = &(*nlpp)->next;
+	*nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
+	(*nlpp)->next = NULL;
+
+	if (oldstyle) {
+		saveprompt = doprompt;
+		doprompt = 0;
+	}
+
+	n = list(0);
+
+	if (oldstyle) {
+		if (peektoken() != TEOF)
+			synexpect(-1);
+		doprompt = saveprompt;
+	} else
+		consumetoken(TRP);
+
+	(*nlpp)->n = n;
+        if (oldstyle) {
+		/*
+		 * Start reading from old file again, ignoring any pushed back
+		 * tokens left from the backquote parsing
+		 */
+                popfile();
+		tokpushback = 0;
+	}
+	STARTSTACKSTR(out);
+	CHECKSTRSPACE(savelen + 1, out);
+	INTOFF;
+	if (str) {
+		memcpy(out, str, savelen);
+		STADJUST(savelen, out);
+		ckfree(str);
+		str = NULL;
+	}
+	if (ostr) {
+		ckfree(ostr);
+		ostr = NULL;
+	}
+	here = saveheredoclist;
+	if (here != NULL) {
+		while (here->next != NULL)
+			here = here->next;
+		here->next = heredoclist;
+		heredoclist = saveheredoclist;
+	}
+	handler = savehandler;
+	INTON;
+	if (quoted)
+		USTPUTC(CTLBACKQ | CTLQUOTE, out);
+	else
+		USTPUTC(CTLBACKQ, out);
+	return out;
+}
+
+
+/*
+ * Called to parse a backslash escape sequence inside $'...'.
+ * The backslash has already been read.
+ */
+static char *
+readcstyleesc(char *out)
+{
+	int c, vc, i, n;
+	unsigned int v;
+
+	c = pgetc();
+	switch (c) {
+	case '\0':
+		synerror("Unterminated quoted string");
+	case '\n':
+		plinno++;
+		if (doprompt)
+			setprompt(2);
+		else
+			setprompt(0);
+		return out;
+	case '\\':
+	case '\'':
+	case '"':
+		v = c;
+		break;
+	case 'a': v = '\a'; break;
+	case 'b': v = '\b'; break;
+	case 'e': v = '\033'; break;
+	case 'f': v = '\f'; break;
+	case 'n': v = '\n'; break;
+	case 'r': v = '\r'; break;
+	case 't': v = '\t'; break;
+	case 'v': v = '\v'; break;
+	case 'x':
+		  v = 0;
+		  for (;;) {
+			  c = pgetc();
+			  if (c >= '0' && c <= '9')
+				  v = (v << 4) + c - '0';
+			  else if (c >= 'A' && c <= 'F')
+				  v = (v << 4) + c - 'A' + 10;
+			  else if (c >= 'a' && c <= 'f')
+				  v = (v << 4) + c - 'a' + 10;
+			  else
+				  break;
+		  }
+		  pungetc();
+		  break;
+	case '0': case '1': case '2': case '3':
+	case '4': case '5': case '6': case '7':
+		  v = c - '0';
+		  c = pgetc();
+		  if (c >= '0' && c <= '7') {
+			  v <<= 3;
+			  v += c - '0';
+			  c = pgetc();
+			  if (c >= '0' && c <= '7') {
+				  v <<= 3;
+				  v += c - '0';
+			  } else
+				  pungetc();
+		  } else
+			  pungetc();
+		  break;
+	case 'c':
+		  c = pgetc();
+		  if (c < 0x3f || c > 0x7a || c == 0x60)
+			  synerror("Bad escape sequence");
+		  if (c == '\\' && pgetc() != '\\')
+			  synerror("Bad escape sequence");
+		  if (c == '?')
+			  v = 127;
+		  else
+			  v = c & 0x1f;
+		  break;
+	case 'u':
+	case 'U':
+		  n = c == 'U' ? 8 : 4;
+		  v = 0;
+		  for (i = 0; i < n; i++) {
+			  c = pgetc();
+			  if (c >= '0' && c <= '9')
+				  v = (v << 4) + c - '0';
+			  else if (c >= 'A' && c <= 'F')
+				  v = (v << 4) + c - 'A' + 10;
+			  else if (c >= 'a' && c <= 'f')
+				  v = (v << 4) + c - 'a' + 10;
+			  else
+				  synerror("Bad escape sequence");
+		  }
+		  if (v == 0 || (v >= 0xd800 && v <= 0xdfff))
+			  synerror("Bad escape sequence");
+		  /* We really need iconv here. */
+		  if (initial_localeisutf8 && v > 127) {
+			  CHECKSTRSPACE(4, out);
+			  /*
+			   * We cannot use wctomb() as the locale may have
+			   * changed.
+			   */
+			  if (v <= 0x7ff) {
+				  USTPUTC(0xc0 | v >> 6, out);
+				  USTPUTC(0x80 | (v & 0x3f), out);
+				  return out;
+			  } else if (v <= 0xffff) {
+				  USTPUTC(0xe0 | v >> 12, out);
+				  USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
+				  USTPUTC(0x80 | (v & 0x3f), out);
+				  return out;
+			  } else if (v <= 0x10ffff) {
+				  USTPUTC(0xf0 | v >> 18, out);
+				  USTPUTC(0x80 | ((v >> 12) & 0x3f), out);
+				  USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
+				  USTPUTC(0x80 | (v & 0x3f), out);
+				  return out;
+			  }
+		  }
+		  if (v > 127)
+			  v = '?';
+		  break;
+	default:
+		  synerror("Bad escape sequence");
+	}
+	vc = (char)v;
+	/*
+	 * We can't handle NUL bytes.
+	 * POSIX says we should skip till the closing quote.
+	 */
+	if (vc == '\0') {
+		while ((c = pgetc()) != '\'') {
+			if (c == '\\')
+				c = pgetc();
+			if (c == PEOF)
+				synerror("Unterminated quoted string");
+			if (c == '\n') {
+				plinno++;
+				if (doprompt)
+					setprompt(2);
+				else
+					setprompt(0);
+			}
+		}
+		pungetc();
+		return out;
+	}
+	if (SQSYNTAX[vc] == CCTL)
+		USTPUTC(CTLESC, out);
+	USTPUTC(vc, out);
+	return out;
+}
+
+
+/*
+ * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
+ * is not NULL, read a here document.  In the latter case, eofmark is the
+ * word which marks the end of the document and striptabs is true if
+ * leading tabs should be stripped from the document.  The argument firstc
+ * is the first character of the input token or document.
+ *
+ * Because C does not have internal subroutines, I have simulated them
+ * using goto's to implement the subroutine linkage.  The following macros
+ * will run code that appears at the end of readtoken1.
+ */
+
+#define PARSESUB()	{goto parsesub; parsesub_return:;}
+#define	PARSEARITH()	{goto parsearith; parsearith_return:;}
+
+static int
+readtoken1(int firstc, char const *initialsyntax, const char *eofmark,
+    int striptabs)
+{
+	int c = firstc;
+	char *out;
+	int len;
+	struct nodelist *bqlist;
+	int quotef;
+	int newvarnest;
+	int level;
+	int synentry;
+	struct tokenstate state_static[MAXNEST_static];
+	int maxnest = MAXNEST_static;
+	struct tokenstate *state = state_static;
+	int sqiscstyle = 0;
+
+	startlinno = plinno;
+	quotef = 0;
+	bqlist = NULL;
+	newvarnest = 0;
+	level = 0;
+	state[level].syntax = initialsyntax;
+	state[level].parenlevel = 0;
+	state[level].category = TSTATE_TOP;
+
+	STARTSTACKSTR(out);
+	loop: {	/* for each line, until end of word */
+		if (eofmark && eofmark != NOEOFMARK)
+			/* set c to PEOF if at end of here document */
+			c = checkend(c, eofmark, striptabs);
+		for (;;) {	/* until end of line or end of word */
+			CHECKSTRSPACE(4, out);	/* permit 4 calls to USTPUTC */
+
+			synentry = state[level].syntax[c];
+
+			switch(synentry) {
+			case CNL:	/* '\n' */
+				if (level == 0)
+					goto endword;	/* exit outer loop */
+				/* FALLTHROUGH */
+			case CQNL:
+				USTPUTC(c, out);
+				plinno++;
+				if (doprompt)
+					setprompt(2);
+				else
+					setprompt(0);
+				c = pgetc();
+				goto loop;		/* continue outer loop */
+			case CSBACK:
+				if (sqiscstyle) {
+					out = readcstyleesc(out);
+					break;
+				}
+				/* FALLTHROUGH */
+			case CWORD:
+				USTPUTC(c, out);
+				break;
+			case CCTL:
+				if (eofmark == NULL || initialsyntax != SQSYNTAX)
+					USTPUTC(CTLESC, out);
+				USTPUTC(c, out);
+				break;
+			case CBACK:	/* backslash */
+				c = pgetc();
+				if (c == PEOF) {
+					USTPUTC('\\', out);
+					pungetc();
+				} else if (c == '\n') {
+					plinno++;
+					if (doprompt)
+						setprompt(2);
+					else
+						setprompt(0);
+				} else {
+					if (state[level].syntax == DQSYNTAX &&
+					    c != '\\' && c != '`' && c != '$' &&
+					    (c != '"' || (eofmark != NULL &&
+						newvarnest == 0)) &&
+					    (c != '}' || state[level].category != TSTATE_VAR_OLD))
+						USTPUTC('\\', out);
+					if ((eofmark == NULL ||
+					    newvarnest > 0) &&
+					    state[level].syntax == BASESYNTAX)
+						USTPUTC(CTLQUOTEMARK, out);
+					if (SQSYNTAX[c] == CCTL)
+						USTPUTC(CTLESC, out);
+					USTPUTC(c, out);
+					if ((eofmark == NULL ||
+					    newvarnest > 0) &&
+					    state[level].syntax == BASESYNTAX &&
+					    state[level].category == TSTATE_VAR_OLD)
+						USTPUTC(CTLQUOTEEND, out);
+					quotef++;
+				}
+				break;
+			case CSQUOTE:
+				USTPUTC(CTLQUOTEMARK, out);
+				state[level].syntax = SQSYNTAX;
+				sqiscstyle = 0;
+				break;
+			case CDQUOTE:
+				USTPUTC(CTLQUOTEMARK, out);
+				state[level].syntax = DQSYNTAX;
+				break;
+			case CENDQUOTE:
+				if (eofmark != NULL && newvarnest == 0)
+					USTPUTC(c, out);
+				else {
+					if (state[level].category == TSTATE_VAR_OLD)
+						USTPUTC(CTLQUOTEEND, out);
+					state[level].syntax = BASESYNTAX;
+					quotef++;
+				}
+				break;
+			case CVAR:	/* '$' */
+				PARSESUB();		/* parse substitution */
+				break;
+			case CENDVAR:	/* '}' */
+				if (level > 0 &&
+				    ((state[level].category == TSTATE_VAR_OLD &&
+				      state[level].syntax ==
+				      state[level - 1].syntax) ||
+				    (state[level].category == TSTATE_VAR_NEW &&
+				     state[level].syntax == BASESYNTAX))) {
+					if (state[level].category == TSTATE_VAR_NEW)
+						newvarnest--;
+					level--;
+					USTPUTC(CTLENDVAR, out);
+				} else {
+					USTPUTC(c, out);
+				}
+				break;
+			case CLP:	/* '(' in arithmetic */
+				state[level].parenlevel++;
+				USTPUTC(c, out);
+				break;
+			case CRP:	/* ')' in arithmetic */
+				if (state[level].parenlevel > 0) {
+					USTPUTC(c, out);
+					--state[level].parenlevel;
+				} else {
+					if (pgetc_linecont() == ')') {
+						if (level > 0 &&
+						    state[level].category == TSTATE_ARITH) {
+							level--;
+							USTPUTC(CTLENDARI, out);
+						} else
+							USTPUTC(')', out);
+					} else {
+						/*
+						 * unbalanced parens
+						 *  (don't 2nd guess - no error)
+						 */
+						pungetc();
+						USTPUTC(')', out);
+					}
+				}
+				break;
+			case CBQUOTE:	/* '`' */
+				out = parsebackq(out, &bqlist, 1,
+				    state[level].syntax == DQSYNTAX &&
+				    (eofmark == NULL || newvarnest > 0),
+				    state[level].syntax == DQSYNTAX || state[level].syntax == ARISYNTAX);
+				break;
+			case CEOF:
+				goto endword;		/* exit outer loop */
+			case CIGN:
+				break;
+			default:
+				if (level == 0)
+					goto endword;	/* exit outer loop */
+				USTPUTC(c, out);
+			}
+			c = pgetc_macro();
+		}
+	}
+endword:
+	if (state[level].syntax == ARISYNTAX)
+		synerror("Missing '))'");
+	if (state[level].syntax != BASESYNTAX && eofmark == NULL)
+		synerror("Unterminated quoted string");
+	if (state[level].category == TSTATE_VAR_OLD ||
+	    state[level].category == TSTATE_VAR_NEW) {
+		startlinno = plinno;
+		synerror("Missing '}'");
+	}
+	if (state != state_static)
+		parser_temp_free_upto(state);
+	USTPUTC('\0', out);
+	len = out - stackblock();
+	out = stackblock();
+	if (eofmark == NULL) {
+		if ((c == '>' || c == '<')
+		 && quotef == 0
+		 && len <= 2
+		 && (*out == '\0' || is_digit(*out))) {
+			parseredir(out, c);
+			return lasttoken = TREDIR;
+		} else {
+			pungetc();
+		}
+	}
+	quoteflag = quotef;
+	backquotelist = bqlist;
+	grabstackblock(len);
+	wordtext = out;
+	return lasttoken = TWORD;
+/* end of readtoken routine */
+
+
+/*
+ * Parse a substitution.  At this point, we have read the dollar sign
+ * and nothing else.
+ */
+
+parsesub: {
+	int subtype;
+	int typeloc;
+	int flags;
+	char *p;
+	static const char types[] = "}-+?=";
+	int linno;
+	int length;
+	int c1;
+
+	c = pgetc_linecont();
+	if (c == '(') {	/* $(command) or $((arith)) */
+		if (pgetc_linecont() == '(') {
+			PARSEARITH();
+		} else {
+			pungetc();
+			out = parsebackq(out, &bqlist, 0,
+			    state[level].syntax == DQSYNTAX &&
+			    (eofmark == NULL || newvarnest > 0),
+			    state[level].syntax == DQSYNTAX ||
+			    state[level].syntax == ARISYNTAX);
+		}
+	} else if (c == '{' || is_name(c) || is_special(c)) {
+		USTPUTC(CTLVAR, out);
+		typeloc = out - stackblock();
+		USTPUTC(VSNORMAL, out);
+		subtype = VSNORMAL;
+		flags = 0;
+		if (c == '{') {
+			c = pgetc_linecont();
+			subtype = 0;
+		}
+varname:
+		if (!is_eof(c) && is_name(c)) {
+			length = 0;
+			do {
+				STPUTC(c, out);
+				c = pgetc_linecont();
+				length++;
+			} while (!is_eof(c) && is_in_name(c));
+			if (length == 6 &&
+			    strncmp(out - length, "LINENO", length) == 0) {
+				/* Replace the variable name with the
+				 * current line number. */
+				STADJUST(-6, out);
+				CHECKSTRSPACE(11, out);
+				linno = plinno;
+				if (funclinno != 0)
+					linno -= funclinno - 1;
+				length = snprintf(out, 11, "%d", linno);
+				if (length > 10)
+					length = 10;
+				out += length;
+				flags |= VSLINENO;
+			}
+		} else if (is_digit(c)) {
+			if (subtype != VSNORMAL) {
+				do {
+					STPUTC(c, out);
+					c = pgetc_linecont();
+				} while (is_digit(c));
+			} else {
+				USTPUTC(c, out);
+				c = pgetc_linecont();
+			}
+		} else if (is_special(c)) {
+			c1 = c;
+			c = pgetc_linecont();
+			if (subtype == 0 && c1 == '#') {
+				subtype = VSLENGTH;
+				if (strchr(types, c) == NULL && c != ':' &&
+				    c != '#' && c != '%')
+					goto varname;
+				c1 = c;
+				c = pgetc_linecont();
+				if (c1 != '}' && c == '}') {
+					pungetc();
+					c = c1;
+					goto varname;
+				}
+				pungetc();
+				c = c1;
+				c1 = '#';
+				subtype = 0;
+			}
+			USTPUTC(c1, out);
+		} else {
+			subtype = VSERROR;
+			if (c == '}')
+				pungetc();
+			else if (c == '\n' || c == PEOF)
+				synerror("Unexpected end of line in substitution");
+			else if (BASESYNTAX[c] != CCTL)
+				USTPUTC(c, out);
+		}
+		if (subtype == 0) {
+			switch (c) {
+			case ':':
+				flags |= VSNUL;
+				c = pgetc_linecont();
+				/*FALLTHROUGH*/
+			default:
+				p = strchr(types, c);
+				if (p == NULL) {
+					if (c == '\n' || c == PEOF)
+						synerror("Unexpected end of line in substitution");
+					if (flags == VSNUL)
+						STPUTC(':', out);
+					if (BASESYNTAX[c] != CCTL)
+						STPUTC(c, out);
+					subtype = VSERROR;
+				} else
+					subtype = p - types + VSNORMAL;
+				break;
+			case '%':
+			case '#':
+				{
+					int cc = c;
+					subtype = c == '#' ? VSTRIMLEFT :
+							     VSTRIMRIGHT;
+					c = pgetc_linecont();
+					if (c == cc)
+						subtype++;
+					else
+						pungetc();
+					break;
+				}
+			}
+		} else if (subtype != VSERROR) {
+			if (subtype == VSLENGTH && c != '}')
+				subtype = VSERROR;
+			pungetc();
+		}
+		STPUTC('=', out);
+		if (state[level].syntax == DQSYNTAX ||
+		    state[level].syntax == ARISYNTAX)
+			flags |= VSQUOTE;
+		*(stackblock() + typeloc) = subtype | flags;
+		if (subtype != VSNORMAL) {
+			if (level + 1 >= maxnest) {
+				maxnest *= 2;
+				if (state == state_static) {
+					state = parser_temp_alloc(
+					    maxnest * sizeof(*state));
+					memcpy(state, state_static,
+					    MAXNEST_static * sizeof(*state));
+				} else
+					state = parser_temp_realloc(state,
+					    maxnest * sizeof(*state));
+			}
+			level++;
+			state[level].parenlevel = 0;
+			if (subtype == VSMINUS || subtype == VSPLUS ||
+			    subtype == VSQUESTION || subtype == VSASSIGN) {
+				/*
+				 * For operators that were in the Bourne shell,
+				 * inherit the double-quote state.
+				 */
+				state[level].syntax = state[level - 1].syntax;
+				state[level].category = TSTATE_VAR_OLD;
+			} else {
+				/*
+				 * The other operators take a pattern,
+				 * so go to BASESYNTAX.
+				 * Also, ' and " are now special, even
+				 * in here documents.
+				 */
+				state[level].syntax = BASESYNTAX;
+				state[level].category = TSTATE_VAR_NEW;
+				newvarnest++;
+			}
+		}
+	} else if (c == '\'' && state[level].syntax == BASESYNTAX) {
+		/* $'cstylequotes' */
+		USTPUTC(CTLQUOTEMARK, out);
+		state[level].syntax = SQSYNTAX;
+		sqiscstyle = 1;
+	} else {
+		USTPUTC('$', out);
+		pungetc();
+	}
+	goto parsesub_return;
+}
+
+
+/*
+ * Parse an arithmetic expansion (indicate start of one and set state)
+ */
+parsearith: {
+
+	if (level + 1 >= maxnest) {
+		maxnest *= 2;
+		if (state == state_static) {
+			state = parser_temp_alloc(
+			    maxnest * sizeof(*state));
+			memcpy(state, state_static,
+			    MAXNEST_static * sizeof(*state));
+		} else
+			state = parser_temp_realloc(state,
+			    maxnest * sizeof(*state));
+	}
+	level++;
+	state[level].syntax = ARISYNTAX;
+	state[level].parenlevel = 0;
+	state[level].category = TSTATE_ARITH;
+	USTPUTC(CTLARI, out);
+	if (state[level - 1].syntax == DQSYNTAX)
+		USTPUTC('"',out);
+	else
+		USTPUTC(' ',out);
+	goto parsearith_return;
+}
+
+} /* end of readtoken */
+
+
+/*
+ * Returns true if the text contains nothing to expand (no dollar signs
+ * or backquotes).
+ */
+
+static int
+noexpand(char *text)
+{
+	char *p;
+	char c;
+
+	p = text;
+	while ((c = *p++) != '\0') {
+		if ( c == CTLQUOTEMARK)
+			continue;
+		if (c == CTLESC)
+			p++;
+		else if (BASESYNTAX[(int)c] == CCTL)
+			return 0;
+	}
+	return 1;
+}
+
+
+/*
+ * Return true if the argument is a legal variable name (a letter or
+ * underscore followed by zero or more letters, underscores, and digits).
+ */
+
+int
+goodname(const char *name)
+{
+	const char *p;
+
+	p = name;
+	if (! is_name(*p))
+		return 0;
+	while (*++p) {
+		if (! is_in_name(*p))
+			return 0;
+	}
+	return 1;
+}
+
+
+int
+isassignment(const char *p)
+{
+	if (!is_name(*p))
+		return 0;
+	p++;
+	for (;;) {
+		if (*p == '=')
+			return 1;
+		else if (!is_in_name(*p))
+			return 0;
+		p++;
+	}
+}
+
+
+static void
+consumetoken(int token)
+{
+	if (readtoken() != token)
+		synexpect(token);
+}
+
+
+/*
+ * Called when an unexpected token is read during the parse.  The argument
+ * is the token that is expected, or -1 if more than one type of token can
+ * occur at this point.
+ */
+
+static void
+synexpect(int token)
+{
+	char msg[64];
+
+	if (token >= 0) {
+		fmtstr(msg, 64, "%s unexpected (expecting %s)",
+			tokname[lasttoken], tokname[token]);
+	} else {
+		fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
+	}
+	synerror(msg);
+}
+
+
+static void
+synerror(const char *msg)
+{
+	if (commandname)
+		outfmt(out2, "%s: %d: ", commandname, startlinno);
+	else if (arg0)
+		outfmt(out2, "%s: ", arg0);
+	outfmt(out2, "Syntax error: %s\n", msg);
+	error((char *)NULL);
+}
+
+static void
+setprompt(int which)
+{
+	whichprompt = which;
+	if (which == 0)
+		return;
+
+#ifndef NO_HISTORY
+	if (!el)
+#endif
+	{
+		out2str(getprompt(NULL));
+		flushout(out2);
+	}
+}
+
+static int
+pgetc_linecont(void)
+{
+	int c;
+
+	while ((c = pgetc_macro()) == '\\') {
+		c = pgetc();
+		if (c == '\n') {
+			plinno++;
+			if (doprompt)
+				setprompt(2);
+			else
+				setprompt(0);
+		} else {
+			pungetc();
+			/* Allow the backslash to be pushed back. */
+			pushstring("\\", 1, NULL);
+			return (pgetc());
+		}
+	}
+	return (c);
+}
+
+/*
+ * called by editline -- any expansions to the prompt
+ *    should be added here.
+ */
+char *
+getprompt(void *unused __unused)
+{
+	static char ps[PROMPTLEN];
+	const char *fmt;
+	const char *pwd;
+	int i, trim;
+	static char internal_error[] = "??";
+
+	/*
+	 * Select prompt format.
+	 */
+	switch (whichprompt) {
+	case 0:
+		fmt = "";
+		break;
+	case 1:
+		fmt = ps1val();
+		break;
+	case 2:
+		fmt = ps2val();
+		break;
+	default:
+		return internal_error;
+	}
+
+	/*
+	 * Format prompt string.
+	 */
+	for (i = 0; (i < PROMPTLEN - 1) && (*fmt != '\0'); i++, fmt++)
+		if (*fmt == '\\')
+			switch (*++fmt) {
+
+				/*
+				 * Hostname.
+				 *
+				 * \h specifies just the local hostname,
+				 * \H specifies fully-qualified hostname.
+				 */
+			case 'h':
+			case 'H':
+				ps[i] = '\0';
+				gethostname(&ps[i], PROMPTLEN - i - 1);
+				ps[PROMPTLEN - 1] = '\0';
+				/* Skip to end of hostname. */
+				trim = (*fmt == 'h') ? '.' : '\0';
+				while ((ps[i] != '\0') && (ps[i] != trim))
+					i++;
+				--i;
+				break;
+
+				/*
+				 * Working directory.
+				 *
+				 * \W specifies just the final component,
+				 * \w specifies the entire path.
+				 */
+			case 'W':
+			case 'w':
+				pwd = lookupvar("PWD");
+				if (pwd == NULL || *pwd == '\0')
+					pwd = "?";
+				if (*fmt == 'W' &&
+				    *pwd == '/' && pwd[1] != '\0')
+					strlcpy(&ps[i], strrchr(pwd, '/') + 1,
+					    PROMPTLEN - i);
+				else
+					strlcpy(&ps[i], pwd, PROMPTLEN - i);
+				/* Skip to end of path. */
+				while (ps[i + 1] != '\0')
+					i++;
+				break;
+
+				/*
+				 * Superuser status.
+				 *
+				 * '$' for normal users, '#' for root.
+				 */
+			case '$':
+				ps[i] = (geteuid() != 0) ? '$' : '#';
+				break;
+
+				/*
+				 * A literal \.
+				 */
+			case '\\':
+				ps[i] = '\\';
+				break;
+
+				/*
+				 * Emit unrecognized formats verbatim.
+				 */
+			default:
+				ps[i] = '\\';
+				if (i < PROMPTLEN - 2)
+					ps[++i] = *fmt;
+				break;
+			}
+		else
+			ps[i] = *fmt;
+	ps[i] = '\0';
+	return (ps);
+}
+
+
+const char *
+expandstr(const char *ps)
+{
+	union node n;
+	struct jmploc jmploc;
+	struct jmploc *const savehandler = handler;
+	const int saveprompt = doprompt;
+	struct parsefile *const savetopfile = getcurrentfile();
+	struct parser_temp *const saveparser_temp = parser_temp;
+	const char *result = NULL;
+
+	if (!setjmp(jmploc.loc)) {
+		handler = &jmploc;
+		parser_temp = NULL;
+		setinputstring(ps, 1);
+		doprompt = 0;
+		readtoken1(pgetc(), DQSYNTAX, NOEOFMARK, 0);
+		if (backquotelist != NULL)
+			error("Command substitution not allowed here");
+
+		n.narg.type = NARG;
+		n.narg.next = NULL;
+		n.narg.text = wordtext;
+		n.narg.backquote = backquotelist;
+
+		expandarg(&n, NULL, 0);
+		result = stackblock();
+		INTOFF;
+	}
+	handler = savehandler;
+	doprompt = saveprompt;
+	popfilesupto(savetopfile);
+	if (parser_temp != saveparser_temp) {
+		parser_temp_free_all();
+		parser_temp = saveparser_temp;
+	}
+	if (result != NULL) {
+		INTON;
+	} else if (exception == EXINT)
+		raise(SIGINT);
+	return result;
+}