BSD 4.4 Lite bin Sources

1 files changed, 1363 insertions, 0 deletions

diff --git a/bin/sh/parser.c b/bin/sh/parser.c
new file mode 100644
index 0000000..898349f
--- /dev/null
+++ b/bin/sh/parser.c
@@ -0,0 +1,1363 @@
+/*-
+ * 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. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. 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
+static char sccsid[] = "@(#)parser.c	8.1 (Berkeley) 5/31/93";
+#endif /* not lint */
+
+#include "shell.h"
+#include "parser.h"
+#include "nodes.h"
+#include "expand.h"	/* defines rmescapes() */
+#include "redir.h"	/* defines copyfd() */
+#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 "myhistedit.h"
+
+
+/*
+ * Shell command parser.
+ */
+
+#define EOFMARKLEN 79
+
+/* values returned by readtoken */
+#include "token.def"
+
+
+
+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 heredoc *heredoclist;	/* list of here documents to read */
+int parsebackquote;		/* nonzero if we are inside backquotes */
+int doprompt;			/* if set, prompt the user */
+int needprompt;			/* true if interactive and at start of line */
+int lasttoken;			/* last token read */
+MKINIT int tokpushback;		/* last token pushed back */
+char *wordtext;			/* text of last word returned by readtoken */
+MKINIT int checkkwd;            /* 1 == check for kwds, 2 == also eat newlines */
+struct nodelist *backquotelist;
+union node *redirnode;
+struct heredoc *heredoc;
+int quoteflag;			/* set if (part of) last token was quoted */
+int startlinno;			/* line # where last token started */
+
+
+#define GDB_HACK 1 /* avoid local declarations which gdb can't handle */
+#ifdef GDB_HACK
+static const char argvars[5] = {CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'};
+static const char types[] = "}-+?=";
+#endif
+
+
+STATIC union node *list __P((int));
+STATIC union node *andor __P((void));
+STATIC union node *pipeline __P((void));
+STATIC union node *command __P((void));
+STATIC union node *simplecmd __P((union node **, union node *));
+STATIC void parsefname __P((void));
+STATIC void parseheredoc __P((void));
+STATIC int readtoken __P((void));
+STATIC int readtoken1 __P((int, char const *, char *, int));
+STATIC void attyline __P((void));
+STATIC int noexpand __P((char *));
+STATIC void synexpect __P((int));
+STATIC void synerror __P((char *));
+STATIC void setprompt __P((int));
+
+/*
+ * Read and parse a command.  Returns NEOF on end of file.  (NULL is a
+ * valid parse tree indicating a blank line.)
+ */
+
+union node *
+parsecmd(interact) {
+	int t;
+
+	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);
+}
+
+
+STATIC union node *
+list(nlflag) {
+	union node *n1, *n2, *n3;
+
+	checkkwd = 2;
+	if (nlflag == 0 && tokendlist[peektoken()])
+		return NULL;
+	n1 = andor();
+	for (;;) {
+		switch (readtoken()) {
+		case TBACKGND:
+			if (n1->type == NCMD || n1->type == NPIPE) {
+				n1->ncmd.backgnd = 1;
+			} else if (n1->type == NREDIR) {
+				n1->type = NBACKGND;
+			} else {
+				n3 = (union node *)stalloc(sizeof (struct nredir));
+				n3->type = NBACKGND;
+				n3->nredir.n = n1;
+				n3->nredir.redirect = NULL;
+				n1 = n3;
+			}
+			goto tsemi;
+		case TNL:
+			tokpushback++;
+			/* fall through */
+tsemi:	    case TSEMI:
+			if (readtoken() == TNL) {
+				parseheredoc();
+				if (nlflag)
+					return n1;
+			} else {
+				tokpushback++;
+			}
+			checkkwd = 2;
+			if (tokendlist[peektoken()])
+				return n1;
+			n2 = andor();
+			n3 = (union node *)stalloc(sizeof (struct nbinary));
+			n3->type = NSEMI;
+			n3->nbinary.ch1 = n1;
+			n3->nbinary.ch2 = n2;
+			n1 = n3;
+			break;
+		case TEOF:
+			if (heredoclist)
+				parseheredoc();
+			else
+				pungetc();		/* push back EOF on input */
+			return n1;
+		default:
+			if (nlflag)
+				synexpect(-1);
+			tokpushback++;
+			return n1;
+		}
+	}
+}
+
+
+
+STATIC union node *
+andor() {
+	union node *n1, *n2, *n3;
+	int t;
+
+	n1 = pipeline();
+	for (;;) {
+		if ((t = readtoken()) == TAND) {
+			t = NAND;
+		} else if (t == TOR) {
+			t = NOR;
+		} else {
+			tokpushback++;
+			return n1;
+		}
+		n2 = pipeline();
+		n3 = (union node *)stalloc(sizeof (struct nbinary));
+		n3->type = t;
+		n3->nbinary.ch1 = n1;
+		n3->nbinary.ch2 = n2;
+		n1 = n3;
+	}
+}
+
+
+
+STATIC union node *
+pipeline() {
+	union node *n1, *pipenode, *notnode;
+	struct nodelist *lp, *prev;
+	int negate = 0;
+
+	TRACE(("pipeline: entered\n"));
+	while (readtoken() == TNOT) {
+		TRACE(("pipeline: TNOT recognized\n"));
+		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));
+			lp->n = command();
+			prev->next = lp;
+		} while (readtoken() == TPIPE);
+		lp->next = NULL;
+		n1 = pipenode;
+	}
+	tokpushback++;
+	if (negate) {
+		notnode = (union node *)stalloc(sizeof (struct nnot));
+		notnode->type = NNOT;
+		notnode->nnot.com = n1;
+		n1 = notnode;
+	}
+	return n1;
+}
+
+
+
+STATIC union node *
+command() {
+	union node *n1, *n2;
+	union node *ap, **app;
+	union node *cp, **cpp;
+	union node *redir, **rpp;
+	int t;
+
+	checkkwd = 2;
+	redir = 0;
+	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;
+		n1->nif.test = list(0);
+		if (readtoken() != TTHEN)
+			synexpect(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;
+			n2->nif.test = list(0);
+			if (readtoken() != TTHEN)
+				synexpect(TTHEN);
+			n2->nif.ifpart = list(0);
+		}
+		if (lasttoken == TELSE)
+			n2->nif.elsepart = list(0);
+		else {
+			n2->nif.elsepart = NULL;
+			tokpushback++;
+		}
+		if (readtoken() != TFI)
+			synexpect(TFI);
+		checkkwd = 1;
+		break;
+	case TWHILE:
+	case TUNTIL: {
+		int got;
+		n1 = (union node *)stalloc(sizeof (struct nbinary));
+		n1->type = (lasttoken == TWHILE)? NWHILE : NUNTIL;
+		n1->nbinary.ch1 = list(0);
+		if ((got=readtoken()) != TDO) {
+TRACE(("expecting DO got %s %s\n", tokname[got], got == TWORD ? wordtext : ""));
+			synexpect(TDO);
+		}
+		n1->nbinary.ch2 = list(0);
+		if (readtoken() != TDONE)
+			synexpect(TDONE);
+		checkkwd = 1;
+		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;
+		if (readtoken() == TWORD && ! quoteflag && equal(wordtext, "in")) {
+			app = ≈
+			while (readtoken() == TWORD) {
+				n2 = (union node *)stalloc(sizeof (struct narg));
+				n2->type = NARG;
+				n2->narg.text = wordtext;
+				n2->narg.backquote = backquotelist;
+				*app = n2;
+				app = &n2->narg.next;
+			}
+			*app = NULL;
+			n1->nfor.args = ap;
+			if (lasttoken != TNL && lasttoken != TSEMI)
+				synexpect(-1);
+		} else {
+#ifndef GDB_HACK
+			static const char argvars[5] = {CTLVAR, VSNORMAL|VSQUOTE,
+								   '@', '=', '\0'};
+#endif
+			n2 = (union node *)stalloc(sizeof (struct narg));
+			n2->type = NARG;
+			n2->narg.text = (char *)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 = 2;
+		if ((t = readtoken()) == TDO)
+			t = TDONE;
+		else if (t == TBEGIN)
+			t = TEND;
+		else
+			synexpect(-1);
+		n1->nfor.body = list(0);
+		if (readtoken() != t)
+			synexpect(t);
+		checkkwd = 1;
+		break;
+	case TCASE:
+		n1 = (union node *)stalloc(sizeof (struct ncase));
+		n1->type = NCASE;
+		if (readtoken() != TWORD)
+			synexpect(TWORD);
+		n1->ncase.expr = n2 = (union node *)stalloc(sizeof (struct narg));
+		n2->type = NARG;
+		n2->narg.text = wordtext;
+		n2->narg.backquote = backquotelist;
+		n2->narg.next = NULL;
+		while (readtoken() == TNL);
+		if (lasttoken != TWORD || ! equal(wordtext, "in"))
+			synerror("expecting \"in\"");
+		cpp = &n1->ncase.cases;
+		while (checkkwd = 2, readtoken() == TWORD) {
+			*cpp = cp = (union node *)stalloc(sizeof (struct nclist));
+			cp->type = NCLIST;
+			app = &cp->nclist.pattern;
+			for (;;) {
+				*app = ap = (union node *)stalloc(sizeof (struct narg));
+				ap->type = NARG;
+				ap->narg.text = wordtext;
+				ap->narg.backquote = backquotelist;
+				if (readtoken() != TPIPE)
+					break;
+				app = &ap->narg.next;
+				if (readtoken() != TWORD)
+					synexpect(TWORD);
+			}
+			ap->narg.next = NULL;
+			if (lasttoken != TRP)
+				synexpect(TRP);
+			cp->nclist.body = list(0);
+			if ((t = readtoken()) == TESAC)
+				tokpushback++;
+			else if (t != TENDCASE)
+				synexpect(TENDCASE);
+			cpp = &cp->nclist.next;
+		}
+		*cpp = NULL;
+		if (lasttoken != TESAC)
+			synexpect(TESAC);
+		checkkwd = 1;
+		break;
+	case TLP:
+		n1 = (union node *)stalloc(sizeof (struct nredir));
+		n1->type = NSUBSHELL;
+		n1->nredir.n = list(0);
+		n1->nredir.redirect = NULL;
+		if (readtoken() != TRP)
+			synexpect(TRP);
+		checkkwd = 1;
+		break;
+	case TBEGIN:
+		n1 = list(0);
+		if (readtoken() != TEND)
+			synexpect(TEND);
+		checkkwd = 1;
+		break;
+	/* Handle an empty command like other simple commands.  */
+	case TNL:
+	case TWORD:
+		tokpushback++;
+		return simplecmd(rpp, redir);
+	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 (n1->type != NSUBSHELL) {
+			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(rpp, redir) 
+	union node **rpp, *redir;
+	{
+	union node *args, **app;
+	union node **orig_rpp = rpp;
+	union node *n;
+
+	/* If we don't have any redirections already, then we must reset */
+	/* rpp to be the address of the local redir variable.  */
+	if (redir == 0)
+		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;
+
+	for (;;) {
+		if (readtoken() == TWORD) {
+			n = (union node *)stalloc(sizeof (struct narg));
+			n->type = NARG;
+			n->narg.text = wordtext;
+			n->narg.backquote = backquotelist;
+			*app = n;
+			app = &n->narg.next;
+		} 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 */
+			if (readtoken() != TRP)
+				synexpect(TRP);
+#ifdef notdef
+			if (! goodname(n->narg.text))
+				synerror("Bad function name");
+#endif
+			n->type = NDEFUN;
+			n->narg.next = command();
+			return n;
+		} else {
+			tokpushback++;
+			break;
+		}
+	}
+	*app = NULL;
+	*rpp = NULL;
+	n = (union node *)stalloc(sizeof (struct ncmd));
+	n->type = NCMD;
+	n->ncmd.backgnd = 0;
+	n->ncmd.args = args;
+	n->ncmd.redirect = redir;
+	return n;
+}
+
+
+STATIC void
+parsefname() {
+	union node *n = redirnode;
+
+	if (readtoken() != TWORD)
+		synexpect(-1);
+	if (n->type == NHERE) {
+		struct heredoc *here = heredoc;
+		struct heredoc *p;
+		int i;
+
+		if (quoteflag == 0)
+			n->type = NXHERE;
+		TRACE(("Here document %d\n", n->type));
+		if (here->striptabs) {
+			while (*wordtext == '\t')
+				wordtext++;
+		}
+		if (! noexpand(wordtext) || (i = strlen(wordtext)) == 0 || i > EOFMARKLEN)
+			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) {
+		if (is_digit(wordtext[0]))
+			n->ndup.dupfd = digit_val(wordtext[0]);
+		else if (wordtext[0] == '-')
+			n->ndup.dupfd = -1;
+		else
+			goto bad;
+		if (wordtext[1] != '\0') {
+bad:
+			synerror("Bad fd number");
+		}
+	} else {
+		n->nfile.fname = (union node *)stalloc(sizeof (struct narg));
+		n = n->nfile.fname;
+		n->type = NARG;
+		n->narg.next = NULL;
+		n->narg.text = wordtext;
+		n->narg.backquote = backquotelist;
+	}
+}
+
+
+/*
+ * Input any here documents.
+ */
+
+STATIC void
+parseheredoc() {
+	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 = (union node *)stalloc(sizeof (struct narg));
+		n->narg.type = NARG;
+		n->narg.next = NULL;
+		n->narg.text = wordtext;
+		n->narg.backquote = backquotelist;
+		here->here->nhere.doc = n;
+	}
+}
+
+STATIC int
+peektoken() {
+	int t;
+
+	t = readtoken();
+	tokpushback++;
+	return (t);
+}
+
+STATIC int xxreadtoken();
+
+STATIC int
+readtoken() {
+	int t;
+	int savecheckkwd = checkkwd;
+	struct alias *ap;
+#ifdef DEBUG
+	int alreadyseen = tokpushback;
+#endif
+	
+	top:
+	t = xxreadtoken();
+
+	if (checkkwd) {
+		/*
+		 * eat newlines
+		 */
+		if (checkkwd == 2) {
+			checkkwd = 0;
+			while (t == TNL) {
+				parseheredoc();
+				t = xxreadtoken();
+			}
+		} else
+			checkkwd = 0;
+		/*
+		 * check for keywords and aliases
+		 */
+		if (t == TWORD && !quoteflag) {
+			register char * const *pp, *s;
+
+			for (pp = (char **)parsekwd; *pp; pp++) {
+				if (**pp == *wordtext && equal(*pp, wordtext)) {
+					lasttoken = t = pp - parsekwd + KWDOFFSET;
+					TRACE(("keyword %s recognized\n", tokname[t]));
+					goto out;
+				}
+			}
+			if (ap = lookupalias(wordtext, 1)) {
+				pushstring(ap->val, strlen(ap->val), ap);
+				checkkwd = savecheckkwd;
+				goto top;
+			}
+		}
+out:
+		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() {
+	register 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();
+		if (c == ' ' || c == '\t')
+			continue;		/* quick check for white space first */
+		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();
+			goto breakloop;
+		case '\n':
+			plinno++;
+			needprompt = doprompt;
+			RETURN(TNL);
+		case PEOF:
+			RETURN(TEOF);
+		case '&':
+			if (pgetc() == '&')
+				RETURN(TAND);
+			pungetc();
+			RETURN(TBACKGND);
+		case '|':
+			if (pgetc() == '|')
+				RETURN(TOR);
+			pungetc();
+			RETURN(TPIPE);
+		case ';':
+			if (pgetc() == ';')
+				RETURN(TENDCASE);
+			pungetc();
+			RETURN(TSEMI);
+		case '(':
+			RETURN(TLP);
+		case ')':
+			RETURN(TRP);
+		default:
+			goto breakloop;
+		}
+	}
+breakloop:
+	return readtoken1(c, BASESYNTAX, (char *)NULL, 0);
+#undef RETURN
+}
+
+
+
+/*
+ * 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 CHECKEND()	{goto checkend; checkend_return:;}
+#define PARSEREDIR()	{goto parseredir; parseredir_return:;}
+#define PARSESUB()	{goto parsesub; parsesub_return:;}
+#define PARSEBACKQOLD()	{oldstyle = 1; goto parsebackq; parsebackq_oldreturn:;}
+#define PARSEBACKQNEW()	{oldstyle = 0; goto parsebackq; parsebackq_newreturn:;}
+#define	PARSEARITH()	{goto parsearith; parsearith_return:;}
+
+STATIC int
+readtoken1(firstc, syntax, eofmark, striptabs)
+	int firstc;
+	char const *syntax;
+	char *eofmark;
+	int striptabs;
+	{
+	register c = firstc;
+	register char *out;
+	int len;
+	char line[EOFMARKLEN + 1];
+	struct nodelist *bqlist;
+	int quotef;
+	int dblquote;
+	int varnest;	/* levels of variables expansion */
+	int arinest;	/* levels of arithmetic expansion */
+	int parenlevel;	/* levels of parens in arithmetic */
+	int oldstyle;
+	char const *prevsyntax;	/* syntax before arithmetic */
+
+	startlinno = plinno;
+	dblquote = 0;
+	if (syntax == DQSYNTAX)
+		dblquote = 1;
+	quotef = 0;
+	bqlist = NULL;
+	varnest = 0;
+	arinest = 0;
+	parenlevel = 0;
+
+	STARTSTACKSTR(out);
+	loop: {	/* for each line, until end of word */
+#if ATTY
+		if (c == '\034' && doprompt
+		 && attyset() && ! equal(termval(), "emacs")) {
+			attyline();
+			if (syntax == BASESYNTAX)
+				return readtoken();
+			c = pgetc();
+			goto loop;
+		}
+#endif
+		CHECKEND();	/* set c to PEOF if at end of here document */
+		for (;;) {	/* until end of line or end of word */
+			CHECKSTRSPACE(3, out);	/* permit 3 calls to USTPUTC */
+			if (parsebackquote && c == '\\') {
+				c = pgetc();	/* XXX - compat with old /bin/sh */
+				if (c != '\\' && c != '`' && c != '$') {
+					pungetc();
+					c = '\\';
+				}
+			}
+			switch(syntax[c]) {
+			case CNL:	/* '\n' */
+				if (syntax == BASESYNTAX)
+					goto endword;	/* exit outer loop */
+				USTPUTC(c, out);
+				plinno++;
+				if (doprompt)
+					setprompt(2);
+				else
+					setprompt(0);
+				c = pgetc();
+				goto loop;		/* continue outer loop */
+			case CWORD:
+				USTPUTC(c, out);
+				break;
+			case CCTL:
+				if (eofmark == NULL || dblquote)
+					USTPUTC(CTLESC, out);
+				USTPUTC(c, out);
+				break;
+			case CBACK:	/* backslash */
+				c = pgetc();
+				if (c == PEOF) {
+					USTPUTC('\\', out);
+					pungetc();
+				} else if (c == '\n') {
+					if (doprompt)
+						setprompt(2);
+					else
+						setprompt(0);
+				} else {
+					if (dblquote && c != '\\' && c != '`' && c != '$'
+							 && (c != '"' || eofmark != NULL))
+						USTPUTC('\\', out);
+					if (SQSYNTAX[c] == CCTL)
+						USTPUTC(CTLESC, out);
+					USTPUTC(c, out);
+					quotef++;
+				}
+				break;
+			case CSQUOTE:
+				syntax = SQSYNTAX;
+				break;
+			case CDQUOTE:
+				syntax = DQSYNTAX;
+				dblquote = 1;
+				break;
+			case CENDQUOTE:
+				if (eofmark) {
+					USTPUTC(c, out);
+				} else {
+					if (arinest)
+						syntax = ARISYNTAX;
+					else
+						syntax = BASESYNTAX;
+					quotef++;
+					dblquote = 0;
+				}
+				break;
+			case CVAR:	/* '$' */
+				PARSESUB();		/* parse substitution */
+				break;
+			case CENDVAR:	/* '}' */
+				if (varnest > 0) {
+					varnest--;
+					USTPUTC(CTLENDVAR, out);
+				} else {
+					USTPUTC(c, out);
+				}
+				break;
+			case CLP:	/* '(' in arithmetic */
+				parenlevel++;
+				USTPUTC(c, out);
+				break;
+			case CRP:	/* ')' in arithmetic */
+				if (parenlevel > 0) {
+					USTPUTC(c, out);
+					--parenlevel;
+				} else {
+					if (pgetc() == ')') {
+						if (--arinest == 0) {
+							USTPUTC(CTLENDARI, out);
+							syntax = prevsyntax;
+						} else
+							USTPUTC(')', out);
+					} else {
+						/* 
+						 * unbalanced parens
+						 *  (don't 2nd guess - no error)
+						 */
+						pungetc();
+						USTPUTC(')', out);
+					}
+				}
+				break;
+			case CBQUOTE:	/* '`' */
+				PARSEBACKQOLD();
+				break;
+			case CEOF:
+				goto endword;		/* exit outer loop */
+			default:
+				if (varnest == 0)
+					goto endword;	/* exit outer loop */
+				USTPUTC(c, out);
+			}
+			c = pgetc_macro();
+		}
+	}
+endword:
+	if (syntax == ARISYNTAX)
+		synerror("Missing '))'");
+	if (syntax != BASESYNTAX && ! parsebackquote && eofmark == NULL)
+		synerror("Unterminated quoted string");
+	if (varnest != 0) {
+		startlinno = plinno;
+		synerror("Missing '}'");
+	}
+	USTPUTC('\0', out);
+	len = out - stackblock();
+	out = stackblock();
+	if (eofmark == NULL) {
+		if ((c == '>' || c == '<')
+		 && quotef == 0
+		 && len <= 2
+		 && (*out == '\0' || is_digit(*out))) {
+			PARSEREDIR();
+			return lasttoken = TREDIR;
+		} else {
+			pungetc();
+		}
+	}
+	quoteflag = quotef;
+	backquotelist = bqlist;
+	grabstackblock(len);
+	wordtext = out;
+	return lasttoken = TWORD;
+/* end of readtoken routine */
+
+
+
+/*
+ * 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.
+ */
+
+checkend: {
+	if (eofmark) {
+		if (striptabs) {
+			while (c == '\t')
+				c = pgetc();
+		}
+		if (c == *eofmark) {
+			if (pfgets(line, sizeof line) != NULL) {
+				register char *p, *q;
+
+				p = line;
+				for (q = eofmark + 1 ; *q && *p == *q ; p++, q++);
+				if (*p == '\n' && *q == '\0') {
+					c = PEOF;
+					plinno++;
+					needprompt = doprompt;
+				} else {
+					pushstring(line, strlen(line), NULL);
+				}
+			}
+		}
+	}
+	goto checkend_return;
+}
+
+
+/*
+ * 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.
+ */
+
+parseredir: {
+	char fd = *out;
+	union node *np;
+
+	np = (union node *)stalloc(sizeof (struct nfile));
+	if (c == '>') {
+		np->nfile.fd = 1;
+		c = pgetc();
+		if (c == '>')
+			np->type = NAPPEND;
+		else if (c == '&')
+			np->type = NTOFD;
+		else {
+			np->type = NTO;
+			pungetc();
+		}
+	} else {	/* c == '<' */
+		np->nfile.fd = 0;
+		c = pgetc();
+		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()) == '-') {
+				heredoc->striptabs = 1;
+			} else {
+				heredoc->striptabs = 0;
+				pungetc();
+			}
+		} else if (c == '&')
+			np->type = NFROMFD;
+		else {
+			np->type = NFROM;
+			pungetc();
+		}
+	}
+	if (fd != '\0')
+		np->nfile.fd = digit_val(fd);
+	redirnode = np;
+	goto parseredir_return;
+}
+
+
+/*
+ * Parse a substitution.  At this point, we have read the dollar sign
+ * and nothing else.
+ */
+
+parsesub: {
+	int subtype;
+	int typeloc;
+	int flags;
+	char *p;
+#ifndef GDB_HACK
+	static const char types[] = "}-+?=";
+#endif
+
+	c = pgetc();
+	if (c != '(' && c != '{' && !is_name(c) && !is_special(c)) {
+		USTPUTC('$', out);
+		pungetc();
+	} else if (c == '(') {	/* $(command) or $((arith)) */
+		if (pgetc() == '(') {
+			PARSEARITH();
+		} else {
+			pungetc();
+			PARSEBACKQNEW();
+		}
+	} else {
+		USTPUTC(CTLVAR, out);
+		typeloc = out - stackblock();
+		USTPUTC(VSNORMAL, out);
+		subtype = VSNORMAL;
+		if (c == '{') {
+			c = pgetc();
+			subtype = 0;
+		}
+		if (is_name(c)) {
+			do {
+				STPUTC(c, out);
+				c = pgetc();
+			} while (is_in_name(c));
+		} else {
+			if (! is_special(c))
+badsub:				synerror("Bad substitution");
+			USTPUTC(c, out);
+			c = pgetc();
+		}
+		STPUTC('=', out);
+		flags = 0;
+		if (subtype == 0) {
+			if (c == ':') {
+				flags = VSNUL;
+				c = pgetc();
+			}
+			p = strchr(types, c);
+			if (p == NULL)
+				goto badsub;
+			subtype = p - types + VSNORMAL;
+		} else {
+			pungetc();
+		}
+		if (dblquote || arinest)
+			flags |= VSQUOTE;
+		*(stackblock() + typeloc) = subtype | flags;
+		if (subtype != VSNORMAL)
+			varnest++;
+	}
+	goto parsesub_return;
+}
+
+
+/*
+ * Called to parse command substitutions.  Newstyle is set if the command
+ * is enclosed inside $(...); nlpp is a pointer to the head of the linked
+ * list of commands (passed by reference), and savelen is the number of
+ * characters on the top of the stack which must be preserved.
+ */
+
+parsebackq: {
+	struct nodelist **nlpp;
+	int savepbq;
+	union node *n;
+	char *volatile str;
+	struct jmploc jmploc;
+	struct jmploc *volatile savehandler;
+	int savelen;
+
+	savepbq = parsebackquote;
+	if (setjmp(jmploc.loc)) {
+		if (str)
+			ckfree(str);
+		parsebackquote = 0;
+		handler = savehandler;
+		longjmp(handler->loc, 1);
+	}
+	INTOFF;
+	str = NULL;
+	savelen = out - stackblock();
+	if (savelen > 0) {
+		str = ckmalloc(savelen);
+		bcopy(stackblock(), str, savelen);
+	}
+	savehandler = handler;
+	handler = &jmploc;
+	INTON;
+        if (oldstyle) {
+                /* We must read until the closing backquote, giving special
+                   treatment to some slashes, and then push the string and
+                   reread it as input, interpreting it normally.  */
+                register char *out;
+                register c;
+                int savelen;
+                char *str;
+ 
+                STARTSTACKSTR(out);
+                while ((c = pgetc ()) != '`') {
+                       if (c == '\\') {
+                                c = pgetc ();
+                                if (c != '\\' && c != '`' && c != '$'
+                                    && (!dblquote || c != '"'))
+                                        STPUTC('\\', out);
+                       }
+                       STPUTC(c, out);
+                }
+                STPUTC('\0', out);
+                savelen = out - stackblock();
+                if (savelen > 0) {
+                        str = ckmalloc(savelen);
+                        bcopy(stackblock(), str, savelen);
+                }
+                setinputstring(str, 1);
+        }
+	nlpp = &bqlist;
+	while (*nlpp)
+		nlpp = &(*nlpp)->next;
+	*nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
+	(*nlpp)->next = NULL;
+	parsebackquote = oldstyle;
+	n = list(0);
+        if (!oldstyle && (readtoken() != TRP))
+                synexpect(TRP);
+	(*nlpp)->n = n;
+        /* Start reading from old file again.  */
+        if (oldstyle)
+                popfile();
+	while (stackblocksize() <= savelen)
+		growstackblock();
+	STARTSTACKSTR(out);
+	if (str) {
+		bcopy(str, out, savelen);
+		STADJUST(savelen, out);
+		INTOFF;
+		ckfree(str);
+		str = NULL;
+		INTON;
+	}
+	parsebackquote = savepbq;
+	handler = savehandler;
+	if (arinest || dblquote)
+		USTPUTC(CTLBACKQ | CTLQUOTE, out);
+	else
+		USTPUTC(CTLBACKQ, out);
+	if (oldstyle)
+		goto parsebackq_oldreturn;
+	else
+		goto parsebackq_newreturn;
+}
+
+/*
+ * Parse an arithmetic expansion (indicate start of one and set state)
+ */
+parsearith: {
+
+	if (++arinest == 1) {
+		prevsyntax = syntax;
+		syntax = ARISYNTAX;
+		USTPUTC(CTLARI, out);
+	} else {
+		/*
+		 * we collapse embedded arithmetic expansion to
+		 * parenthesis, which should be equivalent
+		 */
+		USTPUTC('(', out);
+	}
+	goto parsearith_return;
+}
+
+} /* end of readtoken */
+
+
+
+#ifdef mkinit
+RESET {
+	tokpushback = 0;
+	checkkwd = 0;
+}
+#endif
+
+/*
+ * Returns true if the text contains nothing to expand (no dollar signs
+ * or backquotes).
+ */
+
+STATIC int
+noexpand(text)
+	char *text;
+	{
+	register char *p;
+	register char c;
+
+	p = text;
+	while ((c = *p++) != '\0') {
+		if (c == CTLESC)
+			p++;
+		else if (BASESYNTAX[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(name)
+	char *name;
+	{
+	register char *p;
+
+	p = name;
+	if (! is_name(*p))
+		return 0;
+	while (*++p) {
+		if (! is_in_name(*p))
+			return 0;
+	}
+	return 1;
+}
+
+
+/*
+ * 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(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(msg)
+	char *msg;
+	{
+	if (commandname)
+		outfmt(&errout, "%s: %d: ", commandname, startlinno);
+	outfmt(&errout, "Syntax error: %s\n", msg);
+	error((char *)NULL);
+}
+
+STATIC void
+setprompt(which)
+	int which;
+	{
+	whichprompt = which;
+
+	if (!el)
+		out2str(getprompt(NULL));
+}
+
+/*
+ * called by editline -- any expansions to the prompt
+ *    should be added here.
+ */
+char *
+getprompt(unused)
+	void *unused;
+	{
+	switch (whichprompt) {
+	case 0:
+		return "";
+	case 1:
+		return ps1val();
+	case 2:
+		return ps2val();
+	default:
+		return "<internal prompt error>";
+	}
+}