earlpy

6 files changed, 1804 insertions, 0 deletions

diff --git a/examples/check_errors.py b/examples/check_errors.py
new file mode 100644
index 0000000..70f9f13
--- /dev/null
+++ b/examples/check_errors.py
@@ -0,0 +1,14 @@
+import earlpy
+import sys
+
+p = earlpy.Parser("grammars/c")
+node = p.parse_file(sys.argv[1])
+node.print_tree()
+def visit(n):
+    if isinstance(n, earlpy.Token):
+        return
+    if n.symbol.name == "ERROR":
+        print(n.line_numbers(), n.pprint())
+    else:
+        for a in n.contents: visit(a)
+visit(node)
diff --git a/examples/dash_var.c b/examples/dash_var.c
new file mode 100644
index 0000000..b70d72c
--- /dev/null
+++ b/examples/dash_var.c
@@ -0,0 +1,678 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 1997-2005
+ *	Herbert Xu <herbert@gondor.apana.org.au>.  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.
+ */
+
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#ifdef HAVE_PATHS_H
+#include <paths.h>
+#endif
+
+/*
+ * Shell variables.
+ */
+
+#include "shell.h"
+#include "output.h"
+#include "expand.h"
+#include "nodes.h"	/* for other headers */
+#include "exec.h"
+#include "syntax.h"
+#include "options.h"
+#include "mail.h"
+#include "var.h"
+#include "memalloc.h"
+#include "error.h"
+#include "mystring.h"
+#include "parser.h"
+#include "show.h"
+#ifndef SMALL
+#include "myhistedit.h"
+#endif
+#include "system.h"
+
+
+#define VTABSIZE 39
+
+
+struct localvar_list {
+	struct localvar_list *next;
+	struct localvar *lv;
+};
+
+MKINIT struct localvar_list *localvar_stack;
+
+const char defpathvar[] =
+	"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin";
+char defifsvar[] = "IFS= \t\n";
+MKINIT char defoptindvar[] = "OPTIND=1";
+
+int lineno;
+char linenovar[sizeof("LINENO=")+sizeof(int)*CHAR_BIT/3+1] = "LINENO=";
+
+/* Some macros in var.h depend on the order, add new variables to the end. */
+struct var varinit[] = {
+#if ATTY
+	{ 0,	VSTRFIXED|VTEXTFIXED|VUNSET,	"ATTY\0",	0 },
+#endif
+	{ 0,	VSTRFIXED|VTEXTFIXED,		defifsvar,	0 },
+	{ 0,	VSTRFIXED|VTEXTFIXED|VUNSET,	"MAIL\0",	changemail },
+	{ 0,	VSTRFIXED|VTEXTFIXED|VUNSET,	"MAILPATH\0",	changemail },
+	{ 0,	VSTRFIXED|VTEXTFIXED,		defpathvar,	changepath },
+	{ 0,	VSTRFIXED|VTEXTFIXED,		"PS1=$ ",	0 },
+	{ 0,	VSTRFIXED|VTEXTFIXED,		"PS2=> ",	0 },
+	{ 0,	VSTRFIXED|VTEXTFIXED,		"PS4=+ ",	0 },
+	{ 0,	VSTRFIXED|VTEXTFIXED,		defoptindvar,	getoptsreset },
+#ifdef WITH_LINENO
+	{ 0,	VSTRFIXED|VTEXTFIXED,		linenovar,	0 },
+#endif
+#ifndef SMALL
+	{ 0,	VSTRFIXED|VTEXTFIXED|VUNSET,	"TERM\0",	0 },
+	{ 0,	VSTRFIXED|VTEXTFIXED|VUNSET,	"HISTSIZE\0",	sethistsize },
+#endif
+};
+
+STATIC struct var *vartab[VTABSIZE];
+
+STATIC struct var **hashvar(const char *);
+STATIC int vpcmp(const void *, const void *);
+STATIC struct var **findvar(struct var **, const char *);
+
+/*
+ * Initialize the varable symbol tables and import the environment
+ */
+
+#ifdef mkinit
+INCLUDE <unistd.h>
+INCLUDE <sys/types.h>
+INCLUDE <sys/stat.h>
+INCLUDE "cd.h"
+INCLUDE "output.h"
+INCLUDE "var.h"
+MKINIT char **environ;
+INIT {
+	char **envp;
+	static char ppid[32] = "PPID=";
+	const char *p;
+	struct stat64 st1, st2;
+
+	initvar();
+	for (envp = environ ; *envp ; envp++) {
+		p = endofname(*envp);
+		if (p != *envp && *p == '=') {
+			setvareq(*envp, VEXPORT|VTEXTFIXED);
+		}
+	}
+
+	setvareq(defifsvar, VTEXTFIXED);
+	setvareq(defoptindvar, VTEXTFIXED);
+
+	fmtstr(ppid + 5, sizeof(ppid) - 5, "%ld", (long) getppid());
+	setvareq(ppid, VTEXTFIXED);
+
+	p = lookupvar("PWD");
+	if (p)
+		if (*p != '/' || stat64(p, &st1) || stat64(".", &st2) ||
+		    st1.st_dev != st2.st_dev || st1.st_ino != st2.st_ino)
+			p = 0;
+	setpwd(p, 0);
+}
+
+RESET {
+	unwindlocalvars(0);
+}
+#endif
+
+static char *varnull(const char *s)
+{
+	return (strchr(s, '=') ?: nullstr - 1) + 1;
+}
+
+/*
+ * This routine initializes the builtin variables.  It is called when the
+ * shell is initialized.
+ */
+
+void
+initvar(void)
+{
+	struct var *vp;
+	struct var *end;
+	struct var **vpp;
+
+	vp = varinit;
+	end = vp + sizeof(varinit) / sizeof(varinit[0]);
+	do {
+		vpp = hashvar(vp->text);
+		vp->next = *vpp;
+		*vpp = vp;
+	} while (++vp < end);
+	/*
+	 * PS1 depends on uid
+	 */
+	if (!geteuid())
+		vps1.text = "PS1=# ";
+}
+
+/*
+ * Set the value of a variable.  The flags argument is ored with the
+ * flags of the variable.  If val is NULL, the variable is unset.
+ */
+
+struct var *setvar(const char *name, const char *val, int flags)
+{
+	char *p, *q;
+	size_t namelen;
+	char *nameeq;
+	size_t vallen;
+	struct var *vp;
+
+	q = endofname(name);
+	p = strchrnul(q, '=');
+	namelen = p - name;
+	if (!namelen || p != q)
+		sh_error("%.*s: bad variable name", namelen, name);
+	vallen = 0;
+	if (val == NULL) {
+		flags |= VUNSET;
+	} else {
+		vallen = strlen(val);
+	}
+	INTOFF;
+	p = mempcpy(nameeq = ckmalloc(namelen + vallen + 2), name, namelen);
+	if (val) {
+		*p++ = '=';
+		p = mempcpy(p, val, vallen);
+	}
+	*p = '\0';
+	vp = setvareq(nameeq, flags | VNOSAVE);
+	INTON;
+
+	return vp;
+}
+
+/*
+ * Set the given integer as the value of a variable.  The flags argument is
+ * ored with the flags of the variable.
+ */
+
+intmax_t setvarint(const char *name, intmax_t val, int flags)
+{
+	int len = max_int_length(sizeof(val));
+	char buf[len];
+
+	fmtstr(buf, len, "%" PRIdMAX, val);
+	setvar(name, buf, flags);
+	return val;
+}
+
+
+
+/*
+ * Same as setvar except that the variable and value are passed in
+ * the first argument as name=value.  Since the first argument will
+ * be actually stored in the table, it should not be a string that
+ * will go away.
+ * Called with interrupts off.
+ */
+
+struct var *setvareq(char *s, int flags)
+{
+	struct var *vp, **vpp;
+
+	vpp = hashvar(s);
+	flags |= (VEXPORT & (((unsigned) (1 - aflag)) - 1));
+	vpp = findvar(vpp, s);
+	vp = *vpp;
+	if (vp) {
+		if (vp->flags & VREADONLY) {
+			const char *n;
+
+			if (flags & VNOSAVE)
+				free(s);
+			n = vp->text;
+			sh_error("%.*s: is read only", strchrnul(n, '=') - n,
+				 n);
+		}
+
+		if (flags & VNOSET)
+			goto out;
+
+		if (vp->func && (flags & VNOFUNC) == 0)
+			(*vp->func)(varnull(s));
+
+		if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
+			ckfree(vp->text);
+
+		if (((flags & (VEXPORT|VREADONLY|VSTRFIXED|VUNSET)) |
+		     (vp->flags & VSTRFIXED)) == VUNSET) {
+			*vpp = vp->next;
+			ckfree(vp);
+out_free:
+			if ((flags & (VTEXTFIXED|VSTACK|VNOSAVE)) == VNOSAVE)
+				ckfree(s);
+			goto out;
+		}
+
+		flags |= vp->flags & ~(VTEXTFIXED|VSTACK|VNOSAVE|VUNSET);
+	} else {
+		if (flags & VNOSET)
+			goto out;
+		if ((flags & (VEXPORT|VREADONLY|VSTRFIXED|VUNSET)) == VUNSET)
+			goto out_free;
+		/* not found */
+		vp = ckmalloc(sizeof (*vp));
+		vp->next = *vpp;
+		vp->func = NULL;
+		*vpp = vp;
+	}
+	if (!(flags & (VTEXTFIXED|VSTACK|VNOSAVE)))
+		s = savestr(s);
+	vp->text = s;
+	vp->flags = flags;
+
+out:
+	return vp;
+}
+
+/*
+ * Find the value of a variable.  Returns NULL if not set.
+ */
+
+char *
+lookupvar(const char *name)
+{
+	struct var *v;
+
+	if ((v = *findvar(hashvar(name), name)) && !(v->flags & VUNSET)) {
+#ifdef WITH_LINENO
+		if (v == &vlineno && v->text == linenovar) {
+			fmtstr(linenovar+7, sizeof(linenovar)-7, "%d", lineno);
+		}
+#endif
+		return strchrnul(v->text, '=') + 1;
+	}
+	return NULL;
+}
+
+intmax_t lookupvarint(const char *name)
+{
+	return atomax(lookupvar(name) ?: nullstr, 0);
+}
+
+
+
+/*
+ * Generate a list of variables satisfying the given conditions.
+ */
+
+char **
+listvars(int on, int off, char ***end)
+{
+	struct var **vpp;
+	struct var *vp;
+	char **ep;
+	int mask;
+
+	STARTSTACKSTR(ep);
+	vpp = vartab;
+	mask = on | off;
+	do {
+		for (vp = *vpp ; vp ; vp = vp->next)
+			if ((vp->flags & mask) == on) {
+				if (ep == stackstrend())
+					ep = growstackstr();
+				*ep++ = (char *) vp->text;
+			}
+	} while (++vpp < vartab + VTABSIZE);
+	if (ep == stackstrend())
+		ep = growstackstr();
+	if (end)
+		*end = ep;
+	*ep++ = NULL;
+	return grabstackstr(ep);
+}
+
+
+
+/*
+ * POSIX requires that 'set' (but not export or readonly) output the
+ * variables in lexicographic order - by the locale's collating order (sigh).
+ * Maybe we could keep them in an ordered balanced binary tree
+ * instead of hashed lists.
+ * For now just roll 'em through qsort for printing...
+ */
+
+int
+showvars(const char *prefix, int on, int off)
+{
+	const char *sep;
+	char **ep, **epend;
+
+	ep = listvars(on, off, &epend);
+	qsort(ep, epend - ep, sizeof(char *), vpcmp);
+
+	sep = *prefix ? spcstr : prefix;
+
+	for (; ep < epend; ep++) {
+		const char *p;
+		const char *q;
+
+		p = strchrnul(*ep, '=');
+		q = nullstr;
+		if (*p)
+			q = single_quote(++p);
+
+		out1fmt("%s%s%.*s%s\n", prefix, sep, (int)(p - *ep), *ep, q);
+	}
+
+	return 0;
+}
+
+
+
+/*
+ * The export and readonly commands.
+ */
+
+int
+exportcmd(int argc, char **argv)
+{
+	struct var *vp;
+	char *name;
+	const char *p;
+	char **aptr;
+	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
+	int notp;
+
+	notp = nextopt("p") - 'p';
+	if (notp && ((name = *(aptr = argptr)))) {
+		do {
+			if ((p = strchr(name, '=')) != NULL) {
+				p++;
+			} else {
+				if ((vp = *findvar(hashvar(name), name))) {
+					vp->flags |= flag;
+					continue;
+				}
+			}
+			setvar(name, p, flag);
+		} while ((name = *++aptr) != NULL);
+	} else {
+		showvars(argv[0], flag, 0);
+	}
+	return 0;
+}
+
+
+/*
+ * The "local" command.
+ */
+
+int
+localcmd(int argc, char **argv)
+{
+	char *name;
+
+	if (!localvar_stack)
+		sh_error("not in a function");
+
+	argv = argptr;
+	while ((name = *argv++) != NULL) {
+		mklocal(name, 0);
+	}
+	return 0;
+}
+
+
+/*
+ * Make a variable a local variable.  When a variable is made local, it's
+ * value and flags are saved in a localvar structure.  The saved values
+ * will be restored when the shell function returns.  We handle the name
+ * "-" as a special case.
+ */
+
+void mklocal(char *name, int flags)
+{
+	struct localvar *lvp;
+	struct var **vpp;
+	struct var *vp;
+
+	INTOFF;
+	lvp = ckmalloc(sizeof (struct localvar));
+	if (name[0] == '-' && name[1] == '\0') {
+		char *p;
+		p = ckmalloc(sizeof(optlist));
+		lvp->text = memcpy(p, optlist, sizeof(optlist));
+		vp = NULL;
+	} else {
+		char *eq;
+
+		vpp = hashvar(name);
+		vp = *findvar(vpp, name);
+		eq = strchr(name, '=');
+		if (vp == NULL) {
+			if (eq)
+				vp = setvareq(name, VSTRFIXED | flags);
+			else
+				vp = setvar(name, NULL, VSTRFIXED | flags);
+			lvp->flags = VUNSET;
+		} else {
+			lvp->text = vp->text;
+			lvp->flags = vp->flags;
+			vp->flags |= VSTRFIXED|VTEXTFIXED;
+			if (eq)
+				setvareq(name, flags);
+		}
+	}
+	lvp->vp = vp;
+	lvp->next = localvar_stack->lv;
+	localvar_stack->lv = lvp;
+	INTON;
+}
+
+
+/*
+ * Called after a function returns.
+ * Interrupts must be off.
+ */
+
+static void
+poplocalvars(void)
+{
+	struct localvar_list *ll;
+	struct localvar *lvp, *next;
+	struct var *vp;
+
+	INTOFF;
+	ll = localvar_stack;
+	localvar_stack = ll->next;
+
+	next = ll->lv;
+	ckfree(ll);
+
+	while ((lvp = next) != NULL) {
+		next = lvp->next;
+		vp = lvp->vp;
+		TRACE(("poplocalvar %s\n", vp ? vp->text : "-"));
+		if (vp == NULL) {	/* $- saved */
+			memcpy(optlist, lvp->text, sizeof(optlist));
+			ckfree(lvp->text);
+			optschanged();
+		} else if (lvp->flags == VUNSET) {
+			vp->flags &= ~(VSTRFIXED|VREADONLY);
+			unsetvar(vp->text);
+		} else {
+			if (vp->func)
+				(*vp->func)(varnull(lvp->text));
+			if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
+				ckfree(vp->text);
+			vp->flags = lvp->flags;
+			vp->text = lvp->text;
+		}
+		ckfree(lvp);
+	}
+	INTON;
+}
+
+
+/*
+ * Create a new localvar environment.
+ */
+struct localvar_list *pushlocalvars(int push)
+{
+	struct localvar_list *ll;
+	struct localvar_list *top;
+
+	top = localvar_stack;
+	if (!push)
+		goto out;
+
+	INTOFF;
+	ll = ckmalloc(sizeof(*ll));
+	ll->lv = NULL;
+	ll->next = top;
+	localvar_stack = ll;
+	INTON;
+
+out:
+	return top;
+}
+
+
+void unwindlocalvars(struct localvar_list *stop)
+{
+	while (localvar_stack != stop)
+		poplocalvars();
+}
+
+
+/*
+ * The unset builtin command.  We unset the function before we unset the
+ * variable to allow a function to be unset when there is a readonly variable
+ * with the same name.
+ */
+
+int
+unsetcmd(int argc, char **argv)
+{
+	char **ap;
+	int i;
+	int flag = 0;
+
+	while ((i = nextopt("vf")) != '\0') {
+		flag = i;
+	}
+
+	for (ap = argptr; *ap ; ap++) {
+		if (flag != 'f') {
+			unsetvar(*ap);
+			continue;
+		}
+		if (flag != 'v')
+			unsetfunc(*ap);
+	}
+	return 0;
+}
+
+
+/*
+ * Unset the specified variable.
+ */
+
+void unsetvar(const char *s)
+{
+	setvar(s, 0, 0);
+}
+
+
+
+/*
+ * Find the appropriate entry in the hash table from the name.
+ */
+
+STATIC struct var **
+hashvar(const char *p)
+{
+	unsigned int hashval;
+
+	hashval = ((unsigned char) *p) << 4;
+	while (*p && *p != '=')
+		hashval += (unsigned char) *p++;
+	return &vartab[hashval % VTABSIZE];
+}
+
+
+
+/*
+ * Compares two strings up to the first = or '\0'.  The first
+ * string must be terminated by '='; the second may be terminated by
+ * either '=' or '\0'.
+ */
+
+int
+varcmp(const char *p, const char *q)
+{
+	int c, d;
+
+	while ((c = *p) == (d = *q)) {
+		if (!c || c == '=')
+			goto out;
+		p++;
+		q++;
+	}
+	if (c == '=')
+		c = 0;
+	if (d == '=')
+		d = 0;
+out:
+	return c - d;
+}
+
+STATIC int
+vpcmp(const void *a, const void *b)
+{
+	return varcmp(*(const char **)a, *(const char **)b);
+}
+
+STATIC struct var **
+findvar(struct var **vpp, const char *name)
+{
+	for (; *vpp; vpp = &(*vpp)->next) {
+		if (varequal((*vpp)->text, name)) {
+			break;
+		}
+	}
+	return vpp;
+}
diff --git a/examples/error.c b/examples/error.c
new file mode 100644
index 0000000..a0c6cb8
--- /dev/null
+++ b/examples/error.c
@@ -0,0 +1,2 @@
+INIT {
+}
diff --git a/examples/simple.c b/examples/simple.c
index 4d3139c..16629ee 100644
--- a/examples/simple.c
+++ b/examples/simple.c
@@ -1,5 +1,7 @@
+void foo() {
 if (1)
     if (1)
         1;
     else
         1;
+}
diff --git a/examples/small_dash_var.c b/examples/small_dash_var.c
new file mode 100644
index 0000000..33b3c49
--- /dev/null
+++ b/examples/small_dash_var.c
@@ -0,0 +1,678 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 1997-2005
+ *	Herbert Xu <herbert@gondor.apana.org.au>.  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.
+ */
+
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#ifdef HAVE_PATHS_H
+#include <paths.h>
+#endif
+
+/*
+ * Shell variables.
+ */
+
+#include "shell.h"
+#include "output.h"
+#include "expand.h"
+#include "nodes.h"	/* for other headers */
+#include "exec.h"
+#include "syntax.h"
+#include "options.h"
+#include "mail.h"
+#include "var.h"
+#include "memalloc.h"
+#include "error.h"
+#include "mystring.h"
+#include "parser.h"
+#include "show.h"
+#ifndef SMALL
+#include "myhistedit.h"
+#endif
+#include "system.h"
+
+
+#define VTABSIZE 39
+
+
+struct localvar_list {
+	struct localvar_list *next;
+	struct localvar *lv;
+};
+
+MKINIT struct localvar_list *localvar_stack;
+
+const char defpathvar[] =
+	"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin";
+char defifsvar[] = "IFS= \t\n";
+MKINIT char defoptindvar[] = "OPTIND=1";
+
+int lineno;
+char linenovar[sizeof("LINENO=")+sizeof(int)*CHAR_BIT/3+1] = "LINENO=";
+
+/* Some macros in var.h depend on the order, add new variables to the end. */
+struct var varinit[] = {
+#if ATTY
+	{ 0,	VSTRFIXED|VTEXTFIXED|VUNSET,	"ATTY\0",	0 },
+#endif
+	{ 0,	VSTRFIXED|VTEXTFIXED,		defifsvar,	0 },
+	{ 0,	VSTRFIXED|VTEXTFIXED|VUNSET,	"MAIL\0",	changemail },
+	{ 0,	VSTRFIXED|VTEXTFIXED|VUNSET,	"MAILPATH\0",	changemail },
+	{ 0,	VSTRFIXED|VTEXTFIXED,		defpathvar,	changepath },
+	{ 0,	VSTRFIXED|VTEXTFIXED,		"PS1=$ ",	0 },
+	{ 0,	VSTRFIXED|VTEXTFIXED,		"PS2=> ",	0 },
+	{ 0,	VSTRFIXED|VTEXTFIXED,		"PS4=+ ",	0 },
+	{ 0,	VSTRFIXED|VTEXTFIXED,		defoptindvar,	getoptsreset },
+#ifdef WITH_LINENO
+	{ 0,	VSTRFIXED|VTEXTFIXED,		linenovar,	0 },
+#endif
+#ifndef SMALL
+	{ 0,	VSTRFIXED|VTEXTFIXED|VUNSET,	"TERM\0",	0 },
+	{ 0,	VSTRFIXED|VTEXTFIXED|VUNSET,	"HISTSIZE\0",	sethistsize },
+#endif
+};
+
+STATIC struct var *vartab[VTABSIZE];
+
+STATIC struct var **hashvar(const char *);
+STATIC int vpcmp(const void *, const void *);
+STATIC struct var **findvar(struct var **, const char *);
+
+/*
+ * Initialize the varable symbol tables and import the environment
+ */
+
+#ifdef mkinit
+INCLUDE <unistd.h>
+INCLUDE <sys/types.h>
+INCLUDE <sys/stat.h>
+INCLUDE "cd.h"
+INCLUDE "output.h"
+INCLUDE "var.h"
+MKINIT char **environ;
+INIT {
+	char **envp;
+	static char ppid[32] = "PPID=";
+	const char *p;
+	struct stat64 st1, st2;
+
+	initvar();
+	for (envp = environ ; *envp ; envp++) {
+		p = endofname(*envp);
+		if (p != *envp && *p == '=') {
+			setvareq(*envp, VEXPORT|VTEXTFIXED);
+		}
+	}
+
+	setvareq(defifsvar, VTEXTFIXED);
+	setvareq(defoptindvar, VTEXTFIXED);
+
+	fmtstr(ppid + 5, sizeof(ppid) - 5, "%ld", (long) getppid());
+	setvareq(ppid, VTEXTFIXED);
+
+	p = lookupvar("PWD");
+	if (p)
+		if (*p != '/' || stat64(p, &st1) || stat64(".", &st2) ||
+		    st1.st_dev != st2.st_dev || st1.st_ino != st2.st_ino)
+			p = 0;
+	setpwd(p, 0);
+}
+
+RESET {
+	unwindlocalvars(0);
+}
+#endif
+
+static char *varnull(const char *s)
+{
+	return (strchr(s, '=') ?: nullstr - 1) + 1;
+}
+
+/*
+ * This routine initializes the builtin variables.  It is called when the
+ * shell is initialized.
+ */
+
+void
+initvar(void)
+{
+	struct var *vp;
+	struct var *end;
+	struct var **vpp;
+
+	vp = varinit;
+	end = vp + sizeof(varinit) / sizeof(varinit[0]);
+	do {
+		vpp = hashvar(vp->text);
+		vp->next = *vpp;
+		*vpp = vp;
+	} while (++vp < end);
+	/*
+	 * PS1 depends on uid
+	 */
+	if (!geteuid())
+		vps1.text = "PS1=# ";
+}
+
+/*
+ * Set the value of a variable.  The flags argument is ored with the
+ * flags of the variable.  If val is NULL, the variable is unset.
+ */
+
+struct var *setvar(const char *name, const char *val, int flags)
+{
+ 	char *p, *q;
+ 	size_t namelen;
+ 	char *nameeq;
+ 	size_t vallen;
+ 	struct var *vp;
+ 
+ 	q = endofname(name);
+ 	p = strchrnul(q, '=');
+ 	namelen = p - name;
+ 	if (!namelen || p != q)
+ 		sh_error("%.*s: bad variable name", namelen, name);
+ 	vallen = 0;
+ 	if (val == NULL) {
+ 		flags |= VUNSET;
+ 	} else {
+ 		vallen = strlen(val);
+ 	}
+ 	INTOFF;
+ 	p = mempcpy(nameeq = ckmalloc(namelen + vallen + 2), name, namelen);
+ 	if (val) {
+ 		*p++ = '=';
+ 		p = mempcpy(p, val, vallen);
+ 	}
+ 	*p = '\0';
+ 	vp = setvareq(nameeq, flags | VNOSAVE);
+ 	INTON;
+ 
+ 	return vp;
+}
+
+/*
+ * Set the given integer as the value of a variable.  The flags argument is
+ * ored with the flags of the variable.
+ */
+
+intmax_t setvarint(const char *name, intmax_t val, int flags)
+{
+	int len = max_int_length(sizeof(val));
+	char buf[len];
+
+	fmtstr(buf, len, "%" PRIdMAX, val);
+	setvar(name, buf, flags);
+	return val;
+}
+
+
+
+/*
+ * Same as setvar except that the variable and value are passed in
+ * the first argument as name=value.  Since the first argument will
+ * be actually stored in the table, it should not be a string that
+ * will go away.
+ * Called with interrupts off.
+ */
+
+struct var *setvareq(char *s, int flags)
+{
+	struct var *vp, **vpp;
+
+	vpp = hashvar(s);
+	flags |= (VEXPORT & (((unsigned) (1 - aflag)) - 1));
+	vpp = findvar(vpp, s);
+	vp = *vpp;
+	if (vp) {
+		if (vp->flags & VREADONLY) {
+			const char *n;
+
+			if (flags & VNOSAVE)
+				free(s);
+			n = vp->text;
+			sh_error("%.*s: is read only", strchrnul(n, '=') - n,
+				 n);
+		}
+
+		if (flags & VNOSET)
+			goto out;
+
+		if (vp->func && (flags & VNOFUNC) == 0)
+			(*vp->func)(varnull(s));
+
+		if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
+			ckfree(vp->text);
+
+		if (((flags & (VEXPORT|VREADONLY|VSTRFIXED|VUNSET)) |
+		     (vp->flags & VSTRFIXED)) == VUNSET) {
+			*vpp = vp->next;
+			ckfree(vp);
+out_free:
+			if ((flags & (VTEXTFIXED|VSTACK|VNOSAVE)) == VNOSAVE)
+				ckfree(s);
+			goto out;
+		}
+
+		flags |= vp->flags & ~(VTEXTFIXED|VSTACK|VNOSAVE|VUNSET);
+	} else {
+		if (flags & VNOSET)
+			goto out;
+		if ((flags & (VEXPORT|VREADONLY|VSTRFIXED|VUNSET)) == VUNSET)
+			goto out_free;
+		/* not found */
+		vp = ckmalloc(sizeof (*vp));
+		vp->next = *vpp;
+		vp->func = NULL;
+		*vpp = vp;
+	}
+	if (!(flags & (VTEXTFIXED|VSTACK|VNOSAVE)))
+		s = savestr(s);
+	vp->text = s;
+	vp->flags = flags;
+
+out:
+	return vp;
+}
+
+/*
+ * Find the value of a variable.  Returns NULL if not set.
+ */
+
+char *
+lookupvar(const char *name)
+{
+	struct var *v;
+
+	if ((v = *findvar(hashvar(name), name)) && !(v->flags & VUNSET)) {
+#ifdef WITH_LINENO
+		if (v == &vlineno && v->text == linenovar) {
+			fmtstr(linenovar+7, sizeof(linenovar)-7, "%d", lineno);
+		}
+#endif
+		return strchrnul(v->text, '=') + 1;
+	}
+	return NULL;
+}
+
+intmax_t lookupvarint(const char *name)
+{
+	return atomax(lookupvar(name) ?: nullstr, 0);
+}
+
+
+
+/*
+ * Generate a list of variables satisfying the given conditions.
+ */
+
+char **
+listvars(int on, int off, char ***end)
+{
+	struct var **vpp;
+	struct var *vp;
+	char **ep;
+	int mask;
+
+	STARTSTACKSTR(ep);
+	vpp = vartab;
+	mask = on | off;
+	do {
+		for (vp = *vpp ; vp ; vp = vp->next)
+			if ((vp->flags & mask) == on) {
+				if (ep == stackstrend())
+					ep = growstackstr();
+				*ep++ = (char *) vp->text;
+			}
+	} while (++vpp < vartab + VTABSIZE);
+	if (ep == stackstrend())
+		ep = growstackstr();
+	if (end)
+		*end = ep;
+	*ep++ = NULL;
+	return grabstackstr(ep);
+}
+
+
+
+/*
+ * POSIX requires that 'set' (but not export or readonly) output the
+ * variables in lexicographic order - by the locale's collating order (sigh).
+ * Maybe we could keep them in an ordered balanced binary tree
+ * instead of hashed lists.
+ * For now just roll 'em through qsort for printing...
+ */
+
+int
+showvars(const char *prefix, int on, int off)
+{
+	const char *sep;
+	char **ep, **epend;
+
+	ep = listvars(on, off, &epend);
+	qsort(ep, epend - ep, sizeof(char *), vpcmp);
+
+	sep = *prefix ? spcstr : prefix;
+
+	for (; ep < epend; ep++) {
+		const char *p;
+		const char *q;
+
+		p = strchrnul(*ep, '=');
+		q = nullstr;
+		if (*p)
+			q = single_quote(++p);
+
+		out1fmt("%s%s%.*s%s\n", prefix, sep, (int)(p - *ep), *ep, q);
+	}
+
+	return 0;
+}
+
+
+
+/*
+ * The export and readonly commands.
+ */
+
+int
+exportcmd(int argc, char **argv)
+{
+	struct var *vp;
+	char *name;
+	const char *p;
+	char **aptr;
+	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
+	int notp;
+
+	notp = nextopt("p") - 'p';
+	if (notp && ((name = *(aptr = argptr)))) {
+		do {
+			if ((p = strchr(name, '=')) != NULL) {
+				p++;
+			} else {
+				if ((vp = *findvar(hashvar(name), name))) {
+					vp->flags |= flag;
+					continue;
+				}
+			}
+			setvar(name, p, flag);
+		} while ((name = *++aptr) != NULL);
+	} else {
+		showvars(argv[0], flag, 0);
+	}
+	return 0;
+}
+
+
+/*
+ * The "local" command.
+ */
+
+int
+localcmd(int argc, char **argv)
+{
+	char *name;
+
+	if (!localvar_stack)
+		sh_error("not in a function");
+
+	argv = argptr;
+	while ((name = *argv++) != NULL) {
+		mklocal(name, 0);
+	}
+	return 0;
+}
+
+
+/*
+ * Make a variable a local variable.  When a variable is made local, it's
+ * value and flags are saved in a localvar structure.  The saved values
+ * will be restored when the shell function returns.  We handle the name
+ * "-" as a special case.
+ */
+
+void mklocal(char *name, int flags)
+{
+	struct localvar *lvp;
+	struct var **vpp;
+	struct var *vp;
+
+	INTOFF;
+	lvp = ckmalloc(sizeof (struct localvar));
+	if (name[0] == '-' && name[1] == '\0') {
+		char *p;
+		p = ckmalloc(sizeof(optlist));
+		lvp->text = memcpy(p, optlist, sizeof(optlist));
+		vp = NULL;
+	} else {
+		char *eq;
+
+		vpp = hashvar(name);
+		vp = *findvar(vpp, name);
+		eq = strchr(name, '=');
+		if (vp == NULL) {
+			if (eq)
+				vp = setvareq(name, VSTRFIXED | flags);
+			else
+				vp = setvar(name, NULL, VSTRFIXED | flags);
+			lvp->flags = VUNSET;
+		} else {
+			lvp->text = vp->text;
+			lvp->flags = vp->flags;
+			vp->flags |= VSTRFIXED|VTEXTFIXED;
+			if (eq)
+				setvareq(name, flags);
+		}
+	}
+	lvp->vp = vp;
+	lvp->next = localvar_stack->lv;
+	localvar_stack->lv = lvp;
+	INTON;
+}
+
+
+/*
+ * Called after a function returns.
+ * Interrupts must be off.
+ */
+
+static void
+poplocalvars(void)
+{
+	struct localvar_list *ll;
+	struct localvar *lvp, *next;
+	struct var *vp;
+
+	INTOFF;
+	ll = localvar_stack;
+	localvar_stack = ll->next;
+
+	next = ll->lv;
+	ckfree(ll);
+
+	while ((lvp = next) != NULL) {
+		next = lvp->next;
+		vp = lvp->vp;
+		TRACE(("poplocalvar %s\n", vp ? vp->text : "-"));
+		if (vp == NULL) {	/* $- saved */
+			memcpy(optlist, lvp->text, sizeof(optlist));
+			ckfree(lvp->text);
+			optschanged();
+		} else if (lvp->flags == VUNSET) {
+			vp->flags &= ~(VSTRFIXED|VREADONLY);
+			unsetvar(vp->text);
+		} else {
+			if (vp->func)
+				(*vp->func)(varnull(lvp->text));
+			if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
+				ckfree(vp->text);
+			vp->flags = lvp->flags;
+			vp->text = lvp->text;
+		}
+		ckfree(lvp);
+	}
+	INTON;
+}
+
+
+/*
+ * Create a new localvar environment.
+ */
+struct localvar_list *pushlocalvars(int push)
+{
+	struct localvar_list *ll;
+	struct localvar_list *top;
+
+	top = localvar_stack;
+	if (!push)
+		goto out;
+
+	INTOFF;
+	ll = ckmalloc(sizeof(*ll));
+	ll->lv = NULL;
+	ll->next = top;
+	localvar_stack = ll;
+	INTON;
+
+out:
+	return top;
+}
+
+
+void unwindlocalvars(struct localvar_list *stop)
+{
+	while (localvar_stack != stop)
+		poplocalvars();
+}
+
+
+/*
+ * The unset builtin command.  We unset the function before we unset the
+ * variable to allow a function to be unset when there is a readonly variable
+ * with the same name.
+ */
+
+int
+unsetcmd(int argc, char **argv)
+{
+	char **ap;
+	int i;
+	int flag = 0;
+
+	while ((i = nextopt("vf")) != '\0') {
+		flag = i;
+	}
+
+	for (ap = argptr; *ap ; ap++) {
+		if (flag != 'f') {
+			unsetvar(*ap);
+			continue;
+		}
+		if (flag != 'v')
+			unsetfunc(*ap);
+	}
+	return 0;
+}
+
+
+/*
+ * Unset the specified variable.
+ */
+
+void unsetvar(const char *s)
+{
+	setvar(s, 0, 0);
+}
+
+
+
+/*
+ * Find the appropriate entry in the hash table from the name.
+ */
+
+STATIC struct var **
+hashvar(const char *p)
+{
+	unsigned int hashval;
+
+	hashval = ((unsigned char) *p) << 4;
+	while (*p && *p != '=')
+		hashval += (unsigned char) *p++;
+	return &vartab[hashval % VTABSIZE];
+}
+
+
+
+/*
+ * Compares two strings up to the first = or '\0'.  The first
+ * string must be terminated by '='; the second may be terminated by
+ * either '=' or '\0'.
+ */
+
+int
+varcmp(const char *p, const char *q)
+{
+	int c, d;
+
+	while ((c = *p) == (d = *q)) {
+		if (!c || c == '=')
+			goto out;
+		p++;
+		q++;
+	}
+	if (c == '=')
+		c = 0;
+	if (d == '=')
+		d = 0;
+out:
+	return c - d;
+}
+
+STATIC int
+vpcmp(const void *a, const void *b)
+{
+	return varcmp(*(const char **)a, *(const char **)b);
+}
+
+STATIC struct var **
+findvar(struct var **vpp, const char *name)
+{
+	for (; *vpp; vpp = &(*vpp)->next) {
+		if (varequal((*vpp)->text, name)) {
+			break;
+		}
+	}
+	return vpp;
+}
diff --git a/examples/tiny.c b/examples/tiny.c
new file mode 100644
index 0000000..ff80f0c
--- /dev/null
+++ b/examples/tiny.c
@@ -0,0 +1,430 @@
+int
+save_bash_input (fd, new_fd)
+     int fd, new_fd;
+{
+  int nfd;
+
+  /* Sync the stream so we can re-read from the new file descriptor.  We
+     might be able to avoid this by copying the buffered stream verbatim
+     to the new file descriptor. */
+  if (buffers[fd])
+    sync_buffered_stream (fd);
+
+  /* Now take care of duplicating the file descriptor that bash is
+     using for input, so we can reinitialize it later. */
+  nfd = (new_fd == -1) ? fcntl (fd, F_DUPFD, 10) : new_fd;
+  if (nfd == -1)
+    {
+      if (fcntl (fd, F_GETFD, 0) == 0)
+	sys_error (_("cannot allocate new file descriptor for bash input from fd %d"), fd);
+      return -1;
+    }
+
+  if (nfd < nbuffers && buffers[nfd])
+    {
+      /* What's this?  A stray buffer without an associated open file
+	 descriptor?  Free up the buffer and report the error. */
+      internal_error (_("save_bash_input: buffer already exists for new fd %d"), nfd);
+      if (buffers[nfd]->b_flag & B_SHAREDBUF)
+	buffers[nfd]->b_buffer = (char *)NULL;
+      free_buffered_stream (buffers[nfd]);
+    }
+
+  /* Reinitialize bash_input.location. */
+  if (bash_input.type == st_bstream)
+    {
+      bash_input.location.buffered_fd = nfd;
+      fd_to_buffered_stream (nfd);
+      close_buffered_fd (fd);	/* XXX */
+    }
+  else
+    /* If the current input type is not a buffered stream, but the shell
+       is not interactive and therefore using a buffered stream to read
+       input (e.g. with an `eval exec 3>output' inside a script), note
+       that the input fd has been changed.  pop_stream() looks at this
+       value and adjusts the input fd to the new value of
+       default_buffered_input accordingly. */
+    bash_input_fd_changed++;
+
+  if (default_buffered_input == fd)
+    default_buffered_input = nfd;
+
+  SET_CLOSE_ON_EXEC (nfd);
+  return nfd;
+}
+
+/* Check that file descriptor FD is not the one that bash is currently
+   using to read input from a script.  FD is about to be duplicated onto,
+   which means that the kernel will close it for us.  If FD is the bash
+   input file descriptor, we need to seek backwards in the script (if
+   possible and necessary -- scripts read from stdin are still unbuffered),
+   allocate a new file descriptor to use for bash input, and re-initialize
+   the buffered stream.  Make sure the file descriptor used to save bash
+   input is set close-on-exec. Returns 0 on success, -1 on failure.  This
+   works only if fd is > 0 -- if fd == 0 and bash is reading input from
+   fd 0, sync_buffered_stream is used instead, to cooperate with input
+   redirection (look at redir.c:add_undo_redirect()). */
+int
+check_bash_input (fd)
+     int fd;
+{
+  if (fd_is_bash_input (fd))
+    {
+      if (fd > 0)
+	return ((save_bash_input (fd, -1) == -1) ? -1 : 0);
+      else if (fd == 0)
+        return ((sync_buffered_stream (fd) == -1) ? -1 : 0);
+    }
+  return 0;
+}
+      
+/* This is the buffered stream analogue of dup2(fd1, fd2).  The
+   BUFFERED_STREAM corresponding to fd2 is deallocated, if one exists.
+   BUFFERS[fd1] is copied to BUFFERS[fd2].  This is called by the
+   redirect code for constructs like 4<&0 and 3</etc/rc.local. */
+int
+duplicate_buffered_stream (fd1, fd2)
+     int fd1, fd2;
+{
+  int is_bash_input, m;
+
+  if (fd1 == fd2)
+    return 0;
+
+  m = max (fd1, fd2);
+  ALLOCATE_BUFFERS (m);
+
+  /* If FD2 is the file descriptor bash is currently using for shell input,
+     we need to do some extra work to make sure that the buffered stream
+     actually exists (it might not if fd1 was not active, and the copy
+     didn't actually do anything). */
+  is_bash_input = (bash_input.type == st_bstream) &&
+		  (bash_input.location.buffered_fd == fd2);
+
+  if (buffers[fd2])
+    {
+      /* If the two objects share the same b_buffer, don't free it. */
+      if (buffers[fd1] && buffers[fd1]->b_buffer && buffers[fd1]->b_buffer == buffers[fd2]->b_buffer)
+	buffers[fd2] = (BUFFERED_STREAM *)NULL;
+      /* If this buffer is shared with another fd, don't free the buffer */
+      else if (buffers[fd2]->b_flag & B_SHAREDBUF)
+	{
+	  buffers[fd2]->b_buffer = (char *)NULL;
+	  free_buffered_stream (buffers[fd2]);
+	}
+      else
+	free_buffered_stream (buffers[fd2]);
+    }
+  buffers[fd2] = copy_buffered_stream (buffers[fd1]);
+  if (buffers[fd2])
+    buffers[fd2]->b_fd = fd2;
+
+  if (is_bash_input)
+    {
+      if (!buffers[fd2])
+	fd_to_buffered_stream (fd2);
+      buffers[fd2]->b_flag |= B_WASBASHINPUT;
+    }
+
+  if (fd_is_bash_input (fd1) || (buffers[fd1] && (buffers[fd1]->b_flag & B_SHAREDBUF)))
+    buffers[fd2]->b_flag |= B_SHAREDBUF;
+
+  return (fd2);
+}
+
+/* Return 1 if a seek on FD will succeed. */
+#define fd_is_seekable(fd) (lseek ((fd), 0L, SEEK_CUR) >= 0)
+
+/* Take FD, a file descriptor, and create and return a buffered stream
+   corresponding to it.  If something is wrong and the file descriptor
+   is invalid, return a NULL stream. */
+BUFFERED_STREAM *
+fd_to_buffered_stream (fd)
+     int fd;
+{
+  char *buffer;
+  size_t size;
+  struct stat sb;
+
+  if (fstat (fd, &sb) < 0)
+    {
+      close (fd);
+      return ((BUFFERED_STREAM *)NULL);
+    }
+
+  size = (fd_is_seekable (fd)) ? min (sb.st_size, MAX_INPUT_BUFFER_SIZE) : 1;
+  if (size == 0)
+    size = 1;
+  buffer = (char *)xmalloc (size);
+
+  return (make_buffered_stream (fd, buffer, size));
+}
+
+/* Return a buffered stream corresponding to FILE, a file name. */
+BUFFERED_STREAM *
+open_buffered_stream (file)
+     char *file;
+{
+  int fd;
+
+  fd = open (file, O_RDONLY);
+  return ((fd >= 0) ? fd_to_buffered_stream (fd) : (BUFFERED_STREAM *)NULL);
+}
+
+/* Deallocate a buffered stream and free up its resources.  Make sure we
+   zero out the slot in BUFFERS that points to BP. */
+void
+free_buffered_stream (bp)
+     BUFFERED_STREAM *bp;
+{
+  int n;
+
+  if (!bp)
+    return;
+
+  n = bp->b_fd;
+  if (bp->b_buffer)
+    free (bp->b_buffer);
+  free (bp);
+  buffers[n] = (BUFFERED_STREAM *)NULL;
+}
+
+/* Close the file descriptor associated with BP, a buffered stream, and free
+   up the stream.  Return the status of closing BP's file descriptor. */
+int
+close_buffered_stream (bp)
+     BUFFERED_STREAM *bp;
+{
+  int fd;
+
+  if (!bp)
+    return (0);
+  fd = bp->b_fd;
+  if (bp->b_flag & B_SHAREDBUF)
+    bp->b_buffer = (char *)NULL;
+  free_buffered_stream (bp);
+  return (close (fd));
+}
+
+/* Deallocate the buffered stream associated with file descriptor FD, and
+   close FD.  Return the status of the close on FD. */
+int
+close_buffered_fd (fd)
+     int fd;
+{
+  if (fd < 0)
+    {
+      errno = EBADF;
+      return -1;
+    }
+  if (fd >= nbuffers || !buffers || !buffers[fd])
+    return (close (fd));
+  return (close_buffered_stream (buffers[fd]));
+}
+
+/* Make the BUFFERED_STREAM associated with buffers[FD] be BP, and return
+   the old BUFFERED_STREAM. */
+BUFFERED_STREAM *
+set_buffered_stream (fd, bp)
+     int fd;
+     BUFFERED_STREAM *bp;
+{
+  BUFFERED_STREAM *ret;
+
+  ret = buffers[fd];
+  buffers[fd] = bp;
+  return ret;
+}
+
+/* Read a buffer full of characters from BP, a buffered stream. */
+static int
+b_fill_buffer (bp)
+     BUFFERED_STREAM *bp;
+{
+  ssize_t nr;
+  off_t o;
+
+  CHECK_TERMSIG;
+  /* In an environment where text and binary files are treated differently,
+     compensate for lseek() on text files returning an offset different from
+     the count of characters read() returns.  Text-mode streams have to be
+     treated as unbuffered. */
+  if ((bp->b_flag & (B_TEXT | B_UNBUFF)) == B_TEXT)
+    {
+      o = lseek (bp->b_fd, 0, SEEK_CUR);
+      nr = zread (bp->b_fd, bp->b_buffer, bp->b_size);
+      if (nr > 0 && nr < lseek (bp->b_fd, 0, SEEK_CUR) - o)
+	{
+	  lseek (bp->b_fd, o, SEEK_SET);
+	  bp->b_flag |= B_UNBUFF;
+	  bp->b_size = 1;
+	  nr = zread (bp->b_fd, bp->b_buffer, bp->b_size);
+	}
+    }
+  else
+    nr = zread (bp->b_fd, bp->b_buffer, bp->b_size);
+  if (nr <= 0)
+    {
+      bp->b_used = bp->b_inputp = 0;
+      bp->b_buffer[0] = 0;
+      if (nr == 0)
+	bp->b_flag |= B_EOF;
+      else
+	bp->b_flag |= B_ERROR;
+      return (EOF);
+    }
+
+  bp->b_used = nr;
+  bp->b_inputp = 0;
+  return (bp->b_buffer[bp->b_inputp++] & 0xFF);
+}
+
+/* Get a character from buffered stream BP. */
+#define bufstream_getc(bp) \
+  (bp->b_inputp == bp->b_used || !bp->b_used) \
+  		? b_fill_buffer (bp) \
+		: bp->b_buffer[bp->b_inputp++] & 0xFF
+
+/* Push C back onto buffered stream BP. */
+static int
+bufstream_ungetc(c, bp)
+     int c;
+     BUFFERED_STREAM *bp;
+{
+  if (c == EOF || bp == 0 || bp->b_inputp == 0)
+    return (EOF);
+
+  bp->b_buffer[--bp->b_inputp] = c;
+  return (c);
+}
+
+/* Seek backwards on file BFD to synchronize what we've read so far
+   with the underlying file pointer. */
+int
+sync_buffered_stream (bfd)
+     int bfd;
+{
+  BUFFERED_STREAM *bp;
+  off_t chars_left;
+
+  if (buffers == 0 || (bp = buffers[bfd]) == 0)
+    return (-1);
+
+  chars_left = bp->b_used - bp->b_inputp;
+  if (chars_left)
+    lseek (bp->b_fd, -chars_left, SEEK_CUR);
+  bp->b_used = bp->b_inputp = 0;
+  return (0);
+}
+
+int
+buffered_getchar ()
+{
+  CHECK_TERMSIG;
+
+  if (bash_input.location.buffered_fd < 0 || buffers[bash_input.location.buffered_fd] == 0)
+    return EOF;
+
+#if !defined (DJGPP)
+  return (bufstream_getc (buffers[bash_input.location.buffered_fd]));
+#else
+  /* On DJGPP, ignore \r. */
+  int ch;
+  while ((ch = bufstream_getc (buffers[bash_input.location.buffered_fd])) == '\r')
+    ;
+  return ch;
+#endif
+}
+
+int
+buffered_ungetchar (c)
+     int c;
+{
+  return (bufstream_ungetc (c, buffers[bash_input.location.buffered_fd]));
+}
+
+/* Make input come from file descriptor BFD through a buffered stream. */
+void
+with_input_from_buffered_stream (bfd, name)
+     int bfd;
+     char *name;
+{
+  INPUT_STREAM location;
+  BUFFERED_STREAM *bp;
+
+  location.buffered_fd = bfd;
+  /* Make sure the buffered stream exists. */
+  bp = fd_to_buffered_stream (bfd);
+  init_yy_io (bp == 0 ? return_EOF : buffered_getchar,
+	      buffered_ungetchar, st_bstream, name, location);
+}
+
+#if defined (TEST)
+void *
+xmalloc(s)
+int s;
+{
+	return (malloc (s));
+}
+
+void *
+xrealloc(s, size)
+char	*s;
+int	size;
+{
+	if (!s)
+		return(malloc (size));
+	else
+		return(realloc (s, size));
+}
+
+void
+init_yy_io ()
+{
+}
+
+process(bp)
+BUFFERED_STREAM *bp;
+{
+	int c;
+
+	while ((c = bufstream_getc(bp)) != EOF)
+		putchar(c);
+}
+
+BASH_INPUT bash_input;
+
+struct stat dsb;		/* can be used from gdb */
+
+/* imitate /bin/cat */
+main(argc, argv)
+int	argc;
+char	**argv;
+{
+	register int i;
+	BUFFERED_STREAM *bp;
+
+	if (argc == 1) {
+		bp = fd_to_buffered_stream (0);
+		process(bp);
+		exit(0);
+	}
+	for (i = 1; i < argc; i++) {
+		if (argv[i][0] == '-' && argv[i][1] == '\0') {
+			bp = fd_to_buffered_stream (0);
+			if (!bp)
+				continue;
+			process(bp);
+			free_buffered_stream (bp);
+		} else {
+			bp = open_buffered_stream (argv[i]);
+			if (!bp)
+				continue;
+			process(bp);
+			close_buffered_stream (bp);
+		}
+	}
+	exit(0);
+}
+#endif /* TEST */
+#endif /* BUFFERED_INPUT */