diff --git a/libc/Android.mk b/libc/Android.mk
index 937f741..c268a87 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -62,6 +62,7 @@
     bionic/system_properties_compat.c \
     stdio/snprintf.c\
     stdio/sprintf.c \
+    stdio/stdio_ext.cpp \
 
 # Fortify implementations of libc functions.
 libc_common_src_files += \
diff --git a/libc/include/stdio.h b/libc/include/stdio.h
index 516f8cb..8727a9f 100644
--- a/libc/include/stdio.h
+++ b/libc/include/stdio.h
@@ -343,6 +343,11 @@
 int	 vasprintf(char ** __restrict, const char * __restrict,
     __va_list)
 		__printflike(2, 0);
+
+void clearerr_unlocked(FILE*);
+int feof_unlocked(FILE*);
+int ferror_unlocked(FILE*);
+
 __END_DECLS
 
 /*
diff --git a/libc/include/stdio_ext.h b/libc/include/stdio_ext.h
new file mode 100644
index 0000000..f299e54
--- /dev/null
+++ b/libc/include/stdio_ext.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
+ * COPYRIGHT OWNER 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 _STDIO_EXT_H
+#define _STDIO_EXT_H
+
+#include <sys/cdefs.h>
+#include <stdio.h>
+
+#define FSETLOCKING_QUERY 0
+#define FSETLOCKING_INTERNAL 1
+#define FSETLOCKING_BYCALLER 2
+
+__BEGIN_DECLS
+
+size_t __fbufsize(FILE*);
+int __freading(FILE*);
+int __fwriting(FILE*);
+int __freadable(FILE*);
+int __fwritable(FILE*);
+int __flbf(FILE*);
+void __fpurge(FILE*);
+size_t __fpending(FILE*);
+void _flushlbf(void);
+int __fsetlocking(FILE*, int);
+
+__END_DECLS
+
+#endif /* _STDIO_EXT_H */
diff --git a/libc/stdio/stdio_ext.cpp b/libc/stdio/stdio_ext.cpp
new file mode 100644
index 0000000..bfdecb8
--- /dev/null
+++ b/libc/stdio/stdio_ext.cpp
@@ -0,0 +1,96 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
+ * COPYRIGHT OWNER 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 <stdio_ext.h>
+
+#include <stdio.h>
+#include "local.h"
+
+#define FSETLOCKING_QUERY 0
+#define FSETLOCKING_INTERNAL 1
+#define FSETLOCKING_BYCALLER 2
+
+size_t __fbufsize(FILE* fp) {
+  return fp->_bf._size;
+}
+
+/* For a _SRW stream, we don't know whether we last read or wrote.
+int __freading(FILE* fp) {
+  return (fp->_flags & _SRD) != 0 || ...;
+}
+*/
+
+/* For a _SRW stream, we don't know whether we last read or wrote.
+int __fwriting(FILE*) {
+  return (fp->_flags & _SWR) != 0 || ...;
+}
+*/
+
+int __freadable(FILE* fp) {
+  return (fp->_flags & (__SRD|__SRW)) != 0;
+}
+
+int __fwritable(FILE* fp) {
+  return (fp->_flags & (__SWR|__SRW)) != 0;
+}
+
+int __flbf(FILE* fp) {
+  return (fp->_flags & __SLBF) != 0;
+}
+
+void __fpurge(FILE* fp) {
+  fpurge(fp);
+}
+
+size_t __fpending(FILE* fp) {
+  return fp->_p - fp->_bf._base;
+}
+
+void _flushlbf() {
+  // If we flush all streams, we know we've flushed all the line-buffered streams.
+  fflush(NULL);
+}
+
+int __fsetlocking(FILE*, int) {
+  // We don't currently have an implementation that would obey this,
+  // so make setting the state a no-op and always return "we handle locking for you".
+  // http://b/17154740 suggests ways we could fix this.
+  return FSETLOCKING_INTERNAL;
+}
+
+void clearerr_unlocked(FILE* fp) {
+  return __sclearerr(fp);
+}
+
+int feof_unlocked(FILE* fp) {
+  return __sfeof(fp);
+}
+
+int ferror_unlocked(FILE* fp) {
+  return __sferror(fp);
+}