diff --git a/libc/Android.mk b/libc/Android.mk
index d6c0599..5befacf 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -140,6 +140,7 @@
     bionic/mkdir.cpp \
     bionic/mkfifo.cpp \
     bionic/mknod.cpp \
+    bionic/mntent.cpp \
     bionic/open.cpp \
     bionic/pause.cpp \
     bionic/pipe.cpp \
diff --git a/libc/bionic/mntent.cpp b/libc/bionic/mntent.cpp
new file mode 100644
index 0000000..93b6915
--- /dev/null
+++ b/libc/bionic/mntent.cpp
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2008 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 <mntent.h>
+
+mntent* getmntent(FILE*) {
+  return NULL;
+}
+
+mntent* getmntent_r(FILE*, struct mntent*, char*, int) {
+  return NULL;
+}
+
+FILE* setmntent(const char* path, const char* mode) {
+  return fopen(path, mode);
+}
+
+int endmntent(FILE* fp) {
+  if (fp != NULL) {
+    fclose(fp);
+  }
+  return 1;
+}
diff --git a/libc/bionic/stubs.cpp b/libc/bionic/stubs.cpp
index 41ecd09..9b025df 100644
--- a/libc/bionic/stubs.cpp
+++ b/libc/bionic/stubs.cpp
@@ -444,21 +444,6 @@
   UNIMPLEMENTED;
 }
 
-mntent* getmntent(FILE* /*f*/) {
-  UNIMPLEMENTED;
-  return NULL;
-}
-
-FILE* setmntent(const char*, const char*) {
-  UNIMPLEMENTED;
-  return NULL;
-}
-
-int endmntent(FILE*) {
-  UNIMPLEMENTED;
-  return 1; /* Allways returns 1 according to man */
-}
-
 char* ttyname(int /*fd*/) { // NOLINT: implementing bad function.
   UNIMPLEMENTED;
   return NULL;
diff --git a/libc/include/mntent.h b/libc/include/mntent.h
index 6cc0b18..de285d0 100644
--- a/libc/include/mntent.h
+++ b/libc/include/mntent.h
@@ -35,23 +35,21 @@
 #define MOUNTED _PATH_MOUNTED
 #define MNTTYPE_IGNORE "ignore"
 
-struct mntent
-{
-    char* mnt_fsname;
-    char* mnt_dir;
-    char* mnt_type;
-    char* mnt_opts;
-    int mnt_freq;
-    int mnt_passno;
+struct mntent {
+  char* mnt_fsname;
+  char* mnt_dir;
+  char* mnt_type;
+  char* mnt_opts;
+  int mnt_freq;
+  int mnt_passno;
 };
 
-
 __BEGIN_DECLS
 
-
-struct mntent* getmntent(FILE*);
-FILE* setmntent(const char*, const char*);
 int endmntent(FILE*);
+struct mntent* getmntent(FILE*);
+struct mntent* getmntent_r(FILE*, struct mntent*, char*, int);
+FILE* setmntent(const char*, const char*);
 
 __END_DECLS
 
diff --git a/tests/Android.mk b/tests/Android.mk
index 10e288c..b17492a 100644
--- a/tests/Android.mk
+++ b/tests/Android.mk
@@ -59,6 +59,7 @@
     locale_test.cpp \
     malloc_test.cpp \
     math_test.cpp \
+    mntent_test.cpp \
     netdb_test.cpp \
     pthread_test.cpp \
     regex_test.cpp \
diff --git a/tests/mntent_test.cpp b/tests/mntent_test.cpp
new file mode 100644
index 0000000..637cb52
--- /dev/null
+++ b/tests/mntent_test.cpp
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <gtest/gtest.h>
+
+#include <mntent.h>
+
+TEST(mntent, mntent_smoke) {
+  FILE* fp = setmntent("/no/mnt/tab/on/android", "r");
+  ASSERT_TRUE(fp == NULL);
+
+#if __BIONIC__ // glibc doesn't let you call getmntent/getmntent_r with a NULL FILE*.
+  ASSERT_TRUE(getmntent(fp) == NULL);
+
+  struct mntent mbuf;
+  char cbuf[32];
+  ASSERT_TRUE(getmntent_r(fp, &mbuf, cbuf, sizeof(cbuf)) == NULL);
+#endif
+
+  ASSERT_EQ(1, endmntent(fp));
+}