diff --git a/libc/bionic/locale.cpp b/libc/bionic/locale.cpp
new file mode 100644
index 0000000..4fade84
--- /dev/null
+++ b/libc/bionic/locale.cpp
@@ -0,0 +1,156 @@
+/*
+ * 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 <locale.h>
+#include <pthread.h>
+#include <stdlib.h>
+
+// We currently support a single locale, the "C" locale (also known as "POSIX").
+
+struct __locale_t {
+  // Because we only support one locale, these are just tokens with no data.
+};
+
+static pthread_once_t gLocaleOnce = PTHREAD_ONCE_INIT;
+static lconv gLocale;
+
+static pthread_once_t gUselocaleKeyOnce = PTHREAD_ONCE_INIT;
+static pthread_key_t gUselocaleKey;
+
+static void __locale_init() {
+  gLocale.decimal_point = const_cast<char*>(".");
+
+  char* not_available = const_cast<char*>("");
+  gLocale.thousands_sep = not_available;
+  gLocale.grouping = not_available;
+  gLocale.int_curr_symbol = not_available;
+  gLocale.currency_symbol = not_available;
+  gLocale.mon_decimal_point = not_available;
+  gLocale.mon_thousands_sep = not_available;
+  gLocale.mon_grouping = not_available;
+  gLocale.positive_sign = not_available;
+  gLocale.negative_sign = not_available;
+
+  gLocale.int_frac_digits = CHAR_MAX;
+  gLocale.frac_digits = CHAR_MAX;
+  gLocale.p_cs_precedes = CHAR_MAX;
+  gLocale.p_sep_by_space = CHAR_MAX;
+  gLocale.n_cs_precedes = CHAR_MAX;
+  gLocale.n_sep_by_space = CHAR_MAX;
+  gLocale.p_sign_posn = CHAR_MAX;
+  gLocale.n_sign_posn = CHAR_MAX;
+  gLocale.int_p_cs_precedes = CHAR_MAX;
+  gLocale.int_p_sep_by_space = CHAR_MAX;
+  gLocale.int_n_cs_precedes = CHAR_MAX;
+  gLocale.int_n_sep_by_space = CHAR_MAX;
+  gLocale.int_p_sign_posn = CHAR_MAX;
+  gLocale.int_n_sign_posn = CHAR_MAX;
+}
+
+static void __uselocale_key_init() {
+  pthread_key_create(&gUselocaleKey, NULL);
+}
+
+static bool __is_supported_locale(const char* locale) {
+  return (strcmp(locale, "") == 0 || strcmp(locale, "C") == 0 || strcmp(locale, "POSIX") == 0);
+}
+
+static locale_t __new_locale() {
+  return reinterpret_cast<locale_t>(malloc(sizeof(__locale_t)));
+}
+
+lconv* localeconv() {
+  pthread_once(&gLocaleOnce, __locale_init);
+  return &gLocale;
+}
+
+locale_t duplocale(locale_t l) {
+  locale_t clone = __new_locale();
+  if (clone != NULL && l != LC_GLOBAL_LOCALE) {
+    *clone = *l;
+  }
+  return clone;
+}
+
+void freelocale(locale_t l) {
+  free(l);
+}
+
+locale_t newlocale(int category_mask, const char* locale_name, locale_t /*base*/) {
+  // Is 'category_mask' valid?
+  if ((category_mask & ~LC_ALL_MASK) != 0) {
+    errno = EINVAL;
+    return NULL;
+  }
+
+  if (!__is_supported_locale(locale_name)) {
+    errno = ENOENT;
+    return NULL;
+  }
+
+  return __new_locale();
+}
+
+char* setlocale(int category, char const* locale_name) {
+  // Is 'category' valid?
+  if (category < LC_CTYPE || category > LC_IDENTIFICATION) {
+    errno = EINVAL;
+    return NULL;
+  }
+
+  // Caller just wants to query the current locale?
+  if (locale_name == NULL) {
+    return const_cast<char*>("C");
+  }
+
+  // Caller wants one of the mandatory POSIX locales?
+  if (__is_supported_locale(locale_name)) {
+    return const_cast<char*>("C");
+  }
+
+  // We don't support any other locales.
+  errno = ENOENT;
+  return NULL;
+}
+
+locale_t uselocale(locale_t new_locale) {
+  pthread_once(&gUselocaleKeyOnce, __uselocale_key_init);
+
+  locale_t old_locale = static_cast<locale_t>(pthread_getspecific(gUselocaleKey));
+
+  // If this is the first call to uselocale(3) on this thread, we return LC_GLOBAL_LOCALE.
+  if (old_locale == NULL) {
+    old_locale = LC_GLOBAL_LOCALE;
+  }
+
+  if (new_locale != NULL) {
+    pthread_setspecific(gUselocaleKey, new_locale);
+  }
+
+  return old_locale;
+}
diff --git a/libc/include/xlocale.h b/libc/include/xlocale.h
new file mode 100644
index 0000000..f7eb8f4
--- /dev/null
+++ b/libc/include/xlocale.h
@@ -0,0 +1,36 @@
+/*
+ * 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 _XLOCALE_H_
+#define _XLOCALE_H_
+
+/* If we just use void* here, GCC exposes that in error messages. */
+struct __locale_t;
+typedef struct __locale_t* locale_t;
+
+#endif /* _XLOCALE_H_ */