diff --git a/libc/bionic/system_properties.c b/libc/bionic/system_properties.c
index 0587430..d969507 100644
--- a/libc/bionic/system_properties.c
+++ b/libc/bionic/system_properties.c
@@ -26,6 +26,7 @@
  * SUCH DAMAGE.
  */
 #include <stdio.h>
+#include <stdint.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <stddef.h>
@@ -49,6 +50,25 @@
 
 #include <sys/atomics.h>
 
+struct prop_area {
+    unsigned volatile count;
+    unsigned volatile serial;
+    unsigned magic;
+    unsigned version;
+    unsigned reserved[4];
+    unsigned toc[1];
+};
+
+typedef struct prop_area prop_area;
+
+struct prop_info {
+    char name[PROP_NAME_MAX];
+    unsigned volatile serial;
+    char value[PROP_VALUE_MAX];
+};
+
+typedef struct prop_info prop_info;
+
 static const char property_service_socket[] = "/dev/socket/" PROP_SERVICE_NAME;
 
 static unsigned dummy_props = 0;
@@ -66,6 +86,17 @@
     return atoi(env);
 }
 
+void __system_property_area_init(void *data)
+{
+    prop_area *pa = data;
+    memset(pa, 0, PA_SIZE);
+    pa->magic = PROP_AREA_MAGIC;
+    pa->version = PROP_AREA_VERSION;
+
+    /* plug into the lib property services */
+    __system_property_area__ = pa;
+}
+
 int __system_properties_init(void)
 {
     bool fromFile = true;
@@ -147,6 +178,11 @@
     unsigned len = strlen(name);
     prop_info *pi;
 
+    if (len >= PROP_NAME_MAX)
+        return 0;
+    if (len < 1)
+        return 0;
+
     while(count--) {
         unsigned entry = *toc++;
         if(TOC_NAME_LEN(entry) != len) continue;
@@ -294,3 +330,68 @@
     }
     return 0;
 }
+
+int __system_property_update(prop_info *pi, const char *value, unsigned int len)
+{
+    prop_area *pa = __system_property_area__;
+
+    if (len >= PROP_VALUE_MAX)
+        return -1;
+
+    pi->serial = pi->serial | 1;
+    memcpy(pi->value, value, len + 1);
+    pi->serial = (len << 24) | ((pi->serial + 1) & 0xffffff);
+    __futex_wake(&pi->serial, INT32_MAX);
+
+    pa->serial++;
+    __futex_wake(&pa->serial, INT32_MAX);
+
+    return 0;
+}
+
+int __system_property_add(const char *name, unsigned int namelen,
+            const char *value, unsigned int valuelen)
+{
+    prop_area *pa = __system_property_area__;
+    prop_info *pa_info_array = (void*) (((char*) pa) + PA_INFO_START);
+    prop_info *pi;
+
+    if (pa->count == PA_COUNT_MAX)
+        return -1;
+    if (namelen >= PROP_NAME_MAX)
+        return -1;
+    if (valuelen >= PROP_VALUE_MAX)
+        return -1;
+    if (namelen < 1)
+        return -1;
+
+    pi = pa_info_array + pa->count;
+    pi->serial = (valuelen << 24);
+    memcpy(pi->name, name, namelen + 1);
+    memcpy(pi->value, value, valuelen + 1);
+
+    pa->toc[pa->count] =
+        (namelen << 24) | (((unsigned) pi) - ((unsigned) pa));
+
+    pa->count++;
+    pa->serial++;
+    __futex_wake(&pa->serial, INT32_MAX);
+
+    return 0;
+}
+
+unsigned int __system_property_serial(const prop_info *pi)
+{
+    return pi->serial;
+}
+
+unsigned int __system_property_wait_any(unsigned int serial)
+{
+    prop_area *pa = __system_property_area__;
+
+    do {
+        __futex_wait(&pa->serial, serial, 0);
+    } while(pa->serial == serial);
+
+    return pa->serial;
+}
diff --git a/libc/include/sys/_system_properties.h b/libc/include/sys/_system_properties.h
index 5d2043d..c5bc223 100644
--- a/libc/include/sys/_system_properties.h
+++ b/libc/include/sys/_system_properties.h
@@ -34,7 +34,6 @@
 #else
 #include <sys/system_properties.h>
 
-typedef struct prop_area prop_area;
 typedef struct prop_msg prop_msg;
 
 #define PROP_AREA_MAGIC   0x504f5250
@@ -43,29 +42,20 @@
 #define PROP_SERVICE_NAME "property_service"
 #define PROP_FILENAME "/dev/__properties__"
 
-/* #define PROP_MAX_ENTRIES 247 */
-/* 247 -> 32620 bytes (<32768) */
+/* (8 header words + 247 toc words) = 1020 bytes */
+/* 1024 bytes header and toc + 247 prop_infos @ 128 bytes = 32640 bytes */
+
+#define PA_COUNT_MAX  247
+#define PA_INFO_START 1024
+#define PA_SIZE       32768
 
 #define TOC_NAME_LEN(toc)       ((toc) >> 24)
 #define TOC_TO_INFO(area, toc)  ((prop_info*) (((char*) area) + ((toc) & 0xFFFFFF)))
 
-struct prop_area {
-    unsigned volatile count;
-    unsigned volatile serial;
-    unsigned magic;
-    unsigned version;
-    unsigned reserved[4];
-    unsigned toc[1];
-};
-
 #define SERIAL_VALUE_LEN(serial) ((serial) >> 24)
 #define SERIAL_DIRTY(serial) ((serial) & 1)
 
-struct prop_info {
-    char name[PROP_NAME_MAX];
-    unsigned volatile serial;
-    char value[PROP_VALUE_MAX];
-};
+__BEGIN_DECLS
 
 struct prop_msg 
 {
@@ -106,5 +96,47 @@
 #define PROP_PATH_LOCAL_OVERRIDE   "/data/local.prop"
 #define PROP_PATH_FACTORY          "/factory/factory.prop"
 
+/*
+** Initialize the area to be used to store properties.  Can
+** only be done by a single process that has write access to
+** the property area.
+*/
+void __system_property_area_init(void *data);
+
+/* Add a new system property.  Can only be done by a single
+** process that has write access to the property area, and
+** that process must handle sequencing to ensure the property
+** does not already exist and that only one property is added
+** or updated at a time.
+**
+** Returns 0 on success, -1 if the property area is full.
+*/
+int __system_property_add(const char *name, unsigned int namelen,
+			const char *value, unsigned int valuelen);
+
+/* Update the value of a system property returned by
+** __system_property_find.  Can only be done by a single process
+** that has write access to the property area, and that process
+** must handle sequencing to ensure that only one property is
+** updated at a time.
+**
+** Returns 0 on success, -1 if the parameters are incorrect.
+*/
+int __system_property_update(prop_info *pi, const char *value, unsigned int len);
+
+/* Read the serial number of a system property returned by
+** __system_property_find.
+**
+** Returns the serial number on success, -1 on error.
+*/
+unsigned int __system_property_serial(const prop_info *pi);
+
+/* Wait for any system property to be updated.  Caller must pass
+** in 0 the first time, and the previous return value on each
+** successive call. */
+unsigned int __system_property_wait_any(unsigned int serial);
+
+__END_DECLS
+
 #endif
 #endif
diff --git a/libc/netbsd/resolv/res_state.c b/libc/netbsd/resolv/res_state.c
index 3e1f67b..2b34867 100644
--- a/libc/netbsd/resolv/res_state.c
+++ b/libc/netbsd/resolv/res_state.c
@@ -71,7 +71,7 @@
         rt->_serial = 0;
         rt->_pi = (struct prop_info*) __system_property_find("net.change");
         if (rt->_pi) {
-            rt->_serial = rt->_pi->serial;
+            rt->_serial = __system_property_serial(rt->_pi);
         }
         memset(rt->_rstatic, 0, sizeof rt->_rstatic);
     }
@@ -135,14 +135,14 @@
                 return rt;
             }
         }
-        if (rt->_serial == rt->_pi->serial) {
+        if (rt->_serial == __system_property_serial(rt->_pi)) {
             /* Nothing changed, so return the current state */
             D("%s: tid=%d rt=%p nothing changed, returning",
               __FUNCTION__, gettid(), rt);
             return rt;
         }
         /* Update the recorded serial number, and go reset the state */
-        rt->_serial = rt->_pi->serial;
+        rt->_serial = __system_property_serial(rt->_pi);
         goto RESET_STATE;
     }
 
diff --git a/tests/Android.mk b/tests/Android.mk
index 875746d..c65d20c 100644
--- a/tests/Android.mk
+++ b/tests/Android.mk
@@ -31,6 +31,7 @@
 benchmark_src_files = \
     benchmark_main.cpp \
     math_benchmark.cpp \
+    property_benchmark.cpp \
     string_benchmark.cpp \
     time_benchmark.cpp \
 
@@ -78,6 +79,7 @@
     string_test.cpp \
     strings_test.cpp \
     stubs_test.cpp \
+    system_properties_test.cpp \
     time_test.cpp \
     unistd_test.cpp \
 
diff --git a/tests/property_benchmark.cpp b/tests/property_benchmark.cpp
new file mode 100644
index 0000000..dbd11ad
--- /dev/null
+++ b/tests/property_benchmark.cpp
@@ -0,0 +1,116 @@
+/*
+ * Copyright (C) 2012 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 "benchmark.h"
+
+#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
+#include <sys/_system_properties.h>
+
+#include <vector>
+
+extern void *__system_property_area__;
+
+#define TEST_NUM_PROPS \
+    Arg(1)->Arg(4)->Arg(16)->Arg(64)->Arg(128)->Arg(247)
+
+struct LocalPropertyTestState {
+    LocalPropertyTestState(int nprops) : nprops(nprops) {
+        static const char prop_name_chars[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.-_";
+        old_pa = __system_property_area__;
+        pa = malloc(PA_SIZE);
+        __system_property_area_init(pa);
+
+        names = new char* [nprops];
+        name_lens = new int[nprops];
+        values = new char* [nprops];
+        value_lens = new int[nprops];
+
+        srandom(nprops);
+
+        for (int i = 0; i < nprops; i++) {
+            name_lens[i] = random() % PROP_NAME_MAX;
+            names[i] = new char[PROP_NAME_MAX + 1];
+            for (int j = 0; j < name_lens[i]; j++) {
+                names[i][j] = prop_name_chars[random() % (sizeof(prop_name_chars) - 1)];
+            }
+            names[i][name_lens[i]] = 0;
+            value_lens[i] = random() % PROP_VALUE_MAX;
+            values[i] = new char[PROP_VALUE_MAX];
+            for (int j = 0; j < value_lens[i]; j++) {
+                values[i][j] = prop_name_chars[random() % (sizeof(prop_name_chars) - 1)];
+            }
+            __system_property_add(names[i], name_lens[i], values[i], value_lens[i]);
+        }
+    }
+
+    ~LocalPropertyTestState() {
+        __system_property_area__ = old_pa;
+        for (int i = 0; i < nprops; i++) {
+            delete names[i];
+            delete values[i];
+        }
+        delete names;
+        delete name_lens;
+        delete values;
+        delete value_lens;
+        free(pa);
+    }
+public:
+    const int nprops;
+    char **names;
+    int *name_lens;
+    char **values;
+    int *value_lens;
+
+private:
+    void *pa;
+    void *old_pa;
+};
+
+static void BM_property_get(int iters, int nprops)
+{
+    StopBenchmarkTiming();
+
+    LocalPropertyTestState pa(nprops);
+    char value[PROP_VALUE_MAX];
+
+    StartBenchmarkTiming();
+
+    for (int i = 0; i < iters; i++) {
+        for (int j = 0; j < nprops; j++) {
+            __system_property_get(pa.names[j], value);
+        }
+    }
+    StopBenchmarkTiming();
+}
+BENCHMARK(BM_property_get)->TEST_NUM_PROPS;
+
+static void BM_property_find(int iters, int nprops)
+{
+    StopBenchmarkTiming();
+
+    LocalPropertyTestState pa(nprops);
+
+    StartBenchmarkTiming();
+
+    for (int i = 0; i < iters; i++) {
+        for (int j = 0; j < nprops; j++) {
+            __system_property_find(pa.names[j]);
+        }
+    }
+    StopBenchmarkTiming();
+}
+BENCHMARK(BM_property_find)->TEST_NUM_PROPS;
diff --git a/tests/system_properties_test.cpp b/tests/system_properties_test.cpp
new file mode 100644
index 0000000..60188f4
--- /dev/null
+++ b/tests/system_properties_test.cpp
@@ -0,0 +1,229 @@
+/*
+ * 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 <sys/wait.h>
+
+#if __BIONIC__
+
+#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
+#include <sys/_system_properties.h>
+
+extern void *__system_property_area__;
+
+struct LocalPropertyTestState {
+    LocalPropertyTestState() {
+        old_pa = __system_property_area__;
+        pa = malloc(PA_SIZE);
+        __system_property_area_init(pa);
+    }
+
+    ~LocalPropertyTestState() {
+        __system_property_area__ = old_pa;
+        free(pa);
+    }
+private:
+    void *pa;
+    void *old_pa;
+};
+
+TEST(properties, add) {
+    LocalPropertyTestState pa;
+
+    char propvalue[PROP_VALUE_MAX];
+
+    ASSERT_EQ(0, __system_property_add("property", 8, "value1", 6));
+    ASSERT_EQ(0, __system_property_add("other_property", 14, "value2", 6));
+    ASSERT_EQ(0, __system_property_add("property_other", 14, "value3", 6));
+
+    ASSERT_EQ(6, __system_property_get("property", propvalue));
+    ASSERT_STREQ(propvalue, "value1");
+
+    ASSERT_EQ(6, __system_property_get("other_property", propvalue));
+    ASSERT_STREQ(propvalue, "value2");
+
+    ASSERT_EQ(6, __system_property_get("property_other", propvalue));
+    ASSERT_STREQ(propvalue, "value3");
+}
+
+TEST(properties, update) {
+    LocalPropertyTestState pa;
+
+    char propvalue[PROP_VALUE_MAX];
+    prop_info *pi;
+
+    ASSERT_EQ(0, __system_property_add("property", 8, "oldvalue1", 9));
+    ASSERT_EQ(0, __system_property_add("other_property", 14, "value2", 6));
+    ASSERT_EQ(0, __system_property_add("property_other", 14, "value3", 6));
+
+    pi = (prop_info *)__system_property_find("property");
+    ASSERT_NE((prop_info *)NULL, pi);
+    __system_property_update(pi, "value4", 6);
+
+    pi = (prop_info *)__system_property_find("other_property");
+    ASSERT_NE((prop_info *)NULL, pi);
+    __system_property_update(pi, "newvalue5", 9);
+
+    pi = (prop_info *)__system_property_find("property_other");
+    ASSERT_NE((prop_info *)NULL, pi);
+    __system_property_update(pi, "value6", 6);
+
+    ASSERT_EQ(6, __system_property_get("property", propvalue));
+    ASSERT_STREQ(propvalue, "value4");
+
+    ASSERT_EQ(9, __system_property_get("other_property", propvalue));
+    ASSERT_STREQ(propvalue, "newvalue5");
+
+    ASSERT_EQ(6, __system_property_get("property_other", propvalue));
+    ASSERT_STREQ(propvalue, "value6");
+}
+
+// 247 = max # of properties supported by current implementation
+// (this should never go down)
+TEST(properties, fill_247) {
+    LocalPropertyTestState pa;
+    char prop_name[PROP_NAME_MAX];
+    char prop_value[PROP_VALUE_MAX];
+    char prop_value_ret[PROP_VALUE_MAX];
+    int ret;
+
+    for (int i = 0; i < 247; i++) {
+        ret = snprintf(prop_name, PROP_NAME_MAX - 1, "property_%d", i);
+        memset(prop_name + ret, 'a', PROP_NAME_MAX - 1 - ret);
+        ret = snprintf(prop_value, PROP_VALUE_MAX - 1, "value_%d", i);
+        memset(prop_value + ret, 'b', PROP_VALUE_MAX - 1 - ret);
+        prop_name[PROP_NAME_MAX - 1] = 0;
+        prop_value[PROP_VALUE_MAX - 1] = 0;
+
+        ASSERT_EQ(0, __system_property_add(prop_name, PROP_NAME_MAX - 1, prop_value, PROP_VALUE_MAX - 1));
+    }
+
+    for (int i = 0; i < 247; i++) {
+        ret = snprintf(prop_name, PROP_NAME_MAX - 1, "property_%d", i);
+        memset(prop_name + ret, 'a', PROP_NAME_MAX - 1 - ret);
+        ret = snprintf(prop_value, PROP_VALUE_MAX - 1, "value_%d", i);
+        memset(prop_value + ret, 'b', PROP_VALUE_MAX - 1 - ret);
+        prop_name[PROP_NAME_MAX - 1] = 0;
+        prop_value[PROP_VALUE_MAX - 1] = 0;
+        memset(prop_value_ret, '\0', PROP_VALUE_MAX);
+
+        ASSERT_EQ(PROP_VALUE_MAX - 1, __system_property_get(prop_name, prop_value_ret));
+        ASSERT_EQ(0, memcmp(prop_value, prop_value_ret, PROP_VALUE_MAX));
+    }
+}
+
+TEST(properties, find_nth) {
+    LocalPropertyTestState pa;
+
+    ASSERT_EQ(0, __system_property_add("property", 8, "value1", 6));
+    ASSERT_EQ(0, __system_property_add("other_property", 14, "value2", 6));
+    ASSERT_EQ(0, __system_property_add("property_other", 14, "value3", 6));
+
+    ASSERT_NE((const prop_info *)NULL, __system_property_find_nth(0));
+    ASSERT_NE((const prop_info *)NULL, __system_property_find_nth(1));
+    ASSERT_NE((const prop_info *)NULL, __system_property_find_nth(2));
+
+    ASSERT_EQ((const prop_info *)NULL, __system_property_find_nth(3));
+    ASSERT_EQ((const prop_info *)NULL, __system_property_find_nth(4));
+    ASSERT_EQ((const prop_info *)NULL, __system_property_find_nth(5));
+    ASSERT_EQ((const prop_info *)NULL, __system_property_find_nth(100));
+    ASSERT_EQ((const prop_info *)NULL, __system_property_find_nth(200));
+    ASSERT_EQ((const prop_info *)NULL, __system_property_find_nth(247));
+}
+
+TEST(properties, errors) {
+    LocalPropertyTestState pa;
+    char prop_value[PROP_NAME_MAX];
+
+    ASSERT_EQ(0, __system_property_add("property", 8, "value1", 6));
+    ASSERT_EQ(0, __system_property_add("other_property", 14, "value2", 6));
+    ASSERT_EQ(0, __system_property_add("property_other", 14, "value3", 6));
+
+    ASSERT_EQ(0, __system_property_find("property1"));
+    ASSERT_EQ(0, __system_property_get("property1", prop_value));
+
+    ASSERT_EQ(-1, __system_property_add("name", PROP_NAME_MAX, "value", 5));
+    ASSERT_EQ(-1, __system_property_add("name", 4, "value", PROP_VALUE_MAX));
+    ASSERT_EQ(-1, __system_property_update(NULL, "value", PROP_VALUE_MAX));
+}
+
+TEST(properties, serial) {
+    LocalPropertyTestState pa;
+    const prop_info *pi;
+    unsigned int serial;
+
+    ASSERT_EQ(0, __system_property_add("property", 8, "value1", 6));
+    ASSERT_NE((const prop_info *)NULL, pi = __system_property_find("property"));
+    serial = __system_property_serial(pi);
+    ASSERT_EQ(0, __system_property_update((prop_info *)pi, "value2", 6));
+    ASSERT_NE(serial, __system_property_serial(pi));
+}
+
+static void *PropertyWaitHelperFn(void *arg)
+{
+    int *flag = (int *)arg;
+    prop_info *pi;
+    pi = (prop_info *)__system_property_find("property");
+    usleep(100000);
+
+    *flag = 1;
+    __system_property_update(pi, "value3", 6);
+
+    return NULL;
+}
+
+TEST(properties, wait) {
+    LocalPropertyTestState pa;
+    unsigned int serial;
+    prop_info *pi;
+    pthread_t t;
+    int flag = 0;
+
+    ASSERT_EQ(0, __system_property_add("property", 8, "value1", 6));
+    serial = __system_property_wait_any(0);
+    pi = (prop_info *)__system_property_find("property");
+    ASSERT_NE((prop_info *)NULL, pi);
+    __system_property_update(pi, "value2", 6);
+    serial = __system_property_wait_any(serial);
+
+    ASSERT_EQ(0, pthread_create(&t, NULL, PropertyWaitHelperFn, &flag));
+    ASSERT_EQ(flag, 0);
+    serial = __system_property_wait_any(serial);
+    ASSERT_EQ(flag, 1);
+
+    void* result;
+    ASSERT_EQ(0, pthread_join(t, &result));
+}
+
+class KilledByFault {
+    public:
+        explicit KilledByFault() {};
+        bool operator()(int exit_status) const;
+};
+
+bool KilledByFault::operator()(int exit_status) const {
+    return WIFSIGNALED(exit_status) &&
+        (WTERMSIG(exit_status) == SIGSEGV ||
+         WTERMSIG(exit_status) == SIGBUS ||
+         WTERMSIG(exit_status) == SIGABRT);
+}
+
+TEST(properties_DeathTest, read_only) {
+      ::testing::FLAGS_gtest_death_test_style = "threadsafe";
+      ASSERT_EXIT(__system_property_add("property", 8, "value", 5),
+                  KilledByFault(), "");
+}
+#endif