diff --git a/cmds/keystore/Android.mk b/cmds/keystore/Android.mk
index 15a199f..67dd9f8 100644
--- a/cmds/keystore/Android.mk
+++ b/cmds/keystore/Android.mk
@@ -19,14 +19,14 @@
 LOCAL_PATH:= $(call my-dir)
 
 include $(CLEAR_VARS)
-LOCAL_SRC_FILES := keystore.c
+LOCAL_SRC_FILES := keystore.cpp
 LOCAL_C_INCLUDES := external/openssl/include
 LOCAL_SHARED_LIBRARIES := libcutils libcrypto
 LOCAL_MODULE:= keystore
 include $(BUILD_EXECUTABLE)
 
 include $(CLEAR_VARS)
-LOCAL_SRC_FILES := keystore_cli.c
+LOCAL_SRC_FILES := keystore_cli.cpp
 LOCAL_C_INCLUDES := external/openssl/include
 LOCAL_SHARED_LIBRARIES := libcutils libcrypto
 LOCAL_MODULE:= keystore_cli
diff --git a/cmds/keystore/keystore.c b/cmds/keystore/keystore.c
deleted file mode 100644
index e34053b..0000000
--- a/cmds/keystore/keystore.c
+++ /dev/null
@@ -1,590 +0,0 @@
-/*
- * Copyright (C) 2009 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 <stdio.h>
-#include <stdint.h>
-#include <string.h>
-#include <unistd.h>
-#include <signal.h>
-#include <errno.h>
-#include <dirent.h>
-#include <fcntl.h>
-#include <limits.h>
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <sys/stat.h>
-#include <sys/time.h>
-#include <arpa/inet.h>
-
-#include <openssl/aes.h>
-#include <openssl/evp.h>
-#include <openssl/md5.h>
-
-#define LOG_TAG "keystore"
-#include <cutils/log.h>
-#include <cutils/sockets.h>
-#include <private/android_filesystem_config.h>
-
-#include "keystore.h"
-
-/* KeyStore is a secured storage for key-value pairs. In this implementation,
- * each file stores one key-value pair. Keys are encoded in file names, and
- * values are encrypted with checksums. The encryption key is protected by a
- * user-defined password. To keep things simple, buffers are always larger than
- * the maximum space we needed, so boundary checks on buffers are omitted. */
-
-#define KEY_SIZE        ((NAME_MAX - 15) / 2)
-#define VALUE_SIZE      32768
-#define PASSWORD_SIZE   VALUE_SIZE
-
-/* Here is the encoding of keys. This is necessary in order to allow arbitrary
- * characters in keys. Characters in [0-~] are not encoded. Others are encoded
- * into two bytes. The first byte is one of [+-.] which represents the first
- * two bits of the character. The second byte encodes the rest of the bits into
- * [0-o]. Therefore in the worst case the length of a key gets doubled. Note
- * that Base64 cannot be used here due to the need of prefix match on keys. */
-
-static int encode_key(char *out, uint8_t *in, int length)
-{
-    int i;
-    for (i = length; i > 0; --i, ++in, ++out) {
-        if (*in >= '0' && *in <= '~') {
-            *out = *in;
-        } else {
-            *out = '+' + (*in >> 6);
-            *++out = '0' + (*in & 0x3F);
-            ++length;
-        }
-    }
-    *out = 0;
-    return length;
-}
-
-static int decode_key(uint8_t *out, char *in, int length)
-{
-    int i;
-    for (i = 0; i < length; ++i, ++in, ++out) {
-        if (*in >= '0' && *in <= '~') {
-            *out = *in;
-        } else {
-            *out = (*in - '+') << 6;
-            *out |= (*++in - '0') & 0x3F;
-            --length;
-        }
-    }
-    *out = 0;
-    return length;
-}
-
-/* Here is the protocol used in both requests and responses:
- *     code [length_1 message_1 ... length_n message_n] end-of-file
- * where code is one byte long and lengths are unsigned 16-bit integers in
- * network order. Thus the maximum length of a message is 65535 bytes. */
-
-static int the_socket = -1;
-
-static int recv_code(int8_t *code)
-{
-    return recv(the_socket, code, 1, 0) == 1;
-}
-
-static int recv_message(uint8_t *message, int length)
-{
-    uint8_t bytes[2];
-    if (recv(the_socket, &bytes[0], 1, 0) != 1 ||
-        recv(the_socket, &bytes[1], 1, 0) != 1) {
-        return -1;
-    } else {
-        int offset = bytes[0] << 8 | bytes[1];
-        if (length < offset) {
-            return -1;
-        }
-        length = offset;
-        offset = 0;
-        while (offset < length) {
-            int n = recv(the_socket, &message[offset], length - offset, 0);
-            if (n <= 0) {
-                return -1;
-            }
-            offset += n;
-        }
-    }
-    return length;
-}
-
-static int recv_end_of_file()
-{
-    uint8_t byte;
-    return recv(the_socket, &byte, 1, 0) == 0;
-}
-
-static void send_code(int8_t code)
-{
-    send(the_socket, &code, 1, 0);
-}
-
-static void send_message(uint8_t *message, int length)
-{
-    uint16_t bytes = htons(length);
-    send(the_socket, &bytes, 2, 0);
-    send(the_socket, message, length, 0);
-}
-
-/* Here is the file format. There are two parts in blob.value, the secret and
- * the description. The secret is stored in ciphertext, and its original size
- * can be found in blob.length. The description is stored after the secret in
- * plaintext, and its size is specified in blob.info. The total size of the two
- * parts must be no more than VALUE_SIZE bytes. The first three bytes of the
- * file are reserved for future use and are always set to zero. Fields other
- * than blob.info, blob.length, and blob.value are modified by encrypt_blob()
- * and decrypt_blob(). Thus they should not be accessed from outside. */
-
-static int the_entropy = -1;
-
-static struct __attribute__((packed)) {
-    uint8_t reserved[3];
-    uint8_t info;
-    uint8_t vector[AES_BLOCK_SIZE];
-    uint8_t encrypted[0];
-    uint8_t digest[MD5_DIGEST_LENGTH];
-    uint8_t digested[0];
-    int32_t length;
-    uint8_t value[VALUE_SIZE + AES_BLOCK_SIZE];
-} blob;
-
-static int8_t encrypt_blob(char *name, AES_KEY *aes_key)
-{
-    uint8_t vector[AES_BLOCK_SIZE];
-    int length;
-    int fd;
-
-    if (read(the_entropy, blob.vector, AES_BLOCK_SIZE) != AES_BLOCK_SIZE) {
-        return SYSTEM_ERROR;
-    }
-
-    length = blob.length + (blob.value - blob.encrypted);
-    length = (length + AES_BLOCK_SIZE - 1) / AES_BLOCK_SIZE * AES_BLOCK_SIZE;
-
-    if (blob.info != 0) {
-        memmove(&blob.encrypted[length], &blob.value[blob.length], blob.info);
-    }
-
-    blob.length = htonl(blob.length);
-    MD5(blob.digested, length - (blob.digested - blob.encrypted), blob.digest);
-
-    memcpy(vector, blob.vector, AES_BLOCK_SIZE);
-    AES_cbc_encrypt(blob.encrypted, blob.encrypted, length, aes_key, vector,
-                    AES_ENCRYPT);
-
-    memset(blob.reserved, 0, sizeof(blob.reserved));
-    length += (blob.encrypted - (uint8_t *)&blob) + blob.info;
-
-    fd = open(".tmp", O_WRONLY | O_TRUNC | O_CREAT, S_IRUSR | S_IWUSR);
-    length -= write(fd, &blob, length);
-    close(fd);
-    return (length || rename(".tmp", name)) ? SYSTEM_ERROR : NO_ERROR;
-}
-
-static int8_t decrypt_blob(char *name, AES_KEY *aes_key)
-{
-    int fd = open(name, O_RDONLY);
-    int length;
-
-    if (fd == -1) {
-        return (errno == ENOENT) ? KEY_NOT_FOUND : SYSTEM_ERROR;
-    }
-    length = read(fd, &blob, sizeof(blob));
-    close(fd);
-
-    length -= (blob.encrypted - (uint8_t *)&blob) + blob.info;
-    if (length < blob.value - blob.encrypted || length % AES_BLOCK_SIZE != 0) {
-        return VALUE_CORRUPTED;
-    }
-
-    AES_cbc_encrypt(blob.encrypted, blob.encrypted, length, aes_key,
-                    blob.vector, AES_DECRYPT);
-    length -= blob.digested - blob.encrypted;
-    if (memcmp(blob.digest, MD5(blob.digested, length, NULL),
-               MD5_DIGEST_LENGTH)) {
-        return VALUE_CORRUPTED;
-    }
-
-    length -= blob.value - blob.digested;
-    blob.length = ntohl(blob.length);
-    if (blob.length < 0 || blob.length > length) {
-        return VALUE_CORRUPTED;
-    }
-    if (blob.info != 0) {
-        memmove(&blob.value[blob.length], &blob.value[length], blob.info);
-    }
-    return NO_ERROR;
-}
-
-/* Here are the actions. Each of them is a function without arguments. All
- * information is defined in global variables, which are set properly before
- * performing an action. The number of parameters required by each action is
- * fixed and defined in a table. If the return value of an action is positive,
- * it will be treated as a response code and transmitted to the client. Note
- * that the lengths of parameters are checked when they are received, so
- * boundary checks on parameters are omitted. */
-
-#define MAX_PARAM   2
-#define MAX_RETRY   4
-
-static uid_t uid = -1;
-static int8_t state = UNINITIALIZED;
-static int8_t retry = MAX_RETRY;
-
-static struct {
-    int length;
-    uint8_t value[VALUE_SIZE];
-} params[MAX_PARAM];
-
-static AES_KEY encryption_key;
-static AES_KEY decryption_key;
-
-static int8_t test()
-{
-    return state;
-}
-
-static int8_t get()
-{
-    char name[NAME_MAX];
-    int n = sprintf(name, "%u_", uid);
-    encode_key(&name[n], params[0].value, params[0].length);
-    n = decrypt_blob(name, &decryption_key);
-    if (n != NO_ERROR) {
-        return n;
-    }
-    send_code(NO_ERROR);
-    send_message(blob.value, blob.length);
-    return -NO_ERROR;
-}
-
-static int8_t insert()
-{
-    char name[NAME_MAX];
-    int n = sprintf(name, "%u_", uid);
-    encode_key(&name[n], params[0].value, params[0].length);
-    blob.info = 0;
-    blob.length = params[1].length;
-    memcpy(blob.value, params[1].value, params[1].length);
-    return encrypt_blob(name, &encryption_key);
-}
-
-static int8_t delete()
-{
-    char name[NAME_MAX];
-    int n = sprintf(name, "%u_", uid);
-    encode_key(&name[n], params[0].value, params[0].length);
-    return (unlink(name) && errno != ENOENT) ? SYSTEM_ERROR : NO_ERROR;
-}
-
-static int8_t exist()
-{
-    char name[NAME_MAX];
-    int n = sprintf(name, "%u_", uid);
-    encode_key(&name[n], params[0].value, params[0].length);
-    if (access(name, R_OK) == -1) {
-        return (errno != ENOENT) ? SYSTEM_ERROR : KEY_NOT_FOUND;
-    }
-    return NO_ERROR;
-}
-
-static int8_t saw()
-{
-    DIR *dir = opendir(".");
-    struct dirent *file;
-    char name[NAME_MAX];
-    int n;
-
-    if (!dir) {
-        return SYSTEM_ERROR;
-    }
-    n = sprintf(name, "%u_", uid);
-    n += encode_key(&name[n], params[0].value, params[0].length);
-    send_code(NO_ERROR);
-    while ((file = readdir(dir)) != NULL) {
-        if (!strncmp(name, file->d_name, n)) {
-            char *p = &file->d_name[n];
-            params[0].length = decode_key(params[0].value, p, strlen(p));
-            send_message(params[0].value, params[0].length);
-        }
-    }
-    closedir(dir);
-    return -NO_ERROR;
-}
-
-static int8_t reset()
-{
-    DIR *dir = opendir(".");
-    struct dirent *file;
-
-    memset(&encryption_key, 0, sizeof(encryption_key));
-    memset(&decryption_key, 0, sizeof(decryption_key));
-    state = UNINITIALIZED;
-    retry = MAX_RETRY;
-
-    if (!dir) {
-        return SYSTEM_ERROR;
-    }
-    while ((file = readdir(dir)) != NULL) {
-        unlink(file->d_name);
-    }
-    closedir(dir);
-    return NO_ERROR;
-}
-
-#define MASTER_KEY_FILE ".masterkey"
-#define MASTER_KEY_SIZE 16
-#define SALT_SIZE       16
-
-static void set_key(uint8_t *key, uint8_t *password, int length, uint8_t *salt)
-{
-    if (salt) {
-        PKCS5_PBKDF2_HMAC_SHA1((char *)password, length, salt, SALT_SIZE,
-                               8192, MASTER_KEY_SIZE, key);
-    } else {
-        PKCS5_PBKDF2_HMAC_SHA1((char *)password, length, (uint8_t *)"keystore",
-                               sizeof("keystore"), 1024, MASTER_KEY_SIZE, key);
-    }
-}
-
-/* Here is the history. To improve the security, the parameters to generate the
- * master key has been changed. To make a seamless transition, we update the
- * file using the same password when the user unlock it for the first time. If
- * any thing goes wrong during the transition, the new file will not overwrite
- * the old one. This avoids permanent damages of the existing data. */
-
-static int8_t password()
-{
-    uint8_t key[MASTER_KEY_SIZE];
-    AES_KEY aes_key;
-    int8_t response = SYSTEM_ERROR;
-
-    if (state == UNINITIALIZED) {
-        if (read(the_entropy, blob.value, MASTER_KEY_SIZE) != MASTER_KEY_SIZE) {
-           return SYSTEM_ERROR;
-        }
-    } else {
-        int fd = open(MASTER_KEY_FILE, O_RDONLY);
-        uint8_t *salt = NULL;
-        if (fd != -1) {
-            int length = read(fd, &blob, sizeof(blob));
-            close(fd);
-            if (length > SALT_SIZE && blob.info == SALT_SIZE) {
-                salt = (uint8_t *)&blob + length - SALT_SIZE;
-            }
-        }
-
-        set_key(key, params[0].value, params[0].length, salt);
-        AES_set_decrypt_key(key, MASTER_KEY_SIZE * 8, &aes_key);
-        response = decrypt_blob(MASTER_KEY_FILE, &aes_key);
-        if (response == SYSTEM_ERROR) {
-            return SYSTEM_ERROR;
-        }
-        if (response != NO_ERROR || blob.length != MASTER_KEY_SIZE) {
-            if (retry <= 0) {
-                reset();
-                return UNINITIALIZED;
-            }
-            return WRONG_PASSWORD + --retry;
-        }
-
-        if (!salt && params[1].length == -1) {
-            params[1] = params[0];
-        }
-    }
-
-    if (params[1].length == -1) {
-        memcpy(key, blob.value, MASTER_KEY_SIZE);
-    } else {
-        uint8_t *salt = &blob.value[MASTER_KEY_SIZE];
-        if (read(the_entropy, salt, SALT_SIZE) != SALT_SIZE) {
-            return SYSTEM_ERROR;
-        }
-
-        set_key(key, params[1].value, params[1].length, salt);
-        AES_set_encrypt_key(key, MASTER_KEY_SIZE * 8, &aes_key);
-        memcpy(key, blob.value, MASTER_KEY_SIZE);
-        blob.info = SALT_SIZE;
-        blob.length = MASTER_KEY_SIZE;
-        response = encrypt_blob(MASTER_KEY_FILE, &aes_key);
-    }
-
-    if (response == NO_ERROR) {
-        AES_set_encrypt_key(key, MASTER_KEY_SIZE * 8, &encryption_key);
-        AES_set_decrypt_key(key, MASTER_KEY_SIZE * 8, &decryption_key);
-        state = NO_ERROR;
-        retry = MAX_RETRY;
-    }
-    return response;
-}
-
-static int8_t lock()
-{
-    memset(&encryption_key, 0, sizeof(encryption_key));
-    memset(&decryption_key, 0, sizeof(decryption_key));
-    state = LOCKED;
-    return NO_ERROR;
-}
-
-static int8_t unlock()
-{
-    params[1].length = -1;
-    return password();
-}
-
-/* Here are the permissions, actions, users, and the main function. */
-
-enum perm {
-    TEST     =   1,
-    GET      =   2,
-    INSERT   =   4,
-    DELETE   =   8,
-    EXIST    =  16,
-    SAW      =  32,
-    RESET    =  64,
-    PASSWORD = 128,
-    LOCK     = 256,
-    UNLOCK   = 512,
-};
-
-static struct action {
-    int8_t (*run)();
-    int8_t code;
-    int8_t state;
-    uint32_t perm;
-    int lengths[MAX_PARAM];
-} actions[] = {
-    {test,     't', 0,        TEST,     {0}},
-    {get,      'g', NO_ERROR, GET,      {KEY_SIZE}},
-    {insert,   'i', NO_ERROR, INSERT,   {KEY_SIZE, VALUE_SIZE}},
-    {delete,   'd', 0,        DELETE,   {KEY_SIZE}},
-    {exist,    'e', 0,        EXIST,    {KEY_SIZE}},
-    {saw,      's', 0,        SAW,      {KEY_SIZE}},
-    {reset,    'r', 0,        RESET,    {0}},
-    {password, 'p', 0,        PASSWORD, {PASSWORD_SIZE, PASSWORD_SIZE}},
-    {lock,     'l', NO_ERROR, LOCK,     {0}},
-    {unlock,   'u', LOCKED,   UNLOCK,   {PASSWORD_SIZE}},
-    {NULL,      0 , 0,        0,        {0}},
-};
-
-static struct user {
-    uid_t uid;
-    uid_t euid;
-    uint32_t perms;
-} users[] = {
-    {AID_SYSTEM,   ~0,         ~GET},
-    {AID_VPN,      AID_SYSTEM, GET},
-    {AID_WIFI,     AID_SYSTEM, GET},
-    {AID_ROOT,     AID_SYSTEM, GET},
-    {AID_KEYCHAIN, AID_SYSTEM, TEST | GET | SAW},
-    {~0,           ~0,         TEST | GET | INSERT | DELETE | EXIST | SAW},
-};
-
-static int8_t process(int8_t code) {
-    struct user *user = users;
-    struct action *action = actions;
-    int i;
-
-    while (~user->uid && user->uid != uid) {
-        ++user;
-    }
-    while (action->code && action->code != code) {
-        ++action;
-    }
-    if (!action->code) {
-        return UNDEFINED_ACTION;
-    }
-    if (!(action->perm & user->perms)) {
-        return PERMISSION_DENIED;
-    }
-    if (action->state && action->state != state) {
-        return state;
-    }
-    if (~user->euid) {
-        uid = user->euid;
-    }
-    for (i = 0; i < MAX_PARAM && action->lengths[i]; ++i) {
-        params[i].length = recv_message(params[i].value, action->lengths[i]);
-        if (params[i].length == -1) {
-            return PROTOCOL_ERROR;
-        }
-    }
-    if (!recv_end_of_file()) {
-        return PROTOCOL_ERROR;
-    }
-    return action->run();
-}
-
-#define RANDOM_DEVICE   "/dev/urandom"
-
-int main(int argc, char **argv)
-{
-    int control_socket = android_get_control_socket("keystore");
-    if (argc < 2) {
-        LOGE("A directory must be specified!");
-        return 1;
-    }
-    if (chdir(argv[1]) == -1) {
-        LOGE("chdir: %s: %s", argv[1], strerror(errno));
-        return 1;
-    }
-    if ((the_entropy = open(RANDOM_DEVICE, O_RDONLY)) == -1) {
-        LOGE("open: %s: %s", RANDOM_DEVICE, strerror(errno));
-        return 1;
-    }
-    if (listen(control_socket, 3) == -1) {
-        LOGE("listen: %s", strerror(errno));
-        return 1;
-    }
-
-    signal(SIGPIPE, SIG_IGN);
-    if (access(MASTER_KEY_FILE, R_OK) == 0) {
-        state = LOCKED;
-    }
-
-    while ((the_socket = accept(control_socket, NULL, 0)) != -1) {
-        struct timeval tv = {.tv_sec = 3};
-        struct ucred cred;
-        socklen_t size = sizeof(cred);
-        int8_t request;
-
-        setsockopt(the_socket, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
-        setsockopt(the_socket, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
-
-        if (getsockopt(the_socket, SOL_SOCKET, SO_PEERCRED, &cred, &size)) {
-            LOGW("getsockopt: %s", strerror(errno));
-        } else if (recv_code(&request)) {
-            int8_t old_state = state;
-            int8_t response;
-            uid = cred.uid;
-
-            if ((response = process(request)) > 0) {
-                send_code(response);
-                response = -response;
-            }
-
-            LOGI("uid: %d action: %c -> %d state: %d -> %d retry: %d",
-                 cred.uid, request, -response, old_state, state, retry);
-        }
-        close(the_socket);
-    }
-    LOGE("accept: %s", strerror(errno));
-    return 1;
-}
diff --git a/cmds/keystore/keystore.cpp b/cmds/keystore/keystore.cpp
new file mode 100644
index 0000000..31db9fd
--- /dev/null
+++ b/cmds/keystore/keystore.cpp
@@ -0,0 +1,812 @@
+/*
+ * Copyright (C) 2009 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 <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+#include <signal.h>
+#include <errno.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <arpa/inet.h>
+
+#include <openssl/aes.h>
+#include <openssl/evp.h>
+#include <openssl/md5.h>
+
+#define LOG_TAG "keystore"
+#include <cutils/log.h>
+#include <cutils/sockets.h>
+#include <private/android_filesystem_config.h>
+
+#include "keystore.h"
+
+/* KeyStore is a secured storage for key-value pairs. In this implementation,
+ * each file stores one key-value pair. Keys are encoded in file names, and
+ * values are encrypted with checksums. The encryption key is protected by a
+ * user-defined password. To keep things simple, buffers are always larger than
+ * the maximum space we needed, so boundary checks on buffers are omitted. */
+
+#define KEY_SIZE        ((NAME_MAX - 15) / 2)
+#define VALUE_SIZE      32768
+#define PASSWORD_SIZE   VALUE_SIZE
+
+struct Value {
+    int length;
+    uint8_t value[VALUE_SIZE];
+};
+
+/* Here is the encoding of keys. This is necessary in order to allow arbitrary
+ * characters in keys. Characters in [0-~] are not encoded. Others are encoded
+ * into two bytes. The first byte is one of [+-.] which represents the first
+ * two bits of the character. The second byte encodes the rest of the bits into
+ * [0-o]. Therefore in the worst case the length of a key gets doubled. Note
+ * that Base64 cannot be used here due to the need of prefix match on keys. */
+
+static int encode_key(char* out, uid_t uid, const Value* key) {
+    int n = snprintf(out, NAME_MAX, "%u_", uid);
+    out += n;
+    const uint8_t* in = key->value;
+    int length = key->length;
+    for (int i = length; i > 0; --i, ++in, ++out) {
+        if (*in >= '0' && *in <= '~') {
+            *out = *in;
+        } else {
+            *out = '+' + (*in >> 6);
+            *++out = '0' + (*in & 0x3F);
+            ++length;
+        }
+    }
+    *out = '\0';
+    return n + length;
+}
+
+static int decode_key(uint8_t* out, char* in, int length) {
+    for (int i = 0; i < length; ++i, ++in, ++out) {
+        if (*in >= '0' && *in <= '~') {
+            *out = *in;
+        } else {
+            *out = (*in - '+') << 6;
+            *out |= (*++in - '0') & 0x3F;
+            --length;
+        }
+    }
+    *out = '\0';
+    return length;
+}
+
+static size_t readFully(int fd, uint8_t* data, size_t size) {
+    size_t remaining = size;
+    while (remaining > 0) {
+        ssize_t n = TEMP_FAILURE_RETRY(read(fd, data, size));
+        if (n == -1 || n == 0) {
+            return size-remaining;
+        }
+        data += n;
+        remaining -= n;
+    }
+    return size;
+}
+
+static size_t writeFully(int fd, uint8_t* data, size_t size) {
+    size_t remaining = size;
+    while (remaining > 0) {
+        ssize_t n = TEMP_FAILURE_RETRY(write(fd, data, size));
+        if (n == -1 || n == 0) {
+            return size-remaining;
+        }
+        data += n;
+        remaining -= n;
+    }
+    return size;
+}
+
+class Entropy {
+public:
+    Entropy() : mRandom(-1) {}
+    ~Entropy() {
+        if (mRandom != -1) {
+            close(mRandom);
+        }
+    }
+
+    bool open() {
+        const char* randomDevice = "/dev/urandom";
+        mRandom = ::open(randomDevice, O_RDONLY);
+        if (mRandom == -1) {
+            LOGE("open: %s: %s", randomDevice, strerror(errno));
+            return false;
+        }
+        return true;
+    }
+
+    bool generate_random_data(uint8_t* data, size_t size) {
+        return (readFully(mRandom, data, size) == size);
+    }
+
+private:
+    int mRandom;
+};
+
+/* Here is the file format. There are two parts in blob.value, the secret and
+ * the description. The secret is stored in ciphertext, and its original size
+ * can be found in blob.length. The description is stored after the secret in
+ * plaintext, and its size is specified in blob.info. The total size of the two
+ * parts must be no more than VALUE_SIZE bytes. The first three bytes of the
+ * file are reserved for future use and are always set to zero. Fields other
+ * than blob.info, blob.length, and blob.value are modified by encryptBlob()
+ * and decryptBlob(). Thus they should not be accessed from outside. */
+
+struct __attribute__((packed)) blob {
+    uint8_t reserved[3];
+    uint8_t info;
+    uint8_t vector[AES_BLOCK_SIZE];
+    uint8_t encrypted[0];
+    uint8_t digest[MD5_DIGEST_LENGTH];
+    uint8_t digested[0];
+    int32_t length; // in network byte order when encrypted
+    uint8_t value[VALUE_SIZE + AES_BLOCK_SIZE];
+};
+
+class Blob {
+public:
+    Blob(uint8_t* value, int32_t valueLength, uint8_t* info, uint8_t infoLength) {
+        mBlob.length = valueLength;
+        memcpy(mBlob.value, value, valueLength);
+
+        mBlob.info = infoLength;
+        memcpy(mBlob.value + valueLength, info, infoLength);
+    }
+
+    Blob(blob b) {
+        mBlob = b;
+    }
+
+    Blob() {}
+
+    uint8_t* getValue() {
+        return mBlob.value;
+    }
+
+    int32_t getLength() {
+        return mBlob.length;
+    }
+
+    uint8_t getInfo() {
+        return mBlob.info;
+    }
+
+    ResponseCode encryptBlob(const char* filename, AES_KEY *aes_key, Entropy* entropy) {
+        if (!entropy->generate_random_data(mBlob.vector, AES_BLOCK_SIZE)) {
+            return SYSTEM_ERROR;
+        }
+
+        // data includes the value and the value's length
+        size_t dataLength = mBlob.length + sizeof(mBlob.length);
+        // pad data to the AES_BLOCK_SIZE
+        size_t digestedLength = ((dataLength + AES_BLOCK_SIZE - 1)
+                                 / AES_BLOCK_SIZE * AES_BLOCK_SIZE);
+        // encrypted data includes the digest value
+        size_t encryptedLength = digestedLength + MD5_DIGEST_LENGTH;
+        // move info after space for padding
+        memmove(&mBlob.encrypted[encryptedLength], &mBlob.value[mBlob.length], mBlob.info);
+        // zero padding area
+        memset(mBlob.value + mBlob.length, 0, digestedLength - dataLength);
+
+        mBlob.length = htonl(mBlob.length);
+        MD5(mBlob.digested, digestedLength, mBlob.digest);
+
+        uint8_t vector[AES_BLOCK_SIZE];
+        memcpy(vector, mBlob.vector, AES_BLOCK_SIZE);
+        AES_cbc_encrypt(mBlob.encrypted, mBlob.encrypted, encryptedLength,
+                        aes_key, vector, AES_ENCRYPT);
+
+        memset(mBlob.reserved, 0, sizeof(mBlob.reserved));
+        size_t headerLength = (mBlob.encrypted - (uint8_t*) &mBlob);
+        size_t fileLength = encryptedLength + headerLength + mBlob.info;
+
+        const char* tmpFileName = ".tmp";
+        int out = open(tmpFileName, O_WRONLY | O_TRUNC | O_CREAT, S_IRUSR | S_IWUSR);
+        if (out == -1) {
+            return SYSTEM_ERROR;
+        }
+        size_t writtenBytes = writeFully(out, (uint8_t*) &mBlob, fileLength);
+        if (close(out) != 0) {
+            return SYSTEM_ERROR;
+        }
+        if (writtenBytes != fileLength) {
+            unlink(tmpFileName);
+            return SYSTEM_ERROR;
+        }
+        return (rename(tmpFileName, filename) == 0) ? NO_ERROR : SYSTEM_ERROR;
+    }
+
+    ResponseCode decryptBlob(const char* filename, AES_KEY *aes_key) {
+        int in = open(filename, O_RDONLY);
+        if (in == -1) {
+            return (errno == ENOENT) ? KEY_NOT_FOUND : SYSTEM_ERROR;
+        }
+        // fileLength may be less than sizeof(mBlob) since the in
+        // memory version has extra padding to tolerate rounding up to
+        // the AES_BLOCK_SIZE
+        size_t fileLength = readFully(in, (uint8_t*) &mBlob, sizeof(mBlob));
+        if (close(in) != 0) {
+            return SYSTEM_ERROR;
+        }
+        size_t headerLength = (mBlob.encrypted - (uint8_t*) &mBlob);
+        if (fileLength < headerLength) {
+            return VALUE_CORRUPTED;
+        }
+
+        ssize_t encryptedLength = fileLength - (headerLength + mBlob.info);
+        if (encryptedLength < 0 || encryptedLength % AES_BLOCK_SIZE != 0) {
+            return VALUE_CORRUPTED;
+        }
+        AES_cbc_encrypt(mBlob.encrypted, mBlob.encrypted, encryptedLength, aes_key,
+                        mBlob.vector, AES_DECRYPT);
+        size_t digestedLength = encryptedLength - MD5_DIGEST_LENGTH;
+        uint8_t computedDigest[MD5_DIGEST_LENGTH];
+        MD5(mBlob.digested, digestedLength, computedDigest);
+        if (memcmp(mBlob.digest, computedDigest, MD5_DIGEST_LENGTH) != 0) {
+            return VALUE_CORRUPTED;
+        }
+
+        ssize_t maxValueLength = digestedLength - sizeof(mBlob.length);
+        mBlob.length = ntohl(mBlob.length);
+        if (mBlob.length < 0 || mBlob.length > maxValueLength) {
+            return VALUE_CORRUPTED;
+        }
+        if (mBlob.info != 0) {
+            // move info from after padding to after data
+            memmove(&mBlob.value[mBlob.length], &mBlob.value[maxValueLength], mBlob.info);
+        }
+        return NO_ERROR;
+    }
+
+private:
+    struct blob mBlob;
+};
+
+class KeyStore {
+public:
+    KeyStore(Entropy* entropy) : mEntropy(entropy), mRetry(MAX_RETRY) {
+        if (access(MASTER_KEY_FILE, R_OK) == 0) {
+            setState(STATE_LOCKED);
+        } else {
+            setState(STATE_UNINITIALIZED);
+        }
+    }
+
+    State getState() {
+        return mState;
+    }
+
+    int8_t getRetry() {
+        return mRetry;
+    }
+
+    ResponseCode initialize(Value* pw) {
+        if (!generateMasterKey()) {
+            return SYSTEM_ERROR;
+        }
+        ResponseCode response = writeMasterKey(pw);
+        if (response != NO_ERROR) {
+            return response;
+        }
+        setupMasterKeys();
+        return NO_ERROR;
+    }
+
+    ResponseCode writeMasterKey(Value* pw) {
+        uint8_t passwordKey[MASTER_KEY_SIZE_BYTES];
+        generateKeyFromPassword(passwordKey, MASTER_KEY_SIZE_BYTES, pw, mSalt);
+        AES_KEY passwordAesKey;
+        AES_set_encrypt_key(passwordKey, MASTER_KEY_SIZE_BITS, &passwordAesKey);
+        Blob masterKeyBlob(mMasterKey, sizeof(mMasterKey), mSalt, sizeof(mSalt));
+        return masterKeyBlob.encryptBlob(MASTER_KEY_FILE, &passwordAesKey, mEntropy);
+    }
+
+    ResponseCode readMasterKey(Value* pw) {
+        int in = open(MASTER_KEY_FILE, O_RDONLY);
+        if (in == -1) {
+            return SYSTEM_ERROR;
+        }
+
+        // we read the raw blob to just to get the salt to generate
+        // the AES key, then we create the Blob to use with decryptBlob
+        blob rawBlob;
+        size_t length = readFully(in, (uint8_t*) &rawBlob, sizeof(rawBlob));
+        if (close(in) != 0) {
+            return SYSTEM_ERROR;
+        }
+        // find salt at EOF if present, otherwise we have an old file
+        uint8_t* salt;
+        if (length > SALT_SIZE && rawBlob.info == SALT_SIZE) {
+            salt = (uint8_t*) &rawBlob + length - SALT_SIZE;
+        } else {
+            salt = NULL;
+        }
+        uint8_t passwordKey[MASTER_KEY_SIZE_BYTES];
+        generateKeyFromPassword(passwordKey, MASTER_KEY_SIZE_BYTES, pw, salt);
+        AES_KEY passwordAesKey;
+        AES_set_decrypt_key(passwordKey, MASTER_KEY_SIZE_BITS, &passwordAesKey);
+        Blob masterKeyBlob(rawBlob);
+        ResponseCode response = masterKeyBlob.decryptBlob(MASTER_KEY_FILE, &passwordAesKey);
+        if (response == SYSTEM_ERROR) {
+            return SYSTEM_ERROR;
+        }
+        if (response == NO_ERROR && masterKeyBlob.getLength() == MASTER_KEY_SIZE_BYTES) {
+            // if salt was missing, generate one and write a new master key file with the salt.
+            if (salt == NULL) {
+                if (!generateSalt()) {
+                    return SYSTEM_ERROR;
+                }
+                response = writeMasterKey(pw);
+            }
+            if (response == NO_ERROR) {
+                setupMasterKeys();
+            }
+            return response;
+        }
+        if (mRetry <= 0) {
+            reset();
+            return UNINITIALIZED;
+        }
+        --mRetry;
+        switch (mRetry) {
+            case 0: return WRONG_PASSWORD_0;
+            case 1: return WRONG_PASSWORD_1;
+            case 2: return WRONG_PASSWORD_2;
+            case 3: return WRONG_PASSWORD_3;
+            default: return WRONG_PASSWORD_3;
+        }
+    }
+
+    bool reset() {
+        clearMasterKeys();
+        setState(STATE_UNINITIALIZED);
+
+        DIR* dir = opendir(".");
+        struct dirent* file;
+
+        if (!dir) {
+            return false;
+        }
+        while ((file = readdir(dir)) != NULL) {
+            if (isKeyFile(file->d_name)) {
+                unlink(file->d_name);
+            }
+        }
+        closedir(dir);
+        return true;
+    }
+
+    bool isEmpty() {
+        DIR* dir = opendir(".");
+        struct dirent* file;
+        if (!dir) {
+            return true;
+        }
+        bool result = true;
+        while ((file = readdir(dir)) != NULL) {
+            if (isKeyFile(file->d_name)) {
+                result = false;
+                break;
+            }
+        }
+        closedir(dir);
+        return result;
+    }
+
+    void lock() {
+        clearMasterKeys();
+        setState(STATE_LOCKED);
+    }
+
+    ResponseCode get(const char* filename, Blob* keyBlob) {
+        return keyBlob->decryptBlob(filename, &mMasterKeyDecryption);
+    }
+
+    ResponseCode put(const char* filename, Blob* keyBlob) {
+        return keyBlob->encryptBlob(filename, &mMasterKeyEncryption, mEntropy);
+    }
+
+private:
+    static const char* MASTER_KEY_FILE;
+    static const int MASTER_KEY_SIZE_BYTES = 16;
+    static const int MASTER_KEY_SIZE_BITS = MASTER_KEY_SIZE_BYTES * 8;
+
+    static const int MAX_RETRY = 4;
+    static const size_t SALT_SIZE = 16;
+
+    Entropy* mEntropy;
+
+    State mState;
+    int8_t mRetry;
+
+    uint8_t mMasterKey[MASTER_KEY_SIZE_BYTES];
+    uint8_t mSalt[SALT_SIZE];
+
+    AES_KEY mMasterKeyEncryption;
+    AES_KEY mMasterKeyDecryption;
+
+    void setState(State state) {
+        mState = state;
+        if (mState == STATE_NO_ERROR || mState == STATE_UNINITIALIZED) {
+            mRetry = MAX_RETRY;
+        }
+    }
+
+    bool generateSalt() {
+        return mEntropy->generate_random_data(mSalt, sizeof(mSalt));
+    }
+
+    bool generateMasterKey() {
+        if (!mEntropy->generate_random_data(mMasterKey, sizeof(mMasterKey))) {
+            return false;
+        }
+        if (!generateSalt()) {
+            return false;
+        }
+        return true;
+    }
+
+    void setupMasterKeys() {
+        AES_set_encrypt_key(mMasterKey, MASTER_KEY_SIZE_BITS, &mMasterKeyEncryption);
+        AES_set_decrypt_key(mMasterKey, MASTER_KEY_SIZE_BITS, &mMasterKeyDecryption);
+        setState(STATE_NO_ERROR);
+    }
+
+    void clearMasterKeys() {
+        memset(mMasterKey, 0, sizeof(mMasterKey));
+        memset(mSalt, 0, sizeof(mSalt));
+        memset(&mMasterKeyEncryption, 0, sizeof(mMasterKeyEncryption));
+        memset(&mMasterKeyDecryption, 0, sizeof(mMasterKeyDecryption));
+    }
+
+    static void generateKeyFromPassword(uint8_t* key, ssize_t keySize, Value* pw, uint8_t* salt) {
+        size_t saltSize;
+        if (salt != NULL) {
+            saltSize = SALT_SIZE;
+        } else {
+            // pre-gingerbread used this hardwired salt, readMasterKey will rewrite these when found
+            salt = (uint8_t*) "keystore";
+            // sizeof = 9, not strlen = 8
+            saltSize = sizeof("keystore");
+        }
+        PKCS5_PBKDF2_HMAC_SHA1((char*) pw->value, pw->length, salt, saltSize, 8192, keySize, key);
+    }
+
+    static bool isKeyFile(const char* filename) {
+        return ((strcmp(filename, MASTER_KEY_FILE) != 0)
+                && (strcmp(filename, ".") != 0)
+                && (strcmp(filename, "..") != 0));
+    }
+};
+
+const char* KeyStore::MASTER_KEY_FILE = ".masterkey";
+
+/* Here is the protocol used in both requests and responses:
+ *     code [length_1 message_1 ... length_n message_n] end-of-file
+ * where code is one byte long and lengths are unsigned 16-bit integers in
+ * network order. Thus the maximum length of a message is 65535 bytes. */
+
+static int recv_code(int sock, int8_t* code) {
+    return recv(sock, code, 1, 0) == 1;
+}
+
+static int recv_message(int sock, uint8_t* message, int length) {
+    uint8_t bytes[2];
+    if (recv(sock, &bytes[0], 1, 0) != 1 ||
+        recv(sock, &bytes[1], 1, 0) != 1) {
+        return -1;
+    } else {
+        int offset = bytes[0] << 8 | bytes[1];
+        if (length < offset) {
+            return -1;
+        }
+        length = offset;
+        offset = 0;
+        while (offset < length) {
+            int n = recv(sock, &message[offset], length - offset, 0);
+            if (n <= 0) {
+                return -1;
+            }
+            offset += n;
+        }
+    }
+    return length;
+}
+
+static int recv_end_of_file(int sock) {
+    uint8_t byte;
+    return recv(sock, &byte, 1, 0) == 0;
+}
+
+static void send_code(int sock, int8_t code) {
+    send(sock, &code, 1, 0);
+}
+
+static void send_message(int sock, uint8_t* message, int length) {
+    uint16_t bytes = htons(length);
+    send(sock, &bytes, 2, 0);
+    send(sock, message, length, 0);
+}
+
+/* Here are the actions. Each of them is a function without arguments. All
+ * information is defined in global variables, which are set properly before
+ * performing an action. The number of parameters required by each action is
+ * fixed and defined in a table. If the return value of an action is positive,
+ * it will be treated as a response code and transmitted to the client. Note
+ * that the lengths of parameters are checked when they are received, so
+ * boundary checks on parameters are omitted. */
+
+static const ResponseCode NO_ERROR_RESPONSE_CODE_SENT = (ResponseCode) 0;
+
+static ResponseCode test(KeyStore* keyStore, int sock, uid_t uid, Value*, Value*) {
+    return (ResponseCode) keyStore->getState();
+}
+
+static ResponseCode get(KeyStore* keyStore, int sock, uid_t uid, Value* keyName, Value*) {
+    char filename[NAME_MAX];
+    encode_key(filename, uid, keyName);
+    Blob keyBlob;
+    ResponseCode responseCode = keyStore->get(filename, &keyBlob);
+    if (responseCode != NO_ERROR) {
+        return responseCode;
+    }
+    send_code(sock, NO_ERROR);
+    send_message(sock, keyBlob.getValue(), keyBlob.getLength());
+    return NO_ERROR_RESPONSE_CODE_SENT;
+}
+
+static ResponseCode insert(KeyStore* keyStore, int sock, uid_t uid, Value* keyName, Value* val) {
+    char filename[NAME_MAX];
+    encode_key(filename, uid, keyName);
+    Blob keyBlob(val->value, val->length, 0, NULL);
+    return keyStore->put(filename, &keyBlob);
+}
+
+static ResponseCode del(KeyStore* keyStore, int sock, uid_t uid, Value* keyName, Value*) {
+    char filename[NAME_MAX];
+    encode_key(filename, uid, keyName);
+    return (unlink(filename) && errno != ENOENT) ? SYSTEM_ERROR : NO_ERROR;
+}
+
+static ResponseCode exist(KeyStore* keyStore, int sock, uid_t uid, Value* keyName, Value*) {
+    char filename[NAME_MAX];
+    encode_key(filename, uid, keyName);
+    if (access(filename, R_OK) == -1) {
+        return (errno != ENOENT) ? SYSTEM_ERROR : KEY_NOT_FOUND;
+    }
+    return NO_ERROR;
+}
+
+static ResponseCode saw(KeyStore* keyStore, int sock, uid_t uid, Value* keyPrefix, Value*) {
+    DIR* dir = opendir(".");
+    if (!dir) {
+        return SYSTEM_ERROR;
+    }
+    char filename[NAME_MAX];
+    int n = encode_key(filename, uid, keyPrefix);
+    send_code(sock, NO_ERROR);
+
+    struct dirent* file;
+    while ((file = readdir(dir)) != NULL) {
+        if (!strncmp(filename, file->d_name, n)) {
+            char* p = &file->d_name[n];
+            keyPrefix->length = decode_key(keyPrefix->value, p, strlen(p));
+            send_message(sock, keyPrefix->value, keyPrefix->length);
+        }
+    }
+    closedir(dir);
+    return NO_ERROR_RESPONSE_CODE_SENT;
+}
+
+static ResponseCode reset(KeyStore* keyStore, int sock, uid_t uid, Value*, Value*) {
+    return keyStore->reset() ? NO_ERROR : SYSTEM_ERROR;
+}
+
+/* Here is the history. To improve the security, the parameters to generate the
+ * master key has been changed. To make a seamless transition, we update the
+ * file using the same password when the user unlock it for the first time. If
+ * any thing goes wrong during the transition, the new file will not overwrite
+ * the old one. This avoids permanent damages of the existing data. */
+
+static ResponseCode password(KeyStore* keyStore, int sock, uid_t uid, Value* pw, Value*) {
+    switch (keyStore->getState()) {
+        case STATE_UNINITIALIZED: {
+            // generate master key, encrypt with password, write to file, initialize mMasterKey*.
+            return keyStore->initialize(pw);
+        }
+        case STATE_NO_ERROR: {
+            // rewrite master key with new password.
+            return keyStore->writeMasterKey(pw);
+        }
+        case STATE_LOCKED: {
+            // read master key, decrypt with password, initialize mMasterKey*.
+            return keyStore->readMasterKey(pw);
+        }
+    }
+    return SYSTEM_ERROR;
+}
+
+static ResponseCode lock(KeyStore* keyStore, int sock, uid_t uid, Value*, Value*) {
+    keyStore->lock();
+    return NO_ERROR;
+}
+
+static ResponseCode unlock(KeyStore* keyStore, int sock, uid_t uid, Value* pw, Value* unused) {
+    return password(keyStore, sock, uid, pw, unused);
+}
+
+static ResponseCode zero(KeyStore* keyStore, int sock, uid_t uid, Value*, Value*) {
+    return keyStore->isEmpty() ? KEY_NOT_FOUND : NO_ERROR;
+}
+
+/* Here are the permissions, actions, users, and the main function. */
+
+enum perm {
+    TEST     =    1,
+    GET      =    2,
+    INSERT   =    4,
+    DELETE   =    8,
+    EXIST    =   16,
+    SAW      =   32,
+    RESET    =   64,
+    PASSWORD =  128,
+    LOCK     =  256,
+    UNLOCK   =  512,
+    ZERO     = 1024,
+};
+
+static const int MAX_PARAM = 2;
+
+static const State STATE_ANY = (State) 0;
+
+static struct action {
+    ResponseCode (*run)(KeyStore* keyStore, int sock, uid_t uid, Value* param1, Value* param2);
+    int8_t code;
+    State state;
+    uint32_t perm;
+    int lengths[MAX_PARAM];
+} actions[] = {
+    {test,     't', STATE_ANY,      TEST,     {0, 0}},
+    {get,      'g', STATE_NO_ERROR, GET,      {KEY_SIZE, 0}},
+    {insert,   'i', STATE_NO_ERROR, INSERT,   {KEY_SIZE, VALUE_SIZE}},
+    {del,      'd', STATE_ANY,      DELETE,   {KEY_SIZE, 0}},
+    {exist,    'e', STATE_ANY,      EXIST,    {KEY_SIZE, 0}},
+    {saw,      's', STATE_ANY,      SAW,      {KEY_SIZE, 0}},
+    {reset,    'r', STATE_ANY,      RESET,    {0, 0}},
+    {password, 'p', STATE_ANY,      PASSWORD, {PASSWORD_SIZE, 0}},
+    {lock,     'l', STATE_NO_ERROR, LOCK,     {0, 0}},
+    {unlock,   'u', STATE_LOCKED,   UNLOCK,   {PASSWORD_SIZE, 0}},
+    {zero,     'z', STATE_ANY,      ZERO,     {0, 0}},
+    {NULL,      0 , STATE_ANY,      0,        {0, 0}},
+};
+
+static struct user {
+    uid_t uid;
+    uid_t euid;
+    uint32_t perms;
+} users[] = {
+    {AID_SYSTEM,   ~0,         ~GET},
+    {AID_VPN,      AID_SYSTEM, GET},
+    {AID_WIFI,     AID_SYSTEM, GET},
+    {AID_ROOT,     AID_SYSTEM, GET},
+    {AID_KEYCHAIN, AID_SYSTEM, TEST | GET | SAW},
+    {~0,           ~0,         TEST | GET | INSERT | DELETE | EXIST | SAW},
+};
+
+static ResponseCode process(KeyStore* keyStore, int sock, uid_t uid, int8_t code) {
+    struct user* user = users;
+    struct action* action = actions;
+    int i;
+
+    while (~user->uid && user->uid != uid) {
+        ++user;
+    }
+    while (action->code && action->code != code) {
+        ++action;
+    }
+    if (!action->code) {
+        return UNDEFINED_ACTION;
+    }
+    if (!(action->perm & user->perms)) {
+        return PERMISSION_DENIED;
+    }
+    if (action->state != STATE_ANY && action->state != keyStore->getState()) {
+        return (ResponseCode) keyStore->getState();
+    }
+    if (~user->euid) {
+        uid = user->euid;
+    }
+    Value params[MAX_PARAM];
+    for (i = 0; i < MAX_PARAM && action->lengths[i] != 0; ++i) {
+        params[i].length = recv_message(sock, params[i].value, action->lengths[i]);
+        if (params[i].length < 0) {
+            return PROTOCOL_ERROR;
+        }
+    }
+    if (!recv_end_of_file(sock)) {
+        return PROTOCOL_ERROR;
+    }
+    return action->run(keyStore, sock, uid, &params[0], &params[1]);
+}
+
+int main(int argc, char* argv[]) {
+    int controlSocket = android_get_control_socket("keystore");
+    if (argc < 2) {
+        LOGE("A directory must be specified!");
+        return 1;
+    }
+    if (chdir(argv[1]) == -1) {
+        LOGE("chdir: %s: %s", argv[1], strerror(errno));
+        return 1;
+    }
+
+    Entropy entropy;
+    if (!entropy.open()) {
+        return 1;
+    }
+    if (listen(controlSocket, 3) == -1) {
+        LOGE("listen: %s", strerror(errno));
+        return 1;
+    }
+
+    signal(SIGPIPE, SIG_IGN);
+
+    KeyStore keyStore(&entropy);
+    int sock;
+    while ((sock = accept(controlSocket, NULL, 0)) != -1) {
+        struct timeval tv;
+        tv.tv_sec = 3;
+        setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
+        setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
+
+        struct ucred cred;
+        socklen_t size = sizeof(cred);
+        int credResult = getsockopt(sock, SOL_SOCKET, SO_PEERCRED, &cred, &size);
+        if (credResult != 0) {
+            LOGW("getsockopt: %s", strerror(errno));
+        } else {
+            int8_t request;
+            if (recv_code(sock, &request)) {
+                State old_state = keyStore.getState();
+                ResponseCode response = process(&keyStore, sock, cred.uid, request);
+                if (response == NO_ERROR_RESPONSE_CODE_SENT) {
+                    response = NO_ERROR;
+                } else {
+                    send_code(sock, response);
+                }
+                LOGI("uid: %d action: %c -> %d state: %d -> %d retry: %d",
+                     cred.uid,
+                     request, response,
+                     old_state, keyStore.getState(),
+                     keyStore.getRetry());
+            }
+        }
+        close(sock);
+    }
+    LOGE("accept: %s", strerror(errno));
+    return 1;
+}
diff --git a/cmds/keystore/keystore.h b/cmds/keystore/keystore.h
index 5ef51e9..5ae3d24 100644
--- a/cmds/keystore/keystore.h
+++ b/cmds/keystore/keystore.h
@@ -17,17 +17,27 @@
 #ifndef __KEYSTORE_H__
 #define __KEYSTORE_H__
 
-enum response_code {
-    NO_ERROR          =  1,
-    LOCKED            =  2,
-    UNINITIALIZED     =  3,
+// note state values overlap with ResponseCode for the purposes of the state() API
+enum State {
+    STATE_NO_ERROR      = 1,
+    STATE_LOCKED        = 2,
+    STATE_UNINITIALIZED = 3,
+};
+
+enum ResponseCode {
+    NO_ERROR          =  STATE_NO_ERROR, // 1
+    LOCKED            =  STATE_LOCKED, // 2
+    UNINITIALIZED     =  STATE_UNINITIALIZED, // 3
     SYSTEM_ERROR      =  4,
     PROTOCOL_ERROR    =  5,
     PERMISSION_DENIED =  6,
     KEY_NOT_FOUND     =  7,
     VALUE_CORRUPTED   =  8,
     UNDEFINED_ACTION  =  9,
-    WRONG_PASSWORD    = 10,
+    WRONG_PASSWORD_0  = 10,
+    WRONG_PASSWORD_1  = 11,
+    WRONG_PASSWORD_2  = 12,
+    WRONG_PASSWORD_3  = 13, // MAX_RETRY = 4
 };
 
 #endif
diff --git a/cmds/keystore/keystore_cli.c b/cmds/keystore/keystore_cli.cpp
similarity index 67%
rename from cmds/keystore/keystore_cli.c
rename to cmds/keystore/keystore_cli.cpp
index e8afb5a..dcd3bcb 100644
--- a/cmds/keystore/keystore_cli.c
+++ b/cmds/keystore/keystore_cli.cpp
@@ -24,44 +24,40 @@
 
 #include "keystore.h"
 
-char *responses[256] = {
-    [NO_ERROR]           = "No error",
-    [LOCKED]             = "Locked",
-    [UNINITIALIZED]      = "Uninitialized",
-    [SYSTEM_ERROR]       = "System error",
-    [PROTOCOL_ERROR]     = "Protocol error",
-    [PERMISSION_DENIED]  = "Permission denied",
-    [KEY_NOT_FOUND]      = "Key not found",
-    [VALUE_CORRUPTED]    = "Value corrupted",
-    [UNDEFINED_ACTION]   = "Undefined action",
-    [WRONG_PASSWORD]     = "Wrong password (last chance)",
-    [WRONG_PASSWORD + 1] = "Wrong password (2 tries left)",
-    [WRONG_PASSWORD + 2] = "Wrong password (3 tries left)",
-    [WRONG_PASSWORD + 3] = "Wrong password (4 tries left)",
+static const char* responses[] = {
+    NULL,
+    /* [NO_ERROR]           = */ "No error",
+    /* [LOCKED]             = */ "Locked",
+    /* [UNINITIALIZED]      = */ "Uninitialized",
+    /* [SYSTEM_ERROR]       = */ "System error",
+    /* [PROTOCOL_ERROR]     = */ "Protocol error",
+    /* [PERMISSION_DENIED]  = */ "Permission denied",
+    /* [KEY_NOT_FOUND]      = */ "Key not found",
+    /* [VALUE_CORRUPTED]    = */ "Value corrupted",
+    /* [UNDEFINED_ACTION]   = */ "Undefined action",
+    /* [WRONG_PASSWORD]     = */ "Wrong password (last chance)",
+    /* [WRONG_PASSWORD + 1] = */ "Wrong password (2 tries left)",
+    /* [WRONG_PASSWORD + 2] = */ "Wrong password (3 tries left)",
+    /* [WRONG_PASSWORD + 3] = */ "Wrong password (4 tries left)",
 };
 
-#define MAX_RESPONSE (WRONG_PASSWORD + 3)
-
-int main(int argc, char **argv)
+int main(int argc, char* argv[])
 {
-    uint8_t bytes[65536];
-    uint8_t code;
-    int sock, i;
-
     if (argc < 2) {
         printf("Usage: %s action [parameter ...]\n", argv[0]);
         return 0;
     }
 
-    sock = socket_local_client("keystore", ANDROID_SOCKET_NAMESPACE_RESERVED,
-                               SOCK_STREAM);
+    int sock = socket_local_client("keystore", ANDROID_SOCKET_NAMESPACE_RESERVED,
+                                   SOCK_STREAM);
     if (sock == -1) {
         puts("Failed to connect");
         return 1;
     }
 
     send(sock, argv[1], 1, 0);
-    for (i = 2; i < argc; ++i) {
+    uint8_t bytes[65536];
+    for (int i = 2; i < argc; ++i) {
         uint16_t length = strlen(argv[i]);
         bytes[0] = length >> 8;
         bytes[1] = length;
@@ -70,11 +66,13 @@
     }
     shutdown(sock, SHUT_WR);
 
+    uint8_t code;
     if (recv(sock, &code, 1, 0) != 1) {
         puts("Failed to receive");
         return 1;
     }
     printf("%d %s\n", code , responses[code] ? responses[code] : "Unknown");
+    int i;
     while ((i = recv(sock, &bytes[0], 1, 0)) == 1) {
         int length;
         int offset;
diff --git a/libs/utils/BackupHelpers.cpp b/libs/utils/BackupHelpers.cpp
index e15875f..f933199 100644
--- a/libs/utils/BackupHelpers.cpp
+++ b/libs/utils/BackupHelpers.cpp
@@ -503,6 +503,16 @@
         needExtended = true;
     }
 
+    // Non-7bit-clean path also means needing pax extended format
+    if (!needExtended) {
+        for (size_t i = 0; i < filepath.length(); i++) {
+            if ((filepath[i] & 0x80) != 0) {
+                needExtended = true;
+                break;
+            }
+        }
+    }
+
     int err = 0;
     struct stat64 s;
     if (lstat64(filepath.string(), &s) != 0) {