diff --git a/cmds/installd/Android.mk b/cmds/installd/Android.mk
index 209632e..65bcf39 100644
--- a/cmds/installd/Android.mk
+++ b/cmds/installd/Android.mk
@@ -43,6 +43,43 @@
 LOCAL_CLANG := true
 include $(BUILD_EXECUTABLE)
 
+#
+# OTA Executable
+#
+
+include $(CLEAR_VARS)
+LOCAL_MODULE := otapreopt
+LOCAL_MODULE_TAGS := optional
+LOCAL_CFLAGS := $(common_cflags)
+
+# Base & ASLR boundaries for boot image creation.
+ifndef LIBART_IMG_HOST_MIN_BASE_ADDRESS_DELTA
+  LOCAL_LIBART_IMG_HOST_MIN_BASE_ADDRESS_DELTA := -0x1000000
+else
+  LOCAL_LIBART_IMG_HOST_MIN_BASE_ADDRESS_DELTA := $(LIBART_IMG_HOST_MIN_BASE_ADDRESS_DELTA)
+endif
+ifndef LIBART_IMG_HOST_MAX_BASE_ADDRESS_DELTA
+  LOCAL_LIBART_IMG_HOST_MAX_BASE_ADDRESS_DELTA := 0x1000000
+else
+  LOCAL_LIBART_IMG_HOST_MAX_BASE_ADDRESS_DELTA := $(LIBART_IMG_HOST_MAX_BASE_ADDRESS_DELTA)
+endif
+LOCAL_CFLAGS += -DART_BASE_ADDRESS=$(LIBART_IMG_HOST_BASE_ADDRESS)
+LOCAL_CFLAGS += -DART_BASE_ADDRESS_MIN_DELTA=$(LOCAL_LIBART_IMG_HOST_MIN_BASE_ADDRESS_DELTA)
+LOCAL_CFLAGS += -DART_BASE_ADDRESS_MAX_DELTA=$(LOCAL_LIBART_IMG_HOST_MAX_BASE_ADDRESS_DELTA)
+
+LOCAL_SRC_FILES := otapreopt.cpp $(common_src_files)
+LOCAL_SHARED_LIBRARIES := \
+    libbase \
+    libcutils \
+    liblog \
+    liblogwrap \
+    libselinux \
+
+LOCAL_STATIC_LIBRARIES := libdiskusage
+LOCAL_ADDITIONAL_DEPENDENCIES += $(LOCAL_PATH)/Android.mk
+LOCAL_CLANG := true
+include $(BUILD_EXECUTABLE)
+
 # Tests.
 
 include $(LOCAL_PATH)/tests/Android.mk
\ No newline at end of file
diff --git a/cmds/installd/installd.cpp b/cmds/installd/installd.cpp
index 02e9601..c0ae5b7 100644
--- a/cmds/installd/installd.cpp
+++ b/cmds/installd/installd.cpp
@@ -211,12 +211,41 @@
     return destroy_app_data(parse_null(arg[0]), arg[1], atoi(arg[2]), atoi(arg[3]));
 }
 
-static int do_dexopt(char **arg, char reply[REPLY_MAX] ATTRIBUTE_UNUSED)
+static int do_ota_dexopt(char **arg, char reply[REPLY_MAX] ATTRIBUTE_UNUSED) {
+  // Time to fork and run otapreopt.
+  pid_t pid = fork();
+  if (pid == 0) {
+    const char* argv[1 + 9 + 1];
+    argv[0] = "/system/bin/otapreopt";
+    for (size_t i = 1; i <= 9; ++i) {
+      argv[i] = arg[i - 1];
+    }
+    argv[10] = nullptr;
+
+    execv(argv[0], (char * const *)argv);
+    ALOGE("execv(OTAPREOPT) failed: %s\n", strerror(errno));
+    exit(99);
+  } else {
+    int res = wait_child(pid);
+    if (res == 0) {
+      ALOGV("DexInv: --- END OTAPREOPT (success) ---\n");
+    } else {
+      ALOGE("DexInv: --- END OTAPREOPT --- status=0x%04x, process failed\n", res);
+    }
+    return res;
+  }
+}
+
+static int do_dexopt(char **arg, char reply[REPLY_MAX])
 {
+    int dexopt_flags = atoi(arg[6]);
+    if ((dexopt_flags & DEXOPT_OTA) != 0) {
+      return do_ota_dexopt(arg, reply);
+    }
     /* apk_path, uid, pkgname, instruction_set, dexopt_needed, oat_dir, dexopt_flags, volume_uuid,
             use_profiles */
     return dexopt(arg[0], atoi(arg[1]), arg[2], arg[3], atoi(arg[4]),
-                  arg[5], atoi(arg[6]), parse_null(arg[7]), (atoi(arg[8]) == 0 ? false : true));
+                  arg[5], dexopt_flags, parse_null(arg[7]), (atoi(arg[8]) == 0 ? false : true));
 }
 
 static int do_mark_boot_complete(char **arg, char reply[REPLY_MAX] ATTRIBUTE_UNUSED)
diff --git a/cmds/installd/installd_constants.h b/cmds/installd/installd_constants.h
index 18f998d..0d21519 100644
--- a/cmds/installd/installd_constants.h
+++ b/cmds/installd/installd_constants.h
@@ -48,6 +48,7 @@
 // This is used as a string literal, can't be constants. TODO: std::string...
 #define DALVIK_CACHE "dalvik-cache"
 constexpr const char* DALVIK_CACHE_POSTFIX = "/classes.dex";
+constexpr const char* DALVIK_CACHE_POSTFIX2 = "@classes.dex";
 
 constexpr const char* IDMAP_PREFIX = "/data/resource-cache/";
 constexpr const char* IDMAP_SUFFIX = "@idmap";
@@ -74,6 +75,7 @@
 constexpr int DEXOPT_DEBUGGABLE   = 1 << 3;
 constexpr int DEXOPT_BOOTCOMPLETE = 1 << 4;
 constexpr int DEXOPT_EXTRACTONLY  = 1 << 5;
+constexpr int DEXOPT_OTA          = 1 << 6;
 
 /* all known values for dexopt flags */
 constexpr int DEXOPT_MASK =
@@ -81,7 +83,8 @@
     | DEXOPT_SAFEMODE
     | DEXOPT_DEBUGGABLE
     | DEXOPT_BOOTCOMPLETE
-    | DEXOPT_EXTRACTONLY;
+    | DEXOPT_EXTRACTONLY
+    | DEXOPT_OTA;
 
 #define ARRAY_SIZE(a) (sizeof(a) / sizeof(*(a)))
 
diff --git a/cmds/installd/otapreopt.cpp b/cmds/installd/otapreopt.cpp
new file mode 100644
index 0000000..27f7939
--- /dev/null
+++ b/cmds/installd/otapreopt.cpp
@@ -0,0 +1,641 @@
+/*
+ ** Copyright 2016, 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 <algorithm>
+#include <inttypes.h>
+#include <random>
+#include <selinux/android.h>
+#include <selinux/avc.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/capability.h>
+#include <sys/prctl.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+
+#include <android-base/logging.h>
+#include <android-base/macros.h>
+#include <android-base/stringprintf.h>
+#include <cutils/fs.h>
+#include <cutils/log.h>
+#include <cutils/properties.h>
+#include <private/android_filesystem_config.h>
+
+#include <commands.h>
+#include <globals.h>
+#include <installd_deps.h>  // Need to fill in requirements of commands.
+#include <string_helpers.h>
+#include <system_properties.h>
+#include <utils.h>
+
+#ifndef LOG_TAG
+#define LOG_TAG "otapreopt"
+#endif
+
+#define BUFFER_MAX    1024  /* input buffer for commands */
+#define TOKEN_MAX     16    /* max number of arguments in buffer */
+#define REPLY_MAX     256   /* largest reply allowed */
+
+using android::base::StringPrintf;
+
+namespace android {
+namespace installd {
+
+static constexpr const char* kBootClassPathPropertyName = "env.BOOTCLASSPATH";
+static constexpr const char* kAndroidRootPathPropertyName = "env.ANDROID_ROOT";
+static constexpr const char* kOTARootDirectory = "/system-b";
+static constexpr size_t kISAIndex = 3;
+
+template<typename T>
+static constexpr T RoundDown(T x, typename std::decay<T>::type n) {
+    return DCHECK_CONSTEXPR(IsPowerOfTwo(n), , T(0))(x & -n);
+}
+
+template<typename T>
+static constexpr T RoundUp(T x, typename std::remove_reference<T>::type n) {
+    return RoundDown(x + n - 1, n);
+}
+
+class OTAPreoptService {
+ public:
+    static constexpr const char* kOTADataDirectory = "/data/ota";
+
+    // Main driver. Performs the following steps.
+    //
+    // 1) Parse options (read system properties etc from B partition).
+    //
+    // 2) Read in package data.
+    //
+    // 3) Prepare environment variables.
+    //
+    // 4) Prepare(compile) boot image, if necessary.
+    //
+    // 5) Run update.
+    int Main(int argc, char** argv) {
+        if (!ReadSystemProperties()) {
+            LOG(ERROR)<< "Failed reading system properties.";
+            return 1;
+        }
+
+        if (!ReadEnvironment()) {
+            LOG(ERROR) << "Failed reading environment properties.";
+            return 2;
+        }
+
+        if (!ReadPackage(argc, argv)) {
+            LOG(ERROR) << "Failed reading command line file.";
+            return 3;
+        }
+
+        PrepareEnvironment();
+
+        if (!PrepareBootImage()) {
+            LOG(ERROR) << "Failed preparing boot image.";
+            return 4;
+        }
+
+        int dexopt_retcode = RunPreopt();
+
+        return dexopt_retcode;
+    }
+
+    int GetProperty(const char* key, char* value, const char* default_value) {
+        const std::string* prop_value = system_properties_.GetProperty(key);
+        if (prop_value == nullptr) {
+            if (default_value == nullptr) {
+                return 0;
+            }
+            // Copy in the default value.
+            strncpy(value, default_value, kPropertyValueMax - 1);
+            value[kPropertyValueMax - 1] = 0;
+            return strlen(default_value);// TODO: Need to truncate?
+        }
+        size_t size = std::min(kPropertyValueMax - 1, prop_value->length());
+        strncpy(value, prop_value->data(), size);
+        value[size] = 0;
+        return static_cast<int>(size);
+    }
+
+private:
+    bool ReadSystemProperties() {
+        // TODO(agampe): What to do about the things in default.prop? It's only heap sizes, so it's easy
+        //               to emulate for now, but has issues (e.g., vendors modifying the boot classpath
+        //               may require larger values here - revisit). That's why this goes first, so that
+        //               if those dummy values are overridden in build.prop, that's what we'll get.
+        //
+        // Note: It seems we'll get access to the B root partition, so we should read the default.prop
+        //       file.
+        // if (!system_properties_.Load(b_mount_path_ + "/default.prop") {
+        //   return false;
+        // }
+        system_properties_.SetProperty("dalvik.vm.image-dex2oat-Xms", "64m");
+        system_properties_.SetProperty("dalvik.vm.image-dex2oat-Xmx", "64m");
+        system_properties_.SetProperty("dalvik.vm.dex2oat-Xms", "64m");
+        system_properties_.SetProperty("dalvik.vm.dex2oat-Xmx", "512m");
+
+        // TODO(agampe): Do this properly/test.
+        return system_properties_.Load(b_mount_path_ + "/system/build.prop");
+    }
+
+    bool ReadEnvironment() {
+        // Read important environment variables. For simplicity, store them as
+        // system properties.
+        // TODO(agampe): We'll have to parse init.environ.rc for BOOTCLASSPATH.
+        //               For now, just the A version.
+        const char* boot_classpath = getenv("BOOTCLASSPATH");
+        if (boot_classpath == nullptr) {
+            return false;
+        }
+        system_properties_.SetProperty(kBootClassPathPropertyName, boot_classpath);
+
+        const char* root_path = getenv("ANDROID_ROOT");
+        if (root_path == nullptr) {
+            return false;
+        }
+        system_properties_.SetProperty(kAndroidRootPathPropertyName, b_mount_path_ + root_path);
+
+        return true;
+    }
+
+    bool ReadPackage(int argc ATTRIBUTE_UNUSED, char** argv) {
+        size_t index = 0;
+        while (index < ARRAY_SIZE(package_parameters_) &&
+                argv[index + 1] != nullptr) {
+            package_parameters_[index] = argv[index + 1];
+            index++;
+        }
+        if (index != ARRAY_SIZE(package_parameters_)) {
+            LOG(ERROR) << "Wrong number of parameters";
+            return false;
+        }
+
+        return true;
+    }
+
+    void PrepareEnvironment() {
+        CHECK(system_properties_.GetProperty(kBootClassPathPropertyName) != nullptr);
+        const std::string& boot_cp =
+                *system_properties_.GetProperty(kBootClassPathPropertyName);
+        environ_.push_back(StringPrintf("BOOTCLASSPATH=%s", boot_cp.c_str()));
+        environ_.push_back(StringPrintf("ANDROID_DATA=%s", kOTADataDirectory));
+        CHECK(system_properties_.GetProperty(kAndroidRootPathPropertyName) != nullptr);
+        const std::string& android_root =
+                *system_properties_.GetProperty(kAndroidRootPathPropertyName);
+        environ_.push_back(StringPrintf("ANDROID_ROOT=%s", android_root.c_str()));
+
+        for (const std::string& e : environ_) {
+            putenv(const_cast<char*>(e.c_str()));
+        }
+    }
+
+    // Ensure that we have the right boot image. The first time any app is
+    // compiled, we'll try to generate it.
+    bool PrepareBootImage() {
+        if (package_parameters_[kISAIndex] == nullptr) {
+            LOG(ERROR) << "Instruction set missing.";
+            return false;
+        }
+        const char* isa = package_parameters_[kISAIndex];
+
+        // Check whether the file exists where expected.
+        std::string dalvik_cache = std::string(kOTADataDirectory) + "/" + DALVIK_CACHE;
+        std::string isa_path = dalvik_cache + "/" + isa;
+        std::string art_path = isa_path + "/system@framework@boot.art";
+        std::string oat_path = isa_path + "/system@framework@boot.oat";
+        if (access(art_path.c_str(), F_OK) == 0 &&
+                access(oat_path.c_str(), F_OK) == 0) {
+            // Files exist, assume everything is alright.
+            return true;
+        }
+
+        // Create the directories, if necessary.
+        if (access(dalvik_cache.c_str(), F_OK) != 0) {
+            if (mkdir(dalvik_cache.c_str(), 0711) != 0) {
+                PLOG(ERROR) << "Could not create dalvik-cache dir";
+                return false;
+            }
+        }
+        if (access(isa_path.c_str(), F_OK) != 0) {
+            if (mkdir(isa_path.c_str(), 0711) != 0) {
+                PLOG(ERROR) << "Could not create dalvik-cache isa dir";
+                return false;
+            }
+        }
+
+        // Prepare and run dex2oat.
+        // TODO: Delete files, just for a blank slate.
+        const std::string& boot_cp = *system_properties_.GetProperty(kBootClassPathPropertyName);
+
+        // This needs to be kept in sync with ART, see art/runtime/gc/space/image_space.cc.
+        std::vector<std::string> cmd;
+        cmd.push_back(b_mount_path_ + "/system/bin/dex2oat");
+        cmd.push_back(StringPrintf("--image=%s", art_path.c_str()));
+        for (const std::string& boot_part : Split(boot_cp, ':')) {
+            cmd.push_back(StringPrintf("--dex-file=%s", boot_part.c_str()));
+        }
+        cmd.push_back(StringPrintf("--oat-file=%s", oat_path.c_str()));
+
+        int32_t base_offset = ChooseRelocationOffsetDelta(ART_BASE_ADDRESS_MIN_DELTA,
+                ART_BASE_ADDRESS_MAX_DELTA);
+        cmd.push_back(StringPrintf("--base=0x%x", ART_BASE_ADDRESS + base_offset));
+
+        cmd.push_back(StringPrintf("--instruction-set=%s", isa));
+
+        // These things are pushed by AndroidRuntime, see frameworks/base/core/jni/AndroidRuntime.cpp.
+        AddCompilerOptionFromSystemProperty("dalvik.vm.image-dex2oat-Xms",
+                "-Xms",
+                true,
+                cmd);
+        AddCompilerOptionFromSystemProperty("dalvik.vm.image-dex2oat-Xmx",
+                "-Xmx",
+                true,
+                cmd);
+        AddCompilerOptionFromSystemProperty("dalvik.vm.image-dex2oat-filter",
+                "--compiler-filter=",
+                false,
+                cmd);
+        cmd.push_back(StringPrintf("--image-classes=%s/system/etc/preloaded-classes",
+                                   b_mount_path_.c_str()));
+        // TODO: Compiled-classes.
+        const std::string* extra_opts =
+                system_properties_.GetProperty("dalvik.vm.image-dex2oat-flags");
+        if (extra_opts != nullptr) {
+            std::vector<std::string> extra_vals = Split(*extra_opts, ' ');
+            cmd.insert(cmd.end(), extra_vals.begin(), extra_vals.end());
+        }
+        // TODO: Should we lower this? It's usually set close to max, because
+        //       normally there's not much else going on at boot.
+        AddCompilerOptionFromSystemProperty("dalvik.vm.image-dex2oat-threads",
+                "-j",
+                false,
+                cmd);
+        AddCompilerOptionFromSystemProperty(
+                StringPrintf("dalvik.vm.isa.%s.variant", isa).c_str(),
+                "--instruction-set-variant=",
+                false,
+                cmd);
+        AddCompilerOptionFromSystemProperty(
+                StringPrintf("dalvik.vm.isa.%s.features", isa).c_str(),
+                "--instruction-set-features=",
+                false,
+                cmd);
+
+        std::string error_msg;
+        bool result = Exec(cmd, &error_msg);
+        if (!result) {
+            LOG(ERROR) << "Could not generate boot image: " << error_msg;
+        }
+        return result;
+    }
+
+    static const char* ParseNull(const char* arg) {
+        return (strcmp(arg, "!") == 0) ? nullptr : arg;
+    }
+
+    int RunPreopt() {
+        /* apk_path, uid, pkgname, instruction_set, dexopt_needed, oat_dir, dexopt_flags,
+           volume_uuid, use_profiles */
+        int ret = dexopt(package_parameters_[0],
+                atoi(package_parameters_[1]),
+                package_parameters_[2],
+                package_parameters_[3],
+                atoi(package_parameters_[4]),
+                package_parameters_[5],
+                atoi(package_parameters_[6]),
+                ParseNull(package_parameters_[7]),
+                (atoi(package_parameters_[8]) == 0 ? false : true));
+        return ret;
+    }
+
+    ////////////////////////////////////
+    // Helpers, mostly taken from ART //
+    ////////////////////////////////////
+
+    // Wrapper on fork/execv to run a command in a subprocess.
+    bool Exec(const std::vector<std::string>& arg_vector, std::string* error_msg) {
+        const std::string command_line(Join(arg_vector, ' '));
+
+        CHECK_GE(arg_vector.size(), 1U) << command_line;
+
+        // Convert the args to char pointers.
+        const char* program = arg_vector[0].c_str();
+        std::vector<char*> args;
+        for (size_t i = 0; i < arg_vector.size(); ++i) {
+            const std::string& arg = arg_vector[i];
+            char* arg_str = const_cast<char*>(arg.c_str());
+            CHECK(arg_str != nullptr) << i;
+            args.push_back(arg_str);
+        }
+        args.push_back(nullptr);
+
+        // Fork and exec.
+        pid_t pid = fork();
+        if (pid == 0) {
+            // No allocation allowed between fork and exec.
+
+            // Change process groups, so we don't get reaped by ProcessManager.
+            setpgid(0, 0);
+
+            execv(program, &args[0]);
+
+            PLOG(ERROR) << "Failed to execv(" << command_line << ")";
+            // _exit to avoid atexit handlers in child.
+            _exit(1);
+        } else {
+            if (pid == -1) {
+                *error_msg = StringPrintf("Failed to execv(%s) because fork failed: %s",
+                        command_line.c_str(), strerror(errno));
+                return false;
+            }
+
+            // wait for subprocess to finish
+            int status;
+            pid_t got_pid = TEMP_FAILURE_RETRY(waitpid(pid, &status, 0));
+            if (got_pid != pid) {
+                *error_msg = StringPrintf("Failed after fork for execv(%s) because waitpid failed: "
+                        "wanted %d, got %d: %s",
+                        command_line.c_str(), pid, got_pid, strerror(errno));
+                return false;
+            }
+            if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
+                *error_msg = StringPrintf("Failed execv(%s) because non-0 exit status",
+                        command_line.c_str());
+                return false;
+            }
+        }
+        return true;
+    }
+
+    // Choose a random relocation offset. Taken from art/runtime/gc/image_space.cc.
+    static int32_t ChooseRelocationOffsetDelta(int32_t min_delta, int32_t max_delta) {
+        constexpr size_t kPageSize = PAGE_SIZE;
+        CHECK_EQ(min_delta % kPageSize, 0u);
+        CHECK_EQ(max_delta % kPageSize, 0u);
+        CHECK_LT(min_delta, max_delta);
+
+        std::default_random_engine generator;
+        generator.seed(GetSeed());
+        std::uniform_int_distribution<int32_t> distribution(min_delta, max_delta);
+        int32_t r = distribution(generator);
+        if (r % 2 == 0) {
+            r = RoundUp(r, kPageSize);
+        } else {
+            r = RoundDown(r, kPageSize);
+        }
+        CHECK_LE(min_delta, r);
+        CHECK_GE(max_delta, r);
+        CHECK_EQ(r % kPageSize, 0u);
+        return r;
+    }
+
+    static uint64_t GetSeed() {
+#ifdef __BIONIC__
+        // Bionic exposes arc4random, use it.
+        uint64_t random_data;
+        arc4random_buf(&random_data, sizeof(random_data));
+        return random_data;
+#else
+#error "This is only supposed to run with bionic. Otherwise, implement..."
+#endif
+    }
+
+    void AddCompilerOptionFromSystemProperty(const char* system_property,
+            const char* prefix,
+            bool runtime,
+            std::vector<std::string>& out) {
+        const std::string* value =
+        system_properties_.GetProperty(system_property);
+        if (value != nullptr) {
+            if (runtime) {
+                out.push_back("--runtime-arg");
+            }
+            if (prefix != nullptr) {
+                out.push_back(StringPrintf("%s%s", prefix, value->c_str()));
+            } else {
+                out.push_back(*value);
+            }
+        }
+    }
+
+    // The path where the B partitions are mounted.
+    // TODO(agampe): If we're running this *inside* the change-root, we wouldn't need this.
+    std::string b_mount_path_;
+
+    // Stores the system properties read out of the B partition. We need to use these properties
+    // to compile, instead of the A properties we could get from init/get_property.
+    SystemProperties system_properties_;
+
+    const char* package_parameters_[9];
+
+    // Store environment values we need to set.
+    std::vector<std::string> environ_;
+};
+
+OTAPreoptService gOps;
+
+////////////////////////
+// Plug-in functions. //
+////////////////////////
+
+int get_property(const char *key, char *value, const char *default_value) {
+    // TODO: Replace with system-properties map.
+    return gOps.GetProperty(key, value, default_value);
+}
+
+// Compute the output path of
+bool calculate_oat_file_path(char path[PKG_PATH_MAX], const char *oat_dir,
+                             const char *apk_path,
+                             const char *instruction_set) {
+    // TODO: Insert B directory.
+    char *file_name_start;
+    char *file_name_end;
+
+    file_name_start = strrchr(apk_path, '/');
+    if (file_name_start == nullptr) {
+        ALOGE("apk_path '%s' has no '/'s in it\n", apk_path);
+        return false;
+    }
+    file_name_end = strrchr(file_name_start, '.');
+    if (file_name_end == nullptr) {
+        ALOGE("apk_path '%s' has no extension\n", apk_path);
+        return false;
+    }
+
+    // Calculate file_name
+    file_name_start++;  // Move past '/', is valid as file_name_end is valid.
+    size_t file_name_len = file_name_end - file_name_start;
+    std::string file_name(file_name_start, file_name_len);
+
+    // <apk_parent_dir>/oat/<isa>/<file_name>.odex.b
+    snprintf(path, PKG_PATH_MAX, "%s/%s/%s.odex.b", oat_dir, instruction_set,
+             file_name.c_str());
+    return true;
+}
+
+/*
+ * Computes the odex file for the given apk_path and instruction_set.
+ * /system/framework/whatever.jar -> /system/framework/oat/<isa>/whatever.odex
+ *
+ * Returns false if it failed to determine the odex file path.
+ */
+bool calculate_odex_file_path(char path[PKG_PATH_MAX], const char *apk_path,
+                              const char *instruction_set) {
+    if (StringPrintf("%soat/%s/odex.b", apk_path, instruction_set).length() + 1 > PKG_PATH_MAX) {
+        ALOGE("apk_path '%s' may be too long to form odex file path.\n", apk_path);
+        return false;
+    }
+
+    const char *path_end = strrchr(apk_path, '/');
+    if (path_end == nullptr) {
+        ALOGE("apk_path '%s' has no '/'s in it?!\n", apk_path);
+        return false;
+    }
+    std::string path_component(apk_path, path_end - apk_path);
+
+    const char *name_begin = path_end + 1;
+    const char *extension_start = strrchr(name_begin, '.');
+    if (extension_start == nullptr) {
+        ALOGE("apk_path '%s' has no extension.\n", apk_path);
+        return false;
+    }
+    std::string name_component(name_begin, extension_start - name_begin);
+
+    std::string new_path = StringPrintf("%s/oat/%s/%s.odex.b",
+                                        path_component.c_str(),
+                                        instruction_set,
+                                        name_component.c_str());
+    CHECK_LT(new_path.length(), PKG_PATH_MAX);
+    strcpy(path, new_path.c_str());
+    return true;
+}
+
+bool create_cache_path(char path[PKG_PATH_MAX],
+                       const char *src,
+                       const char *instruction_set) {
+    size_t srclen = strlen(src);
+
+        /* demand that we are an absolute path */
+    if ((src == 0) || (src[0] != '/') || strstr(src,"..")) {
+        return false;
+    }
+
+    if (srclen > PKG_PATH_MAX) {        // XXX: PKG_NAME_MAX?
+        return false;
+    }
+
+    std::string from_src = std::string(src + 1);
+    std::replace(from_src.begin(), from_src.end(), '/', '@');
+
+    std::string assembled_path = StringPrintf("%s/%s/%s/%s%s",
+                                              OTAPreoptService::kOTADataDirectory,
+                                              DALVIK_CACHE,
+                                              instruction_set,
+                                              from_src.c_str(),
+                                              DALVIK_CACHE_POSTFIX2);
+
+    if (assembled_path.length() + 1 > PKG_PATH_MAX) {
+        return false;
+    }
+    strcpy(path, assembled_path.c_str());
+
+    return true;
+}
+
+bool initialize_globals() {
+    const char* data_path = getenv("ANDROID_DATA");
+    if (data_path == nullptr) {
+        ALOGE("Could not find ANDROID_DATA");
+        return false;
+    }
+    return init_globals_from_data_and_root(data_path, kOTARootDirectory);
+}
+
+static bool initialize_directories() {
+    // This is different from the normal installd. We only do the base
+    // directory, the rest will be created on demand when each app is compiled.
+    mode_t old_umask = umask(0);
+    LOG(INFO) << "Old umask: " << old_umask;
+    if (access(OTAPreoptService::kOTADataDirectory, R_OK) < 0) {
+        ALOGE("Could not access %s\n", OTAPreoptService::kOTADataDirectory);
+        return false;
+    }
+    return true;
+}
+
+static int log_callback(int type, const char *fmt, ...) {
+    va_list ap;
+    int priority;
+
+    switch (type) {
+        case SELINUX_WARNING:
+            priority = ANDROID_LOG_WARN;
+            break;
+        case SELINUX_INFO:
+            priority = ANDROID_LOG_INFO;
+            break;
+        default:
+            priority = ANDROID_LOG_ERROR;
+            break;
+    }
+    va_start(ap, fmt);
+    LOG_PRI_VA(priority, "SELinux", fmt, ap);
+    va_end(ap);
+    return 0;
+}
+
+static int otapreopt_main(const int argc, char *argv[]) {
+    int selinux_enabled = (is_selinux_enabled() > 0);
+
+    setenv("ANDROID_LOG_TAGS", "*:v", 1);
+    android::base::InitLogging(argv);
+
+    ALOGI("otapreopt firing up\n");
+
+    if (argc < 2) {
+        ALOGE("Expecting parameters");
+        exit(1);
+    }
+
+    union selinux_callback cb;
+    cb.func_log = log_callback;
+    selinux_set_callback(SELINUX_CB_LOG, cb);
+
+    if (!initialize_globals()) {
+        ALOGE("Could not initialize globals; exiting.\n");
+        exit(1);
+    }
+
+    if (!initialize_directories()) {
+        ALOGE("Could not create directories; exiting.\n");
+        exit(1);
+    }
+
+    if (selinux_enabled && selinux_status_open(true) < 0) {
+        ALOGE("Could not open selinux status; exiting.\n");
+        exit(1);
+    }
+
+    int ret = android::installd::gOps.Main(argc, argv);
+
+    return ret;
+}
+
+}  // namespace installd
+}  // namespace android
+
+int main(const int argc, char *argv[]) {
+    return android::installd::otapreopt_main(argc, argv);
+}
diff --git a/cmds/installd/string_helpers.h b/cmds/installd/string_helpers.h
new file mode 100644
index 0000000..e8fcdef
--- /dev/null
+++ b/cmds/installd/string_helpers.h
@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#ifndef ART_OTAPREOPT_STRING_HELPERS_H_
+#define ART_OTAPREOPT_STRING_HELPERS_H_
+
+#include <sstream>
+#include <string>
+
+#include <android-base/macros.h>
+
+namespace android {
+namespace installd {
+
+static inline bool StringStartsWith(const std::string& target,
+                                    const char* prefix) {
+    return target.compare(0, strlen(prefix), prefix) == 0;
+}
+
+// Split the input according to the separator character. Doesn't honor quotation.
+static inline std::vector<std::string> Split(const std::string& in, const char separator) {
+    if (in.empty()) {
+        return std::vector<std::string>();
+    }
+
+    std::vector<std::string> ret;
+    std::stringstream strstr(in);
+    std::string token;
+
+    while (std::getline(strstr, token, separator)) {
+        ret.push_back(token);
+    }
+
+    return ret;
+}
+
+template <typename StringT>
+static inline std::string Join(const std::vector<StringT>& strings, char separator) {
+    if (strings.empty()) {
+        return "";
+    }
+
+    std::string result(strings[0]);
+    for (size_t i = 1; i < strings.size(); ++i) {
+        result += separator;
+        result += strings[i];
+    }
+    return result;
+}
+
+}  // namespace installd
+}  // namespace android
+
+#endif  // ART_OTAPREOPT_STRING_HELPERS_H_
diff --git a/cmds/installd/system_properties.h b/cmds/installd/system_properties.h
new file mode 100644
index 0000000..1b5fb3a
--- /dev/null
+++ b/cmds/installd/system_properties.h
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#ifndef OTAPREOPT_SYSTEM_PROPERTIES_H_
+#define OTAPREOPT_SYSTEM_PROPERTIES_H_
+
+#include <fstream>
+#include <string>
+#include <unordered_map>
+
+namespace android {
+namespace installd {
+
+// Helper class to read system properties into and manage as a string->string map.
+class SystemProperties {
+ public:
+    bool Load(const std::string& strFile) {
+        std::ifstream input_stream(strFile);
+
+        if (!input_stream.is_open()) {
+            return false;
+        }
+
+        while (!input_stream.eof()) {
+            // Read the next line.
+            std::string line;
+            getline(input_stream, line);
+
+            // Is the line empty? Simplifies the next check.
+            if (line.empty()) {
+                continue;
+            }
+
+            // Is this a comment (starts with pound)?
+            if (line[0] == '#') {
+                continue;
+            }
+
+            size_t equals_pos = line.find('=');
+            if (equals_pos == std::string::npos || equals_pos == 0) {
+                // Did not find equals sign, or it's the first character - isn't a valid line.
+                continue;
+            }
+
+            std::string key = line.substr(0, equals_pos);
+            std::string value = line.substr(equals_pos + 1,
+                                            line.length() - equals_pos + 1);
+
+            properties_.insert(std::make_pair(key, value));
+        }
+
+        return true;
+    }
+
+    // Look up the key in the map. Returns null if the key isn't mapped.
+    const std::string* GetProperty(const std::string& key) const {
+        auto it = properties_.find(key);
+        if (it != properties_.end()) {
+            return &it->second;
+        }
+        return nullptr;
+    }
+
+    void SetProperty(const std::string& key, const std::string& value) {
+        properties_.insert(std::make_pair(key, value));
+    }
+
+ private:
+    // The actual map.
+    std::unordered_map<std::string, std::string> properties_;
+};
+
+}  // namespace installd
+}  // namespace android
+
+#endif  // OTAPREOPT_SYSTEM_PROPERTIES_H_