Merge changes I09b11db0,I774b1a44

* changes:
  libcutils: add file permission for storaged
  storaged: add storaged native daemon
diff --git a/libcutils/fs_config.c b/libcutils/fs_config.c
index 99f97d1..a99810b 100644
--- a/libcutils/fs_config.c
+++ b/libcutils/fs_config.c
@@ -149,6 +149,10 @@
                                               "system/bin/run-as" },
     { 00700, AID_SYSTEM,    AID_SHELL,     CAP_MASK_LONG(CAP_BLOCK_SUSPEND),
                                               "system/bin/inputflinger" },
+    { 00750, AID_SYSTEM,    AID_SHELL,     CAP_MASK_LONG(CAP_SETUID) |
+                                           CAP_MASK_LONG(CAP_SETGID) |
+                                           CAP_MASK_LONG(CAP_SYS_PTRACE),
+                                              "system/bin/storaged" },
 
     /* Support FIFO scheduling mode in SurfaceFlinger. */
     { 00755, AID_SYSTEM,    AID_GRAPHICS,  CAP_MASK_LONG(CAP_SYS_NICE),
diff --git a/storaged/Android.mk b/storaged/Android.mk
new file mode 100644
index 0000000..db97040
--- /dev/null
+++ b/storaged/Android.mk
@@ -0,0 +1,34 @@
+# Copyright 2016 The Android Open Source Project
+
+LOCAL_PATH := $(call my-dir)
+
+LIBSTORAGED_SHARED_LIBRARIES := libbinder libbase libutils libcutils liblog libsysutils libcap
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := storaged.cpp \
+                  storaged_service.cpp \
+                  storaged_utils.cpp \
+                  EventLogTags.logtags
+LOCAL_MODULE := libstoraged
+LOCAL_CFLAGS := -Werror
+LOCAL_C_INCLUDES := $(LOCAL_PATH)/include external/googletest/googletest/include
+LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)/include
+LOCAL_SHARED_LIBRARIES := $(LIBSTORAGED_SHARED_LIBRARIES)
+
+include $(BUILD_STATIC_LIBRARY)
+
+include $(CLEAR_VARS)
+
+LOCAL_MODULE := storaged
+LOCAL_INIT_RC := storaged.rc
+LOCAL_SRC_FILES := main.cpp
+# libstoraged is an internal static library, only main.cpp and storaged_test.cpp should be using it
+LOCAL_STATIC_LIBRARIES := libstoraged
+LOCAL_SHARED_LIBRARIES := $(LIBSTORAGED_SHARED_LIBRARIES)
+LOCAL_CFLAGS := -Wall -Werror -Wno-unused-parameter
+LOCAL_C_INCLUDES := external/googletest/googletest/include
+
+include $(BUILD_EXECUTABLE)
+
+include $(call first-makefiles-under,$(LOCAL_PATH))
diff --git a/storaged/EventLogTags.logtags b/storaged/EventLogTags.logtags
new file mode 100644
index 0000000..2e25d4a
--- /dev/null
+++ b/storaged/EventLogTags.logtags
@@ -0,0 +1,39 @@
+# The entries in this file map a sparse set of log tag numbers to tag names.
+# This is installed on the device, in /system/etc, and parsed by logcat.
+#
+# Tag numbers are decimal integers, from 0 to 2^31.  (Let's leave the
+# negative values alone for now.)
+#
+# Tag names are one or more ASCII letters and numbers or underscores, i.e.
+# "[A-Z][a-z][0-9]_".  Do not include spaces or punctuation (the former
+# impacts log readability, the latter makes regex searches more annoying).
+#
+# Tag numbers and names are separated by whitespace.  Blank lines and lines
+# starting with '#' are ignored.
+#
+# Optionally, after the tag names can be put a description for the value(s)
+# of the tag. Description are in the format
+#    (<name>|data type[|data unit])
+# Multiple values are separated by commas.
+#
+# The data type is a number from the following values:
+# 1: int
+# 2: long
+# 3: string
+# 4: list
+# 5: float
+#
+# The data unit is a number taken from the following list:
+# 1: Number of objects
+# 2: Number of bytes
+# 3: Number of milliseconds
+# 4: Number of allocations
+# 5: Id
+# 6: Percent
+# Default value for data of type int/long is 2 (bytes).
+#
+# TODO: generate ".java" and ".h" files with integer constants from this file.
+
+2732 storaged_disk_stats (type|3),(start_time|2|3),(end_time|2|3),(read_ios|2|1),(read_merges|2|1),(read_sectors|2|1),(read_ticks|2|3),(write_ios|2|1),(write_merges|2|1),(write_sectors|2|1),(write_ticks|2|3),(o_in_flight|2|1),(io_ticks|2|3),(io_in_queue|2|1)
+
+2733 storaged_emmc_info (mmc_ver|3),(eol|1),(lifetime_a|1),(lifetime_b|1)
\ No newline at end of file
diff --git a/storaged/include/storaged.h b/storaged/include/storaged.h
new file mode 100644
index 0000000..eb827cf
--- /dev/null
+++ b/storaged/include/storaged.h
@@ -0,0 +1,340 @@
+/*
+ * Copyright (C) 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.
+ */
+
+#ifndef _STORAGED_H_
+#define _STORAGED_H_
+
+#define DEBUG
+
+#include <queue>
+#include <semaphore.h>
+#include <stdint.h>
+#include <string>
+#include <syslog.h>
+#include <unordered_map>
+#include <vector>
+
+#define FRIEND_TEST(test_case_name, test_name) \
+friend class test_case_name##_##test_name##_Test
+
+/* For debug */
+#ifdef DEBUG
+#define debuginfo(fmt, ...) \
+ do {printf("%s():\t" fmt "\t[%s:%d]\n", __FUNCTION__, ##__VA_ARGS__, __FILE__, __LINE__);} \
+ while(0)
+#else
+#define debuginfo(...)
+#endif
+
+#define KMSG_PRIORITY(PRI)                            \
+    '<',                                              \
+    '0' + LOG_MAKEPRI(LOG_DAEMON, LOG_PRI(PRI)) / 10, \
+    '0' + LOG_MAKEPRI(LOG_DAEMON, LOG_PRI(PRI)) % 10, \
+    '>'
+
+static char kmsg_error_prefix[] = { KMSG_PRIORITY(LOG_ERR),
+    's', 't', 'o', 'r', 'a', 'g', 'e', 'd', ':', '\0' };
+
+static char kmsg_info_prefix[] = { KMSG_PRIORITY(LOG_INFO),
+    's', 't', 'o', 'r', 'a', 'g', 'e', 'd', ':', '\0' };
+
+static char kmsg_warning_prefix[] = { KMSG_PRIORITY(LOG_WARNING),
+    's', 't', 'o', 'r', 'a', 'g', 'e', 'd', ':', '\0' };
+
+// number of attributes diskstats has
+#define DISK_STATS_SIZE ( 11 )
+// maximum size limit of a stats file
+#define DISK_STATS_FILE_MAX_SIZE ( 256 )
+#define DISK_STATS_IO_IN_FLIGHT_IDX ( 8 )
+struct disk_stats {
+    /* It will be extremely unlikely for any of the following entries to overflow.
+     * For read_bytes(which will be greater than any of the following entries), it
+     * will take 27 years to overflow uint64_t at the reading rate of 20GB/s, which
+     * is the peak memory transfer rate for current memory.
+     * The diskstats entries (first 11) need to be at top in this structure _after_
+     * compiler's optimization.
+     */
+    uint64_t read_ios;       // number of read I/Os processed
+    uint64_t read_merges;    // number of read I/Os merged with in-queue I/Os
+    uint64_t read_sectors;   // number of sectors read
+    uint64_t read_ticks;     // total wait time for read requests
+    uint64_t write_ios;      // number of write I/Os processed
+    uint64_t write_merges;   // number of write I/Os merged with in-queue I/Os
+    uint64_t write_sectors;  // number of sectors written
+    uint64_t write_ticks;    // total wait time for write requests
+    uint64_t io_in_flight;   // number of I/Os currently in flight
+    uint64_t io_ticks;       // total time this block device has been active
+    uint64_t io_in_queue;    // total wait time for all requests
+
+    uint64_t start_time;     // monotonic time accounting starts
+    uint64_t end_time;       // monotonic time accounting ends
+    uint32_t counter;        // private counter for accumulate calculations
+    double   io_avg;         // average io_in_flight for accumulate calculations
+};
+
+#define MMC_VER_STR_LEN ( 8 )   // maximum length of the MMC version string
+// minimum size of a ext_csd file
+#define EXT_CSD_FILE_MIN_SIZE ( 1024 )
+struct emmc_info {
+    int eol;                        // pre-eol (end of life) information
+    int lifetime_a;                 // device life time estimation (type A)
+    int lifetime_b;                 // device life time estimation (type B)
+    char mmc_ver[MMC_VER_STR_LEN];  // device version string
+};
+
+struct disk_perf {
+    uint32_t read_perf;         // read speed (kbytes/s)
+    uint32_t read_ios;          // read I/Os per second
+    uint32_t write_perf;        // write speed (kbytes/s)
+    uint32_t write_ios;         // write I/Os per second
+    uint32_t queue;             // I/Os in queue
+};
+
+#define CMD_MAX_LEN ( 64 )
+struct task_info {
+    uint32_t pid;                   // task id
+    uint64_t rchar;                 // characters read
+    uint64_t wchar;                 // characters written
+    uint64_t syscr;                 // read syscalls
+    uint64_t syscw;                 // write syscalls
+    uint64_t read_bytes;            // bytes read (from storage layer)
+    uint64_t write_bytes;           // bytes written (to storage layer)
+    uint64_t cancelled_write_bytes; // cancelled write byte by truncate
+
+    uint64_t starttime;             // start time of task
+
+    char cmd[CMD_MAX_LEN];          // filename of the executable
+};
+
+class lock_t {
+    sem_t* mSem;
+public:
+    lock_t(sem_t* sem) {
+        mSem = sem;
+        sem_wait(mSem);
+    }
+    ~lock_t() {
+        sem_post(mSem);
+    }
+};
+
+class tasks_t {
+private:
+    FRIEND_TEST(storaged_test, tasks_t);
+    sem_t mSem;
+    // hashmap for all running tasks w/ pid as key
+    std::unordered_map<uint32_t, struct task_info> mRunning;
+    // hashmap for all tasks that have been killed (categorized by cmd) w/ cmd as key
+    std::unordered_map<std::string, struct task_info> mOld;
+    std::unordered_map<std::uint32_t, struct task_info> get_running_tasks();
+public:
+    tasks_t() {
+        sem_init(&mSem, 0, 1); // TODO: constructor don't have a return value, what if sem_init fails
+    }
+
+    ~tasks_t() {
+        sem_destroy(&mSem);
+    }
+
+    void update_running_tasks(void);
+    std::vector<struct task_info> get_tasks(void);
+};
+
+class stream_stats {
+private:
+    double mSum;
+    double mSquareSum;
+    uint32_t mCnt;
+public:
+    stream_stats() : mSum(0), mSquareSum(0), mCnt(0) {};
+    ~stream_stats() {};
+    double get_mean() {
+        return mSum / mCnt;
+    }
+    double get_std() {
+        return sqrt(mSquareSum / mCnt - mSum * mSum / (mCnt * mCnt));
+    }
+    void add(uint32_t num) {
+        mSum += (double)num;
+        mSquareSum += (double)num * (double)num;
+        mCnt++;
+    }
+    void evict(uint32_t num) {
+        if (mSum < num || mSquareSum < (double)num * (double)num) return;
+        mSum -= (double)num;
+        mSquareSum -= (double)num * (double)num;
+        mCnt--;
+    }
+};
+
+#define MMC_DISK_STATS_PATH "/sys/block/mmcblk0/stat"
+#define SDA_DISK_STATS_PATH "/sys/block/sda/stat"
+#define EMMC_ECSD_PATH "/d/mmc0/mmc0:0001/ext_csd"
+class disk_stats_monitor {
+private:
+    FRIEND_TEST(storaged_test, disk_stats_monitor);
+    const char* DISK_STATS_PATH;
+    struct disk_stats mPrevious;
+    struct disk_stats mAccumulate;
+    bool mStall;
+    std::queue<struct disk_perf> mBuffer;
+    struct {
+        stream_stats read_perf;           // read speed (bytes/s)
+        stream_stats read_ios;            // read I/Os per second
+        stream_stats write_perf;          // write speed (bytes/s)
+        stream_stats write_ios;           // write I/O per second
+        stream_stats queue;               // I/Os in queue
+    } mStats;
+    bool mValid;
+    const uint32_t mWindow;
+    const double mSigma;
+    struct disk_perf mMean;
+    struct disk_perf mStd;
+
+    void update_mean();
+    void update_std();
+    void add(struct disk_perf* perf);
+    void evict(struct disk_perf* perf);
+    bool detect(struct disk_perf* perf);
+
+    void update(struct disk_stats* stats);
+
+public:
+    disk_stats_monitor(uint32_t window_size = 5, double sigma = 1.0) :
+            mStall(false),
+            mValid(false),
+            mWindow(window_size),
+            mSigma(sigma) {
+        memset(&mPrevious, 0, sizeof(mPrevious));
+        memset(&mMean, 0, sizeof(mMean));
+        memset(&mStd, 0, sizeof(mStd));
+
+        if (access(MMC_DISK_STATS_PATH, R_OK) >= 0) {
+            DISK_STATS_PATH = MMC_DISK_STATS_PATH;
+        } else {
+            DISK_STATS_PATH = SDA_DISK_STATS_PATH;
+        }
+    }
+    void update(void);
+};
+
+class disk_stats_publisher {
+private:
+    FRIEND_TEST(storaged_test, disk_stats_publisher);
+    const char* DISK_STATS_PATH;
+    struct disk_stats mAccumulate;
+    struct disk_stats mPrevious;
+public:
+    disk_stats_publisher(void) {
+        memset(&mAccumulate, 0, sizeof(struct disk_stats));
+        memset(&mPrevious, 0, sizeof(struct disk_stats));
+
+        if (access(MMC_DISK_STATS_PATH, R_OK) >= 0) {
+            DISK_STATS_PATH = MMC_DISK_STATS_PATH;
+        } else {
+            DISK_STATS_PATH = SDA_DISK_STATS_PATH;
+        }
+    }
+
+    ~disk_stats_publisher(void) {}
+    void publish(void);
+    void update(void);
+};
+
+class emmc_info_t {
+private:
+    struct emmc_info mInfo;
+    bool mValid;
+    int mFdEmmc;
+public:
+    emmc_info_t(void) :
+            mValid(false),
+            mFdEmmc(-1) {
+        memset(&mInfo, 0, sizeof(struct emmc_info));
+    }
+    ~emmc_info_t(void) {}
+
+    void publish(void);
+    void update(void);
+    void set_emmc_fd(int fd) {
+        mFdEmmc = fd;
+    }
+};
+
+// Periodic chores intervals in seconds
+#define DEFAULT_PERIODIC_CHORES_INTERVAL_UNIT ( 20 )
+#define DEFAULT_PERIODIC_CHORES_INTERVAL_DISK_STATS_PUBLISH ( 60 )
+#define DEFAULT_PERIODIC_CHORES_INTERVAL_EMMC_INFO_PUBLISH ( 60 * 2 )
+
+struct storaged_config {
+    int periodic_chores_interval_unit;
+    int periodic_chores_interval_disk_stats_publish;
+    int periodic_chores_interval_emmc_info_publish;
+    bool proc_taskio_readable;  // are /proc/[pid]/{io, comm, cmdline, stat} all readable
+    bool emmc_available;        // whether eMMC est_csd file is readable
+    bool diskstats_available;   // whether diskstats is accessible
+};
+
+class storaged_t {
+private:
+    time_t mTimer;
+    storaged_config mConfig;
+    disk_stats_publisher mDiskStats;
+    disk_stats_monitor mDsm;
+    emmc_info_t mEmmcInfo;
+    tasks_t mTasks;
+    time_t mStarttime;
+public:
+    storaged_t(void);
+    ~storaged_t() {}
+    void event(void);
+    void pause(void) {
+        sleep(mConfig.periodic_chores_interval_unit);
+    }
+    void set_unit_interval(int unit) {
+        mConfig.periodic_chores_interval_unit = unit;
+    }
+    void set_diskstats_interval(int disk_stats) {
+        mConfig.periodic_chores_interval_disk_stats_publish = disk_stats;
+    }
+    void set_emmc_interval(int emmc_info) {
+        mConfig.periodic_chores_interval_emmc_info_publish = emmc_info;
+    }
+    std::vector<struct task_info> get_tasks(void) {
+        // There could be a race when get_tasks() and the main thread is updating at the same time
+        // While update_running_tasks() is updating the critical sections at the end of the function
+        // all together atomically, the final state of task_t can only be either the main thread's
+        // update or this update. Since the race can only occur when both threads are updating
+        // "simultaneously", either final state is acceptable.
+        mTasks.update_running_tasks();
+        return mTasks.get_tasks();
+    }
+
+    void set_privileged_fds(int fd_emmc) {
+        mEmmcInfo.set_emmc_fd(fd_emmc);
+    }
+
+    time_t get_starttime(void) {
+        return mStarttime;
+    }
+};
+
+// Eventlog tag
+// The content must match the definition in EventLogTags.logtags
+#define EVENTLOGTAG_DISKSTATS ( 2732 )
+#define EVENTLOGTAG_EMMCINFO ( 2733 )
+
+#endif /* _STORAGED_H_ */
diff --git a/storaged/include/storaged_service.h b/storaged/include/storaged_service.h
new file mode 100644
index 0000000..64a9c81
--- /dev/null
+++ b/storaged/include/storaged_service.h
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 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.
+ */
+
+#ifndef _STORAGED_SERVICE_H_
+#define _STORAGED_SERVICE_H_
+
+#include <vector>
+
+#include <binder/IInterface.h>
+#include <binder/IBinder.h>
+
+#include "storaged.h"
+
+using namespace android;
+
+// Interface
+class IStoraged : public IInterface {
+public:
+    enum {
+        DUMPTASKS = IBinder::FIRST_CALL_TRANSACTION,
+    };
+    // Request the service to run the test function
+    virtual std::vector<struct task_info> dump_tasks(const char* option) = 0;
+
+    DECLARE_META_INTERFACE(Storaged);
+};
+
+// Client
+class BpStoraged : public BpInterface<IStoraged> {
+public:
+    BpStoraged(const sp<IBinder>& impl) : BpInterface<IStoraged>(impl){};
+    virtual std::vector<struct task_info> dump_tasks(const char* option);
+};
+
+// Server
+class BnStoraged : public BnInterface<IStoraged> {
+    virtual status_t onTransact(uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags = 0);
+};
+
+class Storaged : public BnStoraged {
+    virtual std::vector<struct task_info> dump_tasks(const char* option);
+};
+
+sp<IStoraged> get_storaged_service();
+
+#endif /* _STORAGED_SERVICE_H_ */
\ No newline at end of file
diff --git a/storaged/include/storaged_utils.h b/storaged/include/storaged_utils.h
new file mode 100644
index 0000000..b0e5146
--- /dev/null
+++ b/storaged/include/storaged_utils.h
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 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.
+ */
+
+#ifndef _STORAGED_UTILS_H_
+#define _STORAGED_UTILS_H_
+
+#include <stdint.h>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+#include "storaged.h"
+
+// Diskstats
+bool parse_disk_stats(const char* disk_stats_path, struct disk_stats* stats);
+struct disk_perf get_disk_perf(struct disk_stats* stats);
+struct disk_stats get_inc_disk_stats(struct disk_stats* prev, struct disk_stats* curr);
+void add_disk_stats(struct disk_stats* src, struct disk_stats* dst);
+bool parse_emmc_ecsd(int ext_csd_fd, struct emmc_info* info);
+
+// Task I/O
+bool parse_task_info(uint32_t pid, struct task_info* info);
+void sort_running_tasks_info(std::vector<struct task_info> &tasks);
+
+// Logging
+void log_console_running_tasks_info(std::vector<struct task_info> tasks);
+void log_kernel_disk_stats(struct disk_stats* stats, const char* type);
+void log_kernel_disk_perf(struct disk_perf* perf, const char* type);
+void log_kernel_emmc_info(struct emmc_info* info);
+
+void log_event_disk_stats(struct disk_stats* stats, const char* type);
+void log_event_emmc_info(struct emmc_info* info_);
+#endif /* _STORAGED_UTILS_H_ */
\ No newline at end of file
diff --git a/storaged/main.cpp b/storaged/main.cpp
new file mode 100644
index 0000000..bd1166a
--- /dev/null
+++ b/storaged/main.cpp
@@ -0,0 +1,298 @@
+/*
+ * Copyright (C) 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.
+ */
+
+#define LOG_TAG "storaged"
+#define KLOG_LEVEL 6
+
+#include <fcntl.h>
+#include <getopt.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <sys/capability.h>
+#include <sys/prctl.h>
+#include <sys/resource.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <vector>
+
+#include <android-base/macros.h>
+#include <android-base/stringprintf.h>
+#include <binder/ProcessState.h>
+#include <binder/IServiceManager.h>
+#include <binder/IPCThreadState.h>
+#include <cutils/android_get_control_file.h>
+#include <cutils/klog.h>
+#include <cutils/sched_policy.h>
+#include <private/android_filesystem_config.h>
+
+#include <storaged.h>
+#include <storaged_service.h>
+#include <storaged_utils.h>
+
+storaged_t storaged;
+
+static int drop_privs() {
+    // privilege setting
+    struct sched_param param;
+    memset(&param, 0, sizeof(param));
+
+    if (set_sched_policy(0, SP_BACKGROUND) < 0) return -1;
+
+    if (sched_setscheduler((pid_t) 0, SCHED_BATCH, &param) < 0) return -1;
+
+    if (setpriority(PRIO_PROCESS, 0, ANDROID_PRIORITY_BACKGROUND) < 0) return -1;
+
+    if (prctl(PR_SET_KEEPCAPS, 1) < 0) return -1;
+
+    std::unique_ptr<struct _cap_struct, int(*)(void *)> caps(cap_init(), cap_free);
+    if (cap_clear(caps.get()) < 0) return -1;
+    cap_value_t cap_value[] = {
+        CAP_SETGID,
+        CAP_SETUID,
+        CAP_SYS_PTRACE // allow access to proc/<pid>/io as non-root user
+    };
+    if (cap_set_flag(caps.get(), CAP_PERMITTED,
+                     arraysize(cap_value), cap_value,
+                     CAP_SET) < 0) return -1;
+    if (cap_set_flag(caps.get(), CAP_EFFECTIVE,
+                     arraysize(cap_value), cap_value,
+                     CAP_SET) < 0) return -1;
+    if (cap_set_proc(caps.get()) < 0)
+        return -1;
+
+    gid_t groups[] = { AID_READPROC };
+
+    if (setgroups(sizeof(groups) / sizeof(groups[0]), groups) == -1) return -1;
+
+    if (setgid(AID_SYSTEM) != 0) return -1;
+
+    if (setuid(AID_SYSTEM) != 0) return -1;
+
+    if (cap_set_flag(caps.get(), CAP_PERMITTED, 2, cap_value, CAP_CLEAR) < 0) return -1;
+    if (cap_set_flag(caps.get(), CAP_EFFECTIVE, 2, cap_value, CAP_CLEAR) < 0) return -1;
+    if (cap_set_proc(caps.get()) < 0)
+        return -1;
+
+    return 0;
+}
+
+// Function of storaged's main thread
+extern int fd_dmesg;
+void* storaged_main(void* s) {
+    storaged_t* storaged = (storaged_t*)s;
+
+    if (fd_dmesg >= 0) {
+        static const char start_message[] = {KMSG_PRIORITY(LOG_INFO),
+            's', 't', 'o', 'r', 'a', 'g', 'e', 'd', ':', ' ', 'S', 't', 'a', 'r', 't', '\n'};
+        write(fd_dmesg, start_message, sizeof(start_message));
+    }
+
+    for (;;) {
+        storaged->event();
+        storaged->pause();
+    }
+    return NULL;
+}
+
+static void help_message(void) {
+    printf("usage: storaged [OPTION]\n");
+    printf("  -d    --dump                  Dump task I/O usage to stdout\n");
+    printf("  -s    --start                 Start storaged (default)\n");
+    printf("        --emmc=INTERVAL         Set publish interval of emmc lifetime information (in days)\n");
+    printf("        --diskstats=INTERVAL    Set publish interval of diskstats (in hours)\n");
+    printf("        --unit=INTERVAL         Set storaged's refresh interval (in seconds)\n");
+    fflush(stdout);
+}
+
+#define HOUR_TO_SEC ( 3600 )
+#define DAY_TO_SEC ( 3600 * 24 )
+
+int main(int argc, char** argv) {
+    klog_set_level(KLOG_LEVEL);
+    int flag_main_service = 0;
+    int flag_dump_task = 0;
+    int flag_config = 0;
+    int unit_interval = DEFAULT_PERIODIC_CHORES_INTERVAL_UNIT;
+    int diskstats_interval = DEFAULT_PERIODIC_CHORES_INTERVAL_DISK_STATS_PUBLISH;
+    int emmc_interval = DEFAULT_PERIODIC_CHORES_INTERVAL_EMMC_INFO_PUBLISH;
+    int fd_emmc = -1;
+    int opt;
+
+    for (;;) {
+        int opt_idx = 0;
+        static struct option long_options[] = {
+            {"start",       no_argument,        0, 's'},
+            {"kill",        no_argument,        0, 'k'},
+            {"dump",        no_argument,        0, 'd'},
+            {"help",        no_argument,        0, 'h'},
+            {"unit",        required_argument,  0,  0 },
+            {"diskstats",   required_argument,  0,  0 },
+            {"emmc",        required_argument,  0,  0 }
+        };
+        opt = getopt_long(argc, argv, ":skdh0", long_options, &opt_idx);
+        if (opt == -1) {
+            break;
+        }
+
+        switch (opt) {
+        case 0:
+            printf("option %s", long_options[opt_idx].name);
+            if (optarg) {
+                printf(" with arg %s", optarg);
+                if (strcmp(long_options[opt_idx].name, "unit") == 0) {
+                    unit_interval = atoi(optarg);
+                    if (unit_interval == 0) {
+                        fprintf(stderr, "Invalid argument. Option %s requires an integer argument greater than 0.\n",
+                                long_options[opt_idx].name);
+                        help_message();
+                        return -1;
+                    }
+                } else if (strcmp(long_options[opt_idx].name, "diskstats") == 0) {
+                    diskstats_interval = atoi(optarg) * HOUR_TO_SEC;
+                    if (diskstats_interval == 0) {
+                        fprintf(stderr, "Invalid argument. Option %s requires an integer argument greater than 0.\n",
+                                long_options[opt_idx].name);
+                        help_message();
+                        return -1;
+                    }
+
+                } else if (strcmp(long_options[opt_idx].name, "emmc") == 0) {
+                    emmc_interval = atoi(optarg) * DAY_TO_SEC;
+                    if (diskstats_interval == 0) {
+                        fprintf(stderr, "Invalid argument. Option %s requires an integer argument greater than 0.\n",
+                                long_options[opt_idx].name);
+                        help_message();
+                        return -1;
+                    }
+                }
+                flag_config = 1;
+            } else {
+                fprintf(stderr, "Invalid argument. Option %s requires an argument.\n",
+                        long_options[opt_idx].name);
+                help_message();
+                return -1;
+            }
+            printf("\n");
+            break;
+        case 's':
+            flag_main_service = 1;
+            break;
+        case 'd':
+            flag_dump_task = 1;
+            break;
+        case 'h':
+            help_message();
+            return 0;
+        case '?':
+        default:
+            fprintf(stderr, "no supported option\n");
+            help_message();
+            return -1;
+        }
+    }
+
+    if (argc == 1) {
+        flag_main_service = 1;
+    }
+
+    if (flag_main_service && flag_dump_task) {
+        fprintf(stderr, "Invalid arguments. Option \"start\" and \"dump\" cannot be used together.\n");
+        help_message();
+        return -1;
+    }
+
+    if (flag_config && flag_dump_task) {
+        fprintf(stderr, "Invalid arguments. Cannot set configs in \'dump\' option.\n");
+        help_message();
+        return -1;
+    }
+
+    if (flag_main_service) { // start main thread
+        static const char dev_kmsg[] = "/dev/kmsg";
+        fd_dmesg = android_get_control_file(dev_kmsg);
+        if (fd_dmesg < 0)
+            fd_dmesg = TEMP_FAILURE_RETRY(open(dev_kmsg, O_WRONLY));
+
+        static const char mmc0_ext_csd[] = "/d/mmc0/mmc0:0001/ext_csd";
+        fd_emmc = android_get_control_file(mmc0_ext_csd);
+        if (fd_emmc < 0)
+            fd_emmc = TEMP_FAILURE_RETRY(open(mmc0_ext_csd, O_RDONLY));
+
+        if (drop_privs() != 0) {
+            return -1;
+        }
+
+        storaged.set_privileged_fds(fd_emmc);
+
+        if (flag_config) {
+            storaged.set_unit_interval(unit_interval);
+            storaged.set_diskstats_interval(diskstats_interval);
+            storaged.set_emmc_interval(emmc_interval);
+        }
+
+        // Start the main thread of storaged
+        pthread_t storaged_main_thread;
+        if (pthread_create(&storaged_main_thread, NULL, storaged_main, &storaged)) {
+            if (fd_dmesg >= 0) {
+                std::string error_message = android::base::StringPrintf(
+                    "%s Failed to create main thread\n", kmsg_error_prefix);
+                write(fd_dmesg, error_message.c_str(), error_message.length());
+            }
+            return -1;
+        }
+
+        defaultServiceManager()->addService(String16("storaged"), new Storaged());
+        android::ProcessState::self()->startThreadPool();
+        IPCThreadState::self()->joinThreadPool();
+        pthread_join(storaged_main_thread, NULL);
+
+        close(fd_dmesg);
+        close(fd_emmc);
+
+        return 0;
+    }
+
+    if (flag_dump_task) {
+        sp<IStoraged> storaged_service = get_storaged_service();
+        if (storaged_service == NULL) {
+            fprintf(stderr, "Cannot find storaged service.\nMaybe run storaged --start first?\n");
+            return -1;
+        }
+        std::vector<struct task_info> res = storaged_service->dump_tasks(NULL);
+
+        if (res.size() == 0) {
+            fprintf(stderr, "Task I/O is not readable in this version of kernel.\n");
+            return 0;
+        }
+
+        time_t starttime = storaged.get_starttime();
+
+        if (starttime == (time_t)-1) {
+            fprintf(stderr, "Unknown start time\n");
+        } else {
+            char* time_str = ctime(&starttime);
+            printf("Application I/O was collected by storaged since %s", time_str);
+        }
+
+        sort_running_tasks_info(res);
+        log_console_running_tasks_info(res);
+
+
+        return 0;
+    }
+
+    return 0;
+}
\ No newline at end of file
diff --git a/storaged/storaged.cpp b/storaged/storaged.cpp
new file mode 100644
index 0000000..1402208
--- /dev/null
+++ b/storaged/storaged.cpp
@@ -0,0 +1,211 @@
+/*
+ * Copyright (C) 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.
+ */
+
+#define LOG_TAG "storaged"
+
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+
+
+#include <android-base/logging.h>
+
+#include <storaged.h>
+#include <storaged_utils.h>
+
+/* disk_stats_publisher */
+void disk_stats_publisher::publish(void) {
+    // Logging
+    log_kernel_disk_stats(&mAccumulate, "regular");
+    struct disk_perf perf = get_disk_perf(&mAccumulate);
+    log_kernel_disk_perf(&perf, "regular");
+    log_event_disk_stats(&mAccumulate, "regular");
+    // Reset global structures
+    memset(&mAccumulate, 0, sizeof(struct disk_stats));
+}
+
+void disk_stats_publisher::update(void) {
+    struct disk_stats curr;
+    if (parse_disk_stats(DISK_STATS_PATH, &curr)) {
+        struct disk_stats inc = get_inc_disk_stats(&mPrevious, &curr);
+        add_disk_stats(&inc, &mAccumulate);
+        #ifdef DEBUG
+//            log_kernel_disk_stats(&mPrevious, "prev stats");
+//            log_kernel_disk_stats(&curr, "curr stats");
+//            log_kernel_disk_stats(&inc, "inc stats");
+//            log_kernel_disk_stats(&mAccumulate, "accumulated stats");
+        #endif
+        mPrevious = curr;
+    }
+}
+
+/* disk_stats_monitor */
+void disk_stats_monitor::update_mean() {
+    CHECK(mValid);
+    mMean.read_perf = (uint32_t)mStats.read_perf.get_mean();
+    mMean.read_ios = (uint32_t)mStats.read_ios.get_mean();
+    mMean.write_perf = (uint32_t)mStats.write_perf.get_mean();
+    mMean.write_ios = (uint32_t)mStats.write_ios.get_mean();
+    mMean.queue = (uint32_t)mStats.queue.get_mean();
+}
+
+void disk_stats_monitor::update_std() {
+    CHECK(mValid);
+    mStd.read_perf = (uint32_t)mStats.read_perf.get_std();
+    mStd.read_ios = (uint32_t)mStats.read_ios.get_std();
+    mStd.write_perf = (uint32_t)mStats.write_perf.get_std();
+    mStd.write_ios = (uint32_t)mStats.write_ios.get_std();
+    mStd.queue = (uint32_t)mStats.queue.get_std();
+}
+
+void disk_stats_monitor::add(struct disk_perf* perf) {
+    mStats.read_perf.add(perf->read_perf);
+    mStats.read_ios.add(perf->read_ios);
+    mStats.write_perf.add(perf->write_perf);
+    mStats.write_ios.add(perf->write_ios);
+    mStats.queue.add(perf->queue);
+}
+
+void disk_stats_monitor::evict(struct disk_perf* perf) {
+    mStats.read_perf.evict(perf->read_perf);
+    mStats.read_ios.evict(perf->read_ios);
+    mStats.write_perf.evict(perf->write_perf);
+    mStats.write_ios.evict(perf->write_ios);
+    mStats.queue.evict(perf->queue);
+}
+
+bool disk_stats_monitor::detect(struct disk_perf* perf) {
+    return ((double)perf->queue >= (double)mMean.queue + mSigma * (double)mStd.queue) &&
+            ((double)perf->read_perf < (double)mMean.read_perf - mSigma * (double)mStd.read_perf) &&
+            ((double)perf->write_perf < (double)mMean.write_perf - mSigma * (double)mStd.write_perf);
+}
+
+void disk_stats_monitor::update(struct disk_stats* stats) {
+    struct disk_stats inc = get_inc_disk_stats(&mPrevious, stats);
+    struct disk_perf perf = get_disk_perf(&inc);
+    // Update internal data structures
+    if (LIKELY(mValid)) {
+        CHECK_EQ(mBuffer.size(), mWindow);
+
+        if (UNLIKELY(detect(&perf))) {
+            mStall = true;
+            add_disk_stats(&inc, &mAccumulate);
+            #ifdef DEBUG
+            log_kernel_disk_perf(&mMean, "stalled_mean");
+            log_kernel_disk_perf(&mStd, "stalled_std");
+            #endif
+        } else {
+            if (mStall) {
+                log_kernel_disk_stats(&mAccumulate, "stalled");
+                struct disk_perf acc_perf = get_disk_perf(&mAccumulate);
+                log_kernel_disk_perf(&acc_perf, "stalled");
+
+                log_event_disk_stats(&mAccumulate, "stalled");
+                mStall = false;
+                memset(&mAccumulate, 0, sizeof(mAccumulate));
+            }
+        }
+
+        evict(&mBuffer.front());
+        mBuffer.pop();
+        add(&perf);
+        mBuffer.push(perf);
+
+        update_mean();
+        update_std();
+
+    } else { /* mValid == false */
+        CHECK_LT(mBuffer.size(), mWindow);
+        add(&perf);
+        mBuffer.push(perf);
+        if (mBuffer.size() == mWindow) {
+            mValid = true;
+            update_mean();
+            update_std();
+        }
+    }
+
+    mPrevious = *stats;
+}
+
+void disk_stats_monitor::update(void) {
+    struct disk_stats curr;
+    if (LIKELY(parse_disk_stats(DISK_STATS_PATH, &curr))) {
+        update(&curr);
+    }
+}
+
+/* emmc_info_t */
+void emmc_info_t::publish(void) {
+    if (mValid) {
+        log_kernel_emmc_info(&mInfo);
+        log_event_emmc_info(&mInfo);
+    }
+}
+
+void emmc_info_t::update(void) {
+    if (mFdEmmc >= 0) {
+        mValid = parse_emmc_ecsd(mFdEmmc, &mInfo);
+    }
+}
+
+/* storaged_t */
+storaged_t::storaged_t(void) {
+    mConfig.emmc_available = (access(EMMC_ECSD_PATH, R_OK) >= 0);
+
+    if (access(MMC_DISK_STATS_PATH, R_OK) < 0 && access(SDA_DISK_STATS_PATH, R_OK) < 0) {
+        mConfig.diskstats_available = false;
+    } else {
+        mConfig.diskstats_available = true;
+    }
+
+    mConfig.proc_taskio_readable = true;
+    const char* test_paths[] = {"/proc/1/io", "/proc/1/comm", "/proc/1/cmdline", "/proc/1/stat"};
+    for (uint i = 0; i < sizeof(test_paths) / sizeof(const char*); ++i) {
+        if (access(test_paths[i], R_OK) < 0) {
+            mConfig.proc_taskio_readable = false;
+            break;
+        }
+    }
+
+    mConfig.periodic_chores_interval_unit = DEFAULT_PERIODIC_CHORES_INTERVAL_UNIT;
+    mConfig.periodic_chores_interval_disk_stats_publish = DEFAULT_PERIODIC_CHORES_INTERVAL_DISK_STATS_PUBLISH;
+    mConfig.periodic_chores_interval_emmc_info_publish = DEFAULT_PERIODIC_CHORES_INTERVAL_EMMC_INFO_PUBLISH;
+
+    mStarttime = time(NULL);
+}
+
+void storaged_t::event(void) {
+    if (mConfig.diskstats_available) {
+        mDiskStats.update();
+        mDsm.update();
+        if (mTimer && (mTimer % mConfig.periodic_chores_interval_disk_stats_publish) == 0) {
+            mDiskStats.publish();
+        }
+    }
+
+    if (mConfig.proc_taskio_readable) {
+        mTasks.update_running_tasks();
+    }
+
+    if (mConfig.emmc_available && mTimer &&
+            (mTimer % mConfig.periodic_chores_interval_emmc_info_publish) == 0) {
+        mEmmcInfo.update();
+        mEmmcInfo.publish();
+    }
+
+    mTimer += mConfig.periodic_chores_interval_unit;
+}
\ No newline at end of file
diff --git a/storaged/storaged.rc b/storaged/storaged.rc
new file mode 100644
index 0000000..f72521c
--- /dev/null
+++ b/storaged/storaged.rc
@@ -0,0 +1,5 @@
+service storaged /system/bin/storaged
+    class main
+    file /d/mmc0/mmc0:0001/ext_csd r
+    file /dev/kmsg w
+    group root readproc
diff --git a/storaged/storaged_service.cpp b/storaged/storaged_service.cpp
new file mode 100644
index 0000000..aa38ceb
--- /dev/null
+++ b/storaged/storaged_service.cpp
@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 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 <vector>
+
+#include <binder/IBinder.h>
+#include <binder/IInterface.h>
+
+#include <binder/IPCThreadState.h>
+#include <binder/IServiceManager.h>
+
+#include <storaged.h>
+#include <storaged_service.h>
+
+extern storaged_t storaged;
+
+std::vector<struct task_info> BpStoraged::dump_tasks(const char* /*option*/) {
+    Parcel data, reply;
+    data.writeInterfaceToken(IStoraged::getInterfaceDescriptor());
+
+    remote()->transact(DUMPTASKS, data, &reply);
+
+    uint32_t res_size = reply.readInt32();
+    std::vector<struct task_info> res(res_size);
+    for (auto&& task : res) {
+        reply.read(&task, sizeof(task));
+    }
+    return res;
+}
+
+IMPLEMENT_META_INTERFACE(Storaged, "Storaged");
+
+status_t BnStoraged::onTransact(uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags) {
+    data.checkInterface(this);
+
+    switch(code) {
+        case DUMPTASKS: {
+                std::vector<struct task_info> res = dump_tasks(NULL);
+
+                reply->writeInt32(res.size());
+                for (auto task : res) {
+                    reply->write(&task, sizeof(task));
+                }
+                return NO_ERROR;
+            }
+            break;
+        default:
+            return BBinder::onTransact(code, data, reply, flags);
+    }
+}
+std::vector<struct task_info> Storaged::dump_tasks(const char* /* option */) {
+    return storaged.get_tasks();
+}
+
+sp<IStoraged> get_storaged_service() {
+    sp<IServiceManager> sm = defaultServiceManager();
+    if (sm == NULL) return NULL;
+
+    sp<IBinder> binder = sm->getService(String16("storaged"));
+    if (binder == NULL) return NULL;
+
+    sp<IStoraged> storaged = interface_cast<IStoraged>(binder);
+
+    return storaged;
+}
\ No newline at end of file
diff --git a/storaged/storaged_utils.cpp b/storaged/storaged_utils.cpp
new file mode 100644
index 0000000..9c0b625
--- /dev/null
+++ b/storaged/storaged_utils.cpp
@@ -0,0 +1,582 @@
+/*
+ * Copyright (C) 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.
+ */
+
+#define LOG_TAG "storaged"
+
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <linux/time.h>
+
+#include <dirent.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <sstream>
+#include <string>
+#include <unordered_map>
+
+#include <android-base/file.h>
+#include <android-base/stringprintf.h>
+#include <android-base/strings.h>
+#include <android-base/logging.h>
+#include <log/log.h>
+#include <log/log_event_list.h>
+#include <cutils/klog.h>
+
+#include <storaged.h>
+#include <storaged_utils.h>
+
+#include <time.h>
+
+#define SECTOR_SIZE ( 512 )
+#define SEC_TO_MSEC ( 1000 )
+#define MSEC_TO_USEC ( 1000 )
+#define USEC_TO_NSEC ( 1000 )
+
+int fd_dmesg = -1;
+
+bool parse_disk_stats(const char* disk_stats_path, struct disk_stats* stats) {
+    // Get time
+    struct timespec ts;
+    // Use monotonic to exclude suspend time so that we measure IO bytes/sec
+    // when system is running.
+    int ret = clock_gettime(CLOCK_MONOTONIC, &ts);
+    if (ret < 0) {
+        if (fd_dmesg >= 0) {
+            std::string error_message = android::base::StringPrintf(
+                "%s clock_gettime() failed with errno %d\n",
+                kmsg_error_prefix, ret);
+            write(fd_dmesg, error_message.c_str(), error_message.length());
+        }
+        return false;
+    }
+
+    std::string buffer;
+    if (!android::base::ReadFileToString(disk_stats_path, &buffer)) {
+        if (fd_dmesg >= 0) {
+            std::string error_message = android::base::StringPrintf(
+                "%s %s: ReadFileToString failed.\n", kmsg_error_prefix, disk_stats_path);
+            write(fd_dmesg, error_message.c_str(), error_message.length());
+        }
+        return false;
+    }
+
+    // Regular diskstats entries
+    std::stringstream ss(buffer);
+    for (uint i = 0; i < DISK_STATS_SIZE; ++i) {
+        ss >> *((uint64_t*)stats + i);
+    }
+    // Other entries
+    stats->start_time = 0;
+    stats->end_time = (uint64_t)ts.tv_sec * SEC_TO_MSEC +
+        ts.tv_nsec / (MSEC_TO_USEC * USEC_TO_NSEC);
+    stats->counter = 1;
+    stats->io_avg = (double)stats->io_in_flight;
+    return true;
+}
+
+struct disk_perf get_disk_perf(struct disk_stats* stats) {
+    struct disk_perf perf;
+    memset(&perf, 0, sizeof(struct disk_perf));  // initialize
+
+    if (stats->io_ticks) {
+        if (stats->read_ticks) {
+            unsigned long long divisor = stats->read_ticks * stats->io_ticks;
+            perf.read_perf = ((unsigned long long)SECTOR_SIZE *
+                                        stats->read_sectors *
+                                        stats->io_in_queue +
+                                        (divisor >> 1)) /
+                                            divisor;
+            perf.read_ios = ((unsigned long long)SEC_TO_MSEC *
+                                        stats->read_ios *
+                                        stats->io_in_queue +
+                                        (divisor >> 1)) /
+                                            divisor;
+        }
+        if (stats->write_ticks) {
+            unsigned long long divisor = stats->write_ticks * stats->io_ticks;
+                        perf.write_perf = ((unsigned long long)SECTOR_SIZE *
+                                                    stats->write_sectors *
+                                                    stats->io_in_queue +
+                                                    (divisor >> 1)) /
+                                                        divisor;
+                        perf.write_ios = ((unsigned long long)SEC_TO_MSEC *
+                                                    stats->write_ios *
+                                                    stats->io_in_queue +
+                                                    (divisor >> 1)) /
+                                                        divisor;
+        }
+        perf.queue = (stats->io_in_queue + (stats->io_ticks >> 1)) /
+                                stats->io_ticks;
+    }
+    return perf;
+}
+
+struct disk_stats get_inc_disk_stats(struct disk_stats* prev, struct disk_stats* curr) {
+    struct disk_stats inc;
+    for (uint i = 0; i < DISK_STATS_SIZE; ++i) {
+        if (i == DISK_STATS_IO_IN_FLIGHT_IDX) {
+            continue;
+        }
+
+        *((uint64_t*)&inc + i) =
+                *((uint64_t*)curr + i) - *((uint64_t*)prev + i);
+    }
+    // io_in_flight is exception
+    inc.io_in_flight = curr->io_in_flight;
+
+    inc.start_time = prev->end_time;
+    inc.end_time = curr->end_time;
+    inc.io_avg = curr->io_avg;
+    inc.counter = 1;
+
+    return inc;
+}
+
+// Add src to dst
+void add_disk_stats(struct disk_stats* src, struct disk_stats* dst) {
+    if (dst->end_time != 0 && dst->end_time != src->start_time && fd_dmesg >= 0) {
+        std::string warning_message = android::base::StringPrintf(
+            "%s Two dis-continuous periods of diskstats are added. "
+            "dst end with %jd, src start with %jd\n",
+            kmsg_warning_prefix, dst->end_time, src->start_time);
+
+        write(fd_dmesg, warning_message.c_str(), warning_message.length());
+    }
+
+    for (uint i = 0; i < DISK_STATS_SIZE; ++i) {
+        if (i == DISK_STATS_IO_IN_FLIGHT_IDX) {
+            continue;
+        }
+
+        *((uint64_t*)dst + i) += *((uint64_t*)src + i);
+    }
+
+    dst->io_in_flight = src->io_in_flight;
+    if (dst->counter + src->counter) {
+        dst->io_avg = ((dst->io_avg * dst->counter) + (src->io_avg * src->counter)) /
+                        (dst->counter + src->counter);
+    }
+    dst->counter += src->counter;
+    dst->end_time = src->end_time;
+    if (dst->start_time == 0) {
+        dst->start_time = src->start_time;
+    }
+}
+
+bool parse_emmc_ecsd(int ext_csd_fd, struct emmc_info* info) {
+    CHECK(ext_csd_fd >= 0);
+    struct hex {
+        char str[2];
+    };
+    // List of interesting offsets
+    static const size_t EXT_CSD_REV_IDX = 192 * sizeof(hex);
+    static const size_t EXT_PRE_EOL_INFO_IDX = 267 * sizeof(hex);
+    static const size_t EXT_DEVICE_LIFE_TIME_EST_A_IDX = 268 * sizeof(hex);
+    static const size_t EXT_DEVICE_LIFE_TIME_EST_B_IDX = 269 * sizeof(hex);
+
+    // Read file
+    CHECK(lseek(ext_csd_fd, 0, SEEK_SET) == 0);
+    std::string buffer;
+    if (!android::base::ReadFdToString(ext_csd_fd, &buffer)) {
+        if (fd_dmesg >= 0) {
+            std::string error_message = android::base::StringPrintf(
+                "%s ReadFdToString failed.\n", kmsg_error_prefix);
+            write(fd_dmesg, error_message.c_str(), error_message.length());
+        }
+        return false;
+    }
+
+    if (buffer.length() < EXT_CSD_FILE_MIN_SIZE) {
+        if (fd_dmesg >= 0) {
+            std::string error_message = android::base::StringPrintf(
+                "%s EMMC ext csd file has truncated content. File length: %d\n",
+                kmsg_error_prefix, (int)buffer.length());
+            write(fd_dmesg, error_message.c_str(), error_message.length());
+        }
+        return false;
+    }
+
+    std::string sub;
+    std::stringstream ss;
+    // Parse EXT_CSD_REV
+    int ext_csd_rev = -1;
+    sub = buffer.substr(EXT_CSD_REV_IDX, sizeof(hex));
+    ss << sub;
+    ss >> std::hex >> ext_csd_rev;
+    if (ext_csd_rev < 0) {
+        if (fd_dmesg >= 0) {
+            std::string error_message = android::base::StringPrintf(
+                "%s Failure on parsing EXT_CSD_REV.\n", kmsg_error_prefix);
+            write(fd_dmesg, error_message.c_str(), error_message.length());
+        }
+        return false;
+    }
+    ss.clear();
+
+    static const char* ver_str[] = {
+        "4.0", "4.1", "4.2", "4.3", "Obsolete", "4.41", "4.5", "5.0"
+    };
+
+    strncpy(info->mmc_ver,
+            (ext_csd_rev < (int)(sizeof(ver_str) / sizeof(ver_str[0]))) ?
+                           ver_str[ext_csd_rev] :
+                           "Unknown",
+            MMC_VER_STR_LEN);
+
+    if (ext_csd_rev < 7) {
+        return 0;
+    }
+
+    // Parse EXT_PRE_EOL_INFO
+    info->eol = -1;
+    sub = buffer.substr(EXT_PRE_EOL_INFO_IDX, sizeof(hex));
+    ss << sub;
+    ss >> std::hex >> info->eol;
+    if (info->eol < 0) {
+        if (fd_dmesg >= 0) {
+            std::string error_message = android::base::StringPrintf(
+                "%s Failure on parsing EXT_PRE_EOL_INFO.\n", kmsg_error_prefix);
+            write(fd_dmesg, error_message.c_str(), error_message.length());
+        }
+        return false;
+    }
+    ss.clear();
+
+    // Parse DEVICE_LIFE_TIME_EST
+    info->lifetime_a = -1;
+    sub = buffer.substr(EXT_DEVICE_LIFE_TIME_EST_A_IDX, sizeof(hex));
+    ss << sub;
+    ss >> std::hex >> info->lifetime_a;
+    if (info->lifetime_a < 0) {
+        if (fd_dmesg >= 0) {
+            std::string error_message = android::base::StringPrintf(
+                "%s Failure on parsing EXT_DEVICE_LIFE_TIME_EST_TYP_A.\n", kmsg_error_prefix);
+            write(fd_dmesg, error_message.c_str(), error_message.length());
+        }
+        return false;
+    }
+    ss.clear();
+
+    info->lifetime_b = -1;
+    sub = buffer.substr(EXT_DEVICE_LIFE_TIME_EST_B_IDX, sizeof(hex));
+    ss << sub;
+    ss >> std::hex >> info->lifetime_b;
+    if (info->lifetime_b < 0) {
+        if (fd_dmesg >= 0) {
+            std::string error_message = android::base::StringPrintf(
+                "%s Failure on parsing EXT_DEVICE_LIFE_TIME_EST_TYP_B.\n", kmsg_error_prefix);
+            write(fd_dmesg, error_message.c_str(), error_message.length());
+        }
+        return false;
+    }
+    ss.clear();
+
+    return true;
+}
+
+#define PROC_DIR "/proc/"
+#define PROC_STAT_STARTTIME_IDX ( 22 ) // This index is 1 based according to the linux proc man page
+bool parse_task_info(uint32_t pid, struct task_info* info) {
+    std::string buffer;
+    std::string pid_str = std::to_string(pid);
+    info->pid = pid;
+
+    // Get task I/O
+    std::string task_io_path = android::base::StringPrintf(PROC_DIR "%s/io", pid_str.c_str());
+    if (!android::base::ReadFileToString(task_io_path, &buffer)) return false;
+
+    std::stringstream ss(buffer);
+    std::string title;
+
+    ss >> title >> info->rchar
+       >> title >> info->wchar
+       >> title >> info->syscr
+       >> title >> info->syscw
+       >> title >> info->read_bytes
+       >> title >> info->write_bytes
+       >> title >> info->cancelled_write_bytes;
+    ss.clear();
+
+    // Get cmd string
+    std::string task_cmdline_path = android::base::StringPrintf(PROC_DIR "%u/cmdline", pid);
+    if (!android::base::ReadFileToString(task_cmdline_path, &buffer)) return false;
+    strcpy(info->cmd, android::base::Trim(buffer).c_str());
+
+    if (info->cmd[0] == '\0') {
+        std::string task_comm_path = android::base::StringPrintf(PROC_DIR "%u/comm", pid);
+        if (!android::base::ReadFileToString(task_comm_path, &buffer)) return false;
+        strcpy(info->cmd, android::base::Trim(buffer).c_str());
+    }
+
+    // Get task start time
+    std::string task_stat_path = android::base::StringPrintf(PROC_DIR "%u/stat", pid);
+    if (!android::base::ReadFileToString(task_stat_path, &buffer)) return false;
+
+    std::vector<std::string> stat_parts = android::base::Split(buffer, " ");
+    info->starttime = atoll(stat_parts[PROC_STAT_STARTTIME_IDX - 1].c_str());
+
+    return true;
+}
+
+static bool is_pid(char* d_name) {
+    if (!d_name || d_name[0] == '\0') return false;
+    char* c = d_name;
+    while (*c) {
+        if (!isdigit(*c)) return false;
+        ++c;
+    }
+    return true;
+}
+
+static bool cmp_task_info(struct task_info i, struct task_info j) {
+    if (i.write_bytes + i.read_bytes != j.write_bytes + j.read_bytes) {
+        return i.write_bytes + i.read_bytes > j.write_bytes + j.read_bytes;
+    }
+    if (i.wchar + i.rchar != j.wchar + j.rchar) {
+        return i.wchar + i.rchar > j.wchar + j.rchar;
+    }
+    if (i.syscw + i.syscr != j.syscw + j.syscr) {
+        return i.syscw + i.syscr > j.syscw + j.syscr;
+    }
+
+    return strcmp(i.cmd, j.cmd) < 0;
+}
+
+std::unordered_map<uint32_t, struct task_info> tasks_t::get_running_tasks() {
+    std::unordered_map<uint32_t, struct task_info> retval;
+    std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(PROC_DIR), closedir);
+    CHECK(dir != NULL);
+    struct dirent* dp;
+
+    for (;;) {
+        if ((dp = readdir(dir.get())) == NULL) break;
+        if (!is_pid(dp->d_name)) continue;
+
+        uint32_t pid = atol(dp->d_name);
+        struct task_info info;
+        if (parse_task_info(pid, &info)) {
+            retval[pid] = info;
+        }
+    }
+    return retval;
+}
+
+static void add_task_info(struct task_info* src, struct task_info* dst) {
+    CHECK(strcmp(src->cmd, dst->cmd) == 0);
+
+    dst->pid = 0;
+    dst->rchar += src->rchar;
+    dst->wchar += src->wchar;
+    dst->syscr += src->syscr;
+    dst->syscw += src->syscw;
+    dst->read_bytes += src->read_bytes;
+    dst->write_bytes += src->write_bytes;
+    dst->cancelled_write_bytes += src->cancelled_write_bytes;
+    dst->starttime = 0;
+}
+
+void tasks_t::update_running_tasks(void) {
+    std::unordered_map<uint32_t, struct task_info> tasks_latest = get_running_tasks();
+    std::unordered_map<std::string, struct task_info> tasks_old = mOld;
+
+    for (auto t : mRunning) {
+        uint32_t pid = t.first;
+        // old task on mRunning still exist on tasks_latest
+        if (tasks_latest.find(pid) != tasks_latest.end() &&
+                tasks_latest[pid].starttime == t.second.starttime) {
+            continue;
+        } else {
+            // This branch will handle 2 cases:
+            // - Task get killed between the 2 samplings
+            // - Task get killed and its pid is reused
+            std::string cmd = t.second.cmd;
+            struct task_info info = t.second;
+
+            if (tasks_old.find(cmd) == tasks_old.end()) {
+                tasks_old[cmd] = info;
+            } else {
+                add_task_info(&info, &tasks_old[cmd]);
+            }
+        }
+    }
+    { // update critical area
+        // this is really fast!
+        std::unique_ptr<lock_t> lock(new lock_t(&mSem));
+        mRunning = tasks_latest;
+        mOld = tasks_old;
+    }
+
+}
+
+std::vector<struct task_info> tasks_t::get_tasks(void) {
+    std::unique_ptr<lock_t> lock(new lock_t(&mSem));
+    std::unordered_map<std::string, struct task_info> tasks_map = mOld;
+
+    for (auto i : mRunning) {
+        std::string cmd = i.second.cmd;
+        if (tasks_map.find(cmd) == tasks_map.end()) {
+            tasks_map[cmd] = i.second;
+        } else {
+            add_task_info(&i.second, &tasks_map[cmd]);
+        }
+    }
+
+    std::vector<struct task_info> retval(tasks_map.size());
+    int idx = 0;
+    for (auto i : tasks_map) {
+        retval[idx++]  = i.second;
+    }
+
+    return retval;
+}
+
+void sort_running_tasks_info(std::vector<struct task_info> &tasks) {
+    std::sort(tasks.begin(), tasks.end(), cmp_task_info);
+}
+
+/* Logging functions */
+void log_console_running_tasks_info(std::vector<struct task_info> tasks) {
+// Sample Output:
+//       Application           Read          Write           Read          Write           Read          Write      Cancelled
+//              Name     Characters     Characters       Syscalls       Syscalls          Bytes          Bytes     Writebytes
+//        ----------     ----------     ----------     ----------     ----------     ----------     ----------     ----------
+//          zygote64       37688308        3388467           7607           4363      314519552        5373952           8192
+//     system_server       95874193        2216913          74613          52257      213078016        7237632          16384
+//            zygote         506279        1726194            921            263      128114688        1765376              0
+//  /vendor/bin/qcks       75415632       75154382          21672          25036       63627264       29974528       10485760
+//             /init       86658523        5107871          82113           8633       91015168        1245184              0
+
+    // Title
+    printf("                                       Application           Read          Write           Read          Write           Read          Write      Cancelled\n"
+           "                                              Name     Characters     Characters       Syscalls       Syscalls          Bytes          Bytes     Writebytes\n"
+           "                                        ----------     ----------     ----------     ----------     ----------     ----------     ----------     ----------\n");
+
+    for (struct task_info task : tasks) {
+        printf("%50s%15ju%15ju%15ju%15ju%15ju%15ju%15ju\n",
+            task.cmd, task.rchar, task.wchar, task.syscr, task.syscw,
+            task.read_bytes, task.write_bytes, task.cancelled_write_bytes);
+    }
+    fflush(stdout);
+}
+
+void log_kernel_disk_stats(struct disk_stats* stats, const char* type) {
+    // skip if the input structure are all zeros
+    if (stats == NULL) return;
+    struct disk_stats zero_cmp;
+    memset(&zero_cmp, 0, sizeof(zero_cmp));
+    if (memcmp(&zero_cmp, stats, sizeof(struct disk_stats)) == 0) return;
+
+    if (fd_dmesg >= 0) {
+        std::string info_message = android::base::StringPrintf(
+            "%s diskstats %s: %ju %ju %ju %ju %ju %ju %ju %ju %ju %ju %.1f %ju %ju\n",
+             kmsg_info_prefix, type, stats->start_time, stats->end_time,
+             stats->read_ios, stats->read_merges,
+             stats->read_sectors, stats->read_ticks,
+             stats->write_ios, stats->write_merges,
+             stats->write_sectors, stats->write_ticks,
+             stats->io_avg, stats->io_ticks,
+             stats->io_in_queue);
+
+        write(fd_dmesg, info_message.c_str(), info_message.length());
+    }
+}
+
+void log_kernel_disk_perf(struct disk_perf* perf, const char* type) {
+    // skip if the input structure are all zeros
+    if (perf == NULL) return;
+    struct disk_perf zero_cmp;
+    memset(&zero_cmp, 0, sizeof(zero_cmp));
+    if (memcmp(&zero_cmp, perf, sizeof(struct disk_perf)) == 0) return;
+
+    if (fd_dmesg >= 0) {
+        std::string info_message = android::base::StringPrintf(
+            "%s perf(ios) %s rd:%luKB/s(%lu/s) wr:%luKB/s(%lu/s) q:%lu\n",
+            kmsg_info_prefix, type,
+            (unsigned long)perf->read_perf, (unsigned long)perf->read_ios,
+            (unsigned long)perf->write_perf, (unsigned long)perf->write_ios,
+            (unsigned long)perf->queue);
+
+        write(fd_dmesg, info_message.c_str(), info_message.length());
+    }
+}
+
+void log_kernel_emmc_info(struct emmc_info* info) {
+    // skip if the input structure are all zeros
+    if (info == NULL) return;
+    struct emmc_info zero_cmp;
+    memset(&zero_cmp, 0, sizeof(zero_cmp));
+    if (memcmp(&zero_cmp, info, sizeof(struct emmc_info)) == 0) return;
+
+    if (fd_dmesg >= 0) {
+        std::string info_message = android::base::StringPrintf(
+            "%s MMC %s eol:%d, lifetime typA:%d, typB:%d\n",
+            kmsg_info_prefix, info->mmc_ver, info->eol, info->lifetime_a, info->lifetime_b);
+
+        write(fd_dmesg, info_message.c_str(), info_message.length());
+    }
+}
+
+void log_event_disk_stats(struct disk_stats* stats, const char* type) {
+    // skip if the input structure are all zeros
+    if (stats == NULL) return;
+    struct disk_stats zero_cmp;
+    memset(&zero_cmp, 0, sizeof(zero_cmp));
+    // skip event logging diskstats when it is zero increment (all first 11 entries are zero)
+    if (memcmp(&zero_cmp, stats, sizeof(uint64_t) * DISK_STATS_SIZE) == 0) return;
+
+    // Construct eventlog list
+    android_log_context ctx = create_android_logger(EVENTLOGTAG_DISKSTATS);
+
+    android_log_write_string8(ctx, type);
+    android_log_write_int64(ctx, stats->start_time);
+    android_log_write_int64(ctx, stats->end_time);
+    android_log_write_int64(ctx, stats->read_ios);
+    android_log_write_int64(ctx, stats->read_merges);
+    android_log_write_int64(ctx, stats->read_sectors);
+    android_log_write_int64(ctx, stats->read_ticks);
+    android_log_write_int64(ctx, stats->write_ios);
+    android_log_write_int64(ctx, stats->write_merges);
+    android_log_write_int64(ctx, stats->write_sectors);
+    android_log_write_int64(ctx, stats->write_ticks);
+    android_log_write_int64(ctx, (uint64_t)stats->io_avg);
+    android_log_write_int64(ctx, stats->io_ticks);
+    android_log_write_int64(ctx, stats->io_in_queue);
+
+    android_log_write_list(ctx, LOG_ID_EVENTS);
+    android_log_destroy(&ctx);
+}
+
+void log_event_emmc_info(struct emmc_info* info) {
+    // skip if the input structure are all zeros
+    if (info == NULL) return;
+    struct emmc_info zero_cmp;
+    memset(&zero_cmp, 0, sizeof(zero_cmp));
+    if (memcmp(&zero_cmp, info, sizeof(struct emmc_info)) == 0) return;
+
+    android_log_context ctx = create_android_logger(EVENTLOGTAG_EMMCINFO);
+
+    android_log_write_string8(ctx, info->mmc_ver);
+    android_log_write_int32(ctx, info->eol);
+    android_log_write_int32(ctx, info->lifetime_a);
+    android_log_write_int32(ctx, info->lifetime_b);
+
+    android_log_write_list(ctx, LOG_ID_EVENTS);
+    android_log_destroy(&ctx);
+}
diff --git a/storaged/tests/Android.mk b/storaged/tests/Android.mk
new file mode 100644
index 0000000..4a0e45c
--- /dev/null
+++ b/storaged/tests/Android.mk
@@ -0,0 +1,45 @@
+#
+# Copyright (C) 2014 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.
+#
+
+LOCAL_PATH := $(call my-dir)
+
+test_module_prefix := storaged-
+test_tags := tests
+
+# -----------------------------------------------------------------------------
+# Unit tests.
+# -----------------------------------------------------------------------------
+
+test_c_flags := \
+    -fstack-protector-all \
+    -g \
+    -Wall -Wextra \
+    -Werror \
+    -fno-builtin \
+
+test_src_files := \
+    storaged_test.cpp \
+
+# Build tests for the logger. Run with:
+#   adb shell /data/nativetest/storaged-unit-tests/storaged-unit-tests
+include $(CLEAR_VARS)
+LOCAL_MODULE := $(test_module_prefix)unit-tests
+LOCAL_MODULE_TAGS := $(test_tags)
+LOCAL_CFLAGS += $(test_c_flags)
+LOCAL_STATIC_LIBRARIES := libstoraged
+LOCAL_SHARED_LIBRARIES := libbase libcutils liblog
+LOCAL_SRC_FILES := $(test_src_files)
+include $(BUILD_NATIVE_TEST)
diff --git a/storaged/tests/storaged_test.cpp b/storaged/tests/storaged_test.cpp
new file mode 100644
index 0000000..4ca9839
--- /dev/null
+++ b/storaged/tests/storaged_test.cpp
@@ -0,0 +1,587 @@
+/*
+ * Copyright (C) 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 <deque>
+#include <fcntl.h>
+#include <random>
+#include <string.h>
+#include <stdio.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include <gtest/gtest.h>
+//#include <private/android_logger.h>
+
+#include <storaged.h>               // data structures
+#include <storaged_utils.h>         // functions to test
+
+#define MMC_DISK_STATS_PATH "/sys/block/mmcblk0/stat"
+#define SDA_DISK_STATS_PATH "/sys/block/sda/stat"
+#define EMMC_EXT_CSD_PATH "/d/mmc0/mmc0:0001/ext_csd"
+#define INIT_TASK_IO_PATH "/proc/1/io"
+
+static void pause(uint32_t sec) {
+    const char* path = "/cache/test";
+    int fd = open(path, O_WRONLY | O_CREAT);
+    ASSERT_LT(-1, fd);
+    char buffer[2048];
+    memset(buffer, 1, sizeof(buffer));
+    int loop_size = 100;
+    for (int i = 0; i < loop_size; ++i) {
+        ASSERT_EQ(2048, write(fd, buffer, sizeof(buffer)));
+    }
+    fsync(fd);
+    close(fd);
+
+    fd = open(path, O_RDONLY);
+    ASSERT_LT(-1, fd);
+    for (int i = 0; i < loop_size; ++i) {
+        ASSERT_EQ(2048, read(fd, buffer, sizeof(buffer)));
+    }
+    close(fd);
+
+    sleep(sec);
+}
+
+// the return values of the tested functions should be the expected ones
+const char* DISK_STATS_PATH;
+TEST(storaged_test, retvals) {
+    struct disk_stats stats;
+    struct emmc_info info;
+    memset(&stats, 0, sizeof(struct disk_stats));
+    memset(&info, 0, sizeof(struct emmc_info));
+
+    int emmc_fd = open(EMMC_EXT_CSD_PATH, O_RDONLY);
+    if (emmc_fd >= 0) {
+        EXPECT_TRUE(parse_emmc_ecsd(emmc_fd, &info));
+    }
+
+    if (access(MMC_DISK_STATS_PATH, R_OK) >= 0) {
+        DISK_STATS_PATH = MMC_DISK_STATS_PATH;
+    } else if (access(SDA_DISK_STATS_PATH, R_OK) >= 0) {
+        DISK_STATS_PATH = SDA_DISK_STATS_PATH;
+    } else {
+        return;
+    }
+
+    EXPECT_TRUE(parse_disk_stats(DISK_STATS_PATH, &stats));
+
+    struct disk_stats old_stats;
+    memset(&old_stats, 0, sizeof(struct disk_stats));
+    old_stats = stats;
+
+    const char wrong_path[] = "/this/is/wrong";
+    EXPECT_FALSE(parse_disk_stats(wrong_path, &stats));
+
+    // reading a wrong path should not damage the output structure
+    EXPECT_EQ(0, memcmp(&stats, &old_stats, sizeof(disk_stats)));
+}
+
+TEST(storaged_test, disk_stats) {
+    struct disk_stats stats;
+    memset(&stats, 0, sizeof(struct disk_stats));
+
+    ASSERT_TRUE(parse_disk_stats(DISK_STATS_PATH, &stats));
+
+    // every entry of stats (except io_in_flight) should all be greater than 0
+    for (uint i = 0; i < DISK_STATS_SIZE; ++i) {
+        if (i == 8) continue; // skip io_in_flight which can be 0
+        EXPECT_LT((uint64_t)0, *((uint64_t*)&stats + i));
+    }
+
+    // accumulation of the increments should be the same with the overall increment
+    struct disk_stats base, tmp, curr, acc, inc[5];
+    memset(&base, 0, sizeof(struct disk_stats));
+    memset(&tmp, 0, sizeof(struct disk_stats));
+    memset(&acc, 0, sizeof(struct disk_stats));
+
+    for (uint i = 0; i < 5; ++i) {
+        ASSERT_TRUE(parse_disk_stats(DISK_STATS_PATH, &curr));
+        if (i == 0) {
+            base = curr;
+            tmp = curr;
+            sleep(5);
+            continue;
+        }
+        inc[i] = get_inc_disk_stats(&tmp, &curr);
+        add_disk_stats(&inc[i], &acc);
+        tmp = curr;
+        pause(5);
+    }
+    struct disk_stats overall_inc;
+    memset(&overall_inc, 0, sizeof(disk_stats));
+    overall_inc= get_inc_disk_stats(&base, &curr);
+
+    for (uint i = 0; i < DISK_STATS_SIZE; ++i) {
+        if (i == 8) continue; // skip io_in_flight which can be 0
+        EXPECT_EQ(*((uint64_t*)&overall_inc + i), *((uint64_t*)&acc + i));
+    }
+}
+
+TEST(storaged_test, emmc_info) {
+    struct emmc_info info, void_info;
+    memset(&info, 0, sizeof(struct emmc_info));
+    memset(&void_info, 0, sizeof(struct emmc_info));
+
+    if (access(EMMC_EXT_CSD_PATH, R_OK) >= 0) {
+        int emmc_fd = open(EMMC_EXT_CSD_PATH, O_RDONLY);
+        ASSERT_GE(emmc_fd, 0);
+        ASSERT_TRUE(parse_emmc_ecsd(emmc_fd, &info));
+        // parse_emmc_ecsd() should put something in info.
+        EXPECT_NE(0, memcmp(&void_info, &info, sizeof(struct emmc_info)));
+    }
+}
+
+TEST(storaged_test, task_info) {
+    // parse_task_info should read something other than 0 from /proc/1/*
+    struct task_info task_info;
+    memset(&task_info, 0, sizeof(task_info));
+
+    if (!parse_task_info(1, &task_info)) return;
+
+    EXPECT_EQ((uint32_t)1, task_info.pid);
+    EXPECT_LT((uint64_t)0, task_info.rchar);
+    EXPECT_LT((uint64_t)0, task_info.wchar);
+    EXPECT_LT((uint64_t)0, task_info.syscr);
+    EXPECT_LT((uint64_t)0, task_info.syscw);
+    EXPECT_LT((uint64_t)0, task_info.read_bytes);
+    EXPECT_LT((uint64_t)0, task_info.write_bytes);
+    // cancelled_write_bytes of init could be 0, there is no need to test
+    EXPECT_LE((uint64_t)0, task_info.starttime);
+    EXPECT_NE((char*)NULL, strstr(task_info.cmd, "init"));
+
+    // Entries in /proc/1/io should be increasing through time
+    struct task_info task_old, task_new;
+    memset(&task_old, 0, sizeof(task_old));
+    memset(&task_new, 0, sizeof(task_new));
+
+    // parse_task_info should succeed at this point
+    ASSERT_TRUE(parse_task_info(1, &task_old));
+    sleep(1);
+    ASSERT_TRUE(parse_task_info(1, &task_new));
+
+    EXPECT_EQ(task_old.pid, task_new.pid);
+    EXPECT_LE(task_old.rchar, task_new.rchar);
+    EXPECT_LE(task_old.wchar, task_new.wchar);
+    EXPECT_LE(task_old.syscr, task_new.syscr);
+    EXPECT_LE(task_old.syscw, task_new.syscw);
+    EXPECT_LE(task_old.read_bytes, task_new.read_bytes);
+    EXPECT_LE(task_old.write_bytes, task_new.write_bytes);
+    EXPECT_LE(task_old.cancelled_write_bytes, task_new.cancelled_write_bytes);
+    EXPECT_EQ(task_old.starttime, task_new.starttime);
+    EXPECT_EQ(0, strcmp(task_old.cmd, task_new.cmd));
+}
+
+static double mean(std::deque<uint32_t> nums) {
+    double sum = 0.0;
+    for (uint32_t i : nums) {
+    sum += i;
+    }
+    return sum / nums.size();
+}
+
+static double standard_deviation(std::deque<uint32_t> nums) {
+    double sum = 0.0;
+    double avg = mean(nums);
+    for (uint32_t i : nums) {
+    sum += ((double)i - avg) * ((double)i - avg);
+    }
+    return sqrt(sum / nums.size());
+}
+
+TEST(storaged_test, stream_stats) {
+    // 100 random numbers
+    std::vector<uint32_t> data = {8147,9058,1270,9134,6324,975,2785,5469,9575,9649,1576,9706,9572,4854,8003,1419,4218,9157,7922,9595,6557,357,8491,9340,6787,7577,7431,3922,6555,1712,7060,318,2769,462,971,8235,6948,3171,9502,344,4387,3816,7655,7952,1869,4898,4456,6463,7094,7547,2760,6797,6551,1626,1190,4984,9597,3404,5853,2238,7513,2551,5060,6991,8909,9593,5472,1386,1493,2575,8407,2543,8143,2435,9293,3500,1966,2511,6160,4733,3517,8308,5853,5497,9172,2858,7572,7537,3804,5678,759,540,5308,7792,9340,1299,5688,4694,119,3371};
+    std::deque<uint32_t> test_data;
+    stream_stats sstats;
+    for (uint32_t i : data) {
+        test_data.push_back(i);
+        sstats.add(i);
+
+        EXPECT_EQ((int)standard_deviation(test_data), (int)sstats.get_std());
+        EXPECT_EQ((int)mean(test_data), (int)sstats.get_mean());
+    }
+
+    for (uint32_t i : data) {
+        test_data.pop_front();
+        sstats.evict(i);
+
+        EXPECT_EQ((int)standard_deviation(test_data), (int)sstats.get_std());
+        EXPECT_EQ((int)mean(test_data), (int)sstats.get_mean());
+    }
+
+    // some real data
+    std::vector<uint32_t> another_data = {113875,81620,103145,28327,86855,207414,96526,52567,28553,250311};
+    test_data.clear();
+    uint32_t window_size = 2;
+    uint32_t idx;
+    stream_stats sstats1;
+    for (idx = 0; idx < window_size; ++idx) {
+        test_data.push_back(another_data[idx]);
+        sstats1.add(another_data[idx]);
+    }
+    EXPECT_EQ((int)standard_deviation(test_data), (int)sstats1.get_std());
+    EXPECT_EQ((int)mean(test_data), (int)sstats1.get_mean());
+    for (;idx < another_data.size(); ++idx) {
+        test_data.pop_front();
+        sstats1.evict(another_data[idx - window_size]);
+        test_data.push_back(another_data[idx]);
+        sstats1.add(another_data[idx]);
+        EXPECT_EQ((int)standard_deviation(test_data), (int)sstats1.get_std());
+        EXPECT_EQ((int)mean(test_data), (int)sstats1.get_mean());
+    }
+}
+
+static void expect_increasing(struct task_info told, struct task_info tnew) {
+    ASSERT_EQ(told.pid, tnew.pid);
+    ASSERT_EQ(told.starttime, tnew.starttime);
+    ASSERT_EQ(strcmp(told.cmd, tnew.cmd), 0);
+
+    EXPECT_LE(told.rchar, tnew.rchar);
+    EXPECT_LE(told.wchar, tnew.wchar);
+    EXPECT_LE(told.syscr, tnew.syscr);
+    EXPECT_LE(told.syscw, tnew.syscw);
+    EXPECT_LE(told.read_bytes, tnew.read_bytes);
+    EXPECT_LE(told.write_bytes, tnew.write_bytes);
+    EXPECT_LE(told.cancelled_write_bytes, tnew.cancelled_write_bytes);
+}
+
+static void expect_equal(struct task_info told, struct task_info tnew) {
+    ASSERT_EQ(told.pid, tnew.pid);
+    ASSERT_EQ(told.starttime, tnew.starttime);
+    ASSERT_EQ(strcmp(told.cmd, tnew.cmd), 0);
+
+    EXPECT_EQ(told.rchar, tnew.rchar);
+    EXPECT_EQ(told.wchar, tnew.wchar);
+    EXPECT_EQ(told.syscr, tnew.syscr);
+    EXPECT_EQ(told.syscw, tnew.syscw);
+    EXPECT_EQ(told.read_bytes, tnew.read_bytes);
+    EXPECT_EQ(told.write_bytes, tnew.write_bytes);
+    EXPECT_EQ(told.cancelled_write_bytes, tnew.cancelled_write_bytes);
+}
+
+static std::set<uint32_t> find_overlap(std::unordered_map<uint32_t, struct task_info> t1,
+                                       std::unordered_map<uint32_t, struct task_info> t2) {
+    std::set<uint32_t> retval;
+    for (auto i : t1) {
+        if (t2.find(i.first) != t2.end()) {
+            retval.insert(i.first);
+        }
+    }
+
+    return retval;
+}
+
+static std::set<std::string> find_overlap(std::unordered_map<std::string, struct task_info> t1,
+                                          std::unordered_map<std::string, struct task_info> t2) {
+    std::set<std::string> retval;
+    for (auto i : t1) {
+        if (t2.find(i.first) != t2.end()) {
+            retval.insert(i.first);
+        }
+    }
+
+    return retval;
+}
+
+static bool cmp_app_name(struct task_info i, struct task_info j) {
+    return strcmp(i.cmd, j.cmd) > 0;
+}
+
+static void expect_match(std::vector<struct task_info> v1, std::vector<struct task_info> v2) {
+    ASSERT_EQ(v1.size(), v2.size());
+    std::sort(v1.begin(), v1.end(), cmp_app_name);
+    std::sort(v2.begin(), v2.end(), cmp_app_name);
+
+    for (uint i = 0; i < v1.size(); ++i) {
+        expect_equal(v1[i], v2[i]);
+    }
+}
+
+static void add_task_info(struct task_info* src, struct task_info* dst) {
+    ASSERT_EQ(0, strcmp(src->cmd, dst->cmd));
+
+    dst->pid = 0;
+    dst->rchar += src->rchar;
+    dst->wchar += src->wchar;
+    dst->syscr += src->syscr;
+    dst->syscw += src->syscw;
+    dst->read_bytes += src->read_bytes;
+    dst->write_bytes += src->write_bytes;
+    dst->cancelled_write_bytes += src->cancelled_write_bytes;
+    dst->starttime = 0;
+}
+
+static std::vector<struct task_info>
+categorize_tasks(std::unordered_map<uint32_t, struct task_info> tasks) {
+    std::unordered_map<std::string, struct task_info> tasks_cmd;
+    for (auto i : tasks) {
+        std::string cmd = i.second.cmd;
+        if (tasks_cmd.find(cmd) == tasks_cmd.end()) {
+            tasks_cmd[cmd] = i.second;
+        } else {
+            add_task_info(&i.second, &tasks_cmd[cmd]);
+        }
+    }
+
+    std::vector<struct task_info> retval(tasks_cmd.size());
+    int cnt = 0;
+    for (auto i : tasks_cmd) {
+        retval[cnt++] = i.second;
+    }
+
+    return retval;
+}
+
+#define TEST_LOOPS 20
+TEST(storaged_test, tasks_t) {
+    // pass this test if /proc/[pid]/io is not readable
+    const char* test_paths[] = {"/proc/1/io", "/proc/1/comm", "/proc/1/cmdline", "/proc/1/stat"};
+    for (uint i = 0; i < sizeof(test_paths) / sizeof(const char*); ++i) {
+        if (access(test_paths[i], R_OK) < 0) return;
+    }
+
+    tasks_t tasks;
+    EXPECT_EQ((uint32_t)0, tasks.mRunning.size());
+    EXPECT_EQ((uint32_t)0, tasks.mOld.size());
+
+    tasks.update_running_tasks();
+
+    std::unordered_map<uint32_t, struct task_info> prev_running = tasks.mRunning;
+    std::unordered_map<std::string, struct task_info> prev_old = tasks.mOld;
+
+    // hashmap maintaining
+    std::unordered_map<uint32_t, struct task_info> tasks_pid = tasks.mRunning;
+
+    // get_running_tasks() should return something other than a null map
+    std::unordered_map<uint32_t, struct task_info> test = tasks.get_running_tasks();
+    EXPECT_LE((uint32_t)1, test.size());
+
+    for (int i = 0; i < TEST_LOOPS; ++i) {
+        tasks.update_running_tasks();
+
+        std::set<uint32_t> overlap_running = find_overlap(prev_running, tasks.mRunning);
+        std::set<std::string> overlap_old = find_overlap(prev_old, tasks.mOld);
+
+        // overlap_running should capture init(pid == 1), since init never get killed
+        EXPECT_LE((uint32_t)1, overlap_running.size());
+        EXPECT_NE(overlap_running.find((uint32_t)1), overlap_running.end());
+        // overlap_old should never capture init, since init never get killed
+        EXPECT_EQ(overlap_old.find("init"), overlap_old.end());
+
+        // overlapping entries in previous and current running-tasks map should have increasing contents
+        for (uint32_t i : overlap_running) {
+            expect_increasing(prev_running[i], tasks.mRunning[i]);
+        }
+
+        // overlapping entries in previous and current killed-tasks map should have increasing contents
+        // and the map size should also be increasing
+        for (std::string i : overlap_old) {
+            expect_increasing(prev_old[i], tasks.mOld[i]);
+        }
+        EXPECT_LE(prev_old.size(), tasks.mRunning.size());
+
+        // update app name & tasks_pid
+        for (auto i : tasks.mRunning) {
+            // test will fail if the pid got wrapped
+            if (tasks_pid.find(i.first) != tasks_pid.end()) {
+                expect_increasing(tasks_pid[i.first], i.second);
+                tasks_pid[i.first] = i.second;
+            } else {
+                tasks_pid[i.first] = i.second;
+            }
+        }
+
+        // get maintained tasks
+        std::vector<struct task_info> test_tasks = categorize_tasks(tasks_pid);
+        std::vector<struct task_info> real_tasks = tasks.get_tasks();
+
+        expect_match(test_tasks, real_tasks);
+
+        prev_running = tasks.mRunning;
+        prev_old = tasks.mOld;
+
+        pause(5);
+    }
+}
+
+static struct disk_perf disk_perf_multiply(struct disk_perf perf, double mul) {
+    struct disk_perf retval;
+    retval.read_perf = (double)perf.read_perf * mul;
+    retval.read_ios = (double)perf.read_ios * mul;
+    retval.write_perf = (double)perf.write_perf * mul;
+    retval.write_ios = (double)perf.write_ios * mul;
+    retval.queue = (double)perf.queue * mul;
+
+    return retval;
+}
+
+static struct disk_stats disk_stats_add(struct disk_stats stats1, struct disk_stats stats2) {
+    struct disk_stats retval;
+    retval.read_ios = stats1.read_ios + stats2.read_ios;
+    retval.read_merges = stats1.read_merges + stats2.read_merges;
+    retval.read_sectors = stats1.read_sectors + stats2.read_sectors;
+    retval.read_ticks = stats1.read_ticks + stats2.read_ticks;
+    retval.write_ios = stats1.write_ios + stats2.write_ios;
+    retval.write_merges = stats1.write_merges + stats2.write_merges;
+    retval.write_sectors = stats1.write_sectors + stats2.write_sectors;
+    retval.write_ticks = stats1.write_ticks + stats2.write_ticks;
+    retval.io_in_flight = stats1.io_in_flight + stats2.io_in_flight;
+    retval.io_ticks = stats1.io_ticks + stats2.io_ticks;
+    retval.io_in_queue = stats1.io_in_queue + stats2.io_in_queue;
+    retval.end_time = stats1.end_time + stats2.end_time;
+
+    return retval;
+}
+
+TEST(storaged_test, disk_stats_monitor) {
+    // asserting that there is one file for diskstats
+    ASSERT_TRUE(access(MMC_DISK_STATS_PATH, R_OK) >= 0 || access(SDA_DISK_STATS_PATH, R_OK) >= 0);
+    // testing if detect() will return the right value
+    disk_stats_monitor dsm_detect;
+    // feed monitor with constant perf data for io perf baseline
+    // using constant perf is reasonable since the functionality of stream_stats
+    // has already been tested
+    struct disk_perf norm_perf = {
+        .read_perf = 10 * 1024,
+        .read_ios = 50,
+        .write_perf = 5 * 1024,
+        .write_ios = 25,
+        .queue = 5
+    };
+
+    std::random_device rd;
+    std::mt19937 gen(rd());
+    std::uniform_real_distribution<> rand(0.8, 1.2);
+
+    for (uint i = 0; i < dsm_detect.mWindow; ++i) {
+        struct disk_perf perf = disk_perf_multiply(norm_perf, rand(gen));
+
+        dsm_detect.add(&perf);
+        dsm_detect.mBuffer.push(perf);
+        EXPECT_EQ(dsm_detect.mBuffer.size(), (uint64_t)i + 1);
+    }
+
+    dsm_detect.mValid = true;
+    dsm_detect.update_mean();
+    dsm_detect.update_std();
+
+    for (double i = 0; i < 2 * dsm_detect.mSigma; i += 0.5) {
+        struct disk_perf test_perf;
+        struct disk_perf test_mean = dsm_detect.mMean;
+        struct disk_perf test_std = dsm_detect.mStd;
+
+        test_perf.read_perf = (double)test_mean.read_perf - i * test_std.read_perf;
+        test_perf.read_ios = (double)test_mean.read_ios - i * test_std.read_ios;
+        test_perf.write_perf = (double)test_mean.write_perf - i * test_std.write_perf;
+        test_perf.write_ios = (double)test_mean.write_ios - i * test_std.write_ios;
+        test_perf.queue = (double)test_mean.queue + i * test_std.queue;
+
+        EXPECT_EQ((i > dsm_detect.mSigma), dsm_detect.detect(&test_perf));
+    }
+
+    // testing if stalled disk_stats can be correctly accumulated in the monitor
+    disk_stats_monitor dsm_acc;
+    struct disk_stats norm_inc = {
+        .read_ios = 200,
+        .read_merges = 0,
+        .read_sectors = 200,
+        .read_ticks = 200,
+        .write_ios = 100,
+        .write_merges = 0,
+        .write_sectors = 100,
+        .write_ticks = 100,
+        .io_in_flight = 0,
+        .io_ticks = 600,
+        .io_in_queue = 300,
+        .start_time = 0,
+        .end_time = 100,
+        .counter = 0,
+        .io_avg = 0
+    };
+
+    struct disk_stats stall_inc = {
+        .read_ios = 200,
+        .read_merges = 0,
+        .read_sectors = 20,
+        .read_ticks = 200,
+        .write_ios = 100,
+        .write_merges = 0,
+        .write_sectors = 10,
+        .write_ticks = 100,
+        .io_in_flight = 0,
+        .io_ticks = 600,
+        .io_in_queue = 1200,
+        .start_time = 0,
+        .end_time = 100,
+        .counter = 0,
+        .io_avg = 0
+    };
+
+    struct disk_stats stats_base;
+    memset(&stats_base, 0, sizeof(stats_base));
+
+    int loop_size = 100;
+    for (int i = 0; i < loop_size; ++i) {
+        stats_base = disk_stats_add(stats_base, norm_inc);
+        dsm_acc.update(&stats_base);
+        EXPECT_EQ(dsm_acc.mValid, (uint32_t)(i + 1) >= dsm_acc.mWindow);
+        EXPECT_FALSE(dsm_acc.mStall);
+    }
+
+    stats_base = disk_stats_add(stats_base, stall_inc);
+    dsm_acc.update(&stats_base);
+    EXPECT_TRUE(dsm_acc.mValid);
+    EXPECT_TRUE(dsm_acc.mStall);
+
+    for (int i = 0; i < 10; ++i) {
+        stats_base = disk_stats_add(stats_base, norm_inc);
+        dsm_acc.update(&stats_base);
+        EXPECT_TRUE(dsm_acc.mValid);
+        EXPECT_FALSE(dsm_acc.mStall);
+    }
+}
+
+static void expect_increasing(struct disk_stats stats1, struct disk_stats stats2) {
+    EXPECT_LE(stats1.read_ios, stats2.read_ios);
+    EXPECT_LE(stats1.read_merges, stats2.read_merges);
+    EXPECT_LE(stats1.read_sectors, stats2.read_sectors);
+    EXPECT_LE(stats1.read_ticks, stats2.read_ticks);
+
+    EXPECT_LE(stats1.write_ios, stats2.write_ios);
+    EXPECT_LE(stats1.write_merges, stats2.write_merges);
+    EXPECT_LE(stats1.write_sectors, stats2.write_sectors);
+    EXPECT_LE(stats1.write_ticks, stats2.write_ticks);
+
+    EXPECT_LE(stats1.io_ticks, stats2.io_ticks);
+    EXPECT_LE(stats1.io_in_queue, stats2.io_in_queue);
+}
+
+TEST(storaged_test, disk_stats_publisher) {
+    // asserting that there is one file for diskstats
+    ASSERT_TRUE(access(MMC_DISK_STATS_PATH, R_OK) >= 0 || access(SDA_DISK_STATS_PATH, R_OK) >= 0);
+    disk_stats_publisher dsp;
+    struct disk_stats prev;
+    memset(&prev, 0, sizeof(prev));
+
+    for (int i = 0; i < TEST_LOOPS; ++i) {
+        dsp.update();
+        expect_increasing(prev, dsp.mPrevious);
+        prev = dsp.mPrevious;
+        pause(10);
+    }
+}
+