Basic IPMI User Management Support

Squashed commit containing Basic User Management
implementation

Unit Test:
1. Verified both Host & NetIpmid works fine.
2. Verified user related command responses

commit b46b869c0a3958a572b976b3bbaf6b5f33673778
Author: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>
Date:   Tue Aug 7 15:30:32 2018 +0530

    Fix static objects to directly link user layer

    User layer library has to be directly linked with netipmid
    in order to be used in RAKP commands. Hence user layer
    library should not initialize the static bus objects in file
    scope, as ipmid_get_sd_bus_connection() won't be available
    during this time. Hence moved it under function scope and
    initialize it later.

    Unit test:
    Made sure, with this change it is loaded perfectly under
    phosphor-ipmi-host & phosphor-ipmi-net and responding to
    all user commands

    Change-Id: Id3f2e06580ca41b0347176ca33e011bf7b048c6a
    Signed-off-by: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>

commit dc60516c45234379a30ad8b03b1cbe53978faeae
Author: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>
Date:   Tue Aug 7 15:22:37 2018 +0530

    Fix to use proper user index for set user name

    Fix to use proper user index, instead of bailing out
    on first empty index. If user creation is requested on
    random index with previous index empty, then signal
    handler updates the data in first empty index, instead of
    traversing the user list fully. Fix added to mark the first
    free index, and still search for match to skip if found.

    Unit Test:
    Verified that user added in random index shows in that index
    using ipmitool set user name command.

    Change-Id: I30d9b884a5bae98b243ccf8ba7da194ef81355e6
    Signed-off-by: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>

commit 0b9a81a1261b08ea13ad8777d0d80dad937e9972
Author: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>
Date:   Fri Jul 6 15:57:02 2018 +0530

    Converting json store to array for user config

    Addressed comments to convert to array instead of key
    value pair.

    Testing: Performed basic testing of user management commands
    in both host & netipmid, by repeatedly restarting the same.

    Change-Id: I2e51ded3e2299fa196d868213950d96c72886358
    Signed-off-by: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>

commit 182c945657b29acaeb13fc44129e0ed929013e59
Author: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>
Date:   Sat Jun 30 00:07:28 2018 +0530

    Fix D-Bus paths for user management

    Fix D-Bus path as per upstream code in user management

    Change-Id: Idb22bee4365520f3d58e70ff61b02d6f6512d707
    Signed-off-by: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>

commit cd5e22b16f8805dda396311b06994a9e021e97e9
Author: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>
Date:   Thu Jun 28 06:22:27 2018 +0530

    Json format to store user config & cleanup

    Code updated to use json format to store and read
    the user configuration data. Few basic cleanup's
    performed.

    Change-Id: I7005f4f2648ccb8214312982a755ddcc6c33e64d
    Signed-off-by: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>

commit 95ca9a67a4b84df603db0eb6a7024e9e0e5ad342
Author: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>
Date:   Wed May 30 15:16:47 2018 +0530

    Get & Set User Access command implementation

    Get & Set User access command implementation

    Change-Id: I4f7a86de95400387c47ae556127baa1f02a703b2
    Signed-off-by: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>

commit b2dea762362d06b70576dba5f45552d548792cb9
Author: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>
Date:   Fri May 18 23:46:23 2018 +0530

    User layer separation.

    Separated out user commands from the implementation details,
    by creating user layers. App Handler library and netipmid
    will directly rely on this user_layer.so

    Change-Id: Ie7d4b3a5a934e32da73e066a25da4c27485c59c8
    Signed-off-by: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>

commit 63e3113e522ecc7ce6e5aa1c85de4dc9b9a65a7b
Author: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>
Date:   Mon May 7 12:00:06 2018 +0530

    Updated user management ipmi support

    1. Relying on Object Manager & D-Bus properties signal (except
    user rename, for which still relying on user rename signal)
    2. Minor clean-up.

    Change-Id: I594e7823a2c626bb7c88ec54a3ffa89a60b09c65
    Signed-off-by: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>

commit 3e7b774c842917743369569790612d74387c755e
Author: AppaRao Puli <apparao.puli@intel.com>
Date:   Tue Apr 24 22:01:15 2018 +0530

    Synchronize user manager data during ipmi startup

    Synchronizing the user information by reading
    all managed user objects from dbus and checking
    ipmi user data for any update/delete/add users.

    Change-Id: I9e1a62ec9dd186a7276d083a57e679606d635e05
    Signed-off-by: AppaRao Puli <apparao.puli@intel.com>
    Signed-off-by: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>

commit 92298ac0f591d167b0e26b977316a2b136127778
Author: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>
Date:   Tue Apr 24 21:34:08 2018 +0530

    Minor fix: Read user enabled state in signals

    Fixed to read user enabled state in signal handlers.

    Change-Id: I0aa6c4687c16e08d8e304315e85cb65e9dbd346a
    Signed-off-by: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>

commit 8646d2683fc247ce02a0460f9577276eb6e0a581
Author: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>
Date:   Wed Apr 11 22:18:44 2018 +0530

    Signal handler update

    Support added to handle group, privilege
    user rename, enable / disable signal, and
    update the database accordingly.

    Change-Id: Ia33d063715a35814bbe1f9220e9609b800261e33
    Signed-off-by: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>

commit fa411b2c4bbef50175b084889a4829206263ebdb
Author: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>
Date:   Mon Mar 12 23:42:34 2018 +0530

    Add Basic user manager support - IPMI

    Add basic user manager support in IPMI
    Creates user through D-Bus user interface
    and sets password using pam_chauthok().
    Lock & File reload mechanism also implmeneted.
    UserUpdate signal handler support added to update
    user in IPMI, when users are updated through
    different interfaces.

    Change-Id: I1adc538562615109189d7c19dadae0b6a109f4a5
    Signed-off-by: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>

Change-Id: I1adc538562615109189d7c19dadae0b6a109f4a5
Signed-off-by: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>

1 files changed, 1304 insertions, 0 deletions

diff --git a/user_channel/user_mgmt.cpp b/user_channel/user_mgmt.cpp
new file mode 100644
index 0000000..e320e3f
--- /dev/null
+++ b/user_channel/user_mgmt.cpp
@@ -0,0 +1,1304 @@
+/*
+// Copyright (c) 2018 Intel Corporation
+//
+// 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 "user_mgmt.hpp"
+
+#include "apphandler.hpp"
+
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include <boost/interprocess/sync/named_recursive_mutex.hpp>
+#include <boost/interprocess/sync/scoped_lock.hpp>
+#include <cerrno>
+#include <fstream>
+#include <host-ipmid/ipmid-host-cmd.hpp>
+#include <nlohmann/json.hpp>
+#include <phosphor-logging/elog-errors.hpp>
+#include <phosphor-logging/log.hpp>
+#include <regex>
+#include <sdbusplus/bus/match.hpp>
+#include <sdbusplus/server/object.hpp>
+#include <xyz/openbmc_project/Common/error.hpp>
+#include <xyz/openbmc_project/User/Common/error.hpp>
+
+namespace ipmi
+{
+
+// TODO: Move D-Bus & Object Manager related stuff, to common files
+// D-Bus property related
+static constexpr const char* dBusPropertiesInterface =
+    "org.freedesktop.DBus.Properties";
+static constexpr const char* getAllPropertiesMethod = "GetAll";
+static constexpr const char* propertiesChangedSignal = "PropertiesChanged";
+static constexpr const char* setPropertiesMethod = "Set";
+
+// Object Manager related
+static constexpr const char* dBusObjManager =
+    "org.freedesktop.DBus.ObjectManager";
+static constexpr const char* getManagedObjectsMethod = "GetManagedObjects";
+// Object Manager signals
+static constexpr const char* intfAddedSignal = "InterfacesAdded";
+static constexpr const char* intfRemovedSignal = "InterfacesRemoved";
+
+// Object Mapper related
+static constexpr const char* objMapperService =
+    "xyz.openbmc_project.ObjectMapper";
+static constexpr const char* objMapperPath =
+    "/xyz/openbmc_project/object_mapper";
+static constexpr const char* objMapperInterface =
+    "xyz.openbmc_project.ObjectMapper";
+static constexpr const char* getSubTreeMethod = "GetSubTree";
+static constexpr const char* getObjectMethod = "GetObject";
+
+static constexpr const char* ipmiUserMutex = "ipmi_usr_mutex";
+static constexpr const char* ipmiMutexCleanupLockFile =
+    "/var/lib/ipmi/ipmi_usr_mutex_cleanup";
+static constexpr const char* ipmiUserDataFile = "/var/lib/ipmi/ipmi_user.json";
+static constexpr const char* ipmiGrpName = "ipmi";
+static constexpr size_t privNoAccess = 0xF;
+static constexpr size_t privMask = 0xF;
+
+// User manager related
+static constexpr const char* userMgrObjBasePath = "/xyz/openbmc_project/user";
+static constexpr const char* userObjBasePath = "/xyz/openbmc_project/user";
+static constexpr const char* userMgrInterface =
+    "xyz.openbmc_project.User.Manager";
+static constexpr const char* usersInterface =
+    "xyz.openbmc_project.User.Attributes";
+static constexpr const char* deleteUserInterface =
+    "xyz.openbmc_project.Object.Delete";
+
+static constexpr const char* createUserMethod = "CreateUser";
+static constexpr const char* deleteUserMethod = "Delete";
+static constexpr const char* renameUserMethod = "RenameUser";
+// User manager signal memebers
+static constexpr const char* userRenamedSignal = "UserRenamed";
+// Mgr interface properties
+static constexpr const char* allPrivProperty = "AllPrivileges";
+static constexpr const char* allGrpProperty = "AllGroups";
+// User interface properties
+static constexpr const char* userPrivProperty = "UserPrivilege";
+static constexpr const char* userGrpProperty = "UserGroups";
+static constexpr const char* userEnabledProperty = "UserEnabled";
+
+static std::array<std::string, (PRIVILEGE_OEM + 1)> ipmiPrivIndex = {
+    "priv-reserved", // PRIVILEGE_RESERVED - 0
+    "priv-callback", // PRIVILEGE_CALLBACK - 1
+    "priv-user",     // PRIVILEGE_USER - 2
+    "priv-operator", // PRIVILEGE_OPERATOR - 3
+    "priv-admin",    // PRIVILEGE_ADMIN - 4
+    "priv-custom"    // PRIVILEGE_OEM - 5
+};
+
+using namespace phosphor::logging;
+using Json = nlohmann::json;
+
+using PrivAndGroupType =
+    sdbusplus::message::variant<std::string, std::vector<std::string>>;
+
+using NoResource =
+    sdbusplus::xyz::openbmc_project::User::Common::Error::NoResource;
+
+using InternalFailure =
+    sdbusplus::xyz::openbmc_project::Common::Error::InternalFailure;
+
+std::unique_ptr<sdbusplus::bus::match_t> userUpdatedSignal(nullptr);
+std::unique_ptr<sdbusplus::bus::match_t> userMgrRenamedSignal(nullptr);
+std::unique_ptr<sdbusplus::bus::match_t> userPropertiesSignal(nullptr);
+
+// TODO:  Below code can be removed once it is moved to common layer libmiscutil
+std::string getUserService(sdbusplus::bus::bus& bus, const std::string& intf,
+                           const std::string& path)
+{
+    auto mapperCall = bus.new_method_call(objMapperService, objMapperPath,
+                                          objMapperInterface, getObjectMethod);
+
+    mapperCall.append(path);
+    mapperCall.append(std::vector<std::string>({intf}));
+
+    auto mapperResponseMsg = bus.call(mapperCall);
+
+    std::map<std::string, std::vector<std::string>> mapperResponse;
+    mapperResponseMsg.read(mapperResponse);
+
+    if (mapperResponse.begin() == mapperResponse.end())
+    {
+        throw sdbusplus::exception::SdBusError(
+            -EIO, "ERROR in reading the mapper response");
+    }
+
+    return mapperResponse.begin()->first;
+}
+
+void setDbusProperty(sdbusplus::bus::bus& bus, const std::string& service,
+                     const std::string& objPath, const std::string& interface,
+                     const std::string& property,
+                     const DbusUserPropVariant& value)
+{
+    try
+    {
+        auto method =
+            bus.new_method_call(service.c_str(), objPath.c_str(),
+                                dBusPropertiesInterface, setPropertiesMethod);
+        method.append(interface, property, value);
+        bus.call(method);
+    }
+    catch (const sdbusplus::exception::SdBusError& e)
+    {
+        log<level::ERR>("Failed to set property",
+                        entry("PROPERTY=%s", property.c_str()),
+                        entry("PATH=%s", objPath.c_str()),
+                        entry("INTERFACE=%s", interface.c_str()));
+        throw;
+    }
+}
+
+static std::string getUserServiceName()
+{
+    static sdbusplus::bus::bus bus(ipmid_get_sd_bus_connection());
+    static std::string userMgmtService;
+    if (userMgmtService.empty())
+    {
+        try
+        {
+            userMgmtService =
+                ipmi::getUserService(bus, userMgrInterface, userMgrObjBasePath);
+        }
+        catch (const sdbusplus::exception::SdBusError& e)
+        {
+            userMgmtService.clear();
+        }
+    }
+    return userMgmtService;
+}
+
+UserAccess& getUserAccessObject()
+{
+    static UserAccess userAccess;
+    return userAccess;
+}
+
+int getUserNameFromPath(const std::string& path, std::string& userName)
+{
+    static size_t pos = strlen(userObjBasePath) + 1;
+    if (path.find(userObjBasePath) == std::string::npos)
+    {
+        return -EINVAL;
+    }
+    userName.assign(path, pos, path.size());
+    return 0;
+}
+
+void userUpdateHelper(UserAccess& usrAccess, const UserUpdateEvent& userEvent,
+                      const std::string& userName, const std::string& priv,
+                      const bool& enabled, const std::string& newUserName)
+{
+    UsersTbl* userData = usrAccess.getUsersTblPtr();
+    if (userEvent == UserUpdateEvent::userCreated)
+    {
+        if (usrAccess.addUserEntry(userName, priv, enabled) == false)
+        {
+            return;
+        }
+    }
+    else
+    {
+        // user index 0 is reserved, starts with 1
+        size_t usrIndex = 1;
+        for (; usrIndex <= ipmiMaxUsers; ++usrIndex)
+        {
+            std::string curName(
+                reinterpret_cast<char*>(userData->user[usrIndex].userName), 0,
+                ipmiMaxUserName);
+            if (userName == curName)
+            {
+                break; // found the entry
+            }
+        }
+        if (usrIndex > ipmiMaxUsers)
+        {
+            log<level::DEBUG>("User not found for signal",
+                              entry("USER_NAME=%s", userName.c_str()),
+                              entry("USER_EVENT=%d", userEvent));
+            return;
+        }
+        switch (userEvent)
+        {
+            case UserUpdateEvent::userDeleted:
+            {
+                usrAccess.deleteUserIndex(usrIndex);
+                break;
+            }
+            case UserUpdateEvent::userPrivUpdated:
+            {
+                uint8_t userPriv =
+                    static_cast<uint8_t>(
+                        UserAccess::convertToIPMIPrivilege(priv)) &
+                    privMask;
+                // Update all channels privileges, only if it is not equivalent
+                // to getUsrMgmtSyncIndex()
+                if (userData->user[usrIndex]
+                        .userPrivAccess[UserAccess::getUsrMgmtSyncIndex()]
+                        .privilege != userPriv)
+                {
+                    for (size_t chIndex = 0; chIndex < ipmiMaxChannels;
+                         ++chIndex)
+                    {
+                        userData->user[usrIndex]
+                            .userPrivAccess[chIndex]
+                            .privilege = userPriv;
+                    }
+                }
+                break;
+            }
+            case UserUpdateEvent::userRenamed:
+            {
+                std::fill(
+                    static_cast<uint8_t*>(userData->user[usrIndex].userName),
+                    static_cast<uint8_t*>(userData->user[usrIndex].userName) +
+                        sizeof(userData->user[usrIndex].userName),
+                    0);
+                std::strncpy(
+                    reinterpret_cast<char*>(userData->user[usrIndex].userName),
+                    newUserName.c_str(), ipmiMaxUserName);
+                ipmiRenameUserEntryPassword(userName, newUserName);
+                break;
+            }
+            case UserUpdateEvent::userStateUpdated:
+            {
+                userData->user[usrIndex].userEnabled = enabled;
+                break;
+            }
+            default:
+            {
+                log<level::ERR>("Unhandled user event",
+                                entry("USER_EVENT=%d", userEvent));
+                return;
+            }
+        }
+    }
+    usrAccess.writeUserData();
+    log<level::DEBUG>("User event handled successfully",
+                      entry("USER_NAME=%s", userName.c_str()),
+                      entry("USER_EVENT=%d", userEvent));
+
+    return;
+}
+
+void userUpdatedSignalHandler(UserAccess& usrAccess,
+                              sdbusplus::message::message& msg)
+{
+    static sdbusplus::bus::bus bus(ipmid_get_sd_bus_connection());
+    std::string signal = msg.get_member();
+    std::string userName, update, priv, newUserName;
+    std::vector<std::string> groups;
+    bool enabled = false;
+    UserUpdateEvent userEvent = UserUpdateEvent::reservedEvent;
+    if (signal == intfAddedSignal)
+    {
+        DbusUserObjPath objPath;
+        DbusUserObjValue objValue;
+        msg.read(objPath, objValue);
+        getUserNameFromPath(objPath.str, userName);
+        if (usrAccess.getUserObjProperties(objValue, groups, priv, enabled) !=
+            0)
+        {
+            return;
+        }
+        if (std::find(groups.begin(), groups.end(), ipmiGrpName) ==
+            groups.end())
+        {
+            return;
+        }
+        userEvent = UserUpdateEvent::userCreated;
+    }
+    else if (signal == intfRemovedSignal)
+    {
+        DbusUserObjPath objPath;
+        std::vector<std::string> interfaces;
+        msg.read(objPath, interfaces);
+        getUserNameFromPath(objPath.str, userName);
+        userEvent = UserUpdateEvent::userDeleted;
+    }
+    else if (signal == userRenamedSignal)
+    {
+        msg.read(userName, newUserName);
+        userEvent = UserUpdateEvent::userRenamed;
+    }
+    else if (signal == propertiesChangedSignal)
+    {
+        getUserNameFromPath(msg.get_path(), userName);
+    }
+    else
+    {
+        log<level::ERR>("Unknown user update signal",
+                        entry("SIGNAL=%s", signal.c_str()));
+        return;
+    }
+
+    if (signal.empty() || userName.empty() ||
+        (signal == userRenamedSignal && newUserName.empty()))
+    {
+        log<level::ERR>("Invalid inputs received");
+        return;
+    }
+
+    boost::interprocess::scoped_lock<boost::interprocess::named_recursive_mutex>
+        userLock{*(usrAccess.userMutex)};
+    usrAccess.checkAndReloadUserData();
+
+    if (signal == propertiesChangedSignal)
+    {
+        std::string intfName;
+        DbusUserObjProperties chProperties;
+        msg.read(intfName, chProperties); // skip reading 3rd argument.
+        for (const auto& prop : chProperties)
+        {
+            userEvent = UserUpdateEvent::reservedEvent;
+            std::string member = prop.first;
+            if (member == userPrivProperty)
+            {
+                priv = prop.second.get<std::string>();
+                userEvent = UserUpdateEvent::userPrivUpdated;
+            }
+            else if (member == userGrpProperty)
+            {
+                groups = prop.second.get<std::vector<std::string>>();
+                userEvent = UserUpdateEvent::userGrpUpdated;
+            }
+            else if (member == userEnabledProperty)
+            {
+                enabled = prop.second.get<bool>();
+                userEvent = UserUpdateEvent::userStateUpdated;
+            }
+            // Process based on event type.
+            if (userEvent == UserUpdateEvent::userGrpUpdated)
+            {
+                if (std::find(groups.begin(), groups.end(), ipmiGrpName) ==
+                    groups.end())
+                {
+                    // remove user from ipmi user list.
+                    userUpdateHelper(usrAccess, UserUpdateEvent::userDeleted,
+                                     userName, priv, enabled, newUserName);
+                }
+                else
+                {
+                    DbusUserObjProperties properties;
+                    try
+                    {
+                        auto method = bus.new_method_call(
+                            getUserServiceName().c_str(), msg.get_path(),
+                            dBusPropertiesInterface, getAllPropertiesMethod);
+                        method.append(usersInterface);
+                        auto reply = bus.call(method);
+                        reply.read(properties);
+                    }
+                    catch (const sdbusplus::exception::SdBusError& e)
+                    {
+                        log<level::DEBUG>(
+                            "Failed to excute method",
+                            entry("METHOD=%s", getAllPropertiesMethod),
+                            entry("PATH=%s", msg.get_path()));
+                        return;
+                    }
+                    usrAccess.getUserProperties(properties, groups, priv,
+                                                enabled);
+                    // add user to ipmi user list.
+                    userUpdateHelper(usrAccess, UserUpdateEvent::userCreated,
+                                     userName, priv, enabled, newUserName);
+                }
+            }
+            else if (userEvent != UserUpdateEvent::reservedEvent)
+            {
+                userUpdateHelper(usrAccess, userEvent, userName, priv, enabled,
+                                 newUserName);
+            }
+        }
+    }
+    else if (userEvent != UserUpdateEvent::reservedEvent)
+    {
+        userUpdateHelper(usrAccess, userEvent, userName, priv, enabled,
+                         newUserName);
+    }
+    return;
+}
+
+UserAccess::~UserAccess()
+{
+    if (signalHndlrObject)
+    {
+        userUpdatedSignal.reset();
+        userMgrRenamedSignal.reset();
+        userPropertiesSignal.reset();
+        sigHndlrLock.unlock();
+    }
+}
+
+UserAccess::UserAccess() : bus(ipmid_get_sd_bus_connection())
+{
+    std::ofstream mutexCleanUpFile;
+    mutexCleanUpFile.open(ipmiMutexCleanupLockFile,
+                          std::ofstream::out | std::ofstream::app);
+    if (!mutexCleanUpFile.good())
+    {
+        log<level::DEBUG>("Unable to open mutex cleanup file");
+        return;
+    }
+    mutexCleanUpFile.close();
+    mutexCleanupLock = boost::interprocess::file_lock(ipmiMutexCleanupLockFile);
+    if (mutexCleanupLock.try_lock())
+    {
+        boost::interprocess::named_recursive_mutex::remove(ipmiUserMutex);
+    }
+    mutexCleanupLock.lock_sharable();
+    userMutex = std::make_unique<boost::interprocess::named_recursive_mutex>(
+        boost::interprocess::open_or_create, ipmiUserMutex);
+
+    initUserDataFile();
+    getSystemPrivAndGroups();
+    sigHndlrLock = boost::interprocess::file_lock(ipmiUserDataFile);
+    // Register it for single object and single process either netipimd /
+    // host-ipmid
+    if (userUpdatedSignal == nullptr && sigHndlrLock.try_lock())
+    {
+        log<level::DEBUG>("Registering signal handler");
+        userUpdatedSignal = std::make_unique<sdbusplus::bus::match_t>(
+            bus,
+            sdbusplus::bus::match::rules::type::signal() +
+                sdbusplus::bus::match::rules::interface(dBusObjManager) +
+                sdbusplus::bus::match::rules::path(userMgrObjBasePath),
+            [&](sdbusplus::message::message& msg) {
+                userUpdatedSignalHandler(*this, msg);
+            });
+        userMgrRenamedSignal = std::make_unique<sdbusplus::bus::match_t>(
+            bus,
+            sdbusplus::bus::match::rules::type::signal() +
+                sdbusplus::bus::match::rules::interface(userMgrInterface) +
+                sdbusplus::bus::match::rules::path(userMgrObjBasePath),
+            [&](sdbusplus::message::message& msg) {
+                userUpdatedSignalHandler(*this, msg);
+            });
+        userPropertiesSignal = std::make_unique<sdbusplus::bus::match_t>(
+            bus,
+            sdbusplus::bus::match::rules::type::signal() +
+                sdbusplus::bus::match::rules::path_namespace(userObjBasePath) +
+                sdbusplus::bus::match::rules::interface(
+                    dBusPropertiesInterface) +
+                sdbusplus::bus::match::rules::member(propertiesChangedSignal) +
+                sdbusplus::bus::match::rules::argN(0, usersInterface),
+            [&](sdbusplus::message::message& msg) {
+                userUpdatedSignalHandler(*this, msg);
+            });
+        signalHndlrObject = true;
+    }
+}
+
+UserInfo* UserAccess::getUserInfo(const uint8_t& userId)
+{
+    checkAndReloadUserData();
+    return &usersTbl.user[userId];
+}
+
+void UserAccess::setUserInfo(const uint8_t& userId, UserInfo* userInfo)
+{
+    checkAndReloadUserData();
+    std::copy(reinterpret_cast<uint8_t*>(userInfo),
+              reinterpret_cast<uint8_t*>(userInfo) + sizeof(*userInfo),
+              reinterpret_cast<uint8_t*>(&usersTbl.user[userId]));
+    writeUserData();
+}
+
+bool UserAccess::isValidChannel(const uint8_t& chNum)
+{
+    return (chNum < ipmiMaxChannels);
+}
+
+bool UserAccess::isValidUserId(const uint8_t& userId)
+{
+    return ((userId <= ipmiMaxUsers) && (userId != reservedUserId));
+}
+
+bool UserAccess::isValidPrivilege(const uint8_t& priv)
+{
+    return ((priv >= PRIVILEGE_CALLBACK && priv <= PRIVILEGE_OEM) ||
+            priv == privNoAccess);
+}
+
+uint8_t UserAccess::getUsrMgmtSyncIndex()
+{
+    // TODO: Need to get LAN1 channel number dynamically,
+    // which has to be in sync with system user privilege
+    // level(Phosphor-user-manager). Note: For time being chanLan1 is marked as
+    // sync index to the user-manager privilege..
+    return static_cast<uint8_t>(EChannelID::chanLan1);
+}
+
+CommandPrivilege UserAccess::convertToIPMIPrivilege(const std::string& value)
+{
+    auto iter = std::find(ipmiPrivIndex.begin(), ipmiPrivIndex.end(), value);
+    if (iter == ipmiPrivIndex.end())
+    {
+        if (value == "")
+        {
+            return static_cast<CommandPrivilege>(privNoAccess);
+        }
+        log<level::ERR>("Error in converting to IPMI privilege",
+                        entry("PRIV=%s", value.c_str()));
+        throw std::out_of_range("Out of range - convertToIPMIPrivilege");
+    }
+    else
+    {
+        return static_cast<CommandPrivilege>(
+            std::distance(ipmiPrivIndex.begin(), iter));
+    }
+}
+
+std::string UserAccess::convertToSystemPrivilege(const CommandPrivilege& value)
+{
+    if (value == static_cast<CommandPrivilege>(privNoAccess))
+    {
+        return "";
+    }
+    try
+    {
+        return ipmiPrivIndex.at(value);
+    }
+    catch (const std::out_of_range& e)
+    {
+        log<level::ERR>("Error in converting to system privilege",
+                        entry("PRIV=%d", static_cast<uint8_t>(value)));
+        throw std::out_of_range("Out of range - convertToSystemPrivilege");
+    }
+}
+
+bool UserAccess::isValidUserName(const char* userNameInChar)
+{
+    if (!userNameInChar)
+    {
+        log<level::ERR>("null ptr");
+        return false;
+    }
+    std::string userName(userNameInChar, 0, ipmiMaxUserName);
+    if (!std::regex_match(userName.c_str(),
+                          std::regex("[a-zA-z_][a-zA-Z_0-9]*")))
+    {
+        log<level::ERR>("Unsupported characters in user name");
+        return false;
+    }
+    if (userName == "root")
+    {
+        log<level::ERR>("Invalid user name - root");
+        return false;
+    }
+    std::map<DbusUserObjPath, DbusUserObjValue> properties;
+    try
+    {
+        auto method = bus.new_method_call(getUserServiceName().c_str(),
+                                          userMgrObjBasePath, dBusObjManager,
+                                          getManagedObjectsMethod);
+        auto reply = bus.call(method);
+        reply.read(properties);
+    }
+    catch (const sdbusplus::exception::SdBusError& e)
+    {
+        log<level::ERR>("Failed to excute method",
+                        entry("METHOD=%s", getSubTreeMethod),
+                        entry("PATH=%s", userMgrObjBasePath));
+        return false;
+    }
+
+    std::string usersPath = std::string(userObjBasePath) + "/" + userName;
+    if (properties.find(usersPath) != properties.end())
+    {
+        log<level::DEBUG>("User name already exists",
+                          entry("USER_NAME=%s", userName.c_str()));
+        return false;
+    }
+
+    return true;
+}
+
+ipmi_ret_t UserAccess::setUserPrivilegeAccess(const uint8_t& userId,
+                                              const uint8_t& chNum,
+                                              const UserPrivAccess& privAccess,
+                                              const bool& otherPrivUpdates)
+{
+    if (!isValidChannel(chNum))
+    {
+        return IPMI_CC_INVALID_FIELD_REQUEST;
+    }
+    if (!isValidUserId(userId))
+    {
+        return IPMI_CC_PARM_OUT_OF_RANGE;
+    }
+    boost::interprocess::scoped_lock<boost::interprocess::named_recursive_mutex>
+        userLock{*userMutex};
+    UserInfo* userInfo = getUserInfo(userId);
+    std::string userName;
+    userName.assign(reinterpret_cast<char*>(userInfo->userName), 0,
+                    ipmiMaxUserName);
+    if (userName.empty())
+    {
+        log<level::DEBUG>("User name not set / invalid");
+        return IPMI_CC_UNSPECIFIED_ERROR;
+    }
+    std::string priv = convertToSystemPrivilege(
+        static_cast<CommandPrivilege>(privAccess.privilege));
+    if (priv.empty())
+    {
+        return IPMI_CC_PARM_OUT_OF_RANGE;
+    }
+    uint8_t syncIndex = getUsrMgmtSyncIndex();
+    if (chNum == syncIndex &&
+        privAccess.privilege != userInfo->userPrivAccess[syncIndex].privilege)
+    {
+        std::string userPath = std::string(userObjBasePath) + "/" + userName;
+        setDbusProperty(bus, getUserServiceName().c_str(), userPath.c_str(),
+                        usersInterface, userPrivProperty, priv);
+    }
+    userInfo->userPrivAccess[chNum].privilege = privAccess.privilege;
+
+    if (otherPrivUpdates)
+    {
+        userInfo->userPrivAccess[chNum].ipmiEnabled = privAccess.ipmiEnabled;
+        userInfo->userPrivAccess[chNum].linkAuthEnabled =
+            privAccess.linkAuthEnabled;
+        userInfo->userPrivAccess[chNum].accessCallback =
+            privAccess.accessCallback;
+    }
+    try
+    {
+        writeUserData();
+    }
+    catch (const std::exception& e)
+    {
+        log<level::DEBUG>("Write user data failed");
+        return IPMI_CC_UNSPECIFIED_ERROR;
+    }
+    return IPMI_CC_OK;
+}
+
+uint8_t UserAccess::getUserId(const std::string& userName)
+{
+    boost::interprocess::scoped_lock<boost::interprocess::named_recursive_mutex>
+        userLock{*userMutex};
+    checkAndReloadUserData();
+    // user index 0 is reserved, starts with 1
+    size_t usrIndex = 1;
+    for (; usrIndex <= ipmiMaxUsers; ++usrIndex)
+    {
+        std::string curName(
+            reinterpret_cast<char*>(usersTbl.user[usrIndex].userName), 0,
+            ipmiMaxUserName);
+        if (userName == curName)
+        {
+            break; // found the entry
+        }
+    }
+    if (usrIndex > ipmiMaxUsers)
+    {
+        log<level::DEBUG>("User not found",
+                          entry("USER_NAME=%s", userName.c_str()));
+        return invalidUserId;
+    }
+
+    return usrIndex;
+}
+
+ipmi_ret_t UserAccess::getUserName(const uint8_t& userId, std::string& userName)
+{
+    if (!isValidUserId(userId))
+    {
+        return IPMI_CC_PARM_OUT_OF_RANGE;
+    }
+    UserInfo* userInfo = getUserInfo(userId);
+    userName.assign(reinterpret_cast<char*>(userInfo->userName), 0,
+                    ipmiMaxUserName);
+    return IPMI_CC_OK;
+}
+
+ipmi_ret_t UserAccess::setUserName(const uint8_t& userId,
+                                   const char* userNameInChar)
+{
+    if (!isValidUserId(userId))
+    {
+        return IPMI_CC_PARM_OUT_OF_RANGE;
+    }
+
+    boost::interprocess::scoped_lock<boost::interprocess::named_recursive_mutex>
+        userLock{*userMutex};
+    bool validUser = isValidUserName(userNameInChar);
+    std::string oldUser;
+    getUserName(userId, oldUser);
+    UserInfo* userInfo = getUserInfo(userId);
+
+    std::string newUser(userNameInChar, 0, ipmiMaxUserName);
+    if (newUser.empty() && !oldUser.empty())
+    {
+        // Delete existing user
+        std::string userPath = std::string(userObjBasePath) + "/" + oldUser;
+        try
+        {
+            auto method = bus.new_method_call(
+                getUserServiceName().c_str(), userPath.c_str(),
+                deleteUserInterface, deleteUserMethod);
+            auto reply = bus.call(method);
+        }
+        catch (const sdbusplus::exception::SdBusError& e)
+        {
+            log<level::DEBUG>("Failed to excute method",
+                              entry("METHOD=%s", deleteUserMethod),
+                              entry("PATH=%s", userPath.c_str()));
+            return IPMI_CC_UNSPECIFIED_ERROR;
+        }
+        std::fill(userInfo->userName,
+                  userInfo->userName + sizeof(userInfo->userName), 0);
+        ipmiClearUserEntryPassword(oldUser);
+        userInfo->userInSystem = false;
+    }
+    else if (oldUser.empty() && !newUser.empty() && validUser)
+    {
+        try
+        {
+            // Create new user
+            auto method = bus.new_method_call(
+                getUserServiceName().c_str(), userMgrObjBasePath,
+                userMgrInterface, createUserMethod);
+            // TODO: Fetch proper privilege & enable state once set User access
+            // is implemented if LAN Channel specified, then create user for all
+            // groups follow channel privilege for user creation.
+            method.append(newUser.c_str(), availableGroups, "priv-admin", true);
+            auto reply = bus.call(method);
+        }
+        catch (const sdbusplus::exception::SdBusError& e)
+        {
+            log<level::DEBUG>("Failed to excute method",
+                              entry("METHOD=%s", createUserMethod),
+                              entry("PATH=%s", userMgrObjBasePath));
+            return IPMI_CC_UNSPECIFIED_ERROR;
+        }
+        std::strncpy(reinterpret_cast<char*>(userInfo->userName),
+                     userNameInChar, ipmiMaxUserName);
+        userInfo->userInSystem = true;
+    }
+    else if (oldUser != newUser && validUser)
+    {
+        try
+        {
+            // User rename
+            auto method = bus.new_method_call(
+                getUserServiceName().c_str(), userMgrObjBasePath,
+                userMgrInterface, renameUserMethod);
+            method.append(oldUser.c_str(), newUser.c_str());
+            auto reply = bus.call(method);
+        }
+        catch (const sdbusplus::exception::SdBusError& e)
+        {
+            log<level::DEBUG>("Failed to excute method",
+                              entry("METHOD=%s", renameUserMethod),
+                              entry("PATH=%s", userMgrObjBasePath));
+            return IPMI_CC_UNSPECIFIED_ERROR;
+        }
+        std::fill(static_cast<uint8_t*>(userInfo->userName),
+                  static_cast<uint8_t*>(userInfo->userName) +
+                      sizeof(userInfo->userName),
+                  0);
+        std::strncpy(reinterpret_cast<char*>(userInfo->userName),
+                     userNameInChar, ipmiMaxUserName);
+        ipmiRenameUserEntryPassword(oldUser, newUser);
+        userInfo->userInSystem = true;
+    }
+    else if (!validUser)
+    {
+        return IPMI_CC_INVALID_FIELD_REQUEST;
+    }
+    try
+    {
+        writeUserData();
+    }
+    catch (const std::exception& e)
+    {
+        log<level::DEBUG>("Write user data failed");
+        return IPMI_CC_UNSPECIFIED_ERROR;
+    }
+    return IPMI_CC_OK;
+}
+
+static constexpr const char* jsonUserName = "user_name";
+static constexpr const char* jsonPriv = "privilege";
+static constexpr const char* jsonIpmiEnabled = "ipmi_enabled";
+static constexpr const char* jsonLinkAuthEnabled = "link_auth_enabled";
+static constexpr const char* jsonAccCallbk = "access_callback";
+static constexpr const char* jsonUserEnabled = "user_enabled";
+static constexpr const char* jsonUserInSys = "user_in_system";
+static constexpr const char* jsonFixedUser = "fixed_user_name";
+
+void UserAccess::readUserData()
+{
+    boost::interprocess::scoped_lock<boost::interprocess::named_recursive_mutex>
+        userLock{*userMutex};
+
+    std::ifstream iUsrData(ipmiUserDataFile, std::ios::in | std::ios::binary);
+    if (!iUsrData.good())
+    {
+        log<level::ERR>("Error in reading IPMI user data file");
+        throw std::ios_base::failure("Error opening IPMI user data file");
+    }
+
+    Json jsonUsersTbl = Json::array();
+    jsonUsersTbl = Json::parse(iUsrData, nullptr, false);
+
+    if (jsonUsersTbl.size() != ipmiMaxUsers)
+    {
+        log<level::ERR>(
+            "Error in reading IPMI user data file - User count issues");
+        throw std::runtime_error(
+            "Corrupted IPMI user data file - invalid user count");
+    }
+    // user index 0 is reserved, starts with 1
+    for (size_t usrIndex = 1; usrIndex <= ipmiMaxUsers; ++usrIndex)
+    {
+        Json userInfo = jsonUsersTbl[usrIndex - 1]; // json array starts with 0.
+        if (userInfo.is_null())
+        {
+            log<level::ERR>("Error in reading IPMI user data file - "
+                            "user info corrupted");
+            throw std::runtime_error(
+                "Corrupted IPMI user data file - invalid user info");
+        }
+        std::string userName = userInfo[jsonUserName].get<std::string>();
+        std::strncpy(reinterpret_cast<char*>(usersTbl.user[usrIndex].userName),
+                     userName.c_str(), ipmiMaxUserName);
+
+        std::vector<std::string> privilege =
+            userInfo[jsonPriv].get<std::vector<std::string>>();
+        std::vector<bool> ipmiEnabled =
+            userInfo[jsonIpmiEnabled].get<std::vector<bool>>();
+        std::vector<bool> linkAuthEnabled =
+            userInfo[jsonLinkAuthEnabled].get<std::vector<bool>>();
+        std::vector<bool> accessCallback =
+            userInfo[jsonAccCallbk].get<std::vector<bool>>();
+        if (privilege.size() != ipmiMaxChannels ||
+            ipmiEnabled.size() != ipmiMaxChannels ||
+            linkAuthEnabled.size() != ipmiMaxChannels ||
+            accessCallback.size() != ipmiMaxChannels)
+        {
+            log<level::ERR>("Error in reading IPMI user data file - "
+                            "properties corrupted");
+            throw std::runtime_error(
+                "Corrupted IPMI user data file - properties");
+        }
+        for (size_t chIndex = 0; chIndex < ipmiMaxChannels; ++chIndex)
+        {
+            usersTbl.user[usrIndex].userPrivAccess[chIndex].privilege =
+                static_cast<uint8_t>(
+                    convertToIPMIPrivilege(privilege[chIndex]));
+            usersTbl.user[usrIndex].userPrivAccess[chIndex].ipmiEnabled =
+                ipmiEnabled[chIndex];
+            usersTbl.user[usrIndex].userPrivAccess[chIndex].linkAuthEnabled =
+                linkAuthEnabled[chIndex];
+            usersTbl.user[usrIndex].userPrivAccess[chIndex].accessCallback =
+                accessCallback[chIndex];
+        }
+        usersTbl.user[usrIndex].userEnabled =
+            userInfo[jsonUserEnabled].get<bool>();
+        usersTbl.user[usrIndex].userInSystem =
+            userInfo[jsonUserInSys].get<bool>();
+        usersTbl.user[usrIndex].fixedUserName =
+            userInfo[jsonFixedUser].get<bool>();
+    }
+
+    log<level::DEBUG>("User data read from IPMI data file");
+    iUsrData.close();
+    // Update the timestamp
+    fileLastUpdatedTime = getUpdatedFileTime();
+    return;
+}
+
+void UserAccess::writeUserData()
+{
+    boost::interprocess::scoped_lock<boost::interprocess::named_recursive_mutex>
+        userLock{*userMutex};
+
+    static std::string tmpFile{std::string(ipmiUserDataFile) + "_tmp"};
+    std::ofstream oUsrData(tmpFile, std::ios::out | std::ios::binary);
+    if (!oUsrData.good())
+    {
+        log<level::ERR>("Error in creating temporary IPMI user data file");
+        throw std::ios_base::failure(
+            "Error in creating temporary IPMI user data file");
+    }
+
+    Json jsonUsersTbl = Json::array();
+    // user index 0 is reserved, starts with 1
+    for (size_t usrIndex = 1; usrIndex <= ipmiMaxUsers; ++usrIndex)
+    {
+        Json jsonUserInfo;
+        jsonUserInfo[jsonUserName] = std::string(
+            reinterpret_cast<char*>(usersTbl.user[usrIndex].userName), 0,
+            ipmiMaxUserName);
+        std::vector<std::string> privilege(ipmiMaxChannels);
+        std::vector<bool> ipmiEnabled(ipmiMaxChannels);
+        std::vector<bool> linkAuthEnabled(ipmiMaxChannels);
+        std::vector<bool> accessCallback(ipmiMaxChannels);
+        for (size_t chIndex = 0; chIndex < ipmiMaxChannels; chIndex++)
+        {
+            privilege[chIndex] =
+                convertToSystemPrivilege(static_cast<CommandPrivilege>(
+                    usersTbl.user[usrIndex].userPrivAccess[chIndex].privilege));
+            ipmiEnabled[chIndex] =
+                usersTbl.user[usrIndex].userPrivAccess[chIndex].ipmiEnabled;
+            linkAuthEnabled[chIndex] =
+                usersTbl.user[usrIndex].userPrivAccess[chIndex].linkAuthEnabled;
+            accessCallback[chIndex] =
+                usersTbl.user[usrIndex].userPrivAccess[chIndex].accessCallback;
+        }
+        jsonUserInfo[jsonPriv] = privilege;
+        jsonUserInfo[jsonIpmiEnabled] = ipmiEnabled;
+        jsonUserInfo[jsonLinkAuthEnabled] = linkAuthEnabled;
+        jsonUserInfo[jsonAccCallbk] = accessCallback;
+        jsonUserInfo[jsonUserEnabled] = usersTbl.user[usrIndex].userEnabled;
+        jsonUserInfo[jsonUserInSys] = usersTbl.user[usrIndex].userInSystem;
+        jsonUserInfo[jsonFixedUser] = usersTbl.user[usrIndex].fixedUserName;
+        jsonUsersTbl.push_back(jsonUserInfo);
+    }
+
+    oUsrData << jsonUsersTbl;
+    oUsrData.flush();
+    oUsrData.close();
+
+    if (std::rename(tmpFile.c_str(), ipmiUserDataFile) != 0)
+    {
+        log<level::ERR>("Error in renaming temporary IPMI user data file");
+        throw std::runtime_error("Error in renaming IPMI user data file");
+    }
+    // Update the timestamp
+    fileLastUpdatedTime = getUpdatedFileTime();
+    return;
+}
+
+bool UserAccess::addUserEntry(const std::string& userName,
+                              const std::string& sysPriv, const bool& enabled)
+{
+    UsersTbl* userData = getUsersTblPtr();
+    size_t freeIndex = 0xFF;
+    // user index 0 is reserved, starts with 1
+    for (size_t usrIndex = 1; usrIndex <= ipmiMaxUsers; ++usrIndex)
+    {
+        std::string curName(
+            reinterpret_cast<char*>(userData->user[usrIndex].userName), 0,
+            ipmiMaxUserName);
+        if (userName == curName)
+        {
+            log<level::DEBUG>("User name exists",
+                              entry("USER_NAME=%s", userName.c_str()));
+            return false; // user name exists.
+        }
+
+        if ((!userData->user[usrIndex].userInSystem) &&
+            (userData->user[usrIndex].userName[0] == '\0') &&
+            (freeIndex == 0xFF))
+        {
+            freeIndex = usrIndex;
+        }
+    }
+    if (freeIndex == 0xFF)
+    {
+        log<level::ERR>("No empty slots found");
+        return false;
+    }
+    std::strncpy(reinterpret_cast<char*>(userData->user[freeIndex].userName),
+                 userName.c_str(), ipmiMaxUserName);
+    uint8_t priv =
+        static_cast<uint8_t>(UserAccess::convertToIPMIPrivilege(sysPriv)) &
+        privMask;
+    for (size_t chIndex = 0; chIndex < ipmiMaxChannels; ++chIndex)
+    {
+        userData->user[freeIndex].userPrivAccess[chIndex].privilege = priv;
+        userData->user[freeIndex].userPrivAccess[chIndex].ipmiEnabled = true;
+        userData->user[freeIndex].userPrivAccess[chIndex].linkAuthEnabled =
+            true;
+        userData->user[freeIndex].userPrivAccess[chIndex].accessCallback = true;
+    }
+    userData->user[freeIndex].userInSystem = true;
+    userData->user[freeIndex].userEnabled = enabled;
+
+    return true;
+}
+
+void UserAccess::deleteUserIndex(const size_t& usrIdx)
+{
+    UsersTbl* userData = getUsersTblPtr();
+
+    std::string userName(
+        reinterpret_cast<char*>(userData->user[usrIdx].userName), 0,
+        ipmiMaxUserName);
+    ipmiClearUserEntryPassword(userName);
+    std::fill(static_cast<uint8_t*>(userData->user[usrIdx].userName),
+              static_cast<uint8_t*>(userData->user[usrIdx].userName) +
+                  sizeof(userData->user[usrIdx].userName),
+              0);
+    for (size_t chIndex = 0; chIndex < ipmiMaxChannels; ++chIndex)
+    {
+        userData->user[usrIdx].userPrivAccess[chIndex].privilege = privNoAccess;
+        userData->user[usrIdx].userPrivAccess[chIndex].ipmiEnabled = false;
+        userData->user[usrIdx].userPrivAccess[chIndex].linkAuthEnabled = false;
+        userData->user[usrIdx].userPrivAccess[chIndex].accessCallback = false;
+    }
+    userData->user[usrIdx].userInSystem = false;
+    userData->user[usrIdx].userEnabled = false;
+    return;
+}
+
+void UserAccess::checkAndReloadUserData()
+{
+    std::time_t updateTime = getUpdatedFileTime();
+    if (updateTime != fileLastUpdatedTime || updateTime == -EIO)
+    {
+        std::fill(reinterpret_cast<uint8_t*>(&usersTbl),
+                  reinterpret_cast<uint8_t*>(&usersTbl) + sizeof(usersTbl), 0);
+        readUserData();
+    }
+    return;
+}
+
+UsersTbl* UserAccess::getUsersTblPtr()
+{
+    // reload data before using it.
+    checkAndReloadUserData();
+    return &usersTbl;
+}
+
+void UserAccess::getSystemPrivAndGroups()
+{
+    std::map<std::string, PrivAndGroupType> properties;
+    try
+    {
+        auto method = bus.new_method_call(
+            getUserServiceName().c_str(), userMgrObjBasePath,
+            dBusPropertiesInterface, getAllPropertiesMethod);
+        method.append(userMgrInterface);
+
+        auto reply = bus.call(method);
+        reply.read(properties);
+    }
+    catch (const sdbusplus::exception::SdBusError& e)
+    {
+        log<level::DEBUG>("Failed to excute method",
+                          entry("METHOD=%s", getAllPropertiesMethod),
+                          entry("PATH=%s", userMgrObjBasePath));
+        return;
+    }
+    for (const auto& t : properties)
+    {
+        auto key = t.first;
+        if (key == allPrivProperty)
+        {
+            availablePrivileges = t.second.get<std::vector<std::string>>();
+        }
+        else if (key == allGrpProperty)
+        {
+            availableGroups = t.second.get<std::vector<std::string>>();
+        }
+    }
+    // TODO: Implement Supported Privilege & Groups verification logic
+    return;
+}
+
+std::time_t UserAccess::getUpdatedFileTime()
+{
+    struct stat fileStat;
+    if (stat(ipmiUserDataFile, &fileStat) != 0)
+    {
+        log<level::DEBUG>("Error in getting last updated time stamp");
+        return -EIO;
+    }
+    return fileStat.st_mtime;
+}
+
+void UserAccess::getUserProperties(const DbusUserObjProperties& properties,
+                                   std::vector<std::string>& usrGrps,
+                                   std::string& usrPriv, bool& usrEnabled)
+{
+    for (const auto& t : properties)
+    {
+        std::string key = t.first;
+        if (key == userPrivProperty)
+        {
+            usrPriv = t.second.get<std::string>();
+        }
+        else if (key == userGrpProperty)
+        {
+            usrGrps = t.second.get<std::vector<std::string>>();
+        }
+        else if (key == userEnabledProperty)
+        {
+            usrEnabled = t.second.get<bool>();
+        }
+    }
+    return;
+}
+
+int UserAccess::getUserObjProperties(const DbusUserObjValue& userObjs,
+                                     std::vector<std::string>& usrGrps,
+                                     std::string& usrPriv, bool& usrEnabled)
+{
+    auto usrObj = userObjs.find(usersInterface);
+    if (usrObj != userObjs.end())
+    {
+        getUserProperties(usrObj->second, usrGrps, usrPriv, usrEnabled);
+        return 0;
+    }
+    return -EIO;
+}
+
+void UserAccess::initUserDataFile()
+{
+    boost::interprocess::scoped_lock<boost::interprocess::named_recursive_mutex>
+        userLock{*userMutex};
+    try
+    {
+        readUserData();
+    }
+    catch (const std::ios_base::failure& e)
+    { // File is empty, create it for the first time
+        std::fill(reinterpret_cast<uint8_t*>(&usersTbl),
+                  reinterpret_cast<uint8_t*>(&usersTbl) + sizeof(usersTbl), 0);
+        // user index 0 is reserved, starts with 1
+        for (size_t userIndex = 1; userIndex <= ipmiMaxUsers; ++userIndex)
+        {
+            for (size_t chIndex = 0; chIndex < ipmiMaxChannels; ++chIndex)
+            {
+                usersTbl.user[userIndex].userPrivAccess[chIndex].privilege =
+                    privNoAccess;
+            }
+        }
+        writeUserData();
+    }
+    std::map<DbusUserObjPath, DbusUserObjValue> managedObjs;
+    try
+    {
+        auto method = bus.new_method_call(getUserServiceName().c_str(),
+                                          userMgrObjBasePath, dBusObjManager,
+                                          getManagedObjectsMethod);
+        auto reply = bus.call(method);
+        reply.read(managedObjs);
+    }
+    catch (const sdbusplus::exception::SdBusError& e)
+    {
+        log<level::DEBUG>("Failed to excute method",
+                          entry("METHOD=%s", getSubTreeMethod),
+                          entry("PATH=%s", userMgrObjBasePath));
+        return;
+    }
+
+    UsersTbl* userData = &usersTbl;
+    // user index 0 is reserved, starts with 1
+    for (size_t usrIdx = 1; usrIdx <= ipmiMaxUsers; ++usrIdx)
+    {
+        if ((userData->user[usrIdx].userInSystem) &&
+            (userData->user[usrIdx].userName[0] != '\0'))
+        {
+            std::vector<std::string> usrGrps;
+            std::string usrPriv;
+            bool usrEnabled;
+
+            std::string userName(
+                reinterpret_cast<char*>(userData->user[usrIdx].userName), 0,
+                ipmiMaxUserName);
+            std::string usersPath =
+                std::string(userObjBasePath) + "/" + userName;
+
+            auto usrObj = managedObjs.find(usersPath);
+            if (usrObj != managedObjs.end())
+            {
+                // User exist. Lets check and update other fileds
+                getUserObjProperties(usrObj->second, usrGrps, usrPriv,
+                                     usrEnabled);
+                if (std::find(usrGrps.begin(), usrGrps.end(), ipmiGrpName) ==
+                    usrGrps.end())
+                {
+                    // Group "ipmi" is removed so lets remove user in IPMI
+                    deleteUserIndex(usrIdx);
+                }
+                else
+                {
+                    // Group "ipmi" is present so lets update other properties
+                    // in IPMI
+                    uint8_t priv =
+                        UserAccess::convertToIPMIPrivilege(usrPriv) & privMask;
+                    // Update all channels priv, only if it is not equivalent to
+                    // getUsrMgmtSyncIndex()
+                    if (userData->user[usrIdx]
+                            .userPrivAccess[getUsrMgmtSyncIndex()]
+                            .privilege != priv)
+                    {
+                        for (size_t chIndex = 0; chIndex < ipmiMaxChannels;
+                             ++chIndex)
+                        {
+                            userData->user[usrIdx]
+                                .userPrivAccess[chIndex]
+                                .privilege = priv;
+                        }
+                    }
+                    if (userData->user[usrIdx].userEnabled != usrEnabled)
+                    {
+                        userData->user[usrIdx].userEnabled = usrEnabled;
+                    }
+                }
+
+                // We are done with this obj. lets delete from MAP
+                managedObjs.erase(usrObj);
+            }
+            else
+            {
+                deleteUserIndex(usrIdx);
+            }
+        }
+    }
+
+    // Walk through remnaining managedObj users list
+    // Add them to ipmi data base
+    for (const auto& usrObj : managedObjs)
+    {
+        std::vector<std::string> usrGrps;
+        std::string usrPriv, userName;
+        bool usrEnabled;
+        std::string usrObjPath = std::string(usrObj.first);
+        if (getUserNameFromPath(usrObj.first.str, userName) != 0)
+        {
+            log<level::ERR>("Error in user object path");
+            continue;
+        }
+        getUserObjProperties(usrObj.second, usrGrps, usrPriv, usrEnabled);
+        // Add 'ipmi' group users
+        if (std::find(usrGrps.begin(), usrGrps.end(), ipmiGrpName) !=
+            usrGrps.end())
+        {
+            // CREATE NEW USER
+            if (true != addUserEntry(userName, usrPriv, usrEnabled))
+            {
+                break;
+            }
+        }
+    }
+
+    // All userData slots update done. Lets write the data
+    writeUserData();
+
+    return;
+}
+} // namespace ipmi