sdbusplus.hpp

#pragma once

#include <sdbusplus/bus.hpp>
#include <sdbusplus/message.hpp>
#include <sdbusplus/bus/match.hpp>
#include <phosphor-logging/log.hpp>
#include <phosphor-logging/elog.hpp>
#include <phosphor-logging/elog-errors.hpp>
#include <xyz/openbmc_project/Common/error.hpp>

namespace phosphor
{
namespace fan
{
namespace util
{
namespace detail
{
namespace errors = sdbusplus::xyz::openbmc_project::Common::Error;
} // namespace detail

/**
 * @class DBusError
 *
 * The base class for the exceptions thrown on fails in the various
 * SDBusPlus calls.  Used so that a single catch statement can catch
 * any type of these exceptions.
 *
 * None of these exceptions will log anything when they are created,
 * it is up to the handler to do that if desired.
 */
class DBusError : public std::runtime_error
{
    public:
        DBusError(const char* msg) :
            std::runtime_error(msg)
        {
        }
};

/**
 * @class DBusMethodError
 *
 * Thrown on a DBus Method call failure
 */
class DBusMethodError : public DBusError
{
    public:
        DBusMethodError(
                const std::string& busName,
                const std::string& path,
                const std::string& interface,
                const std::string& method) :
            DBusError("DBus method call failed"),
            busName(busName),
            path(path),
            interface(interface),
            method(method)
            {
            }

        const std::string busName;
        const std::string path;
        const std::string interface;
        const std::string method;
};

/**
 * @class DBusServiceError
 *
 * Thrown when a service lookup fails.  Usually this points to
 * the object path not being present in D-Bus.
 */
class DBusServiceError : public DBusError
{
    public:
        DBusServiceError(
                const std::string& path,
                const std::string& interface) :
            DBusError("DBus service lookup failed"),
            path(path),
            interface(interface)
            {
            }

        const std::string path;
        const std::string interface;
};

/** @brief Alias for PropertiesChanged signal callbacks. */
template <typename ...T>
using Properties = std::map<std::string, sdbusplus::message::variant<T...>>;

/** @class SDBusPlus
 *  @brief DBus access delegate implementation for sdbusplus.
 */
class SDBusPlus
{

    public:
        /** @brief Get the bus connection. */
        static auto& getBus() __attribute__((pure))
        {
            static auto bus = sdbusplus::bus::new_default();
            return bus;
        }

        /** @brief Invoke a method. */
        template <typename ...Args>
        static auto callMethod(
            sdbusplus::bus::bus& bus,
            const std::string& busName,
            const std::string& path,
            const std::string& interface,
            const std::string& method,
            Args&& ... args)
        {
            auto reqMsg = bus.new_method_call(
                    busName.c_str(),
                    path.c_str(),
                    interface.c_str(),
                    method.c_str());
            reqMsg.append(std::forward<Args>(args)...);
            auto respMsg = bus.call(reqMsg);

            if (respMsg.is_method_error())
            {
                throw DBusMethodError{busName, path, interface, method};
            }

            return respMsg;
        }

        /** @brief Invoke a method. */
        template <typename ...Args>
        static auto callMethod(
            const std::string& busName,
            const std::string& path,
            const std::string& interface,
            const std::string& method,
            Args&& ... args)
        {
            return callMethod(
                    getBus(),
                    busName,
                    path,
                    interface,
                    method,
                    std::forward<Args>(args)...);
        }

        /** @brief Invoke a method and read the response. */
        template <typename Ret, typename ...Args>
        static auto callMethodAndRead(
            sdbusplus::bus::bus& bus,
            const std::string& busName,
            const std::string& path,
            const std::string& interface,
            const std::string& method,
            Args&& ... args)
        {
            sdbusplus::message::message respMsg =
                    callMethod<Args...>(
                            bus,
                            busName,
                            path,
                            interface,
                            method,
                            std::forward<Args>(args)...);
            Ret resp;
            respMsg.read(resp);
            return resp;
        }

        /** @brief Invoke a method and read the response. */
        template <typename Ret, typename ...Args>
        static auto callMethodAndRead(
            const std::string& busName,
            const std::string& path,
            const std::string& interface,
            const std::string& method,
            Args&& ... args)
        {
            return callMethodAndRead<Ret>(
                    getBus(),
                    busName,
                    path,
                    interface,
                    method,
                    std::forward<Args>(args)...);
        }

        /** @brief Get subtree from the mapper. */
        static auto getSubTree(
            sdbusplus::bus::bus& bus,
            const std::string& path,
            const std::string& interface,
            int32_t depth)
        {
            using namespace std::literals::string_literals;

            using Path = std::string;
            using Intf = std::string;
            using Serv = std::string;
            using Intfs = std::vector<Intf>;
            using Objects = std::map<Path, std::map<Serv, Intfs>>;
            Intfs intfs = {interface};

            auto mapperResp = callMethodAndRead<Objects>(
                    bus,
                    "xyz.openbmc_project.ObjectMapper"s,
                    "/xyz/openbmc_project/object_mapper"s,
                    "xyz.openbmc_project.ObjectMapper"s,
                    "GetSubTree"s,
                    path,
                    depth,
                    intfs);

            if (mapperResp.empty())
            {
                phosphor::logging::log<phosphor::logging::level::ERR>(
                        "Empty response from mapper GetSubTree",
                        phosphor::logging::entry("SUBTREE=%s", path.c_str()),
                        phosphor::logging::entry(
                                "INTERFACE=%s", interface.c_str()),
                        phosphor::logging::entry("DEPTH=%u", depth));
                phosphor::logging::elog<detail::errors::InternalFailure>();
            }
            return mapperResp;
        }

        /** @brief Get service from the mapper. */
        static auto getService(
            sdbusplus::bus::bus& bus,
            const std::string& path,
            const std::string& interface)
        {
            using namespace std::literals::string_literals;
            using GetObject = std::map<std::string, std::vector<std::string>>;

            try
            {
                auto mapperResp = callMethodAndRead<GetObject>(
                        bus,
                        "xyz.openbmc_project.ObjectMapper"s,
                        "/xyz/openbmc_project/object_mapper"s,
                        "xyz.openbmc_project.ObjectMapper"s,
                        "GetObject"s,
                        path,
                        GetObject::mapped_type{interface});

                if (mapperResp.empty())
                {
                    //Should never happen.  A missing object would fail
                    //in callMethodAndRead()
                    phosphor::logging::log<phosphor::logging::level::ERR>(
                            "Empty mapper response on service lookup");
                    throw DBusServiceError{path, interface};
                }
                return mapperResp.begin()->first;
            }
            catch (DBusMethodError& e)
            {
                throw DBusServiceError{path, interface};
            }
        }

        /** @brief Get service from the mapper. */
        static auto getService(
            const std::string& path,
            const std::string& interface)
        {
            return getService(
                    getBus(),
                    path,
                    interface);
        }

        /** @brief Get a property with mapper lookup. */
        template <typename Property>
        static auto getProperty(
            sdbusplus::bus::bus& bus,
            const std::string& path,
            const std::string& interface,
            const std::string& property)
        {
            using namespace std::literals::string_literals;

            auto msg = callMethod(
                    bus,
                    getService(bus, path, interface),
                    path,
                    "org.freedesktop.DBus.Properties"s,
                    "Get"s,
                    interface,
                    property);
            sdbusplus::message::variant<Property> value;
            msg.read(value);
            return value.template get<Property>();
        }

        /** @brief Get a property with mapper lookup. */
        template <typename Property>
        static auto getProperty(
            const std::string& path,
            const std::string& interface,
            const std::string& property)
        {
            return getProperty<Property>(
                    getBus(),
                    path,
                    interface,
                    property);
        }

        /** @brief Get a property variant with mapper lookup. */
        template <typename Variant>
        static auto getPropertyVariant(
            sdbusplus::bus::bus& bus,
            const std::string& path,
            const std::string& interface,
            const std::string& property)
        {
            using namespace std::literals::string_literals;

            auto msg = callMethod(
                    bus,
                    getService(bus, path, interface),
                    path,
                    "org.freedesktop.DBus.Properties"s,
                    "Get"s,
                    interface,
                    property);
            Variant value;
            msg.read(value);
            return value;
        }

        /** @brief Get a property variant with mapper lookup. */
        template <typename Variant>
        static auto getPropertyVariant(
            const std::string& path,
            const std::string& interface,
            const std::string& property)
        {
            return getPropertyVariant<Variant>(
                    getBus(),
                    path,
                    interface,
                    property);
        }

        /** @brief Get a property without mapper lookup. */
        template <typename Property>
        static auto getProperty(
            sdbusplus::bus::bus& bus,
            const std::string& service,
            const std::string& path,
            const std::string& interface,
            const std::string& property)
        {
            using namespace std::literals::string_literals;

            auto msg = callMethod(
                    bus,
                    service,
                    path,
                    "org.freedesktop.DBus.Properties"s,
                    "Get"s,
                    interface,
                    property);
            sdbusplus::message::variant<Property> value;
            msg.read(value);
            return value.template get<Property>();
        }

        /** @brief Get a property without mapper lookup. */
        template <typename Property>
        static auto getProperty(
            const std::string& service,
            const std::string& path,
            const std::string& interface,
            const std::string& property)
        {
            return getProperty<Property>(
                    getBus(),
                    service,
                    path,
                    interface,
                    property);
        }

        /** @brief Get a property variant without mapper lookup. */
        template <typename Variant>
        static auto getPropertyVariant(
            sdbusplus::bus::bus& bus,
            const std::string& service,
            const std::string& path,
            const std::string& interface,
            const std::string& property)
        {
            using namespace std::literals::string_literals;

            auto msg = callMethod(
                    bus,
                    service,
                    path,
                    "org.freedesktop.DBus.Properties"s,
                    "Get"s,
                    interface,
                    property);
            Variant value;
            msg.read(value);
            return value;
        }

        /** @brief Get a property variant without mapper lookup. */
        template <typename Variant>
        static auto getPropertyVariant(
            const std::string& service,
            const std::string& path,
            const std::string& interface,
            const std::string& property)
        {
            return getPropertyVariant<Variant>(
                    getBus(),
                    service,
                    path,
                    interface,
                    property);
        }

        /** @brief Set a property with mapper lookup. */
        template <typename Property>
        static void setProperty(
            sdbusplus::bus::bus& bus,
            const std::string& path,
            const std::string& interface,
            const std::string& property,
            Property&& value)
        {
            using namespace std::literals::string_literals;

            sdbusplus::message::variant<Property> varValue(
                    std::forward<Property>(value));

            callMethod(
                    bus,
                    getService(bus, path, interface),
                    path,
                    "org.freedesktop.DBus.Properties"s,
                    "Set"s,
                    interface,
                    property,
                    varValue);
        }

        /** @brief Set a property with mapper lookup. */
        template <typename Property>
        static void setProperty(
            const std::string& path,
            const std::string& interface,
            const std::string& property,
            Property&& value)
        {
            return setProperty(
                    getBus(),
                    path,
                    interface,
                    property,
                    std::forward<Property>(value));
        }

        /** @brief Set a property without mapper lookup. */
        template <typename Property>
        static void setProperty(
            sdbusplus::bus::bus& bus,
            const std::string& service,
            const std::string& path,
            const std::string& interface,
            const std::string& property,
            Property&& value)
        {
            using namespace std::literals::string_literals;

            sdbusplus::message::variant<Property> varValue(
                    std::forward<Property>(value));

            callMethod(
                    bus,
                    service,
                    path,
                    "org.freedesktop.DBus.Properties"s,
                    "Set"s,
                    interface,
                    property,
                    varValue);
        }

        /** @brief Set a property without mapper lookup. */
        template <typename Property>
        static void setProperty(
            const std::string& service,
            const std::string& path,
            const std::string& interface,
            const std::string& property,
            Property&& value)
        {
            return setProperty(
                    getBus(),
                    service,
                    path,
                    interface,
                    property,
                    std::forward<Property>(value));
        }

        /** @brief Invoke method with mapper lookup. */
        template <typename ...Args>
        static auto lookupAndCallMethod(
            sdbusplus::bus::bus& bus,
            const std::string& path,
            const std::string& interface,
            const std::string& method,
            Args&& ... args)
        {
            return callMethod(
                    bus,
                    getService(bus, path, interface),
                    path,
                    interface,
                    method,
                    std::forward<Args>(args)...);
        }

        /** @brief Invoke method with mapper lookup. */
        template <typename ...Args>
        static auto lookupAndCallMethod(
            const std::string& path,
            const std::string& interface,
            const std::string& method,
            Args&& ... args)
        {
            return lookupAndCallMethod(
                    getBus(),
                    path,
                    interface,
                    method,
                    std::forward<Args>(args)...);
        }

        /** @brief Invoke method and read with mapper lookup. */
        template <typename Ret, typename ...Args>
        static auto lookupCallMethodAndRead(
            sdbusplus::bus::bus& bus,
            const std::string& path,
            const std::string& interface,
            const std::string& method,
            Args&& ... args)
        {
            return callMethodAndRead(
                    bus,
                    getService(bus, path, interface),
                    path,
                    interface,
                    method,
                    std::forward<Args>(args)...);
        }

        /** @brief Invoke method and read with mapper lookup. */
        template <typename Ret, typename ...Args>
        static auto lookupCallMethodAndRead(
            const std::string& path,
            const std::string& interface,
            const std::string& method,
            Args&& ... args)
        {
            return lookupCallMethodAndRead<Ret>(
                    getBus(),
                    path,
                    interface,
                    method,
                    std::forward<Args>(args)...);
        }

        /** @brief Invoke a method and return without checking for error. */
        template <typename ...Args>
        static auto callMethodAndReturn(
            sdbusplus::bus::bus& bus,
            const std::string& busName,
            const std::string& path,
            const std::string& interface,
            const std::string& method,
            Args&& ... args)
        {
            auto reqMsg = bus.new_method_call(
                    busName.c_str(),
                    path.c_str(),
                    interface.c_str(),
                    method.c_str());
            reqMsg.append(std::forward<Args>(args)...);
            auto respMsg = bus.call(reqMsg);

            return respMsg;
        }
};

} // namespace util
} // namespace fan
} // namespace phosphor