Use systemd targets to track host states

Change-Id: I5ab174d945c1dfb265a02f9095d3eaeb0ba562db
Signed-off-by: Andrew Geissler <andrewg@us.ibm.com>

2 files changed, 91 insertions, 43 deletions

diff --git a/host_state_manager.cpp b/host_state_manager.cpp
index e16d0de..2d35886 100644
--- a/host_state_manager.cpp
+++ b/host_state_manager.cpp
@@ -17,11 +17,14 @@ namespace server = sdbusplus::xyz::openbmc_project::State::server;
 
 using namespace phosphor::logging;
 
+constexpr auto HOST_STATE_POWEROFF_TGT = "obmc-chassis-stop@0.target";
+constexpr auto HOST_STATE_POWERON_TGT = "obmc-chassis-start@0.target";
+
 /* Map a transition to it's systemd target */
 const std::map<server::Host::Transition,std::string> SYSTEMD_TARGET_TABLE =
 {
-        {server::Host::Transition::Off, "obmc-chassis-stop@0.target"},
-        {server::Host::Transition::On, "obmc-chassis-start@0.target"}
+        {server::Host::Transition::Off, HOST_STATE_POWEROFF_TGT},
+        {server::Host::Transition::On, HOST_STATE_POWERON_TGT}
 };
 
 constexpr auto SYSTEMD_SERVICE   = "org.freedesktop.systemd1";
@@ -33,12 +36,22 @@ constexpr auto SYSTEM_OBJ_PATH  = "/org/openbmc/managers/System";
 constexpr auto SYSTEM_INTERFACE = SYSTEM_SERVICE;
 
 /* Map a system state to the HostState */
-/* TODO:Issue 774 - Use systemd target signals to control host states */
 const std::map<std::string, server::Host::HostState> SYS_HOST_STATE_TABLE = {
         {"HOST_BOOTING", server::Host::HostState::Running},
         {"HOST_POWERED_OFF", server::Host::HostState::Off}
 };
 
+void Host::subscribeToSystemdSignals()
+{
+    auto method = this->bus.new_method_call(SYSTEMD_SERVICE,
+                                            SYSTEMD_OBJ_PATH,
+                                            SYSTEMD_INTERFACE,
+                                            "Subscribe");
+    this->bus.call_noreply(method);
+
+    return;
+}
+
 // TODO - Will be rewritten once sdbusplus client bindings are in place
 //        and persistent storage design is in place
 void Host::determineInitialState()
@@ -90,40 +103,49 @@ void Host::executeTransition(Transition tranReq)
     method.append(sysdUnit);
     method.append("replace");
 
-    this->bus.call(method);
+    this->bus.call_noreply(method);
 
     return;
 }
 
-int Host::handleSysStateChange(sd_bus_message *msg, void *usrData,
-                               sd_bus_error *retError)
+int Host::sysStateChangeSignal(sd_bus_message *msg, void *userData,
+                                  sd_bus_error *retError)
+{
+    return static_cast<Host*>(userData)->sysStateChange(msg, retError);
+}
+
+int Host::sysStateChange(sd_bus_message* msg,
+                         sd_bus_error* retError)
 {
-    const char *newState = nullptr;
+    uint32_t newStateID {};
+    sdbusplus::message::object_path newStateObjPath;
+    std::string newStateUnit{};
+    std::string newStateResult{};
+
     auto sdPlusMsg = sdbusplus::message::message(msg);
-    sdPlusMsg.read(newState);
+    //Read the msg and populate each variable
+    sdPlusMsg.read(newStateID, newStateObjPath, newStateUnit, newStateResult);
 
-    auto it = SYS_HOST_STATE_TABLE.find(newState);
-    if(it != SYS_HOST_STATE_TABLE.end())
+    if((newStateUnit == HOST_STATE_POWEROFF_TGT) &&
+       (newStateResult == "done"))
     {
-        // This is a state change we're interested in so process it
-        Host::HostState gotoState = it->second;
-        // Grab the host object instance from the userData
-        auto hostInst = static_cast<Host*>(usrData);
-        hostInst->currentHostState(gotoState);
+        log<level::INFO>("Recieved signal that host is off");
+        this->currentHostState(server::Host::HostState::Off);
 
         // Check if we need to start a new transition (i.e. a Reboot)
-        if((gotoState == server::Host::HostState::Off) &&
-           (hostInst->server::Host::requestedHostTransition() ==
-               Transition::Reboot))
+        if(this->server::Host::requestedHostTransition() ==
+               Transition::Reboot)
         {
             log<level::DEBUG>("Reached intermediate state, going to next");
-            hostInst->executeTransition(server::Host::Transition::On);
-        }
-        else
-        {
-            log<level::DEBUG>("Reached final state");
+            this->executeTransition(server::Host::Transition::On);
         }
     }
+    else if((newStateUnit == HOST_STATE_POWERON_TGT) &&
+            (newStateResult == "done"))
+     {
+         log<level::INFO>("Recieved signal that host is running");
+         this->currentHostState(server::Host::HostState::Running);
+     }
 
     return 0;
 }
diff --git a/host_state_manager.hpp b/host_state_manager.hpp
index 515409e..597efa5 100644
--- a/host_state_manager.hpp
+++ b/host_state_manager.hpp
@@ -36,11 +36,17 @@ class Host : public sdbusplus::server::object::object<
                     sdbusplus::xyz::openbmc_project::State::server::Host>(
                             bus, objPath, true),
                 bus(bus),
-                stateSignal(bus,
-                            "type='signal',member='GotoSystemState'",
-                            handleSysStateChange,
-                            this)
+                systemdSignals(bus,
+                               "type='signal',"
+                               "member='JobRemoved',"
+                               "path='/org/freedesktop/systemd1',"
+                               "interface='org.freedesktop.systemd1.Manager'",
+                                sysStateChangeSignal,
+                                this)
         {
+            // Enable systemd signals
+            subscribeToSystemdSignals();
+
             // Will throw exception on fail
             determineInitialState();
 
@@ -48,13 +54,6 @@ class Host : public sdbusplus::server::object::object<
             this->emit_object_added();
         }
 
-        /**
-         * @brief Determine initial host state and set internally
-         *
-         * @return Will throw exceptions on failure
-         **/
-        void determineInitialState();
-
         /** @brief Set value of HostTransition */
         Transition requestedHostTransition(Transition value) override;
 
@@ -62,6 +61,22 @@ class Host : public sdbusplus::server::object::object<
         HostState currentHostState(HostState value) override;
 
     private:
+        /**
+         * @brief subscribe to the systemd signals
+         *
+         * This object needs to capture when it's systemd targets complete
+         * so it can keep it's state updated
+         *
+         **/
+        void subscribeToSystemdSignals();
+
+        /**
+         * @brief Determine initial host state and set internally
+         *
+         * @return Will throw exceptions on failure
+         **/
+        void determineInitialState();
+
         /** @brief Execute the transition request
          *
          * This function assumes the state has been validated and the host
@@ -71,25 +86,36 @@ class Host : public sdbusplus::server::object::object<
          */
         void executeTransition(Transition tranReq);
 
-        /** @brief Callback function on system state changes
+        /** @brief Callback function on systemd state changes
          *
-         *  Check if the state is relevant to the Host and if so, update
-         *  corresponding host object's state
+         * Will just do a call into the appropriate object for processing
          *
-         * @param[in] msg        - Data associated with subscribed signal
-         * @param[in] userData   - Pointer to this object instance
-         * @param[in] retError   - Return error data
+         * @param[in]  msg       - Data associated with subscribed signal
+         * @param[in]  userData  - Pointer to this object instance
+         * @param[out] retError  - Not used but required with signal API
          *
          */
-        static int handleSysStateChange(sd_bus_message* msg,
+        static int sysStateChangeSignal(sd_bus_message* msg,
                                         void* userData,
                                         sd_bus_error* retError);
 
+        /** @brief Check if systemd state change is relevant to this object
+         *
+         * Instance specific interface to handle the detected systemd state
+         * change
+         *
+         * @param[in]  msg       - Data associated with subscribed signal
+         * @param[out] retError  - Not used but required with signal API
+         *
+         */
+        int sysStateChange(sd_bus_message* msg,
+                           sd_bus_error* retError);
+
         /** @brief Persistent sdbusplus DBus bus connection. */
         sdbusplus::bus::bus& bus;
 
-        /** @brief Used to subscribe to dbus system state changes */
-        sdbusplus::server::match::match stateSignal;
+        /** @brief Used to subscribe to dbus systemd signals **/
+        sdbusplus::server::match::match systemdSignals;
 };
 
 } // namespace manager