DCMI : Implement Get System GUID command

Implemented IPMI Get System GUID command. It reads data
from the DBUS object which is in RFC4122(MSB) format and
converts to LSB format and returns.

Resolves openbmc/openbmc#2620

Change-Id: I95f0aa596695bf1f903b4c2cc1d64df80bdd3de9
Signed-off-by: Marri Devender Rao <devenrao@in.ibm.com>

2 files changed, 75 insertions, 0 deletions

diff --git a/apphandler.cpp b/apphandler.cpp
index 4b00065..69ea4e4 100644
--- a/apphandler.cpp
+++ b/apphandler.cpp
@@ -31,6 +31,11 @@ constexpr auto app_obj = "/org/openbmc/NetworkManager/Interface";
 constexpr auto app_ifc = "org.openbmc.NetworkManager";
 constexpr auto app_nwinterface = "eth0";
 
+constexpr auto bmc_interface = "xyz.openbmc_project.Inventory.Item.Bmc";
+constexpr auto bmc_guid_interface = "xyz.openbmc_project.Common.UUID";
+constexpr auto bmc_guid_property = "UUID";
+constexpr auto bmc_guid_len = 16;
+
 void register_netfn_app_functions() __attribute__((constructor));
 
 using namespace phosphor::logging;
@@ -426,6 +431,71 @@ ipmi_ret_t ipmi_app_wildcard_handler(ipmi_netfn_t netfn, ipmi_cmd_t cmd,
     return rc;
 }
 
+ipmi_ret_t ipmi_app_get_sys_guid(ipmi_netfn_t netfn, ipmi_cmd_t cmd,
+                             ipmi_request_t request, ipmi_response_t response,
+                             ipmi_data_len_t data_len, ipmi_context_t context)
+
+{
+    ipmi_ret_t rc = IPMI_CC_OK;
+    sdbusplus::bus::bus bus{ipmid_get_sd_bus_connection()};
+
+    try
+    {
+        // Get the Inventory object implementing BMC interface
+        ipmi::DbusObjectInfo bmcObject =
+            ipmi::getDbusObject(bus, bmc_interface);
+
+        // Read UUID property value from bmcObject
+        // UUID is in RFC4122 format Ex: 61a39523-78f2-11e5-9862-e6402cfc3223
+        auto variant = ipmi::getDbusProperty(
+                bus, bmcObject.second, bmcObject.first, bmc_guid_interface,
+                bmc_guid_property);
+        std::string guidProp = variant.get<std::string>();
+
+        // Erase "-" characters from the property value
+        guidProp.erase(std::remove(guidProp.begin(), guidProp.end(), '-'),
+                guidProp.end());
+
+        auto guidPropLen = guidProp.length();
+        // Validate UUID data
+        // Divide by 2 as 1 byte is built from 2 chars
+        if ( (guidPropLen <=0) || ((guidPropLen/2) != bmc_guid_len) )
+
+        {
+            log<level::ERR>("Invalid UUID property value",
+                    entry("UUID_LENGTH=%d", guidPropLen));
+            return IPMI_CC_RESPONSE_ERROR;
+        }
+
+        // Convert data in RFC4122(MSB) format to LSB format
+        // Get 2 characters at a time as 1 byte is built from 2 chars and
+        // convert to hex byte
+        // TODO: Data printed for GUID command is not as per the
+        // GUID format defined in IPMI specification 2.0 section 20.8
+        // Ticket raised: https://sourceforge.net/p/ipmitool/bugs/501/
+        uint8_t respGuid[bmc_guid_len];
+        for (size_t i = 0, respLoc = (bmc_guid_len - 1);
+            i < guidPropLen && respLoc >= 0; i += 2, respLoc--)
+        {
+            auto value = static_cast<uint8_t>(
+                    std::stoi(guidProp.substr(i, 2).c_str(), NULL, 16));
+            respGuid[respLoc] = value;
+        }
+
+        *data_len = bmc_guid_len;
+        memcpy(response, &respGuid, bmc_guid_len);
+    }
+    catch (const InternalFailure& e)
+    {
+        log<level::ERR>("Failed in reading BMC UUID property",
+                        entry("INTERFACE=%s", bmc_interface),
+                        entry("PROPERTY_INTERFACE=%s", bmc_guid_interface),
+                        entry("PROPERTY=%s", bmc_guid_property));
+        return IPMI_CC_UNSPECIFIED_ERROR;
+    }
+    return rc;
+}
+
 void register_netfn_app_functions()
 {
     // <Get BT Interface Capabilities>
@@ -484,6 +554,10 @@ void register_netfn_app_functions()
     ipmi_register_callback(NETFUN_APP, IPMI_CMD_GET_CHAN_INFO, NULL, ipmi_app_channel_info,
                            PRIVILEGE_USER);
 
+    // <Get System GUID Command>
+    printf("Registering NetFn:[0x%X], Cmd:[0x%X]\n",NETFUN_APP, IPMI_CMD_GET_SYS_GUID);
+    ipmi_register_callback(NETFUN_APP, IPMI_CMD_GET_SYS_GUID, NULL, ipmi_app_get_sys_guid,
+                           PRIVILEGE_USER);
     return;
 }
 
diff --git a/apphandler.h b/apphandler.h
index 72997d9..89bb51b 100644
--- a/apphandler.h
+++ b/apphandler.h
@@ -14,6 +14,7 @@ enum ipmi_netfn_app_cmds
     IPMI_CMD_RESET_WD               = 0x22,
     IPMI_CMD_SET_WD                 = 0x24,
     IPMI_CMD_GET_CAP_BIT            = 0x36,
+    IPMI_CMD_GET_SYS_GUID           = 0x37,
     IPMI_CMD_SET_CHAN_ACCESS        = 0x40,
     IPMI_CMD_GET_CHANNEL_ACCESS     = 0x41,
     IPMI_CMD_GET_CHAN_INFO          = 0x42,