phosphor-state-manager: Support multi-host for persist files

phosphor-host-state-manager and phosphor-chassis-state-manager store
informations in files then restore that on service starting.
Since state-managers already change to multi-host now, information
should store into different files from each service instance.

forbackward capability, if there are legacy persist file exist,
rename it to the new file format of instance ;0',i.e, rename files:
'requestedHostTransition' to 'host0-PersistData',
'POHCounter' to 'chassis-POHCounter',
'chassisStateChangeTime' to 'chassis0-StateChangeTime'

Changes:
a.phosphor-host-state-manager:
'/var/lib/phosphor-state-manager/requestedHostTransition'
this file not only store requestedHostTransition now,
rename to PersistData and add host-N prefix for each service.
For example, bus xyz.openbmc_project.State.Host1 store data to
'/var/lib/phosphor-state-manager/host1-PersistData'
 xyz.openbmc_project.State.Host2 store date to
'/var/lib/phosphor-state-manager/host2-PersistData'

b.phosphor-chassis-state-manager:

There are two files to store informations
'/var/lib/phosphor-state-manager/POHCounter',
'/var/lib/phosphor-state-manager/chassisStateChangeTime'
change to:
'/var/lib/phosphor-state-manager/chassis1-POHCounter',
'/var/lib/phosphor-state-manager/chassis2-POHCounter'
...
'/var/lib/phosphor-state-manager/chassis1-StateChangeTime'
'/var/lib/phosphor-state-manager/chassis2-StateChangeTime'
...  for each service.

Tested on Bletchley HW,

set xyz.openbmc_project.State.Host1 RequestedHostTransition to On
'busctl set-property xyz.openbmc_project.State.Host1 /xyz/openbmc_project/state/host1
	xyz.openbmc_project.State.Host RequestedHostTransition s "xyz.openbmc_project.State.Host.Transition.On"'

This request will store in file:
'cat /var/lib/phosphor-state-manager/host1-PersistData'
{
    "value0": {
        "cereal_class_version": 1,
        "value0": "xyz.openbmc_project.State.Host.Transition.On",
        "value1": "xyz.openbmc_project.State.Boot.Progress.ProgressStages.Unspecified",
        "value2": "xyz.openbmc_project.State.OperatingSystem.Status.OSStatus.Inactive"
    }

restart xyz.openbmc_project.State.Host1~Host6 or reboot BMC, 'RequestedHostTransition' for host1 still "On"
'busctl get-property xyz.openbmc_project.State.Host1 /xyz/openbmc_project/state/host1
	xyz.openbmc_project.State.Host RequestedHostTransition'
s "xyz.openbmc_project.State.Host.Transition.On"
'RequestedHostTransition' of the rest 5 Hosts are default value  "xyz.openbmc_project.State.Host.Transition.Off"

Also, set POHCounter of xyz.openbmc_project.State.Chassis2
'busctl set-property xyz.openbmc_project.State.Chassis2	/xyz/openbmc_project/state/chassis2
	xyz.openbmc_project.State.PowerOnHours POHCounter u 5'
it will restore after service restart or BMC reboot,
'busctl get-property  xyz.openbmc_project.State.Chassis2 /xyz/openbmc_project/state/chassis2
	xyz.openbmc_project.State.PowerOnHours POHCounter'
u 5

Change-Id: I739c62707bb805e7c25f399a2fea06beee5543a0
Signed-off-by: Allen.Wang <Allen_Wang@quantatw.com>
diff --git a/host_state_manager_main.cpp b/host_state_manager_main.cpp
index b96cdbf..13c8f53 100644
--- a/host_state_manager_main.cpp
+++ b/host_state_manager_main.cpp
@@ -2,6 +2,7 @@
 
 #include "host_state_manager.hpp"
 
+#include <fmt/format.h>
 #include <getopt.h>
 
 #include <sdbusplus/bus.hpp>
@@ -11,6 +12,9 @@
 #include <filesystem>
 #include <iostream>
 
+constexpr auto LEGACY_HOST_STATE_PERSIST_PATH =
+    "/var/lib/phosphor-state-manager/requestedHostTransition";
+
 int main(int argc, char** argv)
 {
     size_t hostId = 0;
@@ -40,6 +44,22 @@
     auto hostBusName = std::string{HOST_BUSNAME} + std::to_string(hostId);
     auto objPathInst = std::string{HOST_OBJPATH} + std::to_string(hostId);
 
+    if (hostId == 0)
+    {
+        // Host State Manager was only support single-host and there only one
+        // file to store persist values, to support multi-host state management,
+        // each service instance access new file path format with prefix 'hostN'
+        // now.For backward compatibility if there is a legacy persist file
+        // exist, rename it to the new file format of host0.
+
+        fs::path legacyPath{LEGACY_HOST_STATE_PERSIST_PATH};
+        fs::path newPath{fmt::format(HOST_STATE_PERSIST_PATH, hostId)};
+        if (fs::exists(legacyPath))
+        {
+            fs::rename(legacyPath, newPath);
+        }
+    }
+
     // Add sdbusplus ObjectManager.
     sdbusplus::server::manager::manager objManager(bus, objPathInst.c_str());