prepo: Implement GetSystemSessionId and add perms (#2014)

* prepo: Implement GetSystemSessionId and add perms

* address feedbacks

Ryujinx.HLE/HOS/Services/Prepo/IPrepoService.cs

@@ -5,16 +5,25 @@ using Ryujinx.Common.Logging;
 using Ryujinx.Common.Utilities;
 using Ryujinx.HLE.HOS.Services.Account.Acc;
 using Ryujinx.HLE.Utilities;
+using System;
 using System.Text;
 
 namespace Ryujinx.HLE.HOS.Services.Prepo
 {
-    [Service("prepo:a")]
-    [Service("prepo:a2")]
-    [Service("prepo:u")]
+    [Service("prepo:a",  PrepoServicePermissionLevel.Admin)] // 1.0.0-5.1.0
+    [Service("prepo:a2", PrepoServicePermissionLevel.Admin)] // 6.0.0+
+    [Service("prepo:m",  PrepoServicePermissionLevel.Manager)]
+    [Service("prepo:u",  PrepoServicePermissionLevel.User)]
+    [Service("prepo:s",  PrepoServicePermissionLevel.System)]
     class IPrepoService : IpcService
     {
-        public IPrepoService(ServiceCtx context) { }
+        private PrepoServicePermissionLevel _permission;
+        private ulong _systemSessionId;
+
+        public IPrepoService(ServiceCtx context, PrepoServicePermissionLevel permission)
+        {
+            _permission = permission;
+        }
 
         [Command(10100)] // 1.0.0-5.1.0
         [Command(10102)] // 6.0.0-9.2.0
@@ -22,6 +31,11 @@ namespace Ryujinx.HLE.HOS.Services.Prepo
         // SaveReport(u64, pid, buffer<u8, 9>, buffer<bytes, 5>)
         public ResultCode SaveReport(ServiceCtx context)
         {
+            if (((int)_permission & 1) == 0)
+            {
+                return ResultCode.PermissionDenied;
+            }
+
             // We don't care about the differences since we don't use the play report.
             return ProcessReport(context, withUserID: false);
         }
@@ -32,6 +46,11 @@ namespace Ryujinx.HLE.HOS.Services.Prepo
         // SaveReportWithUser(nn::account::Uid, u64, pid, buffer<u8, 9>, buffer<bytes, 5>)
         public ResultCode SaveReportWithUser(ServiceCtx context)
         {
+            if (((int)_permission & 1) == 0)
+            {
+                return ResultCode.PermissionDenied;
+            }
+
             // We don't care about the differences since we don't use the play report.
             return ProcessReport(context, withUserID: true);
         }
@@ -57,6 +76,29 @@ namespace Ryujinx.HLE.HOS.Services.Prepo
             return ResultCode.Success;
         }
 
+        [Command(10400)] // 9.0.0+
+        // GetSystemSessionId() -> u64
+        public ResultCode GetSystemSessionId(ServiceCtx context)
+        {
+            if (((int)_permission & 1) == 0)
+            {
+                return ResultCode.PermissionDenied;
+            }
+
+            if (_systemSessionId == 0)
+            {
+                byte[] randomBuffer = new byte[8];
+
+                new Random().NextBytes(randomBuffer);
+
+                _systemSessionId = BitConverter.ToUInt64(randomBuffer, 0);
+            }
+
+            context.ResponseData.Write(_systemSessionId);
+
+            return ResultCode.Success;
+        }
+
         private ResultCode ProcessReport(ServiceCtx context, bool withUserID)
         {
             UserId userId   = withUserID ? context.RequestData.ReadStruct<UserId>() : new UserId();

Ryujinx.HLE/HOS/Services/Prepo/ResultCode.cs

@@ -7,9 +7,9 @@ namespace Ryujinx.HLE.HOS.Services.Prepo
 
         Success = 0,
 
-        InvalidArgument   = (1 << ErrorCodeShift) | ModuleId,
-        InvalidState      = (5 << ErrorCodeShift) | ModuleId,
-        InvalidBufferSize = (9 << ErrorCodeShift) | ModuleId,
-        Unknown1          = (90 << ErrorCodeShift) | ModuleId
+        InvalidArgument   = (1  << ErrorCodeShift) | ModuleId,
+        InvalidState      = (5  << ErrorCodeShift) | ModuleId,
+        InvalidBufferSize = (9  << ErrorCodeShift) | ModuleId,
+        PermissionDenied  = (90 << ErrorCodeShift) | ModuleId
     }
 }

Ryujinx.HLE/HOS/Services/Prepo/Types/PrepoServicePermissionLevel.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace Ryujinx.HLE.HOS.Services.Prepo
+{
+    enum PrepoServicePermissionLevel
+    {
+        Admin   = -1,
+        User    = 1,
+        System  = 2,
+        Manager = 6
+    }
+}