kernel/svc: Implement the resource limit svcGetInfo option

Allows a process to register the resource limit as part of its handle
table.

src/core/hle/kernel/handle_table.h

@@ -13,6 +13,7 @@
 namespace Kernel {
 
 enum KernelHandle : Handle {
+    InvalidHandle = 0,
     CurrentThread = 0xFFFF8000,
     CurrentProcess = 0xFFFF8001,
 };

src/core/hle/kernel/process.cpp

@@ -44,6 +44,10 @@ SharedPtr<Process> Process::Create(KernelCore& kernel, std::string&& name) {
     return process;
 }
 
+SharedPtr<ResourceLimit> Process::GetResourceLimit() const {
+    return resource_limit;
+}
+
 void Process::LoadFromMetadata(const FileSys::ProgramMetadata& metadata) {
     program_id = metadata.GetTitleID();
     is_64bit_process = metadata.Is64BitProgram();

src/core/hle/kernel/process.h

@@ -171,14 +171,7 @@ public:
     }
 
     /// Gets the resource limit descriptor for this process
-    ResourceLimit& GetResourceLimit() {
+    SharedPtr<ResourceLimit> GetResourceLimit() const;
-        return *resource_limit;
-    }
-
-    /// Gets the resource limit descriptor for this process
-    const ResourceLimit& GetResourceLimit() const {
-        return *resource_limit;
-    }
 
     /// Gets the default CPU ID for this process
     u8 GetDefaultProcessorID() const {

src/core/hle/kernel/svc.cpp

@@ -663,7 +663,7 @@ static ResultCode GetInfo(u64* result, u64 info_id, u64 handle, u64 info_sub_id)
         TotalMemoryUsage = 6,
         TotalHeapUsage = 7,
         IsCurrentProcessBeingDebugged = 8,
-        ResourceHandleLimit = 9,
+        RegisterResourceLimit = 9,
         IdleTickCount = 10,
         RandomEntropy = 11,
         PerformanceCounter = 0xF0000002,
@@ -787,6 +787,33 @@ static ResultCode GetInfo(u64* result, u64 info_id, u64 handle, u64 info_sub_id)
         *result = 0;
         return RESULT_SUCCESS;
 
+    case GetInfoType::RegisterResourceLimit: {
+        if (handle != 0) {
+            return ERR_INVALID_HANDLE;
+        }
+
+        if (info_sub_id != 0) {
+            return ERR_INVALID_COMBINATION;
+        }
+
+        Process* const current_process = Core::CurrentProcess();
+        HandleTable& handle_table = current_process->GetHandleTable();
+        const auto resource_limit = current_process->GetResourceLimit();
+        if (!resource_limit) {
+            *result = KernelHandle::InvalidHandle;
+            // Yes, the kernel considers this a successful operation.
+            return RESULT_SUCCESS;
+        }
+
+        const auto table_result = handle_table.Create(resource_limit);
+        if (table_result.Failed()) {
+            return table_result.Code();
+        }
+
+        *result = *table_result;
+        return RESULT_SUCCESS;
+    }
+
     case GetInfoType::RandomEntropy:
         if (handle != 0) {
             LOG_ERROR(Kernel_SVC, "Process Handle is non zero, expected 0 result but got {:016X}",