svc: Handle memory writing explicitly within QueryProcessMemory

Moves the memory writes directly into QueryProcessMemory instead of
letting the wrapper function do it. It would be inaccurate to allow the
handler to do it because there's cases where memory shouldn't even be
written to. For example, if the given process handle is invalid.

HOWEVER, if the memory writing is within the wrapper, then we have no
control over if these memory writes occur, meaning in an error case, 68
bytes of memory randomly get trashed with zeroes, 64 of those being
written to wherever the memory info address points to, and the remaining
4 being written wherever the page info address points to.

One solution in this case would be to just conditionally check within
the handler itself, but this is kind of smelly, given the handler
shouldn't be performing conditional behavior itself, it's a behavior of
the managed function. In other words, if you remove the handler from the
equation entirely, does the function still retain its proper behavior?
In this case, no.

Now, we don't potentially trash memory from this function if an invalid
query is performed.

2 files changed, 22 insertions, 26 deletions

diff --git a/src/core/hle/kernel/svc.cpp b/src/core/hle/kernel/svc.cpp
index 8b079bc40..a1ecc4540 100644
--- a/src/core/hle/kernel/svc.cpp
+++ b/src/core/hle/kernel/svc.cpp
@@ -35,6 +35,7 @@
 #include "core/hle/lock.h"
 #include "core/hle/result.h"
 #include "core/hle/service/service.h"
+#include "core/memory.h"
 
 namespace Kernel {
 namespace {
@@ -1066,9 +1067,8 @@ static ResultCode UnmapSharedMemory(Handle shared_memory_handle, VAddr addr, u64
     return shared_memory->Unmap(*current_process, addr);
 }
 
-/// Query process memory
-static ResultCode QueryProcessMemory(MemoryInfo* memory_info, PageInfo* /*page_info*/,
-                                     Handle process_handle, u64 address) {
+static ResultCode QueryProcessMemory(VAddr memory_info_address, VAddr page_info_address,
+                                     Handle process_handle, VAddr address) {
     LOG_TRACE(Kernel_SVC, "called process=0x{:08X} address={:X}", process_handle, address);
     const auto& handle_table = Core::CurrentProcess()->GetHandleTable();
     SharedPtr<Process> process = handle_table.Get<Process>(process_handle);
@@ -1079,16 +1079,29 @@ static ResultCode QueryProcessMemory(MemoryInfo* memory_info, PageInfo* /*page_i
     }
 
     const auto& vm_manager = process->VMManager();
-    const auto result = vm_manager.QueryMemory(address);
+    const MemoryInfo memory_info = vm_manager.QueryMemory(address);
+
+    Memory::Write64(memory_info_address, memory_info.base_address);
+    Memory::Write64(memory_info_address + 8, memory_info.size);
+    Memory::Write32(memory_info_address + 16, memory_info.state);
+    Memory::Write32(memory_info_address + 20, memory_info.attributes);
+    Memory::Write32(memory_info_address + 24, memory_info.permission);
+
+    // Page info appears to be currently unused by the kernel and is always set to zero.
+    Memory::Write32(page_info_address, 0);
 
-    *memory_info = result;
     return RESULT_SUCCESS;
 }
 
-/// Query memory
-static ResultCode QueryMemory(MemoryInfo* memory_info, PageInfo* page_info, VAddr addr) {
-    LOG_TRACE(Kernel_SVC, "called, addr={:X}", addr);
-    return QueryProcessMemory(memory_info, page_info, CurrentProcess, addr);
+static ResultCode QueryMemory(VAddr memory_info_address, VAddr page_info_address,
+                              VAddr query_address) {
+    LOG_TRACE(Kernel_SVC,
+              "called, memory_info_address=0x{:016X}, page_info_address=0x{:016X}, "
+              "query_address=0x{:016X}",
+              memory_info_address, page_info_address, query_address);
+
+    return QueryProcessMemory(memory_info_address, page_info_address, CurrentProcess,
+                              query_address);
 }
 
 /// Exits the current process
diff --git a/src/core/hle/kernel/svc_wrap.h b/src/core/hle/kernel/svc_wrap.h
index 27a11d82e..f03b5438b 100644
--- a/src/core/hle/kernel/svc_wrap.h
+++ b/src/core/hle/kernel/svc_wrap.h
@@ -7,9 +7,7 @@
 #include "common/common_types.h"
 #include "core/arm/arm_interface.h"
 #include "core/core.h"
-#include "core/hle/kernel/vm_manager.h"
 #include "core/hle/result.h"
-#include "core/memory.h"
 
 namespace Kernel {
 
@@ -191,21 +189,6 @@ void SvcWrap() {
     FuncReturn(retval);
 }
 
-template <ResultCode func(MemoryInfo*, PageInfo*, u64)>
-void SvcWrap() {
-    MemoryInfo memory_info = {};
-    PageInfo page_info = {};
-    u32 retval = func(&memory_info, &page_info, Param(2)).raw;
-
-    Memory::Write64(Param(0), memory_info.base_address);
-    Memory::Write64(Param(0) + 8, memory_info.size);
-    Memory::Write32(Param(0) + 16, memory_info.state);
-    Memory::Write32(Param(0) + 20, memory_info.attributes);
-    Memory::Write32(Param(0) + 24, memory_info.permission);
-
-    FuncReturn(retval);
-}
-
 template <ResultCode func(u32*, u64, u64, u32)>
 void SvcWrap() {
     u32 param_1 = 0;