2 files changed, 103 insertions, 34 deletions

diff --git a/src/common/common_paths.h b/src/common/common_paths.h
index 95479a529..42e1a29c1 100644
--- a/src/common/common_paths.h
+++ b/src/common/common_paths.h
@@ -58,6 +58,9 @@
 #define DEBUGGER_CONFIG   "debugger.ini"
 #define LOGGER_CONFIG     "logger.ini"
 
+// Sys files
+#define SHARED_FONT       "shared_font.bin"
+
 // Files in the directory returned by GetUserPath(D_LOGS_IDX)
 #define MAIN_LOG "emu.log"
 
diff --git a/src/core/hle/service/apt_u.cpp b/src/core/hle/service/apt_u.cpp
index 4bb05ce40..181763724 100644
--- a/src/core/hle/service/apt_u.cpp
+++ b/src/core/hle/service/apt_u.cpp
@@ -4,10 +4,12 @@
 
 
 #include "common/common.h"
+#include "common/file_util.h"
 
 #include "core/hle/hle.h"
 #include "core/hle/kernel/event.h"
 #include "core/hle/kernel/mutex.h"
+#include "core/hle/kernel/shared_memory.h"
 #include "apt_u.h"
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -15,7 +17,19 @@
 
 namespace APT_U {
 
+// Address used for shared font (as observed on HW)
+// TODO(bunnei): This is the hard-coded address where we currently dump the shared font from via
+// https://github.com/citra-emu/3dsutils. This is technically a hack, and will not work at any
+// address other than 0x18000000 due to internal pointers in the shared font dump that would need to
+// be relocated. This might be fixed by dumping the shared font @ address 0x00000000 and then
+// correctly mapping it in Citra, however we still do not understand how the mapping is determined.
+static const VAddr SHARED_FONT_VADDR = 0x18000000;
+
+// Handle to shared memory region designated to for shared system font
+static Handle shared_font_mem = 0;
+
 static Handle lock_handle = 0;
+static std::vector<u8> shared_font;
 
 /// Signals used by APT functions
 enum class SignalType : u32 {
@@ -84,18 +98,18 @@ void InquireNotification(Service::Interface* self) {
  * state so that this command will return an error if this command is used again if parameters were
  * not set again. This is called when the second Initialize event is triggered. It returns a signal
  * type indicating why it was triggered.
- * Inputs:
- * 1 : AppID
- * 2 : Parameter buffer size, max size is 0x1000
- * Outputs:
- * 1 : Result of function, 0 on success, otherwise error code
- * 2 : Unknown, for now assume AppID of the process which sent these parameters
- * 3 : Unknown, for now assume Signal type
- * 4 : Actual parameter buffer size, this is <= to the the input size
- * 5 : Value
- * 6 : Handle from the source process which set the parameters, likely used for shared memory
- * 7 : Size
- * 8 : Output parameter buffer ptr
+ *  Inputs:
+ *      1 : AppID
+ *      2 : Parameter buffer size, max size is 0x1000
+ *  Outputs:
+ *      1 : Result of function, 0 on success, otherwise error code
+ *      2 : Unknown, for now assume AppID of the process which sent these parameters
+ *      3 : Unknown, for now assume Signal type
+ *      4 : Actual parameter buffer size, this is <= to the the input size
+ *      5 : Value
+ *      6 : Handle from the source process which set the parameters, likely used for shared memory
+ *      7 : Size
+ *      8 : Output parameter buffer ptr
  */
 void ReceiveParameter(Service::Interface* self) {
     u32* cmd_buff = Service::GetCommandBuffer();
@@ -115,18 +129,18 @@ void ReceiveParameter(Service::Interface* self) {
  * APT_U::GlanceParameter service function. This is exactly the same as APT_U::ReceiveParameter
  * (except for the word value prior to the output handle), except this will not clear the flag
  * (except when responseword[3]==8 || responseword[3]==9) in NS state.
- * Inputs:
- * 1 : AppID
- * 2 : Parameter buffer size, max size is 0x1000
- * Outputs:
- * 1 : Result of function, 0 on success, otherwise error code
- * 2 : Unknown, for now assume AppID of the process which sent these parameters
- * 3 : Unknown, for now assume Signal type
- * 4 : Actual parameter buffer size, this is <= to the the input size
- * 5 : Value
- * 6 : Handle from the source process which set the parameters, likely used for shared memory
- * 7 : Size
- * 8 : Output parameter buffer ptr
+ *  Inputs:
+ *      1 : AppID
+ *      2 : Parameter buffer size, max size is 0x1000
+ *  Outputs:
+ *      1 : Result of function, 0 on success, otherwise error code
+ *      2 : Unknown, for now assume AppID of the process which sent these parameters
+ *      3 : Unknown, for now assume Signal type
+ *      4 : Actual parameter buffer size, this is <= to the the input size
+ *      5 : Value
+ *      6 : Handle from the source process which set the parameters, likely used for shared memory
+ *      7 : Size
+ *      8 : Output parameter buffer ptr
  */
 void GlanceParameter(Service::Interface* self) {
     u32* cmd_buff = Service::GetCommandBuffer();
@@ -146,14 +160,14 @@ void GlanceParameter(Service::Interface* self) {
 
 /**
  * APT_U::AppletUtility service function
- * Inputs:
- * 1 : Unknown, but clearly used for something
- * 2 : Buffer 1 size (purpose is unknown)
- * 3 : Buffer 2 size (purpose is unknown)
- * 5 : Buffer 1 address (purpose is unknown)
- * 65 : Buffer 2 address (purpose is unknown)
- * Outputs:
- * 1 : Result of function, 0 on success, otherwise error code
+ *  Inputs:
+ *      1 : Unknown, but clearly used for something
+ *      2 : Buffer 1 size (purpose is unknown)
+ *      3 : Buffer 2 size (purpose is unknown)
+ *      5 : Buffer 1 address (purpose is unknown)
+ *      65 : Buffer 2 address (purpose is unknown)
+ *  Outputs:
+ *      1 : Result of function, 0 on success, otherwise error code
  */
 void AppletUtility(Service::Interface* self) {
     u32* cmd_buff = Service::GetCommandBuffer();
@@ -172,6 +186,34 @@ void AppletUtility(Service::Interface* self) {
              buffer1_addr, buffer2_addr);
 }
 
+/**
+ * APT_U::GetSharedFont service function
+ *  Outputs:
+ *      1 : Result of function, 0 on success, otherwise error code
+ *      2 : Virtual address of where shared font will be loaded in memory
+ *      4 : Handle to shared font memory
+ */
+void GetSharedFont(Service::Interface* self) {
+    DEBUG_LOG(KERNEL, "called");
+
+    u32* cmd_buff = Service::GetCommandBuffer();
+
+    if (!shared_font.empty()) {
+        // TODO(bunnei): This function shouldn't copy the shared font every time it's called.
+        // Instead, it should probably map the shared font as RO memory. We don't currently have
+        // an easy way to do this, but the copy should be sufficient for now.
+        memcpy(Memory::GetPointer(SHARED_FONT_VADDR), shared_font.data(), shared_font.size());
+
+        cmd_buff[0] = 0x00440082;
+        cmd_buff[1] = 0; // No error
+        cmd_buff[2] = SHARED_FONT_VADDR;
+        cmd_buff[4] = shared_font_mem;
+    } else {
+        cmd_buff[1] = -1; // Generic error (not really possible to verify this on hardware)
+        ERROR_LOG(KERNEL, "called, but %s has not been loaded!", SHARED_FONT);
+    }
+}
+
 const Interface::FunctionInfo FunctionTable[] = {
     {0x00010040, GetLockHandle,         "GetLockHandle"},
     {0x00020080, Initialize,            "Initialize"},
@@ -240,7 +282,7 @@ const Interface::FunctionInfo FunctionTable[] = {
     {0x00410040, nullptr,               "ReceiveCaptureBufferInfo"},
     {0x00420080, nullptr,               "SleepSystem"},
     {0x00430040, nullptr,               "NotifyToWait"},
-    {0x00440000, nullptr,               "GetSharedFont"},
+    {0x00440000, GetSharedFont,         "GetSharedFont"},
     {0x00450040, nullptr,               "GetWirelessRebootInfo"},
     {0x00460104, nullptr,               "Wrap"},
     {0x00470104, nullptr,               "Unwrap"},
@@ -259,9 +301,33 @@ const Interface::FunctionInfo FunctionTable[] = {
 // Interface class
 
 Interface::Interface() {
-    Register(FunctionTable, ARRAY_SIZE(FunctionTable));
+    // Load the shared system font (if available).
+    // The expected format is a decrypted, uncompressed BCFNT file with the 0x80 byte header
+    // generated by the APT:U service. The best way to get is by dumping it from RAM. We've provided
+    // a homebrew app to do this: https://github.com/citra-emu/3dsutils. Put the resulting file
+    // "shared_font.bin" in the Citra "sysdata" directory.
+
+    shared_font.clear();
+    std::string filepath = FileUtil::GetUserPath(D_SYSDATA_IDX) + SHARED_FONT;
+
+    FileUtil::CreateFullPath(filepath); // Create path if not already created
+    FileUtil::IOFile file(filepath, "rb");
+
+    if (file.IsOpen()) {
+        // Read shared font data
+        shared_font.resize(file.GetSize());
+        file.ReadBytes(shared_font.data(), file.GetSize());
+
+        // Create shared font memory object
+        shared_font_mem = Kernel::CreateSharedMemory("APT_U:shared_font_mem");
+    } else {
+        WARN_LOG(KERNEL, "Unable to load shared font: %s", filepath.c_str());
+        shared_font_mem = 0;
+    }
 
     lock_handle = 0;
+
+    Register(FunctionTable, ARRAY_SIZE(FunctionTable));
 }
 
 Interface::~Interface() {