Address review comments

Use more modern C++ style casts + std::array, clean up some log
messages, and rename some functions.

src/citra/default_ini.h

@@ -322,7 +322,7 @@ camera_inner_flip =
 
 [Miscellaneous]
 # A filter which removes logs below a certain logging level.
-# Examples: *:Debug Kernel.SVC:Trace Service:Critical
+# Examples: *:Debug Kernel.SVC:Trace Service.*:Critical
 log_filter = *:Info
 
 [Debugging]

src/core/gdbstub/hio.cpp

@@ -38,7 +38,7 @@ static bool HasPendingHioRequest() {
 /**
  * @return Whether the GDB stub is awaiting a reply from the client.
  */
-static bool WaitingForHioReply() {
+static bool IsWaitingForHioReply() {
     return current_hio_request_addr != 0 && request_status == Status::SentWaitingReply;
 }
 
@@ -60,8 +60,8 @@ void SetHioRequest(const VAddr addr) {
         return;
     }
 
-    if (WaitingForHioReply()) {
-        LOG_WARNING(Debug_GDBStub, "HIO requested while already in progress!");
+    if (IsWaitingForHioReply()) {
+        LOG_WARNING(Debug_GDBStub, "HIO requested while already in progress");
         return;
     }
 
@@ -79,9 +79,14 @@ void SetHioRequest(const VAddr addr) {
 
     memory.ReadBlock(*process, addr, &current_hio_request, sizeof(PackedGdbHioRequest));
 
-    std::string_view magic{current_hio_request.magic};
-    if (magic != "GDB") {
-        LOG_WARNING(Debug_GDBStub, "Invalid HIO request sent by application: magic '{}'", magic);
+    if (current_hio_request.magic != std::array{'G', 'D', 'B', '\0'}) {
+        std::string_view bad_magic{
+            std::begin(current_hio_request.magic),
+            std::end(current_hio_request.magic),
+        };
+        LOG_WARNING(Debug_GDBStub, "Invalid HIO request sent by application: bad magic '{}'",
+                    bad_magic);
+
         current_hio_request_addr = 0;
         current_hio_request = {};
         request_status = Status::NoRequest;
@@ -104,7 +109,7 @@ void SetHioRequest(const VAddr addr) {
 }
 
 void HandleHioReply(const u8* const command_buffer, const u32 command_length) {
-    if (!WaitingForHioReply()) {
+    if (!IsWaitingForHioReply()) {
         LOG_WARNING(Debug_GDBStub, "Got HIO reply but never sent a request");
         return;
     }
@@ -135,7 +140,7 @@ void HandleHioReply(const u8* const command_buffer, const u32 command_length) {
     Common::SplitString(command_str, ',', command_parts);
 
     if (command_parts.empty() || command_parts.size() > 3) {
-        LOG_WARNING(Debug_GDBStub, "unexpected reply packet size: {}", command_parts);
+        LOG_WARNING(Debug_GDBStub, "Unexpected reply packet size: {}", command_parts);
         SendErrorReply(EILSEQ);
         return;
     }
@@ -201,25 +206,30 @@ bool HandlePendingHioRequestPacket() {
         return false;
     }
 
-    if (WaitingForHioReply()) {
+    if (IsWaitingForHioReply()) {
         // We already sent it, continue waiting for a reply
         return true;
     }
 
-    std::string packet = fmt::format("F{}", current_hio_request.function_name);
-    // TODO: should we use the IntToGdbHex funcs instead of fmt::format_to ?
+    // We need a null-terminated string from char* instead of using
+    // the full length of the array (like {.begin(), .end()} constructor would)
+    std::string_view function_name{current_hio_request.function_name.data()};
 
-    u32 nStr = 0;
+    std::string packet = fmt::format("F{}", function_name);
+
+    u32 str_length_idx = 0;
 
     for (u32 i = 0; i < 8 && current_hio_request.param_format[i] != 0; i++) {
         u64 param = current_hio_request.parameters[i];
 
+        // TODO: should we use the IntToGdbHex funcs instead of fmt::format_to ?
         switch (current_hio_request.param_format[i]) {
         case 'i':
         case 'I':
         case 'p':
-            // For pointers and 32-bit ints, truncate before sending
+            // For pointers and 32-bit ints, truncate down to size before sending
             param = static_cast<u32>(param);
+            [[fallthrough]];
 
         case 'l':
         case 'L':
@@ -230,7 +240,7 @@ bool HandlePendingHioRequestPacket() {
             // strings are written as {pointer}/{length}
             fmt::format_to(std::back_inserter(packet), ",{:x}/{:x}",
                            static_cast<u32>(current_hio_request.parameters[i]),
-                           current_hio_request.string_lengths[nStr++]);
+                           current_hio_request.string_lengths[str_length_idx++]);
             break;
 
         default:
@@ -241,7 +251,7 @@ bool HandlePendingHioRequestPacket() {
         }
     }
 
-    LOG_TRACE(Debug_GDBStub, "HIO request packet: {}", packet);
+    LOG_TRACE(Debug_GDBStub, "HIO request packet: '{}'", packet);
 
     SendReply(packet.data());
     request_status = Status::SentWaitingReply;

src/core/gdbstub/hio.h

@@ -14,19 +14,25 @@ namespace GDBStub {
  * A request from a debugged application to perform some I/O with the GDB client.
  * This structure is also used to encode the reply back to the application.
  *
- * Based on the Rosalina implementation:
+ * Based on the Rosalina + libctru implementations:
  * https://github.com/LumaTeam/Luma3DS/blob/master/sysmodules/rosalina/include/gdb.h#L46C27-L62
+ * https://github.com/devkitPro/libctru/blob/master/libctru/source/gdbhio.c#L71-L87
  */
 struct PackedGdbHioRequest {
-    char magic[4]; // "GDB\0"
+    std::array<char, 4> magic; // "GDB\0"
     u32 version;
 
-    // Request
-    char function_name[16 + 1];
-    char param_format[8 + 1];
+private:
+    static inline constexpr std::size_t MAX_FUNCNAME_LEN = 16;
+    static inline constexpr std::size_t PARAM_COUNT = 8;
 
-    u64 parameters[8];
-    u32 string_lengths[8];
+public:
+    // Request. Char arrays have +1 entry for null terminator
+    std::array<char, MAX_FUNCNAME_LEN + 1> function_name;
+    std::array<char, PARAM_COUNT + 1> param_format;
+
+    std::array<u64, PARAM_COUNT> parameters;
+    std::array<u32, PARAM_COUNT> string_lengths;
 
     // Return
     s64 retval;
@@ -34,6 +40,9 @@ struct PackedGdbHioRequest {
     bool ctrl_c;
 };
 
+static_assert(sizeof(PackedGdbHioRequest) == 152,
+              "HIO request size must match libctru implementation");
+
 /**
  * Set the current HIO request to the given address. This is how the debugged
  * app indicates to the gdbstub that it wishes to perform a request.