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Cleanup new code, add docs and error handling

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This commit is contained in:
Ian Chamberlain 2023-04-04 13:09:34 -04:00
parent 0d4c93d1c2
commit 6e45de760e
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GPG key ID: AE5484D09405AA60
5 changed files with 112 additions and 59 deletions
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28
src/core/gdbstub/gdbstub.cpp
View file

@ -487,12 +487,7 @@ static void SendPacket(const char packet) {
}
}
/**
* Send reply to gdb client.
*
* @param reply Reply to be sent to client.
*/
static void SendReply(const char* reply) {
void SendReply(const char* reply) {
if (!IsConnected()) {
return;
}
@ -1048,9 +1043,8 @@ void HandlePacket() {
return;
}
if (HasPendingHioRequest()) {
const auto request_packet = BuildHioRequestPacket();
SendReply(request_packet.data());
if (HandlePendingHioRequestPacket()) {
// Don't do anything else while we wait for the client to respond
return;
}
@ -1076,21 +1070,13 @@ void HandlePacket() {
SendSignal(current_thread, latest_signal);
break;
case 'k':
ToggleServer(false);
// Continue execution so we don't hang forever after shutting down the
// server
Continue();
LOG_INFO(Debug_GDBStub, "killed by gdb");
ToggleServer(false);
// Continue execution so we don't hang forever after shutting down the server
Continue();
return;
case 'F':
if (HandleHioReply(command_buffer, command_length)) {
// TODO: technically if we were paused when the request came in, we
// shouldn't continue here. Could recurse back into HandlePacket() maybe??
Continue();
} else {
// TODO reply with errno if relevant. Maybe that code should live in
// HandleHioReply
}
HandleHioReply(command_buffer, command_length);
break;
case 'g':
ReadRegisters();

13
src/core/gdbstub/gdbstub.h
View file

@ -90,6 +90,11 @@ bool CheckBreakpoint(VAddr addr, GDBStub::BreakpointType type);
// If set to true, the CPU will halt at the beginning of the next CPU loop.
bool GetCpuHaltFlag();
/**
* If set to true, the CPU will halt at the beginning of the next CPU loop.
*
* @param halt whether to halt on the next loop
*/
void SetCpuHaltFlag(bool halt);
// If set to true and the CPU is halted, the CPU will step one instruction.
@ -111,7 +116,13 @@ void SetCpuStepFlag(bool is_step);
void SendTrap(Kernel::Thread* thread, int trap);
/**
u32 HexToInt(const u8* src, std::size_t len) {
* Send reply to gdb client.
*
* @param reply Reply to be sent to client.
*/
void SendReply(const char* reply);
/**
* Converts input hex string characters into an array of equivalent of u8 bytes.
*
* @param src Pointer to array of output hex string characters.

92
src/core/gdbstub/hio.cpp
View file

@ -1,4 +1,4 @@
// Copyright 2022 Citra Emulator Project
// Copyright 2023 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
@ -23,19 +23,52 @@ enum class Status {
static std::atomic<Status> request_status{Status::NoRequest};
static std::atomic<bool> was_halted = false;
static std::atomic<bool> was_stepping = false;
} // namespace
/**
* @return Whether the application has requested I/O, and it has not been sent.
*/
static bool HasPendingHioRequest() {
return current_hio_request_addr != 0 && request_status == Status::NotSent;
}
/**
* @return Whether the GDB stub is awaiting a reply from the client.
*/
static bool WaitingForHioReply() {
return current_hio_request_addr != 0 && request_status == Status::SentWaitingReply;
}
/**
* Send a response indicating an error back to the application.
*
* @param error_code The error code to respond back to the app. This typically corresponds to errno.
*
* @param retval The return value of the syscall the app requested.
*/
static void SendErrorReply(int error_code, int retval = -1) {
auto packet = fmt::format("F{:x},{:x}", retval, error_code);
SendReply(packet.data());
}
void SetHioRequest(const VAddr addr) {
if (!IsServerEnabled()) {
LOG_WARNING(Debug_GDBStub, "HIO requested but GDB stub is not running");
return;
}
if (HasPendingHioRequest() || WaitingForHioReply()) {
if (WaitingForHioReply()) {
LOG_WARNING(Debug_GDBStub, "HIO requested while already in progress!");
return;
}
if (HasPendingHioRequest()) {
LOG_INFO(Debug_GDBStub, "overwriting existing HIO request that was not sent yet");
}
auto& memory = Core::System::GetInstance().Memory();
const auto process = Core::System::GetInstance().Kernel().GetCurrentProcess();
@ -59,6 +92,9 @@ void SetHioRequest(const VAddr addr) {
current_hio_request_addr = addr;
request_status = Status::NotSent;
was_halted = GetCpuHaltFlag();
was_stepping = GetCpuStepFlag();
// Now halt, so that no further instructions are executed until the request
// is processed by the client. We will continue after the reply comes back
Break();
@ -67,19 +103,19 @@ void SetHioRequest(const VAddr addr) {
Core::GetRunningCore().ClearInstructionCache();
}
bool HandleHioReply(const u8* const command_buffer, const u32 command_length) {
void HandleHioReply(const u8* const command_buffer, const u32 command_length) {
if (!WaitingForHioReply()) {
LOG_WARNING(Debug_GDBStub, "Got HIO reply but never sent a request");
// TODO send error reply packet?
return false;
return;
}
// Skip 'F' header
auto* command_pos = command_buffer + 1;
if (*command_pos == 0 || *command_pos == ',') {
// return GDB_ReplyErrno(ctx, EILSEQ);
return false;
LOG_WARNING(Debug_GDBStub, "bad HIO packet format position 0: {}", *command_pos);
SendErrorReply(EILSEQ);
return;
}
// Set the sign of the retval
@ -100,8 +136,8 @@ bool HandleHioReply(const u8* const command_buffer, const u32 command_length) {
if (command_parts.empty() || command_parts.size() > 3) {
LOG_WARNING(Debug_GDBStub, "unexpected reply packet size: {}", command_parts);
// return GDB_ReplyErrno(ctx, EILSEQ);
return false;
SendErrorReply(EILSEQ);
return;
}
u64 unsigned_retval = HexToInt((u8*)command_parts[0].data(), command_parts[0].size());
@ -119,8 +155,9 @@ bool HandleHioReply(const u8* const command_buffer, const u32 command_length) {
if (command_parts.size() > 2 && !command_parts[2].empty()) {
if (command_parts[2][0] != 'C') {
return false;
// return GDB_ReplyErrno(ctx, EILSEQ);
LOG_WARNING(Debug_GDBStub, "expected ctrl-c flag got '{}'", command_parts[2][0]);
SendErrorReply(EILSEQ);
return;
}
// for now we just ignore any trailing ";..." attachments
@ -142,7 +179,7 @@ bool HandleHioReply(const u8* const command_buffer, const u32 command_length) {
if (!memory.IsValidVirtualAddress(*process, current_hio_request_addr)) {
LOG_WARNING(Debug_GDBStub, "Invalid address {:#X} to write HIO reply",
current_hio_request_addr);
return false;
return;
}
memory.WriteBlock(*process, current_hio_request_addr, &current_hio_request,
@ -152,18 +189,22 @@ bool HandleHioReply(const u8* const command_buffer, const u32 command_length) {
current_hio_request_addr = 0;
request_status = Status::NoRequest;
return true;
// Restore state from before the request came in
SetCpuStepFlag(was_stepping);
SetCpuHaltFlag(was_halted);
Core::GetRunningCore().ClearInstructionCache();
}
bool HasPendingHioRequest() {
return current_hio_request_addr != 0 && request_status == Status::NotSent;
}
bool HandlePendingHioRequestPacket() {
if (!HasPendingHioRequest()) {
return false;
}
bool WaitingForHioReply() {
return current_hio_request_addr != 0 && request_status == Status::SentWaitingReply;
}
if (WaitingForHioReply()) {
// We already sent it, continue waiting for a reply
return true;
}
std::string BuildHioRequestPacket() {
std::string packet = fmt::format("F{}", current_hio_request.function_name);
// TODO: should we use the IntToGdbHex funcs instead of fmt::format_to ?
@ -192,17 +233,18 @@ std::string BuildHioRequestPacket() {
break;
default:
// TODO: early return? Or break out of this loop?
break;
LOG_WARNING(Debug_GDBStub, "unexpected hio request param format '{}'",
current_hio_request.param_format[i]);
SendErrorReply(EILSEQ);
return false;
}
}
LOG_TRACE(Debug_GDBStub, "HIO request packet: {}", packet);
// technically we should set this _after_ the reply is sent...
SendReply(packet.data());
request_status = Status::SentWaitingReply;
return packet;
return true;
}
} // namespace GDBStub

29
src/core/gdbstub/hio.h
View file

@ -1,4 +1,4 @@
// Copyright 2022 Citra Emulator Project
// Copyright 2023 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
@ -11,11 +11,14 @@
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:
* https://github.com/LumaTeam/Luma3DS/blob/master/sysmodules/rosalina/include/gdb.h#L46C27-L62
*/
struct PackedGdbHioRequest {
char magic[4]; // "GDB\x00"
char magic[4]; // "GDB\0"
u32 version;
// Request
@ -31,14 +34,24 @@ struct PackedGdbHioRequest {
bool ctrl_c;
};
/**
* 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.
*
* @param address The memory address of the \ref PackedGdbHioRequest.
*/
void SetHioRequest(const VAddr address);
bool HandleHioReply(const u8* const command_buffer, const u32 command_length);
/**
* If there is a pending HIO request, send it to the client.
*
* @returns whethere any request was sent to the client.
*/
bool HandlePendingHioRequestPacket();
bool HasPendingHioRequest();
bool WaitingForHioReply();
std::string BuildHioRequestPacket();
/**
* Process an HIO reply from the client.
*/
void HandleHioReply(const u8* const command_buffer, const u32 command_length);
} // namespace GDBStub

9
src/core/hle/kernel/svc.cpp
View file

@ -1141,8 +1141,8 @@ void SVC::Break(u8 break_reason) {
system.SetStatus(Core::System::ResultStatus::ErrorUnknown);
}
/// Used to output a message on a debug hardware unit, or for the GDB HIO
// protocol - does nothing on a retail unit.
/// Used to output a message on a debug hardware unit, or for the GDB file I/O
/// (HIO) protocol - does nothing on a retail unit.
void SVC::OutputDebugString(VAddr address, s32 len) {
if (!memory.IsValidVirtualAddress(*kernel.GetCurrentProcess(), address)) {
LOG_WARNING(Kernel_SVC, "OutputDebugString called with invalid address {:X}", address);
@ -1154,7 +1154,8 @@ void SVC::OutputDebugString(VAddr address, s32 len) {
return;
}
if (len <= 0) {
if (len < 0) {
LOG_WARNING(Kernel_SVC, "OutputDebugString called with invalid length {}", len);
return;
}
@ -2224,7 +2225,7 @@ const std::array<SVC::FunctionDef, 180> SVC::SVC_Table{{
{0x60, nullptr, "DebugActiveProcess"},
{0x61, nullptr, "BreakDebugProcess"},
{0x62, nullptr, "TerminateDebugProcess"},
{0x63, nullptr, "GetProcessDebugEvent"}, // TODO: do we need this for HIO to work?
{0x63, nullptr, "GetProcessDebugEvent"},
{0x64, nullptr, "ContinueDebugEvent"},
{0x65, &SVC::Wrap<&SVC::GetProcessList>, "GetProcessList"},
{0x66, nullptr, "GetThreadList"},