Merge pull request #6395 from ian-h-chamberlain/feature/gdbstub-hio

Initial port of luma3ds' gdb_hio to Citra
This commit is contained in:
SachinVin 2023-04-11 20:32:48 +05:30 committed by GitHub
commit 2a2ee8bc96
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GPG key ID: 4AEE18F83AFDEB23
6 changed files with 391 additions and 20 deletions

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@ -115,6 +115,8 @@ add_library(core STATIC
frontend/mic.h
gdbstub/gdbstub.cpp
gdbstub/gdbstub.h
gdbstub/hio.cpp
gdbstub/hio.h
hle/applets/applet.cpp
hle/applets/applet.h
hle/applets/erreula.cpp

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@ -35,6 +35,7 @@
#include "core/arm/arm_interface.h"
#include "core/core.h"
#include "core/gdbstub/gdbstub.h"
#include "core/gdbstub/hio.h"
#include "core/hle/kernel/process.h"
#include "core/loader/loader.h"
#include "core/memory.h"
@ -261,13 +262,7 @@ static u8 NibbleToHex(u8 n) {
}
}
/**
* Converts input hex string characters into an array of equivalent of u8 bytes.
*
* @param src Pointer to array of output hex string characters.
* @param len Length of src array.
*/
static u32 HexToInt(const u8* src, std::size_t len) {
u32 HexToInt(const u8* src, std::size_t len) {
u32 output = 0;
while (len-- > 0) {
output = (output << 4) | HexCharToValue(src[0]);
@ -492,12 +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;
}
@ -653,7 +643,7 @@ static void ReadCommand() {
memset(command_buffer, 0, sizeof(command_buffer));
u8 c = ReadByte();
if (c == '+') {
if (c == GDB_STUB_ACK) {
// ignore ack
return;
} else if (c == 0x03) {
@ -843,7 +833,7 @@ static void ReadMemory() {
u32 len =
HexToInt(start_offset, static_cast<u32>((command_buffer + command_length) - start_offset));
LOG_DEBUG(Debug_GDBStub, "gdb: addr: {:08x} len: {:08x}\n", addr, len);
LOG_DEBUG(Debug_GDBStub, "ReadMemory addr: {:08x} len: {:08x}", addr, len);
if (len * 2 > sizeof(reply)) {
SendReply("E01");
@ -860,7 +850,11 @@ static void ReadMemory() {
MemToGdbHex(reply, data.data(), len);
reply[len * 2] = '\0';
SendReply(reinterpret_cast<char*>(reply));
auto reply_str = reinterpret_cast<char*>(reply);
LOG_DEBUG(Debug_GDBStub, "ReadMemory result: {}", reply_str);
SendReply(reply_str);
}
/// Modify location in memory with data received from the gdb client.
@ -1050,6 +1044,11 @@ void HandlePacket() {
return;
}
if (HandlePendingHioRequestPacket()) {
// Don't do anything else while we wait for the client to respond
return;
}
if (!IsDataAvailable()) {
return;
}
@ -1059,7 +1058,7 @@ void HandlePacket() {
return;
}
LOG_DEBUG(Debug_GDBStub, "Packet: {}", command_buffer[0]);
LOG_DEBUG(Debug_GDBStub, "Packet: {0:d} ('{0:c}')", command_buffer[0]);
switch (command_buffer[0]) {
case 'q':
@ -1072,9 +1071,14 @@ void HandlePacket() {
SendSignal(current_thread, latest_signal);
break;
case 'k':
Shutdown();
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':
HandleHioReply(command_buffer, command_length);
break;
case 'g':
ReadRegisters();
break;
@ -1251,6 +1255,10 @@ bool GetCpuHaltFlag() {
return halt_loop;
}
void SetCpuHaltFlag(bool halt) {
halt_loop = halt;
}
bool GetCpuStepFlag() {
return step_loop;
}
@ -1265,6 +1273,7 @@ void SendTrap(Kernel::Thread* thread, int trap) {
}
current_thread = thread;
SendSignal(thread, trap);
halt_loop = true;

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@ -90,6 +90,13 @@ 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.
bool GetCpuStepFlag();
@ -107,4 +114,19 @@ void SetCpuStepFlag(bool is_step);
* @param trap Trap no.
*/
void SendTrap(Kernel::Thread* thread, int trap);
/**
* 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.
* @param len Length of src array.
*/
u32 HexToInt(const u8* src, std::size_t len);
} // namespace GDBStub

261
src/core/gdbstub/hio.cpp Normal file
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@ -0,0 +1,261 @@
// Copyright 2023 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <fmt/ranges.h>
#include "common/string_util.h"
#include "core/core.h"
#include "core/gdbstub/gdbstub.h"
#include "core/gdbstub/hio.h"
namespace GDBStub {
namespace {
static VAddr current_hio_request_addr;
static PackedGdbHioRequest current_hio_request;
enum class Status {
NoRequest,
NotSent,
SentWaitingReply,
};
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 IsWaitingForHioReply() {
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 (IsWaitingForHioReply()) {
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();
if (!memory.IsValidVirtualAddress(*process, addr)) {
LOG_WARNING(Debug_GDBStub, "Invalid address for HIO request");
return;
}
memory.ReadBlock(*process, addr, &current_hio_request, sizeof(PackedGdbHioRequest));
if (current_hio_request.magic != std::array{'G', 'D', 'B', '\0'}) {
std::string_view bad_magic{
current_hio_request.magic.data(),
current_hio_request.magic.size(),
};
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;
return;
}
LOG_DEBUG(Debug_GDBStub, "HIO request initiated at 0x{:X}", 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();
SetCpuHaltFlag(true);
SetCpuStepFlag(false);
Core::GetRunningCore().ClearInstructionCache();
}
void HandleHioReply(const u8* const command_buffer, const u32 command_length) {
if (!IsWaitingForHioReply()) {
LOG_WARNING(Debug_GDBStub, "Got HIO reply but never sent a request");
return;
}
// Skip 'F' header
auto* command_pos = command_buffer + 1;
if (*command_pos == 0 || *command_pos == ',') {
LOG_WARNING(Debug_GDBStub, "bad HIO packet format position 0: {}", *command_pos);
SendErrorReply(EILSEQ);
return;
}
// Set the sign of the retval
if (*command_pos == '-') {
command_pos++;
current_hio_request.retval = -1;
} else {
if (*command_pos == '+') {
command_pos++;
}
current_hio_request.retval = 1;
}
const std::string command_str{command_pos, command_buffer + command_length};
std::vector<std::string> command_parts;
Common::SplitString(command_str, ',', command_parts);
if (command_parts.empty() || command_parts.size() > 3) {
LOG_WARNING(Debug_GDBStub, "Unexpected reply packet size: {}", command_parts);
SendErrorReply(EILSEQ);
return;
}
u64 unsigned_retval =
HexToInt(reinterpret_cast<const u8*>(command_parts[0].data()), command_parts[0].size());
current_hio_request.retval *= unsigned_retval;
if (command_parts.size() > 1) {
// Technically the errno could be signed but in practice this doesn't happen
current_hio_request.gdb_errno =
HexToInt(reinterpret_cast<const u8*>(command_parts[1].data()), command_parts[1].size());
} else {
current_hio_request.gdb_errno = 0;
}
current_hio_request.ctrl_c = false;
if (command_parts.size() > 2 && !command_parts[2].empty()) {
if (command_parts[2][0] != 'C') {
LOG_WARNING(Debug_GDBStub, "expected ctrl-c flag got '{}'", command_parts[2][0]);
SendErrorReply(EILSEQ);
return;
}
// for now we just ignore any trailing ";..." attachments
current_hio_request.ctrl_c = true;
}
std::fill(std::begin(current_hio_request.param_format),
std::end(current_hio_request.param_format), 0);
LOG_TRACE(Debug_GDBStub, "HIO reply: {{retval = {}, errno = {}, ctrl_c = {}}}",
current_hio_request.retval, current_hio_request.gdb_errno,
current_hio_request.ctrl_c);
const auto process = Core::System::GetInstance().Kernel().GetCurrentProcess();
auto& memory = Core::System::GetInstance().Memory();
// should have been checked when we first initialized the request,
// but just double check again before we write to memory
if (!memory.IsValidVirtualAddress(*process, current_hio_request_addr)) {
LOG_WARNING(Debug_GDBStub, "Invalid address {:#X} to write HIO reply",
current_hio_request_addr);
return;
}
memory.WriteBlock(*process, current_hio_request_addr, &current_hio_request,
sizeof(PackedGdbHioRequest));
current_hio_request = {};
current_hio_request_addr = 0;
request_status = Status::NoRequest;
// Restore state from before the request came in
SetCpuStepFlag(was_stepping);
SetCpuHaltFlag(was_halted);
Core::GetRunningCore().ClearInstructionCache();
}
bool HandlePendingHioRequestPacket() {
if (!HasPendingHioRequest()) {
return false;
}
if (IsWaitingForHioReply()) {
// We already sent it, continue waiting for a reply
return true;
}
// 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()};
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 down to size before sending
param = static_cast<u32>(param);
[[fallthrough]];
case 'l':
case 'L':
fmt::format_to(std::back_inserter(packet), ",{:x}", param);
break;
case 's':
// 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[str_length_idx++]);
break;
default:
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);
SendReply(packet.data());
request_status = Status::SentWaitingReply;
return true;
}
} // namespace GDBStub

64
src/core/gdbstub/hio.h Normal file
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@ -0,0 +1,64 @@
// Copyright 2023 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#pragma once
#include "common/common_types.h"
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 + 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 {
std::array<char, 4> magic; // "GDB\0"
u32 version;
private:
static inline constexpr std::size_t MAX_FUNCNAME_LEN = 16;
static inline constexpr std::size_t PARAM_COUNT = 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;
s32 gdb_errno;
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.
*
* @param address The memory address of the \ref PackedGdbHioRequest.
*/
void SetHioRequest(const VAddr address);
/**
* If there is a pending HIO request, send it to the client.
*
* @returns whethere any request was sent to the client.
*/
bool HandlePendingHioRequestPacket();
/**
* Process an HIO reply from the client.
*/
void HandleHioReply(const u8* const command_buffer, const u32 command_length);
} // namespace GDBStub

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@ -13,6 +13,7 @@
#include "core/arm/arm_interface.h"
#include "core/core.h"
#include "core/core_timing.h"
#include "core/gdbstub/hio.h"
#include "core/hle/kernel/address_arbiter.h"
#include "core/hle/kernel/client_port.h"
#include "core/hle/kernel/client_session.h"
@ -1140,9 +1141,21 @@ void SVC::Break(u8 break_reason) {
system.SetStatus(Core::System::ResultStatus::ErrorUnknown);
}
/// Used to output a message on a debug hardware unit - 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 (len <= 0) {
if (!memory.IsValidVirtualAddress(*kernel.GetCurrentProcess(), address)) {
LOG_WARNING(Kernel_SVC, "OutputDebugString called with invalid address {:X}", address);
return;
}
if (len == 0) {
GDBStub::SetHioRequest(address);
return;
}
if (len < 0) {
LOG_WARNING(Kernel_SVC, "OutputDebugString called with invalid length {}", len);
return;
}