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Atmosphere/stratosphere/fatal/source/fatal_debug.cpp

331 lines
13 KiB
C++

/*
* Copyright (c) Atmosphère-NX
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stratosphere.hpp>
#include "fatal_debug.hpp"
#include "fatal_config.hpp"
namespace ams::fatal::srv {
namespace {
constexpr u32 SvcSendSyncRequestInstruction = 0xD4000421;
struct StackFrame {
u64 fp;
u64 lr;
};
constexpr inline size_t MaxThreads = 0x60;
template<size_t MaxThreadCount>
class ThreadTlsMapImpl {
private:
std::pair<u64, u64> m_map[MaxThreadCount];
size_t m_index;
public:
constexpr ThreadTlsMapImpl() : m_map(), m_index(0) { /* ... */ }
constexpr void ResetThreadTlsMap() {
m_index = 0;
}
constexpr void SetThreadTls(u64 thread_id, u64 tls) {
if (m_index < util::size(m_map)) {
m_map[m_index++] = std::make_pair(thread_id, tls);
}
}
constexpr bool GetThreadTls(u64 *out, u64 thread_id) const {
for (size_t i = 0; i < m_index; ++i) {
if (m_map[i].first == thread_id) {
*out = m_map[i].second;
return true;
}
}
return false;
}
};
using ThreadTlsMap = ThreadTlsMapImpl<MaxThreads>;
constinit ThreadTlsMap g_thread_id_to_tls_map;
bool IsThreadFatalCaller(Result result, os::NativeHandle debug_handle, u64 thread_id, u64 thread_tls_addr, svc::ThreadContext *thread_ctx) {
/* Verify that the thread is running or waiting. */
{
u64 _;
u32 _thread_state;
if (R_FAILED(svc::GetDebugThreadParam(&_, &_thread_state, debug_handle, thread_id, svc::DebugThreadParam_State))) {
return false;
}
const auto thread_state = static_cast<svc::ThreadState>(_thread_state);
if (thread_state != svc::ThreadState_Waiting && thread_state != svc::ThreadState_Running) {
return false;
}
}
/* Get the thread context. */
if (R_FAILED(svc::GetDebugThreadContext(thread_ctx, debug_handle, thread_id, svc::ThreadContextFlag_All))) {
return false;
}
/* Try to read the current instruction. */
u32 insn;
if (R_FAILED(svc::ReadDebugProcessMemory(reinterpret_cast<uintptr_t>(std::addressof(insn)), debug_handle, thread_ctx->pc, sizeof(insn)))) {
return false;
}
/* If the instruction isn't svc::SendSyncRequest, it's not the fatal caller. */
if (insn != SvcSendSyncRequestInstruction) {
return false;
}
/* Read in the fatal caller's TLS. */
u8 thread_tls[sizeof(svc::ThreadLocalRegion::message_buffer)];
if (R_FAILED(svc::ReadDebugProcessMemory(reinterpret_cast<uintptr_t>(thread_tls), debug_handle, thread_tls_addr, sizeof(thread_tls)))) {
return false;
}
/* We want to parse the command the fatal caller sent. */
{
const auto request = hipcParseRequest(thread_tls);
const struct {
CmifInHeader header;
Result result;
} *in_data = decltype(in_data)(request.data.data_words);
static_assert(sizeof(*in_data) == 0x14, "InData!");
/* Fatal command takes in a PID, only one buffer max. */
if ((request.meta.type != CmifCommandType_Request && request.meta.type != CmifCommandType_RequestWithContext) ||
!request.meta.send_pid ||
request.meta.num_send_statics ||
request.meta.num_recv_statics ||
request.meta.num_recv_buffers ||
request.meta.num_exch_buffers ||
request.meta.num_copy_handles ||
request.meta.num_move_handles ||
request.meta.num_data_words < ((sizeof(*in_data) + 0x10) / sizeof(u32)))
{
return false;
}
if (in_data->header.magic != CMIF_IN_HEADER_MAGIC) {
return false;
}
if (in_data->header.version > 1) {
return false;
}
switch (in_data->header.command_id) {
case 0:
case 1:
if (request.meta.num_send_buffers != 0) {
return false;
}
break;
case 2:
if (request.meta.num_send_buffers != 1) {
return false;
}
break;
default:
return false;
}
if (in_data->result.GetValue() != result.GetValue()) {
return false;
}
}
/* We found our caller. */
return true;
}
bool TryGuessBaseAddress(u64 *out_base_address, os::NativeHandle debug_handle, u64 guess) {
svc::MemoryInfo mi;
svc::PageInfo pi;
if (R_FAILED(svc::QueryDebugProcessMemory(std::addressof(mi), std::addressof(pi), debug_handle, guess)) || mi.permission != svc::MemoryPermission_ReadExecute) {
return false;
}
/* Iterate backwards until we find the memory before the code region. */
while (mi.base_address > 0) {
if (R_FAILED(svc::QueryDebugProcessMemory(std::addressof(mi), std::addressof(pi), debug_handle, guess))) {
return false;
}
if (mi.state == svc::MemoryState_Free) {
/* Code region will be at the end of the unmapped region preceding it. */
*out_base_address = mi.base_address + mi.size;
return true;
}
guess = mi.base_address - 4;
}
return false;
}
u64 GetBaseAddress(const ThrowContext *throw_ctx, const svc::ThreadContext *thread_ctx, os::NativeHandle debug_handle) {
u64 base_address = 0;
if (TryGuessBaseAddress(std::addressof(base_address), debug_handle, thread_ctx->pc)) {
return base_address;
}
if (TryGuessBaseAddress(std::addressof(base_address), debug_handle, thread_ctx->lr)) {
return base_address;
}
for (size_t i = 0; i < throw_ctx->cpu_ctx.aarch64_ctx.stack_trace_size; i++) {
if (TryGuessBaseAddress(std::addressof(base_address), debug_handle, throw_ctx->cpu_ctx.aarch64_ctx.stack_trace[i])) {
return base_address;
}
}
return base_address;
}
}
void TryCollectDebugInformation(ThrowContext *ctx, os::ProcessId process_id) {
/* Try to debug the process. This may fail, if we called into ourself. */
os::NativeHandle debug_handle;
if (R_FAILED(svc::DebugActiveProcess(std::addressof(debug_handle), process_id.value))) {
return;
}
ON_SCOPE_EXIT { os::CloseNativeHandle(debug_handle); };
/* First things first, check if process is 64 bits, and get list of thread infos. */
g_thread_id_to_tls_map.ResetThreadTlsMap();
{
bool got_create_process = false;
svc::DebugEventInfo d;
while (R_SUCCEEDED(svc::GetDebugEvent(std::addressof(d), debug_handle))) {
switch (d.type) {
case svc::DebugEvent_CreateProcess:
ctx->cpu_ctx.architecture = (d.info.create_process.flags & 1) ? CpuContext::Architecture_Aarch64 : CpuContext::Architecture_Aarch32;
std::memcpy(ctx->proc_name, d.info.create_process.name, sizeof(d.info.create_process.name));
got_create_process = true;
break;
case svc::DebugEvent_CreateThread:
g_thread_id_to_tls_map.SetThreadTls(d.info.create_thread.thread_id, d.info.create_thread.tls_address);
break;
case svc::DebugEvent_Exception:
case svc::DebugEvent_ExitProcess:
case svc::DebugEvent_ExitThread:
break;
}
}
if (!got_create_process) {
return;
}
}
/* TODO: Try to collect information on 32-bit fatals. This shouldn't really matter for any real use case. */
if (ctx->cpu_ctx.architecture == CpuContext::Architecture_Aarch32) {
return;
}
/* Welcome to hell. Here, we try to identify which thread called into fatal. */
bool found_fatal_caller = false;
u64 thread_id = 0;
u64 thread_tls = 0;
svc::ThreadContext thread_ctx;
{
/* We start by trying to get a list of threads. */
s32 thread_count;
u64 thread_ids[0x60];
if (R_FAILED(svc::GetThreadList(std::addressof(thread_count), thread_ids, 0x60, debug_handle))) {
return;
}
/* We need to locate the thread that's called fatal. */
for (s32 i = 0; i < thread_count; i++) {
const u64 cur_thread_id = thread_ids[i];
u64 cur_thread_tls;
if (!g_thread_id_to_tls_map.GetThreadTls(std::addressof(cur_thread_tls), cur_thread_id)) {
continue;
}
if (IsThreadFatalCaller(ctx->result, debug_handle, cur_thread_id, cur_thread_tls, std::addressof(thread_ctx))) {
thread_id = cur_thread_id;
thread_tls = cur_thread_tls;
found_fatal_caller = true;
break;
}
}
if (!found_fatal_caller) {
return;
}
}
if (R_FAILED(svc::GetDebugThreadContext(std::addressof(thread_ctx), debug_handle, thread_id, svc::ThreadContextFlag_All))) {
return;
}
/* Set register states. */
ctx->cpu_ctx.aarch64_ctx.SetRegisterValue(aarch64::RegisterName_FP, thread_ctx.fp);
ctx->cpu_ctx.aarch64_ctx.SetRegisterValue(aarch64::RegisterName_LR, thread_ctx.lr);
ctx->cpu_ctx.aarch64_ctx.SetRegisterValue(aarch64::RegisterName_SP, thread_ctx.sp);
ctx->cpu_ctx.aarch64_ctx.SetRegisterValue(aarch64::RegisterName_PC, thread_ctx.pc);
/* Parse a stack trace. */
u64 cur_fp = thread_ctx.fp;
ctx->cpu_ctx.aarch64_ctx.stack_trace_size = 0;
for (unsigned int i = 0; i < aarch64::CpuContext::MaxStackTraceDepth; i++) {
/* Validate the current frame. */
if (cur_fp == 0 || (cur_fp & 0xF)) {
break;
}
/* Read a new frame. */
StackFrame cur_frame = {};
if (R_FAILED(svc::ReadDebugProcessMemory(reinterpret_cast<uintptr_t>(std::addressof(cur_frame)), debug_handle, cur_fp, sizeof(StackFrame)))) {
break;
}
/* Advance to the next frame. */
ctx->cpu_ctx.aarch64_ctx.stack_trace[ctx->cpu_ctx.aarch64_ctx.stack_trace_size++] = cur_frame.lr;
cur_fp = cur_frame.fp;
}
/* Try to read up to 0x100 of stack. */
ctx->stack_dump_base = 0;
for (size_t sz = 0x100; sz > 0; sz -= 0x10) {
if (R_SUCCEEDED(svc::ReadDebugProcessMemory(reinterpret_cast<uintptr_t>(ctx->stack_dump), debug_handle, thread_ctx.sp, sz))) {
ctx->stack_dump_base = thread_ctx.sp;
ctx->stack_dump_size = sz;
break;
}
}
/* Try to read the first 0x100 of TLS. */
if (R_SUCCEEDED(svc::ReadDebugProcessMemory(reinterpret_cast<uintptr_t>(ctx->tls_dump), debug_handle, thread_tls, sizeof(ctx->tls_dump)))) {
ctx->tls_address = thread_tls;
} else {
ctx->tls_address = 0;
std::memset(ctx->tls_dump, 0xCC, sizeof(ctx->tls_dump));
}
/* Parse the base address. */
ctx->cpu_ctx.aarch64_ctx.SetBaseAddress(GetBaseAddress(ctx, std::addressof(thread_ctx), debug_handle));
}
}