Atmosphere/stratosphere/fatal/source/fatal_debug.cpp
2020-01-17 20:11:03 -08:00

293 lines
11 KiB
C++

/*
* Copyright (c) 2018-2019 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 "fatal_debug.hpp"
#include "fatal_config.hpp"
namespace ams::fatal::srv {
namespace {
constexpr u32 SvcSendSyncRequestInstruction = 0xD4000421;
struct StackFrame {
u64 fp;
u64 lr;
};
bool IsThreadFatalCaller(Result result, u32 debug_handle, u64 thread_id, u64 thread_tls_addr, ThreadContext *thread_ctx) {
/* Verify that the thread is running or waiting. */
{
u64 _;
u32 _thread_state;
if (R_FAILED(svcGetDebugThreadParam(&_, &_thread_state, debug_handle, thread_id, DebugThreadParam_State))) {
return false;
}
const svc::ThreadState 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(svcGetDebugThreadContext(thread_ctx, debug_handle, thread_id, svc::ThreadContextFlag_All))) {
return false;
}
/* Try to read the current instruction. */
u32 insn;
if (R_FAILED(svcReadDebugProcessMemory(&insn, debug_handle, thread_ctx->pc.x, sizeof(insn)))) {
return false;
}
/* If the instruction isn't svcSendSyncRequest, it's not the fatal caller. */
if (insn != SvcSendSyncRequestInstruction) {
return false;
}
/* Read in the fatal caller's TLS. */
u8 thread_tls[0x100];
if (R_FAILED(svcReadDebugProcessMemory(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;
}
default:
return false;
}
if (in_data->result.GetValue() != result.GetValue()) {
return false;
}
}
/* We found our caller. */
return true;
}
bool TryGuessBaseAddress(u64 *out_base_address, u32 debug_handle, u64 guess) {
MemoryInfo mi;
u32 pi;
if (R_FAILED(svcQueryDebugProcessMemory(&mi, &pi, debug_handle, guess)) || mi.perm != Perm_Rx) {
return false;
}
/* Iterate backwards until we find the memory before the code region. */
while (mi.addr > 0) {
if (R_FAILED(svcQueryDebugProcessMemory(&mi, &pi, debug_handle, guess))) {
return false;
}
if (mi.type == MemType_Unmapped) {
/* Code region will be at the end of the unmapped region preceding it. */
*out_base_address = mi.addr + mi.size;
return true;
}
guess = mi.addr - 4;
}
return false;
}
u64 GetBaseAddress(const ThrowContext *throw_ctx, const ThreadContext *thread_ctx, u32 debug_handle) {
u64 base_address = 0;
if (TryGuessBaseAddress(&base_address, debug_handle, thread_ctx->pc.x)) {
return base_address;
}
if (TryGuessBaseAddress(&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(&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::ManagedHandle debug_handle;
if (R_FAILED(svcDebugActiveProcess(debug_handle.GetPointer(), static_cast<u64>(process_id)))) {
return;
}
/* First things first, check if process is 64 bits, and get list of thread infos. */
std::unordered_map<u64, u64> thread_id_to_tls;
{
bool got_attach_process = false;
svc::DebugEventInfo d;
while (R_SUCCEEDED(svcGetDebugEvent(reinterpret_cast<u8 *>(&d), debug_handle.Get()))) {
switch (d.type) {
case svc::DebugEvent_AttachProcess:
ctx->cpu_ctx.architecture = (d.info.attach_process.flags & 1) ? CpuContext::Architecture_Aarch64 : CpuContext::Architecture_Aarch32;
std::memcpy(ctx->proc_name, d.info.attach_process.name, sizeof(d.info.attach_process.name));
got_attach_process = true;
break;
case svc::DebugEvent_AttachThread:
thread_id_to_tls[d.info.attach_thread.thread_id] = d.info.attach_thread.tls_address;
break;
case svc::DebugEvent_Exception:
case svc::DebugEvent_ExitProcess:
case svc::DebugEvent_ExitThread:
break;
}
}
if (!got_attach_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;
ThreadContext thread_ctx;
{
/* We start by trying to get a list of threads. */
u32 thread_count;
u64 thread_ids[0x60];
if (R_FAILED(svcGetThreadList(&thread_count, thread_ids, 0x60, debug_handle.Get()))) {
return;
}
/* We need to locate the thread that's called fatal. */
for (u32 i = 0; i < thread_count; i++) {
const u64 cur_thread_id = thread_ids[i];
if (thread_id_to_tls.find(cur_thread_id) == thread_id_to_tls.end()) {
continue;
}
if (IsThreadFatalCaller(ctx->result, debug_handle.Get(), cur_thread_id, thread_id_to_tls[cur_thread_id], &thread_ctx)) {
thread_id = cur_thread_id;
thread_tls = thread_id_to_tls[thread_id];
found_fatal_caller = true;
break;
}
}
if (!found_fatal_caller) {
return;
}
}
if (R_FAILED(svcGetDebugThreadContext(&thread_ctx, debug_handle.Get(), 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.x);
/* 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(svcReadDebugProcessMemory(&cur_frame, debug_handle.Get(), 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(svcReadDebugProcessMemory(ctx->stack_dump, debug_handle.Get(), 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(svcReadDebugProcessMemory(ctx->tls_dump, debug_handle.Get(), 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, &thread_ctx, debug_handle.Get()));
}
}