AppleGetItemInfoHandler.cpp
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//===-- AppleGetItemInfoHandler.cpp -------------------------------*- C++
//-*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "AppleGetItemInfoHandler.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/Value.h"
#include "lldb/Expression/DiagnosticManager.h"
#include "lldb/Expression/FunctionCaller.h"
#include "lldb/Expression/UtilityFunction.h"
#include "lldb/Symbol/ClangASTContext.h"
#include "lldb/Symbol/Symbol.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"
#include "lldb/Utility/ConstString.h"
#include "lldb/Utility/Log.h"
#include "lldb/Utility/StreamString.h"
using namespace lldb;
using namespace lldb_private;
const char *AppleGetItemInfoHandler::g_get_item_info_function_name =
"__lldb_backtrace_recording_get_item_info";
const char *AppleGetItemInfoHandler::g_get_item_info_function_code =
" \n\
extern \"C\" \n\
{ \n\
/* \n\
* mach defines \n\
*/ \n\
\n\
typedef unsigned int uint32_t; \n\
typedef unsigned long long uint64_t; \n\
typedef uint32_t mach_port_t; \n\
typedef mach_port_t vm_map_t; \n\
typedef int kern_return_t; \n\
typedef uint64_t mach_vm_address_t; \n\
typedef uint64_t mach_vm_size_t; \n\
\n\
mach_port_t mach_task_self (); \n\
kern_return_t mach_vm_deallocate (vm_map_t target, mach_vm_address_t address, mach_vm_size_t size); \n\
\n\
/* \n\
* libBacktraceRecording defines \n\
*/ \n\
\n\
typedef uint32_t queue_list_scope_t; \n\
typedef void *dispatch_queue_t; \n\
typedef void *introspection_dispatch_queue_info_t; \n\
typedef void *introspection_dispatch_item_info_ref; \n\
\n\
extern uint64_t __introspection_dispatch_queue_item_get_info (introspection_dispatch_item_info_ref item_info_ref, \n\
introspection_dispatch_item_info_ref *returned_queues_buffer, \n\
uint64_t *returned_queues_buffer_size); \n\
extern int printf(const char *format, ...); \n\
\n\
/* \n\
* return type define \n\
*/ \n\
\n\
struct get_item_info_return_values \n\
{ \n\
uint64_t item_info_buffer_ptr; /* the address of the items buffer from libBacktraceRecording */ \n\
uint64_t item_info_buffer_size; /* the size of the items buffer from libBacktraceRecording */ \n\
}; \n\
\n\
void __lldb_backtrace_recording_get_item_info \n\
(struct get_item_info_return_values *return_buffer, \n\
int debug, \n\
uint64_t /* introspection_dispatch_item_info_ref item_info_ref */ item, \n\
void *page_to_free, \n\
uint64_t page_to_free_size) \n\
{ \n\
if (debug) \n\
printf (\"entering get_item_info with args return_buffer == %p, debug == %d, item == 0x%llx, page_to_free == %p, page_to_free_size == 0x%llx\\n\", return_buffer, debug, item, page_to_free, page_to_free_size); \n\
if (page_to_free != 0) \n\
{ \n\
mach_vm_deallocate (mach_task_self(), (mach_vm_address_t) page_to_free, (mach_vm_size_t) page_to_free_size); \n\
} \n\
\n\
__introspection_dispatch_queue_item_get_info ((void*) item, \n\
(void**)&return_buffer->item_info_buffer_ptr, \n\
&return_buffer->item_info_buffer_size); \n\
} \n\
} \n\
";
AppleGetItemInfoHandler::AppleGetItemInfoHandler(Process *process)
: m_process(process), m_get_item_info_impl_code(),
m_get_item_info_function_mutex(),
m_get_item_info_return_buffer_addr(LLDB_INVALID_ADDRESS),
m_get_item_info_retbuffer_mutex() {}
AppleGetItemInfoHandler::~AppleGetItemInfoHandler() {}
void AppleGetItemInfoHandler::Detach() {
if (m_process && m_process->IsAlive() &&
m_get_item_info_return_buffer_addr != LLDB_INVALID_ADDRESS) {
std::unique_lock<std::mutex> lock(m_get_item_info_retbuffer_mutex,
std::defer_lock);
lock.try_lock(); // Even if we don't get the lock, deallocate the buffer
m_process->DeallocateMemory(m_get_item_info_return_buffer_addr);
}
}
// Compile our __lldb_backtrace_recording_get_item_info() function (from the
// source above in g_get_item_info_function_code) if we don't find that
// function in the inferior already with USE_BUILTIN_FUNCTION defined. (e.g.
// this would be the case for testing.)
//
// Insert the __lldb_backtrace_recording_get_item_info into the inferior
// process if needed.
//
// Write the get_item_info_arglist into the inferior's memory space to prepare
// for the call.
//
// Returns the address of the arguments written down in the inferior process,
// which can be used to make the function call.
lldb::addr_t AppleGetItemInfoHandler::SetupGetItemInfoFunction(
Thread &thread, ValueList &get_item_info_arglist) {
ExecutionContext exe_ctx(thread.shared_from_this());
DiagnosticManager diagnostics;
Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME));
lldb::addr_t args_addr = LLDB_INVALID_ADDRESS;
FunctionCaller *get_item_info_caller = nullptr;
// Scope for mutex locker:
{
std::lock_guard<std::mutex> guard(m_get_item_info_function_mutex);
// First stage is to make the UtilityFunction to hold our injected
// function:
if (!m_get_item_info_impl_code) {
if (g_get_item_info_function_code != nullptr) {
Status error;
m_get_item_info_impl_code.reset(
exe_ctx.GetTargetRef().GetUtilityFunctionForLanguage(
g_get_item_info_function_code, eLanguageTypeObjC,
g_get_item_info_function_name, error));
if (error.Fail()) {
LLDB_LOGF(log, "Failed to get utility function: %s.",
error.AsCString());
return args_addr;
}
if (!m_get_item_info_impl_code->Install(diagnostics, exe_ctx)) {
if (log) {
LLDB_LOGF(log, "Failed to install get-item-info introspection.");
diagnostics.Dump(log);
}
m_get_item_info_impl_code.reset();
return args_addr;
}
} else {
LLDB_LOGF(log, "No get-item-info introspection code found.");
return LLDB_INVALID_ADDRESS;
}
// Next make the runner function for our implementation utility function.
auto type_system_or_err =
thread.GetProcess()->GetTarget().GetScratchTypeSystemForLanguage(
eLanguageTypeC);
if (auto err = type_system_or_err.takeError()) {
LLDB_LOG_ERROR(log, std::move(err),
"Error inseting get-item-info function");
return args_addr;
}
CompilerType get_item_info_return_type =
type_system_or_err->GetBasicTypeFromAST(eBasicTypeVoid)
.GetPointerType();
Status error;
get_item_info_caller = m_get_item_info_impl_code->MakeFunctionCaller(
get_item_info_return_type, get_item_info_arglist,
thread.shared_from_this(), error);
if (error.Fail() || get_item_info_caller == nullptr) {
LLDB_LOGF(log, "Error Inserting get-item-info function: \"%s\".",
error.AsCString());
return args_addr;
}
} else {
// If it's already made, then we can just retrieve the caller:
get_item_info_caller = m_get_item_info_impl_code->GetFunctionCaller();
if (!get_item_info_caller) {
LLDB_LOGF(log, "Failed to get get-item-info introspection caller.");
m_get_item_info_impl_code.reset();
return args_addr;
}
}
}
diagnostics.Clear();
// Now write down the argument values for this particular call. This looks
// like it might be a race condition if other threads were calling into here,
// but actually it isn't because we allocate a new args structure for this
// call by passing args_addr = LLDB_INVALID_ADDRESS...
if (!get_item_info_caller->WriteFunctionArguments(
exe_ctx, args_addr, get_item_info_arglist, diagnostics)) {
if (log) {
LLDB_LOGF(log, "Error writing get-item-info function arguments.");
diagnostics.Dump(log);
}
return args_addr;
}
return args_addr;
}
AppleGetItemInfoHandler::GetItemInfoReturnInfo
AppleGetItemInfoHandler::GetItemInfo(Thread &thread, uint64_t item,
addr_t page_to_free,
uint64_t page_to_free_size,
Status &error) {
lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0);
ProcessSP process_sp(thread.CalculateProcess());
TargetSP target_sp(thread.CalculateTarget());
ClangASTContext *clang_ast_context = ClangASTContext::GetScratch(*target_sp);
Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME));
GetItemInfoReturnInfo return_value;
return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS;
return_value.item_buffer_size = 0;
error.Clear();
if (!thread.SafeToCallFunctions()) {
LLDB_LOGF(log, "Not safe to call functions on thread 0x%" PRIx64,
thread.GetID());
error.SetErrorString("Not safe to call functions on this thread.");
return return_value;
}
// Set up the arguments for a call to
// struct get_item_info_return_values
// {
// uint64_t item_info_buffer_ptr; /* the address of the items buffer
// from libBacktraceRecording */
// uint64_t item_info_buffer_size; /* the size of the items buffer from
// libBacktraceRecording */
// };
//
// void __lldb_backtrace_recording_get_item_info
// (struct
// get_item_info_return_values
// *return_buffer,
// int debug,
// uint64_t item,
// void *page_to_free,
// uint64_t page_to_free_size)
// Where the return_buffer argument points to a 24 byte region of memory
// already allocated by lldb in the inferior process.
CompilerType clang_void_ptr_type =
clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
Value return_buffer_ptr_value;
return_buffer_ptr_value.SetValueType(Value::eValueTypeScalar);
return_buffer_ptr_value.SetCompilerType(clang_void_ptr_type);
CompilerType clang_int_type = clang_ast_context->GetBasicType(eBasicTypeInt);
Value debug_value;
debug_value.SetValueType(Value::eValueTypeScalar);
debug_value.SetCompilerType(clang_int_type);
CompilerType clang_uint64_type =
clang_ast_context->GetBasicType(eBasicTypeUnsignedLongLong);
Value item_value;
item_value.SetValueType(Value::eValueTypeScalar);
item_value.SetCompilerType(clang_uint64_type);
Value page_to_free_value;
page_to_free_value.SetValueType(Value::eValueTypeScalar);
page_to_free_value.SetCompilerType(clang_void_ptr_type);
Value page_to_free_size_value;
page_to_free_size_value.SetValueType(Value::eValueTypeScalar);
page_to_free_size_value.SetCompilerType(clang_uint64_type);
std::lock_guard<std::mutex> guard(m_get_item_info_retbuffer_mutex);
if (m_get_item_info_return_buffer_addr == LLDB_INVALID_ADDRESS) {
addr_t bufaddr = process_sp->AllocateMemory(
32, ePermissionsReadable | ePermissionsWritable, error);
if (!error.Success() || bufaddr == LLDB_INVALID_ADDRESS) {
LLDB_LOGF(log, "Failed to allocate memory for return buffer for get "
"current queues func call");
return return_value;
}
m_get_item_info_return_buffer_addr = bufaddr;
}
ValueList argument_values;
return_buffer_ptr_value.GetScalar() = m_get_item_info_return_buffer_addr;
argument_values.PushValue(return_buffer_ptr_value);
debug_value.GetScalar() = 0;
argument_values.PushValue(debug_value);
item_value.GetScalar() = item;
argument_values.PushValue(item_value);
if (page_to_free != LLDB_INVALID_ADDRESS)
page_to_free_value.GetScalar() = page_to_free;
else
page_to_free_value.GetScalar() = 0;
argument_values.PushValue(page_to_free_value);
page_to_free_size_value.GetScalar() = page_to_free_size;
argument_values.PushValue(page_to_free_size_value);
addr_t args_addr = SetupGetItemInfoFunction(thread, argument_values);
DiagnosticManager diagnostics;
ExecutionContext exe_ctx;
EvaluateExpressionOptions options;
options.SetUnwindOnError(true);
options.SetIgnoreBreakpoints(true);
options.SetStopOthers(true);
#if __has_feature(address_sanitizer)
options.SetTimeout(process_sp->GetUtilityExpressionTimeout());
#else
options.SetTimeout(std::chrono::milliseconds(500));
#endif
options.SetTimeout(process_sp->GetUtilityExpressionTimeout());
options.SetTryAllThreads(false);
options.SetIsForUtilityExpr(true);
thread.CalculateExecutionContext(exe_ctx);
if (!m_get_item_info_impl_code) {
error.SetErrorString("Unable to compile function to call "
"__introspection_dispatch_queue_item_get_info");
return return_value;
}
ExpressionResults func_call_ret;
Value results;
FunctionCaller *func_caller = m_get_item_info_impl_code->GetFunctionCaller();
if (!func_caller) {
LLDB_LOGF(log, "Could not retrieve function caller for "
"__introspection_dispatch_queue_item_get_info.");
error.SetErrorString("Could not retrieve function caller for "
"__introspection_dispatch_queue_item_get_info.");
return return_value;
}
func_call_ret = func_caller->ExecuteFunction(exe_ctx, &args_addr, options,
diagnostics, results);
if (func_call_ret != eExpressionCompleted || !error.Success()) {
LLDB_LOGF(log,
"Unable to call "
"__introspection_dispatch_queue_item_get_info(), got "
"ExpressionResults %d, error contains %s",
func_call_ret, error.AsCString(""));
error.SetErrorString("Unable to call "
"__introspection_dispatch_queue_get_item_info() for "
"list of queues");
return return_value;
}
return_value.item_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory(
m_get_item_info_return_buffer_addr, 8, LLDB_INVALID_ADDRESS, error);
if (!error.Success() ||
return_value.item_buffer_ptr == LLDB_INVALID_ADDRESS) {
return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS;
return return_value;
}
return_value.item_buffer_size = m_process->ReadUnsignedIntegerFromMemory(
m_get_item_info_return_buffer_addr + 8, 8, 0, error);
if (!error.Success()) {
return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS;
return return_value;
}
LLDB_LOGF(log,
"AppleGetItemInfoHandler called "
"__introspection_dispatch_queue_item_get_info (page_to_free == "
"0x%" PRIx64 ", size = %" PRId64 "), returned page is at 0x%" PRIx64
", size %" PRId64,
page_to_free, page_to_free_size, return_value.item_buffer_ptr,
return_value.item_buffer_size);
return return_value;
}