AppleGetQueuesHandler.cpp
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//===-- AppleGetQueuesHandler.cpp -----------------------------------------===//
//
// 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 "AppleGetQueuesHandler.h"
#include "Plugins/TypeSystem/Clang/TypeSystemClang.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/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 *AppleGetQueuesHandler::g_get_current_queues_function_name =
"__lldb_backtrace_recording_get_current_queues";
const char *AppleGetQueuesHandler::g_get_current_queues_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 *introspection_dispatch_queue_info_t; \n\
\n\
extern uint64_t __introspection_dispatch_get_queues (queue_list_scope_t scope, \n\
introspection_dispatch_queue_info_t *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_current_queues_return_values \n\
{ \n\
uint64_t queues_buffer_ptr; /* the address of the queues buffer from libBacktraceRecording */ \n\
uint64_t queues_buffer_size; /* the size of the queues buffer from libBacktraceRecording */ \n\
uint64_t count; /* the number of queues included in the queues buffer */ \n\
}; \n\
\n\
void __lldb_backtrace_recording_get_current_queues \n\
(struct get_current_queues_return_values *return_buffer, \n\
int debug, \n\
void *page_to_free, \n\
uint64_t page_to_free_size) \n\
{ \n\
if (debug) \n\
printf (\"entering get_current_queues with args %p, %d, 0x%p, 0x%llx\\n\", return_buffer, debug, 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\
return_buffer->count = __introspection_dispatch_get_queues ( \n\
/* QUEUES_WITH_ANY_ITEMS */ 2, \n\
(void**)&return_buffer->queues_buffer_ptr, \n\
&return_buffer->queues_buffer_size); \n\
if (debug) \n\
printf(\"result was count %lld\\n\", return_buffer->count); \n\
} \n\
} \n\
";
AppleGetQueuesHandler::AppleGetQueuesHandler(Process *process)
: m_process(process), m_get_queues_impl_code_up(),
m_get_queues_function_mutex(),
m_get_queues_return_buffer_addr(LLDB_INVALID_ADDRESS),
m_get_queues_retbuffer_mutex() {}
AppleGetQueuesHandler::~AppleGetQueuesHandler() {}
void AppleGetQueuesHandler::Detach() {
if (m_process && m_process->IsAlive() &&
m_get_queues_return_buffer_addr != LLDB_INVALID_ADDRESS) {
std::unique_lock<std::mutex> lock(m_get_queues_retbuffer_mutex,
std::defer_lock);
(void)lock.try_lock(); // Even if we don't get the lock, deallocate the buffer
m_process->DeallocateMemory(m_get_queues_return_buffer_addr);
}
}
// Construct a CompilerType for the structure that
// g_get_current_queues_function_code will return by value so we can extract
// the fields after performing the function call. i.e. we are getting this
// struct returned to us:
//
// struct get_current_queues_return_values
// {
// introspection_dispatch_queue_info_t *queues_buffer;
// uint64_t queues_buffer_size;
// uint64_t count;
// };
// Compile our __lldb_backtrace_recording_get_current_queues() function (from
// the source above in g_get_current_queues_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_current_queues into the inferior
// process if needed.
//
// Write the get_queues_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
AppleGetQueuesHandler::SetupGetQueuesFunction(Thread &thread,
ValueList &get_queues_arglist) {
ThreadSP thread_sp(thread.shared_from_this());
ExecutionContext exe_ctx(thread_sp);
Address impl_code_address;
DiagnosticManager diagnostics;
Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME));
lldb::addr_t args_addr = LLDB_INVALID_ADDRESS;
FunctionCaller *get_queues_caller = nullptr;
// Scope for mutex locker:
{
std::lock_guard<std::mutex> guard(m_get_queues_function_mutex);
// First stage is to make the ClangUtility to hold our injected function:
if (!m_get_queues_impl_code_up) {
if (g_get_current_queues_function_code != nullptr) {
Status error;
m_get_queues_impl_code_up.reset(
exe_ctx.GetTargetRef().GetUtilityFunctionForLanguage(
g_get_current_queues_function_code, eLanguageTypeC,
g_get_current_queues_function_name, error));
if (error.Fail()) {
LLDB_LOGF(
log,
"Failed to get UtilityFunction for queues introspection: %s.",
error.AsCString());
return args_addr;
}
if (!m_get_queues_impl_code_up->Install(diagnostics, exe_ctx)) {
if (log) {
LLDB_LOGF(log, "Failed to install queues introspection");
diagnostics.Dump(log);
}
m_get_queues_impl_code_up.reset();
return args_addr;
}
} else {
if (log) {
LLDB_LOGF(log, "No queues introspection code found.");
diagnostics.Dump(log);
}
return LLDB_INVALID_ADDRESS;
}
}
// Next make the runner function for our implementation utility function.
TypeSystemClang *clang_ast_context =
TypeSystemClang::GetScratch(thread.GetProcess()->GetTarget());
CompilerType get_queues_return_type =
clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
Status error;
get_queues_caller = m_get_queues_impl_code_up->MakeFunctionCaller(
get_queues_return_type, get_queues_arglist, thread_sp, error);
if (error.Fail() || get_queues_caller == nullptr) {
LLDB_LOGF(log,
"Could not get function caller for get-queues function: %s.",
error.AsCString());
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_queues_caller->WriteFunctionArguments(
exe_ctx, args_addr, get_queues_arglist, diagnostics)) {
if (log) {
LLDB_LOGF(log, "Error writing get-queues function arguments.");
diagnostics.Dump(log);
}
return args_addr;
}
return args_addr;
}
AppleGetQueuesHandler::GetQueuesReturnInfo
AppleGetQueuesHandler::GetCurrentQueues(Thread &thread, 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());
TypeSystemClang *clang_ast_context = TypeSystemClang::GetScratch(*target_sp);
Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME));
GetQueuesReturnInfo return_value;
return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS;
return_value.queues_buffer_size = 0;
return_value.count = 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_current_queues_return_values
// {
// uint64_t queues_buffer_ptr; /* the address of the queues buffer from
// libBacktraceRecording */
// uint64_t queues_buffer_size; /* the size of the queues buffer from
// libBacktraceRecording */
// uint64_t count; /* the number of queues included in the
// queues buffer */
// };
//
// void
// __lldb_backtrace_recording_get_current_queues
// (struct
// get_current_queues_return_values
// *return_buffer,
// 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);
Value page_to_free_value;
page_to_free_value.SetValueType(Value::eValueTypeScalar);
page_to_free_value.SetCompilerType(clang_void_ptr_type);
CompilerType clang_uint64_type =
clang_ast_context->GetBasicType(eBasicTypeUnsignedLongLong);
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_queues_retbuffer_mutex);
if (m_get_queues_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_queues_return_buffer_addr = bufaddr;
}
ValueList argument_values;
return_buffer_ptr_value.GetScalar() = m_get_queues_return_buffer_addr;
argument_values.PushValue(return_buffer_ptr_value);
debug_value.GetScalar() = 0;
argument_values.PushValue(debug_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 = SetupGetQueuesFunction(thread, argument_values);
if (!m_get_queues_impl_code_up) {
error.SetErrorString(
"Unable to compile __introspection_dispatch_get_queues.");
return return_value;
}
FunctionCaller *get_queues_caller =
m_get_queues_impl_code_up->GetFunctionCaller();
if (get_queues_caller == nullptr) {
error.SetErrorString(
"Unable to get caller for call __introspection_dispatch_get_queues");
return return_value;
}
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.SetTryAllThreads(false);
options.SetIsForUtilityExpr(true);
thread.CalculateExecutionContext(exe_ctx);
ExpressionResults func_call_ret;
Value results;
func_call_ret = get_queues_caller->ExecuteFunction(
exe_ctx, &args_addr, options, diagnostics, results);
if (func_call_ret != eExpressionCompleted || !error.Success()) {
LLDB_LOGF(log,
"Unable to call introspection_get_dispatch_queues(), got "
"ExpressionResults %d, error contains %s",
func_call_ret, error.AsCString(""));
error.SetErrorString("Unable to call introspection_get_dispatch_queues() "
"for list of queues");
return return_value;
}
return_value.queues_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory(
m_get_queues_return_buffer_addr, 8, LLDB_INVALID_ADDRESS, error);
if (!error.Success() ||
return_value.queues_buffer_ptr == LLDB_INVALID_ADDRESS) {
return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS;
return return_value;
}
return_value.queues_buffer_size = m_process->ReadUnsignedIntegerFromMemory(
m_get_queues_return_buffer_addr + 8, 8, 0, error);
if (!error.Success()) {
return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS;
return return_value;
}
return_value.count = m_process->ReadUnsignedIntegerFromMemory(
m_get_queues_return_buffer_addr + 16, 8, 0, error);
if (!error.Success()) {
return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS;
return return_value;
}
LLDB_LOGF(log,
"AppleGetQueuesHandler called "
"__introspection_dispatch_get_queues (page_to_free == "
"0x%" PRIx64 ", size = %" PRId64 "), returned page is at 0x%" PRIx64
", size %" PRId64 ", count = %" PRId64,
page_to_free, page_to_free_size, return_value.queues_buffer_ptr,
return_value.queues_buffer_size, return_value.count);
return return_value;
}